Nonrejection pathology of renal allograft biopsies: 10 years experience from a tertiary care center in north India.

Background: Renal dysfunction in allograft transplant is common and its assessment is done using Revised Banff '97 working classification, which is the accepted formulation for the evaluation of histological appearance of renal allograft biopsies. The nonrejection category under the Banff working classification of renal allograft pathology forms a large group resulting in allograft dysfunction. Aim: To evaluate the spectrum of histopathological changes seen in renal allograft dysfunction. Materials and Methods: A total of 119 renal biopsies were studied over 10 years presenting with renal allograft dysfunction from a tertiary center in North India. Results: Majority of the biopsies were in the nonrejection category (47.1%), which included few cases of acute tubular necrosis (25.2%), cyclosporine nephrotoxicity (16%), infections (10.9%), and thrombotic microangiopathy (3.4%). The second largest category in our study was acute/active cellular rejection group (31.9%), which displayed moderate to severe tubulitis, mononuclear cell infiltrate in the interstitium, and vasculitis. Antibody-mediated rejection cases were seen in 28.6% of the renal biopsies followed by chronic allograft nephropathy cases (12.6%) showing features of tubular atrophy and interstitial fibrosis. Borderline changes with features of mild tubulitis contributed to 7.6% of the biopsies. The smallest group comprised of only 4.2%, which were within normal histological limits. Conclusion: Timely accurate diagnosis of renal allograft dysfunction is essential for prompt, effective management of renal transplant patients. Thus, nonrejection pathology forms a significant cause of renal dysfunction in patients with renal allograft transplantation.

Expression of angiotensin II and its receptors in a rat model of chronic cyclosporine nephrotoxicity / 第二军医大学学报

Objective: To observe the expression of angiotensin II ( Ang II) and its receptors in a rat model of chronic cyclosporine (CsA) nephrotoxicity. Methods: Chronic CsA nephrotoxicity was induced in Sprague-Dawley rats by administering CsA (15 mg/kg s. c.) for 4 weeks. The body weight, systolic blood pressure, serum CsA, serum creatinine (Cr), and creatinine clearance rate (Ccr) of rats were examined in each group. Trichrome staining was used to observe the tubulointerstitial fibrosis; expressions of Ang II and its receptors (AT1 and AT2) were examined by immunohistochemical staining and Western blotting analysis. Results: Compared with the control rats, CsA-treated rats showed decreased body weight, increased Cr, decreased Ccr and tubulointerstitial fibrosis (P < 0.01). Immunohistochemistry revealed that the immunoreactivity of Ang II was significantly increased in the CsA-treated rats (47±7 vs 13±4, P < 0.01), with the immunoreactivity mainly locating to the juxtaglomerular afferent arterioles, and the immunoreactivity was significantly correlated with tubulointerstitial fibrosis (r=0. 769, P<0.001). Western blotting analysis showed significantly decreased AT1 expression ([114±14]% vs [42±6]%, P<0.01) and increased AT2 expression ([129±23]% vs [469±43]%, P<0.01). Conclusion: The findings of our study suggest that the intrarenal renin-angiotensin system is activated during chronic CsA nephrotoxicity, which is manifested by increased Ang II immunoreactivity, and this increased immunoreactivity is closely related to tubulointerstitial fibrosis.

Effect of Cyclosporine Withdrawal on Apoptotic Cell Death in a Model of Chronic Cyclosporine Nephrotoxicity / 대한신장학회잡지

