HMG-CoA reductase inhibitors: Is the endothelium the main target?

Impact of atorvastatin on erectile dysfunction: A meta-analysis and systematic review

Atorvastatin may be an effective treatment for erectile dysfunction (ED). The purpose of this meta-analysis was to determine whether atorvastatin therapy is effective in the treatment of ED. All published research on atorvastatin in the treatment of ED patients in EMBASE, PubMed, Web of Science and Cochrane were investigated till 30 October 2021. A meta-analysis of randomized controlled trials (RCTs) was done to investigate the efficacy of atorvastatin and placebo in the treatment of ED. Moreover, we also performed a meta-analysis based on single-arm trials (SATs) to explore the atorvastatin treatment on the efficacy of ED. In a meta-analysis based on RCTs, the weighted mean difference of the change of International Index for Erectile Function-5 (IIEF-5) score in the atorvastatin treatment group with or without treatment was 4.53 (95 per cent confidence interval [CI] of 3.28-5.79) higher than in the control group. In an SAT-based meta-analysis, the ES of the change in IIEF-5 score in the atorvastatin treatment group before and after treatment was 3.22 (95 per cent CI of 1.32-5.12). Atorvastatin is an effective therapeutic drug for patients with ED. However, we expect that more multicentre clinical trials will be conducted to support this assertion.

Effects of atorvastatin and insulin in vascular dysfunction associated with type 2 diabetes

Atorvastatin and insulin have distinct mechanisms of action to improve endothelial function. Therefore, we hypothesized that atorvastatin and insulin therapies alone or in combination could have beneficial effects on endothelium-dependent vascular reactivity, oxidative stress, inflammation and metabolic parameters in Goto-Kakizaki (GK) rats, a model of type 2 diabetes fed with atherogenic diet (GKAD). In parallel with the development of diabetes and lipid profile, the generation of oxidative stress was determined by measurement of lipid peroxides and oxidized proteins and the presence of inflammation was evaluated by assessing C-reactive protein (CRP). Additionally, endothelial dependent and independent vascular sensitivity to acetylcholine and sodium nitroprusside were evaluated. GKAD showed increased carbonyl stress, inflammation, fasting glycemia, dyslipidemia and endothelial dysfunction when compared to control GK rats. Noteworthy, supplementation with insulin deteriorated endothelial dysfunction while atorvastatin induced an improvement. Atorvastatin and insulin therapies in combination improved metabolic parameters, CRP levels and insulin resistance indexes and ameliorated endothelial dysfunction in GKAD rats while they were unable to reduce urinary 8-isoprostranes and plasma carbonyl compounds. The therapeutic association of atorvastatin and insulin provided a better metabolic control with a reduction in endothelial dysfunction in GKAD rats by a mechanism that involves an improvement in systemic inflammation.

In vivo and in vitro anti-inflammatory and anti-nociceptive activities of lovastatin in rodents

Statins are among the most prescribed drugs in recent clinical practice. They are also known for their pleiotropic actions, which are independent of their lipid-lowering properties. The effect of lovastatin was investigated against carrageenan-induced paw edema in male Wistar rats (200-250 g) and on leukocyte migration, as measured by carrageenan-induced peritonitis in male Swiss mice (20-25 g), which are models of acute inflammation. Lovastatin (administered 1 h prior to carrageenan), at oral doses of 2, 5, and 10 mg/kg, markedly attenuated paw edema formation in rats at the 4th hour after carrageenan injection (25, 43, and 37% inhibition, respectively). Inhibitions of 20, 45 and 80% were observed in the leukocyte migration, as evaluated by carrageenan-induced peritonitis in mice with lovastatin doses of 0.5, 1 and 5 mg/kg, as compared to controls. Furthermore, lovastatin (administered 1 h before initiation) reduced the nociceptive effect of the formalin test in mice, at both phases, at doses of 2, 5, and 10 mg/kg: first phase (51, 65, and 70%, respectively) and second phase (73, 57, and 66% inhibition of licking time, respectively). The anti-nociceptive activity of lovastatin was inhibited by naloxone (3 mg/kg, sc). Lovastatin (0.01, 0.1, and 1 µg/mL) inhibited by 23, 79, and 86%, respectively, the release of myeloperoxidase from human neutrophils. Leukocyte (predominantly neutrophils) infiltration was almost completely reduced by lovastatin treatment, as observed in the model of acute paw edema with hematoxylin and eosin staining. In addition, lovastatin decreased the number of cells expressing tumor necrosis factor-α (TNF-α) and the inducible form of nitric oxide synthase (iNOS) activity. Therefore, the alterations in leukocyte activity and cytokine release could contribute to the anti-inflammatory activity of lovastatin.

