Frequency of hyperuricemia and effect of calcineurin inhibitors on serum uric acid levels in liver transplanted children

Abstract

Hyperuricemia is common after renal and cardiac transplantations, but it is rarely reported after liver transplantations. The aim of this study is to determine the frequency of hyperuricemia in children following orthotopic liver transplantation and the effects of calcineurin inhibitors tacrolimus and cyclosporine) on blood uric acid levels. Between September 1997 to January 2004, 76 liver transplantations were performed in 70 children (male/female; 39/31) at Ege University, Organ Transplantation Center (37 deceased donation and 39 live donors). Patients who had been transplanted within the last three months and patients who died within six months after liver transplantation were excluded from the study. Finally 59 patients were included in this study. Uric acid levels were measured before transplantation and after transplantation within six months intervals for two yr. In these series 17 cases had increased uric acid levels after liver transplantation (28.8%). Serum uric acid levels in both groups (tacrolimus or cyclosporine) were detected to be significantly higher than initial values at 12th months (p < 0.05). Hyperuricemia developed in eight patients receiving cyclosporine (eight of 11; 72%) whereas nine patients receiving tacrolimus developed hyperuricemia (nine of 48; 18%). However, the rate of having high uric acid levels was significantly higher in cyclosporine group compared tacrolimus group (p = 0.001, OR: 11.5, CI 95% 2.5-52.4). Uric acid levels were also significantly higher in cyclosporine group in 12th and 18th months (respectively, p = 0.003 and p = 0.003). Serum creatinine levels at 12th, 18th and 24th months were significantly higher in cyclosporine group than tacrolimus group (respectively, p = 0.009, p = 0.04 and p = 0.02). Hyperuricemia is a common complication after liver transplantation in children. Cyclosporine may cause hyperuricemia more often in respect to tacrolimus and this may be related to the impairment of renal functions. Complications developing because of hyperuricemia such as gout disease or renal calculi are quite rare in children.

A retrospective study of hyperurecemia in renal transplant recipients

“…But this is in contraindication to another study by Kanby M who found that uric acid level didn't differ significantly between renal transplant recipients receiving cyclosporine and non calcinurin inhibitors 36 . Also during the course of study 15% of normouricemic patients after 1 month of kidney transplant were converted at 6 months to patients having high uric acid level (data not shown).Our finding is consistent with adult kidney transplantation 37,38 and other solid organ transplantation 39,40,41 .…”

Hyperuricemia after liver transplantation in children

“…For Tumgor et al. (17), the prevalence of hyperuricemia was 29% in 70 children followed‐up to two yr. Hyperuricemia in pediatric liver transplantation may be multifactorial but we found age at OLT was the only significant predictor. Older age is a risk factor for developing hyperuricemia: 50% of the patients >10 yr at transplantation had elevated uric acid levels, a similar prevalence than reported previously in adult studies (14).…”

Risk Factors for Cyclosporin A Nephrotoxicity in Children with Steroid-Dependant Nephrotic Syndrome

“…CsA is known to cause hyperuricemia in children with renal transplantation by limiting their renal tubular excretion of uric acid (28). In children who have received a liver transplant, this effect has been shown to be more frequent with CsA-than FK506-based immunosuppression regimens (29). Conversely, hyperuricemia can be associated with hypertension, chronic tubulointerstitial renal lesions, afferent arteriolopathy, and increased renal vascular resistance, raising the hypothesis that hyperuricemia is a cofactor in salt-sensitive hypertension and may exacerbate CsAinduced nephropathy (30).…”