Guest Speakers

Chris Lowry,”Effects of stress on the gut microbiome.”

Christopher A. Lowry, Ph.D., is an Associate Professor in the Department of Integrative Physiology and Center for Neuroscience at the University of Colorado Boulder, with a secondary appointment in the Department of Physical Medicine and Rehabilitation (PM&R) and Center for Neuroscience at the University of Colorado Anschutz Medical Campus (AMC), a Principal Investigator in the Department of Veterans Affairs Eastern Colorado Health Care System, VA Rocky Mountain Mental Illness Research, Education, & Clinical Center (MIRECC), Denver Veterans Affairs Medical Center (VAMC), and director of the Behavioral Neuroendocrinology Laboratory at CU Boulder.

He is Co-Director, with Dr. Lisa Brenner, of the Military and Veteran Microbiome Consortium for Research and Education (MVM-CoRE). Dr. Lowry’s research program focuses on understanding stress-related physiology and behavior with an emphasis on the role of the microbiome-gut-brain axis in stress resilience, health and disease.

 Abstract: Novel prevention and treatment strategies are urgently needed to reduce the burden of stress-related psychiatric disorders, including posttraumatic stress disorder (PTSD) and major depressive disorder (MDD). Both preclinical and clinical studies suggest that inflammation increases vulnerability to development of anxiety and affective disorders.

Consequently, immunoregulatory strategies to decrease inflammation have potential for the prevention and treatment of these disorders. Using a murine model of chronic psychosocial stress, the chronic subordinate colony housing (CSC) model, we found immunization with a heat-killed preparation of Mycobacterium vaccae, a bioimmunomodulatory agent previously shown to activate regulatory T cells (Treg) and to increase production of anti-inflammatory cytokines, prevented development of a PTSD-like syndrome.

Immunization with M. vaccae antigen induced a more proactive emotional coping style during exposure to a dominant aggressor, and, in association with suppression of proinflammatory cytokine secretion, prevented stress-induced development of spontaneous colitis and aggravation of colitis in a model of inflammatory bowel disease. Analysis suggests that the protective effects of M. vaccae immunization are due to protection from a stress-induced proinflammatory gut microbial community. Consistent with this hypothesis, protective effects of immunization were absent following Treg depletion. These data provide a hypothetical framework for development of novel strategies for prevention of stress-related psychiatric disorders in vulnerable individuals. Clinical trials investigating the potential health benefits of treatment with immunoregulatory probiotics in Veterans with PTSD are ongoing.