Associations of apelin, leptin, irisin, ghrelin, insulin, glucose levels, and lipid parameters with physical activity during eight weeks of regular exercise training

Impact of Combined Aerobic Training and Magnesium Supplementation on Serum Biomarkers and microRNA-155 and microRNA-21 Expression in Adipose Tissue of Type 2 Diabetic Rats: An Eight-Week Interventional Study

BACKGROUND

Type 2 diabetes mellitus (T2DM) is a complex metabolic disorder characterized by insulin resistance and chronic inflammation. Aerobic training (AT) and magnesium supplementation (Mg) have both been independently shown to have beneficial effects on glucose control and insulin sensitivity in individuals with T2DM. However, the potential synergistic effects of combining AT and Mg supplementation have not been extensively studied. This study aimed to investigate the effects of an 8-week AT and Mg supplementation on serum levels of insulin, glucose, leptin, adiponectin, TNF-α, IL-1β, IL-6, NF-κB, as well as the expression of mir-155 and mir-21 in the visceral adipose tissue (VAT) of rats with T2DM.

METHODS

For this experimental study, 32 male Wistar rats were induced with T2DM by a high-fat diet combined with a low-dose streptozotocin injection. The rats were randomly assigned to four groups: AT and Mg supplementation (AT + Mg), AT (5 days/week for 8 weeks), Mg supplementation (received daily supplementation of Mg chloride), and diabetic control (C). An 8-week AT program was implemented, with gradually increasing the intensity and duration to reach 25 m/min and 60 min in the 8th week, respectively. The training intensity was set at 50-60% of VO2max. The Mg groups were provided with rat diets containing 1000 mg/kg of Mg. The AT + Mg group received both interventions, while the C group served as the untreated control. Serum biomarkers were measured using enzyme-linked immunosorbent assay (ELISA), and VAT samples were collected for gene expression analysis using real-time polymerase chain reaction (PCR).

RESULTS

Serum biomarker analysis revealed that the AT + Mg group had a significant decrease in fasting insulin (p = 0.001) and serum glucose (p = 0.001), as well as an increase in adiponectin levels compared to the C group (p = 0.002). Additionally, the AT + Mg group showed a significant reduction in serum leptin, TNF-α, IL-6, IL-1β, and NF-κB, as well as downregulation of mir-155 and mir-21 in the VAT compared to the other groups. The AT group also showed improvements in several parameters, while the Mg group had fewer significant differences compared to the C group.

CONCLUSION

The combination of AT and Mg supplementation provides a synergistic effect that improves serum biomarkers and downregulates pro-inflammatory microRNAs in the VAT of T2DM rats. Meanwhile, Mg supplementation alone does not have a significant effect on pro-inflammatory microRNAs in the VAT. These findings suggest that such combined interventions could be a promising strategy for managing T2DM, potentially ameliorating inflammatory states and improving metabolic health.

The function of previously unappreciated exerkines secreted by muscle in regulation of neurodegenerative diseases

The initiation and progression of neurodegenerative diseases (NDs), distinguished by compromised nervous system integrity, profoundly disrupt the quality of life of patients, concurrently exerting a considerable strain on both the economy and the social healthcare infrastructure. Exercise has demonstrated its potential as both an effective preventive intervention and a rehabilitation approach among the emerging therapeutics targeting NDs. As the largest secretory organ, skeletal muscle possesses the capacity to secrete myokines, and these myokines can partially improve the prognosis of NDs by mediating the muscle-brain axis. Besides the well-studied exerkines, which are secreted by skeletal muscle during exercise that pivotally exert their beneficial function, the physiological function of novel exerkines, e.g., apelin, kynurenic acid (KYNA), and lactate have been underappreciated previously. Herein, this review discusses the roles of these novel exerkines and their mechanisms in regulating the progression and improvement of NDs, especially the significance of their functions in improving NDs' prognoses through exercise. Furthermore, several myokines with potential implications in ameliorating ND progression are proposed as the future direction for investigation. Elucidation of the function of exerkines secreted by skeletal muscle in the regulation of NDs advances the understanding of its pathogenesis and facilitates the development of therapeutics that intervene in these processes to cure NDs.

