Background Proteolytic enzymes – Matrix Metalloproteinases (MMP), have a significant role in the process of bone and cartilage destruction in rheumatoid arthritis (RA).
Objectives Examination of the influence of the TNF-α gene polymorphism on the production of MMP-9 in the plasma (PL) and synovial fluid (SF) of patients suffering from RA.
Methods The examination included 72 patients with early RA and knee synovitis, receiving methotrexate therapy. RA diagnosis was established within 6 months from the onset of symptoms, based on the ACR/EULAR criteria from 2010. The control group comprised 25 examinees with knee osteoarthrosis (OA), who were comparable with the RA group according to their demographic characteristics (Table 1).
The -308 G/A gene polymorphism for TNF alpha was determined for all patients using the PCR-RFLP method. With regards to the presence of the A allele of the examined polymorphism, the patients were divided into two subgroups: subgroup A (G/A and A/A genotypes) and subgroup G (G/G genotype). The activity of MMP-9 was measured in PL and SF of all examinees using the sandwich enzyme-linked immunosorbent assay (ELISA) method, according to the instructions provided by the manufacturer (Amersham Biosciences, Little Chalfont, Great Britain). Statistical calculations were performed in the SPSS program, version 15.0
Results The activity of MMP-9 in PL and SF of the patients with RA is statistically significantly greater than the activity of this enzyme in PL and SF of the control group patients, with the statistically more significant difference (p<0.001) determined for the activity of MMP-9 in SF (15.07±13.24 to 0.65±0.41 ng/ml) in relation to the activity of this enzyme in PL (18.28±7.54 to 13.58±3.07 ng/ml), (p<0.01). Within the group of patients where the activity of MMP-9 in PL and SF was determined, 37 (51.39%) examinees belonged to Group A, while 35 (48.61%) belonged to Group G. A higher activity of MMP-9 both in PL and SF was registered in Group A than in Group G, with the statistical significance reached only for the activity of MMP-9 in SF (Table 2).
Conclusions The activity of MMP-9 in the plasma and synovial fluid of RA patients is greater than the activity of this enzyme in PL and SF of examinees with osteoarthrosis. The presence of the A allele of the TNF-α -308 G/A gene polymorphism is associated with the increased activity of MMP-9 enzyme in the synovial fluid of patients with early RA, and it can predict a faster radiological progression of the disease.
Disclosure of Interest None declared