Guidelines for assessing maternal cardiovascular physiology during pregnancy and postpartum.

Maternal mortality rates are at an all-time high across the world and are set to increase in subsequent years. Cardiovascular disease is the leading cause of death during pregnancy and postpartum, especially in the United States. Therefore, understanding the physiological changes in the cardiovascular system during normal pregnancy is necessary to understand disease-related pathology. Significant systemic and cardiovascular physiological changes occur during pregnancy that are essential for supporting the maternal-fetal dyad. The physiological impact of pregnancy on the cardiovascular system has been examined in both experimental animal models and in humans. However, there is a continued need in this field of study to provide increased rigor and reproducibility. Therefore, these guidelines aim to provide information regarding best practices and recommendations to accurately and rigorously measure cardiovascular physiology during normal and cardiovascular disease-complicated pregnancies in human and animal models.

Tm4sf1-marked Endothelial Subpopulation Is Dysregulated in Pulmonary Arterial Hypertension.

The identification and role of endothelial progenitor cells in pulmonary arterial hypertension (PAH) remain controversial. Single-cell omics analysis can shed light on endothelial progenitor cells and their potential contribution to PAH pathobiology. We aim to identify endothelial cells that may have stem/progenitor potential in rat lungs and assess their relevance to PAH. Differential expression, gene set enrichment, cell-cell communication, and trajectory reconstruction analyses were performed on lung endothelial cells from single-cell RNA sequencing of Sugen-hypoxia, monocrotaline, and control rats. Relevance to human PAH was assessed in multiple independent blood and lung transcriptomic data sets. Rat lung endothelial cells were visualized by immunofluorescence in situ, analyzed by flow cytometry, and assessed for tubulogenesis in vitro. A subpopulation of endothelial cells (endothelial arterial type 2 [EA2]) marked by Tm4sf1 (transmembrane 4 L six family member 1), a gene strongly implicated in cancer, harbored a distinct transcriptomic signature enriched for angiogenesis and CXCL12 signaling. Trajectory analysis predicted that EA2 has a less differentiated state compared with other endothelial subpopulations. Analysis of independent data sets revealed that TM4SF1 is downregulated in lungs and endothelial cells from patients and PAH models, is a marker for hematopoietic stem cells, and is upregulated in PAH circulation. TM4SF1+CD31+ rat lung endothelial cells were visualized in distal pulmonary arteries, expressed hematopoietic marker CD45, and formed tubules in coculture with lung fibroblasts. Our study uncovered a novel Tm4sf1-marked subpopulation of rat lung endothelial cells that may have stem/progenitor potential and demonstrated its relevance to PAH. Future studies are warranted to further elucidate the role of EA2 and Tm4sf1 in PAH.

HNRNPA2B1: RNA-Binding Protein That Orchestrates Smooth Muscle Cell Phenotype in Pulmonary Arterial Hypertension.

BACKGROUND: RNA-binding proteins are master orchestrators of gene expression regulation. They regulate hundreds of transcripts at once by recognizing specific motifs. Thus, characterizing RNA-binding proteins targets is critical to harvest their full therapeutic potential. However, such investigation has often been restricted to a few RNA-binding protein targets, limiting our understanding of their function. In cancer, the RNA-binding protein HNRNPA2B1 (heterogeneous nuclear ribonucleoprotein A2B1; A2B1) promotes the pro-proliferative/anti-apoptotic phenotype. The same phenotype in pulmonary arterial smooth muscle cells (PASMCs) is responsible for the development of pulmonary arterial hypertension (PAH). However, A2B1 function has never been investigated in PAH. METHOD: Through the integration of computational and experimental biology, the authors investigated the role of A2B1 in human PAH-PASMC. Bioinformatics and RNA sequencing allowed them to investigate the transcriptome-wide function of A2B1, and RNA immunoprecipitation and A2B1 silencing experiments allowed them to decipher the intricate molecular mechanism at play. In addition, they performed a preclinical trial in the monocrotaline-induced pulmonary hypertension rat model to investigate the relevance of A2B1 inhibition in mitigating pulmonary hypertension severity. RESULTS: They found that A2B1 expression and its nuclear localization are increased in human PAH-PASMC. Using bioinformatics, they identified 3 known motifs of A2B1 and all mRNAs carrying them. In PAH-PASMC, they demonstrated the complementary nonredundant function of A2B1 motifs because all motifs are implicated in different aspects of the cell cycle. In addition, they showed that in PAH-PASMC, A2B1 promotes the expression of its targets. A2B1 silencing in PAH-PASMC led to a decrease of all tested mRNAs carrying an A2B1 motif and a concomitant decrease in proliferation and resistance to apoptosis. Last, in vivo A2B1 inhibition in the lungs rescued pulmonary hypertension in rats. CONCLUSIONS: Through the integration of computational and experimental biology, the study revealed the role of A2B1 as a master orchestrator of the PAH-PASMC phenotype and its relevance as a therapeutic target in PAH.

