title: Adipose tissue IL-6 content correlates with resistance to insulin activation of glucose uptake both in vivo and in vitro.
abstract: Obesity and type 2 diabetes are associated with insulin resistance, the mechanisms of which remain poorly understood. A significant correlation between circulating IL-6 level and insulin sensitivity has recently been found in humans. Because adipose tissue could be a significant source of IL-6, we analyzed the relationship between the levels of adipose tissue IL-6 and insulin action in vivo, during a hyperinsulinemic normoglycemic clamp, and in vitro by measuring glucose transport in adipocytes from 12 obese subjects with (n = 7) or without (n = 5) diabetes. We observed an inverse correlation between adipose tissue IL-6 content and maximal insulin-responsiveness measured in vivo (P < 0.02) and in vitro (P < 0.02). Conversely, there was no significant correlation between these two later parameters and adipose tissue leptin or tumor necrosis factor-alpha protein contents. Furthermore, we showed, for the first time, the presence of immunoreactive IL-6 receptors in the plasma membrane of human abdominal sc adipocytes. This suggests that locally secreted IL-6 could act on adipocytes by an autocrine/paracrine mechanism. In conclusion, increased IL-6 production by sc adipose cells might participate to the insulin-resistant state observed in human obesity.
authors: Service de Biochimie et Hormonologie, Hôpital Tenon-Rothschild, Assistance Publique-Hôpitaux de Paris (AP-HP), 75020 Paris, France. jean-philippe.bastard@tnn.ap-hop-paris.fr
authors: Jean-Philippe
authors: JP
authors: Bastard
authors: Mustapha
authors: M
authors: Maachi
authors: Jeanne Tran
authors: JT
authors: Van Nhieu
authors: Claude
authors: C
authors: Jardel
authors: Eric
authors: E
authors: Bruckert
authors: André
authors: A
authors: Grimaldi
authors: Jean-Jacques
authors: JJ
authors: Robert
authors: Jacqueline
authors: J
authors: Capeau
authors: Bernard
authors: B
authors: Hainque
mesh_terms: D000273:Adipose Tissue / Q000378:metabolism*; D000328:Adult; D016207:Cytokines / Q000097:blood / Q000378:metabolism; D003924:Diabetes Mellitus, Type 2 / Q000150:complications* / Q000503:physiopathology; D005260:Female; D005947:Glucose / Q000378:metabolism*; D006801:Humans; D007150:Immunohistochemistry; D066298:In Vitro Techniques; D007328:Insulin / Q000502:physiology; D007333:Insulin Resistance / Q000502:physiology*; D015850:Interleukin-6 / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000150:complications* / Q000378:metabolism*; D012016:Reference Values
chemical_list: D016207:Cytokines; D007328:Insulin; D015850:Interleukin-6; D005947:Glucose