[Intrathoracic washing with urokinase was effective for empyema with atelectasis].

A 60-year-old man had a medical examination because of fever in the emergency hospital and had a diagnosis of pneumonia and was treated, but he was admitted to our hospital 2 days later because there was not the improvement of his symptom. The chest computed tomography(CT)image showed multilocular pleural effusions and lower lobe atelectasis with the air bronchogram on the left side. We diagnosed the case as empyema and inserted a catheter, but drainage was very few and injected 60,000 urokinase units for 3 days from the next day. We removed a drain 2 days after the 3rd infusion, and the pleural thickening became mild, and atelectasis was gradually improved in the chest CT image, and the inflammatory reaction was reduced, too. The intrathoracic washing with urokinase was thought to be effective for empyema with atelectasis.

Elevated circulating plasma adiponectin in underweight patients with COPD.

BACKGROUND: Adiponectin is an adipose tissue-derived specific protein that has antiinflammatory as well as anti-atherosclerotic effects. In the United States, many patients with COPD are obese and die of cardiovascular diseases. However, in Japan, patients with COPD are frequently cachexic and die of respiratory failure. This study was designed to investigate the role of adiponectin in these differences in characteristics of COPD. METHODS: We enrolled normal-weight and underweight male patients with COPD (n = 31; age, 71 +/- 1 years; body mass index [BMI], 20.1 +/- 0.6 kg/m(2)) and age-matched, healthy, male, control subjects (n = 12). The adiponectin levels were measured by enzyme-linked immunosorbent assay. Correlation of adiponectin levels with pulmonary function and serum levels of proinflammatory cytokines (tumor necrosis factor [TNF]-alpha and interleukin-6) were estimated. RESULTS: Adiponectin levels in patients with COPD were significantly higher than those in control subjects (p<0.01) and inversely correlated with BMI (r = - 0.55, p<0.01). Even in the normal-weight patients with COPD, adiponectin levels were significantly higher than those in control subjects (p<0.01). Adiponectin levels in patients with COPD significantly correlated with percentage of predicted residual volume (r = 0.40, p<0.05). In patients with TNF-alpha levels > 5 pg/mL, there was a significant correlation between plasma adiponectin and serum TNF-alpha levels (r = 0.68, p<0.05). CONCLUSIONS: Plasma adiponectin levels in patients with COPD were elevated and correlated with body weight loss, hyperinflation, and systemic inflammation. Increased adiponectin may reduce cardiovascular events in underweight patients with COPD.

Transplantation of mesenchymal stem cells improves cardiac function in a rat model of dilated cardiomyopathy.

BACKGROUND: Pluripotent mesenchymal stem cells (MSCs) differentiate into a variety of cells, including cardiomyocytes and vascular endothelial cells. However, little information is available about the therapeutic potency of MSC transplantation in cases of dilated cardiomyopathy (DCM), an important cause of heart failure. METHODS AND RESULTS: We investigated whether transplanted MSCs induce myogenesis and angiogenesis and improve cardiac function in a rat model of DCM. MSCs were isolated from bone marrow aspirates of isogenic adult rats and expanded ex vivo. Cultured MSCs secreted large amounts of the angiogenic, antiapoptotic, and mitogenic factors vascular endothelial growth factor, hepatocyte growth factor, adrenomedullin, and insulin-like growth factor-1. Five weeks after immunization, MSCs or vehicle was injected into the myocardium. Some engrafted MSCs were positive for the cardiac markers desmin, cardiac troponin T, and connexin-43, whereas others formed vascular structures and were positive for von Willebrand factor or smooth muscle actin. Compared with vehicle injection, MSC transplantation significantly increased capillary density and decreased the collagen volume fraction in the myocardium, resulting in decreased left ventricular end-diastolic pressure (11+/-1 versus 16+/-1 mm Hg, P<0.05) and increased left ventricular maximum dP/dt (6767+/-323 versus 5138+/-280 mm Hg/s, P<0.05). CONCLUSIONS: MSC transplantation improved cardiac function in a rat model of DCM, possibly through induction of myogenesis and angiogenesis, as well as by inhibition of myocardial fibrosis. The beneficial effects of MSCs might be mediated not only by their differentiation into cardiomyocytes and vascular cells but also by their ability to supply large amounts of angiogenic, antiapoptotic, and mitogenic factors.

