Journal of Exercise & Organ Cross Talk

Abstract Performing aerobic exercise in different disease conditions can regulate cardiac homeostasis and reduce cardiac apoptosis caused by the disease. In brain cancer, other tissues, including cardiac tissue, can also be affected. Since exercise training causes organ crosstalk, in this study, the effects of aerobic exercise training (AET) on cardiac apoptosis in Glioblastoma multiforme (GBM) rats are evaluated. Twenty-four male Wistar rats were divided into 3 groups (n=8 in each) of healthy control, GBM, and GBM+AET. Glioblastoma was injected into the frontal cortex of rats. The training group (AET) performed aerobic exercises on the treadmill for 4 weeks, 3 days a week at a speed of 18 meters per minute, for 25-40 minutes. In the end, the rats were sacrificed and caspase-3 and caspase-7 were analyzed from the myocardium by Real-time PCR method. Considering H&E image, the GBM group showed necrosis and apoptosis in cardiac tissue compared to the healthy group. Compared to the healthy control group, GBM significantly increased caspase-3 and caspase-7 mRNA in the myocardium (p<0.05). However, in contrast to the GBM group, the GBM+AET showed a significant decrease in caspase-3 and caspase-7 mRNA at the myocardium (p<0.05). Since tumor formation in the body can affect other distant tissues in an endocrine manner, it is suggested to prioritize aerobic exercise to control the damage caused by GBM on heart tissue. However, more studies are needed, especially on human samples.

Abstract Green tea polyphenols have been suggested to exert anti-inflammatory actions in in vivo and in vitro studies. The aim of this study was to investigate the effect of green tea extract (GTE) supplementation on pro-inflammatory cytokines during a single bout of resistance exercise (RE) in obese men. Participants were ten obese men who participated in a randomized, double-blind, placebo-controlled (PL) crossover study, administered 14-day GTE (500 mg/day) supplementation and PL with a 14-day washout period. After the supplementation periods, the participants performed the RE protocol, consisting of three sets of six exercises, to failure at 75% of one repetition maximum (1RM) and 2 min rest between sets. The serum samples were collected pre- and post-RE and analyzed for TNF-α, IL-1α, and IFN-γ. RE significantly increased TNF-α and IL-1α in obese men by 15% (p=0.043) and 18.71% (p=0.003) above the pre-RE values in the PL condition, respectively. However, GTE supplementation inhibited acute RE-induced increases in the TNF-α and IL-1α levels in obese men. Moreover, changes in the IFN-γ level during RE tended to be lower in GTE compared to the PL condition. Based on the findings, it can be concluded that 14-day GTE supplementation offers protection against RE-induced increases in pro-inflammatory cytokines in obese men. These immunomodulatory effects of GTE may be, in part, due to the anti-inflammatory properties of GTE in obese men that can be considered as a potential therapeutic factor to ameliorate obesity-associated inflammation.

Abstract The effectiveness of EMS on muscle and physical performance has been demonstrated in various populations, including healthy young adults. The aim of this study was to investigate the effect of an electrical muscle stimulation (EMS) session on changes in endostatin and vascular endothelial growth factor in inactive men. In this quasi-experimental research, 16 inactive healthy men (age, 20-30 years; BMI, 18 - 24.9 kg/m2) from Tehran were selected and randomly assigned to two EMS stimulation (n=8) and control (n=8) groups. The subjects performed the exercise (squat, lunge, crunch and plank) with WB-EMS clothes for 20 minutes; frequency 80 Hz, pulse 5 seconds and pulse pause 3 seconds. The levels of VEGF and endostatin in plasma were measured using kit and ELISA method. The data were analyzed using independent and correlated t-test at the P<0.05. The results showed that intragroup changes of endostatin and VEGF were significant after an EMS training session (P≤0.05), but not significant change was observed in the control group (P≥0.05). Also, the inter-group changes of endostatin showed no significant differences between the two groups in the post-test (P=0.1). However, the intergroup changes of VEGF indicated significant difference between the two groups in the post-test (P=0.001). It seems that in inactive people, EMS stimulation increases vascular endothelial growth factor as the most important positive regulator of the angiogenesis process and decreases endostatin as one of the most important negative regulators of the angiogenesis process.

