Dexamethasone Promotes Calcium Pyrophosphate Dihydrate Crystal Formation by Articular Chondrocytes
Bibliographic record
Abstract
OBJECTIVE: Calcium pyrophosphate dihydrate (CPPD) crystals are commonly found in osteoarthritic joints and correlate with a poor prognosis. Intraarticular corticosteroids, such as dexamethasone (Dxm), are commonly used therapies for osteoarthritis with or without CPPD deposition. Dxm has variable effects in mineralization models. We investigated the effects of Dxm on CPPD crystal formation in a well established tissue culture model. METHODS: Porcine articular chondrocytes were incubated with ATP to generate CPPD crystals. Chondrocytes incubated with or without ATP were exposed to 1-100 nM Dxm in the presence of 45Ca. Mineralization was measured by 45Ca uptake in the cell layer. We also investigated the effect of Dxm on mineralization-regulating enzymes such as alkaline phosphatase, nucleoside triphosphate pyrophosphohydrolase (NTPPPH), and transglutaminase. RESULTS: Dxm significantly increased ATP-induced mineralization by articular chondrocytes. While alkaline phosphatase and NTPPPH activities were unchanged by Dxm, transglutaminase activity increased in a dose-responsive manner. Levels of Factor XIIIA mRNA and protein were increased by Dxm, while type II Tgase protein was unchanged. Transglutaminase inhibitors suppressed Dxminduced increases in CPPD crystal formation. CONCLUSION: These findings suggest a potential for Dxm to contribute to pathologic mineralization in cartilage and reinforce a central role for the transglutaminase enzymes in CPPD crystal formation.
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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) | 0.002 | 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".