Search

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease. Clinical heterogeneity and complex genetics pose challenges to understanding disease mechanisms and producing effective cures. To model clinical heterogeneity, we generated human induced pluripotent stem cells (iPSCs) from two sporadic ALS patients (sporadic ALS and sporadic ALS with frontotemporal dementia), two familial ALS patients (familial SOD1 mutation positive and familial C9orf72 repeat expansion positive), and four age- and sex-matched healthy controls. These iPSCs can be used to generate 2D and 3D in vitro models of ALS to investigate mechanisms of disease and screen for therapeutics., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Timothy J Tracey reports financial support was provided by Motor Neurone Disease Research Australia. Shyuan T Ngo reports financial support was provided by National Health and Medical Research Council. Shyuan T Ngo reports financial support was provided by Motor Neurone Disease Research Australia. Shyuan T Ngo reports financial support was provided by FightMND. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Background and Objectives: Altered metabolism is observed in amyotrophic lateral sclerosis (ALS). However, without a standardized methodology to define metabolic changes, our understanding of factors contributing to and the clinical significance of altered metabolism in ALS is limited., Methods: We aimed to determine how geographic variation in metabolic rates influences estimates and accuracy of predicted resting energy expenditure (REE) in patients with ALS and controls, while validating the effectiveness of cohort-specific approaches in predicting altered metabolic rate in ALS. Participants from 3 geographically distinct sites across Australia, China, and the Netherlands underwent REE assessments, and we considered 22 unique equations for estimating REE. Analyses evaluated equation performance and the influence of demographics on metabolic status. Comparisons were made using standardized and local reference values to identify metabolic alterations., Results: 606 participants were included from Australia (patients with ALS: 140, controls: 154), the Netherlands (patients with ALS: 79, controls: 37) and China (patients with ALS: 67, controls: 129). Measured REE was variable across geographic cohorts, with fat-free mass contributing to this variation across all patients ( p = 0.002 to p < 0.001). Of the 22 predication equations assessed, the Sabounchi Structure 4 (S4) equation performed relatively well across all control cohorts. Use of prediction thresholds generated using data from Australian controls generally increased the prevalence of hypermetabolism in Chinese (55%, [43%-67%]) and Dutch (44%, [33%-55%]) cases when compared with Australian cases (30%, [22%-38%]). Adjustment of prediction thresholds to consider geographically distinct characteristics from matched control cohorts resulted in a decrease in the proportion of hypermetabolic cases in Chinese and Dutch cohorts (25%-31% vs 55% and 20%-34% vs 43%-44%, respectively), and increased prevalence of hypometabolism in Dutch cases with ALS (1% to 8%-10%)., Discussion: The identification of hypermetabolism in ALS is influenced by the formulae and demographic-specific prediction thresholds used for defining alterations in metabolic rate. A consensus approach is needed for identification of metabolic changes in ALS and will facilitate improved understanding of the cause and clinical significance of this in ALS.

Background and Purpose: Loss of appetite contributes to weight loss and faster disease progression in amyotrophic lateral sclerosis (ALS). Impairment of appetite control in ALS may include altered production or action of orexigenic (i.e., ghrelin) and anorexigenic (i.e., liver-expressed antimicrobial peptide 2 [LEAP2] and leptin) hormones. We aimed to determine if postprandial circulating ghrelin levels, LEAP2 levels, LEAP2:ghrelin molar ratio and leptin levels differ in ALS patients compared to non-neurodegenerative disease controls, and whether they are associated with disease progression and body composition., Methods: In this prospective natural history study, we assessed postprandial plasma levels of ghrelin, LEAP2 and leptin in patients with ALS (cases; n = 46) and controls (controls; n = 43). For cases, measures were compared to changes in body weight, body composition and clinical outcomes., Results: Postprandial ghrelin level was decreased by 52% in cases compared to controls (p = 0.013). LEAP2:ghrelin molar ratio was increased by 249% (p = 0.009), suggesting greater ghrelin resistance. Patients with lower LEAP2:ghrelin tended to have better functional capacity at assessment, as inferred by the ALS Functional Rating Scale-Revised (τ = -0.179, p = 0.086). Furthermore, ghrelin and LEAP2:ghrelin molar ratio correlated with diagnostic delay (ghrelin, τ = 0.223, p = 0.029; LEAP2:ghrelin, τ = -0.213, p = 0.037). Baseline ghrelin level, LEAP2 level, LEAP2:ghrelin ratio and leptin level were, however, not predictive of change in functional capacity during follow-up. Also, patients with higher postprandial ghrelin levels (hazard ratio [HR] 1.375, p = 0.048), and lower LEAP2:ghelin ratios (HR 0.828, p = 0.051) had an increased risk of earlier death., Conclusions: Reduced postprandial ghrelin levels, coupled with increased LEAP2:ghrelin molar ratios, suggests a loss of ghrelin action in patients with ALS. Given ghrelin's actions on appetite, metabolism and neuroprotection, reduced ghrelin and greater ghrelin resistance could contribute to impaired capacity to tolerate the physiological impact of disease. Comprehensive studies are needed to explain how ghrelin and LEAP2 contribute to body weight regulation and disease progression in ALS., (© 2023 The Authors. European Journal of Neurology published by John Wiley & Sons Ltd on behalf of European Academy of Neurology.)

