Treating lipid abnormalities in patients with type 2 diabetes mellitus

Fibrates for primary prevention of cardiovascular disease events

BACKGROUND

Fibrates are effective for modifying atherogenic dyslipidaemia, and particularly for lowering serum triglycerides. However, evidence that fibrates reduce mortality and morbidity associated with cardiovascular disease (CVD), or overall mortality and morbidity, in the primary prevention of CVD is lacking.

OBJECTIVES

This Cochrane Review and meta-analysis aimed to evaluate the clinical benefits and harms of fibrates versus placebo or usual care or fibrates plus other lipid-modifying drugs versus other lipid-modifying drugs alone for the primary prevention of cardiovascular disease (CVD) morbidity and mortality.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE (Ovid), Embase (Ovid), CINAHL (EBSCO), and Web of Science (all from inception to 19 May 2016). We searched four clinical trial registers (last searched on 3 August 2016) with the help of an experienced professional librarian. We searched the databases to identify randomised controlled trials (RCTs) evaluating the clinical effects of fibrate therapy in the primary prevention of CVD events. We did not impose any language restrictions.

SELECTION CRITERIA

We aimed to include all RCTs comparing the effects of fibrate monotherapy versus placebo or usual care, or fibrates plus other lipid-modifying drugs versus other lipid-modifying drugs alone. Included studies had a follow-up of at least six months for the primary prevention of CVD events. We excluded trials with clofibrate, because it was withdrawn from the market in 2002.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened titles and abstracts for potential study inclusion. Two review authors independently retrieved the full-text papers and extracted data. Disagreements were resolved by consensus. We calculated risk ratios (RRs) and accompanying 95% confidence intervals (CIs) for aggregate data on primary and secondary outcomes. We tested for heterogeneity with the Cochrane Q-test and used the I2 statistic to measure inconsistency of treatment effects across studies. Using the GRADE approach, we assessed the quality of the evidence and used the GRADE profiler software (GRADEpro GDT) to import data from Review Manager 5 to create 'Summary of findings' tables.

MAIN RESULTS

We identified six eligible trials including 16,135 individuals. The mean age of trial populations varied across trials; between 47.3 and 62.3 years. Four trials included individuals with diabetes mellitus type 2 only. The mean treatment duration and follow-up of participants across trials was 4.8 years. We judged the risks of selection and performance bias to be low; risks of detection bias, attrition bias, and reporting bias were unclear. Reporting of adverse effects by included trials was very limited; that is why we used discontinuation of therapy due to adverse effects as a proxy for adverse effects. Patients treated with fibrates had a reduced risk for the combined primary outcome of CVD death, non-fatal myocardial infarction, or non-fatal stroke compared to patients on placebo (risk ratio (RR) 0.84, 95% confidence interval (CI) 0.74 to 0.96; participants = 16,135; studies = 6; moderate-quality of evidence). For secondary outcomes we found RRs for fibrate therapy compared with placebo of 0.79 for combined coronary heart disease death or non-fatal myocardial infarction (95% CI 0.68 to 0.92; participants = 16,135; studies = 6; moderate-quality of evidence); 1.01 for overall mortality (95% CI 0.81 to 1.26; participants = 8471; studies = 5; low-quality of evidence); 1.01 for non-CVD mortality (95% CI 0.76 to 1.35; participants = 8471; studies = 5; low-quality of evidence); and 1.38 for discontinuation of therapy due to adverse effects (95% CI 0.71 to 2.68; participants = 4805; studies = 3; I2 = 74%; very low-quality of evidence). Data on quality of life were not available from any trial. Trials that evaluated fibrates in the background of statins (2 studies) showed no benefits in preventing cardiovascular events.

AUTHORS' CONCLUSIONS

Moderate-quality evidence suggests that fibrates lower the risk for cardiovascular and coronary events in primary prevention, but the absolute treatment effects in the primary prevention setting are modest (absolute risk reductions < 1%). There is low-quality evidence that fibrates have no effect on overall or non-CVD mortality. Very low-quality evidence suggests that fibrates are not associated with increased risk for adverse effects.

