Protective effect of HMG-CoA reductase inhibitor on experimental renal ischemia-reperfusion injury

Prevalence and mortality of transient acute kidney injury within 48 h, as new subtype, following coronary angiography: a cohort study

BACKGROUND

The association of transient acute kidney injury (AKI) with mortality was controversial. Our study aims to investigate the prevalence and impact of transient AKI on mortality in patients following coronary angiography (CAG).

METHODS

Our study retrospectively enrolled 3970 patients with pre-operative serum creatinine (Scr) and twice measurements within 48 h after procedure. Transient AKI defined as the diagnosis of AKI (Scr > 0.3 mg/dL or > 50% from the baseline level) on day 1 when Scr failed to meet the criteria for AKI on the day 2. Maintained AKI was defined as AKI not meeting the definition for transient AKI. The primary outcome was 1-year all-cause mortality. Multivariable logistic regression was used to assess the association between transient AKI and 1-year mortality.

RESULTS

Among 3,970 participants, 861 (21.7%) occurred AKI, of whom 128 (14.9%) was transient AKI and 733 (85.1%) was maintained AKI. 312 (7.9%) patients died within 1-year after admission. After multivariable analysis, transient AKI was not associated with higher 1-year mortality [adjusted odds ratio (aOR), 1.37; CI 0.68-2.51] compared without AKI. Among AKI patients, transient AKI was associated with a 52% lower 1-year mortality compared with maintained AKI. Additionally, maintained AKI was significantly associated with higher 1-year mortality (aOR, 2.67; CI 2.05-3.47).

CONCLUSIONS

Our data suggested that transient AKI within 48 h was a common subtype of AKI following CAG, without increasing mortality. More attention needs to be paid to the patients suffering from maintained AKI following CAG.

Protective Effect of Hydroalcoholic Extract of Stachys pilifera on Oxidant-Antioxidant Status in Renal Ischemia/Reperfusion Injuries in Male Rats

Background

Renal ischemia-reperfusion (I/R) has a pivotal role in the progression of acute renal failure. Reactive oxygen species are considered the major constituents involved in the biochemical and pathophysiological changes that were shown during kidney I/R. The purpose of this study was to examine the renoprotective effects of Stachys pilifera ethanolic extract on oxidant-antioxidant status in renal I/R-injuries in male rats. Material and methods. Twenty-one male Wistar rats were arbitrarily distributed into 3 groups: sham control (SC), I/R, and I/R + Stachys pilifera ethanolic extract (500 mg/kg). The artery and vein of the right kidney were completely blocked, and the right kidney was completely removed in all groups. Then, the left kidney artery was blocked with suture thread for 30 minutes in only I/R and I/R + SP extract groups. Kidney function indices, oxidative stress markers, and hematoxylin and eosin staining were investigated in the plasma and kidney tissues.

Results

It was shown that the urine Na and K, fractional excretion of Na and K, and protein carbonyl content markedly increased in the merely I/R group as compared to SC rats, while the administration of SP extract markedly reduced these indices (P < 0.05). Also, glomerular filtration rate and total thiol meaningfully reduced in the I/R rats in contrast to the SC group, while the treatment with SP extract markedly augmented these indices (P < 0.05). However, in agreement with renal function tests, SP extract had no significant effects on histopathological examinations.

Conclusion

It seems that SP extract employs renoprotective effects on renal damage induced by I/R, possibly by improving of oxidant-antioxidant status in favor of the antioxidant system.

A randomized unblinded trial to compare effects of intensive versus conventional lipid-lowering therapy in patients undergoing renal artery stenting

BACKGROUND

Although current guidelines recommend the use of statins for severe atherosclerotic renal artery stenosis (ARAS), the renal protection of intensive lipid-lowering therapy in patients with ARAS who underwent stent placement remains uncertain. The aim of this study was to compare the renal-protective effect of intensive lipid lowering with that of conventional lipid lowering in patients with ARAS undergoing stent placement.

METHODS

A total 150 patients with severe ARAS undergoing stent placement were randomly (1:1) assigned to receive intensive lipid lowering [target low-density lipoprotein cholesterol (LDL-C) <70mg/dL] or conventional lipid lowering (target LDL-C ≥70mg/dL, <128mg/dL). All patients received rosuvastatin. We adjusted LDL-C to the goal within two months after renal stenting and maintained stability. The primary endpoint was the change in estimated glomerular filtration rate (eGFR) at 12 months.

RESULTS

During the study period, LDL-C was lower in the patients with intensive lipid lowering than with conventional lipid lowering (at 12 months 58.0±11.6 vs 85.1±15.5mg/dL, p<0.001). At 12-month follow-up, eGFR (91.8±30.2 vs 78.5±19.5)mL/min·1.73m², p=0.002) and the increase in eGFR compared to baseline [14.8(IQR, 4.1, 26.7) vs -0.4(IQR, -9.5, 8.0)mL/min·1.73m², p<0.001] were higher in the patients with intensive lipid lowering than with conventional lipid lowering. Urinary albumin-creatinine ratio [42.2(IQR, 20.0, 60.9) vs 60.8(IQR, 26.8, 121.6)mg/g, p=0.032] was lower and the decrease in urinary albumin-creatinine ratio compared to baseline [27.4(IQR, 3.0, 53.8) vs -3.1(IQR, -17.3, 30.9)mg/g, p=0.001] was higher in the patients with intensive lipid lowering than with conventional lipid lowering. The restenosis rate (3.1% vs 3.4%, p=0.711) and major clinical events (6.8% vs 11.0%, p=0.37) were similar between the two groups.

CONCLUSIONS

In patients with severe ARAS undergoing stent placement, intensive lipid lowering showed significant benefits in renal protection over conventional lipid-lowering therapy.

HMG-CoA reductase inhibitors (statins) and acute kidney injury: A secondary analysis of renal study outcomes

BACKGROUND

Mortality in intensive care unit (ICU) patients with acute kidney injury (AKI) remains high. Previous studies have explored the role of HMG-CoA reductase inhibitors (statins) with variable findings.

METHODS

The Randomized Evaluation of Normal versus Augmented Level Replacement Therapy (RENAL) Study recruited 1508 participants requiring dialysis in ICU between 2006 and 2009. Statin use was recorded at study baseline. Multivariate Cox modelling was used to assess associations of such statin use and all-cause mortality. Propensity score analysis was performed for sensitivity analysis. The primary outcome was all-cause mortality at 90 days.

RESULTS

Of the 1462 participants with the available data on statin usage, 187 (12.8%) received statin therapy at baseline. Participants who receiving statins were older (P < 0.001), less likely to have sepsis or require mechanical ventilation (P < 0.001). Multivariable analysis showed statin use did not have significant associations with mortality at both day 28 (hazard ratio (HR) = 1.053, 95% confidence interval (CI) = 0.784-1.415, P = 0.730) and day 90 (HR = 1.091, 95% CI = 0.836-1.424, P = 0.520). Propensity score analysis confirmed the lack of association between statin use and mortality at day 90 (HR = 1.042, 95% CI = 0.734-1.479, P = 0.819). However, in septic patients, multivariable analysis suggested statin therapy was associated with a trend to higher mortality at day 90 (HR = 1.688, 95% CI = 1.132-2.519, P = 0.010) and continuation of statins was associated with higher mortality (HR = 2.160, 95% CI = 1.296-3.599, P = 0.003), compared with statin withdrawal.

CONCLUSION

In the RENAL study cohort, baseline statin use was not associated with mortality. Our findings do not support a protective role of statins in ICU patients with severe AKI. Clinical Trials registration number for the RENAL study: NCT00221013, the date of registration: September 14, 2005.

