Drug therapy of primary pulmonary hypertension

Primary pulmonary hypertension (PPH) is a rare but life-threatening disease. Median survival, from the time of diagnosis, is considered to be 2.8 years. However, therapeutic medical advances over the past 2 decades have resulted in significant improvements in quality of life and survival in patients with PPH. Because pulmonary vasoconstriction, endothelial cell proliferation, smooth muscle cell proliferation, and in situ thrombosis contribute to the development of this disease, treatment with vasodilators, anti-proliferative agents, and anticoagulants is recommended.Currently, oral administration of calcium channel antagonists and intravenous infusion of epoprostenol (prostacyclin) are established as treatment of PPH. Epoprostenol has vasoprotective effects including vasodilation, anti-platelet aggregation, and inhibition of smooth muscle cell proliferation. Interestingly, prostacyclin synthase deficiency in the lungs, and impaired prostacyclin production, have been linked to the development of pulmonary hypertension in this disease. As a result, continuous intravenous infusion of epoprostenol has become recognized as a therapeutic breakthrough that can improve hemodynamics and survival in patients with PPH. The dramatic success of long-term intravenous prostacyclin is now leading to the development of epoprostenol analogs using newer drug delivery systems (oral beraprost, aerosolized iloprost, and subcutaneous treprostinil). In addition, promising drugs including endothelin antagonists and type V phosphodiesterase inhibitors have recently been developed. Furthermore, gene therapy with endothelial nitric oxide synthase gene or prostacyclin synthase gene may hold great promise in the treatment of PPH. Finally, accurate evaluation of disease severity and the efficacy of vasodilator therapy are important in the management of patients with PPH. In addition to invasive assessment by cardiac catheterization, we recommend repeated measurements of plasma brain natriuretic peptide, serum uric acid, and the distance walked in 6 minutes. These noninvasive parameters may be helpful as part of the evaluation of treatment in patients with PPH and, in particular, as a guide to the selection and timing for alternative therapies.

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.

Two molecular forms of adrenomedullin in congenital heart disease

To investigate the pathophysiological role of two forms of adrenomedullin (AM), a mature AM (AM-m) and a glycine-extended AM (AM-Gly), in congenital heart disease, we measured plasma levels of AM in patients with cyanotic heart disease, high pulmonary blood flow without pulmonary hypertension (PH), high pulmonary blood flow with PH, Fontan procedure, intracardiac repair without complication, and intracardiac repair with PH and control subjects. Plasma AM-m and AM-Gly were increased only for cyanotic heart disease (2.5 +/- 1.3 pmol/L, p < 0.001; 13.1 +/- 6.2 pmol/L, p < 0.05) and intracardiac repair with PH (2.3 +/- 1.5 pmol/L, p < 0.01; 13.0 +/- 7.0 pmol/L, p < 0.05) compared with control (1.0 +/- 1.4 and 8.6 +/- 1.3 pmol/L, respectively). They were similarly correlated with mean systemic arterial pressure (r = -0.40 and -0.37 respectively; p < 0.001), mixed venous oxygen saturation (r = -0.60 and -0.50; p < 0.0001), systemic arterial oxygen saturation (SA(sat)) (r = -0.56 and -0.46; p < 0.0001), and pulmonary arterial resistance (Rp) (r = 0.41 and 0.38; p < 0.005). Multiple regression analysis revealed that SA(sat) and Rp were independently correlated with AM. Interestingly, the venous AM-m level was significantly higher than the arterial AM-m, suggesting that the mature form is extracted in pulmonary circulation, whereas there were no venoarterial differences in AM-Gly. These results suggest that plasma AM-m and AM-Gly are similarly regulated and the main clearance site of AM-m is the lung in patients with congenital heart disease.

Repeated inhalation of adrenomedullin ameliorates pulmonary hypertension and survival in monocrotaline rats

Adrenomedullin (AM) is a potent vasodilator peptide. We investigated whether inhalation of aerosolized AM ameliorates monocrotaline (MCT)-induced pulmonary hypertension in rats. Male Wistar rats given MCT (MCT rats) were assigned to receive repeated inhalation of AM ( n = 8) or 0.9% saline ( n = 8). AM (5 μg/kg) or saline was inhaled as an aerosol using an ultrasonic nebulizer for 30 min four times a day. After 3 wk of inhalation therapy, mean pulmonary arterial pressure and total pulmonary resistance were markedly lower in rats treated with AM than in those given saline [mean pulmonary arterial pressure: 22 ± 2 vs. 35 ± 1 mmHg (–37%); total pulmonary resistance: 0.048 ± 0.004 vs. 0.104 ± 0.006 mmHg · ml–1 · min–1 · kg–1 (–54%), both P < 0.01]. Neither systemic arterial pressure nor heart rate was altered. Inhalation of AM significantly attenuated the increase in medial wall thickness of peripheral pulmonary arteries in MCT rats. Kaplan-Meier survival curves demonstrated that MCT rats treated with aerosolized AM had a significantly higher survival rate than those given saline (70% vs. 10% 6-wk survival, log-rank test, P < 0.01). In conclusion, repeated inhalation of AM inhibited MCT-induced pulmonary hypertension without systemic hypotension and thereby improved survival in MCT rats.

