Bioactive adrenomedullin and interleukin-6 in COVID-19: potential biomarkers of acute kidney injury and critical illness.

BACKGROUND: The aim of this study was to investigate whether bioactive adrenomedullin (bio-ADM) and interleukin-6 (IL-6) are related to acute kidney injury (AKI) and severe illness in COVID-19 patients. METHODS: 153 patients with COVID-19 admitted to the emergency department (ED) were included. Blood samples were collected from each patient at admission. Bio-ADM and IL-6, as well as DPP3 and routinely measured markers were evaluated regarding the endpoints AKI (22/128 hospitalized patients) and a composite endpoint of admission to intensive care unit and/or in-hospital death (n = 26/153 patients). RESULTS: Bio-ADM and IL-6 were significantly elevated in COVID-19 patients with AKI compared to COVID-19 patients without AKI (each p < 0.001). According to ROC analyses IL-6 and bio-ADM had the largest AUC (0.84 and 0.81) regarding the detection of AKI. Furthermore, bio-ADM and IL-6 were significantly elevated in COVID-19 patients reaching the composite endpoint (each p < 0.001). Regarding the composite endpoint ROC analysis showed an AUC of 0.89 for IL-6 and 0.83 for bio-ADM in COVID-19 patients. In the multivariable logistic model bio-ADM and IL-6 presented as independent significant predictors regarding both endpoints AKI and the composite endpoint in COVID-19 patients (as well as creatinine regarding the composite endpoint; each p < 0.05), opposite to leukocytes, C-reactive protein (CRP) and dipeptidyl peptidase 3 (DPP3; each p = n.s.). CONCLUSION: Elevated levels of bio-ADM and IL-6 are associated with AKI and critical illness in patients with COVID-19. Therefore, both biomarkers may be potential tools in risk stratification in COVID-19 patients at presentation in the ED.

Dipeptidyl-peptidase 3 and IL-6: potential biomarkers for diagnostics in COVID-19 and association with pulmonary infiltrates.

Coronavirus SARS-CoV-2 spread worldwide, causing a respiratory disease known as COVID-19. The aim of the present study was to examine whether Dipeptidyl-peptidase 3 (DPP3) and the inflammatory biomarkers IL-6, CRP, and leucocytes are associated with COVID-19 and able to predict the severity of pulmonary infiltrates in COVID-19 patients versus non-COVID-19 patients. 114 COVID-19 patients and 35 patients with respiratory infections other than SARS-CoV-2 were included in our prospective observational study. Blood samples were collected at presentation to the emergency department. 102 COVID-19 patients and 28 non-COVID-19 patients received CT imaging (19 outpatients did not receive CT imaging). If CT imaging was available, artificial intelligence software (CT Pneumonia Analysis) was used to quantify pulmonary infiltrates. According to the median of infiltrate (14.45%), patients who obtained quantitative CT analysis were divided into two groups (> median: 55 COVID-19 and nine non-COVID-19, ≤ median: 47 COVID-19 and 19 non-COVID-19). DPP3 was significantly elevated in COVID-19 patients (median 20.85 ng/ml, 95% CI 18.34-24.40 ng/ml), as opposed to those without SARS-CoV-2 (median 13.80 ng/ml, 95% CI 11.30-17.65 ng/ml; p < 0.001, AUC = 0.72), opposite to IL-6, CRP (each p = n.s.) and leucocytes (p < 0.05, but lower levels in COVID-19 patients). Regarding binary logistic regression analysis, higher DPP3 concentrations (OR = 1.12, p < 0.001) and lower leucocytes counts (OR = 0.76, p < 0.001) were identified as significant and independent predictors of SARS-CoV-2 infection, as opposed to IL-6 and CRP (each p = n.s.). IL-6 was significantly increased in patients with infiltrate above the median compared to infiltrate below the median both in COVID-19 (p < 0.001, AUC = 0.78) and in non-COVID-19 (p < 0.05, AUC = 0.81). CRP, DPP3, and leucocytes were increased in COVID-19 patients with infiltrate above median (each p < 0.05, AUC: CRP 0.82, DPP3 0.70, leucocytes 0.67) compared to infiltrate below median, opposite to non-COVID-19 (each p = n.s.). Regarding multiple linear regression analysis in COVID-19, CRP, IL-6, and leucocytes (each p < 0.05) were associated with the degree of pulmonary infiltrates, as opposed to DPP3 (p = n.s.). DPP3 showed the potential to be a COVID-19-specific biomarker. IL-6 might serve as a prognostic marker to assess the extent of pulmonary infiltrates in respiratory patients.

