103 results on '"Ntusi NAB"'
Search Results
2. Associations of HIV and prevalent type 2 diabetes mellitus in the context of obesity in South Africa
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Magodoro, IM, primary, Castle, AC, additional, Tshuma, N, additional, Goedecke, JH, additional, Sewpaul, R, additional, Manasa, J, additional, Manne-Goehler, J, additional, Ntusi, NAB, additional, Nyirenda, MJ, additional, and Siedner, MJ, additional
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- 2024
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3. A position statement and practical guide to the use of particulate filtering facepiece respirators (N95, FFP2, or equivalent) for South African health workers exposed to respiratory pathogens including Mycobacterium tuberculosis and SARS-CoV-2
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Dheda, K, Charalambous, S, Kharat, AS, von Delft, A, van Zyl-SMit, RN, Perumal, R, Allwood, BW, Esmail, A, Wong, ML, Duse, AG, Richards, G, Feldman, C, Mer, M, Nyamande, K, Lalla, U, Koegelenberg, CFN, Venter, F, Dawood, H, Adams, S, Ntusi, NAB, van der Westhuizen, H-M, Moosa, M-YS, van der Westhuizen, NA, Moultrie, H, Nel, J, Hausler, H, Preiser, W, Lasersohn, L, Zar, HJ, and Churchyard, GJ
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Summary\ud Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is transmitted mainly by aerosol in particles
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- 2021
4. Considering equity in global health collaborations: A qualitative study on experiences of equity
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Amo-Adjei, J, Faure, MC, Munung, NS, Ntusi, NAB, Pratt, B, de Vries, J, Amo-Adjei, J, Faure, MC, Munung, NS, Ntusi, NAB, Pratt, B, and de Vries, J
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International collaborations have become the standard model for global health research and often include researchers and institutions from high income countries (HICs) and low- and middle-income countries (LMICs). While such collaborations are important for generating new knowledge that will help address global health inequities, there is evidence to suggest that current forms of collaboration may reproduce unequal power relations. Therefore, we conducted a qualitative study with scientists, researchers and those involved in research management, working in international health collaborations. Interviews were conducted between October 2019 and March 2020. We conducted 13 interviews with 15 participants. From our findings, we derive three major themes. First, our results reflect characteristics of equitable, collaborative research relationships. Here we find both relational features, specifically trust and belonging, and structural features, including clear contractual agreements, capacity building, inclusive divisions of labour, and the involvement of local communities. Second, we discuss obstacles to develop equitable collaborations. These include exclusionary labour practices, donor-driven research agendas, overall research culture, lack of accountability and finally, the inadequate financing of indirect costs for LMIC institutions. Third, we discuss the responsibilities for promoting science equity of funders, LMIC researchers, LMIC institutions, and LMIC governments. While other empirical studies have suggested similar features of equity, our findings extend these features to include local communities as collaborators in research projects and not only as beneficiaries. We also suggest the importance of funders paying for indirect costs, without which the capacity of LMIC institutions will continually erode. And finally, our study shows the responsibilities of LMIC actors in developing equitable collaborations, which have largely been absent from the literature.
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- 2021
5. Mapping experiences and perspectives of equity in international health collaborations: a scoping review
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Faure, MC, Munung, NS, Ntusi, NAB, Pratt, B, de Vries, J, Faure, MC, Munung, NS, Ntusi, NAB, Pratt, B, and de Vries, J
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BACKGROUND: Whilst global health research often involves international collaborations, achieving or promoting equity within collaborations remains a key challenge, despite established conceptual approaches and the development of frameworks and guidelines to promote equity. There have also been several empirical studies documenting researchers' experiences of inequity and views on what is required to advance equity in global health collaborations. While these empirical studies provide critical insights, there has been no attempt to systematically synthetize what constitutes equity and how it can be achieved. To address this gap, we conducted a scoping review of qualitative studies, opinion and editorial pieces about what equity is and how it can be promoted in international collaborations. METHODS: We conducted a scoping review to explore domains of equity in international health collaborations. This review included qualitative studies and opinion pieces or editorial pieces on equity in international health collaborations. We mapped the data and identified common themes using a thematic analysis approach. RESULTS: This initial search retrieved a total of 7611 papers after removing duplicates. A total of 11 papers were included in this review, 10 empirical studies and 1 editorial piece. We conducted our search between October - November 2019. We identified 10 key domains which are important for promoting equity in international collaborations: funding; capacity building; authorship; sample ownership and export; trust; research agreement; acknowledging inequality; recognition and communication. DISCUSSION: Our findings suggest that for international collaborations to be considered more equitable, it must at least consider the 10 domains we highlighted. The 10 domains map onto five key aspects of social justice theory, namely avoiding unequal power relations like subordination, group recognition and affirmation, promoting the well-being of all, inclusion in decision-mak
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- 2021
6. COVID-19 and myocardial injury
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Herrey, AS, primary, Mohiddin, SA, additional, Letuka, p, additional, and Ntusi, NAB, additional
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- 2020
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7. COVID-19 and the cardiovascular system in pregnancy
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Herrey, AS, primary, Osman, A, additional, Soma-Pillay, P, additional, Sliwa, K, additional, and Ntusi, NAB, additional
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- 2020
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8. Improvements in ECG accuracy for diagnosis of left ventricular hypertrophy in obesity
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Rider, OJ, Ntusi, NAB, Bull, SC, Nethonda, R, Ferreira, V, Holloway, CJ, Holdsworth, D, Mahmod, M, Rayner, JJ, Banerjee, R, Myerson, SG, Watkins, HC, and Neubauer, SK
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Adult ,Male ,Action Potentials ,Reproducibility of Results ,Signal Processing, Computer-Assisted ,Middle Aged ,Magnetic Resonance Imaging ,Body Mass Index ,Special Populations ,Electrocardiography ,Heart Conduction System ,Heart Rate ,Predictive Value of Tests ,Humans ,Female ,Hypertrophy, Left Ventricular ,cardiovascular diseases ,Obesity ,Aged ,Retrospective Studies - Abstract
Objectives The electrocardiogram (ECG) is the most commonly used tool to screen for left ventricular hypertrophy (LVH), and yet current diagnostic criteria are insensitive in modern increasingly overweight society. We propose a simple adjustment to improve diagnostic accuracy in different body weights and improve the sensitivity of this universally available technique. Methods The electrocardiogram (ECG) is the most commonly used tool to screen for left ventricular hypertrophy (LVH), and yet current diagnostic criteria are insensitive in modern increasingly overweight society. We propose a simple adjustment to improve diagnostic accuracy in different body weights and improve the sensitivity of this universally available technique. Results When matched for left ventricular mass, the combination of leftward anatomical axis deviation and increased BMI resulted in a reduction of the Sokolow-Lyon index, by 4mm in overweight and 8mm in obesity. After adjusting for this in the initial cohort, the sensitivity of the Sokolow-Lyon index increased (overweight; 12.8% to 30.8%, obese 3.1% to 27.2%) approaching that in normal weight (37.8%). Similar results were achieved in the validation cohort (specificity increase overweight; 8.3% to 39.1%, obese 9.4% to 25.0%) again approaching normal weight (39.0%). Importantly, specificity remained excellent (>93.1%). Conclusion Adjusting the Sokolow-Lyon index for BMI (overweight +4mm, obesity +8mm) improves the diagnostic accuracy for detecting LVH. As the ECG, worldwide, remains the most widely used screening tool for LVH, implementing these findings should translate into significant clinical benefit.
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- 2016
9. Myocardial Perfusion Is Impaired and Relates to Cardiac Dysfunction in Patients With Atrial Fibrillation Both Before and After Successful Catheter Ablation
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Kim Rajappan, Timothy R. Betts, V Ferreira, F Notaristefano, T D Karamitsos, Ntusi Nab., Michael Jerosch-Herold, Alexander G. Liu, Stefan Neubauer, Matthew Ginks, Yaver Bashir, Barbara Casadei, and Rohan S. Wijesurendra
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Male ,medicine.medical_specialty ,cardiovascular magnetic resonance imaging ,medicine.medical_treatment ,Magnetic Resonance Imaging (MRI) ,Myocardial Ischemia ,Magnetic Resonance Imaging, Cine ,Catheter ablation ,030204 cardiovascular system & hematology ,myocardial blood flow ,Ventricular Function, Left ,030218 nuclear medicine & medical imaging ,Cardiac dysfunction ,Coronary artery disease ,left ventricular function ,03 medical and health sciences ,0302 clinical medicine ,Coronary Circulation ,Internal medicine ,Atrial Fibrillation ,Ventricular Dysfunction ,medicine ,Humans ,Arrhythmia and Electrophysiology ,In patient ,Myocardial infarction ,Aged ,Original Research ,business.industry ,Myocardial Perfusion Imaging ,Atrial fibrillation ,Middle Aged ,medicine.disease ,Coronary Vessels ,Magnetic Resonance Imaging ,Case-Control Studies ,Microvessels ,cardiovascular system ,Catheter Ablation ,Exercise Test ,Cardiology ,Atrial Function, Left ,Female ,Cardiology and Cardiovascular Medicine ,business ,Perfusion ,myocardial perfusion ,circulatory and respiratory physiology - Abstract
Background Atrial fibrillation ( AF ) is associated with myocardial infarction, and patients with AF and no obstructive coronary artery disease can present with symptoms and evidence of cardiac ischemia. We hypothesized that microvascular coronary dysfunction underlies these observations. Methods and Results Myocardial blood flow ( MBF ) at baseline and during adenosine stress and left ventricular and left atrial function were evaluated by magnetic resonance in 49 patients with AF (25 paroxysmal, 24 persistent) with no history of epicardial coronary artery disease or diabetes mellitus, before and 6 to 9 months after ablation. Findings were compared with those obtained in matched controls in sinus rhythm (n=25). Before ablation, patients with AF had impaired left atrial function and left ventricular ejection fraction and strain indices (all P MBF was impaired in patients both under baseline conditions (1.21±0.24 mL/min per g·[mm Hg·bpm/10 4 ] −1 versus 1.34±0.28 mL/min per g·[mm Hg·bpm/10 4 ] −1 in controls, P =0.044) and during adenosine stress (2.29±0.48 mL/min per g versus 2.73±0.37 mL/min per g in controls, P MBF correlated with left ventricular strain and left atrial function (all P ≤0.001), so that cardiac function was most impaired in patients with the lowest MBF . Baseline and stress MBF remained unchanged postablation (both P =ns), and baseline MBF showed similar correlations with functional indices to those present preablation (all P ≤0.001). Conclusions Baseline and stress MBF are significantly impaired in patients with AF but no epicardial coronary artery disease. Reduction in MBF is proportional to severity of left ventricular and left atrial dysfunction, even after successful ablation. Coronary microvascular dysfunction may be a relevant pathophysiological mechanism in patients with a history of AF .
