Lymphopenia in the Adult Population With Fontan Physiology: A Potential New Marker for Disease Assessment.

Background: Patients with complex congenital heart disease and Fontan palliation frequently develop extracardiac disease, including hematologic abnormalities, such as lymphopenia. However, the clinical implications of this finding are poorly understood and are therefore the topic of this investigation. Methods: Patients with Fontan physiology in our centre (1999-2018) were evaluated for the presence and impact of lymphopenia. The cohort was divided into a group with lymphopenia (L) (2 consecutive absolute lymphocyte counts ≤ 1∗103 K/ µL) and a group who had never had lymphopenia (NL). Clinical characteristics and hospital admissions (762 patient-years) were evaluated. Results: In 62 adult patients with Fontan physiology (aged 34 ± 9 years; 32 women [52%]), the patients who developed lymphopenia earliest did so 8 years after Fontan completion, with up to 60% of patients developing lymphopenia by 30 years. Lymphopenia was found to be associated with portal hypertension (varices, ascites, splenomegaly, and thrombocytopenia [VAST] score)-NL: 0 (0-2) vs L: 2 (0-4), P < 0.0001). A total of 76 heart failure and 81 arrhythmia-associated admissions occurred per 1000 patient-years. At 40 years post-Fontan, the probability of a heart failure admission was higher in the L group (L: 51 [86%] vs NL: 8 [14%], P < 0.01). Conclusions: Adult patients with Fontan physiology and lymphopenia demonstrated portal hypertension and lymphatic dysfunction more commonly, perhaps suggesting that this may be a marker of Fontan congestion and early Fontan failure. Further investigation into the relationship between lymphopenia, clinical outcomes, and Fontan function is needed.

Contexte: Chez les patients atteints d'une cardiopathie congénitale complexe ayant subi une intervention de Fontan, il est fréquent de voir apparaître des maladies extracardiaques, dont des anomalies hématologiques, comme la lymphopénie. Cependant, les implications cliniques de cette observation sont mal comprises et font donc l'objet de cette étude. Méthodologie: La présence et l'impact d'une lymphopénie ont été évalués chez des patients présentant une physiologie de Fontan dans notre centre (1999-2018). La cohorte a été divisée en un groupe composé de sujets atteints de lymphopénie (L) (2 mesures consécutives du nombre absolu de lymphocytes ≤ 1 x 103 K/µL) et un groupe de sujets n'ayant jamais présenté de lymphopénie (NL). Les caractéristiques initiales et les hospitalisations (762 années-patients) ont été évaluées. Résultats: Chez 62 adultes présentant une physiologie de Fontan (âgés de 34 ± 9 ans; 32 femmes [52 %]), la lymphopénie est apparue au plus tôt 8 ans après l'intervention de Fontan, avant 30 ans chez jusqu'à 60 % des patients. La lymphopénie a été associée à l'hypertension portale (score varices, ascite, splénomégalie et thrombocytopénie [VAST]) ­ NL : 0 (0-2) vs L : 2 (0-4), p < 0,0001. Au total, il y a eu 76 hospitalisations pour insuffisance cardiaque et 81 pour arythmie pour 1000 années-patients. Quarante ans après l'intervention de Fontan, la probabilité d'une hospitalisation pour insuffisance cardiaque était plus élevée dans le groupe L que dans le groupe NL (L : 51 [86 %] vs NL : 8 [14 %], p < 0,01). Conclusions: L'hypertension portale et la dysfonction lymphatique étaient plus fréquentes chez les adultes présentant une physiologie de Fontan et une lymphopénie, ce qui laisse peut-être entendre que ce pourrait être un marqueur d'une congestion et d'une défaillance précoce du système Fontan. D'autres recherches sur le lien entre la lymphopénie, les issues cliniques et la fonction du système Fontan sont nécessaires.

REDD1 Deletion Suppresses NF-κB Signaling in Cardiomyocytes and Prevents Deficits in Cardiac Function in Diabetic Mice.

