Human vitamin A (VA) ELISA Kit

Vitamins are essential micronutrients for human growth and development and can be categorized as water-soluble and fat-soluble. Water-soluble vitamins are consumed in the diet, but excess vitamins are excreted from the body, and fat-soluble vitamins are stored in the body's adipose tissue and liver. Vitamin A (VA) is a fat-soluble vitamin that can be categorized into two forms, one being retinoids, which include retinol, retinaldehyde, and retinyl esters. The other form of vitamin A is carotenoids, which are converted from plants into a source of vitamin A. During digestion, vitamin A is absorbed in the intestines through enterocytes before entering the lymphatic circulation. Hepatic stellate cells in the liver store vitamin A in the form of retinyl palmitate. The molecular structure of vitamin A consists of a complex structure containing 20 carbons, a methylcyclohexane ring, a hydroxyl group (retinol), an aldehyde group (retinaldehyde), and a carboxyl group (retinoic acid). The vitamin A precursors retinol, retinoic acid and retinaldehyde derived from animal sources are regarded as retinoids.

Figure 1. Structure and function of vitamin A
(Source: Chen G, et al. 2023)

VA is useful for vision, embryonic cell growth and development, immune system and epithelial cell support. It is also considered an important antioxidant that contributes to a variety of health purposes. In the immune system, VA is involved in innate immunity, cellular immunity and humoral antibody responses. Vitamin A plays a role in the response of antibodies to infections in the body, retinoic acid helps to increase the level of natural killer cells, which have anti-tumor and anti-viral effects in the body, and it can help to increase phagocytosis by macrophages and increase interleukin-1 and other cytokines that act as mediators of inflammation.

Vitamin A deficiency in the body affects vision and can cause dry eye and night blindness. VA deficiency also causes drying of the epithelial cells of the gastrointestinal, respiratory, and genitourinary tracts, which reduces the ability of the cells to provide protection and ward off infections. The lack of normal redeveloping tissue in the body's mucosal lining due to infection decreases the function of neutrophils, natural killer cells, and macrophages. Vitamin A deficiency may also interfere with neutrophil development and cytokine release, leading to an increased chance of inflammation. In addition, vitamin A deficiency alters the innate and adaptive immune response, leading to a compromised immune system.

Human VA ELISA Kit