Excitation-Contraction-Energy (ECE) Coupling

ECE CouplingCardiac contraction is initiated by an electrical stimulation, i.e., action potential. Intracellular Ca2+-transient couples action potential and cardiac contraction. Cardiac contraction is also coupled to mitochondria that replenish energy (i.e., ATP) and recycle metabolites (ADP and Pi). InvivoSciences analyzes all those parameters to determine drug-induced or genetically driven effects.

Applications:

  • Drug induced cardiotoxicity analysis 3D Tissue Based Cardiac Toxicity Assay (PDF)
  • Discovery of effective compounds to improve cardiac physiology
  • Analysis of potential drug targets
  • Investigate mechanisms of inherited cardiac diseases
  • Optimizing lead compounds
  • Genetic-trio analysis for Precision Medicine Development

Engineered Heart Tissues: Three dimensional (3D) cultures of cardiac cells derived from human induced pluripotent stem cells (iPSCs) reconstitute spontaneously beating tissues in 96-well plates (MC-96™) or 8-well chambers (MC-8™).

Assays: LITA™ (Live in Tissue Analyzer) measures action potential, Ca-transient, and membrane potential using fluorescent dye-reporters that rapidly change their intensities. Ultra-rapid optical detection devices (e.g., CLARIOstar, or FDSS/uCell) capture changes in those parameters between cardiac beats. Force of contraction, contractility, contraction duration, and frequency are measured using Palpator™ developed by InvivoSciences. LITA™ can be installed for an in-house operation with ready-to-use live EHTs shipped by IVS.

AP beatsCardiac Action Potential: Voltage sensitive dye (FluoVolt, Life Technologies) reports changes in membrane voltage

Ca2+-transient: Calcium sensitive dye (Fluo 4 AM, Life Technologies) reports changes in intracellular Ca concentration (see application note published with BMG LABTECH)

Cardiac ContractilityCardiac Force of Contraction: Force of contraction of beating human EHTs (electrically paced or unpaced) under the following conditions:

  • Isometric steady state
  • Varying loading conditions (different strain, i.e. stretch level)

Mitochondrial Membrane Potential: Positively charged TMRE (tetramethylrhodamine, ethyl ester, Sigma) dye that is permeable to plasma membrane accumulates on negatively charged mitochondrial membrane depending on their activity level.

  • CLARIOstar measures 100 data points/sec
  • uCell/FDSS captures whole-plate images with ~100 images/sec
  • Depending on assays, a multi-probe Palpator™ measures 192-384 data points/hr