Stories about: bone marrow transplant

Rainbow-hued blood stem cells shed new light on cancer, blood disorders

color-coded blood stem cells
These red blood cells bear color tags made from random combinations of red, green and blue fluorescent proteins. Same-color cells originate from the same blood stem cell (Nature Cell Biology 2016, Henninger et al).

A new color-coding tool is enabling scientists to better track live blood stem cells over time, a key part of understanding how blood disorders and cancers like leukemia arise, report researchers in Boston Children’s Hospital’s Stem Cell Research Program.

In Nature Cell Biology today, they describe the use of their tool in zebrafish to track blood stem cells the fish are born with, the clones (copies) these cells make of themselves and the types of specialized blood cells they give rise to (red cells, white cells and platelets). Leonard Zon, MD, director of the Stem Cell Research Program and a senior author on the paper, believes the tool has many implications for hematology and cancer medicine since zebrafish are surprisingly similar to humans genetically.

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Where science connects with care: A Q&A with Leonard Zon

Leonard Zon in the lab

Leonard Zon, MD, is founder and director of the Stem Cell Research Program at Boston Children’s Hospital and an investigator with the Howard Hughes Medical Institute and the Harvard Stem Cell Institute. His laboratory research focuses on stem cell therapies for patients with cancer and blood disorders, using a high-throughput, automated system for screening potential drugs in zebrafish. Zon was cofounder of Scholar Rock and Fate Therapeutics and founder and past president of the International Society for Stem Cell Research.

Your hospital just received a #1 ranking from U.S. News & World Report. What does this mean relative to your role there?

I’ve been at Boston Children’s Hospital for 25 years, and it’s really satisfying to be at the premier institution for clinical care. And we’re very lucky to have one of the premier stem cell programs in the world. I have a strong sense that my impact on society is as a physician-scientist, bringing basic discoveries to the clinic. We’re able to have a huge impact on finding new diagnoses and new therapies for our children.

What inspires you to do your job every day?

As a hematologist I take care of patients who have devastating diseases – a variety of blood diseases and cancer. When I see these children, I’m always wondering, could there be ways to treating them that haven’t been thought of before? Successfully treating a child gives them an entire lifetime of health.

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Supercharged marrow transplant: Zebrafish reveal drugs that aid engraftment

Zebrafish stem cell engraftment bone marrow
(Jonathan Henninger and Vera Binder)

Bone marrow transplantation, a.k.a. stem cell transplantation, can offer a cure for certain cancers, blood disorders, immune deficiencies and even metabolic disorders. But it’s a highly toxic procedure, especially when a closely matched marrow donor can’t be found. Using stem cells from umbilical cord blood banked after childbirth could open up many more matching possibilities, making transplantation safer.

Except for one problem. “Ninety percent of cord blood units can’t be used because they’re too small,” says Leonard Zon, MD, who directs the Stem Cell Research Program at Boston Children’s.

But what if the blood stem cells in those units could be supercharged to engraft more efficiently in the bone marrow and grow their numbers faster? That’s been the quest of the Zon lab for the past seven years, in partnership with a see-through zebrafish called Casper.

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Live imaging captures how blood stem cells take root in the body

For years, the lab of Leonard Zon, MD, director of the Stem Cell Research Program at Boston Children’s Hospital, has sought ways to enhance bone marrow transplants for patients with cancer, serious immune deficiencies and blood disorders. Using zebrafish as a drug-screening platform, the lab has found a number of promising compounds, including one called ProHema that is now in clinical trials.

But truthfully, until now, Zon and his colleagues have largely been flying blind.

“Stem cell and bone marrow transplants are still very much a black box: cells are introduced into a patient and later on we can measure recovery of their blood system, but what happens in between can’t be seen,” says Owen Tamplin, PhD, in the Zon Lab. “Now we have a system where we can actually watch that middle step.”

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Taking the toxicity out of stem cell transplants

Colombian twins Miranda and Olivia Agudelo (with their parents) were the first patients in a clinical trial aimed at making the bone marrow transplant process less toxic.

One thing that most people don’t realize about stem cell transplants (also called bone marrow or hematopoietic stem cell transplants) is that for patients, the transplant itself is probably the easiest part of the process. The grueling part is the preparation for a transplant, called conditioning.

There’s been a lot done at Dana-Farber/Children’s Hospital Cancer Center (DF/CHCC) and elsewhere to make conditioning less toxic. With a new clinical trial in a rare genetic syndrome called dyskeratosis congenita (DC), doctors at DF/CHCC are taking an even bolder step.

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There is a cure for sickle cell disease…for some

Maryam Idan (center), a young Iraqi girl with sickle cell disease, was lucky: she could be cured with a stem cell transplant. Leslie Lehmann, MD, wants to make such transplants an option for more sickle cell patients.

I was surprised when chatting recently with Leslie Lehmann, MD, clinical director of the Stem Cell Transplantation Program at Dana-Farber/Children’s Hospital Cancer Center (DF/CHCC). She turned to me and asked, “Did you know there’s been a cure for sickle cell disease for nearly 40 years?”

I had to admit that I didn’t. I’ve always thought of sickle cell—a painful and debilitating disease caused by an inherited mutation that makes red blood cells stiffen into a characteristic sickled shape—as a chronic disease to be managed, not one that could be cured.

I’m not alone in that belief. Lehmann often asks this question when she give talks for medical students, residents and other physicians. Their reaction is puzzlement, then a shaking of heads.

The cure is there, though. It’s a stem cell (aka bone marrow) transplant. The catch is that it’s not available to everyone—but for reasons that Lehmann thinks can be overcome.

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Radiation sickness: A two-drug combination could block radiation’s double hit

A two-drug combination could help raise the odds of surviving toxic doses of radiation released through accidents like those at Chernobyl (above) or Fukushima, or by a nuclear or radiological weapon. (Kamil Porembinski/Flickr)

Radiation can have its benefits – look at radiation therapy for cancer, or imaging technologies like X-rays and CT scans that use radiation to peer within our bodies. But high doses, from malfunctioning medical equipment, accidents like those at Chernobyl or Fukushima, or nuclear or radiological weapons, can be toxic or even lethal.

Right now, there are treatments in development that could raise the odds of surviving exposure to toxic doses of radiation, but only if given within a few minutes or hours of exposure. Ofer Levy of Children’s Division of Infectious Diseases and his collaborator Eva Guinan at Dana-Farber Cancer Institute have hit upon a new-two drug combination that markedly increased survival in mice when given as late as 24 hours after exposure.

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Stem cell experiments in genetic blood diseases

The green tips of these chromosomes are telomeres, whose length is a measure of cellular "aging" and determines how many times a cell can divide.

In a roomful of kids’ cancer specialists, like those listening to the keynote speech by George Daley, closing an international pediatric oncology meeting in Boston, the Myc gene is better known as a mutated weapon of mass destruction.

But this driver of cancer growth is also part of a four-gene cocktail that can reprogram an adult skin cell back into an embryonic-like stem cell that holds great therapeutic potential.

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