Intolerability of cobalt salt as erythropoietic agent

Coordination chemistry applied to anti-doping analysis: Cobalt quantification as its diethyldithiocarbamate complex by liquid chromatography coupled to high resolution tandem mass spectrometry

Cobalt was included on the World Anti-Doping Agency Prohibited List in 2015 due to its effect on stimulus of erythropoiesis via stabilization of hypoxia-inducible factor. Although it has proven benefits for performance enhancement, the unavailability of inductively coupled plasma-mass spectrometry on routine of the accredited laboratories is a factor that reduces its applicability in anti-doping analysis. Therefore, an analytical method for quantification of urinary cobalt as its diethyldithiocarbamate complex by liquid chromatography coupled with high-resolution tandem mass spectrometry was developed and validated. Palladium was proposed as internal standard and rhodium as a complexation control. A microwave-assisted acid digestion of the urine samples was essential, not only to eliminate the matrix effect but mainly to avoid the non-specific bond of cobalt to endogenous molecules. A linear method was obtained over the studied range from a negative urine control to a spiked concentration of 25 ng/mL, with an estimated limit of quantification of 2.5 ng/mL, and an adequate combined standard uncertainty of 11.4%. Considering that all reagents are commercially available, the proposed strategy is feasible to be included on routine sample preparation. Monitoring urinary cobalt concentrations globally opens the perspective to support the anti-doping system to define a suitable threshold value and to understand its potential misuse by athletes seeking for performance improvement.

Cardiovascular effects of doping substances, commonly prescribed medications and ergogenic aids in relation to sports: a position statement of the sport cardiology and exercise nucleus of the European Association of Preventive Cardiology

The use of substances and medications with potential cardiovascular effects among those practicing sports and physical activity has progressively increased in recent years. This is also connected to the promotion of physical activity and exercise as core aspects of a healthy lifestyle, which has led also to an increase in sport participation across all ages. In this context, three main users' categories can be identified, (i) professional and amateur athletes using substances to enhance their performance, (ii) people with chronic conditions, which include physical activity and sport in their therapeutic plan, in association with prescribed medications, and (iii) athletes and young individuals using supplements or ergogenic aids to integrate their diet or obtaining a cognitive enhancement effect. All the substances used for these purposes have been reported to have side effects, among whom the cardiovascular consequences are the most dangerous and could lead to cardiac events. The cardiovascular effect depends on the type of substance, the amount, the duration of use, and the individual response to the substances, considering the great variability in responses. This Position Paper reviews the recent literature and represents an update to the previously published Position Paper published in 2006. The objective is to inform physicians, athletes, coaches, and those participating in sport for a health enhancement purpose, about the adverse cardiovascular effects of doping substances, commonly prescribed medications and ergogenic aids, when associated with sport and exercise.

Circulating MicroRNAs as a New Class of Biomarkers of Physiological Reactions of the Organism to the Intake of Dietary Supplements and Drugs

BACKGROUND

The analysis of individual microRNAs (miRNAs) as a diagnostic and prognostic tool for the effective treatment of various diseases has aroused particular interest in the scientific community. The determination of circulating miRNAs makes it possible to assess biological changes associated with nutritional processes, the intake of dietary supplements and drugs, etc. The profile of circulating miRNAs reflects the individual adaptation of the organism to the effect of specific environmental conditions.

OBJECTIVE

The objective of this study is to systematize the data and show the importance of circulating miRNAs as new potential biomarkers of the organism's response to the intake of various dietary supplements, drugs, and consider the possibility of their use in doping control.

METHODS

A systematic analysis of scientific publications (ncbi.nlm.nih.gov) on the miRNA expression profile in response to the intake of dietary supplements and drugs most often used by athletes, and supposed their role as potential markers in modern doping control was carried out.

RESULTS

The profile of circulating miRNAs is highly dependent on the intake of a particular drug, and, therefore, may be used as a marker of the effects of biologically active supplements and drugs including the substances from the Prohibited List of the World Anti-Doping Agency (WADA).

