Exercise and the Growth Hormone-Insulin-Like Growth Factor Axis

Circulating free insulin-like growth factor-I and prostate cancer: a case-control study nested in the European prospective investigation into cancer and nutrition

BACKGROUND

Circulating total insulin-like growth factor-I (IGF-I) is an established risk factor for prostate cancer. However, only a small proportion of circulating IGF-I is free or readily dissociable from IGF-binding proteins (its bioavailable form), and few studies have investigated the association of circulating free IGF-I with prostate cancer risk.

METHODS

We analyzed data from 767 prostate cancer cases and 767 matched controls nested within the European Prospective Investigation into Cancer and Nutrition cohort, with an average of 14-years (interquartile range = 2.9) follow-up. Matching variables were study center, length of follow-up, age, and time of day and fasting duration at blood collection. Circulating free IGF-I concentration was measured in serum samples collected at recruitment visit (mean age 55 years old; standard deviation = 7.1) using an enzyme-linked immunosorbent assay (ELISA). Conditional logistic regressions were performed to examine the associations of free IGF-I with risk of prostate cancer overall and subdivided by time to diagnosis (≤ 14 and > 14 years), and tumor characteristics.

RESULTS

Circulating free IGF-I concentrations (in fourths and as a continuous variable) were not associated with prostate cancer risk overall (odds ratio [OR] = 1.00 per 0.1 nmol/L increment, 95% CI: 0.99, 1.02) or by time to diagnosis, or with prostate cancer subtypes, including tumor stage and histological grade.

CONCLUSIONS

Estimated circulating free IGF-I was not associated with prostate cancer risk. Further research may consider other assay methods that estimate bioavailable IGF-I to provide more insight into the well-substantiated association between circulating total IGF-I and subsequent prostate cancer risk.

Sex-based differences in growth-related IGF1 signaling in response to PAPP-A2 deficiency: comparative effects of rhGH, rhIGF1 and rhPAPP-A2 treatments

BACKGROUND

Children with pregnancy-associated plasma protein-A2 (PAPP-A2) mutations resulting in low levels of bioactive insulin-like growth factor-1 (IGF1) and progressive postnatal growth retardation have improved growth velocity and height following recombinant human (rh)IGF1 treatment. The present study aimed to evaluate whether Pappa2 deficiency and pharmacological manipulation of GH/IGF1 system are associated with sex-specific differences in growth-related signaling pathways.

METHODS

Plasma, hypothalamus, pituitary gland and liver of Pappa2ko/ko mice of both sexes, showing reduced skeletal growth, and liver of these mice treated with rhGH, rhIGF1 and rhPAPP-A2 from postnatal day (PND) 5 to PND35 were analyzed.

RESULTS

Reduced body and femur length of Pappa2ko/ko mice was associated with increases in: (1) components of IGF1 ternary complexes (IGF1, IGFBP5/Igfbp5, Igfbp3, Igfals) in plasma, hypothalamus and/or liver; and (2) key signaling regulators (phosphorylated PI3K, AKT, mTOR, GSK3β, ERK1/2 and AMPKα) in hypothalamus, pituitary gland and/or liver, with Pappa2ko/ko females having a more prominent effect. Compared to rhGH and rhIGF1, rhPAPP-A2 specifically induced: (1) increased body and femur length, and reduced plasma total IGF1 and IGFBP5 concentrations in Pappa2ko/ko females; and (2) increased Igf1 and Igf1r levels and decreased Ghr, Igfbp3 and Igfals levels in the liver of Pappa2ko/ko females. These changes were accompanied by lower phospho-STAT5, phospho-AKT and phospho-ERK2 levels and higher phospho-AMPK levels in the liver of Pappa2ko/ko females.

CONCLUSIONS

Sex-specific differences in IGF1 system and signaling pathways are associated with Pappa2 deficiency, pointing to rhPAPP-A2 as a promising drug to alleviate postnatal growth retardation underlying low IGF1 bioavailability in a female-specific manner.

GH and IGF-1 in skin interstitial fluid and blood are associated with heat loss responses in exercising young adults

PURPOSE

Sweat glands and cutaneous vessels possess growth hormone (GH) and insulin-like growth factor 1 (IGF-1) receptors. Here, we assessed if exercise increases GH and IGF-1 in skin interstitial fluid, and whether baseline and exercise-induced increases in GH and IGF-1 concentrations in skin interstitial fluid/blood are associated with heat loss responses of sweating and cutaneous vasodilation.

METHODS

Sixteen young adults (7 women) performed a 50-min moderate-intensity exercise bout (50% VO2peak) during which skin dialysate and blood samples were collected. In a sub-study (n = 7, 4 women), we administered varying concentrations of GH (0.025-4000 ng/mL) and IGF-1 (0.000256-100 µg/mL) into skin interstitial fluid via intradermal microdialysis. Sweat rate (ventilated capsule) and cutaneous vascular conductance (CVC) were measured continuously for both studies.

RESULTS

Exercise increased sweating and CVC (both P < 0.001), paralleled by increases of serum GH and skin dialysate GH and IGF-1 (all P ≤ 0.041) without changes in serum IGF-1. Sweating was positively correlated with baseline dialysate and serum GH levels, as well as exercise-induced increases in serum GH and IGF-1 (all P ≤ 0.044). Increases in CVC were not correlated with any GH and IGF-1 variables. Exogenous administration of GH and IGF-1 did not modulate resting sweat rate and CVC.

CONCLUSION

(1) Exercise increases GH and IGF-1 levels in the skin interstitial fluid, (2) exercise-induced sweating is associated with baseline GH in skin interstitial fluid and blood, as well as exercise-induced increases in blood GH and IGF-1, and (3) cutaneous vasodilation during exercise is not associated with GH and IGF-1 in skin interstitial fluid and blood.

Muscle hypertrophy training does not suppress the GH/IGF axis in young adult males

PURPOSE

This study aimed to analyze the expression of the IGF type-1 receptor gene (IGF-1r) and IGF-I, GH, testosterone, and IGFBP-3 concentrations in young people subjected to 10 weeks of muscle hypertrophy training.

METHODS

IGF-1r expression, serum concentrations of IGF-I, IGFBP-3, GH, and total testosterone, as well as body composition, fat percentage, and body mass index, were determined for 22 healthy young males at three moments of resistance training (first, fifth, and tenth week of training).

RESULTS

Throughout the 10 weeks of training, a reduction was observed in the relative expression of the IGF-1r gene (2-ΔΔCT) and an increase in IGF-I and GH concentrations. A reduction in total testosterone concentrations was detected during the recovery period in the fifth week. The IGFBP-3 concentrations did not change throughout the training.

CONCLUSIONS

The resistance training protocol prescribed for muscle hypertrophy did not suppress the GH-IGF-I axis, but it did cause alterations in IGF-1r gene expression and in IGF-I kinetics compatible with increased IGF bioactivity.

The role of exercise in obesity-related cancers: Current evidence and biological mechanisms

Cancer ranks among the five leading causes of death in almost all countries and has important repercussions for individual and public health, the healthcare system, and society in general. Obesity increases the incidence of many types of cancer, but growing evidence suggests that physical activity may decrease risk for developing a variety of obesity-related cancer types, and, in some cases, may improve cancer prognosis and mortality rates. This review summarizes recent evidence on the effect of physical activity on obesity-related cancer prevention and survival. For some cancers, including breast, colorectal, and endometrial cancer, there is strong evidence for a preventative effect of exercise, but for many others, including gallbladder and kidney cancer, and multiple myeloma, evidence is inconsistent or largely lacking. Though many potential mechanisms have been proposed to explain the onco-protective effect of exercise, including improved insulin sensitivity, alterations in sex hormone availability, improved immune function and inflammation, myokine secretion, and modulation of intracellular signaling at the level of AMP kinase, the exact mechanism(s) of action within each cancer subtype remains poorly defined. Overall, a deeper understanding of how exercise can help against cancer and of the exercise parameters that can be altered to optimize exercise prescription is necessary and should be the subject of future investigation.

Effects of Taekwondo Training on Growth Factors in Normal Korean Children and Adolescents: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

The growth of children and adolescents is both an important health indicator and a major public health issue. Many recent studies have investigated the effects of taekwondo on growth factors, but no consensus has yet been reached. This meta-analysis aimed to determine the effects of taekwondo on the growth factors in children and adolescents (aged 8 to 16 years). Randomized controlled trials from PubMed, Web of Science, Cochrane Library, the Research Information Sharing Service, the Korea Citation Index, and the Korean-studies Information Service System were analyzed. The effect sizes (standardized mean differences, SMD) were calculated, the risk of bias and publication bias were assessed, and the effect size and subgroup analyses were pooled. We found that the taekwondo group had significantly higher levels of growth hormones (SMD 1.78, 95% confidence interval [CI] 0.98-2.58, and p < 0.001) and insulin-like growth factors (SMD 1.76, 95% CI 0.60-2.92, and p < 0.001) than the control group. For height, a medium effect size was observed (SMD 0.62, 95% CI -0.56-1.80, and p = 0.300), but the between-group difference was not significant. Thus, taekwondo had significant positive effects on the secretion of growth hormones and insulin-like growth factors in Korean children and adolescents. A longitudinal follow-up is necessary to determine the effect on height. This suggests that taekwondo can be recommended as an appropriate physical exercise for maintaining normal growth in children and adolescents.

