Effect of short-term hyperglycemia on adipose tissue fluxes of selected cytokines in vivo during multiple phases of diet-induced weight loss in obese women.
BACKGROUND
Hyperglycemia is suggested to be one of the drivers of the proinflammatory state observed in obese and diabetic patients.


OBJECTIVE
The objectives of the study was to investigate whether sc abdominal adipose tissue (scAT) could be one of the important sources of proinflammatory cytokines released in response to short-term hyperglycemia and whether this secretion capacity could be influenced by weight loss.


METHODS
Output of cytokines and proteins of acute phase from scAT in response to a 3-hours hyperglycemic clamp was evaluated in nine obese women in vivo using Fick's principle. Moreover, the output of cytokines was analyzed during a multiphase dietary intervention consisting of 1 month on a very low-calorie diet and subsequent 5-month weight-stabilization phase.


METHODS
The levels of cytokines and proteins of acute phase [IL-6, IL-8, IL-1 receptor antagonist (IL-1Ra), TNF-α, monocyte chemoattractant protein-1 (MCP-1), serum amyloid A, and C-reactive protein] in arterial and venous plasma were measured during each dietary phase. The insulin sensitivity of scAT in respect to the antilipolytic effect of insulin during the clamp was assessed.


RESULTS
Hyperglycemia increased the output of cytokines IL-6, MCP-1, and IL-1Ra from scAT. This effect had a tendency to be reduced after weight loss. The output of other proinflammatory substances from scAT into circulation was not detected. The diet-induced weight loss was associated with the improvement of antilipolytic insulin sensitivity in scAT.


CONCLUSIONS
The results suggest that short-term hyperglycemia induces an increase of the output of cytokines IL-6, IL-1Ra, and MCP-1 from adipose tissue, and this deleterious hyperglycemia effect may be attenuated by the diet-induced weight reduction. This lowered responsiveness of the inflammation-related system may be an important feature of the weight reduction-induced improvement of the metabolic status of obese prediabetic individuals.
Department of Sports Medicine (M.S., J.P., V.S.), Third Faculty of Medicine, Charles University, 100 00 Prague, Czech Republic; Department of Clinical Physiology (L.S., J.B.), Bispebjerg University Hospital, 2400 Copenhagen, Denmark; and Department of Biomedical Sciences (J.B.), University of Copenhagen, DK-1165 Copenhagen, Denmark.
Michaela
M
Siklova
Lene
L
Simonsen
Jan
J
Polak
Vladimir
V
Stich
Jens
J
Bülow
D000273:Adipose Tissue / Q000378:metabolism*; D000328:Adult; D016207:Cytokines / Q000097:blood*; D004038:Diet, Reducing; D005260:Female; D006801:Humans; D006943:Hyperglycemia / Q000378:metabolism*; D009765:Obesity / Q000178:diet therapy / Q000378:metabolism*; D015431:Weight Loss / Q000502:physiology*
D016207:Cytokines