Treatment of primary focal segmental glomerulosclerosis

Ferroptosis-related genes, a novel therapeutic target for focal segmental glomerulosclerosis

Recent studies have suggested that ferroptosis participates in various renal diseases. However, its effect on focal segmental glomerulosclerosis remains unclear. This study analyzed the GSE125779 and GSE121211 datasets to identify the differentially expressed genes (DEGs) in renal tubular samples with and without FSGS. The Cytoscape was used to construct the protein-protein interaction network. Moreover, the ferroptosis-related genes (FRGs) were obtained from the ferroptosis database, while ferroptosis-related DEGs were obtained by intersection with DEGs. The target genes were analyzed using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis. The GSE108112 dataset was used to verify the expression of target FRGs. Besides, we built the mRNA-miRNA network regarding FRGs using the NetworkAnalyst database, and circRNAs corresponding to key miRNAs were predicted in the ENCORI database. In this study, 16 ferroptosis-related DEGs were identified between FSGS and healthy subjects, while five co-expressed genes were obtained by three topological algorithms in Cytoscape. These included the most concerned Hub genes JUN, HIF1A, ALB, DUSP1 and ATF3. The KEGG enrichment analysis indicated that FRGs were associated with mitophagy, renal cell carcinoma, and metabolic pathways. Simultaneously, the co-expressed hub genes were analyzed to construct the mRNA-miRNA interaction network and important miRNAs such as hsa-mir-155-5p, hsa-mir-1-3p, and hsa-mir-124-3p were obtained. Finally, 75 drugs targeting 54 important circRNAs and FRGs were predicted. This study identified the Hub FRGs and transcriptomic molecules from FSGS in renal tubules, thus providing novel diagnostic and therapeutic targets for FSGS.

Physiologically-based pharmacokinetic model of sparsentan to evaluate drug-drug interaction potential

Sparsentan is a dual endothelin/angiotensin II receptor antagonist indicated to reduce proteinuria in patients with primary IgA nephropathy at high risk of disease progression. In vitro data indicate that sparsentan is likely to inhibit or induce various CYP enzymes at therapeutic concentrations. Sparsentan as a victim and perpetrator of CYP3A4 mediated drug-drug interactions (DDIs) has been assessed clinically. A mechanistic, bottom-up, physiologically-based pharmacokinetic (PK) model for sparsentan was developed based on in vitro data of drug solubility, formulation dissolution and particle size, drug permeability, inhibition and induction of metabolic enzymes, and P-glycoprotein (P-gp) driven efflux. The model was verified using clinical PK data from healthy adult volunteers administered single and multiple doses in the fasted and fed states for a wide range of sparsentan doses. The model was also verified by simulation of clinically observed DDIs. The verified model was then used to test various DDI simulations of sparsentan as a perpetrator and victim of CYP3A4 using an expanded set of inducers and inhibitors with varying potency. Additional perpetrator and victim DDI simulations were performed using probes for CYP2C9 and CYP2C19. Simulations were conducted to predict the effect of complete inhibition of P-gp inhibition on sparsentan absorption and clearance. The predictive simulations indicated that exposure of sparsentan could increase greater than two-fold if co-administered with a strong CYP3A4 inhibitor, such as itraconazole. Other potential DDI interactions as victim or perpetrator were all within two-fold of control. The effect of complete P-gp inhibition on sparsentan PK was negligible.

Association Between NPHS2 p.R229Q and Focal Segmental Glomerular Sclerosis/Steroid-Resistant Nephrotic Syndrome

Aim

NPHS2 is the coding gene of podocin. This study aims to investigate the association between NPHS2 p.R229Q (rs61747728), the most frequently reported missense variant of NPHS2, and focal segmental glomerular sclerosis (FSGS) or steroid-resistant nephrotic syndrome (SRNS) based on typing the variant in a Chinese FSGS/SRNS cohort and conducting a meta-analysis.

Method

We recruited patients with FSGS or SRNS and healthy individuals. To conduct a meta-analysis, all studies on p.R229Q and FSGS/SRNS were searched from public databases.

Results

In total, we enrolled 204 patients with FSGS, 61 patients with SRNS [46 with FSGS, 9 with minimal change disease (MCD), and six patients with IgA nephropathy (IgAN)], and 100 healthy controls. Unexpectedly, p.R229Q was absent in the patients from our cohort. By meta-analysis of 21 studies including 2,489 patients with FSGS/SRNS and 6,004 healthy controls, we confirmed that the A allele of p.R229Q was significantly associated with increased risk of FSGS/SRNS (allelic OR = 1.9, 95% CI = 1.44-2.52, P < 0.001). However, the subgroup analysis showed that the association between p.R229Q and FSGS/SRNS was true only in Caucasians (allelic OR = 2.14, 95%CI = 1.54-2.98, P < 0.001) and in early-onset patients (allelic OR: 2.13, 95% CI = 1.21-3.76, P = 0.009).

Conclusion

NPHS2 p.R229Q may play an important role in enhancing the susceptibility of FSGS/SRNS, especially in ethnicity of Caucasian and age of early-onset patients.

Later Response to Corticosteroids in Adults With Primary Focal Segmental Glomerular Sclerosis Is Associated With Favorable Outcomes

INTRODUCTION

Guidelines advise initial therapy with corticosteroids (CSs) in patients with presumed primary focal segmental glomerular sclerosis (pFSGS). Many patients do not achieve complete remission (CR) after 8 or 16 weeks. Although these patients are considered steroid resistant, clinical outcomes are ill defined.

METHODS

A retrospective cohort study of patients with pFSGS who were referred between January 1995 and December 2014. Data of clinical presentation until last follow-up were collected from patient records.

RESULTS

A total of 51 patients (median age 47 years, 20 female/31 male) were included (median follow-up 7.1 years). There were 10 patients who achieved partial response (PR) at 8 weeks. High-dose CS monotherapy was continued for a median of 17 weeks (interquartile range [IQR] 11-21 weeks) (total duration 56 weeks [IQR 28-83 weeks]). With CSs, the cumulative incidence of CR + PR was 18% and 35%, respectively. Of 24 patients with persistent nephrotic-range proteinuria, 22 received additional immunosuppressive (IS) therapy, resulting in CR in 3 (14%) and PR in 11 patients (50%). A decrease of >20% of proteinuria at 8 weeks predicted response. In addition, 8 patients (36%) were considered primary nonresponders. A genetic cause was found in 2 patients. Proteinuria at end of follow-up was 1.2 g (IQR 0.4-3.0 g/24 hours or g/10 mmol creatinine). Renal survival at 3, 5, and 10 years was 92%, 87%, and 64%, respectively.

CONCLUSION

Patients with presumed pFSGS often respond late to IS therapy. A decrease in proteinuria of >20% after 8 weeks of therapy is a predictor of responsiveness. Regardless of CR in some patients, improved biomarkers are needed to predict response/outcomes in patients with pFSGS.

