Non-lipid-lowering effects of statins on atherosclerosis

Beneficial Effect of Rosuvastatin Therapy on Spleen Injury Induced by Gamma Irradiation in Rats: Targeting Nrf2/EPRE Pathway

Purpose

The present study investigates the new approach of rosuvastatin (RUV) administration as a drug for the management of spleen injury induced by gamma irradiation.

Main Methods

Forty rats were used and divided equally into 4 groups: control group, irradiated group, IRR + rosuvastatin group (10 mg/Kg b. wt), and IRR + rosuvastatin group (20 mg/kg b. wt) for 7 days orally.

Results

The possible curative effect can be illustrated via the improvement of hematopoietic cell count (Hb, RBCs, and WBCs) and oxidative stress markers (MDA and GST) in addition to biochemical parameters including [heme oxigenase-1 (HO-1), nuclear erythroid 2-related factor (Nrf2), NOD-, LRR- and pyrin domain- containing protein 3 (NLRP3) inflammasome] and immune assay of nuclear factor kappa beta (NF-kB P65) and inducible nitric oxide synthase (iNOS). Histological pictures emphasize the biochemical findings. Rosuvastatin treatments by using two different doses improve the tested parameters. High-dose administration of RUV (20 mg/kg p.o.) recorded better results than the low dose (10 mg/kg p.o.).

Conclusion

Our results suggested that rosuvastatin reversed the radiation-induced spleen-damaging effects. So, RUV can be introduced to the market as a new therapy for the management of spleen damages.

Enhancing the biopharmaceutical attributes of atorvastatin calcium using polymeric and lipid-polymer hybrid nanoparticles: An approach for atherosclerosis treatment

Atherosclerosis is associated with inflammation in the arteries, a significant cause of heart attacks and strokes. Although statin therapy can reduce the chances of atherosclerotic plaque formation, they need to be administered in high doses due to low systemic bioavailability and encountered with side effects. To overcome these challenges, we developed nanoparticles using biocompatible and biodegradable lipids and polymers for improving systemic drug absorption and therapeutic response. The polymeric nanoparticles were prepared using PLGA and PVA, while hybrid nanoparticles were prepared using PLGA and Phospholipon 90 G. Both nanoparticles were systematically optimized by I-optimal response surface design. The optimum formulation composition exhibited particle size of less than 250 nm, polydispersity index of less than 0.3, entrapment efficiency of more than 70%, and sustained drug release up to 6 h. In vivo pharmacokinetic evaluation in rats indicated multi-fold improvement in the extent of drug absorption (C_max and AUC_total) for atorvastatin from the nanoparticles vis-à-vis the pure drug suspension. In vivo pharmacodynamic studies also indicated the excellent ability of nanoparticles to lower the elevated levels of lipids (total cholesterol, triglycerides, and low-density lipoproteins) and increase the level of high-density lipoproteins as compared to that of the pure drug suspension.

Combined Administration of Pravastatin and Metformin Attenuates Acute Radiation-Induced Intestinal Injury in Mouse and Minipig Models

Radiation-induced gastrointestinal (GI) damage is one of the critical factors that serve as basis for the lethality of nuclear accidents or terrorism. Further, there are no Food and Drug Administration-approved agents available to mitigate radiation-induced intestinal injury. Although pravastatin (PS) has been shown to exhibit anti-inflammatory and epithelial reconstructive effects following radiation exposure using mouse and minipig models, the treatment failed to improve the survival rate of high-dose irradiated intestinal injury. Moreover, we previously found that metformin (MF), a common drug used for treating type 2 diabetes mellitus, has a mitigating effect on radiation-induced enteropathy by promoting stem cell properties. In this study, we investigated whether the combined administration of PS and MF could achieve therapeutic effects on acute radiation-induced intestinal injury in mouse and minipig models. We found that the combined treatment markedly increased the survival rate and attenuated histological damage in a radiation-induced intestinal injury mouse model, in addition to epithelial barrier recovery, anti-inflammatory effects, and improved epithelial proliferation with stem cell properties. Furthermore, in minipig models, combined treatment with PS and MF ameliorates gross pathological damage in abdominal organs and attenuated radiation-induced intestinal histological damage. Therefore, the combination of PS and MF effectively alleviated radiation-induced intestinal injury in the mouse and minipig models. We believe that the combined use of PS and MF is a promising therapeutic approach for treating radiation-induced intestinal injury.

Atorvastatin Inhibits Endothelial PAI-1-Mediated Monocyte Migration and Alleviates Radiation-Induced Enteropathy

Intestinal injury is observed in cancer patients after radiotherapy and in individuals exposed to radiation after a nuclear accident. Radiation disrupts normal vascular homeostasis in the gastrointestinal system by inducing endothelial damage and senescence. Despite advances in medical technology, the toxicity of radiation to healthy tissue remains an issue. To address this issue, we investigated the effect of atorvastatin, a commonly prescribed hydroxy-3-methylglutaryl-coenzyme A reductase inhibitor of cholesterol synthesis, on radiation-induced enteropathy and inflammatory responses. We selected atorvastatin based on its pleiotropic anti-fibrotic and anti-inflammatory effects. We found that atorvastatin mitigated radiation-induced endothelial damage by regulating plasminogen activator inhibitor-1 (PAI-1) using human umbilical vein endothelial cells (HUVECs) and mouse model. PAI-1 secreted by HUVECs contributed to endothelial dysfunction and trans-endothelial monocyte migration after radiation exposure. We observed that PAI-1 production and secretion was inhibited by atorvastatin in irradiated HUVECs and radiation-induced enteropathy mouse model. More specifically, atorvastatin inhibited PAI-1 production following radiation through the JNK/c-Jun signaling pathway. Together, our findings suggest that atorvastatin alleviates radiation-induced enteropathy and supports the investigation of atorvastatin as a radio-mitigator in patients receiving radiotherapy.

