Management of idiopathic membranous nephropathy: evidence-based recommendations

Clinical efficacy and safety of different tacrolimus concentrations for the treatment of patients with idiopathic membranous nephropathy

This retrospective study aimed to explore the relative efficacy and safety of different tacrolimus (TAC) concentrations in the treatment of patients with idiopathic membranous nephropathy (IMN). A total of 260 IMN patients with nephrotic syndrome (NS) were recruited. Among these, 125 patients had TAC concentrations no greater than 5 ng/ml (C_TAC ≤ 5 ng/ml), and 135 patients had TAC concentrations greater than 5 ng/ml (C_TAC > 5 ng/ml). The primary outcomes included complete remission (CR) rates and overall (OR) response rates. The secondary outcomes included 24-h urinary protein (24-h UP), serum albumin and serum creatinine, and adverse events (AEs). During the 12-month follow-up, the overall response rates were significantly different between the C_TAC ≤ 5 ng/ml group and the C_TAC > 5 ng/ml group (P < 0.0001). However, there was no significant difference in the CR at 12 months between the two groups (chi-square, 62% vs 63%, P = 0.852). Compared with the C_TAC ≤ 5 ng/ml group, the C_TAC > 5 ng/ml group had improved levels of 24 h UP (P = 0.017) and serum albumin (P = 0.010). Moreover, the incidences of acute reversible nephrotoxicity (P < 0.001), hepatotoxicity (P = 0.036), new-onset diabetes mellitus (P = 0.036), and glucose intolerance (P = 0.005) were lower in the C_TAC ≤ 5 ng/ml group than in the C_TAC > 5 ng/ml group. The C_TAC > 5 ng/ml group was improved relative to the C_TAC ≤ 5 ng/ml group in terms of a PR and CR at 6 months, but there was no difference in the CR between the two groups at 12 months.

Tacrolimus versus cyclophosphamide for patients with idiopathic membranous nephropathy and treated with steroids: a systematic review and meta-analysis of randomized controlled trials

Background

The therapeutic effects of tacrolimus (TAC) versus cyclophosphamide (CTX) were not fully illustrated for patients with idiopathic membranous nephropathy (IMN).

Methods

The PubMed, EmBase, Cochrane library, and CNKI were systematically searched throughout March 2020 for randomized controlled trials evaluating the therapeutic effects of TAC versus CTX for IMN patients treated with steroids. The pooled relative risks (RRs) and weighted mean differences (WMDs) with 95% confidence intervals (CIs) were calculated using the random-effects model.

Results

Twelve trials recruited a total of 868 IMN patients were identified and contained in final meta-analysis. Patients in TAC group was associated with an increased incidence of overall remission (12 trials: 868 patients; RR: 1.21; 95% CI: 1.11–1.31; p < 0.001) and complete remission (12 trials: 868 patients; RR: 1.50; 95% CI: 1.25–1.80; p < 0.001). Moreover, we noted TAC therapy significantly reduced urinary protein excretion (9 trials: 567 patients; WMD: −1.06; 95%CI: −1.41 to −0.71; p < 0.001), and increased serum albumin (9 trials: 567 patients; WMD: 5.37; 95%CI: 2.97 to 7.77; p < 0.001) than CTX therapy. Furthermore, no significant difference between TAC and CTX for serum creatinine was detected (6 trials: 378 patients; WMD: 0.15; 95%CI: −3.46 to 3.75; p = 0.936). Finally, the risk of alopecia (p = 0.008), infection (p = 0.045), leukocytosis (p = 0.002), and elevated ALT/AST (p = 0.011) in TAC group was significantly lower than CTX group, whereas TAC was associated with an increased risk of tremor than CTX (p = 0.010).

Conclusions

This study found IMN patients treated with TAC combined with steroids provides a better therapeutic effect and less adverse events than those treated with CTX combined with steroids, with moderate-certainty evidence.

Early initiation of immunosuppressive treatment in membranous nephropathy patients

BACKGROUND/PURPOSE

Suggestion for the management of idiopathic membranous nephropathy (IMN) includes 6 months of observation, followed with steroid plus alkylating agent. However, delayed immunosuppression exposes the kidneys to persistent damage. This study aimed to examine the benefit of early immunosuppression in IMN patients.

METHODS

A retrospective study was performed. From 1993 to 2013, 161 IMN patients were enrolled. Patients receiving immunosuppression within 6 months after diagnosis were classified as initial-treatment group, whereas other patients as initial-no-treatment group. The clinical outcomes and complication were examined.