Impact of Paleo Diet on Body Composition, Carbohydrate and Fat Metabolism of Professional Handball Players

The Paleo diet (PD) involves a restriction of carbohydrates and increased fat content (35% energy from carbohydrates, 35% energy from fats and 30% energy from protein). The aim of this study was to examine the effect of the PD on body composition, concentration of carbohydrates and lipids, as well as insulin, irisin, adiponectin and leptin in the blood. A total of 25 handball players were assigned to two groups: 14 in the experimental group (PD) and 11 in the control group (CD), using a PD and a rational diet, respectively. Analysis of body mass and body composition (body mass index, fat mass, lean body mass, fat-free mass, muscle mass, bone mineral content and bone mineral density), as well as blood concentration of metabolism markers (glucose, insulin, total cholesterol, HDL-cholesterol, non-HDL-cholesterol, LDL-cholesterol, triglycerides, free fatty acids, β-hydroxybutyrate, irisin, adiponectin and leptin), were determined at the beginning and after 4 and 8 weeks of nutritional intervention. Body mass was lower (p < 0.01), and adiponectin blood concentration was higher (p = 0.03) in the PD group at the end of the intervention. There were no changes (p ≥ 0.05) in body composition and blood levels of other biochemical markers in either group.

Chronic food restriction in mice and increased systemic ghrelin induce preference for running wheel activity

OBJECTIVES

In eating disorders, particularly anorexia nervosa (AN), patients exhibit intense physical activity which is inappropriate regarding food restriction and chronic undernutrition, and exacerbates weight loss and energy deprivation. Rodent models of food restriction exhibit increased running wheel activity in the food anticipation period, also known as Food Anticipatory Activity (FAA). FAA probably has various physiological and/or neurobiological origins. Plasma concentrations of the orexigenic hormone ghrelin are, for example, increased during FAA. We hypothesize that the drive for physical activity in chronic food restriction is triggered by metabolic factors but also relies on motivational aspects that we aim to decipher in this study.

METHODS

Young female C57Bl6/J mice were exposed to a paradigm based on a progressive 50% quantitative food restriction alone (FR) or associated with running wheel activity (Food Restriction Wheel: FRW) in their home-cage during 15 days. We measured preference for running wheel in a three-chamber apparatus in which animals could choose to explore either a known running wheel or a novel object. Testing took place either during resting or during FAA. We calculated the time spent in each compartment and the activity in running wheels. After progressive refeeding over 10 days, mice were tested again when refed. Plasma levels of both ghrelin isoforms were measured with selective immunoassays.

RESULTS

When tested during FAA period, food restricted mice displayed increased preference for the running wheel compared to ad libitum fed controls. Both FR and FRW mice exhibited increased running time and distance in the wheel and running distance was correlated with ghrelin levels. Similar preference and behavior were found when testing took place during the resting period. Animals housed without an active wheel also exhibited active running. Progressive refeeding resulted in body weight restoration, a decrease in FAA and completely abolished preference for the running wheel. Refed animals displayed similar behavior as ad libitum fed controls.

CONCLUSIONS

These data provide evidence that food restriction-induced physical activity is closely correlated with metabolic adaptations to nutritional status implicating ghrelin in the quantity of physical activity.

Apelin as a Potential Regulator of Peak Athletic Performance

Apelin, as a cardiokine/myokine, is emerging as an important regulator of cardiac and skeletal muscle homeostasis. Loss of apelin signaling results in premature cardiac aging and sarcopenia. However, the contribution of apelin to peak athletic performance remains largely elusive. In this paper, we assessed the impact of maximal cardiorespiratory exercise testing on the plasma apelin levels of 58 male professional soccer players. Circulating apelin-13 and apelin-36, on average, increased transiently after a single bout of treadmill exercise; however, apelin responses (Δapelin = peak - baseline values) showed a striking interindividual variability. Baseline apelin-13 levels were inversely correlated with those of Δapelin-13 and Δapelin-36. Δapelin-13 showed a positive correlation with the maximal metabolic equivalent, relative maximal O₂ consumption, and peak circulatory power, whereas such an association in the case of Δapelin-36 could not be detected. In conclusion, we observed a pronounced individual-to-individual variation in exercise-induced changes in the plasma levels of apelin-13 and apelin-36. Since changes in plasma apelin-13 levels correlated with the indicators of physical performance, whole-body oxygen consumption and pumping capability of the heart, apelin, as a novel exerkine, may be a determinant of peak athletic performance.

