Enhanced permeability and retention effect based nanomedicine, a solution for cancer

Table 1 Unique characteristics and factors involved in enhanced permeability and retention effect

Active angiogenesis and high vascular density

Extensive production of vascular mediators that facilitate extraravasation

Bradykinin

Nitric oxide

Vascular permeability factor/vascular endothelial growth factor

Prostaglandins

Collagenase (matrix metalloproteinases, or MMPs)

Peroxynitrite

Defective vascular architecture, for example, lack of smooth muscle layer cells, lack of or fewer receptors for angiotensin II, large gap in endothelial cell-cell junctions, anomalous conformation of tumor vasculature (e.g., branching or stretching)

Impaired lymphatic clearance of macromolecules and lipids from interstitial tissue (→ prolonged retention of these substances)