New insights in the mobilization of hematopoietic stem cells in lymphoma and multiple myeloma patients

Cord Blood-Derived Multipotent Stem Cells Ameliorate in Vitro/in Vivo Alloreactive Responses, and This Effect Is Associated with Exosomal Microvesicles in Vitro

Human cord blood derived-multipotent stem cells (CB-SCs) have been found to have immunomodulatory capabilities that can result in inhibition of immune activation. Clinically, when used to interact with apheresed peripheral blood mononuclear cells (PBMCs) before reinfusion, they can counteract inflammation and restore immune balance in patients with autoimmune diseases, including alopecia areata and type 1 diabetes. The present study aimed to explore the potential application of CB-SCs to control donor alloreactive responses involved in allogeneic hematopoietic cell transplantation, which often results in acute graft-versus-host disease (GVHD). Phenotypically, we demonstrated that CB-SCs express CD45, CD11b, and CD9 markers on the cell surface; express Oct3/4, a transcription factor for embryonic stem cells; are negative for CD3, CD14, and CD34 expression; and have low expression of HLA-DR. In an allogeneic mixed lymphocyte culture (MLC) using human CD4 T cell enriched PBMCs and allogeneic myeloid derived dendritic cells, direct coculture with CB-SCs decreased CD4 T cell proliferation and activation, as evidenced by a marked decrease in the expression of the late activation markers CD25 and HLA-DR and a reduction of the PKH26 cell proliferation membrane lipophilic marker. Cytokine profiling of MLC supernatants revealed decreased concentrations of inflammatory proteins, including IFN-γ, IL-17, IL-13, IL-2, IL-6, and MIP1-α, along with marked increases in IL-1RA, IP-10, and MCP-1 concentrations in the presence of CB-SCs. Furthermore, transwell MLC experiments revealed that a soluble component was partially responsible for the immunomodulatory effects of CB-SCs. In this regard, exosomal microvesicles (EVs) positive for CD9, CD63, and CD81 were found in CB-SC-derived, ultrafiltered, and ultracentrifuged culture supernatants. CB-SC-EVs inhibited T cell proliferation in allogeneic MLC, suggesting a potential mode of action in allogeneic responses. Finally, CB-SCs were evaluated for their cellular therapy potential in vivo and found to ameliorate the development of GVHD responses in a xenogeneic human PBMC-induced NSG mouse model. Taken together, our results indicate that CB-SCs can directly and indirectly attenuate alloreactive CD4 T cell activation and proliferation in vitro with a potentially related EV mode of action and may have potential as a cellular therapy to control donor T cell-mediated GVHD responses in vivo.

A concise review on factors influencing the hematopoietic stem cell transplantation main outcomes

BACKGROUND AND AIMS

As a curative procedure, hematopoietic stemcell transplantation (HSCT) is an approved treatment for many malignant orbenign hematologic and non-hematologic diseases. There are different outcomes of HSCT, as well as several parameters influencing these outcomes.

METHODS

We had searched scientific sources like Web ofScience and PubMed with a combination of keywords such as HSCT, engraftment,survival, outcomes, etc. Totally, 80 articles were included.

RESULTS

Here we have reviewed the effective factors onmain outcomes of HSCT including engraftment, survival, graft versus hostdisease, and Mobilization. Also, the prediction of hematological reconstitutionand some novel suggestions leading to better outcomes are reviewed.

CONCLUSION

The study will be applicable for improvedmanagement of autologous and allogeneic HSCT process to increase the procedureefficiency.

Impact of CD44 gene single nucleotide polymorphism (rs 13347) in mobilization of autologous HSCT

MOBILIZATION: of stem cells into peripheral blood is a crucial step in the procedure of autologous stem cell transplantation. Mobilization can be affected by many variables;underlying diseases, prior treatment and age. Many genetic polymorphisms mainly in adhesion molecules are thought to affect mobilization success. The CD44 is a cell adhesion molecule which is highly heterogeneous structurally. Polymorphisms in this molecule may impair HSC lodgment in the bone marrow.

