Identification of omentin mRNA in human epicardial adipose tissue: comparison to omentin in subcutaneous, internal mammary artery periadventitial and visceral abdominal depots

Abstract

Objective: The purpose of this study was to determine the relative distribution of omentin and visfatin mRNA in human epicardial, peri-internal mammary, upper thoracic, upper abdominal and leg vein subcutaneous adipose tissue as well as the distribution of omentin in the nonfat cells and adipocytes of human omental adipose tissue. Background: Omentin is found in human omentum but not subcutaneous fat. Omentin and visfatin are considered markers of visceral abdominal fat. Research design and methods: The mRNA content of omentin and visfatin was measured by qRT-PCR analysis of fat samples removed from humans undergoing cardiac or bariatric surgery. Results: Omentin mRNA in internal mammary fat was 3.5%, that in the upper thoracic subcutaneous fat was 4.7% while that in the other subcutaneous fat depots was less than 1% of omentin in epicardial fat. The distribution of visfatin mRNA did not vary between the five depots. Omentin mRNA was preferentially expressed in the nonfat cells of omental adipose tissue since the omentin mRNA content of isolated adipocytes was 9% of that in nonfat cells, and similar results were seen for visfatin. The amount of omentin mRNA in differentiated adipocytes was 0.3% and that of visfatin 4% of that in nonfat cells. The amount of omentin mRNA in preadipocytes was virtually undetectable while that of visfatin was 3% of that in freshly isolated nonfat cells from omental adipose tissue. Conclusion: Omentin mRNA is predominantly found in epicardial and omental human fat whereas visfatin mRNA is found to the same extent in epicardial, subcutaneous and omental fat.

The relationship between atherogenic index of plasma and epicardial adipose tissue in hemodialysis and peritoneal dialysis patients

“…32,33 In a recent study, the authors concluded that EAT acts as an extremely active organ that produces several bioactive adipokines, as well as proinflammatory and proatherogenic cytokines. [9][10][11][12][13] Levels of most of these proinflammatory cytokines were, in general, increased and these cytokines were found to be associated with atherosclerosis in ESRD patients. [34][35][36] In this study, we demonstrated that AIP and EAT measurements were increased in ESRD patients when compared with healthy subjects.…”

“…In a recent study, the authors demonstrated that EAT acts an extremely active organ that produces several bioactive adipokines, as well as proinflammatory and proatherogenic cytokines including tumor necrosis factor (TNF)-a, interleukin (IL)-6, resistin, visfatin, omentin, leptin, plasminogen activator inhibitor-1 (PAI-1) and angiotensinogen. [9][10][11][12][13] We recently showed that EAT is increased in HD and PD patients 14,15 and this active visceral fat tissue is closely related with malnutritioninflammation-atherosclerosis/calcification syndrome (MIAC) in this population. 16 Logarithmic ratio of triglycerides to HDL was defined as atherogenic index of plasma (AIP) and this index was found to be closely associated with atherosclerosis in general population.…”

Identification of cardiovascular genes in omentum from morbidly obese patients with type 2 diabetes

“…Other investigators have found no difference in gene expression between subcutaneous and visceral fat. 29,32 Theoretically, the direct link through the portal circulation of visceral adipose tissue to the liver 17 may lead to significant differences in metabolism of adipokines versus subcutaneous fat.…”

Thermogenic potential and physiological relevance of human epicardial adipose tissue

“…However, a direct microcirculatory interconnection between the two has not been established so far. 23,24 Nonetheless, owing to its unique anatomic juxtaposition, numerous plausible physiological roles have been offered to epicardial fat including, but not limited to, that (1) it serves as the anatomic site for the cardiac nervous system, 25 (2) it serves to cushion the coronary arteries against pulse wave torsion, 14 (3) it serves as a heating blanket to protect the myocardium during hypothermia, 26,27 (4) it is an immunological tissue that serves to protect the myocardium and coronaries against pathogens and inflammatory activators 28 and (5) it serves to maintain fatty acid homeostasis in the coronary microcirculation. 5 In a seminal study looking at the anatomy, histology and biochemical properties of epicardial fat across a spectrum of species, epicardial fat was reported to exhibit a higher capacity for breakdown, synthesis and release of fatty acids relative to other intra-abdominal fat depots in guinea pigs.…”