An investigation of a self-assembled cell-extracellular complex and its potentials in improving wound healing

To maintain and enhance the wound healing effects of mesenchymal stem cells (MSCs), a scaffold for hosting MSCs is needed, which ought to be completely biocompatible, durable, producible, and of human source.

To build a cell-extracellular matrix (ECM) complex assembled by human umbilical cord mesenchymal stem cells (HuMSCs) and to investigate its clinical potentials in promoting wound healing.

HuMSCs were isolated and expanded. When the cells of third passage reached confluency, ascorbic acid was added to stimulate the cells to deposit ECM where the cells grew in. Four weeks later, a cells-loaded ECM sheet was formed. The cell-ECM complex was observed under the scanning electron microscopy (SEM) and subjected to histological studies. The supernatants were collected and the cell-ECM complex was harvested at different time points and processed for enzyme-linked immune sorbent assay (ELISA) and mRNA analysis. The in vivo experiments were performed by means of implanting the cell-ECM complex on the mice back for up to 6 months and the specimens were collected for histological studies.

After 4 weeks of cultivation with ascorbic stimulation, a sheet was formed which is mainly composed with HuMSCs, collagen and hyaluronic acid. The cell-ECM complex can sustain to certain tensile force. The mRNA and protein levels of vascular endothelial growth factor-α (VEGF-α), hepatocyte growth factor (HGF), keratinocyte growth factor (KGF), and transforming growth factor-β1 (TGF-β1) were remarkably increased compared to monolayer-cultured cells. The implanted cell-ECM complex on mice was still noticeable with host cells infiltration and vascularization on 6 months.

Our studies suggested that HuMSCs can be multi-cultivated through adding ascorbic stimulation and ECM containing collagen and hyaluronic acid were enriched around the cells which self-assembly formed a cell-ECM complex. Cell-ECM complex can improve growth factors secretion remarkably which means it may promote wound healing by paracrine.