Effect of atorvastatin (10 mg/day) on glucose metabolism in patients with the metabolic syndrome

Effects of statin therapy on glycemic control and insulin resistance: A systematic review and meta-analysis

AIMS

To update the evidence about the diabetogenic effect of statins.

METHODS

We searched for randomized-controlled trials reporting the effects of statin therapy on glycosylated hemoglobin (HbA1c) and/or homeostatic model insulin resistance (i.e., HOMA-IR) as indexes of diabetes. Studies were classified between the ones testing normal vs individuals with already altered glycemic control (HbA1c ≥ 6.5%; and HOMA-IR ≥ 2.15). Furthermore, studies were separated by statin type and dosage prescribed. Data are presented as mean difference (MD) and 95% confidence intervals.

RESULTS

A total of 67 studies were included in the analysis (>25,000 individuals). In individuals with altered glycemic control, statins increased HbA1c levels (MD 0.21%, 95% CI 0.16-to-0.25) and HOMA-IR index (MD 0.31, 95% CI 0.24-to-0.38). In individuals with normal glycemic control, statin increased HbA1c (MD 1.33%, 95% CI 1.31-to-1.35) and HOMA-IR (MD 0.49, 95% CI 0.41-to-0.58) in comparison to the placebo groups. The dose or type of statins did not modulate the diabetogenic effect.

CONCLUSIONS

Statins, slightly but significantly raise indexes of diabetes in individuals with adequate or altered glycemic control. The diabetogenic effect does not seem to be influenced by the type or dosage of statin prescribed.

Chronic Statin Treatment Does Not Impair Exercise Lipolysis or Fat Oxidation in Exercise-Trained Individuals With Obesity and Dyslipidemia

OBJECTIVE

To determine whether statin medication in individuals with obesity, dyslipidemia, and metabolic syndrome affects their capacity to mobilize and oxidize fat during exercise.

METHODS

Twelve individuals with metabolic syndrome pedaled during 75 min at 54 ± 13% V˙O2max (5.7 ± 0.5 metabolic equivalents) while taking statins (STATs) or after 96-hr statin withdrawal (PLAC) in a randomized double-blind fashion.

RESULTS

At rest, PLAC increased low-density lipoprotein cholesterol (i.e., STAT 2.55 ± 0.96 vs. PLAC 3.16 ± 0.76 mmol/L; p = .004) and total cholesterol blood levels (i.e., STAT 4.39 ± 1.16 vs. PLAC 4.98 ± 0.97 mmol/L; p = .008). At rest, fat oxidation (0.99 ± 0.34 vs. 0.76 ± 0.37 μmol·kg-1·min-1 for STAT vs. PLAC; p = .068) and the rates of plasma appearance of glucose and glycerol (i.e., Ra glucose-glycerol) were not affected by PLAC. After 70 min of exercise, fat oxidation was similar between trials (2.94 ± 1.56 vs. 3.06 ± 1.94 μmol·kg-1·min-1, STA vs. PLAC; p = .875). PLAC did not alter the rates of disappearance of glucose in plasma during exercise (i.e., 23.9 ± 6.9 vs. 24.5 ± 8.2 μmol·kg-1·min-1 for STAT vs. PLAC; p = .611) or the rate of plasma appearance of glycerol (i.e., 8.5 ± 1.9 vs. 7.9 ± 1.8 μmol·kg-1·min-1 for STAT vs. PLAC; p = .262).

CONCLUSIONS

In patients with obesity, dyslipidemia, and metabolic syndrome, statins do not compromise their ability to mobilize and oxidize fat at rest or during prolonged, moderately intense exercise (i.e., equivalent to brisk walking). In these patients, the combination of statins and exercise could help to better manage their dyslipidemia.

The Impact of Age on Statin-Related Glycemia: A Propensity Score-Matched Cohort Study in Korea

The aim of this study was to investigate the influence of statin on glycemic control in different age groups. Patients admitted for suspected or confirmed coronary artery disease between January 2005 and December 2013 in Seoul, Korea were initially enrolled. After propensity score matching, 2654 patients (1:1 statin users and non-users) were selected out of total 5041 patients, including 1477 “young” patients (≤60 y) and 1177 elderly patients (>60 y). HbA1c was decreased by 0.04% (±0.86%) in statin non-users. On the contrary, a slight increment of 0.05% (±0.71%) was found in statin users (p < 0.001). The change patterns of HbA1c were constant in both young and elderly patient groups. Furthermore, elderly statin users demonstrated significantly worse glycemic control in serum insulin and homeostatic model assessment—insulin resistance (HOMA-IR) index. In elderly patients, statin users were found to have a 2.61 ± 8.34 μU/mL increment in serum insulin, whereas it was 2.35 ± 6.72 μU/mL for non-users (p = 0.012). Statin users had a 0.78 ± 3.28 increment in HOMA-IR, in contrast to the 0.67 ± 2.51 increment in statin non-users (p = 0.008). In conclusion, statin treatment was associated with adverse glycemic control in the elderly population.

Metabolic syndrome and its pharmacologic treatment are associated with the time to castration-resistant prostate cancer

BACKGROUND

Metabolic syndrome and its pharmacologic treatment can potentially influence the progression of prostate cancer in men receiving androgen deprivation therapy (ADT). We aimed to evaluate the association between metabolic syndrome and its pharmacologic treatment with time to castration-resistant prostate cancer (CRPC).

METHODS

We identified 409 men with metastatic castration-sensitive prostate cancer receiving first line ADT from 1996 to 2014 at our institution. Information concerning metabolic syndrome, statin use, aspirin use, and metformin use at initiation of ADT was collected from medical records. Time to CRPC was defined as the duration between initiating ADT and diagnosis of CRPC based on the Prostate Cancer Working Group 3 definition. Flexible parametric survival models were used to calculate hazard ratios (HR, and 95% confidence intervals, CI) of the association between metabolic conditions and time from ADT initiation to CRPC.

RESULTS

During a median follow-up of 59 months, 87% (N = 356) men progressed to CRPC. Median time to CRPC was 19 months. Fifty-six percent of men met the definition of metabolic syndrome. Controlling for demographic and prostate cancer-specific variables, metabolic syndrome was associated with shorter time to CRPC (HR 1.41, 95% CI 1.09-1.81). Importantly, in men with metabolic syndrome, statin use was associated with a slower progression to CRPC (HR 0.70, 95% CI 0.49-0.98).

CONCLUSIONS

Our study suggests that metabolic syndrome is a risk factor for earlier progression from castration-sensitive to castration-resistant prostate cancer and raises the possibility that treatment, such as statin use, may slow the time to progression.

Laboratory data clustering in defining population cohorts: Case study on metabolic indicators

The knowledge on the general population health is important for creating public policies and organization of medical services. However, personal data are often limited, and mathematical models are employed to achieve a general overview. Cluster analysis was used in this study to assess general trends in population health based on laboratory data. Metabolic indicators were chosen to test the model and define population cohorts. Data on blood analysis of 33,049 persons, namely the concentrations of glucose, total cholesterol, and triglycerides, were collected in a public health laboratory and used to define metabolic cohorts employing computational data clustering (CLARA method). The population was shown to be distributed in 3 clusters: persons with hypercholesterolemia with or without changes in the concentration of triglycerides or glucose, persons with reference or close to reference concentrations of all three analytes and persons with predominantly elevated all three parameters. Clustering of biochemical data, thus, is a useful statistical tool in defining population groups in respect to certain health aspect.

Atorvastatin Attenuates Vascular Remodeling in Mice with Metabolic Syndrome

Fundamento

A síndrome metabólica é caracterizada por um conjunto de comorbidades. Durante a síndrome, observam-se alterações estruturais no sistema cardiovascular, especialmente o remodelamento vascular. Uma das causas predisponentes para essas alterações é a inflamação crônica oriunda de mudanças na estrutura e composição do tecido adiposo perivascular. Atorvastatina é eficaz no tratamento das dislipidemias. No entanto, seus efeitos pleiotrópicos não são totalmente compreendidos. Supõe-se que, durante a síndrome metabólica, ocorre remodelamento vascular e que o tratamento com atorvastatina pode ser capaz de atenuar tal condição.

Objetivos

Avaliar os efeitos do tratamento com atorvastatina sobre o remodelamento vascular em modelo experimental de síndrome metabólica.

Métodos

Camundongos Swiss receberam dieta controle ou dieta hiperglicídica por 18 semanas. Após 14 semanas de dieta, os camundongos foram tratados com veículo ou atorvastatina (20mg/kg) durante 4 semanas. Foram avaliados o perfil nutricional e metabólico por testes bioquímicos; análise estrutural da artéria aorta por histologia e dosagem de citocinas por ensaio imunoenzimático. O nível de significância aceitável para os resultados foi p <0,05.

Resultados

A dieta hiperglicídica promoveu o desenvolvimento de síndrome metabólica. Tal fato culminou no remodelamento hipertrófico do músculo liso vascular e tecido adiposo perivascular. Além disso, houve aumentos das citocinas TNF-α e IL-6 circulantes e no tecido adiposo perivascular. O tratamento com atorvastatina reduziu significativamente os danos metabólicos, o remodelamento vascular e os níveis de citocinas.

