Transmural myocardial repair with engineered heart muscle in a rat model of heterotopic heart transplantation - A proof-of-concept study.

Engineered heart muscle (EHM) can be implanted epicardially to remuscularize the failing heart. In case of a severely scarred ventricle, excision of scar followed by transmural heart wall replacement may be a more desirable application. Accordingly, we tested the hypothesis that allograft (rat) and xenograft (human) EHM can also be administered as transmural heart wall replacement in a heterotopic, volume-loaded heart transplantation model. We first established a novel rat model model to test surgical transmural left heart wall repair. Subsequently and in continuation of our previous allograft studies, we tested outcome after implantation of contractile engineered heart muscle (EHM) and non-contractile engineered connective tissue (ECT) as well as engineered mesenchymal tissue (EMT) allografts as transmural heart wall replacement. Finally, proof-of-concept for the application of human EHM was obtained in an athymic nude rat model. Only in case of EHM implantation, remuscularization of the surgically created transmural defect was observed with palpable graft vascularization. Taken together, feasibility of transmural heart repair using bioengineered myocardial grafts could be demonstrated in a novel rat model of heterotopic heart transplantation.

ACE2 polymorphism and susceptibility for SARS-CoV-2 infection and severity of COVID-19.

OBJECTIVES: The RNA virus severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is responsible for coronavirus disease 2019 (COVID-19). Cell entry is mediated by the human angiotensin-converting enzyme II (ACE2). ACE2 and its close homolog angiotensin-converting enzyme I (ACE) are currently discussed candidate genes, in which single-nucleotide polymorphisms (SNPs) could alter binding or entry of SARS-CoV-2 and enhance tissue damage in the lung or other organs. This could increase the susceptibility for SARS-CoV-2 infection and the severity of COVID-19. PATIENTS AND METHODS: We performed genotyping of SNPs in the genes ACE2 and ACE in 297 SARS-CoV-2-positive and 253 SARS-CoV-2-negative tested patients. We analyzed the association of the SNPs with susceptibility for SARS-CoV-2 infection and the severity of COVID-19. RESULTS: SARS-CoV-2-positive and SARS-CoV-2-negative patients did not differ regarding demographics and clinical characteristics. For ACE2 rs2285666, the GG genotype or G-allele was significantly associated with an almost two-fold increased SARS-CoV-2 infection risk and a three-fold increased risk to develop serious disease or COVID-19 fatality. In contrast, the ACE polymorphism was not related to infection risk or severity of disease. In a multivariable analysis, the ACE2 rs2285666 G-allele remained as an independent risk factor for serious disease besides the known risk factors male gender and cardiovascular disease. CONCLUSIONS: In summary, our report appears to be the first showing that a common ACE2 polymorphism impacts the risk for SARS-CoV-2 infection and the course of COVID-19 independently from previously described risk factors.

Broncho-alveolar lavage in patients with acute respiratory distress syndrome due to COVID-19.

As data about microbiological testing and the cellular composition of the broncho-alveolar lavage (BAL) fluid in patients ventilated due to coronavirus disease 2019 (COVID-19) are lacking, this was investigated in a retrospective analysis (n = 58). Co-infection with pathogens was detected in 31 patients, whereas the analysis of BAL cellularity showed an increased total cell count and an alveolitis dominated by neutrophils. None of the physicians performing bronchoscopies in COVID-19 patients had serological evidence of severe acute respiratory syndrome coronavirus 2 infection.

Epigenetic Clocks Are Not Accelerated in COVID-19 Patients.

Age is a major risk factor for severe outcome of the 2019 coronavirus disease (COVID-19). In this study, we followed the hypothesis that particularly patients with accelerated epigenetic age are affected by severe outcomes of COVID-19. We investigated various DNA methylation datasets of blood samples with epigenetic aging signatures and performed targeted bisulfite amplicon sequencing. Overall, epigenetic clocks closely correlated with the chronological age of patients, either with or without acute respiratory distress syndrome. Furthermore, lymphocytes did not reveal significantly accelerated telomere attrition. Thus, these biomarkers cannot reliably predict higher risk for severe COVID-19 infection in elderly patients.

Defined Engineered Human Myocardium With Advanced Maturation for Applications in Heart Failure Modeling and Repair.

