istock
istock

Mitochondria May Be the Missing Link in Understanding Stress Response

istock
istock

Scientists have long looked to anatomy and neurology to understand and ameliorate stress responses in humans. Now, a pioneering study, recently published in Proceedings of the National Academy of Sciences, suggests that mitochondria—the tiny energy centers inside our cells, which convert food into ATP, the crucial molecule that stores the energy humans need to do pretty much everything—may play a more significant role in the stress responses of mammals than previously understood, and even in understanding psychiatric and neurologic diseases.

The study was headed by Douglas Wallace, director of the Center for Mitochondrial and Epigenomic Medicine at The Children’s Hospital of Philadelphia and a leading researcher in the genetics of mitochondria for 40 years. He is among the first to prove that defects in energy metabolism can cause disease.

Wallace and his team found that even slight changes in mitochondrial genes had a large effect on how mammals respond to stress in their environments. Wallace’s team bred mice with different genetic mutations to their mitochondrial DNA (mtDNA). “With these mutants in hand we could expose them to a mild environmental stress, such as 30 minutes in confinement,” Wallace tells mental_floss.

They then measured the neuroendocrine, inflammatory, metabolic, and gene transcription systems, which are the systems most effected by stress. “We found the changes in mitochondrian response had a markedly different response from normal mitochondria,” he says.

They mixed two normal, but different, mtDNAs in mice to prevent maternal inheritance of the mtDNA. This resulted in “hyperexcitable mice with severe learning and memory defects,” according to a press statement

Because humans and mice share a similar degree of variation in their mtDNA, Wallace suspects that the mouse results “might have a comparable effect” in human DNA.

While research is conflicting about how much stress increases risk of disease, psychiatrists have a term for the common physiological decline that happens when people are under continuous stress: allostatic load. “What is the connection between stress and declining bodily functions?" Wallace says. "The intermediate is the mitochondria.”

Wallace believes that the bioenergetics of mitochondrial function is the overlooked piece in understanding everything from psychiatric and neurologic diseases to aging, partly a result of the current “anatomical paradigm” in the scientific community, which focuses mostly on nuclear DNA, anatomy, and neurology. “What’s missed is the realization that mitochondria is much more important than just making ATP," he says. "It has a central regulatory role, because nothing in your body can go forward without energy. Mitochondria is the missing link between human behavior and human physiology.”

For example, he points out that neurons are “extraordinarily energetically demanding,” and that certain diseases could actually be a mitochondria disease. “All the tissues affected in common diseases also have the highest mitochondria energy demand, and it’s hard to see any anatomical difference between a normal and affected patient, because you can’t see energy,” he says. Wallace makes the case that aging could be chalked up to being “fundamentally the decline of the mitochondria’s ability to produce the energy to power the cells to keep us at optimum health.”

Wallace’s colleague Peter Burke has developed a new technique that makes it possible to analyze the energy of a single mitochondrion. “So now we can understand how subtle changes can have big effects on energy production and physiology,” Wallace says.

Wallace believes that further study could reveal ways to observe and even stop changes in the mitochondria before the obvious symptoms of disease have even begun—and that further research will show that changes in these “energetic genes” will be important in understanding diseases. But he’s concerned that the current scientific paradigm will be slow to embrace it, and thus fund it. He hopes it gets much more research, because he believes it could lead to a whole new generation of neuropsychiatric therapeutics: “This study will lead to a revolution in neuroscience," he says. "Whether the neuroscientists will accept it is another question."

nextArticle.image_alt|e
iStock
arrow
Health
Canine Flu is On the Rise: Here's What You Should Know
iStock
iStock

It's been eight years since the World Health Organization announced the end of the swine flu pandemic, and now the condition is back in the news for infecting a different type of host. As Live Science reports, the H1N1 virus is mixing with canine flu to create new strains that could potentially spread to people.

Dog flu has been around for a couple of decades, but the two main canine strains, H3N8 and H3N2, have never been contracted by humans. According to a new study published in mBio, some dogs in the Guangxi region of China were found carrying H1N1, the flu strain at the root of the swine flu outbreak. Researchers also discovered three entirely new flu strains that were a combination of H1N1 and regular dog flu viruses.

The unrecognized flu strains are the most troubling discovery. As the flu travels between species, it mingles with viruses that are already there, creating a level of genetic diversity that leaves our immune systems, which are best equipped to fight strains they've already been exposed to, vulnerable. The swine flu epidemic of 2009 started in a similar way, when H1N1 jumped from birds to pigs, and eventually to people.

But the new report isn't a reason to banish your pet to the doghouse next time she seems under the weather. The virus samples were collected from dogs in China between 2013 and 2015, and in the years since, zero humans have caught influenza from dogs (though dog flu has started spreading to cats). If the virus continues mutating to the point where it can infect humans, both the CDC and U.S. Department of Agriculture will take action. But for now, the CDC states that canine flu viruses "pose a low threat to people."

Canine flu may not be dangerous to humans yet, but it can still be stressful for dog owners if their pet comes down with a case. Ask your vet about getting your dog vaccinated, and if you see your dog coughing, sneezing, and acting less energetic than usual, make an appointment to get him checked out as soon as possible. If he does have the flu, he can be treated with plenty of rest and hydration.

[h/t Live Science]

nextArticle.image_alt|e
iStock
arrow
Live Smarter
3 Simple Ways to Stay Tick-Free This Summer
iStock
iStock

As the weather gets warmer, you no doubt want to don your favorite shorts and get out in the sunshine. Unfortunately, shorts season coincides with tick season, and we're in the midst of what one expert calls a "tick explosion."

Tick expert Thomas Mather of the University of Rhode Island told Boston 25 News that warm weather is going to lead to a particularly bad summer for ticks. The blood-sucking bugs aren't just annoying—they spread Lyme disease and several other serious illnesses, including a pathogen that can cause a sudden allergy to meat.

There are several precautions you should take to stay safe from ticks and the risks they carry during the high season, which usually lasts from April to September, though some ticks can stay active year-round as long as it's above freezing. While ticks usually live in grassy or wooded areas, you should be careful even if you live in the city, because pathogen-spreading ticks can still be hiding in urban parks.

Tick prevention begins when you get dressed. Wear long sleeves and pants, and if you're in a tick-prone area, tuck your pants into your socks to better protect your legs. Opt for light colored clothing, because it's easier to see bugs against a light color versus a dark one.

You'll want to invest in insect repellent, too, for both you and your pets. The CDC recommends treating your clothing (and tents, and any outdoor gear) with permethrin, an insecticide that you can apply to fabric that will last through several washes. Permethrin not only repels ticks, but kills them if they do manage to get onto your clothes, and you can buy socks and other clothing that come pre-treated with it. Insect repellents with DEET are also effective against ticks.

Since ticks are most likely to make their way onto your feet and ankles, make sure to treat your shoes and socks. And since your dog is more likely to get a tick than you are, make sure to get Fido a tick collar or some other kind of tick medication.

Most of all, you just need to stay vigilant. When you come inside from the outdoors, check your body for any ticks that may have latched on. Ticks can be as small as a poppyseed, so make sure to look closely, or ask someone else to check hard-to-see places like your back. And since they like moist areas, don’t forget to give your armpits and groin a careful look. If you do catch a tick, remove it as soon as you can with a pair of tweezers.

Best of luck out there.

SECTIONS

arrow
LIVE SMARTER
More from mental floss studios