维持性血液透析患者犬尿氨酸与营养状态及血管硬化的关系

目的 研究长期维持性血液透析（MHD）患者血清犬尿氨酸的变化及其与患者营养状态和血管硬化的关系。 方法 纳入年龄性别相匹配的健康对照、长期服用α酮酸的MHD患者、未服用α酮酸的MHD患者各20例。用高效液相色谱法测定3组的血清犬尿氨酸水平。测定两组MHD患者C反应蛋白（CRP）水平。用主观综合性营养评估（SGA）及炎性营养不良评分（MIS）对两组MHD患者进行营养评估。用脉搏波传导速度（PWV）评估动脉硬化情况。 结果 MHD患者血清犬尿氨酸水平显著高于健康人（3.20±1.12） μmol/L 比（1.74±0.27） μmol/L，P < 0.01]。服用α酮酸组与未服用α酮酸组血清犬尿氨酸水平差异无统计学意义（3.20±0.88） μmol/L比（3.29±1.34） μmol/L，P > 0.05]。MHD患者血白细胞介素6（IL-6）水平显著高于健康对照组（6.45±3.78） ng/L比（1.38±1.59） ng/L，P < 0.01]。α酮酸组IL-6水平显著低于非α酮酸组（3.37±0.82） ng/L比（9.62±2.48） ng/L，P < 0.05]；2组间CRP水平差异无统计学意义。与非α酮酸组比较，α酮酸组SGA评分较高（26.00±1.75比22.67±2.61，P = 0.001），MIS评分较低（5.82±2.27比10.00±2.62，P ＝ 0.002），左、右侧PWV均较低（21.11±8.21） m/s比（24.57±5.45） m/s，P = 0.244；（19.27±3.22） m/s比（24.19±5.41） m/s， P = 0.015]。 相关分析显示，血清犬尿氨酸与血IL-6呈正相关（r ＝ 0.352，P ＝ 0.011）；与透析前Scr呈负相关（r = -0.412，P = 0.019）。 结论 MHD患者普遍存在炎性反应状态，色氨酸代谢产物犬尿氨酸水平可反映这种炎性反应状态。α酮酸可能通过减轻其炎性反应程度从而改善MHD患者的营养、贫血及血管硬化。

Association of serum L-kynurenine with nutritional status and vascular stiffness in maintenance hemodialysis patients

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,P<0.01],while such difference was not found between α-keto aicd group and non-α-keto-aicd group (3.20±0.88)μmol/L vs (3.29±1.34)μmol/L,P>0.05].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.