Alterations in the mucosal immune system by a chronic exhausting exercise in Wistar rats

Revitalizing the Gut Microbiome in Chronic Kidney Disease: A Comprehensive Exploration of the Therapeutic Potential of Physical Activity

Both physical inactivity and disruptions in the gut microbiome appear to be prevalent in patients with chronic kidney disease (CKD). Engaging in physical activity could present a novel nonpharmacological strategy for enhancing the gut microbiome and mitigating the adverse effects associated with microbial dysbiosis in individuals with CKD. This narrative review explores the underlying mechanisms through which physical activity may favorably modulate microbial health, either through direct impact on the gut or through interorgan crosstalk. Also, the development of microbial dysbiosis and its interplay with physical inactivity in patients with CKD are discussed. Mechanisms and interventions through which physical activity may restore gut homeostasis in individuals with CKD are explored.

Accelerometer-based physical activity is associated with the gut microbiota in 8416 individuals in SCAPIS

BACKGROUND

Previous population-based studies investigating the relationship between physical activity and the gut microbiota have relied on self-reported activity, prone to reporting bias. Here, we investigated the associations of accelerometer-based sedentary (SED), moderate-intensity (MPA), and vigorous-intensity (VPA) physical activity with the gut microbiota using cross-sectional data from the Swedish CArdioPulmonary bioImage Study.

METHODS

In 8416 participants aged 50-65, time in SED, MPA, and VPA were estimated with hip-worn accelerometer. Gut microbiota was profiled using shotgun metagenomics of faecal samples. We applied multivariable regression models, adjusting for sociodemographic, lifestyle, and technical covariates, and accounted for multiple testing.

FINDINGS

Overall, associations between time in SED and microbiota species abundance were in opposite direction to those for MPA or VPA. For example, MPA was associated with lower, while SED with higher abundance of Escherichia coli. MPA and VPA were associated with higher abundance of the butyrate-producers Faecalibacterium prausnitzii and Roseburia spp. We observed discrepancies between specific VPA and MPA associations, such as a positive association between MPA and Prevotella copri, while no association was detected for VPA. Additionally, SED, MPA and VPA were associated with the functional potential of the microbiome. For instance, MPA was associated with higher capacity for acetate synthesis and SED with lower carbohydrate degradation capacity.

INTERPRETATION

Our findings suggest that sedentary and physical activity are associated with a similar set of gut microbiota species but in opposite directions. Furthermore, the intensity of physical activity may have specific effects on certain gut microbiota species.

FUNDING

European Research Council, Swedish Heart-Lung Foundation, Swedish Research Council, Knut and Alice Wallenberg Foundation.

The combination of trailer transport and exercise increases gastrointestinal permeability and markers of systemic inflammation in horses

BACKGROUND

Leaky gut syndrome (LGS) is an idiopathic disorder characterised by alterations in intestinal permeability and low-grade systemic inflammation. Factors contributing to development of LGS are not well-understood but physiological stressors such as exercise and transport may play a role which may be of pathophysiological relevance in horses.

OBJECTIVES

To characterise the combined effect of transport stress and exercise on gastrointestinal permeability, and to determine whether these effects are associated with increased inflammatory biomarkers in plasma.

STUDY DESIGN

Controlled, randomised and cross-over study.

METHODS

Horses (n = 8 per group) were given a gastrointestinal permeability tracer (iohexol; 5.6% solution; 1 ml/kg bwt) via nasogastric entubation prior to being assigned to a stressed (EX; 1 h of trailer transport immediately followed by 30 min moderate intensity exercise; n = 4) or sedentary control (CON; n = 4) group. Plasma samples were obtained prior to iohexol administration (P1), after transport (P2), at exercise cessation (P3), and at 1 (P4), 2 (P5), 4 (P6) and 8 (P7) hours after cessation of exercise and were analysed for iohexol, inflammatory biomarkers (SAA, LPS, IFABP and LBP) and tight junction proteins (zonulin). Faecal samples were collected at times corresponding to before and after stress from both groups and analysed for zonulin. Data were analysed using a 2-way RM ANOVA.

