Pravastatin treatment attenuates interstitial inflammation and fibrosis in a rat model of chronic cyclosporine-induced nephropathy

Anti-fibrotic effects of statin drugs: a review of evidence and mechanisms

Fibrosis is a pathological repair process common among organs, that responds to damage by replacement of tissue with non-functional connective tissue. Despite the widespread prevalence of tissue fibrosis, manifesting in numerous disease states across myriad organs, therapeutic modalities to prevent or alleviate fibrosis are severely lacking in quantity and efficacy. Alongside development of new drugs, repurposing of existing drugs may be a complementary strategy to elect anti-fibrotic compounds for pharmacologic treatment of tissue fibrosis. Drug repurposing can provide key advantages to de novo drug discovery, harnessing the benefits of previously elucidated mechanisms of action and already existing pharmacokinetic profiles. One class of drugs a wealth of clinical data and extensively studied safety profiles is the statins, a class of antilipidemic drugs widely prescribed for hypercholesterolemia. In addition to these widely utilized lipid-lowering effects, increasing data from cellular, pre-clinical mammalian, and clinical human studies have also demonstrated that statins are able to alleviate tissue fibrosis originating from a variety of pathological insults via lesser-studied, pleiotropic effects of these drugs. Here we review literature demonstrating evidence for direct effects of statins antagonistic to fibrosis, as well as much of the available mechanistic data underlying these effects. A more complete understanding of the anti-fibrotic effects of statins may enable a clearer picture of their anti-fibrotic potential for various clinical indications. Additionally, more lucid comprehension of the mechanisms by which statins exert anti-fibrotic effects may aid in development of novel therapeutic agents that target similar pathways but with greater specificity or efficacy.

Inflammatory bowel disease-associated intestinal fibrosis

Fibrosis is characterized by a proliferation of fibroblasts and excessive extracellular matrix following chronic inflammation, and this replacement of organ tissue with fibrotic tissue causes a loss of function. Inflammatory bowel disease (IBD) is a chronic inflammation of the gastrointestinal tract, and intestinal fibrosis is common in IBD patients, resulting in several complications that require surgery, such as a stricture or penetration. This review describes the pathogenesis and various factors involved in intestinal fibrosis in IBD, including cytokines, growth factors, epithelial-mesenchymal and endothelial-mesenchymal transitions, and gut microbiota. Furthermore, histopathologic findings and scoring systems used for stenosis in IBD are discussed, and differences in the fibrosis patterns of ulcerative colitis and Crohn's disease are compared. Biomarkers and therapeutic agents targeting intestinal fibrosis are briefly mentioned at the end.

The association between visceral adiposity with systemic inflammation, oxidative stress, and risk of post-surgical adhesion

Abdominal and pelvic adhesions are common post-operative complications. Despite new medical technologies, these adhesions are appearing to be unavoidable and little is known about their causation; for example, why certain patients/or tissues are more prone to adhesions. There have been no clinical studies about increasing the risk adhesions in obese patients, but there is some evidence about the molecular mechanisms involving visceral fat (VF) that may lead to profibrotic conditions. VF is an endocrine/inflammatory organ which produces many biologically active molecules such as adipokines and inflammatory cytokines. Inflammatory conditions, oxidative stress, and the expression some fibrotic molecules in the VF may induce pathological conditions in the abdominal cavity that predispose to the formation of fibrotic bands.

Effect of dual inhibition of DPP4 and SGLT2 on tacrolimus-induced diabetes mellitus and nephrotoxicity in a rat model

Sodium/glucose co-transporter-2 inhibitor (SGLT2i) or dipeptidyl peptidase IV inhibitor (DPP4i) is a newer anti-diabetic drug in type II diabetes mellitus (DM), but their use in tacrolimus (TAC)-induced DM is still undetermined. We performed this study to evaluate the effect of these two drugs in TAC-induced DM and nephrotoxicity in ex vivo and in vivo. In the experimental Sprague Dawley rat model of TAC-induced DM and nephrotoxicity, dual inhibition of DPP4 and SGLT2 significantly decreased blood glucose level, HbA1C and increased plasma insulin levels and pancreatic islet size compared with each drug. In the kidney, dual inhibition improved renal function decreased interstitial fibrosis and profibrotic cytokines compared with DPP4i and SGLT2i alone. Increased oxidative stress by TAC was remarkably decreased with DPP4i or SGLT2i in serum, pancreatic and renal tissues and this decrease was much more significant in the combination group. In in vitro study, TAC decreased the cell viability of human kidney-2(HK-2) cells and insulin-secreting beta-cell-derived line(INS-1) cells. SGLT2i protected TAC-induced cell death in HK-2 cells, but not in INS-1 cells. The addition of DPP4i to SGLT2i compensated for a lack of protective effect of SGLT2i on INS-1 cells. This finding provides the rationale for the combined treatment of SGLG2i and DPP4i in TAC-induced DM and nephrotoxicity.

Revisiting fibrosis in inflammatory bowel disease: the gut thickens

Intestinal fibrosis, which is usually the consequence of chronic inflammation, is a common complication of inflammatory bowel disease (IBD), including Crohn's disease and ulcerative colitis. In the past few years, substantial advances have been made in the areas of pathogenesis, diagnosis and management of intestinal fibrosis. Of particular interest have been inflammation-independent mechanisms behind the gut fibrotic process, genetic and environmental risk factors (such as the role of the microbiota), and the generation of new in vitro and in vivo systems to study fibrogenesis in the gut. A huge amount of work has also been done in the area of biomarkers to predict or detect intestinal fibrosis, including novel cross-sectional imaging techniques. In parallel, researchers are embarking on developing and validating clinical trial end points and protocols to test novel antifibrotic agents, although no antifibrotic therapies are currently available. This Review presents the state of the art on the most recently identified pathogenic mechanisms of this serious IBD-related complication, focusing on possible targets of antifibrotic therapies, management strategies, and factors that might predict fibrosis progression or response to treatment.

Development of Anti-fibrotic Therapy in Stricturing Crohn's Disease: Lessons from Randomized Trials in Other Fibrotic Diseases

Intestinal fibrosis is considered an inevitable complication of Crohn's disease (CD) that results in symptoms of obstruction and stricture formation. Endoscopic or surgical treatment is required to treat the majority of patients. Progress in the management of stricturing CD is hampered by the lack of effective anti-fibrotic therapy; however, this situation is likely to change because of recent advances in other fibrotic diseases of the lung, liver and skin. In this review, we summarized data from randomized controlled trials (RCT) of anti-fibrotic therapies in these conditions. Multiple compounds have been tested for the anti-fibrotic effects in other organs. According to their mechanisms, they were categorized into growth factor modulators, inflammation modulators, 5-hydroxy-3-methylgultaryl-coenzyme A (HMG-CoA) reductase inhibitors, intracellular enzymes and kinases, renin-angiotensin system (RAS) modulators and others. From our review of the results from the clinical trials and discussion of their implications in the gastrointestinal tract, we have identified several molecular candidates that could serve as potential therapies for intestinal fibrosis in CD.

Water-soluble coenzyme Q10 provides better protection than lipid-soluble coenzyme Q10 in a rat model of chronic tacrolimus nephropathy

BACKGROUND/AIMS

Coenzyme Q10 (CoQ10), is a promising antioxidant; however, low bioavailability owing to lipid-solubility is a limiting factor. We developed water-soluble CoQ10 (CoQ10-W) and compared its effects with conventional lipid-soluble CoQ10 (CoQ10-L) in an experimental model of chronic tacrolimus (Tac) nephropathy.

METHODS

CoQ10-W was developed from a glycyrrhizic-carnitine mixed layer CoQ10 micelle based on acyltransferases. Chronic nephropathy was induced in rats with 28-day Tac treatment; they were concomitantly treated with CoQ10-L or CoQ10-W. CoQ10 level in plasma and kidney were measured using liquid chromatography-mass spectrometry. CoQ10-W and CoQ10-L effects on Tac-induced nephropathy were assessed in terms of renal function, histopathology, oxidative stress, and apoptotic cell death. Their effects on cell viability and reactive oxygen species (ROS) production were assessed in cultured proximal tubular cells, human kidney 2 (HK-2) cells.

