Drugs in sport: a scientist-athlete's perspective: from ambition to neurochemistry

Are We Reaching the Limits of Homo sapiens?

Echoing scientific and industrial progress, the Twentieth century was an unprecedented period of improvement for human capabilities and performances, with a significant increase in lifespan, adult height, and maximal physiological performance. Analyses of historical data show a major slow down occurring in the most recent years. This triggered large and passionate debates in the academic scene within multiple disciplines; as such an observation could be interpreted as our upper biological limits. Such a new phase of human history may be related to structural and functional limits determined by long term evolutionary constraints, and the interaction between complex systems and their environment. In this interdisciplinary approach, we call into question the validity of subsequent forecasts and projections through innovative and related biomarkers such as sport, lifespan, and height indicators. We set a theoretical framework based on biological and environmental relevance rather than using a typical single-variable forecasting approach. As demonstrated within the article, these new views will have major social, economical, and political implications.

Has Athletic Performance Reached its Peak?

Limits to athletic performance have long been a topic of myth and debate. However, sport performance appears to have reached a state of stagnation in recent years, suggesting that the physical capabilities of humans and other athletic species, such as greyhounds and thoroughbreds, cannot progress indefinitely. Although the ultimate capabilities may be predictable, the exact path for the absolute maximal performance values remains difficult to assess and relies on technical innovations, sport regulation, and other parameters that depend on current societal and economic conditions. The aim of this literature review was to assess the possible plateau of top physical capabilities in various events and detail the historical backgrounds and sociocultural, anthropometrical, and physiological factors influencing the progress and regression of athletic performance. Time series of performances in Olympic disciplines, such as track and field and swimming events, from 1896 to 2012 reveal a major decrease in performance development. Such a saturation effect is simultaneous in greyhound, thoroughbred, and frog performances. The genetic condition, exhaustion of phenotypic pools, economic context, and the depletion of optimal morphological traits contribute to the observed limitation of physical capabilities. Present conditions prevailing, we approach absolute physical limits and endure a continued period of world record scarcity. Optional scenarios for further improvements will mostly depend on sport technology and modification competition rules.

Mechanisms governing the health and performance benefits of exercise

Humans are considered among the greatest if not the greatest endurance land animals. Over the last 50 years, as the population has become more sedentary, rates of cardiovascular disease and its associated risk factors such as obesity, type 2 diabetes and hypertension have all increased. Aerobic fitness is considered protective for all-cause mortality, cardiovascular disease, a variety of cancers, joint disease and depression. Here, I will review the emerging mechanisms that underlie the response to exercise, focusing on the major target organ the skeletal muscle system. Understanding the mechanisms of action of exercise will allow us to develop new therapies that mimic the protective actions of exercise.

From gene engineering to gene modulation and manipulation: can we prevent or detect gene doping in sports?

During the last 2 decades, progress in deciphering the human gene map as well as the discovery of specific defective genes encoding particular proteins in some serious human diseases have resulted in attempts to treat sick patients with gene therapy. There has been considerable focus on human recombinant proteins which were gene-engineered and produced in vitro (insulin, growth hormone, insulin-like growth factor-1, erythropoietin). Unfortunately, these substances and methods also became improper tools for unscrupulous athletes. Biomedical research has focused on the possible direct insertion of gene material into the body, in order to replace some defective genes in vivo and/or to promote long-lasting endogenous synthesis of deficient proteins. Theoretically, diabetes, anaemia, muscular dystrophies, immune deficiency, cardiovascular diseases and numerous other illnesses could benefit from such innovative biomedical research, though much work remains to be done. Considering recent findings linking specific genotypes and physical performance, it is tempting to submit the young athletic population to genetic screening or, alternatively, to artificial gene expression modulation. Much research is already being conducted in order to achieve a safe transfer of genetic material to humans. This is of critical importance since uncontrolled production of the specifically coded protein, with serious secondary adverse effects (polycythaemia, acute cardiovascular problems, cancer, etc.), could occur. Other unpredictable reactions (immunogenicity of vectors or DNA-vector complex, autoimmune anaemia, production of wild genetic material) also remain possible at the individual level. Some new substances (myostatin blockers or anti-myostatin antibodies), although not gene material, might represent a useful and well-tolerated treatment to prevent progression of muscular dystrophies. Similarly, other molecules, in the roles of gene or metabolic activators [5-aminoimidazole-4-carboxamide 1-β-D-ribofuranoside (AICAR), GW1516], might concomitantly improve endurance exercise capacity in ischaemic conditions but also in normal conditions. Undoubtedly, some athletes will attempt to take advantage of these new molecules to increase strength or endurance. Antidoping laboratories are improving detection methods. These are based both on direct identification of new substances or their metabolites and on indirect evaluation of changes in gene, protein or metabolite patterns (genomics, proteomics or metabolomics).

Changes in mitochondrial function are pivotal in neurodegenerative and psychiatric disorders: how important is BDNF?

