By Hannah Edelman
Boston University News Service
The applications of stem cells in the medical field have been a topic of both debate and breakthroughs in recent years. From drug safety testing to diseased tissue regeneration, scientists worldwide continue to find new uses and advancements.
But what are stem cells? Essentially, these cells are the building blocks of the human body. They are found primarily in the embryo and have no particular assigned function. This means that when stem cells divide, they have the potential to generate new types of specialized cells, such as nerve or bone cells.
Now, some stem cell researchers are applying their work to a new field: sustainability.
The application of stem cells in animal agriculture rather than humans is “counter-intuitive for most of the stem cell community,” Dr. Takanori Takebe, director of the Center for Stem Cell and Organoid Research and Medicine at Cincinnati Children’s, said.
Typically, scientists use animal stem cells as a transitional step in eventual clinical application in humans.
Takebe himself entered the field of stem cell research after interning at a liver transplant center in 2010, where he witnessed the need for organs far outweighed the supply. He decided to focus on an alternative approach to transplantation: growing livers from stem cells.
Takebe’s work attracted the International Society for Stem Cell Research (ISSCR) attention, who approached him two years ago about organizing a symposium on stem cells and sustainability. With the help of Sana Biotechnology Director Steve Kattman, he agreed and created the Stem Cells and Global Sustainability series. Due to COVID-19, the four-day event was held digitally in February over Zoom.
The symposium centered primarily on the interconnected themes of species conservation, climate change and commercial agriculture. Prior to this, Takebe said that stem cell researchers didn’t talk about agricultural applications.
“Nobody talked about meat,” Takebe said. “Nobody talked about fish. Nobody talked about manufacturing processes. I think it will give a very different flavor for the entire community so that we can potentially attract more people in our community to lean towards the different directions.”
One of the food industry representatives featured in the series was BlueNalu, a San Diego-based company that focuses on manufacturing seafood from cells. Lauran Madden, the company’s vice president of research and product development, focused specifically on the relationship between global warming and the seafood industry.
She explained that overfishing, pollution and rising ocean temperatures damage seafood supply chains; at the same time, the global consumption of seafood is continuing to increase.
“The more I learned about the food supply systems, the more [I] realized how vulnerable it is,” Madden said. “Creating these technologies to increase the supply will help both towards protecting our natural resources, but also towards ensuring food sustainability in the years and decades to come.”
The process of manufacturing a stem cell-based synthetic fish contains multiple steps. First, the cell of a desired fish species is isolated. Scientists then “feed” the cell nutrients, such as fats, sugars and salts, so that it multiplies and forms tissues. Finally, the grown cells are treated to resemble the look and texture of traditional seafood and “packaged,” much like at a traditional food-processing plant.
“I think that sometimes people take for granted all the things that we live and breathe every day,” Madden said. “Whether it’s our ability to exercise or the food we eat or the plants we grow, all of those are based in cells as the building blocks.”
Madden said that, in addition to preserving fish populations, this method of manufacturing avoids possible contamination with mercury and microplastics found in nature. It also eases the impact of viruses like COVID-19, which has caused multiple shortages in the meatpacking industry.
Takebe’s presentation at the symposium also addressed the pandemic, specifically in terms of its impact on the already endangered species of the Asiatic black bear. Bile produced in the bear’s liver and stored in its gallbladder has long been harvested for herbal medicine. The Chinese government is reportedly now recommending the injection of bile as treatment for COVID-19 — the efficacy of which remains unproven.
In addition to bears, Takebe said animals such as geese and cattle are subject to invasive liver-related procedures that raise welfare concerns. For example, the production of foie gras, a French dish composed of a fattened duck or goose liver, requires force-feeding and intensive housing. The practice has been at the center of numerous animal rights debates and is banned in multiple countries and states worldwide.
To address these concerns, Takebe is taking the “counter-intuitive” approach and translating his research into human liver generation into animals. Through the process of lipid profiling, which measures the levels of each type of cholesterol in the blood, scientists can customize the fat composition to create synthetic foie gras.
He estimated that while the green-light on the clinical use of his liver cell research for humans may still be about 13 years away, the agricultural application could be approved in as little as five years.
Other speakers at the symposium outlined additional methods of species conservation and animal welfare, including various methods for curating fake meat for consumption and a “frozen zoo” engineered to create a self-sustaining population of currently endangered rhinos.
“We are hoping that this could be a very good start for people to merge from the different disciplines,” Takebe said. “I think it would be very important for us to diversify, both scientifically and ethically.”
Typically, the field of stem cell research is dominated by engineers rather than biologists. By discussing issues that involve engineering and biology, as well as manufacturing and environmentalism, Takebe aims to increase scientists’ interest in this area of research.
“[I want to] keep this momentum going,” Takebe said. [I] hope to increase the critical mass of the scientist pool to be able to improve the scientific community overall — with this field in particular.”