| OBJECTIVE:Diabetes mellitus combined with cognitive impairment has become one of the common central nervous system complications of diabetes mellitus and is an important cause of reduced standard of living and reduced life expectancy in diabetic patients.Since there is a lack of specific biomarkers for diabetes-related cognitive decline,this study investigated the risk factors of patients with mild cognitive impairment in type 2 diabetes and further investigated the aberrant metabolic pathways and specific biomarkers for mild cognitive impairment in type 2 diabetes based on a combined transcriptomic and non-targeted metabolomic analysis.METHODS:This study was divided into four main parts:1.First,statistical analysis was performed for clinical patient information,and 104 patients with type 2 diabetes who were hospitalized at the Department of Endocrinology of the Second Hospital of Shandong University between July 2021 and September 2022 were selected.The Montreal Cognitive Assessment Test(MoCA)was applied to assess cognitive function.The population was divided according to MoCA scores,with 58 cases of diabetes combined with the mild cognitive impairment group(T2DM-MCI)(MoCA<26)and 46 cases in the diabetes alone group(T2DMNCI)(MoCA≥26).Demographic information,disease characteristics,and clinical laboratory indices of the patients were collected for risk factor analysis in this population.2.Transcriptomic datasets from 2 db/db mouse models related to cognitive impairment in diabetes were screened through the GEO database,and individual datasets were analyzed based on the Gene Ontology database(GO)and the Kyoto Encyclopedia of Genes and Genomes(KEGG),respectively Differential gene analysis and pathway enrichment were performed.3.Ten serum specimens from each group of 20 patients were selected from the collected clinical patients,and LC-MS/MS untargeted metabolomics techniques were applied to detect metabolite data between the two groups,and differential metabolite analysis and pathway enrichment were performed.4.The results of the transcriptomic analysis were combined with metabolomic differential metabolite pathways Combine the results of the transcriptomic analysis with metabolomic differential metabolite pathways to identify co-variant KEGG metabolic pathways and search for possible biomarkers and pathogenic mechanisms.Results:1.General information and independent risk factors of the enrolled population:Subjects were divided into T2DM-MCI and T2DM-NCI groups according to MOCA scores for comparison between groups,which showed statistical differences in age(62.97 years vs.57.24 years,P=0.004),years of education(9 years vs.12 years,P=0.000),total cholesterol(4.64mmol/L vs.4.33mmol/L,P=0.049),and fasting blood glucose(8.37mmol/L vs 8.19mmol/L,P=0.048)were statistically different.Correlation and multiple regression analyses for the above variables revealed that years of education would have a significant positive relationship with MoCA scores.Age had a significant negative effect on MoCA scores.Further applying binary logistic regression analysis,the results suggested that advanced age(OR=1.083,95%CI:1.023-1.146,p=0.006),and short years of education(OR=0.631,95%CI:0.502-0.795,p=0.000)were independent risk factors for mild cognitive impairment in patients with type 2 diabetes.2.Analysis of the mouse hippocampal transcriptome dataset:The results suggest that the immune system and inflammation-related pathways may play a key role in the progression of T2DM-MCI.Multiple metabolic pathway abnormalities were also identified,such as inhibition of bile secretion,fatty acid degradation,fatty acid metabolism,glycolysis/glycogenesis-related pathways,and activation of degradation pathways for valine,leucine,and isoleucine.3.Non-targeted metabolomics data showed that there were 10 differential metabolites in T2DM-MCI compared to T2DM-NCI,including bile acids,thymidine,amino acids,and cucurbitacin,with the most significant alterations in bile acid metabolism-related products,as evidenced by three bile acid metabolites,Glycolithocholic acid(GLCA),Glycochenodeoxycholic acid(GCDCA),Chenodeoxycholic acid(CDCA)products were upregulated.Two metabolic pathways,primary bile acid biosynthesis,and pyrimidine metabolism were also enriched.4.Integration of transcriptomics with metabolomics revealed a significant downregulation of the bile secretion pathway-related genes Slcolb2 and Aqp1 and a significant alteration in the bile secretion pathway,as well as a significant increase in bile acid-related products(GLCA,GCDCA,CDCA).Conclusions:1.Patients with T2DM who are elderly,have low levels of education,hyperglycemia,and hypercholesterolemia may be more likely to develop mild cognitive impairment.Short years of education and advanced age may be independent risk factors for T2DM-MCI.2.Analysis of the mouse hippocampal transcriptome dataset revealed that multiple metabolic pathways such as the immune system,inflammation,and biliary secretion may play a crucial role in the progression of T2DM-MCI.3.Non-targeted metabolomics results revealed differences in serum metabolite profiles between T2DM-MCI patients and cognitively normal T2DM patients.The most pronounced alterations were found in bile acid metabolism-related products,of which the upregulated GLCA,GCDCA,and CDCA may be specific biomarkers for T2DM-MCI,and there was a significant disturbance of bile acid metabolism in T2DM-MCI.4.Combined analysis of transcriptomic results with metabolomic findings suggested that dysfunction of OATPs and AQP and disturbance of bile acid metabolism play an important role in T2DM-MCI. |
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