Extracranial Internal Carotid Artery Aneurysm in a Patient with Marfan Syndrome.

Extracranial internal carotid artery (ICA) aneurysms are rare and most of them are considered of atherosclerotic etiology. Marfan syndrome (MS) is a systemic connective tissue disorder caused by mutation in the extracellular matrix protein fibrillin 1. Clinical manifestations of the MS include aortic aneurysms, dislocation of the ocular lens, and long bone overgrowth. The presence of extracranial ICA aneurysm in patients with MS is very rare. We report a 62-year-old female patient with MS presented with an extracranial ICA aneurysm. She was treated with aneurysmectomy and end-to-end anastomosis, with good outcomes. Only 10 cases of patients with MS and extracranial ICA aneurysm have been described in the literature. Clinical presentation, treatment, and outcome of these patients are reviewed and discussed.

Hypoxia inducible factor as a therapeutic target for atherosclerosis.

Atherosclerosis is a highly prevalent disease that can significantly increase the risk of major vascular events, such as myocardial or cerebral infarctions. The anoxemia theory states that a disparity between oxygen supply and demand contributes to atherosclerosis. Hypoxia inducible factor-1 (HIF-1) is a heterodimeric protein, part of the basic helix-loop-helix family and one of the main regulators of cellular responses in a low­oxygen environment. It plays a key role in the development of atherosclerosis through cell-specific responses, acting on endothelial cells, vascular smooth muscle cells (SMCs) and macrophages. Through the upregulation of VEGF, NO, ROS and PDGF, HIF-1 is able to cause endothelial cell dysfunction, proliferation, angiogenesis and inflammation. Activation of the NF-kB pathway in endothelial cells is an important contributor to inflammation and positively feedbacks to HIF-1. HIF-1 also plays a significant role in both the proliferation and migration of smooth muscle cells - two important features of atherosclerosis, while the formation of foam cells (lipid-laden macrophages) is also a critical step in atherosclerosis and mediated by HIF-1 through various mechanisms such as dysfunctional efflux pathways in macrophages. Overall, HIF-1 exerts its effect on the pathogenesis of atherosclerosis via a variety of molecular and cellular events in the process. In this review article, we examine the effects HIF-1 on vascular cells and macrophages in the development of atherosclerosis, highlighting the environmental cues and signalling pathways that control HIF-1 expression/activation within the vasculature. We will highlight the potential of HIF-1 as a therapeutic target on the disease development.