(E-183) High-throughput Longitudinal Monitoring of Human Heart Organoids using Optical Coherence Tomography

Introduction:: Self-organized human heart organoids (hHOs) have been developed to recapitulate the key functions of mammalian early heart development with multiple cell types (1). They have been widely applied in basic research, disease modeling, drug screening and transplantation (2). To assess the hHOs, a noninvasive optical imaging modality, Optical Coherence Tomography (OCT), has been adopted to reveal their morphological and functional characteristics (3). However, the current imaging platform doesn’t support environmental control, leading to limited imaging time and frequency. Here, we demonstrate a custom spectral-domain OCT with built-in fluorescence imaging capability inside an incubator to achieve a high-throughput assessment of hHOs cultured in different maturation media. This provides a useful imaging platform for monitoring hHOs development in unperturbed conditions with high temporal resolution.

Materials and Methods:: The heart organoids were cultured following the protocol in (4) with wild-type C human induced pluripotent stem cell (WTC-hiPSC) line with genetically engineered GCaMP6f. From Day 20 to Day 30, hHOs were divided into four groups, each treated with specific maturation media (control, MM, EMM1, EMM2). The imaging platform integrates a spectral domain OCT (SD-OCT) and a 2D fluorescence imaging system. The axial resolution and transverse resolutions are ~2.1 μm and ~3.9 μm in tissue. OCT characterized the morphological properties and movements of hHOs. The fluorescence imaging visualized the cardiac electrophysiological features and indicated their contractility. The hHOs were maintained in the incubator except for media change. OCT images were processed through ImageJ and Amira.


Results, Conclusions, and Discussions:: The preliminary data has proven the feasibility of this technology to monitor and identify features of hHOs during longitudinal imaging. We used traditional SD-OCT and identified increased chamber size in the EMM2 condition (shown in Figure 1. (a) (b)). We demonstrated the high-throughput OCT imaging capability using a 96-well plate on earlier days (shown in Figure 1. (c)).

In conclusion, we successfully cultured human heart organoids and performed OCT inside the incubator. After optimization of culture and imaging protocol, we will perform comprehensive characteristics to assess hHOs functionally and morphologically with denser time points.


Acknowledgements (Optional): : We thank Dr. Nathaniel Huebsch and his lab for sharing the WTC hiPSC GCaMP6f cell line and lab equipment. Funding Sources: NIH grants R01EB025209, R01HL156265, R21EB03268401A1, K01HL135464, R01HL151505, and AHA 19IPLOI34660342.


References (Optional): : (1) Lewis-Israeli, Y.R., et al. Nat Commun, 2021, 12, 5142. (2) Kim, H., et al. Cell Stem Cell, 29(4), 503-514. (3) Ming, Y, et al. Biosens. Bioelectron. 2022, 207, 114136. (4) Volmert, B., et al. bioRxiv, 2022.12.16.519611.