Activation of the transcription factor NF-κB in cardiomyocytes has been implicated in the development of cardiac function deficits caused by diabetes. NF-κB controls the expression of an array of pro-inflammatory cytokines and chemokines. We recently discovered that the stress response protein regulated in development and DNA damage response 1 (REDD1) was required for increased pro-inflammatory cytokine expression in the hearts of diabetic mice. The studies herein were designed to extend the prior report by investigating the role of REDD1 in NF-κB signaling in cardiomyocytes. REDD1 genetic deletion suppressed NF-κB signaling and nuclear localization of the transcription factor in human AC16 cardiomyocyte cultures exposed to TNFα or hyperglycemic conditions. A similar suppressive effect on NF-κB activation and pro-inflammatory cytokine expression was also seen in cardiomyocytes by knocking down the expression of GSK3ß. NF-κB activity was restored in REDD1-deficient cardiomyocytes exposed to hyperglycemic conditions by expression of a constitutively active GSK3ß variant. In the hearts of diabetic mice, REDD1 was required for reduced inhibitory phosphorylation of GSK3ß at S9 and upregulation of IL-1ß and CCL2. Diabetic REDD1+/+ mice developed systolic functional deficits evidenced by reduced ejection fraction. By contrast, REDD1-/- mice did not exhibit a diabetes-induced deficit in ejection fraction and left ventricular chamber dilatation was reduced in diabetic REDD1-/- mice, as compared to diabetic REDD1+/+ mice. Overall, the results support a role for REDD1 in promoting GSK3ß-dependent NF-κB signaling in cardiomyocytes and in the development of cardiac function deficits in diabetic mice.

Sudden death in adults with repaired coarctation of the aorta: A case for sex-based risk factors.

Background: Sudden cardiac death (SCD) is an important risk for adults with repaired coarctation of the aorta (rCoA). We aimed determine if there are clinical risk factors for SCD in adults with rCoA. Methods and results: SCD events and clinical data from all adults with rCoA at a tertiary care center (2007-2017) were evaluated. In 167 adults with rCoA (39 ± 11 years old, 75 (45%) female) SCD occurred in 8 (5%) (vs. age-matched adults 0.9%). Those with SCD demonstrated significant QTc prolongation (QTc: 479 ± 16 vs. 434 ± 30 msec, p < 0.001). Overall, adults with rCoA and a prolonged sex-normative QTc interval had a 12-fold increased risk of SCD (x2 (1) = 12.3, p < 0.001), with men sustaining SCD at younger ages (42 ± 13 years vs. women 60 ± 10 years, p < 0.05). Multiple logistic regression modeling demonstrated that prolonged QTc selectively advanced risk for SCD in men only (x2 QTc prolongation 8.46, p < 0.005 and x2 age 0.29, p = 0.587), whereas in women, age was associated with SCD risk (x2 QTc prolongation 2.84, p = 0.092 and x2 age 7.81, p = 0.005). Non-sustained ventricular tachycardia, ventricular dysfunction, and myocardial fibrosis did not significantly impact SCD risk. Conclusions: There is an unanticipated high burden of SCD in adults with rCoA, occurring in men at younger age than women, suspicious for primary electrophysiologic dysfunction. Future investigation of sex-specific SCD risk in rCoA is important to better understand this disease and its late phenotype.

Study of heart function in PRE-Eclampsia during and after PreGnancy (SHePREG): The pilot cohort.

BACKGROUND: Pre-eclampsia with severe features (severe PreE) is associated with heart dysfunction, yet the impact beyond pregnancy, including its association with cardiomyopathic genetic polymorphisms, remains poorly understood. OBJECTIVE: We aimed to characterize the temporal impact of severe PreE on heart function through the 4th trimester in women with and without deleterious cardiomyopathic genetic variants. METHODS: Pregnant women were enrolled to undergo transthoracic echocardiography (TTE) in late pregnancy and 3 months postpartum. In women with severe PreE a targeted approach to identify pathogenic cardiomyopathic genetic polymorphisms was undertaken, and heart function was compared in carriers and noncarriers. RESULTS: Pregnant women (32 ± 4 years old, severe PreE = 14, control = 8) were enrolled between 2019 - 2021. Women with severe PreE displayed attenuated myocardial relaxation (mitral e' = 11.0 ± 2.2 vs 13.2 ± 2.3 cm/sec, P < .05) in late pregnancy, and on in-silico analysis, deleterious cardiomyopathic variants were found in 58%. At 103 ± 33 days postpartum, control women showed stability in myocardial relaxation (Mitral e' Entry: 13.2 ± 2.3 vs Postpartum: 13.9 ± 1.7cm/sec, P = .464), and genetic negative severe PreE women (G-) demonstrated recovery of diastolic function to control level (Mitral e' Entry: 11.0 ± 3.0 vs Postpartum 13.7 ± 2.8cm/sec, P < .001), unlike their genetic positive (G+) counterparts (Mitral e' Entry: 10.5 ± 1.7 vs Postpartum 10.8 ± 2.4cm/sec, P = .853). CONCLUSIONS: Postpartum recovery of heart function after severe PreE is attenuated in women with deleterious cardiomyopathic genetic polymorphisms.

