Lance P Christensen

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Previous studies from our laboratory and those of others have shown thyroxine to be a stimulator of coronary microvascular growth. The present study tested the hypothesis that 3,5-diiodothyropropionic acid (DITPA), a thyroid hormone analog with inotropic but not chronotopic characteristics, is angiogenic in the nonischemic heart. Daily injections (3.75(More)
Mechanical stretch, an important growth stimulus, results not only from pulsatile blood flow and diastolic stretch of the ventricles [cyclic stretch (CS)] but also from tissue expansion during growth [constant static stretch (SS)]. We compared growth factor receptor expression and vasculogenic/angiogenic responses of rat coronary microvascular endothelial(More)
We tested the hypothesis that chronically reducing the heart rate in infarcted middle-aged rats using ivabradine (IVA) would induce arteriolar growth and attenuate perivascular collagen and, thereby, improve maximal perfusion and coronary reserve in the surviving myocardium. Myocardial infarction (MI) was induced in 12-mo-old male Sprague-Dawley rats, which(More)
An increasing body of evidence indicates that left ventricular (LV) remodeling, especially the degree of reactive myocardial hypertrophy after myocardial infarction (MI), differs in males and females. Surprisingly, to date, the sex-specific post-MI alterations of the coronary vasculature remain undetermined. Therefore, we tested the hypothesis that adaptive(More)
BACKGROUND We tested the hypothesis that induction of chronic bradycardia would trigger an upregulation of key growth factors and receptors, which would then lead to angiogenesis and improve coronary reserve in the left ventricle after myocardial infarction. METHODS AND RESULTS Bradycardia was induced in rats by administering alinidine via osmotic pumps(More)
In embryonic hearts explanted on collagen gels, epicardial cells delaminate and form vascular tubes, thus providing a model for coronary tubulogenesis. Using this model, we show that fibroblast growth factors (FGFs) 1, 2, 4, 8, 9, and 18 contribute to tubulogenesis and that the availability of multiple FGFs provides the optimal tubulogenic response.(More)
We previously demonstrated that cyclic stretch of cardiac myocytes activates paracrine signaling via vascular endothelial growth factor (VEGF) leading to angiogenesis. The present study tested the hypothesis that cyclic stretch upregulates tyrosine kinase receptors in rat coronary microvascular endothelial cells (RCMEC) and human umbilical vein endothelial(More)
OBJECTIVE PDGF and FGF-2 are important regulators of vascular wall assembly. We tested the hypothesis that their embryonic temporal expression facilitates 2 specific events: (1) the endothelial invasion of the aortic root to form the coronary artery stems and (2) the subsequent growth and development of the arterial tree. METHODS AND RESULTS Addition of(More)
Estrogen increases proliferation and migration of cultured endothelial cells and perfusion of ischemic hindlimbs of rabbits. We tested the hypothesis that estrogen is angiogenic and arteriogenic in the heart during progressive coronary occlusion. Ovariectomized (OVX) and 17beta-estradiol (1 mg.kg(-1).wk(-1) im)-treated OVX (OVX-ES) female New Zealand White(More)
We compared the effects of heart rate reduction (HRR) by the hyperpolarization-activated pacemaker current (I(f)) channel inhibitor ivabradine (MI+Iva) and the beta(1)-blocker atenolol (MI+Aten) on ventricular remodeling and perfusion after myocardial infarction (MI) in middle-aged (12 mo) Sprague-Dawley rats. Mean HRR was virtually identical in the two(More)