Author: Nancy Fliesler

Monitoring mitochondria: Laser device tells whether oxygen is sufficient

Shining a laser-based device on a tissue or organ may someday allow doctors to assess whether it’s getting enough oxygen, a team reports today in the journal Science Translational Medicine.

Placed near the heart, the device can potentially predict life-threatening cardiac arrest in critically ill heart patients, according to tests in animal models. The technology was developed through a collaboration between Boston Children’s Hospital and device maker Pendar Technologies (Cambridge, Mass.).

“With current technologies, we cannot predict when a patient’s heart will stop,” says John Kheir, MD, of Boston Children’s Heart Center, who co-led the study. “We can examine heart function on the echocardiogram and measure blood pressure, but until the last second, the heart can compensate quite well for low oxygen conditions. Once cardiac arrest occurs, its consequences can be life-long, even when patients recover.”

In critically ill patients with compromised circulation or breathing, oxygen delivery is often impaired. The new device measures, in real time, whether enough oxygen is reaching the mitochondria, the organelles that provide cells with energy.

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Pediatric devices wanted: Boston Children’s Hospital and the Boston Pediatric Device Consortium launch $250,000 challenge

Boston Pediatric Device Strategic Partner Challenge opens

There’s generally little incentive for industry to develop medical devices for children: The pediatric market is small (most children are healthy) and clinical trials are harder to do in children.

“Innovation in medical devices with the potential to improve the health of children and adolescents continues to lag in comparison to those for adults,” says Pedro del Nido, MD, leader of the Boston Pediatric Device Consortium and Chief of Cardiac Surgery at Boston Children’s Hospital. 

This week, the Innovation and Digital Health Accelerator (IDHA) at Boston Children’s Hospital and the Boston Pediatric Device Consortium (BPDC) announced a national challenge to try to remedy this problem. The Boston Pediatric Device Strategic Partner Challenge will award up to $50,000 to entrepreneurs and innovators seeking to create novel pediatric medical devices, from a total pool of up to $250,000.

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3D organoids and RNA sequencing reveal the crosstalk driving lung cell formation

lung disease
A healthy lung must maintain two key cell populations: airway cells (left), and alveolar epithelial cells (right). (Joo-Hyeon Lee)

To stay healthy, our lungs have to maintain two key populations of cells: the alveolar epithelial cells, which make up the little sacs where gas exchange takes place, and bronchiolar epithelial cells (also known as airway cells) that are lined with smooth muscle.

“We asked, how does a stem cell know whether it wants to make an airway or an alveolar cell?” says Carla Kim, PhD, of the Stem Cell Research Program at Boston Children’s Hospital.

Figuring this out could help in developing new treatments for such lung disorders as asthma and emphysema, manipulating the natural system for treatment purposes.

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Bad to the bone: New light on the brain’s venous system… and on craniosynostosis

cerebral veins and skull development in a normal child
Normal skull and brain venous development in a young child (courtesy Tischfield et al).

A recent study rocked the neuroscience world by demonstrating what in retrospect seems obvious: the brain has its own lymphatic system to help remove waste. A new study, from the laboratory of Elizabeth Engle, MD, at Boston Children’s Hospital, sheds light on another critical, little-studied part of the brain’s drainage system: the dural cerebral veins that remove and reabsorb excess cerebrospinal fluid.

The story of these vessels, the cover article in the next Developmental Cell, is a great example of lab scientists and physicians joining to make fundamental discoveries in biology. Strangely, critical clues come from children with craniosynostosis, a congenital malformation in which the skull plates fuse together too early in prenatal development, resulting in abnormal head shapes and, often, neurologic complications.

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Immune gene guards against type 1 diabetes by changing the microbiome. Do early antibiotics undercut its effects?

type 1 diabetes microbiome antibiotics

The health of our immune system is increasingly linked with the health of our intestinal bacteria. A mouse study from Harvard Medical School now hammers this home for autoimmune disorders, in which the body attacks its own cells. It looked specifically at type 1 diabetes, in which the body destroys the cells that make insulin.

Scientists have long known that the human leukocyte antigen (HLA) complex of proteins (also known as the major histocompatibility complex, or MHC) keep autoimmune responses in check. Certain common variants of the HLA/MHC genes are known to protect against a type 1 diabetes. But until now, how these genes prevent autoimmune reactions has been a mystery.

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A metabolic treatment for pancreatic cancer?

nitrogen disposal is important to pancreatic cancer
Targeting an enzyme that helps dispose of excess nitrogen curbed malignant growth of pancreatic tumors in obese mice.

