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Background: Levels of plasma SARS-CoV-2 nucleocapsid (N) antigen may be an important biomarker in patients with COVID-19 and enhance our understanding of the pathogenesis of COVID-19. Objective: To evaluate whether levels of plasma antigen can predict short-term clinical outcomes and identify clinical and viral factors associated with plasma antigen levels in hospitalized patients with SARS-CoV-2. Design: Cross-sectional study of baseline plasma antigen level from 2540 participants enrolled in the TICO (Therapeutics for Inpatients With COVID-19) platform trial from August 2020 to November 2021, with additional data on day 5 outcome and time to discharge. Setting: 114 centers in 10 countries. Participants: Adults hospitalized for acute SARS-CoV-2 infection with 12 days or less of symptoms. Measurements: Baseline plasma viral N antigen level was measured at a central laboratory. Delta variant status was determined from baseline nasal swabs using reverse transcriptase polymerase chain reaction. Associations between baseline patient characteristics and viral factors and baseline plasma antigen levels were assessed using both unadjusted and multivariable modeling. Association between elevated baseline antigen level of 1000 ng/L or greater and outcomes, including worsening of ordinal pulmonary scale at day 5 and time to hospital discharge, were evaluated using logistic regression and Fine-Gray regression models, respectively. Results: Plasma antigen was below the level of quantification in 5% of participants at enrollment, and 1000 ng/L or greater in 57%. Baseline pulmonary severity of illness was strongly associated with plasma antigen level, with mean plasma antigen level 3.10-fold higher among those requiring noninvasive ventilation or high-flow nasal cannula compared with room air (95% CI, 2.22 to 4.34). Plasma antigen level was higher in those who lacked antispike antibodies (6.42 fold; CI, 5.37 to 7.66) and in those with the Delta variant (1.73 fold; CI, 1.41 to 2.13). Additional factors associated with higher baseline antigen level included male sex, shorter time since hospital admission, decreased days of remdesivir, and renal impairment. In contrast, race, ethnicity, body mass index, and immunocompromising conditions were not associated with plasma antigen levels. Plasma antigen level of 1000 ng/L or greater was associated with a markedly higher odds of worsened pulmonary status at day 5 (odds ratio, 5.06 [CI, 3.41 to 7.50]) and longer time to hospital discharge (median, 7 vs. 4 days; subhazard ratio, 0.51 [CI, 0.45 to 0.57]), with subhazard ratios similar across all levels of baseline pulmonary severity. Limitations: Plasma samples were drawn at enrollment, not hospital presentation. No point-of-care test to measure plasma antigen is currently available. Conclusion: Elevated plasma antigen is highly associated with both severity of pulmonary illness and clinically important patient outcomes. Multiple clinical and viral factors are associated with plasma antigen level at presentation. These data support a potential role of ongoing viral replication in the pathogenesis of SARS-CoV-2 in hospitalized patients.

ImportanceThe underlying biological risk factors for severe outcome due to SAR-CoV-2 infection are not well defined.ObjectiveTo determine the association between glucose-6-phosphate dehydrogenase (G6PD) deficiency and severity of COVID-19.Design, Setting, and ParticipantsThis retrospective cohort study included analysis of 24 700 veterans with G6PD enzyme testing prior to January 1, 2020, obtained through the US Veterans Health Administration national databases. These veterans were cross-referenced with the Veterans Administration COVID-19 Shared Data Resource for SARS-CoV-2 testing from February 15, 2020, to January 1, 2021. The final study population consisted of 4811 veterans who tested positive for SARS-CoV-2. Statistical analysis was performed from June to December 2021.ExposuresG6PD deficiency.Main Outcomes and MeasuresCOVID-19 severe illness, as defined by the Centers for Disease Control and Prevention: hospitalization, need for mechanical ventilation and/or intensive care unit admission, or in-hospital mortality after a positive SARS-CoV-2 test.ResultsAmong 4811 veterans in the Veterans Health Administration who had historical G6PD enzyme activity test results and SARS-CoV-2 positivity included in this study, 3868 (80.4%) were male, 1553 (32.3%) were Black, and 1855 (39%) were White; 1228 (25.5%) were 65 years or older and 3583 (74.5%) were younger than 65 years. There were no significant differences in age, body mass index, or Charlson Comorbidity Index were present between the veterans with G6PD deficiency and without G6PD deficiency. Among these veterans with SARS-CoV-2 infection, G6PD deficiency was more prevalent in Black male veterans (309 of 454 [68.1%]) compared with other racial and ethnic groups. Black male veterans less than 65 years of age with G6PD deficiency had approximately 1.5-fold increased likelihood of developing severe outcomes from SARS-CoV-2 infection compared with Black male veterans without G6PD deficiency (OR, 1.47; 95% CI, 1.03-2.09). In the small subset of White male veterans with G6PD deficiency, we observed an approximately 3.6-fold increased likelihood of developing severe outcomes from SARS-CoV-2 infection compared with White male veterans aged 65 years or older without G6PD deficiency (OR, 3.58; 95% CI, 1.64-7.80). This difference between veterans with and without G6PD deficiency was not observed in younger White male veterans or older Black male veterans, nor in smaller subsets of other male veterans or in female veterans of any age.Conclusions and RelevanceIn this cohort study of COVID-19–positive veterans, Black male veterans less than 65 years of age and White male veterans 65 years of age or older with G6PD deficiency had an increased likelihood of developing severe COVID-19 compared with veterans without G6PD deficiency. These data indicate a need to consider the potential for G6PD deficiency prior to treatment of patients with SARS-CoV-2 infection as part of clinical strategies to mitigate severe outcomes.