RESULTS

In EX horses, a significant increase in iohexol was observed at P2 (1.5 ± 0.24 μg/ml; p = 0.03), P3 (2.1 ± 0.29 μg/ml; p < 0.001), P4 (2.1 ± 0.17 μg/ml; p < 0.001) compared with P1 (0.7 ± 0.21 μg/ml); iohexol was significantly higher in EX than CON horses at P3 (p < 0.001), P4 (p < 0.001) and P5 (p = 0.003). LPS and SAA were significantly higher in EX than CON at P4 (p < 0.001) and P6 (p = 0.04), respectively.

MAIN LIMITATIONS

Data from our small sample size may not be generalisable to the larger equine population.

CONCLUSIONS

Combined transport and exercise increases gastrointestinal permeability and systemic SAA and LPS. The model described herein may be useful in further studies on the role of alterations in gastrointestinal permeability in equine disease.

Rat Mucosal Immunity following an Intensive Chronic Training and an Exhausting Exercise: Effect of Hesperidin Supplementation

Stressful situations such as a high-intensity exercise or exhausting training programs can act as immune disruptors leading to transitory immunodepression status, which can be accompanied by alterations of the gastrointestinal functions. Hesperidin intake has demonstrated ergogenic activity and is able to influence the intestinal ecosystem and immunity. We aimed to investigate the effect of hesperidin consumption in rats submitted to an intense training and a final exhaustion test, focusing on the functionality of the intestinal immune system and on the cecal microbiota. Rats, supplemented or not with hesperidin, were intensively trained on a treadmill for 5 weeks. Samples were obtained 24 h after a regular training session, and immediately and 24 h after a final exhaustion test. Cecal microbiota and composition and function of mesenteric lymph node (MLN) lymphocytes and mucosal immunoglobulin A (IgA) were determined. Results showed that chronic intense exercise followed by an exhausting test induced changes in the intestinal immune compartment such as the distribution and function of MLN lymphocytes. Although the hesperidin supplementation did not prevent these alterations, it was able to enhance IgA synthesis in the intestinal compartment. This could be important in enhancing the immune intestinal barrier in this stressful situation.

Influence of Diets Enriched with Flavonoids (Cocoa and Hesperidin) on the Systemic Immunity of Intensively Trained and Exhausted Rats

The aim of this study was to establish the influence of flavonoid-enriched diets on the immune alterations induced by an intensive training and a final exhaustion test in rats. A flavanol-enriched diet (with 10% cocoa, C10 diet) and a flavanol and flavanone-enriched diet (C10 plus 0.5% hesperidin, CH diet) were used. Lewis rats were fed either a standard diet, C10 diet or CH diet while they were submitted to an intensive running training on a treadmill. After 6 weeks, samples were obtained 24 h after performing a regular training (T groups) and after carrying out a final exhaustion test (TE groups). The C10 diet attenuated the increase in plasma cortisol induced by exhaustion, while both the C10 and the CH diets prevented the alterations in the spleen Th cell proportion. The experimental diets also induced an increase in serum immunoglobulin concentration and an enhancement of spleen natural killer cytotoxicity, which may be beneficial in situations with a weakened immunity. Most of the effects observed in the CH groups seem to be due to the cocoa content. Overall, a dietary intervention with flavonoids enhances immune function, partially attenuating the alterations in systemic immunity induced by intensive training or exhausting exercise.

Exercise in Cold Weather for COVID-19-Recovered Individuals (CRI)

Background: The sedentary lifestyle caused by the COVID-19 quarantine has resulted in a devastating threat to human health due to stress and anxiety. Although infected individuals must stop exercising, exercise is not prohibited when without symptoms and complications. Whereas exercise can be effective in immune system reinforcement during the prevention, recovery, and post-recovery stages, COVID-19-recovered Individuals (CRI) must exercise under accurate considerations. Objectives: This study aimed to study exercise in cold weather for the CRI. Methods: This article overviews how different exercises affect the immune system. PubMed, Science Direct, and Google Scholar Databases and keywords including cold weather, COVID-19, immune system, and combined exercise were used to access scientific articles. Results: Recent reports show that different sports and exercises significantly improve COVID-19 symptoms, although there are many discrepancies among researchers in prescribing exercise programs (various training protocols, duration, and intensity). Also, CRI should avoid exercise in cold weather due to breathing complications Conclusions: Based on the present study, regular exercises (aerobic, resistance, and combined) with moderate intensity improve COVID-19 symptoms and the immune system.

