A new blood test may predict the onset of psychotic disorders years in advance, during childhood

By Rich Haridy

An international team of researchers has used machine learning to produce a novel blood test that can predict a young person’s risk of developing a psychotic disorder, such as schizophrenia, years before the condition develops.

Only around a quarter of young people who display mild, transitory psychotic symptoms at an early age ultimately go on to develop a serious psychotic disorder. Schizophrenia, for example, is generally not clinically diagnosed until a person reaches their twenties. However, the condition is known to present a number of signs and symptoms than can precede the full-blown psychotic episodes often needed for clinical diagnosis.

This early pre-clinical phase of a psychotic disorder is often referred to as the prodromal stage. In the case of schizophrenia, prodromal symptoms appear in nearly three quarters of patients up to five years before the first episode of psychosis occurs.

David Cotter, a molecular psychiatrist from the Royal College of Surgeons in Ireland and senior author on the new study, suggests early detection of those most at risk of developing psychotic disorders is vital for administering preventative treatments.

“Ideally, we would like to prevent psychotic disorders, but that requires being able to accurately identify who is most at risk,” says Cotter.

The new study first looked at blood samples from a number of 12-year-olds classified as at a clinically high-risk of psychosis. Over recent years several tools have been developed to identify adolescent subjects at the highest risk of developing psychosis.

The 12-year-old subjects were followed until around the age of 18, so the researchers were able to differentiate blood samples between those who went on to suffer a psychotic episode and those who didn’t. Using machine learning, the researchers homed in on a unique pattern of proteins that distinguished those who ultimately went on to develop a psychotic disorder.

Ten particular proteins were identified as most predictive, and the test was subsequently validated in a separate dataset. Using the most accurate protein pattern, the researchers were able to correctly determine which high-risk subjects would go on to develop a psychotic disorder by the age of 18 with a 93-percent accuracy.

The test was less accurate in predicting those high-risk 12-year-olds that did not go on to develop a psychosis by the age of 18. However, considering only between 16 and 35 percent of young people considered at clinical high risk ultimately transition to a full psychotic disorder, even this low level of accuracy could be useful in stratifying those younger patients more likely to develop psychosis.

“Our research has shown that, with help from machine learning, analysis of protein levels in blood samples can predict who is at truly at risk and could possibly benefit from preventive treatments,” says Cotter. “We now need to study these markers in other people at high risk of psychosis to confirm these findings.”

Another compelling insight offered by this new study is the finding that many of these protein markers predicting psychosis are linked with inflammatory processes. There is a small, but burgeoning, body of study finding links between psychosis and autoimmune conditions, suggesting systemic inflammation can influence a number of psychiatric illnesses.

The new research was published in the journal JAMA Psychiatry.

https://www.eurekalert.org/pub_releases/2020-08/r-sub082620.php

Experimental Blood Test Could Flag Alzheimer’s


New studies show that elevated levels of a form of tau called p-tau217 can accurately distinguish Alzheimer’s disease from other forms of dementia, and perhaps even predict it.

by Kerry Grens

Three studies presented at the Alzheimer’s Association International Conference this week describe the performance of blood tests used to diagnose, and even predict, Alzheimer’s disease using circulating levels of a form of tau protein called p-tau217. The largest assessment of this approach, which included 1,402 participants, showed that circulating p-tau217 levels worked just as well at detecting Alzheimer’s as standard PET scans and tests of cerebrospinal fluid.

“This blood test very, very accurately predicts who’s got Alzheimer’s disease in their brain, including people who seem to be normal,” Michael Weiner, an Alzheimer’s disease researcher at the University of California, San Francisco, who was not involved in the study, tells The New York Times. “It’s not a cure, it’s not a treatment, but you can’t treat the disease without being able to diagnose it. And accurate, low-cost diagnosis is really exciting, so it’s a breakthrough.”

