Cholesterol reduction in cardiovascular disease. Clinical benefits and possible mechanisms

Edible bird's nest attenuates procoagulation effects of high-fat diet in rats

Edible bird’s nest (EBN) is popular in Asia, and has long been used traditionally as a supplement. There are, however, limited evidence-based studies on its efficacy. EBN has been reported to improve dyslipidemia, which is closely linked to hypercoagulation states. In the present study, the effects of EBN on high-fat diet- (HFD-) induced coagulation in rats were evaluated. Rats were fed for 12 weeks with HFD alone or in combination with simvastatin or EBN. Food intake was estimated, and weight measurements were made during the experimental period. After sacrifice, serum oxidized low-density lipoprotein (oxLDL), adiponectin, leptin, von willibrand factor, prostacyclin, thromboxane and lipid profile, and whole blood coagulation indices (bleeding time, prothrombin time, activated partial thromboplastin time, red blood count count, and platelet count) were estimated. Furthermore, hepatic expression of coagulation-related genes was evaluated using multiplex polymerase chain reaction. The results indicated that EBN could attenuate HFD-induced hypercholesterolemia and coagulation similar to simvastatin, partly through transcriptional regulation of coagulation-related genes. The results suggested that EBN has the potential for lowering the risk of cardiovascular disease-related hypercoagulation due to hypercholesterolemia.

Positive affect is not associated with incidence of cardiovascular disease: a population-based study of older persons

INTRODUCTION

The relationship between positive psychological well-being (PPWB) and cardiovascular disease (CVD) is inconsistent across different CVD outcomes and for different PPWB constructs, such as positive affect. In addition, the relationship between PPWB and CVD as a composite measure is rarely assessed.

OBJECTIVE

To assess whether positive affect is protective of incident CVD.

METHOD

Positive affect was assessed in two cohorts between 1993 and 2001 in Rotterdam using relevant questions from the Center for Epidemiological Studies Depression (CES-D) scale and the Hospital Anxiety and Depression Scale (HADS; in a sub-sample) in 6349 non-demented, CVD-free, consenting adults, aged 55+years. Composite CVD was defined as stroke, heart failure and coronary heart disease, which were continuously monitored through medical records until 1st April 2010.

RESULTS

There were 1480 (23.3%) first time CVD events during follow-up (11.9 ± 2.8 SD years, 58,416 person-years). Positive affect was not associated with incident CVD (CES-D HR: 1.00 per point, 95% CI: 0.98-1.02; HADS HR: 0.98, 95% CI: 0.92-1.05). Stratification by age or sex and assessment of separate CVD outcome did not change results.

CONCLUSION

In this large, population-based study, there was no association between positive affect and twelve-year incident CVD in older adults who were free of diagnosed CVD at baseline.

The role of the kidney and the sympathetic nervous system in hypertension

Nearly one-third of the world's population has hypertension. The human and societal impact of hypertension is enormous. Primary hypertension accounts for 95 % of cases of hypertension in adults. The pathogenesis of primary hypertension is complex. The kidney and the sympathetic nervous system play important roles in the development and maintenance of hypertension. This review discusses their respective roles, the interaction between the two, implications of sympathetic overactivity in kidney disease and therapeutic interventions that have been developed on the basis of this knowledge, especially modulation of the sympathetic nervous system.

Monascus purpureus-fermented Thai glutinous rice reduces blood and hepatic cholesterol and hepatic steatosis concentrations in diet-induced hypercholesterolemic rats

BACKGROUND

Red yeast rice (RYR) is a fermented product used as a food supplement to promote blood circulation and lower blood cholesterol levels in eastern Asia. Interestingly, monacolin K is the most active compound in RYR that proved to inhibit HMG-CoA reductase in the cholesterol biosynthesis pathway.

METHODS

The hypocholesterolemic effects of oral administration of Thai RYR, produced by fermentation of Thai glutinous rice (Oryza sativa L. var. Niaw San-pah-tawng) with Monascus purpureus CMU 002U, were determined in normal and hypercholesterolemic rats. The rats were divided into six groups, and fed two different kinds of diet. Groups I-II, normal rats fed with a normal diet (SP-diet), were treated with distilled water (SP-control) and 2.0 g/kg/day of RYR extract (SP-2 g). In Groups III-VI, the rats were rendered hypercholesterolemic by feeding them a high fat and cholesterol diet (HFC-diet), and were treated with distilled water (HFC-control), 1.0 g/kg/day (HFC-1 g), 2.0 g/kg/day (HFC-2 g) of RYR extract, and 5.0 mg/kg/day of rosuvastatin (HFC-rosuvastatin) for 30 days, respectively.

RESULTS

The RYR extract significantly decreased the concentrations of serum total cholesterol and low density lipoprotein cholesterol (LDL-C), atherosclerotic index, LDL-C/HDL-C ratio and hepatic cholesterol levels in both HFC-1 g and HFC-2 g groups (p < 0.05) as compared with the HFC-control group, and with no significant change in high density lipoprotein cholesterol (HDL-C) concentrations among all six groups. The reduction of serum TC and LDL-C also paralleled the observed changes in mRNA expressions of the genes involved in cholesterol biosynthesis and homeostasis in the liver. The hypercholesterolemic rats treated with RYR extract were significantly higher in LDLR and HMGR expression, but lower in CYP7A1 expression when compared to the untreated hypercholesterolemic rats (HFC-control) (p < 0.05). The hepatic injuries in hypercholesterolemic rats were also obviously alleviated by RYR extract.

CONCLUSIONS

The extract of Thai RYR possessed potent hypocholesterolemic and anti-atherogenic activities in diet-induced hypercholesterolemic rats. The possible mechanism involving cholesterol-lowering potential of the extract might contribute to its ability to increase LDL-C endocytosis in hepatocyte and to competitively inhibit HMG-CoA reductase, a key enzyme for cholesterol biosynthesis in liver.

Variable effects of gender and Western diet on lipid and glucose homeostasis in aged PCSK9-deficient C57BL/6 mice CSK9PC57BL/6

BACKGROUND

Proprotein convertase subtilisin/kexin-type 9 (PCSK9) downregulates clearance of plasma cholesterol by liver. Its inactivation increases this clearance, reducing cardiovascular risk. However, a lack of PCSK9 could also lead to cholesterol accumulation in pancreatic islet beta cells, impairing insulin secretion. We reported earlier that 4-month-old male PCSK9-deficient (KO) C57BL/6 mice were hyperglycemic and insulin-insufficient relative to their wild-type (WT) counterparts. Here, we examined how gender and diet affect lipid and glucose homeostasis in these mice at 8 months of age.

METHODS

After being fed a normal diet or a Western diet for over 6 months, KO mice were compared with same-gender WT mice for fasting plasma levels of total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), glucose, and insulin; for glucose disposal and glucose-stimulated insulin secretion (GSIS); and for pancreatic islet morphology.

