Effect Of Low Dose Cobalt Administration On Erythropoiesis

Abstract

Before recombinant EPO became available cobalt chloride has been used as a therapeutic drug to treat anemic patients. Nowadays, cobalt (Co) is offered as nutritional supplement for endurance athletes as it is supposed to stimulate erythropoiesis also in small dosages. As a consequence, WADA has put cobalt on the list of prohibited substances although no information is available on the efficacy of low dose Co application on red cell production. PURPOSE: To evaluate the effect of low dose oral Co administration on erythropoietic activity. METHODS: Three studies were performed: 1. application of a single dose of either 5mg Co (n=6) or 10mg Co (n=7); 2. application of 5mg (n=9) or 10 mg (n=7) per day for 5 days, and 3. application of 5 mg Co/day for 3 weeks followed by a 3-week wash-out period (n=16). In all studies a control group was included. Venous EPO concentration was determined in all studies, reticulocytes (ret%) and immature reticulocyte fraction (IRF) in study 2 and 3 and tHbmass in study 3 by the optimized carbon monoxide re-breathing method. RESULTS: 10 mg Co significantly increased plasma EPO until 7h after the single dose (from 8.7 ±2.6 to 11.5 ±2.4 mU/ml) and after the 5-day administration (from 10.6 ±2.6 to 13.1 ±4.2 mU/ml, p<0.05). 5 mg Co had only a slight effect 5h after a single application (from 8,8 ±4,3 to 10,6 ±5,5 mU/ml, p<0.05). During the 3-week administration 5mg Co transiently increased EPO by 30% (from 9.5 ±3.0 to 12.4 ±5.2 mU/ml after 2 weeks, p=0.01). IRF increased after 5 days of 10mg Co administration (from 0.60 ±0.22 to 0.87 ±0.27, p<0.001), but not after short or long-term dosage of 5 mg. Ret% slightly increased in study 3 after 2 weeks (from 1.16 ±0.42 to 1.25 ±0.41%, p<0.05). In study 3, Hbmass slightly increased until week 2 (+17.2 ±22.1g, p=0.01) and remained at higher level thereafter. CONCLUSIONS: Low dose cobalt administration which can be achieved with nutritional supplements slightly increases erythropietic activity and total hemoglobin mass. Supported by WADA Grant 13D21DS.