Statins May Help Block Transmission of Lyme Disease

A recent study found that treatment with cholesterol-lowering statins reduced the number of Borrelia burgdorferi bacteria in rodents, which helped to block transmission of Lyme disease.

Lyme disease is a systemic disorder caused by the spirochete bacterium Borrelia burgdorferi. This bacterium is transmitted to mammalian hosts from arthropod vectors, specifically Ixodes spp. ticks. Lyme disease is the most prevalent arthropod borne disease in the USA with over 25,000 cases confirmed by the Centers for Disease Control and Prevention in 2014.

Investigators at the University of Texas at San Antonio (USA) decided to attack B. burgdorferi through its 3-hydroxy-3-methyl-glutaryl-coenzyme A reductase, which serves as a rate limiting enzyme of the mevalonate pathway that contributes to the synthesis of components critical for building the bacterium's cell wall.

In this study C3H/HeN mice, with or without statin treatment, were infected with 1000 spirochetes per mouse. The spirochetes were found to spread to all tissues with a few exceptions. Though there was no significant difference in bacterial dissemination to distal tissues between statin-treated and untreated mice, the investigators wanted to determine whether there were differences in the numbers of bacteria migrating to specific tissues. To that end, total genomic DNA was extracted from a portion of skin, spleen, right inguinal lymph node, and right tibiotarsal joint and subjected to quantitative real-time PCR analysis using primers specific for B. burgdorferi genes.

Results published in the March 16, 2016, online edition of the journal Microbes and Infection revealed that there was a significant decrease in the numbers of bacteria in each of the tissues tested with the exception of the joints. There were higher levels of reduction seen in the lymph nodes and spleens of mice treated with simvastatin when compared to the same tissues from mice treated with lovastatin, while there was a higher level of reduction in the skin of lovastatin-treated mice.

"We have figured out that there is one enzyme in the Lyme disease bacteria that is essential for creating its cell wall, which would allow the Lyme disease bacteria to live and cause infection," said senior author Dr. Janakiram Seshu, associate professor of biology at the University of Texas at San Antonio. "We discovered that this enzyme can be inhibited by statins, which means that one class of drugs could reduce the number of infectious bacteria in the reservoir hosts. First we want to determine how statins can be used to stop the growth of the pathogen and how we can exploit these findings to our benefit. Our hope is that if we reduce the number of viable organisms in infected reservoir hosts then we can block the transmission to a point that the disease does not affect humans significantly in many areas of the USA."

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University of Texas at San Antonio