New clinical laboratory test could replace conventional spinal tap for diagnosing neurodegenerative disease
In a proof-of-concept study, University of Pittsburgh (Pitt) scientists validated a clinical laboratory test that measures more than 100 different genetic sequences associated with Alzheimer’s disease. The Pitt researchers believe the new diagnostic platform could help clinicians “capture the multifaceted nature of Alzheimer’s pathology and streamline early disease diagnostics,” according to a news release.
Clinical laboratory blood tests that detect biomarkers such as phosphorylated tau protein (pTau) have emerged in studies as diagnostic possibilities for Alzheimer’s disease, which is traditionally diagnosed using a lumbar puncture (spinal tap) procedure.
In their paper, neuroscientist Thomas Karikari, PhD, Assistant Professor of Psychiatry at University of Pittsburgh, lead author of the study, and his research team acknowledged that progress has been made in detecting Alzheimer’s disease with blood-based biomarkers. However, they note that “two key obstacles remain: the lack of methods for multi-analyte assessments and the need for biomarkers for related pathophysiological processes like neuroinflammation, vascular, and synaptic dysfunction.”
The Pitt scientists believe the focus on so-called “classical Alzheimer’s blood biomarkers” limits exploration of neurodegenerative disease.
“Alzheimer’s disease should not be looked at through one single lens. Capturing aspects of Alzheimer’s pathology in a panel of clinically validated biomarkers would increase the likelihood of stopping the disease before any cognitive symptoms emerge,” said neuroscientist Thomas Karikari, PhD (above), Assistant Professor of Psychiatry, University of Pittsburgh, and lead author of the study in a news release. Should further studies prove Pitt’s research sound, clinical laboratories may have a replacement test for diagnosing neurodegenerative disease. (Photo copyright: University of Pittsburgh.)
On its website, Alamar Biosciences explains that the disease panel offers neurological researchers:
“Multiplexed analysis of 120 neuro-specific and inflammatory proteins from 10 µl of plasma or CSF (cerebrospinal fluid).
Detection of “critical biomarkers—including pTau-217, GFAP (glial fibrillary acidic protein), NEFL (neurofilament light polypeptide) and alpha-synuclein.”
The NULISAseq test works with “a proprietary sequential immunocomplex capture and release mechanism and the latest advances in next-generation sequencing,” according to the company.
Inside Precision Medicine noted that the Alamar Biosciences assay enabled Pitt scientists to detect:
Biomarkers (usually found in CSF) “correlating with patients’ amyloid positivity status and changes in amyloid burden over time,” and,
Biomarkers including “neuroinflammation, synaptic function, and vascular health, which had not previously been validated in blood samples.”
“The performance of the NULISA platform was independently validated against conventional assays for classic Alzheimer’s biomarkers for each sample. Biomarker profiles over two years were also compared with imaging-based measures of amyloid, tau, and neurodegeneration,” LabMedica reported.
Opportunity to Track Alzheimer’s
Karikari sees the diagnostic platform being used to track individuals’ blood biomarker changes over time.
In their Molecular Neurodegeneration paper, the Pitt researchers wrote, “These (results) were not limited to markers such as pTau217, p-Tau231, p-Tau181, and GFAP, the elevation of which have consistently shown strong associations with brain Aβ [amyloid beta] and/or tau load, but included novel protein targets that inform about the disease state of the individual in different pathological stages across the biological Alzheimer’s disease continuum.”
About seven million Americans are affected by Alzheimer’s disease, according to the Alzheimer’s Association, which estimated that figure will grow to 13 billion by 2050.
Further studies by Karikari may include larger samples and greater diversity among the people studied, Inside Precision Medicine noted.
“[Karikari’s] lab is developing a predictive model that correlates biomarker changes detected using NULISAseq with brain autopsy data and cognitive assessments collected over the course of several years. Their goal is to identify blood biomarkers that can help stage the disease and predict its progression, both for decision-making around clinical management and treatment plans,” the Pitt news release states.
The Pitt scientists have developed a multiplex test that works with 100 different genetic sequences associated with Alzheimer’s. Such advances in the understanding of the human genome are giving scientists the opportunity to combine newly identified gene sequences that have a role in specific disease states.
