Sex-biased TGFβ signalling in pulmonary arterial hypertension

Burden of pulmonary arterial hypertension in Asia from 1990 to 2021: Findings from Global Burden of Disease Study 2021

BACKGROUND

Pulmonary arterial hypertension (PAH) presents a significant health burden in Asia and remains a critical challenge. This study aims to delineate the PAH burden in Asia from 1990 to 2021.

METHODS

Using the latest data from the Global Burden of Disease 2021, we evaluated and analyzed the distributions and patterns of PAH disease burden among various age groups, sexes, regions, and countries in Asia. Additionally, we examined the associations between PAH disease burden and key health system indicators, including the socio-demographic index (SDI) and the universal health coverage (UHC) index.

RESULTS

In 2021, there were 25,989 new PAH cases, 103,382 existing cases, 13,909 PAH-associated deaths, and 385,755 DALYs attributed to PAH in Asia, which accounted for approximately 60% of global PAH cases. The age-standardized rates (ASRs) for prevalence and deaths were 2.05 (95% uncertainty interval [UI]: 1.66-2.52) per 100,000 population and 0.31 (95% UI: 0.23-0.38) per 100,000 population, respectively. From 1990 to 2021, Asia reported the lowest ASRs for PAH prevalence but the highest ASRs for deaths compared to other continents. While the ASRs for prevalence increased slightly, ASRs for mortality and DALYs decreased over time. This increasing burden of PAH was primarily driven by population growth and aging. The burden was especially pronounced among individuals aged ≥60 years and <9 years, who collectively accounted for the majority of deaths and DALYs. Moreover, higher SDI and UHC levels were linked to reduced incidence, but higher prevalence rates.

CONCLUSIONS

Although progress has been made in reducing PAH-related mortality and DALYs, the disease continues to impose a substantial burden in Asia, particularly among older adults and young children. Region-specific health policies should focus on improving early diagnosis, expanding access to treatment, and effectively addressing the growing PAH burden in the region.

Dual inhibition of TGFβ and PDGF improves RV remodeling and function in response to RV pressure or volume-loading

Right ventricular (RV) pressure and volume loading induce RV fibrosis in association with RV dysfunction, morbidity, and mortality in repaired tetralogy of Fallot. Transforming-growth factor-β1 (TGFβ1) and platelet-derived growth factor (PDGF) activate common downstream signaling pathways via TGFβ canonical and non-canonical signaling to promote increased fibroblast activation, proliferation, and fibrosis in other organs. However, the role of PDGF and TGFβ canonical and non-canonical signaling in RV fibrosis is incompletely characterized. Here, we investigate whether dual inhibition of TGFβ and PDGF, using Tranilast (TRN), improves RV remodeling in response to pulmonary artery banding (PAB) or pulmonary regurgitation (PR). TRN reduced TGFβ canonical signaling in PAB rats associated with improved RV fibrosis, hypertrophy, and RV function. In response to PR, TRN reduced PDGFRβ expression and normalized ERK1/2 activity, which were associated with reduced RV hypertrophy and improved diastolic relaxation. We identify that PDGF drives RV fibroblast proliferation and activation via SMAD2/3, JNK, and β-catenin signaling. Our studies suggest that TGFβ and PDGF are interconnected drivers of RV fibrosis and hence synergistic targets to improve RV remodeling in RV pressure and volume loading.

Androgen receptor inhibitor ameliorates pulmonary arterial hypertension by enhancing the apoptosis level through suppressing the Notch3/Hes5 pathway

Background

Pulmonary arterial hypertension (PAH) exhibits significant gender differences in prognosis, with male patients typically showing worse outcomes than females. These disparities may stem from differences in androgen receptor expression and activity. Clinical studies suggest that the androgen receptor plays a crucial role in the pathophysiology of PAH, influencing disease progression and treatment response. Despite the lack of targeted therapies for PAH, these findings have spurred investigations into the potential therapeutic role of androgen receptors. This study explores the role of androgen receptors in PAH and evaluates their therapeutic potential.