BACKGROUND: Advancing structural and functional maturation of stem cell-derived cardiomyocytes remains a key challenge for applications in disease modeling, drug screening, and heart repair. Here, we sought to advance cardiomyocyte maturation in engineered human myocardium (EHM) toward an adult phenotype under defined conditions. METHODS: We systematically investigated cell composition, matrix, and media conditions to generate EHM from embryonic and induced pluripotent stem cell-derived cardiomyocytes and fibroblasts with organotypic functionality under serum-free conditions. We used morphological, functional, and transcriptome analyses to benchmark maturation of EHM. RESULTS: EHM demonstrated important structural and functional properties of postnatal myocardium, including: (1) rod-shaped cardiomyocytes with M bands assembled as a functional syncytium; (2) systolic twitch forces at a similar level as observed in bona fide postnatal myocardium; (3) a positive force-frequency response; (4) inotropic responses to ß-adrenergic stimulation mediated via canonical ß1- and ß2-adrenoceptor signaling pathways; and (5) evidence for advanced molecular maturation by transcriptome profiling. EHM responded to chronic catecholamine toxicity with contractile dysfunction, cardiomyocyte hypertrophy, cardiomyocyte death, and N-terminal pro B-type natriuretic peptide release; all are classical hallmarks of heart failure. In addition, we demonstrate the scalability of EHM according to anticipated clinical demands for cardiac repair. CONCLUSIONS: We provide proof-of-concept for a universally applicable technology for the engineering of macroscale human myocardium for disease modeling and heart repair from embryonic and induced pluripotent stem cell-derived cardiomyocytes under defined, serum-free conditions.

Cardiopulmonary work up of patients with and without fatigue 6 months after COVID-19.

The pathogenesis of long-Covid symptoms remains incompletely understood. Therefore, we aimed to determine cardiopulmonary limitations 6 months after surviving COVID-19 using pulmonary function tests, echocardiographic studies to the point of analysis of global-longitudinal-strain (GLS), which describes the cycling myocardium deformation and provides better data on left ventricular (LV) dysfunction than LV ejection fraction (LVEF), and validated questionnaires. Overall, 60 consecutive hospitalized patients were included (61 ± 2 years, 40% treated in the ICU). At follow-up (194 ± 3 days after discharge), fatigue was the most prevalent symptom (28%). Patients with fatigue were more symptomatic overall and characterized by worse quality of life (QoL) scores compared to patients without fatigue (all p < 0.05), mainly due to limited mobility and high symptom burden. While PFT variables and LVEF were normal in the vast majority of patients (LVEF = 52% (45-52%)), GLS was significantly reduced (- 15% (- 18 to - 14%)). However, GLS values were not different between patients with and without fatigue. In conclusion, fatigue was the most prevalent long-Covid symptom in our cohort, which was associated with worse QoL mainly due to limited mobility and the high burden of concomitant symptoms. Patients showed a subtle myocardial dysfunction 6 months after surviving COVID-19, but this did not relate to the presence of fatigue.

Glycaemic variability is associated with all-cause mortality in COVID-19 patients with ARDS, a retrospective subcohort study.

There is high mortality among intensive care unit (ICU) patients with acute respiratory distress syndrome (ARDS) caused by coronavirus disease (COVID-19). Important factors for COVID-19 mortality are diabetes status and elevated fasting plasma glucose (FPG). However, the effect of glycaemic variability on survival has not been explored in patients with COVID-19 and ARDS. This single-centre cohort study compared several metrics of glycaemic variability for goodness-of-fit in patients requiring mechanical ventilation due to COVID-19 ARDS in the ICU at University Hospital Aachen, Germany. 106 patients had moderate to severe ARDS (P/F ratio median [IQR]: 112 [87-148] mmHg). Continuous HRs showed a proportional increase in mortality risk with daily glycaemic variability (DGV). Multivariable unadjusted and adjusted Cox-models showed a statistically significant difference in mortality for DGV (HR: 1.02, (P) < 0.001, LR(P) < 0.001; HR: 1.016, (P) = 0.001, LR(P) < 0.001, respectively). Kaplan-Meier estimators yielded a shorter median survival (25 vs. 87 days) and a higher likelihood of death (75% vs. 31%) in patients with DGV ≥ 25.5 mg/dl (P < 0.0001). High glycaemic variability during ICU admission is associated with significant increase in all-cause mortality for patients admitted with COVID-19 ARDS to the ICU. This effect persisted even after adjustment for clinically predetermined confounders, including diabetes, median procalcitonin and FPG.

Dissecting CD8+ T cell pathology of severe SARS-CoV-2 infection by single-cell immunoprofiling.

