Measurement of free IGF-I saliva levels: Perspectives in the detection of GH/IGF axis in athletes

Influence of High-Intensity Interval Training on IGF-1 Response, Brain Executive Function, Physical Fitness and Quality of Life in Sedentary Young University Women-Protocol for a Randomized Controlled Trial

Sedentary lifestyles have become a social problem, mainly among women. A sedentary lifestyle has been associated with poorer health in this population, negatively affecting physical and mental health. Physical exercise, in particular high-intensity interval training (HIIT), has been shown to be a neuroprotective tool. The present study provides a protocol design for a parallel-group Randomized Controlled Trial (RCT), whose aim will be to compare the effect of two physical interventions, HIIT and physical activity (increasing daily steps), on Insulin Growth Factor-1 (saliva IGF-1 concentrations), executive functions, quality of life, body composition, physical fitness, and physical activity in young sedentary women. At least 77 women will be recruited and randomly assigned to either a HIIT group (12-week exercise HIIT intervention, 3 sessions/week), the HIIT + PA group (12-week exercise HIIT intervention, 3 sessions/week, plus 10,000 steps/day), or a control group (usual care). The primary outcome measure will the chronic change in IGF-1 concentration levels measured in saliva. Secondary outcome measures will be: (i) executive functions; (ii) body composition; (iii) physical fitness; (iv) physical activity; and (v) quality of life. All outcomes will be assessed at the beginning of the study, after the intervention, and after three months of follow-up. After this intervention, we will be able to determine whether HIIT together with increased physical activity could be more effective than HIIT alone in IGF-1 stimulation. Furthermore, by comparing both intervention groups, we will be able to determine the differential effects on numerous health-related variables. Consequently, the conclusions of this study could help better understand the effects of a training program on IGF-1 concentration levels and executive functions. In addition, various strategies could be proposed through physical exercise to improve cognition in this age group, as well as to improve the health status of this sedentary population.

The Effects of Physical Exercise on Saliva Composition: A Comprehensive Review

Saliva consists of organic and inorganic constituents. During exercise, analysis of the saliva can provide valuable information regarding training stress, adaptation and exercise performance. The objective of the present article was to review the effect of physical exercise on saliva composition. The shift in the composition of the saliva, during and after a workout, reflects the benefits of exercise, its potential risks and the capability of the saliva to serve as a health indicator. The type and the frequency of training, the physical condition and the athletes’ general health influence the hormones, immunoglobulins and saliva enzymes. The correlation between saliva and physical exercise has to be further investigated and the available knowledge to be applied for the benefit of the athletes during sports activities.

The Impact of Professional Sports Activity on GH-IGF-I Axis in Relation to Testosterone Level

The study was designed to investigate whether sports-induced elevation of testosterone level impacts on the growth hormone/insulin-like growth factor-I (GH-IGF-I) axis and body composition, especially skeletal muscle mass. The study included 12 male wrestlers aged 21.1 ± 1.7 years and 10 male nonathletes aged 21.1 ± 1.2 years. Anthropometric and biochemical measurements in the group of nonathlete men were carried out once, while for wrestlers they were carried out twice, that is, on the 1st and 14th days of the training camp.

The levels of resting free testosterone (fT), cortisol (C), and human growth hormone (hGH) were significantly higher in the athletes than in nonathletes. A 2-week sports training induced a significant reduction in fT, IGF-I, and IGF binding protein-3 (IGFBP-3) levels and a rise in C level. Increased C level and reduced fT level in the athletes’ blood caused a rise in C/fT from the level of 39.95 ± 4.97 nmol/L to 59.73 ± 10.09 nmol/L (p < .05). A negative correlation was demonstrated between C/fT ratio and IGF-I level (r = −0.474, p < .05), which may indicate an inhibitory impact of high C level and low fT concentration on IGF-I release in response to sports training.

Sports activity induces significant changes in the C/fT ratio that can impact on the secretion of GH and IGF-I from the liver and finally on the fat-free body mass. The quantification of GH-IGF-I axis in relation to testosterone level could be a useful diagnostic tool in biochemical assessment of the regenerative ability of skeletal muscle or provide evidence of the early stages of muscle functional overload.

Sleep extension increases IGF-I concentrations before and during sleep deprivation in healthy young men

Sleep deprivation is known to suppress circulating trophic factors such as insulin-like growth factor (IGF)-I and brain-derived neurotrophic factor (BDNF). This experiment examined the effect of an intervention involving 6 nights of extended sleep before total sleep deprivation on this catabolic profile. In a randomized crossover design, 14 young men (age range: 26–37 years) were either in an extended (EXT; time in bed: 2100–0700 h) or habitual (HAB: 2230–0700 h) sleep condition, followed by 3 days in the laboratory with blood sampling at baseline (B), after 24 h of sleep deprivation (24h-SD), and after 1 night of recovery sleep (R). In the EXT condition compared with the HAB condition, free IGF-I levels were significantly higher at B, 24h-SD, and R (P < 0.001), and those of total IGF-I at B and 24h-SD (P < 0.05). EXT did not influence growth hormone, IGF binding protein 3, BDNF, insulin, and glucose levels. The only effect of 24 h of sleep deprivation was for insulin levels, which were significantly higher after R compared with B. In a healthy adult, additional sleep over 1 week increased blood concentrations of the anabolic factor IGF-I before and during 24 h of sleep deprivation and after the subsequent recovery night without effects on BDNF. With further research, these findings may prove to be important in guiding effective lifestyle modifications to limit physical or cognitive deficits associated with IGF-I decrease with age.

