Diosgenin protects against cationic bovine serum albumin-induced membranous glomerulonephritis by attenuating oxidative stress and renal inflammation via the NF-κB pathway

CONTEXT

Membranous glomerulonephritis (MGN) is a leading cause of nephrotic syndrome in adults. Diosgenin (DG) has been reported to exert antioxidative and anti-inflammatory effects.

OBJECTIVE

To investigate the renoprotective activity of DG in a cationic bovine serum albumin-induced rat model of MGN.

MATERIALS AND METHODS

Fourty male Sprague-Dawley rats were randomized into four groups. The MGN model was established and treated with a DG dose (10 mg/kg) and a positive control (TPCA1, 10 mg/kg), while normal control and MGN groups received distilled water by gavage for four consecutive weeks. At the end of the experiment, 24 h urinary protein, biochemical indices, oxidation and antioxidant levels, inflammatory parameters, histopathological examination, immunohistochemistry and immunoblotting were evaluated.

RESULTS

DG significantly ameliorated kidney dysfunction by decreasing urinary protein (0.56-fold), serum creatinine (SCr) (0.78-fold), BUN (0.71-fold), TC (0.66-fold) and TG (0.73-fold) levels, and increasing ALB (1.44-fold). DG also reduced MDA (0.82-fold) and NO (0.83-fold) levels while increasing the activity of SOD (1.56-fold), CAT (1.25-fold), glutathione peroxidase (GPx) (1.55-fold) and GSH (1.81-fold). Furthermore, DG reduced Keap1 (0.76-fold) expression, Nrf2 nuclear translocation (0.79-fold), and induced NQO1 (1.25-fold) and HO-1 (1.46-fold) expression. Additionally, DG decreased IL-2 (0.55-fold), TNF-α (0.80-fold) and IL-6 (0.75-fold) levels, and reduced protein expression of NF-κB p65 (0.80-fold), IKKβ (0.93-fold), p-IKKβ (0.89-fold), ICAM-1 (0.88-fold), VCAM-1 (0.91-fold), MCP-1 (0.88-fold) and E-selectin (0.87-fold), and also inhibited the nuclear translocation of NF-κB p65 (0.64-fold).

DISCUSSION AND CONCLUSIONS

The results suggest a potential therapeutic benefit of DG against MGN due to the inhibition of the NF-κB pathway, supporting the need for further clinical trials.

Membranous lupus nephritis secondary to secukinumab therapy: A case report and literature review

The interleukin (IL)-17 axis is involved in many inflammatory and autoimmune diseases. Secukinumab, an IL-17 inhibitor, has been approved for psoriasis treatment. There are accumulating cases of lupus erythematosus induced by IL-17 inhibition. Lupus nephritis after IL-17 inhibition has not been reported. We report the case of a 57-year-old man who developed membranous lupus nephritis after secukinumab treatment for psoriasis. Anti-SSA and PM-Scl antibodies were positive. dsDNA, anti-Smith, and anti-histone antibodies were negative, and serum complement was low. Secukinumab was discontinued, while tacrolimus was initiated, subsequently switched to cyclosporin, belimumab, glucocorticosteroid, and hydroxychloroquine with a good response. The relationship between lupus erythematosus and IL-17 inhibition requires further research.

An Unusual Case of Anti-Glomerular Basement Membrane Disease and Phospholipase A2 Receptor-Associated Membranous Nephropathy After Exposure to Hydrocarbons

We present a rare case of a patient with toluene exposure manifesting as anti-glomerular basement membrane (GBM) disease on a background of phospholipase A2 receptor (PLA2R)-associated membranous nephropathy. A 23-year-old man presented to the emergency department with hypertension, headache, hemoptysis, anemia, acute kidney injury, glomerular hematuria, and proteinuria. He endorsed repeated exposure to toluene-containing products while repairing dirt bikes. Serologies were positive for anti-GBM antibodies. Kidney biopsy showed crescentic glomerulonephritis with linear immunoglobulin G and granular PLA2R staining by immunofluorescence. He was initially treated with high-dose steroids, plasmapheresis, and hemodialysis for pulmonary-renal syndrome followed by oral cyclophosphamide and prednisone, which were discontinued after 3 months when follow-up biopsies confirmed little chance for renal recovery. He remained on dialysis 1 year later. This case exhibits a unique presentation of anti-GBM syndrome and underlying membranous nephropathy following repeated hydrocarbon exposure. Inhaled toxins promote recurrent localized inflammation, unmasking previously hidden epitopes. Early diagnosis and appropriate use of immunosuppressive and extracorporeal therapies are necessary to prevent morbidity and to improve survival in this rare condition.

Efficacy and Adverse Reactions of Mycophenolate Mofetil Combined with Hormone in the Treatment of Idiopathic Membranous Nephropathy: A Meta-Analysis

Background

The detection and prevalence of idiopathic membranous nephropathy in China are increasing yearly. However, the current treatment of idiopathic membranous nephropathy relies on empirical treatment regimens such as hormones and immunosuppressants, with unclear prognosis and easy recurrence.

Methods

Eight databases were searched to obtain controlled trials on the effects of mycophenolate mofetil combined with hormones in the treatment of idiopathic membranous nephropathy. After literature quality evaluation, data analysis was performed using RevMan 5.3 software.

Results

12 studies were ultimately included in this meta-analysis. 12 studies reported that, compared with the control group, the effective rate (OR: 1.15; 95% CI: 1.06, 1.26; P < .001), 24hUP (SMD:-0.35; 95% CI: -0.47, -0.23; P < .001), Alb (SMD: 1.92; 95% CI: -0.51, 4.36; P = .122), Scr (SMD: 4.44; 95% CI: -10.26, 1.38; P = .135), TG (SMD: 0.51; 95% CI: 0.88, 0.15; P < .01) and adverse events (OR: 0.86; 95% CI: 0.67,1.11; P = .255) of the test group was significantly higher.

Conclusion

The results of this study suggested that mycophenolate mofetil combined with hormone may be effective on patients with idiopathic membranous nephropathy, as evidenced by effective rate, 24hUP, Alb, Scr, TG, adverse events, and the above conclusions need to be verified by more high-quality studies.

Clinicopathological features and long-term prognosis of glomerular diseases associated with mercury-containing cosmetics

OBJECTIVE

The pathological types and long-term prognosis of glomerular diseases related to mercury exposure are unclear. This study retrospectively examined 41 cases of glomerulonephropathy caused by mercury-containing cosmetics.

METHODOLOGY

Forty-one subjects with glomerular diseases presumably caused by mercury-containing cosmetics were selected. Clinical features, kidney biopsy, treatment, and follow-up data were collected.

