Four years after Japan’s Fukushima nuclear plant disaster, the country is still not out of the woods, with the risk of mass radiation poisoning a continued risk. That is why the Fukushima Medical University’s Global Medical Science Center has signed a deal with Israel’s Pluristem Therapeutics to further develop the company’s PLX-R18 cells to treat acute radiation syndrome (ARS).
Under the deal, PLX-R18 cells will be studied primarily as a potential treatment for radiation-induced damage to the skin, lungs and gastrointestinal tract. The parties intend to develop pre-clinical models of radiation damage in these tissues, and then use them in trials; Pluristem will contribute PLX-R18 cells and scientific knowledge, while Fukushima Medical University will conduct the studies and provide the required resources.
Although out of the news, the Fukushima plant continues to pose major health risks. Four and a half years after the explosion and subsequent meltdown at the plant damaged in the earthquake and tsunami that hit northern Japan in March 2011, radiation continues to spread, both in Japan and abroad.
Just this week, the Woods Hole Oceanographic Institution issued a report saying that more sites off the coast of the western US were showing signs of radiation contamination. And in Japan itself, as many as a million people could die in the coming years from radiation-induced cancer, according to a report last month by Fairewinds Energy Education.
So far there have been just a few documented cases of cancer directly linked to the disaster, no one in Japan is taking anything for granted. While officials are doing what they can to clean up the site, they realize that they must also act to prevent a potential health emergency.
Enter Pluristem, a Haifa-based company that is developing a cure for acute radiation syndrome (ARS), also known as radiation disease, the mass destruction of tissues and cells caused by exposure to extremely high levels of radiation, such as a nuclear catastrophe.
ARS can cause lethal damage to the gastrointestinal tract, lung, skin and bone marrow, as well as other systems. But tests have shown that the stem-cell technology developed by Pluristem can prevent damage to cells affected by ARS. In tests conducted in Israel and the US, animals (mostly mice) that were subjected to total body irradiation and injected with human cytokines, showed significantly increased survival rates when treated with Pluristem’s PLX-RAD cells. The treatment essentially reversed the effects of radiation disease – which is especially hard on bone marrow – to a great extent.
While there are many companies today harvesting stem cells to develop therapeutic products, Pluristem was the first, and is still one of the only, companies doing that harvesting from human placenta.
According to Pluristem researchers, the placenta contains mesenchymal-like adherent stromal cells, which have been found by researchers to have significant therapeutic potential. The cells promote tissue repair, possibly by secreting biologically active substances, including cytokines, that modulate immune response, along with factors that enhance the growth of blood vessels. These cells stimulate the body’s own mechanisms to heal damaged tissues. And because placental cells themselves are immunoprivileged (meaning that they do not elicit an immunological response from the body, as other cells do), they can be used freely for any purpose, without requiring tissue matching.
Pluristem “harvests” the placenta from a hospital in northern Israel, where it is donated by women undergoing caesarean section births. The births are planned in advance, allowing the company to set up the equipment needed to ensure that the placenta is still living and not contaminated by the environment. It is then rushed to Pluristem’s facility, where it is processed into PLX (PLacental eXpanded) cells, for use in a variety of applications.
The company has conducted dozens of tests showing the efficacy of its solution, including several on animals that showed a very significant improvement in cases of radiation disease. According to one of the studies, mice showed a four-fold increase in their survival rate, accompanied by a corresponding weight regain, and a large increase in blood cell count, when treated with Pluristem PLX cells. Other tests have shown how injuries to limbs repair themselves much faster, even among individuals with severe injuries, arteriosclerosis, and other conditions.
The US National Institute of Allergy and Infectious Diseases (NIAID), part of the US National Institutes of Health (NIH), has been conducting its own study on how Pluristem’s technology could be useful to humans in the event of mass nuclear destruction. According to the company, the agency has been very positive about the results, to the extent that, along with Pluristem, it has already developed a plan for the creation, delivery and deployment of millions of doses of PLX-based radiation treatments.
The study will now be expanded to Fukushima Medical University, which, alongside the research supported by the US institutions, will help turn PLX-R18, Pluristem hopes, into a treatment, if not a cure, for ARS.
Data from a preclinical study, published in the peer-reviewed scientific journal PLOS One, suggest that PLX-R18 cells, administered intramuscularly, may be a highly effective off-the-shelf therapy for bone marrow failure following total body exposure to high doses of radiation. The work with the university’s Fukushima Global Medical Science Center will further evaluate the efficacy of intramuscular administration for systemic treatment of ARS, said Pluristem.
“The researchers at Fukushima have a strong interest in cell therapies that may offer a treatment for conditions caused by exposure to ionizing radiation,” said Pluristem CEO Zami Aberman. “We hope that this collaboration can advance efforts to safeguard populations around the world from illness related to radiation exposure.”
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