BACKGROUND: Pulmonary artery compliance (PAC), which could be estimated with gas exchange pulmonary arterial capacitance (GXcap), reflects the elasticity of the pulmonary vessels, and it is known that PAC is changed by pulmonary perfusion. GXcap could be measured using ventilatory gas analysis and is calculated using O2 pulse × peak end-tidal CO2 pressure. Moreover, it is known that pulmonary perfusion by postural changes is different between chronic thromboembolic pulmonary hypertension (CTEPH) and pulmonary arterial hypertension (PAH). However, it was unclear whether GXcap could estimate PAC in CTEPH and PAH. Furthermore, it was unclear that change in GXcap with postural change (ΔGXcap) [Δ (Sitting - Supine)] was different between CTEPH and PAH. METHODS: Patients with suspected pulmonary hypertension who underwent right heart catheterization (RHC) from May 2022 to February 2023 in our institution were prospectively enrolled. Ventilatory gas analysis was performed before RHC in both the supine and sitting positions and calculated. Moreover, PAC was calculated with RHC. The diagnosis of PAH and CTEPH was based on the European Society of Cardiology/European Respiratory Society 2022 guidelines. RESULTS: Forty patients (CTEPH, n = 18; PAH, n = 22) were enrolled in this study. GXcap was positively related to PAC in these patients (R = 0.62, p < 0.001). Furthermore, PAC was significantly lower in CTEPH patients compared to PAH patients (median 1.63 mL/mmHg vs 2.05 mL/mmHg, p = 0.013). Moreover, GXcap was increased in CTEPH patients with postural change, while GXcap was decreased in PAH patients with postural change. Thus, ΔGXcap was significantly higher in CTEPH patients compared to PAH patients (median 5.8 mL × mmHg vs -2.6 mL × mmHg, p = 0.005). CONCLUSIONS: It was suggested that PAC could be moderately estimated using GXcap in PAH and CTEPH patients. Moreover, it was suggested that ΔGXcap was higher in CTEPH patients compared with PAH patients.

Hypopituitarism has been reported in patients receiving continuous infusions of prostaglandin I2 (PGI2) analogues for pulmonary hypertension (PH). However, these patients' clinical characteristics, treatment, and prognoses remain unclear. This retrospective multicentre study included 22 patients who developed hypopituitarism while on continuous PGI2 analogue infusion between 1999 and 2021. All patients were female, and idiopathic pulmonary arterial hypertension was the most common underlying condition (63.6%). Their mean age was 38.8 ± 7.9 years. Epoprostenol was the predominant PGI2 analogue used (90.9%). At the time of hypopituitarism onset, the median PGI2 dose was 67.2 ng/kg/min (31.8-88.7 ng/kg/min), and the median treatment duration was 889.0 days (450.5-1941.5 days), suggesting that hypopituitarism occurred independent of its dose or treatment duration. Diagnoses were based on decreased adrenocorticotropic hormone levels. The hypopituitarism classification revealed isolated pituitary dysfunction in 54.5% of the cases, partial dysfunction in 18.1%, and complete dysfunction in 27.2%. Most cases could be managed without requiring specific therapies. After hypopituitarism onset, 63.6% of the patients continued to receive the same PGI2 analogue. Hydrocortisone therapy was administered to 81.8% of the patients, leading to clinical stabilisation. No deaths were reported. In conclusions, hypopituitarism may occur during continuous PGI2 analogue infusion for PH, irrespective of its dose or treatment duration. Initiating hydrocortisone therapy may be important for stabilising the clinical course.

A 69-year-old woman presented with heart failure and progressive muscle weakness and was diagnosed as anti-mitochondrial antibody (AMA) myositis with cardiac involvement. Immunosuppressive therapy with prednisolone and intravenous cyclophosphamide significantly improved the symptoms, hemodynamics, and cardiac function. Cardiac magnetic resonance (CMR) T1 and T2 mapping showed elevated native T1, T2, and extracellular volume fractions during heart failure exacerbation (day 37) compared to pre-hospitalization values (10 months before admission) and follow-up conducted 6 and 12 months after admission. This case underscores the importance of comprehensive evaluation, such as serial CMR imaging and immunosuppressive therapy, in managing myocardial involvement in AMA-positive myositis.

BACKGROUND: Balloon pulmonary angioplasty (BPA) has exhibited substantial progress in the management of chronic thromboembolic pulmonary hypertension (CTEPH). However, nearly one-half of the patients with CTEPH experience persistent pulmonary hypertension after undergoing BPA, emphasizing the need for enhanced therapies. OBJECTIVES: The authors sought to investigate the clinical significance of functional assessment-guided dilation of the pulmonary artery (PA) in patients with CTEPH undergoing BPA treatment. METHODS: The prospective single-center cohort study enrolled 95 patients who underwent 278 consecutive BPA sessions. Lung parenchymal perfusion was assessed via 2-dimensional perfusion angiography, and pressure catheter measurements were taken to determine the PA pressure ratios. The correlation between lung perfusion and the pressure ratio was analyzed to establish an optimal target pressure ratio. Patients were stratified into 2 groups, a pressure-guided group (n = 28) and an angiographic group (n = 63), to evaluate whether optimizing the pressure ratio led to improvements in residual PH and complications. RESULTS: The pressure ratio and lung perfusion measurements of 141 PA lesions were analyzed. A piecewise linear regression model identified a target pressure ratio of 0.7, associated with significant enhancement in lung perfusion. The pressure-guided strategy achieved a higher rate of mean pulmonary artery pressure <25 mm Hg (92.8% [26/28 patients] vs 60.3% [38/63 patients]; P = 0.001) and a concurrent reduction in BPA relevant complications (3.9% [4/101 sessions] vs 12.9% [23/177 sessions]; P = 0.019). CONCLUSIONS: Functional assessment-guided PA dilation with a target pressure ratio of 0.7 proved beneficial in BPA treatment for patients with CTEPH. This approach improved the residual PH and reduced complications, highlighting its potential to enhance CTEPH management outcomes.