Y-Chromosome Gene, Uty, Protects Against Pulmonary Hypertension by Reducing Proinflammatory Chemokines.

Rationale: Idiopathic pulmonary arterial hypertension (PAH) is a terminal pulmonary vascular disease characterized by increased pressure, right ventricular failure, and death. PAH exhibits a striking sex bias and is up to four times more prevalent in females. Understanding the molecular basis behind sex differences could help uncover novel therapies. Objectives: We previously discovered that the Y chromosome is protective against hypoxia-induced experimental pulmonary hypertension (PH), which may contribute to sex differences in PAH. Here, we identify the gene responsible for Y-chromosome protection, investigate key downstream autosomal genes, and demonstrate a novel preclinical therapy. Methods: To test the effect of Y-chromosome genes on PH development, we knocked down each Y-chromosome gene expressed in the lung by means of intratracheal instillation of siRNA in gonadectomized male mice exposed to hypoxia and monitored changes in right ventricular and pulmonary artery hemodynamics. We compared the lung transcriptome of Uty knockdown mouse lungs to those of male and female PAH patient lungs to identify common downstream pathogenic chemokines and tested the effects of these chemokines on human pulmonary artery endothelial cells. We further inhibited the activity of these chemokines in two preclinical pulmonary hypertension models to test the therapeutic efficacy. Measurements and Main Results: Knockdown of the Y-chromosome gene Uty resulted in more severe PH measured by increased right ventricular pressure and decreased pulmonary artery acceleration time. RNA sequencing revealed an increase in proinflammatory chemokines Cxcl9 and Cxcl10 as a result of Uty knockdown. We found CXCL9 and CXCL10 significantly upregulated in human PAH lungs, with more robust upregulation in females with PAH. Treatment of human pulmonary artery endothelial cells with CXCL9 and CXCL10 triggered apoptosis. Inhibition of Cxcl9 and Cxcl10 expression in male Uty knockout mice and CXCL9 and CXCL10 activity in female rats significantly reduced PH severity. Conclusions:Uty is protective against PH. Reduction of Uty expression results in increased expression of proinflammatory chemokines Cxcl9 and Cxcl10, which trigger endothelial cell death and PH. Inhibition of CLXC9 and CXLC10 rescues PH development in multiple experimental models.

17 ß-Estradiol Impedes Aortic Root Dilation and Rupture in Male Marfan Mice.

Marfan syndrome causes a hereditary form of thoracic aortic aneurysms with worse outcomes in male compared to female patients. In this study, we examine the effects of 17 ß-estradiol on aortic dilation and rupture in a Marfan mouse model. Marfan male mice were administered 17 ß-estradiol, and the growth in the aortic root, along with the risk of aortic rupture, was measured. Transcriptomic profiling was used to identify enriched pathways from 17 ß-estradiol treatments. Aortic smooth muscle cells were then treated with cytokines to validate functional mechanisms. We show that 17 ß-estradiol decreased the size and rate of aortic root dilation and improved survival from rupture. The Marfan transcriptome was enriched in inflammatory genes, and the addition of 17 ß-estradiol modulated a set of genes that function through TNFα mediated NF-κB signaling. In addition, 17 ß-estradiol suppressed the induction of these TNFα induced genes in aortic smooth muscle cells in vitro in an NF-κB dependent manner, and 17 ß-estradiol decreased the formation of adventitial inflammatory foci in aortic roots in vivo. In conclusion, 17 ß-estradiol protects against the dilation and rupture of aortic roots in Marfan male mice through the inhibition of TNFα-NF-κB signaling.

