Joyce Bischoff

My lab studies the role of endothelial cells and pericytes in various settings of vascular disease and in the normal repair of the vasculature. Here I describe the four areas we are pursuing.

• Infantile hemangioma is a vascular tumor that can grow rapidly, causing organ damage, disfigurement and morbidity. We’ve focused on identifying cellular mechanisms that drive this uncontrolled vascular growth. We identified a multi-potent stem cell that can recapitulate hemangioma in immune-deficient mice. We are also studying pericytes from hemangioma and the glucose transporter-1 positive endothelial cells, which are a hallmark of hemangioma. Our goal is to use cellular and animal models to identify new drugs that will work safely and quickly to prevent hemangiomas from growing to an endangering size.
• Vascular malformations are distinct from ascular tumors such as hemangioma but are also little understood and medical therapies are needed. We have recently begun new projects on the cellular and molecular basis of capillary malformations, lymphatic malformation and venous malformations.
• Endothelial progenitor cells (EPCs), also called endothelial colony forming cells (ECFCs) are rare cells found in the blood. They can be isolated based on their high proliferative capacity in vitro. We demonstrated the usefulness of EPC/ECFC for endothelializing small diameter vascular grafts in a sheep model and for building networks of human blood vessels rapidly in vivo using athymic nude mice. We also showed that ECFC were able to assemble into perfused vessels when injected into ischemic rat myocardium, and that the presence of these cells was beneficial to recovery of heart function over time.
• Heart valve endothelial cells - The endothelial cells lining heart valves exhibit unique plasticity compared endothelial cells of large vessels (veins and arteries) or microvessels (capillaries). The valve endothelial cells can undergo endothelial to mesenchymal transition (EndMT) in response to TGFβ, and this process is highly regulated. We study the mitral valve endothelium as part of a multi-disciplinary team focused on how the mitral valve adapts after myocardial infarction.