Anesthetic Care of the Pregnant Patient With Cardiovascular Disease: A Scientific Statement From the American Heart Association.

The pregnancy-related mortality rate in the United States is excessively high. The American Heart Association is dedicated to fighting heart disease and recognizes that cardiovascular disease, preexisting or acquired during pregnancy, is the leading cause of maternal mortality in the United States. Comprehensive scientific statements from cardiology and obstetrics experts guide the treatment of cardio-obstetric patients before, during, and after pregnancy. This scientific statement aims to highlight the role of specialized cardio-obstetric anesthesiology care, presenting a systematic approach to the care of these patients from the anesthesiology perspective. The anesthesiologist is a critical part of the pregnancy heart team as the perioperative physician who is trained to prevent or promptly recognize and treat patients with peripartum cardiovascular decompensation. Maternal morbidity is attenuated with expert anesthesiology peripartum care, which includes the management of neuraxial anesthesia, inotrope and vasopressor support, transthoracic echocardiography, optimization of delivery location, and consideration of advanced critical care and mechanical support when needed. Standardizing the anesthesiology approach to patients with high peripartum cardiovascular risk and ensuring that cardio-obstetrics patients have access to the appropriate care team, facilities, and advanced cardiovascular therapies will contribute to improving peripartum morbidity and mortality.

PERK/ATF4-dependent expression of the stress response protein REDD1 promotes proinflammatory cytokine expression in the heart of obese mice.

Endoplasmic reticulum (ER) stress and inflammation are hallmarks of myocardial impairment. Here, we investigated the role of the stress response protein regulated in development and DNA damage 1 (REDD1) as a molecular link between ER stress and inflammation in cardiomyocytes. In mice fed a high-fat high-sucrose (HFHS, 42% kcal fat, 34% sucrose by weight) diet for 12 wk, REDD1 expression in the heart was increased in coordination with markers of ER stress and inflammation. In human AC16 cardiomyocytes exposed to either hyperglycemic conditions or the saturated fatty acid palmitate, REDD1 expression was increased coincident with ER stress and upregulated expression of the proinflammatory cytokines IL-1ß, IL-6, and TNFα. In cardiomyocytes exposed to hyperglycemic/hyperlipidemic conditions, pharmacological inhibition of the ER kinase protein kinase RNA-like endoplasmic reticulum kinase (PERK) or knockdown of the transcription factor ATF4 prevented the increase in REDD1 expression. REDD1 deletion reduced proinflammatory cytokine expression in both cardiomyocytes exposed to hyperglycemic/hyperlipidemic conditions and in the hearts of obese mice. Overall, the findings support a model wherein HFHS diet contributes to the development of inflammation in cardiomyocytes by promoting REDD1 expression via activation of a PERK/ATF4 signaling axis.NEW & NOTEWORTHY Interplay between endoplasmic reticulum stress and inflammation contributes to cardiovascular disease progression. The studies here identify the stress response protein known as REDD1 as a missing molecular link that connects the development of endoplasmic reticulum stress with increased production of proinflammatory cytokines in the hearts of obese mice.

Heart Failure in Complex Congenital Heart Disease of the Adult.

PURPOSE OF REVIEW: Adult congenital heart disease (ACHD) patients have demonstrated improved survival, especially those with severely complex disease, mainly single-ventricle/Fontan physiology and those with a systemic right ventricle. We describe the heart failure phenotypes of complex CHD, reversible causes for heart failure, and considerations for advanced therapy. RECENT FINDINGS: While initially marketed for application to patients with acquired causes for heart failure, newer devices and technologies have started to be used in the ACHD population. After reversible causes for heart failure in CHD are addressed, it is reasonable to consider use of new device-based technologies and orthotopic heart transplant (OHT) for end-stage disease. New heart failure technology and organ transplant should carefully be considered and applied in complex ACHD, where there may be significant improvement in morbidity and mortality.

