Rosuvastatin, a 3-hydroxy-3-methylglutaryl coenzyme a reductase inhibitor, decreases cardiac oxidative stress and remodeling in Ren2 transgenic rats

Use of Statins in Heart Failure with Preserved Ejection Fraction: Current Evidence and Perspectives

Systemic inflammation and coronary microvascular endothelial dysfunction are essential pathophysiological factors in heart failure (HF) with preserved ejection fraction (HFpEF) that support the use of statins. The pleiotropic properties of statins, such as anti-inflammatory, antihypertrophic, antifibrotic, and antioxidant effects, are generally accepted and may be beneficial in HF, especially in HFpEF. Numerous observational clinical trials have consistently shown a beneficial prognostic effect of statins in patients with HFpEF, while the results of two larger trials in patients with HFrEF have been controversial. Such differences may be related to a more pronounced impact of the pleiotropic properties of statins on the pathophysiology of HFpEF and pro-inflammatory comorbidities (arterial hypertension, diabetes mellitus, obesity, chronic kidney disease) that are more common in HFpEF. This review discusses the potential mechanisms of statin action that may be beneficial for patients with HFpEF, as well as clinical trials that have evaluated the statin effects on left ventricular diastolic function and clinical outcomes in patients with HFpEF.

Açaí seed extract (ASE) rich in proanthocyanidins improves cardiovascular remodeling by increasing antioxidant response in obese high-fat diet-fed mice

Obesity is recognized as an independent risk factor for cardiovascular diseases and is an important contributor to cardiac mortality. Açaí seed extract (ASE), rich in proanthocyanidins, has been shown to have potential anti-obesity effects. This study aimed to investigate the therapeutic effect of ASE in cardiovascular remodeling associated with obesity and compare it with that of rosuvastatin. Male C57BL/6 mice were fed a high-fat diet or a standard diet for 12 weeks. The ASE (300 mg/kg/day) and rosuvastatin (20 mg/kg/day) treatments started in the 8th week until the 12th week, totaling 4 weeks of treatment. Our data showed that treatment with ASE and rosuvastatin reduced body weight, ameliorated lipid profile, and improved cardiovascular remodeling. Treatment with ASE but not rosuvastatin reduced hyperglycemia and oxidative stress by reducing immunostaining of 8-isoprostane and increasing SOD-1 and GPx expression in HFD mice. ASE and rosuvastatin reduced NOX4 expression, increased SIRT-1 and Nrf2 expression and catalase and GPx activities, and improved vascular and cardiac remodeling in HFD mice. The therapeutic effect of ASE was similar to that of rosuvastatin in reducing dyslipidemia and cardiovascular remodeling but was superior in reducing oxidative damage and hyperglycemia, suggesting that ASE was a promising natural product for the treatment of cardiovascular alterations associated with obesity.

A Review of the Molecular Mechanisms Underlying Cardiac Fibrosis and Atrial Fibrillation

The cellular and molecular mechanism involved in the pathogenesis of atrial fibrosis are highly complex. We have reviewed the literature that covers the effectors, signal transduction and physiopathogenesis concerning extracellular matrix (ECM) dysregulation and atrial fibrosis in atrial fibrillation (AF). At the molecular level: angiotensin II, transforming growth factor-β1, inflammation, and oxidative stress are particularly important for ECM dysregulation and atrial fibrotic remodelling in AF. We conclude that the Ang-II-MAPK and TGF-β1-Smad signalling pathways play a major, central role in regulating atrial fibrotic remodelling in AF. The above signalling pathways induce the expression of genes encoding profibrotic molecules (MMP, CTGF, TGF-β1). An important mechanism is also the generation of reactive oxygen species. This pathway induced by the interaction of Ang II with the AT₂R receptor and the activation of NADPH oxidase. Additionally, the interplay between cardiac MMPs and their endogenous tissue inhibitors of MMPs, is thought to be critical in atrial ECM metabolism and fibrosis. We also review recent evidence about the role of changes in the miRNAs expression in AF pathophysiology and their potential as therapeutic targets. Furthermore, keeping the balance between miRNA molecules exerting anti-/profibrotic effects is of key importance for the control of atrial fibrosis in AF.

Protective effect of Rosuvastatin on Azithromycin induced cardiotoxicity in a rat model

AIMS

Azithromycin is widely used broad spectrum antibiotic recently used in treatment protocol of COVID-19 for its antiviral and immunomodulatory effects combined with Hydroxychloroquine or alone. Rat models showed that Azithromycin produces oxidative stress, inflammation, and apoptosis of myocardial tissue. Rosuvastatin, a synthetic statin, can attenuate myocardial ischemia with antioxidant and antiapoptotic effects. This study aims to evaluate the probable protective effect of Rosuvastatin against Azithromycin induced cardiotoxicity.

MAIN METHOD

Twenty adult male albino rats were divided randomly into four groups, five rats each control, Azithromycin, Rosuvastatin, and Azithromycin +Rosuvastatin groups. Azithromycin 30 mg/kg/day and Rosuvastatin 2 mg/kg/day were administrated for two weeks by an intragastric tube. Twenty-four hours after the last dose, rats were anesthetized and the following measures were carried out; Electrocardiogram, Blood samples for Biochemical analysis of lactate dehydrogenase (LDH), and creatine phosphokinase (CPK). The animals sacrificed, hearts excised, apical part processed for H&E, immunohistochemical staining, and examined by light microscope. The remaining parts of the heart were collected for assessment of Malondialdehyde (MDA) and Reduced Glutathione (GSH).

KEY FINDINGS

The results revealed that Rosuvastatin significantly ameliorates ECG changes, biochemical, and Oxidative stress markers alterations of Azithromycin. Histological evaluation from Azithromycin group showed marked areas of degeneration, myofibers disorganization, inflammatory infiltrate, and hemorrhage. Immunohistochemical evaluation showed significant increase in both Caspase 3 and Tumor necrosis factor (TNF) immune stain. Rosuvastatin treated group showed restoration of the cardiac muscle fibers in H&E and Immunohistochemical results.

SIGNIFICANCE

We concluded that Rosuvastatin significantly ameliorates the toxic changes of Azithromycin on the heart.

DDAH-2 alleviates contrast medium iopromide-induced acute kidney injury through nitric oxide synthase

BACKGROUND

Contrast medium-induced acute kidney injury (CI-AKI) is one of the most common causes of hospital-acquired acute renal failure. However, the pathogenesis of CI-AKI remains unclear. Asymmetric dimethylarginine (ADMA) is an endogenous nitric oxide synthase (NOS) inhibitor that is largely metabolised by dimethylarginine dimethylaminohydroxylase (DDAH) in humans. Two isoforms of DDAH exist, namely, DDAH-1 and DDAH-2. In the present study, we examined whether the DDAH-2/ADMA/NOS pathway is involved in the pathogenesis of CI-AKI.

METHODS AND RESULTS

Exposure to the contrast medium iopromide led to increase in creatinine and blood urea nitrogen (BUN) levels, accumulation of ADMA, increase in reactive oxygen species (ROS) generation, and an inflammatory response in mice kidney tissue. The injection of adenovirus-harbouring DDAH-2 lowered renal ADMA levels and had a reno-protective effect against contrast-medium injury by decreasing cell apoptosis, ROS, and fibrosis. By contrast, contrast medium-induced renal injury was exacerbated in heterozygous DDAH-2 knockout mice. In the in vitro study, overexpression of DDAH-2 increased the levels of nitrite and intracellular cGMP, while the DDAH-2 knockdown induced the opposite effect. These findings were also observed in the in vivo sample.

CONCLUSIONS

Our findings provide the first evidence that the DDAH-2/ADMA/NOS pathway is involved in the pathogenesis of CI-AKI and that the protective effect of DDAH-2 probably arises from the modulation of NOS activity, oxidative stress, and the inflammatory process.