Rosuvastatin Alleviates Ischemia/Reperfusion Injury in Cardiomyocytes by Downregulating Hsa-miR-24-3p to Target Upregulated Uncoupling Protein 2

Statins could reduce the risks of coronary heart disease death and ischemic cardiovascular events. In this study, we aim to explore the role of rosuvastatin in ischemia/reperfusion (I/R)-injured cardiomyocytes and the possible mechanism. An I/R model was established by oxygen-glucose deprivation/reperfusion (OGD/R). The protective effects of rosuvastatin pretreatment on OGD/R-injured cardiomyocytes were performed using MTT assay, lactate dehydrogenase (LDH) release assay, and quantitative real-time polymerase chain reaction (qRT-PCR). Bioinformatics software TargetScan and miRTarBase were used to predict the targeted miRNAs with uncoupling protein (UCP)2. Furthermore, verify the binding capacity of hsa-miR-24-3p and UCP2 with qRT-PCR and dual-luciferase reporter assay. The expression of UCP2, cell viability, LDH level, and apoptosis level affected by downregulated hsa-miR-24-3p were assessed using qRT-PCR, western blotting, MTT, the LDH kit, and flow cytometry. Pretreatment with rosuvastatin could significantly augment cell viability, reduce LDH level, increase the expression of UCP2, and downregulate hsa-miR-24-3p in OGD/R-injured H9c2 cells. miR-24-3p was closely connected with UCP2, and downregulated miR-24-3p could promote UCP2 expression, which presented cell viability increasing, LDH release and cell apoptosis inhibition in OGD/R condition. Moreover, it decreased the protein expression of Cleaved-Caspase-9 and Cyto C. This is the first time our study suggests that rosuvastatin pretreatment protects cardiomyocytes from OGD/R through upregulating UCP2 through downregulation of hsa-miR-24-3p.

Improvement in Renal Function and Reduction in Serum Uric Acid with Intensive Statin Therapy in Older Patients: A Post Hoc Analysis of the SAGE Trial

Background

Improvement in renal function and decreases in serum uric acid (SUA) have been reported following prolonged high-intensity statin (HMG-CoA reductase inhibitor) therapy. This post hoc analysis of the SAGE trial examined the effect of intensive versus less intensive statin therapy on renal function, safety, and laboratory parameters, including SUA, in elderly coronary artery disease (CAD) patients (65–85 years) with or without chronic kidney disease (CKD).

Methods

Patients were randomized to atorvastatin 80 mg/day or pravastatin 40 mg/day and treated for 12 months. Patients were stratified using Modification of Diet in Renal Disease (MDRD) estimated glomerular filtration rates (eGFRs) in CKD (eGFR <60 mL/min/1.73 m²) and non-CKD populations.

Results

Of the 893 patients randomized, 858 had complete renal data and 418 of 858 (49 %) had CKD (99 % Stage 3). Over 12 months, eGFR increased with atorvastatin and remained stable with pravastatin (+2.38 vs. +0.18 mL/min/1.73 m², respectively; p < 0.0001). MDRD eGFR improved significantly in both CKD treatment arms; however, the increased eGFR in patients without CKD was significantly greater with atorvastatin (+2.08 mL/min/1.73 m²) than with pravastatin (−1.04 mL/min/1.73 m²). Modest reductions in SUA were observed in both treatment arms, but a greater fall occurred with atorvastatin than with pravastatin (−0.52 vs. −0.09 mg/dL, p < 0.0001). Change in SUA correlated negatively with changes in eGFR and positively with changes in low-density lipoprotein cholesterol. Reports of myalgia were rare (3.6 % CKD; 5.7 % non-CKD), and there were no episodes of rhabdomyolysis. Elevated serum alanine and aspartate transaminase to >3 times the upper limit of normal occurred in 4.4 % of atorvastatin- and 0.2 % of pravastatin-treated patients.

Conclusion

Intensive management of dyslipidemia in older patients with stable coronary heart disease may have beneficial effects on renal function and SUA.

HMG CoA reductase inhibitors (statins) for preventing acute kidney injury after surgical procedures requiring cardiac bypass

BACKGROUND

Acute kidney injury (AKI) is common in patients undergoing cardiac surgery among whom it is associated with poor outcomes, prolonged hospital stays and increased mortality. Statin drugs can produce more than one effect independent of their lipid lowering effect, and may improve kidney injury through inhibition of postoperative inflammatory responses.

OBJECTIVES

This review aimed to look at the evidence supporting the benefits of perioperative statins for AKI prevention in hospitalised adults after surgery who require cardiac bypass. The main objectives were to 1) determine whether use of statins was associated with preventing AKI development; 2) determine whether use of statins was associated with reductions in in-hospital mortality; 3) determine whether use of statins was associated with reduced need for RRT; and 4) determine any adverse effects associated with the use of statins.

SEARCH METHODS

We searched the Cochrane Renal Group's Specialised Register to 13 January 2015 through contact with the Trials' Search Co-ordinator using search terms relevant to this review.

SELECTION CRITERIA

Randomised controlled trials (RCTs) that compared administration of statin therapy with placebo or standard clinical care in adult patients undergoing surgery requiring cardiopulmonary bypass and reporting AKI, serum creatinine (SCr) or need for renal replacement therapy (RRT) as an outcome were eligible for inclusion. All forms and dosages of statins in conjunction with any duration of pre-operative therapy were considered for inclusion in this review.

DATA COLLECTION AND ANALYSIS

All authors extracted data independently and assessments were cross-checked by a second author. Likewise, assessment of study risk of bias was initially conducted by one author and then by a second author to ensure accuracy. Disagreements were arbitrated among authors until consensus was reached. Authors from two of the included studies provided additional data surrounding post-operative SCr as well as need for RRT. Meta-analyses were used to assess the outcomes of AKI, SCr and mortality rate. Data for the outcomes of RRT and adverse effects were not pooled. Adverse effects taken into account were those reported by the authors of included studies.

MAIN RESULTS

We included seven studies (662 participants) in this review. All except one study was assessed as being at high risk of bias. Three studies assessed atorvastatin, three assessed simvastatin and one investigated rosuvastatin. All studies collected data during the immediate perioperative period only; data collection to hospital discharge and postoperative biochemical data collection ranged from 24 hours to 7 days. Overall, pre-operative statin treatment was not associated with a reduction in postoperative AKI, need for RRT, or mortality. Only two studies (195 participants) reported postoperative SCr level. In those studies, patients allocated to receive statins had lower postoperative SCr concentrations compared with those allocated to no drug treatment/placebo (MD 21.2 µmol/L, 95% CI -31.1 to -11.1). Adverse effects were adequately reported in only one study; no difference was found between the statin group compared to placebo.

AUTHORS' CONCLUSIONS

Analysis of currently available data did not suggest that preoperative statin use is associated with decreased incidence of AKI in adults after surgery who required cardiac bypass. Although a significant reduction in SCr was seen postoperatively in people treated with statins, this result was driven by results from a single study, where SCr was considered as a secondary outcome. The results of the meta-analysis should be interpreted with caution; few studies were included in subgroup analyses, and significant differences in methodology exist among the included studies. Large high quality RCTs are required to establish the safety and efficacy of statins to prevent AKI after cardiac surgery.