The brain is at the very limit of its energy supply and has evolved specific means of adapting function to energy supply, of which mitochondria form a crucial link. Neurotrophic and inflammatory processes may not only have opposite effects on neuroplasticity, but also involve opposite effects on mitochondrial oxidative phosphorylation and glycolytic processes, respectively, modulated by stress and glucocorticoids, which also have marked effects on mood. Neurodegenerative processes show marked disorders in oxidative metabolism in key brain areas, sometimes decades before symptoms appear (Parkinson's and Alzheimer's diseases). We argue that brain-derived neurotrophic factor couples activity to changes in respiratory efficiency and these effects may be opposed by inflammatory cytokines, a key factor in neurodegenerative processes.

Attitudes and motivations of competitive cyclists regarding use of banned and legal performance enhancers

Drug 'doping' and the use of banned performance enhancing products (PEPs) remains an issue in virtually all competitive sports despite penal consequences and known health risks. The lines distinguishing "fair" and "unfair" performance enhancement have become increasingly blurred. Few studies have explored how attitudes towards legal performance enhancers (drugs/substances, diet, and equipment modifications) may influence motivations to use banned PEPs. In the present study, 68 competitive cyclists completed a survey examining the importance of choosing banned and non-banned PEPs using World Anti-Doping Agency (WADA) and Union Cycliste Internationale (UCI) criteria. Results showed that over 60 percent of cyclists used non-banned PEPs while 8 percent used banned PEPs. Health was overall the most important factor in choosing a PEP while apprehension by a doping agency was least important. Mixed- model ANOVA analyses revealed that motivations to use banned PEPs were complex, as the importance of health, violating the sprit of the sport, performance improvement, and getting caught were differentially influenced by PEP legality (p < 0.001) and whether a cyclist endorsed non-banned PEP use (p < 0.001). The importance of winning, sponsorship, and maintaining competitiveness did not influence non-banned PEP use (p > 0.05). Our findings illustrate the multifactorial nature of PEP use/doping attitudes and highlight the unique role that "legal" performance enhancement may plays in influencing banned and/or unethical sports behaviors. Key PointsUse of performance enhancers is high even among non-professional athletesCyclists overall rated "risk to health" as the most important factor in choosing to use a performance enhancing product.Motivations to use banned performance enhancer are complex and are significantly influenced by whether an athlete utilizes "legal" performance enhancers.

The evolving science of detection of 'blood doping'

Blood doping practices in sports have been around for at least half a century and will likely remain for several years to come. The main reason for the various forms of blood doping to be common is that they are easy to perform, and the effects on exercise performance are gigantic. Yet another reason for blood doping to be a popular illicit practice is that detection is difficult. For autologous blood transfusions, for example, no direct test exists, and the direct testing of misuse with recombinant human erythropoietin (rhEpo) has proven very difficult despite a test exists. Future blood doping practice will likely include the stabilization of the transcription factor hypoxia-inducible factor which leads to an increased endogenous erythropoietin synthesis. It seems unrealistic to develop specific test against such drugs (and the copies hereof originating from illegal laboratories). In an attempt to detect and limit blood doping, the World Anti-Doping Agency (WADA) has launched the Athlete Biological Passport where indirect markers for all types of blood doping are evaluated on an individual level. The approach seemed promising, but a recent publication demonstrates the system to be incapable of detecting even a single subject as 'suspicious' while treated with rhEpo for 10-12 weeks. Sad to say, the hope that the 2012 London Olympics should be cleaner in regard to blood doping seems faint. We propose that WADA strengthens the quality and capacities of the National Anti-Doping Agencies and that they work more efficiently with the international sports federations in an attempt to limit blood doping.

Drugs in sport

This themed issue of the British Journal of Pharmacology has been compiled and edited by Ian McGrath, Regius Professor of Physiology at University of Glasgow and David Cowan, Director of the Drug Control Centre at King's College London. It contains 11 articles covering the mechanisms of action of the major groups of drugs used illicitly in sport. The articles, written by experts in how drugs work, set out where drugs can or cannot affect sporting performance, how this relates to their legitimate medicinal use, their other detrimental effects and how they can be detected. Publication coincides with Olympic year, when sport is highlighted in the public mind and much speculation is made concerning the use of drugs. The articles provide a framework of expert, accurate knowledge to inform and facilitate these debates and to help to overcome the ill-informed and dangerous anecdotal information by which sports men and women are persuaded to misuse drugs in the mistaken belief that this will improve their performance without present or future ill effects. A unique article is included by the Spedding brothers, Mike with a long career in drug discovery and Charlie, the 1984 Los Angeles Olympic Marathon Bronze Medallist and still the English National Marathon record holder. From their unique experience, they describe the insidious and unfair way that drug-assisted performance undermines the ethos of sport and endangers the vital place of sport in maintaining the health of the population.