RESULTS

The plasma CoQ10 level was significantly higher in the CoQ10-W group than in the CoQ10-L group. Tac treatment caused renal dysfunction, typical pathologic lesions, and oxidative stress markers. Serum creatinine was restored in the Tac + CoQ10-L or CoQ10-W groups compared with that in the Tac group. CoQ10-W administration reduced oxidative stress and apoptosis markers. Mitochondrial ultrastructure assessment revealed that the addition of CoQ10-L or CoQ10-W with Tac increased mitochondrial size and number than Tac treatment alone. In vitro investigations revealed that both CoQ10-L and CoQ10-W improved cell viability and reduced ROS production in the Tac-induced HK-2 cell injury.

CONCLUSION

CoQ10-W has a better therapeutic effect in Tac-induced renal injury than conventional CoQ10-L, possibly associated with improved CoQ10 bioavailability.

Role of Klotho in Chronic Calcineurin Inhibitor Nephropathy

Calcineurin inhibitors (CNIs) are the most popular immunosuppressants in organ transplantation, but nephrotoxicity is a major concern. The common mechanism underlying chronic CNI nephropathy is oxidative stress, and the process of chronic CNI nephropathy is similar to that of aging. Current studies provide evidence that antiaging Klotho protein plays an important role in protecting against oxidative stress, and its signaling is a target for preventing oxidative stress-induced aging process. In this review, we focus on the association between Klotho and oxidative stress and the protective mechanism of action of Klotho against oxidative stress in chronic CNI nephropathy. In addition, we discuss the delivery strategy for Klotho in CNI-induced nephropathy.

Role of a RhoA/ROCK-Dependent Pathway on Renal Connexin43 Regulation in the Angiotensin II-Induced Renal Damage

In various models of chronic kidney disease, the amount and localization of Cx43 in the nephron is known to increase, but the intracellular pathways that regulate these changes have not been identified. Therefore, we proposed that: "In the model of renal damage induced by infusion of angiotensin II (AngII), a RhoA/ROCK-dependent pathway, is activated and regulates the abundance of renal Cx43". In rats, we evaluated: 1) the time-point where the renal damage induced by AngII is no longer reversible; and 2) the involvement of a RhoA/ROCK-dependent pathway and its relationship with the amount of Cx43 in this irreversible stage. Systolic blood pressure (SBP) and renal function (urinary protein/urinary creatinine: Uprot/UCrea) were evaluated as systemic and organ outcomes, respectively. In kidney tissue, we also evaluated: 1) oxidative stress (amount of thiobarbituric acid reactive species), 2) inflammation (immunoperoxidase detection of the inflammatory markers ED-1 and IL-1β), 3) fibrosis (immune detection of type III collagen; Col III) and 4) activity of RhoA/ROCK (amount of phosphorylated MYPT1; p-MYPT1). The ratio Uprot/UCrea, SBP, oxidative stress, inflammation, amount of Cx43 and p-MYPT1 remained high 2 weeks after suspending AngII treatment in rats treated for 4 weeks with AngII. These responses were not observed in rats treated with AngII for less than 4 weeks, in which all measurements returned spontaneously close to the control values after suspending AngII treatment. Rats treated with AngII for 6 weeks and co-treated for the last 4 weeks with Fasudil, an inhibitor of ROCK, showed high SBP but did not present renal damage or increased amount of renal Cx43. Therefore, renal damage induced by AngII correlates with the activation of RhoA/ROCK and the increase in Cx43 amounts and can be prevented by inhibitors of this pathway.

Shen-Kang protects against tacrolimus-induced renal injury

BACKGROUND/AIMS

Evidence suggests that Shen-Kang (SK), a traditional Chinese herbal medicine, protects against various types of renal injury. In this study, we evaluated whether SK treatment confers renoprotection in a rat model of chronic tacrolimus (TAC) nephropathy.

METHODS

Rats were treated daily with TAC (1.5mg/kg, subcutaneously) and SK (450 mg/kg, intravenously) for 4 weeks. The effects of SK on TAC-induced renal injury were assessed by measuring renal function, urine albumin excretion, histopathology, inflammatory cell infiltration, expression of profibrotic (transforming growth factor β1 [TGF-β1] and TGF-β inducible gene-h3 [βig-h3]) and proinflammatory cytokines, oxidative stress, and apoptotic cell death.

RESULTS

Administration of SK preserved glomerular integrity (fractional mesangial area and Wilms tumor 1-positive glomeruli), attenuated tubulointerstitial fibrosis, and reduced the number of ectodermal dysplasia 1-positive cells, and this was paralleled by improved urine albumin excretion and renal dysfunction. At the molecular level, SK treatment suppressed expression of TGF-β1/Smad2/3, βig-h3, and proinflammatory cytokines. Oxidative stress and apoptotic cell death were significantly decreased with SK treatment, and apoptosis-related genes were regulated toward cell survival (active caspase-3 and the B-cell lymphoma-2/Bcl2-associated X [Bcl-2/Bax] ratio).

CONCLUSION

SK protects against TAC-induced renal injury.

Cilastatin protects against tacrolimus-induced nephrotoxicity via anti-oxidative and anti-apoptotic properties

BACKGROUND

Cilastatin (CL) is an inhibitor of dehydropeptidase-I, which is safely used in clinical practice to prevent nephrotoxicity of antibiotics. Tacrolimus (TAC) is the most important immunosuppressant in renal transplantation, but it causes considerable nephrotoxicity. We evaluated the protective effects of CL against chronic TAC-induced nephropathy.

METHODS

Chronic nephropathy was induced by administering TAC (1.5 mg/kg/ day, subcutaneous injection) to rats on a low-salt diet for 4 weeks. CL (75 or 150 mg/kg/day, intraperitoneal injection) was concomitantly treated with TAC. Human proximal tubular cells were exposed to TAC (50 μg/mL) with or without CL (250 μg/mL). We investigated the effects of CL on TAC-induced injury in terms of renal function, tubulointerstitial fibrosis, and inflammation. The effects of CL on oxidative stress and apoptosis were evaluated in both in vivo and in vitro models of TAC nephrotoxicity.

RESULTS

CL treatment improved TAC-induced renal dysfunction and decreased renal interstitial fibrosis (reduced expression of e-cadherin and TGFβ-1) and interstitial inflammation (decreased infiltration of ED-1-positive and osteopontin-positive cells). Compared to TAC treatment alone, CL co-treatment reduced oxidative stress (serum 8-OHdG level and immunoreactivity of 8-OHdG and 4-HHE in renal tissue) and increased renal expression of anti-oxidant enzyme, manganese superoxide dismutase. CL treatment decreased apoptotic cell death (decreased TUNEL-positive cells and reduced expression of active caspase-3) in TAC-treated kidney. In vitro CL treatment prevented tubular cell death from TAC treatment and decreased number of annexin V-positive cells were observed in cilastatin-cotreated cells.

CONCLUSION

CL has protective effects against chronic TAC-induced nephrotoxicity owing to its anti-oxidative and anti-apoptotic properties.

Boldine Improves Kidney Damage in the Goldblatt 2K1C Model Avoiding the Increase in TGF-β

Boldine, a major aporphine alkaloid found in the Chilean boldo tree, is a potent antioxidant. Oxidative stress plays a detrimental role in the pathogenesis of kidney damage in renovascular hypertension (RVH). The activation of the renin-angiotensin system (RAS) is crucial to the development and progression of hypertensive renal damage and TGF-β is closely associated with the activation of RAS. In the present study, we assessed the effect of boldine on the progression of kidney disease using the 2K1C hypertension model and identifying mediators in the RAS, such as TGF-β, that could be modulated by this alkaloid. Toward this hypothesis, rats (n = 5/group) were treated with boldine (50 mg/kg/day, gavage) for six weeks after 2K1C surgery (pressure ≥ 180 mmHg). Kidney function was evaluated by measuring of proteinuria/creatininuria ratio (U prot/U Crea), oxidative stress (OS) by measuring thiobarbituric acid reactive substances (TBARS). The evolution of systolic blood pressure (SBP) was followed weekly. Alpha-smooth muscle actin (α-SMA) and Col III were used as markers of kidney damage; ED-1 and osteopontin (OPN) were used as markers of inflammation. We also explored the effect in RAS mediators, such as ACE-1 and TGF-β. Boldine treatment reduced the UProt/UCrea ratio, plasma TBARS, and slightly reduced SBP in 2K1C hypertensive rats, producing no effect in control animals. In 2K1C rats treated with boldine the levels of α-SMA, Col III, ED-1, and OPN were lower when compared to 2K1C rats. Boldine prevented the increase in ACE-1 and TGF-β in 2K1C rats, suggesting that boldine reduces kidney damage. These results suggest that boldine could potentially be used as a nutraceutic.

