Already-existing clinical laboratory blood test may be new standard for detecting Alzheimer’s biomarkers
In Sweden, an independent study of an existing blood test for Alzheimer’s disease—called ALZpath—determined that this diagnostic assay appears to be “just as good as, if not surpass, lumbar punctures and expensive brain scans at detecting signs of Alzheimer’s in the brain,” according to a report published by The Guardian.
Alzheimer’s disease is one of the worst forms of dementia and it affects more than six million people annually according to the Alzheimer’s Association. Clinical laboratory testing to diagnose the illness traditionally involves painful, invasive spinal taps and brain scans. For that reason, researchers from the University of Gothenburg in Sweden wanted to evaluate the performance of the ALZpath test when compared to these other diagnostic procedures.
Motivated to seek a less costly, less painful, Alzheimer’s biomarker for clinical laboratory testing, neuroscientist Nicholas Ashton, PhD, Assistant Professor of Neurochemistry at the University of Gothenburg, led a team of scientists that looked at other common biomarkers used to identify changes in the brain of Alzheimer’s patients. That led them to tau protein-based blood tests and specifically to the ALZpath blood test for Alzheimer’s disease developed by ALZpath, Inc., of Carlsbad, Calif.
In their JAMA article, they wrote, “the pTau217 immunoassay showed similar accuracies to cerebrospinal fluid biomarkers in identifying abnormal amyloid β (Aβ) and tau pathologies.”
In an earlier article published in medRxiv, Ashton et al wrote, “Phosphorylated tau (pTau) is a specific blood biomarker for Alzheimer’s disease (AD) pathology, with pTau217 considered to have the most utility. However, availability of pTau217 tests for research and clinical use has been limited.”
Thus, the discovery of an existing pTau217 assay (ALZpath) that is accessible and affordable is a boon to Alzheimer’s patients and to the doctors who treat them.
“The ALZpath pTau217 assay showed high diagnostic accuracy in identifying elevated amyloid (AUC, 0.92-0.96; 95%CI 0.89-0.99) and tau (AUC, 0.93-0.97; 95%CI 0.84-0.99) in the brain across all cohorts. These accuracies were significantly higher than other plasma biomarker combinations and equivalent to CSF [cerebrospinal fluid] biomarkers,” an ALZpath press release noted.
“This is an instrumental finding in blood-based biomarkers for Alzheimer’s, paving the way for the clinical use of the ALZpath pTau217 assay,” stated Henrik Zetterberg, MD, PhD (above), Professor of Neurochemistry at the University of Gothenburg and co-author of the study. “This robust assay is already used in multiple labs around the globe.” Clinical laboratories may soon be receiving doctors’ orders for pTau217 blood tests for Alzheimer’s patients. (Photo copyright: University of Gothenburg.)
Study Details
Ashton’s team conducted a cohort study that “examined data from three single-center observational cohorts.” The cohorts included:
“Participants included individuals with and without cognitive impairment grouped by amyloid and tau (AT) status using PET or CSF biomarkers. Data were analyzed from February to June 2023,” the researchers wrote.
These trials from the US, Canada, and Spain featured 786 participants and featured “either a lumbar puncture or an amyloid PET scan to identify signs of amyloid and tau proteins—hallmarks of Alzheimer’s disease,” The Guardian reported, adding that results of the University of Gothenburg’s study showed that the ALZpath pTau217 blood test “was superior to brain atrophy assessments, in identifying signs of Alzheimer’s.”
“80% of individuals could be definitively diagnosed on a blood test without any other investigation,” Ashton told The Guardian.
Diagnosis Needed to Receive Alzheimer’s Disease Treatments
“If you’re going to receive [the new drugs], you need to prove that you have amyloid in the brain,” Ashton told The Guardian. “It’s just impossible to do spinal taps and brain scans on everyone that would need it worldwide. So, this is where the blood test [has] a huge potential.”
Even countries where such drugs were not yet available (like the UK) would benefit, Ashton said, because the test, “Could potentially say that this is not Alzheimer’s disease and it could be another type of dementia, which would help to direct the patient’s management and treatment routine.”
