X-Message-Number: 32437
Date: Sat, 27 Feb 2010 18:01:45 -0800 (PST)
Subject: Physical and biological aspects of renal vitrification.

[Partial vitrification is all that is available as yet, due to
cryoprotectant toxicity limiting the concentration of solutes. This is a
work in progress...]

Organogenesis. 2009 Jul;5(3):167-75.
Physical and biological aspects of renal vitrification.
Fahy GM, Wowk B, Pagotan R, Chang A, Phan J, Thomson B, Phan L.
21 Century Medicine, Inc.; Fontana, CA USA.

Cryopreservation would potentially very much facilitate the inventory control 
and distribution of laboratory-produced organs and tissues. Although simple 
freezing methods are effective for many simple tissues, bioartificial organs and
complex tissue constructs may be unacceptably altered by ice formation and 
dissolution. Vitrification, in which the liquids in a living system are 
converted into the glassy state at low temperatures, provides a potential 
alternative to freezing that can in principle avoid ice formation altogether. 
The present report provides a brief overview of the problem of renal 
vitrification. We report here the detailed case history of a rabbit kidney that 
survived vitrification and subsequent transplantation, a case that demonstrates 
both the fundamental feasibility of complex system vitrification and the 
obstacles that must still be overcome, of which the chief one in the case of the
kidney is adequate distribution of cryoprotectant to the renal medulla. 
Medullary equilibration can be monitored by monitoring urine concentrations of 
cryoprotectant, and urine flow rate correlates with vitrification solution 
viscosity and the speed of equilibration. By taking these factors into account 
and by using higher perfusion pressures as per the case of the kidney that 
survived vitrification, it is becoming possible to design protocols for 
equilibrating kidneys that protect against both devitrification and excessive 
cryoprotectant toxicity.
PMID: 20046680 [PubMed - in process]

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