Assays to quantify fibrinolysis: strengths and limitations. Communication from the International Society on Thrombosis and Haemostasis Scientific and Standardization Committee on fibrinolysis.

Fibrinolysis is a series of enzymatic reactions that degrade insoluble fibrin. Plasminogen activators convert the zymogen plasminogen to the active serine protease plasmin, which cleaves and solubilizes crosslinked fibrin clots into fibrin degradation products. The quantity and quality of fibrinolytic enzymes, their respective inhibitors, and clot structure determine overall fibrinolysis. The quantity of protein can be measured by antigen-based assays, and both quantity and quality can be assessed using functional assays. Furthermore, variations of commonly used assays have been reported, which are tailored to address the role(s) of specific fibrinolytic factors and cellular elements (eg, platelets, neutrophils, and red blood cells). Although the concentration and/or activity of a protein can be quantified, how these individual components contribute to the overall fibrinolysis outcome can be challenging to determine. This difficulty is due to temporal changes within and around the thrombi during the clot breakdown, particularly the fibrin matrix structure, and composition. Furthermore, terms such as "fibrinolytic activity/potential," "plasminogen activation," and "plasmin activity" are often used interchangeably despite having different definitions. The purpose of this review is to 1) summarize the assays measuring fibrinolysis activity and potential, 2) facilitate the interpretation of data generated by these assays, and 3) summarize the strengths and limitations of these assays.

Collagen-Specific HSP47+ Myofibroblasts and CD163+ Macrophages Identify Profibrotic Phenotypes in Deceased Hearts With SARS-CoV-2 Infections.

Background Cardiac fibrosis complicates SARS-CoV-2 infections and has been linked to arrhythmic complications in survivors. Accordingly, we sought evidence of increased HSP47 (heat shock protein 47), a stress-inducible chaperone protein that regulates biosynthesis and secretion of procollagen in heart tissue, with the goal of elucidating molecular mechanisms underlying cardiac fibrosis in subjects with this viral infection. Methods and Results Using human autopsy tissue, immunofluorescence, and immunohistochemistry, we quantified Hsp47+ cells and collagen α 1(l) in hearts from people with SARS-CoV-2 infections. Because macrophages are also linked to inflammation, we measured CD163+ cells in the same tissues. We observed irregular groups of spindle-shaped HSP47+ and CD163+ cells as well as increased collagen α 1(I) deposition, each proximate to one another in "hot spots" of ≈40% of hearts after SARS-CoV-2 infection (HSP47+ P<0.05 versus nonfibrotics and P<0.001 versus controls). Because HSP47+ cells are consistent with myofibroblasts, subjects with hot spots are termed "profibrotic." The remaining 60% of subjects dying with COVID-19 without hot spots are referred to as "nonfibrotic." No control subject exhibited hot spots. Conclusions Colocalization of myofibroblasts, M2(CD163+) macrophages, and collagen α 1(l) may be the first evidence of a COVID-19-related "profibrotic phenotype" in human hearts in situ. The potential public health and diagnostic implications of these observations require follow-up to further define mechanisms of viral-mediated cardiac fibrosis.

The correlations among racial/ethnic groups, hypertriglyceridemia, thrombosis, and mortality in hospitalized patients with COVID-19.

Reports of racial and ethnic disparities regarding both rates of infection of the SARS-CoV-2 virus and morbidity of the coronavirus disease-19 (COVID-19) contain profound differences depending on the population. Our previous study has shown that patients with COVID-19 who developed hypertriglyceridemia during hospitalization have a 2.3 times higher mortality rate. However, whether the correlation between hypertriglyceridemia and mortality has disparity among different racial and ethnic groups is unknown. In this study, we investigated the impact of race/ethnicity on the correlation between hypertriglyceridemia and mortality in hospitalized patients with COVID-19. De-identified information from 904 hospitalized patients diagnosed with COVID-19 between March 2020 and June 2021 were extracted from the Medical College of Wisconsin Clinical Data Warehouse. A multivariable regression analysis suggested that the Asians and non-White Hispanics had 4 or 3.9 times higher mortality rate, respectively, after adjusting for age, morbid obesity (BMI ≥40), and gender. The hypertriglyceridemia (≥150 mg/dL) was associated with higher mortality, after adjusting for age, gender, and morbid obesity. The baseline hypertriglyceridemia occurrence had relevantly more consistent percentages among all racial/ethnic groups. However, non-White Hispanic and Asian patients had the highest frequencies of peak hypertriglyceridemia occurrence during hospitalization. The peak hypertriglyceridemia developed during hospitalization correlates with the incidence of thrombosis after adjusting for morbid obesity, age, and sex. In summary, in this retrospective study of 904 hospitalized COVID-19 patients, Asians and non-White Hispanics had a greater likelihood of developing hypertriglyceridemia during hospitalization and mortality than White patients.

