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Non-purine selective xanthine oxidase inhibitor ameliorates glomerular endothelial injury in InsAkita diabetic mice. Am J Physiol Renal Physiol 319: F765-F772, 2020. First published September 21, 2020; doi:10.1152/ajprenal.00236.2020.--Endothelial dysfunction represents a predominant early feature of diabetes, rendering patients with diabetes prone to renal complications, e.g., proteinuria. Recent studies have indicated a possible role for xanthine oxidase (XO) in the pathogenesis of vascular dysfunctions associated with diabetes. In the present study, we investigated the contribution of XO activation on the progression of diabetic nephropathy in a mouse model using selective XO inhibitors. Male Ins2Akita heterozygous mice were used with wild-type mice as controls. Akita mice were treated with topiroxostat (Topi) or vehicle for 4 wk. Serum uric acid levels were significantly reduced in Akita + Topi mice compared with Akita + vehicle mice. The Akita + Topi group had a significant reduction in urinary albumin excretion compared with the Akita + vehicle group. Mesangial expansion, glomerular collagen type IV deposition, and glomerular endothelial injury (assessed by lectin staining and transmission electron microscopy) were considerably reduced in the Akita + topi group compared with the Akita + vehicle group. Furthermore, glomerular permeability was significantly higher in the Akita + vehicle group compared with the wild-type group. These changes were reduced with the administration of Topi. We conclude that XO inhibitors preserve glomerular endothelial functions and rescue compromised glomerular permeability, suggesting that XO activation plays a vital role in the pathogenesis of diabetic nephropathy. [ABSTRACT FROM AUTHOR]

The present study aimed to assess the effects of colchicine, a known anti‑inflammatory agent, on renal fibrosis using a murine model of unilateral ureteral obstruction (UUO). Male C57BL/6 mice were divided into two groups, vehicle‑ and colchicine‑treated. Colchicine (0.5 mg/kg/day) was administered by osmotic pump, and the UUO procedure was performed on the left kidney 7 days later. The mice were sacrificed at 14 days following UUO. Colchicine treatment suppressed interstitial fibrosis of the UUO kidneys. In addition, fibrogenic gene expression in the UUO kidneys was decreased by colchicine administration. NRK‑49F normal rat kidney fibroblasts were cultured with or without colchicine under angiotensin II stimulation, following which a wound‑healing assay and actin fiber staining were performed to evaluate the effects of colchicine in vitro. Colchicine was demonstrated to inhibit angiotensin II‑induced fibroblast migration in vitro in a concentration‑dependent manner. Colchicine treatment also suppressed the angiotensin II‑induced activation of Ras homolog gene family member A in NRK‑49F cells. In conclusion, colchicine treatment significantly inhibited fibroblast activity in vitro and attenuated renal fibrosis in vivo in UUO‑operated mice. Therefore, the prevention of renal fibrosis following injury may represent a novel therapeutic application for colchicine. [ABSTRACT FROM AUTHOR]

High levels of aldosterone impair renal function by activating proinflammatory and profibrotic pathways. However, the molecular mechanism underlying aldosterone-induced inflammation and fibrosis is unknown. Inflammasome activation contributes to chronic kidney disease. We hypothesized that aldosterone induces renal tubulointerstitial inflammation and fibrosis by activating the inflammasome. Infusing wild-type mice with aldosterone (0.25 mg/kg/d) caused tubulointerstitial damage, increased expression of inflammasome components, caspase 1 activation, and overproduction of IL-1β and IL-18. These changes were suppressed by eplerenone treatment (100 mg/kg/d) in wild-type mice or in mice deficient in apoptosis-associated speck-like protein with a caspase-recruitment domain (ASC). Caspase 1-positive and F4/80-positive cells colocalized in the interstitium. Bone marrow transplantation using ASC-deficient mice indicated that inflammasome activation in macrophages mediated aldosterone-induced renal fibrosis. IL-18 was detected in culture supernatants of macrophages treated with aldosterone, and mitochondria-derived reactive oxygen species activated the inflammasome in these macrophages. Our results indicate that exposure of macrophages to high levels of aldosterone resulted in the activation of inflammasomes via the mitochondria-derived reactive oxygen species. Thus, inflammasome activation in macrophages may serve as a new therapeutic target for chronic kidney disease. [ABSTRACT FROM AUTHOR]