Brno scientists grow ‘mini brains’ to study Alzheimer’s disease
Scientists from Brno’s Masaryk University have grown hundreds of ‘mini brains’ the size of apple seeds using stem cells from Alzheimer’s patients. The idea is to study the causes and development of Alzheimer’s right from the moment the brain starts to develop, rather than waiting until the disease has begun to manifest itself – which may already be too late.
Grown in Petri dishes and kept in incubators, these tiny brains, only about half a centimetre in size, may hold the key to discovering the long-sought-after cause of Alzheimer’s disease, which is responsible for 60 to 70 percent of cases of dementia and is the seventh leading cause of death in the United States.
Generally, the brains of patients with Alzheimer’s disease are only examined after the disease has already begun to manifest – but this is already much too late to find out the cause in most cases. So this group of researchers decided to create these mini brains from stem cells so they could study their development from the very beginning to see how and when the disease first appears.
They are focussing on familial early-onset Alzheimer’s, a rare but very insidious form of the disease affecting around 5-10% of all Alzheimer’s patients, explains Tereza Váňová from the research team.
“These patients have Alzheimer’s in their genome and symptoms will start to appear very early and in a very severe form. Even in people as young as 30 or 40.”
To their surprise, they noticed that the mini-brains with familial Alzheimer’s, in contrast with the healthy control group, developed differently from the very outset. The cells don’t renew themselves at a normal rate and so the brain ages prematurely.
“We weren’t expecting that the changes would be visible so early on. The first signs of the disease appear much earlier than we had previously thought. We can see that the neurons have aged prematurely and fewer new ones form, even in cells that are only a few months old.”
Under a microscope, you can observe clusters of red dots in the brain tissue of a person with Alzheimer’s. This is the protein amyloid beta that forms clumps in patients with Alzheimer's disease that then deposit outside neurons in dense formations known as amyloid plaques – the more of them, the more advanced the stage of the disease.
For a long time it was thought that these amyloid plaques were the cause of neurodegeneration in Alzheimer’s patients. However, removing them doesn’t improve the patient’s condition. The Brno scientists think that the plaques are probably not the cause, but rather simply another manifestation of the disease.
Dáša Bohačiaková from the team says that genetics is more likely to blame. But most cases of Alzheimer’s are not familial and have a later onset, developing after 65 years of age and so are termed sporadic Alzheimer's disease. It is likely that sporadic Alzheimer's disease can be avoided, or at the very least delayed, by regular physical, mental and social activity. Unfortunately, says Dáša Bohačiaková, this is not the case with the early-onset form.
“In contrast, the familial form of Alzheimer’s is a given and it is only a matter of time whether the sufferer develops it at 30, 40 or 50.”
But the scientists intend to keep studying different forms of Alzheimer’s in the hope of a breakthrough – and to see how the mini-brains respond to different kinds of medication.
