Can a blood test detect Alzhiemers Dementia before clinical symptoms appear?. If possible this is likely to transform the search for disease modifying and preventive treatments. Mark Mapstone and team of researchers from USA studied various lipids and amino acids in blood to predict who will develop cognitive decline later on.
525 community participants, aged 70 and older and otherwise healthy participated in this 5-year observational study. In the third year of the study, they selected 53 participants with either aMCI ( mild cognitive impairment ) or AD for biomarker analysis. of the 53 participants, 18 were Converters ( who converted from normal to cognitive impairment/AD status).They also selected 53 matched cognitively normal control (NC) participants. The blood tests were to quantify lipids, amino acids and biogenic amines and to see whether this would discriminate the groups with emphasis on differences that might predict phenoconversion from NC to aMCI/AD.
Analysis revealed significantly lower plasma levels of serotonin, phenylalanine, proline, lysine, phosphatidylcholine (PC), taurine and acylcarnitine (AC) in participants who later phenoconverted to aMCI/AD. Ten lipids from peripheral blood predicted the phenoconversion to either mild cognitive impairment or Alzheimer’s disease within a 2–3 year timeframe with over 90% accuracy.
This is the first published report of a blood-based biomarker panel with very high accuracy for detecting preclinical AD. The results need to be replicated in more diverse clinical cohorts.
Summary of the article: Plasma phospholipids can identify antecedent memory impairment in older adults with high degree of accuracy.Mark Mapstone et al . Nature Medicine. Published online 9 March 2014; doi:10.1038/nm.3466