Differential Serum Amino Acid Profiles In Chronic Kidney Disease Patients Of Differing Pathoetiologies

ObjectiveThis study used Reverse-phase High-performance liquid chromatography(RP-HPLC)to compare the serum amino acid(AA)profiles in CKD patients of different pathogenesis,and then analyzed the correlation between amino acid levels and multiple clinical indicators such as eGFR,plasma albumin.To discuss the relationship between the difference amino acid metabolism in CKD patients of different pathogenesis and the occurrence and development of diseases.MethodsA total of 79 adults with advanced CKD with an estimated glomerular filtration rate(eGFR)under 20 ml/min/1.732 were segregated into three cohorts by pathoetiology: Diabetic Nephropathy(DN,n=20),Hypertensive Nephropathy(HN,n=26),and Chronic Glomerulonephritis(CGN,n=33).Otherwise Twenty-five gender-matched healthy adults were selected as healthy controls(HC,n=25).Early-morning fasting serum samples were collected,processed,and the serum concentrations of 24 AA among 4cohort were determined by RP-HPLC.And One-way analysis of variance(ANOVA)or Kruskal-Wallis rank test followed by post-hoc testing wasused to compare data among multiple groups after checking for normality by Shapriro-Wilk.Results1.All three CKD cohorts were characterized by the following serum amino acid profile relative to HC cohort: serum lysine,serine,glycine,GABA,tryptophan,leucine and tyrosine levels were significantly decreased(p<0.05),and serum ammonia levels were significantly increased(p<0.05).2.The DN cohort alone was characterized by the following serum amino acid profile relative to other three cohorts: serum threonine levels was significantly increased and serum Aspartic acid levels was significantly decreased(p<0.05),and compared with HC cohort : serum proline levels was significantly increased and serum ornithine levels was significantly decreased(p<0.05).3.The HN cohort alone was characterized by the following serum amino acid profile relative to CGN cohort : serum threonine,isoleucine and ornithine levels were significantly increased(p<0.05).4.The CGN cohort alone was characterized by the following serum amino acid profile relative to DN and HN cohorts: serum isoleucine levels was significantly decreased(p<0.05),and compared with HC cohort :serum proline levels was significantly increased,serum ornithine and Phenylalaine levels was significantly decreased(p<0.05).5.By Spearman correlation analyses,eGFR in CKD patients was positively correlated with serum lysine,serine,glycine,GABA,tryptophan,leucine and tyrosine levels(p<0.05),and negatively correlated with serum proline level(p<0.05).Plasma albumin in CKD patients was positively correlated with serine,glycine,GABA,tryptophan and tyrosine levels(p<0.05),and negatively correlated with serum ammonia level(p<0.05).Notability,serum tryptophan levels were Strong positively correlated with eGFR and serum albumin levels in CKD patients(r > 0.50,p<0.001).6.Spearman correlation analyses by cohort revealed that : In DN cohort,the serum tyrosine and ammonia level was positively correlated with eGFR(p<0.05),serum serine and lysine levels were positively correlated with blood glucose(p<0.05),serum tryptophan levels were positively correlated with total cholesterol(p<0.05);In HN cohort,serum proline level were negative correlated with eGFR(p<0.05),serum Glycine level were negative correlated with triglyceride(p<0.05);In CGN cohort,total cholesterol was negative correlated with serum serine(p<0.05),and positively correlated with serum aspartic acid and ammonia levels(p<0.05).ConclusionCKD patients display significant dysregulation in their serum amino acid profiles.There were significant diffences in some serum amino acid levels in CKD patients of different pathogenesis,The difference oftryptophan levels in CKD patients of different pathogenesis may be one of the reasons for the disagreement of the rate of renal function deterioration.