FAC U LT Y IN ACT ION
S QUE E ZING
SMHS researchers spread the word about the prevention and possible treatment of Lyme disease.
“It’s heading west, and it’s heading north and south,”
(PTLDS). Symptoms of PTLDS are primarily neurological in
says Catherine Brissette, PhD, with not so much alarm as
nature and include, among other symptoms, chronic fatigue,
resignation in her voice. “With climate change, it’s exploding
pain, cognitive impairment, migrane headaches, balance
north into Canada, into Ontario and Manitoba. And it’s moving
issues, weakness, facial palsy, and vertigo.
into places it wasn’t traditionally seen like Kentucky and Tennessee. This is a real issue.”
“So we asked ‘why?’” So Brissette and her team asked “Why?”—what was
An associate professor in the UND Department of Biomedical
contributing to this syndrome so long after treatment?
Sciences since 2010, Brissette is referring to the Lyme disease
Although possible answers to that question abound, so far
spread by deer ticks in northern latitudes across the globe. The
there has been little evidence to support any of them.
most common arthropod-borne disease affecting humans in the United States, with an estimated 300,000 cases per year, the disease bears the name of the location where it was first recognized in 1975: Lyme, Connecticut. Having spent the better part of her career studying the corkscrew-shaped bacteria that cause Lyme, Borrelia burgdorferi, Brissette’s lab at the School of Medicine and Health Sciences is today in the middle of several research projects exploring not merely the spread of Lyme but also its pathology. “There are lots of different manifestations of neurological Lyme disease and most of them are treated with antibiotics and things end up fine,” says Brissette from her office in UND’s Neuroscience Research Facility. “But there’s a portion of people who even after extensive treatment continue to have these symptoms that linger.” As Brissette puts it, while most persons who acquire Lyme disease from a tick bite undergo successful antibiotic treatment, up to 20 percent of patients suffer from a chronic condition that has been designated Post-Treatment Lyme Disease Syndrome
“The first theory is that the antibiotics simply didn’t work—and that the patient needed more. But the evidence here is weak,” Brissette continues, noting that several clinical trials exploring this question have not shown benefit for patients taking a longer course of antibiotic treatment. However, two newer—and potentially more promising— solutions to the PTLDS puzzle have emerged that involve a complex mixture of immunology, neurology, and genetics. The first involves the notion that the “debris” left behind by the dead bacteria following a course of antibiotics may either cross the blood-brain barrier or otherwise generate an inflammatory response from the person’s immune system, causing patients’ neurological symptoms. “There’s some evidence for this both in animals and humans in terms of Lyme arthritis,” Brissette continues, using the knee joint as an example. “There’s not a lot of vasculature there. So, if you have dead bacteria hanging out in the knee that doesn’t get cleared by the immune system because there’s not a lot of cellular traffic coming through, it stays. And then you have
“The longer you go without diagnosis, the more likely it is you’re going to have chronic issues.” CATHERINE BRISSETTE PhD
this stimulus where the immune system is going to keep trying to clear out these foreign bodies, but it can’t.” Although researchers don’t yet have solid evidence that there’s any Borrelia debris in the brain specifically creating PTLDS symptoms, scientists in Brissette’s lab, including third-year SMHS medical student Jacob Greenmyer, did learn something interesting recently in this regard. “Jacob showed that if you take some of the
North Dakota Medicine Fall 2018