RESULTS

A. Females: On normal diet, KO mice showed lower plasma TC, HDL-C, and LDL-C, higher plasma glucose, and normal glucose disposal despite impaired GSIS. On Western diet, they showed comparable plasma TC and HDL-C, but lower LDL-C, higher plasma glucose, and normal glucose disposal despite impaired GSIS. B. Males: On normal and Western diets, KO mice showed lower plasma TC, HDL-C, and LDL-C, similarly elevated plasma glucose, glucose intolerance, and impaired GSIS. C. Both: KO mice on either diet showed pancreatic islet dysmorphism, with larger, possibly immature secretory granules.

CONCLUSIONS

Lower LDL-C and impaired GSIS are two major phenotypes in aged PCSK9-deficient C57BL/6 mice. These phenotypes are modulated by gender and diet.

Alteration of glucose lowering effect of glibenclamide on single and multiple treatments with fenofibrate in experimental rats and rabbit models

Objective:

Diabetes mellitus is a syndrome of multiple etiologies. Both type 1 and type 2 diabetes lead to multiple abnormalities of lipid and lipoprotein metabolism. The aim of this investigation was to study the influence of fenofibrate on the blood glucose lowering effect of glibenclamide.

Materials and Methods:

Glibenclamide (0.45, 0.23 mg/kg) and fenofibrate (18.1, 9.38 mg/kg) was treated to normal, diabetic rats, and normal rabbits. Blood samples were collected at various time intervals and were analyzed for blood glucose levels using a glucometer.

Results:

Co-administration of fenofibrate with glibenclamide significantly elevated the blood glucose reduction exhibited by glibenclamide.

Conclusion:

The results obtained from single and multiple dose treatments clearly demonstrated the existence of drug-drug interaction at the dose tested in animal models. Hence, this investigation would serve as a preclinical evidence for the effect of fenofibrate on the therapeutic efficacy of glibenclamide.

Endothelial Dysfunction is Associated with Occult Coronary Artery Disease Detected by Positron Emission Tomography

OBJECTIVE

Silent myocardial ischemia is common in asymptomatic subjects without a prior history of coronary artery disease (CAD) and is associated with increased morbidity and mortality. Our objective was to determine whether endothelial dysfunction is associated with silent myocardial ischemia and whether the association is independent of genetic and familial factors.

MATERIAL AND METHODS

We examined 416 male monozygotic and dizygotic twins aged 47 to 63 years, free of symptomatic CAD. Subclinical ischemia was diagnosed by [13N] ammonia positron emission tomography at rest and after adenosine stress. Endothelial function was measured by flow-mediated dilation (FMD) of the brachial artery. Generalized estimating equations were used for analysis.

RESULTS

Fixed perfusion defects were found in 24 (6%) twins and reversible perfusion defects in 90 (22%) twins, indicating subclinical ischemia. There was an inverse correlation between FMD and the reversible perfusion defect score (r = - 0.14, p=0.01) but not the fixed defect score (r= -0.017, p=0.73). From the lowest to the highest quartile of FMD, the prevalence of reversible defects decreased 28% to 14%, p=0.008. In multivariable analysis, reversible defects were significantly associated with each quartile of decreasing FMD (OR =1.3; 95% 1.1, 2.5). In 54 twin pairs discordant for endothelial dysfunction (FMD ≤ 7% dilation from baseline), twins with endothelial dysfunction had 9% higher likelihood of having perfusion defects than their co-twins without endothelial dysfunction (p=0.041).

CONCLUSIONS

Endothelial dysfunction is independently associated with silent ischemia and this association is not confounded by genetic or other shared familial factors.

Thiazolidinedione-independent activation of peroxisome proliferator-activated receptor γ is a potential target for diabetic macrovascular complications

Macrovascular complications are responsible for the high morbidity and mortality in patients with diabetes. Peroxisome proliferator‐activated receptor γ (PPARγ) plays a central role in the process of adipocyte differentiation and insulin sensitization, and also possesses anti‐atherogenic effects. Recently, some statins, angiotensin II type 1 receptor blockers and calcium channel blockers have been reported to activate PPARγ. However, the impact of PPARγ activation on diabetic macrovascular complications is not fully understood. It has been reported that the activation of PPARγ by thiazolidinediones induces anti‐atherogenic effects in vascular cells, including monocytes/macrophages, endothelial cells and smooth muscle cells, in atherosclerotic animal models and in clinical studies. We have reported that hydroxymethylglutaryl coenzyme A reductase inhibitors (statins), which are used for treatment of hypercholesterolemia, activate PPARγ and mediate anti‐atherogenic effects through PPARγ activation in macrophages. Also, telmisartan, an angiotensin type I receptor blocker, has been reported to have anti‐atherogenic effects through PPARγ activation. Furthermore, we have reported that nifedipine, a dihydropyridine calcium channel blocker, can activate PPARγ, thereby mediating anti‐atherogenic effects in macrophages. Therefore, statin therapy and part of anti‐hypertensive therapy might produce beneficial effects through PPARγ activation in hypercholesterolemic and/or hypertensive patients with diabetes, and PPARγ might be a therapeutic target for diabetic macrovascular complications. In the present review, we focus on the anti‐atherogenic effects of PPARγ and suggest potential therapeutic approaches to prevent diabetic macrovascular complications. (J Diabetes Invest, doi: 10.1111/j.2040‐1124.2011.00182.x, 2012)

Association of body mass index and abdominal adiposity with atherogenic lipid profile in Nigerians with type 2 diabetes and/or hypertension

Background:

We explored the relationship between anthropometric indices (obesity and abdominal adiposity) and the presence of an atherogenic lipid profile in Nigerians with major cardiovascular risk factors (type 2 diabetes mellitus-T2DM, hypertension-HBP, and concomitant disease).

Materials and Methods:

Using a prospective design, 278 patients with T2DM, HBP, or concomitant disease, attending out-patient diabetes and hypertension clinics at a tertiary institution in Nigeria were evaluated. All patients were cholesterol-lowering oral medication naοve. Demographic and clinical data and anthropometric measurements were documented. Fasting lipid profiles were measured in all cases. The cut-off points for defining dyslipidaemia were: Elevated total cholesterol (TC) (mg/dL) ≥200, elevated low-density lipoprotein cholestrol (LDL-C) (mg/dL) ≥100, low high-density lipoprotein cholesterol (HDL-C) (mg/dL) <40 for men and <50 for women, and high triglycerides (TG) (mg/dL) ≥150 mg/dL.

Results:

We found a significantly higher mean BMI (kg/m²) in the HBP group (30.5 ± 6.0) compared to T2DM (28.1 ± 5.9) and concomitant HBP and T2DM groups (29.4 ± 5.2) (ANOVA; P = 0.02). The most frequent dyslipidaemia was elevated LDL-C in 92 (96.8%) HBP, 73 (85.9%) T2DM and 79 (80.6%) concomitant disease. The frequency of low HDL-C was highest in T2DM (68.2%) compared to the other 2 groups (P = 0.03).

Conclusions:

Only TG levels were found to relate with any anthropometric index (waist circumference (WC) in this case) in Nigerians with major cardiovascular risk factors in this study. Routine anthropometric indices do not appear to be reliable surrogates for atherogenicity measured by abnormalities in TC, LDL-C and HDL-C.