Pravastatin Attenuates Acute Radiation-Induced Enteropathy and Improves Epithelial Cell Function

Background and Aim: Radiation-induced enteropathy is frequently observed after radiation therapy for abdominal and pelvic cancer or occurs secondary to accidental radiation exposure. The acute effects of irradiation on the intestine might be attributed to inhibition of mitosis in the crypts, as the loss of proliferative functions impairs development of the small intestinal epithelium and its barrier function. Especially, oxidative damage to intestinal epithelial cells is a key event in the initiation and progression of radiation-induced enteropathy. Pravastatin is widely used clinically to lower serum cholesterol levels and has been reported to have anti-inflammatory effects on endothelial cells. Here, we investigated the therapeutic effects of pravastatin on damaged epithelial cells after radiation-induced enteritis using in vitro and in vivo systems. Materials and Methods: To evaluate the effects of pravastatin on intestinal epithelial cells, we analyzed proliferation and senescence, oxidative damage, and inflammatory cytokine expression in an irradiated human intestinal epithelial cell line (InEpC). In addition, to investigate the therapeutic effects of pravastatin in mice, we performed histological analysis, bacterial translocation assays, and intestinal permeability assays, and also assessed inflammatory cytokine expression, using a radiation-induced enteropathy model. Results: Histological damage such as shortening of villi length and impaired intestinal crypt function was observed in whole abdominal-irradiated mice. However, damage was attenuated in pravastatin-treated animals, in which normalization of intestinal epithelial cell differentiation was also observed. Using in vitro and in vivo systems, we also showed that pravastatin improves the proliferative properties of intestinal epithelial cells and decreases radiation-induced oxidative damage to the intestine. In addition, pravastatin inhibited levels of epithelial-derived inflammatory cytokines including IL-6, IL-1β, and TNF-α in irradiated InEpC cells. We also determined that pravastatin could rescue intestinal barrier dysfunction via anti-inflammatory effects using the mouse model. Conclusion: Pravastatin has a therapeutic effect on intestinal lesions and attenuates radiation-induced epithelial damage by suppressing oxidative stress and the inflammatory response.

Brain proteomics identifies potential simvastatin targets in acute phase of stroke in a rat embolic model

Finding an efficient neuroprotectant is of urgent need in the field of stroke research. The goal of this study was to test the effect of acute simvastatin administration after stroke in a rat embolic model and to explore its mechanism of action through brain proteomics. To that end, male Wistar rats were subjected to a Middle Cerebral Arteria Occlusion and simvastatin (20 mg/kg s.c) (n = 11) or vehicle (n = 9) were administered 15 min after. To evaluate the neuroprotective mechanisms of simvastatin, brain homogenates after 48 h were analyzed by two-dimensional fluorescence Difference in Gel Electrophoresis (DIGE) technology. We confirmed that simvastatin reduced the infarct volume and improved neurological impairment at 48 h after the stroke in this model. Considering our proteomics analysis, 66 spots, which revealed significant differences between groups, were analyzed by matrix-assisted laser desorption/ionization-time of flight mass spectrometry allowing the identification of 27 proteins. From these results, we suggest that simvastatin protective effect can be partly explained by the attenuation of the oxidative and stress response at blood-brain barrier level after cerebral ischemia. Interestingly, analyzing one of the proteins (HSP75) in plasma from stroke patients who had received simvastatin during the acute phase, we confirmed the results found in the pre-clinical model. Our aim was to study statins benefits when administered during the acute phase of stroke and to explore its mechanisms of action through brain proteomics assay. Using an embolic model, simvastatin-treated rats showed significant infarct volume reduction and neurological improvement compared to vehicle-treated group. Analyzing their homogenated brains by two-dimensional fluorescence Difference in Gel Electrophoresis (DIGE) technology, we concluded that the protective effect of simvastatin can be attributable to oxidative stress response attenuation and blood-brain barrier protection after cerebral ischemia.

Neuro, cardio, and reno protective activities of rosuvastatin in streptozotocin-induced type 2 diabetic rats undergoing treatment with metformin and glimepiride

Diabetes is associated with complications like neuropathy, nephropathy, cardiomyopathy, and retinopathy due to increased oxidative stress and serum lipids. In the present study, rosuvastatin, a HMG-CoA inhibitor, was investigated for its protective effect in neuropathy, nephropathy, and cardiomyopathy based on the lipid-lowering property along with its pleiotropic effects such as improved blood flow to the organ and antioxidant defense. Type 2 diabetes was induced in Wistar rats by single i.p. administration of streptozotocin (50 mg/kg). These diabetic rats were treated with daily doses of rosuvastatin (10 mg/kg) alone, metformin (120 mg/kg) and glimepiride (1 mg/kg) and rosuvastatin in combination with metformin (120 mg/kg) and glimepiride (1 mg/kg) for a period of 6 weeks. The biochemical parameters involved in neuropathy, renopathy, and cardiopathy were estimated. Treatment resulted in significant (P < 0.05) decrease in thiobarbituric acid reactive substances (TBARS) and increase in levels of glutathione peroxidise and catalase in brain and kidney homogenates. Significant (P < 0.05) increase in high-density lipoproteins and decrease in creatinine kinase, triglycerides, total serum cholesterol represents the cardioprotective action, whereas significant (P < 0.05) increase in the latency in the hotplate model shows the neuroprotective activity, and significant (P < 0.05) decrease in blood urea nitrogen, creatinine levels and increase in serum total protein levels suggested the renoprotective actions. The unique properties of rosuvastatin such as antioxidant defense and lipid-lowering nature might have resulted in cardio, neuro, and renoprotective activity in type 2 diabetic rats treated with metformin and glimepiride.

