The fatal trajectory of pulmonary COVID-19 is driven by lobular ischemia and fibrotic remodelling.

BACKGROUND: COVID-19 is characterized by a heterogeneous clinical presentation, ranging from mild symptoms to severe courses of disease. 9-20% of hospitalized patients with severe lung disease die from COVID-19 and a substantial number of survivors develop long-COVID. Our objective was to provide comprehensive insights into the pathophysiology of severe COVID-19 and to identify liquid biomarkers for disease severity and therapy response. METHODS: We studied a total of 85 lungs (n = 31 COVID autopsy samples; n = 7 influenza A autopsy samples; n = 18 interstitial lung disease explants; n = 24 healthy controls) using the highest resolution Synchrotron radiation-based hierarchical phase-contrast tomography, scanning electron microscopy of microvascular corrosion casts, immunohistochemistry, matrix-assisted laser desorption ionization mass spectrometry imaging, and analysis of mRNA expression and biological pathways. Plasma samples from all disease groups were used for liquid biomarker determination using ELISA. The anatomic/molecular data were analyzed as a function of patients' hospitalization time. FINDINGS: The observed patchy/mosaic appearance of COVID-19 in conventional lung imaging resulted from microvascular occlusion and secondary lobular ischemia. The length of hospitalization was associated with increased intussusceptive angiogenesis. This was associated with enhanced angiogenic, and fibrotic gene expression demonstrated by molecular profiling and metabolomic analysis. Increased plasma fibrosis markers correlated with their pulmonary tissue transcript levels and predicted disease severity. Plasma analysis confirmed distinct fibrosis biomarkers (TSP2, GDF15, IGFBP7, Pro-C3) that predicted the fatal trajectory in COVID-19. INTERPRETATION: Pulmonary severe COVID-19 is a consequence of secondary lobular microischemia and fibrotic remodelling, resulting in a distinctive form of fibrotic interstitial lung disease that contributes to long-COVID. FUNDING: This project was made possible by a number of funders. The full list can be found within the Declaration of interests / Acknowledgements section at the end of the manuscript.

Outcomes of patients with acute respiratory failure on veno-venous extracorporeal membrane oxygenation requiring additional circulatory support by veno-venoarterial extracorporeal membrane oxygenation.

Objective: Veno-venous (V-V) extracorporeal membrane oxygenation (ECMO) is increasingly used to support patients with severe acute respiratory distress syndrome (ARDS). In case of additional cardio-circulatory failure, some experienced centers upgrade the V-V ECMO with an additional arterial return cannula (termed V-VA ECMO). Here we analyzed short- and long-term outcome together with potential predictors of mortality. Design: Multicenter, retrospective analysis between January 2008 and September 2021. Setting: Three tertiary care ECMO centers in Germany (Hannover, Bonn) and Switzerland (Zurich). Patients: Seventy-three V-V ECMO patients with ARDS and additional acute cardio-circulatory deterioration required an upgrade to V-VA ECMO were included in this study. Measurements and main results: Fifty-three patients required an upgrade from V-V to V-VA and 20 patients were directly triple cannulated. Median (Interquartile Range) age was 49 (28-57) years and SOFA score was 14 (12-17) at V-VA ECMO upgrade. Vasoactive-inotropic score decreased from 53 (12-123) at V-VA ECMO upgrade to 9 (3-37) after 24 h of V-VA ECMO support. Weaning from V-VA and V-V ECMO was successful in 47 (64%) and 40 (55%) patients, respectively. Duration of ECMO support was 12 (6-22) days and ICU length of stay was 32 (16-46) days. Overall ICU mortality was 48% and hospital mortality 51%. Two additional patients died after hospital discharge while the remaining patients survived up to two years (with six patients being lost to follow-up). The vast majority of patients was free from higher degree persistent organ dysfunction at follow-up. A SOFA score > 14 and higher lactate concentrations at the day of V-VA upgrade were independent predictors of mortality in the multivariate regression analysis. Conclusion: In this analysis, the use of V-VA ECMO in patients with ARDS and concomitant cardiocirculatory failure was associated with a hospital survival of about 50%, and most of these patients survived up to 2 years. A SOFA score > 14 and elevated lactate levels at the day of V-VA upgrade predict unfavorable outcome.

Reduced humoral but stable cellular SARS-CoV-2-specific immunity in liver transplant recipients in the first year after COVID-19.