RESULTS

All patients were female with an average age of 39.4 ± 6.6 years at diagnosis. Median time of exposure to mercury-containing cosmetics was six months, and average urine mercury level was 66.80 ± 38.55ug/(g·Cr). Most patients presented with nephrotic syndrome. Renal histopathology showed membranous nephropathy in 22 patients (53.65%), minimal change disease in 13 patients (31.71%), IgA nephropathy with minimal change disease in 5 patients (12.20%), and focal segmental glomerulosclerosis in 1 patient. Median time of exposure to mercury was longer and the proportion of patients with autoantibodies (mainly antinuclear antibodies) was higher in patients with membranous nephropathy. Both blood phospholipase A2 receptor -Ab and kidney tissue phospholipase A2 receptor were negative. Thirty-six patients received glucocorticosteroids and/or immunosuppressants. Five patients were treated with an angiotensin receptor blocker, and nine patients were treated with chelation therapy. The median follow-up time was 40 months (range 27-94). All patients achieved complete remission, and the median time to complete remission was one month. They all successfully discontinued the drugs without relapsing; withdrawal time was 26 months.

CONCLUSION

Membranous nephropathy was the most common pathological type in mercury-induced glomerular disease. Patients were sensitive to glucocorticosteroids and immunosuppressants and achieved complete remission quickly. Contrary to primary glomerulonephritides, patients with mercury-induced glomerular diseases had no relapses after withdrawal of the mercury containing cosmetics.

Mercury-associated neural epidermal growth factor-like 1 protein (NELL-1) positive membranous nephropathy after use of skin lightening creams

INTRODUCTION

Membranous nephropathy, one of the common causes of glomerulonephritis worldwide, is reported in association with mercury exposure. Neural epidermal growth factor-like 1 protein is a recently described target antigen in membranous nephropathy.

CASE SERIES

Three woman (ages 17, 39, and 19 years old) presented sequentially for our evaluation with complaints consistent with nephrotic syndrome. All three had nephrotic range proteinuria, hypoalbuminemia, hypercholesterolemia, hypothyroidism, and inactive urinary sediments. Kidney biopsies were performed in the first two patients, which demonstrated findings consistent with membranous nephropathy and positive staining for neural epidermal growth factor-like 1 protein. On discovery that they were all using the same skin-lightening cream, samples of the cream were tested and found to contain between 2,180 parts per million and 7,698 parts per million of mercury. Elevated urine and blood mercury concentrations were also found in the first two patients. All three patients improved following cessation of use and treatment with levothyroxine (all three patients) and corticosteroids and cyclophosphamide in patients one and two.

DISCUSSION

We hypothesize the role of autoimmunity triggered by mercury exposure in the pathogenesis of neural epidermal growth factor-like 1 protein membranous nephropathy.

CONCLUSION

Mercury exposure should be carefully assessed as a part of the evaluation of patients with neural epidermal growth factor-like 1 protein positive membranous nephropathy.

Investigation of pharmacologic interactions between omeprazole and tacrolimus in a membranous nephropathy patient with CYP3A5 nonexpresser: a case report

Tacrolimus has been widely used in membranous nephropathy in recent years. The drug interactions of the coadministration of tacrolimus with omeprazole in CYP3A5 nonexpresser membranous nephropathy patients have not been demonstrated. Here, we report an idiopathic membranous nephropathy patient who was with CYP2C19*2/*2, CYP3A5*3/*3 (nonexpresser) and ABCB1 (3435 TT, 1236 computed tomography, 2677 TT) genotype requiring treatment with tacrolimus and omeprazole and found to have fluctuating metabolism of tacrolimus. This study shows that tacrolimus and omeprazole have pharmacologic drug interactions in CYP3A5 nonexpressers, implying that the CYP3A and ABCB1 gene mutations linked to tacrolimus metabolism may alter tacrolimus levels in the blood. The observed concentrations of tacrolimus were decreased after the discontinuation of omeprazole therapy. It demonstrates that, in addition to genotype, clinical covariates, such as omeprazole are important when it comes to better understanding and prediction of tacrolimus dosage. It is deemed necessary to monitor tacrolimus blood concentrations and make dose adjustments when patients were coadministered with omeprazole.

Case Report: Successful treatment of late-onset immune checkpoint inhibitor-associated membranous nephropathy in a patient with advanced renal cell carcinoma

Background

Diagnosing immune checkpoint inhibitor (ICI)-associated nephritis can be challenging since it is a rare complication of therapy, associated with a spectrum of immune-mediated pathologies, and can present months after ICI therapy discontinuation (i.e., late-onset). ICIs are increasingly administered in combination with other cancer therapies with associated nephrotoxicity, further obfuscating the diagnosis of ICI-associated nephritis. In this report, we describe the first suspected case of late-onset ICI-associated membranous nephropathy (MN) in a patient with metastatic clear cell renal cell carcinoma (RCC) who had discontinued ICI therapy 6 months prior to presentation. Prompt recognition of the suspected late-onset immune-related adverse event (irAE) resulted in the successful treatment of MN and continuation of RCC therapy.

Case presentation

A 57-year-old man with metastatic clear cell RCC was responsive to third-line RCC therapy with lenvatinib (oral TKI) and everolimus (oral mTOR inhibitor) when he presented with nephrotic range proteinuria and acute kidney injury (AKI). His kidney biopsy revealed probable secondary MN with subendothelial and mesangial immune complex deposits and negative staining for both phospholipase A2 receptor (PLA2R) and thrombospondin type-1 domain-containing 7A (THSD7A). While a diagnosis of paraneoplastic MN could not be excluded, the patient was responding to cancer therapy and had tumor regression. However, 6 months prior to presentation, the patient had received pembrolizumab, an ICI, with his first-line RCC treatment. Due to concern that the patient may be presenting with late-onset ICI-associated MN, he was effectively treated with rituximab, which allowed for his continued RCC therapy.

Conclusion

This report highlights the first case of suspected late-onset ICI-associated MN and the increasing complexity of recognizing renal irAEs. With the growing indications for the use of ICIs in combination with other cancer therapies, recognizing the various presentations of ICI-immune nephritis can help guide patient management and treatment.

Role of Rituximab in Patients with Resistant Nephrotic Syndrome

Resistant nephrotic syndrome is a group of disorders with diverse histological findings, which are by definition resistant to corticosteroids given in adequate dose for adequate duration and many are resistant to other therapy as well. In many patients progression to end-stage renal disease is the ultimate outcome. The role of B cells has not been fully explained in man, agents that specifically interfere with B cells would ideally represent the first step toward selective therapy. We studied short term and long term effects of rituximab in patients with resistent primary nephrotic syndrome.

