Alzheimer’s and Dementia: Current Treatments and What the Future May Offer

What Is Alzheimer’s Disease?

Alzheimer’s is a brain disease that causes cognitive impairment (difficulty remembering things and thinking). It is a progressive disease that usually starts with mild symptoms and worsens over time. People can get Alzheimer’s disease at any age, but it is most common in people older than 65 years old.

What Causes Alzheimer’s?

Understanding how and why Alzheimer’s occurs may help scientists develop new treatments.

Protein Buildup in the Brain

Scientists think Alzheimer’s is caused by an abnormal buildup of certain proteins in the brain. Research has focused on two proteins — amyloid and tau.

The amyloid protein breaks down into a smaller protein called beta-amyloid. People with Alzheimer’s have too much beta-amyloid protein, causing it to clump together, forming beta-amyloid plaques that disrupt signaling between brain cells.

Tau is a protein that helps to stabilize the structure inside brain cells. In people with Alzheimer’s, the tau protein stops functioning as it should. It sticks to other tau proteins, forming a neurofibrillary tangle, also known as a tau tangle. These tangles get in the way of communication between brain cells.

Beta-amyloid plaques and neurofibrillary tangles are seen only in people with Alzheimer’s disease. There are current treatments available that target the formation of beta-amyloid plaques. Future treatments may also target neurofibrillary tangles.

Decreased Neuron Communication

Researchers have also noticed that some neurotransmitters (chemical messengers) are particularly low in people with Alzheimer’s — especially the neurotransmitter acetylcholine. Without acetylcholine, it is more difficult for neurons to communicate. Drugs that increase acetylcholine in the brain are used to improve symptoms.

Inflammation

The immune system of people with Alzheimer’s may not work properly. Immune cells in the brain — called glial cells — help to clear toxins and waste. The glial cells of people with Alzheimer’s don’t function as they should and don’t clean up this waste. The buildup of toxins and waste in the brain causes inflammation, which is harmful to the brain.

Reduced Blood Flow

Vascular problems (problems with blood flow) are common in people with Alzheimer's. Blood vessels in the brain can get blocked by beta-amyloid plaques, strokes, or atherosclerosis (hardening of the arteries). When this happens, it is harder for oxygen and nutrients to make it to all parts of the brain. Additionally, it is harder for the brain to clear away beta-amyloid plaques and neurofibrillary tangles through the blood.

Neuron Death

The damage caused by beta-amyloid plaques, tau tangles, inflammation, and vascular problems results in the death of brain cells. When brain cells die, the brain begins to shrink.

The first areas of the brain to start shrinking are usually the entorhinal cortex and hippocampus, which are tied to memory. As the disease progresses, the cerebral cortex is affected. This area of the brain is responsible for language, problem-solving, and behavior.

What Are the Symptoms of Alzheimer’s?

Changes in the brains of people with Alzheimer’s begin before symptoms do. The first symptom people usually notice is memory loss.

Other symptoms include problems with:

Who Gets Alzheimer’s Disease?

Doctors aren’t sure why some people develop Alzheimer’s disease and others don’t. It is likely a combination of several different factors that increase a person’s risk.

Factors that increase your risk of Alzheimer’s include:

What Treatments Are Currently Available?

There isn’t currently a cure for Alzheimer's. Treatments focus on slowing the progression of the disease and improving the symptoms of dementia.

Treatments that Slow the Progression of Alzheimer’s

Treatments that can slow the progression of Alzheimer’s — also known as disease-modifying treatments — are available for people in the early stages of Alzheimer’s. These medications are known as anti-amyloid antibodies. Antibodies are proteins that recognize and hold onto specific substances or proteins so immune cells can remove them.

Anti-amyloid antibodies recognize the beta-amyloid plaques in the brain and recruit the immune system to clear up these plaques.

Two treatments are approved by the US Food and Drug Administration (FDA) to treat mild cognitive impairment due to Alzheimer’s disease:

These medications are usually given at your doctor’s office or clinic because they are given intravenously (by an injection in the vein). You must return once or twice a month to get your next dose.

The most common side effects of these medications are headaches, infusion-related reactions, and falls. They can also cause brain swelling, known as an amyloid-related imaging abnormality (ARIA). Although ARIAs don’t typically cause symptoms, they can be serious.

Medications That Treat Dementia Symptoms

There are two main classes of medications that can help with the cognitive symptoms of Alzheimer’s and dementia. These medications do not treat the underlying cause of dementia.

Cholinesterase Inhibitors

Cholinesterase inhibitors are used in people with mild to moderate Alzheimer’s. These drugs improve communication between neurons by increasing the amount of acetylcholine available.

Cholinesterase Inhibitors approved by the FDA include:

These medications are taken by mouth once or twice daily, depending on the medication. Donepezil and rivastigmine are also available as a patch that is applied to the skin.