Colesevelam hydrochloride in the management of dyslipidemia

Dyslipidemia is a highly heterogeneous group of disorders strongly influenced by both genetic and environmental factors. Dyslipidemia significantly increases risk for atherosclerotic disease and all of its various clinical manifestations. Identifying patients with dyslipidemia and initiating therapies aimed at normalizing the lipid profile has been demonstrated to significantly reduce the risk for myocardial infarction, stroke and cardiovascular mortality in both the primary and secondary prevention settings. Guidelines in Europe, Canada and the USA emphasize the need to reduce the burden of atherogenic lipoproteins in serum and to raise levels of high-density lipoproteins in patients at risk for cardiovascular events. Statins have emerged as front-line therapy for managing dyslipidemia, especially in patients with elevated serum levels of low-density lipoprotein cholesterol. As guidelines emphasize the need to reduce serum low-density lipoprotein cholesterol to lower levels, goal attainment can be challenging. The use of combination therapy increases the likelihood of therapeutic success for many patients. Furthermore, a significant percentage of patients with dyslipidemia either cannot achieve goals on statin monotherapy, choose not to take a statin or do not tolerate these drugs due to adverse side effects, such as myalgias, weakness or hepatotoxicity. This article summarizes the pharmacology, clinical efficacy and safety of colesevelam hydrochloride, a bile acid-binding resin. Bile acid-binding resins are orally administered anion-exchange resins that are not absorbed systemically. These agents bind bile acids and reduce their reabsorption at the level of the terminal ileum and prevent their enterohepatic recirculation. Colesevelam has a favorable side effect and toxicity profile and significantly impacts serum levels of lipoproteins when used as monotherapy or when used in combination with either statins or ezetimibe.

Thin-film microfabricated nanofluidic arrays for size-selective protein fractionation

Size-selective fractionation and quantitation of biostructures in the sub-hundred nanometer size range is an important research area. Unfortunately, current methods for size fractionation are complex, time consuming, or offer poor resolution. Using standard microfabrication technology, we developed a nanofluidic sieving system to address these limitations. Our setup consists of an array of parallel nanochannels with a height step in each channel, an injection reservoir, and a waste reservoir. The height steps can size fractionate a protein mixture as a solution flows through the nanochannels via capillary action. We tested this system with different sizes and concentrations of five proteins to understand protein size and height step effects on trapping. Our results clearly show size-dependent trapping of proteins at nanometer-scale height steps in nanochannels. We also developed a model that predicts the observed size-dependent trapping of proteins. This work is a key step towards scalable nanofluidic methods for molecular fractionation.

Dyslipidemia in rat fed with high-fat diet is not associated with PCSK9-LDL-receptor pathway but ageing

BACKGROUND

Obesity is associated with unfavorable alternations in plasma lipid profile and a broad spectrum of cardio-metabolic disorders. Proprotein convestase subtilisin kexin type 9 (PCSK9) is a novel circulating protein that promotes hypercholesterolemia by decreasing hepatic low lipoprotein density receptor (LDLR) protein. However, the relationship between PCSK9 concentration and lipid profile in an obesity condition has less been investigated.

OBJECTIVE

To examine the changes of plasma PCSK9 concentration in a rat model fed with high fat diet (HFD) and its correlation to lipid profile, body weight and ageing.

METHODS

Twenty male Sprague Dawley (SD) rats were divided into two groups, control group (fed with normal pellet for 4 weeks), and high-fat diet group (fed with 3% cholesterol enrich diet for 4 weeks). Blood samples of rats were obtained before and at days 14, 21, and 28 in both groups. The body weight, plasma metabolic parameters (glucose, lipid profile) and PCSK9 were determined at indicated time points.

RESULTS

The body weights were significantly increased in rats fed with HFD compared to that in rats with normal pellets at day 28. Additionally, total cholesterol (TC), triglyceride (TG), and low density lipoprotein cholesterol (LDL-C) levels in rat fed with HFD were also higher than that in rats fed with control diet while decreased high density lipoprotein cholesterol (HDL-C) levels were found in rats with HFD at day 28. More interesting, there were no differences of plasma PCSK9 concentrations as well as hepatic expression of LDLR between the two groups at day 28.

CONCLUSIONS

Although the body weight and LDL-C were significantly increased in rats fed with HFD at 4 weeks, there were no differences of changes in plasma PCSK9 concentration and LDLR expression of liver tissue in both groups at baseline and day 28, suggesting that dyslipidemia in the rat model with HFD appears not to be associated with PCSK9-LDLR pathway but ageing.

Evaluation of Mallotus oppositifolius Methanol Leaf Extract on the Glycaemia and Lipid Peroxidation in Alloxan-Induced Diabetic Rats: A Preliminary Study

Objective. Mallotus oppositifolius (Geiseler) Müll. Arg. (Euphorbiaceae) is folklorically used to “treat” diabetic conditions in some parts of Nigeria therefore the study, to investigate the extract of the leaves for activities on hyperglycaemia, lipid peroxidation, and increased cholesterol levels in vivo in alloxan diabetic rats as well as its potential antioxidant activity in vitro. Methods. Albino rats (240–280 g) were given an injection of 120 mg/kg body weight, i.p. of alloxan monohydrate. After 8 days, diabetic animals with elevated fasting blood glucose levels (>9 mmol/L) were considered and selected for the study. Results. Oral treatment with the extract administered every 12 h by gavage at doses of 100, 200, and 400 mg/kg of the extract to the test rats, for 14 days, resulted in a significant dose-dependent decrease in blood glucose levels from 12.82 ± 1.02 mmol/dL to 4.92 ± 2.01 mmol/dL at the highest dose of 400 mg/kg compared to the control drug and glibenclamide as well as attendant significant decline in diabetic rats employed in the study. Conclusion. The extract also showed in vitro concentration-dependent antioxidant activity following the 1,1-diphenyl-2-picryl-hydrazyl (DPPH) and ferric reducing assays. Findings further suggest the presence of active antidiabetic and antioxidant principles in M. oppositifolius leaves.

Rosuvastatin enhances angiogenesis via eNOS-dependent mobilization of endothelial progenitor cells

Circulating endothelial progenitor cells (circEPCs) of bone marrow (BM) origin contribute to postnatal neovascularization and represent a potential therapeutic target for ischemic disease. Statins are beneficial for ischemia disease and have been implicated to increase neovascularization via mechanisms independent of lipid lowering. However, the effect of Statins on EPC function is not completely understood. Here we sought to investigate the effects of Rosuvastatin (Ros) on EPC mobilization and EPC-mediated neovascularization during ischemic injury. In a mouse model of surgically-induced hindlimb ischemia (HLI), treatment of mice with low dose (0.1 mg/kg) but not high dose (5 mg/kg) significantly increased capillary density and accelerated blood flow recovery, as compared to saline-treated group. When HLI was induced in mice that had received Tie2/LacZ BM transplantation, Ros treatment led a significantly larger amount of endothelial cells (ECs) of BM origin incorporated at ischemic sites than saline. After treatment of mice with a single low dose of Ros, circEPCs significantly increased from 2 h, peaked at 4 h, declined until 8 h. In a growth-factor reduced Matrigel plug-in assay, Ros treatment for 5 d induced endothelial lineage differentiation in vivo. Interestingly, the enhanced circEPCs and post-HLI neovascularization stimulated by Ros were blunted in mice deficient in endothelial nitric oxide synthase (eNOS), and Ros increased p-Akt/p-eNOS levels in EPCs in vitro, indicating these effects of Ros are dependent on eNOS activity. We conclude that Ros increases circEPCs and promotes their de novo differentiation through eNOS pathway.

