Alzheimer’s disease, named for the German pathologist Dr. Alois Alzheimer, is a progressive brain disorder that affects a person’s memory and ability to carry out daily tasks. The number of Americans living with Alzheimer’s disease is projected to grow from 6.9 million in 2020 to nearly 14 million people by 2060, according to the Centers for Disease Control and Prevention.
While there is currently no cure for Alzheimer’s disease, scientific developments over the last several years have allowed healthcare professionals at UTHealth Houston and beyond to focus on prevention and slowing the progression of the condition.
Dementia is an umbrella term for any cause of memory loss as a person ages. Alzheimer’s disease is the most common cause of dementia, but not the only cause. Alzheimer’s is caused by certain proteins, called amyloids, accumulating in the brain to form plaques. Other causes of dementia include depression, sleep apnea, and stroke.
Alzheimer’s disease develops long before a patient has dementia. The earliest symptoms of Alzheimer’s might be nothing more than a vague feeling by the patient that their thinking is not up to par.
The first clear signs revealed are called amnestic mild cognitive impairment, where the patient has a hard time making new memories. Friends and family might notice the patient repeats questions or forgets minor events from the previous day. Formal tests will show the patient cannot memorize a list of words or a story as well as normal.
There are now blood tests for Alzheimer’s disease that are reliable enough to be used in primary care. Ptau-217, a protein released by the brain of Alzheimer’s patients, can be detected in the blood. It’s recommended that patients over 65 with memory concerns ask their doctor for this test. One of two brief cognitive exams, the Mini-Mental Status Exam or Montreal Cognitive Assessment, is suggested as an objective measure of the patient’s memory. Finally, an MRI of the brain is needed to rule out strokes, tumors, or other visible pathology in the brain.
Alzheimer’s disease cannot be cured, but science has evolved to the point that, for the first time, healthcare professionals can seriously improve its progression.
Patients with Alzheimer’s can get an amyloid PET scan, a type of brain imaging that shows the amyloid plaques, to confirm the diagnosis. There are two FDA-approved drugs to remove the amyloid: Leqembi and Kisunla. Both drugs are anti-amyloid antibodies. Just like the immune system uses antibodies to fight infection, these drugs use manufactured antibodies to target the amyloid plaques. The drug binds to the amyloid proteins, and the patient’s own immune system removes the plaques from the brain.
If Alzheimer’s is caught while a patient only has mild cognitive impairment, Leqembi and Kisunla can add roughly three good years to a patient’s lifespan. While that is not a cure, it is far more than what healthcare professionals could do before.
Now that these drugs are FDA-approved for mild cognitive impairment, they are being tested in patients older than 65 who have amyloid plaques but no symptoms of memory loss. If those trials are positive, it will mean Alzheimer’s onset could be delayed. Ideally, everyone would be screened for Alzheimer’s at a certain age, similar to how patients are screened for colon cancer or osteoporosis.
For the last century, dementia care in the U.S. has been built around careful research. Traditionally, dementia specialists spent many hours annually with each patient for years as the patients slowly declined. This led to neurologists who provided a high level of care to each patient, but saw very few patients at a time. An estimated 100,000 patients in the greater Houston area likely qualify for anti-amyloid therapy, but only 1,000 have received it thus far.
Reference:
1. David Hunter, MD, Associate professor, UTHealth Houston, https://med.uth.edu/neurology/2022/10/31/david-h-hunter-md/
2. https://www.cdc.gov/alzheimers-dementia/about/alzheimers.html
(Newswise/MF)