Effect of Decellularization and Polyethylene Glycol pretreatment on Physico-mechanical Properties and Anticalcification of Glutaraldehyde Cross-linked Bovine Pericardium

학위논문 (석사)-- 서울대학교 대학원 : 의학과, 2012. 2. 김용진.Objectives: Decellularization is known to decrease antigenicity of xenogenic tissue, which leads to decreased calcification. But this process can alter tissue structure and cause change in physicomechanical properties and integrity of the prosthesis. This study was performed to investigate the effects of decellularization and polyethylene glycol pretreatment on physicomechanical properties and anticalcification of glutaraldehyde cross-linked bovine pericardium. Methods: As control group, bovine pericardium underwent cross-linking using glutaraldehyde, ethanol with octanol, and glycine. There were three case groups which underwent the cross-linking process following various combination of decellularization and polyethylene pretreatment. We measured tensile strength, permeability, and compliance of the prostheses to evaluate physicomechanical properties. We implanted these tissue prostheses in subcutaneous spaces of 4-week old rats, harvested the prostheses two months after the implantation, then measured the quantity of calcium formed on the prosthesis. And additionally, we evaluated the effect of α-Galactosidase pretreatment on xenogenic antigen formation. Results: Polyethylene glycol pretreatment after decellularization decreased tensile strength of the tissue prostheses, whice could be affected by increased thickness of the prostheses after multiple pretreatment processes. Decellularization increased permeability and compliance of the prostheses, but after polyethylene glycol pretreatment there was no difference of permeability and compliance compared to control group. Decellularization and polyethylene pretreatment did not reveal significant anticalcification effect. α- 3 2 galactosidase pretreatment did not precipitate increase of anti-α-Gal IgM and IgG antibodies. Conclusion: Decellularization did not affect tensile strength of bovine pericardium, but increased permeability and compliance. Polyethylene glycol pretreatment following decellularization decreased tensile strength of bovine pericardium, but maintained permeability and compliance without increase. Decellularization and polyethylene glycol pretreatment did not reveal significant anticalcification effect. More investigations for various pretreatment methods and anticalcification methods are needed to improve long-term integrity of the tissue prostheses.배경 및 연구목적: 무세포화는 조직편의 항원성을 감소시켜 석회화변성을 감소시킨다고 알려진 방법 중 하나이지만 무세포화 과정중 조직의 치밀도를 감소시켜 물리-역학적 성질을 변화시키거나 내구성에 영향을 끼칠 수 있다. 본 연구에서는 cross-linking 전에 무세포화과정중 형성된 공간을 채워줄 수 있는 space-filler인 polyethylene glycol(PEG)이 이식 조직편의 물리-역학적 특성과 석회화에 끼치는 영향에 대해서 연구해보고자 하였다. 방법: Glutaraldehyde, ethanol과 octanol, glycine detoxification으로 cross-linking처리만 시행한 군과 무세포화, polytethylene glycol 처리후 cross-linking을 조합하여 처리한 3 개의 군을 대상으로 하여 장력, 투과도, 유순도를 검사하여 물리역학적 특성을 검사하고, 생후 4주령의 쥐의 피하에 각 조직편을 이식하여 2개월 후 수거한 뒤 병리조직학적 소견을 관찰하고 칼슘을 정량적으로 측정하여 석회화의 정도를 비교하였다. 그리고, α-Galactosidase 처리가 이종 항체 형성에 영향을 주는지 관찰하고자 하였다. 결과: 무세포화 후 polyethylene glycol 처리는 심낭편의 장력을 감소시켰으나, 이는 여러 처리 후 증가된 두께에 기인할 것으로 생각된다. 무세포화 후 조직의 투과도 및 유순도는 대조군에 비해 증가하였으나, 무세포화 후 polyethylene glycol 처리를 한 경우에는 대조군과 차이가 없어 향상된 소견을 나타냈다. 무세포화 및 polyethylene glycol 처리는 석회화 5 의 감소를 보이나 대조군보다 유의한 항석회화효과는 없었다. α-galactosidase 처리후 측정한 혈중 anti-α-galactose IgM과 IgG의 변화는 보이지 않았다. 결론: 무세포화는 이식편의 장력을 감소시키지 않았으나 투과도와 유순도는 증가시켰다. 무세포화 후의 polyethylene glycol space-filler처리는 조직의 장력은 감소시켰으나 투과도 및 유순도를 유지시킬 수 있었다. 무세포화 및 polyethylene glycol 처리는 유의한 항석화 효과를 보이지 않았다. 이식 조직편의 장기 내구성을 향상시키기 위하여 앞으로 여러 방법의 조직보존 및 항석회화에 대한 연구가 필요할 것으로 생각된다.Maste

Is Hypertrophic or Keloid Wound Scar a Risk Factor for Stricture at Esophagogastric Anastomosis Site after Esophageal Cancer Operation?

Background/Aims: Anastomotic stricture at the esophagus and the conduit anastomosis site after the surgical resection of esophageal cancer is relatively common. This study examined whether a hypertrophic scar or keloid formation at a surgical wound is related to an anastomotic stricture. Methods: From March 2007 to July 2017, 59 patients underwent curative surgery for esophageal cancer. In 38 patients, end-to-end anastomosis (EEA) of the esophagus and the conduit was performed using EEA 25 mm. A hypertrophic wound scar was defined when the width of the midline laparotomy wound scar exceeded 2 mm. The relationship between the hypertrophic scar and stricture and the other risk factors for anastomotic stricture in these 38 patients was analyzed. Results: Of the 38 patients, eight patients (21.1%) had an anastomotic stricture, and a hypertrophic skin scar was observed in 14 patients (36.8%). Univariate analysis revealed lower BMI and hypertrophic scars as risk factors (p=0.032, p=0.001 respectively). Multivariate analysis revealed a hypertrophic scar as an independent risk factor for an anastomotic stricture (p=0.010, OR=27.06, 95% CI 2.19-334.40). Conclusions: Hypertrophic wound scars can be a risk factor for anastomotic stricture after surgery for esophageal cancer. An earlier prediction of anastomotic stricture by detecting hypertrophic wound healing in patients undergoing esophagectomy may improve the patients' quality of life and surgical outcomes by earlier treatments.N