Randomized clinical trial to compare the effects of preoperative oral carbohydrate versus placebo on insulin resistance after colorectal surgery.
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.
Wang
Z G
ZG
Department of General Surgery, Shanghai Chang Zheng Hospital, Second Military Medical University, Shanghai, China.
Wang
Q
Q
Wang
W J
WJ
Qin
H L
HL
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*
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