Análise das interações celulares envolvidas na regeneração do rim após o transplante de células mononucleares de medula óssea em ratos com hipertensão renovascular

Abstract

Chronic kidney disease (CKD) is a public health problem that affects thousands of people around the world. So far, there is no treatment for CKD and the substitutive treatment of renal function such as dialysis or renal transplantation is an available alternative. Therefore, due to the elevated treatment cost and organ shortage stimulates the search for new therapies such as stem cell-therapy. The stem cell-therapy has been highlighted as a potential treatment for chronic diseases like renovascular hypertension. However, a greater understanding of the communication between damaged cells when transplanted stem cells is needed. The aim this study was to evaluate bone marrow mononuclear cell (BMMC) transplantation effects in cellular communication of resident renal cells from renovascular hypertension rats induced by 2kidneys-1clip (2K1C) model. 2K1C rats with renovascular hypertension, induced by left renal artery stenosis, received BMMC from eGFP Lewis rats in the subcapsular region four weeks after clipping. Then, 24 hours, 48 hours, 7 days and 15 days after BMMC transplantation, animals were euthanized, and left kidney was collected. Systolic blood pressure (SBP) was measured weekly and total protein, creatinine and urea levels in plasma and urine samples were evaluated. In addition, morphology, fibrosis and N- and E-cadherin, renin, connexin 40 and nephrin expression were investigated by immunoperoxidase, immunofluorescence and western blotting. The transplanted GFP+ BMMC were quantified by flow cytometry and localized through immunofluorescence. GFP+ BMMC therapy improved renal function of 2K1C animals by normalizing plasma total protein, creatinine and urea levels while reducing proteinuria and leukocyturia and still restored nephrin expression. In addition to renal function, cell therapy led to the reestablishment of renal parenchymal cytoarchitecture with glomeruli and tubules restructuring along with reduction of fibrosis and cellular infiltrate, reflecting clipped and contralateral kidneys sizes smaller discrepancy. N- and E-cadherin expression was restored, accompanied by this morpho functional improvement after GFP+ BMMC transplantation. Connexin 40 expression was also restored whereas reduced renin expression contributing to reduction of SBP. Renin expression was restricted to juxtaglomerular cells after GFP+ BMMC transplantation. We also observed injected GFP+ BMMC were located near the glomeruli and tubules in the renal parenchyma preferably in fibrous regions. In addition, GFP+ BMMC were still found after 15 days of transplantation, seemingly migrating from cortex to medulla over time. Therefore, these data suggest GFP+ BMMC transplantation was able to improve systemic and local effects caused by left renal artery stenosis promoting cell-cell communication restoration in tubular and glomerular segments, accompanied by morphofunctional recovery of 2K1C rats kidney.