Benefit and cost from the long-term use of cyclosporine-A in idiopathic membranous nephropathy.

AIM: Idiopathic membranous nephropathy (IMN), the most common cause of nephrotic syndrome in adults, is usually treated by cyclosporin A (CsA). Estimation of the effectiveness of long-term use of CsA in the remission and relapse rate of nephrotic syndrome along with histological changes in repeat renal biopsies was the aim of the study. METHODS: Thirty-two nephrotic patients with well-preserved renal function treated by prednisolone and CsA were studied. A repeat biopsy was performed in 18 patients with remission of nephrotic syndrome, after 24 months of treatment, to estimate the activity of the disease and features of CsA toxicity. RESULTS: Complete remission of nephrotic syndrome was observed in 18 (56%) and partial remission in 10 patients (31%) after 12 months of treatment (total 87%). Relapses were observed in 39% and 60% of patients with complete and partial remission, respectively, and multiple relapses in 25% of patients, who showed gradual unresponsiveness to CsA and decline of renal function. Progression of stage of the disease and more severe glomerulosclerosis and tubulointerstitial injury were recognized in 55% and 61% of patients respectively. Features of CsA nephrotoxicity were not observed. The severity of histological changes was related to the time elapsed from the first biopsy (r = 0.452, P < 0.05). CONCLUSION: Low doses of CsA with prednisolone induce remission of nephrotic syndrome in most idiopathic membranous nephropathy patients. Although typical features of CsA nephrotoxicity are not observed, significant deterioration of histological lesions occurs with time, even in patients with remission. Long-term use of CsA should be examined with caution.

Urinary Transforming Growth Factor-beta 1 as a marker of response to immunosuppressive treatment, in patients with crescentic nephritis.

BACKGROUND: Crescentic nephritis is characterized by formation of cellular crescents that soon become fibrotic and result in irreversible damage, unless an effective immunosuppressive therapy is rapidly commenced. TGF-beta1 is involved in the development of crescents through various pathways. The aim of this study was to identify whether the determination of urinary TGF-beta1 levels in patients with crescentic nephritis could be used as a marker of response to treatment. METHODS: Fifteen patients with crescentic nephritis were included in the study. The renal expression of TGF-beta1 was estimated in biopsy sections by immunohistochemistry and urinary TGF-beta1 levels were determined by quantitative sandwich enzyme immunoassay (EIA). TGF-beta1 levels were determined at the time of renal biopsy, before the initiation of immunosuppressive treatment (corticosteroids, cyclophosphamide and plasma exchange). Twelve patients with other types of proliferative glomerulonephritis and ten healthy subjects were used as controls. RESULTS: Improvement of renal function with immunosuppressive therapy was observed in 6 and stabilization in 4 patients (serum creatinine from 3.2 +/- 1.5 to 1.4 +/- 0.1 mg/dl and from 4.4 +/- 1.2 to 4.1 +/- 0.6 mg/dl, respectively). In 5 patients, with severe impairment of renal function who started on dialysis, no improvement was noted. The main histological feature differentiating these 5 patients from others with improved or stabilized renal function was the percentage patients with poor response to treatment were the percentage of glomeruli with crescents and the presence of ruptured Bowman's capsule and glomerular necrosis. Urinary TGF-beta1 levels were significantly higher in patients who showed no improvement of renal function with immunosuppressive therapy (930 +/- 126 ng/24 h vs. 376 +/- 84 ng/24 h, p < 0.01). TGF-beta1 was identified in crescents and tubular epithelial cells, whereas a significant correlation of TGF-beta1 immunostaining with the presence of fibrocellular cresents was observed (r = 0.531, p < 0,05). CONCLUSION: Increased TGF-beta1 renal expression and urinary excretion that is related to the response to immunosuppressive therapy was observed in patients with crescentic nephritis. Evaluation of urinary TGF-beta1 levels may be proved a useful marker of clinical outcome in patients with crescentic nephritis.

Expression of apoptosis-related proteins bcl-2 and bax along with transforming growth factor (TGF-beta1) in the kidney of patients with glomerulonephritides.