CONCLUSION

Monitoring of circulating miRNAs can serve as a high-precision marker for detecting doping abuse in elite sports. However, it is necessary to conduct additional studies on the effect of complex drugs on the profile of circulating miRNAs and individual circulating miRNAs on a particular biological process.

Effects on white blood cell counts and the NLRP3 inflammasome due to dust and cobalt exposure in the hard metal industry

INTRODUCTION

In light of potential negative health effects of cobalt exposure, a characterization of inflammatory mechanisms in exposed individuals is warranted. The current study investigated cobalt exposure in the Swedish hard metal industry and its relationship to inflammatory markers, including NLRP3 inflammasome activation and white blood cell (WBC) counts.

MATERIALS AND METHODS

Inhalable cobalt and dust exposures, and systemic cobalt levels, were determined for 72 workers in the hard metal industry and linear regression models were applied to correlate exposure to markers of inflammasome activation and WBC counts.

RESULTS

Mean exposures to inhalable dust (0.11 mg/m³) and cobalt (0.0034 mg/m³) were below the Swedish occupational exposure limits, and these low exposures did not correlate with any investigated outcomes. Instead, cobalt blood levels significantly correlated with a ca 10% decrease in IL-18 plasma levels per 10 nM cobalt increase. Furthermore, pre-shift cobalt blood and/or urine levels significantly correlated with some WBC measures, including decreased neutrophil-to-lymphocyte ratio, increased lymphocyte-to-monocyte ratio, and lymphocyte counts.

CONCLUSION

The low inhalable particle exposures had no impact on WBC counts and inflammasome activation. Instead, systemic cobalt levels, which also include skin exposure, demonstrated possible suppressive effects on inflammatory responses in cobalt-exposed individuals in the hard metal industry.

Study of cobalt doping control via various routes in thoroughbred horses

Cobalt is a substance that has been abused for athletic performance enhancement and has thus been prohibited by human and animal sports doping control authorities. However, because cobalt is present in humans and animals as a trace element, a certain level of cobalt is naturally present in their excretions. In the racing industry, cobalt is a controlled substance with a threshold concentration specified by the International Agreement on Breeding, Racing and Wagering (IABRW) for international harmonization. Due to environmental and feed consumption differences among countries, regional cobalt concentration trends should be evaluated before cobalt testing is introduced. In this study, we conducted a preliminary evaluation of the urinary concentration of cobalt among a population of racehorses in Korea using inductively coupled plasma mass spectrometry (ICP-MS) analysis, followed by analysis of the urinary release of cobalt after the administration of cobalt chloride in various situations. The normal distribution for the Korea-based racehorses was used to determine a urine concentration limit (96.5 ng/ml, risk factor of 1 in 10,000). After the intravenous (IV) administration of CoCl₂ , the initial elimination of cobalt was rapid. A high concentration (over 2,000 ng/ml) and a slow excretion pattern were observed during the final 2 weeks of the 3-week observation period. When CoCl₂ was administered orally, maximum concentration (C_max , 92-992 ng/ml) was observed at 6-8 h.

Genotoxicity of chromium (III) and cobalt (II) and interactions between them

Introduction. Chromium and cobalt are essential trace elements that are required only in a small amount, otherwise their excess can cause toxic effects.

Aim. The aim of this study was to determine the effects of chromium (III) and cobalt (II) and their combinations on genotoxicity in human fibroblasts cells (BJ).

Material and methods. In this work, comet and micronucleus assays were used. The BJ cells were exposed to chromium chloride and cobalt chloride at concentration ranges from 100 to 1400 µM. Mixtures of these elements were prepared so as to examine interactions between them.

Results. The present study shows the genotoxic effects of chromium (III) and cobalt (II) and their mixtures on BJ cells. In the comet assay, no comets were observed at the lowest concentrations; in the higher, a significant increase in their percentage was observed. In the other assay (formation of micronuclei), a statistically significant increase in the number of cells with micronuclei was observed in the BJ cells spiked with cobalt chloride and chromium chloride. In the case of simultaneous incubation of chromium chloride at 200 µM and cobalt chloride at 1000 µM in the BJ line, antagonism was observed. However, the interaction of chromium chloride at the 1000 µM and cobalt chloride at 200 µM leads to synergism between the studied elements.

