Department of Organ Regulation Medicine

Plastic Surgery

Surgical techniques and research for the restoration of damaged forms and functions of the body and the enhancement of beauty
  • Realization of scarless wound healing in medical treatments
  • Development of new regenerative medicine for peripheral nerve injury using adipose tissue-derived mesenchymal stem cells
  • Elucidation of mechanisms that promote peripheral nerve regeneration
  • Development of new treatments for facial nerve palsy
Professor Ko Hosokawa
Plastic Surgery
Our laboratory is originated from the Plastic Surgery Group in the Laboratory of Dermatological Science back in 1980. Professor Hosakawa succeeded Dr. Koreaki Matsumoto as the Group Leader in 1994. The group became independent in 1999, and was recognized as an individual Laboratory in 2001.

Restoration of forms and functions of the human body by innovative surgical techniques such as tissue transplant using microsurgery.

Our laboratory conducts research on skin wound healing with the aim of realizing scarless wound healing in medical treatments. We also perform studies related to peripheral nerve regeneration mechanism and adipose tissue derived mesenchymal stem cells.

Fibroblasts and myofibroblasts play important roles in skin wound healing. We focus on studying factors involved in cytoskeletal regulation such as RhoA, Rac1 and Cdc42. Previously we discovered that administration of bFGF to fibroblasts improves wound healing by activating Rac1 to promote lamellipodia formation and fibroblast migration, and identified that bFGF promotes fibroblast migration through the PI3-Kinase-Rac1-JNK signal transduction pathway. Moreover, we revealed that endothelin-1, one of vascular endothelial-derived factors, activates RhoA in fibroblasts and induces differentiation into myofibroblasts, leading to the formation of abnormalities such as keloids and hypertrophic scars.

Figure
Endothelial cells in abnormal scar secret endothelin-1. Then, endothelial cell-derived endothelin-1 affects dermal fibroblasts and activates the RhoA/Rho-kinase pathway through the endothelin receptor, which results in myofibroblast differentiation, collagen synthesis, upregulation of contractile properties, and abnormal scar formation.

Facial paralysis is an intractable disorder often encountered in the field of plastic surgery. For the development of novel therapeutic treatments, we focused on similar factors related to wound healing such as RhoA, Rac1 and Cdc42, and clarified the mechanism of axon extension promotion in peripheral nerves. We identified that inhibition of RhoA promotes recovery after motor nerve injury. We are currently also working towards the development of new regenerative medicine for peripheral nerve injury using adipose tissue-derived mesenchymal stem cells.

Furthermore, we developed an innovative model of co-culturing skin fibroblasts and neurons to study the interaction between skin and nerve, which are two seemingly different systems. Using this model, we discovered that upon contact with neurites, differentiation of fibroblasts into myofibroblasts is being promoted hence enhancing wound contraction.

We will continue to further explore the mechanisms behind the above findings, with the aim to ultimately achieve scarless wound healing in medical treatments and full regeneration of peripheral nerve damage.