Mortality due to COVID-19 is not increased in immunosuppressed individuals after liver transplantation (OLT) compared to individuals without immunosuppression. Data on long-term protective immunity against SARS-CoV-2 in immunosuppressed convalescents, is limited. We prospectively measured immune responses against SARS-CoV-2 by quantifying antibodies against 4 different antigens (spike protein 1 and 2, receptor binding domain, nucleocapsid) and T cell responses by IFN-γ ELISPOT against 4 antigens (membrane, nucleocapsid, spike protein 1 and 2) in 24 OLT convalescents with immunosuppressive therapy longitudinally in the first year after COVID-19 including a booster vaccination in comparison to a matched cohort of non-immunosuppressed convalescents (non-IS-Con). Pre-pandemic OLT samples were retrieved from our prospective OLT biorepository (n = 16). No relevant T cell reactivity or immunoglobulin G (IgG) against SARS-CoV-2 were detectable in pre-pandemic samples of OLT recipients despite reactivity against endemic corona-viruses. OLT convalescents had a lower prevalence of IgG against nucleocapsid (54% vs. 90%) but not against spike protein domains (98-100% vs. 100%) after vaccination in the second half-year after COVID-19 compared to non-IS-Con. Also, concentrations of anti-nucleocapsid IgG were lower in OLT convalescents than in non-IS-Con. Concentration of IgG against spike protein domains was significantly increased by a booster vaccination in OLT convalescents. But concentration of IgG against two of three spike protein domains remains slightly lower compared to non-IS-Con finally. However, none of these differences was mirrored by the cellular immunity against SARS-CoV-2 that remained stable during the first year after COVID-19 and was not further stimulated by a corona vaccination in OLT convalescents. In conclusion, despite lower concentrations of anti-SARS-CoV-2 IgG in OLT convalescents anti-SARS-CoV-2 cellular immunity was as robust as in non-IS-Con.

Time-Dependent Molecular Motifs of Pulmonary Fibrogenesis in COVID-19.

(1) Background: In COVID-19 survivors there is an increased prevalence of pulmonary fibrosis of which the underlying molecular mechanisms are poorly understood; (2) Methods: In this multicentric study, n = 12 patients who succumbed to COVID-19 due to progressive respiratory failure were assigned to an early and late group (death within ≤7 and >7 days of hospitalization, respectively) and compared to n = 11 healthy controls; mRNA and protein expression as well as biological pathway analysis were performed to gain insights into the evolution of pulmonary fibrogenesis in COVID-19; (3) Results: Median duration of hospitalization until death was 3 (IQR25-75, 3-3.75) and 14 (12.5-14) days in the early and late group, respectively. Fifty-eight out of 770 analyzed genes showed a significantly altered expression signature in COVID-19 compared to controls in a time-dependent manner. The entire study group showed an increased expression of BST2 and IL1R1, independent of hospitalization time. In the early group there was increased activity of inflammation-related genes and pathways, while fibrosis-related genes (particularly PDGFRB) and pathways dominated in the late group; (4) Conclusions: After the first week of hospitalization, there is a shift from pro-inflammatory to fibrogenic activity in severe COVID-19. IL1R1 and PDGFRB may serve as potential therapeutic targets in future studies.

Intracranial Hemorrhages on Extracorporeal Membrane Oxygenation: Differences Between COVID-19 and Other Viral Acute Respiratory Distress Syndrome.

OBJECTIVES: Extracorporeal membrane oxygenation (ECMO) is a potentially lifesaving procedure in acute respiratory distress syndrome (ARDS) due to COVID-19. Previous studies have shown a high prevalence of clinically silent cerebral microbleeds in patients with COVID-19. Based on this fact, together with the hemotrauma and the requirement of therapeutic anticoagulation on ECMO support, we hypothesized an increased risk of intracranial hemorrhages (ICHs). We analyzed ICH occurrence rate, circumstances and clinical outcome in patients that received ECMO support due to COVID-19-induced ARDS in comparison to viral non-COVID-19-induced ARDS intracerebral hemorrhage. DESIGN: Multicenter, retrospective analysis between January 2010 and May 2021. SETTING: Three tertiary care ECMO centers in Germany and Switzerland. PATIENTS: Two-hundred ten ARDS patients on ECMO support (COVID-19, n = 142 vs viral non-COVID, n = 68). INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Evaluation of ICH occurrence rate, parameters of coagulation and anticoagulation strategies, inflammation, and ICU survival. COVID-19 and non-COVID-19 ARDS patients showed comparable disease severity regarding Sequential Organ Failure Assessment score, while the oxygenation index before ECMO cannulation was higher in the COVID group (82 vs 65 mm Hg). Overall, ICH of any severity occurred in 29 of 142 COVID-19 patients (20%) versus four of 68 patients in the control ECMO group (6%). Fifteen of those 29 ICH events in the COVID-19 group were classified as major (52%) including nine fatal cases (9/29, 31%). In the control group, there was only one major ICH event (1/4, 25%). The adjusted subhazard ratio for the occurrence of an ICH in the COVID-19 group was 5.82 (97.5% CI, 1.9-17.8; p = 0.002). The overall ICU mortality in the presence of ICH of any severity was 88%. CONCLUSIONS: This retrospective multicenter analysis showed a six-fold increased adjusted risk for ICH and a 3.5-fold increased incidence of ICH in COVID-19 patients on ECMO. Prospective studies are needed to confirm this observation and to determine whether the bleeding risk can be reduced by adjusting anticoagulation strategies.

