Clinical journal of the American Society of Nephrology : CJASN

Diabetic kidney disease develops in approximately 40% of patients who are diabetic and is the leading cause of CKD worldwide. Although ESRD may be the most recognizable consequence of diabetic kidney disease, the majority of patients actually die from cardiovascular diseases and infections before needing kidney replacement therapy. The natural history of diabetic kidney disease includes glomerular hyperfiltration, progressive albuminuria, declining GFR, and ultimately, ESRD. Metabolic changes associated with diabetes lead to glomerular hypertrophy, glomerulosclerosis, and tubulointerstitial inflammation and fibrosis. Despite current therapies, there is large residual risk of diabetic kidney disease onset and progression. Therefore, widespread innovation is urgently needed to improve health outcomes for patients with diabetic kidney disease. Achieving this goal will require characterization of new biomarkers, designing clinical trials that evaluate clinically pertinent end points, and development of therapeutic agents targeting kidney-specific disease mechanisms (e.g., glomerular hyperfiltration, inflammation, and fibrosis). Additionally, greater attention to dissemination and implementation of best practices is needed in both clinical and community settings.Introduction

Membranous nephropathy (MN) is a unique glomerular lesion that is the most common cause of idiopathic nephrotic syndrome in nondiabetic white adults. About 80% of cases are renal limited (primary MN, PMN) and 20% are associated with other systemic diseases or exposures (secondary MN). This review focuses only on PMN. Most cases of PMN have circulating IgG4 autoantibody to the podocyte membrane antigen PLA2R (70%), biopsy evidence PLA2R staining indicating recent immunologic disease activity despite negative serum antibody levels (15%), or serum anti-THSD7A (3%–5%). The remaining 10% without demonstrable anti-PLA2R/THSd7A antibody or antigen likely have PMN probably secondary to a different, still unidentified, anti-podocyte antibody. Considerable clinical and experimental data now suggests these antibodies are pathogenic. Clinically, 80% of patients with PMN present with nephrotic syndrome and 20% with non-nephrotic proteinuria. Untreated, about one third undergo spontaneous remission, especially those with absent or low anti-PLA2R levels, one-third progress to ESRD over 10 years, and the remainder develop nonprogressive CKD. Proteinuria can persist for months after circulating anti-PLA2R/THSD7A antibody is no longer detectable (immunologic remission). All patients with PMN should be treated with supportive care from the time of diagnosis to minimize protein excretion. Patients with elevated anti-PLA2R/THSD7A levels and proteinuria >3.5 g/d at diagnosis, and those who fail to reduce proteinuria to <3.5 g after 6 months of supportive care or have complications of nephrotic syndrome, should be considered for immunosuppressive therapy. Accepted regimens include steroids/cyclophosphamide, calcineurin inhibitors, and B cell depletion. With proper management, only 10% or less will develop ESRD over the subsequent 10 years.