Autophagy And Apoptosis In Immune Cells Of Older Adults During Day-long Exposure To Indoor Overheating
Bibliographic record
Abstract
Most heat-related deaths during an extreme heat event occur indoors. Consequently, an upper indoor temperature limit of 26 °C has been proposed by public health officials as sufficient to protect older heat-vulnerable occupants. We recently showed that a daylong exposure to high ambient temperatures (40 °C) disrupts cellular protective mechanisms, including autophagy, placing older adults at increased risk of heat-induced cellular injury. Whether similar responses occur at lower ambient temperatures observed in dwellings during hot weather or extreme heat events is currently unknown. PURPOSE: We evaluated autophagy and apoptosis during day-long exposures to a range of ambient temperatures typical of homes with and without access to air-conditioning (A/C) during hot weather (22-36 °C). METHODS: On separate days, peripheral blood mononuclear cells were harvested from 16 older adults (aged 66-78 years) prior to and following 8 h of rest in ambient conditions simulating homes maintained at 22 °C and 26 °C (e.g., with A/C), as well as homes without A/C (31 and 36 °C; all 45% relative humidity). Rectal temperature (Tre) was measured throughout, while proteins associated with autophagy (LC3-II) and apoptosis (cleaved-caspase-3 [Casp3]) were assessed via Western blot (normalized to β-actin and reported as relative quantity [RQ] from the respective baseline). Data were compared using a one-way ANOVA with Bonferroni post-hoc analysis (α = 0.05). RESULTS: Compared to 22 °C, a clinically significant elevation (>0.3 °C) in Tre was observed during the 31 and 36 °C exposures (+0.7 °C and + 0.9 °C, respectively, both p < 0.001), but not at 26 °C (p = 0.17). LC3-II and Casp3 were not significantly different from the 22 °C condition during exposure to 26 or 31 °C (all p ≥ 0.16). However, LC3-II and Casp3 were elevated during the 36 °C exposure (1.9 RQ [SD 1.4] and 2.5 [2.4], respectively) when compared to 22 °C (0.9 [0.4] and 0.6 [0.2], p ≤ 0.04). CONCLUSION: We show that maintaining indoor temperature at or below 26 °C, protects against both an increase in core temperature and cellular disruption as evidenced by normal autophagic and apoptotic responses. While a progressive increase in core temperature occurred at 31 and 36 °C, altered cellular function was only observed at 36 °C. FUNDING: Canadian Institutes for Health Research (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".