Influence of substrate stiffness on the phenotype of heart cells
Why this work is in the frame
A frame that forgets how it found something cannot be audited. These are the routes that admitted this work.
Bibliographic record
Abstract
Adult cardiomyocytes (CM) retain little capacity to regenerate, which motivates efforts to engineer heart tissues that can emulate the functional and mechanical properties of native myocardium. Although the effects of matrix stiffness on individual CM have been explored, less attention was devoted to studies at the monolayer and the tissue level. The purpose of this study was to characterize the influence of substrate mechanical stiffness on the heart cell phenotype and functional properties. Neonatal rat heart cells were seeded onto collagen-coated polyacrylamide (PA) substrates with Young's moduli of 3, 22, 50, and 144 kPa. Collagen-coated glass coverslips without PA represented surfaces with effectively "infinite" stiffness. The local elastic modulus of native neonatal rat heart tissue was measured to range from 4.0 to 11.4 kPa (mean value of 6.8 kPa) and for native adult rat heart tissue from 11.9 to 46.2 kPa (mean value of 25.6 kPa), motivating our choice of the above PA gel stiffness. Overall, by 120 h of cultivation, the lowest stiffness PA substrates (3 kPa) exhibited the lowest excitation threshold (ET; 3.5 +/- 0.3 V/cm), increased troponin I staining (52% positively stained area) but reduced cell density, force of contraction (0.18 +/- 0.1 mN/mm(2)), and cell elongation (aspect ratio = 1.3-1.4). Higher stiffness (144 kPa) PA substrates exhibited reduced troponin I staining (30% positively stained area), increased fibroblast density (70% positively stained area), and poor electrical excitability. Intermediate stiffness PA substrates of stiffness comparable to the native adult rat myocardium (22-50 kPa) were found to be optimal for heart cell morphology and function, with superior elongation (aspect ratio > 4.3), reasonable ET (ranging from 3.95 +/- 0.8 to 4.4 +/- 0.7 V/cm), high contractile force development (ranging from 0.52 +/- 0.2 to 1.60 +/- 0.6 mN/mm(2)), and well-developed striations, all consistent with a differentiated phenotype.
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.
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 it