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Neutrophils are the most frequent immune cell type in peripheral blood, performing an essential role against pathogens. People with neutrophil deficiencies are susceptible to deadly infections, highlighting the importance of generating these cells in host immunity. Neutrophils can be generated from hematopoietic progenitor cells (HPCs) and embryonic stem cells (ESCs) using a cocktail of cytokines. In addition, induced pluripotent stem cells (iPSCs) can be differentiated into various functional cell types, including neutrophils. iPSCs can be derived from differentiated cells, such as skin and blood cells, by reprogramming them to a pluripotent state. Neutrophil generation from iPSCs involves a multistep process that can be performed through feeder cell-dependent and feeder cell-independent manners. Various cytokines and growth factors, in particular, stem cell facto, IL-3, thrombopoietin and granulocyte colony-stimulating factor (G-CSF), are used in both methods, especially, G-CSF which induces the final differentiation of neutrophils in the granulocyte lineage. iPSC-derived neutrophils have been used as a valuable tool for studying rare genetic disorders affecting neutrophils. The iPSC-derived neutrophils can also be used for disease modeling, infection research and drug discovery. However, several challenges must be overcome before iPSC-derived neutrophils can be used therapeutically in transplantation medicine. This review provides an overview of the commonly employed protocols for generating neutrophils from HPCs, ESCs and iPSCs and discusses the potential applications of the generated cells in research and medicine. [Display omitted] • Neutrophils have been successfully differentiated from hematopoietic progenitor cells and iPSCs. • Neutrophil generation from iPSCs has been done via feeder cell-dependent and independent manners. • iPSC-derived neutrophils have been used for studying various neutrophil genetic disorders. • iPSC-derived neutrophils can be used for effective adoptive cellular therapy, drug development and disease modeling. [ABSTRACT FROM AUTHOR]

The liver plays an essential role in the metabolism of animals, acting as a central hub for metabolic reactions. It serves as a “peripheral integrator” and balances the body’s energy needs. Its regenerative capacity is remarkably high and is maintained by the proliferation of hepatocytes, as well as hematopoietic and regional liver progenitor cells (LPC). This study investigated LPC-driven liver regeneration during postembryonic development in Rana terrestris under normal physiological conditions. The analysis of intrahepatic and hematopoietic markers by immunohistochemistry and flow cytometry revealed that progenitor cells with the immunophenotypes of CK19+ (intrahepatic progenitor cells), CD34+CD45+ (hematopoietic progenitor cell population), and CD34+CD45– (hemangioblast population) equally promote liver regeneration during the first year of postembryonic development. However, in the second and third years of postembryonic development, liver regeneration was found to be primarily associated with CK19+-positive cells, with a smaller contribution from CD34+CD45– cells. The results obtained were largely determined by the habitat of the amphibians, thermoregulation, and the completion of morphogenetic processes in the third year of postembryonic development. It is also noteworthy that the liver of the examined specimens remained the major hematopoietic organ throughout all observed stages of postembryonic development.

Hematopoiesis is a process by which all blood cells are formed. The mechanisms controlling it have been studied for decades. Surprisingly, while hematopoietic stem cells are among the most extensively studied stem cell types, the complete understanding of how they are regulated during development, adulthood, or in non-homeostatic conditions remains elusive. In this review, our primary focus is on research findings that explore where hematopoietic precursors are found in adults outside their primary niches in the bone marrow. This phenomenon is termed extramedullary hematopoiesis (EMH). Early in development hematopoietic stem cells migrate through different regions within and outside the embryo and later the fetus. Although, the primary home for hematopoietic progenitors is the adult bone marrow, it is now recognized that other adult organs may act as hematopoietic progenitor reservoirs both in mice and humans. The first reports about this topic were principally originated from clinical observations, in cases where the bone marrow was malfunctioning, leading to an aberrant hematopoiesis outside the bone marrow. It is worth highlighting that those extramedullary organs, like the small intestine or fat tissue, contain subsets of fully functioning hematopoietic progenitors demonstrated by both in vitro and in vivo studies. Nonetheless, there are still some unanswered questions regarding the source of these cells, how they differ in function compared to their counterparts in the bone marrow, and the specific roles they play within the tissues where they are located.

Extensive research has explored the functional correlation between stem cells and progenitor cells, particularly in blood. Hematopoietic stem cells (HSCs) can self-renew and regenerate tissues within the bone marrow, while stromal cells regulate tissue function. Recent studies have validated the role of mammalian stem cells within specific environments, providing initial empirical proof of this functional phenomenon. The interaction between bone and blood has always been vital to the function of the human body. It was initially proposed that during evolution, mammalian stem cells formed a complex relationship with the surrounding microenvironment, known as the niche. Researchers are currently debating the significance of molecular-level data to identify individual stromal cell types due to incomplete stromal cell mapping. Obtaining these data can help determine the specific activities of HSCs in bone marrow. This review summarizes key topics from previous studies on HSCs and their environment, discussing current and developing concepts related to HSCs and their niche in the bone marrow.

The development and functional potential of metazoan cells is dependent on combinatorial roles of transcriptional enhancers and promoters. Macrophages provide exceptionally powerful model systems for investigation of mechanisms underlying the activation of cell-specific enhancers that drive transitions in cell fate and cell state. Here, we review recent advances that have expanded appreciation of the diversity of macrophage phenotypes in health and disease, emphasizing studies of liver, adipose tissue, and brain macrophages as paradigms for other tissue macrophages and cell types. Studies of normal tissue-resident macrophages and macrophages associated with cirrhosis, obese adipose tissue, and neurodegenerative disease illustrate the major roles of tissue environment in remodeling enhancer landscapes to specify the development and functions of distinct macrophage phenotypes. We discuss the utility of quantitative analysis of environment-dependent changes in enhancer activity states as an approach to discovery of regulatory transcription factors and upstream signaling pathways.

Sufficient doses of viable CD34+ (vCD34) hematopoietic progenitor cells (HPCs) are crucial for engraftment. Additional-day apheresis collections can compensate for potential loss during cryopreservation but incur high cost and additional risk. To aid predicting such losses for clinical decision support, we developed a machine-learning model using variables obtainable on the day of collection. In total, 370 consecutive autologous HPCs, apheresis-collected since 2014 at the Children's Hospital of Philadelphia, were retrospectively reviewed. Flow cytometry was used to assess vCD34% on fresh products and thawed quality control vials. The ratio of vCD34% thawed to fresh, which we call "post-thaw index," was used as an outcome measure, with a "poor" post-thaw index defined as <70%. HPC CD45 normalized mean fluorescence intensity (MFI) was calculated by dividing CD45 MFI of HPCs to the CD45 MFI of lymphocytes in the same sample. We trained XGBoost, k -nearest neighbor and random forest models for the prediction and calibrated the best model to minimize falsely-reassuring predictions. In total, 63 of 370 (17%) products had a poor post-thaw index. The best model was XGBoost, with an area under the receiver operator curve of 0.83 evaluated on an independent test data set. The most important predictor for a poor post-thaw index was the HPC CD45 normalized MFI. Transplants after 2015, based on the lower of the two vCD34% values, showed faster engraftment than older transplants, which were based on fresh vCD34% only (average 10.6 vs 11.7 days, P = 0.0006). Transplants taking into account post-thaw vCD34% improved engraftment time in our patients; however, it came at the cost of unnecessary multi-day collections. The results from applying our predictive algorithm retrospectively to our data suggest that more than one-third of additional-day collections could have been avoided. Our investigation also identified CD45 nMFI as a novel marker for assessing HPC health post-thaw. [ABSTRACT FROM AUTHOR]