Unfolding the pleiotropic facades of rosuvastatin in therapeutic intervention of myriads of neurodegenerative disorders

Rosuvastatin, a 3-hydroxy-3-methylglutaryl-coenzyme (HMG-CoA) reductase inhibitor, and one of the most popular antihyperlipidemic medications have been found to possess pharmacodynamic activities much different from its usual indication. Recent research studies have revealed the efficacy of rosuvastatin in attenuating neuroinflammation, reducing the progression of Alzheimer's disease, providing protection against cerebral ischaemia and spinal cord injury as well as ameliorating epilepsy. Mechanisms behind the neuroprotective potential of rosuvastatin can be attributed to its pleiotropic effects, independent of its ability to inhibit HMG-CoA reductase. These processes include modulation of several cellular pathways, isoprenylation, effects on oxidative stress, nitrosative levels, inflammation, and immune response. This review aims to assimilate and summarize recent findings on the pharmacological actions of rosuvastatin in attenuating neurological disorders in order to guide future research in this space.

Youth Depression Alleviation-Augmentation with an anti-inflammatory agent (YoDA-A): protocol and rationale for a placebo-controlled randomized trial of rosuvastatin and aspirin

AIM

There is growing support for the role of inflammation and oxidative stress in the pathophysiology of major depressive disorder (MDD). This has led to the development of novel strategies targeting inflammation in the treatment of depression. Rosuvastatin and aspirin have well-documented, anti-inflammatory and antioxidant properties. The aim of the Youth Depression Alleviation: Augmentation with an anti-inflammatory agent (YoDA-A) study is to determine whether individuals receiving adjunctive anti-inflammatory agents, aspirin and rosuvastatin experience a reduction in the severity of MDD compared with individuals receiving placebo.

METHODS

YoDA-A is a 12-week triple-blind, randomized controlled trial funded by the National Health and Medical Research Council, Australia. Participants aged 15-25, with moderate-to-severe MDD, are allocated to receive either 10 mg/day rosuvastatin, 100 mg/day aspirin, or placebo, in addition to treatment as usual. Participants are assessed at baseline and at weeks 4, 8, 12 and 26. The primary outcome is change in the Montgomery-Åsberg Depression Rating Scale (MADRS) from baseline to week 12.

RESULTS

The study is planned to be completed in 2017. At date of publication, 85 participants have been recruited.

CONCLUSION

Timely and targeted intervention for youth MDD is crucial. Given the paucity of new agents to treat youth MDD, adjunctive trials are not only pragmatic and 'real-world', but additionally aim to target shortfalls in conventional medications. This study has the potential to first provide two new adjunctive treatment options for youth MDD; aspirin and rosuvastatin. Second, this study will serve as proof of principle of the role of inflammation in MDD.

Synergistic Inhibitory Effect of Rosuvastatin and Angiotensin II Type 2 Receptor Agonist on Vascular Remodeling

We investigated the possibility that coadministration of rosuvastatin and compound 21 (C21), a selective angiotensin II type 2 (AT2) receptor agonist, could exert synergistic preventive effects on vascular injury. Vascular injury was induced by polyethylene cuff placement on the femoral artery in 9-week-old male C57BL/6J mice. Mice were treated with rosuvastatin and/or with C21 after cuff placement. Neointima formation was determined 14 days after the operation and cell proliferation, and superoxide anion production and expression of inflammatory cytokines were examined 7 days after cuff placement. Neointima formation was significantly attenuated by the treatment of rosuvastatin (5 mg kg(-1) day(-1)) or C21 (10 μg kg(-1) day(-1)), associated with the decreases in proliferating cell nuclear antigen (PCNA) labeling index, oxidative stress, and the expression of inflammatory markers. Treatment with a noneffective dose of rosuvastatin (0.5 mg kg(-1) day(-1)) plus a low dose of C21 (1 μg kg(-1) day(-1)) inhibited the PCNA labeling index, superoxide anion production, mRNA expressions of NAD(P)H subunits, and mRNA and protein expressions of inflammatory markers associated with marked inhibition of neointima formation. Angiotensin II type 1 (AT1) receptor mRNA expression did not differ the groups. By contrast, AT2 receptor mRNA expression was increased by administration of C21 at the dose of 10 μg kg(-1) day(-1) but not by C21 at the dose of 1 μg kg(-1) day(-1) or rosuvastatin. The combination of rosuvastatin and AT2 receptor agonist exerted synergistic preventive effects on vascular remodeling associated with the decreases in cell proliferation, oxidative stress, and inflammatory reaction. That could be a powerful approach to vascular disease prevention.

Is rosuvastatin protective against on noise-induced oxidative stress in rat serum?

Noise, one of the main components of modern society, has become an important environmental problem. Noise is not only an irritating sound, but also a stress factor leading to serious health problems. In this study, we have investigated possible effects of rosuvastatin, a 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitor, thought to have an antioxidant effect, on noise-induced oxidative stress in the serum of rat models. Thirty-two male Wistar albino rats were used. In order to ease their adaptation, 2 weeks before the experiment, the rats were divided into four groups (with eight rats per each group): Noise exposure plus rosuvastatin usage, only noise exposure, only rosuvastatin usage and control. After the data had been collected, oxidant (Malondialdehyde, nitric oxide [NO], protein carbonyl [PC]) and antioxidant (superoxide dismutase [SOD], glutathione peroxidase [GSH-PX], catalase [CAT]) parameters were analyzed in the serum. Results indicated that SOD values were found to be significantly lower, while PC values in serum were remarkably higher in the group that was exposed to only noise. GSH-Px values in serum dramatically increased in the group on which only rosuvastatin was used. During noise exposure, the use of rosuvastatin caused significantly increased CAT values, whereas it resulted in reduced PC and NO values in serum. In conclusion, our data show that noise exposure leads to oxidative stress in rat serum; however, rosuvastatin therapy decreases the oxidative stress caused by noise exposure.

Protective effect of sitagliptin and rosuvastatin combination on vascular endothelial dysfunction in type-2 diabetes

The present investigation aimed to evaluate the protective effects of sitagliptin, glimepiride, rosuvastatin and their combinations on oxidative stress and endothelial dysfunction in the aortic tissues in fructose-fed type-2 diabetic rats. Sitagliptin (20 mg/kg, p.o.), glimepiride (2 mg/kg, p.o.), rosuvastatin (5 mg/kg, p.o.) and their combinations were administered for 6 w after induction of diabetes by fructose (66%, w/v solution, p.o. for 8 w) in wistar rats. The effects were examined on body weight, serum glucose, triglyceride, cholesterol, blood pressure, heart rate, nitric oxide and antioxidant defensive enzymes. After completion of treatment schedule, the blood pressure was determined by invasive method and vascular reactivity was tested with adrenaline, noradrenaline and phenylephrine. Endothelial dysfunction was determined by acetylcholine and sodium nitroprusside-induced vasorelaxation studies on isolated rat aortas. Long term treatments significantly decreased body weight gain, serum glucose, triglyceride and cholesterol levels; normalize the heart rate, and blood pressure in fructose fed rats. The treatments significantly improved vascular reactivity to catecholamines with reduction in elevated blood pressure in type-2 diabetic rats. The significant improvement in the relaxant response to acetylcholine and sodium nitroprusside was obtained on isolated aortas. All the treatments were effective in restoring defensive antioxidant enzymes. Sitagliptin and rosuvastatin were able to reverse endothelial dysfunction in type-2 diabetes, but better ameliorating potential was found when used in combination.

