Klotho And Ngal Responses To Exercise-heat Stress In Older Men With And Without Type-2 Diabetes
Bibliographic record
Abstract
Klotho is a protein expressed by the kidneys and is vital in protecting cellular function during acute physiological stressors (e.g., inflammation, oxidative stress), as occurs during exercise-heat stress. We previously showed that serum klotho concentrations are blunted in healthy older men, with further impairments in older men with type 2 diabetes (T2D) during prolonged exercise in the heat. These altered klotho responses may increase vulnerability to heat-induced cellular injury and consequently increase the risk of acute kidney injury (AKI). However, biomarkers of AKI, such as neutrophil gelatinase-associated lipocalin (NGAL), have yet to be evaluated in the context of blunted klotho production during an exercise-heat stress in older adults with T2D. PURPOSE: We evaluated serum concentrations of klotho and NGAL during exercise-heat stress in older men with and without T2D. METHODS: 28 habitually active older (60 ± 6 years) men with (n = 14, T2D) and without (n = 14, Control) controlled T2D performed 3 successive 30-min cycling bouts in a whole-body air calorimeter in the heat (40 °C, ~15% relative humidity) at fixed rates of metabolic heat production of 150, 200, and 250 W·m2 (to maintain a fixed thermal drive for heat loss), each separated by 15-min rest. Concentrations of klotho and NGAL were assessed via an ELISA at baseline and following the final exercise bout (end-exercise). Statistical significance was determined via a two-way ANOVA with fisher LSD (α = 0.05). RESULTS: Serum NGAL concentrations increased similarly at end-exercise in T2D and controls (+704 pg/mL [SD: 1326] and + 964 pg/mL [1399], respectively, both p < 0.05). Despite this, serum klotho concentrations did not differ in response to exercise in the heat, yet concentrations were higher in the controls at baseline (1593 pg/mL [1318] vs 743 [431] pg/mL; p = 0.038) and at end-exercise (1614 pg/mL [1407] vs 761 pg/mL [465]; p = 0.017) compared to T2D. CONCLUSION: A similar increase in circulating NGAL concentrations between men with and without T2D may indicate a greater vulnerability to AKI during exercise-heat stress. Paired with reduced circulating klotho concentrations in older men with T2D, this may further predispose these individuals to heat-related cellular injury. FUNDING SUPPORT: Canadian Institutes of Population Health (399434)
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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".