However, Ashton himself noted the limitations of the new findings—specifically that there is no success shown yet in Alzheimer’s drugs being taken by symptom-free individuals.
“If you do have amyloid in the brain at 50 years of age, the blood test will be positive,” he said. “But what we recommend, and what the guidelines recommend with these blood tests, is that these are to help clinicians—so someone must have had some objective concern that they have Alzheimer’s disease, or [that] their memory is declining,” he told The Guardian.
Experts on the Study Findings
“Blood tests could be used to screen everyone over 50-years old every few years, in much the same way as they are now screened for high cholesterol,” David Curtis, MD, PhD, Honorary Professor in the Genetics, Evolution and Environment department at University College London, told The Guardian.
“Results from these tests could be clear enough to not require further follow-up investigations for some people living with Alzheimer’s disease, which could speed up the diagnosis pathway significantly in future,” Richard Oakley, PhD, Associate Director of Research and Innovation at the Alzheimer’s Society, UK, told The Guardian.
Though Oakley found the findings promising, he pointed out what should come next. “We still need to see more research across different communities to understand how effective these blood tests are across everyone who lives with Alzheimer’s disease,” he said.
“Expanding access to this highly accurate Alzheimer’s disease biomarker is crucial for wider evaluation and implementation of AD blood tests,” the researchers wrote in JAMA Neurology.
“ALZpath makers are in discussions with labs in the UK to launch it for clinical use this year, and one of the co-authors, Henrik Zetterberg, MD, PhD, Professor of Neurochemistry at the University of Gothenburg, is making the assay available for research use as part of the ‘biomarker factory’ at UCL,” The Guardian reported.
In the US, to be prescribed any of the available Alzheimer’s medications, a doctor must diagnose that the patient has amyloid in the brain. A pTau217 diagnostic blood test could be used to make such a diagnosis. Currently, however, the test is only available “for research studies through select partner labs,” Time reported.
“But later this month, doctors in the US will be able to order the test for use with patients. (Some laboratory-developed tests performed by certain certified labs don’t require clearance from the US Food and Drug Administration.),” Time added.
It may be that the University of Gothenburg study will encourage Alzheimer’s doctors in the UK and around the world to consider ordering pTau217 diagnostic blood tests from clinical laboratories, rather than prescribing spinal taps and brains scans for their Alzheimer’s patients.
Study findings may lead to new clinical laboratory tests, as well as vaccines and immunotherapies for neurodegenerative diseases
Research into the human genome continues to produce useful new insights. This time, a study led by researchers at Stanford University identified a genetic variation that is believed to help “slow or even stall” progression of neurodegenerative diseases, including Alzheimer’s and Parkinson’s, according to a press release. Because these genetic variations are common, it is likely that diagnostic tests can be developed for use by clinical laboratories.
Researchers at Stanford Medicine led the study which discovered that approximately one in five individuals carry the gene variant, a protective allele identified as DR4 (aka, HLA-DR4). It’s one of a large number of alleles found in a gene known as DRB1.
DRB1 is part of a family of genes collectively known as the human lymphocyte antigen complex or HLA. The HLA-DRB1 gene plays a crucial role in the ability of the immune system to see a cell’s inner contents.
“In an earlier study, we’d found that carrying the DR4 allele seemed to protect against Parkinson’s disease,” said Emmanuel Mignot, MD, PhD (above), Director of the Stanford Center for Narcolepsy, in a Stanford press release. “Now, we’ve found a similar impact of DR4 on Alzheimer’s disease.” Clinical laboratories may soon have new vaccines for both neurodegenerative diseases. (Photo copyright: Stanford University.)
DR4 Found to Impact Both Parkinson’s and Alzheimer’s Diseases
To perform their research, the team examined a large collection of medical and genetic databases from 176,000 people who had either Alzheimer’s or Parkinson’s disease. The people involved in the study were from numerous countries located in East Asia, Europe, the Middle East and South America. Their genomes were then compared with people who did not have the diseases, focusing on the incidence and age of onset.
“In an earlier study we’d found that carrying the DR4 allele seemed to protect against Parkinson’s disease,” said Mignot in the Stanford press release. “Now, we’ve found a similar impact of DR4 on Alzheimer’s disease.”
