Project 462189

Coronary bypass grafting and valve repair are common cardiac surgeries which are performed daily in almost every large hospital in Canada. Yet, despite everyone's best efforts, serious adverse events requiring acute care or even hospital readmission can occur in up to 25% of patients. This means that some factor or factors important for a full and rapid recovery are not being well managed. Antibiotic use and lack of solid food early after the surgery likely change the bacteria in the intestine. In this application, we will investigate if changes in bacteria and small molecules found after a major surgery are linked with a worse outcome after a heart surgery. We will test if replacement of the bacteria with normal bacteria or treatment with a bacteria-supporting diet will allow full recovery. Using a mouse model, we found that the types of bacteria and small molecules in the gut were different when older male and female mice were compared and were different again after a heart surgery. In this project, we will focus on how the surgery changed the bacteria and how the changes in bacteria hampered recovery from a heart surgery. We will identify bacteria in the gut that are prominent in mice that recover well versus those that are dominant in mice which recover poorly or not at all. We will determine if these are the same in male and female mice. Transplant of gut bacteria or a change in diet to better support the bacteria will test if these interventions could make the mice recover better. We will test if diet supplementation before surgery will help people recover better after undergoing heart surgery. In this way, we will find out if improvements in gut health will make it easier for the aged to recover quickly after surgery and if this should be tailored to their sex. Although we focus on cardiac surgery, these interventions may also help those undergoing other surgeries.