Introduction: SARS-CoV-2 infection results in varying disease severity, ranging from asymptomatic infection to severe illness. A detailed understanding of the immune response to SARS-CoV-2 is critical to unravel the causative factors underlying differences in disease severity and to develop optimal vaccines against new SARS-CoV-2 variants. Methods: We combined single-cell RNA and T cell receptor sequencing with CITE-seq antibodies to characterize the CD8+ T cell response to SARS-CoV-2 infection at high resolution and compared responses between mild and severe COVID-19. Results: We observed increased CD8+ T cell exhaustion in severe SARS-CoV-2 infection and identified a population of NK-like, terminally differentiated CD8+ effector T cells characterized by expression of FCGR3A (encoding CD16). Further characterization of NK-like CD8+ T cells revealed heterogeneity among CD16+ NK-like CD8+ T cells and profound differences in cytotoxicity, exhaustion, and NK-like differentiation between mild and severe disease conditions. Discussion: We propose a model in which differences in the surrounding inflammatory milieu lead to crucial differences in NK-like differentiation of CD8+ effector T cells, ultimately resulting in the appearance of NK-like CD8+ T cell populations of different functionality and pathogenicity. Our in-depth characterization of the CD8+ T cell-mediated response to SARS-CoV-2 infection provides a basis for further investigation of the importance of NK-like CD8+ T cells in COVID-19 severity.

Clinical course of COVID-19 patients needing supplemental oxygen outside the intensive care unit.

Patients suffering from CVOID-19 mostly experience a benign course of the disease. Approximately 14% of SARS-CoV2 infected patients are admitted to a hospital. Cohorts exhibiting severe lung failure in the form of acute respiratory distress syndrome (ARDS) have been well characterized. Patients without ARDS but in need of supplementary oxygen have received much less attention. This study describes the diagnosis, symptoms, treatment and outcomes of hospitalized patients with COVID-19 needing oxygen support during their stay on regular ward. All 133 patients admitted to the RWTH Aachen university hospital with the diagnosis of COVID-19 were included in an observational registry. Clinical data sets were extracted from the hospital information system. This analysis includes all 57 patients requiring supplemental oxygen not admitted to the ICU. 57 patients needing supplemental oxygen and being treated outside the ICU were analyzed. Patients exhibited the typical set of symptoms for COVID-19. Of note, hypoxic patients mostly did not suffer from clinically relevant dyspnea despite oxygen saturations below 92%. Patients had fever for 7 [2-11] days and needed supplemental oxygen for 8 [5-13] days resulting in an overall hospitalization time of 12 [7-20] days. In addition, patients had persisting systemic inflammation with CRP levels remaining elevated until discharge or death. This description of COVID-19 patients requiring oxygen therapy should be taken into account when planning treatment capacity. Patients on oxygen need long-term inpatient care.

Elevated serum SDMA and ADMA at hospital admission predict in-hospital mortality of COVID-19 patients.

COVID-19 is a disease with a variable clinical course ranging from mild symptoms to critical illness, organ failure, and death. Prospective biomarkers may help to predict the severity of an individual's clinical course and mortality risk. We analyzed asymmetric (ADMA) and symmetric dimethylarginine (SDMA) in blood samples from 31 patients hospitalized for COVID-19. We calculated associations of ADMA and SDMA with mortality and organ failure, and we developed a predictive algorithm based upon these biomarkers to predict mortality risk. Nine patients (29%) experienced in-hospital death. SDMA and ADMA serum concentrations were significantly higher at admission in COVID-19 patients who died than in survivors. Cut-offs of 0.90 µmol/L for SDMA (AUC, 0.904, p = 0.0005) and 0.66 µmol/L for ADMA (AUC, 0.874, p = 0.0013) were found in ROC analyses to best discriminate both subgroups of patients. Hazard ratio for in-hospital mortality was 12.2 (95% CI: 2.2-31.2) for SDMA and 6.3 (1.1-14.7) for ADMA above cut-off. Sequential analysis of both biomarkers allowed discriminating a high-risk group (87.5% mortality) from an intermediate-risk group (25% mortality) and a low-risk group (0% mortality). Elevated circulating concentrations of SDMA and ADMA may help to better identify COVID-19 patients with a high risk of in-hospital mortality.

Neurological symptoms in COVID-19: a cross-sectional monocentric study of hospitalized patients.

