Pulmonary hypertension associated with thalassemia syndromes

Pulmonary hypertension aetiologies in different parts of the world

Pulmonary hypertension is a serious condition characterised by elevated blood pressure in the pulmonary arteries, caused by various aetiologies and via different pathological processes. Over the past seventy years, our understanding and management of this disorder have greatly improved, resulting in increased diagnosis and effective clinical management. Current epidemiological estimates are challenged by the increased awareness of this condition and the changing definitions and classification systems. The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) has also shown temporal changes in the epidemiology of pulmonary hypertension over the last thirty years, contributing to regional variations in prevalence and incidence. This review explores the complexities of global and regional variations in different types of pulmonary hypertension reported through many registries, databases and regional studies. Although these tools can help estimate prevalence and incidences, they may also underestimate the actual number of cases due to the continuously changing understanding of the condition and increase awareness globally. Therefore, continued research, international collaboration, and standardised data collection are essential for achieving a more accurate global view of pulmonary hypertension and developing effective management strategies for this serious condition that significantly impacts general health.

The predicting formula and scoring system for cardiac iron overload for thalassaemia children: Study from a middle-income country

Magnetic resonance imaging T2* screening is the gold standard for detecting cardiac iron overload in thalassemia, but its implementation in Indonesia is limited by the high costs. A predicting formula and scoring system based on low-cost investigations is needed. This cross-sectional study was conducted among thalassemia aged 6-18 years at Rumah Sakit Anak dan Bunda RSAB Harapan Kita Indonesia, during October 2017 to April 2019. All subjects were scheduled for clinical examination, laboratory tests, ECGs, echocardiography, tissue Doppler imaging, and MRIT2*. Multivariate logistic regression was used to identify the formula, simplifying to a scoring system, and risk classification for myocardial iron overload using odds ratio (OR) and 95% confidence interval (CI). Significance was set as p<0,05. We recruited 80 children, of those, 8 (10%) were classified as cardiac iron overload based on MRI T2* screening. Multivariate logistic regression showed determinant factors for cardiac iron overload were hemoglobin (95% CI:1.92-369.14), reticulocyte (95% CI:1.14-232.33), mitral deceleration time (DT) (95% CI:1.80-810.62,), and tricuspid regurgitation (TR Vmax) (95% CI:1.87-1942.56) with aOR of 26.65, 14.27, 38.22, and 60.27 respectively. The formula for cardiac iron overload was decided as 9.32 + 3.28 (Hb) + 2.9 (reticulocyte) + 3.64 (DT) + 4.1 (TR Vmax). A scoring system was defined by simplifying the formula of Hb ≤ 8.2 g/L, reticulocyte ≤0.33%, DT ≤ 114.5 cm/s, and TR Vmax ≥ 2.37 m/s were given a score of 1, while others were assigned 0. Total scores of 0 or 1, 2 and 3 or 4 were categorized as low, moderate, and high risk for iron cardiac overload. The cardiac iron overload formula was 9.32 + 3.28 (Hb) + 2.9 (reticulocyte) + 3.64 (DT) + 4.1 (TR Vmax). Variables of Hb ≤ 8.2 g/L, reticulocyte ≤0.33%, DT ≤ 114.5 cm/s, and TR Vmax ≥ 2.37 m/s were given a score of 1, while others were assigned 0. Total scores of 0 or 1, 2, and 3 or 4 were categorized as low, moderate, and high risk for iron cardiac overload.

A moonlighting job for α-globin in blood vessels

ABSTRACT

Red blood cells express high levels of hemoglobin A tetramer (α2β2) to facilitate oxygen transport. Hemoglobin subunits and related proteins are also expressed at lower levels in other tissues across the animal kingdom. Physiological functions for most nonerythroid globins likely derive from their ability to catalyze reduction-oxidation (redox) reactions via electron transfer through heme-associated iron. An interesting example is illustrated by the recent discovery that α-globin without β-globin is expressed in some arteriolar endothelial cells (ECs). α-globin binds EC nitric oxide (NO) synthase (eNOS) and degrades its enzymatic product NO, a potent vasodilator. Thus, depletion of α-globin in ECs or inhibition of its association with eNOS causes arteriolar relaxation and lowering of blood pressure in mice. Some of these findings have been replicated in isolated human blood vessels, and genetic studies are tractable in populations in which α-thalassemia alleles are prevalent. Two small studies identified associations between loss of α-globin genes in humans and NO-regulated vascular responses elicited by local hypoxia-induced blood flow or thermal stimulation. In a few larger population-based studies, no associations were detected between loss of α-globin genes and blood pressure, ischemic stroke, or pulmonary hypertension. In contrast, a significant positive association between α-globin gene copy number and kidney disease was detected in an African American cohort. Further studies are required to define comprehensively the expression of α-globin in different vascular beds and ascertain their overall impact on normal and pathological vascular physiology.

