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Thromb Haemost 2018; 118(08): 1450-1460
DOI: 10.1055/s-0038-1661353
Atherosclerosis and Ischaemic Disease
Georg Thieme Verlag KG Stuttgart · New York

Deletion of Extra Domain A of Fibronectin Reduces Acute Myocardial Ischaemia/Reperfusion Injury in Hyperlipidaemic Mice by Limiting Thrombo-Inflammation

Mehul R. Chorawala
1   Department of Internal Medicine, University of Iowa, Iowa City, Iowa, United States
,
Prem Prakash
1   Department of Internal Medicine, University of Iowa, Iowa City, Iowa, United States
,
Prakash Doddapattar
1   Department of Internal Medicine, University of Iowa, Iowa City, Iowa, United States
,
Manish Jain
1   Department of Internal Medicine, University of Iowa, Iowa City, Iowa, United States
,
Nirav Dhanesha
1   Department of Internal Medicine, University of Iowa, Iowa City, Iowa, United States
,
Anil K. Chauhan
1   Department of Internal Medicine, University of Iowa, Iowa City, Iowa, United States
› Author Affiliations
Funding A.K.C. is supported by grants from the National Heart, Lung and Blood Institute of the National Institutes of Health grants (R35HL139926) and by Established Investigator Award 18EIA33900009 from American Heart Association.
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Publication History

18 March 2018

09 May 2018

Publication Date:
30 June 2018 (online)

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Abstract

Background Fibronectin splicing variant containing extra domain A (Fn-EDA), which is an endogenous ligand for Toll-like receptor 4 (TLR4), is present in negligible amounts in the plasma of healthy humans, but markedly elevated in patients with co-morbid conditions including diabetes and hyperlipidaemia, which are risk factors for myocardial infarction (MI). Very little is known about the role of Fn-EDA in the pathophysiology of acute MI under these co-morbid conditions.

Materials and Methods We determined the role of Fn-EDA in myocardial ischaemia/reperfusion (I/R) injury in the hyperlipidaemic apolipoprotein E-deficient (ApoE−/−) mice. Infarct size, plasma cardiac troponin I (cTnI) levels, intravascular thrombosis (CD41-positive), neutrophil infiltration (Ly6 B.2-positive), neutrophil extracellular traps (citrullinated H3-positive) and myocyte apoptosis (terminal deoxynucleotidyl transferase-mediated dUTP nick-end labelling-positive) were assessed in myocardial I/R injury model (1-hour ischaemia/23 hours of reperfusion).

Results Irrespective of gender, Fn-EDA−/−ApoE−/− mice exhibited smaller infarct size and decreased cTnI levels concomitant with reduced post-ischaemic intra-vascular thrombi, neutrophils influx, neutrophil extracellular traps and myocyte apoptosis (p < 0.05 vs. ApoE−/− mice). Genetic deletion of TLR4 attenuated myocardial I/R injury in ApoE−/− mice (p < 0.05 vs. ApoE−/− mice), but did not further reduce in Fn-EDA−/− ApoE−/− mice suggesting that Fn-EDA requires TLR4 to mediate myocardial I/R injury. Bone marrow transplantation experiments revealed that Fn-EDA exacerbates myocardial I/R injury through TLR4 expressed on the haematopoietic cells. Infusion of a specific inhibitor of Fn-EDA, 15 minutes post-reperfusion, into ApoE−/− mice attenuated myocardial I/R injury.

Conclusion Fn-EDA exacerbates TLR4-dependent myocardial I/R injury by promoting post-ischaemic thrombo-inflammatory response. Targeting Fn-EDA may reduce cardiac damage following coronary artery re-canalization after acute MI.

Keywords

fibronectins - thrombosis - inflammation - myocardial ischaemia - hyperlipidaemia

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