Carnival of MS Bloggers #9 - Brain Edition

Welcome to the Carnival of MS Bloggers, a bi-weekly compendium of thoughts and experiences shared by those living with multiple sclerosis.

So have you ever planned a party, but hardly anybody showed up?
Well...this week the Carnival received a single contribution by way of the GNIF Brainblogger Blog. I decided to search Brainblogger.com for any posts related to Multiple Sclerosis and include them below. Enjoy.

"Multiple Sclerosis: Nature, Nurture, or Something Else?"
by Lindsey Kay, MD, April 9, 2008

Multiple sclerosis (MS) is a poorly understood disease that affects patients at an early age and, usually, lasts a lifetime. Factors that predispose to the development of MS include genetics, geographic location, sex and birth month, suggesting an interesting nature-nurture interaction in this disease process.

The increased rate of MS at high latitudes has been demonstrated in many studies, with those living in the Northern United States and Canada at a higher risk than those closer to the equator. This geographical influence is most commonly linked to the decreased (UV) radiation in these locations. UV light is a requirement for the production of vitamin D, and it is this effect that is most commonly thought to increase the risk of MS. In addition to affecting bone strength, vitamin D interacts with over 1,000 intracellular pathways, most of which are not well understood. Vitamin D deficiency is documented in patients living at higher latitudes, where MS is more prevalent. Conversely, individuals who work outdoors and have increased sun exposure show a decreased prevalence of MS. Interestingly, the effect of latitude on MS risk is most prominent in infancy in childhood — meaning that moving to an equatorial climate later in life is of limited benefit.

However, a direct link to early childhood vitamin D deficiency and development of MS is lacking, and there are other factors that may cause the same geographical effects. In North America, people of Scandinavian descent are concentrated in the Northern and Western areas, which are the exact locations with the highest MS rates. This suggests the possibility that genetics, in addition to environment, play an important role. Some studies have found South Asian immigrants to Northern climates to have no increased risk of MS, while others find they, or their offspring, to have increased rates of the disease. British migrants to Africa have lower rates than their counterparts who remain in the UK. Clearly there is some interplay between genetic and environmental factors.

There is seasonal variation in the development of MS, based on birth month. Infants born in May have the highest risk, while those born in November have the lowest. This phenomenon may also be explained by exposure to UV light. Women who are pregnant during the winter, and giving birth in late spring, have decrease sunlight exposure compared to those who are pregnant during summer months, suggesting beneficial effects of UV exposure in utero (womb).

Inheritable factors are also present — monozygotic (identical) twins show a higher concordance rate of the disease than non-twin siblings and unrelated persons. In addition to genetic and geographic factors, certain viruses, smoking and female sex are also associated with increased risk of MS.

Clearly we are far from understanding this disease. MS has a variety of seemingly independent factors associated with its development. In addition to the usual suspects — genetics, sex and poor health habits such as smoking — MS is also linked to what appear to be unrelated and uncontrollable factors such as birth place and birth month. The true link underlying all of these factors is currently unknown, but when it is ultimately identified may provide key insights into the pathogenesis and potential treatment pathways of this poorly understood disease.

Reference: Ebers, G. (2008). Environmental factors and multiple sclerosis. The Lancet Neurology, 7(3), 268-277. DOI: 10.1016/S1474-4422(08)70042-5

"Multiple Sclerosis (MS) Linked to Genes"
by Karen Vieira, MBA, PhD, January 26, 2008

Scientists have recently pinpointed genes that can predict who is more likely to get Multiple Sclerosis (MS). MS is thought to be an autoimmune disease, meaning the body attacks itself, and to date it affects approximately 400,000 Americans. Every week about 200 people are diagnosed with this potentially debilitating disease in the US alone. Although the most common image of MS is an elderly individual in a wheelchair, the first signs of disease (periods of dizziness, double vision) often appear in the late teens or early twenties, and twice as often in women. The patient may recover completely, partially, or not at all after this first “relapse” episode, and it is a lifelong disease. Most MS patients will get some permanent disability later on in their lives.

MS is a disease for which we have no cure, because scientists know very little about what causes it. Current treatment options can only modulate the disease or lessen the symptoms. There are generally two streams of thought in the scientific community on what causes the disease: it is either thought to be triggered by the environment, or it is thought that there is a genetic predisposition. Many scientists also propose both factors play a role, given the current evidence. For instance, in Japan, the adoption of a “Western” lifestyle starting in the 1950s has been correlated with a dramatic increase in the incidence of MS. Also, there are statistics showing that the further away from the equator, the higher the incidence rate of MS. It has even been proposed that Vitamin D, which our body produces with the help of sunlight, plays a protective role against MS. It would make sense then, that the sun-intensive equator regions would have a lower incidence of the disease.

