Effects of Collagen Wound Matrix-Micronized on Fibroblast Function and Protease

Introduction: The interplay between fibroblasts and extracellular matrix (ECM) proteins is an important factor in the normal wound healing cascade. Matrix metalloproteinases (MMPs) are central to the normal breakdown and remodeling of ECM; however, MMP dysregulation is often a factor in chronic wounds. Collagen Wound Matrix-Micronized (CWM-MZ*) is a biocompatible, acellular native collagen powder with a large surface area enhancing contact with the wound bed. In this study, fibroblasts were exposed to a simulated wound fluid (SWF) to model a stressed environment in vitro and responses to CWM-MZ were measured.Methods:An in vitro model using transwell inserts with SWF was used to measure the effects of CWM-MZ on primary fibroblasts in the presence and absence of proteases. Fibroblasts were seeded on the bottom well of culture vessels, with SWF and CWM-MZ applied in the transwell, allowing for direct observation of fibroblast responses. Immunofluorescence staining for collagen I, vimentin, and actin was done. Collagenase II (50 or 25 CDU/mL) was added to the transwell model with CWM-MZ to assess the effect of proteases on cell viability (CellTiter-Glo®) after a 4-hour incubation. A wound scratch assay was done evaluating the effects of conditioned media containing SWF + elevated proteases (SWF + COL; 15 CDU/mL) in the context of CWM-MZ.Results:In the in vitro SWF model, cells cultured in the presence of CWM-MZ exhibited normal cell growth and morphology, along with more robust collagen I expression compared to cells cultured in SWF only. Fibroblast viability with COL or COL + CWM-MZ was 42% vs 95% at 25 CDU/mL and 35.6% vs 75% at 50 CDU/mL, respectively. Using the wound scratch assay, SWF + CWM-MZ showed the fastest closure rate compared to the SWF-only group (p=0.002), followed by SWF + COL + CWM-MZ (p=0.03).Discussion: These studies illustrate the effects of CWM-MZ on proteases and fibroblast function in vitro.References: