Metabolism in Pulmonary Hypertension

Multi-omics analysis of two rat models reveals potential role of vesicle transport and autophagy in right ventricular remodeling

Right ventricular failure as a severe consequence of pulmonary arterial hypertension (PAH) is an independent risk factor for poor prognosis, although the pathogenesis of right ventricular remodeling (RVR) remains unclear. Exploring the shared molecular pathways and key molecules in the right ventricle in monocrotaline (MCT) and pulmonary artery banding (PAB) rat models may reveal critical RVR mechanisms. Untargeted proteome and metabolome analysis were performed on the right ventricular myocardium of two RVR models (MCT-induced PAH rats and PAB-operated rats) to identify the altered proteins and metabolites, followed by validation using parallel reaction monitoring analysis and quantitative real-time polymerase chain reaction (qPCR). The multi-omics profiles of MCT and PAB rat models were compared to explore the key dysregulated molecules and pathways in RVR. Our proteomics study identified 25 shared RVR-altered differentially expressed proteins. Multiple common biological pathways were identified between PAB and MCT rat models, encompassing myocardial remodeling and energy metabolism alternation, etc. Various molecules and pathways related to vesicle transport and autophagy were identified, including nidogen-1, the soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs) signaling pathway, and the microautophagy pathway (all previously unreported in RVR). Glycerophospholipid metabolism was the sole statistically significant common metabolic pathway enriched by metabolomics. Underreported biological processes, including vesicle transport and autophagy, may contribute to the pathophysiology of PAH-induced RVR.

The relationship between hepatic steatosis index and hypertension: NHANES 2011-2018

BACKGROUND

The Hepatic Steatosis Index (HSI) serves as a non-invasive indicator for assessing liver fat accumulation. Its potential association with hypertension has garnered increasing attention, as metabolic dysfunctions, including hepatic steatosis, may contribute to elevated blood pressure via mechanisms such as insulin resistance and chronic inflammation.

METHODS

Utilizing data from the NHANES database (2011-2018), the HSI was calculated on the basis of alanine aminotransferase (ALT), aspartate aminotransferase (AST) and BMI.The association between HSI and hypertension was assessed by univariate analysis, weighted multivariate Logistic regression, and restricted cubic spline (RCS) models. Subgroup analyses were performed to increase the reliability of the data.

RESULTS

This cross-sectional study analysed data from 17,501 adults (NHANES 2011-2018) to assess the association between HSI and hypertension. Of these, 9,890 (56.51%) were diagnosed with hypertension.In the unadjusted model, HSI demonstrated a statistically significant correlation with hypertension, showing an odds ratio (OR) of 1.05 (95% confidence interval: 1.04-1.06).After adjustment for potential confounders, a higher prevalence of hypertension was observed in participants in the upper HSI quartiles (Q3 and Q4), with corresponding ORs of 2.29 (95% CI: 2.29-2.63) and 4.03 (95% CI: 3.42-4.74), respectively. RCS analysis revealed a U-shaped non-linear relationship between HSI and hypertension (P < 0.001), indicating that while hypertension risk primarily escalated with increasing HSI, a modest risk elevation was also detected at lower HSI levels. This suggests that both excessive liver fat accumulation (indicated by a high HSI) and underlying metabolic disorders (such as malnutrition or sarcopenia) may contribute to hypertension risk in individuals with unexpectedly low HSI. Subgroup analyses identified significant interactions in relation to education, cancer, and diabetes mellitus (p for interaction < 0.05), whereas no significant interactions were observed in other stratifications.

CONCLUSION

This study found a U-shaped relationship between the hepatic steatosis index (HSI) and the risk of hypertension. Although the HSI shows potential as a practical screening tool in primary care, further longitudinal studies are needed to establish causality and explore the complex bidirectional pathways involved.

CLINICAL TRIAL NUMBER

Not applicable.

The impact of oxidative stress on abnormal lipid metabolism-mediated disease development

Oxidative stress arises from an imbalance between cellular oxidation and anti-oxidation mechanisms, leading to various harmful effects on physiological health. These include inflammatory neutrophil infiltration, increased secretion of proteases, and increased production of oxidative intermediates, all of which significantly contribute to aging and the onset of multiple diseases. This review explores abnormal lipid metabolism, characterized by dysregulation in lipid synthesis, catabolism, digestion, absorption, and transport, with the potential to lead to lipid droplet accumulation or deficit across tissues, thus causing adverse health outcomes. Importantly, the intricate relationship between oxidative stress and inflammation plays a central role in exacerbating metabolic disorders, including diabetes, obesity, hypertension, non-alcoholic fatty liver disease, atherosclerosis, and lung fibrosis. This review seeks to compile and integrate recent research findings on the influence of oxidative stress on abnormal lipid metabolism pathology. A deeper understanding of this connection could reveal new perspectives for advancing the treatment and management of metabolic disorders.

Annexin A2 binds the 3'-UTR of H2AX mRNA and regulates histone-H2AX-derived hypoxia-inducible factor 1-alpha activation

Annexin A2 (Anxa2), a multifunctional protein with RNA-binding capabilities, is frequently overexpressed in various tumors, and its expression is highly correlated with malignant progression. In this study, we demonstrate for the first time that Anxa2 was co-expressed with glycolytic genes, suggesting its potential role as a regulator of glycolysis. RNA-protein interaction assay revealed that Anxa2 interacted with 3'-UTR of H2AX mRNA and protected it from miRNA-mediated degradation. Up-regulated Histone-H2AX enhances the expression of glycolytic genes including GLUT1, HK2, PGK1, ENO1, PKM2, GAPDH and LDHA via stabilizing hypoxia-inducible factor 1-alpha (HIF1α), thereby accelerating lactic acid production and secretion. (20S) G-Rh2, a natural compound targeting Anxa2, significantly interfered the Anxa2-H2AX mRNA interaction, and inhibited subsequent glycolysis progression. We propose that Anxa2 acts as a novel regulator in glycolysis via enhancing H2AX expression, and (20S) G-Rh2 may exert its anti-cancer activity by targeting Anxa2-H2AX-HIF1α-glycolysis axis in human hepatoma HepG2 cells.

Combined analysis of single-cell and bulk transcriptome sequencing data identifies critical glycolysis genes in idiopathic pulmonary arterial hypertension

BACKGROUND

Abnormal glycolytic metabolism plays a significant role in pulmonary vascular remodeling in idiopathic pulmonary arterial hypertension (IPAH), yet the specific mechanisms remain unclear. The primary objective of this study is to investigate the key regulatory mechanisms of glycolysis in IPAH.

METHODS

Bulk and single-cell sequencing data obtained from IPAH patient tissue samples were downloaded from the GEO database. scMetabolism and AUCcell analyses of the IPAH single-cell sequencing data were carried out to quantify the glycolytic metabolic activity and identify the main cell types regulating glycolysis, respectively. The ssGSEA method was used to assess the glycolytic activity in each bulk sample within the bulk sequencing data. Differential analysis, weighted gene co-expression network analysis (WGCNA), and protein-protein interaction (PPI) network analysis were conducted to identify key genes associated with glycolysis in IPAH samples. Single-cell sequencing and a monocrotaline (MCT)-induced model of PH in rats were utilized to validate the expression of these key genes.

RESULTS

Single-cell sequencing data indicated that IPAH patients displayed increased glycolytic activity, which was primarily regulated by fibroblasts. Similarly, bulk transcriptomic data revealed a significant increase in glycolytic activity in IPAH patients. Differential analysis, WGCNA, PPI network analysis, and integrated single-cell analysis further identified insulin-like growth factor-1 (IGF1), lysyl-tRNA synthetase (KARS), caspase-3 (CASP3), and cyclin-dependent kinase inhibitor 2 A (CDKN2A) as key genes associated with fibroblast-mediated glycolysis in IPAH patients. Differential expression of IGF1, KARS, CASP3, and CDKN2A was also observed in our in vivo model of PH.

CONCLUSION

Our study identifies IGF1, KARS, CASP3, and CDKN2A as key regulatory genes in glycolysis in IPAH, which provides the basis for the development of targeted therapies.

Death-associated protein kinase 1 prevents hypoxia-induced metabolic shift and pulmonary arterial smooth muscle cell proliferation in PAH

Pulmonary hypertension (PH) is a general term used to describe high blood pressure in the lungs from any cause. Pulmonary arterial hypertension (PAH) is a progressive, and fatal disease that causes the walls of the pulmonary arteries to tighten and stiffen. One of the major characteristics of PAH is the hyperproliferation and resistance to apoptosis of vascular cells, which trigger excessive pulmonary vascular remodeling and vasoconstriction. The death-associated protein DAP-kinase (DAPK) is a tumor suppressor and Ser/Thr protein kinase, which was previously shown to regulate the hypoxia inducible factor (HIF)-1α. Against this background, we now show that DAPK1 regulates human pulmonary arterial smooth muscle cell (hPASMC) proliferation and energy metabolism in a HIF-dependent manner. DAPK1 expression is downregulated in pulmonary vessels and PASMCs of human and experimental PH lungs. Reduced expression of DAPK1 in hypoxia and non-hypoxia PAH-PASMCs correlates with increased expression of HIF-1/2α. RNA interference-mediated depletion of DAPK1 leads to fundamental metabolic changes, including a significantly decreased rate of oxidative phosphorylation associated with enhanced expression of both HIF-1α and HIF-2α and glycolytic enzymes, as hexokinase 2 (HK2), lactate dehydrogenase A (LDHA), and an integrator between the glycolysis and citric acid cycle, pyruvate dehydrogenase kinase 1 (PDK1). DAPK1 ablation in healthy donor hPASMCs leads to an increase in proliferation, while its overexpression provides the opposite effects. Together our data indicate that DAPK1 serves as a new inhibitor of the pro-proliferative and glycolytic phenotype of PH in PASMCs acting via HIF-signaling pathway.