Pancreatic cancer has become the third leading cause of cancer mortality. Its incidence is rising in parallel with the rise in obesity, and it’s hard to treat: five-year survival still hovers at just 8 to 9 percent. A new study published online in Nature Communications finds early success with a completely new, metabolic approach: reducing tumors’ ability to get rid of excess nitrogen.

The researchers, led by Nada Kalaany, PhD, of Boston Children’s Hospital’s Division of Endocrinology and the Broad Institute of MIT and Harvard, provide evidence that targeting the enzyme arginase 2 (ARG2) can curb pancreatic tumor growth, especially in people who are obese.

“We found that highly malignant pancreatic tumors are very dependent on the nitrogen metabolism pathway,” says Kalaany.

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Botulism toxin X: Time to update the textbooks, thanks to genomic sequencing

botulinum toxin X
Botulinum toxin X is the first new botulinum toxin to be identified since 1969. (Jason Wilson/Flickr)

Botulism is a rare, potentially fatal paralyzing illness. It’s the reason we shouldn’t feed infants honey and why we need to take care in consuming home-canned foods: they can potentially contain nerve-damaging toxins produced by Clostridium botulinum. Botulinum toxin is classified as one of the six most dangerous potential bioterrorism agents.

There are seven known types of botulinum toxin. Toxins A and B were first identified in 1919, and first purified in 1946 and 1947, respectively. (Both are also used medically.) Toxins C, D, E and F eventually followed. The last, toxin G, was identified in 1969 in soil bacteria in Argentina.

And that’s where it’s stood until now. But to truly defend against botulism, we need to know all the toxins made by the various C. botulinum strains, since each requires a separate antibody to neutralize it.

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Pediatric heart surgeons eye sticky, stretchy, slug-inspired adhesive

Arion subfiscus, whose sticky mucus inspired the new surgical adhesive (H. Crisp/Wikimedia Commons)

It’s been a challenge to develop a surgical adhesive that sticks to wet surfaces and isn’t toxic. But it turns out a certain kind of slug is very good at secreting a sticky mucus that glues fast, apparently as a defense mechanism.

That provided the inspiration for a hydrogel “super” adhesive that could supplant surgical sutures, at least for some operations, and help medical devices stay in place. Researchers at the Wyss Institute for Biologically Inspired Engineering and Harvard’s School of Engineering and Applied Sciences (SEAS), led by David Mooney, PhD, report that the adhesive bound strongly to a variety of animal tissues, including skin, cartilage, artery, liver and heart.

Nikolay Vasilyev, MD, a coauthor on the paper, is interested in the adhesive’s potential for young patients with congenital heart disease. He is is a research scientist in Cardiac Surgery at Boston Children’s Hospital, and led cardiac studies in pig models. 

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Saving Vanessa part 2: Parent-driven science

DADA2 symptoms can be controlled with medications
Why did Vanessa’s mysterious rheumatologic condition cause her to have a stroke?

Two-year-old Vanessa had survived the unthinkable: two massive cerebral hemorrhages, nine days apart. Katherine Bell and her wife Nancy Mendoza felt immense relief at their daughter’s close call. But they wanted to know more. What had caused Vanessa’s strokes? Would there be more? Was the cause treatable?

The strokes were the culmination of a mysterious illness that had started with a rash. Because of high levels of inflammatory proteins in her blood, Vanessa’s rheumatologists, Pui Lee, MD PhD and Robert Sundel, MD, had given her a provisional, somewhat vague diagnosis of periodic fever syndrome.

“In rheumatology, we have to be comfortable with operating with a lot of unknowns,” Lee says.

But the strokes occurred despite three different anti-inflammatory treatments, which worked only temporarily. Bell, less comfortable with the unknowns, began searching the medical literature.

“It helped me feel calmer,” Bell says. “The more information I have, the less out of control I feel.”

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Training neurosurgeons in a rare hydrocephalus procedure, with a little help from Hollywood

ETV trainer

A 4-year-old has a progressively enlarging head and loss of developmental milestones: a clear case of hydrocephalus. He undergoes a minimally invasive endoscopic third ventriculostomy (ETV) to drain off the trapped cerebrospinal fluid.

This requires puncturing the floor of the brain’s third ventricle (fluid-filled cavity) with an endoscope — while avoiding a lethal tear in the basilar artery, which lies perilously close.

There are no good neurosurgical training models for this rare and scary operation.

“We semi-blindly poke a hole through the ventricle floor,” says Benjamin Warf, MD, director of Neonatal and Congenital Anomaly Neurosurgery at Boston Children’s Hospital. “To make the technique safer and to be able to train more people, it would be very helpful to make that hole in a way that’s less anxiety-provoking.”

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