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

treatment was found to attenuate inducible nitric oxide synthase (NOS2) activation in
cultured rat cardíac myocytes and microvascular endothelial cells' This indicates that
retinoic acid may play a significant role in the prevention of NOS2-induced myocardial
and coronary inflammation and dysfunction (Grosjean et al. 2001).
A number of synthetic rexinoids (RXR selective retinoids) are found to effect the
post-translational modification of lipoprotein lipase (LPL) in skeletal and cardiac muscle
tissues isolated from diabetic rats. Rexinoid-induced LPL modification in skeletal and
cardiac tissues will result in an increase in plasma triglyceride levels without affecting the
activity of LPL in adipose tissues (Davies et al. 2001). These findings indicate that since
LPL is a gatekeeper enzyme controlling the delivery of fatty acids to tissues, the
decreased LPL activity in muscle tissues will result, in the long run, in a depletion of
lipid stores in heart and muscle, that will in turn lead to improvement in the insulin
sensitivity in muscles (Davies et al. 2001). Retinoic acid also exhibits its effects on the
process of atherosclerosis. A study by Claudel et al. 2001 has shown that administration
of synthetic forms of retinol (rexinoids) to apoprotein E knockout mice was not only able
to reduce the occurrence of atherosclerosis in heart and coronary vessels, but was also
able to cause a reduction in the size of the existing plaques (Claudel et al. 2001). This
mày be achieved though a heterodymeric binding of RXR's with peroxisome
proliferation activator receptor y (PPAR y), which will cause the activation of tissue
lipoprotein lipase (Claudel et al. 2001).
Retinoids are also implicated in the regulation of angiogenesis. A study by
Gaetano et al. (2001) has shown that the administration of the RAR cr specific agonist
was able to induce the production of fibroblast growth factor-Z (FGF-2) in endothelial
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