Humoral and Cellular Immune Responses Against Severe Acute Respiratory Syndrome Coronavirus 2 Variants and Human Coronaviruses After Single BNT162b2 Vaccination.

BACKGROUND: Vaccine-induced neutralizing antibodies are key in combating the coronavirus disease 2019 (COVID-19) pandemic. However, delays of boost immunization due to limited availability of vaccines may leave individuals vulnerable to infection and prolonged or severe disease courses. The emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants of concern (VOC)-B.1.1.7 (United Kingdom), B.1.351 (South Africa), and P.1 (Brazil)-may exacerbate this issue, as the latter two are able to evade control by antibodies. METHODS: We assessed humoral and T-cell responses against SARS-CoV-2 wild-type (WT), VOC, and endemic human coronaviruses (hCoVs) that were induced after single and double vaccination with BNT162b2. RESULTS: Despite readily detectable immunoglobulin G (IgG) against the receptor-binding domain of the SARS-CoV-2 S protein at day 14 after a single vaccination, inhibition of SARS-CoV-2 S-driven host cell entry was weak and particularly low for the B.1.351 variant. Frequencies of SARS-CoV-2 WT and VOC-specific T cells were low in many vaccinees after application of a single dose and influenced by immunity against endemic hCoV. The second vaccination significantly boosted T-cell frequencies reactive for WT and B.1.1.7 and B.1.351 variants. CONCLUSIONS: These results call into question whether neutralizing antibodies significantly contribute to protection against COVID-19 upon single vaccination and suggest that cellular immunity is central for the early defenses against COVID-19.

Impact of SARS-CoV-2-Pandemic on Mental Disorders and Quality of Life in Patients With Pulmonary Arterial Hypertension.

Background/Objective: Covid-19 pandemic may affect mental health and quality of life (QoL) in patients with pulmonary arterial hypertension (PAH). We assessed changes in anxiety and depression, quality of life (QoL) and self-described impact of Covid-19 in patients with PAH during the Covid-19 pandemic. Methods: This study included 152 patients with PAH from two German referral centers. Anxiety and depression were assessed using the Hospital Anxiety and Depression Scale (HADS-A and HADS-D) at two different timepoints before and during the Covid-19 pandemic with a median of 232 days between baseline and follow-up. QoL was assessed using EQ-5D and emPHasis-10. Perceived impact of Covid-19 and related regulations and measures were assessed using a set of specific questions and statements. Results: More than two thirds of patients had an unsuspicious HADS-A and HADS-D. Median scores did not differ from baseline for both HADS-A and HADS-D (p = 0.202; p = 0.621). Overall, no significant changes in HADS-A or HADS-D categories from baseline to follow up were observed (p = 0.07; p = 0.13). QoL did not change between baseline and follow-up. The Covid-19 pandemic had little impact on access to medical care and established PAH therapy. Patients were in agreement with governmental measures and regulations and felt sufficiently safe. Conclusion: First waves of Covid-19 pandemic had little impact on anxiety, depression and QoL in patient with PAH. Established PAH therapy and access to medical care were not affected. Further studies on the impact of prolonged duration of the ongoing Covid-19 pandemic are needed.

C-reactive protein and procalcitonin for antimicrobial stewardship in COVID-19.

