Evaluation of miR-107, miR-128 and miR-138 level in plasma of patients with Alzheimer’s disease compared to healthy controls

Abstract

Alzheimer's disease as the most common type of dementia among elderly people, is a progressive neurodegenartive disease with a strong genetic basis in developement and progression, besides complexity in both diagnosis and treatment. Main pathogenesis of the disease emphasizes on amyloid plaques and neurofibrillary tangles. According to special pathogenesis of AD, a definite and effective treatment has not been provided so far. Current treatments are symptom based and since the AD is diagnosed at end-stages, treatments do not pause the progress of the disease, but slow the rate of progresion. On the other hand, since the process of mild neurodegeneration and memory loss starts years before clinical manifestation and major cognitive disorder, making a precise diagnosis of probable patients at early stages and gaining ability to screen at risk individuals, necesitates discovery of the methods which diagnose the disorder at the early stages. The lack of definitive diagnostic biomarkers for the Alzheimer's disease is one of major challenges. In recent years, efforts to find biomarkers that can detect the disease in the early stages have led researchers to pay attention to a group of biological molecules called micro_RNAs, which may act as promising diagnostic biomarkers, recent studies have led to the introduction of three miRNAs, miR-138, miR-128, and miR-107, as blood biomarkers in the diagnosis of the AD. Therefore, in the present project, our aim is to investigate the plasma level of expression of these genes in patients with Alzheimer's disease and its comparison to normal individuals. Materials and methods: During the diagnostic process of Alzheimer's patients, a collection of 50 blood samples from affected patients and 50 healthy individuals was obtained. Next total RNA of each sample was extracted and the expression level of target genes was measured by Real time PCR method and evaluated by suitable Statistical tests. P value <0.05 was considered as significant. Results: The level of relative expression of all three genes, studied in the patient samples was decreased compared to the healthy samples, which was statistically significant in two cases. (Pvalue = 0.047: miR-138) and (Pvalue = 0.004: miR-107), while the third gene changes between the two groups was statistically insignificant (miR = 0.75). -128 = Pvalue). However, ROC CURVE analysis was significant for all three genes