Vascular disease is the leading cause of death and disability in the Western world. In most cases, tissue ischemia results from the accretion of atherosclerotic plaque. Eventually, blood flow is compromised, and ischemia of dependent organs follows. Arterial wall inflammation is not a primary pathogenetic factor, but it may contribute to the progressive occlusion of the arterial lumen (1). In vasculitis, the blood vessel wall is the primary site of inflammation. However, the mechanisms leading to clinical manifestations are less well understood. In contrast to atherosclerotic vascular disease, which is slowly progressive, vascular complications of inflammatory vasculopathies are frequently of sudden onset. Often, they are combined with and sometimes preceded by systemic manifestations. Vasculitides can produce life-threatening complications and have a unique position among the rheumatic diseases.
Vasculitides are a heterogeneous group of syndromes, but classifications based on the size of the affected blood vessel have shown to be useful for clinical and pathologic studies (2). Large arteries, such as the aorta and its major branches, are the preferred target for 2 vasculitic entities, giant cell arteritis (GCA) and Takayasu arteritis (3). In the present article, we review the pathogenesis of GCA with particular emphasis on the molecular mechanisms involved in arterial wall injury.
An emerging theme in exploring the pathways of disease in GCA has been that the arterial wall is not simply an innocent battleground of an ongoing immune response. Rather, the arterial wall responds to the injury with a series of specific reactions, some of which hold the key to understanding why patients with inflammation in the arterial wall develop symptoms. This hypothesis also