Endothelial Heterogeneity in the Response to Autophagy Drives Small Vessel Muscularization in Pulmonary Hypertension.

BACKGROUND: Endothelial cell (EC) apoptosis and proliferation of apoptosis-resistant cells is a hallmark of pulmonary hypertension (PH). Yet, why some ECs die and others proliferate and how this contributes to vascular remodeling is unclear. We hypothesized that this differential response may: (1) relate to different EC subsets, namely pulmonary artery (PAECs) versus microvascular ECs (MVECs); (2) be attributable to autophagic activation in both EC subtypes; and (3) cause replacement of MVECs by PAECs with subsequent distal vessel muscularization. METHODS: EC subset responses to chronic hypoxia were assessed by single-cell RNA sequencing of murine lungs. Proliferative versus apoptotic responses, activation, and role of autophagy were assessed in human and rat PAECs and MVECs, and in precision-cut lung slices of wild-type mice or mice with endothelial deficiency in the autophagy gene Atg7 (Atg7EN-KO). Abundance of PAECs versus MVECs in precapillary microvessels was assessed in lung tissue from patients with PH and animal models on the basis of structural or surface markers. RESULTS: In vitro and in vivo, PAECs proliferated in response to hypoxia, whereas MVECs underwent apoptosis. Single-cell RNA sequencing analyses support these findings in that hypoxia induced an antiapoptotic, proliferative phenotype in arterial ECs, whereas capillary ECs showed a propensity for cell death. These distinct responses were prevented in hypoxic Atg7EN-KO mice or after ATG7 silencing, yet replicated by autophagy stimulation. In lung tissue from mice, rats, or patients with PH, the abundance of PAECs in precapillary arterioles was increased, and that of MVECs reduced relative to controls, indicating replacement of microvascular by macrovascular ECs. EC replacement was prevented by genetic or pharmacological inhibition of autophagy in vivo. Conditioned medium from hypoxic PAECs yet not MVECs promoted pulmonary artery smooth muscle cell proliferation and migration in a platelet-derived growth factor-dependent manner. Autophagy inhibition attenuated PH development and distal vessel muscularization in preclinical models. CONCLUSIONS: Autophagic activation by hypoxia induces in parallel PAEC proliferation and MVEC apoptosis. These differential responses cause a progressive replacement of MVECs by PAECs in precapillary pulmonary arterioles, thus providing a macrovascular context that in turn promotes pulmonary artery smooth muscle cell proliferation and migration, ultimately driving distal vessel muscularization and the development of PH.

ADAMTS8 Promotes the Development of Pulmonary Arterial Hypertension and Right Ventricular Failure: A Possible Novel Therapeutic Target.

RATIONALE: Pulmonary arterial hypertension (PAH) is characterized by pulmonary vascular remodeling with aberrant pulmonary artery smooth muscle cells (PASMCs) proliferation, endothelial dysfunction, and extracellular matrix remodeling. OBJECTIVE: Right ventricular (RV) failure is an important prognostic factor in PAH. Thus, we need to elucidate a novel therapeutic target in both PAH and RV failure. METHODS AND RESULTS: We performed microarray analysis in PASMCs from patients with PAH (PAH-PASMCs) and controls. We found a ADAMTS8 (disintegrin and metalloproteinase with thrombospondin motifs 8), a secreted protein specifically expressed in the lung and the heart, was upregulated in PAH-PASMCs and the lung in hypoxia-induced pulmonary hypertension (PH) in mice. To elucidate the role of ADAMTS8 in PH, we used vascular smooth muscle cell-specific ADAMTS8-knockout mice (ADAMTSΔSM22). Hypoxia-induced PH was attenuated in ADAMTSΔSM22 mice compared with controls. ADAMTS8 overexpression increased PASMC proliferation with downregulation of AMPK (AMP-activated protein kinase). In contrast, deletion of ADAMTS8 reduced PASMC proliferation with AMPK upregulation. Moreover, deletion of ADAMTS8 reduced mitochondrial fragmentation under hypoxia in vivo and in vitro. Indeed, PASMCs harvested from ADAMTSΔSM22 mice demonstrated that phosphorylated DRP-1 (dynamin-related protein 1) at Ser637 was significantly upregulated with higher expression of profusion genes (Mfn1 and Mfn2) and improved mitochondrial function. Moreover, recombinant ADAMTS8 induced endothelial dysfunction and matrix metalloproteinase activation in an autocrine/paracrine manner. Next, to elucidate the role of ADAMTS8 in RV function, we developed a cardiomyocyte-specific ADAMTS8 knockout mice (ADAMTS8ΔαMHC). ADAMTS8ΔαMHC mice showed ameliorated RV failure in response to chronic hypoxia. In addition, ADAMTS8ΔαMHC mice showed enhanced angiogenesis and reduced RV ischemia and fibrosis. Finally, high-throughput screening revealed that mebendazole, which is used for treatment of parasite infections, reduced ADAMTS8 expression and cell proliferation in PAH-PASMCs and ameliorated PH and RV failure in PH rodent models. CONCLUSIONS: These results indicate that ADAMTS8 is a novel therapeutic target in PAH.

