Sleep-disordered breathing and nocturnal hypoxemia in chronic thromboembolic pulmonary disease

BACKGROUND AND AIMS

Sleep-disordered breathing (SDB) and nocturnal hypoxemia were known to be present in patients with chronic thromboembolic pulmonary hypertension (CTEPH), but the difference between SDB and nocturnal hypoxemia in patients who have chronic thromboembolic pulmonary disease (CTEPD) with or without pulmonary hypertension (PH) at rest remains unknown.

METHODS

Patients who had CTEPH (n = 80) or CTEPD without PH (n = 40) and who had undergone sleep studies from July 2020 to October 2022 at Shanghai Pulmonary Hospital were enrolled. Nocturnal mean SpO2 (Mean SpO2) <90% was defined as nocturnal hypoxemia, and the percentage of time with a saturation below 90% (T90%) exceeding 10% was used to evaluate the severity of nocturnal hypoxemia. Logistic and linear regression analyses were performed to investigate the difference and potential predictor of SDB or nocturnal hypoxemia between CTEPH and CTEPD without PH.

RESULTS

SDB was similarly prevalent in CTEPH and CTEPD without PH (P = 0.104), both characterised by obstructive sleep apnoea (OSA). Twenty-two patients with CTEPH were diagnosed with nocturnal hypoxemia, whereas only three were diagnosed with CTEPD without PH (P = 0.021). T90% was positively associated with mean pulmonary arterial pressure (mPAP) and pulmonary vascular resistance in patients with CTEPH and CTEPD without PH (P < 0.001); T90% was also negatively related to cardiac output in these patients. Single-breath carbon monoxide diffusing capacity, sex and mPAP were all correlated with nocturnal hypoxemia in CTEPH and CTEPD without PH (all P < 0.05).

CONCLUSION

Nocturnal hypoxemia was worse in CTEPD with PH; T90%, but not SDB, was independently correlated with the hemodynamics in CTEPD with or without PH.

Identification of the shared gene signatures between pulmonary fibrosis and pulmonary hypertension using bioinformatics analysis

Pulmonary fibrosis (PF) and pulmonary hypertension (PH) have common pathophysiological features, such as the significant remodeling of pulmonary parenchyma and vascular wall. There is no effective specific drug in clinical treatment for these two diseases, resulting in a worse prognosis and higher mortality. This study aimed to screen the common key genes and immune characteristics of PF and PH by means of bioinformatics to find new common therapeutic targets. Expression profiles are downloaded from the Gene Expression Database. Weighted gene co-expression network analysis is used to identify the co-expression modules related to PF and PH. We used the ClueGO software to enrich and analyze the common genes in PF and PH and obtained the protein-protein interaction (PPI) network. Then, the differential genes were screened out in another cohort of PF and PH, and the shared genes were crossed. Finally, RT-PCR verification and immune infiltration analysis were performed on the intersection genes. In the result, the positive correlation module with the highest correlation between PF and PH was determined, and it was found that lymphocyte activation is a common feature of the pathophysiology of PF and PH. Eight common characteristic genes (ACTR2, COL5A2, COL6A3, CYSLTR1, IGF1, RSPO3, SCARNA17 and SEL1L) were gained. Immune infiltration showed that compared with the control group, resting CD4 memory T cells were upregulated in PF and PH. Combining the results of crossing characteristic genes in ImmPort database and RT-PCR, the important gene IGF1 was obtained. Knocking down IGF1 could significantly reduce the proliferation and apoptosis resistance in pulmonary microvascular endothelial cells, pulmonary smooth muscle cells, and fibroblasts induced by hypoxia, platelet-derived growth factor-BB (PDGF-BB), and transforming growth factor-β1 (TGF-β1), respectively. Our work identified the common biomarkers of PF and PH and provided a new candidate gene for the potential therapeutic targets of PF and PH in the future.

Single-Cell Transcriptome Analysis of Peripheral Neutrophils From Patients With Idiopathic Pulmonary Arterial Hypertension

BACKGROUND

Idiopathic pulmonary hypertension (IPAH) is a rare and devastating disease often accompanied by persistent inflammation and immune responses. We aim to provide a reference atlas of neutrophils to facilitate a better understanding of cellular phenotypes and discovery of candidate genes.

METHODS

Peripheral neutrophils from naive patients with IPAH and matched controls were profiled. Whole-exon sequencing was performed to exclude known genetic mutations before establishing single-cell RNA sequencing. Marker genes were validated by flow cytometry and histology in a separate validation cohort.

RESULTS

Seurat clustering analysis revealed that the landscape of neutrophils encompassed 5 clusters, including 1 progenitor, 1 transition, and 3 functional clusters. The intercorrelated genes in patients with IPAH were mainly enriched in antigen processing presentation and natural killer cell mediated cytotoxicity. We identified and validated differentially upregulated genes, including matrix metallopeptidase 9 (MMP9), ISG15 ubiquitin-like modifier (ISG15), and C-X-C motif ligand 8 (CXCL8). The positive proportions and fluorescence quantification of these genes were significantly increased in CD16⁺ neutrophils in patients with IPAH. The higher proportion of positive MMP9 (matrix metallopeptidase 9) neutrophils increased mortality risk after adjustment for age and sex. Patients with higher proportions of positive MMP9 neutrophils had worse survival, while the fraction of ISG15- or C-X-C motif chemokine ligand 8-positive expression neutrophils failed to predict outcome.

CONCLUSIONS

Our study yields a comprehensive dataset of the landscape of neutrophils in patients with IPAH. The predictive values of a neutrophil cluster characterized by higher MMP9 expression indicate a functional role for neutrophil-specific matrix metalloproteinases in the pathogenesis of pulmonary arterial hypertension.

Development of a model to investigate the effects of prolonged ischaemia on the muscles of mastication of male Sprague Dawley rats

OBJECTIVE

The aims of this study were to develop a novel rodent model of masticatory muscle ischaemia via unilateral ligation of the external carotid artery (ECA), and to undertake a preliminary investigation to characterize its downstream effects on mechanosensitivity and cellular features of the masseter and temporalis muscles.

DESIGN

The right ECA of 18 male Sprague-Dawley rats was ligated under general anaesthesia. Mechanical detection thresholds (MDTs) at the masseter and temporalis bilaterally were measured immediately before ECA ligation and after euthanasia at 10-, 20-, and 35-days (n = 6 rats/timepoint). Tissue samples from both muscles and sides were harvested for histological analyses and for assessing changes in the expression of markers of hypoxia and muscle degeneration (Hif-1α, VegfA, and Fbxo32) via real time PCR. Data were analyzed using mixed effect models and non-parametric tests. Statistical significance was set at p < 0.05.

RESULTS

MDTs were higher in the right than left hemiface (p = 0.009) after 20 days. Histological changes indicative of muscle degeneration and fibrosis were observed in the right muscles. Hif-1α, VegfA, and Fbxo32 were more highly expressed in the masseter than temporalis muscles (all p < 0.05). Hif-1α and, VegfA did not change significantly with time in all muscles (all p > 0.05). Fbxo32 expression gradually increased in the right masseter (p = 0.024) and left temporalis (p = 0.05).

CONCLUSIONS

ECA ligation in rats induced hyposensitivity in the homolateral hemiface after 20 days accompanied by tissue degenerative changes. Our findings support the use of this model to study pathophysiologic mechanisms of masticatory muscle ischaemia in larger investigations.

Differences in disease severity and prognosis of exercise-induced right-to-left shunt between idiopathic pulmonary arterial hypertension and chronic thromboembolic pulmonary hypertension patients

Objective

Whether exercise-induced venous-to-systemic shunt (EIS) during cardiopulmonary exercise testing (CPET) has different manifestations or characteristics in idiopathic pulmonary arterial hypertension (IPAH) and chronic thromboembolic pulmonary hypertension (CTEPH) patients remains unknown. We explored the differences in hemodynamics, echocardiography, and prognosis between IPAH and CTEPH patients with and without EIS.

Methods

We conducted a retrospective cross-sectional cohort study and included 161 PH patients at Shanghai Pulmonary Hospital. Demographic, echocardiography, pulmonary hemodynamic, and CPET variables were compared between patients with and without EIS stratified by IPAH and CTEPH. EIS was determined by CPET. Binary logistic regression analyses were performed to explore independent influencing factors of EIS. Cox survival analysis was used to quantify the impact of EIS on the prognosis of patients.

Results

Exercise-induced venous-to-systemic shunt was found in approximately 17.4% of 86 IPAH patients and 20% of 75 CTEPH patients. All-cause mortality occurred in 43 (26.7%) patients during a median follow-up of 6.5 years. Compared with those without EIS, patients with EIS had higher peak end-tidal O₂ and lower VO₂/VE and tricuspid annular plane systolic excursion (TAPSE). Among the IPAH patients, EIS was associated with lower cardiac output, cardiac index, mixed venous oxygen saturation, VO₂/VE, and TAPSE and higher VE/VCO₂ and right ventricular end-diastolic transverse diameter. Logistic regression analysis indicated that VO₂/VE was an independent factor influencing whether IPAH patients developed EIS during CPET. Cox logistic regression indicated that female IPAH patients or IPAH patients with higher VO₂/VE and EIS had a better prognosis. Female IPAH patients had better 10-year survival. In IPAH patients without EIS, patients with higher VO₂/VE had better 10-year survival. However, compared with CTEPH patients without EIS, those with EIS had similar echocardiographic, hemodynamic, CPET parameter results and 10-year survival.

