Abstract 486: Chronic Periodontitis Induces Adverse Post-myocardial Wound Healing Through Activation of CD8+ T-cells

Abstract

Increased risk of adverse cardiac remodeling post-myocardial infarction (MI) has been observed in patients with periodontal disease. Previously, we demonstrated that chronic inflammation induced by periodontal pathogen Porphyromonas gingivalis lipopolysaccharide (LPS) resets cardiac homeostasis, causing acceleration and exacerbation of the macrophage response post-MI. We hypothesize that chronic LPS activates a memory T-cell response resulting in adverse cardiac remodeling post-MI. Analysis of the mouse heart attack research tool (mHART) 1.0 identified 135 mice (5.4 ± 0.1 months of age) associated with the LPS study that had both echo and plasma data collected. Of these 26 mice also had tissue blocks in the mHART tissue bank. Mice were grouped as follows: 1) Saline day 0 unoperated mice (D0), 2) 28 day LPS day 0 unoperated mice (LPS), 3) Saline day 1 MI (MI), and 4) 28 day LPS day 1 MI (LPS+MI). Immunofluorescence of the left ventricle (LV) demonstrated that chronic LPS increased the number of memory CD8+ T-cells (CD3+CD8+CD27+) in the LV and remained elevated in the LPS+MI group compared to D0 and MI controls. Similar to chronic LPS, ligature-induced periodontitis (21 days) also showed upregulation of CD8+ T-cells in the LV along with changes in plasma proteins associated with interleukin, cytokine, chemokine receptor binding, peptide ligand-binding, inflammasome pathway, class A/1 rhodopsin-like receptors, G-protein coupled receptor ligand binding, and RUNX1 and FOXP3 control of Treg development and signaling. To dissect T-cell mediated signaling pathways, we constantly infused an MHC-I blocking antibody (MHCi; 0.2 μg/day; n=3) by osmotic mini-pumps implanted subcutaneously 7 days before (21 days after LPS infusion) and after MI surgery. Interestingly, MHCi attenuated the effector CD8+ T-cell response (CD3+CD8+CD44+) without affecting the memory response. MHCi also attenuated macrophage numbers within the infarct, thereby improving cardiac function at post-MI day 1. Our data showed the recruitment of effector but not memory CD8+ T-cells is regulating macrophage-mediated adverse post-MI remodeling in the setting of chronic periodontitis.