Focal Segmental Glomerulosclerosis in Paediatric Population of South Punjab Pakistan: A Tertiary Care Hospital Experience

Objectives:

To find out frequency, clinicopathological features, response of treatment and outcome among children with primary focal segmental glomerulosclerosis (FSGS).

Methods:

This retrospective, non-interventional medical charts review study was conducted from a period of January 2011 to January 2020 at Pediatric Department of Nishtar Medical University Hospital, Multan, Pakistan. During the nine years study period, children of both genders, aged less than 16 years, with renal biopsies proven FSGS were included. Patient’s demographic along with clinical and laboratory data, urine dipstick for proteinuria, renal functions, 24 hours urinary protein and ultrasonography findings of kidneys, ureters and bladder (KUB) were noted from case records. Response rates of various treatment options and their outcome like remission, partial remission, no remission with stable kidney disease & no remission with progression of kidney disease were noted.

Results:

During the study duration, out of 307 renal biopsies performed in glomerulonephritis cases, 124 (40.4%) had primary FSGS. In 124 primary FSGS cases, mean age was 8.83±3.05 years while most of the children, 70 (56.5%) were above 10 years of age. Majority of the cases, 64 (51.6%) were male. Mean follow up duration was noted to be 28.35+18.47 months. Most of the cases, 68 (54.8%) were found to have complete remission, 22 (17.7%) partial remission while 11 (8.9%) progressed to ESKD.

Conclusions:

Among children, frequency of primary FSGS was high at our setting. Most of the cases achieved sustained remission rates with the help of immunosuppressive drugs. Cyclosporine and tacrolimus were found to be the most effective drugs.

Do effects of sodium-glucose cotransporter-2 inhibitors in patients with diabetes give insight into potential use in non-diabetic kidney disease?

PURPOSE OF REVIEW

Our aim was to review the rationale for the role of sodium-glucose cotransporter-2 inhibitors (SGLT-2i) as renoprotective therapy in patients with and without diabetes.

RECENT FINDINGS

SGLT-2i are antihyperglycemic agents, approved for treating type 2 diabetes to reduce glycosylated hemoglobin, type A1c. Primary glucoregulatory effects occur through selective inhibition of SGLT-2 at the renal proximal tubule promoting glucosuria leading to blood glucose lowering. From a hemodynamic perspective, SGLT-2 inhibition is also associated with decreased glomerular hyperfiltration, an effect that is mediated through natriuresis and tubuloglomerular feedback. With renal injury and progressive nephron loss, diabetic kidney disease, and nondiabetic chronic kidney diseases share overlapping phenotypes exhibiting single nephron hyperfiltration, along with increased proteinuria. Importantly, the impact of SGLT-2 inhibition on renal and systemic hemodynamic function, including effects on lowering blood pressure, hyperfiltration, and plasma volume, are independent of blood glucose lowering and instead are because of natriuresis. Accordingly, large clinical trials with SGLT-2i investigating the potential use of SGLT-2i in patients without diabetes are now underway.

SUMMARY

Based on prominent nonglycemic effects, the clinical use of SGLT-2i as renoprotective therapy may extend to nondiabetic chronic kidney diseases subtypes, which could help to address a large, unmet clinical need.

Optimal management of primary focal segmental glomerulosclerosis in adults

Focal segmental glomerulosclerosis (FSGS) is a frequent glomerular kidney disease that is revealed by proteinuria or even nephrotic syndrome. A diagnosis can be established from a kidney biopsy that shows focal and segmental glomerulosclerosis. This histopathological lesion may be caused by a primary podocyte injury (idiopathic FSGS) but is also associated with other pathologies (secondary FSGS). The first-line treatment for idiopathic FSGS with nephrotic syndrome is a prolonged course of corticosteroids. However, steroid resistance or steroid dependence is frequent, and despite intensified immunosuppressive treatment, FSGS can lead to end-stage renal failure. In addition, in some cases, FSGS can recur on a graft after kidney transplantation: an unidentified circulating factor may be implicated. Understanding of its physiopathology is unclear, and it remains an important challenge for the scientific community to identify a specific diagnostic biomarker and to develop specific therapeutics. This study reviews the treatment of primary FSGS and the recurrence of FSGS after kidney transplantation in adults.

Primary and Recurrent Focal Segmental Glomerulosclerosis Closely Link to Serum Soluble Urokinase-type Plasminogen Activator Receptor Levels

BACKGROUND

Serum soluble urokinase-type plasminogen activator receptor (suPAR) is implicated in the pathogenesis of native and recurrent focal segmental glomerulosclerosis (FSGS). It is elevated in two-thirds of subjects with primary FSGS, but not in people with other glomerular diseases that can differentiate FSGS and other glomerular diseases.

METHODS

We measured the serum soluble urokinase receptor levels and determined their association with clinical and pathologic data in 86 patients with primary FSGS, 5 repeat renal biopsy FSGS, and 6 recurrent FSGS post-transplantation. Healthy controls and patients with minimal change disease and membranous nephropathy were used as controls. The suPAR levels were measured by commercial enzyme-linked immunosorbent assay kits.

RESULTS

Patients with primary FSGS (median: 4232, interquartile range 1299-9714 pg/mL) had significantly higher levels of suPAR than those of patients with minimal change disease (median: 2784 pg/mL), membranous nephropathy (median: 3478 pg/mL), and healthy individuals (median: 1994 pg/mL). There was no significant difference in suPAR levels between the 65 patients with minimal change disease and 85 patients with membranous nephropathy. The suPAR levels increased in the 5 repeated renal biopsy FSGS and 6 recurrent FSGS post-transplantation.

CONCLUSIONS

The suPAR levels were significantly but positively correlated with FSGS, not only primary FSGS but also recurrent FSGS post-transplantation, but negatively correlated with other glomerular diseases. Thus, suPAR levels can differentiate primary FSGS and other glomerular diseases.

The treatment of idiopathic focal segmental glomerulosclerosis in adults

Focal segmental glomerulosclerosis (FSGS) is the histologic end point of many disease processes that affect the kidney. Clinically, adults with FSGS present with proteinuria that may be accompanied by the nephrotic syndrome. Once identifiable (secondary) causes are excluded, the diagnosis of idiopathic FSGS, a challenging glomerular disease to understand and manage, is made. On the basis of mostly retrospective data, first-line treatment for idiopathic FSGS patients with nephrotic-range proteinuria is a prolonged course of corticosteroids. However, steroid resistance is common and portends an increased risk of long-term decline in kidney function and end-stage kidney disease in these patients compared with responders. Multiple other immunosuppression regimens have been used in steroid-resistant FSGS, some of which have been studied in randomized controlled trials. Here, we review the data on the treatment for idiopathic FSGS in adults.

Angiotensin-converting enzyme gene polymophism in adult primary focal segmental glomerulosclerosis

BACKGROUND

Primary focal segmental glomerulosclerosis (FSGS) accounts for a third of biopsy-proven primary glomerulonephritis in Malaysia. Pediatric studies have found the insertion/deletion (I/D) polymorphism of the angiotensin-converting enzyme (ACE) gene to be associated with renal disease progression. The aim of this study was to determine the prevalence of the ACE (I/D) genotypes in adult primary FSGS and its association with renal outcome on follow-up.

