The effects of relative hyperglycemia on neurovascular coupling magnitude in healthy participants: Impact of biological sex
Bibliographic record
Abstract
Neurovascular coupling (NVC) is a process that ensures adequate blood flow to brain regions with higher metabolic demands, and is one of several mechanisms in place to maintain cerebral blood flow (CBF) and support neuronal homeostasis. Previous research demonstrated the robustness of NVC responses to blood gas challenges. However, other studies found attenuation in NVC responses in individuals with metabolic disorders, and there are well-documented differences in glucose metabolism between males and females. We investigated NVC responses before and after acute oral glucose ingestion, including possible sex-specific differences in healthy males and females. We recruited 36 participants (18 males:18 females) and used transcranial Doppler ultrasound to measure (a) resting cerebral blood velocity (CBV) in the posterior cerebral artery (PCAv) and (a) NVC responses using a series of five visual stimuli (VS) trials (360rpm/6Hz strobe light). Testing occurred before (fasted; FAST) and 30-min after participants ingested a standard 75g/300ml oral glucose drink (glucose loaded; GL) to elicit acute relative hyperglycemia, confirmed via capillary blood sample and glucometer (FAST:4.79±0.36mmol/L; GL:7.55±1.23mmol/L; p<0.0001). We then compared measures of PCAv at rest and during VS to evaluate any sex-specific differences in NVC between FAST and GL states. GL increased baseline PCAv (P=0.005), but this baseline elevation did not affect the dynamic peak NVC response, as evidenced by no changes in metrics of peak responses during the VS post GL (Delta peak: P=0.591; Time-to-peak: P=0.124; Slope: P=0.864). However, the NVC trials resulted in decreased delta mean responses post-GL compared to FAST (P=0.001). When comparing sexes, these responses were observed in males only, with increased baseline PCAv in GL compared to FAST (males:P=0.004; females:P=0.233). This increased baseline CBV resulted in a decreased delta mean NVC responses in males (P=0.002), but not in females (P=0.100). This study adds to the growing body of literature highlighting the stability of peak NVC responses in healthy humans, and demonstrates novel sex-specific baseline CBV and mean NVC responses in acute relative hyperglycemia. In male participants only, we observed an increase in baseline CBV and an attenuated mean NVC response in GL, due to the increased baseline CBV. This work points to future opportunities to explore the acute and chronic effects of clinical hyperglycemia on NVC between sexes. Natural Sciences and Engineering Research Council of Canada (TAD, RGPIN-2016-04915) This abstract was presented at the American Physiology Summit 2025 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 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) | 0.000 | 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 teacher head, 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".