TY - JOUR T1 - Knee and hip intra-articular adipose tissues (IAATs) compared with autologous subcutaneous adipose tissue: a specific phenotype for a central player in osteoarthritis JF - Annals of the Rheumatic Diseases JO - Ann Rheum Dis SP - 1142 LP - 1148 DO - 10.1136/annrheumdis-2016-210478 VL - 76 IS - 6 AU - Florent Eymard AU - Audrey Pigenet AU - Danièle Citadelle AU - Joan Tordjman AU - Louise Foucher AU - Cindy Rose AU - Charles-Henri Flouzat Lachaniette AU - Christine Rouault AU - Karine Clément AU - Francis Berenbaum AU - Xavier Chevalier AU - Xavier Houard Y1 - 2017/06/01 UR - http://ard.bmj.com/content/76/6/1142.abstract N2 - Objectives Compared with subcutaneous adipose tissue (SCAT), infrapatellar fat pad (IFP), the main knee intra-articular adipose tissue (IAAT), has an inflammatory phenotype in patients with osteoarthritis (OA). We phenotyped suprapatellar fat pad (SPFP) and hip acetabular fat pad (AFP), two other IAATs, to determinate the unique signature of IAATs compared with SCAT.Methods IFP, SPFP, AFP and autologous SCAT were obtained from patients with OA during total knee (n=38) or hip replacement (n=5). Fibrosis and adipocyte area were analysed by histology and vascularisation, leucocyte and mast cell infiltration were analysed by immunohistochemistry for von Willebrand factor, leucocytes and tryptase, respectively. Secretion of interleukin (IL)-6, IL-8 and prostaglandin E2 (PGE2) was assessed by ELISA. The mRNA expression of adipocyte-associated genes (ATGL, LPL, PPAR-γ, FABP4 and CD36) and developmental genes (SFRP2, HoxC9 and EN1) was determined. The inflammatory response of isolated fibroblast-like synoviocytes (FLS) to autologous IFP and SPFP conditioned media was examined.Results Fibrosis, vascularisation and leucocyte and mast cell infiltration were greater in IAATs than SCAT, and levels of IL-6, IL-8 and PGE2 were greater in all IAATs than SCAT. IFP and SPFP induced a similar inflammatory response to FLS. Adipocyte area was smaller in IAATs than SCAT. Adipocyte-associated and developmental genes showed a similar gene expression pattern in all IAATs, different from SCAT.Conclusions IFP but also SPFP and AFP (gathered under the term ‘IAAT’) may play a deleterious role in OA by affecting joint homeostasis because of their inflammatory phenotype and their close interaction with synovium in the same functional unit. ER -