Adrenomedullin enhances angiogenic potency of bone marrow transplantation in a rat model of hindlimb ischemia.

BACKGROUND: Previous studies have shown that adrenomedullin (AM) inhibits vascular endothelial cell apoptosis and induces angiogenesis. We investigated whether AM enhances bone marrow cell-induced angiogenesis. METHODS AND RESULTS: Immediately after hindlimb ischemia was created, rats were randomized to receive AM infusion plus bone marrow-derived mononuclear cell (MNC) transplantation (AM+MNC group), AM infusion alone (AM group), MNC transplantation alone (MNC group), or vehicle infusion (control group). The laser Doppler perfusion index was significantly higher in the AM and MNC groups than in the control group (0.74+/-0.11 and 0.69+/-0.07 versus 0.59+/-0.07, respectively, P<0.01), which suggests the angiogenic potency of AM and MNC. Importantly, improvement in blood perfusion was marked in the AM+MNC group (0.84+/-0.08). Capillary density was highest in the AM+MNC group, followed by the AM and MNC groups. In vitro, AM inhibited MNC apoptosis, promoted MNC adhesiveness to a human umbilical vein endothelial cell monolayer, and increased the number of MNC-derived endothelial progenitor cells. In vivo, AM administration not only enhanced the differentiation of MNC into endothelial cells but also produced mature vessels that included smooth muscle cells. CONCLUSIONS: A combination of AM infusion and MNC transplantation caused significantly greater improvement in hindlimb ischemia than MNC transplantation alone. This effect may be mediated in part by the angiogenic potency of AM itself and the beneficial effects of AM on the survival, adhesion, and differentiation of transplanted MNCs.

Comparison of angiogenic potency between mesenchymal stem cells and mononuclear cells in a rat model of hindlimb ischemia.

OBJECTIVE: Mesenchymal stem cells (MSC) are pluripotent cells that differentiate into a variety of cells including endothelial cells and vascular smooth muscle cells. Although transplantation of bone marrow-derived mononuclear cells (MNC) has already been applied for the treatment of critical limb ischemia, little information is available regarding comparison of the angiogenic potency between MSC and MNC. Accordingly, we injected equal numbers of MSC or MNC in a rat model of hindlimb ischemia and compared their therapeutic potential. METHODS AND RESULTS: Immediately after creating hindlimb ischemia, rats were randomized to receive MSC transplantation (MSC group), MNC transplantation (MNC group), or vehicle infusion (Control group). Three weeks after transplantation, the laser Doppler perfusion index was significantly higher in the MNC group than in the Control group (0.69+/-0.1 vs. 0.57+/-0.06, P<0.01). Furthermore, there was a marked improvement in blood perfusion in the MSC group (0.81+/-0.08). Capillary density was highest in the MSC group. The number of transplanted cell-derived endothelial cells was higher in the MSC group than in the MNC group. Transplanted cell-derived vascular smooth muscle cells were detected only in the MSC group. In vitro, MSC were more tolerant to apoptotic stimulus (serum starvation and hypoxia) than MNC. CONCLUSIONS: MSC transplantation caused significantly greater improvement in hindlimb ischemia than MNC transplantation. Compared with MNC, MSC survived well under an ischemic environment, and differentiated into not only endothelial cells but also vascular smooth muscle cells. Thus, MSC transplantation may be a new therapeutic strategy for the treatment of severe peripheral vascular disease.

