Author: Nancy Fliesler

Probing the brain’s earliest development, with a detour into rare childhood cancers

In early brain development there is an increase in ribosomes, contained in these nucleoli
Nucleoli, the structures in the cell nucleus that manufacture ribosomes, are enlarged in very early brain development, indicating an increase in ribosome production. Here, a 3D reconstruction of individual nucleoli. (Kevin Chau, Boston Children’s Hospital)

In our early days as embryos, before we had brains, we had a neural fold, bathed in amniotic fluid. Sometime in the early-to-mid first trimester, the fold closed to form a tube, capturing some of the fluid inside as cerebrospinal fluid. Only then did our brains begin to form.

In 2015, a team led by Maria Lehtinen, PhD, Kevin Chau, PhD and Hanno Steen, PhD, at Boston Children’s Hospital, showed that the profile of proteins in the fluid changes during this time. They further showed that these proteins “talk” to the neural stem cells that form the brain.

In new research just published in the online journal eLife, Lehtinen and Chau shed more light on this little-known early stage of brain development.

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Elusive epilepsy mutations begin to yield up their secrets

mosaic epilepsy mutations concept
Fawn Gracey illustration

Anti-seizure drugs don’t work in about a third of people with epilepsy. But for people with focal epilepsy, whose seizures originate in a discrete area of the brain, surgery is sometimes an option. The diseased brain tissue that’s removed also offers a rare opportunity to discover epilepsy-related genes.

Many mutations causing epilepsy have been discovered by testing DNA taken from the blood. But it’s becoming clear that not all epilepsy mutations show up on blood tests. So-called somatic mutations can arise directly in tissues like the brain during early prenatal development. Even within the brain, these mutations may affect only a fraction of the cells — those descended from the original mutated cell. This can create a “mosaic” pattern, with affected and unaffected cells sometimes intermingling.

One of the first such mutations to be described, by Ann Poduri, MD, MPH, and colleagues at Boston Children’s Hospital in 2012, was in Dante, a young boy who was having relentless daily seizures. The entire right side of Dante’s brain was malformed and enlarged, and he underwent a drastic operation, hemispherectomy, to remove it. Only later, studying brain samples from Dante and similar children, did Poduri find the genetic cause: a mutation in the gene AKT3. It affected only about a third of Dante’s brain cells. 

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How well do gluten-free diets eliminate gluten, and is home gluten testing a good thing?

gluten testing could help predict intestinal health in patients with celiac disease

For patients with celiac disease, following a gluten-free diet is complicated and often challenging.

“Our patients are navigating a gluten-free diet without any feedback to guide them,” says Jocelyn Silvester, MD, PhD, director of research at the Celiac Disease Program at Boston Children’s Hospital. “Symptoms are not a reliable indicator of gluten exposure. Many patients may not have any symptoms at all.”

For clinicians, assessing how well patients are doing on a gluten-free diet can be equally difficult. “There are no good measures of how well the gluten-free-diet is working or how well patients are following the diet,” Silvester says.

Moreover, tolerance to gluten can vary in celiac disease. Some children have symptoms despite being (apparently) on a gluten-free diet. Others have no symptoms after a gluten exposure, yet show severe atrophy of the nutrient-absorbing villi on intestinal biopsy. Villous atrophy poses a risk for complications, such as poor growth, anemia and osteoporosis.

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Science Seen: An intestinal toxin’s trick, a potential cancer fighter

Crystal structure of the C. difficile toxin bound to its receptor, causing intestinal damage
Adapted from Science May 11, 2018. DOI: 10.1126/science.aar1999

Clostridium difficile, also called “C. diff,” causes severe gastrointestinal tract infections and tops the CDC’s list of urgent drug-resistant threats. In work published in Nature in 2016, Min Dong, PhD, and colleagues found the elusive portal that enables a key C. diff toxin, toxin B, to enter the intestines’ outer cells and break down the intestinal barrier (above right).

