Different contribution of substrates oxidation to insulin resistance in malnourished elderly patients with cancer.
BACKGROUND
The relative contribution of malnutrition and cancer to insulin resistance in elderly patients is still poorly understood.


METHODS
Twenty malnourished and 15 well-nourished patients with cancer matched for age (70 +/- 0.3 versus 69 +/- 0.3 years; P = not significant), mean arterial blood pressure (104 +/- 8 versus 107 +/- 7 mm Hg; P = not significant), gender ratio (10 males/10 females versus 7 males/8 females), and sedentary life style underwent an euglycemic glucose clamp. Simultaneous infusion of 3-D-H-glucose and indirect calorimetry allowed the authors to determine glucose turnover parameters and analyze substrates oxidation.


RESULTS
Malnourished patients displayed a reduced total body glucose metabolism (36 +/- 2 versus 31 +/- 3 mumol/kg of lean body mass x min P < 0.04) despite higher glucose oxidation. In the same group of patients, the authors demonstrated a significant increase in lipid oxidation and the lack of the inverse relationship between glucose and lipid oxidation (r = 0.07; P = not significant). Insulin infusion enhanced glucose oxidation and suppressed lipid oxidation, but such changes were at lower extent in malnourished patients.


CONCLUSIONS
Our study confirms the presence of insulin resistance in malnourished patients and demonstrates the relative contribution of substrates oxidation to the insulin resistance itself.
Gambardella
A
A
Department of Geriatric Medicine, Medical School, II University of Naples, Italy.
Paolisso
G
G
D'Amore
A
A
Granato
M
M
Verza
M
M
Varricchio
M
M
D000368:Aged; D016009:Chi-Square Distribution; D004734:Energy Metabolism; D005260:Female; D005947:Glucose / Q000378:metabolism*; D006801:Humans; D007333:Insulin Resistance; D050356:Lipid Metabolism; D008297:Male; D009369:Neoplasms / Q000150:complications / Q000378:metabolism*; D009748:Nutrition Disorders / Q000209:etiology / Q000378:metabolism*; D010084:Oxidation-Reduction; D011506:Proteins / Q000378:metabolism*
D011506:Proteins; D005947:Glucose