Physiologic, Pathologic, and Therapeutic Paracrine Modulation of Cardiac Excitation-Contraction Coupling

Area of Science:

• Cardiology
• Cell Biology
• Biomedical Engineering

Background:

• Cardiac excitation-contraction coupling (ECC) is vital for heart function.
• While beta-adrenergic signaling is known, paracrine signaling's role in ECC is less understood.
• Non-cardiomyocytes, including fibroblasts and stem cells, can modulate cardiac myocyte ECC via paracrine mechanisms.

Purpose of the Study:

• To review paracrine-mediated effects of non-cardiomyocytes on cardiac function.
• To discuss key paracrine factors, mechanisms, and their impact on ECC.
• To explore tissue-engineering and systems biology approaches for identifying paracrine mediators.

Main Methods:

• Literature review of paracrine signaling in cardiac ECC.
• Analysis of conditioned media from human adult cardiac fibroblasts (HACF) and human dermal fibroblasts (HDF).
• Functional and molecular assessment of engineered cardiac tissue (ECT) exposed to conditioned media.

Main Results:

• HACF conditioned media affected ECT contractility and ion channel gene expression, suggesting species-specific differences.
• HDF paracrine secretions showed no significant effect on ECT function or gene expression.
• Paracrine factors from non-cardiomyocytes influence cardiomyocyte hypertrophy, electrophysiology, and calcium handling.

Conclusions:

• Paracrine signaling is a significant modulator of cardiac ECC.
• Tissue-engineering combined with systems biology offers a promising avenue for discovering novel paracrine mediators.
• Understanding these paracrine mechanisms can lead to improved cell-based therapies for heart disease.