The Discovery of Selective Protein Arginine Methyltransferase 5 Inhibitors in the Management of β-Thalassemia through Computational Methods

β-Thalassemia is an inherited genetic disorder associated with β-globin chain synthesis, which ultimately becomes anemia. Adenosine-2,3-dialdehyde, by inhibiting arginine methyl transferase 5 (PRMT5), can induce fetal hemoglobin (HbF) levels. Hence, the materialization of PRMT5 inhibitors is considered a promising therapy in the management of β-thalassemia. This study conducted a virtual screening of certain compounds similar to 5'-deoxy-5'methyladenosine (3XV) using the PubChem database. The top 10 compounds were chosen based on the best docking scores, while their interactions with the PRMT5 active site were analyzed. Further, the top two compounds demonstrating the lowest binding energy were subjected to drug-likeness analysis and pharmacokinetic property predictions, followed by molecular dynamics simulation studies. Based on the molecular mechanics Poisson-Boltzmann surface area (MM-PBSA) score and molecular interactions, (3R,4S)-2-(6-aminopurin-9-yl)-5-[(4-ethylcyclohexyl)sulfanylmethyl]oxolane-3,4-diol (TOP1) and 2-(6-Aminopurin-9-yl)-5-[(6-aminopurin-9-yl)methylsulfanylmethyl]oxolane-3,4-diol (TOP2) were identified as potential hit compounds, while TOP1 exhibited higher binding affinity and stabler binding capabilities than TOP2 during molecular dynamics simulation (MDS) analysis. Taken together, the outcomes of our study could aid researchers in identifying promising PRMT5 inhibitors. Moreover, further investigations through in vivo and in vitro experiments would unquestionably confirm that this compound could be employed as a therapeutic drug in the management of β-thalassemia.

Macitentan Administration for Pulmonary Hypertension Due to β-thalassemia with Multiple Organ Failure

A 51-year-old Thai woman diagnosed with β-thalassemia underwent regular blood transfusion and iron-chelating therapy. However, after voluntarily discontinuing treatment, the patient developed progressive dyspnea and was diagnosed with pulmonary hypertension following right heart catheterization. Despite resuming blood transfusions, her condition did not improve. Because the patient had a history of multiple organ failure, curative treatment for β-thalassemia was not feasible, and macitentan was administered. Despite experiencing hypotension as an adverse event, her condition remained stable during macitentan treatment. Thus, macitentan may be well tolerated in patients with pulmonary hypertension caused by β-thalassemia with multiple organ dysfunction.

The Prevalence of Pulmonary Arterial Hypertension in Patients with Beta Thalassemia Major

Pulmonary arterial hypertension (PAH) remains a concern in patients with Beta thalassemia major (TM). However, this study aims to investigate the prevalence of PAH in TM patients in Kerman City placed in the south of Iran. In this cross-sectional study on 271 IranianBeta-thalassemia patients (mean age 19.8 ± 7.9 in the range 10-60), Age, sex, weekly deferral taking, the number of blood transfusion in a month, and last echocardiography report data was gathered from every patient's file. SPSS for Windows (version 21) was used for analysis. According to the results, the prevalence of PAH was 10.3% (28 patients). PAH had significant associations with weekly deferral consumption (P = 0.028), ferritin serum level (P = 0.001), and ejection fraction (EF) (P = 0.001). PAH is positively associated with deferral consumption and is negatively associated with EF (respectively, P = 0.031, P = 0.001). It is very important to consider prevention and treatment for decreasing the mortality and morbidity of PAH patients in health planning and policy.

Extramedullary hematopoiesis in ribs and severe pulmonary hypertension disease following intermediate beta-thalassemia: a case report

BACKGROUND

Thalassemia is a type of congenital hemoglobinopathy that falls into the category of hemolytic anemias. Extramedullary hematopoiesis is a complication of this disease, which is a mechanism to compensate for chronic anemia in these patients, and imaging is the best diagnostic method.

CASE REPORT

In this report, a 36-year-old Caucasian female patient with intermediate beta thalassemia is presented who, at the time of referral, complained of exacerbated shortness of breath. Imaging showed diffuse expansion masses with soft tissue components in the ribs of both hemithoraxes, leading to the diagnosis of extramedullary hematopoiesis.

CONCLUSION

Extramedullary hematopoiesis in the ribs is an uncommon finding in patients with thalassemia and is a sign of the severity of the disease and a poor prognostic factor that might be preventable if blood transfusion begins at younger ages.

In Silico Molecular Docking and Dynamics Simulation Analysis of Potential Histone Lysine Methyl Transferase Inhibitors for Managing β-Thalassemia

A decreased hemoglobin synthesis is contemplated as a pathological indication of β-thalassemia. Recent studies show that EPZ035544 from Epizyme could induce fetal hemoglobin (HbF) levels due to its proven capability to inhibit euchromatin histone lysine methyl transferase (EHMT2). Therefore, the development of EHMT2 inhibitors is considered promising in managing β-thalassemia. Our strategy to find novel compounds that are EHMT2 inhibitors relies on the virtual screening of ligands that have a structural similarity to N2-[4-methoxy-3-(2,3,4,7-tetrahydro-1H-azepin-5-yl) phenyl]-N4,6-dimethyl-pyrimidine-2,4-diamine (F80) using the PubChem database. In silico docking studies using Autodock Vina were employed to screen a library of 985 compounds and evaluate their binding ability with EHMT2. The selection of hit compounds was based on the docking score and mode of interaction with the protein. The top two ranked compounds were selected for further investigations, including pharmacokinetic properties analysis and molecular dynamics simulations (MDS). Based on the obtained docking score and interaction analysis, N-(4-methoxy-3-methylphenyl)-4,6-diphenylpyrimidin-2-amine (TP1) and 2-N-[4-methoxy-3-(5-methoxy-3H-indol-2-yl)phenyl]-4-N,6-dimethylpyrimidine-2,4-diamine (TP2) were found to be promising candidates, and TP1 exhibited better stability in the MDS study compared to TP2. In summary, our approach helps identify potential EHMT2 inhibitors, and further validation using in vitro and in vivo experiments could certainly enable this molecule to be used as a therapeutic drug in managing β-thalassemia disease.

