CsA Nephrotoxicity Research Articles

Kaempferol attenuates cyclosporine-induced renal tubular injury via inhibiting the ROS-ASK1-MAPK pathway.

Cyclosporine (CSA) is a widely used immunosuppressive medication. CSA nephrotoxicity severely limits its application. Kaempferol (KPF), a naturally occurring phenolic compound, has a promising protective effect in reducing CSA-induced renal tubular injury, but the mechanism remains unknown. Our study aimed to determine the protective role of KPF against CSA-induced renal tubular injury. C57/B6 mice and the NRK-52E cell line were employed. CSA worsened renal function in mice, causing detachment and necrosis of tubular cells, leading to tubular vacuolation and renal interstitial fibrosis. CSA caused the detachment, rupture, and death of tubular cells in vitro, resulting in cell viability loss. KPF mitigated all these injurious alterations. KPF hindered CSA-induced ROS generation and protected renal tubular epithelial cells, similar to the antioxidant NAC. CSA lowered SOD activity and GSH levels while increasing MDA levels, and KPF ameliorated these changes. CSA caused phosphorylation of ASK1, JNK, and p38, similar to H2O2, whereas KPF significantly inhibited these changes. In conclusion, KPF reduces CSA-induced tubular epithelial cell injury via its antioxidant properties, inhibits the phosphorylation of ASK1, and inhibits the phosphorylation of p38 and JNK, implying that the synergistic use of KPF in CSA immunotherapy may be a promising option to reduce CSA-evoked renal injury.

Selenium-enriched Bifidobacterium longum DD98 significantly improves the efficacy of Mesalazine and Cyclosporin A in colitis mice

The incidence of ulcerative colitis (UC) is increasing worldwide and therapeutic drugs for UC are limited. Improvement of microbiome composition with the use of probiotics has the potential to increase the therapeutic index of UC drugs. Several lines of evidence suggested that Bifidobacterium significantly improve colitis by restoring the altered gut microbiota in DSS-treated mice, however the adjuvant effect of Bifidobacterium with UC drugs remains unknown. In this study, we tested the adjuvant potential of probiotic selenium-enriched Bifidobacterium Longum DD98 (SeDD98) on Mesalazine and Cyclosporin A (CsA) two medications used in the treatment of UC. We found that SeDD98 significantly improved the efficacy of Mesalazine and CsA in UC. The combination of SeDD98 and CsA showed the strongest efficacy in decreasing colitis histological scores, inflammation, and oxidative stress. Next we demonstrated that the combination of SeDD98 and CsA shifted the gut microbiota composition and increased with higher alpha diversity as well as beneficial bacteria such as Ruminococcaceae_UCG-014 and Lachnospiraceae_NK4A136. In parallel, we assessed if the adjuvant of SeDD98 with CsA had an impact on CsA-induced kidney injury which represents one of the major side effects. We found that SeDD98 significantly improved CsA nephrotoxicity in UC mice. We then validated this observation using chronic kidney disease (CKD) mice induced by CsA administration. These results demonstrated that SeDD98 in combination with CsA was associated with increased efficacy and reduced nephrotoxicity altogether, providing the scientific basis for the adjuvant therapy of probiotics in UC.

Cyclosporine-induced kidney damage was halted by sitagliptin and hesperidin via increasing Nrf2 and suppressing TNF-α, NF-κB, and Bax

Cyclosporine A (CsA) is employed for organ transplantation and autoimmune disorders. Nephrotoxicity is a serious side effect that hampers the therapeutic use of CsA. Hesperidin and sitagliptin were investigated for their antioxidant, anti-inflammatory, and tissue-protective properties. We aimed to investigate and compare the possible nephroprotective effects of hesperidin and sitagliptin. Male Wistar rats were utilized for induction of CsA nephrotoxicity (20 mg/kg/day, intraperitoneally for 7 days). Animals were treated with sitagliptin (10 mg/kg/day, orally for 14 days) or hesperidin (200 mg/kg/day, orally for 14 days). Blood urea, serum creatinine, albumin, cystatin-C (CYS-C), myeloperoxidase (MPO), and glucose were measured. The renal malondialdehyde (MDA), glutathione (GSH), catalase, and SOD were estimated. Renal TNF-α protein expression was evaluated. Histopathological examination and immunostaining study of Bax, Nrf-2, and NF-κB were performed. Sitagliptin or hesperidin attenuated CsA-mediated elevations of blood urea, serum creatinine, CYS-C, glucose, renal MDA, and MPO, and preserved the serum albumin, renal catalase, SOD, and GSH. They reduced the expressions of TNF-α, Bax, NF-κB, and pathological kidney damage. Nrf2 expression in the kidney was raised. Hesperidin or sitagliptin could protect the kidney against CsA through the mitigation of oxidative stress, apoptosis, and inflammation. Sitagliptin proved to be more beneficial than hesperidin.

