Multiple Sclerosis Overview Multiple sclerosis or MS is a chronic and progressive disease of the central nervous system, including the spinal cord and brain. The exact cause is not known but thought to be the result of genetics plus environmental factors. While MS is not curable, there are medications that can help slow progression. MS is autoimmune, meaning a disease in which the body mistakes its own healthy cells as foreign cells that need to be destroyed. In Multiple Sclerosis the immune cells attack the myelin sheath surrounding the nerve fibers. The myelin sheath is the insulation that surrounds the nerves and allows the messages between nerves or “nerve impulses” to move faster.  As the disease progresses, the nerves become perminately damaged and communication between the brain and body is hindered. Brains of patients with MS show infiltration of T cells and macrophages, along with myelin breakdown and degeneration of axons. The typical onset of symptoms occur from age 20-50 but can develop at any age. Around 30% of patients will develop a significant disability that affects everyday life within 20-30 years from onset.  Around 400,000 people in the United States and 2.5 million people worldwide are diagnosed with MS. With women 3x as likely to develop MS than men.

MS is a disease of the nerves in the central nervous system or CNS. The CNS which consists of the brain and spinal cord, is needed for the input and coordinated from and to all other areas of the body. When the CNS is not functioning properly many systems in the body are affected. MS is thought to be the result of an autoimmune trigger that causes the body to activate the immune system. Once this trigger occurs inflammatory components of the immune system such as cytokines are able to enter the CNS, which is usually blocked by the blood brain barrier. The blood brain barrier is the body’s way of protecting the CNS against molecules that are not supposed to enter. This leads to inflammation, demyelination, and axonal destruction in the CNS. Demyelination is the breakdown of the myelin sheath surrounding the nerve fibers that is used to protect the nerves and allows nerve impulses to move faster. Myelin is basically the same thing as insulation that coats electrical wires.  When it becomes damaged, the nerve fibers become exposed and the electrical messages traveling down or up the nerve fibers can become diminished. It is important for nerve impulses to move quickly in order to carry messages to and from the CNS and body.

MS is a condition that can progress consistently or sporadically through cycles of exacerbations (when the condition is acute) and remissions (where there are hardly any evidence of the disease). In exacerbations new symptoms can develop over several days or weeks and then often resolve themselves in part or in whole. During remission, the patient has no symptoms for many months or years.  The rate at which the disease progresses varies from person to person. 4 Main Types of Multiple Sclerosis Relapsing- remitting: Most common form of MS, accounts for 85% of all cases. Patients experience acute exacerbations, that may or may not leave permanent damage and disabilities, followed by periods of remission. Progressive- relapsing: MS that is consistently getting worse and includes periods of acute episodes Secondary progressive: Begins as relapsing remitting, but then progresses to a constant steady decline without remission phases. Around 60-70 percent of individuals who have relapsing-remitting multiple sclerosis will go on to have secondary progression. Primary progressive: Steady decline in medical health without periods of exacerbations and remissions

Exact causes of MS are still elusive but both genetic and environmental factors have been attributed in the etiology of MS. Genetics : Genome wide association studies (GWAS) have uncovered over 100 genetic loci associated with MS, accounting for ~30% of the disease risk. Majority of these genes belong to the immunological pathways. Among these, human leukocyte antigen HLA-DRB1*15.01 is the most significant genetic susceptibility locus for MS and may increase in the MS risk by threefold. MS has an overall familial recurrence rate of 20%. The concordance rate among monozygotic twins is 24-30% and in dizygotic twins is 3-5%. In addition to siblings, MS is also prevalent in first and second degree relatives. Environmental factors : Smoking, low Vitamin D levels, and Epstein–Barr virus (EBV) infection are the best-known environmental factors contributing to MS. Smoking: Cigarette smoking has shown to increase the risk of autoimmune diseases including MS. Duration as well as intensity of smoking independently increase the risk of MS.  Smokers are twice as likely to develop MS in comparison to non-smokers. Moreover, passive smoking also increases the risk of MS. EBV: A significant number of patients with MS show EBV responsive antibodies in their serum. Moreover, EBV-specific CD8+ T-cell responses are significantly higher in patients with MS than in healthy volunteers.

MS can be acute, affecting all activities of daily living or it can go into remission so that the patient has no symptoms at all. Common symptoms of multiple sclerosis include: Blurred, double, and even loss of vision Weakness or numbness Pain or tingling it various parts of the body, often arm or leg Stiffness and spasticity with movement Dizziness Loss of coordination and decreased balance, which leads to unsteady gait Fatigue, emotional changes, depression Bladder and bowel function issues Weakness Cognitive changes,