MATERIAL

Study was conducted at SMS-medical college and Hospital Jaipur, four doses of rituximab were given weakly, in fixed dose of 500 mg per dose and proteinuria was evaluated before start of therapy and at 3 months, 6 months and 12 months of therapy. Patients with resistant primary nephrotic syndrome who failed to respond to other therapies, with stable eGFR &gt;30, and controlled BP were included in study. Patients with Active infection, Uncontrolled hypertension, pregnancy were excluded from study.

OBSERVATION

10 patients were enrolled in study out of which 7 FSGS (focal segmental glomeruloscllerosis) and 3 were IMN (idiopathic membranous nephropathy), 5 were female and 5 were male, age 17-61years (average 34.6), weight were 48-70 kg (avg 57.9), BMI 19.4-23 (AVG 21.18), all patients have normal renal function (average creatinine value of 0.8, range= 0.5 to 1.1). At 3 months 1 patient had partial response and 9 had no response. At 6 months of treatment 2 patients had partial response, 3 had complete response and 5 no response. At 12 months of treatment 4 had partial response, 5 had complete response and 1 no response. Out of 10 patients no one had relapse of Nephrotic syndrome at 12 month of therapy. Renal function remain normal in all patients over 12 months followup.

CONCLUSION

This prospective, observational study evaluated 3 month, 6 month, and 12 month outcome of 3 IMN and 7 FSGS patients, with persistent nephrotic range proteinuria and showed that rituximab promoted sustained remission in proteinuria in resistent nephrotic syndrome with normal renal function.

Clinical Outcome of Idiopathic Membranous Nephropathy-A Single Centre Study

INTRODUCTION

Idiopathic Membranous nephropathy (IMN) is one of the most common causes of adult onset nephrotic syndrome worldwide. About 50% will slowly progress to renal failure if untreated.

METHODS

We did a retrospective study in patients with Idiopathic membranous nephropathy who were on follow-up between 2016-2018 at Madras medical college, Chennai. Clinical records, investigations, treatment and treatment response were analyzed. Risk stratification was done according to urine protein estimation, Modified Ponticelli regimen was administered in patients with high risk of renal failure and those with complications. They were followed up 6-12 months.

RESULTS

Among 61 patients with IMN, 37 were treated with Modified Ponticelli regimen after 6months of supportive treatment. Spontaneous remission was 14%, after mean follow up of 3.14 yrs total remission was 64.86 %( CR 43.24%; PR-21.62%) and 35.14% had no remission. Three patients progressed to CKD. Tacrolimus was initiated in non responders to IST. Analysis between IST responders and non responders shows those who presented with lesser proteinuria had statistically better outcome.

CONCLUSION

This retrospective study of IMN showed a reasonably better outcome. Seventeen per cent of patients had spontaneous remission and 64.86% achieved remission with Modified Ponticelli regimen.

Treatment of Idiopathic Membranous Nephropathy for Moderate or Severe Proteinuria: A Systematic Review and Network Meta-Analysis

OBJECTIVE

Numerous studies have demonstrated that the efficacy of drugs differs in idiopathic membranous nephropathy (IMN) patients with moderate or high proteinuria. However, there is no systematic comparison confirming it. This network meta-analysis (NMA) was performed to respectively compare the efficacy of ten IMN treatments in patients with moderate and high proteinuria and compare the risk of adverse events with 10 IMN regimens.

METHODS

Randomized controlled trials (RCTs) and observational studies analyzing the main therapeutic regimens for IMN were included from some databases. Network comparisons were performed to analyze the rates of total remission (TR), bone marrow suppression, and gastrointestinal symptoms. The surface under the cumulative ranking area (SUCRA) was calculated to rank interventions.

RESULTS

Seventeen RCTs and eight observational studies involving 1778 patients were pooled for comparison of ten interventions. Steroid + tacrolimus (TAC) showed the highest probabilities of TR whether patients had severe proteinuria or not (SUCRA 89.5% and 88.9%, separately). Rituximab (RTX) was more beneficial for TR on patients with proteinuria <8 g/d (SUCRA 66.0%) and was associated with a lower risk of bone marrow suppression and gastrointestinal symptoms (SUCRA 21.7% and 21.4%, separately). TAC + RTX and steroids + cyclophosphamide induced the highest rates of bone marrow suppression (SUCRA 90.6% and 88.3%, separately) and gastrointestinal symptoms (SUCRA 86.0% and 72.1%, separately).

CONCLUSIONS

Steroids + TAC showed significant efficacy in patients with all degrees of proteinuria, while RTX was more effective in patients with moderate proteinuria and was safer in bone marrow suppression and gastrointestinal symptoms.

Worsening membranous nephropathy in a patient with GIST treated with sunitinib

Tyrosine kinase inhibitors (TKI) are anticancer agents widely used for a variety of malignancies including gastrointestinal stromal tumours (GIST). Although generally well-tolerated, TKIs have been associated with a number of adverse events including hypertension, proteinuria and nephrotic syndrome. We present the case of a 70-year-old patient with metastatic GIST on long-standing sunitinib who developed hypertension, oedema and hypoalbuminemia with a rising serum creatinine and was found to have nephrotic syndrome. Workup revealed elevated antiphospholipase A2 receptor (PLA2R) antibody IgG titres and a kidney biopsy confirmed PLA2R-positive membranous nephropathy without findings of thrombotic microangiopathy. Cessation of sunitinib led to reduction in anti-PLA2R antibody IgG titres while resumption, due to concern for cancer progression, led to worsening symptoms. Treatment with rituximab led to undetectable anti-PLA2R IgG titres. We highlight the importance of maintaining a systematic approach for evaluating nephrotic syndrome and provide a case showing that TKIs can exacerbate underlying nephrotic syndrome.

Immune checkpoint inhibitor associated reactivation of primary membranous nephropathy responsive to rituximab

The same mechanisms that mediate antitumor immunity from checkpoint inhibitors (CPIs) can also lead to unintended targeting of normal tissues, characterized as immune-related adverse events (irAEs). Those with pre-existing autoimmune disease are believed to be particularly vulnerable for exacerbating underlying autoimmunity or inducing severe irAEs. We report the first case of CPI-associated reactivation of primary membranous nephropathy (MN) in a patient with pleural mesothelioma responding to immunotherapy. Due to its specificity in targeting B-lymphocytes, rituximab was used to treat primary MN with the expectation that this would not interfere with the benefits gained from T cell-mediated antitumor immunity. Rituximab was effective in treating CPI-associated reactivation of MN, and the patient was successfully rechallenged with nivolumab and maintained stable kidney function and sustained clinical antitumor effect. While exacerbation of pre-existing autoimmune diseases from CPIs is common, therapy for autoimmune reactivation can be rationally directed by an understanding of the immunosuppressive mechanism with goals of cancer treatment.

