Endothelial Dysfunction as a result of Hypercaloric Intake: Underlying Mechanism in Absence of Hyperglycemia
Bibliographic record
Abstract
Endothelial dysfunction is a common occurrence in diabetes, secondary to hyperglycemia. However, little is known about the mechanism underlying the early endothelial damage occurring in the course of diabetes development prior to impaired glycemic control. We used a high‐calorie (HC) diet rat model with delayed development of hyperglycemia to address this question. Aortic rings from HC rats exhibited impaired endothelium‐dependent relaxation of phenylephrine (PE)‐induced tone to acetylcholine (ACh), where higher concentrations of ACh caused an increase in contractile tone. On the other hand, similar relaxation patterns to the exogenous nitric oxide (NO) donor, sodium nitroprusside, were observed indicating that the defect is endothelial in origin. Hence, the possible role of an endothelium‐derived contractile agent, such as endothelin‐1 and 20‐HETE, or an increased production of reactive oxygen species due to uncoupling of endothelial NO synthase, as the basis of increased tone caused by higher ACh concentrations was ruled out. In aortic rings from control rats, endothelium‐dependent relaxation to ACh was comprised of a major NO component with a lesser contribution from inward rectifier potassium channel (Kir)‐dependent mechanisms, particularly at higher ACh concentrations. While both components of the response were affected, HC‐feeding appears to abolish the Kir‐dependent pathway completely. Protein levels of Kir 2.1 subunit were down‐regulated in aortic tissues from HC‐fed rats. Using U‐46619, a thromboxane analogue, to evoke contraction involving calcium sensitization, rather than depolarization, aortic rings from control rats demonstrated a NO‐dependent, hyperpolarization‐independent pattern of relaxation in response to ACh. Despite a slightly more blunted response to ACh, HC rings pre‐contracted with U‐46619 did not show the terminal contraction observed in tissues contracted with PE. These results potentially implicate impaired myoendothelial coupling as the underlying mechanism for endothelial dysfunction in diabetes. Further examination of the role and expression of gap junctions in these tissues in under way. Support or Funding Information Supported by AUB MPP fund #320148 This abstract is from the Experimental Biology 2018 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 | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 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 | 0.001 | 0.001 |
| 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".