Effect of Empagliflozin on Tacrolimus-Induced Pancreas Islet Dysfunction and Renal Injury

An inhibitor of sodium glucose co-transporter type 2 (SGLT-2) is recommended in type 2 diabetes mellitus (DM) but its use is still undetermined in tacrolimus (TAC)-induced DM. We evaluated the effect of empagliflozin (Em) on TAC-induced pancreatic islet dysfunction and renal injury in an experimental model of TAC-induced DM and in vitro. TAC induced a twofold increase in SGLT-2 expression, while Em decreased SGLT-2 expression and further increased urinary glucose excretion compared to the TAC group. Em reduced hyperglycemia and increased plasma insulin level, pancreatic islet size, and glucose-stimulated insulin secretion compared to the TAC group. In kidney, Em alleviated TAC-induced renal dysfunction and decreased albumin excretion and histological injury compared with the TAC group. Increased oxidative stress and apoptotic cell death by TAC was remarkably decreased with Em in serum and pancreatic and renal tissues. In in vitro study, TAC decreased cell viability and increased reactive oxygen species (ROS) production in both insulin-secreting beta-cell derived (INS-1) and human kidney-2 (HK-2) cell lines. Addition of Em increased cell viability and decreased ROS production in HK-2 but not in INS-1 cell lines. This suggests that Em is effective in controlling TAC-induced hyperglycemia and has direct protective effect on TAC-induced renal injury.

The development and use of a drug-induced immunosuppressed rat-model to screen Phela for mechanism of immune stimulation

ETHNOPHARMACOLOGY RELEVANCY

Phela, is code name for a medicinal product made from four South African traditional medicinal plants (Clerodendrum glabrum E. Mey, Polianthes tuberosa (Linn.), Rotheca myricoides (Hochst.) Steane & Mabb. and Senna occidentalis (L.) Link). All these plants have established traditional use in a wide spectrum of diseases. Phela is under development for use as an immune booster in immunocompromised patients, which includes patients with the human immunodeficiency virus (HIV). Already several studies, both pre-clinical and clinical, have shown that Phela is a safe and effective immune booster. Despite some studies on the action of Phela, the mechanism of action by Phela is still not known. Understanding the mechanism of action will enable safer and effective use of the drug for the right indications. Unfortunately, there is no well characterized test-system for screening products for immune stimulant activity. Therefore, the objective of this study was to use Phela as the test article, to develop and validate a rat-model (test system) by which to screen medicines for immune stimulant activity.

MATERIAL AND METHODS

First, the batch of Phela used was authenticated by high performance liquid chromatography (HPLC) techniques; analytical methods for the immunosuppressant drugs, cyclosporine A (CsA), cyclophosphamide (CP) and dexamethasone (Dex) were developed and validated; and a slide-A-Lyzer dialysis was used to test for potential interactions in rat plasma of Phela with CsA, CP and Dex. Thereafter, using Sprague Dawley (SD) rats and in separate experiments, the effective dose of Phela in the study animals was determined in a dose ranging study with levamisole, a known immune stimulant as the positive control; the appropriate doses for immunosuppression by CsA, CP and Dex were determined; the time to reach 'established immunosuppression' with each drug was determined (it was also the time for intervention with Phela); and eventually, the effect of Phela on the immune system was tested separately for each drug induced immunosuppression. The immune system was monitored by observing for changes in plasma profiles of IL-2, IL-10, IgG, IgM, CD4 and CD8 cell counts at appropriate intervals, while in addition to function tests, the kidneys, liver, spleen, thymus, were weighed and examined for any pathology.

RESULTS

The chromatographic fingerprint certified this batch of Phela as similar to the authentic Phela. There was no significant interaction between Phela and CsA, CP and Dex. The effective dose of Phela was determined to be 15.4mg/kg/day. Phela led to a moderate increase in the immune parameters in the normal rats. Co-administration of Phela 15mg/kg/day orally for 21 days with CsA led to stoppage and reversal of the immunosppressive effects of CsA that were exhibited as increased IL-2, IL-10, CD4 and CD8 counts, implying that Phela stimulates the cell mediate immunity (CMI). For CP, Phela led to stoppage and reversal, though moderate, of CP-induced suppression of IL-10, IgM and IgG only, implying that Phela stimulates the humoral immunity (HI) too. Phela had no effect on Dex induced immunosuppression. Stimulation of the CMI means that Phela clinical testing programme should focus on diseases or disorders that compromise the CMI, e.g., HIV and TB. The stimulation of the HI immunity means that Phela may stimulate existing memory cells to produce antibodies.

CONCLUSION

The present study has revealed Phela's mechanism of action as mainly by stimulation of the CMI, implying that the use of Phela as immune booster in HIV patients is appropriate; and that using Phela as the test product, a rat model for screening medicinal products for immune stimulation has been successfully developed and validated, with a hope that it will lead to the testing of other related medicinal products.

Role of mesenchymal stem cells versus angiotensin converting enzyme inhibitor in kidney repair

AIM

The current study sought to clarify the role of bone marrow derived mesenchymal stem cells (BM-MSCs) and adipose tissue derived mesenchymal stem cells (AD-MSCs) in repressing nephropathy in the experimental model. Moreover, the aim of this work was extended to compare between stem cells role and angiotensin converting enzyme inhibitor in kidney repair.

METHODS

Isolation and preparation of MSCs culture, flow cytometry using CD34, CD44 and CD105 cell surface markers, biochemical analyses for determination of serum creatinine, urea, transforming growth factor β (TGF-β), cystatin C (CYS-C) and urinary N-Acetyl-ß-D-Glucosaminidase (UNAG), and histopathological investigation of kidney tissue sections were performed.

RESULTS

The results of the present study revealed that single intravenous infusion of MSCs either derived from bone marrow or adipose tissue was able to enhance renal reparative processes through significantly decreased serum creatinine, urea, TGF-β and CYS-C levels as well as UNAG level and significantly increase glomerular filtration rate. Additionally, the histopathological investigations of kidney tissues showed that MSCs have significant regenerative effects as evidenced by the decrease in focal inflammatory cells infiltration, focal interstitial nephritis and congested glomeruli as well as degenerated tubules.

CONCLUSION

The current data provided distinct evidence about the favourable impact of AD-MSCs and BM-MSCs in attenuation of cyclosporine-induced nephropathy in rats through their ability to promote functional and structural kidney repair via transdifferentiation.

The Protective Effect of Febuxostat on Chronic Tacrolimus-Induced Nephrotoxicity in Rats

BACKGROUND

The use of calcineurin inhibitors is a well-known risk factor for hyperuricemia in kidney transplant recipients. We evaluated the effect of febuxostat (Fx), a new uric acid-lowering drug, on hyperuricemia and renal injury in an experimental model of chronic tacrolimus (Tac)-induced nephropathy.

METHODS

Chronic Tac nephropathy was induced by administering Tac (1.5 mg/kg/day) to rats on a low-salt diet (0.05%) with oxonic acid (OA, 2%, 0.2 g/kg/day) for 28 days. Two doses of Fx (5 and 10 mg/kg) were concomitantly administered with Tac or vehicle (Vh). We evaluated the effect of Fx on hyperuricemia by measuring serum uric acid (SUA) levels, fractional excretion of uric acid (FEUA), and urate transporters in Tac-induced nephropathy. The effects of Fx on Tac-induced renal injury were evaluated in terms of renal function and arteriolopathy, tubulointerstitial fibrosis, inflammation, and apoptosis. We evaluated oxidative stress as a protective mechanism via xanthine oxidase (XO) activity, and as a marker of oxidative stress (via evaluation of levels of 8-hydroxy-2'-deoxyguanosine (8-OHdG) and 4-hydroxy-2-hexenal (4-HHE)).

RESULTS

The Tac group showed higher SUA levels and lower FEUA than did the Vh group, but Fx treatment significantly decreased SUA levels in a dose-dependent manner, with an increase of FEUA at a high dose (10 mg/kg). Tac treatment increased urate-anion exchanger 1 and decreased organic anion transporter type 1 expression in renal tubular cells, but Fx treatment reversed the effects on those transporters. Impaired renal function and histological injury (interstitial fibrosis, inflammation, and arteriolopathy) in the Tac group were markedly improved by Fx administration. Increases in apoptotic cell death and activation of proapoptotic caspase-3 by Tac were remarkably decreased by Fx treatment. Tac administration increased the activity of XO in kidney tissue and serum, and the levels of 8-OHdG in urine and 8-OHdG and 4-HHE of kidney tissue, but combined treatment with Fx decreased the levels of these parameters.