A Cocoa Diet Can Partially Attenuate the Alterations in Microbiota and Mucosal Immunity Induced by a Single Session of Intensive Exercise in Rats

Background

Following intensive sports events, a higher rate of upper respiratory tract infections and the appearance of gastrointestinal symptomatology have been reported. We aimed to evaluate the effect of a cocoa-enriched diet on the cecal microbiota and mucosal immune system of rats submitted to high-intensity acute exercise, as well as to elucidate the involvement of cocoa fiber in such effects.

Methods

Wistar rats were fed either a standard diet, a diet containing 10% cocoa providing 5% fiber and a diet containing only 5% cocoa fiber. After 25 days, half of the rats of each diet performed an exhaustion running test. Sixteen hours later, samples were obtained to assess, among others, the cecal microbiota and short chain fatty acids (SCFAs) composition, mesenteric lymph nodes (MLNs) and Peyer’s patches (PPs) lymphocyte composition, and immunoglobulin (Ig) content in salivary glands.

Results

The intake of cocoa, partially due to its fiber content, improved the SCFA production, prevented some changes in PPs and in MLNs lymphocyte composition and also decreased the production of proinflammatory cytokines. Cocoa diet, contrary to cocoa fiber, did not prevent the lower salivary IgM induced by exercise.

Conclusion

A cocoa dietary intake can partially attenuate the alterations in microbiota and mucosal immunity induced by a single session of intensive exercise.

Protective Effect of a Cocoa-Enriched Diet on Oxidative Stress Induced by Intensive Acute Exercise in Rats

Intensive acute exercise can induce oxidative stress, leading to muscle damage and immune function impairment. Cocoa diet could prevent this oxidative stress and its consequences on immunity. Our aim was to assess the effect of a cocoa-enriched diet on the reactive oxygen species (ROS) production by peritoneal macrophages, blood immunoglobulin (Ig) levels, leukocyte counts, and the physical performance of rats submitted to an intensive acute exercise, as well as to elucidate the involvement of cocoa fiber in such effects. For this purpose, Wistar rats were fed either a standard diet, i.e., a diet containing 10% cocoa (C10), or a diet containing 5% cocoa fiber (CF) for 25 days. Then, half of the rats of each diet ran on a treadmill until exhaustion, and 16 h later, the samples were obtained. Both C10 and CF diets significantly prevented the increase in ROS production. However, neither the cocoa diet or the cocoa fiber-enriched diet prevented the decrease in serum IgG induced by acute exercise. Therefore, although the cocoa-enriched diet was able to prevent the excessive oxidative stress induced by intensive exercise, this was not enough to avoid the immune function impairment due to exercise.

Effect of Exhaustive Training or Forced Immobilization on Physiological Condition and Main Metabolic and Stress Markers of Wistar Male Rats

For correct and reliable experimental in vivo assessment of antistress effect of various bioactive substances, appropriate biomodels reproducing stress and organism response to stress in laboratory animals should be chosen. We chose treadmill test for simulating exhaustive physical load and forced immobilization accompanied by disorders of physiological and psychological condition. Verification of the models used indicates their wide applicability for testing certain biological manifestations under reproduced stress exposure.

Is There an Exercise-Intensity Threshold Capable of Avoiding the Leaky Gut?

Endurance-sport athletes have a high incidence of gastrointestinal disorders, compromising performance and impacting overall health status. An increase in several proinflammatory cytokines and proteins (LPS, I-FABP, IL-6, IL-1β, TNF-α, IFN-γ, C-reactive protein) has been observed in ultramarathoners and triathlon athletes. One of the most common effects of this type of physical activity is the increase in intestinal permeability, known as leaky gut. The intestinal mucosa's degradation can be identified and analyzed by a series of molecular biomarkers, including the lactulose/rhamnose ratio, occludin and claudin (tight junctions), lipopolysaccharides, and I-FABP. Identifying the molecular mechanisms involved in the induction of leaky gut by physical exercise can assist in the determination of safe exercise thresholds for the preservation of the gastrointestinal tract. It was recently shown that 60 min of vigorous endurance training at 70% of the maximum work capacity led to the characteristic responses of leaky gut. It is believed that other factors may contribute to this effect, such as altitude, environmental temperature, fluid restriction, age and trainability. On the other hand, moderate physical training and dietary interventions such as probiotics and prebiotics can improve intestinal health and gut microbiota composition. This review seeks to discuss the molecular mechanisms involved in the intestinal mucosa's adaptation and response to exercise and discuss the role of the intestinal microbiota in mitigating these effects.