Conclusions. Cobalt (II) and chromium (III) show genotoxic properties, they induce breaks in double and single-stranded DNA and they cause formation of AP-sites that do not have purine or pyrimidine bases.

Arrhythmogenic right ventricular cardiomyopathy and sports activity: from molecular pathways in diseased hearts to new insights into the athletic heart mimicry

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is an inherited disease associated with a high risk of sudden cardiac death. Among other factors, physical exercise has been clearly identified as a strong determinant of phenotypic expression of the disease, arrhythmia risk, and disease progression. Because of this, current guidelines advise that individuals with ARVC should not participate in competitive or frequent high-intensity endurance exercise. Exercise-induced electrical and morphological para-physiological remodelling (the so-called 'athlete's heart') may mimic several of the classic features of ARVC. Therefore, the current International Task Force Criteria for disease diagnosis may not perform as well in athletes. Clear adjudication between the two conditions is often a real challenge, with false positives, that may lead to unnecessary treatments, and false negatives, which may leave patients unprotected, both of which are equally inacceptable. This review aims to summarize the molecular interactions caused by physical activity in inducing cardiac structural alterations, and the impact of sports on arrhythmia occurrence and other clinical consequences in patients with ARVC, and help the physicians in setting the two conditions apart.

Quantification of cobalt and nickel in urine using inductively coupled plasma atomic emission spectroscopy

Cobalt and nickel are micronutrients indispensable for the body, therefore, their use with food or as part of vitamin complexes is necessary to maintain health. As a result, trace cobalt and nickel contents are present in human biological fluids - blood and urine. According to the World Anti-Doping Agency prohibited list, they belong to the group of blood doping preparations - erythropoiesis stimulants. Nowadays, methods for their control in biological fluids are being actively developed to establish reasonable allowable contents of these trace elements in human biological fluids. However, in addition to developing highly sensitive methods for the determination of the total content of cobalt and nickel using ICP-MS and ETAAS, the development and comparison of various sample preparation methods that can provide the greatest accuracy, reproducibility and express analysis are also relevant. In the present paper, a comparison of different sample preparation methods - direct analysis, dilution and microwave mineralization of urine samples was shown, the detection and quantification limits were compared, some metrological characteristics that can be achieved using these sample preparation methods were evaluated. The procedure was tested on artificial and real urine samples. Taking the course of vitamin complexes in therapeutic concentrations was shown not to lead to a significant increase in the concentrations of analytes in urine, while taking elevated concentrations (for example, 2-fold) makes it possible to determine them even using ICP-AES. However, even in this case, cobalt and nickel concentrations remain at a relatively low level, not able to lead to a significant increase in erythropoiesis.

Doping detection in animals: A review of analytical methodologies published from 1990 to 2019

Despite the impressive innate physical abilities of horses, camels, greyhounds, or pigeons, doping agents might be administered to these animals to improve their performance. To control these illegal practices, anti-doping analytical methodologies have been developed. This review compiles the analytical methods that have been published for the detection of prohibited substances administered to animals involved in sports over 30 years. Relevant papers meeting the search criteria that discussed analytical methods aiming to detect and/or quantify doping substances in animal biological matrices published from 1990 to 2019 were considered. A total of 317 studies were included, of which 298 were related to horses, demonstrating significant advances toward the development of doping detection methods for equine sports. However, analytical methods for the detection of doping agents in sports involving other species are lacking. Due to enhanced accuracy and specificity, chromatographic analysis coupled to mass spectrometry detection is preferred over immunoassays. Regarding biological matrices, blood and urine remain the first choice, although alternative biological matrices, such as hair and feces, have been considered. With the increasing number and type of drugs used as doping agents, the analytes addressed in the published papers are diverse. It is very important to continue to detect and quantify these drugs, recognizing those that are most frequently used, in order to punish the abusers, protect animals' health, and ensure a healthier and genuine competition.

