Albumin upregulates eNOS mRNA through ETRA/B in human proximal tubular epithelial cells.

BACKGROUND: Proximal tubular cells respond to proteinuria by expressing several cytokines and inflammatory molecules that induce interstitial fibrosis. Increased attention has been drawn toward the systems of endothelin (ET) and nitric oxide (NO). This work contributes to the elucidation of the interplay between these two systems in proximal tubular epithelial cells (PTECs) after exposure in proteinuric conditions. METHODS: HK-2 cells, a human PTEC line, were incubated with albumin, simulating proteinuric conditions. Cells were then lysed and either total RNA was isolated or whole cell extracts were prepared. PreproET-1, ET receptors (ETRA and ETRB) and NO synthases (eNOS, iNOS) mRNA accumulation was estimated by RT-PCR, and proteins by Western blot analysis. NO production was assessed using Griess reaction. Furthermore, we treated HK-2 cells with NO donor sodium nitroprusside, NO inhibitor L-NAME, ETRA inhibitor BQ123, ETRB inhibitor BQ788 and purified ET-1, and investigated the potential interplay between albumin-induced stimulation of NO or ET-1 systems. RESULTS: We found that albumin upregulates preproET-1, ETRA, ETRB, eNOS and iNOS mRNA as well as protein and stimulates NO production. Additionally, we recorded an ETRA/B dependent regulation of albumin-induced eNOS expression. CONCLUSIONS: For the first time an in vitro albumin-induced ET-1 and NO interplay was revealed.

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.

Interaction of endothelin-1 and nitric oxide pathways in human tubular epithelial cells under the influence of cyclosporine-A.

BACKGROUND: The exact mechanism of cyclosporine (CsA) nephrotoxicity has not been clarified. In this study, we investigated the effect of pharmacological doses of CsA on the production of nitric oxide synthases (NOSs) and endothelin (ET) receptors (ETR-A, ETR-B), in human tubular cells [human kidney (HK)-2], to identify any implication of these pathways in CsA nephrotoxicity. METHODS: Human tubular epithelial cells (HK-2) were cultured in the presence of CsA at various concentrations (0-1000 ng/mL). Reverse transcriptase-polymerase chain reaction (RT-PCR) was used to determine mRNA synthesis of NOSs (eNOS, iNOS) and ET receptors (ETR-A, ETR-B) and western blot analysis for the subsequent proteins. RESULTS: A dose-dependent induction of synthesis of NO synthases eNOS and iNOS and ET receptors ETR-A and ETR-B was observed, even at therapeutic doses of CsA. An interaction between NO and ET-1 systems under the influence of CsA was also observed. Blockage of NO production was followed by down-regulation of ETR-B whereas blockade of ET pathway with ET receptor antagonists was followed by down-regulation of eNOS expression. CONCLUSION: CsA induces NOSs as well as ET receptor mRNA and protein synthesis in tubular epithelial cells. The up-regulation of NO and ET-1 pathways is probably implicated in the nephrotoxic action of CsA, whereas an interplay between ETR-B and eNOS seems to be involved.

The prognostic value of frozen section preimplantation graft biopsy in the outcome of renal transplantation.

INTRODUCTION: Preimplantation biopsy provides a window on the state of the renal allograft. In this study, the prognostic value of frozen section preimplantation graft biopsy was estimated and compared to regularly processed formalin-fixed biopsy. MATERIALS AND METHODS: Seventy-four renal allograft recipients were studied. The degree of glomerulosclerosis, acute tubular necrosis, interstitial fibrosis, arteriosclerosis, and arteriolosclerosis was rapidly estimated in frozen sections and correlated to the renal function in the immediate posttransplantation period and 3 months thereafter. The histological changes were also examined in paraffin-embedded sections. RESULTS: The histological changes observed in rapidly processed frozen sections were comparable to those observed on regularly processed sections and their differences did not reach statistical significance. Glomerulosclerosis and arteriolosclerosis were underestimated, whereas acute tubular necrosis and interstitial fibrosis were overestimated, in the frozen sections compared to permanent ones, but those differences were not statistically significant. Immediate graft function was observed in 45 patients (61%). Delayed graft function was more frequently observed among recipients with donor age above 60 years (57% vs. 32%). Serum creatinine 3 months after transplantation was above 2 mg/dL in 33 recipients (44.5%) and was positively correlated to the degree of tubular necrosis (p = 0.04) and donor age (p = 0.03). Donor age was correlated to the degree of arteriolosclerosis (p < 0.01). CONCLUSIONS: Frozen section preimplantation biopsy gives reliable information for the situation of the graft that is related to the outcome of renal transplantation.