The correlations among racial/ethnic groups, hypertriglyceridemia, thrombosis, and mortality in hospitalized patients with COVID-19

Reports of racial and ethnic disparities regarding both rates of infection of the SARS-CoV-2 virus and morbidity of the coronavirus disease-19 (COVID-19) contain profound differences depending on the population. Our previous study has shown that patients with COVID-19 who developed hypertriglyceridemia during hospitalization have a 2.3 times higher mortality. However, whether the correlation between hypertriglyceridemia and mortality has disparity among different racial and ethnic groups is unknown. In this study, we investigated the impact of race/ethnicity on the correlation between hypertriglyceridemia and mortality in hospitalized patients with COVID-19. De-identified information from 904 hospitalized patients diagnosed with COVID-19 between March 2020 and June 2021 were extracted from the Medical College of Wisconsin Clinical Data Warehouse. A multivariable regression analysis suggested that the Asians and non-White Hispanics had 4 or 3.9 times of higher mortality, respectively, after adjusting for age, morbid obesity (BMI >40), and gender. The hypertriglyceridemia (>150 mg/dL) was associated with higher mortality, after adjusting for age, gender, and morbid obesity. The baseline hypertriglyceridemia occurrence had relevantly more consistent percentages among all racial/ethnic groups. However, non-White Hispanic and Asian patients had the highest frequencies of peak hypertriglyceridemia occurrence during hospitalization. The peak hypertriglyceridemia developed during hospitalization correlates with the incidence of thrombosis after adjusting for morbid obesity, age, and sex. In summary, in this retrospective study of 904 hospitalized COVID-19 patients, Asians and non-White Hispanics had a greater likelihood of developing hypertriglyceridemia during hospitalization and mortality than White patients.

VMP1 and TMEM41B are essential for DMV formation during ß-coronavirus infection.

ß-coronaviruses reshape host cell endomembranes to form double-membrane vesicles (DMVs) for genome replication and transcription. Ectopically expressed viral nonstructural proteins nsp3 and nsp4 interact to zipper and bend the ER for DMV biogenesis. Genome-wide screens revealed the autophagy proteins VMP1 and TMEM41B as important host factors for SARS-CoV-2 infection. Here, we demonstrated that DMV biogenesis, induced by virus infection or expression of nsp3/4, is impaired in the VMP1 KO or TMEM41B KO cells. In VMP1 KO cells, the nsp3/4 complex forms normally, but the zippered ER fails to close into DMVs. In TMEM41B KO cells, the nsp3-nsp4 interaction is reduced and DMV formation is suppressed. Thus, VMP1 and TMEM41B function at different steps during DMV formation. VMP1 was shown to regulate cross-membrane phosphatidylserine (PS) distribution. Inhibiting PS synthesis partially rescues the DMV defects in VMP1 KO cells, suggesting that PS participates in DMV formation. We provide molecular insights into the collaboration of host factors with viral proteins to remodel host organelles.

Impact of COVID-19 on Hematology-Oncology Trainees: A Quantitative and Qualitative Assessment.

PURPOSE: Graduate medical and research training has drastically changed during the COVID-19 pandemic, with widespread implementation of virtual learning, redeployment from core rotations to the care of patients with COVID-19, and significant emotional and physical stressors. The specific experience of hematology-oncology (HO) fellows during the COVID-19 pandemic is not known. METHODS: We conducted a mixed-methods study using a survey of Likert-style and open-ended questions to assess the training experience and well-being of HO fellows, including both clinical and postdoctoral trainee members of the American Society of Hematology and ASCO. RESULTS: A total of 2,306 surveys were distributed by e-mail; 548 (23.8%) fellows completed the survey. Nearly 40% of fellows felt that they had not received adequate mental health support during the pandemic, and 22% reported new symptoms of burnout. Pre-existing burnout before the pandemic, COVID-19-related clinical work, and working in a primary research or nonclinical setting were associated with increased burnout on multivariable logistic regression. Qualitative thematic analysis of open-ended responses revealed significant concerns about employment after training completion, perceived variable quality of virtual education and board preparation, loss of clinical opportunities to prepare for independent clinical practice, inadequate grant funding opportunities in part because of shifting research priorities, variable productivity, and mental health or stress during the pandemic. CONCLUSION: HO fellows have been profoundly affected by the pandemic, and our data illustrate multiple avenues for fellowship programs and national organizations to support both clinical and postdoctoral trainees.