The potential role of oral fluid in antidoping testing

BACKGROUND

Currently, urine and blood are the only matrices authorized for antidoping testing by the World Anti-Doping Agency (WADA). Although the usefulness of urine and blood is proven, issues remain for monitoring some drug classes and for drugs prohibited only in competition. The alternative matrix oral fluid (OF) may offer solutions to some of these issues. OF collection is easy, noninvasive, and sex neutral and is directly observed, limiting potential adulteration, a major problem for urine testing. OF is used to monitor drug intake in workplace, clinical toxicology, criminal justice, and driving under the influence of drugs programs and potentially could complement urine and blood for antidoping testing in sports.

CONTENT

This review outlines the present state of knowledge and the advantages and limitations of OF testing for each of the WADA drug classes and the research needed to advance OF testing as a viable alternative for antidoping testing.

SUMMARY

Doping agents are either prohibited at all times or prohibited in competition only. Few OF data from controlled drug administration studies are available for substances banned at all times, whereas for some agents prohibited only in competition, sufficient data may be available to suggest appropriate analytes and cutoffs (analytical threshold concentrations) to identify recent drug use. Additional research is needed to characterize the disposition of many banned substances into OF; OF collection methods and doping agent stability in OF also require investigation to allow the accurate interpretation of OF tests for antidoping monitoring.

Potential and limitations of alternative specimens in doping control

Alternative specimens (e.g., hair and saliva) are well established in forensic toxicology and provide significant benefits as noninvasive, inexpensive alternatives to blood with access to improved long-term retrospection. Based on these experiences, the question of potential applications and limitations of alternative specimens in doping control arose. Compounds prohibited at all times (e.g., clenbuterol, β2 agonists, estrogen-receptor modulators) may be successfully tested and clearly interpreted in alternative specimens. In contrast, prohibition of certain compounds in sport are limited to time ranges (e.g., stimulants are only prohibited in-competition), dosages or administration routes (e.g., systemic uptake of glucocorticosteroids). This cannot be properly differentiated by semiquantitative tests (e.g., hair analyses), but may be distinguished in saliva. Similarly, proof of external administration of endogenous steroids (e.g., testosterone) only seems to be achievable by quantitative analysis of saliva. Moreover, the retrospective monitoring of the relevance of social drugs or upcoming (unapproved) substances represents promising applications of hair tests in doping control.

Growth hormone doping in sports: a critical review of use and detection strategies

GH is believed to be widely employed in sports as a performance-enhancing substance. Its use in athletic competition is banned by the World Anti-Doping Agency, and athletes are required to submit to testing for GH exposure. Detection of GH doping is challenging for several reasons including identity/similarity of exogenous to endogenous GH, short half-life, complex and fluctuating secretory dynamics of GH, and a very low urinary excretion rate. The detection test currently in use (GH isoform test) exploits the difference between recombinant GH (pure 22K-GH) and the heterogeneous nature of endogenous GH (several isoforms). Its main limitation is the short window of opportunity for detection (~12-24 h after the last GH dose). A second test to be implemented soon (the biomarker test) is based on stimulation of IGF-I and collagen III synthesis by GH. It has a longer window of opportunity (1-2 wk) but is less specific and presents a variety of technical challenges. GH doping in a larger sense also includes doping with GH secretagogues and IGF-I and its analogs. The scientific evidence for the ergogenicity of GH is weak, a fact that is not widely appreciated in athletic circles or by the general public. Also insufficiently appreciated is the risk of serious health consequences associated with high-dose, prolonged GH use. This review discusses the GH biology relevant to GH doping; the virtues and limitations of detection tests in blood, urine, and saliva; secretagogue efficacy; IGF-I doping; and information about the effectiveness of GH as a performance-enhancing agent.

Salivary free insulin-like growth factor-i levels: effects of an acute physical exercise in athletes

BACKGROUND/AIMS

The offer of human saliva IGF-I (sIGF-I) measurement in athletes investigation is a new proposal. The aim was to investigate the physical exercise effect on sIGF-I and explore plasma free IGF-I relation.

MATERIALS AND METHODS

Saliva and blood were collected from well-trained athletes, investigated immediately before and at the end of a physical exercise test.

RESULTS

sIGF-I was significantly increased at the end of the physical exercise. The plasma free IGF-I concentrations did not demonstrate any difference. The saliva total protein level (sTP) was also significantly increased. A positive correlation between sTP and sIGF-I, was observed, both before and after physical exercise, and between salivary and plasma free IGF-I only after physical exercise. The salivary free IGF-I level significantly increased after physical exercise, moreover a correlation with the plasma levels exists in post-exercise condition.

CONCLUSION

The physical exercise affects sIGF-I as well as the sTP. The correlation between plasma and salivary free IGF-I levels only in post-exercise condition suggests further studies to investigate the effects of different type and duration of physical exercise. The comparison with other salivary biochemical parameter investigation would also further increase comprehension on the role of salivary IGF-I.