Increase in Thrombomodulin Concentrations After Pulmonary Thromboendarterectomy in Chronic Thromboembolic Pulmonary Hypertension

STUDY OBJECTIVES

The objectives of the study were as follows: (1) to identify differences in endothelial dysfunction and altered hemostasis in patients with chronic thromboembolic pulmonary hypertension (CTEPH) compared with patients with acute pulmonary thromboembolism (APTE) uncomplicated by pulmonary arterial hypertension, by measuring the concentrations of thrombomodulin (TM), a receptor for thrombin and a major anticoagulant proteoglycan on the endothelial membrane, and other plasma factors of coagulation and fibrinolysis; and (2) to examine the effects of thromboendarterectomy on TM levels as a parameter of endothelial cell injury leading to abnormal hemostasis as well as to examine the clinical significance of TM as a marker of endothelial injury.

DESIGN

Prospective comparison of concentrations of TM and other plasma parameters among patients with CTEPH or APTE and control subjects.

PARTICIPANTS

We studied 22 healthy subjects (ie, control subjects), 22 patients who had been clinically stabilized after APTE, and 44 patients with CTEPH. In 21 of the patients with CTEPH, measurements were repeated after they had undergone pulmonary thromboendarterectomy.

MEASUREMENTS AND RESULTS

Plasma concentrations of soluble TM in patients with CTEPH were measured and compared with those in patients with APTE. The mean (+/- SD) TM concentration in the CTEPH group (2.5 +/- 0.7 ng/mL) was significantly lower than that in the control group (4.0 +/- 0.6 ng/mL; p < 0.05). In contrast, the mean plasma TM concentration in the APTE group (4.6 +/- 1.9 ng/mL) was similar to that in the control group. After patients underwent pulmonary thromboendarterectomy, the mean TM concentration increased from 2.0 +/- 0.4 to 2.9 +/- 0.7 ng/mL (p < 0.05). In the CTEPH group, the plasma TM concentration was negatively correlated with mean pulmonary arterial pressure and total pulmonary resistance (p < 0.05).

CONCLUSIONS

A decreased plasma TM concentration may reflect pulmonary vascular endothelial dysfunction leading to altered anticoagulant and fibrinolytic function in CTEPH, which rarely develops after APTE. Plasma TM measurements may be useful in distinguishing CTEPH with severe pulmonary hypertension from recurrent APTE.

Ghrelin improves endothelial dysfunction through growth hormone-independent mechanisms in rats

Ghrelin is a novel growth hormone (GH)-releasing peptide which was isolated from the stomach. We have reported that ghrelin causes vasorelaxation in rats through GH-independent mechanisms. We investigated whether ghrelin improves endothelial dysfunction. Ghrelin was subcutaneously administered to GH-deficient rats for three weeks. After isolation of the thoracic aorta, aortic ring tension was measured to evaluate vasorelaxation. Acetylcholine-induced vasorelaxation was impaired in GH-deficient rats given placebo compared to that in normal rats given placebo. GH-deficient rats treated with ghrelin, however, showed a significant increase in the maximal relaxation as compared with those given placebo. This improvement by ghrelin was inhibited by N(G)-nitro-L-arginine methyl ester, a nonselective nitric oxide synthase (NOS) inhibitor. Western blot analysis demonstrated that treatment with ghrelin increased endothelial NOS (eNOS) expression in the aorta of GH-deficient rats. These results suggest that administration of ghrelin improves endothelial dysfunction and increases eNOS expression in rats through GH-independent mechanisms.

