For many heart, kidney, and liver patients, a transplant is the only viable solution to keep them alive. But the odds of finding a compatible donor are pretty slim: about one in ten, according to the World Health Organization.
Doctors would have a much easier time saving the other 90 percent of transplant candidates if they could find what they need in an organ bank.
Unfortunately, there is currently no way to preserve organs long-term. But thanks to research at Hebrew University, there soon may be.
“The ability to freeze organs and to then thaw them without causing damage to the organ itself would be revolutionary in terms of our chances to save lives,” according Prof. Ido Braslavsky of the Hebrew University Institute of Biochemistry, Food Science and Nutrition at the Robert H. Smith Faculty of Agriculture, Food and Environment.
“Perfecting cryopreservation – the process of preserving cells, tissues and organs in sub-zero temperatures – would enable long-term banking of tissues and organs and efficient matching between donor and patient, eventually saving lives of millions of people around the world,” said Braslavsky.
The research he and his team are doing on ice-binding proteins – the same proteins that allow fish, animals, and even bacteria to survive in the Antarctic – could solve the problem, said Braslavsky.
Today, the best doctors can do is store organs in cool temperatures – in a portable refrigerator, essentially – and transport them to patients in need, whether across town or across the country. Across the world is iffier; after about 12 hours, hearts and livers tend to deteriorate to the point where they are no longer usable. Kidneys last a bit longer – about 30 hours – but even those need to be transplanted quickly in order to ensure their effectiveness.
Freezing organs doesn’t work; when the water molecules in the organs are frozen, they expand, damaging the delicate cells and compromising the organ’s ability to work in the body. That is why, said Braslavsky, organs such as hearts, kidneys, livers, lungs and intestines are kept in coolers but not in freezers.
If they could be frozen, however, many more lives could be saved. as doctors could get the organs they need.
Braslavsky, one of the world’s top researchers in the field of cryopreservation, has for years studied antifreeze proteins, a type of ice-binding protein that helps organisms to resist or withstand freezing both in sea and on land.
He and his Hebrew University colleagues, including Dr. Maya Bar Dolev, Dr. Liat Bahari, Dr. Amir Bein, Dr. Ran Drori, Dr. Victor Yeshunsky and others, and in collaboration with Prof. Peter Davies from Queens University in Canada, study the effects of the proteins that were discovered some 50 years ago in Antarctic fish, and are now known to exist in cold-resistant fish, plants, insects and microorganisms.
“We investigate the interaction of ice-binding proteins with ice crystals,” said Braslavsky. “Since we are working at temperatures of sub-zero Celsius degrees and we need high accuracy of working temperature, we designed a specialized microscope with a stage cooler that allows a millidegree-level control of temperature and also freezing. Using fluorescent illumination, we can see where the proteins, which are tagged with fluorescent dyes, are located. With these devices, we can follow ice crystals as they grow and melt in the presence of ice-binding proteins.”
With the proteins, creatures living in sub-zero environments are able to avoid the freezing of their own organs, the research shows. Braslavsky and his students showed that proteins adhere to ice via “irreversible binding,” creating a buffer between the ice and the cells for the duration of the “cold snap,” thus preventing the ice from expanding and damaging the cells.
The study, said Braslavsky, explained how ice-binding proteins stop ice growth, a major mystery that puzzled scientists in the field for decades. This finding, published in Langmuir and RSC Advances in 2015, could be crucial for the use of these proteins as cryoprotectants, said Hebrew University.
With continued research, the team hopes to be able to duplicate the process mechanically. The next step is to expand the research, studying more creatures in order to understand the techniques used to prevent freezing, and to try and find ways to do the same in the lab, the team said.
The findings could also revolutionize the frozen food business.
“Ice growth also poses a major problem in frozen food,” says Braslavsky, who also works with his team on the implementation of ice-binding proteins into food. “Many of use are familiar with ice cream that has lost its texture in home freezers, or meat that has lost a lot of its liquids and doesn’t look or taste fresh after thawing. Ice-binding proteins may allow the control of ice in frozen food and the developments of new frozen treats. Some food manufacturers have already started using ice-binding proteins in their products.”
But ice cream aside, the team is focused on its life-saving mission: Figuring out a way to successfully deep-freeze human organs without damaging them. Research in cryopreservation has been an important goal of the Organ Preservation Alliance (OPA), an American NGO established in 2014. The organization aims to accelerate and coordinate research towards banking of human organs, and it says that for the first time, this goal is within reach.
Braslavsky’s research is supported by the European Research Council (ERC), the European Union’s Seventh Framework Programme (FP7), and the Israel Science Foundation (ISF).
Braslavsky’s research comes as the scientific world has begun to understand the need for organ banks. Last year, the first global Organ Banking Summit met in California, bringing world-leading scientists, investors and policy-makers together to “stop biological time” and transform transplantation. It followed an announcement by the US Department of Defense of the first-ever government grants targeted at organ banking.
While the race is on, Braslavsky is hopeful that the cryopreservation research is on the doorstep of success. “Recent developments in cryobiology methodologies and the use of materials with specific interaction with ice crystals such as ice-binding proteins open the possibility for significant advancement in cells and organs cryopreservation,” he added.