Recombinant human erythropoietin (rhEPO) is prohibited by the World Anti‐Doping Agency. rhEPO abuse can be indirectly detected via the athlete biological passport (ABP). However, altitude exposure challenges interpretation of the ABP. This study investigated whether 5′‐aminolevulinate synthase 2 (ALAS2) and carbonic anhydrase 1 (CA1) in capillary dried blood spots (DBSs) are sensitive and specific markers of rhEPO treatment at altitude. ALAS2 and CA1 expression was monitored in DBS collected weekly before, during, and after a 3‐week period at sea level or altitude. Participants were randomly assigned to receive 20 IU kg bw−1 epoetin alpha (rhEPO) or placebo injections every second day for 3 weeks while staying at sea level (rhEPO, n = 25; placebo, n = 9) or altitude (rhEPO, n = 12; placebo, n = 27). ALAS2 and CA1 expression increased up to 300% and 200%, respectively, upon rhEPO treatment at sea‐level and altitude (P‐values <0.05). When a blinded investigator interpreted the results, ALAS2 and CA1 expression had a sensitivity of 92%. Altitude did not confound the interpretation. Altitude affected ALAS2 and CA1 expression less than actual ABP markers when compared between sea level and altitude results. An individual athlete passport‐like approach simulation confirmed the biomarker potential of ALAS2 and CA1. ALAS2 and CA1 were sensitive and specific biomarkers of micro‐dose rhEPO treatment at sea level and altitude. Altitude seemed less a confounding factor for these biomarkers, especially when they are combined. Thus, micro‐dose rhEPO injections can be detected in a longitudinal blinded setting using mRNA biomarkers in DBS.

中文翻译：

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对海平面和海拔高度的微剂量促红细胞生成素治疗敏感且特异的 mRNA 生物标志物

重组人促红细胞生成素 (rhEPO) 被世界反兴奋剂机构禁止。rhEPO滥用可以通过运动员生物护照（ABP）间接检测到。然而，海拔高度暴露对 ABP 的解释提出了挑战。本研究调查了 5'-氨基乙酰丙酸合酶 2（阿拉斯2) 和碳酸酐酶 1 (CA1) 毛细血管干血斑 (DBS) 是高原地区 rhEPO 治疗的敏感且特异的标志物。阿拉斯2和CA1在海平面或海拔 3 周期间之前、期间和之后每周收集 DBS 中的表达进行监测。参与者被随机分配接受 20 IU kg 体重−1阿尔法促红细胞生成素 (rhEPO) 或安慰剂注射，每隔一天注射一次，持续 3 周，同时留在海平面 (rhEPO，n= 25；安慰剂，n= 9) 或海拔 (rhEPO,n= 12；安慰剂，n= 27）。阿拉斯2和CA1在海平面和海拔高度进行 rhEPO 处理后，表达量分别增加了 300% 和 200%（磷‐值<0.05）。当盲法研究人员解释结果时，阿拉斯2和CA1表达的敏感性为 92%。海拔高度并没有混淆解释。受影响的海拔高度阿拉斯2和CA1当海平面和海拔结果进行比较时，表达低于实际 ABP 标记。类似于个人运动员护照的方法模拟证实了生物标志物的潜力阿拉斯2和CA1。阿拉斯2和CA1是在海平面和海拔高度进行微剂量 rhEPO 治疗的敏感且特异的生物标志物。对于这些生物标志物来说，海拔似乎不再是一个混杂因素，尤其是当它们组合在一起时。因此，可以使用 DBS 中的 mRNA 生物标志物在纵向盲法环境中检测微剂量 rhEPO 注射。