Effects of atorvastatin and pravastatin on glucose tolerance in diabetic rats mildly induced by streptozotocin

Diabetic cardiomyopathy: Early diagnostic biomarkers, pathogenetic mechanisms, and therapeutic interventions

Diabetic cardiomyopathy (DCM) mainly refers to myocardial metabolic dysfunction caused by high glucose, and hyperglycemia is an independent risk factor for cardiac function in the absence of coronary atherosclerosis and hypertension. DCM, which is a severe complication of diabetes, has become the leading cause of heart failure in diabetic patients. The initial symptoms are inconspicuous, and patients gradually exhibit left ventricular dysfunction and eventually develop total heart failure, which brings a great challenge to the early diagnosis of DCM. To date, the underlying pathological mechanisms of DCM are complicated and have not been fully elucidated. Although there are therapeutic strategies available for DCM, the treatment is mainly focused on controlling blood glucose and blood lipids, and there is a lack of effective drugs targeting myocardial injury. Thus, a large percentage of patients with DCM inevitably develop heart failure. Given the neglected initial symptoms, the intricate cellular and molecular mechanisms, and the lack of available drugs, it is necessary to explore early diagnostic biomarkers, further understand the signaling pathways involved in the pathogenesis of DCM, summarize the current therapeutic strategies, and develop new targeted interventions.

Comparative effect of statin intensity between prediabetes and type 2 diabetes mellitus after implanting newer-generation drug-eluting stents in Korean acute myocardial infarction patients: a retrospective observational study

Background

Comparative studies regarding the long-term clinical outcomes of statin intensity between acute myocardial infarction (AMI) patients with prediabetes and those with type 2 diabetes mellitus (T2DM), after successful implantation of newer-generation drug-eluting stents (DES) with statin treatment, are limited. We compared the 2-year clinical outcomes between these patients.

Methods

A total of 11,612 AMI patients were classified as statin users (n = 9893) and non-users (n = 1719). Thereafter, statin users were further divided into high-intensity (n = 2984) or low-moderate-intensity statin (n = 6909) treatment groups. Those in these two groups were further classified into patients with normoglycemia, prediabetes, and T2DM. The major outcomes were the occurrence of major adverse cardiac events (MACE), defined as all-cause death, recurrent myocardial infarction (Re-MI), or any repeat coronary revascularization.

Results

After adjusting for both high-intensity and low-moderate-intensity statin users, the cumulative incidences of MACE (p = 0.737, p = 0.062, respectively), all-cause death, Re-MI, and any repeat revascularization were similar between the prediabetes and T2DM groups. In the total study population, both high-intensity and low-moderate-intensity statin treatments showed comparable results. However, in the patients who enrolled after October 2012, the cumulative incidences of MACE (aHR 1.533; 95% CI 1.144–2.053; p = 0.004) and any repeat revascularization (aHR, 1.587; 95% CI 1.026–2.456; p = 0.038) were significantly lower in high-intensity statin users than in low-moderate intensity statin users. The beneficial effects of high-intensity compared to low-moderate-intensity statin therapy were more apparent in the normoglycemia group than hyperglycemia group, as it reduced the cumulative incidences of MACE (aHR 1.903; 95% CI 1.203–3.010; p = 0.006) and any repeat revascularization (aHR 3.248; 95% CI 1.539–6.854; p = 0.002).

Conclusions

In this retrospective registry study, prediabetes and T2DM groups showed comparable clinical outcomes, after administering both high-intensity and low-moderate-intensity statin treatments. However, these results are likely to be clearly proved by further studies, especially in patients with AMI who are being treated in contemporary practice.

Trial registration

Retrospectively registered.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12872-021-02198-w.

Diabetogenic effects of cardioprotective drugs

Drugs that protect against cardiovascular events in the patient with diabetes may also positively or negatively affect glycaemic control in the patient with established diabetes and may induce the development of diabetes in the predisposed patient. Mainly through increasing insulin resistance, beta-blockers, statins and high-dose diuretics have the potential to worsen glycaemic control. Dihydropyridine calcium channel blockers, low-dose diuretics, vasodilating beta-blockers, alpha-blockers and pitavastatin have little or no effect on glycaemic control. Blockers of the renin-angiotensin-aldosterone system, colesevelam, ranolazine and verapamil, through slowing breakdown of bradykinin, vasodilation, increasing cholecystokinin levels, blocking sodium channels and decreasing beta cell apoptosis, may improve glycaemic control and avoid the development of diabetes.

Comparison of streptozotocin-induced diabetes at different moments of the life of female rats for translational studies

Animal models are widely used for studying diabetes in translational research. However, methods for induction of diabetes are conflicting with regards to their efficacy, reproducibility and cost. A comparison of outcomes between the diabetic models is still unknown, especially full-term pregnancy.To understand the comparison, we analyzed the streptozotocin (STZ)-induced diabetes at three life-different moments during the neonatal period in Sprague-Dawley female rats: at the first (D1), second (D2) and fifth (D5) day of postnatal life. At adulthood (90 days; D90), the animals were submitted to an oral glucose tolerance test (OGTT) for diabetic status confirmation. The diabetic and control rats were mated and sacrificed at full-term pregnancy for different analyses. Group D1 presented a higher mortality percentage after STZ administration than groups D2 and D5. All diabetic groups presented higher blood glucose levels as compared to those of the control group, while group D5 had higher levels of glycemia compared with other groups during OGTT. The diabetic groups showed impaired reproductive outcomes compared with the control group. Group D1 had lower percentages of mated rats and D5 showed a lower percentage of a full-term pregnancy. Besides that, these two groups also showed the highest percentages of inadequate fetal weight. In summary, although all groups fulfill the diagnosis criteria for diabetes in adult life, in our investigation diabetes induced on D5 presents lower costs and higher efficacy and reproducibility for studies involving diabetes-complicated pregnancy.

Supplementation of pyrroloquinoline quinone with atorvastatin augments mitochondrial biogenesis and attenuates low grade inflammation in obese rats

Mitochondrial dysfunction and Inflammation play a significant role in the manifestation of the co-morbidities of obesity. The study deciphered the impact of Pyrroloquinoline quinone (PQQ) per se and with Atorvastatin (ATS) on high fat, 10% fructose diet (HFFD) induced obese rats expressing low-grade inflammation, dyslipidemia, and mitochondrial dysfunction. HFFD was fed for 10 weeks followed by treatment for 5 weeks with ATS 10 or 20 mg/kg, PQQ 10 or 20 mg/kg, p.o. per se or their combinations. The impact on blood glucose, lipid profile and serum insulin, TNF-α, IL-1β, IL-18, IL-6 was estimated. Gene and protein expression of peroxisome proliferator-activated receptor gamma coactivator-1 alpha (PGC 1α), Sirtuin 1 (SIRT1), Mitochondrial transcriptional factor A (TFAM) and augmented mitochondrial DNA (mtDNA), NOD like receptor protein 3 (NLRP3) and Caspase 1 was assessed. Rats receiving PQQ and ATS revealed significant decrease in body weights, anthropometric parameter, and adipose tissue vis-à-vis positive control. PQQ alone and with ATS improved glucose tolerance, lipid profile, insulin indices and lowered serum levels of inflammatory cytokines IL-18, IL-1β, TNF-α and IL-6 along with a rise in adiponectin. PQQ supplementation with ATS upregulated the mRNA expression of PGC 1α, SIRT1, TFAM and augmented mtDNA while downregulating inflammatory markers NLRP3 and Caspase 1. PQQ supplementation with atorvastatin holds therapeutic promise to effectively combat mitochondrial dysfunction and chronic low-grade inflammation in obesity.