Background and Purpose: To establish the utility of venous creatinine as a biomarker to monitor loss of fat-free mass in patients with amyotrophic lateral sclerosis (ALS)., Methods: In this multicenter natural history study, body composition and venous creatinine were assessed in 107 patients with ALS and 52 healthy controls. Longitudinal patterns of venous creatinine and its association with the risk of death during follow-up were determined in a cohort of patients with ALS from Australia (n = 69) and the Netherlands (n = 38)., Results: The mean levels of venous creatinine were 75.78 ± 11.15 μmol/L for controls, 70.25 ± 12.81 μmol/L for Australian patients, and 59.95 ± 14.62 μmol/L for Dutch patients with ALS. The relationship between measures of venous creatinine and fat-free mass was similar between all groups (r = 0.36, p < 0.001). Within patients, fat-free mass declined by 0.31 (95% confidence interval [CI]: 0.22-0.40) kg/month, and venous creatinine declined by 0.52 (95% CI: 0.38-0.66) μmol/L/month, with a longitudinal correlation of 0.57 (95% CI: 0.35-0.76, p < 0.001). Lower levels of venous creatinine were associated with increased risk for earlier death in patients with ALS (hazard ratio = 0.94, 95% CI: 0.90-0.98, p = 0.007)., Conclusions: Venous creatinine is decreased in ALS and declines alongside a decline in fat-free mass over the course of the disease, and may serve as a practical marker to monitor the change of fat-free mass in patients with ALS. This could inform clinical care and provide an alternative endpoint for the evaluation of therapeutic interventions that focus on slowing the loss of fat-free mass and disease progression in ALS., (© 2021 European Academy of Neurology.)

Background and Objective: Patients are required to support their cheeks during breath-occluding lung function tests. This prevents cheek expansion which would alter pressure measured at the mouth, and, consequently, lung mechanics measurements. To date, the effect of cheek support on airway resistance measurements has been assessed. However other lung mechanics have not been studied as thoroughly, and no algorithm to account for the effect of missing cheek support on lung mechanics measurements has been developed., Methods: Lung mechanics were assessed with a breath occlusion test during light panting in healthy subjects with and without cheek support in a body plethysmograph. Average model-based airway resistance, lung elastance, and a parameter representing the viscoelastic were measured. Results were compared to quantify the effect of cheek support on these three parameters., Results: In the nine healthy subjects (5 Female, 4 Male) recruited for this study, all mechanics tended to be underestimated when cheeks were unsupported. Changes in elastance, resistance, and viscoelastic parameter ranged between 1.6-66.8 %, -4.5-21.8 %, and -4.7-68.2 %, respectively, when cheek support was added. The underestimation was due to reduced mouth pressure during cheek expansion when the breath was occluded. The variance of lung mechanics parameters did not change with cheek support in all subjects., Conclusions: The error in lung mechanics measurement caused by unsupported cheeks was subject dependent. Hence, no rule-of-thumb could be identified to reconstruct missing cheek support. For correct lung mechanics measurements during breath-occluding lung tests, patients must have adequate cheek support., Abbreviations: ROCC: Occlusion resistance; COPD: Chronic Obstructive Pulmonary Disorder; SB: spontaneous breathing., Competing Interests: Declaration of Competing Interest The authors declare that they have no competing interests., (Copyright © 2020. Published by Elsevier B.V.)