Conclusão

Atorvastatina ameniza danos metabólicos associados à síndrome metabólica induzida por dieta hiperglicídica, além de atenuar o remodelamento vascular, sendo esses efeitos associados à redução de citocinas pró-inflamatórias.

Effect of atorvastatin on testosterone levels

BACKGROUND

Statins are one of the most prescribed classes of drugs worldwide. Atorvastatin, the most prescribed statin, is currently used to treat conditions such as hypercholesterolaemia and dyslipidaemia. By reducing the level of cholesterol, which is the precursor of the steroidogenesis pathway, atorvastatin may cause a reduction in levels of testosterone and other androgens. Testosterone and other androgens play important roles in biological functions. A potential reduction in androgen levels, caused by atorvastatin might cause negative effects in most settings. In contrast, in the setting of polycystic ovary syndrome (PCOS), reducing excessive levels of androgens with atorvastatin could be beneficial.

OBJECTIVES

Primary objective To quantify the magnitude of the effect of atorvastatin on total testosterone in both males and females, compared to placebo or no treatment. Secondary objectives To quantify the magnitude of the effects of atorvastatin on free testosterone, sex hormone binding globin (SHBG), androstenedione, dehydroepiandrosterone sulphate (DHEAS) concentrations, free androgen index (FAI), and withdrawal due to adverse effects (WDAEs) in both males and females, compared to placebo or no treatment.

SEARCH METHODS

The Cochrane Hypertension Information Specialist searched the following databases for randomized controlled trials (RCTs) up to 9 November 2020: the Cochrane Hypertension Specialised Register; the Cochrane Central Register of Controlled Trials (CENTRAL); MEDLINE; Embase; ;two international trials registries, and the websites of the US Food and Drug Administration, the European Patent Office and the Pfizer pharmaceutical corporation. These searches had no language restrictions. We also contacted authors of relevant articles regarding further published and unpublished work.

SELECTION CRITERIA

RCTs of daily atorvastatin for at least three weeks, compared with placebo or no treatment, and assessing change in testosterone levels in males or females.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened the citations, extracted the data and assessed the risk of bias of the included studies. We used the mean difference (MD) with associated 95% confidence intervals (CI) to report the effect size of continuous outcomes,and the risk ratio (RR) to report effect sizes of the sole dichotomous outcome (WDAEs). We used a fixed-effect meta-analytic model to combine effect estimates across studies, and risk ratio to report effect size of the dichotomous outcomes. We used GRADE to assess the certainty of the evidence.

MAIN RESULTS

We included six RCTs involving 265 participants who completed the study and their data was reported. Participants in two of the studies were male with normal lipid profile or mild dyslipidaemia (N = 140); the mean age of participants was 68 years. Participants in four of the studies were female with PCOS (N = 125); the mean age of participants was 32 years. We found no significant difference in testosterone levels in males between atorvastatin and placebo, MD -0.20 nmol/L (95% CI -0.77 to 0.37). In females, atorvastatin may reduce total testosterone by -0.27 nmol/L (95% CI -0.50 to -0.04), FAI by -2.59 nmol/L (95% CI -3.62 to -1.57), androstenedione by -1.37 nmol/L (95% CI -2.26 to -0.49), and DHEAS by -0.63 μmol/l (95% CI -1.12 to -0.15). Furthermore, compared to placebo, atorvastatin increased SHBG concentrations in females by 3.11 nmol/L (95% CI 0.23 to 5.99). We identified no studies in healthy females (i.e. females with normal testosterone levels) or children (under age 18). Importantly, no study reported on free testosterone levels.

AUTHORS' CONCLUSIONS

We found no significant difference between atorvastatin and placebo on the levels of total testosterone in males. In females with PCOS, atorvastatin lowered the total testosterone, FAI, androstenedione, and DHEAS. The certainty of evidence ranged from low to very low for both comparisons. More RCTs studying the effect of atorvastatin on testosterone are needed.

Potential application of nanoemulsified garlic oil blend in mitigating the progression of type 2 diabetes-mediated nephropathy in Wistar rats

The renoprotective potential of nanoemulsified garlic oil blend (GNE) in alleviating the progressive stages of hyperlipidemia-mediated diabetic nephropathy was examined. The study was carried out in high fat-fed, streptozotocin-induced type 2 diabetic Wistar rats for five months. The diabetic rats showed a significant increase of area under the curve in OGTT (p < 0.01) and IPITT (p < 0.01), increased urinary albumin (p < 0.01), urinary microprotein (p < 0.001), total cholesterol (p < 0.01), triglycerides (p < 0.001) and LDL cholesterol (p < 0.001), with decreased serum albumin (p < 0.01), serum protein (p < 0.001) and HDL-cholesterol levels (p < 0.05) than the control rats. The histopathological analysis evidenced mesangial expansion and hypercellularity at the end of the first and third month, and glomerulosclerosis and tubular atrophy at the end of the fifth month in diabetic rats. Moreover, on disease progression, increase in urinary podocalyxin, NGAL and CD36 was observed, and the renal mRNA and protein expression of podocalyxin decreased significantly with a concomitant increase in NGAL and CD36 expression from first till fifth month end. The treatment with GNE (20 mg/kg) significantly ameliorated the serum albumin (p < 0.001) and urine albumin (p < 0.01) from the end of the third month with significant attenuation in the lipid profile than GO (20 mg/kg) or Ator (8 mg/kg). Moreover, GNE reverted the histopathological alterations and attenuated the aberrant mRNA, protein expression and urinary excretion level of renal CD36, podocalyxin and NGAL in diabetic rats from an early stage of disease till the end of the study period. This study demonstrated the enhanced efficacy of GO in nanoemulsified form in mitigating the progression of nephropathy in type 2 diabetic rats.

Comparison of the Efficacy and Safety of Rosuvastatin/Ezetimibe Combination Therapy and Rosuvastatin Monotherapy on Lipoprotein in Patients With Type 2 Diabetes: Multicenter Randomized Controlled Study

INTRODUCTION

Ezetimibe/statin combination therapy has been reported to provide additional cardioprotective effects compared to statin monotherapy. The apolipoprotein B/A1 (apoB/A1) ratio is an effective predictor of cardiovascular diseases. The aim of this study was to compare the efficacy and safety of rosuvastatin/ezetimibe combination therapy versus rosuvastatin monotherapy using the apoB/A1 ratio in patients with diabetes and hypercholesterolemia.

METHODS

In this randomized, multicenter, open-label, parallel-group study, patients were randomly assigned to receive the combination therapy of rosuvastatin 5 mg/ezetimibe 10 mg once daily (n = 68) or monotherapy with rosuvastatin 10 mg once daily (n = 68), for 8 weeks.

RESULTS

After the 8-week treatment, percentage change (least-square means ± standard error) in the apoB/A1 ratio in the rosuvastatin/ezetimibe group was significantly decreased compared to the rosuvastatin group (- 46.14 ± 1.58% vs.  - 41.30 ± 1.58%, respectively; P = 0.03). In addition, the proportion of patients achieving > 50% reduction in low-density lipoprotein-cholesterol (LDL-C) and in the comprehensive lipid target (LDL-C < 70 mg/dL, non-HDL-cholesterol [non-HDL-C] < 100 mg/dL, and apoB < 80 mg/dL) was significantly different between the two groups (76.5 and 73.5% in the rosuvastatin/ezetimibe group and 47.1 and 45.6% in the rosuvastatin group, respectively; P < 0.001). The reduction in total cholesterol, non-HDL-C, LDL-C, and apoB were greater in the rosuvastatin/ezetimibe group than in the rosuvastatin group. Both treatments were well tolerated, and no between-group differences in drug-related adverse events were observed.

CONCLUSION

The apoB/A1 ratio was significantly reduced in patients receiving combination therapy with ezetimibe and rosuvastatin compared to those receiving rosuvastatin monotherapy. Both treatments were well tolerated in patients with type 2 diabetes and hypercholesterolemia.

TRIAL REGISTRATION

NCT03446261.

Statins influence biomarkers of low grade inflammation in apparently healthy people or patients with chronic diseases: A systematic review and meta-analysis of randomized clinical trials

BACKGROUND

No earlier study summarized findings on the effect of statins on inflammatory biomarkers in apparently healthy individuals or those with chronic diseases. This study was done to systematically review earlier publications on the effect of statins on serum concentrations of C-reactive protein (CRP) and Interleukin-6 (IL-6) in apparently healthy individuals or those with chronic diseases.

METHODS

We searched relevant publications published up to December 2018 in PubMed, MEDLINE, SCOPUS, EMBASE, and Google Scholar databases. For this purpose, suitable MESH and non-MESH keywords were used. Randomized placebo-controlled clinical trials that examined the effect of statins on serum concentrations of CRP and IL-6 in apparently healthy adults or those with chronic diseases were included.

RESULTS

Overall, 18 studies with 23 effect sizes, that enrolled 32,156 individuals (38% female and 62% male; mean age: 44.79 years) were included. When we combined 21 effect sizes from 16 studies, we observed a significant reduction in circulating levels of CRP following administration of statins [Weighted Mean Difference (WMD): -0.80; 95% CI: -1.05, -0.56]. Combining 12 effect sizes from 11 studies, a significant reduction was found in serum CRP concentrations following administration of Atorvastatin (WMD: -0.57; 95% CI: -0.78, -0.35). Pooling 5 effect sizes from 2 studies, we found a significant reduction in serum concentrations of CRP following administration of Simvastatin (WMD: -0.29; 95% CI: -0.49, -0.10; I² = 88.5%). Combining 6 effect sizes from 5 studies, we found a significant reduction in serum IL-6 concentrations after Atorvastatin therapy (WMD: -2.13; 95% CI: -3.96, -0.30; I² = 98.6%).

