Brown adipocytes and β3-stimulant-induced brown-like adipocytes contribute to the prevention of renal crystal formation.

Abstract

According to recent studies, kidney stones are associated with metabolic syndrome. We focused on brown adipocytes and β3-stimulant-induced brown-like adipocytes to investigate how these adipocytes influence kidney stone disease. For the interscapular brown adipose tissue (iBAT) removal experiment, mice were subjected to either iBAT removal or sham operation (X-BAT group or sham group), and, after 3 wk, renal crystal deposition was induced by intra-abdominal injection of glyoxylate (GOX) for 6 days. For the β3-stimulant experiment, mice were administered intra-abdominal injections of the β3-stimulant (β3-group) or saline (control group) for 6 days. Thereafter, renal crystal deposition was induced by intra-abdominal injection of GOX for 6 days. iBAT removal decreased the expression of Sod1 and increased that of chemokine (C-C motif) ligand 2 (Ccl2), EGF module-containing mucin-like receptor 1 (Emr1), and tumor necrosis factor (Tnf) in the kidneys. Renal crystal deposition was 2.06-fold higher in the X-BAT group than in the sham group. The β3-stimulant caused differentiation of white adipocytes into brown-like adipocytes. In the kidneys of the β3-group, the expression of Ccl2 and Emr1 decreased and that of Sod1 increased. Renal crystal deposition was 0.17-fold lower in the β3-group than in the control group. In summary, iBAT removal promoted kidney inflammation and renal crystal formation. β3-Stimulant-induced brown-like adipocytes reduced inflammation and improved antioxidant action in the kidneys, which suppressed renal crystal formation. This is the first report on the therapeutic role of brown and brown-like adipocytes for kidney stone formation.