CONCLUSIONS

Fx is effective in controlling hyperuricemia and in preventing Tac-induced renal injury, via a reduction of oxidative stress. Therefore, a targeted therapy aimed at inhibiting uric acid by Fx may be a useful approach in the management of the progression of nephropathy in renal transplant patients treated with Tac.

Pravastatin and Clopidogrel Combined Inhibit Intimal Hyperplasia in a Rat Carotid Endarterectomy Model

Intimal hyperplasia, resulting from a complex cascade of events involving platelets, leukocytes, and smooth muscle cells, may be inhibited by the HMG-CoA reductase inhibitor pravastatin, which demonstrates inhibition of platelet activity and leukocyte adhesion and may be associated with inhibition of vascular smooth muscle cell proliferation and migration. Clopidogrel, an adenosine diphosphate (ADP) receptor inhibitor, was shown to decrease platelet activity and aggregation but not intimal hyperplasia (IH). We postulated that the combination of both pravastatin and clopidogrel would significantly decrease IH in a rat carotid endarterectomy model. Male Sprague-Dawley rats (n = 18) divided by treatment regimen underwent treatment for 2 weeks both before and after an open carotid endarterectomy. Serum collected at the time of harvest was measured for C-reactive protein (CRP), platelet activity, and total serum cholesterol; carotid arteries were removed and processed for IH determination. Control rats (n = 7) received oral vehicle daily before and following endarterectomy. Pravastatin-alone rats (n = 6) received oral pravastatin (10 mg/kg/day) before and after endarterectomy. Pravastatin plus clopidogrel rats (n = 5) received oral pravastatin (10 mg/kg/day) plus a preendarterectomy bolus of oral clopidogrel (4.3 mg/kg) before endarterectomy and resumed pravastatin (10 mg/kg/day) plus oral clopidogrel (1 mg/kg/day) postendarterectomy. Pravastatin alone and pravastatin plus clopidogrel significantly decreased CRP compared to controls (120.2 ±11.2 and 134.1 ±9.9 vs 191.1 ±9.2 µg/mL, respectively p = 0.003 and p = 0.0024). CRP levels were not different between pravastatin alone and pravastatin plus clopidogrel (p = 0.35). Platelet activity was significantly decreased by pravastatin alone and pravastatin plus clopidogrel in comparison to controls (7.3 ±2.2 and 6.6 ±2.8 vs 19.2 ±6.1 platelet reactive units (PRU), respectively p = 0.048 and p = 0.045). No significant difference was noted in platelet activity between pravastatin alone and pravastatin plus clopidogrel (p = 0.89). Pravastatin plus clopidogrel significantly reduced serum cholesterol compared to control and pravastatin alone (84.0 ±6.6 vs 110.4 ±7.4 and 117.0 ±8.8 mg/dL, respectively p = 0.03 and p = 0.01). Pravastatin alone did not decrease serum cholesterol compared to controls (p = 0.54). IH was not reduced by pravastatin alone compared to controls (p = 0.61) but was significantly decreased by pravastatin plus clopidogrel in comparison to control and pravastatin alone (3.0 ±1.1 vs 46.3 ±13.7 and 37.4 ±14.6% luminal stenosis, respectively p = 0.01 and p = 0.05). Pravastatin plus clopidogrel significantly decreased CRP, platelet activity, total serum cholesterol, and IH while pravastatin alone decreased only CRP and platelet activity. Intimal hyperplasia reduction may therefore be dependent on other contributors, possibly growth factors, cytokines, and oxidative stress. The combination of pravastatin plus clopidogrel may have synergistic or even additional inhibitory effects on IH. Pravastatin plus clopidogrel was effective in decreasing IH in a rat carotid endarterectomy model and may prove a useful therapy for IH reduction in the clinical setting.

Treatment with atorvastatin attenuates progression of insulin resistance and pancreatic fibrosis in the Otsuka Long-Evans Tokushima fatty rats

PURPOSE

The effects of statins on insulin resistance (IR) and type 2 diabetes mellitus (T2DM) are still controversial and its effects on pancreatic fibrosis are poorly defined. The purpose of this study is to examine the effects of atorvastatin on these issues using the Otsuka Long-Evans Tokushima Fatty (OLETF) rat, an animal model of IR, T2DM and pancreatic fibrosis.

METHODS

Male OLETF rats were divided into 2 groups at 6weeks of age. The first group received a standard diet until the end of experimental period at age 28weeks. The second group was given a diet containing 0.05% atorvastatin from 6weeks of age, before the onset of IR and pancreatic fibrosis. The age-matched Long-Evans Tokushima Otsuka rats without presence of IR, T2DM and pancreatic fibrosis, received a standard diet and were used as a normal control.

RESULTS

Atorvastatin slightly decreased serum fasting glucose and insulin levels, but significantly improved index of IR compared with the untreated OLETF rats. In addition, atorvastatin markedly decreased transforming growth factor-β1 mRNA expression, myeloperoxidase activity and proportion of fibrotic area, and elevated superoxide dismutase activity in the pancreas compared with the untreated OLETF rats.

CONCLUSIONS

These findings suggest that atorvastatin exerts favorable influence on progression of IR and pancreatic inflammation and fibrosis via pleiotropic effect such as anti-oxidative property.

The effects of cyclosporin A and Heteropterys tomentosa on the rat liver

Cyclosporin A (CsA) is a widely employed immunosuppressive drug that is associated with several side effects, among then hepatotoxicity. Heteropterys tomentosa is a Brazilian plant efficient in reducing damage caused by CsA on the rat testis and prostate. The aim of this study was to evaluate the effect of CsA and H. tomentosa (administered isolated or simultaneously) on the liver of Wistar rats. The animals were treated daily with water (control), CsA (15 mg/kg/day), H. tomentosa infusion or CsA+H. tomentosa, for 21 or 56 days. The treatments did not alter liver morphology or cause fibrosis. H. tomentosa administered for 21 days increased the number of hepatocyte nuclei and Kupffer cell volumetric proportion. After 56 days of treatment, H. tomentosa administration did not alter the parameters analyzed. Biochemical plasma dosages and liver stereology showed impairment caused by CsA-treatment after 21 days; these results were not observed after 56 days of treatment. The simultaneous treatment with CsA and H. tomentosa for 21 or 56 days did not alleviate nor accentuate CsA hepatic effects. The present study showed that the 21 days treatment with CsA caused more alteration to the liver than the 56 days treatment; this could be related to hepatic recovery after the long term treatment.

Inhibition of dipeptidyl peptidase IV protects tacrolimus-induced kidney injury

Accumulating evidence shows that a gut-released hormone, the glucagon-like peptide-1 (GLP-1), has not only a glucose-lowering effect but also a renoprotective effect against kidney injury. In this study, we investigated whether a dipeptidyl peptidase (DPP) IV inhibitor has a protective effect against tacrolimus-induced renal injury. Rats were treated with tacrolimus (1.5 mg/kg, subcutaneously) and the DPP IV inhibitor MK0626 (10 or 20 mg/kg, oral gavage) for 4 weeks. MK0626 treatment attenuated tacrolimus-induced renal dysfunction, tubulointerstitial fibrosis, and arteriolopathy. Moreover, these improvements were accompanied by a reduction in oxidative stress and apoptosis. MK0626 treatment increased the blood level of GLP-1 and the level of its receptor in tissue sections but did not alter the levels of other DPP IV substrates, such as neuropeptide Y and the stromal cell-derived factor-1. These data suggest that DPP IV inhibition has an important role in the renoprotection against tacrolimus-induced nephrotoxicity via antioxidative and antiapoptotic effects and preservation of the GLP-1 system.

Pravastatin improves the impaired nitric oxide-mediated neurogenic and endothelium-dependent relaxation of corpus cavernosum in aged rats

AIM

The aim of this study was to investigate the effect of pravastatin treatment on diminished corpus cavernosum (CC) function associated with aging.