Diagnostic and Prognostic Significance of Serum Levels of SeP (Selenoprotein P) in Patients With Pulmonary Hypertension.

OBJECTIVE: Despite the recent progress in upfront combination therapy for pulmonary arterial hypertension (PAH), useful biomarkers for the disorder still remain to be developed. SeP (Selenoprotein P) is a glycoprotein secreted from various kinds of cells including pulmonary artery smooth muscle cells to maintain cellular metabolism. We have recently demonstrated that SeP production from pulmonary artery smooth muscle cells is upregulated and plays crucial roles in the pathogenesis of PAH. However, it remains to be elucidated whether serum SeP levels could be a useful biomarker for PAH. Approach and Results: We measured serum SeP levels and evaluated their prognostic impacts in 65 consecutive patients with PAH and 20 controls during follow-up (mean, 1520 days; interquartile range, 1393-1804 days). Serum SeP levels were measured using a newly developed sol particle homogeneous immunoassay. The patients with PAH showed significantly higher serum SeP levels compared with controls. Higher SeP levels (cutoff point, 3.47 mg/L) were associated with the outcome (composite end point of all-cause death and lung transplantation) in patients with PAH (hazard ratio, 4.85 [1.42-16.6]; P<0.01). Importantly, we found that the absolute change in SeP of patients with PAH (ΔSeP) in response to the initiation of PAH-specific therapy significantly correlated with the absolute change in mean pulmonary artery pressure, pulmonary vascular resistance (ΔPVR), and cardiac index (ΔCI; R=0.78, 0.76, and -0.71 respectively, all P<0.0001). Moreover, increase in ΔSeP during the follow-up predicted poor outcome of PAH. CONCLUSIONS: Serum SeP is a novel biomarker for diagnosis and assessment of treatment efficacy and long-term prognosis in patients with PAH.

Selenoprotein P Promotes the Development of Pulmonary Arterial Hypertension: Possible Novel Therapeutic Target.

BACKGROUND: Excessive proliferation and apoptosis resistance of pulmonary artery smooth muscle cells (PASMCs) are key mechanisms of pulmonary arterial hypertension (PAH). Despite the multiple combination therapy, a considerable number of patients develop severe pulmonary hypertension (PH) because of the lack of diagnostic biomarker and antiproliferative therapies for PASMCs. METHODS: Microarray analyses were used to identify a novel therapeutic target for PAH. In vitro experiments, including lung and serum samples from patients with PAH, cultured PAH-PASMCs, and high-throughput screening of 3336 low-molecular-weight compounds, were used for mechanistic study and exploring a novel therapeutic agent. Five genetically modified mouse strains, including PASMC-specific selenoprotein P (SeP) knockout mice and PH model rats, were used to study the role of SeP and therapeutic capacity of the compounds for the development of PH in vivo. RESULTS: Microarray analysis revealed a 32-fold increase in SeP in PAH-PASMCs compared with control PASMCs. SeP is a widely expressed extracellular protein maintaining cellular metabolism. Immunoreactivity of SeP was enhanced in the thickened media of pulmonary arteries in PAH. Serum SeP levels were also elevated in patients with PH compared with controls, and high serum SeP predicted poor outcome. SeP-knockout mice ( SeP-/-) exposed to chronic hypoxia showed significantly reduced right ventricular systolic pressure, right ventricular hypertrophy, and pulmonary artery remodeling compared with controls. In contrast, systemic SeP-overexpressing mice showed exacerbation of hypoxia-induced PH. Furthermore, PASMC-specific SeP-/- mice showed reduced hypoxia-induced PH compared with controls, whereas neither liver-specific SeP knockout nor liver-specific SeP-overexpressing mice showed significant differences with controls. Altogether, protein levels of SeP in the lungs were associated with the development of PH. Mechanistic experiments demonstrated that SeP promotes PASMC proliferation and resistance to apoptosis through increased oxidative stress and mitochondrial dysfunction, which were associated with activated hypoxia-inducible factor-1α and dysregulated glutathione metabolism. It is important to note that the high-throughput screening of 3336 compounds identified that sanguinarine, a plant alkaloid with antiproliferative effects, reduced SeP expression and proliferation in PASMCs and ameliorated PH in mice and rats. CONCLUSIONS: These results indicate that SeP promotes the development of PH, suggesting that it is a novel biomarker and therapeutic target of the disorder.