Peripheral blood hematopoietic progenitor cell harvest by apheresis in pediatric patients, a double-edged sword, has advantages and disadvantages over conventional bone marrow transplantation. The effect of granulocyte colony-stimulating factor (G-CSF) mobilization on hemostasis in literature is very scarce. A 3-year-old female child with metastatic neuroblastoma planned for autologous transplant. Following G-CSF mobilization (75 mg; 4 days), the procedure was performed with all default parameters in Spectra Optia with an acid citrate dextrose (ACD) flow rate 1:12, assuming 3-total blood volume (TBV) to be processed with 150 ml of expected collection with target yield of 6 x 106 CD34 cells/kg. Despite normal coagulation laboratory parameters, it was abandoned for reasons such as low-flow alarms and thrombi in the kit tubings. In the subsequent procedures, the ACD to whole blood ratio was decreased to 1:16, and used bolus of heparin was followed by continuous heparin infusion throughout the procedure. Despite using heparin anticoagulation, a long thrombus was aspirated at needleless port. The procedure was completed with continuous low-flow alarms. A cumulative dose of 5.67 x 106 CD34 cells/kg was achieved over four procedures, but the cause of hypercoagulability was unknown. All the coagulation parameters were within normal limits before and after the procedure. The exact cause for hypercoagulability remains elusive. There are no studies or case reports in the pediatric population on hypercoagulability following apheresis procedure after G-CSF mobilization, but evidence is available for adults, with lack of explanation. It can also be due to low draw flow from the patient side or embolization of thrombi developed in the anticoagulant unprimed site in the kit tubings. More extensive studies are required to explain the mechanism of hypercoagulability during apheresis procedures in the pediatric population. [ABSTRACT FROM AUTHOR]

Aging-related anemia contributes to frailty syndrome, cognitive decline and early mortality. The study aim was to evaluate inflammaging in relation to anemia as a prognostic indicator in affected older patients. The participants (73.0 ± 7.2 years) were allocated into anemic (n = 47) and non-anemic (n = 66) groups. The hematological variables RBC, MCV, MCH, RDW, iron and ferritin were significantly lower, whereas erythropoietin EPO and transferrin Tf tended toward higher values in the anemic group. Approx. 26% of individuals demonstrated transferrin saturation TfS < 20%, which clearly indicates age-related iron deficiency. The cut-off values for pro-inflammatory cytokine IL-1β, TNFα and hepcidin were 5.3 ng/mL, 97.7 ng/mL and 9.4 ng/mL, respectively. High IL-1β negatively affected Hb concentration (rs = −0.581, p < 0.0001). Relatively high odds ratios were observed for IL-1β (OR = 72.374, 95%Cl 19.688–354.366) and peripheral blood mononuclear cells CD34 (OR = 3.264, 95%Cl 1.263–8.747) and CD38 (OR = 4.398, 95%Cl 1.701–11.906), which together indicates a higher probability of developing anemia. The results endorse the interplay between inflammatory status and iron metabolism and demonstrated a high usefulness of IL-1β in identification of the underlying causes of anemia, while CD34 and CD38 appeared useful in compensatory response assessment and, in the longer term, as part of a comprehensive approach to anemia monitoring in older adults. [ABSTRACT FROM AUTHOR]

Historically, the immune system was believed to develop along a linear axis of maturity from fetal life to adulthood. Now, it is clear that distinct layers of immune cells are generated from unique waves of hematopoietic progenitors during different windows of development. This model, known as the layered immune model, has provided a useful framework for understanding why distinct lineages of B cells and γδ T cells arise in succession and display unique functions in adulthood. However, the layered immune model has not been applied to CD8+ T cells, which are still often viewed as a uniform population of cells belonging to the same lineage, with functional differences between cells arising from environmental factors encountered during infection. Recent studies have challenged this idea, demonstrating that not all CD8+ T cells are created equally and that the functions of individual CD8+ T cells in adults are linked to when they were created in the host. In this review, we discuss the accumulating evidence suggesting there are distinct ontogenetic subpopulations of CD8+ T cells and propose that the layered immune model be extended to the CD8+ T cell compartment. [ABSTRACT FROM AUTHOR]

Peripheral blood hematopoietic progenitor cell harvest by apheresis in pediatric patients, a double-edged sword, has advantages and disadvantages over conventional bone marrow transplantation. The effect of granulocyte colony-stimulating factor (G-CSF) mobilization on hemostasis in literature is very scarce. A 3-year-old female child with metastatic neuroblastoma planned for autologous transplant. Following G-CSF mobilization (75 mg; 4 days), the procedure was performed with all default parameters in Spectra Optia with an acid citrate dextrose (ACD) flow rate 1:12, assuming 3-total blood volume (TBV) to be processed with 150 ml of expected collection with target yield of 6 × 106 CD34 cells/kg. Despite normal coagulation laboratory parameters, it was abandoned for reasons such as low-flow alarms and thrombi in the kit tubings. In the subsequent procedures, the ACD to whole blood ratio was decreased to 1:16, and used bolus of heparin was followed by continuous heparin infusion throughout the procedure. Despite using heparin anticoagulation, a long thrombus was aspirated at needleless port. The procedure was completed with continuous low-flow alarms. A cumulative dose of 5.67 × 106 CD34 cells/kg was achieved over four procedures, but the cause of hypercoagulability was unknown. All the coagulation parameters were within normal limits before and after the procedure. The exact cause for hypercoagulability remains elusive. There are no studies or case reports in the pediatric population on hypercoagulability following apheresis procedure after G-CSF mobilization, but evidence is available for adults, with lack of explanation. It can also be due to low draw flow from the patient side or embolization of thrombi developed in the anticoagulant unprimed site in the kit tubings. More extensive studies are required to explain the mechanism of hypercoagulability during apheresis procedures in the pediatric population.

Background and purpose: Human pluripotent stem cells (hPSCs) with the ability to differentiate into adult cells have provided a new perspective for treatment of some diseases. But, the efficiency of differentiation methods to generate hematopoietic progenitor cells (HPCs) is faced with multiple challenges. In the present study, we investigated the formation of hemato-endothelial-like structures and HPCs from hPSCs. Materials and methods: To generate hemato-endothelial structures and HPCs, in first method, three-dimensional aggregations of hPSCs were co-cultured on OP9 cells. In second and third methods, embryoid bodies (EBs) were differentiated spontaneously or directly in the culture medium containing BMP4, bFGF, SCF, and VEGF. In differentiation process, cell morphology was evaluated by microscopic observation and the expression of CD34 and CD45 markers were analyzed by flow cytometry. In addition, the ability of HPCs to differentiate into various types of blood cells was evaluated using colony formation assay, Wright-Giemsa staining, and CD86 immunofluorescence staining. Results: Findings showed that all three methods generated cells with endothelial-like morphology and HPCs. These cells were able to proliferate, form cell clusters with different efficiency and differentiate into erythroid cells, macrophages, and dendritic cells. Conclusion: The use of cultured cells in defined conditions without a feeder layer is preferred in cell therapy. Therefore, despite the ability of all these methods to generate HPCs, direct differentiation of EBs under defined conditions is a better option for generatingHPCs from hPSCs.

