TB drugs work better with vitamin C
Washington, DC – January 3, 2018 – Studies in mice and in tissue cultures suggest that giving vitamin C with tuberculosis drugs could reduce the unusually long time it takes these drugs to eradicate this pathogen. The research is published in Antimicrobial Agents and Chemotherapy, a journal of the American Society for Microbiology.
In the
study, the investigators treated
Mycobacterium tuberculosis-infected mice with
anti-tuberculosis drugs or vitamin C alone, or the drugs and
vitamin C together. They measured M. tuberculosis (Mtb)
organ burdens at four and six weeks post treatment.
Vitamin C had no activity by itself, but in two
independent experiments, the combination of vitamin C with the
first-line TB drugs, isoniazid and rifampicin, reduced the organ
burdens faster than the two drugs without vitamin C, said first
author Catherine J. Vilcheze, Ph.D. Instructor, Department of
Microbiology & Immunology, Albert Einstein College of
Medicine, Bronx, NY. Experiments in infected tissue cultures
demonstrated similar results, shortening the time to
sterilization of the tissue culture by seven days.
“Our study shows that the addition of vitamin C to
TB drug treatment potentiates the killing of Mtb and could
shorten TB chemotherapy,” said principal investigator
William R. Jacobs, Jr., PhD., Investigator, Howard Hughes
Medical Institute, Einstein College of Medicine. That’s
important because treatment of drug susceptible tuberculosis
takes six months, “resulting in some treatment
mismanagement, potentially leading to the emergence and spread
of drug-resistant TB,” said Dr. Jacobs.
Such long term treatment is needed for tuberculosis
because a subpopulation of Mtb cells can form Mtb persister
cells, dormant cells that are virtually impervious to
antimicrobials.
In earlier studies, the investigators discovered that
while high levels of vitamin C will kill actively dividing
cells, lower concentrations will stimulate respiration and
prevent the formation of persisters, said Dr. Jacobs. Then, in
the presence of TB drugs, that increased respiration will lead
to rapid death of the cells. “Thus in our new paper, we
postulate that vitamin C is stimulating respiration of the Mtb
cells in mice, thus enabling the action of isoniazid and
rifampicin.”
A French study conducted in 1948 suggested that vitamin C
was safe for humans, and potentially beneficial. Investigators
gave high daily doses of vitamin C to terminally ill patients
with no side effects. While the infection did not regress, that
study characterized other effects as “remarkable:”
bedridden patients regained appetite and physical activity.
Tuberculosis is a major worldwide public health problem,
infecting the lungs and other organ systems. In 2016, the
disease sickened more than 10 million people worldwide, and
killed 1.7 million. In the United States, cases number in the
low thousands, out of a population of around 3,30 million.
Treatment of multidrug resistant TB takes at least two years,
and requires use of toxic second-line TB drugs with severe side
effects.
“Vitamin C is known to be safe and our current mouse
studies suggest that vitamin C could enhance TB
chemotherapy,” said Dr. Jacobs. “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.”
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The American Society for Microbiology is the largest single life science society, composed of more than 50,000 scientists and health professionals. ASM's mission is to promote and advance the microbial sciences.
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