APOE GENOTYPE DOES NOT AFFECT PLASMA TPA AND PAI-1 ANTIGEN LEVELS

The presence of one or two apoliprotein E4 (apoE4) alleles constitutes a major risk factor for Alzheimer's disease (AD) and coronary heart d isease (CHD), Numerous observations have suggested that misregulation of proteases may be instrumental in both diseases, Tissue-type plasmin ogen activator (tPA) has been recently demonstrated to play a key role in neuronal plasticity and in experimental neurodegeneration, One rec eptor for the ApoE protein is the LRP/alpha 2 macroglobulin receptor, which also binds to and endocytoses tPA and plasminogen activator inhi bitor I (PAI-1). Here we tested whether the apoE genotype has an influ ence on the plasma levels of these proteins, We demonstrate that there is no difference in plasma levels of tPA- and PAI-1-antigens between middled-aged individuals with one apoE4 allele and those having none, This suggests that the impact of apoE4 on Alzheimer's disease is not t he result of altered clearance of tPA or PAI-1 by the LRP receptor. (C ) 1997 Wiley-Liss, Inc.