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- 2018
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10. An approach to the clinical assessment and management of syncope in adults
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Ntusi, NAB, Coccia, CBI, Cupido, BJ, and Chin, A
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Syncope, defined as a brief loss of consciousness due to an abrupt fall in cerebral perfusion, remains a frequent reason for medical presentation. The goals of the clinical assessment of a patient with syncope are twofold: (i) to identify the precise cause in order to implement a mechanism-specific and effective therapeutic strategy; and (ii) to quantify the risk to the patient, which depends on the underlying disease, rather than the mechanism of the syncope. Hence, a structured approach to the patient with syncope is required. History-taking remains the most important aspect of the clinical assessment. The classification of syncope is based on the underlying pathophysiological mechanism causing the event, and includes cardiac, orthostatic and reflex (neurally mediated) mechanisms. Reflex syncope can be categorised into vasovagal syncope (from emotional or orthostatic stress), situational syncope (due to specific situational stressors), carotid sinus syncope (from pressure on the carotid sinus, e.g. shaving or a tight collar), and atypical reflex syncope (episodes of syncope or reflex syncope that cannot be attributed to a specific trigger or syncope with an atypical presentation). Cardiovascular causes of syncope may be structural (mechanical) or electrical. Orthostatic hypotension is caused by an abnormal drop in systolic blood pressure upon standing, and is defined as a decrease of >20 mmHg in systolic blood pressure or a reflex tachycardia of >20 beats/minute within 3 minutes of standing. The main causes of orthostatic hypotension are autonomic nervous system failure and hypovolaemia. Patients with life-threatening causes of syncope should be managed urgently and appropriately. In patients with reflex or orthostatic syncope it is important to address any exacerbating medication and provide general measures to increase blood pressure, such as physical counter-pressure manoeuvres. Where heart disease is found to be the cause of the syncope, a specialist opinion is warranted and where possible the problem should be corrected. It is important to remember that in any patient presenting with syncope the main objectives of management are to prolong survival, limit physical injuries and prevent recurrences. This can only be done if a patient is appropriately assessed at presentation, investigated as clinically indicated, and subsequently referred to a cardiologist for appropriate management.
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- 2015
11. Case report: Digoxin therapy in the modern management of cardiovascular disease: An unusual but serious complication
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Mkoko, P, Mokhele, N, Ntsekhe, M, and Ntusi, NAB
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A 67-year-old woman presented to the Emergency Unit, Groote Schuur Hospital, Cape Town, South Africa, with a 1-week history of poor appetite, vomiting and fatigue. Her background history was notable for infundibular pulmonary stenosis resection, pulmonary embolism and atrial flutter. Two days before, she complained to her general practitioner of recent-onset, recurrent syncope and worsening gastrointestinal upset. Her medical treatment included warfarin 5 mg daily, enalapril 5 mg twice daily, furosemide 40 mg twice daily, atenolol 50 mg twice daily, amiodarone 200 mg daily and digoxin 0.125 mg daily. The digoxin was added to her therapy 8 months earlier to optimise rate control.
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- 2015
12. Clinical features, spectrum of causal genetic mutations and outcome of hypertrophic cardiomyopathy in South Africans
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Ntusi, NAB, primary, Shaboodien, G, additional, Badri, M, additional, Gumedze, F, additional, and Mayosi, BM, additional
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- 2016
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13. Diagnosing cardiac disease during pregnancy: imaging modalities
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Ntusi, NAB, primary, Samuels, P, additional, Moosa, S, additional, and Mocumbi, AO, additional
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- 2016
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14. The commitment of the human cell atlas to humanity.
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Amit I, Ardlie K, Arzuaga F, Awandare G, Bader G, Bernier A, Carninci P, Donnelly S, Eils R, Forrest ARR, Greely HT, Guigo R, Hacohen N, Haniffa M, Kirby ES, Knoppers BM, Kriegstein A, Lein ES, Linnarsson S, Majumder PP, Merad M, Meyer K, Mhlanga MM, Nolan G, Ntusi NAB, Pe'er D, Prabhakar S, Raven-Adams M, Regev A, Rozenblatt-Rosen O, Saha S, Saltzman A, Shalek AK, Shin JW, Stunnenberg H, Teichmann SA, Tickle T, Villani AC, Wells C, Wold B, Yang H, and Zhuang X
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- Humans, Atlases as Topic
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The Human Cell Atlas (HCA) is a global partnership "to create comprehensive reference maps of all human cells-the fundamental units of life - as a basis for both understanding human health and diagnosing, monitoring, and treating disease." ( https://www.humancellatlas.org/ ) The atlas shall characterize cells from diverse individuals across the globe to better understand human biology. HCA proactively considers the priorities of, and benefits accrued to, contributing communities. Here, we lay out principles and action items that have been adopted to affirm HCA's commitment to equity so that the atlas is beneficial to all of humanity., Competing Interests: Competing interests: A.R. is an employee of Genentech, a member of the Roche group, and has equity in Roche. A.R. was a co-founder and equity holder of Celsius Therapeutics, is an equity holder in Immunitas, and until July 31, 2020 was an S.A.B. member of Thermo Fisher Scientific, Syros Pharmaceuticals, Neogene Therapeutics and Asimov. A.R. is an inventor on multiple patents related to single cell and spatial genomics. All other authors declare no competing interests., (© 2024. The Author(s).)
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- 2024
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15. A Response to: Letter to the Editor Regarding "Comparing Cardiovascular Outcomes and Costs of Perindopril-, Enalapril- or Losartan-Based Antihypertensive Regimens in South Africa: Real-World Medical Claims Database Analysis".
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Snyman JR, Gumedze F, Jones ESW, Alaba OA, Tsabedze N, Vira A, and Ntusi NAB
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Competing Interests: Declarations Conflict of Interest Jacques R. Snyman has received honoraria from Servier. Freedom Gumedze has received honoraria from Servier. Erika S. W. Jones has received sponsorship and honoraria from Servier and Pharmadynamics. Olufunke A. Alaba has received honoraria from Servier. Nqoba Tsabedze has received consultation fees from Novartis Pharmaceuticals, Novo Nordisk, Boston Scientific, Pfizer, Servier, Phillips, Takeda, AstraZeneca, Acino Health Care Group and Merck; and educational and travel grants from Medtronic, Biotronik, Boston Scientific and Vertice Health Care Group. Alykhan Vira is an employee of Quantium Health South Africa. Ntobeko A. B. Ntusi acknowledges support from the South African Medical Research Council, National Research Foundation and the Lily and Ernst Hausmann Trust; unrestricted educational grants from Siemens, General Electric, Philips and CVI42. Ntobeko Ntusi has changed his affiliation to the South African Medical Research Council. Ethical Approval This article is based on previously conducted studies and does not contain any new studies with human participants or animals performed by any of the authors.
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- 2024
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16. Association Between Mycobacterium tuberculosis Sensitization and Insulin Resistance Among US Adults Screened for Type 2 Diabetes Mellitus.
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Magodoro IM, Aluoch A, Claggett B, Nyirenda MJ, Siedner MJ, Wilkinson KA, Wilkinson RJ, and Ntusi NAB
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Background: Type 2 diabetes mellitus (T2DM) may be a long-term sequela of infection with Mycobacterium tuberculosis ( Mtb ) by mechanisms that remain to be fully explained. We evaluated the association between Mtb sensitization and T2DM and, via mediation analysis, the extent to which it is mediated by insulin resistance and/or β-cell failure., Methods: Adults were assessed for T2DM by fasting plasma glucose, 2-hour oral glucose tolerance testing, and hemoglobin A
1c ; β-cell dysfunction and insulin resistance by homoeostasis model assessment 2; and Mtb sensitization by tuberculin skin testing. Associations between Mtb sensitization and T2DM were modeled with probit regression and decomposed into indirect effects of β-cell dysfunction and insulin resistance. Analyses were adjusted for sociodemographic, behavioral, and clinical characteristics., Results: We included 1843 adults. Individuals with Mtb sensitization were older than those without Mtb (median [IQR], 54 [39-64] vs 47 [33-62] years). As compared with being uninfected, Mtb sensitization was associated with T2DM (adjusted absolute risk difference, 9.34% [95% CI, 2.38%-15.0%]; P < .001) and increased insulin resistance (adjusted median difference, 0.16 [95% CI, .03-.29]; P = .014) but not β-cell dysfunction (adjusted median difference, -3.1 [95% CI, -10.4 to 4.3]; P = .42). In mediation analyses, insulin resistance mediated 18.3% (95% CI, 3.29%-36.0%; P = .020) of the total effect of the association between Mtb sensitization and T2DM., Conclusions: Definitive prospective studies examining incident T2DM following tuberculosis are warranted. Notwithstanding, our findings suggest that exposure to Mtb may be a novel risk factor for T2DM, likely driven by an increase in insulin resistance., Competing Interests: Potential conflicts of interest. All authors: No reported conflicts., (© The Author(s) 2024. Published by Oxford University Press on behalf of Infectious Diseases Society of America.)- Published
- 2024
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17. Subclinical Myocardial Fibrosis in South African Youth With HIV: Results From the CTAAC-Heart Study.
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Jao J, Zar HJ, Kahts M, Jermy S, Egan D, Nyathi MN, Asafu-Agyei NA, Legbedze J, Carkeek E, Jele N, Mautsa T, Bonner LB, McComsey GA, Feinstein M, Kurland IJ, Myer L, and Ntusi NAB
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Background: Few data exist on myocardial fibrosis and inflammation in youth with HIV., Methods: We performed cardiovascular magnetic resonance (CMR) on a cross section of South African youth: youth with perinatally acquired HIV (YPHIV) undergoing antiretroviral therapy (ART), youth with nonperinatally acquired HIV (YNPHIV) receiving ART, and youth without HIV. Quantile regression models were fit to assess the association between HIV status and CMR outcomes: subclinical fibrosis (late gadolinium enhancement [LGE] mass and fraction, native T1, extracellular volume) and inflammation (native T1, T2 mapping)., Results: Of 464 youth, 287 were YPHIV, 87 were YNPHIV, and 90 were HIV seronegative. The median age was 16 years (range, 11-24). LGE mass was higher in YPHIV and YNPHIV than in youth who were HIV seronegative (1.85 vs 2.00 vs 1.41 g, respectively), as was fraction (5.8% vs 6.4% vs 4.5%); native T1 was highest in YNPHIV. In adjusted analyses, when compared with youth with HIV seronegativity, YPHIV and YNPHIV exhibited higher LGE mass (β = 0.468, P = .001; β = 0.544, P = .002) and LGE fraction (β = 1.587, P < .001; β = 1.781, P < .001). CMR outcomes were similar between YPHIV and YNPHIV., Conclusions: Despite ART use, YPHIV and YNPHIV appear to have higher subclinical myocardial fibrosis than youth who are HIV seronegative and healthy adults in South Africa and may benefit from early screening/monitoring for cardiovascular disease., Competing Interests: Potential conflicts of interest. All authors: No reported conflicts., (© The Author(s) 2024. Published by Oxford University Press on behalf of Infectious Diseases Society of America.)