Comparison of efficacy and adverse effect profile of high dose versus standard dose atorvastatin in acute ST elevation myocardial infarction patients

OBJECTIVE

To compare the efficacy and adverse effects of high and standard dose atorvastatin in ST elevation myocardial infarction (STEMI) patients.

DESIGN

A prospective, single-centre, randomised, double blind study.

SETTING

A tertiary care centre in Kerala, India, from January to June 2009.

PATIENTS

121 consecutive acute STEMI patients eligible for thrombolytic therapy.

INTERVENTIONS

Pharmacological thrombolysis and atorvastatin therapy.

MAIN OUTCOME MEASURES

Primary end points were mean change in low density lipoprotein and total cholesterol, serum glutamic pyruvic transaminase (SGPT), creatine phosphokinase (CPK) at 3 months of high dose (80 mg) and standard dose (20 mg) of atorvastatin.

RESULTS

There was no significant difference in the mean cholesterol levels at 3 months of therapy (mean reduction in total cholesterol and low density lipoprotein cholesterol were 48 mg%, 49 mg% in the 20 mg group compared with 54 mg% and 53 mg%, respectively, in the 80 mg group; p 0.39 and 0.4). There was a significant increase in SGPT at 1 week in the 80 mg group and atorvastatin was stopped in a significantly higher number of patients due to the increase in SGPT and CPK at 1 week in the high dose group (12% and 7% of patients; (p=0.04 and p=0.06, respectively).

CONCLUSION

In acute STEMI patients treated with pharmacological thrombolysis, standard dose atorvastatin is equally effective as high dose atorvastatin in terms of reduction in cholesterol, with higher and earlier incidence of asymptomatic SGPT and CPK elevation in the high dose group.

Effect of statin therapy on early return of potency after nerve sparing radical retropubic prostatectomy

PURPOSE

We prospectively investigated whether postoperative statin use would contribute to earlier recovery of erectile function in men who underwent bilateral nerve sparing radical retropubic prostatectomy for clinically localized prostate cancer.

MATERIALS AND METHODS

A total of 50 potent men without hypercholesterolemia undergoing bilateral nerve sparing radical retropubic prostatectomy for clinically localized prostate cancer were prospectively randomized into 2 equal groups. Group 1 patients were instructed to ingest only 50 mg sildenafil per day if needed following hospital discharge after radical retropubic prostatectomy. Group 2 patients were prescribed atorvastatin at a dose of 10 mg daily from postoperative days 1 to 90 and they were also instructed to ingest sildenafil, as in group 1. Patient status regarding potency and adverse events were assessed 6 months after surgery.

RESULTS

The 2 groups demonstrated no significant differences regarding various baseline factors, including International Index of Erectile Function-5 scores. Group 2 had a significantly higher postoperative International Index of Erectile Function-5 score than group 1 at 6 months postoperatively (p = 0.003). Meanwhile, as judged by a preset definition, the incidence of potent patients 6 months after prostatectomy was 26.1% in group 1 and 55% in group 2 (p = 0.068). Also, 17.4% and 40% of the men reported achieving intercourse by vaginal penetration without a phosphodiesterase 5 inhibitor in groups 1 and 2, respectively (p = 0.172). No serious adverse events associated with medication were reported.

