Cell-Free mtDNA Quantification in Alzheimer's Patients from the Mexican American Population

Abstract Background AD is a continuous problem in the 65+ population but it is especially challenging in the Hispanic population where not only is it more prevalent but more severe than Caucasian populations. This study explores the efficacy of using peripheral blood plasma as an alternative tissue for testing as well as the usefulness for future research assisting in identifying the population structure most at risk for developing AD based upon CF-mtDNA quantity results. Materials and Methods Samples tested included a total cohort (Mexican American and Caucasian) of 177 individuals (AD=45, MCI=74, NC=58). The Mexican American subset contained 92 individuals (AD=21, MCI=53, and NC=18). Peripheral blood plasma was collected from the TARCC biobank and quantified. CF-mtDNA was then tested for significance using correlation analyses, logistic and linear regression models. Results CF-mtDNA was significantly negatively correlated with education, age, sex, and hypertensive samples in the total and Mexican American populations. The greatest difference was expected to be in CF-mtDNA quantity from NC to AD samples. Instead, the most significant difference was between MCI and NC samples. As CF-mtDNA quantity increased, the MMSE and CDRSOB scores were less impaired. Conclusion In conclusion, CF-mtDNA is an easily accessible and easily tested molecular marker of diseases that are relevant to studies for cognitive decline. Although our findings were inconsistent with current literature, they bring to light the weight of confounding factors within limited sample studies. With the completion of the full sample set associated with this study, more power is needed to overcome these issues.