il\VOLVEMENT OF RETII\OIC ACID II{ - MSpace at the University of ...

cells (Gaetano et ai. ZOot¡. The stimulation of FGF-2 production in endothelial cells will
cause an increase in cell proliferation and differentiation, which can induce angiogenesis
in vivo and in vitro (Gaetano et al. 2001).
Retinoic acid is also considered to play a significant role in the regulation of
ventricular remodeling. De Pavia et ai. (2003) has reported that retinoic acid treatment
of adult 'Wistar rats resulted in the changes in the left ventricular mass and left ventricular
end diastolic diameter (Rupp de Pavia et al. 2003). The administration of retinoic acid
also caused a decrease in the time to peak developed tension and increased the maximum
velocity of isometric re-lengthening in isolated papillary muscle preparation. These
retinoic acid-induced functional changes resulted in the improvement of heart's systolic
and diastolic function (Rupp de Pavia et al. 2003). A number of clinical data has shown
that one of the characteristics of the aging process is a progressive decline in myocardial
function. This is attributed to the changes in cardiac myosin heavy chain (MHC)
composition which undergoes a transition from an o to a B configuration. A study
performed by Long et al. 1999 has shown that this switch is accompanied by a decline in
the RXR y protein and mRNA levels (Long et al. 1999).This indicates that the changes in
the RXR y activity may be connected with the decline in the cardiac function of an aging
heart .
Retinoic acid is also found to play a role in cardiac electrical signal transduction.
Study performed by van Veen et al. (2002) has showri that B MHC-hRAR o transgenic
mice exhibited the significant changes in the heart weight/body weight ratio and have
shown the signs of Q-T interval prolongation (van Veen et al. 2002). This was
accompanied by the ventricular activation delay, increased heterogeneity in conduction
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