Hematological disorders and pulmonary hypertension

Hypoxia-induced pulmonary hypertension in adults and newborns: implications for drug development

Chronic hypoxia-induced pulmonary hypertension (CHPH) presents a complex challenge, characterized by escalating pulmonary vascular resistance and remodeling, threatening both newborns and adults with right heart failure. Despite advances in understanding the pathobiology of CHPH, its molecular intricacies remain elusive, particularly because of the multifaceted nature of arterial remodeling involving the adventitia, media, and intima. Cellular imbalance arises from hypoxia-induced mitochondrial disturbances and oxidative stress, reflecting the diversity in pulmonary hypertension (PH) pathology. In this review, we highlight prominent mechanisms causing CHPH in adults and newborns, and emerging therapeutic targets of potential pharmaceuticals.

Association and risk factors of pediatric pulmonary hypertension with obstructive sleep apnea: A national study utilizing the Kids' Inpatient Database (KID)

STUDY OBJECTIVE

Assess the prevalence of and risk factors for pediatric pulmonary hypertension (PH) in the 2016 Kids' Inpatient Database (KID), including obstructive sleep apnea (OSA) and obesity.

METHODS

Retrospective cross-sectional cohort study utilizing 6,081,132 weighted pediatric discharges from the 2016 KID. Study variables included age, length of stay, mortality, gender, hospital region, primary payer, race, median household income for patient's ZIP code, OSA, central sleep apnea (CSA), obesity, Down syndrome, sickle cell disease (SCD), thalassemia, congenital heart disease (CHD), hypertension, asthma and chronic lung disease of prematurity (CLDP). PH was the primary outcome of interest. Bivariate and multivariable logistic regression models were utilized with odds ratios and 95 % confidence intervals.

RESULTS

The mean age was 3.76 years, the mean hospital length of stay was 3.85 days, 48.9 % were male, 52.6 % had government health insurance, 51.0 % were White, 16.1 % were Black, 21.1 % were Hispanic, 5.0 % were Asian or Pacific Islander, 0.80 % were Native American and 6.1 % identified as "other". The prevalence of PH was 0.21 % (12,777 patients). There were 37,631 patients with OSA and the prevalence of PH among this cohort was 3.3 %, over 10x greater than the overall prevalence of PH in the 2016 KID (0.21 %). Risk factors associated with PH included CLDP, CHD, Down syndrome, asthma, OSA, CSA, hypertension, SCD, obesity, race/ethnicity, government insurance, age, male gender (p < 0.0001), and hospital region (p = 0.0002).

CONCLUSIONS

Several risk factors were independently associated with PH, such as OSA, CSA, obesity, asthma, and insurance status. Prospective multi-institutional studies are needed to assess the relationships between these risk factors, severity metrics, and causative links in the development of PH; in addition to identifying children with OSA who are most likely to benefit from cardiopulmonary screening prior to adenotonsillectomy.

LEVEL OF EVIDENCE

Level III.

Chronic anemia complicated by cardiac failure, pulmonary hypertension, and pericardial effusion: a case report

BACKGROUND

Worldwide, iron deficiency anaemia (IDA) is the most common cause of anaemia. Iron deficiency alone has an association with heart failure and pulmonary hypertension. Chronic iron deficiency anemia triggers various physiologic adjustments, leading to hyperdynamic circulation and enhanced hypoxic pulmonary vasoconstriction. Those mechanisms may result in the development of high output cardiac failure and pulmonary hypertension; however, pericardial effusion remains a rare association.

CASE PRESENTATION

A 44-year-old Nepalese man presented with fatigability and swollen ankles. Except for a hemorrhoidectomy 4 years ago, he had no comorbidities. Labs confirmed severe iron deficiency anemia (hemoglobin 1.8 grams per deciliter) likely secondary to hemorrhoids. An echocardiogram revealed high output cardiac failure, pericardial effusion, and severe pulmonary hypertension. He responded well to the correction of anemia and diuretics with the resolution of vascular complications.

CONCLUSION

We report a unique presentation of chronic severe iron deficiency anemia complicated by heart failure, pulmonary hypertension, and pericardial effusion. We believe it to be the first-ever such case reported in the literature. These cardiovascular complications seem to result from internal homeostatic mechanisms against the chronic tissue hypoxemia observed in severe anemia. Furthermore, iron deficiency alone has an association with heart failure and pulmonary hypertension. After excluding other potential causes, we confirmed iron deficiency anaemia as the cause of those complications. The correction of anemia led to an excellent recovery without any sequelae. Our case report highlights the fact that management of such a case should be focused on underlying etiology rather than the complications.

