New non-invasive test could replace traditional painful spinal taps and clinical laboratory fluid analysis for diagnosis of Parkinson’s disease
Scientists at AXIM Biotechnologies of San Diego have added another specimen that can be collected non-invasively for rapid, point-of-care clinical laboratory testing. This time it is tears, and the diagnostic test is for Parkinson’s disease (PD).
The new assay measures abnormal alpha-synuclein (a-synuclein), a protein that is a biomarker for Parkinson’s, according to an AXIM news release which also said the test is the first rapid test for PD.
“The revolutionary nature of AXIM’s new test is that it is non-invasive, inexpensive, and it can be performed at a point of care. It does not require a lumbar puncture, freezing, or sending samples to a lab. AXIM’s assay uses a tiny tear drop versus a spinal tap to collect the fluid sample and the test can be run at a doctor’s office with quantitative results delivered from a reader in less than 10 minutes,” the news release notes.
“Furthermore, emerging evidence shows that a-synuclein assays have the potential to differentiate people with PD from healthy controls, enabling the potential for early identification of at-risk groups,” the news release continues. “These findings suggest a crucial role for a-synuclein in therapeutic development, both in identifying pathologically defined subgroups of people with Parkinson’s disease and establishing biomarker-defined at-risk cohorts.”
This is just the latest example of a disease biomarker that can be collected noninvasively. Other such biomarkers Dark Daily has covered include:
“With this new assay, AXIM has immediately become a stakeholder in the Parkinson’s disease community, and through this breakthrough, we are making possible new paradigms for better clinical care, including earlier screening and diagnosis, targeted treatments, and faster, cheaper drug development,” said John Huemoeller, CEO, AXIM (above), in a news release. Patients benefit from non-invasive clinical laboratory testing. (Photo copyright: AXIM Biotechnologies.)
Fast POC Test versus Schirmer Strip
AXIM said it moved forward with its novel a-synuclein test propelled by earlier tear-related research that found “a-synuclein in its aggregated form can be detected in tears,” Inside Precision Medicine reported.
But that research used what AXIM called the “outdated” Schirmer Strip method to collect tears. The technique involves freezing tear samples at -80 degrees Celsius (-112 Fahrenheit), then sending them to a clinical laboratory for centrifugation for 30 minutes; quantifying tear protein content with a bicinchoninic acid assay, and detecting a-synuclein using a plate reader, AXIM explained.
Alternatively, AXIM says its new test may be performed in doctors’ offices and offers “quantitative results delivered from a reader in less than 10 minutes.”
“Our proven expertise in developing tear-based diagnostic tests has led to the development of this test in record speed, and I’m extremely proud of our scientific team for their ability to expand our science to focus on such an important focus area as Parkinson’s,” said John Huemoeller, CEO, AXIM in the news release.
“This is just the beginning for AXIM in this arena,” he added. “But I am convinced when pharmaceutical companies, foundations, and neurologists see how our solution can better help diagnose Parkinson’s disease in such an expedited and affordable way, we will be at the forefront of PD research, enabling both researchers and clinicians a brand-new tool in the fight against PD.”
One of those tests was “a lateral flow diagnostic for point-of-care use that measures the level of lactoferrin proteins in tear fluid, which work to protect the surface of the eye. … Axim said that low lactoferrin levels have also been linked to Parkinson’s disease and that the assay can be used alongside its alpha-synuclein test,” Fierce Biotech noted.
“It made sense to try and look at the proteinaceous [consisting of or containing protein] constituents of tear fluid,” Lew told Neurology Live. “Tear fluid is easy to collect. It’s noninvasive, inexpensive. It’s not like when you do a lumbar puncture, which is a much more involved ordeal. There’s risk of contamination with blood (saliva is dirty) issues with blood and collection. [Tear fluid analysis] is much safer and less expensive to do.”
In Biomarkers in Medicine, Lew et al noted why tears make good biomarkers for Parkinson’s disease, including “the interconnections between the ocular [eye] surface system and neurons affected in Parkinson’s disease.”
The researchers also highlighted “recent data on the identification of tear biomarkers including oligomeric α-synuclein, associated with neuronal degeneration in PD, in tears of PD patients” and discussed “possible sources for its release into tears.”
Future Clinical Laboratory Testing for Parkinson’s
Parkinson’s disease is the second most common neurodegenerative disorder after Alzheimer’s. It affects nearly one million people in the US. About 1.2 million people may have it by 2030, according to the Parkinson’s Foundation.
Thus, an accurate, inexpensive, non-invasive diagnostic test that can be performed at the point of care, and which returns clinical laboratory test results in less than 10 minutes, will be a boon to physicians who treat PD patients worldwide.
Clinical laboratory managers and pathologists may want to follow AXIM’s future research to see when the diagnostic test may become available for clinical use.
Studies presented at the Alzheimer’s Association International Conference point to the p-tau217 protein as an especially useful biomarker
Researchers disclosed a potentially useful biomarker for Alzheimer’s Disease at a major conference this summer. The good news for clinical laboratories is that the biomarker is found in blood. If further research confirms these early findings, medical laboratories could one day have a diagnostic test for this condition.
That possibility emerged from the Alzheimer’s Association International Conference (AAIC), which was held online July 27-31. Researchers presented findings from multiple studies that suggested blood/plasma levels of a protein known as phospho-tau217 (p-tau217) can indicate brain anomalies associated with Alzheimer’s.“Changes in brain proteins amyloid and tau, and their formation into clumps known as plaques and tangles, respectively, are defining physical features of Alzheimer’s disease in the brain,” states an AAIC press release. “Buildup of tau tangles is thought to correlate closely with cognitive decline. In these newly reported results, blood/plasma levels of p-tau217, one of the forms of tau found in tangles, also seem to correlate closely with buildup of amyloid.”