CONCLUSIONS

In conclusion, we found that statins administration in apparently healthy people or those with chronic diseases help reducing serum CRP concentrations. In addition, Atorvastatin administration resulted in reduced serum IL-6 concentrations in these people.

Risk and Benefits of Statins in Glucose Control Management of Type II Diabetes

Worldwide statins are considered to be the first-line pharmacological treatment for dyslipidemia and reducing the risk of coronary heart disease. However, recently various studies have shown its adverse effect on glucose control among diabetic patients and the U.S. Food and Drug Administration have revised statin drug labels to include information that increases in fasting serum glucose and glycated hemoglobin levels have been reported. This systematic review objective is to evaluate the risks and benefits of statins in glucose control management of type 2 diabetes patients based on the 44 published journal articles included and obtained through MEDLINE full text, PubMed, Science Direct, Pro Quest, SAGE, Taylor and Francis Online, Google Scholar, High Wire, and Elsevier Clinical Key. Statins were found to affect glucose control through several ways, namely, by affecting insulin production and secretion by β-pancreatic cells, insulin resistance, insulin uptake by the muscles and adipocytes and production of adipokines. Current evidence available shows that most of the statins give unfavorable side effects with regards to glucose control among diabetic patients. A dose-dependent and time-dependent effect was also observed in some statins which may be present among other statins as well.

Sex-related differences in the associations between plasma free fatty acid levels and clinical features in patients with hypertrophic cardiomyopathy

Background

Previous studies have indicated that inefficient energy utilization may play a pivotal role in hypertrophic cardiomyopathy (HCM). However, whether plasma free fatty acid (FFA), a main energy substrate of heart, has an effect on HCM remains unclear. Besides, several studies have suggested sex-related differences in HCM features and FFA metabolism. Here, we aimed to explore the association between plasma FFA levels and HCM and potential effects of sex on this relation.

Methods

A total of 412 patients (age 47.8 ± 12.7 years, 243 males (59.0%)) with HCM were recruited. Complete medical history was collected. Echocardiography and cardiovascular magnetic resonance imaging (CMRI) were performed. Fasting plasma FFA was determined by clinical laboratory. Left ventricular mass (LVM), maximum wall thickness (MWT), and left atrium diameter (LAD) were assessed with CMRI.

Results

The median FFA levels were 0.38 (interquartile range (IQR) 0.27–0.52) mmol/L in men and 0.40 (IQR 0.30–0.59) mmol/L in women. The FFA levels were significantly lower in men compared with those in women (p = 0.005). Compared with women, men had greater LVM index (LVMI) (96.8 ± 37.6 vs. 78.6 ± 31.5 g/m², p < 0.001). FFA levels in male patients correlated positively with LVM, LVMI, LAD, cholesterol levels, high-density lipoprotein-cholesterol (HDL-C) levels, heart rate, and systolic blood pressure (SBP). However, none of these variables were significantly associated with sqrt (FFA) in female patients except a borderline correlation of LAD (p = 0.050). Multiple linear regression analysis was performed in male patients and revealed that HDL-C (β = 0.191, p = 0.002), heart rate (β = 0.182, p = 0.004), SBP (β = 0.167, p = 0.007), LVMI (β = 0.132, p = 0.032), and LAD (β = 0.165, p = 0.009) were independently associated with increasing FFA levels.

Conclusions

In patients with HCM, LVMI, LAD, HDL-C, SBP, and heart rate were independently associated with increasing plasma FFA levels in males, whereas not in females. These results suggest that sex may affect the pathogenesis of HCM through influencing FFA metabolism. And these sex-related differences should be taken into account in therapeutic approaches to influence myocardial FFA metabolism in HCM.

Statin therapy and plasma free fatty acids: a systematic review and meta-analysis of controlled clinical trials

AIM

The aim of this meta-analysis was to evaluate the effect of statin therapy on plasma FFA concentrations in a systematic review and meta-analysis of controlled clinical trials.

METHODS

PubMed-Medline, SCOPUS, Web of Science and Google Scholar databases were searched (from inception to February 16 2015) to identify controlled trials evaluating the impact of statins on plasma FFA concentrations. A systematic assessment of bias in the included studies was performed using the Cochrane criteria. A random effects model and generic inverse variance method were used for quantitative data synthesis. Sensitivity analysis was conducted using the leave-one-out method. Random effects meta-regression was performed using unrestricted maximum likelihood method to evaluate the impact of potential moderators.

RESULTS

Meta-analysis of data from 14 treatment arms indicated a significant reduction in plasma FFA concentrations following treatment with statins (weighted mean difference (WMD) -19.42%, 95% CI -23.19, --15.64, P < 0.001). Subgroup analysis confirmed the significance of the effect with both atorvastatin (WMD -20.56%, 95% CI -24.51, -16.61, P < 0.01) and simvastatin (WMD -18.05%, 95% CI -28.12, -7.99, P < 0.001). Changes in plasma FFA concentrations were independent of treatment duration (slope -0.10, 95% CI -0.30, 0.11, P = 0.354) and magnitude of reduction in plasma low density lipoprotein cholesterol concentrations (slope 0.55, 95% CI -0.17, 1.27, P = 0.133) by statins.

CONCLUSIONS

The results of the present study suggest that statin therapy may lower plasma FFA concentrations. The cardiovascular and metabolic significance of this finding requires further investigation.

Interaction between Glucose and Lipid Metabolism: More than Diabetic Dyslipidemia

Glucose and lipid metabolism are linked to each other in many ways. The most important clinical manifestation of this interaction is diabetic dyslipidemia, characterized by elevated triglycerides, low high density lipoprotein cholesterol (HDL-C), and predominance of small-dense LDL particles. However, in the last decade we have learned that the interaction is much more complex. Hypertriglyceridemia and low HDL-C cannot only be the consequence but also the cause of a disturbed glucose metabolism. Furthermore, it is now well established that statins are associated with a small but significant increase in the risk for new onset diabetes. The underlying mechanisms are not completely understood but modulation of 3-hydroxy-3-methylglutaryl-coenzyme A (HMG CoA)-reductase may play a central role as genetic data indicate that mutations resulting in lower HMG CoA-reductase activity are also associated with obesity, higher glucose concentrations and diabetes. Very interestingly, this statin induced increased risk for new onset type 2 diabetes is not detectable in subjects with familial hypercholesterolemia. Furthermore, patients with familial hypercholesterolemia seem to have a lower risk for type 2 diabetes, a phenomenon which seems to be dose-dependent (the higher the low density lipoprotein cholesterol, the lower the risk). Whether there is also an interaction between lipoprotein(a) and diabetes is still a matter of debate.

Lipid-induced Muscle Insulin Resistance Is Mediated by GGPPS via Modulation of the RhoA/Rho Kinase Signaling Pathway

Elevated circulating free fatty acid levels are important contributors to insulin resistance in the muscle and liver, but the underlying mechanisms require further elucidation. Here, we show that geranylgeranyl diphosphate synthase 1 (GGPPS), which is a branch point enzyme in the mevalonic acid pathway, promotes lipid-induced muscle insulin resistance through activation of the RhoA/Rho kinase signaling pathway. We have found that metabolic perturbation would increase GGPPS expression in the skeletal muscles of db/db mice and high fat diet-fed mice. To address the metabolic effects of GGPPS activity in skeletal muscle, we generated mice with specific GGPPS deletions in their skeletal muscle tissue. Heterozygous knock-out of GGPPS in the skeletal muscle improved systemic insulin sensitivity and glucose homeostasis in mice fed both normal chow and high fat diets. These metabolic alterations were accompanied by activated PI3K/Akt signaling and enhanced glucose uptake in the skeletal muscle. Further investigation showed that the free fatty acid-stimulated GGPPS expression in the skeletal muscle was able to enhance the geranylgeranylation of RhoA, which further induced the inhibitory phosphorylation of IRS-1 (Ser-307) by increasing Rho kinase activity. These results implicate a crucial role of the GGPPS/RhoA/Rho kinase/IRS-1 pathway in skeletal muscle, in which it mediates lipid-induced systemic insulin resistance in obese mice. Therefore, skeletal muscle GGPPS may represent a potential pharmacological target for the prevention and treatment of obesity-related type 2 diabetes.