Adrenomedullin infusion attenuates myocardial ischemia/reperfusion injury through the phosphatidylinositol 3-kinase/Akt-dependent pathway.

BACKGROUND: Infusion of adrenomedullin (AM) has beneficial hemodynamic effects in patients with heart failure. However, the effect of AM on myocardial ischemia/reperfusion remains unknown. METHODS AND RESULTS: Male Sprague-Dawley rats were exposed to a 30-minute period of ischemia induced by ligation of the left coronary artery. They were randomized to receive AM, AM plus wortmannin (a phosphatidylinositol 3-kinase [PI3K] inhibitor), or saline for 60 minutes after coronary ligation. Hemodynamics and infarct size were examined 24 hours after reperfusion. Myocardial apoptosis was also examined 6 hours after reperfusion. The effect of AM on Akt phosphorylation in cardiac tissues was examined by Western blotting. Intravenous administration of AM significantly reduced myocardial infarct size (28+/-4% to 16+/-1%, P<0.01), left ventricular end-diastolic pressure (19+/-2 to 8+/-2 mm Hg, P<0.05), and myocardial apoptotic death (19+/-2% to 9+/-4%, P<0.05). Western blot analysis showed that AM infusion accelerated Akt phosphorylation in cardiac tissues and that pretreatment with wortmannin significantly attenuated AM-induced Akt phosphorylation. Moreover, pretreatment with wortmannin abolished the beneficial effects of AM: a reduction of infarct size, a decrease in left ventricular end-diastolic pressure, and inhibition of myocardial apoptosis after ischemia/reperfusion. CONCLUSIONS: Short-term infusion of AM significantly attenuated myocardial ischemia/reperfusion injury. These cardioprotective effects are attributed mainly to antiapoptotic effects of AM via a PI3K/Akt-dependent pathway.

Adrenomedullin enhances therapeutic potency of mesenchymal stem cells after experimental stroke in rats.

BACKGROUND AND PURPOSE: Adrenomedullin (AM) induces angiogenesis and inhibits cell apoptosis through the phosphatidylinositol 3-kinase/Akt pathway. Transplantation of mesenchymal stem cells (MSCs) has been shown to improve neurological deficits after stroke in rats. We investigated whether AM enhances the therapeutic potency of MSC transplantation. METHODS: Male Lewis rats (n=100) were subjected to 2-hour middle cerebral artery occlusion. Immediately after reperfusion, rats were assigned randomly to receive intravenous transplantation of MSCs plus subcutaneous infusion of AM for 7 days (MSC+AM group), AM infusion alone (AM group), MSC transplantation alone (MSC group), or vehicle infusion (control group). Neurological and immunohistological assessments were performed to examine the effects of these treatments. RESULTS: Some engrafted MSCs were positive for neuronal and endothelial cell markers, although the number of differentiated MSCs did not differ significantly between the MSC and MSC+AM groups. The neurological score significantly improved in the MSC, AM, and MSC+AM groups compared with the control group. Importantly, improvement in the MSC+AM group was significantly greater than that in the MSC and AM groups. There was marked induction of angiogenesis in the ischemic penumbra in the MSC+AM group, followed by the AM, MSC, and control groups. AM infusion significantly inhibited apoptosis of transplanted MSCs. As a result, the number of engrafted MSCs in the MSC+AM group was significantly higher than that in the MSC group. CONCLUSIONS: AM enhanced the therapeutic potency of MSCs, including neurological improvement, possibly through inhibition of MSC apoptosis and induction of angiogenesis.

Treatment of cachexia with ghrelin in patients with COPD.

