Exercise-induced platelet and leucocyte activation is not enhanced in well-controlled Type 1 diabetes, despite increased activity at rest.

AIMS/HYPOTHESIS: Stress can evoke a prothrombotic state with activated platelets and leucocytes, and increased platelet activation at rest has been reported for diabetic subjects. Thus, prothrombotic responses to stress may be enhanced in diabetes mellitus. We therefore evaluated platelet and leucocyte responses to exercise in Type 1 diabetic patients.

METHODS

Type 1 diabetes mellitus patients with good metabolic control and healthy subjects matched for age and body mass index ( n=15 for both) performed a maximal exercise test. Platelet and leucocyte activation and their heterotypic aggregation were monitored by whole blood flow cytometry.

RESULTS

Diabetic platelets did not show higher basal levels of P-selectin expression, but were more reactive to ADP and thrombin stimulation. Diabetic patients had increased lymphocyte and monocyte CD11b expression, and increased circulating platelet-monocyte aggregates. Exercise evoked thrombocytosis, increased circulating platelet P-selectin expression, enhanced platelet sensitivity to ADP and thrombin, and elevated plasma levels of soluble P-selectin to a similar degree in diabetic patients and healthy subjects. Exercise induced marked leucocytosis and elevated plasma elastase, but only slightly increased leucocyte CD11b expression and leucocyte reactivity to stimulation by N-formyl-methionyl-leucyl-phenylalanine. In all of these there was no difference between diabetic patients and healthy subjects. The numbers, but not percentages of circulating platelet-leucocyte aggregates were markedly increased by exercise, but the increase was less prominent among diabetic patients.

CONCLUSIONS/INTERPRETATION: Strenuous exercise evokes platelet and leucocyte activation in Type 1 diabetic patients and healthy subjects. Platelet and monocyte hyperactivity were found at rest, but responses to stress were not augmented in metabolically well-controlled Type 1 diabetes mellitus patients.