Possible cross-talk between fat tissue and immune system in COVID-19 with considering to the physical exercise

Dear Editor-in-ChiefCoronaviruses are a very large family of viruses that are phenotypically and genetically diverse and are common in humans and animals. The Prevalence of Coronavirus disease 2019 (COVID-19) began in Wuhan, China. As of 17 March 2020, extensive human-to-human transmission mainly occurs via the respiratory particles of the infected person.  Among COVID-19 cases, it seems that new pandemic complications are already well-defined in obese and overweight people with body mass indexes (BMI) over 25 kg/m2 or even higher that contribute to increased risk of SARS-CoV-2 infection. The higher BMI in COVID-19 patients, the higher risk of medical complications, hospitalization in the intensive care unit (ICU), and invasive mechanical ventilation (IMV) (Földi et al., 2020). However, BMI does not show the distribution of body fat, and therefore research results cannot show the effect of excess fat in different parts of the body on the severity of COVID-19. In confirmation of this finding, it can be said that although the ratio of total body fat in women is higher than men on average, the incidence of COVID-19 is higher in men (Simonnet et al., 2020).The possible critical mechanism by which adipose tissue accumulation increases the risk of COVID-19 in patients is unknown. However, fatty tissue may serve as a reservoir for viral production that might contribute to the increased risk from COVID-19 for patients with obesity. It is suggested that fatty tissue is targeted by SARS-CoV-2. The mechanism by which SARS-CoV-2 enters cells is not fully elucidated. But apart from a direct fusion of the virus with the plasma membrane, it appears that various types of endocytosis might be involved in this process. These lipid membrane trafficking events include clathrin-mediated endocytosis, caveolin- mediated involved in muscle hypertrophy and strength. In this regard, OCN-deficient mice have been shown to have lower muscle mass; inversely, improved muscle mass was found in older mice with ucOCN administrations. Recent data has figured out a novel mechanism of bone-muscle crosstalk in relation to OCN and IL6 signaling (Kirk et al., 2020).Endocytosis, macropinocytosis, and phagocytosis. Caveolin-mediated endocytosis is especially interesting to study as caveolae are abundant in fat cells, caveolins participate in fatty tissue function because caveolin was shown to interact with various viral proteins. In addition, the increased number of fat cells would increase the pool of infection susceptible cells. Fatty tissue contains not only fat cells but cells of stromal vascular fraction among which adipocyte precursors and macrophages. These cells also express ACE2 and display a potential target of SARS-Cov-2 infection and thus may contribute to increased inflammatory status (Dugail, Amri, & Vitale, 2020). Another possibility is that fatty tissue droplets could provide a platform for virus replication and production. Concerning the hypothesis that fatty tissue is an infection place for the SARS-CoV-2 virus, it has not yet been established if viral loads are proportional to fatty tissue mass in patients. The ACE2 activity leading to increased levels of angiotensin II and so increased inflammation and lung damage. It seems that fat cells play a substantial role in viral infection and the viral life cycle. Adipose tissue is directly involved in contact with the viral membrane of the host cell. For example, fats are critical to the formation and function of the viral replication complex and can provide some of the energy required for viral replication. In addition, specific fats are needed for the formation of double-membrane vesicles for viral genome amplification and the production of viral particles. Viral internalization can occur with endocytosis and viral release from cells. It is possible that fat availability and fats metabolism modifications occurring in an obese patient also contribute to improving several stages of the virus's life cycle and severity of the disease (Dugail et al., 2020).In this regard, any approach should consider reducing the costs of intensive care units to reduce the mortality of patients. Especially with concerning increase their number and people at higher risk in obese people. Moderate-intensity exercise can directly boost the immune system, antioxidant defenses, and anti-inflammatory responses Adipose tissue molecular adaptation always was considered as one of the mechanisms for the anti-inflammatory effects of physical exercise. Aerobic exercise is a physical activity that is moderate-intensity and does not put much pressure on the body. Regular exercise has been shown to improve infection, antibacterial and antiviral immunity, reduce inflammation, and delay immune aging (Campbell & Turner, 2018). Following the moderate-intensity physical activity, an increase in the number of neutrophils and natural killer (NK) cells is detected, and salivary IgA concentrations increase (Brolinson & Elliott, 2007). During physical exercise, rapid and general mobilization of NK cells into the bloodstream is induced by adrenergic B signaling and catecholamines. It is suggested that mobilized NK cells are affected by muscle-derived myokines, exercise-related hyperthermia, and coronary arteries, which are affected by regulation, redistribution, and activation of mobilized NK cells (Brolinson & Elliott, 2007). Moreover, adipocytes play a critical role in NK cell activations. Adipose tissue may respond to the activation of NK cells during exercise in a cross-talk with the immune system.Moderate exercise was exercise is one of the mechanisms in NK cell activation following physical exercise.  The results show a 20 to 30 percent reduction in upper respiratory tract infections in people who do moderate-intensity of physical activity in their daily lives (Brolinson & Elliott, 2007). Therefore, it can be said that moderate-intensity training can be an effective way to boosting the immune system. Possible cross-talk between fat and immune tissues was approved in some other studies. It is suggested that some exercise factors such as IL-6 and Hsp70 can be effective in the possible cross-talk between the immune system and fat tissue. Molecular and structural changes in adipose tissue following physical exercise can be effective in improving immune responses.Fatty tissue is probably targeted by the SARS-CoV-2 virus, which causes adipose tissue dysfunction. Accumulation of fat tissue also serves as a platform for replication and production of virus. Based on the evidence, it seems that exercise activities, especially combined exercise training, reduce fat mass in obese or overweight people, reduce the risk of COVID-19, as well as the risk of severity and side effects in patients. Possible cross-talks between the immune system and adipose tissue could be one of the possible mechanisms in boosting immune responses against the virus

