Angiopoietins are part of the vascular endothelial growth factor (VEGF) family and play a role in embryonic and neo-vascularization. Angiopoietin cytokines regulate microvascular permeability, vasodilation, and vasoconstriction by signaling to the surrounding smooth muscle cells. Angiopoietin-1 (ANG-1) is encoded by a gene that produces a 498 amino acid peptide with a molecular weight of 57 kDa. It can form dimers, trimers, and tetramers. ANG-1 plays an important role in vascular maturation, adhesion, migration, and survival. Studies have shown an increased ratio of ANG-2 to ANG-1 in the serum, indicating dysregulation of the angiopoietin and tyrosine kinase pathway, which is common in blood-related diseases such as diabetes, malaria, sepsis, and pulmonary arterial hypertension.