Pioglitazone reduces inflammatory responses of human adipocytes to factors secreted by monocytes/macrophages.
Infiltration of monocyte-derived macrophages into adipose tissue may contribute to tissue and systemic inflammation and insulin resistance. We hypothesized that pioglitazone (Pio) could specifically reduce the inflammatory response of adipocytes to factors released by monocytes/macrophages. We show that macrophage factors (Mphi-factors) greatly increase expression levels of proinflammatory adipokines, chemokines, and adhesion molecules in human subcutaneous and visceral adipose tissue (SAT and VAT) as well as in adipocytes (up to several hundredfold of control). Compared with SAT, VAT showed enhanced basal and Mphi-factor-induced inflammatory responses. Mphi-factors also induced greater lipolysis in adipocytes, as assessed by concentrations of glycerol released from the cells (196 +/- 13 vs. 56 +/- 7 microM in control, P < 0.05). Pretreatment of adipose tissue or adipocytes with Pio reduced these responses to Mphi-factors (by 13-86%, P < 0.05) and prevented Mphi-factor suppression of adiponectin expression. Furthermore, Pio pretreatment of adipocytes and macrophages tended to further reduce inflammatory responses of adipocytes to Mphi-factors and monocyte adhesion to Mphi-factor-activated adipocytes. In support of these in vitro data, media conditioned by monocytes isolated from impaired glucose-tolerant subjects treated with Pio (compared with placebo) induced release of lower concentrations of proinflammatory adipokines and glycerol (100 +/- 7 vs. 150 +/- 15 microM, P < 0.05) from adipocytes. In summary, Pio decreases inflammatory responses in adipose tissue/cells induced by monocytes/macrophages by acting on either or both cell types. These beneficial effects of Pio may attenuate proinflammatory responses resulting from monocyte/macrophage infiltration into adipose tissue and suppress tissue inflammation resulting from the interaction between both cell types.
Permana
Paska A
PA
Phoenix Veterans Affairs Health Care System, Phoenix, AZ 85012-1892, USA. Paska.Permana@va.gov
Zhang
Weiyang
W
Wabitsch
Martin
M
Fischer-Posovszky
Pamela
P
Duckworth
William C
WC
Reaven
Peter D
PD
D017667:Adipocytes / Q000187:drug effects / Q000276:immunology; D054392:Adipokines / Q000096:biosynthesis / Q000235:genetics; D018932:Chemokine CCL2 / Q000096:biosynthesis / Q000235:genetics; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D007004:Hypoglycemic Agents / Q000494:pharmacology*; D018836:Inflammation Mediators / Q000276:immunology* / Q000378:metabolism; D015850:Interleukin-6 / Q000096:biosynthesis / Q000235:genetics; D050152:Intra-Abdominal Fat / Q000187:drug effects* / Q000276:immunology / Q000473:pathology; D008264:Macrophages / Q000187:drug effects / Q000276:immunology / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D000077205:Pioglitazone; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D050151:Subcutaneous Fat / Q000187:drug effects* / Q000276:immunology / Q000473:pathology; D045162:Thiazolidinediones / Q000494:pharmacology*; D020298:U937 Cells; D019010:Vascular Cell Adhesion Molecule-1 / Q000096:biosynthesis / Q000235:genetics
D054392:Adipokines; C111835:CCL2 protein, human; D018932:Chemokine CCL2; D007004:Hypoglycemic Agents; D018836:Inflammation Mediators; D015850:Interleukin-6; D012333:RNA, Messenger; D045162:Thiazolidinediones; D019010:Vascular Cell Adhesion Molecule-1; D000077205:Pioglitazone