Enhanced lung endothelial glycolysis is implicated in the development of severe pulmonary hypertension in type 2 diabetes

Metabolic abnormalities in pulmonary endothelial cells are implicated in pulmonary hypertension (PH) while increasing evidence shows the influence of diabetes on progressing PH. In this study, we examined the effect of type 2 diabetes on hypoxia-induced PH and investigated its molecular mechanisms using hypoxia-induced diabetic male mice. Chronic hypoxia led to a more severe PH in type 2 diabetic mice than in control mice. Next, we compared gene expression patterns in isolated pulmonary endothelial cells (MPECs) from control mice in normoxia (CN), diabetic mice in normoxia (DN), control mice exposed to hypoxia (CH), and diabetic mice exposed to hypoxia (DH). The results showed that expression levels of 27 mRNAs, out of 92 mRNAs, were significantly different among the four groups. Two glycolysis-related proteins, GAPDH and HK2, were increased in MPECs of DH mice compared with those in DN or CH mice. In addition, the levels of pyruvate and lactate (glycolysis end products) were significantly increased in MPECs of DH mice, but not in CH mice, compared with MPECs of CN mice. Augmentation of glycolysis by terazosin exacerbated hypoxia-induced PH in CH mice but not in DH mice. On the contrary, inhibiting GAPDH (a key enzyme of the glycolytic pathway) by koningic acid ameliorated hypoxia-induced PH in DH mice but had no effect in CH mice. These data suggest that enhanced glycolysis in diabetic mice is involved in severe hypoxia-induced PH, and glycolysis inhibition is a potential target to reduce the severe progression of PH in patients with diabetes.NEW & NOTEWORTHY Increasing evidence shows that diabetes exacerbates the progression of pulmonary hypertension; however, its molecular mechanisms are understudied. In this study, we revealed that augmented glycolysis in diabetic pulmonary endothelial cells is involved in the development of severe PH in diabetes. Inhibition of glycolysis could be a therapeutic strategy for treating pulmonary hypertension in patients with diabetes.

Alterations in Mitochondrial Function in Pulmonary Vascular Diseases

Aims: Alterations of mitochondrial bioenergetics and arginine metabolism are universally present and mechanistically linked to pulmonary arterial hypertension (PAH), but there is little knowledge of arginine metabolism and mitochondrial functions across the different pulmonary hypertension (PH) groups. We hypothesize that abnormalities in mitochondrial functions are present across all PH groups and associated with clinical phenotypes. We test the hypothesis in PH patients and healthy controls from the Pulmonary Vascular Disease Phenomics Program cohort, who had comprehensive clinical phenotyping and follow-up for at least 4 years for death or transplant status. Mitochondrial transmembrane potential, superoxide production, and mass were measured by flow cytometry in fresh platelets. Metabolomics analysis was performed on plasma samples. Global arginine bioavailability was calculated as the ratio of arginine/(ornithine+citrulline). Results: Global arginine bioavailability is consistently lower than controls in all PH groups. Although the mitochondrial mass is similar across all PH groups and controls, superoxide production and transmembrane potential vary across groups. Mitochondrial superoxide is higher in group 1 PAH and lowest in group 3 compared with other groups, while transmembrane potential is lower in group 1 PAH than controls or group 3. The alterations in mitochondrial functions of group 1 PAH are associated with changes in fatty acid metabolism. Mitochondrial transmembrane potential in group 1 PAH is associated with transplant-free survival. Conclusion: While alterations in mitochondrial function are found in all PH groups, group 1 PAH has a unique mitochondrial phenotype with greater superoxide and lower transmembrane potential linked to fatty acid metabolism, and clinically to survival. Antioxid. Redox Signal. 42, 361-377.

Exploration of the metabolomic mechanisms of postmenopausal hypertension induced by low estrogen state

Estrogen significantly impacts women's health, and postmenopausal hypertension is a common issue characterized by blood pressure fluctuations. Current control strategies for this condition are limited in efficacy, necessitating further research into the underlying mechanisms. Although metabolomics has been applied to study various diseases, its use in understanding postmenopausal hypertension is scarce. Therefore, an ovariectomized rat model was used to simulate postmenopausal conditions. Estrogen levels, blood pressure, and aortic tissue metabolomics were analyzed. Animal models were divided into Sham, OVX, and OVX +E groups. Serum estrogen levels, blood pressure measurements, and aortic tissue metabolomics analyses were performed using radioimmunoassay, UHPLC-Q-TOF, and bioinformatics techniques. Based on the above research content, we successfully established a correlation between low estrogen levels and postmenopausal hypertension in rats. Notable differences in blood pressure parameters and aortic tissue metabolites were observed across the experimental groups. Specifically, metabolites that were differentially expressed, particularly L-alpha-aminobutyric acid (L-AABA), showed potential as a biomarker for postmenopausal hypertension, potentially exerting a protective function through macrophage activation and vascular remodeling. Enrichment analysis revealed alterations in sugar metabolism pathways, such as the Warburg effect and glycolysis, indicating their involvement in postmenopausal hypertension. Overall, this current research provides insights into the metabolic changes associated with postmenopausal hypertension, highlighting the role of L-AABA and sugar metabolism reprogramming in aortic tissue. The findings suggest a potential link between low estrogen levels, macrophage function, and vascular remodeling in the pathogenesis of postmenopausal hypertension. Further investigations are needed to validate these findings and explore their clinical implications for postmenopausal women.

Exercise improves systemic metabolism in a monocrotaline model of pulmonary hypertension

Exercise training in pulmonary arterial hypertension (PAH) has been gaining popularity with guidelines now recommending it as an important adjunct to medical therapy. Despite improvements in function and quality of life, an understanding of metabolic changes and their mechanisms remain unexplored. The objective of this study was therefore to understand the metabolic basis of exercise in a monocrotaline model of PAH. 24 male Wistar rats (age: 8-12 weeks and mean body weight: [262.16 ​± ​24.49] gms) were assigned to one of the four groups (i.e., Control, PAH, Exercise and PAH ​+ ​Exercise). The exercise groups participated in treadmill running at 13.3 ​m/min, five days a week for five weeks. Demographic and clinical characteristics were monitored regularly. Following the intervention, LC-MS based metabolomics were performed on blood samples from all groups at the end of five weeks. Metabolite profiling, peak identification, alignment and isotope annotation were also performed. Statistical inference was carried out using dimensionality reducing techniques and analysis of variance. Partial-least-squares discrimination analysis and variable importance in the projection scores showed that the model was reliable, and not over lifting. The analysis demonstrated significant perturbations to lipid and amino acid metabolism, arginine and homocysteine pathways, sphingolipid (p ​< ​0.05), glycerophospholipid (p ​< ​0.05) and nucleotide metabolism in PAH. Exercise, however, was seen to restore arginine (p ​< ​0.05) and homocysteine(p ​< ​0.000 1) levels which were independent effects, irrespective of PAH. Dysregulated arginine and homocysteine pathways are seen in PAH. Exercise restores these dysregulated pathways and could potentially impact severity and outcome in PAH.

Assessing the causality between pulmonary arterial hypertension and cancer: insights from Mendelian randomization

BACKGROUND

Previous clinical studies have suggested an increased risk of tumor development in patients with pulmonary arterial hypertension (PAH). However, it remains unclear whether there is a causal relationship between PAH and tumor occurrence. This study investigates the causal link between PAH and cancer from a genetic perspective using Mendelian randomization (MR).

METHOD

Genome-wide association study (GWAS) summary data for PAH and various common cancer types were obtained from the GWAS Catalog. Single nucleotide polymorphisms (SNPs) significantly associated with PAH at the genome-wide significance threshold (P < 1 × 10-6) were selected as instrumental variables (IVs). Inverse-variance weighted (IVW) was used as the primary method for MR analysis, with sensitivity analyses including tests for heterogeneity and horizontal pleiotropy.

RESULTS

The results from the IVW analysis indicate that genetically proxied PAH is associated with an increased risk of liver cancer [odd ratio (OR) 1.11, 95% confidence interval (CI) 1.01-1.22, P = 0.025), while showing no significant causal relationship with other common types of tumors (thyroid cancer: OR 0.95, 95% CI 0.86-1.06, P = 0.360; lung cancer: OR 0.95, 95% CI 0.90-1.01, P = 0.129; gastric cancer: OR 0.97, 95% CI 0.93-1.02, P = 0.243; colorectal cancer: OR 1.01, 95% CI 0.98-1.05, P = 0.412). Except for the MR analysis examining the causal effect of PAH on lung cancer (P = 0.049), the remaining MR analyses displayed no significant heterogeneity (P > 0.05). Additionally, the MR-Egger intercept test did not find evidence of horizontal pleiotropy (P > 0.05).

CONCLUSION

This study highlights that PAH may serve as a potential risk factor for this liver cancer. Future research should aim to elucidate the biological mechanisms at play and explore the potential for early interventions that could mitigate cancer risk in this vulnerable population.

SGLT2 inhibitors as a potential therapeutic option for pulmonary hypertension: mechanisms and clinical perspectives

Pulmonary arterial hypertension (PAH), one subtype of pulmonary hypertension (PH), is a life-threatening condition characterized by pulmonary arterial remodeling, elevated pulmonary vascular resistance, and blood pressure in the pulmonary arteries, leading to right heart failure and increased mortality. The disease is marked by endothelial dysfunction, vasoconstriction, and vascular remodeling. The role of Sodium-Glucose Co-Transporter-2 (SGLT2) inhibitors, a class of medications originally developed for diabetes management, is increasingly being explored in the context of cardiovascular diseases, including PAH, due to their potential to modulate these pathophysiological processes. In this review, we systematically examine the burgeoning evidence from both basic and clinical studies that describe the effects of SGLT2 inhibitors on cardiovascular health, with a special emphasis on PAH. By delving into the complex interactions between these drugs and the potential pathobiology that underpins PH, this study seeks to uncover the mechanistic underpinnings that could justify the use of SGLT2 inhibitors as a novel therapeutic approach for PAH. We collate findings that illustrate how SGLT2 inhibitors may influence the normal function of pulmonary arteries, possibly alleviating the pathological hallmarks of PAH such as inflammation, oxidative stress, aberrant cellular proliferation, and so on. Our review thereby outlines a potential paradigm shift in PAH management, suggesting that these inhibitors could play a crucial role in modulating the disease's progression by targeting the potential dysfunctions that drive it. This comprehensive synthesis of existing research underscores the imperative need for further clinical trials to validate the efficacy of SGLT2 inhibitors in PAH and to integrate them into the therapeutic agents used against this challenging disease.

Panorama of artery endothelial cell dysfunction in pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is a fatal lung disease characterized by progressive pulmonary vascular remodeling. The initial cause of pulmonary vascular remodeling is the dysfunction of pulmonary arterial endothelial cells (PAECs), manifested by changes in the categorization of cell subtypes, endothelial programmed cell death, such as apoptosis, necroptosis, pyroptosis, ferroptosis, et al., overproliferation, senescence, metabolic reprogramming, endothelial-to-mesenchymal transition, mechanosensitivity, and regulation ability of peripheral cells. Therefore, it is essential to explore the mechanism of endothelial dysfunction in the context of PAH. This review aims to provide a comprehensive understanding of the molecular mechanisms underlying endothelial dysfunction in PAH. We highlight the developmental process of PAECs and changes in PAH and summarise the latest classification of endothelial dysfunction. Our review could offer valuable insights into potential novel EC-specific targets for preventing and treating PAH.

Metabolic pathways, genomic alterations, and post-translational modifications in pulmonary hypertension and cancer as therapeutic targets and biomarkers

Background

Pulmonary hypertension (PH) can lead to right ventricular hypertrophy, significantly increasing mortality rates. This study aims to clarify PH-specific metabolites and their impact on genomic and post-translational modifications (PTMs) in cancer, evaluating DHA and EPA's therapeutic potential to mitigate oxidative stress and inflammation.

Methods

Data from 289,365 individuals were analyzed using Mendelian randomization to examine 1,400 metabolites' causal roles in PH. Anti-inflammatory and antioxidative effects of DHA and EPA were tested in RAW 264.7 macrophages and cancer cell lines (A549, HCT116, HepG2, LNCaP). Genomic features like CNVs, DNA methylation, tumor mutation burden (TMB), and PTMs were analyzed. DHA and EPA's effects on ROS production and cancer cell proliferation were assessed.

Results

We identified 57 metabolites associated with PH risk and examined key tumor-related pathways through promoter methylation analysis. DHA and EPA significantly reduced ROS levels and inflammatory markers in macrophages, inhibited the proliferation of various cancer cell lines, and decreased nuclear translocation of SUMOylated proteins during oxidative stress and inflammatory responses. These findings suggest a potential anticancer role through the modulation of stress-related nuclear signaling, as well as a regulatory function on cellular PTMs.

Conclusion

This study elucidates metabolic and PTM changes in PH and cancer, indicating DHA and EPA's role in reducing oxidative stress and inflammation. These findings support targeting these pathways for early biomarkers and therapies, potentially improving disease management and patient outcomes.

Unraveling the complex interplay between Mitochondria-Associated Membranes (MAMs) and cardiovascular Inflammation: Molecular mechanisms and therapeutic implications

Cardiovascular diseases (CVDs) represent a significant public health concern because of their associations with inflammation, oxidative stress, and abnormal remodeling of the heart and blood vessels. In this review, we discuss the intricate interplay between mitochondria-associated membranes (MAMs) and cardiovascular inflammation, highlighting their role in key cellular processes such as calcium homeostasis, lipid metabolism, oxidative stress management, and ERS. We explored how these functions impact the pathogenesis and progression of various CVDs, including myocardial ischemia-reperfusion injury, atherosclerosis, diabetic cardiomyopathy, cardiovascular aging, heart failure, and pulmonary hypertension. Additionally, we examined current therapeutic strategies targeting MAM-related pathways and proteins, emphasizing the potential of MAMs as therapeutic targets. Our review aims to provide new insights into the mechanisms of cardiovascular inflammation and propose novel therapeutic approaches to improve cardiovascular health outcomes.

PI3K p85α/HIF-1α accelerates the development of pulmonary arterial hypertension by regulating fatty acid uptake and mitophagy

BACKGROUND

Pulmonary arterial hypertension (PAH) is characterized by lipid accumulation and mitochondrial dysfunction. This study was designed to investigate the effects of hypoxia-inducible factor-1α (HIF-1α) on fatty acid uptake and mitophagy in PAH.

METHODS

Peripheral blood samples were obtained from PAH patients. Human pulmonary arterial smooth muscle cells and rat cardiac myoblasts H9c2 were subjected to hypoxia treatment. Male Sprague-Dawley rats were treated with monocrotaline (MCT). Right ventricular systolic pressure (RVSP), right ventricular hypertrophy index (RVHI), pulmonary artery remodeling, and lipid accumulation were measured. Cell proliferation and ROS accumulation were assessed. Mitochondrial damage and autophagosome formation were observed. Co-immunoprecipitation was performed to verify the interaction between HIF-1α and CD36/PI3K p85α.

RESULTS

HIF-1α, CD36, Parkin, and PINK1 were upregulated in PAH samples. HIF-1α knockdown or PI3K p85α knockdown restricted the expression of HIF-1α, PI3K p85α, Parkin, PINK1, and CD36, inhibited hPASMC proliferation, promoted H9c2 cell proliferation, reduced ROS accumulation, and suppressed mitophagy. CD36 knockdown showed opposite effects to HIF-1α knockdown, which were reversed by palmitic acid. The HIF-1α activator dimethyloxalylglycine reversed the inhibitory effect of Parkin knockdown on mitophagy. In MCT-induced rats, the HIF-1α antagonist 2-methoxyestradiol (2ME) reduced RVSP, RVHI, pulmonary artery remodeling, lipid accumulation, and mitophagy. Recombinant CD36 abolished the therapeutic effect of 2ME but inhibited mitophagy. Activation of Parkin/PINK1 by salidroside (Sal) promoted mitophagy to ameliorate the pathological features of PAH-like rats, and 2ME further enhanced the therapeutic outcome of Sal.

CONCLUSION

PI3K p85α/HIF-1α induced CD36-mediated fatty acid uptake and Parkin/PINK1-dependent mitophagy to accelerate the progression of experimental PAH.

Deciphering the inhibitory effects of trimetazidine on pulmonary hypertension development via decreasing fatty acid oxidation and promoting glucose oxidation

Pulmonary hypertension (PH) is a devastating disease characterized by vascular remodeling, resulting in right ventricular failure and death. Dysregulation of energy metabolism is linked to PH pathogenesis. Trimetazidine (TMZ), a selective long-chain 3-ketoacyl coenzyme A thiolase inhibitor, is critical in maintaining energy metabolism. Despite the indicated TMZ's inhibitory effect on pulmonary vascular remodeling in PH development, the integrated evaluation of the changes in biomolecules, such as metabolites and transcripts, that TMZ induces in the lung and heart tissues is largely unknown in vivo. For an improved understanding of the molecular mechanism involving the effects of TMZ on PH development, we performed a comprehensive analysis of the changes in cardiac metabolites and pulmonary transcripts of SU5416-Hypoxia (Su/Hx) rats treated with TMZ. Metabolomic analysis of the Su/Hx-induced PH hearts demonstrated that TMZ reduced the long-chain fatty acid concentration. Additionally, TMZ alleviated PH degree and excessive strain on the right heart functions in rats with Su/Hx-induced PH. We identified the candidate target genes for TMZ treatment during PH development. Interestingly, the mRNA levels of the fatty acid transporters were substantially downregulated by TMZ administration in the lungs with Su/Hx-induced PH. Notably, TMZ suppressed excessive proliferation of human pulmonary artery smooth muscle cells under hypoxic conditions. Our study suggests that TMZ ameliorates PH development by involving energy metabolism in the lungs and heart.

Mitochondria as a primary determinant of angiogenic modality in pulmonary arterial hypertension

Impaired pulmonary angiogenesis plays a pivotal role in the progression of pulmonary arterial hypertension (PAH) and patient mortality, yet the molecular mechanisms driving this process remain enigmatic. Our study uncovered a striking connection between mitochondrial dysfunction (MD), caused by a humanized mutation in the NFU1 gene, and severely disrupted pulmonary angiogenesis in adult lungs. Restoring the bioavailability of the NFU1 downstream target, lipoic acid (LA), alleviated MD and angiogenic deficiency and rescued the progressive PAH phenotype in the NFU1G206C model. Notably, significant NFU1 expression and signaling insufficiencies were also identified in idiopathic PAH (iPAH) patients' lungs, emphasizing this study's relevance beyond NFU1 mutation cases. The remarkable improvement in mitochondrial function of PAH patient-derived pulmonary artery endothelial cells (PAECs) following LA supplementation introduces LA as a potential therapeutic approach. In conclusion, this study unveils a novel role for MD in dysregulated pulmonary angiogenesis and PAH manifestation, emphasizing the need to correct MD in PAH patients with unrecognized NFU1/LA deficiency.