Exercise training in polluted environment: A narrative review with focus on combat physical fitness

Air pollution is one of the most important problems of recent decades, which has serious toxic effects on human health and the environment. Sources of pollution vary from small units of cigarettes and natural sources such as volcanic activity to large volumes of emissions from car engines and industrial activities or even radioactive ones. Today, there are various pollutants around the world that negatively affect human health. Walking and being in a polluted environment can increase the penetration of pollutants such as lead in the body. Increasing physical activity such as long-term running, which is widely used in some jobs such as military jobs, can increase the activity of muscle tissue, and as a result, the cardiovascular system becomes more active and helps absorb more pollutants. Lead acetate is a possible carcinogen in humans, which is absorbed into the human body by pollutants. There is evidence that lead compounds can cause lung, brain, stomach, and kidney cancer in humans. However, pollution does not include air pollution only, and noise pollution can endanger human health as well. Since some occupations such as those of military experience various types of noise, as well as chemical and radioactive pollution and the point that having high physical fitness is essential for these people, this study examined the impact of various pollutants on the military personnel and also sought to see whether exercising and having high physical fitness of military personnel can reduce the stress caused by the pollution

INFLUENCE OF MUSIC TYPE LISTENING ON ANAEROBIC PERFORMANCE AND SALIVARY CORTISOL IN MALES ATHLETES

Music has been widely recommended as a technique to enhance the psychophysical state of participants in sport and exercise. However, there is scant scientific evidence to clarify its proposed benefits. Therefore, the aim of this study was to determine the effect of fast and slow rhythm of music on anaerobic performance and salivary cortisol concentration in trained men. Thirty male physical education college students (ages: 25.66±3.89 yr, height: 176.65 ± 7.66 cm, body mass: 78.45±16.20 kg) voluntary participated in this study and divided to three groups: fast music, slow music, and no music(control). All subjects performed the coninghum test following a 20% grate and 14.3km/h speed on the treadmill. For measuring of cortisol, not stimulated samples of saliva collected, 15 minutes befor and immediately 5 and 30 minute after the exercise. No significant differences were found in anaerobic performance among the three groups in pretest indicating homogeneity of the groups. However, salivary cortisol no significant in anaerobic performance 5 and 30 minute after exercise as well. Summarily, Music doed not have a positive effect on performance, this study provided some support for the hypothesis that listening fast and slow music not significantly impacted during supramaximal exercise

