THYMIDINE PHOSPHORYLASE, 2-DEOXY-D-RIBOSE AND ANGIOGENESIS

Angiogenesis is the term used to describe the formation of new blood v essels from the existing vasculature. In order to attract new vessels, a tissue must release an endothelial-cell chemoattractant. 2-Deoxy-D- ribose is produced in vivo by the catalytic action of thymidine phosph orylase (TP) on thymidine and has recently been identified as an endot helial-cell chemoattractant and angiogenesis-inducing factor. TP, prev iously known only for its role in nucleotide salvage, is now known to be angiogenic. TP expression is elevated in many solid tumours and in chronically inflamed tissues, both known areas of active angiogenesis. There is evidence that TP is also involved in physiological angiogene sis such as endometrial angiogenesis during the menstrual cycle. The m ajority of known endothelial-cell chemoattractants are polypeptides th at bind to endothelial-cell-surface receptors. In contrast, 2-deoxy-D- ribose appears to lack a cell-surface receptor. Glucose is another sug ar that acts as an endothelial-cell chemoattractant. The migratory act ivity of glucose is blocked by ouabain. It is possible that 2-deoxy-D- ribose and glucose stimulate endothelial-cell migration via a similar mechanistic pathway.