Koichiro Sugimura

Acute vasodilator effects of inhaled fasudil, a specific Rho-kinase inhibitor, in patients with pulmonary arterial hypertension

We have previously demonstrated that long-term inhibition of Rho-kinase ameliorates pulmonary arterial hypertension (PAH) in animal models. In the present study, we examined acute vasodilator effects of inhaled fasudil, a specific Rho-kinase inhibitor, as a more feasible option to locally deliver the drug for PAH. We examined 15 patients with PAH (13 women and 2 men, 45 ± 4 years old), including idiopathic PAH (n = 5), PAH associated with connective tissue disease (n = 6), PAH with congenital heart disease (n = 3), and portal PAH (n = 1). In those patients, we performed right heart catheterization with a Swan-Ganz catheter in the two protocols with inhalation of nitric oxide (NO) (40 ppm, 10 min) and fasudil (30 mg, 10 min) with a sufficient interval (>30 min). Both NO and fasudil inhalation significantly reduced mean pulmonary arterial pressure (PAP) (NO: P < 0.01, fasudil: P < 0.05) and tended to decrease pulmonary vascular resistance (NO: P = 0.07, fasudil: P = 0.1), but did not affect cardiac index. The ratio of pulmonary to systemic vascular resistance was significantly reduced both in NO and fasudil inhalation (NO: P < 0.01, fasudil: P < 0.05), indicating that both NO and fasudil inhalation selectively affect lung tissues. Interestingly, there was no correlation in the vasodilator effects between NO and fasudil, and a positive correlation with serum levels of high-sensitivity C-reactive protein was noted for fasudil but not for NO. These results suggest that inhalation of fasudil is as effective as NO in patients with PAH, possibly through different mechanisms.

Statin ameliorates hypoxia-induced pulmonary hypertension associated with down-regulated stromal cell-derived factor-1

AIMS Mobilization of stem cells/progenitors is regulated by the interaction between stromal cell-derived factor-1 (SDF-1) and its ligand, CXC chemokine receptor 4 (CXCR4). Statins have been suggested to ameliorate pulmonary arterial hypertension (PAH); however, the mechanisms involved, especially their effects on progenitors, are largely unknown. Therefore, we examined whether pravastatin ameliorates hypoxia-induced PAH in mice, and if so, which type of progenitors and what mechanism(s) are involved. METHODS AND RESULTS Chronic hypoxia (10% O(2) for 5 weeks) increased the plasma levels of SDF-1 and mobilization of CXCR4(+)/vascular endothelial growth factor receptor (VEGFR)2(+)/c-kit(+) cells from bone marrow (BM) to pulmonary artery adventitia in Balb/c mice in vivo, both of which were significantly suppressed by simultaneous oral treatment with pravastatin (2 mg/kg/day). Furthermore, in vitro experiments demonstrated that hypoxia enhances differentiation of VEGFR2(+)/c-kit(+) cells into alpha-smooth muscle actin(+) cells. Importantly, pravastatin ameliorated hypoxia-induced PAH associated with a decrease in the number of BM-derived progenitors accumulating in the pulmonary artery adventitia. The expression of intercellular adhesion molecule-1 (ICAM-1) and its ligand, CD18 (beta2-integrin), were enhanced by hypoxia and were again suppressed by pravastatin. CONCLUSIONS These results suggest that pravastatin ameliorates hypoxia-induced PAH through suppression of SDF-1/CXCR4 and ICAM-1/CD18 pathways with a resultant reduction in the mobilization and homing of BM-derived progenitor cells.

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.

Enhanced [18F]fluorodeoxyglucose accumulation in the right ventricular free wall predicts long-term prognosis of patients with pulmonary hypertension: a preliminary observational study.

AIMS We have previously demonstrated that [(18)F]fluorodeoxyglucose (FDG) accumulation is increased in the right ventricular (RV) free wall of patients with pulmonary hypertension (PH), and that this accumulation is ameliorated after the treatment with epoprostenol associated with improvement of haemodynamic overload. The aim of this study was to examine whether enhanced RV FDG accumulation by gated positron emission tomography (PET) has a prognostic impact in patients with PH. METHODS AND RESULTS We examined the prognostic impact of the RV standardized uptake value (SUV) of FDG-PET corrected for the partial volume effect (cRV-SUV) in 27 patients with PH who underwent gated FDG-PET from March 2001 to June 2004. During the follow-up period of 69 ± 49 (mean ± SD) months, among the 27 patients, 15 showed clinical worsening (CW) and 11 died. FDG-PET examination showed that cRV-SUV was significantly higher in the CW group compared with the non-CW group (10.1 vs. 7.6, P = 0.02). Univariate Cox hazard analysis showed that cRV-SUV was significantly correlated with the time to CW (hazard ratio 1.25, 95% confidence interval 1.04-1.51, P = 0.02), which remained significant even after adjustment of World Health Organization functional class. Kaplan-Meier analysis showed that the patients with cRV-SUV ≥8.3 had poor prognosis compared with those with cRV-SUV <8.3 (log-rank P = 0.005 for time to CW and P = 0.07 for mortality). CONCLUSION These results indicate that enhanced FDG accumulation in the RV free wall may be a novel prognostic factor in patients with PH.

