An assay using mass spectrometry could go to clinical trial within two years
Dark Daily has regularly observed that humans generate a variety of volatile substances—particularly in breath—which can be used for diagnostic purposes. But what if people, like certain trained animals, could smell the presence of disease before the onset of symptoms? What types of clinical laboratory testing biomarkers could be developed based on human-generated volatile organic compounds?
Researchers at the University of Manchester (UM) in the United Kingdom (UK) say their “breakthrough” test to diagnose Parkinson’s disease “can diagnose disease from skin swabs in three minutes,” according to a university press release.
Perdita Barran, PhD (right), head of the University of Manchester research team that developed the mass spectrometry Parkinson’s test, is shown above with Joy Milne (left), the retired nurse from Scotland who inspired Barran’s team to develop a new Parkinson’s biomarker and method for identifying it. “We are tremendously excited by these results which take us closer to making a diagnostic test for Parkinson’s Disease that could be used in clinic,” she said in a press release. A viable clinical laboratory test for Parkinson’s disease is greatly needed, as more than 10 million people worldwide currently live with the neurodegenerative disorder. (Photo copyright: University of Manchester.)
Using Mass Spectrometry to Analyze Sebum
The UM scientists hypothesized that the smell could be due to sebum, a light oily substance on skin that was going through a chemical change due to the Parkinson’s disease, Hull Daily Mail explained.
Increased sebum, which is produced by the sebaceous glands, is a hallmark of Parkinson’s, the researchers noted.
Their new method involves analysis of sebum using mass spectrometry, according to the JACS AU paper. The method, the researchers claim, makes it possible to diagnose Parkinson’s disease from skin swabs in three minutes.
“There are no cures for Parkinson’s, but a confirmatory diagnosis would allow [Parkinson’s patients] to get the right treatment and get the drugs that will help to alleviate their symptoms,” Perdita Barran, PhD, told the Hull Daily Mail. Barran is Chair of Mass Spectrometry in the Department of Chemistry and Director of the Michael Barber Centre for Collaborative Mass Spectrometry at UM’s Manchester Institute of Biotechnology. “What we are now doing is seeing if (hospital laboratories) can do what we’ve done in a research lab in a hospital lab,” she added.
Sebum Analyzed with Mass Spectrometry
Parkinson’s disease—the world’s fastest growing neurodegenerative disorder—needs “robust biomarkers” that could advance detection and head off onset of motor symptoms such as tremor, rigidity, and postural instability, the researchers note in their paper.
Their recent study builds on earlier 2019 findings they published in ACS Central Science about volatile compounds in sebum possibly being used as Parkinson’s biomarkers.
“Sebum is an underexplored biofluid, which is readily obtained from non-invasive skin swabs, which primarily consists of a mixture of triglycerides, cholesterol, free fatty acids, waxy esters, and squalene,” the researchers explained in their JACS AU paper.
The scientists sought, “to develop a method to analyze sebum in its native state to facilitate rapid assessment of the Parkinson’s disease status. Paper spray ionization mass spectrometry, which allows the direct analysis of compounds from paper, has previously been demonstrated to detect small molecules from unprocessed biofluids, such as blood and urine, but not to date with sebum,” they wrote.
The UM researchers used mass spectrometry to analyze sebum collected on cotton swabs from the backs of 79 people with Parkinson’s and 71 healthy individuals, BBC Scotland News reported.
Depanjan Sarkar, PhD, Research Associate, University of Manchester, further explained the technique in the UM news release:
Sebum is taken from the swab to filter paper cut in a triangle.
Using a solvent and voltage, sebum compounds transfer into the mass spectrometer.
“When we did this, we found more than 4,000 unique compounds of which 500 are different between people with Parkinson’s compared to the control participants,” Sarkar said.
Fatty Acids Make Assay Possible
Could fatty acids pave the way to an assay? The UM researchers believe so.
“We have identified two classes of lipids, namely [triglycerides] and diglycerides, as components of human sebum that are significantly differentially expressed in PD,” the researchers wrote in JACS AU. “Non-invasive sampling followed by PS-IM-MS [paper spray-ion mobility–mass spectrometry] analysis targeting these compounds could provide an inexpensive assay to support clinical phenotyping for the confirmatory diagnosis of Parkinson’s disease.”
A clinical trial for their test, which costs about $20, may be done within two years in Manchester area, the Daily Mail reported.
When Dark Daily reported in 2020 on Joy Milne’s unique ability to smell her husband’s Parkinson’s disease before it was formally diagnosed, we predicted a diagnostic test for Parkinson’s may be years away. And here it is, albeit with regulatory clearance needed following clinical trials.
It may in fact be possible to leverage sebum analysis to detect other diseases, the UM researchers noted.
For diagnostics developers, this story of Joy Milne and her husband Les Milne is a useful example of how, in tracking the life of a specific patient with a specific disease and close family members, researchers were able to identify a new class of biomarkers that could be used in a diagnostic assay.
It will be interesting to follow the University of Manchester researchers in their quest for a diagnostic mass spectrometry clinical laboratory test for Parkinson’s disease. According to Parkinson’s Foundation statistics, about 10 million people worldwide live with the neurodegenerative disorder. Such a new diagnostic test could be vitally important to medical laboratory care, and to patients and their families.
She worked with researchers at the University of Manchester in England to identify volatile biomarkers for Parkinson’s disease that may lead to first noninvasive screening
Clinical pathologists and medical laboratories are used to working with certain biological indicators that drive diagnostics and clinical laboratory testing. Mostly, those biomarkers are contained within various liquid samples, such as blood and urine. But what if a person’s odor could accurately predict risk for certain diseases as well?
