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Aging and CR affect the functions of various tissues within
our bodies, but
how does the expression of these genes become affected in
these various
tissues? It seems that some genes have altered expression
during aging and
CR and some do not. Sometimes the changes seen in gene
expression are in
different directions in different tissues. CR may affect
different tissues
differentially, it seems. We seem to know that the
reduction in overall
body mass that occurs with CR discriminates in the relative
amount of
reduction for each organ system within the body, and this
new paper
indicates the degree of differentiation in the potential
functions within
the organs/tissues as well.

Fu C, Hickey M, Morrison M, McCarter R, Han ES.
Tissue specific and non-specific changes in gene expression
by aging and by
early stage CR.
Mech Ageing Dev. 2006 Nov 6;
PMID: 17092546

Aging alters the expression of a variety of genes. Calorie
restriction (CR),
which extends life span in laboratory rodents, also changes
gene expression.
This study investigated changes in gene expression across
three different
tissues from the same mouse to examine how aging and early
stage CR
influence gene expression in different tissues of an
organism. Expression
profiling of heart, liver, and hypothalamus tissues was done
in young (4-6
months) ad libitum fed (AL), young CR (2.5-4.5 months of
CR), and old (26-28
months) AL male C57BL/6 mice. Aging significantly altered
the expressions of
309, 1819, and 1085 genes in heart, liver, and hypothalamus
tissues,
respectively. In nine genes, aging altered expression across
all three
tissues although the regulation directions did not agree
across all three
tissues for some genes. Early stage CR in young mice
significantly changed
the expressions of 192, 839, and 100 genes in heart, liver,
and hypothalamus
tissues, respectively, and seven genes altered expression
across all three
tissues; three were up regulated and four were down
regulated. The results
of Gene Ontology (GO) Biological Process analysis indicated
up regulation of
antigen processing/presentation genes by aging and down
regulation of stress
response genes by early stage CR in all three tissues. The
comparison of the
results of aging and short term CR studies showed there were
389 genes, 18
GO biological processes, and 20 GO molecular functions in
common.