Statins modulate feedback regulation mechanisms between advanced glycation end-products and C-reactive protein: evidence in patients with acute myocardial infarction

OBJECTIVE

High sensitivity C-reactive protein (hsCRP) and advanced glycation end-products (AGEs) have been proposed as mediators in inflammation and atherosclerosis. Therefore, we studied the relation between AGE and hsCRP in patients with acute myocardial infarction (AMI).

METHODS

Patients with AMI diagnosis and satisfying our inclusion criteria were included during 2009-2011 in an unicentre registry of AMI patients for a cross-sectional study. The final cohort was composed of 156 patients (46.2% STEMI and 27.6% with type-2 diabetes). AGE and hsCRP were measured in plasma.

RESULTS

Diabetic patients were older than non-diabetics (68.6 ± 10.6 vs. 60.4 ± 13.9 years; p<0.05), presented more incidence of hypertension (62.8 vs. 36.3%; p<0.05) and were in a higher Killip class (p<0.05). The mean values of fluorescent AGE and hsCRP levels were 61.3 ± 49.8 AU and 2.4 ± 4.0 mg/L, respectively, and there were no differences in these parameters between diabetic and non-diabetic patients. A direct association between AGE and hsCRP levels was observed, mainly in diabetic patients (r=0.258; p=0.018). Importantly, this association disappeared in patients who had been treated with statins before their AMI (r=-0.055; p=0.845), but it was maintained in non-diabetic patients naïve for statins treatment (r=0.634; p<0.001), independently of other treatments and confounding parameters.

CONCLUSIONS

This is the first evidence in humans of a feedback regulation mechanism between CRP and the AGE-RAGE axis modulated by statins.

Long-term administration of rosuvastatin prevents contractile and electrical remodelling of diabetic rat heart

In recent years, many findings have been presented about the potential benefit of statin therapy on diabetes-induced cardiovascular complications. Cardioprotective effects of statins were suggested to be mediated at least in part through inhibition of small GTPases, particularly those of the Rho family. The present study was designed to examine whether rosuvastatin can improve electrical remodeling and contractile dysfunction in type 1 diabetic rat heart via modulation of RhoA pathway. Type 1 diabetes was induced by single dose injection of STZ (50 mg/kg). One week after injection rosuvastatin (10 mg/kg/day) and sham treatment was given for 5 weeks in the diabetic rats, as well as in control groups. Shortening and Ca²⁺ transients were recorded in myocytes loaded with Fura2-AM. Membrane currents and Ca²⁺ transients were measured synchronously via whole-cell patch clamping. In untreated diabetic rats, relaxation of shortening and decay of the matched Ca²⁺ transients were prolonged. Fractional shortening and Ca²⁺ transients were also decreased. Rosuvastatin treatment reversed those changes. I(CaL) density did not change in either group but rosuvastatin recovered the loss of sarcoplasmic reticulum Ca²⁺ and Na⁺/Ca²⁺ exchange as evidenced from amplitude and decay of caffeine-induced Ca²⁺ transients, peak INCX and calculated sarcoplasmic reticulum Ca²⁺ content. Diabetes-induced attenuation of I(to) and I(sus) was also reversed, whilst I(K1) was unchanged in diabetes and unaffected by treatment. Rosuvastatin prevented the diabetes-induced increase in RhoA expression. Plasma cholesterol and triglyceride levels were higher in diabetic rats, but rosuvastatin reduced only the latter. In conclusion, HMG-CoA reductase inhibitor rosuvastatin can prevent diabetes-induced electrical and functional remodeling of heart due to inhibition of RhoA signalling rather than reduction of cholesterol level.

Statins exert the pleiotropic effects through small GTP-binding protein dissociation stimulator upregulation with a resultant Rac1 degradation

OBJECTIVE

The pleiotropic effects of 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors (statins) independent of cholesterol-lowering effects are thought to be mediated through inhibition of the Rho/Rho-kinase pathway. However, we have previously demonstrated that the pleiotropic effects of regular-dose statins are mediated mainly through inhibition of the Rac1 signaling pathway rather than the Rho/Rho-kinase pathway, although the molecular mechanisms of the selective inhibition of the Rac1 signaling pathway by regular-dose statins remain to be elucidated. In this study, we tested our hypothesis that small GTP-binding protein GDP dissociation stimulator (SmgGDS) plays a crucial role in the molecular mechanisms of the Rac1 signaling pathway inhibition by statins in endothelial cells.

APPROACH AND RESULTS

In cultured human umbilical venous endothelial cells, statins concentration-dependently increased SmgGDS expression and decreased nuclear Rac1. Statins also enhanced SmgGDS expression in mouse aorta. In control mice, the protective effects of statins against angiotensin II-induced medial thickening of coronary arteries and fibrosis were noted, whereas in SmgGDS-deficient mice, the protective effects of statins were absent. When SmgGDS was knocked down by its small interfering RNA in human umbilical venous endothelial cells, statins were no longer able to induce Rac1 degradation or inhibit angiotensin II-induced production of reactive oxygen species. Finally, in normal healthy volunteers, statins significantly increased SmgGDS expression with a significant negative correlation between SmgGDS expression and oxidative stress markers, whereas no correlation was noted with total or low-density lipoprotein-cholesterol.

CONCLUSIONS

These results indicate that statins exert their pleiotropic effects through SmgGDS upregulation with a resultant Rac1 degradation and reduced oxidative stress in animals and humans.

Statins protect human endothelial cells from TNF-induced inflammation via ERK5 activation

3-Hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins) exert pleiotropic effects on the cardiovascular system, in part through a decrease in reactive oxygen species (ROS) formation and reduction of vascular inflammation. To elucidate the molecular mechanisms involved in these effects, we investigated the effect of statins on TNF-α-induced ROS production, vascular cell adhesion molecule-1 (VCAM-1) and intercellular adhesion molecule-1 (ICAM-1) expression in human aortic endothelial cells (HAECs). Exposure of HAECs to TNF-α caused production of ROS via Rac-1 membrane translocation and activation. The Rac-1 activation and ROS liberation mediated TNF-stimulated NF-κB activation and the subsequent VCAM-1 and ICAM-1 expression. Extracellular-signal-regulated kinase 5 (ERK5) plays a central role in inhibiting endothelial inflammation. Immune complex kinase assay of protein extracts from HAECs treated with atorvastatin revealed increased ERK5 activity in a time- and dose-dependent manner. In addition, pretreatment with atorvastatin inhibited TNF-α-induced ROS production and VCAM-1 and ICAM-1 expression. Chemical or genetic inhibition of ERK5 ablated the statins inhibition of Rac-1 activation, ROS formation, NF-κB, VCAM-1 and ICAM-1 expression induced by TNF-α. Taken together, statins, via ERK5 activation, suppress TNF-stimulated Rac-1 activation, ROS generation, NF-κB activation and VCAM-1 and ICAM-1 expression in human ECs, which provides a novel explanation for the pleiotropic effects of statins that benefit the cardiovascular system.