Vascular injury in diabetic db/db mice is ameliorated by atorvastatin: role of Rac1/2-sensitive Nox-dependent pathways

Oxidative stress [increased bioavailability of reactive oxygen species (ROS)] plays a role in the endothelial dysfunction and vascular inflammation, which underlie vascular damage in diabetes. Statins are cholesterol-lowering drugs that are vasoprotective in diabetes through unknown mechanisms. We tested the hypothesis that atorvastatin decreases NADPH oxidase (Nox)-derived ROS generation and associated vascular injury in diabetes. Lepr(db)/Lepr(db) (db/db) mice, a model of Type 2 diabetes and control Lepr(db)/Lepr(+) (db/+) mice were administered atorvastatin (10 mg/kg per day, 2 weeks). Atorvastatin improved glucose tolerance in db/db mice. Systemic and vascular oxidative stress in db/db mice, characterized by increased plasma TBARS (thiobarbituric acid-reactive substances) levels and exaggerated vascular Nox-derived ROS generation respectively, were inhibited by atorvastatin. Cytosol-to-membrane translocation of the Nox regulatory subunit p47(phox) and the small GTPase Rac1/2 was increased in vessels from db/db mice compared with db/+ mice, an effect blunted by atorvastatin. The increase in vascular Nox1/2/4 expression and increased phosphorylation of redox-sensitive mitogen-activated protein kinases (MAPKs) was abrogated by atorvastatin in db/db mice. Pro-inflammatory signalling (decreased IκB-α and increased NF-κB p50 expression, increased NF-κB p65 phosphorylation) and associated vascular inflammation [vascular cell adhesion molecule-1 (VCAM-1) expression and vascular monocyte adhesion], which were increased in aortas of db/db mice, were blunted by atorvastatin. Impaired acetylcholine (Ach)- and insulin (INS)-induced vasorelaxation in db/db mice was normalized by atorvastatin. Our results demonstrate that, in diabetic mice, atorvastatin decreases vascular oxidative stress and inflammation and ameliorates vascular injury through processes involving decreased activation of Rac1/2 and Nox. These findings elucidate redox-sensitive and Rac1/2-dependent mechanisms whereby statins protect against vascular injury in diabetes.

Statin-associated incident diabetes: a literature review

OBJECTIVE

To evaluate available evidence for incident diabetes associated with statin use and offer some practical management considerations.

DATA SOURCES

A literature search was performed using MEDLINE from 2000 to October 2013. The following MESH terms and text key words alone or in combination were included: 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors, HMG-CoA reductase inhibitors, statins, incident diabetes, new-onset diabetes, insulin resistance, impaired insulin secretion, meta-analysis, cohort study, and observational study.

STUDY SELECTION

Analyzed studies were published in English and investigated incident diabetes associated with statin use.

DATA EXTRACTION

Author consensus determined study inclusion in this review, focusing on observational studies and meta-analyses.

DATA SYNTHESIS

Since the report of incident diabetes associated with rosuvastatin, an unexpected finding in the Justification for the Use of Statins in Prevention: an Intervention Trial Evaluating Rosuvastatin, safety concerns with statins have emerged. Results of observational studies and meta-analyses show association of incident diabetes with statin use in patients with concomitant risk factors for diabetes. A pharmacodynamic mechanism has yet to be delineated, and individual statins may behave differently. Whether cardiovascular (CV) risk will increase with statin-associated incident diabetes remains unclear.

CONCLUSION

Review of current, available clinical data suggest a possible association between statin use and incident diabetes in patients with underlying diabetes risk factors. Although study data may be insufficient to change the current practice paradigm, clinicians should vigilantly monitor for incident diabetes in patients on statins. Patients with a low risk of CV disease and high risk of diabetes should reconsider statin use and focus on lifestyle management.

Statin treatment, new-onset diabetes, and other adverse effects: a systematic review

Statin treatment prevents cardiovascular diseases probably beyond their lipid-lowering effect. Increasing evidence suggests that statins might increase the risk of new-onset diabetes; however, diabetes is known to increase the risk of cardiovascular diseases. The majority of the literature suggests an increased risk of new-onset diabetes in patients treated with statins in a number of different settings and that the risk appears greatest among the more potent statins. Furthermore, a dose-response curve has been shown between statin treatment and the development of diabetes. Possible mechanisms include muscle insulin resistance, lower expression of GLUT-4 in adipocytes impairing glucose tolerance and suppression of glucose-induced elevation of intracellular Ca(2+) level. However, other side effects have been reported such as increased risk of myotoxicity, increased liver enzymes, cataracts, mood disorders, dementias, hemorrhagic stroke and peripheral neuropathy, which should maybe be added to the increased risk of new-onset diabetes, when considering the risk- benefit ratio of statin treatment.

Effects of ezetimibe/simvastatin 10/20 mg vs. atorvastatin 20 mg on apolipoprotein B/apolipoprotein A1 in Korean patients with type 2 diabetes mellitus: results of a randomized controlled trial

BACKGROUND

Although the efficacy of ezetimibe/simvastatin and atorvastatin on traditional lipid parameters has been studied extensively, the apolipoprotein B/apolipoprotein A1 (ApoB/ApoA1) ratio, which has a better predictive value for cardiovascular events, has not previously been used as a primary endpoint in these two treatment groups.

OBJECTIVE

Our objective was to compare the efficacy and safety of ezetimibe/simvastatin 10/20 mg versus atorvastatin 20 mg once daily in Korean patients with type 2 diabetes mellitus.

STUDY DESIGN

This study was an open-label, randomized, controlled study. Type 2 diabetes patients with high levels of low-density lipoprotein (LDL) cholesterol (>100 mg/dL) were randomized to receive ezetimibe/simvastatin or atorvastatin.

MAIN OUTCOME MEASURE

The primary endpoint was the difference in the percent change of ApoB/ApoA1 at 12 weeks, and secondary endpoints were changes in lipid profiles, glycosylated hemoglobin (HbA1c), homeostatic model assessment (HOMA) index, and C-reactive protein.

RESULTS

In total, 132 patients (66 for each group) were enrolled and randomized. After 12 weeks of treatment, the ApoB/ApoA1 ratio was significantly reduced in both groups; however, the difference of changes between the two groups was not statistically significant (ezetimibe/simvastatin -38.6 ± 18.0 % vs. atorvastatin -34.4 ± 15.5 %; p = 0.059). There were no significant differences in changes to total cholesterol, LDL cholesterol, high-density lipoprotein cholesterol, triglycerides, ApoB, and ApoB48 between the two groups. However, the increments of ApoA1 were significantly greater in the ezetimibe/simvastatin group than in the atorvastatin group (2.8 ± 10.0 vs. -1.8 ± 9.8 %; p = 0.002). In the per-protocol analysis, improvement in ApoB/ApoA1 was significantly greater in the ezetimibe/simvastatin group (-42.8 ± 11.8 vs. -36.7 ± 13.2 %; p = 0.019). The changes in HbA1c, HOMA index, and C-reactive protein were comparable between the two groups. The adverse reaction rate was similar between the two groups (24.2 vs. 34.9 %; p = 0.180).

CONCLUSION

Ezetimibe/simvastatin 10/20 mg is comparable to atorvastatin 20 mg for the management of dyslipidemia, and may have more favorable effects on apolipoprotein profiles than atorvastatin 20 mg in Korean patients with type 2 diabetes mellitus.

Problems and possible solutions for therapy with statins

Despite issues about the value of statins, benefit for high cardiovascular (CV) risk outweighs problems. However, the practitioner must be aware of concerns, be prepared to respond, and justify statin usage. Symptoms of statin-related myopathy are of more concern than stated by pharmaceutical companies. Occurrence of myopathy symptoms, estimated to be up to 10.4%, can decrease statin adherence of high CV risk patients. Dosage modification, or use of pitavastatin, may help the problematic patient. There are concerns that there may be little benefit of statins for primary prevention in women. However, evidence appears to support statin use in women at high CV risk, both in primary and secondary prevention. Abandoning low-density lipoprotein cholesterol (LDL-C) as a valid target is unwarranted; there is much evidence to support "lower is better." The practitioner must be aware of the complicated processes causing atherosclerosis and when to incorporate new approaches to disease management. Tailoring therapy for CV risk, when indicated, may contribute further to LDL-C reduction. Liver inflammation can occur with statins but is of minimal concern; frequently, statins alleviate the problem. Unless liver transaminases are over three times normal, a statin should be prescribed, if indicated. The net effect of statins on cognition appears to be zero-no harm, no benefit. Despite reports of improved cognition, statins should not be prescribed for this. With diabetes mellitus (DM), statins can increase incidence, but the CV benefit far outweighs any risk. Therefore, statins should be prescribed in DM to reduce CV risk. Statins are a major medical contribution when used appropriately.

Rosuvastatin does not affect fasting glucose, insulin resistance, or adiponectin in patients with mild to moderate hypertension

The effects of statins on insulin resistance and new-onset diabetes are unclear. The purpose of this study was to evaluate the effects of rosuvastatin on insulin resistance and adiponectin in patients with mild to moderate hypertension. In a randomized, prospective, single-blind study, 53 hypertensive patients were randomly assigned to the control group (n=26) or the rosuvastatin (20 mg once daily) group (n=27) during an 8-week treatment period. Both groups showed significant improvements in systolic blood pressure and flow-mediated dilation (FMD) after 8 weeks of treatment. Rosuvastatin treatment improved total cholesterol, low-density lipoprotein (LDL)-cholesterol, and triglyceride levels. The control and rosuvastatin treatment groups did not differ significantly in the change in HbA1c (3.0±10.1% vs. -1.3±12.7%; p=0.33), fasting glucose (-1.3±18.0% vs. 2.5±24.1%; p=0.69), or fasting insulin levels (5.2±70.5% vs. 22.6±133.2%; p=0.27) from baseline. Furthermore, the control and rosuvastatin treatment groups did not differ significantly in the change in the QUICKI insulin sensitivity index (mean change, 2.2±11.6% vs. 3.6±11.9%; p=0.64) or the HOMA index (11.6±94.9% vs. 32.4±176.7%; p=0.44). The plasma adiponectin level increased significantly in the rosuvastatin treatment group (p=0.046), but did not differ significantly from that in the control group (mean change, 23.2±28.4% vs. 23.1±27.6%; p=0.36). Eight weeks of rosuvastatin (20 mg) therapy resulted in no significant improvement or deterioration in fasting glucose levels, insulin resistance, or adiponectin levels in patients with mild to moderate hypertension.