Cyclosporine induces endothelin-1 mRNA synthesis and nitric oxide production in human proximal tubular epithelial cell cultures.

BACKGROUND: Cyclosporine (CsA) is implicated in the development of chronic allograft nephropathy, which is related to reduced long-term allograft survival. The activation of tubular epithelial cells is involved in the renal scarring process via stimulation of factors such as endothelin-1 (ET-1) and nitric oxide (NO). The effect of CsA on the activation of tubular epithelial cells towards increased production of ET-1 and NO was investigated in this study. METHODS: Human tubular epithelial cells (HK-2) were cultured in the presence of CsA at different concentrations (125, 250, 500, and 1,000 ng/mL). ET-1 m-RNA and NO production were measured using RT-PCR and Griess method, respectively. The cytotoxic effect of CsA was examined by the MTT method and cell count. RESULTS: A statistically significant and dose-dependent cytotoxic effect of cyclosporine on HK-2 cells was observed. A dose-dependent up-regulation of ET-1 mRNA production and NO accumulation was observed under the influence of CsA. CONCLUSION: Increased synthesis of endothelin-1 mRNA and nitric oxide as well as a significant cytotoxic effect on tubular epithelial cells under the influence of CsA might be related to the development of CsA nephrotoxicity.

Corticosteroids vs. corticosteroids plus cycloporin A in adult minimal changes disease.

BACKGROUND: Adult minimal changes disease (MCD) is usually treated by high corticosteroids dose in order to achieve remission of nephrotic syndrome. In this study, the administration of high steroid dose (prednisolone 1 mg/kg BW/day) is compared with the combination of lower prednisolone dose (0.3 mg/kg BW/day) and cyclosporine A (CsA) (2-3 mg/kg BW/day) in a small number of patients. FINDINGS: Eighteen patients were allocated to either prednisolone monotherapy or prednisolone and CsA combination, according to the risk of developing steroid side-effects. Complete remission of the nephrotic syndrome was observed in all patients treated by steroids or combination of steroids and CsA. Complete remission occurred in 67%, 89% and 100% of patients after 4, 8 and 12 weeks of treatment. Relapses occurred in 50% of patients from both groups, treated with the combination of low prednisolone dose and CsA and followed by sustained remission. Corticosteroidal side effects were observed only in high prednisolone dose (accumulated dose: 92.7 +/- 22 mg/kg/BW vs. 58.5 +/- 21 mg/kg/BW, p = 0.004). CONCLUSION: Treatment of adult MCD with low prednisolone dose and CsA seems to be equally effective with high prednisolone dose to induce remission of nephrotic syndrome. It is also effective as maintenance therapy for prevention of relapses and less frequently followed by corticosteroidal side effects.

Early histological changes in the kidney of people with morbid obesity.

BACKGROUND: Morbid obesity represents a major health problem with increasing incidence worldwide. The clinical manifestation of renal involvement in obesity is proteinuria, and the histological feature is glomerulomegaly with or without focal and segmental glomerulosclerosis (FSGS). In this study, we have investigated the very early histological changes in kidneys of people with morbid obesity and no proteinuria. Patients and methods. Eighteen patients with body mass index (BMI) >50 kg/m(2) who underwent a variant of biliopancreatic diversion with Roux-en-Y reconstruction (BPD-RYGBP) and consented to undergo a renal biopsy during the surgical procedure were included in the study. The estimation of early histological changes was performed on light (n = 18) and electron microscopy (n = 13). RESULTS: The mean glomerular cross-sectional area was 30 943 +/- 10,984 microm(2) that is higher than that observed in non-obese individuals. In 21% of the examined glomeruli, the glomerular planar surface area (GPSA) was >40,000 microm(2). Thickening of the glomerular basement membrane (GBM) and scattered paramesangial deposits were identified in 9 of 13 patients (70%) whose renal tissue was examined by electron microscopy. A reduction in the slit pore frequency was observed in obese patients due to extensive foot process effacement. Significant positive correlations between mean GPSA and body weight (r = 0.462, P = 0.05), and between GBM thickness and HbA1c, serum total cholesterol and triglyceride levels (r = 0.60, P = 0.05; r = 0.789, P = 0.004; r = 0.70, P = 0.016, respectively), were observed. CONCLUSIONS: Glomerulomegaly as well as histological lesions resembling those of early diabetic nephropathy are observed in kidney biopsies of patients with morbid obesity even before the appearance of microalbuminuria. The potential regression of these changes after weight loss needs to be clarified.