THE AIM OF THE WORK

was to assess the impact of CD44 single nucleotide polymorphism (rs13347) on the efficacy of mobilization of CD34+ hematopoietic progenitor cells in a cohort of Egyptian patients treated for lymphoma and multiple myeloma and scheduled for autologous stem cell transplantation.

PATIENTS AND METHODS

the study was conducted on 92 patients scheduled for autologous HSC mobilization and transplantation. SNP genotyping was done by 5 ꞌ nuclease assay on rotor gene.

RESULTS

A statistical significant difference was detected between the patients with genotypes (CT + CC) and patients with (TT) genotype regarding the number of apheresis sessions required to gather the target CD34 count (p = 0.006).T allele is implicated in poorer mobilization.

CONCLUSIONS

CD44 SNPs analysis may be helpful for predicting the poor mobilizers. These patients may benefit from newer modalities like adhesion molecules inhibitors.

The effect of serum vitamin B12, folate, ferritin levels and transferrin saturation on stem cell mobilization in allogeneic donors

INTRODUCTION

Peripheric blood derived stem cells are used in 75 % of allogeneic stem cell transplantations. Iron, vitamin B12 and folate involve in hematopoiesis. Therefore serum levels of iron, vitamin B12 and folat may effect stem cell mobilization. We aimed to analyze the effects of iron status, vitamin B12 and folate levels on peripheric blood stem cell mobilization in healthy donors.

METHOD

The mobilization results of 218 allogeneic donors were analyzed retrospectively.

RESULTS

In 64 donors, serum ferritin level was <15 μg / L and transferrin saturation was <20 %. When we compared the donors with iron deficiency to the donors without iron deficiency, the number of collected CD34 + cell was significantly higher in donors without iron deficiency. We did not find any impact of serum vitamin B12 and folate level on CD34+ cells collected.

CONCLUSION

Our study shows that serum ferritin and transferrin saturation have a greater effect on the amount of CD34+ cells collected from donors than serum vitamin B12 and folate levels. Consequently, when compliance tests of allogeneic donors are performed, the evaluation of vitamin B12 and folate levels is not necessary; whereas iron deficiency must be assessed and -if possible- corrected before apheresis is performed.

Inferior prognosis in poor mobilizing myeloma patients

INTRODUCTION

Induction treatment followed by autologous stem cell transplantation (ASCT) has been accepted as the standard treatment for multiple myeloma (MM) patients. Granulocyte colony stimulating agent (G-CSF), chemotherapy or agents likes plerixafor are being used for the mobilization of stem cells from bone marrow. In this study, we evaluated the impact of the mobilization methods on the outcome of MM patients after ASCT.

METHOD

The data of 205 MM patients who underwent ASCT at our center between December 2009 and January 2019 were retrospectively analyzed. Patients were divided into 2 groups as good mobilizers (patients who were mobilized with G-CSF alone) and poor mobilizers (patients who were failed to mobilize with G-CSF alone and mobilized with G-CSF + cylophosphomide or G-CSF + plerixafor).

RESULTS

The median progression free survival (PFS) was 18.27 ± 3.22 months in good mobilizers and 14.22 ± 3.7 months in poor mobilizers. In G-CSF + cyclophosphamide method median PFS was 15.4 ± 4.9 months wheras it was only 4 months in G-CSF + plerixafor method. We did not find a statistically significant difference between good and poor mobilizers regarding median PFS (p: 0.342). The median overall survival (OS) was found 34.48 ± 4.2 months in good mobilizers and 15.13 ± 5.78 months in poor mobilizers. In G-CSF + cyclophosphamide method median OS was 17 ± 14.01 months wheras it was 10.66 ± 7.68 months in G-CSF + plerixafor method. We found a statistically significant difference between good and poor mobilizers regarding median OS (p: 0.007*).

CONCLUSION

Our study shows that difficulty in stem cell mobilization is correlated with worse outcome.

