Diabetes and brain ischemia.

Diabetes influences brain ischemia in a number of different ways. Diabetes causes and exacerbates macroangiopathies, increases the severity of ischemia, and increases stroke mortality. Unfortunately, few studies have examined in sufficient depth the influence of diabetes on the various vascular lesions that cause brain ischemia. These can be divided into: 1) cardiac-origin brain embolism; 2) atherosclerosis of the aorta and the large extracranial arteries--the internal carotid arteries (ICAs) and the vertebral arteries (VAs); 3) atherosclerosis of the large intracranial arteries--ICAs, anterior, middle, and posterior cerebral arteries, the VAs, and the basilar artery; 4) intracranial atheromatous branch disease of macroscopically visible branches of the intracranial arteries enumerated in 3; and 5) degenerative abnormalities such as lipohyalinosis and fibrinoid changes within penetrating artery branches visible only microscopically. The last three types of disorders all can cause deep subcortical brain infarcts, the predominant type of brain infarction found in Japan.