Clinical and histopathological features of acute kidney injury in adult-onset minimal change nephrotic syndrome

Efficacy and safety of rituximab for primary nephrotic syndrome with acute kidney injury: A two-center prospective cohort study

The purpose of this study was to investigate the efficacy and safety of a low-dose Rituximab (RTX) regimen driven by peripheral blood B lymphocyte count in the treatment of adult patients with nephrotic syndrome (NS) complicated with acute kidney disease (AKI). We conducted a prospective single-arm study to evaluate the effect of B cells-driven RTX regimen. Patients with NS (MCD, FSGS, MN, IgAN) complicated with AKI fulfilling the inclusion criteria were eligible for this study. Patients were followed up at intervals of 2 months. Student's t-test and Chi-squared test were used to analyze normally distributed continuous variables and non-normally distributed continuous variables, respectively. From August 2018 to January 2022, 23 patients met the inclusion criteria and agreed to participate in the study. 3, 9, and 11 patients were AKI stage 1, 2, and 3, respectively. From baseline to the latest follow-up, 20 patients had complete and partial recovery of renal function. Accompanied by depletion of B cells, significant reduction of urinary protein excretion, serum total cholesterol, and the number of relapses were observed during the 12 months after the first RTX infusion as compared with during the 12 months before RTX injection. The number of patients who maintained steroids and immunosuppressive medications also remarkably decreased. This study indicates that the targets-driven treatment of low-dose RTX can achieve a high remission rate and alleviate the loss of kidney function in treating NS with AKI. The long-term efficacy, side effects, and therapeutic economics of RTX are reasonable.

Acute Kidney Injury Caused by Renin-Angiotensin System Inhibitors During Minimal Change Disease Treatment

A 76-year-old Japanese man with nephrotic syndrome was admitted to our department for treatment. After his admission, he was administered prednisolone (PSL) at 40 mg/day, and a percutaneous renal biopsy was performed. However, on the first day of admission, his urinary protein decreased from 5.05 g/gCr to 1.85 g/gCr. On the fourth day of admission, his urinary protein further decreased to 0.38 g/gCr and the patient developed acute kidney injury (AKI). Renin-angiotensin system (RAS) inhibitors were suspected to be the cause of AKI; therefore, they were discontinued. After the renal function improved, the urinary protein worsened again to 5.49 g/gCr. Renal pathology suggested minimal change disease (MCD); therefore, PSL was continued. The patient's urinary protein subsequently improved and he had no renal function impairment. Minimal change disease can be complicated by AKI through intravascular volume depletion caused by high urinary protein and hypoalbuminemia. However, when MCD is complicated by RAS inhibitor-associated AKI, the urinary protein may notably decrease, and the patient may present with an atypical course of MCD-associated AKI.

Clinical and histopathological features related to time to complete remission in adult-onset minimal change nephrotic syndrome patients with corticosteroid treatment

BACKGROUND

Minimal change nephrotic syndrome (MCNS) is a common type of nephrotic syndrome in adults, though evidence regarding its clinical and histopathological features related to time to complete remission (CR) is limited.

METHODS

This was a retrospective study of biopsy-proven, first-onset, adult MCNS patients who achieved CR after undergoing corticosteroid treatment. Body weight (BW) change rate was calculated as follows: (BW at admission - BW at discharge)/BW at discharge × 100. Histopathological examinations were performed, with particular attention given to tubulointerstitial lesions.

RESULTS

Fifty-seven patients (median 41 years old, range 22-63 years; 37 males) were diagnosed with MCNS from 2007 to 2020. Time to CR was a median 11 (8-21) days. In addition to serum creatinine and urinary protein, BW change rate also showed a positive correlation with time to CR (r_s = 0.438, p < 0.001; r_s = 0.280, p = 0.035; r_s = 0.544, p < 0.001; respectively), while multivariate Cox proportional hazards models also revealed those factors as significant predictors for longer time to CR. In MCNS patients with a higher BW change rate (n = 28), serum creatinine, urinary protein, histopathological score, and time to CR were significantly greater as compared to those with a lower BW change rate (n =29). Also, in those patients, histopathological interstitial edema was significantly associated with longer time to CR after adjustments for serum creatinine and urinary protein.

CONCLUSION

The present results indicate that BW change rate can predict time to CR in adult-onset MCNS patients. Histopathologically, interstitial edema is also an important factor for time to CR in MCNS patients with greater BW increase.