Objectives To establish a reliable XN-HPC cutoff, for an effective CD34 + cell count of ≥2 × 106cells/kg of the recipient’s body weight, in harvested bone marrow products in allogenic transplantation. Methods The study was carried out in two phases. In retrospective Phase 1, data from 47 donors were analyzed. Sysmex analyzer XN-20 and BD FACS Calibur were employed to process XN-HPC and CD34 + cell enumeration, respectively. To make the two variables comparable, both XN-HPC and CD34 + cell counts were reported as the number of cells/kg of the recipient’s body weight. Spearman’s rank correlation coefficient was calculated for CD34 + cells and XN-HPC, followed by the calculation of the receiver operating characteristic (ROC) curve to identify the XN-HPC value which could effectively predict the cutoff of ≥2 × 106 CD34 + cells/kg of the recipient’s body weight. In Phase 2, the computed XN-HPC cutoff was validated in a prospective set of 53 donors by obtaining the positive and negative predictive values. Results Statistically significant correlation was obtained between XN-HPC and CD34 + cell count with Spearman’s rho of 0.54 (p-value

Abstract Background Autologous hematopoietic progenitor cell (HPC) transplantation is currently the standard of care for a fraction of patients with newly diagnosed myelomas and relapsed or refractory lymphomas. After high-dose chemotherapy, cryopreserved HPC are either infused directly after bedside thawing or washed and concentrated before infusion. We previously reported on the comparability of washing/concentrating HPC post-thaw vs. infusion without manipulation in terms of hematopoietic engraftment, yet settled for the prior favoring cell debris and DMSO removal. For almost two decades, automation of this critical step of washing/concentrating cells has been feasible. As part of continuous process verification, we aim to evaluate reproducibility of this procedure by assessing intra-batch and inter-batch variability upon concentration of thawed HPC products using the Sepax 2 S-100 cell separation system. Methods Autologous HPC collected from the same patient were thawed and washed either in two batches processed within a 3-4 h interval and immediately infused on the same day (intra-batch, n = 45), or in two batches on different days (inter-batch, n = 49) for those patients requiring 2 or more high-dose chemotherapy cycles. Quality attributes assessed were CD34+ cell recovery, viability and CD45+ viability; CFU assay was only performed for allogeneic grafts. Results Intra-batch and inter-batch median CD34+ cell recovery was comparable (75% vs. 73% and 77% vs. 77%, respectively). Similarly, intra-batch and inter-batch median CD45+ cell viability was comparable (79% vs. 80% and 79% vs. 78%, respectively). Bland-Altman analysis describing agreement between batches per patient revealed a bias close to 0%. Additionally, lower HPC recoveries noted in batch 1 were noted as well in batch 2, regardless of the CD34+ cell dose before cryopreservation, both intra- and inter-batch, suggesting that the quality of the collected product plays an important role in downstream recovery. Intrinsic (high mature and immature granulocyte content) and extrinsic (delay between apheresis and cryopreservation) variables of the collected product resulted in a significantly lower CD45+ viability and CD34+ cell recovery upon thawing/washing. Conclusions Automated post-thaw HPC concentration provides reproducible cell recoveries and viabilities between different batches. Implications of this work go beyond HPC to concentrate cell suspension/products during manufacturing of cell and gene therapy products.

Objective: DUX4 is an embryonic transcription factor (TF) later silenced in somatic tissues, while active in germline testis cells. Re-expression in somatic cells has been revealed to be present in pathologic conditions such as dystrophy, leukemia, and other cancer types. Embryonic cells, cancer cells and testis cells that show DUX4 expression are pluri-multipotent cells. This lead us to question �Could DUX4 be a TF that is active in certain types of potent somatic cells?� As a perfect reflection of the potent cell pool, we aimed to reveal DUX4 expression in the bone marrow. Material and Method: Bone marrow aspiration materials of seven healthy donors aged between 3 and 32 (2 males/5 females) were investigated with qPCR analysis after RNA isolation for the presence of DUX4 full length mRNA expression. Samples have been investigated for protein existence of DUX4 via immunohistochemistry in two donors that had sufficient aspiration material. Results: DUX4 mRNA expression was present in all donors, with higher expression compared to B-actin. DUX4 positive stained cells were also detected by immunohistochemistry. Conclusion: With these results, novel expression for DUX4 in hematopoietic tissue is described. Further studies on the function of DUX4 in hematopoietic cells can shed light on DUX4-related pathways, and contribute to the treatment of DUX4-related diseases such as B-ALL, other cancers, and facioscapulohumeral muscular dystrophy.

Abstract Background The increasing number of clinical trials for induced pluripotent stem cell (iPSC)-derived cell therapy products makes the production on clinical grade iPSC more and more relevant and necessary. Cord blood banks are an ideal source of young, HLA-typed and virus screened starting material to produce HLA-homozygous iPSC lines for wide immune-compatibility allogenic cell therapy approaches. The production of such clinical grade iPSC lines (haplolines) involves particular attention to all steps since donor informed consent, cell procurement and a GMP-compliant cell isolation process. Methods Homozygous cord blood units were identified and quality verified before recontacting donors for informed consent. CD34+ cells were purified from the mononuclear fraction isolated in a cell processor, by magnetic microbeads labelling and separation columns. Results We obtained a median recovery of 20.0% of the collected pre-freezing CD34+, with a final product median viability of 99.1% and median purity of 83.5% of the post-thawed purified CD34+ population. Conclusions Here we describe our own experience, from unit selection and donor reconsenting, in generating a CD34+ cell product as a starting material to produce HLA-homozygous iPSC following a cost-effective and clinical grade-compliant procedure. These CD34+ cells are the basis for the Spanish bank of haplolines envisioned to serve as a source of cell products for clinical research and therapy.

BACKGRAUND: There is evidence that the adverse effects of metamizole occur due to the effect of the drug on the hematopoietic stem/progenitor cells, and therefore, the disruption of hematopoiesis. Therefore, our study aimed to evaluate the effects of metamizole on hematopoietic stem/progenitor cells using cell culture techniques. MATERIAL AND METHODS: In our study, samples were taken from stem cell products of healthy allogeneic stem cell transplant donors. The colony-forming unit (CFU) assay was used for the cells obtained from these samples. In addition, the drug effects on cell proliferation were evaluated with the MTT. Furthermore, the cell colonies were labelled with immunofluorescent antibodies and the effects of metamizole on cell types formed in culture were evaluated. RESULTS: We determined that metamizole negatively affects the proliferation of cells, especially starting from 10 µM. As a result of the evaluation of colonization, we saw that the number of colonies decreased with increasing concentrations. Granulocyte-macrophage colonies were more affected at increasing concentrations than other colonies. As a result of the evaluations of our in vitro study, it was also shown as an important finding that the individual effects of the drug were highly variable. CONCLUSION: CFU method can be used as a suitable method to investigate the effects of drugs and toxic substances on hematopoiesis. We also think it may be suitable for pre-analysing hematopoietic side effects in new drug research. In addition, using stem cell samples in studies may contribute more easily to the in vitro simulation of hematopoietic differentiations. [ABSTRACT FROM AUTHOR]