Measurement of urinary cobalt as its complex with 2-(5-chloro-2-pyridylazo)-5-diethylaminophenol by liquid chromatography-tandem mass spectrometry for the purpose of anti-doping control

Cobalt is well known for its ability to stimulate erythropoiesis via stabilization of hypoxia-inducible factors. In sports, this can provide a competitive benefit to athletes, so the World Anti-Doping Agency prohibits the use of cobalt in any form except its cobalamin vitamers. As of now, cobalt in biological fluids is detected by inductively coupled plasma mass spectrometry (ICP-MS), a technique which has very limited availability in anti-doping laboratories. Therefore, a quantitative method based on liquid chromatography-tandem mass spectrometry capable of measuring urinary cobalt in the form of its complex with 2-(5-chloro-2-pyridylazo)-5-diethylaminophenol (5-Cl-PADAP) has been developed and validated. A cobalt complex with deuterium-labeled 5-Cl-PADAP was used as internal standard. The method was found linear over the concentration range of 5-500 ng/ml with a combined standard uncertainty less than 10% at 15, 200, and 450 ng/ml. Stability of cobalt ions in urine was investigated over the course of 2 months; the concentration of free Co²⁺ was observed to decline by approximately 50% but restored upon hydrolysis with hydrochloric acid. Unlike ICP-MS, this method is practically unaffected by the presence of cyanocobalamin as the latter is resistant to acid hydrolysis. Notwithstanding the lack of formalized threshold concentration of cobalt in urine, it is highly desirable that more anti-doping laboratories engage in testing for cobalt levels to better understand the prevalence of cobalt misuse in athletes. Given that cobalt salts are inexpensive and easily obtainable, the risk of such abuse should not be underestimated.

Systemic Effects of Metals Released from Arthroplasty Implants – a Brief Summary

In recent years, increasing concern has been raised regarding potential systemic toxicity of metals released from arthroplasty implants. A lack of valid metal thresholds for human (organ) toxicity and the prospect of multi-decade survival of modern hip and knee replacements pose special challenges. Indeed, evidence of systemic effects of metals released from such implants is largely missing. Systemic cobalt exposure has repeatedly been associated with cardiotoxic and neurotoxic effects, and also with thyroid dysfunction. The toxic potential of chromium is considered less pronounced. Yet, in arthroplasty there is usually a co-exposure to chromium and cobalt which complicates evaluation of element-specific effects. Toxicity of titanium dioxide nanoparticles has been subject to debate among international regulatory authorities. Their wide use in a variety of products in everyday life, such as toothpaste, cosmetics and food colorants, hampers the assessment of an arthroplasty-induced systemic titanium exposure. To date there is no clear evidence for systemic complications due to titanium dioxide released from arthroplasty implants. Release of further metals such as tantalum, niobium, nickel, vanadium and zirconium from hip and knee replacement implants has been described occasionally, but systemic effects of respective long-term exposure scenarios are unknown. Generally, the characterization of all released metals regarding their chemical and physical specifications is critical for the evaluation of potential systemic risks. Systematic studies investigating the accumulation of metals relevant in arthroplasty in different organs/organ systems and the biological consequences of such accumulations are urgently needed.

Cobalt-containing dust exposures: Prediction of whole blood and tissue concentrations using a biokinetic model

