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By Nancy Lapid, Health Science Editor

Hello Health Rounds readers! Today we highlight a study that could lead to a blood test for identifying individuals at high risk of suicide, and potential treatments for them; and another study by researchers developing an inhaled test for early lung cancer that could one day prove invaluable in areas with limited access to CT scans. We also cover a study that identified bacteria and viruses living in the intestines that appear to prevent or lessen the affect of graft-versus-host disease following stem cell transplants.   

In breaking news, see these stories from our Reuters journalists: New York could be first state to offer prenatal paid leave to mothers; Canada says bulk importation not an effective solution to high drug prices in U.S.; Spain considers nationwide hospital mask rule, as flu, COVID hit Europe; CDC says JN.1 variant accounts for about 62% of U.S. COVID cases; and U.S. Supreme Court rejects challenge to California flavored tobacco ban.

Last year was the planet’s hottest – by a substantial margin – since record-keeping began in 1850 and was likely the world’s warmest in the last 100,000 years, the European Union’s Copernicus Climate Change Service said on Tuesday. Read more. REUTERS/Jorge Garcia

Blood tests might someday help identify patients with difficult-to-treat depression who are at higher risk for becoming suicidal, as well as help determine potential treatments, results of a new study suggest.

Researchers found changes in certain biochemicals in blood samples from those with depression not responding to treatment who were experiencing suicidal thoughts that allowed the scientists to distinguish them from healthy volunteers. The study included 99 people in each group.

Some of the metabolic markers identified in the study were lipid abnormalities. Other changes included deficiencies in compounds that are available as supplements, such as folate and carnitine, suggesting it might be possible to individualize depression treatment with these compounds, according to a report published in Translational Psychiatry.

“None of these metabolites are a magic bullet that will completely reverse somebody’s depression,” study leader Dr. Robert Naviaux of UC San Diego School of Medicine said in a statement. “(But) there may be things we can do to nudge the metabolism in the right direction to help patients respond better to treatment, and in the context of suicide, this could be just enough to prevent people from crossing that threshold.”

While the metabolic markers of suicidal ideation differed somewhat between men and women, in both sexes they included signals of dysfunctioning mitochondria, the “energy factories” inside cells.

“If we have 100 people who either don’t have depression or who have depression and suicidal ideation, we would be able to correctly identify 85-90 of those at greatest risk based on five metabolites in males and another 5 metabolites in females,” Naviaux said.

Mitochondria also play an important role in cell-to-cell communication. The researchers believe this function is particularly broken in people with suicidal ideation, with dozens of protective pathways over-activated in response to stress.

“Suicide attempts may actually be part of a larger physiological impulse to stop a stress response that has become unbearable at the cellular level,” Naviaux said.

An experimental inhalable lung cancer test may someday help detect early-stage tumors in patients with limited access to gold-standard computed tomography (CT), researchers say.

In mice with lung cancer, the test accurately detected tumors that would correlate with stage 1 or 2 cancer in humans, according to a report published in Science Advances.

Administered via inhalers or nebulizers, the test delivers minuscule “sensor” particles deep into the airways of the lungs.

Molecules in the tiny sensors are coated with pieces of DNA that separate themselves from the sensors when they encounter certain proteins in the lungs indicative of tumors. The pieces of DNA then enter the bloodstream and eventually accumulate in the urine, where they can be detected using a paper test strip.

The researchers next plan to analyze human biopsy samples to see if the sensors would also detect human cancers.

A similar sensor developed by the same team but administered intravenously is already being tested by Sunbird Bio in early-stage trials in humans for use in diagnosing liver cancer and fatty liver disease.

In parts of the world where there is limited access to CT scanning, this technology could offer a dramatic improvement in lung cancer screening, especially since the results can be obtained during a single visit, the researchers said.

“You come in and then you get an answer about whether you need a follow-up test or not, and we could get patients who have early lesions into the system so that they could get curative surgery or lifesaving medicines,” study leader Sangeeta Bhatia of the Massachusetts Institute of Technology said in a statement.

The risk of developing a dangerous immune response to stem cell transplantation may someday be modifiable by transplanting bacteria and viruses into the intestines, according to a new study.

So-called graft-versus-host disease (GVHD), in which the donated cells attack the patient’s body, now affect roughly half of stem-cell recipients.

Researchers studied stool samples obtained from 78 patients before and shortly after stem cell transplantation, measuring quantities of by products, or metabolites, produced by gut microbes.

Over the next two years, the risk of potentially deadly GVHD was lower in patients with higher amounts of immuno-defensive metabolites formed by Lachnospiraceae and Oscillospiraceae bacteria, and by viruses in the gut that live off those bacteria, according to a report published in Nature Cancer.

Patients with higher levels of these microbial metabolites had a higher chance of survival, fewer GVHD episodes, and fewer relapses, the researchers found.

Next, the researchers want to find out whether using fecal microbiota transplants to colonize the gut with specific populations of bacteria and viruses will help to prevent GVHD.

Initial experiments with mice have been successful, they said in a press statement.

This newsletter was edited by Bill Berkrot. Additional reporting by Shawana Alleyne-Morris.

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