The synt hetic retinoids represent a new class of drugs wh ich a re highly effective in t he treatment of a broad spectrum of dermatologic d isease, including cystic acne, psori asis, and cutaneous di sorders of keratinization [1 3]. Moreover, t he use of synthetic retinoids in cancer prevent ion and therapy fo r both cutaneous and in te rna l t umors is potent ially the most signi ficant clini...

Vitamin A (retinol) can be produced in the body by hydrolysis of retinyl esters or reduction of retinal. Liver and eggs, which are good animal sources of vitamin A, contain retinyl esters. Plant sources such as carrots and spinach contain pro-vitamin A carotenoids, which can be cleaved to retinal. Retinal, also called retinaldehyde, is interconvertible with retinol (Fig. 1). Retinal also serves...

Vitamin A (retinol) is an essential vitamin in the daily functioning of human beings that helps regulate cellular differentiation [2] of epithelial tissue. Studies have shown that an excess of vitamin A can affect embryonic development and result in teratogenesis, or the production of birth defects [3] in a developing embryo. Excess intake of vitamin A and retinoids by pregnant women often resu...

The "retinoid revolution" has had considerable impact on research activity in the field of lung development. Postnatal lungs are very sensitive to dietary retinol (R) deprivation. The trachea and the bronchopulmonary tree in R-deficient animals show a striking change in morphology. The columnar epithelium undergoes keratinizing metaplasia, which is reversed when R is supplied. The fetal lung de...

BACKGROUND Retinoic acid has antimitogenic effects on smooth muscle cells. Studies on the systemic circulation suggest that it may reduce vascular thickening. Relationships between retinoids and pulmonary hypertension/pulmonary vascular remodeling, however, have not been explored. Thus, the present study examined retinoid levels in plasma of patients with idiopathic pulmonary arterial hypertens...

Retinoic acid (RA), a derivative of vitamin A, is involved in signal transduction during vertebrate organogenesis. Retinoids through binding to nuclear receptors called RA receptors (RARs) and retinoid X receptors (RXRs) regulate various processes during cardiogenesis. Deregulated retinoid signaling thus has later consequences leading to cardiac malformations. In this review, we will summarize ...

Several in vitro and in vivo studies have examined the positive and negative effects of retinoids (vitamin A analogs) in premalignant and malignant lesions. Retinoids have been used as chemopreventive and anticancer agents because of their pleiotropic regulator function in cell differentiation, growth, proliferation and apoptosis through interaction with two types of nuclear receptors: retinoic...

The key role of vitamin A in embryonal development is reviewed. Special emphasis is given to the physiological action of retinoids, as evident from the retinoid ligand knockout models. Retinoid metabolism in embryonic tissues and teratogenic consequences of retinoid administration at high doses are presented. Physiological and pharmacological actions of retinoids are outlined and explained on t...

Clinical studies suggest that the oral acyclic retinoid Peretinoin may reduce the recurrence of hepatocellular carcinoma (HCC) following surgical ablation of primary tumours. Since hepatitis C virus (HCV) infection is a major cause of HCC, we assessed whether Peretinoin and other retinoids have any effect on HCV infection. For this purpose, we measured the effects of several retinoids on the re...

Despite the effectiveness of the selective estrogen receptor (ER) modulators in preventing ER-positive breast cancer, chemopreventive agents still need to be developed for the prevention of ER-negative breast cancers. The naturally occurring retinoids are promising agents for the prevention of human cancers but are too toxic for long-term chronic use. We previously demonstrated that the chemopr...