Global, but not chondrocyte-specific, MT1-MMP deficiency in adult mice causes inflammatory arthritis

Membrane-type I metalloproteinase (MT1-MMP/MMP14) plays a key role in various pathophysiological processes, indicating an unaddressed need for a targeted therapeutic approach. However, mice genetically deficient in Mmp14 show severe defects in development and growth. To investigate the possibility of MT1-MMP inhibition as a safe treatment in adults, we generated global Mmp14 tamoxifen-induced conditional knockout (Mmp14kd) mice and found that MT1-MMP deficiency in adult mice resulted in severe inflammatory arthritis. Mmp14kd mice started to show noticeably swollen joints two weeks after tamoxifen administration, which progressed rapidly. Mmp14kd mice reached a humane endpoint 6 to 8 weeks after tamoxifen administration due to severe arthritis. Plasma TNF-α levels were also significantly increased in Mmp14kd mice. Detailed analysis revealed chondrocyte hypertrophy, synovial fibrosis, and subchondral bone remodeling in the joints of Mmp14kd mice. However, global conditional knockout of MT1-MMP in adult mice did not affect body weight, blood glucose, or plasma cholesterol and triglyceride levels. Furthermore, we observed substantial expression of MT1-MMP in the articular cartilage of patients with osteoarthritis. We then developed chondrocyte-specific Mmp14 tamoxifen-induced conditional knockout (Mmp14chkd) mice. Chondrocyte MT1-MMP deficiency in adult mice also caused apparent chondrocyte hypertrophy. However, Mmp14chkd mice did not exhibit synovial hyperplasia or noticeable arthritis, suggesting that chondrocyte MT1-MMP is not solely responsible for the onset of severe arthritis observed in Mmp14kd mice. Our findings also suggest that highly cell-type specific inhibition of MT1-MMP is required for its potential therapeutic use.

Effect of Tart Cherry on Aromatase Inhibitor-Induced Arthralgia (AIA) in Nonmetastatic Hormone-Positive Breast Cancer Patients: A Randomized Double-Blind Placebo-Controlled Trial

BACKGROUND

Aromatase Inhibitor induced Arthralgia (AIA) can cause noncompliance leading to decreased breast-cancer survival. Effective interventions for AIA are limited. Tart cherry (TC) showed beneficial effect on musculoskeletal pain. 48 patients (Pts) randomized to TC versus placebo over 6 weeks, TC (23pts) had 34.7% mean pain decrease versus 1.4% in Placebo (25pts). TC can improve AIA in nonmetastatic breast-cancer patients.

METHODS

Randomized, placebo-controlled, double-blind trial. Eligible patients with NMHPBC on AI for at least 4 weeks were randomized to TC concentrate [50 tart cherries] vs. placebo (P) [syrup] in 1:1 model. Patients instructed to consume 1 Oz of concentrate in 8 Oz water daily for 6 weeks, and document their pain intensity at baseline, weekly and at study completion in a diary using Visual Analog Scale (VAS), with 0 mm indicating no pain, and 100 mm indicating highest pain.

RESULTS

Sixty patients were enrolled. Two patients did not complete the study due to diarrhea, and 10 patients were noncompliant. Forty-eight patients were included in the final analysis. TC group (23 pts) had 34.7% mean decrease in pain compared to 1.4% in P group (25 pts). This difference was statistically significant (Mann-Whitney U Test, P = .034).

CONCLUSIONS

Tart cherry can significantly improve AIA in nonmetastatic breast cancer patient.