Background and purpose: Human pluripotent stem cells (hPSCs) with the ability to differentiate into adult cells have provided a new perspective for treatment of some diseases. But, the efficiency of differentiation methods to generate hematopoietic progenitor cells (HPCs) is faced with multiple challenges. In the present study, we investigated the formation of hemato-endothelial-like structures and HPCs from hPSCs. Materials and methods: To generate hemato-endothelial structures and HPCs, in first method, three-dimensional aggregations of hPSCs were co-cultured on OP9 cells. In second and third methods, embryoid bodies (EBs) were differentiated spontaneously or directly in the culture medium containing BMP4, bFGF, SCF, and VEGF. In differentiation process, cell morphology was evaluated by microscopic observation and the expression of CD34 and CD45 markers were analyzed by flow cytometry. In addition, the ability of HPCs to differentiate into various types of blood cells was evaluated using colony formation assay, Wright-Giemsa staining, and CD86 immunofluorescence staining. Results: Findings showed that all three methods generated cells with endothelial-like morphology and HPCs. These cells were able to proliferate, form cell clusters with different efficiency and differentiate into erythroid cells, macrophages, and dendritic cells. Conclusion: The use of cultured cells in defined conditions without a feeder layer is preferred in cell therapy. Therefore, despite the ability of all these methods to generate HPCs, direct differentiation of EBs under defined conditions is a better option for generatingHPCs from hPSCs. [ABSTRACT FROM AUTHOR]

To establish a reliable XN-HPC cutoff, for an effective CD34 + cell count of ≥2 × 106cells/kg of the recipient's body weight, in harvested bone marrow products in allogenic transplantation. The study was carried out in two phases. In retrospective Phase 1, data from 47 donors were analyzed. Sysmex analyzer XN-20 and BD FACS Calibur were employed to process XN-HPC and CD34 + cell enumeration, respectively. To make the two variables comparable, both XN-HPC and CD34 + cell counts were reported as the number of cells/kg of the recipient's body weight. Spearman's rank correlation coefficient was calculated for CD34 + cells and XN-HPC, followed by the calculation of the receiver operating characteristic (ROC) curve to identify the XN-HPC value which could effectively predict the cutoff of ≥2 × 106 CD34 + cells/kg of the recipient's body weight. In Phase 2, the computed XN-HPC cutoff was validated in a prospective set of 53 donors by obtaining the positive and negative predictive values. Statistically significant correlation was obtained between XN-HPC and CD34 + cell count with Spearman's rho of 0.54 (p-value <0.001). The optimal XN-HPC cutoff, for the required CD34 + ve cell count of ≥2 × 106 cells/kg of the recipient's body weight, was calculated to be ≥2.80×106 cells/kg of the recipient's body weight with the specificity and sensitivity of 100% and 31%, respectively. The ROC curve demonstrated the area under the curve to be 0.74. Phase 2 validation revealed 100% PPV. For harvested bone marrow products with XN-HPC of ≥2.80×106 cell/kg of the recipient's body weight, CD34 + cell enumeration by flow cytometry can safely be disposed of. [ABSTRACT FROM AUTHOR]

Background: Autologous hematopoietic progenitor cell (HPC) transplantation is currently the standard of care for a fraction of patients with newly diagnosed myelomas and relapsed or refractory lymphomas. After high-dose chemotherapy, cryopreserved HPC are either infused directly after bedside thawing or washed and concentrated before infusion. We previously reported on the comparability of washing/concentrating HPC post-thaw vs. infusion without manipulation in terms of hematopoietic engraftment, yet settled for the prior favoring cell debris and DMSO removal. For almost two decades, automation of this critical step of washing/concentrating cells has been feasible. As part of continuous process verification, we aim to evaluate reproducibility of this procedure by assessing intra-batch and inter-batch variability upon concentration of thawed HPC products using the Sepax 2 S-100 cell separation system.Methods: Autologous HPC collected from the same patient were thawed and washed either in two batches processed within a 3-4 h interval and immediately infused on the same day (intra-batch, n = 45), or in two batches on different days (inter-batch, n = 49) for those patients requiring 2 or more high-dose chemotherapy cycles. Quality attributes assessed were CD34+ cell recovery, viability and CD45+ viability; CFU assay was only performed for allogeneic grafts.Results: Intra-batch and inter-batch median CD34+ cell recovery was comparable (75% vs. 73% and 77% vs. 77%, respectively). Similarly, intra-batch and inter-batch median CD45+ cell viability was comparable (79% vs. 80% and 79% vs. 78%, respectively). Bland-Altman analysis describing agreement between batches per patient revealed a bias close to 0%. Additionally, lower HPC recoveries noted in batch 1 were noted as well in batch 2, regardless of the CD34+ cell dose before cryopreservation, both intra- and inter-batch, suggesting that the quality of the collected product plays an important role in downstream recovery. Intrinsic (high mature and immature granulocyte content) and extrinsic (delay between apheresis and cryopreservation) variables of the collected product resulted in a significantly lower CD45+ viability and CD34+ cell recovery upon thawing/washing.Conclusions: Automated post-thaw HPC concentration provides reproducible cell recoveries and viabilities between different batches. Implications of this work go beyond HPC to concentrate cell suspension/products during manufacturing of cell and gene therapy products. [ABSTRACT FROM AUTHOR]

Development of new and improvement of existing models of long-term cultivation of hematopoietic stem cells (HSC) and cord blood progenitor cells is one of the most important directions in modern cell biology, related to obtaining a sufficient amount of hematopoietic tissue for experimental and clinical use. The aim of the work was to investigate the functional activity of hematopoietic progenitor cells from cord blood during long-term cultivation on a soft polyacrylamide gel substrate in the presence of a cytokine complex and to determine the advantages of this method of maintaining hematopoiesis for further use in transplantation. To realize this purpose, the following methods were used: the method of long-term cultivation in vitro on a hydrogel substrate, the method of colony formation in semi-liquid agar, cytological research methods, light and inverted microscopy, statistical research methods. Due to the use of the hydrogel substrate together with the cytokine complex, a high proliferative activity of hematopoietic cells is observed, which is reflected in their expansion during long-term cultivation (5 weeks), as well as of high colony-forming activity (521.5 ± 7.5.105 per explanted cells). Thus, the stiffness of the substrate must be taken into account for the expansion of stem cells and their immediate descendants. The presence of a soft substrate made of polyacrylamide gel along with a complex of cytokines ensures the expansion of hematopoietic cells due to the longterm support of hematopoiesis. [ABSTRACT FROM AUTHOR]

Physical signals provided by the extracellular matrix (ECM) are key microenvironmental parameters for the fate decision of hematopoietic stem and progenitor cells (HSPC) in bone marrow. Insights into cell-ECM interactions are critical for advancing HSC-based tissue engineering. Herein, we employed collagen hydrogels and collagen-alginate hydrogels of defined stiffness to study the behaviors of hematopoietic progenitor cells (HPCs). Three-dimensional (3D) collagen hydrogels with a stiffness of 45 Pa were found to promote HPC maintenance and colony formation of monocyte/macrophage progenitors. Using single-cell RNA sequencing (scRNA-seq), we also characterized the comprehensive transcriptional profiles of cells randomly selected from two-dimensional (2D) and 3D hydrogels. A distinct maturation trajectory from HPCs into macrophages within the 3D microenvironment was revealed by these results. 3D-derived macrophages expressed high levels of various cytokines and chemokines, such as Saa3, Cxcl2, Socs3 and Tnf. Furthermore, enhanced communication between 3D-macrophages and other hematopoietic clusters based on ligand-repair interactions was demonstrated through bioinformatic analyses. Our research underlines the regulatory role of matrix-dimensionality in HPC differentiation and therefore probably be applied to the generation of specialized macrophages.

