Detection of prohibited growth factors (GFs) in doping control: serum concentration ranges in a reference population of athletes

Abstract

Growth factors (GFs) are a wide class of polypeptides that can regulate cellular proliferation, migration and differentiation. Due to their ability to extensively impact on tissue regeneration, the use of GFs in sports is currently prohibited in and out of competition and included in the 2022 List of Prohibited Substances of the World Anti‐Doping Agency (WADA). At present, methods of detection of prohibited GFs for doping control purposes have been developed exclusively for recombinant Growth Hormone (recGH) and Insulin‐like growth factor1 (IGF‐1).Since GFs are endogenously produced substances, their abuse can be detected by fixing “reporting threshold” to differentiate their normal, physiological levels and the exogenous administration. Such a strategy imposes the determination of “normality ranges” for the athletic population.We considered the principal banned GFs, that are fibroblast growth factor (FGF), platelet‐derived growth factor (PDGF), vascular endothelial growth factor (VEGF), and hepatocyte growth factor (HGF), measuring their levels – including those of their major isoforms – in 92 serum samples, collected from elite athletes in the framework of doping control tests. Preliminarily, we confirmed all the above considered growth factors are actually measurable in serum, defining also their respective limits of detection. Furthermore, we were able to identify differences in concentration levels possibly related to gender and age. Finally, we established normal serum concentration ranges, that can be used as reference normal population values necessary to fix threshold values able to discriminate the physiological levels and the recourse of doping practices.