Background: Identification of validated peripheral biomarkers for Alzheimer's Disease, leading to an early diagnosis of the disease, would be valuable for predicting progression and targeted therapeutics. In this regard, serum levels of GADA, ZnT8A, Zn, vitamin D, and leukocyte expression of brain-derived neurotrophic factor (BDNF) gene were investigated in Alzheimer's patients and control group.
Methods: Serum levels of GADA, ZnT8A, Zn, and vitamin D and leukocyte expression of the BDNF gene were evaluated in 40 AD patients and 40 control cases. The diagnostic value of investigated factors was examined with the receiver operating characteristic (ROC).
Results: The results showed significant differences of p < 0.0001, p < 0.0001, and p = 0.0006 between AD patients and control individuals in GADA, Zn, and ZnT8A serum levels, respectively. No significant difference was observed in the serum concentration of vitamin D between AD patients and control cases (p = 0.2993). The expression level of the BDNF gene in AD patients was different from control cases, but it was not statistically significant (p > 0.05). Moreover, ROC curve analysis disclosed a diagnostic potency for serum levels of GADA, Zn, and ZnT8A for AD with an area under the ROC curve of > 0.7 (p < 0.0001, p < 0.0001, and p = 0.0007, respectively).
Conclusions: The results demonstrated the higher serum levels of GADA and ZnT8A and lower serum concentrations of Zn in the patient group. Therefore, these parameters can be discussed as possibly diagnostic in AD cases.