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- 2024
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18. Scan With Me: A Train-the-Trainer Program to Upskill MRI Personnel in Low- and Middle-Income Countries.
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Mumuni AN, Eyre K, Montalba C, Harrison A, Maharjan S, Botwe F, Garcia MF, Zeraii A, Friedrich MG, Fatade A, Ntusi NAB, Lim T, Garg R, Umair M, Ninalowo HA, Adeleke S, Anosike C, Dako F, and Anazodo UC
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- Humans, Program Evaluation, Clinical Competence, Female, Male, Technology, Radiologic education, Pilot Projects, Developing Countries, Magnetic Resonance Imaging, Curriculum
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Purpose: Access to MRI in low- and middle-income countries (LMICs) remains among the poorest in the world. The lack of skilled MRI personnel exacerbates access gaps, reinforcing long-standing health disparities. The Scan With Me (SWiM) program aims to sustainably create a network of highly skilled MRI technologists in LMICs who will facilitate the transfer of MRI knowledge and skills to their peers and contribute to the implementation of highly valuable imaging protocols for effective clinical and research use., Methods: The program introduces a case-based curriculum designed using a novel train-the-trainer approach, integrated with peer-collaborative learning to upskill practicing MRI technologists in LMICs. The 6-week curriculum uses the teach-try-use approach, which combines self-paced didactic lectures covering the basics of MR image acquisition (teach) with hands-on expert-guided scanning experience (try) and the implementation of protocols tailored to provide the best possible images on their infrastructures (use). Each program includes research translation skills training using an established advanced MRI technique relevant to LMICs. A pilot program focused on cardiac MRI (CMR) was conducted to assess the program's curriculum, delivery, and evaluation methods., Results: Forty-three MRI technologists from 16 LMICs participated in the pilot CMR program and, over the course of the training, implemented optimized CMR protocols that reduced acquisition times while improving image quality. The training resources and scanner-specific standardized protocols are published openly for public use in an online repository. In general, at the end of the program, learners reported considerable improvements in CMR knowledge and skills. All respondents to the program evaluation survey agreed to recommend the program to their colleagues, while 87% indicated interest in returning to help train others., Conclusions: The SWiM program is the first master class in MRI acquisition for practicing imaging technologists in LMICs. The program holds the potential to help reduce disparities in MRI expertise and access. The support of the MRI community, imaging societies, and funding agencies will increase its reach and further its impact in democratizing MRI., (Copyright © 2024 American College of Radiology. Published by Elsevier Inc. All rights reserved.)
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- 2024
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19. Clinical Characteristics and Mechanisms of Acute Myocarditis.
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Heymans S, Van Linthout S, Kraus SM, Cooper LT, and Ntusi NAB
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- Humans, Acute Disease, Male, Female, Adult, Middle Aged, Young Adult, Myocarditis
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Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT05335928., Competing Interests: S. Heymans receives personal fees for independent scientific advice on early development in the field of heart failure for AstraZeneca, Ribocure, and CSL Behring, and receives research support from AstraZeneca and CSL Behring.
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- 2024
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20. Bringing MRI to low- and middle-income countries: Directions, challenges and potential solutions.
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Murali S, Ding H, Adedeji F, Qin C, Obungoloch J, Asllani I, Anazodo U, Ntusi NAB, Mammen R, Niendorf T, and Adeleke S
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- Humans, Income, Magnetic Resonance Imaging, Developing Countries
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The global disparity of magnetic resonance imaging (MRI) is a major challenge, with many low- and middle-income countries (LMICs) experiencing limited access to MRI. The reasons for limited access are technological, economic and social. With the advancement of MRI technology, we explore why these challenges still prevail, highlighting the importance of MRI as the epidemiology of disease changes in LMICs. In this paper, we establish a framework to develop MRI with these challenges in mind and discuss the different aspects of MRI development, including maximising image quality using cost-effective components, integrating local technology and infrastructure and implementing sustainable practices. We also highlight the current solutions-including teleradiology, artificial intelligence and doctor and patient education strategies-and how these might be further improved to achieve greater access to MRI., (© 2023 The Authors. NMR in Biomedicine published by John Wiley & Sons Ltd.)
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- 2024
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21. Cardioprotective effects of early versus late initiated antiretroviral treatment in adolescents with perinatal HIV-1 infection.
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Magodoro IM, Guerrero-Chalela CE, Claggett B, Jermy S, Samuels P, Myer L, Zar HJ, Jao J, Ntsekhe M, Siedner MJ, and Ntusi NAB
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- Humans, Female, Adolescent, Male, HIV-1 drug effects, Magnetic Resonance Imaging, Child, Anti-HIV Agents therapeutic use, Anti-HIV Agents administration & dosage, Anti-Retroviral Agents administration & dosage, Anti-Retroviral Agents therapeutic use, Infectious Disease Transmission, Vertical prevention & control, Child, Preschool, HIV Infections drug therapy
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Whether, and how, cardioprotective effects of antiretroviral treatment (ART) in adolescents with perinatal HIV infection (APHIV) vary with age at treatment initiation is unknown. We used magnetic resonance imaging to compare cardiac status between APHIV initiated on ART at < 5 years of age (early ART, n = 37) and ≥ 5 years of age (delayed ART, n = 34) versus HIV-uninfected peers (n = 21), reporting z-score mean differences adjusted for confounders. Relative to HIV-uninfected adolescents, APHIV with early ART had higher left ventricular (LV) global circumferential strain (GCS) [adjusted mean (95%CI) z-score: 0.53 (0.13, 0.92)] and maximum indexed left atrium volume (LAVi) [adjusted z-score: 0.55 (0.08, 1.02)]. In contrast, APHIV with delayed ART had greater indexed LV end-diastolic volume (LVEDVi) [adjusted z-score: 0.47 (0.09, 0.86)] and extracellular volume fraction [adjusted z-score: 0.79 (0.20, 1.37)], but lower GCS [adjusted z-score: -0.51 (-0.91, -0.10)] than HIV-uninfected peers. APHIV had distinct albeit subclinical cardiac phenotypes depending on ART initiation age. Changes in early ART suggested comparatively worse diastology with preserved systolic function while delayed ART was associated with comparatively increased diffuse fibrosis and LV dilatation with reduced systolic function. The long-term clinical significance of these changes remains to be determined., (© 2024. The Author(s).)
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- 2024
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22. A study protocol to characterise pathophysiological and molecular markers of rheumatic heart disease and degenerative aortic stenosis using multiparametric cardiovascular imaging and multiomics techniques.
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Mutithu DW, Aremu OO, Mokaila D, Bana T, Familusi M, Taylor L, Martin LJ, Heathfield LJ, Kirwan JA, Wiesner L, Adeola HA, Lumngwena EN, Manganyi R, Skatulla S, Naidoo R, and Ntusi NAB
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- Humans, Case-Control Studies, Cross-Sectional Studies, Male, Female, Metabolomics methods, Echocardiography methods, Proteomics methods, Magnetic Resonance Imaging methods, Multiomics, Rheumatic Heart Disease diagnostic imaging, Rheumatic Heart Disease physiopathology, Rheumatic Heart Disease metabolism, Aortic Valve Stenosis diagnostic imaging, Aortic Valve Stenosis metabolism, Aortic Valve Stenosis physiopathology, Biomarkers metabolism
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Introduction: Rheumatic heart disease (RHD), degenerative aortic stenosis (AS), and congenital valve diseases are prevalent in sub-Saharan Africa. Many knowledge gaps remain in understanding disease mechanisms, stratifying phenotypes, and prognostication. Therefore, we aimed to characterise patients through clinical profiling, imaging, histology, and molecular biomarkers to improve our understanding of the pathophysiology, diagnosis, and prognosis of RHD and AS., Methods: In this cross-sectional, case-controlled study, we plan to recruit RHD and AS patients and compare them to matched controls. Living participants will undergo clinical assessment, echocardiography, CMR and blood sampling for circulatory biomarker analyses. Tissue samples will be obtained from patients undergoing valve replacement, while healthy tissues will be obtained from cadavers. Immunohistology, proteomics, metabolomics, and transcriptome analyses will be used to analyse circulatory- and tissue-specific biomarkers. Univariate and multivariate statistical analyses will be used for hypothesis testing and identification of important biomarkers. In summary, this study aims to delineate the pathophysiology of RHD and degenerative AS using multiparametric CMR imaging. In addition to discover novel biomarkers and explore the pathomechanisms associated with RHD and AS through high-throughput profiling of the tissue and blood proteome and metabolome and provide a proof of concept of the suitability of using cadaveric tissues as controls for cardiovascular disease studies., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Mutithu et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)
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- 2024
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23. Greater Disease Severity and Worse Clinical Outcomes in Patients Hospitalised with COVID-19 in Africa.
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Hahnle L, Mennen M, Gumedze F, Mutithu D, Adriaanse M, Egan D, Mazondwa S, Walters R, Appiah LT, Inofomoh F, Ogah O, Adekanmbi O, Goma F, Ogola E, Mwazo K, Suliman A, Singh K, Raspail L, Prabhakaran D, Perel P, Sliwa K, and Ntusi NAB
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- Adult, Humans, Prospective Studies, COVID-19 Vaccines, Africa epidemiology, Risk Factors, Retrospective Studies, COVID-19 epidemiology, COVID-19 complications, Acute Kidney Injury epidemiology
- Abstract
Background: COVID-19 cardiovascular research from Africa is limited. This study describes cardiovascular risk factors, manifestations, and outcomes of patients hospitalised with COVID-19 in the African region, with an overarching goal to investigate whether important differences exist between African and other populations, which may inform health policies., Methods: A multinational prospective cohort study was conducted on adults hospitalised with confirmed COVID-19, consecutively admitted to 40 hospitals across 23 countries, 6 of which were African countries. Of the 5,313 participants enrolled globally, 948 were from African sites (n = 9). Data on demographics, pre-existing conditions, clinical outcomes in hospital (major adverse cardiovascular events (MACE), renal failure, neurological events, pulmonary outcomes, and death), 30-day vitality status and re-hospitalization were assessed, comparing African to non-African participants., Results: Access to specialist care at African sites was significantly lower than the global average (71% vs. 95%), as were ICU admissions (19.4% vs. 34.0%) and COVID-19 vaccination rates (0.6% vs. 7.4%). The African cohort was slightly younger than the non-African cohort (55.0 vs. 57.5 years), with higher rates of hypertension (48.8% vs. 46.9%), HIV (5.9% vs. 0.3%), and Tuberculosis (3.6% vs. 0.3%). In African sites, a higher proportion of patients suffered cardiac arrest (7.5% vs. 5.1%) and acute kidney injury (12.7% vs. 7.2%), with acute kidney injury (AKI) appearing to be one of the strongest predictors of MACE and death in African populations compared to other populations. The overall mortality rate was significantly higher among African participants (18.2% vs. 14.2%)., Conclusions: Overall, hospitalised African patients with COVID-19 had a higher mortality despite a lower mean age, contradicting literature that had previously reported a lower mortality attributed to COVID-19 in Africa. African sites had lower COVID-19 vaccination rates and higher AKI rates, which were positively associated with increased mortality. In conclusion, African patients were hospitalized with more severe COVID-19 cases and had poorer outcomes., Competing Interests: The authors have no competing interests to declare., (Copyright: © 2024 The Author(s).)
