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In vitro Assessment of Myocardial Protection following Hypothermia-Preconditioning in a Human Cardiac Myocytes Model
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In vitro Assessment of Myocardial Protection following Hypothermia-Preconditioning in a Human Cardiac Myocytes Model

Published on: October 27, 2020

Hyperthyroid hearts display a phenotype of cardioprotection against ischemic stress: a possible involvement of heat

C Pantos1, V Malliopoulou, I Mourouzis

  • 1Department of Pharmacology, University of Athens. cpantos@cc.uoa.gr

Hormone and Metabolic Research = Hormon- Und Stoffwechselforschung = Hormones Et Metabolisme
|May 24, 2006
PubMed

Insights

Long-term thyroxin treatment enhances heart protection against ischemic stress by increasing Heat Shock Protein 70 (HSP70) expression. This suggests HSP70 plays a key role in thyroid hormone-induced cardioprotection.

Area of Science:

  • Cardiovascular Physiology
  • Molecular Biology
  • Endocrinology

Background:

  • Hyperthyroid hearts exhibit cardioprotection against ischemia, but mechanisms are unclear.
  • Heat Shock Protein 70 (HSP70) is a stress-responsive chaperone enhancing cell survival.
  • Thyroid hormones may influence myocardial stress resilience via HSP70.

Purpose of the Study:

  • To investigate the relationship between HSP70 and thyroid hormone-induced cardioprotection.
  • To determine if long-term thyroxin administration alters HSP70 expression and myocardial tolerance to ischemia/reperfusion (I/R).

Main Methods:

  • Wistar rats received thyroxin for 4 or 14 days.
  • Isolated hearts underwent 20 min ischemia followed by 45 min reperfusion (I/R).
  • Myocardial HSP70 levels and oxidative stress (MDA) were measured; functional recovery post-I/R was assessed.

Main Results:

  • Long-term (14-day) thyroxin treatment significantly increased myocardial HSP70 levels (1.85-fold) compared to controls.
  • Short-term (4-day) thyroxin treatment did not alter HSP70 levels.
  • Hearts from long-term treated rats showed significantly improved functional recovery after I/R, unlike short-term treated hearts.
  • Increased oxidative stress (MDA) was noted in long-term treated hearts.

Conclusions:

  • Long-term thyroxin administration confers myocardial tolerance to I/R.
  • Enhanced HSP70 expression in the myocardium likely contributes to this cardioprotective effect.
  • Thyroid hormone-induced cardioprotection is time-dependent and associated with HSP70 upregulation.

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