Abstract 13976: Optogenetic Monitoring of Endocardial Calcium Transients in vivo Using a Minimally Invasive Fiber Optic Approach
Rationale: In vivo electrophysiology and contraction can be studied very well using minimally invasive methods. Contrarily, myocardial calcium signaling cannot be studied in vivo, although it is a crucial aspect of cardiac remodeling.
Objective: We aimed to establish a method that can be used to study myocardial calcium signaling in vivo.
Methods and Results: We employed the optogenetic fluorescent calcium sensor GCaMP3 to record calcium transients from the left ventricular endocardium of closed chest mice (n=8, inducible, cardiomyocyte[[Unsupported Character - Codename ­]]specific GCaMP3 transgenic overexpression). Excitation of the sensor and detection of fluorescence emission was done using a thin plastic optical fiber (250 μm) that was introduced via the carotid artery into the left ventricular cavity. Combining optogenetics with fiber optics, we were able to record endocardial calcium transients with good signal to noise ratio (6.9 ± 0.2) for up to 30 minutes at physiological heart rates, without significant bleaching of fluorescence.
Conclusions: Our results demonstrate that by employing optogenetics, calcium signaling can be studied in vivo in the presence of physiologically important factors such as hemodynamic load, innervation and interaction with other organs.
We expect that this approach is also suitable for other optogenetic sensors, greatly expanding possibilities for in vivo studies.
Author Disclosures: L. Menke: None. I. van Asten: None. M.S. Fontes: None. L. van Stuijvenberg: None. T.A. van Veen: None. M.A. Vos: None. T.P. de Boer: None.
- © 2015 by American Heart Association, Inc.