A comparison of the associations between bone turnover markers and different sports fields: combat versus team sports

Sedentary life brings risks that include osteoporosis, while physical activity has many benefits for health in general and the skeletal system. Irisin is a hormone-like myokine regulated by mechanical force and it contributes to cortical and trabecular bone mineral density. This study aimed to investigate the effects of different types of sports on bone health by measuring elite athletes’ fibronectin type III domain 5 (FNDC5), N-terminal collagen type I extension propeptide (PINP), and C-terminal cross-linking telopeptide of type I collagen (CTXI) levels. Combat sports athletes, team sports athletes, and sedentary control subjects were enrolled. Serum levels of proteins were measured by ELISA. FNDC5 levels of elite athletes were higher compared to the sedentary controls (P=0.0014). The highest FNDC5 level was measured in wrestlers among all considered groups. The PINP levels of the athletes were also higher than those of the sedentary control group (P=0.1431). The highest PINP level was determined in boxers. The CTXI levels of the athletes were lower than those of the sedentary control (P<0.0001). The lowest CTXI level was seen in boxers. The FNDC5 and PINP levels of combat sports athletes were higher than those of team sports athletes (P=0.0134 and P=0.0262, respectively), while the CTXI levels of combat sports athletes were lower than those of team sports athletes (P<0.0001). Our results indicated that FNDC5, PINP, and CTXI levels are associated with physical activity. The effect of the exercises performed by athletes of specific sports on bone health has not been studied in much detail before. Combining different exercises for athletes of a particular sport may be more beneficial for bone health.

Does exercise during a ketogenic diet effectively alter appetite sensation, appetite-regulating hormones, and body composition?

Exercise and diet are two essential interventions in weight control. The purpose of this study was to compare the effectiveness of two exercise training types during a ketogenic diet (KD) on appetite sensation, appetite-regulating hormones, and body composition in overweight or obese man. Thirty-six men, overweight or with obesity, voluntarily participated in this study. The participants were randomly assigned into three groups, including KD (n = 12), aerobic training during KD (AT-KD) (n = 12), and resistance training during KD (RT-KD) (n = 12) groups. The participants followed a low-carbohydrate diet for 6 weeks. Exercise training programs consisted of three sessions per week over 6 weeks. Appetite sensation was analyzed using a visual analogue scale (VAS) in fasting and postprandial states. The Enzyme-Linked Immunosorbent Assay (ELISA) method analyzed appetite-regulating hormones, including spexin, leptin, and acylated ghrelin, in a fasting state. Body composition was measured using bioelectrical impedance analysis (BIA). Furthermore, the ketosis state was monitored by measuring urinary ketones weekly. The results indicated that in both AT-KD and RT-KD groups, spexin and acylated ghrelin increased while leptin decreased without any between-group differences. Hunger and prospective food consumption (PFC) declined while satiety and fullness increased in all groups. The AT-KD group experienced a significant decrease in hunger and PFC, while fullness increased compared with the KD group. Fat mass, weight, and body mass index (BMI) decreased in all groups. Lean body mass increased in the RT-KD group (+2.66 kg) compared with both AT-KD and KD groups (-1.71 and -1.33 kg, respectively). This study demonstrated that AT-KD and RT-KD effectively altered appetite-regulating hormones and suppressed appetite sensation. In addition, both interventions had a favorable effect on weight loss and body fat reduction, with a more pronounced effect of RT-KD on maintaining lean body mass in overweight or obese men.