Conclusion

Exercise-induced venous-to-systemic shunt exhibits different profiles among IPAH and CTEPH patients. Among IPAH patients, those with EIS had worse peak end-tidal O₂, VO₂/VE, and TAPSE than those without EIS. VO₂/VE was an independent factor of EIS among IPAH patients. IPAH patients with EIS, female sex or higher VO₂/VE had better survival. However, the association between EIS and PAH severity or prognosis in CTEPH patients needs to be further explored.

Efficacy and safety of switching from bosentan or ambrisentan to macitentan in pulmonary arterial hypertension: A systematic review and meta-analysis

Background

There is little evidence of the effectiveness of switching from the endothelin receptor antagonists (ERAs) bosentan and ambrisentan to a novel ERA, macitentan, in patients with pulmonary arterial hypertension (PAH). Therefore, a systematic review and meta-analysis was performed to evaluate the efficacy and safety of patients with PAH switching from other ERAs to macitentan.

Methods

We retrieved the relevant literature published before January 2022 for the meta-analysis from the PubMed, EMBASE, and Cochrane Library databases. Efficacy included changes in the 6-min walk distance (6MWD), World Health Organization functional class (WHO-FC), N-terminal pro-brain natriuretic peptide (NT-proBNP) levels, hemodynamics, echocardiography and survival.

Results

Nine studies, consisting of 408 PAH patients, that met the inclusion criteria were included. The switch from bosentan or ambrisentan to macitentan effectively increased the 6MWD by 20.71 m (95% CI: 10.35-31.07, P < 0.00001, I ² = 0%). Six months after conversion, the tricuspid annular plane systolic excursion was found to improve from 19.0 ± 4.0 to 21.0 ± 5.0 mm in adults and from 16.00 ± 5.0 to 18.25 ± 4.8 mm in children. Ordinal logistic regression showed that the WHO-FC significantly improved by 0.412 (95% CI: 0.187-0.908, P = 0.028). The switch did not show significant improvement in NT-proBNP levels. In addition, the switch was well tolerated.

Conclusion

The switch from bosentan or ambrisentan to macitentan significantly increased the 6MWD in PAH patients, improved the WHO-FC, and exerted safety benefits. The effects of the switch on NT-proBNP levels, hemodynamics, and echocardiography still need to be further confirmed.

Systematic review registration

[https://www.crd.york.ac.uk/prospero/], identifier [CRD42021292554].

Long-term outcomes in health-related quality of life influence chronic disease management in patients with pulmonary hypertension

Background

Significantly improved survival in patients with pulmonary hypertension (PH) has raised interest in maintaining a good quality of long-term survivorship. In this study, health-related quality of life (HRQOL) measurement was used to assess the long-term changes of physical and mental outcomes.

Methods

A total of 559 consecutive inpatients with PH completed generic HRQOL (Short Form-36) who were diagnosed with PH by right heart catheterization. Assessments were carried out at short-term (1 year), midterm (3 years), and long-term (5 years) follow-ups.

Results

Patients with PH suffered more severe impairments in both physical and emotional domains than the U.S. population normative values. Patients with PH due to chronic lung disease had the worst physical component summary (PCS) score, but there was no difference in mental component summary (MCS) score among different PH types. A reduced PCS score was correlated with WHO FC severity and pulmonary vascular resistance (PVR). The Z score showed that the changing trend of mental conditions continuously declined from baseline to midterm and long-term follow-ups, but the PCS score seemed to be stable or improved. Cox regression analysis indicated increased baseline PVR and WHO FC III and IV, and decreased physical subscale of role physical, mental subscale of social functioning, and the MCS score have increased risk of mortality in the long-term follow-up.

Conclusion

Patients with PH have poor HRQOL. The long-term change of physical status seemed to be stable, but the mental state was continuously worse. These suggested identifying and intervening mental health progresses is a noteworthy issue in PH chronic management.

Sex-specific differences in sleep-disordered breathing and nocturnal hypoxemia in chronic thromboembolic pulmonary hypertension and chronic thromboembolic pulmonary disease

Objective

Although chronic thromboembolic pulmonary hypertension (CTEPH) and chronic thromboembolic pulmonary disease (CTEPD) are known to be accompanied by symptoms associated with sleep-disordered breathing (SDB) and nocturnal hypoxemia, the sex-specific differences of SDB and nocturnal hypoxemia in patients with CTEPH and CTEPD remain unknown.

Methods

Between July 2020 and August 2022, data were retrieved from 57 males and 63 female patients with CTEPH and CTEPD who underwent sleep study at Shanghai Pulmonary Hospital. Nocturnal mean SpO₂ (mean SpO₂) < 90% was defined as nocturnal hypoxemia. Logistic and linear regression analysis was performed to assess the predictive value of sleep study indices to hemodynamic parameters. Receiver operating characteristic (ROC) curve was applied to analyze the specific parameters to predict the risk of CTEPH.

Results

SDB was similarly present in males and females, and both sexes predominantly had obstructive sleep apnea (OSA); more women were diagnosed with nocturnal hypoxemia (32 vs. 7%, p = 0.002). SaO₂ was negatively associated with mean pulmonary arterial pressure (mPAP) in men (p < 0.001), whereas the ratio of nocturnal SpO₂ < 90% of the total monitoring time (T90%) was positively correlated with mPAP. Mean SpO₂ was an independent predictor for pulmonary vascular resistance and cardiac output in women (p = 0.001, p < 0.001, p = 0.001, respectively). T90%, SaO₂, and minimal SpO₂ were combined to develop a new composite parameter: hypoxemia scoring index (HSI). ROC curve analysis indicated that HSI levels of 0.55 could discriminate CTEPH from CTEPD with a sensitivity of 92.3% and specificity of 87.5% in female patients (an area under the curve, 0.937; 95% CI: 0.879–0.995, p < 0.001).

Conclusion

Sex-specific nocturnal hypoxemia was present in patients with CTEPH or CTEPD. In female patients, the HSI showed high capacity for predicting the risk of CTEPH.

Clinical trials registration

Registry: chictr.org.cn; Identifier: ChiCTR-DDD-16009406.

A Study of the Efficacy and Safety of Aerobic Exercise Training in Pulmonary Arterial Hypertension (the Saturday Study): Protocol for a Prospective, Randomized, and Controlled Trial

Background

Patients with pulmonary arterial hypertension (PAH) have reduced exercise capacity and poor quality of life. Exercise-based rehabilitation in PAH results in clinically relevant improvements in exercise capacity and hemodynamics. To clarify the mechanism, we will evaluate the effect of aerobic exercise training rehabilitation on right ventricular (RV) remodeling and function as determined measured by cardiac magnetic resonance imaging (CMR).

Methods

We will conduct a 26-week multicenter randomized controlled trial. Patients on stable and unchanged PAH-targeted medication are randomly assigned (1:1) to the control and training groups. The primary endpoint is the RV stroke volume (RVSV) change from baseline to Week 26, determined by CMR. Comprehensive RV function is also performed using CMR. Other characteristics of the RV and left ventricle, World Health Organization functional class, 6-min walk distance, and N-terminal pro-B-type natriuretic peptide are included in secondary endpoints. We also investigate the proteomic, metabolomic, and transcriptomic changes after exercise training as exploratory endpoints.

Ethics and Dissemination

The study and protocol were approved by the Ethics Committee of Shanghai Pulmonary Hospital (Approved No. of ethics committee: L20-17). The results will be disseminated at medical conferences and in journal publications. All participants will sign written informed consent.

Trial Registration Number

ChiCTR2000031650.

Peak oxygen uptake is a strong prognostic predictor for pulmonary hypertension due to left heart disease

Background

Pulmonary hypertension in left heart disease (PH-LHD), which includes combined post- and precapillary PH (Cpc-PH) and isolated postcapillary PH (Ipc-PH), differs significantly in prognosis. We aimed to assess whether cardiopulmonary exercise testing (CPET) predicts the long-term survival of patients with PH-LHD.

Methods

A single-center observational cohort enrolled 89 patients with PH-LHD who had undergone right heart catherization and CPET (mean pulmonary arterial pressure > 20 mm Hg and pulmonary artery wedge pressure ≥ 15 mm Hg) between 2013 and 2021. A receiver operating characteristic curve was plotted to determine the cutoff value of all-cause death. Survival was estimated using the Kaplan–Meier method and analyzed using the log-rank test. The Cox proportional hazards model was performed to determine the association between CPET and all-cause death.

Results

Seventeen patients died within a mean of 2.2 ± 1.3 years. Compared with survivors, nonsurvivors displayed a significantly worse 6-min walk distance, workload, exercise time and peak oxygen consumption (VO₂)/kg with a trend of a lower oxygen uptake efficiency slope (OUES) adjusted by Bonferroni’s correction. Multivariate Cox regression revealed that the peak VO₂/kg was significantly associated with all-cause death after adjusting for Cpc-PH/Ipc-PH. Compared with Cpc-PH patients with a peak VO₂/kg ≥ 10.7 ml kg⁻¹ min⁻¹, Ipc-PH patients with a peak VO₂/kg < 10.7 ml kg⁻¹ min⁻¹ had a worse survival (P < 0.001).

Conclusions

The peak VO₂/kg is independently associated with all-cause death in patients with PH-LHD. The peak VO₂/kg can also be analyzed together with Cpc-PH/Ipc-PH to better indicate the prognosis of patients with PH-LHD.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12872-022-02574-0.

