Plasma adrenomedullin levels in patients with polymyalgia rheumatica and giant cell arteritis

Objective. Plasma adrenomedullin (AM) levels are elevated in several inflammatory rheumatic diseases. The aims of the present study were: a) to assess whether plasma AM levels are abnormal in patients with polymyalgia rheumatica and giant cell arteritis (PMR and GCA) and b) to investigate if this parameter is related to clinical and biochemical indicators of disease activity in these patients. Materials and methods. AM plasma levels were analyzed in 17 patients with PMR and GCA and in 14 healthy subjects. Twelve patients (9 PMR and 3 GCA) were studied when they had active disease before any steroid therapy and the remaining 5 patients (2 PMR and 3 GCA) were in complete clinical remission and no longer receiving steroid treatment. AM was measured by a specific radioimmunoassay. Results. Plasma AM concentration was significantly higher in patients with active GCA compared to the control group (p < 0.05) and with patients with isolated PMR (p < 0.05). However, there were no significant differences between patients with active PMR and the control group. Within the PMR/-GCA group with active disease, AM plasma levels were positively correlated with ESR (r = 0.6, p = 0.02), and negatively with hematocrit (r = -0.57, p = 0.03) and hemoglobin (r = -0.55, p = 0.04). No correlations were found between AM and CRP. Conclusions. Plasma levels of AM are elevated in patients with active GCA and correlate with parameters that reflect the acute phase response. The differences in the secretion of AM between patients with PMR and GCA might reflect the severity of the vascular endothelial cell damage in these conditions. The role of AM in the pathogenesis of PMR and GCA needs to be assessed in a larger series of patients.