title: Serum levels of interleukin-17 and adiponectin are associated with infrapatellar fat pad volume and signal intensity alteration in patients with knee osteoarthritis.
abstract: In the present study, we sought to generate hypotheses regarding the associations of serum levels of interleukin (IL)-17, adiponectin, and resistin with magnetic resonance imaging-measured infrapatellar fat pad (IPFP) size and signal intensity alterations in patients with knee osteoarthritis (OA).
  
  
  
  A total of 170 subjects with symptomatic knee OA (mean age 55.4 years, range 34-74, 88.2 % females) were included. IPFP volume was measured on T1-weighted spoiled gradient-recalled acquisition in the steady state images and was computed by using a software program. IPFP high signal intensity (grades 0-3) was assessed on T2-weighted fast spin echo images. Serum IL-17, adiponectin, and resistin levels were measured using an enzyme-linked immunosorbent assay.
  
  
  
  In multivariable analyses, serum IL-17 was negatively associated with IPFP volume (β = -0.185, 95 % CI -0.337 to -0.034) but positively associated with the severity of IPFP signal intensity alteration (OR 1.23, 95 % CI 1.06-1.42) after adjustment for age, sex, weight, and height. Serum adiponectin was positively associated with IPFP volume (β = 0.016, 95 % CI 0.001-0.032) but negatively associated with IPFP signal intensity alteration (OR 0.99, 95 % CI 0.98-1.00) after adjustment for covariates. Resistin was positively associated with IPFP signal intensity alteration (OR 1.13, 95 % CI 1.04-1.23) but not with IPFP volume. The significant associations of adiponectin or resistin disappeared after further adjustment for IL-17; in contrast, the significant associations of IL-17 remained after further adjustment for adiponectin.
  
  
  
  While serum IL-17 and resistin were associated with reduced IPFP volume and/or increased abnormal signal intensity alteration, serum adiponectin had opposite associations that were largely through IL-17. These findings suggest that serum adipocytokines may have a role to play in IPFP changes of knee OA.
authors: Department of Rheumatology and Immunology, Arthritis Research Institute, the First Affiliated Hospital of Anhui Medical University, 218 Jixi Street, Hefei, China.|Menzies Institute for Medical Research, University of Tasmania, Private Bag 23, Hobart, Tasmania, 7000, Australia.
authors: Kang
authors: K
authors: Wang
authors: Department of Rheumatology and Immunology, Arthritis Research Institute, the First Affiliated Hospital of Anhui Medical University, 218 Jixi Street, Hefei, China.
authors: Jianhua
authors: J
authors: Xu
authors: Department of Rheumatology and Immunology, Arthritis Research Institute, the First Affiliated Hospital of Anhui Medical University, 218 Jixi Street, Hefei, China.
authors: Jingyu
authors: J
authors: Cai
authors: Department of Rheumatology and Immunology, Arthritis Research Institute, the First Affiliated Hospital of Anhui Medical University, 218 Jixi Street, Hefei, China.
authors: Shuang
authors: S
authors: Zheng
authors: Menzies Institute for Medical Research, University of Tasmania, Private Bag 23, Hobart, Tasmania, 7000, Australia.
authors: Weiyu
authors: W
authors: Han
authors: Menzies Institute for Medical Research, University of Tasmania, Private Bag 23, Hobart, Tasmania, 7000, Australia.
authors: Benny
authors: B
authors: Antony
authors: Department of Rheumatology and Immunology, Arthritis Research Institute, the First Affiliated Hospital of Anhui Medical University, 218 Jixi Street, Hefei, China. changhai.ding@utas.edu.au.|Menzies Institute for Medical Research, University of Tasmania, Private Bag 23, Hobart, Tasmania, 7000, Australia. changhai.ding@utas.edu.au.
authors: Changhai
authors: C
authors: Ding
mesh_terms: D052242:Adiponectin / Q000097:blood*; D000273:Adipose Tissue / Q000000981:diagnostic imaging / Q000473:pathology*; D000328:Adult; D000368:Aged; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D020381:Interleukin-17 / Q000097:blood*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000097:blood / Q000000981:diagnostic imaging / Q000473:pathology*; D052243:Resistin / Q000097:blood
chemical_list: C499918:ADIPOQ protein, human; D052242:Adiponectin; C508717:IL17A protein, human; D020381:Interleukin-17; C499624:RETN protein, human; D052243:Resistin
keywords: Adipokines; Cartilage; Cytokines; Epidemiology; Infrapatellar fat pad; Osteoarthritis