Internal medicine

Tretinoin

Carcinogenesis

Biology

Gene

Endocrinology

Extracellular matrix

Hepatic stellate cell

Retinoid

Chemistry

Immunology

Lipid droplet

Vitamin

Retinol

Retinoic acid

Cell biology

Cancer research

Biochemistry

Medicine

Immune system

Biochimica et Biophysica Acta (BBA) - Molecular and Cell Biology of Lipids

Vitamin A (retinol) is important for normal growth, vision and reproduction. It has a role in the immune response and the development of metabolic syndrome. Most of the retinol present in the body is stored as retinyl esters within lipid droplets in hepatic stellate cells (HSCs). In case of liver damage, HSCs release large amounts of stored retinol, which is partially converted to retinoic acid (RA). This surge of RA can mediate the immune response and enhance the regeneration of the liver. If the damage persists activated HSCs change into myofibroblast-like cells producing extracellular matrix, which increases the chance of tumorigenesis to occur. RA has been shown to decrease proliferation and metastasis of hepatocellular carcinoma. The levels of RA and RA signaling are influenced by the possibility to esterify retinol towards retinyl esters. This suggests a complex regulation between different retinoids, with an important regulatory role for HSCs.

Retinoids in health and disease: A role for hepatic stellate cells in affecting retinoid levels