H Serrar1, P Haddad. 1. Groupe de Recherche en Transport Membranaire et Département de Pharmacologie, Université de Montréal, Québec, Canada.
Abstract
BACKGROUND & AIMS: Liver graft dysfunction is related to hypothermic preservation and may implicate altered cell volume homeostasis. The aim of this study was to evaluate how cold preservation and rewarming affect hepatocellular volume regulation and concentrative amino acid uptake. METHODS: Rat hepatocytes suspended for variable times in cold preservation solution were subsequently cultured at 37 degrees C. Cell viability was assessed by trypan blue exclusion. Cell volume was measured by videoplanimetric analysis of microscopic images. Amino acid uptake was assessed by measuring Na+-dependent cell swelling. RESULTS: Cell viability decreased as a function of cold storage time even as early as 4 hours. Upon hypotonic stress, cells swelled similarly irrespective of preservation time. However, the rate of subsequent regulatory volume decrease diminished significantly with increasing preservation time. Upon return to isotonic perfusate, cells shrunk to a similar extent, but the rate of regulatory volume increase was halved by cold storage beyond 24 hours. The rate of proline-induced cell swelling was diminished greatly after cold storage, unlike that induced by aminoisobutyric acid and glutamine. CONCLUSIONS: Hepatocellular volume regulatory mechanisms and concentrative proline uptake are significantly impaired after cold preservation and rewarming, unlike alpha-aminoisobutyric acid and glutamine uptake. This may favor chronic cell swelling after transplantation and participate in liver graft dysfunction.
BACKGROUND & AIMS:Liver graft dysfunction is related to hypothermic preservation and may implicate altered cell volume homeostasis. The aim of this study was to evaluate how cold preservation and rewarming affect hepatocellular volume regulation and concentrative amino acid uptake. METHODS:Rat hepatocytes suspended for variable times in cold preservation solution were subsequently cultured at 37 degrees C. Cell viability was assessed by trypan blue exclusion. Cell volume was measured by videoplanimetric analysis of microscopic images. Amino acid uptake was assessed by measuring Na+-dependent cell swelling. RESULTS: Cell viability decreased as a function of cold storage time even as early as 4 hours. Upon hypotonic stress, cells swelled similarly irrespective of preservation time. However, the rate of subsequent regulatory volume decrease diminished significantly with increasing preservation time. Upon return to isotonic perfusate, cells shrunk to a similar extent, but the rate of regulatory volume increase was halved by cold storage beyond 24 hours. The rate of proline-induced cell swelling was diminished greatly after cold storage, unlike that induced by aminoisobutyric acid and glutamine. CONCLUSIONS: Hepatocellular volume regulatory mechanisms and concentrative proline uptake are significantly impaired after cold preservation and rewarming, unlike alpha-aminoisobutyric acid and glutamine uptake. This may favor chronic cell swelling after transplantation and participate in liver graft dysfunction.