Growth factors and apoptosis-related protein expression in human crescentic nephritis.

BACKGROUND: Crescentic nephritis is a renal disease that rapidly progresses toward renal failure unless aggressive immunosuppressive treatment is administered. Gene-directed apoptosis is involved in the resolution of renal injury or its progression toward scarring. In the present study, the expressions of growth factors, myofibroblasts [alpha-SMA(+) cells], and apoptosis-related proteins, were estimated to identify their contribution to the organization of crescents and to the clinical course of the disease. MATERIAL/METHODS: The extent of immunostaining for EGF, IGF-1, TGF-beta1, alpha-SMA(+) cells, as well as bax and bcl-2 proteins was estimated in cellular, fibrocellular, and fibrotic crescents of 17 kidney biopsy specimens from patients with crescentic nephritis, and correlated with the clinical course of the disease. RESULTS: Growth factors, apoptosis-related proteins, and myofibroblasts were identified within crescents, glomeruli, and tubulointerstitial area. EGF and bax protein were mainly identified in cellular crescents (>50%) whereas TGF-beta1, myofibroblasts, and bcl-2 protein were observed in fibrocellular crescents (>50%). The expression of all parameters was significantly reduced in fibrotic crescents. The presence of glomeruli with a ruptured Bowman capsule and an increased serum creatinine level at diagnosis were associated with an unfavorable clinical course with no response to immunosuppressive therapy (P<0.05 and P<0.02, respectively). CONCLUSIONS: Growth factors and the apoptotic process are involved in the organization of cellular to fibrotic crescents resulting in irreversible damage and an unfavorable clinical outcome. Identifying different patterns among growth factors and apoptosis-related proteins during the organization of crescents suggests an interplay between growth factors and the apoptotic process in the development of crescentic nephritis.

Calciphylaxis: a complication of end-stage renal disease improved by parathyroidectomy.

A 43-year old Caucasian male with end-stage renal disease presented with painful skin lesions and high calcium phosphate product that did not respond to medical treatment. Skin biopsy confirmed the diagnosis of calciphylaxis. Urgent parathyroidectomy was performed and resulted in decrease in the calcium phosphate product and improvement of his symptoms and signs.

Endothelin receptors in the kidney of patients with proteinuric and non-proteinuric nephropathies.

BACKGROUND: Endothelin-1 (ET-1), which acts via the specific receptors ET-A and ET-B, has been implicated in the development of renal scarring. The activation of the endothelin system was observed in experimental models of glomerular diseases and was attributed to the toxic action of proteinuria on the tubular epithelial cells. The aim of this study was to investigate whether the endothelin system in the kidney is altered in glomerular diseases and possibly related to proteinuria. METHODS: Thirty-seven patients with different types of glomerulonephritis and 14 controls were included. Patients presented either nephrotic syndrome (n=25) or mild proteinuria (<1g/24h, n=12). The expression of ET-A and ET-B receptors in the renal tissue was examined immunohistochemically. At the time of biopsy, urinary ET-1 was determined. RESULTS: Both receptors were mainly localized within tubular epithelial cells, and their expression was significantly higher in patients with glomerulonephritis compared to controls. The expression of ET-B was higher in nephrotic compared to non-nephrotic patients, while no difference was observed in the expression of ET-A receptors. A significant positive correlation of the degree of proteinuria with the excreted ET-1 (r= 0.487, p<0.05) and the extent of immunostaining for ET-B receptors (r=0.420, p<0.05) was observed. The expression of ET-B receptors and the excretion of ET-1 decreased significantly in patients with remission of nephrotic syndrome after therapy. CONCLUSION: This study provides evidence that the endothelin system is activated in human glomerular disease, confirming data from experimental studies. Proteinuria seems to be related to the activation of endothelin system, though further investigation is necessary to clarify this issue.

Cyclosporin-A in the treatment of nephrotic syndrome: the importance of monitoring C0 (trough) and C2 (two hours after its administration) blood levels.

