Gene Therapy Increases Stem Cell Recruitment to Heart and Improves Heart Function


Data from a Phase 2 clinical trial is creating quite a stir in cardiology circles. According to the findings of this study, the single administration of a gene on a non-viral-derived plasmid improves cardiac structure, function, serum biomarkers and clinical status in patients with severe ischemic heart failure one year after treatment.

The results from the final 12-months of the Phase 2 STOP-HF clinical trial for the JVS-100 treatment were presented at the European Society of Cardiology – Heart Failure 2015 meeting by the developer of this technology: Juventas Therapeutics Inc. The founder of Juventas, Marc Penn, M.D., Ph.D., FACC, is also the medical officer and director of Cardiovascular Research and Cardiovascular Medicine Fellowship at Summa Health in Akron, Ohio. Dr. Penn presented the results of this randomized, double-blind, placebo-controlled STOP-HF trial, which included treatments on 93 patients at 16 different clinical centers in the United States.

“The results from STOP-HF demonstrate that a single administration of 30 mg of JVS-100 has the potential to improve cardiac function, structure, serum biomarkers and clinical status in a population with advanced chronic heart failure who are symptomatic and present with poor cardiac function,” stated Dr. Penn. “These findings combined with our deep understanding of SDF-1 biology will guide future clinical trials in which we plan to prospectively study the patient population that demonstrated the most pronounced response to JVS-100. In addition, we will further our understanding of JVS-100 by determining if a second administration of drug may enhance benefits beyond those we observed with a single administration.”

These study. some patients received a 30 mg dose of JVS-100 while others received a placebo.  Patients who received JVS-100 showed definite improvements 12 months after treatment.  The cardiac function and heart structure of the patients who received JVS-100 were far better than those who had received the placebo.  JVS-100-treated patients showed a changed in left ventricle ejection fraction of 3.5% relative to placebo, and left ventricular end-systolic volume of 8.5 ml over placebo.  When patients were asked to walk for six minutes, the JVS-100-treated patients were better than patients who had received the placebo.  Likewise, when patients were given the Minnesota Living with Heart Failure Questionnaire, the JVS-100-treat patients had a better score than those who had received the placebo.  Also, there were no unanticipated serious adverse events related to the drug reported for the study.

JVS-100 is a non-viral DNA plasmid gene therapy. Plasmids are small circles of DNA that are relatively easy to manipulate, grow and propagate in bacterial cells. In the case of the JV-100 treatment, the plasmid encodes a protein called stromal cell-derived factor 1 (SDF-1). SDF-1 is a naturally occurring signaling protein that recruits stem cells from bone marrow to the site of SDF-1 expression. SDF-1, therefore, acts as a stem cell recruitment factor that summons stem cells to the places where they are needed.

When JV-100 is delivered directly to a site of tissue injury, it induces the expression of SDF-1 protein into the local environment for a period of approximately three weeks. SDF-1 secretion creates a homing signal that recruits the body’s own stem cells to the site of injury to induce tissue repair and regeneration.

Juventas is developing JVS-100 into a treatment of advanced chronic cardiovascular disease, including heart failure and late stage peripheral artery disease.

These improvements in heart function are relatively modest.  Therefore, it is difficult to get too excited about these results.  Also, Alexey Bersenev, a umbilical cord stem cell researcher, noted that the primary end points (or goalposts) for this trial were not met, and that makes this an unsuccessful trial.  Despite this bad news, JV-100 does seem to be safe, and the theory seems sound, even if the results are more than a little underwhelming.

Vascular Progenitors Made from Induced Pluripotent Stem Cells Repair Blood Vessels in the Eye Regardless of the Site of Injection


Johns Hopkins University medical researchers have reported the derivation of human induced-pluripotent stem cells (iPSCs) that can repair damaged retinal vascular tissue in mice. These stem cells, which were derived from human umbilical cord-blood cells and reprogrammed into an embryonic-like state, were derived without the conventional use of viruses, which can damage genes and initiate cancers. This safer method of growing the cells has drawn increased support among scientists, they say, and paves the way for a stem cell bank of cord-blood derived iPSCs to advance regenerative medical research.

In a report published Jan. 20 in the journal Circulation, Johns Hopkins University stem cell biologist Elias Zambidis and his colleagues described laboratory experiments with these non-viral, human retinal iPSCs, that were created generated using the virus-free method Zambidis first reported in 2011.

“We began with stem cells taken from cord-blood, which have fewer acquired mutations and little, if any, epigenetic memory, which cells accumulate as time goes on,” says Zambidis, associate professor of oncology and pediatrics at the Johns Hopkins Institute for Cell Engineering and the Kimmel Cancer Center. The scientists converted these cells to a status last experienced when they were part of six-day-old embryos.

