Articular Cartilage Subpopulations Respond Differently to Cyclic Compression <i>In Vitro</i>
Bibliographic record
Abstract
The inferior biomechanical properties of in vitro-formed tissue remain a significant obstacle in bioengineering articular cartilage tissue. We have previously shown that cyclic compression (30 minutes, 1 kPa, 1 Hz) of chondrocytes isolated from full-thickness cartilage can induce greater matrix synthesis, although articular cartilage is composed of different subpopulations of chondrocytes, and their individual contribution to enhanced tissue formation has not been fully characterized. This study examines the contribution of chondrocyte subpopulations to this response. Bovine articular chondrocytes were isolated from superficial to mid zones (SMZs) or deep zones (DZs), placed in three-dimensional culture, and subjected to cyclic compression. DZ chondrocytes on calcium polyphosphate substrates formed thicker tissue than those from SMZs. Compression increased matrix accumulation in SMZ chondrocytes while decreasing accumulation in DZ chondrocytes. The SMZ and DZ chondrocytes also differed in their type 1 membrane-bound matrix metalloproteinase (MMP) and MMP-13 expression, enzymes that play a crucial role in mediating the response to mechanical stimulation. In addition, the duration of the culture period was important in determining the DZ response, raising the possibility that matrix accumulation plays a role in the response to stimulation. Understanding the cellular response to mechanical stimulation during tissue formation will facilitate our understanding of tissue growth and allow for further optimization of cartilage tissue formation in vitro.
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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 | 0.000 |
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".