Biochemical Markers of Musculoskeletal Health and Aging to be Assessed in Clinical Trials of Drugs Aiming at the Treatment of Sarcopenia: Consensus Paper from an Expert Group Meeting Organized by the European Society for Clinical and Economic Aspects of Osteoporosis, Osteoarthritis and Musculoskeletal Diseases (ESCEO) and the Centre Académique de Recherche et d'Expérimentation en Santé (CARES SPRL), Under the Auspices of the World Health Organization Collaborating Center for the Epidemiology of Musculoskeletal Conditions and Aging

In clinical trials, biochemical markers provide useful information on the drug's mode of action, therapeutic response and side effect monitoring and can act as surrogate endpoints. In pharmacological intervention development for sarcopenia management, there is an urgent need to identify biomarkers to measure in clinical trials and that could be used in the future in clinical practice. The objective of the current consensus paper is to provide a clear list of biochemical markers of musculoskeletal health and aging that can be recommended to be measured in Phase II and Phase III clinical trials evaluating new chemical entities for sarcopenia treatment. A working group of the European Society for Clinical and Economic Aspects of Osteoporosis, Osteoarthritis and Musculoskeletal Diseases (ESCEO) proposed classifying biochemical markers into 2 series: biochemical markers evaluating musculoskeletal status and biochemical markers evaluating causal factors. For series 1, the group agreed on 4 biochemical markers that should be assessed in Phase II or Phase III trials (i.e., Myostatin-Follistatin, Brain Derived Neurotrophic Factor, N-terminal Type III Procollagen and Serum Creatinine to Serum Cystatin C Ratio - or the Sarcopenia Index). For series 2, the group agreed on 6 biochemical markers that should be assessed in Phase II trials (i.e., the hormones insulin-like growth factor-1 (IGF-I), dehydroepiandrosterone sulphate, and cortisol, and the inflammatory markers C-reactive protein (CRP), interleukin-6 and tumor necrosis factor-α), and 2 in Phase III trials (i.e., IGF-I and CRP). The group also proposed optional biochemical markers that may provide insights into the mode of action of pharmacological therapies. Further research and development of new methods for biochemical marker assays may lead to the evolution of these recommendations.

The effect of Tribulus terrestris supplementation on inflammation, oxidative stress, and performance of recreational runners: study protocol for a randomized placebo-controlled trial

Background

High intensity and endurance exercises lead to exercise-induced oxidative stress (EIOS), exercise-induced muscle damage (EIMD), and inflammation, which are the influencing factors on muscle soreness, localized swelling, and sports performance decrease. Therefore, the purpose of this study is to determine the effectiveness of Tribulus terrestris (TT) as an herbal supplement with antioxidant and anti-inflammatory properties on the nutritional, oxidative, inflammatory, and anti-inflammatory status, as well as the sports performance of recreational runners.

Methods/design

This study is a double-blind, randomized, placebo-controlled trial, which will be conducted among recreational runners of Tabriz stadiums, Iran. Thirty-four recreational runners will be selected, and participants will be assigned randomly to two groups: to receive 500 mg TT supplement or placebo capsules twice daily for 2 weeks. Both groups will do high-intensity interval training (HIIT) workouts during the study. Baseline and post-intervention body composition, muscle pain, and aerobic and anaerobic performance will be assessed. In addition, assessment of malondialdehyde (MDA), total antioxidant capacity (TAC), total oxidant status (TOS), superoxide dismutase (SOD), glutathione peroxidase (GPx), uric acid (UA), 8-iso-prostaglandin F2α (8-iso-PGF2α), protein carbonyl (PC), catalase (CAT), glutathione (GSH), nitric oxide (NO), high-sensitivity C-reactive protein (hs-CRP), interleukin-6 (IL-6), interleukin-10 (IL-10), tumor necrosis factor-alpha (TNF-α), creatine kinase (CK), myoglobin (MYO), lactate dehydrogenase (LDH), insulin-like growth factor-1 (IGF-1) irisin, cortisol, and brain-derived neurotrophic factor (BDNF) will be done during three blood samplings. Changes in oxidative stress, anti/inflammatory biomarkers, and sports performance will be assessed as primary outcomes.

Discussion

This study will be the first to assess the potential effects of TT on recreational runners. Our results will contribute to the growing body of knowledge regarding TT supplementation on the nutritional, oxidative, inflammatory, and anti-inflammatory status and sports performance in recreational runners.

Trial registration

Iranian Registry of Clinical Trials (www.irct.ir) (ID: IRCT20150205020965N8). Registration date: 13 February 2021.

Effects of Tribulus terrestris L. on Sport and Health Biomarkers in Physically Active Adult Males: A Systematic Review

Tribulus terrestris L. (TT) is a plant used in traditional Chinese medicine, Ayurvedic medicine, and sports nutrition to improve health and performance. However, no conclusive evidence exists about the potential beneficial effects of TT on sport and health biomarkers in physically active adults. Based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, and the modified McMaster Critical Review Form for methodological quality assessment, we systematically reviewed studies indexed in Web of Science, Scopus, and PubMed, to assess the effects of TT on immunological, hematological, biochemical, renal, lipidic, hormonal behavior, and anti-inflammatory response in physically active adult males. Among 340 records identified in the search, a total of 7 studies met the inclusion and exclusion criteria. Overall, participants supplemented with TT displayed significant improvements in lipid profile. Inflammatory and hematological biomarkers showed moderate beneficial effects with no significant changes on renal biomarkers. No positive effects were observed on the immune system response. Additionally, no TT-induced toxicity was reported. In conclusion, there was no clear evidence of the beneficial effects of TT supplementation on muscle damage markers and hormonal behavior. More studies are needed to confirm the benefits of TT due to the limited number of studies available in the current literature.

The effect of date seed (Phoenix dactylifera) supplementation on inflammation, oxidative stress biomarkers, and performance in active people: A blinded randomized controlled trial protocol

Introduction

High-intensity interval training (HIIT) is an efficient training method to improve vascular function, maximal oxygen consumption, and muscle mitochondrial capacity while maximizing muscular damage. Recently, functional foods have been considered a practical approach to avoiding HIIT damage and improving sports performance. Thus, the present study will evaluate the effectiveness of date seed powder as a functional food on the nutritional, oxidative stress, anti/inflammatory status, mental health, and performance of active people.

Methods

This study is a double-blind, randomized, placebo-controlled trial, which will be conducted among recreational runners at Tabriz stadiums, Iran. Thirty-six recreational runners will be randomly selected into two groups to consume 26 g/d date seed powder or placebo for 14 days. Both groups will do HIIT workouts. Body composition, food intake, total antioxidant capacity (TAC), oxidative stress index (OSI), total oxidant status (TOS), superoxide dismutase (SOD), glutathione peroxidase (GPx), malondialdehyde (MDA), 8-iso-prostaglandin F2α (8-iso-PGF2α), uric acid, protein carbonyl (PC), catalase (CAT), glutathione (GSH), nitric oxide (NO), high-sensitivity C-reactive protein (hs-CRP), tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), interleukin-10 (IL-10), IL-6/IL-10, creatine kinase (CK), lactate dehydrogenase (LDH), myoglobin (MYO), brain-derived neurotrophic factor (BDNF), insulin-like growth factor-1 (IGF-1), irisin, cortisol, muscle pain, aerobic and anaerobic performance will be evaluated at the beginning, end of the intervention and 24 h later.

Ethics and dissemination

This study was approved by the Medical Ethics Committee of TBZMED (No.IR.TBZMED.REC.1399.1011). This research's findings will be published in a peer-reviewed journal and presented at international conferences.

Trial registration

Iranian Registry of Clinical Trials website (www.IRCT.ir/, IRCT20150205020965N9).

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Date seed powder may have the potential to improve exercise performance in healthy and active subjects performing HIIT bouts.

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The date seed is known as an excellent functional food due to its being high in polyphenols, and total dietary fiber.

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The consumption of date seed powder would improve oxidative stress, inflammation, mental health and performance.

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The results of this trial can be used to provide evidence-based recommendations for recreational runners, and nutritionists.

