Remdesivir and Mortality in Patients With Coronavirus Disease 2019.

BACKGROUND: The impact of remdesivir (RDV) on mortality rates in coronavirus disease 2019 (COVID-19) is controversial, and the mortality effect in subgroups of baseline disease severity has been incompletely explored. The purpose of this study was to assess the association of RDV with mortality rates in patients with COVID-19. METHODS: In this retrospective cohort study we compared persons receiving RDV with those receiving best supportive care (BSC). Patients hospitalized between 28 February and 28 May 2020 with laboratory-confirmed severe acute respiratory syndrome coronavirus 2 infection were included with the development of COVID-19 pneumonia on chest radiography and hypoxia requiring supplemental oxygen or oxygen saturation ≤94% with room air. The primary outcome was overall survival, assessed with time-dependent Cox proportional hazards regression and multivariable adjustment, including calendar time, baseline patient characteristics, corticosteroid use, and random effects for hospital. RESULTS: A total of 1138 patients were enrolled, including 286 who received RDV and 852 treated with BSC, 400 of whom received hydroxychloroquine. Corticosteroids were used in 20.4% of the cohort (12.6% in RDV and 23% in BSC). Comparing persons receiving RDV with those receiving BSC, the hazard ratio (95% confidence interval) for death was 0.46 (.31-.69) in the univariate model (P < .001) and 0.60 (.40-.90) in the risk-adjusted model (P = .01). In the subgroup of persons with baseline use of low-flow oxygen, the hazard ratio (95% confidence interval) for death in RDV compared with BSC was 0.63 (.39-1.00; P = .049). CONCLUSION: Treatment with RDV was associated with lower mortality rates than BSC. These findings remain the same in the subgroup with baseline use of low-flow oxygen.

Endothelial cell disruption drives increased blood-brain barrier permeability and cerebral edema in the Dahl SS/jr rat model of superimposed preeclampsia.

Preeclampsia is characterized by increases in blood pressure and proteinuria in late pregnancy, and neurological symptoms can appear in the form of headaches, blurred vision, cerebral edema, and, in the most severe cases, seizures (eclampsia). The causes for these cerebral manifestations remain unknown, so the use of animal models that mimic preeclampsia is essential to understanding its pathogenesis. The Dahl salt-sensitive (Dahl SS/jr) rat model develops spontaneous preeclampsia superimposed on chronic hypertension; therefore, we hypothesized that the Dahl SS/jr rat would display cerebrovascular features similar to those seen in human preeclampsia. Furthermore, we predicted that this model would allow for the identification of mechanisms underlying these changes. The pregnant Dahl SS/jr rat displayed increased cerebral edema and blood-brain barrier disruption despite tighter control of cerebral blood flow autoregulation and vascular smooth muscle myogenic tone. Analysis of cerebral endothelial cell morphology revealed increased opening of tight junctions, basement membrane dissolution, and vesicle formation. RNAseq analysis identified that genes related to endothelial cell tight junctions and blood-brain barrier integrity were differentially expressed in cerebral vessels from pregnant Dahl SS/jr compared with healthy pregnant Sprague Dawley rats. Overall, our data reveal new insights into mechanisms involved in the cerebrovascular dysfunction of preeclampsia.NEW & NOTEWORTHY This study uses the Dahl SS/jr rat as a preclinical model of spontaneous superimposed preeclampsia to demonstrate uncoupling of cerebral vascular permeability and blood-brain barrier disruption from cerebral blood flow autoregulatory dysfunction and myogenic tone. Additionally, the data presented in this study lay the foundational framework on which future experiments assessing specific transcellular transport components such as individual transporter protein expression and components of the vesicular transport system (caveolae) can be built to help reveal a potential direct mechanistic insight into the causes of cerebrovascular complications during preeclamptic pregnancies.

Hypertension and endothelial dysfunction in the pristane model of systemic lupus erythematosus.

Autoimmune diseases such as psoriasis, rheumatoid arthritis, and systemic lupus erythematosus (SLE) have high rates of hypertension and cardiovascular disease. Systemic lupus erythematosus is a prototypic autoimmune disorder that primarily affects women of childbearing age and is associated with a loss of self-tolerance, autoreactive B and T lymphocytes, and the production of autoantibodies, especially to nuclear components. In this study, we hypothesized that the pristane-inducible model of SLE would develop hypertension and vascular dysfunction as the disease progressed. To test this hypothesis, female C57BL/6 mice were administered PBS or pristane. Seven months after pristane administration, mice developed various autoantibodies, including anti-dsDNA IgG, anti-ssDNA IgG, and anti-nRNP IgG, as well as hypergammaglobulinemia. Several other immunological changes, including increased circulating neutrophils and increased CD4- CD8- (double negative) thymocytes were also detected. Mean arterial pressure (MAP) was elevated in pristane-treated mice when compared to PBS-treated mice. In addition, second-order mesenteric arteries from pristine-treated mice had impaired relaxation to the endothelium-dependent vasodilator acetylcholine compared to PBS-treated mice. These data suggest that the immune system dysfunction present in the pristane model of lupus contributes to the development of hypertension and vascular dysfunction.