Physician Wellness in Academic Cardiovascular Medicine: A Scientific Statement From the American Heart Association.

Academic medicine as a practice model provides unique benefits to society. Clinical care remains an important part of the academic mission; however, equally important are the educational and research missions. More specifically, the sustainability of health care in the United States relies on an educated and expertly trained physician workforce directly provided by academic medicine models. Similarly, the research charge to deliver innovation and discovery to improve health care and to cure disease is key to academic missions. Therefore, to support and promote the growth and sustainability of academic medicine, attracting and engaging top talent from fellows in training and early career faculty is of vital importance. However, as the health care needs of the nation have risen, clinicians have experienced unprecedented demand, and individual wellness and burnout have been examined more closely. Here, we provide a close look at the unique drivers of burnout in academic cardiovascular medicine and propose system-level and personal interventions to support individual wellness in this model.

Operational and Ethical Considerations for a National Adult Congenital Heart Disease Database.

As more adults survive with congenital heart disease, the need to better understand the long-term complications, and comorbid disease will become increasingly important. Improved care and survival into the early and late adult years for all patients equitably requires accurate, timely, and comprehensive data to support research and quality-based initiatives. National data collection in adult congenital heart disease will require a sound foundation emphasizing core ethical principles that acknowledge patient and clinician perspectives and promote national collaboration. In this document we examine these foundational principles and offer suggestions for developing an ethically responsible and inclusive framework for national ACHD data collection.

Imaging-Based Risk Stratification for Recurrence Risk in Women with a History of Peripartum Cardiomyopathy.

OBJECTIVE: Peripartum cardiomyopathy (PPCM) affects 1:1,000 U.S. pregnancies, and while many recover from the disease, the risk of recurrence in subsequent pregnancy (SSP) is high. This study aims to evaluate the utility of left ventricular ejection fraction (LVEF) and global longitudinal strain (GLS) to predict the risk of recurrence of PPCM in SSP. STUDY DESIGN: We retrospectively evaluated outcomes in women with a history of PPCM and SSP at a large-volume cardioobstetrics program (2008-2019). RESULTS: There were 18 women who had incident PPCM and pursued SSP. Of 24 pregnancies in these women, 8 (33%) were complicated by the development of recurrent PPCM. LVEF ≥ 52% or GLS ≤ -16 was associated with a low risk of recurrent PPCM. CONCLUSION: Approximately one-third of women with PPCM developed recurrent PPCM in SSP. LVEF and GLS on prepregnancy echocardiography may predict the risk of recurrence. Additional studies evaluating risk for recurrence are required to better understand which women are the safest to consider SSP. KEY POINTS: · Peripartum cardiomyopathy affects 1:1000 US pregnancies.. · Approximately one third of women with a history of peripartum cardiomyopathy developed recurrent disease in a subsequent pregnancy.. · A left ventricular ejection fraction ≥52% or global longitudinal strain ≤-16 on echocardiogram is associated with a low risk of recurrence..

Maternal and fetal outcomes in pregnant women with pulmonary hypertension: The impact of left heart disease.

Background: Pulmonary hypertension (PH) due to left heart disease (World Health Organization (WHO) Group 2 PH) is the largest PH subgroup, however most reports of PH in pregnancy focus on patients with pulmonary arterial hypertension (WHO Group 1 PH). We evaluated pregnancy outcomes across WHO PH subgroups. Methods: We performed a retrospective single center cohort study of maternal and fetal outcomes in pregnant women with PH (2004-2018). Results: We analyzed outcomes of 70 pregnancies in 70 women with PH (30 ± 6 years-old), classified as WHO Group 1 PH (12 (17%)), Group 2 PH (45 (64%)), Group 3 PH (4 (6%)) and Group 5 PH (9 (13%)). Although no peripartum death occurred, 3 (4.3%) women with WHO Group 2 PH had late mortality (7 ± 4 months post- partum). Additionally, 33 major adverse cardiac events occurred in 26 (37%) women, preterm birth occurred in 32 (49%), and post-partum hemorrhage in 10 (14%), such that only 24 (37%) women completed a viable pregnancy free of an adverse cardiac, obstetric or fetal/neonatal event. Major adverse cardiac events were predominantly due to heart failure (24 (73%)), occurring only in WHO Groups 1 and 2 PH (3 (25%) women vs. 17 (38%), p = 0.07), and significantly associated with pre-eclampsia, left ventricular ejection fraction ≤45%, maternal diabetes, and systemic hypertension. Conclusions: WHO Group 2 PH carries similar risk for maternal cardiovascular events when compared to women with WHO Group 1 PH. Further studies evaluating maternal risk in this cohort are needed.

