Blood Brain Barrier in Multiple Sclerosis

What is the Blood Brain Barrier?

You have probably heard someone mention the Blood Brain Barrier, (BBB) when speaking on the topic of Multiple Sclerosis but really didn’t understand what that meant.  MS is considered to be an auto-immune disease meaning our body attacks the myelin which is the covering of the brain and spinal cord. It is also considered a neurodegenerative disorder which is caused by a compromised blood brain barrier.

The BBB is tightly wrapped endothelial cells that protect the brain’s capillaries. If you will, think of it as a strainer with many tiny holes in it only allowing small particles, fluid through it. As with the blood brain barrier, the endothelial tissue has small spaces between each cell allowing only certain things to go through it such as fluid, glucose, some gases, and amino acids which are proteins that the blood has already broken down.  Even though all our organs have endothelial cells, the brain differs from the other organs by keeping a tight junction between each cell and having no detectable transendothelia pathways.

This was discovered about 100 years ago by Paul Ehrlich when he injected to the blood stream of an animal and all the tissues of its body turned blue except for the brain and spinal cord. It took 70 additional years for a man named Reese to identify the localization of the barrier to be the capillary endothelial cells in the brain. All of brain areas do not have the barrier though which are located primarily in the midline of the ventricular system and referred to as the CVO’s or circumventricular organs; some of these include the Pituitary and Pineal Gland. The major point of the barrier though is to protect the brain from bacteria, toxins, hormones, and other things that could cause brain infections and other injuries.  Astrocytes are essential makeup of the blood brain barrier and it supports the endothelial cells by providing nutrients, maintenance of extra-cellular ion balance, and repairs the brain and spinal cord following a traumatic injury. The function of the BBB is to protect the brain from foreign substances, protects from hormones and neurotransmitters in the rest of the body, and to maintain a constant environment for the brain. Some things that can break down or weaken the barrier is high blood pressure, not fully formed at birth, high concentration of substances in the blood that can push through the barrier, exposure to radiation, infectious agents, and brain injury.

When a weakness occurs in the barrier, it usually means the P-glycoprotein is not working. This is an important protein that pumps many foreign substances out of cells. With Multiple Sclerosis, this weakness allows a certain type of white blood cell called T lymphocytes to cross over and attack and weaken the myelin. This breaks down the myelin causing the scarring and lesions to form thus blocking nerves transmission to and from the brain causing our many symptoms.  Antioxidants may help to stabilize weakening BBB, so research is being performed to see if treatments to help with this process can work with people who have MS.

A great deal of information has come from ongoing research with Multiple Sclerosis and several new treatment, therapies, and ideas have sprung up over the years. We have come a long way since my diagnosis in 2004 and can believe researchers are close to finding out why we get this disease and ways to catch it early, and my prayer is that a cure is not far away.

MS Blogger and Multiple Sclerosis Activist shares her journey living with MS, tips for others living MS and her husband, Steve, offers his insight as a caregiver for MS.