CsA-induced Nephrotoxicity Research Articles

Provinol Prevents CsA-induced Nephrotoxicity by Reducing Reactive Oxygen Species, iNOS, and NF-kB Expression

Cyclosporine A (CsA) use is associated with several side effects, the most important of which is nephrotoxicity that includes, as we previously showed, tubular injury and interstitial fibrosis. Recently, many researchers have been interested in minimizing these effects by pharmacological interventions. To do this, we tested whether the administration of a red wine polyphenol, Provinol (PV), prevents the development of CsA-induced nephrotoxicity. Rats were treated for 21 days and divided into four groups: control; group treated with PV (40 mg/kg/day by oral administration in tap water); group treated with CsA (15 mg/kg/day by subcutaneous injection); group treated with CsA plus PV. CsA produced a significant increase of systolic blood pressure; it did not affect urinary output, but caused a significant decrease in creatinine clearance. These side effects were associated with an increase in conjugated dienes, which are lipid peroxidation products, inducible NO-synthase (iNOS), and nuclear factor (NF)-kB, which are involved in antioxidant damage. However, PV prevented these negative effects through a protective mechanism that involved reduction of both oxidative stress and increased iNOS and NF-kB expression induced by CsA. These results provide a pharmacological basis for the beneficial effects of plant-derived polyphenols against CsA-induced renal damage associated with CsA.

The Mannich Base NC1153 Promotes Long-Term Allograft Survival and Spares the Recipient from Multiple Toxicities

JAK3 is a cytoplasmic tyrosine kinase with limited tissue expression but is readily found in activated T cells. Patients lacking JAK3 are immune compromised, suggesting that JAK3 represents a therapeutic target for immunosuppression. Herein, we show that a Mannich base, NC1153, blocked IL-2-induced activation of JAK3 and its downstream substrates STAT5a/b more effectively than activation of the closely related prolactin-induced JAK2 or TNF-alpha-driven NF-kappaB. In addition, NC1153 failed to inhibit several other enzymes, including growth factor receptor tyrosine kinases, Src family members, and serine/threonine protein kinases. Although NC1153 inhibited proliferation of normal human T cells challenged with IL-2, IL-4, or IL-7, it did not block T cells void of JAK3. In vivo, a 14-day oral therapy with NC1153 significantly extended survival of MHC/non-MHC mismatched rat kidney allografts, whereas a 90-day therapy induced transplantation tolerance (>200 days). Although NC1153 acted synergistically with cyclosporin A (CsA) to prolong allograft survival, it was not nephrotoxic, myelotoxic, or lipotoxic and did not increase CsA-induced nephrotoxicity. In contrast to CsA, NC1153 was not metabolized by cytochrome P450 3A4. Thus, NC1153 prolongs allograft survival without several toxic effects associated with current immunosuppressive drugs.

HEGPOL: Randomized, placebo controlled, multicenter, double-blind clinical trial to investigate hepatoprotective effects of glycine in the postoperative phase of liver transplantation [ISRCTN69350312

BackgroundKupffer cell-dependent ischemia / reperfusion (I/R) injury after liver transplantation is still of high clinical relevance, as it is strongly associated with primary dysfunction and primary nonfunction of the graft. Glycine, a non-toxic, non-essential amino acid has been conclusively shown in various experiments to prevent both activation of Kupffer cells and reperfusion injury. Based on both experimental and preliminary clinical data this study protocol was designed to further evaluate the early effect of glycine after liver transplantation.Methods / designA prospective double-blinded randomized placebo-controlled multicenter study with two parallel groups in a total of 130 liver transplant recipients was designed to assess the effect of multiple intravenous doses of glycine after transplantation. Primary endpoints in hierarchical order are: peak levels of both aspartat-amino-transaminase (AST) and alanine-amino-transaminase (ALT) as surrogates for the progression of liver related injury, as well as both graft and patient survival up to 2 years after transplantation. Furthermore, the effect of glycine on cyclosporine A-induced nephrotoxicity is evaluated.DiscussionThe ongoing clinical trial represents an advanced element of the research chain, along which a scientific hypothesis has to go by, in order to reach the highest level of evidence; a randomized, prospective, controlled double-blinded clinical trial. If the data of this ongoing research project confirm prior findings, glycine would improve the general outcome after liver transplantation.

