Brain cell transplants that could restore the deteriorated minds of Alzheimer’s patients are on the horizon, after scientists have created mature neurons from stem cells.
Little can currently be done to reverse the damage to the brain in patients with dementia or other neurodegenerative diseases, where families have to watch their loved ones disappear mentally and physically.
But US scientists at Northwestern University have proven that it is possible to turn stem cells into neurons, with a breakthrough they say could allow damaged or lost brain cells to be replaced and potentially restore cognition.
Neurons can also be transplanted into patients with spinal cord injuries to help restore nerve sensations.
Previous attempts to create neurons have stalled because the cells remain immature and unable to carry out complex signals or the branching and electrical activity normally seen in mature brain cells.
“Once you have a stem cell that you manage to turn into a neuron, it’s going to be a young neuron,” said Samuel Stupp, professor of Materials Science, Chemistry and Medicine at Northwestern University in Chicago.
“But you need a mature neuron for it to be therapeutically useful. It would be like asking a baby to do something that should otherwise be done in an adult human.
“Mature neurons are better able to establish synaptic connections that are essential for neuronal function.”
Doctors can turn skin cells into stem cells
To solve the problem, the researchers cultured immature neurons on a small network of rapidly acting synthetic signaling molecules—a process that mimics the conditions surrounding neurons as they evolve over time in the body.
The faster the molecules moved, the more mature the neurons.
This means that in the future, doctors could take skin cells from a patient and turn them into stem cells, and then use this technique to build a bank of healthy neurons for transplantation into the brain or spinal cord.
The cells are genetically matched to the patient so there is no chance of rejection.
The team believes it could provide a promising treatment for spinal cord injuries as well as neurodegenerative diseases such as Alzheimer’s disease, amyotrophic lateral sclerosis (ALS), Parkinson’s disease or multiple sclerosis.
There are approximately 950,000 dementia patients, 145,000 Parkinson’s patients, 130,000 multiple sclerosis patients and 5,000 ALS patients living in the UK. However, there is currently no way to improve or reverse conditions.
Discovery will allow scientists to study diseases in more detail
The invention will also allow scientists to study these diseases in greater detail because they can now grow very mature diseased brain cells in a dish and test new treatments and drugs.
As part of the research, the team took skin cells from a patient with ALS and transformed them into stem cells, then motor neurons, and aged them significantly until they began to show signs of the disease-causing protein buildup.
“For the first time, we have been able to see adult-onset neurological protein aggregation in stem cell-derived ALS patient motor neurons,” said Evangelos Kiskinis of Northwestern, lead author of the study.
“How picking triggers the disease is unclear. This is what we hope to learn for the first time.”
“Cell replacement therapy can be very challenging for a disease like ALS because motor neurons transplanted into the spinal cord need to project their long axons to appropriate muscle areas in the periphery, but it may be easier for Parkinson’s disease.
“Either way, this technology will be transformative.”
‘far beyond’ current capabilities
But experts in the UK warned that treatment using stem cells is a long way off and could face many challenges.
Commenting on the research, Alzheimer’s Research UK senior research fellow Prof.
“The brain is an extremely complex organ, and Alzheimer’s doesn’t just affect one type of nerve cell or one particular area of the brain.
“Each nerve cell in the brain may have thousands of connections with other cells. The total number of these connections reaches hundreds of trillions.
“While stem cell therapies for Alzheimer’s are promising, there are major challenges ahead with this approach. Even if we can promote the growth of new cells to directly replace those damaged by Alzheimer’s – new growing cells are also damaged unless we also address the disease processes.
“So, stem cell-based therapies have a long way to go before reaching people with diseases like Alzheimer’s.”
The research has been published in the journal Cell Stem Cell.