ABSTRACT
BACKGROUND: Chronic skin wounds are a common complication of many diseases such as diabetes. Various traditional methods for assessing skin wound closure are used in animal studies, including wound tracing, calliper measurements and histological analysis. However, these methods have poorly defined wound closure or practical limitations. Digital image analysis of wounds is an increasingly popular, accessible alternative, but it is unclear whether digital assessment is consistent with traditional methods. This study aimed to optimise and compare digital wound closure assessment with traditional methods, using a diabetic mouse model. Diabetes was induced in male C57BL/6J mice by high-fat diet feeding combined with low dose (65 mg/kg of body weight) streptozotocin injections. Mice fed normal chow were included as controls. After 18 weeks, four circular full-thickness dorsal skin wounds of 4 mm diameter were created per mouse. The wounds were photographed and measured by callipers. Wound closure rate (WCR) was digitally assessed by two reporters using two methods: wound outline (WCR-O) and re-epithelialisation (WCR-E). Wounded skin tissues were collected at 10-days post-wounding and wound width was measured from haematoxylin and eosin-stained skin tissue. RESULTS: Between reporters, WCR-O was more consistent than WCR-E, and WCR-O correlated with calliper measurements. Histological analysis supported digital assessments, especially WCR-E, when wounds were histologically closed. CONCLUSIONS: WCR-O could replace calliper measurements to measure skin wound closure, but WCR-E assessment requires further refinement. Small animal studies of skin wound healing can greatly benefit from standardised definitions of wound closure and more consistent digital assessment protocols.
ABSTRACT
OBJECTIVE: This study aimed to identify potential biomarkers reported in wound fluid of diabetes-related foot ulcers (DRFUs), and their ability to reflect current and prospective wound healing. METHOD: A systematic search was executed following the PRISMA methodology across five chosen databases: MEDLINE, Embase, Scopus, Cochrane Clinical Trials and Cochrane Systematic Reviews. Using keywords and phrases, it yielded 5022 results. RESULTS: Based on predetermined inclusion and exclusion criteria, 19 papers were included in the final analysis, among which: seven reported serial temporal biomarker changes in wounds; six reported measures from baseline and related them to healing rate and/or final healing outcome; four papers reported both end-points, and two papers reported solely on baseline biomarker levels in a generalised diabetic foot ulcer group. Across the studies, a total of 46 distinct markers were described from the wound fluid of n=1141 participants. Biomarkers examined included proteases, protease inhibitors, growth factors, chemokines and cytokines, with proteases being the largest subcategory making up 16 (34.8%) of the markers investigated (n=7). Matrix metalloproteinase-9 (MMP-9) was the most frequently investigated protease and it currently holds the most biomarker promise (n=5). Wound bacterial profiles variably related to wound healing outcome (n=5). One study reported biophysical markers rather than biomarkers, including measurement of wound fluid pH. Study quality was generally good. Drawing quantitative comparisons between papers was not possible due to variability in experimental design including sampling and assessment methods. CONCLUSION: These studies collectively indicate several wound fluid measures that could identify DRFU status and outcomes, and that methodological standardisation in the field is needed to determine reliable predictive thresholds for healing.