Četrdeset godina ciklosporina u kliničkoj praksi

Cyclosporine (CsA) was discovered in the lab of Sandoz in Switzerland in 1972. while searching for an antifungal drug. However, it quickly became an irreplaceable immunosuppressive drug for renal and other solid organ transplantation. It has been found, in the initial experiments, that CsA inhibits both in vitro cell-mediated lysis and lymphocyte sensitization by allogeneic target cells. Clinical trials have demonstrated better one-year graft survival after cadaveric renal transplants when receiving CsA instead of azathioprine. Although improvement has been observed in the rates of one-year renal graft survival and acute rejection, but long-term graft survival rate did not improve. This can be attributed to the nephrotoxic effects of the CsA. This issue is a consequence of hemodynamic effects on renal blood flow and glomerular filtration, effect on renal tubular function and blood vessels. Along with nephrotoxicity, CsA also causes other adverse effects such as hypertension, gingival hyperplasia, hyperkalemia, hypomagnesemia, hyperlipidemia, neurotoxicity, and in some cases thrombotic microangiopathies. However, in recent years CsA nephrotoxicity has been looked at from a different angle, where it has been linked to high CsA doses that used to be administered. Following its use in solid organ transplantation, CsA has been found to have an important role in treating systemic connective tissue diseases, as well as its consequences, primary glomerulonephritis, inflammatory bowel disease, and psoriasis. CsA effectiveness in treating above mentioned diseases is still greater than its side effects, which makes it a base of treatment options for numerous diseases.

2-Methoxyestradiol TPGS Micelles Attenuate Cyclosporine A-Induced Nephrotoxicity in Rats through Inhibition of TGF-β1 and p-ERK1/2 Axis.

The immunosuppressant cyclosporine A (CSA) has been linked to serious renal toxic effects. Although 2-methoxyestradiol (2ME) possesses a wide range of pharmacological abilities, it suffers poor bioavailability after oral administration. The purpose of this study was to evaluate the potential of 2ME loaded D-ɑ-tocopheryl polyethylene glycol succinate (TPGS) micelles to prevent CSA-induced nephrotoxicity in rats. A 2ME-TPGS was prepared and showed particle size of 44.3 ± 3.5 nm with good entrapment efficiency and spherical structures. Male Wistar rats were divided into 5 groups, namely: Control, Vehicle, CSA, CSA + 2ME-Raw, and CSA + 2ME-Nano. CSA was injected daily at a SC dose of 20 mg/kg. Both 2ME-Raw and 2ME-Nano were given daily at oral doses of 5 mg/kg. Treatments continued for three successive weeks. 2ME-TPGS exerted significant protective effects against CSA nephrotoxicity. This was evidenced in ameliorating deterioration of renal functions, attenuation of pathological changes in kidney tissues, exerting significant anti-fibrotic, antioxidant, and anti-inflammatory effects together with significant anti-apoptotic effects. Western blot analyses showed both 2ME-Raw and 2ME-Nano significantly inhibited protein expression of TGF-β1 and phospho-ERK (p-ERK). It was observed that 2ME-TPGS, in almost all experiments, exerted superior protective effects as compared with 2ME-Raw. In conclusion, 2ME loaded in a TPGS nanocarrier possesses significant protective activities against CSA-induced kidney injury in rats. This is attributable to 2ME anti-fibrotic, antioxidant, anti-inflammatory, and anti-apoptotic activities which are mediated at least partly by inhibition of TGF-β1/p-ERK axis.

Multi‐omics analysis reveals regulatory mechanisms in chronic cyclosporine A‐induced nephrotoxicity studied a rat model