Echocardiography Nomogram for Predicting Survival among Chronic Lung Disease Patients with Severe Pulmonary Hypertension

Severe pulmonary hypertension in chronic lung diseases (severe CLD-PH) differs significantly from other types of PH in physiology and prognosis. We aimed to assess whether echocardiography helps predict long-term survival in patients with severe CLD-PH. This single-centre, observational cohort study enrolled 100 patients with severe CLD-PH (mean pulmonary arterial pressure ≥35 mm Hg or ≥25 mm Hg with cardiac index <2.0 L/min/m2 or pulmonary vascular resistance ≥6 Wood units) between 2009 and 2014. The population was randomly divided into a derivation and validation cohort in a 2:1 ratio. To construct a nomogram, a multivariable logistic regression model was applied, and scores were assigned based on the hazard ratio of independent echocardiographic predictors. Multivariate Cox hazards analysis identified the strongest predictors of mortality as pulmonary arterial systolic pressure (PASP), tricuspid annular plane systolic excursion, and right ventricular end-diastolic transverse dimension. The three independent predictors were entered into the nomogram. Compared with PASP alone, the nomogram resulted in an integrated discrimination improvement of 15.5% (95% confidence interval, 5.52−25.5%, p = 0.002) with a net improvement in model discrimination (C-statistic from 0.591 to 0.746). Using echocardiographic parameters, we established and validated a novel nomogram to predict all-cause death for patients with severe CLD-PH.

The Role of Glutamine and Glutaminase in Pulmonary Hypertension

Pulmonary hypertension (PH) refers to a clinical and pathophysiological syndrome in which pulmonary vascular resistance and pulmonary arterial pressure are increased due to structural or functional changes in pulmonary vasculature caused by a variety of etiologies and different pathogenic mechanisms. It is followed by the development of right heart failure and even death. In recent years, most studies have found that PH and cancer shared a complex common pathological metabolic disturbance, such as the shift from oxidative phosphorylation to glycolysis. During the shifting process, there is an upregulation of glutamine decomposition driven by glutaminase. However, the relationship between PH and glutamine hydrolysis, especially by glutaminase is yet unclear. This review aims to explore the special linking among glutamine hydrolysis, glutaminase and PH, so as to provide theoretical basis for clinical precision treatment in PH.

Balloon pulmonary angioplasty combined with riociguat for the treatment of inoperable chronic thromboembolic pulmonary hypertension (PRACTICE study): study protocol for a randomized controlled trial

Background

Management of inoperable chronic thromboembolic pulmonary hypertension (CTEPH) remains a clinical challenge. Currently, riociguat, a soluble guanylate-cyclase stimulator is recommended by international guidelines. More recently, balloon pulmonary angioplasty (BPA) develops as an alternative treatment for inoperable CTEPH.

Method

This study is a single-center randomized controlled trial. Subjects with inoperable CTEPH are randomized into either a BPA combined with riociguat or riociguat monotherapy group (2:1) and observed for 12 months after initiation of treatment. The primary endpoint is the change in pulmonary vascular resistance from baseline to 12 months after initiation of treatment. The secondary endpoints include 6-min walk distance (6MWD), WHO-FC, NT-proBNP, SF-36, and other hemodynamic parameters. Safety endpoints are analyzed too.

Discussion

This study aims to compare the efficacy and safety of BPA combined with riociguat and riociguat monotherapy for inoperable CTEPH.

Trial registration

Chinese Clinical Trial Registry ChiCTR2000032403. Registered on 27 April 2020.

Validity of the ESC Risk Assessment in Idiopathic Pulmonary Arterial Hypertension in China

Background: The 2015 European pulmonary hypertension (PH) guidelines recommend a risk stratification strategy for pulmonary arterial hypertension (PAH). We aimed to investigate the validation and potential prognostic information in Chinese patients. Methods: The risk assessment variables proposed by the PH guidelines were performed by using the WHO function class, 6-min walking distance, brain natriuretic peptide or its N-terminal fragment, right arterial pressure, cardiac index, mixed venous saturation, right atrium area, pericardial effusion, peak oxygen consumption, and ventilatory equivalents for carbon dioxide. An abbreviated version also was applied. Results: A total of 392 patients with idiopathic PAH (IPAH) were enrolled between 2009 and 2018. After a median interval of 13 months, re-evaluation assessments were available for 386 subjects. The PAH guidelines risk tool may effectively discriminate three risk groups and mortality (p < 0.001) both at the baseline and re-evaluation. Meanwhile, its simplified risk version was valid for baseline and accurately predicted the risk of death in all the risk groups (p < 0.001). At the time of re-evaluation, the percentage of low-risk group has an increase, but a greater proportion achieved the high-risk group and a lesser proportion maintained in the intermediate-risk group. Conclusion: The 2015 European PH guidelines and its simplified version risk stratification assessment present an effective discrimination of different risk groups and accurate mortality estimates in Chinese patients with IPAH. Changes of risk proportion at re-evaluation implicated that natural treatment decisions may not be consistently with goal-oriented treatment strategy.

PeakPETCO2 combined with FEV1/FVC predicts vasodilator-responsive patients with idiopathic pulmonary arterial hypertension

Cardiopulmonary exercise testing and pulmonary function test are important methods for detecting human cardio-pulmonary function. Whether they could screen vasoresponsiveness in idiopathic pulmonary artery hypertension (IPAH) patients remains undefined. One hundred thirty-two IPAH patients with complete data were retrospectively enrolled. Patients were classified as vasodilator-responsive (VR) group and vasodilator-nonresponsive (VNR) group on the basis of the acute vasodilator test. Pulmonary function test and cardiopulmonary exercise testing were assessed subsequently and all patients were confirmed by right heart catheterization. We analyzed cardiopulmonary exercise testing and pulmonary function test data and derived a prediction rule to screen vasodilator-responsive patients in IPAH. Nineteen of VR-IPAH and 113 of VNR-IPAH patients were retrospectively enrolled. Compared with VNR-IPAH patients, VR-IPAH patients had less severe hemodynamic effects (lower RAP, m PAP, PAWP, and PVR). And VR-IPAH patients had higher anaerobic threshold (AT), peak partial pressure of end-tidal carbon dioxide (PETCO2), oxygen uptake efficiency (OUEP), and FEV1/FVC (P all <0.05), while lower peak partial pressure of end-tidal oxygen (PETO2) and minute ventilation (VE)/carbon dioxide output (VCO2) slope (P all <0.05). FEV1/FVC (Odds Ratio [OR]: 1.14, 95% confidence interval [CI]: 1.02-1.26, P = 0.02) and PeakPETCO2 (OR: 1.13, 95% CI: 1.01-1.26, P = 0.04) were independent predictors of VR adjusted for age, sex, and body mass index. A novel formula (=-16.17 + 0.123 × PeakPETCO2 + 0.127×FEV1/FVC) reached a high area under the curve value of 0.8 (P = 0.003). Combined with these parameters, the optimal cutoff value of this model for detection of VR is -1.06, with a specificity of 91% and sensitivity of 67%. Compared with VNR-IPAH patients, VR-IPAH patients had less severe hemodynamic effects. Higher FEV1/FVC and higher peak PETCO2 were associated with increased odds for vasoresponsiveness. A novel score combining PeakPETCO2 and FEV1/FVC provides high specificity to predict VR patients among IPAH.

Effectiveness and safety of exercise training and rehabilitation in chronic thromboembolic pulmonary hypertension: a systematic review and meta-analysis

BACKGROUND

Patients with chronic thromboembolic pulmonary hypertension (CTEPH) still have impaired exercise training and quality of life (QoL) despite pulmonary arterial hypertension (PAH)-targeted drugs. Exercise training is considered to improve exercise capacity and QoL in patients with pulmonary hypertension (PH), but this has not been fully studied in CTEPH patients. We conducted the meta-analysis and systematic review to evaluate the effectiveness and safety of exercise training in patients with CTEPH.

METHODS

The relevant literature was retrieved for the meta-analysis using the PubMed, EMBASE, and Cochrane Library databases published before December 2020. The primary outcome was a change in six-minute walk distance (6MWD). We also assessed the effect of exercise training on peak oxygen uptake per kilogram (peak VO2/kg), mean pulmonary artery pressure (mPAP) assessed by right heart catheterization (RHC), N-terminal pro-brain-type natriuretic peptide (NT-proBNP), and QoL.

RESULTS

A total of 6 studies with 234 exercise training patients were included. In the pooled analysis, 6MWD significantly improved by 70.14 m (WMD: 58.33 to 81.95, I2=0) after 3-week exercise training. After 12 or 15-week exercise training, 6MWD and peak VO2/kg significantly improved (WMD: 106.22 m, 95% CI: 65.90 to 146.55, I2=87.4%, P<0.0001; 1.84 mL/min/kg, 95% CI: 0.72 to 2.96, P=0.001, respectively). Furthermore, the mPAP decreased by 12.17 mmHg after 12-week exercise training (95% CI: -14.53 to -9.82, P<0.001, I2=99%). The subscales of QoL such as physical function, general health perception, and mental health improved in varying degrees. NT-proBNP did not improve significantly in the pooled analysis. In addition, exercise training was well tolerated without major adverse events occurred during training, and the dropout rate was low.

DISCUSSION

Exercise training may improve exercise capacity, mPAP, and QoL, and was well tolerated among patients with CTEPH. However, more large-scale multicenter studies are needed to confirm the effectiveness and safety of exercise training in patients with CTEPH.

Epidemiology of Takayasu arteritis in Shanghai: A hospital-based study and systematic review

BACKGROUND

Takayasu arteritis (TAK) is a rare large vessel vasculitis, and epidemiological data on TAK are lacking in China. Thus, we designed this study to estimate the TAK prevalence and incidence in residential Shanghai, China.

