Extra-ocular muscle cells from patients with Graves' ophthalmopathy secrete α (CXCL10) and β (CCL2) chemokines under the influence of cytokines that are modulated by PPARγ

To our knowledge, no study has evaluated the involvement of T helper (Th)1- and Th2-chemokines in extra-ocular muscle (EOM) myopathy in "patients with thyroid-associated ophthalmopathy" (TAO-p). We tested the effects of interferon (IFN)γ and tumor necrosis factor (TNF)α stimulation, and of increasing concentrations of peroxisome proliferator-activated receptor (PPAR)γ agonists (pioglitazone or rosiglitazone; 0.1μM-20μM), on Th1-chemokine [C-X-C motif ligand (CXCL)10] and Th2-chemokine [C-C motif ligand (CCL)2] secretion in primary EOM cultures from TAO-p vs. control myoblasts. Moreover, we evaluated serum CXCL10 and CCL2 in active TAO-p with prevalent EOM involvement (EOM-p) vs. those with prevalent orbital fat expansion (OF-p). Serum CXCL10 was higher in OF-p and EOM-p vs. controls, while serum CCL2 was not significantly different in controls, or in OF-p and EOM-p. We showed the expression of PPARγ in EOM cells. In primary EOM cultures from TAO-p: a) CXCL10 was undetectable in the supernatant, IFNγ dose-dependently induced it, whereas TNFα did not; b) EOM produced basally low amounts of CCL2, TNFα dose-dependently induced it, whereas IFNγ did not; c) the combination of TNFα and IFNγ had a significant synergistic effect on CXCL10 and CCL2 secretion; and d) PPARγ agonists have an inhibitory role on the modulation of CXCL10, while they stimulate CCL2 secretion. EOM participates in the self-perpetuation of inflammation by releasing both Th1 (CXCL10) and Th2 (CCL2) chemokines under the influence of cytokines, in TAO. PPARγ agonist activation plays an inhibitory role on CXCL10, but stimulates the release of CCL2

Enalapril reduces proliferation and hyaluronic acid release in orbital fibroblasts

BACKGROUND: Orbital fibroblast proliferation and hyaluronic acid (HA) release are responsible for some of the clinical features of Graves' ophthalmopathy (GO). Thus, inhibition of these processes may be a possible therapeutic approach to this syndrome. Enalapril, a widely used antihypertensive drug, was found to have some inhibitory actions on fibroblast proliferation in cheloid scars in vivo, based on which we investigated its effects in primary cultures of orbital fibroblasts from GO patients and control subjects. METHODS: Primary cultures of GO and control fibroblasts were treated with enalapril or with a control compound (lisinopril). Cell proliferation assays, lactate dehydrogenase release assays (as a measure of cell necrosis), apoptosis assays, and measurement of HA in the cell media were performed. RESULTS: Enalapril significantly reduced cell proliferation in both GO and control fibroblasts. Because enalapril did not affect cell necrosis and apoptosis, we concluded that its effects on proliferation reflected an inhibition of cell growth and/or a delay in cell cycle. Enalapril significantly reduced HA concentrations in the media from both GO and control fibroblasts. CONCLUSIONS: Enalapril has antiproliferative and HA suppressing actions in both GO and control fibroblasts. Clinical studies are needed to investigate whether enalapril has any effects in vivo in patients with GO