The Correlation Study Between Abnormal Metabolites Of Amino Acids And Lipids In Type 2 Diabetic Nephropathy

Background:Diabetic nephropathy(DN)is one of the major complications of diabetes mellitus,and its mortality is second only to cardiovascular and cerebrovascular diseases in type 2 diabetes mellitus.However,the early diagnosis of DN by existing indicators not clearly.Therefore,the discovery of early biomarkers of DN is more insignificant for effective prevention and treatment of DN.We want to analyze the metabolites of amino acids,acyl carnitine and lipids using metabonomics to explore biomarkers that can predict the early stage of DN and associated with DN disease progression.Methods:This study was a cross-sectional study,total of 836 hospitalized patients’ general clinical data and clinical observation indicators were collected.General clinical data included: name,gender,age,and clinical observation indicators included:Random urinary albumin/uric creatinine urinary inhibition(ACR),cystatin C(Cys-C),serum creatinine(Cr),hypersensitive c-reactive protein(hs-CRP),cholesterol,triglyceride,low density lipoprotein cholesterol(LDL-c),high-density lipoprotein cholesterol(HDL-c),apolipoprotein A and apolipoprotein B,and through the chromatography-mass spectrometry(MS),nuclear magnetic resonance(NMR)spectroscopy of metabonomics method to detect the serum metabolites:Amino acid,acyl carnitine and lipid were divided into amino acid,acyl carnitine metabolism group(group A)and lipid metabolism group (group B)according to clinical observation indexes.Group A had 459 patients and group B had 377 patients.Each group was divided according to the ratio of urinary albumin/creatinine(ACR).The included patients were divided into 4 groups in each group: Group 1(normal control group):healthy patients admitted to our hospital during the same period;2 group(diabetic microalbumin negative group): theoretically including diabetic nephropathy group and diabetic nephropathy stage 1 and 2 patients,according to the WHO diagnostic criteria and classification criteria of diabetes,random urine microalbumin/urinary creatinine <30ug/mg,GFR≥90ml/min.1.73m2;Group 3(early diabetic nephropathy group):persistent microalbuminuria,randomized urine microalbuminuria/urinary creatinine: 30-299ug/mg,GFR≥90ml/min.1.73m2;Group 4(diabetic nephropathy clinical stage/uremia stage group): randomized urinary albumin/urinary creatinine ≥300ug/mg,regardless of whether the GFR decreased.Chi-square test was applied to the disordered count data.One-way ANOVA was used to compare the measurement data in line with normal distribution among groups,and independent sample T test was used to compare the measurement data between two groups.The measurement data of non-normal distribution should be analyzed by non-parametric test.The changes of amino acids,lipids,acylcarnitine and other metabolites in the occurrence and development of DN and their diagnostic significance among the four groups were analyzed.Results: With the gradual decline of renal function,ACR was gradually increased,and glutamate,tryptophan,tyrosine and piperamide were gradually decreased.The values of glutamate,tryptophan,tyrosine and piperamide were the highest in A1 group,followed by A2 group,A3 group and A4 group,and the differences were statistically significant when comparing A2,A3 and A4 groups with A1 group(P<0.01).Cys-C,super sensitive C-reactive protein,triglyceride,eicosenoic acid and eicosadienoic acid were gradually increased,and Cys-C was successively increased in groups B1,B2,B3 and B4,and the difference was statistically significant between group B1 and B3,B1 and B4,and B2 and B4(P<0.01).The uric acid in B1,B2,B3 and B4 groups was increased successively,and the difference was statistically significant in B1,B2 and B3 groups compared with B4 group respectively(P<0.01).Hypersensitive C-reactive protein was increased successively in B1,B2,B3 and B4 groups,and the difference was statistically significant among all groups(P<0.01).Triglycerides in group B1,B2,B3,B4 was higher in turn,B2,B3,B4 group when compared with group B1 and B2 respectively between B4 group and there was a significant statistical significance(P< 0.01),eicosenoic acid in group B1,B2,B3,B4 was higher in turn,the difference in the group of B2,B3 and B4 group when compared with group B1 and B2,respectively,compared with B4 group have significant statistical significance(P<0.01),eicosadienoic acid in B1,B2,B3 and B4 groups was successively increased,and the difference was statistically significant when B2,B3 and B4 groups were compared with B1 group and B2 and B4 groups respectively(P<0.01).Arachidonic acid,behenic acid,xytaric acid,palmitic acid and total saturated fatty acids first decreased and then increased,arachidonic acid was the greatest in group B1 followed by group B4 followed by group B3 followed by group B2 and group B3 followed by group B2 and group B2 and group B3 followed by group B4.The difference was statistically significant when comparing group B2 and B3 with group B1 and group B2 and group B3 with group B4(P<0.01).Behenic acid was the greatest in group B1 followed by group B4 followed by group B3 followed by group B2 and the smallest in group B2 and there was a significant difference between group B2 and group B3 and group B1 and group B2 and group B3 and group B4(P<0.01).The value of lignotaric acid was the highest in group B4,followed by group B1,group B3,and group B2.The difference was statistically significant between group B1 and group B2,as well as between groups B2,B3 and B4(P<0.01).The palmitic acid value in group B4 was the highest,followed by group B1,group B3 was the second,and group B2 was the lowest.This difference was statistically significant when comparing group B2 and group B3 with group B1 and group B2 and group B3 with group B4(P<0.01).Total saturated fatty acid(TFA)was the highest in B4 group,followed by B3 group,B1 group and B2 group,and the lowest in B2 group.This difference was statistically significant when comparing B2 and B3 groups with B1 group and B2 and B3 groups with B4 group respectively(P<0.01).Conclusions:A total of 35 metabolites were associated with type 2 diabetic nephropathy.With the decrease of renal function,ACR increased gradually,and 4 metabolites decreased gradually,including glutamic acid,tryptophan,tyrosine and piperamide.Four metabolites,including Cys-C,super-sensitive C-reactive protein,triglycerides,and eicosenoic acid,were increased gradually.Changes in these metabolites may be related to disease progression and can be used as biomarkers to predict the progression of type2 diabetic nephropathy.And five of these metabolites: arachidonic acid,behenic acid,woody tar acid,palmitic acid and total saturated fat tended to go down first and then up and might be biomarkers for predicting the early stage of type 2 diabetic nephropathy.