Hematopoietic stem cells (HSCs) in bone marrow continuously supply a large number of blood cells throughout life in collaboration with hematopoietic progenitor cells (HPCs). HSCs and HPCs are thought to regulate and utilize intracellular metabolic programs to obtain metabolites, such as adenosine triphosphate (ATP), which is necessary for various cellular functions. Metabolites not only provide stem/progenitor cells with nutrients for ATP and building block generation but are also utilized for protein modification and epigenetic regulation to maintain cellular characteristics. In recent years, the metabolic programs of tissue stem/progenitor cells and their underlying molecular mechanisms have been elucidated using a variety of metabolic analysis methods. In this review, we first present the advantages and disadvantages of the current approaches applicable to the metabolic analysis of tissue stem/progenitor cells, including HSCs and HPCs. In the second half, we discuss the characteristics and regulatory mechanisms of HSC metabolism, including the decoupling of ATP production by glycolysis and mitochondria. These technologies and findings have the potential to advance stem cell biology and engineering from a metabolic perspective and to establish therapeutic approaches. [ABSTRACT FROM AUTHOR]

Background: Autologous stem cell transplantation is the standard procedure for multiple myeloma and the grafts are usually cryopreserved. Previous studies reported advantages in the use of fresh peripheral blood stem cells (PBSC) autotransplantation compared to cryopreservation of the grafts. This study compared the transplant-related outcomes of two graft preservation methods: fresh storage (4°C/72 h) and cryopreservation (-80°C).Study Design and Methods: We performed an analysis of 45 patients with multiple myeloma under autotransplantation (17 fresh and 28 cryopreserved) from 2017 to 2021. Fresh PBSC were maintained in the refrigerator for three days in a concentration up to 300 × 103 TNC/μL. Cryopreserved PBSC were concentrated by plasma reduction after centrifugation (950 g/10 min/4°C) and an equal volume of cryoprotection solution was added for a final concentration of 300 × 103 TNC/μL, 5% DMSO, 6% hydroxyethyl starch, and 3% human albumin.Results: Neutrophil engraftment was significantly faster with fresh PBSCs (10 vs. 11.5 days, p = 0.045). Adverse effects were more common in cryopreserved PBSC transplantation (75% vs. 35.3% patients; p = 0.013). Post transplantation hospital stay was 20 and 22 days for fresh and cryopreserved PBSCs respectively (p = 0.091). There was no difference in platelet engraftment time (10.5 days for both; p = 0.133), number of antibiotics used after transplantation (3 for fresh and 2.5 for cryopreserved; p = 0.828), days of antibiotic use after transplantation (12.2 days for fresh and 13.3 days for cryopreserved, p = 0.579), and overall survival (p = 0.736).Conclusion: The infusion of fresh PBSC refrigerated for up to three days is effective and safe for autologous transplantation in patients with multiple myeloma, which is a useful alternative to cryopreserved PBSC. [ABSTRACT FROM AUTHOR]

Objective: DUX4 is an embryonic transcription factor (TF) later silenced in somatic tissues, while active in germline testis cells. Re-expression in somatic cells has been revealed to be present in pathologic conditions such as dystrophy, leukemia, and other cancer types. Embryonic cells, cancer cells and testis cells that show DUX4 expression are pluri-multipotent cells. This lead us to question "Could DUX4 be a TF that is active in certain types of potent somatic cells?" As a perfect reflection of the potent cell pool, we aimed to reveal DUX4 expression in the bone marrow. Material and Method: Bone marrow aspiration materials of seven healthy donors aged between 3 and 32 (2 males/5 females) were investigated with qPCR analysis after RNA isolation for the presence of DUX4 full length mRNA expression. Samples have been investigated for protein existence of DUX4 via immunohistochemistry in two donors that had sufficient aspiration material. Results: DUX4 mRNA expression was present in all donors, with higher expression compared to B-actin. DUX4 positive stained cells were also detected by immunohistochemistry. Conclusion: With these results, novel expression for DUX4 in hematopoietic tissue is described. Further studies on the function of DUX4 in hematopoietic cells can shed light on DUX4-related pathways, and contribute to the treatment of DUX4-related diseases such as B-ALL, other cancers, and facioscapulohumeral muscular dystrophy. [ABSTRACT FROM AUTHOR]

Background: The increasing number of clinical trials for induced pluripotent stem cell (iPSC)-derived cell therapy products makes the production on clinical grade iPSC more and more relevant and necessary. Cord blood banks are an ideal source of young, HLA-typed and virus screened starting material to produce HLA-homozygous iPSC lines for wide immune-compatibility allogenic cell therapy approaches. The production of such clinical grade iPSC lines (haplolines) involves particular attention to all steps since donor informed consent, cell procurement and a GMP-compliant cell isolation process. Methods: Homozygous cord blood units were identified and quality verified before recontacting donors for informed consent. CD34+ cells were purified from the mononuclear fraction isolated in a cell processor, by magnetic microbeads labelling and separation columns. Results: We obtained a median recovery of 20.0% of the collected pre-freezing CD34+, with a final product median viability of 99.1% and median purity of 83.5% of the post-thawed purified CD34+ population. Conclusions: Here we describe our own experience, from unit selection and donor reconsenting, in generating a CD34+ cell product as a starting material to produce HLA-homozygous iPSC following a cost-effective and clinical grade-compliant procedure. These CD34+ cells are the basis for the Spanish bank of haplolines envisioned to serve as a source of cell products for clinical research and therapy. [ABSTRACT FROM AUTHOR]

Hematopoietic stem cells (HPCs) donors mobilized by granulocyte‐colony‐stimulating factor (G‐CSF) can develop various signs and symptoms. proBNP (pro‐B‐type natriuretic peptide) is a serum marker of heart failure. A donor who developed severe adverse reactions after G‐CSF mobilization was found to have high serum proBNP levels. We followed additional donors who received identical mobilization regimen to investigate the prevalence of this phenomenon. Eighteen healthy donors underwent a mobilization regimen of 10 μg/Kg G‐CSF daily for 5 days prior to allogeneic HPC collection using Spectra Optia between January 2016 and February 2017 were included in this study. Serum proBNP levels were measured before and after G‐CSF stimulation and immediately after apheresis. Apheresis collection parameters and other laboratory results were also reviewed. The majority of donors (86.7%) had post‐G‐CSF elevation of serum proBNP. Seven of those had elevated proBNP above upper normal range (124 pg/ml). The subgroup of donors with normal proBNP is younger (median age of 37 vs 42 years), with majority being male (90.9% vs 28.6%) and with smaller processed blood volume (2.2 vs 3 × total blood volume). This case series demonstrates an increase of serum proBNP can be common in HPC donors stimulated with 5 days of 10 mcg/kg G‐CSF. This is an adverse reaction that has not been described before. The temporary elevation of proBNP in these donors is not associated with ventricular dysfunction of the heart. The risk factors for marked elevation of proBNP post‐G‐CSF should be further investigated. [ABSTRACT FROM AUTHOR]