Cardiac NO signalling in the metabolic syndrome

It is well documented that metabolic syndrome (i.e. a group of risk factors, such as abdominal obesity, elevated blood pressure, elevated fasting plasma glucose, high serum triglycerides and low cholesterol level in high-density lipoprotein), which raises the risk for heart disease and diabetes, is associated with increased reactive oxygen and nitrogen species (ROS/RNS) generation. ROS/RNS can modulate cardiac NO signalling and trigger various adaptive changes in NOS and antioxidant enzyme expressions/activities. While initially these changes may represent protective mechanisms in metabolic syndrome, later with more prolonged oxidative, nitrosative and nitrative stress, these are often exhausted, eventually favouring myocardial RNS generation and decreased NO bioavailability. The increased oxidative and nitrative stress also impairs the NO-soluble guanylate cyclase (sGC) signalling pathway, limiting the ability of NO to exert its fundamental signalling roles in the heart. Enhanced ROS/RNS generation in the presence of risk factors also facilitates activation of redox-dependent transcriptional factors such as NF-κB, promoting myocardial expression of various pro-inflammatory mediators, and eventually the development of cardiac dysfunction and remodelling. While the dysregulation of NO signalling may interfere with the therapeutic efficacy of conventional drugs used in the management of metabolic syndrome, the modulation of NO signalling may also be responsible for the therapeutic benefits of already proven or recently developed treatment approaches, such as ACE inhibitors, certain β-blockers, and sGC activators. Better understanding of the above-mentioned pathological processes may ultimately lead to more successful therapeutic approaches to overcome metabolic syndrome and its pathological consequences in cardiac NO signalling.

Rosuvastatin attenuates contrast-induced nephropathy through modulation of nitric oxide, inflammatory responses, oxidative stress and apoptosis in diabetic male rats

Background

Contrast-induced nephropathy (CIN) is an important cause of acute renal failure. We observe the effect of rosuvastatin on preventing CIN in diabetic rats in current study.

Methods

Diabetic rats were then divided into five groups: 1 diabetic rats (D), 2 diabetic rats + contrast media (DCM), 3 diabetic rats + rosuvastatin (DR), 4 diabetic rats + contrast media + rosuvastatin (DRCM), 5 non-diabetic rat control (NDCM). Contrast-induced nephropathy was induced by intravenous injection a single dose of indomethacin (10 mg/kg), double doses of N-nitro-L-arginine methyl ester (10 mg/kg) and a single dose of high-osmolar contrast medium meglumine amidotrizoate (6 ml/kg). DR and DRCM group rats were treated with rosuvastatin (10 mg/kg/day) by gavage for 5 days. At the end of treatment, the experimental groups were sacrificed, and their renal tissues were investigated histopathologically beside assessments of functional activities, nitric oxide metabolites, and oxidative stress and apoptic markers.

Results

After 6 days, serum creatinine and urine microprotein were increased, and creatinine clearance, kidney nitrite were decreased in DCM rats compared with NDCM, D, DR and DRCM groups. Histopathology scores in group DCM were increased compared with groups NDCM, D and DR, but lower in group DRCM than in group DCM (p < 0.01). Kidney thiobarbituric acid-reacting substances (TBARS), serum malondialdehyde (MDA), and serum protein carbonyl content (PCC) were increased, and serum thiol was decreased in the DCM group compared with groups NDCM, D and DR; however, these results were reversed in group DRCM compared with group DCM. Both expression of IL-6, TNF-α and the percentage of apoptotic cells were increased in group DCM than in groups NDCM, D and DR, but they were decreased in group DRCM than in group DCM. The expression of phospho-p38, cleaved capase-3, and the Bax/Bcl-2 ratio, were increased in group DCM than in groups NDCM, D and DR, but were decreased in group DRCM than in group DCM.

Conclusions

Our study demonstrated that rosuvastatin treatment attenuated both inflammatory processes and apoptosis and inhibited oxidative stress and the p38 MAPK pathway in a diabetic rat model in the setting of CIN.

Putative neuroprotective agents in neuropsychiatric disorders

In many individuals with major neuropsychiatric disorders including depression, bipolar disorder and schizophrenia, their disease characteristics are consistent with a neuroprogressive illness. This includes progressive structural brain changes, cognitive and functional decline, poorer treatment response and an increasing vulnerability to relapse with chronicity. The underlying molecular mechanisms of neuroprogression are thought to include neurotrophins and regulation of neurogenesis and apoptosis, neurotransmitters, inflammatory, oxidative and nitrosative stress, mitochondrial dysfunction, cortisol and the hypothalamic-pituitary-adrenal axis, and epigenetic influences. Knowledge of the involvement of each of these pathways implies that specific agents that act on some or multiple of these pathways may thus block this cascade and have neuroprotective properties. This paper reviews the potential of the most promising of these agents, including lithium and other known psychotropics, aspirin, minocycline, statins, N-acetylcysteine, leptin and melatonin. These agents are putative neuroprotective agents for schizophrenia and mood disorders.

Ultrastructure Study of Transgenic Ren2 Rat Aorta - Part 1: Endothelium and Intima

BACKGROUND: The renin-angiotensin-aldosterone system plays an important role in the development and progression of hypertension and accelerated atherosclerosis (atheroscleropathy) associated with the cardiorenal metabolic syndrome and type 2 diabetes mellitus. Additionally, the renin-angiotensin-aldosterone system plays an important role in vascular-endothelial-intimal cellular and extracellular remodeling. METHODS: Thoracic aortas of young male transgenic heterozygous (mRen2)27 (Ren2) rats were utilized for this ultrastructural study. This lean model of hypertension, insulin resistance and oxidative stress harbors the mouse renin gene with increased local tissue (aortic) levels of angiotensin II and angiotensin type 1 receptors and elevated plasma aldosterone levels. RESULTS: The ultrastructural observations included marked endothelial cell retraction, separation, terminal nuclear lifting, adjacent duplication, apoptosis and a suggestion of endothelial progenitor cell attachment. The endothelium demonstrated increased caveolae, microparticles, depletion of Weibel-Palade bodies, loss of cell-cell and basal adhesion hemidesmosome-like structures, platelet adhesion and genesis of subendothelial neointima. CONCLUSION: These observational ultrastructural studies of the transgenic Ren2 vasculature provide an in-depth evaluation of early abnormal remodeling changes within conduit-elastic arteries under conditions of increased local levels of angiotensin II, oxidative stress, insulin resistance and hypertension.

Partial restoration of cardio-vascular defects in a rescued severe model of spinal muscular atrophy

Spinal muscular atrophy (SMA) is a leading genetic cause of infantile death. Loss of a gene called Survival Motor Neuron 1 (SMN1) and, as a result, reduced levels of the Survival Motor Neuron (SMN) protein leads to SMA development. SMA is characterized by the loss of functional motor neurons in the spinal cord. However, accumulating evidence suggests the contribution of other organs to the composite SMA phenotype and disease progression. A growing number of congenital heart defects have been identified in severe SMA patients. Consistent with the clinical cases, we have recently identified developmental and functional heart defects in two SMA mouse models, occurring at embryonic stage in a severe SMA model and shortly after birth in a less severe model (SMN∆7). Our goal was to examine the late stage cardiac abnormalities in untreated SMN∆7 mice and to determine whether gene replacement therapy restores cardiac structure/function in rescued SMN∆7 model. To reveal the extent of the cardiac structural/functional repair in the rescued mice, we analyzed the heart of untreated and treated SMN∆7 model using self-complementary Adeno-associated virus (serotype 9) expressing the full-length SMN cDNA. We examined the characteristics of the heart failure such as remodeling, fibrosis, oxidative stress, and vascular integrity in both groups. Our results clearly indicate that fibrosis, oxidative stress activation, vascular remodeling, and a significant decrease in the number of capillaries exist in the SMA heart. The cardiac structural defects were improved drastically in the rescued animals, however, the level of impairment was still significant compared to the age-matched wildtype littermates. Furthermore, functional analysis by in vivo cardiac magnetic resonance imaging (MRI) revealed that the heart of the treated SMA mice still exhibits functional defects. In conclusion, cardiac abnormalities are only partially rescued in post-birth treated SMA animals and these abnormalities may contribute to the premature death of vector-treated SMA animals with seemingly rescued motor function but an average life span of less than 70 days as reported in several studies.