RESULT

Patients in the initial-treatment group had lower serum albumin concentration, less diabetes, and were younger. Steroid monotherapy is the main immunosuppression (64.5%) in this group. The initial-treatment group had a higher complete and partial remission rate than the initial-no-treatment group 6 months (52.9% vs. 35.0%, p=0.05) and 12 months (71.1% vs. 45.0%, p=0.003) after diagnosis. A similar result was seen between initial-steroid monotherapy and initial-no-treatment patients. Early immunosuppression is an independent predictor of remission within 1 year [hazard ratio (HR)=2.09; 95% confidence interval (CI)=1.25-3.49; p=0.005] and estimated glomerular filtration rate (eGFR) decline over 50% during the follow-up. (HR=0.33; 95% CI=0.13-0.86; p=0.02). The initial-treatment group also had a low frequency of eGFR decline over 50% (p=0.001) and low combined end-stage renal disease/mortality (p=0.001) compared with the initial-no-treatment group, but without more immunosuppression-related complication.

CONCLUSION

In contrast to Western countries, early immunosuppression (even steroid monotherapy) in our patients is associated with better remission in the 1^st year and renal preserve. Further randomized controlled trials are needed to clarify the benefit of early immunosuppression in IMN patients, especially with oriental ethnic background.

Adult Nephrotic Syndrome after Hematopoietic Stem Cell Transplantation: Renal Pathology is the Best Predictor of Response to Therapy

Nephrotic syndrome (NS) after allogeneic hematopoietic stem cell transplantation (HSCT) is a rare phenomenon usually associated with graft-versus-host disease (GVHD). This systematic review of post-HSCT NS cases reported in the literature aimed to identify risk factors and unique features of the disease in this clinical setting. One hundred sixteen cases of post-HSCT NS published in the English literature between 1988 and 2015 were revealed and analyzed. The median onset of NS was 20.5 months (range, 3 to 174) post-HSCT. NS development was associated with acute or chronic GVHD in 87.2% of cases. Membranous nephropathy (MGN) was the most frequent pathology (65.5%), followed by minimal change disease (MCD) (19%). Complete remission of the NS was achieved in 63.5% of patients (59.1% of MGN cases and 81.3% of MCD cases; P = .15). Patients presenting with MCD recovered at a median of 1.75 months (range, 1 to 12) and with MGN a median of 7 months (range, 1 to 53) (P = .001). NS was treated with corticosteroids alone in 16.8% of patients and with a combination of corticosteroids and other immunosuppressive agents in 73.5% of patients. Univariate analysis failed to identify a single predictive factor of response to therapy. In conclusion, post-HSCT NS usually develops concomitant to GVHD and is associated with high rates of response to therapy. Although most patients were treated with a combination of immunosuppressive drugs, single-agent therapy with steroids may be sufficient in some cases.

Fasting plasma glucose levels predict steroid-induced abnormal glucose metabolism in patients with non-diabetic chronic kidney disease: a prospective cohort study

BACKGROUND/AIMS

Glucocorticoids-induced abnormal glucose metabolism (AGM) is a common medical problem in patients with non-diabetic chronic kidney disease (CKD). However, little information is available regarding the prediction of steroid-induced AGM in this patient population.

METHODS

In this prospective cohort study, we consecutively enrolled 303 non-diabetic CKD patients with fasting plasma glucose (FPG) levels <5.6 mmol/l and normal oral glucose tolerance test (OGTT). OGTT was performed every 3 months during glucocorticoid treatment to identify new-onset AGM, and patients were followed for 12 months post steroid withdrawal.

RESULTS

During 593 person-years, there were 107 incident cases of steroid-induced AGM (18/100 person-year), including 55 (51.4%) diabetes and 52 (48.6%) pre-diabetes. In a multivariate model, each millimole increase per liter in FPG enhanced the risk of AGM by 4.6-fold (hazard ratio 4.58, 95% confidence interval, 2.67-7.83). After adjusting other risk factors, a progressively increased risk of AGM or DM was observed in patients with FPG levels ≥4.8 mmol/l, as compared with those whose levels were ≤4.3 mmol/l (p for trend <0.001). Furthermore, a greater increase in FPG level (≥0.3 mmol/l) during the first 3 months of glucocorticoid treatment was associated with an increased risk for future diabetes. For predicting steroid-induced diabetes, the area under the receiver-operating characteristic curve was 0.90 for the combination of FPG and changes in FPG levels at month 3.