The effects of different types of exercise on circulating irisin levels in healthy individuals and in people with overweight, metabolic syndrome and type 2 diabetes

Irisin is a myokine secreted during exercise. It has drawn the attention of researchers as it regulates several effects of exercise that are considered beneficial. It has also been proposed as a therapeutic tool to treat metabolic disorders. In recent years, the effect of different types of training on circulating irisin has been studied in large populations. An overall beneficial result has been shown, however, the outcome of the investigations has raised some controversy. Herein we evaluated the existing literature on the effects of different types of training on the circulating irisin levels in healthy subjects and in those displaying different metabolic condition. We conducted queries in the PubMed and Web of Science databases for literature published between January 2010 and January 2021. Thirty-seven original articles were retrieved and they were included in this review. Any letter to the editor, meta-analyses, reviews, and systematic review articles were excluded. From these 37 articles, 19 of them reported increased levels of circulating irisin. The interventions encompassed aerobic, resistance, combined, circuit, and interval training types. Such increase of circulating irisin was reported for healthy subjects and for those displaying different metabolic condition. A training that is steadily kept with a moderate to high intensity, including that characterized by brief highly intense intervals, were distinguishable from the rest. Nevertheless, the training effectiveness as evaluated by the increased circulating irisin levels depends on the subject’s metabolic condition and age.

Comparative Impact of Various Exercises on Circulating Irisin in Healthy Subjects: A Systematic Review and Network Meta-Analysis

Irisin is a myokine that is secreted from skeletal muscle during exercise and increases lipid metabolism, converting white adipose tissue to brown adipose tissue. Recent studies have shown conflicting results in relation to chronic and acute exercise and irisin. The aim of this study was to evaluate the effects of chronic and acute exercise training on circulating (plasma/serum) irisin level in healthy subjects. We conducted a search of Cochrane Library, PubMed, ISI, Scopus, Embase, and Pedro up to September 2021. A random effects network meta-analysis was performed to calculate the pooled estimate of standardized mean difference (SMD) for acute and chronic exercise effects on irisin level, using Hedge's g statistic. Of the 16 studies included, six were acute exercise studies (175 participants). The aerobic (Hedge's g = 0.23; 95% CI: -0.58, 1.03) and the anaerobic exercises (Hedge's g = 0.12; 95% CI: -0.45, 0.70) were associated with the increased level of irisin, compared to the control. In the ten chronic exercise studies (433 participants), the resistance training was superior to anaerobic and aerobic training (P score = 0.632). However, comparing acute and chronic exercise studies, acute training showed the most excellent potential as the best treatment to improve the irisin level (P score = 0.721). This network meta-analysis showed that acute aerobic exercise has a more effect on irisin levels than acute anaerobic exercise. Also, chronic resistance training has the greatest additive effect on irisin levels compared to chronic aerobic and anaerobic training.

Impact of Exercise and Aging on Mitochondrial Homeostasis in Skeletal Muscle: Roles of ROS and Epigenetics

Aging causes degenerative changes such as epigenetic changes and mitochondrial dysfunction in skeletal muscle. Exercise can upregulate muscle mitochondrial homeostasis and enhance antioxidant capacity and represents an effective treatment to prevent muscle aging. Epigenetic changes such as DNA methylation, histone posttranslational modifications, and microRNA expression are involved in the regulation of exercise-induced adaptive changes in muscle mitochondria. Reactive oxygen species (ROS) play an important role in signaling molecules in exercise-induced muscle mitochondrial health benefits, and strong evidence emphasizes that exercise-induced ROS can regulate gene expression via epigenetic mechanisms. The majority of mitochondrial proteins are imported into mitochondria from the cytosol, so mitochondrial homeostasis is regulated by nuclear epigenetic mechanisms. Exercise can reverse aging-induced changes in myokine expression by modulating epigenetic mechanisms. In this review, we provide an overview of the role of exercise-generated ROS in the regulation of mitochondrial homeostasis mediated by epigenetic mechanisms. In addition, the potential epigenetic mechanisms involved in exercise-induced myokine expression are reviewed.

The role of irisin in metabolic flexibility: beyond adipose tissue browning

Metabolic flexibility is the ability to adapt to physiological and environmental changes in metabolic demand. Irisin was originally discovered as an exercise-induced myokine involved in fat browning. In this review, we summarize emerging evidence for the role of irisin in regulating glucose metabolism and insulin sensitivity in skeletal muscle, neuroplasticity and satiety in central nervous system, β cell function and insulin secretion in the pancreas, bone remodeling, and adipose tissue function, which together orchestrate whole-body metabolic flexibility. Irisin is a key communicating mediator between skeletal muscle and other organs, and its manipulation could be a promising therapeutic strategy for treating obesity and related metabolic disorders. Teaser: This review summarizes recent progress in manipulating metabolic flexibility with irisin, and discusses its potential application as a drug target to treat obesity and related metabolic disorders.

