Diminished cartilage‐lubricating ability of human osteoarthritic synovial fluid deficient in proteoglycan 4: Restoration through proteoglycan 4 supplementation
Bibliographic record
Abstract
OBJECTIVE: The purposes of this study were 1) to quantify the proteoglycan 4 (PRG4) and hyaluronan (HA) content in synovial fluid (SF) from normal donors and from patients with chronic osteoarthritis (OA) and 2) to assess the cartilage boundary-lubricating ability of PRG4-deficient OA SF as compared to that of normal SF, with and without supplementation with PRG4 and/or HA. METHODS: OA SF was aspirated from the knee joints of patients with symptomatic chronic knee OA prior to therapeutic injection. PRG4 concentrations were measured using a custom sandwich enzyme-linked immunosorbent assay (ELISA), and HA concentrations were measured using a commercially available ELISA. The molecular weight distribution of HA was measured by agarose gel electrophoresis. The cartilage boundary-lubricating ability of PRG4-deficient OA SF, PRG4-deficient OA SF supplemented with PRG4 and/or HA, and normal SF was assessed using a cartilage-on-cartilage friction test. Two friction coefficients (μ) were calculated: static (μ(static, Neq) ) and kinetic (<μ(kinetic, Neq) >) (where N(eq) represents equilibrium axial load and angle brackets indicate that the value is an average). RESULTS: The mean ± SEM PRG4 concentration in normal SF was 287.1 ± 31.8 μg/ml. OA SF samples deficient in PRG4 (146.5 ± 28.2 μg/ml) as compared to normal were identified and selected for lubrication testing. The HA concentration in PRG4-deficient OA SF (mean ± SEM 0.73 ± 0.08 mg/ml) was not significantly different from that in normal SF (0.54 ± 0.09 mg/ml). In PRG4-deficient OA SF, the molecular weight distribution of HA was shifted toward the lower range. The cartilage boundary-lubricating ability of PRG4-deficient OA SF was significantly diminished as compared to normal (mean ± SEM <μ(kinetic, Neq) > = 0.043 ± 0.008 versus 0.025 ± 0.002; P < 0.05) and was restored when supplemented with PRG4 (<μ(kinetic, Neq) > = 0.023 ± 0.003; P < 0.05). CONCLUSION: These results indicate that some OA SF may have decreased PRG4 levels and diminished cartilage boundary-lubricating ability as compared to normal SF and that PRG4 supplementation can restore normal cartilage boundary lubrication function to these OA SF.
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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 | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| 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 itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, 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".