Alzheimer's disease (AD) pathology occurs over many years, typically decades before clinical symptoms present. The amyloid cascade hypothesis posits that beta-amyloid (Aβ) plaque burden occurs first, followed by tau neurofibrillary tangles, and ultimately neurodegeneration which manifests as cognitive impairment.

PET MRI is the gold standard for detection of Aβ and tau pathology. Amyloid PET can accurately detect Aβ burden very early on, and is also used to monitor disease progression in clinical trials. However, the expense, time commitment, and invasive nature of this procedure can be prohibitive. Blood-based (or plasma) biomarkers - amyloid peptide ratio Aβ42/40 and phosphorylated tau (p-tau) species - have recently proven to be valuable prognostic indicators of early AD pathology. A simple blood draw is less expensive, faster, and accurate, making clinical patients more open to participation in trials and long-term monitoring.

Dr. Marta Mila Aloma is a post-doctoral fellow in Dr. Tosun's lab, who has found that different levels of biomarkers in men vs women may affect how they are used for interpretation. At AD/PD in Lisbon, Portugal, she gave a talk presenting results from an analysis of plasma biomarkers in men and women from two independent cohorts. They examined 354 cognitively unimpaired (CU) participants from the ADNI, 450 CU from ALFA+ cohort, and 494 ADNI individuals with mild cognitive impairment (MCI) with available plasma biomarker measures. They studied sex differences in the association of baseline plasma biomarkers with longitudinal cognitive change (up to 5years) in three different cognitive measures: mPACC (CUs) or in ADAS13...