Pulmonary function in patients with transfusion-dependent thalassemia and its associations with iron overload

In patients with transfusion-dependent thalassemia (TDT), pulmonary function impairment has been reported but data are conflicting. Moreover, it remains unclear whether pulmonary dysfunction is associated with iron overload. This study aimed to evaluate the pulmonary function in patients with TDT and to investigate the associations between pulmonary dysfunction and iron overload. It was a retrospective observational study. 101 patients with TDT were recruited for lung function tests. The most recent ferritin levels (pmol/L) and the magnetic resonance imaging (MRI) measurements of the myocardial and liver iron status, as measured by heart and liver T2* relaxation time (millisecond, ms) respectively, were retrieved from the computerized medical records. Only data within 12 months from the lung function measurement were included in the analysis. The serum ferritin, and the cardiac and liver T2* relaxation time were the surrogate indexes of body iron content. The threshold of abnormality in lung function was defined as under 80% of the predicted value. 101 subjects were recruited with a mean age of 25.1 years (standard deviation (SD) 7.9 years). Thirty-eight (38%) and five (5%) demonstrated restrictive and obstructive lung function deficits, respectively. A weak correlation of FVC %Predicted and TLC %Predicted with MRI myocardial T2* relaxation time (rho = 0.32, p = 0.03 and rho = 0.33, p = 0.03 respectively) was observed. By logistic regression, MRI cardiac T2* relaxation time was negatively associated with restrictive lung function deficit (B - 0.06; SE 0.03; Odds ratio 0.94; 95% confidence interval (CI) 0.89-0.99; p = 0.023) after adjusting for age, sex and body mass index. Restrictive pulmonary function deficit was commonly observed in patients with TDT, and the severity potentially correlates with myocardial iron content. Monitoring of lung function in this group of patients, particularly for those with iron overload, is important.

Cardiovascular Complications in β-Thalassemia: Getting to the Heart of It

Beta thalassemia is an inherited disorder resulting in abnormal or decreased production of hemoglobin, leading to hemolysis and chronic anemia. The long-term complications can affect multiple organ systems, namely the liver, heart, and endocrine. Myocardial iron overload is a common finding in β-thalassemia. As a result, different cardiovascular complications in the form of cardiomyopathy, pulmonary hypertension, arrhythmias, and vasculopathies can occur, and in extreme cases, sudden cardiac death. Each of these complications pertains to underlying etiologies and risk factors, which highlights the importance of early diagnosis and prevention. In this review, we will discuss different types of cardiovascular complications that can manifest in patients with β-thalassemia, in addition to the current diagnostic modalities, preventive and treatment modalities for these complications.

Non-Transfusion-Dependent Thalassemia: A Panoramic Review

Non-transfusion-dependent thalassemia (NTDT) has been considered less severe than its transfusion-dependent variants. The most common forms of NTDT include β-thalassemia intermedia, hemoglobin E/beta thalassemia, and hemoglobin H disease. Patients with NTDT develop several clinical complications, despite their regular transfusion independence. Ineffective erythropoiesis, iron overload, and hypercoagulability are pathophysiological factors that lead to morbidities in these patients. Therefore, an early and accurate diagnosis of NTDT is essential to ascertaining early interventions. Currently, several conventional management options are available, with guidelines suggested by the Thalassemia International Federation, and novel therapies are being developed in light of the advancement of the understanding of this disease. This review aimed to increase clinicians’ awareness of NTDT, from its basic medical definition and genetics to its pathophysiology. Specific complications to NTDT were reviewed, along with the risk factors for its development. The indications of different therapeutic options were outlined, and recent advancements were reviewed.

Iron overload, oxidative stress and vascular dysfunction: Evidences from clinical studies and animal models

Although iron is a metal involved in many in vital processes due to its redox capacity, body iron overloads lead to tissue damage, including the cardiovascular system. While cardiomyopathy was the focus since the 1960s, the impact on the vasculature was comparatively neglected for about 40 years, when clinical studies correlating iron overload, oxidative stress, endothelial dysfunction, arterial stiffness and atherosclerosis reinforced an "iron hypothesis". Due to controversial results from some epidemiological studies investigating atherosclerotic events and iron levels, well-controlled trials and animal studies provided essential data about the influence of iron, per se, on the vasculature. As a result, the pathophysiology of vascular dysfunction in iron overload have been revisited. This review summarizes the knowledge obtained from epidemiological studies, animal models and "in vitro" cellular systems in recent decades, highlighting a more harmful than innocent role of iron excess for the vascular homeostasis, which supports our proposal to hereafter denominate "iron overload vasculopathy". Additionally, evidence-based therapeutic targets are pointed out to be tested in pre-clinical research that may be useful in cardiovascular protection for patients with iron overload syndromes.

Assessment of Cardiac Functions and Arrhythmia in Children with Beta-Thalassemia Major and Beta-Thalassemia Intermedia

BACKGROUND: Heart disease is a major complication in thalassemic patients. Heart injuries in iron overload cases include arrhythmia, pulmonary hypertension, systolic/diastolic dysfunction, and heart failure. AIM: This study aimed to assess cardiac functions and arrhythmia in children with β-thalassemia major (TM) and β-thalassemia intermedia (TI) and its relation to cardiac iron overload. METHODS: Thirty β-TM patients and 30 β-TI patients were evaluated using echocardiography and 24-h ambulatory electrocardiogram monitoring (Holter). Among these patients, 15 β-TM and 15 β-TI patients were evaluated using cardiac magnetic resonance imaging T2* by single breath-hold multi-echo technique. RESULTS: Arrhythmia was detected significantly more in β-TM patients than β-TI (p = 0.049). Nine (30%) β-TM and five (16.6%) β-TI patients had Sinus tachycardia. Two (6.7%) β-TM patients compared to one (3.33%) β-TI patient had supraventricular tachycardia runs. Three (10%) β-TM and one (3.33%) β-TI patient had extreme sinus tachycardia. Two (3.3%) β-TI patients had sinus bradycardia, while two (3.3%) β-TM patients had incomplete Right bundle branch block. Regarding echo parameters: Isovolumic relaxation time (IVRT), Left ventricle myocardial performance index (MPI LV), Right ventricle myocardial performance index (MPI RV) and end systolic pulmonary artery pressure, were significantly higher in β-TM than TI group (p < 0.05). Fractional shortening, Ejection fraction were significantly lower in β-TM than TI group (p < 0.001). A statistically significant negative correlation was found between cardiac T2* and each of (IVRT, MPI LV, MPI RV) (p ˂ 0.05). CONCLUSION: Arrhythmias are more common in the β-TM group. Systolic, diastolic dysfunction and high pulmonary pressure are more prevalent in TM than in TI. Global myocardial performance is more impaired in TM than in TI patients. Iron overload has a deleterious effect on cardiac function.