Idiopathic pulmonary fibrosis (IPF) is a fatal lung disease where the additional presence of pulmonary hypertension (PH) reduces survival. In particular, the presence of coexistent pulmonary vascular disease in patients with advanced lung parenchymal disease results in worse outcomes than either diagnosis alone. This is true with respect to the natural histories of these diseases, outcomes with medical therapies, and even outcomes following lung transplantation. Consequently, there is a striking need for improved treatments for PH in the setting of IPF. In this review, we summarize existing therapies from the perspective of molecular mechanisms underlying lung fibrosis and vasoconstriction/vascular remodelling and discuss potential future targets for pharmacotherapy. LINKED ARTICLES: This article is part of a themed issue on Risk factors, comorbidities, and comedications in cardioprotection. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v178.1/issuetoc.

BackgroundCoronavirus disease 2019 (Covid-19) pneumonia is often associated with hyperinflammation. Safety and efficacy of the anti–interleukin-6 receptor antibody tocilizumab was evaluated in patients hospitalized with Covid-19 pneumonia.MethodsNonventilated patients hospitalized with Covid-19 pneumonia were randomized (2:1) to tocilizumab (8 mg/kg intravenous) or placebo plus standard care. Sites enrolling high-risk and minority populations were emphasized. The primary endpoint was cumulative proportion of patients requiring mechanical ventilation or who had died by Day 28.ResultsOf 389 randomized patients, 249 patients received tocilizumab and 128 received placebo in the modified intent-to-treat population (Hispanic/Latino, 56.0%; Black/African American, 14.9%; American Indian/Alaska Native, 12.7%; White, 12.7%; other/unknown, 3.7%). The cumulative proportion (95% confidence interval [CI]) of patients requiring mechanical ventilation or who had died by Day 28 was 12.0% (8.52% to 16.86%) and 19.3 % (13.34% to 27.36%) for the tocilizumab and placebo arms, respectively (log-rank P=0.0360; hazard ratio, 0.56 [95% CI, 0.33 to 0.97]). Median time to clinical failure up to Day 28 favored tocilizumab over placebo (hazard ratio 0.55 [95% CI, 0.33 to 0.93]). All-cause mortality by Day 28 was 10.4% with tocilizumab and 8.6% with placebo (weighted difference, 2.0% [95% CI, – 5.2% to 7.8%). In the safety population, serious adverse events occurred in 15.2% of tocilizumab patients (38/250 patients) and 19.7% of placebo patients (25/127).ConclusionsThis trial demonstrated the efficacy and safety of tocilizumab over placebo in reducing the likelihood of progression to requiring mechanical ventilation or death in nonventilated patients hospitalized with Covid-19 pneumonia.Trial registrationClinicalTrials.govNCT04372186

The 1918 influenza killed approximately 50 million people in a few short years, and now, the world is facing another pandemic. In December 2019, a novel coronavirus named severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused an international outbreak of a respiratory illness termed coronavirus disease 2019 (COVID-19) and rapidly spread to cause the worst pandemic since 1918. Recent clinical reports highlight an atypical presentation of acute respiratory distress syndrome (ARDS) in COVID-19 patients characterized by severe hypoxemia, an imbalance of the renin–angiotensin system, an increase in thrombogenic processes, and a cytokine release storm. These processes not only exacerbate lung injury but can also promote pulmonary vascular remodeling and vasoconstriction, which are hallmarks of pulmonary hypertension (PH). PH is a complication of ARDS that has received little attention; thus, we hypothesize that PH in COVID-19-induced ARDS represents an important target for disease amelioration. The mechanisms that can promote PH following SARS-CoV-2 infection are described. In this review article, we outline emerging mechanisms of pulmonary vascular dysfunction and outline potential treatment options that have been clinically tested.

