Is obesity an inflammatory disease?
BACKGROUND
Most obese individuals have elevated concentrations of interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha), markers of inflammation closely associated with diabetes, hypertension, and stroke.


OBJECTIVE
Obesity is a low-grade inflammatory disease, and Roux-en-Y gastric bypass (RYGB) reduces biochemical markers of inflammation and modifies gene expression in hypothalamic food intake/energy-related nuclei and subcutaneous abdominal fat (SAF).


METHODS
Obesity was induced in 24 3-week-old Sprague Dawley pups fed a high-energy diet (HED). Three groups (n = 8/group) were studied: RYGB, sham-operated pair-fed, and sham-operated ad libitum HED. Controls were nonobese rats fed chow (n = 6). Rats were killed 10 days after operation, and blood was collected to measure corticosterone and SAF and mesenteric fat to measure IL-6, TNF-alpha, and corticosterone. Total mRNA from arcuate nucleus and SAF purified for gene expression profiling. Data were analyzed with analysis of variance, Mann-Whitney test, and t test.


RESULTS
Before operation, the body weight of the obese groups was 493 +/- 7 g and control = 394 +/- 12g. The 10-day postoperative weight was RYGB = 417 +/- 21 g, pair-fed = 436 +/- 14 g, and ad libitum HED = 484 +/- 15 g. Mesenteric and SAF weight decreased in RYGB. Mesenteric/SAF ratio of IL-6, TNF-alpha, corticosterone, and gene profiling showed decrease of inflammation after RYGB.


CONCLUSIONS
Gastric bypass reduces biochemical markers of inflammation, suggesting that obesity is an inflammatory condition.
Ramos
Eduardo J B
EJ
Department of Surgery, Management Information and Decision, Clinical Molecular Medicine, SUNY Upstate Medical University, Syracuse University, Syracuse, NY, USA.
Xu
Yuan
Y
Romanova
Irina
I
Middleton
Frank
F
Chen
Chung
C
Quinn
Robert
R
Inui
Akio
A
Das
Undurti
U
Meguid
Michael M
MM
D000273:Adipose Tissue / Q000473:pathology; D000713:Anastomosis, Roux-en-Y; D000818:Animals; D015415:Biomarkers; D001835:Body Weight; D015390:Gastric Bypass; D007249:Inflammation / Q000378:metabolism / Q000503:physiopathology*; D015850:Interleukin-6 / Q000378:metabolism; D050356:Lipid Metabolism; D008297:Male; D009765:Obesity / Q000473:pathology / Q000503:physiopathology* / Q000601:surgery*; D020411:Oligonucleotide Array Sequence Analysis; D051381:Rats; D017207:Rats, Sprague-Dawley; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
D015415:Biomarkers; D015850:Interleukin-6; D014409:Tumor Necrosis Factor-alpha