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- 2024
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24. High-flow nasal oxygen in resource-constrained, non-intensive, high-care wards for COVID-19 acute hypoxaemic respiratory failure: Comparing outcomes of the first v. third waves at a tertiary centre in South Africa.
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Audley G, Raubenheimer P, Symons G, Mendelson M, Meintjes G, Ntusi NAB, Wasserman S, Dlamini S, Dheda K, van Zyl-Smit R, and Calligaro G
- Abstract
Background: High-flow nasal oxygen (HFNO) is an accepted treatment for severe COVID-19-related acute hypoxaemic respiratory failure (AHRF)., Objectives: To determine whether treatment outcomes at Groote Schuur Hospital, Cape Town, South Africa, during the third COVID-19 wave would be affected by increased institutional experience and capacity for HNFO and more restrictive admission criteria for respiratory high-care wards and intensive care units., Methods: We included consecutive patients with COVID-19-related AHRF treated with HFNO during the first and third COVID-19 waves. The primary endpoint was comparison of HFNO failure (composite of the need for intubation or death while on HFNO) between waves., Results: A total of 744 patients were included: 343 in the first COVID-19 wave and 401 in the third. Patients treated with HFNO in the first wave were older (median (interquartile range) age 53 (46 - 61) years v. 47 (40 - 56) years; p<0.001), and had higher prevalences of diabetes (46.9% v. 36.9%; p=0.006), hypertension (51.0% v. 35.2%; p<0.001), obesity (33.5% v. 26.2%; p=0.029) and HIV infection (12.5% v. 5.5%; p<0.001). The partial pressure of arterial oxygen to fraction of inspired oxygen (PaO
2 /FiO2 ) ratio at HFNO initiation and the ratio of oxygen saturation/FiO2 to respiratory rate within 6 hours (ROX-6 score) after HFNO commencement were lower in the first wave compared with the third (median 57.9 (47.3 - 74.3) mmHg v. 64.3 (51.2 - 79.0) mmHg; p=0.005 and 3.19 (2.37 - 3.77) v. 3.43 (2.93 - 4.00); p<0.001, respectively). The likelihood of HFNO failure (57.1% v. 59.6%; p=0.498) and mortality (46.9% v. 52.1%; p=0.159) did not differ significantly between the first and third waves., Conclusion: Despite differences in patient characteristics, circulating viral variant and institutional experience with HFNO, treatment outcomes were very similar in the first and third COVID-19 waves. We conclude that once AHRF is established in COVID-19 pneumonia, the comorbidity profile and HFNO provider experience do not appear to affect outcome., Study Synopsis: What the study adds. This study adds to the body of evidence demonstrating the utility of high-flow nasal oxygen (HFNO) in avoiding invasive mechanical ventilation (IMV) in patients with severe COVID-19 hypoxaemic respiratory failure, and shows that this utility remained consistent across different waves of the COVID-19 pandemic. Implications of the study. In resource-constrained settings, HFNO is a feasible non-invasive alternative to IMV and can be employed with favourable and consistent outcomes outside traditional critical care wards. It also confirms that the degree of gas exchange abnormality, and not pre-existing patient-related factors, circulating wave variant or provider experience, is the main predictor of HFNO failure., (Copyright © 2023, Audley et al.)- Published
- 2024
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25. Insulin resistance, and not β-cell impairment, mediates association between Mycobacterium tuberculosis sensitization and type II diabetes mellitus among US adults.
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Magodoro IM, Aluoch A, Claggett B, Nyirenda MJ, Siedner MJ, Wilkinson KA, Wilkinson RJ, and Ntusi N
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Type 2 diabetes mellitus (T2DM) may be a long-term sequela of infection with Mycobacterium tuberculosis (M.tb) by mechanisms that remain to be fully explained. We evaluated association between M.tb sensitization and T2DM among U.S adults and, via formal mediation analysis, the extent to which this association is mediated by insulin resistance and/or β-cell failure. These evaluations accounted for demographic, socio-economic, behavioral and clinical characteristics. T2DM was assessed by fasting plasma glucose, 2-hour oral glucose tolerance testing and HbA1c; homoeostasis model assessment 2 (HOMA2) was used to estimate β-cell dysfunction (HOMA2-B) and insulin resistance (HOMA2-IR); while M.tb sensitization status was ascertained by tuberculin skin testing (TST). Exposure to M.tb was associated with increased risk for T2DM, likely driven by an increase in insulin resistance. Definitive prospective studies examining incident T2DM following tuberculosis are warranted., Research in Context: What is already known about this subject?: Accumulating evidence suggests that pre-diabetes and new-onset type 2 diabetes mellitus (T2DM) may be a long-term complication of exposure to Mycobacterium tuberculosis ( M.tb ) via mechanisms that remain to be unraveled What is the key question?: To what extent do insulin resistance and β-cell failure mediate the association between M.tb sensitization with T2DM among US adults? What are the new findings?: M.tb sensitization is characterized by distinct glucose metabolic disturbances manifesting as increased risk of T2DM and isolated impaired fasting glucose (IFG) Insulin resistance, and not β-cell impairment, likely independently mediate the observed diabetogenic effects of M.tb sensitization How might this impact on clinical and/or public health practice in the foreseeable future?: If corroborated by prospective studies, both TB programs and individual clinical care must incorporate monitoring of serum glucose and long-term metabolic outcomesThis will be particularly urgent in sub-Saharan Africa and South-East Asia where scarce health resources coincide with overlapping endemic TB and epidemic T2DM.
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- 2024
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26. Clinical and cardiovascular magnetic resonance profile of cardiomyopathy patients from South Africa: Pilot of the IMHOTEP study.
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Kraus SM, Samuels P, Jermy S, Laing N, Van der Wall M, September U, Ntsekhe M, Chin A, Moosa S, Sliwa K, and Ntusi NAB
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- Adult, Humans, Female, Young Adult, Middle Aged, South Africa epidemiology, Pilot Projects, Magnetic Resonance Imaging, Cine methods, Gadolinium, Magnetic Resonance Spectroscopy, Predictive Value of Tests, Contrast Media, Cardiomyopathies diagnostic imaging, Cardiomyopathies epidemiology
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Background: Cardiomyopathy is an important cause of heart failure, however, there is notable lack of data on causes and manifestations of cardiomyopathy in Africa., Aims: The African Cardiomyopathy and Myocarditis Registry Program (IMHOTEP) aims to address the knowledge gap on etiology, treatment, and outcomes of cardiomyopathy in sub-Saharan Africa., Methods and Results: We conducted a single-center pilot study to delineate the clinical and cardiovascular magnetic resonance (CMR) phenotypes of cardiomyopathy in South African patients. Assessment of the first 99 adult incident cases [mean age 36.8 ± 12.5 years; females 53.5%] enrolled in IMHOTEP showed that dilated cardiomyopathy (n = 77) was commonest, followed by hypertrophic (n = 13), restrictive (n = 5) and arrhythmogenic (n = 4) cardiomyopathies. A broad range of etiologies were encountered with secondary causes identified in 42% of patients. Onset of symptoms in the peripartum period was observed in 47% of women, and peripartum cardiomyopathy was diagnosed in 32.1% of women recruited. In addition to electrocardiography and echocardiography, CMR was performed in 67 cases and contributed diagnostically in a third of cases. Acute inflammation was rarely observed [2%] on CMR, however, late gadolinium enhancement (LGE) was noted in 92% of cases., Conclusion: We report a diverse spectrum of causes of cardiomyopathy in the South African population, with secondary, potentially treatable, etiologies in a significant proportion of cases. CMR was useful in delineating specific phenotypes and etiologies, influencing clinical care. A higher-than-expected burden of LGE was observed in this young patient cohort - the implications of which are yet to be determined., Competing Interests: Declaration of competing interest The authors have no conflicts of interest to declare., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)
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- 2024
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27. Associations of HIV and prevalent type 2 diabetes mellitus in the context of obesity in South Africa.
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Magodoro IM, Castle AC, Tshuma N, Goedecke JH, Sewpaul R, Manasa J, Manne-Goehler J, Ntusi N, Nyirenda MJ, and Siedner MJ
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It is unclear how rising obesity among people with HIV (PWH) in sub-Saharan Africa (SSA) impacts their risk of type 2 diabetes mellitus (diabetes). Using a South African national cross-sectional sample of adult PWH and their peers without HIV (PWOH), we examined the associations between HIV and prevalent diabetes across the spectrum of body mass index (BMI), waist circumference (WC) and waist-to-height ratio (WtHR). Analyses were sex stratified, and adjusted for age, sociodemographic and behavioral factors. The prevalence of diabetes among males was similar between PWH and PWOH, overall and at all levels of adiposity. In contrast, overall diabetes prevalence was higher among female PWOH than female PWH. However, there were differences according to adiposity such that, compared to female PWOH, relative diabetes prevalence in female PWH was reduced with obesity but accentuated with leanness. These differences in the relationship between adiposity and diabetes by HIV serostatus call for better mechanistic understanding of sex-specific adipose tissue biology in HIV in South Africa, and possibly in other HIV endemic settings in SSA.
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- 2024
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28. Are Recommendations That Favor Other Agents Over Angiotensin-Converting Enzyme Inhibitors in Africans With Hypertension Justified?
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Peter JG, Ntusi NAB, and Ntsekhe M
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- Humans, Risk Factors, Angiotensin-Converting Enzyme Inhibitors therapeutic use, Hypertension drug therapy, Hypertension epidemiology
- Abstract
Competing Interests: Disclosures None.
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- 2024
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29. Post-pandemic memory T cell response to SARS-CoV-2 is durable, broadly targeted, and cross-reactive to the hypermutated BA.2.86 variant.