Single-Cell Study of Two Rat Models of Pulmonary Arterial Hypertension Reveals Connections to Human Pathobiology and Drug Repositioning.

Rationale: The cellular and molecular landscape and translational value of commonly used models of pulmonary arterial hypertension (PAH) are poorly understood. Single-cell transcriptomics can enhance molecular understanding of preclinical models and facilitate their rational use and interpretation.Objectives: To determine and prioritize dysregulated genes, pathways, and cell types in lungs of PAH rat models to assess relevance to human PAH and identify drug repositioning candidates.Methods: Single-cell RNA sequencing was performed on the lungs of monocrotaline (MCT), Sugen-hypoxia (SuHx), and control rats to identify altered genes and cell types, followed by validation using flow-sorted cells, RNA in situ hybridization, and immunofluorescence. Relevance to human PAH was assessed by histology of lungs from patients and via integration with human PAH genetic loci and known disease genes. Candidate drugs were predicted using Connectivity Map.Measurements and Main Results: Distinct changes in genes and pathways in numerous cell types were identified in SuHx and MCT lungs. Widespread upregulation of NF-κB signaling and downregulation of IFN signaling was observed across cell types. SuHx nonclassical monocytes and MCT conventional dendritic cells showed particularly strong NF-κB pathway activation. Genes altered in SuHx nonclassical monocytes were significantly enriched for PAH-associated genes and genetic variants, and candidate drugs predicted to reverse the changes were identified. An open-access online platform was developed to share single-cell data and drug candidates (http://mergeomics.research.idre.ucla.edu/PVDSingleCell/).Conclusions: Our study revealed the distinct and shared dysregulation of genes and pathways in two commonly used PAH models for the first time at single-cell resolution and demonstrated their relevance to human PAH and utility for drug repositioning.

Role of miRNA-1 and miRNA-21 in Acute Myocardial Ischemia-Reperfusion Injury and Their Potential as Therapeutic Strategy.

Coronary artery disease remains the leading cause of death. Acute myocardial infarction (MI) is characterized by decreased blood flow to the coronary arteries, resulting in cardiomyocytes death. The most effective strategy for treating an MI is early and rapid myocardial reperfusion, but restoring blood flow to the ischemic myocardium can induce further damage, known as ischemia-reperfusion (IR) injury. Novel therapeutic strategies are critical to limit myocardial IR injury and improve patient outcomes following reperfusion intervention. miRNAs are small non-coding RNA molecules that have been implicated in attenuating IR injury pathology in pre-clinical rodent models. In this review, we discuss the role of miR-1 and miR-21 in regulating myocardial apoptosis in ischemia-reperfusion injury in the whole heart as well as in different cardiac cell types with special emphasis on cardiomyocytes, fibroblasts, and immune cells. We also examine therapeutic potential of miR-1 and miR-21 in preclinical studies. More research is necessary to understand the cell-specific molecular principles of miRNAs in cardioprotection and application to acute myocardial IR injury.

A novel miRNA biomarker panel associated with mortality in pediatric patients with ARDS.

We identified a novel microRNA biomarker panel consisting of 6 microRNAs predicting mortality in pediatric acute respiratory distress syndrome patients. Each of the identified mRNA have potential mechanistic importance in acute respiratory distress syndrome and may lead to the development of pharmacologic targets.

Sex differences underlying preexisting cardiovascular disease and cardiovascular injury in COVID-19.

The novel 2019 coronavirus disease (COVID-19), resulting from severe acute respiratory syndrome coronarvirus-2 (SARS-CoV-2) infection, typically leads to respiratory failure in severe cases; however, cardiovascular injury is reported to contribute to a substantial proportion of COVID-19 deaths. Preexisting cardiovascular disease (CVD) is among the most common risk factors for hospitalization and death in COVID-19 patients, and the pathogenic mechanisms of COVID-19 disease progression itself may promote the development of cardiovascular injury, increasing risk of in-hospital death. Sex differences in COVID-19 are becoming more apparent as mounting data indicate that males seem to be disproportionately at risk of severe COVID-19 outcome due to preexisting CVD and COVID-19-related cardiovascular injury. In this review, we will provide a basic science perspective on current clinical observations in this rapidly evolving field and discuss the interplay sex differences, preexisting CVD and COVID-19-related cardiac injury.