Cardiovascular and hormonal effects of subcutaneous administration of ghrelin, a novel growth hormone-releasing peptide, in healthy humans

Ghrelin is a novel GH (growth hormone)-releasing peptide isolated from the stomach. The cardiovascular and hormonal effects of the subcutaneous administration of ghrelin in humans remain unknown. Six healthy volunteers each received subcutaneous administration of three doses of ghrelin (1, 5 or 10 microg/kg) and placebo; the order of administration was randomized, and separate doses were given at least 24 h apart. The serum GH level dose-dependently increased from 0.5 +/- 0.4 to 3.6 +/- 2.1 ng/ml (1 microg/kg ghrelin; P=0.99 compared with baseline), 27.1 +/- 12.0 ng/ml (5 microg/kg; P<0.01 compared with baseline) and 45.4 +/- 12.8 ng/ml (10 microg/kg; P<0.01 compared with baseline) 30 min after ghrelin administration. Subcutaneous administration of ghrelin did not significantly alter circulating levels of corticotropin, cortisol, insulin-like growth factor-1, noradrenaline or adrenaline, although 10 microg/kg ghrelin slightly increased the prolactin level. No significant changes in heart rate or mean arterial pressure were observed. In contrast, the left ventricular ejection fraction, as assessed by echocardiography, increased dose-dependently from 63.5 +/- 0.6% to 65.1 +/- 0.9% (1 microg/kg ghrelin; P=0.97 compared with baseline), 69.6 +/- 1.3% (5 microg/kg; P<0.01 compared with baseline) and 71.5 +/- 0.9% (10 microg/kg; P<0.01 compared with baseline) 30 min after ghrelin administration. These haemodynamic and hormonal changes were still apparent 60 min after ghrelin injection. In conclusion, subcutaneous administration of ghrelin dose-dependently induced relatively specific GH release and enhanced cardiac performance in humans.

Hybrid cell-gene therapy for pulmonary hypertension based on phagocytosing action of endothelial progenitor cells

BACKGROUND

Circulating endothelial progenitor cells (EPCs) migrate to injured vascular endothelium and differentiate into mature endothelial cells. We investigated whether transplantation of vasodilator gene-transduced EPCs ameliorates monocrotaline (MCT)-induced pulmonary hypertension in rats.

METHODS AND RESULTS

We obtained EPCs from cultured human umbilical cord blood mononuclear cells and constructed plasmid DNA of adrenomedullin (AM), a potent vasodilator peptide. We used cationic gelatin to produce ionically linked DNA-gelatin complexes. Interestingly, EPCs phagocytosed plasmid DNA-gelatin complexes, which allowed nonviral, highly efficient gene transfer into EPCs. Intravenously administered EPCs were incorporated into the pulmonary vasculature of immunodeficient nude rats given MCT. Transplantation of EPCs alone modestly attenuated MCT-induced pulmonary hypertension (16% decrease in pulmonary vascular resistance). Furthermore, transplantation of AM DNA-transduced EPCs markedly ameliorated pulmonary hypertension in MCT rats (39% decrease in pulmonary vascular resistance). MCT rats transplanted with AM-expressing EPCs had a significantly higher survival rate than those given culture medium or EPCs alone.

CONCLUSIONS

Umbilical cord blood-derived EPCs had a phagocytosing action that allowed nonviral, highly efficient gene transfer into EPCs. Transplantation of AM gene-transduced EPCs caused significantly greater improvement in pulmonary hypertension in MCT rats than transplantation of EPCs alone. Thus, a novel hybrid cell-gene therapy based on the phagocytosing action of EPCs may be a new therapeutic strategy for the treatment of pulmonary hypertension.

Ghrelin, a novel growth hormone-releasing peptide, in the treatment of chronic heart failure

Ghrelin is a novel growth hormone (GH)-releasing peptide, isolated from the stomach, which has been identified as an endogenous ligand for growth-hormone secretagogues receptor (GHS-R). This peptide also causes a positive energy balance by stimulating food intake and inducing adiposity through growth hormone-independent mechanisms. In addition, ghrelin has some cardiovascular effects, as indicated by the presence of its receptor in blood vessels and the cardiac ventricles. In vitro, ghrelin inhibits apoptosis of cardiomyocytes and endothelial cells. In humans, infusion of ghrelin decreases systemic vascular resistance and increases cardiac output in patients with heart failure. Repeated administration of ghrelin improves cardiac structure and function and attenuates the development of cardiac cachexia in rats with heart failure. These results suggest that ghrelin has cardiovascular effects and regulates energy metabolism through GH-dependent and -independent mechanisms. Thus, administration of ghrelin may be a new therapeutic strategy for the treatment of severe chronic heart failure (CHF).