In turn, as further studies validate the value of these biomarkers for diagnosing disease and guiding treatment decisions, clinical laboratories will have new assays that deliver more value to referring physicians and their patients.
The NIH’s Researching COVID to Enhance Recovery (RECOVER) Initiative used a cohort study of more than 10,000 individuals with and without previous COVID-19 diagnoses and compared samples using 25 common laboratory tests in hopes a useful biomarker could be identified. They were unsuccessful.
Long COVID—or PASC—is an umbrella term for those with persistent post-COVID infection symptoms that negatively impact quality of life. Though it affects millions worldwide and has been called a major public health burden, the NIH/Langone study scientists noted one glaring problem: PASC is defined differently in the major tests they studied. This makes consistent diagnoses difficult.
The study brought to light possible roadblocks that prevented biomarker identification.
“This study is an important step toward defining long COVID beyond any one individual symptom,” said study author Leora Horwitz, MD (above), director of the Center for Healthcare Innovation and Delivery Science and co-principal investigator for the RECOVER CSC at NYU Langone, in a Langone Health news release. “This definition—which may evolve over time—will serve as a critical foundation for scientific discovery and treatment design.” In the future, clinical laboratories may be tasked with finding combinations of routine and reference tests that, together, enable a more precise and earlier diagnosis of long COVID. (Photo copyright: Yale School of Medicine.)
NIH/Langone Study Details
“The study … examined 25 routinely used and standardized laboratory tests chosen based on availability across institutions, prior literature, and clinical experience. These tests were conducted prospectively in laboratories that are certified by the Clinical Laboratory Improvement Amendments (CLIA). The samples were collected from 10,094 RECOVER-Adult participants, representing a diverse cohort from all over the US,” Inside Precision Medicine reported.
However, the scientists found no clinical laboratory “value” among the 25 tests examined that “reliably indicate previous infection, PASC, or the particular cluster type of PASC,” Inside Precision Medicine noted, adding that “Although some minor differences in the results of specific laboratory tests attempted to differentiate between individuals with and without a history of infection, these findings were generally clinically meaningless.”
“In a cohort study of more than 10,000 participants with and without prior SARS-CoV-2 infection, we found no evidence that any of 25 routine clinical laboratory values provide a reliable biomarker of prior infection, PASC, or the specific type of PASC cluster. … Overall, no evidence was found that any of the 25 routine clinical laboratory values assessed in this study could serve as a clinically useful biomarker of PASC,” the study authors wrote in Annals of Internal Medicine.
In addition to a vague definition of PASC, the NIH/Langone researchers noted a few other potential problems identifying a biomarker from the research.
“Use of only selected biomarkers, choice of comparison groups, if any (people who have recovered from PASC or healthy control participants); duration of symptoms; types of symptoms or phenotypes; and patient population features, such as sex, age, race, vaccination status, comorbidities, and severity of initial infection,” could be a cause for ambiguous results, the scientists wrote.
Future Research
“Understanding the basic biological underpinnings of persistent symptoms after SARS-CoV-2 infection will likely require a rigorous focus on investigations beyond routine clinical laboratory studies (for example, transcriptomics, proteomics, metabolomics) to identify novel biomarkers,” the study authors wrote in Annals of Internal Medicine.
“Our challenge is to discover biomarkers that can help us quickly and accurately diagnose long COVID to ensure people struggling with this disease receive the most appropriate care as soon as possible,” said David Goff, MD, PhD, director of the division of cardiovascular sciences at the NIH’s National Heart, Lung, and Blood Institute, in an NHLBI news release. “Long COVID symptoms can prevent someone from returning to work or school, and may even make everyday tasks a burden, so the ability for rapid diagnosis is key.”
“Approximately one in 20 US adults reported persisting symptoms after COVID-19 in June 2024, with 1.4% reporting significant limitations,” the NIH/Langone scientists wrote in their published study.
Astute clinical laboratory scientists will recognize this as possible future diagnostic testing. There is no shortage of need.
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.
