Short Term Effects of Doxycycline on Matrix Metalloproteinases 2 and 9

Purpose To investigate the short term effects of Doxycycline on MMP-2 and MMP-9. Methods Short term effects of Doxycycline (100 mg B.I.D.) on plasma levels of MMP-2 and MMP-9 were investigated in 20 healthy subjects; the effects of Doxy, Acetylsalicylic acid, Nitrates, and Enalapril on MMP-9 release from were assessed in isolated polymorphonuclear cells. Results In plasma, MMP-9 activity was reduced (-22%, 95% CI -32/-11; P=0.002) starting at 12 h after doxy; in vitro, MMP-9 released from stimulated neutrophils was reduced by Doxy (-28%, 95% CI -43/-14; P=0.001), inhibiting degranulation, and by nitrates (-52%, 95% CI -76/-28 P= 0.005), increasing three times both pro- and active-MMP-9 bound to neutrophils (P=0.007 and 0.040, respectively). Conclusions Doxy decreases MMP-9 plasma levels by around 20%, within the first 12 h. The mechanism leading to such reduction seems due to the inhibition of PMN degranulation.