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Scanning Electron Microscopy of Macerated Tissue to Visualize the Extracellular Matrix
Published on: June 14, 2016
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Endogenous Modulation of Extracellular Matrix Collagen during Scar Formation after Myocardial Infarction
David Schumacher1,2,3, Adelina Curaj3,4, Mareike Staudt3
1Department of Anesthesiology, University Hospital, RWTH Aachen University, 52074 Aachen, Germany.
International Journal of Molecular Sciences
|December 11, 2022
Summary
Inflammatory cells, like neutrophils and mononuclear cells, significantly impact scar composition after myocardial infarction by altering collagen synthesis. Understanding these interactions is key to improving heart healing and reducing mortality.
Area of Science:
- Cardiovascular Biology
- Extracellular Matrix Research
- Immunology
Background:
- Myocardial infarction (MI) is a leading cause of death globally.
- Extracellular matrix (ECM) composition changes post-MI, influencing scar function.
- Collagen is the primary ECM component, and its subtypes may vary in scar tissue.
Purpose of the Study:
- To investigate how inflammatory cell recruitment influences collagen subtype synthesis in myofibroblasts post-MI.
- To determine the role of specific inflammatory pathways (IL-1, PPARγ, NF-kB, angiotensin II, PPARδ) in modulating collagen production.
- To correlate inflammatory cell infiltration with specific collagen subtype expression and scar stiffness.
Main Methods:
- Utilized knockout mouse models (CCR1-/- and CCR2-/-) to study neutrophil and mononuclear cell roles.
- Analyzed mRNA expression of various collagen subtypes in myocardial scar tissue at 4 weeks post-MI.
- Assessed scar stiffness in isolated myofibroblasts and correlated gene expression with cellular pathways.
Main Results:
- Neutrophils inhibited fibrillar collagen mRNA expression, potentially reducing scar stiffness.
- CCR1-/- mice showed altered collagen profiles (increased type 11, moderate 19, low 13/26) with reduced neutrophil infiltration.
- Mononuclear cells increased synthesis of multiple collagen subtypes but also showed complex regulatory effects on types 5 and 16.
- CCR2-/- mice exhibited higher collagen type 13 levels and reduced stiffness.
- Inflammation-related genes primarily modulated fibrillar collagen, while proliferation/differentiation genes were linked to fibrillar collagen, and angiogenesis genes to fibrillar, network-forming, and multiplexin subtypes.
Conclusions:
- Inflammatory cell subsets differentially regulate collagen synthesis and scar characteristics post-MI.
- Neutrophils and mononuclear cells play distinct roles in modulating collagen subtypes and ECM remodeling.
- Targeting inflammatory pathways presents a potential strategy for optimizing myocardial scar formation and function.
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