A blood test could help identify people on track to develop Alzheimer’s early on—and perhaps get them enrolled in drug trials aimed at finding an effective treatment for the disease. Scientists have pursued a number of potential circulating biomarkers, such as amyloid-β, to find those that can reliably diagnose Alzheimer’s disease or predict its development, but to date none have come to market.

High levels of tau or its phosphorylated form, p-tau, have emerged as promising biomarker candidates because they may indicate the presence of damaging structures known as neurofibrillary tangles in the brain.

The large study on one type of p-tau, p-tau217, published in JAMA July 28 to coincide with the presentation at the meeting, was a collection of three experiments using a blood test developed by Eli Lilly (some of the coauthors work for the company). In one assessment of several hundred Swedes, the test accurately distinguished patients who had Alzheimer’s from those with other forms of dementia with 89–98 percent accuracy. “That’s pretty good. We’ve never seen that” precision before, Maria Carrillo, the Alzheimer’s Association’s chief science officer, tells the Associated Press.

In another assessment of the Eli Lilly test, which included hundreds of related individuals, some of whom have a gene that causes Alzheimer’s, p-tau217 levels in the blood aligned with the genetics, even decades before cognitive impairment is likely to begin.

Another study presented at the conference found a p-tau217 blood test could accurately distinguish Alzheimer’s patients from those with frontotemporal lobar degeneration, according to a conference press release. And a third presentation of a study by Suzanne Schindler of Washington University in St. Louis and her colleagues reported that circulating p-tau217 was superior to another form that’s been studied as a potential biomarker, p-tau181, as a proxy for amyloid accumulation in the brain.

“I personally find it very reassuring that these different groups are using different types of assays and getting the same result,” Schindler tells the Times. “It looks real. It looks like 217 has tremendous promise as a blood test for Alzheimer’s disease, and it is likely to correspond with the symptoms.”

Speaking to The Guardian, Clive Ballard, who studies age-related disease at the University of Exeter Medical School and who was not involved in these projects, says, “further validation in people from more routine clinical settings are still needed, and a lot of work will be needed to achieve standardisation of the test across laboratories—so it could still be at least five years before we see an accurate blood biomarker test for dementia in the clinic.”

https://www.the-scientist.com/news-opinion/experimental-blood-test-could-flag-alzheimers-67779?utm_campaign=TS_DAILY%20NEWSLETTER_2020&utm_medium=email&_hsmi=92321648&_hsenc=p2ANqtz-8ayk91AfO8kNKldfK3kfssyQf2GRuKPsOimQKjhl3hz5Ap-KFfFI0molaN5LwimzBJw9JHyX8TCowcon5V50G5hr5ErA&utm_content=92321648&utm_source=hs_email

Chemists develop foolproof new test to track the fats we eat


Philip Britz-McKibbin, Professor of Chemistry & Chemical Biology, McMaster University Credit: JD Howell, McMaster University

A team of researchers at McMaster University has developed a reliable and accurate blood test to track individual fat intake, a tool that could guide public health policy on healthy eating.

Establishing reliable guidelines has been a significant challenge for nutritional epidemiologists until now, because they have to rely on study participants faithfully recording their own consumption, creating results that are prone to human error and selective reporting, particularly when in the case of high-fat diets.

For the study, published in the Journal of Lipid Research, chemists developed a test, which detects specific non-esterified fatty acids (NEFAs), a type of circulating free fatty acid that can be measured using a small volume of blood sample.

“Epidemiologists need better ways to reliably assess dietary intake when developing nutritional recommendations,” says Philip Britz-McKibbin, professor in the Department of Chemistry & Chemical Biology at McMaster University and lead author of the study.

“The food we consume is highly complex and difficult to measure when relying on self-reporting or memory recall, particularly in the case of dietary fats. There are thousands of chemicals that we are exposed to in foods, both processed and natural,” he says.

The study was a combination of two research projects Britz-McKibbin conducted with Sonia Anand in the Department of Medicine and Stuart Phillips in the Department of Kinesiology.

