Using 3D printer to develop treatment for spinal cord injury

3d-printed-device

3D printed device

Spinal cord injuries (SCIs) affect approximately 300,000 Americans, with about 18,000 new cases occurring per year. One of these patients, Jake Javier, who we have written about many times over the past several years, received ten million stem cells as part of a CIRM-funded clinical trial and a video about his first year at Cal Poly depicts how these injuries can impact someone’s life.

Currently, there is nothing that completely reverses SCI damage and most treatment is aimed at rehabilitation and empowering patients to lead as normal a life as possible under the circumstances. Improved treatment options are necessary both to improve patients’ overall quality of life, and to reduce associated healthcare costs.

Scientists at UC San Diego’s School of Medicine and Institute of Engineering in Medicine have made critical progress in providing SCI patients with hope towards a more comprehensive and longer lasting treatment option.

shaochen chen

Prof. Shaochen Chen and his 3D printer

In a study partially funded by CIRM and published in Nature Medicine, Dr. Mark Tuszynski’s and Dr. Shaochen Chen’s groups used a novel 3D printing method to grow a spinal cord in the lab.

Previous studies have seen some success in lab grown neurons or nerve cells, improving SCI in animal models. This new study, however, is innovative both for the speed at which the neurons are printed, and the extent of the neuronal network that is produced.

To achieve this goal, the scientists used a biological scaffold that directs the growth of the neurons so they grow to the correct length and generate a complete neuronal network. Excitingly, their 3D printing technology was so efficient that they were able to grow implants for an animal model in 1.6 seconds, and a human-sized implant in just ten minutes, showing that their technology is scalable for injuries of different sizes.

When they tested the spinal cord implants in rats, they found that not only did the implant repair the damaged spinal cord tissue, but it also provided sustained improvement in motor function up to six months after implantation.

Just as importantly, they also observed that blood vessels had infiltrated the implanted tissue. The absence of vascularized tissue is one of the main reasons engineered implants do not last long in the host, because blood vessels are necessary to provide nutrients and support tissue growth. In this case, the animal’s body solved the problem on its own.

In a press release, one of the co-first authors of the paper, Dr. Kobi Koffler, states the importance and novelty of this work:

“This marks another key step toward conducting clinical trials to repair spinal cord injuries in people. The scaffolding provides a stable, physical structure that supports consistent engraftment and survival of neural stem cells. It seems to shield grafted stem cells from the often toxic, inflammatory environment of a spinal cord injury and helps guide axons through the lesion site completely.”

In order to make this technology viable for human clinical trials, the scientists are testing their technology in larger animal models before moving into humans, as well as investigating how to improve the longevity of the neuronal network by introducing proteins into the scaffolds.

 

 

New approach could help turn back the clock and reverse damage for stroke patients

stroke

Stroke: courtesy WebMD

Stroke is the leading cause of serious, long-term disability in the US. Every year almost 800,000 people suffer from a stroke. The impact on their lives, and the lives of those around them can be devastating.

Right now the only treatment approved by the US Food and Drug Administration (FDA) is tissue plasminogen activator or tPA. This helps dissolve the blood clot causing most strokes and restores blood flow to the brain. However, to be fully effective this has to be administered within about 3-4 hours after the stroke. Many people are unable to get to the hospital in time and as a result suffer long-term damage, damage that for most people has been permanent.

But now a new study in Nature Medicine shows that might not be the case, and that this damage could even be reversible.

The research, done by a team at the University of Southern California (USC) uses a one-two punch combination of stem cells and a protein that helps those cells turn into neurons, the cells in the brain damaged by a stroke.

First, the researchers induced a stroke in mice and then transplanted human neural stem cells alongside the damaged brain tissue. They then added in a dose of the protein 3K3A-APC or a placebo.

hey found that mice treated with 3K3A-APC had 16 times more human stem-cell derived neurons than the mice treated with the placebo. Those neurons weren’t just sitting around doing nothing. USC’s Berislav Zlokovic, senior author of the paper, says they were actively repairing the stroke-induced damage.

