Endurance training alters enzymatic and rheological properties of red blood cells (RBC) in type 2 diabetic men during in vivo RBC aging.

This study examines the effects of endurance training on red blood cells (RBC) in seventeen non-insulin-dependent type 2 diabetic men with a special focus on in vivo RBC aging. Venous blood was collected pre- and post-training at rest. RBC from whole blood and RBC separated according to cell age by density-gradient centrifugation were analyzed. RBC deformability was measured by ektacytometry. Immunohistochemical staining was performed to quantify the RBC-nitric oxide (NO) synthase activation (RBC-NOSSer1177) because RBC-NOS-produced NO can contribute to increased RBC deformability. The proportion of "young" RBC was significantly higher post-training. RBC deformability of all RBC (RBC of all ages) remained unaltered post-training. During RBC aging, RBC deformability decreased in both pre- and post-training. However, the training significantly increased RBC deformability in "young" and reduced their deformability in aging RBC. RBC-NOS activation remained unaltered in all RBC post-training. It tendentially increased in aging RBC pre-training, but did not change during aging post-training. The training significantly reduced RBC-NOS activation in "old" RBC. Endurance training may improve the RBC system (higher amount of "young" RBC which are more deformable). It remains speculative whether changes in older RBC (reduced RBC-NOS activation and deformability) could lead to more rapid elimination of aged RBC.