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Nesamari R, Omondi MA, Baguma R, Höft MA, Ngomti A, Nkayi AA, Besethi AS, Magugu SFJ, Mosala P, Walters A, Clark GM, Mennen M, Skelem S, Adriaanse M, Grifoni A, Sette A, Keeton RS, Ntusi NAB, Riou C, and Burgers WA
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- Humans, Memory T Cells, Pandemics, Spike Glycoprotein, Coronavirus genetics, SARS-CoV-2 genetics, COVID-19
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Ongoing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) evolution has given rise to recombinant Omicron lineages that dominate globally (XBB.1), as well as the emergence of hypermutated variants (BA.2.86). In this context, durable and cross-reactive T cell immune memory is critical for continued protection against severe COVID-19. We examined T cell responses to SARS-CoV-2 approximately 1.5 years since Omicron first emerged. We describe sustained CD4+ and CD8+ spike-specific T cell memory responses in healthcare workers in South Africa (n = 39) who were vaccinated and experienced at least one SARS-CoV-2 infection. Spike-specific T cells are highly cross-reactive with all Omicron variants tested, including BA.2.86. Abundant nucleocapsid and membrane-specific T cells are detectable in most participants. The bulk of SARS-CoV-2-specific T cell responses have an early-differentiated phenotype, explaining their persistent nature. Overall, hybrid immunity leads to the accumulation of spike and non-spike T cells evident 3.5 years after the start of the pandemic, with preserved recognition of highly mutated SARS-CoV-2 variants., Competing Interests: Declaration of interests A.S. is a consultant for AstraZeneca Pharmaceuticals, Calyptus Pharmaceuticals Inc, Darwin Health, EmerVax, EUROIMMUN, F. Hoffman-La Roche Ltd, Fortress Biotech, Gilead Sciences, Granite bio., Gritstone Oncology, Guggenheim Securities, Moderna, Pfizer, RiverVest Venture Partners, and Turnstone Biologics. A.G. is a consultant for Pfizer. L.J.I. has filed for patent protection for various aspects of T cell epitope and vaccine design work., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)
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- 2024
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30. The Determinants of Elevated Pathobiological Determination of Atherosclerosis in Youth Risk Score in Perinatally HIV-Infected Adolescents in South Africa.
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Mahtab S, Frigati LJ, Ntusi NAB, Nyathi M, Asafu-Agyei NA, Myer L, Zar HJ, and Jao J
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- Humans, Male, Adolescent, South Africa epidemiology, Viremia drug therapy, Risk Factors, Anti-Retroviral Agents therapeutic use, HIV Infections complications, HIV Infections drug therapy, Atherosclerosis epidemiology
- Abstract
Background: Youth living with perinatally acquired HIV infection (YLPHIV) are at risk of developing atherosclerotic cardiovascular disease., Methods: We determined the Pathobiological Determinants of Atherosclerosis in Youth (PDAY) coronary arteries (CA) and abdominal aorta (AA) risk scores among YLPHIV who are ≥15 years old in Cape Town Adolescent and Antiretroviral Cohort. PDAY score was calculated using non-high-density lipoprotein, high-density lipoprotein cholesterol, hyperglycemia, hypertension, obesity, and smoking; a score ≥1 was considered elevated. HIV viremia was categorized as sustained (SV) = viral load (VL) >50 copies/mL, transient (TV) = mix of VL >50 and ≤50 copies/mL, or sustained-virologic suppression = VL <50 copies/mL throughout the study. Among YLPHIV, logistic models were fit to assess factors associated with elevated PDAY., Results: Overall, 218 YLPHIV [median age 16.8 (interquartile range: 15.9-17.8) years, male 47%] were included. Among YLPHIV, 8% (n = 17) had SV, and 54% (n = 118) had TV. Median antiretroviral therapy (ART) duration was 12 (interquartile range: 8-14) years. Among YLPHIV, 30.3% and 18.4% had elevated PDAY for CA and AA, respectively.Among YLPHIV, SV [adjusted odds ratio (aOR) = 18.4, P < 0.01] and TV (aOR = 2.10, P = 0.04) compared with virologic suppression and ART duration in years (aOR = 1.12, P = 0.03) were associated with elevated CA. Male sex was associated with both elevated CA and AA (aOR = 2.14, P = 0.02, and aOR = 3.43, P = 0.01, respectively) and association of SV with elevated AA (aOR = 3.24, P = 0.09)., Conclusions: A substantial proportion of YLPHIV have PDAY scores reflecting increased aggregate atherosclerotic risk. Among YLPHIV, viremia, lifetime ART duration, and male sex contribute to this risk, highlighting the importance of HIV control and the need to monitor cardiometabolic health., Competing Interests: The authors have no funding or conflicts of interest to disclose., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)
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- 2024
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31. Changing character and waning impact of COVID-19 at a tertiary centre in Cape Town, South Africa.
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Hermans LE, Booysen P, Boloko L, Adriaanse M, de Wet TJ, Lifson AR, Wadee N, Papavarnavas N, Marais G, Hsiao NY, Rosslee MJ, Symons G, Calligaro GL, Iranzadeh A, Wilkinson RJ, Ntusi NAB, Williamson C, Davies MA, Meintjes G, and Wasserman S
- Abstract
Background: The emergence of genetic variants of SARS-CoV-2 was associated with changing epidemiological characteristics throughout coronavirus disease 2019 (COVID-19) pandemic in population-based studies. Individual-level data on the clinical characteristics of infection with different SARS-CoV-2 variants in African countries is less well documented., Objectives: To describe the evolving clinical differences observed with the various SARS-CoV-2 variants of concern and compare the Omicron-driven wave in infections to the previous Delta-driven wave., Method: We performed a retrospective observational cohort study among patients admitted to a South African referral hospital with COVID-19 pneumonia. Patients were stratified by epidemiological wave period, and in a subset, the variants associated with each wave were confirmed by genomic sequencing. Outcomes were analysed by Cox proportional hazard models., Results: We included 1689 patients were included, representing infection waves driven predominantly by ancestral, Beta, Delta and Omicron BA1/BA2 & BA4/BA5 variants. Crude 28-day mortality was 25.8% (34/133) in the Omicron wave period versus 37.1% (138/374) in the Delta wave period (hazard ratio [HR] 0.68 [95% CI 0.47-1.00] p = 0.049); this effect persisted after adjustment for age, gender, HIV status and presence of cardiovascular disease (adjusted HR [aHR] 0.43 [95% CI 0.28-0.67] p < 0.001). Hospital-wide SARS-CoV-2 admissions and deaths were highest during the Delta wave period, with a decoupling of SARS-CoV-2 deaths and overall deaths thereafter., Conclusion: There was lower in-hospital mortality during Omicron-driven waves compared with the prior Delta wave, despite patients admitted during the Omicron wave being at higher risk., Contribution: This study summarises clinical characteristics associated with SARS-CoV-2 variants during the COVID-19 pandemic at a South African tertiary hospital, demonstrating a waning impact of COVID-19 on healthcare services over time despite epidemic waves driven by new variants. Findings suggest the absence of increasing virulence from later variants and protection from population and individual-level immunity., Competing Interests: The authors have declared that no competing interest exists., (© 2023. The Authors.)
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- 2023
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32. Distinct T cell polyfunctional profile in SARS-CoV-2 seronegative children associated with endemic human coronavirus cross-reactivity.
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Benede N, Tincho MB, Walters A, Subbiah V, Ngomti A, Baguma R, Butters C, Hahnle L, Mennen M, Skelem S, Adriaanse M, Facey-Thomas H, Scott C, Day J, Spracklen TF, van Graan S, Balla SR, Moyo-Gwete T, Moore PL, MacGinty R, Botha M, Workman L, Johnson M, Goldblatt D, Zar HJ, Ntusi NAB, Zühlke L, Webb K, Riou C, Burgers WA, and Keeton RS
- Abstract
SARS-CoV-2 infection in children typically results in asymptomatic or mild disease. There is a paucity of studies on SARS-CoV-2 antiviral immunity in African children. We investigated SARS-CoV-2-specific T cell responses in 71 unvaccinated asymptomatic South African children who were seropositive or seronegative for SARS-CoV-2. SARS-CoV-2-specific CD4
+ T cell responses were detectable in 83% of seropositive and 60% of seronegative children. Although the magnitude of the CD4+ T cell response did not differ significantly between the two groups, their functional profiles were distinct, with SARS-CoV-2 seropositive children exhibiting a higher proportion of polyfunctional T cells compared to their seronegative counterparts. The frequency of SARS-CoV-2-specific CD4+ T cells in seronegative children was associated with the endemic human coronavirus (HCoV) HKU1 IgG response. Overall, the presence of SARS-CoV-2-responding T cells in seronegative children may result from cross-reactivity to endemic coronaviruses and could contribute to the relative protection from disease observed in SARS-CoV-2-infected children., Competing Interests: The authors have no competing interests., (© 2023 The Authors.)- Published
- 2023
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33. Myocardial extracellular volume fraction is positively associated with activated monocyte subsets among cART-treated persons living with HIV in South Africa.
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Peterson TE, Shey M, Masina N, Wong LY, Shuldiner SR, Wolfson J, Jermy S, Saad H, Lumbamba MAJ, Singh A, Meintjes G, Ntusi NAB, Ntsekhe M, and Baker JV
- Subjects
- Humans, Female, Middle Aged, Male, Contrast Media, South Africa epidemiology, Monocytes pathology, Gadolinium, Myocardium pathology, Fibrosis, Inflammation pathology, Magnetic Resonance Imaging, Cine, Cardiomyopathies, HIV Infections diagnosis, HIV Infections drug therapy, HIV Infections epidemiology
- Abstract
Background: Despite treatment with combination antiretroviral therapy (cART), persons living with HIV (PLWH) are at higher risk of cardiac structural abnormalities that may presage clinical heart failure, including myocardial fibrosis. This study assessed whether circulating cellular and soluble protein markers of immune activation cross-sectionally associate with myocardial fibrosis among cART-treated PLWH in South Africa., Methods: Participants were enrolled in Khayelitsha township near Cape Town, SA. Cardiac magnetic resonance imaging was performed. Plasma protein biomarkers were measured using enzyme-linked immunoassays and monocyte phenotypes were evaluated using flow cytometry. Associations were assessed using multivariable linear and logistic regression., Results: Among 69 cART-treated PLWH, mean (SD) age was 48 (10) years, 71% were female, and time since HIV diagnosis was 9 (6) years. Evidence of left ventricular fibrosis by late gadolinium enhancement was present in 74% of participants and mean (SD) extracellular volume fraction (ECV) was 30.9 (5.9)%. Degree of myocardial fibrosis/inflammation measured by ECV was positively associated with percentages of circulating non-classical and intermediate monocyte phenotypes reflecting inflammation and tissue injury., Conclusion: These data generate hypotheses on possible immune mechanisms of HIV-associated non-ischemic myocardial disease, specifically among cART-treated PLWH in sub-Saharan Africa, where the majority of the HIV burden exists globally., Competing Interests: Declaration of Competing Interest None., (Copyright © 2023 Elsevier B.V. All rights reserved.)
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- 2023
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34. Homologous Ad26.COV2.S vaccination results in reduced boosting of humoral responses in hybrid immunity, but elicits antibodies of similar magnitude regardless of prior infection.