Metabolic Responses to Redox Stress in Vascular Cells

Significance: Redox stress underlies numerous vascular disease mechanisms. Metabolic adaptability is essential for vascular cells to preserve energy and redox homeostasis. Recent Advances: Single-cell technologies and multiomic studies demonstrate significant metabolic heterogeneity among vascular cells in health and disease. Increasing evidence shows that reductive or oxidative stress can induce metabolic reprogramming of vascular cells. A recent example is intracellular L-2-hydroxyglutarate accumulation in response to hypoxic reductive stress, which attenuates the glucose flux through glycolysis and mitochondrial respiration in pulmonary vascular cells and provides protection against further reductive stress. Critical Issues: Regulation of cellular redox homeostasis is highly compartmentalized and complex. Vascular cells rely on multiple metabolic pathways, but the precise connectivity among these pathways and their regulatory mechanisms is only partially defined. There is also a critical need to understand better the cross-regulatory mechanisms between the redox system and metabolic pathways as perturbations in either systems or their cross talk can be detrimental. Future Directions: Future studies are needed to define further how multiple metabolic pathways are wired in vascular cells individually and as a network of closely intertwined processes given that a perturbation in one metabolic compartment often affects others. There also needs to be a comprehensive understanding of how different types of redox perturbations are sensed by and regulate different cellular metabolic pathways with specific attention to subcellular compartmentalization. Lastly, integration of dynamic changes occurring in multiple metabolic pathways and their cross talk with the redox system is an important goal in this multiomics era. Antioxid. Redox Signal. 41,793-817.

Studying the Pulmonary Endothelium in Health and Disease: An Official American Thoracic Society Workshop Report

Lung endothelium resides at the interface between the circulation and the underlying tissue, where it senses biochemical and mechanical properties of both the blood as it flows through the vascular circuit and the vessel wall. The endothelium performs the bidirectional signaling between the blood and tissue compartments that is necessary to maintain homeostasis while physically separating both, facilitating a tightly regulated exchange of water, solutes, cells, and signals. Disruption in endothelial function contributes to vascular disease, which can manifest in discrete vascular locations along the artery-to-capillary-to-vein axis. Although our understanding of mechanisms that contribute to endothelial cell injury and repair in acute and chronic vascular disease have advanced, pathophysiological mechanisms that underlie site-specific vascular disease remain incompletely understood. In an effort to improve the translatability of mechanistic studies of the endothelium, the American Thoracic Society convened a workshop to optimize rigor, reproducibility, and translation of discovery to advance our understanding of endothelial cell function in health and disease.

5-Aminoimidazole-4-carboxamide ribonucleotide formyltransferase/inosine monophosphate cyclohydrolase promotes pulmonary arterial smooth muscle cell proliferation via the Ras signaling pathway

Pulmonary arterial hypertension (PAH) is a debilitating vascular disorder characterized by abnormal pulmonary artery smooth muscle cell (PASMC) proliferation and collagen synthesis, contributing to vascular remodeling and elevated pulmonary vascular resistance. This study investigated the critical role of 5-aminoimidazole-4-carboxamide ribonucleotide formyltransferase/inosine monophosphate cyclohydrolase (ATIC) in cell proliferation and collagen synthesis in PASMCs in PAH. Here we show that ATIC levels are significantly increased in the lungs of monocrotaline (MCT)-induced PAH rat model, hypoxia-induced PAH mouse model, and platelet-derived growth factor (PDGF)-stimulated PASMCs. Inhibition of ATIC attenuated PDGF-induced cell proliferation and collagen I synthesis in PASMCs. Conversely, overexpression or knockdown of ATIC causes a significant promotion or inhibition of Ras and ERK activation, cell proliferation, and collagen synthesis in PASMCs. Moreover, ATIC deficiency attenuated Ras activation in the lungs of hypoxia-induced PAH mice. Furthermore, Ras inhibition attenuates ATIC overexpression- and PDGF-induced collagen synthesis and PASMC proliferation. Notably, we identified that transcription factors MYC, early growth response protein 1 (EGR1), and specificity protein 1 (SP1) directly binds to promoters of Atic gene and regulate ATIC expression. These results provide the first evidence that ATIC promotes PASMC proliferation in pulmonary vascular remodeling through the Ras signaling pathway.NEW & NOTEWORTHY Our findings highlight the important role of ATIC in the PASMC proliferation of pulmonary vascular remodeling through its modulation of the Ras signaling pathway and its regulation by transcription factors MYC, EGR1, and SP1. ATIC's modulation of Ras signal pathway represents a novel mechanism contributing to PAH development.

Salidroside enhances NO bioavailability and modulates arginine metabolism to alleviate pulmonary arterial hypertension

BACKGROUND

Salidroside (SAL), derived from Rhodiola, shows protective effects in pulmonary arterial hypertension (PAH) models, but its mechanisms are not fully elucidated.

OBJECTIVES

Investigate the therapeutic effects and the mechanism of SAL on PAH.

METHODS

Monocrotaline was used to establish a PAH rat model. SAL's impact on oxidative stress and inflammatory responses in lung tissues was analyzed using immunohistochemistry, ELISA, and Western blot. Untargeted metabolomics explored SAL's metabolic regulatory mechanisms.

RESULTS

SAL significantly reduced mean pulmonary artery pressure, right ventricular hypertrophy, collagen deposition, and fibrosis in the PAH rats. It enhanced antioxidant enzyme levels, reduced inflammatory cytokines, and improved NO bioavailability by upregulating endothelial nitric oxide synthase (eNOS), soluble guanylate cyclase (sGC), cyclic guanosine monophosphate (cGMP), and protein kinase G (PKG) and decreases the expression of endothelin-1 (ET-1). Metabolomics indicated SAL restored metabolic balance in PAH rats, particularly in arginine metabolism.

CONCLUSIONS

SAL alleviates PAH by modulating arginine metabolism, enhancing NO synthesis, and improving pulmonary vascular remodeling.

Lactate dehydrogenase A (LDHA)-mediated lactate generation promotes pulmonary vascular remodeling in pulmonary hypertension

BACKGROUND

High levels of lactate are positively associated with prognosis and mortality in pulmonary hypertension (PH). Lactate dehydrogenase A (LDHA) is a key enzyme for the production of lactate. This study is undertaken to investigate the role and molecular mechanisms of lactate and LDHA in PH.

METHODS

Lactate levels were measured by a lactate assay kit. LDHA expression and localization were detected by western blot and Immunofluorescence. Proliferation and migration were determined by CCK8, western blot, EdU assay and scratch-wound assay. The right heart catheterization and right heart ultrasound were measured to evaluate cardiopulmonary function.

RESULTS

In vitro, we found that lactate promoted proliferation and migration of pulmonary artery smooth muscle cells (PASMCs) in an LDHA-dependent manner. In vivo, we found that LDHA knockdown reduced lactate overaccumulation in the lungs of mice exposed to hypoxia. Furthermore, LDHA knockdown ameliorated hypoxia-induced vascular remodeling and right ventricular dysfunction. In addition, the activation of Akt signaling by hypoxia was suppressed by LDHA knockdown both in vivo and in vitro. The overexpression of Akt reversed the inhibitory effect of LDHA knockdown on proliferation in PASMCs under hypoxia. Finally, LDHA inhibitor attenuated vascular remodeling and right ventricular dysfunction in Sugen/hypoxia mouse PH model, Monocrotaline (MCT)-induced rat PH model and chronic hypoxia-induced mouse PH model.

CONCLUSIONS

Thus, LDHA-mediated lactate production promotes pulmonary vascular remodeling in PH by activating Akt signaling pathway, suggesting the potential role of LDHA in regulating the metabolic reprogramming and vascular remodeling in PH.

Markuszewski M, Da̧browska-Kugacka A. Metabolomics Meets Clinics: A Multivariate Analysis of Plasma and Urine Metabolic Signatures in Pulmonary Arterial Hypertension

Pulmonary arterial hypertension (PAH) is a severe, multifactorial, and frequently misdiagnosed disorder. The aim of this observational study was to compare the plasma and urine metabolomic profiles of PAH patients and healthy control subjects. Plasma and urine metabolomic profiles were analyzed using the GC-MS technique. Correlations between metabolite levels and clinical parameters among PAH patients, as well as the between-group differences, were evaluated. The linear discriminant analysis model, which allows for subject classification in terms of PAH with the highest possible precision, was developed and proposed. Plasma pyruvic acid, cholesterol, threonine, urine 3-(3-hydroxyphenyl)-3-hydroxypropanoic acid, butyric acid, 1,2-benzenediol, glucoheptonic acid, and 2-oxo-glutaric acid were found to build a relatively accurate classification model for PAH patients. The model reached an accuracy of 91% and significantly improved subject classification (OR = 119 [95% CI: 20.3-698.3], p < 0.0001). Five metabolites were detected in urine that provide easily available and noninvasive tests as compared to right heart catheterization. The selected panel of metabolites has potential for early recognition of patients with dyspnea and faster referral to a reference center.

Exploring the pathogenesis of pulmonary vascular disease

Pulmonary hypertension (PH) is a complex cardiopulmonary disorder impacting the lung vasculature, resulting in increased pulmonary vascular resistance that leads to right ventricular dysfunction. Pulmonary hypertension comprises of 5 groups (PH group 1 to 5) where group 1 pulmonary arterial hypertension (PAH), results from alterations that directly affect the pulmonary arteries. Although PAH has a complex pathophysiology that is not completely understood, it is known to be a multifactorial disease that results from a combination of genetic, epigenetic and environmental factors, leading to a varied range of symptoms in PAH patients. PAH does not have a cure, its incidence and prevalence continue to increase every year, resulting in higher morbidity and mortality rates. In this review, we discuss the different pathologic mechanisms with a focus on epigenetic modifications and their roles in the development and progression of PAH. These modifications include DNA methylation, histone modifications, and microRNA dysregulation. Understanding these epigenetic modifications will improve our understanding of PAH and unveil novel therapeutic targets, thus steering research toward innovative treatment strategies.