Chronic calcineurin inhibitor (CNI) nephrotoxicity is a major drawback in current immunosuppressive regimens. In the chronic setting, arteriolar hyalinosis, decreased glomerular filtration rate, interstitial fibrosis and tubular dedifferentiation are the major adverse side effects. Since CsA is still widely used in transplant recipients, particularly in posttransplant diabetes, mechanistic insights into nephrotoxic mechanisms are required. To identify regulatory mechanisms in CsA nephrotoxicity we used quantitative transcriptomic, proteomic and phosphoproteomic methods. We tested the hypothesis that tubulointerstitial pathomechanisms play a predominant role in chronic CNI nephropathy. Whole transciptome RNA‐seq as well as global proteomic and phosphoproteomic methodologies were performed on kidney extracts from normal Wistar rats receiving CsA (25mg/kg b.w./day) or vehicle for 3 weeks. Differentially expressed genes and proteins as well as their phosphorylation status were obtained. Products of interest were tested using Western blot, qPCR, and immunohistochemistry. CsA treatment stimulated genome‐wide alterations in rat kidney according to RNA‐seq data. We identified 342 transcripts upregulated (padj<0.05) which included Ribosome (padj<0,0001) and Oxidative phosphorylation (padj<0,0001) pathways, whereas 331 transcripts were downregulated, with enrichment in genes critical for amino acid metabolism. Data were controlled by the established upregulation of renin and downregulation of calbindin (pdaj<0,05) in global proteomics. KEGG pathway and GO analysis from proteomics largely corresponded to the RNA‐seq results. Upregulated proteins were further related to ECM‐receptor interaction and focal adhesion pathways (padj<0,05). Phosphoproteomics demonstrated functional phosphorylation of components from unfolded protein response pathways, indicating an activation of the integrated stress response upon CsA. Products were verified at the tissue‐ and cell level. In sum, using integrated ‐omics analysis in CsA nephrotoxicity proved to be a powerful approach. Chronic CsA treatment was associated with enhanced energy metabolism and activation of the unfolded protein‐response pathways. A tubulointerstitial focus has been demonstrated. Potential biomarker candidates have been obtained.

Cyclosporine A but not tacrolimus induces pro‐apoptotic endoplasmic reticulum stress in renal tubular cells

Calcineurin inhibitors (CNI), cyclosporine A (CsA) or tacrolimus (Tac), belong to the first‐line immunosuppressive strategies in organ‐transplanted patients. Both CNI may exert renal side effects, which are typically stronger in patients receiving CsA. Continued clinical demand for CsA requires improved understanding of its nephrotoxicity. Calcineurin inhibition by CsA occurs via complexes with cyclophilins, whereas Tac recruits FKBP12 instead. We hypothesized that impaired chaperone function of cyclophilins may aggravate CsA cytotoxicity due to induction of endoplasmic reticulum (ER) stress and pro‐apoptotic unfolded protein response (UPR). To address this hypothesis, effects of CsA vs. Tac (10 µM for 6 h) on the UPR signaling were evaluated in cultured human embryonic kidney cells (HEK293), human renal proximal tubular (PT) epithelial cells (HRPTEpC), and isolated rat PTs using quantitative PCR, immunoblotting, and immunofluorescence staining. An established ER stress inducer, thapsigargin (Tg) served as a positive control. CsA and Tg, but not Tac, induced ER stress and pro‐apoptotic UPR in HEK293 cells, which was reflected by increased levels of key UPR products (BiP, CHOP, spliced XBP1, and phosphorylated IRE1a) and cleaved caspase 3 (cCas3). Similar effects were observed in HRPTEpC cells and isolated rat PTs. Knockdown of cyclophilin A or B isoforms in HEK293 cells using siRNA augmented CHOP and cCas3 to an extent comparable with CsA treatment suggesting relevance of cyclophilin activity for intact proteostasis. Application of chemical chaperones, TUDCA or 4‐PBA, alleviated the CsA‐induced UPR suggesting that boosting the protein folding may have protective effects against CsA cytotoxicity. Along the same line, genetic suppression of UPR in HEK293 cells by CRISPR/Cas9‐mediated deletion of the key ER stress sensors, PERK or ATF6, blunted the pro‐apoptotic UPR in response to CsA.In summary, these results suggest that nephrotoxic effects of CsA are partially mediated by suppression of cyclophilins, ER stress, and pro‐apoptotic UPR. Pharmacological modulation of UPR bears the potential to alleviate CsA nephrotoxicity.

Avocado Seeds Relieve Oxidative Stress-Dependent Nephrotoxicity but Enhance Immunosuppression Induced by Cyclosporine in Rats.