PURPOSE: Coronavirus disease 2019 (COVID-19) caused by severe acute respiratory coronavirus 2 (SARS-CoV-2) has spread around the world. Differentiation between pure viral COVID-19 pneumonia and secondary infection can be challenging. In patients with elevated C-reactive protein (CRP) on admission physicians often decide to prescribe antibiotic therapy. However, overuse of anti-infective therapy in the pandemic should be avoided to prevent increasing antimicrobial resistance. Procalcitonin (PCT) and CRP have proven useful in other lower respiratory tract infections and might help to differentiate between pure viral or secondary infection. METHODS: We performed a retrospective study of patients admitted with COVID-19 between 6th March and 30th October 2020. Patient background, clinical course, laboratory findings with focus on PCT and CRP levels and microbiology results were evaluated. Patients with and without secondary bacterial infection in relation to PCT and CRP were compared. Using receiver operating characteristic (ROC) analysis, the best discriminating cut-off value of PCT and CRP with the corresponding sensitivity and specificity was calculated. RESULTS: Out of 99 inpatients (52 ICU, 47 Non-ICU) with COVID-19, 32 (32%) presented with secondary bacterial infection during hospitalization. Patients with secondary bacterial infection had higher PCT (0.4 versus 0.1 ng/mL; p = 0.016) and CRP (131 versus 73 mg/L; p = 0.001) levels at admission and during the hospital stay (2.9 versus 0.1 ng/mL; p < 0.001 resp. 293 versus 94 mg/L; p < 0.001). The majority of patients on general ward had no secondary bacterial infection (93%). More than half of patients admitted to the ICU developed secondary bacterial infection (56%). ROC analysis of highest PCT resp. CRP and secondary infection yielded AUCs of 0.88 (p < 0.001) resp. 0.86 (p < 0.001) for the entire cohort. With a PCT cut-off value at 0.55 ng/mL, the sensitivity was 91% with a specificity of 81%; a CRP cut-off value at 172 mg/L yielded a sensitivity of 81% with a specificity of 76%. CONCLUSION: PCT and CRP measurement on admission and during the course of the disease in patients with COVID-19 may be helpful in identifying secondary bacterial infections and guiding the use of antibiotic therapy.

High Incidence of Epileptiform Potentials During Continuous EEG Monitoring in Critically Ill COVID-19 Patients.

Objective: To analyze continuous 1- or 2-channel electroencephalograms (EEGs) of mechanically ventilated patients with coronavirus disease 2019 (COVID-19) with regard to occurrence of epileptiform potentials. Design: Single-center retrospective analysis. Setting: Intensive care unit of Hannover Medical School, Hannover, Germany. Patients: Critically ill COVID-19 patients who underwent continuous routine EEG monitoring (EEG monitor: Narcotrend-Compact M) during sedation. Measurements and Main Results: Data from 15 COVID-19 patients (11 men, four women; age: 19-75 years) were evaluated. Epileptiform potentials occurred in 10 of 15 patients (66.7%). Conclusions: The results of the evaluation regarding the occurrence of epileptiform potentials show that there is an unusually high percentage of cerebral involvement in patients with severe COVID-19. EEG monitoring can be used in COVID-19 patients to detect epileptiform potentials.

Circulating cardiovascular microRNAs in critically ill COVID-19 patients.

AIMS: Coronavirus disease 2019 (COVID-19) is a still growing pandemic, causing many deaths and socio-economic damage. Elevated expression of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) entry receptor angiotensin-converting enzyme 2 on cardiac cells of patients with heart diseases may be related to cardiovascular burden. We have thus analysed cardiovascular and inflammatory microRNAs (miRs), sensitive markers of cardiovascular damage, in critically ill, ventilated patients with COVID-19 or influenza-associated acute respiratory distress syndrome (Influenza-ARDS) admitted to the intensive care unit and healthy controls. METHODS AND RESULTS: Circulating miRs (miR-21, miR-126, miR-155, miR-208a, and miR-499) were analysed in a discovery cohort consisting of patients with mechanically-ventilated COVID-19 (n = 18) and healthy controls (n = 15). A validation study was performed in an independent cohort of mechanically-ventilated COVID-19 patients (n = 20), Influenza-ARDS patients (n = 13) and healthy controls (n = 32). In both cohorts, RNA was isolated from serum and cardiovascular disease/inflammatory-relevant miR concentrations were measured by miR-specific TaqMan PCR analyses. In both the discovery and the validation cohort, serum concentration of miR-21, miR-155, miR-208a and miR-499 were significantly increased in COVID-19 patients compared to healthy controls. Calculating the area under the curve using receiver operating characteristic analysis miR-155, miR-208a and miR-499 showed a clear distinction between COVID-19 and Influenza-ARDS patients. CONCLUSION: In this exploratory study, inflammation and cardiac myocyte-specific miRs were upregulated in critically ill COVID-19 patients. Importantly, miR profiles were able to differentiate between severely ill, mechanically-ventilated Influenza-ARDS and COVID-19 patients, indicating a rather specific response and cardiac involvement of COVID-19.