BACKGROUND: The SARS-Coronavirus-2 (SARS-CoV-2) invades the respiratory system, causing acute and sometimes severe pulmonary symptoms, but turned out to also act multisystematically with substantial impact on the brain. A growing number of studies suggests a diverse spectrum of neurological manifestations. To investigate the spectrum of symptoms, we here describe the neurological manifestations and complications of patients with proven SARS-CoV-2 infection who have been hospitalized at the RWTH University Hospital Aachen, Germany. METHODS: Between March and September 2020, we evaluated common symptoms, clinical characteristics, laboratory (including cerebrospinal fluid (CSF) analysis), radiological, and electroencephalography (EEG) data from 53 patients admitted with a positive SARS-CoV-2 polymerase chain reaction (PCR). We used the Montreal Cognitive Assessment Test (MoCA) to screen for cognitive impairment, when feasible. We compared critically ill and non-critically ill patients categorized according to the presence of Acute Respiratory Distress Syndrome (ARDS). RESULTS: Major clinical neurological features of hospitalized COVID-19 patients were coordination deficits (74%), cognitive impairment (61.5%), paresis (47%), abnormal reflex status (45%), sensory abnormalities (45%), general muscle weakness and pain (32%), hyposmia (26%), and headache (21%). Patients with ARDS were more severely affected than non-ADRS patients. 29.6% of patients with ARDS presented with subarachnoid bleedings, and 11.1% showed ischemic stroke associated with SARS-CoV-2 infection. Cognitive deficits mainly affected executive functions, attention, language, and delayed memory recall. We obtained cerebrospinal fluid (CSF) by lumbar puncture in nine of the 53 patients, none of which had a positive SARS-CoV-2 PCR. CONCLUSIONS: In line with previous findings, our results provide evidence for a range of SARS-CoV-2-associated neurological manifestations. 26% of patients reported hyposmia, emphasizing the neuro-invasive potential of SARS-CoV-2, which can enter the olfactory bulb. It can therefore be speculated that neurological manifestations may be caused by direct invasion of the virus in the CNS; however, PCR did not reveal positive intrathecal SARS-CoV-2. Therefore, we hypothesize it is more likely that the para-infectious severe pro-inflammatory impact of COVID-19 is responsible for the neurological deficits including cognitive impairment. Future studies with comprehensive longitudinal assessment of neurological deficits are required to determine potential long-term complications of COVID-19.

Six Months Follow-Up of Patients with Invasive Mechanical Ventilation due to COVID-19 Related ARDS.

Although patients who recovered from acute coronavirus disease 2019 (COVID-19) may have prolonged disabilities, follow-up data of those who have survived COVID-19 related acute respiratory distress syndrome (ARDS) is still very scarce. Therefore, COVID-19-ARDS survivors requiring invasive mechanical ventilation (IMV) were followed six months after discharge. Pulmonary function tests (PFTs), 6-min walk test (6MWT) and echocardiography were performed. Quality of life (QoL), depression and anxiety were assessed using validated questionnaires. Patients were compared based on respiratory mechanics and CT-phenotype during intensive care unit (ICU) stay. Eighteen patients were included (61 ± 7 years; ICU-stay: 34 ± 16 days; IMV: 30 ± 15 days). At follow-up (197 ± 15 days after discharge), PFTs did not reveal significant limitations (VC: 92 ± 16%; FEV1: 92 ± 20%; DLco/VA: 81 ± 16%). Cardiac systolic function was normal in all patients, but 50% of them had diastolic dysfunction. 6MWT was under the lower limit of normal in only two patients. Eight patients (44%) reported tiredness, six (33%) suffered from fatigue and one patient (6%) had depression and anxiety. Surprisingly, patients with worse respiratory mechanics during IMV reported fewer symptoms and less exertional dyspnea at follow-up. In conclusion, patients with COVID-19-ARDS have the possibility to fully recover regarding pulmonary function and exercise capacity, which seems to be independent of disease severity during ICU stay.

Early risk markers for severe clinical course and fatal outcome in German patients with COVID-19.

BACKGROUND: Some patients with Corona Virus Disease 2019 (COVID-19) develop a severe clinical course with acute respiratory distress syndrome (ARDS) and fatal outcome. Clinical manifestations and biomarkers in early stages of disease with relevant predictive impact for outcomes remain largely unexplored. We aimed to identify parameters which are significantly different between subgroups. DESIGN: 125 patients with COVID-19 were analysed. Patients with ARDS (N = 59) or non-ARDS (N = 66) were compared, as well as fatal outcome versus survival in the two groups. KEY RESULTS: ARDS and non-ARDS patients did not differ with respect to comorbidities or medication on developing a fatal outcome versus survival. Body mass index was higher in patients with ARDS versus non-ARDS (p = 0.01), but not different within the groups in survivors versus non-survivors. Interleukin-6 levels on admission were higher in patients with ARDS compared to non-ARDS as well as in patients with fatal outcome versus survivors, whereas lymphocyte levels were lower in the different subgroups (all p<0.05). There was a highly significant 3.5-fold difference in fever load in non-survivors compared to survivors (p<0.0001). Extrapulmonary viral spread was detected more often in patients with fatal outcome compared to survivors (P = 0.01). Further the detection of SARS-CoV-2 in serum showed a significantly more severe course and an increased risk of death (both p<0.05). CONCLUSIONS: We have identified early risk markers for a severe clinical course, like ARDS or fatal outcome. This data might help develop a strategy to address new therapeutic options early in patients with COVID-19 and at high risk for fatal outcome.