Prediction Value of Serum NGAL in the Diagnosis and Prognosis of Experimental Acute and Chronic Kidney Injuries

Sensitive and accurate serum biomarkers for monitoring acute and chronic kidney disease progression are more convenient and can better evaluate drug efficiency in pharmacological research. Neutrophil Gelatinase-associated Lipocalin (NGAL) is considered a hopeful early biomarker of acute kidney injury (AKI), but its utility in early prediction and prognosis of diabetic nephropathy (DN) and immune-mediated glomerulonephritis is still not clear. Moreover, detailed prognosis studies of NGAL in AKI are lacking, and most studies use a urine source. In the current study, through two experimental AKI and two chronic kidney injury animal models, serum NGAL (sNGAL) prediction values on diagnosis and prognosis of kidney injuries in animal disease models have been investigated thoroughly. Four experimental kidney disease models include cisplatin-induced and lipopolysaccharide (LPS)-induced AKI, streptozocin-induced diabetic nephropathy (DN), and cationized-bovine serum albumin (c-BSA)-induced membranous nephropathy (MN), respectively. The sNGAL concentration was measured at different stages of kidney injury (KI) in each experimental model, and receiver operating characteristic (ROC) analyses were performed to investigate the diagnosis efficiency of sNGAL for KI. Western blot and immunohistochemistry were used to measure the protein levels in the kidneys, and pathological analysis was used as the gold standard to confirm KI. Results suggest that sNGAL can predict early diagnosis of cisplatin-induced AKI accurately but is less powerful in later stages compared to blood urea nitrogen (BUN) and serum creatinine (Scr). sNGAL is sensitive but lacks specificity to evaluate early kidney injury for LPS-induced AKI under low-dosage LPS challenge. sNGAL is not an efficient biomarker for early diagnosis of STZ-induced DN, but sNGAL is an efficient predictor for the early diagnosis and prognosis of immune-mediated MN. In conclusion, application of sNGAL as a kidney injury biomarker to determine the diagnosis and prognosis in pharmacological studies is dependent on experimental animal models.

A case of denosumab-associated membranous nephropathy in a patient with rheumatoid arthritis

We herein report a case of anti-RANKL monoclonal antibody-associated membranous nephropathy (MN). A 67-year-old woman with a history of rheumatoid arthritis treated with prednisolone and methotrexate for more than 30 years and osteoporosis treated with eldecalcitol and teriparatide for 4 years had achieved a stable disease condition. Her kidney function was normal and her urinalysis was negative for hematuria and proteinuria. An anti-RANKL monoclonal antibody (denosumab) was administered for the treatment of osteoporosis. Four months later, proteinuria appeared (2.3 g/g creatinine) and remained positive for about 6 months, therefore, she was admitted to our hospital. An immunofluorescence study revealed fine granular deposits of immunoglobulin G (IgG) and C3 along the capillary walls. Staining for IgG subclasses showed positive staining for IgG1 (3+), IgG2 (1+), IgG3 (1+), and IgG4 (1+); phospholipase A2 receptor was negative. Electron microscopy showed partial subepithelial and intramembranous deposits and focal thickening of the glomerular basement membrane. No evidence of malignancy or infectious disease was seen. After cessation of denosumab, the proteinuria gradually improved. Based on the renal biopsy results and clinical course (development of marked proteinuria in the presence of denosumab with subsequent amelioration in the absence of the drug), we diagnosed the patient with secondary MN due to denosumab. This is the first reported case of denosumab-associated MN.

[Nephrotic syndrome in Crohn's disease]

BACKGROUND

The differential diagnosis of nephrotic syndrome is diverse. Systemic conditions and medication such as NSAIDs can cause this syndrome.

CASE DESCRIPTION

A 33-year-old male with Crohn's disease for which he was receiving adalimumab noticed he was gaining weight and had swollen ankles. Examination revealed nephrotic syndrome without renal insufficiency. Renal biopsy showed a membranous glomerulopathy. We excluded secondary causes of membranous glomerulopathy such as diabetes mellitus, systemic lupus erythematosus, viral infection or malignancy. We treated the patient with high-dose glucocorticoids on a weaning schedule and adalimumab was discontinued. This regimen resulted in complete remission. It is likely that the nephrotic syndrome with membranous glomerulopathy was associated with adalimumab.

CONCLUSION

In patients with nephrotic syndrome based on membranous glomerulopathy both primary and secondary causes, such as use of medication, need to be excluded.

[Nephrotic syndrome in multiple sclerosis patients who had undergone long-term interferon β-1b therapy]

A 59-year-old man (case 1) with multiple sclerosis (MS) presented with shortness of breath and general fatigue. He had been treated using interferon β-1b (IFNβ-1b) since he was 51 years of age. Laboratory test results showed hypoproteinemia and hypoalbuminemia, proteinuria, and absence of hematuria. He was diagnosed with nephrotic syndrome, and the administration of IFNβ-1b was stopped. Percutaneous renal biopsy was performed, and the histology revealed membranous nephropathy. A 33-year-old woman (case 2) with MS, who had been treated using IFNβ-1b for 7 years, was diagnosed with proteinuria during a medical checkup. She was referred to a nephrologist and was found to have hypoalbuminemia and proteinuria. A diagnosis of nephrotic syndrome was made, and IFNβ-1b therapy was stopped. The patient underwent percutaneous renal biopsy, and the histology revealed membranous nephropathy. Both patients were treated using intravenous methylprednisolone followed by oral prednisolone. Case 1 was administered ciclosporin orally, and his clinical symptoms and laboratory test results improved at first, but his laboratory test results subsequently showed recurrence of proteinuria. Case 2 was administered mizoribine orally, resulting in improvement in clinical symptoms and laboratory test results. Case 2 showed relapse of multiple sclerosis, but the symptoms were mild and were alleviated after steroid therapy. IFNβ therapy has several complications including nephropathy. Previously, several cases of nephrotic syndrome associated with IFNβ within 2 years of therapy were reported, but drug-induced nephropathy could appear after several years of the therapy as our cases. We should pay attention to nephrotic syndrome under using long-term IFNβ.

