Recently, neuroscientist Alysson R Muotri and his team from the University of California, San Diego, developed clusters of nerve cells. Called mini-brains, these were pinned into an insect-sized robot in order to study their neural activity. Interestingly, the researchers found the brain organoids were replicating the signals of brain waves.

This was the first time in history that a lab-grown mini-brain organ is replicating the complex patterns of neural activity which is almost similar to a premature baby. In a blog post, the researchers noted, “We never had a brain organoid that can function like the human brain,” He added, “The electrical activity of these brain organoids are emitting something we see during normal human development. So, it’s a strong indication that what we have should work and function like the human brain.”

Growing artificial organs is not a new thing in science. Researchers from around the globe are working to enhance organoid systems as well as apply them to a number of causes. Regenerative medicine research is helping the researchers to investigate and mitigate various types of chronic diseases.

Mini Brains

An organoid or a mini-brain is a cell-culture technology which is a three-dimensional tissue structure assembled from organ-specific stem cells. This technology is used to study and understand the human-specific physiology. 

The mini-brain developed by these researchers used human stem cells to form a complex tissue from the cortex which is a brain region that controls cognition and interprets sensory information. The researchers were involved in this development for several months where they had been working to culture hundreds of brain organoids. 

The organoids displayed irregular EEG patterns which resembled synchronised electrical activity that is usually seen in developing brains. When the researchers compared these rhythms to the EEGs of premature babies, they found that the organoids’ patterns mimicked those of infants born at 25–39 weeks post-conception. According to researchers, the organoids aren’t close to being real human brains as they don’t contain all the cell types found in the cortex, and they don’t connect to other brain regions. 

Implementing Machine Learning Algorithm

The researchers developed a machine-learning algorithm by using a publicly available dataset of 567 EEG recordings from 39 babies born prematurely, between 24 and 38 weeks gestation, and for several weeks after birth. This algorithm is then used to compare the discovered brain organoid electrical patterns to the available dataset in order to predict the age of the signals emitted by the organoids. The algorithm revealed that the electrical impulse pattern of the organoids is almost similar to the features of a premature infant.

Applications 

This technology has opened up a number of possibilities for scientific discovery in developmental biology as well as translational research. It will help researchers to study the early development of brain cells. Human-specific disease mechanisms can be said as one of the potential applications of organoid models. It facilitates the analysis of molecular mechanisms behind the disease of human body.

The organoid structures can also be utilised in a number of use cases such as examination of organ development, mode diseases, test sensitivity and toxicity of drugs and formation complex tissues for transplantation, among others. The organoids systems are currently being used for modelling cancer development and treatments and the cancer-based organoids were utilised in a successful array for drug sensitivity testing.  

Limitations Of Lab-Grown Organs

There are certain limitations of lab-grown organs such as:

• These organs do not grow with the person who has implanted it
• They don’t have the ability to repair themselves
• They are incapable to secrete signalling agents

Currently, there is little or no opinion about how the cells do when they assemble into organoids.

Outlook

This research has opened up a door for the researchers to produce semi-conscious life artificially. Over the years, there has been an increased number of people waiting for organ donors in India. According to reports, 2 lakh people await kidney transplants each year but only 10,000 or 5% get it. In 2017, 50,000 individuals waited for a heart transplant and only 339 deceased heart donations were witnessed. The establishment of the organoid system will provide a milestone on the path toward the existing shortcomings.