Effects of simvastatin on cardiohemodynamic responses to ischemia–reperfusion in isolated rat hearts

Atorvastatin reduces β-Adrenergic dysfunction in rats with diabetic cardiomyopathy

Background

In the diabetic heart the β-adrenergic response is altered partly by down-regulation of the β1-adrenoceptor, reducing its positive inotropic effect and up-regulation of the β3-adrenoceptor, increasing its negative inotropic effect. Statins have clinical benefits on morbidity and mortality in diabetic patients which are attributed to their “pleiotropic” effects. The objective of our study was to investigate the role of statin treatment on β-adrenergic dysfunction in diabetic rat cardiomyocytes.

Methods

β-adrenergic responses were investigated in vivo (echocardiography) and ex vivo (left ventricular papillary muscles) in healthy and streptozotocin-induced diabetic rats, who were pre-treated or not by oral atorvastatin over 15 days (50 mg.kg^-1.day^-1). Micro-array analysis and immunoblotting were performed in left ventricular homogenates. Data are presented as mean percentage of baseline ± SD.

Results

Atorvastatin restored the impaired positive inotropic effect of β-adrenergic stimulation in diabetic hearts compared with healthy hearts both in vivo and ex vivo but did not suppress the diastolic dysfunction of diabetes. Atorvastatin changed the RNA expression of 9 genes in the β-adrenergic pathway and corrected the protein expression of β1-adrenoceptor and β1/β3-adrenoceptor ratio, and multidrug resistance protein 4 (MRP4). Nitric oxide synthase (NOS) inhibition abolished the beneficial effects of atorvastatin on the β-adrenoceptor response.

Conclusions

Atorvastatin restored the positive inotropic effect of the β-adrenoceptor stimulation in diabetic cardiomyopathy. This effect is mediated by multiple modifications in expression of proteins in the β-adrenergic signaling pathway, particularly through the NOS pathway.

Cardioprotective potential of simvastatin in the hyperhomocysteinemic rat heart

The present study investigated the probable role of simvastatin, 3-hydroxymethyl-glutaryl coenzyme A (HMG-CoA) reductase inhibitor, in abrogated cardioprotection in hyperhomocysteinemic (Hhcy) rat hearts. Isolated Langendorff's perfused normal and Hhcy rat hearts were subjected to 30-min global ischemia (I) followed by 120-min reperfusion (R). Assessment of myocardial damage was done by measuring infarct size and analyzing the release of lactate dehydrogenase (LDH) and creatine kinase (CK-MB) in coronary effluent. In addition, the oxidative stress in the heart was assessed by measuring lipid peroxidation and superoxide anion generation. I/R produced myocardial injury in normal and Hhcy rat hearts by increasing myocardial infarct size, LDH and CK in coronary effluent and oxidative stress. Hhcy rat hearts showed enhanced myocardial injury and high oxidative stress as compared to normal hearts. Treatment with Simvastatin (10 μMol) afforded cardioprotection against I/R-induced myocardial injury in normal and hyperhomocysteinemic rat hearts as assessed in terms of reductions in myocardial infarct size, LDH and CK levels in coronary effluent and oxidative stress. The reductions in the high degree of oxidative stress may be responsible for the observed cardioprotection afforded by simvastatin against I/R-induced myocardial injury in normal and hyperhomocysteinemic rat hearts.

