The aim of the study is to investigate whether preoperative interventions such as carbohydrate drinks, Dichloroacetate and exercise would inhibit or reverse the changes in molecular mechanisms regulating muscle carbohydrate oxidation and postoperative muscle insulin resistance in patients undergoing major abdominal surgery.
Forty patients undergoing open elective gastrointestinal surgery, will be randomized to four groups of 10 each. The patients will be randomised to receive either preoperative (1) oral carbohydrate drinks (CHO) or (2) infusion of Dichloroacetate with oral carbohydrate drinks (3) exercise or (4) standard care. Since the interventions are qualitatively different and only the physiological mechanisms are being studied rather than the clinical outcomes, the study is not blinded and no placebo is used. Analysis for cytokines, insulin, glucagon levels will be performed at screening, during surgery and on the 2nd postoperative day. Muscle biopsies will be taken at the beginning and end of surgery, from rectus abdominus and vastus lateralis muscles for analysis of mRNA (IL-6, TNF-α, Akt1, IRS-1, FOXO1, MAFbx, MURF1 and PDK4) and protein (MafBx, FOXO1, PDK4) expression and muscle metabolites (glycogen, lactate, triglycerides and FFA). Oral Glucose Tolerance Test (GTT) to be performed at the screening visit and on the 2nd postoperative day using a standard protocol. The techniques to be employed to study the above will include RT-PCR, radioimmunoassay, spectophotometry, bioluminometry, Western blotting and ELISA. Primary outcome: The changes in indices of muscle insulin resistance and muscle protein breakdown at the beginning and at the end of surgery, in response to surgical stress. Secondary outcomes: (a) The expression of muscle metabolites, reflecting muscle protein turnover (b) Clinical Outcomes: Length of stay and incidence of postoperative complications.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
NONE
Enrollment
40
Dichloroacetate, an analog of acetic acid has been shown to increase the activation of PDC by inhibiting PDK4 in humans. This drug is expected to shift the metabolism of pyruvate from glycolysis and towards oxidative pathway in the mitochondria
preoperative carbohydrate drinks
30 min exercise using a semi-recumbent exercise bike, at about 70% of their age estimated heart rate
University Hospitals Nottingham Queen's Medical Centre
Nottingham, Nottingham, United Kingdom
insulin resistance
Relative changes in indices of muscle insulin resistance namely PDC activity, PDK4 mRNA and protein expression.
Time frame: 48 hours after surgery
muscle carbohydrate oxidation
Changes in muscle metabolites such as glycogen, glucose, lactate, reflecting the changes in skeletal muscle carbohydrate oxidation.
Time frame: 48 hours after surgery
Mitochondrial ATP production
Mitochondrial ATP production rates in patients undergoing major abdominal surgery.
Time frame: 48 hours after surgery
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