Abstract
High levels of penetrating cryoprotectants (CPAs) can eliminate ice formation during cryopreservation of cells, tissues, and organs to cryogenic temperatures. But CPAs become increasingly toxic as concentration increases. Many strategies have been attempted to overcome the problem of eliminating ice while minimizing toxicity, such as attempting to optimize cooling and warming rates, or attempting to optimize time of adding individual CPAs during cooling. Because strategies currently used are not adequate, CPA toxicity remains the greatest obstacle to cryopreservation. CPA toxicity stands in the way of cryogenic cryopreservation of human organs, a procedure that has the potential to save many lives. This review attempts to describe what is known about CPA toxicity, theories of CPA toxicity, and strategies to reduce CPA toxicity. Critical analysis and suggestions are also included.
Highlights
The availability of transplantable organs could considerably postpone 30% of all deaths in the United States
Cryopreservation with propylene glycol (PG) resulted in higher survival than with ethylene glycol (EG) due to greater permeability; but developmental competence of oocytes that survived cryopreservation was greater for EG, suggesting that PG is more toxic.[95]
Using survival to hatching as the toxicity assay for flounder embryos exposed to CPAs for 60 min at-15°C resulted in the following order of CPA toxicities, with EG being the most toxic: EG > glycerol > DMSO > METH > PG.[96]
Summary
The availability of transplantable organs could considerably postpone 30% of all deaths in the United States. Cryopreservation of spermatozoa by GLY was a major breakthrough for cryobiology.[18] some injuries are evident.[19] Systemically, 10 mL of 50% GLY per kilogram induces renal failure in rats through inflammation, oxidative stress, and apoptosis.[20] All of these processes are facilitated by caspases.[21] GLY depletes reduced glutathione in the kidney, leading to oxidative stress.[22] In stallion spermatozoa, GLY in concentrations over 1.5% polymerizes the actin cytoskeleton, a phenomenon unrelated to osmolality.[23] Freezing human sperm with 15% GLY is likely to damage sperm morphology, mitochondria, and viability, but reduction in motility was shown to correlate with reduction in mitochondrial function.[24] GLY is reportedly much more toxic than other CPAs for flounder embryos[25] and Escherichia coli bacteria.[26]. GLY, DMSO, PG, and BD caused corneal endothelial cell loss after exposure for 10–15 min at 0–4°C at concentrations insufficient to vitrify.[73]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
