The Synergistic Effect of Corticosteroids and Mycophenolic Acid on Chemokines in Orbital Cells From Patients With Graves’ Ophthalmopathy

Abstract

In recent studies, an improvement of the response rate to therapy has been reported with corticosteroids and mycophenolic acid in patients with Graves’ ophthalmopathy (GO). In GO, retro-orbital cells (fibroblasts, preadipocytes, and extraocular muscle cells) secrete Th1 and Th2 chemokines stimulated by cytokines. Until now, no studies are present in literature regarding the effect of corticosteroids and mycophenolic acid on the secretion of chemokines in GO orbital cells. For this reason, the effect of increasing concentrations of mycophenolic acid or corticosteroids on the secretion of either the Th1 (CXCL10) and Th2 (CCL2) chemokines was tested in primary cultures of myoblasts, preadipocytes and fibroblasts obtained from GO patients. CXCL10 was undetectable in the supernatants of the retro-orbital cells in primary cultures; its release was induced dose-dependently by IFNγ, while TNFα alone had no effect. On the contrary CCL2 release (that was produced in low amounts basally) was dose-dependently induced by TNFα, while IFNγ alone had no effect. In both cases the combination of TNFα and IFNγ had a significant synergistic effect on CXCL10 and CCL2 secretion. The release of these chemokines was dose-dependently inhibited by increasing concentrations of mycophenolic acid, or corticosteroids (in a pharmacological range), in presence of IFNγ and TNFα stimulation. Moreover, the association of corticosteroids and mycophenolic acid (in presence of IFNγ and TNFα) had a stronger inhibitory effect on the chemokines release. In conclusion, in GO orbital cells, mycophenolic acid and/or corticosteroids (in a pharmacological range) have an inhibitory role on the secretion of both Th1 (CXCL10) and Th2 (CCL2) chemokines. This suggests a possible therapeutic role of these drugs.