5-Lypoxygenase products are involved in renal tubulointerstitial injury induced by albumin overload in proximal tubules in mice

The role of albumin overload in proximal tubules (PT) in the development of tubulointerstitial injury and, consequently, in the progression of renal disease has become more relevant in recent years. Despite the importance of leukotrienes (LTs) in renal disease, little is known about their role in tubulointerstitial injury. The aim of the present work was to investigate the possible role of LTs on tubulointerstitial injury induced by albumin overload. An animal model of tubulointerstitial injury challenged by bovine serum albumin was developed in SV129 mice (wild-type) and 5-lipoxygenase-deficient mice (5-LO^–/–). The changes in glomerular morphology and nestin expression observed in wild-type mice subjected to kidney insult were also observed in 5-LO^–/– mice. The levels of urinary protein observed in the 5-LO^–/– mice subjected or not to kidney insult were lower than those observed in respective wild-type mice. Furthermore, the increase in lactate dehydrogenase activity, a marker of tubule damage, observed in wild-type mice subjected to kidney insult did not occur in 5-LO^–/– mice. LTB₄ and LTD₄, 5-LO products, decreased the uptake of albumin in LLC-PK1 cells, a well-characterized porcine PT cell line. This effect correlated with activation of protein kinase C and inhibition of protein kinase B. The level of proinflammatory cytokines, tumor necrosis factor-α and interleukin (IL)-6, increased in mice subjected to kidney insult but this effect was not modified in 5-LO^–/– mice. However, 5-LO^–/– mice subjected to kidney insult presented lower macrophage infiltration and higher levels of IL-10 than wild-type mice. Our results reveal that LTs have an important role in tubulointerstitial disease induced by albumin overload.

Effects of statins on ischemia-reperfusion complications in breast free flaps

BACKGROUND

Administration of statins or other cardiovascular medications (CVMs) could potentially protect against the development of ischemia-reperfusion (I/R) injury in free flap reconstruction. The aim of this study was to examine whether the use of statins and other CVMs decreased the rate of I/R injury in autologous free flap breast reconstruction.

METHODS

Retrospective chart review was performed on women who had undergone mastectomy and autologous free flap breast reconstruction between 2004 and 2010. Patient characteristics, use of statin and/or CVMs, and I/R-related complications were ascertained. Multivariable logistic regression was used to identify associations between independent risk factors and specific complications.

RESULTS

There were 702 free flap breast reconstructions included in this study; 45 performed in patients on statins, 70 in patients on CVMs, and 38 in patients on both. Overall complication rate in patients on statins and patients on CVMs was significantly higher than those not on any medication (46.7% versus 31.5%, P=0.037 and 45.7% versus 31.5%, P=0.017, respectively). When I/R complications were pooled, there were no significant differences between patients not on any medications and those on statins (P=0.26), CVMs (P=0.18), and both (P=0.83.)

CONCLUSIONS

Although there may be theoretical pharmacologic benefits of statins and/or CVMs to reduce the incidence of IR injury in autologous free flap breast reconstruction, the results of this study showed no clear advantages when these drugs were used.

Atorvastatin treatment attenuates renal injury in an experimental model of ischemia-reperfusion in rats

BACKGROUND

Recent studies in animal models have shown that statins can protect against renal failure independent of their lipid-lowering actions, and there is also an association between statin use and improved renal function after suprarenal aortic clamping. We investigated the hypothesis that post-ischemic acute renal failure could be ameliorated with atorvastatin (ATO) treatment and the possible molecular mechanisms in a model of ischemia-reperfusion (IR) in rats.

METHODS

Twenty-four male Sprague-Dawley rats were divided into three groups: sham, IR, and IR + ATO. ATO was given by a single intraperitoneal injection (10 mg/kg) 30 min before reperfusion in the IR + ATO group. The IR group and sham group received saline vehicle via the intraperitoneal route.

RESULTS

After 24 h of IR, serum creatinine levels were increased in the IR group compared with the sham group (p < 0.001). ATO treatment reduced the elevation of serum creatinine level by 18% (p < 0.05) and significantly increased the creatinine clearance rate (p < 0.001). Concentrations of advanced oxidation protein products and malondialdehyde were reduced in the ATO group, approaching levels observed in sham-group rats. ATO treatment alleviated pathological changes in renal tubular cells. Protein and mRNA levels of intercellular adhesion molecule-1 and monocyte chemotactic protein-1 were reduced significantly.

CONCLUSIONS

These data suggest that direct protection of injured kidneys by ATO was possible even though the drug was injected 30 min before reperfusion, and that ATO may reduce IR injury by anti-inflammatory effects and by reducing oxidation stress.

Podocytes express IL-6 and lipocalin 2/ neutrophil gelatinase-associated lipocalin in lipopolysaccharide-induced acute glomerular injury

Background/Aims

Acute kidney injury (AKI) contributes to significant morbidity and mortality in the intensive care unit (ICU). Plasma levels of interleukin (IL)-6 predict the development of AKI and are associated with higher mortality in ICU patients with AKI. Most studies in AKI have focused on the tubulo-interstitium, despite evidence of glomerular involvement. In the following study, our goals were to investigate the expression of IL-6 and its downstream mediators in septic-induced AKI.

Methods

Podocytes were treated in vitro with lipopolysaccharide (LPS) and mice were treated with LPS, and we evaluated IL-6 expression by real-time PCR, ELISA and in situ RNA hybridization.

Results

Following LPS stimulation, IL-6 is rapidly and highly induced in cultured podocytes and in vivo in glomeruli and infiltrating leukocytes. Surprisingly, in direct response to exogenous IL-6, podocytes produce lipocalin-2/neutrophil gelatinase-associated lipocalin (Lcn2/Ngal). LPS also potently induces Lcn2/Ngal expression in podocytes in culture and in glomeruli in vivo. Intense Lcn2/Ngal expression is also observed in IL-6 knockout mice, suggesting that while IL-6 may be sufficient to induce glomerular Lcn2/Ngal expression, it is not essential.

Conclusions

The glomerulus is involved in septic AKI, and we demonstrate that podocytes secrete key mediators of AKI including IL-6 and Lcn2/Ngal.

Role of endogenous vitamin E in renal ischemic preconditioning process: differences between male and female rats

BACKGROUND

Antioxidants such as α-tocopherol (vitamin E) and β-carotene (vitamin A) play an important role in protective effect of repeated brief periods of ischemia, namely ischemic preconditioning (IPC). Values of these antioxidants were investigated and compared after induction of ischemia reperfusion (IR) and kidney IPC in both male and female rats.

METHODS

Forty eight Wistar rats were divided randomly into six groups of 8: groups A and B (male and female controls, respectively), group C (male IR or IR cases), group D (female IR cases) and groups E and F (male and female IPC cases, respectively). In groups C and D, ischemia was induced by clamping of left renal arteries for 45 min. In groups E and F, rats underwent four cycles of 4 min of arterial clamping and 11 min of de-clamping before final 45 min ischemia induction. Afterward, serum was collected to assess the blood urea nitrogen, creatinine and vitamins E and A values. Renal tissues were obtained for histological assessments.

RESULTS

α-tocopherol levels in male and female rats showed a significant increase in IPC compared with IR group (P<0.01) and also in female IPC compared with male IPC group. β-carotene levels had no significant variations. Histological evaluation showed that IR-induced renal injuries were less in female rats. Also, protective effects of IPC were more in female rats (P<0.01).

CONCLUSIONS

Renal IPC reduced damages in both male and female rats, but tissue injuries in females were decreased much more along with the increase of endogenous vitamin E.

Association of pre-transplant statin use with delayed graft function in kidney transplant recipients

Background

Administration of HMG-CoA reductase inhibitors (statins), prior to ischemia or prior to reperfusion has been shown to decrease ischemia-reperfusion renal injury in animal studies. It is unknown whether this protective effect is applicable to renal transplantation in humans. The aim of this study was to determine the relationship between prior statin use in renal transplant recipients and the subsequent risk of delayed graft function.