METHODS

Prospective observational study involving primary FSGS patients was conducted. Biochemical and urine tests at the time of study were compared to the time of the diagnosis and disease progression analyzed. ACE gene polymorphism was identified using polymerase chain reaction amplification technique and categorized into II, ID and DD genotypes.

RESULTS

Forty-five patients with a median follow-up of 3.8 years (interquartile range: 1.8 - 5.6) were recruited. The commonest genotype was II (n = 23, 51.1%) followed by ID (n = 19, 42.2%) and DD (n = 3, 6.7%). The baseline characteristics were comparable between the II and non-II groups at diagnosis and at study recruitment except that the median urine protein-creatinine index was significantly lower in the II group compared to the non-II group (0.02 vs. 0.04 g/mmol (P = 0.03). Regardless of genotypes, all parameters of renal outcome improved after treatment.

CONCLUSION

The II followed by ID genotypes were the predominant ACE gene alleles in our FSGS. Although the D allele has been reported to have a negative impact on renal outcome, treatment appeared to be more important than genotype in preserving renal function in this cohort.

Primary focal and segmental glomerulosclerosis and soluble factor urokinase-type plasminogen activator receptor

Primary focal and segmental glomerulosclerosis (FSGS) may be due to genetic or acquired etiologies and is a common cause of nephrotic syndrome with high morbidity that often leads to end-stage renal failure. The different available therapeutic approaches are unsuccessful, in part due to partially deciphered heterogeneous and complex pathophysiological mechanisms. Moreover, the term FSGS, even in its primary form, comprises a histological description shared by a number of different causes with completely different molecular pathways of disease. This review focuses on the latest developments regarding the pathophysiology of primary acquired FSGS caused by soluble factor urokinase type plasminogen activator receptor, a circulating permeability factor involved in proteinuria and edema formation, and describes recent advances with potential success in therapy.

Delayed development of pulmonary hemorrhage in a patient with positive circulating anti-neutrophil cytoplasmic antibody: a clinical dilemma

Detection of circulating anti-neutrophil cytoplasmic antibody (ANCA) provides a powerful clue in the diagnosis of vasculitis, but the clinical interpretation of the results is difficult in some cases. Here, we describe the case of a 65-year-old man who underwent hemodialysis due to focal segmental glomerulosclerosis and abruptly developed hemoptysis 14 years after a renal biopsy. At the time of the biopsy, computed tomography (CT) showed interstitial shadows in the lungs and pleural thickening, indicating pneumoconiosis that was accompanied by tuberculosis. Circulating myeloperoxidase-ANCA (10.5–32.5 U/ml) was subsequently noted, but the significance of this observation was unclear due to the preexisting disorders in the lungs and kidneys. Potent immunosuppressive therapies were avoided because of the pulmonary lesions and decreased renal function. There were few changes noted on follow-up CT, but infiltrative shadows emerged in the bilateral lungs, consistent with hemoptysis. The hemorrhagic shadows completely disappeared shortly after initiation of steroid therapy, with normalization of the serum ANCA level. Herein, we report this case, with an emphasis on the clinical dilemma faced in deciding the appropriate treatment. The findings in the case provide deep insights into clinical management of ANCA-positive patients.

Current and emerging treatments for idiopathic focal and segmental glomerulosclerosis in adults

Idiopathic focal and segmental glomerular sclerosis is a frequent cause of nephrotic syndrome and end-stage renal disease. The pathogenesis is still unknown, although the body of evidence suggests that focal and segmental glomerular sclerosis is caused by a not clearly identified circulating factor that alters the permselectivity of the glomerular barrier. Proteinuria is followed by podocyte injury. Glucocorticoids, calcineurin inhibitors, cytotoxic agents and mycophenolate mofetil, either given alone or in combination, may obtain complete or partial remission of proteinuria in 50-60% of patients and protect them from end-stage renal disease, but the remaining patients are resistant to the available drugs. A number of new drugs, including rituximab, galactose and antifibrotic agents, are under investigation.

Plasma soluble urokinase receptor levels are increased but do not distinguish primary from secondary focal segmental glomerulosclerosis

In this study, we measured soluble urokinase receptor levels, a possible permeability factor, in the plasma of patients with primary focal segmental glomerulosclerosis (FSGS) and determined their association with clinical and pathological data in 74 patients with primary FSGS. Healthy donors and patients with minimal change disease, membranous nephropathy, and secondary FSGS were used as controls. The plasma-soluble urokinase receptor levels, measured by commercial ELISA kits, of patients with primary FSGS (median: 2923, interquartile range 2205-4360 pg/ml) were significantly higher than those of patients with minimal change disease (median 2050 pg/ml), membranous nephropathy (median 2029 pg/ml), and normal individuals (median 1739 pg/ml). There was no significant difference in plasma-soluble urokinase receptor levels between the 74 patients with primary and 14 patients with secondary FSGS. The soluble urokinase receptor levels increased in the order of tip variant, to a not otherwise specified variant and a cellular variant. The soluble urokinase receptor levels were significantly but negatively correlated with creatinine clearance at presentation but positively correlated with crescent formation in patients with primary FSGS. During follow-up, receptor levels decreased significantly in patients with complete remission. Thus, plasma-soluble urokinase receptor levels did not differentiate primary and secondary FSGS, and although significantly elevated in FSGS, they showed considerable overlap with other glomerular diseases.

Circulating suPAR in two cohorts of primary FSGS

Overexpression of soluble urokinase receptor (suPAR) causes pathology in animal models similar to primary FSGS, and one recent study demonstrated elevated levels of serum suPAR in patients with the disease. Here, we analyzed circulating suPAR levels in two cohorts of children and adults with biopsy-proven primary FSGS: 70 patients from the North America-based FSGS clinical trial (CT) and 94 patients from PodoNet, the Europe-based consortium studying steroid-resistant nephrotic syndrome. Circulating suPAR levels were elevated in 84.3% and 55.3% of patients with FSGS patients in the CT and PodoNet cohorts, respectively, compared with 6% of controls (P<0.0001); inflammation did not account for this difference. Multiple regression analysis suggested that lower suPAR levels associated with higher estimated GFR, male sex, and treatment with mycophenolate mofetil. In the CT cohort, there was a positive association between the relative reduction of suPAR after 26 weeks of treatment and reduction of proteinuria, with higher odds for complete remission (P=0.04). In the PodoNet cohort, patients with an NPHS2 mutation had higher suPAR levels than those without a mutation. In conclusion, suPAR levels are elevated in geographically and ethnically diverse patients with FSGS and do not reflect a nonspecific proinflammatory milieu. The associations between a change in circulating suPAR with different therapeutic regimens and with remission support the role of suPAR in the pathogenesis of FSGS.