Prognostic value of multiparametric cardiac magnetic resonance in sickle cell patients

The aim of this multicenter study was to prospectively assess the predictive value of multiparametric cardiac magnetic resonance (CMR) for cardiovascular complications in sickle cell disease (SCD) patients. Among all patients with hemoglobinopathies consecutively enrolled in the Myocardial Iron Overload in Thalassemia (MIOT) Network, we selected 102 SCD patients (34.38 ± 12.67 years, 49 females). Myocardial iron overload (MIO) was measured by the multislice multiecho T2* technique. Atrial dimensions and biventricular function parameters were quantified by cine images. Late gadolinium enhancement (LGE) images were acquired to detect focal myocardial fibrosis. At baseline CMR, only two patients had significant MIO (global heart T2* < 20 ms). During a mean follow-up of 63.01 ± 24.95 months, 11 cardiovascular events (10.8%) were registered: 3 pulmonary hypertension, 2 supraventricular arrhythmias, 1 heart failure, 1 death for heart failure, 1 pulmonary embolism, 1 peripheral vascular disease, 1 transient ischemic attack, and 1 death after acute chest syndrome. In the multivariate analysis, the independent CMR predictors of cardiovascular events were left ventricular (LV) ejection fraction (hazard ratio-HR = 0.88; p = 0.025) and right ventricular (RV) mass index (HR = 1.09; p = 0.047). According to the receiver-operating characteristic curve analysis for adverse events, an LV ejection fraction < 58.9% and an RV mass index > 31 g/m² were optimal cut-off values. Reduced left ventricular ejection fraction and increased right ventricular mass index showed a significant prognostic value in patients with SCD. Our data seem to suggest that CMR may be added as a screening tool for identifying SCD patients at high risk for cardiopulmonary and vascular diseases.

The obstetric implications of pulmonary hypertension and lung transplant

Pulmonary hypertension (PH) is present when the mean pulmonary artery pressure is elevated to >20 mmHg as determined by right heart catheterization. It is categorized into five groups according to the underlying causes. Its presence is considered a contraindication to pregnancy for which therapeutic termination is usually advised due to grave maternal prognosis and pregnancy outcome. Nevertheless, pregnancies in affected women are increasingly reported, about half of which were unplanned, and two-thirds resulted in live births without increased foetal anomalies, notwithstanding increased risks of preterm birth, low birth weight, pre-eclampsia, other obstetric complications, and medical comorbidities, when managed under a multidisciplinary team in specialized centres. Successful lung transplant, the ultimate treatment for PH and other progressive lung diseases, restores fertility, and pregnancy is increasingly encountered, but there is a higher risk of graft rejection and mortality, compared with recipients of other organs. Preconception assessment is vital in optimizing maternal and pregnancy outcomes.

Vanillic Acid Attenuates Monocrotaline-Induced Pulmonary Arterial Hypertension by Enhancing NO Signaling Pathways

Pulmonary arterial hypertension (PAH) is a severe progressive disease characterized by elevated mean pulmonary arterial pressure, right ventricular hypertrophy, and eventual progression to right heart failure and death. This study aimed to examine the effect of the natural product vanillic acid (VA) on monocrotaline (MCT)-induced PAH in rats. The arginase inhibitory activity and enzyme kinetic reaction of VA were also investigated. The results showed that VA could improve pulmonary arterial pressure, pulmonary artery vascular remodeling, and right ventricular remodeling induced by MCT in rats and reduce the degree of pulmonary tissue fibrosis. Moreover, VA downregulated the gene and protein expression levels of Hif-2α, Hif-1β, and Arg2 and increased the P-eNOS/eNOS levels, thus increasing nitric oxide (NO) levels in PAH rats. Furthermore, VA was determined to be a mixed competitive arginase inhibitor with an IC50 of 26.1 μM. In conclusion, the arginase inhibitor VA exerted protective effects on MCT-induced PAH and pulmonary vascular remodeling by enhancing NO signaling pathways.

[Pulmonary Hypertension and Polycythemia vera]

INTRODUCTION

 Chronic myeloproliferative diseases are rare causes of PH class 5 according to Nice classification 2018. The present case reports show different courses, on the one hand with a primary manifestation of a PH and subsequently a PV, on the other hand with the development of a PH in the context of a PV.

CASE REPORTS

 1) At first contact, a 75-year-old female patient who complained progressive dyspnea and had evidence of stress-PH in the right heart catheter. During the course she developed a resting PH of up to 70 mmHg systolic despite initial monotherapy and subsequent dual therapy for PH. After 5 years she had the diagnosis of polycythemia vera, treated with hydroxycarbamide and subsequent phlebotomies. In the further course increasing cardiac decompensation and death. 2) 74-year-old female patient at the time of diagnosis of chronic megakaryocytic-granulocytic myelosis. After 7 years, evidence of polycythemia vera (V617F mutation in the JAK2 gene), a monoclonal gammopathy. In the case of splenomegaly, irradiation of the spleen was carried out and, after 1 year, therapy with ruxolitinib was started. After another 2 years, with increasing dyspnea, pulmonary hypertension (CTEPH) with a PA-mean of 43 mmHg and a PVR of 4.5 WE were detected. With anticoagulation and riociguat therapy exercise capacity and PA pressures were only temporarily improved. Within 1 year restrictive ventilation, hypoxemia, heart failure (EF 45 %) with leading right heart decompensation and cardiorenal syndrome developed. Dialysis showed only short-term recompensation, and the patient died.

DISCUSSION

 The case reports are characterized by a combination of PV and PH, with different temporal sequence, as well as only a low influence of PH-specific therapy, with subsequent progressive cardiac decompensation. Thus, they reflect the different etiologies, clinical manifestations, and the low therapeutic influence of PH in myeloproliferative disorders. The value of PH-specific therapy remains unclear, especially in view of different pathomechanisms in the genesis of PH.

CONCLUSION

 Patients with myeloproliferative diseases require screening for PH. In the course of PH, myeloproliferative disease can unmask or develop. The therapeutic influence on PH is limited.

