The platelet whisperers

by Tom Ulrich on March 27, 2014

Finding the switch that gets megakaryocytes to produce platelets

To manufacture platelets in the laboratory, we need to find the switch that starts their production.

Looking down at my bandaged finger—a souvenir of a kitchen accident a few nights prior—Joseph Italiano, PhD, smiles and says to me, “You should have come by, we could’ve given you some platelets for that.”

The problem is that Italiano really couldn’t; he needs every platelet his lab can put its hands on. A platelet biologist in Boston Children’s Hospital’s Vascular Biology Program, Italiano is trying to find ways to manufacture platelets at a clinically useful scale.

To do that, he needs to develop a deep understanding of the science of how the body produces platelets, something that no one has at the moment.

The path by which blood stem cells develop into megakaryocytes—the bone marrow cells that produce and release platelets into the bloodstream—is already known, Italiano says. We also know that platelets are essentially fragments of megakaryocytes that break off in response to some signal.

But that’s where our knowledge of platelet production largely ends. “Megakaryocytes themselves are something of a black box,” Italiano explains. “If you microinject the cytoplasm of an active megakaryocyte into a resting megakaryocyte, it will start to produce platelets as well. But we don’t know what factor or factors cause them to start platelet production.”

As Italiano and his laboratory peer into that black box, they know the stakes are big. Because in the end, they want to greatly reduce doctors’ and patients’ dependence on donated platelets. Full story »

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MRI images showing isotropic diffusion in autism

A new MRI computational technology (above right) captures differences in water diffusion in the brain across a population of children with autism as compared with controls. This non-directional, “isotropic” diffusion pattern, not evident with conventional diffusion tensor imaging (DTI), may be an indicator of brain inflammation.

Diffusion tensor imaging (DTI), a form of magnetic resonance imaging, has become popular in neuroscience. By analyzing the direction of water diffusion in the brain, it can reveal the organization of bundles of nerve fibers, or axons, and how they connect—providing insight on conditions such as autism.

But conventional DTI has its limits. For example, when fibers cross, DTI can’t accurately analyze the signal: the different directions of water flow effectively cancel each other out. Given that an estimated 60 to 90 percent of voxels (cubic-millimeter sections of brain tissue) contain more than one fiber bundle, this isn’t a minor problem. In addition, conventional DTI can’t interpret water flow that lacks directionality, such as that within the brain’s abundant glial cells or the freely diffusing water that results from inflammation—so misses part of the story. Full story »

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3D printed plastic model of a patient's skull John Meara craniofacial anomaliesA picture may be worth a thousand words, but there’s something about holding an object in your hands that’s worth so much more. I realized this when John Meara, MD, DMD, handed me the skull of one of his patients.

I turned it over in my hands while Meara, Boston Children’s Hospital’s plastic surgeon-in-chief, pointed out features like the cranium’s asymmetric shape and the face’s malformed left orbit.

Mind you, it wasn’t actually Meara’s patient’s skull in my hands. In reality, I was holding a high-resolution, plastic 3D model printed from the patient’s CT scans.

The printer that made that model—and several other models I saw in the last month—is the centerpiece of a new in-house 3D printing service being built by Peter Weinstock, MD, PhD, and Boston Children’s Simulator Program.

3D printing technology has exploded in the last few years, to the point where anyone can buy a 3D printer like the MakerBot for a couple of thousand dollars or order 3D printed products from services like Shapeways. Adobe even recently added 3D printing support to Photoshop.

And 3D printing is already making a mark on medicine. Full story »

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heavy child running ShutterstockSchools have manned the front lines in the battle against childhood obesity. Through the Healthy, Hunger-Free Kids Act of 2010, First Lady Michelle Obama has promoted low-cal lunches, fresh produce and more. Now, she hopes to ban junk food and soda marketing in schools.

Are these efforts enough to turn the tide? Offering healthy foods and promoting physical activity at school may not be enough to negate the impact of other unhealthy influences in students’ homes and neighborhoods, according to Tracy Richmond, MD, MPH, of Boston Children’s Hospital’s Division of Adolescent Medicine.

Richmond recently published a study in PLOS One that looked at how a school’s physical activity or nutrition resources might influence fifth grade students’ body mass index (BMI).

The study focused on 4,387 students in Birmingham, Ala., Los Angeles and Houston. “We wanted to find out if certain schools look ‘heavier’ because of their composition—meaning that kids at higher risk of obesity, like African American girls or Hispanic boys, cluster within certain schools—or whether something structural in the school influences BMI, like the facilities or programs offered,” explains Richmond. Full story »

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Group handshake representing a consortiumDavid Altman is manager of marketing and communications in Boston Children’s Hospital’s Technology and Innovation Development Office.

Successful therapeutic development requires multiple stakeholders along the path from discovery to translation to clinical trials to FDA approval to market availability. At various points along this path, academia, industry, government, hospitals, nonprofits and philanthropists may work together. Would bringing these stakeholders together from start to finish lead to greater success?

A growing number of private-public consortia are launching in defined “pre-competitive” spaces where potential rivals collaborate to generate tools and data to accelerate biomedical research. In 1995, consortia were rare in health care: Only one was created. In 2012, 51 new consortia were launched, according to the organization Faster Cures.

