Question: 

Transfusing red blood cells (RBCs) is the oldest form of blood doping and recent media reports suggest that it is still widely used among different groups of athletes. Our research group has demonstrated that the procedure of blood-sampling, storage, and re-infusion in patients with hip-surgery induce an increase in NOS activity in the RBC blood concentrate as well as in the patient's blood after re-infusion. These findings implicate that the RBC NOS system can be used for the detection of autologous blood doping in sports.

Purpose: 

We hypothesized that the determination of the relation of highly activated towards low-activated RBCs in any single blood sample might be used as indicator for autologous blood doping in sports.

Methods: 

Subjects received a medical examination prior to the study which included a routine check of blood parameters as well as iron status. Subjects donated 500 mL of blood according to standard medical blood donation procedure. After 4 weeks, the blood was re-infused. Blood samples were drawn off the subjects at different time points before, during and after the blood donation and re-infusion process (see below).

Results: 

Although common blood parameters showed the expected changes during the withdrawal and re-infusion period of the experiment, RBC NOS phosphorylation at serine 116 did not change over the time course of the study. The initial value from densitometric analysis of 14.6 ± 3.3 arGV decreased significantly over the course of the study, measuring 9.6 ± 4.4 arGV 14 days after reinfusion (p = 0.001). This change was accompanied by a significant decrease in reticulocyte number. This long-term effect was accompanied by a reduction of reticulocyte number from initially 9.1 ± 2.4 ‰ to 6.4 ± 2.0 ‰ at the end of the trial (p=0.02).

Conclusions: 

Blood donation, but not RBC re-infusion activates RBC NOS system in healthy, moderately trained subjects. Therefore, eNOS activation does not seem to be a valuable parameter for the detection of autologous blood doping in sports. However, the procedure of blood donation and re-infusion after 4-weeks is accompanied by a reduction of Ser116 phophorylation in RBCs as well as a decrease in reticulocyte number. This might possibly be explained by the reduction in reticulocyte production follwoing blood re-infusion and hence the aging of erythrocytes which might have effects on the phosphorylation status of RBC NOS.