CONCLUSIONS

Postoperative treatment with atorvastatin in men who report normal erectile function preoperatively may contribute to earlier recovery of erectile function after nerve sparing radical retropubic prostatectomy.

Simvastatin inhibits NF-kappaB signaling in intestinal epithelial cells and ameliorates acute murine colitis

Statins, HMG-CoA reductase inhibitors exert pleiotropic anti-inflammatory properties in vitro and in vivo, and are associated with the risk reduction of colorectal cancer. It remains unknown, however, whether statin is effective for the treatment of inflammatory bowel disease (IBD). Therefore, we investigated anti-inflammatory effects of simvastatin on intestinal epithelial cells (IEC) and on an experimental murine colitis model, and elucidated its molecular mechanisms. Simvastatin (50 micro M) significantly inhibited TNF-alpha-induced IL-8 gene expression in COLO 205 cells. Simvastatin (50 micro M) blocked TNF-alpha-induced NF-kappaB transcriptional activity, IkappaB phosphorylation/degradation and DNA binding activity of NF-kappaB. Administration of simvastatin significantly reduced the severity of dextran sulfate sodium (DSS)-induced murine colitis as assessed by body weight, colon length, DAI, and histology in a dose-dependent manner. These results suggest that simvastatin inhibits proinflammatory gene expression by blocking NF-kappaB signaling in IEC, and attenuates DSS-induced acute murine colitis. Simvastatin could be a potential agent for the treatment of IBD.

The effect of rapid lipid lowering with atorvastatin on autonomic parameters in patients with coronary artery disease

Many cardiovascular disease states are associated with autonomic dysfunction, specifically sympathetic activation and parasympathetic withdrawal. Both these autonomic derangements are independently associated with adverse prognostic outcomes. HMG CoA reductase inhibitors (statins) reduce cardiovascular mortality and morbidity when compared to placebo in subjects with proven coronary artery disease (CAD), including sudden presumed arrhythmic death. As autonomic dysfunction is associated with arrhythmogenesis, statins may be having a beneficial effect on autonomic function in these subjects. We conducted a randomised, double-blind, placebo-controlled, cross-over study examining the effect of rapid short-term lipid lowering with a statin on autonomic function in CAD patients. Ten subjects with proven CAD (8 male, 2 female; mean age 63.4 years) were randomised to receive either 80 mg atorvastatin or placebo over a 4 week period followed by a 4 week washout, then the alternative treatment for a further 4 weeks. Autonomic parameters assessed were plasma noradrenaline levels on recumbency and 80 degrees head-up tilt, cold pressor testing, and heart rate variability (HRV) analysis. Plasma noradrenaline levels were significantly reduced (p=0.050) after 20 min rest in the recumbent position, with atorvastatin compared to placebo. A nonsignificant reduction in plasma noradrenaline with atorvastatin compared to placebo was observed in the prolonged 80 degrees head-up position (p=0.207). In addition, sympathovagal balance was shifted to greater vagal predominance with atorvastatin (low-frequency/high-frequency ratio in the HRV frequency domain) when compared to placebo, p=0.06. We found that rapid lipid lowering with atorvastatin reduces sympathetic nervous system in this pilot study of CAD patients. Larger trials are required to definitively address the effects of statins on autonomic activity in these patients.

Effects of statins beyond lipid lowering: Potential for clinical benefits

BACKGROUND

The role of statin drugs in the reduction of serum lipids has been well documented. More recently, evidence suggesting that statins may positively impact many organ systems and disease states independent of lipid reduction has emerged. The term "pleiotropic effects" has been used to refer to these properties. We reviewed the evidence exploring such potential effects.

METHODS

A search of the MEDLINE database was conducted for articles published between 1985 to 2005 on the pleiotropic and the lipid-lowering independent effects of statin drugs. The search terms "statin", "HMG-CoA reductase inhibitor", "pleiotropic effects", and "inflammation" were used. English language articles were selected for inclusion along with selected cross-references.

