How The Gut & The Brain Communicate With Each Other, Interview with Neuroscientist Aya Osman

First, please introduce yourself to our community.

Hey there everyone, my name is Aya Osman and like many of us, I am a multidimensional individual, with interests ranging from the science underlying behavior to the evolution of the fashion industry! I spent most of my 20’s studying and gaining qualifications, eventually getting my PhD and specializing in behavioral neuroscience while simultaneously juggling a career in modelling since the age of 17.

You’re a neuroscientist and model, dispelling the unfair stereotype that models can’t also be ‘brainy’. Have you experienced any judgment first hand and how have you managed to merge the two careers?

Certainly, you face judgments in both the modelling and in the science world, mostly stemming from people failing to comprehend how you can do both things. However, in both industries, I have come across many amazing individuals, from models who have successful careers in law, dentistry, and engineering, to scientists who have successful careers in music, acting and dancing. With time, I have become immune to the judgment that arises out of ignorance or being small-minded and has become more confident in owning who I am with all my various aspects.

I’ve realized as I continue to climb the ranks in both fields and produce work that speaks for itself, the judgment ceases, so now I just focus on pouring all my energy into my work rather than worrying about opinions or judgments.

The two careers have naturally come together over the years as my modelling work has put me in a public-facing position, perfect for science communication. I am surrounded by amazing scientific work being done daily that could be life-changing to many, and so I am using my position to help convey as much of this fascinating scientific information in a way that captures the attention of the public.

Are there any lessons/skills that your work in science has taught you which you’ve been able to apply to modelling and vice versa? 

I sort of touched on this in my previous answer, but being in front of the camera or walking down a runway is super nerve-racking for anyone, especially for a scientist!

It has really helped build my confidence and that has aided me greatly in being able to communicate science openly and confidently to the public. As for skills from the scientific work into the modelling, I would have to say my scientific training has allowed me to develop a way of thinking, analyzing and dissecting topics as well as develop my creative thinking.

I have been taking these skills into the modelling and fashion industry as a whole in several ways, including becoming more heavily involved in creative directing and developing the concepts behind productions/shoots.

Neuroscience also produces a lot of beautiful artistic images from saying RNA scope and other techniques. I have been working with several fashion designers to incorporate some of these scientific images into fashion, I don’t want to give away too much at this stage, but I would definitely say watch this space!

What in particular drew your interest in researching the role of the gut-brain axis?

My Interest in the gut-brain axis really started during my PhD research, I was looking at how exposure to proteins found in both human and cow’s milk called caseins, beyond the ‘normal’ age of weaning, affect the development of the opioid system in the brain (a system which is heavily implicated in regulating mood).

We found consumption of milk caseins for a prolonged period of time in early-life, results in disruption to the normal developmental trajectory of the opioid system and this resulted in depressive-like behavior later in adulthood. How exactly milk caseins which are consumed cause these effects to brain and behavior led us to investigate the connection between the gut and the brain further.

Our results also showed that milk caseins changed the composition of the bacteria found in the gut, causing certain groups to increase and others to decrease. This was when I really started to delve into the gut-brain axis literature and begin designing and running experiments to help further our understanding of the gut-brain axis.

Can you please break down to our readers in simple terms how the gut-brain connection works?

The connection between the gut and the brain was really first confirmed in the 1800s when a Canadian fur-trader was accidentally shot at close range and the surgery he had left him with a fistula in his gut, basically a window into the intestine. From the treatment of this patient, a lot of data was collected, and many observations were made which taught us a lot about the gut. Of interest, it was noted that when the patient became angry or irritable, it affected the rate at which he was digesting food, this hinted at a gut-brain connection.

Since then, we now know the gut and the brain communicate with each other in several different ways including the nervous system (in particular the Vagus nerve), via the production of hormones, via the immune system and now over the past decade, evidence indicates that one of the key players involved in regulating the connection between the gut and the brain are the trillions of microbes within the gut, known as the microbiota and the metabolites they produce.

Using these modes of communication, mood and behavior can influence the gut and similarly anything affecting the gut can also result in changes to mood and behavior.

You recently had your first postdoc paper in Preprint – congrats! Tell us about the research subject and the most interesting conclusions you discovered.

Thank you! So my postdoctoral research is basically investigating interactions between the autism spectrum disorder (ASD) associated gene- Shank3 and the gut microbiome. We choose to study this gene because mutations to this gene result in a condition known as Phelan McDermid Syndrome or PMS, which often manifests with autism.

Actually, PMS is one of the leading known causes of ASD responsible for somewhere between 1-2% of all cases. Next, we choose to study its interaction with the gut microbiome because increasing evidence shows that gastrointestinal issues are very common in the ASD population, from bloating to constipation and diarrhea. Our results, in line with others, show that mutations to the Shank3 gene result directly not only in autistic-like behavior but also to changes to the gut.

