Most people with spinal cord injury are paralyzed from the injury site down, even when the cord isn’t completely severed. Why don’t the spared portions of the spinal cord keep working, allowing at least some movement? A new study just published online by Cell provides insight into why these nerve pathways remain quiet. Most intriguingly, it shows that injection with a small-molecule compound can revive these circuits in paralyzed mice — and get them walking again.
“We saw 80 percent of mice treated with this compound recover their stepping ability,” says Zhigang He, PhD, of Boston Children’s Hospital’s F.M. Kirby Neurobiology Center, the study’s senior investigator. “For this fairly severe type of spinal cord injury, this is the most significant functional recovery we know of.” …
Animal cloning, the creation of a genetically identical copy of an individual organism, holds promise for many different reasons, including its use to conserve endangered species and to improve our understanding of developmental biology, which could eventually help us prevent or reverse developmental disorders from the get-go. Although more than 20 species of animals have been cloned so far, cloning efficiency, or the percent of successful live births, has remained universally low and economically out of reach for most practical applications.
But now, researchers at Boston Children’s Hospital have reported a new cloning technique that has yielded the highest efficiency ever reported in mouse cloning, capable of producing 13 to 16 times more mouse pups than previous methods. The findings were reported in Cell Stem Cell.
Second in a two-part series on transplant tolerance. (See part one.)
Our immune system has two major kinds of T cells. T helper cells, also known as effector T cells, tend to rev up our immune responses, while T regulatory cells tend to suppress or downregulate them. Last week we reported that bolstering populations of T regulatory cells might help people tolerate organ transplants better. A new study turned its focus to T helper cells, and found that an imbalance of these cells causes an exaggerated immune response that may also contribute to transplant rejection.
The study also showed, in mice and in human cells in a dish, that the immune imbalance can be potentially reversed pharmacologically. Findings were published yesterday in the Journal of Clinical Investigation. …
A new discovery about the spatial orientation and physical interactions of our genes provides a promising step forward in our ability to design custom antibodies. This, in turn, could revolutionize the fields of vaccine development and infection control.
Recent years of research by Alt and others in the field of molecular biology have revealed that it’s not just our genes themselves that determine health and disease states. It’s also the three-dimensional arrangement of our genes that plays a role in keeping genetic harmony. Failure of these structures may trigger genetic mutations or genome rearrangements leading to catastrophe.
The importance of genetic loops
Crammed inside the nucleus, chromatin, the chains of DNA and proteins that make up our chromosomes, is arranged in extensive loop arrangements. These loop configurations physically confine segments of genes that ought to work together in a close proximity to one another, increasingly their ability to work in tandem.
“All the genes contained inside one loop have a greater than random chance of coming together,” says Suvi Jain, PhD, a postdoctoral researcher in Alt’s lab and a co-first author on the study.
Meanwhile, genes that ought to stay apart remain blocked from reaching each other, held physically apart inside our chromosomes by the loop structures of our chromatin.
But while many chromatin loops are hardwired into certain formations throughout all our cells, it turns out that some types of cells, such as certain immune cells, are more prone to re-arrangement of these loops. …
For decades, cardiac researcher James McCully, PhD, has been spellbound by the idea of using mitochondria, the “batteries” of the body’s cells, as a therapy to boost heart function. Finally, a clinical trial at Boston Children’s Hospital is bringing his vision — a therapy called mitochondrial transplantation — to life.
Mitochondria, small structures inside all of our cells, synthesize the essential energy that our cells need to function. In the field of cardiac surgery, a well-known condition called ischemia often damages mitochondria and its mitochondrial DNA inside the heart’s muscle cells, causing the heart to weaken and pump blood less efficiently. Ischemia, a condition of reduced or restricted blood flow, can be caused by congenital heart defects, coronary artery disease and cardiac arrest.
For the smallest and most vulnerable patients who are born with severe heart defects, a heart-lung bypass machine called extracorporeal membrane oxygenation (ECMO) can help restore blood flow and oxygenation to the heart. But even after blood flow has returned, the mitochondria and their DNA remain damaged.
“In the very young and the very old, especially, their hearts are not able to bounce back,” says McCully.
