👤 Liam R Brunham

Most patients with heterozygous familial hypercholesterolemia fail to achieve adequate low-density lipoprotein (LDL) cholesterol lowering. Here we carried out a randomized trial to test the safety and efficacy of obicetrapib, a highly selective cholesteryl ester transfer protein inhibitor that lowers LDL cholesterol levels in patients with heterozygous familial hypercholesterolemia and an LDL cholesterol level ≥70 mg dl Show less

Lipoprotein(a) [Lp(a)] is a genetically determined and independent risk factor for atherosclerotic cardiovascular disease, including acute coronary syndrome, peripheral arterial disease, and stroke, as well as calcific aortic stenosis. Despite its high prevalence, affecting an estimated 20% of Canadians, Lp(a) remains under-recognized and undermeasured in clinical practice. This report provides guidance on the assessment and management of Lp(a) in primary and secondary prevention in the Canadian context. It outlines when and how to measure Lp(a), with a recommendation for universal, one-time testing in adulthood. The report summarizes the pathophysiologic role of Lp(a) in promoting atherosclerosis, thrombosis, and aortic stenosis, and highlights significant ethnic variability in Lp(a) levels and associated risk. It also addresses the limitations of existing cardiovascular risk calculators that omit Lp(a) and discusses the potential role of emerging imaging and treatment strategies, including novel Lp(a)-lowering therapies. Special attention is given to clinical interpretation of Lp(a) values, the role of cascade screening in families, and recommendations for preventive interventions, with an emphasis on current approaches for managing patients with elevated Lp(a) level while awaiting the availability of targeted therapies. The goal of this report is to support clinicians in identifying at-risk individuals earlier and guiding appropriate risk reduction strategies in primary and secondary prevention settings. Show less

Sepsis is the dysregulated immune response to an infection and is a leading cause of mortality. Low levels of high-density lipoprotein (HDL) cholesterol are associated with increased risk of death from sepsis, and increasing levels of HDL by inhibition of cholesteryl ester transfer protein (CETP) has been shown to decrease mortality in mouse models of sepsis. The objective of this study was to investigate the cellular mechanisms by which CETP inhibition and HDL lead to improved survival during sepsis. We found that HDL inhibits lipopolysaccharide (LPS)-induced activation of IL-1β in a mouse model of sepsis. The activation of IL-1β was dependent on the activity of scavenger receptor class B type 1 (SR-B1), and knockdown of SR-B1 significantly attenuated LPS-induced production of IL-1β in macrophages. Additionally, we found that LPS-induced SR-B1 internalization occurs through the endosome-lysosome pathway, which is also likely responsible for LPS degradation in the macrophages. Furthermore, we revealed that raising HDL by CETP inhibition markedly enhanced HDL-mediated anti-inflammatory effects in response to LPS stimulation, and these effects were not due to CETP itself but rather were HDL-dependent. Finally, we show that pharmacological inhibition of CETP significantly improved endotoxemia-induced mortality by inhibiting IL-1β production in the liver and circulation after LPS injection. Pathologically, CETP inhibition attenuated LPS-induced diffuse alveolar damage and hepatocyte necrosis, which may contribute to the improved mortality in mice treated with the CETP inhibitor anacetrapib. Taken together, our findings uncover a cellular mechanism by which HDL attenuates LPS-induced pro-inflammatory response via SR-B1-mediated LPS degradation. Show less