Changes in functional and histological distributions of nitric oxide synthase caused by chronic hypoxia in rat small pulmonary arteries

1. Chronic hypoxia (CH) increases lung tissue expression of all types of nitric oxide synthase (NOS) in the rat. However, it remains unknown whether CH-induced changes in functional and histological NOS distributions are correlated in rat small pulmonary arteries. 2. We measured the effects of NOS inhibitors on the internal diameters (ID) of muscular (MPA) and elastic (EPA) pulmonary arteries (100-700 micro m ID) using an X-ray television system on anaesthetized rats. We also conducted NOS immunohistochemical localization on the same vessels. 3. Nonselective NOS inhibitors induced ID reductions in almost all MPA of CH rats (mean reduction, 36+/-3%), as compared to approximately 60% of control rat MPA (mean, 10+/-2%). The inhibitors reduced the ID of almost all EPA with similar mean values (approximately 26%) in both CH and control rats. On the other hand, inducible NOS (iNOS)-selective inhibitors caused ID reductions in approximately 60% of CH rat MPA (mean, 15+/-3%), but did so in only approximately 20% of control rat MPA (mean, 2+/-2%). This inhibition caused only a small reduction (mean, approximately 4%) in both CH and control rat EPA. A neuronal NOS-selective inhibitor had no effect. 4. The percentage of endothelial NOS (eNOS)-positive vessels was approximately 96% in both MPA and EPA from CH rats, whereas it was 51 and 91% in control MPA and EPA, respectively. The percentage for iNOS was approximately 60% in both MPA and EPA from CH rats, but was only approximately 8% in both arteries from control rats. 5. The data indicate that in CH rats, both functional and histological upregulation of eNOS extensively occurs within MPA. iNOS protein increases sporadically among parallel-arranged branches in both MPA and EPA, but its vasodilatory effect is predominantly observed in MPA. Such NOS upregulation may serve to attenuate hypoxic vasoconstriction, which occurs primarily in MPA and inhibit the progress of pulmonary hypertension.

Hemodynamic and hormonal effects of beraprost sodium, an orally active prostacyclin analogue, in patients with secondary precapillary pulmonary hypertension

Earlier studies have shown that administration of beraprost sodium (BPS), an orally active prostacyclin analogue, improves hemodynamics in patients with primary pulmonary hypertension (PH), but it is not known whether BPS has beneficial effects in secondary precapillary PH. The present study investigated the hemodynamic and hormonal parameters of 18 patients with secondary precapillary PH (8 patients with chronic thromboembolic PH, 7 with collagen vascular disease, and 3 with residual PH after surgery for atrial septal defect). Hemodynamics were repeatedly measured by right heart catheterization. Treatment with BPS improved New York Heart Association (NYHA) functional class in 10 of the 18 patients and significantly decreased pulmonary vascular resistance by 17% (12.9+/-1.1 to 10.7+/-1.2 Wood units, p<0.01). Circulating brain natriuretic peptide and uric acid significantly decreased from 246+/-61 to 215+/-65 pg/ml and from 6.5+/-0.6 to 5.3+/-0.3 mg/dl, respectively. In summary, BPS therapy improved NYHA functional class, hemodynamics, and hormonal parameters in patients with secondary precapillary PH. Thus, oral administration of BPS may be a new therapeutic strategy for the treatment of secondary precapillary PH.

Effect of orally active prostacyclin analogue on survival in patients with chronic thromboembolic pulmonary hypertension without major vessel obstruction

OBJECTIVES

This study investigated whether treatment with beraprost sodium (BPS), an orally active prostacyclin analog, improves hemodynamics and survival in patients with peripheral-vessel chronic thromboembolic pulmonary hypertension (CTEPH), for which there is no surgical option.

BACKGROUND

Oral administration of BPS has been shown to improve the hemodynamics and prognosis in patients with primary pulmonary hypertension; however, whether BPS has beneficial effects in CTEPH remains unknown.

METHODS

Forty-three patients with peripheral-vessel CTEPH were classified into two groups: patients treated with BPS (BPS group, n = 20) and those without BPS (conventional group, n = 23). Baseline demographic and hemodynamic data did not significantly differ between the two groups.

RESULTS

BPS therapy improved New York Heart Association functional class in 10 patients (50%) and significantly decreased total pulmonary resistance from 18 +/- 6 to 15 +/- 8 Wood units (p < 0.05) [mean +/- SD]. Sixteen patients died of cardiopulmonary causes in the conventional group during a mean follow-up period of 58 +/- 45 months. In contrast, only three patients died of cardiopulmonary causes in the BPS group during a mean follow-up period of 44 +/- 30 months. The absence of BPS therapy, elevated total pulmonary resistance, heart rate, and age were independently related to the mortality by Cox proportional hazard analysis. The 1-year, 3-year, and 5-year survival rates for the BPS group were 100%, 85%, and 76%, respectively, compared to 87%, 60%, and 46% in the conventional group.