Pulmonary hypertension secondary to pulmonary fibrosis: clinical data, histopathology and molecular insights.

Pulmonary hypertension (PH) developing secondarily in pulmonary fibrosis (PF) patients (PF-PH) is a frequent co-morbidity. The high prevalence of PH in PF patients is very concerning since the presence of PH is a strong predictor of mortality in PF patients. Until recently, PH was thought to arise solely from fibrotic destruction of the lung parenchyma, leading to hypoxic vasoconstriction and loss of vascular bed density. Thus, potential cellular and molecular dysregulation of vascular remodeling as a driver of PF-PH has been under-investigated. The recent demonstrations that there is no correlation between the severity of the fibrosis and development of PH, along with the finding that significant vascular histological and molecular differences exist between patients with and without PH have shifted the etiological paradigm of PF-PH. This review aims to provide a comprehensive translational overview of PH in PF patients from clinical diagnosis and outcome to the latest understanding of the histology and molecular pathophysiology of PF-PH.

The Role of MicroRNAs in Acute Respiratory Distress Syndrome and Sepsis, From Targets to Therapies: A Narrative Review.

Acute respiratory distress syndrome (ARDS) is a significant cause of morbidity and mortality in the intensive care unit (ICU) and is characterized by lung epithelial and endothelial cell injury, with increased permeability of the alveolar-capillary membrane, leading to pulmonary edema, severe hypoxia, and difficulty with ventilation. The most common cause of ARDS is sepsis, and currently, treatment of ARDS and sepsis has consisted mostly of supportive care because targeted therapies have largely been unsuccessful. The molecular mechanisms behind ARDS remain elusive. Recently, a number of microRNAs (miRNAs) identified through high-throughput screening studies in ARDS patients and preclinical animal models have suggested a role for miRNA in the pathophysiology of ARDS. miRNAs are small noncoding RNAs ranging from 18 to 24 nucleotides that regulate gene expression via inhibition of the target mRNA translation or by targeting complementary mRNA for early degradation. Unsurprisingly, some miRNAs that are differentially expressed in ARDS overlap with those important in sepsis. In addition, circulatory miRNA may be useful as biomarkers or as targets for pharmacologic therapy. This can be revolutionary in a syndrome that has neither a measurable indicator of the disease nor a targeted therapy. While there are currently no miRNA-based therapies targeted for ARDS, therapies targeting miRNA have reached phase II clinical trials for the treatment of a wide range of diseases. Further studies may yield a unique miRNA profile pattern that serves as a biomarker or as targets for miRNA-based pharmacologic therapy. In this review, we discuss miRNAs that have been found to play a role in ARDS and sepsis, the potential mechanism of how particular miRNAs may contribute to the pathophysiology of ARDS, and strategies for pharmacologically targeting miRNA as therapy.

The Role of Estrogen Receptors in Cardiovascular Disease.

Cardiovascular Diseases (CVDs) are the leading cause of death globally. More than 17 million people die worldwide from CVD per year. There is considerable evidence suggesting that estrogen modulates cardiovascular physiology and function in both health and disease, and that it could potentially serve as a cardioprotective agent. The effects of estrogen on cardiovascular function are mediated by nuclear and membrane estrogen receptors (ERs), including estrogen receptor alpha (ERα), estrogen receptor beta (ERß), and G-protein-coupled ER (GPR30 or GPER). Receptor binding in turn confers pleiotropic effects through both genomic and non-genomic signaling to maintain cardiovascular homeostasis. Each ER has been implicated in multiple pre-clinical cardiovascular disease models. This review will discuss current reports on the underlying molecular mechanisms of the ERs in regulating vascular pathology, with a special emphasis on hypertension, pulmonary hypertension, and atherosclerosis, as well as in regulating cardiac pathology, with a particular emphasis on ischemia/reperfusion injury, heart failure with reduced ejection fraction, and heart failure with preserved ejection fraction.

