Autism spectrum disorder affects individuals in varying degrees, with some experiencing milder symptoms and others facing significant challenges in social, language, and cognitive skills. A recent study on mini-brains developed in the lab sheds light on the biological foundations that underpin this diversity in autism, offering valuable insights that could enhance our comprehension and management of this complex neurological condition.
Conducted by an international team of scientists, the research involved the use of induced pluripotent stem cells (iPSCs) extracted from the blood of 10 toddlers diagnosed with autism and 6 control individuals without the condition. These iPSCs were then cultivated into brain cortical organoids (BCOs), which serve as simplified 3D models of brain structures. Utilizing these organoids enables researchers to delve into the inner workings of the body without the need to utilize live organs, which are obviously off-limits for such studies.
One of the pivotal discoveries of the study was that the ‘mini-brains’ generated using iPSCs from autistic children exhibited a 40 percent increase in size compared to those from neurotypical controls. Moreover, the researchers noted that larger sizes and accelerated growth in the BCOs correlated with more severe forms of autism, offering critical insights into the early stages of autism development within the brain.
“We found that there is a direct relationship between the size of the embryonic BCO and the severity of the child’s later autism social symptoms,” stated neuroscientist Eric Courchesne. “Toddlers diagnosed with profound autism, the most severe form of autism, displayed the most substantial BCO overgrowth during embryonic development, whereas those with mild autism symptoms exhibited only minor overgrowth.”
The researchers also observed a correlation between overgrowth in the BCOs and overstimulation in specific regions of the brains of children with severe autism, resulting in reduced responsiveness to social stimuli. “Notably, toddlers with profound autism and enlarged BCOs demonstrated significantly enlarged primary auditory and somatosensory cortices,” the researchers noted in their published paper. This observation sheds light on sensory and social attention challenges often observed in individuals with autism.
In addition to the multifaceted factors that contribute to autism, the study suggests that some form of brain overstimulation may be involved, even at early embryonic stages. This newfound understanding contributes substantially to our perception of autism and its impact on approximately 1 percent of the population afflicted by the condition. By elucidating the embryonic origins of autism subtypes, particularly profound and mild autism, researchers can now identify and measure the biological underpinnings of social and brain development associated with the disorder.
As our comprehension of autism evolves and expands, studies like this bring us closer to uncovering how autism manifests and progresses. “During embryogenesis, the biological foundations of two subtypes of ASD social and brain development – profound autism and mild autism – already exist and are quantifiable,” emphasized the researchers.
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