Antifreeze Proteins: Novel Applications and Navigation towards Their Clinical Application in Cryobanking

Abstract

Antifreeze proteins (AFPs) or thermal hysteresis (TH) proteins are biomolecular gifts of nature to sustain life in extremely cold environments. This family of peptides, glycopeptides and proteins produced by diverse organisms including bacteria, yeast, insects and fish act by non-colligatively depressing the freezing temperature of the water below its melting point in a process termed thermal hysteresis which is then responsible for ice crystal equilibrium and inhibition of ice recrystallisation; the major cause of cell dehydration, membrane rupture and subsequent cryodamage. Scientists on the other hand have been exploring various substances as cryoprotectants. Some of the cryoprotectants in use include trehalose, dimethyl sulfoxide (DMSO), ethylene glycol (EG), sucrose, propylene glycol (PG) and glycerol but their extensive application is limited mostly by toxicity, thus fueling the quest for better cryoprotectants. Hence, extracting or synthesizing antifreeze protein and testing their cryoprotective activity has become a popular topic among researchers. Research concerning AFPs encompasses lots of effort ranging from understanding their sources and mechanism of action, extraction and purification/synthesis to structural elucidation with the aim of achieving better outcomes in cryopreservation. This review explores the potential clinical application of AFPs in the cryopreservation of different cells, tissues and organs. Here, we discuss novel approaches, identify research gaps and propose future research directions in the application of AFPs based on recent studies with the aim of achieving successful clinical and commercial use of AFPs in the future.

Natural Cryoprotective and Cytoprotective Agents in Cryopreservation: A Focus on Melatonin

“…Due to these properties, these agents have gained increasing attention in the last several years. These include AFPs that hold great potential for an application in cryobanking [ 29 ]. Although these proteins and peptides can have immunogenic effects and are difficult to produce, they represent an alternative to synthetic CPAs.…”

“…During evolution, living organisms have developed strategies to survive in cold environments, including antifreeze proteins (AFPs) and ice nucleation agents (INAs) [ 29 ].…”

“…Natural CPAs have become a popular subject among researchers that have attempted to find an alternative to synthetic CPAs [ 28 , 29 , 30 ]. However, much less is known about their mechanism of action and efficacy in cryopreservation.…”

Cryopreservation of Animals and Cryonics: Current Technical Progress, Difficulties and Possible Research Directions

“…Vitrification is the preferred cooling method in cryonics as the body is preserved in a stable glassy state ( 8 , 67 ) but achieving this requires high CPA concentrations which can be damaging and toxic. As the future of cryonics is reanimation, a significant amount of research is currently focused on developing safer and effective CPA options including antifreeze proteins (AFPs) ( 68 ), trehalose ( 69 ), DP6 ( 70 ), nanotechnology engineered cryoprotectants ( 71 ), neutral amino acids ( 6 ). A major milestone was recorded in 2007 when major cryonics organizations claimed to have successfully vitrified the brain without ice formation ( 9 ), still post-thaw recovery not being promised drove the award-winning research of G. Fahy and R. McIntyre in 2015 ( 72 ).…”

Application of Nanoparticles and Melatonin for Cryopreservation of Gametes and Embryos

“…Preliminary research examined antifreeze protein (AFP) that helps organisms survive in sub-zero temperatures [ 153 , 154 ]. This protein lowers the freezing point of the water surrounding the cell membrane to below the melting point, allowing organisms to survive in low temperatures [ 155 ]. AFPs interact with ice surfaces and suppress ice crystallization until the freezing temperature.…”