Abstract 19192: In Vivo Multiphoton Microscopy Following Myocardial Infarction Reveals Vascular Disarrangement
Introduction: Perturbed cardiomyocyte contractility and vascularization post-injury contribute to disease progression. In vivo multiphoton microscopy (MPM) allows for three-dimensional visualization of cell motion within a cardiac cycle. Revascularization is considered important for tissue repair after injury, however structural abnormalities suggest inefficient vessel function. The aim of this project was to study vascular alterations following myocardial infarction using in vivo MPM.
Methods: C57Bl6 mice underwent transmural ventricular cryoinfarction (CI) with a liquid-N2-cooled copper probe. Imaging was performed in healthy controls and at 7-days post-injury. A region of the heart surface is stabilized by attaching a cover glass held by a 3D-printed titanium probe. Intravenous Texas-Red dextran is administered to label blood plasma. Imaging is conducted using a custom-built microscope equipped with high-speed image acquisition (30 frames/sec). Post-processing of images is used to align image frames according to ECG cycle. Histology for endothelial cells (PECAM-1), myofibroblasts (αSMA), and collagens (H&E, Masson’s) was performed post-imaging.
Results: In vivo MPM of the beating heart demonstrated vessel tortuosity, orientation changes and red blood cell motion. 7-days post-CI, vessel anisotropy increased within a 3D volume (Control: 8.9±1.1, CI: 17.4±1.7, p<0.05), although the number of vessel bifurcations remained unchanged compared to uninjured controls (Fig). PECAM-1 and αSMA increased confirming new vessel formation and myofibroblast proliferation compared to controls. Granulation tissue with inflammatory infiltrate and minimal fibrosis was present at 7-days post CI.
Conclusions: We have demonstrated the presence of vascular disarrangement following myocardial infarction using the novel technique of in vivo MPM. This technology allows for in vivo monitoring during active phases of cardiac repair following injury.
Author Disclosures: D.M. Small: None. J.S. Jones: None. I.I. Tendler: None. N. Nishimura: None.
- © 2016 by American Heart Association, Inc.