BACKGROUND: Cyclosporine (CsA) used in a dual or triple regimen is the current primary immunosuppressant for prevention of renal allograft rejection. Although the introduction of CsA into clinical practice has resulted in a 10 to 15% increase of the 1-year graft survival rate, little has been gained to improve long-term graft survival. Long-term administration of CsA causes a progressive renal failure, a renal striped interstitial fibrosis, a tubular atrophy, and a hyalinosis of the afferent arteriole. Previous studies have shown that apoptotic cell death is increased in CsA-treated kidneys and plays a role in interstitial fibrosis. This study evaluates the effect of CsA withdrawal on CsA nephrotoxicity. METHODS: Sprague-Dawley rats on low-salt diet had been treated with CsA (7.5 mg/kg/day) for five weeks and then CsA had been withdrawn for the next five weeks. The weights, systolic blood pressure, plasma CsA concentration, renal function (serum creatinine, creatinine clearance) and histologic parameter (arteriolopathy, interstitial fibrosis) of the rats were compared. Apoptotic cell death was detected by TUNEL assay. RESULTS: CsA-treated rats showed decreased renal function compared with vehicle (VH) group. With CsA withdrawal, renal function was significantly improved compared with the CsA-treated rats. CsA-treated rats showed increased arteriolopathy and interstitial fibrosis compared with VH group. With CsA withdrawal, renal histology was significantly improved. CsA-treated rats showed increased TUNEL-positive cell compared with VH group. With CsA withdrawal, apoptotic cell death was decreased. Using bivariate correlation analysis, CsA induced apoptotic cell death correlated with arteriolopathy and interstitial fibrosis. CONCIUSION: CsA withdrawal in CsA nephrotoxicity decreased apoptotic cell death and improved renal function and renal histiology. This finding provides a rationale for CsA withdrawal in CsA nephrotoxicity. Further investigation should be directed to explore the effects of the accumulated CsA dose and the timing of CsA withdrawal for regression CsA nephrotoxicity.

-Melanocyte Stimulating Hormone (MSH) decreases cyclosporine A induced apoptosis in cultured human proximal tubular cells

The pathogenesis of chronic cyclosporine A (CsA) nephrotoxicity has not been elucidated, but apoptosis is thought to play an important role in CsA induced tubular atrophy. Recently Fas-Fas ligand system mediated apoptosis has been frequently reported in many epithelial cells as well as in T lymphocytes. We investigated the ability of CsA to induce apoptosis in cultured human proximal tubular epithelial cells and also the effect of -MSH on them. Fas, Fas ligand, and an intracellular adaptor protein, Fas-associating protein with death domain (FADD) expression, and poly-ADP ribose polymerase (PARP) cleavage were also studied. CsA induced apoptosis in cultured tubular epithelial cells demonstrated by increased number of TUNEL positive cells and it was accompanied by a significant increase in Fas mRNA and Fas ligand protein expressions. FADD and the cleavage product of PARP also increased, indicating the activation of caspase. In -MSH co-treated cells, apoptosis markedly decreased with downregulation of Fas, Fas ligand and FADD expressions and also the cleavage product of PARP. In conclusion, these data suggest that tubular cell apoptosis mediated by Fas system may play a role in tubular atrophy in chronic CsA nephrotoxicity and pretreatment of -MSH may have a some inhibitory effect on CsA induced tubular cell apoptosis.

The Effect of Mycophenolate Mofetil on Chronic Rejection after Renal Transplantation / 대한이식학회지

BACKGROUND: Although chronic rejection remains the leading cause of late graft failure, the pathophysiology of the phenomena is not completely understood and no specific treatment is available. The new immunosuppressive agent, mycopheonolate mofetil (MMF), has been effective for treatment of acute rejection and acute refractory rejection after renal transplantation. MMF has been thought to have potential effects on chronic rejection because it can inhibit arterial smooth muscle cell proliferation and antibody synthesis and also inhibit lymphocytes recruitment to the inflammatory site by diminishing activity of adhesion molecule. But there have been only a few reports about its effect on chronic rejection. METHODS: Thirty-three renal transplant patients with chronic rejection which was clinically suspected or biopsy proven were enrolled in this study. Patients who have taken azathioprine as one of their immunosuppressive regimen discontinued azathioprine and all patients added MMF to their immunosuppresants. We reduced cyclosporine doses on some patients according to their cyclosporine blood level. Before the change of immunosuppresive regimen, the mean serum creatinine was 1.94+/- 0.37 mg/dl. The mean follow up period after the change of immunosuppresants was 6.57+/- 2.1 months. RESULTS: After this MMF trial, mean serum creatinine was significantly decreased during the follow up period as compared with the pretreatment value (at months 1, 1.82 +/-0.33 mg/dl, at months 3, 1.76 +/-0.38 mg/dl, at months 6, 1.73+/- 0.33 mg/dl; Vs baseline of 1.94+/- 0.37 mg/dl, P<0.05, at respectively). The dosage of cyclosporine, as intended, was significantly reduced from 232 54 mg/dl to 210 51 mg/dl after 6 months observation period (p<0.01). There was no episode of acute rejection after starting MMF with a reduction in cyclosporine. CONCLUSION: With this clinical trial, we propose that MMF may be effective for prevention of progression of chronic rejection. By addition of MMF, we could reduce the cyclosporine doses without risk of acute rejection and we suggest that it may have an important role for prevention of chronic cyclosporine nephrotoxicity.

