The blood-brain barrier plays a vital role in protecting the brain from blood-borne disease and toxic compounds.
Like a security detail guarding the life of a public figure, the blood-brain barrier is vigilant in defending against intruders while allowing access to the select few. Molecules crucial to brain functions, such as oxygen and glucose, enter the brain, whereas toxins and most pathogens are turned away.
For diseases of the central nervous system, it is essential to get treatments across this barrier and delivered to the specific target within the brain where the treatment is needed most. Unfortunately, the power of the blood-brain barrier to protect us from harm means that delivering therapeutic drugs to the brain is exceptionally challenging. In fact, more than 98 percent of small molecule drugs and nearly 100 percent of larger biologic drugs (antibodies and enzymes) cannot enter the brain at sufficient concentrations to cause therapeutic effects.
The delivery of medicine across the blood-brain barrier has been the single greatest challenge in the treatment of hundreds of common and rare neurological diseases. For generations of people suffering from brain cancers, neurodegenerative diseases and metabolic disorders, the blood-brain barrier represents a wall separating patients from effective treatments and hope.