A new study suggests that potentially deadly infections in cystic fibrosis (CF) patients might be destroyed by dousing them with a mixture of mostly soybean oil and water. The so-called "nanoemulsion" has so far only been tested in bacteria in the lab, but the researchers say they will now test it in animals and, if successful, conduct clinical trials in people with CF.
"The nanoemulsion inhibited the growth of all 150 [bacterial] strains tested," says John LiPuma, a pediatrician at the University of Michigan (UM) in Ann Arbor and coauthor of the study published recently in the journal Antimicrobial Agents and Chemotherapy. "It was very effective in vitro."
Cystic fibrosis affects 30,000 children and adults in the U.S. and 70,000 people worldwide, according to the Cystic Fibrosis Foundation, a nonprofit based in Bethesda, Md. Patients with the disorder produce excessive amounts of thick and sticky mucus that obstructs the airways, leading to potentially fatal lung infections. There is no cure for CF and the median age for survival is 37 years of age, though new treatments have helped many people live into their 50s.
In this study, the researchers focused on 150 strains of bacteria known to cause some of the most difficult-to-treat infections in cystic fibrosis patients. Some of these bugs, which do not usually cause infections in healthy people, are resistant to several or even all antibiotics. The researchers took the bacteria, put them in test tubes, and exposed them to the nanoemulsion, a milky liquid made of tiny droplets of soybean oil, water, and surfactant (a chemical that keeps the oil and water droplets from separating into two layers like oil and vinegar in salad dressing).
The nanoemulsion wiped out all 150 bacterial strains tested, and it even worked when the bacteria were washed in sputum (saliva mixed with mucus or pus) taken from the lungs of cystic fibrosis patients. (According to LiPuma, bacteria tend to hide in sputum, making it harder kill them with antibiotics.)
How can such an apparently innocuous oil-and-water preparation be such a ruthless bacteria killer? "These droplets are very high energy," says study co-author James Baker, head of the Michigan Nanotechnology Institute for Medicine and Biological Sciences. "When [one of the oil droplets] sees a bacterial or viral membrane, it fuses with it and releases energy that physically disrupts [and] literally blows up the bacteria or viruses." Fortunately, the nanoemulsion does not have the same effect on human or animal cells, which are glued together by a protective protein matrix, Baker adds.
LiPuma says the next step is to test its safety in animals and then people so it might be harnessed to fight lung infections in cystic fibrosis patients. The ultimate goal is to deliver the nanoemulsion through a device called a nebulizer that delivers medicine to the lungs in the form of a mist if doing so proves to be safe and effective.
The company that makes the nanoemulsion, NanoBio Corporation in Ann Arbor, Mich., recently began tests to determine whether the nanoemulsion can be safely administered to dogs using nebulizers. (Baker, who has a patent on the nanoemulsion, is chairman of the board at NanoBio. LiPuma says he has no financial ties to the company).