PERIPHERAL-BLOOD PLATELETS EXPRESS VEGF-C AND VEGF WHICH ARE RELEASEDDURING PLATELET ACTIVATION

VEGF-C is a recently characterised endothelial growth factor structura lly related to vascular endothelial growth factor (VEGF). We stud led the expression of VEGF-C and VEGF in the cells of peripheral blood and in the umbilical cord blood CD 34+ cells, representing haematopoietic progenitor cells. Expression of VEGF-C was detected in the CD34+ cell s. In peripheral blood VEGF-C mRNA was restricted to platelets and T-c ells. In contrast to the expression pattern of VEGF-C, VEGF mRNA was d etected in all peripheral blood cell fractions studied, and also in CD 34+ cells. VEGF-C mRNA was also detected in fresh bone marrow samples of acute leukaemia patients, but the expression did not show lineage s pecificity. VEGF-C and VEGF polypeptides were present in platelets and they were released from activated platelets together with the release of P-thromboglobulin, suggesting that VEGF-C and VEGF reside in the c i-granules of platelets. VEGF-C and VEGF, released from activated plat elets, may have a role in angiogenesis during wound healing, and possi bly also in other pathological conditions, such as atherosclerosis, tu mour growth, and metastasis formation.