DEVELOPMENT OF ARTIFICIAL TRACHEA USING CULTURED CELL SHEET

2002 Fiscal Year Final Research Report Summary

• Project/Area Number: 12470278
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Thoracic surgery
• Research Institution: St. MARIANNA UNIVERSITY SCHOOL OF MEDICINE
• Principal Investigator: OSADA Hiroaki St. MARIANNA UNIVERSITY SCHOOL OF MEDICINE, PROFESSOR, 医学部, 教授 (90121178)
• Co-Investigator(Kenkyū-buntansha): TSUKADA Hisashi St. MARIANNA UNIVERSITY SCHOOL OF MEDICINE, ASSISTANT, 医学部, 助手 (60308476) ; INOUE Hajime St. MARIANNA UNIVERSITY SCHOOL OF MEDICINE, ASSISTANT PROFESSOR, 医学部, 講師 (60193603) ; YOKOTE Kumio St. MARIANNA UNIVERSITY SCHOOL OF MEDICINE, ASSOCIATE PROFESSOR, 医学部, 助教授 (40174859)
• Project Period (FY): 2000 – 2002
• Keywords: ARTIFICIAL TRACHEA / TRACHEAL RECONSTRUCTION / REGENERATION TRACHEA

Research Abstract

Objective : This study was designed to evaluate how various sizes and densities of pores in Dacron tubing may enhance its utility as a tracheal prosthesis.
Methods : Straight vascular prosthesis made of knitted external velour polyester (MICRON) was prepared for pore formation by laser ablation. Two series of experiments were performed to evaluate porosity and porous grafts reinforced with a steel stent. The primary series compared different pore sizes (300μm, 500μm and 700μm) and pore densities (25/cm^2 or 100/cm^2). Grafts were reinforced with an externally heat-sealed silicone ring stent. The second series tested grafts with a pore density of 64/cm^2 and pore size of 500 μm internally reinforced with a stainless steal spiral stent. In all experiments, a 10-cartilage-ring-length of canine mediastinal trachea was resected and prosthesis was then implanted with omantal flap.
Result : Lower pore sizes and densities (300 μm, 25 pores/cm^2) led to essentially no tissue ingrowth. The larger sized pores(700 μm) and density(25 pores/cm^2) led to rapid but excessive ingrowth of granulation tissue. Mid-range pore size (500 μm) and density(100 pores/cm^2) invited steady tissue ingrowth of the entire graft but eventually developed marked luminal stenosis. Stent reinforced prosthesies harboring 500 μm pores at 64 pores/cm^2 maintained an average patency rate of 60% or more (range : 100% to 20%) at least 12 months after implantation.
Conclusion : Our data shows that porosity can enhance the ability for tissue to grow into these tracheal prosthesies. The optimal pore size and density has been found to be approximately 500 μm and 64 pores/cm^2 respectively. Reinforcement of these grafts has also worked well up to 24 months after surgery. This artificial trachea model has led to long-term survivors and seems promising as a basic model for clinical tracheal repair.