Background and Objective: Lung mechanics measurements provide clinically useful information about disease progression and lung health. Currently, there are no commonly practiced methods to non-invasively measure both resistive and elastic lung mechanics during tidal breathing, preventing the important information provided by lung mechanics from being utilised. This study presents a novel method to easily assess lung mechanics of spontaneously breathing subjects using a dynamic elastance, single-compartment lung model., Methods: A spirometer with a built-in shutter was used to occlude expiration during tidal breathing, creating exponentially decaying flow when the shutter re-opened. The lung mechanics measured were respiratory system elastance and resistance, separated from the exponentially decaying flow, and interrupter resistance calculated at shutter closure. Progressively increasing resistance was added to the spirometer mouthpiece to simulate upper airway obstruction. The lung mechanics of 17 healthy subjects were successfully measured through spirometry., Results: N = 17 (8 female, 9 male) healthy subjects were recruited. Measured decay rates ranged from 5 to 42/s, subjects with large variation of decay rates showed higher muscular breathing effort. Lung elastance measurements ranged from 3.9 to 21.2 cmH[Formula: see text]O/L, with no clear trend between change in elastance and added resistance. Resistance calculated from decay rate and elastance ranged from 0.15 to 1.95 cmH[Formula: see text]Os/L. These very small resistance values are due to the airflow measured originating from low-resistance areas in the centre of airways. Occlusion resistance measurements were as expected for healthy subjects, and increased as expected as resistance was added., Conclusions: This test was able to identify reasonable dynamic lung elastance and occlusion resistance values, providing new insight into expiratory breathing effort. Clinically, this lung function test could impact current practice. It does not require high levels of cooperation from the subject, allowing a wider cohort of patients to be assessed more easily. Additionally, this test can be simply implemented in a small standalone device, or with standard lung function testing equipment.

Background and Objective: Model-based lung mechanics monitoring can provide clinically useful information for guiding mechanical ventilator treatment in intensive care. However, many methods of measuring lung mechanics are not appropriate for both fully and partially sedated patients, and are unable provide lung mechanics metrics in real-time. This study proposes a novel method of using lung mechanics identified during passive expiration to estimate inspiratory lung mechanics for spontaneously breathing patients., Methods: Relationships between inspiratory and expiratory modeled lung mechanics were identified from clinical data from 4 fully sedated patients. The validity of these relationships were assessed using data from a further 4 spontaneously breathing patients., Results: For the fully sedated patients, a linear relationship was identified between inspiratory and expiratory elastance, with slope 1.04 and intercept 1.66. The r value of this correlation was 0.94. No cohort-wide relationship was determined for airway resistance. Expiratory elastance measurements in spontaneously breathing patients were able to produce reasonable estimates of inspiratory elastance after adjusting for the identified difference between them., Conclusions: This study shows that when conventional methods fail, typically ignored expiratory data may be able to provide clinicians with the information needed about patient condition to guide MV therapy., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Mechanical ventilation (MV) is a core life-support therapy for patients suffering from respiratory failure or acute respiratory distress syndrome (ARDS). Respiratory failure is a secondary outcome of a range of injuries and diseases, and results in almost half of all intensive care unit (ICU) patients receiving some form of MV. Funding the increasing demand for ICU is a major issue and MV, in particular, can double the cost per day due to significant patient variability, over-sedation, and the large amount of clinician time required for patient management. Reducing cost in this area requires both a decrease in the average duration of MV by improving care, and a reduction in clinical workload. Both could be achieved by safely automating all or part of MV care via model-based dynamic systems modelling and control methods are ideally suited to address these problems. This paper presents common lung models, and provides a vision for a more automated future and explores predictive capacity of some current models. This vision includes the use of model-based methods to gain real-time insight to patient condition, improve safety through the forward prediction of outcomes to changes in MV, and develop virtual patients for in-silico design and testing of clinical protocols. Finally, the use of dynamic systems models and system identification to guide therapy for improved personalised control of oxygenation and MV therapy in the ICU will be considered. Such methods are a major part of the future of medicine, which includes greater personalisation and predictive capacity to both optimise care and reduce costs. This review thus presents the state of the art in how dynamic systems and control methods can be applied to transform this core area of ICU medicine., (© 2019 Elsevier Ltd. All rights reserved.)

