Association of serum L-kynurenine with nutritional status and vascular stiffness in maintenance hemodialysis patients / 中华肾脏病杂志

ABSTRACT

Objective To study the association of serum L-kynurenine changes with nutritional status and vascular stiffness in maintenance hemodialysis (MHD) patients. Methods Twenty gender- and age-matched healthy volunteers (healthy group) and 40 MHD patients,including 20 cases with α-keto aicd(α-keto acid group)and 20 cases without α-keto aicd(non-α-keto acid group)were enrolled in the study.Serum L-kynurenine was measured by high performance liquid chromatography.C-reactive protein (CRP)and interleukin 6 (IL-6)were detected.Subjective global assessment(SGA)and malnutrition inflammation score(MIS)were applied to evaluate the nutritional status.Pulse wave velocity(PWV)was used to evaluate arterial stiffness for both groups of MHD patients. Results Serum L-kynurenine was significantly higher in MHD patients than that in healthy subjects[(3.20±1.12)μmol/L vs (1.74±0.27)μmol/L,P0.05].IL-6 was significantly higher in MHD patients as compared to healthy subjects[(6.45±3.78)ng/L vs(1.38±1.59)ng/L,P<0.01],while such difference was found between α-keto aicd group and non-α-keto aicd group[(3.37±0.82)ng/L vs (9.62±2.48)ng/L,P<0.051.There was no difference of CRP concentration between two MHD groups.As compared to non-α-keto acid group,higher SGA score(26.00±1.75 vs 22.67±2.61,P=0.001),lower MIS score(5.82±2.27 vs 10.00±2.62,P=0.002),lower left side PWV[(21.11±8.21)m/s vs(24.57±5.45)m/s,P=0.244]and lower right side PWV[(19.27±3.22)m/s vs (24.19±5.41)m/s,P=0.015]were observed in α-keto aicd group.Pearson analysis showed positive correlation between serum L-kynurenine and IL-6(r=0.352,P=0.011)and negative correlation between L-kynurenine and pre-dialysis Scr(r=-0.412,P=0.019). Conclusions Inflammation is common in MHD patients.Tryptophan degeneration product L-kynurenine may indicate inflammation status.α-keto acid improves nutritional status,anemia and arterial stiffness maybe through the alleviation of inflammation in MHD patients.