New mechanistic insights to PLOD1-mediated human vascular disease.

Heritable thoracic aortic disease and familial thoracic aortic aneurysm/dissection are important causes of human morbidity/mortality, most without identifiable genetic cause. In a family with familial thoracic aortic aneurysm/dissection, we identified a missense p. (Ser178Arg) variant in PLOD1 segregating with disease, and evaluated PLOD1 enzymatic activity, collagen characteristics and in human aortic vascular smooth muscle cells, studied the effect on function. Comparison with homologous PLOD3 enzyme indicated that the pathogenic variant may affect the N-terminal glycosyltransferase domain, suggesting unprecedented PLOD1 activity. In vitro assays demonstrated that wild-type PLOD1 is capable of processing UDP-glycan donor substrates, and that the variant affects the folding stability of the glycosyltransferase domain and associated enzymatic functions. The PLOD1 substrate lysine was elevated in the proband, however the enzymatic product hydroxylysine and total collagen content was not different, albeit despite collagen fibril narrowing and preservation of collagen turnover. In VSMCs overexpressing wild-type PLOD1, there was upregulation in procollagen gene expression (secretory function) which was attenuated in the variant, consistent with loss-of-function. In comparison, si-PLOD1 cells demonstrated hypercontractility and upregulation of contractile markers, providing evidence for phenotypic switching. Together, the findings suggest that the PLOD1 product is preserved, however newly identified glucosyltransferase activity of PLOD1 appears to be affected by folding stability of the variant, and is associated with compensatory vascular smooth muscle cells phenotypic switching to support collagen production, albeit with less robust fibril girth. Future studies should focus on the impact of PLOD1 folding/variant stability on the tertiary structure of collagen and ECM interactions.

Heart failure in pregnancy: what is the long-term impact of pregnancy on cardiac function? A tertiary care centre experience and systematic review.

BACKGROUND: Women with cardiomyopathy (CM) are often advised against pregnancy due to risk for major adverse cardiovascular events (MACE). However, the impact of CM subtype on maternal MACE is not understood, and so we sought to evaluate the influence of CM phenotype on maternal outcomes, as well as the effect on immediate and late left ventricular function. METHODS: We evaluated all pregnant women in our high-risk maternal cardiovascular programme (2009-2019). Composite maternal MACE included: death, inotrope use, left ventricular assist device, orthotopic heart transplant and/or escalation in transplant listing status, acute decompensated heart failure and sustained ventricular arrhythmia. RESULTS: Among 875 women followed, 32 had CM (29±7 years old, left ventricular ejection fraction (LVEF) 41%±12%): 3 ischaemic CM (ICM), 10 peripartum CM (PPCM) and 19 non-ICM (NICM). MACE events occurred in 6 (18%) women (PPCM: 2 (33%), NICM: 4 (67%)). There was no difference in LVEF at baseline, however, women with MACE had significantly lower LVEF both early (LVEF: 27±5% vs . 41±2%, p<0.05) and late post partum (LVEF: 28±5% vs . 44±2%, p<0.01). CONCLUSIONS: In this contemporary cohort of women with CM, maternal MACE rates were lower than previously reported, and were less common in PPCM as compared with ICM and NICM. Heart function in women with MACE was negatively impacted immediately after delivery and in late postpartum follow-up, suggesting that pregnancy itself likely has influence on future left ventricular function in women with underlying CM.

Inherited Variants in SCARB1 Cause Severe Early-Onset Coronary Artery Disease.

[Figure: see text].

Giant ankyrin-G regulates cardiac function.