Signaling Integration of Hydrogen Sulfide and Iron on Cellular Functions

Significance: Hydrogen sulfide (H₂S) is an endogenous signaling molecule, regulating numerous physiological functions from vasorelaxation to neuromodulation. Iron is a well-known bioactive metal ion, being the central component of hemoglobin for oxygen transportation and participating in biomolecule degradation, redox balance, and enzymatic actions. The interplay between H₂S and iron metabolisms and functions impacts significantly on the fate and wellness of different types of cells. Recent Advances: Iron level in vivo affects the production of H₂S via nonenzymatic reactions. On the contrary, H₂S quenches excessive iron inside the cells and regulates the redox status of iron. Critical Issues: Abnormal metabolisms of both iron and H₂S are associated with various conditions and diseases such as iron overload, anemia, oxidative stress, and cardiovascular and neurodegenerative diseases. The molecular mechanisms for the interactions between H₂S and iron are unsettled yet. Here we review signaling links of the production, metabolism, and their respective and integrative functions of H₂S and iron in normalcy and diseases. Future Directions: Physiological and pathophysiological importance of H₂S and iron as well as their therapeutic applications should be evaluated jointly, not separately. Future investigation should expand from iron-rich cells and tissues to the others, in which H₂S and iron interaction has not received due attention. Antioxid. Redox Signal. 36, 275-293.

Randomized Clinical and Biochemical Study Comparing the Effect of L-arginine and Sildenafil in Beta Thalassemia Major Children With High Tricuspid Regurgitant Jet Velocity

Background:

Pulmonary hypertension (PHT) is common in β-thalassemia patients due to hemolysis, iron overload and diminished nitric oxide (NO) levels. Biochemical markers can help to understand the pathophysiology and to introduce new therapies for this condition.

Aim:

This study aimed to evaluate the effectiveness of L-arginine and sildenafil in thalassemia children with PHT at both clinical and biochemical levels.

Methods and Results:

In a randomized controlled study, 60 β-thalassemia major children with PHT were divided into 3 equal groups; Control group (Conventional thalassemia and PHT management), L-arginine group (Conventional + Oral L-arginine 0.1 mg.kg−1 daily), and sildenafil group (Conventional + Oral sildenafil 0.25 mg.kg−1 two times a day) for 60 days. Tricuspid Regurgitant Jet Velocity (TRJV) with Doppler echocardiography along with serum levels of NO, asymmetric dimethylarginine (ADMA), interleukin 1-beta (IL-1β), E-selectin, and visfatin were followed-up at baseline, 30, and 60 days after treatment. Both drugs reduced the TRJV significantly. NO was significantly higher in both L-arginine and sildenafil groups after 60 days compared to baseline, while visfatin levels were lower. Only L-arginine reduced ADMA levels compared to baseline, while sildenafil did not. E-selectin and IL-1β levels did not change remarkably by both drugs. NO and TRJV showed significant negative correlations in both treatment groups.

Conclusion:

L-arginine and sildenafil could clinically ameliorate chronic PHT whereas, L-arginine showed superiority to sildenafil on some biochemical markers.

Murine models of sickle cell disease and beta-thalassemia demonstrate pulmonary hypertension with distinctive features

Sickle cell anemia and β-thalassemia intermedia are very different genetically determined hemoglobinopathies predisposing to pulmonary hypertension. The etiologies responsible for the associated development of pulmonary hypertension in both diseases are multi-factorial with extensive mechanistic contributors described. Both sickle cell anemia and β-thalassemia intermedia present with intra and extravascular hemolysis. And because sickle cell anemia and β-thalassemia intermedia share features of extravascular hemolysis, macrophage iron excess and anemia we sought to characterize the common features of the pulmonary hypertension phenotype, cardiac mechanics, and function as well as lung and right ventricular metabolism. Within the concept of iron, we have defined a unique pulmonary vascular iron accumulation in lungs of sickle cell anemia pulmonary hypertension patients at autopsy. This observation is unlike findings in idiopathic or other forms of pulmonary arterial hypertension. In this study, we hypothesized that a common pathophysiology would characterize the pulmonary hypertension phenotype in sickle cell anemia and β-thalassemia intermedia murine models. However, unlike sickle cell anemia, β-thalassemia is also a disease of dyserythropoiesis, with increased iron absorption and cellular iron extrusion. This process is mediated by high erythroferrone and low hepcidin levels as well as dysregulated iron transport due transferrin saturation, so there may be differences as well. Herein we describe common and divergent features of pulmonary hypertension in aged Berk-ss (sickle cell anemia) and Hbb^th/3+ (intermediate β-thalassemia) mice and suggest translational utility as proof-of-concept models to study pulmonary hypertension therapeutics specific to genetic anemias.