Patients with borderline pulmonary hypertension (PH) often experience shortness of breath or exacerbation of PH during exercise, known as exercise-induced PH. However, the pathogenesis of exercise-induced post-capillary PH (post-EIPH) and its treatment strategies remain unclear. Recent guidelines and consensus documents have highlighted the benefits of sodium-glucose cotransporter-2 (SGLT2) inhibitors in heart failure and chronic kidney disease (CKD). This study aimed to investigate the effects of SGLT2 inhibitors in patients with post-EIPH and CKD. This single-center prospective cohort study enroled 10 patients with CKD (age, 68 years; female, 60%) who exhibited post-EIPH between 1 July 2022 and 31 December 2023. Post-EIPH was defined as a pulmonary capillary wedge pressure (PCWP)/cardiac output (CO) slope > 2 and peak PCWP during exercise ≥ 25 mmHg measured by catheterization. The patients received SGLT2 inhibitor treatment for 6 months. At rest, patients with post-EIPH had borderline-PH (21.5 ± 1.8 mmHg), with preserved left and right ventricular function. SGLT2 inhibitors treatment significantly reduced the PCWP/CO slope during exercise (3.9 ± 1.2 vs. 2.4 ± 1.2 mmHg/L/min, p = 0.013) and improved the 6-min walking distance (489.9 ± 80.2 vs. 568.3 ± 91.9 m, p = 0.014). Magnetic resonance imaging revealed a lower left ventricular global longitudinal strain in patients with post-EIPH, which was increased by SGLT2 inhibitor treatment (-13.8 ± 2.0 vs. -17.3 ± 2.0%, p = 0.003). SGLT2 treatment inhibitors mitigated post-EIPH hemodynamic abnormalities and exercise intolerance, suggesting their potential as its therapeutic option.

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.

Hypoxic reprogramming of vasculature relies on genetic, epigenetic, and metabolic circuitry, but the control points are unknown. In pulmonary arterial hypertension (PAH), a disease driven by hypoxia inducible factor (HIF)-dependent vascular dysfunction, HIF-2α promoted expression of neighboring genes, long noncoding RNA (lncRNA) histone lysine N-methyltransferase 2E-antisense 1 (KMT2E-AS1) and histone lysine N-methyltransferase 2E (KMT2E). KMT2E-AS1 stabilized KMT2E protein to increase epigenetic histone 3 lysine 4 trimethylation (H3K4me3), driving HIF-2α-dependent metabolic and pathogenic endothelial activity. This lncRNA axis also increased HIF-2α expression across epigenetic, transcriptional, and posttranscriptional contexts, thus promoting a positive feedback loop to further augment HIF-2α activity. We identified a genetic association between rs73184087, a single-nucleotide variant (SNV) within a KMT2E intron, and disease risk in PAH discovery and replication patient cohorts and in a global meta-analysis. This SNV displayed allele (G)-specific association with HIF-2α, engaged in long-range chromatin interactions, and induced the lncRNA-KMT2E tandem in hypoxic (G/G) cells. In vivo, KMT2E-AS1 deficiency protected against PAH in mice, as did pharmacologic inhibition of histone methylation in rats. Conversely, forced lncRNA expression promoted more severe PH. Thus, the KMT2E-AS1/KMT2E pair orchestrates across convergent multi-ome landscapes to mediate HIF-2α pathobiology and represents a key clinical target in pulmonary hypertension.

AIMS: Pulmonary arterial hypertension (PAH) is a life-threatening condition. Although pulmonary vasodilators have shown promise in managing PAH, the improvement in prognosis is modest, partly because of a lack of biomarkers to guide their selection. Herein, we aimed to identify molecular-based predictors of responsiveness to pulmonary vasodilators using clinical and preclinical investigations. METHODS AND RESULTS: RNA sequencing was conducted on cultured pulmonary artery smooth muscle cells (PASMCs) from patients with and without pulmonary hypertension (PH), identifying variations in 3017 genes. Next, we performed a case-control study (PAH, n = 114; non-PH, n = 70) and examined plasma samples to identify potential clinical biomarkers. PASMCs exhibited elevated expression of C1q/TNF-related protein 7 (CTRP7; log2 fold change 5.37, P < 0.01). Patients with PAH had higher plasma CTRP7 levels [19.7 (9.8-90.5)] than those without PH [11.8 (0.6-61.6) ng/mL; P < 0.01]. Plasma and single-cell assessments revealed a significant correlation between CTRP7 and interleukin (IL)-6 levels (P < 0.001). Chromatin immunoprecipitation demonstrated that IL-6 up-regulated CTRP7 in PASMCs. CTRP7 reduced the expression of prostacyclin analogue receptor (PTGIR) through Rab5a-mediated internalization, resulting in diminished responsiveness to selexipag (prostacyclin analogue). Consistent with human study results, PTGIR expression was reduced in the pulmonary arteries of hypoxic PH mice, correlating with limited responses to selexipag treatment (low cardiac output and persistent pulmonary artery resistance); this effect was mitigated by the IL-6-R neutralizing antibody or adeno-associated virus-mediated silencing of CTRP7 expression in the pulmonary arteries. CONCLUSION: In patients with PAH, RNA sequencing of PASMCs revealed elevated expression of CTRP7 among candidate biomarkers. Patients with PAH had higher plasma CTRP7 levels than those without PH. Mechanistically, CTRP7 regulated PTGIR internalization via the IL-6-Rab5a axis, influencing responsiveness to selexipag. Herein, CTRP7 emerged as a crucial biomarker associating with responsiveness to prostacyclin analogues, advancing the development of PAH treatment strategies.

We herein report a 37-year-old man who experienced recurrence of metastatic cardiac rhabdomyosarcoma along with intractable ventricular tachycardia (VT) 7 years after resection of rhabdomyosarcoma in his right elbow. At 36 years old, he developed VT unresponsive to radiofrequency catheter ablation (RFCA). Initially, the cardiac tumor was not detected, but it gradually grew in size at the RFCA site. A surgical biopsy confirmed the diagnosis of metastatic cardiac rhabdomyosarcoma. Despite radiation therapy, cardiac tumor progression and VT instability could not be prevented. Ultimately, the patient died 27 months after the initial documentation of VT.