Paraoxonase 2 protects against acute myocardial ischemia-reperfusion injury by modulating mitochondrial function and oxidative stress via the PI3K/Akt/GSK-3ß RISK pathway.

OBJECTIVE: To investigate the novel role of Paraoxonase 2 (PON2) in modulating acute myocardial ischemia-reperfusion injury (IRI). APPROACH: IRI was induced both in vivo and ex vivo in male, C57BL6/J (WT) and PON2-deficient (PON-def) mice. In addition, in vitro hypoxia-reoxygenation injury (HRI) was induced in H9c2 cells expressing empty vector (H9c2-EV) or human PON2 (H9c2-hPON2) ±â€¯LY294002 (a potent PI3K inhibitor). Infarct size, PON2 gene expression, mitochondrial calcium retention capacity (CRC), reactive oxygen species (ROS) generation, mitochondrial membrane potential, CHOP and pGSK-3ß protein levels, and cell apoptosis were evaluated. RESULTS: PON2 gene expression is upregulated in WT mice following in vivo IRI. PON2-def mice exhibit a 2-fold larger infarct, increased CHOP levels, and reduced pGSK-3ß levels compared to WT controls. Global cardiac mitochondria isolated from PON2-def mice exhibit reduced CRC and increased ROS production. Cardiomyocytes isolated from PON2-def mice subjected to ex vivo IRI have mitochondria with reduced CRC (also seen under non-IRI conditions), and increased ROS generation and apoptosis compared to WT controls. PON2 knockdown in H9c2 cells subjected to HRI leads to an increase in mitochondrial membrane depolarization. H9c2-hPON2 cells exhibit i) improvement in mitochondrial membrane potential, pGSK-3ß levels and mitochondrial CRC, and ii) decrease in CHOP levels, mitochondrial ROS generation and cell apoptosis, when compared to H9c2-EV controls. Treatment with LY294002 resulted in a decrease of mitochondrial CRC and increase in mitochondrial ROS production and cell apoptosis in the H9c2-hPON2 group versus H9c2-EV controls. CONCLUSION: PON2 protects against acute myocardial IRI by reducing mitochondrial dysfunction and oxidative stress in cardiomyocytes via activation of the PI3K/Akt/GSK-3ß RISK pathway.

Progression of myocardial ischemia leads to unique changes in immediate-early gene expression in the spinal cord dorsal horn.

The pathological consequences of ischemic heart disease involve signaling through the autonomic nervous system. Although early activation may serve to maintain hemodynamic stability, persistent aberrant sympathoexcitation contributes to the development of lethal arrhythmias and heart failure. We hypothesized that as the myocardium reacts and remodels to ischemic injury over time, there is an analogous sequence of gene expression changes in the thoracic spinal cord dorsal horn, the processing center for incoming afferent fibers from the heart to the central nervous system. Acute and chronic myocardial ischemia (MI) was induced in a large animal model of Yorkshire pigs, and the thoracic dorsal horn of treated pigs, along with control nonischemic pigs, was harvested for transcriptome analysis. We identified 32 differentially expressed genes between healthy and acute ischemia cohorts and 46 differentially expressed genes between healthy and chronic ischemia cohorts. The canonical immediate-early gene c-fos was upregulated after acute MI, along with fosB, dual specificity phosphatase 1 and 2 ( dusp1 and dusp2), and early growth response 2 (egr2). After chronic MI, there was a persistent yet unique activation of immediate-early genes, including fosB, nuclear receptor subfamily 4 group A members 1-3 ( nr4a1, nr4a2, and nr4a3), egr3, and TNF-α-induced protein 3 ( tnfaip3). In addition, differentially expressed genes from the chronic MI signature were enriched in pathways linked to apoptosis, immune regulation, and the stress response. These findings support a dynamic progression of gene expression changes in the dorsal horn with maturation of myocardial injury, and they may explain how early adaptive autonomic nervous system responses can maintain hemodynamic stability, whereas prolonged maladaptive signals can predispose patients to arrhythmias and heart failure. NEW & NOTEWORTHY Activation of the autonomic nervous system after myocardial injury can provide early cardiovascular support or prolonged aberrant sympathoexcitation. The later response can lead to lethal arrhythmias and heart failure. This study provides evidence of ongoing changes in the gene expression signature of the spinal cord dorsal horn as myocardial injury progresses over time. These changes could help explain how an adaptive nervous system response can become maladaptive over time.

