Abstract 13347: Injectable Collagen-based Hydrogel Matrix Modulates Micro-RNA Expression and Prevents Cardiac Deterioration Post-myocardial Infarction
Bibliographic record
Abstract
Background: Injectable hydrogel biomaterials have emerged as promising therapies for treating myocardial infarction (MI). We developed a collagen type I based injectable hydrogel matrix that can prevent the deterioration of cardiac function when delivered soon post-MI and found that the effects may be mediated through a microRNA (miRNA) mechanism. Methods/Results: C57BL/6J mice underwent LAD ligation to induce MI. Mice then received myocardial injections of PBS or matrix delivered at 3hours post-MI. Analyses were performed at 2 days, 1 and 3 months post-treatment. At one month post-treatment, mice that received the matrix had superior left ventricular ejection fraction (LVEF; 45.1±2.3%) compared to the PBS group (29.6±2.4%; p< 0.001). LVEF was maintained in matrix-treated mice at 3 months (42.9±3.8%). Matrix treatment was also associated with reduced infarct sizes and improved ventricular volumes. Matrix-treated mice had more angiogenesis, mitigated apoptosis and reduced inflammation in the infarcted myocardium at both 2 and 28 days post-treatment. To better understand the mechanisms, we performed miRNA microarrays on infarct and peri-infarct tissue. Matrix treatment resulted in 120 miRNAs with differential expression within +/- 0.3 log2 fold change. In particular, we found matrix treatment down-regulated miR-92a ( p< 0.0005), an anti-angiogenic miRNA. Integrins α5 (Itgα5) and αV (ItgαV), involved in angiogenesis and cell-matrix interactions, were identified as putative miR-92a targets and pursued further in vitro using circulating angiogenic cells (CACs). CACs cultured on the matrix had increased Itgα5 and ItgαV expression after 4 days (12.4-fold and 13.9-fold, respectively vs. fibronectin; p< 0.01). When applied in an in vitro angiogenesis assay, the number of CACs that incorporated into capillary-like structures was greater (by 4.2-fold) for cells derived from matrix culture ( p <0.005). Conclusion: We demonstrate pronounced benefits associated with our hydrogel matrix when delivered at 3h post-MI. The matrix effects may be mediated, at least in part, through its ability to regulate miR-92a and integrin-mechanisms. Overall, the matrix may provide a promising therapeutic approach for protecting the myocardium post-MI.
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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) | 0.000 | 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) | 0.003 | 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".