Researchers first assessed the habitual diet of pregnant women in their second trimester, an important development stage for the fetus. The women, some of whom were taking omega-3 fish oil supplements, were asked to report on their average consumption of oily fish and full-fat dairy and were then tested with the new technology. Their study also monitored changes in omega-3 NEFAs in women following high-dose omega-3 fish oil supplementation as compared to a placebo.

Researchers were able to prove that certain blood NEFAs closely matched the diets and/or supplements the women had reported, suggesting the dietary biomarkers may serve as an objective tool for assessment of fat intake.

“Fat intake is among the most controversial aspects of nutritional public health policies given previously flawed low-fat diet recommendations, and the growing popularity of low-carb/high-fat ketogenic based diets” says Britz-McKibbin. “If we can measure it reliably, we can begin to study such questions as: Should pregnant women take fish oil? Are women deficient in certain dietary fats? Does a certain diet or supplement lead to better health outcomes for their babies?”

Researchers plan to study what impact NEFAs and other metabolites associated with dietary exposures during pregnancy, might have on childhood health outcomes in relation to the obesity, metabolic syndrome and chronic disease risk later in life.

https://medicalxpress.com/news/2020-05-chemists-foolproof-track-fats.html

We’re One Step Closer to a Blood Test that Predicts When a Person Will Die

By Alice Park

While death is inevitable, knowing when it will come isn’t necessarily, and scientists have been trying to develop a test that could reliably and easily predict how long a person will live — or, more technically, how healthy they are and therefore how vulnerable they might be to major mortality risk factors. Blood tests are the most likely avenue to such a test, since it’s easy to obtain blood samples and labs equipped to handle them are common.

The latest effort is described in a new paper published in Nature Communications, by a team led by Joris Deelen, postdoctoral researcher at the Max Planck Institute for the Biology of Aging and P. Eline Slagboom, head of molecular epidemiology at Leiden University Medical Center. The researchers report that, in a group of more than 44,000 healthy patients, their blood test was around 80% accurate in predicting mortality risk within five to 10 years.

The patients, who ranged in age from 18 to 109 years, provided blood samples and had their health events tracked for up to 16 years. The researchers analyzed a group of 226 so-called metabolites, or by-products of things that various cells and tissues in the body pour into the blood stream for circulation and removal. From this collection of markers, the team narrowed down the list to 14 that they determined could together, and along with the person’s sex, provide a pretty good picture of each person’s health risk, and, by association, their risk of dying in the next five to 10 years. They accomplished this by comparing those who died during the study to those who did not and isolating which agents in their blood differed to statistically significant amounts. The link between the final 14 factors and mortality remained strong even after the scientists accounted for potential confounding factors that also affect survival such as age, sex, and cause of death.

“We want to tackle the vulnerability of people’s health that is hidden and that doctors cannot see from the outside,” says Slagboom. “I am still surprised by the fact that in a group of people you can take one blood sample at one point of time in their life, and that would say anything meaningful about their five to 10 year mortality risk.”

Both Deelen and Slagboom stress that the test is not ready yet for doctors to use in the clinic with their patients, but that it does establish a foundation for one down the road. An eventual test could be most useful at first in assessing older patients and guiding treatment decisions, since the 14 metabolites represent a range of processes including the breakdown of fat and glucose, inflammation and fluid balance in the body, that impact a range of chronic ailments, as well as a person’s ability to recover from illness or injury.

Researchers at Leiden University are currently studying the test to see if it can help doctors predict which patients with hip fractures are more likely to develop complications during their recovery after surgery. Another study is looking at whether the test can predict which people with kidney failure are more likely to develop dementia or side effects like delirium as a result of their treatment; this information could help doctors to better adjust dosage and treatment decisions.

The researchers are also hoping to work with large databanks around the world to further validate the findings. “We see this as a foundation,” says Slagboom, “we do not see this test as an endpoint.”

https://time.com/5656767/blood-test-longevity/