Hematopoietic progenitor cells (HPCs) in bone marrow with limited abilities for self-renewal and differentiation continuously supply hematopoietic cells through life. When suffering infection or inflammation, HPCs will actively proliferate to provide differentiated hematopoietic cells to maintain hematopoietic homeostasis. Poly(I:C), an agonist of TLR3, can specifically activate Type I interferon (IFN-I) signaling which exerts anti-inflammatory effects and influence hematopoiesis after infection. However, the effects of Poly(I:C)-induced IFN-I on the bone marrow hematopoietic system still deserve attention. In this study, our results revealed the efficacy of the IFN-I model, with a remarkably decrease in HPCs and a sharp elevation in LSKs numbers after single dose of Poly(I:C) injection. Apoptotic ratios of HPCs and LSKs significantly increased 48 h after Poly(I:C) treatment. Application of Poly(I:C) prompted the transition of HPCs and LSKs from G0 to G1 phases, potentially leading to the accelerated exhaustion of HPCs. From the cobblestone area-forming cell (CAFC) assay, we speculate that Poly(I:C) impairs the differentiation capacity of HPCs as well as their colony-forming ability. RT-qPCR and immunohistochemistry revealed significant upregulation of IFN-I associated genes and proteins following Poly(I:C) treatment. In conclusion, a single dose of Poly(I:C) induced an acute detrimental effect on HPCs within 48 h potentially due to TLR3 engagement. This activation cascaded into a robust IFN-I response emanating from the bone marrow, underscoring the intricate immunological dynamics at play following Poly(I:C) intervention., Competing Interests: Declaration of competing interest The authors declare no competing financial interests., (Copyright © 2024 European Federation of Immunological Societies. Published by Elsevier B.V. All rights reserved.)

Aging-related anemia contributes to frailty syndrome, cognitive decline and early mortality. The study aim was to evaluate inflammaging in relation to anemia as a prognostic indicator in affected older patients. The participants (73.0 ± 7.2 years) were allocated into anemic (n = 47) and non-anemic (n = 66) groups. The hematological variables RBC, MCV, MCH, RDW, iron and ferritin were significantly lower, whereas erythropoietin EPO and transferrin Tf tended toward higher values in the anemic group. Approx. 26% of individuals demonstrated transferrin saturation TfS < 20%, which clearly indicates age-related iron deficiency. The cut-off values for pro-inflammatory cytokine IL-1β, TNFα and hepcidin were 5.3 ng/mL, 97.7 ng/mL and 9.4 ng/mL, respectively. High IL-1β negatively affected Hb concentration (rs = −0.581, p < 0.0001). Relatively high odds ratios were observed for IL-1β (OR = 72.374, 95%Cl 19.688–354.366) and peripheral blood mononuclear cells CD34 (OR = 3.264, 95%Cl 1.263–8.747) and CD38 (OR = 4.398, 95%Cl 1.701–11.906), which together indicates a higher probability of developing anemia. The results endorse the interplay between inflammatory status and iron metabolism and demonstrated a high usefulness of IL-1β in identification of the underlying causes of anemia, while CD34 and CD38 appeared useful in compensatory response assessment and, in the longer term, as part of a comprehensive approach to anemia monitoring in older adults.

The recent development of next-generation sequencing (NGS) technologies has contributed to research into various biological processes. These novel NGS technologies have revealed the involvement of epigenetic memories in trained immunity, which are responses to transient stimulation and result in better responses to secondary challenges. Not only innate system cells, such as macrophages, monocytes, and natural killer cells, but also bone marrow hematopoietic stem cells (HSCs) have been found to gain memories upon transient stimulation, leading to the enhancement of responses to secondary challenges. Various stimuli, including microbial infection, can induce the epigenetic reprogramming of innate immune cells and HSCs, which can result in an augmented response to secondary stimulation. In this review, we introduce novel NGS technologies and their application to unraveling epigenetic memories that are key in trained immunity and summarize the recent findings in trained immunity. We also discuss our most recent finding regarding epigenetic memory in aged HSCs, which may be associated with the exposure of HSCs to aging-related stresses. [ABSTRACT FROM AUTHOR]

To study the environmental radiation effects of wild animals after the Fukushima Dai-ichi nuclear power plant accident, we assessed effects on hematopoietic progenitor cells (HPCs) in large Japanese field mice (Apodemus speciosus). A. speciosus were collected from three contaminated sites and control area. The air dose-rates at the control and contaminated areas were 0.96 ± 0.05 μGy/d (Hirosaki), 14.4 ± 2.4 μGy/d (Tanashio), 208.8 ± 31.2 μGy/d (Ide), 470.4 ± 93.6 μGy/d (Omaru), respectively. We investigated possible DNA damage and pro-inflammatory markers in the bone marrow (BM) cells. The colony-forming potential of BM cells was estimated by the number of HPC colony-forming cells. Radiation-induced genomic instability (RIGI) in HPCs was also analyzed by quantifying delayed DNA damage in CFU-GM clones. Although no significant differences in DNA damage and inflammation markers in BM cells from control and contaminated areas, the number of HPC colonies exhibited an inverse correlation with air dose-rate. With regard to RIGI, no significant differences in DNA damage of CFU-GM clones between the mice from the control and the three contaminated areas. Our study suggests that low dose-rate radiation of more than 200 Gy/d reduced HPCs, possibly eliminating genomically unstable HPCs. [ABSTRACT FROM AUTHOR]

Background. Previously, the antitumor activity of nanocomplexes (NCs) containing nanoparticles of rare earth metal orthovanadates GdYEuVO4 and cholesterol has been approved when applied in 9:1 ratio (the cells-to-NCs), which can be considered as a conditionally therapeutic dose. Therefore, studying the potential risks of NCs exposure in terms of functional activity of hematopoietic progenitor cells is relevant. Рurpose – determining a toxic effect of NCs on functional activity of hematopoietic cells of bone marrow (BM). Materials and Methods. The study was performed in BM cells of CBA/H mice. Nanocomplexes were synthesized at Institute for Scintillation Materials of the National Academy of Sciences of Ukraine. BM cells with NCs were incubated in the ratios as follows: 9BM:1NCs; 1BM:1NCs; 1BM:9NCs, followed by assessing the number of apoptotic/necrotic cells in BM using FITC Annexin V Apoptosis Detection Kit I (BD, USA) by means of “FACS Calibur” flow cytometer (“BD”, USA). Hematopoietic progenitor cells of BM were functionally evaluated in vivo by determining the content of colony-forming units of the spleen (CFUs) and the number of myelokaryocytes in lethally irradiated recipients on day 8 after administering BM cells, pre-incubated with NCs. Survival of irradiated recipient mice after BM administration was recorded 12 days long. Results and discussion. The dose-dependent effect of functional potential in- hibition for BM hematopoietic progenitor cells under NCs influence has been established. Although, in vitro processing the BM cells with a conditionally therapeutic dose of NCs (9BM:1NCs) before administration to irradiated animal caused remodeling of cell membranes and contributed to apoptotic manifes- tations, but it did not lead to strong changes in their colony-forming potential and did not reduce the number of BM cells in animals if compared with the introduced BM cells without NCs treatment. Increasing the NCs concentration five- and tenfold significantly reduced the colony-forming potential of BM cells, caused BM hypoplasia and a crucial reduction in the survival of recipient animals, indicating possible toxic effects of this compound when administered at high concentrations. Conclusions. The toxic effect of NCs is detected only when certain concen- trations, significantly exceeding the conditionally therapeutic dose previously determined when treating the experimental oncology diseases, are used.

