No stem cell treatments are currently approved for AD. AD affects many different types of neurons in many parts of the brain. This poses a complex problem for repairing the brain. Below are some ways researchers are using stem cells to help with AD:

Understanding the disease

Scientists are using stem cell technology to grow neurons in the lab to study AD. Researchers use these lab-grown neurons created from the cells of AD patients to study any abnormalities that might promote the progression of Alzheimer’s disease. This includes studying differences in how these neurons produce, move and release the amyloid beta protein, which forms plaques, and tau protein, which forms the tangles in patients’ brains. Another area that researchers are examining is the role of the immune system in AD. Recent studies of the genes of AD patients suggest that a hyperactive immune system could lead to brain inflammation and damage to neurons. Researchers recently have been able to use stem cells from AD patients to grow microglia, the brain’s immune cells. Researchers want to know how these cells interact with amyloid beta and if these cells might trigger the start of AD in people.

Developing New Drugs

Growing neurons from stem cells in the lab provides an important tool for researchers to look for new drugs that can reduce amyloid and tau, and also find disease signposts that can help diagnose patients with AD earlier.

Replacing Lost Cells

Although research shows that neural stem cells can form new neurons, transplanting these into the brain of an Alzheimer’s patient to make new, healthy neurons is not straightforward. Putting new cells into a brain with AD won’t fix why neurons are dying. They might only offer temporary help before more neurons are lost. While early studies using neural stem cell transplants given to mice with a disease similar to AD have shown some positive results, researchers are still studying what these stem cells are doing and how they might help repair the brain. There are many questions to answer before cell therapies should be tried on human patients.

There are many different neurons throughout the brain that are destroyed by AD, making each case unique and very difficult to treat.

Successful stem cell treatments will need to distribute cells to damaged areas throughout the brain, make the correct types of neurons and other brain cells, correctly ‘wire’ new neurons into existing neuron networks, and, above all, be safe (e.g. not cause cancer or other complications).

Some researchers argue that using new neurons made with stem cells to study Alzheimer’s disease will not accurately represent aged brain cells. Other researchers think this approach could be the best way to understand the earliest stages of AD.

If stem cell treatments are eventually developed for AD, these treatments do not stop the cause of AD, meaning treatments may not last and people could experience relapses.