AIMS: The pathophysiology of pulmonary hypertension (PH) due to left-sided heart disease (Group 2 PH) is distinct from that of other groups of PH, yet there are still no approved therapies that selectively target pulmonary circulation. The increase in pulmonary capillary pressure due to left-sided heart disease is a trigger event for physical and biological alterations of the pulmonary circulation, including the nitric oxide (NO)-soluble guanylate cyclase-cyclic guanosine monophosphate axis. This study investigated inhaled NO vasoreactivity tests for patients with Group 2 PH and hypothesized that these changes may have a prognostic impact. METHODS AND RESULTS: This was a single-centre, retrospective study with a median follow-up of 365 days. From January 2011 to December 2015, we studied 69 patients with Group 2 PH [age, 61.5 ± 13.0 (standard deviation) years; male:female, 49:20; left ventricular ejection fraction, 50.1 ± 20.4%; mean pulmonary arterial pressure, ≥25 mmHg; and pulmonary arterial wedge pressure (PAWP), >15 mmHg]. No adverse events were observed after NO inhalation. Thirty-four patients with Group 2 PH showed increased PAWP (ΔPAWP: 3.26 ± 2.22 mmHg), while the remaining 35 patients did not (ΔPAWP: -2.11 ± 2.29 mmHg). Multivariate analysis revealed that increased PAWP was the only significant predictor of all-cause death or hospitalization for heart failure (HF) after 1 year (hazard ratio 4.35; 95% confidence interval, 1.27-14.83; P = 0.019). The acute response of PAWP to NO differed between HF with preserved and reduced ejection fractions. CONCLUSIONS: Patients with Group 2 PH were tolerant of the inhaled NO test. NO-induced PAWP is a novel prognostic indicator.

Chronic thromboembolic pulmonary hypertension (CTEPH), classified as group 4 pulmonary hypertension (PH), is caused by stenosis and obstruction of the pulmonary arteries by organized thrombi that are incompletely resolved after acute pulmonary embolism. The prognosis of patients with CTEPH is poor if untreated; however, in expert centers with multidisciplinary teams, a treatment strategy for CTEPH has been established, dramatically improving its prognosis. CTEPH is currently not a fatal disease and is the only curable form of PH. Despite these advances and the establishment of treatment approaches, early diagnosis is still challenging, especially for non-experts, for several reasons. One of the reasons for this is insufficient knowledge of the various diagnostic imaging modalities, which are essential in the clinical practice of CTEPH. Imaging modalities should detect the following pathological findings: lung perfusion defects, thromboembolic lesions in pulmonary arteries, and right ventricular remodeling and dysfunction. Perfusion lung scintigraphy and catheter angiography have long been considered gold standards for the detection of perfusion defects and assessment of vascular lesions, respectively. However, advances in imaging technology of computed tomography and magnetic resonance imaging have enabled the non-invasive detection of these abnormal findings in a single examination. Cardiac magnetic resonance (CMR) is the gold standard for evaluating the morphology and function of the right heart; however, state-of-the-art techniques in CMR allow the assessment of cardiac tissue characterization and hemodynamics in the pulmonary arteries. Comprehensive knowledge of the role of imaging in CTEPH enables appropriate use of imaging modalities and accurate image interpretation, resulting in early diagnosis, determination of treatment strategies, and appropriate evaluation of treatment efficacy. This review summarizes the current roles of imaging in the clinical practice for CTEPH, demonstrating the characteristic findings observed in each modality.

Cancer therapies are being considered for treating rare noncancerous diseases like pulmonary hypertension (PH), but effective computational screening is lacking. Via transcriptomic differential dependency analyses leveraging parallels between cancer and PH, we mapped a landscape of cancer drug functions dependent upon rewiring of PH gene clusters. Bromodomain and extra-terminal motif (BET) protein inhibitors were predicted to rely upon several gene clusters inclusive of galectin-8 (LGALS8). Correspondingly, LGALS8 was found to mediate the BET inhibitor–dependent control of endothelial apoptosis, an essential role for PH in vivo. Separately, a piperlongumine analog’s actions were predicted to depend upon the iron-sulfur biogenesis gene ISCU. Correspondingly, the analog was found to inhibit ISCU glutathionylation, rescuing oxidative metabolism, decreasing endothelial apoptosis, and improving PH. Thus, we identified crucial drug-gene axes central to endothelial dysfunction and therapeutic priorities for PH. These results establish a wide-ranging, network dependency platform to redefine cancer drugs for use in noncancerous conditions.

Background: Many patients with heart failure with preserved ejection fraction (HFpEF) have metabolic syndrome and develop exercise-induced pulmonary hypertension (EIPH). Increases in pulmonary vascular resistance in patients with HFpEF portend a poor prognosis; this phenotype is referred to as combined pre-and post-capillary PH (CpcPH). Therapeutic trials for EIPH and CpcPH have been disappointing, suggesting the need for strategies that target upstream mechanisms of disease. This work reports novel rat EIPH models and mechanisms of pulmonary vascular dysfunction centered around the transcriptional repression of the soluble guanylate cyclase (sGC) enzyme in pulmonary artery smooth muscle cells (PAVSMCs). Methods: We used obese ZSF-1 leptin-receptor knock-out rats (HFpEF model), obese ZSF-1 rats treated with SU5416 to stimulate resting PH (Obese+sugen, CpcPH model), and Lean ZSF-1 rats (controls). Right and left ventricular hemodynamics were evaluated via implanted-catheters during treadmill exercise. PA function was evaluated using MRI and myography. Overexpression of NFYA, a transcriptional-enhancer of sGCβ1, was performed by PA delivery of adeno-associated-virus 6 (AAV6). Treatment groups received SGLT2 inhibitor Empagliflozin in drinking water. PAVSMCs from rats and humans were cultured with Palmitic acid, Glucose, and Insulin (PGI) to induce metabolic-stress. Results: Obese rats showed normal resting right ventricular systolic pressures (RVSP) which significantly increased during exercise, modeling EIPH. Obese+sugen rats showed anatomical PA remodeling and developed elevated RVSP at rest, which was exacerbated with exercise, modeling CpcPH. Myography and MRI during dobutamine-challenge revealed PA functional impairment of both obese groups. PAs of obese rats produced reactive oxygen species (ROS) and decreased sGCβ1 expression. Mechanistically, cultured PAVSMCs from obese rats, humans with diabetes or treated with PGI, showed increased mitochondrial-ROS, which enhanced miR-193b-dependent RNA-degradation of NFYA, resulting in decreased sGCβ1-cGMP signaling. Forced NYFA expression by AAV6 delivery increased sGCβ1 levels and improved exercise-PH in Obese+sugen rats. Treatment of Obese+sugen rats with Empagliflozin improved metabolic syndrome, reduced mitochondrial ROS and miR-193b levels, restored NFYA/sGC activity, and prevented EIPH. Conclusions: In HFpEF and CpcPH models, metabolic syndrome contributes to pulmonary vascular dysfunction and EIPH through enhanced ROS and miR-193b expression, which down-regulates NFYA-dependent sGCβ1 expression. AAV-mediated NFYA overexpression and SGLT2 inhibition restores NFYA-sGCβ1-cGMP signaling and ameliorates EIPH.

