BACKGROUND In 2013, New York began requiring hospitals to follow protocols for the early identification and treatment of sepsis. However, there is controversy about whether more rapid treatment of sepsis improves outcomes in patients. METHODS We studied data from patients with sepsis and septic shock that were reported to the New York State Department of Health from April 1, 2014, to June 30, 2016. Patients had a sepsis protocol initiated within 6 hours after arrival in the emergency department and had all items in a 3‐hour bundle of care for patients with sepsis (i.e., blood cultures, broad‐spectrum antibiotic agents, and lactate measurement) completed within 12 hours. Multilevel models were used to assess the associations between the time until completion of the 3‐hour bundle and risk‐adjusted mortality. We also examined the times to the administration of antibiotics and to the completion of an initial bolus of intravenous fluid. RESULTS Among 49,331 patients at 149 hospitals, 40,696 (82.5%) had the 3‐hour bundle completed within 3 hours. The median time to completion of the 3‐hour bundle was 1.30 hours (interquartile range, 0.65 to 2.35), the median time to the administration of antibiotics was 0.95 hours (interquartile range, 0.35 to 1.95), and the median time to completion of the fluid bolus was 2.56 hours (interquartile range, 1.33 to 4.20). Among patients who had the 3‐hour bundle completed within 12 hours, a longer time to the completion of the bundle was associated with higher risk‐adjusted in‐hospital mortality (odds ratio, 1.04 per hour; 95% confidence interval [CI], 1.02 to 1.05; P<0.001), as was a longer time to the administration of antibiotics (odds ratio, 1.04 per hour; 95% CI, 1.03 to 1.06; P<0.001) but not a longer time to the completion of a bolus of intravenous fluids (odds ratio, 1.01 per hour; 95% CI, 0.99 to 1.02; P=0.21). CONCLUSIONS More rapid completion of a 3‐hour bundle of sepsis care and rapid administration of antibiotics, but not rapid completion of an initial bolus of intravenous fluids, were associated with lower risk‐adjusted in‐hospital mortality. (Funded by the National Institutes of Health and others.)

Supplement to: Time to treatment and mortality during mandated emergency care for sepsis.

Plasma levels of high-density lipoprotein (HDL) inversely correlate with the incidence of cardiovascular diseases (CVD). The causal relationship between plasma HDL-cholesterol levels and CVD has been called into question by Mendelian randomization studies and the majority of clinical trials not showing any benefit of plasma HDL-cholesterol raising drugs on CVD. Nonetheless, recent Mendelian randomization studies including an increased number of CVD cases compared to earlier studies have confirmed that HDL-cholesterol levels and CVD are causally linked. Moreover, several studies in large population cohorts have shown that the cholesterol efflux capacity of HDL inversely correlates with CVD. Cholesterol efflux pathways exert anti-inflammatory and anti-atherogenic effects by suppressing proliferation of hematopoietic stem and progenitor cells, and inflammation and inflammasome activation in macrophages. Cholesterol efflux pathways also suppress the accumulation of cholesteryl esters in macrophages, i.e. macrophage foam cell formation. Recent single-cell RNASeq studies on atherosclerotic plaques have suggested that macrophage foam cells have lower expression of inflammatory genes than non-foam cells, probably reflecting liver X receptor activation, upregulation of ATP Binding Cassette A1 and G1 cholesterol transporters and suppression of inflammation. However, when these pathways are defective lesional foam cells may become pro-inflammatory.

Cholesterol efflux pathways, inflammation, and atherosclerosis.

The vascular endothelium serves as a barrier between the intravascular and extravascular compartments. High-density lipoproteins (HDL) have two kinds of interactions with this barrier. First, bloodborne HDL must pass the endothelium to access extravascular tissues, for example the arterial wall or the brain, to mediate cholesterol efflux from macrophages and other cells or exert other functions. To complete reverse cholesterol transport, HDL must even pass the endothelium a second time to re-enter circulation via the lymphatics. Transendothelial HDL transport is a regulated process involving scavenger receptor SR-BI, endothelial lipase, and ATP binding cassette transporters A1 and G1. Second, HDL helps to maintain the integrity of the endothelial barrier by (i) promoting junction closure as well as (ii) repair by stimulating the proliferation and migration of endothelial cells and their progenitor cells, and by preventing (iii) loss of glycocalix, (iv) apoptosis, as well as (v) transmigration of inflammatory cells. Additional vasoprotective functions of HDL include (vi) the induction of nitric oxide (NO) production and (vii) the inhibition of reactive oxygen species (ROS) production. These vasoprotective functions are exerted by the interactions of HDL particles with SR-BI as well as specific agonists carried by HDL, notably sphingosine-1-phophate (S1P), with their specific cellular counterparts, e.g., S1P receptors. Various diseases modify the protein and lipid composition and thereby the endothelial functionality of HDL. Thorough understanding of the structure-function relationships underlying the multiple interactions of HDL with endothelial cells is expected to elucidate new targets and strategies for the treatment or prevention of various diseases.

https://www.zora.uzh.ch/id/eprint/205857/1/cells-10-01041.pdf

The Endothelium Is Both a Target and a Barrier of HDL's Protective Functions.

