Correlation Between Peripheral Blood IL-34 And Aβ42 And P-tau181 Levels In Patients With Alzheimer’s Disease

Objective: To investigate the levels of interleukin-34(IL-34),Amyloid-β42(Aβ42),and Phosphorylated microtubule-related protein tau181(P-tau181)in patients with Alzheimer’s disease(AD)with different degrees of dementia and normal control(NC)group,and to explore the correlation of IL-34 level with Aβ42 and P-tau181 in peripheral blood.Methods: This study was a case-control study.Patients who met the 2011 NIA-AA Alzheimer’s disease diagnostic criteria in the Neurological Department of our hospital from December 2021 to January 2023 were selected as mild AD(n = 24),moderate AD(n = 24),and severe AD(n = 24).Thirty-three elderly people with normal cognitive ability in our hospital were selected as normal control group(NC).All enrolled patients underwent neuropsychological assessment.Hamilton Anxiety Scale and Hamilton Depression Scale were used to exclude patients with anxiety and depression.MMSE,and Mo CA were used to evaluate cognitive function.Clinical Dementia Rating(CDR)was used to determine the severity of dementia.Medial Temporal lobe Atrophy(MTA)was assessed by 3.0T magnetic resonance imaging.Fasting venous blood samples were collected,and plasma levels of Aβ42,P-Tau181 and IL-34 were detected by Enzyme-linked Immunosorbent Assay(ELISA).The data were statistically analyzed by SPSS26.0 software and Spearman correlation analysis was used to analyze the correlation of plasma IL-34 with Aβ42 and P-Tau181 levels.Results:1.The plasma levels of Aβ42 in mild and moderate AD patients gradually increased,while decreased in severe AD patients,which were higher than that in normal control group.There were intergroup differences of Aβ42 levels among the other groups except the mild and severe AD intergroup(p < 0.05).2.The plasma levels of P-tau181 gradually increased with the decline of cognitive ability in the mild,moderate and severe AD groups,and there were significant differences in the levels of p-tau181 among the three groups(p < 0.05).3.The plasma levels of IL-34 in patients with mild,moderate and severe AD gradually decreased with the decline of cognitive ability.There were statistically differences of IL-34 levels among other groups except the moderate and severe AD intergroup.(p <0.05).4.The levels of IL-34,Aβ42 and P-Tau181 were correlated with statistical significance among the four groups(p < 0.05).The levels of Aβ42 and P-Tau181 were positively correlated,while the level of IL-34 was negatively correlated with that of Aβ42 and P-Tau181.5.The area under the curve(AUC)of P-tau181 was greater than that of Aβ42,and AUC of Aβ42 and P-tau181 combined was greater than that of single indicator.The levels of Aβ42 and P-tau181 combined had the greatest value in predicting Alzheimer’s disease.Conclusion1.The plasma level of Aβ42 increased in the early and middle stages of the AD and decreased in the late stage.With the aggravation of cognitive impairment,the level of P-tau181 gradually increased,while the level of IL-34 gradually decreased.2.The plasma levels of Aβ42,P-Tau181 and IL-34 were associated with cognitive decline in patients with AD.3.The plasma level of IL-34 in AD patients were correlated with the that of Aβ42 and P-tau181.