Tissue Growth Factors

Insulin-like growth factor 1 (IGF-1)

Somatomedin C

synthesized predominantly by growth hormone-influenced hepatocytes

does not directly stimulate angiogenesis

The key growth factors that promote angiogenesis in neoplastic and granulation tissue are vascular endothelial growth factor (VEGF) and fibroblast growth factor.

Proinflammatory cytokines (e.g IL-1, IFN-gamma) can indirectly promote angiogenesis through increased VEGF expression.

The laminin in basement membrane may pose a physical barrier to the sprouting of new blood vessels.