X-Message-Number: 13248 Date: Sat, 12 Feb 2000 14:10:43 -0800 (PST) From: Doug Skrecky <> Subject: cardiac preservation with polyethylene glycol (long) <1-4> <1> Authors Gutierrez-Carretero E. Bello-Puentes R. Borrego-Dominguez JM. Hernandez-Fernandez A. Munoz-Garcia J. Ordonez-Fernandez A. Institution Virgen del Rocio Hospital, Seville, Spain. Title Alteration in diastolic function following cardiac cryopreservation at subzero temperatures. Source Journal of Heart & Lung Transplantation. 18(4):372-5, 1999 Apr. Abstract BACKGROUND: We have studied the alterations produced in the diastolic function of the left ventricle after applying a protocol of cryopreservation at subzero temperatures. METHODS: Isolated rabbit hearts and 5% polyethylene glycol (PM 4000) as the cryoprotective agent were used for the study. RESULTS-CONCLUSIONS: Following cryopreservation we found a statistically significant increase in systolic function. However, the diastolic function shows worsening, with a statistically significant increase (p < 0.05) in mean stiffness, decrease in differential stiffness, (p < 0.05) and upward and leftward displacement of the diastolic pressure-volume curve. <2> Authors Wicomb WN. Hill DJ. Collins GM. Institution Research Institute, California Pacific Medical Center, San Francisco 94115. Title Twenty-four-hour ice storage of rabbit heart. Source Journal of Heart & Lung Transplantation. 13(5):891-4, 1994 Sep-Oct. Abstract Although cardioplegia is limited to 4 hours of ice storage, University of Wisconsin solution has successfully extended this period to approximately 12 hours. In this study we have substituted polyethylene glycol for hydroxyethyl starch in a simplified University of Wisconsin solution (Cardiosol). Rabbit hearts were ice stored for 24 hours at 0 degrees C in either University of Wisconsin solution or Cardiosol (containing either 5% or 10% polyethylene glycol). Fresh control hearts were tested immediately after cardiectomy. Function was evaluated in an in vitro working heart model for 1 hour with aortic afterload at 100 cm H2O. Total cardiac output or the proportion of hearts reaching 100 cm H2O were compared. Hearts stored in University of Wisconsin solution for 24 hours functioned at 6% of control levels at 15 minutes of observation. None reached 100 cm H2O or deteriorated further with time (p < 0.05). By contrast, hearts stored in 5% Cardiosol showed progressive recovery during the 1-hour observation. Of the 13 hearts, 11 reached 100 cm H2O with a mean cardiac output of 51% of the control value. Increasing the concentration of polyethylene glycol to 10% improved cardiac output at all observation times, reaching 80% of control heart performance at 1 hour (control > 10% > 5% > University of Wisconsin solution [p < 0.05]). We concluded that 10% polyethylene glycol significantly improved 24-hour ice storage and, hence, viability to a functional level that matched our previously reported microperfusion results. <3> Authors Banker MC. Layne JR Jr. Hicks GL Jr. Wang T. Institution Department of Surgery, University of Rochester, N.Y. 14642. 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. <4> Authors Banker MC. Layne JR Jr. Hicks GL Jr. Wang TC. Institution Department of Surgery, University of Rochester, New York 14642. Title Freezing preservation of the mammalian cardiac explant. II. Comparing the protective effect of glycerol and polyethylene glycol. Source Cryobiology. 29(1):87-94, 1992 Feb. Abstract We compared the cryoprotective ability of glycerol and polyethylene glycol (PEG) during freezing. Isolated rat hearts were flushed with one of three cardioplegic solutions (CP-14, CP-15, and CP-16), frozen at -1.4 degrees C, and reperfused after thawing to assess function. After 3 h freezing, cardiac output (CO) in CP-14-flushed hearts recovered to 58.1% of control. CP-16 (CP-14 with 5% PEG) improved CO to 77.5%. Five hours of freezing abolished recovery in CP-14 hearts, but CP-15 (CP-14 with 50 mM glycerol) and CP-16 hearts produced 40.0 and 49.0% CO, respectively. With 6 h freezing, CP-15 hearts did not recover, whereas CP-16 hearts recovered 37.5% CO. In CP-14 hearts frozen for 3 h, 37.4% of the tissue water was ice that increased to 44.7% with 5 h freezing. CP-15 and CP-16 hearts had 34.4 and 30.9% tissue ice, respectively, after 5 h freezing. Tissue water contents in CP-14 and CP-15 hearts (3.83 to 3.96 g H2O/g dry) were 14 to 24% higher than that in CP-16 hearts. Six hours of freezing elevated AMP and ADP contents and reduced ATP levels in CP-15 and CP-16 hearts. Total adenine nucleotide (TAN) content of CP-15 hearts was 72% of control, while that of CP-16 hearts was normal. In conclusion, both glycerol and PEG offered cryoprotection by reducing tissue ice formation. PEG was superior by reducing tissue ice content further via dehydration and by better preserving TAN content. Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=13248