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Moyo-Gwete T, Richardson SI, Keeton R, Hermanus T, Spencer H, Manamela NP, Ayres F, Makhado Z, Motlou T, Tincho MB, Benede N, Ngomti A, Baguma R, Chauke MV, Mennen M, Adriaanse M, Skelem S, Goga A, Garrett N, Bekker LG, Gray G, Ntusi NAB, Riou C, Burgers WA, and Moore PL
- Subjects
- Humans, SARS-CoV-2, Antibodies, Vaccination, Adaptive Immunity, Antibodies, Viral, Antibodies, Neutralizing, Immunity, Humoral, Ad26COVS1, COVID-19 prevention & control
- Abstract
The impact of previous SARS-CoV-2 infection on the durability of Ad26.COV2.S vaccine-elicited responses, and the effect of homologous boosting has not been well explored. We followed a cohort of healthcare workers for 6 months after receiving the Ad26.COV2.S vaccine and a further one month after they received an Ad26.COV2.S booster dose. We assessed longitudinal spike-specific antibody and T cell responses in individuals who had never had SARS-CoV-2 infection, compared to those who were infected with either the D614G or Beta variants prior to vaccination. Antibody and T cell responses elicited by the primary dose were durable against several variants of concern over the 6 month follow-up period, regardless of infection history. However, at 6 months after first vaccination, antibody binding, neutralization and ADCC were as much as 59-fold higher in individuals with hybrid immunity compared to those with no prior infection. Antibody cross-reactivity profiles of the previously infected groups were similar at 6 months, unlike at earlier time points, suggesting that the effect of immune imprinting diminishes by 6 months. Importantly, an Ad26.COV2.S booster dose increased the magnitude of the antibody response in individuals with no prior infection to similar levels as those with previous infection. The magnitude of spike T cell responses and proportion of T cell responders remained stable after homologous boosting, concomitant with a significant increase in long-lived early differentiated CD4 memory T cells. Thus, these data highlight that multiple antigen exposures, whether through infection and vaccination or vaccination alone, result in similar boosts after Ad26.COV2.S vaccination., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2023 Moyo-Gwete et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)
- Published
- 2023
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35. Simulating Subject-Specific Aortic Hemodynamic Effects of Valvular Lesions in Rheumatic Heart Disease.
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Cebull HL, Aremu OO, Kulkarni RS, Zhang SX, Samuels P, Jermy S, Ntusi NAB, and Goergen CJ
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- Humans, Aorta physiology, Aortic Valve diagnostic imaging, Magnetic Resonance Imaging, Hemodynamics physiology, Blood Flow Velocity physiology, Rheumatic Heart Disease diagnostic imaging
- Abstract
Rheumatic heart disease (RHD) is a neglected tropical disease despite the substantial global health burden. In this study, we aimed to develop a lower cost method of modeling aortic blood flow using subject-specific velocity profiles, aiding our understanding of RHD's consequences on the structure and function of the ascending aorta. Echocardiography and cardiovascular magnetic resonance (CMR) are often used for diagnosis, including valve dysfunction assessments. However, there is a need to further characterize aortic valve lesions to improve treatment options and timing for patients, while using accessible and affordable imaging strategies. Here, we simulated effects of RHD aortic valve lesions on the aorta using computational fluid dynamics (CFD). We hypothesized that inlet velocity distribution and wall shear stress (WSS) will differ between RHD and non-RHD individuals, as well as between subject-specific and standard Womersley velocity profiles. Phase-contrast CMR data from South Africa of six RHD subjects with aortic stenosis and/or regurgitation and six matched controls were used to estimate subject-specific velocity inlet profiles and the mean velocity for Womersley profiles. Our findings were twofold. First, we found WSS in subject-specific RHD was significantly higher (p < 0.05) than control subject simulations, while Womersley simulation groups did not differ. Second, evaluating spatial velocity differences (ΔSV) between simulation types revealed that simulations of RHD had significantly higher ΔSV than non-RHD (p < 0.05), these results highlight the need for implementing subject-specific input into RHD CFD, which we demonstrate how to accomplish through accessible methods., (Copyright © 2023 by ASME.)
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- 2023
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36. Comparing Cardiovascular Outcomes and Costs of Perindopril-, Enalapril- or Losartan-Based Antihypertensive Regimens in South Africa: Real-World Medical Claims Database Analysis.
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Snyman JR, Gumedze F, Jones ESW, Alaba OA, Tsabedze N, Vira A, and Ntusi NAB
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- Humans, Antihypertensive Agents therapeutic use, Enalapril therapeutic use, Enalapril pharmacology, Perindopril therapeutic use, South Africa epidemiology, Angiotensin-Converting Enzyme Inhibitors therapeutic use, Angiotensin-Converting Enzyme Inhibitors pharmacology, Blood Pressure, Losartan therapeutic use, Losartan pharmacology, Hypertension complications
- Abstract
Introduction: Differences in class or molecule-specific effects between renin-angiotensin-aldosterone system (RAAS) inhibitors have not been conclusively demonstrated. This study used South African data to assess clinical and cost outcomes of antihypertensive therapy with the three most common RAAS inhibitors: perindopril, losartan and enalapril., Methods: Using a large, South African private health insurance claims database, we identified patients with a hypertension diagnosis in January 2015 receiving standard doses of perindopril, enalapril or losartan, alone or in combination with other agents. From claims over the subsequent 5 years, we calculated the risk-adjusted rate of the composite primary outcome of myocardial infarction, ischaemic heart disease, heart failure or stroke; rate of all-cause mortality; and costs per life per month (PLPM), with adjustments based on demographic characteristics, healthcare plan and comorbidity., Results: Overall, 32,857 individuals received perindopril, 16,693 losartan and 13,939 enalapril. Perindopril-based regimens were associated with a significantly lower primary outcome rate (205 per 1000 patients over 5 years) versus losartan (221; P < 0.0001) or enalapril (223; P < 0.0001). The risk-adjusted all-cause mortality rate was lower with perindopril than enalapril (100 vs. 139 deaths per 1000 patients over 5 years; P = 0.007), but not losartan (100 vs. 94; P = 0.650). Mean (95% confidence interval) overall risk-adjusted cost PLPM was Rands (ZAR) 1342 (87-8973) for perindopril, ZAR 1466 (104-9365) for losartan (P = 0.0044) and ZAR 1540 (77-10,546) for enalapril (P = 0.0003)., Conclusion: In South African individuals with private health insurance, a perindopril-based antihypertensive regimen provided better clinical and cost outcomes compared with other regimens., (© 2023. The Author(s).)
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- 2023
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37. Left ventricular remodeling and its correlates among adolescents with perinatally acquired HIV in South Africa.
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Magodoro IM, Guerrero-Chalela CE, Claggett B, Jermy S, Samuels P, Zar H, Myer L, Danaei G, Jao J, Ntusi NAB, Siedner MJ, and Ntsekhe M
- Subjects
- Humans, Male, Adolescent, Female, South Africa epidemiology, Ventricular Remodeling, Cross-Sectional Studies, Anti-Retroviral Agents, HIV Infections diagnosis, HIV Infections epidemiology
- Abstract
Background: Left ventricular (LV) remodeling and its transitions from compensatory adaptations to LV dysfunction have not been examined in adolescents with perinatally acquired HIV infection (PHIV). We used cardiovascular magnetic resonance (CMR) in a cross-sectional study to characterize PHIV-related progressive LV remodeling in adolescents in South Africa., Methods: Adolescents with PHIV on antiretroviral treatment and their HIV uninfected peers completed 3 T CMR examination. We defined LV remodeling by LV mass/volume (M/V) ratio, modelling progressive LV remodeling as increasing M/V ratio. Linear regression models were applied to estimate the correlates of progressive LV remodeling., Results: Overall, 71 adolescents with PHIV [mean age: 15.2 years; 54% male] and 36 HIV uninfected [15.1 years; 42% male] peers were enrolled. Adolescents with PHIV had lower mean LV M/V ratio (0.68 vs. 0.75 g/mL; p = 0.004) than HIV uninfected peers, without LV hypertrophy in either group. Among adolescents with PHIV, increasing M/V ratio was accompanied by increasing interstitial volume [adjusted mean change (AMC) per 0.1 g/mL M/V ratio: 1.75 mL, p < 0.001] with no change in global circumferential strain (GCS) [AMC per 0.1 g/mL M/V ratio: -0.21%, p = 0.48]. However, in HIV uninfected individuals, increasing M/V ratio was accompanied by increasing peak GCS [AMC per 0.1 g/mL M/V ratio: -1.25%, p = 0.039] with no change in interstitial volume (AMC per 0.1 g/mL M/V ratio: 1.16 mL, p = 0.32]., Conclusions: Successfully treated PHIV is associated with less severe LV remodeling in adolescence when compared to HIV uninfected controls. LV remodeling in PHIV is associated with disproportionate expansion of the non-contractile interstitium not accompanied by improved GCS., Competing Interests: Declaration of Competing Interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests. Itai M. Magodoro reports financial support was provided by National Institutes of Health. Itai M. Magodoro reports financial support was provided by AIDS Healthcare Foundation. Heather Zar reports financial support was provided by National Institutes of Health. Heather Zar reports financial support was provided by South African Medical Research Council. Mark J. Siedner reports financial support was provided by National Institutes of Health., (Copyright © 2023 Elsevier B.V. All rights reserved.)
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- 2023
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38. Infection pre-Ad26.COV2.S-vaccination primes greater class switching and reduced CXCR5 expression by SARS-CoV-2-specific memory B cells.
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Krause RGE, Moyo-Gwete T, Richardson SI, Makhado Z, Manamela NP, Hermanus T, Mkhize NN, Keeton R, Benede N, Mennen M, Skelem S, Karim F, Khan K, Riou C, Ntusi NAB, Goga A, Gray G, Hanekom W, Garrett N, Bekker LG, Groll A, Sigal A, Moore PL, Burgers WA, and Leslie A
- Abstract
Neutralizing antibodies strongly correlate with protection for COVID-19 vaccines, but the corresponding memory B cells that form to protect against future infection are relatively understudied. Here we examine the effect of prior SARS-CoV-2 infection on the magnitude and phenotype of the memory B cell response to single dose Johnson and Johnson (Ad26.COV2.S) vaccination in South African health care workers. Participants were either naïve to SARS-CoV-2 or had been infected before vaccination. SARS-CoV-2-specific memory B-cells expand in response to Ad26.COV2.S and are maintained for the study duration (84 days) in all individuals. However, prior infection is associated with a greater frequency of these cells, a significant reduction in expression of the germinal center chemokine receptor CXCR5, and increased class switching. These B cell features correlated with neutralization and antibody-dependent cytotoxicity (ADCC) activity, and with the frequency of SARS-CoV-2 specific circulating T follicular helper cells (cTfh). Vaccination-induced effective neutralization of the D614G variant in both infected and naïve participants but boosted neutralizing antibodies against the Beta and Omicron variants only in participants with prior infection. In addition, the SARS-CoV-2 specific CD8+ T cell response correlated with increased memory B cell expression of the lung-homing receptor CXCR3, which was sustained in the previously infected group. Finally, although vaccination achieved equivalent B cell activation regardless of infection history, it was negatively impacted by age. These data show that phenotyping the response to vaccination can provide insight into the impact of prior infection on memory B cell homing, CSM, cTfh, and neutralization activity. These data can provide early signals to inform studies of vaccine boosting, durability, and co-morbidities., (© 2023. Springer Nature Limited.)
