Cell therapy beneficial for Alzheimer's patients

Transplanting a special type of neuron into the brain may restore cognitive functions in patients diagnosed with Alzheimer’s, a study has found. Like a great orchestra, your brain relies on the perfect coordination of many elements to function properly. And if one of those elements is out of sync, it affects the entire ensemble. In Alzheimer’s disease, for instance, damage to specific neurons can alter brainwave rhythms and cause a loss of cognitive functions.

One type of neuron, called inhibitory interneuron, is particularly important for managing brain rhythms, said researchers at Gladstone Institutes in the US.

In the study, published in the journal Neuron, the scientists uncovered the therapeutic benefits of genetically improving these interneurons and transplanting them into the brain of a mouse model of Alzheimer’s disease.

Interneurons control complex networks between neurons, allowing them to send signals to one another in a harmonised

way. You can think of inhibitory interneurons as orchestra conductors.

They create rhythms in the brain to instruct the players — excitatory neurons — when to play and when to stop. An imbalance between these two types of neurons creates disharmony and is seen in multiple neurological and psychiatric disorders, including Alzheimer’s disease, epilepsy, schizophrenia, and autism.

“We took advantage of the fact that transplanted interneurons can integrate remarkably well into new brain tissues, and that each interneuron can control thousands of excitatory neurons,” said Jorge Palop from Gladstone Institute.

“These properties make interneurons a promising therapeutic target for cognitive disorders associated with brain rhythm abnormalities and epileptic activity,” Palop said.

First, the scientists had to overcome a significant challenge. When they transplanted regular interneurons, they saw no beneficial effects, presumably because Alzheimer's disease creates a toxic environment in the brain.

The researchers then genetically boosted the activity of inhibitory interneurons by adding a protein called Nav1.1. They discovered that the interneurons with enhanced function were able to overcome the toxic disease environment and restore brain function.