Vitamin C Aids Effectiveness of Drugs to Treat Tuberculosis

Investigators from the Albert Einstein College of Medicine, Bronx, New York have found that when used in conjunction with anti-tuberculosis drugs, vitamin C helped eradicate Mycobacterium tuberculosis (Mtb).

According to the World Health Organization (WHO), tuberculosis (TB) is one of the top 10 causes of death worldwide, and the number 1 killer of individuals who are infected with HIV. WHO’s statistics indicate that 10.4 million people fell ill with TB in 2016, and 1.7 million died from the disease, including 0.4 million among individuals with HIV. In addition, WHO reports that there were a total of 600,000 new cases of TB resistant to rifampicin, “the most effective first-line drug,” and of these cases, almost 500,000 (490,000) had multidrug-resistant TB.

More effective treatments against this virulent pathogen are imperative and the investigators from Albert Einstein may have found a way to help the currently available treatments do their job better.

For the study, “the investigators treated Mtb-infected mice with the anti-tuberculosis drugs isoniazid and rifampicin, vitamin C alone, or the drugs and vitamin C together. They measured Mtb organ burdens at 4 and 6 weeks posttreatment,” according to a press release on the study.

Although the vitamin C did not have any action against Mtb itself, when combined with the first-line medications, it “reduced the bacterial burden in the lungs of Mtb-infected mice faster than isoniazid and rifampicin combined in 2 independent experiments,” according to the study. After repeating the experiments in tissue cultures, the investigators found that the combination shortened “the time to sterilization of the tissue culture by 7 days.”

Speaking on the ramifications of these results in the press release, principal investigator William R. Jacobs, Jr, PhD, investigator, Howard Hughes Medical Institute, Einstein College of Medicine stated, “Our study shows that the addition of vitamin C to TB drug treatment potentiates the killing of Mtb and could shorten TB chemotherapy.” This is important because treatment of drug-susceptible tuberculosis takes 6 months, "resulting in some treatment mismanagement, potentially leading to the emergence and spread of drug-resistant TB,” he concluded.

The reason that treatment for TB is longer than treatment duration for other infections is because Mtb cells can form persister cells which lie dormant and are unaffected by antibiotics. In previous studies, the investigators found that low levels of vitamin C are able to prevent these persister cells from forming by stimulating respiration in the cells, eventually leading to the rapid death of the cells. Dr. Jacobs stated in the press release that the investigators believe that, “vitamin C is stimulating respiration of the Mtb cells in mice, thus enabling the action of isoniazid and rifampicin.”

“Vitamin C is known to be safe and our current mouse studies suggest that vitamin C could enhance TB chemotherapy,” Dr. Jacobs concluded. “A clinical trial of vitamin C with TB chemotherapies could demonstrate that such an adjunct therapy could reduce patients' exposure to toxic TB drugs and also reduce the spread of TB from infected individuals."