Activated TAFI Promotes the Development of Chronic Thromboembolic Pulmonary Hypertension: A Possible Novel Therapeutic Target.

RATIONALE: Pulmonary hypertension is a fatal disease; however, its pathogenesis still remains to be elucidated. Thrombin-activatable fibrinolysis inhibitor (TAFI) is synthesized by the liver and inhibits fibrinolysis. Plasma TAFI levels are significantly increased in chronic thromboembolic pulmonary hypertension (CTEPH) patients. OBJECTIVE: To determine the role of activated TAFI (TAFIa) in the development of CTEPH. METHODS AND RESULTS: Immunostaining showed that TAFI and its binding partner thrombomodulin (TM) were highly expressed in the pulmonary arteries (PAs) and thrombus in patients with CTEPH. Moreover, plasma levels of TAFIa were increased 10-fold in CTEPH patients compared with controls. In mice, chronic hypoxia caused a 25-fold increase in plasma levels of TAFIa with increased plasma levels of thrombin and TM, which led to thrombus formation in PA, vascular remodeling, and pulmonary hypertension. Consistently, plasma clot lysis time was positively correlated with plasma TAFIa levels in mice. Additionally, overexpression of TAFIa caused organized thrombus with multiple obstruction of PA flow and reduced survival rate under hypoxia in mice. Bone marrow transplantation showed that circulating plasma TAFI from the liver, not in the bone marrow, was activated locally in PA endothelial cells through interactions with thrombin and TM. Mechanistic experiments demonstrated that TAFIa increased PA endothelial permeability, smooth muscle cell proliferation, and monocyte/macrophage activation. Importantly, TAFIa inhibitor and peroxisome proliferator-activated receptor-α agonists significantly reduced TAFIa and ameliorated animal models of pulmonary hypertension in mice and rats. CONCLUSIONS: These results indicate that TAFIa could be a novel biomarker and realistic therapeutic target of CTEPH.

Beneficial Effects of Imatinib in a Patient with Suspected Pulmonary Veno-Occlusive Disease.

Pulmonary veno-occlusive disease (PVOD) is a rare form of pulmonary hypertension (PH). The prognosis of PVOD patients remains poor, since no effective medical therapy is yet available. Imatinib is a tyrosine kinase inhibitor specific for platelet-derived growth factor receptor and is expected as a treatment option for pulmonary arterial hypertension (PAH). Recently, it has been reported that imatinib improved functional capacity of a patient with PVOD. We here report a patient with suspected PVOD who has been successfully treated with imatinib and is alive for 6 years after diagnosis. A 57-year-old woman was admitted to a hospital for severe dyspnea. Echocardiography suggested the presence of PH, because tricuspid regurgitation pressure gradient was elevated. The patient was then transferred to our hospital by an ambulance ahead of schedule due to fever and worsening dyspnea. Because the patient had no left heart disease, we diagnosed that she had PAH associated with severe right heart failure. We immediately started treatment with nitric oxide (NO) for her severe hypoxia; however, it caused pulmonary edema. We suspected PVOD from CT characteristics and pulmonary edema after PAH-targeted vasodilator therapy, and then started oral imatinib treatment. In response to imatinib, her pulmonary edema gradually improved. Since then, the patient has been alive for 6 years with imatinib and pulmonary vasodilators. At present, lung transplantation is the only effective therapy for PVOD with limited availability. We therefore propose that imatinib may be a treatment option for PVOD and a bridge to lung transplantation.