How does iron deposition modify the myocardium? A feature-tracking cardiac magnetic resonance study

Iron-overload cardiomyopathy is the principal cause of mortality in thalassemia. Via feature-tracking cardiac magnetic resonance (FT-CMR), we investigated alterations in cardiac deformation with the progression in myocardial iron overload (MIO). We enrolled 154 patients with thalassemia (50.64% male, mean age = 32.19 ± 9.79 years) referred for MIO assessment and 28 controls (50% male, mean age = 31.07 ± 4.35 years). Functional, strain, and T2* values were assessed in 4 study groups: no MIO (T2* > 20), mild-to-moderate MIO (T2* = 10-20), severe MIO (T2* < 10), and healthy controls. The recorded strain values were compared between the groups. The study groups were statistically significantly different vis-à-vis left ventricular (LV) global longitudinal strain (GLS) (F [3, 178] = 20.30), LV global radial strain (GRS) (F [3, 178] = 11.61), right ventricular (RV) GLS (F [3, 178]) = 5.32), RV global circumferential strain (GCS) (F [3, 178] = 26.02), and RVGRS (F [3, 178] = 16.86) (Ps < 0.005). The post hoc test revealed that LVGLS, RVGCS, and RVGRS were different between patients with thalassemia but without MIO and the control group (Ps < 0.001). A significant difference in LVGLS and LVGRS was detected between the T2* > 20 and 10 ≤ T2* ≤ 20 groups (Ps < 0.05). The multivariate logistic regression analysis depicted LVGRS as the most robust predictor of MIO (T2* ≤ 20) (odds ratio = 0.920, 95% CI 0.886 to 0.955), which predicted MIO with a cutoff point of 31.16% or less (sensitivity = 62% and specificity = 80.77%). Biventricular FT-CMR values are impaired in patients with thalassemia even without MIO. With MIO progression, LV strain values are the first ones to be undermined. Notably, functional CMR indices are jeopardized late, only after severe iron deposition.

Anemia at Altitude: Thalassemia, Sickle Cell Disease, and Other Inherited Anemias

DeLoughery, Thomas G. Anemia at altitude-thalassemia, sickle cell disease, and other inherited anemias. High Alt Med Biol. 22: 113-118, 2021.-Anemia due to any etiology is a common medical condition throughout the world. This article discusses the most common inherited anemia types-sickle cell disease and trait, thalassemia, hereditary spherocytosis, and glucose-6-phosphate dehydrogenase deficiency. The implications of anemia for travel at altitude are discussed, and suggestions for counsel and preparations for such travel are presented.

Luspatercept: A Gigantic Step in the Treatment of Transfusion-Dependent β-Thalassemia Patients-a Quick Review

INTRODUCTION

Some studies have indicated that the use of luspatercept may be a novel and efficient treatment for β-thalassemia patients. In this article, we aimed to review the current evidence related to luspatercept prescription and its clinical effectiveness in patients with β-thalassemia.

METHODS

PubMed, Web of Science, Scopus, Trip and CENTRAL were searched up to June 2020. The inclusion criteria were English-language articles that studied the effects of luspatercept on improving anemia severity in patients with β-thalassemia in a clinical setting.

RESULTS

The search strategy yielded 273 potentially relevant articles. After searching the databases, scanning of titles, abstracts and full texts for relevancy was performed to identify suitable articles. A total of 77 articles were confirmed for full text analysis. The estimated number of patients needed to treat (NNT) for luspatercept treatment, using data derived from conducted clinical trials, according to a reduction in transfusion need of ≥ 33% or ≥ 50 from baseline, during week 13-24/week 37-48/any 12- and 24-week intervals as outcomes, was 3-5 in patients with β-thalassemia.

CONCLUSION

Based on the conducted studies, the effectiveness of luspatercept on transfusion burden and hemoglobin levels was outstanding in β-thalassemia patients. Further large and well-designed clinical studies are needed to identify any unforeseen complications subsequent to use of luspatercept, particularly when used with other treatments with potentially serious adverse effects such as anti-osteoporotic and iron chelator agents.

Pulmonary thromboendarterectomy for pulmonary hypertension linked to thalassemia

This report supports the feasibility of pulmonary thromboendarterectomy in thalassemic patients, and highlights the need for a comprehensive evaluation of the cause of pulmonary hypertension prior to determining the likelihood of surgical cure.

Prediction of long-term survival in patients with transfusion-dependent hemoglobinopathies: Insights from cardiac imaging and ferritin

AIMS

The current study evaluated the association of echocardiography, cardiac magnetic resonance (CMR), and ferritin data with 10-year survival in thalassemia patients.

METHODS

Demographics, ferritin, echocardiography, and CMR parameters of stable consecutive thalassemia patients were prospectively collected.

RESULTS

In total, 75 patients (mean age 37 ± 11 years, 45% male) with thalassemia were included and dichotomized based on their survival status after a median follow-up period of 10.3 [9.6-10.9] years. Older age (HR: 1.071, p = 0.001), ferritin ≥2000 ng/ml (HR: 4.682, p = 0.007) and ≥1700 ng/ml (HR: 7.817, p = 0.002), elevated LV end-diastolic pressure (HR: 1.019, p = 0.044), TR Vmax >2.8 m/s (HR: 6.845, p = 0.005), and CMR T2∗ ≤20 msec (HR: 3.602, p = 0.043) and ≤34 msec (HR: 5.854, p = 0.026) were associated with increased all-cause mortality (primary endpoint). A baseline model including age was created and became more predictive of worse survival by adding TR Vmax >2.8 m/s instead of elevated LV end-diastolic pressure (C index 0.767 vs. 0.760, respectively), ferritin ≥1700 ng/ml instead of ≥2000 ng/ml (C index 0.890 vs. 0.807, respectively), or CMR T2∗≤34 msec instead of ≤20 msec (C index 0.845 vs. 0.839, respectively). Parameters associated with the combined endpoint of cardiac mortality/cardiac hospitalization (secondary endpoint) after adjusting for age were ferritin ≥1700 ng/ml (HR 3.770, p = 0.014), ratio E/A wave >2 (HR 3.565, p = 0.04), TR Vmax >2.8 m/s (HR 4.541, p = 0.049), CMR T2∗ ≤20 ms (HR 9.462, p = 0.001), and CMR T2∗ ≤34 ms (HR 11.735, p = 0.002). The model including age and T2∗ ≤34 ms instead of T2∗ ≤20 ms was more predictive of the secondary endpoint (C-index 0.844 vs 0.838, respectively).

