A time-resolved proteomic and prognostic map of COVID-19

COVID-19 is highly variable in its clinical presentation, ranging from asymptomatic infection to severe organ damage and death. We characterized the time-dependent progression of the disease in 139 COVID-19 inpatients by measuring 86 accredited diagnostic parameters, such as blood cell counts and enzyme activities, as well as untargeted plasma proteomes at 687 sampling points. We report an initial spike in a systemic inflammatory response, which is gradually alleviated and followed by a protein signature indicative of tissue repair, metabolic reconstitution, and immunomodulation. We identify prognostic marker signatures for devising risk-adapted treatment strategies and use machine learning to classify therapeutic needs. We show that the machine learning models based on the proteome are transferable to an independent cohort. Our study presents a map linking routinely used clinical diagnostic parameters to plasma proteomes and their dynamics in an infectious disease

Clinical and virological characteristics of hospitalised COVID-19 patients in a German tertiary care centre during the first wave of the SARS-CoV-2 pandemic: a prospective observational study

Purpose: Adequate patient allocation is pivotal for optimal resource management in strained healthcare systems, and requires detailed knowledge of clinical and virological disease trajectories. The purpose of this work was to identify risk factors associated with need for invasive mechanical ventilation (IMV), to analyse viral kinetics in patients with and without IMV and to provide a comprehensive description of clinical course. Methods: A cohort of 168 hospitalised adult COVID-19 patients enrolled in a prospective observational study at a large European tertiary care centre was analysed. Results: Forty-four per cent (71/161) of patients required invasive mechanical ventilation (IMV). Shorter duration of symptoms before admission (aOR 1.22 per day less, 95% CI 1.10-1.37, p < 0.01) and history of hypertension (aOR 5.55, 95% CI 2.00-16.82, p < 0.01) were associated with need for IMV. Patients on IMV had higher maximal concentrations, slower decline rates, and longer shedding of SARS-CoV-2 than non-IMV patients (33 days, IQR 26-46.75, vs 18 days, IQR 16-46.75, respectively, p < 0.01). Median duration of hospitalisation was 9 days (IQR 6-15.5) for non-IMV and 49.5 days (IQR 36.8-82.5) for IMV patients. Conclusions: Our results indicate a short duration of symptoms before admission as a risk factor for severe disease that merits further investigation and different viral load kinetics in severely affected patients. Median duration of hospitalisation of IMV patients was longer than described for acute respiratory distress syndrome unrelated to COVID-19

Highly Specific Detection of Myostatin Prodomain by an Immunoradiometric Sandwich Assay in Serum of Healthy Individuals and Patients

<div><p>Background</p><p>Myostatin is a muscle derived factor that functions as a negative regulator of skeletal muscle growth. Induction of myostatin expression was observed in rodent models of muscle wasting and in cachectic patients with cancer or pulmonary disease. Therefore, there is an increasing interest to use serum myostatin as a biomarker.</p> <p>Methods</p><p>We established an immunoradiometric sandwich assay (IRMA), which uses a commercially available chicken polyclonal, affinity purified antibody directed against human myostatin prodomain. We determined the serum concentrations of myostatin prodomain in 249 healthy individuals as well as 169 patients with heart failure, 53 patients with cancer and 44 patients with chronic pulmonary disease.</p> <p>Results</p><p>The IRMA had a detection limit of 0.7ng/ml, an intraassay imprecision of ≤14.1% and an interassay imprecision of ≤ 18.9%. The specificity of our assay was demonstrated by size exclusion chromatography, detection of myostatin by Western-blotting and a SMAD-dependent transcriptional-reporter assay in the signal-rich serum fractions, as well as lack of interference by unspecific substances like albumin, hemoglobin or lipids. Myostatin prodomain was stable at room temperature and resistant to freeze-thaw cycles. Apparently healthy individuals over the age of 55 had a median myostatin prodomain serum concentration of 3.9ng/ml (25^th-75^th percentiles, 2-7ng/ml) and we could not detect increased levels in patients with stable chronic heart failure or cancer related weight loss. In contrast, we found strongly elevated concentrations of myostatin prodomain (median 26.9ng/ml, 25^th-75^th percentiles, 7-100ng/ml) in the serum of underweight patients with chronic pulmonary disease.</p> <p>Conclusions</p><p>We established a highly specific IRMA for the quantification of myostatin prodomain concentration in human serum. Our assay could be useful to study myostatin as a biomarker for example in patients with chronic pulmonary disease, as we detected highly elevated myostatin prodomain serum levels in underweight individuals of this group.</p> </div

Myostatin prodomain serum levels in patients compared to healthy individuals.

<p>Myostatin prodomain serum concentrations of apparently healthy individuals <55 (n=63) or ≥55 years of age (n=186), in patients suffering from heart failure (CHF, n=169), gastrointestinal or hepatic cancer (GI-Ca, n=53) and chronic pulmonary disease (CPD, n=44). Data are presented as box (25^th percentile, median, and 75^th percentile) and whisker (10^th and 90^th percentiles) plots.</p

Mean calibration curve of the myostatin prodomain immunoradiometric sandwich assay.

<p>The mean calibration curve of 20 independent assay runs is shown. The x-axis is displayed as logarithmic scale. The values on the y-axis are presented as mean with the 95% confidence limits.</p

Myostatin prodomain serum levels in healthy individuals.

<p><b>A</b> Myostatin prodomain serum concentrations in apparently healthy individuals ≤25 (n=33), 26-55 (n=46), 56-65 (n=138) and ≥66 (n=32) years of age. <b>B</b> Myostatin prodomain serum concentration in apparently healthy male and female individuals ≥55 years of age. Data are presented as box (25^th percentile, median, and 75^th percentile) and whisker (10^th and 90^th percentiles) plots.</p

Specificity of the myostatin prodomain immunoradiometric sandwich assay.

<p><b>A</b> Size-exclusion chromatography of two serum samples analyzed for myostatin prodomain. The dotted line represents the serum with high myostatin prodomain concentration (1629ng/ml), while the continuous line represents the serum with the low myostatin prodomain concentration (1.37ng/ml). B SMAD (CAGA) luciferase reporter assay showing acid induced myostatin activity in different serum fractions of one serum with high and one with low myostatin concentration as determined by our IRMA C Western-blot showing myostatin prodomain levels (arrow, 25kDa) as detected by the propeptide (=prodomain) specific antibody MAB-7881 (R&D systems). Low/high myostatin denotes serum with low and high myostatin prodomain concentrations. D Western-blot showing myostatin ligand dimers (arrow, 25kDa) as detected by the myostatin ligand specific antibody AB3239 (Millipore). + denotes positive control (recombinant myostatin ligand, R&D systems), the arrow head marks the localization of monomeric myostatin ligand (12.5 kDa). Low/high myostatin denotes serum with low and high myostatin prodomain concentrations.</p

Novel Adult-Onset Systolic Cardiomyopathy Due to MYH7 E848G Mutation in Patient-Derived Induced Pluripotent Stem Cells

Summary: A novel myosin heavy chain 7 mutation (E848G) identified in a familial cardiomyopathy was studied in patient-specific induced pluripotent stem cell–derived cardiomyocytes. The cardiomyopathic human induced pluripotent stem cell–derived cardiomyocytes exhibited reduced contractile function as single cells and engineered heart tissues, and genome-edited isogenic cells confirmed the pathogenic nature of the E848G mutation. Reduced contractility may result from impaired interaction between myosin heavy chain 7 and cardiac myosin binding protein C. Key Words: disease-modeling, engineered heart tissue, genetic cardiomyopathy, induced pluripotent stem cell