Statins reverse renal inflammation and endothelial dysfunction induced by chronic high salt intake

High salt intake (HS) is a risk factor for cardiovascular and kidney disease. Indeed, HS may promote blood-pressure-independent tissue injury via inflammatory factors. The lipid-lowering 3-hydroxy 3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors exert beneficial lipid-independent effects, reducing the expression and synthesis of inflammatory factors. We hypothesized that HS impairs kidney structure and function in the absence of hypertension, and these changes are reversed by atorvastatin. Four groups of rats were treated for 6 wk in metabolic cages with their diets: normal salt (NS); HS, NS plus atorvastatin and HS plus atorvastatin. We measured basal and final body weight, urinary sodium and protein excretion (UProtV), and systolic blood pressure (SBP). At the end of the experimental period, cholesterolemia, creatinine clearance, renal vascular reactivity, glomerular volume, cortical and glomerular endothelial nitric oxide synthase (eNOS), and transforming growth factor (TGF)-β1 expression were measured. We found no differences in SBP, body weight, and cholesterolemia. HS rats had increased creatinine clearence, UProtV, and glomerular volume at the end of the study. Acetylcholine-induced vasodilatation decreased by 40.4% in HS rats ( P < 0.05). HS decreased cortical and glomerular eNOS and caused mild glomerular sclerosis, interstitial mononuclear cell infiltration, and increased cortical expression of TGF-β1. All of these salt-induced changes were reversed by atorvastatin. We conclude that long-term HS induces inflammatory and hemodynamic changes in the kidney that are independent of SBP. Atorvastatin corrected all, suggesting that the nitric oxide-oxidative stress balance plays a significant role in the earlier stages of salt induced kidney damage.

Treatment with pravastatin attenuates progression of chronic pancreatitis in rat

As appropriate therapies for pancreatic fibrosis and inflammation are limited, prognosis of chronic pancreatitis has not improved to date. Recent studies have shown that statins improve inflammation and fibrosis in several organs. We therefore examined the therapeutic effect of pravastatin on progression of chronic pancreatitis by starting this treatment after induction of pancreatic fibrosis in rats. Chronic pancreatitis was induced by continuous pancreatic ductal hypertension (PDH) for 14 days according to our previous study. Pravastatin at a dose of 10 mg/kg/day was administrated directly into the duodenum via cannula from 2 days after induction of PDH. Progression of pancreatic fibrosis and expression levels of transforming growth factor-β1 and tumor necrosis factor-α mRNA were markedly attenuated after commencement of pravastatin compared with untreated group with PDH. In addition, pravastatin treatment markedly improved pancreatic exocrine function and significantly elevated expression level of interleukin (IL)-10 and superoxide dismutase activity in the pancreas compared with the untreated group with PDH. These results revealed that pravastatin substantially attenuates the progression of pancreatic inflammation, fibrosis and exocrine dysfunction probably by its anti-oxidative property and overproduction of IL-10 in animal model of chronic pancreatitis. These results provide an experimental evidence that pravastatin exerts beneficial effect for progression of chronic pancreatitis.

Rosuvastatin attenuates the elevation in blood pressure induced by overexpression of human C-reactive protein

C-reactive protein (CRP) has been shown to function as an inflammatory factor to induce endothelial dysfunction and hypertension in rats. The anti-inflammatory effects of statins suggest that they may attenuate CRP-induced endothelial dysfunction and hypertension in Sprague-Dawley rats. Male Sprague-Dawley rats were injected with an adeno-associated virus (AAV) to induce overexpression of human CRP (AAV-hCRP) or green fluorescent protein (GFP) control (AAV-GFP). At 2 months after injection, rats were administered rosuvastatin by daily oral gavage (10 mg kg(-1)) for 2 additional months. Rosuvastatin administration attenuated the increased blood pressure and loss of vascular endothelial nitric oxide synthase expression in AAV-hCRP-treated rats, and N-nitro-L-arginine methyl ester blocked its hypotensive effect. Rosuvastatin also activated phosphoinositide 3-kinases/Akt, and inhibited Rho kinase activity in aorta. Rosuvastatin reduced the production of reactive oxygen species through downregulation of nicotinamide adenine dinucleotide phosphate oxidase subunits, p22 phox and gp91 phox, and upregulation of superoxide dismutase 1 expression. Rosuvastatin attenuated the increase in blood pressure in AAV-hCRP-treated rats through endothelial protection and antioxidant effects. Our data reveals a novel mechanism through which statins may lower blood pressure.

Olmesartan, an AT1 antagonist, attenuates oxidative stress, endoplasmic reticulum stress and cardiac inflammatory mediators in rats with heart failure induced by experimental autoimmune myocarditis

Studies have demonstrated that angiotensin II has been involved in immune and inflammatory responses which might contribute to the pathogenesis of immune-mediated diseases. Recent evidence suggests that oxidative stress may play a role in myocarditis. Here, we investigated whether olmesartan, an AT(1)R antagonist protects against experimental autoimmune myocarditis (EAM) by suppression of oxidative stress, endoplasmic reticulum (ER) stress and inflammatory cytokines. EAM was induced in Lewis rats by immunization with porcine cardiac myosin, were divided into two groups and treated with either olmesartan (10 mg/kg/day) or vehicle for a period of 21 days. Myocardial functional parameters measured by hemodynamic and echocardiographic analyses were significantly improved by the treatment with olmesartan compared with those of vehicle-treated rats. Treatment with olmesartan attenuated the myocardial mRNA expressions of proinflammatory cytokines, [Interleukin (IL)-1β, monocyte chemoattractant protein-1, tumor necrosis factor-α and interferon-γ)] and the protein expression of tumor necrosis factor-α compared with that of vehicle-treated rats. Myocardial protein expressions of AT(1)R, NADPH oxidase subunits (p47phox, p67phox, gp91phox) and the expression of markers of oxidative stress (3-nitrotyrosine and 4-hydroxy-2-nonenal), and the cardiac apoptosis were also significantly decreased by the treatment with olmesartan compared with those of vehicle-treated rats. Furthermore, olmesartan treatment down-regulated the myocardial expressions of glucose regulated protein-78, growth arrest and DNA damage-inducible gene, caspase-12, phospho-p38 mitogen-activated protein kinase (MAPK) and phospho-JNK. These findings suggest that olmesartan protects against EAM in rats, at least in part via suppression of oxidative stress, ER stress and inflammatory cytokines.

Comparative analysis of telmisartan and olmesartan on cardiac function in the transgenic (mRen2)27 rat

Telmisartan, an angiotensin receptor blocker, may have unique benefits as it possesses partial peroxisome proliferator-activated receptor (PPAR)-γ agonist activity in addition to antihypertensive effects. In this study, we test whether treatment with telmisartan ameliorates cardiovascular abnormalities to a greater extent than olmesartan, which has little PPAR-γ activity. The hypertensive rodent model of tissue renin-angiotensin system activation, transgenic (mRen2)27 (Ren2) rats and their littermate Sprague-Dawley controls were used. Rats were treated with telmisartan (2 mg · kg(-1) · day(-1)), olmesartan (2.5 mg · kg(-1) · day(-1)), or vehicle via drinking water for 3 wk; these doses achieved similar blood pressure control, as measured by telemetry. Ren2 rats displayed impaired diastolic and systolic function using left ventricular (LV) pressure-volume (P-V) analysis. Load-independent diastolic indexes, including the time constant of isovolumic relaxation and the slope of the end-diastolic P-V relationship, as well as systolic indexes, including preload recruitable stroke work, the dP/dt(max)-end-diastolic volume (EDV) relationship, and the P-V area-EDV relationship, were elevated in Ren2 rats compared with Sprague-Dawley controls (P < 0.05). The Ren2 myocardium exhibited parallel increases in the oxidant markers NADPH oxidase and 3-nitrotyrosine. The increase in the prohypertrophic protein Jak2 in Ren2 rats was associated with cardiac structural abnormalities using light microscopic and ultrastructural analysis, which included interstitial fibrosis, cardiomyocyte and LV hypertrophy, and mitochondrial derangements. Both angiotensin receptor blockers attenuate these abnormalities to a similar extent. Our data suggest that the beneficial effect of telmisartan and olmesartan on cardiac structure and function may be predominantly pressor-related or angiotensin type 1 receptor dependent in this model of renin-angiotensin system activation.