Prognostic Impacts of Plasma Levels of Cyclophilin A in Patients With Coronary Artery Disease.

OBJECTIVE: Cyclophilin A (CyPA) is secreted from vascular smooth muscle cells, inflammatory cells, and activated platelets in response to oxidative stress. We have recently demonstrated that plasma CyPA level is a novel biomarker for diagnosing coronary artery disease. However, it remains to be elucidated whether plasma CyPA levels also have a prognostic impact in such patients. APPROACH AND RESULTS: In 511 consecutive patients undergoing diagnostic coronary angiography, we measured the plasma levels of CyPA, high-sensitivity C-reactive protein (hsCRP), and brain natriuretic peptide and evaluated their prognostic impacts during the follow-up (42 months, interquartile range: 25-55 months). Higher CyPA levels (≥12 ng/mL) were significantly associated with all-cause death, rehospitalization, and coronary revascularization. Higher hsCRP levels (≥1 mg/L) were also significantly correlated with the primary end point and all-cause death, but not with rehospitalization or coronary revascularization. Similarly, higher brain natriuretic peptide levels (≥100 pg/mL) were significantly associated with all-cause death and rehospitalization, but not with coronary revascularization. Importantly, the combination of CyPA (≥12 ng/mL) and hsCRP (≥1 mg/L) was more significantly associated with all-cause death (hazard ratio, 21.2; 95% confidence interval, 4.9-92.3,; P<0.001) than CyPA (≥12 ng/mL) or hsCRP (≥1 mg/L) alone. CONCLUSIONS: The results indicate that plasma CyPA levels can be used to predict all-cause death, rehospitalization, and coronary revascularization in patients with coronary artery disease and that when combined with other biomarkers (hsCRP and brain natriuretic peptide levels), the CyPA levels have further enhanced prognostic impacts in those patients.

Sex differences in hemodynamic responses and long-term survival to optimal medical therapy in patients with pulmonary arterial hypertension.

It is widely known that the incidence of pulmonary arterial hypertension (PAH) is higher in female, whereas prognosis is poorer in male patients. However, sex differences in hemodynamic response to and long-term prognosis with PAH-targeted treatment in the modern era remain to be fully elucidated. We examined the long-term prognosis of 129 consecutive PAH patients (34 males and 95 females) diagnosed in our hospital from April 1999 to October 2014, and assessed hemodynamic changes in response to PAH-targeted therapy. Female patients had better 5-year survival compared with male patients (74.0 vs. 53.4%, P = 0.003); however, higher age quartiles in females were associated with poor outcome. Follow-up examination after medical treatment showed significant decreases in mean pulmonary arterial pressure (mPAP), pulmonary vascular resistance (PVR), and pulmonary arterial capacitance (PAC) in both sexes (both P < 0.05), whereas only females had a significant improvement in right ventricular end-diastolic pressure (RVEDP), right atrial pressure (RAP), cardiac index, and mixed venous oxygen saturation (SvO2) (all P < 0.05). Baseline age significantly correlated with the hemodynamic changes only in female patients; particularly, there were significant sex interactions in RVEDP and RAP (both P < 0.10). The multivariable analysis showed that SvO2 at baseline and mPAP and SvO2 at follow-up were significant prognostic factors in males, whereas the changes in mPAP, PVR, and PAC and use of endothelin-receptor antagonist in females. These results indicate that female PAH patients have better long-term prognosis than males, for which better improvements of right ventricular functions and hemodynamics may be involved.

Comprehensive evaluation of the effectiveness and safety of balloon pulmonary angioplasty for inoperable chronic thrombo-embolic pulmonary hypertension: long-term effects and procedure-related complications.

