Aβ1-40 and Aβ1-42 Plasmatic Levels In Stroke: Influence of Pre-Existing Cognitive Status and Stroke Characteristics

Many stroke patients have pre-existing cognitive impairment. Plasma amyloid beta peptides (A beta)-possible biomarkers of Alzheimer's pathology-induce vascular dysfunction. Our objective was to evaluate factors influencing plasma A beta 1-40 and A beta 1-42 peptides in a cohort of stroke patients. In the Biostroke study (ClinicalTrials. gov Identifier: NCT00763217), we collected vascular risk factors, neuro-imaging features and biological tests including A beta 1-40 and A beta 1-42. We used the Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE) to systematically assess the pre-existing cognitive status. Of 403 patients (371 ischemia), 25 met criteria for pre-existing dementia, 142 for pre-existing cognitive decline-no-dementia, and 236 had no PCoI. A beta 1-42 was independently associated with PCoI (odds ratio 0.973; 95% confidence interval: 0.950-0.996; p=0.024). Factors associated with plasma A beta 140 were age, smoking and diabetes mellitus. After exclusion of hemorrhagic strokes, the results remained unchanged, but blood samples taken less than 12 hours after onset were associated with lower plasma A beta 1-40. Our results support a dissociated response of the 2 plasma A beta peptides in stroke patients, plasma A beta 1-40 being involved in vascular aspects whereas A beta 1-42 might be involved in neurodegenerative processes.