The team found that about 20% to 30% of people carry DR4, and that they have around a 10% risk reduction for developing the two diseases.
“That this protective factor for Parkinson’s wound up having the same protective effect with respect to Alzheimer’s floored me,” said Emmanuel Mignot, MD, PhD, the Craig Reynolds Professor of Sleep Medicine in the Department of Psychiatry and Behavioral Sciences at Stanford University and the Director of the Stanford Center for Narcolepsy, in the Stanford Medicine press release. “The night after we found that out, I couldn’t sleep.”
The scientists also analyzed data from autopsied brains of more than 7,000 Alzheimer’s patients and discovered that individuals who carry DR4 had fewer neurofibrillary tangles and that those tangles are composed mainly of modified tau proteins, a common biomarker for Alzheimer’s.
The presence of these tangles corresponds with the severity of Alzheimer’s disease. They are not typically seen in Parkinson’s patients, but the Stanford team found that Parkinson’s patients who did carry DR4 experienced later onset of symptoms.
Mignot stated that tau, which is essential in Alzheimer’s, may also play a role in Parkinson’s, but that further research is required to prove its function.
Both diseases are characterized by the progressive loss of certain nerve cells or neurons in the brain and are linked to an accumulation of abnormal proteins. The Stanford researchers suggested that the DR4 gene variant may help protect individuals from Alzheimer’s and Parkinson’s by preventing the buildup of tau proteins.
“This is a very interesting study, providing additional evidence of the involvement of the immune system in the pathogenesis of Alzheimer’s and Parkinson’s,” neurologist Wassim Elyaman, PhD, Assistant Professor of Neurological Sciences in Neurology, the Taub Institute and the Institute for Genomic Medicine at Columbia University, told Live Science.
New Vaccines and Immunotherapies
According to the Alzheimer’s Association, more than six million Americans are currently living with Alzheimer’s disease and approximately one in three Americans die with Alzheimer’s or another dementia.
The Parkinson’s Foundation states that nearly one million Americans are currently living with Parkinson’s disease, and that number is expected to rise to 1.2 million by 2030. Parkinson’s is the second-most common neurodegenerative disease after Alzheimer’s disease.
Even though the genetic analysis of the Stanford research is strong, more immune cell and blood-based research is needed to definitively establish how tau is connected to the two diseases.
This research could have implications for clinical laboratories by giving them biomarkers for a useful new diagnostic test, particularly for diagnosing Alzheimer’s and Parkinson’s.
Further, Mignot suggested that an effective vaccine could delay the onset or slow the progression of both diseases. He hopes to test his hypothesis on genetically modified mice and eventually human subjects.
New scientific insights from these studies represent progress in the effort to develop a clinical laboratory test that would enable physicians to diagnose Alzheimer’s Disease earlier and with greater accuracy
Most medical laboratory professionals are aware that, for more than 30 years, in vitro diagnostic (IVD) developers and pharmaceutical researchers have sought the Holy Grail of clinical laboratory testing—an accurate test for Alzheimer’s disease that is minimally-invasive and produces information that is actionable by clinicians at a reasonable cost. Such a test could spark a revolution in the diagnosis and treatment of this debilitating disease and would improve the lives of tens of thousands of people each year.
Now, two different research studies being conducted in Germany and Japan may have developed such tests that use blood samples. The tests detect specific biomarkers found in Alzheimer’s patients and one day could enable physicians to diagnose the disease in its preclinical stages.
A healthy brain has amyloid-beta plaques, too. However, in a person with Alzheimer’s disease, the amyloid-beta is misfolded, formed like a sheet, and toxic to nerve cells, the researchers explained in a press release.
The test works with small amounts of blood plasma and employs an immuno-infrared-sensor, also developed at Ruhr University. The sensor measures the amounts of both pathological (the misfolded kind) and healthy amyloid-beta in the blood.
Amyloid plaques can start to form decades prior to the onset of Alzheimer’s symptoms, making them identifiable biomarkers that can be used as a “preselection funnel in two‐step diagnostics,” the researchers noted.