Cardiovascular disease: primary prevention, disease modulation and regenerative therapy

Cardiovascular primary prevention and regeneration programs are the contemporary frontiers in functional metabolic vascular medicine. This novel science perspective harnesses our inherent ability to modulate the interface between specialized gene receptors and bioavailable nutrients in what is labeled as the nutrient-gene interaction. By mimicking a natural process through the conveyance of highly absorbable receptor specific nutrients, it is feasible to accelerate cell repair and optimize mitochondrial function, thereby achieving cardiovascular cure. We performed a comprehensive review of PubMed, EMBASE and Cochrane Review databases for articles relating to cardiovascular regenerative medicine, nutrigenomics and primary prevention, with the aim of harmonizing their roles within contemporary clinical practice. We searched in particular for large-scale randomized controlled trials on contemporary cardiovascular pharmacotherapies and their specific adverse effects on metabolic pathways which feature prominently in cardiovascular regenerative programs, such as nitric oxide and glucose metabolism. Scientific research on 'cardiovascular-free' centenarians delineated that low sugar and low insulin are consistent findings. As we age, our insulin level increases. Those who can decelerate the rapidity of this process are prompting their cardiovascular rejuvenation. It is beginning to dawn on some clinicians that contemporary treatments are not only failing to impact on our most prevalent diseases, but they may be causing more damage than good. Primary prevention programs are crucial elements for a better outcome. Cardiovascular primary prevention and regeneration programs have enhanced clinical efficacy and quality of life and complement our conventional endovascular practice.

Inhibition of lipolysis in Type 2 diabetes normalizes glucose disposal without change in muscle glycogen synthesis rates

Suppression of lipolysis by acipimox is known to improve insulin-stimulated glucose disposal, and this is an important phenomenon. The mechanism has been assumed to be an enhancement of glucose storage as glycogen, but no direct measurement has tested this concept or its possible relationship to the reported impairment in insulin-stimulated muscle ATP production. Isoglycaemic-hyperinsulinaemic clamps with [13C]glucose infusion were performed on Type 2 diabetic subjects and matched controls with measurement of glycogen synthesis by 13C MRS (magnetic resonance spectroscopy) of muscle. 31P saturation transfer MRS was used to quantify muscle ATP turnover rates. Glucose disposal rates were restored to near normal in diabetic subjects after acipimox (6.2 ± 0.8 compared with 4.8 ± 0.6 mg·kgffm⁻¹·min⁻¹; P<0.01; control 6.6 ± 0.5 mg·kgffm⁻¹·min⁻¹; where ffm, is fat-free mass). The increment in muscle glycogen concentration was 2-fold higher in controls compared with the diabetic group, and acipimox administration to the diabetic group did not increase this (2.0 ± 0.8 compared with 1.9 ± 1.1 mmol/l; P<0.05; control, 4.0 ± 0.8 mmol/l). ATP turnover rates did not increase during insulin stimulation in any group, but a modest decrease in the diabetes group was prevented by lowering plasma NEFAs (non-esterified fatty acids; 8.4 ± 0.7 compared with 7.1 ± 0.5 μmol·g⁻¹·min⁻¹; P<0.05; controls 8.6 ± 0.8 μmol·g⁻¹·min⁻¹). Suppression of lipolysis increases whole-body glucose uptake with no increase in the rate of glucose storage as glycogen but with increase in whole-body glucose oxidation rate. ATP turnover rate in muscle exhibits no relationship to the acute metabolic effect of insulin.

Predictors of new-onset diabetes in patients treated with atorvastatin: results from 3 large randomized clinical trials

OBJECTIVES

We sought to examine the incidence and clinical predictors of new-onset type 2 diabetes mellitus (T2DM) within 3 large randomized trials with atorvastatin.

BACKGROUND

Statin therapy might modestly increase the risk of new-onset T2DM.

METHODS

We used a standard definition of diabetes and excluded patients with prevalent diabetes at baseline. We identified baseline predictors of new-onset T2DM and compared the event rates in patients with and without new-onset T2DM.

RESULTS

In the TNT (Treating to New Targets) trial, 351 of 3,798 patients randomized to 80 mg of atorvastatin and 308 of 3,797 randomized to 10 mg developed new-onset T2DM (9.24% vs. 8.11%, adjusted hazard ratio [HR]: 1.10, 95% confidence interval [CI]: 0.94 to 1.29, p = 0.226). In the IDEAL (Incremental Decrease in End Points Through Aggressive Lipid Lowering) trial, 239 of 3,737 patients randomized to atorvastatin 80 mg/day and 208 of 3,724 patients randomized to simvastatin 20 mg/day developed new-onset T2DM (6.40% vs. 5.59%, adjusted HR: 1.19, 95% CI: 0.98 to 1.43, p = 0.072). In the SPARCL (Stroke Prevention by Aggressive Reduction in Cholesterol Levels) trial, new-onset T2DM developed in 166 of 1,905 patients randomized to atorvastatin 80 mg/day and in 115 of 1,898 patients in the placebo group (8.71% vs. 6.06%, adjusted HR: 1.37, 95% CI: 1.08 to 1.75, p = 0.011). In each of the 3 trials, baseline fasting blood glucose, body mass index, hypertension, and fasting triglycerides were independent predictors of new-onset T2DM. Across the 3 trials, major cardiovascular events occurred in 11.3% of patients with and 10.8% of patients without new-onset T2DM (adjusted HR: 1.02, 95% CI: 0.77 to 1.35, p = 0.69).

CONCLUSIONS

High-dose atorvastatin treatment compared with placebo in the SPARCL trial is associated with a slightly increased risk of new-onset T2DM. Baseline fasting glucose level and features of the metabolic syndrome are predictive of new-onset T2DM across the 3 trials.

Comparative effects of rosuvastatin and atorvastatin on glucose metabolism and adipokine levels in non-diabetic patients with dyslipidaemia: a prospective randomised open-label study

AIMS

The impact of statins on glucose metabolism and adipokines remains controversial. We compared the effects of rosuvastatin and atorvastatin on glucose homeostasis, insulin sensitivity (IS), adiponectin and leptin levels as well as systemic inflammation in non-diabetic patients with dyslipidaemia.

METHODS

Thirty-six patients were randomly assigned to 10 mg/day of rosuvastatin (n = 18) or 20 mg/day of atorvastatin (n = 18) for 12 weeks. Total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), non-HDL-C, triglycerides (TG), fasting plasma glucose, insulin, homeostasis model assessment-insulin resistance (HOMA-IR), quantitative IS check index (QUICKI), adiponectin, leptin and high-sensitivity C-reactive protein (hsCRP) were measured at baseline and after 4 and 12 weeks.

RESULTS

Both statins significantly lowered TC, LDL-C, non-HDL-C and TG compared with baseline. Only rosuvastatin caused a significant reduction in insulin and HOMA-IR levels (-35%, p = 0.005 and -33%, p = 0.011 respectively) and a significant increase in QUICKI (+11%, p = 0.003) at 12 weeks. In terms of adipokines and hsCRP, no difference was observed after 4 and 12 weeks of treatment with either statin.

CONCLUSIONS

Rosuvastatin compared with atorvastatin resulted in significant improvements in IS indices. No significant changes in adiponectin, leptin or hsCRP levels were observed at 4 and 12 weeks of treatment with either statin.

Comparison of fibrate, ezetimibe, low- and high-dose statin therapy for the dyslipidemia of the metabolic syndrome in a mouse model

BACKGROUND AND AIM

The treatment-of-choice for the optimal management of the dyslipidemia of the metabolic syndrome (MetS) is not clearly defined. We compared the efficacy of 4 drug regimes for the management of this dyslipidemia in a mouse model.

MATERIALS AND METHODS

A total of 60 C57Bl6 mice comprised the study group. The first 10 received standard mouse food for the whole experiment (control group). The remaining 50 mice received atherogenic diet for 14 weeks until the development of the MetS. The mice were then divided into 5 groups: the 1st group continued receiving atherogenic diet, while the other 4 groups received atherogenic diet plus ezetimibe (10 mg/kg per day), fenofibrate (100 mg/kg per day), low-dose atorvastatin (10 mg/kg per day), or high-dose (40 mg/kg per day) atorvastatin, respectively, for another 8 weeks.

RESULTS

High-dose atorvastatin treatment achieved the best lipid profile compared with low-dose atorvastatin, ezetimibe, and fibrate therapy. The lipid profile of mice receiving atherogenic diet plus high-dose atorvastatin treatment was similar with mice on regular chow.

CONCLUSIONS

High-dose atorvastatin treatment resulted in optimization of the lipid profile in the presence of a high-fat atherogenic diet in a mouse model. Our results suggest that high-dose atorvastatin treatment may be the optimal treatment option for the dyslipidemia associated with MetS. Nevertheless, verification of these results in humans is required before any definite conclusions can be drawn.

