Adenosine Receptors Profile in Fibromuscular Dysplasia

Fibromuscular dysplasia (FMD) is a non-inflammatory vascular disease that is characterized by unexplained systemic hypertension occurring in young people, associated with arterial stenosis, aneurysm rupture, intracranial/renal infarction, and stroke. Although the gold standard for the diagnosis remains catheter-angiography, biological markers would be helpful due to the delay from first symptom to diagnosis. Adenosine is an ATP derivative, that may be implicated in FMD pathophysiology. We hypothesized that changes in adenosine blood level (ABL) and production of adenosine receptors may be associated with FMD. Using peripheral blood mononuclear cells, we evaluated A(1), A(2A), and A(2B) receptor production by Western blot, in 67 patients (17 men and 50 women, mean (range) age 55 (29–77) years and 40 controls, 10 men and 30 women, mean (range) age 56 (37–70)). ABL was evaluated by liquid chromatography, mass spectrometry. ABL was significantly higher in patients vs. controls, mean (range): 1.7 (0.7–3) µmol/L vs. controls 0.6 (0.4–0.8) µmol/L (+180%) p < 0.001. While A(1)R and A(2A)R production did not differ in patients and controls, we found an over-production of A(2B)R in patients: 1.70 (0.90–2.40; arbitrary units) vs. controls = 1.03 (0.70–1.40), mean + 65% (p < 0.001). A(2B)R production with a cut off of 1.3 arbitrary units, gives a good sensitivity and specificity for the diagnosis. Production measurement of A(2B)R on monocytes and ABL could help in the diagnosis, especially in atypical or with poor symptoms.