Interference in mevalonate pathway ameliorates homocysteine-induced endothelium-dysfunction

Homocysteine is a risk factor for atherosclerosis and hypertension and induces endothelium-dysfunction. Accumulation of cholesterol and reactive oxygen species plays a key role in the endothelium-dysfunction. This study investigated the hypothesis of an involvement of mevalonate pathway and oxidative pathway in homocysteine-induced endothelial damage. Homocysteine induced impairment of the endothelium-dependent vasorelaxation of rat aortic rings by isometric tension, while it also reduced the nitric oxide level and the nitric oxide synthase activity in human umbilical vein endothelial cells, followed by accumulation of superoxide anion and cholesterol. However, the level of asymmetric dimethylarginine remained unaffected by homocysteine. The adverse effect of homocysteine on endothelial function was found to be partially enhanced either by squalestatin-reducing cholesterol or by superoxide dismutase-reducing superoxide anion. Moreover, this effect of homocysteine could be completely ameliorated by simvastatin, very similar to that of cotreatment of squalestatin and superoxide dismutase. Respectively, mevalonolactone partly or squalene fully attenuated the effect of simvastatin or squalestatin on homocysteine-induced endothelial dysfunction. In conclusion, our results suggested that the mevalonate pathway mediates homocysteine-induced endothelium dysfunction besides the oxidative pathway. Interference in the mevalonate pathway and oxidative pathway provides effective protection of endothelial function.

Simvastatin reduces mortality and hepatic injury after hemorrhage/resuscitation in rats

Statins are established in the prevention and therapy of chronic cardiovascular diseases because of inhibition of HMG-CoA (3-hydroxy-3-methylglutaryl-coenzyme A), thus lowering blood cholesterol levels. However, their cholesterol-independent effects include regulation of Rho/Rho-kinases (ROCK) and eNOS, proteins centrally involved in various models of acute inflammation. Therefore, we tested the hypothesis that simvastatin confers protection after rat hemorrhage/resuscitation (H/R) and wanted to elucidate the mechanisms involved. Fifty-two female Lewis rats (180-250 g) were pretreated with simvastatin 5 mg/kg per day or vehicle for 6 days (i.p.). Then, rats were hemorrhaged to a mean arterial pressure of 30 +/- 2 mmHg for 60 min and resuscitated. Control group underwent surgical procedures without H/R. Two hours after resuscitation, tissues were harvested. Mortality was assessed 72 h after H/R. Simvastatin pretreatment increased survival after H/R from 20% to 80%. Serum alanine aminotransferase after H/R increased 2.2-fold in vehicle as compared with simvastatin-treated rats. Histopathological analysis revealed decreased hepatic necrosis in simvastatin-treated rats after H/R. Hepatic oxidative (4-hydroxynonenal) and nitrosative (3-nitrotyrosine) stress, inflammatory markers (serum IL-6 and hepatic infiltration with polymorphonuclear leukocytes), and actin cytoskeleton rearrangements were decreased after simvastatin pretreatment compared with vehicle-treated rats after H/R. Simvastatin increased eNOS and heme oxygenase 1 expression and eNOS activation. Expression of Rho/Rho-kinase and myosin phosphatase targeting subunit, Thr-MYPT1, a marker for Rho-kinase activity, decreased after simvastatin treatment compared with vehicle-treated rats after H/R. Simvastatin pretreatment exerts beneficial effects in this model of acute inflammation by supporting protective mechanisms that are important for hepatic microcirculation after H/R.

Fluvastatin in the first-line therapy of acute coronary syndrome: results of the multicenter, randomized, double-blind, placebo-controlled trial (the FACS-trial)

BACKGROUND

Statins have been proved to be effective in reduction of mortality and morbidity when started in the early secondary prevention in stabilized patients after acute coronary syndrome (ACS). The safety and efficacy of statin administration directly in the first-line therapy in unstable ACS patients is not clear. The aim of our study was, therefore, to assess the effect of statin treatment initiated immediately at hospital admission of patients with ACS.

METHODS

The trial was stopped prematurely after enrollment of one hundred and fifty-six patients with ACS that were randomized at admission to fluvastatin 80 mg (N = 78) or placebo (N = 78). Study medication was administered immediately after randomization and then once daily for 30 days; all patients were then encouraged to continue in open-label statin therapy and at the end of one-year follow-up 75% in the fluvastatin group and 78% in the placebo group were on statin therapy.