METHODS

Male rats were divided into three groups as adult rats (12-14 weeks old), aged rats (72-80 weeks old) and aged rats given 10 mg/kg/d pravastatin in drinking water for six weeks. Blood pressure was measured by tail-cuff method. Total cholesterol, low-density lipoprotein-cholesterol, high-density lipoprotein-cholesterol, triglycerides and testosterone levels were estimated in blood. Changes in expression levels of endothelial nitric oxide synthase (eNOS), phosphorylated eNOS (p-eNOS) (Ser-1177), neuronal nitric oxide synthase (nNOS), NADPH oxidase subunit gp91(phox), Rho A and Rho kinase (ROCK2) in CC were assessed by immunohistochemistry. Nitric oxide (NO)-mediated endothelium-dependent and neurogenic CC relaxation were evaluated by acetylcholine (ACh, 0.1 nM-100 µM) and electrical field stimulation (EFS; 30 V, 5 ms, 2-32 Hz), respectively.

RESULTS

In aged rats, NO-mediated, both endothelium-dependent and neurogenic CC relaxation, were significantly impaired as compared to adult rats. Besides, eNOS, p-eNOS and nNOS expressions decreased significantly in CC from aged rats, while gp91(phox), RhoA and ROCK2 expressions increased significantly. The diminished relaxation in response to ACh or EFS as well as the changes in expression of these proteins in aged rats were significantly improved by pravastatin treatment.

CONCLUSION

Pravastatin improves NO-mediated CC relaxations of aged rats probably by inhibiting NADPH oxidase/Rho kinase pathways, and this effect does not seem to be associated with lipid lowering effect of this drug.

L-carnitine protects against cyclosporine-induced pancreatic and renal injury in rats

BACKGROUND

L-carnitine has protective effects against various types of injury. This study was designed to evaluate the beneficial effects of L-carnitine on pancreatic and renal injuries caused by cyclosporine (CsA).

METHODS

Rats maintained on a low sodium diet were given vehicle (olive oil, 1 mL/kg/d), CsA (15 mg/kg/d), L-carnitine (50 or 200 mg/kg/d), or a combination of CsA and L-carnitine for 4 weeks. The impact of L-carnitine on pancreatic injury was assessed by blood glucose levels, plasma insulin concentrations, and hemoglobulin A1c (HbA1c). In addition, the protective effects of L-carnitine against CsA-induced kidney injury were evaluated in terms of renal function, histopathology (inflammatory cell influx and tubulointerstitial fibrosis), oxidative stress (8-hydroxy 2'-deoxyguanosine, 8-OHdG), transforming growth factor-betal (TGF-β1), apoptosis (caspase-3), and autophagy (LC3-II).

RESULTS

CsA treatment caused diabetes, renal dysfunction, tubulointerstitial inflammation (ED-1-positive cells), and fibrosis, which were accompanied by an increase in 8-OHdG production and upregulation of TGF-β1, caspase-3, and LC3-II. Concomitant administration of L-carnitine increased plasma insulin concentrations, decreasing plasma glucose and HbA1c levels. In the kidney, L-carnitine induced dose-dependent improvement of renal function, inflammation, and fibrosis in parallel with suppression of the expression of TGF-β1 and 8-OHdG. Furthermore, the administration of L-carnitine at a high dose inhibited the expression of caspase-3 and LC3-II.

CONCLUSION

These findings suggest that L-carnitine has a protective effect against CsA-induced pancreatic and renal injuries.

Medical therapy of stricturing Crohn's disease: what the gut can learn from other organs - a systematic review

Crohn’s disease (CD) is a chronic remitting and relapsing disease. Fibrostenosing complications such as intestinal strictures, stenosis and ultimately obstruction are some of its most common long-term complications. Despite recent advances in the pathophysiological understanding of CD and a significant improvement of anti-inflammatory therapeutics, medical therapy for stricturing CD is still inadequate. No specific anti-fibrotic therapy exists and the incidence rate of strictures has essentially remained unchanged. Therefore, the current therapy of established fibrotic strictures comprises mainly endoscopic dilation as well as surgical approaches. However, these treatment options are associated with major complications as well as high recurrence rates. Thus, a specific anti-fibrotic therapy for CD is urgently needed. Importantly, there is now a growing body of evidence for prevention as well as effective medical treatment of fibrotic diseases of other organs such as the skin, lung, kidney and liver. In face of the similarity of molecular mechanisms of fibrogenesis across these organs, translation of therapeutic approaches from other fibrotic diseases to the intestine appears to be a promising treatment strategy. In particular transforming growth factor beta (TGF-β) neutralization, selective tyrosine kinase inhibitors, blockade of components of the renin-angiotensin system, IL-13 inhibitors and mammalian target of rapamycin (mTOR) inhibitors have emerged as potential drug candidates for anti-fibrotic therapy and may retard progression or even reverse established intestinal fibrosis. However, major challenges have to be overcome in the translation of novel anti-fibrotics into intestinal fibrosis therapy, such as the development of appropriate biomarkers that predict the development and accurately monitor therapeutic responses. Future clinical studies are a prerequisite to evaluate the optimal timing for anti-fibrotic treatment approaches, to elucidate the best routes of application, and to evaluate the potential of drug candidates to reach the ultimate goal: the prevention or reversal of established fibrosis and strictures in CD patients.

Lovastatin attenuates effects of cyclosporine A on tight junctions and apoptosis in cultured cortical collecting duct principal cells

We used mouse cortical collecting duct principal cells (mpkCCDc14 cell line) as a model to determine whether statins reduce the harmful effects of cyclosporine A (CsA) on the distal nephron. The data showed that treatment of cells with CsA increased transepithelial resistance and that the effect of CsA was abolished by lovastatin. Scanning ion conductance microscopy showed that CsA significantly increased the height of cellular protrusions near tight junctions. In contrast, lovastatin eliminated the protrusions and even caused a modest depression between cells. Western blot analysis and confocal microscopy showed that lovastatin also abolished CsA-induced elevation of both zonula occludens-1 and cholesterol in tight junctions. In contrast, a high concentration of CsA induced apoptosis, which was also attenuated by lovastatin, elevated intracellular ROS via activation of NADPH oxidase, and increased the expression of p47phox. Sustained treatment of cells with lovastatin also induced significant apoptosis, which was attenuated by CsA, but did not elevate intracellular ROS. These results indicate that both CsA and lovastatin are harmful to principal cells of the distal tubule, but via ROS-dependent and ROS-independent apoptotic pathways, respectively, and that they counteract probably via mobilization of cellular cholesterol levels.

Rosuvastatin attenuates inflammation, apoptosis and fibrosis in a rat model of cyclosporine-induced nephropathy

BACKGROUND/AIM

Cyclosporine (CsA)-induced kidney injury is characterized by renal dysfunction with inflammatory cell infiltrations, apoptosis and fibrosis. Pleiotropic effects of statins may exert anti-inflammatory, antiapoptotic and antifibrotic actions beyond lipid control. The aim of this study is to investigate whether rosuvastatin (RUS) has anti-inflammatory, antiapoptotic and antifibrotic effects on chronic CsA-induced nephropathy in a rat model.

METHODS

Male Sprague-Dawley rats fed a low-sodium diet were divided into three treatment groups: control (0.9% saline injection), CsA (15 mg/kg/day by subcutaneous injection), CsA + RUS (10 mg/kg/day by gastric gavage). Renal function, CsA level and lipid levels were measured at the end of 4 weeks. The expression of ED-1, transforming growth factor-β(1) (TGF-β(1)) and α-smooth muscle actin (α-SMA) for inflammation and fibrosis were examined by Western blot analysis. The expression levels of apoptosis-associated factors were examined by Western blot analysis. Apoptosis was evaluated using the terminal deoxynucleotidyl transferase-mediated biotin nick end-labeling (TUNEL) method.

RESULTS

Kidney function was decreased in CsA-treated rats compared with controls, which was attenuated by RUS. RUS did not affect the lipid level or the blood CsA level. TUNEL staining showed that RUS inhibited CsA-induced tubular apoptosis. RUS decreased CsA-induced increased expression of Bax/Bcl-2 ratio. The expressions of ED-1, α-SMA, TGF-β(1), Smad2/3, Smad4 and p-JNK were increased in CsA-treated rats, which were attenuated by RUS. Tubular atrophy and interstitial fibrosis in CsA-treated rats were attenuated by RUS supplementation.

CONCLUSION

RUS supplementation attenuates proinflammatory and apoptosis-related factors and inhibits the fibrotic pathways including the smad-dependent and smad-independent pathways in a rat model of CsA-induced nephropathy.