Methods

PAH was induced in rats via intraperitoneal injection of monocrotaline (MCT). Following model establishment, Enzalutamide was administered every 3 days at 10 mg/kg once for a total of 7 times (21 days). A mouse model of PAH was developed by subcutaneously injecting SU5416 and exposing the mice to hypoxia. Androgen receptor knockout (AR-/-) mice were also utilized to investigate the role of androgen receptors in disease progression. Key indicators were compared across groups. The in vivo mechanisms through which androgen receptors influence PAH were examined in both rat and mouse models. Additionally, mouse pulmonary artery endothelial cells (PAECs) were cultured under hypoxic conditions to create an in vitro model of PAH, facilitating further investigation into the role of androgen receptors in disease pathogenesis.

Results

Compared to the normal group, the model group exhibited significantly increased androgen receptor expression in rats, mice, and mPAECs. This was accompanied by pronounced pulmonary artery wall thickening, right ventricular hypertrophy, pulmonary fibrosis, elevated pulmonary artery pressure, and a reduced level of apoptosis both in vivo and in vitro. Furthermore, activation of the Notch3/Hes5 signaling pathway was observed. However, treatment with androgen receptor inhibitors or gene knockout significantly ameliorated these pathological changes. Apoptosis levels increased both in vivo and in vitro, and the activation of the Notch3/Hes5 signaling pathway was effectively inhibited.

Conclusion

Our findings suggest that in both animal models and the hypoxic mPAECs, inhibition of androgen receptor expression leads to increased apoptosis via suppression of the Notch3/Hes5 signaling pathway. This mechanism likely contributes to the therapeutic effects observed, providing insights for potential treatment strategies targeting androgen receptors in pulmonary arterial hypertension.

Increased risk for thoracic aneurysms in female and familial abdominal aortic aneurysm patients

BACKGROUND

Thoracic aortic aneurysms (TAAs) occur more frequently in abdominal aortic aneurysm (AAA) patients than in the general population. The aim of the study was to investigate which AAA patients have an increased risk of developing TAA or thoraco-abdominal aortic aneurysm (TAAA), and if sex, genetic susceptibility for aneurysms, or conventional cardiovascular risk factors affect this risk.

METHODS

Repeated computed tomography scans from consecutively diagnosed AAA patients were evaluated retrospectively to determine the prevalence, sequence, and location of multiple aortic aneurysms. Effects of sex, genetic predisposition for aneurysms (familial aneurysm, the presence of [likely] pathogenic variants in known aneurysm genes), and cardiovascular risk factors (age, smoking, hypertension, diabetes mellitus, and hypercholesterolemia) on the risk for TAA were analyzed. Five-year survival was used to evaluate the impact of having thoracic aneurysms on survival of AAA patients.

RESULTS

On the first computed tomography scan, 10.8% of AAA patients had a TAA. During follow-up, an additional 5.1% of the AAA patients developed TAA and 2.4% developed TAAA. Female patients had a two-fold increase in risk for TAA, in particular for aneurysms of the descending aorta. A two-fold increase in risk for ascending TAA was observed in AAA patients reporting familial aneurysms. The 5-year survival of female TAAA patients was lower than that of AAA patients, independent of having a TAA.

CONCLUSIONS

Female AAA patients had a two-fold increase in risk for TAA, particularly in the descending aorta. Familial AAA patients had a two-fold increase in aneurysm risk for ascending aortic aneurysms. TAAA patients had a lower survival compared with TAA or AAA patients, specifically among female TAAA patients. TAA and TAAA developed during follow-up. Therefore, follow-up imaging of both the ascending and descending aorta after diagnosis of AAA may improve early detection of multiple aneurysms.

Impact of Excess Activin A on the Lipids, Metabolites, and Steroids of Adult Mouse Reproductive Organs

Bioactivity of the hormone and growth factor activin A is central to fertility and health. Dysregulated circulating activin levels occur with medication usage and multiple pathological conditions. The inhibin-alpha knockout mouse (InhaKO) models chronic activin elevation and unopposed activin A bioactivity. In InhaKO fetal testes, lipid droplet, steroid profiles, and seminiferous cords are abnormal; adults develop gonadal and adrenal tumors due to chronic activin A excess exposure. Here we address how this exposure affects lipid, metabolite, and steroid composition in whole testes, ovaries, and adrenals of adult InhaKO mice using histological, transcriptomic, and mass spectrometry (MS) methods, including MS imaging (matrix-assisted laser desorption/ionization-MS imaging). Matrix-assisted laser desorption/ionization-MS imaging delineated spatial lipid profiles within interstitial, inner cord, and outer cord regions containing normal spermatogenesis; these differed between wild-type and KO samples. In proximity to tumors, lipids showed distinctive distribution patterns both within and adjacent to the tumor. Significantly altered lipids and metabolic profiles in whole InhaKO testes homogenates were linked to energy-related pathways. In gonads and adrenal glands of both sexes, steroidogenic enzyme transcription, and steroids are different, as expected. Lipid profiles and steroidogenic enzyme proteins, HSD3B1 and CYP11A1, are affected within and near gonadal tumors. This documents organ-specific effects of chronic activin A elevation on lipid composition and cellular metabolism, in both histologically normal and tumor-affected areas. The potential for activin A to influence numerous steroidogenic processes should be considered in context and with spatial precision, particularly in relationship to pathologies.

