Cardiac actions of thyroid hormone metabolites

Area of Science:

• Endocrinology
• Cardiovascular Physiology
• Molecular Biology

Background:

• Thyroid hormones (THs) are crucial regulators of cardiac function, primarily through genomic mechanisms.
• Emerging research highlights non-genomic actions of THs and their metabolites (THMs) in cardiac (patho)physiology.
• Understanding these diverse actions is vital for comprehending cardiac regulation.

Purpose of the Study:

• To review the classical and non-classical cardiac effects of various thyroid hormone derivatives.
• To elucidate the roles of iodothyronines, thyronamines, and iodothyroacetic acids in cardiac function.
• To synthesize current knowledge on THs' impact on cardiac performance.

Main Methods:

• Literature review of studies investigating thyroid hormone actions on the heart.
• Analysis of data concerning genomic and non-genomic effects.
• Categorization of effects based on specific thyroid hormone derivatives.

Main Results:

• Iodothyronines (T4, T3, T2) enhance cardiac systolic and diastolic function and heart rate.
• Thyronamines (T0AM, T1AM) exhibit negative inotropic and chronotropic effects, potentially acting as a brake on THs.
• Thyronamines demonstrate cardioprotective effects at physiological concentrations; cardiac roles of iodothyroacetic acids require further investigation.

Conclusions:

• Thyroid hormone derivatives exert diverse effects on cardiac function via multiple mechanisms.
• Thyronamines may play a regulatory role in cardiac function and offer cardioprotection.
• Further research is needed to fully elucidate the cardiac impact of iodothyroacetic acids.