BACKGROUND: SARS-CoV-2 is a rapidly spreading coronavirus responsible for the Covid-19 pandemic, which is characterized by severe respiratory infection. Many factors have been identified as risk factors for SARS-CoV-2, with much early attention being paid to body mass index (BMI), which is a well-known cardiometabolic risk factor. OBJECTIVE: This study seeks to examine the impact of additional baseline cardiometabolic risk factors including high density lipoprotein-cholesterol (HDL-C), low density lipoprotein-cholesterol (LDL-C), Apolipoprotein A-I (ApoA-I), Apolipoprotein B (ApoB), triglycerides, hemoglobin A1c (HbA1c) and diabetes on the odds of testing positive for SARS-CoV-2 in UK Biobank (UKB) study participants. METHODS: We examined the effect of BMI, lipid profiles, diabetes and alcohol intake on the odds of testing positive for SARS-Cov-2 among 9,005 UKB participants tested for SARS-CoV-2 from March 16 through July 14, 2020. Odds ratios and 95% confidence intervals were computed using logistic regression adjusted for age, sex and ancestry. RESULTS: Higher BMI, Type II diabetes and HbA1c were associated with increased SARS-CoV-2 odds (p < 0.05) while HDL-C and ApoA-I were associated with decreased odds (p < 0.001). Though the effect of BMI, Type II diabetes and HbA1c were eliminated when HDL-C was controlled, the effect of HDL-C remained significant when BMI was controlled for. LDL-C, ApoB and triglyceride levels were not found to be significantly associated with increased odds. CONCLUSION: Elevated HDL-C and ApoA-I levels were associated with reduced odds of testing positive for SARS-CoV-2, while higher BMI, type II diabetes and HbA1c were associated with increased odds. The effects of BMI, type II diabetes and HbA1c levels were no longer significant after controlling for HDL-C, suggesting that these effects may be mediated in part through regulation of HDL-C levels. In summary, our study suggests that baseline HDL-C level may be useful for stratifying SARS-CoV-2 infection risk and corroborates the emerging picture that HDL-C may confer protection against sepsis in general and SARS-CoV-2 in particular.

/pdf/baseline-cardiometabolic-profiles-and-sars-cov-2-infection-4l1nlu8h2j.pdf

Baseline cardiometabolic profiles and SARS-CoV-2 infection in the UK Biobank.

The transmissible respiratory disease COVID-19, caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has affected millions of people worldwide since its first reported outbreak in December of 2019 in Wuhan, China. Since then, multiple studies have shown an inverse correlation between the levels of high-density lipoprotein (HDL) particles and the severity of COVID-19, with low HDL levels being associated with an increased risk of severe outcomes. Some studies revealed that HDL binds to SARS-CoV-2 particles via the virus's spike protein and, under certain conditions, such as low HDL particle concentrations, it facilitates SARS-CoV-2 binding to angiotensin-converting enzyme 2 (ACE2) and infection of host cells. Other studies, however, reported that HDL suppressed SARS-CoV-2 infection. In both cases, the ability of HDL to enhance or suppress virus infection appears to be dependent on the expression of the HDL receptor, namely, the Scavenger Receptor Class B type 1 (SR-B1), in the target cells. SR-B1 and HDL represent crucial mediators of cholesterol metabolism. Herein, we review the complex role of HDL and SR-B1 in SARS-CoV-2-induced disease. We also review recent advances in our understanding of HDL structure, properties, and function during SARS-CoV-2 infection and the resulting COVID-19 disease.

Good Cholesterol Gone Bad? HDL and COVID-19.

Background: The high-density lipoprotein hypothesis of atherosclerosis has been challenged by clinical trials of cholesteryl ester transfer protein (CETP) inhibitors, which failed to show significa...

Lubos Bohunek

Papers

Inhibition of Cholesteryl Ester Transfer Protein Preserves High-Density Lipoprotein Cholesterol and Improves Survival in Sepsis.