An MMP/TIMP ratio scoring system as a potential predictive marker of diabetic foot ulcer healing.

OBJECTIVES: The mechanism of matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs) in diabetic foot ulcers (DFUs) is unclear. The purpose of this study was to describe changes in MMP-1, MMP-9, and TIMP-1 levels during DFU healing, and to search for any correlation in the changes in MMP levels with wound healing, in order to find possible predictors of healing. METHODS: Patients with a DFU were recruited and placed into two groups, according to the degree of wound healing: 'good healers' and 'poor healers'. Levels of MMP-1, MMP-9, and TIMP-1 were analysed by ELISA (enzyme-linked immunosorbent assay). RESULTS: A total of 22 patients participated in the study. The MMP-1 level was significantly higher at weeks zero (W0) and 12 (W12) in 'good healers' than in 'poor healers' (p=0.045 and 0.008, respectively). In contrast, the MMP-9 level was significantly lower in 'good healers' than in 'poor healers' at W0, W4, and W12 (p=0.001, 0.001 and 0.028, respectively). Receiver operator curve (ROC) analysis of the MMP-9 level, MMP-1/TIMP-1 ratio, and MMP-9/TIMP-1 ratio at W0 provided cut-off levels of 0.38, 0.056, and 9.06, respectively, which were best predictive of a reduction in wound area at W4 ('good healers' versus 'poor healers'; thereby predicting wound healing condition at W12) with a sensitivity of 81.8%, 81.8%, and 90.9%, and a specificity of 64.6%, 55%, and 64.6%, respectively. CONCLUSION: A 'poor healing scoring system' is therefore proposed that could be determined on patient admission, which has the potential to be used clinically as a predictor of healing, thus allowing an appropriate treatment plan to be developed.

Wound Fluid Matrix Metalloproteinase-9 as a Potential Predictive Marker for the Poor Healing Outcome in Diabetic Foot Ulcers.

BACKGROUND AND OBJECTIVE: Evidence for the roles of matrix metalloproteinases-9 (MMP-9) in the healing process of diabetic foot ulcers has remained unclear. We therefore aimed to demonstrate the relationship of MMP-9 with the wound healing process and determine its potential usefulness in predicting the wound healing outcome. METHODS: Twenty-two patients with diabetic foot ulcer were recruited. The wound size was determined, and the wound fluid was collected for the measurement of MMP-9 levels using an ELISA during the 12-week follow-up period regularly. The patients were categorized as good healers and poor healers when the wound area reduction was ≥ 50% and < 50% at week 4 when compared to the initial wound size at week 0. RESULTS: Median wound fluid MMP-9 levels in the poor healer group were shown to be significantly higher than those in the good healer group (1.03 pg/µg protein vs. 0.06 pg/µg protein, p = 0.001), and the levels fluctuated throughout the 12-week follow-up period. In contrast to the poor healer group, the MMP-9 levels were demonstrated to be constantly low throughout the follow-up period in the good healer group. ROC analysis showed that the MMP-9 level of 0.38 pg/µg protein was able to predict the wound healing outcome with the sensitivity of 81.8%, the specificity of 64.6%, and the area under the curve of 0.901 (CI 0.78-1.03, p = 0.001). CONCLUSION: These findings suggested that determination of wound fluid MMP-9 levels might become a promising biomarker predicting wound healing outcomes and a novel potential therapeutic target for diabetic foot ulcers.