Platelet alpha granule (α-granule)

Platelet alpha granules are the most abundant type of secretory granule in platelets, comprising about 50–80 per cell and accounting for approximately 10% of platelet volume[5][6][7]. They are membrane-bound organelles, 200–500 nm in diameter, containing a wide array of proteins, including growth factors (e.g., platelet-derived growth factor, vascular endothelial growth factor), clotting factors (e.g., fibrinogen, factor V, von Willebrand factor), chemokines (e.g., platelet factor 4, interleukin-8), adhesion molecules (e.g., P-selectin, fibronectin), and complement proteins[1][4][5][6][7]. Upon platelet activation, they release their granular contents to mediate blood coagulation, promote wound healing, modulate inflammation, and support angiogenesis. Dysfunction or deficiency of alpha granules, such as in gray platelet syndrome, leads to bleeding disorders and dysregulated hemostatic response[1][5][7].

Other names

alpha granuleα-granuleplatelet α-granuleplatelet alpha-granule