Biokinetic models estimating cobalt (Co) tissue burden can help assess the potential for systemic effects. Such models, however, have not been used to estimate remote tissue concentrations associated with inhalation exposure to Co-containing dust in general environments, work spaces, or animal toxicity tests. We have therefore updated a Co biokinetic model previously developed for oral dosing to include the inhalation pathway by incorporating the International Commission on Radiological Protection (ICRP) Human Respiratory Tract Model. Further, data from animal studies allowed for characterization of testes Co tissue concentration supplementing previous predictions for the liver, heart and blood. Reasonable agreement (within a factor of two) was found between modeled and measured blood, liver, testes and tissue concentrations when animal doses were modeled using human equivalent concentrations to account for species differences in regional lung deposition. We applied the updated model to occupational inhalation exposure scenarios, and found that upper-bound plausible human systemic body burden associated with Co ingestion is much higher than the burden associated with Co inhalation. Chronic ingestion of Co at a previously proposed oral reference dose (RfD) of 0.03 mg/kg-day resulted in predicted tissue levels of 22-54 μg/L (blood), 0.05-0.1 μg/g (heart), 0.01-0.02 μg/g (testes), and 0.2-0.5 μg/g (liver), which were at least 5-fold more than the systemic burden associated with various Co inhalation occupational exposure limits (OELs) of 0.1 mg/m³ or less (for 8 h/d and 5 d/w). Overall, our analysis indicated that Co-metal or dust induced systemic health effects, including myocardial damage, are unlikely for the inhalation pathway when personal exposures levels are below concentrations associated with local respiratory effects such as pulmonary fibrosis.

Review of WADA Prohibited Substances: Limited Evidence for Performance-Enhancing Effects

The World Anti-Doping Agency is responsible for maintaining a Prohibited List that describes the use of substances and methods that are prohibited for athletes. The list currently contains 23 substance classes, and an important reason for the existence of this list is to prevent unfair competition due to pharmacologically enhanced performance. The aim of this review was to give an overview of the available evidence for performance enhancement of these substance classes. We searched the scientific literature through PubMed for studies and reviews evaluating the effects of substance classes on performance. Findings from double-blind, randomized controlled trials were considered as evidence for (the absence of) effects if they were performed in trained subjects measuring relevant performance outcomes. Only 5 of 23 substance classes show evidence of having the ability to enhance actual sports performance, i.e. anabolic agents, β2-agonists, stimulants, glucocorticoids and β-blockers. One additional class, growth hormone, has similar evidence but only in untrained subjects. The observed effects all relate to strength or sprint performance (and accuracy for β-blockers); there are no studies showing positive effects on reliable markers of endurance performance. For 11 classes, no well-designed studies are available, and, for the remaining six classes, there is evidence of an absence of a positive effect. In conclusion, for the majority of substance classes, no convincing evidence for performance enhancement is available, while, for the remaining classes, the evidence is based on a total of only 266 subjects from 11 studies.

Hypoxia-Inducible Factor Activators in Renal Anemia: Current Clinical Experience

Prolyl hydroxylase domain oxygen sensors are dioxygenases that regulate the activity of hypoxia-inducible factor (HIF), which controls renal and hepatic erythropoietin production and coordinates erythropoiesis with iron metabolism. Small molecule inhibitors of prolyl hydroxylase domain dioxygenases (HIF-PHI [prolyl hydroxylase inhibitor]) stimulate the production of endogenous erythropoietin and improve iron metabolism resulting in efficacious anemia management in patients with CKD. Three oral HIF-PHIs-daprodustat, roxadustat, and vadadustat-have now advanced to global phase III clinical development culminating in the recent licensing of roxadustat for oral anemia therapy in China. Here, we survey current clinical experience with HIF-PHIs, discuss potential therapeutic advantages, and deliberate over safety concerns regarding long-term administration in patients with renal anemia.

Effects of 3 Weeks of Oral Low-Dose Cobalt on Hemoglobin Mass and Aerobic Performance

Introduction: Cobalt ions (Co²⁺) stabilize HIFα and increase endogenous erythropoietin (EPO) production creating the possibility that Co²⁺ supplements (CoSupp) may be used as performance enhancing substances. The aim of this study was to determine the effects of a small oral dosage of CoSupp on hemoglobin mass (Hbmass) and performance with the objective of providing the basis for establishing upper threshold limits of urine [Co²⁺] to detect CoSupp misuse in sport.

Methods: Twenty-four male subjects participated in a double-blind placebo-controlled study. Sixteen received an oral dose of 5 mg of ionized Co²⁺ per day for 3 weeks, and eight served as controls. Blood and urine samples were taken before the study, during the study and up to 3 weeks after CoSupp. Hbmass was determined by the CO-rebreathing method at regular time intervals, and VO_2max was determined before and after the CoSupp administration period.