RESULTS

Numerous animal and clinical studies support the presence of a spectrum of beneficial effects for statins that are independent of their lipid-lowering properties. These effects are mediated by a variety of mechanisms and they suggest that the therapeutic role of statins may expand.

CONCLUSION

Statins have shown great promise beyond their lipid-lowering effects. Ongoing and future studies will help to further clarify the potential clinical impact of these "pleiotropic effects".

Molecular aspects of atherogenesis: new insights and unsolved questions

The development of atherosclerotic disease results from the interaction between environment and genetic make up. A key factor in atherogenesis is the oxidative modification of lipids, which is involved in the recruitment of mononuclear leukocytes to the arterial intima--a process regulated by several groups of adhesion molecules and cytokines. Activated leukocytes, as well as endothelial mitochondria, can produce reactive oxygen species (ROS) that are associated with endothelial dysfunction, a cause of reduced nitric oxide (NO) bioactivity and further ROS production. Peroxisome proliferator-activated receptors (PPAR) and liver X receptors (LXR) are nuclear receptors significantly involved in the control of lipid metabolism, inflammation and insulin sensitivity. Also, an emerging role has been suggested for G protein coupled receptors and for the small Ras and Rho GTPases in the regulation of the expression of endothelial NO synthase (eNOS) and of tissue factor, which are involved in thrombus formation and modulation of vascular tone. Further, the interactions among eNOS, cholesterol, oxidated LDL and caveola membranes are probably involved in some molecular changes observed in vascular diseases. Despite the relevance of oxidative processes in atherogenesis, anti-oxidants have failed to significantly improve atherosclerosis (ATS) prevention, while statins have proved to be the most successful drugs.

IMPROVEMENT IN ERECTILE FUNCTION IN MEN WITH ORGANIC ERECTILE DYSFUNCTION BY CORRECTION OF ELEVATED CHOLESTEROL LEVELS: A CLINICAL OBSERVATION

PURPOSE

We determined that use of a statin drug to lower cholesterol would improve erectile function in men who have hypercholesterolemia as the only risk factor for erectile dysfunction (ED).

MATERIALS AND METHODS

A total of 18 men were determined to have increased cholesterol as the only risk factor for ED by history, system review, physical examination and laboratory analysis. Nine of these men agreed to participate in the study. Organic ED was verified by abnormal nocturnal penile tumescence and rigidity testing with the RigiScan (UroHealth Systems, Inc., Laguna Niguel, California) and Sexual Health Inventory in Men questionnaire. Subjects were given atorvastatin with a goal decrease of total cholesterol to less than 200 mg/dl and low-density lipoprotein cholesterol to less than 120 mg/dl. RigiScan measurements were compared before and after treatment with atrovastatin.

RESULTS

Mean age +/- SD was 49.7 +/- 7.4 years. Mean length of treatment with atrorvastatin was 3.7 +/- 2.1 months. Clinically 8 of the 9 men had improved erection adequate for penetration during sexual intercourse. Mean questionnaire scores improved from 14.2 to 20.7 (p <0.001). Mean total and low-density lipoprotein cholesterol decreased significantly after treatment (p <0.001). RigiScan measurements showed an increased average penile rigidity at the base (p <0.001) and tip (p <0.005) after treatment with atorvastatin.

CONCLUSIONS

Erectile function improves in men with hypercholesterolemia as the only risk factor for ED when treated with atorvastatin. Treating hypercholesterolemia may improve ED, while promoting primary cardiac prevention.

Simvastatin normalizes autonomic neural control in experimental heart failure

BACKGROUND

HMG-CoA reductase inhibitors (statins) have been shown to beneficially affect outcomes in chronic heart failure (CHF). We hypothesized that statins exert effects on autonomic function, as assessed by plasma norepinephrine levels, direct recordings of renal sympathetic nerve activity (RSNA), and baroreflex function.