Statin use increased new-onset diabetes in hypercholesterolemic individuals: Data from the Korean National Health Insurance Service-National Health Screening Cohort database (NHIS-HEALS)

AIM

We investigated the association between statin use and new-onset diabetes (NODM) in Korean adults with hypercholesterolemia.

METHODS

This study performed based on data from the National Health Insurance Service-National Health Screening Cohort for the years from 2002 to 2015. Statin users classified as high- or low- users according to medication possession ratio. Statin non-users consisted of hypercholesterolemic participants who never used statin over the entire follow-up period. 21,469 participants (10,880 statin users, 10,589 statin non-users) with a median follow-up period of 12.5 years were included. We estimated the NODM risk based on the survival analyses. In particular, to adjust for confounding effects, we considered Cox proportional hazards regression models over three stages.

RESULTS

Compared to non-users, statin users had a significantly higher risk for NODM. The fully adjusted hazard ratios (aHRs) (95% confidential intervals [95% CIs]) of statin users for NODM were 1.43 (1.31-1.57) in men, and 1.86 (1.66-2.10) in women, respectively after adjusted confounding factors including age and lifestyle factors. Compared to high-users, aHRs (95% CIs) of low-users for NODM were 1.16 (1.03-1.30) and 1.28 (1.16-1.43) in men and women, respectively.

CONCLUSIONS

In hypercholesterolemic patients, statin users have a higher risk of NODM than non-users.

Statins: Pharmacokinetics, Pharmacodynamics and Cost-Effectiveness Analysis

Cardiovascular diseases secondary to atherosclerosis are the primary causes of early death and disability worldwide and dyslipidaemia represents one of the most important modifiable risk factors. Among lipid abnormalities that define it, low-density lipoprotein cholesterol (LDL-C) is the primary target of therapy, since multiple randomized controlled trials have shown the positive impact of its reduction on atherosclerosis development. For their ability to lower LDL-C levels, statins are the most studied drugs in cardiovascular disease prevention, of proven utility in slowing the progression or even determining regression of atherosclerosis. In addition, they have ancillary proprieties, with positive effects on the mechanisms involved in the development of atherosclerosis and cardiovascular morbidity and mortality, the so-called "pleiotropic mechanisms". Although sharing the same mechanism of action, the different chemical and pharmacological characteristics of each kind of statins affect their absorption, bioavailability, plasma protein binding properties, excretion and solubility. In this overview, we analysed pharmacokinetic and pharmacodynamic mechanisms of this class of drugs, specifying the differences among the molecules, along with the economic aspects. Detailed knowledge of characteristics and differences of each kind of available statin could help the physician in the correct choice, based also on patient's clinical profile, of this essential tool with a demonstrated high cost-effectiveness both in primary than in the secondary prevention of cardiovascular disease.

The Vascular Consequences of Metabolic Syndrome: Rodent Models, Endothelial Dysfunction, and Current Therapies

Metabolic syndrome is characterized by visceral obesity, dyslipidemia, hyperglycemia and hypertension, and affects over one billion people. Independently, the components of metabolic syndrome each have the potential to affect the endothelium to cause vascular dysfunction and disrupt vascular homeostasis. Rodent models of metabolic syndrome have significantly advanced our understanding of this multifactorial condition. In this mini-review we compare the currently available rodent models of metabolic syndrome and consider their limitations. We also discuss the numerous mechanisms by which metabolic abnormalities cause endothelial dysfunction and highlight some common pathophysiologies including reduced nitric oxide production, increased reactive oxygen species and increased production of vasoconstrictors. Additionally, we explore some of the current therapeutics for the comorbidities of metabolic syndrome and consider how these benefit the vasculature.

Associations of statin use with glycaemic traits and incident type 2 diabetes

AIMS

There are several epidemiological studies on the association between statins and incident diabetes, but most of them lack details. In this study, we aimed to investigate the association of statin use with glycaemic traits and incident type 2 diabetes.

METHODS

Using the prospective population-based Rotterdam Study, we included 9535 individuals free from diabetes at baseline (>45 years) during the study period between 1997 and 2012. Linear regression analysis was applied to examine the cross-sectional associations between statin use and glycaemic traits including fasting blood serum of glucose and insulin concentrations, and insulin resistance. In a longitudinal follow-up study, we applied a Cox regression analysis to determine adjusted hazard ratios (HR) for incident type 2 diabetes in new users of statins.

RESULTS

The mean age at baseline was 64.3 ± 10.1 years and 41.7% were men. In the fully adjusted model, compared to never users of statins, baseline use of statins was associated with higher concentrations of serum fasting insulin (β = 0.07; 95% CI: 0.02-0.13) and insulin resistance (β = 0.09; 95% CI: 0.03-0.14). Ever use of statins was associated with a 38% higher risk of incident type 2 diabetes (HR = 1.38; 95% CI: 1.09-1.74). This risk was more prominent in subjects with impaired glucose homeostasis and in overweight/obese individuals.

CONCLUSIONS

Individuals using statins may be at higher risk for hyperglycaemia, insulin resistance and eventually type 2 diabetes. Rigorous preventive strategies such as glucose control and weight reduction in patients when initiating statin therapy might help minimize the risk of diabetes.

Long-term effects of combined simvastatin and metformin treatment on the clinical abnormalities and ovulation dysfunction in single young women with polycystic ovary syndrome

The aim of the current work was to investigate the value of the long term effects of combined use of simvastatin and metformin treatment for a year versus the effects of their individual treatment on the clinical, biochemical abnormalities, and ovulation dysfunction in young single women with polycystic ovary syndrome (PCOS). It was a randomized, double-blind controlled study. Where two hundreds (n = 200) single young women with PCOS were randomized into seventy (n = 70) women using simvastatin 20 mg daily combined with metformin 500 mg three times daily considered as group A (study group), and another 2 sixty five (n = 65) women groups using simvastatin and metformin individually as a single treatment use, and considered as groups (B & C), respectively. Medications period extended for twelve months treatment period. The primary outcome measures were the changes in serum androgen levels (testosterone, androstendione, and dehydro-epiandrostenion sulfate-DHEAS), LH, FSH, LH/FSH ratio, and insulin resistance (IR), in addition to menstrual regularity, hirsutism, BMI, and W/H ratio. Spontaneous ovulation, confirmed with both trans-abdominal sonography (TAS) and luteal serum progesterone as well had been also evaluated. After 12 months' treatment, in group A serum testosterone showed significant decline by 37%, with significant drop in LH serum level (51%) and a marked decline of the LH/FSH ratio (53%). IR showed a significant improvement in groups A and C but still relatively higher in group B. There was also a clear decrease of total cholesterol (36%), low-density lipoprotein (LDL; 48%), and triglycerides (26%), and increased high-density lipoprotein (HDL) by 24% in groups A and B. Improved menstrual regularity and decreased hirsutism, acne, ovarian volume, and BMI had been significantly noticed in the study groups A and C, although still relatively higher in group C. Spontaneous ovulation had been confirmed in group A: songoraphically (TAS), and biochemically (progesterone >10 ng) in 10 women after the first six months treatment, and 26 at the end of 12 months treatment, compared to 5 & 8 in group B, and 2 & 5 in group C, respectively. Combined simvastatin and metformin treatment showed significant improvement of PCOS clinical and ovarian dysfunction abnormalities much better than their individual treatment.

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.