Spaceflight affects the body on every level. Reports on astronaut health identify bone marrow remodelling and dysfunction of the innate immune system as significant health risks of long-term habitation in space. Microgravity-induced alterations of the bone marrow induce physical changes to the bone marrow stem cell niche. Downstream effects on innate immunity are expected due to impaired hematopoiesis and myelopoiesis. To date, few studies have investigated these effects in real microgravity and the sparsely available literature often reports contrasting results. This emphasizes a need for the development of physiologically relevant in vitro models of the bone marrow stem cell niche, capable of delivering appropriate sample sizes for robust statistics. Here, we review recent findings on the impact of spaceflight conditions on innate immunity in in vitro and animal models and discusses the latest in vitro models of the bone marrow stem cell niche and their potential translatability to gravitational biology research. [ABSTRACT FROM AUTHOR]

Objective: This study aims to explore the potential of in situ airway differentiation of eosinophil progenitors (EoPs) and hematopoietic progenitor cells (HPCs) in sputum and peripheral blood from patients with non-asthmatic eosinophilic bronchitis (NAEB), eosinophilic asthma (EA), and healthy controls (HC). Methods: Using flow cytometry, we enumerated sputum and blood HPCs and EoPs in patients with NAEB (n=15), EA (n=15), and HC (n=14) at baseline. Patients with NAEB and EA were then treated for 1 month with budesonide (200 μg, bid) or budesonide and formoterol (200/6 μg, bid), respectively. HPCs and EoPs in both compartments were re-evaluated. Results: At baseline, NAEB and EA both had significantly greater numbers of sputum but not blood HPCs and EoPs (p <0.05) compared to HC. There were no differences between NAEB and EA. After 1 month of inhaled corticosteroid (ICS) treatment, NAEB patients showed a significant improvement in cough symptoms, but the attenuation of sputum HPC and EoP levels was not significant. Conclusions: NAEB patients have increased airway levels of HPCs and EoPs. One-month treatment with ICS did not fully suppress the level of EoPs in NAEB. Controlling in situ airway differentiation of EoPs may control airway eosinophilia and provide long-term resolution of symptoms in NAEB. [ABSTRACT FROM AUTHOR]

Hematopoietic stem cell transplantation (HSCT) represents the only curative treatment option for numerous hematologic malignancies. While the influence of donor age and the composition of the graft have already been examined in clinical and preclinical studies, little information is available on the extent to which different hematological subpopulations contribute to the dynamics of the reconstitution process and on whether and how these contributions are altered with age. In a murine model of HSCT, we therefore simultaneously tracked different cultivated and transduced hematopoietic stem and progenitor cell (HSPC) populations using a multicolor-coded barcode system (BC32). We studied a series of age-matched and age-mismatched transplantations and compared the influence of age on the reconstitution dynamics. We show that reconstitution from these cultured and assembled grafts was substantially driven by hematopoietic stem cells (HSCs) and multipotent progenitors (MPPs) independent of age. The reconstitution patterns were polyclonal and stable in all age groups independently of the variability between individual animals, with higher output rates from MPPs than from HSCs. Our experiments suggest that the dynamics of reconstitution and the contribution of cultured and individually transduced HSPC subpopulations are largely independent of age. Our findings support ongoing efforts to expand the application of HSCT in older individuals as a promising strategy to combat hematological diseases, including gene therapy applications. [ABSTRACT FROM AUTHOR]

Diffusion capsules implanted in the abdominal cavity of the mouse recipient are one of the variants of the humanized model of “human-animal” systems. The aim of our study was to determine the optimal parameters for the cultivation of hematopoietic progenitor cells in gel diffusion chambers and their functional activity of bone marrow cells from different locations. To achieve this goal, the method of cultivation in gel diffusion chambers in vivo combined with the method of colony formation in semi-liquid agar, cytological research methods and light microscopy were used. The optimal conditions of cultivation and kinetic indicators of cell aggregate formation by bone marrow precursors of patients without hematological pathology in semi-liquid medium were established in vivo in 16 days of cultivation. We determined that the most suitable term for taking the results of experiments is at 12th day of cultivation. The number of cells that was determined to be optimal for further studies was 5 · 105 cells in 1 ml, or 1 · 105 cells per chamber. Our results suggest that regardless of the place of collection of biological material in humans, the formation of colony in the culture of diffusion chambers is maintained at nearly the same level. The CFU activity for the sternal puncture was 36.5 ± 2.3, the CFU activity for bone marrow from the rib fragment was 38.5 ± 4.8, the CFU activity for trepan biopsy from the anterior upper part of the iliac crest was 35.5 ± 6.8 and the CFU activity from the posterior upper part of the iliac crest was 37.3 ± 5.5. These observations are important for evaluation of functional activity and further use of stem cells from different parts of bone tissue in the case of transplantation. This is further supported by the proliferative potential of colony formation and the index of cell maturation in clones. The obtained data deepen our understanding of the functioning of the hematopoietic stem cells in the human body under normal conditions. [ABSTRACT FROM AUTHOR]

Introduction: Stem cell enumeration by the hematopoietic progenitor cells (HPC) mode is a novel method available from Sysmex XN2000 hematology analyzer. A small amount of blood (190 μL) is required, and the results are available in a few minutes without manual gating or presample treatment. The present study compares stem cell measurements using XN2000 analyzer HPC mode and FC500 flow cytometry analyzer using peripheral blood (PB) specimens and apheresis products. Methods: In this prospective study, CD34‐positive cell counts were enumerated using an FC500 flow cytometry analyzer and compared with XN2000 Sysmex analyzer (XN‐HPC mode) in the same samples. Results were compared using Bland‐Altman plots. Results: A total of 103 samples were used. In the PB samples, the median HPC count and CD34‐positive cells were 83.5 × 106/L and 78.0 × 106/L, respectively. The mean Bland‐Altman difference was 4.5 × 106/L (Limits: −51.7 to 60.7 × 106/L), with a Pearson's correlation of 0.79. In the apheresis products, the median HPC count and CD34‐positive cells were 1468 × 106/L (IQR: 1049 ‐ 1960 × 106/L) and 1327 × 106/L (IQR: 910 ‐ 2001 × 106/L), respectively. The mean Bland‐Altman difference was 179.0 × 106/L (Limits: −2022.2 ‐ 2380.2 × 106/L), with a Pearson's correlation of 0.58. Conclusion: The XN‐HPC mode has an excellent correlation and minimal disagreement for stem cell enumeration in PB compared with flow cytometry and could replace it. There is high disagreement in apheresis products, and therefore, the XN‐HPC mode cannot be recommended. [ABSTRACT FROM AUTHOR]

Abstract Background Human CD133+ hematopoietic progenitor cells (HPCs) are a specific subset of cells that can regulate tumor malignancy. However, the mechanism by which CD133+ HPCs affect the malignancy of human breast cancer has not been reported. Methods CD133+ HPCs were isolated and purified from human umbilical cord blood (UCB). We used in vitro culture of MCF-7 and MDA-MB-231 cell lines, and MCF-7 and MDA-MB-231 cells in nude mice to evaluate whether CD133+ HPCs affected the apoptosis, proliferation, invasion and epithelial mesenchymal transition EMT of breast cancer cells. Results Co-culture with CD133+ HPCs, but not UCB CD133- cells, promoted the proliferation of human breast cancer MCF-7 and MDA-MB-231 cells, accompanied by reducing in vitro spontaneous apoptosis. Co-administration of these two lines with CD133+ HPCs significantly enhanced the growth of implanted breast cancer in vivo. Furthermore, co-culture with CD133+ HPCs, enhanced the invasion of breast cancer cells, N-cadherin and Vimentin expression, but reduced E-cadherin expression in breast cancer cells. Conclusions Our study demonstrated that CD133+ HPCs enhance the malignancy of breast cancer cells by attenuating spontaneous apoptosis and promoting the process of epithelial mesenchymal transition. These findings may provide new insights into the role of human CD133+ HPCs in breast cancer pathogenesis. Therefore, CD133+ HPCs may be a new therapeutic target for inhibiting the progression of breast cancer.