Cyclosporine A’s (CsA) immunosuppressive effect makes it an ideal drug for organ transplantation. However, CsA’s uses are restricted due to its side effects. We investigated the effects of avocado seed (AvS) powder on CsA-induced nephrotoxicity and immunosuppression in rats. The injection of CsA (5 mg/kg, subcutaneously, for 10 days) increased serum levels of creatinine, uric acid, and urea, and the renal levels of the malondialdehyde. It decreased creatinine clearance and the renal activity of antioxidant enzymes (superoxide dismutase, catalase, and glutathione peroxidase) and Na+/K+ ATPase. The administration of CsA also significantly downregulated the renal expression of interferon-gamma, tumor necrosis factor-alpha, interleukin 1 beta, monocyte chemotactic protein 1, intercellular adhesion molecule-1, and vascular cell adhesion molecule 1 genes, and increased renal DNA damage. Histopathological examination confirmed the biochemical and molecular alterations that accompanied CsA nephrotoxicity. All CsA-induced deleterious effects, except immunosuppression, were ameliorated by feeding rats on a basal diet supplemented with 5% AvS powder for 4 weeks. Importantly, AvS also maximized CsA’s immunosuppressive effect. These findings suggest a potential ameliorative effect of AvS on CsA-induced nephrotoxicity, and AvS enhances CsA’s immunosuppressive effect. Therefore, AvS might be used in combination with CsA in transplantation treatment to relieve the CsA-induced nephrotoxicity.

Long-Term Protection of CHBP Against Combinational Renal Injury Induced by Both Ischemia-Reperfusion and Cyclosporine A in Mice.

Renal ischemia–reperfusion (IR) injury and cyclosporine A (CsA) nephrotoxicity affect allograft function and survival. The prolonged effects and underlying mechanisms of erythropoietin derived cyclic helix B peptide (CHBP) and/or caspase-3 small interfering RNA (CASP-3siRNA) were investigated in mouse kidneys, as well as kidney epithelial cells (TCMK-1), subjected to transplant-related injuries. Bilateral renal pedicles were clamped for 30 min followed by reperfusion for 2 and 8 weeks, with/without 35 mg/kg CsA gavage daily and/or 24 nmol/kg CHBP intraperitoneal injection every 3 days. The ratio of urinary albumin to creatinine was raised by IR injury, further increased by CsA and lowered by CHBP at 2, 4, 6 and 8 weeks, whereas the level of SCr was not significantly affected. Similar change trends were revealed in tubulointerstitial damage and fibrosis, HMGB1 and active CASP-3 protein. Increased apoptotic cells in IR kidneys were decreased by CsA and CHBP at 2 and/or 8 weeks. p70 S6 kinase and mTOR were reduced by CsA with/without CHBP at 2 weeks, so were S6 ribosomal protein and GSK-3β at 8 weeks, with reduced CASP-3 at both time points. CASP-3 was further decreased by CHBP in IR or IR + CsA kidneys at 2 or 8 weeks. Furthermore, in TCMK-1 cells CsA induced apoptosis was decreased by CHBP and/or CASP-3siRNA treatment. Taken together, CHBP predominantly protects kidneys against IR injury at 2 weeks and/or CsA nephrotoxicity at 8 weeks, with different underlying mechanisms. Urinary albumin/creatinine is a good biomarker in monitoring the progression of transplant-related injuries. CsA divergently affects apoptosis in kidneys and cultured kidney epithelial cells, in which CHBP and/or CASP-3siRNA reduces inflammation and apoptosis.

Cyclosporine A blocks autophagic flux in tubular epithelial cells by impairing TFEB-mediated lysosomal function.

Cyclosporine A (CsA) is an immunosuppressor widely used for the prevention of acute rejection during solid organ transplantation. However, severe nephrotoxicity has substantially limited its long‐term usage. Recently, an impaired autophagy pathway was suggested to be involved in the pathogenesis of chronic CsA nephrotoxicity. However, the underlying mechanisms of CsA‐induced autophagy blockade in tubular cells remain unclear. In the present study, we observed that CsA suppressed the activation and expression of transcription factor EB (TFEB) by increasing the activation of mTOR, in turn promoting lysosomal dysfunction and autophagy flux blockade in tubular epithelial cells (TECs) in vivo and in vitro. Restoration of TFEB activation by Torin1‐mediated mTOR inhibition significantly improved lysosomal function and rescued autophagy pathway activity, suppressing TEC injury. In summary, targeting TFEB‐mediated autophagy flux represents a potential therapeutic strategy for CsA‐induced nephrotoxicity.

Angiotensin II receptor blockade alleviates calcineurin inhibitor nephrotoxicity by restoring cyclooxygenase 2 expression in kidney cortex.