Free Fatty Acid Receptor G-protein-coupled Receptor 40 Mediates Lipid Emulsion-induced Cardioprotection.

BACKGROUND: We have previously shown that intralipid (lipid emulsion) protects the heart against ischemia/reperfusion injury and bupivacaine-induced cardiotoxicity. However, the precise underlying mechanisms are not fully understood. Here we explored the hypothesis that free fatty acid receptor-1 or G-protein-coupled receptor 40 is expressed in the heart and that cardioprotective effects of lipid emulsion are mediated through G-protein-coupled receptor 40 in two animal models of ischemia/reperfusion injury and bupivacaine-induced cardiotoxicity. METHODS: Langendorff-perfused male mouse hearts were subjected to ischemia/reperfusion with lipid emulsion alone (1%) or with G-protein-coupled receptor 40 antagonist (GW1100, 10 µM). Additionally, cardiotoxicity was achieved in male rats with bupivacaine bolus (10 mg/kg, IV) followed by lipid emulsion alone (20%, 5 ml/kg bolus, and 0.5 ml · kg · min maintenance, IV) or with GW1100 pretreatment (2.5 mg/kg, IV). RESULTS: G-protein-coupled receptor 40 is expressed in rodent hearts. GW1100 abolished lipid emulsion-induced cardioprotection against ischemia/reperfusion in mice because rate pressure product and left ventricular developed pressure were lower than lipid emulsion alone (rate pressure product: 2,186 ± 1,783 [n = 7] vs. 11,607 ± 4,347 [n = 8]; left ventricular developed pressure: 22.6 ± 10.4 vs. 63.8 ± 20; P < 0.0001). Lipid emulsion + GW1100 also demonstrated reduced LV dP/dtmax and LV dP/dtmin (dP/dtmax = 749 ± 386 vs. 2,098 ± 792, P < 0.001; dP/dtmin = -443 ± 262 vs. -1,447 ± 546, P < 0.001). In bupivacaine-induced cardiotoxicity rat model, GW1100 pretreatment had no significant effect on heart rate (HR) and ejection fraction after 30 min (HR: 302 ± 17 vs. 312 ± 38; ejection fraction: 69 ± 3% vs. 73 ± 4%). GW1100 pretreatment, however, prevented lipid-rescue, with no recovery after 10 min. In the control group, lipid emulsion improved HR (215 ± 16 at 10 min) and fully rescued left ventricle function at 10 min (ejection fraction = 67 ± 8%, fractional shortening = 38 ± 6%). CONCLUSIONS: G-protein-coupled receptor 40 is expressed in the rodent heart and is involved in cardioprotection mediated by lipid emulsion against ischemia/reperfusion injury and bupivacaine-induced cardiotoxicity.

Sex Hormones and Sex Chromosomes Cause Sex Differences in the Development of Cardiovascular Diseases.

This review summarizes recent evidence concerning hormonal and sex chromosome effects in obesity, atherosclerosis, aneurysms, ischemia/reperfusion injury, and hypertension. Cardiovascular diseases occur and progress differently in the 2 sexes, because biological factors differing between the sexes have sex-specific protective and harmful effects. By comparing the 2 sexes directly, and breaking down sex into its component parts, one can discover sex-biasing protective mechanisms that might be targeted in the clinic. Gonadal hormones, especially estrogens and androgens, have long been found to account for some sex differences in cardiovascular diseases, and molecular mechanisms mediating these effects have recently been elucidated. More recently, the inherent sexual inequalities in effects of sex chromosome genes have also been implicated as contributors in animal models of cardiovascular diseases, especially a deleterious effect of the second X chromosome found in females but not in males. Hormonal and sex chromosome mechanisms interact in the sex-specific control of certain diseases, sometimes by opposing the action of the other.

An Introduction to Epigenetics in Cardiovascular Development, Disease, and Sexualization.

