ABSTRACT
Objective To determine the level of ieptin (LEP) and soluable leptin receptor (sLEP-R) in the peripheral blood of rheumatoid arthritis (RA). The change of LEP/sLEP-R in patients with RA and the relationship between LEP/sLEP-R with osteoporosis is also investigated. Methods Sixty-four patients with RA and 60 normal controls were involved. Levels of LEP and sLEP-R were measured by ELISA. Bone mineral density (BMD) of non-dominant forearm, lumbar vertebrae(L_(1～4)) and hip were measured by dual energy X-ray absorptiometry. Results ① Compared with normal controls, the level of LEP in RA increased significantly,but the level of sLEP-R in RA decreased significantly (P<0.01). ② BMD of all detected regions in RA were significantly reduced than those in the normal controls (P<0.01). There was a higher incidence of osteoporosis in patients with RA (35.9%) than in normal controls (15.0%)(P<0.01). ③ There was a positive lineary correlation between age and the level of LEP in the peripheral blood of RA (P<0.01). There was negative lineary correlations between BMD and level of LEP in the peripheral blood of RA (P<0.05). There was a negative lineary correlation between age and level of sLEP-R in the peripheral blood of RA (P<0.01). There was positive lineary correlation between BMD and level of sLEP-R in the peripheral blood of RA (P<0.05). There was no correlations between clinical or laboratory parameters and level of LEP/sLEP-R in the peripheral blood of RA. ④ Analysis of Logistic Regression showed that the level of sLEP-R in the peripheral blood of RA was an independent protective factor for the occurrence of osteoporosis in RA (OR=3.089, P=0.017, 95%CI: 0.017-7.108). Conclusion The level of LEP in RA increases significantly, while the level of sLEP-R decreases significantly. There is a closely correlation between bone metabolism status and the level of LEP or sLEP-R in RA. The level of sLEP-R in the peripheral blood of RA is an independent protective factor for the occurrence of osteoporosis in RA.