Cardio-Hypothalamic-Pituitary Coupling during Rest and in Response to Exercise

The objective of this study was to examine cardio hypothalamic-pituitary coupling and to better understand how the temporal relations between these systems are altered during rest and exercise conditions. An intensive within subjects study design was used. Seven adult males completed two visits, each consisting of either a 24 h period of complete rest or a 24 h period containing a high-intensity exercise bout. An intravenous catheter was used to collect serum samples every 10 min throughout the 24 h period (i.e., 145 samples/person/condition) to assess growth hormone (GH) dynamics throughout the 24 h period. Cardiac dynamics were also collected throughout the 24 h period and epoched into 3 min windows every 10 min, providing serial short-time measurements of heart rate variability (HRV) concurrent to the GH sampling. The standard deviation of the normal RR interval (SDNN), the root mean square of successive differences (rMSSD), and sample entropy (SampEn) was calculated for each epoch and used to create new profiles. The dynamics of these profiles were individually quantified using SampEn and recurrence quantification analysis (RQA). To address our central question, the coupling between these profiles with GH was assessed using cross-SampEn and cross-RQA (cRQA). A comparison between the epoched HRV profiles indicated a main effect between profiles for sample entropy (p < 0.001) and several measures from RQA. An interaction between profile and condition was observed for cross-SampEn (p = 0.04) and several measures from cRQA. These findings highlight the potential application of epoched HRV to assess changes in cardiac dynamics, with specific applications to assessing cardio hypothalamic-pituitary coupling.

Intermittent Exercise at Lactate Threshold Induces Lower Acute Stress than Its Continuous Counterpart in Middle-to-Older Aged Men

This study aimed to compare the degree of exhaustion and trophic effects between continuous exercise (CE) and intermittent exercise (IE) at lactate threshold (LT) intensity. Seven healthy men (age: 43-69 years) performed the following three experimental tests in a randomized crossover order: (1) control; (2) CE, performed as a 20-min of cycling at LT intensity; and (3) IE, performed as 20 sets of a one-min bout of cycling at LT intensity with a 30-s rest between every two sets. Heart rate (HR), blood lactate concentration (LA), rating of perceived exertion (RPE), catecholamines, cortisol, growth hormone, insulin-like growth factor (IGF)-1, and brain-derived neurotrophic factor (BDNF) were measured. The sampling timing in each test was as follows: 10 min before the onset of exercise, at the 25%, 50%, and 100% time points of exercise, and at 10 min after exercise. IE was found to be accompanied by a lower degree of exhaustion than CE in measures of HR, LA, RPE, catecholamines, and cortisol. In terms of trophic effects, both of IGF-1 and BDNF increased in CE, while a marginal increase of BDNF was observed in IE. The results indicated that IE induces lower stress than CE, but may not be effective for inducing trophic effects.

Muscle-brain communication in pain: The key role of myokines

Pain is the most common reason for a physician visit, which accounts for a considerable proportion of the global burden of disease and greatly affects patients' quality of life. Therefore, there is an urgent need to identify new therapeutic targets involved in pain. Exercise-induced hypoalgesia (EIH) is a well known phenomenon observed worldwide. However, the available evidence demonstrates that the mechanisms of EIH remain unclear. One of the most accepted hypotheses has been the activation of several endogenous systems in the brain. Recently, the concept that the muscle acts as a secretory organ has attracted increasing attention. Proteins secreted by the muscle are called myokines, playing a critical role in communicating with other organs, such as the brain. This review will focus on several myokines and discuss their roles in EIH.

Central Suppression of the GH/IGF Axis and Abrogation of Exercise-Related mTORC1/2 Activation in the Muscle of Phenotype-Selected Male Marathon Mice (DUhTP)

The somatotropic axis is required for a number of biological processes, including growth, metabolism, and aging. Due to its central effects on growth and metabolism and with respect to its positive effects on muscle mass, regulation of the GH/IGF-system during endurance exercise is of particular interest. In order to study the control of gene expression and adaptation related to physical performance, we used a non-inbred mouse model, phenotype-selected for high running performance (DUhTP). Gene expression of the GH/IGF-system and related signaling cascades were studied in the pituitary gland and muscle of sedentary males of marathon and unselected control mice. In addition, the effects of three weeks of endurance exercise were assessed in both genetic groups. In pituitary glands from DUhTP mice, reduced expression of Pou1f1 (p = 0.002) was accompanied by non-significant reductions of Gh mRNA (p = 0.066). In addition, mRNA expression of Ghsr and Sstr2 were significantly reduced in the pituitary glands from DUhTP mice (p ≤ 0.05). Central downregulation of Pou1f1 expression was accompanied by reduced serum concentrations of IGF1 and coordinated downregulation of multiple GH/IGF-signaling compounds in muscle (e.g., Ghr, Igf1, Igf1r, Igf2r, Irs1, Irs2, Akt3, Gskb, Pik3ca/b/a2, Pten, Rictor, Rptor, Tsc1, Mtor; p ≤ 0.05). In response to exercise, the expression of Igfbp3, Igfbp 4, and Igfbp 6 and Stc2 mRNA was increased in the muscle of DUhTP mice (p ≤ 0.05). Training-induced specific activation of AKT, S6K, and p38 MAPK was found in muscles from control mice but not in DUhTP mice (p ≤ 0.05), indicating a lack of mTORC1 and mTORC2 activation in marathon mice in response to physical exercise. While hormone-dependent mTORC1 and mTORC2 pathways in marathon mice were repressed, robust increases of Ragulator complex compounds (p ≤ 0.001) and elevated sirtuin 2 to 6 mRNA expression were observed in the DUhTP marathon mouse model (p ≤ 0.05). Activation of AMPK was not observed under the experimental conditions of the present study. Our results describe coordinated downregulation of the somatotropic pathway in long-term selected marathon mice (DUhTP), possibly via the pituitary gland and muscle interaction. Our results, for the first time, demonstrate that GH/IGF effects are repressed in a context of superior running performance in mice.

Effects of Milk or Soy Milk Combined with Mild Resistance Exercise on the Muscle Mass and Muscle Strength in Very Old Nursing Home Residents with Sarcopenia

Background and aims: Sarcopenia is recognized as a major public health issue, because it is prevalent in the elderly, especially those who live in long-term care facilities. The purpose of this study was to investigate the beneficial effects of milk or soy milk combined with resistance exercise on the muscle mass and muscle strength of individual elderly nursing home residents with sarcopenia. Methods: This study was a randomized controlled trial (clincaltrials.gov as NCT05035121) that recruited very old (>75 years) subjects with sarcopenia in a nursing home (Su-Ao and Yuanshan Branches, Taipei Veterans General Hospital) from June to December 2017. Thirty-five elderly (84.9 ± 6.1 years old) subjects were recruited and divided into three groups: control (n = 12), milk supplemented (n = 12), and soy milk supplemented (n = 11). All participants joined a mild resistance exercise training program three times a week (30 min/time). Moreover, elderly subjects in the milk and soy milk groups drank 200 mL of milk or soy milk for breakfast and as a snack after exercise. Results: After 12 weeks, compared to the baseline, calf circumferences had significantly increased in the control and soy milk groups (p = 0.0362 and p = 0.0197, respectively). Hand grip strength had significantly improved in the milk and soy milk groups (p = 0.0407 and p = 0.0096, respectively). In addition, there was no difference among the three groups. Conclusions: Mild resistance exercise combined with milk or soy milk improved the calf circumference and hand grip strength in very old nursing home residents with sarcopenia.

Exercise Effects On Cardiovascular Disease: From Basic Aspects To Clinical Evidence

Cardiovascular (CV) disease (CVD) remains the leading cause of major morbidity and CVD- and all-cause mortality in most of the world. It is now clear that regular physical activity (PA) and exercise training (ET) induces a wide range of direct and indirect physiologic adaptations and pleiotropic benefits for human general and CV health. Generally, higher levels of PA, ET, and cardiorespiratory fitness (CRF) are correlated with reduced risk of CVD, including myocardial infarction, CVD-related death, and all-cause mortality. Although exact details regarding the ideal doses of ET, including resistance and, especially, aerobic ET, as well as the potential adverse effects of extreme levels of ET, continue to be investigated, there is no question that most of the world's population have insufficient levels of PA/ET, and many also have lower than ideal levels of CRF. Therefore, assessment and promotion of PA, ET, and efforts to improve levels of CRF should be integrated into all health professionals' practices worldwide. In this state-of-the-art review, we discuss the exercise effects on many areas related to CVD, from basic aspects to clinical practice.

Effects of resistance training on muscle strength, insulin-like growth factor-1, and insulin-like growth factor-binding protein-3 in healthy elderly subjects: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Findings regarding the effects of resistance training (RT) on muscle strength, serum level of IGF-1, and its binding proteins are contradictory. To resolve this contradiction, we performed a systematic review and meta-analysis to investigate the effects of RT on muscle strength, the levels of serum IGF-1, and IGF-binding protein-3 in the elderly and aged.

MATERIALS AND METHODS

The PubMed, CINAHL, Medline, Google Scholar, and Scopus databases and reference lists of included studies were systematically searched to identify randomized controlled trials (RCTs) comparing subjects who underwent RT and control individuals up to May 15, 2020. This study was performed following the Preferred Items for Reporting of Systematic Reviews and Meta-Analyses guidelines. We identified and analyzed 11 eligible trials in this meta-analysis.

