Raised levels of F-2-isoprostanes and prostaglandin F-2 alpha in differentrheumatic diseases

Objective-To evaluate oxidative injury and inflammatory status in various r heumatic diseases by measuring the levels of isoprostanes and prostaglandin s in serum and synovial fluid. Methods-The concentrations of 8-iso-PGF(2 alpha) (F-2-isoprostane indicatin g oxidative injury) and 15-keto-dihydro-PGF(2 alpha) (a major metabolite of prostaglandin F-2 alpha) were measured in both serum and synovial fluid as pirated from 26 patients with various arthritic diseases, including rheumat oid arthritis (RA), reactive arthritis (ReA),psoriatic arthritis (PsA),and osteoarthritis (OA). These prostaglandin derivatives were also measured in serum samples collected from 42 healthy control subjects. Results-Overall, serum levels; of 8-iso-PGF(2 alpha) and 15-keto-dihydro-PG F(2 alpha) were much higher in patients with arthritic diseases than in the healthy control subjects. The levels of 8-iso-PGF(2 alpha) and 15-ketodihy dro-PGF(2 alpha) in synovial fluid aspirated from knee joints were also hig h and varied among various types of arthritic patients. Although the synovi al fluid level of these prostaglandin derivatives was sometimes higher than in the corresponding serum sample, this was not a consistent finding. Over all, there was no correlation between serum and synovial fluid levels of 8- iso-PGF(2 alpha), or between serum and synovial fluid levels of 15-keto-dih ydro-PGF(2 alpha). However, a strong relation was found between the levels of 8-iso-PGF(2 alpha) and 15-keto-dihydro-PGF(2 alpha), in both serum (r(s) =0.53, p<0.001) and synovial fluid (r(s)=0.62, p<0.001). Conclusions-These data suggest that both free radical mediated oxidative in jury and cyclo-oxygenase dependent inflammatory responses are closely corre lated in various types of arthritis.