For many patients, multiple sclerosis is a chronic disease that they live with but of which they understand very little. It is a chronic disease that has a variety of symptoms that are unique to the individual. The exact origin is not well understood, but scientists believe the disease is caused by a variety of factors. New research into the subject has revealed new insights into the cause, such as location, vitamins, and microbiota. Health professionals hope that this new insight will help find new avenues of treatment.
Multiple Sclerosis Overview
Multiple sclerosis, otherwise known as MS, is a chronic, degenerative immune-mediated inflammatory disease of the central nervous system (CNS). It is characterized by the inflammation, demyelination, and axonal degeneration of the CNS. Women are twice as commonly affected as men, most often between the ages of 20 to 40 years old. People in warmer climates are more likely to be diagnosed than people in colder climates.
Sensory and motor symptoms are most common. A common symptom is optic neuritis, which describes the impaired vision and colored blindness, often in one eye, and often only lasting for a few weeks to months. Other common sensory symptoms include shooting electric sensations traveling down the spine with neck flexion, loss of vibration and fine touch sensation, numbness, and bowel and bladder dysfunction. Common motor symptoms include spastic upper extremities, difficulty walking, difficulty with speech, and tremors. Some patients may possibly experience changes in mentation, like changes in memory.
Multiple Sclerosis Pathogenesis
MS is an immune disease, meaning it is caused by some type of trigger that causes an immune cascade. Scientists believe they understand most of the cascade, but do not know the exact triggers. The prevailing theory is that some trigger activates T-lymphocytes, an important immune cell, which then activates inflammatory processes, causing axonal demyelination. This then results in the loss of axons, scarring, and inadequate healing of the CNS.
Scientists believe MS is caused by some genetic factors and some environmental factors. Their difficulty lies in understanding the environmental triggers. These environmental triggers include ultraviolet radiation, insufficient vitamin D consumption, cigarette smoking, a virus that often causes mononucleosis, gut microbiota, and melatonin differences. Four factors, latitude, vitamin D, melatonin, and gut microbiota, were recently examined as a part of new mechanisms.
Latitude and Sunlight
Almost 85% of the world lives at latitudes between the 40th parallels North and South. This means that they receive much more sunlight than the other 15% who live in the northern United States, Europe, Canada, Russia, or southern-most locations in New Zealand, Tasmania, and Patagonia. Studies have found that people who live in sunnier locations twice as likely to have MS as those who live in less sunny locations. Specifically, 110 to 140 cases per 100,000 people who live in between the 40th parallel will get MS compared to 57 to 78 per 100,000 who live in the northern and southern-most areas of the globe.
Melatonin is linked to darkness and sunlight. It is a molecule that is released from the pineal gland in response to darkness. Melatonin levels are inversely related to MS severity. That means that less melatonin corresponds to more severe MS. Because less melatonin means that there was less darkness and therefore more sunlight, sunlight is again related to MS.
The microbiome is the composition of bacteria in the gut. Most people are born with no microbiome and get their first microbes from their mothers. They then begin to get microbes from their environment and diet. Some microbes in the microbiome are helpful to humans and some are harmful. Normally, helpful and pathogenic microbes can co-exist in the human body without causing problems. However, any type of disruption, like an infection, antibiotics, or diet issues, can upset that careful balance.
Some studies have suggested that microbiota could correspond to MS. For example, studies have noted that increased levels of gram-negative bacteria found in children with MS could be correlated with neurodegeneration. They have also found that certain gut bacteria can affect the blood-brain barrier, an important barrier between the brain and the rest of the body.
MS is a neurodegenerative disease more common in women ages 20-40 in sunnier climates. Scientists have a prevailing theory on how MS works, but they do not fully understand the trigger. They believe there are a number of genetic and environmental factors that influence MS. Sunlight, melatonin, and the gut microbiota are all factors that could be a factor in developing MS. Contact the Stem Cell Transplant Institute to learn more about MS and your health goals.