Combining statins with tissue plasminogen activator treatment after experimental and human stroke: a safety study on hemorrhagic transformation

AIMS

Statins may afford neuroprotection against ischemic injury, but it remains controversial whether combined treatment with tissue plasminogen activator (tPA) after stroke increases the risk of hemorrhagic transformation (HT), the major tPA-related complication. We evaluated the safety of combining statin with tPA administration during the acute phase of both experimental and human stroke.

METHODS

The occurrence and severity of HT, infarct volume, and neurological outcome were evaluated in spontaneous hypertensive rats (SHR) subjected to embolic middle cerebral arterial occlusion (MCAO), which received vehicle or simvastatin (20 mg/kg), 15 min after ischemia and tPA (9 mg/kg) 3 h after ischemia. Additionally, HT rate was evaluated in stroke patients who were treated with tPA (0.9 mg/kg) within 3 h after symptom onset, considering whether or not were under statins treatment when the stroke occurred.

RESULTS

In the experimental study, no differences in HT rates and severity were found between treatment groups, neither regarding mortality, neurological deficit, infarct volume, or metalloproteinases (MMPs) brain content. In the clinical study, HT rates and hemorrhage type were similar in stroke patients who were or not under statins treatment.

CONCLUSION

This study consistently confirms that the use of statins does not increase HT rates and severity when is combined with tPA administration.

Statins as modulators of regulatory T-cell biology

Statins are pharmacological inhibitors of the activity of 3-hydroxy-3-methyl-glutaryl-CoA reductase (HMGCR), an enzyme responsible for the synthesis of cholesterol. Some recent experimental studies have shown that besides their effects on the primary and secondary prevention of cardiovascular diseases, statins may also have beneficial anti-inflammatory effects through diverse mechanisms. On the other hand, the induction and activity of regulatory T cells (Treg) are key processes in the prevention of pathology during chronic inflammatory and autoimmune diseases. Hence, strategies oriented towards the therapeutic expansion of Tregs are gaining special attention among biomedical researchers. The potential effects of statins on the biology of Treg are of particular importance because of their eventual application as in vivo inducers of Treg in the treatment of multiple conditions. In this paper we review the experimental evidence pointing out to a potential effect of statins on the role of regulatory T cells in different conditions and discuss its potential clinical significance.

Beneficial effects of pitavastatin, a 3-hydroxy-3-methylglutaryl coenzyme a reductase inhibitor, on cardiac function in ischemic and nonischemic heart failure

HMG-CoA reductase inhibitors (statins) have recently been reported to improve cardiac function, and decrease the incidence of heart failure (HF) in hyperlipidemic patients. However, evidence for statin treatment in patients with HF remains a subject of debate. Thus, a study was initiated to examine the effects of pitavastatin on cardiac function evaluated by echocardiographic findings and plasma brain natriuretic peptide (BNP) levels in patients with HF. Twenty-three patients with HF were treated with pitavastatin 1-2 mg/day in addition to standard therapy for 7.5 +/- 3.8 months. Left ventricular end-diastolic dimension (LVDd) and left ventricular end-systolic dimension (LVDs) were determined by echocardiography. Left ventricular ejection fraction (LVEF) was calculated using Teichholz's formula. Serum lipid and plasma BNP levels were also measured. During the follow-up period, LVEF was increased from 42 +/- 11 to 48 +/- 13% (P = 0.002). LVDs was reduced from 43 +/- 10 to 40 +/- 10 mm (P < 0.001), while there was no change in LVDd. E/A (n = 10) and deceleration time (n = 7), obtained in some patients, did not change significantly (0.89 +/- 0.33 to 0.77 +/- 0.17%, and 215 +/- 46 to 227 +/- 72 msec, respectively). In addition, the plasma BNP level was moderately, but significantly decreased from 94 +/- 78 to 70 +/- 56 pg/mL (P = 0.005). In subgroup analysis, LVEF was improved in both patients with ischemic and nonischemic HF. There was no significant correlation between the percent change in serum total cholesterol and the percent change in LVEF by pitavastatin treatment. Serum total cholesterol, LDL-cholesterol, and triglycerides decreased by 21%, 30%, and 15%, respectively, and HDL-cholesterol increased by 12%. Pitavastatin improved cardiac function in patients with HF, which generally worsens with time. The results suggest that pitavastatin may be beneficial for treatment of HF.

Role of statin therapy in stroke prevention

Serum cholesterol levels have been associated with atherosclerosis and the lowering of serum cholesterol with hydroxy-methyl coenzyme A reductase inhibitors, or statins, has been shown to decrease cardiovascular events. Though early epidemiologic data found conflicting results regarding serum cholesterol levels and stroke, randomized clinical trials of statins for coronary heart disease prevention showed a clear reduction in the incidence of stroke. This review summarizes the clinical trial data surrounding lipid lowering for stroke prevention while also exploring potential mechanisms for such an effect. Particular attention is given to trials for primary and secondary prevention of stroke relevant to the hypertensive individual, and the impact of hemorrhagic vs. ischemic stroke in the outcomes of these trials.