METHODS

Data on diagnosed TAK cases aged over 16 years were retrieved from 22 tertiary hospitals in Shanghai through hospital electronic medical record systems between January 1, 2015 and December 31, 2017 to estimate the prevalence and incidence. A systematic literature review based on searches in PubMed, Ovid-Medline, Excerpta Medica Database (EMBASE), Web of Science, and China National Knowledge Infrastructure (CNKI) was performed to summarize TAK distribution across the world.

RESULTS

In total 102 TAK patients, with 64% female, were identified. The point prevalence (2015-2017) was 7.01 (95% CI 5.65-8.37) cases per million, and the mean annual incidence was 2.33 (1.97-3.21) cases per million. The average age of TAK patients was 44 ± 16 years, with the highest prevalence (11.59 [9.23-19.50] cases per million) and incidence (3.55 [0.72 3.74] cases per million) in the 16 to 34 years population. Seventeen reports were included in the system review, showing that the epidemiology of TAK varied greatly across the world. The incidence and prevalence were both relatively higher in Asian countries, with the prevalence ranging 3.3-40 cases per million and annual incidence ranging 0.34-2.4 cases per million.

CONCLUSIONS

The prevalence and incidence of TAK in Shanghai was at moderate to high levels among the previous reports. The disease burden varied globally among racial populations.

Survival in severe pulmonary hypertension due to chronic lung disease: influence of in-hospital platelet distribution width

Platelet distribution width has been recognized as risk predictors of idiopathic pulmonary arterial hypertension. This study aims to investigate whether in-hospital platelet distribution width would be useful to predict all-cause death in patients with severe pulmonary hypertension due to chronic lung diseases (CLD-PH). Early in-hospital platelet distribution width was measured in 67 severe CLD-PH patients who were confirmed by right heart catheterization and followed up. Event-free survival was estimated using the Kaplan–Meier method and analyzed with the log-rank test. Cox proportional hazards models were performed to determine the association between the platelet distribution width level and all-cause death. During median of 2.4 (2.5, 3.7) years of follow-up, 44 patients died. A significant association was noted between in-hospital platelet distribution width level and the adjusted risk of all-cause mortality (hazard ratio: 1.245; 95% confidence interval: 1.117–1.386, P < 0.001). Compared with those with platelet distribution width <16.1%, the hazard ratio for all-cause death increased by 5.278 (95% confidence interval: 2.711–10.276, P < 0.0001) among patients with platelet distribution width ≥16.1%. Higher levels of platelet distribution width were also associated with increased risk of all-cause death. In-hospital platelet distribution width was independently associated with all-cause death in patients with severe CLD-PH. This potentially could be used to estimate the severity of severe CLD-PH.

Comparative Effectiveness of Exercise Training for Patients With Chronic Thromboembolic Pulmonary Hypertension After Pulmonary Endarterectomy: A Systematic Review and Meta-Analysis

Background: Patients with chronic thromboembolic pulmonary hypertension (CTEPH) still experience reduced exercise capacity despite pulmonary endarterectomy (PEA). Exercise training improves the exercise capacity and quality of life (QoL) in patients with PH, but data on the effects of exercise training on these patients are scarce. The aim of this meta-analysis and systematic review was to evaluate the effectiveness and safety of exercise training in CTEPH after PEA.

Methods: We searched the relevant literature published before January 2020 for the systematic review and meta-analysis using the PubMed, EMBASE, and Cochrane Library databases. The primary outcome was a change in the 6-min walking distance (6 MWD). We also assessed the effect of exercise on the peak oxygen uptake (VO₂) or peak VO₂/kg, oxygen uptake anaerobic threshold, workload, oxygen pulse, hemodynamics, arterial blood gases, oxygen saturation, N-terminal pro-brain-type natriuretic peptide (NT-proBNP), quality of life (QoL) and pulmonary function tests.

Results: We included 4 studies with 208 exercise-training participants. In the pooled analysis, short-term exercise training can improve the 6 MWD of 58.89 m (95% CI: 46.26–71.52 m, P < 0.0001). There was a significant increase in the peak VO₂/kg or peak VO₂ after exercise training (3.15 ml/min/kg, 95% CI: 0.82–5.48, P = 0.008; 292.69 ml/min, 95% CI: 24.62–560.75, P = 0.032, respectively). After exercise training, the maximal workload and O₂ pulse significantly improved. Three months of exercise training increased the right ventricular ejection fraction by 3.53% (95% CI: 6.31–11.94, P < 0.00001, I² = 0) independently of PEA surgery. In addition, NT-proBNP plasma levels significantly improved with exercise training after PEA [weighted mean difference (WMD): −524.79 ng/L, 95% CI: 705.16 to −344.42, P < 0.0001, I² = 0]. The partial pressure of oxygen and pH improved progressively over 12 weeks of exercise training (WMD: 4 mmHg, 95% CI: 1.01–8.33, P = 0.01; WMD: 0.03, 95% CI: 0.02–0.04, P < 0.0001, respectively). Subscales of the QoL measured by the SF-36 questionnaire had also improved. In addition, exercise training was well-tolerated with a low dropout rate, and no major adverse events occurred during exercise training.

Conclusion: Exercise training may be associated with a significant improvement in the exercise capacity and QoL among CTEPH patients after PEA and was proven to be safe. However, more large-scale multicentre studies are needed to confirm the effectiveness and safety of exercise training in CTEPH patients after PEA.

PROSPERO registration number:CRD42021235275.

Echocardiographic Prognosis Relevance of Attenuated Right Heart Remodeling in Idiopathic Pulmonary Arterial Hypertension

Background: Right ventricular (RV) function is a great determination of the fate in patients with pulmonary arterial hypertension (PAH). Monitoring RV structure back to normal or improvement should be useful for evaluation of RV function. The aims of this study were to assess the prognostic relevance of changed right heart (RH) dimensions by echocardiography and attenuated RH remodeling (ARHR) in idiopathic PAH (IPAH).

Methods: We retrospectively analyzed 232 consecutive adult IPAH patients at baseline assessment and included RH catheterization and echocardiography. ARHR at the mean 20 ± 12 months' follow-up was defined by a decreased right atrium area, RV mid-diameter, and left ventricular end-diastolic eccentricity index. The follow-up end point was all-cause mortality.

Results: At mean 20 ± 12 months' follow-up, 33 of 232 patients (14.2%) presented with ARHR. The remaining 199 surviving patients were monitored for another 25 ± 20 months. At the end of follow-up, the survival rates at 1, 3, and 5 years were 89, 89, and 68% in patients with ARHR, respectively, and 84, 65 and 41% in patients without ARHR (log-rank p = 0.01). ARHR was an independent prognostic factor for mortality. Besides, ARHR was available to further stratify patients' risk assessment through the French PAH non-invasive-risk criteria.

Conclusions: Echocardiographic ARHR is an independent determinant of prognosis in IPAH at long-term follow-up. ARHR might be a useful tool to indicate the RV morphologic and functional improvement associated with better prognostic likelihood.

Plasma exosomal miR-596: a novel biomarker predicts survival in patients with idiopathic pulmonary artery hypertension

Objective

To determine if plasma exosomal microRNAs (miRNAs) can predict survival in patients with idiopathic pulmonary arterial hypertension (IPAH).

Methods

The study enrolled patients with IPAH that underwent right heart catheterization. Plasma was collected and exosomal miRNAs were extracted. Exosomes were evaluated using transmission electron microscopy, Western blot analysis and particle size distribution analysis. MiRNAs were evaluated using a miRNA microarray and validated using real-time polymerase chain reaction.

Results

This study included 12 patients with IPAH in the study group and 48 patients with IPAH in the validation group. The mean ± SD follow-up duration was 60.3 ± 35.4 months in the overall cohort. The levels of miR-596 were higher in the nonsurvivors compared with the survivors. The levels of miR-596 significantly correlated with survival time, mean right atrial pressure, pulmonary vascular resistance (PVR) and cardiac index. High levels of miR-596 and PVR were significantly associated with poor overall survival. Multivariate analysis demonstrated that exosomal miR-596 (hazard ratio [HR] = 2.119; 95% confidence interval [CI] 1.402, 3.203) and PVR (HR = 1.146; 95% CI 1.010, 1.300) were independent predictors of survival.

Conclusions

High levels of plasma exosomal miR-596 were significantly associated with disease severity and poor prognosis of patients with IPAH.

Alteration of Extracellular Superoxide Dismutase in Idiopathic Pulmonary Arterial Hypertension

Background: Superoxide dismutases (SODs) are an important family of antioxidant enzymes that modulate reactive oxygen species levels. It is largely unknown which SOD isoform(s) change in vivo in idiopathic pulmonary arterial hypertension (IPAH) patients.

Methods: A total of 133 consecutive adult IPAH patients who underwent bone morphogenetic protein receptor type 2 (BMPR2) genetic counseling were enrolled in this prospective study. The plasma activities of three subtypes of SOD [copper–zinc (Cu/Zn-SOD), manganese (Mn-SOD), and extracellular SOD (Ec-SOD)] were examined.

Results: The activities of SODs were significantly lower in IPAH patients than in healthy subjects. However, only Ec-SOD activity in BMPR2 mutation patients was significantly decreased compared to those in patients without a mutation. The reduced Ec-SOD activity was markedly associated with mean pulmonary arterial pressure, pulmonary vascular resistance (PVR), and 6-min walking distance (6MWD). The reduction of Mn-SOD activity was only associated with 6MWD. There was no association between Cu/Zn-SOD and hemodynamics. Patients with a lower Ec-SOD level had a worse survival compared to those with a higher baseline. The reduced Ec-SOD activity and the raised PVR increased the mortality risk.