An Update on Arginase Inhibitors and Inhibitory Assays

Arginase, which converts arginine into ornithine and urea, is a promising therapeutic target. Arginase is involved in cardiovascular diseases, parasitic infections and, through a critical role in immunity, in some cancers. There is a need to develop effective arginase inhibitors and therefore efforts to identify and optimize new inhibitors are increasing. Several methods of evaluating arginase activity are available, but few directly measure the product. Radiometric assays need to separate urea and dying reactions require acidic conditions and sometimes heating. Hence, there are a variety of different approaches available, and each approach has its own limits and benefits. In this review, we provide an update on arginase inhibitors, followed by a discussion on available arginase assays and alternative methods, with a focus on the intrinsic biases and parameters that are likely to impact results.

miRNA profile and disease severity in patients with sickle cell anemia

Identification of biomarkers associated with severity in sickle cell anemia is desirable. Circulating serum microRNAs (miRNA) are targets studied as diagnostic or prognostic markers, but few studies have been conducted in sickle cell anemia. The purpose of this study is to identify specific signatures of miRNAs in plasma samples from sickle cell anemia patients according to severity indexes. Screening of the miRNAs expression was performed in 8 patients, classified by tricuspid regurgitation velocity (TRV) measure: 4 with TRV ≥ 2.5 m/s and 4 with TRV < 2.5 m/s. The samples were analyzed by real-time PCR using Megaplex RT Human Pool A and Pool B comprising 667 distinct miRNAs. Seventeen miRNAs were differentially expressed between the two groups (p < 0.05). Five differentially expressed miRNAs (miR15b, miR502, miR510, miR544, miR629) were selected for validation in a cohort of 52 patient samples, 26 with TRV ≥ 2.5 m/s. Another two severity scores were also used: organ injury score (OIS) and Bayesian score (BS). Univariate binary logistic regressions were performed to analyze the data. Five out of 17 differentially expressed miRNAs were selected for validation in 52 patient samples: miR15b, miR502, miR510, miR544, and miR629. Two miRNAs (miR510 and miR629) were significantly decreased in cases of greater severity. Whereas miR510 expression discriminated the patients according to TRV and OIS, miR629 expression did it according to BS. This is the first study investigating plasma miRNAs as possible biomarkers for SCA severity. Our data suggest that low levels of miR510 and miR629 expression are associated with greater SCA disease severity. Further studies are still necessary to elucidate mechanism of these miRNAs and their related proteins.

Protein network analyses of pulmonary endothelial cells in chronic thromboembolic pulmonary hypertension

Chronic thromboembolic pulmonary hypertension (CTEPH) is a vascular disease characterized by the presence of organized thromboembolic material in pulmonary arteries leading to increased vascular resistance, heart failure and death. Dysfunction of endothelial cells is involved in CTEPH. The present study describes for the first time the molecular processes underlying endothelial dysfunction in the development of the CTEPH. The advanced analytical approach and the protein network analyses of patient derived CTEPH endothelial cells allowed the quantitation of 3258 proteins. The 673 differentially regulated proteins were associated with functional and disease protein network modules. The protein network analyses resulted in the characterization of dysregulated pathways associated with endothelial dysfunction, such as mitochondrial dysfunction, oxidative phosphorylation, sirtuin signaling, inflammatory response, oxidative stress and fatty acid metabolism related pathways. In addition, the quantification of advanced oxidation protein products, total protein carbonyl content, and intracellular reactive oxygen species resulted increased attesting the dysregulation of oxidative stress response. In conclusion this is the first quantitative study to highlight the involvement of endothelial dysfunction in CTEPH using patient samples and by network medicine approach.

Evaluation of hemodynamic parameters among patients with myeloproliferative neoplasms and suspected pulmonary hypertension

Myeloproliferative neoplasms (MPNs) are associated with pulmonary hypertension (PH). We studied MPN patients who underwent right-heart-catheterization (RHC) to identify hemodynamic differences between MPN-subtypes. Per RHC, hemodynamics were classified as pre, post or combined pre and post-capillary PH. One-way analysis-of-variance (ANOVA) was used to compare hemodynamic differences among MPN-subtypes. Correlation of RVSP between trans-thoracic echocardiography (TTE) and RHC was evaluated. We included 68 patients. Median age was 63. Fifty-nine percent were male and 87% Caucasian. Polycythemia vera and essential thrombocythemia were the most common subtypes. On TTE, 91.5% had PH. On RHC, only 29% met criteria for pre-capillary PH. No MPN-subtype was more likely than others to have pre-capillary PH. Bland-Altman analysis showed significant intra-person variability between TTE and RHC-derived right ventricular systolic pressures. Post-capillary involvement is more common than precapillary PH in MPN. Type of PH does not appear to differ by MPN-subtype.

Gamma heavy chain disease complicated by pulmonary hypertension, which was successfully treated with lenalidomide

Heavy chain disease (HCD) is a rare B-cell proliferative neoplasm that is characterised by the production of truncated monoclonal immunoglobulin heavy chains without light chains. Gamma HCD is a subgroup of HCD. A 67-year-old man was admitted to our hospital with dyspnoea and lower leg oedema. Based on the results of heart catheterisation, he was diagnosed with pulmonary hypertension. Laboratory tests revealed an elevated level of IgG, and serum immunoelectrophoresis showed that IgG was a monoclonal gamma heavy chain without light chains. Finally, he was diagnosed with gamma HCD complicated by pulmonary hypertension. Bortezomib and dexamethasone therapy was initiated, but became refractory within 8 months. Therefore, the treatment was switched to lenalidomide and dexamethasone therapy, and the disease has been stably controlled for more than 2 years. To the best of our knowledge, this is the first case of gamma HCD being successfully treated by lenalidomide and dexamethasone therapy.