Effects of STZ-induced diabetes and its treatment with vanadyl sulphate on cyclosporine A-induced nephrotoxicity in rats

The aim of this study was to analyze the effect of streptozotocin (STZ)-induced diabetic state and the insulin-like acting, vanadyl sulphate (VS) on cyclosporine A (CyA) related nephrotoxicity in rats. Male Wistar rats were divided into six groups, of 12 animals each: The control, diabetic rats and diabetic rats whose drinking VS in the drinking water in a concentration of 1 mg/ml. Another three similarly treated groups were injected intra-peritoneally (ip) with CyA in a dose of 25 mg/kg/day for ten doses, 10 days after diabetic induction by using a single dose of STZ of 65 mg/kg. Rats were sacrificed 48 h after the last CyA dose and serum as well as kidneys were isolated and analyzed. Treatment with CyA to control normoglycemic rats resulted in significant increases in kidney weight, serum creatinine, urea nitrogen, cholesterol and triglycerides (TG) levels. Also, the kidney tissue of CyA-treated control animals showed significant increases in total nitrate/nitrite (NO(x)) concentration and malondialdehyde (MDA) production level as well as depletion of glutathione (GSH) content and glutathione peroxidase (GSH-P(x)) activity level. Histopathologic evaluation of CyA-treated control rats revealed tubular atrophy, hyaline casts and focal tubular necrosis. However, treatment of diabetic rats with CyA showed significant reduction in serum creatinine and elevation in TG level as well as reductions in the kidney NO(x) concentration and MDA production level and increase in GSH concentration compared to CyA-treated control rats. Moreover, histopathology of the kidney of CyA-treated diabetics showed typical changes of the diabetic controls revealing glomerular hypertrophy and tubular dilation. On the other hand, treatment with CyA to those diabetic animals administered VS in the drinking water resulted in exacerbation of renal dysfunction, manifested by significant increases in serum indices of nephrotoxicity, cholesterol, TG and bilirubin levels. Also, VS administration to CyA-treated diabetics showed significant increase in kidney NO(x) concentration compared to those CyA-treated diabetics drinking plain tap water, and to a level significantly lower than those CyA-treated controls. Histopathologically, kidney of CyA/VS-treated diabetic showed marked CyA related changes. In conclusion, STZ-induced diabetes might provide partial protection against CyA-induced renal dysfunction. Also, treatment of hyperglycemia with VS might exacerbate CyA related nephrotoxicity.

Low serum magnesium is associated with decreased graft survival in patients with chronic cyclosporin nephrotoxicity

Hypomagnesaemia is a common side effect of cyclosporin A (CsA) therapy. Animal studies suggest that magnesium (Mg) supplementation inhibits chronic CsA nephropathy. To determine if low Mg levels correlate with true CsA-induced nephrotoxicity in humans, we examined kidney transplant biopsy records at our centre for all transplant biopsies performed between 1990 and 2002. We simultaneously reviewed the medical records to determine whether serum Mg levels were checked at the time of biopsy. Those individuals with histologically proven CsA nephrotoxicity were studied. Serum total Mg levels were available for 320 patients, 60 of whom were diagnosed with chronic CsA-mediated nephropathy. Patients were divided in two groups, a low Mg [n = 29, 1.8 (1.67-1.9) mg/dl or 0.74 (0.68-0.78) mmol/l] and a normal Mg group [n = 31, 2.2 (2.0-2.4) mg/dl or 0.9 (0.82-0.98) mmol/l, P<0.05] based on the median Mg level in the entire cohort (2 mg/dl or 0.82 mmol/l). Both groups were analysed for disease progression and graft loss using the slope of creatinine clearance (CCR) and multivariate analyses. Although the CCR at the time of biopsy was greater in the low Mg group [44.3 (36.3-64.3) ml/min vs 37.8 (25.2-47.3) ml/min, P<0.05), the decline in graft function was faster in this group (-8.9+/-3.5 vs 1+/-2.7 ml/min/year; P = 0.02) compared with the normal Mg cohort. Using Cox proportional hazards analyses, the adjusted graft survival was significantly reduced in the low Mg group 5 years after biopsy. Our study demonstrates that low serum Mg levels were associated with a faster rate of decline in kidney allograft function and increased rates of graft loss in renal transplant recipients with chronic CsA nephropathy. This suggests that hypomagnesaemia could potentiate CsA-mediated nephropathy.

