Can modulators of apolipoproteinB biogenesis serve as an alternate target for cholesterol-lowering drugs?

Understanding the molecular defects underlying cardiovascular disease is necessary for the development of therapeutics. The most common method to lower circulating lipids, which reduces the incidence of cardiovascular disease, is statins, but other drugs are now entering the clinic, some of which have been approved. Nevertheless, patients cannot tolerate some of these therapeutics, the drugs are costly, and/or the treatments are approved for only rare forms of disease. Efforts to find alternative treatments have focused on other factors, such as apolipoproteinB (apoB), which transports cholesterol in the blood stream. The levels of apoB are regulated by endoplasmic reticulum (ER) associated degradation as well as by a post ER degradation pathway in model systems, and we suggest that these events provide novel therapeutic targets. We discuss first how cardiovascular disease arises and how cholesterol is regulated, and then summarize the mechanisms of action of existing treatments for cardiovascular disease. We then review the apoB biosynthetic pathway, focusing on steps that might be amenable to therapeutic interventions.

Macadamia nut effects on cardiometabolic risk factors: a randomised trial.

We sought to examine the effects of daily consumption of macadamia nuts on body weight and composition, plasma lipids and glycaemic parameters in a free-living environment in overweight and obese adults at elevated cardiometabolic risk. Utilising a randomised cross-over design, thirty-five adults with abdominal obesity consumed their usual diet plus macadamia nuts (~15 % of daily calories) for 8 weeks (intervention) and their usual diet without nuts for 8 weeks (control), with a 2-week washout. Body composition was determined by bioelectrical impedance; dietary intake was assessed with 24-h dietary recalls. Consumption of macadamia nuts led to increased total fat and MUFA intake while SFA intake was unaltered. With mixed model regression analysis, no significant changes in mean weight, BMI, waist circumference, percent body fat or glycaemic parameters, and non-significant reductions in plasma total cholesterol of 2⋅1 % (-4⋅3 mg/dl; 95 % CI -14⋅8, 6⋅1) and low-density lipoprotein (LDL-C) of 4 % (-4⋅7 mg/dl; 95 % CI -14⋅3, 4⋅8) were observed. Cholesterol-lowering effects were modified by adiposity: greater lipid lowering occurred in those with overweight v. obesity, and in those with less than the median percent body fat. Daily consumption of macadamia nuts does not lead to gains in weight or body fat under free-living conditions in overweight or obese adults; non-significant cholesterol lowering occurred without altering saturated fat intake of similar magnitude to cholesterol lowering seen with other nuts. Clinical Trial Registry Number and Website: NCT03801837 https://clinicaltrials.gov/ct2/show/NCT03801837?term = macadamia + nut&draw = 2&rank = 1.

Non-high-density lipoprotein cholesterol, guideline targets, and population percentiles for secondary prevention in 1.3 million adults: the VLDL-2 study (very large database of lipids).

OBJECTIVES: This study sought to examine patient-level discordance between population percentiles of non-high-density lipoprotein cholesterol (HDL-C) and low-density lipoprotein cholesterol (LDL-C). BACKGROUND: Non-HDL-C is an alternative to LDL-C for risk stratification and lipid-lowering therapy. The justification for the present guideline-based non-HDL-C cutpoints of 30 mg/dl higher than the LDL-C cutpoints remains largely untested. METHODS: We assigned population percentiles to non-HDL-C and Friedewald-estimated LDL-C values of 1,310,440 U.S. adults with triglyceride levels <400 mg/dl who underwent lipid testing by vertical spin density gradient ultracentrifugation (Atherotech, Birmingham, Alabama) from 2009 to 2011. RESULTS: LDL-C cutpoints of 70, 100, 130, 160, and 190 mg/dl were in the same population percentiles as non-HDL-C values of 93, 125, 157, 190, and 223 mg/dl, respectively. Non-HDL-C values reclassified a significant proportion of patients within or to a higher treatment category compared with Friedewald LDL-C values, especially at LDL-C levels in the treatment range of high-risk patients and at triglyceride levels ≥150 mg/dl. Of patients with LDL-C levels <70 mg/dl, 15% had a non-HDL-C level ≥ 100 mg/dl (guideline-based cutpoint) and 25% had a non-HDL-C level ≥ 93 mg/dl (percentile-based cutpoint); if triglyceride levels were 150 to 199 mg/dl concurrently, these values were 22% and 50%, respectively. CONCLUSIONS: There is significant patient-level discordance between non-HDL-C and LDL-C percentiles at lower LDL-C and higher triglyceride levels, which has implications for the treatment of high-risk patients. Current non-HDL-C cutpoints for high-risk patients may need to be lowered to match percentiles of LDL-C cutpoints. Relatively small absolute reductions in non-HDL-C cutpoints result in substantial reclassification of patients to higher treatment categories with potential implications for risk assessment and treatment.

The association of elective hormone therapy with changes in lipids among glucose intolerant postmenopausal women in the diabetes prevention program.

OBJECTIVE: It is unclear how lipids change in response to lifestyle modification or metformin among postmenopausal glucose intolerant women using and not using hormone therapy (HT). We examined the one-year changes in lipids among postmenopausal, prediabetic women in the Diabetes Prevention Program (DPP), and whether changes were mediated by sex hormones. MATERIALS/METHODS: We performed a secondary analysis of a randomized controlled trial of 342 women who used HT at baseline and year 1 and 382 women who did not use HT at either time point. Interventions included intensive lifestyle (ILS) with goals of weight reduction of at least 7% of initial weight and 150 minutes per week of moderate intensity exercise, or metformin or placebo administered 850 mg up to twice a day. Women were not randomized to HT. Main outcome measures were changes between baseline and study year 1 in low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), and triglycerides. RESULTS: Compared to placebo, both ILS and metformin significantly reduced LDL-C and raised HDL-C among HT users, changes partially explained by change in estradiol and testosterone but independent of changes in waist circumference and 1/fasting insulin. In contrast, DPP interventions had no effect on LDL-C and HDL-C among non-HT users. ILS significantly lowered triglycerides among non-users but did not significantly change triglycerides among HT users. Metformin did not significantly change triglycerides among non-users but increased triglycerides among HT users. CONCLUSIONS: The beneficial effects of ILS and metformin on lowering LDL-C and raising HDL-C differ depending upon concurrent HT use.