Biology and Therapeutic Properties of Mesenchymal Stem Cells in Leukemia

This comprehensive review delves into the multifaceted roles of mesenchymal stem cells (MSCs) in leukemia, focusing on their interactions within the bone marrow microenvironment and their impact on leukemia pathogenesis, progression, and treatment resistance. MSCs, characterized by their ability to differentiate into various cell types and modulate the immune system, are integral to the BM niche, influencing hematopoietic stem cell maintenance and functionality. This review extensively explores the intricate relationship between MSCs and leukemic cells in acute myeloid leukemia, acute lymphoblastic leukemia, chronic myeloid leukemia, and chronic lymphocytic leukemia. This review also addresses the potential clinical applications of MSCs in leukemia treatment. MSCs' role in hematopoietic stem cell transplantation, their antitumor effects, and strategies to disrupt chemo-resistance are discussed. Despite their therapeutic potential, the dual nature of MSCs in promoting and inhibiting tumor growth poses significant challenges. Further research is needed to understand MSCs' biological mechanisms in hematologic malignancies and develop targeted therapeutic strategies. This in-depth exploration of MSCs in leukemia provides crucial insights for advancing treatment modalities and improving patient outcomes in hematologic malignancies.

Efficacy, safety and cost of emicizumab prophylaxis in haemophilia A patients with inhibitors: A nationwide observational study in Taiwan

INTRODUCTION

Emicizumab mimicking the cofactor function of activated factor VIII (FVIII) restores haemostasis.

METHODS

This nationwide observational study aimed to retrospectively investigate efficacy, safety, and cost in 1 year before and up to 3 years after emicizumab prophylaxis for haemophilia A (HA) patients with FVIII inhibitors.

RESULTS AND DISCUSSION

A total of 39 severe HA patients with a median age of 23.0 years were enrolled. The median historical peak FVIII inhibitor titre was 174.2 BU/mL with an interquartile range of 56.5-578.8 BU/mL. The median annualized bleeding rate reduced from 24 to 0 events in the first year after emicizumab prophylaxis (p < .01) and sustained in the second and third years. The median annualized joint bleeding rate reduced to 0 and maintained up to 3 years (p < .01). Twenty-seven patients (69.2%) had target joints before emicizumab prophylaxis and only seven patients (17.9%) of them had target joints after prophylaxis. Medical costs, including cost of haemostatic therapy, frequency of outpatient department visits, emergency room visits and hospital admission, were significantly reduced after emicizumab prophylaxis (p < .01). FVIII inhibitor titre decreased after emicizumab prophylaxis. Overall, three (7.7%) patients experienced 202 grade 1 drug-related adverse events after emicizumab prophylaxis. No serious adverse events were reported during emicizumab prophylaxis period. The adherence to emicizumab prophylaxis was 100% up to 3 years.

CONCLUSIONS

HA patients with FVIII inhibitors treated with emicizumab prophylaxis resulted in a significant reduction in treated bleeds and associated costs. No new safety events were observed.

Antithymocyte Globulin Plus Post-Transplant Cyclophosphamide Combination as an Effective Strategy for Graft-versus-Host Disease Prevention in Haploidentical Peripheral Blood Stem Cell Transplantation for Children with High-Risk Malignancies

Haploidentical hematopoietic stem cell transplantation using post-transplant cyclophosphamide (PTCy) for graft-versus-host disease (GVHD) prophylaxis has emerged as a valid alternative transplant strategy for patients lacking a suitable HLA-matched related donor. The high risk of severe GVHD remains the major clinical challenge in this setting. The addition of antithymocyte globulin (ATG) in PTCy-based regimens for GVHD reduction in haploidentical hematopoietic stem cell transplantation is rational and was reported in adult series. However, its feasibility is unknown in pediatric patients. Here, we firstly describe our experience of 15 consecutive children with high-risk malignancies receiving haploidentical peripheral blood stem cell transplantation using ATG plus PTCy for GVHD prophylaxis. Only three patients developed grade 1-2 acute GVHD, limited to skin. No grade 3-4 acute GVHD and chronic GVHD were observed. Viral reactivations were frequently seen but manageable. Six patients relapsed, as the main cause of death in our series. None died from events related to GVHD. Our data suggest that ATG plus PTCy is an effective strategy for GVHD prevention in haploidentical peripheral blood stem cell transplantation and is feasible in children with high-risk malignancies.

