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Effects of T3 (Tri‐iodothyronine) on Myocardial Remodeling and Functional Recovery After Ischemia/Reperfusion
Author(s) -
Seitter S.,
Pol C,
Rajagopalan V.,
Zhang Y.,
Chen Y.,
Gerdes A M
Publication year - 2015
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.29.1_supplement.798.2
Subject(s) - medicine , cardiology , ventricular remodeling , myocardial infarction , heart failure , left coronary artery , ischemia , cardiac function curve , hemodynamics
Despite treatment advances, many patients develop heart failure (HF) after myocardial infarction (MI) and ischemia/reperfusion (I/R). It is known that MI triggers reduced cardiac thyroid hormone (TH) levels. Hypothyroidism alone can also lead to dilated HF with a maladaptive change in myocyte shape and impaired coronary blood flow. We hypothesize that T3 treatment of ischemia with reperfusion of the culprit artery will lead to improvements in infarct remodeling and myocardial function. Methods: 52 Adult rats underwent surgery to occlude the left anterior descending coronary artery for one hour. After one hour, the suture was released and the chest closed. Shams were done similarly but without ligation. Oral T3 (8μg/Kg/day) or placebo treatment was started right after surgery. Left ventricular function and remodeling were assessed by echocardiography and hemodynamics (Millar catheter) after 2 months. Hearts were removed, weighed, and sliced for fixation in formalin for paraffin embedding or frozen in liquid nitrogen for analysis. Results: Compared to shams, I/R resulted in infarcted area of 20±5% in the untreated group and 17±6% in the T3 treated group, leading to a 14% increase in viable myocardium. I/R rats showed reduced fractional shortening and maximal rate of LV pressure development (+dP/dtmax). T3 treated I/R rats showed normalized +dP/dtmax. In I/R, diastolic function was impaired as shown by increased Tau and reduced maximal rate of pressure decline (‐dP/dtmin), with improvement in the T3 treated group. Conclusion Reperfusion is known to increase survival of myocardium post‐MI. Our results suggest further improvements in contractility, relaxation, and viable myocardium after low dose T3 in I/R. Supported by NIH grant RO1HL103671