Trends in pulmonary arterial hypertension: insights from Global Burden of Disease 1990-2021

OBJECTIVE

This study aimed to assess the global, regional and national burden of pulmonary arterial hypertension (PAH) from 1990 to 2021 using data from the Global Burden of Disease Study 2021. The focus was on evaluating trends in incidence, prevalence, mortality and disability-adjusted life-years (DALYs) associated with PAH and examining these trends by age, gender and sociodemographic index (SDI).

DESIGN

This is a systematic analysis leveraging data from the Global Burden of Disease Study 2021. The analysis focused on both crude and age-standardised rates to track temporal trends in PAH burden, with data stratified by region and SDI.

SETTING

The study used global, regiona, and national data from 204 countries and regions, spanning from 1990 to 2021.

PARTICIPANTS

The participants in this study include individuals diagnosed with PAH, with data representing populations globally, categorised by age, gender and SDI.

PRIMARY AND SECONDARY OUTCOME MEASURES

Primary outcome measures included global, regional and national incidence, prevalence, mortality and DALYs related to PAH. Secondary outcomes consisted of age-standardised rates (age-standardised incidence rate (ASIR), age-standardised mortality rate (ASMR)) and trends over the study period. A key strength of this study is the detailed stratification by SDI, revealing how PAH burden varies across different socio-economic settings. This extended temporal analysis offers new insights into long-term trends, highlighting the rising burden in lower-SDI regions and significant regional disparities in disease management and outcomes.

RESULTS

From 1990 to 2021, global PAH cases showed substantial increases in both incidence (85.62%) and prevalence (81.46%), while age-standardised rates remained stable. Across SDI levels, high-SDI regions maintained stable ASIRs (0.37 per 100 000) with a slight decline (estimated average percentage change (EAPC) -0.06%), while low-SDI regions demonstrated the most significant reduction (EAPC -0.30%). Deaths increased by 48.36% globally, though the ASMR decreased from 0.35 to 0.27 per 100 000. The disease burden measured by DALYs decreased by 6.59%, with high-SDI regions showing better improvements in age-standardised DALY rates (-1.39% EAPC) compared with other SDI levels. Gender analysis revealed persistent female predominance (female-to-male ratio 1.62:1), particularly pronounced in populations over 50 years across all SDI quintiles.

CONCLUSIONS

While global age-standardised rates have declined, PAH remains a significant global health burden, particularly in low-SDI regions. These findings underscore the need for targeted prevention and intervention strategies, especially for high-risk populations, such as females and the elderly, to reduce the global health impact of PAH.

The lncRNA DSCR9 is modulated in pulmonary arterial hypertension endothelial cell models and is associated with alterations in the nitric oxide pathway

Long non-coding RNA (lncRNA) may be involved in dysfunction of pulmonary artery endothelial cells (PAEC) and, thus, in pulmonary arterial hypertension (PAH) pathobiology. We screened the RNA expression profile of commercial human PAEC (hPAEC) exposed to increased hydrostatic pressure, and found that the lncRNA Down syndrome critical region 9 (DSCR9) was the most regulated transcript (log2FC 1.89 vs control). We confirmed by RT-qPCR that DSCR9 levels were higher in PAEC isolated from patients with idiopathic PAH (iPAH-PAEC), as well as in induced pluripotent stem cell-derived endothelial cells (iPSC-EC) from a patient with BMPR2-mutated PAH, than in relevant controls. Moreover, a re-analysis of the publicly available GSE117261 microarray dataset revealed that DSCR9 was upregulated in the lung tissue of PAH patients. In silico simulation indicated that DSCR9 would be mainly located in the nucleus and could interact with calcium/calmodulin-dependent protein kinase II beta (CAMK2B) and nitric oxide synthase 3 (NOS3, encoding eNOS). CAMK2B levels resulted 3.4-fold higher (p < 0.05) in iPAH-PAEC transfected with a DSCR9-GFP carrying plasmid than with a GFP-only-carrying one. A trend for higher NOS3 expression was also noted. GFP immunostaining was predominantly nuclear and cytoplasmic upon DSCR9-GFP or GFP-only transfection, respectively. CAMK2B and NOS3 mRNA were also higher in iPAH-PAEC than control-PAEC in basal conditions. Instead, variations in total and phosphorylated CAMK2B, eNOS, and NO synthesis were inconsistent. We conclude that DSCR9 is upregulated in PAH-related endothelial cell models and influences CAMK2B and NOS3 expression. Future studies are necessary to determine whether DSCR9 affects NO availability, including in PAH.