Genome-wide screen for modulation of hepatic apolipoprotein A-I (ApoA-I) secretion

Control of plasma cholesterol levels is a major therapeutic strategy for management of coronary artery disease (CAD). Although reducing LDL cholesterol (LDL-c) levels decreases morbidity and mortality, this therapeutic intervention only translates into a 25-40% reduction in cardiovascular events. Epidemiological studies have shown that a high LDL-c level is not the only risk factor for CAD; low HDL cholesterol (HDL-c) is an independent risk factor for CAD. Apolipoprotein A-I (ApoA-I) is the major protein component of HDL-c that mediates reverse cholesterol transport from tissues to the liver for excretion. Therefore, increasing ApoA-I levels is an attractive strategy for HDL-c elevation. Using genome-wide siRNA screening, targets that regulate hepatocyte ApoA-I secretion were identified through transfection of 21,789 siRNAs into hepatocytes whereby cell supernatants were assayed for ApoA-I. Approximately 800 genes were identified and triaged using a convergence of information, including genetic associations with HDL-c levels, tissue-specific gene expression, druggability assessments, and pathway analysis. Fifty-nine genes were selected for reconfirmation; 40 genes were confirmed. Here we describe the siRNA screening strategy, assay implementation and validation, data triaging, and example genes of interest. The genes of interest include known and novel genes encoding secreted enzymes, proteases, G-protein-coupled receptors, metabolic enzymes, ion transporters, and proteins of unknown function. Repression of farnesyltransferase (FNTA) by siRNA and the enzyme inhibitor manumycin A caused elevation of ApoA-I secretion from hepatocytes and from transgenic mice expressing hApoA-I and cholesterol ester transfer protein transgenes. In total, this work underscores the power of functional genetic assessment to identify new therapeutic targets.

Achievement of lipid targets with the combination of rosuvastatin and fenofibric Acid in patients with type 2 diabetes mellitus

Objective

The objective of this study was to assess the proportion of patients with type 2 diabetes mellitus (T2DM) attaining individual and combined targets of low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), triglycerides (TG), non-HDL-C, and apolipoprotein B (ApoB) after treatment with rosuvastatin (R) + fenofibric acid (FA) compared with corresponding-dose R monotherapy.

Methods

This post hoc analysis evaluated data from the T2DM subset of patients with mixed dyslipidemia (LDL-C ≥130 mg/dL, HDL-C <40/50 mg/dL in men/women, and TG ≥150 mg/dL) from 2 randomized studies. Patients included in the analysis (N = 456) were treated with R (5, 10, or 20 mg), FA 135 mg, or R (5, 10, or 20 mg) + FA 135 mg for 12 weeks. Attainment of LDL-C <100 mg/dL, HDL-C >40/50 mg/dL in men/women, TG <150 mg/dL, non-HDL-C <130 mg/dL, ApoB <90 mg/dL, and the combined targets of these parameters was assessed.

Results

Treatment with R + FA resulted in a significantly higher proportion of patients achieving optimal levels of HDL-C (46.8% vs. 20.8%, P = 0.009 for R 10 mg + FA), TG (60.0% vs. 34.0%, P = 0.02 for R 10 mg + FA; 54.0% vs. 26.4%, P = 0.005 for R 20 mg + FA), non-HDL-C (55.1% vs. 36.4%, P = 0.04 for R 5 mg + FA), ApoB (58.0% vs. 36.4%, P = 0.02 for R 5 mg + FA); and the combined targets of LDL-C, HDL-C, and TG (28.3% vs. 8.3%, P = 0.02 for R 10 mg + FA) and all 5 parameters (26.1% vs. 8.3%, P = 0.03 for R 10 mg + FA) than corresponding-dose R monotherapies.

Conclusions

A significantly greater proportion of T2DM patients achieved individual and combined lipid targets when treated with the combination of R + FA than corresponding-dose R monotherapies.

Clinical studies of red clover (Trifolium pratense) dietary supplements in menopause: a literature review

Red clover (Trifolium pratense L., Fabaceae) botanical dietary supplements have received much attention recently for their potential use in the treatment of menopause symptoms, maintenance/improvement of bone and cardiovascular health, and reported benign effects on the breast and endometrium. Literature searches of four computerized databases were run to identify clinical studies of red clover botanical dietary supplements. The manufacturer of the red clover products used in the majority of the studies was contacted for unpublished information and/or clarification regarding the chemical content of their products. Red clover studies were reviewed that pertained to women's health or menopause. Clinical evidence is presently lacking to support the efficacy of semipurified red clover isoflavone extracts for alleviation of climacteric vasomotor symptoms or reduction of low-density lipoprotein levels in the blood. Furthermore, the safety of use of red clover isoflavone supplements in patients with breast or endometrial cancer has not been established. Limited evidence suggests possible efficacy in maintenance of bone health and improvement of arterial compliance, a risk factor for atherosclerosis. This literature review covers red clover botanical dietary supplement clinical studies having a possible impact on the health care of mature and menopausal women, and provides historical perspective regarding the traditional uses of red clover.