SMYD2-Methylated PPARγ Facilitates Hypoxia-Induced Pulmonary Hypertension by Activating Mitophagy

BACKGROUND

Hyperproliferation of pulmonary arterial smooth muscle cells (PASMCs) and consequent pulmonary vascular remodeling are the crucial pathological features of pulmonary hypertension (PH). Protein methylation has been shown to be critically involved in PASMC proliferation and PH, but the underlying mechanism remains largely unknown.

METHODS

PH animal models were generated by treating mice/rats with chronic hypoxia for 4 weeks. SMYD2-vTg mice (vascular smooth muscle cell-specific suppressor of variegation, enhancer of zeste, trithorax and myeloid Nervy DEAF-1 (deformed epidural auto-regulatory factor-1) domain-containing protein 2 transgenic) or wild-type rats and mice treated with LLY-507 (3-cyano-5-{2-[4-[2-(3-methylindol-1-yl)ethyl]piperazin-1-yl]-phenyl}-N-[(3-pyrrolidin-1-yl)propyl]benzamide) were used to investigate the function of SMYD2 (suppressor of variegation, enhancer of zeste, trithorax and myeloid Nervy DEAF-1 domain-containing protein 2) on PH development in vivo. Primary cultured rat PASMCs with SMYD2 knockdown or overexpression were used to explore the effects of SMYD2 on proliferation and to decipher the underlying mechanism.

RESULTS

We demonstrated that the expression of the lysine methyltransferase SMYD2 was upregulated in the smooth muscle cells of pulmonary arteries from patients with PH and hypoxia-exposed rats/mice and in the cytoplasm of hypoxia-induced rat PASMCs. More importantly, targeted inhibition of SMYD2 by LLY-507 significantly attenuated hypoxia-induced pulmonary vascular remodeling and PH development in both male and female rats in vivo and reduced rat PASMC hyperproliferation in vitro. In contrast, SMYD2-vTg mice exhibited more severe PH phenotypes and related pathological changes than nontransgenic mice after 4 weeks of chronic hypoxia treatment. Furthermore, SMYD2 overexpression promoted, while SMYD2 knockdown suppressed, the proliferation of rat PASMCs by affecting the cell cycle checkpoint between S and G2 phases. Mechanistically, we revealed that SMYD2 directly interacted with and monomethylated PPARγ (peroxisome proliferator-activated receptor gamma) to inhibit the nuclear translocation and transcriptional activity of PPARγ, which further promoted mitophagy to facilitate PASMC proliferation and PH development. Furthermore, rosiglitazone, a PPARγ agonist, largely abolished the detrimental effects of SMYD2 overexpression on PASMC proliferation and PH.

CONCLUSIONS

Our results demonstrated that SMYD2 monomethylates nonhistone PPARγ and inhibits its nuclear translocation and activation to accelerate PASMC proliferation and PH by triggering mitophagy, indicating that targeting SMYD2 or activating PPARγ are potential strategies for the prevention of PH.

Metabolic changes contribute to maladaptive right ventricular hypertrophy in pulmonary hypertension beyond pressure overload: an integrative imaging and omics investigation

Right ventricular (RV) failure remains the strongest determinant of survival in pulmonary hypertension (PH). We aimed to identify relevant mechanisms, beyond pressure overload, associated with maladaptive RV hypertrophy in PH. To separate the effect of pressure overload from other potential mechanisms, we developed in pigs two experimental models of PH (M1, by pulmonary vein banding and M2, by aorto-pulmonary shunting) and compared them with a model of pure pressure overload (M3, pulmonary artery banding) and a sham-operated group. Animals were assessed at 1 and 8 months by right heart catheterization, cardiac magnetic resonance and blood sampling, and myocardial tissue was analyzed. Plasma unbiased proteomic and metabolomic data were compared among groups and integrated by an interaction network analysis. A total of 33 pigs completed follow-up (M1, n = 8; M2, n = 6; M3, n = 10; and M0, n = 9). M1 and M2 animals developed PH and reduced RV systolic function, whereas animals in M3 showed increased RV systolic pressure but maintained normal function. Significant plasma arginine and histidine deficiency and complement system activation were observed in both PH models (M1&M2), with additional alterations to taurine and purine pathways in M2. Changes in lipid metabolism were very remarkable, particularly the elevation of free fatty acids in M2. In the integrative analysis, arginine-histidine-purines deficiency, complement activation, and fatty acid accumulation were significantly associated with maladaptive RV hypertrophy. Our study integrating imaging and omics in large-animal experimental models demonstrates that, beyond pressure overload, metabolic alterations play a relevant role in RV dysfunction in PH.

Pulmonary Hypertension and Hyperglycemia-Not a Sweet Combination

Hyperglycemia and pulmonary hypertension (PH) share common pathological pathways that lead to vascular dysfunction and resultant cardiovascular complications. These shared pathologic pathways involve endothelial dysfunction, inflammation, oxidative stress, and hormonal imbalances. Individuals with hyperglycemia or pulmonary hypertension also possess shared clinical factors that contribute to increased morbidity from both diseases. This review aims to explore the relationship between PH and hyperglycemia, highlighting the mechanisms underlying their association and discussing the clinical implications. Understanding these common pathologic and clinical factors will enable early detection for those at-risk for complications from both diseases, paving the way for improved research and targeted therapeutics.

Bawei Chenxiang Wan ameliorates right ventricular hypertrophy in rats with high altitude heart disease by SIRT3-HIF1α-PDK/PDH signaling pathway improving fatty acid and glucose metabolism

BACKGROUND

Bawei Chenxiang Wan (BCW) is among the most effective and widely used therapies for coronary heart disease and angina pectoris in Tibet. However, whether it confers protection through a right-ventricle (RV) myocardial metabolic mechanism is unknown.

METHODS

Male Sprague-Dawley rats were orally administrated with BCW, which was injected concurrently with a bolus of Sugen5416, and subjected to hypoxia exposure (SuHx; 5000 m altitude) for 4 weeks. Right ventricular hypertrophy (RVH) in high-altitude heart disease (HAHD) was assessed using Fulton's index (FI; ratio of RV to left ventricle + septum weights) and heart-weight-to-body-weight ratio (HW/BW). The effect of therapeutic administration of BCW on the RVH hemodynamics was assessed through catheterization (mean right ventricular pressure and mean pulmonary artery pressure (mRVP and mPAP, respectively)). Tissue samples were used to perform histological staining, and confirmatory analyses of mRNA and protein levels were conducted to detect alterations in the mechanisms of RVH in HAHD. The protective mechanism of BCW was further verified via cell culture.

RESULTS

BCW considerably reduced SuHx-associated RVH, as indicated by macro morphology, HW/BW ratio, FI, mPAP, mRVP, hypertrophy markers, heart function, pathological structure, and myocardial enzymes. Moreover, BCW can alleviate the disorder of glucose and fatty acid metabolism through upregulation of carnitine palmitoyltransferase1ɑ, citrate synthase, and acetyl-CoA and downregulation of glucose transport-4, phosphofructokinase, and pyruvate, which resulted in the reduced levels of free fatty acid and lactic acid and increased aerobic oxidation. This process may be mediated via the regulation of sirtuin 3 (SIRT3)-hypoxia-inducible factor 1α (HIF1α)-pyruvate dehydrogenase kinase (PDK)/pyruvate dehydrogenase (PDH) signaling pathway. Subsequently, the inhibition of SIRT3 expression by 3-TYP (a selective inhibitor of SIRT3) can reverse substantially the anti-RVH effect of BCW in HAHD, as indicated by hypertrophy marker and serum myocardial enzyme levels.

CONCLUSIONS

BCW prevented SuHx-induced RVH in HAHD via the SIRT3-HIF1ɑ-PDK/PDH signaling pathway to alleviate the disturbance in fatty acid and glucose metabolism. Therefore, BCW can be used as an alternative drug for the treatment of RVH in HAHD.

Functions and novel regulatory mechanisms of key glycolytic enzymes in pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is a progressive vascular disease characterized by remodeling of the pulmonary vasculature and elevated pulmonary arterial pressure, ultimately leading to right heart failure and death. Despite its clinical significance, the precise molecular mechanisms driving PAH pathogenesis warrant confirmation. Compelling evidence indicates that during the development of PAH, pulmonary vascular cells exhibit a preference for energy generation through aerobic glycolysis, known as the "Warburg effect", even in well-oxygenated conditions. This metabolic shift results in imbalanced metabolism, increased proliferation, and severe pulmonary vascular remodeling. Exploring the Warburg effect and its interplay with glycolytic enzymes in the context of PAH has yielded current insights into emerging drug candidates targeting enzymes and intermediates involved in glucose metabolism. This sheds light on both opportunities and challenges in the realm of antiglycolytic therapy for PAH.

Inactivation of Malic Enzyme 1 in Endothelial Cells Alleviates Pulmonary Hypertension

BACKGROUND

Pulmonary hypertension (PH) is a progressive cardiopulmonary disease with a high mortality rate. Although growing evidence has revealed the importance of dysregulated energetic metabolism in the pathogenesis of PH, the underlying cellular and molecular mechanisms are not fully understood. In this study, we focused on ME1 (malic enzyme 1), a key enzyme linking glycolysis to the tricarboxylic acid cycle. We aimed to determine the role and mechanistic action of ME1 in PH.

METHODS

Global and endothelial-specific ME1 knockout mice were used to investigate the role of ME1 in hypoxia- and SU5416/hypoxia (SuHx)-induced PH. Small hairpin RNA and ME1 enzymatic inhibitor (ME1*) were used to study the mechanism of ME1 in pulmonary artery endothelial cells. Downstream key metabolic pathways and mediators of ME1 were identified by metabolomics analysis in vivo and ME1-mediated energetic alterations were examined by Seahorse metabolic analysis in vitro. The pharmacological effect of ME1* on PH treatment was evaluated in PH animal models induced by SuHx.

