Effect of the Menstrual Cycle on Vasodilatory Responses to Standard and Enhanced Flow‐ Mediated Dilation Stimuli
Bibliographic record
Abstract
Flow‐mediated dilation (FMD) is a clinical index of endothelial health that has not revealed consistent differences between the sexes or the phases of the menstrual cycle, both of which are known to affect endothelial function. Since estradiol varies with the menstrual cycle and up‐regulates nitric oxide, a primary mediator of the FMD response, it is surprising that past studies have not revealed consistent associations between FMD and menstrual cycle phase. It may be that the standard FMD is not sensitive enough to reflect the subtle changes in endothelial function which occur across the menstrual cycle. Recent data suggest that enhanced FMD stimuli provide a potential means for detecting subtle changes in endothelial function that are not observed using the standard FMD. We hypothesized that an enhanced FMD stimulus, as elicited by 3 min of forearm occlusion concomitant with isometric handgrip exercise at 30% of maximal voluntary contraction (IEFMD), will be more responsive to menstrual cycle‐induced changes in estradiol (and therefore vasodilatory responsiveness) than the standard 5‐min FMD in young healthy women. We compared reactive hyperemic responses (%FMD) between FMD protocols (i.e. standard FMD vs. IEFMD) in eumenorrheic women (n: 4; age: 21±1.4 yrs, range: 19–22 yrs, BMI: 23.3±3.2 kg/m 2 , range: 20.5–26.4 kg/m 2 , cycle length: 29.8±1.7 days, range: 28–32 days) during the low‐estradiol early follicular phase of the menstrual cycle (EF; days 1–5) and the high‐estradiol late follicular phase (LF; days 10–14). As expected, we observed a greater %FMD in response to the IEFMD relative to the standard FMD in the EF phase (19.4±4.6% vs. 9.0±1.6% respectively, p<0.05). Similarly, in the LF phase we observed a trend toward a greater %FMD in the IEFMD versus the standard FMD (13.5±5.8% vs. 7.0±0.04%, p=0.1). However, a two‐way ANOVA demonstrated no main effect of menstrual cycle phase (p=0.5), or FMD stimulus (p=0.7) on %FMD (phase x stimulus interaction: p=0.9). Therefore, these preliminary data do not support our hypothesis that an enhanced FMD stimulus involving isometric handgrip exercise is more sensitive than the standard FMD in detecting changes in endothelial function across menstrual cycle phases in young healthy women. Support or Funding Information This project was supported by a Natural Sciences and Engineering Research Council Discovery Grant (CWU). TEA & YC were supported by the McGill Department of Kinesiology and Physical Education Graduate Excellence Fellowship. This abstract is from the Experimental Biology 2019 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 | 0.001 | 0.001 |
| 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".