Methods

All patients who underwent deceased or living donor renal transplantation at the Princess Alexandra Hospital between 1 July 2008 and 1 August 2010 were included in this retrospective, observational cohort study. Graft function was classified as immediate graft function (IGF), dialysis-requiring (D-DGF) and non-dialysis-requiring (ND-DGF) delayed graft function. The independent predictors of graft function were evaluated by multivariable logistic regression, adjusting for donor characteristics, recipient characteristics, HLA mismatch and ischaemic times.

Results

Overall, of the 266 renal transplant recipients, 21% exhibited D-DGF, 39% had ND-DGF and 40% had IGF. Statin use prior to renal transplantation was not significantly associated with the risk of D-DGF (adjusted odds ratio [OR] 1.05, 95% CI 0.96 – 1.15, P = 0.28). This finding was not altered when D-DGF and ND-DGF were pooled together (OR 0.98; 95% CI 0.89-1.06, p = 0.56).

Conclusions

The present study did not show a significant, independent association between prior statin use in kidney transplant recipients and the occurrence of delayed graft function.

Pilot double-blind, randomized controlled trial of short-term atorvastatin for prevention of acute kidney injury after cardiac surgery

AIM

To test whether short-term perioperative administration of oral atorvastatin could reduce incidence of postoperative acute kidney injury (AKI) in cardiac surgical patients.

METHODS

We conducted a double-blind, randomized controlled trial in 100 cardiac surgical patients at increased risk of postoperative AKI. Patients were randomized to atorvastatin (40 mg once daily for 4 days starting preoperatively) or identical placebo capsule. Primary outcome was to detect a smaller absolute rise in postoperative creatinine with statin therapy. Secondary outcomes included AKI defined by the creatinine criteria of RIFLE consensus classification (RIFLE R, I or F), change in urinary neutrophil gelatinase-associated lipocalin (NGAL) concentration, requirement for renal replacement therapy, length of stay in intensive care, length of stay in hospital and hospital mortality.

RESULTS

Study groups were well matched. For each patient maximal increase in creatinine during the 5 days after surgery was assessed; median maximal increase was 28 µmol/L in the atorvastatin group and 29.5 µmol/L in the placebo group (P = 0.62). RIFLE R or greater occurred in 26% of patients with atorvastatin and 32% with placebo (P = 0.65). Postoperatively urine NGAL changes were similar (median NGAL : creatinine ratio at intensive care unit admission: atorvastatin group 1503 ng/mg, placebo group 1101 ng/mg; P = 0.22). Treatment was well tolerated and adverse events were similar between groups.

CONCLUSION

Short-term perioperative atorvastatin use was not associated with a reduced incidence of postoperative AKI or smaller increases in urinary NGAL. (ClinicalTrials.gov NCT00910221).

The Effect of Statins and Other Cardiovascular Medication on Ischemia-Reperfusion Damage in a Human DIEP Flap Model: Theoretical and Epidemiological Considerations

Background. Statins and other cardiovascular medication possess antioxidant capacity. It was examined whether chronic use of these medications protects from the development of ischemia-reperfusion (I/R) related complications after DIEP (Deep Inferior Epigastric Perforator Free Flap) surgery. This paper contains a literature study on the antioxidant working mechanisms of these drugs. Methods. Medical information of 134 DIEP patients (173 flaps) was studied from their medical files. Patient and operative characteristics were registered, as well as I/R related complications. Results. Of the group that didnot use statins, 16.3% developed complications versus 30.8% amongst patients that did use these drugs (P = 0.29). Amongst patients that chronically use other cardiovascular medication, 26.8% developed I/R related complications versus 14.4% of the patients without medication (P = 0.10). Conclusions. Chronic use of statins or other cardiovascular medication didnot decrease the occurrence of I/R related complications after DIEP surgery. Therefore, research should be aimed at evaluating short-term pre-treatment with statins.

Association between use of HMG CoA reductase inhibitors and mortality in HIV-infected patients

INTRODUCTION

HIV infection is a disease associated with chronic inflammation and immune activation. Antiretroviral therapy reduces inflammation, but not to levels in comparable HIV-negative individuals. The HMG-coenzyme A reductase inhibitors (statins) inhibit several pro-inflammatory processes and suppress immune activation, and are a logical therapy to assess for a possible salutary effect on HIV disease progression and outcomes.

METHODS

Eligible patients were patients enrolled in the Johns Hopkins HIV Clinical Cohort who achieved virologic suppression within 180 days of starting a new highly active antiretroviral therapy (HAART) regimen after January 1, 1998. Assessment was continued until death in patients who maintained a virologic suppression, with right-censoring of their follow-up time if they had an HIV RNA > 500 copies/ml. Cox proportional hazards regression was used to assess statin use as a time-varying covariate, as well as other demographic and clinical factors.

RESULTS

A total of 1538 HIV-infected patients fulfilled eligibility criteria, of whom 238 (15.5%) received a statin while taking HAART. There were 85 deaths (7 in statin users, 78 in non-users). By multivariate Cox regression, statin use was associated with a relative hazard of 0.33 (95% CI: 0.14, 0.76; P =  0.009) after adjusting for CD4, HIV-1 RNA, hemoglobin and cholesterol levels at the start of HAART, age, race, HIV risk group, prior use of ART, year of HAART start, NNRTI vs. PI-based ART, prior AIDS-defining illness, and viral hepatitis coinfection. Malignancy, non-AIDS-defining infection and liver failure were particularly prominent causes of death.

DISCUSSION

Statin use was associated with significantly lower hazard of dying in these HIV-infected patients who were being effectively treated with HAART as determined by virologic suppression. Our results suggest the need for confirmation in other observational cohorts, and if confirmed, the need for a clinical trial of statin use in HIV infection.

Atorvastatin protects renal function in the rat with acute unilateral ureteral obstruction

OBJECTIVES

To examine the effects of atorvastatin on renal hemodynamics and urinary microalbumin levels in rats with acute unilateral ureteral obstruction (UUO). Previous studies have demonstrated that treatment with statins attenuated renal structural damages in rodents with chronic UUO. However, it is not known whether statins afford protection of renal function.

METHODS

UUO was created by ligation of the left ureter in rats maintained on a regular diet or the same diet but supplemented with atorvastatin (50 mg/kg/d) for 2 weeks. Renal clearance experiments were performed after release of UUO at 1 hour, 6 hours, or 12 hours.

RESULTS

Atorvastatin treatment lowered plasma triglyceride but not cholesterol levels. Both glomerular filtration rate and effective renal plasma flow were significantly greater in atorvastatintreated rats after release of UUO at 1 hour, 6 hours, and 12 hours. Significant reduction of urinary microalbumin to creatinine ratios occurred in the atorvastatin-treated group at 12 hours but not earlier.

CONCLUSIONS

Atorvastatin treatment affords protection of renal function in acute UUO and reduces urinary microalbumin levels without lowering cholesterol levels. This pleiotropic action of atorvastatin on preservation of renal hemodynamics may be important in attenuating subsequent renal structural injury in chronic UUO.

Atorvastatin enhances humoral immune responses but does not alter renal injury in experimental crescentic glomerulonephritis

AIM

Statins are widely used for their cholesterol-lowering effects and for prevention of cardiovascular disease. Evidence indicates that these drugs also have immunomodulatory and other non-lipid lowering effects, with studies suggesting benefit in some animal models of immune (particularly T helper (Th)1)-mediated inflammatory disease and their corresponding human disease counterparts. We sought to evaluate the immunomodulatory effects and therapeutic potential of atorvastatin in experimental crescentic glomerulonephritis, a Th1-predominant animal model of glomerulonephritis.