Results: In the Co²⁺ group, Hbmass increased by 2.0 ± 2.1% (p < 0.001) while all the other analyzed hematological parameters did not show significant interactions of time and treatment. Hemoglobin concentration ([Hb]) and hematocrit (Hct) tended to increase (p = 0.16, p = 0.1) and also [EPO] showed a similar trend (baseline: 9.5 ± 3.0, after 2 weeks: 12.4 ± 5.2 mU/ml). While mean VO_2max did not change, there was a trend for a positive relationship between changes in Hbmass and changes in VO_2max immediately after CoSupp (r = 0.40, p = 0.11). Urine [Co²⁺] increased from 0.4 ± 0.3 to 471.4 ± 384.1 ng/ml (p < 0.01) and remained significantly elevated until 2 weeks after cessation.

Conclusion: An oral Co²⁺ dosage of 5 mg/day for 3 weeks effectively increases Hbmass with a tendency to increase hemoglobin concentration ([Hb]) and hematocrit (Hct). Because urine Co²⁺ concentration remains increased for 2 weeks after cessation, upper limit threshold values for monitoring CoSupp can be established.

Effects of erythropoietin abuse on exercise performance

The present review provides a comprehensive overview on the erythropoietic and non-erythropoietic effects of rHuEpo on human sport performance, paying attention to quantifying numerically how rHuEpo affects exercise performance and describing physiological changes regarding the most important exercise variables. Much attention has been paid to treatment schedules, in particular, to assess the effects of microdoses of rHuEpo and the prolonged effects on sport performance following withdrawal. Moreover, the review takes into account non-erythropoietic ergogenic effects of rHuEpo, including cognitive benefits of rHuEpo. A significant increase in both Vo2max and maximal cycling power was evidenced in studies taken into account for this review. rHuEpo, administered at clinical dosage, may have significant effects on haematological values, maximal and submaximal physiological variables, whereas few reports show positive effects on exercise perfomance. However, the influence of micro-dose rHuEpo on endurance performance in athletes is still unclear and further studies are warranted.

Cardiovascular Effects of Performance-Enhancing Drugs

Exercise and competitive sports should be associated with a wide range of health benefits with the potential to inspire a positive community health legacy. However, the reputation of sports is being threatened by an ever-expanding armamentarium of agents with real or perceived benefits in performance enhancement. In addition to the injustice of unfair advantage for dishonest athletes, significant potential health risks are associated with performance-enhancing drugs. Performance-enhancing drugs may have an effect on the cardiovascular system by means of directly altering the myocardium, vasculature, and metabolism. However, less frequently considered is the potential for indirect effects caused through enabling athletes to push beyond normal physiological limits with the potential consequence of exercise-induced arrhythmias. This review will summarize the known health effects of PEDs but will also focus on the potentially greater health threat posed by the covert search for performance-enhancing agents that have yet to be recognized by the World Anti-Doping Agency. History has taught us that athletes are subjected to unmonitored trials with experimental drugs that have little or no established efficacy or safety data. One approach to decrease drug abuse in sports would be to accept that there is a delay from when athletes start experimenting with novel agents to the time when authorities become aware of these drugs. This provides a window of opportunity for athletes to exploit with relative immunity. It could be argued that all off-label use of any agent should be deemed illegal.

Nickel in equine sports drug testing - pilot study results on urinary nickel concentrations

RATIONALE

The issue of illicit performance enhancement spans human and animal sport in presumably equal measure, with prohibited substances and methods of doping conveying both ways. Due to the proven capability of unbound ionic cobalt (Co(2) (+) ) to stimulate erythropoiesis in humans, both human and equine anti-doping regulations have listed cobalt as a banned substance, and in particular in horse drug testing, thresholds for cobalt concentrations applying to plasma and urine have been suggested or established. Recent reports about the finding of substantial amounts of undeclared nickel in arguably licit performance- and recovery-supporting products raised the question whether the ionic species of this transition metal (Ni(2) (+) ), which exhibits similar prolyl hydroxylase inhibiting properties to Co(2) (+) , has been considered as a substitute for cobalt in doping regimens.

