Myocardial Inflammation Predicts Remodeling and Neuroinflammation After Myocardial Infarction

J Am Coll Cardiol. 2018 Jan 23;71(3):263-275. doi: 10.1016/j.jacc.2017.11.024.


Background: The local inflammatory tissue response after acute myocardial infarction (MI) determines subsequent healing. Systemic interaction may induce neuroinflammation as a precursor to neurodegeneration.

Objectives: This study sought to assess the influence of MI on cardiac and brain inflammation using noninvasive positron emission tomography (PET) of the heart-brain axis.

Methods: After coronary artery ligation or sham surgery, mice (n = 49) underwent serial whole-body PET imaging of the mitochondrial translocator protein (TSPO) as a marker of activated macrophages and microglia. Patients after acute MI (n = 3) were also compared to healthy controls (n = 9).

Results: Infarct mice exhibited elevated myocardial TSPO signal at 1 week versus sham (percent injected dose per gram: 8.0 ± 1.6 vs. 4.8 ± 0.9; p < 0.001), localized to activated CD68+ inflammatory cells in the infarct. Early TSPO signal predicted subsequent left ventricular remodeling at 8 weeks (rpartial = -0.687; p = 0.001). In parallel, brain TSPO signal was elevated at 1 week (1.7 ± 0.2 vs. 1.4 ± 0.2 for sham; p = 0.017), localized to activated microglia. After interval decline at 4 weeks, progressive heart failure precipitated a second wave of neuroinflammation (1.8 ± 0.2; p = 0.005). TSPO was concurrently up-regulated in remote cardiomyocytes at 8 weeks (8.8 ± 1.7, p < 0.001) without inflammatory cell infiltration, suggesting mitochondrial impairment. Angiotensin-converting enzyme inhibitor treatment lowered acute inflammation in the heart (p = 0.003) and brain (p = 0.06) and improved late cardiac function (p = 0.05). Patients also demonstrated elevation of cardiac TSPO signal in the infarct territory, paralleled by neuroinflammation versus controls.

Conclusions: The brain is susceptible to acute MI and chronic heart failure. Immune activation may interconnect heart and brain dysfunction, a finding that provides a foundation for strategies to improve heart and brain outcomes.

Keywords: heart failure; inflammation; macrophages; myocardial infarction; neurodegeneration; positron emission tomography.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Brain / diagnostic imaging*
  • Brain / immunology
  • Forecasting
  • Inflammation / diagnostic imaging
  • Inflammation / physiopathology
  • Mice
  • Mice, Inbred C57BL
  • Molecular Imaging / methods
  • Myocardial Infarction / diagnostic imaging*
  • Myocardial Infarction / immunology
  • Myocardium / immunology
  • Myocardium / pathology*
  • Ventricular Remodeling / physiology*