Monitoring Cardiac Contractility
Technology - State of the Art
In pre-clinical drug development, cardiac contraction analysis of potential drug candidates is one of the crucial steps to ensure a successful and reliable data outcome for clinical studies. Safety, toxicology and efficacy departments all over the world are seeking for a modern contractility assay that combines the reliability of traditional techniques like the Langendorff Heart with modern high-throughput and predictive human cell models.
As member of the HESI Cardiac Safety Technical Committee, we are part of the association to reduce drug-related cardiovascular side effects and have developed a new approach towards more efficient and predictable cardiotoxicity studies - the FLEXcyte Technology!
Co-developed by innoVitro and Nanion Technologies, the FLEXcyte technology is based on a special FLX-96 well plate that contains high-precision, ultra-thin and hyperelastic silicone membranes instead of stiff plastic surfaces as basis for human iPSC-derived cardiomyocytes. This FLEXcyte 96 plate is analysed in the FLEXcyte 96 device that comes as an add-on system for the CardioExcyte 96, an independent bench top incubation system. In the FLEXcyte 96-well plate, the cells adhere as monolayers on the flexible substrates and the contractility of the synchronized cell layers is recorded.
While being deflected by the weight of the culture medium, rhythmic contraction of the cardiomyocytes lift the membranes in the 96-well upwards. By measuring the changes in deflection, the mechanical stress can be calculated.
The Data Control software fascilitates deep analysis of all relevant contractile parameters. An adaptive signal detection algorithm extracts the positions and values of beating events, rising and falling times, beat durations, arrhythmic events and most importantly contraction force (mN/mm2).
This unique technology allows for recordings in an in vivo-like environment close to mechanical conditions of the heart and greatly enhances the evaluation of drug candidates in cardiac safety, tox and efficacy studies.
History of FLEXcyte Technology
The predecessor of the FLEXcyte Technology has been developed at the University of Applied Sciences Aachen in 2001 and was improved and known over the years as the “CellDrum”. In its early years it was exclusively used for academic purposes, due to the low throughput - a limiting factor for higher throughput needing pharma working in the pre-clinical drug development sector.
As part of the doctoral thesis by Matthias Goßmann, one of the founders of innoVitro, the CellDrum was further developed into an industrial demonstrator and validated on a wide range of pharmacological agents.
In 2018, Dr. Matthias Goßmann and Peter Linder, co-founded innoVitro GmbH and found a reliable partner in Nanion Technologies to finally solve the throughput issue. The outcome of this fruitful partnership was the FLEXcyte 96 device, capable of measuring contractility events on a special 96 well plate containing flexible membranes instead of stiff plastic surfaces allowing in vivo-like cardiac contractility behaviour of the cells. The FLEXcyte 96 device is produced and distributed by Nanion Technologies. FLX-96 plate production and distribution as well as services carried out with the FLEXcyte 96 system are performed by innoVitro.
In combination with human iPSC derived cells, the FLEXcyte 96 Technology overcame all obstacles and entered pre-clinical safety, tox and efficacy departments quickly after its launch in 2019.
A physiological environment, as given by the FLEXcyte 96 technology, is crucial for human iPSC- derived cardiomyocytes to develop a mature functional phenotype in vitro. Other maturation supporting cues, such as contractile stimulation via optogenetics or mechanical pressure as well as prolonged cell culture times can be additionally applied to the FLEXcyte system when needed.
FLEXcyte Maturation Effect on human iPSC derived Cardiomoycytes
Standard cultivation methods are still based on stiff glass or plastic surfaces. Neither reflects the physiological auxotonic environment cells would experience naturally. The FLEXcyte plates mimic the mechanical conditions of real biological tissue via ultra-thin hyperelastic silicone membranes that form a biohybrid with the cardiac tissue. This auxotonic and natural environment supports the development of a mature phenotype of the cultured human iPSC-derived cardiomyocytes in vitro. This pro-maturation effect elicited by the FLEXcyte 96 technology cannot be reached with other contractility assays commonly used for drug development purposes.
Optical stimulation of hiPSC-cardiomyocytes on the FLEXcyte 96 system
Optical stimulation is an important method to foster cardiomyocyte maturation in vitro and to modulate cardiac beating behaviour when needed. Human iPSC-derived cardiomyocytes are plated on FLEXcyte 96 plates until proper network formation (approx. 4-5 days). The cells are transfected with channelrhodopsin2 using the Fuse-It- mRNA transfection kit (beniag GmbH) and analyzed with the FLEXcyte 96 system 24 hours later. Spatially uniform stimulation of cells is controlled by the optical lid CardioExcyte 96 SOL, containing one LED for each well. Stimulation sweeps can be carried out for 30 seconds or longer.
Scientific data in cooperation with: Dr. Marco Hoffmann and Sven Gerlach. RNA Technologies at Institute of Biological Information Processing Mechanobiology (IBI-2) Forschungszentrum Jülich