Effects of Pravastatin on Type 1 Diabetic Rat Heart with or without Blood Glycemic Control

Although statins have been suggested to attenuate the progression of diabetic cardiomyopathy, its effect without glycemic control remains unclear. Therefore, we evaluated the effect of pravastatin on diabetic rat hearts according to glycemic control. Rats were randomly divided into five groups: control (C), diabetes (D), diabetes with insulin (I), diabetes with pravastatin (P), and diabetes with insulin and pravastatin (IP). Eight weeks after allocated treatments, the heart was extracted and analyzed following echocardiography. Cardiac fibrosis was measured using Masson's trichrome stain. Cardiac expression of collagen I/III, matrix metalloproteinase (MMP)-2, MMP-9, and angiotensin-converting enzyme (ACE)/ACE2 was evaluated by immunohistochemistry and/or Western blot. Enzyme-linked immunosorbent assay was used for measuring reactive oxygen species (ROS). Diabetic groups without glycemic control (D and P) showed significantly impaired diastolic function and increased levels of cardiac fibrosis, collagen I/III, MMP-2, MMP-9, and ROS production. However, there were little significant differences in the outcomes among the control and two glucose-controlled diabetic groups (I and IP). Groups C and IP showed more preserved ACE2 and lower ACE expressions than the other groups did (D, I, and P). Our study suggested glycemic control would be more important to attenuate the progression of diabetic cardiomyopathy than pravastatin medication.

To study the effect of high dose Atorvastatin 40mg versus 80mg in patients with dyslipidemia

Objective

Primary objective was to compare the effects of atorvastatin 40 mg vs 80 mg on LDL-C in Indian patients with atherosclerotic dyslipidemia. Secondary objectives were to compare the effects of atorvastatin 40 mg vs 80 mg on HDL-C and triglycerides and also comparing of side effects (myopathy, hepatotoxicity and new onset diabetes mellitus) of both doses.

Method

This Study is A Prospective, randomized, open-label, comparative study. This study was conducted on 240 patients of dyslipidemia (as per ACC/AHA 2013 lipid guidelines) attending the OPD/wards/CCU of department of cardiology, Sir Ganga Ram Hospital. They were randomly divided into 2 groups of 120 each. Group A consisted patients who received Atorvastatin 40 mg daily and Group B Atorvastatin 80 mg daily. The follow up period was 6 months.

Results

At 3 and 6 month follow up, Atorvastatin 40 mg leads to mean LDL cholesterol reduction of 47.18 ± 20.81 & 50.03 ± 18.06 respectively. While Atorvastatin 80 mg results in LDL reduction as 50.11 ± 15.85 & 52.30 ± 13.72. The comparison between two doses revealed a non-significant difference (p = .118 & p = .149 respectively).

At 6 months of follow up, few patients reported myalgia (2 in group A and 7 in Group B). The difference between groups was significant (p = .045). Although none of our patient had significant elevation of CPK.

Conclusion

This study concluded that both doses of atorvastatin (40 & 80 mg) are equally efficacious in improving dyslipidemia but higher dose leads to more incidence of myalgia.

Effect of Atorvastatin on Glycaemic Parameters in Normoglycaemic and Prediabetic Subjects: A Prospective, Panel Study

INTRODUCTION

Type 2 diabetes is associated with obesity and dyslipidemia, which are risk factor for cardiovascular disease. With recent FDA approved indications for statins being widened because of its lipid lowering and pleiotropic effects, statins are currently amongst the most widely used drugs in patients with or without diabetes. Although cardiovascular risk is reduced by statin therapy, its association with the development of diabetes is disputed.

AIM

This study was conducted to evaluate the effect of Atorvastatin on glycaemic status of normoglycaemic and prediabetic individuals.

MATERIALS AND METHODS

An observational, prospective panel study was conducted on 75 subjects who were on Atorvastatin therapy. After baseline data collection and investigations, subjects were recruited depending on their glycaemic status into three groups: normoglycaemic, Impaired Fasting Glucose (IFG) and Impaired Glucose Tolerance (IGT) group. Atorvastatin therapy was continued and the subjects were followed every 6 months up to 18 months. At every follow up all glycaemic parameters were evaluated and subjects were assessed for continuation of statin therapy, dosing schedule and possible adverse drug reactions.

RESULT

All three groups as a whole, irrespective of dose of Atrovastatin therapy, showed a statistically significant (p<0.0001) increase in all glycaemic parameters. In normoglycaemic group with low dose Atorvastatin, there was no significant change in 2-hour Post Prandial Blood Sugar (PPBS) but change in HbA1c% (p=0.0004) and FBS (p<0.0001) was significant, whereas, with high dose, changes in 2-hr PPBS and HbA1c % were significant from 6 months onwards. In IFG group, both with low and high dose of Atorvastatin, there was significant change in all glycaemic parameters from 12 months onwards. In case of IGT, especially with high dose Atorvastatin, significant changes were evident from 6 months onwards.

CONCLUSION

Atorvastatin therapy especially with higher dose was found to be associated with glucose intolerance in normoglycaemics and also caused progression towards diabetes in prediabetic individuals.

Impact of statin therapy on plasma leptin concentrations: a systematic review and meta-analysis of randomized placebo-controlled trials

OBJECTIVES

The effects of statins on insulin sensitivity, metabolic homeostasis and adipokines in humans are controversial. Several studies have investigated the impact of statin therapy on plasma leptin concentrations but the results have been inconsistent. The aim of the present study was to conduct a systematic review and meta-analysis of available evidence to calculate the effect size of statin therapy in changing serum leptin concentrations.

METHODS

A systematic search in PubMed-Medline, SCOPUS, Web of Science and Google Scholar databases was performed to identify randomized placebo-controlled trials investigating the effect of statins on plasma leptin concentrations. A random-effects model and generic inverse variance method were used for meta-analysis. Sensitivity analysis, risk-of-bias evaluation and publication bias assessment were carried out using standard methods. Random-effects meta-regression was used to evaluate the impact of treatment duration on the estimated effect size.

RESULTS

Six trials, with a total of 425 subjects, met the eligibility criteria. Overall, statin therapy had no significant effect on leptin levels (weighted mean difference -0.32 ng ml^-1 , 95% confidence nterval: -2.94, 2.30, P = 0.813). This effect was robust in the sensitivity analysis and in subgroup analyses of trials with <12 or ≥12 weeks' duration. There was no association between the duration of statin therapy and changes in plasma leptin levels. Furthermore, there was no differential effect of hydrophilic and lipophilic statins on plasma leptin concentrations.

CONCLUSION

Unless more consistent evidence becomes available in the future, the hypothesis of a relationship between statin use and serum leptin concentrations seem to be unfounded.

Statin Use, Diabetes Incidence and Overall Mortality in Normoglycemic and Impaired Fasting Glucose Patients

BACKGROUND

The association between the use of statins and the risk of diabetes and increased mortality within the same population has been a source of controversy, and may underestimate the value of statins for patients at risk.

OBJECTIVE

We aimed to assess whether statin use increases the risk of developing diabetes or affects overall mortality among normoglycemic patients and patients with impaired fasting glucose (IFG).

DESIGN AND PARTICIPANTS

Observational cohort study of 13,508 normoglycemic patients (n = 4460; 33% taking statins) and 4563 IFG patients (n = 1865; 41% taking statin) among residents of Olmsted County, Minnesota, with clinical data in the Mayo Clinic electronic medical record and at least one outpatient fasting glucose test between 1999 and 2004. Demographics, vital signs, tobacco use, laboratory results, medications and comorbidities were obtained by electronic search for the period 1999-2004. Results were analyzed by Cox proportional hazards models, and the risk of incident diabetes and mortality were analyzed by survival curves using the Kaplan-Meier method.

MAIN MEASURES

The main endpoints were new clinical diagnosis of diabetes mellitus and total mortality.

KEY RESULTS

After a mean of 6 years of follow-up, statin use was found to be associated with an increased risk of incident diabetes in the normoglycemic (HR 1.19; 95% CI, 1.05 to 1.35; p = 0.007) and IFG groups (HR 1.24; 95%CI, 1.11 to 1.38; p = 0.0001). At the same time, overall mortality decreased in both normoglycemic (HR 0.70; 95% CI, 0.66 to 0.80; p < 0.0001) and IFG patients (HR 0.77, 95% CI, 0.64 to 0.91; p = 0.0029) with statin use.

