Stem cell byproducts provide insight into cure for spina bifida

A diagram of an infant born with spina bifida, a birth defect where there is an incomplete closing of the backbone portion of the spinal cord. Photo courtesy of the Texas Children’s Hospital website.

Some of you might remember a movie in the early 2000s by the name of “Miracle in Lane 2”. The film is based on an inspirational true story and revolves around a boy named Justin Yoder entering a soapbox derby competition. In the movie, Justin achieves success as a soapbox derby driver while adapting to the challenges of being in a wheelchair.

Scene from “Miracle in Lane 2”

The reason that Justin is unable to walk is due to a birth defect known as spina bifida, which causes an incomplete closing of the backbone portion of the spinal cord, exposing tissue and nerves. In addition to difficulties with walking, other problems associated with this condition are problems with bladder or bowel control and accumulation of fluid in the brain.

According to the Center for Disease Control (CDC) , each year about 1,645 babies in the US are born with spina bifida, with Hispanic women having the highest rate of children born with the condition. There is currently no cure for this condition, but researchers at UC Davis are one step closer to changing that.

Dr. Aijun Wang examining cells under a microscope. He has identified stem cell byproducts that protect neurons. Photo courtesy of UC Regents/UC Davis Health

Dr. Aijun Wang, Dr. Diana Farmer, and their research team have identified crucial byproducts produced by stem cells that play an important role in protecting neurons. These byproducts could assist with improving lower-limb motion in patients with spina bifida.

Prior to this discovery, Dr. Farmer and Dr. Wang demonstrated that prenatal surgery combined with connective tissue (e.g. stromal cells) derived from stem cells improved hind limb control in dogs with spina bifida. Below you can see a clip of two English bulldogs with spina bifida who are now able to walk.

Their findings were published in the Journal of the Federation of American Societies for Experimental Biology on February 12, 2019.

The team will use their findings to perfect the neuroprotective qualities of a stem cell treatment developed to improve locomotive problems associated with spina bifida.

In a public release posted by EurekaAlert!, Dr. Wang is quoted as saying, “We are excited about what we see so far and are anxious to further explore the clinical applications of this research.”

The discovery and development of a treatment for spina bifida was funded by a $5.66 million grant from CIRM. You can read more about that award and spina bifida on a previous blog post linked here.

Support cells have different roles in blood stem cell maintenance before and after stress

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Expression of pleiotrophin (green) in bone marrow blood vessels (red) and stromal cells (white) in normal mice (left), and in mice 24 hours after irradiation (right). UCLA Broad Stem Cell Research Center/Cell Stem Cell

A new study published in the journal Cell Stem Cell, reveals how different types of cells in the bone marrow are responsible for supporting blood stem cell maintenance before and after injury.

It was already well known in the field that two different cell types, namely endothelial cells (which line blood vessels) and stromal cells (which make up connective tissue, or tissue that provides structural support for any organ), are responsible for maintaining the population of blood stem cells in the bone marrow. However, how these cells and the molecules they secrete impact blood stem cell development and maintenance is not well understood.

Hematopoietic stem cells are responsible for generating the multiple different types of cells found in blood, from our oxygen carrying red blood cells to the many different types of white blood cells that make up our immune system.

Dr. John Chute’s group at UCLA had previously discovered that a molecule called pleiotrophin, or PTN, is important for promoting self-renewal of the blood stem cell population. They did not, however, understand which cells secrete this molecule and when.

To answer this question, the scientists developed mouse models that did not produce PTN in different types of bone marrow cells, such as endothelial cells and stromal cells. Surprisingly, they saw that the inability of stromal cells to produce PTN decreased the blood stem cell population, but deletion of PTN in endothelial cells did not affect the blood stem cell niche.

Even more interestingly, the researchers found that in animals that were subjected to an environmental stressor, in this case, radiation, the result was reversed: endothelial cell PTN was necessary for blood stem cell renewal, whereas stromal cell PTN was not. While an important part of the knowledge base for blood stem cell biology, the reason for this switch in PTN secretion at times of homeostasis and disease is still unknown.

As Dr. Chute states in a press release, this result could have important implications for cancer treatments such as radiation:

“It may be possible to administer modified, recombinant versions of pleiotrophin to patients to accelerate blood cell regeneration. This strategy also may apply to patients undergoing bone marrow transplants.”

Another important consideration to take away from this work is that animal models developed in the laboratory should take into account the possibility that blood stem cell maintenance and regeneration is distinctly controlled under healthy and disease state. In other words, cellular function in one state is not always indicative of its role in another state.

This work was partially funded by a CIRM Leadership Award.

 

 

Finally a possible use for your excess fat; using it to fix your arthritic knee

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One of the most common questions we get asked at CIRM, almost every other day to be honest, is “are there any stem cell treatments for people with arthritis in their knees?” It’s not surprising. This is a problem that plagues millions of Americans and is one of the leading causes of disability in the US.

Sadly, we have to tell people that there are no stem cell treatments for osteoarthritis (OA) in the knee that have been approved by the Food and Drug Administration (FDA). There’s also a lack of solid evidence from clinical trials that the various approaches are effective.

But that could be changing. There’s a growing number of clinical trials underway looking at different approaches to treating OA in the knee using various forms of stem cells. Sixteen of those are listed at clinicaltrials.gov. And one new study suggests that just one injection of stem cells may be able to help reduce pain and inflammation in arthritic knees, at least for six months. The operative word here being may.

The study, published in the journal Stem Cells Translational Medicine,  used adipose-derived stromal cells, a kind of stem cell taken from the patient’s own fat. Previous studies have shown that these cells can have immune boosting and anti-scarring properties.

The cells were removed by liposuction, so not only did the patient’s get a boost for their knees they also got a little fat reduction. A nice bonus if desired.

The study was quite small. It involved 18 patients, between the ages of 50 and 75, all of whom had suffered from osteoarthritis (OA) in the knee for at least a year before the treatment. This condition is caused by the cartilage in the knee breaking down, allowing bones to rub against each other, leading to pain, stiffness and swelling.

One group of patients were given a low dose of the cells (23,000) injected directly into the knee, one a medium dose (103,000) and one a high dose (503,000).

Over the next six months, the patients were closely followed to see if there were any side effects and, of course, any improvement in their condition. In a news release, Christian Jorgensen, of University Hospital of Montpellier, the director of the study, said the results were encouraging:

“Although this phase I study included a limited number of patients without a placebo arm we were able to show that this innovative treatment was well tolerated in patients with knee OA and it provided encouraging preliminary evidence of efficacy. Interestingly, patients treated with low-dose ASCs significantly improved in pain and function compared with the baseline.”

The researchers caution that the treatment doesn’t halt the progression of OA and does not restore the damaged cartilage, instead it seems to help patients by reducing inflammation.

In a news article about the study Tony Atala, director of the Wake Forest Institute for Regenerative Medicine, in Winston-Salem, N.C. and the editor of Stem Cells Translational Medicine said the study offered the patients involved another benefit:

“In fact, most of the patients (in the study group) who had previously scheduled total knee replacement surgery decided to cancel the surgery. It will be interesting to see if these improvements are seen in larger groups of study participants.”

Interesting is an understatement.

But while this is encouraging it’s important to remember it was done in a small group of patients and needs to be replicated in a much larger group before we can draw any solid conclusions. It will also be important to see if the benefits last longer than six months.

We might not have to wait too long for some answers. The researchers are already running a 2-year trial involving 150 people in Europe.

We’ll let you know what they find.