| First Author | Suarez J | Year | 2014 |
| Journal | Am J Physiol Regul Integr Comp Physiol | Volume | 307 |
| Issue | 3 | Pages | R340-6 |
| PubMed ID | 24848360 | Mgi Jnum | J:240916 |
| Mgi Id | MGI:5896721 | Doi | 10.1152/ajpregu.00449.2013 |
| Citation | Suarez J, et al. (2014) In vivo selective expression of thyroid hormone receptor alpha1 in endothelial cells attenuates myocardial injury in experimental myocardial infarction in mice. Am J Physiol Regul Integr Comp Physiol 307(3):R340-6 |
| abstractText | Ischemic heart disease (IHD) is the single most common cause of death. New approaches to enhance myocardial perfusion are needed to improve outcomes for patients with IHD. Thyroid hormones (TH) are known to increase blood flow; however, their usefulness for increasing perfusion in IHD is limited because TH accelerates heart rate, which can be detrimental. Therefore, selective activation of TH effects is desirable. We hypothesized that cell-type-specific TH receptor (TR) expression can increase TH action in the heart, while avoiding the negative consequences of TH treatment. We generated a binary transgenic (BTG) mouse that selectively expresses TRalpha1 in endothelial cells in a tetracycline-inducible fashion. In BTG mice, endothelial TRalpha1 protein expression was increased by twofold, which, in turn, increased coronary blood flow by 77%, coronary conductance by 60%, and coronary reserve by 47% compared with wild-type mice. Systemic blood pressure was decreased by 20% in BTG mice after TRalpha1 expression. No effects on heart rate were observed. Endothelial TRalpha1 expression activated AKT/endothelial nitric oxide synthase pathway and increased A2AR adenosine receptor. Furthermore, hearts from BTG mice overexpressing TRalpha1 that were submitted to 20 min ischemia and 20 min reperfusion showed a 20% decline in left ventricular pressure (LVP) compared with control mice where LVP was decreased by 42%. Studies using an infarction mouse model demonstrated that endothelial overexpression of TRalpha1 decreased infarct size by 45%. In conclusion, selective expression of TRalpha1 in endothelial cells protects the heart against injury after an ischemic insult and does not result in adverse cardiac or systemic effects. |