An updated systematic review on the effects of aerobic exercise on human blood lipid profile

Sedentary lifestyle and dyslipidemia are well-recognized risk factors for cardiovascular diseases (CVD). Changes in blood lipid profile (total cholesterol (TC), triglycerides, high-density lipoprotein [HDL], and low-density lipoprotein [LDL]) due to the exercise may be beneficial for decreasing CVD-related events. In this review we aimed to investigate the effect of different types of exercise on lipid profile components in people with different health conditions and age ranges. A systematic search was performed covering PubMed, Web of Science, and Google Scholar for English articles from 2010 until November 2021. Finally, 31 studies were included in our study. Results showed that exercise in younger individuals sometimes resulted in no significant changes of any of the variables or some of them; however, efficient improvement was observed in all studies of older and middle-age groups. In terms of health condition and gender; healthy individuals, overweight people, subjects with type 2 diabetes and obesity, and male participants found to have benefited more from the exercise. In patients with chronic kidney diseases lipid profile improvement was not significant. The cardiac rehabilitation program, particularly comprehensive cardiac rehabilitation, proved to be more beneficial than exercise alone in the case of cardiovascular patients and those at elevated risk of CVD. In conclusion exercise is beneficial in terms of improving lipid profile but for younger population, and those with kidney problems and CVD patients, more further preparations are needed under the supervision of experts in the field of sports and medicine to achieve the desired result. Also, more studies are needed for these groups in order to provide a definite and reliable conclusion.

Progress of Adipokines in the Female Reproductive System: A Focus on Polycystic Ovary Syndrome

Adipose tissue, one type of loose connective tissue in the human body, maintains the primary task of energy storage. Adipose tissue is not only an energy reservoir but also plays a vital role as the largest endocrine organ of the whole body via releasing a variety of adipokines, which participate in many pathophysiological processes, such as energy metabolism regulation, glucose and lipid metabolism, and inflammation. Polycystic ovary syndrome (PCOS) is a disorder that mainly involves the female reproductive system, affecting women of childbearing age particularly. Insulin resistance (IR) and hyperandrogenemia (HA) have been implicated as a critical link involving the etiology and outcome of PCOS. A great deal of studies has bridged the gap between adipokines (such as Adiponectin, Chemerin, Metrnl, Apelin, Resistin, Visfatin, Leptin, Vaspin, Lipocalin 2, and Omentin) and reproductive fitness. In this review, we will focus on the adipokines' functions on PCOS and come up with some points of view on the basis of current research.

Long-Term Effect of Exercise on Irisin Blood Levels-Systematic Review and Meta-Analysis

Physical exercise may activate a number of important biochemical processes in the human body. The aim of this systematic review and meta-analysis was to identify the long-term effect of physical activity on irisin blood levels. We searched PubMed, Scopus, and Web of Science for articles addressing the long-term effect of physical exercise on irisin blood levels. Fifty-nine articles were included in the final qualitative and quantitative syntheses. A statistically significant within-group effect of exercise on irisin blood levels was in 33 studies; out of them, the irisin level increased 23× and decreased 10×. The significant positive between-groups effect was found 11×. Furthermore, the meta-analysis indicated that physical exercise had a significant positive effect on irisin blood levels (SMD = 0.39 (95% CI 0.27–0.52)). Nevertheless, considerably high heterogeneity was found in all the analyses. This systematic review and meta-analysis indicate that physical exercise might increase irisin blood levels; however, the results of individual studies were considerably inconsistent, which questions the methodological detection of irisin by ELISA kits.

Investigation of the effect of training on serotonin, melatonin and hematologic parameters in adolescent basketball players

OBJECTIVES

Exercise can improve both health and mood. Some beneficial effects of exercise are attributed to endocrine status. This study aims to evaluate the effect of eight weeks of basketball training on melatonin, serotonin, and hematologic parameters in basketball players.

