N C Craig Sharp
Sports Sciences, Brunel University, London, UK

https://doi.org/10.36866/pn.57.15

Many of the recent Olympic headlines featured aspects of doping, which in essence is the taking of substances, mostly specifically banned by the Olympic Charter, to ‘artificially improve competition performance’. Competitors are not necessarily looking for major performance improvements through doping, because very small increments often make a critical difference in elite sport – as the closeness of the British wins in Athens in the rowing four and the men’s 4 x 100m relay and Kelly Holmes in the 800m, testify. The men’s relay team got home by .01s, the same margin by which Said Aouita in1984 broke David Moorcroft’s 5000m world record of 13min 0.41s. In the latter case, the margin was 0.000013%, less than the accuracy of the track measurement (Sharp, 1999)! Such fine margins provide a strong temptation to resort to doping in the quantified sports. The saddest case among the dozen or so disqualified competitors at Athens was Irina Kozhanenko who ‘won’ the shot-putt, the only event staged in Ancient Olympia, before 18,000 spectators. However, she tested positive for the anabolic steroid stanozolol – the same drug that Ben Johnson had taken 16 years before. The first world anti-doping conference, in Lausanne in 1999, stimulated by the doping debacle of the 1998 Tour de France when the entire Festina team was disqualified, led to the world anti-doping agency (WADA) being set up, with former IOC acting-president Dick Pound, a former Olympian, elected as a strong president. Below will be discussed three major doping aspects, regarding muscle, blood and the genome.

Muscle

Competitors seek to induce muscle hypertrophy by variously utilising growth hormone (hGH), anabolic steroids, ‘designer steroids’, or possibly in the future by inhibiting myostatin, the muscle’s normal limiter. The main reason for the popularity of hGH was that it has been hitherto undetectable. However, Peter Sonksen has headed a team which developed a test for use in Athens. Anabolic steroids have been in sport for several decades; the main problem with the detection of such hormone-based drugs has been that they are used mainly during strength-training mesocycles in a periodised training regimen, which usually occur months before competition. However, ‘out-of-competition’ testing, where available, has helped to cut down their use. Nevertheless, the athletes (or rather the illegal laboratories) have responded by synthesising ‘designer’ steroids, the design being to foil the test procedures. In June 2003 the USA Doping Agency was tipped off via an anonymous syringe, which they sent on to Don Catlin’s Olympic analytical laboratory at UCLA, where it was eventually identified as containing tetrahydrogestrinone (THG), related to the banned anabolic steroid gestrionone (Knight, 2003). However, the standard test for steroids has initially involved a gas chromatography scan, with fine tuning by mass spectrometry. Normally, appropriately prepared steroids show a sharp chromatograph peak – but in the case of THG there was only a couple of dozen small peaks, i.e. a negative result on the first screening, hence the analysis would not normally be taken further. Other designer doping agents no doubt exist. While not ‘designed’, Nandrolone is a steroid which has been newsworthy in the past few years, partly because it seems that some legitimate ergogenic ‘supplements’ (e.g. creatine) have been deliberately contaminated with nandrolone, to increase their efficacy, and hence sales. This may have led to doping tests on some competitors being positive, but at levels only marginally above the designated threshold.

Myostatin is a compound whose normal function is to limit muscle growth, by effectively down-regulating satellite cells. The Belgian Blue breed of beef cattle is genetically deficient in myostatin, and consequently looks like the bovine equivalent of hypertrophic bodybuilders. A similar (rare) condition has been reported in humans, and there is anecdotal belief that, over the years, some weightlifters have had the syndrome. However, were an artificial myostatin inhibitor to come onto the (black) market, muscle hypertrophy could possibly be taken to new limits. Roger Harris of Chichester notes that the current emphasis on gross muscle development of body-builders may already lead to their approaching the limits to which muscle may hypertrophy, before suffering the human equivalent of Green Muscle Disease of turkeys, a deep pectoral myopathy involving focal necrosis, which tends to occur in turkeys of above 80kg live-weight.

Blood

Erythropoeitin (EPO) is a juxta-glomerular anti-apoptopic agent that stimulates erythroid progenitor cells. It is upregulated in hypoxic conditions including altitude, resulting in enhanced erythropoiesis. The resulting rise in circulating haemoglobin increases the oxygen carrying capacity of the blood. Endurance athletes use recombinant EPO (rHuEpo) to increase their maximal oxygen uptake, as did the banned Festina cycling team mentioned above. Similarly, last month, UK cyclist David Miller was stripped of his World time-trial title, and banned for 2 years. Oddly, even athletes in the sprints and power events (e.g. USA sprinter Kelli White) have taken rHuEpo, suggesting another possible doping effect unconnected with erythropoiesis.