METHODS

Autologous phase, anti-glomerular basement membrane glomerulonephritis was induced in C57BL/6 mice by intravenous injection of sheep anti-mouse glomerular basement membrane globulin. Mice were administered atorvastatin (10 or 100 mg/kg) or control (phosphate-buffered saline) daily by oral gavage. Immune responses and renal injury were assessed after 21 days.

RESULTS

Compared with control-treated mice, treatment with atorvastatin did not alter renal injury (serum creatinine, proteinuria, glomerular crescent formation) or glomerular leukocytic infiltration (CD4(+) T cells or macrophages). Atorvastatin resulted in a dose-related increase in circulating serum antibody to the disease-inducing antigen but no differences in antigen-stimulated splenocyte production of Th1/Th2 cytokines. At the higher dose, atorvastatin also led to a significant reduction in apoptosis of splenic CD4(+) T lymphocytes.

CONCLUSION

This study demonstrates that statins modulate humoral responses and alter splenic CD4(+) T cell apoptosis. However, atorvastatin does not lead to significant changes in T helper cell polarization or renal injury in experimental crescentic glomerulonephritis.

The protective effect of methylene blue in lungs, small bowel and kidney after intestinal ischemia and reperfusion

PURPOSE

To study the role of methylene blue as an inhibitor of superoxide production by xanthine oxidase.

METHODS

Thirty-two Wistar rats were divided into 2 groups of 16 animals: the control group and the experimental group. All were submitted to a laparotomy for the occlusion of the cranial mesenteric artery during 60 minutes. The reperfusion was confirmed by the pulsation of the artery after the release of the temporary ligature and color change of the intestines. In the animals of the control group, 2 ml of saline were injected in the peritoneal cavity and in the animals of the experimental group, 2 ml of methylene blue were injected in the peritoneal cavity. After reperfusion for 4 hours, the animals were then sacrificed. The lungs were excised from all 32 rats. Simultaneously, the small intestine and kidneys were ressected in 20 animals (10 from the control group and 10 from the experimental group). Samples of the organs were taken to evaluate the action of xanthine-oxidase, for histopathology studies and for characterization of the edema.

RESULTS

In the animals of the experimental group, the inflammatory lesion as well as the edema in the lung was greater than in the control group. The intestinal and renal lesions were similar in both groups, but the lung damage was superior to that observed in the intestines and kidneys. .

CONCLUSION

Despite similar action of the xanthine oxidase in the control and the experimental group, after intestinal ischemia and reperfusion, the protective effect of methylene blue was observed only in the lungs of the experimental group.

Therapeutic and predictive targets of AKI

Acute kidney injury (AKI) is a very common condition encountered in a hospital setting. AKI is an independent risk factor for in-hospital mortality. In this review, we discuss in detail about the tubular, inflammatory and vascular molecular targets of AKI which may result in therapies to improve mortality and biomarkers for earlier diagnosis of AKI.

Statin administration did not influence the progression of lung injury or associated organ failures in a cohort of patients with acute lung injury

PURPOSE

Preclinical studies suggest that HMG-CoA reductase inhibitors (statins) may attenuate organ dysfunction. We evaluated whether statins are associated with attenuation of lung injury and prevention of associated organ failure in patients with ALI/ARDS.

METHODS

From a database of patients with ALI/ARDS, we determined the presence and timing of statin administration. Main outcome measures were the development and progression of pulmonary and nonpulmonary organ failures as assessed by changes in PaO(2)/FiO(2) ratio and Sequential Organ Failure Assessment score (SOFA) between days 1 and 7 after the onset of ALI/ARDS. Secondary outcomes included ventilator free days, ICU and hospital mortality, and lengths of ICU and hospital stay.

RESULTS

From 178 patients with ALI/ARDS, 45 (25%) received statin therapy. From day 1 to day 7, the statin group showed less improvement in their PaO(2)/FiO(2) ratio (27 vs. 55, P = 0.042). Ventilator free days (median 21 vs. 16 days, P = 0.158), development or progression of organ failures (median DeltaSOFA 1 vs. 2, P = 0.275), ICU mortality (20% vs. 23%, P = 0.643), and hospital mortality (27 vs. 37%, P = 0.207) were not significantly different in the statin and non-statin groups. After adjustment for baseline characteristics and propensity for statin administration, there were no differences in ICU or hospital lengths of stay.

CONCLUSION

In this retrospective cohort study, statin use was not associated with improved outcome in patients with ALI/ARDS. We were unable to find evidence for protection against pulmonary or nonpulmonary organ dysfunction.

Comparison of the effect of lipophilic and hydrophilic statins on serum adiponectin levels in patients with mild hypertension and dyslipidemia: Kinki Adiponectin Interventional (KAI) Study

The plasma level of adiponectin, which is known as an anti-atherogenic adipocytokine, correlates inversely with the progression of atherosclerosis. An increase in the serum adiponectin level has been reported after the administration of hydrophilic pravastatin, but not after the administration of lipophilic statins thus far. We investigated whether hydrophilic pravastatin acts distinctly from simvastatin, which has the highest lipophilicity, on the favorable effect on adiponectin in dyslipidemic patients. A total of 27 dyslipidemic patients with mild hypertension were enrolled in this study. The patients were initially treated with simvastatin 10 mg/day for six months or more (mean 7.1 months), and then were switched to pravastatin 20 mg/day. The serum adiponectin, cholesterol fractionated components, and C-reactive protein (CRP) were evaluated after six-month intervals. Switching from simvastatin to pravastatin caused little change in the low-density lipoprotein cholesterol levels (103 mg/dl to 104 mg/dl, p = 0.782) and blood pressure (133/70 mmHg to 132/69 mmHg), while the serum adiponectin level significantly increased (11.9 mug/ml to 13.1 mug/ml, p = 0.009, respectively), and the serum CRP significantly decreased (0.078 mg/dl to 0.062 mg/dl, p = 0.040, respectively). Hydrophilic pravastatin increased the serum adiponectin level and decreased the CRP after switching from lipophilic simvastatin in the absence of any difference in the low-density lipoprotein cholesterol level and blood pressure. It remains possible, however, that this difference was due not only to pharmacologic lipophilicity, but also to some other specific characteristics such as the formula of statins, the subject characteristics, race, body size, high-density lipoprotein cholesterol, etc.

Acute protective effects of simvastatin in the rat model of renal ischemia-reperfusion injury: it is never too late for the pretreatment

Acute pretreatment with a single i.v. bolus injection of simvastatin (1 mg/kg) significantly protects rat kidney injured by ischemia-reperfusion (I/R) (45 min + 6 h). We aimed to determine the optimal timing of such a pretreatment. The effects of both injections of simvastatin before ischemia and reperfusion were similar regarding total histological score. However, simvastatin injected 30 min before ischemia was 30% - 75% more effective in reduction of serum creatinine levels and interstitial edema score, while its injections 5 and 30 min before reperfusion were 25% - 60% more effective in reduction of tubular necrosis score and fractional excretion of Na+. However, the observed differences do not seem to offer significant advantage in clinical settings.

Statin use is associated with early recovery of kidney injury after vascular surgery and improved long-term outcome

BACKGROUND

Acute kidney injury (AKI) after major vascular surgery is an important risk factor for adverse long-term outcomes. The pleiotropic effects of statins may reduce kidney injury caused by perioperative episodes of hypotension and/or suprarenal clamping and improve long-term outcomes.

