Katsumasa Miyaji

Carvedilol decreases elevated oxidative stress in human failing myocardium

Background—Oxidative stress has been implicated in the pathogenesis of heart failure. However, direct evidence of oxidative stress generation in the human failing myocardium has not been obtained. Furthermore, the effect of carvedilol, a vasodilating &bgr;-blocker with antioxidant activity, on oxidative stress in human failing hearts has not been assessed. This study was therefore designed to determine whether levels of lipid peroxides are elevated in myocardia of patients with dilated cardiomyopathy (DCM) and whether carvedilol reduces the lipid peroxidation level. Methods and Results—Endomyocardial biopsy samples obtained from 23 patients with DCM and 13 control subjects with normal cardiac function were studied immunohistochemically for the expression of 4-hydroxy-2-nonenal (HNE)-modified protein, which is a major lipid peroxidation product. Expression of HNE-modified protein was found in all myocardial biopsy samples from patients with DCM. Expression was distinct in the cytosol of cardiac myocytes. Myocardial HNE-modified protein levels in patients with DCM were significantly increased compared with the levels in control subjects (P <0.0001). Endomyocardial biopsy samples from 11 patients with DCM were examined before and after treatment (mean, 9±4 months) with carvedilol (5 to 30 mg/d; mean dosage, 22±8 mg/d). After treatment with carvedilol, myocardial HNE-modified protein levels decreased by 40% (P <0.005) along with amelioration of heart failure. Conclusions—Oxidative stress is elevated in myocardia of patients with heart failure. Administration of carvedilol resulted in a decrease in the oxidative stress level together with amelioration of cardiac function.

Prednisolone Inhibits Proliferation of Cultured Pulmonary Artery Smooth Muscle Cells of Patients With Idiopathic Pulmonary Arterial Hypertension

Background—Idiopathic pulmonary arterial hypertension (IPAH) is associated with proliferation of smooth muscle cells (SMCs) in small pulmonary arteries. There is no therapy that specifically inhibits SMC proliferation. Recent studies reported that prednisolone (PSL) inhibits the postangioplasty proliferation of SMCs in atherosclerotic arteries. In this study, we tested the hypothesis that PSL has antiproliferative effects on pulmonary artery SMCs of patients with IPAH. Methods and Results—Pulmonary artery SMCs were harvested from the pulmonary arteries of 6 patients with IPAH who underwent lung transplantation. Control SMCs were obtained from 5 patients with bronchogenic carcinoma who underwent lung lobectomy. After incubation in the presence of platelet-derived growth factor (PDGF), PSL was added at different concentrations and cell proliferation was assessed by 3H-thymidine incorporation. PSL (2×10−4 and 2×10−3 mol/L) significantly inhibited PDGF-stimulated proliferation (P<0.05) of SMCs from patients with IPAH but did not affect cell viability of SMCs, as confirmed by trypan blue staining. In cell cycle analysis using a microscope-based multiparameter laser scanning cytometer, PSL inhibited the progression of SMCs from G0/G1 to the S phase. This inhibition was associated with increased p27 expression level. PSL (2×10−4 mol/L) also inhibited PDGF-induced SMC migration. Conclusions—Our results indicate that PSL has an antiproliferative effect on cultured SMCs of pulmonary arteries from patients with IPAH and suggest that PSL may be potentially useful therapeutically in patients with IPAH.

Novel Angiographic Classification of Each Vascular Lesion in Chronic Thromboembolic Pulmonary Hypertension Based on Selective Angiogram and Results of Balloon Pulmonary Angioplasty

