Objectives To investigate spontaneous adipocytokine secretion by subcutaneous abdominal adipose tissue (SAAT) explants obtained from patients with rheumatoid arthritis (RA).
Methods SAAT explants were obtained by 18 G needle biopsy form 18 RA patients (16F/2M, the mean age 58,5±3,6 years) dispersed and cultured in vitro (100mg tissue/ml). Select adipocytokines: leptin, adiponectin, IL-6, IL-8 and macrophage migration inhibiting factor (MIF) concentrations were measured in culturesupernatants using ELISA and in sera of patients. Body mass index (BMI), disease activity scores (DAS 28), x-ray Larsen scores, routine blood tests and other demographic and clinical information were obtained. The association of BMI with duration of the disease, DAS 28, CRP levels, ESR, x-ray scores and concentrations of adipocytokines was analysed using linear regression. The spontaneous adipocytokine secretion from SAAT was compared with serum levels of measured variables.
Results Disease activity of RA patients was high (DAS28 = 5,28±0,27SD, CRP levels 21.0±5,2 mg/l), mean disease duration 11,8±2,5 years, and patients BMI 26,98±1.28. Patients were treated with methotrexate (13) or leflunomide (1) or sulphasalazine (2) with low doses of prednisone (7). None had received biologics. The SAAT concentrations of IL-6 (1042±242 pg/100mg), IL-8 (3044±833 pg/100mg), MIF (2597±614 pg/100mg) were significantly higher (p<0,006) comparing to the serum levels of IL-6 (747±416 pg/ml), IL-8 (49,4±36,9 pg/ml), MIF (476±76 pg/ml). The SAAT leptin (1,828±0,29 ng/100mg) was significantly lower then the serum leptin levels (30,185±5,7 ng/ml, p<0.05). BMI values of patients correlated positively with the SAAT IL-8 concentrations (r=0,57 p<0.05) and with the serum leptin (r=0,58 p<0.05) level, and negatively with x-ray scores ((r= -0,62 p<0.05). We found positive correlation of serum CRP levels with SAAT IL-6 (r=0,66 p<0.05) but not with serum IL-6. X-ray scores correlated positively with the disease duration (r=0,77 p<0.05) and negatively with the SAAT IL-8 (r=-0.53 p<0.05).
Conclusions Our data suggest that subcutaneous abdominal adipose tissue may modulate the systemic inflammatory processes in RA releasing pro and anti-inflammatory mediators.
Further studies are needed to explore potential association between obesity, abdominal fat bioactivity and RA severity and progression
Disclosure of Interest None Declared