Congenital diaphragmatic hernia (CDH) leads to pathophysiologic pulmonary vasoreactivity. Previous studies show that mesenchymal stromal cell-derived extracellular vesicles (MSCEv) inhibit lung inflammation and vascular remodeling. We characterize MSCEv and human pulmonary artery endothelial cell (HPAEC) interaction, as well as the pulmonary artery (PA) response to MSCEv treatment. HPAECs were cultured with and without exposure to nitrofen (2,4-dichloro-phenyl-p-nitrophenylether) and treated with MSCEv. HPAEC viability, architecture, production of reactive oxygen species (ROS), endothelial dysfunction-associated protein levels (PPARγ, LOX-1, LOX-2, nuclear factor-κB [NF-κB], endothelial NO synthase [eNOS], ET-1 [endothelin 1]), and the nature of MSCEv-cellular interaction were assessed. Newborn rodents with and without CDH (nitrofen model and Sprague-Dawley) were treated with intravascular MSCEv or vehicle control, and their PAs were isolated. Contractility was assessed by wire myography. The contractile (KCL and ET-1) and relaxation (fasudil) responses were evaluated. HPAEC viability correlated inversely with nitrofen dose, while architectural compromise was directly proportional. There was a 2.1 × increase in ROS levels in nitrofen HPAECs (

We have previously shown Twik‐2−/− mice develop pulmonary hypertension and vascular remodeling. We hypothesized that distal pulmonary arteries (D‐PAs) of the Twik‐2−/− mice are hypercontractile under physiological venous conditions due to altered electrophysiologic properties between the conduit and resistance vessels in the pulmonary vascular bed. We measured resting membrane potential and intracellular calcium through Fura‐2 in freshly digested pulmonary artery smooth muscles (PASMCs) from both the right main (RM‐PA) and D‐PA (distal) regions of pulmonary artery from WT and Twik‐2−/− mice. Whole segments of RM‐PAs and D‐PAs from 20 to 24‐week‐old wildtype (WT) and Twik‐2−/− mice were also pressurized between two glass micropipettes and bathed in buffer with either arterial or venous conditions. Abluminally‐applied phenylephrine (PE) and U46619 were added to the buffer at log increments and vessel diameter was measured. All values were expressed as averages with ±SEM. Vasoconstrictor responses did not differ between WT and Twik‐2−/− RM‐PAs under arterial conditions. Under venous conditions, Twik‐2−/− RM‐PAs showed an increased sensitivity to PE with a lower EC50 (P = 0.02). Under venous conditions, Twik‐2−/− D‐PAs showed an increase maximal vasoconstrictor response to both phenylephrine and U46619 compared to the WT mice (P

Group III pulmonary hypertension (PH) is a highly prevalent and deadly lung disorder with limited treatment options other than transplantation. Group III PH affects patients with ongoing chronic lung injury, such as idiopathic pulmonary fibrosis (IPF). Between 30 and 40% of patients with IPF are diagnosed with PH. The diagnosis of PH has devastating consequences to these patients, leading to increased morbidity and mortality, yet the molecular mechanisms involved in the development of PH in patients with chronic lung disease remain elusive. Our hypothesis was that the hypoxic-adenosinergic system is enhanced in patients with group III PH compared with patients with IPF with no PH. Explanted lung tissue was analyzed for markers of the hypoxic-adenosine axis, including expression levels of hypoxia-inducible factor (HIF)-1A, adenosine A2B receptor, CD73, and equilibrative nucleotide transporter-1. In addition, we assessed whether altered mitochondrial metabolism was present in these samples. Increased expression of HIF-1A was observed in tissues from patients with group III PH. These changes were consistent with increased evidence of adenosine accumulation in group III PH. A novel observation of our study was of evidence suggesting altered mitochondrial metabolism in lung tissue from group III PH leading to increased succinate levels that are able to further stabilize HIF-1A. Our data demonstrate that the hypoxic-adenosine axis is up-regulated in group III PH and that subsequent succinate accumulation may play a part in the development of group III PH.

