HKU breakthrough in fight against bird fluLocal | Mary Ann Benitez 17 Mar 2016
University of Hong Kong scientists hope an experimental drug used for acute respiratory distress syndrome could better treat the dreaded bird flu H5N1 virus.
The School of Public Health first discovered that H5N1 causes severe pneumonia by impairing proteins called sodium and chloride transporter molecules in the lungs that help draw fluid out of the organs.
With the discovery of the mechanism of infection, the scientists have begun laboratory testing an experimental treatment for H5N1 using mesenchymal stromal cells.
The bone marrow-derived stromal cells are already undergoing clinical trials for sepsis and acute respiratory distress syndrome in the United States.
But no one has tested whether the same cells also could be effective against viral respiratory infections such as flu.
The treatment strategy could also be used against other bird flu viruses, H7N9 and H9N2, as well as MERS and SARS coronaviruses, said the lead researcher, the school's assistant professor Michael Chan Chi-wai.
Using laboratory mice, the 14-member team found that H5N1 infection impaired fluid clearance in the lungs' alveoli tiny sacs that allow oxygen and carbon dioxide to move between the lungs and bloodstream more than did seasonal virus.
The infected cells release "soluble factors" that impair the alveolar sodium and chloride transporters, the team said.
"Mesenchymal stromal cells prevented or reduced this effect in vitro and in vivo in H5N1-infected mice. These cells provide a potentially effective treatment for acute lung injury in severe influenza," the report concluded.
Chan said: "We showed that when mice are infected with H5N1, it will inhibit the proteins and the mice developed edemas, lung infection and died. If we treat mice with mesenchymal stromal cells so that activity of sodium and chloride transporter proteins return back to normal, it resolved the edemas."
He said the cells come from bone marrow and could be isolated from the umbilical cord and fatty tissues.
School director Malik Peiris said: "These findings may also be relevant to other viruses that may cause severe viral pneumonia by similar mechanisms, such as SARS and MERS coronaviruses and other avian influenza viruses such as H7N9 and H9N2."
The team, which includes scientists from the University of California, San Francisco, and St Jude Children's Research Hospital in Memphis, will conduct more detailed animal studies before proceeding to clinical trials.
The groundbreaking findings were published in the latest issue of the Proceedings of the National Academy of Sciences of the United States of America.