X-Message-Number: 15391 Date: Fri, 19 Jan 2001 10:12:38 -0800 (PST) From: Doug Skrecky <> Subject: alas! 40% ethylene glycol is toxic to arteries [Note by poster: IMHO organ dehydration by relatively nontoxic, non-penetrating cryoprotectants such as PEG, or glucose might be the best first step towards organ vitrification. More toxic, and concentrated penetrating cryoprotectants could then be used for a shorter period of time, as a second final step. The idea here is to maximize dehydration, and minimize tissue uptake of toxic cryoprotectants during vitrification procedures.] ---------- Forwarded message ---------- Title The effect of cooling rate and temperature on the toxicity of ethylene glycol in the rabbit internal carotid artery. Source Cryobiology. 33(4):423-9, 1996 Aug. Abstract The smooth muscle and vascular endothelium of small elastic arteries (the rabbit common carotid artery) are injured by exposure to 40% ethylene glycol (EG) at 4 degrees C, and additional damage occurs when the arteries are cooled without freezing to -20 degrees C. This paper reports attempts to reduce this injury by altering the cooling rate and temperature of exposure to the cryoprotectant. Very slow cooling (0.1 degree C/min) removed all residual smooth muscle and endothelial function when assessed in vitro after rewarming and removal of the cryoprotectant. Very rapid cooling to -20 degrees C also increased the injury, both to the endothelium and to the smooth muscle. Reducing the temperature of exposure to 40% EG from +4 degrees C to -20 degrees C had no beneficial effect on the smooth muscle but enabled the vascular endothelium to retain some functional activity. These data suggest that the mechanism responsible may be related to the physical properties of ethylene glycol rather than to a biochemical interaction with metabolic processes, and that it is a mechanism which is highly specific for the cell types involved. It also underlines the difficulties involved in the successful cryopreservation of complex tissues and organs. Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=15391