title: Serum total p-cresol and indoxyl sulfate correlated with stage of chronic kidney disease in renal transplant recipients.
abstract: BACKGROUND
  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.
  
  
  METHODS
  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.
  
  
  RESULTS
  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).
  
  
  CONCLUSIONS
  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.
authors.affiliation: Division of Nephrology, Department of Internal Medicine, Taichung Veterans General Hospital, Taichung, Taiwan.
authors.forename: S-T
authors.initials: ST
authors.lastname: Huang
authors.forename: K-H
authors.initials: KH
authors.lastname: Shu
authors.forename: C-H
authors.initials: CH
authors.lastname: Cheng
authors.forename: M-J
authors.initials: MJ
authors.lastname: Wu
authors.forename: T-M
authors.initials: TM
authors.lastname: Yu
authors.forename: Y-W
authors.initials: YW
authors.lastname: Chuang
authors.forename: C-H
authors.initials: CH
authors.lastname: Chen
mesh_terms: D000328:Adult; D003408:Cresols / Q000097:blood*; D018450:Disease Progression; D005260:Female; D006801:Humans; D007200:Indican / Q000097:blood*; D007676:Kidney Failure, Chronic / Q000097:blood* / Q000473:pathology / Q000601:surgery; D016030:Kidney Transplantation; D008297:Male
chemical_list: D003408:Cresols; C032538:4-cresol; D007200:Indican