A non-selective endothelin receptor antagonist bosentan modulates kinetics of bone marrow-derived cells in ameliorating pulmonary hypertension in mice.

The aim of this study was to investigate whether a dual endothelin receptor antagonist bosentan modulates the kinetics of bone marrow-derived stem cells in inhibiting the development of pulmonary hypertension. Bone marrow chimeric mice, transplanted with enhanced green fluorescent protein (eGFP)-positive bone marrow mononuclear cells, were exposed to hypobaric hypoxia or kept in the ambient air, and were daily treated with bosentan sodium salt or saline for 21 days. After the treatment period, right ventricular pressure was measured and pulmonary vascular morphometry was conducted. Incorporation of bone marrow-derived cells was analyzed by immunohistochemistry. Gene expression and protein level in the lung tissue were evaluated by quantitative real-time PCR and western blotting, respectively. The results showed that, in hypoxic mice, right ventricular pressure and the percentage of muscularized vessel were increased and pulmonary vascular density was decreased, each of which was reversed by bosentan. Bone marrow-derived endothelial cells and macrophages in lungs were increased by hypoxia. Bosentan promoted bone marrow-derived endothelial cell incorporation but inhibited macrophage infiltration into lungs. Quantitative real-time PCR analysis revealed that interleukin 6, stromal cell-derived factor-1, and monocyte chemoattractant protein-1 were upregulated by hypoxia, in which interleukin 6 and monocyte chemoattractant protein-1 were downregulated and stromal cell-derived factor-1 was upregulated by bosentan. Protein level of endothelial nitric oxide synthase (eNOS) in the whole lung was significantly upregulated by hypoxia, which was further upregulated by bosentan. Bosentan modulated kinetics of bone marrow-derived ECs and macrophages and related gene expression in lungs in ameliorating pulmonary hypertension in mice. Altered kinetics of bone marrow-derived stem cells may be a novel mechanism of the endothelin receptor blockade in vivo and confer a new understanding of the therapeutic basis for pulmonary hypertension.

In vivo plaque composition and morphology in coronary artery lesions in adolescents and young adults long after Kawasaki disease: a virtual histology-intravascular ultrasound study.

BACKGROUND: Coronary artery lesions (CALs) late after Kawasaki disease were characterized by endothelial dysfunction and low-grade inflammation, surrogate markers for atherosclerosis. We tested the hypothesis that CALs in patients long after Kawasaki disease are accompanied by atheroma-like features, as assessed by virtual histology-intravascular ultrasound, a new method to assess coronary plaque composition and morphology in vivo. METHODS AND RESULTS: Virtual histology-intravascular ultrasound was performed in 13 Japanese Kawasaki disease patients (median age, 18.3 years; interquartile range, 16.9 to 23.3 years) an interval after Kawasaki disease (median, 15.9 years; interquartile range, 14.3 to 21.9 years). We investigated 6 sites with localized stenosis, 15 sites with an aneurysm, 29 sites with a regressed aneurysm, and 50 sites with a normal coronary segment. Plaque components were categorized into 4 parts: fibrous, fibrofatty, necrotic core, and dense calcium areas. Qualitatively, the normal segment had no or trivial intravascular ultrasound-visible plaque area, whereas the CAL exhibited a heterogeneous plaque area with the 4 components in different amounts and proportions. Quantitatively, a combined group of CALs had a higher absolute value of fibrous, dense calcium, and necrotic core areas than the normal segment. In further analyses of 3 subtypes of CALs, localized stenosis, an advanced lesion, exhibited higher absolute and relative values of dense calcium and necrotic core areas and a lower relative value of the fibrous area than regressed and persistent aneurysms. CONCLUSIONS: The present limited but initial virtual histology-intravascular ultrasound findings give new insight into the potential role of atherogenesis in the evolution of CALs in adolescents and young adults long after Kawasaki disease and therefore warrant further investigation.

A nuclear factor-kappaB inhibitor pyrrolidine dithiocarbamate ameliorates pulmonary hypertension in rats.

BACKGROUND: Pulmonary hypertension (PH) is a fatal disorder that is associated with structural changes and inflammatory responses in the pulmonary vasculature. Nuclear factor (NF)-kappaB is a key transcription factor that is involved in the tissue remodeling mediated by inflammatory and fibroproliferative responses. However, the contribution of NF-kappaB-mediated inflammatory pathways to the development of PH is unknown. METHODS: We therefore investigated whether NF-kappaB activation and the expression of a downstream product vascular cell adhesion molecule (VCAM)-1 is associated with pulmonary vascular diseases in rats that have been injected with the toxin monocrotaline (MCT), and whether a NF-kappaB inhibitor, pyrrolidine dithiocarbamate (PDTC), ameliorates such diseases in rats. RESULTS: VCAM-1 expression and the nuclear localization of the p65 subunit of NF-kappaB, as analyzed immunohistochemically, was significantly up-regulated in the endothelium of diseased vessels on the days 8 to 22 (p < 0.05). Next, 39 rats were divided into three groups (rats injected with MCT and treated with saline solution or PDTC, and controls similarly treated with saline solution). Compared to controls, MCT treatment increased the mean (+/- SE) pulmonary artery pressure (31.2 +/- 1.4 mm Hg [p < 0.05] vs 22.8 +/- 0.9 mm Hg, respectively), which was reduced by PDTC treatment (24.3 +/- 1.2 mm Hg; p < 0.05). Indexes of right ventricular hypertrophy and pulmonary vascular diseases induced by MCT were similarly inhibited (p < 0.05), which was associated with the suppression of VCAM-1 expression and macrophage infiltration. CONCLUSIONS: We concluded that the NF-kappaB nuclear localization and VCAM-1 expression is temporally and spatially associated with the development of MCT-induced PH in rats, which was ameliorated by administering a NF-kappaB inhibitor, PDTC.