gsk1278863 and Hypoxia

Daprodustat is a hypoxia-inducible factor prolyl hydroxylase domain (HIF-PHD) inhibitor and is used as an erythropoiesis stimulant for the treatment of anemia in humans. In general, administering daprodustat to horses will result in a lifetime ban from both equestrian sports and horseracing by the International Federation of Horseracing Authorities and the Fédération Équestre Internationale, respectively. To control the misuse/abuse of daprodustat, we conducted nasoesophageal administration of daprodustat (100 mg/day for 3 days) to three thoroughbred mares and the post-administration hair samples collected from the three horses over 6 months were analyzed to demonstrate the potential longer-term detection of daprodustat and its metabolites in hair compared with the detection times of daprodustat of 1 and 2 weeks in plasma and urine respectively. The results of the quantitative 2-cm segmental analysis showed that daprodustat was primarily localized in the proximal region (0-2 cm) at 0.375-0.463 pg/mg at 1 month post-administration. These drug bands were gradually spread out along the hair shaft at a rate consistent with the reported growth rate of horse mane hair (approximately 2.5 cm/month) over the following 6 months. In addition, to attain deeper insight into the mechanism of drug incorporation into hair, a total of 11 relevant parameters, including the actual PK parameters and simulated physicochemical and biopharmaceutical parameters for three HIF stabilizers (i.e., daprodustat, vadadustat, and IOX4), were investigated after normalization of the z-scores of all these parameters. Multiple regression analysis indicated that the major factors contributing to the incorporation of the three drugs into hair were their maximum plasma concentrations and lipophilicities, strongly suggesting that the three HIF stabilizers permeated from the bloodstream into the hair bulb via passive transfer with concentration gradients. This work is the first reported evidence showing the incorporation of HIF stabilizers into hair via passive transfer. In addition, cross-species comparison of drug incorporations into hair between daprodustat in horse and roxadustat in human was made in order to have a better understanding of the interactive interpretations about the analysis results obtained from different species. The above findings are not only useful and beneficial for the purpose of doping control but also provide a better understanding of the mechanism of drug incorporati

Topics: Anemia; Animals; Barbiturates; Female; Hair; Horses; Humans; Hypoxia; Hypoxia-Inducible Factor-Proline Dioxygenases

Performance-enhancing substances and methods have become a serious problem in competitive sports. The hypoxia-inducible factor (HIF) stabilizers can enhance the organism's capacity for molecular oxygen transport and are likely to be abused as performance-enhancing agents in sports. This paper describes the metabolic conversion of the popular hypoxia inducible factor-prolyl hydroxylase (HIF-PH) inhibitors, namely, daprodustat, desidustat, and vadadustat using equine liver microsomes, determined on a QExactive high-resolution mass spectrometer. During this study, a total of 10 metabolites for daprodustat (all are Phase I), 10 metabolites for desidustat (five each for Phase I and Phase II), and 15 metabolites for vadadustat (six for Phase I and nine for Phase II) were detected. The important findings of the current research are as follows: (1) All the three HIF-PH inhibitor drug candidates are prone to oxidation, which results in corresponding hydroxylated metabolites; (2) in desidustat, hydrolysis and dissociation of oxime linkage also observed; (3) the glucuronic acid conjugate (except daprodustat) of the parent drugs as well as the monohydroxylated analogs were observed; (4) sulfonic acid conjugated metabolites were observed only for vadadustat.

Topics: Animals; Barbiturates; Doping in Sports; Glycine; Horses; Hypoxia; Picolinic Acids; Prolyl-Hydroxylase Inhibitors; Quinolones

Topics: Anemia; Barbiturates; Cell Hypoxia; Glycine; Humans; Hypoxia; Renal Insufficiency, Chronic

Chronic Cyclosporine-A treatment is associated with serious side effects, including kidney toxicity and anemia. Although pathophysiology of Cyclosporine-A-induced kidney injury remains incompletely understood, hypoxia is likely involved. Here, we investigated the effect of the hypoxia inducible factor activator daprodustat on Cyclosporine-A -induced kidney toxicity. As Cyclosporine-A profoundly alters protein phosphorylation by inhibiting the phosphatase calcineurin, special attention was directed towards the kidney phospho-proteome. Mice received Cyclosporine-A with or without daprodustat for up to eight weeks. In kidney homogenates, 1360 selected proteins were analyzed at expression and phosphorylation levels. Of these, Cyclosporine-A changed the expression of 79 and the phosphorylation of 86 proteins. However, when Cyclosporine-A treatment was combined with daprodustat, the expression of 95 proteins and phosphorylation of only six proteins was altered suggesting that daprodustat prevented most protein phosphorylation brought about by Cyclosporine-A. Although daprodustat showed only marginal effect on its own, angiogenesis-related pathways were among the most profoundly impacted by daprodustat when given on top of Cyclosporine-A. Additionally, Cyclosporine-A lowered the blood hemoglobin concentration and caused kidney capillary rarefaction, which daprodustat prevented. Thus, combined daprodustat/Cyclosporine-A treatment prevented deleterious Cyclosporine-A effects on microcirculation and hemoglobin, and the protective action of daprodustat involves suppression of broad protein phosphorylation changes caused by Cyclosporine-A.

Topics: Anemia; Animals; Barbiturates; Calcineurin; Cyclosporine; Glycine; Hemoglobins; Hypoxia; Mice; Proteome