Institution
Department of Medicine, University of Auckland, New Zealand.
d.ormrod@auckland.ac.nz
Title
Dietary chitosan inhibits hypercholesterolaemia and
atherogenesis in the apolipoprotein E-deficient mouse model of
atherosclerosis.
Source
Atherosclerosis. 138(2):329-34, 1998 Jun.
Abstract
Chitosan, the deacetylated form of chitin, is extracted from
the shells of crustaceans. The strong positive charge carried by the
chitosan molecule causes it to bind negatively charged
substrates such as lipids. Orally administered chitosan
binds fat in the intestine, blocking absorption, and has been shown to lower
blood cholesterol in animals and humans. As a result it has been proposed
that dietary supplementation with chitosan may inhibit the
formation of atherosclerotic plaque. We have tested this hypothesis using the
apolipoprotein E-deficient mouse model of atherosclerosis. This
hypercholesterolaemic animal develops atherosclerosis without the need for
dietary or surgical intervention. The apolipoprotein E-deficient mouse
therefore provides an ideal model in which to study the effects of dietary
chitosan on both blood cholesterol and atherosclerosis.
Animals were fed for 20 weeks on a diet containing 5%
chitosan or on a control diet. Blood cholesterol levels were
significantly lower in the chitosan fed animals throughout
the study, and at 20 weeks were 64% of control levels. When the area of
aortic plaque in the two groups was compared a highly significant inhibition
of atherogenesis, in both the whole aorta and the aortic arch, was observed
in the chitosan fed animals--42 and 50%, respectively. Body
growth was significantly greater in the chitosan fed
animals. This study is the first to show a direct correlation between
lowering of serum cholesterol with chitosan and inhibition
of atherogenesis, and suggests that the agent could be used to inhibit the
development of atherosclerosis in individuals with hypercholesterolaemia.