Vascular endothelial growth factor and pulmonary hypertension in children with beta thalassemia major

OBJECTIVE

The purpose of this study was to illustrate the association between vascular endothelial growth factor level and pulmonary artery hypertension in children with β-thalassemia major.

METHOD

This case-control study was conducted on 116 children with β-thalassemia major; 58 of them had pulmonary artery hypertension. They were compared to 58 healthy children who were age and sex-matched (control group). Serum levels of vascular endothelial growth factor and echocardiographic assessment were done for all children.

RESULTS

Vascular endothelial growth factor serum level was significantly higher in children with β-thalassemia major with pulmonary artery hypertension than in those without pulmonary artery hypertension, as well as in control groups (p<0.001). Vascular endothelial growth factor serum level had a significant positive correlation with pulmonary artery pressure and serum ferritin, as well as a significant negative correlation with the duration of chelation therapy. Logistic regression analysis revealed that elevated vascular endothelial growth factor (Odd Ratio=1.5; 95% Confidence Interval, 1.137-2.065; p=0.005) was an independent risk factor of pulmonary artery hypertension in such children. Vascular endothelial growth factor serum level at a cutoff point of >169pg/mL had 93.1% sensitivity and 93.1% specificity for the presence of pulmonary artery hypertension in children with β-thalassemia major.

CONCLUSION

Elevated vascular endothelial growth factor serum level is associated with pulmonary artery hypertension in children with β-thalassemia.

Newborn Infant With Mothball Toxicity Due to Maternal Ingestion

Naphthalene poisoning due to exposure to mothballs is a common cause of toxicity in children worldwide. Naphthalene toxicity is known to cause hemolytic anemia, methemoglobinemia, and hepatic and renal injury. Neonates are more susceptible to the effects of oxidative stress from naphthalene because of their low glutathione stores and immaturity of hepatic enzymes. However, there are no reported cases of chronic fetal exposure to naphthalene during pregnancy. We report a novel case of chronic fetal exposure to naphthalene-containing mothballs that occurred from the second trimester through the third trimester of pregnancy. Our patient presented with hyperbilirubinemia, requiring exchange transfusion, severe hemolytic anemia, pulmonary hypertension, respiratory failure, and renal failure and progressed to develop "bronze baby" syndrome. Pregnant mothers should be diligently screened for such exposures and if found should receive psychiatric evaluation and counseling to prevent such devastating effects in neonates.

Role of Gender in Regulation of Redox Homeostasis in Pulmonary Arterial Hypertension

Pulmonary arterial hypertension (PAH) is one of the diseases with a well-established gender dimorphism. The prevalence of PAH is increased in females with a ratio of 4:1, while poor survival prognosis is associated with the male gender. Nevertheless, the specific contribution of gender in disease development and progression is unclear due to the complex nature of the PAH. Oxidative and nitrosative stresses are important contributors in PAH pathogenesis; however, the role of gender in redox homeostasis has been understudied. This review is aimed to overview the possible sex-specific mechanisms responsible for the regulation of the balance between oxidants and antioxidants in relation to PAH pathobiology.

Hemolysis-induced Lung Vascular Leakage Contributes to the Development of Pulmonary Hypertension

Although hemolytic anemia-associated pulmonary hypertension (PH) and pulmonary arterial hypertension (PAH) are more common than the prevalence of idiopathic PAH alone, the role of hemolysis in the development of PAH is poorly characterized. We hypothesized that hemolysis independently contributes to PAH pathogenesis via endothelial barrier dysfunction with resulting perivascular edema and inflammation. Plasma samples from patients with and without PAH (both confirmed by right heart catheterization) were used to measure free hemoglobin (Hb) and its correlation with PAH severity. A sugen (50 mg/kg)/hypoxia (3 wk)/normoxia (2 wk) rat model was used to elucidate the role of free Hb/heme pathways in PAH. Human lung microvascular endothelial cells were used to study heme-mediated endothelial barrier effects. Our data indicate that patients with PAH have increased levels of free Hb in plasma that correlate with PAH severity. There is also a significant accumulation of free Hb and depletion of haptoglobin in the rat model. In rats, perivascular edema was observed at early time points concomitant with increased infiltration of inflammatory cells. Heme-induced endothelial permeability in human lung microvascular endothelial cells involved activation of the p38/HSP27 pathway. Indeed, the rat model also exhibited increased activation of p38/HSP27 during the initial phase of PH. Surprisingly, despite the increased levels of hemolysis and heme-mediated signaling, there was no heme oxygenase-1 activation. This can be explained by observed destabilization of HIF-1a during the first 2 weeks of PH regardless of hypoxic conditions. Our data suggest that hemolysis may play a significant role in PAH pathobiology.

Critical Care of Patients After Pulmonary Thromboendarterectomy

Pulmonary thromboendarterectomy (PTE) remains the only curative surgery for patients with chronic thromboembolic pulmonary hypertension (CTEPH). Postoperative intensive care unit care challenges providers with unique disease physiology, operative sequelae, and the potential for detrimental complications. Central concerns in patients with CTEPH immediately after PTE relate to neurologic, pulmonary, hemodynamic, and hematologic aspects. Institutional experience in critical care for the CTEPH population, a multidisciplinary team approach, patient risk assessment, and integration of current concepts in critical care determine outcomes after PTE surgery. In this review, the authors will focus on specific aspects unique to this population, with integration of current available evidence and future directions. The goal of this review is to provide the cardiac anesthesiologist and intensivist with a comprehensive understanding of postoperative physiology, potential complications, and contemporary intensive care unit management immediately after pulmonary endarterectomy.

