From: Brett Paatsch (bpaatsch@bigpond.net.au)
Date: Thu Aug 07 2003 - 04:00:40 MDT
Rafal Smigrodzki <rafal@smigrodzki.org> writes:
> 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.
Very cool :-) I'd say, with respect to cryonics, the peanut just got pushed
slightly forward.
What I'd like to see as a follow up (not having read the original paper) is
the same process applied to say pig hearts (comparable in size to the
human heart) with incremental decreased in temperature and longer period
of the organ being set aside in storage. If we can get hearts to liquid
nitrogen temperature then restore and successfully implant them we won't
exactly have our "Benny the dog" (Vanilla Sky) but we may have a partially
"reanimated" Babe (the pig movie).
Brett
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