CONCLUSIONS

In thalassemia patients, TR Vmax >2.8 m/s, ferritin ≥2000 ng/ml, and CMR T2∗ ≤20 ms were associated with worse long-term survival. In the current era of advanced chelation therapy, aiming for ferritin ≤1700 ng/ml and CMR T2∗ ≥34 ms may improve their prognosis.

Doppler-defined pulmonary hypertension in β-thalassemia major in Kurdistan, Iraq

Cardiopulmonary complications are among the most important complications of thalassemia major. Pulmonary hypertension is among these complications and studies addressing its frequency and associations in the latter disorder are sparse from Iraq. For this purpose a total 100 thalassemia major patients (≥ 8 years old) were enrolled from a main thalassemia center in Kurdistan, Northern Iraq. All patients had a full history and clinical examination. Full blood count, biochemical tests and viral screen including hepatitis B surface antigen and hepatitis C virus antibody, in addition to transthoracic Doppler echocardiography for tricuspid regurgitation jet velocity (TRV). The enrolled patients had a mean (SD) age of 17.6 (5.5) years, and included 52 males and 48 females. Pulmonary hypertension as defined by TRV> 2.8 m/s coupled with both exertional dyspnea and an absence of left sided heart failure, was identified in nine patients (9%). The latter subgroup of patients had significantly higher reticulocyte counts, S. LDH, S. ferritin, and hepatitis C sero-positivity compared to those without this complication by univariate analysis. While by multivariate logistic regression only reticulocytes and hepatitis C sero-positivity remained significant. Furthermore, TRV as a continuous variable was positively correlated with reticulocytes, S. bilirubin and LDH (p<0.001, p = 0.002 and p<0.001 respectively), but not with age or S. ferritin (p = 0.77, and p = 0.93 respectively). In conclusion, pulmonary hypertension is not uncommon in Iraqi patients with thalassemia major, and it appears to be linked to chronic hemolysis rather than iron overload.

Prevalence and risk factors of high echocardiographic probability of pulmonary hypertension in myeloproliferative neoplasms patients

Pulmonary hypertension (PH) is emerging as a complication of myeloproliferative neoplasms (MPNs). This was a prospective study conducted at Chiang Mai University Hospital. The primary objective was to determine the prevalence of high echocardiographic probability of PH in MPNs patients. The secondary objectives were to determine risk factors of PH and the correlation between risk factors and peak tricuspid regurgitation velocity (TRV_max). All MPNs patients aged over 18 years, including polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofibrosis (PMF), were enrolled. All eligible patients underwent echocardiography for evaluation of the probability of PH in line with the 2015 European Society of Cardiology (ESC) and the European Respiratory Society (ERS) Guidelines. Sixty-six patients with a median age of 59 years were enrolled. There were 35 PV, 25 ET, and 6 PMF patients included. The prevalence of high echocardiographic probability of PH was 4.55% (2 ET and 1 PMF). Risk factors associated with high echocardiographic probability of PHT were not analyzed. There were three risk factors associated with increased TRV_max, specifically lower hemoglobin, older age, and the presence of JAK2V617F mutation. The prevalence of high echocardiographic probability of PH in MPNs patients was 4.55%.

A 34-Year-Old Man With Bilateral Paraspinal Masses and Shortness of Breath

CASE PRESENTATION

A 34-year-old man with history of β-thalassemia major and splenectomy presented with a 1-month history of progressively worsening dyspnea, orthopnea, localized chest discomfort, and lower extremity edema. He denied fevers, chills, nasal congestion, and night sweats. He denied tobacco, alcohol, and illicit substance abuse. Family history was remarkable for lung cancer in his mother.

Hemoglobin-bound platelets correlate with the increased platelet activity in hemoglobin E/β-thalassemia

INTRODUCTION

An increase in platelet activity is a contributing factor to vascular complications in hemoglobin E/β-thalassemia (HbE/β-thal). Plasma-free hemoglobin (Hb) increases in HbE/β-thal patients and correlates with platelet activation, but the levels of Hb-bound platelets have never been reported. In this study, we aimed to investigate the levels of Hb-bound platelets and its association with platelet activity in HbE/β-thal patients.

METHODS

Hb-bound platelets were measured by flow cytometry in 22 healthy subjects and 26 HbE/β-thal patients (16 nonsplenectomized and 10 splenectomized HbE/β-thal patients). Plasma Hb was measured by the chemiluminescence method based on the consumption of nitric oxide (NO) by Hb. Expression of P-selectin and activated glycoprotein (aGP) IIb/IIIa on platelets was measured by flow cytometry as a marker of platelet activity.