Urinary N-Terminal Pro-Brain Natriuretic Peptide Predicts Acute Kidney Injury and Severe Disease in COVID-19.

INTRODUCTION: The ongoing COVID-19 pandemic is placing an extraordinary burden on our health care system with its limited resources. Accurate triage of patients is necessary to ensure medical care for those most severely affected. In this regard, biomarkers could contribute to risk evaluation. The aim of this prospective observational clinical study was to assess the relationship between urinary N-terminal pro-brain natriuretic peptide (NT-proBNP) and acute kidney injury (AKI) as well as severe disease in patients with COVID-19. METHODS: 125 patients treated with an acute respiratory infection in the emergency department of the University Hospital Regensburg were analyzed. These patients were divided into a COVID-19 cohort (n = 91) and a cohort with infections not caused by severe acute respiratory syndrome-coronavirus-2 (n = 34). NT-proBNP was determined from serum and fresh urine samples collected in the emergency department. Clinical endpoints were the development of AKI and a composite one consisting of AKI, intensive care unit admission, and in-hospital death. RESULTS: 11 (12.1%) COVID-19 patients developed AKI during hospitalization, whereas 15 (16.5%) reached the composite endpoint. Urinary NT-proBNP was significantly elevated in COVID-19 patients who suffered AKI or reached the composite endpoint (each p < 0.005). In a multivariate regression analysis adjusted for age, chronic kidney disease, chronic heart failure, and arterial hypertension, urinary NT-proBNP was identified as independent predictor of AKI (p = 0.017, OR = 3.91 [CI: 1.28-11.97] per standard deviation [SD]), as well as of the composite endpoint (p = 0.026, OR 2.66 [CI: 1.13-6.28] per SD). CONCLUSION: Urinary NT-proBNP might help identify patients at risk for AKI and severe disease progression in COVID-19.

[Low incidence of SARS-CoV-2 infections in healthcare workers at a tertiary care hospital : Results of a prospective serological cohort study of the first and second COVID­19 pandemic wave]. / Niedrige Inzidenz von SARS-CoV­2-Infektionen bei Krankenhausmitarbeitern eines Maximalversorgers : Ergebnisse einer prospektiven serologischen Kohortenstudie der ersten und zweiten COVID­19-Welle.

BACKGROUND: Healthcare workers caring for coronavirus disease 2019 (COVID­19) patients are at an increased risk for a severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. The aim of this seroepidemiological study was to evaluate the risk of infection for employees at a tertiary care hospital. METHODS: Serological tests for antibodies against SARS-CoV­2 were carried out in a prospective cohort of employees directly involved in the care of COVID­19 patients every 2 weeks from March to July 2020 (1st wave). Antibody status was examined again between December 2020 and February 2021 (2nd wave). RESULTS: The seroprevalence of antibodies against SARS-CoV­2 was 5.1% at the end of the study in February 2021. The cumulative incidence was 3.9% after a median observation period of 261 days. CONCLUSION: We observed a low risk of SARS-CoV­2 infection comparable to that of the general population in the examined cohort of healthcare workers involved in the acute care of COVID­19 patients under the applied hygiene and protective measures.

Cardiac Fibrosis Is a Risk Factor for Severe COVID-19.