Conclusions: Ec-SOD was correlated with BMPR2 mutation, hemodynamic dysfunction, and poor outcomes. Circulating Ec-SOD could be a potentially vital antioxidant enzyme in the pathogenesis of IPAH.

Prognostic Value of Gamma-Glutamyltransferase in Male Patients With Idiopathic Pulmonary Arterial Hypertension

Background: The elevated gamma-glutamyltransferase (GGT) activity is regarded as an indicator of cardiovascular disease, with males having higher values than females. The greater incidence of idiopathic pulmonary arterial hypertension (IPAH) is observed in women, whereas prognosis is poor in men. The present study aims to investigate the potential association of GGT on male patients.

Methods: Serum GGT levels were measured in 338 consecutive adult IPAH patients, who underwent bone morphogenetic protein receptor type 2 (BMPR2) genetic counseling, and matched with healthy subjects by sex and age. The followed interval was 48 ± 34 months.

Results: Increased serum GGT levels were more common in patients with IPAH than controls (p < 0.001). GGT values were significantly higher in male patients than those of females (p < 0.001). Compared with female patients with BMPR2 mutation, GGT level in male patients with BMPR2 mutation was further increased (p = 0.002). Higher GGT levels were associated with worse hemodynamics and Nterminal pro B-type natriuretic peptide in all patients. However, males with a GGT concentration ≥ 53 U/L had a worse survival than those of females. Contrarily, if GGT concentration <53 U/L, there was no survival difference between male and female patients. After adjustment for relevant variables of clinical features and hemodynamics, baseline higher GGT levels remained increased risks of all-cause mortality in males rather than females. During rehospitalization follow-up, male patients still had significantly higher values of GGT than females.

Conclusions: Increased GGT levels were correlated with BMPR2 mutation, hemodynamic dysfunction, and poor outcomes in male patients with IPAH. Further studies are needed to explain the origin of abnormal GGT and its potential pathogenesis in men.

Changed hemodynamics in acute vasoreactivity testing: prognostic predictors in chronic thromboembolic pulmonary hypertension

Chronic thromboembolic pulmonary hypertension (CTEPH) is similar to pulmonary arterial hypertension (PAH) in its pathogenesis. Changed hemodynamic parameters in acute vasoreactivity testing (AVT) have proved to be prognostic predictors of PAH. We wanted to determine whether these changed indices also impacted the prognosis of CTEPH. Data was retrieved for 86 CTEPH patients who underwent right heart catheterization (RHC) with AVT at Shanghai Pulmonary Hospital from 2009 to 2018 and following up for 20 ± 15 months for event. Cox proportional hazards models were performed to determine the predictors of independent event-free survival. Receiver operating characteristic curve was plotted to determine the cut-off value of independent parameters in CTEPH. Kaplan-Meier method and log-rank test were used to perform the Survival analyses. Forty seven patients had an event. Many hemodynamic indices improved after AVT. The event-free group had better mean right atrial pressure, mean pulmonary arterial pressure, pulmonary vascular resistance (PVR) and oxygen saturation of mixed venous blood (SvO2) both at baseline and after AVT. The event-free group also showed higher cardiac output (CO) and cardiac index (CI) after AVT. Among the changed hemodynamic parameters during the AVT, ΔCO, ΔCO/baseline CO, ΔCI, ΔCI/baseline CI and ΔPVR/baseline PVR were significantly higher in the event-free group. Foremost, ΔPVR/baseline PVR, PVR after AVT and baseline SvO2 were independent predictors for event-free survival. Patients with SvO2 ≥ 61.65% at baseline or PVR < 8.09 WU after AVT or ΔPVR/baseline PVR ≥ 0.054 had significantly better survival. Hemodynamic indices both at baseline and after AVT as well as the changes in these indices reflected the severity of CTEPH. Baseline SvO2, PVR after AVT, and ΔPVR/baseline PVR could be used as independent predictors to estimate the outcomes of CTEPH patients.

Variable predictors of acute pulmonary embolism recurrence with duration of follow-up

Background

Acute pulmonary embolism (PE) is a critical disease and often leads to a high mortality and morbidity. Several studies have identified predictors of PE recurrence, but whether these predictors have prognostic value and how they vary during varied follow-up periods remain unclear.

Methods

We retrospectively assessed the occurrence of recurrent PE and the survival time of patients with a diagnosis of acute PE at Shanghai Pulmonary Hospital from May 2007 to May 2018. Potential predictors of recurrent PE were evaluated at different points (1, 3, 6, 12, 24, 60 and 120-month) during a long-term follow-up for each patient. Patients were stratified into two groups by gender to analyze the impact of sex in period-guided prognostic prediction. Receiver operating characteristic curve analysis, survival analysis and multivariate Cox proportional hazards analysis were implemented as statistical analysis methods.

Results

In total, 597 acute PE patients were included, of whom 62 reported a PE recurrence. Male patients tend to have a lower risk of PE recurrence than female patients during 3- to 60-month follow-up period but have a higher risk of PE recurrence than female patients during 120-month follow-up period. The independent predictors of recurrence-free survival varied among different follow-up periods: In all patients, diabetes was an independent predictor only within 30 days follow-up period and female was considered as an independent predictor during 3- to 120-month follow-up period. Among male patients, hyperlipidemia and Log D-dimer (cut-off value =3.436) was observed as a predictor of recurrent PE within 6-month and over 12-month follow-up respectively. However, there is no unified independent prognostic indicator for female patients identified.

Conclusions

In the early stage of follow-up, male PE patients have better prognosis, but with the extension of follow-up, female PE patients have better prognosis. The independent predictors of recurrence-free survival vary in different follow-up periods in PE patients when stratified based on gender and associated medical conditions.

Sex differences of hemodynamics during acute vasoreactivity testing to predict the outcomes of chronic thromboembolic pulmonary hypertension

BACKGROUND

Acute vasoreactivity testing (AVT) which reflects the compliance of the pulmonary vascular bed has been proven to be of prognostic value. The purpose of the present study is to explore the sex differences of hemodynamics during the AVT and their impact on event-free survival in patients with chronic thromboembolic pulmonary hypertension (CTEPH).

METHODS

Eighty-six patients underwent a right heart catheterization and AVT at Shanghai Pulmonary Hospital from February 2009 to February 2018. Univariate and multiple stepwise regression analysis were performed to determine the predictors of independent event-free survival, and receiver operating characteristic curve was plotted to determine the cut-off value of independent parameters in CTEPH.

RESULTS

There were no significant differences in both demographics and hemodynamics between male and female patients with CTEPH. Except ΔPVR/PVR showed a significantly higher difference in female than male patients (P = 0.034). Male patients had higher mRAP of pre- and post-AVT than female patients in the event-free subgroup, while, female patients showed higher PVR of pre-AVT than male patients in the event subgroup (P < 0.05). The mRAP and SvO₂ were independent predictors of event-free survival in female patients both before and after the AVT, whereas ΔSvO₂ was an independent predictor of event-free survival in male patients.

CONCLUSION

Hemodynamics during the AVT varied between male and female patients with CTEPH. Both sexes displayed unique hemodynamic responses that were independently able to predict event-free survival. Therefore, better estimates of prognosis in CTEPH can be made when sex differences are also taken into consideration.

Value of heart rate recovery in female patients with pulmonary arterial hypertension due to systemic lupus erythematosus

OBJECTIVE

This study intended to explore the relation between heart rate recovery at 1 minutes (HRR1) during the recovery phase of cardiopulmonary exercise test (CPET) and exercise capacity in female systemic lupus erythematosus associated pulmonary arterial hypertension (SLE-PAH) patients.

METHODS

Twenty-one female SLE-PAH patients underwent right heart catheterization (RHC), pulmonary function test (PFT) and CPET. Forty-two healthy subjects matched with SLE-PAH patients in age, sex and BMI were recruited as a control group. The correlations between HRR1 with clinical and CPET parameters were performed.

RESULTS

Peak HR, ΔHR, HRR1, Peak HR-warm HR_1min , Peak HR-warm HR_2min and CR were significantly lower in SLE-PAH than in controls (P < .01). Increased incidence of CRI was seen in SLE-PAH. Except for the Peak P_ET O₂ , which was higher in controls, all other CPET parameters were lower in SLE-PAH. SLE-PAH patients with HRR1 ≥ 16 had longer 6MWD, lower NT-proBNP, better percent of predicted gas transfer index or diffusing capacity for carbon monoxide (DLco% pred) as well as better CO and CI. Peak HR, ΔHR, HRR1, Peak HR-warm HR_1min , Peak HR-warm HR_2min , CR, Peak Load, Peak VO₂ , Peak P_ET CO₂ , OUEP and OUES were lower and duration of exercise was shorter in patients with HRR1 < 16. HRR1 had positive correlation with 6MWD, DLco% pred, CO, CI and some key CPET parameters.

CONCLUSIONS

HRR1 is an easily obtained auxiliary parameter in SLE-PAH patients to reflect an altered autonomic tone. SLE-PAH patients with HRR1 < 16 have more severe hemodynamics, worse clinical findings and marked oxygen uptake inefficiency than those with HRR1 ≥ 16.

Characteristics of cardiopulmonary exercise testing of patients with borderline mean pulmonary artery pressure

BACKGROUND

Pulmonary hypertension patients with mean pulmonary artery pressure (mPAP) ≥ 25 mm Hg had impaired cardiopulmonary exercise testing (CPET). Borderline mean pulmonary pressures (boPAP; 21-24 mm Hg) represent early pulmonary vasculopathy. The CPET characteristics of boPAP are a matter of discussion. We aimed to determine the CPET profile of such borderline hemodynamics.