Resveratrol, a polyphenolic phytoalexin protects against cyclosporine-induced nephrotoxicity through nitric oxide dependent mechanism

Cyclosporine A (CsA) is a potent and effective immunosuppressive agent, but its use is frequently accompanied by severe renal toxicity. The causes for the nephrotoxicity of CsA have not been fully elucidated. Intrarenal vasoconstriction induced by several different mediators, both in humans and experimental animals have been proposed. The present study was designed to investigate the possible protective effect of resveratrol on CsA-induced nephrotoxicity and to explore the possible mechanism involved in resveratrol's effect. Eight groups of rats were employed in this study, group 1 served as control, group 2 rats were treated with olive oil (vehicle for CsA), group 3 rats were treated with CsA (20 mg/kg, s.c. for 21 days), groups 4, 5 and 6 received CsA along with resveratrol (2, 5 and 10 mg/kg, p.o. 24 h before and 21 days concurrently), respectively, group 7 rats were treated with NOS inhibitor, L-NAME (10 mg/kg) along with resveratrol and CsA and group 8 rats received L-NAME along with CsA. CsA administration for 21 days resulted in a marked renal oxidative stress, significantly deranged the renal functions, reduced the tissue and urine nitrite levels and markedly altered the renal morphology. Treatment with resveratrol (5 and 10 mg/kg) significantly improved the renal dysfunction; tissue and urine total nitric oxide levels, renal oxidative stress and prevented the alterations in renal morphology. Concurrent administration of L-NAME blocked the protective effect of resveratrol indicating that resveratrol exerts its protective effect by releasing nitric oxide. These results clearly demonstrate the pivotal role of nitric oxide in etiology of CsA nephrotoxicity and indicate the renoprotective potential of resveratrol in CsA nephrotoxicity.

Methoxyethyl-Modified Intercellular Adhesion Molecule-1 Antisense Phosphorothiateoligonucleotides Inhibit Allograft Rejection, Ischemic-Reperfusion Injury, and Cyclosporine-Induced Nephrotoxicity

The addition of phosphorothioate (PS) groups to natural phosphodiester (PD) antisense oligodeoxynucleotides (oligo) prevents their in vivo hydrolysis by nucleases allowing an RNase-dependent elimination of targeted mRNA. To further improve oligo function 2'-methoxyethyl (ME) groups were attached to selected nucleotides at the 3'-end because ME groups block RNase activity. ME modification of PS- or PD/PS-oligo targeting human intracellular adhesion molecule (ICAM)-1 mRNA significantly increased the degree and duration of the in vitro inhibitory effects without compromising selectivity and specificity. A 7-day intravenous or oral therapy with rat ME/PS-modified ICAM-1 antisense oligo extended the survivals of kidney allografts. In addition, ME/PS-modified ICAM-1 antisense oligo reduced ischemic-reperfusion injury in kidneys, as measured by glomerular filtration rate, creatinine levels, and infiltration with leukocytes. Finally, a 14-day treatment with cyclosporine (CsA)-induced nephrotoxicity in syngeneic kidney transplants correlated with both increased ICAM-1 protein expression and infiltration with leukocytes. Graft perfusion and treatment of recipients with ICAM-1 antisense ME/PS-oligo alleviated the nephrotoxic effect and decreased ICAM-1 expression and leukocyte infiltration. ME/PS-modified ICAM-1 antisense oligo is very effective in inhibiting the ICAM-1-dependent mechanism of graft infiltration and tissue damage involved in allograft rejection, ischemic-reperfusion injury, and CsA-induced nephrotoxicity.