Assessment of Riociguat-related adverse events: a disproportionality analysis utilizing the FDA adverse event reporting system database

BACKGROUND

Riociguat is a novel soluble guanylate cyclase stimulator approved for the treatment of pulmonary arterial hypertension (PAH). Despite its widespread use, there has been a lack of large-scale studies assessing the adverse events (AEs) associated with this medication.

RESEARCH DESIGN AND METHODS

This study aimed to evaluate the AEs related to Riociguat by analyzing data from the FDA Adverse Event Reporting System (FAERS) from Q4 2013 to Q1 2024. A total of 12,149 AE reports were analyzed using four different disproportionality signal detection methodologies to identify significant AEs associated with Riociguat.

RESULTS

The analysis revealed 117 preferred terms (PTs) with significant disproportionality signals across all four methods. Among these, common AEs included 'headache,' 'dizziness,' 'hypotension,' 'nausea,' 'fall,' and 'loss of consciousness.' Notably, several unexpected AEs, such as 'fatigue,' 'malaise,' 'asthenia,' 'feeling abnormal,' and 'pain in extremity,' were identified, which were not highlighted in the product's package insert. Additionally, gender-specific differences were observed in certain adverse events.

CONCLUSIONS

This study offers insights into Riociguat's side effects. Clinicians should monitor patients closely for unexpected symptoms like limb pain and fatigue, paying particular attention to male patients, as some AEs occur more frequently in this group.

Sex Dimorphism in Pulmonary Arterial Hypertension Associated With Autoimmune Diseases

Pulmonary hypertension is a rare, incurable, and progressive disease. Although there is increasing evidence that immune disorders, particularly those associated with connective tissue diseases, are a strong predisposing factor in the development of pulmonary arterial hypertension (PAH), there is currently a lack of knowledge about the detailed molecular mechanisms responsible for this phenomenon. Exploring this topic is crucial because patients with an immune disorder combined with PAH have a worse prognosis and higher mortality compared with patients with other PAH subtypes. Moreover, data recorded worldwide show that the prevalence of PAH in women is 2× to even 4× higher than in men, and the ratio of PAH associated with autoimmune diseases is even higher (9:1). Sexual dimorphism in the pathogenesis of cardiovascular disease was explained for many years by the action of female sex hormones. However, there are increasing reports of interactions between sex hormones and sex chromosomes, and differences in the pathogenesis of cardiovascular disease may be controlled not only by sex hormones but also by sex chromosome pathways that are not dependent on the gonads. This review discusses the role of estrogen and genetic factors including the role of genes located on the X chromosome, as well as the potential protective role of the Y chromosome in sexual dimorphism, which is prominent in the occurrence of PAH associated with autoimmune diseases. Moreover, an overview of animal models that could potentially play a role in further investigating the aforementioned link was also reviewed.

CD137 Signaling Mediates Pulmonary Artery Endothelial Cell Proliferation Under Hypoxia By Regulating Mitochondrial Dynamics

Altered mitochondrial dynamics affect pulmonary artery endothelial cells (PAECs) proliferation, contributing to the development of pulmonary hypertension. CD137 signaling promotes mitochondrial fission. We hypothesize CD137 signaling is involved in the excessive proliferation of PAECs. The levels of CD137 protein were increased in the lung tissue of hypoxic mice and hypoxic-stimulated PAECs. Activation of CD137 signal in hypoxic-PAECs upregulated the levels of hypoxia-inducible factor-2α (HIF-2α), glucose transporters type 4, the lactate transporter monocarboxylate transporter 4, key glycolysis rate-limiting enzymes and promoted mitochondrial division; moreover, increased glucose uptake, lactic acid and ATP production and proliferative cells were observed in these PAECs. Whereas, knockdown HIF-2α reversed CD137 signal-mediated effects in PAECs mentioned above. Compared with wild-type mice, the proliferation of PAECs and the percentage of vascular lateral wall thickness decreased in CD137 knockout mice. Together, CD137 signal participated in pulmonary vascular remodeling through the regulation of mitochondrial dynamics dependent on HIF-2α in PAECs.