CONCLUSION

Higher-normal FPG and a greater increase in FPG levels during glucocorticoid treatment may help to identify non-diabetic CKD patients at increased risk of steroid-induced AGM or diabetes.

Stepwise treatment using corticosteroids alone and in combination with cyclosporine in korean patients with idiopathic membranous nephropathy

PURPOSE

We undertook an observational study to investigate the effects of immunosuppressive treatment on proteinuria and renal function in 179 Korean idiopathic membranous nephropathy patients with nephrotic syndrome.

MATERIALS AND METHODS

The primary outcome was regarded as the first appearance of remission and the secondary outcomes as a decline in estimated glomerular filtration rate (eGFR) >50% or initiation of dialysis, and all-cause mortality. Seventy-two (40.2%) and 50 (27.9%) patients were treated with corticosteroids alone (C) and corticosteroids plus cyclosporine (C+C), respectively, whereas 57 (31.8%) did not receive immunosuppressants (NTx). Cyclosporine was added if there was no reduction in proteinuria of >50% from baseline by corticosteroids alone within 3 months.

RESULTS

There were no differences in baseline renal function and the amount of proteinuria among the three groups. Overall, complete remission (CR) was achieved in 88 (72.1%) patients by immunosuppressants. In a multivariate analysis adjusted for covariates associated with adverse renal outcome, the probability of reaching CR was significantly higher in the C [hazard ratio (HR), 4.09; p<0.001] and C+C groups (HR, 2.57; p=0.003) than in the NTx group. Kaplan-Meier analysis revealed that 5-year CR rates of C, C+C, and NTx groups were 88.5%, 86.2%, and 56.7% (p<0.001). Ten-year event-free rates for the secondary endpoints in these three groups were 91.7%, 79.9%, and 57.2% (p=0.01).

CONCLUSION

Immunosuppressive treatment was effective in inducing remission and preserving renal function in these patients. Therefore, stepwise treatment using corticosteroids alone and in combination with cyclosporine is warranted in these patients.

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.

Application of artificial neural networks in estimating predictive factors and therapeutic efficacy in idiopathic membranous nephropathy

Idiopathic membranous nephropathy (IMN) is one of the most frequent causes of the nephrotic syndrome in adults and one of the most common cause of chronic renal failure among primary glomerular diseases. The aim of this study was to develop artificial neural networks (ANN) to investigate factors of poor outcome for IMN and to evaluate the efficacy of different therapeutic protocols. Data were collected retrospectively for 124 patients with IMN (82 males, mean based on the received therapy patients were divided into three groups: corticosteroids only (group 1), cyclophsophamide with corticosteroids (group 2), and so called Ponticelli protocol (group 3). After achieving satisfactory truthfulness of the transcription function of ANN through clustering, we have applied the efficacy analysis to all patients and then compared them to each group separately, and evaluated the influence of initial characteristics on disease outcome as well as the therapy efficacy. The greatest therapy inefficiency was recorded for isolated corticosteroid therapy (29.41%) and the smallest inefficiency for Ponticelli protocol, for which the greatest accuracy of prognosis was recorded (82.09%). The greatest negative prognostic influence had kidney insufficiency (22%), quantitative proteinuria (15%) and index of interstitial infiltration (14%). Based on our results, we can recommend that patients diagnosed with IMN with renal insufficiency, nephrotic syndrome or a high degree of interstitial infiltration at the time of diagnosis should be treated concomitantly with cytotoxic drugs and corticosteroids, particularly with the Ponticelli protocol.

Coexistence of immune thrombocytopenic purpura and idiopathic membranous glomerulonephritis successfully treated with rituximab

We describe here coexistence of immune thrombocytopenic purpura (ITP) and idiopathic membranous glomerularnephritis (IMG) in one individual who presented a decade ago after delivering a macerated dead fetus. Investigations performed then revealed clinical, biochemical and histopathological evidence of IMG. A year later she presented with bleeding diathesis and was diagnosed as ITP. Thereafter, she manifested with several episodes of serious bleeding complications especially in the central nervous system with considerable frequency, inspite of receiving treatment with steroids, intravenous immunoglobulin and cyclosporine. Subsequently, she received six courses of rituximab and went into complete remission. To date, after more than 3.5 years of follow up, she is completely symptom free. Co-existence of IMG and ITP has been reported earlier; however, this is the first instance of successful treatment of both these entities with rituximab.

