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Multiple randomized controlled trials (RCTs) have assessed the effects of supplementation with eicosapentaenoic acid plus docosahexaenoic acid (omega-3 polyunsaturated fatty acids, commonly called fish oils) on the occurrence of clinical cardiovascular diseases. Although the effects of supplementation for the primary prevention of clinical cardiovascular events in the general population have not been examined, RCTs have assessed the role of supplementation in secondary prevention among patients with diabetes mellitus and prediabetes, patients at high risk of cardiovascular disease, and those with prevalent coronary heart disease. In this scientific advisory, we take a clinical approach and focus on common indications for omega-3 polyunsaturated fatty acid supplements related to the prevention of clinical cardiovascular events. We limited the scope of our review to large RCTs of supplementation with major clinical cardiovascular disease end points; meta-analyses were considered secondarily. We discuss the features of available RCTs and provide the rationale for our recommendations. We then use existing American Heart Association criteria to assess the strength of the recommendation and the level of evidence. On the basis of our review of the cumulative evidence from RCTs designed to assess the effect of omega-3 polyunsaturated fatty acid supplementation on clinical cardiovascular events, we update prior recommendations for patients with prevalent coronary heart disease, and we offer recommendations, when data are available, for patients with other clinical indications, including patients with diabetes mellitus and prediabetes and those with high risk of cardiovascular disease, stroke, heart failure, and atrial fibrillation.

In chow-fed mice, ASO-mediated depletion of CGI-58 did not alter weight gain, plasma TG, or plasma glucose, yet raised hepatic TG levels ‫ف‬ 4-fold. When challenged with a high-fat diet (HFD), CGI-58 ASO-treated mice were protected against diet-induced obesity, but their hepatic contents of TG, diacylglycerols, and ceramides were all elevated, and intriguingly, their hepatic phosphatidylglycerol content was increased by 10-fold. These hepatic lipid alterations were associated with signifi cant decreases in hepatic TG hydrolase activity, hepatic lipoprotein-TG secretion, and plasma concentrations of ketones, nonesterifi ed fatty acids, and insulin. Additionally, HFD-fed CGI-58 ASO-treated mice were more glucose tolerant and insulin sensitive.

Background-Stearoyl-coenzyme A desaturase 1 (SCD1) is a well-known enhancer of the metabolic syndrome. The purpose of the present study was to investigate the role of SCD1 in lipoprotein metabolism and atherosclerosis progression. Methods and Results-Antisense oligonucleotides were used to inhibit SCD1 in a mouse model of hyperlipidemia and atherosclerosis (LDLr Ϫ/Ϫ Apob 100/100 ). In agreement with previous reports, inhibition of SCD1 protected against diet-induced obesity, insulin resistance, and hepatic steatosis. Unexpectedly, however, SCD1 inhibition strongly promoted aortic atherosclerosis, which could not be reversed by dietary oleate. Further analyses revealed that SCD1 inhibition promoted accumulation of saturated fatty acids in plasma and tissues and reduced plasma triglyceride, yet had little impact on low-density lipoprotein cholesterol. Because dietary saturated fatty acids have been shown to promote inflammation through toll-like receptor 4, we examined macrophage toll-like receptor 4 function. Interestingly, SCD1 inhibition resulted in alterations in macrophage membrane lipid composition and marked hypersensitivity to toll-like receptor 4 agonists. Conclusions-This study demonstrates that atherosclerosis can occur independently of obesity and insulin resistance and argues against SCD1 inhibition as a safe therapeutic target for the metabolic syndrome.

Deletion of acyl-CoA:cholesterol O-acyltransferase 2 (ACAT2) in mice results in resistance to diet-induced hypercholesterolemia and protection against atherosclerosis. Recently, our group has shown that liver-specific inhibition of ACAT2 via antisense oligonucleotide (ASO)-mediated targeting likewise limits atherosclerosis. However, whether this atheroprotective effect was mediated by: 1) prevention of packaging of cholesterol into apoB-containing lipoproteins, 2) augmentation of nascent HDL cholesterol secretion, or 3) increased hepatobiliary sterol secretion was not examined. Therefore, the purpose of these studies was to determine whether hepatic ACAT2 is rate-limiting in all three of these important routes of cholesterol homeostasis. Liver-specific depletion of ACAT2 resulted in reduced packaging of cholesterol into apoB-containing lipoproteins (very low density lipoprotein, intermediate density lipoprotein, and low density lipoprotein), whereas high density lipoprotein cholesterol levels remained unchanged. In the liver of ACAT2 ASO-treated mice, cholesterol ester accumulation was dramatically reduced, yet there was no reciprocal accumulation of unesterified cholesterol. Paradoxically, ASO-mediated depletion of hepatic ACAT2 promoted fecal neutral sterol excretion without altering biliary sterol secretion. Interestingly, during isolated liver perfusion, ACAT2 ASO-treated livers had augmented secretion rates of unesterified cholesterol and phospholipid. Furthermore, we demonstrate that liver-derived cholesterol from ACAT2 ASOtreated mice is preferentially delivered to the proximal small intestine as a precursor to fecal excretion. Collectively, these studies provide the first insight into the hepatic itinerary of cholesterol when cholesterol esterification is inhibited only in the liver, and provide evidence for a novel non-biliary route of fecal sterol loss.

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Key Points Question What factors are associated with observed trends in the in-hospital mortality rates in the United States during the first 9 months of the COVID-19 pandemic? Findings In this cohort study of 20 736 patients, in-hospital mortality rates decreased in the US between March and November 2020, even after accounting for the changing mix in patient age, sex, comorbidities, and disease severity at the time of admission. Hospital and intensive care unit length of stay and use of mechanical ventilation decreased over time, whereas the use of glucocorticoids and remdesivir increased. Meaning Changes in age, sex, comorbidities, and disease severity among patients with COVID-19 do not fully explain the decrease in the in-hospital mortality rates observed during the first 9 months of the COVID-19 pandemic.