RESULTS

Both nonsplenectomized and splenectomized HbE/β-thal patients had higher levels of Hb-bound platelets and plasma Hb than healthy subjects. In vitro incubation of dialyzed Hb from patients with platelets of healthy subjects caused an increase in Hb-bound platelets, which was partially inhibited by anti-GPIbα antibody. Plasma Hb positively correlated with Hb-bound platelets. Platelet P-selectin expression at baseline and in response to adenosine diphosphate (ADP, 1 µM) stimulation was higher in nonsplenectomized and splenectomized HbE/β-thal patients than healthy subjects. The ADP-induced aGPIIb/IIIa expression on platelets was also higher in HbE/β-thal patients than healthy subjects. Hb-bound platelets correlated with baseline P-selectin expression and ADP-induced P-selectin expression.

CONCLUSION

HbE/β-thal patients have increased Hb-bound platelets, which is associated with increased baseline platelet activation and reactivity.

Pulmonary hypertension: From an orphan disease to a global epidemic

[No abstract. Showing first paragraph of article]Pulmonary hypertension is a progressive disease characterized by an elevation of pulmonary artery pressure and pulmonary vascular resistance, leading to right ventricular failure and death. It remains a challenging chronic progressive disease, but the current interest and advent of medical therapy in the last 20 years has significantly changed the perception of medical community in this disease. Pulmonary hypertension is not a specific disease; the majority of cases present with other diseases and various pathological processes that affect the pulmonary vasculature, and consequently increase pulmonary pressure and vascular resistance.

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.

Intracellular iron deficiency in pulmonary arterial smooth muscle cells induces pulmonary arterial hypertension in mice

Pulmonary arterial hypertension (PAH) is a disease in which lung blood pressure is raised chronically, causing right heart failure. It has been shown that iron deficiency also raises lung blood pressure. However, we don’t know the mechanisms because we don’t understand precisely how cells of the lung blood vessels are affected by iron levels. The smooth muscle cells of the lung blood vessels are important for controlling lung blood pressure. Our study shows that iron deficiency specifically within these cells is sufficient to cause PAH, even against a background of normal iron levels in other tissues.

Iron deficiency augments hypoxic pulmonary arterial pressure in healthy individuals and exacerbates pulmonary arterial hypertension (PAH) in patients, even without anemia. Conversely, iron supplementation has been shown to be beneficial in both settings. The mechanisms underlying the effects of iron availability are not known, due to lack of understanding of how cells of the pulmonary vasculature respond to changes in iron levels. The iron export protein ferroportin (FPN) and its antagonist peptide hepcidin control systemic iron levels by regulating release from the gut and spleen, the sites of absorption and recycling, respectively. We found FPN to be present in pulmonary arterial smooth muscle cells (PASMCs) and regulated by hepcidin cell autonomously. To interrogate the importance of this regulation, we generated mice with smooth muscle-specific knock in of the hepcidin-resistant isoform fpn C326Y. While retaining normal systemic iron levels, this model developed PAH and right heart failure as a consequence of intracellular iron deficiency and increased expression of the vasoconstrictor endothelin-1 (ET-1) within PASMCs. PAH was prevented and reversed by i.v. iron and by the ET receptor antagonist BQ-123. The regulation of ET-1 by iron was also demonstrated in healthy humans exposed to hypoxia and in PASMCs from PAH patients with mutations in bone morphogenetic protein receptor type II. Such mutations were further associated with dysregulation of the HAMP/FPN axis in PASMCs. This study presents evidence that intracellular iron deficiency specifically within PASMCs alters pulmonary vascular function. It offers a mechanistic underpinning for the known effects of iron availability in humans.

Vascular and hemostatic alterations associated with pulmonary hypertension in β-thalassemia hemoglobin E patients receiving regular transfusion and iron chelation

INTRODUCTION

Pulmonary hypertension (PH) is the commonest cardiac complication in β-thalassemia intermedia, including β-thalassemia/hemoglobin E (β-thal/HbE), and is strongly associated with splenectomy. We aimed to define the prevalence and comprehensively explore mechanisms of PH in β-thal/HbE patients receiving regular transfusion and iron chelation, which were reported to alleviate PH.

MATERIALS AND METHODS

β-Thal/HbE patients receiving regular transfusion and iron chelation over one year were enrolled. Patients at risk for PH were defined by tricuspid-regurgitant-jet-velocity (TRV) ≥ 2.5 m/s. Laboratory and echocardiographic variables were compared with healthy controls.

RESULTS

There were 68 β-thal/HbE, including 31 (45.6%) splenectomized patients, and 38 controls included for analysis. PH was detected in 29 β-thal/HbE (42.6%). β-Thal/HbE with PH had a significant reduction in nitric oxide metabolites (NOx) but elevations in thrombin-antithrombin (TAT) complex, soluble thrombomodulin (sTM), endothelin-1 (ET-1) and flow-mediated dilation (FMD) values compared to those without PH (all, p < 0.05). TRV was significantly correlated with NOx, TAT, sTM, ET-1 and FMD values (r = -0.514, r = 0.281, r = 0.313, r = 0.245 and r = -0.474; all p < 0.05). Erythropoietic activity, serum ferritin, circulating total tissue factor (TF) antigen, microparticle-associated TF activity, microparticle's procoagulant activity and soluble p-selectin levels were not different between PH and non-PH subgroups. Notably, there were no significant associations between splenectomy and PH.

CONCLUSIONS

PH remains prevalent in β-thal/HbE patients receiving long-term transfusion and iron chelation. PH is not associated with splenectomy status but correlated with NO depletion, TF-independent hypercoagulability and endothelial perturbation.

