Angiogenesis allows for oxygen, nutrients, inflammatory cells, cartilage, and bone progenitor (precursors) to reach the site of regeneration.[22] Animal models that enhanced angiogenesis also showed enhanced regenerative abilities. Angiogenesis is also temporally significant for bone regeneration.[23] It has been shown that osteoblasts that originate from vascular endothelial growth factor (VEGF) signaling play a crucial role for the development of new bone during regeneration.[24] VEGF is also a key regulator of angiogenesis.