RESULTS

We found that ME1 protein level and enzymatic activity were highly elevated in lung tissues of patients and mice with PH, primarily in vascular endothelial cells. Global knockout of ME1 protected mice from developing hypoxia- or SuHx-induced PH. Endothelial-specific ME1 deletion similarly attenuated pulmonary vascular remodeling and PH development in mice, suggesting a critical role of endothelial ME1 in PH. Mechanistic studies revealed that ME1 inhibition promoted downstream adenosine production and activated A2AR-mediated adenosine signaling, which leads to an increase in nitric oxide generation and a decrease in proinflammatory molecule expression in endothelial cells. ME1 inhibition activated adenosine production in an ATP-dependent manner through regulating malate-aspartate NADH (nicotinamide adenine dinucleotide plus hydrogen) shuttle and thereby balancing oxidative phosphorylation and glycolysis. Pharmacological inactivation of ME1 attenuated the progression of PH in both preventive and therapeutic settings by promoting adenosine production in vivo.

CONCLUSIONS

Our findings indicate that ME1 upregulation in endothelial cells plays a causative role in PH development by negatively regulating adenosine production and subsequently dysregulating endothelial functions. Our findings also suggest that ME1 may represent as a novel pharmacological target for upregulating protective adenosine signaling in PH therapy.

A perfectly imperfect engine: Utilizing the digital twin paradigm in pulmonary hypertension

Pulmonary hypertension (PH) is a severe medical condition with a number of treatment options, the majority of which are introduced without consideration of the underlying mechanisms driving it within an individual and thus a lack of tailored approach to treatment. The one exception is a patient presenting with apparent pulmonary arterial hypertension and shown to have vaso-responsive disease, whose clinical course and prognosis is significantly improved by high dose calcium channel blockers. PH is however characterized by a relative abundance of available data from patient cohorts, ranging from molecular data characterizing gene and protein expression in different tissues to physiological data at the organ level and clinical information. Integrating available data with mechanistic information at the different scales into computational models suggests an approach to a more personalized treatment of the disease using model-based optimization of interventions for individual patients. That is, constructing digital twins of the disease, customized to a patient, promises to be a key technology for personalized medicine, with the aim of optimizing use of existing treatments and developing novel interventions, such as new drugs. This article presents a perspective on this approach in the context of a review of existing computational models for different aspects of the disease, and it lays out a roadmap for a path to realizing it.

Reduction in activity and abundance of mitochondrial electron transport chain supercomplexes in pulmonary hypertension-induced right ventricular dysfunction

Pulmonary hypertension (PH) results in RV hypertrophy, fibrosis and dysfunction resulting in RV failure which is associated with impaired RV metabolism and mitochondrial respiration. Mitochondrial supercomplexes (mSC) are assemblies of multiple electron transport chain (ETC) complexes that consist of physically associated complex I, III and IV that may enhance respiration and lower ROS generation. The goal of this study was to determine if mSCs are reduced in RV dysfunction associated with PH. We induced PH in Sprague-Dawley rats by Sugen/Hypoxia (3 weeks) followed by normoxia (4 weeks). Control and PH rats were subjected to echocardiography, blue and clear native-PAGE to assess mSC abundance and activity, and cardiomyocyte isolation to assess mitochondrial reactive oxygen species (ROS). mSC formation was also assessed in explanted human hearts with and without RV dysfunction. RV activity of CI and CIV and abundance of CI, CIII and CIV in mitochondrial mSCs was severely reduced in PH rats compared to control. There were no differences in total CI or CIV activity or abundance in smaller ETC assemblies. There were no changes in both RV and LV of expression of representative ETC complex subunits. PAT, TAPSE and RV Wall thickness significantly correlated with CIV and CI activity in mSC, but not total CI and CIV activity in the RV. Consistent with reduced mSC activity, isolated PH RV myocytes had increased mitochondrial ROS generation compared to control. Reduced mSC activity was also demonstrated in explanted human RV tissue from patients undergoing cardiac transplant with RV dysfunction. The right atrial pressure/pulmonary capillary wedge pressure ratio (RAP/PCWP, an indicator of RV dysfunction) negatively correlated with RV mSC activity level. In conclusion, reduced assembly and activity of mitochondrial mSC is correlated with RV dysfunction in PH rats and humans with RV dysfunction.

Hub gene ELK3-mediated reprogramming lipid metabolism regulates phenotypic switching of pulmonary artery smooth muscle cells to develop pulmonary arterial hypertension induced by PM2.5

Fine particulate matter (PM2.5) as an environmental pollutant is related with respiratory and cardiovascular diseases. Pulmonary arterial hypertension (PAH) was characterized by incremental pulmonary artery pressure and pulmonary arterial remodeling, leading to right ventricular hypertrophy, and finally cardiac failure and death. The adverse effects on pulmonary artery and the molecular biological mechanism underlying PM2.5-caused PAH has not been elaborated clearly. In the current study, the ambient PM2.5 exposure mice model along with HPASMCs models were established. Based on bioinformatic methods and machine learning algorithms, the hub genes in PAH were screened and then adverse effects on pulmonary artery and potential mechanism was studied. Our results showed that chronic PM2.5 exposure contributed to increased pulmonary artery pressure, pulmonary arterial remodeling and right ventricular hypertrophy in mice. In vitro, PM2.5 induced phenotypic switching in HPASMCs, which served as the early stage of PAH. In mechanism, we investigated that PM2.5-mediated mitochondrial dysfunction could induce phenotypic switching in HPASMCs, which was possibly through reprogramming lipid metabolism. Next, we used machine learning algorithm to identify ELK3 as potential hub gene for mitochondrial fission. Besides, the effect of DNA methylation on ELK3 was further detected in HPASMCs after PM2.5 exposure. The results provided novel directions for protection of pulmonary vasculature injury, against adverse environmental stimuli. This work also provided a new idea for the prevention of PAH, as well as provided experimental evidence for the targeted therapy of PAH.

Extrapulmonary manifestations of pulmonary arterial hypertension

INTRODUCTION

Extrapulmonary manifestations of pulmonary arterial hypertension (PAH) may play a critical pathobiological role and a deeper understanding will advance insight into mechanisms and novel therapeutic targets. This manuscript reviews our understanding of extrapulmonary manifestations of PAH.

AREAS COVERED

A group of experts was assembled and a complimentary PubMed search performed (October 2023 - March 2024). Inflammation is observed throughout the central nervous system and attempts at manipulation are an encouraging step toward novel therapeutics. Retinal vascular imaging holds promise as a noninvasive method of detecting early disease and monitoring treatment responses. PAH patients have gut flora alterations and dysbiosis likely plays a role in systemic inflammation. Despite inconsistent observations, the roles of obesity, insulin resistance and dysregulated metabolism may be illuminated by deep phenotyping of body composition. Skeletal muscle dysfunction is perpetuated by metabolic dysfunction, inflammation, and hypoperfusion, but exercise training shows benefit. Renal, hepatic, and bone marrow abnormalities are observed in PAH and may represent both end-organ damage and disease modifiers.

EXPERT OPINION

Insights into systemic manifestations of PAH will illuminate disease mechanisms and novel therapeutic targets. Additional study is needed to understand whether extrapulmonary manifestations are a cause or effect of PAH and how manipulation may affect outcomes.

Blockade of ZFX Alleviates Hypoxia-Induced Pulmonary Vascular Remodeling by Regulating the YAP Signaling

High expression of the zinc finger X-chromosomal protein (ZFX) correlates with proliferation, aggressiveness, and development in many types of cancers. In the current report, we investigated the efficacy of ZFX in mouse pulmonary artery smooth muscle cells (PASMCs) proliferation during pulmonary arterial hypertension (PAH). PASMCs were cultured in hypoxic conditions. Real-time PCR and western blotting were conducted to detect the expression of ZFX. Cell proliferation, apoptosis, migration, and invasion were, respectively, measured by CCK-8, flow cytometry, wound scratchy, and transwell assays. Glycolytic ability was validated by the extracellular acidification rate and oxygen consumption rate. Transcriptome sequencing technology was used to explore the genes affected by ZFX knockdown. Luciferase and chromatin immunoprecipitation assays were utilized to verify the possible binding site of ZFX and YAP1. Mice were subjected to hypoxia for 21 days to induce PAH. The right ventricular systolic pressure (RVSP) was measured and ratio of RV/LV + S was calculated. The results show that ZFX was increased in hypoxia-induced PASMCs and mice. ZFX knockdown inhibited the proliferation, migration, and invasion of PASMC. Using RNA sequencing, we identify glycolysis and YAP as a key signaling of ZFX. ZFX knockdown inhibited Glycolytic ability. ZFX strengthened the transcription activity of YAP1, thereby regulating the YAP signaling. YAP1 overexpression reversed the effect of ZFX knockdown on hypoxia-treated PASMCs. In conclusion, ZFX knockdown protected mice from hypoxia-induced PAH injury. ZFX knockdown dramatically reduced RVSP and RV/(LV + S) in hypoxia-treated mice.

