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

Doping Prevalence among U.S. Elite Athletes Subject to Drug Testing under the World Anti-Doping Code

BACKGROUND

Determining the prevalence of doping within an elite athlete population is challenging due to the extreme sensitivity of the topic; however, understanding true doping prevalence is important when designing anti-doping programs and measuring their effectiveness. The objective of this study was to estimate the prevalence of doping among Olympic, Paralympic, World, and National-level competitive athletes in the United States subject to the World Anti-Doping Code. All athletes who were subject to the U.S. Anti-Doping Agency's Protocol for Olympic and Paralympic Movement Testing, a World Anti-Doping Code ("Code")-compliant anti-doping program, were invited to complete a web-delivered survey. Using a direct questioning approach, the survey items asked athletes whether they had used each specific category of banned substance / method on the World Anti-Doping Agency's Prohibited List. Multiple strategies to encourage honest reporting (e.g., protecting anonymity by collecting minimal demographic information; using an outside organization to administer the survey) and to detect inconsistent responses were used.

RESULTS

Depending on the method of calculation, 6.5-9.2% of the 1,398 respondents reported using one or more prohibited substances or methods in the 12 months prior to survey administration. Specific doping prevalence rates for each individual substance / method categories ranged from 0.1% (for both diuretics / masking agents and stem cell / gene editing) to 4.2% for in-competition use of cannabinoids.

CONCLUSION

Determining the prevalence of doping within different athlete populations is critical so that sport governing bodies can evaluate their anti-doping efforts and better tailor their programming. By measuring doping prevalence of specific categories of substances and methods, rather than just the overall prevalence of doping, this study also highlights where sport governing bodies should focus their future educational and detection efforts.

Genetics and athletic performance: a systematic SWOT analysis of non-systematic reviews

Exercise genetics/genomics is a growing research discipline comprising several Strengths and Opportunities but also deals with Weaknesses and Threats. This "systematic SWOT overview of non-systematic reviews" (sSWOT) aimed to identify the Strengths, Weaknesses, Opportunities, and Threats linked to exercise genetics/genomics. A systematic search was conducted in the Medline and Embase databases for non-systematic reviews to provide a comprehensive overview of the current literature/research area. The extracted data was thematically analyzed, coded, and categorized into SWOT clusters. In the 45 included reviews five Strengths, nine Weaknesses, six Opportunities, and three Threats were identified. The cluster of Strengths included "advances in technology", "empirical evidence", "growing research discipline", the "establishment of consortia", and the "acceptance/accessibility of genetic testing". The Weaknesses were linked to a "low research quality", the "complexity of exercise-related traits", "low generalizability", "high costs", "genotype scores", "reporting bias", "invasive methods", "research progress", and "causality". The Opportunities comprised of "precision exercise", "omics", "multicenter studies", as well as "genetic testing" as "commercial"-, "screening"-, and "anti-doping" detection tool. The Threats were related to "ethical issues", "direct-to-consumer genetic testing companies", and "gene doping". This overview of the present state of the art research in sport genetics/genomics indicates a field with great potential, while also drawing attention to the necessity for additional advancement in methodological and ethical guidance to mitigate the recognized Weaknesses and Threats. The recognized Strengths and Opportunities substantiate the capability of genetics/genomics to make significant contributions to the performance and wellbeing of athletes.

CRISPR/deadCas9-based high-throughput gene doping analysis (HiGDA): A proof of concept for exogenous human erythropoietin gene doping detection

A genetic approach targeted toward improving athletic performance is called gene doping and is prohibited by the World Anti-Doping Agency. Currently, the clustered regularly interspaced short palindromic repeats-associated protein (Cas)-related assays have been utilized to detect genetic deficiencies or mutations. Among the Cas proteins, deadCas9 (dCas9), a nuclease-deficient mutant of Cas9, acts as a DNA binding protein with a target-specific single guide RNA. On the basis of the principles, we developed a dCas9-based high-throughput gene doping analysis for exogenous gene detection. The assay comprises two distinctive dCas9s, a magnetic bead immobilized capture dCas9 for exogenous gene isolation and a biotinylated dCas9 with streptavidin-polyHRP that enables rapid signal amplification. For efficient biotin labeling via maleimide-thiol chemistry, two cysteine residues of dCas9 were structurally validated, and the Cys574 residue was identified as an essential labeling site. As a result, we succeeded in detecting the target gene in a concentration as low as 12.3 fM (7.41 × 10⁵ copies) and up to 10 nM (6.07 × 10¹¹ copies) in a whole blood sample within 1 h with HiGDA. Assuming an exogenous gene transfer scenario, we added a direct blood amplification step to establish a rapid analytical procedure while detecting target genes with high sensitivity. Finally, we detected the exogenous human erythropoietin gene at concentrations as low as 2.5 copies within 90 min in 5 μL of the blood sample. Herein, we propose that HiGDA is a very fast, highly sensitive, and practical detection method for actual doping field in the future.

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.

