Viruses that infect bacteria in digestive tract may play role in PAH: Study
Findings highlight potential of gut virus-targeted therapies
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People with pulmonary arterial hypertension (PAH) have less diversity among the viruses that infect bacteria in their digestive tracts, according to a new study.
These findings add to a growing body of research suggesting that the gut microbiome — the community of bacteria, viruses, and other microscopic organisms that make their home in human intestines — may play a role in PAH.
“These data extend microbiome research in pulmonary hypertension beyond bacteria, identifying viruses as key modulators of [the microbiome] … and highlighting the potential of [gut virus]-targeted strategies as novel therapeutic avenues,” researchers wrote.
The study, “Alterations in the fecal virome and bacteriome–virome interplay in IPAH,” was published in Respiratory Research.
Gut viruses showed associations with markers of IPAH severity
PAH is marked by abnormally high resistance in the vessels that carry blood from the heart through the lungs, which puts strain on the heart. In the most common form, known as idiopathic PAH or IPAH, the underlying causes of the disease are not clear.
Several previous studies have suggested that abnormalities in gut bacteria may be involved in PAH. But bacteria are not the only tiny organisms that live in the human digestive system — alongside the bacteria are whole communities of viruses, which routinely infect gut bacteria. These viruses may kill some species of gut bacteria; they also can participate in sharing genes between different bacterial cells.
Although many previous studies have looked at gut bacteria in PAH, these gut viruses have not been studied in-depth. To address this gap in knowledge, a team of scientists in China conducted in-depth profiling of both gut bacteria and gut viruses using fecal samples from 28 people with IPAH. Samples from 30 people without IPAH who were matched according to age and sex were also analyzed for comparison.
Collectively, these findings suggested that viruses may participate in gut ecological regulation by targeting specific bacterial hosts. Virus-bacterium interactions may jointly influence the development and progression of IPAH.
Results showed that the IPAH patients had marked abnormalities in the types of viruses that were living in their guts. In particular, the researchers noted that IPAH patients generally had less diversity of gut viruses. The changes in gut viruses were also accompanied by differences in gut bacteria — including bacteria that are known to make signaling molecules that regulate IPAH-associated biological processes such as inflammation.
“Collectively, these findings suggested that viruses may participate in gut ecological regulation by targeting specific bacterial hosts,” the researchers wrote. “Virus-bacterium interactions may jointly influence the development and progression of IPAH.”
In further analyses, the researchers found dozens of gut viruses that showed significant associations with markers of IPAH severity. For example, IPAH patients with higher levels of a type of gut virus called Uroviricota tended to have lower mean pulmonary arterial pressure, a measurement of blood pressure in the lungs’ vessels. This association indicated that Uroviricota viruses in the gut may have a protective effect, reducing the severity of IPAH, the researchers said.
The scientists stressed that this study was limited to a small number of patients. Also, it is not possible to say whether the identified changes are causes or consequences of disease development. As such, more studies are warranted to further explore the role of the imbalance in the gut viral population in PAH disease processes, the researchers wrote
Janet Hoffman
My son passed away in 2009 2007 he was 17 years old all of a sudden, but diagnosed with pulmonary hypertension within the next four months he had a double lung transplant had lots of problems that go along with a transplant and initially subdued to chronic rejection in passed away in 2009 and biopsy did shown that he had a pulmonary occlusive disease. My question to you as when he was five years old he got very sick. He had a severe virus flu symptoms. That was very sick within a short period of time after the flu he ended up having a emergency appendicitis surgery.. was never really sick after that besides just mild flus and colds until he was 17 years old and had his first of symptom due to pulmonary hypertension. It came on fast and sudden.. do you think that the flu that he had when he was five years old that hospitalized him would have anything to do with him contracting pulmonary hypertension/pulmonary inclusive disease. I have always felt that when he got the flu at five years old and it was so severe that it may have something to do with his diagnosis later on in his teens. We were told by Doctors that they don’t know how he contracted the disease. They tested for everything and and all came back negative do you think this horrible virus that he had in five years old had something to do with his outcome?
Douglas Brooks
Thank you for continuing to help make information about possible causes of PAH more widely available, which will ultimately help people avoid falling prey to this tragic condition.