The Effects of Combined Treatment with an HMG-CoA Reductase Inhibitor and PPARγ Agonist on the Activation of Rat Pancreatic Stellate Cells

Background/Aims

Hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors (statins) and peroxisome proliferator-activated receptor gamma (PPARγ) ligands can modulate cellular differentiation, proliferation, and apoptosis through various pathways. It has been shown that HMG-CoA reductase inhibitors and PPARγ agonists separately inhibit pancreatic stellate cell (PaSC) activation. We studied the effects of a combination of both types of drugs on activated PaSCs via platelet-derived growth factor (PDGF), which has not previously been reported. The present study was performed to elucidate the underlying mechanisms of these effects by focusing on the impact of the signaling associated with cell-cycle progression.

Methods

Primary cultures of rat PaSCs were exposed to simvastatin and troglitazone. Proliferation was quantified using the BrdU method, and cell-cycle analysis was performed using a fluorescent activated cell sorter. The protein expression levels of smooth muscle actin (SMA), extracellular signal-regulated kinase (ERK), and a cell cycle machinery protein (p27Kip1) were investigated using Western blot analysis.

Results

Simvastatin reversed the effects of PDGF on cell proliferation in a dose-dependent manner. The combination of a low concentration of simvastatin (1 mM) and troglitazone (10 mM) synergistically reversed the effects of PDGF on cell proliferation but had no effect on cell viability. The expression of a-SMA was markedly attenuated by combining the two drugs, which blocked the cell cycle beyond the G0/G1 phase by reducing the levels of phosphorylated ERK and reversed the expression of p27Kip1 interrupted by PDGF.

Conclusions

Simvastatin and troglitazone synergistically inhibited cell proliferation in activated PaSCs by blocking the cell cycle beyond the G0/G1 phase. This inhibition was due to the synergistic modulation of the ERK pathway and the cell cycle machinery protein p27Kip1.

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.

Mesenchymal cell proliferation and programmed cell death: key players in fibrogenesis and new targets for therapeutic intervention

An exquisite equilibrium between cell proliferation and programmed cell death is required to maintain physiological homeostasis. In inflammatory bowel disease, and especially in Crohn's disease, enhanced proliferation along with defective apoptosis of immune cells are considered key elements of pathogenesis. Despite the relatively limited attention that has been given to research efforts devoted to intestinal fibrosis to date, there is evidence suggesting that enhanced proliferation along with defective programmed cell death of mesenchymal cells can significantly contribute to the development of excessive fibrogenesis in many different tissues. Moreover, some therapies have demonstrated potential antifibrogenic efficacy through the regulation of mesenchymal cell proliferation and programmed cell death. Further understanding of the pathways involved in the regulation of mesenchymal cell proliferation and apoptosis is, however, required.

Inhibition of the renal renin-angiotensin system and renoprotection by pitavastatin in type1 diabetes

1. The aim of the present study was to investigate whether or not pitavastatin ameliorates diabetic nephropathy and if inhibition of the rennin-angiotensin-aldosterone system (RAAS) is associated with any renoprotective effects. Pitavastatin (10mg/ kg/day) and/or spironolactone (100mg/kg/day) were given by gavage for 3weeks to uninephrectomized rats with streptozotocin-induced diabetes. 2. Pitavastatin or spironolactone significantly reduced proteinuria and collagen deposition, and normalized creatinine clearance, serum creatinine levels and blood urea nitrogen concentrations. 3. Reverse transcription polymerase chain reaction analysis showed that the renal expression of collagenI, transforming growth factor-β and monocyte chemoattractant-1 were increased in diabetic rats and reduced by the pitavastatin and/or spironolactone treatment. 4. These agents also decreased angiotensin converting enzyme expression and aldosterone concentrations in the renal homogenate, but had no effect on blood glucose, haemoglobinA(1c) , and plasma total cholesterol, Na(+) , K(+) , aldosterone and NOx levels, or on systolic blood pressure measured by the tail-cuff method. Interestingly, cotreatment with pitavastatin and spironolactone did not result in additional normalization. 5. These results suggest that pitavastatin shows renoprotective effects against diabetic nephropathy mediated in part by inhibition of the renal RAAS, including the suppression of angiotensin-converting enzyme expression and aldosterone production.

Fibrogenic and redox-related but not proinflammatory genes are upregulated in Lewis rat model of chronic silicosis

Silicosis, a fibrotic granulomatous lung disease, may occur through accidental high-dose or occupational inhalation of silica, leading to acute/accelerated and chronic silicosis, respectively. While chronic silicosis has a long asymptomatic latency, lung inflammation and apoptosis are hallmarks of acute silicosis. In animal models, histiocytic granulomas develop within days after high-dose intratracheal (IT) silica instillation. However, following chronic inhalation of occupationally relevant doses of silica, discrete granulomas resembling human silicosis arise months after the final exposure without significant lung inflammation/apoptosis. To identify molecular events associated with chronic silicosis, lung RNA samples from controls or subchronic silica-exposed rats were analyzed by Affymetrix at 28 wk after silica exposures. Results suggested a significant upregulation of 144 genes and downregulation of 7 genes. The upregulated genes included complement cascade, chemokines/chemokine receptors, G-protein signaling components, metalloproteases, and genes associated with oxidative stress. To examine the kinetics of gene expression relevant to silicosis, quantitative polymerase chain reaction (qPCR), enzyme-linked immunosorbent assay (ELISA), Luminex-bead assays, Western blotting, and/or zymography were performed on lung tissues from 4 d, 28 wk, and intermediate times after subchronic silica exposure and compared with 14-d acute silicosis samples. Results indicated that genes regulating fibrosis (secreted phosphoprotein-1, Ccl2, and Ccl7), redox enzymes (superoxide dismutase-2 and arginase-1), and the enzymatic activities of matrix metalloproteinases 2 and 9 were upregulated in acute and chronic silicosis models. However, proinflammatory cytokines were strongly upregulated only in acute silicosis. Thus, inflammatory cytokines are associated with acute but not chronic silicosis. Data suggest that genes regulating fibrosis, oxidative stress, and metalloproteases may contribute to both acute and chronic silicosis.

Rosuvastatin prevents proteinuria and renal inflammation in nitric oxide-deficient rats

OBJECTIVE

The aim of the present study was to assess the effects of rosuvastatin on renal injury and inflammation in a model of nitric oxide deficiency.

METHODS

Male Wistar rats were randomly divided into four groups (n = 10/group) and treated for 28 days with saline (CTRL); 30 mg/kg/day L-NAME (L-name); L-NAME and 20 mg/kg/day rosuvastatin (L-name+ROS-20); or L-NAME and 2 mg/kg/day rosuvastatin (L-name+ROS-2). Systolic blood pressure was measured by plethysmography in the central artery of the tail. The serum total cholesterol, triglycerides, alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, creatinine, nitric oxide, interleukin-6, and tumor necrosis factor alpha levels were analyzed. Urine samples were taken to measure the albumin: urinary creatinine ratio. Kidneys were sectioned and stained with hematoxylin/eosin and Masson's trichrome. Immunohistochemical analysis of the renal tissue was performed to detect macrophage infiltration of the glomeruli.

RESULTS

The systolic blood pressure was elevated in the L-name but not the L-name+rosuvastatin-20 and L-name+rosuvastatin-2 groups. The L-name group had a significantly reduced nitric oxide level and an increased interleukin-6 and tumor necrosis factor alpha level, albumin: urinary creatinine ratio and number of macrophages in the renal glomeruli. Rosuvastatin increased the nitric oxide level in the L-name+rosuvastatin-2 group and reduced the interleukin-6 and tumor necrosis factor alpha levels, glomerular macrophage number and albumin:urinary creatinine ratio in the L-name+rosuvastatin-20 and L-name+rosuvastatin-2 groups.

CONCLUSION

Rosuvastatin treatment reduced glomerular damage due to improvement in the inflammatory pattern independent of the systolic blood pressure and serum lipid level. These effects may lead to improvements in the treatment of kidney disease.

Cardiovascular pathology in Hutchinson-Gilford progeria: correlation with the vascular pathology of aging

OBJECTIVE

Children with Hutchinson-Gilford progeria syndrome (HGPS) exhibit dramatically accelerated cardiovascular disease (CVD), causing death from myocardial infarction or stroke between the ages of 7 and 20 years. We undertook the first histological comparative evaluation between genetically confirmed HGPS and the CVD of aging.

METHODS AND RESULTS

We present structural and immunohistological analysis of cardiovascular tissues from 2 children with HGPS who died of myocardial infarction. Both had features classically associated with the atherosclerosis of aging, as well as arteriolosclerosis of small vessels. In addition, vessels exhibited prominent adventitial fibrosis, a previously undescribed feature of HGPS. Importantly, although progerin was detected at higher rates in the HGPS coronary arteries, it was also present in non-HGPS individuals. Between the ages of 1 month and 97 years, progerin staining increased an average of 3.34% per year (P<0.0001) in coronary arteries.