METHODS

Of 2170 consecutive patients undergoing lower extremity bypass or abdominal aortic surgery from 1995 to 2006, cardiac risk factors and medication were noted. A total of 515/1944 (27%) patients were statin users. Creatinine clearance (CrCl) was assessed preoperatively at 1, 2 and 3 days after surgery. Outcome measures were postoperative AKI and long-term mortality. Postoperative kidney injury was defined as a >10% decrease in CrCl on Day 1 or 2, compared to the baseline. Recovery of kidney function was defined as a CrCl >90% of the baseline value at Day 3 after surgery. Multivariable Cox regression analysis, including baseline cardiovascular risk factors, baseline CrCl and propensity score for statin use, was applied to evaluate the influence of statins on early postoperative kidney injury and long-term survival.

RESULTS

AKI occurred in 664 (34%) patients [median -25% CrCl, range (-10% to -71%)]. Of these 664 patients, 313 (47%) had a complete recovery of kidney function at Day 3 after surgery. Age, hypertension, suprarenal cross-clamping and baseline CrCl predicted the development of kidney injury during the postoperative period. The incidence of kidney injury was similar among statin users and non-users (29% versus 25%, OR 1.15, 95% CI 0.9-1.5). However, if kidney function deteriorated, statin use was associated with increased odds of complete kidney function recovery (OR 2.0, 95% CI 1.0-3.8). During a mean follow-up of 6.24 years, half of the patients died (55%). Importantly, statin use was also associated with an improved long-term survival, irrespective of kidney function change (HR 0.60, 95% CI 0.48-0.75).

CONCLUSION

Statin use is associated with improved recovery from AKI after major surgery and has a beneficial effect on long-term survival.

Perioperative statin therapy and renal outcomes after major vascular surgery: a propensity-based analysis

OBJECTIVE

To evaluate how the presence and timing of statin therapy affect perioperative renal outcomes after major vascular surgery.

DESIGN

Retrospective cohort study.

SETTING

Surgical intensive care unit at a single academic medical center.

PARTICIPANTS

Patients undergoing major vascular surgery between July 2004 and October 2005.

MEASUREMENTS AND MAIN RESULTS

The presence and timing of perioperative statin administration and the propensity for receiving such therapy were noted. Renal outcomes, lengths of stay, and mortality were reviewed. One hundred fifty-one procedures were performed. Eighty-nine patients (59%) received statin therapy. There was no evidence for renal protection with perioperative statin therapy (Delta creatinine 0.2 mg/dL v 0.2 mg/dL, p = 0.41; acute renal injury/acute renal failure 8% v 6%, p = 1.00; renal replacement therapy 3% v 3%, p = 1.00; all statin v no statin, respectively). With the possible exception of early reinstitution of statin therapy in chronic statin users, subgroup analyses failed to confirm an association between statin timing and prevention of postoperative renal dysfunction.

CONCLUSIONS

In the present investigation, neither the presence nor timing of perioperative statin therapy was associated with improved renal outcomes in patients undergoing a range of major vascular procedures. A possible exception is early postoperative reinitiation of statin therapy in chronic statin users. The discrepant results of available literature preclude a definitive statement on the use of statin therapy as a means of preventing postoperative renal dysfunction. An adequately powered prospective trial is needed before advocating the routine use of statin therapy for perioperative renal protection.

Apolipoprotein A-I attenuates renal ischemia/reperfusion injury in rats

Apolipoprotein A-I (ApoA-I), the major protein component of serum high-density lipoprotein (HDL), exhibits its anti-inflammatory activity in inflammatory responses. As renal inflammation plays an important role in ischemia/reperfusion (I/R) injury of the kidney, the aim of this study was to investigate the beneficial effect of ApoA-I on renal I/R injury in rats and the underlined mechanism. Using rats subjected to renal I/R by occlusion of bilateral renal pedicles, we found that administration of ApoA-I significantly reduced serum creatinine levels, serum TNF-alpha and IL-1beta levels as well as tissue myeloperoxidase (MPO) activity, compared with I/R controls. Moreover, ApoA-I treatment suppresses the expression of intercellular adhesion molecules-1 (ICAM-1) and P-selectin on endothelium, thus diminishing neutrophil adherence and the subsequent tissue injury. These results showed that ApoA-I reduced I/R-induced inflammatory responses, decreased renal microscopic damage and improved renal function. It seems likely that ApoA-I protects kidney from I/R injury by inhibiting inflammatory cytokines release and neutrophil infiltration and activation.

Pravastatin improves renal ischemia-reperfusion injury by inhibiting the mevalonate pathway

Statins are known to lessen the severity of renal ischemia-reperfusion injury. The present study was undertaken to define the mechanism of renoprotective actions of statins using a mouse kidney injury model. Treatment of mice with pravastatin, a widely used statin, improved renal function after renal ischemia-reperfusion without lowering the plasma cholesterol level. Administration of pravastatin with mevalonate, a product of HMG-CoA reductase, eliminated renal protection suggesting an effect of pravastatin on mevalonate or its metabolism. In hypercholestrolemic apolipoprotein E knockout mice with reduced HMG-CoA reductase activity; the degree of injury was less severe than in control mice, however, there was no protective action of pravastatin on renal injury in the knockout mice. Treatment with a farnesyltransferase inhibitor (L-744832) mimicked pravastatin's protective effect but co-administration with the statin provided no additional protection. Both pravastatin and L-744832 inhibited the injury-induced increase in plasma IL-6 concentration to a similar extent. Our results suggest the protective effect of pravastatin on renal ischemia-reperfusion injury is mediated by inhibition of the mevalonate-isoprenoid pathway independent of its lipid lowering action.

Atorvastatin Donor Pretreatment Prevents Ischemia/Reperfusion Injury in Renal Transplantation in Rats: Possible Role for Aldose-Reductase Inhibition

BACKGROUND

The aim of the present study was to evaluate the effect of donor pretreatment with atorvastatin on ischemia/reperfusion (I/R) injury in renal transplantation in rats.

METHODS

Donor rats were pretreated orally with atorvastatin or vehicle 2 days prior to explantation. Kidneys were stored for 24 hr at 4 degrees C in University of Wisconsin solution and transplanted into isogeneic or allogeneic recipients.

RESULTS

Donor treatment with atorvastatin improved initial graft function, reduced renal inflammation, and the number of TUNEL-positive cells in renal tissue after prolonged cold storage and isogeneic transplantation. In the allogeneic transplantation model, donor treatment with atorvastatin reduced renal inflammation in grafts harvested after 5 days, but no improvement of long-term graft survival (24 weeks) could be observed. A genome wide gene expression profile of donor kidneys from atorvastatin treated or vehicle treated rats revealed a fivefold downregulation of aldose reductase in all atorvastatin treated animals (P<0.01). Donor treatment with an aldose-reductase inhibitor improved kidney function and reduced renal inflammation after prolonged cold storage and isogeneic transplantation.

CONCLUSION

Our data suggest that downregulation of aldose reductase in renal tissue might underlie the protective effect of donor atorvastatin treatment. Donor pretreatment with a statin or an aldose reductase inhibitor could offer a new treatment strategy to prevent transplantation associated tissue injury.