METHODS

The experimental group was selected form 34 healthy young boys, aged between 13 and 16 years old. The participants were randomly assigned to the control group (n=17) and the exercise group (n=17). The exercise program consisted of 2 h/day aerobic activity of basketball training in 5 days a week for 8 weeks. Venous blood was taken on the day before experiment (pre-exercise) and on the day following the last exercise (post-exercise) and hormone levels were detected by ELISA.

RESULTS

Serotonin and melatonin levels significantly increased in the post-exercise group compared to the other groups (p<0.05). Exercise caused increase in WBC, RBC, HCT and Hb levels (p<0.05) while did not alter PLT, MCH, and PCT levels (p>0.05). This study indicates that an eight weeks-long regular aerobic exercise increased melatonin and serotonin levels, and also altered some hematological parameters.

CONCLUSIONS

In conclusion, it is believed that improvement in levels of serotonin, melatonin, and hematological parameters after eight weeks of regular basketball training in basketball players could be attributed to beneficial effects of exercise. Investigation in other branches of sports and in different gender and age groups would make contribution into exercise physiology and training science.

Crossing the Antarctica: Exploring the Effects of Appetite-Regulating Hormones and Indicators of Nutrition Status during a 93-Day Solo-Expedition

Future deep space astronauts must maintain adequate nutrition despite highly stressful, isolated, confined and dangerous environments. The present case-study investigated appetite regulating hormones, nutrition status, and physical and emotional stress in a space analog condition: an explorer conducting a 93-day unsupported solo crossing of Antarctica. Using the dried blood spot (DBS) method, the subject drew samples of his blood on a regular basis during the expedition. The DBSs were later analyzed for the appetite regulating hormones leptin and adiponectin. Energy intake and nutritional status were monitored by analysis of albumin and globulin (including their ratio). Interleukin-6 (IL-6) was also analyzed and used as an energy sensor. The results showed a marked reduction in levels of the appetite-reducing hormone, leptin, and the appetite stimulating hormone, adiponectin, during both extreme physical and psychological strain. Nutrition status showed a variation over the expedition, with below-normal levels during extreme psychological strain and levels abutting the lower bounds of the normal range during a phase dominated by extreme physical hardship. The IL-6 levels varied substantially, with levels above the normal range except during the recovery phase. It was concluded that a daily intake of 5058 to 5931 calories seemed to allow recovery of both appetite and nutritional status between extreme physical and psychological hardship during a long Arctic expedition. Furthermore, IL-6 may be a sensor in the muscle-liver, muscle-fat and muscle-brain crosstalk. These results may help guide nutrition planning for future astronaut crews, mountaineers and others involved in highly demanding missions.

The Role of Exercise, Diet, and Cytokines in Preventing Obesity and Improving Adipose Tissue

The prevalence of obesity continues to rise worldwide despite evidence-based public health recommendations. The promise to adopt a healthy lifestyle is increasingly important for tackling this global epidemic. Calorie restriction or regular exercise or a combination of the two is accepted as an effective strategy in preventing or treating obesity. Furthermore, the benefits conferred by regular exercise to overcome obesity are attributed not only to reduced adiposity or reduced levels of circulating lipids but also to the proteins, peptides, enzymes, and metabolites that are released from contracting skeletal muscle or other organs. The secretion of these molecules called cytokines in response to exercise induces browning of white adipose tissue by increasing the expression of brown adipocyte-specific genes within the white adipose tissue, suggesting that exercise-induced cytokines may play a significant role in preventing obesity. In this review, we present research-based evidence supporting the effects of exercise and various diet interventions on preventing obesity and adipose tissue health. We also discuss the interplay between adipose tissue and the cytokines secreted from skeletal muscle and other organs that are known to affect adipose tissue and metabolism.

Associations of circulating irisin with 24-h blood pressure, total and visceral fat, and metabolic parameters in young adult hypertensives

Objective

Some experimental and clinical studies suggest a possible role of irisin in central and peripheral regulation of blood pressure. The purpose of the study was to assess the associations between serum irisin levels, total and visceral fat, metabolic parameters, and blood pressure pattern during 24-h monitoring (ABPM).