RESULTS

We did not demonstrate any difference between groups in the level of C-reactive protein, interleukin 6, and pregnancy-associated plasma protein A on Day 2 and Day 30 (primary endpoint). Fluvastatin-therapy, however, significantly reduced one-year occurrence of major adverse cardiovascular events (11.5% vs. 24.4%, odds ratio (OR) 0.40, 95% CI 0.17-0.95, P = 0.038). This difference was caused mainly by reduction of recurrent symptomatic ischemia (7.7% vs. 20.5%, OR 0.32, 95% CI 0.12-0.88, P = 0.037).

CONCLUSIONS

This study failed to prove the effect of fluvastatin given as first-line therapy of ACS on serum markers of inflammation and plaque instability. Fluvastatin therapy was, however, safe and it may reduce cardiovascular event rate that supports immediate use of a statin in patients admitted for ACS.

TRIAL REGISTRATION

NCT00171275.

Effects of simvastatin on lung injury induced by ischaemia-reperfusion of the hind limbs in rats

We investigated whether simvastatin reduces lung injury caused by ischaemia-reperfusion of the hind limbs in rats. The control group underwent dissection of bilateral femoral arteries; another group (I/R group) underwent ischaemia of bilateral hind limbs for 2 h followed by 3 h reperfusion; and two other groups were pretreated with 5 or 10 mg/kg per day simvastatin for 3 days and then underwent ischaemia-reperfusion. The control and I/R group rats received placebo (water) instead of simvastatin. The lungs of the I/R rats showed marked histopathological changes compared with the other groups. Lung tissue myeloperoxidase, malondialdehyde, neutrophil count and lung injury scores in both simvastatin groups were significantly lower than in the I/R group; 10 mg/kg per day simvastatin significantly reduced lung water content although 5 mg/kg per day did not. Expression of haem oxygenase-1 (HO-1) protein in lung tissue was significantly greater in the simvastatin groups than in the I/R group. Simvastatin protects against lung injury associated with lower extremity ischaemia-reperfusion by reduction of neutrophil aggregation and oxidative damage, and upregulation of HO-1 expression in the injured lung.

Simvastatin Increases Neutrophil Apoptosis and Reduces Inflammatory Reaction After Coronary Surgery

BACKGROUND

Neutrophils play a central role in systemic inflammatory reaction after cardiopulmonary bypass. Apoptosis is significantly delayed, and this might exacerbate systemic and myocardial damage. We tested the hypothesis of whether pretreatment with simvastatin increases the apoptotic rate of neutrophils and hence reduces the entity of inflammatory reaction.

METHODS

Thirty patients undergoing coronary surgery with cardiopulmonary bypass were randomized to treatment with either simvastatin (40 mg/day) or placebo for 3 weeks before surgery. A group of 15 patients undergoing off-pump coronary surgery served as controls. Blood samples for detection of serum cytokine levels were obtained before anesthesia, at the end of surgery, and at 4, 24, 48, and 72 hours postoperatively. Apoptosis and indices of activation were assessed in cultured neutrophils.

RESULTS

Simvastatin significantly reduced the postoperative peak values of interleukin (IL)-6 and IL-8. The neutrophil apoptotic rate was significantly higher among neutrophils obtained from patients pretreated with simvastatin (p < 0.05 at both 8 and 24 hours) compared with placebo. Neutrophils from the statin group had depressed functional activity, as underscored by significantly lower values of CD11b (p < 0.01 at 24 hours) and a significantly less percentage of cells positive for nitro-blue tetrazolium (p < 0.01 at 12 and 24 hours) compared with placebo.

CONCLUSIONS

This randomized, double-blind study indicates that statin therapy before cardiopulmonary bypass is associated with reduction of circulating markers of inflammation and increased neutrophil apoptosis. These data support a routine inclusion of statins as an adjuvant pharmacologic therapy before cardiopulmonary bypass surgery.