Hypolipidemic effect ofAlpinia galanga (Rasna) andKaempferia galanga (Kachoori)

The rhizome of bothAlpinia galanga andKaempferia galanga are widely used in the Ayurvedic system of medicine in the treatment of various inflammatory diseases, diabetes mellitus and obesity. Present study evaluated the hypolipidemic action of the ethanolic extract of these plantsin vivo. The oral administration of the extracts (20mg/day) of bothA. galanga andK. galanga effectively lowered the serum and tissue levels of total cholesterol, triglycerides, phospholipids and significantly increased the serum levels of high density lipoproteins(HDL) in high cholesterol fed white wistar rats over a period of 4 weeks. The results are indicative of these plants in various lipid disorders especially atherosclerosis.

Therapeutic role of toll-like receptor modification in cardiovascular dysfunction

Toll-like receptors (TLR) are key pattern recognition receptors in the innate immune system. The TLR-mediated immune response against pathogens is usually protective however inappropriate TLR activation may lead to excessive tissue damage. It is well recognised that TLRs respond to a variety of endogenous as well as exogenous ligands. By responding to endogenous ligands that are exposed during cellular damage, TLRs have been implicated in a range of pathological conditions associated with cardiovascular dysfunction. Increasing knowledge on the mechanisms involved in TLR signalling has encouraged the exploration of therapeutic pharmacological modulation of TLR activation in conditions such as atherosclerosis, ischaemic heart disease, heart failure and ischaemic reperfusion injury. The aim of this review is to explore the translational potentials of TLR modification in cardiovascular dysfunction, where these agents have been studied.

Atherosclerosis and physical activity

Atherosclerosis and coronary heart disease have been considered as major health problem worldwide. Abnormalities in lipids and lipoprotein metabolism and impairment of endothelial function have been implicated as the main contributing factors in atherosclerosis and its progression. Physical activity has been recognized as a preventive measure for atherosclerosis.

Comparison of the effects of 52 weeks weight loss with either a high-protein or high-carbohydrate diet on body composition and cardiometabolic risk factors in overweight and obese males

BACKGROUND

A high-protein (HP), low-fat weight-loss diet may be advantageous for improving cardiometabolic health outcomes and body composition. To date, only limited research has been conducted in male participants.

OBJECTIVE

To evaluate the medium to long-term effects of two, low-fat, hypocaloric diets differing in carbohydrate:protein ratio on body composition and cardiometabolic health outcomes in overweight and obese males.

DESIGN

One hundred and twenty males (age 50.8±9.3 (s.d.) years, body mass index 33.0±3.9 kg m(-2)) were randomly assigned and consumed a low-fat, isocaloric, energy-restricted diet (7 MJ per day) with either HP (protein:carbohydrate:fat %energy, 35:40:25) or high carbohydrate (HC; 17:58:25). Body weight, body composition and cardiometabolic risk factors were assessed at baseline and after 12 and 52 weeks.

RESULTS

Sixty-eight participants completed the study (HP, n=33; HC, n=35). At 1 year both the groups experienced similar reductions in body weight (HP, -12.3±8.0 kg (-12%); HC, -10.9±8.6 kg (-11%); P=0.83 time × group interaction) and fat mass (-9.9±6.0 kg (-27%) vs -7.3±5.8 kg (-22%); P=0.11). Participants who consumed the HP diet lost less fat-free mass (-2.6±3.7 kg (-4%) vs -3.8±4.7 kg (-6%); P<0.01). Both groups experienced similar increases in high-density lipoprotein cholesterol (8%) and reductions in total cholesterol (-7%), low-density lipoprotein cholesterol (-9%), triglycerides (-24%), glucose (-3%), insulin (-38%), blood pressure (-7/-12%) and C-reactive protein (-29%), (P0.14).

CONCLUSION

In overweight and obese men, both a HP and HC diet reduced body weight and improved cardiometabolic risk factors. Consumption of a HP diet was more effective for improving body composition compared with an HC diet.

Hemodynamic effects of peri-operative statin therapy in on-pump cardiac surgery patients

Background

Peri-operative statin therapy in cardiac surgery cases is reported to reduce the rate of mortality, stroke, postoperative atrial fibrillation, and systemic inflammation. Systemic inflammation could affect the hemodynamic parameters and stability. We set out to study the effect of statin therapy on perioperative hemodynamic parameters and its clinical outcome.

Methods

In a single center study from 2006 to 2007, peri-operative hemodynamic parameters of 478 patients, who underwent cardiac surgery with cardiopulmonary bypass, were measured. Patients were divided into those who received perioperative statin therapy (n = 276; statin group) and those who did not receive statin therapy (n = 202; no-statin group). The two groups were compared together using Kolmogorov-Smirnov-Test, Fisher’s-Exact-Test, and Student’s-T-test. A p value < 0.05 was considered as significant.

Results

There was no significant difference in the preoperative risk factors. Onset of postoperative atrial fibrillation was not affected by statin therapy. Extended hemodynamic measurements revealed no significant difference between the two groups, apart from Systemic Vascular Resistance Index (SVRI) . The no-statin group had a significantly higher SVRI (882 ± 206 vs. 1050 ± 501 dyn s/cm⁵/m², p = 0.022). Inotropic support was the same in both groups and no significant difference in the mortality rate was noticed. Also, hemodynamic parameters were not affected by different types and doses of statins.

Conclusions

Perioperative statin therapy for patients undergoing on-pump coronary bypass grafting or valvular surgery, does not affect the hemodynamic parameters and its clinical outcome.

Asymmetric dimethylarginine: a novel cardiovascular risk factor in end-stage renal disease

OBJECTIVE

This cross-sectional study explored the association between carotid intima-media thickness (CIMT) and the oxidative stress markers asymmetric dimethylarginine (ADMA) and homo cysteine in patients with end-stage renal disease who were on haemodialysis.

METHODS

A total of 30 patients undergoing chronic haemodialysis treatment were recruited to this study. Homocysteine and ADMA levels were determined using a fluorescence polarization immunoassay and an enzyme-linked immunosorbent assay, respectively. CIMT was measured as a marker of atherosclerosis using high-resolution ultrasonography and was performed after haemodialysis.

RESULTS

Significant positive correlations were found between CIMT and ADMA, and CIMT and duration of haemodialysis. Linear regression analysis showed that ADMA level and age were significant independent determinants of CIMT, whereas homo cysteine was not.

CONCLUSIONS

The relationship demonstrated between plasma ADMA and carotid artery thickening suggests that ADMA may be a novel marker of atherosclerosis in patients on haemodialysis.