Joy Milne, a retired nurse from Perth, Scotland, is the women whose heightened sense of smell enabled her to detect her husband’s Parkinson’s a decade before he was diagnosed with the disease.
Of course, Milne did not know at the time that what she was smelling was in fact a disease. She told NPR that she first noticed that her husband’s smell had changed from “his lovely male musk smell,” which she’d noticed when they first met, into “this overpowering sort of nasty yeast smell.”
Frequent washing did not remove the odor and as time went on the smell became stronger. When aspects of her husband’s personality and sleep habits also began to change, Joy convinced her husband, Les Milne, an anesthetist, to seek a diagnosis, thinking he had a brain tumor. Les was diagnosed with Parkinson’s disease.
It was 20 years later, when the Milnes attended a Parkinson’s disease support group, that Joy recognized the same distinctive smell she had noticed on Les on the other members of the group. That’s when the Milnes first realized Joy’s heightened sense of smell was something quite unique and possibly unprecedented.
Retired nurse Joy Milne (above) of Perth, Scotland, has an uncanny ability to diagnose Parkinson’s disease based on her highly sensitive sense of smell. Before her husband was diagnosed with the disease, she noticed a change in his smell. When she later recognized the same distinct odor among participants in a Parkinson’s support group, the Milnes asked scientists to investigate. (Photo copyright: NPR.)
Dogs Can Do It, Why Not Humans?
The concept that a disease gives off an aroma that can be detected by humans or animals is not far-fetched. As far back as 2013, Dark Daily was writing about such research. For example, in “C. diff-sniffing Beagle Dog Could Lead to Better Infection Control Outcomes in Hospitals and Nursing Homes,” we wrote about one hospital’s innovative approach to early detection of Clostridium difficile (C. diff) infection using a two-year-old beagle named Cliff that was faster at detecting certain infections than standard clinical laboratory tests used daily in hospitals throughout the world.
Thus, when the Milnes approached Dr. Kunath about Joy’s ability to “smell” Parkinson’s, they were on solid ground. However, he was not convinced.
“It just didn’t seem possible,” Kunath told NPR. “Why should Parkinson’s have an odor? You wouldn’t think neurodegenerative conditions such as Parkinson’s, or Alzheimer’s, would have an odor.”
But Kunath reconsidered after learning of research presented during the Experimental Biology annual meeting in 2019, which showed canines can in fact effectively detect lung cancer biomarkers in blood serum.
He contacted Milne and devised an experiment in which a group of people who had Parkinson’s disease, and another group that did not, would take home t-shirts and wear them overnight. The next day the t-shirts were assigned randomized numbers and put in a box. Milne then smelled each of the 12 t-shirts and assigned each one a score.
Kunath told NPR that Milne was “incredibly accurate.” She had misidentified only one shirt worn by a person in the control group. She incorrectly diagnosed the person with Parkinson’s. However, three months later, that man was in fact diagnosed with Parkinson’s, meaning Joy’s accuracy was 12-for-12.
“She was telling us this individual had Parkinson’s before he knew, before anybody knew,” Kunath told the BBC Scotland.
In an ensuing study, “Discovery of Volatile Biomarkers of Parkinson’s Disease from Sebum,” published in 2019 in ACS Central Science, the researchers describes the “distinct volatiles-associated signature” of Parkinson’s disease, which includes “altered levels of perillic aldehyde and eicosane, the smell of which was then described as being highly similar to the scent of Parkinson’s disease by our ‘Super Smeller.’” Joy Milne co-authored the study.
The concept of the human body producing volatile chemicals that can serve as biomarkers for disease or illness is not new to clinical laboratory professionals. The urea breath test, for example, to detect the presence of active H. pylori bacteria in the stomach is a longstanding example of one such diagnostic test.
Barran led a larger Manchester University study which was published on ChemRxiv, titled, “Sebum: A Window into Dysregulation of Mitochondrial Metabolism in Parkinson’s Disease,” which was funded by a Michael J. Fox research grant (12921). Barran and her research team, which included Milne, “found 10 compounds linked to Parkinson’s by using mass spectrometry and other techniques” on skin sebum samples, reported NPR.
“We really want to know what is behind this and what are the molecules. And then, [determine if] the molecules [can] be used as some sort of diagnostic test,” Kunath told NPR.
A Definitive, Noninvasive Test for Parkinson’s?
The UK researchers discovered in the skin sebum volatile biomarkers of Parkinson’s disease that may lead to development of the first definitive test for the disease.
Katherine Crawford, Scotland Director of Parkinson’s UK, aka the Parkinson’s Disease Society of the United Kingdom, said a noninvasive diagnostic test for Parkinson’s would be game changing.
“We still effectively diagnose it today the way that Dr. James Parkinson diagnosed it in 1817, which is by observing people and their symptoms,” Crawford told BBC Scotland. “A diagnostic test like this could cut through so much of that, enable people to go in and see a consultant, have a simple swab test and come out with a clear diagnosis of Parkinson’s.”
“It wouldn’t have happened without Joy,” Barran told BBC Scotland. “For all the serendipity, it was Joy and Les who were absolutely convinced that what she could smell would be something that could be used in a clinical context, and so now we are beginning to do that.”
A viable, working diagnostic test based on these new biomarkers may be years away. Nevertheless, clinical laboratory leaders will want to follow the ongoing efforts toward development of a noninvasive swab test for Parkinson’s disease. Such a breakthrough would revolutionize Parkinson’s testing and might never have come to light without the persistence of a woman with an extremely sensitive sense of smell.