The dynamic regulation of endothelial pathophenotypes in pulmonary hypertension (PH) remains undefined. Cellular senescence is linked to PH with intracardiac shunts; however, its regulation across PH subtypes is unknown. Since endothelial deficiency of iron-sulfur (Fe-S) clusters is pathogenic in PH, we hypothesized that a Fe-S biogenesis protein, frataxin (FXN), controls endothelial senescence. An endothelial subpopulation in rodent and patient lungs across PH subtypes exhibited reduced FXN and elevated senescence. In vitro, hypoxic and inflammatory FXN deficiency abrogated activity of endothelial Fe-S-containing polymerases, promoting replication stress, DNA damage response, and senescence. This was also observed in stem cell-derived endothelial cells from Friedreich's ataxia (FRDA), a genetic disease of FXN deficiency, ataxia, and cardiomyopathy, often with PH. In vivo, FXN deficiency-dependent senescence drove vessel inflammation, remodeling, and PH, whereas pharmacologic removal of senescent cells in Fxn-deficient rodents ameliorated PH. These data offer a model of endothelial biology in PH, where FXN deficiency generates a senescent endothelial subpopulation, promoting vascular inflammatory and proliferative signals in other cells to drive disease. These findings also establish an endothelial etiology for PH in FRDA and left heart disease and support therapeutic development of senolytic drugs, reversing effects of Fe-S deficiency across PH subtypes.

<h4>Objective</h4>Pulmonary arterial hypertension is characterized by abnormal proliferation of pulmonary artery smooth muscle cells and vascular remodeling, which leads to right ventricular (RV) failure. Bsg (Basigin) is a transmembrane glycoprotein that promotes myofibroblast differentiation, cell proliferation, and matrix metalloproteinase activation. CyPA (cyclophilin A) binds to its receptor Bsg and promotes pulmonary artery smooth muscle cell proliferation and inflammatory cell recruitment. We previously reported that Bsg promotes cardiac fibrosis and failure in the left ventricle in response to pressure-overload in mice. However, the roles of Bsg and CyPA in RV failure remain to be elucidated. Approach and Results: First, we found that protein levels of Bsg and CyPA were upregulated in the heart of hypoxia-induced pulmonary hypertension (PH) in mice and monocrotaline-induced PH in rats. Furthermore, cardiomyocyte-specific Bsg-overexpressing mice showed exacerbated RV hypertrophy, fibrosis, and dysfunction compared with their littermates under chronic hypoxia and pulmonary artery banding. Treatment with celastrol, which we identified as a suppressor of Bsg and CyPA by drug screening, decreased proliferation, reactive oxygen species, and inflammatory cytokines in pulmonary artery smooth muscle cells. Furthermore, celastrol treatment ameliorated RV systolic pressure, hypertrophy, fibrosis, and dysfunction in hypoxia-induced PH in mice and SU5416/hypoxia-induced PH in rats with reduced Bsg, CyPA, and inflammatory cytokines in the hearts and lungs.<h4>Conclusions</h4>These results indicate that elevated Bsg in pressure-overloaded RV exacerbates RV dysfunction and that celastrol ameliorates RV dysfunction in PH model animals by suppressing Bsg and its ligand CyPA. Thus, celastrol can be a novel drug for PH and RV failure that targets Bsg and CyPA. Graphic Abstract: A graphic abstract is available for this article.

Background Although chronic thromboembolic pulmonary hypertension (CTEPH) and acute pulmonary embolism (APE) share some clinical manifestations, a limited proportion of patients with CTEPH have a history of APE. Moreover, in histopathologic studies, it has been revealed that pulmonary vasculature lesions similar to pulmonary arterial hypertension existed in patients with CTEPH. Thus, it remains unknown whether these 3 disorders also share genetic backgrounds. Methods and Results Whole exome screening was performed with DNA isolated from 51 unrelated patients with CTEPH of Japanese ancestry. The frequency of genetic variants associated with pulmonary arterial hypertension or APE in patients with CTEPH was compared with those in the integrative Japanese Genome Variation Database 3.5KJPN. Whole exome screening analysis showed 17 049 nonsynonymous variants in patients with CTEPH. Although we found 6 nonsynonymous variants that are associated with APE in patients with CTEPH, there was no nonsynonymous variant associated with pulmonary arterial hypertension. Patients with CTEPH with a history of APE had nonsynonymous variants of F5, which encodes factor V. In contrast, patients with CTEPH without a history of APE had a nonsynonymous variant of THBD, which encodes thrombomodulin. Moreover, thrombin-activatable fibrinolysis inhibitor, which is one of the pathogenic proteins in CTEPH, was significantly more activated in those who had the variants of THBD compared with those without it. Conclusions These results provide the first evidence that patients with CTEPH have some variants associated with APE, regardless of the presence or absence of a history of APE. Furthermore, the variants might be different between patients with CTEPH with and without a history of APE.