AIMS: Although balloon pulmonary angioplasty (BPA) improves haemodynamics and short-term prognosis in patients with inoperable chronic thrombo-embolic pulmonary hypertension (CTEPH), the long-term effects of BPA, and procedure-related complications remain to be fully elucidated. METHODS AND RESULTS: From July 2009 to October 2016, we performed a total of 424 BPA sessions in 84 consecutive patients with inoperable CTEPH. We used 3D reconstructed computed tomography to determine target lesions of pulmonary arteries and optical computed tomography to select balloon size, if needed. In 77 patients (92%) who completed the BPA treatment [65 ± 14 (SD) years-old, male/female 14/63], haemodynamics and exercise capacity were examined at 6 months after last BPA and in the chronic phase [>12 months after first BPA, 31 (20, 41) months]. The BPA treatment significantly improved mean pulmonary arterial pressure (38 ± 10 to 25 ± 6 mmHg), pulmonary vascular resistance (7.3 ± 3.2 to 3.8 ± 1.0 Wood units), and 6-minute walk distance (380 ± 138 to 486 ± 112 m) (all P < 0.01), and the improvements persisted throughout the follow-up period (43 ± 27 months) (N = 53). In the 424 sessions, haemoptysis was noted in 60 sessions (14%), and non-invasive positive pressure ventilation (NPPV) was used to treat haemoptysis and/or hypoxemia in 33 sessions (8%). Furthermore, 5-year survival was 98.4% (only one patient died of colon cancer) with no peri-procedural death. CONCLUSION: These results indicate that BPA improves haemodynamics and exercise capacity in inoperable CTEPH patients with acceptable complication rate and that the beneficial haemodynamic effects of BPA persist for years with resultant good long-term prognosis.

Identification of Novel Therapeutic Targets for Pulmonary Arterial Hypertension.

Pulmonary arterial hypertension (PAH) and chronic thromboembolic pulmonary hypertension (CTEPH) are fatal diseases; however, their pathogenesis still remains to be elucidated. We have recently screened novel pathogenic molecules and have performed drug discovery targeting those molecules. Pulmonary artery smooth muscle cells (PASMCs) in patients with PAH (PAH-PASMCs) have high proliferative properties like cancer cells, which leads to thickening and narrowing of distal pulmonary arteries. Thus, we conducted a comprehensive analysis of PAH-PASMCs and lung tissues to search for novel pathogenic proteins. We validated the pathogenic role of the selected proteins by using tissue-specific knockout mice. To confirm its clinical significance, we used patient-derived blood samples to evaluate the potential as a biomarker for diagnosis and prognosis. Finally, we conducted a high throughput screening and found inhibitors for the pathogenic proteins.

Thrombin-Activatable Fibrinolysis Inhibitor in Chronic Thromboembolic Pulmonary Hypertension.

OBJECTIVE: The pathogenesis of chronic thromboembolic pulmonary hypertension (CTEPH) remains to be elucidated. Thrombin-activatable fibrinolysis inhibitor (TAFI) inhibits fibrinolysis. It remains to be elucidated whether TAFI is directly involved in the pathogenesis of CTEPH. We examined potential involvement of TAFI in the pathogenesis of CTEPH in humans. APPROACH AND RESULTS: We enrolled 68 consecutive patients undergoing right heart catheterization in our hospital, including those with CTEPH (n=27), those with pulmonary arterial hypertension (n=22), and controls (non-pulmonary hypertension, n=19). Whole blood clot lysis assay showed that the extent of clot remaining after 4 hours was significantly higher in CTEPH compared with pulmonary arterial hypertension or controls (41.9 versus 26.5 and 24.6%, both P<0.01). Moreover, plasma levels of TAFI were significantly higher in CTEPH than in pulmonary arterial hypertension or controls (19.4±4.2 versus 16.1±4.5 or 16.3±3.3 µg/mL, both P<0.05), which remained unchanged even after hemodynamic improvement by percutaneous transluminal pulmonary angioplasty. Furthermore, the extent of clot remaining after 4 hours was significantly improved with CPI-2KR (an inhibitor of activated TAFI) or prostaglandin E1 (an inhibitor of activation of platelets). Importantly, plasma levels of TAFI were significantly correlated with the extent of clot remaining after 4 hours. In addition, the extent of clot remaining after 4 hours was improved with an activated TAFI inhibitor. CONCLUSIONS: These results indicate that plasma levels of TAFI are elevated in patients with CTEPH and are correlated with resistance to clot lysis in those patients.

