Association between omental adipose tissue macrophages and liver histopathology in morbid obesity: Influence of glycemic status

Background/Aims: Recently we showed that macrophage accumulation in omental adipose tissue is associated with liver fibro-inflammation in morbidly obese subjects. Here, we evaluated the influence of glycemic status and extended the analysis to the spectrum of obesity-linked liver damage. Methods: Liver biopsies, subcutaneous and omental adipose tissue were collected in 132 obese subjects during gastric bypass surgery. HAM56+ adipose tissue macrophages were counted in subjects classified by liver histopathology and by their degree of insulin resistance. Results: In the whole population, the number of omental macrophages increased with the score of steatosis, the non-alcoholic fatty liver disease activity score, the stage of fibrosis and with fibro-inflammation index. None of these relationships were significant with subcutaneous macrophage count. In insulin-sensitive participants, omental macrophages accumulation was higher in subjects with high indexes of fibro-inflammation (p = 0.012 vs. low indexes). In insulin-resistant including type 2 diabetic participants, omental macrophage count was higher both in subjects with high scores of steatosis and in subjects with high indexes of fibro-inflammation (p < 0.05 vs. low scores). Conclusions: Macrophage accumulation in omental adipose tissue is associated with aggravated steatosis and fibro-inflammation in insulin-resistant obese subjects independently of altered glycemic status. (C) 2009 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.