Pulmonary hypertension with massive megalosplenia: A case report

RATIONALE

Pulmonary hypertension (PH) is a complicated disease which has complex causes and poor outcome. Many factors are involved in the increase of pulmonary artery pressure. It is often difficult to identify the specific cause of a particular patient. However, identifying the etiology is of great importance for specifying treatment strategies and improving the prognosis of patients.

PATIENT CONCERNS

A 58-year-old male was admitted because of fatigue, breath shortness for 6 months, which got worse in the last 3 months. The ultrasound cardiogram (UCG) indicated a remarkably elevated pulmonary artery systolic pressure (PASP = 82 mm Hg). He had hypertension for 15 years. Besides, his spleen was found to be enlarged since 15 years ago. Bone marrow biopsy of the patient revealed myeloproliferative neoplasm (MPN) with severe myelofibrosis (MF).

DIAGNOSIS

Myeloproliferative neoplasm (MPN) with severe myelofibrosis (MF) which in turn caused PH and portal vein hypertension (PVH).

INTERVENTIONS

We treated the patient with diuretics and fosinopril, and also steroids and thalidomide for his MPN/MF.

OUTCOMES

Two weeks later, the pulmonary artery pressure (PAP) was remarkably decreased (PASP = 53.1 mm Hg by UCG, mean PAP = 21 mm Hg by right cardiac catheterization). Within 2 years' follow-up, his circulatory state and hematological state remained stable.

LESSONS

It is often difficult to define the cause of PH, but it is important for making the appropriate treatment at the same time.

Hematologic disorders during essential hypertension

BACKGROUND

Besides the traditional risk factors, hematological changes may be involved in the development of arterial hypertension and in its pathogenesis.

METHODS

The study, conducted on a sample of 545 subjects, 215 with hypertension and 330 witnesses, were evaluated for peripheral blood parameters in western Algeria; Logistic regression analysis was used to predict hypertension with hematological parameters.

RESULTS

The characters studied related significantly; lower red blood cell levels have a three-and-a-half-fold risk of developing hypertension compared to those who have normal red blood cell counts (OR = 3.64, 95% CI = 1.37-9.65, p < 0.05). Subjects who have mean corpuscular volume rate below 80 fl are more exposed to hypertension (OR = 13.58, 95% CI = 4.68-39.41, p = 0.000). The mean corpuscular hemoglobin concentration reveals that subjects who have a lower than normal (<27 pg) are once less exposed to hypertension (OR = 0.04, 95% CI = 0.01-0.13, p = 0.000). Subjects who have lower platelet count than normal are twelve times more exposed to hypertension (OR = 12.13, 95% CI = 1.45-101.18, P = 0.021). Finally, the increase in sedimentation rate at one hour increases the risk of hypertension by 56.63 times compared to subjects with normal sedimentation rate (OR = 56.63, 95% CI = 3.37-597.33, P = 0.001).

CONCLUSIONS

Hematological profile associated with essential hypertension retained Red blood cells ratio, mean corpuscular volume, mean corpuscular hemoglobin concentration, platelet ratio, and sedimentation rate at one hour.

Targeting IL-17 attenuates hypoxia-induced pulmonary hypertension through downregulation of β-catenin

BACKGROUND

The role of interleukin 17 (IL-17) in hypoxic pulmonary hypertension (HPH) remains unclear. This study is designed to explore whether IL-17 is a potential target for HPH treatment.

METHODS

Clinic samples from the lung tissue and serum were obtained from qualified patients. Western blotting, immunohistochemistry and/or ELISA were used to measure the expression of relevant proteins. HPH models were established in C57BL/6 wild-type (WT) and IL-17 ^-/- mice and were treated with exogenous recombinant mouse IL-17 (rmIL-17) or an IL-17 neutralising antibody. Assays for cell proliferation, angiogenesis and adhesion were employed to analyse the behaviours of human pulmonary arterial endothelial cells (HPAECs). A non-contact Transwell coculture model was used to evaluate intercellular interactions.

RESULTS

Expression of IL-17 was increased in lung tissue of both patients with bronchiectasis/COPD-associated PH and HPH mouse model. Compared with WT mice, IL-17 ^-/- mice had attenuated HPH, whereas administration of rmIL-17 aggravated HPH. In vitro, recombinant human IL-17 (rhIL-17) promoted proliferation, angiogenesis and adhesion in HPAECs through upregulation of Wnt3a/β-catenin/CyclinD1 pathway, and siRNA-mediated knockdown of β-catenin almost completely reversed this IL-17-mediated phenomena. IL-17 promoted the proliferation but not the migration of human pulmonary arterial smooth muscle cells (HPASMCs) cocultured with HPAECs under both normoxia and hypoxia, but IL-17 had no direct effect on proliferation and migration of HPASMCs. Blockade of IL-17 with a neutralising antibody attenuated HPH in WT mice.

CONCLUSIONS

IL-17 contributes to the pathogenesis of HPH through upregulation of β-catenin expression. Targeting IL-17 might provide potential benefits for alternative therapeutic strategies for HPH.

