Whole orbital tissue culture identifies imatinib mesylate and adalimumab as potential therapeutics for Graves' ophthalmopathy

Abstract

Background and Aims

Orbit-Infiltrating Mast Cells, Monocytes, and Macrophages Produce PDGF Isoforms that Orchestrate Orbital Fibroblast Activation in Graves' Ophthalmopathy

“…Previously imatinib mesylate was found to block PDGF-BB-induced cytokine production, hyaluronan production, and proliferation by orbital fibroblast (14,15). Moreover, imatinib mesylate reduced IL-6 and hyaluronan production in cultures of whole orbital tissue from GO patients (16). However, imatinib mesylate not only targets PDGF receptor tyrosine kinase activity (40) and may therefore interfere with other biological processes as well.…”

“…To test this, we used our recently published whole orbital tissue culture approach (16) and tested the effect PDGF-AA-and PDGF-BB-neutralizing antibodies and imatinib mesylate herein. PDGF-BB-neutralizing antibody inhibited IL-6 and hyaluronan production by orbital tissues, whereas the effect of the PDGF-AA-neutralizing antibody was variable (Fig.…”

“…Culture supernatants were subjected to IL-6 and hyaluronan ELISA. Detected values were corrected for the orbital tissue weight and expressed as inhibition index (calculated as 1 Ϫ the production levels achieved with medication/production levels without medication) (16).…”

“…Orbital tissue cultures were essentially performed as described previously (16). Briefly, orbital tissues from three GO patients were each cut into seven pieces and incubated in DMEM 1% FCS with or without PDGF-AA-neutralizing antibodies (40 and 20 g/ml; R&D Systems), PDGF-BB-neutralizing antibodies (4 and 2 g/ml; R&D Systems) or imatinib mesylate (2.5 g/ml) for 48 h. As the neutralizing capacity of the PDGF-BB-neutralizing antibody [50% neutralization dose (ND 50 ) ϭ 1 g/ml] was 10-fold higher than the neutralizing capacity of the PDGF-AA neutralizing antibody (ND 50 ϭ 10 g/ml), 10-fold lower concentrations of the PDGF-BB-neutralizing antibody were used.…”

THERAPY OF ENDOCRINE DISEASE: Endocrine dilemma: management of Graves’ orbitopathy

“…Although trials with first-generation inhibitors, such as wortmannin, LY294002, or rapamycin and its derivatives, have been stopped because of significant untoward effects, second-generation inhibitors are currently being used in clinical trials on patients with refractory cancers (93), but to date, no trials have been planned in autoimmune thyroid disease. A PDGF-BB isoform of the PDGF receptor has recently been found expressed and increased in the orbital tissue of GO patients (94,95,96,97). Its signaling on orbital fibroblast can be blocked by tyrosine kinase inhibitors, such as imatinib mesylate, nilotinib ,and dasatinib, which has been shown to decrease in vitro the mRNA expression of hyaluronic synthetase 2 and IL-6 and IL-8 cytokines in orbital tissue from active GO (96) (Fig.…”