Cyclosporin-A (CsA) is often used in the treatment of nephrotic syndrome. The effectiveness of CsA and the value of C2 blood levels in the treatment of nephrotic syndrome, due to various glomerular diseases, were studied. Forty-two nephrotic patients (M/F 21/21), with well-preserved renal function (creatinine clearance 87+/-20 ml/min) were included in the study. The original diagnoses were minimal change disease (MCD), focal segmental glomerulosclerosis (FSGS), membranous nephropathy (MN), IgA nephropathy (IgAN), and lupus nephritis (LN). All patients were treated with prednisolone and CsA for 24 months. Cyclosporin-A C0 and C2 blood levels were determined at regular intervals. Remission of the nephrotic syndrome was observed in all patients with MCD, IgAN and LN, in 75% with FSGS and in 83% with MN. Relapses were observed in some patients with MCD (25%) and MN (36%). The C0 levels were 93+/-15 ng/ml and the corresponding C2 levels were 498+/-110 ng/ml. However, significantly lower (340+/-83 ng/ml) or higher (680+/-127 ng/ml) to the average C2 levels were found in 6 patients (14%). No relation of C0 and C2 levels with the remission and relapse rate of the nephrotic syndrome and with renal function impairment was observed. Small doses of CsA with prednisolone are effective in the treatment of nephrotic syndrome. Although an individual variation of C2 was observed for the same target C0 levels, no relation of C2 levels was found with the remission or relapse rate of the nephrotic syndrome.

Immunosuppressive treatment of idiopathic focal segmental glomerulosclerosis: a five-year follow-up study.

BACKGROUND/AIMS: Focal segmental glomerulosclerosis (FSGS) is a common type of glomerular disease that can lead to chronic renal failure. Various therapeutic regimens have been used in nephrotic FSGS patients. The effect of treatment with prednisolone alone or its combination with azathioprine and cyclosporin and parameters related to a poor outcome are studied. METHODS: Fifty-one patients with idiopathic FSGS and a follow-up period of 5 years were included. Twenty-five were treated with prednisolone alone (1 mg/kg BW/day) or combination of prednisolone (0.5 mg/kg BW/day) with azathioprine (2 mg/kg BW/day) or cyclosporine (3 mg/kg BW/day) in gradually reduced doses whereas 26 patients received no immunosuppressive drugs. Lower prednisolone dose regimens were used as initial treatment in obese, borderline diabetics or patients with bone disease. The clinical course was estimated using the end-points of 50% or doubling of baseline serum creatinine and/or end-stage renal failure. The contribution of clinical and histological parameters in the clinical outcome was estimated by univariate and multivariate analyses. RESULTS: Increase of baseline serum creatinine by 50% during the follow-up period was observed in 2 treated and 9 untreated patients (8% vs. 35%, p = 0.03) whereas doubling of serum creatinine in 2 and 5 patients respectively (8% vs. 19%, p = NS). End-stage renal failure developed in 4 of 51 patients (8%), 2 treated and 2 untreated (p = NS). Parameters related to a poor outcome were baseline serum creatinine and severity of glomerulosclerosis (multivariate analysis OR = 1.08, p = 0.01). Most of patients (68%) who reached end-points had persistent nephrotic syndrome during the follow-up. Remission of nephrotic syndrome was observed more frequently among treated (75 vs. 30.7%, p = 0.05). Prednisolone alone was followed by remission of nephrotic syndrome in 62.5% whereas combination of lower prednisolone dose with azathioprine and cyclosporin in 80 and 85.7% of patients. No serious side-effects were observed. CONCLUSION: This and previous studies suggest that steroid and/or immunosuppressive therapy have a role in amelioration of the clinical course and remission of nephrotic syndrome in patients with FSGS A combination of low predisolone dose with cyclosporine could be used as initial treatment in patients with higher risk for side-effects from the usual prednisolone dose.

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.

Urinary transforming growth factor-beta1 excretion in renal allograft recipients during the early post-transplantation period.

BACKGROUND: Transforming growth factor-beta1 (TGF-beta1), the major fibrogenic growth factor, is implicated in the pathogenesis of renal scarring in experimental and clinical nephropathies as well as in chronic allograft nephropathy. In this study we examined the pattern of changes of TGF-beta1 excretion in the urine and the sites of TGF-beta1 expression in the kidney of transplanted patients during the early post-transplantation period. METHODS: Eighteen renal allograft recipients were included in the study. In all patients urinary TGF-beta1 levels were determined by ELISA in sequential measurements during the first two postoperative months and compared to that of 14 healthy subjects. The renal expression of TGF-beta1 protein was studied in 4 patients that underwent a biopsy of the transplanted kidney at the same period. All patients were treated with prednisolone, cyclosporin, and mycophenolate mofetil. RESULTS: Urinary TGF-beta1 levels were increased during the first postoperative days. Although they were gradually reduced during the first two post-operative months, they remained significantly higher compared to those of normal subjects (580 +/- 148 ng/24 h vs. 310 +/- 140 ng/ 24 h p < 0.01). The decline of urinary TGF-beta1 excretion followed that of serum creatinine. TGF-beta1 protein expression was identified within the cytoplasm of tubular epithelial cells of transplanted patients. CONCLUSIONS: Elevated urinary TGF-beta1 levels are observed during the early post-transplantation period in renal allograft recipients and are maintained high even after restoration of renal function to normal.

