title: An LED light source and novel fluorophore combinations improve fluorescence laparoscopic detection of metastatic pancreatic cancer in orthotopic mouse models.
abstract: BACKGROUND
  The aim of this study was to improve fluorescence laparoscopy of pancreatic cancer in an orthotopic mouse model with the use of a light-emitting diode (LED) light source and optimal fluorophore combinations.
  
  
  METHODS
  Human pancreatic cancer models were established with fluorescent FG-RFP, MiaPaca2-GFP, BxPC-3-RFP, and BxPC-3 cancer cells implanted in 6-week-old female athymic mice. Two weeks postimplantation, diagnostic laparoscopy was performed with a Stryker L9000 LED light source or a Stryker X8000 xenon light source 24 hours after tail-vein injection of CEA antibodies conjugated with Alexa 488 or Alexa 555. Cancer lesions were detected and localized under each light mode. Intravital images were also obtained with the OV-100 Olympus and Maestro CRI Small Animal Imaging Systems, serving as a positive control. Tumors were collected for histologic analysis.
  
  
  RESULTS
  Fluorescence laparoscopy with a 495-nm emission filter and an LED light source enabled real-time visualization of the fluorescence-labeled tumor deposits in the peritoneal cavity. The simultaneous use of different fluorophores (Alexa 488 and Alexa 555), conjugated to antibodies, brightened the fluorescence signal, enhancing detection of submillimeter lesions without compromising background illumination. Adjustments to the LED light source permitted simultaneous detection of tumor lesions of different fluorescent colors and surrounding structures with minimal autofluorescence.
  
  
  CONCLUSIONS
  Using an LED light source with adjustments to the red, blue, and green wavelengths, it is possible to simultaneously identify tumor metastases expressing fluorescent proteins of different wavelengths, which greatly enhanced the signal without compromising background illumination. Development of this fluorescence laparoscopy technology for clinical use can improve staging and resection of pancreatic cancer.
authors.affiliation: Department of Surgery, University of California San Diego, La Jolla, CA 92093-0987, USA.
authors.forename: Cristina A
authors.initials: CA
authors.lastname: Metildi
authors.forename: Sharmeela
authors.initials: S
authors.lastname: Kaushal
authors.forename: Claudia
authors.initials: C
authors.lastname: Lee
authors.forename: Chanae R
authors.initials: CR
authors.lastname: Hardamon
authors.forename: Cynthia S
authors.initials: CS
authors.lastname: Snyder
authors.forename: George A
authors.initials: GA
authors.lastname: Luiken
authors.forename: Mark A
authors.initials: MA
authors.lastname: Talamini
authors.forename: Robert M
authors.initials: RM
authors.lastname: Hoffman
authors.forename: Michael
authors.initials: M
authors.lastname: Bouvet
mesh_terms: D000818:Animals; D004867:Equipment Design; D005260:Female; D005453:Fluorescence; D005456:Fluorescent Dyes; D006801:Humans; D010535:Laparoscopy / Q000379:methods*; D008029:Lighting / Q000295:instrumentation*; D051379:Mice; D008819:Mice, Nude; D009368:Neoplasm Transplantation; D009374:Neoplasms, Experimental / Q000175:diagnosis* / Q000556:secondary; D010190:Pancreatic Neoplasms / Q000175:diagnosis* / Q000556:secondary; D015203:Reproducibility of Results; D014407:Tumor Cells, Cultured / Q000637:transplantation
chemical_list: D005456:Fluorescent Dyes