Amino acid profiles: exploring their diagnostic and pathophysiological significance in hypertension

Hypertension, a major contributor to cardiovascular morbidity, is closely linked to amino acid metabolism. Amino acids, particularly branched-chain amino acids (BCAAs) and aromatic amino acids (AAAs), may play pivotal roles in the pathogenesis and potential management of hypertension. This review investigated the relationships between amino acid profiles, specifically BCAAs and AAAs, and hypertension, and examined their potential as diagnostic and therapeutic targets. An in-depth analysis was conducted on studies highlighting the associations of specific amino acids such as arginine, glycine, proline, glutamine, and the BCAAs and AAAs with hypertension. BCAAs and AAAs, alongside other amino acids like arginine, glycine, and proline, showed significant correlations with hypertension. These amino acids influence multiple pathways including nitric oxide synthesis, vascular remodeling, and neurotransmitter production, among others. Distinct amino acid profiles were discerned between hypertensive and non-hypertensive individuals. Amino acid profiling, particularly the levels of BCAAs and AAAs, offers promising avenues in the diagnostic and therapeutic strategies for hypertension. Future studies are crucial to confirm these findings and to delineate amino acid-based interventions for hypertension treatment.

Real-Time Exposure to 3D-Printing Emissions Elicits Metabolic and Pro-Inflammatory Responses in Human Airway Epithelial Cells

Three-dimensional (3D) printer usage in household and school settings has raised health concerns regarding chemical and particle emission exposures during operation. Although the composition of 3D printer emissions varies depending on printer settings and materials, little is known about the impact that emissions from different filament types may have on respiratory health and underlying cellular mechanisms. In this study, we used an in vitro exposure chamber system to deliver emissions from two popular 3D-printing filament types, acrylonitrile butadiene styrene (ABS) and polylactic acid (PLA), directly to human small airway epithelial cells (SAEC) cultured in an air-liquid interface during 3D printer operation. Using a scanning mobility particle sizer (SMPS) and an optical particle sizer (OPS), we monitored 3D printer particulate matter (PM) emissions in terms of their particle size distribution, concentrations, and calculated deposited doses. Elemental composition of ABS and PLA emissions was assessed using scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM-EDX). Finally, we compared the effects of emission exposure on cell viability, inflammation, and metabolism in SAEC. Our results reveal that, although ABS filaments emitted a higher total concentration of particles and PLA filaments emitted a higher concentration of smaller particles, SAEC were exposed to similar deposited doses of particles for each filament type. Conversely, ABS and PLA emissions had distinct elemental compositions, which were likely responsible for differential effects on SAEC viability, oxidative stress, release of inflammatory mediators, and changes in cellular metabolism. Specifically, while ABS- and PLA-emitted particles both reduced cellular viability and total glutathione levels in SAEC, ABS emissions had a significantly greater effect on glutathione relative to PLA emissions. Additionally, pro-inflammatory cytokines including IL-1β, MMP-9, and RANTES were significantly increased due to ABS emissions exposure. While IL-6 and IL-8 were stimulated in both exposure scenarios, VEGF was exclusively increased due to PLA emissions exposures. Notably, ABS emissions induced metabolic perturbation on amino acids and energy metabolism, as well as redox-regulated pathways including arginine, methionine, cysteine, and vitamin B3 metabolism, whereas PLA emissions exposures caused fatty acid and carnitine dysregulation. Taken together, these results advance our mechanistic understanding of 3D-printer-emissions-induced respiratory toxicity and highlight the role that filament emission properties may play in mediating different respiratory outcomes.

Expression and regulation of HIF-1a in hypoxic pulmonary hypertension: Focus on pathological mechanism and Pharmacological Treatment

Hypoxia inducible factor-1(HIF-1), a heterodimeric transcription factor, is composed of two subunits (HIF-1α and HIF-1β). It is considered as an important transcription factor for regulating oxygen changes in hypoxic environment, which can regulate the expression of various hypoxia-related target genes and play a role in acute and chronic hypoxia pulmonary vascular reactions. In this paper, the function and mechanism of HIF-1a expression and regulation in hypoxic pulmonary hypertension (HPH) were reviewed, and current candidate schemes for treating pulmonary hypertension by using HIF-1a as the target were introduced, so as to provide reference for studying the pathogenesis of HPH and screening effective treatment methods.

Celastrol ameliorates energy metabolism dysfunction of hypertensive rats by dilating vessels to improve hemodynamics

The impact of hypertension on tissue and organ damage is mediated through its influence on the structure and function of blood vessels. This study aimed to examine the potential of celastrol, a bioactive compound derived from Tripterygium wilfordii Hook F, in mitigating hypertension-induced energy metabolism disorder and enhancing blood perfusion and vasodilation. In order to investigate this phenomenon, we conducted in vivo experiments on renovascular hypertensive rats, employing indirect calorimetry to measure energy metabolism and laser speckle contrast imaging to evaluate hemodynamics. In vitro, we assessed the vasodilatory effects of celastrol on the basilar artery and superior mesenteric artery of rats using the Multi Wires Myograph System. Furthermore, we conducted preliminary investigations to elucidate the underlying mechanism. Moreover, administration of celastrol at doses of 1 and 2 mg/kg yielded a notable enhancement in blood flow ranging from 6 to 31% across different cerebral and mesenteric vessels in hypertensive rats. Furthermore, celastrol demonstrated a concentration-dependent (1 × 10-7 to 1 × 10-5 M) arterial dilation, independent of endothelial function. This vasodilatory effect could potentially be attributed to the inhibition of Ca2+ channels on vascular smooth muscle cells induced by celastrol. These findings imply that celastrol has the potential to ameliorate hemodynamics through vasodilation, thereby alleviating energy metabolism dysfunctions in hypertensive rats. Consequently, celastrol may hold promise as a novel therapeutic agent for the treatment of hypertension.

Pulmonary arterial hypertension nanotherapeutics: New pharmacological targets and drug delivery strategies

Pulmonary arterial hypertension (PAH) is a rare, serious, and incurable disease characterized by high lung pressure. PAH-approved drugs based on conventional pathways are still not exhibiting favorable therapeutic outcomes. Drawbacks like short half-lives, toxicity, and teratogenicity hamper effectiveness, clinical conventionality, and long-term safety. Hence, approaches like repurposing drugs targeting various and new pharmacological cascades and/or loaded in non-toxic/efficient nanocarrier systems are being investigated lately. This review summarizes the status of conventional, repurposed, either in vitro, in vivo, and/or in clinical trials of PAH treatment. In-depth description, discussion, and classification of the new pharmacological targets and nanomedicine strategies with a description of all the nanocarriers that showed promising efficiency in delivering drugs are discussed. Ultimately, an illustration of the different nucleic acids tailored and nanoencapsulated within different types of nanocarriers to restore the pathways affected by this disease is presented.

Transcriptional profiles of pulmonary artery endothelial cells in pulmonary hypertension

Pulmonary arterial hypertension (PAH) is characterized by endothelial cell (EC) dysfunction. There are no data from living patients to inform whether differential gene expression of pulmonary artery ECs (PAECs) can discern disease subtypes, progression and pathogenesis. We aimed to further validate our previously described method to propagate ECs from right heart catheter (RHC) balloon tips and to perform additional PAEC phenotyping. We performed bulk RNA sequencing of PAECs from RHC balloons. Using unsupervised dimensionality reduction and clustering we compared transcriptional signatures from PAH to controls and other forms of pulmonary hypertension. Select PAEC samples underwent single cell and population growth characterization and anoikis quantification. Fifty-four specimens were analyzed from 49 subjects. The transcriptome appeared stable over limited passages. Six genes involved in sex steroid signaling, metabolism, and oncogenesis were significantly upregulated in PAH subjects as compared to controls. Genes regulating BMP and Wnt signaling, oxidative stress and cellular metabolism were differentially expressed in PAH subjects. Changes in gene expression tracked with clinical events in PAH subjects with serial samples over time. Functional assays demonstrated enhanced replication competency and anoikis resistance. Our findings recapitulate fundamental biological processes of PAH and provide new evidence of a cancer-like phenotype in ECs from the central vasculature of PAH patients. This "cell biopsy" method may provide insight into patient and lung EC heterogeneity to advance precision medicine approaches in PAH.

Novel Relationship between Mitofusin 2-Mediated Mitochondrial Hyperfusion, Metabolic Remodeling, and Glycolysis in Pulmonary Arterial Endothelial Cells

The disruption of mitochondrial dynamics has been identified in cardiovascular diseases, including pulmonary hypertension (PH), ischemia-reperfusion injury, heart failure, and cardiomyopathy. Mitofusin 2 (Mfn2) is abundantly expressed in heart and pulmonary vasculature cells at the outer mitochondrial membrane to modulate fusion. Previously, we have reported reduced levels of Mfn2 and fragmented mitochondria in pulmonary arterial endothelial cells (PAECs) isolated from a sheep model of PH induced by pulmonary over-circulation and restoring Mfn2 normalized mitochondrial function. In this study, we assessed the effect of increased expression of Mfn2 on mitochondrial metabolism, bioenergetics, reactive oxygen species production, and mitochondrial membrane potential in control PAECs. Using an adenoviral expression system to overexpress Mfn2 in PAECs and utilizing 13C labeled substrates, we assessed the levels of TCA cycle metabolites. We identified increased pyruvate and lactate production in cells, revealing a glycolytic phenotype (Warburg phenotype). Mfn2 overexpression decreased the mitochondrial ATP production rate, increased the rate of glycolytic ATP production, and disrupted mitochondrial bioenergetics. The increase in glycolysis was linked to increased hypoxia-inducible factor 1α (HIF-1α) protein levels, elevated mitochondrial reactive oxygen species (mt-ROS), and decreased mitochondrial membrane potential. Our data suggest that disrupting the mitochondrial fusion/fission balance to favor hyperfusion leads to a metabolic shift that promotes aerobic glycolysis. Thus, therapies designed to increase mitochondrial fusion should be approached with caution.