Surgical treatment confers prognostic significance in pediatric malignant mediastinal germ cell tumors

BACKGROUND

Primary malignant mediastinal germ cell tumors (GCTs) are rare pediatric tumors that have a poorer prognosis compared to GCTs occurring elsewhere in the body. The current study aimed to assess the prognostic factors and treatment outcomes of children with primary malignant mediastinal GCT in Taiwan.

METHODS

The authors retrospectively reviewed children 0-18 years old who were newly diagnosed with primary malignant mediastinal GCT between January 1, 2005 and December 31, 2019 and were registered in the Taiwan Pediatric Oncology Group patient registry. The impact of presenting characteristics, including sex, age, tumor stage, histology subtype, surgical treatment, and chemotherapy regimens of the patients were analyzed.

RESULTS

This study enrolled 52 children with malignant mediastinal GCT who had a median age of 16.0 (range, 6.0-17.9) years at diagnosis. The most common histological subtypes were mixed GCTs (n = 20) and yolk sac tumors (n = 15). Advanced disease stage and choriocarcinoma histology subtype were associated inferior outcomes. Children who received surgical treatment exhibited better outcomes compared to those who did not (5-year overall survival, 78% vs. 7%, p < .001). After comparing patients who received first-line cisplatin- and carboplatin-based chemotherapy, no difference in treatment outcomes was observed. Multivariate analysis showed that surgical management was the only independent predictor for superior OS.

CONCLUSIONS

Surgical treatment is recommended for mediastinal GCT. Cisplatin-based chemotherapy was not superior to carboplatin-based chemotherapy as first-line treatment and may be avoided due to toxicity concerns.

Clinical Consideration for Mesenchymal Stem Cells in Treatment of COVID-19

COVID-19, which has strongly affected the 21st century, is caused by severe acute respiratory syndrome (SARS)-CoV-2. The emergence of viral variants has rendered even vaccinated people prone to infection; thus, completely eradicating COVID-19 may be impossible. COVID-19 causes hyperinflammation, leading to organ damage and even death. SARS-CoV-2 infects not only the lungs, causing acute respiratory distress syndrome, but also the extrapulmonary organs. Not all patients with COVID-19 respond adequately to treatments with antiviral and anti-inflammatory drugs. Therefore, new treatments are urgently needed. Mesenchymal stem cells (MSCs) exhibit immunomodulatory activity and are used to safely and effectively treat various immune disorders. Evidence has indicated the efficacy of MSCs against COVID-19. However, the safety and efficacy of MSCs must be probed further. For this reason, we explored key clinical challenges associated with MSC therapy for COVID-19, such as sources, administration routes, cell dosage, treatment timepoint, and virus reactivation. We identified several challenges that must be addressed before MSCs can be clinically applied.

Prevalence of non-Alcoholic Fatty Liver Disease and Associated Factors in Patients with Moderate or Severe Hemophilia: A Multicenter-Based Study

Introduction

Liver health is essential for persons with hemophilia (PWH) in order to maintain access to new therapies, such as gene therapy. Non-alcoholic fatty liver disease (NAFLD) is seldom reported in the hemophilia population. The study aimed to investigate the prevalence of NAFLD and associated factors in PWH.

Methods

Data of this cross-sectional study were obtained from a multicenter collaborative registry database.

Results

A total of 163 moderate or severe PWH with a complete data of liver examination were analyzed. There were 77 (47.2%) PWH diagnosed with NAFLD. The multivariate analysis showed that overweight/obesity was associated with NAFLD (OR, 4.31, P < .001). In comparison with hemophilia B patients, hemophilia A patients showed a weaker correlation with NAFLD, (OR, 0.30, P = .009). A total of 17 (25.8%) PWH with NAFLD had an elevated level of alanine transaminase (ALT). Both overweight/obesity and presence of inhibitor to clotting factor were independently associated with elevated ALT in PWH with NAFLD.

Conclusions

The study indicated that a high prevalence of NAFLD existed in the hemophilia population. Overweight/obesity was an independent factor for NAFLD and elevated ALT.