Methods

In 206 patients with essential hypertension receiving standard antihypertensive treatments, we assessed anthropometric indices; serum irisin, blood lipids (total cholesterol, LDL-C, HDL-C, and triglycerides), glucose and insulin; body composition including lean mass and total, visceral, android and gynoid fat using a dual-energy x-ray absorptiometry; ABPM; and Homeostasis Model Assessment-Insulin Resistance (HOMA-IR).

Results

Baseline irisin levels were within normal reference ranges and comparable between the genders. There were no significant correlations of irisin with age, anthropometric variables, lipids, HOMA-IR, body composition, as well as 24-h blood pressure and dipping status. In univariate analysis, age, fat mass and distribution, lipids and glucose, HOMA-IR, and nocturnal blood pressure fall were poor predictors of irisin levels. These neutral associations were not affected by age, gender, and treatment modality.

Conclusion

In young adult hypertensives, serum concentration of irisin was within a normal range and not associated with total and regional fat, blood lipids, insulin resistance, as well as 24-h blood pressure and the magnitude of its nocturnal fall.

Concentrations of Circulating Irisin and Myostatin in Race and Endurace Purebred Arabian Horses-Preliminary Study

Simple Summary

Irisin and myostatin are regulatory proteins produced by muscle cells. The aim of the study was to evaluate the effect of exercise on plasma irisin and myostatin concentrations in horses in different types of training (speed versus endurance). To find out, we tested 20 Arabian horses, submitted to the two different equestrian disciplines, and consequently different training regimes. The first group of horses realized a short-term, high-speed bout of exercise whereas the second group of horses were submitted to long-lasting, endurance effort. The obtained results showed that the single bout of exercise induced an increase in plasma myostatin concentration. Plasma irisin level decreased during the race season in racehorses. This means that irisin and myostatin may play a regulatory role in the maintenance of the energy balance processes.

Abstract

Skeletal muscle is considered to be the largest endocrine organ determining the maintenance of energy homeostasis. Adaptive changes in skeletal muscles in response to physical exercise influence the production as well as secretion of myokines, which are bioactive factors that play a crucial role in energy expenditure processes. The aim of the study was to investigate the impact of two different types of exercise on the circulating level of two of these, myostatin and irisin, in trained horses. Twenty purebred Arabian horses were involved in the study: 10 three-year-old horses trained on the racetrack and 10 endurance horses aged 7.4 ± 1.9 years. The horses from both groups were regularly trained throughout the entire season, during which they also participated in Polish National competitions. To assess the influence of the training sessions on plasma myostatin and irisin concentrations, blood samples taken at rest and 30 min after the end of exercise were analyzed. In the studied horses, the single bout of exercise did not influence plasma irisin but induced an increase in plasma myostatin concentration. In racehorses, plasma irisin concentration decreased with the length of the training season. Plasma myostatin was higher in endurance horses than in three-year-old racehorses. Lack of exercise-induced fluctuation in circulating irisin in studied horses suggests that myostatin released in response to exercise provides a negative feedback signal to irisin release.

Unexpected Association of Desacyl-Ghrelin with Physical Activity and Chronic Food Restriction: A Translational Study on Anorexia Nervosa

Anorexia nervosa (AN) is a severe metabopsychiatric disorder characterised by caloric intake restriction and often excessive physical exercise. Our aim is to assess in female AN patients and in a rodent model, the co-evolution of physical activity and potential dysregulation of acyl—(AG) and desacyl—(DAG) ghrelin plasma concentrations during denutrition and weight recovery. AN inpatients were evaluated at inclusion (T0, n = 29), half—(T1) and total (T2) weight recovery, and one month after discharge (T3, n = 13). C57/Bl6 mice with access to a running wheel, were fed ad libitum or submitted to short—(15 days) or long—(50 days) term quantitative food restriction, followed by refeeding (20 days). In AN patients, AG and DAG rapidly decreased during weight recovery (T0 to T2), AG increased significantly one-month post discharge (T3), but only DAG plasma concentrations at T3 correlated negatively with BMI and positively with physical activity. In mice, AG and DAG both increased during short- and long-term food restriction. After 20 days of ad libitum feeding, DAG was associated to persistence of exercise alteration. The positive association of DAG with physical activity during caloric restriction and after weight recovery questions its role in the adaptation mechanisms to energy deprivation that need to be considered in recovery process in AN.