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- 2023
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39. HIV is sexually untransmittable when viral load is undetectable.
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Bekker LG, Smith P, and Ntusi NAB
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- Humans, Viral Load, Sexual Behavior, HIV Infections drug therapy
- Abstract
Competing Interests: L-GB reports personal fees from Merck, ViiV Healthcare, and Gilead Sciences outside the submitted work. PS and NABN declare no competing interests.
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- 2023
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40. High-Throughput Metabolomics Applications in Pathogenesis and Diagnosis of Valvular Heart Disease.
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Mutithu DW, Kirwan JA, Adeola HA, Aremu OO, Lumngwena EN, Wiesner L, Skatulla S, Naidoo R, and Ntusi NAB
- Abstract
High-throughput metabolomics techniques are a useful tool to understand many disease conditions including cardiovascular disease such as valvular heart disease(s) (VHD). VHD involves damage to heart valves, mostly presenting as stenosis, regurgitation or prolapse and can be classified into degenerative, rheumatic, congenital, or prosthetic valve disease. Gaps remain in our understanding of the pathogenesis of the common VHD. It is now fitting to place into perspective the contribution of metabolomics in the mechanism of development, diagnosis, and prognosis of VHD. A structured search for metabolomics studies centred on human VHD was undertaken. Biomarkers associated with the pathogenesis of bicuspid aortic valve disease, mitral valve disease, rheumatic heart disease, and degenerative aortic valve stenosis are reviewed and discussed. In addition, metabolic biomarkers reported to prognosticate patient outcomes of post-valve repair or replacement are highlighted. Finally, we also review the pitfalls and limitations to consider when designing metabolomics studies, especially from a clinician's viewpoint. In the future, reliable and simple metabolic biomarker(s) may supplement the existing diagnostic tools in the early diagnosis of VHD., Competing Interests: The authors declare no conflict of interest., (Copyright: © 2023 The Author(s). Published by IMR Press.)
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- 2023
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41. The oral microbiome in the pathophysiology of cardiovascular disease.
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Tonelli A, Lumngwena EN, and Ntusi NAB
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- Animals, Humans, Dysbiosis complications, Cardiovascular Diseases prevention & control, Microbiota, Gastrointestinal Microbiome, Heart Failure complications
- Abstract
Despite advances in our understanding of the pathophysiology of many cardiovascular diseases (CVDs) and expansion of available therapies, the global burden of CVD-associated morbidity and mortality remains unacceptably high. Important gaps remain in our understanding of the mechanisms of CVD and determinants of disease progression. In the past decade, much research has been conducted on the human microbiome and its potential role in modulating CVD. With the advent of high-throughput technologies and multiomics analyses, the complex and dynamic relationship between the microbiota, their 'theatre of activity' and the host is gradually being elucidated. The relationship between the gut microbiome and CVD is well established. Much less is known about the role of disruption (dysbiosis) of the oral microbiome; however, interest in the field is growing, as is the body of literature from basic science and animal and human investigations. In this Review, we examine the link between the oral microbiome and CVD, specifically coronary artery disease, stroke, peripheral artery disease, heart failure, infective endocarditis and rheumatic heart disease. We discuss the various mechanisms by which oral dysbiosis contributes to CVD pathogenesis and potential strategies for prevention and treatment., (© 2023. Springer Nature Limited.)
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- 2023
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42. Distinct T cell functional profiles in SARS-CoV-2 seropositive and seronegative children associated with endemic human coronavirus cross-reactivity.
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Benede NSB, Tincho MB, Walters A, Subbiah V, Ngomti A, Baguma R, Butters C, Mennen M, Skelem S, Adriaanse M, van Graan S, Balla SR, Moyo-Gwete T, Moore PL, Botha M, Workman L, Zar HJ, Ntusi NAB, Zühlke L, Webb K, Riou C, Burgers WA, and Keeton RS
- Abstract
SARS-CoV-2 infection in children typically results in asymptomatic or mild disease. There is a paucity of studies on antiviral immunity in African children. We investigated SARS-CoV-2-specific T cell responses in 71 unvaccinated asymptomatic South African children who were seropositive or seronegative for SARS-CoV-2. SARS-CoV-2-specific CD4+ T cell responses were detectable in 83% of seropositive and 60% of seronegative children. Although the magnitude of the CD4+ T cell response did not differ significantly between the two groups, their functional profiles were distinct, with SARS-CoV-2 seropositive children exhibiting a higher proportion of polyfunctional T cells compared to their seronegative counterparts. The frequency of SARS-CoV-2-specific CD4+ T cells in seronegative children was associated with the endemic human coronavirus (HCoV) HKU1 IgG response. Overall, the presence of SARS-CoV-2-responding T cells in seronegative children may result from cross-reactivity to endemic coronaviruses and could contribute to the relative protection from disease observed in SARS-CoV-2-infected children., Competing Interests: DECLARATION OF INTERESTS The authors have no competing interests.
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- 2023
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43. Cardiovascular magnetic resonance for evaluation of cardiac involvement in COVID-19: recommendations by the Society for Cardiovascular Magnetic Resonance.
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Ferreira VM, Plein S, Wong TC, Tao Q, Raisi-Estabragh Z, Jain SS, Han Y, Ojha V, Bluemke DA, Hanneman K, Weinsaft J, Vidula MK, Ntusi NAB, Schulz-Menger J, and Kim J
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- Humans, Heart diagnostic imaging, Magnetic Resonance Spectroscopy, Myocarditis diagnostic imaging, Predictive Value of Tests, COVID-19 complications, Magnetic Resonance Imaging methods, Magnetic Resonance Imaging standards, Heart Diseases diagnostic imaging, Heart Diseases etiology
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Coronavirus disease 2019 (COVID-19) is an ongoing global pandemic that has affected nearly 600 million people to date across the world. While COVID-19 is primarily a respiratory illness, cardiac injury is also known to occur. Cardiovascular magnetic resonance (CMR) imaging is uniquely capable of characterizing myocardial tissue properties in-vivo, enabling insights into the pattern and degree of cardiac injury. The reported prevalence of myocardial involvement identified by CMR in the context of COVID-19 infection among previously hospitalized patients ranges from 26 to 60%. Variations in the reported prevalence of myocardial involvement may result from differing patient populations (e.g. differences in severity of illness) and the varying intervals between acute infection and CMR evaluation. Standardized methodologies in image acquisition, analysis, interpretation, and reporting of CMR abnormalities across would likely improve concordance between studies. This consensus document by the Society for Cardiovascular Magnetic Resonance (SCMR) provides recommendations on CMR imaging and reporting metrics towards the goal of improved standardization and uniform data acquisition and analytic approaches when performing CMR in patients with COVID-19 infection., (© 2023. The Author(s).)
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- 2023
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44. Sex modulates the association between inflammation and coronary atherosclerosis among older Ugandan adults with and without HIV.
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Shakil SS, Temu TM, Kityo C, Nazzinda R, Erem G, Kentoffio K, Bittencourt M, Ntusi NAB, Zanni MV, and Longenecker CT
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- Female, Humans, Male, Middle Aged, Biomarkers, Coronary Angiography, Inflammation complications, Lipopolysaccharide Receptors, Prospective Studies, Risk Factors, Tumor Necrosis Factor-alpha, Uganda, Coronary Artery Disease complications, HIV Infections complications
- Abstract
Objective: Inflammation is key in the pathogenesis of atherosclerotic coronary artery disease (CAD). Distinct sex-specific inflammatory mechanisms may contribute to CAD in sub-Saharan Africa (SSA), where environmental and biological determinants of systemic inflammation may differ from those in high-income settings., Approach and Results: We investigated sex differences in inflammatory markers and CAD in a 2-year prospective cohort of Ugandan adults enriched for cardiometabolic risk factors (RFs) and HIV. Seven plasma biomarkers were quantified at the baseline visit among 125 females and 75 males (50% with HIV) at least 45 years old at enrollment with one or more major cardiovascular RF. In year 2, coronary CT angiography (CCTA) was performed in 82 females and 50 males returning for follow-up (52% with HIV). In sex-specific models adjusted for cardiovascular RFs and HIV, tumor necrosis factor-alpha (TNF-α) RII and sCD163 predicted subsequent CAD in females, while only fibrinogen was predictive in males ( P < 0.05). Interleukin-6 (IL-6) and sCD14 were inversely associated with CAD in males ( P < 0.05). Sex modified the associations of TNF-α RII, sCD14, and sCD163 with CAD ( P < 0.05 for interaction). In multivariable multiple imputation models applied to missing year 2 CCTA data to test associations between serum biomarkers in the baseline cohort ( n = 200) and subsequent CAD, higher sCD163 was predictive in females only ( P < 0.05)., Conclusions: The positive link between inflammation and subclinical CAD was stronger among females than males in Uganda. Mechanisms by which sex modulates the relationship between inflammation and CAD should be further investigated in SSA., (Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.)
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- 2023
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45. Epitope Coverage of Anti-SARS-CoV-2 Nucleocapsid IgA and IgG Antibodies Correlates with Protection against Re-Infection by New Variants in Subsequent Waves of the COVID-19 Pandemic.
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Mullins MO, Smith M, Maboreke H, Nel AJM, Ntusi NAB, Burgers WA, and Blackburn JM
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- Humans, Epitopes, Immunoglobulin G, Pandemics, Nucleocapsid, Reinfection, Immunoglobulin A, SARS-CoV-2, COVID-19 epidemiology
- Abstract
The COVID-19 pandemic continues to affect individuals across the globe, with some individuals experiencing more severe disease than others. The relatively high frequency of re-infections and breakthrough infections observed with SARS-CoV-2 highlights the importance of extending our understanding of immunity to COVID-19. Here, we aim to shed light on the importance of antibody titres and epitope utilization in protection from re-infection. Health care workers are highly exposed to SARS-CoV-2 and are therefore also more likely to become re-infected. We utilized quantitative, multi-antigen, multi-epitope SARS-CoV-2 protein microarrays to measure IgG and IgA titres against various domains of the nucleocapsid and spike proteins. Potential re-infections in a large, diverse health care worker cohort (N = 300) during the second wave of the pandemic were identified by assessing the IgG anti-N titres before and after the second wave. We assessed epitope coverage and antibody titres between the 'single infection' and 're-infection' groups. Clear differences were observed in the breadth of the anti-N response before the second wave, with the epitope coverage for both IgG ( p = 0.019) and IgA ( p = 0.015) being significantly increased in those who did not become re-infected compared to those who did. Additionally, the IgG anti-N ( p = 0.004) and anti-S titres ( p = 0.018) were significantly higher in those not re-infected. These results highlight the importance of the breadth of elicited antibody epitope coverage following natural infection in protection from re-infection and disease in the COVID-19 pandemic.
