title: Peritoneal Tumorigenesis and Inflammation are Ameliorated by Humidified-Warm Carbon Dioxide Insufflation in the Mouse.
abstract: BACKGROUND
  Conventional laparoscopic surgery uses CO2 that is dry and cold, which can damage peritoneal surfaces. It is speculated that disseminated cancer cells may adhere to such damaged peritoneum and metastasize. We hypothesized that insufflation using humidified-warm CO2, which has been shown to reduce mesothelial damage, will also ameliorate peritoneal inflammation and tumor cell implantation compared to conventional dry-cold CO2.
  
  
  METHODS
  Laparoscopic insufflation was modeled in mice along with anesthesia and ventilation. Entry and exit ports were introduced to maintain insufflation using dry-cold or humidified-warm CO2 with a constant flow and pressure for 1 h; then 1000 or 1 million fluorescent-tagged murine colorectal cancer cells (CT26) were delivered into the peritoneal cavity. The peritoneum was collected at intervals up to 10 days after the procedure to measure inflammation, mesothelial damage, and tumor burden using fluorescent detection, immunohistochemistry, and scanning electron microscopy.
  
  
  RESULTS
  Rapid temperature control was achieved only in the humidified-warm group. Port-site tumors were present in all mice. At 10 days, significantly fewer tumors on the peritoneum were counted in mice insufflated with humidified-warm compared to dry-cold CO2 (p < 0.03). The inflammatory marker COX-2 was significantly increased in the dry-cold compared to the humidified-warm cohort (p < 0.01), while VEGFA expression was suppressed only in the humidified-warm cohort. Significantly less mesothelial damage and tumor cell implantation was evident from 2 h after the procedure in the humidified-warm cohort.
  
  
  CONCLUSIONS
  Mesothelial cell damage and inflammation are reduced by using humidified-warm CO2 for laparoscopic oncologic surgery and may translate to reduce patients' risk of developing peritoneal metastasis.
authors: Cancer Research Division, Peter MacCallum Cancer Centre, Melbourne, VIC, Australia.
authors: Sandra
authors: S
authors: Carpinteri
authors: Cancer Research Division, Peter MacCallum Cancer Centre, Melbourne, VIC, Australia.
authors: Shienny
authors: S
authors: Sampurno
authors: Cancer Research Division, Peter MacCallum Cancer Centre, Melbourne, VIC, Australia.|Department of Surgical Oncology, Peter MacCallum Cancer Centre, Melbourne, VIC, Australia.
authors: Maria-Pia
authors: MP
authors: Bernardi
authors: Cancer Research Division, Peter MacCallum Cancer Centre, Melbourne, VIC, Australia.
authors: Markus
authors: M
authors: Germann
authors: Cancer Research Division, Peter MacCallum Cancer Centre, Melbourne, VIC, Australia.
authors: Jordane
authors: J
authors: Malaterre
authors: Department of Surgical Oncology, Peter MacCallum Cancer Centre, Melbourne, VIC, Australia.
authors: Alexander
authors: A
authors: Heriot
authors: Faculty of Veterinary Science, University of Melbourne, Parkville, VIC, Australia.
authors: Brenton A
authors: BA
authors: Chambers
authors: Lung Institute of Western Australia and Centre for Cell Therapy and Regenerative Medicine, Nedlands, WA, Australia.
authors: Steven E
authors: SE
authors: Mutsaers
authors: Department of Surgical Oncology, Peter MacCallum Cancer Centre, Melbourne, VIC, Australia.
authors: Andrew C
authors: AC
authors: Lynch
authors: Peter MacCallum Cancer Centre, Sir Peter MacCallum Department of Oncology, The University of Melbourne, Melbourne, VIC, Australia. rob.ramsay@petermac.org.
authors: Robert G
authors: RG
authors: Ramsay
mesh_terms: D000818:Animals; D002245:Carbon Dioxide / Q000008:administration & dosage / Q000494:pharmacology*; D002471:Cell Transformation, Neoplastic / Q000187:drug effects* / Q000473:pathology; D005260:Female; D006358:Hot Temperature; D006813:Humidity; D007249:Inflammation / Q000503:physiopathology / Q000517:prevention & control*; D007327:Insufflation / Q000379:methods*; D051379:Mice; D008807:Mice, Inbred BALB C; D010534:Peritoneal Neoplasms / Q000503:physiopathology / Q000517:prevention & control*; D010537:Peritoneum / Q000187:drug effects* / Q000293:injuries / Q000473:pathology; D014407:Tumor Cells, Cultured
chemical_list: D002245:Carbon Dioxide