Elevated renalase levels in patients with acute coronary microvascular dysfunction - A possible biomarker for ischemia

Int J Cardiol. 2019 Mar 15:279:155-161. doi: 10.1016/j.ijcard.2018.12.061. Epub 2019 Jan 2.

Abstract

Aims: We explored the relationship between inflammation, renalase an anti-inflammatory protein, and acute chest pain with coronary microvascular dysfunction (CMD).

Methods and results: We used cardiac Rb-82 PET/CT imaging to diagnose coronary artery disease (CAD/CALC) (defect or coronary calcification) and CMD (depressed coronary flow reserve without CAD) in patients with chest pain in an emergency department (ED). Blood samples were collected pre-imaging within 24 h of ED presentation and were analyzed for renalase and inflammatory markers including C-reactive protein, interleukins, interferon gamma, tumor necrosis factor, vascular endothelial growth factor, and metalloproteinases. Exclusions were age ≤30 years, myocardial infarction, hemodynamic instability, hypertensive crisis, heart failure or dialysis. Between 6/2014 and 11/2015, 80 patients undergoing PET/CT provided blood and were categorized as normal (18%), CAD/CALC (27%) and CMD (55%). Median renalase values were highest in patients with CMD (5503 ng/ml; IQR 3070) compared to patients with normal flows (4266 ng/ml; IQR 1503; p = 0.02) or CAD/CALC (4069 ng/ml IQR 1850; p = 0.004). CMD patients had similar median values for inflammatory markers as normal patients (p > 0.05). Renalase remained an independent predictor of CMD (OR 1.34; 95% CI = 1.1-1.7, per 1000 ng/ml) after adjustment for smoking, family history, obesity and Framingham risk score. In a model for CMD diagnosis with Framingham risk score, typical angina history and CRP, renalase improved discrimination from C-statistic = 0.60 (95% CI 0.47, 0.73) to 0.70 (95% CI, 0.59-0.82).

Conclusion: We found elevated renalase in response to ischemia from acute CMD. Its role as a biomarker needs validation in larger trials.

Keywords: Biomarker; Chest pain; Coronary microvascular dysfunction; Inflammation; PET; Renalase.

MeSH terms

  • Acute Disease
  • Adult
  • Aged
  • Biomarkers / blood
  • Coronary Artery Disease / blood
  • Coronary Artery Disease / diagnostic imaging
  • Coronary Circulation / physiology*
  • Cross-Sectional Studies
  • Female
  • Humans
  • Male
  • Microcirculation / physiology*
  • Middle Aged
  • Monoamine Oxidase / blood*
  • Myocardial Ischemia / blood*
  • Myocardial Ischemia / diagnostic imaging*
  • Positron Emission Tomography Computed Tomography / methods

Substances

  • Biomarkers
  • Monoamine Oxidase
  • renalase