Simvastatin improves endothelial function in patents with subclinical hypothyroidism

Patients with subclinical hypothyroidism (SCH) have impaired endothelial function probably related to dyslipidemia. The present study compares the effects of simvastatin versus levothyroxine (LT-4) treatment on lipid profile and endothelial function in patients with SCH. Fifty-nine patients with newly diagnosed SCH were enrolled. Patients were randomized into 3 groups to receive no treatment (n = 19), LT-4 (n = 20), or simvastatin (n = 20). We measured endothelium-dependent vasodilation (EDV) and endothelium-independent vasodilation (EIV) at baseline and after 8 months. Serum total cholesterol, triglycerides and LDL-cholesterol were significantly lower following simvastatin. EDV increased significantly in simvastatin treatment group (7.5% +/- 3.3% vs 14.0% +/- 4.5% (P < 0.01). The improvement of EDV correlated with the percent decrease of LDL-cholesterol (rho = 0.68, P < 0.01). Although LT-4 therapy caused a trend towards an increase in EDV compared to baseline, statistical significance was not achieved. EIV remained unchanged in all three groups. Simvastatin but not LT-4 treatment significantly improves EDV of the brachial artery and dyslipidemia in patients with SCH. Improvement in brachial artery endothelial function may be related in part to a hypolipidemic effect of simvastatin treatment.

Atorvastatin reduces tissue factor expression in adipose tissue of atherosclerotic rabbits

BACKGROUND

We have recently demonstrated that tissue factor (TF) expression increases in adipose tissues/adipocytes of cholesterol-fed rabbit, which is associated with a hypercoagulable state that contributes to thrombosis. In this study, we evaluated the ability of atorvastatin to modulate TF expression in cholesterol-fed rabbit and the regulatory mechanism.

METHODS

Male rabbits were randomly fed with normal diet and high-cholesterol diet for 8 weeks, following 4 weeks, those fed high-cholesterol diet were randomly assigned to atorvastatin or starch. At the end of 12 weeks, subcutaneous adipose was collected, and culture adipocyte. TF mRNA was detected by reverse transcription-polymerase chain reaction (RT-PCR). TF concentrations were determined with ELISA. The in vitro effect of atorvastatin and mevalonate (MVA) on TF production in adipocytes was observed.

RESULTS

Atorvastatin reduced serum TC and LDL-C levels (P<0.05), and decreased plasma TF concentration and expression in adipose tissues/adipocytes from cholesterol-fed rabbits. In vitro, atorvastatin dose-dependently suppressed TF expression and protein secretion in adipocytes. MVA reversed the inhibitory effect of atorvastatin on TF expression in concentration-dependent manner.

CONCLUSIONS

Results provide further support for the antithrombotic effect of atorvastatin. It also indicated that mevalonate pathway may play an important role in TF expression in adipocyte.

Effect of clopidogrel on the inflammatory progression of early atherosclerosis in rabbits model

Atherosclerosis is an inflammatory response of the arterial wall to 'injury', which is prominently driven by inflammatory factors. Clopidogrel reduces early atherosclerosis, however, the role of clopidogrel in modulating inflammatory progression of atherosclerosis is less investigated. We wished to determine the effect of clopidogrel on progression of established atherosclerosis, vascular inflammatory factors and compared with that of aspirin and atorvastatin. Fifty male New Zealand white (NZW) rabbits were divided into five groups randomly including negative group. The rabbits were fed with a normal diet or a high cholesterol diet for 7 weeks. The right iliac artery of animals except negative group were balloon injured 1 week after initiation of the diet, then animals were treated with clopidogrel (4 mg/kg/day), aspirin (12 mg/kg/day), atorvastatin (2.5mg/kg/day) or placebo for 6 weeks. At the end of the study, the placebo (positive) group had significant progression of atherosclerosis compared with negative group. In contrast, clopidogrel, aspirin or atorvastatin treated rabbits showed a significant reduction in progression of atherosclerosis and decreased the levels of P-selection, intercellular adhesion molecule-1 (ICAM-1), vascular adhesion molecule-1 (VCAM-1) and monocyte chemotactic protein-1 (MCP-1) in serum and vascular wall. Among three drugs, the action of clopidogrel is the most powerful in decreasing the levels of inflammatory factors. These results suggest that in a rabbit atherosclerosis model, clopidogrel retards the progression of established lesions and that this effect is paralleled by a suppression of inflammatory factors.

The HMG-CoA reductase inhibitor, pravastatin, prevents the development of monocrotaline-induced pulmonary hypertension in the rat through reduction of endothelial cell apoptosis and overexpression of eNOS