<h4>Objective</h4>Pulmonary hypertension (PH) due to left heart disease (group 2), especially in the setting of heart failure with preserved ejection fraction (HFpEF), is the most common cause of PH worldwide; however, at present, there is no proven effective therapy available for its treatment. PH-HFpEF is associated with insulin resistance and features of metabolic syndrome. The stable prostacyclin analog, treprostinil, is an effective and widely used Food and Drug Administration-approved drug for the treatment of pulmonary arterial hypertension. While the effect of treprostinil on metabolic syndrome is unknown, a recent study suggests that the prostacyclin analog beraprost can improve glucose intolerance and insulin sensitivity. We sought to evaluate the effectiveness of treprostinil in the treatment of metabolic syndrome-associated PH-HFpEF. Approach and Results: Treprostinil treatment was given to mice with mild metabolic syndrome-associated PH-HFpEF induced by high-fat diet and to SU5416/obese ZSF1 rats, a model created by the treatment of rats with a more profound metabolic syndrome due to double leptin receptor defect (obese ZSF1) with a vascular endothelial growth factor receptor blocker SU5416. In high-fat diet-exposed mice, chronic treatment with treprostinil reduced hyperglycemia and pulmonary hypertension. In SU5416/Obese ZSF1 rats, treprostinil improved hyperglycemia with similar efficacy to that of metformin (a first-line drug for type 2 diabetes mellitus); the glucose-lowering effect of treprostinil was further potentiated by the combined treatment with metformin. Early treatment with treprostinil in SU5416/Obese ZSF1 rats lowered pulmonary pressures, and a late treatment with treprostinil together with metformin improved pulmonary artery acceleration time to ejection time ratio and tricuspid annular plane systolic excursion with AMPK (AMP-activated protein kinase) activation in skeletal muscle and the right ventricle.<h4>Conclusions</h4>Our data suggest a potential use of treprostinil as an early treatment for mild metabolic syndrome-associated PH-HFpEF and that combined treatment with treprostinil and metformin may improve hyperglycemia and cardiac function in a more severe disease.

Background Circulating proteins are exposed to vascular endothelial layer and influence their functions. Among them, adipsin is a member of the trypsin family of peptidases and is mainly secreted from adipocytes, monocytes, and macrophages, catalyzing the rate-limiting step of the alternative complement pathway. However, its pathophysiological role in cardiovascular disease remains to be elucidated. Here, we examined whether serum adipsin levels have a prognostic impact in patients with coronary artery disease. Methods and Results In 370 consecutive patients undergoing diagnostic coronary angiography, we performed a cytokine array analysis for screening serum levels of 50 cytokines/chemokines and growth factors. Among them, classification and regression analysis identified adipsin as the best biomarker for prediction of their long-term prognosis (median 71 months; interquartile range, 55-81 months). Kaplan-Meier curve showed that higher adipsin levels (≥400 ng/mL) were significantly associated with all-cause death (hazard ratio [HR], 4.2; 95% CI, 1.7-10.6 [P<0.001]) and rehospitalization (HR, 2.4; 95% CI, 1.7-3.5 [P<0.001]). Interestingly, higher high-sensitivity C-reactive protein levels (≥1 mg/L) were significantly correlated with all-cause death (HR, 3.2; 95% CI, 1.7-5.9 [P<0.001]) and rehospitalization (HR, 1.5, 95% CI, 1.1-1.9 [P<0.01]). Importantly, the combination of adipsin (≥400 ng/mL) and high-sensitivity C-reactive protein (≥1 mg/L) was more significantly associated with all-cause death (HR, 21.0; 95% CI, 2.9-154.1 [P<0.001]). Finally, the receiver operating characteristic curve demonstrated that serum adipsin levels predict the death caused by acute myocardial infarction in patients with coronary artery disease (C-statistic, 0.847). Conclusions These results indicate that adipsin is a novel biomarker that predicts all-cause death and rehospitalization in patients with coronary artery disease, demonstrating the novel aspects of the alternative complementary system in the pathogenesis of coronary artery disease.

<h4>Objective</h4>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.<h4>Conclusions</h4>Serum SeP is a novel biomarker for diagnosis and assessment of treatment efficacy and long-term prognosis in patients with PAH.

<h4>Background</h4>Although cardiac troponin and natriuretic peptide have been shown to decrease after balloon pulmonary angioplasty (BPA) with improved right ventricular afterload in chronic thromboembolic pulmonary hypertension (CTEPH), biomarkers to evaluate the effects of BPA independently of heart failure status remain to be developed.<h4>Methods</h4>In 39 consecutive CTEPH patients including 31 who underwent BPA, we measured plasma levels of cyclophilin A (CyPA), which we demonstrated is secreted from pulmonary vascular smooth muscle cells in response to mechanical stretch and hypoxia.<h4>Results</h4>CyPA levels were elevated in CTEPH patients (12.7, IQR: 7.6-16.0) compared with 8 thromboembolic controls with a history of venous thromboembolism (4.9, IQR: 2.4-11.2) or 18 healthy controls (4.1, IQR: 2.4-6.8) (both p< 0.05) and were linearly correlated with mean pulmonary arterial pressure (r=0.50, p = 0.0003) and pulmonary vascular resistance (r=0.32, p= 0.026). BPA reduced CyPA levels and tended to lower brain-type natriuretic peptide (BNP) levels (p< 0.01 and p = 0.07). When comparing the changes in CyPA before and after BPA in the two subgroups with higher (≥35pg/mL) and normal (<35pg/mL) BNP at baseline, CyPA decreased both in patients with higher BNP and those with normal BNP (both p< 0.05). In contrast, BNP decreased only in patients with higher BNP (p< 0.05). Also, CyPA decreased both in patients with lower (<25 kg/m²) and higher (≥25kg/m²) body mass index (BMI) at baseline (both p<0.05), whereas BPA tended to reduce BNP in patients with lower BMI (p = 0.12) but not in those with higher BMI (p = 0.55).<h4>Conclusions</h4>CyPA could be a useful biomarker to evaluate the effects of BPA even in patients with normal BNP or high BMI.

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.

<h4>Objective</h4>Excessive proliferation and apoptosis resistance are special characteristics of pulmonary artery smooth muscle cells (PASMCs) in pulmonary arterial hypertension (PAH). However, the drugs in clinical use for PAH target vascular dilatation, which do not exert adequate effects in patients with advanced PAH. Here, we report a novel therapeutic effect of emetine, a principal alkaloid extracted from the root of ipecac clinically used as an emetic and antiprotozoal drug. Approach and Results: We performed stepwise screenings for 5562 compounds from original library. First, we performed high-throughput screening with PASMCs from patients with PAH (PAH-PASMCs) and found 80 compounds that effectively inhibited proliferation. Second, we performed the repeatability and counter assay. Finally, we performed a concentration-dependent assay and found that emetine inhibits PAH-PASMC proliferation. Interestingly, emetine significantly reduced protein levels of HIFs (hypoxia-inducible factors; HIF-1α and HIF-2α) and downstream PDK1 (pyruvate dehydrogenase kinase 1). Moreover, emetine significantly reduced the protein levels of RhoA (Ras homolog gene family, member A), Rho-kinases (ROCK1 and ROCK2 [rho-associated coiled-coil containing protein kinases 1 and 2]), and their downstream CyPA (cyclophilin A), and Bsg (basigin) in PAH-PASMCs. Consistently, emetine treatment significantly reduced the secretion of cytokines/chemokines and growth factors from PAH-PASMCs. Interestingly, emetine reduced protein levels of BRD4 (bromodomain-containing protein 4) and downstream survivin, both of which are involved in many cellular functions, such as cell cycle, apoptosis, and inflammation. Finally, emetine treatment ameliorated pulmonary hypertension in 2 experimental rat models, accompanied by reduced inflammatory changes in the lungs and recovered right ventricular functions.<h4>Conclusions</h4>Emetine is an old but novel drug for PAH that reduces excessive proliferation of PAH-PASMCs and improves right ventricular functions.