Tacrolimus in the treatment of idiopathic nephrotic syndrome

The immunosuppressant tacrolimus (FK-506) is a calcineurin inhibitor with a widespread use for the prevention of graft rejection in transplantation medicine. Tacrolimus inhibits the activation of an essential transcription factor for the transcription of cytokine genes in T cells leading to a decreased production of cytokines such as IL-2 and IFN-gamma. As T-cell activation plays a crucial role in the pathogenesis of inflammatory glomerular diseases, there is an increasing number of reports on the use of tacrolimus in nephrotic syndrome. In idiopathic nephrotic syndrome, corticosteroid treatment constitutes the first-line therapy to achieve remission. In the case of steroid resistance or steroid dependence, alternative immunosuppressive strategies are needed. Cyclophosphamide and ciclosporin are well-established drugs in this condition. The present article reviews the pharmacodynamics, pharmacokinetics, safety and clinical efficacy of tacrolimus in steroid-resistant and steroid-dependent nephrotic syndrome.

Corticosteroids and ciclosporin A in idiopathic membranous nephropathy: higher remission rates of nephrotic syndrome and less adverse reactions than after traditional treatment with cytotoxic drugs

BACKGROUND/AIM

Idiopathic membranous nephropathy, the most common cause of nephrotic syndrome in adults, has been traditionally treated with corticosteroids and cytotoxic drugs. Ciclosporin A (CsA) is used in resistant cases, but also as a first-line treatment, due to the serious side effects of cytotoxic drugs. In this study, the remission rates of nephrotic syndrome and the incidence of side effects of corticosteroids and low CsA doses are compared with those after treatment with cytotoxic drugs.

METHODS

Seventy-seven nephrotic patients with well-preserved renal function who were treated with methylprednisolone and CsA (n = 46) or cytotoxic drugs (n = 31) were studied. The effects of treatments were estimated on the basis of remission rates of nephrotic syndrome and preservation of the renal function.

RESULTS

Remission (complete or partial) of nephrotic syndrome was observed in 85% of the patients treated with CsA and in 55% of the patients treated with cytotoxic drugs (p < 0.01). Deterioration of the renal function, more common in patients with multiple relapses and interstitial fibrosis, was observed in 26 and 23% of the patients, respectively (p = NS). Serious side effects and discontinuation of treatment were more frequent in patients treated with cytotoxic drugs (10 vs. 4%).

CONCLUSION

The combination of corticosteroids with CsA represents a better regimen for patients having idiopathic membranous nephropathy, since it is associated with higher remission rates of nephrotic syndrome and less severe side effects than corticosteroids and cytotoxic drugs.

Glomerulonephritis

The term glomerulonephritis encompasses a range of immune-mediated disorders that cause inflammation within the glomerulus and other compartments of the kidney. Studies with animal models have shown the crucial interaction between bone-marrow-derived inflammatory cells and cells intrinsic to the kidney that is both fundamental and unique to the pathogenesis of glomerulonephritis. The mechanisms of interaction between these cells and the mediators of their coordinated response to inflammation are being elucidated. Despite these pathophysiological advances, treatments for glomerulonephritis remain non-specific, hazardous, and only partly successful. Glomerulonephritis therefore remains a common cause of end-stage kidney failure worldwide. Molecule-specific approaches offer hope for more effective and safer treatments in the future.

Idiopathic membranous nephropathy: Definition and relevance of a partial remission

BACKGROUND

Membranous nephropathy (MGN) remains the most common cause of adult onset nephrotic syndrome, and within the primary glomerulonephritis group is a leading cause of renal failure. A complete remission (CR) confers an excellent long-term prognosis, but the quantitative benefits of partial remissions (PR) have not been defined.

METHODS

This study evaluated the rate of renal function decline (slope), relapse, and renal survival in nephrotic MGN patients with CR, PR, or no remission (NR). Multivariate analysis included clinical and laboratory data at presentation and over follow-up, blood pressure control and agents employed, and immunosuppressive therapy.

