Stories about: Vascular Biology Program

Patients’ brain tissue unlocks the cellular hideout of Sturge-Weber’s gene mutation

A diagram of the skull and brain showing the leptomeninges, which is affected by Sturge-Weber syndrome
Sturge-Weber syndrome causes capillary malformations in the brain. They occur in the brain’s leptomeninges, which comprise the arachnoid mater and pia mater.

A person born with a port-wine birthmark on his or her face and eyelid(s) has an 8 to 15 percent chance of being diagnosed with Sturge-Weber syndrome. The rare disorder causes malformations in certain regions of the body’s capillaries (small blood vessels). Port-wine birthmarks appear on areas of the face affected by these capillary malformations.

Aside from the visible symptoms of Sturge-Weber, there are also some more subtle and worrisome ones. Sturge-Weber syndrome can be detected by magnetic resonance imaging (MRI). Such images can reveal a telltale series of malformed capillaries in regions of the brain. Brain capillary malformations can have potentially devastating neurological consequences, including epileptic seizures.

Frustratingly, since doctors first described Sturge-Weber syndrome over 100 years ago, the relationship between brain capillary malformations and seizures has remained somewhat unexplained. In 2013, a Johns Hopkins University team found a GNAQ R183Q gene mutation in about 90 percent of sampled Sturge-Weber patients. However, the mutation’s effect on particular cells and its relationship to seizures still remained unknown.

But recently, some new light has been shed on the mystery. At Boston Children’s Hospital, Sturge-Weber patients donated their brain tissue to research after it was removed during a drastic surgery to treat severe epilepsy. An analysis of their tissue, funded by Boston Children’s Translational Neuroscience Center (TNC), has revealed the cellular location of the Sturge-Weber mutation. The discovery brings new hope of finding ways to improve the lives of those with the disorder.

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Science seen: Oral cancer up close

oral squamous cell carcinoma oral cancer lymphatic system cancer metastasis

Oral squamous cell carcinoma (OSCC), a kind of oral cancer, affects some 30,000 Americans annually. It spreads through the lymphatic system and often has already metastasized by the time it’s diagnosed. The top image here, from a recent study in the American Journal of Pathology, is a healthy mouse tongue; the bottom is the swollen tongue of a mouse with OSCC. The cancerous tongue is overloaded with lymphatic vessels, appearing in blue and white, which help the tumor spread to the regional lymph nodes. The Bielenberg lab in Boston Children’s Hospital’s Vascular Biology Program is studying ways of blocking the progression of this and other cancers by inhibiting their spread through the lymphatic system. (Image: Bielenberg laboratory/Kristin Johnson)

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Targeting inflammation in sickle cell disease with fatty acids

sickle cell disease red blood cells
(OpenStax College/Wikimedia Commons)

Painful, tissue-damaging vaso-occlusive crises (a.k.a. pain crises) are one of the key clinical concerns in sickle cell disease (SCD). The characteristic C-shaped red blood cells of SCD become jammed in capillaries, starving tissues of oxygen and triggering searing pain. Over a patient’s life, these repeated rounds of oxygen deprivation (ischemia) can take a heavy toll on multiple organs.

There’s some debate as to why these crises take place—is the sickled cell’s shape and rigidity at fault, or are the blood vessels chronically inflamed and more prone to blockage? Either way, doctors can currently do little to treat vaso-occlusive crises, and nothing to prevent them.

The inflammation view, however, is leading some researchers to ask whether omega-3 fatty acids—which can alleviate inflammation—might be part of the solution. A recent mouse study in the journal Haematologica, led by Mark Puder, MD, PhD, of Boston Children’s Vascular Biology Program, and Carlo Brugnara, MD, of the hospital’s Department of Laboratory Medicine reveals some molecular clues and suggests that human trials of omega-3s might be a good next step.

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Can breast cancer run on cholesterol?

Breast cancer cholesterol ezetimibe Zetia angiogenesisYou are what you eat, the saying goes. For some conditions (think cardiovascular disease or type 2 diabetes), there are clear connections between diet, health and illness.

For breast cancer, the picture is less clear. Many epidemiologic and laboratory studies have examined the Western diet (in particular, cholesterol) and its relation to breast cancer, with conflicting results.

“There’s been a raging debate in the field,” says Christine Coticchia, PhD, who works in the laboratory of Boston Children’s Hospital’s Vascular Biology Program director, Marsha Moses, PhD. “The biology of cancer and of cholesterol are so complex, and there are many subsets of breast cancer. In order to find any connections, you have to ask very specific questions.”

Banding together with Keith Solomon, PhD, in Boston Children’s Urology Department,  Coticchia and Moses asked whether dietary cholesterol might encourage progression of the most aggressive, so-called “triple-negative” breast tumors. As they report in the American Journal of Pathology, they found a big impact, at least in mice. But it’s too early to say just yet that cutting back on cholesterol will help women avoid breast cancer.

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Capturing complexity: Modeling bone marrow on a chip

Bone marrow on a chip organs on chips Wyss Institute Donald Ingber
Microscopic view of the engineered bone with an opening exposing the internal trabecular bony network, overlaid with colored images of blood cells and a supportive vascular network that fill the open spaces in the bone marrow-on-a-chip. (James Weaver, Harvard's Wyss Institute)

We’ve had a lung on a chip, and a gut on a chip. Now researchers at the Wyss Institute for Biologically Inspired Engineering have added another tissue to their list of “organs-on-chips”— devices that mimic in vitro tissues’ in vivo structure and function for pharmaceutical discovery and testing. In a paper published in Nature Methods, a team led by Donald Ingber, MD, PhD, (a member of Boston Children’s Hospital’s Vascular Biology Program and founding director of the Wyss), announced that they have developed “bone marrow-on-a-chip.”

The sheer complexity of the new device sets it apart from the Wyss’s previous organs, reflecting the greater natural complexity of bone marrow.

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The platelet whisperers

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.

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A day in the life: A pediatric neurosurgeon’s vision

Ed Smith explains the moyamoya operation during a live webcast.

Lindsay Hoshaw contributed to this post.

It’s 7 a.m. and neurosurgeon
Ed Smith, MD
, is downing a Diet Coke as he reviews the MRIs of today’s patients. He sprints up a stairwell to greet his first patient in the pre-operating wing.

Thirteen-year-old Maribel Ramos, about to have brain surgery at Boston Children’s Hospital, sits in her bed fidgeting. Smith reassures her about the operation, promises they’ll shave off as little hair as possible, and gets Maribel to crack a smile by telling her he moonlights as a hairdresser.

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Rousing dormant tumors: Where’s the “on” switch?

Like a seed, a tumor can remain dormant for years. But what's the trigger that causes a tumor to switch from dormancy to aggressive growth? (OpenCage/Flickr)

Believe it or not, you—and I, and everyone around us—quite likely has cancer right now.

While just a third of us will be diagnosed with cancer in our lifetimes, more than 90 percent of us harbor dormant, microscopically small tumors—maybe just a few cells in size—that will never be cause for alarm.

“Most people will live their lives without these tumors growing any larger,” says Randy Watnick, PhD, a researcher in the Vascular Biology Program at Boston Children’s Hospital. “But why? What is the difference between tumors that remain dormant and those destined to grow?”

It’s no small question: As screening and diagnostic technologies improve (allowing us to detect tumors smaller and earlier), the risks of overtreatment rise. That’s fueling a need for better ways to sift potentially dangerous tumors out from ones that will stay quiet.

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