The role of CXCR4 in multiple myeloma: Cells' journey from bone marrow to beyond

CXCR4 is a pleiotropic chemokine receptor which acts through its ligand CXCL12 to regulate diverse physiological processes. CXCR4/CXCL12 axis plays a pivotal role in proliferation, invasion, dissemination and drug resistance in multiple myeloma (MM). Apart from its role in homing, CXCR4 also affects MM cell mobilization and egression out of the bone marrow (BM) which is correlated with distant organ metastasis. Aberrant CXCR4 expression pattern is associated with osteoclastogenesis and tumor growth in MM through its cross talk with various important cell signalling pathways. A deeper insight into understanding of CXCR4 mediated signalling pathways and its role in MM is essential to identify potential therapeutic interventions. The current therapeutic focus is on disrupting the interaction of MM cells with its protective tumor microenvironment where CXCR4 axis plays an essential role. There are still multiple challenges that need to be overcome to target CXCR4 axis more efficiently and to identify novel combination therapies with existing strategies. This review highlights the role of CXCR4 along with its significant interacting partners as a mediator of MM pathogenesis and summarizes the targeted therapies carried out so far.

Bone metabolism markers and angiogenic cytokines as regulators of human hematopoietic stem cell mobilization

Hematopoietic stem cell (HSC) mobilization involves cleavage of ligands between HSC and niche components. However, there are scarce data regarding the role of bone cells in human HSC mobilization. We studied biochemical markers of bone metabolism and angiogenic cytokines during HSC mobilization in 46 patients' sera with lymphoma and multiple myeloma, by ELISA. Significant changes between pre-mobilization and collection samples were found: (1) Bone alkaline phosphatase (BALP) increased, indicating augmentation of bone formation; (2) Receptor activator of Nf-κB ligand/osteoprotegerin ratio (RANKL/OPG) increased, showing osteoclastic differentiation and survival; however, there was no evidence of increased osteoclastic activity; and (3) Angiopoietin-1/Angiopoietin-2 ratio (ANGP-1/ANGP-2) decreased, consistent with vessel destabilization. Poor mobilizers had significantly higher carboxy-terminal telopeptide of collagen type I (CTX) and lower ANGP-1 at pre-mobilization samples, compared to good ones. CTX, amino-terminal telopeptide of collagen type I (NTX) and ANGP-1 pre-mobilization levels correlated significantly with circulating CD34⁺ peak cell counts. Our results indicate that bone formation and vessel destabilization are the two major events during human HSC mobilization. Osteoblasts seem to be the orchestrating cells, while osteoclasts are stimulated but not fully active. Moreover, ANGP-1, CTX and NTX may serve as predictors of poor mobilization.

Expression of adhesion molecules on CD34+ cells from steady-state bone marrow before and after mobilization and their association with the yield of CD34+ cells

Background

Cell adhesion molecules (CAMs) expressed on hematopoietic progenitor cells (HPCs), endothelial cells, and stromal cells play a pivotal role in the mobilization of CD34+ cells. Herein, we conducted a non-randomized peripheral blood stem cell (PBSC) mobilization study aimed to compare the potential differences in the expressions of several CAMs and chemokines on CD34+ cells obtained from bone marrow aspirate before and after HPC mobilization from patients with hematologic malignancies and healthy donors.

Methods

Three-color cytofluorometric analysis was used to compare the expressions of CAMs and chemokines in the bone marrow before and after mobilization.

Results

For all studied groups, CAM expression among those with good and poor yields of CD34+ cells was significantly correlated with VCAM-1 (P=0.007), CD44 (P=0.027), and VLA-4 (P=0.014) expressions. VCAM-1 (P=0.001), FLT-3 (P=0.001), CD44 (P=0.011), VLA-4 (P=0.001), and LFA-1 (P=0.001) expressions were higher before HPC mobilization than after HPC mobilization. By contrast, the expression of CXCR4 significantly varied before and after mobilization only among those with successful PBSC mobilization (P=0.002).

Conclusion

We attempted to identify particular aspects of CAMs involved in CD34+ cell mobilization, which is a highly complex mechanism that involves adhesion molecules and matrix metalloproteases. The mechanism by which CD34+ cell mobilization is activated through proteolytic enzymes is not fully understood. We believe that CXCR4, VLA-4, CD44, and VCAM-1 are the most important molecules implicated in HPC mobilization, particularly because they show a correlation with the yield of CD34+ cells collected via large volume leukapheresis.

