Stepwise Differentiation of Engineered Human Meniscus Tissues in 3D-Printed Flexible Scaffolds
Bibliographic record
Abstract
Background Meniscus injuries are common with approximately 850,000 patients undergoing surgical treatment in the United States yearly. To investigate regenerative strategies for avascular meniscus tears, our lab has been utilizing bovine meniscus explants for investigating regenerative strategies for tears and crosstalk between joint tissues. However, inter-species crosstalk between bovine meniscus and human derived joint tissues remains a concern. This study was designed to engineer and validate a model of human meniscus for engineered healing of avascular meniscus tears under the crosstalk between meniscus, synovial membrane, and IFP. Methods A wedge-shaped scaffold was 3D-printed with Ecoflex F Blend C1200 polymer. Synovial mesenchymal stem/progenitor cells (syMSCs) were isolated from surgically removed synovium of anonymous adult donors as per our previous methods. The scaffolds were then loaded with collagen bioink and 2,000,000 cell /mL syMSCs and then placed into the PDMS molds. Experiment 1: For the first 2 weeks, the tissue constructs were cultured in Fibrogenic induction supplemented (FIS) media with connective tissue growth factor (CTGF). For weeks 3-4, the tissue constructs were cultured in chondrogenic induction supplemented media (CIS) and transforming growth factor beta-3 (TGFβ-3). Experiment 2: For 4 weeks tissue constructs were cultured in FIS with CTGF and CIS with TGFβ-3. No loading was applied. Experiment 3: Tissue constructs were cultured in combined FIS (w/ CTGF) and CIS (w/ TGFβ-3) with no FBS and no loading. Results At 4 weeks, histology showed new tissue integration into the pores throughout the scaffolds. Picrosirius Red (PR) and Alcian Blue (AB) staining suggest the de novo tissues in the no loading group are dense fibrocartilaginous tissues. Polarized images of PR-stained section showed densely aligned collagen fibers, reminiscent of native meniscus, comprising circumferential fibers and radial tie fibers. Mechanical loading resulted in less mature fibrous tissue matrix with limited cartilaginous matrix. Combined culture with FIS (w/ CTGF) and CIS (w/ TGFβ-3) showed the most mature and dense fibrocartilage tissue development after 4 weeks. RNA sequencing data show similar expression levels of fibrochondrocyte-specific genes, including COL1A2, ACAN, COMP, and COL1A1, between engineered and native human meniscus tissue. Conclusion Our study suggests a reliable and effective approach to engineer human meniscus-like tissues that can serve as an experimental explant model for various types of meniscus explant research. Combined culture with FIS and CIS creates more mature fibrocartilage structure than step-wise differentiation under no physiological loading. These findings may have implications for engineering human meniscus-like tissue for various types of meniscus research.
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How this classification was reachedexpand
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 | 0.003 | 0.001 |
| Meta-epidemiology (narrow) | 0.002 | 0.002 |
| Meta-epidemiology (broad) | 0.002 | 0.000 |
| Bibliometrics | 0.011 | 0.011 |
| Science and technology studies | 0.001 | 0.004 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.004 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.008 | 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; both teacher heads agree on what is shown here.
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".