BACKGROUND: Apoptosis, a gene-directed form of cell death, has been involved in the resolution of renal injury but also in the development of scarring. Bcl-2 and bax are proteins related to apoptotic process that either provides a survival advantage to rapidly proliferating cells (bcl-2) or promote cell death by apoptosis (bax). Various cytokines and growth factors are involved in this process. This study investigates the expression of bcl-2 and bax and the presence of apoptotic bodies in relation to the TGF-beta1 expression at the time of diagnosis in the renal biopsies of patients with glomerulonephritis (GN). METHODS: Fifty patients with various types of GN and ten controls were included in the study. Bcl-2, bax and Transforming Growth Factor (TGF-beta1) positive cells were detected in kidney biopsies by immunohistochemistry, while apoptotic cells were detected by in situ end labeling of fragmented DNA (ISEL). Morphometric analysis was used for quantitation of immunostaining. RESULTS: The intensity of bcl-2, bax and TGF-beta1 immunostaining in the renal tissue of patients with GN was significantly more to the observed in the control biopsies. Bcl-2 and bax were expressed within the epithelial cells of proximal, distal and collecting tubules and in the renal interstitium. Bax and bcl-2 proteins were also identified within the glomeruli in a few patients but their distribution was not related to the type of GN. TGF-beta1 was expressed in the cytoplasm of tubular epithelial cells and to a lesser extent in the renal interstitium and glomeruli. A positive correlation of TGF-beta1 with the extent of bax immunostaining (r=0.498, p<0.05) and an inverse correlation with that of bcl-2 (r= -0.490, p<0.05) were identified. Apoptotic bodies were identified only in the renal tissue of patients with GN and were mainly localized among tubular epithelial and interstitial cells. CONCLUSION: The intensity of bcl-2 and bax proteins expression and the presence of apoptotic bodies in the renal tissue of patients with GN suggest that apoptotic process is ongoing during the evolution of renal disease. The correlation of TGF-beta1 expression with that of apoptosis-related proteins might represent an implication of this growth factor with apoptotic process in the human diseased kidney.

Histologic change of peritoneal membrane in relation to adequacy of dialysis in continuous ambulatory peritoneal dialysis patients.

BACKGROUND: Long-term exposure of peritoneal membrane to bioincompatible dialysis solutions leads to structural changes and loss of ultrafiltration capability. OBJECTIVE: We studied the possible relationship between histologic change and the transport characteristics of peritoneal membrane and adequacy of dialysis in continuous ambulatory peritoneal dialysis (CAPD) patients. PATIENTS AND METHODS: The study included 18 CAPD patients (11 men, 7 women) who underwent a peritoneal biopsy either at initiation of treatment (group A, n = 9) or after a mean of 4 years on CAPD (group B, n = 9). The morphologic changes in the mesothelial cells and the vascular compartment and the thickness of the submesothelial collagenous zone were estimated and compared with observations from 6 patients with normal renal function who underwent biopsy of the parietal peritoneum during abdominal surgery. The relationship of the observed changes in CAPD patients to results from a peritoneal equilibration test (PET) and to adequacy of dialysis [total weekly creatinine clearance (CCr) and Kt/V urea] were also investigated. RESULTS: The main histologic changes in both groups of patients were loss of mesothelial cells and decrease in the normal mesothelial surface, thickening of the submesothelial collagenous zone, and presence of vascular hyalinosis. The thickness of the submesothelial collagenous zone in both groups of patients was significantly greater than that found in controls (410 mum and 580 mum vs 50 mum, p < 0.05). Although no significant difference was found between morphologic change in the peritoneal membrane of uremic patients starting on CAPD and those who had been on peritoneal dialysis (PD) for a mean period of 4 years, a trend was observed toward more severe lesions in the latter patients. The PET, CCr, and Kt/V urea were not significantly different in the two groups of patients. Those parameters also showed no significant changes when examined at initiation of CAPD and after a mean of 4 years of PD in the same patients (group B). No significant correlations were observed between the histologic changes and the PET, CCr, or Kt/V in both groups of patients. CONCLUSIONS: Significant structural changes are observed in the peritoneal membrane of uremic patients, and those changes become worse with CAPD treatment. Structural changes are not followed by functional changes during the first 4 years on CAPD.

Apoptosis and myofibroblast expression in human glomerular disease: a possible link with transforming growth factor-beta-1.

BACKGROUND/AIMS: The pathophysiological pathways involved in the pathogenesis and evolution of renal fibrosis, have not been fully elucidated. Transforming growth factor-beta(1) (TGF-beta(1)) is involved in the development of renal scarring. Apoptosis is responsible for intrinsic cell deletion observed in end-stage kidney disease. Myofibroblasts are involved in the development of renal fibrosis. This study investigates whether there is a potential relationship between apoptosis, myofibroblast infiltration and TGF-beta(1) expression in the kidney of patients with glomerulonephritis (GN). METHODS: Forty patients with various types of GN were included in the study. Myofibroblasts and TGF-beta(1) positive cells were detected in kidney biopsies by immunohistochemistry, while apoptotic cells were detected by the in situ end labelling of fragmented DNA. RESULTS: Myofibroblasts were identified in the glomeruli of some patients with severe mesangioproliferative GN and glomerulosclerosis but a more intensive myofibroblast expression was found in the renal interstitium. TGF-beta(1) was expressed in the cytoplasm of tubular epithelial cells, in the renal interstitium and in the glomeruli of patients with GN. Apoptotic cells were mainly detected in the tubules and interstitium and were present in areas with intense myofibroblast infiltration. Positive correlations were observed between the intensity of myofibroblast expression in the interstitium and apoptosis in the tubulointerstitial area (r = 0.521, p < 0.01) as well as TGF-beta(1) expression (r = 0.462, p < 0.05) and degree of renal impairment (r = 0.430, p < 0.05). CONCLUSIONS: These observations suggest that myofibroblast infiltration and apoptosis along with TGF-beta(1) expression are associated with the development of interstitial fibrosis in patients with glomerular disease.