Increased left ventricular fibrosis has been reported in patients hospitalized with coronavirus disease 2019 (COVID-19). It is unclear whether this fibrosis is a consequence of severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) infection or a risk factor for severe disease progression. We observed increased fibrosis in the left ventricular myocardium of deceased COVID-19 patients, compared with matched controls. We also detected increased mRNA levels of soluble interleukin-1 receptor-like 1 (sIL1-RL1) and transforming growth factor ß1 (TGF-ß1) in the left ventricular myocardium of deceased COVID-19 patients. Biochemical analysis of blood sampled from patients admitted to the emergency department (ED) with COVID-19 revealed highly elevated levels of TGF-ß1 mRNA in these patients compared to controls. Left ventricular strain measured by echocardiography as a marker of pre-existing cardiac fibrosis correlated strongly with blood TGF-ß1 mRNA levels and predicted disease severity in COVID-19 patients. In the left ventricular myocardium and lungs of COVID-19 patients, we found increased neuropilin-1 (NRP-1) RNA levels, which correlated strongly with the prevalence of pulmonary SARS-CoV-2 nucleocapsid. Cardiac and pulmonary fibrosis may therefore predispose these patients to increased cellular viral entry in the lung, which may explain the worse clinical outcome observed in our cohort. Our study demonstrates that patients at risk of clinical deterioration can be identified early by echocardiographic strain analysis and quantification of blood TGF-ß1 mRNA performed at the time of first medical contact.

Kidney injury molecule-1: potential biomarker of acute kidney injury and disease severity in patients with COVID-19.

AIMS: The aim of the current study was to evaluate whether tubular markers kidney injury molecule-1 (KIM-1) and N-acetyl-ß-glucosaminidase (NAG) are related to acute kidney injury (AKI) and severe disease in patients with COVID-19. METHODS AND RESULTS: In this prospective observational clinical trial we examined a cohort of 80 patients with proof of acute respiratory infection and divided them into a COVID-19 cohort (n = 54) and a control cohort (n = 26). KIM-1 and NAG were measured from urine samples collected in the emergency department. We assessed the development of AKI, admission to the intensive care unit (ICU) and intrahospital death as clinical endpoints. Urinary KIM-1 and NAG were not significantly different between patients with SARS-CoV-2 and those with other respiratory infections (each p = n.s.). Eight patients from the COVID-19 cohort and five of the non-COVID-19-patients suffered from acute kidney injury during their stay. Nine COVID-19 patients and two non-COVID-19 patients were admitted to the ICU. KIM-1 was significantly elevated in COVID-19 patients with, compared to those without AKI (p = 0.005), as opposed to NAG and creatinine (each p = n.s.). Furthermore, KIM-1 was significantly elevated in the patients with COVID-19 that had to be transferred to the ICU (p = 0.015), in contrast to NAG and creatinine (each p = n.s.). CONCLUSION: Assessing KIM-1 in patients with COVID-19 might provide additional value in recognizing AKI at an early stage of disease. Further, KIM-1 might indicate higher risk for clinical deterioration as displayed by admission to the ICU.

Urinary N-terminal pro-brain natriuretic peptide: prognostic value in patients with acute chest pain.

AIMS: The objective of this study was to investigate the prognostic value of urinary N-terminal pro-brain natriuretic peptide (NT-proBNP) compared with plasma NT-proBNP in patients presenting with acute chest pain in the emergency department. METHODS AND RESULTS: We measured simultaneously plasma and urinary NT-proBNP at admission in 301 patients with acute chest pain. In our cohort, 174 patients suffered from acute coronary syndrome (ACS). A follow-up (median of 55 months) was performed regarding the endpoints all-cause mortality and major adverse cardiac events (mortality, congestive heart failure, ACS with the necessity of a coronary intervention, and stroke). Fifty-four patients died during follow-up; 98 suffered from the combined endpoint. A significant and positive correlation of urinary and plasma NT-proBNP was found (r = 0.87, P < 0.05). Patients with troponin positive ACS had significantly elevated levels of plasma and urinary NT-proBNP compared with those with unstable angina pectoris or chest wall syndrome (each P < 0.05). The highest levels of both biomarkers were found in patients with congestive heart failure (each P < 0.05). According to Kaplan-Meier analysis, plasma and urinary NT-proBNP were significant predictors for mortality and the combined endpoint in the whole study cohort and in the subgroup of patients with ACS (each P < 0.05). Regarding Cox regression analysis, plasma and urinary NT-proBNP were independent predictors for mortality and the combined endpoint (each P < 0.05). CONCLUSIONS: Urinary NT-proBNP seems to provide a significant predictive value regarding the endpoints all-cause mortality and major adverse cardiac events in patients with acute chest pain and those with ACS.

