High Fat Feeding Blunts Skeletal Muscle Oxygen Mediated Blood Flow Responses in Healthy and Type 2 Diabetic Rats
Bibliographic record
Abstract
Hypothesis: High fat diet feeding impairs microvascular blood flow responses to dynamic changes in local oxygen concentration ([O 2 ]) in Sprague-Dawley (SD) and Zucker Diabetic Sprague-Dawley (ZDSD) rats. Methods: Seven-week-old male SD and ZDSD rats were fed either a standard chow (N = 7 SD, 5 ZDSD) or a high saturated fat diet (N = 8 SD, 6 ZDSD) for 7 weeks. At 14 weeks of age animals were anaesthetized, instrumented for systemic monitoring, and mechanically ventilated. The extensor digitorum longus muscle was blunt dissected and reflected over a gas exchange chamber imbedded in the stage of an inverted microscope. Microvascular blood flow responses to high and low [O 2 ] challenges (7 – 12 %, and 7 – 2 %) and sequential changes in [O 2 ] (7 – 12 – 2 – 7 %) were recorded at baseline and during hyperinsulinemic-euglycemic clamp. Gas conditions within the chamber were set at 7 % for a 1-minute baseline followed by 2 minutes at either 2 or 12 % O 2 . The 4-minute square wave oscillation consisted of 1 minute at each [O 2 ] (7 – 12 – 2 – 7 %). Hyperinsulinemic-euglycemic clamp was achieved by simultaneous infusion of insulin (2 U/hr/kg) and variable rate of 50 % glucose until euglycemia was reached (5 - 7 mM blood glucose). Analysis of intravital videos was completed using custom MATLAB software. All animal protocols were approved by Memorial University’s Animal Care Committee. Results: Chow fed SD had significantly higher glucose infusion rates compared to high fat fed SD, chow fed ZDSD, and high fat fed ZDSD (28.11 ± 1.807 vs. 25.14 ± 1.18, 24.56 ± 2.78, 24.77 ± 2.43 mg/kg/min, p = 0.0429, 0.0305, 0.0323, respectively). Red blood cell (RBC) saturation significantly increased and decreased in all groups within 4 s following the increase and decrease in [O 2 ], respectively. Chow fed SD had significant decrease in RBC supply rate (SR) in response to 12 % [O 2 ] (10.41 ± 11.31 vs 7.44 ± 8.40 cells/s, p < 0.0001, τ = 15.85 s). In response to low [O 2 ], significant increases in SR were measured in the chow fed SD and ZDSD groups (7.10 ± 8.76 vs 11.65 ± 11.36 cells/s, p < 0.0001, τ = 17.65 s, and 10.86 ± 13.62 vs 13.86 ± 14.69 cells/s, p < 0.0001, τ = 85.74 s, respectively). High fat fed SD and ZDSD had significant increases in RBC SR during 2 % [O 2 ] (8.47 ± 9.75 vs 11.84 ± 12.11 cells/s, p < 0.0001, τ = 68.49 s, and 16.09 ± 18.12 vs 20.73 ± 21.92 cells/s, p < 0.0001, τ = 23.98 s). High fat fed ZDSD had higher, but not significantly different, baseline RBC SR compared to the chow fed ZDSD group. Chow fed SD were the only group to have an increase in RBC SR at low [O 2 ] during hyperinsulinemic-euglycemic clamp (13.80 ± 17.78 vs 18.07 ± 20.25 cells/s, p = 0.0003, τ = 10.88 s). Conclusions: High fat feeding impairs the capillary blood flow response to local increases in [O 2 ] in healthy and high fat fed T2D model rats. Chow fed ZDSD rats had slower capillary blood flow dynamics than the SD control group. Hyperinsulinemic-euglycemic clamp diminishes the O 2 mediated blood flow response in 14-week-old SD and ZDSD rats fed a high fat diet. This project was supported by the Canadian Institute of Health Research through a project grant to GMF. Studentships were supported by Memorial University's School of Graduate Studies and the Faculty of Medicine. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology 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 | 0.000 |
| 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) | 0.000 | 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".