Association between measures of insulin sensitivity and circulating levels of interleukin-8, interleukin-6 and tumor necrosis factor-alpha. Effect of weight loss in obese men.
OBJECTIVE
To study the association between anthropometric and metabolic parameters as well as the effect of weight loss on plasma levels of the adipose tissue-derived cytokines interleukin-8 (IL-8), interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha) in abdominal obese men.


METHODS
Nineteen obese (mean body mass index (BMI): 38.6+/-0.6 kg/m(2)) and ten lean men (mean BMI: 23.4+/-0.4 kg/m(2)) were included in the study. The obese subjects received a 4.2 MJ/day diet for 8 weeks, followed by 8 weeks on energy restriction (6.2 MJ/day) and 8 weeks on a weight-maintenance diet.


METHODS
A dual energy X-ray absorptiometry (DEXA)-scan was performed to estimate body composition. Plasma levels of IL-8, IL-6 and TNF-alpha were measured by a specific ELISA method. Insulin sensitivity was assessed by the homeostasis model assessment method (HOMA).


RESULTS
Plasma levels of IL-8 and IL-6 were 30-40% higher in obese as compared with lean subjects (P<0.05), whereas no group difference in TNF-alpha was observed. During the intervention, obese subjects obtained a 30% reduction in fat mass (P<0.001), fasting insulin (P<0.05) and HOMA (P<0.05). Plasma levels of TNF-alpha and IL-6 were decreased by 25-30% (P<0.001) but IL-8 was increased by 30% (P<0.001) after weight loss. IL-8 and IL-6 were correlated with measures of insulin resistance, and changes in IL-6 but not IL-8 were correlated with the improvement in insulin sensitivity after weight loss.


CONCLUSIONS
Plasma levels of IL-8 and IL-6 were found to be increased and were correlated with measures of insulin resistance in abdominal obese male subjects. Weight loss was associated with changes in the circulating levels of IL-8, IL-6 and TNF-alpha indicating that these cytokines are influenced by weight loss.
Department of Endocrinology and Metabolism C, Aarhus Amtssygehus, Aarhus University Hospital and Faculty of Health Sciences, Aarhus University, Tage Hansensgade 2, DK-8000 Aarhus C, Denmark. jmb@mail-online.dk
Jens M
JM
Bruun
Camilla
C
Verdich
Søren
S
Toubro
Arne
A
Astrup
Bjørn
B
Richelsen
D000328:Adult; D000886:Anthropometry; D006801:Humans; D007333:Insulin Resistance / Q000502:physiology*; D015850:Interleukin-6 / Q000097:blood*; D016209:Interleukin-8 / Q000097:blood*; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000097:blood* / Q000178:diet therapy*; D013851:Thinness / Q000097:blood; D014409:Tumor Necrosis Factor-alpha / Q000032:analysis*; D015431:Weight Loss
D015850:Interleukin-6; D016209:Interleukin-8; D014409:Tumor Necrosis Factor-alpha