At present, “there is no single diagnostic test that can determine if a person has Alzheimer’s disease,” the association states on its website. Clinicians will typically review a patient’s medical history and conduct tests to evaluate memory and other everyday thinking skills. That may help determine that an individual has dementia, but not necessarily that Alzheimer’s is the cause.
“Currently, the brain changes that occur before Alzheimer’s dementia symptoms appear can only be reliably assessed by positron-emission tomography (PET) scans, and from measuring amyloid and tau proteins in [cerebrospinal] fluid (CSF),” the association states. “These methods are expensive and invasive. And, too often, they are unavailable because they are not covered by insurance or difficult to access, or both.”
In the AAIC press release, Alzheimer’s Association Chief Science Officer Maria C. Carrillo, PhD, said that a clinical laboratory blood test “would fill an urgent need for simple, inexpensive, non-invasive and easily available diagnostic tools for Alzheimer’s.
“New testing technologies could also support drug development in many ways,” she added. “For example, by helping identify the right people for clinical trials, and by tracking the impact of therapies being tested. The possibility of early detection and being able to intervene with a treatment before significant damage to the brain from Alzheimer’s disease would be game changing for individuals, families, and our healthcare system.”
However, she cautioned, “these are early results, and we do not yet know how long it will be until these tests are available for clinical use. They need to be tested in long-term, large-scale studies, such as Alzheimer’s clinical trials.”
The study, led by Oskar Hansson, MD, of Lund University in Sweden, included 1,402 participants. About half of these were enrolled in BioFINDER-2, an ongoing dementia study in Sweden. In this group, researchers were most interested in the test’s ability to distinguish Alzheimer’s from other neurodegenerative disorders that cause dementia.
Diagnostic accuracy was between 89% and 98%, the researchers reported, which was similar to the performance of PET imaging and CSF tests. P-tau217 was more accurate than magnetic resonance imaging (MRI) as well as other biomarkers, such as p-tau181.
“Today the majority of individuals with Alzheimer’s disease around the world do not get a timely diagnosis, which results in suboptimal symptomatic treatment and care,” Oskar Hansson, MD, said in an Eli Lilly news release. “With rising prevalence of Alzheimer’s disease, more patients will be evaluated in primary care and other clinics where CSF and PET biomarkers are not available. Blood-based biomarkers, like plasma p-tau217, together with digital tools for checking memory performance, such as smartphone-based apps, can considerably improve the diagnostic work-up of Alzheimer’s disease patients in such clinics.” (Photo copyright: Alzheimer’s Fund.)
Another cohort consisted of 81 participants in the Brain and Body Donation Program at Banner Sun Health Research Institute in Sun City, Ariz. In this program, elderly volunteers submit to periodic clinical assessments and agree to donate their organs and tissue for study after they die.
Here, the researchers’ primary goal was to determine the test’s ability to distinguish between individuals with and without Alzheimer’s. Researchers ran the p-tau217 test on plasma samples collected within 2.9 years of death and compared the results to postmortem examinations of the brain tissue. Accuracy was 89% in individuals with amyloid plaques and tangles, and 98% in individuals with plaques and more extensive tangles.
The third cohort consisted of 622 members of a large extended family in Colombia whose members share a genetic mutation that makes them susceptible to early-onset Alzheimer’s, The New York Times reported. Among the members, 365 were carriers of the mutation. In this group, levels of plasma p-tau217 increased by age, and “a significant difference from noncarriers was seen at age 24.9 years,” the researchers wrote in Jama Network. That’s about 20 years before the median age when mild cognitive impairment typically begins to appear in carriers.
Other Alzheimer Biomarker Studies Presented at AAIC
Suzanne Schindler, MD, PhD, a neurologist and instructor in the Department of Neurology at the Washington University School of Medicine (WUSM) in St. Louis, presented results of an Alzheimer’s Disease (AD) study that used mass spectrometry to analyze amyloid and p-tau variants in blood samples collected from participants. The researchers compared these with CSF and PET results and found that some of the of p-tau isoforms, especially p-tau217, had a strong concordance.
“These findings indicate that blood plasma Aβ and p-tau measures are highly precise biomarkers of brain amyloidosis, tauopathy, and can identify stages of clinical and preclinical AD,” stated an AAIC press release on the studies.
The WUSM researches launched the effort to develop and validate Alzheimer’s blood biomarkers called the Study to Evaluate Amyloid in Blood and Imaging Related to Dementia (SEABIRD) in April 2019. It runs through August 2023 and will seek to enroll more than 1,100 participants in the St. Louis area.
Another study presented at the conference compared the performance of p-tau217 and p-tau181 in distinguishing between Alzheimer’s and Frontotemporal Lobar Degeneration (FTLD), another condition that causes dementia. Study author Elisabeth Thijssen, MSc, of the UC San Francisco Memory and Aging Center reported that both biomarkers could be useful in differential diagnosis, but that p-tau217 was “potentially superior” for predicting a tau positive PET scan result.
For decades, physicians have wanted a diagnostic test for Alzheimer’s Disease that could identify this condition early in its development. This would allow the patient and the family to make important decisions before the onset of severe symptoms. Such a clinical laboratory test would be ordered frequently and thus would be a new source of revenue for medical laboratories.