The detection of rHuEpo has proved difficult, and setting a haematocrit ceiling is very unsatisfactory, for example where altitude may have been an influence. However, due to their structural microheterogeneity, natural and recombinant EPO comprise several isoforms, some of which have charge differences, and can be differentiated by isoelectric focussing in urine analysis (Lasne & de Ceaurriz, 2000), although this is only effective up to 3 days after taking rHuEpo. Alternatively, my PhD student Brian Moore, among others, is researching the use of reticulocyte profiling and analysis as a possible means of somewhat longer-term detection.

However, artificial oxygen carriers (both haemoglobin based, e.g. Hemolink, and perflurorocarbons, e.g. Oxyfluor), are increasingly being developed and used, and the athletes are also tending to revert to the less detectable autologous ‘blood doping’ (the venesection and storage of one or two units of blood and their re-transfusion some 4 weeks later). The overall response of the dope-testers must be to increase out-of-competition testing and to institute haematological passports, in targeted sports.

The genome

Although not yet a reality as far as is known, ‘gene doping’ is defined by WADA (2004) as ‘the non-therapeutic use of genes, genetic elements and/or cells, that have the capacity to enhance athletic performance’. Montgomery et al (1998) were the first to provide clear evidence of a ‘fitness’ gene, namely the ACE-II insertion 287 base-pair allele giving lower angiotensin converter enzyme activity, with enhanced endurance performance (possibly through improved mitochondrial function). Now a considerable number of genes influencing physical fitness parameters are known.

Genes have already been introduced to human patients with, for example, immune deficiency syndromes, with some success. Also, Sweeney (2004) has used an adeno-associated virus (AAV, which infects muscle, harmlessly) as a vector for a synthetic gene coding for insulin-like growth factor 1 (IGLF-1), that triggers replication of muscle satellite cells, which stimulate muscle hypertrophy. His group injected AAV-IGLF-1 into the muscle of one leg in rats, then strength-trained the rats. After 8 weeks the experimental muscle showed nearly twice the strength gains of the control legs; even sedentary treated rats showed a 15% increase.

Experiments on mice genetically engineered to produce less effective myostatin (see above), have shown that diminishing this anti-growth factor induces both hypertrophy and, unusually, muscle hyperplasia, again possibly through up-regulating satellite cell behaviour. Another natural fitness gene is one that appears to positively influence the EPO receptor, as in Eero Maentyranta, who won two cross-country skiing events at the 1964 Winter Olympics and who, with members of his family, was found to have such a mutation. Elemans et al (2004) recently reported on a ‘superfast‘ muscle’ in the syrinx vocal organ of the ring dove; might the code from that be utilised for human sprinters?

The integration of genome datasets with physiological performance parameters is in its infancy, but will accelerate; and it is not only the encoded protein itself, but its rate of transcription, that is also important, so aspects of gene expression profiling may also come to be of use to sports competitors, possibly legitimately. Just as pharmacogenetics may usefully elicit differences in response to medicinal drugs in patients, so a form of athleticogenetics may help coaches to optimise training very specifically. All that would seem to lie some time in the future, although Theodore Friedman, member of the WADA committee believes that gene doping will occur ‘sooner than people think’, (in Beijing in 2008 perhaps?), and Peter Schjerling from the Copenhagen Muscle Research Centre, speaking at the 2001 London conference on genes and sport, indicated that such ‘gene doping’ could be near-impossible to detect. The induced cell signals or products are indistinguishable from natural equivalents, and may not enter the blood.

In conclusion, although the measured sports, especially, are tainted by doping, which in part is a result of sheer commercialism, there are overall, in a range of sports as wide as in the Summer and Winter Olympic Games, thousands of superb displays of skill and tenacity from utterly dedicated ‘clean’ competitors. Let us hope that most of them in the future will still be able to say, with Addison: ‘Tis not in mortals to command success, but we’ll do more, Sempronius, we’ll deserve it.’

Acknowledgement

It is a pleasure warmly to acknowledge help from my excellent research students Brian Moore and Isabel Woodman.

References

Elemans CPH, Spierts ILY & Muller UK (2004). Superfast muscles control Dove’s trill. Nature 431, 146.

Knight J (2003). No dope. Nature 426, 114-115.

Lasne F, de Ceaurriz J (2000). Recombinant erythropoietin in urine, Nature 405. 635.

Montgomery H E, Marshall R & Rayson M (1998) Human gene for physical performance. Nature 393, 221-222.

Sharp NCC (1999). Drugs wipe out a sporting chance. Nature 398, 675.

Sweeney H L (2004). Gene doping. Sci Am 291, 36-43