Follow up of patients with severe coronavirus disease 2019 (COVID-19): Pulmonary and extrapulmonary disease sequelae.

BACKGROUND: Since December 2019 the novel coronavirus disease 2019 (COVID-19) has been burdening all health systems worldwide. However, pulmonary and extrapulmonary sequelae of COVID-19 after recovery from the acute disease are unknown. MATERIAL AND METHODS: Hospitalized COVID-19 patients not requiring mechanical ventilation were included and followed 6 weeks after discharge. Body plethysmography, lung diffusion capacity (DLco), blood gas analysis (ABG), 6-min walk test (6MWT), echocardiography, and laboratory tests were performed. Quality of life (QoL), depression, and anxiety were assessed using validated questionnaires. RESULTS: 33 patients with severe disease were included. Patients were discharged without prophylactic anticoagulation. At follow-up there were no thromboembolic complications in any patient. 11 patients (33%) had dyspnea, 11 (33%) had cough, and 15 (45%) suffered from symptoms of fatigue. Pulmonary function tests including ABG did not reveal any limitations (TLC: median=94% of predicted {IQR:85-105}; VC: 93% {78-101}; FEV1: 95% {72-103}; FEV1/FVC 79% {76-85}; PaO2: 72 mmHg {67-79}; PaCO2: 38 mmHg {35-38}), except for slightly reduced DLco (77% {69-95}). There were no echocardiographic impairments. 6MWT distance was reduced in most patients without oxygen desaturation. According to standardized questionnaires, patients suffered from reduced QoL, mainly due to decreased mobility (SGRQ activity score: 54 {19-78}). There were no indicators for depression or anxiety (PHQ-9: 7 {4-11}, GAD-7: 4 {1-9}, respectively). CONCLUSIONS: Hospitalized patients with severe COVID-19, who did not require mechanical ventilation, are unlikely to develop pulmonary long-term impairments, thromboembolic complications or cardiac impairments after discharge but frequently suffer from symptoms of fatigue.

The Characteristics of 50 Hospitalized COVID-19 Patients With and Without ARDS.

BACKGROUND: The type of pneumonia (coronavirus disease 2019, COVID-19) that is caused by the new coronavirus (severe acute respiratory syndrome coronavirus 2, SARS-CoV-2) is now spreading across the world in a pandemic. Many patients with COVID-19 were admitted to the University Hospital Aachen during an outbreak that first struck the Heinsberg district in February 2020. METHODS: A comparative presentation of the clinical features of the first 50 COVID-19 patients with and without acute respiratory distress syndrome (ARDS) who were hospitalized in the University Hospital Aachen. RESULTS: 24 intubated patients were treated in the intensive care unit for ARDS of varying degrees of severity, while 26 patients who were breathing spontaneously without ARDS, but nevertheless needed supplemental oxygen, were treated in a separate isolation ward. The median age of the patients was 65 (IQR 58-76). The median latency from symptom onset to hospitalization was four days (IQR 1-8). Patients with ARDS had preexisting respiratory diseases more commonly than patients without ARDS (58% [95% confidence interval: 39; 76] versus 42% [26; 61]) and were more commonly overweight or obese (83% [64; 93] versus 42% [26; 61]). The two groups did not differ in viral burden but displayed significant differences in laboratory findings: ARDS patients had persistently elevated values for leukocytes, interleukin-6, lactate dehydrogenase, creatine kinase, and D-dimers over the period of observation. Patients without ARDS had persistently elevated inflammatory parameters and fever for at least one week, with an accompanying need for supplemental oxygen. Three of the patients with ARDS died of multiorgan failure, while four in the non-ARDS group died of respiratory insufficiency. CONCLUSION: This initial description of a cohort of COVID-19 patients with and without ARDS in Germany reveals that those with ARDS more commonly have preexisting respiratory diseases and obesity, as well as persistently elevated inflammatory markers. COVID-19 patients without ARDS may likewise require prolonged hospitalization because of persistently elevated inflammatory values with a simultaneous need for supplemental oxygen.