Treatment of primary FSGS in adults

Over the last 20 years, primary FSGS has emerged as one of the leading causes of idiopathic nephrotic syndrome in adults, particularly among African Americans. In nephrotic patients, progression to ESRD often occurs over the course of 5-10 years, whereas non-nephrotic patients and those entering a remission have an extremely favorable prognosis. As a result, it is in patients who remain persistently nephrotic despite conservative therapy that a more aggressive therapeutic approach is taken. Primary FSGS was once considered an entity nonresponsive to prednisone or immunosuppressive agents, but it has become apparent over the last 20 years that a substantial portion of nephrotic adults with primary FSGS do respond to treatment with a significantly improved prognosis. The recent histologic classification proposed for FSGS has provided additional insights into the prognosis and response to therapy. This article reviews the current knowledge regarding the presentation, prognosis, and therapeutic approach in adults with primary FSGS.

Collapsing focal segmental glomerulosclerosis: Current concepts

Collapsing focal segmental glomerulosclerosis (cFSGS), also known as collapsing glomerulopathy is currently classified under the rubric of FSGS. However, its defining morphological features are in stark contrast to those observed in most other variants of FSGS. During the early stage of the disease, the lesion is characterized pathologically by an implosive segmental and/or global collapse of the glomerular capillary tufts, marked hypertrophy and hyperplasia of podocytes, and severe tubulointerstitial disease. With advancement of the disease, segmental and/or global glomerulosclerosis is also observed in association with the collapsing lesions. The etiology of this enigmatic disorder is still elusive, but a growing list of diseases/conditions is being reported in association with this morphological pattern of renal parenchymal injury. The pathogenesis of cFSGS involves discreet epithelial cell injury leading to cell cycle dysregulation and a proliferative cellular phenotype. From the clinical perspective, cFSGS is notorious for its propensity to affect black people, a high incidence and severity of nephrotic syndrome, marked resistance to empirical therapy, and rapid progression to end-stage renal disease. The lesion has also been reported in transplanted kidneys either as recurrent or de novo disease, frequently leading to graft loss. Most cases have been reported in western countries, but the lesion is also being increasingly recognized in the tropical regions. The recent increase in reporting of cFSGS partly reflects a true increase in the incidence and partly a detection bias. There is no specific treatment for the disorder at present. Newer insights into the pathogenesis may lead to the development of targeted and specific therapy in near future. There is an urgent need to increase awareness of the lesion among pathologists and nephrologists, especially those from developing countries, to ensure accurate diagnosis and appropriate managment. With the accumulation of more and more data, it is hoped that the prevailing confusion about the nosological identity of the lesion will also be resolved in a more logical way.

[Pathogenesis and treatment of idiopathic nephrotic syndrome in adults]

Idiopathic nephrotic syndrome is the most frequent glomerular disease in children and in young adults. While genetic analyses have provided new insights into disease pathogenesis through the discovery of several podocyte genes mutated in distinct forms of inherited nephrotic syndrome, the molecular bases of minimal change nephrotic syndrome and focal and segmental glomerulosclerosis with relapses remain unclear. Although immune cell disorders, which may involve both innate and adaptive immunity, appear to play a role in the pathogenesis of steroid sensitive minimal change nephrotic syndrome, the mechanisms by which they induce podocyte dysfunction remain unresolved. It was postulated that podocyte injury results from a circulating factor secreted by abnormal T cells, but the possibility that bipolarity of the disease results from a functional disorder shared by both immune cells and the podocytes is not excluded. Minimal change nephrotic syndrome relapses are associated with an expansion of T and B cell compartments and production of growth factors as well as many cytokines. Dysfunction of T cells is supported by several findings including, inhibition of a type IV hypersensitivity reaction and unclassical T helper polarization, resulting from transcriptional interference between Th1 and Th2 transcriptional factors. A low serum level of some IgG fractions is frequently observed suggesting a defect in T-B cell cooperation, which remains to be explored. In this review, we discuss recent advances in the pathogenesis and the therapy of idiopathic nephrotic syndrome.

Raised serum creatinine at presentation does not adversely affect steroid response in primary focal segmental glomerulosclerosis in adults

BACKGROUND

There is no information in international literature on the mode of presentation, laboratory and clinical features, treatment and prognosis of primary focal segmental glomerulosclerosis (FSGS) in adults in Pakistan.

METHODS

This is a retrospective review of 124 adults (≥17 years) with a diagnosis of primary FSGS who presented to the adult nephrology clinic at Sindh Institute of Urology and Transplantation between January 1995 and June 2006. The clinical records and biopsy reports were reviewed to determine the demographic, clinical, laboratory and pathologic features, treatment responses and outcome of the disease. Renal biopsies were performed and evaluated by light microscopy, immunofluorescence and electron microscopy. Standard therapeutic regimens and response to therapy definitions were used. Outcome data were obtained at last follow-up.

RESULTS

Mean age of all patients was 30.9 ± 13.6 years (range: 17-85 years). Of these, 86 (69%) were males and 38 (31%) females, with a male to female ratio of 2.2:1. Of 124 patients, 79 (63.7%) were treated with steroids for a median duration of 5 months. Remission was achieved in 40 (50.6%) patients. Relapse occurred in 14 (17.7%) steroid-treated patients. These achieved sustained remission with retreatment. None of the steroid-treated patients went into end-stage renal disease over a mean follow-up of 2.3 years.

CONCLUSIONS

Results from this study show that half of adults with primary FSGS achieve sustained remission with prolonged steroid treatment and consequently exhibit an excellent prognosis for long-term outcome. Moreover, raised serum creatinine at presentation does not in itself adversely affect steroid response in adults with primary FSGS.

Renoprotective effects of long-term oral nicotine in a rat model of spontaneous proteinuria

Many proteinuric renal conditions are accompanied by renal inflammation. Nicotine is known to have anti-inflammatory properties and is used in oral form to help subjects quit smoking. A potential anti-inflammatory role of nicotine in proteinuric renal diseases has not been investigated to date. We therefore evaluated the effects of oral nicotine in a rat model of proteinuria-induced renal inflammation. We used a well-established model of adult (24 wk of age) male Munich-Wistar-Frömter rats. Animals were given three different physiological doses of nicotine in drinking water for 28 wk until 52 wk of age (long term). A group without nicotine served as a parallel control. At 52 wk of age, the control group had a 2.1 times reduction in creatinine clearance, 3.2 times increase in urinary protein excretion, an increased focal glomerulosclerosis (FGS) score, increased glomerular desmin deposition, decreased glomerular podocin, and a higher accumulation of macrophages and myofibroblasts compared with 24-wk-old animals. Oral treatment with nicotine dose dependently preserved renal function and halted proteinuria progression, which were independent of blood pressure reduction. It also reduced FGS, desmin deposition, podocin loss, and density of renal macrophages and myofibroblasts. Nicotine also reduced the level of gene expression of the renal inflammatory markers monocyte chemoattractant protein and vascular cell adhesion molecule-1. In conclusion, long-term oral nicotine preserved kidney function, reduced proteinuria, reduced renal inflammation, and protected progression of renal structural damage in a rat model of proteinuria. We further suggest evaluating nicotine as a potential additional therapeutic option for treating proteinuric kidney diseases.