Endocannabinoid blockade for improving glycemic control and lipids in patients with type 2 diabetes mellitus

Rimonabant significantly reduces weight and waist circumference and improves dyslipidemias in overweight and obese patients without diabetes mellitus. Numerous other metabolic changes, including reduced prevalence of the metabolic syndrome and associated cardiovascular disease (CVD) risk factors, reduced fasting glucose, and elevated adiponectin, have been demonstrated with the administration of rimonabant. The Rimonabant-in-Obesity (RIO)-Diabetes trial studied the safety and efficacy of rimonabant in overweight and obese patients with type 2 diabetes who were treated with metformin or sulfonylureas. RIO-Diabetes was a 1-year, randomized, double-blind, placebo-controlled, parallel-group study of 1,047 overweight/obese patients with type 2 diabetes in 151 centers in 11 countries. The body mass index of participants ranged from 27 to 40. Glycosylated hemoglobin (HbA1c) at screening ranged from 6.5% to 10.0%. All patients were receiving either metformin or sulfonylurea therapy and were asked to follow a hypocaloric diet (600 kcal/day deficit [1 kcal = 4.2 kJ]) for the duration of the trial. After a 4-week placebo plus diet run-in period, patients were randomized to receive placebo or rimonabant 5 mg or 20 mg once daily. At 1 year, absolute change in weight from baseline in the intention-to-treat, last observation carried forward analysis of the rimonabant 5 mg and 20 mg groups, respectively, was loss of 2.3 kg and 5.3 kg compared with 1.4 kg in the placebo group (P = 0.013 and P <0.001, respectively). Waist circumference was significantly decreased in the rimonabant 5-mg and 20-mg groups by 2.9 cm and 5.2 cm compared with 1.9 cm in the placebo group (P = 0.034 and P <0.001, respectively). HbA1c reductions of 0.1% and 0.6% were significant in the rimonabant 5-mg and 20-mg groups (P = 0.034 and P <0.001, respectively). Some 57% of the improvements in HbA(1c) and high-density lipoprotein cholesterol could not be attributed to observed weight loss. Compared with placebo, rimonabant 20 mg also demonstrated significant improvements in the prevalence of metabolic syndrome and improvement in its constituents, as well as systolic blood pressure and C-reactive protein levels (assay by ICON Laboratories, Farmingdale, NY and Dublin, Ireland). Rimonabant is the first selective cannabinoid1 blocker studied for type 2 diabetes and associated CVD risk factor therapy. Its ability to improve the numerous metabolic pathologies associated with diabetes and CVD risk and concomitantly to reduce weight and waist circumference introduces a strongly positive new dynamic in type 2 diabetes treatment. Its multifactorial mechanisms warrant further investigation and may provide insights into other pathologies.

Antioxidative Effect of Conjugated Linolenic Acid in Diabetic and Non-Diabetic Blood: an in vitro Study

The present study examined the in vitro antioxidant activity of conjugated octadecatrienoic fatty acid (9cis, 11 trans, 13 trans-18:3), alpha-eleostearic acid present in karela seed oil (Momordica charantia) at about 55% level. The in vitro antioxidant properties of alpha-eleostearic acid are investigated on oxidative modification of human plasma, low-density lipoprotein (LDL) and erythrocyte membrane lipid. Blood samples are collected from diabetic and non-diabetic (normal) healthy individuals. alpha-eleostearic acid is added at 0.05% and 0.1% concentrations to plasma, LDL and erythrocyte membrane isolated from the respective blood samples and peroxidations are determined against control samples. A significant increase of respective peroxidation levels has been observed in diabetic control blood than the non-diabetic control blood. alpha-eleostearic acid has decreased lipid peroxidation level against control samples in a dose dependent manner. The present findings suggest that CLnA, 9cis, 11trans, 13trans-18:3 is a potentially effective antioxidant that can protect plasma, low density lipoprotein and erythrocyte membrane from oxidation which may be effective in reducing the risk of coronary heart disease in diabetes mellitus.