<h4>Rationale</h4>Pulmonary arterial hypertension (PAH) is characterized by enhanced proliferation of pulmonary artery smooth muscle cells (PASMCs) accompanying increased production of inflammatory factors and adaptation of the mitochondrial metabolism to a hyperproliferative state. However, all the drugs in clinical use target pulmonary vascular dilatation, which may not be effective for patients with advanced PAH.<h4>Objective</h4>We aimed to discover a novel drug for PAH that inhibits PASMC proliferation.<h4>Methods and results</h4>We screened 5562 compounds from original library using high-throughput screening system to discover compounds which inhibit proliferation of PASMCs from patients with PAH (PAH-PASMCs). We found that celastramycin, a benzoyl pyrrole-type compound originally found in a bacteria extract, inhibited the proliferation of PAH-PASMCs in a dose-dependent manner with relatively small effects on PASMCs from healthy donors. Then, we made 25 analogs of celastramycin and selected the lead compound, which significantly inhibited cell proliferation of PAH-PASMCs and reduced cytosolic reactive oxygen species levels. Mechanistic analysis demonstrated that celastramycin reduced the protein levels of HIF-1α (hypoxia-inducible factor 1α), which impairs aerobic metabolism, and κB (nuclear factor-κB), which induces proinflammatory signals, in PAH-PASMCs, leading to reduced secretion of inflammatory cytokine. Importantly, celastramycin treatment reduced reactive oxygen species levels in PAH-PASMCs with increased protein levels of Nrf2 (nuclear factor erythroid 2-related factor 2), a master regulator of cellular response against oxidative stress. Furthermore, celastramycin treatment improved mitochondrial energy metabolism with recovered mitochondrial network formation in PAH-PASMCs. Moreover, these celastramycin-mediated effects were regulated by ZFC3H1 (zinc finger C3H1 domain-containing protein), a binding partner of celastramycin. Finally, celastramycin treatment ameliorated pulmonary hypertension in 3 experimental animal models, accompanied by reduced inflammatory changes in the lungs.<h4>Conclusions</h4>These results indicate that celastramycin ameliorates pulmonary hypertension, reducing excessive proliferation of PAH-PASMCs with less inflammation and reactive oxygen species levels, and recovered mitochondrial energy metabolism. Thus, celastramycin is a novel drug for PAH that targets antiproliferative effects on PAH-PASMCs.

<h4>Background</h4>Deficiencies of iron-sulfur (Fe-S) clusters, metal complexes that control redox state and mitochondrial metabolism, have been linked to pulmonary hypertension (PH), a deadly vascular disease with poorly defined molecular origins. BOLA3 (BolA Family Member 3) regulates Fe-S biogenesis, and mutations in BOLA3 result in multiple mitochondrial dysfunction syndrome, a fatal disorder associated with PH. The mechanistic role of BOLA3 in PH remains undefined.<h4>Methods</h4>In vitro assessment of BOLA3 regulation and gain- and loss-of-function assays were performed in human pulmonary artery endothelial cells using siRNA and lentiviral vectors expressing the mitochondrial isoform of BOLA3. Polymeric nanoparticle 7C1 was used for lung endothelium-specific delivery of BOLA3 siRNA oligonucleotides in mice. Overexpression of pulmonary vascular BOLA3 was performed by orotracheal transgene delivery of adeno-associated virus in mouse models of PH.<h4>Results</h4>In cultured hypoxic pulmonary artery endothelial cells, lung from human patients with Group 1 and 3 PH, and multiple rodent models of PH, endothelial BOLA3 expression was downregulated, which involved hypoxia inducible factor-2α-dependent transcriptional repression via histone deacetylase 1-mediated histone deacetylation. In vitro gain- and loss-of-function studies demonstrated that BOLA3 regulated Fe-S integrity, thus modulating lipoate-containing 2-oxoacid dehydrogenases with consequent control over glycolysis and mitochondrial respiration. In contexts of siRNA knockdown and naturally occurring human genetic mutation, cellular BOLA3 deficiency downregulated the glycine cleavage system protein H, thus bolstering intracellular glycine content. In the setting of these alterations of oxidative metabolism and glycine levels, BOLA3 deficiency increased endothelial proliferation, survival, and vasoconstriction while decreasing angiogenic potential. In vivo, pharmacological knockdown of endothelial BOLA3 and targeted overexpression of BOLA3 in mice demonstrated that BOLA3 deficiency promotes histological and hemodynamic manifestations of PH. Notably, the therapeutic effects of BOLA3 expression were reversed by exogenous glycine supplementation.<h4>Conclusions</h4>BOLA3 acts as a crucial lynchpin connecting Fe-S-dependent oxidative respiration and glycine homeostasis with endothelial metabolic reprogramming critical to PH pathogenesis. These results provide a molecular explanation for the clinical associations linking PH with hyperglycinemic syndromes and mitochondrial disorders. These findings also identify novel metabolic targets, including those involved in epigenetics, Fe-S biogenesis, and glycine biology, for diagnostic and therapeutic development.

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.

