Aged bovine chondrocytes display a diminished capacity to produce a collagen-rich, mechanically functional cartilage extracellular matrix
Bibliographic record
Abstract
Most fundamental studies in cartilage tissue engineering investigate the ability of chondrocytes from young animals to produce cartilaginous matrix under various conditions, while current clinical applications such as autologous chondrocyte implantation, use chondrocytes from donors that are decades past skeletal maturity. Previous investigations have suggested that several characteristics of primary chondrocytes are age-dependent but none have quantified cell proliferation, proteoglycan synthesis and accumulation, collagen synthesis and accumulation, compressive and tensile mechanical properties in order to examine the effects of donor age on all of these parameters. We enzymatically isolated primary bovine chondrocytes from fetal, young and aged animals and cultured these cells in agarose gels to assess the above-mentioned properties. We found that fetal and young (but still skeletally mature i.e. 18-month-old bovine) chondrocytes behaved similarly, while aged chondrocytes (5- to 7-year-old bovine) displayed diminished proliferation ( approximately 2x less), a slightly reduced proteoglycan accumulation per cell ( approximately 20%), and significantly less collagen accumulation per cell ( approximately 55%) compared to the younger cells. Histological observations and mechanical properties supported these findings, where a particularly significant reduction in tensile stiffness produced by aged chondrocytes compared to younger cells was observed. Our findings suggest that donor age is an important factor in determining the outcome and potential success when tissue-engineered cartilage is produced from articular chondrocytes. More specifically, primary chondrocytes from aged donors may not possess sufficient capacity to produce the extracellular matrix that is required for a mechanically resilient tissue.
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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) | 0.001 | 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".