The impact of an amino acid-based peritoneal dialysis fluid on plasma total homocysteine levels, lipid profile and body fat mass

Background. The caloric load from glucose-based peritoneal dialysis (PD) fl uids contributes to hypertriglyceridaemia, adiposity and, as result of anor exia, protein malnutrition in PD patients. It has been suggested that repla cement of a glucose-based by an amino acids-based PD fluid (AA-PDF) for one exchange per day might improve the nutritional status and lipid profile. D ue to the uptake of methionine from the dialysate, however, exposure to AA- PDF might aggravate hyper-homocysteinaemia, a frequently occurring risk fac tor for atherosclerosis in uraemic patients. Methods. We studied the impact of a once daily exchange with 1.1% AA-PDF in stead of glucose-based PD fluid for 2 months on plasma methionine and total homocysteine (tHcy) levels, lipid profile, butyrylcholinesterase (BChE) an d body fat mass of seven stable PD patients. Results are expressed as mean +/- SEM. Results. Methionine levels did not increase significantly during therapy, b ut tHcy levels increased substantially from 60 +/- 12 to 84 +/- 19 mu mol/l after 1 month (P = 0.039), and to 85 +/- 22 mu mol/l after 2 months of AA- PDF treatment. Serum triglyceride concentration decreased from 3.0 +/- 0.3 mmol/l at entry to 2.6 +/- 0.5 mmol/l (at 1 month, P = 0.041 vs baseline). Serum BChE also decreased from 6.9 +/- 0.4 U/ml at entry to 6.3 +/- 0.4 U/m l after 2 months (P = 0.014). Total cholesterol concentration and cholester ol fractions did not change. The reduced exposure to glucose-based PD fluid for 2 months resulted in a 0.5 kg reduction in fat mass which was due main ly to a reduction in fat mass of the trunk region (0.3 kg, P = 0.031). Conclusions. It is concluded that methionine-containing AA-PDF induces an i ncrease in the plasma tHcy level. This might, potentially, offset the benef icial effects of an improved serum lipid profile and reduced fat mass on th e risk of cardiovascular disease in PD patients. Lowering the methionine co ntent of the fluid, therefore, may be required to overcome this adverse eff ect.