Hey Brainiacs,
Welcome to this week’s newsletter! We’re going to delve into some of the ground-breaking scientific research being done on ‘mini-brains’ and ‘mini-colons’.
‘Mini-Brains’ and ‘Mini-Colons’
These so-called ‘mini-brains’1 and ‘mini-colons’2 are actually known as organoids. Organoids are lab-grown cells that resemble an organ in the cells they contain, their structure, and their function!
The key thing to understand here is they are not organs, but, they do recapitulate a lot of the complexities seen within human organs. This can be incredibly useful in trying to understand and treat different diseases, such as cancer, and when trying to understand basic biology about how the human body functions. Organoids are especially crucial when a human disease cannot be modelled in animals. And there are a lot of reasons we cannot use animals to model humans, like differences in genetics.
How does one make an organoid? Good question. Organoids start out as stem cells3. Let’s start out with the cell part of that, and revamp our GCSE knowledge. A cell is the smallest building block of life; they make up all our organs, our skin, our bones, everything. Each human body is made up of nearly 37 trillion cells4.
Now let’s get into the stem part of stem cells. Broadly speaking, there are two types of cells. We will call them ‘baby’ cells and ‘adult’ cells. Baby cells can become anything they want- liver, heart, brain, bone- the world is their oyster! They’ll decide what to become based largely on their environment. Adult cells already have their life’s purpose, they know they’re a liver cell or a brain cell. So, by that logic, ‘baby’ cells can become any ‘adult’ cell. And baby cells are known in the science world as stem cells5! Given the right environment, a stem cell can become any type of cell. Scientists have used this knowledge to put stem cells into the appropriate environment for their desired organoid, and voila6! Of course, this process is much more complex than I am making it out; in fact, it can take months to grow an organoid6.
We know what stem cells are, we know how they’re used to get organoids. But are they any good?
Well, let’s take a look.
This brain organoid has been stained to highlight the ‘adult’ brain cells (green) and the ‘baby’ cells (red). This shows how the cells have self-organized into a three-dimensional structure that folds in a very similar way to the human brain6. It’s very clearly not a brain, but it is useful for research because has many cells found in the human brain, a similar structure, and it’s all human cells!
Why do we use them?
Brain organoids are extremely useful when trying to understand different brain disorders and identify potential treatments7. Genes affected in human disorders, like Timothy’s syndrome, do not always produce the same disorder when altered in animals. Organoids can be a great alternative way to study them7.
In one particular study, researchers wanted to find a treatment for Timothy’s syndrome, which results from a genetic mutation in calcium channels found in the heart and brain8. Researchers took stem cells from people with mutations that cause Timothy’s syndrome and grew them into organoids over 250 days (wow!)8. These organoids were then injected into rat brains, to give the organoids a more structured and realistic environment. And guess what? The researchers were able to identify a treatment that stops the body from producing the defective calcium channels8.
It gets even more exciting, if you can believe it. Researchers can also use organoids to model different cancers9. One group looking at colon cancer grew cancerous gut organoids and injected them into mice9. The tumours produced look very similar to those seen in human colorectal cancer. This study was able to show that caloric restriction reduced tumour size, which is something we know works in human colorectal cancer9! In this case, the organoid system is a great way to study how different drugs kill tumours, or how a person's immune system might affect the progression of their cancer.
Similar research is being done on lung organoids to explore COVID-19 treatments10.
Organoids…together?
But if we’re talking about the pièce de résistance, it’s got to be the research looking at growing organoids together. A major limitation of single organoids is that they don’t interact with other organs like they do inside the human body. For example, the brain organoid doesn’t have an immune system, isn’t connected to the gut, and doesn’t have blood vessels. These are all important interactions to study in disease. We know that the communication between the gut and brain plays a role in psychiatric, neurodevelopmental, and neurodegenerative diseases11,12,13.
We don’t have a gut-brain organoid yet, but, recent research has shown that it is possible to grow more complex and integrated organoids. Liver organoids have been grown to have blood vessels, which is a massive breakthrough for understanding the toxicology of drugs14. And organoids that cover the foregut and midgut (mouth to colon) have also been grown15! Even if we’re not fully there yet with a brain-gut connection, we will be soon16. This will help us understand many different brain disorders and hopefully speed up the process of finding treatments.
In other news, it’s May! And that means REWIRE is almost here!
Are you stuck in a self-sabotaging habit?
Do you fixate on a particular story about yourself that you wish you could change?
Are negative beliefs holding you back from reaching your fullest potential?
If any of this sounds familiar, don’t worry – it’s not you, it’s your brain.
Pre-order using the link below before May 9th, or find it in stores after that!
Until next week,
Nicole x
P.S. Leave a comment with topics you want covered in future newsletters!
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