Lorraine Chalifour, PhD

The intestinal microbiome senses and reacts to our environment. Dysbiosis is an altered microbiome with reduced bacteria diversity, increased mucosal barrier permeability and aberrant local immune responses. Men and women are often malnourished before cardiac surgery and are at high risk for intestinal dysbiosis given dietary insufficiency and antibiotic use. Using a mouse model of a major cardiac surgery we are testing the hypothesis that surgery induces a sex-dependent gut dysbiosis that hampers healing.

We have 3 aims:

• First, we will define the physiological, immune, microbiota and metabolome responses post-cardiac surgery. Our goal is to characterize surgery-induced gut dysbiosis, cardiac structure/function, and inflammatory cell infiltration into the heart and to assess the potential for gut-specific changes to negatively affect cardiac repair and function post-surgery in mice and then humans.
• Secondly, we plan to re-engineer the mouse gut microbiome by transplant of mouse or human fecal matter. We will test the impact of antibiotics usually prescribed on the gut microbiota composition. Here, we will test if the addition of beneficial bacteria will alleviate gut dysbiosis and if antibiotics hinder or help recovery.
• Thirdly, we are investigating the role of diet and diet supplementation during the immediate post-surgery period on recovery. We test a resistant starch enriched diet which is designed to increase beneficial bacteria on recovery. Mimicking a Western diet typical of the malnourished elderly, we will test if a poor diet impairs recovery equally in male and female mice and if supplementation of microbiota-sparing nutrients will allow a better recovery.