Enlargement of the indication of endoscopic resection for superficial type early colorectal carcinomas using functional magnet cationic liposomes

2004 Fiscal Year Final Research Report Summary

• Project/Area Number: 15590611
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Gastroenterology
• Research Institution: Asahikawa Medical College
• Principal Investigator: SAITOH Yusuke Asahikawa Medical College, Third Department of Internal Medicine, Associate Professor, 医学部, 助教授 (30281900)
• Co-Investigator(Kenkyū-buntansha): WATARI Jiro Asahikawa Medical College, Third Dept.of Int.Med., Instructor, 医学部, 助手 (10311531) ; KOHGO Yutaka Asahikawa Medical College, Third Dept.of Int.Med., Professor, 医学部, 教授 (10133183)
• Project Period (FY): 2003 – 2004
• Keywords: colorectal submucosal tumors / Magnetite cationic liposome / cancer ablation therapy / 超音波内視鏡 / リンパ節転移 / 温熱療法

Research Abstract

Aim : The aim of this study was to enlarge the indication of endoscopic therapy for submucosal colorectal carcinomas which has been indicated for surgical resection and pilot experiment was planned. Non-surgical ablation therapy (heat therapy) may be developed by the following steps. i)Magnet cationic liposomes (MCL) was made in which contain functional nano-sized magnet (about 80nm in size) for the lymphnodes as a biotarget. ii)MCL was injected into the submuocosal layer using endoscopic ultrasonography as a delivery system and was deliverd to the regional lymphnodes. iii)After MCL was accumulated in the lymphnodes, microwave was irradiated and MCL generate heat kill the metastic cancer cells in the regional lymphnodes.
Method : MCL was made according to the same methods reported by Yanase, et al. (Jpn J Cancer Res 89,1998). After abdominal surgery was performed under anesthesia for 13 weeks after birth Wiste rats (body weight were about 300g), 0.1ml of MCL (Magnetite 1.7mg/ml) was inj ected into the rectal wall. Histopathological findings (macroscopic and microscopic findings) and the findings of ultrasonogrraphic findings (Fujinon SP701, 20 MHz was used) were compared after 2 and 24 hours after injection.
Results : It was histopathologically revealed in the reseated specimens after 2 hours at the injected site of the rectum that submucosal lymphocytes aggregation was shown mainly in the submucosal layer and MCL was also demonstrated by ferrous stain. The same sites were visualized as high echo spots by ultrasonography. Moreover, MCL were also detected as blue by ferrous stain in the near lymphnodes and distally located lymphnodes as well. MCL was detected in the medullary sinus and the germinal center of the regional lymphnodes and in the marginal sinus of the distally located lymphnode from the injected site. Lymphnodes were visualized by ultrasonography as high echo areas which mixed high echo spots with acoustic shadow.
Prospects in the future : We will develop another new contrast media which have more cancer affinity than MCL and aim at clinical practice of cancer ablation methods as a heat therapy.