RESULTS

Pooled data displayed an overall significant elevation in IGF-1 (mean difference (MD): 17.34 ng/ml; 95% confidence interval (CI): 7.23, 27.46) and in muscle strength in leg press (SMD: 0.82; 95% CI: 0.30, 1.34) and bench press (SMD: 0.82; 95% CI: 0.42, 1.23) following RT. By contrast, the pooled estimate showed a non-significant elevation in IGFBP-3 (MD: 0.13 ng/ml; 95% CI: - 39.39, 39.65). Subgroup analysis revealed that the elevation in serum IGF-1 levels after RT was significant only in women (MD: 19.30 ng/ml); moreover, it increased after intervention durations of both > 12 weeks (MD: 21.98 ng/ml) and of ≤ 12 weeks (MD: 15.31 ng/ml).

CONCLUSION

RT was associated with elevated muscle strength. Moreover, RT was correlated with increased serum levels of IGF-1 among women and among those who received the training for ≤ 12 weeks or > 12 weeks. Further studies are required to elucidate the mechanisms underlying the impact of RT on IGF-1, IGFBP-3, and muscle strength.

Benefits of exercise training on cerebrovascular and cognitive function in ageing

Derangements in cerebrovascular structure and function can impair cognitive performance throughout ageing and in cardiometabolic disease states, thus increasing dementia risk. Modifiable lifestyle factors that cause a decline in cardiometabolic health, such as physical inactivity, exacerbate these changes beyond those that are associated with normal ageing. The purpose of this review was to examine cerebrovascular, cognitive and neuroanatomical adaptations to ageing and the potential benefits of exercise training on these outcomes in adults 50 years or older. We systematically searched for cross-sectional or intervention studies that included exercise (aerobic, resistance or multimodal) and its effect on cerebrovascular function, cognition and neuroanatomical adaptations in this age demographic. The included studies were tabulated and described narratively. Aerobic exercise training was the predominant focus of the studies identified; there were limited studies exploring the effects of resistance exercise training and multimodal training on cerebrovascular function and cognition. Collectively, the evidence indicated that exercise can improve cerebrovascular function, cognition and neuroplasticity through areas of the brain associated with executive function and memory in adults 50 years or older, irrespective of their health status. However, more research is required to ascertain the mechanisms of action.

Effects of physical activities on dementia-related biomarkers: A systematic review of randomized controlled trials

INTRODUCTION

Physical activities (PA) may lead to improved cognition in mild cognitive impairment (MCI), Alzheimer's disease (AD), and dementia. The mechanisms mediating potential PA effects are unknown. Assessment of PA effects on relevant biomarkers may provide insights into mechanisms underlying potential PA effects on cognition.

METHODS

We systematically reviewed randomized controlled trials (RCTs) that studied PA effects on biomarkers in MCI, AD, and dementia populations. We examined whether biological mechanisms were hypothesized to explain associations among PA, biomarkers, and cognitive functions. We used the PubMed database and searched for RCTs with PA until October 31, 2019.

RESULTS

Of 653 studies examining changes in biomarkers in PA trials, 18 studies met inclusion criteria for the present review. Some studies found favorable effects of PA on neurotrophic and inflammatory biomarkers. AD pathological markers were rarely investigated, with inconclusive results. Most studies were relatively small in sample size, of limited duration, and not all studies compared the changes in biomarkers between the control and experimental groups.

DISCUSSION

There is only limited use of potentially informative biomarkers in PA trials for MCI, AD, and dementia. Most studies did not examine the role of biomarkers to study associations between PA and cognitive functions in their analyses. Several potential biomarkers remain uninvestigated. Careful use of biomarkers may clarify mechanisms underlying PA effects on cognition. Our review serves as a useful resource for developing future PA RCTs aimed at improving cognitive functions in MCI, AD, and dementias.

IGF-I and IGFBP-1 in Relation to Body Composition and Physical Performance in Female Olympic Athletes

INTRODUCTION

Insulin- like growth factor-I (IGF-I) is an anabolic hormone that may affect athletic performance in female athletes, and insulin-like growth factor binding protein-1 (IGFBP-1) is an important regulator of bioactive IGF-I. There is limited knowledge of the role of endogenous IGF-I and IGFBP-1 for body composition and physical performance in female elite athletes.

PURPOSE

To examine IGF-I, age adjusted IGF-I (IGFSD), IGFBP-1 and insulin in female Olympic athletes compared with controls and different sport categories, and in relation to body composition and physical performance in the athletes.

METHODS

Female athletes (n=103) and untrained controls (n=113) were included in this cross-sectional study. Body composition was established by dual-energy X-ray absorptiometry. Serum IGF-I and IGFBP-1 were analyzed by radioimmunoassay and IGFSD was calculated. Insulin was analyzed by electrochemiluminescence immunoassay. Athletes were offered to participate in standardized physical fitness tests.

RESULTS

The athletes demonstrated significantly higher IGF-I, IGFSD and IGFBP-1 and lower insulin levels than controls (p<0.05, p<0.05, p<0.01, p<0.001 respectively). Power athletes had significantly higher IGFSD compared to both endurance and technical athletes (p<0.05, p<0.01, respectively). In athletes and controls combined, significant positive correlations were found between IGF variables and higher bone mineral density (BMD) and lean mass and lower fat percent. IGF-I was positively correlated with squat jump (r_s = 0.28, p<0.05) and IGFBP-1 correlated positively with squats (r_s =0.35, p<0.05).

CONCLUSION

We found higher IGF-I, IGFSD and IGFBP-1 in female athletes than controls, and the highest IGFSD in power athletes. IGF-I and IGFBP-1 were related to increased BMD and lean mass and lower fat percent, as well as were positively associated with physical fitness tests. Future studies are needed to elucidate if these results reflect adaptive responses to physical activity or genetic predisposition.

Biomarkers Correlate With Body Composition and Performance Changes Throughout the Season in Women's Division I Collegiate Soccer Players

The purpose of this study was to evaluate the effects of a competitive soccer season on biomarkers and performance metrics in order to determine the correlation between changes in biomarkers, body composition, and performance outcomes. Twenty-one Division 1 female collegiate soccer players were monitored throughout the 16-week season. Player workload was measured using heart rate and Global Position Satellite systems at all practices and games. Performance testing, including vertical jump, VO_2max, and 3-repetition maximum testing for bench press, squat and deadlift, occurred prior to pre-season and immediately post-season. Blood draws occurred prior to preseason and every 4-weeks thereafter, following a game. Body composition was assessed prior to the start of season (week 0) and weeks 6, 10, 14, and 17 (post-season). Delta area under the curve was calculated for biomarkers and body composition variables to account for seasonal changes adjusted for baseline. Pearson-product moment correlations were used to assess relationships with significance set at p < 0.05. Trends were considered p ≤ 0.10. No significant time main effects were seen for anabolic biomarkers (p > 0.05). Significant time effects were seen for catabolic biomarkers throughout the season (p = 0.001). No changes in body weight, VO_2max, vertical jump, and deadlift occurred. Squat and bench press improved (p = 0.01 and p = 0.02, respectively) with a decline in percent body fat (p = 0.03) and a trend for increased fat free mass (p = 0.09). Additionally, total cortisol (TCORT) negatively correlated with fat free mass (r = −0.48; p = 0.03) and positively correlated with VO_2max (r = 0.47; p = 0.04). A trend was shown for a positive correlation between both TCORT and free cortisol (FCORT) and percent body fat (r = 0.39; r = 0.40; p = 0.08, respectively). IGF-1 and growth hormone positively correlated to deadlift (r = 0.57; P = 0.02 and r = 0.59; p = 0.03), whereas creatine kinase showed a trend for a positive correlation with deadlift (r = 0.49; p = 0.06). IL-6 negatively correlated with bench press (r = −0.53; p = 0.03). These findings support a relationship between biomarkers, performance outcomes, and body composition. Biomarker monitoring may be useful to detect individual player's physiological response to an athletic season and may help provide insights in efforts to optimize performance outcomes.

Role of Regular Physical Activity in Neuroprotection against Acute Ischemia

One of the major obstacles that prevents an effective therapeutic intervention against ischemic stroke is the lack of neuroprotective agents able to reduce neuronal damage; this results in frequent evolution towards a long-term disability with limited alternatives available to aid in recovery. Nevertheless, various treatment options have shown clinical efficacy. Neurotrophins such as brain-derived neurotrophic factor (BDNF), widely produced throughout the brain, but also in distant tissues such as the muscle, have demonstrated regenerative properties with the potential to restore damaged neural tissue. Neurotrophins play a significant role in both protection and recovery of function following neurological diseases such as ischemic stroke or traumatic brain injury. Unfortunately, the efficacy of exogenous administration of these neurotrophins is limited by rapid degradation with subsequent poor half-life and a lack of blood-brain-barrier permeability. Regular exercise seems to be a therapeutic approach able to induce the activation of several pathways related to the neurotrophins release. Exercise, furthermore, reduces the infarct volume in the ischemic brain and ameliorates motor function in animal models increasing astrocyte proliferation, inducing angiogenesis and reducing neuronal apoptosis and oxidative stress. One of the most critical issues is to identify the relationship between neurotrophins and myokines, newly discovered skeletal muscle-derived factors released during and after exercise able to exert several biological functions. Various myokines (e.g., Insulin-Like Growth Factor 1, Irisin) have recently shown their ability to protects against neuronal injury in cerebral ischemia models, suggesting that these substances may influence the degree of neuronal damage in part via inhibiting inflammatory signaling pathways. The aim of this narrative review is to examine the main experimental data available to date on the neuroprotective and anti-ischemic role of regular exercise, analyzing also the possible role played by neurotrophins and myokines.