Why? you may ask. Banding together in consortia can reduce costs, minimize failures and shorten the timeline to approval for new drugs. Full story »

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metaphor for investors "shark tank"If you’ve ever watched Shark Tank, you’ve gotten a taste of venture capitalists’ (VC) innate skepticism and hard-nosed ability to triage ideas. A recent webinar hosted by Cambridge Healthtech Associates offered a good practical “101” for scientists, inventors and clinical innovators—which we’ve distilled into the six tips below.

1.  Find the pain.

VCs will want to know what “pain points” you are solving—the burning need or unpleasant thing a customer wants to avoid or fix right now. In health care, this could be the need for a more definitive diagnostic test or a cost-saving option, or, for the pharmaceutical industry, the need to reduce R&D costs by finding a better way to pick compounds to take to clinical trial. Full story »

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Meat grinder protecting protein drugs from being ground up by cells clotting factors

Cells can grind up large protein drugs. A new technology may help those drugs escape and stay in the bloodstream longer.

Getting drugs to stay in the bloodstream longer is a big deal when it comes to treating chronic diseases. You see, a drug’s half-life—the time it takes for half of a given dose to be cleared from the body—determines how long its effect(s) last.

If a drug’s half-life is short—meaning it’s cleared quickly—patients will have to take the drug frequently. Given that someone with a chronic condition could be on the medication for many years—say, patients with severe hemophilia, who endure frequent infusions of clotting factors—a short half-life can translate into high cost. Depending on side effects and how the drug is administered, quality of life may also suffer.

Several years ago, Wayne Lencer, MD, a researcher in Boston Children’s Hospital’s Division of Gastroenterology, Hepatology and Nutrition, and his collaborators Richard Blumberg, MD, at Brigham and Women’s Hospital (BWH) and Neil Simister, DPhil, at Brandeis University came up with a way to make protein-based drugs like clotting factors stay in the circulation longer: by keeping cells from grinding them up.

The first drug based on their work—a form of the factor IX clotting factor—just passed a Phase III clinical trial reported in The New England Journal of Medicine. Full story »

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butterflyThe butterfly effect is defined as “the sensitive dependence on initial conditions, where a small change at one place in a deterministic nonlinear system can result in large differences to a later state.” In medicine, the identification of a rare disease or a genetic mutation may provide insights that spread well beyond the initial discovery.

And in genetics, scientists are learning just how widespread the effects are for mutations in one gene: filaminA (FLNA).

FLNA is a common cause of periventricular nodular heterotopia (PVNH), a disorder of neuronal migration during brain development. The syndrome was first described by the late Peter Huttenlocher, MD, and the gene was identified by Christopher Walsh, MD, PhD, of Boston Children’s Hospital.

In normal brain development, neurons form in the periventricular region, located around fluid-filled ventricles near the brain’s center, then migrate outward to form six onion-like layers. In PVNH, some neurons fail to migrate to their proper position and instead form clumps of gray matter around the ventricles. Full story »

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Did arbaclofen really fail in autism and fragile X?

Did arbaclofen really fail in autism and fragile X?

Walter Kaufmann, MD, is co-director of the Fragile X Syndrome Program and a member of the department of Neurology at Boston Children’s Hospital. He was site principal investigator for three arbaclofen trials sponsored by Seaside Therapeutics and currently advises the company on data analyses. This post is second in a two-part series on clinical trials in autism spectrum disorders. (Read part 1)

The outcomes of drug trials in autism spectrum disorder (ASD) have, to date, been mixed. While atypical neuroleptic drugs have been effective for treating disruptive behavior in people with autism and are FDA-approved for that purpose, no available psychotropic drug has improved the core symptoms of ASD, such as social interaction deficits or stereotypic behaviors.

The heterogeneity—diversity—of ASD in both causes and symptoms may explain treatment failures to some extent. However, we have also lacked drugs targeting the brain mechanisms that underlie ASD. For this reason, targeted trials in fragile X syndrome, informed by neurobiology, have raised hopes of finally addressing core autistic symptoms.

Fragile X syndrome is a genetic disorder in which ASD occurs in 15 to 40 percent of cases. Initial results from a Phase 2 trial using the GABA-B agonist arbaclofen demonstrated relatively selective improvements in social avoidance in a wide age-range sample of subjects. Full story »

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Hope for Rett syndrome?This post is the first in a two-part series on clinical trials in autism spectrum disorders. Read part 2.

In the world of neurodevelopmental disorders, an exciting trend is the emergence of specific molecular targets and treatments through genetic research. A case in point is IGF-1 therapy for Rett syndrome, a devastating disorder in girls that affects their ability to speak, walk, eat and breathe. It causes autism-like behaviors, intellectual disability and repetitive hand-wringing movements—a hallmark of the disorder.

A Phase I trial, published this week in the Proceedings of the National Academy of Sciences Early Edition, has modest but consistent results suggesting improvements in some salient features of the disorder.

Current treatments for Rett syndrome address only the symptoms and comorbidities, such as seizures, anxiety and scoliosis, but not the disease itself. But in 2007, findings in a mouse model (which even replicated the hand-wringing) changed how scientists think about Rett and other neurodevelopmental disorders, previously thought to be untreatable. Full story »

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