Salt-induced renal injury in spontaneously hypertensive rats: effects of nebivolol

BACKGROUND

we investigated renal effects of nebivolol, a selective β(1)-receptor blocker with additional antioxidative ability, in spontaneously hypertensive rats (SHR) where increased salt intake induces oxidative stress and worsens renal function as a result of further activation of the renin-angiotensin and sympathetic nervous systems.

METHODS

male SHR were given an 8% salt diet (HS; n = 22) for 5 weeks; their age-matched controls (n = 9) received standard chow. Nebivolol was given at a dose of 10 mg/kg/day for 5 weeks in 11 HS rats.

RESULTS

HS increased blood pressure, plasma renin concentration, urinary protein excretion, and renal nitroxidative stress while decreasing renal blood flow and angiotensin 1-7 receptor (mas) protein expression. There was no change in angiotensin II type 1 receptor expression among the experimental groups. Nebivolol did not alter the salt-induced increase in blood pressure but reduced urinary protein excretion, plasma renin concentration, and nitroxidative stress. Nebivolol also increased neuronal NOS expression while preventing the salt-induced decrease in renal blood flow and mas protein expression.

CONCLUSION

nebivolol prevented salt-induced kidney injury and associated proteinuria in SHR through a blood pressure-independent mechanism. Its protective effects may be related to reduction in oxidative stress, increases in neuronal NOS and restoration of angiotensin II type 1/mas receptor balance.

Sympathoinhibition induced by centrally administered atorvastatin is associated with alteration of NAD(P)H and Mn superoxide dismutase activity in rostral ventrolateral medulla of stroke-prone spontaneously hypertensive rats

Oxidative stress in the rostral ventrolateral medulla (RVLM) increases sympathetic nervous system activity (SNA). Oral treatment with atorvastatin decreases SNA through antioxidant effects in the RVLM of stroke-prone spontaneously hypertensive rats (SHRSP). We aimed to examine whether centrally administered atorvastain reduces SNA in SHRSP and, if so, to determine whether it is associated with the reduction of oxidative stress induced by alteration of activities of nicotinamide adenine dinucleotide phosphate [NAD(P)H] oxidase and superoxide dismutase (SOD) in the RVLM of SHRSP. SHRSP received atorvastatin (S-ATOR) or vehicle (S-VEH) by continuous intracerebroventricular infusion for 14 days. Mean blood pressure, heart rate, and SNA were significantly lower in S-ATOR than in S-VEH. Oxidative stress, Rac1 activity, NAD(P)H oxidase activity, Rac1, gp91(phox) and p22(phox) expression in the membrane fraction, and p47(phox) and p40(phox) expression in the cytosolic fraction in the RVLM were significantly lower in S-ATOR than in S-VEH. Rac1 expression in the cytosolic fraction and Mn-SOD activity, however, were significantly higher in S-ATOR than in S-VEH. Our findings suggest that centrally administered atorvastatin decreases SNA and is associated with decreasing NAD(P)H oxidase activity and upregulation of Mn-SOD activity in the RVLM of SHRSP, leading to suppressing oxidative stress.

Cardiac hypertrophy during hypercholesterolemia and its amelioration with rosuvastatin and amlodipine

Hypercholesterolemia is a common accompaniment of atherosclerosis and may be associated with cardiac hypertrophy. To define the mechanistic basis of cardiac hypertrophy in hypercholesterolemia, we fed low-density lipoprotein receptor knockout (LDLR KO) mice regular diet or high cholesterol (HC) diet for 26 weeks. There was clear evidence of cardiomyocyte hypertrophy and collagen deposition in the hearts of LDLR KO mice fed with HC diet, confirmed by histopathology (hematoxylin and eosin and Picrosirius staining) and upregulation of genes for brain natriuretic peptide, alpha-tubulin, transforming growth factor beta1, and connective tissue growth factor (CTGF). These changes were independent of change in blood pressure. The hypercholesterolemic mice hearts showed an upregulation of LOX-1, an oxidized low-density lipoprotein receptor, and angiotensin II type 1 receptor (AT1R) at messenger RNA level. In addition, there was a marked upregulation of reduced nicotinamide adenine dinucleotide phosphate (NADPH) oxidase and nuclear factor kappaB (NF-kappaB) messenger RNA, indicating overexpression of markers of oxidant stress. A separate group of LDLR KO mice were fed HC diet along with a potent 3-hydroxy-3-methylglutarylcoenzyme A reductase inhibitor rosuvastatin or a dihydropyridine calcium channel blocker amlodipine. Administration of rosuvastatin or amlodipine reduced the overexpression of genes for LOX-1 and AT1R and associated NADPH oxidase and NF-kappaB. These phenomena were associated with a marked decrease in cardiomyocyte hypertrophy and collagen deposits in and around the cardiomyocytes. In conclusion, this study provides evidence of cardiac hypertrophy and fibrosis in hypercholesterolemia independent of blood pressure change LOX-1 and AT1R act as possible signals for oxidant stress leading to alterations in cardiac structure during hypercholesterolemia. Most importantly, rosuvastatin and amlodipine ameliorate cardiomyocyte hypertrophy and fibrosis.

Practical prevention of cardiac remodeling and atrial fibrillation with full-spectrum antioxidant therapy and ancillary strategies

A wealth of research data points to increased oxidative stress as a key driver of the cardiac remodeling triggered by chronic pressure overload, loss of functional myocardial tissue, or atrial fibrillation. Oxidative stress is a mediator of the cardiomyocyte hypertrophy and apoptosis, the cardiac fibrosis, and the deficits in cardiac function which typify this syndrome, and may play a role in initiating and sustaining atrial fibrillation. Nox2- and Nox4-dependent NADPH oxidase activity appears to be a major source of this oxidative stress, and oxidants can induce conformational changes in xanthine dehydrogenase, nitric oxide synthase, and the mitochondrial respiratory chain which increase their capacity to generate superoxide as well. Consistent with these insights, various synthetic antioxidants have been shown to suppress cardiac remodeling in rodents subjected to myocardial infarction, aortic constriction, or rapid atrial pacing. It may prove feasible to achieve comparable benefits in humans through use of a "full-spectrum antioxidant therapy" (FSAT) that features a complementary array of natural antioxidants. Spirulina is a rich source of phycocyanobilin, a derivative and homolog of biliverdin that appears to mimic the potent inhibitory impact of biliverdin and free bilirubin on NADPH oxidase activity. Mega-doses of folate can markedly increase intracellular levels of tetrahydrofolates which have potent and versatile radical-scavenging activities - including efficient quenching of peroxynitrite-derived radicals Supplemental coenzyme Q10, already shown to improve heart function in clinical congestive failure, can provide important antioxidant protection to mitochondria. Phase 2 inducer nutraceuticals such as lipoic acid, administered in conjunction with N-acetylcysteine, have the potential to blunt the impact of oxidative stress by boosting myocardial levels of glutathione. While taurine can function as an antioxidant for myeloperoxidase-derived radicals, its positive inotropic effect on the failing heart seems more likely to reflect an effect on intracellular calcium dynamics. These measures could aid control of cardiac modeling less directly by lowering elevated blood pressure, or by aiding the perfusion of ischemic cardiac regions through an improvement in coronary endothelial function. Since nitric oxide functions physiologically to oppose cardiomyocyte hypertrophy and cardiac fibrosis, and is also a key regulator of blood pressure and endothelial function, cocoa flavanols - which provoke endothelial release of nitric oxide - might usefully complement the antioxidant measures recommended here.