Toll-like receptor signalling associated with immunomodulation of umbilical cord-derived mesenchymal stem cells in mice with systemic lupus erythematosus

With potent immunomodulatory activities, mesenchymal stem cells (MSCs) have the potential to be a beneficial treatment option for diseases with aberrant immune responses such as systemic lupus erythematosus (SLE). However, the underlying mechanisms remain largely unknown. Here, we used NZBWF1 mice as a SLE animal model to examine immunomodulation of MSCs as well as to assess the role of Toll-like receptor signalling in this circumstance. We found that mice receiving MSCs had a significant decrease in severity of proteinuria at 20 and 22 weeks of age (p = 0.009 and p = 0.022, respectively). Serum anti-dsDNA levels were significantly lower compared with the control group (p = 0.016 and p = 0.036, respectively). C3 and C4 levels were significantly higher at 22 weeks of age (p = 0.046 and p = 0.016, respectively). Altered expression of inflammation-associated cytokine profiles in the serum was also noted in mice receiving MSCs. Down-regulation of myeloid differentiation factor 88 (MyD88)-nuclear factor-κB (NF-κB) signalling in the liver was demonstrated by quantitative polymerase chain reaction, ELISA and Western blotting. In addition to demonstrating the beneficial effects of MSC treatment in NZBWF1 mice, our study provided the first evidence for the association of MyD88-NF-κB signalling and MSC-mediated immunomodulation in this disease.

Therapeutic mechanism of combined oral chelation therapy to maximize efficacy of iron removal in transfusion-dependent thalassemia major - a pilot study

OBJECTIVES

Three iron chelators are used to treat transfusion-dependent beta-thalassemia: desferrioxamine (DFO), deferasirox (DFX), and deferiprone (DFP). Compliance is low for DFO as it cannot be administered orally. Combined administration of DFP and DFX is orally available, however, the therapeutic mechanism is unknown. This pilot study investigated the iron removal mechanisms of DFX and DFP treatment in patients with transfusion-dependent thalassemia major.

METHODS

Each patient received three treatments sequentially: (1) DFX monotherapy, (2) DFP monotherapy, and (3) DFX/DFP combination therapy with a four-day washout period between each treatment. Urine and stool specimens were collected to determine the primary outcome of iron excretion volumes.

RESULTS

The mean iron excretion was seven times higher after combination therapy with DFX and DFP. Monotherapies also increased excretions volumes, though to a significantly lesser degree. Combined administration of DFX and DFP achieves maximum iron removal in transfusion-dependent thalassemia major compared to monotherapy with either drug.

CONCLUSIONS

We suggest combination therapy in chronic severe iron overload cases, especially for patients in poor compliance with DFO/DFP combination therapy or those exhibiting poor iron removal from DFX or DFP monotherapy.

Increased apoptosis and peripheral blood mononuclear cell suppression of bone marrow mesenchymal stem cells in severe aplastic anemia

BACKGROUND

Although immune-mediated pathogenesis is considered an important aspect of severe aplastic anemia (SAA), its underlying mechanisms remain unclear. Mesenchymal stem cells (MSCs) are essential to the formation of specialized microenvironments in the bone marrow (BM), and MSC insufficiency can trigger the development of SAA.

METHODS

To find MSC alterations in the SAA BM, we compared BM MSCs from five children with SAA and five controls. Peripheral blood mononuclear cells (PBMCs) were cocultured with MSCs to evaluate the supportive effects of MSCs on hematopoiesis. Cytometric bead array immunoassay was used to determine cytokine excretion by MSCs. The immune functions of MSCs and their conditioned medium (CM) were evaluated by PBMC proliferation assays.

RESULTS

SAA MSCs were characterized by a high percentage of cells in the abnormal sub-G1 phase of the cell cycle, which suggests an increased rate of apoptosis in SAA MSCs. In comparison with control MSCs, PBMCs cocultured with SAA MSCs displayed significantly reduced PBMC proliferation (P = 0.009). Aberrant cytokine profiles were secreted by SAA MSCs, with increased concentrations of interleukin-6, interferon-γ, tumor necrosis factor-α, and interleukin-1β in the CM. PBMC proliferation assays demonstrated additional immunosuppressive effects of SAA MSCs (P = 0.016) and their CM (P = 0.013).