Comparative Study on the Effects of Cyclosporin A in Renal Cells in Culture

Background: Although cyclosporin A (CSA) inhibits P-glycoprotein (ABCB1), the relationship between this inhibition and CSA-induced nephrotoxicity is not established. Methods: Three renal cell lines were used to investigate the effects of CSA in cellular viability and accumulation of rhodamine 123 (Rho123): LLC-PK1, which does not express ABCB1 substantially; MDCK, expressing moderate amounts of this protein, and Ma104 cells, which express high amounts of ABCB1. Results: The viability was significantly reduced in the three cell lines after treatment with CSA concentrations >10 µM. Ma104 was the more resistant and LLC-PK1 the more sensitive. CSA increased Rho123 accumulation in the three cell lines when incubated simultaneously, MDCK presenting the higher increase. However, different results were achieved when the periods of incubation with Rho123 and CSA were disconnected: a post-incubation with CSA was more effective in Ma104 cells, while MDCK and LLC-PK1 showed no difference between pre-, co- and post-incubation with CSA. Conclusions: Our results suggest that the effects of CSA may be divided into two groups: ABCB1-independent (direct injury), and ABCB1-dependent toxicity, due to modulation of its activity. This could result in increased accumulation of noxious ABCB1 substrates, contributing to CSA-induced nephrotoxicity. Furthermore, the mechanisms of ABCB1 modulation by CSA may be different for different cell lines.

Increased Excretion of Urinary 20-HETE in Rats With Cyclosporine-Induced Nephrotoxicity

The present study examined the contribution of 20-hydroxy-5,8,11,14-eicosatetraenoic acid (20-HETE) in cyclosporine A (CsA)-induced renal nephrotoxicity. Treatment of rats with CsA (50 mg/kg) for 9 days induced renal damage as indicated by marked increase in urine flow (from 9.0 ± 0.3 ml/day to 46.6 ± 7.1 ml/day) and a 3 – 5-fold rise in blood urea nitrogen (BUN) levels. The urinary excretion of 20-HETE increased from 164 ± 5 ng/day (N = 5) to 2432 ± 290 ng/day (N = 5, P<0.01) after 9 days of CsA treatment. The increase in the urinary excretion of 20-HETE in the CsA treated rats was highly correlated with the increase in BUN levels (r = 0.819, P<0.001) and urine volume (r = 0.832, P<0.001). Immunohistochemical examination of kidney revealed that expression of cytochrome P450 4A (CYP4A) protein was markedly enhanced in the proximal tubules of CsA-treated rats. These results indicate that CsA-induced nephrotoxicity in rats is associated with a marked elevation in the renal production of 20-HETE and that 20-HETE may contribute to the pathophysiological condition of CsA-induced nephrotoxicity.

Change in Renal Heme Oxygenase Expression in Cyclosporine A-induced Injury

Cyclosporine A (CsA) is the first immunosuppressant used in allotransplantation. Its use is associated with side effects that include nephrotoxicity. This study explored the anatomic structures involved in CsA nephrotoxicity and the effect of heme oxygenase (HO) in preventing CsA injury. Rats were divided into four groups, which were treated with olive oil, CsA (15 mg/kg/day), CsA plus the HO inhibitor (SnMP; 30 microM/kg/day), and with the HO inducer (CoPP; 5 mg/100 g bw). Renal tissue was treated for morphological, biochemical, and immunohistochemical studies. CsA-treated rats showed degenerative changes with renal fibrosis localized mainly around proximal tubules. Collapsed vessels were sometimes seen in glomeruli. No HO-1 expression and increased expression of endothelin-1 (ET-1) were observed in CsA-treated rats compared with controls. In CsA plus SnMP-treated rats, HO-1 expression was further reduced and the morphology was not changed compared to the CsA group, whereas CsA plus CoPP-treated animals again showed normal morphology and with restoration and an increase in HO-1 levels. HO activity and immunohistochemical data showed similar alterations as HO expression. No changes were observed for HO-2 analysis. The observations indicate that HO-1 downregulation and ET-1 upregulation by CsA might be one mechanism underlying CsA-induced nephrotoxicity. Therefore, attempts to preserve HO levels attenuate CsA nephrotoxicity.

Effect of tacrolimus and cyclosporine on renal microcirculation and nitric oxide production

