title: Factors associated with increased plasma homocysteine in patients using an amino acid peritoneal dialysis fluid.
abstract: BACKGROUND
  Although amino acid peritoneal dialysate (AAPD) substitution is thought to improve protein-energy malnutrition in patients undergoing peritoneal dialysis (PD), it may also increase plasma homocysteine (Hcy) levels due to the methionine load in the dialysate. However, it is still unclear which factors are important for elevating Hcy in patients treated with AAPD.
  
  
  METHODS
  Sixteen malnourished PD patients (age 48+/-18 years) were treated daily with one exchange of 1.1% AAPD for 3 months. The effects of AAPD on nutrition, Hcy, methionine, leptin and insulin resistance were studied. We also analysed factors that influenced plasma Hcy levels.
  
  
  RESULTS
  We found a transient increase in serum albumin (P<0.01) after 1 month treatment, especially in patients with serum albumin < or = 3.5 g/dl. Total plasma Hcy increased markedly after AAPD (the peak at month 2, P<0.001) and returned to baseline after ceasing AAPD, despite no changes in dietary methionine intake and serum methionine levels. Eight patients with Hcy increments >5.65 microM (the median) had lesser dietary intakes of protein (P = 0.01) and methionine (P = 0.028), lower body fat mass (P = 0.05) and lower aspartate transaminase (AST) (P = 0.008) before AAPD treatment than patients with lower increments. DeltaHcy was inversely correlated with baseline dietary methionine intake (r = -0.61), protein intake (r = -0.54) and AST (r = -0.51) (all P<0.05). There was no change in leptin or insulin resistance. AAPD treatment significantly increased Kt/Vurea (P<0.001), weekly creatinine clearance (P<0.05) and peritoneal glucose transport (P<0.05).
  
  
  CONCLUSIONS
  Treatment with 1.1% AAPD transiently increased serum albumin in malnourished PD patients. However, the methionine load from the dialysate in this study significantly elevated plasma Hcy levels, especially in patients with lower protein and methionine intakes, and lower AST levels. Further long-term studies will be needed to clarify potential nutritional benefits and adverse effects of AAPD.
authors.affiliation: Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan.
authors.forename: Shao-Yu
authors.initials: SY
authors.lastname: Yang
authors.forename: Jenq-Wen
authors.initials: JW
authors.lastname: Huang
authors.forename: Kai-Yao
authors.initials: KY
authors.lastname: Shih
authors.forename: Shih-Ping
authors.initials: SP
authors.lastname: Hsu
authors.forename: Pei-Lun
authors.initials: PL
authors.lastname: Chu
authors.forename: Tzong-Shinn
authors.initials: TS
authors.lastname: Chu
authors.forename: Kwan-Dun
authors.initials: KD
authors.lastname: Wu
mesh_terms: D000328:Adult; D000596:Amino Acids / Q000009:adverse effects*; D015314:Dialysis Solutions / Q000009:adverse effects* / Q000737:chemistry; D005260:Female; D005500:Follow-Up Studies; D006710:Homocysteine / Q000097:blood / Q000378:metabolism*; D006801:Humans; D020138:Hyperhomocysteinemia / Q000175:diagnosis* / Q000209:etiology; D007676:Kidney Failure, Chronic / Q000175:diagnosis / Q000628:therapy*; D007677:Kidney Function Tests; D008297:Male; D044342:Malnutrition / Q000503:physiopathology; D008875:Middle Aged; D010530:Peritoneal Dialysis / Q000009:adverse effects* / Q000379:methods; D011336:Probability; D011446:Prospective Studies; D018570:Risk Assessment; D012720:Severity of Illness Index; D016037:Single-Blind Method; D018709:Statistics, Nonparametric; D013624:Taiwan; D016896:Treatment Outcome
chemical_list: D000596:Amino Acids; D015314:Dialysis Solutions; D006710:Homocysteine