STUDY OBJECTIVES: Ghrelin is a novel growth hormone (GH)-releasing peptide that also induces a positive energy balance by decreasing fat utility and stimulating feeding through GH-independent mechanisms. We investigated whether ghrelin improves cachexia and functional capacity in patients with COPD. METHODS: This is an open-label pilot study. Human ghrelin (2 microg/kg bid) was IV administered to seven cachectic patients with COPD for 3 weeks. Food intake, body composition, muscle strength, exercise capacity, pulmonary function, and sympathetic nerve activity were examined before and after ghrelin therapy. RESULTS: A single administration of ghrelin markedly increased serum GH (21-fold). Three-week treatment with ghrelin resulted in a significant increase in mean (+/- SEM) body weight (49.3 +/- 3.6 to 50.3 +/- 3.8 kg; p < 0.05). Food intake was significantly increased during ghrelin therapy. Ghrelin increased lean body mass and peripheral and respiratory muscle strength. Ghrelin significantly increased Karnofsky performance status score and the distance walked in 6 min (370 +/- 30 to 432 +/- 35 m; p < 0.05), although it did not significantly alter pulmonary function. Ghrelin attenuated the exaggerated sympathetic nerve activity, as indicated by a marked decrease in plasma norepinephrine level (889 +/- 123 to 597 +/- 116 pg/mL; p < 0.05). CONCLUSIONS: These preliminary results suggest that repeated administration of ghrelin improves body composition, muscle wasting, functional capacity, and sympathetic augmentation in cachectic patients with COPD.

Acute pulmonary thromboembolism associated with interstitial pneumonia.

A 68-year-old woman, who had been diagnosed as idiopathic interstitial pneumonia, complained of progressive dyspnea on exertion for a week. Although her chest radiograph did not worsen, arterial blood gas findings were markedly worsened. Contrast-enhanced chest computed tomography showed filling defects of the right upper and middle lobe branches of the pulmonary artery. She was diagnosed as having acute pulmonary thromboembolism (APTE). Clinical symptoms and contrast-enhanced chest computed tomography findings were remarkably improved after the treatment with heparin and urokinase. APTE should be considered as a differential diagnosis in patients with interstitial pneumonia who have worsening of respiratory symptoms with unchanged chest radiograph.

Adrenomedullin ameliorates lipopolysaccharide-induced acute lung injury in rats.

Adrenomedullin (AM), an endogenous peptide, has been shown to have a variety of protective effects on the cardiovascular system. However, the effect of AM on acute lung injury remains unknown. Accordingly, we investigated whether AM infusion ameliorates lipopolysaccharide (LPS)-induced acute lung injury in rats. Rats were randomized to receive continuous intravenous infusion of AM (0.1 microg x kg(-1) x min(-1)) or vehicle through a microosmotic pump. The animals were intratracheally injected with either LPS (1 mg/kg) or saline. At 6 and 18 h after intratracheal instillation, we performed histological examination and bronchoalveolar lavage and assessed the lung wet/dry weight ratio as an index of acute lung injury. Then we measured the numbers of total cells and neutrophils and the levels of tumor necrosis factor (TNF)-alpha and cytokine-induced neutrophil chemoattractant (CINC) in bronchoalveolar lavage fluid (BALF). In addition, we evaluated BALF total protein and albumin levels as indexes of lung permeability. LPS instillation caused severe acute lung injury, as indicated by the histological findings and the lung wet/dry weight ratio. However, AM infusion attenuated these LPS-induced abnormalities. AM decreased the numbers of total cells and neutrophils and the levels of TNF-alpha and CINC in BALF. AM also reduced BALF total protein and albumin levels. In addition, AM significantly suppressed apoptosis of alveolar wall cells as indicated by cleaved caspase-3 staining. In conclusion, continuous infusion of AM ameliorated LPS-induced acute lung injury in rats. This beneficial effect of AM on acute lung injury may be mediated by inhibition of inflammation, hyperpermeability, and alveolar wall cell apoptosis.

Increased plasma monocyte chemoattractant protein-1 level in idiopathic pulmonary arterial hypertension.