COVID-19 immune signatures reveal stable antiviral T cell function despite declining humoral responses.

Cellular and humoral immunity to SARS-CoV-2 is critical to control primary infection and correlates with severity of disease. The role of SARS-CoV-2-specific T cell immunity, its relationship to antibodies, and pre-existing immunity against endemic coronaviruses (huCoV), which has been hypothesized to be protective, were investigated in 82 healthy donors (HDs), 204 recovered (RCs), and 92 active COVID-19 patients (ACs). ACs had high amounts of anti-SARS-CoV-2 nucleocapsid and spike IgG but lymphopenia and overall reduced antiviral T cell responses due to the inflammatory milieu, expression of inhibitory molecules (PD-1, Tim-3) as well as effector caspase-3, -7, and -8 activity in T cells. SARS-CoV-2-specific T cell immunity conferred by polyfunctional, mainly interferon-γ-secreting CD4+ T cells remained stable throughout convalescence, whereas humoral responses declined. Immune responses toward huCoV in RCs with mild disease and strong cellular SARS-CoV-2 T cell reactivity imply a protective role of pre-existing immunity against huCoV.

Immunoglobulin deficiency as an indicator of disease severity in patients with COVID-19.

Despite the pandemic status of COVID-19, there is limited information about host risk factors and treatment beyond supportive care. Immunoglobulin G (IgG) could be a potential treatment target. Our aim was to determine the incidence of IgG deficiency and associated risk factors in a cohort of 62 critically ill patients with COVID-19 admitted to two German ICUs (72.6% male, median age: 61 yr). Thirteen (21.0%) of the patients displayed IgG deficiency (IgG < 7 g/L) at baseline (predominant for the IgG1, IgG2, and IgG4 subclasses). Patients who were IgG-deficient had worse measures of clinical disease severity than those with normal IgG levels (shorter duration from disease onset to ICU admission, lower ratio of [Formula: see text] to [Formula: see text], higher Sequential Organ Failure Assessment score, and higher levels of ferritin, neutrophil-to-lymphocyte ratio, and serum creatinine). Patients who were IgG-deficient were also more likely to have sustained lower levels of lymphocyte counts and higher levels of ferritin throughout the hospital stay. Furthermore, patients who were IgG-deficient compared with those with normal IgG levels displayed higher rates of acute kidney injury (76.9% vs. 26.5%; P = 0.001) and death (46.2% vs. 14.3%; P = 0.012), longer ICU [28 (6-48) vs. 12 (3-18) days; P = 0.012] and hospital length of stay [30 (22-50) vs. 18 (9-24) days; P = 0.004]. Univariable logistic regression showed increasing odds of 90-day overall mortality associated with IgG-deficiency (odds ratio 5.14, 95% confidence interval 1.3-19.9; P = 0.018). IgG deficiency might be common in patients with COVID-19 who are critically ill, and warrants investigation as both a marker of disease severity as well as a potential therapeutic target.

Low serum neutralizing anti-SARS-CoV-2 S antibody levels in mildly affected COVID-19 convalescent patients revealed by two different detection methods.

Neutralizing antibodies targeting the receptor-binding domain (RBD) of the SARS-CoV-2 spike (S) block severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) entry into cells via surface-expressed angiotensin-converting enzyme 2 (ACE2). We used a surrogate virus neutralization test (sVNT) and SARS-CoV-2 S protein-pseudotyped vesicular stomatitis virus (VSV) vector-based neutralization assay (pVNT) to assess the degree to which serum antibodies from coronavirus disease 2019 (COVID-19) convalescent patients interfere with the binding of SARS-CoV-2 S to ACE2. Both tests revealed neutralizing anti-SARS-CoV-2 S antibodies in the sera of ~90% of mildly and 100% of severely affected COVID-19 convalescent patients. Importantly, sVNT and pVNT results correlated strongly with each other and to the levels of anti-SARS-CoV-2 S1 IgG and IgA antibodies. Moreover, levels of neutralizing antibodies correlated with the duration and severity of clinical symptoms but not with patient age. Compared to pVNT, sVNT is less sophisticated and does not require any biosafety labs. Since this assay is also much faster and cheaper, sVNT will not only be important for evaluating the prevalence of neutralizing antibodies in a population but also for identifying promising plasma donors for successful passive antibody therapy.