title: A novel approach of optical biopsy using probe-based confocal laser endomicroscopy for peritoneal metastasis.
abstract: In digestive cancers, it is mandatory to diagnose peritoneal metastasis prior to selecting therapy. Therefore, exploratory laparoscopy has gained wider clinical acceptance. In laparoscopy, the peritoneal metastasis is pathologically confirmed by excisional biopsy; however, there remain technical difficulties in performing precise diagnosis and adequate biopsy on small peritoneal lesions without damaging organs. We have focused on "optical biopsy" using probe-based confocal laser endomicroscopy (pCLE). The aims of this study were (1) to optimize current CLE system for real-time observation of peritoneal metastases and (2) to assess its potential usefulness as diagnostic modality in preclinical settings.
  
  
  
  To optimize condition and evaluate feasibility, we prepared peritoneal metastasis mice model with gastric cancer cell line (MKN-45). On Day 10 after seeding, the mice were laparotomized and performed pCLE observations with CellvizioLAB (LSU-F 400/488 nm, Mauna Kea Technologies, Paris, France). We evaluated two different CLE probes, three different dyes, and optimal interval time. The detected sites were excised and pathologically evaluated on its morphology. Next, the feasibility and safety were validated in porcine model for clinical usage. After injection of fluorescein, pCLE was applied for the observation of intra-abdominal organs.
  
  
  
  A miniature probe-type pCLE system with 60 μm focal depth (UltraMini O) and 1 % fluorescein dye was chosen for good visualization in mice model. The irregular microarchitecture images suspected to malignancy were obtained from the metastases. In the porcine model, observation of abdominal organs was feasible without any organ injury in the laparoscopic procedures. The dosage of 1 % fluorescein (3 ml/body) was appropriate in observing intra-abdominal organs, and each intra-abdominal organ was clearly observed with the same imaging quality we obtained in mice model.
  
  
  
  The pCLE was feasible and safe and potentially useful for the diagnosis of the peritoneal metastasis in in vivo animal models.
authors.affiliation: Department of Gastroenterological Surgery, Osaka University Graduate School of Medicine, Suita, Japan.|Laboratory for Immune Signal, National Institute of Biomedical Innovation, Health and Nutrition, Ibaraki, Japan.
authors.forename: Hisashi
authors.initials: H
authors.lastname: Hara
authors.affiliation: Department of Gastroenterological Surgery, Osaka University Graduate School of Medicine, Suita, Japan.|Laboratory for Immune Signal, National Institute of Biomedical Innovation, Health and Nutrition, Ibaraki, Japan.
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Takahashi
authors.affiliation: Department of Gastroenterological Surgery, Osaka University Graduate School of Medicine, Suita, Japan.|Laboratory for Immune Signal, National Institute of Biomedical Innovation, Health and Nutrition, Ibaraki, Japan.
authors.forename: Rie
authors.initials: R
authors.lastname: Nakatsuka
authors.affiliation: Department of Gastroenterological Surgery, Osaka University Graduate School of Medicine, Suita, Japan.|Division of Next Generation Endoscopic Intervention, Osaka University, Suite 0912, Center of Medical Innovation and Translational Research, 2-2, Yamadaoka, Suita, Osaka, 565-0871, Japan.
authors.forename: Shigeyoshi
authors.initials: S
authors.lastname: Higashi
authors.affiliation: Laboratory for Immune Signal, National Institute of Biomedical Innovation, Health and Nutrition, Ibaraki, Japan.
authors.forename: Tetsuji
authors.initials: T
authors.lastname: Naka
authors.affiliation: Department of Endoscopy, The Jikei University School of Medicine, Tokyo, Japan.
authors.forename: Kazuki
authors.initials: K
authors.lastname: Sumiyama
authors.affiliation: Department of Gastroenterological Surgery, Osaka University Graduate School of Medicine, Suita, Japan.
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Miyazaki
authors.affiliation: Department of Gastroenterological Surgery, Osaka University Graduate School of Medicine, Suita, Japan.
authors.forename: Tomoki
authors.initials: T
authors.lastname: Makino
authors.affiliation: Department of Gastroenterological Surgery, Osaka University Graduate School of Medicine, Suita, Japan.
authors.forename: Yukinori
authors.initials: Y
authors.lastname: Kurokawa
authors.affiliation: Department of Gastroenterological Surgery, Osaka University Graduate School of Medicine, Suita, Japan.
authors.forename: Makoto
authors.initials: M
authors.lastname: Yamasaki
authors.affiliation: Department of Gastroenterological Surgery, Osaka University Graduate School of Medicine, Suita, Japan.
authors.forename: Shuji
authors.initials: S
authors.lastname: Takiguchi
authors.affiliation: Department of Gastroenterological Surgery, Osaka University Graduate School of Medicine, Suita, Japan.
authors.forename: Masaki
authors.initials: M
authors.lastname: Mori
authors.affiliation: Department of Gastroenterological Surgery, Osaka University Graduate School of Medicine, Suita, Japan.
authors.forename: Yuichiro
authors.initials: Y
authors.lastname: Doki
authors.affiliation: Department of Gastroenterological Surgery, Osaka University Graduate School of Medicine, Suita, Japan. knakajima@gesurg.med.osaka-u.ac.jp.|Division of Next Generation Endoscopic Intervention, Osaka University, Suite 0912, Center of Medical Innovation and Translational Research, 2-2, Yamadaoka, Suita, Osaka, 565-0871, Japan. knakajima@gesurg.med.osaka-u.ac.jp.
authors.forename: Kiyokazu
authors.initials: K
authors.lastname: Nakajima
mesh_terms: D034841:Abdominal Cavity / Q000000981:diagnostic imaging* / Q000473:pathology; D000818:Animals; D001706:Biopsy; D045744:Cell Line, Tumor; D016145:Endoscopy, Digestive System / Q000379:methods*; D005240:Feasibility Studies; D019793:Fluorescein; D005456:Fluorescent Dyes; D051379:Mice; D018613:Microscopy, Confocal / Q000379:methods*; D023421:Models, Animal; D010534:Peritoneal Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D013552:Swine
chemical_list: D005456:Fluorescent Dyes; D019793:Fluorescein
keywords: 5-Aminolevulinic acid; Confocal laser endomicroscopy; Fluorescein; Optical biopsy; Peritoneal metastasis; pCLE