Decreased GLUT1/NHE1 RNA expression in whole blood predicts disease severity in patients with COVID-19.

AIMS: We aimed to assess whether expression of whole-blood RNA of sodium proton exchanger 1 (NHE1) and glucose transporter 1 (GLUT1) is associated with COVID-19 infection and outcome in patients presenting to the emergency department with respiratory infections. Furthermore, we investigated NHE1 and GLUT1 expression in the myocardium of deceased COVID-19 patients. METHODS AND RESULTS: Whole-blood quantitative assessment of NHE1 and GLUT1 RNA was performed using quantitative PCR in patients with respiratory infection upon first contact in the emergency department and subsequently stratified by SARS-CoV-2 infection status. Assessment of NHE1 and GLUT1 RNA using PCR was also performed in left ventricular myocardium of deceased COVID-19 patients. NHE1 expression is up-regulated in whole blood of patients with COVID-19 compared with other respiratory infections at first medical contact in the emergency department (control: 0.0021 ± 0.0002, COVID-19: 0.0031 ± 0.0003, P = 0.01). The ratio of GLUT1 to NHE1 is significantly decreased in the blood of COVID-19 patients who are subsequently intubated and/or die (severe disease) compared with patients with moderate disease (moderate disease: 0.497 ± 0.083 vs. severe disease: 0.294 ± 0.0336, P = 0.036). This ratio is even further decreased in the myocardium of patients who deceased from COVID-19 in comparison with the myocardium of non-infected donors. CONCLUSIONS: NHE1 and GLUT1 may be critically involved in the disease progression of SARS-CoV-2 infection. We show here that SARS-CoV-2 infection critically disturbs ion channel expression in the heart. A decreased ratio of GLUT1/NHE1 could potentially serve as a biomarker for disease severity in patients with COVID-19.

N-acety-b-D-glucosaminidase: A potential biomarker for early detection of acute kidney injury in acute chest pain.

AIM: Acute kidney injury (AKI) is often underdiagnosed due to several limitations of the renal marker creatinine. Tubular urinary biomarkers may substantially contribute to diagnose AKI early. For early detection of AKI, we evaluated for the first time N-acetyl-ß-d-glucosaminidase (NAG), Kidney-injury-molecule-1 (KIM-1) and neutrophil gelatinase-associated lipocalin (NGAL) in acute chest pain. METHODS: We included 402 chest pain patients aged 18 to 95 years seen in the emergency department. From 311 subjects, blood and urine samples were collected. RESULTS: Thirty-three patients developed an AKI and showed a significant increase in all three tubular markers compared to patients without AKI (each P < .001). According to receiver operating characteristic (ROC) analysis, combining NAG and creatinine showed a significantly increased area under the curve (AUC) compared to creatinine alone (AUC: 0.75 vs 0.87; P < .001). KIM-1, NGAL and cystatin C showed no significant differences in AUC compared to creatinine. In 120 individuals with blood and urine sampling before contrast media exposure, ROC analysis showed a significantly improved diagnostic performance for the combination of both (AUC: 0.83 vs creatinine AUC: 0.66; P = .004). AKI occurrence showed no dependency from CM volume. NAG presented as an independent AKI predictor beside creatinine, age, the diagnosis of myocardial infarction and mean arterial pressure. Regarding the prognostic value for renal replacement therapy, the combination of NAG and creatinine showed a significantly lager AUC than creatinine (AUC: 0.95 vs AUC: 0.85; P < .001). CONCLUSION: NAG presented as a promising marker of impending AKI and the necessity of renal replacement therapy.

The role of the tubular biomarkers NAG, kidney injury molecule-1 and neutrophil gelatinase-associated lipocalin in patients with chest pain before contrast media exposition.

