MEMBRANE MODIFICATIONS OF RED-BLOOD-CELLS IN ALZHEIMERS-DISEASE

Red blood cells (RBC) from 24 Alzheimer's disease (AD) patients, 18 ag e- and sex-matched nondemented (ND) patients, hospitalized in the same facility for orthopedic problems, and 18 healthy volunteers aged 30-5 2 years were studied in order to gain insight into the nature of RBC m embrane modifications in AD. Significant differences were found betwee n RBC from AD and ND patients or young controls respectively for annex in V-binding (45.5 +/- 18.0% vs 27.1 +/- 14.7 and 2.7 +/- 1.9, p = .00 3), fraction of glycerol resistant cells (30.8 +/- 11.1% vs 19.6 +/- 6 .4 and 10.2 +/- 3.1, p = .026), cell electrophoretic mobility in polym er (1.028 +/- 0.022 mu m sec(-1) V-1 cm vs 1.046 +/- 0.022 and 1.053 /- 0.021, p = .02) and only limited significance for the filterability (1.46 +/- 0.12 msec vs 1.58 +/- 0.11 and 1.54 +/- 0.11, p = 0.1). A l ogistic analysis, using simultaneously several features as independent variables, suggested the combined use of annexinV-binding, glycerol r esistance, and cell filterability which allowed the assignment of 95% of patients from this cohort to the right group. A prospective analysi s of a larger cohort is required for the estimation of the diagnostic value of this test battery. In addition, the high level of annexin bin ding is characteristic of a disruption of the phospholipid asymmetry i n aged or damaged cells, while the high glycerol resistance combined w ith low electrophoretic mobility and rigidity characterize young RBC, thus indicating an enhanced turnover of RBC in Alzheimer's disease.