Here are some stem cell stories that caught our eye this past week. Some are groundbreaking science, others are of personal interest to us, and still others are just fun.

Transplanting cells to speed stroke recovery. Stroke remains one of the most common forms of death and disability, yet utilization of therapies that can break down the blood clots that cause most forms of stroke lags; these therapies are only effective when used within 3 to 4 hours of the stroke but most patients arrive at the hospital too late. Now scientists from Shanghai Jiao Tong University may have a different solution that can repair damage already done.

Scientists have recently been looking to stem cell transplantation as a way to restore blood vessels or brain tissue destroyed by a stroke, but early experiments revealed limited effectiveness. In this study, which was published this week in Stem Cell Reports, the researchers coaxed embryonic stem cells further along in the development process before implanting them—which appears to have done the trick.

Using animal models, the team—led by Dr. Wei-Qiang Gao—transplanted two different types of so-called ‘precursor cells’ which have the ability to turn into the major types of brain and blood-vessel cells, the types of cells that are lost during a stroke.

Gao argues that this kind of transplantation is superior to previous methods because the two types of precursor cells can actually support each other in order to promote cell growth, and thus lays the foundation for new stem cell-based therapies to speed up recovery for stroke survivors.

CIRM-Funded Clinical Trial to Treat HIV. A team comprised of the City of Hope in Los Angeles, Sangamo Biosciences and the University of Southern California have developed an innovative approach to eradicating HIV.

With support from a CIRM grant, the researchers are developing a combination stem cell and gene therapy approach that is based on the success of the so-called “Berlin patient,” an HIV-positive man who was essentially cured after a bone-marrow transplant to treat his leukemia. In this instance, the bone marrow donor had a unique HIV-resistant mutation. The transplant transferred this mutation to the Berlin patient, and scientists have since been looking for a way to replicate this mutation on a larger scale. As explained in this week’s news release:

“Using an enzyme called a zinc-finger nuclease (ZFN), the research team can …“edit” the HIV patient’s stem cell genes so that, like the Berlin patient’s donor, they can no longer produce the protein. No protein, no HIV infection. The virus might then disappear from the body.

This study will be the first trial of ZFN technology in human stem cells. Earlier clinical studies in HIV-positive patients show that the ZFN method is generally safe when used with white blood cells called lymphocytes. And in one patient, the therapy was associated with temporary control of HIV without antiviral medication.”

The team hopes to begin testing this approach by the fall of 2014 on HIV patients who have not responded well to traditional therapies. CIRM funds a team that uses a different approach to gene editing that began a clinical trial last summer. You can read about both on our HIV fact sheet.

Building a Better Heart Cell. Stanford stem cell scientist Dr. Joseph Wu and his team have devised an improved method for generating large batches of heart muscle cells, known as cardiomyocytes, faster and cheaper than ever before. This new technique, described in the latest issue of Nature Methods, solves a long-standing problem in the field of regenerative medicine. As Wu explained in the Stanford University School of Medicine’s blog Scope:

“In order to fully realize the potential of these cells in drug screening and cell therapy, it’s necessary to be able to reliably generate large numbers at low cost….[Our] system is highly reproducible, massively scalable and substantially reduces costs to allow the production of billions of cardiomyocytes.”

This research, which was supported by a grant from CIRM, stands to improve scientists’ ability to use patient-derived cells not only to better understand how a heart becomes a heart, but also to test drugs that treat various types of heart disease.