HMG-CoA reductase inhibitors improve endothelial function and exert antiproliferative effects on vascular smooth muscle cells of systemic vessels. This study was aimed to assess the protective effects of pravastatin (an HMG-CoA reductase inhibitor) against monocrotaline-induced pulmonary hypertension in rats. Pravastatin (PS, 10 mg/kg/day) or vehicle were given orally for 28 days to Wistar male rats injected or not with monocrotaline (MC, 60 mg/kg intraperitonealy) and treated or not by N(omega)-nitro-L-arginine methyl ester (L-NAME) 15 mg/kg/day. At 4 weeks, monocrotaline-injected rats developed severe pulmonary hypertension, with an increase in right ventricular pressure (RVP) and right ventricle/left ventricle+septum weight ratio (RV/LV+S), associated with a decrease in pulmonary artery dilation induced either by acetylcholine or sodium nitroprusside. Hypertensive pulmonary arteries exhibited an increase in medial thickness, medial wall area, endothelial cell apoptosis, and a decrease of endothelial nitric oxide synthase (eNOS) expression. Monocrotaline-rat lungs showed a significant decrease of eNOS expression (4080+/-27 vs 12189+/-761 arbitrary density units [ADU] for MC and control groups respectively, P<0.01) and a significant increase of cleaved caspase-3 expression by western blotting (Control=11628+/-2395 vs MC=2326+/-2243 ADU, P<0.05). A non-significant trend toward a reduced mortality was observed with pravastatin (relative risk of death = 0.33; 95% confidence interval [0.08-1.30], P= 0.12 for MC+PS vs MC groups). Pravastatine induced a protection against the development of the pulmonary hypertension (RVP in mmHg: 30+/-3 vs 45+/-4 and RV/LV+S: 0.46+/-0.04 vs 0.62+/-0.05 for MC+PS and MC groups respectively, P<0.05) and was associated with a significant reduction of MC-induced thickening (61+/-6 mum vs 81+/-3 mum for MC+PS and MC groups respectively, P= 0.01) of the medial wall of the small intrapulmonary arteries. Pravastatin partially restored acetylcholine-induced pulmonary artery vasodilation in MC rats (Emax=65+/-5% and 46+/-3% for MC+PS and MC group respectively, P<0.05) but had no effect on acetylcholine-induced pulmonary artery vasodilation in MC+L-NAME rats. It also prevented apoptosis and restored eNOS expression of pulmonary artery endothelial cells, as well as in the whole lung. Pravastatin reduces the development of monocrotaline-induced pulmonary hypertension and improves endothelium-dependent pulmonary artery relaxation, probably through a reduced apoptosis and a restored eNOS expression of endothelial cells.

Atorvastatin inhibits inflammatory hypernociception

BACKGROUND AND PURPOSE

Atorvastatin is an inhibitor of the enzyme 3-hydroxyl-3-methylglutaryl coenzyme A reductase used to prevent coronary heart disease. We have studied the analgesic effect of atorvastatin in inflammatory models in which a sequential release of mediators (bradykinin, (BK), tumour necrosis factor-alpha (TNF-alpha), interleukin-1beta (IL-1beta) and the chemokine, KC/CXCL) links the stimulus with release of directly acting hypernociceptive mediators such as prostaglandin E(2) (PGE(2)).

EXPERIMENTAL APPROACH

The effects of orally administered atorvastatin on inflammatory mechanical hypernociception in mouse paws were evaluated with an electronic pressure-meter. Cytokines and PGE(2) were measured by ELISA and RIA.

KEY RESULTS

Treatment with atorvastatin for 3 days dose-dependently reduced hypernociception induced by lipopolysaccharide (LPS) or that following antigen challenge in sensitized animals. Atorvastatin pre-treatment reduced hypernociception induced by bradykinin and cytokines (TNF-alpha, IL-1beta and KC), and the release of IL-1beta and PGE(2) in paw skin, induced by lipopolysaccharide. The antinociceptive effect of atorvastatin on LPS-induced hypernociception was prevented by mevalonate co-treatment without affecting serum cholesterol levels. Hypernociception induced by PGE(2) was inhibited by atorvastatin, suggesting intracellular antinociceptive mechanisms for atorvastatin. The antinociceptive effect of atorvastatin upon LPS- or PGE(2)-induced hypernociception was prevented by non-selective inhibitors of nitric oxide synthase (NOS) but not by selective inhibition of inducible NOS or in mice lacking this enzyme.

CONCLUSIONS AND IMPLICATIONS

Antinociceptive effects of atorvastatin depend on inhibition of cytokines and prostanoid production and on stimulation of NO production by constitutive NOS. Our study suggests that statins may constitute a novel class of analgesic drugs.

Atorvastatin reduces plasminogen activator inhibitor-1 expression in adipose tissue of atherosclerotic rabbits

BACKGROUND

Plasminogen activator inhibitor-1 (PAI-1) expression are increased in adipose tissues/adipocytes of obese mice, which is associated with a hypofibrinolytic state that contributes to thrombosis. We recently demonstrated that PAI-1 expression increases in adipose tissues/adipocytes of cholesterol-fed rabbits. In this study, we evaluated the ability of atorvastatin to modulate PAI-1 expression in cholesterol-fed rabbits and the regulatory mechanism.

METHODS

Male rabbits were randomly fed with normal diet and high-cholesterol diet for 8 weeks, following 4 weeks, those fed high-cholesterol diet were randomly assigned to 2.5 mg/kg/day atorvastatin or starch. At the end of 12 weeks, subcutaneous adipose was collected, and culture adipocyte. PAI-1 mRNA was detected by RT-PCR. PAI-1 concentrations were determined with ELISA. The effect of atorvastatin and mevalonate (MVA) on PAI-1 production in adipocytes in vitro was observed.

RESULTS

Atorvastatin significantly reduced serum TC and LDL-C concentrations (p<0.05), and decreased plasma PAI-1 concentration and PAI-1 expression in adipose tissues/adipocytes from cholesterol-fed rabbits. In vitro, atorvastatin dose-dependently suppressed PAI-1 expression and protein secretion in adipocytes. MVA reversed the inhibitory effect of atorvastatin on PAI-1 expression in concentration-dependent manner.