Prednisolone and azathioprine in IgA nephropathy - a ten-year follow-up study.

BACKGROUND: Immunoglobulin A nephropathy (IgAN) is one of the most common primary glomerular diseases. Although its clinical course is usually benign, some patients develop end-stage renal failure (ESRF). The role of immunosuppressive drugs in the treatment of IgAN remains controversial. The effect of treatment with prednisolone and azathioprine and the clinical and histological parameters related to a poor outcome are examined retrospectively in this analysis. METHODS: Seventy-four patients with IgAN and a follow-up period of 10 years were included in this study. Forty-one were treated with prednisolone (initially 60 mg/day) and azathioprine (initially 2 mg/kg BW/day) in gradually reduced doses for 24 +/- 9 months, whereas 33 patients received no immunosuppressive drugs. The clinical course was estimated using the end-points of doubling of baseline serum creatinine and/or ESRF. The contribution of clinical and histological parameters in the clinical outcome was estimated by univariate and multivariate analyses. RESULTS: The overall clinical courses of both groups of patients showed a rather similar pattern. Doubling of serum baseline creatinine was observed in 9 of 41 treated (22%) and in 10 of 33 untreated (30%), whereas ESRF developed in 6 treated (15%) and 6 untreated patients (18%) (p = NS). However, treated patients with heavy proteinuria (>3 g/24 h) had a significantly better outcome compared to untreated (doubling of serum creatinine in 29 vs. 78% and ESRF in 17 vs. 55%, p < 0.05). Proteinuria (p < 0.01), mean blood pressure (p < 0.02), baseline serum creatinine (p = 0.02) and severity of interstitial myofibroblast expression (p = 0.02) were identified as independent risk factors related to a poor outcome by multivariate analysis. Side effects of treatment were not uncommon and observed in 10 (24%) patients. CONCLUSION: Treatment with prednisolone and azathioprine is beneficial in ameliorating the clinical course of a subset of IgAN patients with heavy proteinuria or impaired renal function. Patients with advanced renal failure and severe chronic histological lesions should not be treated by this regimen as no benefit is expected and there is a risk of side effects.

Transforming growth factor-beta(1) in the kidney and urine of patients with glomerular disease and proteinuria.

BACKGROUND: Transforming growth factor-beta(1) (TGF-beta(1)) is the major fibrogenic growth factor implicated in the pathogenesis of renal scarring. Proteinuria is a poor prognostic feature for various types of glomerular disease and its toxic action may be related to the activation of tubular epithelial cells towards increased production of cytokines and chemoattractant peptides. In this work we studied the site of synthesis and expression profile of TGF-beta(1) in the renal tissue of patients with heavy proteinuria and examined the relation of this expression with the urinary excretion of TGF-beta(1). METHODS: Twenty-five patients with heavy proteinuria (8.4+/-3.0 g/24 h) were included in the study. All patients underwent a diagnostic kidney biopsy and were commenced on immunosuppressive therapy with corticosteroids and cyclosporin. The sites of synthesis and expression profile of TGF-beta(1) mRNA and protein in the kidney were examined by in situ hybridization and immunohistochemistry. Urinary and plasma TGF-beta(1) levels were determined by ELISA before the initiation of treatment and 6 months later and compared with those of normal subjects and of patients with IgA nephropathy and normal urinary protein excretion. RESULTS: The site of synthesis and expression of TGF-beta(1) in the renal tissue of patients with heavy proteinuria was mainly localized within the cytoplasm of tubular epithelial cells. Interstitial expression was also present but glomerular TGF-beta(1) expression was found only in patients with mesangial proliferation. Urinary TGF-beta(1) excretion was significantly higher in nephrotic patients compared with normal subjects and with patients with IgA nephropathy and normal urinary protein excretion (783+/-280 vs 310+/-140 and 375+/-90 ng/24 h, respectively; P<0.01). In patients with remission of proteinuria after immunosuppressive therapy, urinary TGF-beta(1) excretion was significantly reduced (from 749+/-290 to 495+/-130 ng/24 h; P<0.01), while in patients with persistent nephrotic syndrome, it remained elevated. CONCLUSIONS: The localization of TGF-beta(1) mRNA and protein within tubular epithelial cells, along with its increased urinary excretion in patients with nephrotic syndrome, suggest the activation of these cells by filtered protein towards increased TGF-beta(1) production.

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.