Reversibility of pamidronate-associated glomerulosclerosis

Bisphosphonates such as pamidronate are widely used in the treatment of patients with lytic bony lesions secondary to breast cancer or multiple myeloma, yet they have been associated with deterioration of renal function and histopathological changes in the kidney. There have been recent reports associating the use of pamidronate with the development of the collapsing variant of focal segmental glomerulosclerosis (CFSGS), a rapidly progressive variant of focal segmental glomerulosclerosis that leads to end-stage renal disease. We describe five patients who developed worsening renal function, proteinuria, and nephrotic syndrome while taking pamidronate; three of them had biopsy-proven CFSGS. Pamidronate was discontinued, and a longitudinal follow-up was performed for 10 to 23 months. One patient was able to discontinue hemodialysis, and all patients experienced improvement in renal function and a decrease in proteinuria. In some patients who develop pamidronate-associated CFSGS, renal damage appears to be reversible if the syndrome is recognized early and pamidronate is stopped.

Nephrotic syndrome due to focal segmental glomerulosclerosis occurring in early pregnancy

Physiological proteinuria is common during pregnancy, but pathological proteinuria may also occur. Nephrotic range proteinuria most commonly occurs due to preeclampsia, but primary renal disease may also occur. We present a case of a woman who presented with nephrotic range proteinuria and nephrotic syndrome at an early stage of her second pregnancy. Due to proteinuria, haematuria, progressive symptoms and high need for medical treatment, renal biopsy was performed and she was noted to have focal segmental glomerulosclerosis (FSGS). She commenced immunosuppression but remained nephrotic during pregnancy. She delivered a healthy baby boy at 35 weeks gestation. Postpartum she remained nephrotic, and developed further complications requiring renal replacement therapy. Despite a successful pregnancy, this case of FSGS highlights that despite aggressive treatment FSGS in pregnancy is often associated with adverse renal outcome. We discuss investigations, including renal biopsy and empiric treatment options in this report.

Antroquinonol reduces oxidative stress by enhancing the Nrf2 signaling pathway and inhibits inflammation and sclerosis in focal segmental glomerulosclerosis mice

Oxidative stress, inflammation, and fibrosis are involved in the development and progression of focal segmental glomerulosclerosis (FSGS), a common form of idiopathic nephrotic syndrome that represents a therapeutic challenge because it has a poor response to steroids. Antroquinonol (Antroq), a purified compound, is a major active component of a mushroom, namely Antrodia camphorata, that grows in the camphor tree in Taiwan, and it has inhibitory effects on nitric oxide production and inflammatory reactions. We hypothesized that Antroq might ameliorate FSGS renal lesions by modulating the pathogenic pathways of oxidative stress, inflammation, and glomerular sclerosis in the kidney. We demonstrate that Antroq significantly (1) attenuates proteinuria, renal dysfunction, and glomerulopathy, including epithelial hyperplasia lesions and podocyte injury; (2) reduces oxidative stress, leukocyte infiltration, and expression of fibrosis-related proteins in the kidney; (3) increases renal nuclear factor E2-related factor 2 (Nrf2) and glutathione peroxidase activity; and (4) inhibits renal nuclear factor-κB (NF-κB) activation and decreases levels of transforming growth factor (TGF)-β1 in serum and kidney tissue in a mouse FSGS model. Our data suggest that Antroq might be a potential therapeutic agent for FSGS, acting by boosting Nrf2 activation and suppressing NF-κB-dependent inflammatory and TGF-β1-mediated fibrosis pathways in the kidney.

Novel therapies for resistant focal segmental glomerulosclerosis (FONT) phase II clinical trial: study design

Background

The lack of adequate randomized clinical trials (RCT) has hindered identification of new therapies that are safe and effective for patients with primary focal segmental glomerulosclerosis (FSGS), especially in patients who fail to respond to corticosteroids and immunosuppressive therapies. Recent basic science advances have led to development of alternative treatments that specifically target aberrant pathways of fibrosis which are relevant to disease progression in FSGS. There is a need for a flexible Phase II study design which will test such novel antifibrotic strategies in order to identify agents suitable for phase III testing.

Methods/Design

The Novel Therapies for Resistant Focal Segmental Glomerulosclerosis (FONT) project is a multicenter Phase I/II RCT designed to investigate the potential efficacy of novel therapies for resistant FSGS. Adalimumab and galactose will be evaluated against conservative therapy consisting of the combination of lisinopril, losartan and atorvastatin. The sample size is defined to assure that if one of the treatments has a superior response rate compared to that of the other treatments, it will be selected with high probability for further evaluation. Comparison of primary and secondary endpoints in each study arm will enable a choice to be made of which treatments are worthy of further study in future Phase III RCT.

Discussion

This report highlights the key features of the FONT II RCT including the two-step outcome analysis that will expedite achievement of the study objectives. The proposed phase II study design will help to identify promising agents for further testing while excluding ineffective agents. This staged approach can help to prevent large expenditures on unworthy therapeutic agents in the management of serious but rare kidney diseases

Trial Registration

ClinicalTrials.gov, NCT00814255

The podocyte as a direct target of immunosuppressive agents

Podocytes play a key role in maintaining the blood-urine barrier for high-molecular-weight proteins. They are considered to be terminally differentiated, and podocyte loss cannot be compensated by regenerative proliferation. Various diseases leading to podocyte damage and loss result in proteinuria and cause nephrotic syndrome. Therefore, direct therapeutical strategies to protect podocytes in disease situations are a logical concept to prevent disease or to delay disease progression. Acquired podocytopathies like idiopathic focal segmental glomerulosclerosis and minimal change disease are historically considered as immunological diseases. Therefore, immunosuppressive agents such as steroids and calcineurin inhibitors are the commonly used treatment strategies. However, the causative disease mechanisms behind these treatment strategies remain elusive. Recent evidence shows that immunosuppressive agents, in addition to the effect on the immune system, directly influence the unique structure and function of podocytes. In this context, the actin cytoskeleton of the podocyte and cytokines such as vascular endothelial growth factor play a pivotal role. In this review, we summarize the direct effects on podocytes obtained in vivo and in vitro after treatment with calcineurin inhibitors, mTOR inhibitors and glucocorticoids. These direct effects could play a key role in the treatment concepts of podocytopathies with an important impact on the long-term renal function in patients with pharmacological immunosuppression.

Collapsing FSGS: a clinicopathologic study of 10 cases from Pakistan

BACKGROUND

Idiopathic collapsing focal segmental glomerulosclerosis (FSGS), a rare variant of FSGS, is of interest because of its increasing incidence, frequent association with black race, HIV-1 infection, and intravenous (IV) drug abuse. This lesion has not been reported from Pakistan until now.

