Altering systolic deformation, matrix orientation, and continuity in the infarct area resulted in complete disarray in the organization of collagen within the infarct scar in pigs.
Do structural and mechanical factors (deformation, matrix orientation, and continuity) influence collagen organization in myocardial infarct scars in a porcine model?
This preclinical study demonstrates that preexisting extracellular matrix orientation and local systolic deformation are critical factors guiding fibroblast collagen deposition and organization in myocardial infarct scars.
Although large collagen fibers in myocardial infarct scar are highly organized, little is known about mechanisms controlling this organization. The preexisting extracellular matrix may act as a scaffold along which fibroblasts migrate. Conversely, deformation within the ischemic area could guide fibroblasts so new collagen is oriented to counteract the stretch. To investigate these potential mechanisms, we infarcted three groups of pigs. Group 1 served as infarct controls. Group 2 had the endocardium slit longitudinally to alter local systolic deformation. Group 3 had a plug sectioned from ischemic tissue and rotated 90 degrees. The slit altered systolic deformation in the infarcted tissue, changing circumferential strain from expansion to compression and increasing radial strain and shears and the variability of collagen fiber angles but not the mean angle. In the plug pigs, when deformation, matrix orientation, and continuity are altered in the infarct area, the result is complete disarray in the organization of collagen within the infarct scar.
Zimmerman et al. (Sat,) conducted a other in Myocardial infarction. Altering local systolic deformation (endocardium slit) or matrix orientation (plug rotation) vs. Infarct controls was evaluated on Collagen fiber organization and systolic deformation. Altering systolic deformation, matrix orientation, and continuity in the infarct area resulted in complete disarray in the organization of collagen within the infarct scar in pigs.