Heart muscles, like skeletal muscles, are made up of two major types of muscle fibers: fast twitch and slow twitch. Fast twitch fibers move quickly but tire easily, while slow twitch fibers move slower but last longer. Both serve important functions in different circumstances. For example, marathon runners tend to have a predominance of slow twitch fibers in their skeletal muscle; the opposite is true for sprinters.
Existing asthma medications work by suppressing inflammatory signaling by immune cells or by dilating constricted airways. Over time, though, these drugs’ benefits can wane. New research supports a surprising new tactic for controlling asthma: targeting sensory nerve endings in the lungs with a selective drug.
Our lungs are known to contain specialized sensory neurons known as nociceptors that connect to the brainstem. Best known for causing the perception of pain, nocieptors also trigger the cough reflex in the lungs when they detect potential harms like dust particles, chemical irritants or allergens. Nociceptor nerve endings are known to be more plentiful and more readily activated in people with asthma. Now it’s also clear that they help drive allergic inflammation.
A report this April rocked the scientific world: scientists in China reported editing the genomes of human embryos using CRISPR/Cas9 technology. It was a limited success: of 86 embryos injected with CRISPR/Cas9, only 71 survived and only 4 had their target gene successfully edited. The edits didn’t take in every cell, creating a mosaic pattern, and worse, unwanted DNA mutations were introduced.
“Their study should give pause to any practitioner who thinks the technology is ready for testing to eradicate disease genes during [in vitro fertilization],” George Q. Daley, MD, PhD, director of the Stem Cell Transplantation Program at Boston Children’s Hospital, told The New York Times. “This is an unsafe procedure and should not be practiced at this time, and perhaps never.”
As Daley detailed last week in his excellent presentation at Harvard Medical School’s Talks@12 series, the report reignited an ethical debate around tampering with life that’s hummed around genetic and stem cell research for decades. What the Chinese report adds is the theoretical capability of not just changing your genetic makeup, but changing the DNA you pass on to your children.
Sometimes it’s just as important to rule a gene out as the cause of a condition as it is to rule it in, especially for complex, multi-gene traits like obesity. In a report published yesterday by Nature Genetics, a gene once thought to be the single greatest genetic influence on human obesity actually has nothing to do with body weight.
The study, led by researchers at Harvard Medical School (HMS) and Boston Children’s Hospital, also provides the first effective ways to analyze complicated parts of the genome.
The gene in question, AMY1, encodes an enzyme in our saliva that helps convert starch into sugar. “There’s been some speculation that because this enzyme helps get nutrients out of our food, it could be linked to obesity,” said Christina Usher, a graduate student at HMS and first author on the paper.
What’s complicated is that people can have anywhere from 2 to 14 copies of AMY1—or more. In 2014, an unrelated international group reported in Nature Genetics that people with fewer than four copies of AMY1 had a roughly eight times greater risk for obesity than people with more than nine copies of the gene. AMY1 therefore appeared to be protective.
Non-narcotic treatments for chronic pain that work well in people, not just mice, are sorely needed. Drawing from human pain genetics, an international team demonstrates a way to break the cycle of pain hypersensitivity without the development of addiction, tolerance or side effects. Their findings were published online today in the journal Neuron.
Second in a two-part series on metabolic liver disease. Read part 1.
According to the American Liver Foundation, about 1 in 10 Americans have some form of liver disease. One rare, under-recognized disorder, lysosomal acid lipase (LAL) deficiency, can fly under the radar until it becomes life-threatening, often requiring a liver transplant. LAL deficiency currently has no specific treatment, but that may change thanks to combined expertise in genetics, metabolism and hepatology.
“LAL deficiency is currently under-diagnosed,” Neilan says. “We think the disease is more common than doctors have thought and now, with a treatment in trial, it is of greater importance to identify those patients so they may have better outcomes.”
First in a two-part series on metabolic liver disease. Read part 2.
In the clinical world, Boston Children’s Hospital surgeon Khashayar Vakili, MD, specializes in liver, kidney and intestinal transplant surgeries, while in the lab he is doing work which, for some patients, could eliminate the need for a transplant surgeon altogether.
Dhaka, Bangladesh, is a megacity, one of the world’s fastest growing. By 2025, the U.N. predicts, Dhaka will be home to more than 20 million people as rural migrants swell its population. Many residents live in extreme poverty, crowded into dense, hot, chaotic slums with open sewers and corrugated housing.
While traditional global health programs have focused on curbing infectious disease, low-resource settings like Dhaka are also coming to be seen as “living laboratories” for investigating how adversity affects children’s brain development. Last year, the Bill & Melinda Gates Foundation awarded a two-year, $2.5 million grant to Charles Nelson, PhD, to bring the first fully equipped neuroimaging facility to Bangladesh.
If you have children present, you might want to click out of this post. But if you want to understand motivation, you’ll want to know about the sexual behavior of fruit flies.
In the brain, motivational states are nature’s way of matching our behaviors to our needs and priorities. But motivation can go awry, and dysfunction of the brain’s motivation machinery may well underlie addiction and mood disorders, says Michael Crickmore, PhD, a researcher in the F.M. Kirby Neurobiology Center. “Basically, every behavior or mood disorder is a disorder of motivation,” he says.
It’s already known that brain cells that communicate via the chemical dopamine are important in motivation—and are also implicated in ADHD, depression, schizophrenia and addiction. But what exactly are these cells up to, and who are they talking to? That’s where fruit flies come in.
“We study motivation in a simple system that we can bash very hard,” says Crickmore.
Can a robotic talking bear have therapeutic value? “The Bear,” part of a New York Times video series called Robotica, offers a glimpse of Huggable’s potential when Beatrice Lipp, a child with a chronic medical condition, visits the hospital, nervous about what’s to come.
“We want to offer kids one more way of helping them to feel OK where they are in what’s otherwise a really stressful experience,” explains Dierdre Logan, PhD, director of Psychological Services for Pain Medicine at Boston Children’s Hospital.
Huggable, a creation of the MIT Media Lab’s Personal Robots Group and the Boston Children’s Simulator Program, comes into Beatrice’s room to chat, play games like “I Spy” and tell jokes. The session is recorded on video, and a bracelet called a Q Sensor collects Beatrice’s physiologic data–changes in skin conductance, temperature and motion that may indicate distress. Researchers at Northeastern University are analyzing these data to gauge the robot’s effect. Eventually, Huggable will be able to react to the data and respond accordingly—offering relaxation exercises and guided imagery, for example, if a child remains anxious.
Currently, Huggable is voiced by Child Life staff, but the ultimate goal is for it to work autonomously. Beatrice is part of a 90-child study comparing Huggable, an ordinary teddy bear and a tablet Huggable image.
I admit: My immediate thought on seeing Huggable was that kids would immediately see him (her?) as a fake, but the bear’s robotic nature doesn’t seem to faze them. As Logan says in the video:
I think there’s a way of connecting with kids that’s different than what grownups have to offer. They have incredible imaginations. And they can really suspend disbelief. There can be a true relationship that develops between Huggable and a patient.