In vitro models of proarrhythmia.

Area of Science:

• Computational toxicology
• Pharmacology
• Cardiovascular research

Background:

• Proarrhythmia models utilize electrophysiological markers to assess torsade de pointes (TdP) risk.
• Current models show correlations with clinical outcomes but lack independent validation, necessitating cautious interpretation.
• No single model has demonstrated clear superiority, and direct clinical extrapolation requires careful consideration.

Purpose of the Study:

• To review and discuss the merits and shortcomings of various proarrhythmia models.
• To evaluate the current state and future potential of in silico and in vitro proarrhythmia assessment methods.
• To address the challenges hindering regulatory acceptance and wider adoption of these predictive models.

Main Methods:

• Review of existing literature on proarrhythmia models, including in silico (subcellular to whole system) and in vitro approaches.
• Discussion of the electrophysiological markers and variables employed by different models.
• Analysis of the predictive capabilities, limitations, and clinical relevance of current proarrhythmia assessment strategies.

Main Results:

• In silico models are increasingly used in early drug discovery, potentially shifting focus from biological experiments to simulation analysis.
• In vitro models challenge existing surrogates for TdP and current non-clinical risk assessment strategies.
• A lack of clear understanding of proarrhythmic mechanisms contributes to regulatory reluctance to adopt these models.

Conclusions:

• Proarrhythmia models hold potential for unraveling TdP mechanisms, but wider acceptance hinges on a clear, agreed-upon understanding of key proarrhythmic mechanisms.
• Ongoing improvements and greater acceptance could lead to these models becoming a primary tool in drug discovery and risk assessment.
• Further research and validation are crucial for bridging the gap between in silico/in vitro findings and clinical application.