Hypertriglyceridemia during hospitalization independently associates with mortality in patients with COVID-19.

BACKGROUND: Alteration in blood triglyceride levels have been found in patients with coronavirus disease 2019 (COVID-19). However, the association between hypertriglyceridemia and mortality in COVID-19 patients is unknown. OBJECTIVE: To investigate the association between alteration in triglyceride level and mortality in hospitalized COVID-19 patients. METHODS: We conducted a retrospective study of 600 hospitalized patients with COVID-19 diagnosis (ICD10CM:U07.1) and/or SARS-CoV-2 positive testing results between March 1, 2020 and December 21, 2020 at a tertiary academic medical center in Milwaukee, Wisconsin. De-identified data, including demographics, medical history, and blood triglyceride levels were collected and analyzed. Of the 600 patients, 109 patients died. The triglyceride value on admission was considered the baseline and the peak was defined as the highest level reported during the entire period of hospitalization. Hypertriglyceridemia was defined as greater than 150 mg/dl. Logistic regression analyses were performed to evaluate the association between hypertriglyceridemia and mortality. RESULTS: There was no significant difference in baseline triglyceride levels between non-survivors (n = 109) and survivors (n = 491) [Median 127 vs. 113 mg/dl, p = 0.213]. However, the non-survivors had significantly higher peak triglyceride levels during hospitalization [Median 179 vs. 134 mg/dl, p < 0.001]. Importantly, hypertriglyceridemia independently associated with mortality [odds ratio=2.3 (95% CI: 1.4-3.7, p = 0.001)], after adjusting for age, gender, obesity, history of hypertension and diabetes, high CRP, high leukocyte count and glucocorticoid treatment in a multivariable logistic regression model. CONCLUSIONS: Hypertriglyceridemia during hospitalization is independently associated with 2.3 times higher mortality in COVID-19 patients. Prospective studies are needed to independently validate this retrospective analysis.

Hospice care self-efficacy among clinical medical staff working in the coronavirus disease 2019 (COVID-19) isolation wards of designated hospitals: a cross-sectional study.

BACKGROUND: The COVID-19 pandemic has caused more than 462,417 deaths worldwide. A large number of patients with severe COVID-19 face death in hospital. Hospice care is truly a philosophy of care that delivers patient-centred care to the terminally ill and their families. Hospice care could provide many benefits for patients, families, and for hospice caregivers. The aim of this study is to investigate hospice care self-efficacy and identify its predictors among Chinese clinical medical staff in COVID-19 isolation wards of designated hospitals. METHODS: A cross-sectional design was used. The Hospice Care Self-Efficacy, Self-Competence in Death Work Scale, Positive Aspects of Caregiving, and Simplified Coping Style Questionnaires were administered between February and April 2020. A total of 281 eligible medical staff responded to the questionnaires, with a response rate of ≥78.9%. RESULTS: The mean score of hospice care self-efficacy was 47.04 (SD = 7.72). Self-efficacy was predicted by self-competence in death work (B = 0.433, P < 0.001), positive aspects of caregiving (B = 0.149, P = 0.027), positive coping (B = 0.219, P < 0.001), giving hospice care to dying or dead patients before fighting against COVID-19 (B = -1.487, P = 0.023), occupational exposure while fighting against COVID-19 (B = -5.244, P = 0.004), holding respect for life and professional sentiment as motivation in fighting against COVID-19 (B = 2.372, P = 0.031), and grade of hospital employment (B = -1.426, P = 0.024). The variables co-explained 58.7% variation of hospice care self-efficacy. CONCLUSION: Clinical nurses and physicians fighting COVID-19 reported a moderate level of hospice care self-efficacy during this pandemic. Exploring the traditional Chinese philosophy of life to learn from its strengths and make up for its weaknesses and applying it to hospice care may provide a new framework for facing death and dying during the COVID-19 pandemic. Continuous hospice care education to improve self-competence in death work, taking effective measures to mobilize positive psychological resources, and providing safer practice environments to avoid occupational exposure are also essential for the improvement of the hospice care self-efficacy of clinical nurses and physicians. These measures help caregivers deal effectively with death and dying while fighting against the COVID-19 pandemic.

Erratum to hydrogen/oxygen mixed gas inhalation improves disease severity and dyspnea in patients with Coronavirus disease 2019 in a recent multicenter, open-label clinical trial.

[This corrects the article DOI: 10.21037/jtd-2020-057.].