Splenectomy changes the pattern of cytokine production in beta-thalassemic patients

Pathophysiology and Treatment of Chronic Thromboembolic Pulmonary Hypertension

Chronic thromboembolic pulmonary hypertension (CTEPH) is a condition in which an organic thrombus remains in the pulmonary artery (PA) even after receiving anticoagulation therapy for more than 3 months and is complicated by pulmonary hypertension (PH), leading to right-sided heart failure and death. CTEPH is a progressive pulmonary vascular disease with a poor prognosis if left untreated. The standard treatment for CTEPH is pulmonary endarterectomy (PEA), which is usually performed only in specialized centers. In recent years, balloon pulmonary angioplasty (BPA) and drug therapy for CTEPH have also shown good results. This review discusses the complex pathogenesis of CTEPH and presents the standard of care, PEA, as well as a new device called BPA, which is showing remarkable progress in efficacy and safety. Additionally, several drugs are now demonstrating established evidence of efficacy in treating CTEPH.

Hemorheological profiles and chronic inflammation markers in transfusion-dependent and non-transfusion- dependent thalassemia

The rheological properties of blood play an important role in regulating blood flow in micro and macro circulation. In thalassemia syndromes red blood cells exhibit altered hemodynamic properties that facilitate microcirculatory diseases: increased aggregation and reduced deformability, as well as a marked increase in adherence to the vascular endothelial cells. A personalized approach to treating thalassemia patients (transfusions, iron chelation, and splenectomy), has increased patients' life expectancy, however they generally present many complications and several studies have demonstrated the presence of high incidence of thromboembolic events. In this study the hemorheological profiles of thalassemia patients have been characterized to point out new indices of vascular impairment in thalassemia. Plasma viscosity, blood viscosities at low and high shear rates (η1 and η200, respectively), erythrocyte aggregation index (η1/η200), and the erythrocyte viscoelastic profile (elastic modulus G', and viscous modulus G") have been studied in transfusion-dependent and non-transfusion-dependent thalassemia patients. Moreover, the levels of inflammation biomarkers in thalassemia have been evaluated to investigate a relationship between the biomarkers, the disease severity and the rheological parameters. The biomarkers studied are the main components of the immune and endothelial systems or are related to vascular inflammation: cytokines (IL-2, IL-6, IL-10, IL-17A, TNF-alpha), chemokines (IL-8, MIP-1alpha), adipocytokines (leptin and adiponectin), growth factors (VEGF, angiopoietin-1), adhesion molecules (ICAM-1, VCAM-1, E-selectin, L-selectin), and a monocyte/macrophage activation marker (CD163). This study shows that transfusion-dependent thalassemia patients, both major and intermedia, have blood viscosities comparable to those of healthy subjects. Non-transfusion-dependent thalassemia intermedia patients show high blood viscosities at low shear rates (η1), corresponding to the flow conditions of the microcirculation, an increase in erythrocyte aggregation, and high values of the elastic G' and viscous G" modules that reflect a reduced erythrocyte deformability and an increase in blood viscosity. Levels of cytokines, chemokines and adhesion molecules are different in transfusion- and non-transfusion dependent patients and positive correlations between η1 or η1/η200 and the cytokines IL-6 and IL-10 have been observed. The evaluation of the hemorheological profiles in thalassemia can provide new indicators of vascular impairment and disease severity in thalassemia in order to prevent the onset of thromboembolic events.

Implications of SARSr-CoV 2 infection in thalassemias: Do patients fall into the "high clinical risk" category?

We're all flying blind regarding coronavirus, but it's fair to think if thalassemic patients are particularly vulnerable to SARS-COV-2  infection or are at potential higher risk of complications from COVID-19 than normal population, specially when they become older. The frustrating thing is that, right now,  this virus is still new. It only came to the attention of the World Health Organization at the end of December. Very few cases in thalassemia have so far been reported; is this due to lack of testing or a true lack of infection/susceptibility? However, we believe that more data should be collected to better characterise the impact of SARS-CoV-2 infection in patients with thalassemias. Therefore, a multicenter registry and the collection of comprehensive data from both positive COVID-19 thalassemia major and non-transfusion dependent thalassemia are necessary to clarify debated issues. In the meantime an early and vigilant monitoring along with high quality supportive care are needed in thalassemic patients at high risk for SARS-CoV-2 infection.

