Combination therapy with statin and fibrate in patients with dyslipidemia associated with insulin resistance, metabolic syndrome and type 2 diabetes mellitus

An Overview of the Role of Peroxisome Proliferator-activated Receptors in Liver Diseases

Peroxisome proliferator-activated receptors (PPARs) are a superfamily of nuclear transcription receptors, consisting of PPARα, PPARγ, and PPARβ/δ, which are highly expressed in the liver. They control and modulate the expression of a large number of genes involved in metabolism and energy homeostasis, oxidative stress, inflammation, and even apoptosis in the liver. Therefore, they have critical roles in the pathophysiology of hepatic diseases. This review provides a general insight into the role of PPARs in liver diseases and some of their agonists in the clinic.

Role of peroxisome proliferator-activated receptors in stroke prevention and therapy-The best is yet to come?

Role of peroxisome proliferator-activated receptors (PPARs) in the pathophysiology of stroke and protective effects of PPAR ligands have been widely investigated in the last 20 years. Activation of all three PPAR isoforms, but especially PPAR-γ, was documented to limit postischemic injury in the numerous in vivo, as well as in in vitro studies. PPARs have been demonstrated to act on multiple mechanisms and were shown to activate multiple protective pathways related to inflammation, apoptosis, BBB protection, neurogenesis, and oxidative stress. The aim of this review was to summarize two decades of PPAR research in stroke with emphasis on in vivo animal studies. We focus on each PPAR receptor separately and detail their implication in stroke. This review also discusses recent clinical efforts in the field and the epidemiological data with regard to role of PPAR polymorphisms in susceptibility to stroke, and tries to draw conclusions and describe future perspectives.

Effect of Hesperidin on Cardiovascular Disease Risk Factors: The Role of Intestinal Microbiota on Hesperidin Bioavailability

Recently, hesperidin, a flavonone mainly present in citrus fruits, has emerged as a new potential therapeutic agent able to modulate several cardiovascular diseases (CVDs) risk factors. Animal and in vitro studies demonstrate beneficial effects of hesperidin and its derived compounds on CVD risk factors. Thus, hesperidin has shown glucose-lowering and anti-inflammatory properties in diabetic models, dyslipidemia-, atherosclerosis-, and obesity-preventing effects in CVDs and obese models, and antihypertensive and antioxidant effects in hypertensive models. However, there is still controversy about whether hesperidin could contribute to ameliorate glucose homeostasis, lipid profile, adiposity, and blood pressure in humans, as evidenced by several clinical trials reporting no effects of treatments with this flavanone or with orange juice on these cardiovascular parameters. In this review, we focus on hesperidin's beneficial effects on CVD risk factors, paying special attention to the high interindividual variability in response to hesperidin-based acute and chronic interventions, which can be partly attributed to differences in gut microbiota. Based on the current evidence, we suggest that some of hesperidin's contradictory effects in human trials are partly due to the interindividual hesperidin variability in its bioavailability, which in turn is highly dependent on the α-rhamnosidase activity and gut microbiota composition.

Diagnostic imaging in the management of patients with metabolic syndrome

Metabolic syndrome (MetS) is the constellation of metabolic risk factors that might foster development of type 2 diabetes and cardiovascular disease. Abdominal obesity and insulin resistance play a prominent role among all metabolic traits of MetS. Because intervention including weight loss can reduce these morbidity and mortality in MetS, early detection of the severity and complications of MetS could be useful. Recent advances in imaging modalities have provided significant insight into the development and progression of abdominal obesity and insulin resistance, as well as target organ injuries. The purpose of this review is to summarize advances in diagnostic imaging modalities in MetS that can be applied for evaluating each components and target organs. This may help in early detection, monitoring target organ injury, and in turn developing novel therapeutic target to alleviate and avert them.

Efficacy of statin monotherapy or in combination with coenzyme a capsule in patients with metabolic syndrome and mixed dyslipidemia

BACKGROUND

Patients with metabolic syndrome are at increased risk for cardiovascular disease. Combination lipid-lowering therapy is often needed in patients with metabolic syndrome and mixed dyslipidemia. The aim of this study was to compare the effect of statin combined with a new hypolipidemic agent, coenzyme A (CoA) with moderate-dose statin monotherapy in subjects with metabolic syndrome and mixed dyslipidemia by evaluating data from a subgroup of patients with metabolic syndrome and mixed dyslipidemia from a previously conducted randomized study.