Abstract Inflammation is a major component of almost all acute and chronic liver disorders, including non-alcoholic fatty liver disease. This study aimed to investigate the effect of high-intensity interval training on IL-22 and STAT3 gene expression of liver tissue in steatosis animal model. In this experimental study, 32 rats (weighing 200-250 gr) were selected and randomly divided into 4 groups including healthy control, fatty liver, HIIT and fatty liver + HIIT group. Rats were infected with fatty liver by oral tetracycline at a dose of 140 mg/kg (soluble in 2 ml of water) for 7 days. The HIIT exercise program performed on treadmill five sessions per week for 5 weeks. The IL-22 and STAT3 gene expressions in the liver tissue of samples were measured by Real Time PCR. Data were analyzed by One-way ANOVA and Tukey post hoc tests at significance level P <0.05. The results showed that the gene expression of IL-22 in liver tissue in HIIT group and fatty liver + HIIT was significantly lower than that in the fatty liver group (P = 0.001). Also, the gene expression of STAT3 in liver tissue in HIIT group and fatty liver + HIIT was significantly higher than that in the fatty liver group (P = 0.001). According to the results, the HIIT training program seems to help improve the liver steatosis.

Abstract The immune system is one of the main defenders of human health. The immune system can fight off viruses in the body and kill them. Therefore, keeping the components of the immune system healthy is very important. With age, the immune system ages, and its function decreases. This decline in immune function can easily lead to viral infections in the elderly. Evidence is accumulated that the best solution to maintain and enhance the immune system in the elderly is physical activity. Regular physical activity can lead to healthy aging of the immune system. Therefore, in this review study, we have discussed the changes in the immune system during aging and physical activity suggestions for healthy aging of the immune system. Finally, future research needs are reported.

Abstract Brain-derived neurotrophic factor (BDNF) plays a vital role in the brain. On the other hand, researchers showed that exercise may cause more release of BDNF and thus have a positive effect on the brain. Studies have reported controversial findings in multiple sclerosis, and there are no broad conclusions on this topic. This study aims to systematically investigate the effect of exercise training on BDNF concentration in multiple sclerosis animal models. Searches were conducted in the electronic databases of PubMed, Scopus, Medline, Cochrane Library and Google Scholar search engine to obtain the related articles about the role of exercise training on BDNF levels just in animal models of multiple sclerosis. All of the database searches were limited to the period from inception to February 2021. Two reviewers extracted study details and data. The methodological quality of the studies that used animal models was assessed using the PEDro Scale. Fourteen articles were included in this review with scores from 7/10 to 8/10 according to the PEDro scale. Five articles reported elevation, one article reported a reduction; and eight articles reported no changes in BDNF level following or preconditioning exercise training in model of multiple sclerosis. The findings of this study showed that aerobic exercise increases changes in central BDNF concentration in multiple sclerosis in animal model.

