Gerodermia Osteodysplastica

Graves' orbitopathy (GO) is the most common extra-thyroidal manifestation of Graves' disease (GD), being observed in
25% of patients. Besides genetic and demographical variables, risk factors associated with the development of GO in GD patients are known to be inadequate control of hyperthyroidism, radioiodine treatment, and smoking. In a large retrospective study conducted in more than 8,000 individuals with GD it was observed that treatment with 3-hydroxy-3-methylglutaryl-coenzyme reductase inhibitors, better known as statins, is associated with a
40% reduced risk of developing GO in GD patients. The findings were interpreted as the consequence of the anti-inflammatory action of statins, being GO notoriously an autoimmune, inflammatory conditions.
Statins are widely used for the treatment of hypercholesterolemia, for which they are quite effective. The possibility that their "protective" effect in terms of GO development in GD patients, as observed by Stein et al., was simply due to their hypolipemic actions was not considered. To evaluate the possibility that the findings reflected lowering of cholesterol rather than a direct anti-inflammatory effect of statins a prospective, observational study to assess the association between GO and high cholesterol levels and/or the relationship between the degree and/or activity of GO and hypercholesterolemia is ongoing. Preliminary findings suggest that GO is more severe and active in patients with high cholesterol levels. On the basis of these observations, the present randomized clinical trial was designed to be performed in hypercholesterolemic patients with GD and moderate-to-severe and active GO, aimed at investigating if lowering of cholesterol levels with statins is associated with a better outcome of GO.

Graves orbitopathy (GO) is an inflammatory eye disease associated in 95% of patients with Graves' hyperthyroidism (GH), in
3-4% with hypothyroid autoimmune thyroiditis, and in
1-2% with thyroid autoimmunity in the absence of thyroid dysfunction, the former known as euthyroid GO. The pathogenesis of GO is autoimmune, with the TSH-receptor being considered the major autoantigen, thereby establishing a pathogenetic link between the thyroid and orbital tissue. Thus, TSH-receptor is expressed by orbital fibroblasts, where it forms a complex with the IGF-1 receptor. Unlike GH, which is notoriously caused by TSH-receptor stimulating autoantibodies, GO is believed to reflect cell-mediated autoimmunity, as suggested by studies showing a Th1-like pattern of cytokine release by primary cultures of orbital infiltrating lymphocytes from GO patients. On the other hand, a role of B lymphocytes has emerged in recent years based on the observation that the anti-CD20 monoclonal antibody rituximab has a beneficial effect on GO activity, as demonstrated by a recent randomized clinical trial in which rituximab was compared with intravenous glucocorticoids (GC), being the former the standard treatment of moderately-severe GO. The explanation for the findings was that B lymphocytes are involved in the pathogenesis of GO as antigen-presenting cells. However, in spite of the above mentioned promising observations, another randomized clinical trial in which rituximab was compared with placebo provided opposite results. Thus, rituximab had no effect at all on GO. Data from the two studies were confronted and major differences between the two cohorts emerged, especially concerning GO activity, leading to the conclusion that rituximab may be effective for active, but not for inactive GO. Rituximab has been employed also for autoimmune diseases other than GO, including type 1 diabetes. In the former, it was shown that the effectiveness of rituximab paralleled the presence of CD20-positive infiltrating lymphocytes in pancreas islets. We therefore postulated that something similar may occur in GO, because of which we planned the present, perspective, observational study, aimed at determining the presence and immunohistochemical features of lymphocytes infiltrating orbital tissues in patients with GO and to relate them with the clinical features of GO.