CONCLUSION

In general, recommendations for statin use should not be affected by concerns over an increased risk of developing diabetes, since the benefit of reduced mortality clearly outweighs this small (19-24%) risk.

Different effects of statins on induction of diabetes mellitus: an experimental study

Background

To determine the effect of different statins on the induction of diabetes mellitus.

Materials and methods

Four statins (atorvastatin, pravastatin, rosuvastatin, and pitavastatin) were used. Cytotoxicity, insulin secretion, glucose-stimulated insulin secretion, and G₀/G₁ phase cell cycle arrest were investigated in human pancreas islet β cells, and glucose uptake and signaling were studied in human skeletal muscle cells (HSkMCs).

Results

Human pancreas islet β cells treated with 100 nM atorvastatin, pravastatin, rosuvastatin, and pitavastatin had reduced cell viability (32.12%, 41.09%, 33.96%, and 29.19%, respectively) compared to controls. Such cytotoxic effect was significantly attenuated by decreasing the dose to 10 and 1 nM, ranged from 1.46% to 17.28%. Cells treated with 100 nM atorvastatin, pravastatin, rosuvastatin, and pitavastatin had a reduction in the rate of insulin secretion rate by 34.07%, 30.06%, 26.78%, and 19.22%, respectively. The inhibitory effect was slightly attenuated by decreasing the dose to 10 and 1 nM, ranging from 10.84% to 29.60%. Insulin secretion stimulated by a high concentration of glucose (28 mmol/L) was significantly higher than a physiologic concentration of glucose (5.6 mmol/L) in all treatment groups. The glucose uptake rates at a concentration of 100 nM were as follows: atorvastatin (58.76%) < pravastatin (60.21%) < rosuvastatin (72.54%) < pitavastatin (89.96%). We also found that atorvastatin and pravastatin decreased glucose transporter (GLUT)-2 expression and induced p-p38 MAPK levels in human pancreas islet β cells. Atorvastatin, pravastatin, and rosuvastatin inhibited GLUT-4, p-AKT, p-GSK-3β, and p-p38 MAPK levels in HSkMCs.

Conclusion

Statins similar but different degree of effects on pancreas islet β cells damage and induce insulin resistance in HSkMC.

Atorvastatin delays the glucose clearance rate in hypercholesterolemic rabbits

The administration of statin might increase the risk of new-onset diabetes in hypercholesterolemic patients based on the recent clinical evidence. However, the causal relationship must be clarified and confirmed in animal experiments. Therefore, we mimicked hypercholesterolemia by feeding rabbits a high-cholesterol diet (HCD) and performed 16 weeks of atorvastatin administration to investigate the effect of statin on glucose metabolism. The intravenous glucose tolerance test showed that plasma glucose levels in the statin-treated rabbits were consistently higher and that there was a slower rate of glucose clearance from the blood than in HCD rabbits. The incremental area under the curve for glucose in the statin-treated rabbits was also significantly larger than in the HCD rabbits. However, there was no significant difference between the two groups in the intravenous insulin tolerance test. The glucose-lowering ability of exogenous insulin was not impaired by statin treatment in hypercholesterolemic rabbits. The administration of a single dose of statin did not affect glucose metabolism in normal rabbits. The statin also significantly increased the levels of high-density lipoprotein cholesterol, alanine aminotransferase and aspartate transaminase and decreased plasma levels of total cholesterol, triglycerides and low-density lipoprotein cholesterol in the hypercholesterolemic rabbits, whereas it did not affect plasma levels of glucose and insulin. The current results showed that atorvastatin treatment resulted in a significant delay of glucose clearance in hypercholesterolemic rabbits, and this rabbit model could be suitable for studying the effects of statin on glucose metabolism.

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.

An investigation into the therapeutic effects of statins with metformin on polycystic ovary syndrome: a meta-analysis of randomised controlled trials

OBJECTIVES

To investigate the therapeutic effects of statins with metformin on polycystic ovary syndrome (PCOS).

SETTINGS

Endocrinology department.

PARTICIPANTS

MEDLINE, EMBASE and Cochrane Central Register of Controlled Trials were searched until October 2014. Studies comparing statins and placebo, as well as the combination of statins and metformin and metformin alone, were included in the analysis.

INTERVENTIONS

Data were independently extracted by two researchers; any convergence was resolved by a third reviewer.

PRIMARY AND SECONDARY OUTCOME MEASURES

The following properties were extracted from the qualified trials to identify the effects of statins: clinical variables, metabolic characteristics, hormone outcomes, sign of inflammation, glucose parameters and insulin outcomes.

RESULTS

Data from four trials comparing statin and metformin with metformin alone were analysed. The combination of statins and metformin decreases the levels of C reactive protein (standardised mean difference (SMD) -0.91; 95% CI -1.81 to -0.02; p=0.046), triglyceride (SMD -1.37; 95% CI -2.46 to -0.28; p=0.014), total cholesterol (SMD -1.28; 95% CI -1.59 to -0.97; p=0.000) and low-density lipoprotein (LDL) cholesterol (SMD -0.74; 95% CI -1.03 to -0.44; p=0.000). However, the combined therapy fails to reduce fasting insulin (SMD -0.92; 95% CI -2.07 to 0.24; p=0.120), homeostasis model assessment of insulin resistance (SMD -1.15; 95% CI -3.36 to 1.06; p=0.309) and total testosterone (SMD -1.12; 95% CI -2.29 to 0.05; p=0.061). Analysis of the five trials comparing statin with placebo shows that statin monotherapy reduces LDL-cholesterol, triglyceride and total cholesterol.

CONCLUSIONS

Combined statin and metformin therapy can improve lipid and inflammation parameters, but cannot effectively improve insulin sensitivity and reduce hyperandrogenism in women with PCOS. A large-scale randomised controlled study must be conducted to ascertain the long-term effects of the therapy.

Pharmacological treatment and therapeutic perspectives of metabolic syndrome

Metabolic syndrome is a disorder based on insulin resistance. Metabolic syndrome is diagnosed by a co-occurrence of three out of five of the following medical conditions: abdominal obesity, elevated blood pressures, elevated glucose, high triglycerides, and low high-density lipoprotein-cholesterol (HDL-C) levels. Clinical implication of metabolic syndrome is that it increases the risk of developing type 2 diabetes and cardiovascular diseases. Prevalence of the metabolic syndrome has increased globally, particularly in the last decade, to the point of being regarded as an epidemic. The prevalence of metabolic syndrome in the USA is estimated to be 34% of adult population. Moreover, increasing rate of metabolic syndrome in developing countries is dramatic. One can speculate that metabolic syndrome is going to induce huge impact on our lives. The metabolic syndrome cannot be treated with a single agent, since it is a multifaceted health problem. A healthy lifestyle including weight reduction is likely most effective in controlling metabolic syndrome. However, it is difficult to initiate and maintain healthy lifestyles, and in particular, with the recidivism of obesity in most patients who lose weight. Next, pharmacological agents that deal with obesity, diabetes, hypertension, and dyslipidemia can be used singly or in combination: anti-obesity drugs, thiazolidinediones, metformin, statins, fibrates, renin-angiotensin system blockers, glucagon like peptide-1 agonists, sodium glucose transporter-2 inhibitors, and some antiplatelet agents such as cilostazol. These drugs have not only their own pharmacologic targets on individual components of metabolic syndrome but some other properties may prove beneficial, i.e. anti-inflammatory and anti-oxidative. This review will describe pathophysiologic features of metabolic syndrome and pharmacologic agents for the treatment of metabolic syndrome, which are currently available.