Obicetrapib, a novel, selective cholesteryl ester transfer protein (CETP) inhibitor, reduces low-density lipoprotein cholesterol (LDL-C), LDL particles, apolipoprotein (Apo) B, and lipoprotein(a) [Lp(a)] and increases high-density lipoprotein cholesterol (HDL-C) when added to statins with or without ezetimibe. By substantially reducing LDL-C, obicetrapib has the potential to lower atherogenic lipoproteins in patients with atherosclerotic cardiovascular disease (ASCVD) or heterozygous familial hypercholesterolemia (HeFH) whose LDL-C levels remain high despite treatment with available maximally tolerated lipid-modifying therapies, addressing an unmet medical need in a patient population at high risk for cardiovascular events. BROADWAY (NCT05142722) and BROOKLYN (NCT05425745) are ongoing placebo-controlled, double-blind, randomized Phase III trials designed to examine the efficacy, safety, and tolerability of obicetrapib as an adjunct to dietary intervention and maximally tolerated lipid-modifying therapies in participants with a history of ASCVD and/or underlying HeFH whose LDL-C is not adequately controlled. The primary efficacy endpoint was the percent change in LDL-C from baseline to day 84. Other endpoints included changes in Apo B, non-HDL-C, HDL-C, Apo A1, Lp(a), and triglycerides in addition to parameters evaluating safety, tolerability, and pharmacokinetics. BROADWAY also included an adjudicated assessment of major adverse cardiovascular events, measurements of glucose homeostasis, and an ambulatory blood pressure monitoring substudy. A total of 2,532 participants were randomized in BROADWAY and 354 in BROOKLYN to receive obicetrapib 10 mg or placebo (2:1) for 365 days with follow-up through 35 days after the last dose. Results from both trials are anticipated in 2024. These trials will provide safety and efficacy data to support the potential use of obicetrapib among patients with ASCVD or HeFH with elevated LDL-C for whom existing therapies are not sufficiently effective or well-tolerated. Show less

Sepsis is a leading cause of mortality worldwide, and pneumonia is the most common cause of sepsis in humans. Low levels of high-density lipoprotein cholesterol (HDL-C) levels are associated with an increased risk of death from sepsis, and increasing levels of HDL-C by inhibition of cholesteryl ester transfer protein (CETP) decreases mortality from intraabdominal polymicrobial sepsis in APOE*3-Leiden.CETP mice. Here, we show that treatment with the CETP inhibitor (CETPi) anacetrapib reduced mortality from Streptococcus pneumoniae-induced sepsis in APOE*3-Leiden.CETP and APOA1.CETP mice. Mechanistically, CETP inhibition reduced the host proinflammatory response via attenuation of proinflammatory cytokine transcription and release. This effect was dependent on the presence of HDL, leading to attenuation of immune-mediated organ damage. In addition, CETP inhibition promoted monocyte activation in the blood prior to the onset of sepsis, resulting in accelerated macrophage recruitment to the lung and liver. In vitro experiments demonstrated that CETP inhibition significantly promoted the activation of proinflammatory signaling in peripheral blood mononuclear cells and THP1 cells in the absence of HDL; this may represent a mechanism responsible for improved bacterial clearance during sepsis. These findings provide evidence that CETP inhibition represents a potential approach to reduce mortality from pneumosepsis. Show less

The high-density lipoprotein hypothesis of atherosclerosis has been challenged by clinical trials of cholesteryl ester transfer protein (CETP) inhibitors, which failed to show significant reductions in cardiovascular events. Plasma levels of high-density lipoprotein cholesterol (HDL-C) decline drastically during sepsis, and this phenomenon is explained, in part, by the activity of CETP, a major determinant of plasma HDL-C levels. We tested the hypothesis that genetic or pharmacological inhibition of CETP would preserve high-density lipoprotein levels and decrease mortality in clinical cohorts and animal models of sepsis. We examined the effect of a gain-of-function variant in A fixed-effect meta-analysis of all 7 cohorts found that the Clinical genetics and humanized mouse models suggest that inhibiting CETP may preserve high-density lipoprotein levels and improve outcomes for individuals with sepsis. Show less