CONCLUSIONS

Atorvastatin reduces plasma PAI-1 concentration and PAI-1 expression in adipose tissue and adipocyte of atherosclerotic rabbit, and inhibits PAI-1 expression and protein secretion in adipocytes in vitro, suggesting that it may have an antithrombtic effect. We also suggest that the mevalonate pathway may play an important role in PAI-1 expression in adipocyte.

Statin therapy in heart failure

PURPOSE OF REVIEW

The 3-hydroxy-3-methylglutaryl-coenzyme-A reductase inhibitors, or statins, have been shown to reduce cardiovascular morbidity and mortality among a wide spectrum of patients with established atherosclerotic vascular disease. Mounting experimental and clinical evidence also suggest a potential benefit as well as theoretical harm of statin therapy in patients with heart failure.

RECENT FINDINGS

This article briefly summarizes the therapeutic properties of statins that may be of benefit to patients with heart failure and the theoretical adverse effects of cholesterol reduction in this group of patients. A number of nonrandomized clinical studies over the past several years have shown an association between statin use and reduced overall mortality. Several large-scale randomized studies designed to confirm these findings are currently under way.

SUMMARY

Statin therapy appears to improve clinical outcomes in patients with both ischemic and nonischemic cardiomyopathy independently of their cholesterol-lowering properties. The theoretical adverse properties of statins in heart failure patients have not been substantiated in small to medium-sized clinical trials. Although the encouraging results of these preliminary studies suggest a role for statin therapy in heart failure, larger studies are needed to validate these findings. Several ongoing randomized trials are currently under way to evaluate the effect of statin therapy on cardiovascular outcomes in heart failure patients. The results of these studies, expected in the next several years, should provide scientific evidence for the role of statins in the treatment of failure.

Tactics for Vascular Protection After Acute Ischemic Stroke

BACKGROUND

The vascular events that happen during ischemic stroke worsen outcomes in patients by causing edema, hemorrhagic transformation, and general neurologic tissue compromise. In the past 2 decades, clinical trials in patients after ischemic stroke focused on neuroprotection, but these strategies have failed in providing actual benefit. Vascular protection represents a new field to be explored in acute ischemic stroke in order to develop new approaches to therapeutic intervention.

PURPOSE

We identified tactics likely to provide vascular protection in patients with ischemic stroke. These tactics are based on knowledge of the molecular processes involved.

SUMMARY OF REVIEW

The pathologic processes due to vascular injury after an occlusion of a cerebral artery can be separated into acute (those occurring within hrs), subacute (hrs to days), and chronic (days to mo). Targets for intervention can be identified for all three stages. In the acute phase, superoxide is the predominant mediator, followed by inflammatory mediators and proteases in the subacute phase. In the chronic phase, proapoptotic gene products have been implicated. Many already-marketed therapeutic agents (statins, angiotensin modulators, erythropoietin, minocycline, and thiazolidinediones), with proven safety in patients, have been shown to have activity against some of the key targets of vascular protection.

CONCLUSION

Currently available pharmacologic agents are poised for clinical trials of vascular protection after acute ischemic stroke.

HMG-CoA reductase inhibitors induce COX-2 gene expression in murine macrophages: role of MAPK cascades and promoter elements for CREB and C/EBPβ

Except functioning as lipid-lowering agents, HMG-CoA inhibitors, statins, are good tools to clarify the signaling role of small G proteins. In this study, we found in murine RAW264.7 macrophages, statins within 1-30 microM stimulated COX-2 gene transcription and PGE(2) formation, displaying potencies as lovastatin > fluvastatin > atorvastatin >> pravastatin. Transfection experiments with COX-2 promoter construct showed the necessity of C/EBPbeta and CRE promoter sites, but not NF-kappaB promoter site. Effects of statins on the activation of COX-2 promoter, induction of COX-2 protein, and PGE(2) production were all prevented by mevalonate and prenylated metabolites, FPP and GGPP. Consistent with the effect of statins, manumycin A, farnesyltransferase inhibitor, and geranylgeranyltransferase inhibitor increased PGE(2) production and COX-2 induction. Likewise, toxin B, an inhibitor of Rho family members, caused a prominent COX-2 induction. Results also indicated that tyrosine kinase, ERK, and p38 MAPK play essential roles in statin action. Taken together, these results not only demonstrate a unique action of statins in the upregulation of COX-2 expression in macrophages, but also suggest a negative role controlled by small G proteins in COX-2 gene regulation. Removal of this negative control by impairing G protein prenylation with statins leads to MAPKs activation and promotes COX-2 gene expression through the activation at CRE and C/EBPbeta sites.

Effects of conventional and aggressive statin treatment on markers of endothelial function and inflammation

BACKGROUND

Atherosclerosis is considered to be a chronic inflammatory disorder. Several large-scale clinical studies demonstrate that markers of inflammation, such as high-sensitivity C-reactive protein (hsCRP), fibrinogen, and soluble CD40 ligand, are potent and independent predictors of vascular risk.

HYPOTHESIS

The study was undertaken to investigate the effect of increasing the statin dose from conventional to aggressive treatment on lipids levels, inflammation, and endothelial function in patients with coronary artery disease (CAD).

METHODS

We randomized 97 patients to either 20 mg simvastatin or 80 mg atorvastatin. Plasma levels of lipids, hsCRP, fibrinogen, soluble adhesion molecules, and nitric oxide-total were analyzed at baseline and after 6 months of treatment.

