SERPINE1 and Cognitive impairment: This findingsuggests that measurement of this ratio may provide an indicationof the degree of cognitive impairment in Alzheimer possibly causedby a concomitant PAI-1 increase and reduced conversion of proBDNFto mature BDNF.3,36-39 Supporting this hypothesis, BDNFserum levels were significantly lower in Alzheimer patients with dementiaas compared to amnestic mild cognitive impairment patients (13.7%less), a finding consistent with previous studies reporting reducedlevels of BDNF in Alzheimer patients.21,40-42