title: Randomized clinical trial to compare the effects of preoperative oral carbohydrate versus placebo on insulin resistance after colorectal surgery.
abstract: BACKGROUND
  Preoperative oral carbohydrate (OCH) reduces postoperative insulin resistance (PIR). This randomized trial investigated whether this effect is related to insulin-induced activation of the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (PKB) signalling pathway.
  
  
  METHODS
  Patients with colorectal cancer scheduled for elective open resection were randomly assigned to preoperative OCH, fasting or placebo. Preoperative general well-being, insulin resistance before and immediately after surgery, and postoperative expression of PI3K, PKB, protein tyrosine kinase (PTK) and glucose transporter 4 (GLUT4) in rectus abdominis muscle were evaluated.
  
  
  RESULTS
  Patient and operative characteristics did not differ between groups. Subjective well-being was significantly better in OCH and placebo groups than in the fasting group, primarily because of reduced thirst (P = 0.005) and hunger (P = 0.041). PIR was significantly greater in fasting and placebo groups (P < 0.010). By the end of surgery, muscle PTK activity as well as PI3K and PKB levels were significantly increased in the OCH group compared with values in fasting and placebo groups (P < 0.050), but GLUT4 expression was unaffected.
  
  
  CONCLUSIONS
  PIR involves the PI3K/PKB signalling pathway. Preoperative OCH intake improves preoperative subjective feelings of hunger and thirst compared with fasting, while attenuating PIR by stimulation of the PI3K/PKB pathway.
authors.affiliation: Department of General Surgery, Shanghai Chang Zheng Hospital, Second Military Medical University, Shanghai, China.
authors.forename: Z G
authors.initials: ZG
authors.lastname: Wang
authors.forename: Q
authors.initials: Q
authors.lastname: Wang
authors.forename: W J
authors.initials: WJ
authors.lastname: Wang
authors.forename: H L
authors.initials: HL
authors.lastname: Qin
mesh_terms: D000284:Administration, Oral; D000368:Aged; D001786:Blood Glucose / Q000378:metabolism; D015153:Blotting, Western; D002241:Carbohydrates / Q000008:administration & dosage*; D015179:Colorectal Neoplasms / Q000601:surgery*; D005215:Fasting / Q000378:metabolism; D005260:Female; D051275:Glucose Transporter Type 4 / Q000378:metabolism; D006801:Humans; D007328:Insulin / Q000502:physiology*; D007333:Insulin Resistance / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D011300:Preoperative Care / Q000379:methods; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism*
chemical_list: D001786:Blood Glucose; D002241:Carbohydrates; D051275:Glucose Transporter Type 4; D007328:Insulin; C495692:SLC2A4 protein, human; D019869:Phosphatidylinositol 3-Kinases; D051057:Proto-Oncogene Proteins c-akt