CONCLUSIONS

This preliminary study suggests that oral administration of BPS may improve hemodynamics and survival in patients with peripheral-vessel CTEPH, for which there is no surgical option.

Ghrelin improves left ventricular dysfunction and cardiac cachexia in heart failure

Ghrelin is a novel growth-hormone-releasing peptide isolated from the stomach that has been identified as an endogenous ligand for the growth-hormone secretagogue receptor. This peptide results in a positive energy balance by stimulating food intake and inducing adiposity through growth-hormone-independent mechanisms. In addition, ghrelin has several cardiovascular effects, as indicated by the presence of its receptor in blood vessels and ventricles of the heart. Infusion of ghrelin decreases systemic vascular resistance and increases cardiac output in patients with heart failure. Furthermore, repeated administration of ghrelin improves cardiac structure and function, and attenuates the development of cardiac cachexia in rats with heart failure. These results suggest that ghrelin has therapeutic potential in the treatment of severe chronic heart failure.

Myocardial velocity gradient reflects the severity of myocardial damage regardless of the presence or absence of mitral regurgitation

Complicating mitral regurgitation (MR) apparently enhances left ventricular ejection fraction, thereby leading to the underestimation of myocardial damage by routine echocardiography. We sought to assess the significance of myocardial velocity gradient (MVG) derived from Doppler tissue imaging as an indicator of the severity of myocardial damage in the presence or absence of MR. Peak systolic and diastolic MVG was obtained from 39 participants: 12 healthy participants, 10 patients with dilated cardiomyopathy complicating moderate to severe MR [MR (+) group], and 17 patients with dilated cardiomyopathy without significant MR [MR (-) group]. MVG was compared with standard echocardiographic and Doppler transmitral flow velocity indices. Plasma brain natriuretic peptide levels were measured in all patients. Left ventricular dimension and fractional shortening was similar between MR (+) and MR (-) groups. Plasma brain natriuretic peptide levels were significantly increased in MR (+) group (440 +/- 417 pg/mL) as compared with MR (-) group (122 +/- 107 pg/mL, P <.05). Peak systolic MVG was significantly attenuated in dilated cardiomyopathy group with or without MR [MR (+) group = 1.3 +/- 0.5 seconds(-1), MR (-) group = 2.1 +/- 0.5 seconds(-1), where normal = 4.0 +/- 0.9 seconds(-1), P <.01, respectively]. Peak systolic MVG was further attenuated in MR (+) group than in MR (-) group (P <.01). Plasma brain natriuretic peptide levels were negatively correlated with peak systolic MVG (r = -0.66, P <.0005). Peak diastolic MVG was attenuated in MR (+) and also in MR (-) groups [MR (+) group = -4.5 +/- 2.0 seconds(-1), MR (-) group = -4.4 +/- 1.1 seconds(-1), where normal = -8.7 +/- 2.4 seconds(-1), P <.01, respectively], whereas transmitral flow indices failed to distinguish MR (+) group from normal as a result of pseudonormalization. MVG may reflect the severity of myocardial damage regardless of the presence or absence of complicating MR.

Epinephrine unmasks latent mutation carriers with LQT1 form of congenital long-QT syndrome

OBJECTIVES

This study was designed to test the hypothesis that epinephrine infusion may be a provocative test able to unmask nonpenetrant KCNQ1 mutation carriers.

BACKGROUND

The LQT1 form of congenital long QT syndrome is associated with high vulnerability to sympathetic stimulation and appears with incomplete penetrance.

METHODS

The 12-lead electrocardiographic parameters before and after epinephrine infusion were compared among 19 mutation carriers with a baseline corrected QT interval (QTc) of > or =460 ms (Group I), 15 mutation carriers with a QTc of <460 ms (Group II), 12 nonmutation carriers (Group III), and 15 controls (Group IV).

RESULTS

The mean corrected Q-Tend (QTce), Q-Tpeak (QTcp), and Tpeak-end (Tcp-e) intervals among 12-leads before epinephrine were significantly larger in Group I than in the other three groups. Epinephrine (0.1 microg/kg/min) increased significantly the mean QTce, QTcp, Tcp-e, and the dispersion of QTcp in Groups I and II, but not in Groups III and IV. The sensitivity and specificity of QTce measurements to identify mutation carriers were 59% (20/34) and 100% (27/27), respectively, before epinephrine, and the sensitivity was substantially improved to 91% (31/34) without the expense of specificity (100%, 27/27) after epinephrine. The mean QTce, QTcp, and Tcp-e before and after epinephrine were significantly larger in 15 symptomatic than in 19 asymptomatic mutation carriers in Groups I and II, and the prolongation of the mean QTce with epinephrine was significantly larger in symptomatic patients.

CONCLUSIONS

Epinephrine challenge is a powerful test to establish electrocardiographic diagnosis in silent LQT1 mutation carriers, thus allowing implementation of prophylactic measures aimed at reducing sudden cardiac death.

Prostacyclin therapy before pulmonary thromboendarterectomy in patients with chronic thromboembolic pulmonary hypertension

OBJECTIVES

The continuous IV administration of prostacyclin improves pulmonary hemodynamics and prognosis in patients with primary pulmonary hypertension. We investigated whether the administration of prostacyclin therapy to patients before they undergo pulmonary thromboendarterectomy ameliorates pulmonary hypertension in patients with the most severe form of chronic thromboembolic pulmonary hypertension (CTEPH).

METHODS

Of the 33 patients with CTEPH who were candidates for pulmonary thromboendarterectomy, 12 patients with severe pulmonary hypertension (pulmonary vascular resistance, > 1,200 dyne. s. cm(-5)) received IV prostacyclin prior to undergoing pulmonary thromboendarterectomy. Right heart catheterization and plasma brain natriuretic peptide (BNP) measurements were repeated at baseline, immediately before surgery, and 1 month after surgery.

RESULTS

During a mean (+/- SEM) follow-up period of 46 +/- 12 days, the IV administration of prostacyclin resulted in a 28% decrease in pulmonary vascular resistance (1,510 +/- 53 to 1,088 +/- 58 dyne. s. cm(-5); p < 0.001) before surgery. Prostacyclin therapy markedly decreased plasma BNP level (547 +/- 112 to 188 +/- 30 pg/mL; p < 0.01), suggesting improvement in right heart failure. Pulmonary thromboendarterectomy caused a further reduction of pulmonary vascular resistance (302 +/- 47 dyne. s. cm(-5)) and plasma BNP levels (60 +/- 11 pg/mL) compared to each preoperative value (p < 0.05). Operative mortality rates were relatively low (8.3%) in patients with the most severe form of CTEPH.

CONCLUSION

The IV administration of prostacyclin caused beneficial hemodynamic effects in patients with severe CTEPH and may serve as pretreatment for patients undergoing pulmonary thromboendarterectomy.

Increased plasma ghrelin level in lung cancer cachexia

PURPOSE

Ghrelin, a novel growth hormone-releasing peptide,has been shown to cause a positive energy balance by stimulating food intake and inducing adiposity. We sought to investigate the pathophysiology of ghrelin in cachexia associated with lung cancer.

EXPERIMENTAL DESIGN

Plasma ghrelin level was measured in 43 patients with lung cancer and 21 control subjects. Patients with lung cancer were divided into two groups: patients with cachexia (n = 21) and those without cachexia (n = 22).

RESULTS

Plasma ghrelin level did not significantly differ between all patients with lung cancer and controls (157 +/- 10 versus 132 +/- 8 fmol/ml, P = 0.1). However, plasma ghrelin level was significantly higher in patients with cachexia than in those without cachexia (180 +/- 17 versus 135 +/- 10 fmol/ml, P = 0.011). Furthermore, plasma ghrelin level increased significantly in patients with decreased food intake after chemotherapy (from 136 +/- 11 fmol/ml to 170 +/- 16 fmol/ml on day 8, 179 +/- 20 fmol/ml on day 21 after start of chemotherapy), although plasma ghrelin level did not significantly change in those without decreased food intake.

CONCLUSIONS

Baseline plasma ghrelin level was elevated in cachectic patients with lung cancer, and follow-up plasma ghrelin level increased in patients with anorexia after chemotherapy. Considering the positive energy effects induced by ghrelin, increased ghrelin may represent a compensatory mechanism under catabolic-anabolic imbalance in cachectic patients with lung cancer.

