X-Message-Number: 15351
Date: Mon, 15 Jan 2001 22:06:03 -0800 (PST)
From: Doug Skrecky <>
Subject: PEG is superior to glycerol for safely dehydrating hearts

Title
  Freezing preservation of the mammalian heart explant. III. Tissue
  dehydration and cryoprotection by polyethylene glycol.
Source
  Journal of Heart & Lung Transplantation.  11(4 Pt 1):619-23, 1992 Jul-Aug.
Abstract
  Isolated rat hearts perfused with hyperosmotic Krebs-Henseleit buffer
  containing 60 mmol/L NaCl lose 10% of their tissue water.
  Perfusion of the rat hearts with Krebs-Henseleit buffer
  containing polyethylene glycol 8000 caused a concentration-dependent
  reduction in tissue water. In a study of the effect of different
  cryoprotectants on cardiac preservation, isolated rat hearts were flushed
  with a cardioplegic solution (CP-14), or CP-14 with either 50 mmol/L glycerol
  (CP-15), or 5% polyethylene glycol (CP-16) and frozen at -1.4 degrees C for 5
  hours. Thawed hearts were reperfused in working mode to assess function.
  There was no recovery in CP-14 hearts. Hearts treated with CP-15 recovered
  39.3% +/- 2.9% (mean +/- SEM) of control cardiac output. CP-16 boosted the
  recovery of cardiac output to 54.4% +/- 5.7% (p less than 0.05 vs CP-15).
  Glycerol significantly reduced tissue ice content; PEG further decreased the
  ice content to 31.7% +/- 0.6%, which was distinctively lower than that in
  CP-14 (44.7% +/- 1.1%) and in CP-15 hearts (34.6% +/- 1.1%). Tissue water
  content of CP-14 and CP-15 hearts was similar (3.83 and 3.87 gm H2O/gm dry
  weight). Polyethylene glycol reduced the tissue water content to 3.24 +/-
  0.04 gm H2O/gm dry (p less than 0.01 vs CP-14 and CP-15 by ANOVA). Thus both
  glycerol and polyethylene glycol offered cryoprotection to the heart explant
  by reducing tissue ice formation. Polyethylene glycol was superior to
  glycerol by dehydrating myocardial tissue and further minimizing freezing
  damage.

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