P0685RENAL SUBCAPSULAR ADIPOSE-DERIVED MESENCHYMAL STEM CELLS (ASC) ADMINISTRATION, ASSOCIATED TO LOSARTAN TREATMENT, PREVENTED THE PROGRESSION OF RENAL DAMAGE IN AN EXPERIMENTAL MODEL OF CHRONIC KIDNEY DISEASE (CKD)

Abstract

Abstract INTRODUCTION / AIMS Chronic kidney disease (CKD) is considered a public health problem with epidemic proportions worldwide. Overactivity of the renin-angiotensin-aldosterone system (RAAS), associated to the establishment of a chronic self-sustained renal inflammation, are the main factors which contribute to the progression of CKD, leading to tissue fibrosis and loss of function. Consequently, RAAS inhibitors, such as the AT-1 receptor antagonist, Losartan, are among the most currently employed therapeutic strategies to slow down CKD progression, although the renoprotection afforded by these drugs is not complete. The association of anti-inflammatory and immunosuppressive drugs to RAAS inhibition is limited to the treatment of specific nephropathies, and its safety is still not entirely known. In this context, experimental application of mesenchymal stem cells (mSC) as a treatment to control renal inflammation and fibrosis have been showing promising results in studies with animal models of CKD. The aim of the present study was to analyze the renoprotective effects of subcapsular application of adipose-tissue derived mSC (ASC), associated to Losartan treatment, in rats submitted to 5/6 nephrectomy, after the establishment of CKD. METHODS ASC were isolated from gonadal adipose tissue from male Wistar rats, cultured until P4 and characterized by flow cytometry and in vitro differentiation. Male Wistar rats underwent 5/6 nephrectomy and were followed for 15 days to confirm the establishment of the nephropathy (CKD 15d). After this period, animals underwent a new surgery in which they received a subcapsular injection of 10 μL of sterile PBS (vehicle), or 2x106 ASC diluted in 10 μL of sterile PBS. Part of these animals were than treated orally with 50 mg/kg/day of Losartan (LOS) for further 15 days (groups CKD + LOS 30d and CKD + LOS + ASC 30d). A group of animals that received only subcapsular vehicle were kept untreated for the same period (CKD 30d). Sham-operated rats, euthanized at days 15 (Sham 15d) and 30 (Sham 30d), were used as controls. Survival rate, body weight (BW), systolic blood pressure (BP), 24h urinary protein (24h UPE) and albumin (24h UAE) excretion, serum creatinine (SCr) and blood urea nitrogen (BUN) concentrations, percentage (GS%) and index (GSI) of glomerulosclerosis, percentage of tubulointerstitial fibrosis (INT%) and renal infiltration by macrophages (CD68) were assessed 15 and 30 days after 5/6 nephrectomy. The obtained results are presented as Mean ± SE. Differences among groups were analyzed by one-way ANOVA. RESULTS The renal subcapsular application of ASC after the establishment of severe CKD improved the renoprotection obtained with the classic treatment with LOS. The association of LOS + ASC significantly improved animal’s survival, reduced blood pressure, proteinuria and albuminuria, prevented the development of glomerular structural damage and interstitial fibrosis, and inhibited renal inflammation by normalizing renal macrophage infiltration in the CKD + LOS + ASC group. CONCLUSIONS Our preliminary results demonstrate that the application of ASC, associated to the oral administration of LOS exerted additional renoprotection in the 5/6 renal ablation model, compared to LOS monotherapy. These findings suggest that ASC therapy could be employed as a therapeutic additive together with the traditional RAAS blockade, to detain the progression of CKD.