Abstract Dear Editor-in-Chief
 
Performing intense exercise on the body's organs is associated with various risks. At the same time, it is necessary for athletes to be aware of the dangers of intense exercise, for this purpose, studies have shown that the health of the oral cavity helps improve the performance of athletes (Gallagher et al., 2020). On the other hand, the disorder in the oral cavity with intense exercise significantly impacts the quality of life of athletes.
One of the most common diseases of oral cavity diseases caused by exercise is dental caries (D’Ercole et al., 2016). Dental caries is a chronic disease among humans and is one of the most common oral diseases worldwide. It is an important oral and dental disease that prevents achieving and maintaining oral health in all age groups. Dental caries refers to the local destruction of sensitive dental hard tissues by acidic by-products resulting from the bacterial fermentation of carbohydrates food. This disease is caused by an ecological imbalance between dental minerals and oral biofilms (plaque) (Selwitz et al., 2007; Thean et al., 2007; Yadav et al., 2017).
According to statistics announced by international organizations related to dentistry, approximately 2.43 billion people (about 36% of the population) around the world have dental caries in their permanent teeth and it affects about 620 million people or 9% of the population in milk teeth (Yadav et al., 2017). The statistics of athletes suffering from dental caries show that oral and dental cavity disorders among athletes were first recognized during the 1958 World Cup in Sweden. So that one dentist performed 118 tooth extraction surgeries on 33 athletes from different countries (Soares et al., 2014). Dental caries has also been reported among athletes in Olympic competitions. However, in the 2004 Athens Olympics, the visit of athletes by dentists took the second place among the visits of athletes to different departments of the clinic. In the 2008 Beijing Olympics, 1.600 people visited the dental department of the clinic at the venue of the competition. Similarly, in the 2012 London Olympics, 55% of the athletes were suffering from tooth decay (Needleman et al., 2013; Vougiouklakis et al., 2008; Yang et al., 2011). Azeredo et al. (2020), in a review article, investigated the prevalence of dental caries in athletes. The findings showed that the prevalence of dental caries among athletes is 46.25% (Azeredo et al., 2020). Larson et al. (2015), in a study, evaluated the intervention of exercise and energy drink consumption with health risk behaviors among adults. Findings suggest that health care providers should differentiate energy drink consumption and exercise from other unhealthy behaviors when designing programs for adults (Larson et al., 2015).
Research conducted in the field of exercise shows that exercise plays a role in reducing PH and increasing blood CO2. On the other hand, the decrease in the PH of saliva is related to the level of Co2 in the blood and the level of Co2 in the blood increases after exercise, and as a result, a high concentration of Co2 in the blood is transferred to the oral saliva, which is effective in reducing the PHof the saliva. In the same context, when the PH of saliva drops below the value of 5.5 that is assumed as the “Critical PH”, hydroxyapatite crystals in enamel begin to dissolve and decalcified areas occur (Ceyhan et al., 2020; Farsi, 2008; Milosevic et al., 1997; Okada et al., 2012). Borchers et al. (2022), analyzed saliva in their study to monitor intense exercise among male ultra-marathon runners. In this study, 9 healthy men who finished the distance of 160 km were selected as the statistical population of the research. The salivary markers were compared with blood markers following acute exercise stress in ultra-marathon runners at three baselines, shortly after the ultramarathon competition and after recovery. The findings showed that different blood markers and salivary cortisol had significant changes after the ultra-marathon running (Borchers et al., 2022).
Thus, it is recommended that athletes should be aware of the biochemical variables and other factors leading to dental caries and observe the oral and dental hygiene requirements. Moreover, due to the fact that athletes of various sports are affected by oral cavity diseases, it is necessary that athletes of competitive sports such as football, swimming, track and field, etc., pay more attention to the health of their oral cavity.
 