The use of calcineurin inhibitors such as cyclosporine A (CsA) for immunosuppression after solid organ transplantation is commonly limited by renal side effects. CsA-induced deterioration of glomerular filtration rate and sodium retention may be related to juxtaglomerular dysregulation as a result of suppressed cyclooxygenase 2 (COX-2) and stimulated renin biosynthesis. We tested whether CsA-induced COX-2 suppression is caused by hyperactive renin-angiotensin system (RAS) and whether RAS inhibition may alleviate the related side effects. Rats received CsA, the RAS inhibitor candesartan, or the COX-2 inhibitor celecoxib acutely (3days) or chronically (3weeks). Molecular pathways mediating effects of CsA and RAS on COX-2 were studied in cultured macula densa cells. Pharmacological or siRNA-mediated calcineurin inhibition in cultured cells enhanced COX-2 expression via p38 mitogen-activated protein kinase and NF-kB signalling, whereas angiotensin II abolished these effects. Acute and chronic CsA administration to rats led to RAS activation along with reduced cortical COX-2 expression, creatinine clearance and fractional sodium excretion. Evaluation of major distal salt transporters, NKCC2 and NCC, showed increased levels of their activating phosphorylation upon CsA. Concomitant candesartan treatment blunted these effects acutely and completely normalized the COX-2 expression and renal functional parameters at long term. Celecoxib prevented the candesartan-induced improvements of creatinine clearance and sodium excretion. Suppression of juxtaglomerular COX-2 upon CsA results from RAS activation, which overrides the cell-autonomous, COX-2-stimulatory effects of calcineurin inhibition. Angiotensin II antagonism alleviates CsA nephrotoxicity via the COX-2-dependent normalization of creatinine clearance and sodium excretion.

Dehydroxymethylepoxyquinomicin, a novel nuclear factor-\u03baB inhibitor, prevents the development of cyclosporine A nephrotoxicity in a rat model

BackgroundCyclosporine A (CsA) is an essential immunosuppressant in organ transplantation. However, its chronic nephrotoxicity is an obstacle to long allograft survival that has not been overcome. Nuclear factor-κB (NF-κB) is activated in the renal tissue in CsA nephropathy. In this study, we aimed to investigate the effect of the specific NF-κB inhibitor, dehydroxymethylepoxyquinomicin (DHMEQ), in a rat model of CsA nephrotoxicity.MethodsWe administered CsA (15 mg/kg) daily for 28 days to Sprague-Dawley rats that underwent 5/6 nephrectomy under a low-salt diet. We administered DHMEQ (8 mg/kg) simultaneously with CsA to the treatment group, daily for 28 days and evaluated its effect on CsA nephrotoxicity.ResultsDHMEQ significantly inhibited NF-κB activation and nuclear translocation due to CsA treatment. Elevated serum urea nitrogen and creatinine levels due to repeated CsA administration were significantly decreased by DHMEQ treatment (serum urea nitrogen in CsA + DHMEQ vs CsA vs control, 69 ± 6.4 vs 113.5 ± 8.8 vs 43.1 ± 1.1 mg/dL, respectively, p < 0.0001; serum creatinine in CsA + DHMEQ vs CsA vs control, 0.75 ± 0.02 vs 0.91 ± 0.02 vs 0.49 ± 0.02 mg/dL, respectively, p < 0.0001), and creatinine clearance was restored in the treatment group (CsA + DHMEQ vs CsA vs control, 2.57 ± 0.09 vs 1.94 ± 0.12 vs 4.61 ± 0.18 ml/min/kg, respectively, p < 0.0001). However, DHMEQ treatment did not alter the inhibitory effect of CsA on urinary protein secretion. The development of renal fibrosis due to chronic CsA nephrotoxicity was significantly inhibited by DHMEQ treatment (CsA + DHMEQ vs CsA vs control, 13.4 ± 7.1 vs 35.6 ± 18.4 vs 9.4 ± 5.4%, respectively, p < 0.0001), and these results reflected the results of renal functional assessment. DHMEQ treatment also had an inhibitory effect on the increased expression of chemokines, monocyte chemoattractant protein-1, and chemokine (c-c motif) ligand 5 due to repeated CsA administration, which inhibited the infiltration of macrophages and neutrophils into the renal tissue.ConclusionsThese findings suggest that DHMEQ treatment in combination therapy with CsA-based immunosuppression is beneficial to prevent the development of CsA-induced nephrotoxicity.

Nephroprotective Potential of Mesenchymal Stromal Cells and Their Extracellular Vesicles in a Murine Model of Chronic Cyclosporine Nephrotoxicity.

