Moderate exercise increases endotoxin concentration in hypoxia but not in normoxia

Machado, Paola Próspero; Caris, Aline Venticinque; Santos, Sandra A.; Silva, Edgar; Oyama, Lila M.; Tufik, Sérgio; Santos, Ronaldo Vagner Thomatieli dos

doi:10.1097/md.0000000000005504

Cited by 12 publications

(11 citation statements)

References 11 publications

(15 reference statements)

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“…Our findings of intestinal injury following exercise in HYP expand upon previous investigations using normobaric hypoxia (Hill et al., 2020; Lee & Thake, 2017; Machado et al., 2017). Previous studies have focused on the effect of exercise in hypoxia on markers of intestinal injury but lacked direct evidence of its consequences.…”

Section: Discussionsupporting

confidence: 87%

“…These data are corroborated by Machado et al. (2017) who reported significant elevations in circulating endotoxins following exercise in normobaric hypoxia (14%

{F_{{\rm{i}}{{\rm{O}}_{\rm{2}}}}}

), but not normoxia. Our data also confirm the findings of previous investigations demonstrating increased bacterial translocation following hypoxic exposures in rodent models (Luo et al., 2017; Q.‐Q.…”

Section: Discussionsupporting

confidence: 79%

“…We demonstrated that exercise in HYP results in significant elevations in LBP, which likely indicate a mild endotoxin response. These data are corroborated by Machado et al (2017) who reported significant elevations in circulating endotoxins following exercise in normobaric hypoxia (14% F iO 2 ), but not normoxia. Our data also confirm the findings of previous investigations demonstrating increased bacterial translocation following hypoxic exposures in rodent models (Luo et al, 2017;Q.-Q.…”

Section: Discussionsupporting

confidence: 73%

“…Recently, two groups have shown that moderate intensity running (Hill et al., 2020) and cycling (Lee & Thake, 2017) in normobaric hypoxia increases circulating markers of intestinal injury and proinflammatory cytokines when compared to exercise performed in normoxic conditions. Another study showed that exercise in normobaric hypoxia increases circulating endotoxins (Machado et al., 2017), suggesting increased intestinal permeability and bacterial translocation. However, no study to date has examined exercise‐induced intestinal injury using hypobaric hypoxia, which may present a greater physiological stress than normobaric hypoxia (Beidleman et al., 2014).…”

Section: Introductionmentioning

confidence: 99%

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Exercise in hypobaric hypoxia increases markers of intestinal injury and symptoms of gastrointestinal distress

McKenna

Fennel

Berkemeier

et al. 2022

Experimental Physiology

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New Findings What is the central question of this study?What is the effect of hypobaric hypoxia on markers of exercise‐induced intestinal injury and symptoms of gastrointestinal (GI) distress? What is the main finding and its importance?Exercise performed at 4300 m of simulated altitude increased intestinal fatty acid binding protein (I‐FABP), claudin‐3 (CLDN‐3) and lipopolysaccharide binding protein (LBP), which together suggest that exercise‐induced intestinal injury may be aggravated by concurrent hypoxic exposure. Increases in I‐FABP, LBP and CLDN‐3 were correlated to exercise‐induced GI symptoms, providing some evidence of a link between intestinal barrier injury and symptoms of GI distress. Abstract We sought to determine the effect of exercise in hypobaric hypoxia on markers of intestinal injury and gastrointestinal (GI) symptoms. Using a randomized and counterbalanced design, nine males completed two experimental trials: one at local altitude of 1585 m (NORM) and one at 4300 m of simulated hypobaric hypoxia (HYP). Participants performed 60 min of cycling at a workload that elicited 65% of their NORM trueV̇normalO2max${\dot V_{{{\rm{O}}_{\rm{2}}}{\rm{max}}}}$. GI symptoms were assessed before and every 15 min during exercise. Pre‐ and post‐exercise blood samples were assessed for intestinal fatty acid binding protein (I‐FABP), claudin‐3 (CLDN‐3) and lipopolysaccharide binding protein (LBP). All participants reported at least one GI symptom in HYP compared to just one participant in NORM. I‐FABP significantly increased from pre‐ to post‐exercise in HYP (708 ± 191 to 1215 ± 518 pg ml−1; P = 0.011, d = 1.10) but not NORM (759 ± 224 to 828 ± 288 pg ml−1; P > 0.99, d = 0.27). CLDN‐3 significantly increased from pre‐ to post‐exercise in HYP (13.8 ± 0.9 to 15.3 ± 1.2 ng ml−1; P = 0.003, d = 1.19) but not NORM (13.7 ± 1.8 to 14.2 ± 1.6 ng ml−1; P = 0.435, d = 0.45). LBP significantly increased from pre‐ to post‐exercise in HYP (10.8 ± 1.2 to 13.9 ± 2.8 μg ml−1; P = 0.006, d = 1.12) but not NORM (11.3 ± 1.1 to 11.7 ± 0.9 μg ml−1; P > 0.99, d = 0.32). I‐FABP (d = 0.85), CLDN‐3 (d = 0.95) and LBP (d = 0.69) were all significantly higher post‐exercise in HYP compared to NORM (P ≤ 0.05). Overall GI discomfort was significantly correlated to ΔI‐FABP (r = 0.71), ΔCLDN‐3 (r = 0.70) and ΔLBP (r = 0.86). These data indicate that cycling exercise performed in hypobaric hypoxia can cause intestinal injury, which might cause some commonly reported GI symptoms.

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Section: Discussionsupporting

confidence: 87%

“…These data are corroborated by Machado et al. (2017) who reported significant elevations in circulating endotoxins following exercise in normobaric hypoxia (14%

{F_{{\rm{i}}{{\rm{O}}_{\rm{2}}}}}

Section: Discussionsupporting

confidence: 79%

Section: Discussionsupporting

confidence: 73%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Exercise in hypobaric hypoxia increases markers of intestinal injury and symptoms of gastrointestinal distress

McKenna

Fennel

Berkemeier

et al. 2022

Experimental Physiology

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“…Naturally, it should be noted that different exercise stimuli may lead to adverse impacts on the intestine, also considering their intensity and duration, and the environmental conditions in which they take place. It is known that high altitudes can have adverse effects on the small intestine ( 43 , 44 ) and that high temperatures (hyperthermia) induced by intense exercise may lead to gut ischemia ( 45 ). Also, variations in physical training such as intensity, volume, continuity (alternation between increasing stresses and the proportional recovery period), training time ( 46 ) and fluid restriction during exercise are determinant factors that may contribute to leaky gut ( 8 , 47 , 48 ).…”

Section: Search Strategymentioning

confidence: 99%

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

et al. 2021

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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.

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Aerobic exercise attenuates ectopic renal sinus adipose tissue accumulation-related renal hypoxia injury in obese mice

Wang

Liu

et al. 2021

Life Sciences

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Moderate exercise increases endotoxin concentration in hypoxia but not in normoxia

Cited by 12 publications

References 11 publications

Exercise in hypobaric hypoxia increases markers of intestinal injury and symptoms of gastrointestinal distress

Exercise in hypobaric hypoxia increases markers of intestinal injury and symptoms of gastrointestinal distress

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

Aerobic exercise attenuates ectopic renal sinus adipose tissue accumulation-related renal hypoxia injury in obese mice

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