Interestingly, the same portal, known as the Frizzled receptor, also receives signals that maintain the intestine’s stem cells. When toxin B docks, it blocks these signals, carried by a molecule known as Wnt. But exactly how it all works remained a puzzle — until new research published today in Science.

Liang Tao, PhD in Dong’s lab, working with the labs of Rongsheng Jin, PhD, at UC-Irvine, and Xi He, PhD, at Boston Children’s, captured the crystal structure of a fragment of toxin B (in orange above) as it joined to the Frizzled receptor (in green). The structure revealed lipid molecules within the Frizzled receptor (in yellow and red) that play a central role. Normally, when Wnt binds to Frizzled, it nudges these lipids aside. But the team showed that when the toxin fragment binds to Frizzled, it locks these lipids in place, preventing Wnt from engaging with the cell.

Just as stem cells rely on Wnt signaling for growth and regeneration, so do many cancers. Now that its mechanism is known, Dong thinks this toxin B fragment, which by itself isn’t toxic, could be a useful anti-cancer therapeutic. They’re currently developing a new generation of Wnt signaling modulators and testing them in animal models of cancer. (For further information, contact Rajinder.Khunkun@childrens.harvard.edu of Boston Children’s Technology & Innovation Development Office.)

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Very-low-carb diet can safely curb blood sugar in type 1 diabetes, study suggests

very-low-carb diet shows promise in type 1 diabetes

David Ludwig, MD, PhD, an endocrinologist at Boston Children’s Hospital, has written popular books espousing a low-glycemic, low-carbohydrate diet for weight control. He has argued that high-glycemic diets are contributing to the epidemic of type 2 diabetes.  But he hadn’t given much thought to carbohydrate restriction for type 1 diabetes until 2016.

At a conference, Ludwig met a surgeon with type 1 diabetes who maintains normal hemoglobin A1c levels (indicating high blood sugar control) on a very-low-carbohydrate diet. This surprised and impressed him: he had never seen any patient with type 1 diabetes able to completely normalize their hemoglobin A1cs. Moreover, most diabetes experts discourage very-low-carb diets, believing they pose a risk for hypoglycemia, or a dangerous drop in blood sugar.

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Stick-on respiratory monitor allows early detection of breathing problems

Toddler wearing ExSpiron respiratory monitor
A mock-up of the ExSpiron monitoring a toddler’s breathing

Children can be at risk for compromised breathing after surgery or from conditions like asthma, congestive heart failure or sleep apnea. Opioid therapy and sedation for medical procedures can also depress breathing. Unless a child is sick enough to have a breathing tube, respiratory problems can be difficult to detect early. Yet early detection can mean the difference between life and death.

“There is currently no real-time objective measure,” says Viviane Nasr, MD, an anesthesiologist with Boston Children’s Hospital’s Division of Cardiac Anesthesia. “Instead, respiratory assessment relies on oximetry data, a late indicator of respiratory decline, and on subjective clinical assessment.”

A new device, recently cleared by the FDA for children 1 year and older in medical settings, provides an easy, noninvasive way to tell how much air the lungs are receiving in real time. It can signal problems as much as 15-30 minutes before standard pulse oximetry picks up low blood oxygenation, according to one study.

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Diagnosing autism in infants? EEG algorithms make accurate predictions

autism EEGs
EEG nets are easily slipped over an infant’s head and cause no discomfort. (Credit: Nelson Lab)

The earlier autism can be diagnosed, the more effective interventions typically are. But the signs are often subtle or can be misinterpreted at young ages. As a result, many children aren’t diagnosed until age 2 or even older. Now, a study shows that electroencephalograms (EEGs), which measure the brain’s electrical activity, can accurately predict or rule out autism spectrum disorder (ASD) in babies as young as 3 months old. It appears today in Scientific Reports.

