FREE-RADICALS AND SUPEROXIDE-DISMUTASE IN BLOOD OF PATIENTS WITH ALZHEIMERS-DISEASE AND VASCULAR DEMENTIA

We measured hydroxyl radical ((OH)-O-.) levels in blood, superoxide di smutase (SOD) activity in red blood cells (RBC) relative to both total protein (RBC-SOD/P) and Cu,Zn-SOD protein (RBC-SOD/SOD), SOD activity in plasma (plasma-SOD), and Cu,Zn-SOD protein relative to total RBC p rotein (Cu,Zn-SOD/P) in 22 patients with probable dementia of the Alzh eimer type (DAT group, mean age 74.8+/-9.4 years), 16 with probable va scular dementia (VAD group, mean age 76.9+/-6.7 years) and 19 non-deme nted controls (control group, mean age 73.5+/-6.2 years). Levels of (O H)-O-. in the DAT and VAD groups were significantly (P<0.01 and P<0.00 1, respectively) higher, whereas the values of RBC-SOD/P and RBC-SOD/S OD in these two groups (both P<0.001) and Cu,Zn-SOD/P in the DAT group (P<0.001) were significantly lower than the corresponding control val ues. Members of the VAD group with risk factors for stroke (RF+ group) showed significantly higher (OH)-O-. levels than members of the VAD g roup without risk factors (RF- group; P<0.01) and the control group (P <0.001). RBC-SOD/P and RBC-SOD/SOD values in the RF+ group were signif icantly (both P<0.01) lower than the corresponding control values, The re were no significant differences among the VAD, RF+ and control grou ps with respect to Cu,Zn-SOD/P values, of between the RF- and control groups for any measured parameter. We conclude that oxidative stress p lays a role in the brain damage seen in both DAT and VAD, and that the causes of decreased SOD activity in RBC differ between DAT and VAD pa tients. (C) 1997 Elsevier Science B.V.