Yoga training improves metabolic parameters in obese boys

Yoga has been known to have stimulatory or inhibitory effects on the metabolic parameters and to be uncomplicated therapy for obesity. The purpose of the present study was to test the effect of an 8-week of yoga-asana training on body composition, lipid profile, and insulin resistance (IR) in obese adolescent boys. Twenty volunteers with body mass index (BMI) greater than the 95th percentile were randomly assigned to yoga (age 14.7±0.5 years, n=10) and control groups (age 14.6±1.0 years, n=10). The yoga group performed exercises three times per week at 40~60% of heart-rate reserve (HRR) for 8 weeks. IR was determined with the homeostasis model assessment of insulin resistance (HOMA-IR). After yoga training, body weight, BMI, fat mass (FM), and body fat % (BF %) were significantly decreased, and fat-free mass and basal metabolic rate were significantly increased than baseline values. FM and BF % were significantly improved in the yoga group compared with the control group (p<0.05). Total cholesterol (TC) was significantly decreased in the yoga group (p<0.01). HDL-cholesterol was decreased in both groups (p<0.05). No significant changes were observed between or within groups for triglycerides, LDL-cholesterol, glucose, insulin, and HOMA-IR. Our findings show that an 8-week of yoga training improves body composition and TC levels in obese adolescent boys, suggesting that yoga training may be effective in controlling some metabolic syndrome factors in obese adolescent boys.

Diabetes-specific nutrition algorithm: a transcultural program to optimize diabetes and prediabetes care

Type 2 diabetes (T2D) and prediabetes have a major global impact through high disease prevalence, significant downstream pathophysiologic effects, and enormous financial liabilities. To mitigate this disease burden, interventions of proven effectiveness must be used. Evidence shows that nutrition therapy improves glycemic control and reduces the risks of diabetes and its complications. Accordingly, diabetes-specific nutrition therapy should be incorporated into comprehensive patient management programs. Evidence-based recommendations for healthy lifestyles that include healthy eating can be found in clinical practice guidelines (CPGs) from professional medical organizations. To enable broad implementation of these guidelines, recommendations must be reconstructed to account for cultural differences in lifestyle, food availability, and genetic factors. To begin, published CPGs and relevant medical literature were reviewed and evidence ratings applied according to established protocols for guidelines. From this information, an algorithm for the nutritional management of people with T2D and prediabetes was created. Subsequently, algorithm nodes were populated with transcultural attributes to guide decisions. The resultant transcultural diabetes-specific nutrition algorithm (tDNA) was simplified and optimized for global implementation and validation according to current standards for CPG development and cultural adaptation. Thus, the tDNA is a tool to facilitate the delivery of nutrition therapy to patients with T2D and prediabetes in a variety of cultures and geographic locations. It is anticipated that this novel approach can reduce the burden of diabetes, improve quality of life, and save lives. The specific Southeast Asian and Asian Indian tDNA versions can be found in companion articles in this issue of Current Diabetes Reports.

Anti-diabetic activities of the methanol leaf extracts of Hymenocardia acida (tul.) in alloxan-induced diabetic rats

The effect of methanolic extract of Hymenocardia acida leaves on diabetes and associated lipidemia were investigated on experimentally-induced diabetic rats. The extract did not demonstrate any acutely toxic effect in rats within the dose range (250 mg/kg - 2000 mg/kg) employed in the study; hence it was well tolerated by the rats. In all experiments, the anti-diabetic effects were dose-dependent and comparable to that of glibenclamide (2 mg/kg) standard. At a dose of 500 mg/kg, lipid profile markers such as the serum total cholesterol (TC) levels, LDL-C, triglycerides and HDL-C were significantly lower (p <0.05) than those of both the treated and untreated controls.

Lack of a relationship between plasma PCSK9 concentrations and hepatic lipoprotein kinetics in obese people

Obesity is associated with unfavorable alterations in plasma lipid concentrations. Data obtained from studies in cultured cells and rodent models show that Protein Convertase Subtilisn/Kexin 9 (PCSK9), a secreted protein that leads to degradation of LDL receptors in the liver, is an important regulator of plasma LDL cholesterol concentrations. Recent evidence suggests that PCSK9 may also regulate the very low density lipoprotein (VLDL) receptor expression and VLDL-triglyceride (TG) metabolism. The purpose of this study was to determine whether circulating PCSK9 concentrations are correlated with VLDL-triglyceride kinetics in obese people. Plasma PCSK9 concentration and VLDL-TG kinetics were evaluated in 39 nondiabetic, obese subjects (body mass index 36.9 ± 4.3 kg/m(2)). Body composition was assessed by using dual-energy x-ray absorptiometry, and VLDL-TG kinetics were assessed by using stable isotopically labeled tracer infusion. We found that plasma PCSK9 concentrations correlated significantly with percent body fat (r = 0.322, P = 0.046) and serum LDL-cholesterol concentrations (r = 0.333, P = 0.036), but not with VLDL-TG secretion rate (r = 0.083, P = 0.614) or clearance rate (r = 0.032, P = 0.845). These data suggest that PCSK9 is likely involved in LDL-cholesterol metabolism, but it is not a clinically important regulator of VLDL kinetics in obese individuals.

Amlamax in the management of dyslipidemia in humans

Hypercholesterolemia is the major cause of cardiovascular diseases leading to myocardial infarctions leading to considerable morbidity and mortality. During the past decade a group of molecules referred to as statins such as simvastatin, atrovastatin have been tried with great success in reducing total cholesterol. These molecules act by inhibiting the HMG CoA reductase enzyme thereby interfering with the synthesis of cholesterol. But statins reduce all the cholesterol including HDL cholesterol. Long term drug vigilance activity has revealed serious side effects of tendinopathy and related musculoskeletal disorders in some of the subjects. In an effort to manage hypercholesterolemia without serious side effects in a natural way we had tried the use of Amlamax a reconstituted, purified, standardized dried extract of amla (Emblica officinalis) containing 30% ellagitannins with other hydrolysable tannins on humans. We report the hitherto unobserved significant elevation of HDL cholesterol by the administration of Amlamax.

A new TCM formula FTZ lowers serum cholesterol by regulating HMG-CoA reductase and CYP7A1 in hyperlipidemic rats

ETHNOPHARMACOLOGICAL RELEVANCE

Based on a theory of Chinese Medicine, Regulating Gan (liver) to lower lipids that is in brief to regulate the lipid metabolic related factors in the liver will improve serum lipid profile, we have developed Fufang Zhenzhu Tiao Zhi (FTZ) which includes eight herbs that are quality assured. FTZ has been developed with the potential to correct abnormal lipid metabolism. This Chinese herbal medicine has been prescribed for 20 years, which has been issued patent and clinically proven for use in the treatment of dyslipidemia.

AIM OF THE STUDY

To investigate the cholesterol-lowering effect and the mode of action of FTZ extract on high lipid diet induced hyperlipidemic rats.

MATERIALS AND METHODS

The FTZ was prepared by alcohol and water extraction of eight herbs that have been quality-controlled according to the protocol. The cholesterol-lowering effect of FTZ was evaluated on SD rats fed with high-lipid diet. RT-PCR and western blot were used to analyze the gene expression of cholesterol metabolism-related enzymes including HMG-CoA reductase and cholesterol 7α-hydroxylase (CYP7A1) in the livers of the rats. The activity of HMG-CoA reductase and CYP7A1 were assessed by colorimetrical method and by quantification of the cholesterol metabolite of CYP7A1 using HPLC analysis respectively.

