QUERCETIN REDUCES PROLIFERATION AND HYALURONIC ACID RELEASE IN ORBITAL FIBROBLASTS: A POSSIBLE USE OF QUERCETIN IN GRAVES’ OPHTHALMOPATHY

Graves’ Ophthalmopathy (GO) is the complex of eye changes frequently observed in patients with Graves’ Disease (GD). In spite of the efforts made by investigators both in the basic and clinical fields, the knowledge of GO pathogenesis remains poor, because of which treatment is a difficult challenge, in that symptomatic rather than causal measures are employed. Inhibition of fibroblast (FB) proliferation and hyaluronic acid (HA) production may be a therapeutic approach to GO, especially in the early phases of GO, when most of the changes responsible for the onset of the disease occur in orbital FB. In the present study we evaluated the effects of quercetin on FB proliferation and GAG production. The flavonoid quercetin has a wide range of activities, including reduction of FB growth. We investigated the effects of quercetin in orbital FBs from GO patients and control subjects. Quercetin, but not its glycosides rutin and quercitrin, reduced cell proliferation, with no difference between GO and control FBs. A similar effect was obtained with other flavonoids (apigenin, luteolin, genistein) and with one of their glycosides genistin. The effects of quercetin on proliferation were due to necrosis and cell cycle blockade, whereas apoptosis was unaffected. Quercetin reduced HA in the cell media, with no difference between GO and control FBs. In conclusion, quercetin reduces cell proliferation and HA release in orbital FBs. Whether these initial findings have any potential for the use of quercetin in the clinical practice remains to be established.