Microbiome Bites December 4th: The microbiome plays a causal role in neurodegenerative disease.

Microbiome involvement in Parkinson's disease | ThinkBiome

There have been some big breakthroughs in microbiome research this week:

1. Gut Microbes Linked to Neurodegenerative Disease

Here’s some great research on the gut-brain axis.

Parkinson’s Disease affects 1 million people in the US and up to 10 million worldwide, making it the second most common neurodegenerative disease. Many patients with Parkinson’s disease experience digestive symptoms like constipation years before they develop neurological symptoms, and scientists have found dysbiosis in the gut microbiomes of patients with Parkinson’s disease.

In a study published in the journal Cell, a team from Caltech demonstrate that gut microbiota promote neuroinflammation and motor deficits in a mouse model of Parkinson’s disease. The study is not simply correlative, but shows that the gut microbiome appears to play a causal role in neurodegenerative disease. The team found that they could induce Parkinson-typical symptoms in mice by transferring bacteria from Parkinson’s patients into those mice. The researchers believe this finding has significant implications for the treatment of Parkinson’s disease.  Current treatment approaches involve trying to get a drug into the brain, which is difficult. However, if Parkinson’s disease is not solely caused by changes to the brain, but instead changes to the microbiome, them targeting treatments to the gut is much simpler.

You can read an in-depth overview here. The study is here (pdf).

2. Early life history and genetics may play crucial role in shaping gut microbiome

How is a persons’ microbiome formed?

Which is more important to the development of a persons' microbiome, nature or nurture?

These are some of the fundamental questions scientists are seeking answers to.

According to research published in the journal Nature Microbiology, genetics and birthplace have a big impact on the make-up of the gut microbiome. Researchers from Lawrence Berkeley National Laboratory found that the genes in mice that were correlated to microbes in the gut are very similar to genes that are involved in many diseases in people. Furthermore, moderate changes in diet influence exactly what functions the microbes in the gut perform. The team believes that because of this finding, in future, we could design microbiome-optimized diets to digest food more effectively or modulate susceptibility to disease.

Here’s a more in-depth overview. Here’s the original research article (pay wall).

3. Disrupting the daily routine of the gut microbiome can be bad news for the whole body

In a study published in the journal Cell a group of scientists from the Weizmann Institute in Israel have used some remarkable DNA technologies to show that the gut microbiota of mice changes location within the gut, and changes its metabolic outputs (postbiotics) over the span of a 24-hour day. Vitamins, lipids and amino acids that the gut microbiome makes throughout the day circulate in the mouse’s blood. As the levels of these products changed throughout the day, they altered the expression of genes in the mouse’s liver encoding metabolic enzymes. This is the first clear demonstration of the gut microbiota changing the circadian activity (daily rhythm) of a major organ that is fundamental to health.

Evan more interestingly, the researchers found that the liver changes how it responds to an overdose of acetaminophen over the span of the day in response to signals from the gut microbiota. An overdose of acetaminophen was less toxic at dawn and most toxic at dusk. This means that the time of day that a medication is administered could have a big impact on its effectiveness, and on the severity of its side effects.

Here’s a great overview at the conversation. The study is here.