Summary
Measurements of platelet aggregation and adhesion have proved disappointing in the
study of individual subjects with, or at risk from, arterial disease. In this paper
the technique of platelet electrophoresis is described, and it is shown that with
this technique individual patients with coronary artery disease can be identified
with a high degree of accuracy. Abnormal platelet electrophoretic behaviour is also
described in the relatives of subjects who have had a myocardial infarction at an
early age, and it is suggested that the platelet abnormality precedes clinically-detectable
disease.
The platelet abnormality is shown to be secondary to changes in the plasma, and experiments
are described in which a start has been made in elucidating the nature of the plasma
abnormality. Two plasma components are involved: one is probably adenosine diphosphate
(ADP), and it is shown that ADP has two distinct effects on platelets; the other component
is associated with the plasma low-density lipoproteins.
The nature of the low-density lipoprotein abnormality that induces platelet changes
that can be detected by this electrophoretic technique appear of extreme importance
in the understanding of thrombosis. No specific chemical abnormality has been identified
in these lipoproteins, but certain detergents are shown to have a similar effect on
platelet electrophoretic behaviour. It is therefore suggested that there are changes
in the surface-active, or detergent, properties of the lipoproteins in subjects with,
or at risk from, arterial disease.