The present methodology teaches the investigator how to measure and use the LAV as a surrogate of chronic elevations in Left Ventricular diastolic pressure through echocardiography, as well as to obtain measurements of the Aorta and PA diameter in mice. Mice older than 10 d of age can be analyzed using the present technique. The technique is composed of 3 main steps: set-up, image acquisition, and image analysis. The set-up step consists of getting the mouse anesthetized with 1% isoflurane, shaving it, and taping it in a supine position to a heated EKG board where the image acquisition will take place. The image acquisition step consists of learning to identify the cardiac structures and obtaining all the required images with its correspondent probe and axis in order to be able to calculate volumes and diameters. The image analysis step consists of measuring the previously acquired images with the aid of computer software. Advantages of the proposed technique include a fast (15 min) procedure that would allow the researcher to evaluate interventions in a non-invasive, non-terminal approach and therefore follow the same mouse over time; each mouse can be used as its own control. This fact plus having the same operator perform all the acquisition and analysis for the entire experiment minimizes the limitation of operator-dependency. The present methodology is useful for mouse researchers in cardiovascular and pulmonary medicine.

Patients with chronic obstructive pulmonary disease and pulmonary hypertension (PH-COPD) have an increased risk of hospitalizations and death compared to COPD alone. Identifying PH in COPD is challenging because performing right heart catheterization, the gold standard for PH diagnosis, is invasive and not routinely performed. Clinical characterization of COPD patients at risk who are progressing toward PH will aid therapeutic development at earlier stages of progressively fatal PH-COPD. We studied the records of 5,45,086 patients in a large Veterans Affairs healthcare network (2000-2012) with a primary discharge diagnosis of COPD based on encounters' ICD-9 codes and further stratified into those who received an additional ICD-9 code for a PH diagnosis. Patients with PH-COPD were assigned to one of the four subgroups: those with (a) no history of exacerbation or hospital admissions, (b) history of exacerbations but no hospital admissions, (c) hospital admissions unrelated to COPD and (d) history of COPD exacerbation-related hospital admissions. We also examined the COPD and COPD-PH cohorts for associated comorbidities such as cardiac disease and the presence of obstructive sleep apnea (OSA). A regression analysis revealed that patients with COPD exacerbation-related hospital admissions had 7 × higher risk of having a concomitant clinical diagnosis of PH compared to non-hospitalized patients. COPD-PH patients had higher rates of cardiac comorbidities (89% vs. 66%) and OSA (34% vs. 16%) compared to COPD alone. We conclude that COPD patients hospitalized for COPD exacerbations are at a higher risk for developing PH, and hospitalized COPD patients with cardiac comorbidities and/or OSA should be screened as at-risk population for developing PH.

Cross-sectional studies of T-cell responses to self-antigens correlate with baseline emphysema severity.We investigated whether clinical and/or immunological factors could predict disease progression, such as emphysema, FEV1, and 6-minute-walk distance (6MWD), in former and active smokers in a 5-year prospective study.We recruited 224 ever smokers over 40 years of age and with greater than a 15 pack-year smoking history.Repeated spirometry, 6MWD, and peripheral blood T-cell cytokine responses to lung elastin fragments were measured. Baseline and repeat chest computed tomography (CT) scans (34 to 65 mo apart) were used to quantify emphysema progression. Of the 141 ever-smokers with baseline and repeat CT scans, the mean (SD) annual rate of change in percent emphysema was +0.46 (0.92), ranging from -1.8 to +4.1. In multivariable analyses, the rate of emphysema progression was greater in subjects who had lower body mass index (BMI) (+0.15 per 5-unit decrease in BMI; 95% confidence interval, +0.03 to +0.29). In active smokers, increased IFN-γ and IL-6 T-cell responses had a positive association with the annual rate of emphysema progression. Male sex and IL-6 T-cell responses to elastin fragments were significantly associated with annual 6MWD decline, whereas IL-13 was associated with an increase in annual 6MWD.The rate of emphysema progression quantified by CT scans among ever-smokers was highly variable; clinical factors and biomarkers explained only some of the variability. Aggressive clinical care that targets active smokers with autoreactive T cells and low BMI may temporize progression of emphysema.