METHODS

A matched case-control study was conducted on consecutive boPAP patients at the Shanghai Pulmonary Hospital between Jan 2012 and Jan 2017. Hemodynamics, echocardiography, the pulmonary function test (PFT) and CPET parameters were compared between boPAP patients and normal mPAP patients which were matched 1:1 by sex and age. Conditional logistic regression analysis was performed to determine the efficacy of CPET in detecting boPAP.

RESULTS

A total of 48 patients underwent RHC and CPET (24 Normal, 24 boPAP). There were no differences in the demographics, echocardiography and PFT. BoPAP patients had significantly decreased VO₂ at the anaerobic threshold and peak VO₂ /kg (858.4 ± 246.5 mL/min vs 727.9 ± 228.0 mL/min, P = 0.037; 21.1 ± 6.4 mL/min/kg vs. 15.5 ± 5.6 mL/min/kg, P = 0.001, respectively). Significant differences were not observed in ventilation efficiency. A trend of impaired oxygen pulse and submaximal exercise tolerance were observed in boPAP patients. Conditional logistical regression analysis revealed the risk of boPAP increased by 2.493 (95% confident interval: 1.388 to 4.476, P = 0.002) with every 5 mL/min/kg decrease in peak VO₂ /kg.

CONCLUSIONS

Patients with boPAP have a greater prevalence of exercise intolerance, a trend of impaired oxygen pulse and submaximal exercise tolerance.

[Peripheral small airway dysfunction differences between idiopathic pulmonary arterial hypertension and chronic thromboembolic pulmonary hypertension]

Objective: To investigate the peripheral small airway dysfunction differences between idiopathic pulmonary arterial hypertension (IPAH) and chronic thromboembolic pulmonary hypertension (CTEPH). Methods: Impulse oscillmetory system testing (IOS) and pulmonary function testing (PFT) were performed in IPAH and CTEPH patients and 30 healthy control group. We also carried out a subgroup analysis depending on their medical history of airway diseases. Results: We included 42 IPAH and 47 CTEPH patients (with or without airways disease: 8 vs. 34 and 17 vs. 34, respectively). Compared with CTEPH patients, IPAH patients were younger but had more serious pulmonary vessel resistance and mean pulmonary arterial resistance. Compared with IPAH patients, CTEPH patients had significant impaired peripheral small airway dysfunction with decreased of MEF(50) (% pred), MMEF(75/25) evaluated by PFT and R5-R20, Δ R5-R20 and AX measured by IOS [10.6(2.0, 33.0) vs. 2.5(-5.0, 16.5); 22.1(14.0, 32.6) vs. 15.5 (7.0, 23.2); 7.64(4, 18.6) vs. 6(3, 11) respectively, all P<0.05]. Subgroup analysis revealed there were no significant peripheral small dysfunction differences in IPAH patients with or without airway diseases. CTEPH patients had a higher proportion of airway diseases and more serious peripheral dysfunction than IPAH patients with airway diseases. Compared with control healthy group, peripheral airway dysfunction was more obvious even in IPAH and CTEPH patients without airway diseases. Conclusion: Compared with IPAH, CTEPH patients were older, but had better hemodynamics and a higher proportion of airway diseases. The peripheral airway dysfunction were more serious in CTEPH patients without airway diseases than IPAH patients without airway diseases and healthy controls group.

Characteristics of exercise capacity in female systemic lupus erythematosus associated pulmonary arterial hypertension patients

BACKGROUND

To study the oxygen uptake efficiency and determine usefulness of submaximal parameters of oxygen uptake in systemic lupus erythematosus associated pulmonary arterial hypertension (SLE PAH) on performing a cardiopulmonary exercise test (CPET).

METHODS

CPET was performed in 21 SLE PAH patients, equal number of idiopathic pulmonary arterial hypertension (IPAH) patients and controls. Peak VO2, anaerobic threshold (AT), oxygen uptake efficiency slope (OUES) and oxygen uptake efficiency plateau (OUEP) and other CPET parameters were examined. All subjects had pulmonary function test (PFT) at rest, which included FEV1, FVC, FEV1/FVC, DLCO measurements. Right heart catheterization (RHC) was also done in SLE PAH and IPAH patients. CPET parameters were compared with RHC parameters to determine potential correlations.

RESULTS

Peak VO2, PETCO2 and peak O2 pulse were lower in SLE PAH than IPAH and controls with OUE being lower during all stages of exercise in SLE PAH. DLCO and FVC values were significantly lower in SLE PAH (p < 0.05). Peak O2 pulse and VO2@AT in SLE PAH and IPAH was low (p < 0.05) and significant difference between SLE PAH and IPAH was seen (p < 0.05). PVR correlated with the lowest VE/VCO2, O2 pulse, peak PETCO2 and OUE in SLE PAH patients (all p < 0.05).

CONCLUSIONS

SLE PAH patients have cardiopulmonary exercise limitation with reduced oxygen uptake efficiency. VO2@ at AT, peak O2 pulse and O2 pulse at AT were significantly reduced (p < 0.05). Key CPET parameters correlated with elevated pulmonary vascular resistance (PVR). Submaximal parameters of oxygen uptake are equally useful in SLE PAH.

Sex-specific cardiopulmonary exercise testing indices to estimate the severity of inoperable chronic thromboembolic pulmonary hypertension

Background

Sex differences in chronic thromboembolic pulmonary hypertension (CTEPH) have been revealed in few studies. Although right heart catheterization (RHC) is the gold standard for clinical diagnosis and assessment of prognosis in pulmonary hypertension (PH), cardiopulmonary exercise testing (CPET) has been a more widely used assessment of functional capacity, disease severity, prognosis, and treatment response in PH. We hypothesized that the “sex-specific” CPET indices could estimate the severity of inoperable CTEPH.

Methods

Data were retrieved for 33 male (age, mean ± standard deviation [SD] =62.5±13.4 years) and 40 female (age, mean ± SD =56.3±11.8 years) patients with stable CTEPH who underwent both RHC and CPET at Shanghai Pulmonary Hospital from February 2010 to February 2016. Univariate and forward/backward multiple stepwise regression analysis was performed to assess the predictive value of CPET indices to hemodynamic parameters. Event-free survival was estimated using the Kaplan–Meier method and analyzed with the log-rank test. Cox proportional hazards models were performed to determine the independent event-free survival predictors.

Results

Numerous CPET parameters were different between male and female patients with CTEPH and the control group. There were no significant differences in both clinical variables and RHC parameters between male and female patients with CTEPH. O₂ pulse, workload, minute ventilation (VE), and end-tidal partial pressure of O₂ (P_ETO₂) at anaerobic threshold, as well as peak O₂ pulse, workload, VE, and nadir VE/CO₂ were significantly higher in male patients than in female patients (P<0.05). Only oxygen uptake efficiency plateau (OUEP) showed a significantly higher difference in female than male patients (P<0.05). In addition, several CPET indices correlated with hemodynamic parameters, especially pulmonary vascular resistance (PVR), which was distinctly different between the sexes. Nadir VE/CO₂ was an independent predictor of PVR in male patients with CTEPH, whereas OUEP was an independent predictor of PVR in female patients with CTEPH.

Conclusion

Even after confounding for age and body mass index, different CPET measurements of gas exchange efficiency correlated with PVR differently between male and female patients. This potentially could be used to estimate the severity of CTEPH.

[Clinical and imaging features of pulmonary veno-occlusive disease and pulmonary capillary hemangioma]

Objective: To improve the diagnosis and treatment of the pulmonary veno-occlusive disease (PVOD) and pulmonary capillary hemangioma (PCH). Methods: The clinical features, radiological findings, laboratory testing and treatment in 8 cases of PVOD/PCH which was diagnosed from 2013 to 2017 were described. Results: PVOD/PCH was rare. The clinical symptoms were easily confused with IPAH, but the decrease of hypoxemia, clubbing, D(L)CO were more obvious, and the imaging features of HRCT were helpful for PVOD/PCH diagnosis. Combined with gene testing, it was helpful to diagnose PVOD/PCH and avoid the risk of surgical biopsy. Conclusion: PVOD and PCH are rare type of pulmonary vascular diseases. According to clinical manifestations, physical examination, pulmonary function test results, HRCT imaging, CPET and gene detection results, PVOD or PCH can be diagnosed.

Hemodynamic and gas exchange effects of inhaled iloprost in patients with COPD and pulmonary hypertension

Studies have shown that vasodilators such as iloprost can be useful for treating pulmonary hypertension (PH). However, in patients with COPD, vasodilators may inhibit hypoxic pulmonary vasoconstriction and impair gas exchange. The efficacy and safety of iloprost inhalation was assessed in 67 patients with PH associated with COPD (COPD-PH), diagnosed by right heart catheterization. Of these, 37 patients had severe PH (mean pulmonary arterial pressure [mPAP] >35 mmHg or mPAP 25-35 mmHg with low cardiac index [<2.0 L⋅min^-1⋅m^-2]). All patients received a single 20 µg dose of iloprost via a nebulizer (4.4 µg delivered at the mouthpiece). No serious adverse events were reported. Hemodynamic and gas exchange parameters (arterial blood gas and shunt fraction [Qs/Qt]) were measured or calculated at baseline and 10 min after iloprost inhalation. mPAP decreased by 2.1 mmHg (95% CI, -3.3 to -1.0), pulmonary vascular resistance (PVR) decreased by 62.4 dyn⋅s⋅cm^-5 (95% CI, -92.9 to -31.8), and cardiac output increased by 0.4 L⋅min^-1 (95% CI, 0.2-0.5). There was a more significant decline in PVR in patients with severe COPD-PH than in those with nonsevere COPD-PH. Hypoxemia and intrapulmonary shunt were more extreme in patients with severe COPD-PH. However, there were no significant differences in arterial blood gas and Qs/Qt between patients with nonsevere and severe forms of COPD-PH. In conclusion, iloprost improved pulmonary hemodynamics without detrimental effects on arterial oxygenation in patients with COPD-PH, even in those with severe PH. These findings suggest that the short-term use of iloprost in patients with COPD-PH is effective and well tolerated.

