Related Experiment Videos
Regulation of MAC-1 (CD11b/CD18) expression on circulating granulocytes in endurance runners
1Franz Volhard Clinic at the Max Delbrück Centrum for Molecular Medicine, Virchow Klinikum, Humboldt University, Berlin, Germany. jordan@fvk-berlin.de
Insights
Intense exercise, like marathon running, increases CD11b expression on granulocytes, potentially aiding tissue infiltration. Moderate exercise does not show this effect.
Area of Science:
- Exercise physiology
- Immunology
- Cellular biology
Background:
- Granulocyte integrins, such as MAC-1 (CD11b/CD18), play a role in immune cell adhesion and migration.
- Endurance exercise can modulate immune cell function and expression of cell surface receptors.
Purpose of the Study:
- To investigate the relationship between exercise duration/intensity and granulocyte degranulation and MAC-1 (CD11b/CD18) upregulation.
- To determine if body temperature or dehydration influences MAC-1 expression.
- To test if changes in leukocyte counts and MAC-1 expression during endurance exercise are independently regulated.
Main Methods:
- Eight amateur runners underwent maximal treadmill tests, a 3-h moderate run, and a marathon race.
- Granulocyte MAC-1 (CD11b/CD18) surface expression was measured using fluorescent antibody cell sorting before and after each exercise protocol.
Main Results:
- CD11b expression on granulocytes significantly increased after maximal treadmill testing (10+/-9.6%) and marathon running (84+/-76%).
- No significant change in CD11b expression was observed after moderate 3-h running.
- CD18 expression remained unchanged across all exercise protocols.
Conclusions:
- Intense endurance exercise, including maximal testing and marathon running, upregulates CD11b expression on granulocytes.
- This upregulation of integrin adhesive receptors may contribute to granulocyte adhesion to endothelial cells and tissue infiltration post-exercise.
- Moderate endurance training does not appear to induce similar changes in CD11b expression.
Purpose:
We tested the hypothesis that degranulation of granulocytes and upregulation of the granulocyte integrin MA-1 (CD11b/CD18) are related to exercise duration and/or intensity. We also investigated whether or not the expression of MAC-1 would be influenced by body temperature or dehydration. Moreover, we tested the hypothesis that changes in leukocyte counts and changes in MAC1 expression with endurance exercise are independently regulated.
Methods:
In eight amateur runners, MAC-1 (CD11b/CD18) surface expression on granulocytes was determined by fluorescent antibody cell sorting, before and after an incremental maximal treadmill test, a moderate 3-h run, and a competitive marathon race.
Results:
Expression CD11b on granulocytes was increased by 10+/-9.6% (P < 0.05) after the maximal treadmill test and by 84+/-76% (P < 0.01) after the marathon run. There was no change in CD11b expression after the moderate 3-h run. CD18 expression was not significantly changed after any of the exercise protocols.
Conclusion:
Expression of CD11b on granulocytes is increased with intense endurance exercise, either incremental maximal treadmill testing or competitive marathon running, but not in moderate endurance training. Thus, exhaustive exercise may be one mechanism for the upregulation of integrin adhesive receptors on granulocytes. This phenomenon could be in part responsible for increased adhesion of granulocytes to endothelial cells and could facilitate tissue infiltration after endurance exercise.