Gastrointestinal barrier dysfunction, endotoxin neutralizing capacity and immuno-inflammatory mediators following repeated exertional heat stress exposure
Bibliographic record
Abstract
Recent evidence in humans has shown a greater endotoxin leakage in sedentary untrained (UT) compared with endurance trained (TR) males at core temperatures below those normally assumed to be essential for the progression of heat illness or heat stroke during acute exertional heat stress (EHS) exposure [1]. Minimal data exists examining the role of gastrointestinal (GI) barrier function, circulating immuno-inflammatory mediators and physiological heat tolerance that accompanies repeated EHS exposures and whether the same cytoprotective responses observed in TR individuals [2] may be induced during repeated EHS in UT. The purpose of this work was to examine the immuno-inflammatory cascades accompanying classical physiological adaptations in untrained males following repeated EHS exposures. Nine UT males (Age = 27 ± 2 years, VO₂peak= 52 ± 2 mL·kgLBM⁻¹·min⁻¹, 17 ± 2% body fatness) walked to exhaustion (EXH) at 4.5 km·h⁻¹ with 2% elevation in a climatic chamber (40°C, 30% R.H.) while wearing encapsulating protective clothing on 9 separate days. Venous whole blood samples were collected at baseline (PRE), 38.0C, 38.5C, 39.0C and EXH on Days 1 and 9, while PRE/EXH samples were drawn on Days 5 and 6. Samples were analyzed for endogenous endotoxin, endotoxin neutralizing capacity (ENC) and for circulating immuno-inflammatory mediators macrophage inflammatory protein (MIP)-1β, IL-6, IL-10, lipopolysaccharide binding protein (LBP), soluble (s) CD14 and extracellular (e) HSP72 by ELISA. In addition, intracellular (i) HSP72 was examined in circulating leukocyte subsets by flow cytometry. Classical physiological adaptations, including reduced HR and increased tolerance time, delta core temperature tolerated, plasma volume and sweat rates were observed during repeated EHS exposure. Mild endotoxemia (21.3 ± 5 pg/mL) was observed at EXH on Days 1, 5, 6, 9 as well as a 14% reduction in ENC (12014 ± 717 vs. 10292 ± 929 ENU/mL) from PRE to EXH on Day 1. Accompanying the changes in endogenous endotoxin and thermoregulatory adaptations were enhanced circulating levels of IL-6, IL-10, LBP, sCD14 as well as cytoprotective increases in both eHSP72 and iHSP72. These findings suggest that GI barrier dysfunction may be an important mechanism of immuno-inflammatory modulation and cytoprotective adaptations observed following repeated EHS exposures.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".