Abstract P394: Ace Activity and Its Expression as a Hypertension Biomarker in the Urine of Pediatric Renal Transplant Recipients

Abstract

Pediatric hypertension is a risk factor for hypertension in adults. Primary hypertension results from genetic, environmental, and behavioral factors. Renin Angiotensin System is important to control cardiovascular and renal functions. Angiotensin Converting Enzyme (ACE) has isoforms: somatic (130-190 kDa) and testicular (90-110 kDa). Casarini et al. described the N-domain isoform of 90kDa, in urine of hypertensive humans as a possible hypertension biomarker. Objective: Analyze ACE isoform in urine of pediatric renal transplant recipients before and after transplantation and urine of donor, to verify the 90 kDa isoform transmission and correlating with hypertension. Methods: 30 pediatric recipients with living donors; ACE activity was performed before, 1, 3 and 6 months post transplantation using ZPhe and HHL as substrates and its ratio. Results: 69% had pre-transplant hypertension and 85.7% family history. After 6 months 25% remained. From the pre-transplant until the sixth month after, ACE activity was reduced. In the model of linear regression between ACE activity and variables, including pre-transplantation for the substrates ZPhe-HL remained significant, time and uropathy (0.023 more); with HHL, time and uropathy with higher activity of ACE (0.019 more) and for weight, reduction of ACE activity ( 0.00038 at 1 kg increase in weight). At post-transplant only time and weight remained significant with ZPhe-HL, and for HHL uropathy, proteinuria (0.010 more ACE activity) and weight. Recipients before transplantation had higher urinary ACE activity when compared to controls. Western blotting data showed that all recipients without ACE 90KDa when received a kidney from the donor that had this isoform, started to express it. Conclusions: Increased ACE activity in uropathies may be associated with renal injury or intra-renal production. Proteinuria, a marker of renal injury, can be associated with increase on ACE activity. With nutritional recovery and a healthy kidney after transplantation, patients can reverse the degree of renal damage and decrease the production of ACE.