Comprehensive Evaluation of Right Heart Performance and Pulmonary Hemodynamics in Neonatal Pulmonary Hypertension : Evaluation of cardiopulmonary performance in neonatal pulmonary hypertension

PURPOSE OF REVIEW

Pulmonary hypertension is characterized by an elevation of pulmonary artery pressures and prolonged exposure of the right ventricle to high afterload that collectively contribute to morbidity and mortality in both the term and preterm infants. This review summarizes the pathogenesis, etiologies, and hemodynamic profiles of the conditions that result in pulmonary hypertension in neonates. We explore the application of echocardiographic techniques for the assessment of right ventricular performance and pulmonary hemodynamics that enhance and guide the diagnosis and management strategies in neonates.

RECENT FINDINGS

Clinical assessments based on the determinants of mean pulmonary artery pressures (pulmonary vascular resistance, pulmonary blood flow, and pulmonary capillary wedge pressure) provide a physiologic approach in determining the acute and chronic etiologies of pulmonary hypertension in neonates. In addition, advances in neonatal echocardiography now afford the capability to obtain quantitative information that often precedes the qualitative information acquired by conventional methods and also provide sensitive markers of right ventricle performance for prognostic information based on the determinants of mean pulmonary artery pressures. Neonatal pulmonary hypertension represents a physiologic spectrum that accounts for the variance in clinical presentation and response to therapies. Physiology-based approaches to etiological identification, coupled with the emerging echocardiographic methods for the assessment of pulmonary hypertension in neonates will likely help to identify cardiovascular compromise earlier, guide therapeutic intervention, monitor therapeutic effectiveness, and improve overall outcome.

Comparison of the Factors Influencing Pulmonary Arterial Pressure in Smoker and Non-smoker COPD Patients with Pulmonary Hypertension

BACKGROUND

There are several prognostic factors in patients with Chronic Obstructive Pulmonary Disease (COPD) that include Forced expiratory volume in one second (FEV1), Body Mass Index (BMI), dyspnea severity, exercise capacity and Pulmonary Hypertension (PH). PH is one of the most important factors. PH pathogenesis in patients with COPD has not been clarified thoroughly and factors such as alveolar hypoxemia, polycythemia, acidosis and pulmonary vessels obstruction have been suggested. The authors assessed some of these contributing factors in smoker and non-smoker patients with COPD.

MATERIALS AND METHODS

This comparative-descriptive study included COPD patients suspected to have cor pulmonale without exacerbation in the last four weeks. Echocardiographic evaluation of Pulmonary Arterial Pressure (PAP) was done and Pulmonary Hypertension (PH) was defined as systolic Pulmonary Arterial Pressure (PAP) greater than 40 mmHg. Complete Blood Count (CBC) and Arterial Blood Gas (ABG) were also studied in all patients.

RESULTS

Echocardiography was done for 142 patients who were suspected to have PH and 110 patients had measurable PAP. All of the patients were in stage II - IV of COPD according to GOLD criteria. 90 patients had PH of which 47 were smokers and 43 were non-smokers. In smoker patients, significant correlation between PAP and PaO₂ was seen (r=-0.291, p-value=0.047). But in non-smoker patients, this correlation was absent. A significant correlation between PAP and FEV1 (r=-0.341, P value=0.025) was seen in non-smoker patients. This correlation was absent in smoker patients. There was no correlation between PAP and hemoglobin, hemoglobin and FEV, and also PaO₂ and FEV1 in smoker and non-smoker COPD patients.

CONCLUSION

In non-smoker patients with COPD, degree of pulmonary parenchymal lesions and bronchial obliteration plays a more important role than hypoxia in the pathogenesis of pulmonary hypertension.

Usefulness of Red Cell Width Distribution (RDW) in the Assessment of Children with Pulmonary Arterial Hypertension (PAH)

Red cell width distribution (RDW) is known to be a prognostic marker in adults with pulmonary hypertension. The value of this test in the pulmonary arterial hypertension (PAH) pediatric population was not yet established. The aim of the study was to evaluate the prognostic value of RDW in children with PAH and utility of this parameter in the management. Data were collected retrospectively in 61 patients with PAH confirmed by right heart catheterization. RDW was measured at diagnosis, 3 and 12 months after initial therapy, during and after deterioration if occurred. Results were compared with NTproBNP, WHO-FC and oxygen blood saturation. Mean RDW at baseline was 15.3 ± 2.4% (12.1-24.4, median 14.7%) and was elevated in 29 patients (47%). There were no significant difference in clinical status, NTproBNP and hemodynamic parameters among patient with normal and elevated RDW at diagnosis. Poor negative correlation with SaO₂ and SvO₂ was shown. After 3 and 12 months of treatment no significant change of RDW level was found despite of statistically significant improvement of WHO-FC and decrease of NTproBNP level (NS). Episodes of clinical deterioration weren't connected with change of RDW level (16 vs. 15.6% NS). Kaplan-Meier analysis did not show differences in prognosis between patients with normal and elevated RDW. Elevation of RDW was not associated with any measured parameters. Prognostic value of RDW in the pediatric PAH population was not confirmed. Usefulness of RDW in management in PAH pediatric population is limited and required further studies.