Basigin mediates pulmonary hypertension by promoting inflammation and vascular smooth muscle cell proliferation.

RATIONALE: Cyclophilin A (CyPA) is secreted from vascular smooth muscle cells (VSMCs) by oxidative stress and promotes VSMC proliferation. However, the role of extracellular CyPA and its receptor Basigin (Bsg, encoded by Bsg) in the pathogenesis of pulmonary hypertension (PH) remains to be elucidated. OBJECTIVE: To determine the role of CyPA/Bsg signaling in the development of PH. METHODS AND RESULTS: In the pulmonary arteries of patients with PH, immunostaining revealed strong expression of CyPA and Bsg. The pulmonary arteries of CyPA(±) and Bsg(±) mice exposed to normoxia did not differ in morphology compared with their littermate controls. In contrast, CyPA(±) and Bsg(±) mice exposed to hypoxia for 4 weeks revealed significantly reduced right ventricular systolic pressure, pulmonary artery remodeling, and right ventricular hypertrophy compared with their littermate controls. These features were unaltered by bone marrow reconstitution. To further evaluate the role of vascular Bsg, we harvested pulmonary VSMCs from Bsg(+/+) and Bsg(±) mice. Proliferation was significantly reduced in Bsg(±) compared with Bsg(+/+) VSMCs. Mechanistic studies demonstrated that Bsg(±) VSMCs revealed reduced extracellular signal-regulated kinase 1/2 activation and less secretion of cytokines/chemokines and growth factors (eg, platelet-derived growth factor-BB). Finally, in the clinical study, plasma CyPA levels in patients with PH were increased in accordance with the severity of pulmonary vascular resistance. Furthermore, event-free curve revealed that high plasma CyPA levels predicted poor outcome in patients with PH. CONCLUSIONS: These results indicate the crucial role of extracellular CyPA and vascular Bsg in the pathogenesis of PH.

Multiple Beneficial Effects of Balloon Pulmonary Angioplasty in Patients With Chronic Thromboembolic Pulmonary Hypertension.

BACKGROUND: Pulmonary arterial hypertension with systemic dysfunctions, including metabolic disorders and renal dysfunction, has a poor prognosis. However, it remains to be elucidated whether chronic thromboembolic pulmonary hypertension (CTEPH) is also associated with systemic dysfunctions, and if so, whether balloon pulmonary angioplasty (BPA) improves them. METHODS AND RESULTS: Fifty-five consecutive patients who underwent BPA from March 2012 to December 2014 for systemic dysfunctions, including glycemic control, lipid profiles, renal and vascular function, and nutritional status were examined. The analyses were performed before and after BPA (mean, 3.5 sessions/patient) and changes in hemodynamic parameters were compared. The average follow-up period was 474±245 days. Baseline prevalence of hypertension, diabetes mellitus, dyslipidemia and advanced chronic kidney disease was 58, 7, 33 and 36%, respectively. BPA caused marked hemodynamic improvements in the CTEPH patients. Importantly, BPA also significantly improved dysglycemia (fasting blood sugar, hemoglobin A1c and homeostatic assessment model of insulin resistance), renal (creatinine and estimated glomerular filtration rate) and vascular (cardio-ankle vascular index) functions and nutritional status (albumin, cholesterols, and body mass index). Importantly, there were positive correlations between the degrees of the hemodynamic improvements and those of other improvements. CONCLUSIONS: These results indicate that BPA may exert multiple beneficial effects in CTEPH patients, not only in terms of hemodynamics but also in other systemic functions, with positive correlations among them.

Balloon Pulmonary Angioplasty Improves Biventricular Functions and Pulmonary Flow in Chronic Thromboembolic Pulmonary Hypertension.