Cardiovascular disease (CVD) remains the most common cause of adult morbidity and mortality in developed nations. As a result, predisposition for CVD is increasingly important to understand. Ankyrins are intracellular proteins required for the maintenance of membrane domains. Canonical ankyrin-G (AnkG) has been shown to be vital for normal cardiac function, specifically cardiac excitability, via targeting and regulation of the cardiac voltage-gated sodium channel. Noncanonical (giant) AnkG isoforms play a key role in neuronal membrane biogenesis and excitability, with evidence for human neurologic disease when aberrant. However, the role of giant AnkG in cardiovascular tissue has yet to be explored. Here, we identify giant AnkG in the myocardium and identify that it is enriched in 1-week-old mice. Using a new mouse model lacking giant AnkG expression in myocytes, we identify that young mice displayed a dilated cardiomyopathy phenotype with aberrant electrical conduction and enhanced arrhythmogenicity. Structural and electrical dysfunction occurred at 1 week of age, when giant AnkG was highly expressed and did not appreciably change in adulthood until advanced age. At a cellular level, loss of giant AnkG results in delayed and early afterdepolarizations. However, surprisingly, giant AnkG cKO myocytes display normal INa, but abnormal myocyte contractility, suggesting unique roles of the large isoform in the heart. Finally, transcript analysis provided evidence for unique pathways that may contribute to the structural and electrical findings shown in giant AnkG cKO animals. In summary, we identify a critical role for giant AnkG that adds to the diversity of ankyrin function in the heart.

Cardiovascular outcomes of pregnancy in Turner syndrome.

OBJECTIVES: Women with Turner syndrome (TS) are frequently counselled against pregnancy due to lack of data and unclear aortic dissection risk. However, with advances in fertility therapy, more women with TS are contemplating pregnancy. This study compared rates of adverse cardiovascular (CV) outcomes among: (1) pregnant and non-pregnant women with TS and (2) pregnant women with TS with/without structural heart disease. METHODS: Retrospective analysis of pregnant and age-matched non-pregnant controls with TS (2005-2017) across 10 CV centres was done. Data were collected at initial evaluation in pregnancy and outcomes were assessed to 6 months postpartum. Adverse CV events were defined as CV death, aortic dissection/rupture and/or aortic intervention. Non-pregnant age-matched controls were followed over the same time period. RESULTS: Sixty-eight pregnancies were included (60 women, mean age 33 years, 48% primigravid, 49% fertility therapy, 80% structurally normal heart, 25% XO karyotype). Based on American Society of Reproductive Medicine criteria, 10 pregnancies occurred in women stratified to high-risk category. There were no CV events in the pregnant women or in the non-pregnant women with TS. Obstetric events complicated 12 (18%) pregnancies with 9 (13%) attributed to hypertensive disorder of pregnancy. Fetal events included small for gestational age neonates (18%), preterm delivery (15%) and fetal death (3%). CONCLUSIONS: This study helps to refine the approach to pregnancy in women with TS. Among women with TS without structural heart disease, pregnancy does not impose an increased risk of CV outcomes. Among women with TS with structural heart disease, the risk of pregnancy is not as prohibitive as previously described but does require ongoing evaluation.

Evolving Paradigms in the Treatment of Atrial Septal Defects With Pulmonary Arterial Hypertension.

Atrial septal defects are one of the most frequently diagnosed congenital heart defects in adulthood. The presence of concurrent moderate or severe pulmonary arterial hypertension without Eisenmenger syndrome at the time of diagnosis can make for a challenging clinical scenario. There is continually evolving literature to determine the ideal approach to this subset of patients. Here we aim to review the clinical presentation, history, medical therapy, and closure options for atrial septal defects-pulmonary arterial hypertension with predominant left-to-right shunting, in the absence of Eisenmenger syndrome.

Pulmonary vasodilators: beyond the bounds of pulmonary arterial hypertension therapy in COVID-19.

Pulmonary arterial hypertension (PAH) and novel coronavirus (SARS-CoV-2) disease COVID-19 are characterized by extensive endothelial dysfunction and inflammation leading to vascular remodeling and severe microthrombi and microvascular obliterative disease. It is hypothesized that those patients with underlying lung disease, like PAH, represent a high-risk cohort in this pandemic. However, reports of COVID-19 in this cohort of patient have been scaring and an observational survey showed that the disease was relatively well tolerated. We postulate that specific PAH vasodilator may offer some protection and/or advantage in the case of concomitant COVID-19. Here we review the literature describing mechanisms of action for each of the broad categories of PAH therapy, and offer potential hypothesis about why this therapy may impact outcomes in COVID-19.