A peripheral system disease-Pulmonary hypertension

Pulmonary hypertension (PH) is a cardiovascular disorder characterized by substantial morbidity and mortality rates. It is a chronic condition characterized by intricate pathogenesis and uncontrollable factors. We summarized the pathological effects of estrogen, genetics, neuroinflammation, intestinal microbiota, metabolic reorganization, and histone modification on PH. PH is not only a pulmonary vascular disease, but also a systemic disease. The findings emphasize that the onset of PH is not exclusively confined to the pulmonary vasculature, consequently necessitating treatment approaches that extend beyond targeting pulmonary blood vessels. Hence, the research on the pathological mechanism of PH is not limited to target organs such as pulmonary vessels, but also focuses on exploring other fields (such as estrogen, genetics, neuroinflammation, intestinal microbiota, metabolic reorganization, and histone modification).

Roles of LncRNAs in the Pathogenesis of Pulmonary Hypertension

Pulmonary hypertension (PH) is a persistently progressive, incurable, multifactorial associated fatal pulmonary vascular disease characterized by pulmonary vascular remodeling. Long noncoding RNAs (lncRNAs) are involved in regulating pathological processes such as pulmonary vasoconstriction, thickening, remodeling, and inflammatory cell infiltration in PH by acting on different cell types. Because of their differential expression in PH patients, as demonstrated by the observation that some lncRNAs are significantly upregulated while others are significantly downregulated in PH patients, lncRNAs are potentially useful biomarkers for assessing disease progression and diagnosis or prognosis in PH patients. This article provides an overview of the different mechanisms by which lncRNAs are involved in the pathogenesis of PH.

Novel insights and new therapeutic potentials for macrophages in pulmonary hypertension

Inflammation and immune processes underlie pulmonary hypertension progression. Two main different activated phenotypes of macrophages, classically activated M1 macrophages and alternatively activated M2 macrophages, are both involved in inflammatory processes related to pulmonary hypertension. Recent advances suggest that macrophages coordinate interactions among different proinflammatory and anti-inflammatory mediators, and other cellular components such as smooth muscle cells and fibroblasts. In this review, we summarize the current literature on the role of macrophages in the pathogenesis of pulmonary hypertension, including the origin of pulmonary macrophages and their response to triggers of pulmonary hypertension. We then discuss the interactions among macrophages, cytokines, and vascular adventitial fibroblasts in pulmonary hypertension, as well as the potential therapeutic benefits of macrophages in this disease. Identifying the critical role of macrophages in pulmonary hypertension will contribute to a comprehensive understanding of this pathophysiological abnormality, and may provide new perspectives for pulmonary hypertension management.

Maternal Exercise Prior to and during Gestation Induces Sex-Specific Alterations in the Mouse Placenta

While exercise (EX) during pregnancy is beneficial for both mother and child, little is known about the mechanisms by which maternal exercise mediates changes in utero. Six-week-old female C57BL/6 mice were divided into two groups: with (exercise, EX; N = 7) or without (sedentary, SED; N = 8) access to voluntary running wheels. EX was provided via 24 h access to wheels for 10 weeks prior to conception until late pregnancy (18.5 days post coitum). Sex-stratified placentas and fetal livers were collected. Microarray analysis of SED and EX placentas revealed that EX affected gene transcript expression of 283 and 661 transcripts in male and female placentas, respectively (±1.4-fold, p < 0.05). Gene Set Enrichment and Ingenuity Pathway Analyses of male placentas showed that EX led to inhibition of signaling pathways, biological functions, and down-regulation of transcripts related to lipid and steroid metabolism, while EX in female placentas led to activation of pathways, biological functions, and gene expression related to muscle growth, brain, vascular development, and growth factors. Overall, our results suggest that the effects of maternal EX on the placenta and presumably on the offspring are sexually dimorphic.