Nevertheless, it is now known that genes do play an important role in predicting MS as well. A study spearheaded by researchers from Duke University have found that an important marker in the development and programming of the immune system called the Interleukin 7 alpha receptor (IL-7RA) strongly correlates with MS disease susceptibility. It is now being investigated whether this marker plays a role in causing the disease, providing a valuable clue as to how and why certain people get this illness. Despite the fact that much more research needs to be done, the study provides strong evidence that genetics are an important component, and point the research community in a helpful direction in finding a cure for the disease.

References:
Gregory S et al. IL 7 Receptor alpha chain shows allelic and functional association with multiple sclerosis. Nature Genetics 2007 Sept, 39(9):1083-90.
Broadley SA. Could vitamin D be the answer to multiple sclerosis? Multiple Sclerosis 2007 Aug;13(7):825-6.
Kira J. Multiple sclerosis in the Japanese population. Lancet Neurology 2003 Feb;2(2):117-27. Review

"New MRI Opens New Doors"
by Karen Vieira, MBA, PhD, February 23, 2008

Magnetic Resonance Imaging (MRI) is an important imaging technique used in the medical field to diagnose many diseases and detect abnormalities in the human body non-invasively. In the neurological sense, an MRI is often performed to obtain an inner image of the brain if unusual activity is suspected. For example in the case of multiple sclerosis (MS), abnormal spots called lesions can be detected with an MRI before clinical symptoms occur. MRIs have advantages over other imaging methods because this system is thorough and can be used to detect small subtle changes during the early stages of diseases. One limitation is that the scans usually take several hours to complete.

Now, thanks to dedicated researchers at the University of Illinois in Chicago, the world’s most powerful MRI is ready to be used to help the first patient. The team’s machine received final approval from the Food and Drug Administration (FDA) in the cusp of the 2008 new year. With an entire journal article solely dedicated to the safety of the machine in the Journal of Magnetic Resonance Imaging, the 9.4 Tesla machine will open up a new field in medical imaging, particularly neurology.

Typical clinical MRI scanners have magnetic field strengths of 0.2 to 3 Tesla. At these strengths only the movement of water molecules can be visualized, which limits the observation of metabolic processes in the brain to abnormal cystic or tumor formations and abnormalities in blood vessels or the heart. In 2003 MRIs with magnetic field strengths as high as 8 Tesla were accepted by the FDA, but to date, the 9.4 Tesla scanner is the most powerful clinical scanner that is large enough to acquire images from the human brain.

The 9.4 Tesla MRI allows doctors to visualize molecules other than water. For example, doctors will now be able to perform sodium imaging to determine whether a brain tumor is shrinking, growing, or migrating all in one visit. Previous MRI scanning required that the patient make several trips to the hospital over a period of weeks and sometimes even months. The reason that only one visit is necessary with the 9.4 Tesla scanner is that this high magnetic field strength allows more molecules to be visualized in a shorter period of time in comparison to the lower strength scanners that are currently being used. Imaging technology is now moving towards patient studies such as sodium imaging and towards safety testing for oxygen and phosphorus imaging in humans. Researchers are hoping that this scope can even be extended to other, more rare molecules in the future.

Analyzing a patient’s metabolic pattern after the administration of a therapeutic agent will allow doctors to customize treatment plans as well as determine the optimal type and amount of drugs to prescribe their patients. There are no known harmful side effects of undergoing an MRI besides the exposure to magnetic fields which should be avoided during pregnancy. Patients undergoing an MRI procedure sometimes experience mild nausea or claustrophobia from being inside of a chamber.

Currently MRI is the preferred imaging technique in diagnosing and monitoring diseases such as stroke, tumors, blood vessel abnormalities, infections, Multiple Sclerosis, and many other neurological and non-neurological diseases.

Reference: University of Illinois at Chicago (2008) World’s Most Powerful MRI Ready To Scan Human Brain. ScienceDaily.

And that concludes the 9th edition of the Carnival.

The next Carnival of MS Bloggers will be hosted here on May 8, 2008. Please remember to submit a post (via email) from your blog of which you are particularly proud, or which you simply want to share, by noon on Tuesday, May 6, 2008.

Thank you.

Comments for this post.