“The use of the immuno‐infrared‐sensor as an initial screening funnel to identify people who should undergo further diagnostics and eventually take part in clinical trials on therapeutics targeting Aβ misfolding might already be an important step forward because subjects with early AD stages are hard to identify,” the researchers note. “To our knowledge, there is today no other plasma test available, which has been tested both in an AD research cohort and in the general population.”
Klaus Gerwert, PhD, (left)Chair of Biophysics at Ruhr University in Bochum, Germany, and Dr. Katsuhiko Yanagisawa, PhD, (right) molecular biologist and Director of the Center for Development of Advanced Medicine for Dementia in Obu City, Japan, both lead research teams that developed tests for identifying amyloid-β biomarkers in early onset Alzheimer’s patients. More research must be conducted before these assays could be offered by clinical laboratories. (Photo copyrights: International Max Planck Research School in Chemical and Molecular Biology/Nagoya University School of Medicine.)
Another Blood Test Finds Amyloid-Beta
Interestingly, just a few months ahead of the German researchers’ paper, scientists at the Center for Development of Advanced Medicine for Dementia (CAMD) in Obu City, Japan, published their own paper on a similar blood test they developed that also identifies high levels of amyloid-beta in patients with Alzheimer’s.
The study, which was published in Nature, involved 373 people: 121 Japanese in the discovery cohort set and 252 Australians in the validation data set. The test found amyloid-beta levels in the brain with 90% accuracy, The Scientist reported.
“These results demonstrate the potential clinical utility of plasma biomarkers in predicting brain amyloid-β burden at an individual level. These plasma biomarkers also have cost-benefit and scalability advantages over current techniques, potentially enabling broader clinical access and efficient population screening,” the researchers wrote in their paper.
Nevertheless, as of 2018, Alzheimer’s disease has impacted the lives of approximately 5.7 million Americans of all ages, according to the Alzheimer’s Association. And yet, doctors currently only have expensive positron emission tomography (PET) brain scans and invasive cerebrospinal fluid (CSF) analysis to identify the disease, generally in the latter stages of its development.
Thus, a less invasive, inexpensive test that accurately identifies biomarkers found in the majority of people during the early stages of the disease would be a boon to physicians who treat chronic neurodegenerative disease, medical laboratories that perform the tests, and, of course, the thousands of people each year who are diagnosed and suffer with this debilitating condition.
Low interest and a lack of diversity among study participants hinders research into one of America’s most fatal and costly chronic diseases
Finding enough people to participate in clinical laboratory trials for Alzheimer’s disease can be a daunting task for researchers. The shortage of participants has compelled scientists to develop innovative ways to locate volunteers for their studies. That includes “Swab-a-Palooza” events to make it easy for individuals to provide samples for this research and get speedy feedback about their ApoE.
Some researchers are hunting online and offering free genetic testing to interested individuals to ensure they obtain the number of participants needed for their trials. Both the Alzheimer’s Prevention Registry (APR) and the Brain Health Registry (BHR) are using the Internet to compile listings of suitable participants.
The APR is dedicated to uniting Alzheimer’s researchers with individuals interested in participating in clinical trials. The Phoenix-based non-profit organization also educates the public on Alzheimer’s and prevention of the disease. The Brain Health Registry is a web-based research study led by medical researchers at the University of California, San Francisco. Participants complete online questionnaires and tests that provide researchers with information regarding an individual’s health, lifestyle, and cognitive function. The collected data is used to create a listing of potential participants for Alzheimer’s studies.
Using Genetic Testing to Recruit Alzheimer’s Study Participants
GeneMatch is a program led by the Banner Alzheimer’s Institute in the Phoenix area that is part of the APR. The purpose of this national program is to recruit participants for research on Alzheimer’s disease by using genetic testing to match qualified volunteers with research studies. According to their website, 80% of research studies on the disease aren’t completed on time due to a lack of volunteers.
Anyone can register to be part of GeneMatch as long as they live in the United States and are between the ages of 55 and 75. In addition, participants cannot have a diagnosis of cognitive impairment, Alzheimer’s, or dementia.
“We hold local swabbing parties, where the GeneMatch sign-up rate is 95%,” Pierre Tariot, MD, Internal Medicine and Psychiatry, and Director of Banner Alzheimer’s Institute, said in the BRF article. “Jeffrey Cummings calls them Swab-a-Paloozas.”