TWIK-2 ( KCNK6 ) is a member of the 2-pore domain (K 2P ) family of potassium channels, which are highly expressed in the vascular system. We tested the hypothesis that TWIK-2 deficiency leads to pulmonary hypertension. TWIK-2 knockout mice and their wildtype littermates at 8 weeks of age had similar mean right ventricular systolic pressures (24±3 and 21±3 mm Hg, respectively.) Significantly, by 20 weeks of age, the mean right ventricular systolic pressures in TWIK-2 knockout mice increased to 35±3 mm Hg ( P ≤0.036), whereas mean right ventricular systolic pressures in wildtype littermates remained at 22±3 mm Hg. Elevated mean right ventricular systolic pressures in the TWIK-2 knockout mice was accompanied by pulmonary vascular remodeling as determined by a 25% increase in the cross-sectional area of the vessels occupied by the vessel wall. Additionally, secondary branches of the pulmonary artery from 20-week-old TWIK-2 knockout mice showed an enhanced contractile response to U46619 (10 –6 moles/L), a thromboxane A2 mimetic, which was completely abolished with the Rho-kinase inhibitor, Y27632 (10 –6 and 10 –5 moles/L). Treatment of TWIK-2 knockout mice with the Rho-kinase inhibitor, fasudil, in the drinking water for 12 weeks, abolished the development of pulmonary hypertension and attenuated the vessel remodeling. We concluded that mice deficient in the TWIK-2 channel develop pulmonary hypertension between 8 and 20 weeks of age through a mechanism involving Rho-kinase. Our results suggest that downregulation of TWIK-2 in the pulmonary vasculature may be an underlying mechanism in the development of pulmonary hypertension.

Disorders associated with airway inflammation arise through the activation of diverse immunological mechanisms: in most instances, these are initiated through exposure to distinct environmental agents. These conditions involve both the upper and lower airways and include some of the most common of all human illnesses, such as asthma, allergic rhinitis, chronic rhinosinusitis, and emphysema. A common feature of all inflammatory airway disorders is airway obstruction, and therapies typically aim to relieve airway obstruction and suppress inflammation. The allergic airway diseases may be linked to infections caused by viruses and fungi, suggesting that antimicrobial therapy may be an important treatment option. Future treatments for all inflammatory airway diseases are likely to focus on blocking key immune developmental pathways involving T-helper 1 (Th1), Th2, and Th17 cells.

Src kinases are key regulators of cellular proliferation, survival, motility, and invasiveness. They play important roles in the regulation of inflammation and cancer. Overexpression or hyperactivity of c-Src has been implicated in the development of various types of cancer, including lung cancer. Src inhibition is currently being investigated as a potential therapy for non-small cell lung cancer in Phase I and II clinical trials. The mechanisms of Src implication in cancer and inflammation are linked to the ability of activated Src to phosphorylate multiple downstream targets that mediate its cellular effector functions. In this study, we reveal that inducible nitric-oxide synthase (iNOS), an enzyme also implicated in cancer and inflammation, is a downstream mediator of activated Src. We elucidate the molecular mechanisms of the association between Src and iNOS in models of inflammation induced by lipopolysaccharide and/or cytokines and in cancer cells and tissues. We identify human iNOS residue Tyr(1055) as a target for Src-mediated phosphorylation. These results are shown in normal cells and cancer cells as well as in vivo in mice. Importantly, such posttranslational modification serves to stabilize iNOS half-life. The data also demonstrate interactions and co-localization of iNOS and activated Src under inflammatory conditions and in cancer cells. This study demonstrates that phosphorylation of iNOS by Src plays an important role in the regulation of iNOS and nitric oxide production and hence could account for some Src-related roles in inflammation and cancer.

Recent evidence suggests that aggresome formation is a physiologic stress response not limited to misfolded proteins. That stress response, termed "physiologic aggresome," is exemplified by aggresome formation of inducible nitric oxide synthase (iNOS), an important host defense protein. CHIP (carboxy terminus of Hsp70-interacting protein) is a highly conserved protein that has been shown to mediate substrate ubiquitination and degradation by the proteasome. In this study, we show that CHIP has a previously unexpected critical role in the aggresome pathway. CHIP interacts with iNOS and promotes its ubiquitination and degradation by the proteasome as well as its sequestration to the aggresome. CHIP-mediated iNOS targeting to the proteasome sequentially precedes CHIP-mediated iNOS sequestration to the aggresome. CHIP is required for iNOS preaggresome structures to form a mature aggresome. Furthermore, CHIP is required for targeting the mutant form of cystic fibrosis transconductance regulator (CFTRDeltaF508) to the aggresome. Importantly, the ubiquitin ligase function of CHIP is required in targeting preaggresomal structures to the aggresome by promoting an iNOS interaction with histone deacetylase 6, which serves as an adaptor between ubiquitinated proteins and the dynein motor. This study reveals a critical role for CHIP in the aggresome pathway.