Diabetes, Vol 46, Issue 12 2069-2074, Copyright © 1997 by American Diabetes Association
Altered platelet membrane dynamic properties in type 1 diabetes
L Mazzanti, RA Rabini, P Fumelli, D Martarelli, R Staffolani, E Salvolini and G Curatola
Institute of Biochemistry, University of Ancona, INRCA, Italy. mazzanti@popcsi.unian.it
A modified platelet response to aggregating stimuli is supposed to play a
role in the pathogenesis of diabetic macroangiopathy. We studied the
fluidity and microheterogeneity of the external surface of the platelet
membrane and the activities of the plasma membrane Na+-K+-ATPase and
Ca2+-ATPase in 21 men with type 1 diabetes and in 20 control subjects
before and after in vitro thrombin addition. In the resting state,
platelets from type 1 diabetic patients showed an increased fluidity and
microheterogeneity of the platelet membrane, a higher Ca2+-ATPase activity,
and a reduced Na+-K+-ATPase activity in comparison with platelets from
healthy subjects. The fatty acid composition was also modified, with
increased C 16:1 and decreased C 18:0 content. Control cells incubated with
thrombin showed a modification of the membrane parameters opposite to the
response observed in type 1 cells after the stimulation. The incubation of
control platelets in the resting state with high concentrations of glucose
modified the fluidity of the plasma membrane Na+-K+-ATPase and Ca2+-ATPase
activities in an opposite way in comparison with the alterations observed
in type 1 platelets. This study suggests that in type 1 diabetic patients,
the platelet membrane responds to activation with a molecular remodeling
different from the response of healthy subjects. The abnormal organization
of the membrane might contribute to the altered platelet functions in type
1 diabetic patients, but acute exposure to high glucose levels does not
seem able to modify the platelet membrane in the way observed in type 1
diabetes.