Treatment of primary focal segmental glomerulosclerosis

Treatment and outcome of adult patients with primary focal segmental glomerulosclerosis in five UK renal units

BACKGROUND

Focal segmental glomerulosclerosis (FSGS) is the least studied of the causes of idiopathic nephrotic syndrome, and there are few specific guidelines for treatment.

AIM

To review data from five UK renal units to investigate whether adult patients with FSGS were treated uniformly, and to examine the effect of treatment on proteinuria and survival.

DESIGN

Retrospective record review.

METHODS

We examined electronic records of patients with idiopathic FSGS for information on baseline clinical parameters, treatment regimens and outcomes.

RESULTS

Of 136 patients with primary FSGS and nephrotic range proteinuria, 76 (56%) were treated with prednisolone and of this group, 59% were treated with additional immunosuppression. Among the treated patients, the total remission rate (complete and partial) was 67%, and one hospital achieved a remission rate of 80%. Treated patients had a significantly higher remission rate than those who were not treated. Remission was associated with a 5-year survival off dialysis of 94%, compared with 53% if remission was not achieved. Baseline serum creatinine and remission were independently associated with survival off dialysis in a multivariate Cox proportional hazards model.

DISCUSSION

Patients with primary FSGS and nephrotic range proteinuria, who are treated with corticosteroids, are more likely to enter remission than those who are not treated. Remission rates of up to 80% can be achieved with prolonged treatment, and remission is an independent predictor of survival off dialysis. Patients who do not achieve remission have a poor prognosis. Further clarification of optimal treatment regimens requires additional, prospective studies.

Impact of cyclosporin on podocyte ZO-1 expression in puromycin aminonucleoside nephrosis rats

Puromycin aminonucleoside (PAN)-induced nephrosis is a well-described model of human idiopathic nephrotic syndrome, but the mechanism of PAN's effect is not completely understood. To investigate whether proteinuria in the PAN model is associated with an alteration of zonula occludens-1 (ZO-1) expression within the glomeruli, and whether cyclosporin A (CsA) has an effect on proteinuria and ZO-1 expression in this model, eighteen Sprague Dawley (SD) rats were assigned into three groups. Twelve rats received a single intraperitoneal injection of PAN (15 mg/100 g). The other six rats received an equal volume of saline (normal control group; control). CsA solution was administered intraperitoneally once a day for 20 days after the PAN injection (n=6, PAN+CsA). The remaining six rats received PAN, but they didn't receive CsA (n=6, PAN). Compared to control rats (35.1+/-5.4 mg/day), the 24-hour urinary protein excretion on day 18 was significantly higher in the PAN rats (1021.9+/-128.9 mg/day, p<0.01), and the CsA treatment partly reversed the increase in proteinuria in the PAN rats (556.4+/-102.3 mg/day, p<0.05). Glomerular ZO-1 protein expressions were significantly increased in the PAN rats as compared to the control group on day 20 (176%, p<0.01). CsA treatment for 20 days in the PAN rats inhibited the increase in ZO-1 protein expression by 71.1% (p<0.05). CsA treatment significantly diminished the glomerular ZO-1 expression in the PAN rats as assessed by immunohistochemistry. CsA treatment significantly reduced proteinuria and the diminished glomerular ZO-1 expression in a PAN nephrosis rat model. These findings suggest the potential role of the slit diaphragm associated proteins in the development of the nephrotic syndrome, and CsA decreased the proteinuria probably by a direct action on the expression of these proteins in podocytes. Further investigations are needed to clarify the role of slit diaphragm associated proteins in the development of PAN nephrosis.

Glomerular tip lesion: a distinct entity within the minimal change disease/focal segmental glomerulosclerosis spectrum

BACKGROUND

The glomerular tip lesion (GTL) is a distinctive but controversial histopathologic lesion occurring in patients with idiopathic nephrotic syndrome. The relationship of GTL to minimal change disease (MCD) and idiopathic focal segmental glomerulosclerosis (FSGS) has been disputed.

