Autografting of Renal Progenitor Cells Ameliorates Kidney Damage in Experimental Model of Pyelonephritis

Abstract

Current therapies for pyelonephritic renal damage have severe limitations; stem cells may offer an exciting potential in regenerating nephrology. We aimed to investigate the feasibility of direct intrarenal injection of autologous renal progenitor cells (RPCs; originated from epithelial cells in Bowman's capsule) in chronic pyelonephritis rat model. Twenty-seven rats were divided into three groups. The control group (GI, n = 3) underwent sham subcapsular injection of isotonic saline. Pyelonephritis was induced in the right kidney of the remaining 24 rats and isotonic saline (GII, n = 12) or labeled autologous RPCs, obtained from a biopsy of left kidney (GIII, n = 12), were injected into the subcapsular space 6 weeks later. At 7, 14, 28, and 60 days, dimercaptosuccinic acid scan was performed in three animals of each group at every interval and subsequently renal sections were obtained for the evaluation of tubular and glomerular regeneration and proliferation. Cell transplantation resulted in the reduction of tubular and glomerular atrophy after 2 weeks. The transplanted cells were observed in the reconstructed region of the kidneys as evidenced by the presence of fluorescently labeled cells both in tubules and glomeruli. We also observed significant decrease in interstitial fibrosis in the fourth week and there were higher amount of Ki-67-positive cells in GIII. Notably, the right renal tissue integrity was significantly improved in this group and revealed normal cortical function on day 60. Transplanting RPCs showed the potential for partial augmentation of kidney structure and function in pyelonephritis. Cellular repair was seen predominantly in the proximal tubule, the major site of injury in pyelonephritis. Our findings may pave the way toward the future regeneration of renal scarring of pyelonephritis in children.