The beauty of EEG is that it’s already used in many pediatric neurology or developmental pediatric settings. “EEGs are low-cost, non-invasive and relatively easy to incorporate into well-baby checkups,” says study co-author Charles Nelson, PhD, director of the Laboratories of Cognitive Neuroscience at Boston Children’s Hospital. “Their reliability in predicting whether a child will develop autism raises the possibility of intervening very early, well before clear behavioral symptoms emerge.”

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Failed cancer drug may extend life in children with progeria

child with progeria and damage to cell nucleus
Image: Wikimedia Commons. (Source: The Cell Nucleus and Aging: Tantalizing Clues and Hopeful Promises. Scaffidi P, Gordon L, Misteli T. PLoS Biology Vol. 3/11/2005, e395 doi:10.1371/journal.pbio.0030395)

Hutchinson-Gilford Progeria Syndrome, better known as progeria, is a highly rare genetic disease of premature aging. It takes a cruel toll: Children begin losing body fat and hair, develop the thin, tight skin typical of elderly people and suffer from hearing loss, bone problems, hardening of the arteries, stiff joints and failure to grow. They die at an average age of 14½, typically from heart disease resembling that of old age.

An observational study published yesterday in the Journal of the American Medical Association suggests that a drug called lonafarnib, originally developed as a potential cancer treatment, can extend these children’s lives.

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Families and data scientists build insights on Phelan-McDermid syndrome

querying stacks of data

This is the third year that Jacob Works has made the trip down to Boston Children’s Hospital from Maine. With research assistant Haley Medeiros, he looks at pictures, answers questions, manipulates blocks and mimes actions like knocking on a door. His father, Travis, and another research assistant look on through a window.

“At first, we had to practically bribe him with an iPad with every task,” Travis says. “This year he’s more excited, because he understands more and is more confident and able to share more.”

Jacob, 11, was diagnosed in 2011 with Phelan-McDermid Syndrome, a rare genetic condition that typically causes children to be born “floppy,” with low muscle tone, and to have little or no speech, developmental delay and, often, autism-like behaviors. At the time, Jacob was one of about 800 known cases. But through chromosomal microarray testing, introduced in just the past decade for children with autism symptoms, more cases are being picked up.

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Snaps from the lab: Developing better autism interventions

How can we better understand and support people with autism? And how can we tell if an intervention is working? Those are among the questions being asked in the Faja Laboratory, where Susan Faja, PhD, and her team study social and cognitive development in children, teens and young adults with autism spectrum disorder (ASD), using a variety of tools.

Originally on Snapchat, this video walks through some of these studies, including:

  • Individual Development of Executive Attention (IDEA), looking at executive functioning in 2- to 6-year-olds with autism, developmental disability or no developmental concerns. Executive functions include the ability to plan, manage complex or conflicting information, problem-solve and shift between different rules in different situations. By observing young children while they play hands-on tabletop games, Faja’s team is trying to find out: do kids with autism have problems with executive functioning early on, or do problems emerge later as a result of autism itself? The study is an extension of the ongoing GAMES project for 7- to 11-year-olds, in which children play video games designed to boost their executive functions. Faja is also looking to teach parents to use the games with their children at home.
  • Autism Biomarkers Consortium for Clinical Trials (ABC-CT), a multi-institution study that’s seeking objective, reliable measurements of social function and communication in people with autism. “Language, IQ and social assessments are not so sensitive when you’re looking for changes in autism symptoms, especially subtle ones,” says Faja. So her team is using physiologic measures — like EEGs to measure brain activity and eye-tracking technology to measure visual attention — and correlating them with behavioral and cognitive assessments. The ultimate goal is to validate a set of tools that can be used in clinical trials — and in day-to-day practice — to objectively measure and predict how children with ASD will respond to treatment.​
  • Competence in Romance and Understanding Sexual Health (CRUSH), a new study, will enroll young adults with autism and their parents. The goal is to develop curriculum around dating and sexual health that meets the needs of the ASD population, starting with interviews to determine their needs and interests. No evidence-based curricula currently exist for adults on the spectrum, says Faja.

Learn more about current and future projects in the Faja Lab.

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