Faculty Bibliography

PURPOSE OF REVIEW: The introduction of tumor necrosis factor-alpha antagonists in 1998 has had a significant impact on the treatment of rheumatoid arthritis. However, as use of these agents has increased worldwide, infrequent adverse events that were not apparent in pivotal controlled clinical trials required for registration have emerged. RECENT FINDINGS: These adverse events include serious infections, particularly tuberculosis, which may be atypical in presentation. Concern regarding increased risk of lymphoma has also emerged, although it remains unclear whether the risk exceeds that observed in other rheumatoid arthritis patients with comparable disease activity. Development of a systemic lupus erythematosus-like syndrome, which typically abates after discontinuation of the drug, is another rare complication that was further reported during the past year. Finally, additional cases of congestive heart failure and demyelinating syndromes (including cases resembling progressive multifocal leukoencephalopathy) have been reported that appear to be related to the tumor necrosis factor-alpha antagonists. SUMMARY: Additional postmarketing surveillance of these and other serious adverse events is necessary to determine the true risk of their occurrence, and whether a reassessment of the overall risk-benefit of tumor necrosis factor-alpha antagonists will be required

We examined the regulation of matrix metalloproteinase (MMP) production by mitogen-activated protein kinases and cyclooxygenases (COXs) in fibroblast-like synoviocytes (FLSCs). IL-1beta and TNF-alpha stimulated FLSC extracellular signal-regulated kinase (ERK) activation as well as MMP-1 and -13 release. Pharmacologic inhibitors of ERK inhibited MMP-1, but not MMP-13 expression. Whereas millimolar salicylates inhibited both ERK and MMP-1, nonsalicylate COX and selective COX-2 inhibitors enhanced stimulated MMP-1 release. Addition of exogenous PGE(1) or PGE(2) inhibited MMP-1, reversed the effects of COX inhibitors, and inhibited ERK activation, suggesting that COX-2 activity tonically inhibits MMP-1 production via ERK inhibition by E PGs. Exposure of FLSCs to nonselective COX and selective COX-2 inhibitors in the absence of stimulation resulted in up-regulation of MMP-1 expression in an ERK-dependent manner. Moreover, COX inhibition sufficient to reduce PGE levels increased ERK activity. Our data indicate that: 1) ERK activation mediates MMP-1 but not MMP-13 release from FLSCs, 2) COX-2-derived E PGs inhibit MMP-1 release from FLSCs via inhibition of ERK, and 3) COX inhibitors, by attenuating PGE inhibition of ERK, enhance the release of MMP-1 by FLSC