Comparative effects of diet and simvastatin on markers of thrombogenicity in patients with coronary artery disease

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.

Beneficial effects of cardiac rehabilitation and exercise after percutaneous coronary intervention on hsCRP and inflammatory cytokines in CAD patients

Recent studies showed that tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6), as well as high-sensitive C-reactive protein (hsCRP) levels are predictive factors of cardiovascular risk. However, the effect of cardiac rehabilitation (CR) intervention in coronary artery disease (CAD) patients on these factors is not known. The aim of this study was to evaluate the effects of CR and exercise on hsCRP and inflammatory cytokine levels in patients with CAD after percutaneous coronary intervention (PCI). CAD patients who underwent PCI were divided into a CR and exercise group (CRE, n = 29) or a control group (CON, n = 10). CR and exercise consisted of 6 weeks supervised exercise training and 8 weeks home-based, self-managed exercise. Compared to pre-experimental levels, TNF-alpha (by 20.4%; p = 0.006) and IL-6 (by 49.0%; p < 0.0001), as well as hsCRP (by 59.4%; p < 0.0001), were markedly decreased after CR and exercise in CAD patients but not in control group, except for IL-6 (by 41.6%; p = 0.001). However, there was no significant alteration of adiposity-related variables such as BMI, percent body fat, and waist circumferences, in both groups. We suggest that CR and exercise in CAD patients after PCI induce significant reduction in hsCRP and inflammatory cytokines (TNF-alpha and IL-6), and marked increase in exercise tolerance and capacity.

Inflammatory process in type 2 diabetes: The role of cytokines

Population-based studies have shown strong relationship between inflammatory markers and metabolic disturbances, obesity, and atherosclerosis, whereas inflammation has been considered as a "common soil" between these clinical entities and type 2 diabetes (T2D). The accumulation of macrophages in adipose tissue (AT), the common origin of macrophages and adipocytes, the prevalent presence of peripheral mononuclear cells, and apoptotic beta cells by themselves seem to be the sources of inflammation present in T2D, since they generate the mediators of the inflammatory processes, namely cytokines. The main cytokines involved in the pathogenesis of T2D are interleukin-1beta (IL-1beta), with an action similar to the one present in type 1 diabetes, tumor necrosis factor-alpha (TNF-alpha), and IL-6, considered as the main regulators of inflammation, leptin, more recently introduced, and several others, such as monocyte chemoattractant protein-1, resistin, adiponectin, with either deleterious or beneficial effects in diabetic pathogenesis. The characterization of these molecules targeted diabetes treatment beyond the classical interventions with lifestyle changes and pharmaceutical agents, and toward the determination of specific molecular pathways that lead to low grade chronic inflammatory state mainly due to an immune system's unbalance.

Combined therapy with ramipril and simvastatin has beneficial additive effects on tissue factor activity and prothrombin fragment 1+2 in patients with type 2 diabetes

Tissue factor (TF) plays a pivotal role in thrombus formation. Statins and angiotensin converting enzyme inhibitors attenuate expression of TF by distinct mechanism. Therefore, we hypothesized that combined therapy with simvastatin and ramipril may have additive beneficial anti-atherogenic effects to lower TF activity when compared with either drug alone. This was a randomized, double-blind, placebo-controlled cross-over trial with three treatment arms (each 2 months) and two washout periods (each 2 months). Fifty patients with type 2 diabetes were given simvastatin 20 mg and placebo, simvastatin 20 mg and ramipril 10 mg, or ramipril 10 mg and placebo daily during each treatment period. Simvastatin and ramipril monotherapy tended to reduce TF activity (0.53 to 0.46 nM, P=0.056; 0.54 to 0.50 nM, P=0.167, respectively) while combined therapy had a significant effect (0.64 to 0.43 nM, P<0.001). All three therapies significantly reduced prothrombin fragment 1+2 (F1+2) levels from their respective baselines (P=0.037, P<0.001, and P=0.057, respectively). Combined therapy significantly reduced TF activity and F1+2 levels to a greater extent than either simvastatin or ramipril alone (P=0.029 and P=0.040 by ANOVA, respectively). Percent changes in TF activity and percent changes in F1+2 levels were significantly correlated. All three therapies reduced CD40 ligand levels from their respective baselines (P=0.098, P<0.001, and P=0.002, respectively) with no significant differences among these three therapies (P=0.204 by ANOVA). Ramipril combined with simvastatin significantly reduces plasma TF activity and F1+2 levels to a greater extent than monotherapy with either drug in patients with type 2 diabetes.

Impact of simvastatin on hemostatic and fibrinolytic regulators in Type 2 diabetes mellitus

Simvastatin, a widely used 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) reductase inhibitor, effectively reduced cardiac death and ischemic events in patients with coronary heart disease (CHD) and diabetes mellitus (DM). The mechanism of cardiovascular benefits of statins in DM remains unclear. We examined how simvastatin influences the levels of several in vivo markers for coagulation and fibrinolysis in 26 Type 2 DM patients. The diabetic patients received 20 mg/day of simvastatin up to 12 months. The levels of total cholesterol (TC), low density lipoprotein-cholesterol (LDL-c) and triglycerides in peripheral circulation of patients were significantly reduced after > or =6 weeks of simvastatin treatment. Levels of prothrombin fragment 1+2 (F1+2), factor VII, plasminogen activator inhibitor-1 (PAI-1) and tissue factor pathway inhibitor (TFPI) antigens, but not tissue plasminogen activator (tPA) antigen, in the pre-simvastatin plasmas of the diabetic patients were significantly higher than the levels found in plasmas of healthy subjects. Significant reductions in F1+2 and PAI-1 levels were evident > or =6 weeks after the diabetic patients received simvastatin. Levels of total tPA, TFPI, FVII, hemoglobin A1c, fasting blood glucose, and insulin in the diabetic patients' plasma were not significantly altered by simvastatin treatment. Positive correlations were found between PAI-1 versus TC, PAI-1 versus LDL-c, and FVII versus triglycerides in the plasmas of simvastatin-treated patients. The results suggest that simvastatin reduces in vivo prothrombinase activity and PAI-1 levels in type 2 DM patients. These actions may contribute to the protective properties of simvastatin against ischemic events in diabetic patients.