Multiple Sclerosis - Emily Corcoran by class project

What body system does Multiple Sclerosis target and how does it target this body system?

classproject00 — 2014-05-05 23:03:31 UTC

Multiple sclerosis directly affects the brain and spinal cord of the central nervous system. This is a neurological condition that has serious implications for remaining organ systems.

This is an inflammatory autoimmune disease in which the insulating myelin sheath coverings are compromised. The nerve cells of the brain and spinal cord contain insulating oligodendrocytes that are wrapped around the axon and responsible form forming myelin sheath. The myelin sheath increases the speed of impulse and result in salutatory conduction. When these cells are destroyed, action potentials are not propagated and communication ceases. Demyelination results in formation of plaques, as it is a form of scar tissue. The plaque forms where the myelin sheath was destroyed and thus disrupts communication. The inability to send or receive impulses manifests itself in a variety of symptoms, both in neurological function as well as other organ system function.

The exact cause of MS is unknown. It is thought to be the reaction of a genetically predisposed individual to a wide range of environmental stimuli. What is known is the role of the immune system and how it mediates this attack on the CNS. Inflammation is caused by T cells passing through the blood brain barrier. Normally lymphocytes of this kind are not able to pass the blood brain barrier, however in the case of MS it becomes pores. This is another area of research for MS. The T cells become sensitized to CNS meylin and mount an attack.

What is the argument made for describing MS as “immune mediated” versus an “autoimmune” disorder?

classproject00 — 2014-05-05 23:04:23 UTC

MS is classified as an autoimmune disorder because the body’s immune system is attacking normal tissue of the nervous system. The immune system attacks and damages central nervous system structures that including the nerve fibers, myelin sheath, and oligodendrocytes.

The term autoimmune denotes a reaction of the immune system against a normally occurring antigen. It’s an attack on the self. In the case of MS, the immune system is attacking a natural occurring antigen or protein as it would a foreign antigen.

However the specific antigen triggering this response remains at large. There is no lynch pin in the causation of MS, not having discovered this antigen leads many to use the classification of an immune mediated disease rather than autoimmune. Genetic and environmental factors have serious implications because they might catalyze the immune response in susceptible individuals.

Sources

classproject00 — 2014-05-05 23:28:53 UTC

University of California - San Francisco. (2014, May 6). "Genome study identifies three possible drug candidates for multiple autoimmune diseases." Medical News Today. Retrieved from
http://www.medicalnewstoday.com/releases/276338.

"Definition of MS." National Multiple Sclerosis Society. N.p., n.d. Web. 05 May 2014.

"Exogenously applied muscle metabolites synergistically evoke sensations of muscle fatigue and pain in human subjects" Exp Physiol February 1, 2014 99: 368-380

"Immune-Mediated Disease." National Multiple Sclerosis Society. N.p., n.d. Web. 01 May 2014.

Demyelination

classproject00 — 2014-05-06 15:11:34 UTC