Microbe-Related Modulation of Neointimal Hyperplasia after Arterial Injury

It is increasingly evident that gut microbiota are drivers of chronic inflammatory conditions including diabetes mellitus and obesity; unfortunately, the influence of host-gut microbial cross-talk on inflammation in peripheral arteries and arterial remodeling after injury is not well understood. Although it is accepted that local and systemic inflammation drive the development of restenosis after cardiovascular interventions such as bypass surgery, balloon angioplasty, and stenting, the role of gut microbes as the source or regulators of the inflammatory process is not well delineated. The PI has previously demonstrated that modulation of gut microbiota by antibiotics to permit expansion of gram-negative organisms is associated with exacerbated neointimal hyperplasia development after balloon angioplasty in a rat model of arterial injury. Furthermore, the PI observed that exchanging microbiota between genetically distinct rats by cage sharing resulted in modulation of both their strain-related neointimal hyperplasia phenotypes and local arterial and systemic inflammation after angioplasty. In addition, relative abundance of 5 specific gut bacterial genera regardless of cage sharing status or rat strain were significantly associated with neointimal hyperplasia development. Taken together, these preliminary data support our hypothesis that specific gut microbiota have a disease-modifying effect on neointimal hyperplasia by regulating the host inflammatory response. To explore this hypothesis, we propose the following aims for this 2-year proposal: Aim 1. Investigate the effect of these specific bacterial genera on neointimal hyperplasia development in specific pathogen-free and germ-free mouse models of arterial injury and assess their effect on systemic and local arterial inflammation. Aim 2: Evaluate the effect of these specific bacterial genera on intestinal inflammation and permeability. The insight on how these specific gut microbiota drive host intestinal, arter