Tackling the Blood Brain Barrier

The blood brain barrier (BBB) is a tried and true protection for the brain from all sorts of chemicals and other molecules that are in the blood.  Brain capillaries shelter the brain by forming a highly selective permeable layer that limit transport via membrane carriers and channels(2).  The lipophilic membrane keeps water soluble molecules without membrane carriers or channels from crossing the barrier and into the brain.  Early anti-histamines were lipid soluble and freely and easily crossed the BBB causing unwanted drowsiness in patients taking these drugs.  By changing the structures of these anti-histamines, making them less lipid-soluble, non-drowsy allergy medicines were developed(2).

Neurobiologists from Genentech in South San Francisco have developed an antibody capable of crossing the BBB and help limit the damage done by Alzheimer’s disease (AD).  The damage to neural function due to AD is caused by the aggregation of protein amyloid-β(1).  Amyloid-β is created by an enzyme called β-secretase 1 (BACE1).  The antibody developed by Genentech binds to an iron transporter called transferrin that typically carries iron across the BBB.  The antibody binds to transferrin, is transported across the BBB and then binds, with a higher affinity, to BACE1, blocking amyloid- β production(1).  Recent studies have shown decreases in plasma levels of amyloid- β up to as much as fifty-percent in mouse and monkey models.

As technology progresses, so will the treatment of pathologies that we previously viewed as death sentences.  As future health care workers, we will be using techniques and ideas that we now only have limited understanding of.  I am very excited to see where medicine will go, but at the same time I have to worry if the technology may ultimately pass me by.  In this career path, we will always be learning and will always be working to provide the best and most successful treatment options for our patients.

Silverthorn DU. 2010. Human Physiology: An Integrated Approach. 5^th ed. California: Pearson Education, INC. 303-305 p.

Reardon S. 2014. Alzheimer's drug sneaks through blood–brain barrier. Nature Publishing Group. Available from: http://www.nature.com/news/alzheimer-s-drug-sneaks-through-blood-brain-barrier-1.16291