Adrenomedullin infusion during ischemia/reperfusion attenuates left ventricular remodeling and myocardial fibrosis in rats

Recent studies have demonstrated that the activation of protein kinase Akt attenuates myocardial ischemia/reperfusion injury. However, it remains unknown whether adrenomedullin (AM), which is also a potent Akt activator, has cardioprotective effects after ischemia/reperfusion. In the present study, Sprague-Dawley rats were exposed to a 30-min period of ischemia induced by ligation of the left coronary artery followed by 24-h reperfusion. They were randomized to receive intravenous administration of AM (0.05 microg/kg/min) or saline for 60 min after coronary ligation. We examined the hemodynamics and myocardial apoptosis 24 h after ischemia/reperfusion. Echocardiographic measurements were performed 4 weeks after ischemia/reperfusion. Myocardial infarct size was also measured histologically. AM significantly reduced left ventricular (LV) end-diastolic pressure (17 +/- 2 to 8 +/- 2 mmHg, p < 0.05) and the number of apoptotic nuclei in myocytes (387 +/- 39 to 147 +/- 72 per field, p < 0.05). AM significantly increased LV dP/dt(max) (4,803 +/- 228 to 5,672 +/- 199 mmHg/s, p < 0.05). AM significantly increased LV fractional shortening (23 +/- 2 vs. 28 +/- 2%, p < 0.05), and significantly reduced LV diastolic dimension (7.4 +/- 0.1 to 6.9 +/- 0.1 mm, p < 0.05) and myocardial infarct size (33 +/- 2 to 20 +/- 2%, p < 0.01) 4 weeks after ischemia/reperfusion. In conclusion, AM infusion during ischemia/reperfusion attenuated the development of LV remodeling and myocardial fibrosis in rats. Based on these results, the cardioprotective effects of AM may be attributed at least partly to its anti-apoptotic effect.

Pulmonary vasodilator response to adrenomedullin in patients with pulmonary hypertension

This study sought to investigate pulmonary vasodilator responses to intrapulmonary and intravenous infusion of adrenomedullin (AM) in patients with pulmonary hypertension. In 10 patients with pulmonary hypertension, blood flow velocity in a segmental pulmonary artery was measured using a Doppler flow wire during intrapulmonary infusion of AM, acetylcholine (ACh), and adenosine triphosphate (ATP). The hemodynamic effects of intravenously administered AM (0.05 microg/kg/min) were examined in another 5 patients with primary pulmonary hypertension. Intrapulmonary infusion of AM, ACh or ATP caused a significant dose-dependent increase in blood flow velocity in a segmental pulmonary artery, respectively. The increase in flow velocity with AM at 10(-8) mol/l (41 +/- 6% of the baseline value) was comparable to that with ACh at 10(-4) mol/l (39 +/- 11%) and that with ATP at 10(-5) mol/l (36 +/- 14%), suggesting a strong pulmonary vasodilator activity of AM. Intravenous infusion of AM produced a 41% increase in cardiac index (p < 0.05) and a 30% decrease in pulmonary vascular resistance (p < 0.05) with a 3% reduction in mean pulmonary arterial pressure (p = NS). These results suggest that, on a molar basis, AM may have much more potent pulmonary vasodilator activity than ACh and ATP, and thus may have beneficial hemodynamic effects in patients with pulmonary hypertension.

Lesion Severity and Hypercholesterolemia Determine Long-Term Prognosis of Vasospastic Angina Treated With Calcium Channel Antagonists

Although patients with medically treated vasospastic angina have a good outcome, few data exist regarding the role of underlying lesion severity associated with or without hyperlipidemia in the prognosis. Therefore, the aim of the present study was to assess the relationship between the long-term outcome of vasospastic angina and the factors influencing its prognosis. A total of 256 patients (219 men, 37 women; mean age, 54.1+/-9.2) who had coronary spasm with or without underlying lesions and were being treated with calcium channel antagonists were enrolled and followed for 13.6+/-3.7 years. Cardiac events consisted of cardiac death and ischemic events, which included acute myocardial infarction and unstable angina. Cox analysis selected coronary artery stenosis (CAS, >/=50%) and risk factors such as age, hypertension, diabetes mellitus, low-density lipoprotein-cholesterol (LDL-C), sex and smoking. There were 19 cases of cardiac death (7.4%) and 58 of ischemic events (22.7%) during the follow-up period. The presence of significant CAS was an independent predictor of event-free survival (hazard ratio (HR) =2.84, 95% confidence interval (CI) =1.79-4.52, p<0.0001). In 193 patients without significant CAS, there were 10 cases of cardiac death (5.2%, p<0.05) and 34 of ischemic events (17.6%, p<0.01). In that group, high LDL-C was the independent predictor of event-free survival (HR = 3.89, 95% CI = 1.20-12.6, p=0.02). Kaplan-Meier survival analysis revealed significantly lower event-free survival in patients with than in those without lesions (p<0.0001 by log-rank test). These results demonstrate that the most important factor for long-term prognosis of vasospastic angina treated with calcium channel antagonists is significant CAS. High LDL-C, which might alter the underlying coronary endothelial function and/or accelerate atherosclerotic lesions, could also contribute to the occurrence of cardiac events, particularly in patients without significant CAS.