Aim: We evaluated the role of the tubular biomarkers N-acetyl-ß-D-glucosaminidase (NAG), kidney injury molecule-1 (KIM-1) and neutrophil gelatinase-associated lipocalin (NGAL) in patients with chest pain. Methods: Serum and urine samples were collected of 223 patients and 47 healthy controls. None of them was exposed to contrast media. Results: NAG showed among others significant correlation with N-terminal pro brain natriuretic peptide (NTproBNP), troponin I and creatinine. KIM-1 and NGAL showed weaker correlations. NAG was significantly elevated in all subgroups of acute coronary syndrome (ACS) compared with chest wall syndrome and controls. NAG was an independent predictor for the diagnosis of myocardial infarction. Conclusion: NAG may demonstrate the presence of acute tubular injury due to cardiac impairment already in the emergency department. NAG should be evaluated as marker of acute cardiorenal syndrome in patients with chest pain.

Analytical and Clinical Validation of a Point-of-Care Cardiac Troponin T Test with an Improved Detection Limit.

BACKGROUND: The point-of-care test Roche CARDIAC POC Troponin T (PoC TnT) is an improved assay which has been developed for the Roche cobas h 232 system. METHODS: We performed a multicentre evaluation (four sites) to assess the analytical performance of the PoC TnT assay and to compare it with the central laboratory Elecsys® troponin T high sensitive (lab cTnT-hs) assay. RESULTS: The relative mean differences found in method comparisons of PoC TnT vs. lab cTnT-hs ranged from -4.1% to +6.8%. Additionally, there was good concordance between PoC TnT and lab cTnT-hs for the number of samples with troponin T values below the measuring range of 40 ng/L. Lot-to-lot differences of PoC TnT ranged from -8.6% to +4.6%. Within-series coefficients of variation (CV) resulting from 81 ten-fold measurements with patient samples were 9.3%, 11.8%, and 12.9% in the low (40 to < 200 ng/L), medium (200 to < 600 ng/L), and high (600 to 2000 ng/L) measuring range, respectively. Using the system quality control, the mean CV for between-day imprecision was 11.3%. No interference was observed by triglycerides (up to 11.4 mmol/L), bilirubin (up to 376 µmol/L), hemoglobin (up to 0.12 mmol/L), biotin (up to 30 µg/L), rheumatoid factor (up to 200 IU/mL), or with 52 standard or cardiovascular drugs at therapeutic concentrations. There was no influence on the results by varying hematocrit values in a range from 25% to 53%. However, interferences with human anti-mouse antibodies were found. No significant influence on the results was found with PoC TnT by using sample volumes between 135 to 165 µL. High troponin T concentrations up to 500 µg/L did not lead to false low results, indicating no high-concentration hook effect. No cross-reactivity was found between the PoC TnT assay and human skeletal troponin T up to 1000 µg/L (< 0.05%). Diagnostic sensitivity and specificity data of a subpopulation (23 patients) of this study are in agreement with results of another large pre-hospital study. CONCLUSIONS: The PoC TnT assay showed good analytical performance with excellent concordance with the calibration and reference laboratory method. It should therefore be suitable for its intended use in point-of-care settings.

Combined Inhibition of the Renin-Angiotensin System and Neprilysin Positively Influences Complex Mitochondrial Adaptations in Progressive Experimental Heart Failure.