Effect of long- and short-term treatments with pravastatin on diabetes mellitus and pancreatic fibrosis in the Otsuka-Long-Evans-Tokushima fatty rat

BACKGROUND AND PURPOSE

The effects of statins on diabetes mellitus (DM) are controversial, and their effects on pancreatic fibrosis are poorly defined. We investigated the effect of long- and short-term treatments with pravastatin on the development of DM and pancreatic fibrosis in DM-prone Otsuka-Long-Evans-Tokushima Fatty (OLETF) rats.

EXPERIMENTAL APPROACH

Male OLETF rats were divided into four groups at 12 weeks of age. The first group received a standard rat diet until the end of the experimental period at age 80 weeks. The second group was given a diet containing 0.05% pravastatin from 12 weeks of age, before the onset of DM and pancreatic fibrosis, and the third group was given the same pravastatin diet from 28 weeks of age, after the onset of DM and pancreatic fibrosis, until age 80 weeks. The fourth group received the same pravastatin diet only for 16 weeks, from 12 to 28 weeks of age, and switched to a standard diet. Progressions of DM and pancreatic fibrosis were evaluated.

KEY RESULTS

Long-term treatments with pravastatin, either from 12 or 28 weeks of age, decreased serum glucose concentration and fibrotic area, elevated superoxide dismutase activity and down-regulated transforming growth factor-beta1 mRNA in the pancreas. In contrast, after a short-term treatment with pravastatin, these parameters markedly deteriorated after its cessation.

CONCLUSIONS AND IMPLICATIONS

The results suggest that long-term treatment with pravastatin improves DM and pancreatic fibrosis via anti-oxidative and anti-fibrotic properties, whereas cessation of pravastatin abolishes these beneficial effects, and accelerates DM and pancreatic fibrosis.

An update on the lipid nephrotoxicity hypothesis

When the 'lipid nephrotoxicity hypothesis' was proposed in 1982, it brought together several disparate experimental findings in hyperlipidemia and renal disease to suggest that concomitant hyperlipidemia and proteinuria would cause self-perpetuating renal disease once the initial glomerular insult was no longer present. This process would be analogous to atherosclerosis. Since 1982, increasing evidence has supported the hypothesis that lipid abnormalities contribute to both atherosclerosis and glomerulosclerosis. In this Review, we discuss research developments that are relevant to the lipid nephrotoxicity hypothesis. We describe how inflammatory stress accompanying chronic kidney disease modifies lipid homeostasis by increasing cholesterol uptake mediated by lipoprotein receptors, inhibiting cholesterol efflux mediated by the ATP-binding cassette transporter 1 and impairing cholesterol synthesis in peripheral cells. As a result of these events, cholesterol relocates to and accumulates in renal, vascular, hepatic and possibly other tissues. The combination of increased cellular cholesterol influx and reduced efflux causes injury in some tissues and lowers the plasma cholesterol level. In addition, inflammatory stress causes a degree of statin resistance via unknown mechanisms. These phenomena alter traditional understanding of the pathogenesis of lipid-mediated renal and vascular injury and could influence the clinical evaluation of renal and cardiovascular risk and the role of lipid-lowering treatment in affected patients.

Rosuvastatin ameliorates the development of pulmonary arterial hypertension in the transgenic (mRen2)27 rat

We have recently reported that transgenic (mRen2)27 rats (Ren2 rats) exhibit pulmonary arterial hypertension (PAH), which is, in part, mediated by oxidative stress. Since 3-hydroxy-3-methylglutaryl-CoA reductase inhibitors (statins) exhibit beneficial vascular effects independent of cholesterol synthesis, we hypothesized that rosuvastatin (RSV) treatment ameliorates PAH and pulmonary vascular remodeling in Ren2 rats, in part, by reducing oxidative stress. Six-week-old male Ren2 and Sprague-Dawley rats received RSV (10 mg x kg(-1) x day(-)1 ip) or vehicle for 3 wk. After treatment, right ventricular systolic pressure (RVSP) and mean arterial pressure (MAP) were measured. To evaluate treatment effects on pulmonary arteriole remodeling, morphometric analyses were performed to quantitate medial thickening and cell proliferation, whereas whole lung samples were used to quantitate the levels of 3-nitrotyrosine, superoxide, stable nitric oxide (NO) metabolites [nitrates and nitrites (NO(x))], and expression of NO synthase isoforms. In the Ren2 rat, RVSP is normal at 5 wk of age, PAH develops between 5 and 7 wk of age, and the elevated pressure is maintained with little variation through 13 wk. At 8 wk of age, left ventricular function and blood gases were normal in the Ren2 rat. Ren2 rats exhibited elevations in medial hypertrophy due to smooth muscle cell proliferation, 3-nitrotyrosine, NO(x), NADPH oxidase activity, and endothelial NO synthase expression compared with Sprague-Dawley rats. RSV significantly blunted the increase in RVSP but did not reduce MAP in the Ren2 rat; additionally, RSV significantly attenuated the elevated parameters examined in the Ren2 rat. These data suggest that statins may be a clinically viable adjunct treatment of PAH through reducing peroxynitrite formation.

Rosuvastatin attenuates heart failure and cardiac remodelling in the ageing spontaneously hypertensive rat

3-hydroxy-3-methylglutaryl(HMG)-Coenzyme(Co)A reductase inhibitors such as rosuvastatin may improve clinical status in patients with hypertension and heart failure. The ageing spontaneously hypertensive rat (SHR) closely mimics the chronic heart failure disease process observed in humans. This study examined the structural and functional changes in the cardiovascular system of 15-month-old SHR and normotensive Wistar-Kyoto (WKY) rats treated with rosuvastatin (20 mg/kg/day perorally) for 24 weeks. Cardiovascular structure and function were monitored serially by echocardiography. At 21 months, ex vivo Langendorff, electrophysiological or histological studies were performed. Chronic rosuvastatin treatment attenuated elevations of left ventricular wet weight (mg/g body weight: 21-month WKY, 2.30 ± 0.04; 15-month SHR, 3.03 ± 0.08; 21-month SHR, 4.09 ± 0.10; 21-month SHR + rosuvastatin, 3.50 ± 0.13), myocardial extracellular matrix content (% left ventricular area: 21-month WKY, 7.6 ± 0.5; 15-month SHR, 13.2 ± 0.8; 21-month SHR 19.6 ± 1.0; 21-month SHR with rosuvastatin 14.6 ± 1.2) and diastolic stiffness (κ: 21-month WKY, 24.9 ± 0.6; 15-month SHR, 26.4 ± 0.4; 21-month SHR, 33.1 ± 0.8; 21-month SHR + rosuvastatin, 27.5 ± 0.6) as well as attenuating the deterioration of systolic and diastolic function (fractional shortening %: 21-month WKY, 66 ± 2; 15-month SHR, 51 ± 3; 21-month SHR, 38 ± 3; 21-month SHR + rosuvastatin, 52 ± 4). There was no effect on the increased systolic blood pressure, plasma low-density lipoprotein concentrations or the prolonged action potential duration. Thus, chronic rosuvastatin treatment may attenuate myocardial dysfunction in heart failure by preventing fibrosis.

