Abstract-Estrogen has been demonstrated to promote therapeutic reendothelialization after vascular injury by bone marrow (BM)-derived endothelial progenitor cell (EPC) mobilization and phenotypic modulation. We investigated the primary hypothesis that estrogen regulates physiological postnatal vasculogenesis by modulating bioactivity of BMderived EPCs through the estrogen receptor (ER), in cyclic hormonally regulated endometrial neovascularization. Cultured human EPCs from peripheral blood mononuclear cells (PB-MNCs) disclosed consistent gene expression of ER ␣ as well as downregulated gene expressions of ER ␤. Under the physiological concentrations of estrogen (17␤-estradiol, E2), proliferation and migration were stimulated, whereas apoptosis was inhibited on day 7 cultured EPCs. These estrogen-induced activities were blocked by the receptor antagonist, ICI182,780 (ICI). In BM transplanted (BMT) mice with ovariectomy (OVX) from transgenic mice overexpressing ␤-galactosidase (lacZ) regulated by an endothelial specific Tie-2 promoter (Tie-2/lacZ/BM), the uterus demonstrated a significant increase in BM-derived EPCs (lacZ expressing cells) incorporated into neovasculatures detected by CD31 immunohistochemistry after E2 administration. The BM-derived EPCs that were incorporated into the uterus dominantly expressed ER ␣, rather than ER ␤ in BMT mice from BM of transgenic mice overexpressing EGFP regulated by Tie-2 promoter with OVX (Tie-2/EGFP/BMT/OVX) by ERs fluorescence immunohistochemistry. An in vitro assay for colony forming activity as well as flow cytometry for CD133, CD34, KDR, and VE-cadherin, using human PB-MNCs at 5 stages of the female menstrual-cycle (early-proliferative, pre-ovulatory, post-ovulatory, mid-luteal, late-luteal), revealed cycle-specific regulation of EPC kinetics. These findings demonstrate that physiological postnatal vasculogenesis involves cyclic, E2-regulated bioactivity of BM-derived EPCs, predominantly through the ER␣. (Circ Res. 2007;101:598-606.)Key Words: estrogen Ⅲ endothelial progenitor cell Ⅲ estrogen receptor Ⅲ physiological postnatal vasculogenesis I n the female reproductive system, neovascularization is a recurring phenomemnon controlled by cyclic development of transient structure and cyclical repair of damaged tissue. 1 The ovarian sex steroid hormones, estrogen and progesterone, are primarily uterotropic and control the cyclical patterns of uterine cell proliferation and vascular growth that occur throughout the nonpregnant menstrual cycle. Given the synchronized nature of neovascularization in this cyclical mannter, it is assumed that angiogenic growth factor expression is induced by steroid hormones and regulates blood vessel formation in reproductive organogenesis. [2][3][4][5] Despite clinical evidence for the significant role of steroid hormones in endometrial neovascularization, further investigation using in vitro and in vivo experiments have yielded inconclusive results regarding pathophysiological mechanisms in angiogenesis. 6 -10 Moreover, estrogen has been sh...

Nicotine has been demonstrated to stimulate postnatal angiogenesis, having an antiapoptotic effect on endothelial cells. Given the extent of this angiogenesis-promoting effect, we hypothesized that nicotine may also stimulate postnatal vasculogenesis on endothelial progenitor cells (EPCs). Our analyses reveal some intriguing results using an in vitro assay with 2 x 10(-6) M of nicotine (smoker's average nicotine concentration and the dose of nicotine replacement therapy). The proliferation and migration activities of human EPCs cultured from peripheral blood mononuclear cells of non-smoking healthy volunteers were not affected by nicotine. The effect of nicotine on EPC survival was significantly enhanced under serum starvation on the ratio of Hoechest 33342-stained pyknotic nuclear cells as well as Annexin-V-stained cells to total cells. Furthermore, the antiapoptotic effect of nicotine was blocked completely by nicotinic acetylcholine receptor (nAChR) antagonist hexamethonium. Next, we verified how nicotine acts in vivo. Nicotine (100 ng/ml) was administered orally for 7 days before and 4 weeks after injection of cultured EPCs (1 x 10(5) /mouse) into the tail veins of 8-week-old athymic nude mice with ischemic hindlimbs. Laser doppler imaging analysis indicated that blood perfusion in the ischemic hindlimb was significantly enhanced in EPCs plus nicotine, as compared with EPCs alone. These findings suggest nicotine improves blood flow following EPC transplantation in patients with ischemic diseases.

ifekalant hydrochloride (NIF) is the first class III anti-arrhythmic agent for intravenous use covered by National Health Insurance in Japan for refractory ventricular tachycardia and fibrillation (VT/VF). NIF blocks the delayed rectifier K + channels, especially the IKr channels. NIF also has some potential to block the inward rectifier K + current IK1 and transient outward K + channel Ito. Thus it prolongs the action potential duration (APD) and stops VT/VF by extending the refractory period. 1,2 However, amiodarone (AMD) is a known K-channel blocker that also has Na blocking action and blocking action. The properties of NIF differ greatly from those of AMD.In 1999, our coworkers Tanabe et al investigated the effect of NIF (MS-551) on the effective refractory period (ERP) in the epicardium and endocardium in a canine model of acute myocardial infarction (AMI), and reported that NIF significantly prolonged the ERP in both the normal zone (NZ) and ischemic zone (IZ) of the ischemic myocardium; however, the dispersion of the ERP in the epicardium and endocardium increased in the NZ but decreased in the IZ. 3 Recently, our coworkers Amino et al conducted a comparative investigation of the 90% APD (APD90) prolonging effect of NIF on the surface of the left ventricle (LV) and APD90 dispersion (APDD) in isolated perfused rabbit hearts at basic cycle lengths (BCLs) of 400 ms and 250 ms. APD90 was prolonged with the efficacy of a reverse use dependent block without increasing the APDD at either BCL, and as a result NIF decreased VT/VF vulnerability. 4 These study results suggest that NIF may stop VT/VF by improving epicardial surface and transmural dispersion of repolarization (TDR) in the LV, in addition to its refractory-period-prolonging action.In a clinical study, we used NIF to treat lidocaine-resistant VT/VF in patients with out-of-hospital cardiopulmonary arrest (OHCPA), and reported that it exerted excellent anti-arrhythmic efficacy. 5 In a study in which we compared OHCPA patients with acidosis and in-hospital cardiopulmonary arrest (IHCPA) patients without acidosis, NIF was Background Because nifekalant hydrochloride (NIF) displayed a superior defibrillating effect on ventricular tachycardia/fibrillation (VT/VF) in cardiopulmonary arrest (CPA) patients, despite some QT prolongation, its effect on transmural dispersion of repolarization (TDR) in the left ventricle (LV) in an animal model of CPA was investigated. Methods and ResultsEight beagle dogs were created with a myocardial infarction under anesthesia, and then VT/VF induction by continuous stimulation and cardiopulmonary resuscitation (CPR) were repeated. NIF (0.3 mg/kg) was administered under acidotic conditions (pH 7.26). The QTc interval measured by Y-lead ECG showed no significant prolongation before and after NIF. The activation recovery interval (ARI) measured by 64-lead LV surface mapping showed minimum ARI prolongation (40%) by NIF without maximum ARI prolongation, and as a result the ARI dispersion decreased by 67%. The repolarization time (RPT)...

No abstract