Background—Balloon pulmonary angioplasty (BPA) is an alternative therapy for patients with chronic thromboembolic pulmonary hypertension who are ineligible for standard therapy, pulmonary endarterectomy. Although there are several classifications of vascular lesions, these classifications are based on the features of the specimen removed during pulmonary endarterectomy. Because organized thrombi are not removed during balloon pulmonary angioplasty, we attempted to establish a new classification of vascular lesions based on pulmonary angiographic images. We evaluated the success and complication rate of BPA in accordance with the location and morphology of thromboembolic lesions. Methods and Results—We reviewed 500 consecutive procedures (1936 lesions) of BPA in 97 patients with chronic thromboembolic pulmonary hypertension and investigated the outcomes of BPA based on the lesion distribution and the angiographic characteristics of the thromboembolic lesions, as follows: type A, ring-like stenosis lesion; type B, web lesion; type C, subtotal lesion; type D, total occlusion lesion, and type E, tortuous lesion. The success rate was higher, and the complication rate was lower in ring-like stenosis and web lesions. The total occlusion lesions had the lowest success rate. Tortuous lesions were associated with a high complication rate and should be treated only by operators with extensive experience with BPA. Conclusions—We modified the previous angiographic classification and established a new classification for each vascular lesion. We clarified that the outcome and complication rate of the BPA are highly dependent on the lesion characteristics.

Carvedilol inhibits proliferation of cultured pulmonary artery smooth muscle cells of patients with idiopathic pulmonary arterial hypertension.

Idiopathic pulmonary arterial hypertension (IPAH) is associated with proliferation of smooth muscle cells (SMCs) in small pulmonary arteries. Inhibition of proliferation of pulmonary artery smooth muscle cells (PASMCs) may be an effective treatment of patients with idiopathic pulmonary arterial hypertension. Recent studies have shown that carvedilol, an α- and β-blocker with antioxidant and calcium channel blocking properties, inhibits the proliferation of cultured normal human pulmonary artery smooth muscle cells. In this study, we tested the hypothesis that carvedilol has antiproliferative effects on pulmonary artery smooth muscle cells of patients with idiopathic pulmonary arterial hypertension. Pulmonary artery smooth muscle cells from six idiopathic pulmonary arterial hypertension patients who had undergone lung transplantation were cultured. To determine cell proliferation, 3H-thymidine incorporation was measured. Platelet-derived growth factor-induced proliferation of IPAH-PASMCs was significantly greater than that of normal control pulmonary artery smooth muscle cells. Carvedilol (0.1 μM to 10 μM) inhibited the proliferation of idiopathic pulmonary arterial hypertension-pulmonary artery smooth muscle cells in a concentration-dependent manner. Prazosin (an α-blocker) and N-acetyl L cysteine (an antioxidant agent) (0.1 μM to 10 μM) did not inhibit their proliferation, but the high concentration of propranolol (a β-blocker) and nifedipine (a calcium channel blocker) (10 μM) inhibited the proliferation. The combination of propranolol and nifedipine inhibited the proliferation but only at a high concentration (10 μM) combination. Cell cycle analysis revealed that carvedilol (10 μM) significantly decreased the number of cells in S and G2/M phases. These results indicate that carvedilol inhibits the exaggerated proliferation of pulmonary artery smooth muscle cells of patients with idiopathic pulmonary arterial hypertension partially via its α-blocking and calcium channel blocking effects in vitro.

Prostaglandin I2 induces apoptosis via upregulation of Fas ligand in pulmonary artery smooth muscle cells from patients with idiopathic pulmonary arterial hypertension.

BACKGROUND Pulmonary vascular remodeling with idiopathic pulmonary arterial hypertension (IPAH) is associated with impaired apoptosis of pulmonary artery smooth muscle cells (PASMCs). We have reported that high-dose prostaglandin I2 (PGI2) therapy markedly improved hemodynamics in IPAH patients. The therapy is thought to reverse vascular remodeling, though the mechanism is unclear. The aim of this study is to assess proapoptotic effects of PGI2 on PASMCs obtained from IPAH patients. METHODS We investigated proapoptotic effects of PGI2 in PAH-PASMCs by TUNEL assays, caspase-3,-7 assays and transmission electron microscopy. We examined the expression of Fas ligand (FasL), an apoptosis-inducing member of the TNF cytokine family, in PAH-PASMCs. We measured the serum FasL levels in IPAH patients treated with PGI2. RESULTS TUNEL-positive, caspase-3, 7-active cells and fragmentation of the nucleus were detected in PAH-PASMCs treated with PGI2. The percentage of apoptotic cells induced by PGI2 at a high concentration was higher than that induced by PGI2 at a low concentration. PCR-array analysis revealed that PGI2 upregulated the FasL gene in PAH-PASMCs, and we measured the FasL expression by quantitative RT-PCR and Western blotting. PGI2 significantly increased the mRNA level of FasL by 3.98 fold and the protein level of FasL by 1.70 fold. An IP receptor antagonist inhibited the induction of apoptosis, elevation of cyclic AMP and upregulation of FasL by PGI2. Serum FasL level had a significant positive correlation with PGI2 dose in IPAH patients treated with PGI2. CONCLUSIONS PGI2 has proapoptotic effects on PAH-PASMCs via the IP receptor and upregulation of FasL.

