SUNDAY, SEPTEMBER 25, 2016

Vitamin A may help body fight TB

Vitamin A may assist the human immune system in fighting off tuberculosis, according to a study published on Saturday in the Journal of Immunology.

Researchers at the University of California at Los Angeles tested the role of nutrients in helping the immune system battle major infections. The team found that vitamin A and a specific gene help the immune system by lowering the level of cholesterol in cells infected with TB. This mechanism is important because cholesterol can be used by TB bacteria for nutrition and other requirements.

"If we can reduce the amount of cholesterol in a cell infected with tuberculosis, we may be able to aid the immune system in better responding to the infection," Philip Liu, a senior author on the study, said. "Understanding how nutrients like vitamin A are utilized by our immune system to fight infections may provide new treatment approaches."

The researchers found that the action of vitamin A was dependent on the expression of a gene called NPC2.

"We were very surprised that this particular gene was involved, since it has traditionally been associated with cholesterol transport and not immune defense," Elliot Kim, a co-first author on the study, said.

The team found that vitamin A induces cells to express NPC2, which helps the cell effectively remove cholesterol from cellular lysosomes so the bacteria is unable to access it. Lysosomes, which play an important role in fighting infections, can resume killing bacteria once the cholesterol is removed.

Matthew Wheelright, a co-first author on the study, said scientists may be able to target the same pathways that regulate cholesterol within a cell to assist the immune system to fight infection.

The next step of the research will concentrate on learning how the immune system takes inactive vitamin A, known as retinol, and converts it into active all-trans reinoic acid.