MiRNAs and piRNAs from bone marrow mesenchymal stem cell extracellular vesicles induce cell survival and inhibit cell differentiation of cord blood hematopoietic stem cells: a new insight in transplantation

Hematopoietic stem cells (HSC), including umbilical cord blood CD34+ stem cells (UCB-CD34+), are used for the treatment of several diseases. Although different studies suggest that bone marrow mesenchymal stem cells (BM-MSC) support hematopoiesis, the exact mechanism remains unclear. Recently, extracellular vesicles (EVs) have been described as a novel avenue of cell communication, which may mediate BM-MSC effect on HSC. In this work, we studied the interaction between UCB-CD34+ cells and BM-MSC derived EVs. First, by sequencing EV derived miRNAs and piRNAs we found that EVs contain RNAs able to influence UCB-CD34+ cell fate. Accordingly, a gene expression profile of UCB-CD34+ cells treated with EVs, identified about 100 down-regulated genes among those targeted by EV-derived miRNAs and piRNAs (e.g. miR-27b/MPL, miR-21/ANXA1, miR-181/EGR2), indicating that EV content was able to modify gene expression profile of receiving cells. Moreover, we demonstrated that UCB-CD34+ cells, exposed to EVs, significantly changed different biological functions, becoming more viable and less differentiated. UCB-CD34+ gene expression profile also identified 103 up-regulated genes, most of them codifying for chemokines, cytokines and their receptors, involved in chemotaxis of different BM cells, an essential function of hematopoietic reconstitution. Finally, the exposure of UCB-CD34+ cells to EVs caused an increased expression CXCR4, paralleled by an in vivo augmented migration from peripheral blood to BM niche in NSG mice. This study demonstrates the existence of a powerful cross talk between BM-MSC and UCB-CD34+ cells, mediated by EVs, providing new insight in the biology of cord blood transplantation.

New agents in HSC mobilization

Mobilized peripheral blood (PB) is the most common source of hematopoietic stem cells (HSC) for autologous transplantation. Granulocyte colony stimulating factor (G-CSF) is the most commonly used mobilization agent, yet despite its widespread use, a considerable number of patients still fail to mobilize. Recently, a greater understanding of the interactions that regulate HSC homeostasis in the bone marrow (BM) microenvironment has enabled the development of new molecules that mobilize HSC through specific inhibition, modulation or perturbation of these interactions. AMD3100 (plerixafor), a small molecule that selectively inhibits the chemokine receptor CXCR4 is approved for mobilization in combination with G-CSF in patients with Non-Hodgkin's lymphoma and multiple myeloma. Nevertheless, identifying mobilization strategies that not only enhance HSC number, but are rapid and generate an optimal "mobilized product" for improved transplant outcomes remains an area of clinical importance. In recent times, new agents based on recombinant proteins, peptides and small molecules have been identified as potential candidates for therapeutic HSC mobilization. In this review, we describe the most recent developments in HSC mobilization agents and their potential impact in HSC transplantation.

Stem Cell Mobilization with G-CSF versus Cyclophosphamide plus G-CSF in Mexican Children

Fifty-six aphaereses were performed in 23 pediatric patients with malignant hematological and solid tumors, following three different protocols for PBPC mobilization and distributed as follows: A: seventeen mobilized with 4 g/m² of cyclophosphamide (CFA) and 10 μg/kg/day of granulocyte colony stimulating factor (G-CSF), B: nineteen with CFA + G-CSF, and C: twenty only with G-CSF when the WBC count exceeded 10 × 10⁹/L. The average number of MNC/kg body weight (BW)/aphaeresis was 0.4 × 10⁸ (0.1–1.4), 2.25 × 10⁸ (0.56–6.28), and 1.02 × 10⁸ (0.34–2.5) whereas the average number of CD34+ cells/kg BW/aphaeresis was 0.18 × 10⁶/kg (0.09–0.34), 1.04 × 10⁶ (0.19–9.3), and 0.59 × 10⁶ (0.17–0.87) and the count of CFU/kg BW/aphaeresis was 1.11 × 10⁵ (0.31–2.12), 1.16 × 10⁵ (0.64–2.97), and 1.12 × 10⁵ (0.3–6.63) in groups A, B, and C, respectively. The collection was better in group B versus group A (p = 0.007 and p = 0.05, resp.) and in group C versus group A (p = 0.08 and p = 0.05, resp.). The collection of PBPCs was more effective in the group mobilized with CFM + G-CSF when the WBC exceeded 10 × 10³/μL in terms of MNC and CD34+ cells and there was no toxicity of the chemotherapy.

