To study the clinical course and the predictors of outcome in children and adolescents, 39 patients with nephrotic syndrome and primary focal segmental glomerulosclerosis (FSGS) were followed for a mean of 84.6 months. Thirty-six patients were treated with prednisone, either alone or in conjunction with cyclophosphamide. The clinical course was one of sustained remission in 4 patients, frequent relapse in 13, persistent nonnephrotic proteinuria in 5, and persistent nephrotic syndrome in 17; 2 patients had stable renal failure and 8 had progressive renal failure, 5 of them evolving to end-stage renal failure (ESRF). Resistance to prednisone was recorded in 76.6% of patients. The use of cyclophosphamide plus prednisone was of benefit in 42.8% of patients; 22.2% of the prednisone-resistant patients achieved remission of the nephrotic syndrome. A Kaplan-Meier analysis revealed a survival rate of 92% after 5 years, 86% after 10 years, and 76% after 15 years. Using both univariate and multivariate analysis, persistent nephrotic syndrome was associated with progression to ESRF and the remission of proteinuria with maintenance of renal function. As the outcome of the nephrotic syndrome in FSGS is significantly improved by remission of proteinuria, it is conceivable that immunosuppressive medication may be used in conjunction with prednisone in patients with steroid resistance.

Ischemia is an important cause of acute kidney injury (AKI). Pentoxifylline has been shown to improve tissue oxygenation and endothelial function and inhibit proinflammatory cytokine production. The aim of this study was to evaluate a possible renal protective effect of pentoxifylline against ischemia by measuring mitochondrial respiratory metabolism as an index of cell damage. Rats were submitted to right nephrectomy. The left kidney was submitted to ischemia by clamping the renal artery for 45 minutes. Immediately after release of the clamp, 1 mL of a solution containing 20 mg of pentoxifylline/mL was injected intravenously, while a control group received 1 mL of normal saline intravenously. Five minutes after the injection, the left kidney was removed, homogenized, and subjected to refrigerated differential centrifugation. Mitochondrial respiratory metabolism was measured polarographically. The mitochondria isolated from the kidneys of saline-treated rats had an endogenous respiration of 9.20 ± 1.0 hmol O 2 /mg protein/min compared to 8.9 ± 1.4 hmol O 2 /mg protein/min in the pentoxifylline-treated rats (p > 0.05). When stimulated by sodium succinate, the respiratory metabolism increased in a similar fashion in both groups of animals: 17.9 ± 2.3 and 18.1 ± 2.1hmol O 2 /mg protein/min in the untreated and pentoxifylline-treated groups, respectively (p > 0.05). In the present study, pentoxifylline was not found to exert any protective effect on the kidney. It is possible that at the time of pentoxifylline administration, the mitochondria had already been damaged by the process of ischemia, and its effect may have been insufficient to reverse cell damage.

Prednisone is the initial treatment of primary focal segmental glomerulosclerosis. However, when immunosuppressive agents in combination with steroids are used in the treatment of prednisone-dependent and prednisone-resistant patients the remission rate is variable. We report a long-term trial using cyclophosphamide (2.0 to 3.0 mg/kg body weight for 12 weeks) in combination with prednisone (1.0 to 2.0 mg/kg body weight), as compared with prednisone alone for the treatment of prednisone-resistant and frequently relapsing nephrotic syndrome and focal segmental glomerulosclerosis. Fifty-four patients (34 males and 20 females) with a diagnosis of idiopathic nephrotic syndrome and focal segmental glomerulosclerosis, followed-up for an average of 86.1 ± 82.4 months, were evaluated. Complete remission occurred in 20.4% and partial remission in 14.8% of the patients treated with steroids and in 26.7 and 20.0% of the patients treated with cyclophosphamide + prednisone, respectively. Of the 24 prednisoneresistant patients treated with steroids in combination with cyclophosphamide, 33.3% obtained a complete/partial response. At the time of final evaluation, 25% of the patients treated with prednisone and 10.0% of those treated with prednisone in combination with cyclophosphamide had reached end-stage renal disease. Persistent nephrotic syndrome and progressive renal insufficiency were more frequently observed among the patients treated with prednisone alone (50.0 vs 33.3% and 33.3 vs 16.7%, respectively). The treatments were well tolerated and no patient experienced adverse reactions requiring discontinuation of medications. Although open-label and non-randomized, the present trial showed that cyclophosphamide is a reasonable choice for the treatment of primary focal segmental glomerulosclerosis and prednisone-resistant nephrotic syndrome.