Epigenetic regulation of gene expression is integral to cell differentiation, development, and disease. Modes of epigenetic regulation-including DNA methylation, histone modifications, and ncRNA-based regulation-alter chromatin structure, promotor accessibility, and contribute to posttranscriptional modifications. In the cardiovascular system, epigenetic regulation is necessary for proper cardiovascular development and homeostasis, while epigenetic dysfunction is associated with improper cardiac development and disease.Early sexualization of tissues, including X-inactivation in females and maternal and paternal imprinting, is also orchestrated through epigenetic mechanisms. Furthermore, sex chromosomes encode various sex-specific genes involved in epigenetic regulation, while sex hormones can act as regulatory cofactors that may predispose or protect males and females against developing diseases with a marked sex bias.The following book chapter summarizes the field of epigenetics in the context of cardiovascular development and disease while also highlighting the role of epigenetic regulation as a powerful source of sex differences within the cardiovascular system.

Intralipid protects the heart in late pregnancy against ischemia/reperfusion injury via Caveolin2/STAT3/GSK-3ß pathway.

BACKGROUND: We recently demonstrated that the heart of late pregnant (LP) rodents is more prone to ischemia/reperfusion (I/R) injury compared to non-pregnant rodents. Lipids, particularly polyunsaturated fatty acids, have received special attention in the field of cardiovascular research. Here, we explored whether Intralipid (ITLD) protects the heart against I/R injury in LP rodents and investigated the mechanisms underlying this protection. METHODS AND RESULTS: In-vivo female LP rat hearts or ex-vivo isolated Langendorff-perfused LP mouse hearts were subjected to ischemia followed by reperfusion with PBS or ITLD (one bolus of 5mg/kg of 20% in in-vivo and 1% in ex-vivo). Myocardial infarct size, mitochondrial calcium retention capacity, genome-wide expression profiling, pharmacological inhibition and co-immunoprecipitation were performed. One bolus of ITLD at reperfusion significantly reduced the in-vivo myocardial infarct size in LP rats (23.3±2% vs. 55.5±3.4% in CTRL, p<0.01). Postischemic administration of ITLD also protected the LP hearts against I/R injury ex-vivo. ITLD significantly increased the threshold for the opening of the mitochondrial permeability transition pore in response to calcium overload (nmol-calcium/mg-mitochondrial protein: 290±17 vs. 167±10 in CTRL, p<0.01) and significantly increased phosphorylation of STAT3 (1.8±0.08 vs. 1±0.16 in CTRL, p<0.05) and GSK-3ß (2.63±0.55 vs. 1±0.0.34 in CTRL, p<0.05). The ITLD-induced cardioprotection was fully abolished by Stattic, a specific inhibitor of STAT3. Transcriptome analysis revealed caveolin 2 (Cav2) was significantly upregulated by ITLD in hearts of LP rats under I/R injury. Co-immunoprecipitation experiments showed that Cav2 interacts with STAT3. CONCLUSIONS: ITLD protects the heart in late pregnancy against I/R injury by inhibiting the mPTP opening through Cav2/STAT3/GSK-3ß pathway.

Autonomic nervous system involvement in pulmonary arterial hypertension.

Pulmonary arterial hypertension (PAH) is a chronic pulmonary vascular disease characterized by increased pulmonary vascular resistance (PVR) leading to right ventricular (RV) failure. Autonomic nervous system involvement in the pathogenesis of PAH has been demonstrated several years ago, however the extent of this involvement is not fully understood. PAH is associated with increased sympathetic nervous system (SNS) activation, decreased heart rate variability, and presence of cardiac arrhythmias. There is also evidence for increased renin-angiotensin-aldosterone system (RAAS) activation in PAH patients associated with clinical worsening. Reduction of neurohormonal activation could be an effective therapeutic strategy for PAH. Although therapies targeting adrenergic receptors or RAAS signaling pathways have been shown to reverse cardiac remodeling and improve outcomes in experimental pulmonary hypertension (PH)-models, the effectiveness and safety of such treatments in clinical settings have been uncertain. Recently, novel direct methods such as cervical ganglion block, pulmonary artery denervation (PADN), and renal denervation have been employed to attenuate SNS activation in PAH. In this review, we intend to summarize the multiple aspects of autonomic nervous system involvement in PAH and overview the different pharmacological and invasive strategies used to target autonomic nervous system for the treatment of PAH.