Atorvastatin prevents ischemic limb loss in type 2 diabetes: role of p53

AIM

Diabetic peripheral artery disease (PAD) is prone to be aggressive and recent reports have demonstrated that p53 accumulation may be responsible for impaired wound healing in diabetes. Statins has been demonstrated to facilitate p53 degradation by activating its specific ubiquitin ligase, MDM2. The aim of this study was to determine whether atorvastatin (ATR) improves the outcome of diabetic PAD through MDM2-mediated reduction of p53.

METHODS

Male KK/Ay mice (9 weeks old) were treated with ATR (2 mg/kg/day p.o.) or vehicle for 2 weeks and subjected to ischemic hindlimb operation to generate a diabetic PAD model. Incidences of amputation and changes of p53/MDM2 signaling in each ischemic limb were assessed 2 weeks after the operation (at 13 weeks of age). Effects of ATR on the insulin resistance of age-matched (13-week-old) and unoperated KK/Ay mice were assessed by the glucose tolerance test, circulating adiponectin concentration, and changes in insulin signaling (IRS-1/Akt phosphorylation).

RESULTS

In intact KK/Ay, ATR treatment mitigated insulin resistance without affecting cholesterol levels. All diabetic PAD models exhibited autoamputation (100%); however, ATR treatment partially restored the limb loss (41.7%). The p53 expression level in the ischemic limb of ATR-treated KK/Ay was significantly decreased and MDM2 phosphorylation level was markedly increased in tandem with the activation of Akt. Hypoxia mimetic iron chelator deferroxamine promoted p53 accumulation in H9c2 myoblast cells by suppressing the Akt/MDM2 pathway, which was restored by ATR.

CONCLUSIONS

ATR was found to restore ischemic limb loss in diabetes by augmenting p53 degradation through direct activation of the Akt/MDM2 pathway in skeletal muscle.

Differential metabolic effects of distinct statins

Reciprocal relationships between endothelial dysfunction and insulin resistance suggest that therapies improving endothelial dysfunction will simultaneously improve insulin sensitivity and other metabolic parameters. However, previous studies with some statins either did not alter insulin sensitivity or promoted insulin resistance despite significant improvements in endothelial dysfunction and decreases in circulating pro-inflammatory markers. This may be due to pleiotropic or off-target effects of some statins to cause insulin resistance by diverse mechanisms unrelated to endothelial dysfunction. Indeed, there is evidence of other differential metabolic actions of distinct statins including effects on hydroxymethylglutaryl-CoA reductase inhibition, isoprotenoid synthesis, calcium release, glucose transport, insulin secretion, and/or insulin resistance. Pravastatin increases expression of adiponectin mRNA, enhances adiponectin secretion, increases plasma levels of adiponectin, and enhances insulin sensitivity in mice and humans. Clinical studies including large scale randomized controlled trials demonstrate potential differences between individual statins, with pravastatin promoting risk reduction for new onset of diabetes. Conversely, other statins including atorvastatin, rosuvastatin, and simvastatin all promote significant increase in this risk. Given the frequent concordance of metabolic diseases including diabetes, obesity, and metabolic syndrome with cardiovascular diseases associated with hyperlipidemia, it is important to understand the potential metabolic risks and benefits of therapies with distinct statins. In this review, we discuss these differential effects of statins on metabolic homeostasis and insulin sensitivity.

Presence of the metabolic syndrome is associated with shorter time to castration-resistant prostate cancer

BACKGROUND

Metabolic syndrome (MS) is a set of risk factors that includes obesity and insulin resistance and has been implicated in the development of prostate cancer. Its impact on androgen deprivation therapy (ADT) efficacy has not been studied.

PATIENTS AND METHODS

Retrospective study of prostate cancer patients seen from 1998 to 2005 in a medical oncology clinic. MS, as defined by modified Adult Treatment Panel III criteria, was assessed at the time of initiation of ADT. The study end points were time to prostate-specific antigen (PSA) progression and overall survival (OS) from time of starting ADT.

RESULTS

Eighty-two patients treated with ADT and data to assess for presence of MS were identified. Median age in men with and without MS was 70 years and 49% of the patients evaluated met criteria for MS. Median time to PSA progression for patients with MS was 16 versus 36 months without MS (P=0.003). The median OS for patients with MS was 36.5 months after commencing ADT compared with 46.7 months for those patients without MS (P=0.061).

CONCLUSIONS

This preliminary data suggest that MS is a risk factor for earlier development of castration-resistant prostate cancer and support the need for a prospective evaluation of this finding.

Niemann-Pick C1-Like 1 deletion in mice prevents high-fat diet-induced fatty liver by reducing lipogenesis

Niemann-Pick C1-Like 1 (NPC1L1) mediates intestinal absorption of dietary and biliary cholesterol. Ezetimibe, by inhibiting NPC1L1 function, is widely used to treat hypercholesterolemia in humans. Interestingly, ezetimibe treatment appears to attenuate hepatic steatosis in rodents and humans without a defined mechanism. Over-consumption of a high-fat diet (HFD) represents a major cause of metabolic disorders including fatty liver. To determine whether and how NPC1L1 deficiency prevents HFD-induced hepatic steatosis, in this study, we fed NPC1L1 knockout (L1-KO) mice and their wild-type (WT) controls an HFD, and found that 24 weeks of HFD feeding causes no fatty liver in L1-KO mice. Hepatic fatty acid synthesis and levels of mRNAs for lipogenic genes are substantially reduced but hepatic lipoprotein-triglyceride production, fatty acid oxidation, and triglyceride hydrolysis remain unaltered in L1-KO versus WT mice. Strikingly, L1-KO mice are completely protected against HFD-induced hyperinsulinemia under both fed and fasted states and during glucose challenge. Despite similar glucose tolerance, L1-KO relative WT mice are more insulin sensitive and in the overnight-fasted state display significantly lower plasma glucose concentrations. In conclusion, NPC1L1 deficiency in mice prevents HFD-induced fatty liver by reducing hepatic lipogenesis, at least in part, through attenuating HFD-induced insulin resistance, a state known to drive hepatic lipogenesis through elevated circulating insulin levels.

Alpha-receptor blockade improves muscle perfusion and glucose uptake in heart failure

AIMS

Alpha-adrenergic receptor-mediated vasoconstriction might underlie the insulin resistance seen in conditions associated with increased sympathetic tone, like chronic heart failure (CHF). Alpha-adrenergic receptor blockade by phentolamine could improve forearm blood flow (FBF) and forearm glucose uptake (FGU) in CHF patients.

METHODS AND RESULTS

In 8 CHF patients and in 12 healthy volunteers, FBF (plethysmography) and FGU were measured in both forearms during a 150 min hyperinsulinaemic euglycaemic clamp procedure. During the final 30 min of the clamp, phentolamine was infused into one arm (experimental arm) at a dose of 5.0 μg; min(-1) dL(-1) of forearm volume. Insulin infusion (t = 0-120 min) increased FGU in the two groups, without affecting FBF. In the CHF group, α-adrenergic receptor blockade by phentolamine (t = 120-150 min) further increased FGU in the experimental arm from 3.0 ± 0.7 to 5.0 ± 0.9 μmol min(-1) dL(-1) (P = 0.03). Forearm glucose uptake in the contralateral forearm remained unchanged. In the control group, phentolamine infusion did not increase FGU in the experimental forearm. The increase in blood flow in response to phentolamine was similar in both groups (CHF: 2.1 ± 0.3-7.5 ± 1.7 mL min(-1) dL(-1), P < 0.001; controls 1.5 ± 0.2-5.5 ± 0.8 mL min(-1) dL(-1), P < 0.001 for both, CHF vs. control, P = 0.2). Phentolamine did not affect FBF in the control arm in either group.

CONCLUSION

Alpha-adrenergic receptor blockade improves FGU in CHF patients. As the increase in FBF is similar in controls and CHF patients, this might be explained by an improved glucose-extraction capacity in CHF patients.

Improved endothelial function with simvastatin but unchanged insulin sensitivity with simvastatin or ezetimibe

In addition to their expected effects on lipid profile, lipid-lowering agents may reduce cardiovascular events because of effects on nonclassic risk factors such as insulin resistance and inflammation. Ezetimibe specifically blocks the absorption of dietary and biliary cholesterol as well as plant sterols. Although it is known that an additional reduction of low-density lipoprotein cholesterol (LDL-C) levels can be induced by the combination of ezetimibe with statins, it is not known if this can enhance some pleiotropic effects, which may be useful in slowing the atherosclerotic process. This study assessed the effects of simvastatin and ezetimibe, in monotherapy or in combination, on markers of endothelial function and insulin sensitivity. Fifty prediabetic subjects with normo- or mild-to-moderate hypercholesterolemia were randomly allocated to 2 groups receiving either ezetimibe (10 mg/d) or simvastatin (20 mg/d) for 12 weeks, after which the drugs were combined for both groups for an additional 12-week period. Clinical and laboratory parameters were measured at baseline and after 12 and 24 weeks of therapy. Homeostasis model assessment of insulin resistance index and the area under the curve of insulin were calculated. As expected, both groups receiving drugs in isolation significantly reduced total cholesterol, LDL-C, apolipoprotein B, and triglyceride levels; and additional reductions were found after the combination period (P < .05). After 12 weeks of monotherapy, plasminogen activator inhibitor-1 levels and urinary albumin excretion were lower in the simvastatin than in the ezetimibe group. No change in homeostasis model assessment of insulin resistance index, area under the curve of insulin, and adiponectin levels was observed after either the monotherapies or the combined therapy. However, simvastatin combined with ezetimibe provoked significant reductions in E-selectin and intravascular cellular adhesion molecule-1 levels that were independent of LDL-C changes. Our findings support claims that simvastatin may be beneficial in preserving endothelial function in prediabetic subjects with normo- or mild-to-moderate hypercholesterolemia. Alternatively, a deleterious effect of ezetimibe on the endothelial function is suggested, considering the increase in intravascular cellular adhesion molecule-1 and E-selectin levels. Simvastatin and ezetimibe, in isolation or in combination, do not interfere with insulin sensitivity.