METHODS

We reviewed our 14-year native renal biopsies record and identified 10 cases of this entity (July 1995-July 2009). Patients' demographic and clinicopathologic data were collected from case files. Renal biopsies were studied by light microscopy, immunofluorescence microscopy, and electron microscopy. A control group of 124 patients with noncollapsing FSGS was selected for comparison of clinical, laboratory, and outcome parameters.

RESULTS

All the patients were young adults (mean age: 22.4 +/- 4.6 years). The majority were males (9 vs. 1 female). All presented with nephrotic syndrome (24-h urinary protein: 6.7 +/- 9.22 g). In addition, 8 had mild to moderate renal failure (serum creatinine: 4.12 +/- 4.6 mg/dl). No history of heroin or IV drug abuse was elicited and all tested negative for HIV. Only two patients (20%) responded to steroid treatment, while eight (80%) did not. Five of the patients (50%) developed endstage renal disease after a mean interval of 18 months.

CONCLUSION

Idiopathic collapsing FSGS is increasingly being reported in patients who have no HIV infection or history of IV drug abuse. There is a need for increased awareness among pathologists all over the world to diagnose this condition to guide nephrologists and patients regarding the poor prognosis of this form of FSGS.

The accumulated experience with the use of mycophenolate mofetil in primary glomerulonephritis

IMPORTANCE OF THE FIELD

The use of mycophenolate mofetil (MMF) has been extended from renal transplantation to the treatment of glomerulonephritis. MMF has been used in patients with steroid- and ciclosporin A (CsA)-dependent or -resistant idiopathic nephrotic syndrome and in patients with deteriorating renal function or adverse reactions to other drugs. MMF has been also used in patients with membranous and IgA nephropathy after failure of other regimens as well as initial treatment.

AREAS COVERED IN THIS REVIEW

The rationale of MMF treatment in primary glomerulonephritis is based in its antifibrotic and antiproteinuric effects. The mechanism of action is described; the results of cohort and randomized trials in minimal change disease, focal segmental glomerulosclerosis, idiopathic membranous nephropathy and IgA nephropathy are presented along with the adverse reactions profile and the expert opinion.

WHAT THE READER WILL GAIN

This is an up-to-date review providing insight on this novel agent that is increasingly used in the therapeutics of primary glomerulonephritis.

TAKE HOME MESSAGE

Although the results are conflicting, MMF seems to be effective at least in some patients, who do not respond to corticosteroids, ciclosporin or cytotoxic drugs. However, the experience with MMF in primary glomerulonephritis is limited and further research is required in order to establish MMF in the treatment of patients with glomerular disease.

Collapsing FSGS: a clinicopathologic study of 10 cases from Pakistan

BACKGROUND

Idiopathic collapsing focal segmental glomerulosclerosis (FSGS), a rare variant of FSGS, is of interest because of its increasing incidence, frequent association with black race, HIV-1 infection, and intravenous (IV) drug abuse. This lesion has not been reported from Pakistan until now.

METHODS

We reviewed our 14-year native renal biopsies record and identified 10 cases of this entity (July 1995-July 2009). Patients' demographic and clinicopathologic data were collected from case files. Renal biopsies were studied by light microscopy, immunofluorescence microscopy, and electron microscopy. A control group of 124 patients with noncollapsing FSGS was selected for comparison of clinical, laboratory, and outcome parameters.

RESULTS

All the patients were young adults (mean age: 22.4 +/- 4.6 years). The majority were males (9 vs. 1 female). All presented with nephrotic syndrome (24-h urinary protein: 6.7 +/- 9.22 g). In addition, 8 had mild to moderate renal failure (serum creatinine: 4.12 +/- 4.6 mg/dl). No history of heroin or IV drug abuse was elicited and all tested negative for HIV. Only two patients (20%) responded to steroid treatment, while eight (80%) did not. Five of the patients (50%) developed endstage renal disease after a mean interval of 18 months.

CONCLUSION

Idiopathic collapsing FSGS is increasingly being reported in patients who have no HIV infection or history of IV drug abuse. There is a need for increased awareness among pathologists all over the world to diagnose this condition to guide nephrologists and patients regarding the poor prognosis of this form of FSGS.

TRPC6 mutational analysis in a large cohort of patients with focal segmental glomerulosclerosis

BACKGROUND

Mutations in the TRPC6 gene have been reported in six families with adult-onset (17-57 years) autosomal dominant focal segmental glomerulosclerosis (FSGS). Electrophysiology studies confirmed augmented calcium influx only in three of these six TRPC6 mutations. To date, the role of TRPC6 in childhood and adulthood non-familial forms is unknown.

METHODS

TRPC6 mutation analysis was performed by direct sequencing in 130 Spanish patients from 115 unrelated families with FSGS. An in silico scoring matrix was developed to evaluate the pathogenicity of amino acid substitutions, by using the bio-physical and bio-chemical differences between wild-type and mutant amino acid, the evolutionary conservation of the amino acid residue in orthologues, homologues and defined domains, with the addition of contextual information.

RESULTS

Three new missense substitutions were identified in two clinically non-familial cases and in one familial case. The analysis by means of this scoring system allowed us to classify these variants as likely pathogenic mutations. One of them was detected in a female patient with unusual clinical features: mesangial proliferative FSGS in childhood (7 years) and partial response to immunosupressive therapy (CsA + MMF). Asymptomatic carriers of this likely mutation were found within her family.

CONCLUSIONS

We describe for the first time TRPC6 mutations in children and adults with non-familial FSGS. It seems that TRPC6 is a gene with a very variable penetrance that may contribute to glomerular diseases in a multi-hit setting.

Idiopathic collapsing glomerulopathy in children

BACKGROUND

Collapsing glomerulopathy (CG) is a clinically and pathologically distinct variant of focal segmental glomerulosclerosis (FSGS). Pathologically similar lesions have been reported in adults and children with human immuno-deficiency virus (HIV) infection. However, there is a recent interest in the recognition of this variant in the absence of HIV infection.

AIM

To evaluate the clinical presentation and outcome of our pediatric patients with idiopathic CG.

METHODS

A sum of six children with idiopathic CG, aged 1-7 years at presentation, were retrospectively identified. Clinical data and renal biopsy were reviewed for all patients. Serum creatinine and estimated GFRs at presentation and last follow-up were compared using the Wilcoxon signed rank test and the risk factors for occurrence of ESRD analyzed using the Cox proportional hazard models.

RESULTS

Steroid-resistant nephrotic syndrome with or without azotemia was the presenting clinical finding in all the cases. The median serum creatinine values at onset and last follow-up were 1.05 and 1.25 mg/dl, respectively (p = 0.128). Following immunosuppressive therapy one patient achieved complete remission of proteinuria, and four were in partial remission. The remaining one patient did not show any change in proteinuria at 6 months of therapy. Two of the six patients progressed to end-stage renal disease within a median follow-up period of 27 months (range 14-96 months).

CONCLUSIONS

Collapsing glomerulopathy is an aggressive variant of focal segmental glomerulosclerosis. All patients with CG should be screened for the underlying etiology, and patients with idiopathic CG should be offered a trial of immunosuppressive therapy.

