Vitamin A and inflammation

A team of researchers at Case Western Reserve University School of Medicine discovered how uncontrolled vitamin A metabolism in the intestine can cause inflammation.** The study was led by Johannes von Lintig, PhD. Associate professor of pharmacology at Case Western Reserve School of Medicine. Together with colleagues from the department of pharmacology and the department of molecular biology and microbiology. The researchers focused on a branch point in the vitamin A metabolic pathway that depends on a single protein called ISX.

The way it works is simple.

Beta-carotene forms vitamin A in the small intestine. From there, most of the vitamin A is transported to other tissues to care for the functioning of various processes. Some vitamin A is also used to support immune cells in the intestine. By studying mice genetically modified to lack ISX, researchers found that this protein helps the body balance this process. They found that ISX turns on and off genes involved in beta-carotene availability. Protein helps transport the correct amount of beta-carotene to meet the body’s vitamin A needs. Immune cells depend on this mechanism to respond appropriately to foods entering the small intestine. This maintains an effective barrier against potential threats that may be transmitted through food. The researchers found that when ISX is absent, immune cells can react strongly to diets rich in beta-carotene.** ISX deletion increases gene expression 200-fold for the Bco1 enzyme. Which converts dietary beta-carotene into vitamin A. Because of this, mice without ISX overproduce vitamin A and begin converting it into retinoic acid. Which caused inflammation. The study positions ISX as an important control point in the metabolism of vitamin A. This finding represents a great advance in the understanding of inflammation and our body.