Effects of Atorvastatin 20 mg, Rosuvastatin 10 mg, and Atorvastatin/Ezetimibe 5 mg/5 mg on Lipoproteins and Glucose Metabolism

The aim of this study was to compare the effects of 3 different statin regimens that have equivalent low-density lipoprotein cholesterol (LDL-C) lowering efficacy on the apolipoprotein B/A1 ratio and glucose metabolism. After a 4-week dietary lead-in, 90 hypercholeserolemic patients were randomly assigned to 1 of 3 treatment groups for 8 weeks: atorvastatin 20 mg, rosuvastatin 10 mg, or atorvastatin/ezetimibe 5 mg/5 mg. At drug treatment week 8, we compared the percentage changes in lipid parameters, apolipoprotein B/A1 ratio, hemoglobin A1c, and homeostasis model assessment-insulin resistance (HOMA-IR) from baseline. Seventy-six patients completed the study and the percentage changes in LDL-C were comparable among the groups. However, the percentage reduction in the apolipoprotein B/A1 ratio was significantly greater in the rosuvastatin group (—47% ± 14%, P = .04) and the combination group (—46% ± 8%, P = .05) than in the atorvastatin group (—39% ± 11%). The percentage increase in hemoglobin A1c was small but significantly greater in the atorvastatin group compared to the combination group (3.0% ± 5.2% and —0.4% ± 4.0%, P = .03). The effect of rosuvastatin on hemoglobin A1c was not different from those of the other 2 regimens. The effects of 3 statin regimens were similar on HOMA-IR. In conclusion, 3 statin regimens have differential effect on apolipoprotein B/A1 and glycemic control after comparable LDL-C reduction.

Evidence for statin therapy in polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is a common endocrine disorder in women of reproductive age group that is associated with increased cardiovascular risk. In addition to its lipid-lowering effects, statin therapy has shown been shown to have beneficial pleiotropic effects that may contribute to their reduction in cardiovascular morbidity and mortality. In this review, the effect of statins on PCOS is discussed with reference to the underlying potential mechanism of action.

Differing effect of statins on insulin sensitivity in non-diabetics: a systematic review and meta-analysis

BACKGROUND

To determine whether individual statins had differing effects on insulin sensitivity (IS) in patients without pre-existing diabetes mellitus.

METHODS

A systematic literature search of MEDLINE, EMBASE and Cochrane CENTRAL was conducted through December 2008. Trials were included if they compared pravastatin, atorvastatin, rosuvastatin or simvastatin to placebo/control, excluded patients with diabetes, and reported data on insulin sensitivity/resistance. IS data was pooled and evaluated as standardized mean differences (SMDs) and 95% confidence interval (CI) using a random-effects model.

RESULTS

16 studies (n=1146) were included, with patients receiving pravastatin in three trials (n=164), atorvastatin in five trials (n=315), rosuvastatin in five trials (n=419), and simvastatin in five trials (n=369). When pooled as a class, statins had no significant impact on IS as compared with placebo/control [SMD -0.084 (95% CI -0.210 to 0.042); p=0.19]. Pravastatin was found to significantly improved IS [SMD 0.342 (95% CI 0.032-0.621); p=0.03], whereas simvastatin significantly worsened IS [SMD -0.321 (95% CI -0.526 to -0.117); p=0.03].

CONCLUSIONS

Statins do not appear to demonstrate a 'class effect' on IS in patients without diabetes. Differences between individual statins likely exist that may partially explain the findings of previously conducted meta-analyses examining the impact of statins on the development of diabetes.

Leg fat mass as measured by dual X-ray absorptiometry (DXA) impacts insulin resistance differently in obese women versus men

OBJECTIVE

To investigate the association between regional fat mass (FM) and insulin resistance and dyslipidaemia in obese women and men.

MATERIAL AND METHODS

Body composition was measured by dual-energy X-ray absorptiometry (DXA) in 109 obese women and 113 obese men. Insulin resistance was measured by (HOMA-IR); insulin sensitivity was estimated by metabolic clearance rate (MCRestOGTT) and insulin secretion by HOMAsecr. Serum lipids were assessed.

RESULTS

In women, leg FM was negatively (favourably) associated with HOMA-IR and cholesterol/HDL-cholesterol ratio (p<0.05). Trunk FM was positively (unfavourably) associated with HOMA-IR. Leg/trunk FM ratio was negatively associated with HOMA-IR (p<0.001), cholesterol/HDL-cholesterol ratio (p<0.001) and triglycerides (p<0.01); positively (favourably) with MCRestOGTT (p<0.01) and HDL-cholesterol (p<0.05). No associations were found in men. In women, multiple regression analysis demonstrated that leg/trunk FM ratio was the only explanatory FM for HOMA-IR and MCRestOGTT (R(2) = 0.23 and R(2) = 0.13, respectively; p<0.001), but postmenopausal status was also of importance (R(2) = 0.23, p = 0.019 and R(2) = 0.29, p = 0.015, respectively).

CONCLUSIONS

Leg FM has a favourable influence on insulin resistance and dyslipidaemia in obese women, but not demonstrated in this cohort of obese men.

The effects of low-dose simvastatin and ezetimibe compared to high-dose simvastatin alone on post-fat load endothelial function in patients with metabolic syndrome: a randomized double-blind crossover trial

BACKGROUND AND AIMS

Insulin resistance is associated with postprandial hyperlipidemia and endothelial dysfunction. Patients with metabolic syndrome, characterized by insulin resistance, are at increased cardiovascular risk. The aim of the present study was to investigate whether a similar low-density lipoprotein cholesterol (LDL-c) reduction with combination therapy of low-dose simvastatin and ezetimibe or with high-dose simvastatin alone has similar effects on (post-fat load) endothelial function.

METHODS

Randomized, double blind, crossover trial in 19 male obese patients with metabolic syndrome with high-dose simvastatin 80 mg versus combination therapy of low-dose simvastatin 10 mg with ezetimibe 10 mg. Fasting and post-fat load lipids and endothelial function (brachial artery flow-mediated dilation) were determined.

RESULTS

Fasting LDL-c concentrations (2.1 +/- 0.5 mmol/L) and fasting endothelial function (6.9 +/- 0.8 vs. 7.6 +/- 1.2%) were the same after both treatments. Although post-fat load plasma triglycerides concentrations were higher (3.2 +/- 0.4 vs. 2.6 +/- 0.2 mmol x h/L) with combination therapy compared to monotherapy, ApoB particles were comparable (0.9 +/- 3.3 vs. -0.2 +/- 2.3 g x h/L). Combination therapy did not decrease post-fat load endothelial function (7.6 +/- 1.2 vs. 7.7 +/- 1.6%), contrary to high-dose simvastatin monotherapy (6.9 +/- 0.8 vs. 4.3 +/- 0.6%).

CONCLUSIONS

Combination therapy with low-dose simvastatin and ezetimibe preserved post-fat load endothelial function, contrary to treatment with high-dose simvastatin monotherapy in male metabolic syndrome patients. There were no differences in fasting lipid profiles and endothelial function.

Regional fat mass by DXA: high leg fat mass attenuates the relative risk of insulin resistance and dyslipidaemia in obese but not in overweight postmenopausal women

OBJECTIVE

To investigate the influence of regional fat mass (FM) on insulin resistance and dyslipidaemia in obese postmenopausal women (BMI >30 kg/m(2)) compared to overweight women (BMI <30 kg/m(2)). Leg FM may attenuate the increased risk of cardiovascular disease and diabetes imposed by increased trunk FM in normal and overweight postmenopausal women.

MATERIAL AND METHODS

Cross-sectional and consecutively referred patients comprising 63 obese and 36 overweight postmenopausal women. Body composition and regional FM by dual X-ray absorptiometry (DXA), fasting glucose, fasting insulin and C-peptide, insulin resistance by homeostasis model assessment (HOMA-IR), insulin sensitivity by quantitative insulin sensitivity check index (QUICKI) and metabolic clearance rate (MCRestOGTT), insulin secretion (HOMAsecr) and serum lipids were assessed.