The Prospective Study of Epigenetic Regulatory Profiles in Sport and Exercise Monitored Through Chromosome Conformation Signatures

The integration of genetic and environmental factors that regulate the gene expression patterns associated with exercise adaptation is mediated by epigenetic mechanisms. The organisation of the human genome within three-dimensional space, known as chromosome conformation, has recently been shown as a dynamic epigenetic regulator of gene expression, facilitating the interaction of distal genomic regions due to tight and regulated packaging of chromosomes in the cell nucleus. Technological advances in the study of chromosome conformation mean a new class of biomarker-the chromosome conformation signature (CCS)-can identify chromosomal interactions across several genomic loci as a collective marker of an epigenomic state. Investigative use of CCSs in biological and medical research shows promise in identifying the likelihood that a disease state is present or absent, as well as an ability to prospectively stratify individuals according to their likely response to medical intervention. The association of CCSs with gene expression patterns suggests that there are likely to be CCSs that respond, or regulate the response, to exercise and related stimuli. The present review provides a contextual background to CCS research and a theoretical framework discussing the potential uses of this novel epigenomic biomarker within sport and exercise science and medicine.

The Role of AMPK/mTOR Modulators in the Therapy of Acute Myeloid Leukemia

Differentiation therapy of acute promyelocytic leukemia with all-trans retinoic acid represents the most successful pharmacological therapy of acute myeloid leukemia (AML). Numerous studies demonstrate that drugs that inhibit mechanistic target of rapamycin (mTOR) and activate AMP-kinase (AMPK) have beneficial effects in promoting differentiation and blocking proliferation of AML. Most of these drugs are already in use for other purposes; rapalogs as immunosuppressants, biguanides as oral antidiabetics, and 5-amino-4-imidazolecarboxamide ribonucleoside (AICAr, acadesine) as an exercise mimetic. Although most of these pharmacological modulators have been widely used for decades, their mechanism of action is only partially understood. In this review, we summarize the role of AMPK and mTOR in hematological malignancies and discuss the possible role of pharmacological modulators in proliferation and differentiation of leukemia cells.

'Blood doping' from Armstrong to prehabilitation: manipulation of blood to improve performance in athletes and physiological reserve in patients

Haemoglobin is the blood’s oxygen carrying pigment and is encapsulated in red blood corpuscles. The concentration of haemoglobin in blood is dependent on both its total mass in the circulation (tHb-mass) and the total plasma volume in which it is suspended. Aerobic capacity is defined as the maximum amount of oxygen that can be consumed by the body per unit time and is one measure of physical fitness. Observations in athletes who have undergone blood doping or manipulation have revealed a closer relationship between physical fitness (aerobic capacity) and total haemoglobin mass (tHb-mass) than with haemoglobin concentration ([Hb]). Anaemia is defined by the World Health Organisation (WHO) as a haemoglobin concentration of <130 g/L for men and <120 g/L for women. Perioperative anaemia is a common problem and is associated with increased mortality and morbidity following surgery. Aerobic capacity is also associated with outcome following major surgery, with less fit patients having a higher incidence of mortality and morbidity after surgery. Taken together, these observations suggest that targeted preoperative elevation of tHb-mass may raise aerobic capacity both directly and indirectly (by augmenting preoperative exercise initiatives- ‘prehabilitation’) and thus improve postoperative outcome. This notion in turn raises a number of questions. Which measure ([Hb] or tHb-mass) has the most value for the description of oxygen carrying capacity? Which measure has the most utility for targeting therapies to manipulate haemoglobin levels? Do the newer agents being used for blood manipulation (to increase tHb-mass) in elite sport have utility in the clinical environment? This review explores the literature relating to blood manipulation in elite sport as well as the relationship between perioperative anaemia, physical fitness and outcome following surgery, and suggests some avenues for exploring this area further.

Myostatin--the holy grail for muscle, bone, and fat?

Myostatin, a member of the transforming growth factor beta (TGF-β) superfamily, was first described in 1997. Since then, myostatin has gained growing attention because of the discovery that myostatin inhibition leads to muscle mass accrual. Myostatin not only plays a key role in muscle homeostasis, but also affects fat and bone. This review will focus on the impact of myostatin and its inhibition on muscle mass/function, adipose tissue and bone density/geometry in humans. Although existing data are sparse, myostatin inhibition leads to increased lean mass and 1 study found a decrease in fat mass and increase in bone formation. In addition, myostatin levels are increased in sarcopenia, cachexia and bed rest whereas they are increased after resistance training, suggesting physiological regulatory of myostatin. Increased myostatin levels have also been found in obesity and levels decrease after weight loss from caloric restriction. Knowledge on the relationship of myostatin with bone is largely based on animal data where elevated myostatin levels lead to decreased BMD and myostatin inhibition improved BMD. In summary, myostatin appears to be a key factor in the integrated physiology of muscle, fat, and bone. It is unclear whether myostatin directly affects fat and bone, or indirectly via muscle. Whether via direct or indirect effects, myostatin inhibition appears to increase muscle and bone mass and decrease fat tissue-a combination that truly appears to be a holy grail. However, at this time, human data for both efficacy and safety are extremely limited. Moreover, whether increased muscle mass also leads to improved function remains to be determined. Ultimately potential beneficial effects of myostatin inhibition will need to be determined based on hard outcomes such as falls and fractures.