Scintigraphic Findings and Serum Matrix Metalloproteinase 3 and Vascular Endothelial Growth Factor Levels in Patients with Polymyalgia Rheumatica

Objective: Polymyalgia rheumatica (PMR) is an inflammatory rheumatic disease that affects elderly people and is associated with synovitis. Recently, matrix metalloproteinase 3 (MMP 3) and vascular endothelial growth factor (VEGF) were reported to be involved in the pathogenesis of PMR-related synovitis. New evidence regarding the pathogenesis of PMR has been found; however, the diagnosis and outcomes of PMR remain uncertain. A more valid and standardized set of diagnostic criteria for PMR that preferably include laboratory and radiological assessment is required to facilitate the diagnosis of PMR, which is at present primarily based on the clinical symptoms. Methods: We performed gallium-67 scintigraphy to determine the distribution of inflammation in 6 patients with PMR; we also measured the serum C-reactive protein (CRP), MMP 3, and VEGF levels before and after corticosteroid administration. Results: Symmetrical gallium uptake was observed in the shoulders of all PMR patients, the pelvic girdles of 3 patients, the knees of 5 patients, and the wrists of 4 patients. The serum CRP, MMP 3, and VEGF levels were significantly elevated in pretreated PMR patients. Daily administration of 20 mg corticosteroid promptly and significantly decreased the serum CRP and VEGF levels. Moreover, the serum CRP levels were significantly correlated with the serum VEGF levels. Serum MMP 3 levels were increased in three patients and were decreased in two patients by daily administration of 20 mg corticosteroid. Conclusions: Gallium-67 scintigraphy demonstrated the existence of peripheral articular synovitis as well as proximal articular synovitis, which are common symptoms of PMR, in the study patients. The elevated serum VEGF levels before treatment promptly decreased after corticosteroid administration, suggesting the significant association of VEGF with the pathogenesis of PMR.