Patterns of exercise-related inflammatory response in sickle cell trait carriers

To clarify whether sickle cell trait (SCT) carriers (SCT group) present a specific postexercise inflammatory response to repeated and strenuous exercise.

The patterns of inflammatory markers in response to repeated heavy exercise were investigated in SCT carriers (SCT group: eight men, 20.0+/-0.7 years) and subjects with normal haemoglobin (CONT group: seven men, 20.6+/-0.7 years). The exercise consisted of three successive maximal ramp exercise tests, interspaced with 10 min of recovery, and accomplished at room temperature. Blood was sampled at rest (T(R)), at the end of each of the three tests (T(1), T(2), T(3)) and during the immediate (T(1 h), T(2 h)) and late (T(24 h), T(48 h)) recovery periods. Standard haematological parameters and plasma levels of cytokines (TNFalpha, IL-6) and adhesion molecules: soluble L- and P-selectins (sL-selectin, sP-selectin), soluble vascular cell adhesion molecule-1 (sVCAM-1), soluble intracellular adhesion molecule-1 (sICAM-1) were measured.

In both groups, the three successive maximal exercise bouts prompted an inflammatory response (ie, white blood cells and IL-6 levels increased in response to exercise). sICAM-1 and sVCAM-1 levels did not change during or after exercise and presented no difference between groups. However, during exercise, sL-selectin and sP-selectin kinetics differed between groups: sL-selectin increased earlier in the SCT group than in the CONT group, and sP-selectin statistically increased only in the SCT group.

Although the data do not indicate an extended exercise inflammatory response in SCT carriers, a specific activation of the L- and P-selectins was observed. Further studies are needed to determine whether the selectins' changes are evidence of greater risk for SCT carriers during physical exercise in specific conditions or an indication of a protective mechanism mediated by the shedding process of adhesion molecules.