X-Message-Number: 13372
Date: Tue, 07 Mar 2000 17:46:33 -0500
From: Jan Coetzee <>
Subject: cryopreservation improves functions of islet cells

It would be nice if this was true for some brain cells.
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Transplantation 1999 Sep 15;68(5):655-62
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                  Effects of cryopreservation on in vitro and in vivo
                  long-term function of human islets.

                  Piemonti L, Bertuzzi F, Nano R, Leone BE, Socci C,
Pozza G, Di
                  Carlo V

                  Department of Surgery, Istituto Scientifico San
Raffaele, Universita degli
                  Studi di Milano, Milan, Italy. 

                  BACKGROUND: The possibility of performing
transplantation several
                  days after explant seems to be a peculiarity of islet
grafts, and the
                  opportunity to cryopreserve human islets may permit an
indefinite period
                  for modulating the recipient immune system. The aim of
the present study
                  was the evaluation of in vitro and in vivo functional
properties of
                  cryopreserved human islets. METHODS: We used six
consecutive human
                  islet preparations not suitable for an immediate
transplantation in diabetic
                  patients because the limited islet mass separated. The
in vitro function of
                  cryo and fresh islets was studied by determination of
insulin and glucagon
                  secretion in response to such classical stimuli as
glucose (16.7 mM),
                  glucose (16.7 mM) + 3-isobutyl-1-methylxanthine (0.1
mM), arginine (10
                  mM), and tolbutamide (100 microM). In vivo islet
function was assessed
                  through intravenous glucose tolerance tests performed
at 15, 30, 60, and
                  90 days after transplantation of 1000 hand-picked
fresh or cryopreserved
                  islets in nude mice. RESULTS: Basal secretion of true
insulin was
                  significantly higher in cryopreserved islets than in
fresh ones. The
                  response of cryopreserved islets to arginine and
glucose +
                  isobutyl-1-methylxanthine seemed partially impaired.
Proinsulin-like
                  molecule secretion seemed higher in cryopreserved than
in fresh islets in
                  response to all secretagogues used, and the difference
was statistically
                  significant for arginine. The capacity of human
cryopreserved islets to
                  maintain a correct metabolic control in diabetic nude
mice was
                  progressively lost in 3 months. CONCLUSIONS: These
findings showed
                  that cryopreservation affects the function of isolated
human islets,

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