Abstract Dear Editor-in-Chief
The brain weighs about 1.36 kg and is mainly composed of blood. Although the brain includes only 2% of the body's weight, it receives 25% of the whole body oxygen consumption, 15% of the cardiac output volume and 2000 L of blood flow per day (Hartmann et al., 1994; Ohta et al., 1992; Xing et al., 2017). The brain has largest and most complex structure of the central nervous system. This organ regulates the functions of human body and stands for the basis of higher neural activities such as consciousness, alertness, learning, memory, intelligence, spirit and language learning. Cognitive function in a person means the brain ability to process, store, and extract information. In addition, this ability is a kind of advanced psychological function such as thinking, memory, and attention. Cognitive function plays an irreplaceable role in our daily life and study. Based on Cognitive psychology, the brain can modify its structure and function according to environmental changes and the experience of different types of exercising, especially exercise training, plays a crucial role in the evolution of the brain (Barnes. 2015; Raichlen et al., 2017). For example, exercise can positively affect synaptic plasticity and synaptic function to promote cerebral cortex, neural network and hippocampus function (an important structure in the memory information processing) (Ding et al., 2006; Li et al., 2019; Loprinzi et al., 2017). Exercise also has a significant effect on brain metabolism. Exercise not only promotes physical health of people, but also prevents mental illness and delays cognitive aging (Robinson et al., 2018).
Brain function depends on nerve fibers, number of neurons and synapses.  The cognitive performance is also closely related to the number of nerve fibers and synaptic connections, which can be reduced by diseases and aging process. The neurotrophics factors, such as neurotrophic factor (NGF) and brain-derived neurotrophic factor (BDNF) are required to provide nutrients to maintain the structure and function of nerve fibers and synaptic connections (Ivanov, 2014). However, with aging, sharp decrease of dendritic branches, degeneration of glial cells, the reduction of neuron number and contraction of nerves may impede the transmission of electrical signals in the nervous system, leading to the shrinkage of gray matter in the brain and cognitive impairment (Reisberg et al., 2008; Thorin-Trescases et al., 2018).
Several studies have shown that an active lifestyle could delay the aging of cognitive-control areas in the brain, and exercise can significantly improve brain health in patients with Alzheimer's disease and schizophrenia (Falkai et al., 2017; Frederiksen et al., 2018). Colcombe et al. (2003; 2006) used high-resolution magnetic resonance imaging (MRI) to scan the brain of 55 healthy people aged from 55 to 79 years old and observed a decrease in tissue density in the frontal and temporal lobes with age. The important point is that brain structure atrophy was related to aerobic fitness. In another study, 59 healthy people aged from 60-79 years old were divided into exercise training groups and control group. In the exercise training group, aerobic exercise intervention was conducted for 6 months. The results showed that the volume of gray matter and white matter was significantly increased in the exercise training group, and the researchers concluded that aerobic training could effectively delay brain aging process and lead to promote brain health (Colcombe et al., 2003; Colcombe et al., 2006; Colcombe & Kramer, 2003).
In terms of the mechanism based on which exercise training may enhance cognitive ability and  delay brain aging, it has been proved that exercise training can induce fibronectin type III domain-containing protein 5 (FNDC5) expression in skeletal muscle which will be released into the circulation with Irisin variant (Wrann et al., 2013). Spiegelman found that exercise training for 30 days in mice increased the activity of peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α), which is a metabolic regulatory molecule in skeletal muscle. PGC-1α could stimulate the upregulation of FNDC5 expression, and when FNDC5 enters the hippocampus through the blood-brain barrier, it enhanced the expression of BDNF in the dentate nucleus of the hippocampus (responsible for learning and memory). Interestingly, the study on sedentary mice injected with FNDC5 produced by exercise showed it activated gene for the brain health and improved the growth of new neurons involved in learning and memory. This new discovery links FNDC5, PGC-1α and BDNF in the cross talk between the brain and skeletal muscle upon exercise (Wrann et al., 2013). In addition to PGC-1 α/FNDC5 signaling on other molecules have also been found to affect BDNF expression in cognitive impairment.
In a cell model simulating the effect of exercise by adding AMPK agonist to L6 myoblasts rat, proteomics and mass spectrometry were performed to screen the factors secreted by myoblasts. Data showed that Cathepsin B (CTSB) increased after treatment while other cytokines did not changed. Meanwhile, CTSB levels also increased in gastrocnemius muscle and plasma of rats after voluntary wheel running exercise, anti-fatigue ability; spatial memory ability and coordinated movement improved in the exercised rats compared to the sedentary control group. However, these beneficial effects were absent in CTSB knockout rat. In addition, intravenous injected CSTB is able to enter the brain through blood-brain barrier and upregulate DCX and BDNF expression and thus enhancing hippocampal nerve growth (Moon et al., 2016).
Aerobic Training not only promotes physical health of people, but also prevents mental illness and effectively delays brain aging process, prevents brain structure atrophy, promotes volume gray and white matter and  promotes cognitive ability in patients with Age-induced cognitive impairment. Therefore, it is very important to conduct original and cross-sectional research in order to discover relevant and new mechanisms.