BackgroundCell therapies and derived products have a high potential in aiding tissue and organ repairing and have therefore been considered as potential therapies for treating renal diseases. However, few studies have evaluated the impact of these therapies according to the stage of chronic kidney disease. The aim of this study was to evaluate the renoprotective effect of murine bone marrow mesenchymal stromal cells (BM-MSCs), their extracellular vesicles (EVs) and EVs-depleted conditioned medium (dCM) in an aggressive mouse model of chronic cyclosporine (CsA) nephrotoxicity in a preventive and curative manner.MethodsAfter 4 weeks of CsA-treatment (75 mg/kg daily) mice developed severe nephrotoxicity associated with a poor survival rate of 25%, and characterized by tubular vacuolization, casts, and cysts in renal histology. BM-MSC, EVs and dCM groups were administered as prophylaxis or as treatment of CsA nephrotoxicity. The effect of the cell therapies was analyzed by assessing renal function, histological damage, apoptotic cell death, and gene expression of fibrotic mediators.ResultsCombined administration of CsA and BM-MSCs ameliorated the mice survival rates (6–15%), but significantly renal function, and histological parameters, translating into a reduction of apoptosis and fibrotic markers. On the other hand, EVs and dCM administration were only associated with a partial recovery of renal function or histological damage. Better results were obtained when used as treatment rather than as prophylactic regimen i.e., cell therapy was more effective once the damage was established.ConclusionIn this study, we showed that BM-MSCs induce an improvement in renal outcomes in an animal model of CsA nephrotoxicity, particularly if the inflammatory microenvironment is already established. EVs and dCM treatment induce a partial recovery, indicating that further experiments are required to adjust timing and dose for better long-term outcomes.

Apocynin and catalase prevent hypertension and kidney injury in Cyclosporine A-induced nephrotoxicity in rats

Oxidative stress is involved in the pathogenesis of a number of diseases including hypertension and renal failure. There is enhanced expression of nicotinamide adenine dinucleotide (NADPH oxidase) and therefore production of hydrogen peroxide (H2O2) during renal disease progression. This study investigated the effect of apocynin, an NADPH oxidase inhibitor and catalase, an H2O2 scavenger on Cyclosporine A (CsA) nephrotoxicity in Wistar-Kyoto rats. Rats received CsA (25mg/kg/day via gavage) and were assigned to vehicle, apocynin (2.5mmol/L p.o.), catalase (10,000U/kg/day i.p.) or apocynin plus catalase for 14 days. Renal functional and hemodynamic parameters were measured every week, and kidneys were harvested at the end of the study for histological and NADPH oxidase 4 (NOX4) assessment. Oxidative stress markers and blood urea nitrogen (BUN) were measured. CsA rats had higher plasma malondialdehyde (by 340%) and BUN (by 125%), but lower superoxide dismutase and total antioxidant capacity (by 40%, all P<0.05) compared to control. CsA increased blood pressure (by 46mmHg) and decreased creatinine clearance (by 49%, all P<0.05). Treatment of CsA rats with apocynin, catalase, and their combination decreased blood pressure to near control values (all P<0.05). NOX4 mRNA activity was higher in the renal tissue of CsA rats by approximately 63% (P<0.05) compared to controls but was reduced in apocynin (by 64%), catalase (by 33%) and combined treatment with apocynin and catalase (by 84%) compared to untreated CsA rats. Treatment of CsA rats with apocynin, catalase, and their combination prevented hypertension and restored renal functional parameters and tissue Nox4 expression in this model. NADPH inhibition and H2O2 scavenging is an important therapeutic strategy during CsA nephrotoxicity and hypertension.

Urotensin receptor antagonist palosuran attenuates cyclosporine-a-induced nephrotoxicity in rats.

Cyclosporine-A (CsA) is widely used for immunosuppressive therapy in renal transplantation. Nephrotoxicity is the main dose-limiting undesirable consequence of CsA. Urotensin II (U-II), a novel peptide with a powerful influence on vascular biology, has been added to the list of potential renal vascular regulators. Upregulation of the urotensin receptors and elevation of plasma U-II levels are thought to possibly play a role in the etiology of renal failure. The present study examines this hypothesis by evaluating renal function and histology with regard to the potential role of U-II and its antagonist, palosuran, in the pathogenesis of CsA-induced nephrotoxicity in rats. Male Sprague-Dawley rats were treated with CsA (15 mg/kg, for 21 days, intraperitoneally) or CsA + palosuran (300 mg/kg, for 21 days). Renal function was measured and histopathology, U-II immunostaining and protein detection with western blotting of the kidneys were performed. Cyclosporine-A administration caused a marked decline in creatinine clearance (Ccr). Fractional sodium excretion (FENa) tended to increase in the CsA-treated rats. Plasma U-II levels decreased in the CsA-treated rats. Cyclosporine-A treatment resulted in a marked deterioration in renal histology and an increase in the expression of U-II protein in the kidneys. Palosuran's improvement of renal function manifested as a significant decrease in serum creatinine levels and a significant increase in urine creatinine levels, resulting in a marked increase in Ccr. Palosuran produced a significant normalization of kidney histology and prevented an increase in U-II expression. Cyclosporine-A-induced renal impairment was accompanied by an increase in U-II expression in kidneys and a contrary decrease in systemic U-II levels. Palosuran improved the condition of rats suffering from renal dysfunction by preventing the decrease in renal U-II expression without affecting the systemic levels of U-II. The protective effect of palosuran in CsA nephrotoxicity is possibly independent of its U-II receptor antagonism.

