Hyperuricaemia Does Not Interfere With Aortopathy in a Murine Model of Marfan Syndrome

Abstract

Redox stress is involved in the aortic aneurysm pathogenesis in Marfan syndrome (MFS). We recently reported that allopurinol, a recognised inhibitor of XOR, inhibited aortopathy in a mouse model of MFS acting as an antioxidant. Hyperuricaemia is ambiguously associated with cardiovascular injuries as uric acid (UA), having antioxidant or pro-oxidant properties depending on the concentration and accumulation site. We aimed to evaluate whether hyperuricaemia causes harm or relief in MFS aortopathy and cardiopathy pathogenesis. Two-month-old male wild-type (WT) and MFS mice (Fbn1C1041G/+) were injected intraperitoneally for several weeks with potassium oxonate (PO), an inhibitor of uricase, an enzyme that catabolises UA to allantoin. Plasma UA and allantoin levels were measured via several techniques, aortic root diameter and cardiac parameters by ultrasound imaging, aortic wall structure by histopathology, and pNRF2 levels by immunofluorescence. PO induced a significant increase in UA in blood plasma both in WT and MFS mice, reaching a peak at three and four months of age but decaying at six months. Hyperuricaemic MFS mice showed no change in the characteristic aortic aneurysm progression or aortic wall disarray evidenced by large elastic laminae ruptures. There were no changes in cardiac parameters or the redox stress-induced nuclear translocation of pNRF2 in the aortic tunica media. Altogether, the results suggest that hyperuricaemia interferes neither with aortopathy nor cardiopathy in MFS mice.