<h4>Background</h4>Thoracic aortic aneurysm (TAA) and dissection are fatal diseases that cause aortic rupture and sudden death. The small GTP-binding protein GDP dissociation stimulator (SmgGDS) is a crucial mediator of the pleiotropic effects of statins. Previous studies revealed that reduced force generation in aortic smooth muscle cells (AoSMCs) causes TAA and thoracic aortic dissection.<h4>Methods</h4>To examine the role of SmgGDS in TAA formation, we used an angiotensin II (1000 ng·min^-1·kg^-1, 4 weeks)-induced TAA model.<h4>Results</h4>We found that 33% of Apoe^-/- SmgGDS^+/- mice died suddenly as a result of TAA rupture, whereas there was no TAA rupture in Apoe^-/- control mice. In contrast, there was no significant difference in the ratio of abdominal aortic aneurysm rupture between the 2 genotypes. We performed ultrasound imaging every week to follow up the serial changes in aortic diameters. The diameter of the ascending aorta progressively increased in Apoe^-/- SmgGDS^+/- mice compared with Apoe^-/- mice, whereas that of the abdominal aorta remained comparable between the 2 genotypes. Histological analysis of Apoe^-/- SmgGDS^+/- mice showed dissections of major thoracic aorta in the early phase of angiotensin II infusion (day 3 to 5) and more severe elastin degradation compared with Apoe^-/- mice. Mechanistically, Apoe^-/- SmgGDS^+/- mice showed significantly higher levels of oxidative stress, matrix metalloproteinases, and inflammatory cell migration in the ascending aorta compared with Apoe^-/- mice. For mechanistic analyses, we primary cultured AoSMCs from the 2 genotypes. After angiotensin II (100 nmol/L) treatment for 24 hours, Apoe^-/- SmgGDS^+/- AoSMCs showed significantly increased matrix metalloproteinase activity and oxidative stress levels compared with Apoe^-/- AoSMCs. In addition, SmgGDS deficiency increased cytokines/chemokines and growth factors in AoSMCs. Moreover, expressions of fibrillin-1 ( FBN1), α-smooth muscle actin ( ACTA2), myosin-11 ( MYH11), MYLLK, and PRKG1, which are force generation genes, were significantly reduced in Apoe^-/- SmgGDS^+/- AoSMCs compared with Apoe^-/- AoSMCs. A similar tendency was noted in AoSMCs from patients with TAA compared with those from control subjects. Finally, local delivery of the SmgGDS gene construct reversed the dilation of the ascending aorta in Apoe^-/- SmgGDS^+/- mice.<h4>Conclusions</h4>These results suggest that SmgGDS is a novel therapeutic target for the prevention and treatment of TAA.

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.

Although postcapillary pulmonary hypertension (PH) is an important prognostic factor for patients with heart failure (HF), its pathogenesis remains to be fully elucidated. To elucidate the different roles of Rho-kinase isoforms, ROCK1 and ROCK2, in cardiomyocytes in response to chronic pressure overload, we performed transverse aortic constriction (TAC) in cardiac-specific ROCK1-deficient (cROCK1^-/-) and ROCK2-deficient (cROCK2^-/-) mice. Cardiomyocyte-specific ROCK1 deficiency promoted pressure-overload-induced cardiac dysfunction and postcapillary PH, whereas cardiomyocyte-specific ROCK2 deficiency showed opposite results. Histological analysis showed that pressure-overload-induced cardiac hypertrophy and fibrosis were enhanced in cROCK1^-/- mice compared with controls, whereas cardiac hypertrophy was attenuated in cROCK2^-/- mice after TAC. Consistently, the levels of oxidative stress were up-regulated in cROCK1^-/- hearts and down-regulated in cROCK2^-/- hearts compared with controls after TAC. Furthermore, cyclophilin A (CyPA) and basigin (Bsg), both of which augment oxidative stress, enhanced cardiac dysfunction and postcapillary PH in cROCK1^-/- mice, whereas their expressions were significantly lower in cROCK2^-/- mice. In clinical studies, plasma levels of CyPA were significantly increased in HF patients and were higher in patients with postcapillary PH compared with those without it. Finally, high-throughput screening demonstrated that celastrol, an antioxidant and antiinflammatory agent, reduced the expressions of CyPA and Bsg in the heart and the lung, ameliorating cardiac dysfunction and postcapillary PH induced by TAC. Thus, by differentially affecting CyPA and Bsg expressions, ROCK1 protects and ROCK2 jeopardizes the heart from pressure-overload HF with postcapillary PH, for which celastrol may be a promising agent.

慢性血栓塞栓性肺高血圧症(CTEPH)患者の血栓が線溶系に抵抗性を示し、その線溶抵抗性にThrombin Activatable Fibrinolysis Inhibitor(TAFI)が関与しているか否かを検討した。右心カテーテル検査を行ったCTEPH患者27例、非肺高血圧症患者22例、肺動脈性肺高血圧症患者19例を対象とした。その結果、肺動脈性肺高血圧症患者や非肺高血圧症患者に比べて、CTEPH患者では血栓が線溶系に抵抗性を示すこと、血漿中TAFI抗原量が多く、経皮的肺動脈形成術により肺循環が改善した後も高値であったこと、血小板は活性化しやすく、血小板から放出されるTAFIの抗原量が多いこと、tPAに対する抵抗性はTAFIa阻害薬だけでなくPGE1でも改善することが示された。また、全身TAFI過剰発現マウスでは肺動脈内血栓の線溶が抑制されることがわかった。今回、CTEPH患者の血栓では全線溶能の低下を認め、TAFIがCTEPH患者の線溶系への抵抗性に関与していることが示された。

<h4>Rationale</h4>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.<h4>Objective</h4>To determine the role of activated TAFI (TAFIa) in the development of CTEPH.<h4>Methods and results</h4>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.<h4>Conclusions</h4>These results indicate that TAFIa could be a novel biomarker and realistic therapeutic target of CTEPH.

<h4>Objective</h4>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.<h4>Approach and results</h4>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.<h4>Conclusions</h4>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.

<h4>Rationale</h4>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.<h4>Objective</h4>To determine the role of endothelial AMPK in the development of PAH.<h4>Methods and results</h4>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.<h4>Conclusions</h4>These results indicate that endothelial AMPK is a novel therapeutic target for the treatment of PAH.

<h4>Objective</h4>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.<h4>Approach and results</h4>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.<h4>Conclusions</h4>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.

