Table 1.

Main classes of substances present in platelet granules and cytosol.

Alpha-Granules

Growth and angiogenic factors   (e.g., platelet-derived growth factor, fibroblast growth factor, vascular endothelial growth factor, connective tissue growth factor, epidermal growth factor, transforming growth factor β, insulin-like growth factor 1)

Cytokines and chemokines   (e.g., interleukin-1β, CD40 ligand, CCL2, CCL3, CCL5, CXCL1, CXCL4, CXCL12, CXCL16, platelet factor 4)

Adhesion molecules   (e.g., P-selectin, fibronectin, vitronectin, von Willebrand factor)

Coagulation factors   (e.g., factors V, XIII, von Willebrand factor, high-molecular-weight kininogen, fibrinogen)

Anticoagulation factors   (e.g., tissue factor pathway inhibitor, protein S)

Fibrinolytic factors   (e.g., plasmin, plasminogen)

Antifibrinolytic factors   (e.g., α2-antiplasmin, thrombin activatable fibrinolysis inhibitor, plasminogen activator inhibitor-1)

Other molecules   (e.g., albumin, calcitonin, angiotensinogen, thrombospondin)

Dense granules

Serotonin   Histamine   Adenine nucleotides (ADP, ATP)   Cations (e.g., calcium, magnesium), polyphosphate   Adhesion molecules (e.g., P-selectin)

Lysosomal granules

Cathepsin D, E   Carboxypeptidase A, B   Acid phosphatase   Arylsulfatase

Cytosol

Adhesion molecules   (e.g., P-selectin, fibronectin, vitronectin, fibrinogen, thrombospondin, von Willebrand factor)

Coagulation factors   (e.g., factors V, von Willebrand factor)

Platelet activators   (e.g., platelet-activating factor, TxA2)

Vasoconstrictors   (e.g., TxA2, 12-hydroxyeicosatetraenoic acid)

ADP—adenosine diphosphate; ATP—adenosine triphosphate; GP—glycoprotein; TxA2—thromboxane A2.