RESULTS

Lipid values were significantly reduced in both treatment groups, but with significantly greater reduction in the aggressively treated group. Furthermore, aggressive statin treatment significantly decreased hsCRP and fibrinogen, while only small reductions were seen in the conventionally treated group, resulting in significant differences between the two treatment groups (p < 0.001). Nitric oxide-total increased significantly in both treatment groups, although the increase was more pronounced in the aggressively treated group (22.6 vs. 15.6%).

CONCLUSION

Aggressive statin treatment significantly improved lipid status and reduced markers of inflammation and improved endothelial function compared with conventional treatment in patients with CAD. No interaction was observed, and high-dose treatment did not offer additional benefit compared with standard-dose treatment with respect to soluble adhesion molecules.

Statins in atherosclerosis: lipid-lowering agents with antioxidant capabilities

Low-density lipoprotein (LDL) cholesterol is an established risk factor for coronary heart disease (CHD). In the presence of oxidative stress LDL particles can become oxidized to form a lipoprotein species that is particularly atherogenic. Indeed, oxidized LDL (oxLDL) is pro-inflammatory, it can cause endothelial dysfunction and it readily accumulates within the arterial wall. Several factors may influence the susceptibility of LDL to oxidation, including its size and composition, and the presence of endogenous antioxidant compounds, such as alpha-tocopherol. Individuals with type 2 diabetes or the metabolic syndrome have high levels of oxidative stress and consequently are at an increased risk for cardiovascular events. Reducing oxidative stress has been proposed as a potential approach to prevent CHD and antioxidant vitamins have been employed with encouraging results in experimental models of atherosclerosis. However, clinical trials have not demonstrated consistent beneficial effects of antioxidants on cardiovascular outcomes. Statins (3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors) are the first-line choice for lowering total and LDL cholesterol levels and they have been proven to reduce the risk of CHD. Recent data suggest that these compounds, in addition to their lipid-lowering ability, can also reduce the production of reactive oxygen species and increase the resistance of LDL to oxidation. It may be that the ability of statins to limit the oxidation of LDL contributes to their effectiveness at preventing atherosclerotic disease.

Lipid-lowering therapy

Lipid therapy has come a long way in the past 20 years. In the late 1980s, 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors ("statins") were introduced, and they have continued to demonstrate benefits in multiple large-scale primary and secondary prevention trials. A broader understanding of the effects of statin medications has led to new therapeutic goals for different patient populations. In this article, Dr Smith discusses recent developments in statin therapy as well as the introduction of a new class of drugs called selective cholesterol absorption inhibitors.

Decrease of hemostatic cardiovascular risk factors by aggressive vs. conventional atorvastatin treatment in patients with Type 2 diabetes mellitus

BACKGROUND

Patients with Type 2 diabetes mellitus have increased levels of hemostatic risk variables for cardiovascular disease, such as fibrinogen, von Willebrand factor (VWF), factor (F)VIIa, d-dimer and plasminogen activator inhibitor-1 (PAI-1).

OBJECTIVES

To evaluate the effect of aggressive vs. standard dose atorvastatin on hemostatic cardiovascular risk factors in patients with Type 2 diabetes mellitus.

PATIENTS AND METHODS

The effect of 30 weeks of treatment with atorvastatin 10 and 80 mg on hemostatic cardiovascular risk factors was assessed in a randomized double-blind placebo-controlled trial on 217 patients with Type 2 diabetes mellitus and dyslipidemia.

RESULTS AND CONCLUSIONS

Atorvastatin 10 and 80 mg dose-dependently reduced d-dimer (7.4% and 8.5%, respectively, P for trend = 0.004) and PAI-1 antigen levels (9.0% and 18%, respectively, P for trend = 0.021). Levels of fibrinogen, VWF, tissue-type plasminogen activator and FVIIa were not influenced by atorvastatin. In conclusion, in patients with Type 2 diabetes mellitus, atorvastatin dose-dependently improved the levels of the hemostatic risk variables d-dimer and PAI-1.

Lack of therapeutic interchangeability of HMG-CoA reductase inhibitors

OBJECTIVE

To review relevant literature and provide an opinion on the class effect of hydroxymethylglutaryl coenzyme A reductase inhibitors (statins).

DATA SOURCES

Primary and review articles were identified by MEDLINE search (1990-July 2002).

STUDY SELECTION AND DATA EXTRACTION

Editorials, studies, and review articles related to the class effect or therapeutic interchangeability of statins were reviewed. Also included was information that is relevant to this topic.

DATA SYNTHESIS

Although statins share common main actions, they may have clinically important differences in terms of efficacy and safety. At fixed or allowable dosages, rosuvastatin, atorvastatin, and simvastatin produced greater low-density lipoprotein cholesterol-lowering effects compared with other statins. Some statins have shown reduction in either cardiovascular and/or total mortality. Statins also differ in their structure, pharmacokinetics, potency, and rate of metabolism, any or all of which may have clinical significance. Although inconclusive, subtle differences in nonlipid effects of some statins may have contributed to positive benefits observed in clinical studies. As a result of drug-related deaths, cerivastatin was withdrawn voluntarily from the market, which may raise the question whether there is therapeutic interchangeability (due to class effect) among statins.

CONCLUSIONS

Despite the competition for market share and strategies attempting to identify differences in therapeutic value, few head-to-head comparisons between statins have been performed. The limited, available data suggest that statins are not therapeutically interchangeable.

