Researchers from the Université du Québec à Montréal have hit upon a new approach to cryopreservation of cells, a development which could have clinical applications in the treatment of diseases of the liver and pancreas and beyond.
The study published in this month’s edition of the journal Biotechnology and Bioengineering showed that protein extracts from winter wheat can serve as a cryoprotectant agent for the freezing and thawing of tissue cells.
This may prove pivotal, as up until now liver and pancreatic cells have been difficult to maintain long term via cryopreservation.
Cryopreservation is the process of preserving materials by freezing – plant seeds, embryos, tissue samples and semen are some of the materials that have been successfully cryopreserved to date.
For cell cryopreservation, the process requires the use of an agent – a cryoprotectant – to prevent ice crystals from forming within the cell during the freezing process.
The problem is that the most often used protectants, dimethyl sulfoxide (DMSO) and glycerol, have been shown to be both toxic and ineffective for the preservation of cells of the liver and pancreas.
But researchers found that when injected with the wheat protein, cells maintained their integrity during freezing and thawing. “The overall quality of these cell types was equivalent or improved compared to cells that were cryopreserved with DMSO,” say the study’s authors.
Winter wheat are strains of wheat that are planted in the autumn to germinate and develop into young plants. They remain in the vegetative phase during the winter and resume growth in early spring.
Cryopreservation is becoming a key piece of the puzzle for cell transplantation, including hepatocyte (liver cell) transplantation.
Acute diseases of the liver are especially problematic because there are few treatment options available, aside from whole or partial organ transplantation.
One that is gaining ground, however, is hepatocyte transplantation, where liver cells are injected directly into the liver or spleen, with the hope that the new cells integrate into the host liver and reverse the course of hepatic failure.
The Canadian Liver Foundation says one in 10 Canadians have some form of liver disease and that the death rate from liver disease has risen nearly 30% over the past decade.
Over 400 liver transplants are performed in Canada every year, with an average success rate of 85 to 90%.
Yet there are still about 400 people at any given time on the waiting list for a new liver, and that’s where hepatocyte transplantation offers another option. But just as for organ transplants, we do not have a sufficient source of fresh human hepatocytes. (Which are primarily obtained via rejected transplant livers.)
Cryopreservation may be able to fill that void, as it has the potential to create a new source of viable cells for transplant.
“There is increasing demand for cryopreserved cells such as liver and pancreatic cells for clinical applications,” the study’s authors say.
All types of liver disease are on currently on the rise in Canada. Top of the list are viral hepatitis, alcoholic liver disease, fatty liver disease, hepatocellular carcinoma and acute liver failure. Worldwide, viral hepatitis is the most common form of liver disease.