“We showed that 3K3A-APC helps the grafted stem cells convert into neurons and make structural and functional connections with the host’s nervous system. No one in the stroke field has ever shown this, so I believe this is going to be the gold standard for future studies. Functional deficits after five weeks of stroke were minimized, and the mice were almost back to normal in terms of motor and sensorimotor functions. Synapses formed between transplanted cells and host cells, so there is functional activation and cooperation of transplanted cells in the host circuitry.”

The researchers wanted to make sure the transplanted cell-3K3A-ACP combination was really the cause of the improvement in the mice so they then used what’s called an “assassin toxin” to kill the neurons they had created. That reversed the improvements in the treated mice, leaving them comparable to the untreated mice. All this suggests the neurons had become an integral part of the mouse’s brain.

So how might this benefit people? You may remember that earlier this summer Stanford researchers produced a paper showing they had helped some 18 stroke patients, by injecting stem cells from donor bone marrow into their brain. The improvements were significant, including in at least one case regaining the ability to walk. We blogged about that work here

In that study, however, the cells did not become neurons nor did they seem to remain in the brain for an extended period. It’s hoped this new work can build on that by giving researchers an additional tool, the 3K3A-ACP protein, to help the transplanted cells convert to neurons and become integrated into the brain.

One of the other advantages of using this protein is that it has already been approved by the FDA for use in people who have experienced an ischemic stroke, which accounts for about 87 percent of all strokes.

The USC team now hope to get approval from the FDA to see if they can replicate their experiences in mice in people, through a Phase 2 clinical trial.

 

 

 

 

 

 

 

Stem cells could offer hope for deadly childhood muscle wasting disease

Duchenne muscular dystrophy (DMD) is a particularly nasty rare and fatal disease. It predominantly affects boys, slowly robbing them of their ability to control their muscles. By 10 years of age, boys with DMD start to lose the ability to walk; by 12, most need a wheelchair to get around. Eventually they become paralyzed, and need round-the-clock care.

There are no effective long-term treatments and the average life expectancy is just 25.

Crucial discovery

Duchenne MD team

DMD Research team: Photo courtesy Ottawa Hospital Research Inst.

But now researchers in Canada have made a discovery that could pave the way to new approaches to treating DMD. In a study published in the journal Nature Medicine, they show that DMD is caused by defective muscle stem cells.

In a news release Dr. Michael Rudnicki, senior author of the study, says this discovery is completely changing the way they think about the condition:

“For nearly 20 years, we’ve thought that the muscle weakness observed in patients with Duchenne muscular dystrophy is primarily due to problems in their muscle fibers, but our research shows that it is also due to intrinsic defects in the function of their muscle stem cells. This completely changes our understanding of Duchenne muscular dystrophy and could eventually lead to far more effective treatments.”

Loss and confused

DMD is caused by a genetic mutation that results in the loss of a protein called dystrophin. Rudnicki and his team found that without dystrophin muscle stem cells – which are responsible for repairing damage after injury – produce far fewer functional muscle fibers. The cells are also confused about where they are:

“Muscle stem cells that lack dystrophin cannot tell which way is up and which way is down. This is crucial because muscle stem cells need to sense their environment to decide whether to produce more stem cells or to form new muscle fibers. Without this information, muscle stem cells cannot divide properly and cannot properly repair damaged muscle.”

While the work was done in mice the researchers are confident it will also apply to humans, as the missing protein is almost identical in all animals.

Next steps

The researchers are already looking for ways they can use this discovery to develop new treatments for DMD, hopefully one day turning it from a fatal condition, to a chronic one.

Dr. Ronald Worton, the co-discoverer of the DMD gene in 1987, says this discovery has been a long-time coming but is both welcome and exciting:

“When we discovered the gene for Duchenne muscular dystrophy, there was great hope that we would be able to develop a new treatment fairly quickly. This has been much more difficult than we initially thought, but Dr. Rudnicki’s research is a major breakthrough that should renew hope for researchers, patients and families.”

In this video CIRM grantee, Dr. Helen Blau from Stanford University, talks about a new mouse model created by her lab that more accurately mimics the Duchenne symptoms observed in people. This opens up opportunities to better understand the disease and to develop new therapies.