Genome scan for quantitative trait loci influencing HDL levels: evidence for multilocus inheritance in familial combined hyperlipidemia

Several genome scans in search of high-density lipoprotein (HDL) quantitative trait loci (QTLs) have been performed. However, to date the actual identification of genes implicated in the regulation of common forms of HDL abnormalities remains unsuccessful. This may be due, in part, to the oligogenic and multivariate nature of HDL regulation, and potentially, pleiotropy affecting HDL and other lipid-related traits. Using a Bayesian Markov Chain Monte Carlo (MCMC) approach, we recently provided evidence of linkage of HDL level variation to the APOA1-C3-A4-A5 gene complex, in familial combined hyperlipidemia pedigrees, with an estimated number of two to three large QTLs remaining to be identified. We also presented results consistent with pleiotropy affecting HDL and triglycerides at the APOA1-C3-A4-A5 gene complex. Here we use the same MCMC analytic strategy, which allows for oligogenic trait models, as well as simultaneous incorporation of covariates, in the context of multipoint analysis. We now present results from a genome scan in search for the additional HDL QTLs in these pedigrees. We provide evidence of linkage for additional HDL QTLs on chromosomes 3p14 and 13q32, with results on chromosome 3 further supported by maximum parametric and variance component LOD scores of 3.0 and 2.6, respectively. Weaker evidence of linkage was also obtained for 7q32, 12q12, 14q31-32 and 16q23-24.

PPARs: therapeutic targets for metabolic disease

The three peroxisome-proliferator-activated receptor (PPAR) subtypes, PPAR-gamma, PPAR-alpha and PPAR-delta, are nuclear receptors that have been the focus of extensive research during the past decade. These receptors function as lipid sensors that coordinately regulate the expression of large gene arrays and, thereby, modulate important metabolic events. They are also the targets of drugs that are effective in the treatment of metabolic disorders (type 2 diabetes mellitus and atherosclerosis) that afflict industrialized societies at epidemic levels. Ongoing research indicates that modulation of PPAR activity might be an effective therapy for additional maladies associated with the metabolic syndrome, including obesity. Novel PPAR ligands are now being developed that possess broader efficacies and improved tolerability compared with currently available therapeutic agents.

PPAR ligands: potential therapies for metabolic syndrome

Metabolic syndrome (MS), a condition characterized by multiple related clinical disorders including insulin resistance, central obesity, hyperlipidemia, hypertension, and heart disease, is an increasingly prevalent disease in industrialized societies. The intense research interest in the peroxisome proliferator-activated receptors (PPARs), by both the pharmaceutical industry and academia, stems largely from the well-documented therapeutic actions of their synthetic agonists in alleviating several of the maladies associated with MS. This report focuses on the current understanding of the mechanisms of action of PPAR agents and their clinical use in the context of MS.

Effects of Hilsa ilisa fish oil on the atherogenic lipid profile and glycaemic status of streptozotocin-treated type 1 diabetic rats

1. The effects of oral administration of Hilsa (Hilsa ilisa) fish oil (1 g oil/kg bodyweight per day) on the lipid profile, platelet aggregation, anti-oxidative status and glycaemic control of streptozotocin (STZ; 90 mg/kg bodyweight)-treated type 1 diabetic rats were compared with those in fish oil-treated or untreated non-diabetic rats. 2. After 3 weeks of fish oil feeding, plasma total cholesterol decreased in both the non-diabetic and diabetic rats by 35 and approximately 10%, respectively, and triglyceride fell by 69 and 20%, respectively, compared with control rats. 3. Fish oil feeding decreased non-esterified fatty acids (NEFA) by 29% in diabetic rats but the NEFA level in non-diabetic rats was unaffected. 4. In non-diabetic and diabetic rats, platelet aggregation decreased by 49 and 37%, respectively, and total anti-oxidant status increased by 18 and 17%, respectively, after fish oil feeding. 5. Insulin levels increased by 27% in the fish oil-fed non-diabetic rats, whereas insulin levels were markedly decreased in diabetic rats. Glucose levels were not altered at all and fructosamine levels decreased by 29% only in fish oil-fed diabetic rats. 6. The results of the present study suggest that Hilsa ilisa fish oil may ameliorate the atherogenic lipid profile, platelet hyperaggregation and the anti-oxidative defence of STZ-diabetic rats and the amelioration is thought to be independent of the effects of Hilsa on glycaemic control.