Ischemia can be fatal for the tiniest patients
After cardiac arrest, for instance, a child’s mortality rate jumps to above 40 percent because of ischemia’s effects on mitochondria. If a child’s heart is too weak to function without the support of ECMO, his or her risk of dying increases each additional day spent connected to the machine.
But what if healthy mitochondria could come to the rescue and replace the damaged ones? …
First in a two-part series on transplant tolerance. Read part two.
Although organ transplant recipients take drugs to suppress the inflammatory immune response, almost all eventually lose their transplant. A new approach, perhaps added to standard immunosuppressant treatment, could greatly enhance people’s long-term transplant tolerance, report researchers at Boston Children’s Hospital.
The approach, which has only been tested in mice as of yet, works by maintaining a population of T cells that naturally temper immune responses. It does so by turning on a gene called DEPTOR, which itself acts as a genetic regulator. In a study published July 3 in the American Journal of Transplantation, boosting DEPTOR in T cells enabled heart transplants to survive in mice much longer than usual. …
Tissue expanders — small balloons that can be filled with saline solution or other fluids to grow skin — have long been used in plastic surgery, most commonly breast reconstruction. They’re based on the simple idea that the surrounding skin will stretch as the device expands over time. That extra skin can then help repair injuries or congenital anomalies or accommodate implants.
Midaortic syndrome occurs when the middle section of the aorta is narrowed and typically affects children and young adults. It can cause severe hypertension and can be life-threatening if left untreated. The surgical approach to this condition would be to replace the damaged portion of the aorta with nearby healthy blood vessels. However, this usually isn’t possible because these vessels tend to be too short to adequately fill in. …
Precision medicine is often equated with high-tech, exquisitely targeted, million-dollar drug treatments. But at Precision Medicine 2018, hosted by Harvard Medical School’s Department of Biomedical Informatics (DBMI) this week, many of the speakers and panelists were more concerned about improving health for everyone and making better use of what we already have: data.
“We’re not going to make major changes in 21st century medicine without embracing data-driven approaches,” said HMS dean George Q. Daley in his opening remarks. …
Kaylee Goodwin, 29, has struggled her whole life to control her blood levels of “phe” — the amino acid known as phenylalanine. “I was told that if my levels were controlled, I would be able to think more clearly and feel better overall,” she says.
Goodwin was born with phenylketonuria (PKU), a genetic metabolic disorder affecting roughly 1 in 16,000 newborns. Her body can’t break down phe because of a genetic mutation disabling the necessary enzyme, phenylalanine hydroxylase (PAH).
If left untreated, phe accumulates in the brain, causing intellectual disability and seizures. But starting in the early 1960s, newborn screening programs have been able to test for PKU. Goodwin tested positive and was prescribed a special phe-free diet by Harvey Levy, MD, at Boston Children’s Hospital.
Through the diet, Goodwin has dodged serious brain damage and was able to attend college and start a career as a dancer and actress. But because phe is in nearly all naturally occurring proteins, she couldn’t eat meat, eggs, dairy products, legumes, most grains and many fruits and vegetables. Instead, she had to consume a foul-tasting amino acid formula.
“I spent my entire life carrying special foods and medical formula around with me, and weighing and measuring foods,” she says. …
Research tells us that the “good” bacteria that inhabit our intestines help to regulate our metabolism. A new study in fruit flies shows one of the ways in which these commensal microbes keep us metabolically fit.
The findings, published today in Cell Metabolism, suggest that innate immune pathways, our first line of defense against bacterial infection, have a side job that’s equally important.
The intestine’s digestive cells use an innate immune pathway to respond to harmful bacteria by producing antimicrobial peptides. But other intestinal cells, enteroendocrine cells, use the same pathway, known as IMD, to respond to “good” bacteria — by fine-tuning body metabolism to diet and intestinal conditions.
“What’s most interesting to me is that some innate immune pathways aren’t just for innate immunity,” says Paula Watnick, MD, PhD, of the Division of Infectious Diseases at Boston Children’s Hospital. “Innate immune pathways are also listening to the ‘good’ bacteria – and responding metabolically.” …