Combination of resistance and aerobic exercise for six months improves bone mass and physical function in HIV infected individuals: A randomized controlled trial

To evaluate the effect of combined resistance and aerobic training (RT+AT) on regional bone mineral density (BMD) and physical performance in people living with HIV (PLWH). Forty PLWH (20 men and 20 women) were randomized into RT+AT group (n = 20; age = 38.3 ± 4.9) or non-exercise control group (n = 20; age = 37.9 ± 5.1). The RT+AT group was required to perform a nonlinear periodized resistance training program targeting large muscle groups followed by 20 min aerobic exercise at 65-80% of maximal heart rate. Participants in RT+AT performed three supervised sessions per week for 6-months, whereas participants in the control group were instructed to continue with their current lifestyle habits. The primary outcome was bone mineral density (lumbar spine (L2-L4), femoral neck, and distal 1/3 radius). Secondary outcomes included physical function, anthropometry, inflammatory markers, and growth factors. The RT+AT group demonstrated a significant increase in BMD at follow-up for the Lumbar spine (L2-L4), femoral neck, and 1/3 radius (all, P < .05), and There were no gender differences in the training response between men and women for any of the BMD regions. Similar findings were also observed for lean body mass, IGF1and Adiponectin (P < .001). We observed a decrease in percent body fat, fat mass, IL-6, TNF-α, and myostatin in the RT+AT group (P < .001). Finally, there was a significant increase in handgrip strength and gait speed for both women and men in the RT+AT group (P < .001). A combination of resistance and aerobic training appears to be a feasible and effective means for counteracting bone loss and improving various inflammatory markers, physical function, and growth hormones in PLWH.

Does Aerobic and Resistance Exercise Influence Episodic Memory through Unique Mechanisms?

Aerobic and resistance exercise (acute and chronic) independently and collectively induce beneficial responses in the brain that may influence memory function, including an increase in cerebral blood flow, neurogenesis, neuroelectrical alterations, and protein production. However, whether aerobic and resistance exercise improve memory via similar or distinct mechanisms has yet to be fully explained. Here, we review the unique influence of aerobic and resistance exercise on neural modulation, proteins, receptors, and ultimately, episodic memory. Resistance training may optimize neural communication, information processing and memory encoding by affecting the allocation of attentional resources. Moreover, resistance exercise can reduce inflammatory markers associated with neural communication while increasing peripheral and central BDNF (brain-derived neurotrophic factor) production. Aerobic training increases hippocampal levels of BDNF and TrkB (Tropomyosin receptor kinase B), protein kinases and glutamatergic proteins. Likewise, both aerobic and anaerobic exercise can increase CREB (cAMP response element-binding protein) phosphorylation. Thus, we suggest that aerobic and resistance exercise may influence episodic memory via similar and, potentially, distinct mechanisms.

Insulin and Growth Hormone Balance: Implications for Obesity

Disruption of endocrine hormonal balance (i.e., increased levels of insulin, and reduced levels of growth hormone, GH) often occurs in pre-obesity and obesity. Using distinct intracellular signaling pathways to control cell and body metabolism, GH and insulin also regulate each other's secretion to maintain overall metabolic homeostasis. Therefore, a comprehensive understanding of insulin and GH balance is essential for understanding endocrine hormonal contributions to energy storage and utilization. In this review we summarize the actions of, and interactions between, insulin and GH at the cellular level, and highlight the association between the insulin/GH ratio and energy metabolism, as well as fat accumulation. Use of the [insulin]:[GH] ratio as a biomarker for predicting the development of obesity is proposed.

Can IGF-1 Serum Levels Really be Changed by Acute Physical Exercise? A Systematic Review and Meta-Analysis

Background: Physical exercise plays an important role in metabolic health, especially in the insulin-like growth factor-1 (IGF-1) system. The objective of this study was to perform a systematic review and meta-analysis to evaluate the effects of a single endurance and resistance exercise session on IGF-1 serum. Methods: The systematic review was performed in SPORTDiscus, MEDLINE, PubMed, and Google Scholar databases. All analyses are based on random-effect models. The study identified 249 records of which 21 were included. Results: There was an effect of endurance exercise on total IGF-1 (P = .01), but not for free IGF-1 (P = .36). Resistance exercise similarly only affected total IGF-1 (P = .003) and not free IGF-1 (P = .37). The effect size indicated that total IGF-1 is more affected (ES = 0.81) by endurance than by resistance exercise (ES = 0.46). The present study showed that IGF-1 serum concentrations are altered by exercise type, but in conditions which are not well-defined. Conclusions: The systematic review and meta-analysis suggest that there is no determinant in serum IGF-1 changes for the exercise load characteristic. Therefore, physical exercise may be an alternative treatment to control changes in IGF-1 metabolism and blood concentration.

Effects of a home-based exercise program on the insulin-like growth factor axis in patients operated for colorectal cancer in Sweden: Results from the randomised controlled trial PHYSSURG-C

OBJECTIVES

We report results from a subgroup within the ongoing PHYSSURG-C trial with the aim to examine effects of exercise on IGF-1 and IGFBP-3 in patients undergoing colorectal cancer surgery.

DESIGN

Randomised controlled trial.

SETTING

A Swedish university hospital.

PARTICIPANTS

Between 2015 and 2016, 217 patients were enrolled (I = 106, C = 111), with 122 patients that had given blood samples at baseline and at least at one follow-up (I = 51, C = 71). Patients 20 year or older with colorectal cancer were eligible. Exclusion criteria were emergency surgery, local surgery, language problems or inability to perform intervention.

INTERVENTIONS

Patients were computer-randomised to either a daily home-based aerobic exercise intervention (I), or to usual care (C). The intervention lasted two weeks before surgery and four weeks after discharge from hospital and consisted of medium-intensity aerobic exercise and inspiratory muscle training. Circulating concentrations of IGF-1 and IGFBP-3 were determined by blinded personnel at baseline, time of surgery and 4-6 weeks postoperatively.

PRIMARY AND SECONDARY OUTCOME MEASURES

The outcome of this subpopulation report was change in IGF-1/IGFBP-3 ratio, IGF-1 and IGFBP-3 concentrations from baseline to surgery, and 4-6 weeks postoperatively.

RESULTS

The IGF-1/IGFBP-3 ratio increased from baseline to surgery by 11% in I and 8% in C with no difference between groups (I vs. C: 1.04, 95%CI: 0.97-1.11; p = 1.000). Postoperative change was 5% in I and 3% in C with no difference between groups (I vs. C:1.03, 95%CI: 0.96-1.10; p = 1.000). Results concerning IGF-1 and IGFBP-3 also showed statistically significant dynamics over time with no difference between groups. No adverse events were reported.

CONCLUSIONS

The home-based exercise program in our trial did not have any effect on IGF-1, or IGFBP-3.

TRIAL REGISTRATION

The study was registered at ClinicalTrials.gov with identifier NCT02299596. This work was funded externally.

Microdialysis-Assessed Exercised Muscle Reveals Localized and Differential IGFBP Responses to Unilateral Stretch Shortening Cycle Exercise

Microdialysis allows for a preview into local muscle metabolism and can provide physiological insight that blood measurements cannot. Purpose: To examine the potential differential IGF-I system regulation in interstitial fluid during unilateral stretch shortening cycle exercise. Methods: 10 men (26 ± 7 year) performed unilateral jumping [stretch shortening cycle (SSC) exercise at 50% of optimal jump height] until volitional fatigue on a sled apparatus. Biological sampling took place using a catheter inserted into an antecubital vein (serum), and 100 kDa microdialysis probes inserted into the thigh muscle of each exercise/control leg (dialysate). Serum was drawn before (Pre; -3 h) and after SSC [Post I (+0 h), II (+3 h), or III (+20 h)]; dialysate was sampled for 2 h before (Pre), during/immediately after (Ex), and 3 h into recovery (Rec) following SSC. IGF-I system parameters (free/total IGF-I and IGFBPs 1-6) were measured with immunoassays. Interstitial free IGF-I was estimated from dialysate IGF-I and relative recovery (ethanol) correction. Data were analyzed with repeated measures ANOVA. Results: Serum total IGF-I remained elevated +3 h (Post II: 182.8 ± 37.6 vs. Pre: 168.3 ± 35.0 ng/mL, p < 0.01), but returned to baseline by +20 h (Post III vs. Pre, p = 0.31). No changes in serum free IGF-I were noted. Serum BP-1 and -3 increased over baseline, but not until + 20 h after SSC (Post III vs. Pre: 7.6 ± 4.9 vs. 3.7 ± 2.3 and 1,048.6 ± 269.2 vs. 891.4 ± 171.2 ng/mL, respectively). We observed a decreased serum BP-6 +3 h after SSC (p < 0.01), followed by a return to baseline at +20 h (p = 0.64 vs. Pre). There were no exercise-induced changes in serum BP-2, -4, or -5. Unlike serum, there were no changes in dialysate or interstitial free IGF-I in either leg (p > 0.05). Dialysate BP-1 remained increased in both exercise and control legs through 3 h into recovery (Rec vs. Pre, p < 0.01). Dialysate BP-3 also demonstrated a prolonged elevation over Pre SSC concentrations, but in the exercise leg only (Ex and Rec vs. Pre, p < 0.04). We observed a prolonged decrease in dialysate BP-5 (Ex and Rec vs. Pre, p < 0.03) and an increase in BP-4 IP in the exercise leg only. There were no changes relative to Pre SSC in dialysate BP-2 or -6. Conclusions: Unilateral exercise drives differential regulation of the IGF-I system at both local and systemic levels. More specifically, this is the first study to demonstrate that localized exercise increases IGFBP-3, IGFBP-4 and decreases in IGFBP-5 in muscle interstitial fluid.

