Microvascular Content and Insulin Sensitivity within Skeletal Muscle and Adipose Tissue Differs between Male and Female Mice on a High‐fat Diet
Bibliographic record
Abstract
Capillary networks within skeletal muscle and adipose tissue have a critical role in the delivery of energy sources and the maintenance of proper tissue function. A reduction in capillary density is correlated with impairments in whole body metabolic functions, as occurs in obesity. It is known that the susceptibility to develop obesity‐associated metabolic disturbances differs between males and females. However, studies investigating these sex‐related differences have largely overlooked the potential contribution of capillary content. The goal of this investigation is to determine whether there are sex differences in skeletal muscle and adipose tissue microvascular content and to relate these to insulin signaling in normal and obese mice. Male mice fed a high‐fat (HF) diet for 16 weeks exhibited reduced systemic insulin sensitivity compared to females who maintained a response similar to the normal‐chow (NC) group. Insulin stimulation increased levels of phosphorylated Akt (pAkt) protein equivalently in the skeletal muscle of male and female NC mice. With HF diet, males had significantly lower insulin‐stimulated pAkt levels vs. females (0.7 vs. 1.9, P <0.0001). Capillary‐to‐fiber ratio was not different in the skeletal muscle of HF male vs. female mice (1.5 vs. 1.4, n=3 ns). Ex vivo insulin stimulation of visceral adipose tissue increased pAkt in HF females but not in HF males. Microvascular content in visceral adipose was not different between NC males and females. In contrast, HF males had reduced, but HF females maintained, their adipose vascular content. This was further supported by higher mRNA levels of vascular marker CD31 (0.17 vs. 0.12, p< 0.05) and pro‐angiogenic factor VEGF (0.14 vs. 0.07, p< 0.05) in HF females vs. HF males. Our data suggest that capillary content and a pro‐angiogenic environment is maintained in the adipose of HF‐fed females, which in turn may be linked with maintained adipose insulin sensitivity. Support or Funding Information CIHR
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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) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.004 | 0.001 |
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".