Category Archives: Daily Dose

Potential treatment for severe influenza found in Omega-3 fatty acids

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shutterstock_129688976Omega-3 fatty acids, which have an important role in promoting healthy growth and development, have made headlines in recent years for, among other things, their possible cardiovascular benefits. Found in high levels in fish oil, these fatty acids are the most consumed non-vitamin or non-mineral supplement in the US. Now, researchers have discovered another potential use for these fat building blocks: using them as a treatment for flu.

In a study published today in Cell, a modified omega-3 fatty acid known as protectin D1 was found to markedly increase the chances of survival in mice with infected with various strains of influenza, including the H1N1 strain behind the 2009 ‘swine flu’ epidemic.

“The authors show for the first time that [protectin D1] actually disrupts replication of influenza,” says Charles Serhan, an anesthesiologist at Brigham and Women’s Hospital in Boston. “It provides a natural template for new therapeutic development.”

When given microgram doses of protectin D1 intravenously 12 hours before and immediately after infection with a strain of influenza A, three out of eight treated animals survived past a two-week end point; by comparison, all seven control counterparts died within eight days. Mice infected with the 2009 strain of H1N1 swine flu fared even better when treated in this manner—all six survived, compared with only two out of six in the group that received only a saline solution.

Protectin D1 given two days post-infection appeared nearly as effective in preventing death in mice as Peramivir, an intravenous anti-viral drug marketed by BioCryst Pharmaceuticals of Durham, North Carolina. Approved in Japan and Korea for treating severe flu, Peramivir did not move past phase III clinical trials in the US for efficacy, but was subject to an emergency FDA authorization in 2009 as a treatment for H1N1 swine flu.

Remarkably, while less than half of treated animals survived past two weeks on either therapeutic alone after infection with influenza A, none died after receiving protectin D1 and Peramivir in conjunction.

In a petri dish model using human lung cells, protectin D1 appeared to reduce the virulence of influenza by blocking the export of viral mRNA from a cell’s nucleus, according to the new study. This is reflected in a massive decrease in the infection rate of cells.

Derived from omega-3 fatty acids, protectin D1 is one of a family of similar fat molecules with apparent antiinflammatory and antibiotic properties. Naturally produced, these compounds are thought to play a protective effect in the lung, brain and other organs. This study is the first to demonstrate anti-viral qualities for these molecules, with protectin D1 showing the greatest efficacy.

“I see this as opening a whole new avenue of research,” says Serhan, who was the first to characterize protectin D1 in 2007. He notes that this could represent a new class of antivirals that work by both reducing excessive inflammation and by disarming replication of the virus. The risk for side effects could be low as well since “it’s a natural mechanism,” says Serhan.

Many questions remain as to protecin D1’s therapeutic potential in humans, as well as if these omega-3 fatty acid-derived molecules could treat other types of viral infections. Future clinical trials and research are needed to prove efficacy and safety, says Serhan. For now, he recommends not over-doing it with fish oil supplements, until scientists know more about the underlying mechanisms. “You don’t want to be deficient in [omega-3], but I wouldn’t go the other direction. There could be unwanted side effects.”

Image: Shutterstock

Researchers promise universal flu vaccine — yet again

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3D_Influenza_black_no_key_full_sml.jpgJudging by today’s headlines, one could be fooled into thinking that the ever-elusive universal flu vaccine could be just around the corner.

In the latest study, researchers from the University of Oxford’s Jenner Institute exposed 22 people to the H3N2 flu virus, half of whom were vaccinated with an experimental universal flu shot. According to the press accounts, they found that fewer people in the immunized group came down with the illness.

How many fewer people? What degree of protection does this new vaccine offer? Unfortunately, not one of the dozens of news articles includes any details.

Perhaps these outlets simply rushed to press? I rang up Sarah Gilbert, the lead investigator of the study, to find out the straight skinny.

“I can’t tell you that I’m afraid because the paper is submitted for publication and that needs to come out before we can go into any detail,” Gilbert told me.

So it seems this is just another incident of the media jumping on the possibility of a universal flu shot — something that even we at Nature Medicine have been guilty of. But in our defense, at least we’ve waited for the research to be peer-reviewed and published, and sometimes even publishing the research studies ourselves.

So, until the Oxford team makes its data public, we just do not know how well this new vaccine stacks up to the competition. And we in the media need to exhibit editorial constraint before rushing through stories that might falsely raise the hopes of the millions who suffer annually from this winter nuisance.

For added perspective on long-lasting flu shots, read this commentary by Gary Nabel and Anthoni Fauci, two leading vaccine researchers at the US National Institute of Allergy and Infectious Diseases, from the December 2010 issue of the journal.

Image: CDC