Cyclosporine A inhibits MRTF-SRF signaling through Na+/K+ ATPase inhibition and actin remodeling.

Calcineurin inhibitors (CNI) are the pillars of immunosuppression in transplantation. However, they display a potent nephrotoxicity whose mechanisms remained widely unsolved. We used an untargeted quantitative proteomic approach (iTRAQ technology) to highlight new targets of CNI in renal proximal tubular cells (RPTCs). CNI‐treated RPTCs proteome displayed an over‐representation of actin‐binding proteins with a CNI‐specific expression profile. Cyclosporine A (CsA) induced F‐actin remodeling and depolymerization, decreased F‐actin‐stabilizing, polymerization‐promoting cofilin (CFL) oligomers, and inhibited the G‐actin‐regulated serum response factor (SRF) pathway. Inhibition of CFL canonical phosphorylation pathway reproduced CsA effects; however, S3‐R, an analogue of the phosphorylation site of CFL prevented the effects of CsA which suggests that CsA acted independently from the canonical CFL regulation. CFL is known to be regulated by the Na+/K+‐ATPase. Molecular docking calculations identified two inhibiting sites of CsA on Na+/K+‐ATPase and a 23% decrease in Na+/K+‐ATPase activity of RPTCs was observed with CsA. Ouabain, a specific inhibitor of Na+/K+‐ATPase also reproduced CsA effects on actin organization and SRF activity. Altogether, these results described a new original pathway explaining CsA nephrotoxicity.

Pretransplant assessment of cyclosporine level as a predictor of cyclosporine dose requirements after kidney transplantation

Introduction and aimsPretransplant administration of cyclosporine (CsA) may reduce post-transplant maintenance dose and consequently CsA inhibitor nephrotoxicity and helps in achieving the desired target C2 levels earlier. The optimum dose or timing of administration of CsA induction dose is still debatable.Patients and methodsWe compared three different protocols for pretransplant administration of CsA aiming to reach a target C2 therapeutic level of greater than 800 ng/ml on the third day post-transplant. Sixty kidney transplant recipients from Cairo University hospitals were divided into: group 1 (n=20) who received a single CsA induction dose of 2 mg/kg 12 h pretransplant; group 2 (n=20) who received four CsA consecutive doses of 4 mg/kg 48 h pre-transplant; and group 3 (n=20) who received four CsA consecutive doses of 2 mg/kg 48 h pretransplant.ResultsThe desired therapeutic level in the earlier post-transplantation period was achieved in 65% in group 1, 100% in groups 2 and 3). In group 2 a lower dose was needed to maintain C2 within the therapeutic range during the first year post-transplantation (P<0.01). Furthermore, a lower number of cases were complicated by CsA nephrotoxicity in group 2 in comparison to groups 1 and 3 (25, 0, 5% in group 1, 2, 3, respectively, P<0.039). A higher longer dose of CsA pretransplant associated with early withdrawal of CsA had a better effect on graft function than lower or shorter induction doses with late withdrawal as evidenced by lower serum creatinine levels all through the follow-up period in group 2 compared with group 3.ConclusionForty-eight-hour pretransplant induction with CsA at a dose of 4 mg/kg with early dose reduction post-transplant was associated with lower CsA maintenance and a better 1-year graft function.

Metabolic Pathway of Cyclosporine A and Its Correlation with Nephrotoxicity.

Cyclosporine A (CsA) is widely used for organ transplantation and autoimmune disorders. However, CsA nephrotoxicity is a serious side effect that limits the clinical use of CsA. The metabolism of CsA has a close relationship with this disease in renal-transplant patients. However, the metabolic pathways of CsA and its metabolizing enzymes have rarely been comprehensively reviewed. In this review, we have summarized the specific metabolic profiles of CsA in humans, especially renal-transplant patients. Moreover, the specific metabolizing enzymes and the potential roles that CsA metabolism plays in CsA nephrotoxicity were summarized and discussed. Electronic databases including PubMed, Web of Science, and Scifinder were searched with the keywords "Cyclosporine A and metabolism", and "Cyclosporine A and nephrotoxicity", "Cyclosporine A metabolism and nephrotoxicity". All these studies published until 2018 were included in this review. The major metabolic pathways of CsA in humans are hydroxylation and N-demethylation. Normally, these metabolites are relatively less toxic than CsA. However, the metabolism of CsA in the kidneys is much weaker than that in the liver, which explains why CsA is so toxic to the kidneys. CYP3A families, especially CYP3A4 and CYP3A5, play an important role in the biotransformation of CsA. Moreover, increased lines of evidence show that some metabolites (including AM19) associate directly with nephrotoxicity in CsA-treated organ-transplant patients. The findings of this review help to further understand the metabolic activities of CsA in renal-transplant patients and cast some light on the mechanisms of CsA nephrotoxicity.