Introduction of Procalcitonin Testing and Antibiotic Utilization for Acute Exacerbations of Chronic Obstructive Pulmonary Disease.

BACKGROUND: The majority of acute exacerbations of chronic obstructive pulmonary disease (AECOPD) are triggered by nonbacterial causes, yet most patients receive antibiotics. Treatment guided by procalcitonin (PCT), a sensitive biomarker of bacterial infection, safely decreases antibiotic use in many controlled trials. We evaluated PCT implementation for inpatients with AECOPD at a large academic hospital. METHODS: All patients admitted for AECOPD during the first 6 months of PCT-guided therapy were eligible for inclusion in this retrospective cohort study. Patients with PCT performed were compared with those without PCT. The primary outcome was antibiotic days of therapy (DOT). Secondary outcomes included 30-day readmission and mortality. RESULTS: Of the 238 AECOPD admissions, 73 (31%) had PCT performed. Procalcitonin-tested patients were more likely to meet systemic inflammatory response syndrome (SIRS) criteria, require intensive care unit (ICU)-level care, and have a longer length of stay (LOS) compared with those without PCT. Even after adjustment for these factors, PCT-tested patients received more inpatient DOT and there was no difference in total DOT. However, a low PCT value (<0.25 ng/mL) was associated with a 25.5% (P ⩽ .001) decrease in intravenous (IV) antibiotic DOT. Guideline-recommended follow-up testing was rare (12%). Procalcitonin measurement had no effect on 30-day readmission or mortality. CONCLUSIONS: In this real-world analysis of inpatients with AECOPD, PCT-guided therapy was poorly adopted by providers and was not associated with a decrease in total antibiotic DOT. However, a low PCT level was associated with a 25.5% decrease in IV antibiotic DOT, suggesting increased comfort stepping down from IV to PO therapy.

Oxygen deprivation influences the survival of Listeria monocytogenes in gerbils.

Listeria monocytogenes is a facultative anaerobic foodborne pathogen capable of surviving harsh environments. Recent work has indicated that anaerobic conditions increase the resistance capability of certain strains to environmental stressors. The goal of the study was to conduct a preliminary study to determine whether exposure to anaerobic conditions prior to infection increases the ability to survive in vivo. Gerbils were inoculated with one of five doses of the L. monocytogenes strain F2365 by oral gavage: phosphate-buffered saline (control), 5 × 106 colony forming units aerobic culture (low aerobic), 5 × 108 aerobic culture (high aerobic), 5 × 106 anaerobic culture (low anaerobic), or 5 × 108 anaerobic culture (high anaerobic) dose of F2365. Gerbils inoculated with a high aerobic or anaerobic dose exhibited significant weight loss. Gerbils administered either the low or high anaerobic dose had at least 3 log10 of L. monocytogenes present in fecal samples, which contrasted with gerbils that received the low aerobic dose. Animals that received the high anaerobic dose had a significant increase in bacterial loads within the liver. Histologic examination of the L. monocytogenes positive livers exhibited locally extensive areas of hepatocellular necrosis, though the extent of this damage differed between treatment groups. Microbial community analysis of the cecum from gerbils infected with L. monocytogenes indicated that the abundance of Bacteroidales and Clostridiales increased and there was a decrease in the abundance of Spirochaetales. This study suggests that anaerobic conditions alter the localization pattern of L. monocytogenes within the gastrointestinal tract. These findings could relate to how different populations are more susceptible to listeriosis, as oxygen availability may differ within the gastrointestinal tract.

Influence of pH on bile sensitivity amongst various strains of Listeria monocytogenes under aerobic and anaerobic conditions.

Listeria monocytogenes is a dangerous bacterium that causes the food-borne disease listeriosis and accounts for nearly 20% of food-borne deaths. This organism can survive the body's natural defences within the digestive tract, including acidic conditions and bile. Although the bile response has been analysed, limited information is available concerning the ability of L. monocytogenes to resist bile under anaerobic conditions, especially at acidic pH, which mimics conditions within the duodenum. Additionally, it is not known how the bile response varies between serotypes. In this study, the survival of strains representing six serotypes was analysed under aerobic and anaerobic conditions following exposure to bile. Exposure to bile salts at acidic pH increased toxicity of bile, resulting in a significant reduction in survival for all strains tested. However, following this initial reduction, no significant reduction was observed for an additional 2 h except for strain 10403S (P = 0.002). Anaerobic cultivation increased bile resistance, but a significant increase was only observed in virulent strains when exposed to bile at pH 5.5. Exposure to pH 3.0 prior to bile decreased viability amongst avirulent strains in bile in acidic conditions; oxygen availability did not influence viability. Together, the data suggested that being able to sense and respond to oxygen availability may influence the expression of stress response mechanisms, and this response may correspond to disease outcome. Further research is needed on additional strains to determine how L. monocytogenes senses and responds to oxygen and how this varies between invasive and non-invasive strains.