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- 2023
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46. Outcomes of laboratory-confirmed SARS-CoV-2 infection during resurgence driven by Omicron lineages BA.4 and BA.5 compared with previous waves in the Western Cape Province, South Africa.
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Davies MA, Morden E, Rousseau P, Arendse J, Bam JL, Boloko L, Cloete K, Cohen C, Chetty N, Dane P, Heekes A, Hsiao NY, Hunter M, Hussey H, Jacobs T, Jassat W, Kariem S, Kassanjee R, Laenen I, Roux SL, Lessells R, Mahomed H, Maughan D, Meintjes G, Mendelson M, Mnguni A, Moodley M, Murie K, Naude J, Ntusi NAB, Paleker M, Parker A, Pienaar D, Preiser W, Prozesky H, Raubenheimer P, Rossouw L, Schrueder N, Smith B, Smith M, Solomon W, Symons G, Taljaard J, Wasserman S, Wilkinson RJ, Wolmarans M, Wolter N, and Boulle A
- Subjects
- Humans, SARS-CoV-2, South Africa epidemiology, Hospitalization, Laboratories, COVID-19 diagnosis, COVID-19 epidemiology
- Abstract
Objectives: We aimed to compare the clinical severity of Omicron BA.4/BA.5 infection with BA.1 and earlier variant infections among laboratory-confirmed SARS-CoV-2 cases in the Western Cape, South Africa, using timing of infection to infer the lineage/variant causing infection., Methods: We included public sector patients aged ≥20 years with laboratory-confirmed COVID-19 between May 01-May 21, 2022 (BA.4/BA.5 wave) and equivalent previous wave periods. We compared the risk between waves of (i) death and (ii) severe hospitalization/death (all within 21 days of diagnosis) using Cox regression adjusted for demographics, comorbidities, admission pressure, vaccination, and previous infection., Results: Among 3793 patients from the BA.4/BA.5 wave and 190,836 patients from previous waves, the risk of severe hospitalization/death was similar in the BA.4/BA.5 and BA.1 waves (adjusted hazard ratio [aHR] 1.12; 95% confidence interval [CI] 0.93; 1.34). Both Omicron waves had a lower risk of severe outcomes than previous waves. Previous infection (aHR 0.29, 95% CI 0.24; 0.36) and vaccination (aHR 0.17; 95% CI 0.07; 0.40 for at least three doses vs no vaccine) were protective., Conclusion: Disease severity was similar among diagnosed COVID-19 cases in the BA.4/BA.5 and BA.1 periods in the context of growing immunity against SARS-CoV-2 due to previous infection and vaccination, both of which were strongly protective., (Copyright © 2022 The Author(s). Published by Elsevier Ltd.. All rights reserved.)
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- 2023
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47. Antibody-dependent cellular cytotoxicity against SARS-CoV-2 Omicron sub-lineages is reduced in convalescent sera regardless of infecting variant.
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Richardson SI, Kgagudi P, Manamela NP, Kaldine H, Venter EM, Pillay T, Lambson BE, van der Mescht MA, Hermanus T, Balla SR, de Beer Z, de Villiers TR, Bodenstein A, van den Berg G, du Pisanie M, Burgers WA, Ntusi NAB, Abdullah F, Ueckermann V, Rossouw TM, Boswell MT, and Moore PL
- Subjects
- Humans, Antibodies, Breakthrough Infections, COVID-19 immunology, COVID-19 therapy, Antibody-Dependent Cell Cytotoxicity, COVID-19 Serotherapy, SARS-CoV-2 immunology
- Abstract
The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron BA.4 and BA.5 variants caused major waves of infections. Here, we assess the sensitivity of BA.4 to binding, neutralization, and antibody-dependent cellular cytotoxicity (ADCC) potential, measured by FcγRIIIa signaling, in convalescent donors infected with four previous variants of SARS-CoV-2, as well as in post-vaccination breakthrough infections (BTIs) caused by Delta or BA.1. We confirm that BA.4 shows high-level neutralization resistance regardless of the infecting variant. However, BTIs retain activity against BA.4, albeit at reduced titers. BA.4 sensitivity to ADCC is reduced compared with other variants but with smaller fold losses compared with neutralization and similar patterns of cross-reactivity. Overall, the high neutralization resistance of BA.4, even to antibodies from BA.1 infection, provides an immunological mechanism for the rapid spread of BA.4 immediately after a BA.1-dominated wave. Furthermore, although ADCC potential against BA.4 is reduced, residual activity may contribute to observed protection from severe disease., Competing Interests: Declaration of interests P.L.M. is a member of the advisory board for Cell Reports Medicine., (Copyright © 2022 The Author(s). Published by Elsevier Inc. All rights reserved.)
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- 2023
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48. Impact of SARS-CoV-2 exposure history on the T cell and IgG response.
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Keeton R, Tincho MB, Suzuki A, Benede N, Ngomti A, Baguma R, Chauke MV, Mennen M, Skelem S, Adriaanse M, Grifoni A, Weiskopf D, Sette A, Bekker LG, Gray G, Ntusi NAB, Burgers WA, and Riou C
- Subjects
- Humans, Antibody Formation, CD4-Positive T-Lymphocytes, SARS-CoV-2, COVID-19 epidemiology, Immunoglobulin G, T-Lymphocytes
- Abstract
Multiple severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) exposures, from infection or vaccination, can potently boost spike antibody responses. Less is known about the impact of repeated exposures on T cell responses. Here, we compare the prevalence and frequency of peripheral SARS-CoV-2-specific T cell and immunoglobulin G (IgG) responses in 190 individuals with complex SARS-CoV-2 exposure histories. As expected, an increasing number of SARS-CoV-2 spike exposures significantly enhances the magnitude of IgG responses, while repeated exposures improve the number of T cell responders but have less impact on SARS-CoV-2 spike-specific T cell frequencies in the circulation. Moreover, we find that the number and nature of exposures (rather than the order of infection and vaccination) shape the spike immune response, with spike-specific CD4 T cells displaying a greater polyfunctional potential following hybrid immunity compared with vaccination only. Characterizing adaptive immunity from an evolving viral and immunological landscape may inform vaccine strategies to elicit optimal immunity as the pandemic progress., Competing Interests: Declaration of interests A. Sette is a consultant for Gritstone Bio, Flow Pharma, Moderna, AstraZeneca, Qiagen, Avalia, Fortress, Gilead, Sanofi, Merck, RiverVest, MedaCorp, Turnstone, NA Vaccine Institute, Gerson Lehrman Group, and Guggenheim. La Jolla Institute for Immunology has filed for patent protection for various aspects of T cell epitope and vaccine design work., (Copyright © 2022 The Author(s). Published by Elsevier Inc. All rights reserved.)
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- 2023
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49. Effects of tuberculosis and/or HIV-1 infection on COVID-19 presentation and immune response in Africa.
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du Bruyn E, Stek C, Daroowala R, Said-Hartley Q, Hsiao M, Schafer G, Goliath RT, Abrahams F, Jackson A, Wasserman S, Allwood BW, Davis AG, Lai RP, Coussens AK, Wilkinson KA, de Vries J, Tiffin N, Cerrone M, Ntusi NAB, Riou C, and Wilkinson RJ
- Subjects
- Adult, Humans, Africa epidemiology, HIV-1, Immunity, SARS-CoV-2, COVID-19 complications, COVID-19 epidemiology, COVID-19 immunology, HIV Infections complications, HIV Infections epidemiology, Tuberculosis complications, Tuberculosis epidemiology
- Abstract
Few studies from Africa have described the clinical impact of co-infections on SARS-CoV-2 infection. Here, we investigate the presentation and outcome of SARS-CoV-2 infection in an African setting of high HIV-1 and tuberculosis prevalence by an observational case cohort of SARS-CoV-2 patients. A comparator group of non SARS-CoV-2 participants is included. The study includes 104 adults with SARS-CoV-2 infection of whom 29.8% are HIV-1 co-infected. Two or more co-morbidities are present in 57.7% of participants, including HIV-1 (30%) and active tuberculosis (14%). Amongst patients dually infected by tuberculosis and SARS-CoV-2, clinical features can be typical of either SARS-CoV-2 or tuberculosis: lymphopenia is exacerbated, and some markers of inflammation (D-dimer and ferritin) are further elevated (p < 0.05). Amongst HIV-1 co-infected participants those with low CD4 percentage strata exhibit reduced total, but not neutralising, anti-SARS-CoV-2 antibodies. SARS-CoV-2 specific CD8 T cell responses are present in 35.8% participants overall but undetectable in combined HIV-1 and tuberculosis. Death occurred in 30/104 (29%) of all COVID-19 patients and in 6/15 (40%) of patients with coincident SARS-CoV-2 and tuberculosis. This shows that in a high incidence setting, tuberculosis is a common co-morbidity in patients admitted to hospital with COVID-19. The immune response to SARS-CoV-2 is adversely affected by co-existent HIV-1 and tuberculosis., (© 2023. The Author(s).)
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- 2023
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50. Nutritional Heart Disease and Cardiomyopathies: JACC Focus Seminar 4/4.
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Sliwa K, Viljoen CA, Hasan B, and Ntusi NAB
- Abstract
This JACC Focus Seminar provides an overview of and highlights recently published research on cardiomyopathies and nutritional heart disease that have a higher prevalence in tropical regions. The development of tropical cardiomyopathies and nutritional cardiovascular disease (CVD) is complicated by high rates of poverty, fragmented health care systems, and suboptimal access to health care because of socioeconomic inequalities, leading to the fact that children, adolescents, and young adults are disproportionally affected. Such tropical cardiomyopathies and nutritional CVD that have not been prevalent in high-income countries in the past decades are now reemerging. When treating migrants or refugees, it is important for attending physicians to consider the burden of endemic diseases in the countries of origin and the likelihood that such patients might be affected. In this review, the authors propose an approach for adequate diagnostic work-up leading to appropriate care for those with suspected or confirmed tropical cardiomyopathies and nutritional CVD., Competing Interests: Funding Support and Author Disclosures Support for the Cape Heart Institute was provided by the following funding bodies: the University of Cape Town, the South African Medical Research Council, the National Research Foundation SA, and the Hippocrate Foundation. The authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2023 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)
- Published
- 2022
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