How fish farming might spawn disease, ‘brain pacemakers’ might reduce dementia and macrophages might help the heart keep the beat

How Fish Farming Might Bait Disease

(The Scientist, 4/19/17, Claire Asher)

When we sit down for a meal of salmon, chances are it didn’t come from the wild but from the farm. That, unfortunately, may not be a good thing. Fish farming is one of the fastest growing food production sectors in the world, but infections caused by bacteria, viruses, and parasites cost the industry billions of dollars in worldwide. A project led by researchers from Norway found that Atlantic salmon (Salmo salar) infected with salmon lice (Lepeophtheirus salmonis) derived from two Norwegian fish farms suffered more-severe symptoms than those infected with lice from wild salmon, suggesting that pathogens are becoming more virulent in farm-raised fish. Nor is natural selection for increased virulence is not limited to salmon lice. A Finnish study reported signs of increasing virulence in the fish pathogen Flavobacterium columnare over time.

Immune Cells Got the Beat

(Science, 4/20/17, Mitch Leslie)

Our immune cells main job is protecting us against infection. But it turns out they also might contribute to heart health. A new study published this week in Cell by scientists from Harvard Medical School found discovered that mice who lacked macrophages, a type of immune best known for “consuming” cellular debris, microbes and cancer cells, also had hearts with abnormal electrical rhythms. Moreover, by growing macrophages and heart cells in a dish, they found that macrophages were common in atrioventricular nodes that relay impulses to ventricles, the heart’s pumping chambers, and allows them to contract. These observations were also made in a mouse’s beating heart.

Pacemakers for the Brain?

(New York Times, 4/20/17, Benedict Carey)

Well-timed pulses from electrodes implanted in the brain can enhance memory in some people, scientists reported on Thursday, in the most rigorous demonstration to date of how a pacemaker-like approach might help reduce symptoms of dementia, head injuries and other conditions. The report is the result of decades of work decoding brain signals, helped along in recent years by large Department of Defense grants intended to develop novel treatments for people with traumatic brain injuries, a signature wound of the Iraq and Afghanistan wars. The research, led by a team at the University of Pennsylvania, is published in the journal Current Biology.

—Compiled by Senior Scientific Writer Regina McEnery