RESULTS

In obese subjects, leg FM was favourably associated with HOMA-IR (p<0.05), QUICKI (p<0.05), fasting glucose (p<0.05), fasting insulin (p<0.05), HOMAsecr (p<0.05) and total cholesterol/HDL ratio (p<0.05). Trunk FM was unfavourably associated with MCRestOGTT (p<0.01), QUICKI (p<0.05) and fasting insulin (p<0.05). Compared to leg FM, leg/trunk FM ratio was more strongly associated with fasting insulin (p<0.001), fasting C-peptide (p<0.001), HOMA-IR (p<0.001), MCRestOGTT (p<0.001), QUICKI (p<0.001), HOMAsecr (p<0.001), fasting glucose (p<0.01) and triglycerides (p<0.01). Stepwise multiple regression demonstrated that leg/trunk FM ratio was the most important variable with partial R (2) = 0.26 (p<0.001) for HOMA and R (2) = 0.37 (p<0.001) when QUICKI was used as the dependent variable. In overweight women, no associations between fat mass and parameters of insulin resistance or dyslipidaemia were found.

CONCLUSIONS

A high leg/trunk FM ratio as measured by DXA may give relative protection against diabetes and cardiovascular disease in obese postmenopausal women, but not in overweight women.

Comparative effects of atorvastatin and simvastatin on the plasma total homocysteine levels in women with polycystic ovary syndrome: a prospective randomized study

OBJECTIVE

To test the hypothesis that statins improve hyperhomocysteinemia in women with polycystic ovary syndrome (PCOS).

DESIGN

A prospective randomized study.

SETTING

University Hospital.

PATIENT(S)

Fifty-two women with PCOS and 52 women matched for age and body mass index as controls.

INTERVENTION(S)

Patients were randomly divided into two groups for treatment: group 1, atorvastatin, 20 mg daily (n = 26), and group 2, simvastatin, 20 mg daily (n = 26). Blood samples were obtained before and after treatment.

MAIN OUTCOME MEASURE(S)

Serum homocysteine levels.

RESULT(S)

After 12 weeks of treatment, serum homocysteine levels in group 1 had decreased from 14.3 +/- 2.9 to 10.6 +/- 1.7 micromol/L; in group 2, the levels decreased from 13.6 +/- 2.1 to 11.1 +/- 1.9 micromol/L. Both two groups, free testosterone and total testosterone declined statistically significantly (38.3% and 36.5%; and 40.6% and 46.0%, respectively). In group 1, vitamin B(12) increased from 362.1 +/- 107 to 478.7 +/- 267 pg/mL; in group 2, it increased from 391.3 +/- 107 to 466 +/- 211 pg/mL, but the change did not reach statistical significance. There was a considerable decline in the homeostatic model assessment index in group 1 (40.0% to 32.1%).

CONCLUSION(S)

Treatment with statins in women with PCOS leads to decreases in serum homocysteine levels.

A novel membrane-based anti-diabetic action of atorvastatin

We recently found that chromium picolinate (CrPic), a nutritional supplement thought to improve insulin sensitivity in individuals with impaired glucose tolerance, enhances insulin action by lowering plasma membrane (PM) cholesterol. Recent in vivo studies suggest that cholesterol-lowering statin drugs benefit insulin sensitivity in insulin-resistant patients, yet a mechanism is unknown. We report here that atorvastatin (ATV) diminished PM cholesterol by 22% (P<0.05) in 3T3-L1 adipocytes. As documented for CrPic, this small reduction in PM cholesterol enhanced insulin action. Replenishment of cholesterol mitigated the positive effects of ATV on insulin sensitivity. Co-treatment with CrPic and ATV did not amplify the extent of PM cholesterol loss or insulin sensitivity gain. In addition, analyses of insulin signal transduction suggest a non-signaling basis of both therapies. Our data reveal an unappreciated beneficial non-hepatic effect of statin action and highlight a novel mechanistic similarity between two recently recognized therapies of impaired glucose tolerance.

Mineralocorticoid receptor blockade reverses obesity-related changes in expression of adiponectin, peroxisome proliferator-activated receptor-gamma, and proinflammatory adipokines

BACKGROUND

In obesity, decreases in adiponectin and increases in proinflammatory adipokines are associated with heart disease. Because adipocytes express mineralocorticoid receptor (MR) and MR blockade reduces cardiovascular inflammation and injury, we tested the hypothesis that MR blockade reduces inflammation and expression of proinflammatory cytokines in adipose tissue and increases adiponectin expression in adipose tissue and hearts of obese mice.

METHODS AND RESULTS

We determined the effect of MR blockade (eplerenone, 100 mg/kg per day for 16 weeks) on gene expression in retroperitoneal adipose and heart tissue from obese, diabetic db/db mice (n=8) compared with untreated obese, diabetic db/db mice (n=10) and lean, nondiabetic db/+ littermates (n=11). Expression of tumor necrosis factor-alpha, monocyte chemoattractant protein-1, plasminogen activator inhibitor type 1, and macrophage protein CD68 increased, and expression of adiponectin and peroxisome proliferator-activated receptor-gamma decreased in retroperitoneal adipose tissue from obese versus lean mice. In addition, adiponectin expression in heart was reduced in obese versus lean mice. MR blockade prevented these obesity-related changes in gene expression. Furthermore, treatment of undifferentiated preadipocytes with aldosterone (10(-8) mol/L for 24 hours) increased mRNA levels of tumor necrosis factor-alpha and monocyte chemoattractant protein-1 and reduced mRNA and protein levels of peroxisome proliferator-activated receptor-gamma and adiponectin, supporting a direct aldosterone effect on gene expression.

CONCLUSIONS

MR blockade reduced expression of proinflammatory and prothrombotic factors in adipose tissue and increased expression of adiponectin in heart and adipose tissue of obese, diabetic mice. These effects on adiponectin and adipokine gene expression may represent a novel mechanism for the cardioprotective effects of MR blockade.

Effects of atorvastatin on red-blood cell Na(+)/Li(+) countertransport in hyperlipidemic patients with and without hypertension

BACKGROUND

To explore the effect of short-term cholesterol-lowering treatment with atorvastatin on erythrocyte sodium-lithium countertransport (Na(+)/Li(+) CT) activity.

METHODS

Group A consisted of 30 patients (14 men) with mild essential hypertension (systolic blood pressure (SBP), 140-159 mm Hg and/or diastolic BP, 90-99 mm Hg) and primary hypercholesterolemia low-density lipoprotein (LDL) cholesterol >4.1 mmol/l and triglycerides (TG) <2.8 mmol/l), group B of 30 normotensive patients (16 men) with primary hypercholesterolemia, while 37 (18 men) healthy volunteers comprised the control group. After a 6-week dietary lead-in, all eligible patients were prescribed 20 mg/day of atorvastatin. Anthropometric data, blood-pressure (BP) measurements and determinations of lipid, non-lipid metabolic parameters (including homeostasis model assessment index, (HOMA-IR)) and erythrocyte Na(+)/Li(+) CT activity were collected at baseline and after 12 weeks of treatment.

RESULTS

At baseline Na(+)/Li(+) CT activity was significantly higher in group A and B compared with the control group and correlated directly with obesity indices, systolic and diastolic BP, total cholesterol, LDL-cholesterol, TG, apolipoprotein B (apoB), HOMA-IR, uric acid and inversely with high-density lipoprotein (HDL)-cholesterol and apoA1. Systolic and diastolic BP levels, HOMA-IR and Na(+)/Li(+) CT activity were significantly decreased after atorvastatin treatment in both patient groups. The reduction in Na(+)/Li(+) CT activity correlated with baseline Na(+)/Li(+) CT activity and the changes in HOMA-IR values.

CONCLUSIONS

Short-term treatment with atorvastatin for patients with hypercholesterolemia, and with or without essential hypertension, is associated with a significant reduction in the erythrocyte Na(+)/Li(+) CT activity, BP levels and insulin resistance independent of concomitant changes in lipid parameters.

Statin modulates insulin signaling and insulin resistance in liver and muscle of rats fed a high-fat diet

Recent studies have shown that statins might have relevant effects on insulin resistance in animal models and in humans. However, the molecular mechanisms that account for this improvement in insulin sensitivity are not well established. The aim of the present study was to investigate the effect of a statin on insulin sensitivity and insulin signaling in liver and muscle of rats fed on a high-fat diet (HFD) for 4 weeks, treated or not with lovastatin during the last week. Our data show that treatment with lovastatin results in a marked improvement in insulin sensitivity characterized by an increase in glucose disappearance rate during the insulin tolerance test. This increase in insulin sensitivity was associated with an increase in insulin-induced insulin receptor (IR) tyrosine phosphorylation and, in parallel, a decrease in IR serine phosphorylation and association with PTP1B. Our data also show that lovastatin treatment was associated with an increase in insulin-stimulated insulin receptor substrate (IRS) 1/phosphatidylinositol 3-kinase/Akt pathway in the liver and muscle of HFD-fed rats in parallel with a decrease in the inflammatory pathway (c-jun N-terminal kinase and I kappa beta kinase (IKKbeta)/inhibitor of kappaB/nuclear factor kappaB) related to insulin resistance. In summary, statin treatment improves insulin sensitivity in HFD-fed rats by reversing the decrease in the insulin-stimulated IRS-1/phosphatidylinositol 3-kinase/Akt pathway in liver and muscle. The effect of statins on insulin action is further supported by our findings that HFD rats treated with statin show a reduction in IRS-1 serine phosphorylation, I kappa kinase (IKK)/inhibitor of kappaB/nuclear factor kappaB pathway, and c-jun N-terminal kinase activity, associated with an improvement in insulin action. Overall, these results provide important new insight into the mechanism of statin action in insulin sensitivity.