We saw a decrease in the diversity of bacteria found in the gut, as well as a decrease in good bacteria known as Lactobacillus. What’s more, the bacteria in your gut are also highly metabolically active, that is they help you digest certain foods like fibers, and they release breakdown products into your bloodstream that are either directly neuroactive or that help build neurotransmitters needed in your brain, or affect which genes are expressed in your brain. One class of such metabolites produced by gut bacteria, called short-chain fatty acids or SCFAs were affected due to the Shank3 mutation in our study, and SCFAs have previously been shown to directly influence behavior.

So, in summary, seeing such changes outside of the brain caused by mutations to a gene, helps us identify targets we can try to modify to improve symptoms of ASD. Our results so far build a case for targeting either the gut microbiome or its metabolites in the treatment of ASD.

Research has revealed that the gut microbiome and the brain communicate with each other via the immune system. What is the significance of this and what could it mean for the future treatment of mental disorders?

The gastrointestinal tract has the densest concentration of immune cells in the body, due to the trillions of microbes that live in our gut. These microbes play a huge role in priming our immune system to identify potentially harmful pathogens.

Along with priming our innate immune system, the microbiota can influence the numbers, migration and function of various immune cells including helper T cells and regulatory T cells and Microglia, while also influencing the of the release of cytokines and chemokines by these immune cells.

Cytokines and Chemokines are basically chemical messengers involved in recruiting other immune cells to the vicinity and the repair of damaged tissue. Cytokines, in general, are classified into two categories, pro-inflammatory and anti-inflammatory, which basically either cause inflammation or reduce/stop inflammation. The balance between pro and anti-inflammatory cytokines is essential for homeostasis in our bodies. If the balance of bacteria in our gut changes for whatever reason and we now have more bacteria in there which cause immune cells to release pro-inflammatory cytokines, that can result in dysregulation to normal immune homeostasis.

Many mental disorders such as addiction or depression present with issues related to inflammation, or an increase in inflammatory markers. Research has highlighted the role of immune cells found in the brain called Microglia in many mental disorders. These microglia can be looked at as police patrolling our brains looking for any intruders, they are usually inactive but once activated they too can release cytokines which can recruit immune cells from outside the brain to aid in defence, they can also regulate neurotransmitter release from neurons, therefore, having an influence on behaviour. Recently it was determined that microbiota in the gut are necessary for the maintenance and maturation of microglia in a healthy and functional state. That is to say, microglia function is influenced by gut microbial activity.

The SCFAs produced by gut bacteria which I mentioned earlier has also been shown to directly interact with microglia in the brain influencing their shape size and numbers. This is of importance to mental disorders such as depression which has been described as a microglia-associated disorder. This has massive implications for the treatment of these mental disorders because it gives us things we can target outside the brain (the gut microbiome) to help influence what’s going on inside the brain and subsequent behavior. The immune system and microglia have huge implications for the treatment of mental disorders in the future.

What is your hope for the future of microbiome research? Are there any other particular areas you’re personally excited to dig deeper into?

My personal hopes for the future of microbiome research is that we better our understanding of the bacterial populations present within us, with such large numbers of bacteria the characteristics and functions of many bacterial groups are yet to be discovered.

The human microbiome project is making great progress in this aspect. The more we know about this ecosystem living within and on us the more we can determine what influence it has on our health and how we can manipulate it in the treatment of disease. For me personally, the immune system (in particular microglia), gut microbiome and its link to ASD as well as other neuropsychiatric disorders such as drug addiction are areas, I look forward to digging deeper into over the next few years.

Has the knowledge you’ve gained as a neuroscientist impacted the way you lead your life in terms of adopting a particular lifestyle or healthy practices? 

Our minds and bodies are truly fascinating, and my respect for our bodies and life, in general, grows daily as I continue my journey in neuroscience and academia as a whole, ask me this question again in 10 years’ time and I could probably write a book or two on it! But yes, you do inadvertently pick up on information that if implanted correctly, can influence your life for the better.

One thing my research over the last few years has highlighted is to be careful and considerate of what I put in my body. Food not only influences your gut bacteria but also becomes your building blocks, and we need a good balance of everything to function, think and behave properly. Hippocrates a Greek physician said, “Let food be thy medicine and medicine be thy food.”  

And finally, what advice would you give to young women who are considering pursuing a career in science but are perhaps intimidated by entering a male-dominated profession?

Honestly, my advice is fortune favors the brave! We need as many minds as possible working to advance our knowledge of life. If science is what tickles your fancy, go ahead, and pursue it shamelessly and relentlessly. The main thing to keep in mind Is persistence and focus always pay off no matter the challenge at hand. 

Over the years I have also realized what valuable assets women are to any workforce, honestly girls, we are amazing and capable of so much and I hope we continue to realize this! Males and females are different and we each bring different ways of thinking and operating to the scientific field. If you always keep in mind your uniqueness and what you as an individual bring to the table, you will never be intimidated no matter if it’s a male or a female-dominated industry you are entering.

The above content is provided for informational and educational purposes only and is not a substitute for professional advice or diagnosis and should never be relied upon for specific medical advice. moxie shall not be liable for any claim, loss, or damage arising out of the use of, or reliance upon any content or information in this article.

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