Identification of haptoglobin as an angiogenic factor in sera from patients with systemic vasculitis.

摘要: Angiogenesis is an important process in chronic inflammatory diseases. We observed that sera from patients with systemic vasculitis stimulated angiogenesis vitro model using human umbilical vein endothelial cells cultured on a basement membrane (Matrigel) substrate. After 40% ammonium sulfate precipitation, angiogenic activity remained the low molecular weight fraction and could be inactivated by heat. SDS-page of serum FPLC fractions exhibiting maximal demonstrated two prominent species 45 16-20 kD patients' sera. These bands were much less apparent obtained control subjects. Amino-terminal sequencing 45-kD protein it was haptoglobin. Purified haptoglobin dose-dependent manner. The partially inhibited antihaptoglobin antibody. Furthermore, levels correlated both disease activity. Haptoglobin confirmed vivo models implanted disc subcutaneous injection membrane. Stimulation newly recognized biological function increased found conditions may play role tissue repair. In vasculitis, might also compensate for ischemia promoting development collateral vessels.