Apoptosis on Acute Cyclosporine Nephrotoxicity in Rat / 대한내과학회지

OBJECTIVES: Apoptosis is a physiologic or programmed cell death in contrast with necrotic cell death. Recently it has been known that apoptosis are concerned in the effects of chemotherapeutic agents or radiation therapy on tumor cells. Cyclosporine a(CsA), a potent immunosuppressant, has been effectively used in organ transplantaion, but it also has a significant toxicity in the kidneys. However the exact mechanism of CsA nephrotoxicity has not been ellucidated yet. This study was performed to investigate whether apoptosis particiates in CsA nephrotoxicity or not. METHODS: Twenty seven Sprague-Dawley rats were divided into 5 groups. 1) Vehicle group(n=7) as a control: Cremopbor 50mg/kg/day/subcutaneously (sc) for 7 days, 2) CsA4 group(n=5): CsA 50mg/kg/day/sc for 4 days, 3) CsA7 group(n=5): CsA 50mg/kg/day/sc for 7 days, 4) R4 group(n=5): 4 days after CsA 50mg/kg/day/se for 7 days, and 5) R8 group(n=5): 8 days after CsA 50mg/kg/day/sc for 6 days, Biochemical parameters including blood pressure were measured in each group and the cell count of apoptosis in rat kidney was evaluated by in situ end labelling(ISEL) method. RESULTS: 1) The increase of serum creatinine, blood pressure and decrease of creatinine clearance appeared in CsA4 and CsA7 groups. 2) The ce11 counts of apoptosis on tubular cells in CsA4 and CsA7 groups were significantly increased more than in control group(79.0 +/- 16.9, 98.4 +/- 11.4 vs 35.4 +/- 8.8, p0.05), 3) The cell count of apoptosis on the interstitium in each group was not significantly different from that in control group(p>0.05). 4) The cell count of apaptosis on tubular cells was increased more than that on the interstitium in all groups. 5) The cell count of apoptosis on cortex only in CsA7 group was significantly increased more than that io control group(57.8 +/- 11.5 vs 21.8 +/- 2.6, p<0.05), 6) The cell count of apoptosis on medulla only in CsA4 group was significantly increased more than that in control group(636. +/- 17.9 vs 22.6 +/- 9.7, p<0.05). 7) Total cell counts of apoptosis only in CsA4 and CsA7 groups were significantly increased more than in contral group(96.0 +/- 21.1, 99.8 +/- 11.8 vs 46.6 +/- 11.4, p<0.05). CONCLUSION: CsA caused apoptosis mainly on tubular cells rather than the interstitial cells and apoptotic cells in CsA nephrotoxicity were not increased during the recovery phase. With the results apoptosis may play an important role in CsA nephrotoxicity.

Light microscopic and electron microscopic features of cyclosporine nephrotoxicity in rats

In order to clarify morphologic changes associated with cyclosporine (CS) nephrotoxicity, CS in ethyl alcohol at 25 mg/kg/day i.p. was administered to male Sprague-Dawley rats for periods of 1 to 8 weeks. Mean systolic BP was slightly increased in the CS group at 4 weeks (p < 0.05), but there was no difference compared to a control group at 8 weeks. Blood urea nitrogen was significantly elevated at 4 weeks and continued to rise (p < 0.005), whereas serum creatinine was elevated at 8 weeks. Microscopic examination of the kidneys from CS-treated rats at one week revealed cytoplasmic vacuolization in all segments of the proximal tubules, tubular inclusion bodies, and peritubular capillary congestion. Ultrastructurally, some vacuoles were neutral fat droplets, while others appeared as single membrane-bound structures due to dilatation of the endoplasmic reticulum. The tubular inclusion bodies were enlarged autolysosomes filled with distorted mitochondrial fragments. At two weeks, tubular regeneration was prominent, in addition to the above mentioned toxic tubulopathy. At four weeks, focal areas of interstitial fibrosis and tubular atrophy associated with cystic dilatation were seen. At 8 weeks, interstitial and intratubular microcalcification were present, in addition to patchy foci of interstitial fibrosis, but vascular lesions were not demonstrated. Although renal tubular changes characterized by vacuolization, inclusion bodies, and microcalcification and interstitial fibrosis are not specific for CS toxicity, these changes are commonly found in both humans and rats at high doses of CS.