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BackgroundRisk stratification of COVID-19 patients upon hospital admission is key for their successful treatment and efficient utilization of hospital resources. ObjectiveTo evaluate the risk factors associated with ventilation need and mortality. Design, setting and participantsWe established a retrospective cohort of COVID-19 patients from Mass General Brigham hospitals. Demographic, clinical, and admission laboratory data were obtained from electronic medical records of patients admitted to hospital with laboratory-confirmed COVID-19 before May 19th, 2020. Using patients admitted to Massachusetts General Hospital (MGH, derivation cohort), multivariable logistic regression analyses were used to construct the Ventilation in COVID Estimator (VICE) and Death in COVID Estimator (DICE) risk scores. MeasurementsThe primary outcomes were ventilation status and death. ResultsThe entire cohort included 1042 patients (median age, 64 years; 56.8% male). The derivation and validation cohorts for the risk scores included 578 and 464 patients, respectively. We found seven factors to be independently predictive for ventilation requirement (diabetes mellitus, dyspnea, alanine aminotransferase, troponin, C-reactive protein, neutrophil-lymphocyte ratio, and lactate dehydrogenase), and 10 factors to be predictors of in-hospital mortality (age, sex, diabetes mellitus, chronic statin use, albumin, C-reactive protein, neutrophil-lymphocyte ratio, mean corpuscular volume, platelet count, and procalcitonin). Using these factors, we constructed the VICE and DICE risk scores, which performed with C-statistics of at least 0.8 in our cohorts. Importantly, the chronic use of a statin was associated with protection against death due to COVID-19. The VICE and DICE score calculators have been placed on an interactive website freely available to the public (https://covid-calculator.com/). LimitationsOne potential limitation is the modest sample sizes in both our derivation and validation cohorts. ConclusionThe risk scores developed in this study may help clinicians more appropriately determine which COVID-19 patients will need to be managed with greater intensity.
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Emerging evidence suggests that males are more susceptible to severe infection by the SARS-CoV-2 virus than females. A variety of mechanisms may underlie the observed gender-related disparities including differences in sex hormones. However, the precise mechanisms by which female sex hormones may provide protection against SARS-CoV-2 infectivity remains unknown. Here we report new insights into the molecular basis of the interactions between the SARS-CoV-2 spike (S) protein and the human ACE2 receptor. We further observed that glycosylation of the ACE2 receptor enhances SARS-CoV-2 infectivity. Importantly estrogens can disrupt glycan-glycan interactions and glycan-protein interactions between the human ACE2 and the SARS-CoV2 thereby blocking its entry into cells. In a mouse model, estrogens reduced ACE2 glycosylation and thereby alveolar uptake of the SARS-CoV-2 spike protein. These results shed light on a putative mechanism whereby female sex hormones may provide protection from developing severe infection and could inform the development of future therapies against COVID-19.
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Objective To study in vitro the effects of low-intensity pulsed ultrasound (LIPUS) on the proliferation and differentiation of cultured myoblasts,and to explore the cellular and molecular mechanisms behind any therapeutic effect of LIPUS.Methods Myoblasts were isolated from the skeletal muscles of mice and cultured in vitro.Treatment and control groups of proliferating and differentiating myoblasts were defined.The treatment groups were exposed to LIPUS at 1.5 MHz and a spatial and temporal average intensity of 30 mW/cm2,for 20 min daily,the proliferation group for 6 consecutive days and the differentiation group for 4 consecutive days.The cell proliferation kinetics of the proliferation group were analyzed using flow cytometry.The expression of myogenic regulation factor MyoD and heme oxygenase-1 (HO-1) in the proliferation group,and of myosin heavy chain (MHC) in the differentiation group were examined by immunofluorescent staining.Myoblast fusion indexes were analyzed.Results In the LIPUS treatment groups the proliferating myoblasts had a higher ratio of active cells in the G2 and S phases (19.30％ ±5.14％,37.00％ ±8.72％),compared with the controls (10.33％ ± 1.53％,25.00％ ±4.36％),and the proliferation index increased significantly.The expression of HO-1 was up-regulated,while MyoD staining was unchanged.During the induction of differentiation,the myoblasts of the treatment group fused into smaller myotubes and the myoblast fusion index (18.73％ ± 6.81％) was significantly lower than that of the control group (37.52％ ± 11.23％),while MHC expression did not change markedly.Conclusion LIPUS can promote myoblast proliferation while inhibiting their differentiation,but it does not affect the cells' myogenic properties.HO-1 may be involved in the regulation process.