RESULTS

The study cohort consisted of 348 nephrotic MGN patients with a minimum of 12 months follow-up identified from the Toronto Glomerulonephritis Registry. Over a median follow-up of 60 months, 102 experienced a CR, 136 had a PR, and 110 had no remission. A PR was independently predictive of slope and survival from renal failure by multivariate analysis (hazard ratio 0.08, 95% CI 0.03-0.19, P < 0.001). Benefit from immunosuppression could only be shown in a subset of high-risk patients. Treatment-related PR had the same long-term implication as spontaneous ones. Relapses from PR were high (47%) but often reversible.

CONCLUSION

A partial remission is an important therapeutic target with implications for both progression rate and renal survival.

Prognosis and risk factors for idiopathic membranous nephropathy with nephrotic syndrome in Japan

BACKGROUND

Idiopathic membranous nephropathy (IMN) is a representative form of refractory nephrotic syndrome in Japan. Although IMN is thought to run a more benign course in Japanese than in the Caucasian population, risk factors and appropriate treatment are controversial issues.

METHODS

The research group supported by a grant for "Progressive Renal Disease" from the Ministry of Health, Labor and Welfare, Japan, carried out a national survey of patients with IMN and nephrotic syndrome. Of 1066 nephrotic patients with histopathologically proven IMN registered from 1975 to 1993 in 85 institutions, 949 patients were studied.

RESULTS

The overall renal survival rates were 95.8%, 90.3%, 81.1%, and 60.5% at 5, 10, 15, and 20 years after diagnosis, respectively. When clinical and histopathologic features at onset of nephrotic syndrome were evaluated by multivariate analysis, male gender, old age (> or =60 years), high serum creatinine concentration (> or =1.5 mg/dL), and the development of tubulointerstitial lesions (> or =20% of the biopsy sample area) were significant predictors of progression to end-stage renal disease (ESRD). The renal survival rate in patients on steroid therapy was significantly higher than in patients on supportive therapy alone. Patients achieving a remission showed a significant reduction of risk for progression.

CONCLUSION

IMN is a disease with a comparatively good prognosis in Japan even when it is associated with nephrotic syndrome. Steroid therapy, which has not been recommended for IMN in most review articles, seems to be useful at least for Japanese patients. In particular, a remission from heavy proteinuria likely results in a favorable outcome.

Nephrotic syndrome caused by membranous nephropathy: response to a short course of cyclophosphamide alternating with prednisolone

OBJECTIVE

The optimal duration of immunosuppressive therapy and the timing of treatment for treating membranous nephropathy (MN) have yet to be established. We examined outcomes of a short course of cyclophosphamide alternating with prednisolone for MN patients with nephrotic syndrome.

METHODS AND PATIENTS

Cyclophosphamide (2 mg/kg/day for 8 weeks) combined with prednisolone (1 mg/kg every 48 hours for 8 weeks, then tapering off for 1 year) was prescribed for 28 MN patients (12 men and 16 women; mean age 52.4+/-2.25 years SEM). We first evaluated the response rates to this combined therapy, then compared the clinical characteristics of those who achieved remission (group A) with those who did not (group B) within 6 months of the start of treatment.

RESULTS

The incidences of complete and partial remission increased with the follow-up period; 32 and 21% by 6 months, 54 and 29% by 12 months, and 79 and 11% by 24 months, respectively. Serum IgG (906+/-100.8 versus 562+/-66.1 mg/day; p<0.01) was significantly higher in group A, and the selectivity index (C(IgG)/C(albumin) 0.16+/-0.015 versus 0.30+/-0.040; p<0.01), significantly lower. Nephrotic syndrome persisted in 3 group B patients (23%), who finally had impaired renal function.

CONCLUSION

MN patients with nephrotic syndrome responded favorably to a short course of cyclophosphamide combined with prednisolone. The serum IgG level and selectivity index may serve as markers of early response to this treatment.

Conservative versus immunosuppressive treatment of patients with idiopathic membranous nephropathy

BACKGROUND

Treatment of idiopathic membranous glomerulonephritis (MGN) is a controversial issue. Whereas some authors recommend early immunosuppressive treatment of all patients with nephrotic syndrome, others do not support aggressive therapies, based on the spontaneous long-term favorable outcome of most patients. However, 20 to 50% of untreated patients develop progressive renal insufficiency.

METHODS

All of the patients with biopsy-proven MGN who developed renal insufficiency at our Hospital during the period of 1975 to 2000 were studied. Selected patients (N=39) were separated into two groups according to the two different therapeutic policies followed at our department: a conservative approach during the first period, 1975 to 1989 (group I, N=20), and a course of immunosuppressive therapy (oral prednisone for six months and concurrent oral chlorambucil, 0.15 mg/kg/day, during the first 14 weeks) during the second period, 1990 to 2000 (group II, N=19).