The side effects of these medications usually get better after the first two weeks of taking them. The most common side effects of cholinesterase inhibitors are:

Glutamate Regulators

Glutamate regulators can be used by people with moderate to severe dementia due to Alzheimer’s. Memantine (Namenda) is the only medication in this class. It works by protecting nerve cells from excess glutamate, which can build up due to the damage caused by Alzheimer’s.

Memantine is commonly used along with a cholinesterase inhibitor. A combination of memantine and donepezil is available under the brand name Namzaric.

The most common side effects of memantine are:

Treatments That Don’t Involve Medication

Although medication is an important part of Alzheimer’s treatment, it is not the only factor involved in care. There are several methods for improving symptoms and increasing the quality of life of a person living with Alzheimer’s, such as:

What Future Treatments Could Be Coming for Alzheimer’s?

Alzheimer’s disease is not fully understood, making it difficult to develop new treatments for it. Furthermore, developing a new drug is a lengthy process. More than 200 research projects studying Alzheimer’s treatments have been abandoned in the past ten years.

Research into future treatment for Alzheimer’s disease is focused on medications that can stop, slow, or reverse the course of the disease. As of January 2023, clinicaltrials.gov lists more than 150 clinical trials that are recruiting patients for Alzheimer’s studies.

As scientists learn more about how and why Alzheimer’s occurs, they are discovering new targets for future therapies. Some of the possible treatments are discussed below.

Activating the Immune System

The two currently available disease-modifying treatments — aducanumab and lecanemab — are anti-amyloid antibodies that enlist the help of the body’s own immune system.

Researchers are also exploring the possibility of using this method against tau tangles.

Scientists have also been researching an Alzheimer’s vaccine that can activate the immune system to attack amyloid plaques and tau tangles similar to how it attacks bacteria and viruses.

Preventing Damage

Researchers have been investigating a protein called Fyn kinase that affects how well synapses work. In Alzheimer’s, Fyn kinase levels are increased, causing damage to the synapses.

A drug, called saracatinib, that was originally developed as a cancer therapy is now being studied in Alzheimer’s patients. This drug blocks Fyn kinase, which may decrease the damage it causes. It has shown promising results in reversing memory loss in mice and is currently in human clinical trials.

Preventing the Formation of Beta-Amyloid Plaques

If the formation of beta-amyloid plaques can be stopped or slowed, it might have a positive effect on the course of Alzheimer’s. However, these drugs have not proved to be beneficial in clinical trials and also have significant side effects.

Preventing Neurofibrillary Tangles

The tau protein is involved in forming neurofibrillary tangles. Scientists are working on developing drugs that can block tau from forming these tangles.

Reducing Inflammation

Inflammation is thought to be a key component of Alzheimer’s. Drugs that reduce inflammation may also benefit people with Alzheimer’s. Anti-inflammatories currently under investigation for use in Alzheimer’s include:

Balancing Hormones

Early clinical trials found that estrogen therapy in women after menopause may provide some protection against developing Alzheimer’s. However, other studies have not shown any benefit. Scientists will continue to study the effect of hormones on Alzheimer’s.

Stem Cell Therapy

Stem cell therapy may be able to help repair brain cells damaged by Alzheimer’s disease. Stem cells are human cells that can develop into any kind of cell in the body. This type of therapy involves implanting stem cells into the brain of a person with Alzheimer’s.

Stem cell therapy has shown promise in mice, but human trials have not yet started.

Repurposing Drugs Used To Treat Other Conditions

Some medications that are currently used to treat other diseases may prove to be beneficial in the treatment of Alzheimer’s.

Insulin

Insulin is a hormone that helps regulate blood sugar. Insulin regulation in the brain could be affected by Alzheimer’s disease. Researchers have been investigating if using an insulin nasal spray might improve the symptoms of Alzheimer’s. Study results have been mixed with some showing a benefit and others showing none.

Drugs That Prevent Cell Death

Researchers are currently investigating drugs that may prevent cell death in the brain. Two drugs currently in use for other conditions may be helpful in Alzheimer’s.

Levetiracetam is used to treat seizures. A low dose of this medication may help protect the brain from damage.

Icosapent ethyl is a purified omega-3 fatty acid used to lower cholesterol. It has shown promise in protecting neurons from damage.

Drugs That Reduce Inflammation

Scientists know that Alzheimer’s disease involves inflammation. They are exploring whether anti-inflammatory drugs used in autoimmune disorders (such as rheumatoid arthritis and lupus) might be helpful in treating Alzheimer’s.

Drugs That Improve Blood Flow

Improving blood flow to the brain is important to deliver oxygen and clear away toxins. Researchers are investigating whether drugs already being used to lower blood pressure and decrease cholesterol can reduce the risk of Alzheimer’s and help the symptoms and slow its progress.

Can Alzheimer’s or Dementia Be Prevented?

There are no proven treatments or methods to reduce your risk of developing Alzheimer’s. Some risk factors — like your age and family history — can’t be changed, but you can take steps to reduce your risk of Alzheimer’s.