Antioxidant effects of statins in the management of cardiometabolic disorders

Redox systems are key players in vascular health. A shift in redox homeostasis-that results in an imbalance between reactive oxygen species (ROS) generation and endogenous antioxidant defenses has the potential to create a state of oxidative stress that subsequently plays a role in the pathogenesis of a number of diseases, including those of the cardiovascular and metabolic system. Statins, which are primarily used to reduce the concentration of low-density lipoprotein cholesterol, have also been shown to reduce oxidative stress by modulating redox systems. Studies conducted both in vitro and in vivo support the role of oxidative stress in the development of atherosclerosis and cardiovascular diseases. Oxidative stress may also be responsible for various diabetic complications and the development of fatty liver. Statins reduce oxidative stress by blocking the generation of ROS and reducing the NAD+/NADH ratio. These drugs also have effects on nitric oxide synthase, lipid peroxidation and the adiponectin levels. It is possible that the antioxidant properties of statins contribute to their protective cardiovascular effects, independent of the lipid-lowering actions of these agents. However, possible adverse effects of statins on glucose homeostasis may be related to the redox system. Therefore, studies investigating the modulation of redox signaling by statins are warranted.

Effects of pitavastatin versus atorvastatin on the peripheral endothelial progenitor cells and vascular endothelial growth factor in high-risk patients: a pilot prospective, double-blind, randomized study

BACKGROUND

Circulating endothelial progenitor cells (EPCs) reflect endothelial repair capacity and may be a significant marker for the clinical outcomes of cardiovascular disease. While some high-dose statin treatments may improve endothelial function, it is not known whether different statins may have similar effects on EPCs.This study aimed to investigate the potential class effects of different statin treatment including pitavastatin and atorvastatin on circulating EPCs in clinical setting.

METHODS

A pilot prospective, double-blind, randomized study was conducted to evaluate the ordinary dose of pitavastatin (2 mg daily) or atorvastatin (10 mg daily) treatment for 12 weeks on circulating EPCs in patients with cardiovascular risk such as hypercholesterolemia and type 2 diabetes mellitus (T2DM). Additional in vitro study was conducted to clarify the direct effects of both statins on EPCs from the patients.

RESULTS

A total of 26 patients (19 with T2DM) completed the study. While the lipid-lowering effects were similar in both treatments, the counts of circulating CD34+KDR+EPCs were significantly increased (from 0.021 ± 0.015 to 0.054 ± 0.044% of gated mononuclear cells, P < 0.05) only by pitavastatin treatment. Besides, plasma asymmetric dimethylarginine level was reduced (from 0.68 ± 0.10 to 0.53 ± 0.12 μmol/L, P < 0.05) by atorvastatin, and plasma vascular endothelial growth factor (VEGF) level was increased (from 74.33 ± 32.26 to 98.65 ± 46.64 pg/mL, P < 0.05) by pitavastatin. In the in vitro study, while both statins increased endothelial nitric oxide synthase (eNOS) expression, only pitavastatin increased the phosphorylation of eNOS in EPCs. Pitavastatin but not atorvastatin ameliorated the adhesion ability of early EPCs and the migration and tube formation capacities of late EPCs.

CONCLUSIONS

While both statins similarly reduced plasma lipids, only pitavastatin increased plasma VEGF level and circulating EPCs in high-risk patients, which is probably related to the differential pleiotropic effects of different statins.

TRIAL REGISTRATION

This trial is registered at ClinicalTrials.gov, NCT01386853.

[Rosuvastatin improves insulin sensitivity in overweight rats induced by high fat diet. Role of SIRT1 in adipose tissue]

OBJECTIVE

To study the effects of rosuvastatin on insulin resistance in overweight rats induced by high fat diet, as well as potential mediators.

METHODS

We used male Wistar rats fed with a standard diet (CT) or high fat diet (33.5% fat) (HFD); half of the animals HFD were treated with rosuvastatin (15mg/kg/day) (HFD+Rosu) for 7 weeks.

RESULTS

HFD rats showed increased body, epididymal and lumbar adipose tissue weights. Treatment with Rosu did not modify body weight or the weight of the adipose packages in HFD rat. Plasma glucose and insulin levels and HOMA index were higher in HFD rats, and rosuvastatin treatment reduced them. Leptin/adiponectin ratio in plasma and lumbar adipose tissue were higher in HDF rats, and were reduced by rosuvastatin. SIRT-1, PPAR-γ and GLUT-4 protein expression in lumbar adipose tissue were lower in HFD rats and Rosu normalized expression of the three mediators.

CONCLUSIONS

Rosuvastatin ameliorates insulin sensitivity induced by HFD in rats. This effect is mediated by several mechanisms including reduction of leptin and enhancement of SIRT-1, PPAR-γ and GLUT-4 expression in white adipose tissue. SIRT1 could be considered a major mediator of the beneficial effects of rosuvastatin on insulin sensitivity in overweight rats induced by diet.

How to balance cardiorenometabolic benefits and risks of statins

Statins, 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors, are important for preventing adverse cardiovascular events not only in patients with a high risk of vascular disease but also in those with a low risk, by reducing the levels of low-density lipoprotein cholesterol. Statin is associated with deteriorating glucose homeostasis and an increased risk of diabetes mellitus. Moreover, these off-target effects are dose-dependent; it has also been suggested that renal insult can be caused dose-dependently by statin treatment, in contrast to previous studies showing a renoprotective effect. The 2013 American College of Cardiology/American Heart Association guidelines recommend the use of high-intensity statin therapy, and extend its use to more people at risk of vascular diseases. However, a European committee has expressed concerns about the potential side effects of using statins in a large fraction of the population for extended periods. This is true of Asian people, for whom the disease burden from cardiovascular disorders is not as great as among Western ethnic groups. There are still many unanswered questions on how to balance the cardiovascular benefits with the potential renometabolic risks of statins. Therefore, genetic or pharmacogenetic approaches are needed to define who is more vulnerable to developing diabetes mellitus or acute kidney injury. In particular, more information is required regarding the metabolism of statins, and their off-target or unknown actions and overall impact. These different renometabolic effects of statins should help in formulating optimal therapeutic strategies for patients for reducing overall morbidity and mortality and not just those associated with cardiovascular diseases.

Co-administration of paroxetine and pravastatin causes deregulation of glucose homeostasis in diabetic rats via enhanced paroxetine exposure

AIM

Clinical evidence shows that co-administration of pravastatin and paroxetine deregulates glucose homeostasis in diabetic patients. The aim of this study was to verify this phenomenon in diabetic rats and to elucidate the underlying mechanisms.

METHODS

Diabetes mellitus was induced in male SD rats by a high-fat diet combined with a low-dose streptozotocin injection. The rats were orally administered paroxetine (10 mg/kg) and pravastatin (10 mg/d) or both the drugs daily for 28 d. The pharmacokinetics of paroxetine and pravastatin were examined on d 1 and d 28. Biochemical parameters including serum insulin, glucose and lipids were monitored during the treatments. An insulin-secreting cell line (INS-1) was used for measuring insulin secretion.

RESULTS

In diabetic rats, co-administration of paroxetine and pravastatin markedly increased the concentrations of both the drugs compared with administration of each drug alone. Furthermore, co-administration severely impaired glucose homeostasis in diabetic rats, as demonstrated by significantly increased serum glucose level, decreased serum and pancreatic insulin levels, and decreased pancreatic Insulin-2 mRNA and tryptophan hydroxylase-1 (Tph-1) mRNA levels. Treatment of INS-1 cells with paroxetine (5 and 10 μmol/L) significantly inhibited insulin secretion, decreased the intracellular insulin, 5-HT, Insulin-2 mRNA and Tph-1 mRNA levels. Treatment of the cells with pravastatin (10 μmol/L) significantly stimulated insulin secretion, which was weakened by co-treatment with paroxetine.