OBJECTIVE: Monocyte chemoattractant protein-1 (MCP-1), a pro-inflammatory chemokine, has potent chemoattractant activity for monocytes/macrophages. We sought to investigate the clinical significance of MCP-1 in idiopathic pulmonary arterial hypertension (IPAH). METHODS: This study included 28 patients with IPAH, seven patients with pulmonary arterial hypertension (PAH) related to collagen vascular disease, and 13 healthy subjects. Plasma MCP-1 levels were measured together with serum IL-6 and tumour necrosis factor-alpha (TNF-alpha) levels. RESULTS: Circulating levels of MCP-1, IL-6 and TNF-alpha were significantly higher in patients with IPAH than in healthy controls, although they were lower than in patients with PAH related to collagen vascular disease. Plasma MCP-1 did not significantly correlate with any haemodynamic variables. However, plasma MCP-1 levels correlated negatively with the disease duration (time from symptom onset). CONCLUSIONS: Plasma MCP-1 levels were elevated in patients with IPAH, and this elevation was particularly marked in the early stage of disease. Taking into account the chemoattractant activity of MCP-1, these results imply a contribution of MCP-1 to the development of pulmonary hypertension.

Prostacyclin agonist with thromboxane synthase inhibitory activity (ONO-1301) attenuates bleomycin-induced pulmonary fibrosis in mice.

The balance between prostacyclin and thromboxane A2 (TXA2) plays an important role in pulmonary homeostasis. However, little information is available regarding the therapeutic potency of these prostanoids for pulmonary fibrosis. We have recently developed ONO-1301, a novel long-acting prostacyclin agonist with thromboxane synthase inhibitory activity. Thus we investigated whether repeated administration of ONO-1301 attenuates bleomycin-induced pulmonary fibrosis in mice. After intratracheal injection of bleomycin or saline, mice were randomized to receive repeated subcutaneous administration of ONO-1301 or vehicle. Bronchoalveolar lavage (BAL) and histological analyses were performed at 3, 7, and 14 days after bleomycin injection. In vitro studies using mouse lung fibroblasts were also performed. ONO-1301 significantly attenuated the development of bleomycin-induced pulmonary fibrosis, as indicated by significant decreases in Ashcroft score and lung hydroxyproline content. ONO-1301 significantly reduced total cell count, neutrophil count, and total protein level in BAL fluid in association with a marked reduction of TXB2. A single administration of ONO-1301 significantly increased plasma cAMP level for >2 h. In vitro, ONO-1301 and a cAMP analog dose-dependently reduced cell proliferation in mouse lung fibroblasts. The reduction in cell proliferation by ONO-1301 was attenuated by a protein kinase A (PKA) inhibitor. Furthermore, bleomycin mice treated with ONO-1301 had a significantly higher survival rate than those given vehicle. These results suggest that repeated administration of ONO-1301 attenuates the development of bleomycin-induced pulmonary fibrosis and improves survival in bleomycin mice, at least in part by inhibition of TXA2 synthesis and activation of the cAMP/PKA pathway.

Adrenomedullin regenerates alveoli and vasculature in elastase-induced pulmonary emphysema in mice.