METHODS AND RESULTS

Normolipidemic CHF rabbits were treated with simvastatin or vehicle. CHF was induced by continuous ventricular pacing at 320 to 340 bpm for 3 weeks. Two to 3 days after instrumentation of the rabbits with renal nerve electrodes and arterial and venous catheters, blood samples and RSNA recordings were obtained in the conscious state. Baroreflex function was assessed after administration of sodium nitroprusside and phenylephrine. Mean baseline RSNA (+/-SEM) in normal rabbits was 19.3+/-3.8%; in CHF rabbits, 39.4+/-2.9% (P<0.05); in CHF rabbits on low-dose (0.3 mg x kg(-1) x d(-1)) simvastatin, 39.8+/-8.3% (P<0.05); and in CHF rabbits on high-dose simvastatin (3 mg x kg(-1) x d(-1)), 21.1+/-4.5% (P=NS). Similar data were observed for plasma norepinephrine. In CHF rabbits treated with 3 mg x kg(-1) x d(-1) simvastatin, baroreflex regulation of heart rate to transient hypotension with sodium nitroprusside was normalized by 66% compared with CHF controls.

CONCLUSIONS

These are the first data showing that non-lipid-lowering statin effects include a normalization of sympathetic outflow and reflex regulation in CHF. The precise neural and cellular pathways involved in these responses need further clarification. This finding may have important implications for the treatment of CHF and progression of the disease process.

The 3-hydroxy-3-methylglutaryl-CoA reductase inhibitor pravastatin reduces disease activity and inflammation in dextran-sulfate induced colitis

The dextran sulfate (DSS) model of colitis causes intestinal injury sharing many characteristics with inflammatory bowel disease, e.g., leukocyte infiltration, loss of gut epithelial barrier, and cachexia. These symptoms are partly mediated by entrapped leukocytes binding to multiple endothelial adhesion molecules (MAdCAM-1, VCAM-1, ICAM-1, and E-selectin). Pravastatin, an 3-hydroxy-3-methylglutaryl (HMG)-CoA reductase inhibitor, has anti-inflammatory potency in certain inflammation models; therefore, in this study, we measured the effects of pravastatin in DSS-induced colitis. The administration of pravastatin (1 mg/kg) relieved DSS-induced cachexia, hematochezia, and intestinal epithelial permeability, with no effect on serum cholesterol. Histopathologically, pravastatin prevented leukocyte infiltration and gut injury. Pravastatin also blocked the mucosal expression of MAdCAM-1. DSS treatment promoted mucosal endothelial nitric-oxide synthase (eNOS) mRNA degradation, an effect that was blocked by pravastatin. Importantly, the protective effects of pravastatin in DSS-induced colitis were not found in eNOS-deficient mice. Our results demonstrate that HMG-CoA reductase inhibitors preserve intestinal integrity in colitis, most likely via increased eNOS expression and activity, independent of cholesterol metabolism.

Statins and the role of nitric oxide in chronic heart failure

Endothelial dysfunction plays an important role in a number of cardiovascular diseases. An important pathogenetic factor for the development of endothelial dysfunction is lack of nitric oxide (NO), which is a potent endothelium-derived vasodilating substance. 3-Hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors (statins), originally designed to lower plasma cholesterol levels, seem to ameliorate endothelial dysfunction by a mechanism so far only partly understood. However, statins increase nitric oxide synthase activity. It has been speculated that this and other "side effects" of statin treatment are due to inhibition of Rho, an intracellular signalling protein that initiates Rho kinase transcription. Moreover, statins possess anti-inflammatory characteristics. Some statins have proven to lower plasma levels of C-reactive protein, which is induced by pro-inflammatory cytokines. Other statins have been demonstrated to directly inhibit pro-inflammatory cytokine induction. Finally, some data suggest that statins might be able to counterbalance an increased production of oxygen free radicals. Since chronic heart failure is accompanied not only by endothelial dysfunction, but also by pro-inflammatory cytokine activation and enhanced formation of oxygen free radicals, it is tempting to speculate that statins might be an ideal candidate to treat certain features of this disease. The doses needed to achieve the desired effects might be much lower than those needed to treat hypercholesterolemia.