CONCLUSION

Paroxetine inhibits insulin secretion at least via decreasing intracellular 5-HT and insulin biosynthesis. The deregulation of glucose homeostasis by co-administration of paroxetine and pravastatin in diabetic rats can be attributed to enhanced paroxetine exposure.

Cardiovascular drugs that increase the risk of new-onset diabetes

The prevalence of type 2 diabetes is increasing worldwide, and diabetes is a strong adverse prognostic factor among patients with cardiovascular (CV) disease. Four classes of drugs that are commonly used for CV risk reduction, statins, niacin, thiazide diuretics, and ß-blockers, have been shown to increase the risk of new-onset diabetes (NOD) by 9% to 43% in meta-analyses or large-scale clinical trials. Clinical predictors for drug-related NOD appear to be similar to the predictors that have been described for NOD unrelated to drugs: fasting blood glucose >100 mg/dL and features of the metabolic syndrome such as body mass index >30 kg/m(2), serum triglycerides >150 mg/dL, and elevated blood pressure, among others. The mechanisms whereby these drugs increase the risk of NOD are incompletely understood, although different hypotheses have been suggested. Lifestyle intervention consisting of diet and exercise has been shown in multiple studies to reduce the risk of NOD by approximately 50%, with persistent benefit during long-term follow-up. In patients at high risk for NOD, niacin should be avoided, and for hypertension, an angiotensin-converting enzyme inhibitor or even a ß1-selective blocker might be a better choice than a standard ß-blocker. For thiazide diuretics and particularly statins, benefit in terms of CV event reduction outweighs the risk of NOD.

Differential metabolic actions of specific statins: clinical and therapeutic considerations

SIGNIFICANCE

Statins, the most widely prescribed drugs in clinical practice, mainly act by reducing the plasma level of low-density lipoprotein (LDL)-cholesterol. A shift in redox homeostasis to an imbalance between reactive oxygen species generation and endogenous antioxidant mechanisms results in oxidative stress that has been implicated in the pathogenesis of various diseases, including those of the cardiovascular system. Beyond their efficacy in lowering LDL cholesterol, statins modulate redox systems that are implicated in the development of atherosclerosis, cardiovascular morbidity, and mortality.

RECENT ADVANCES

Differences in specific statins or their dosages result in differential metabolic actions arising from off-target or unknown mechanisms of action that can have important implications for overall patient morbidity and mortality.

CRITICAL ISSUES

A recent meta-analysis and a combined analysis have suggested that high doses of statins increase the risk of developing type 2 diabetes mellitus, but reduce the risk of cardiovascular events. Thus, it is important to consider the cardiovascular and metabolic context and natural history of diseases when choosing a specific statin therapy for optimal individual patient health over the long term.

FUTURE DIRECTIONS

More information is needed regarding the metabolism of statins, and the off-target or unknown actions of statins in affecting insulin resistance and metabolic homeostasis. The differential metabolic effects of specific statins should be considered in formulating optimal therapeutic strategies to reduce not just cardiovascular-related but also overall patient morbidity and mortality.

Statins and renin-angiotensin system inhibitor combination treatment to prevent cardiovascular disease

Hypercholesterolemia and hypertension are common risk factors for cardiovascular disease (CVD). Updated guidelines emphasize target reductions of overall cardiovascular risks. Experimental studies have shown reciprocal relationships between insulin resistance (IR) and endothelial dysfunction. Hypercholesterolemia and hypertension have a synergistic deleterious effect on IR and endothelial dysfunction. Unregulated renin-angiotensin system (RAS) is important in the pathogenesis of atherosclerosis and hypertension. Various strategies with different classes of antihypertensive medications to reach target goals have failed to reduce residual CVD risk further. Of interest, treating moderate cholesterol elevations with low-dose statins in hypertensive patients reduced CVD risk by 35-40% further. Therefore, statins are important in reducing CVD risk. Unfortunately, statin therapy causes IR and increases the risk of type 2 diabetes mellitus. RAS inhibitors improve both endothelial dysfunction and IR. Further, cross-talk between hypercholesterolemia and RAS exists at multiple steps of IR and endothelial dysfunction. In this regard, combined therapy with statins and RAS inhibitors demonstrates additive/synergistic effects on endothelial dysfunction and IR in addition to lowering cholesterol levels and blood pressure when compared with either monotherapy in patients. This is mediated by both distinct and interrelated mechanisms. Therefore, combined therapy with statins and RAS inhibitors may be important in developing optimal management strategies in patients with hypertension, hypercholesterolemia, diabetes, metabolic syndrome, or obesity to prevent CVD.  

Factors involved in rosuvastatin induction of insulin sensitization in rats fed a high fat diet

BACKGROUND AND AIM

To investigate whether rosuvastatin can improve insulin sensitivity in overweight rats having a high fat diet (HFD). The potential mechanisms involved in this action were evaluated, including SIRT-1, other factors involved in glucose metabolism and stress signaling pathways.

METHODS AND RESULTS

Male Wistar rats (n = 30) were divided into three groups: (i) rats fed a standard diet (3.5% fat); (ii) rats fed a HFD (33.5% fat); and (iii) rats fed a HFD and treated with rosuvastatin (15 mg/kg/day). Evolution: 7 weeks. HFD rats showed increased body, epididymal and lumbar adipose tissue weights. Plasma levels of cholesterol, triglycerides, VLDL, glucose and insulin and leptin/adiponectin ratio were higher in HFD rats, and rosuvastatin treatment reduced them. SIRT-1, p53, PGC-1α, PPAR-γ and GLUT-4 protein levels in white adipose tissue (WAT) were lower, and JNK was higher in HFD rats compared to controls. Rosuvastatin treatment normalized expression of these mediators. Endothelium-dependent relaxation was reduced in mesenteric rings from HFD rats compared to controls and rosuvastatin enhanced it in HFD rats.

CONCLUSION

Rosuvastatin treatment reduced insulin resistance without affecting body weight or WAT loss in HFD rats. Reduction of leptin and JNK, and enhancement of SIRT-1, p53, PGC-1α, PPAR-γ and GLUT-4 expression in WAT could contribute to insulin sensitization. Normalization of SIRT-1 expression in WAT could be considered a key novel mechanism that aids in explaining the beneficial effects of rosuvastatin on the amelioration of glucose metabolism and the arrangement of multiple signaling pathways participating in insulin resistance in overweight HFD rats.

Statins and diabetes mellitus: risks and benefits

Patients with diabetes mellitus (DM) are at a high risk of cardiovascular events (CVE). Currently, the predominant clinical strategy of the CVE prevention in DM patients is aggressive lowering of low-density lipoprotein cholesterol and blood pressure levels. In this clinical group, statins are among the most widely used pharmacological agents. Recent clinical evidence suggests that statin therapy could be associated with an increased risk of DM. Both clinicians and researchers need to reevaluate the issue of statin safety in the patients at a higher CVE risk. This review focuses on the problem of DM development in statin-treated patients.

Potentially important considerations in choosing specific statin treatments to reduce overall morbidity and mortality

Hypercholesterolemia and dyslipidemia are independent risk factors for cardiovascular disease and death. Statins are the drugs of choice to decrease plasma cholesterol and have other beneficial actions beyond lipid-lowering leading to substantial improvements in cardiovascular morbidity and mortality. However, evaluation of the effects of statins to reduce overall morbidity and mortality must integrate metabolic consequences of statin therapy with its lipid-lowering effect. Indeed, reduction in LDL-cholesterol to target level achieved by statins does not completely eliminate risk of cardiovascular disease and may elevate metabolic risk factors that contribute to dysregulation of metabolic homeostasis. This may lead to increased incidence of diabetes and its cardiovascular complications that are explained, in part, by reciprocal relationships between insulin resistance and endothelial dysfunction. Genetic factors may determine 40-60% of total cholesterol levels and 70% of the efficacy of statin treatments. Metabolic and cardiovascular phenotypes that are either genetically determined or environmentally acquired are also important determinants of responses to specific statins. Moreover, differences between biological outcomes of specific statins or increasing dosages of statins result in differential metabolic actions due to off-target or unknown mechanism that have important implications for the use of statins to reduce overall morbidity and mortality. In this review, we discuss differential cardiovascular and metabolic pleiotropic actions of specific statins that interact in a context-dependent manner with patient phenotypes and genotypes. These important considerations may influence progression of atherosclerosis, risk of diabetes, and modulation of insulin resistance that help determine overall morbidity and mortality in patients undergoing statin therapy.