Background and Objectives: Mechanical ventilation (MV) is a primary therapy for patients with acute respiratory failure. However, poorly selected ventilator settings can cause further lung damage due to heterogeneity of healthy and damaged alveoli. Varying positive-end-expiratory-pressure (PEEP) to a point of minimum elastance is a lung protective ventilator strategy. However, even low levels of PEEP can lead to ventilator induced lung injury for individuals with highly inflamed pulmonary tissue. Hence, models that could accurately predict peak inspiratory pressures after changes to PEEP could improve clinician confidence in attempting potentially beneficial treatment strategies., Methods: This study develops and validates a physiologically relevant respiratory model that captures elastance and resistance via basis functions within a well-validated single compartment lung model. The model can be personalised using information available at a low PEEP to predict lung mechanics at a higher PEEP. Proof of concept validation is undertaken with data from four patients and eight recruitment manoeuvre arms., Results: Results show low error when predicting upwards over the clinically relevant pressure range, with the model able to predict peak inspiratory pressure with less than 10% error over 90% of the range of PEEP changes up to 12 cmH 2 O., Conclusions: The results provide an in-silico model-based means of predicting clinically relevant responses to changes in MV therapy, which is the foundation of a first virtual patient for MV., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Cervical carcinoma is the most common cancer among Belizean women; however, data regarding the frequency of human papillomavirus (HPV) genotypes and their association with cervical cancer are nonexistent. We therefore included HPV genotyping as part of a week-long cervical cancer screening campaign conducted in Belize City in 2007. Conventional Papanicolaou smears with Hybrid Capture (HC) 2 HPV testing were performed on 463 women. All HC2-positive samples were genotyped using a developmental GP5+/GP6+ polymerase chain reaction-coupled Luminex assay for 2 low-risk and 18 high-risk HPV types. The prevalence of high-risk HPV was 15.6% in the total population, 10.1% in those with normal cytologic findings, and 93.3% in women with a high-grade squamous intraepithelial lesion. Of patients with HPV infections, 35% had multiple types (5.4% of the total group). Of all women and of women with normal cytologic findings, 5.2% and 2.8%, respectively, had HPV16 or 18. For all women, HPV16, 18, 56, and 52 were present in decreasing order of frequency. HPV11 was present in only one patient, and none had HPV6. HPV16 was found in 47% of high-grade squamous epithelial lesions; however, no case of HSIL had HPV18 or 45. HPV35 and HPV58 were the next most common types in high-grade squamous intraepithelial lesion, each occurring in 20% of cases of high-grade squamous intraepithelial lesion, followed by HPV31 in 13.3%. Although women younger than 25 years old were underrepresented, these data suggest that the HPV profile of this cohort of Belizean women differs somewhat from that in the region. In addition, these data are of importance with regard to the development of HPV vaccines that will be used in less developed countries, where care should be taken not to implement vaccination at the cost of basic screening and diagnostic services.

Background: Nicaragua has some of the highest rates of cervical cancer in Latin America and the world. In 2003, the Nicaraguan Ministry of Health, the Central American Institute of Health and the Maria Luisa Ortiz Clinic combined efforts to create an effective remote rural service network, with centralized quality-controlled cytology, and coordinated treatment., Methods and Materials: Data was taken from the clinic Pap log, tracking records, patient charts, and pathology reports. Patients were stratified by age (25 and older, and under 25). Standard indicators addressing key components in the entire continuum of an effective screening program were adapted from suggestions by a work group of the Pan American Health Organization., Results: A total of 2132 women received Pap screening. 68% (N = 1448) were 25 and older and 32% (N = 684) were under 25. The proportion of high-grade abnormal screens was 3.7% for women over 25 and 0.4% for women under 25. The proportion of women with high-grade abnormal results who received diagnostic work-up and needed treatment was 94% for women over 25 and 100% for women under 25. The proportion of high-grade squamous cell Pap tests resulting in histologically confirmed disease was 68%. The ratio of pre-invasive disease to invasive disease was 1.9. The invasive cancer detection rate was 0.62%., Conclusion: This program evaluation demonstrates that outreach to high-risk women, quality cytology screening and high rates of diagnostic follow-up and treatment can be conducted in remote, low-resource settings when coordinated efforts are made to remove barriers and ensure quality.

Background: Mass screening for cervical cancer has considerably reduced invasive cancer rates; however, Hispanic Americans have not fully benefited. This study examined the relationship of demographic, socioeconomic, and acculturation factors to diagnostic stage prior to preventive interventions in a large Hispanic community (San Diego, CA, 1988-1991)., Methods: Age-adjusted incidence rates (IR) were estimated for three subareas: Hispanic community targeted with interventions, comparison Hispanic community, and remainder of county. Incident cases of cervical cancer in the California Cancer Registry were used to calculate incidence rate ratios (IRR) of in situ to invasive stage cancer and estimate differences in early detection between Hispanics and white non-Hispanics. Multiple logistic regression was used to examine the relationship of cancer stage to census-linked income, education, poverty status, foreign birth, and language spoken., Results: The in situ cervical cancer IR is significantly lower for Hispanics than for white non-Hispanics in all three regions (P < 0.05). The overall IRR is 3.65 (95% CI 3.19, 4.18) for white non-Hispanics compared with 1.09 (95% CI 0.86, 1.38) for Hispanics. Hispanics in census tracts in the highest versus remaining quartiles for percentage of language-isolated households are at greater risk for invasive stage (OR = 2.10, 95% CI 1.27, 3. 40). White non-Hispanic women residing in census tracts in the highest versus lowest quartile of adults with less than 12 years education are at greater risk for invasive stage (OR = 2.10, 95% CI 1.31, 3.38)., Conclusions: Results show efforts aimed at cervical cancer early detection for Hispanic women are needed and well targeted. White non-Hispanic women in low-education communities are also at risk. Population-based methods in this study can focus efforts in communities needing preventive interventions., (Copyright 1998 American Health Foundation and Academic Press.)