[Membranous nephropathy secondary to rheumatoid arthritis occurring during anti-TNFalpha therapy and responsive to second-line treatment with rituximab]

We report the case of a patient with rheumatoid arthritis (RA) who developed a membranous nephropathy (MN) with nephrotic syndrome while receiving etanercept, a fusion protein that binds specifically to TNFalpha and blocks its interaction with TNFalpha receptors. A 62-year-old man with RA treated with etanercept was admitted to our unit in March 2008 because of a full-blown nephrotic syndrome. Renal biopsy showed a typical MN. Since no improvement of proteinuria was observed after withdrawal of etanercept, we administered rituximab (1 g two weeks apart repeated after 6 months). The signs and symptoms of RA improved and proteinuria decreased from 7.2 g/24h to 2.3 g/24h. MN is an immunological glomerulonephritis that may complicate other immune-mediated diseases or may be triggered by a number of drugs. The clinical improvement of both RA and MN after rituximab may indirectly confirm the role of antibodies in the pathogenesis of these diseases, although the mechanisms of action of this drug in immunological disorders remain to be elucidated.

1,25-Dihydroxyvitamin D3 ameliorates podocytopenia in rats with adriamycin-induced nephropathy

OBJECTIVE

To investigate the role of α3β1 integrin and α/β-dystroglycan in protective effects of 1,25(OH)2D3 on podocytes in rats with adriamycin-induced nephropathy.

METHODS

Sprague-Dawley rats were randomly divided into three groups: control group (NC), nephropathy group (NE), and nephropathy+1,25(OH)2D3 group (ND). Rats in NE and ND group were injected intravenously with adriamycin (0.1 mg/10 g body weight) to induce nephropathy, and those in ND group were then subcutaneously treated with 1,25(OH)2D3 for 8 weeks. Urinary protein level, number of urine podocytes, foot process width and glomerulosclerotic index were determined. Nephrin and podocin mRNA and protein expressions were determined by RT-PCR and western blot, respectively. Podocyte density and expressions of α3β1 integrin and α/β-dystroglycan (DG) were analyzed by immunohistochemistry and western blot, respectively.

RESULTS

The increase in proteinuria, podocyturia and width of foot process in NE group were ameliorated after treatment with 1,25(OH)2D3 for 8 weeks. The glomerulosclerotic index was significantly decreased in ND group when compared with NE group. The podocyte density in ND group (10.3±1.64 cells/glomerulus) was significantly higher than that in NE group (8.43±1.75 cells/glomerulus) (p=0.008). 1,25(OH)2D3 treatment could significantly up-regulate the mRNA and protein expressions of nephrin and podocin, and the protein expressions of α3β1 integrin and α/β-DG.

CONCLUSION

The expressions of nephrin, podocin, α3β1 integrin and α/β-DG were decreased in rats with nephropathy. However, 1,25(OH)2D3 treatment could significantly up-regulate the expressions of nephrin, podocin, α3β1 integrin and α/β-DG proteins which might suppress podocyte detachment and podocytopenia.

Kinetics of adaptive immunity to cationic bovine serum albumin-induced membranous nephropathy

Membranous nephropathy is an autoimmune-mediated glomerulonephritis and a major cause of nephrotic syndrome. We studied the kinetics of adaptive immunity in the pathogenesis of membranous nephropathy in T1/T2 double transgenic mice (T1/T2 TG mice) that express human Thy1 protein under the control of interferon-gamma (INF-gamma) and mouse Thy1.1 protein under the control of interleukin (IL)-4. Nephropathy was induced by cationic bovine serum albumin. We found that splenocytes expressed a progressive Th2 response and a subsequent compensatory T-helper 1 (Th1) response, with a gradual augmentation of IL-4-producing Th2 cells and INF-gamma-producing Th1 cells. Increased Th2 marker expression was seen in peripheral blood and kidney cells, with the immunoglobulin G1 (IgG1) antibody isotype predominant in the serum and kidneys. We found that CD8+ T cells contribute more to the augmented INF-gamma production than CD4+ T cells. Moreover, CD19+ B cells demonstrated a greater production of IL-4 than the CD4+ T cells. Cytokine-related gene expression in kidneys and splenocytes showed an upregulation of proinflammatory Th1 and Th2 cytokines. Th2 cells but not Th1 cells were significantly correlated with serum cholesterol and proteinuria. Our study shows that both peripheral and renal immune reactions are strongly polarized toward Th2-type immune responses during the course of membranous nephropathy. The T1/T2 mouse model may help decipher the kinetic changes of adaptive immunity in glomerulonephritis.

Membranous Nephropathy Associated With Fluconazole Treatment

About 6% to 9% of cases of membranous nephropathy develop secondary to exposure to drugs. Fluconazole is a widely used antifungal agent that was never implicated in the development of membranous nephropathy. We report the case of a patient found to have membranous nephropathy secondary to fluconazole treatment. This patient had recurrent episodes of nephrotic syndrome caused by readministration of fluconazole. This is the first reported case of membranous nephropathy caused by fluconazole treatment and the first case report of the clinical course of recurrent membranous nephropathy caused by reexposure to this medication.

Membranous nephropathy associated with the relatively selective cyclooxygenase-2 inhibitor, etodolac, in a patient with early rheumatoid arthritis

Renal dysfunction and urinary abnormalities, which are usually related to drug toxicity, secondary amyloidosis, or those which overlap with other autoimmune conditions, are frequently observed in patients with rheumatoid arthritis. This is the first case report of membranous nephropathy in a patient with early-stage rheumatoid arthritis treated with the relatively selective cyclooxygenase-2 inhibitor, etodolac. The present case suggests that any kind of non-steroidal anti-inflammatory drug can cause membranous nephropathy; thus, physicians should be aware of this renal toxicity when prescribing these drugs.

Outcome and treatment of bucillamine-induced nephropathy

BACKGROUND

Bucillamine (BCL), a treatment for rheumatoid arthritis, occasionally causes proteinuria. Renal specimens are reported to show segmental granular deposition of immunoglobulin G, associated with membranous nephropathy. Long-term course and optimal treatment have remained unknown, and were investigated here.

METHODS

We examined clinical records of 400 patients treated with BCL for rheumatoid arthritis, at our hospital from 1998 to 2003, finding 17 with proteinuria and biopsy-proven BCL-induced nephropathy.

RESULTS

In all 17 patients, proteinuria resolved without loss of renal function between 3 and 85 months after discontinuing BCL (14.1 +/- 3.4). The only factor influencing time to remission was pathologic stage of membranous nephropathy (stage I vs. stage II or III: 11.5 +/- 4.8 vs. 21.6 +/- 3.3 months; p = 0.02). Maximal proteinuria, total amount of BCL, BCL exposure time, and use of prednisolone or other immunosuppressant agents did not significantly influence time until remission.