Statin intake is associated with decreased insulin sensitivity during cardiac surgery

OBJECTIVE

Surgical trauma impairs intraoperative insulin sensitivity and is associated with postoperative adverse events. Recently, preprocedural statin therapy is recommended for patients with coronary artery disease. However, statin therapy is reported to increase insulin resistance and the risk of new-onset diabetes. Thus, we investigated the association between preoperative statin therapy and intraoperative insulin sensitivity in nondiabetic, dyslipidemic patients undergoing coronary artery bypass grafting.

RESEARCH DESIGN AND METHODS

In this prospective, nonrandomized trial, patients taking lipophilic statins were assigned to the statin group and hypercholesterolemic patients not receiving any statins were allocated to the control group. Insulin sensitivity was assessed by the hyperinsulinemic-normoglycemic clamp technique during surgery. The mean, SD of blood glucose, and the coefficient of variation (CV) after surgery were calculated for each patient. The association between statin use and intraoperative insulin sensitivity was tested by multiple regression analysis.

RESULTS

We studied 120 patients. In both groups, insulin sensitivity gradually decreased during surgery with values being on average ∼20% lower in the statin than in the control group. In the statin group, the mean blood glucose in the intensive care unit was higher than in the control group (153 ± 20 vs. 140 ± 20 mg/dL; P < 0.001). The oscillation of blood glucose was larger in the statin group (SD, P < 0.001; CV, P = 0.001). Multiple regression analysis showed that statin use was independently associated with intraoperative insulin sensitivity (β = -0.16; P = 0.03).

CONCLUSIONS

Preoperative use of lipophilic statins is associated with increased insulin resistance during cardiac surgery in nondiabetic, dyslipidemic patients.

Statin use and the risk of incident diabetes mellitus: a review of the literature

Statins are one of the most widely prescribed medications in the world. They are beneficial in both the primary and secondary prevention of atherosclerotic cardiovascular disease events. In recent years, however, concern has been raised regarding an increased incidence of new-onset diabetes mellitus observed in clinical trials of statin therapy. While most randomized, placebo controlled, statin trials have not included the incidence of new-onset diabetes as a major primary end point, a very small but consistent adverse effect on glycosylated hemoglobin and blood glucose levels, which is presently of unknown clinical significance, has been observed. Importantly, it should be remembered that some patient subgroups exposed to statin therapy, such as those with the metabolic syndrome, may already be particularly vulnerable to developing diabetes mellitus. Experimentally, although the weight of evidence suggests a protective effect of statins on the development of diabetes mellitus, basic science studies have documented conflicting evidence regarding both the beneficial and adverse effects from statin therapy on insulin secretion and sensitivity. In addition, the possibility that statin-induced muscle inflammation may elevate blood glucose levels cannot be excluded. Thus, although the biological plausibility of statins inducing diabetes certainly may exist, at the present time, sufficient high-quality scientific evidence does not exist to definitively establish the veracity or the strength of any putative cause and effect relationship. And without such evidence, there is no current impetus to alter existing clinical practice recommendations regarding the appropriate use of statin therapy.

Opposite effects of pravastatin and atorvastatin on insulin sensitivity in the rat: role of vitamin D metabolites

OBJECTIVE

Recent studies indicate that pravastatin improves whereas other statins impair glucose homeostasis in humans, but the underlying mechanisms are not clear. We examined the effect of pravastatin and atorvastatin on insulin sensitivity in a rat model.

METHODS

Pravastatin (40 mg/kg/day) or atorvastatin (20mg/kg/day) were administered for 3 weeks and insulin sensitivity was assessed by measuring fasting plasma insulin, HOMA-IR, non-esterified fatty acids (NEFA) and glycerol levels, as well as by the hyperinsulinemic euglycemic clamp.

RESULTS

Pravastatin had no effect on fasting insulin and HOMA-IR but significantly reduced plasma NEFA and glycerol levels and increased glucose infusion rate (GIR) during the hyperinsulinemic clamp. Increase in GIR induced by pravastatin was not abolished by NO synthase inhibitor, l-NAME, indicating that this effect did not result from the improvement of endothelial function. Atorvastatin increased fasting insulin, HOM-IR, NEFA and glycerol levels as well as reduced GIR. Statins had no effect on leptin, HMW adiponectin, resistin, visfatin, interleukin-6 and TNF-α. Pravastatin increased plasma concentrations of 25-hydroxy- and 1,25-dyhydroxyvitamin D(3) (25-OH-D(3) and 1,25-(OH)(2)-D(3)), and its effect on insulin sensitivity was mimicked by exogenous 1,25-(OH)(2)-D(3). Atorvastatin reduced plasma 25-OH-D(3) but had no effect on 1,25-(OH)(2)-D(3). Decrease in insulin sensitivity induced by atorvastatin was not corrected by supplementation of vitamin D(3) despite normalization of plasma 25-OH-D(3) level.

CONCLUSIONS

Pravastatin and atorvastatin have opposite effects on insulin sensitivity and vitamin D(3) status. Pravastatin-induced increase in insulin sensitivity is mediated by elevation of 1,25-(OH)(2)-D(3). In contrast, atorvastatin-induced decrease in insulin sensitivity is independent of lowering 25-OH-D(3).

Influence of catch-up growth on islet function and possible mechanisms in rats

OBJECTIVE

The purpose of this study was to examine how catch-up growth modulated islet function and what the detailed mechanisms were, especially at various stages and in different forms, of catch-up growth.

METHODS

We examined the modulation of islet function during catch-up growth by employing an oral glucose tolerance test and gained some insight into the possible mechanisms involved by measuring general physiologic parameters, pancreatic morphometry, insulin content, and the state of chronic oxidative stress. Correlation analyses were used to assess the correlation of insulin/glucose incremental area ratio to other parameters.

RESULTS

The catch-up growth groups resulted in damage to islet function as shown by an increased insulin/glucose incremental area ratio (P ≤ 0.05), smaller relative area of β-cells (P ≤ 0.05), larger relative area of α-cells (P ≤ 0.05), lower insulin content (P ≤ 0.05), increased nitric oxide and malondialdehyde concentrations, and decreased superoxide dismutase concentration (P ≤ 0.05, respectively). With time these changes became increasingly unmarked.

CONCLUSION

Catch-up growth in different stages and forms induces varying degrees of islet dysfunction, possibly by corresponding changes in general physiologic parameters, pancreatic morphometry, insulin content, and the state of chronic oxidative stress.

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.

Pharmacological effects of lipid-lowering drugs on circulating adipokines

The cardioprotective effects of lipid-lowering drugs have been primarily attributed to their effects on blood lipid metabolism. However, emerging evidence indicates that lipid-lowering drugs also modulate the synthesis and secretion of adipose tissue-secreted proteins referred to as adipokines. Adipokines influence energy homeostasis and metabolism and have also been shown to modulate the vascular inflammatory cascade. The purpose of this review will be to examine the reported effects of commonly used lipid-lowering drugs (statins, fibrates, niacin and omega-3-fatty acids) on the circulating concentrations of leptin, adiponectin, tumor necrosis-factor-α (TNF-α), Retinol binding protein 4 (RBP4) and resistin. Overall, the lipid-lowering drugs reviewed have minimal effects on leptin and resistin concentrations.Conversely, circulating adiponectin concentrations are consistently increased by each lipid-lowering drug reviewed with the greatest effects produced by niacin. Studies that have examined the effects of statins, niacin and omega-3-fatty acids on TNF-α demonstrate that these agents have little effect on circulating TNF-α concentrations. Niacin and fibrates appear to lower RBP4 but not resistin concentrations. The results of the available studies suggest that a strong relationship exists between pharmacological reductions in blood lipids and adiponectin that is not obvious for other adipokines reviewed.