Growth Hormone and Insulin-like Growth Factor-I Molecular Weight Isoform Responses to Resistance Exercise Are Sex-Dependent

Purpose: To determine if acute resistance exercise-induced increases in growth hormone (GH) and insulin-like growth factor-I (IGF-I) were differentially responsive for one or more molecular weight (MW) isoforms and if these responses were sex-dependent. Methods: College-aged men (n = 10) and women (n = 10) performed an acute resistance exercise test (ARET; 6 sets, 10 repetition maximum (10-RM) squat, 2-min inter-set rest). Serum aliquots from blood drawn Pre-, Mid-, and Post-ARET (0, +15, and +30-min post) were processed using High Performance Liquid Chromatography (HPLC) fractionation and pooled into 3 MW fractions (Fr.A: >60; Fr.B: 30-60; Fr.C: <30 kDa). Results: We observed a hierarchy of serum protein collected among GH fractions across all time points independent of sex (Fr.C > Fr.A > Fr.B, p ≤ 0.03). Sex × time interactions indicated that women experienced earlier and augmented increases in all serum GH MW isoform fraction pools (p < 0.05); however, men demonstrated delayed and sustained GH elevations (p < 0.01) in all fractions through +30-min of recovery. Similarly, we observed a sex-independent hierarchy among IGF-I MW fraction pools (Fr.A > Fr.B > Fr.C, p ≤ 0.01). Furthermore, we observed increases in IGF-I Fr. A (ternary complexes) in men only (p ≤ 0.05), and increases in Fr.C (free/unbound IGF-I) in women only (p ≤ 0.05) vs. baseline, respectively. Conclusions: These data indicate that the processing of GH and IGF-I isoforms from the somatotrophs and hepatocytes are differential in their response to strenuous resistance exercise and reflect both temporal and sex-related differences.

Active Commute in Relation to Cognition and Academic Achievement in Children and Adolescents: A Systematic Review and Future Recommendations

Active commuting to school (ACS) is an important source of physical activity among children. Recent research has focused on ACS and its benefits on cognition and academic achievement (AA), factors important for success in school. This review aims to synthesize literature on the relationship between ACS and cognition or AA among children and adolescents. Peer-reviewed articles in PubMed, Web of Science, PsycINFO and Cochrane Library assessing ACS with cognition and/or AA among children, until February 2019, were selected. Twelve studies across nine countries (age range 4–18.5 years) were included. One study used accelerometers, whereas all others used self-report measures of ACS. A wide range of objective assessments of cognitive functioning and AA domains were used. Five among eight studies, and four among six found a positive relationship between ACS and cognitive or AA measure, respectively. Four studies found dose–response relationships, and some studies found sex differences. The quantitative analysis found that ACS was not significantly associated with mathematics score (odds ratio = 1.18; CI = 0.40, 3.48). Findings are discussed in terms of methodological issues, potential confounders, and the strength of the evidence. Future studies should conduct longitudinal studies and use objective measures of ACS to understand this relationship further.

The effect of 30-m repeated sprint exercise on muscle damage indicators, serum insulin-like growth factor-Iand cortisol

Study aim: The purpose of this study was to examine the effects of arepeated sprint exercise protocol on muscle damage indicators, serum IGF-Iand cortisol levels.

Material and methods: Nine trained male subjects (age 23.3 ± 3.6 years) completed arepeated sprint protocol consisting of two sets of 10 × 30-m maximal sprints with 30 s of active recovery between sprints and 5 min of passive recovery between sets. The isometric strength and flexibility were measured before, immediately after and 24 hours after exercise. 30-m maximal sprint time was measured before and 24 hours after exercise. Blood samples were taken before, immediately after and 24 hours after exercise.

Results: Isometric strength and flexibility were significantly decreased after exercise and 24 hours after exercise (p < 0.05). 30-m sprint time was significantly increased 24 hours after exercise (p < 0.05). Asignificant increase in serum lactate dehydrogenase, IGF-Iand cortisol were found after exercise (p < 0.05). Serum creatine kinase increased significantly immediately after and 24 hours after exercise compared to pre-exercise values (p < 0.05).

Conclusion: Our data show that due to increased serum IGF-Ilevel, repeated sprint exercise may have anabolic effects as well as traumatic effects on the muscles.

Physical Activity and the Occurrence of Postnatal Depression-A Systematic Review

Background and Objectives: During pregnancy and the postnatal period many changes occur in a woman's body, both in mental and physical spheres. The birth of a child and a new role-of a mother-can sometimes be associated with numerous negative emotions, uncertainty, fear, anxiety, disgust, depression, or sadness. In the puerperium period, the development of baby blues or postpartum depression may occur. Postpartum depression develops within one month of childbirth and may last up to one year. Depressive disorders that may develop in a young mother affect both her and the newborn's health. That is why it is so important to try to search for factors that could significantly reduce the likelihood of developing depression in this period. The study aims at assessing the relationship between physical activity during pregnancy and puerperium or in the postpartum and the development of postnatal depression. Materials and Methods: A review of the literature was carried out in the Medline-PubMed database. The search terms were "pregnancy" AND "physical activity AND postpartum depression". The study included only English-language publications published in the period 2000-2018. Results: A total of 216 references were found. After establishing the inclusion and exclusion criteria based on the analysis of titles and abstracts, 173 articles were excluded from the review. A total of 43 publications were read in full. Finally, 16 articles were included in the review. It was shown that regular physical activity during pregnancy, pregnancy, and puerperium, or in the postnatal period itself as compared to inactivity, reduces the risk of developing depression in pregnant women and after the birth of a child. Conclusions: Physical activity can be an essential factor in the prevention of depressive disorders of women in the postnatal period.

Effects of Boxing Matches on Metabolic, Hormonal, and Inflammatory Parameters in Male Elite Boxers

Background and objectives: Boxing is a popular combat sport that requires high intensity and cooperation. However, there are limited data about the influence of boxing matches on blood parameters. The purpose of the present study was to investigate the match-induced changes in the metabolic, hormonal, and inflammatory status in male elite boxers. Materials and methods: High-level 20 male boxers with more than 5 years experience in boxing voluntarily participated in this study. Venous blood samples of the boxers, before and after combat, were taken for determination of the plasma parameters. Results: Our results indicated that a 9-min boxing match caused significant increases in plasma energy fuels (glucose and lactate), metabolic hormones (insulin, adrenocorticotropic hormone (ACTH), cortisol, and growth hormone), inflammatory markers (interleukin-1β (IL-1β), interleukin-6 (IL-6) and tumor necrosis factor alpha (TNF-α)), muscle damage indicators (alanine aminotransferase (ALT) and aspartate aminotransferase (AST)), and oxidative stress marker (SOD). A decrease in total oxidant status (TOS) was also considered. However, there were no significant alterations in the plasma levels of androgenic hormone (free and total testosterone), anabolic hormone (IGF-1), lipids (total cholesterol, triglyceride, high-density lipoprotein (HDL), and low-density lipoprotein (LDL)), kidney function markers (creatinine and urea), and minerals (iron (Fe) and magnesium (Mg)). Conclusion: Elevations in the level of energy fuels and metabolic hormones of the boxers could be taken as a reflection of high-energy turnover during combat performance. The increases in inflammatory and tissue damage indicators may possibly be an indication of traumatic injury. Understanding the biochemical changes that occur during boxing match could be valuable to optimize the performance improvement of the athletes.

Physical exercise and Prader-Willi syndrome: A systematic review

OBJECTIVE

The aim of this systematic review was to summarize evidence on the acute responses of individuals with Prader-Willi syndrome (PWS) to physical exercise, and on the effectiveness of long-term exercise interventions to improve the clinical manifestations of this syndrome.

DESIGN/METHODS

Relevant articles were identified in the electronic databases PubMed, Medline, CINAHL and SPORTDiscus (from inception to December 2018). Twenty-two studies including a total of 356 patients with PWS met all inclusion criteria and were included in the review.

