**6.2 Targeting matrix metallopeptidase 9 (MMP-9) in diabetic foot ulcers**

Wound healing can be hampered by stress. Cortisol, a steroid hormone, is increased during stress and chronic inflammation, and it slows wound healing Elevated Matrix metallopeptidase-9 levels that have been linked to higher cortisol levels in individuals with coronary artery disease. Prostaglandin E2 has been shown to increase cortisol release and to activate matrix metallopeptidase-9 [58]. One of the causes of the recalcitrance is the increased activity of the enzyme matrix metalloproteinase (MMPs). The preferred substrates of MMPs, such as gelatinases (MMP-2 and MMP-9), collagenases (MMP-1, MMP-8, and MMP-13), and stromelysins, are characterized in a variety of ways (MMP-3 and MMP-10). A second generation of orally bioactive broad-spectrum inhibitors was created as a result of the first generation of MMPIs being broad-spectrum zinc chelators with low bioavailability [59]. The medication becaplermin Gelatinase activity was reduced, but collagenase activity was *Targeting Matrix Metallopeptidase 9 (MMP-9) and Role of Quorum Sensing (QS) in Diabetic… DOI: http://dx.doi.org/10.5772/intechopen.106514*

unaffected; active MMP-9 was reduced, while active MMP-8 was unaffected [60]. MMP expression and activity may be significantly impacted by diabetic foot ulcer treatments that do not directly target matrix metallopeptidase. Most researches have concentrated on the effects on this proteinase specifically since MMP-9 has long been of interest in wound healing [61].
