Creative Biolabs| Lipid-based Drug Delivery
Background The blood–brain barrier (BBB) is a highly complex multicellular structure that protects the brain from harmful substances and invading organisms from the bloodstream, supplying brain tissue with nutrients and controlling its homeostasis. The BBB is composed of polarized endothelial cells connected by tight junctions of the cerebral capillary endothelium and a variety of transporters, which are responsible for its extremely low permeability, limiting the delivery of drugs to the central nervous system (CNS). BBB functionality is dynamically regulated by an ensemble of different cell types, such as astrocytes, pericytes, and neurons. Endothelial cells are surrounded by a basal lamina, which is generally rich in laminin, fibronectin, type IV collagen, and heparin sulfate, representing an interesting target for drug transport and providing a negatively charged interface. The development of new strategies to treat brain diseases is challenging, considering the low drug accessibility to the brain due to the presence of the BBB. In several high incidence brain pathologies, such as stroke, brain infections, Alzheimer’s disease (AD), and Parkinson’s disease (PD), the BBB is altered. Specialized BBB components are more permeable if failed to maintain, allowing the molecules that cause neuroinflammation and neurodegeneration to enter the brain. However, even when damaged and more permeable, the BBB can still be difficult for drug delivery into the brain. Fig 1. Cross-section of a cerebral capillary