Adjuvant effect of an acute moderate endurance exercise in herpes simplex virus 1 vaccination and its boosters on interleukin 10 cytokine and granzyme B in mice

Background: The herpes simplex viruses cause a variety of clinical illnesses that are painful and often distressing. To control the infection, the development of an effective vaccine that prevents or reduces the primary and recurrent infections would be of great significance. With considering to immunological changes following an acute endurance exercise, the purpose of this study was to assess adjuvant effects of an acute endurance exercise in first herpes simplex virus 1 vaccine injection and its booster shots on interleukin-10 cytokine and granzyme B levels. Methods: This experimental study was carried out in Tarbiat Modares University during May to October 2016. 32 BALB/c mice were divided into 4 groups: control, vaccine, vaccine plus an acute exercise in first injection and vaccine plus an acute endurance exercise in first injection and booster shots. Mice without or with access to acute endurance exercise were immunized intramuscularly with inactivated KOS strain of HSV-1. Two weeks after three booster shots of vaccine, interleukin-10 and granzyme B levels were determined in spleen cell culture with enzyme-linked immunosorbent assay (ELISA) method. Results: This study was undertaken to test the hypothesis that an acute endurance exercise as an adjuvant in herpes simplex virus 1 vaccine can change interleukin-10 cytokine and granzyme B levels in mouse model. The result of this study showed significant differences between groups in interleukin-10 and granzyme B levels (P=0.001). Increasing in granzyme B levels with concurrent decreases in interleukin-10 levels was observed following using vaccine plus acute exercise in first injection of vaccine and booster shots. Conclusion: It is suggested that exercise may stimulate parameters related to cellular immunity and hence decrease the risk of infection decreased levels of interleukin-10 in experimental group that had vaccine plus acute exercise in the first injection of vaccine and booster shots as an adjuvant was observed. These results demonstrate alternation of T helper 2 cells function and improve of cell immunity for protection against herpes simplex virus 1 infections

Investigating The Effect of Aerobic Interval Training with Selenium Nanoparticles on the Content of IL-6, TNF-α and IL-4 cytokines in spleen tissue of Mice with Breast Cancer

Background & Objective: Cytokines are molecules that are related to immunologic responses. Considering the antioxidant and immunologic effects of selenium nanoparticles and aerobic exercise training, the aim of this study was to examine the effects of aerobic exercise training and supplementation with selenium nanoparticles on protein content of Interleukin-4, Interleukin-6 and tumor necrosis factor Alpha in spleen tissue in mice with breast cancer. Material and Methods: 64 Balb/c mice were randomly divided into 8 groups including Control-Health, Control-Tumor, Training-Healthy, Training-Tumor, Selenium nanoparticles-Health, Selenium nanoparticles-Tumor, Selenium nanoparticles-Training-Health and Selenium nanoparticles–Training-Tumor. Animals in different groups passed 6 weeks aerobic interval training and supplementation with selenium nanoparticles before and after cancer induction. At the end of the sixth week, cytokines protein levels in spleen tissue were measured by ELISA method. Results: Based on the current study results exercise training and selenium nanoparticles caused significant decrease in tumor volume (P<0.05). Also, results showed that cancer induced a significant decrease in cytokines levels in tumor tissue (P<0.05). But concurrent using selenium nanoparticles and aerobic interval training induced increase in tumor necrosis factor Alpha levels in spleen tissue (P<0.05). Conclusion: It seems that aerobic exercise training and selenium nanoparticles supplementation could have an effective role in the activation of immune system and decreasing in tumor volume, with increasing in tumor necrosis factor Alpha as a T helper 1 cytokine