Additive beneficial effects of amlodipine and atorvastatin in reversing advanced cardiac hypertrophy in elderly spontaneously hypertensive rats

1. Additive beneficial effects on cardiovascular disease have been reported for amlodipine and atorvastatin. However, it is still unclear whether the combination of amlodipine and atorvastatin has additive beneficial effects on the regression of advanced cardiac hypertrophy in hypertension. In the present study, the effects of the drug combination on advanced cardiac hypertrophy were investigated in elderly spontaneously hypertensive rats (SHR). 2. Elderly SHR (36 weeks old) were randomly allocated into four groups of 12: (i) a vehicle-treated control group; (ii) an amlodipine (10 mg/kg per day)-treated group; (iii) an atorvastatin (10 mg/kg per day)-treated group; and (iv) a group treated with a combination of amlodipine and atorvastatin (both at 10 mg/kg per day). Drugs were administered by oral gavage every morning for a period of 12 weeks before hearts were harvested for analysis. 3. Combined administration of amlodipine and atorvastatin significantly suppressed cardiomyocyte hypertrophy, interstitial fibrosis and upregulation of hypertrophic and profibrotic genes, and also improved left ventricular diastolic dysfunction to a greater extent than did amlodipine monotherapy. Further beneficial effects of combination therapy on advanced cardiac hypertrophy were associated with a greater reduction of NADPH oxidase-mediated increases in cardiac reactive oxygen species (ROS), rather than decreased blood pressure and serum cholesterol levels. 4. To elucidate the underlying molecular mechanisms, we examined cardiovascular NADPH oxidase subunits and found that amlodipine clearly attenuated the expression of p47(phox) and p40(phox) and slightly but significantly reduced p22(phox) and Rac-1 levels in heart tissue. Combination treatment with amlodipine plus atorvastatin led to a further reduction in p22(phox), p47(phox) and Rac-1 protein levels compared with amlodipine alone. 5. In conclusion, combined amlodipine and atorvastatin treatment has a greater beneficial effect on advanced cardiac hypertrophy compared with amlodipine monotherapy. The benefits are likely to be related to the additive effects of the drugs on the suppression of NADPH oxidase-mediated ROS generation.

Differential regulation of angiotensin-(1-12) in plasma and cardiac tissue in response to bilateral nephrectomy

We examined the effects of 48 h bilateral nephrectomy on plasma and cardiac tissue expression of angiotensin-(1-12) [ANG-(1-12)], ANG I, and ANG II in adult Wistar-Kyoto rats to evaluate functional changes induced by removing renal renin. The goal was to expand the evidence of ANG-(1-12) being an alternate renin-independent, angiotensin-forming substrate. Nephrectomy yielded divergent effects on circulating and cardiac angiotensins. Significant decreases in plasma ANG-(1-12), ANG I, and ANG II levels postnephrectomy accompanied increases in cardiac ANG-(1-12), ANG I, and ANG II concentrations compared with controls. Plasma ANG-(1-12) decreased 34% following nephrectomy, which accompanied 78 and 66% decreases in plasma ANG I and ANG II, respectively (P < 0.05 vs. controls). Contrastingly, cardiac ANG-(1-12) in anephric rats averaged 276 +/- 24 fmol/mg compared with 144 +/- 20 fmol/mg in controls (P < 0.005). Cardiac ANG I and ANG II values were 300 +/- 15 and 62 +/- 7 fmol/mg, respectively, in anephric rats compared with 172 +/- 8 fmol/mg for ANG I and 42 +/- 4 fmol/mg for ANG II in controls (P < 0.001). Quantitative immunofluorescence revealed significant increases in average grayscale density for cardiac tissue angiotensinogen, ANG I, ANG II, and AT(1) receptors of WKY rats postnephrectomy. Faint staining of cardiac renin, unchanged by nephrectomy, was associated with an 80% decrease in cardiac renin mRNA. These changes were accompanied by significant increases in p47(phox), Rac1, and Nox4 isoform expression. In conclusion, ANG-(1-12) may be a functional precursor for angiotensin peptide formation in the absence of circulating renin.

HMG CoA reductase inhibitors and renoprotection: the weight of the evidence

Dyslipidemia and the contributions of oxidized low-density lipoproteins (ox-LDL) are independent cardiovascular risk factors. There is growing evidence that dyslipidemia contributes not only to cardiovascular disease but also to the progressive decline of renal function in diabetic and non-diabetic kidney disease. Ox-LDL, by generating inflammation and oxidative stress, contributes to a pro-atherogenic mileu and leads to endothelial dysfunction, subsequent glomerular filtration barrier damage, and progressive renal injury. Chronic kidney disease (CKD), in turn, induces deleterious effects on lipid metabolism. Therefore, by inhibiting cholesterol synthesis and reducing ox-LDL, HMG CoA reductase inhibitors (statins) are attractive therapeutic options to preserve renal function. Current evidence demonstrates a reduction in cardiovascular risk and improved renal outcomes especially in patients with mild to moderate impairment of renal function. Evidence supports a beneficial role of statins thought to extend beyond their lipid-lowering effect, referred to as pleiotropic actions. These actions include modulatory effects on inflammation, oxidative stress and thrombosis, derived from their ability to prevent the formation of isoprenoid intermediates involved in cellular signaling, posttranslational modification of proteins and cellular function. This translates to potential reductions in the rate of decline in GFR in CKD and adverse effects of type 2 diabetes mellitus in the kidney. This review examines the role of statins for reno-protection as well as cardiovascular benefit in patients with CKD.

Cardioprotective effects of pitavastatin on cardiac performance and remodeling in failing rat hearts

BACKGROUND

Activation of phosphatidylinositol 3-kinase (PI3K)-Akt signaling by statins increases the activity of endothelial nitric oxide synthase (eNOS). We investigate whether statins (pitavastatin) improve cardiac function and remodeling via eNOS production associated with the PI3K-Akt signaling pathway, Rho-kinase (ROCK) pathway, and the development of oxidative stress in Dahl salt-sensitive (DS) hypertensive rats with heart failure (DSHF).

METHODS

Pitavastatin (3 mg/kg per day), or pitavastatin plus specific PI3K inhibitor, wortmannin (1 mg/kg per day), or wortmannin alone were administered from the age of 11-18 weeks. Age-matched male Dahl salt-resistant (DR) rats served as a control group.

RESULTS

Decreased end-systolic elastance (Ees) and percent fractional shortening (%FS) in failing rats was significantly ameliorated by pitavastatin, but not pitavastatin plus wortmannin or wortmannin alone. Upregulation of eNOS and Akt phosphorylation by pitavastatin was suppressed by pitavastatin plus wortmannin or wortmannin alone. Pitavastatin effectively inhibited the vascular lesion formation such as medial thickness and perivascular fibrosis, but not pitavastatin plus wortmannin or wortmannin alone. Activated RhoA and myosin light chain phosphorylation and RhoA, ROCK expression was inhibited by pitavastatin or a specific ROCK inhibitor, Y-27632, and downregulated eNOS expression and Akt phosphorylation was ameliorated by Y-27632. Increased expression of NAD(P)H oxidase subunits and activated p65 nuclear factor (NF)-kappaB, p44/p42 extracellular signal-regulated kinases and its downstream effector p90 ribosomal S6 kinase phosphorylation in failing rat hearts was inhibited by pitavastatin.

CONCLUSIONS

These findings suggest that pitavastatin may improve cardiac function and remodeling via eNOS production associated with the PI3K-Akt signaling pathway, the ROCK pathway and oxidative stress.

Renin inhibition attenuates insulin resistance, oxidative stress, and pancreatic remodeling in the transgenic Ren2 rat

Emerging evidence indicates that pancreatic tissue expresses all components of the renin-angiotensin system. However, the functional role is not well understood. This investigation examined renin inhibition on pancreas structure/function in the transgenic Ren2 rat harboring the mouse renin gene, a model of tissue renin overexpression. Renin is the rate-limiting step in the generation of angiotensin II (Ang II), which stimulates the generation of reactive oxygen species in a variety of tissues. Overexpression of renin in Ren2 rats results in hypertension, insulin resistance, and cardiovascular and renal damage. Young (6-7 wk old) insulin-resistant male Ren2 and age-matched insulin sensitive Sprague Dawley rats were treated with the renin inhibitor, aliskiren (50 mg/kg.d by ip injection), or placebo for 21 d. At 21 d, the Ren2 demonstrated insulin resistance with increased islet insulin, Ang II, and reduced total insulin receptor substrate (IRS)-1, IRS-2, and Akt immunostaining. There was increased islet nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activity and subunits (p47(phox) and Rac1) as well as increased nitrotyrosine immunostaining (each P < 0.05). These functional abnormalities were associated with a disordered islet architecture; increased islet-exocrine interface, pericapillary fibrosis, and structurally abnormal mitochondria and content in endocrine and exocrine pancreas. In vivo treatment with aliskiren normalized systemic insulin resistance and islet insulin, Ang II, NADPH oxidase activity/subunits, and nitrotyrosine and improved total IRS-1 and Akt phosphorylation (each P < 0.05) as well as islet/exocrine structural abnormalities. Collectively, these data suggest that pancreatic functional/structural changes are driven, in part, by tissue renin-angiotensin system-mediated increases in NADPH oxidase and reactive oxygen species generation, abnormalities attenuated with direct renin inhibition.

