Relation between serum uric acid and carotid intima-media thickness in healthy postmenopausal women

OBJECTIVE: Serum uric acid (SUA) is associated with cardiovascular disease (CVD). However it is still disputed whether the relationship is mediated by other risk factors such as obesity, dyslipidaemia, hypertension and insulin resistance. We explored the association of the uric acid level with carotid intima-media thickness (IMT), a well known marker of CVD, in postmenopausal healthy women. METHODS: We consecutively enrolled postmenopausal women undergoing a screening for health evaluation. After an accurate clinical examination, and a biochemical evaluation, the enrolled subjects underwent B mode ultrasonography to assess common carotid intima media thickness. RESULTS: Among 234 women aged 45-70 years, the uric acid level is associated with carotid IMT independently of other prognostic factors (p=0.03). In particular, women in the highest tertiles of uric acid level have a greater IMT than women in the lowest tertile (p=0.007). CONCLUSIONS: Independently of other cardiovascular risk factors, SUA levels are associated with carotid IMT even in subjects without the metabolic syndrome. This confirms and expands the role of uric acid in the determinism of CVD. Prospective trials would be useful to evaluate interventions aimed at lowering the uric acid level

Xanthine oxidase and uric acid in cardiovascular disease: clinical impact and therapeutic options

The association between increased uric acid (UA) levels and cardiovascular disease (CVD) has been observed and studied for many decades. The value of UA as an independent factor within the metabolic risk profile for prediction of CVD in the normal population remains an issue of ongoing discussion. In turn, increasing evidence suggests that among patients with established CVD such as heart failure UA is an independent marker of disease state and prognosis. Increased UA levels may be an indicator of up-regulated activity of xanthine oxidase, a powerful oxygen radical-generating system in human physiology. Increased reactive oxygen species (ROS) accumulation contributes to endothelial dysfunction, metabolic and functional impairment, inflammatory activation, and other features of cardiovascular pathophysiology. Accordingly, inhibition of xanthine oxidase activity has been shown to improve a range of surrogate markers in patients with CVD, but this effect seems to be confined to hyperuricemic patients because disappointing results were reported in studies with normouricemic patients. In this review we summarize current evidence on hyperuricemia in CVD. The value of UA as a biomarker and as a potential therapeutic target for tailored metabolic treatment in CVD is discussed

A Unique Case of Thrombosed Giant Popliteal Aneurysm

We report a unique case of a giant, thrombosed, and ruptured popliteal aneurysm measuring 13.8 cm x 14.0 cm x 14.0 cm in a 93-year-old man. The patient is a hypertensive smoker with asymptomatic swelling behind the knee for several years who developed pain in the swelling with ecchymosis for 2 weeks before presentation. Despite rupture of the aneurysm, this patient exhibited no ischemic symptoms. The patient underwent emergency surgery in which most of the aneurysmal sac was excised and because of satisfactory collateral circulation, the proximal and distal popliteal artery was suture-ligated. Remarkably, the patient did not require a bypass graft and at follow up is pain-free and ambulating with no clinical signs or symptoms of ischemia. This case is unique in several ways: 1) to our knowledge, this is the largest popliteal aneurysm compared with any case that has been documented in the literature, 2) this is also the oldest reported age ever associated with a popliteal aneurysm, and 3) exclusion suture ligation proximally and distally has resulted in an exceptional outcome. </jats:p

Detection of xanthine oxidase in human atherosclerotic specimens and arterialized vein grafts

Xanthine oxidase is an essential enzyme in the formation of uric acid and has been previously identified by immunohistochemistry in liver, intestine and capillary endothelial cells. The purpose of this study was to investigate the presence of xanthine oxidase in human atherosclerotic plaques. Atherosclerotic plaques from carotid endarterectomy pathology specimens were snap frozen in liquid nitrogen, placed in an OCT block, and cut to a thickness of 6 microns with a cryotome. Slides were stored at -120° C until ready for staining Immunohistochemical staining, using a polyclonal rabbit anti-xanthine oxidase antibody (Fitzgerald, Concord MA), was performed on 17 specimens which included 14 carotid endarterectomy plaques, 2 transplant donors and 1 arterialized saphenous vein graft. The staining for xanthine oxidase was found to be positive in carotid artery from transplant donors, carotid artery plaques and the arterialized vein graft. The carotid artery of donors was found to have positive staining in the intima that was less than the staining of smooth muscle cells in the media. Occasional cells the adventitia also stained positive. The carotid plaques were found to be irregularly stained, with endothelial cells and smooth muscle cells staining positive in the intima. The thickened intimal and medial areas of the plaques had cholesterol clefts whose periphery stained more intensively than the rest of the plaque. Additional staining using an antibody against uric acid crystals was, likewise, positive in these areas. In the arterialized vein graft, endothelial cells and smooth muscle cells, likewise, stained positive for xanthine oxidase in the thickened intima. The layers beyond the elastic lamina were negative. These results suggest that xanthine oxidase is expressed in smooth muscle cells and endothelial cells. The identification of xanthine oxidase in the plaque of disease arteries and arterialized vein graft suggest a possible relationship between the presence of xanthine oxidase and the development of atherosclerosis and/or intimai hyperplasia