BACKGROUND: Inhibitors of the renin angiotensin system and neprilysin (RAS-/NEP-inhibitors) proved to be extraordinarily beneficial in systolic heart failure. Furthermore, compelling evidence exists that impaired mitochondrial pathways are causatively involved in progressive left ventricular (LV) dysfunction. Consequently, we aimed to assess whether RAS-/NEP-inhibition can attenuate mitochondrial adaptations in experimental heart failure (HF). METHODS AND RESULTS: By progressive right ventricular pacing, distinct HF stages were induced in 15 rabbits, and 6 animals served as controls (CTRL). Six animals with manifest HF (CHF) were treated with the RAS-/NEP-inhibitor omapatrilat. Echocardiographic studies and invasive blood pressure measurements were undertaken during HF progression. Mitochondria were isolated from LV tissue, respectively, and further worked up for proteomic analysis using the SWATH technique. Enzymatic activities of citrate synthase and the electron transfer chain (ETC) complexes I, II, and IV were assessed. Ultrastructural analyses were performed by transmission electron microscopy. During progression to overt HF, intricate expression changes were mainly detected for proteins belonging to the tricarboxylic acid cycle, glucose and fat metabolism, and the ETC complexes, even though ETC complex I, II, or IV enzymatic activities were not significantly influenced. Treatment with a RAS-/NEP-inhibitor then reversed some maladaptive metabolic adaptations, positively influenced the decline of citrate synthase activity, and altered the composition of each respiratory chain complex, even though this was again not accompanied by altered ETC complex enzymatic activities. Finally, ultrastructural evidence pointed to a reduction of autophagolytic and degenerative processes with omapatrilat-treatment. CONCLUSIONS: This study describes complex adaptations of the mitochondrial proteome in experimental tachycardia-induced heart failure and shows that a combined RAS-/NEP-inhibition can beneficially influence mitochondrial key pathways.

Interatrial differences of basal molecular set-up and changes in tachycardia-induced heart failure-a proteomic profiling study.

AIMS: Left and right atria show compelling differences regarding organogenesis and specific clinical diseases. In congestive heart failure (CHF), remodelling of the atria occurs leading to increased arrhythmogenic susceptibility and deterioration of clinical symptoms. We aimed to assess the basal left and right atrial molecular set-up and different chamber-specific atrial changes in heart failure. METHODS AND RESULTS: We combined an animal model of rapid ventricular pacing induced heart failure in the rabbit and a gel-based proteomic screening of left and right atrial specimen. A gene ontology over-representation analysis was performed for biological function. Ultrastructural adaptations were evaluated using transmission electron microscopy. Comparing left and right atria of healthy control animals (CTRL), 39 proteins displayed significant expression differences involving various biological functions. Upon further statistical analyses, four pathways of energy metabolism were confirmed to be significantly over-represented beneath the other biological processes. Rapid ventricular pacing induced severe left ventricular systolic dysfunction, symptomatic heart failure and a macroscopic atrial remodelling. In CHF versus CTRL, metabolic and antioxidative enzymes were differentially expressed and showed chamber-specific bidirectional alterations. Transmission electron microscopy visualized a remarkable and again chamber-specific ultrastructural disturbance of mitochondrial morphology. CONCLUSIONS: Our data indicate a diverging basal left and right atrial molecular set-up in the adult healthy heart. In addition, metabolic and antioxidative enzymes are profoundly and chamber-specifically altered during atrial remodelling in progressive heart failure.

Experimental heart failure induces alterations of the lung proteome--insight into molecular mechanisms.

BACKGROUND: Heart failure (CHF) is characterized by dyspnea and pulmonary changes. The underlying molecular adaptations are unclear, but might provide targets for therapeutic interventions. We therefore conceived a study to determine molecular changes of early pulmonary stress failure in a model of tachycardia-induced heart failure. METHODS: CHF was induced in rabbits by progessive right ventricular pacing (n=6). Invasive blood pressure measurements and echocardiography were repeatedly performed. Untreated animals served as controls (n=6). Pulmonary tissue specimens were subjected to two-dimensional gel electrophoresis, and differentially expressed proteins were identified by mass spectrometry. Selected proteins were validated by Western Blot analysis and localized by immunohistochemical staining. RESULTS: CHF animals were characterized by significantly altered functional, morphological, and hemodynamic parameters. Upon proteomic profiling, a total of 33 proteins was found to be differentially expressed in pulmonary tissue of CHF animals (18 up-regulated, and 15 down-regulated) belonging to 4 functional groups: 1. proteins involved in maintaining cytoarchitectural integrity, 2. plasma proteins indicating impaired alveolar-capillary permeability, 3. proteins with antioxidative properties, and 4. proteins participating in the metabolism of selenium compounds CONCLUSION: Experimental heart failure profoundly alters the pulmonary proteome. Our results supplement the current knowledge of pulmonary stress failure by specifying its molecular fundament.