Effect of disease eccentricity on compensatory remodeling of coronary arteries: evidence from intravascular ultrasound before interventions

BACKGROUND

Compensatory remodeling occurs to maintain lumen area in human coronary vessels. However, few data exist regarding the relationship between vessel remodeling and plaque distribution. Therefore, we studied coronary sites with or without remodeling by intravascular ultrasound and correlated with disease distribution.

METHODS AND RESULTS

A total of 90 coronary sites with significant stenosis (>50%) from 80 patients were examined before interventions. For identifying the vessel remodeling, external elastic membrane (EEM) area was measured at the stenotic sites and the adjacent proximal and distal sites. The reference EEM area was calculated by averaging proximal and distal EEM areas, and percent enlargement of the EEM area was calculated by the formula: [(stenosis EEM area-reference EEM area)/reference EEM area]x100. Plaque area was determined by reducing the lumen from EEM areas. The maximal (max) and minimal (min) distances from the center of the lumen to the EEM were also measured, and the disease eccentricity index was calculated by the formula: [(max-min)/max]. The lesion was defined as eccentric if the index was >0.5 and as concentric if <or=0.5. There were 39 eccentric and 51 concentric lesions. The enlargement remodeling was observed at 32 lesions with the enlargement of EEM area of 28.0+/-16.0% (5.5 to 71.3%). Enlargement was more frequently observed in the eccentric than in concentric lesions (P<0.05). However, within 32 stenoses, which showed enlargement, there was no difference in enlargement between eccentric (n=19, 25.6+/-21.0%) and concentric lesions (n=13, 21.5+/-12.0%). Also, there was no statistical correlation between the increase in plaque area and % enlargement of EEM area irrespective of plaque morphology.

CONCLUSIONS

These data demonstrate that in advanced coronary disease compensatory enlargement occurs more frequently at the eccentric than concentric coronary lesions. However, the EEM area was limited to expand regardless of the disease morphology.

Combined procedure of surgical repair and cell transplantation for left ventricular aneurysm: an experimental study

BACKGROUND

This study was designed to investigate the efficacy of the combined procedure of left ventricular (LV) repair and fetal cardiomyocyte transplantation (CM-TX) in a rat myocardial infarction model.

METHODS AND RESULTS

A moderate-sized LV aneurysm was created by proximal ligation of the left coronary artery in 47 Lewis rats. Four weeks later, they were underwent another operation and received culture medium injection (n=10; group I), fetal CM-TX (n=10; group II), purse-string LV repair with culture medium injection (n=14; group III), or LV repair with fetal CM-TX (n=13; group IV). They were echocardiographically followed-up during the subsequent 4 weeks, and cardiac catheterization was performed in the final week. In the late period, LV dimension in group IV was smaller than that in group III (end-diastolic dimension, 0.92+/-0.02 versus 1.01+/-0.03 cm, P=0.0090; end-systolic dimension, 0.62+/-0.02 versus 0.74+/-0.04 cm, P=0.0093; at the fourth week), although they initially showed similar decreases in both groups. At the final week, end-systolic elastance was higher in group IV than in groups I, II, or III (0.61+/-0.10 versus 0.19+/-0.03, 0.30+/-0.09, 0.33+/-0.07 mm Hg/ micro L, P=0.0002, 0.0037, and 0.0042, respectively).

CONCLUSIONS

Fetal CM-TX exerted preventive effects against late LV dilation and dysfunction after LV repair in the rat model. The results suggest that repair surgery combined with fetal CM-TX may enhance the surgical benefits for patients with LV aneurysm in the long term.

Effects of continuous IV prostacyclin in a patient with pulmonary veno-occlusive disease

Pulmonary veno-occlusive disease (PVOD) is a rare but life-threatening disease. Although prostacyclin (PGI(2)) attenuates pulmonary hypertension and improves the prognosis in patients with primary pulmonary hypertension, little information is available regarding the effect of PGI(2) on patients with PVOD. This report describes a patient with severe PVOD who showed marked improvement in exercise capacity and pulmonary hemodynamics with continuous IV PGI(2) treatment. Furthermore, he experienced no clinical events for 12 months and survived for 25 months after the initiation of PGI(2) therapy. These results suggest that continuous IV PGI(2) therapy may serve as a bridge to transplantation in some cases of PVOD.