Instead of using viruses to deliver a gene package to the cells to turn on processes that convert the cells back to stem cell states, Zambidis and his team used plasmids, which are rings of DNA that replicate briefly inside cells and then are degraded and disappear.

Next, the scientists identified and isolated high-quality, multipotent, vascular stem cells that resulted from the differentiation of these iPSC that can differentiate into the types of blood vessel-rich tissues that can repair retinas and other human tissues as well. They identified these cells by looking for cell surface proteins called CD31 and CD146. Zambidis says that they were able to create twice as many well-functioning vascular stem cells as compared with iPSCs made with other methods, and, “more importantly these cells engrafted and integrated into functioning blood vessels in damaged mouse retina.”

Working with Gerard Lutty, Ph.D., and his team at Johns Hopkins’ Wilmer Eye Institute, Zambidis’ team injected these newly iPSC-derived vascular progenitors into mice with damaged retinas (the light-sensitive part of the eyeball). The cells were injected into the eye, the sinus cavity near the eye or into a tail vein. When Zamdibis and his colleagues took images of the mouse retinas, they found that the iPSC-derived vascular progenitors, regardless of injection location, engrafted and repaired blood vessel structures in the retina.

“The blood vessels enlarged like a balloon in each of the locations where the iPSCs engrafted,” says Zambidis. Their vascular progenitors made from cord blood-derived iPSCs compared very well with the ability of vascular progenitors derived from fibroblast-derived iPSCs to repair retinal damage.

Zambidis says that he has plans to conduct additional experiments in diabetic rats, whose conditions more closely resemble human vascular damage to the retina than the mouse model used for the current study, he says.

With mounting requests from other laboratories, Zambidis says he frequently shares his cord blood-derived iPSC with other scientists. “The popular belief that iPSCs therapies need to be specific to individual patients may not be the case,” says Zambidis. He points to recent success of partially matched bone marrow transplants in humans, shown to be as effective as fully matched transplants.

“Support is growing for building a large bank of iPSCs that scientists around the world can access,” says Zambidis, although large resources and intense quality-control would be needed for such a feat. However, Japanese scientists led by stem-cell pioneer Shinya Yamanaka are doing exactly that, he says, creating a bank of stem cells derived from cord-blood samples from Japanese blood banks.

Safe and Efficient Cell Reprogramming Inside a Living Animal


Research groups at the University of Manchester, and University College, London, UK, have developed a new technique for reprogramming adult cells into induced pluripotent stem cells that greatly reduces the risk of tumor formation.

Kostas Kostarelos, who is the principal investigator of the Nanomedicine Lab at the University of Manchester said that he and his colleagues have discovered a safe protocol for reprogramming adult cells into induced pluripotent stem cells (iPSCs). Because of their similarities to embryonic stem cells, many scientist hope that iPSCs are a viable to embryonic stem cells.

How did they do it? According to Kostarelos, “We have induced somatic cells within the liver of adult mice to transient behave as pluripotent stem cells,” said Kostarelos. “This was done by transfer for four specific gene, previously described by the Nobel-prize winning Shinya Yamanaka, without the use of viruses but simply plasmid DNA, a small circular, double-stranded piece of DNA used for manipulating gene expression in a cell.”

This technique does not use viruses, which was the technique of choice in Yamanaka’s research to get genes into cells. Viruses like the kind used by Yamanaka, can cause mutations in the cells. Kostarelos’ technique uses no viruses, and therefore, the mutagenic properties of viruses are not an issue.

Kostarelos continued, “One of the central dogmas of this emerging field is that in vivo implantation of (these stem) cells will lead to their uncontrolled differentiation and the formation of a tumor-like mass.”

However, Kostarelos and his team have determined that the technique they designed does not show this risk, unlike the virus-based methods.

“[This is the ] only experimental technique to report the in vivo reprogramming of adult somatic cells to plurpotentcy using nonviral, transient, rapid and safe methods,” said Kostarelos.

Since this approach uses circular plasmid DNA, the tumor risk is quite low, since plasmid DNA is rather short-lived under these conditions. Therefore, the risk of uncontrolled growth is rather low. While large volumes of plasmid DNA are required to reprogram these cells, the technique appears to be rather safe in laboratory animals.

Also, after a burst of expression of the reprogramming factors, the expression of these genes decreased after several days. Furthermore, the cells that were reprogrammed differentiated into the surrounding tissues (in this case, liver cells). There were no signs in any of the laboratory animals of tumors or liver dysfunction.

This is a remarkable proof-of-principle experiment that shows that reprogramming cells in a living body is fast and efficient and safe.

A great deal more work is necessary in order to show that such a technique can use useful for regenerative medicine, but it is certainly a glorious start.

 

Also involved in this paper were r, , and .