By Debbie Bunch
October 7, 2024
Viruses That Linger Could be Behind Chronic Lung Conditions
A study conducted in mice by investigators from Washington University School of Medicine in St. Louis suggests eliminating immune cells in the lungs where respiratory viruses hide out after symptoms of the illness are gone may hold promise for preventing or treating chronic lung diseases like asthma and COPD.
The researchers reached that conclusion after developing a unique system consisting of the Sendai virus, which is a respiratory virus in mice similar to the human parainfluenza virus, along with fluorescent markers of infection that allowed them to observe signs of the virus throughout the infection.
While the mice recovered after about two weeks, viral RNA and protein were still detectable in their lungs several weeks later, hidden away in immune cells where they increased inflammation. The finding was surprising, because researchers have been looking for viral products in epithelial cells, since that’s where viruses primary replicate.
By week seven following the infection, and long after the mice had recovered, their lungs showed signs of inflammation in the air sacs and blood vessels, an abnormal development of lung cells, and excess immune tissue, all signs of chronic inflammatory lung damage that may promote the development of chronic lung diseases.
Once the infected immune cells were eliminated, signs of the damage diminished.
“We use a perfectly matched virus-host pairing to prove that a common respiratory virus can be maintained in immunocompetent hosts for way longer than the acute phase of the infection, and that this viral persistence can result in chronic lung conditions,” said study author Araújo Castro, PhD. “Probably the long-term health effects we see in people who are supposed to be recovered from an acute infection are actually due to persistence of virus in their lungs.”
Fellow author Carolina B. López, PhD, pointed out the possible implications for kids with asthma. “Right now, children who have been hospitalized for a respiratory infection such as RSV are sent home once their symptoms resolve,” she said. “To reduce the risk that these children will go on to develop asthma, maybe in the future we will be able to check if all of the virus is truly gone from the lung, and eliminate all lingering virus, before we send them home.”
The study was published by Nature Microbiology. Read Press Release Read Abstract
Breath Test Holds Promise for Diagnosing LRTIs in the ICU
Researchers from Johns Hopkins have developed a new noninvasive test that can diagnose lower respiratory tract infections (LRTIs) in critically ill patients using a breath sample.
The study was driven by the need for a quicker and easier test for LRTIs, which today are diagnosed based on time-consuming microbiological methods like culture or molecular techniques like nucleic acid amplification testing, which requires pathogen materials to be present within the samples, thus making it difficult to distinguish between infection and colonization.
The new breath sampling system, called BreathBiomics, measures host response factors such as proteases, which are often dysregulated during LRTIs, instead.
Breath samples were collected from intubated patients on mechanical ventilation and healthy volunteers, with results divided into an LRTI group and a non-LRTI group. An in vitro assay, developed by designing a specific substrate sensor for human neutrophil elastase (HNE), was used to analyze the samples. Among the findings –
- The LRTI group demonstrated a significant mean differential, showing a 9.8-fold elevation in measured HNE activity compared with the non-LRTI group and a 9.2-fold elevation compared with healthy volunteers.
- The in vitro assay’s diagnostic potential was assessed by constructing a receiver operating characteristic curve, resulting in an area under the curve of 0.987.
- Using an optimal threshold for HNE at 0.2 pM, the sensitivity was determined to be 1.0 and the specificity to be 0.867.
- Further correlation analysis revealed a strong positive relationship between the measured HNE activity and the protein concentration in the breath samples.
“Our study provides strong evidence supporting the correlation between HNE activity and LRTIs, demonstrating significant diagnostic promise,” concluded the authors. “We anticipate that our approach could serve as a valuable screening tool for LRTIs, particularly in intubated patients within critical care settings.”
The study was published by PNAS Nexus. Read Article Read Full Paper
Voice Quality May Predict COPD Exacerbations
Could changes in a person’s voice predict the onset of an acute exacerbation of COPD?
Researchers from The Netherlands who analyzed speech changes in COPD patients believe they can.
The pilot study, which was presented during the recent European Respiratory Society meeting, was conducted among patients taking part in a prospective cohort study designed to collect voice samples from COPD patients on a daily basis for 12 weeks. Eleven patients completed the voice screenings, and among that group, 16 exacerbations were noted, six of which were treated.
Significant differences were seen between the voice recordings made at baseline, the onset of an exacerbation, and at peak symptoms, with voices becoming more pitched and breathy or hoarse during the early stages of the exacerbation.
The authors believe voice changes could be incorporated into future mobile health applications to help detect COPD exacerbations at a point when they can still be treated at home. Read Article Read Abstract
