Detection of rhEPO microdosing and small-volume blood transfusion
In this 3-year international collaborative project, we will consolidate and expand the existing Athletes Biological Passport (ABP) approach as well as evaluate new strategies for detection of blood manipulation.
The project consists of two clinical trials where samples are collected from four week doping regimes expected to be currently used by cheating athletes: A) autologous blood transfusion of volumes <150 ml packed red blood cells;
B) frequent intravenous injections of <10 IU per kg bw of recombinant human erythropoietin. Samples collected from these main trials will be subjected to different analytical approaches, comprising ABP analyses including the abnormal blood profile score (ABPS); evaluation of reticulocyte percentage as a standalone marker; evaluation of iron-homeostatic markers potential for revealing blood manipulation including analyses of the newly discovered hormone erythroferrone; metabolomics and proteomic analyses.
Thus the project covers a broad range of both well-known and new analytical strategies. Another unique and highly required part of the proposed project, is addressing if gender should be taken into account when interpreting fluctuations of existing and novel markers of blood volume manipulation.
With the present study we were able to demonstrate that the inclusion of the iron regulatory hormones, hepcidin and erythroferrone, can aid in the Athlete Biological Passport in the indirect detection of a small volume autologous blood transfusion. Our results demonstrate that erythroferrone, and to some extent hepcidin, may hold promise but intra-individual variability is of concern and additional studies are required. Furthermore, we demonstrate that small, frequent doses of recombinant human erythropoietin (rHuEPO) treatment administered intravenously provides sufficient erythropoietic response to increase aerobic-dominated performance. We investigated the potential of immature reticulocyte fraction (IRF) and the ratio between immature reticulocyte and red blood cells (IR/RBC) as novel biomarkers for rHuEPO treatment. With this study we demonstrate that a low dose rHuEPO treatment alters IRF and IR/RBC compared with placebo, and that such changes can aid in the indirect detection of rHuEPO misuse. When combining the current markers in the ABP with IRF and IR/RBC ~79% of the rHuEPO treated subjects were flagged at least once.