Sepsis is a common syndrome of multiorgan system dysfunction caused by a dysregulated inflammatory response to an infection and is associated with high rates of mortality. Plasma lipid and lipoprotein levels and composition change profoundly during sepsis and have emerged as both biomarkers and potential therapeutic targets for this condition. The purpose of this article is to review recent progress in the understanding of the molecular regulation of lipid metabolism during sepsis. Patients who experience greater declines in high-density lipoprotein during sepsis are at much greater risk of succumbing to organ failure and death. Although the causality of these findings remains unclear, all lipoprotein classes can sequester and prevent the excessive inflammation caused by pathogen-associated lipids during severe infections such as sepsis. This primordial innate immune function has been best characterized for high-density lipoproteins. Most importantly, results from human genetics and preclinical animal studies have suggested that several lipid treatment strategies, initially designed for atherosclerosis, may hold promise as therapies for sepsis. Lipid and lipoprotein metabolism undergoes significant changes during sepsis. An improved understanding of the molecular regulation of these changes may lead to new opportunities for the treatment of sepsis. Show less

High-density lipoprotein (HDL) cholesterol (HDL-C) levels decline during sepsis, and lower levels are associated with worse survival. However, the genetic mechanisms underlying changes in HDL-C during sepsis, and whether the relationship with survival is causative, are largely unknown. We hypothesized that variation in genes involved in HDL metabolism would contribute to changes in HDL-C levels and clinical outcomes during sepsis. We performed targeted resequencing of HDL-related genes in 200 patients admitted to an emergency department with sepsis (Early Infection cohort). We examined the association of genetic variants with HDL-C levels, 28-day survival, 90-day survival, organ dysfunction, and need for vasopressor or ventilatory support. Candidate variants were further assessed in the VASST (Vasopressin versus Norepinephrine Infusion in Patients with Septic Shock Trial) cohort (n = 632) and St. Paul's Hospital Intensive Care Unit 2 (SPHICU2) cohort (n = 203). We identified a rare missense variant in CETP (cholesteryl ester transfer protein gene; rs1800777-A) that was associated with significant reductions in HDL-C levels during sepsis. Carriers of the A allele (n = 10) had decreased survival, more organ failure, and greater need for organ support compared with noncarriers. We replicated this finding in the VASST and SPHICU2 cohorts, in which carriers of rs1800777-A (n = 35 and n = 12, respectively) had significantly reduced 28-day survival. Mendelian randomization was consistent with genetically reduced HDL levels being a causal factor for decreased sepsis survival. Our results identify CETP as a critical regulator of HDL levels and clinical outcomes during sepsis. These data point toward a critical role for HDL in sepsis. Show less

High-density cholesterol (HDL-C) levels are influenced by genetic variation in several genes. Low levels of HDL-C have been associated with increased risk of acute kidney injury (AKI). We investigated whether genetic polymorphisms in ten genes known to regulate HDL-C levels are associated with both HDL-C levels and AKI development during sepsis. Two cohorts were retrospectively analyzed: Derivation Cohort (202 patients with sepsis enrolled at the Emergency Department from 2011 to 2014 in Vancouver, Canada); Validation Cohort (604 septic shock patients enrolled into the Vasopressin in Septic Shock Trial (VASST)). Associations between HDL-related genetic polymorphisms and both HDL-C levels, and risk for clinically significant sepsis-associated AKI (AKI KDIGO stages 2 and 3) were evaluated. In the Derivation Cohort, one genetic variant in the Cholesteryl Ester Transfer Protein (CETP) gene, rs1800777 (allele A), was strongly associated with lower HDL-C levels (17.4 mg/dL vs. 32.9 mg/dL, P = 0.002), greater CETP mass (3.43 µg/mL vs. 1.32 µg/mL, P = 0.034), and increased risk of clinically significant sepsis-associated AKI (OR: 8.28, p = 0.013). Moreover, the same allele was a predictor of sepsis-associated AKI in the Validation Cohort (OR: 2.38, p = 0.020). Our findings suggest that CETP modulates HDL-C levels in sepsis. CETP genotype may identify patients at high-risk of sepsis-associated AKI. Show less