RESULTS

Patients with PWS present with a decreased physical performance and impaired cardiorespiratory (maximal oxygen consumption, heart rate recovery after exercise) and hormonal (growth hormone release) responses to exercise. Most long-term exercise interventions have proven to decrease body mass while improving physical performance. Some benefits have also been reported in biochemical (glucose homeostasis, lipid profile) and biomechanical (gait pattern) variables, although there is controversy regarding the effects on body composition. No exercise-related adverse events have been reported in patients with PWS.

CONCLUSION

Physical exercise seems to be safe and effective for improving several phenotypes in PWS, notably physical fitness. However, further research is needed to confirm these results and especially to corroborate whether exercise per se or combined with dietary intervention is an effective coadjuvant treatment for reducing body mass in these patients.

Effects of blood flow restriction during moderate-intensity eccentric knee extensions

We investigated if blood flow restriction (BFR, cuff pressure 20 mmHG below individual occlusion pressure) increases metabolic stress, hormonal response, release of muscle damage markers, and muscle swelling induced by moderate-intensity eccentric contractions. In a randomized, matched-pair design, 20 male subjects (25.3 ± 3.3 years) performed four sets of unilateral eccentric knee extensions (75% 1RM) to volitional failure with (IG) or without (CG) femoral BFR. Despite significant differences of performed repetitions between IG (85.6 ± 15.4 repetitions) and CG (142.3 ± 44.1 repetitions), peak values of lactate (IG 7.0 ± 1.4 mmol l-1, CG 6.9 ± 2.7 mmol l-1), growth-hormone (IG 4.9 ± 4.8 ng ml-1, CG 5.2 ± 3.5 ng ml-1), insulin-like growth factor 1 (IG 172.1 ± 41.9 ng ml-1, CG 178.7 ± 82.1 ng ml-1), creatine-kinase (IG 625.5 ± 464.8 U l-1, CG 510.7 ± 443.5 U l-1), the absolute neutrophil count (IG 7.9 ± 1.3 103 µl-1, CG 8.7 ± 2.0 103 µl-1), induced muscle swelling of rectus femoris and vastus lateralis and perceived pain did not differ. The present data indicate that BFR is suitable to intensify eccentric exercises.

Circulating insulin-like growth factor I modulates mood and is a biomarker of vulnerability to stress: from mouse to man

Individual susceptibility to anxiety disorders after maladaptive responses to stress is not well understood. We now report that while exploring stress responses in mice after traumatic brain injury (TBI), a condition associated to stress susceptibility, we observed that the anxiogenic effects of either TBI or exposure to life-threatening experiences (predator) were blocked when both stressors were combined. Because TBI increases the entrance into the brain of serum insulin-like growth factor I (IGF-I), a known modulator of anxiety with a wide range of concentrations in the human population, we then determined whether circulating IGF-I is related to anxiety measures. In mice, anxiety-like responses to predator were inversely related to circulating IGF-I levels. Other indicators of mood regulation such as sensitivity to dexamethasone suppression and expression levels of blood and brain FK506 binding protein 5 (FKBP5), a co-chaperone of the glucocorticoid receptor that regulates its activity, were also associated to circulating IGF-I. Indeed, brain FKBP5 expression in mice was stimulated by IGF-I. In addition, we observed in a large human cohort (n = 2686) a significant relationship between plasma IGF-I and exposure to recent stressful life events, while FKBP5 expression in blood cells was significantly associated to plasma IGF-I levels. Collectively, these data indicate that circulating IGF-I appears to be involved in mood homeostasis across different species. Furthermore, the data in mice allow us to indicate that IGF-I may be acting at least in part by modulating FKBP5 expression.

Effects of Cyclic Mechanical Stretch on the Proliferation of L6 Myoblasts and Its Mechanisms: PI3K/Akt and MAPK Signal Pathways Regulated by IGF-1 Receptor

Myoblast proliferation is crucial to skeletal muscle hypertrophy and regeneration. Our previous study indicated that mechanical stretch altered the proliferation of C2C12 myoblasts, associated with insulin growth factor 1 (IGF-1)-mediated phosphoinositide 3-kinase (PI3K)/Akt (also known as protein kinase B) and mitogen-activated protein kinase (MAPK) pathways through IGF-1 receptor (IGF-1R). The purpose of this study was to explore the same stretches on the proliferation of L6 myoblasts and its association with IGF-1-regulated PI3K/Akt and MAPK activations. L6 myoblasts were divided into three groups: control, 15% stretch, and 20% stretch. Stretches were achieved using FlexCell Strain Unit. Cell proliferation and IGF-1 concentration were detected by CCK8 and ELISA, respectively. IGF-1R expression, and expressions and activities of PI3K, Akt, and MAPKs (including extracellular signal-regulated kinases 1 and 2 (ERK1/2) and p38) were determined by Western blot. We found that 15% stretch promoted, while 20% stretch inhibited L6 myoblast proliferation. A 15% stretch increased IGF-1R level, although had no effect on IGF-1 secretion of L6 myoblasts, and PI3K/Akt and ERK1/2 (not p38) inhibitors attenuated 15% stretch-induced pro-proliferation. Exogenous IGF-1 reversed 20% stretch-induced anti-proliferation, accompanied with increases in IGF-1R level as well as PI3K/Akt and MAPK (ERK1/2 and p38) activations. In conclusion, stretch regulated L6 myoblasts proliferation, which may be mediated by the changes in PI3K/Akt and MAPK activations regulated by IGF-1R, despite no detectable IGF-1 from stretched L6 myoblasts.

The Role of MicroRNAs in the Cardiac Response to Exercise

Noncoding microRNAs (miRNAs) have emerged as central regulators of cardiac biology, modulating cardiac development and the response to pathological stress in disease. Although less well developed, emerging evidence suggests miRNAs are likely also important in the heart's response to the physiological stress of exercise. Given the well-recognized cardiovascular benefits of exercise, elucidating the contribution of miRNAs to this response has the potential not only to reveal novel aspects of cardiovascular biology but also to identify new targets for therapeutic intervention that may complement those discovered through studies of diseased hearts. Here, we first provide an overview of the cardiovascular effects of exercise as well as some of the major protein signaling mechanisms contributing to these effects. We then review the evidence that both cardiac and circulating miRNAs are dynamically regulated by exercise and regulate these mechanisms and phenotypes.

Tribulus terrestris extracts alleviate muscle damage and promote anaerobic performance of trained male boxers and its mechanisms: Roles of androgen, IGF-1, and IGF binding protein-3

PURPOSE

To investigate the effects of Tribulus terrestris (TT) extracts on muscle mass, muscle damage, and anaerobic performances of trained male boxers and its mechanisms: roles of plasma androgen, insulin growth factor 1 (IGF-1), and IGF-1 binding protein-3 (IGFBP-3).

METHODS

Fifteen male boxers were divided into exercise group (E, n = 7) and exercise plus TT group (E + TT, n = 8). The 2 groups both undertook 3-week high-intensity and 3-week high-volume trainings separated by a 4-week rest. TT extracts (1250 mg/day) were orally administered by boxers in E + TT group. TT extract compositions were detected by UHPLC-Q-TOF/MS. Before and at the end of the 2 trainings, muscle mass, anaerobic performance, and blood indicators were explored.

RESULTS

Compared with E group, decreases of plasma CK (1591.5 ± 909.6 U/L vs. 2719.9 ± 832.5 U/L) and IGFBP-3 (3075.5 ± 1072.5 ng/mL vs. 3950.8 ± 479.3 ng/mL) as well as increases of mean power (MP, 459.4 ± 122.3 W vs. 434.6 ± 69.5 W) and MP/body weight (MP/BW, 7.5 ± 0.9 W/kg vs. 7.1 ± 1.1 W/kg) were detected in E + TT group after a high-intensity training. For high-volume training, reduction of IGFBP-3 (2946.4 ± 974.1 ng/mL vs. 3632.7 ± 470.1 ng/mL) and increases of MP (508.7 ± 103.2 W vs. 477.8 ± 49.9 W) and MP/BW (8.2 ± 0.3 W/kg vs. 7.5 ± 0.9 W/kg) were detected in E + TT group, compared with E group. Muscle mass, blood levels of testosterone, dihydrotestosterone (DHT), and IGF-1 were not signifiantly changed between the 2 groups.

CONCLUSION

Taking 1250 mg capsules containing TT extracts did not change muscle mass and plasma levels of testosterone, DHT, and IGF-1 but significantly alleviated muscle damage and promoted anaerobic performance of trained male boxers, which may be related to the decrease of plasma IGFBP-3 rather than androgen in plasma.

