title: Does thermodynamic stability of peritoneal collagen change during laparoscopic cholecystectomies? A differential scanning calorimetry (DSC) study.
abstract: BACKGROUND
  Carbon dioxide pneumoperitoneum used during laparoscopic surgeries alters the integrity of the peritoneum and results in denudation of the basal lamina that might cause altered immune response, inhibited fibrinolysis, hypoxia, and acidosis. The changes in the structure of pneumoperitoneum were described as bulging of mesothelial cells, irregular cell junction's cell membrane degradation, and mesodermal edema. As denaturation of peritoneal proteins reflects overall condition of its structure and interactions with the surrounding molecules, the physical status of collagen was assessed on the basis of parameters of thermal denaturation measured by DSC method.
  
  
  METHODS
  Twenty-four female patients operated on due to cholelithiasis were enrolled in this study. Laparoscopic cholecystectomy was performed using standard four-trocar technique, and standard values of insufflated carbon dioxide pneumoperitoneum were used. After trocar placement, the first collection of peritoneal sample (sample A) was performed. The second peritoneal sample (sample B) was collected after the removal of gall bladder. Differential scanning calorimetry (Q200 calorimeter, TA Instruments) was performed on samples defrosted at room temperature.
  
  
  RESULTS
  In all samples of peritoneum, a nonreversible endothermal process recognized as denaturation was observed. Sample B obtained at the end of surgery did not differ from sample A obtained at the beginning in terms of all parameters under study. Temperature of denaturation in A and B was correlated only marginally, but enthalpy and specific heat were significantly correlated. The analysis of data from DSC measurements did not reveal differences in physical stability of collagen in peritoneal samples obtained at the beginning and at the end of surgery. Significant negative correlations between duration of CO2 pneumoperitoneum and enthalpy of denaturation in sample B were found.
  
  
  CONCLUSIONS
  Differences in enthalpy of denaturation may reflect a quantitative relation between amount of native collagen molecules in the sample and other, non-collagenous components or impaired collagen.
authors.affiliation: Human Anatomy Department, Laboratory of Medical Simulation, Medical University of Lublin, Jaczewskiego 4, 20-094, Lublin, Poland, kamiltorres@wp.pl.
authors.forename: Kamil
authors.initials: K
authors.lastname: Torres
authors.forename: Hanna
authors.initials: H
authors.lastname: Trębacz
authors.forename: Magdalena
authors.initials: M
authors.lastname: Bącik-Donica
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Atras
authors.forename: Anna
authors.initials: A
authors.lastname: Torres
authors.forename: Zbigniew
authors.initials: Z
authors.lastname: Plewa
mesh_terms: D002152:Calorimetry, Differential Scanning / Q000379:methods*; D002245:Carbon Dioxide / Q000008:administration & dosage; D017081:Cholecystectomy, Laparoscopic / Q000379:methods*; D002769:Cholelithiasis / Q000601:surgery*; D003094:Collagen / Q000378:metabolism*; D004847:Epithelial Cells / Q000378:metabolism; D005260:Female; D005342:Fibrinolysis / Q000502:physiology; D006801:Humans; D007327:Insufflation / Q000379:methods; D010537:Peritoneum / Q000378:metabolism; D013696:Temperature; D013816:Thermodynamics
chemical_list: D002245:Carbon Dioxide; D003094:Collagen