Novel pharmacological approaches to the treatment of renal ischemia-reperfusion injury: a comprehensive review

Renal ischemia-reperfusion (I-R) contributes to the development of ischemic acute renal failure (ARF). Multi-factorial processes are involved in the development and progression of renal I-R injury with the generation of reactive oxygen species, nitric oxide and peroxynitrite, and the decline of antioxidant protection playing major roles, leading to dysfunction, injury, and death of the cells of the kidney. Renal inflammation, involving cytokine/adhesion molecule cascades with recruitment, activation, and diapedesis of circulating leukocytes is also implicated. Clinically, renal I-R occurs in a variety of medical and surgical settings and is responsible for the development of acute tubular necrosis (a characteristic feature of ischemic ARF), e.g., in renal transplantation where I-R of the kidney directly influences graft and patient survival. The cellular mechanisms involved in the development of renal I-R injury have been targeted by several pharmacological interventions. However, although showing promise in experimental models of renal I-R injury and ischemic ARF, they have not proved successful in the clinical setting (e.g., atrial natriuretic peptide, low-dose dopamine). This review highlights recent pharmacological developments, which have shown particular promise against experimental renal I-R injury and ischemic ARF, including novel antioxidants and antioxidant enzyme mimetics, nitric oxide and nitric oxide synthase inhibitors, erythropoietin, peroxisome-proliferator-activated receptor agonists, inhibitors of poly(ADP-ribose) polymerase, carbon monoxide-releasing molecules, statins, and adenosine. Novel approaches such as recent research involving combination therapies and the potential of non-pharmacological strategies are also considered.

The effect of diet on simvastatin and losartan enhancement of endothelial function

Patients with hypertension take antihypertensive agents and cholesterol-lowering drugs; however, few studies describe the effects of the interaction of antihypertensive agents with statins. Therefore, the purpose of this study was to characterize the effects of losartan, simvastatin, and their combination on the progression of hypertension in the spontaneously hypertensive rats (SHRs). Also, we determined whether diet influenced the drug responses. Rats were fed three different diets - low-salt (LS), high-salt (HS), and lipid-rich (LR) - and treated with either no drug (control), losartan (LOS, 10 mg/kg/day), simvastatin (SIM, 2 mg/kg/day) or LOS combined with SIM for four weeks. After four weeks on the diets, systolic blood pressure rose in all groups and remained elevated. Treatment with LOS alone or in combination with SIM reduced BP in the rats fed the LS and HS diet, respectively. Furthermore, LOS alone increased NO in the LS and LR groups; however, LOS combined with SIM completely abolished this rise in NO in LS group. Plasma PGI2 and TXA2 levels were increased in the presence of SIM alone; however LOS combined with SIM completely blocked SIM-induced increases in PGI2 and TXA2. Kidney levels of angiotensin II were higher in the LS group and significantly increased in the HS group following treatment with LOS alone. However, kidney aldosterone levels were significantly reduced in the presence of LOS in the HS group. Total cholesterol, LDL cholesterol, and triglycerides were significantly higher in the LR group. Together, these data suggest a contribution of endogenous NO and PGs in the antihypertensive effect of LOS and SIM that may be affected by the type of diet.

Statin-Induced Increase in HDL-C and Renal Function in Coronary Heart Disease Patients

Background

Little is known about the potential of statin-induced high-density lipoprotein cholesterol (HDL-C) increase to improve renal function in coronary heart disease (CHD) patients.

Methods and Results

In thispost hocanalysis of the GREek Atorvastatin and Coronary heart disease Evaluation (GREACE) Study we investigated the effect of HDL-C increase after statin treatment on renal function. From a total of 1,600 patients, 880 were on various statins (mainly atorvastatin) and 720 were not. Other secondary prevention therapies were similar in the 2 groups. After a 3 year follow up, the lipid profile was unchanged in the statin untreated group and estimated glomerular filtration rate (eGFR) was reduced by 5.1% compared with baseline (P<0.0001). In contrast, in the statin treated group non-HDL-C was reduced by 43%, HDL-C was increased by 7% and there was a significant increase in eGFR compared with baseline by 9.8% (P<0.0001). In multiple regression analysis, the mean 7% increase in HDL-C in the treated arm during the entire study was associated with a 5.6% increase in eGFR recorded after the 6^th week of treatment. The odds ratio of eGFR increase with every 5% statin-induced rise in HDL-C was 1.78 (95% confidence interval 1.19-3.34; P=0.001).

Conclusions

Statin treatment significantly improved renal function. Statin-induced HDL-C increase significantly and independently contributed to this improvement. This finding supports the concept that improving lipid variables other than low density lipoprotein cholesterol is also beneficial to preserving renal function.

The effect of statins on preservation of kidney function in patients with coronary artery disease

PURPOSE OF REVIEW

This paper outlines evidence for the putative renal benefits of statins in people with vascular disease.

RECENT FINDINGS

The Greek Atorvastatin and Coronary Heart Disease study showed a modest improvement in kidney function over 4 years among 800 atorvastatin recipients (12%), significantly better than the decrease in kidney function (4%) in 800 placebo recipients. A secondary analysis of the Cholesterol and Recurrent Events trial suggested that pravastatin reduced the rate of kidney function loss to a greater extent in participants with dipstick-positive proteinuria (P < 0.001) and lower levels of renal function at baseline (P = 0.04). A larger post-hoc analysis from this group found that pravastatin modestly reduced the risk of acute renal failure (RR 0.60, 95% CI 0.41-0.86), but not the risk of a 25% decline in kidney function from baseline (RR 0.94, 95% CI 0.88-1.01). In the group with lower baseline kidney function (glomerular filtration rate <60 ml/min/1.73 m(2)) and proteinuria on dipstick urinalysis (n = 249), pravastatin recipients were less likely to experience a 25% or greater decrease in glomerular filtration rate (12.5% versus 19.9%) or acute renal failure (3.2% versus 8.7%).

SUMMARY

Statins may reduce the rate of kidney function loss in people with cardiovascular disease, although the clinical significance of this effect is unclear. Future studies are required before statins can be recommended solely to protect renal function.

Polyenylphosphatidylcholine pretreatment ameliorates ischemic acute renal injury in rats

AIM

Polyenylphosphatidycholine has been demonstrated to have antioxidant, cytoprotective and anti-inflammatory effects. Whether polyenylphosphatidycholine pretreatment affects ischemia/reperfusion-induced renal damage in vivo is not known and was investigated here in rats.

METHODS

Forty female Sprague-Dawley rats were divided into three groups. Group 1 (n = 10) was given saline (control, sham operated). Group 2 (n = 15) were given saline, and Group 3 (n = 15) were given polyenylphosphatidycholine (100 mg/day for 10 days prior to experiment). Groups 2 and 3 were subjected to bilateral renal ischemia (60 min) followed by reperfusion (6 h). After the reperfusion period, the rats were sacrificed and kidney tissue superoxide dismutase, glutathione, total nitrite and nitrate, malondialdehyde and myeloperoxidase levels, plasma aspartate aminotransferase, blood urea nitrogen and creatinine concentrations, and nuclear factor kappa beta expression were determined.

RESULTS

Serum levels of aspartate aminotransferase, blood urea nitrogen and creatinine were significantly decreased (P < 0.05) in the treatment group compared to those in the ischemic group. There were significant differences between treatment and ischemic groups regarding the tissue superoxide dismutase, glutathione, total nitrite and nitrate, malondialdehyde, and myeloperoxidase levels (P < 0.05). In addition, polyenylphosphatidycholine pretreatment reduced nuclear factor kappa beta expression in ischemic kidney tissue. Kidneys obtained from rats pretreated with polyenylphosphatidycholine demonstrated marked reduction of the histological features of renal injury compared to kidneys obtained from Group 2 rats, including a little vacuolization, pyknosis and necrosis.