New cases of Glucose-6-Phosphate Dehydrogenase deficiency in Pulmonary Arterial Hypertension

Pulmonary Arterial Hypertension (PAH) is a fatal disorder with limited treatment options and reduced life expectancy after diagnosis. Complex genetic backgrounds in PAH complicates identification of causative mutations that is essential for an understanding of the disease diagnostics and etiology especially for idiopathic PAH (iPAH). Hemolysis has been implicated as contributing to the pathobiology of PAH. Glucose-6-Phosphate Dehydrogenase (G6PD) expression and activity define erythrocyte's antioxidant capacity, and its decrease contributes to erythrocyte fragility. As G6PD deficiency was previously reported in a limited number of PAH cases, we tested whether iPAH patients exhibit underlying G6PD alterations in erythrocytes. A cohort of 22 PAH patients and 8 non-PAH patients were recruited for this study. DNA isolated from Peripheral Blood Mononuclear Cells (PBMC) was used for detection of mutations in the coding region of the G6PD gene. RNA isolated from PBMC was used for determination of G6PD mRNA expression level. G6PD activity was measured in Red Blood Cell (RBC) pellets. Three patients had missense mutations in G6PD (Val291Met, Asn126Asp, Asp194Glu), however, only one mutation (Val291Met) results in a severe G6PD deficiency. A single patient with mutation (Asn126Asp) showed a 21% decrease in G6PD activity, two subjects showed G6PD deficiency without mutations, and one patient had a decreased level of G6PD mRNA and reduced enzyme levels. This study demonstrates that a moderate decrease in G6PD activity is associated with PAH. Screening for G6PD activity and mutations in the G6PD gene may provide early detection of individuals predisposed to PAH.

The Hepcidin/Ferroportin axis modulates proliferation of pulmonary artery smooth muscle cells

Studies were undertaken to examine any role for the hepcidin/ferroportin axis in proliferative responses of human pulmonary artery smooth muscle cells (hPASMCs). Entirely novel findings have demonstrated the presence of ferroportin in hPASMCs. Hepcidin treatment caused increased proliferation of these cells most likely by binding ferroportin resulting in internalisation and cellular iron retention. Cellular iron content increased with hepcidin treatment. Stabilisation of ferroportin expression and activity via intervention with the therapeutic monoclonal antibody LY2928057 reversed proliferation and cellular iron accumulation. Additionally, IL-6 treatment was found to enhance proliferation and iron accumulation in hPASMCs; intervention with LY2928057 prevented this response. IL-6 was also found to increase hepcidin transcription and release from hPASMCs suggesting a potential autocrine response. Hepcidin or IL-6 mediated iron accumulation contributes to proliferation in hPASMCs; ferroportin mediated cellular iron excretion limits proliferation. Haemoglobin also caused proliferation of hPASMCs; in other novel findings, CD163, the haemoglobin/haptoglobin receptor, was found on these cells and offers a means for cellular uptake of iron via haemoglobin. Il-6 was also found to modulate CD163 on these cells. These data contribute to a better understanding of how disrupted iron homeostasis may induce vascular remodelling, such as in pulmonary arterial hypertension.

Myeloid-Derived Suppressor Cells and Pulmonary Hypertension

Myeloid–derived suppressor cells (MDSCs) comprised a heterogeneous subset of bone marrow–derived myeloid cells, best studied in cancer research, that are increasingly implicated in the pathogenesis of pulmonary vascular remodeling and the development of pulmonary hypertension. Stem cell transplantation represents one extreme interventional strategy for ablating the myeloid compartment but poses a number of translational challenges. There remains an outstanding need for additional therapeutic targets to impact MDSC function, including the potential to alter interactions with innate and adaptive immune subsets, or alternatively, alter trafficking receptors, metabolic pathways, and transcription factor signaling with readily available and safe drugs. In this review, we summarize the current literature on the role of myeloid cells in the development of pulmonary hypertension, first in pulmonary circulation changes associated with myelodysplastic syndromes, and then by examining intrinsic myeloid cell changes that contribute to disease progression in pulmonary hypertension. We then outline several tractable targets and pathways relevant to pulmonary hypertension via MDSC regulation. Identifying these MDSC-regulated effectors is part of an ongoing effort to impact the field of pulmonary hypertension research through identification of myeloid compartment-specific therapeutic applications in the treatment of pulmonary vasculopathies.

Pulmonary Arterial Hypertension: Iron Matters

The interplay between iron and oxygen is longstanding and central to all aerobic life. Tight regulation of these interactions including homeostatic regulation of iron utilization ensures safe usage of this limited resource. However, when control is lost adverse events can ensue, which are known to contribute to an array of disease processes. Recently, associations between disrupted iron homeostasis and pulmonary artery hypertension (PAH) have been described with the suggestion that there is a contributory link with disease. This review provides a background for iron regulation in humans, describes PAH classifications, and discusses emerging literature, which suggests a role for disrupted iron homeostatic control in various sub-types of PAH, including a role for decompartmentalization of hemoglobin. Finally, the potential for therapeutic options to restore iron homeostatic balance in PAH are discussed.