[Clinical analysis of Behçet disease associated with pulmonary vascular disease]

Objective: To investigate the clinical features, therapy and prognosis of Behcet's disease(BD) complicated with pulmonary vascular diseases (PVD). Methods: The clinical manifestation, hemodynamics, pulmonary artery angiographic findings, therapy and prognosis of PVD in BD in Shanghai Pulmonary Hospital from January 2009 to August 2016 were analyzed retrospectively. Results: Seven patients with average of (37±20) years were included. The ratio of male vs. female was 6∶1. Vascular involvement included pulmonary hypertension (PH) (4/7), pulmonary embolism (PE) (3/7) and pulmonary artery aneurysms (PAA) (3/7). All patients received immunosuppressive agents and all PH patients had therapy of PH target drugs. Three out of 4 PE patients underwent anticoagulant therapy. Conclusion: PVD is a rare complication of BD. The common clinical manifestations are PH, PE and PAA. Management of immunosuppressive agents may improve the prognosis and should be recommended.

[End tidal PCO(2) for evaluation of severity of disease in idiopathic pulmonary arterial hypertension and chronic thromboembolic pulmonary hypertension]

Objective: To explore the difference in end tidal PCO(2) (P(ET)CO(2)) between idiopathic pulmonary arterial hypertension (IPAH) and chronic thromboembolic pulmonary hypertension (CTEPH), and to analyze the correlation between P(ET)CO(2) and the indexes of disease severity in IPAH and CTEPH patients. Methods: Data were retrieved from 68 IPAH patients and 52 CTEPH patients who all had received right-heart catheterization, pulmonary function test and cardiopulmonary exercise testing at Shanghai Pulmonary Hospital from October 2011 to October 2014. In addition, other clinical parameters were also collected. Results: The IPAH group had a significantly higher mPAP, PVR [(60±16) mmHg (1 mmHg=0.133 kPa), (13±6) Wood U ] than the CTEPH group [(46±12) mmHg, (9±4) Wood U, t=4.90, 4.83, all P<0.01]. Meanwhile, the IPAH group had a lower percentage of predicted peakVO(2), oxygen pulse [(45±15)%, (60±22)%] compared with the CTEPH group [(53±16)%, (68±21)%, t=-2.42, -1.96, all P<0.05]. The value of P(ET)CO(2) at rest, AT, peak in the IPAH patients [(27±5), (28±7), (25±7) mmHg] were higher than those in the CTEPH patients [(24±4) mmHg, (23±6) mmHg, (21±6) mmHg, t=3.22-4.54, all P<0.01]. There was a significantly difference in P(ET)CO(2) at AT and peak between WHO-FC Ⅰ-Ⅱ and Ⅲ-Ⅳ subgroups in IPAH (t=2.55, 2.60, all P<0.05) and CTEPH (t=2.39, P<0.05), except for P(ET)CO(2) at peak in the CTEPH patients (t=1.71, P>0.05). A moderately inverse correlation was found between P(ET)CO(2) at AT and NT-proBNP in the IPAH group (r=-0.58, P<0.01), meanwhile P(ET)CO(2) at AT in the CTEPH group was weakly correlated with NT-proBNP (r=-0.34, P<0.05). Conclusions: Compared with the CTEPH patients, the IPAH patients had significantly decreased exercise capacity and increased P(ET)CO(2). P(ET)CO(2) could reflect the disease severity in both IPAH and CTEPH patients, being superior in IPAH than in CTEPH. Furthermore, P(ET)CO(2) at AT might be better than P(ET)CO(2) at peak in reflecting the ventilatory efficiency.

Sex-specific cardiopulmonary exercise testing indices related to hemodynamics in idiopathic pulmonary arterial hypertension

Background:

Many studies have highlighted sex preponderance in idiopathic pulmonary arterial hypertension (IPAH). It is well established that there are differences in exercise capacities in the two sexes but how much of that difference reflects on disease severity or correlates to markers of severity in the two sexes is still not clear. Right heart catheterization (RHC) and cardiopulmonary exercise testing (CPET) have been widely used for assessing functional capacity, prognosis and treatment response in IPAH. We aimed to investigate the ‘sex-specific’ CPET parameters in relation to hemodynamics in IPAH.

Methods:

Data were retrieved from 30 males and 53 females [mean ± standard deviation (SD) age: 39.6 ± 17.2 and 37.5 ± 12.0] stable IPAH patients who underwent both RHC and CPET at Shanghai Pulmonary Hospital from 2010 to 2016. Univariate and forward/backward multiple stepwise regression analysis was performed to assess the prognostic value of CPET and hemodynamic parameters.

Results:

There were no significant differences in clinical variables between men and women. Peak workload, peak oxygen uptake, anaerobic threshold (AT), peak minute ventilation, carbon dioxide output, O₂ pulse and oxygen uptake efficiency slope were significantly higher in men compared with women (p < 0.05). Several CPET indexes correlated with hemodynamics. Pulmonary vascular resistance (PVR) and cardiac output (CO) were distinctly different between the sexes. Peak end-tidal partial pressure of CO₂ (P_ETCO₂) was an independent predictor of PVR elevation in all patients and in men. Peak maximum oxygen consumption (VO₂) was independently predictive of CO decline in all patients and in men. Only peak O₂ pulse was an independent predictor of increased PVR and decreased CO in women.

Conclusions:

Even after adjusting for age, body mass index and World Health Organization functional class, different CPET parameters correlated with PVR elevation and CO decline in men and women differently, which could potentially better predict severity in men and women with IPAH.

Chronotropic Incompetence and its Relation to Exercise Intolerance in Chronic Obstructive Pulmonary Disease

BACKGROUND

To study the relationship between chronotropic incompetence (CI) and disease severity and to assess the effect of CI on exercise capacity in patients with chronic obstructive pulmonary disease (COPD).

MATERIALS AND METHODS

Arterial blood gas analysis, pulmonary function test and cardiopulmonary exercise testing were conducted in 60 patients with stable COPD and 45 healthy volunteers. CI was defined using the chronotropic response index (CRI = (peak heart rate-resting heart rate) / (220-age-resting heart rate). Based on CRI, patients with COPD were divided into the normal chronotropic group (n = 23) and CI group (n = 37).

RESULTS

CI was present in 61.7% of the patients with COPD. Exercise capacity (peak oxygen uptake as percentage of predicted value, peak VO₂%pred), peak heart rate and CRI were significantly lower in patients with COPD than in controls. However, resting heart rate was significantly higher than in controls. FEV₁%pred and exercise capacity were significantly decreased in the CI group when compared with those in the normotropic group. There was significant association between CRI with FEV₁%pred and peak VO₂%pred. Multivariate regression analysis showed that CRI and FEV₁%pred were independent predictors of exercise capacity in patients with COPD. A cutoff of 0.74 for the CRI showed a specificity of 94.1% in predicting patients with a peak VO₂%pred < 60%.

CONCLUSIONS

CRI was associated with disease severity in patients with COPD. CI may be an important parameter to reflect exercise capacity in patients with COPD.

Cardiopulmonary exercise testing improves diagnostic specificity in patients with echocardiography-suspected pulmonary hypertension

BACKGROUND

Doppler echocardiography is usually the first diagnostic investigation for patients suspected with pulmonary hypertension (PH), but it is often inaccurate when used alone, especially in mild PH.

HYPOTHESIS

Cardiopulmonary exercise testing (CPET) may serve as a complementary tool to improve diagnostic accuracy in echocardiography-suspected "PH possible" patients.

METHODS

Eighty-eight consecutive patients with suspected PH (referred to as "PH possible" hereafter) based on echocardiography were included in the study. CPET was assessed subsequently and PH was confirmed by right-heart catheterization in all subjects. We analyzed CPET data from patients and derived a CPET prediction rule to hemodynamically differentiate PH.

RESULTS

Eighty-eight patients (27 patients with confirmed PH, and PH ruled out in 61 patients) were included in the study. Compared with non-PH patients, the PH subjects had lower peak oxygen uptake (VO₂ ), aerobic capacity (AT), peak partial pressure of end-tidal CO₂ (P_ET CO₂ ), oxygen uptake efficiency plateau (OUEP), and oxygen uptake efficiency slope (OUES), along with higher minute ventilation (VE)/carbon dioxide output (VCO₂ ) slope and lowest VE/VCO₂ (P < 0.001). VE/VCO₂ slope and AT were independent predictors of PH derived from multivariate logistic regression adjusted for age and body mass index. A score combining VE/VCO₂ slope and AT reached a high area under the curve value of 0.98. A score ≥0.5 had 95% specificity and 92.6% sensitivity for diagnosis of PH.

CONCLUSIONS

A score combining VE/VCO₂ slope and AT provides high specificity in screening out PH from a pool of echocardiography-suspected PH patients.