RESULTS AND CONCLUSIONS

FTZ significantly decreased the levels of serum total cholesterol (TC), triglycerides (TG) and low-density lipoprotein cholesterol (LDL-C), whilst elevated the serum high-density lipoprotein cholesterol (HDL-C) and decreased serum atherogenic index (A.I.) values in high lipid diet induced hyperlipidemic rats. Furthermore, FTZ showed significant antihyperlipidemic effect by at least three pathways in the high lipid diet induced hyperlipidemic rats: (1) upregulating the gene expression and activity of CYP7A1 which promotes the conversion of cholesterol into bile acid; (2) downregulating the gene expression and activity of HMG-CoA reductase to reduce de novo synthesis of cholesterol; (3) increasing the cholesterol excretion from feces. In these three pathways, HMG-CoA reductase and CYP7A1 are two pivotal enzymes in lipid cholesterol metabolism and are expressed mainly in hepatic cells, which support our new TCM treatment strategy: Modulating Liver to Treat Hyperlipemia.

Statin effect on thrombin inhibitor effectiveness during percutaneous coronary intervention: a post-hoc analysis from the ISAR-REACT 3 trial

OBJECTIVE

To determine whether statin therapy influences the efficacy of thrombin inhibitor bivalirudin or unfractionated heparin (UFH) during PCI.

SETTING AND PATIENTS

The post-hoc analysis of the ISAR-REACT 3 Trial included 4,570 patients: 3,106 patients were on statin therapy and 1,464 patients were not on statin therapy at the time of PCI procedure.

MAIN OUTCOME MEASURES

The primary outcome of this analysis was the 30-day composite of death, myocardial infarction, target vessel revascularization (TVR) or major bleeding.

RESULTS

The primary outcome occurred in 7.9% patients (n = 246) in the statin group versus 9.8% (n = 143) in the non-statin group (P = 0.036). There was an interaction in univariate (P = 0.028) and multivariable (P = 0.026) analysis between pre-PCI statin therapy and the type of antithrombotic therapy regarding myocardial infarction. In the statin group, bivalirudin significantly reduced the incidence of major bleeding (2.6 vs. 4.3%, P = 0.013) with no significant difference in the incidence of myocardial infarction (4.9 vs. 5.2%; P = 0.73) compared with UFH. In the non-statin group, bivalirudin was inferior to UFH regarding the incidence of myocardial infarction (7.1 vs. 4.1%, P = 0.013), yet major bleeding remained lower among bivalirudin-treated patients (4.0 vs. 5.2%, P = 0.25).

CONCLUSION

This post-hoc analysis suggests the existence of an interaction between statin therapy before PCI and antithrombotic therapy during PCI. Patients receiving bivalirudin therapy at the time of PCI showed less periprocedural myocardial infarction when on pre-PCI statin therapy which has to be investigated in further studies.

Hypocholesterolaemic effect of dietary inclusion of two putative probiotic bile salt hydrolase-producing Lactobacillus plantarum strains in Sprague-Dawley rats

The purpose of the present study was to evaluate the anti-hypercholesterolaemic effects of two putative probiotic bile salt hydrolase (Bsh)-producing Lactobacillus plantarum strains, i.e. Lp91 and Lp21, in rats. L. plantarum Lp91 exhibited excellent tolerance to low pH and high bile salt concentrations as well as showed potential Bsh activity, cholesterol assimilation and cholesterol co-precipitation ability along with L. plantarum Lp21 and NCDO82 strains. Furthermore, the potential effect of L. plantarum Lp91 on plasma cholesterol level was evaluated in Sprague-Dawley rats. Five treatment groups of rats (n 6) were fed experimental diets: normal diet, hypercholesterolaemic diet (HD), HD plus L. plantarum Lp91 (HD91) at ≥ 1·0 × 108 colony-forming units (cfu)/g, HD plus microencapsulated L. plantarum Lp91 (HDCap91) at ≥ 1·0 × 108 cfu/g and HD plus L. plantarum Lp21 (HD21) at ≥ 1·0 × 108 cfu/g for 3 weeks. Feed intake and feed efficiency differed significantly among the five groups. After 21 d of dietary treatment, comparative analysis revealed 23·26, 15·71 and 15·01 % reduction in total cholesterol, 21·09, 18·77 and 18·17 % reduction in TAG, 38·13, 23·22 and 21·42 % reduction in LDL-cholesterol, and the corresponding HDL-cholesterol values increased at the rate of 18·94, 10·30 and 7·78 % in treated groups HD91, HDCap91 and HD21, respectively. Faecal excretion of cholic acid and faecal lactobacilli counts were significantly higher in the probiotic treatment groups than in the control groups. In conclusion, these results suggest that the indigenous L. plantarum Lp91 strain has the potential to be explored as a probiotic in the management of hypercholesterolaemia.

Short-term exercise training prevents micro- and macrovascular disease following coronary stenting

The purpose of this study was to determine the effects of exercise on coronary blood flow and macrovascular atherosclerosis in response to stent deployment. Male Yucatan swine were placed on a control diet (C); on a high-fat/cholesterol diet (hypercholesterolemic; H); or on a high-fat/cholesterol diet and aerobically exercise trained (HX) starting after 36 wk on the diet. All pigs underwent coronary angiography and intravascular ultrasound (IVUS) guided placement of a bare metal stent in the circumflex coronary artery after 40 wk on diets and 3 wk later pigs underwent repeat angiography and IVUS and coronary blood flow (CBF) measurement. Average peak velocity (APV) was measured under basal conditions and in response to intracoronary application of the endothelium-independent vasodilator adenosine and the endothelium-dependent vasodilator bradykinin. There was a similar approximately 8-fold increase in total cholesterol in H and HX compared with control. Baseline CBF was increased above control and H in HX (P<0.05). At all doses adenosine-induced CBF was impaired in H, but preserved in HX. Similarly, bradykinin-induced CBF was impaired in H vs. control, yet was potentiated in HX. Microvessel density was decreased in H and preserved in HX vs. control. Native atheroma in HX was lower relative to H and control, while in-stent stenosis in HX was not different from H. Hyperlipidemia-induced microvascular dysfunction after stent deployment may be a result of reduction in microvessel density. This is the first report that short-term exercise training near the time of stenting prevents stent-induced microvascular dysfunction and attenuates native atheroma independent of changes in plasma cholesterol in this porcine model.

Does endothelial dysfunction contribute to the clinical status of patients with peripheral arterial disease?

Peripheral arterial disease leads to lower extremity ischemia and limb loss, and is linked to cardiovascular events. The anatomical extent of lower extremity atherosclerosis fails to fully explain ischemic symptoms or predict the development of critical limb ischemia. Endothelial dysfunction is known to contributed to the pathogenesis and clinical expression of coronary artery disease, but the importance of endothelial dysfunction in peripheral arterial disease remains incompletely understood. Endothelial dysfunction could contribute to lower extremity ischemia by impairing blood flow responses to ischemia, collateral formation and arterial remodelling, and by promoting vasospasm, thrombosis, plaque rupture and lesion progression. There is a need for additional studies examining the contribution of endothelial dysfunction to the pathogenesis of peripheral arterial disease, and the potential role of endothelial dysfunction as a surrogate marker with utility in the management of patients.