RATIONALE: Adrenomedullin, a potent vasodilator peptide, regulates cell growth and survival. However, whether adrenomedullin contributes to lung regeneration remains unknown. OBJECTIVES: To investigate whether adrenomedullin influences the kinetics of bone marrow cells, and whether adrenomedullin promotes regeneration of alveoli and vasculature and thereby improves lung structure and function in elastase-induced emphysema in mice. METHODS: Adrenomedullin or vehicle was randomly administered to C57BL/6 mice for 5 days. We counted the numbers of mononuclear cells and stem cell antigen-1-positive cells in circulating blood. After intratracheal injection of elastase or saline, mice were randomized to receive continuous infusion of adrenomedullin or vehicle for 14 days. Functional and histologic analyses were performed 28 days after treatment. RESULTS: Twenty-eight days after elastase injection, destruction of the alveolar walls was observed. However, adrenomedullin infusion significantly inhibited the increase in lung volume, static lung compliance, and mean linear intercept in mice given elastase. Adrenomedullin increased the numbers of mononuclear cells and stem cell antigen-1-positive cells in circulating blood. Adrenomedullin significantly increased the number of bone marrow-derived cells incorporated into the elastase-treated lung. Some of these cells were positive for cytokeratin or von Willebrand factor. Infusion of adrenomedullin after the establishment of emphysema also had beneficial effects on lung structure and function. In vitro, addition of adrenomedullin attenuates elastase-induced cell death in alveolar epithelial cells and endothelial cells. CONCLUSIONS: Adrenomedullin improved elastase-induced emphysema at least in part through mobilization of bone marrow cells and the direct protective effects on alveolar epithelial cells and endothelial cells.

A long-acting prostacyclin agonist with thromboxane inhibitory activity for pulmonary hypertension.

RATIONALE: The balance between prostacyclin and thromboxane plays an important role in the regulation of pulmonary vascular tone. Recently, we developed ONO-1301, a novel, long-acting prostacyclin agonist with thromboxane synthase inhibitory activity. OBJECTIVES: We investigated whether modulation of prostacyclin/thromboxane balance by ONO-1301 ameliorates monocrotaline-induced pulmonary hypertension in rats. METHODS: After subcutaneous injection of monocrotaline or vehicle, rats were randomized to receive repeated subcutaneous administration of ONO-1301 or vehicle twice per day for 3 wk. MEASUREMENTS AND MAIN RESULTS: There was significant development of pulmonary hypertension 3 wk after monocrotaline injection. Treatment with ONO-1301 significantly attenuated the increases in right ventricular systolic pressure and ratio of right ventricular weight to body weight in monocrotaline rats. Furthermore, ONO-1301 significantly attenuated the increase in medial wall thickness of peripheral pulmonary arteries in monocrotaline rats. The half-life of plasma ONO-1301 concentration after a single subcutaneous administration was approximately 5.6 h. A single administration of ONO-1301 increased plasma cyclic adenosine 3', 5'-monophosphate level, which lasted at least up to 8 h. Treatment with ONO-1301 significantly decreased plasma 11-dehydro-thromboxane B2, a metabolite of thromboxane, in monocrotaline rats. Finally, Kaplan-Meier survival curves demonstrated that repeated administration of ONO-1301 improved survival rate in monocrotaline rats compared with vehicle administration (80 vs. 30% in 6-wk survival). CONCLUSIONS: Subcutaneous administration of a novel prostacyclin agonist (ONO-1301) markedly attenuated monocrotaline-induced pulmonary hypertension and improved survival in rats. The beneficial effects of ONO-1301 may occur through its long-lasting stimulation of cyclic adenosine 3', 5'-monophosphate and inhibition of thromboxane synthase.

Adrenomedullin enhances therapeutic potency of bone marrow transplantation for myocardial infarction in rats.

Adrenomedullin (AM), a potent vasodilator, induces angiogenesis and inhibits cell apoptosis through the phosphatidylinositol 3-kinase/Akt pathway. Transplantation of bone marrow-derived mononuclear cells (MNC) induces angiogenesis. We investigated whether infusion of AM enhances the therapeutic potency of MNC transplantation in a rat model of myocardial infarction. Immediately after coronary ligation, bone marrow-derived MNC (5 x 10(6) cells) were injected into the ischemic myocardium, followed by subcutaneous administration of 0.05 microg x kg(-1) x min(-1) AM (AM-MNC group) or saline (MNC group) for 3 days. Another two groups of rats received subcutaneous administration of AM alone (AM group) or saline (control group). Hemodynamic and histological analyses were performed 4 wk after treatment. Cardiac infarct size was significantly smaller in the MNC and AM groups than in the control group. A combination of AM infusion and MNC transplantation demonstrated a further decrease in infarct size. Left ventricular (LV) maximum change in pressure over time and LV fractional shortening were significantly improved only in the AM-MNC group. AM significantly increased capillary density in ischemic myocardium, suggesting the angiogenic potency of AM. AM infusion plus MNC transplantation demonstrated a further increase in capillary density compared with AM or MNC alone. Although MNC apoptosis was frequently observed 72 h after transplantation, AM markedly decreased the number of terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling-positive cells among the transplanted MNC. In conclusion, AM enhanced the angiogenic potency of MNC transplantation and improved cardiac function in rats with myocardial infarction. This beneficial effect may be mediated partly by the angiogenic property of AM itself and by its antiapoptotic effect on MNC.

