Peritoneal Tumorigenesis and Inflammation are Ameliorated by Humidified-Warm Carbon Dioxide Insufflation in the Mouse

Abstract

BackgroundConventional 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.MethodsLaparoscopic 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.ResultsRapid 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.ConclusionsMesothelial 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.Electronic supplementary materialThe online version of this article (doi:10.1245/s10434-015-4508-1) contains supplementary material, which is available to authorized users.

Changes in the coelomic microclimate during carbon dioxide laparoscopy: morphological and functional implications

“…Using a more proportionate insufflation IPP of 5 mmHg and CO 2 flow rate of 50 mL/min in rats and 2 mmHg and 14-52 mL/min in mice, with routine ETT intubation and pulmonary ventilation, control for these changes. This allows for more reproducible experimental conditions and reliable studies [13,18,42,43]. The absorption of CO 2 is also related to excess IPP.…”

“…The ECM is made up of the BM and submesothelial layer with a reservoir of signalling molecules. These respond to ECM exposure or secreted growth factors such as fibroblast growth factor (FGF) [4,5,18]. The peritoneal integrins are comprised of an α (α 2 , α 3 , α 5 , α 6 , or α v ) and β (β 1 or β 3 ) subunit combination.…”

“…Loss of the tribologic properties of the peritoneal fluid impairs its lubricating ability and its normal fibrinolytic and inflammatory responses. This can result in greater postoperative adhesion formation, prolonged recovery, ileus, shoulder tip/subdiaphragmatic pain and potentially tumour cell adhesiveness [2,5,[18][19][20].…”

“…Ott (2003) introduced the concept of the 'desertification' of the peritoneum due to surface evaporation and desiccation with the use of dry CO 2 [2]. With cold-dry CO 2 -pneumoperitoneum under SEM, drastic alterations of the peritoneal surface layer are seen, with microvilli loss, extreme desquamation of mesothelial cells, and obvious exposure of the basal membrane [13,18,29] (see Figure 1). In a fully water saturated CO 2 pneumoperitoneum (relative humidity 100 %) with a temperature similar to the surrounding tissues of 37°C, no further evaporation from the peritoneal serous layer can occur [5].…”

“…Local effects include peritoneal and splanchnic hypoperfusion, peritoneal ischaemia and reperfusion injury, immunological and oxidative stress response disturbances, spread of tumour cells and bacterial translocation [2,5,18]. Systemic pulmonary effects include atelectasis, Alveolar arterial (Aa) O 2 mismatch and decreased pulmonary tidal volume/functional residual capacity/vital capacity and pulmonary compliance.…”