Category: Assay Development and Screening
Substantial percentages of new chemical and biological entities fail in late-stage human drug testing, receive regulatory "black box" warnings or are removed from the market for cardiotoxicity reasons after regulatory approvals. This lack of early predictability increases enormously R&D cost for developing products that would finally fail to reach the market or withdrawn after commercialisation.
We present the ZeCardio platform, in which we use zebrafish larvae to perform high throughput screening of large libraries in live organism for cardiotoxicity assessment and cardiomyopathy therapy discovery. The advantages of the zebrafish larvae model are two-fold: i) large progeny, which develops externally and rapidly, allows parallel testing of dozens of molecules and ii) zebrafish larvae are transparent and small which make them ideal for non-invasive approaches, such as in vivo imaging. On top of that, the zebrafish cardiovascular system is analogous to humans, allowing the use of zebrafish larva for predicting the impact of drugs with high reliability. This model can satisfy the need for early risk assessment during the drug discovery process in a cost-effective manner. Thereby, maintaining economic sustainability of R&D costs.
The platform integrates a high throughput fluid system and a high speed wide field imaging setup to allow the screening of hundreds of embryos in a day. For screening drug libraries, we use the double transgenic line Tg[cmlc2:GFP] Tg[gata1:DsRed] that labels a subset of blood cells in red and myocardial cells in green. The setup enables the fully automatised acquisition of cardiovascular in vivo data. The acquired high-resolution video data can then be analysed by our custom-made software: ZeCardio™. Here we can extract quickly and efficiently a plethora of relevant cardiovascular parameters: heart rate, arrhythmia, AV blockage, ejection fraction and blood flow and vasodilatation/ constriction. Most of these physiological parameters are not possible to test in in vitro systems (i.e.: ejection fraction or blood flow) and/or are extremely expensive and time-consuming to test in larger animals.
Here, we present results of the pilot study: On one hand, we compare robustness of the high throughput approach with the previously employed manual approach. On the other hand, we compare results from cardiomyocytes and zebrafish embryos to define the predictive value of using zebrafish versus in silico/in vitro models.
Sylvia Dyballa– Research Scientist, ZeClinics S.L., Barcelona, Catalonia, Spain