SciCombinator

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Concept: Niacin

477

It is well known that total cholesterol becomes less of a risk factor or not at all for all-cause and cardiovascular (CV) mortality with increasing age, but as little is known as to whether low-density lipoprotein cholesterol (LDL-C), one component of total cholesterol, is associated with mortality in the elderly, we decided to investigate this issue.

Concepts: Cholesterol, Atherosclerosis, Cardiovascular disease, Low-density lipoprotein, Atheroma, Niacin

199

Background Loss-of-function variants in the angiopoietin-like 3 gene (ANGPTL3) have been associated with decreased plasma levels of triglycerides, low-density lipoprotein (LDL) cholesterol, and high-density lipoprotein (HDL) cholesterol. It is not known whether such variants or therapeutic antagonism of ANGPTL3 are associated with a reduced risk of atherosclerotic cardiovascular disease. Methods We sequenced the exons of ANGPTL3 in 58,335 participants in the DiscovEHR human genetics study. We performed tests of association for loss-of-function variants in ANGPTL3 with lipid levels and with coronary artery disease in 13,102 case patients and 40,430 controls from the DiscovEHR study, with follow-up studies involving 23,317 case patients and 107,166 controls from four population studies. We also tested the effects of a human monoclonal antibody, evinacumab, against Angptl3 in dyslipidemic mice and against ANGPTL3 in healthy human volunteers with elevated levels of triglycerides or LDL cholesterol. Results In the DiscovEHR study, participants with heterozygous loss-of-function variants in ANGPTL3 had significantly lower serum levels of triglycerides, HDL cholesterol, and LDL cholesterol than participants without these variants. Loss-of-function variants were found in 0.33% of case patients with coronary artery disease and in 0.45% of controls (adjusted odds ratio, 0.59; 95% confidence interval, 0.41 to 0.85; P=0.004). These results were confirmed in the follow-up studies. In dyslipidemic mice, inhibition of Angptl3 with evinacumab resulted in a greater decrease in atherosclerotic lesion area and necrotic content than a control antibody. In humans, evinacumab caused a dose-dependent placebo-adjusted reduction in fasting triglyceride levels of up to 76% and LDL cholesterol levels of up to 23%. Conclusions Genetic and therapeutic antagonism of ANGPTL3 in humans and of Angptl3 in mice was associated with decreased levels of all three major lipid fractions and decreased odds of atherosclerotic cardiovascular disease. (Funded by Regeneron Pharmaceuticals and others; ClinicalTrials.gov number, NCT01749878 .).

Concepts: Cholesterol, Myocardial infarction, Atherosclerosis, Cardiovascular disease, Low-density lipoprotein, Atheroma, Niacin, High-density lipoprotein

171

BACKGROUND: Global demographic changes have stimulated marked interest in the process of ageing. There has been, and will continue to be, an unrelenting rise in the number of the oldest old ( >85 years of age). Together with an ageing population there comes an increase in the prevalence of age related disease. Of the diseases of ageing, cardiovascular disease (CVD) has by far the highest prevalence. It is regarded that a finely tuned lipid profile may help to prevent CVD as there is a long established relationship between alterations to lipid metabolism and CVD risk. In fact elevated plasma cholesterol, particularly Low Density Lipoprotein Cholesterol (LDL-C) has consistently stood out as a risk factor for having a cardiovascular event. Moreover it is widely acknowledged that LDL-C may rise with age in both sexes in a wide variety of groups. The aim of this work was to use a whole-body mathematical model to investigate why LDL-C rises with age, and to test the hypothesis that mechanistic changes to cholesterol absorption and LDL-C removal from the plasma are responsible for the rise. The whole-body mechanistic nature of the model differs from previous models of cholesterol metabolism which have either focused on intracellular cholesterol homeostasis or have concentrated on an isolated area of lipoprotein dynamics. The model integrates both current and previously published data relating to molecular biology, physiology, ageing and nutrition in an integrated fashion. RESULTS: The model was used to test the hypothesis that alterations to the rate of cholesterol absorption and changes to the rate of removal of LDL-C from the plasma are integral to understanding why LDL-C rises with age. The model demonstrates that increasing the rate of intestinal cholesterol absorption from 50% to 80% by age 65 years can result in an increase of LDL-C by as much as 34mg/dL in a hypothetical male subject. The model also shows that decreasing the rate of hepatic clearance of LDL-C gradually to 50% by age 65 years can result in an increase of LDL-C by as much as 116mg/dL. CONCLUSIONS: Our model clearly demonstrates that of the two putative mechanisms that have been implicated in the dysregulation of cholesterol metabolism with age, alterations to the removal rate of plasma LDL-C has the most significant impact on cholesterol metabolism and small changes to the number of hepatic LDL receptors can result in a significant rise in LDL-C. This first whole-body systems based model of cholesterol balance could potentially be used as a tool to further improve our understanding of whole-body cholesterol metabolism and its dysregulation with age. Furthermore, given further fine tuning the model may help to investigate potential dietary and lifestyle regimes that have the potential to mitigate the effects aging has on cholesterol metabolism.

