Imagine being able to grow organs from your very own tissue. In labs around the world scientists are doing such by creating miniature, three-dimensional cultures that replicate much of the structural complexity of an organ in vivo. These structures known as organoids are forever revolutionising the future of medicine and biological studies. 

Organoids can be grown from several cell sources including embryonic, induced 

pluripotent and even cancer cells. To begin, cells from existing organoids or organs are taken and placed in a nutrient-rich medium on low attachment plates. Over several days, these cells will cluster to form three-dimensional structures called spheroids. The spheroids will then be embedded in a gel-like substance which takes the role of a natural support structure. The culture is kept warm and supplied with varying growth factors depending on the organ being modeled - for example EGF for epithelial and tumor organoids or FGF10 for stomach and liver tissue. Over the next few weeks the organoids grow and mature, becoming functional versions of their intended organ. They can then either be maintained or frozen for future use. 

These tiny creations may be small (ranging for the size of a from less than the width of a hair to five millimeters) but what they can do is extraordinary. Organoids are changing the way we understand the development of disease. Since they mimic the structure of organs in vivo, researchers are able to see how certain illnesses progress on a cellular level in ways that were never possible before. Notably, brain organoids have become useful in studying neurodegenerative conditions such as Alzheimer’s and Parkinson’s as researchers have been able to study how certain proteins misfold and spread through brain organoids. 

Organoids also have applications in drug testing and the development of personalised medicine. Traditionally, many drugs show variation when tested against both humans and animals. A study at AstraZeneca showed a neurological drug performing poorly at the experimental stage on both rat and dog brain organoids. Yet, when tested on human brain organoids, it responded effectively helping researchers realise the limitations of animal testing while highlighting the future of organoids in drug testing. In a tragic case, a 2016 French drug trial left one participant brain dead and five others seriously ill after a neurological drug accumulated in the brain instead of safely being filtered out. Leading organoid scientist, Dr. Madeline Lancaster notes that the use of brain organoids could have predicted such an outcome in earlier clinical stages showing how crucial these models can be in drug trials. Alongside this, organoids are also being used in drug safety and toxicity. Since organoids are derived from patient specific stem cells, they in turn are also patient specific. This allows scientists to explore how different people might respond to the same treatment, offering a breakthrough in safer and more effective approaches to personalised medicine.  

In the near future, it is possible that organoids may play a key role in regenerative medicine, helping repair and replace damaged tissues. Researchers are currently experimenting with transplanting, such as intestinal organoids and liver buds into animals replacing damaged tissue. This is a technique that shows early promise for human therapy. In the long-term, patient specific organoids could be used to create personalised grafts or organ replacements, reducing the risks associated with donor organs. 

However, organoid advancements are not without limitations. They are often simplified and lack advanced systems such as blood vessels or immune systems. Recreating the human body’s structure will forever remain a challenge with ethical questions beginning to arise when working with brain and embryo-like organoids. Despite these limitations, their potential is endless bringing science and human-centred healthcare closer.   

Organoids truly mark a remarkable step forward in the approach to medicine. These miniature structures allow researchers to bridge the gap between clinical research and real physiology by providing an accurate model. As technology improves, there will likely be many ways that they impact medicine, most of which remain to be discovered. Although challenges persist, organoids undoubtedly represent a crucial step toward a more grounded understanding of human biology.

References

1. Javier B. (2017) "Organoids : A new window into Disease, Development and Discovery,” Harvard Stem Institute. Available at https://www.hsci.harvard.edu/organoids

2.  Debomita C. PhD (2024) “An Introduction to Organoids, Organoid Creation, Culture and Applications,” Technology Networks. Available at https://www.technologynetworks.com/cell-science/articles/an-introduction-to-organoids-organoid-creation-culture-and-applications-369090

3. Madeline L. (2024) “Creating brain organoids to uncover what makes us human,” Cambridge Society for the Application of Research. Available at https://www.youtube.com/watch?v=x1Pg56WWm5U&t=2207s

4. Qinying W., Fanying G., Yanlei M. (2022) “Applications of human organoids in the personalized treatment for digestive diseases,” Nature. Available at https://www.nature.com/articles/s41392-022-01194-6#Abs1

5. Ruth Lehmann, Connie M Lee b, Erika C Shugart c, Marta Benedetti d, R Alta Charo e, Zev Gartner f, Brigid Hogan g, Jürgen Knoblich h, Celeste M Nelson i, Kevin M Wilson. (2019) “Human organoids: a new dimension in cell biology,” PubMed Central. Available at ​​https://pmc.ncbi.nlm.nih.gov/articles/PMC6724519/
   

6. Helen Shen, (2018) “Organoids have opened avenues into investigating numerous diseases. But how well do they mimic the real thing?” PNAS. Available at https://www.pnas.org/doi/10.1073/pnas.1803647115