Diffuse Pulmonary Arteriovenous Fistulas With Pulmonary Arterial Hypertension: Case Report and Review

Pulmonary arteriovenous fistulas (PAVFs) are rare. Diffuse type PAVFs with pulmonary arterial hypertension (PAH) are even rarer and can elude anatomy imaging like a plain chest film or a computed tomography. The rapid blood flow that ensues due to lack of a capillary bed leads to various degrees of ischemia depending on the number and size of the PAVF. This is a case report of diffuse PAVF in a patient with PAH.This case report describes a patient with recurrent hemoptysis and chest pain. Systemic examination was unremarkable except for P2 attenuation on auscultation. Echocardiograghy showed confirmed pulmonary hypertension with mild dilation of right atrium and ventricle and a tricuspid regurgitation pressure gradient of 40 mm Hg and ruled out congenital heart diseases. Right heart catheterization revealed precapillary PAH with mean pulmonary arterial pressure of 88 mm Hg. Pulmonary angiography showed enlarged pulmonary arterial trunk and diffuse spiral tortuous pulmonary arterial branches indicting diffuse PAVFs. The patient was diagnosed as PAH and began treatment of 25 mg tid of sildenafil.The case highlights a rare and unique presentation of PAH.

Change in pulmonary function in chronic obstructive pulmonary disease stage 0 patients

This study aims to elucidate the change in pulmonary function in stage 0 COPD patients. A total of 48 stage 0 COPD patients and 46 healthy adults were included in the study. The status of their pulmonary function was determined by an impulse oscillometry (IOS) system, and the spirometric indexes such as forced vital capacity, maximum expiratory flow-volume (MEFV) curve, total respiratory impedance (Zrs) and respiratory resistance (Rrs) between the two groups were compared. Significant decreases in the values of forced expiratory flow (FEF) at both 75% and 50% of the vital capacity of the predicted value (EF75/pre and FEF50/pre) were detected in stage 0 COPD patients compared with those in the control (P < 0.05). Significant increases were found in the resonant frequency (Fres) (14.37±3.63 VS 11.26±2.61), total respiratory impedance (Z5) compared with the prediction (Z5/pre) (135.65±19.37 VS 104.69±20.64), total airway resistance at 5 Hz (R5) compared with prediction (R5/pre) (128.46±20.14 VS 100.60±20.98) and peripheral airway resistance (R5-R20) compared with prediction (R5-R20/pre) (282.34±192.83 VS 109.31±80.05) in the study group compared with those in the control(all P < 0.05). The reactance at 5 Hz (X5) (-0.14±0.05 VS -0.08±0.05) in the stage 0 COPD group was markedly lower than that in the healthy group (P < 0.05). Disturbance in the small airway may be detected by the MEFV curve and IOS, and these indexes would be valuable in diagnosing stage 0 COPD.

Nitric oxide in human gingival crevicular fluid after orthodontic force application

Nitric oxide (NO) is involved in bone remodelling and has been shown to play a role in regulating the rate of orthodontic tooth movement (OTM) in rat models. In humans, however, the role of NO in OTM remains less clear. In this study, NO concentration in gingival crevicular fluid (GCF) was measured in patients undergoing orthodontic treatment. Thirteen male participants (ages 11-18 years) planned for non-extraction fixed orthodontic therapy were recruited. Samples of GCF were collected from each maxillary central incisor and first and second molar immediately before (T0), 1h after (T1), and 3-4 days after (T2) application of light orthodontic forces. The maxillary second molars were not included in the appliance and served as controls. Measureable NO levels were consistently obtained from all sampled sites. Total NO levels showed significantly higher NO levels (p<0.05) at T1 at the buccal surfaces of the central incisors when compared to the first and second molars. The results indicate a possible role for NO in OTM at the pressure sites of incisors at early time points. Further studies are required to determine whether NO levels in the periodontal ligament tissues of human teeth during OTM are affected by a force gradient and the magnitude of the applied force.

[Protection of amrinone against lung injury induced by ischemia/reperfusion in rats]

OBJECTIVE

To investigate the protective effect of amrinone against experimental lung ischemia /reperfusion (I/R) injury.

METHODS

Twenty-four Sprague-Dawley rats were randomly divided into 3 groups (n=8 each): sham- operated group, I/R group, and amrinone-treated I/R group (AMR group). The left lung of rats was subjected to ischemia for 90 minutes, followed by reperfusion for 2 hrs, to induce an I/R lung injury model. The rats of the AMR group received amrinone (10 mg/kg) intravenously 30 minutes before ischemia and 5 minutes before reperfusion. After 2 hrs of reperfusion, carotid artery blood was collected for blood-gas analysis and detection of serum levels of IL-1beta, IL-8 and TNF-alpha. The left lung was removed for detection of the lung wet/dry ratio, the erythrocuprein (SOD) activity and the malonaldehyde (MDA) content as well as the pathological changes.

RESULTS

After 2 hrs of reperfusion, there were no significant differences in artery partial pressure of oxygen (PO2) and partial pressure of carbon dioxide (PCO2) among the three groups. The lung wet/dry ratio (5.3 +/- 0.5 vs 4.8 +/- 0.1) and the MDA content (0.66 +/- 0.16 nmol/mg prot vs 0.47 +/- 0.06 nmol/mg prot) in the I/R group were significantly higher than those of the sham-operated group (P <0.05). The administration of amrinone markedly reduced the lung wet/dry ratio (4.8 +/- 0.2) and the MDA content (0.51 +/- 0.09 nmol/mg prot) and increased the SOD activity (54.7 +/- 6.8 vs 39.3 +/- 3.0 U/mg prot) when comparing the I/R group (P < 0.05). The serum levels of IL-1beta, IL-8 and TNF-alpha in the I/R group were 22.08 +/- 3.85, 21.92 +/- 5.56 and 30.50 +/- 3.77 pg/mL respectively, which were significantly higher than those of the sham-operated group. The AMR group showed lower serum levels of IL-1beta, IL-8 and TNF-alpha (16.66 +/- 3.02,14.73 +/- 2.75 and 22.48 +/- 3.82 pg/mL, respectively) compared with the I/R group (P < 0.01). The pathologic examination displayed that the lung tissue structure was normal and there was no hyperemia in the sham-operated and the AMR groups. The lung tissue structure of the I/R group was nearly normal but there were hyperemia and more inflammatory cells than the sham-operated and the AMR groups.

CONCLUSIONS

Amrinone has protections against lung I/R injury, possibly through its anti-oxidation effects and an inhibition of inflammation factors releasing.

Characterization of olfactory nerve abnormalities in Twirler mice

The sense of smell is perceived by olfactory receptor neurons (ORN) present in the olfactory epithelium located in the posterosuperior aspect of the nasal cavity. The axons of these ORN migrate to the olfactory bulb (OB), forming a nervous layer on the outermost part of the bulb, and finally synapse in glomerular structures in the OB. The ORN are unique in that they are constantly being renewed throughout life. We characterized the defects in the nasal cavity and olfactory nervous supply of Twirler (Tw) mice by histological and immunohistochemical means. Tw homozygotes have previously been shown to present with midfacial abnormalities in the form of clefts of the lip and palate (Lyon, 1958; Gong et al., 2000). We found that in the Tw homozygotes, the OB was abnormally shaped, the skeletal framework underlying the OB was disrupted, and the morphology of the nasal cavity was altered with poorly defined nasal turbinates. Immunohistochemical staining with antibodies that marked nerves in general (PGP 9.5) and mature ORN (omp) in the olfactory epithelium at two different embryonic stages and in newborn mice revealed the stratification of the olfactory epithelium in Tw homozygotes, albeit slightly thinner compared to wildtype. A striking difference in the olfactory epithelium was the lack of differentiation of the ORN in Tw homozygotes and the reduced axonal input to the OB. In Tw homozygotes at 14.5 days of embryonic development, the presence of many mature ORN found randomly in the mesenchyme suggests the loss of olfactory pathfinding cues to the OB. It is believed that the lack of appropriate pathfinding cues observed in the Tw homozygotes was responsible for the OB not having the appropriate trophic effect on the development and maturation of the ORN as had been observed in partially bulbectomized animals. The defects in the Twirler may prove to be a valuable system to analyze problems in olfactory pathfinding and maturation.

Palatal development in Twirler mice

OBJECTIVE

The development of the secondary palate of Twirler (Tw) mice was characterized, and a quantitative coronal plane evaluation of the width and length of the craniofacial regions of homozygous mutant embryos was conducted.

RESULTS AND CONCLUSIONS

The secondary palatal shelves were retarded in growth and the timing of elevation from a vertical to horizontal position. The homozygous Tw embryos, when compared with their wild-type littermates, also had a significantly wider midface. It is not surprising, therefore, that the short palatal shelves in a wide midface resulted in cleftings of the secondary palate observed in all homozygous Tw mice. These findings are consistent with similar studies in humans and other murine models.

Tumorhead, a Xenopus gene product that inhibits neural differentiation through regulation of proliferation

Tumorhead (TH) is a novel maternal gene product from Xenopus laevis containing several basic domains and a weak coiled-coil. Overexpression of wild-type TH resulted in increased proliferation of neural plate cells, causing expansion of the neural field followed by neural tube and craniofacial abnormalities. Overexpressed TH protein repressed neural differentiation and neural crest markers, but did not inhibit the neural inducers, pan-neural markers or mesodermal markers. Loss of function by injection of anti-TH antibody inhibited cell proliferation. Our data are consistent with a model in which tumorhead functions in regulating differentiation of the neural tissues but not neural induction or determination through its effect on cell proliferation.