[Focal segmental glomerulosclerosis]

Focal segmental glomerulosclerosis is a glomerular injury with typical morphology detectable by light microscopy. It has different histological subtypes and clinical symptoms. These different subtypes were recently systematized (Columbia classification). Focal segmental glomerulosclerosis is considered as the major type of podocytopathies, because podocytes are affected at each type of glomerular injury. Besides the primary forms of focal segmental glomerulosclerosis, an increased number of the secondary types are recognized. The wide use of drugs for renal protection in general and the long term administration of steroid therapy in some primary (idiopathic) cases are new elements among the therapeutic possibilities.

Cyclosporin in idiopathic glomerular disease associated with the nephrotic syndrome : workshop recommendations

Management of idiopathic glomerular disease associated with nephrotic syndrome (INS) remains controversial and one of the most complex areas relates to utilization of the drug cyclosporin. This is despite its demonstrated effectiveness in several histologic types of the INS in randomized controlled trials. Cyclosporin is effective in inducing remission of proteinuria in approximately 80% of steroid-sensitive cases of minimal change disease (MCD). Cyclosporin is also effective in both the induction of remission and long-term preservation of renal function in steroid-dependent/-resistant MCD and steroid-resistant focal segmental glomerulosclerosis (FSGS). The overall response rate in FSGS is lower than in MCD, and long-term therapy (>12 months) may be required to both achieve remission and sustain it. Cyclosporin therapy is also of benefit in reducing proteinuria in 70-80% of patients with steroid-resistant membranous nephropathy (MGN). In MGN, the maximum benefit is often delayed compared to MCD (>12 weeks). Cyclosporin is generally well tolerated and safe. The major concern remains the nephrotoxicity, but with careful monitoring of the patient's renal function; minimizing the maintenance dose and utilizing repeat renal biopsy in those receiving long-term therapy, this risk can be minimized. The algorithms have been developed derived from the best evidence in the literature in each of the histologic types to help provide a guide to the integration of cyclosporin into the management of INS for the practicing nephrologist.

FoxP3 mRNA transcripts and regulatory cells in renal transplant recipients 10 years after donor marrow infusion

BACKGROUND

We update more favorable 10-year deceased donor kidney transplant survival in 63 recipients infused perioperatively with donor vertebral body bone marrow (DBMC-i) vs. 219 noninfused controls having equivalent immunosuppression and demographics. We questioned if this was associated with putatively regulatory FoxP3 mRNA and cell phenotypes (CD4+CD25+high percentages and high DC2:DC1 ratios) in DBMC-i vs. noninfused controls.

METHODS

Baseline studies were performed on peripheral blood lymphocytes (PBLs) vs. marrow in normal laboratory volunteers of CD4+CD25+high percentages and DC2:DC1 by flow cytometry, and FoxP3 mRNA in CD3+ cells by real-time polymerase chain reaction. Similar studies were performed on PBL of the majority of the 10-year patients remaining with graft function: 21 (of the remaining 37) DBMC-i vs. 55 (of the remaining 105) controls.

RESULTS

In normal subjects, all parameters were significantly higher in marrow than in PBL, supporting our previous reports of ex vivo DBMC immunoregulation. At 9.8+/-.02 years posttransplant in DBMC-i vs. controls, death-censored percent graft failure was 17.5% vs. 32.9% (P=0.02) with 247.6+/-24 vs. 79.9+/-3.1 (mean+/-SE) FoxP3 copies/5,000 CD3+ cells (P=0.0001). PBL CD4+CD25+high percentages were lower, but DC2:DC1 values higher in both recipient groups than in end-stage renal disease patients who had lower FoxP3 levels (40.8+/-5.9, P<0.0001), consistent with non-CD4+CD25+high T regulatory cells generated long-term posttransplant. Individual higher FoxP3 values correlated with higher iliac crest chimerism in DBMC-i, but not in controls (with 50-fold lower chimerism). In chronically rejecting controls, FoxP3 was further decreased.

CONCLUSIONS

Peritransplant DBMC-i has higher 10-year renal transplant acceptance, chimerism, and FoxP3 mRNA in thus-far unclarified regulatory cell phenotypes.

Focal and segmental glomerulosclerosis in children: a longitudinal assessment

Recent data suggest that the histologic finding of focal and segmental glomerulosclerosis (FSGS) is increasing among children. There are, however, limited longitudinal pediatric data on prevalence, demographics, and steroid responsiveness in FSGS. We identified 201 consecutive nephrotic children diagnosed between 1977 and 2002 with 2 years follow-up; 51% had undergone renal biopsy due to steroid sequelae or resistance; 48 children with FSGS were diagnosed. Compared with non-FSGS children, FSGS children were older at diagnosis (6.9 years vs 4.4 years, P<0.02), more likely girls (54% vs 28%, P<0.02), Black or Hispanic (42% vs 16%, P<0.001), and the FSGS was more likely to be steroid resistant (73% vs 10%, P<0.001). To assess for longitudinal differences, we grouped children by presentation: pre-1985, between 1985 and 1995, and post-1995. There was no difference in proportion of children biopsied or diagnosed with FSGS during each interval. Among FSGS children, there was no difference in racial or gender composition in each period, but there was a difference in age at diagnosis (2.6 vs 5.7 vs 8.5 years; P=0.01), also observed in the non-FSGS children (2.2 vs 3.9 vs 4.9 years; P=0.02). In contradistinction to non-FSGS children, there was a marked increase in steroid resistance with FSGS (43% vs 62% vs 86%; P=0.03).

A Case Report of Plasmapheresis and Cyclophosphamide for Steroid-Resistant Focal Segmental Glomerulosclerosis: Recovery of Renal Function After Five Months on Dialysis

We describe a patient who presented with nephrotic syndrome and progressive renal failure with biopsy findings of focal segmental glomerulosclerosis (FSGS). He progressed rapidly to end-stage renal disease (ESRD) and remained hemodialysis dependent for five months despite high dose prednisone therapy. Initiation of plasmapheresis and low dose oral cyclophosphamide resulted in the prompt return of urine output and renal recovery. He remains off dialysis with stable renal function (creatinine clearance = 40 mL/min) two years later. This is the first report of late rescue from apparent ESRD due to FSGS with combined plasmapheresis and low dose oral cyclophosphamide.

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.