Enhanced Strength and Sprint Levels, and Changes in Blood Parameters during a Complete Athletics Season in 800 m High-Level Athletes

The purpose of this study was to analyze changes in sprint, strength, hematological, and hormonal parameters in high-level 800 m athletes during a complete athletics season. Thirteen male athletes of national and international level in 800 m (personal best ranging from 1:43 to 1:58 min:ss) participated in this study. A total of 5 tests were conducted during a complete athletics season. Athletes performed sprint tests (20 and 200 m), countermovement jump (CMJ), jump squat (JS), and full squat (SQ) tests. Blood samples (red and white blood profile) and hormones were collected in test 1 (T1), test 3 (T3), and test 5 (T5). A general increase in the performance of the strength and sprint parameters analyzed (CMJ, JS, SQ, 20 m, and 200 m) during the season was observed, with a significant time effect in CMJ (P < 0.01), SQ (P < 0.01), and 200 m (P < 0.05). This improvement was accompanied by a significant enhancement of the 800 m performance from T3 to T5 (P < 0.01). Significant changes in some hematological variables: hematocrit (Hct) (P < 0.01), mean corpuscular volume (MCV) (P < 0.001), mean corpuscular hemoglobin content (MCHC) (P < 0.001), white blood cells count (WBC) (P < 0.05), neutrophils (P < 0.05), monocytes (P < 0.05), and mean platelet volume (MPV) (P < 0.05) were observed throughout the season. The hormonal response and creatin kinase (CK) did not show significant variations during the season, except for insulin-like growth factor I (IGF-1) (P < 0.05). In conclusion, our results suggest the importance of strength levels in middle-distance athletes. On the other hand, variations in some hematological parameters and a depression of the immune system occurred during the season. Therefore, monitoring of the mechanical, hematological and hormonal response in athletes may help coaches and athletes to optimize the regulation of training contents and may be useful to diagnose states of overreaching or overtraining in athletes throughout the season.

Combined sprint and resistance training abrogates age differences in somatotropic hormones

The aim of this investigation was to compare serum growth hormone (GH), insulin-like growth factor-1 (IGF-1) and insulin-like growth factor-binding protein-3 (IGFBP-3) in response to a combined sprint and resistance training (CSRT) program in young and middle-aged men.Thirty-eight healthy, moderately trained men participated in this study. Young and middle-aged men were randomly assigned to, a young training group (YT = 10, 21.4±1.2yrs) ora young control group (YC = 9, 21.6±1.8 yrs), a middle-aged training group (MAT = 10, 40.4±2.1 yrs) or a middle-aged control group (MAC = 9, 40.5±1.8 yrs). Participants performed the Wingate Anaerobic Test (WAnT) before and after a 13-week CSRT program (three sessions per week). Blood samples were collected at rest, after warm-up, immediately post-WAnT, and 10 min post-WAnT. CSRT induced increases in GH at rest and in response to the WAnT in YT and MAT (P<0.05). CSRT-induced increases were observed for IGF-1 and IGFBP-3 at rest in MAT only (P<0.05). Pre-training, GH, IGF-1 and IGFBP-3 were significantly higher at rest and in response to the WAnT in young participants as compared to their middle-aged counterparts (P<0.05). Post-training, YT and MAT had comparable basal GH (P>0.05). In response to the WAnT, amelioration of the age-effect was observed between YT and MAT for IGF-1 and IGF-1/IGFBP-3 ratio following CSRT (P>0.05). These data suggest that CSRT increases the activity of the GH/IGF-1 axis at rest and in response to the WAnT in young and middle-aged men. In addition, CSRT reduces the normal age-related decline of somatotropic hormones in middle-age men.

MUSCLE STRENGTH, GH AND IGF-1 IN OLDER WOMEN SUBMITTED TO LAND AND AQUATIC RESISTANCE TRAINING

ABSTRACT Introduction: Aging leads to decline in multiple organ systems associated to hormone alterations and loss of muscle mass and strength. Objective: To evaluate the effects of land and water resistance training on muscle strength, basal serum levels of GH, IGF-1, and IGFBP3 in elderly women. Methods: Subjects were distributed in three groups: land resistance training (LRT; n=10; age: 66.10±2.77 years), water resistance training (WRT; n=10; age: 67.10±3.54 years) and control (CG; n=10; age: 68.80±5.41 years). Muscle strength was assessed with the 1-RM test in bench press (BP) and leg press (LP) exercises. Serum levels of GH, IGF-1, and IGFBP3 were analyzed by chemiluminescence. Results: Repeated measures ANOVA showed elevated muscle strength in the BP only in LRT (D%=60.2%; p=0.0001) when compared to the CG (D%=46.73%, p=0.0001) and WRT (D%=32.49%, p=0.004). LRT and WRT increased muscle strength in LP (D%LRT=57.14%; p=0.004; D%WRT=42.3%; p=0.033). There was an increase in LRT and WRT in the LP when compared to CG (D%=45.59%, p=0.019; D%=43.97%, p=0.026, respectively). IGF-1 was elevated only in LRT (D%=49.72%, p=0.004) from pre- to post-test and when compared to WRT (D%=56.76%, p=0.002) and CG (D%=74.63%, p=0.0001). IGFBP3 levels showed that only WRT increased (D%=26.79%, p=0.044) from pre- to post-test. The IGF-1/IGFBP3 ratio demonstrated that LRT reached intragroup elevation (D%=52.66%, p=0.002) and when compared to WRT (D%=94.11%, p=0.0001) and CG (D%=73.45%, p=0.0001). There was no significant difference in GH. Conclusion: Land resistance training may provide better anabolic effects in elderly women.

Role of androgen receptor on cyclic mechanical stretch-regulated proliferation of C2C12 myoblasts and its upstream signals: IGF-1-mediated PI3K/Akt and MAPKs pathways

OBJECTS

To detect the effects of androgen receptor (AR) on cyclic mechanical stretch-modulated proliferation of C2C12 myoblasts and its pathways: roles of IGF-1, PI3K and MAPK.

METHODS

C2C12 were randomly divided into five groups: un-stretched control, six or 8 h of fifteen percent stretch, and six or 8 h of twenty percent stretch. Cyclic mechanical stretch of C2C12 were completed using a computer-controlled FlexCell Strain Unit. Cell proliferation and IGF-1 concentration in medium were detected by CCK8 and ELISA, respectively. Expressions of AR and IGF-1R, and expressions and activities of PI3K, p38 and ERK1/2 in stretched C2C12 cells were determined by Western blot.

RESULTS

①The proliferation of C2C12 cells, IGF-1 concentration in medium, expressions of AR and IGF-1R, and activities of PI3K, p38 and ERK1/2 were increased by 6 h of fifteen percent stretch, while decreased by twenty percent stretch for six or 8 h ②The fifteen percent stretch-increased proliferation of C2C12 cells was reversed by AR inhibitor, Flutamide. ③The increases of AR expression, activities of PI3K, p38 and ERK1/2 resulted from fifteen percent stretch were attenuated by IGF-1 neutralizing antibody, while twenty percent stretch-induced decreases of the above indicators were enhanced by recombinant IGF-1. ④Specific inhibitors of p38, ERK1/2 and PI3K all decreased the expression of AR in fifteen percent and twenty percent of stretched C2C12 cells.

CONCLUSIONS

Cyclic mechanical stretch modulated the proliferation of C2C12 cells, which may be attributed to the alterations of AR via IGF-1-PI3K/Akt and IGF-1-MAPK (p38, ERK1/2) pathways in C2C12 cells.

The function of androgen/androgen receptor and insulin growth factor‑1/insulin growth factor‑1 receptor on the effects of Tribulus terrestris extracts in rats undergoing high intensity exercise

Our previous study demonstrated that treatment with Tribulus terrestris (TT) extracts (120 mg/kg) promoted the muscle weight gain and performance of rats undergoing high intensity exercise. The present study was designed to explore the mechanisms underlying the effect of treatment with TT extracts and the involvement of androgens, the androgen receptor (AR), insulin growth factor‑1 (IGF‑1) and the IGF‑1 receptor (IGF‑1R). A total of 32 Sprague‑Dawley rats were randomly divided into groups as follows: Control; TT, treated with TT extracts, E, high intensity exercise; E+TT, high intensity exercise plus TT treatment. The rats of the E and E+TT groups underwent high intensity exercise with a progressively increasing load for 5 weeks, and TT extracts were intragastrically administered in the TT and E+TT rats 30 min prior to training. TT extract composition was analyzed using ultra‑high performance liquid chromatography‑quadrupole‑time of flight mass spectrometry. Testosterone and IGF‑1 plasma levels and AR, IGF‑1R and myosin heavy chain (MHC) protein levels in muscles were determined by ELISA and western blotting, respectively. The saponins tigogenin and diosgenin comprised ~71.35% of the total peak area. Compared with the E group, TT extracts increased the testosterone and IGF‑1 plasma levels, and AR, IGF‑1R and MHC protein levels in the gastrocnemius of rats undergoing high intensity exercise, accompanied with increased body weight and gastrocnemius weight. In conclusion, the effect of TT extracts on the performance of high intensity exercise rats may be attributed to increased levels of circulating testosterone and IGF‑1 and increased AR and IGF‑1R protein expression levels in the gastrocnemius, resulting in increased muscle weight and increased MHC in the gastrocnemius. The present study provided preliminary evidence supporting the use of TT extracts as a dietary supplement for the promotion of skeletal muscle mass increase and the enhancement of athletic performance in humans performing high intensity exercise.