CONCLUSION

The most important therapeutic step in treating BCL-induced nephropathy is to discontinue BCL. Prednisolone or other immunosuppressant agents might not be effective.

Drug-induced glomerulopathies

Normal renal function depends upon an intact glomerular apparatus. Many drugs and chemicals are capable of damaging the glomerulus, causing its increased permeability to large molecules. Glomerular lesions are usually responsible for proteinuria and the nephrotic syndrome. This also holds true for the drug-induced glomerulopathies, of which membranous glomerulo-nephritis is the most frequent type of lesion encountered. Apart from this, several cases of different glomerular changes such as focal segmental glomerulosclerosis and crescentic glomerulonephritis have also been reported. The drug-induced glomerulopathies are probably immune mediated. This is, for instance, reflected in the fact that patients with drug-induced nephritic syndrome frequently have the HLA-B8 and DR3 antigens. In depth information is provided for the previously mentioned disorders.

Blunted renal dopaminergic system activity in HgCl2-induced membranous nephropathy

The present study evaluated the possible role of the renal dopaminergic system in the sodium retention of HgCl2-induced nephrotic syndrome. The time courses of urinary excretion of sodium, protein, dopamine and the precursor l-3,4-dihydroxyphenylalanine (L-Dopa) were evaluated in HgCl2-treated and control rats up to day 21. The renal aromatic l-amino acid decarboxylase (AADC) activity, the enzyme responsible for the synthesis of renal dopamine, was evaluated during negligible proteinuria accompanied with enhanced sodium retention (day 7), increased proteinuria accompanied with greatest sodium retention (day 14) as well as during increased proteinuria accompanied with negative sodium balance (day 21). Also, the influence of volume expansion (VE, 5% bw) and the effects of the D1-like agonist fenoldopam (10 microg kg bw(-1) min(-1)) on natriuresis and on proximal tubular Na+,K+-ATPase activity were examined on day 14. The daily urinary dopamine output and urinary dopamine/L-Dopa ratios were reduced in HgCl2-treated rats from day 2 and beyond. This was accompanied by a marked decrease in renal AADC throughout the study. During VE, the fenoldopam-induced inhibition of proximal tubular Na+,K+-ATPase activity was similar between HgCl2-treated and control rats. However, the urinary sodium excretion during fenoldopam infusion was markedly increased by 60% to 120% in control rats but was not altered in HgCl2-treated rats. It is concluded that HgCl2 nephrosis is associated with a blunted renal dopaminergic system activity. However, the lack of renal dopamine in HgCl2 nephrosis does not appear to be related with the overall renal sodium retention in a state of proteinuria.

Nephrotic syndrome in a multiple sclerosis patient treated with interferon beta 1a

BACKGROUND

Interferon beta has become standard therapy for reducing relapse frequency in relapsing/remitting Multiple Sclerosis (RRMS). Several different preparations are available including interferon beta 1a (Avonex, Rebif) and interferon beta 1b (Betaferon/Betaseron). For the most part these preparations have been considered safe. Recently there have been concerns relating to liver and now kidney toxicity.

CASE REPORT

We present a case of a 28-yr-old male who developed a severe case of nephrotic syndrome while being treated for relapsing/remitting Multiple Sclerosis (RRMS) with weekly injections of interferon beta 1a. SUBSEQUENT COURSE: The nephrosis resolved almost completely once the interferon was stopped and after immunosuppressive treatment. At its peak the daily protein loss was 35.82 g. Kidney biopsy demonstrated membranous glomerulonephritis.

DISCUSSION

Two other case reports of nephrotic syndrome have been reported in the literature. This latest (third) report suggests that the safety profile should be reexamined and at least raises the question of potential renal toxicity of interferons in MS.

Mouse model of membranous nephropathy induced by cationic bovine serum albumin: antigen dose-response relations and strain differences

BACKGROUND

Few well-characterized animal models have been developed to study the pathogenesis of membranous nephropathy (MN). We have developed a mouse model of MN induced by cationic bovine serum albumin (cBSA), and examined the role of genetic background on disease induction by assessing different mouse strains.

METHODS

cBSA in an optimum dose was given intravenously to 8-week-old female ICR, BALB/c and C57BL/6 mice for 4 weeks. The disease state was verified by renal histopathology as well as by serum and urine metabolic profiles. Serum concentrations of anti-cBSA immunoglobulins (Igs) and circulating immune complex (CIC) were assayed to study the mechanisms of initiation and progression. T-helper (Th) cell subsets in peripheral blood were examined using flow cytometry, and the Th1/Th2 subset distribution was determined by comparing the serum concentrations of IgG1 and IgG2a, using quantitative heterologous interpolation enzyme-linked immunosorbent assays.

RESULTS

Only ICR and BALB/c mice developed the typical clinical and pathological patterns of MN in response to an optimum dose of cBSA. Disease induction was dose related and strain specific. The serum concentrations of anti-cBSA were significantly higher in the strains that developed MN, but there were no differences in CIC concentrations. This suggests that in situ immune-complex glomerulonephritis may be involved in the development of MN. The Th2 type immune response may predominate in the ICR and BALB/c mice models, as the serum concentration of IgG1 was higher than that of IgG2a; moreover Th2 type strain specificity was necessary for the development of MN.

CONCLUSIONS

This improved mouse model of MN induced by cBSA more closely duplicates human MN than the other available models. Disease generation is antigen dose related and strain specific.

Adult onset Fanconi syndrome: extensive tubulo-interstitial lesions and glomerulopathy in the early stage of Chinese herbs nephropathy

A 33-year-old woman was transferred to our hospital with a 5-month history of taking Chinese herbal medicine containing aristolochic acid. She presented with metabolic acidosis, severe anemia, hypophosphatemia and uric aciduria, and generalized aminoaciduria and glycosuria, features which were consistent with the clinical manifestations of Fanconi syndrome. Renal biopsy was performed when her plasma creatinine was 0.7 mg/dl and creatinine clearance was 46 ml/min per 1.73 m(2). The renal specimen showed extensive interstitial edema with focal fibrosis, tubular atrophy, and focal glomerulopathy, which suggested the presence of glomerular endothelial damage or glomerular ischemia. Although steroid therapy ameliorated the plasma electrolyte levels, renal failure progressed, and hemodialysis therapy was initiated approximately 18 months after the time of renal biopsy. This patient demonstrated the early renal lesions of Chinese herbs nephropathy in association with various clinical manifestations. The characteristic glomerulopathy found in the present patient is considered to be an additional renal lesion, leading to the renal failure.