Concepts: Cholesterol, Nutrition, Atherosclerosis, Cardiovascular disease, Low-density lipoprotein, Atheroma, Niacin, High-density lipoprotein

109

Evidence that atopic eczema partly originates in utero is increasing, with some studies linking the risk of developing the condition with aspects of maternal diet during pregnancy. Nicotinamide, a naturally occurring nutrient that is maintained through the dietary intakes of vitamin B3 and tryptophan has been used in the treatment of some skin conditions including atopic eczema.

Concepts: Nutrition, Death, Niacin, Fat, Essential nutrient, Eczema, Psoriasis, Atopic dermatitis

69

PURPOSE Cinnamon has been studied in randomized controlled trials (RCTs) for its glycemic-lowering effects, but studies have been small and show conflicting results. A prior meta-analysis did not show significant results, but several RCTs have been published since then. We conducted an updated systematic review and meta-analysis of RCTs evaluating cinnamon’s effect on glycemia and lipid levels. METHODS MEDLINE, Embase, and Cochrane Central Register of Controlled Trials (CENTRAL) were searched through February 2012. Included RCTs evaluated cinnamon compared with control in patients with type 2 diabetes and reported at least one of the following: glycated hemoglobin (A1c), fasting plasma glucose, total cholesterol, low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), or triglycerides. Weighted mean differences (with 95% confidence intervals) for endpoints were calculated using random-effects models. RESULTS In a meta-analysis of 10 RCTs (n = 543 patients), cinnamon doses of 120 mg/d to 6 g/d for 4 to 18 weeks reduced levels of fasting plasma glucose (-24.59 mg/dL; 95% CI, -40.52 to -8.67 mg/dL), total cholesterol (-15.60 mg/dL; 95% CI, -29.76 to -1.44 mg/dL), LDL-C (-9.42 mg/dL; 95% CI, -17.21 to -1.63 mg/dL), and triglycerides (-29.59 mg/dL; 95% CI, -48.27 to -10.91 mg/dL). Cinnamon also increased levels of HDL-C (1.66 mg/dL; 95% CI, 1.09 to 2.24 mg/dL). No significant effect on hemoglobin A1c levels (-0.16%; 95%, CI -0.39% to 0.02%) was seen. High degrees of heterogeneity were present for all analyses except HDL-C (I(2) ranging from 66.5% to 94.72%). CONCLUSIONS The consumption of cinnamon is associated with a statistically significant decrease in levels of fasting plasma glucose, total cholesterol, LDL-C, and triglyceride levels, and an increase in HDL-C levels; however, no significant effect on hemoglobin A1c was found. The high degree of heterogeneity may limit the ability to apply these results to patient care, because the preferred dose and duration of therapy are unclear.

