Is the vascular system a main target for thyroid hormones? From molecular and biochemical findings to clinical...

Area of Science:

• Endocrinology
• Cardiovascular Biology
• Molecular Medicine

Background:

• Thyroid hormones (THs) are crucial for cardiovascular health, but their direct vascular effects are less understood than their cardiac actions.
• Previous knowledge relied on THs' effects during excess or deficiency, often indirectly impacting vasculature via thermogenic or hemodynamic changes.
• Recent advances clarify THs' molecular and nuclear actions, prompting a deeper look into their direct vascular mechanisms.

Purpose of the Study:

• To elucidate the direct role of thyroid hormones (THs) in vascular system regulation.
• To identify key factors, imbalances, and pathophysiological links in TH-mediated vascular function.
• To explore potential therapeutic strategies targeting TH action in vasculature.

Main Methods:

• Review of existing literature on thyroid hormone action in the vasculature.
• Focus on iodothyronine deiodinases, particularly D2, for local conversion of thyroxine (T4) to triiodothyronine (T3).
• Analysis of deiodinase tissue distribution, localization, structure-activity, and physiological roles.

Main Results:

• Thyroid hormones (THs) exert direct regulatory effects on vascular function.
• Deiodinase enzymes, especially D2, are key in generating locally active T3 within the vasculature.
• Understanding these mechanisms reveals links to vascular pathophysiology.

Conclusions:

• Thyroid hormones (THs) have a direct, significant role in regulating vascular function.
• Deiodinases, particularly D2, are critical for local TH bioavailability and vascular homeostasis.
• Targeting deiodinases offers promising therapeutic avenues for vascular diseases.