TY - JOUR
TI - Hyperthyroid hearts display a phenotype of cardioprotection against ischemic stress: A possible involvement of heat shock protein 70
AU - Pantos, C.
AU - Malliopoulou, V.
AU - Mourouzis, I.
AU - Thempeyioti, A.
AU - Paizis, I.
AU - Dimopoulos, A.
AU - Saranteas, T.
AU - Xinaris, C.
AU - Cokkinos, D.V.
JO - Hormone and Metabolic Research
PY - 2006
VL - 38
TODO - 5
SP - 308-313
PB - 
SN - 0018-5043, 1439-4286
TODO - 10.1055/s-2006-925404
TODO - heat shock protein 70;  levothyroxine;  malonaldehyde;  thyroid hormone, animal cell;  animal experiment;  animal model;  animal tissue;  article;  cell survival;  controlled study;  convalescence;  heart function;  heart muscle;  heart protection;  heart ventricle hypertrophy;  heat stress;  hormone determination;  hyperthyroidism;  ischemic heart disease;  male;  nonhuman;  oxidative stress;  phenotype;  polyacrylamide gel electrophoresis;  priority journal;  protein expression;  reperfusion;  signal transduction;  thyroid hormone blood level, Animals;  Cardiomegaly;  Cell Survival;  Heart;  HSP70 Heat-Shock Proteins;  Hyperthyroidism;  Male;  Malondialdehyde;  Myocardial Contraction;  Myocardial Ischemia;  Myocardium;  Oxidation-Reduction;  Phenotype;  Rats;  Rats, Wistar;  Thyroxine;  Triiodothyronine, Animalia
TODO - Hyperthyroid hearts are shown to display a phenotype of cardioprotection against ischemic stress, but the underlying signaling mechanisms remain largely unknown. The present study investigated the possible relation of HSP70 to the thyroid hormone induced cardioprotection. HSP70 is a redox-regulated molecular chaperone, and enhances cell survival under stress. Thyroxin (25 pg/100g body weight) was administered to Wistar male rats for four days (THYR-4d) and two weeks (THYR-14d), respectively, while untreated animals served as controls (CON-4d, CON-14d). Isolated hearts from control and thyroxin treated rats were subjected to 20 min zero-flow ischemia followed by 45 min of reperfusion (I/R). The amount of HSP70 in the myocardium for THYR-14d was 1.85 times the levels of CON-14d (p < 0.05). The levels of HSP70 expression were no different between THYR-4d and CON-4d, p > 0.05. This was only accompanied by an increase in MDA levels (used as an index of oxidative stress) in THYR-14d compared to untreated hearts. These changes corresponded to a differential response of the heart to I/R; post-ischemic recovery of function was significantly increased in THYR-14d compared to CON-14d, and was no different between the THYR-4d and CON-4d hearts. In conclusion, long-term thyroxin administration results in increased tolerance of the myocardium to I/R and enhances the expression of HSP70 which may, at least in part, account for this response. © Georg Thieme Verlag KG Stuttgart.
ER -