Concepts: Cholesterol, Atherosclerosis, Diabetes mellitus, Randomized controlled trial, Low-density lipoprotein, Niacin, Diabetes, Triglyceride

65

The B-vitamins comprise a group of eight water soluble vitamins that perform essential, closely inter-related roles in cellular functioning, acting as co-enzymes in a vast array of catabolic and anabolic enzymatic reactions. Their collective effects are particularly prevalent to numerous aspects of brain function, including energy production, DNA/RNA synthesis/repair, genomic and non-genomic methylation, and the synthesis of numerous neurochemicals and signaling molecules. However, human epidemiological and controlled trial investigations, and the resultant scientific commentary, have focused almost exclusively on the small sub-set of vitamins (B₉/B12/B₆) that are the most prominent (but not the exclusive) B-vitamins involved in homocysteine metabolism. Scant regard has been paid to the other B vitamins. This review describes the closely inter-related functions of the eight B-vitamins and marshals evidence suggesting that adequate levels of all members of this group of micronutrients are essential for optimal physiological and neurological functioning. Furthermore, evidence from human research clearly shows both that a significant proportion of the populations of developed countries suffer from deficiencies or insufficiencies in one or more of this group of vitamins, and that, in the absence of an optimal diet, administration of the entire B-vitamin group, rather than a small sub-set, at doses greatly in excess of the current governmental recommendations, would be a rational approach for preserving brain health.

Concepts: Metabolism, Nutrition, Niacin, Vitamin, Folic acid, B vitamins, Thiamine, Pyridoxine

62

Genetic findings reported approximately 9 years ago in the Journal indicated that rare sequence variants in the gene encoding proprotein convertase subtilisin-kexin type 9 serine protease (PCSK9) were associated with significantly lower long-term plasma levels of low-density lipoprotein (LDL) cholesterol.(1) The observed reduction in LDL cholesterol levels was similar to that attained with moderate-intensity statin therapy. The benefits of lifelong lowering of LDL cholesterol levels were substantial; a 47 to 88% lower risk of coronary heart disease was observed over a period of 15 years in middle-aged persons with such genetic polymorphisms. Further genetic studies indicated that PCSK9 . . .

Concepts: Cholesterol, Myocardial infarction, Atherosclerosis, Cardiovascular disease, Low-density lipoprotein, Statin, Atheroma, Niacin

58

Proprotein convertase subtilisin/kexin type 9 monoclonal antibodies can reduce low-density lipoprotein cholesterol (LDL-C) to very low levels when added to background lipid-lowering therapy.

Concepts: Cholesterol, Atherosclerosis, Cardiovascular disease, Low-density lipoprotein, Atheroma, Niacin, Lipoprotein

37

In early June, the Endocrinologic and Metabolic Drugs Advisory Committee of the Food and Drug Administration (FDA), on which we serve, met to consider marketing applications for the new molecular entities alirocumab and evolocumab on the basis of their ability to lower low-density lipoprotein (LDL) cholesterol levels and their effects on other lipid fractions in patients at risk for cardiovascular disease. These first-in-class medications are fully humanized monoclonal antibodies that inactivate proprotein convertase subtilisin-kexin type 9 (PCSK9). That inactivation results in decreased LDL-receptor degradation, increased recirculation of the receptor to the surface of hepatocytes, and consequent lowering of LDL cholesterol . . .

Concepts: Cholesterol, Myocardial infarction, Atherosclerosis, Cardiovascular disease, Low-density lipoprotein, Atheroma, Monoclonal antibodies, Niacin

28

Ten blue-neck male ostriches (Struthio camelus) were fed Prosopis farcta beans throughout a 30-day experiment. Blood samples were collected from ostriches on days 0 and 30 to measure levels of high-density lipoprotein (HDL) cholesterol, low-density lipoprotein (LDL) cholesterol, triglyceride, total serum protein, albumin, globulin, cholesterol, calcium, inorganic phosphorus, the activity of aspartate aminotransferase, alanine aminotransferase, and γ-glutamyl transferase (γ-GT). From days 0 to 30, HDL cholesterol, total protein, and globulins levels increased significantly whereas LDL cholesterol, inorganic phosphorus, and γ-GT activity decreased significantly.

Concepts: Cholesterol, Atherosclerosis, Low-density lipoprotein, Atheroma, Lipid disorders, Niacin, High-density lipoprotein, Lipoproteins