BACKGROUND: It remains to be determined whether balloon pulmonary angioplasty (BPA) improves biventricular cardiac functions and pulmonary flow in patients with chronic thromboembolic pulmonary hypertension (CTEPH). METHODS AND RESULTS: We enrolled 30 consecutive patients with inoperable CTEPH who underwent BPA, and carried out serial cardiac magnetic resonance imaging (CMR; M/F, 9/21; median age, 65.2 years). No patient died during the treatment or follow-up period. BPA significantly improved WHO functional class (III/IV, 83.0 to 4.0%), 6-min walking distance (330.2±168.7 to 467.3±114.4 m), mean pulmonary artery pressure (40.8±10.7 to 23.2±4.94 mmHg), pulmonary vascular resistance (9.26±4.19 to 3.35±1.40 WU) and cardiac index (2.19±0.64 to 2.50±0.57 L·min·m(2); all P<0.01). CMR also showed improvement of right ventricular (RV) ejection fraction (EF; 41.3±12.4 to 50.7±8.64%), left ventricular (LV) end-diastolic volume index (72.1±14.0 to 81.6±18.6 ml/m(2)) and LV stroke volume index (41.0±9.25 to 47.8±12.3 ml/m(2); all P<0.01). There was a significant correlation between change in RVEF and LVEF (Pearson's r=0.45, P=0.01). Average velocity in the main pulmonary artery was also significantly improved (7.50±2.43 to 9.79±2.92 cm/s, P<0.01). CONCLUSIONS: BPA improves biventricular functions and pulmonary flow in patients with inoperable CTEPH. (Circ J 2016; 80: 1470-1477).

Focal Reduction in Cardiac 123I-Metaiodobenzylguanidine Uptake in Patients With Anderson-Fabry Disease.

BACKGROUND: It remains to be elucidated whether cardiac sympathetic nervous activity is impaired in patients with Anderson-Fabry disease (AFD).Methods and Results:We performed 123I-meta-iodobenzylguanidine (MIBG) scintigraphy and gadolinium-enhanced cardiovascular magnetic resonance (CMR) in 5 AFD patients. MIBG uptake in the inferolateral wall, where wall thinning and delayed enhancement were noted on CMR, was significantly lower compared with the anteroseptal wall. The localized reduction in MIBG uptake was also noted in 2 patients with no obvious abnormal findings on CMR. CONCLUSIONS: Cardiac sympathetic nervous activity is impaired in AFD before development of structural myocardial abnormalities. (Circ J 2016; 80: 2550-2551).

Effects of Balloon Pulmonary Angioplasty on Oxygenation in Patients With Chronic Thromboembolic Pulmonary Hypertension　- Importance of Intrapulmonary Shunt.

BACKGROUND: Although balloon pulmonary angioplasty (BPA) improves the hemodynamics and prognosis of patients with inoperable chronic thromboembolic pulmonary hypertension (CTEPH), the mechanisms of improvement in oxygenation remain to be elucidated. METHODS AND RESULTS: From August 2013 to May 2015, we performed a total of 113 BPA procedures in 24 patients with inoperable CTEPH (mean 4.7 procedures per patient). Median age was 70 [60, 74] years and 18 were female (75%). We examined hemodynamics, respiratory functions, and intrapulmonary shunt before and after the BPA procedure. Mean pulmonary arterial pressure (37 [28, 45] to 23[19, 27] mmHg, P<0.01), pulmonary vascular resistance (517 [389, 696] to 268 [239, 345] dyne/s/cm(5)) and 6-min walk distance (390 [286, 484] to 490 [411, 617] m, P<0.01) were significantly improved after BPA therapy. Furthermore, arterial oxygen partial pressure (PaO2, 54.8 [50.0, 60.8] to 65.2 [60.6, 73.2] %, P<0.01) and intrapulmonary shunt (23.4±6.0% to 19.3±5.0%, P<0.01) were also significantly ameliorated. In the multivariate analysis, decrease in intrapulmonary shunt after BPA was significantly correlated with improvement of both PaO2(r(2)=0.26, P<0.01) and SaO2(r(2)=0.49, P<0.01) after BPA. CONCLUSIONS: These results indicated that BPA improved not only pulmonary hemodynamics but also oxygenation with a resultant decrease in intrapulmonary shunt. (Circ J 2016; 80: 2227-2234).