CONCLUSIONS

We find concordance among many aspects of cardiovascular pathology in both HGPS and geriatric patients. HGPS generates a more prominent adventitial fibrosis than typical CVD. Vascular progerin generation in young non-HGPS individuals, which significantly increases throughout life, strongly suggests that progerin has a role in cardiovascular aging of the general population.

Macrophage depletion attenuates chronic cyclosporine A nephrotoxicity

BACKGROUND

Cyclosporine A (CsA)-induced chronic nephrotoxicity is characterized by renal dysfunction and interstitial fibrosis. Early and progressive renal macrophage influx, correlating with latter interstitial fibrotic areas, has been associated with CsA treatment. This study investigated the role of macrophages, the nitric oxide (NO) pathway, and the oxidative stress on chronic CsA nephrotoxicity.

METHODS

The macrophages were depleted by clodronate liposomes. Animals were distributed into four groups: vehicle (olive oil for 21 days), CsA 7.5 mg/kg per day (21 days), CsA plus clodronate (5 mg/mL intraperitoneally on days -4, 1, 4, 11, and 18 of CsA treatment), or vehicle plus clodronate. On day 22, glomerular filtration rate, renal blood flow, renal tubulointerstitial fibrosis, CsA blood levels, serum malondialdehyde and renal tissue immunohistochemistry for macrophages, inducible NO synthase, transforming growth factor-beta, nuclear factor-kbeta, alpha-smooth muscle actin, vimentin, and nitrotyrosine were assessed.

RESULTS

CsA-induced increase in the macrophage was prevented by clodronate. Macrophage depletion attenuated the reductions in the glomerular filtration rate and renal blood flow, the development of tubulointerstitial fibrosis, malondialdehyde increase and increases in nuclear factor-kbeta, transforming growth factor-beta, vimentin, inducible NO synthase, and nitrotyrosine expression provoked by CsA. Clodronate did not affect alpha-smooth muscle actin expression and CsA blood levels.

CONCLUSIONS

Renal macrophage influx plays an important role in CsA-induced chronic nephrotoxicity. The NO pathway and oxidative stress are likely mechanisms involved in the genesis of this form of renal injury.

Pravastatin attenuates carboplatin-induced nephrotoxicity in rodents via peroxisome proliferator-activated receptor alpha-regulated heme oxygenase-1

The aim of this study was to explore the molecular mechanisms underlying the protective effect of pravastatin against carboplatin-induced nephrotoxicity in rodents. We exposed rat NRK-52E renal tubular epithelial cells to carboplatin, with or without pravastatin. Pravastatin decreased production of reactive oxygen species, increased expression of heme oxygenase-1 (HO-1), cyclooxygenase-2, and 6-keto prostaglandin F1alpha, enhanced nuclear translocation of peroxisome proliferator-activated receptor-alpha (PPARalpha), and increased HO-1 promoter and peroxisome proliferator response element (PPRE) activities. We found interaction of PPARalpha with PPRE on the HO-1 promoter in nuclear extracts from pravastatin-treated NRK-52E cells and by chromatin immunoprecipitation. We pretreated mice with pravastatin and then administered a single intraperitoneal injection of carboplatin. Effects on renal function, morphology, apoptosis, and survival were assessed. In response to carboplatin injection, mice developed acute renal failure, with elevated activated caspase-3, increased apoptotic bodies, and decreased survival. Pretreatment with pravastatin significantly ameliorated renal dysfunction and apoptosis and improved renal morphology and survival. Injection of pravastatin also induced overexpression of PPARalpha and HO-1 in wild-type mice, and HO-1 expression was significantly attenuated in PPARalpha-knockout mice. These results indicate that pravastatin up-regulates HO-1 and protects against carboplatin-induced renal dysfunction and apoptosis via a PPARalpha-dependent pathway.

Synergistic antifibrotic efficacy of statin and protein kinase C inhibitor in hepatic fibrosis

Statin has antifibrotic efficacy in human fibrosing diseases, such as pulmonary and renal fibrosis, and is therefore implicated in hepatic fibrosis. However, statin can also activate protein kinase C (PKC), which augments hepatic fibrogenesis and is thereby likely to reduce the antifibrotic efficacy of statin. This study was designed to explore the hypothesis that simultaneous treatment with statin and PKC inhibitor may synergistically enhance antifibrotic efficacy in hepatic fibrosis. Hepatic fibrosis models were established in BALB/c mice by intraperitoneal injection of carbon tetrachloride or thioacetamide for 6 wk. Pravastatin and enzastaurin (PKC inhibitor) were administered by gavage for 5 wk. Cellular apoptosis was explored using 4',6-diamidino-2-phenylindole or terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate biotin nick end-labeling (TUNEL) staining and immunoblot analysis. Hepatic fibrosis and hepatic stellate cell (HSC) activation were assessed by morphometric analysis of histological findings and immunohistochemistry for alpha-smooth muscle actin. In vitro, the addition of PKC inhibitor significantly increased statin-induced LX-2 cell apoptosis by enhancing the activation of mitochondrial apoptotic signals. TUNEL-positive HSCs were significantly increased in mice treated with statin + PKC inhibitor compared with those in control or single compound-treated mice. The percentage of area occupied by activated HSCs and the extent of collagen deposition were significantly decreased in mice treated with statin + PKC inhibitor compared with those in control or statin-treated mice. In conclusion, simultaneous treatment with statin and PKC inhibitor synergistically enhanced the antifibrotic efficacy in both in vitro and in vivo models of hepatic fibrosis and may therefore have therapeutic implication for reducing hepatic fibrosis.

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.

The pathogenesis and treatment of chronic allograft nephropathy

Despite improvements in immunosuppressive therapy, long-term allograft survival after kidney transplantation remains as low as 50%. Chronic allograft nephropathy (CAN) is a major cause of late graft loss in renal transplant recipients. The histopathologic signs of CAN-interstitial fibrosis, tubular atrophy, glomerulopathy and vasculopathy-are nonspecific; therefore, the 2007 Banff classification dispensed with the term CAN in favor of 'interstitial fibrosis and tubular atrophy without evidence of any specific etiology'. In this Review, however, the term CAN is used to describe a clinical syndrome that is characterized by progressive decline in renal function from 3 months after transplantation, accompanied by the development of proteinuria and hypertension. The pathogenesis of CAN is complex and incompletely understood, and involves several immunological and non-immunological factors. We discuss the contributory roles of acute rejection, donor age, anti-human-leukocyte-antigen antibodies, calcineurin inhibitor nephrotoxic effects, viral infection, hypertension and hyperlipidemia. The prevention and treatment of CAN needs multidisciplinary strategies. Early detection by means of protocol biopsy and calculation of glomerular filtration rate is the first step, followed by management of modifiable risk factors.

Regulation of different inflammatory diseases by impacting the mevalonate pathway

The 3-hydroxy-3-methyl-glutaryl-coenzyme A reductase inhibitors (statins) interfere with the mevalonate pathway. While initially developed for their lipid-lowering properties, statins have been extensively investigated with respect to their impact on autoantigen and alloantigen driven immune responses. Mechanistically it was shown that statins modify immune responses on several levels, including effects on dendritic cells, endothelial cells, macrophages, B cells and T cells. Several lines of evidence suggest that statins act in a disease-specific manner and are not effective in each immune disorder. This review discusses possible modes of action of statins in modulating immunity towards autoantigens and alloantigens.

Calcineurin inhibitor nephrotoxicity

The use of the calcineurin inhibitors cyclosporine and tacrolimus led to major advances in the field of transplantation, with excellent short-term outcome. However, the chronic nephrotoxicity of these drugs is the Achilles' heel of current immunosuppressive regimens. In this review, the authors summarize the clinical features and histologic appearance of both acute and chronic calcineurin inhibitor nephrotoxicity in renal and nonrenal transplantation, together with the pitfalls in its diagnosis. The authors also review the available literature on the physiologic and molecular mechanisms underlying acute and chronic calcineurin inhibitor nephrotoxicity, and demonstrate that its development is related to both reversible alterations and irreversible damage to all compartments of the kidneys, including glomeruli, arterioles, and tubulo-interstitium. The main question--whether nephrotoxicity is secondary to the actions of cyclosporine and tacrolimus on the calcineurin-NFAT pathway--remains largely unanswered. The authors critically review the current evidence relating systemic blood levels of cyclosporine and tacrolimus to calcineurin inhibitor nephrotoxicity, and summarize the data suggesting that local exposure to cyclosporine or tacrolimus could be more important than systemic exposure. Finally, other local susceptibility factors for calcineurin inhibitor nephrotoxicity are reviewed, including variability in P-glycoprotein and CYP3A4/5 expression or activity, older kidney age, salt depletion, the use of nonsteroidal anti-inflammatory drugs, and genetic polymorphisms in genes like TGF-beta and ACE. Better insight into the mechanisms underlying calcineurin inhibitor nephrotoxicity might pave the way toward more targeted therapy or prevention of calcineurin inhibitor nephrotoxicity.