C-type natriuretic peptide attenuates bleomycin-induced pulmonary fibrosis in mice.

C-type natriuretic peptide (CNP) has been shown to play an important role in the regulation of vascular tone and remodeling. However, the physiological role of CNP in the lung remains unknown. Accordingly, we investigated whether CNP infusion attenuates bleomycin (BLM)-induced pulmonary fibrosis in mice. After intratracheal injection of BLM or saline, mice were randomized to receive continuous infusion of CNP or vehicle for 14 days. CNP infusion significantly reduced the total number of cells and the numbers of macrophages, neutrophils, and lymphocytes in bronchoalveolar lavage fluid. Interestingly, CNP markedly reduced bronchoalveolar lavage fluid IL-1beta levels. Immunohistochemical analysis demonstrated that CNP significantly inhibited infiltration of macrophages into the alveolar and interstitial regions. CNP infusion significantly attenuated BLM-induced pulmonary fibrosis, as indicated by significant decreases in Ashcroft score and lung hydroxyproline content. CNP markedly decreased the number of Ki-67-positive cells in fibrotic lesions of the lung, suggesting antiproliferative effects of CNP on pulmonary fibrosis. Kaplan-Meier survival curves demonstrated that BLM mice treated with CNP had a significantly higher survival rate than those given vehicle. These results suggest that continuous infusion of CNP attenuates BLM-induced pulmonary fibrosis and improves survival in BLM mice, at least in part by inhibition of pulmonary inflammation and cell proliferation.

A combination of oral sildenafil and beraprost ameliorates pulmonary hypertension in rats.

Sildenafil, an oral phosphodiesterase type-5 inhibitor, has vasodilatory effects through a cyclic guanosine 3', 5'-monophosphate-dependent mechanism, whereas beraprost, an oral prostacyclin analog, induces vasorelaxation through a cAMP-dependent mechanism. We investigated whether the combination of oral sildenafil and beraprost is superior to each drug alone in the treatment of pulmonary hypertension. Rats were randomized to receive repeated administration of saline, sildenafil, beraprost, or both of these drugs twice a day for 3 weeks. Three weeks after monocrotaline (MCT) injection, there was significant development of pulmonary hypertension. The increases in right ventricular systolic pressure and ratio of right ventricular weight to body weight were significantly attenuated in the Sildenafil and Beraprost groups. Combination therapy with sildenafil and beraprost had additive effects on increases in plasma cAMP and cyclic guanosine 3', 5'-monophosphate levels, resulting in further improvement in pulmonary hemodynamics compared with treatment with each drug alone. Unlike MCT rats given saline, sildenafil, or beraprost alone, all rats treated with both drugs remained alive during 6-week follow-up. These results suggest that combination therapy with oral sildenafil and beraprost attenuates the development of MCT-induced pulmonary hypertension compared with treatment with each drug alone.

Intravenous administration of mesenchymal stem cells improves cardiac function in rats with acute myocardial infarction through angiogenesis and myogenesis.