Total Ca handling in canine mild Ca overload failing heart

SummaryWe analyzed total Ca handling of the left ventricle (LV) in the mildly failing heart preparation induced by a temporary intracoronary Ca overloading intervention in eight excised and cross-circulated canine hearts. This Ca intervention consisted of interruption of coronary blood perfusion by Ca-free oxygenated Tyrode perfusion for 10min followed by high-Ca (16 mmol/l) oxygenated Tyrode perfusion for 5 min. This intervention decreased the LV contractility index,Emax (end-systolic maximum elastance), by 40% after restoration of the blood cross-circulation. We expected a Ca overload or paradox failing heart resembling the postischemic stunned heart and being characterized by an increased O2 cost ofEmax. However, LV O2 consumption under mechanically unloading conditions decreased by 30% from control without increasing the O2 cost ofEmax. To obtain a mechanistic view of this failing heart, we investigated cardiac total Ca handling by our integrative analysis method. In this method, we obtained the internal Ca recirculation fraction (RF) from the decay beat constant of the postextrasystolic potentiation following each sporadic spontaneous extrasystole in these failing LVs. We combined the RF with the decreasedEmax and the unchanged O2 cost ofEmax in our recently developed formula of total Ca handling. We found that these failing LVs had a slightly but significantly increased RF accompanied by either a slightly increased futile Ca cycling or a slightly decreased Ca reactivity ofEmax, or both. Any of these three possible changes can account for the unchanged O2 cost ofEmax. This result indicates that the present mildly failing heart has not yet fallen into a typical Ca overload or paradox by the temporary Ca overloading intervention.

Catecholamine Support at the Initiation of Epoprostenol Therapy in Pulmonary Arterial Hypertension

RATIONALE Epoprostenol is a first-line therapy for patients with pulmonary arterial hypertension (PAH) in World Health Organization functional class IV who often have low cardiac output and hypotension. However, initiation of epoprostenol can cause hemodynamic collapse in these vulnerable patients. Inotropic agent support may prevent the hemodynamic instability caused by initiation of epoprostenol; however, a protocol for supportive therapy has not been established. OBJECTIVES To assess the reliability and prognostic effects of dobutamine and dopamine support at the initiation of epoprostenol therapy in patients with PAH. METHODS We initiated epoprostenol therapy in 71 patients with PAH. Hemodynamics at the initiation of epoprostenol were measured by right heart catheterization. We initiated dobutamine when a patients mixed venous oxygen saturation was less than 60% or cardiac index was less than 2.0 L/min/m(2) or when right ventricular failure was clinically suspected. We initiated dopamine when a patients systolic blood pressure was less than 90 mm Hg or urine volume was less than 20 ml/h. MEASUREMENTS AND MAIN RESULTS At the initiation of epoprostenol, dobutamine and/or dopamine were required to support 46 patients according to protocol. Eight patients died during the hospitalization and one patient received a living-donor lobar lung transplant after the initiation of epoprostenol therapy. Neither inotropic agent was an independent risk factor for short-term mortality (dobutamine: hazard ratio, 1.63; 95% confidence interval, 0.33-8.11; dopamine: hazard ratio, 0.22; 95% confidence interval, 0.03-1.70). Sixty-two patients were discharged for home infusion of epoprostenol. Transplant-free survival rates at 5 years were 80.0% for patients who did not require inotropic support at the start of epoprostenol and 76.6% for patients with who did require dopamine and/or dobutamine support (P = 0.45). CONCLUSIONS Temporary use of dobutamine and dopamine appears to be safe for hemodynamic support at the initiation of epoprostenol therapy for selected patients with PAH with low cardiac output and hypotension. The protocol presented here requires validation at other centers.