Objectives Cyclosporine (CSA) and tacrolimus (TAC) frequently induce nephrotoxicity and similar pathologic changes. Acute CSA-induced nephrotoxicity has been reported to be mediated by activation of vasoconstrictors such as endothelin. The purpose of the present study was to investigate the acute effects of TAC and CSA on the renal microcirculation and upon a vasodilator such as nitric oxide (NO) production. Methods Renal blood flow (RBF) in the microcirculation was measured by a Laser Doppler flow meter in uninephrectomised rats. RBF, mean arterial pressure (MAP), and renal vascular resistance (RVR) were measured in the following groups: (a) TAC (0.1 to 2.0 mg/kg/h, n = 3∼6); CSA (20 and 50 mg/kg/h, n = 5); (b) L-NAME (10 mg/kg), an NO synthase inhibitor, 8 minutes prior to TAC (0.5 and 1.5 mg/kg/h, n = 5), or CSA (20 and 50 mg/kg/h, n = 5). Stable NO end-products, serum NO 2 and NO 3, were measured by the Griess method ( n = 5). Results None of the parameters were changed by TAC alone, whereas TAC with L-NAME significantly reduced RBF (−28 ± 7%) and increased RVR (46 ± 17%) in a dose-dependent manner. CSA alone significantly reduced RBF (−37 ± 6%) and increased RVR (69 ± 22%) without any changes in MAP. The effects of CSA were enhanced by L-NAME. Serum concentration of NO 2 + NO 3 was significantly reduced by both L-NAME alone and CSA (50 mg/kg) ( P < .05), while there were no changes with TAC (1.5 mg/kg). Conclusions Blockade of NO production enhance the vasoconstrictive effect of CSA, and unmasked such an effect of TAC. These results suggest that the nephrotoxicity of CSA and TAC may involve the NO system.

Effect of epigallocatechin gallate on renal function in cyclosporine-induced nephrotoxicity

Introduction Nephrotoxicity is a clinically important side effect of cyclosporine (CsA). CsA-induced nephrotoxicity results from increased production of free radical species in the kidney. Epigallocatechin gallate (EGCG) acts as an antioxidant, thus, EGCG may have a protective effect on the alteration of renal function resultant from oxygen free radicals. The purpose of the present study was to investigate the protective effect of EGCG in a rodent model. Methods Experiments were performed on 3 groups. The normal control group (group 1) received normal saline solution. The CsA-treated group (group 2; 15 mg/kg body weight/d for 14 days) received subcutaneous injections. The EGCG-treated group (group 3) in addition received 25 mg of EGCG/kg body weight by intraperitoneal injection. Results There were significant increases in levels of blood urea nitrogen (BUN)(42.8 ± 8.2 mg/dL; P < .001), serum creatinine (1.18 ± 0.60 mg/dL; P < .05), and serum malondialdehyde (3.09 ± 0.20 nmol/mL; P < .001), and a significant decrease in CCr(0.07 ± 0.02 mL/min; P < .001) in group 2 compared with group 1. Levels of BUN (30.2 ± 0.7 mg/dL; P < .01)and CCr (0.12 ± 0.08 mL/min) were lower in group 3 than in group 2. Serum creatinine (0.71 ± 0.04 mg/dL) and serum malondialdehyde level (2.13 ± 0.15; P < .001 nmol/mL) were lower in group 3 than in group 2. There was no significant difference in CsA levels between group 2 (6.86 ± 1.48 μg/mL) and group 3 (6.69 ± 0.62 μg/mL). Conclusions EGCG treatment significantly protected renal function and free radical–mediated injury in the kidney from CsA-induced changes.

Electroporation-mediated HGF gene transfer ameliorated cyclosporine nephrotoxicity

The clinical utility of cyclosporine A (CsA) has been limited by its nephrotoxicity, which is characterized by tubular atrophy, interstitial fibrosis, and progressive renal impairment. Hepatocyte growth factor (HGF) has been reported to protect and salvage from renal injury as a renotropic and antifibrotic factor. Here, we investigated protective effects of HGF gene therapy on rat CsA-induced nephrotoxicity using electroporation-mediated gene transfer. CsA was subcutaneously administered daily under low sodium diet, and HGF gene was transferred into skeletal muscle by electroporation on days 7 and 14. We also examined the antiapoptotic mechanism of HGF using human proximal tubular epithelial cells. HGF gene transfer rescued CsA-induced initial tubular injury and suppressed interstitial infiltration of ED-1-positive macrophages in CsA-induced nephrotoxicity. In addition, HGF significantly inhibited tubular cell apoptosis, and increased the number of proliferating tubular epithelial cells. In vitro studies suggest that HGF executes the antiapoptotic function by enhancing the phosphorylation of Akt and Bcl-2. Northern blot analysis demonstrated that HGF gene transfer suppressed cortical mRNA levels of transforming growth factor-beta (TGF-beta). Consequently, HGF gene transfer significantly reduced a striped interstitial phenotypic alteration and fibrosis. We demonstrated that HGF gene transfer reduced CsA-induced tubular cell apoptosis and interstitial fibrosis. HGF gene transfer could be a potential strategy for preventing renal fibrosis.