Mesenchymal stem cells (MSCs) are pluripotent cells that differentiate into a variety of cells, including cardiomyocytes and endothelial cells. However, little information is available regarding the therapeutic potency of systemically delivered MSCs for myocardial infarction. Accordingly, we investigated whether intravenously transplanted MSCs induce angiogenesis and myogenesis and improve cardiac function in rats with acute myocardial infarction. MSCs were isolated from bone marrow aspirates of isogenic adult rats and expanded ex vivo. At 3 h after coronary ligation, 5 x 10(6) MSCs (MSC group, n=12) or vehicle (control group, n=12) was intravenously administered to Lewis rats. Transplanted MSCs were preferentially attracted to the infarcted, but not the noninfarcted, myocardium. The engrafted MSCs were positive for cardiac markers: desmin, cardiac troponin T, and connexin43. On the other hand, some of the transplanted MSCs were positive for von Willebrand factor and formed vascular structures. Capillary density was markedly increased after MSC transplantation. Cardiac infarct size was significantly smaller in the MSC than in the control group (24 +/- 2 vs. 33 +/- 2%, P <0.05). MSC transplantation decreased left ventricular end-diastolic pressure and increased left ventricular maximum dP/dt (both P <0.05 vs. control). These results suggest that intravenous administration of MSCs improves cardiac function after acute myocardial infarction through enhancement of angiogenesis and myogenesis in the ischemic myocardium.

C-type natriuretic peptide ameliorates monocrotaline-induced pulmonary hypertension in rats.

C-type natriuretic peptide (CNP) has been shown to act as a local regulator of vascular tone and remodeling. We investigated whether CNP ameliorates monocrotaline (MCT)-induced pulmonary hypertension in rats. Rats received a continuous infusion of CNP or placebo. Significant pulmonary hypertension developed 3 weeks after MCT. However, infusion of CNP significantly attenuated the development of pulmonary hypertension and vascular remodeling. Neither systemic arterial pressure nor heart rate was altered. Interestingly, CNP enhanced Ki-67 expression, a marker for cell proliferation, in pulmonary endothelial cells and augmented lung tissue content of endothelial nitric oxide synthase. CNP significantly suppressed apoptosis of pulmonary endothelial cells, decreased the number of monocytes/macrophages, and inhibited expression of plasminogen activator inhibitor type 1, a marker for fibrinolysis impairment, in the lung. In addition, CNP significantly increased the survival rate in MCT rats. Finally, infusion of CNP after the establishment of pulmonary hypertension also had beneficial effects on hemodynamics and survival. In conclusion, infusion of CNP ameliorated MCT-induced pulmonary hypertension and improved survival. These beneficial effects may be mediated by regeneration of pulmonary endothelium, inhibition of endothelial cell apoptosis, and prevention of monocyte/macrophage infiltration and fibrinolysis impairment.

Elevated plasma ghrelin level in underweight patients with chronic obstructive pulmonary disease.

Ghrelin, a novel growth hormone-releasing peptide, has been shown to cause a positive energy balance by reducing fat use and stimulating food intake. This study investigated whether plasma ghrelin is associated with clinical parameters in patients with chronic obstructive pulmonary disease. Plasma ghrelin was measured in 50 patients and 13 control subjects, together with anabolic and catabolic factors. Patients were divided into two groups based on body mass index: underweight patients (n = 26) or normal weight patients (n = 24). Plasma ghrelin was significantly higher in underweight patients than in normal weight patients and healthy control subjects. Circulating tumor necrosis factor-alpha, interleukin-6, and norepinephrine were significantly higher in underweight patients than in normal weight patients. Plasma ghrelin correlated negatively with body mass index and correlated positively with catabolic factors such as tumor necrosis factor-alpha and norepinephrine. In addition, plasma ghrelin correlated positively with percent predicted residual volume and residual volume-to-total lung capacity ratio. In conclusion, plasma ghrelin was elevated in underweight patients with chronic obstructive pulmonary disease, and the level was associated with a cachectic state and abnormality of pulmonary function.