Células-tronco mesenquimais do tecido adiposo no reparo de alterações renais induzidas por isquemia renal e envenenamento crotálico

Abstract

Crotalus durissus terrificus envenomation may lead to acute renal insufficiency or failure (ARF) characterized by 100% hyperuricemia and 60% hypercreatininemia, as well as oxidative stress in the renal cortex and medulla. In turn, ischemia is known to decrease the supply of oxygen and nutrients and when occurs in the renal tissue it can generate ARF. Mesenchymal stem cells (MSCs) from adipose tissue are genetically and morphologically very stable under cell culture conditions. Furthermore, MSCs have low senescence and high proliferative capacity and immunomodulatory properties, as well as certain efficacy in the treatment of experimental ischemia-induced ARF. The present study evaluated the hypothesis that MSCs therapy could be efficient on renal sequelae in mice that survive to ARF associated with the experimental model of hyperuricemia induced by C. d. terrificus venom (vCdt), compared to ARF associated with bilateral ischemia induced by renal pedicle clamping. MSCs were isolated from mouse adipose tissue. The immunophenotyping of MSCs was performed using cell surface markers CD13, CD29, CD44, CD90, CD105; CD31, CD34 and CD45, as well as by differentiation assay (adipocyte, osteocyte and chondrocyte). Renal function (uric acid, creatinine, urea and protein in plasma and urine) and oxidative stress (reduced glutathione, oxidized glutathione and malondialdehyde in the cortex and renal medulla) were measured at intervals over 96 h, or up to 7 days if amelioration or restoration did not occur in 96 h, in healthy control mice and in mice envenomed with 80%LD50 vCdt i.p (vCdt), or subjected to bilateral ischemia (Isq bil), and in these same animal groups treated with 105 MSCs / 0.2 mL / animal, administered in the tail vein, for 3 consecutive days at 24 h intervals following the PBS administration procedure in the control animals, or ARF induction in the others. The vCdt induced higher and more premature lethality than bilateral Isq, which is attributable to hyperuricemia in vCdt, that is a differential factor of this ARF model in relation to Isq bil model. This lethality was restricted to 24 h and 72 h, respectively in vCdt and Isq bil, with no subsequent occurrences. The sequelae of bilateral ischemic ARF induction in the survivors after 48 h of induction were severe hypercreatinemia, hyperuremia and hypercreatinuria, as well as oxidative stress. The sequelae of the induction of ARF by vCdt in the survivors after 48 h of induction were severe hypercreatinemia, mild hyperuricosuria and hypercreatinuria, as well as oxidative stress. After 96 h of ARF induction, the treatment with MSCs restored uremia and oxidative stress in the ischemic mice, as well as restored oxidative stress, creatinemia and creatinuria in the envenomed mice. The sequelae of bilateral ischemic ARF in survivors after 7 days of induction, considered in the present study as a maximum period for the manifestation of any therapeutic effect of MSCs with sufficient interest for the consolidation of renal function after ARF, were mild glomerular degeneration and proliferation, as well as the presence of cellular infiltrate and severe tubular degeneration and necrosis, in addition to severe hypercreatinemia. The sequelae of the induction of ARF by vCdt in survivors after 7 days of induction were mild glomerular degeneration and proliferation, as well as moderate tubular degeneration. After 7 days of induction of ARF, the treatment with MSCs ameliorated the level of glomerular and tubular degeneration and necrosis in the envenomed animals, as well as ameliorated creatinemia and the level of inflammatory infiltration in ischemic animals. This potential therapeutic efficacy of MSCs in the sequelae of ARF induced by crotalic envenomation offers a new perspective for the clinical approach of hyperuricemic ARF, as well as suggests the importance of future studies on indirect and / or direct mechanisms of MSCs action in this type of ARF and on the effect of early administration of MSCs on the lethality of ARF in general.