Fenofibrate Reduces Age-related Hypercholesterolemia in Normal Rats on a Standard Diet

Plasma cholesterol is increased in normal aging in both rodents and humans. This is associated with reduced elimination of cholesterol and decreased receptor-mediated clearance of plasma low-density lipoprotein (LDL) cholesterol. The aims of this study were: (1) to determine age-related changes in plasma lipid profiles, and (2) to determine the effect of fenofibrate, an activator of peroxisome proliferator activated receptor alpha (PPAR alpha), on plasma lipid profiles in normal rats on a standard diet. Male Sprague-Dawley (SD) rats (n=15) were fed standard chow and water from 10 to 25 weeks of age. During that period, we measured daily food intake, body weight, fasting and random blood glucose levels, plasma total cholesterol (TC), triglycerides (TG), and free fatty acid (FFA) levels. At 20 weeks of age, all rats were randomly divided into two groups: a fenofibrate group (in which rats were gavaged with 300 mg/kg/day of fenofibrate) and a control group (gavaged with water). Fenofibrate treatment lasted 5 weeks. There were no significant changes in daily food intake, blood glucose, and plasma TG level with age. Body weight, plasma TC, and FFA levels were significantly increased with age. Fenofibrate significantly decreased plasma concentrations of TC and FFA, which had been increased with age. However, fenofibrate did not influence the plasma concentration of TG, which had not increased with age. These results suggest that fenofibrate might have a novel role in preventing age-related hypercholesterolemia in SD rats on a normal diet.

Double impact on p-glycoprotein by statins enhances doxorubicin cytotoxicity in human neuroblastoma cells

The development of multidrug resistance (MDR) is a major problem during cancer treatment. Drug efflux via ATP-binding cassette (ABC) transporters is the main mechanism responsible for resistance to chemotherapeutics. We have recently observed that statins enhance susceptibility to doxorubicin-induced apoptosis in human rhabdomyosarcoma cells, which is now also observed in human SH-SY5Y neuroblastoma cells. We have therefore investigated the ABC transporter activity to confirm a possible inhibition by statins in SH-SY5Y cells. Indeed, simvastatin directly inhibited dye transport at equimolar concentrations of the ABC transporter inhibitor, verapamil. Making use of the fluorescence behavior of doxorubicin the accumulation of anthracycline was monitored in real-time confocal microscopy. The intracellular doxorubicin accumulation was immediately enhanced by statins in SH-SY5Y cells and also in a MYCN-amplified neuroblastoma cell line STA-NB-10. The heavily glycosylated P-glycoprotein (ABCB1, P-gp) transporter appeared as a 180-and 140-kDa species. Atorvastatin and simvastatin reduced the 180-kDa form of P-gp, but not verapamil. Thereby the fully glycosylated species is shifted to the core glycosylated species (140 kDa), which was only seen at statin exposure times longer than 24 hr. The functional importance of glycosylation of the transporter was highlighted by exogenous application of N-glycosidase F, which was sufficient to enhance doxorubicin accumulation. Hence, these novel findings of statins' dual impact on P-gp have clinical implications. The enhanced intracellular accumulation of chemotherapeutics or other ABC transporter substrates in the presence of statins may represent a novel concept to overcome MDR in cancer therapy and improve drug safety.

Influence of soy lecithin administration on hypercholesterolemia

Recent studies suggest that lecithin-rich diet can modify cholesterol homeostasis and hepatic lipoprotein metabolism. Considering the phytotherapeutic impact of lecithin, this work hypothesizes that lecithin administration in hypercholesterolemic patients may reduce cholesterol concentrations by increasing biliary secretion. Total cholesterol and LDL were evaluated after soy lecithin administration in hypercholesterolemic patients. One soy lecithin capsule (500 mg/RP-Sherer) was administrated daily. One-two months before the treatment beginning, blood samples were collected for total lipids and cholesterol fractions analysis. The results showed a reduction of 40.66% and 42.00% in total cholesterol and of 42.05% and 56.15% in LDL cholesterol after treatment for one and two months, respectively. A significant reduction in total cholesterol and LDL-cholesterol concentrations was observed during the first month of treatment, suggesting that the administration of soy lecithin daily may be used as a supplemental treatment in hypercholesterolemia.

Stimulation of autophagy by antilipolytic drugs may rescue rodents from age-associated hypercholesterolemia

Aging is characterized by several metabolic changes responsible for the decline of certain functions and the appearance of age-related diseases, including hypercholesterolemia, which is the main risk factor for atherosclerosis and cardiovascular disease. Similar changes in a number of morphological and biochemical parameters were observed in rats. Caloric restriction (CR) was shown to increase longevity and prevent age-related diseases in various organisms, and to counteract the age-associated increase in plasma cholesterol. CR was thought to operate through the stimulation of the process of macroautophagy. The aim of this work was to investigate the effect of the stimulation of macroautophagy on age-associated cholesterolemia. Mature Sprague-Dawley rats were fasted overnight and given the antilipolytic agent 3,5-dimethylpyrazole (DMP; 12 mg/kg b.w. in 0.2 mL of saline, intraperitoneally). The age-related changes in cholesterol plasma level, 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMG-CoA-R) activity, and lipoperoxidation were determined. Low-density lipoprotein (LDL) receptor expression was determined by immunoblot of sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE)-separated liver membranes. Results show that the stimulation of macroautophagy reduces the total LDL and high-density lipoprotein (HDL) cholesterol plasma level to juvenile values, and triglycerides levels even lower. The hypocholesterolemic action of DMP requires neither the counteraction of the age-related changes in the HMG-CoA-R activation state and regulation, nor the counteraction of the age-related increase in lipoperoxidation, and only involves a restoration of the numbers of LDL receptors on liver membranes to juvenile levels.

Antihyperlipidaemic activity of swertiamarin, a secoiridoid glycoside in poloxamer-407-induced hyperlipidaemic rats

We have investigated antihyperlipidaemic effect of swertiamarin (50 mg/kg, oral once) isolated from the perennial herb Enicostemma littorale Blume in poloxamer 407 (P-407)-induced hyperlipidaemic rats. Rats were made hyperlipidaemic by intraperitoneal administration of P-407 (400 mg/kg). Serum lipid levels such as total cholesterol, triglycerides and low-density lipoprotein cholesterol increased significantly (P < 0.001) compared with normal control rats. All these changes were significantly prevented in the rats treated with swertiamarin. Serum high-density lipoprotein (HDL) cholesterol was found to be reduced in the P-407 control rats. However, administration of swertiamarin significantly (P < 0.01) increased HDL levels and it showed a significant lipid-lowering effect, as well as a high antiatherogenic potential. Overall swertiamarin is an effective lipid-lowering lead compound and can be useful for preventing atherosclerosis.