Stories about: Regenerative medicine

Novel therapeutic cocktail could restore fine motor skills after spinal cord injury and stroke

CST axons sprout from intact to injured side
Therapeutic mixture induces sprouting of axons from healthy (L) into the injured (R) side of the spinal cord.

Neuron cells have long finger-like structures, called axons, that extend outward to conduct impulses and transmit information to other neurons and muscle fibers. After spinal cord injury or stroke, axons originating in the brain’s cortex and along the spinal cord become damaged, disrupting motor skills. Now, reported today in Neuron, a team of scientists at Boston Children’s Hospital has developed a method to promote axon regrowth after injury.

Read Full Story | Leave a Comment

Optic nerve regeneration: One approach doesn’t fit all

alpha retinal ganglion cells optic nerve regeneration
Alpha-type retinal ganglion cells (RGCs) in part of an intact mouse retina. The cell axons lead to the optic nerve head (top right) and then exit into the optic nerve. The alpha RGCs are killed by the transcription factor SOX11 despite its pro-regenerative effect on other types of RGCs. (Fengfeng Bei)

Getting a damaged optic nerve to regenerate is vital to restoring vision in people blinded through nerve trauma or disease. A variety of growth-promoting factors have been shown to help the optic nerve’s retinal ganglion cells regenerate their axons, but we are still far from restoring vision. A new study published yesterday in Neuron underscores the complexity of the problem.

A research team led by Fengfeng Bei, PhD, of Brigham and Women’s Hospital, Zhigang He, PhD, and Michael Norsworthy, PhD, of Boston Children’s Hospital, and Giovanni Coppola, MD, of UCLA conducted a screen for transcription factors that regulate the early differentiation of RGCs, when axon growth is initiated. While one factor, SOX11, appeared to be critical in helping certain kinds of RGCs regenerate their axons, it simultaneously killed another type — alpha-RGCS (above)— when tested in a mouse model.

At least 30 types of retinal ganglion cell message the brain via the optic nerve. “The goal will be to regenerate as many subtypes of neurons as possible,” says Bei. “Our results here suggest that different subtypes of neurons may respond differently to the same factors.”

Read Full Story | Leave a Comment

Helping tissue grafts build a blood supply: Less is more

blood vessels in vivo

For a tissue graft to survive in the body — whether it’s a surgical graft or bioengineered tissue — it needs to be nourished by blood vessels, and these vessels must connect with the recipient’s circulation. While scientists know how to generate blood vessels for engineered tissue, efforts to get them to connect with the recipient’s vessels have mostly failed.

“Surgeons will tell you that when putting tissue in a new location in the body, the small blood vessels don’t connect at the new site,” says Juan Melero-Martin, PhD, a researcher in Cardiac Surgery in Boston Children’s Hospital. “If you want to engineer a tissue replacement, you’d better understand how the vessels get connected, because if the vessels go, the graft goes.”

Melero-Martin and colleagues have uncovered several strategies to help these connections form, as they describe online today in Nature Biomedical Engineering. The strategies could help improve the success of such procedures as heart patching, bone grafting, fat transplants and islet transplantation.

Read Full Story | Leave a Comment

Medical milestone: Making blood stem cells in the lab

blood stem cells
The gradation of pink-to-blue cells illustrates the transition from hemogenic endothelial cells to blood progenitor cells during normal embryonic blood development. Daley, Sugimura and colleagues recreated this process in the lab, then added genetic factors to produce a mix of blood stem and progenitor cells. (O’Reilly Science Art)

Pluripotent stem cells can make virtually every cell type in the body.  But until now, one type has remained elusive: blood stem cells, the source of our entire complement of blood cells.

Since human embryonic stem cells (ES cells) were isolated in 1998, scientists have tried to get them to make blood stem cells. In 2007, the first induced pluripotent stem (iPS) cells were made from human skin cells, and have since been used to generate multiple cell types, such as neurons and heart cells.

But no one has been able to make blood stem cells. A few have have been isolated, but they’re rare and can’t be made in enough numbers to be useful.

Now, the lab of George Daley, MD, PhD, part of Boston Children’s Stem Cell Research program as finally hit upon a way to create blood stem cells in quantity, reported today in Nature.

Read Full Story | Leave a Comment

Potential cure for diabetes may be in the stomach

diabetes stomach beta cells
The yellow-green cells in this “mini-stomach” are capable of making insulin. The mini-organ was made from biopsied cells from mouse stomachs, with reprogramming factors added.

If only there were a cure. David Breault, MD, PhD, associate chief of the Division of Endocrinology at Boston Children’s Hospital, was seeing patient after patient with Type I diabetes. Children facing lifetimes of insulin injections, special diets and the threat of long-term complications including blindness, heart disease and kidney failure.