Reverse remodeling of pulmonary arteries by high-dose prostaglandin I2 therapy: A case report

Idiopathic pulmonary arterial hypertension (IPAH) is characterized by pulmonary vascular remodeling. We have reported that high-dose prostaglandin I2 (PGI2) therapy markedly improved hemodynamics in IPAH patients and that PGI2 induced apoptosis of pulmonary artery smooth muscle cells obtained from IPAH patients. PGI2 is thought to have reverse remodeling effects, although it has not been histologically confirmed. In a case series, we examined the reverse pulmonary vascular remodeling effects of PGI2 in lung tissues obtained from an IPAH patient treated with high-dose PGI2 and an IPAH patient not treated with PGI2. Apoptotic cells were detected in small pulmonary arteries of the IPAH patient treated with high-dose PGI2 but not in those from the IPAH patient not treated with PGI2. Media of peripheral pulmonary arteries were thick in the IPAH patient not treated with PGI2. On the other hand, media of peripheral pulmonary arteries were thin in the IPAH patient treated with high-dose PGI2. The single case report suggested that high-dose PGI2 therapy has the potential for reverse pulmonary vascular remodeling by induction of apoptosis and reduction of medial hypertrophy. Accumulation of cases is needed for the application to generalized effect of high-dose PGI2. <Learning objective: Reverse pulmonary vascular remodeling would provide further improvement in patients with IPAH. High-dose PGI2 therapy has the potential for reverse pulmonary vascular remodeling in patients with IPAH.>.

Current trends in the management of pulmonary hypertension associated with respiratory disease in institutions approved by the Japanese Respiratory Society

BACKGROUND Pulmonary hypertension (PH) often correlates with respiratory disease severity. Right heart catheterization (RHC) is recommended for the definitive diagnosis of PH associated with respiratory disease (R-PH). However, no previous studies have evaluated the perceived necessity for pulmonologists to use RHC for R-PH diagnosis, or the management of R-PH in Japan. METHODS Questionnaires were mailed to 855 institutions, approved by the Japanese Respiratory Society. Questions included the prevalence and necessity of RHC and other methods in R-PH diagnosis, and current trends in the treatment of R-PH. RESULTS Questionnaires were returned from 289 institutions (34%). Patients with R-PH were examined by pulmonologists in 89% of institutions; some pulmonologists performed echocardiography (15%) and some RHC (13%). Echocardiography was used to diagnose R-PH in 99% of institutions and RHC was used in 36%. RHC was considered in cases of suspected PH in 49% of institutions and prior to initiation of pulmonary arterial hypertension (PAH)-specific therapy in 57%. Of patients diagnosed with R-PH, 47% were treated with ambulatory oxygen therapy. Furthermore, 98 of 145 institutions used PAH-specific therapy to treat R-PH. Of the 1355 patients who underwent RHC as a part of PH evaluation, 29% were confirmed to have PH, and 8% had severe PH with a mean pulmonary arterial pressure of ≥35mmHg. CONCLUSIONS The current diagnostic and treatment modalities for R-PH in Japan were evaluated. Although few pulmonologists perform RHC for R-PH diagnosis in Japan, more than half consider using RHC for patients before initiating PAH-specific therapy.

Response by Kawakami et al to Letter Regarding Article, “Novel Angiographic Classification of Each Vascular Lesion in Chronic Thromboembolic Pulmonary Hypertension Based on Selective Angiogram and Results of Balloon Pulmonary Angioplasty”

We thank Dr Roik et al for their interest in our study regarding novel angiographic classification of chronic thromboembolic pulmonary hypertension lesions.1 They raise the issue about the usage of pressure wire, intravascular ultrasound, and optical coherence tomography in performing balloon pulmonary angioplasty (BPA). These modalities were not addressed in our article because we cannot evaluate all lesions with them. Among 1936 lesions evaluated in our study, 110 lesions could not be crossed with guidewire. None of the abovementioned modalities can evaluate these lesions because they can be used only after successful crossing of the guidewire. Because the aim of our article is to evaluate the success and complication rate of BPA according to the location and morphology of thromboembolic lesions to …