Evaluation of regulatory T cells frequency and FoxP3/GDF-15 gene expression in β-thalassemia major patients with and without alloantibody; correlation with serum ferritin and folate levels

β-thalassemia major is one of the most common hematologic disorders in the world. It causes severe anemia and patients require regular blood transfusions, which causes different complications such as iron overload and alloimmunization. Regulatory T cells (Tregs) have an important role in regulation of immune responses. FoxP3 is the major marker of Tregs and its expression can be influenced by different factors. GDF-15 is another gene that plays a role in iron homeostasis and regulation of immune system in different diseases. The aim of this study was to assess the frequency of Tregs and FoxP3/GDF-15 gene expression in β-thalassemia major patients with and without alloantibody as well as its correlation with different factors such as serum ferritin and folate levels. This study was conducted on 68 β-thalassemia major patients with and without alloantibodies in comparison with 20 healthy individuals with matched age and sex as control group. Enzyme-linked immunosorbent assay (ELISA), flow cytometry, and real-time PCR were performed in order to evaluate serum ferritin and folate levels, frequency of Tregs, and the expression of FoxP3 and GDF-15 genes, respectively. The percentage and absolute count of Tregs were increased in patients compared with controls (P = 0.0003), but there was no difference between responders and non-responders (P > 0.05). The Tregs count correlated positively with serum ferritin. No correlation was observed between target genes and serum ferritin and folate, but there was a positive significant correlation between the expression of FoxP3 and GDF-15 genes, which shows the immunosuppressive role of GDF-15.

Current understanding of the pathophysiology of chronic thromboembolic pulmonary hypertension

Chronic thromboembolic pulmonary hypertension (CTEPH) is a unique form of pulmonary hypertension arising from fibrotic obliteration of major pulmonary arteries. Pro-thrombotic states, large clot burden and impaired dissolution are believed to contribute to the occurrence and progression of thrombosis after an acute pulmonary embolic event. Recent data utilizing several models have facilitated the understanding of clot resolution. This review summarizes current knowledge on pathophysiological mechanisms of major vessel occlusion in CTEPH.

Protein-based therapeutic for anemia caused by dyserythropoiesis

INTRODUCTION

Major advances have been recently made in understanding the molecular determinants of dyserythropoiesis, particularly due to recent works in β-thalassemia. The purpose of this review is devoted to underline the role of some proteins recently evidenced in the field, that may be new alternative therapeutic targets in the near future to alleviate different types of anemia. Areas covered: This review covers the contemporary aspects of some proteins involved in various types of dyserythropoiesis, including the transcriptional factor GATA-1 and its protective chaperone HSP70, but also cytokines of the transforming growth factor beta (TFG-β) family, TGF-β1 and GDF-11, and hormones as erythroferrone. It will be not exhaustive, but based on major recent published works from the literature in the past three years. Expert commentary: Sotatercept and lustatercept, two activin receptor II ligand traps that block GDF-11, are candidate drugs providing therapeutic hope in different types of ineffective erythropoiesis, including myelodysplastic syndromes (MDS) and β-thalassemia. Furthermore, a new concept emerges to consider erythroid lineage in the bone marrow as an endocrine gland.

Increased IL-17 and TGF-β serum levels in peripheral blood of patients with β-thalassemia major: implication for continual transfusions role in T helper17-mediated proinflammatory responses

BACKGROUND/AIM

Recent studies have shown that IL-17-producing CD4+ T helper (Th17) cells play an important role in proinflammatory processes. In this report we analyzed IL-17, IL-21, and TGF-β serum levels in the peripheral blood of Iranian beta-thalassemia major patients that clinically exhibited splenectomy and iron overload.

MATERIALS AND METHODS

Blood samples were collected from 43 beta-thalassemia patients and 43 healthy individuals with no history of malignancies or autoimmune disorders. Then serum levels of IL-17, IL-21, and TGF-β were measured by enzyme linked immunosorbent assay (ELISA).