OBJECTIVE: Basigin (Bsg) is a transmembrane glycoprotein that activates matrix metalloproteinases and promotes inflammation. However, the role of Bsg in the pathogenesis of cardiac hypertrophy and failure remains to be elucidated. We examined the role of Bsg in cardiac hypertrophy and failure in mice and humans. APPROACH AND RESULTS: We performed transverse aortic constriction in Bsg(+/-) and in wild-type mice. Bsg(+/-) mice showed significantly less heart and lung weight and cardiac interstitial fibrosis compared with littermate controls after transverse aortic constriction. Both matrix metalloproteinase activities and oxidative stress in loaded left ventricle were significantly less in Bsg(+/-) mice compared with controls. Echocardiography showed that Bsg(+/-) mice showed less hypertrophy, less left ventricular dilatation, and preserved left ventricular fractional shortening compared with littermate controls after transverse aortic constriction. Consistently, Bsg(+/-) mice showed a significantly improved long-term survival after transverse aortic constriction compared with Bsg(+/+) mice, regardless of the source of bone marrow (Bsg(+/+) or Bsg(+/-)). Conversely, cardiac-specific Bsg-overexpressing mice showed significantly poor survival compared with littermate controls. Next, we isolated cardiac fibroblasts and examined their responses to angiotensin II or mechanical stretch. Both stimuli significantly increased Bsg expression, cytokines/chemokines secretion, and extracellular signal-regulated kinase/Akt/JNK activities in Bsg(+/+) cardiac fibroblasts, all of which were significantly less in Bsg(+/-) cardiac fibroblasts. Consistently, extracellular and intracellular Bsg significantly promoted cardiac fibroblast proliferation. Finally, serum levels of Bsg were significantly elevated in patients with heart failure and predicted poor prognosis. CONCLUSIONS: These results indicate the crucial roles of intracellular and extracellular Bsg in the pathogenesis of cardiac hypertrophy, fibrosis, and failure in mice and humans.

The detailed molecular mechanisms of the pleiotropic effects of statins remain to be fully elucidated. Here, we hypothesized that cardioprotective effects of statins are mediated by small GTP-binding protein GDP dissociation stimulator (SmgGDS). SmgGDS(+/-) and wild-type (WT) mice were treated with continuous infusion of angiotensin II (Ang II) for 2 weeks with and without oral treatment with atorvastatin or pravastatin. At 2 weeks, the extents of Ang II-induced cardiac hypertrophy and fibrosis were comparable between the 2 genotypes. However, statins significantly attenuated cardiomyocyte hypertrophy and fibrosis in WT mice, but not in SmgGDS(+/-) mice. In SmgGDS(+/-) cardiac fibroblasts (CFs), Rac1 expression, extracellular signal-regulated kinases 1/2 activity, Rho-kinase activity, and inflammatory cytokines secretion in response to Ang II were significantly increased when compared with WT CFs. Atorvastatin significantly reduced Rac1 expression and oxidative stress in WT CFs, but not in SmgGDS(+/-) CFs. Furthermore, Bio-plex analysis revealed significant upregulations of inflammatory cytokines/chemokines and growth factors in SmgGDS(+/-) CFs when compared with WT CFs. Importantly, conditioned medium from SmgGDS(+/-) CFs increased B-type natriuretic peptide expression in rat cardiomyocytes to a greater extent than that from WT CFs. Furthermore, atorvastatin significantly increased SmgGDS secretion from mouse CFs. Finally, treatment with recombinant SmgGDS significantly reduced Rac1 expression in SmgGDS(+/-) CFs. These results indicate that both intracellular and extracellular SmgGDS play crucial roles in the inhibitory effects of statins on cardiac hypertrophy and fibrosis, partly through inhibition of Rac1, Rho kinase, and extracellular signal-regulated kinase 1/2 pathways, demonstrating the novel mechanism of the pleiotropic effects of statins.

An 80-year-old Japanese man, who had fever and generalized fatigue not improved by antibiotics, was admitted to our hospital. Laboratory data indicative of renal dysfunction and antineutrophil cytoplasmic antibody (ANCA) in the serum led to the consideration of ANCA-associated vasculitis as a differential diagnosis. However, before the diagnostic confirmation, he was found dead on the bed. Autopsy revealed necrotizing crescentic glomerulonephritis in the kidneys. In addition, necrotizing granulomatous vasculitis with infiltration of multinucleated giant cells and neutrophils but not eosinophils was present in multiple organs. The direct cause of death was presumed as cardiac arrest by lethal arrhythmia because vasculitic lesions were distributed widely in the cardiac walls, acute congestion was observed in the systemic organs, and other causes of death were ruled out. This report presents the unusual manifestation of cardiac small-vessel involvement in ANCA-associated vasculitis related to sudden death.

<h4>Background</h4>Cardiopulmonary arrest in pregnancy has a very high maternal and fetal mortality rate. We report a case of successful maternal and neonatal survival in association with emergency cesarean section of a schizophrenic pregnant patient. To our knowledge, this is the first reported case of cardiopulmonary arrest in a pregnant woman with schizophrenia.<h4>Case presentation</h4>The parents were Japanese. The mother was 39 years old and had no history of prior pregnancy. Her admission to our hospital at 36 weeks and 4 days of pregnancy was due to deterioration of schizophrenia. On the first day of hospitalization, she collapsed after a seizure and vomiting, and an emergency resuscitation team was called immediately. The team identified apparent aspiration and successfully resuscitated the patient after 11 minutes of cardiopulmonary arrest. An emergency cesarean section was performed in the operating room. The newborn male infant received bag and mask ventilation at birth, and his Apgar scores were 5 at 1 minute and 8 at 5 minutes. He had a myoclonic seizure on the 2nd day of life: however, he experienced no further seizures on anticonvulsant medication after that episode. On the 18th day of life, magnetic resonance imaging of his brain revealed bilateral small hyperintensities on T1-weighted images in the basal ganglia. The mother and her newborn were discharged from our hospital without neurological disorders.<h4>Conclusion</h4>We speculate that the cause of cardiopulmonary arrest was aspiration due to seizure, and it is possible that a neurological response was evoked by administration of antipsychotic drugs and/or by eclampsia. Medical staff must be aware of the possibility of cardiopulmonary arrest in pregnant women with schizophrenia.

<h4>Rationale</h4>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.<h4>Objective</h4>To determine the role of CyPA/Bsg signaling in the development of PH.<h4>Methods and results</h4>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.<h4>Conclusions</h4>These results indicate the crucial role of extracellular CyPA and vascular Bsg in the pathogenesis of PH.