Effect of Chronic Lower Limb Heating on Cutaneous Microvascular Function in Aged Humans
Bibliographic record
Abstract
Cutaneous microvascular function is reduced with advancing age. Recent evidence suggests that chronic local heating of a limb improves cutaneous microvascular function in young healthy humans through nitric oxide‐dependent mechanisms. However, exposure to chronic heating of limb has not been studied in aged adults. The purpose of this study was to test the hypothesis that chronic lower limb heating improves nitric oxide‐dependent vasodilation in the cutaneous microvasculature of aged adults. Six healthy aged adults (5 females; age 67 ± 4 years; height 164 ± 3 cm; weight 70 ± 18 kg; mean ± SD) were exposed to 8 weeks of chronic lower limb heating. Subjects immersed their lower limbs ~33 cm into a heated (~ 42°C) and circulated water bath 4 days per week, for 45 min per session. Before and after the 8‐week regimen, cutaneous blood flow (laser Doppler red blood cell flux) was measured in response to 39 °C heating of a discreet area of skin exposed to chronic heating with and without (control) intradermal microdialysis administration of the nitric oxide synthase inhibitor Nω‐nitro‐L‐arginine methyl ester hydrochloride (L‐NAME; 20 mM). Estimated maximal cutaneous blood flow was assessed in response to combined local heating to 43 °C and intradermal infusion of sodium nitroprusside (56 mM). Cutaneous vascular conductance (CVC) was calculated as red blood cell flux divided by mean arterial pressure and expressed as a percentage of maximal vasodilation (%CVC max ), where appropriate. Cutaneous vascular conductance during 39 °C local heating was unchanged following chronic heating (pre 78 ± 5 %CVC max vs. post 85 ± 7 %CVC max ; P = 0.2). Likewise, nitric oxide‐dependent vasodilation (calculated as the difference between control and L‐NAME sites) did not differ (pre 68 ± 3 % vs. post 64 ± 3 %; P = 0.3). Interestingly, maximal cutaneous vascular conductance increased after chronic heating (pre 1.8 ± 0.1 flux mmHg −1 vs. post 2.4 ± 0.2 flux mmHg −1 ; P < 0.05). Taken together, chronic lower limb heating does not improve nitric oxide‐dependent cutaneous microvascular function during a local thermal provocation in aged adults, an effect that may be superseded by vascular remodeling as maximal vasodilator capacity was increased after the 8‐week regimen. Support or Funding Information National Institutes of Health (GM‐068865 & GM‐117693) This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .
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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".