GeneMatch screens individuals for the Apolipoprotein E (ApoE) and the ApoE-e4 allele which increases the risk for Alzheimer’s disease and is associated with earlier onset of memory loss and other symptoms. At this time, it is not known how this allele is related to the risk of getting the disease, but researchers have discovered the brain tissue of affected individuals have an increased number of protein clumps called amyloid plaques. A buildup of these plaques may lead to the death of neurons and the presence of Alzheimer’s symptoms.
“I spend a lot of time in my community doing outreach. People are very interested and receptive,” said Salloway, who recently hosted a swabbing party for GeneMatch. “At events, I ask everyone to tell five other people about what they learned, and to host swabbing parties themselves.”
The DNA samples obtained by GeneMatch are analyzed by a Clinical Laboratory Improvement Amendments (CLIA) certified laboratory. Over the past two years, GeneMatch has tested over 45,000 individuals for the ApoE-e4 allele and were able to identify 1,000 homozygote and 9,000 heterozygote carriers.
Lack of Diversity Among Study Participants
A paper published in September 2017 by Jeffrey Cummings, MD, Director of the Cleveland Clinic Lou Ruvo Center for Brain Health in Las Vegas, estimated the number of participants currently needed for Alzheimer’s research is over 55,000. Clinical trials for Alzheimer’s need volunteers who have little or no symptoms of the illness and locating such interested individuals can be complicated.
Jeffrey Cummings, MD (above), is Medical Director at Lou Ruvo Center for Brain Health in Las Vegas. In an interview with Drug Discovery and Development, Cummings said, “There is a huge problem of recruitment for many diseases throughout the nation. The problem goes beyond Alzheimer’s disease; there is a general lack of awareness by the public of either the availability or the importance of clinical trials.” (Photo copyright: Jerry Henkel/Las Vegas Review-Journal.)
Additional obstacles that face Alzheimer’s researchers are the lack of diversity among volunteers for their studies. The participants in GeneMatch are 78% female and there is little representation of African-American and Latino minorities.
“It’s not easy to get healthy individuals to join, and those who do are predominantly highly educated, white, and female,” Jessica Langbaum, PhD, Principal Scientist at Banner Alzheimer’s Institute, said in the BRF article. “That’s okay if the women are the health-info gatherers and send their men for trials, but it will be a problem if we cannot get men into studies.”
Delivering ApoE Genotype Results at Events
Technology that could help locate participants for Alzheimer’s research at open “Swab-a-Palooza” events include a small ApoE analyzer called the Spartan Cube. The small molecular diagnostic device, manufactured by Ottawa-based Spartan Bioscience, Inc., can deliver an ApoE genotype result in less than an hour. The gadget is perfect for outreach gatherings, as people can learn their ApoE genotype while at an event. At this time, the Spartan Cube is used only for research purposes and is not CLIA approved.
The paper by Cummings was a topic of discussion at the Clinical Trials on Alzheimer’s Disease (CTAD), which was held in November in Boston. The CTAD is an annual conference for Alzheimer’s disease researchers to meet and share information about the disease with each other. The 11th CTAD conference will take place in Barcelona, Spain, in October of this year.
More than five million people are living with Alzheimer’s disease in the United States and this number could reach 16 million by 2050, according to the Alzheimer’s Association. It is the sixth leading cause of death in the US and cost the nation $259 billion in 2017. It’s estimated that the costs associated with the disease could reach $1.1 trillion by 2050, which makes finding volunteers for research studies an important endeavor.
A university research team and a global diagnostics company simultaneously but independently unveil two new tests that accurately identify people predisposed to Alzheimer’s at earlier stages in the disease
Medical laboratory scientists and clinical pathologists have long awaited an accurate and clinically-useful test for the predisposition and early diagnosis of Alzheimer’s disease. Now comes pioneering efforts from two organizations that suggest real progress is being made.
One organization is an academic center and the other is anin vitro company. It was a research team at Rowan University School of Osteopathic Medicine (RowanSOM) that announced development of the first blood test to use the body’s own immune system to detect mild cognitive impairment (MCI), an early stage of Alzheimer’s disease.
