Mesenchymal stem cells' seeded amniotic membrane as a tissue-engineered dressing for wound healing.

Different biomaterials have been used as biological dressing for wound regeneration. For many decades, human amniotic membrane graft (AM) has been widely applied for treating acute and chronic wounds. It has minimal toxicity and immunogenicity, supports mesenchymal cell in-growth, improves epidermal cell adherence and proliferation, and finally is inexpensive and readily available. Enrichment of tissue grafts with the stem cells is a new approach to improve their regenerative effects. This animal study aimed at investigating feasibility, safety, and efficacy of tissue-engineered dressings composed of AM and two different types of mesenchymal stem cells (MSCs) in the excisional wound model in rats. Human adipose-derived MSCs (ADMSCs) and placenta-derived MSCs (PLMSCs) were manufactured from the donated adipose and placenta tissues respectively. After cell characterization, MSCs were seeded on acellular AM (AAM) and cultivated for 5 days. Excisional wound model was developed in 24 male Wistar rats that were randomly classified into four groups including control, AAM, ADMSCs + AAM, and PLMSCs + AAM (n = 6 in each group). Tissue-engineered constructs were applied, and photographs were taken on days 0, 7, and 14 for observing the wound healing rates. In days 7 and 14 post-treatment, three rats from each group were euthanized, and wound biopsies were harvested, and histopathologic studies were conducted. The results of wound closure rate, re-epithelialization, angiogenesis, and collagen remodeling demonstrated that in comparison with the control groups, the MSC-seeded AAMs had superior regenerative effects in excisional wound animal model. Between MSCs group, the PLMSCs showed better healing effect. Our data suggested that seeding of MSCs on AAM can boosts its regenerative effects in wound treatment. We also found that PLMSCs had superior regenerative effects to ADMSc in the rat model of excisional wound.