RESULTS

There were no significant differences between both groups at the time of renal biopsy, nor at the onset of renal function decline. All group I patients showed a progressive renal insufficiency; at the end of the follow-up 13 patients (65%) were on chronic dialysis, 2 (10%) showed advanced renal failure, and 5 (25%) had died. In contrast, most of group II patients showed an improvement or stabilization of serum creatinine (SCr; 2.3 +/- 0.9 mg/dL at onset of treatment, 2 +/- 1.5 mg/dL at the end of follow-up) together with decreased proteinuria (11.2 +/- 3.3 vs. 5.2 +/- 6.7 g/24 h). At the end of the follow-up 58% of group II patients had a SCr value < or =1.5 mg/dL and 36% showed a complete or partial remission, whereas no patient in group I showed remission. After four years of follow-up the probability of renal survival without dialysis was 55% in group I and 90% in group II (P < 0.001), and after seven years the renal survival was 20% and 90%, respectively (P < 0.001). Side effects of immunosuppressive treatment were uncommon but severe, as two patients suffered Pneumocystis carinii pneumonia.

CONCLUSION

A course of immunosuppressive treatment administered early at the onset of renal function decline induces a favorable effect in most of patients with MGN and deteriorating renal function. Untreated patients progressed without exception toward advanced renal failure.

Reactive oxygen species alter gene expression in podocytes: induction of granulocyte macrophage-colony-stimulating factor

It has been suggested that reactive oxygen radicals (ROS) play a crucial role in the pathogenesis of proteinuria and podocyte injury. It was investigated whether changes in gene expression might account for ROS-induced podocyte dysfunction. Differentiated podocytes were incubated with control media or with exogenous ROS from the xanthine/xanthine-oxidase reaction for 4 h. A PCR-based suppressive subtractive hybridization assay was applied to isolate and clone mRNAs that were differentially expressed by exogenous ROS. One differentially expressed clone was identified as the proinflammatory cytokine granulocyte macrophage-colony-stimulating factor (GM-CSF). Regulation of GM-CSF in podocytes was further studied by Northern analysis and enzyme-linked immunosorbent assay. Exogenous ROS caused a concentration-dependent, >10-fold induction of GM-CSF mRNA after 4 h. A >50-fold increase in GM-CSF protein release in podocytes that had been stimulated with ROS could be detected. Induction of GM-CSF protein was inhibited by actinomycin D, which indicated that increased mRNA transcription was involved. The ROS scavengers dimethyl-thio-urea and pyrrolidone-dithio-carbamate strongly inhibited increased GM-CSF production induced by ROS. GM-CSF release was also induced when internal ROS production was triggered with NADH, whereas H2O2 had only a small effect. GM-CSF release by podocytes was also stimulated by lipopolysaccharide (LPS), interleukin-1 (IL-1), and phorbolester (PMA). Dimethyl-thio-urea significantly inhibited the LPS-, IL-1-, and PMA-induced GM-CSF production. Activation of the transcription factor nuclear factor-kappaB (NF-kappaB) but not activator protein-1 was involved in the upregulation of ROS-induced GM-CSF production. The data indicate that GM-CSF is differentially expressed by ROS in podocytes. ROS also partially mediate the effects of PMA and IL-1 on podocyte GM-CSF production. Because GM-CSF can enhance glomerular inflammation and induces mesangial proliferation, these data might provide further insight into the mechanisms of ROS-induced glomerular injury.

Membranous glomerulopathy: emphasis on secondary forms and disease variants

Membranous glomerulopathy (MGN) is characterized by subepithelial immune complex deposits and glomerular basement membrane (GBM) thickening. The majority of patients present with nephrotic syndrome and outcomes are variable. Pathologically, deposits at sites other than the subepithelial aspect of the GBM favor the presence of secondary forms of MGN which are seen most commonly in the setting of autoimmune disease, infection, neoplasia, and with certain therapeutic agents. MGN is the most common form of de novo glomerular disease seen in the renal allograft and may be seen concurrently with other forms of glomerular disease including focal segmental glomerulosclerosis, IgA nephropathy, diabetic nephropathy, and anti-TBM nephritis. This review emphasizes the detection of secondary forms and variants of MGN.