Recessive NPHS2 (Podocin) mutations are rare in adult-onset idiopathic focal segmental glomerulosclerosis

Recessive NPHS2 (podocin) mutations account for up to approximately 30% of steroid-resistant idiopathic FSGS in children and are associated with a reduced risk for disease recurrence after renal transplantation. R229Q, a missense variant that is present in 3.6% of the white population, has been implicated as a common disease-causing mutation. Given these clinical implications, we examined the role of NPHS2 mutations in a cohort of patients with adult-onset FSGS. We used denaturing HPLC to screen for heterozygous and homozygous gene variants in PCR-amplified DNA fragments that contained all exons and splice junctions of NPHS2. Bidirectional sequencing was performed to define all of the gene variants detected. With the use of the denaturing HPLC in a single-blind pilot study, 40 of 43 known NPHS2 mutations were detected from 22 pediatric patients with FSGS to establish a test sensitivity of 93%. This screen then was applied to 87 adult patients with idiopathic FSGS (15 steroid-sensitive, 63 steroid-resistant, and nine familial cases). In this latter cohort, compound heterozygous mutations were detected only in one patient with steroid-sensitive FSGS (R229Q and Q285fsX302) and no homozygous mutations. Overall, R229Q accounted for eight (80%) of ten of the putative mutant alleles that were detected in the study cohort. Contrary to the pediatric experience, recessive NPHS2 mutations are rare in this study population, suggesting that the pathogenesis of FSGS in adults may differ from that in children. These data do not support R229Q as a disease-causing mutation for steroid-resistant FSGS.

Mechanisms of disease: focal segmental glomerulosclerosis

Focal segmental glomerulosclerosis (FSGS), a subtype of "idiopathic nephrotic syndrome", is not a single disease, but a lesion that initially affects the glomerulus followed by the tubulointerstitium and renal vessels. The term 'FSGS' does not accurately encompass the various pathologic features of the glomerulus, which are not always focal, segmental or sclerotic. Particular variants of FSGS, such as collapsing glomerulopathy and the glomerular tip lesion, exemplify the nosologic uncertainty inherent in the classification of glomerular lesions. Pathologic variation notwithstanding, all pathologic processes that affect the podocyte lead to one of the histologic subtypes of FSGS. This specialized cell type has essential roles in maintaining the integrity of glomerular architecture, resisting endocapillary hydraulic pressure and hindering egress of proteins into the urinary space. Once initiated, podocyte lesions and ensuing fibrosis are usually irreversible, at least in human forms of FSGS. Remarkable progress has been made in unraveling the mechanisms of podocyte dysregulation that accompany the cellular variants of FSGS and in identifying genetic mutations affecting proteins of the slit diaphragm. Hopefully, this progress will drastically improve treatments for what is one of the most difficult therapeutic challenges to confront the nephrologist.

Expression of synaptopodin and GLEPP1 as markers of steroid responsiveness in primary focal segmental glomerulosclerosis

The crucial involvement of podocyte failure in the development of hereditary focal segmental glomerulosclerosis (FSGS) indicates that specific podocyte proteins are closely related to podocyte function and biology. We hypothesized that podocyte failure, reflected by alteration of these proteins, leads not only to FSGS but also to resistance to steroid therapy. We investigated the association between expression of synaptopodin and glomerular epithelial protein 1 (GLEPP1) and response to corticosteroid therapy in primary FSGS. The subjects of this retrospective study were 17 adult patients with primary FSGS with nephrotic syndrome (NS) seen at Fukuoka Red Cross Hospital between 1979 and 2001. They were divided into two groups according to the response to steroid therapy at 6months: responders (n=10) and non-responders (persistence of nephrotic-range proteinuria, n=7). Expression levels of synaptopodin and GLEPP1 were examined immunohistochemically using image analysis software. Low expression levels of both proteins were associated with poor steroid responsiveness in FSGS. The average gray values for synaptopodin and GLEPP1 expression in responders vs. non-responders were 9.0+/-0.7 (mean+/-S.E.M.) vs. 6.3+/-0.9 (P=0.04) and 9.6+/-1.2 vs. 6.0+/-1.0 (P=0.04), respectively. The percentages of glomerular area staining for synaptopodin and GLEPP1 in responders vs. non-responders were 15.4+/-2.7% vs. 8.1+/-1.2% (P=0.045) and 11.9+/-1.6% vs. 6.0+/-1.3% (P=0.02), respectively. Synaptopodin expression correlated with the severity of proteinuria and with GLEPP1 expression. Reduced expression of both synaptopodin and GLEPP1 is associated with poor response to steroid therapy in primary FSGS.

A Prospective, Open-Label Trial of Sirolimus in the Treatment of Focal Segmental Glomerulosclerosis

Calcineurin inhibitors are effective therapy for steroid-resistant focal segmental glomerulosclerosis (FSGS) but are associated with significant morbidity and nephrotoxicity. Sirolimus is a novel immunosuppressive agent that is structurally related to tacrolimus but demonstrates no long-term nephrotoxicity. For determination of the efficacy of sirolimus in reducing proteinuria, a prospective, open-label trial was conducted of 21 patients with idiopathic, steroid-resistant FSGS. A complete response was defined as <300 mg protein/24 h after 6 mo, whereas a partial response was defined as a 50% reduction in baseline proteinuria. After 6 mo of therapy, sirolimus induced complete remission in four (19%) of 21 patients and partial remissions in eight (38%). Among sirolimus-responsive patients, 6 mo of therapy decreased proteinuria from a mean of 8.8 +/- 1.7 to 2.1 +/- 0.5 g/24 h (P = 0.0003). In responsive patients, GFR was maintained (45 +/- 6 versus 47 +/- 7 ml/min per 1.73 m2 at 6 mo) throughout the study, whereas nonresponders tended to decrease (31 +/- 4 versus 28 +/- 5 ml/min per 1.73 m2). Using dextran sieving analysis, complete or partial response was associated with an increase in the glomerular ultrafiltration coefficient (K(f), 7 +/- 1. versus 8 +/- 0.9 units at 6 mo; P < 0.05). Glomerular permselectivity and K(f) tended to decrease in nonresponders (8.2 +/- 1.9 versus 6.2 +/- 1.3 units at 6 mo; P = 0.07). Patients with complete remission had a higher GFR (45 +/- 6 versus 31 +/- 4 ml/min per 1.73 m2) at the end of 6 mo compared with nonresponders. In patients with steroid-resistant FSGS, sirolimus reduced proteinuria and glomerular pore size and increased K(f) in patients with steroid-resistant FSGS.

Use of Mycophenolate Mofetil in Autoimmune and Renal Diseases

Progress in understanding the pathogenesis and treatment of rheumatologic and glomerular diseases such as systemic lupus erythematosus and particularly lupus nephritis has been closely linked with the development of newer immunosuppressive agents. With improved patient survival following the institution of cyclophosphamide and corticosteroid therapy, longer-term management issues came to the forefront, especially how to decrease adverse effects of the immunosuppressive regimen. Many of the immunosuppressive regimens used in lupus patients were first established as efficacious and safe through their use in solid organ transplantation. Mycophenolate mofetil (MMF) is now widely used in the field of transplantation. Following anecdotal reports describing benefits of MMF in lupus and lupus nephritis patients, small studies and finally large randomized, controlled trials have established the use of MMF in these patients, particularly those with lupus nephritis. MMF use in other rheumatologic and renal diseases has been evaluated in only smaller studies and very few randomized controlled trials. Nevertheless, many studies currently are ongoing with this immunosuppressive agent. This article will review the published data and the experience of two major New York medical centers with the use of MMF in autoimmune and renal diseases.