Upregulation of cystathionine-γ-lyase/hydrogen sulfide pathway underlies the celecoxib counteraction of cyclosporine-induced hypertension and renal insult in rats

We recently reported that celecoxib, a selective cyclooxygenase-2 (COX2) inhibitor, counteracts the adverse circulatory and renal actions of cyclosporine (CSA). Despite the seemingly advantageous nature of this interaction particularly in clinical settings that necessitate the combined use of the two drugs such as immune-related arthritis, the underlying mechanism remains elusive. This prompted us to test the hypothesis that the facilitation of the cystathionine-γ-lyase (CSE)/hydrogen sulfide (H2S) signaling accounts for such favorable effects of celecoxib on CSA nephrotoxicity. The data showed that the 10-day co-treatment of rats with celecoxib (10 mg/kg/day) ameliorated the hypertensive and biochemical and renal structural damages caused by CSA (20 mg/kg/day). Celecoxib also reversed the CSA-evoked (i) reductions in the tubular and glomerular protein expression of CSE and levels of H2S, prostaglandin E2 (PGE2), and total antioxidant capacity (TAC), and (ii) increases in inflammatory (tumor necrosis factor-α, TNF-α), fibrotic (transforming growth factor-β1, TGF-β1) and apoptotic (caspase-3) cytokines. These celecoxib effects disappeared when rats were treated concomitantly with the CSE inhibitor DL-propargylglycine (DL-PAG), indicating the importance of the CSE-derived H2S in mediating the renoprotective action of celecoxib. This view is bolstered by the observation that the beneficial hemodynamic and renal actions of celecoxib were replicated after supplementation of rats with sodium sulfide (Na2S, H2S donor). Together, the increased abundance of renal CSE and H2S and subsequent dampening down of inflammatory, fibrotic, oxidant, and apoptotic pathways play pivotal roles in the capacity of celecoxib to compromise the troublesome hypertensive and nephrotoxic insults caused by CSA in rats.

A novel elastin-like polypeptide drug carrier for cyclosporine A improves tear flow in a mouse model of Sjögren's syndrome

As a potent macrolide immunosuppressant, cyclosporine A (CsA) is used to treat multiple autoimmune diseases, including non-autoimmune and autoimmune-mediated dry eye disease, rheumatoid arthritis and psoriasis. Despite its potency, CsA has poor solubility, poor bioavailability, and can cause serious adverse reactions such as nephrotoxicity and neurotoxicity. To overcome these limitations, we invented a new strategy to carry CsA by fusing its cognate human receptor, cyclophilin A (CypA), to a 73 kDa elastin-like polypeptide (ELP) termed A192 using recombinant protein expression. Derived from human tropoelastin, ELPs are characterized by the ability to phase separate above a temperature that is a function of variables including concentration, molecular weight, and hydrophobicity. The resultant fusion protein, termed CA192, which assembles into a dimeric species in solution, effectively binds and solubilizes CsA with a Kd of 189 nM, comparable to that of endogenous CypA with a Kd of 35.5 nM. The release profile of CsA from CA192 follows a one phase decay model with a half-life of 957.3 h without a burst release stage. Moreover, CA192-CsA inhibited IL-2 expression induced in Jurkat cells through the calcineurin-NFAT signaling pathway with an IC50 of 1.2 nM, comparable to that of free CsA with an IC50 of 0.5 nM. The intravenous pharmacokinetics of CA192 followed a two-compartment model with a mean residence time of 7.3 h. Subcutaneous administration revealed a bioavailability of 30% and a mean residence time of 15.9 h. When given subcutaneously for 2 weeks starting at 14 weeks in male non-obese diabetic (NOD) mice, a model of autoimmune dacryoadenitis used to study Sjögren's syndrome (SS), CA192-CsA (2.5 mg/kg, every other day) significantly (p = 0.014) increased tear production relative to CA192 alone. Moreover, CA192 delivery reduced indications of CsA nephrotoxicity relative to free CsA. CA192 represents a viable new approach to deliver this effective but nephrotoxic agent in a modality that preserves therapeutic efficacy but suppresses drug toxicity.