Decreased nitrite reductase activity of deoxyhemoglobin correlates with platelet activation in hemoglobin E/ß-thalassemia subjects

Nitric oxide (NO) can be generated from nitrite by reductase activity of deoxygenated hemoglobin (deoxyHb) apparently to facilitate tissue perfusion under hypoxic condition. Although hemoglobin E (HbE) solutions have been shown to exhibit decreased rate of nitrite reduction to NO, this observation has never been reported in erythrocytes from subjects with hemoglobin E/ß-thalassemia (HbE/ß-thal). In this study, we investigated the nitrite reductase activity of deoxyHb dialysates from 58 non-splenectomized and 23 splenectomized HbE/ß-thal subjects compared to 47 age- and sex-matched normal subjects, and examined its correlation with platelet activity. Iron-nitrosyl-hemoglobin (HbNO) was measured by tri-iodide reductive chemiluminescence as a marker of NO generation. HbNO produced from the reaction of nitrite with deoxyHb dialysate from both non-splenectomized and splenectomized HbE/ß-thal subjects was lower than that of normal (AA) hemoglobin subjects. P-selectin expression, a marker of platelet activation, at baseline and in reactivity to stimulation by adenosine diphosphate (ADP), were higher in HbE/ß-thal subjects than normal subjects. HbNO formation from the reactions of nitrite and deoxyHb inversely correlated with baseline platelet P-selectin expression, HbE levels, and tricuspid regurgitant velocity (TRV). Nitrite plus deoxygenated erythrocytes from HbE/ß-thal subjects had a lower ability to inhibit ADP-induced P-selectin expression on platelets than erythrocytes from normal subjects. We conclude that deoxyHb in erythrocytes from HbE/ß-thal subjects has a decreased ability to reduce nitrite to NO, which is correlated with increased platelet activity in these individuals.

Echocardiographic evaluation of prevalence of pulmonary hypertension in β-thalassemia major: A cross sectional study

INTRODUCTION

Pulmonary hypertension is a common complication associated with thalassemia syndromes and it may play an important role in the pathogenesis of right ventricle failure. The true prevalence of pulmonary hypertension in patients with thalassemia major remains unclear and has been reported to be between 2 and 79%.

MATERIALS AND METHODS

In total, 70 patients with thalassemia major were initially examined. Patients with valvular left heart disease, congenital heart diseases such as atrial septal defect (ASD) and ventricular septal defect (VSD), left heart failure, and chronic embolism were excluded. All patients with thalassemia major underwent echocardiography. Based on tricuspid regurgitation velocity (TRV), the patients were divided into the following three groups: low, medium, and high risk of pulmonary hypertension.

RESULTS

The mean age of the subjects was 24 y; 60.6% of the subjects were males and 39.4% of the subjects were females. Overall, three (4.5%) subjects were considered at a high risk of pulmonary hypertension. The mean hemoglobin level in the patients with a high probability of pulmonary hypertension was 8.2 g/dL and that in the patients with a low or medium probability of pulmonary hypertension was 9.1 g/dL. No significant difference was observed between the groups (p = .059).

CONCLUSION

This study showed that, based on new echocardiography criteria, the prevalence of pulmonary hypertension secondary to β-thalassemia was 4.5% and there was no correlation between TRV and the number of received blood units or disease duration.

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.

Deferiprone increases endothelial nitric oxide synthase phosphorylation and nitric oxide production

Iron chelation can improve endothelial function. However, effect on endothelial function of deferiprone has not been reported. We hypothesized deferiprone could promote nitric oxide (NO) production in endothelial cells. We studied effects of deferiprone on blood nitrite and blood pressure after single oral dose (25 mg/kg) in healthy subjects and hemoglobin E/β-thalassemia patients. Further, effects of deferiprone on NO production and endothelial NO synthase (eNOS) phosphorylation in primary human pulmonary artery endothelial cells (HPAEC) were investigated in vitro. Blood nitrite levels were higher in patients with deferiprone therapy than those without deferiprone (P = 0.023, n = 16 each). Deferiprone increased nitrite in plasma and whole blood of healthy subjects (P = 0.002 and 0.044) and thalassemia patients (P = 0.003 and 0.046) at time 180 min (n = 20 each). Asymptomatic reduction in diastolic blood pressure (P = 0.005) and increase in heart rate (P = 0.009) were observed in healthy subjects, but not in thalassemia patients. In HPAEC, deferiprone increased cellular nitrite and phospho-eNOS (Ser1177) (P = 0.012 and 0.035, n = 6) without alteration in total eNOS protein and mRNA. We conclude that deferiprone can induce NO production by enhancing eNOS phosphorylation in endothelial cells.

Hematological disorders and pulmonary hypertension

Pulmonary hypertension (PH), a serious disorder with a high morbidity and mortality rate, is known to occur in a number of unrelated systemic diseases. Several hematological disorders such as sickle cell disease, thalassemia and myeloproliferative diseases develop PH which worsens the prognosis. Associated oxidant injury and vascular inflammation cause endothelial damage and dysfunction. Pulmonary vascular endothelial damage/dysfunction is an early event in PH resulting in the loss of vascular reactivity, activation of proliferative and antiapoptotic pathways leading to vascular remodeling, elevated pulmonary artery pressure, right ventricular hypertrophy and premature death. Hemolysis observed in hematological disorders leads to free hemoglobin which rapidly scavenges nitric oxide (NO), limiting its bioavailability, and leading to endothelial dysfunction. In addition, hemolysis releases arginase into the circulation which converts L-arginine to ornithine, thus bypassing NO production. Furthermore, treatments for hematological disorders such as immunosuppressive therapy, splenectomy, bone marrow transplantation, and radiation have been shown to contribute to the development of PH. Recent studies have shown deregulated iron homeostasis in patients with cardiopulmonary diseases including pulmonary arterial hypertension (PAH). Several studies have reported low iron levels in patients with idiopathic PAH, and iron deficiency is an important risk factor. This article reviews PH associated with hematological disorders and its mechanism; and iron homeostasis and its relevance to PH.