MODERATE EXERCISE LEADS TO DECREASED EXPRESSION OF BETA-1 AND BETA-2 INTEGRINS ON LEUKOCYTES

Intravascular adhesion of leucocytes plays a role in the pathogenesis of acute and chronic vascular disease. Regular aerobic exercise seems to protect against vascular disease. Since leucocyte adhesion is media ted by integrins, we tested the hypothesis that surface expression of the integrin adhesive receptors LFA-1 (cd11a/cd18), MAC-1 (cd11b/cd18) . gp 150/95 (cd11c.cd18), and VLA-4 (cd29/cd49) is decreased by modera te endurance exercise, Surface expression of integrins was measured by FAGS analysis in 19 healthy subjects (16 males, 3 females, 36.6 +/- 8 .7 years, 177.1 +/- 7.5 cm, 70.3 +/- 8.1 kg) before and after sub-maxi mal exercise (3 h run) using monoclonal antibodies against cd11a, cd11 b, cd11c, cd18, cd29 and cd49. In addition, wee compared resting integ rin expression in this group with a group of sedentary subjects (19 ma les, 6 females, 29.3 +/- 5.3 years), White blood cell count increased from 5300 ml(-1) to 9740 ml(-1) during exercise (P<0.001), Nevertheles s, the expression (indicated by the mean log fluorescence) of cd11a (9 4 +/- 24 vs. 78 +/- 14) and cd18 (128 +/- 31 vs, 102 +/- 21) on lympho cytes and of cd11a (104 +/- 25 vs, 85 +/- 16), cd11c (497 +/- 171 vs, 408 +/- 126) cd29 (109 +/- 16 vs, 89 +/- 16), cd49 (69 +/- 8 vs, 54 +/ - 11) on monocytes was decreased after exercise (all P<0.05). In contr ast, integrin expression on granulocytes was not altered by exercise, Comparison of exercising and sedentary subjects showed a significantly decreased expression bf integrins in exercising subjects, Our results demonstrate that moderate exercise leads to decreased expression of i ntegrin receptors on leucocytes. This decreased expression of adhesion molecules may result in decreased adhesion and infiltration of leucoc ytes into the vessel wall. This phenomenon may play a role in the bene ficial effect of moderate exercise in prevention of acute and chronic vascular disease.