Cerebral blood vessel changes in old people.

We give an electron microscopic description of vascular convulates, which occur along with normal brain aging. They consist of up to 10 vessels which are surrounded by a common perivascular space. We can make clear that the convolutes consist exclusively of normal arterioles. Each single vessel shows endothelial cells without pores. The media is mostly composed of a single layer of smooth muscle cells which are surrounded by adventitial cells or their processes. The adventitial cells show a high amount of lipid inclusions. From microangiographic research it is obvious that the absolute increase in length of the vessels is the main factor in the genesis of vascular convolutes. According to experimental animal studies it seems likely that recurrent hypoxic conditions lead to a considerable increase in length in the cerebral arterioles in old people.