Abstract 233: Resistance Training Attenuates Renal Dysfunction in Animal Diabetic Nephropathy but Does Not Restore Kidney ACE/ACE2 Balance

Abstract

Overactivity of the intrarenal renin-angiotensin system (RAS) has been implicated in the pathogenesis of diabetic nephropathy. Our group has already demonstrated that aerobic exercise reduces kidney angiotensin II levels and attenuates renal dysfunction under concurrence of diabetes and hypertension. Resistance training (RT) has recently been recognized as a useful therapeutic tool for the treatment chronic diseases and similar to aerobic exercise, has been reported to improve glycemic control. Therefore, the aim of this study was to evaluate the effect of RT on renal function and RAS in diabetic animals, to understand whether this type of exercise is also associated with renoprotection. Wistar rats (3 months old) were randomized into: sedentary control (SC); trained control (TC); sedentary diabetic (SD) and trained diabetic (TD). Animals were made diabetic with a single tail injection of streptozotocin (STZ, 50 mg/Kg). RT was performed on an 110-cm ladder (8 ladder climbs, once/day, 5 days/week, 8 weeks), carrying a load of 50-80% body weight (BW) appended to the tail. At week 8, 24 hr urine volume and albuminuria were evaluated. Kidney was excised and ACE and ACE2 activities were determined (ZPhe-HL and 7-Mca-APK(Dnp), respectively) (Two way ANOVA + Tukey test; P<0.05). RT significantly reduced blood glucose (TD = 449 ± 17 vs. SD = 572 ± 18 mg/dL) and attenuated BW loss of diabetic animals. DM reduced renal ACE activity in sedentary and trained groups (SD = 3.72 ± 0.48, TD = 3.85 ± 0.40 vs. SC = 9.2 ± 0.59 nmol/min/mg), while RT reduced enzyme activity only in control group (TC = 5.14 ± 0.26 vs. SC = 9.2 ± 0.59 nmol/min/mg). RT reduced renal ACE2 in the control group compared to the others (TC = 0.05 ± 0.0001 vs. SC = 0.09 ± 0.004, SD = 0.09 ± 0.003, TD = 0.10 ± 0.002 μM/min/mg), with no effect of diabetes on enzyme activity. RT improved renal function, decreasing urinary volume and albuminuria (DT = 4.13 ± 0.84 vs. SD = 11 ± 2.11 mg/24h) in DT group. The results from the present study show that RT is strongly associated with renoprotection in an experimental model of diabetic nephropathy. Moreover, results show that this improvement on renal function is modulated by other pathways apart from ACE and ACE2 converting enzymes. Financial Support: FAPESP, CAPES, CNPq.

Resistance Training Improved the Kidney Function of Type 2 Diabetic Patients with the Risk of Nephropathy: A Randomized Control Trial

“…Accordingly, by a simple analogy between the results of the CG and RTG, it can be logically concluded that RT, though it did not improve kidney function, at least stopped the development of kidney dysfunction and prevented eGFR from decreasing in the RTG, whereas the kidney function of the CG probably deteriorated due to the lack of RT, resulting in the increased levels of IGFBP-3. This justification can be supported by the report of Santos et al who showed that RT could attenuate renal dysfunction in animal DN after an 8-week training period (31). However, it seems that the improvement of kidney function relies on various sophisticated physiological adaptations, requiring the long-term intervention of proper exercise therapy; otherwise, significant improvement can be barely observed through short-term training programs.…”