Modern stem cell therapy: approach to disease

Various types of stem cells exist, each with their own advantages and disadvantages. Considering the current available evidence, important preclinical and clinical studies regarding the therapeutic potential of stem cells, stem cell therapy might be the important strategy for tissue repair. The development of stem cell therapy for tissue repair has primarily relied on stem cells, especially mesenchymal stem cells. Multilineage differentiation into all of the described cells are considered as important candidates for a range of diseases like neurological diseases, cardiovascular diseases, gastrointestinal cancer and genetic defects, as well as for acute and chronic wounds healing and pharmaceutical treatment. We review the properties and multipotency of stem cells and their differentiation potential, once cultured under specific growth conditions, for use in cell-based therapies and functional tissue replacement.

Hematopoietic progenitor cell mobilization for autologous transplantation - a literature review

The use of high-dose chemotherapy with autologous support of hematopoietic progenitor cells is an effective strategy to treat various hematologic neoplasms, such as non-Hodgkin lymphomas and multiple myeloma. Mobilized peripheral blood progenitor cells are the main source of support for autologous transplants, and collection of an adequate number of hematopoietic progenitor cells is a critical step in the autologous transplant procedure. Traditional strategies, based on the use of growth factors with or without chemotherapy, have limitations even when remobilizations are performed. Granulocyte colony-stimulating factor is the most widely used agent for progenitor cell mobilization. The association of plerixafor, a C-X-C Chemokine receptor type 4 (CXCR4) inhibitor, to granulocyte colony stimulating factor generates rapid mobilization of hematopoietic progenitor cells. A literature review was performed of randomized studies comparing different mobilization schemes in the treatment of multiple myeloma and lymphomas to analyze their limitations and effectiveness in hematopoietic progenitor cell mobilization for autologous transplant. This analysis showed that the addition of plerixafor to granulocyte colony stimulating factor is well tolerated and results in a greater proportion of patients with non-Hodgkin lymphomas or multiple myeloma reaching optimal CD34⁺ cell collections with a smaller number of apheresis compared the use of granulocyte colony stimulating factor alone.

Granulocyte Colony-Stimulating Factor Induces Osteoblast Inhibition by B Lymphocytes and Osteoclast Activation by T Lymphocytes during Hematopoietic Stem/Progenitor Cell Mobilization

In the bone marrow (BM), hematopoietic stem and progenitor cells (HSPCs) reside in specialized niches near osteoblast cells at the endosteum. HSPCs that egress to peripheral blood are widely used for transplant, and mobilization is most commonly performed with recombinant human granulocyte colony-stimulating factor (G-CSF). However, the cellular targets of G-CSF that initiate the mobilization cascade and bone remodeling are not completely understood. Here, we examined whether T and B lymphocytes modulate the bone niche and influence HSPC mobilization. We used T and B defective mice to show that G-CSF-induced mobilization of HSPCs correlated with B lymphocytes but poorly with T lymphocytes. In addition, we found that defective B lymphocytes prevent G-CSF-mediated osteoblast disruption, and further study showed BM osteoblasts were reduced coincident with mobilization, induced by elevated expression of dickkopf1 of BM B lymphocytes. BM T cells were also involved in G-CSF-induced osteoclast activation by regulating the Receptor Activator of Nuclear Factor-κ B Ligand/Osteoprotegerin (RANKL/OPG) axis. These data provide evidence that BM B and T lymphocytes play a role in G-CSF-induced HSPC mobilization by regulating bone remodeling.