Direct transfer of hepatocyte growth factor gene into kidney suppresses cyclosporin A nephrotoxicity in rats.

The clinical utility of cyclosporin A (CsA) has been limited by its nephrotoxicity, which is characterized by tubular atrophy, interstitial fibrosis and progressive renal impairment. Hepatocyte growth factor (HGF), which plays diverse roles in the regeneration of the kidney following acute renal failure, has been reported to protect against and salvage renal injury by acting as a renotropic and anti-fibrotic factor. Here, we investigated protective effects of HGF gene therapy on CsA-induced nephrotoxicity by using an electroporation-mediated gene transfer method. CsA was orally administered as a daily dose of 30 mg/kg in male Sprague-Dawley rats receiving a low sodium diet (0.03% sodium). Plasmid vector encoding HGF (200 micro g) was transferred into the kidney by electroporation. HGF gene transfer resulted in significant increases in plasma HGF levels. Morphological assessment revealed that HGF gene transfer reduced CsA-induced initial tubular injury and inhibited interstitial infiltration of ED-1-positive macrophages. In addition, northern blot analysis demonstrated that cortical mRNA levels of TGF-beta and type I collagen were suppressed in the HGF group. Finally, HGF gene transfer significantly reduced striped interstitial phenotypic alterations and fibrosis in CsA-treated rats, as assessed by alpha-smooth muscle actin expression and Masson's trichrome staining. These results suggest that HGF may prevent CsA-induced tubulointerstitial fibrosis, indicating that HGF gene transfer may provide a potential strategy for preventing renal fibrosis.

Transgenic mice overexpressing cyclophilin A are resistant to cyclosporin A-induced nephrotoxicity via peptidyl-prolyl cis– trans isomerase activity

Cyclosporin A (CsA) suppresses immune reaction by inhibiting calcineurin activity after forming complex with cyclophilins and is currently widely used as an immunosuppressive drug. Cyclophilin A (CypA) is the most abundantly and ubiquitously expressed family member of cyclophilins. We previously showed that CsA toxicity is mediated by ROS generation as well as by inhibition of peptidyl-prolyl cis– trans isomerase (PPIase) activity of CypA in CsA-treated myoblasts [FASEB J. 16 (2002) 1633]. Since CsA-induced nephrotoxicity is the most significant adverse effect in its clinical utilization, we here investigated the role of CsA inhibition of CypA PPIase activity in its nephrotoxicity using transgenic mouse models. Transgenic mice of either wild type (CypA/wt) or R55A PPIase mutant type (CypA/R55A), a dominant negative mutant of CypA PPIase activity, showed normal growth without any apparent abnormalities. However, CsA-induced nephrotoxicity was virtually suppressed in CypA/wt mice, but exacerbated in CypA/R55A mice, compared to that of littermates. Also, life expectancy was extended in CypA/wt mice and shortened in CypA/R55A mice during CsA administration. Besides, CsA-induced nephrotoxicity was inversely related to the levels of catalase expression and activity. In conclusion, our data provide in vivo evidence that supplement of CypA PPIase activity allows animal’s resistance toward CsA-induced nephrotoxicity.

Cyclosporine-a induced nephrotoxicity is associated with decreased renal bone morphogenetic protein-7 expression in rats

The aim of our study was to investigate bone morphogenetic protein-7 (BMP-7) expression in a rat model of chronic cyclosporine (CsA) toxicity compare with healthy controls, as well as the influence of treatment with the angiotensin-converting enzyme inhibitor (ACEI) quinapril. Twenty-four male Wistar rats were divided into groups of eight animals treated with CsA (15 mg/kg intraperitoneally) for 8 weeks (CsA group) without or with quinapril (10 mg/kg per day in the drinking water: CsA group + Q) for comparison with healthy controls (H group). The renal tissues were examined by light microscopy for CsA toxicity; specifically, tubulointerstitial damage and afferent arteriolopathy as well as BMP-7 expression were semiquantitatively scored by immunohistochemical staining. Mean CsA levels were 1982 ng/mL and 1968 ng/mL for the CsA and CsA + Q groups, respectively. At the end of the study period, the mean serum creatinine levels were 0.8 ± 0.2 mg/dL, 1.6 ± 0.8 mg/dL, and 1.4 ± 0.8 mg/dL for the H, CsA, and CsA + Q groups, respectively. Interstitial fibrosis, tubular atrophy, and afferent arteriolar hyalinization were present in the CsA group and, to a lesser degree, in the CsA + Q group, compared with the H group. CsA-treated rats displayed significantly decreased BMP-7 expression compared with healthy controls (P < .0005). BMP-7 expression was higher among the CsA + Q group than the the group CsA group. In a rat model histologic changes characteristic of CsA-induced nephrotoxicity are associated with decreased expression of BMP-7, which seems to be at least partially restored by ACE inhibition.