METHODS

In the present post hoc analysis, 212 patients were included, receiving statin monotherapy (n = 94) or statin combined with CoA 400 U/day (n = 118) for 8 weeks. The lipoprotein profile was determined at baseline and week 8 visits. Attainment of low-density lipoprotein-cholesterol (LDL-C) < 100 mg/dL, non-high-density lipoprotein-cholesterol (HDL-C) < 130 mg/dL, and the combined goal of these two parameters was also evaluated.

RESULTS

The mean percent change was more prominent with CoA plus statin compared with placebo plus statin in triglyceride (TG) (-32.5% vs. -8.7%, respectively; P = 0.0002), total cholesterol (-9.6% vs. -3.6%, P = 0.013), LDL-C (-7.5% vs. 2.1%, P = 0.033), and non-HDL-C (-14.3% vs. -6.4%, P = 0.011). Treatment with CoA plus statin resulted in larger percentages of participants attaining lipid goals for LDL-C (70.3% vs. 56.4%, P = 0.044), non-HDL-C (60.2% vs. 45.7%, P = 0.039), and the combined goal of LDL-C and non-HDL-C (57.6% vs. 42.6%, P = 0.038) than statin monotherapy.

CONCLUSION

These results demonstrate that CoA plus statin therapy was more effective in improving lipoprotein parameters than statin alone in patients with metabolic syndrome and mixed hyperlipidemia.

Effect of combination therapy with fenofibrate and simvastatin on postprandial lipemia in the ACCORD lipid trial

OBJECTIVE

The Action to Control Cardiovascular Risk in Diabetes lipid study (ACCORD Lipid), which compared the effects of simvastatin plus fenofibrate (FENO-S) versus simvastatin plus placebo (PL-S) on cardiovascular disease outcomes, measured only fasting triglyceride (TG) levels. We examined the effects of FENO-S on postprandial (PP) lipid and lipoprotein levels in a subgroup of ACCORD Lipid subjects.

RESEARCH DESIGN AND METHODS

We studied 139 subjects (mean age of 61 years, 40% female, and 76% Hispanic or black) in ACCORD Lipid, from a total 529 ACCORD Lipid subjects in the Northeast Clinical Network. PP plasma TG, apolipoprotein (apo)B48, and apoCIII were measured over 10 h after an oral fat load.

RESULTS

The PP TG incremental area under the curve (IAUC) above fasting (median and interquartile range [mg/dL/h]) was 572 (352-907) in the FENO-S group versus 770 (429-1,420) in the PL-S group (P = 0.008). The PP apoB48 IAUC (mean ± SD [μg/mL/h]) was also reduced in the FENO-S versus the PL-S group (23.2 ± 16.3 vs. 35.2 ± 28.6; P = 0.008). Fasting TG levels on the day of study were correlated with PP TG IAUC (r = 0.73 for FENO-S and r = 0.62 for PL-S; each P < 0.001). However, the fibrate effect on PP TG IAUC was a constant percentage across the entire range of fasting TG levels, whereas PP apoB48 IAUC was only reduced when fasting TG levels were increased.

CONCLUSIONS

FENO-S lowered PP TG similarly in all participants compared with PL-S. However, levels of atherogenic apoB48 particles were reduced only in individuals with increased fasting levels of TG. These results may have implications for interpretation of the overall ACCORD Lipid trial, which suggested benefit from FENO-S only in dyslipidemic individuals.

Citrus flavonoids and lipid metabolism

PURPOSE OF REVIEW

Citrus flavonoids are polyphenolic compounds with powerful biological properties. This review aims to summarize recent advances towards understanding the ability of citrus flavonoids to regulate lipid metabolism and other metabolic parameters relevant to the metabolic syndrome, type 2 diabetes and cardiovascular disease.