Atorvastatin causes insulin resistance and increases ambient glycemia in hypercholesterolemic patients

OBJECTIVES

We investigated whether atorvastatin might decrease insulin sensitivity and increase ambient glycemia in hypercholesterolemic patients.

BACKGROUND

Clinical trials suggest that some statin treatments might increase the incidence of diabetes despite reductions in low-density lipoprotein (LDL) cholesterol and improvement in endothelial dysfunction.

METHODS

A randomized, single-blind, placebo-controlled parallel study was conducted in 44 patients taking placebo and in 42, 44, 43, and 40 patients given daily atorvastatin 10, 20, 40, and 80 mg, respectively, during a 2-month treatment period.

RESULTS

Atorvastatin 10, 20, 40, and 80 mg significantly reduced LDL cholesterol (39%, 47%, 52%, and 56%, respectively) and apolipoprotein B levels (33%, 37%, 42%, and 46%, respectively) after 2 months of therapy when compared with either baseline (all p < 0.001 by paired t test) or placebo (p < 0.001 by analysis of variance [ANOVA]). Atorvastatin 10, 20, 40, and 80 mg significantly increased fasting plasma insulin (mean changes: 25%, 42%, 31%, and 45%, respectively) and glycated hemoglobin levels (2%, 5%, 5%, and 5%, respectively) when compared with either baseline (all p < 0.05 by paired t test) or placebo (p = 0.009 for insulin and p = 0.008 for glycated hemoglobin by ANOVA). Atorvastatin 10, 20, 40, and 80 mg decreased insulin sensitivity (1%, 3%, 3%, and 4%, respectively) when compared with either baseline (p = 0.312, p = 0.008, p < 0.001, and p = 0.008, respectively, by paired t test) or placebo (p = 0.033 by ANOVA).

CONCLUSIONS

Despite beneficial reductions in LDL cholesterol and apolipoprotein B, atorvastatin treatment resulted in significant increases in fasting insulin and glycated hemoglobin levels consistent with insulin resistance and increased ambient glycemia in hypercholesterolemic patients. (Effects of Atorvastatin on Adiponectin Levels and Insulin Sensitivity In Hypercholesterolemic Patients; NCT00745836).

Statin therapy and risk of developing type 2 diabetes: a meta-analysis

OBJECTIVE

Although statin therapy reduces cardiovascular risk, its relationship with the development of diabetes is controversial. The first study (West of Scotland Coronary Prevention Study [WOSCOPS]) that evaluated this association reported a small protective effect but used nonstandardized criteria for diabetes diagnosis. However, results from subsequent hypothesis-testing trials have been inconsistent. The aim of this meta-analysis is to evaluate the possible effect of statin therapy on incident diabetes.

RESEARCH DESIGN AND METHODS

A systematic literature search for randomized statin trials that reported data on diabetes through February 2009 was conducted using specific search terms. In addition to the hypothesis-generating data from WOSCOPS, hypothesis-testing data were available from the Heart Protection Study (HPS), the Long-Term Intervention with Pravastatin in Ischemic Disease (LIPID) Study, the Anglo-Scandinavian Cardiac Outcomes Trial (ASCOT), the Justification for the Use of Statins in Prevention: an Intervention Trial Evaluating Rosuvastatin (JUPITER), and the Controlled Rosuvastatin Multinational Study in Heart Failure (CORONA), together including 57,593 patients with mean follow-up of 3.9 years during which 2,082 incident diabetes cases accrued. Weighted averages were reported as risk ratios (RRs) with 95% CIs using a random-effects model. Statistical heterogeneity scores were assessed with the Q and I(2) statistic.

RESULTS

In the meta-analysis of the hypothesis-testing trials, we observed a small increase in diabetes risk (RR 1.13 [95% CI 1.03-1.23]) with no evidence of heterogeneity across trials. However, this estimate was attenuated and no longer significant when the hypothesis-generating trial WOSCOPS was included (1.06 [0.93-1.25]) and also resulted in significant heterogeneity (Q 11.8 [5 d.f.], P = 0.03, I(2) = 57.7%).

CONCLUSIONS

Although statin therapy greatly lowers vascular risk, including among those with and at risk for diabetes, the relationship of statin therapy to incident diabetes remains uncertain. Future statin trials should be designed to formally address this issue.

Antiatherosclerotic and anti-insulin resistance effects of adiponectin: basic and clinical studies

Adiponectin is a protein secreted by adipose cells that may couple regulation of insulin sensitivity with energy metabolism and serve to link obesity with insulin resistance. Obesity-related disorders characterized by insulin resistance including the metabolic syndrome, diabetes, atherosclerosis, hypertension, and coronary artery disease are associated with both decreased adiponectin levels and endothelial dysfunction. Recent studies demonstrate that adiponectin has insulin-sensitizing effects as well as antiatherogenic properties. Lifestyle modifications and some drug therapies to treat atherosclerosis, hypertension, diabetes, and coronary heart disease have important effects in increasing adiponectin levels, decreasing insulin resistance, and improving endothelial dysfunction. In this review, we discuss insights into the relationships between adiponectin levels, insulin resistance, and endothelial dysfunction that are derived from various therapeutic interventions. The effects of lifestyle modifications and cardiovascular drugs on adiponectin levels and insulin resistance suggest plausible mechanisms that may be important for understanding and treating atherosclerosis and coronary heart disease.

Differential metabolic effects of pravastatin and simvastatin in hypercholesterolemic patients

BACKGROUND

Lipophilic and hydrophilic statins have different effects on adiponectin and insulin resistance in experimental studies and different effects on the rate of onset of new diabetes in large scale clinical studies. Therefore, we hypothesized that simvastatin and pravastatin may have differential metabolic effects in hypercholesterolemic patients.

METHODS

This was a randomized, single-blind, placebo-controlled, parallel study. Age, gender, and body mass index were matched. Forty-three patients were given placebo, simvastatin 20mg, or pravastatin 40 mg, respectively once daily for 2 months.

RESULTS

Simvastatin and pravastatin therapy significantly changed lipoprotein levels and improved flow-mediated dilation after 2 months when compared with baseline (P<0.001) or placebo treatment (P<0.001 by ANOVA). Simvastatin therapy significantly increased insulin levels (mean % changes; 127%, P=0.014) and decreased plasma adiponectin levels (10%, P=0.012) and insulin sensitivity as assessed by QUICKI (6%, P=0.007) when compared with baseline. By contrast, pravastatin therapy did not significantly change insulin levels (-3%, P=0.437) but significantly increased plasma adiponectin levels (9%, P=0.011) and insulin sensitivity (6%, P=0.008) when compared with baseline. In addition, these effects of simvastatin were significant when compared with pravastatin (P<0.001 for insulin levels by ANOVA on Ranks, P<0.001 for adiponectin and P=0.001 for QUICKI by ANOVA). When compared with baseline, simvastatin significantly increased plasma leptin levels (35%, P=0.028), but pravastatin did not (1%, P=0.822).

CONCLUSIONS

Despite causing comparable changes in lipoprotein and endothelium-dependent dilation, simvastatin and pravastatin therapy had differential metabolic effects in hypercholesterolemic patients that may be clinically relevant.