Platelets are highly activated in patients of chronic thromboembolic pulmonary hypertension.

OBJECTIVE: Chronic thromboembolic pulmonary hypertension (CTEPH) is a fatal disease that is distinct from pulmonary arterial hypertension (PAH). Although CTEPH is characterized by obstruction of major pulmonary artery because of chronic thrombus, it remains unclear whether CTEPH is associated with prothrombotic condition. APPROACH AND RESULTS: In addition to conventional markers, GTP-bound levels of Rap1, RhoA, RalA, Rac1, and Ras in platelets, which are implicated for platelet activation, were measured in patients without pulmonary hypertension (non-PH, n=15), patients with PAH (n=19), and patients with CTEPH (n=25). Furthermore, the responsiveness to ex vivo thrombin stimulation was also evaluated. The ratios of the P-selectin positive platelets in the non-PH patients, patients with PAH, and patients with CTEPH were 1.40% (median and interquartile range, 0.83-1.82), 2.40% (1.80-3.39), and 2.63% (1.90-8.22), respectively (non-PH versus CTEPH, P<0.01). The activated GPIIb/IIIa-positive platelets were 6.01% (1.34-7.87), 11.39% (5.69-20.86), and 9.74% (7.83-24.01), respectively (non-PH versus CTEPH, P=0.01). GTP-bound RhoA was 1.79% (0.94-2.83), 4.03% (2.01-5.14), and 2.01% (1.22-2.48), respectively (non-PH versus PAH, P=0.04), and GTP-bound RalA was 1.58% (1.08-2.11), 3.02% (2.03-3.54), and 2.64% (1.42-4.28), respectively (non-PH versus PAH, P=0.023; non-PH versus CTEPH, P=0.048). In contrast, Rac1, Rap1, or Ras was not activated in any groups. The platelets of patients with CTEPH exhibited hyperresponsiveness to ex vivo thrombin stimulation compared with those of non-PH patients when evaluated for the surface markers. Either D-dimer or fibrin degradation product level was not increased in patients with CTEPH. CONCLUSIONS: These results provide the first direct evidence that platelets of patients with CTEPH are highly activated and exhibit hyperresponsiveness to thrombin stimulation.

Evaluating haemodynamic changes: vericiguat in patients with heart failure with reduced ejection fraction.

AIMS: Vericiguat has been used to treat patients with heart failure with reduced ejection fraction (HFrEF) who demonstrated worsening heart failure despite treatment with other guideline-directed medical therapies. The haemodynamic effects of vericiguat remain unclear. METHODS AND RESULTS: This study enrolled 12 patients (median age, 63 [quartiles 53.5, 70] years; 16.7%(N=2) women) with symptomatic HFrEF (New York Heart Association functional class II-IV) who demonstrated worsening heart failure despite treatment with the four foundational guideline-recommended therapies between March and December 2022, with follow-ups completed in June 2023. A balloon-tipped pulmonary artery thermodilution catheter was placed in the right internal jugular vein to perform right heart catheterisation (RHC) on day 1. Haemodynamic data were acquired before and after vericiguat intake (2.5 mg) on days 2 and 3. The data on days 2 and 3 were averaged. RHC was repeated on day 105 (37, 168). Oral intake of vericiguat 2.5 mg decreased mean pulmonary artery pressure (19.3 [14.3, 26.8] mmHg) and pulmonary artery wedge pressure (PAWP) (11 [7.5, 15] mmHg) before the intake to mean pulmonary artery pressure (17.5 [12.5, 24] mmHg) and PAWP (9.3 [6.8, 14] mmHg) at 30 min after (both P < 0.05). Reduction in PAWP was also found from 14.5 [9.5, 19.5] mmHg on day 1 to 9.5 [6.5, 12.5] mmHg on day 105 (37, 168) (P < 0.05), when vericiguat was titrated to 2.5 mg 25% (N = 3), 5 mg 50% (N = 6), and 10 mg 25% (N = 3). CONCLUSIONS: The consistent reduction in PAWP underscores the well-tolerated nature of vericiguat and its potential to enhance cardiac performance in patients with HFrEF.