Clinical course of bucillamine-induced nephropathy in patients with rheumatoid arthritis

BACKGROUND

Bucillamine, a disease-modifying antirheumatic drug widely prescribed in Japan, is reported to be a cause of proteinuria. However, to date, the clinical course of the nephropathy associated with the use of bucillamine has not been described in detail.

METHODS

We analyzed renal biopsy findings from 10 patients with rheumatoid arthritis and concomitant bucillamine-induced nephropathy. Each patient was followed up until proteinuria had resolved.

RESULTS

Proteinuria appeared 2-11 months after the initiation of the treatment with bucillamine. Nine patients, who stopped bucillamine treatment immediately (within 3 months) after the onset of proteinuria, were diagnosed as having stage I membranous nephropathy. Only one patient, who used bucillamine for 9.5 months after the onset of proteinuria, was diagnosed as having stage II membranous nephropathy. In all patients with stage I membranous nephropathy, the proteinuria disappeared within 7 months after they stopped bucillamine treatment. On the other hand, in the patient with stage II membranous nephropathy, the proteinuria persisted for 14 months after the use of bucillamine was stopped. In all the patients, the proteinuria resolved completely without deterioration of renal function. None of the patients has experienced recurrence of proteinuria.

CONCLUSIONS

In patients with proteinuria induced by treatment with bucillamine, membranous nephropathy is the most common disorder. Immediate withdrawal of bucillamine results in prompt and complete resolution of proteinuria without deterioration of renal function.Bucillamine, a disease-modifying antirheumatic drug widely prescribed in Japan, is reported to be a cause of proteinuria. However, to date, the clinical course of the nephropathy associated with the use of bucillamine has not been described in detail.

Arterial Thrombosis due to Minimal Change Glomerulopathy Secondary to Nonsteroidal Anti-Inflammatory Drugs

The authors report a 49-year-old woman who had been treated with diclofenac for her back pain. Nephrotic syndrome followed by occlusion of the right profound femoral and popliteal arteries occurred. Successful thrombectomy was performed. Another nonsteroidal anti-inflammatory drug (NSAID) was administered by injection during hospitalization. Renal biopsy showed minimal change glomerulopathy (MCG). Remission was delayed despite large-dose steroid administration. The delayed remission in this patient may be caused by impaired renal function and the possible effect of a second period of NSAID administration. The authors present the first case of femoral arterial thrombosis associated with nephrotic syndrome secondary to NSAID-associated MCG. Careful history-taking and physical examination may detect early causes and complications of nephrotic syndrome. Any rechallenge of NSAID should be avoided.

Exogenous PDGF-D Is a Potent Mesangial Cell Mitogen and Causes a Severe Mesangial Proliferative Glomerulopathy

The PDGF family consists of at least four members, PDGF-A, -B, -C, and -D. All of the PDGF isoforms bind and signal through two known receptors, PDGF receptor-alpha and PDGF receptor-beta, which are constitutively expressed in the kidney and are upregulated in specific diseases. It is well established that PDGF-B plays a pivotal role in the mediation of glomerular mesangial cell proliferation. However, little is known of the roles of the recently discovered PDGF-C and -D in mediating renal injury. In this study, adenovirus constructs encoding PDGF-B, -C, and -D were injected into mice. Mice with high circulating levels of PDGF-D developed a severe mesangial proliferative glomerulopathy, characterized by enlarged glomeruli and a striking increase in glomerular cellularity. The PDGF-B-overexpressing mice had a milder proliferative glomerulopathy, whereas the mice overexpressing PDGF-C and those that received adenovirus alone showed no measurable response. Mitogenicity of PDGF-D and -B for mesangial cells was confirmed in vitro. These findings emphasize the importance of engagement of PDGF receptor-beta in transducing mesangial cell proliferation and demonstrate that PDGF-D is a major mediator of mesangial cell proliferation. Finally, this approach has resulted in a unique and potentially valuable model of mesangial proliferative glomerulopathy and its resolution.

Membranous glomerulopathy and acute interstitial nephritis following treatment with celecoxib

Both membranous glomerulopathy and acute interstitial nephritis have been reported to occur following treatment with non-steroidal anti-inflammatory drugs. We report the first cases of membranous glomerulopathy and acute interstitial nephritis following treatment with celecoxib (Celebrex), a selective COX-2 inhibitor. The rapid and complete resolution of both conditions following discontinuation of Celebrex strongly implicates this agent in disease pathogenesis. These cases enlarge the spectrum of potential renal toxicities of the COX-2-specific non-steroidal anti-inflammatory drugs.

A whitened face woman with nephrotic syndrome

Skin whitening cream from developing countries is a recognized source of chronic mercury poisoning. The authors report on a 34-year-old Indonesian domestic helper who presented with nephrotic syndrome secondary to membranous nephropathy. It was subsequently found that she used a skin whitening cream regularly that was found to contain a mercury level of almost 2,000 times above the allowable limit. Her blood and urinary mercury levels were both grossly elevated. Her symptoms improved after she stopped using the cream. However, she returned to her home country before chelating therapy could be arranged. Because mercury-containing skin products are still widely available in developing countries, the use of these products should be considered a possible cause of membranous nephropathy in immigrants from those countries.

Effects of carvedilol and BL-443 on kidney of rats with cyclosporine nephropathy

Effects of cyclosporine A on kidneys of rats and the effects of carvedilol or BL-443 on kidneys of rats with cyclosporine nephropathy were studied. Male rats (Wistar) were divided into four groups (n = 7). Three groups of rats were treated in single oral daily doses of 45 mg cyclosporine A/kg body weight to cause cyclosporine nephropathy. Two of the treated groups were then medicated either with carvedilol or BL-443 in single daily doses of 10 mg/kg b.w., and 1 ml doses of saline were given daily i.p. to the third group of rats. Animals were treated and medicated for 17 days. The rats of intact group had no treatment and medication. L-lactate dehydrogenase isoenzymes LD(1-4) in the kidney extracts were determined by polyacrylamide gel clectrophoresis. Significant differences of LD(1-4) pattern in kidneys between intact rats and each of the three groups of rats with cyclosporine nephropathy were found by F-test and t-test (p < 0.05). Treatment with cyclosporine A affected the LD(1-4) pattern in kidneys. On the other hand, no significant differences of LD(1-4) pattern in kidneys between rats with non-treated cyclosporine nephropathy and rats with cyclosporine nephropathy medicated with carvedilol or BL-443 were found.

