Does gut flora cause multiple sclerosis?

Multiple sclerosis is insidious, unpredictable and incurable. But how does it develop? The composition of our intestinal microbiome could be the key, researchers have discovered in a study of twins.

Just looking at the two women, you might find it difficult to tell them apart: Lisa and Julia Ngo are identical twins. Yet there is a major difference in their health: Lisa suffers from multiple sclerosis (MS), Julia does not.

That made the sisters ideal volunteers for a study at the Ludwig Maximilian University in Munich into how MS develops. 

"I want to know where MS comes from," Lisa told DW. Sometimes I ask myself, why did it hit me? Do I have the wrong lifestyle? Is it that what triggered the outbreak? So I took part in the study."

A multifaceted disease

MS, an autoimmune disease, is the most common inflammatory disease of the central nervous system.

Science | 17.07.2018

Immune cells attack the brain and spinal cord, the body turning against itself. The myelin sheath — a layer around the nerve roots that is essential for transporting electric signals — is destroyed, meaning nerve stimuli are no longer transmitted and the body becomes paralyzed. 

Read more: Germany allows MS patient to grow cannabis in unprecedented case

 Zwillinge Lisa und Julia - MS

Twins Lisa and Julia Ngo look very much alike, but only Lisa suffers from MS

Progression of the illness and symptoms vary widely among MS patients. They range from a paralysis of the legs to visual disturbances. While some people with MS have little or no disability, others will eventually need a wheelchair. There is no typical MS case.

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Looking for the trigger

Scientists believe the trigger for MS can be found in the intestinal microbiome, which is different in every person, including twins. So, the research team recruited more than 60 pairs of twins for its MS study. In each pair, one twin had MS and the other did not. 

Dr. Lisa Ann Gerdes has led the project from the beginning.

Dr. Lisa-Ann Gerdes

Lisa-Ann Gerdes leads the twin study into triggers for MS

"Identical twins have identical genetic material, and other factors like age, sex and so-called environmental factors — such as nutrition and childhood infections — are alike, too. However, there may be differences in the gut flora," explains Gerdes.

Her team set out to discover what effect intestinal bacteria might have on the development of multiple sclerosis. 

Read more: Algorithm to detect multiple sclerosis developed in India

Of mice and men

The researchers use mice to investigate the relationship between MS and intestinal bacteria.

They provoked an immune reaction in the animals that led to symptoms very similar to those in humans. The mice suffered from paralysis of the hind legs, which regressed, much like MS attacks in humans.

The majority of MS patients suffer from so-called relapsing-remitting MS. A relapse manifests itself as an inflammation in the brain or spinal cord, which can be detected with the help of MRI imaging. How often these attacks occur is different for each patient.

Growing up in quarantine 

Some mice fell ill and others did not. To find out why, the researchers raised the animals in a sterile incubator without any contact to other mice, so there could be no exchange of bacteria.

Infografik Erkrankungen der Myelinscheide ENG

"These mice even had to be born by caesarean section. During natural birth, they would have picked up bacteria from their mother," Gerdes says. 

The isolated mice were then infected with human intestinal flora. Those given microbiota from a twin with MS were more likely to develop brain inflammation typical of the disease — indicating that the composition of intestinal flora could be a trigger for MS. 

Read more: Guillain-Barré syndrome: A sudden paralysis of the arms and legs

Sequencing bacteria

"I had stool samples and blood samples taken," Lisa Ngo reports. "I had to do various tests, including MRIs."

The researchers then analyzed these samples in detail, Gerdes says. "They were not examined under the microscope as we used to do in the past, but with very modern methods."

Sequencing the genetic information contained in the bacteria allows the researchers to determine which are bacteria are present, and what they do.

Early prevention 

"The mouse model enables us to follow the early phase of disease development live," said Gerdes. "This means we can observe that the intestinal system, the immune system and the brain interact."

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Multiple sclerosis and the gut microbiome

This initial trigger is the most interesting phase for the researchers. They want to track down the trigger for MS and follow its progression, step by step.

The immune system receives the wrong command. First it attacks the brain and then a whole cascade of processes start.

"We may not be able to find these initial triggers later on. They may have receded into the background due to therapies or other influences," says Gerdes.

This makes it all the more important to identify the earliest moment in which MS develops.

Hope for new drugs

The most important question for MS patients is whether this helps scientists develop new drugs.

"There is hope that further research into the gut flora in MS patients will help us better understand the mechanisms of the disease," Gerdes says. "We want to develop therapies that might prevent the development of the disease, or stop its progression."

Their best hope is to control the disease as early as possible, and then as far as possible.

Lisa Ngo is keen to be involved. She studied pharmacy for five semesters before switching to molecular sciences. "I would like to develop drugs for MS or work on making MS more tolerable," she says. "That would be my dream."


We're not moving enough

The health of Germans is at its lowest in history, according to a new report that found just under nine percent of the population follow a 'completely healthy' lifestyle. And the problem is a lack of movement. On average, Germans spend 7.5 hours sitting per day. But it's not just them who are leading sedentary lives - the world over, people are spending too much time perched on their behinds.


Is sitting the new smoking?

In recent years, sitting has been dubbed the 'new smoking' because of the seriousness of its public health risks. While not all scientists agree that it should be put in the same category as smoking, over the past 15 years too much time spent on one's backside has been linked to serious health issues, like low blood pressure, poor circulation, cancer, heart disease and diabetes.


Not all sitting is equal

But sitting in the office chair at work is not as strongly linked to long term health risks as sitting watching television is. Spending too much time in front of the telly has been consistently linked to an early death, type 2 diabetes and heart disease.


Frailty on the rise

Women who spend more time sitting down as they age are at higher risk of becoming frail, according to new research from the University of Queensland in Australia. That means they’ll be less likely to recover from illnesses or injuries. But researchers also found the damage could be reversed - so up you hop! It's not too late to reduce the effects of too much time spent on your butt.


Sit less, move more

Scientists say, as your total sitting time increases so does your risk of an early death. But if you sit for less than 30 minutes at a time, you could reduce your risk of kicking the bucket too soon. For every 30 consecutive minutes you sit, try to match it with moving and walking for at least five minutes.


Enter: standing desks

For office workers, sitting seems to be an unavoidable part of the day. Unless, of course, you write those emails on your feet. Adjustable desks that allow a sitting and standing option have become standard in many workplaces around the world. But the research shows they aren't the best solution - because even if you're standing, you don't expend much energy while staying in the one spot.


Huff and puff

Sitting will not undo the benefits of exercise, but the less time you spend sitting down the better. Health experts say it's important for us to move as often as possible, and increase our heartrates in the process - the World Health Organization recommends doing 150 minutes of moderate activity per week or 75 minutes of vigorous activity.