RESULTS

The levels of IL-17 (P = 0.005) and TGF-β (P < 0.001) were significantly higher in the thalassemia patients compared to the healthy control. No significant differences in the level of serum IL-21 was observed between the patients and controls. There were no significant differences in serum levels of IL-17, IL-21, and TGF-β between patients with high or low serum levels of ferritin.

CONCLUSION

Multiple blood transfusions cause constant immune stimulation, as a result of repeated exposure to new alloantigens. This might have significant effects on the stimulation of cytokine producing cells in those patients and cytokine profile can be used as a related marker for assessing disease severity and consequently therapeutic intervention.

Review: Beta-thalassemia and molecular chaperones

Thalassemia is known as a diverse single gene disorder, which is prevalent worldwide. The molecular chaperones are set of proteins that help in two important processes while protein synthesis and degradation include folding or unfolding and assembly or disassembly, thereby helping in cell homeostasis. This review recaps current knowledge regarding the role of molecular chaperones in thalassemia, with a focus on beta thalassemia.

Assessment of serum zinc levels of patients with thalassemia compared to their siblings

Zinc (Zn) is essential for appropriate growth and proper immune function, both of which may be impaired in thalassemia children. Factors that can affect serum Zn levels in these patients may be related to their disease or treatment or nutritional causes. We assessed the serum Zn levels of children with thalassemia paired with a sibling. Zn levels were obtained from 30 children in Islamabad, Pakistan. Serum Zn levels and anthropometric data measures were compared among siblings. Thalassemia patients' median age was 4.5 years (range 1–10.6 years) and siblings was 7.8 years (range 1.1–17 years). The median serum Zn levels for both groups were within normal range: 100 μg/dL (10 μg/dL–297 μg/dL) for patients and 92 μg/dL (13 μg/dL–212 μg/dL) for siblings. There was no significant difference between the two groups. Patients' serum Zn values correlated positively with their corresponding siblings (r = 0.635, P < 0.001). There were no correlations between patients' Zn levels, height for age Z-scores, serum ferritin levels, chelation, or blood counts (including both total leukocyte and absolute lymphocyte counts). Patients' serum Zn values correlated with their siblings' values. In this study, patients with thalassemia do not seem to have disease-related Zn deficiency.

Splenectomy is modifying the vascular remodeling of thrombosis

Background

Splenectomy is a clinical risk factor for complicated thrombosis. We hypothesized that the loss of the mechanical filtering function of the spleen may enrich for thrombogenic phospholipids in the circulation, thereby affecting the vascular remodeling of thrombosis.

Methods and Results

We investigated the effects of splenectomy both in chronic thromboembolic pulmonary hypertension (CTEPH), a human model disease for thrombus nonresolution, and in a mouse model of stagnant flow venous thrombosis mimicking deep vein thrombosis. Surgically excised thrombi from rare cases of CTEPH patients who had undergone previous splenectomy were enriched for anionic phospholipids like phosphatidylserine. Similar to human thrombi, phosphatidylserine accumulated in thrombi after splenectomy in the mouse model. A postsplenectomy state was associated with larger and more persistent thrombi. Higher counts of procoagulant platelet microparticles and increased leukocyte–platelet aggregates were observed in mice after splenectomy. Histological inspection revealed a decreased number of thrombus vessels. Phosphatidylserine‐enriched phospholipids specifically inhibited endothelial proliferation and sprouting.

Conclusions

After splenectomy, an increase in circulating microparticles and negatively charged phospholipids is enhanced by experimental thrombus induction. The initial increase in thrombus volume after splenectomy is due to platelet activation, and the subsequent delay of thrombus resolution is due to inhibition of thrombus angiogenesis. The data illustrate a potential mechanism of disease in CTEPH.

Effects of micro environmental factors on natural killer activity (NK) of beta thalassemia major patients

The physiological mechanisms of decreased NK activity of β-Thalassemia major (BTM) patients are unknown. To assess in vitro effects of mononuclear cells and their cytokine secretion on NK activity, we compared activator receptor levels and cytotoxic activity of purified NK cells and NK cells in mononuclear cells (MNC) pools. We collected cell supernatant from unincubated and incubated MNC with K562 cells and measured their secreted cytokines levels. CD16 was lower on the surface of NK cells in MNC pools from BTM patients compared to healthy volunteers. This inhibition does not appear when NK cells were purified. NKp30 levels in NK cells decreased both as purified cells and as part of a pool of MNC in BTM patients. After incubation of MNC pools with K562 target cells, we found that supernatant levels of IL10, TGFβ1 and IL15 cytokines were also significantly higher in BTM patients compared to healthy volunteers.