METHODS

Therefore, a pilot study with 200 routine post-competition doping control horse urine samples collected from animals participating in equestrian, gallop, and trotting in Europe was conducted to provide a first dataset on equine urinary Ni(2) (+) concentrations. All specimens were analyzed by conventional inductively coupled plasma mass spectrometry (ICP-MS) to yield quantitative data for soluble nickel.

RESULTS

Concentrations ranging from below the assay's limit of quantification (LOQ, 0.5 ng/mL) up to 33.4 ng/mL with a mean value (± standard deviation) of 6.1 (±5.1) ng/mL were determined for the total nickel content.

CONCLUSIONS

In horses, nickel is considered a micronutrient and feed supplements containing nickel are available; hence, follow-up studies are deemed warranted to consolidate potential future threshold levels concerning urine and blood nickel concentrations in horses using larger sets of samples for both matrices and to provide in-depth insights by conducting elimination studies with soluble Ni(2) (+) -salt species. Copyright © 2016 John Wiley & Sons, Ltd.

Cobalt use and regulation in horseracing: a review

Cobalt, atomic weight 58.9, is a metallic element and environmental substance found in the animal in microgram quantities, predominantly as vitamin B12, but is also a component of at least one mammalian enzyme unassociated with B12. Cobalt is a required trace mineral and has long been administered as a dietary supplement to humans and animals. Cobalt deficiency outside of its requirement in vitamin B12 has not been reported in humans. The administration of cobalt salts was once standard treatment for anaemia in humans, owing to its ability to stimulate red blood cell synthesis. Elemental cobalt acts by stabilising hypoxia inducible factor (HIF-1α), which activates the erythropoietin gene, which in turn increases haemoglobin/red blood cell synthesis, which had led to a presumption that cobalt may be performance enhancing in athletes. Administration of cobalt in amounts sufficient to significantly increase the haematocrit are associated with risk of toxicity in humans, and the only cobalt administration study in horses showed no effect on red blood cell parameters or toxicity. Because of the perception that cobalt administration may enhance athletic performance, racing regulators have recently begun to restrict cobalt use in horseracing which has led to the introduction of cobalt thresholds in several racing jurisdictions. The International Federation of Horseracing Authorities is considering an international regulatory threshold for cobalt of 100 ng/ml in urine, based on studies performed in five different countries. In the United States, the Racing Commissioners International has recently set a primary plasma threshold of 25 ng/ml and secondary threshold of 50 ng/ml. One New York and New Jersey racetrack owner has initiated testing for cobalt and has denied his facilities to trainers whose horses tested positive for excessive quantities of cobalt. This review seeks to summarise what is known about the use of cobalt in horse racing.

Anaemia in kidney disease: harnessing hypoxia responses for therapy

Improved understanding of the oxygen-dependent regulation of erythropoiesis has provided new insights into the pathogenesis of anaemia associated with renal failure and has led to the development of novel therapeutic agents for its treatment. Hypoxia-inducible factor (HIF)-2 is a key regulator of erythropoiesis and iron metabolism. HIF-2 is activated by hypoxic conditions and controls the production of erythropoietin by renal peritubular interstitial fibroblast-like cells and hepatocytes. In anaemia associated with renal disease, erythropoiesis is suppressed due to inadequate erythropoietin production in the kidney, inflammation and iron deficiency; however, pharmacologic agents that activate the HIF axis could provide a physiologic approach to the treatment of renal anaemia by mimicking hypoxia responses that coordinate erythropoiesis with iron metabolism. This Review discusses the functional inter-relationships between erythropoietin, iron and inflammatory mediators under physiologic conditions and in relation to the pathogenesis of renal anaemia, as well as recent insights into the molecular and cellular basis of erythropoietin production in the kidney. It furthermore provides a detailed overview of current clinical experience with pharmacologic activators of HIF signalling as a novel comprehensive and physiologic approach to the treatment of anaemia.