Research Description:

Endothelial cells normally line the blood vessels of the body and may be derived from any part of the vascular tree. There are small numbers of endothelial cells that circulate in the bloodstream and are called circulating endothelial cells (CEC). CECs were first detected in the 1970s although convenient techniques to isolate them have only recently become available. These cells may come from large or small veins, arteries, or from capillaries. These cells may also be derived from progenitor cells from the bone marrow. Although these circulating endothelial cells have now been shown to be increased in a variety of vascular disorders, the source of these cells have never been definitively shown.

In this study we will test the hypothesis that circulating endothelial cells are derived both from blood vessels and from the bone marrow. We will develop a procedure to stain the Barr body, the inactive X chromosome in mature female cells, within CEC. The Barr body is seen in the interphase nuclei of female cells and represents the inactive X chromosomes. Only cells of females have a Barr body. We will use this fact to distinguish between cells derived from blood vessels and cells derived from the bone marrow in bone marrow transplantation subjects. We will be asking bone marrow transplantation subjects who have had a bone transplant from the opposite sex to be enrolled in this study. We will then isolate CEC from these patients, stain these cells with a Barr body antibody. Assuming we have a man who has received a bone marrow transplantation from a woman, then a CEC that stains with the Barr body antibody implies that it is derived from the bone marrow. A CEC that does not stain with the Barr body antibody implies that this cell is derived from the vasculature. We will classify bone marrow transplant patients into two categories. The first are patients with no other illnesses the second is patients with co morbid conditions such as atherosclerosis, hypertension and diabetes. Previous studies in our laboratory have demonstrated that patients with these co-morbid conditions have increased numbers of CECs. We will be interested in determining if in patients with co-morbid conditions, and increased CEC number have more or less of there CEC derived from the bone marrow.