Ultrastructure of islet microcirculation, pericytes and the islet exocrine interface in the HIP rat model of diabetes

CONTEXT

The transgenic human islet amyloid polypeptide (HIP) rat model of type 2 diabetes mellitus (T2DM) parallels the functional and structural changes in human islets with T2DM.

OBJECTIVE

The transmission electron microscope (TEM) was utilized to observe the ultrastructural changes in islet microcirculation.

METHODS

Pancreatic tissue from male Sprague Dawley rats (2, 4, 8, 14 months) were used as controls (SDC) and compared to the 2-, 4-, 8- and 14-month-old HIP rat models.

RESULTS

The 2-month-old HIP model demonstrated no islet or microcirculation remodeling changes when compared to the SDC models. The 4-month-old HIP model demonstrated significant pericapillary amyloid deposition and diminution of pericyte foot processes as compared to the SDC models. The 8-month-old model demonstrated extensive islet amyloid deposition associated with pericyte and beta-cell apoptosis when compared with SDC. The 14-month-old HIP model demonstrated a marked reduction of beta-cells and intra-islet capillaries with near complete replacement of islets by amyloidoses. Increased cellularity in the region of the islet exocrine interface was noted in the 4- to 14-month-old HIP models as compared to SDC. In contrast to intra-islet capillary rarefaction there was noticeable angiogenesis in the islet exocrine interface. Pericytes seemed to be closely associated with collagenosis, intra-islet adipogenesis and angiogenesis in the islet exocrine interface.

CONCLUSION

The above novel findings regarding the microcirculation and pericytes could assist researchers and clinicians in a better morphological understanding of T2DM and lead to new strategies for prevention and treatment of T2DM.

Effect of renin inhibition and AT1R blockade on myocardial remodeling in the transgenic Ren2 rat

Angiotensin II (Ang II) stimulation of the Ang type 1 receptor (AT(1)R) facilitates myocardial remodeling through NADPH oxidase-mediated generation of oxidative stress. Components of the renin-angiotensin system constitute an autocrine/paracrine unit in the myocardium, including renin, which is the rate-limiting step in the generation of Ang II. This investigation sought to determine whether cardiac oxidative stress and cellular remodeling could be attenuated by in vivo renin inhibition and/or AT(1)R blockade in a rodent model of chronically elevated tissue Ang II levels, the transgenic (mRen2)27 rat (Ren2). The Ren2 overexpresses the mouse renin transgene with resultant hypertension, insulin resistance, and cardiovascular damage. Young (6- to 7-wk-old) heterozygous (+/-) male Ren2 and age-matched Sprague-Dawley rats were treated with the renin inhibitor aliskiren, which has high preferential affinity for human and mouse renin, an AT(1)R blocker, irbesartan, or placebo for 3 wk. Myocardial NADPH oxidase activity and immunostaining for NADPH oxidase subunits and 3-nitrotyrosine were evaluated and remodeling changes assessed by light and transmission electron microscopy. Blood pressure, myocardial NADPH oxidase activity and subunit immunostaining, 3-nitrotyrosine, perivascular fibrosis, mitochondrial content, and markers of activity were significantly increased in Ren2 compared with SD littermates. Both renin inhibition and blockade of the AT(1)R significantly attenuated cardiac functional and structural alterations, although irbesartan treatment resulted in greater reductions of both blood pressure and markers of oxidative stress. Collectively, these data suggest that both reduce changes driven, in part, by Ang II-mediated increases in NADPH oxidase and, in part, increases in blood pressure.

Chronic kidney disease as a cardiovascular risk state and considerations for the use of statins

Chronic kidney disease (CKD) creates one of the highest risk atherosclerotic states that can occur in human beings. The use of 3-hydroxy-3-methylglutaryl coenzyme reductase inhibitors (statins) has gained widespread acceptance in the general population for the purposes of lowering low-density lipoprotein cholesterol (LDL-C) and reducing the future risks of myocardial infarction, stroke, and cardiac death. In patients with CKD, the balance of benefits and risks of statins appears to be different than that in the general population. Reductions in LDL-C with statins may be associated with a reduced progression of CKD. Importantly, recent studies suggest statins are associated with a reduction in rates of acute kidney injury, mediated by ischemic insults and oxidative stress, after cardiac surgery and exposure to iodinated contrast. A reduction in cardiovascular events with LDL-C reduction in CKD and dialysis patients is yet to be proven. In addition, studies suggest that there are higher adverse drug effects with statins in CKD. This work will address the benefits and risks of this important treatment option for the growing population of patients with CKD, who have not undergone renal transplantation, and are at very high risk of cardiovascular events.

NOX enzymes as novel targets for drug development

The members of the NOX/DUOX family of NADPH oxidases mediate such physiologic functions as host defense, cell signaling, and thyroid hormone biosynthesis through the generation of reactive oxygen species (ROS), including superoxide anion and hydrogen peroxide. Moreover, ROS are involved in a broad range of fundamental biochemical and cellular processes, and data accumulated in recent years indicate that the NOX enzymes comprise one of the most important biological sources of ROS. Given the high biochemical reactivity of ROS, it is not surprising that they have been implicated in a wide variety of pathologies and diseases. Prominent among the settings that feature ROS-mediated tissue injury are disorders associated with inflammation, aging, and progressive degenerative changes in cells and organ systems, and it appears that essentially no organ system is exempt. Among the disorders currently believed to be mediated at least in part by NOX-derived ROS are hypertension, aortic aneurysm, myocardial infarction (and other ischemia-reperfusion disorders), pulmonary fibrosis and hypertension, amyotropic lateral sclerosis, Alzheimer's disease, Parkinson's disease, ischemic stroke, diabetic nephropathy, and renal cell carcinoma. Several small-molecule and peptide inhibitors of the NOX enzymes have been useful in experimental studies, but issues of specificity, potency, and toxicity militate against any of the existing published compounds as candidates for drug development. Given the broad array of disease targets documented in recent work, the time is here for vigorous efforts to develop clinically useful inhibitors of the NOX enzymes. As most (though not all) NOX-related diseases appear to be mediated by a single member of the NOX family, agents with isoform specificity will be preferred, although broadly active NOX inhibitors may prove to be useful in some settings.

An overview of the extra-lipid effects of rosuvastatin

Statins, in addition to their beneficial lipid modulation effects, exert a variety of several so-called "pleiotropic" actions that may result in clinical benefits. Rosuvastatin, the last agent of the class to be introduced, has proved remarkably potent in reducing low-density lipoprotein cholesterol levels. At present, no large-scale primary or secondary prevention clinical trials document either its long-term safety or its effectiveness in preventing cardiovascular events. A substantial number of experimental and clinical studies have indicate favorable effects of rosuvastatin on endothelial function, oxidized low-density lipoprotein, inflammation, plaque stability, vascular remodeling, hemostasis, cardiac muscle, and components of the nervous system. Available data regarding the effects of rosuvastatin on renal function and urine protein excretion do not seem to raise any safety concerns. Whether the established "pleiotropy" and/or lipid-lowering efficacy of rosuvastatin may translate into reduced morbidity and mortality remains to be shown in ongoing clinical outcome trials.