CONCLUSIONS

Our data revealed increased apoptosis and PBMC suppression of SAA MSCs. The alterations of MSCs may contribute to the formation of functionally abnormal microenvironments in SAA BM.

Everolimus for pediatric patients with acute graft-versus-host disease after hematopoietic stem cell transplantation: A pilot study

Acute graft-versus-host disease (aGVHD) is a significant cause of morbidity and mortality after allogeneic hematopoietic stem cell transplantation (HSCT). Due to the poor prognosis for patients not responding to first-line steroids treatment, improvements in aGVHD therapy are needed. Everolimus is a promising candidate that combines immunosuppressive properties with anti-neoplastic effects. Here, we retrospectively reviewed the efficacy of everolimus with steroids as primary treatment in 13 patients with grade II to grade IV aGVHD after HSCT. Among them, 12 (92.3%) had complete response to everolimus with steroids without additional immunosuppressive agents. The median duration of therapy was 76 days (range 20-110). Asymptomatic hypertriglyceridemia was the most common therapy complication (69.2%), but treatment interruption was not needed. Thrombotic microangiopathy was rare (7.7%), but can be quickly solved by stopping everolimus and cyclosporine treatment. Other toxicities were manageable. Two patients developed chronic GVHD (15.4%), limited in one and extensive in the other. The overall survival was 76.9% with a median follow-up of 3.4 years after HSCT (range 0.7-5.7). Accordingly, everolimus with steroids were feasible for patients with aGVHD after HSCT as primary treatment. Further large-scale studies are required.

Changes of serum aspergillus galactomannan during hematopoietic stem cell transplantation in children with prior invasive aspergillosis

Background

Invasive aspergillosis (IA) has recently increased and has a high mortality rate in immunocompromised patients. IA before hematopoietic stem cell transplantation (HSCT) is not uncommon, but how to cope with it is very tough. The serum aspergillus galactomannan antigen (GM) is a helpful marker for diagnosis of IA, and a serial follow-up of GM levels is important to evaluate the response of treatment. However, data on the changes of GM during HSCT are very limited.

Case presentation

Patient 1 was a 2-year-old female with severe aplastic anemia. A typical lung lesion in the computed tomography of the chest with elevated GM levels was noted, and probable IA was diagnosed. After a combination treatment of voriconazole and caspofungin, the GM levels decreased. Although of significant improvement, the pulmonary lesion in the chest X-ray did not disappear before HSCT. The GM levels increased when she received the conditioning regimen during HSCT. The GM levels remained high during the use of steroids for the graft-versus-host disease and declined gradually after tapering off steroids and cyclosporine. Patient 2 was a 12-year-old female with severe aplastic anemia. Voriconazole was administered after the diagnosis of a probable IA. The pulmonary lesions in the chest X-ray disappeared before HSCT. The GM levels flared up during the administration of conditioning regimen and declined after neutrophil engraftment. At present, the two patients were cured of the disease without requiring surgical resection of their pulmonary IA.

Conclusion

To our knowledge, this is the first report about the changes of GM during HSCT in patients with prior IA. With appropriate antifungal therapy and restoration of patient’s immunity, IA can be cured without surgical resection. Further studies are warranted.

Successful treatment of disseminated mixed invasive fungal infection after hematopoietic stem cell transplantation for severe aplastic anemia

Concomitant infections are frequent and usually the causes of death in patients with severe AA. HSCT can restore hematopoiesis in AA, but it is usually life threatening when patients simultaneously have an IFI. Mixed IFIs have been reported on rare occasions. The exact diagnosis of IFIs is difficult because of low fungus culture rate, difficultly obtaining tissue specimens in severely immunocompromised patients or those with bleeding tendencies. Otherwise, treatment with anti-fungal drugs alone for DMIFI was always lethal in previous reports. Surgical resection is crucial for invasive zygomycosis, but severe pancytopenia and bleeding tendency make therapy difficult. Herein, we report that with a combination of aggressive anti-fungal drugs, HSCT, and surgery, we successfully treated a 10-yr-old boy with severe AA and pulmonary zygomycosis before HSCT and disseminated mixed invasive zygomycosis and aspergillosis after HSCT.