Does allopurinol prevent side effects of cyclosporine a treatrment?

Side effects of cyclosporine A (CsA) treatment, such as vasoconstriction and reduced renal plasma flow, are partly endothelium-dependent. Allopurinol improves endothelial function in diabetic and hypertensive patients. We examined the effects of allopurinol-application (50 mg/kg over 14 days) on arterial blood pressure, renal blood flow and vasoreactivity of CsA-treated (8 mg/kg over 14 days) Wistar rats. Mean arterial pressure (MAP) of CsA-treated rats was 106 ± 4 mmHg (MAP of CsA + allopurinol-treated rats: 103 ± 4 mmHg), renal plasma flow was 6.3 ± 1.5 ml/min in CsA-treated rats as compared to 5.3 ± 1.1 ml/min in rats treated with CsA + allopurinol. Bolus injection of norfenefrin (0.1 mg/kg) increased MAP to 168 ± 9 (CsA-group) and to 128 ± 8 mmHg (CsA + allopurinol-group). The elevation of blood pressure was significantly higher in the CsA-treated-group than in the CsA+allopurinol-treated animals (62 ± 6 vs. 24 ± 5 mmHg, p<0.05), while renal plasma flow decreased to 1.3 ± 0.5 (CsA-group) and to 3.5 ± 0.7 ml/min respectively (CsA + allopurinol-group). The difference of the decrease of renal plasma flow between the groups was significant (p<0.05). Allopurinol seems to have beneficial effects on vasoreactivity and renal blood flow in CsA-treated animals and might attenuate CsA-induced nephrotoxicity.

Cyclosporin A Prevents the Hypoxic Adaptation by Activating Hypoxia-inducible Factor-1α Pro-564 Hydroxylation

The mechanism by which hypoxia induces gene transcription involves the inhibition of hypoxia-inducible factor (HIF)-1alpha prolyl hydroxylase activity, which prevents von Hippel-Lindau (vHL)-dependent targeting of HIF-1alpha to the ubiquitin-proteasome pathway. HIF-1alpha is stabilized, translocates to the nucleus, interacts with hypoxia-responsive elements, and promotes the activation of target genes. This report shows that cyclosporin A (CsA) interferes with the hypoxic signaling cascade in C6 glioma cells. CsA inhibits hypoxia-dependent gene transcription in a reporter gene assay and prevents the hypoxic accumulation of HIF-1alpha. Addition of the 530-603 C-terminal oxygen-dependent degradation (ODD) domain of HIF-1alpha to the green fluorescent protein (GFP) destabilized the protein in an oxygen-dependent manner. CsA prevented the hypoxic stabilization of an ODD.GFP fusion protein. An assay for 2-oxoglutarate-dependent dioxygenases was developed using a light mitochondrial kidney fraction as a source of enzyme. It uses the capacity of specific peptides to stimulate the degradation of [(14)C]2-oxoglutarate. CsA stimulated the enzymatic activity in the presence of a peptide that mimicked the 557-576 sequence of HIF-1alpha. The enzyme promoted [(35)S]vHL binding to glutathione S-transferase (GST).ODD fusion protein. This association increased in the presence of CsA. CsA effects were not observed when the proline residue corresponding to Pro-564 in the HIF-1alpha sequence was replaced by a hydroxyproline or an alanine residue. Finally, CsA increased vHL-ODD interaction during hypoxia. We conclude that CsA destabilizes HIF-1alpha by promoting hydroxylation of Pro-564 in the ODD domain. Such a mechanism may prevent hypoxic adaptation during CsA-induced nephrotoxicity and contribute to the adverse effects of this drug.

Synergistic effects of mycophenolate mofetil and losartan in a model of chronic cyclosporine nephropathy.

