Vitamin A-storing cell system (stellate cell system) and biodiversity

Abstract

Hepatic stellate cells (HSCs) exist in the space between parenchymal cells and sinusoidal endothelial cells, and store 50-80% of vitamin A in the whole body as retinyl palmitate in lipid droplets in the cytoplasm. HSCs play pivotal roles in regulation of vitamin A homeostasis. The top predators in the Arctic possessed about 10-20 times more vitamin A than all other arctic animals studied as well as their genetically related continental top predators. The values are also high compared to normal human and experimental animals such as mice and rats. This massive amount of hepatic vitamin A was located in large lipid droplets in HSCs. The development of such an efficient vitamin A-storing mechanism in HSCs may have contributed to the survival of top predators in the extreme environment of the Arctic. HSCs play pivotal roles in maintenance of food web, food chain, biodiversity, and eventually ecology of the Arctic.