Breault knew that patients with type I diabetes mysteriously destroy their own insulin-producing beta cells. He had read reports of researchers transplanting beta cells to supplement insulin. These transplants, even when successful, required powerful immunosuppressant medications to prevent patients’ immune systems from attacking the donor cells.

But Breault was also aware that investigators had, for a decade, been looking to stem cells as the source of a constantly renewing supply of beta cells. Advancing that promise, he has now found a way to convert patients’ own cells — from the stomach and intestine — into beta cells that produce insulin.

Read Full Story | Leave a Comment

Stem cells and birth defects: Could gastroschisis be treated in utero?

gastroschisis birth defects
Although Gianna was treated surgically, Dario Fauza, MD, hopes to someday use stem cells from the amniotic fluid, multiplied and returned to the womb, to naturally heal gastroschisis and other birth defects. (Courtesy Danielle DeCarlo)

Except when spreading awareness about her condition, 6-year-old Gianna DeCarlo prefers not to wear two-piece bathing suits because of the long vertical scar on her stomach. “Even though nobody’s said anything, she feels like she’ll be made fun of,” says her mother, Danielle. “I do what I can to make her love her body.”

Gianna doesn’t remember her three surgeries or the nasogastric tube she needed as an infant, before she was able to eat normally. She was born with gastroschisis, a striking birth defect in which the abdominal wall doesn’t seal fully during fetal development. As a result, her intestines developed outside her body. She was fed through an IV for several weeks, and was finally stitched fully shut at age 2.

Read Full Story | Leave a Comment

An inner ear in a dish

lab-grown inner ear organs
Images courtesy Eri Hashino

Could regenerative techniques restore hearing or balance by replacing lost sensory cells in the inner ear? Lab-created inner-ear organs, described today in Nature Communications, could provide helpful three-dimensional models for testing potential therapies.

The lab-built sac-like structure above, about 1 millimeter in size, contains fully-formed balance organs resembling the utricle and saccule, which sense head orientation and movement and send impulses to the brain. The tiny organs were built from mouse embryonic stem cells in a 3-D tissue culture in work led by Jeffrey Holt, PhD, of the F.M. Kirby Neurobiology Center at Boston Children’s Hospital and Eri Hashino, PhD, of the University of Indiana.

Read Full Story | Leave a Comment

Inside bridge-enhanced ACL repair

An anterior cruciate ligament (ACL) tear can be a devastating sports injury. Every year, 400,000 people, many of them teen and young adult athletes, sustain ACL injuries or tears. Martha Murray, MD, an orthopedic surgeon at Boston Children’s Hospital, worked with a team of colleagues to create a new procedure known as bridge-enhanced ACL repair (BEAR) that encourages natural healing. Watch this animation to see how it works:

Why do surgeons need a better way to repair ACL injuries?

The current standard of care, surgical ACL reconstruction, is a good solution. But it is linked with a 20 percent risk of re-tearing the ACL, and many young patients face an increased risk of arthritis. Instead of removing the torn ACL and replacing it with a tendon graft, the BEAR technique uses a special protein-enriched sponge to encourage the torn ends to reconnect and heal. The researchers have completed a 20-patient safety trial and are enrolling additional patients in a 200-patient clinical study.

Learn more about Murray’s research.

Read Full Story | Leave a Comment

News notes: Headlines in science & innovation

An occasional roundup of news items Vector finds interesting.

Blood-brain barrier on chip

vector news - blood brain barrier chip
(Wyss Institute at Harvard University)

The blood-brain barrier protects the brain against potentially damaging molecules, but its gate-keeping can also prevent helpful drugs from getting into the central nervous system. Reporting in PLoS One, a team at the Wyss Institute for Biologically Inspired Engineering describes a 3-D blood-brain barrier on a chip — a hollow blood vessel lined with living human endothelial cells and surrounded by a collagen matrix bearing human pericytes and astrocytes.

Read Full Story | Leave a Comment

A bridge to a 21st century ACL repair

Tears of the knee’s anterior cruciate ligament — or ACL — are on the rise in middle school and high school athletes. The current treatment involves grafting in a piece of tendon from elsewhere in the body. It works very well, but requires six months to two years of post-op rehabilitation to regain strength in the knee and the place where the tendon was taken from (often the hamstring). Plus, up to 80 percent of patients develop arthritis within 15 years of the procedure.

Orthopedic surgeon Martha Murray, MD, wondered, “What if we could somehow stimulate the original ACL to heal back together?”

Read Full Story | Leave a Comment