Effects of physical rehabilitation intervention in COVID-19 patients following discharge from hospital: A systematic review

Background Hospitalized patients recovering from coronavirus disease 2019 (COVID-19) may experience disability and suffer from significant physical and mental impairment requiring physical rehabilitation following their discharge. However, to date, no attempt has been made to collate and synthesize literature in this area. Objective This systematic review examines the outcomes of different physical rehabilitation interventions tested in COVID-19 patients who were discharged from hospital. Search strategy A systematic search of MEDLINE/PubMed, CINAHL, Scopus and medRxiv was conducted to identify articles published up to March 2022. Inclusion criteria This systematic review included studies of outpatient rehabilitation programs for people recovering from COVID-19 who received physical activity, exercise, or breathing training to enhance or restore functional capacity, pulmonary function, quality of life, and mental health or function. Data extraction and analysis Selection of included articles, data extraction, and methodological quality assessments were conducted by two review authors respectively, and consensus was reached through discussion and consultation with a third reviewer. Finally, we review the outcomes of studies based on four categories including: (1) functional capacity, (2) pulmonary function, (3) quality of life, and (4) mental health status. Results A total of 7534 titles and abstracts were screened; 10 cohort studies, 4 randomized controlled trials and 13 other prospective studies involving 1583 patients were included in our review. Early physical rehabilitation interventions applied in COVID-19 patients who were discharged from the hospital improved multiple parameters related to functional capacity, pulmonary function, quality of life and mental health status. Conclusion Physical rehabilitation interventions may be safe, feasible and effective in COVID-19 patients discharged from the hospital, and can improve a variety of clinically relevant outcomes. Further studies are warranted to determine the underlying mechanisms

Exercise-induced modulation of monocytes in breast cancer survivors

Background: Exercise training reduces inflammation in breast cancer survivors; however, the mechanism is not fully understood. Objectives: The effects of acute and chronic exercise on monocyte toll-like receptor (TLR2 and 4) expression and intracellular cytokine production were examined in sedentary breast cancer survivors. Methods: Eleven women with stage I, II, or III breast cancer within one year of treatment completion performed an acute, intermittent aerobic exercise trial. Blood samples were obtained before, immediately, and 1 h after a 45-min acute exercise trial that was performed before and after 16 weeks of combined aerobic and resistance. LPS-stimulated intracellular IL-1ß, TNF, and IL-6 production, and TLR2 and TLR4 expression were evaluated in CD14+CD16- and CD14+CD16+ monocytes using flow cytometry. Results: Exercise training decreased IL-1ß+CD14+CD16- proportion (24.6%, p=0.016), IL-1ß+CD14+CD16- mean fluorescence intensity (MFI) (−9989, p=0.014), IL-1ß+CD14+CD16+ MFI (−11101, p=0.02), and IL-6+CD14+CD16- proportion (16.9%, P=0.04). TLR2 and TLR4 expression did not change following exercise training but decreased 1 h after acute exercise in CD14+CD16- (−63, p=0.002) and CD14+CD16+ (−18, p=0.006) monocytes, respectively. Immediately after the acute exercise, both monocyte subgroup cell concentration increased, with CD14+CD16+ concentrations being decreased at 1 h post without changes in intracellular cytokine production. Conclusions: Exercise training reduced monocyte intracellular pro-inflammatory cytokine production, especially IL-1ß, although these markers did not change acutely. While acute exercise downregulated the expression of TLR2 and TLR4 on monocytes, this was not sustained over the course of training. These results suggest that the anti-inflammatory effect of combined aerobic and resistance exercise training in breast cancer survivors may be, in part, due to reducing resting monocyte pro-inflammatory cytokine production