Serum total p-cresol and indoxyl sulfate correlated with stage of chronic kidney disease in renal transplant recipients
Huang, S.-T.; Shu, K.-H.; Cheng, C.-H.; Wu, M.-J.; Yu, T.-M.; Chuang, Y.-W.; Chen, C.-H.
Transplantation Proceedings 44(3): 621-624
Uremic toxins are considered cardiovascular and mortality risk factors in chronic kidney disease (CKD) patients. Both p-cresol and indoxyl sulfate have been shown to induce oxidative stress in vitro and subsequent endothelial dysfunction in uremic patients. Our study evaluated the levels of p-cresol and indoxyl sulfate, and whether they contribute to the progression of CKD in transplant recipients. We retrospectively evaluated 95 patients who had received a transplant from February 1987 to June 2010 in our center; the recipients had a mean transplant duration of 5.3 ± 4.9 years and a mean age of 47.8 ± 14.1 years. Among them, 56.8% (54/95) were male. Patients with glomerular filtration rate (GFR) ≥ 60 mL/min/1.73 m(2) were selected for group 1 (n = 35), and those with GFR < 60 mL/min/1.73 m(2) were selected for group 2 (n = 60). Demographic and clinical data were compared between groups. Serum and urine levels of p-cresol and indoxyl sulfate were also obtained. Baseline serum p-cresol and indoxyl sulfate levels were significantly higher in advanced CKD stages (P = .001 and <.0001, respectively). Patients at advanced CKD stages (group 2) had lower serum levels of hemoglobin and albumin (P < .0001), but higher levels of total cholesterol, triglyceride, and uric acid levels (P = .04, .04 and .001, respectively). Body mass index, C-reactive protein, and serum calcium and phosphate levels showed no significant differences between groups. The cut-off value for serum p-cresol between groups was 1.28 umol/L (P = .01), and that for the indoxyl sulfate level was 0.98 umol/L (P = .0001). The serum p-cresol and indoxyl sulfate levels were significantly higher in advanced CKD stages in transplant recipients. To evaluate the use of serum p-cresol and indoxyl sulfate levels as a predictive tool for survival, larger clinical studies are needed.