Established and newly proposed mechanisms of chronic cyclosporine nephropathy

Cyclosporine (CsA) has improved patient and graft survival rates following solid-organ transplantation and has shown significant clinical benefits in the management of autoimmune diseases. However, the clinical use of CsA is often limited by acute or chronic nephropathy, which remains a major problem. Acute nephropathy depends on the dosage of CsA and appears to be caused by a reduction in renal blood flow related to afferent arteriolar vasoconstriction. However, the mechanisms underlying chronic CsA nephropathy are not completely understood. Activation of the intrarenal renin-angiotensin system (RAS), increased release of endothelin-1, dysregulation of nitric oxide (NO) and NO synthase, up-regulation of transforming growth factor-beta1 (TGF-beta1), inappropriate apoptosis, stimulation of inflammatory mediators, enhanced innate immunity, endoplasmic reticulum stress, and autophagy have all been implicated in the pathogenesis of chronic CsA nephropathy. Reducing the CsA dosage or using other renoprotective drugs (angiotensin II receptor antagonist, mycophenolate mofetil, and statins, etc.) may ameliorate chronic CsA-induced renal injury. This review discusses old and new concepts in CsA nephropathy and preventive strategies for this clinical dilemma.

Strategies for blocking the fibrogenic actions of connective tissue growth factor (CCN2): From pharmacological inhibition in vitro to targeted siRNA therapy in vivo

Connective tissue growth factor (CCN2) is a major pro-fibrotic factor that frequently acts downstream of transforming growth factor beta (TGF-beta)-mediated fibrogenic pathways. Much of our knowledge of CCN2 in fibrosis has come from studies in which its production or activity have been experimentally attenuated. These studies, performed both in vitro and in animal models, have demonstrated the utility of pharmacological inhibitors (e.g. tumor necrosis factor alpha (TNF-alpha), prostaglandins, peroxisome proliferator-activated receptor-gamma (PPAR-gamma) agonists, statins, kinase inhibitors), neutralizing antibodies, antisense oligonucleotides, or small interfering RNA (siRNA) to probe the role of CCN2 in fibrogenic pathways. These investigations have allowed the mechanisms regulating CCN2 production to be more clearly defined, have shown that CCN2 is a rational anti-fibrotic target, and have established a framework for developing effective modalities of therapeutic intervention in vivo.

Fluvastatin prevents podocyte injury in a murine model of HIV-associated nephropathy

BACKGROUND

Recent studies have reported that statins have renoprotective effects, independent from lowering plasma cholesterol. In this study, we examined whether statins were beneficial in a murine model of HIV-associated nephropathy (HIVAN).

METHODS

We used conditional transgenic mice that express one of the HIV-1 accessory genes, vpr, selectively in podocytes using podocin promoter and the Tet-on system. These mice develop aggressive collapsing focal segmental glomerular sclerosis with massive proteinuria and deterioration of renal function within 4 weeks following heminephrectomy and doxycycline administration. Fluvastatin was administrated simultaneously with doxycycline, and the effect was compared with untreated controls after 4 weeks.

RESULTS

Fluvastatin at 10 mg/kg/day significantly decreased urinary albumin excretion (87 versus 11 mg/day, P < 0.01) and glomerular sclerosis (2.4 versus 1.0, P < 0.01, assessed by semi-quantitative scoring: 0-4). Fluvastatin also decreased serum creatinine and total cholesterol, but these differences were not statistically significant (0.36 versus 0.32 mg/dl, P = 0.35; 492 versus 378 mg/dl, P = 0.11, respectively). Phenotypic changes in podocytes, as indicated by the downregulation of nephrin, Wilms' tumour 1 and synaptopodin, along with upregulation of proliferating cell nuclear antigen, were attenuated by fluvastatin, suggesting its protective effects against podocyte injuries. In cultured podocytes, angiotensin II treatment decreased nephrin expression to 13% of basal levels, which was reversed to 58% by adding fluvastatin.

CONCLUSIONS

In conclusion, fluvastatin was effective in treating experimental HIVAN. The beneficial effect of this drug might be caused, in part, by preserving nephrin expression in podocytes against angiotensin II-mediated injury.

Experimental models for nephropathy

Nephropathy is a leading cause of morbidity and mortality and its prevalence is continuously increasing in industrialised nations. Nephropathy is characterised to varying degrees by nodular glomerulosclerosis, glomerular basement membrane thickness and mesangial expansion, leading to a decline in glomerular filtration rate, persistent elevated albuminuria, elevated arterial blood pressure and fluid retention. Hyperglycaemia, hyperlipidaemia and hypertension are considered to be the major risk factors implicated in the progression of nephropathy.Various signalling systems, such as vasoconstrictor peptides, inflammatory mediators, growth factors and adhesion molecules, are involved in the pathogenesis of nephropathy.At present, no promising therapy is available to treat patients with nephropathy due to lack of understanding of signalling culprits involved in the pathogenesis of nephropathy. Animal models are being developed to better understand the disease pathogenesis and develop drugs for nephropathy. In the present review, we have discussed various animal models for nephropathy, which may open vistas for developing new drugs to treat nephropathy.

Present and future drug treatments for chronic kidney diseases: evolving targets in renoprotection

At present, there are no specific cures for most of the acquired chronic kidney diseases, and renal transplantation is limited by organ shortage, therefore present efforts are concentrated on the prevention of progression of renal diseases. There is robust experimental and clinical evidence that progression of chronic nephropathies is multifactorial; however, intraglomerular haemodynamic changes and proteinuria play a key role in this process. With a focus on renoprotection, we first examine more established therapies--such as those that modulate the renin-angiotensin-aldosterone system--that can be used for the treatment of proteinuric renal diseases. We then discuss examples of novel drugs and biologics that might be used to target the inflammatory and profibrotic process, and glomerular injury, highlighting results from recent clinical trials.

Protective effect of COMP-angiopoietin-1 on cyclosporine-induced renal injury in mice

BACKGROUND

Peritubular capillary injury induces chronic hypoxia in the renal tubulointerstitium, and renal peritubular capillary dysfunction is an early event that contributes to tubulointerstitial fibrosis. Cyclosporine A (CsA) is a potent immunosuppressant and improves survival of renal allografts. However, the limitation of CsA use is chronic nephrotoxicity. A soluble, stable and potent angiopoietin-1 (Ang1) variant, cartilage oligomeric matrix protein (COMP)-Ang1 has been developed. We investigated whether COMP-Ang1 ameliorates CsA-induced renal injury.

METHODS

CsA-treated mice were injected with recombinant adenovirus expressing either COMP-Ang1 or LacZ. Histology, inflammatory, haemodynamic and fibrotic parameters, and signalling pathway were evaluated.

RESULTS

Histologic examination showed that COMP-Ang1 significantly decreased CsA-induced tubular damage and tubulointerstitial fibrosis. CsA-induced increases in macrophage infiltration and expression of MCP-1 and ICAM-1 after CsA treatment were significantly reduced by COMP-Ang1. Treatment with COMP-Ang1 also decreased the CsA-induced increases in TGF-beta1 and Smad 2/3 levels while increasing Smad 7 levels. Laser-Doppler sonographic findings and endothelial factor VIII staining revealed that COMP-Ang1 preserved the integrity of peritubular vasculature and intrarenal haemodynamics from the CsA-induced renal injury. COMP-Ang1 inhibited tubular cell apoptosis while increasing tubular cell proliferation in CsA-induced renal injury.

CONCLUSIONS

These results indicate that COMP-Ang1 exhibited a protective effect on damaged peritubular capillaries, haemodynamic alteration and inflammation in CsA-induced renal injury. Thus, COMP-Ang1 may be useful as a therapeutic and prophylactic agent for specific protection against endothelial dysfunction and inflammation.