Genetic and protein biomarkers in blood for the improved detection of GH abuse

Abstract

Human Growth Hormone (hGH, somatotropin) is one of the relevant forbidden substances to be detected in sport drug testing. Since the appearance of recombinant hGH (rhGH) in the 80's, its expansion and availability through the black market have increased, so the detection of its abuse continues to be a challenge at present. New techniques or biomarkers that are robust, reliable, sensitive and allowing a large detection time window are welcome. rhGH produces an increase of insulin-like growth factor 1 (IGF-1). FN1 (fibronectin 1) and RAB31 (member of RAS oncogene family) genes have been suggested as two potential biomarkers for IGF-1 abuse. Following this line, in the present study some genetic and proteomic approaches have been performed with fourteen healthy male subjects treated with rhGH (which produces increase of IGF-1 concentrations) to study FN1 gene, FN1 protein, RAB31 gene and RAB31 protein as potential biomarkers for rhGH abuse. The results showed that both, RAB31 and FN1 genes and FN1 protein could be potential biomarkers for rhGH administration. Preliminary assessments of gender, age, acute sport activities and GHRP-2 (pralmorelin, a rhGH releasing peptide) influence suggest they are not relevant confounding factors. Thus, the selected markers present high sensitivity and a larger detection window for rhGH detection than IGF-1 itself.

Evaluation of fibronectin 1 in one dried blood spot and in urine after rhGH treatment

“…The consistency of FN1 concentrations in blood serum or plasma in front of gender, age, and exercise variability had been already indicated by a previous study 9 and DBSs are expected to follow a similar trend. However, such an investigation with an appropriate number of athletes, including females, would be welcome.…”

“…[8,9] FN1 analysis in new matrices, such as DBSs and urine, appears as an alternative to improve logistic problems associated with current blood collection in sports drug testing. [8,9] FN1 analysis in new matrices, such as DBSs and urine, appears as an alternative to improve logistic problems associated with current blood collection in sports drug testing.…”

“…[8,9] Nevertheless, its determination in other matrices is highly welcome due to the potential advantages of these novel biological materials compared to those previously studied. [8,9] Nevertheless, its determination in other matrices is highly welcome due to the potential advantages of these novel biological materials compared to those previously studied.…”

“…The functions of FN1 are related to cell adhesion and migration processes including embryogenesis, wound healing, blood coagulation, and host defence. [8,9] Previous results obtained in this area showed high mRNA expression levels of the FN1 gene after treatment with IGF-1 or rhGH in PBL samples and high FN1 protein levels after low rhGH doses in serum and plasma samples for a sustained time period (at least 7 days after end of rhGH treatment). [2] Largely responsible for the presence of FN1 in plasma is its synthesis by hepatocytes although a smaller contribution by macrophages, lymphocytes, platelets, and endothelial cells is produced.…”

Annual banned‐substance review: analytical approaches in human sports drug testing

“…In addition, aspects of analytical approaches including the so‐called isoform and biomarker tests were discussed and the potential contribution of longitudinal monitoring of selected biomarkers as part of the ABP were argued . Complementary to established test methods, the utility of combining biomarkers from transcriptional and (post)translational level, namely fibronectin 1 (FN1), RAB31, P‐III‐NP, and IGF‐I was assessed . In the course of an administration study with recombinant GH injected at 0.026 mg/kg/day to a total of 10 individuals, a significant increase of mRNA levels of FN1 and RAB31 as well as serum peptide concentrations of FN1 were observed over a period of up to 7 days.…”