Bucillamine induces membranous glomerulonephritis

A variety of renal histopathologic lesions, such as amyloidosis, mesangial proliferative glomerulonephritis, and membranous glomerulonephritis (MGN), are associated with rheumatoid arthritis (RA). Bucillamine (BCL), a disease-modifying antirheumatic drug, has a chemical structure and side-effect profile similar to that of d-penicillamine, which can induce MGN in RA. There are a few reports of MGN occurring in association with BCL treatment. However, lacking detailed analyses of immunoglobulin deposition in glomerular lesions, these studies did not elucidate the pathogenesis of BCL-induced MGN. We evaluated seven biopsy specimens from six patients with RA who had undergone BCL treatment with a mean BCL dose of 72.5 g before the appearance of proteinuria. Light microscopic evaluation showed mild to moderate mesangial proliferation. Two biopsy specimens showed spikes along glomerular capillary walls. Granular deposition of immunoglobulin G (IgG) along glomerular capillary walls was seen in all cases, and five specimens showed deposition of IgG2 and/or IgG3 components, in addition to IgG4. Furthermore, subepithelial dense deposits were distributed segmentally in four biopsy specimens on electron microscopy. IgG4, reported to be the predominant IgG subclass deposited, is distributed diffusely in idiopathic MGN. Thus, there were obvious differences between BCL-induced and idiopathic MGN in regard to both IgG subclasses deposited and deposition pattern within the glomerulus. Because IgG3 has the strongest affinity for C1q, these findings suggest that BCL-induced MGN activates the classical pathway more efficiently than idiopathic MGN and that the pathogenesis is different between these two diseases.

Immunoglobulin VH-gene usage of autoantibodies in mercuric chloride-induced membranous glomerulopathy in the rat

Brown-Norway (BN) and Dorus Zadel Black (DZB) rats develop a T-cell-dependent membranous glomerulopathy (MGP) with high proteinuria and antiglomerular basement membrane (GBM) autoreactive antibodies (Abs), upon exposure to mercuric chloride (HgCl2). Laminin is an important autoantigenic target of the anti-GBM Abs, absorbing approximately 30% of the anti-GBM reactivity. Although many anti-GBM Abs have undergone isotype switching, it is currently unclear whether affinity maturation occurs during the HgCl2-induced autoimmune response. To address this question we analysed the rearranged immunoglobulin heavy chain variable-region genes (VHDJH regions) of 15 mAbs that were previously obtained from HgCl2-treated rats. Seven of these mAbs exhibit reactivity towards laminin. Our study showed that the VH-gene usage of antilaminin mAbs is largely restricted to the PC7183 VH-gene family (six out of seven). In addition, we demonstrated that at least three out of six laminin reactive and five out of six non-laminin-binding mAbs are encoded by germline VH genes (a total of eight out of 12 mAbs). Of the eight mAbs that are encoded by germline VH genes, seven are of a non-immunoglobulin M (IgM) isotype, indicating that isotype switching has occurred in these mAbs in the absence of somatic mutations. The mutations observed in the VH genes of the four remaining mAbs do not provide strong evidence for antigenic selection. The data support the notion that B cells in this model of MGP are not subjected to affinity maturation and probably result from polyclonal B-cell activation.

Membranous nephropathy, hydrocarbon exposure and genetic variants of hydrocarbon detoxification

Modulation of biotransformation by genetic traits may be important in determining environmentally-induced nephrotoxicity. We conducted a case-control study to investigate the role of occupational hydrocarbon exposure, along with polymorphisms of the genes coding for N-acetyltransferase 2 (NAT2) and glutathione S-transferase mu (GSTmu), in the development of idiopathic membranous glomerulonephritis (IMGN). Patients (n=36) with biopsy-proven IMGN were matched with healthy controls for age, gender, and geographical area. Lifetime hydrocarbon exposure was assessed by a validated questionnaire. The polymorphisms of the NAT2 and GSTmu genes (GSTM1) were defined by use of a polymerase chain reaction on white-cell DNA from peripheral blood. Exposure to hydrocarbons was significantly greater in patients with IMGN than in controls (mean+/-SEM hydrocarbon exposure score 11 003+/-2955.7 vs. 4352+/-1418, p<0.02). NAT2 acetylator status was identical in patients and controls with 23 (63.9%) fast and 13 (36.1%) slow acetylators in each group. GSTmu was present in 15 (41.7%) patients and 16 (44.4%) controls. While occupational exposure to hydrocarbons remains a likely factor in its pathogenesis, further work is required to identify the genetic polymorphisms that modulate the risk of IMGN.

Collecting duct (Na+/K+)-ATPase activity is correlated with urinary sodium excretion in rat nephrotic syndromes

In puromycin aminonucleoside (PAN)-treated nephrotic rats, sodium retention is associated with increased (Na+/K+)-ATPase activity in the cortical collecting ducts (CCD). This study was undertaken to determine whether stimulation of (Na+/K+)-ATPase in the CCD is a feature of other experimental nephrotic syndromes, whether it might be responsible for renal sodium retention, and whether it is mediated by increased plasma vasopressin levels or activation of calcineurin. For this purpose, the time courses of urinary excretion of sodium and protein, sodium balance, ascites, and (Na+/K+)-ATPase activities in microdissected CCD were studied in rats with PAN or adriamycin nephrosis or HgCl2 nephropathy. The roles of vasopressin and calcineurin in PAN nephrosis were evaluated by measuring these parameters in Brattleboro rats and in rats treated with cyclosporin or tacrolimus. Despite different patterns of changes in urinary sodium and protein excretion in the three nephrotic syndrome models, there was a linear relationship between CCD (Na+/K+)-ATPase activities and sodium excretion in all three cases. The results also indicated that there was no correlation between proteinuria and sodium retention, but ascites was present only when proteinuria was associated with marked reduction of sodium excretion. Finally, the lack of vasopressin in Brattleboro rats or the inhibition of calcineurin by administration of either cyclosporin or tacrolimus did not prevent development of the nephrotic syndrome in PAN-treated rats or stimulation of CCD (Na+/K+)-ATPase. It is concluded that stimulation of Na(+/K+)-ATPase in the CCD of nephrotic rats might be responsible for sodium retention and that this phenomenon is independent of proteinuria and vasopressin and calcineurin activities.

Clopidogrel and membranous nephropathy

Membranous nephropathy with nephrotic syndrome occurred in a patient with anterior myocardial infarction 2 months after the start of clopidogrel treatment. Sensitisation by prior treatment with ticlopidine is discussed.