Cyclin D-CDK4 Disulfide Bond Attenuates Pulmonary Vascular Cell Proliferation

BACKGROUND

Pulmonary hypertension (PH) is a chronic vascular disease characterized, among other abnormalities, by hyperproliferative smooth muscle cells and a perturbed cellular redox and metabolic balance. Oxidants induce cell cycle arrest to halt proliferation; however, little is known about the redox-regulated effector proteins that mediate these processes. Here, we report a novel kinase-inhibitory disulfide bond in cyclin D-CDK4 (cyclin-dependent kinase 4) and investigate its role in cell proliferation and PH.

METHODS

Oxidative modifications of cyclin D-CDK4 were detected in human pulmonary arterial smooth muscle cells and human pulmonary arterial endothelial cells. Site-directed mutagenesis, tandem mass-spectrometry, cell-based experiments, in vitro kinase activity assays, in silico structural modeling, and a novel redox-dead constitutive knock-in mouse were utilized to investigate the nature and definitively establish the importance of CDK4 cysteine modification in pulmonary vascular cell proliferation. Furthermore, the cyclin D-CDK4 oxidation was assessed in vivo in the pulmonary arteries and isolated human pulmonary arterial smooth muscle cells of patients with pulmonary arterial hypertension and in 3 preclinical models of PH.

RESULTS

Cyclin D-CDK4 forms a reversible oxidant-induced heterodimeric disulfide dimer between C7/8 and C135, respectively, in cells in vitro and in pulmonary arteries in vivo to inhibit cyclin D-CDK4 kinase activity, decrease Rb (retinoblastoma) protein phosphorylation, and induce cell cycle arrest. Mutation of CDK4 C135 causes a kinase-impaired phenotype, which decreases cell proliferation rate and alleviates disease phenotype in an experimental mouse PH model, suggesting this cysteine is indispensable for cyclin D-CDK4 kinase activity. Pulmonary arteries and human pulmonary arterial smooth muscle cells from patients with pulmonary arterial hypertension display a decreased level of CDK4 disulfide, consistent with CDK4 being hyperactive in human pulmonary arterial hypertension. Furthermore, auranofin treatment, which induces the cyclin D-CDK4 disulfide, attenuates disease severity in experimental PH models by mitigating pulmonary vascular remodeling.

CONCLUSIONS

A novel disulfide bond in cyclin D-CDK4 acts as a rapid switch to inhibit kinase activity and halt cell proliferation. This oxidative modification forms at a critical cysteine residue, which is unique to CDK4, offering the potential for the design of a selective covalent inhibitor predicted to be beneficial in PH.

Short-term study of atrial shunt and improvement of functional mitral regurgitation

BACKGROUND

This study used an atrial septal shunt to compare the treatment progress and prognosis for patients with heart failure (HF) who have different ejection fractions.

METHODS

Twenty HF patients with pulmonary hypertension, who required atrial septal shunt therapy, were included in this study. The patients underwent surgery between December 2012 and December 2020. They were divided into two groups based on their ejection fraction: a group with reduced ejection fraction (HFrEF) and a group with preserved ejection fraction(HFpEF) + mid-range ejection fraction (HfmrEF). Echocardiography was utilized to evaluate parameters such as left ventricular dimension (LVD), left ventricular ejection fraction (LVEF), and left ventricular end-diastolic volume (LVEDV). Hemodynamic parameters were measured using cardiac catheterization. The patient's cardiac function was assessed using the six-minute walking test (6MWT), KCCQ score, NYHA classification, and the degree of functional mitral regurgitation (FMR). Followed-up visits were conducted at 1, 3, and 6 months, and any adverse effects were recorded.

RESULTS

The LVEF values were consistently higher in the HFpEF+HFmrEF group than HFrEF group at all periods (P < 0.05). Differences in LVD were observed between the two groups before the surgery. Statistically, significant differences were found at the preoperative stage, 1 month, and 3 months (P < 0.05, respectively). However, the LVEDV showed a significant difference between the two groups only at 3 months (P = 0.049). Notably, there were notable variations in LAPm, LAPs, and the pressure gradient between the LA-RA gradient at baeline, after implantation, and during the 6 months follow-up (all P < 0.05).

CONCLUSION

Following treatment, the HFpEF+HFmrEF group exhibited more significant improvements in echocardiographic and cardiac catheterization indices than the HFrEF group. However, there was no statistically significant difference between the two groups regarding the 6MWT and KCCQ scores. It is important to note that the findings of this study still require further investigation in a large sample size of patients.

SIRT3 Is a Critical Regulator of Mitochondrial Function of Fibroblasts in Pulmonary Hypertension

Pulmonary hypertension (PH) is a heterogeneous and life-threatening cardiopulmonary disorder in which mitochondrial dysfunction is believed to drive pathogenesis, although the underlying mechanisms remain unclear. To determine if abnormal SIRT3 (sirtuin 3) activity is related to mitochondrial dysfunction in adventitial fibroblasts from patients with idiopathic pulmonary arterial hypertension (IPAH) and hypoxic PH calves (PH-Fibs) and whether SIRT3 could be a potential therapeutic target to improve mitochondrial function, SIRT3 concentrations in control fibroblasts, PH-Fibs, and lung tissues were determined using quantitative real-time PCR and western blot. SIRT3 deacetylase activity in cells and lung tissues was determined using western blot, immunohistochemistry staining, and immunoprecipitation. Glycolysis and mitochondrial function in fibroblasts were measured using respiratory analysis and fluorescence-lifetime imaging microscopy. The effects of restoring SIRT3 activity (by overexpression of SIRT3 with plasmid, activation SIRT3 with honokiol, and supplementation with the SIRT3 cofactor nicotinamide adenine dinucleotide [NAD+]) on mitochondrial protein acetylation, mitochondrial function, cell proliferation, and gene expression in PH-Fibs were also investigated. We found that SIRT3 concentrations were decreased in PH-Fibs and PH lung tissues, and its cofactor, NAD+, was also decreased in PH-Fibs. Increased acetylation in overall mitochondrial proteins and SIRT3-specific targets (MPC1 [mitochondrial pyruvate carrier 1] and MnSOD2 [mitochondrial superoxide dismutase]), as well as decreased MnSOD2 activity, was identified in PH-Fibs and PH lung tissues. Normalization of SIRT3 activity, by increasing its expression with plasmid or with honokiol and supplementation with its cofactor NAD+, reduced mitochondrial protein acetylation, improved mitochondrial function, inhibited proliferation, and induced apoptosis in PH-Fibs. Thus, our study demonstrated that restoration of SIRT3 activity in PH-Fibs can reduce mitochondrial protein acetylation and restore mitochondrial function and PH-Fib phenotype in PH.

Augmenting Mitochondrial Respiration in Immature Smooth Muscle Cells with an ACTA2 Pathogenic Variant Mitigates Moyamoya-like Cerebrovascular Disease

ACTA2 pathogenic variants altering arginine 179 cause childhood-onset strokes due to moyamoya disease (MMD)-like occlusion of the distal internal carotid arteries. A smooth muscle cell (SMC)-specific knock-in mouse model (Acta2SMC-R179C/+) inserted the mutation into 67% of aortic SMCs, whereas explanted SMCs were uniformly heterozygous. Acta2R179C/+ SMCs fail to fully differentiate and maintain stem cell-like features, including high glycolytic flux, and increasing oxidative respiration (OXPHOS) with nicotinamide riboside (NR) drives the mutant SMCs to differentiate and decreases migration. Acta2SMC-R179C/+ mice have intraluminal MMD-like occlusive lesions and strokes after carotid artery injury, whereas the similarly treated WT mice have no strokes and patent lumens. Treatment with NR prior to the carotid artery injury attenuates the strokes, MMD-like lumen occlusions, and aberrant vascular remodeling in the Acta2SMC-R179C/+ mice. These data highlight the role of immature SMCs in MMD-associated occlusive disease and demonstrate that altering SMC metabolism to drive quiescence of Acta2R179C/+ SMCs attenuates strokes and aberrant vascular remodeling in the Acta2SMC-R179C/+ mice.

Circulating choline levels are associated with prognoses in patients with pulmonary hypertension: a cohort study

BACKGROUNDS

Mounting evidences have highlighted the association between metabolites and cardiovascular diseases. Our previous works have demonstrated that circulating metabolite, trimethylamine oxide, was associated with prognosis of patients with pulmonary hypertension (PH). Choline is a precursor of trimethylamine oxide and its role in PH remains unknown. Here, we aimed to validate the hypothesis that circulating choline levels were associated with prognoses in patients with PH.

METHODS

Inpatients diagnosed with PH-defined as mean pulmonary arterial pressure ≥ 25 mmHg by right heart catheterisation-from Fuwai Hospital were enrolled after excluding relative comorbidities. Fasting blood samples were obtained to assess choline levels and other clinical variables. The primary endpoints were defined as death, escalation of targeted medication, rehospitalization due to heart failure, PH deterioration. The follow-up duration was defined as the time from the choline examination to the occurrence of outcomes or the end of the study. The associations between circulating choline levels and disease severity and prognoses were explored.

RESULTS

Totally, 272 inpatients with PH were enrolled in this study. Patients were divided into high and low choline groups according to the 50th quartile of circulating choline levels, defined as 12.6 µM. After confounders adjustment, the high circulating choline levels were still associated with poor World Health Organization functional class, elevated N-terminal pro-B-type natriuretic peptide, and decreased cardiac output index indicating the severe disease condition. Moreover, elevated choline levels were associated with poor prognoses in PH patients even after adjusting for confounders (hazard ratio = 1.934; 95% CI, 1.034-3.619; P = 0.039). Subgroup analyses showed that choline levels predicted the prognosis of patients with pulmonary arterial hypertension but not chronic thromboembolic pulmonary hypertension.

CONCLUSIONS

Choline levels were associated with disease severity and poor prognoses of patients with PH, especially in pulmonary arterial hypertension suggesting its potential biomarker role.