RECENT FINDINGS

Citrus flavonoids, including naringenin, hesperidin, nobiletin and tangeretin, have emerged as promising therapeutic agents for the treatment of metabolic dysregulation. Epidemiological studies report that intake of citrus flavonoid-containing foods attenuates cardiovascular diseases. Experimental and a limited number of clinical studies reveal lipid-lowering, insulin-sensitizing, antihypertensive and anti-inflammatory properties. In animal models, citrus flavonoid supplements prevent hepatic steatosis, dyslipidemia and insulin sensitivity primarily through inhibition of hepatic fatty acid synthesis and increased fatty acid oxidation. Citrus flavonoids blunt the inflammatory response in metabolically important tissues including liver, adipose tissue, kidney and the aorta. The mechanisms underlying flavonoid-induced metabolic regulation have not been completely established. In mouse models, citrus flavonoids show marked suppression of atherogenesis through improved metabolic parameters and also through direct impact on the vessel wall.

SUMMARY

These recent studies suggest an important role of citrus flavonoids in the treatment of dyslipidemia, insulin resistance, hepatic steatosis, obesity and atherosclerosis. The favorable outcomes are achieved through multiple mechanisms. Human studies focussed on dose, bioavailability, efficacy and safety are required to propel the use of these promising therapeutic agents into the clinical arena.

Effect of fenofibrate and atorvastatin on VLDL apoE metabolism in men with the metabolic syndrome

We examined the effects of fenofibrate and atorvastatin on very low density lipoprotein (VLDL) apolipoprotein (apo)E metabolism in the metabolic syndrome (MetS). We studied 11 MetS men in a randomized, double-blind, crossover trial. VLDL-apoE kinetics were examined using stable isotope methods and compartmental modeling. Compared with placebo, fenofibrate (200 mg/day) and atorvastatin (40 mg/day) decreased plasma apoE concentrations (P < 0.05). Fenofibrate decreased VLDL-apoE concentration and production rate (PR) and increased VLDL-apoE fractional catabolic rate (FCR) compared with placebo (P < 0.05). Compared with placebo, atorvastatin decreased VLDL-apoE concentration and increased VLDL-apoE FCR (P < 0.05). Fenofibrate and atorvastatin had comparable effects on VLDL-apoE concentration. The increase in VLDL-apoE FCR with fenofibrate was 22% less than that with atorvastatin (P < 0.01). With fenofibrate, the change in VLDL-apoE concentration was positively correlated with change in VLDL-apoB concentration, and negatively correlated with change in VLDL-apoB FCR. In MetS, fenofibrate and atorvastatin decreased plasma apoE concentrations. Fenofibrate decreased VLDL-apoE concentration by lowering VLDL-apoE production and increasing VLDL-apoE catabolism. By contrast, atorvastatin decreased VLDL-apoE concentration chiefly by increasing VLDL-apoE catabolism. Our study provides new insights into the mechanisms of action of two different lipid-lowering therapies on VLDL-apoE metabolism in MetS.

Preservation of metabolic flexibility in skeletal muscle by a combined use of n-3 PUFA and rosiglitazone in dietary obese mice

Insulin resistance, the key defect in type 2 diabetes (T2D), is associated with a low capacity to adapt fuel oxidation to fuel availability, i.e., metabolic inflexibility. This, in turn, contributes to a further damage of insulin signaling. Effectiveness of T2D treatment depends in large part on the improvement of insulin sensitivity and metabolic adaptability of the muscle, the main site of whole-body glucose utilization. We have shown previously in mice fed an obesogenic high-fat diet that a combined use of n-3 long-chain polyunsaturated fatty acids (n-3 LC-PUFA) and thiazolidinediones (TZDs), anti-diabetic drugs, preserved metabolic health and synergistically improved muscle insulin sensitivity. We investigated here whether n-3 LC-PUFA could elicit additive beneficial effects on metabolic flexibility when combined with a TZD drug rosiglitazone. Adult male C57BL/6N mice were fed an obesogenic corn oil-based high-fat diet (cHF) for 8 weeks, or randomly assigned to various interventions: cHF with n-3 LC-PUFA concentrate replacing 15% of dietary lipids (cHF+F), cHF with 10 mg rosiglitazone/kg diet (cHF+ROSI), cHF+F+ROSI, or chow-fed. Indirect calorimetry demonstrated superior preservation of metabolic flexibility to carbohydrates in response to the combined intervention. Metabolomic and gene expression analyses in the muscle suggested distinct and complementary effects of the interventions, with n-3 LC-PUFA supporting complete oxidation of fatty acids in mitochondria and the combination with n-3 LC-PUFA and rosiglitazone augmenting insulin sensitivity by the modulation of branched-chain amino acid metabolism. These beneficial metabolic effects were associated with the activation of the switch between glycolytic and oxidative muscle fibers, especially in the cHF+F+ROSI mice. Our results further support the idea that the combined use of n-3 LC-PUFA and TZDs could improve the efficacy of the therapy of obese and diabetic patients.