CONCLUSIONS

Polyenylphosphatidycholine pretreatment provided significant protection against ischemia/reperfusion injury to the kidney. This treatment could be therapeutic in kidney transplantation and other conditions associated with ischemia/reperfusion injury to the kidney.

Drug Insight: immunomodulatory effects of statins—potential benefits for renal patients?

Statins inhibit 3-hydroxyl-3-methylglutaryl coenzyme A reductase, an enzyme crucial to cholesterol synthesis. Drugs of this class reduce the risk of coronary heart disease and stroke, in large part through lipid modulation. Emerging evidence indicates that statins have additional modes of action. These actions, which encompass modification of endothelial function, plaque stability, thrombus formation and inflammatory pathways, are widely referred to as 'pleiotropic effects'. These pleiotropic effects indicate that the therapeutic potential of statins might extend beyond cholesterol lowering and cardiovascular disease to other inflammatory disorders or conditions such as transplantation, multiple sclerosis, rheumatoid arthritis and chronic kidney disease. Experimental and clinical data provide evidence to support these broader applications of statins; however, more large-scale trials are needed to clarify the therapeutic benefit.

Simvastatin improves sepsis-induced mortality and acute kidney injury via renal vascular effects

Acute kidney injury (AKI) occurs in about half of patients in septic shock and the mortality of AKI with sepsis is extremely high. An effective therapeutic intervention is urgently required. Statins are 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors that also have pleiotropic actions. They have been reported to increase the survival of septic or infectious patients. But the effect of simvastatin, a widely used statin, on sepsis-induced AKI is unknown. The effects of simvastatin and tumor necrosis factor (TNF)-alpha neutralizing antibody were studied in a clinically relevant model of sepsis-induced AKI using cecal ligation and puncture (CLP) in elderly mice. Simvastatin significantly improved CLP-induced mortality and AKI. Simvastatin attenuated CLP-induced tubular damage and reversed CLP-induced reduction of intrarenal microvascular perfusion and renal tubular hypoxia at 24 h. Simvastatin also restored towards normal CLP-induced renal vascular protein leak and serum TNF-alpha. Neither delayed simvastatin therapy nor TNF-alpha neutralizing antibody improved CLP-induced AKI. Simvastatin improved sepsis-induced AKI by direct effects on the renal vasculature, reversal of tubular hypoxia, and had a systemic anti-inflammatory effect.

Effects of statins on renal function after aortic cross clamping during major vascular surgery

Ischemic reperfusion injury is an important cause of renal dysfunction after major vascular surgery and increases postoperative morbidity and mortality. The aim of the present study was to assess the effect of statins on renal function in patients at high risk for renal dysfunction, that is, those who underwent suprarenal aortic cross clamping-declamping. Seventy-seven patients (28 statin users, 57 men; mean age 69 +/- 8 years) with normal preoperative renal function requiring suprarenal aortic cross clamping-declamping during vascular surgery from 1995 to 2005 were studied. Creatinine levels were obtained before surgery and on days 1, 2, 3, 7, and 30 after surgery. An analysis-of-variance model for repeated measurements was applied to compare creatinine levels between statin users and nonusers, with adjustment for clamping time and blood loss. There were no differences in baseline clinical characteristics, preoperative creatinine levels (0.93 vs 0.96 mg/dl, p = 0.59), and glomerular filtration rate (79 vs 73 ml/min, p = 0.1). Postoperative creatinine levels during the 30 days after surgery were significantly lower in statin users than in nonusers (analysis-of-variance p <0.01, 1.17 vs 1.98 mg/dl). Postoperative hemodialysis was required (temporarily) in 7 patients (9.1%), all statin nonusers. These findings suggest an association between statin use and preserved renal function after suprarenal aortic clamping.

Ischemic acute tubular necrosis models and drug discovery: a focus on cellular inflammation

Acute renal failure (ARF) is a common cause of mortality and morbidity in hospitalized patients. Ischemia is an important cause of ARF, and ARF caused by ischemic injury is referred to as ischemic acute tubular necrosis (ATN). There is growing evidence from models that ischemic ATN is associated with intrarenal inflammation. Consequently, intrarenal inflammation is an attractive target for the development of novel drug therapies for ARF. This review outlines ischemic ATN models, the pathophysiological roles of inflammatory cells such as T and B cells in ischemic ATN models, and effective T and B cell therapeutic reagents.

Effects of statins beyond lipid lowering: Potential for clinical benefits

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Simvastatin protection against acute immune-mediated glomerulonephritis in mice

In addition to cholesterol lowering, 3-hydroxy-3-nethylglutaryl coenzyme A (HMG-CoA) reductase inhibitors limit inflammatory changes associated with atherosclerosis. There is also support for their use as inhibitors of progression in chronic renal disease, irrespective of cause. In this study, their capacity to limit acute renal inflammation was evaluated. For this purpose, mice were treated with Simvastatin either prior to, at the time of, or shortly after induction of nephrotoxic nephritis. The severity of disease was determined by evaluation of blood urea nitrogen (BUN), proteinuria, and renal histologic changes. The reversibility of benefit was evaluated by the administration of mevalonic acid along with nephrotoxic serum (NTS) and Simvastatin The severity of the acute nephritis, including proteinuria, elevated BUN, and histologic changes, was ameliorated in a dose-dependent manner, when Simvastatin was administered either prior to NTS injection or at the time of NTS injection. By contrast, Simvastatin did not alter the course of established nephritis. Coadministration of mevalonic acid, the immediate substrate following HMG-CoA reductase, abolished Simvastatin's renoprotective effect, indicating that the benefit is, at least in part, due to interference with HMG-CoA reductase and biosynthetic substrates downstream from the enzyme. These findings provide the rationale for the evaluation of the efficacy of HMG-CoA reductase inhibitors in patients with recurrent forms of renal inflammation, to limit the severity of acute exacerbations of disease, prevent renal scarring and slow the rate of progression.

Enhanced acetylcholine-induced dilation in afferent arterioles in simvastatin-fed rats

OBJECTIVE

3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors have been shown to increase renal blood flow and glomerular filtration rate independent of their lipid lowering effects. The purpose of this study was to determine the effect of simvastatin on acetylcholine-induced vasodilation in the renal microcirculation. The hypothesis of the study was that simvastatin would increase acetylcholine-induced vasodilation in the renal microcirculation.

METHODS

The hydronephrotic kidney preparation was used. On the day of the experiment the kidney was prepared for videomicroscopy and dose-response curves were done with acetylcholine and sodium nitroprusside (10(-10) M to 10(-5) M) in simvastatin-fed rats ??(n=8) and control rats (n=13). The vasodilator responses of afferent and efferent arterioles were directly quantitated using videomicroscopy. L-NAME; (N(omega)-nitro-L-arginine methyl ester) was also given in a group of simvastatin-fed rats (10(-5) M) to determine if it would block the acetylcholine (Ach)-induced vasodilation.

RESULTS

Simvastatin enhanced Ach-induced vasodilation in the afferent arteriole compared to control rat responses to Ach. At 10(-7) M, ACH caused a 31.6+/-7.2% increase from baseline diameter in the afferent arteriole in the simvastatin-fed rats compared to a 23+/-8.1% vasodilation in the control rats (p<0.05). There were no differences in the response to ACH in the efferent arteriole between the two groups. L-NAME completely abolished the ACH response in the simvastatin-fed rats.

CONCLUSIONS

The increase in renal blood flow and glomerular filtration rate observed with simvastatin may be due to its preglomerular vasodilator effects. This may be due to an increase in nitric oxide production.