Figure 5.

Putative mechanism by which Bifidobacterium animalis subsp. lactis 420 (B420) treatment attenuates cardiac injury following myocardial infarction (MI). The putative mechanisms by which B420 may impact cardiac injury based on our data and findings in the literature. The first step is the ingestion of B420 and entry to the gut. It is unclear whether B420 colonises the gut during the administration period, but it is known that B420 fermentation and/or interaction with the gut activates a proportion of the T_reg population. T_reg activation by B420 administration either directly or through the attenuation of pro-inflammatory cytokines attenuates cardiac injury due to MI. Our data also suggests that B420 administration hastens the transition to reparative, M2 type macrophages, potentially through activated T_reg cells. The red arrow indicates a pro-inflammatory impact that would exacerbate MI; the green arrow represents an anti-inflammatory impact that would mitigate MI.