林俊廷^1,3、曾一修^1,2

亞東紀念醫院 外科部 ¹創傷科，²泌尿科; ³醫學研究部

 Jun-Ting Lin^1,3, Yi-Shiou Tseng^1,2

Divisions of Traumatology¹ and Urology², Department of Surgery, Far Eastern Memorial Hospital, New Taipei City, Taiwan

Department of Medical Research³, Far Eastern Memorial Hospital, New Taipei City, Taiwan

 

Purpose: The process of kidney stone formation involves crystal nucleation, growth, aggregation and adhesion. Previous literature found that hyperoxaluria requires TNF receptors to initiate crystal adhesion and TNF receptor inhibitor can partially prevent kidney stone formation. Therefore, TNF-α inhibitor may be used to treat hyperoxaluric kidney stone disease. The aim of our research was to study the influence of TNF-α inhibitor on calcium oxalate crystal formation and adhesion protein expression of hyperoxaluria rat kidney.

Materials and Methods: We established a hyperoxaluria Sprague Dawley rat model by intraperitoneal injection of glyoxylate (60mg/kg) for seven days. Adalimumab is a human monoclonal antibody IgG1 that antagonizes the action of TNF-α. The treatment group (n=6) was given one dose of Adalimumab (50mg/kg) on the first day with 7 days of glyoxylate, and a positive control group (n=6) was given R-7050 (12 mg/kg), a kind of TNF receptor inhibitor, for every alternate day with 7 days of glyoxylate. Another two groups were placebo (n=6) and glyoxylate group (n=6). 24-hour urine were collected while rats were in metabolic cages. Blood and kidneys were obtained under anesthesia. Biochemical values of blood and urine were examined. Immunohistochemistry (IHC) analysis and western blot were used to measure the expression of TNF receptors, Annexin II and Osteopontin (OPN) in the kidneys.

Results: Plasma blood urea nitrogen (BUN) and creatinine (Cre) were not different between four groups. In urine, microscopy showed that the amount of crystallization of the glyoxylate group higher than the placebo group. However, the amount of urine crystallization was reduced in Adalimumab and R7050 groups. Elevated urine TNF-α levels were found in the glyoxylate group (19.9±5.), and urine TNF-α levels were decreased in Adalimumab (8.8±2.1) and R7050 (3.1±3.4) groups. In kidney tissue, polarized light microscopy showed that there were more crystals in the glyoxylate group than the placebo group. However, the Adalimumab and R7050 reduced the amount of kidney crystals. IHC analysis showed less adhesion proteins Annexin II and OPN in the kidneys of Adalimumab and R7050 groups than glyoxylate group. Annexin II, OPN were quantified by western blot which revealed lower expression in the Adalimumab and R7050 groups.

Conclusions: Hyperoxaluria increases the urine TNF-α levels and the expression of crystal adhesion proteins Annexin II and OPN in the kidney that induces kidney stone formation. Administration of  TNF-α inhibitor and TNF receptor inhibitor for hyperoxaluria rat can reduce the expression of Annexin II, OPN and crystal formation in the kidneys. Adalimumab, a clinically used TNF-α inhibitor, may be applied to treat hyperoxaluric kidney stone disease.