Bone marrow blood vessels of long bones in rats progressively ossify as a function of advancing age.

The pathology appears to be a cellular-based transformation of vascular cells into bone.

Such pathology has been confirmed to exist in human subjects.

Ossification presumably results in “microvascular dead space,” i.e., loss of vessel patency and function as opposed to vascular necrosis.

This pathology may provide the common link associated with age-related changes in bone and bone marrow.