Ineffective erythropoiesis in β -thalassemia

In humans, β-thalassemia dyserythropoiesis is characterized by expansion of early erythroid precursors and erythroid progenitors and then ineffective erythropoiesis. This ineffective erythropoiesis is defined as a suboptimal production of mature erythrocytes originating from a proliferating pool of immature erythroblasts. It is characterized by (1) accelerated erythroid differentiation, (2) maturation blockade at the polychromatophilic stage, and (3) death of erythroid precursors. Despite extensive knowledge of molecular defects causing β-thalassemia, less is known about the mechanisms responsible for ineffective erythropoiesis. In this paper, we will focus on the underlying mechanisms leading to premature death of thalassemic erythroid precursors in the bone marrow.

Comparative effectiveness of different types of splenectomy for children with congenital hemolytic anemias

OBJECTIVE

To compare the effectiveness of different types of splenectomy in children with congenital hemolytic anemias.

STUDY DESIGN

We constructed key questions that addressed outcomes relevant to clinicians and families on effects of partial or total splenectomy, including hematologic effect, splenic function, and the risk of adverse events. We identified from Pubmed and Embase 703 studies that evaluated different types of splenectomy and accepted 93 studies that satisfied entry criteria. We graded the quality of each report and summarized the overall strength of research evidence for each key question.

RESULTS

We did not identify any randomized clinical trials. All types of splenectomy have favorable clinical outcomes in most diseases. We did not identify any hematologic advantage of laparoscopy compared with laparotomy. Adverse events are uncommon in most studies and are minimized with use of laparoscopy.

CONCLUSIONS

There is a need for randomized clinical trials and improved data collection of different types of splenectomy in congenital hemolytic anemias. Outcomes studied should address the concerns of families and clinicians to assess the risks and benefits of various treatments.

Immune regulation in chronically transfused allo-antibody responder and nonresponder patients with sickle cell disease and β-thalassemia major

Red blood cell alloimmunization is a major complication of transfusion therapy. Host immune markers that can predict antibody responders remain poorly described. As regulatory T cells (Tregs) play a role in alloimmunization in mouse models, we analyzed the Treg compartment of a cohort of chronically transfused patients with sickle cell disease (SCD, n = 22) and β-thalassemia major (n = 8) with and without alloantibodies. We found reduced Treg activity in alloantibody responders compared with nonresponders as seen in mice. Higher circulating anti-inflammatory IL-10 levels and lower IFN-γ levels were detected in non-alloimmunized SCD patients. Stimulated sorted CD4+ cells from half of the alloimmunized patients had increased frequency of IL-4 expression compared with nonresponders, indicating a skewed T helper (Th) 2 humoral immune response in a subgroup of antibody responders. All patients had increased Th17 responses, suggesting an underlying inflammatory state. Although small, our study indicates an altered immunoregulatory state in alloantibody responders which may help future identification of potential molecular risk factors for alloimmunization.

Bone loss caused by iron overload in a murine model: importance of oxidative stress

Osteoporosis is a frequent problem in disorders characterized by iron overload, such as the thalassemias and hereditary hemochromatosis. The exact role of iron in the development of osteoporosis in these disorders is not established. To define the effect of iron excess in bone, we generated an iron-overloaded mouse by injecting iron dextran at 2 doses into C57/BL6 mice for 2 months. Compared with the placebo group, iron-overloaded mice exhibited dose-dependent increased tissue iron content, changes in bone composition, and trabecular and cortical thinning of bone accompanied by increased bone resorption. Iron-overloaded mice had increased reactive oxygen species and elevated serum tumor necrosis factor-α and interleukin-6 concentrations that correlated with severity of iron overload. Treatment of iron-overloaded mice with the antioxidant N-acetyl-L-cysteine prevented the development of trabecular but not cortical bone abnormalities. This is the first study to demonstrate that iron overload in mice results in increased bone resorption and oxidative stress, leading to changes in bone microarchitecture and material properties and thus bone loss.