METHODS

In order to define the clinical features and natural history of GTL, we retrospectively reviewed the presenting clinical features, biopsy findings and outcome of 47 cases. Presenting clinical features of GTL were compared to those of controls with MCD (N= 61) or idiopathic FSGS (N= 50).

RESULTS

The cohort of GTL consisted of 45 adults and two children (mean age 47.5 years; range 12 to 79 years), including 76.6% Caucasians and 53% males. At presentation, 93.6% of patients had edema, 89.1% had nephrotic syndrome (mean urine protein 8.31 g, mean serum albumin 2.27 g/dL, and mean cholesterol 340.6 mg/dL), and 34.8% had renal insufficiency. Mean time from onset of renal disease to biopsy was 2.4 months. At biopsy, glomerular segmental lesions included GTL alone in 26%, GTL and peripheral lesions in 6%, GTL and indeterminate lesions in 36%, and GTL with peripheral and indeterminate lesions in 32%. No initial biopsy contained perihilar sclerosis and most (81%) segmental lesions were cellular. Follow-up data were available in 29 patients, of whom 21 received steroids alone and eight received sequential therapy with steroids and a cytotoxic agent. At a mean follow-up of 21.5 months, 58.6% of patients achieved complete remission of nephrotic syndrome, 13.8% had partial remission, and 27.6% had persistent nephrotic proteinuria. Only one patient progressed to end-stage renal disease (ESRD). Predictors of nonremission included severity of proteinuria at presentation and % peripheral lesions. When compared to controls with MCD and idiopathic FSGS, GTL more closely resembled MCD with respect to high incidence of nephrotic syndrome (P < 0.001), severity of proteinuria (P < 0.05), short duration from onset to biopsy (P < 0.001), and absence of chronic tubulointerstitial disease (P < 0.0054).

CONCLUSION

Within the MCD/FSGS spectrum, GTL is a distinctive and prognostically favorable clinical-pathologic entity whose presenting features and outcome more closely approximate those of MCD.

A combined low-density lipoprotein apheresis and prednisone therapy for steroid-resistant primary focal segmental glomerulosclerosis in children

BACKGROUND

Treatment of steroid-resistant (SR) primary focal segmental glomerulosclerosis (FSGS) remains a major challenge in nephrology. A prospective study was conducted to clarify the therapeutic role of low-density lipoprotein apheresis (LDL-A) in 11 nephrotic children with SR and cyclosporine A (CsA)-resistant primary FSGS.

METHODS

Based on entry criteria, all 11 eligible patients had biopsy-proven primary FSGS presenting with nephrotic syndrome (NS) and were resistant to steroid and conventional-dose CsA therapy. LDL-A was performed twice a week for 3 weeks (first course), then weekly for 6 weeks (second course). Beginning from the second LDL-A course, a dosage of 1 mg/kg/d of prednisone was administered for 6 weeks, then tapered.

RESULTS

Seven patients experienced remission of NS, 5 of whom achieved complete remission within 4 weeks after initiating prednisone therapy with LDL-A. These 5 patients maintained normal renal function during follow-up (median, 4.4 years). Of 2 patients with partial remission, 1 patient maintained stable renal function during follow-up (4.5 years), whereas the other patient showed a gradual decline in renal function and progressed to end-stage renal failure (ESRF) 7.8 years after LDL-A therapy. Four patients who were considered to experience treatment failure had persistent NS and progressed to ESRF in 1.3 years (median) after LDL-A therapy. Complete remission (n = 5) was associated with significantly more highly selective proteinuria compared with treatment failure (n = 4).

CONCLUSION

This study suggests that combined LDL-A and prednisone therapy can be a valuable addition to therapeutic options for treating patients with SR-FSGS. The role of LDL-A in treating these patients deserves to be assessed further in larger randomized controlled trials.