Combined treatments of mycophenolate mofetil (MMF) and losartan (LSRT) have synergistic effects on various renal diseases through their hemodynamic and anti-inflammatory effects. This study investigated whether MMF treatment is effective in inhibiting inflammatory processes in chronic cyclosporine A (CsA) nephrotoxicity, and whether combined treatment using MMF and LSRT affords superior protection compared with the respective monotherapies. Rats on a low-salt diet were given vehicle (VH group, olive oil, 1 mg/kg per day), CsA (15 mg/kg per day), CsA and LSRT (CsA+LSRT group, 100 mg/L per day), CsA and MMF (CsA+MMF group; 40 mg/kg per day), or CsA, LSRT and MMF (CsA+LSRT MMF group). Control groups received each drug without CsA treatment. Renal function, histologic parameters (arteriolopathy, tubulointerstitial fibrosis, and inflammatory cell infiltration), and mediators of CsA-induced nephrotoxicity (angiotensin-II, osteopontin, and transforming growth factor [TGF]-beta1) were studied. The CsA-treated rats showed decreased renal function and increased histologic parameters compared with the VH-treated rats. The CsA+MMF treatment significantly improved renal function and histopathologic parameters compared with the CsA group, and combined treatment with MMF and LSRT further improved those parameters compared with the CsA+LSRT and CsA+MMF groups. At a molecular level, increased expression of angiotensin II protein, osteopontin, and TGF-beta1 mRNAs in the CsA group were significantly decreased with MMF, and further decrease was observed with the combined treatment using MMF and LSRT. MMF treatment decreases CsA-induced nephrotoxicity, and combined treatment with LSRT has a synergistic effect in preventing chronic CsA nephrotoxicity.

Attenuation of Cyclosporine-Induced Renal Dysfunction by Catechin: Possible Antioxidant Mechanism

One of great use of immunosuppressant, Cyclosporine-A (CsA) is in the solid organ transplantation; however the extensive use of this is cautionable due to its toxic effect in renal tissue, characterized by the tubular atrophy, interstitial fibrosis, and progressive renal impairment. However, there are many mediators are associated with pathogenesis of nephrotoxicity of CsA, the exact mechanism is still in debate. Recent studies indicate that Reactive Oxygen Species (ROS) induced oxidative stress and lipid peroxidations are the important mechanisms implicated in the pathophysiology of nephrotoxicity with CsA. In the present study we examined effect of dietary flavonoid catechin on oxidative damage in cyclosporine-A induced nephrotoxicity. Chronic administration of CsA (20 mg/kg/day) subcutaneously for 21 days significantly decreased the body weight as compared with vehicle treated rats. CsA (20 mg/kg/day) administration for 21 days significantly decreased the renal function by increase in the serum creatinine, blood urea nitrogen, and decrease in the creatinine and urea clearance as compared with vehicle treated rats. Catechin (100 mg/kg/day) for 21 days along with CsA significantly reversed the changed renal parameters, however lower dose of catechin (50 mg/kg/day) restored only increased serum creatinine levels as compared with CsA alone treated group. Biochemical analysis revealed that chronic administration of CsA (20 mg/kg/day) for 21 days significantly induced lipid peroxidation and decreased the glutathione levels in the kidney homogenate of rats. It is also observed that chronic CsA administered rats showed decrease in antioxidant defense enzyme superoxide dismutase and increase in the catalase activity as compared with vehicle treated rats. Co-administration of catechin (100 mg/kg/day) orally along with CsA for 21 days significantly reduced the lipid peroxidation and restored the decreased glutathione levels as compared with CsA alone group, but lower dose of catechin (50 mg/kg/day) restored only decreased glutathione levels induced by CsA. Co-administration of only higher dose of catechin (100 mg/kg/day) along with CsA significantly increased the superoxide dismutase (SOD) levels as compared with CsA alone treated group. It is also observed that catechin (100 mg/kg/day) along with CsA further increased the catalase levels as compared with CsA alone treated group, but not with lower dose of catechin. Animals administered with catechin (100 mg/kg/day) alone for 21 days showed significant increase in the catalase levels as compared with vehicle treated group. The major findings of the present study suggest that oxidative stress might play a significant role in CsA-induced nephrotoxicity. In conclusion, dietary administration of flavonoid catechin could be a useful component for the prevention/treatment of CsA-induced nephrotoxicity.