From: Rafal Smigrodzki (rafal@smigrodzki.org)
Date: Wed Aug 06 2003 - 17:25:53 MDT
I thought this might of interest to some list members:
Eur J Cardiothorac Surg. 2003 Aug;24(2):292-7. Related Articles, Links
Preservation of myocyte structure and mitochondrial integrity in subzero
cryopreservation of mammalian hearts for transplantation using antifreeze
proteins-an electron microscopy study.
Amir G, Rubinsky B, Kassif Y, Horowitz L, Smolinsky AK, Lavee J.
Department of Cardiac Surgery, Heart Transplantation Unit, Sheba Medical
Center, Tel Hashomer, 52621, Ramat Gan, Israel
OBJECTIVE: Freeze tolerant fish and insects in nature are able to survive
subzero temperatures by noncolligatively lowering the freezing temperature
of their body fluids using a family of thermal hysteresis proteins
(antifreeze proteins, AFPs) specific for each species. Past efforts to
cryopreserve mammalian hearts using these proteins were unsuccessful. We
report the first successful subzero cryopreservation of rat hearts using
fish derived antifreeze proteins with preservation of myocyte structure.
METHODS: Heterotopic heart transplantations were performed in isoimmunic
Sprague Dawley rats. Donors' hearts were arrested using University of
Wisconsin (UW) solution and preserved in UW solution containing AFP I (six
experiments) or AFP III (six experiments) at concentrations of 15-20 mg/cc
for 2-6 h at subzero temperatures ranging from -1.1 to -1.3 degrees C. Four
control experiments were performed by preserving harvested hearts in UW
solution alone at -1.3 degrees C for 6 h. In all experiments ice was added
in the solution for crystallization. Heterotopic transplantations were
performed in the abdomen of the recipient rats. Viability was visually
assessed and graded on a scale of 1 (poor contraction) to 6 (excellent
contraction). The hearts were then fixed in vivo and processed for electron
microscopy study. RESULTS: All hearts preserved at subzero temperatures
using AFP I or AFP III survived displaying viability scores of 4-6 1 h after
transplantation. Three of the four control hearts that were preserved
at -1.3 degrees C without the protective effect of AFP froze and died upon
reperfusion. Electron microscopy study of hearts preserved with AFP
demonstrated preservation of myocyte structure and mitochondrial
integrity.CONCLUSION: Subzero cryopreservation of mammalian hearts for
transplantation using AFP I or AFP III is feasible with preservation of
myocyte structure and mitochondrial integrity.
### I wonder how low can one go with the temperature, as you increase the
concentration of the AFP. 15 mg/cc is pretty low as soluble protein
concentrations go.
Rafal
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