[Association of single nucleotide polymorphisms (SNPs) in leptin receptor gene with knee osteoarthritis in the Ningxia Hui population].

To investigate the association between primary knee osteoarthritis (OA) and single nucleotide polymorphism (SNP) (A668G) of leptin receptor gene (LEPR) in the Ningxia Hui population. A case-control association study has been adopted in this thesis. The polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP) analysis were performed to investigate the SNP of A668G site within LEPR from 148 patients with knee OA and 155 controls (asymptomatic and radiographically negative) with matched age and gender among Ningxia Hui population. In addition, genotypes of LEPR were verified by direct sequence analysis on PCR products. The result indicates that allele and genotype frequencies (P=0.024 and 0.008, respectively) in LEPR SNP A668G were significantly different in the knee OA patients group and control group, and in the knee OA patients group, the serum levels of leptin decreased significantly (P<0.001) and the serum levels of soluble leptin receptor increased significantly (P<0.001) compared with control group. Therefore, LEPR SNP A668G is associated with susceptibility to knee OA, which would be used as the genetic marker in predicting the risk of knee OA and would be one of the candidate genes in early prevention and control.

Detection of anti-cyclic citrullinated peptide antibodies in rheumatoid arthritis patients undergoing total knee arthroplasty.

Rheumatoid arthritis (RA) is the most common chronic inflammatory joint disorder and anti-cyclic citrullinated peptide antibody (anti-CCP Ab) is regarded as a serological marker for diagnosing early and late RA. In the present study, we aimed to determine the levels of anti-CCP Ab in serum, synovial tissue (ST) and synovial fluid (SF) in RA patients undergoing total knee arthroplasty (TKA). 23 patients were included. Rheumatoid factor (RF) and anti-CCP Ab in serum were detected prior to surgery and then at 1, 3, 6 and 12 months after TKA. Synovial samples were obtained by knee arthroscopy and used for anti-CCP detection. One month after TKA, anti-CCP levels were significantly reduced (P < 0.01) in RA patients. However, their levels were not significantly different between pre-surgery and 1 year post-surgery (P > 0.05). Furthermore, anti-CCP levels in ST were much higher than in serum. These findings suggest that RA patients should continue antirheumatic therapy after TKA. ST is the preferred place for the synthesis of anti-CCP Ab.