Physicians' interpretation of "class effects": a need for thoughtful re-evaluation

The concept of pharmacologic "class effects" exists across a broad range of medical products and is particularly pervasive with regard to cardiovascular agents. Evolution of the concept over the past two decades has shown the influence of physicians' practice patterns, pharmaceutical companies, health maintenance organizations and the Food and Drug Administration (FDA). Understanding the evolution of health care, social and economic policies, acknowledging the correction of medical misconceptions and inaccurate understanding and appreciating the emergence of new medical knowledge over the past decade should modify the clinician's viewpoint of "class effects." These revelations should signal caution in extrapolating the outcome efficacy or safety of one agent to another within a pharmacologic class. The authors urge clinicians, pharmaceutical companies, health maintenance organizations and the FDA to re-examine their concept of "class effects." An appeal is made for physicians to prescribe those pharmaceutical agents with definitive evidence of mortality and morbidity efficacy and safety established by appropriately scaled randomized clinical trials.

Modulation of inflammatory mediators and PPARgamma and NFkappaB expression by pravastatin in response to lipoproteins in human monocytes in vitro

Statins are inhibitors of the rate-limiting step of cellular cholesterol synthesis. In vitro and in vivo studies suggest that statins have anti-inflammatory properties independent of their cholesterol-lowering effects. These observations prompted us to examine the effects of pravastatin (50 microM) and native or oxidized low density lipoprotein (nLDL or oxLDL) (50 microg ml(-1)) on primary human monocytes. We found that cells treated with pravastatin prior to nLDL and cells pre-treated with oxLDL prior to pravastatin showed increased activity of peroxisome proliferator-activated receptor gamma (PPAR gamma). Treatment of cells with drug either before incubation with oxLDL or afterwards suppressed nuclear factor kappa B (NF kappa B) expression and reduced uptake of(125)I-oxLDL by 1.7- and 1.5-fold, respectively. Pravastatin also increased PPAR gamma levels and abolished NF kappa B activity in non-stimulated monocytes. Statin added to monocytes prior to or after treatment with nLDL or oxLDL significantly inhibited generation of matrix metalloproteinases (MMPs), monocyte chemotactic protein-1 (MCP-1) and tumor necrosis factor alpha (TNF- alpha). These data corroborate previous findings of the pleiotropic role of statins and also suggest the involvement of transcription factors such as PPAR gamma and NF kappa B in the modulation of the inflammatory processes by statins.

Apoptosis in atherosclerosis: pathological and pharmacological implications

Normal embryonic development, tissue differentiation and repair in the eukaryote requires a tightly regulated apoptosis, or programmed cell death. Apoptosis also plays an essential role in different pathological processes including atherosclerosis, in which it affects all cell types in the atherosclerotic lesion, including endothelial cells, vascular smooth muscle cells, and macrophages. During atherosclerosis progression, pro- and anti-apoptotic signals abound in the evolving lesion. Apoptosis limits the number of a particular cell type that accumulates in the lesion and slows down the overall progression of the lesion. On the other hand, it contributes to the production of unstable plaques. Many pharmacological agents used to treat cardiovascular and lipid disorders have pro- or/and anti-apoptotic effects. Pharmaceuticals that modulate apoptosis in specific types of cell can potentially serve as anti-atherogenic agents. However, to develop agents for clinical use requires a thorough knowledge of the pathophysiology of apoptosis in atheromatous lesions, a highly cell-specific process. Here we review our current understanding of the process to provide a background for future pharmacological research in the area.

If LDL-C is the answer...what was the question? What do the data really show?

The 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors are frequently utilized in the treatment of hypercholesterolemia. With recently completed statin clinical cardiovascular outcomes data available, the purpose of this review is to analyze the relative benefits of each molecule and to determine whether "lower is better" is a correct hypothesis for secondary prevention. Twenty-one clinical studies, each with a duration of statin therapy of 6 months or longer, were reviewed, and the pharmacologic effects of these agents on cardiovascular outcomes was examined. As evaluated by study drug, statistical event reduction was achieved in seven of nine pravastatin studies, one of three simvastatin studies, one of six lovastatin studies, zero of two fluvastatin studies, and zero of one atorvastatin study. Pravastatin was the only statin proven statistically to reduce events in both primary and secondary prevention. Thus, all of the statins do not appear to be the same in terms of their ability to reduce cardiovascular events. Until head-to-head trials have been completed, these clinical outcomes data suggest that in patients with severe hypercholesterolemia who require high-dose statin therapy, simvastatin 80 mg each evening would appear to be the agent of choice. However, pravastatin 40 mg daily at bedtime appears to be a unique molecule, with the strongest evidence for event reduction in the majority of patients with moderate hypercholesterolemia with, or who are at risk for, coronary heart disease.

Basic mechanisms of stroke prevention with lipid-lowering therapy

Cholesterol-lowering therapy has not been considered an important risk factor for stroke; however, lipid-lowering therapies reduce cerebrovascular events in patients with coronary heart disease (CHD). The basic mechanisms of cerebrovascular protection have emphasized reduced atheroemboli from the left ventricle and aortic arch, delayed carotid artery disease progression, stabilization of vulnerable carotid atherosclerotic plaque, and improvement in cerebral blood flow.

Biological basis for statin therapy in stroke prevention

Hypercholesterolemia has not been considered an important risk factor for stroke; however, statin therapy reduces stroke in coronary heart disease patients. Statins may provide cerebrovascular protection through various mechanisms that include a reduction in the incidence of embolic stroke from cardiac, aortic and carotid sites, stabilization of vulnerable carotid atherosclerotic plaque, and improvement in cerebral blood flow.