A novel mutation in PNPLA2 causes neutral lipid storage disease with myopathy and triglyceride deposit cardiomyovasculopathy: A case report and literature review

Mutations in PNPLA2 cause neutral lipid storage disease with myopathy (NLSDM) or triglyceride deposit cardiomyovasculopathy (TGCV). We report a 59-year-old patient with NLSDM/TGCV presenting marked asymmetric skeletal myopathy and cardiomyovasculopathy. Skeletal muscle and endomyocardial biopsies showed cytoplasmic vacuoles containing neutral lipid. Gene analysis revealed a novel homozygous mutation (c.576delC) in PNPLA2. We reviewed 37 genetically-proven NLSDM/TGCV cases; median age was 30 years; distribution of myopathy was proximal (69%) and distal predominant (16%); asymmetric myopathy (right>left) was reported in 41% of the patients. Frequently-affected muscles were posterior compartment of leg (75%), shoulder girdle to upper arm (50%), and paraspinal (33%). Skeletal muscle biopsies showed lipid accumulation in 100% and rimmed vacuoles in 22%. Frequent comorbidities were cardiomyopathy (44%), hyperlipidemia (23%), diabetes mellitus (24%), and pancreatitis (14%). PNPLA2 mutations concentrated in Exon 4-7 without apparent genotype-phenotype correlations. To know the characteristic features is essential for the early diagnosis of NLSDM/TGCV.

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.

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). METHODSANDRESULTS 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 (Pearsons 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).

Three-dimensional-optical coherence tomography imaging of chronic thromboembolic pulmonary hypertension

Chronic thromboembolic pulmonary hypertension (CTEPH) is caused by unresolved thromboemboli in the pulmonary arteries (PAs). We have previously demonstrated the usefulness of optical coherence tomography …

Protective Roles of Endothelial AMP-Activated Protein Kinase Against Hypoxia-Induced Pulmonary Hypertension in Mice

RATIONALE Endothelial AMP-activated protein kinase (AMPK) plays an important role for vascular homeostasis, and its role is impaired by vascular inflammation. However, the role of endothelial AMPK in the pathogenesis of pulmonary arterial hypertension (PAH) remains to be elucidated. OBJECTIVE To determine the role of endothelial AMPK in the development of PAH. METHODS AND RESULTS Immunostaining showed that endothelial AMPK is downregulated in the pulmonary arteries of patients with PAH and hypoxia mouse model of pulmonary hypertension (PH). To elucidate the role of endothelial AMPK in PH, we used endothelial-specific AMPK-knockout mice (eAMPK(-/-)), which were exposed to hypoxia. Under normoxic condition, eAMPK(-/-) mice showed the normal morphology of pulmonary arteries compared with littermate controls (eAMPK(flox/flox)). In contrast, development of hypoxia-induced PH was accelerated in eAMPK(-/-) mice compared with controls. Furthermore, the exacerbation of PH in eAMPK(-/-) mice was accompanied by reduced endothelial function, upregulation of growth factors, and increased proliferation of pulmonary artery smooth muscle cells. Importantly, conditioned medium from endothelial cells promoted pulmonary artery smooth muscle cell proliferation, which was further enhanced by the treatment with AMPK inhibitor. Serum levels of inflammatory cytokines, including tumor necrosis factor-α and interferon-γ were significantly increased in patients with PAH compared with healthy controls. Consistently, endothelial AMPK and cell proliferation were significantly reduced by the treatment with serum from patients with PAH compared with controls. Importantly, long-term treatment with metformin, an AMPK activator, significantly attenuated hypoxia-induced PH in mice. CONCLUSIONS These results indicate that endothelial AMPK is a novel therapeutic target for the treatment of PAH.

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. METHODSANDRESULTS 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.