Arterial Shear Rate Spectra Associate With Atheroprotection And Are Regulated By Vascular Resistance
Bibliographic record
Abstract
PURPOSE: Endothelial cell culture preparations exposed to pulsatile shear patterns exhibit an atheroprotective phenotype with a positive association between increasing contribution from lower-frequency shear harmonics and increased markers of atheroprotection. The analogous relationship has yet to be established in humans. We therefore evaluated associations between arterial shear rate (SR) waveform spectra and endothelial function [brachial artery flow-mediated dilation (%FMD)] in young healthy humans. METHODS: We used linear regression to explore associations between the most dominant harmonics from arterial SR waveforms and functional measures such as %FMD. Feature selection from ancillary participant data was used to identify candidate mechanisms that regulate spectral characteristics of arterial waveforms. A second, and independent sample of humans was recruited and exposed to local forearm heating and cooling to test the regulating influence of vascular resistance on upstream harmonic profiles. A third set of participants were exposed to exercise and the eliciting arterial waveform profiles were characterized using spectral decomposition. RESULTS: The absolute amplitudes of the first (r = 0.46, P < 0.01) and second (r = 0.48, P < 0.001) SR harmonics associated with greater %FMD. Peripheral resistance was suggested as a relevant feature that regulated spectral characteristics of the arterial SR waveform. Decreasing peripheral resistance using local forearm heating increased spectral shear amplitudes from lower-frequency harmonics (second harmonic, P < 0.01; and third harmonic, P < 0.01). Increased low frequency shear spectra (first harmonic, P < 0.01; second harmonic, P < 0.01) was also observed concomitant with decreases in peripheral resistance during moderate-intensity aerobic exercise on a cycle ergometer. CONCLUSIONS: Leftward shifts in conduit artery SR spectra are regulated by vascular resistance and associate with atheroprotection, likely via endothelial shear sensing. Supported by: Natural Sciences and Engineering Research Council of Canada
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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 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 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) | 0.002 | 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".