Inflammatory Macrophage Expansion in Pulmonary Hypertension Depends upon Mobilization of Blood-Borne Monocytes

Pulmonary inflammation, which is characterized by the presence of perivascular macrophages, has been proposed as a key pathogenic driver of pulmonary hypertension (PH), a vascular disease with increasing global significance. However, the mechanisms of expansion of lung macrophages and the role of blood-borne monocytes in PH are poorly understood. Using multicolor flow cytometric analysis of blood in mouse and rat models of PH and patients with PH, an increase in blood monocytes was observed. In parallel, lung tissue displayed increased chemokine transcript expression, including those responsible for monocyte recruitment, such as Ccl2 and Cx₃cl1, accompanied by an expansion of interstitial lung macrophages. These data indicate that blood monocytes are recruited to lung perivascular spaces and differentiate into inflammatory macrophages. Correspondingly, parabiosis between congenically different hypoxic mice demonstrated that most interstitial macrophages originated from blood monocytes. To define the actions of these cells in PH in vivo, we reduced blood monocyte numbers via genetic deficiency of cx₃cr1 or ccr2 in chronically hypoxic male mice and by pharmacologic inhibition of Cx₃cl1 in monocrotaline-exposed rats. Both models exhibited decreased inflammatory blood monocytes, as well as interstitial macrophages, leading to a substantial decrease in arteriolar remodeling but with a less robust hemodynamic effect. This study defines a direct mechanism by which interstitial macrophages expand in PH. It also demonstrates a pathway for pulmonary vascular remodeling in PH that depends upon interstitial macrophage-dependent inflammation yet is dissociated, at least in part, from hemodynamic consequences, thus offering guidance on future anti-inflammatory therapeutic strategies in this disease.

The role of extracellular matrix stiffness in megakaryocyte and platelet development and function

The extracellular matrix (ECM) is a key acellular structure in constant remodeling to provide tissue cohesion and rigidity. Deregulation of the balance between matrix deposition, degradation, and crosslinking results in fibrosis. Bone marrow fibrosis (BMF) is associated with several malignant and nonmalignant pathologies severely affecting blood cell production. BMF results from abnormal deposition of collagen fibers and enhanced lysyl oxidase-mediated ECM crosslinking within the marrow, thereby increasing marrow stiffness. Bone marrow stiffness has been recently recognized as an important regulator of blood cell development, notably by modifying the fate and differentiation process of hematopoietic or mesenchymal stem cells. This review surveys the different components of the ECM and their influence on stem cell development, with a focus on the impact of the ECM composition and stiffness on the megakaryocytic lineage in health and disease. Megakaryocyte maturation and the biogenesis of their progeny, the platelets, are thought to respond to environmental mechanical forces through a number of mechanosensors, including integrins and mechanosensitive ion channels, reviewed here.

A comparative cross-sectional study of some hematological parameters of hypertensive and normotensive individuals at the university of Gondar hospital, Northwest Ethiopia

Background

Hypertension is a major health problem worldwide. It can lead to cardiovascular disease and also leads to functional disturbances including hematological parameters. The abnormalities of haematological parameters may enhance an end-organ damage. Therefore, the aim of this study was to assess some hematological parameters of hypertensive individuals in comparison with normotensive individuals at University of Gondar hospital, northwest Ethiopia.

Methods

A cross sectional comparative study was conducted from October to November 2015 on a total of 126 hypertensive and 126 normotensive individuals at University of Gondar Hospital. All participants after taking informed consent were interviewed for detailed history and 3 ml of blood was collected for hematological test analysis. Independent t-test and the Mann Whitney u-test were used to find out significant difference and Pearson’s and Spearman’s correlation were used for correlation test. P values less than 0.05 was considered the level of significance.

Result

From a total of 252 study subjects, about 67.5% were females. The mean age of study subjects was 50.3 ± 11 years for hypertensive individuals and 49.8 ± 11.6 years for normotensive individuals with range of 18–65 years. In the present study, the median (IQR) value of WBC, RBC, Hgb, HCT, MCV and the mean value of MCHC, RDW, MPV and PDW were significantly higher in hypertensive group compared to apparently healthy normotensive groups. Additionally, WBC, RBC, Hgb, HCT and PLT showed statistically significant positive correlations with blood pressure indices. Platelet count and MCH did not show statistically significant difference between the two groups.

Conclusion

Hypertension has impact on hematological parameters. In this study, the mean and median values of haematological parameters in hypertensive individuals were significantly different compared to apparently healthy normotensive individuals. Hence, hematological parameters can be used to monitor the prognosis of the disease and manage hypertensive related complications, and it is important to assess hematological parameters for hypertensive individuals which may help to prevent complications associated hematological disorders.

Electronic supplementary material

The online version of this article (doi: 10.1186/s12878-017-0093-9) contains supplementary material, which is available to authorized users.

Origin and production of inflammatory perivascular macrophages in pulmonary hypertension

Myeloid cells, including monocytes and macrophages participate in steady state immune homeostasis and help mount the adaptive immune response during infection. The function and production of these cells in sterile inflammation, such as pulmonary hypertension (PH), is understudied. Emerging data indicate that pulmonary inflammation mediated by lung perivascular macrophages is a key pathogenic driver of pulmonary remodeling leading to increased right ventricular systolic pressure (RVSP). However, the origin of these macrophages in pulmonary inflammation is unknown. Inflammatory monocytes, the precursors of pathogenic macrophages, are derived from hematopoietic stem and progenitor cells (HSPC) in the bone marrow and spleen during acute and chronic inflammation. Understanding the role of these organs in monocytopoiesis, and the mechanisms of HSPC proliferation and differentiation in PH are important to discover therapeutic targets curbing inflammation. This review will summarize the current limited knowledge of the origin of lung macrophage subsets and over-production of inflammatory monocytes in PH.