X-Message-Number: 15245
Date: Wed, 3 Jan 2001 11:35:01 -0800 (PST)
From: Doug Skrecky <>
Subject: aspartate/glutamate combats cardiac anoxia

Title
  Cardiac function and
  glycogen content after twenty-four-hour preservation with
  various metabolic substrates.
Source
  Journal of Heart & Lung Transplantation.  17(3):299-305, 1998 Mar.
Abstract
  BACKGROUND: Previous work has suggested that recovery of
  cardiac function after long preservation
  periods is improved if a suitable exogenous substrate is provided. However,
  interpretation of existing data on the benefit of added substrate is
  complicated by differing preservation media and protocols studied, as well as
  differing models used to evaluate postpreservation recovery. These
  experiments were designed to evaluate glucose, pyruvate, aspartate, and
  glutamate as exogenous substrates for prolonged perfusion preservation of
  hearts with a rat heart model preserved with crystalloid medium and with
  function quantified in an isolated working heart
  preparation. METHODS: Cardiac function (n =
  5/group) and tissue glycogen content (n = 5/group) were
  measured in fresh control rat hearts and four groups of hearts preserved for
  24 hours in an extracellular-type cardioplegic medium containing 11 mmol/L
  glucose and either 20 mmol/L sodium aspartate, 20 mmol/L sodium glutamate, 20
  mmol/L sodium pyruvate, or no other substrate. Postpreservation
  cardiac function was measured in an
  isolated working rat heart preparation for a 4-hour reperfusion period.
  Exogenous substrate consumption during preservation and tissue
  glycogen content at the end of preservation were measured
  with spectrophotometric assays. RESULTS: All hearts in the aspartate- and
  glutamate-preserved groups functioned for the full 4-hour
  period with stroke work that was 50% to 60% of control. Hearts preserved with
  only glucose substrate had inconsistent recovery: two of five hearts in that
  group did not recover, whereas three recovered similar to the aspartate and
  glutamate groups. None of the pyruvate-preserved hearts recovered contractile
  function. There was no association between postpreservation
  tissue glycogen content and extent of
  cardiac function recovery. CONCLUSION:
  Aspartate or glutamate plus glucose was the best substrate mixture among
  those tested for long-term perfusion preservation of hearts. These amino
  acids offer advantages over pyruvate because they produced better recovery of
  the hearts and because they are chemically more stable than pyruvate.
  Aspartate or glutamate plus glucose also produced better postpreservation
  function compared with glucose alone.

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