Two-Stage Patterned Cell-Based Treatments for Skin Regeneration

During the process of wound healing, avoiding the formation of aligned collagen fibrils and subsequent scarring has become the focus of numerous research efforts. However, the goal of regeneration of native or scar-free skin remains a challenge. The complex and equivocal connection between inflammation and regeneration within the process of healing contributes to unsatisfactory treatment outcomes. Inspired by the scarless repair observed in fetal wound healing, we create a two-stage treatment combining the hydrocolloid dressing to attenuate the immune response in the initial three days, and the biomimetic cell-laden hydrogel to improve skin regeneration, which meet the specific needs of each stage in the healing process. To further accelerate the skin regeneration, the patterned cell-laden hydrogels were fabricated by photo-mask based photolithography technique. The efficacy and possible mechanisms of skin regeneration using this patterned cell-laden hydrogel therapy was investigated. Results show that these two-stage patterned cell-laden treatments were able to promote vascular network formation, accelerate wound closure, decrease scar formation, increase tissue regeneration and restore structure and mechanical properties of the skin in a full-thickness murine wound model. These data suggest that our patterned cell-based two-stage treatments can be used as a promising therapeutic option for wound healing by accelerating skin tissue regeneration.

Scar-Free Healing: Current Concepts and Future Perspectives

Every year, millions of people develop scars due to skin injuries after trauma, surgery, or skin burns. From the beginning of wound healing development, scar hyperplasia, and prolonged healing time in wound healing have been severe problems. Based on the difference between adult and fetal wound healing processes, many promising therapies have been developed to decrease scar formation in skin wounds. Currently, there is no good or reliable therapy to cure or prevent scar formation. This work briefly reviews the engineering methods of scarless wound healing, focusing on regenerative biomaterials and different cytokines, growth factors, and extracellular components in regenerative wound healing to minimize skin damage cell types, and scar formation.

Fetal Wound Healing

First- and second-trimester fetal skin wounds are known to heal without scarring.Research has excluded factors like the sterile uterine environment as the cause of scarless repair, and it is believed that scarless healing is an intrinsic property of early fetal skin. However, increasing wound size and induction of the inflammatory reaction can evoke a scar response in the fetus.For decades, research is performed to elucidate the mechanisms responsible for scarless healing in fetuses. Much research has been performed in animal studies, and several mechanisms have been proposed to be involved such as the microenvironment and the extracellular matrix, a reduced inflammatory response, differences in growth factor profile, and differences in fibroblast phenotype.It is clear that the wound healing process leading to scarless healing cannot be attributed to just one factor or mechanism but will be the result of a complex of interconnected processes.This chapter describes some of the possible mechanisms which may play a role in scarless healing.