Non-lipid effects of rosuvastatin-fenofibrate combination therapy in high-risk Asian patients with mixed hyperlipidemia

OBJECTIVE

The aim of this study is to compare the non-lipid effects of rosuvastatin-fenofibrate combination therapy with rosuvastatin monotherapy in high-risk Asian patients with mixed hyperlipidemia.

METHODS

A total of 236 patients were initially screened. After six weeks of diet and life style changes, 180 of these patients were randomly assigned to receive one of two regimens: rosuvastatin 10 mg plus fenofibrate 160 mg or rosuvastatin 10 mg. The primary outcome variables were the incidences of muscle or liver enzyme elevation. The patients were followed for 24 weeks during drug treatment and for an additional four weeks after drug discontinuation.

RESULTS

The rates of the primary outcome variables were similar between the two groups (2.8% and 3.9% in the combination and the rosuvastatin groups, respectively, p=1.00). The combination group had more, but not significantly, common treatment-related adverse events (AEs) (13.3% and 5.6%, respectively) and drug discontinuation due to AEs (10.0% and 3.3%, respectively) than the rosouvastatin group. Combination therapy was associated with higher elevations in homocysteine, blood urea nitrogen, and serum creatinine, whereas elevation in alanine aminotransferase was greater in the rosuvastatin group. Leukocyte count and hemoglobin level decreased to a greater extent in the combination group. The combination group showed greater reductions in TG and elevation in HDL-cholesterol.

CONCLUSION

In our study population, the rosuvastatin-fenofibrate combination resulted in comparable incidences of myo- or hepatotoxicity as rosuvastatin monotherapy. However, this combination may need to be used with caution in individuals with underlying pathologies such as renal dysfunction (NCT01414803).

Unmasking differential effects of rosiglitazone and pioglitazone in the combination treatment with n-3 fatty acids in mice fed a high-fat diet

Combining pharmacological treatments and life style interventions is necessary for effective therapy of major diseases associated with obesity, which are clustered in the metabolic syndrome. Acting via multiple mechanisms, combination treatments may reduce dose requirements and, therefore, lower the risk of adverse side effects, which are usually associated with long-term pharmacological interventions. Our previous study in mice fed high-fat diet indicated additivity in preservation of insulin sensitivity and in amelioration of major metabolic syndrome phenotypes by the combination treatment using n-3 long-chain polyunsaturated fatty acids (n-3 LC-PUFA) and rosiglitazone, i.e. an anti-diabetic drug of the thiazolidinedione (TZD) family. We investigated here whether pioglitazone, a TZD-drug in clinical use, could elicit the additive beneficial effects when combined with n-3 LC-PUFA. Adult male mice (C57BL/6N) were fed an obesogenic corn oil-based high-fat diet (cHF) for 8 weeks, or randomly assigned to various dietary treatments (i) cHF+F, cHF with n-3 LC-PUFA concentrate replacing 15% of dietary lipids; (ii) cHF+ROSI, cHF with 10 mg rosiglitazone/kg diet; (iii) cHF+F+ROSI; (iv) cHF+PIO, cHF with 50 mg pioglitazone/kg diet; and (v) cHF+F+PIO, or chow-fed. Plasma concentrations of 163 metabolites were evaluated using a targeted metabolomics approach. Both TZDs preserved glucose homeostasis and normal plasma lipid levels while inducing adiponectin, with pioglitazone showing better effectiveness. The beneficial effects of TZDs were further augmented by the combination treatments. cHF+F+ROSI but not cHF+F+PIO counteracted development of obesity, in correlation with inducibility of fatty acid β-oxidation, as revealed by the metabolomic analysis. By contrast, only cHF+F+PIO eliminated hepatic steatosis and this treatment also reversed insulin resistance in dietary obese mice. Our results reveal differential effects of rosiglitazone and pioglitazone, unmasked in the combination treatment with n-3 LC-PUFA, and support the notion that n-3 LC-PUFA could be used as add-on treatment to TZDs in order to improve diabetic patient's therapy.