ObjectiveThis study aims to explore the potential of in situ airway differentiation of eosinophil progenitors (EoPs) and hematopoietic progenitor cells (HPCs) in sputum and peripheral blood from patients with non-asthmatic eosinophilic bronchitis (NAEB), eosinophilic asthma (EA), and healthy controls (HC).MethodsUsing flow cytometry, we enumerated sputum and blood HPCs and EoPs in patients with NAEB (n=15), EA (n=15), and HC (n=14) at baseline. Patients with NAEB and EA were then treated for 1 month with budesonide (200 μg, bid) or budesonide and formoterol (200/6 μg, bid), respectively. HPCs and EoPs in both compartments were re-evaluated.ResultsAt baseline, NAEB and EA both had significantly greater numbers of sputum but not blood HPCs and EoPs (p

Objective: determining of the functional activity of mice bone marrow hematopoietic progenitor cells, cultivated in gel diffusion chambers, on the stages of hematopoiesis recovery after their prolonged irradiation in the lethal dose in a comparative aspect with the method of colony forming in spleen using mathematical model. Materials and methods. The method of cell cultivation in gel diffusion chambers, cytological methods, mathematical modeling, and statistical methods of research were used. Bone marrow samples extracted from the femur of mice irradiated with a total dose of 8 Gy with a power 0.0028 Gy/min were cultivated in diffusion chambers with semisolid agar in the abdominal cavity of CBA recipient mice. Results. Comparative analysis of the colony-forming efficiency of progenitor cells (CFU) was carried out during cultivation in gel diffusion chambers in the process of hematopoiesis recovery for 30 days, as well as in the spleen of lethally irradiated animals, in accordance with the mathematical model. Analysis of colony forming kinetics in gel diffusion chambers after prolonged exposure to ionizing radiation indicated the biphasic nature of hematopoiesis recovery. Thus, in the first few days after the irradiation a drop in the number of CFU is observed compared to the control, which continues until the 9th day. Subsequently there is a sharp increase in the number of CFU in cell culture, which continues until the complete recovery of hematopoiesis. The obtained data, recalculated per mouse femur, correspond to the results of colony forming in the spleen of irradiated animals, described by K. S. Chertkov and taken as a basis while developing our mathematical model, as well as to its parameters, which describe the process of hematopoiesis recovery. Conclusions. Conformity of the indices obtained during the cultivation using the method of gel diffusion chambers of mice bone marrow prolongedly irradiated at a total dose of 8 Gy with a power 0.0028 Gy/min, to the results of colony forming in spleen of lethally irradiated mice, which were the basis for mathematical model development, is the evidence of the feasibility of using a mathematical model to assess the process of hematopoiesis recovery by progenitor cells of different maturation levels, and the experimental approach of CFU growing in gel diffusion chambers can be considered as an additional method of researching the hematopoiesis recovery along with the spleen colony method. [ABSTRACT FROM AUTHOR]

Myelodysplastic syndrome is a clonal disease with changes that occur due to mutations that lead to cytogenetic disorders and involve the hematopoietic stem cell. Researchers have shown that colony growth types in leukemic cell culture with acute and chronic myeloid leukaemia are of a prognostic value to determine the likelihood of remission or disease progression. However, there is no single point of view on the prognostic value of clonal culture research methods in MDS. The aim of the study was to determine the role of hematopoietic progenitor cells, the closest descendants of stem cells, in the formation of the pathological process in MDS, and identify the features of colony formation and morphological composition of bone marrow colonies in patients in vitro and in vivo in diffusion chambers implanted in the abdominal cavity of linear animals to determine their possible prognostic value. Bone marrow samples from patients with MDS with an excess of blasts-1 were examined by haematological, cultural, cytological and statistical methods. The features of colony formation in culture with semi-liquid agar of bone marrow of patients with MDS with an excess of blasts-1 were revealed. It has been established that in patients with the disease detection, the colony-forming ability in the semi-liquid agar of progenitor cells is reduced, the number of cells in the colonies decreases, and the appearance of capricious forms of cell aggregates with changes in culture differentiation were detected. The ability of bone marrow in MDS with an excess of blasts-1 to form colony clones by hematopoietic progenitor cells when cultured in semi-liquid agar both in vitro and in vivo was evaluated. Informative indicators of morphofunctional characteristics of stem cells and their descendants in culture, such as colony-forming ability and cell content of colonies, were determined. It is proved that the results of cultivation in diffusion chambers in vivo are comparable with the data obtained in vitro, and can become, along with traditional methods, an additional sign of detection and progression of MDS. [ABSTRACT FROM AUTHOR]

Extensive research has explored the functional correlation between stem cells and progenitor cells, particularly in blood. Hematopoietic stem cells (HSCs) can self-renew and regenerate tissues within the bone marrow, while stromal cells regulate tissue function. Recent studies have validated the role of mammalian stem cells within specific environments, providing initial empirical proof of this functional phenomenon. The interaction between bone and blood has always been vital to the function of the human body. It was initially proposed that during evolution, mammalian stem cells formed a complex relationship with the surrounding microenvironment, known as the niche. Researchers are currently debating the significance of molecular-level data to identify individual stromal cell types due to incomplete stromal cell mapping. Obtaining these data can help determine the specific activities of HSCs in bone marrow. This review summarizes key topics from previous studies on HSCs and their environment, discussing current and developing concepts related to HSCs and their niche in the bone marrow.

Hematopoietic stem cells (HSCs) have been considered to progressively lose their self-renewal and differentiation potentials prior to the commitment to each blood lineage. However, recent studies have suggested that megakaryocyte progenitors (MkPs) are generated at the level of HSCs. In this study, we newly identified early megakaryocyte lineage-committed progenitors (MgPs) mainly in CD201 - CD48 - cells and CD48 + cells separated from the CD150 + CD34 - Kit + Sca-1 + Lin - HSC population of the bone marrow in adult mice. Single-cell colony assay and single-cell transplantation showed that MgPs, unlike platelet-biased HSCs, had little repopulating potential in vivo, but formed larger megakaryocyte colonies in vitro (on average 8 megakaryocytes per colony) than did previously reported MkPs. Single-cell RNA sequencing supported that HSCs give rise to MkPs through MgPs along a Mk differentiation pathway. Single-cell reverse transcription polymerase chain reaction (RT-PCR) analysis showed that MgPs expressed Mk-related genes, but were transcriptionally heterogenous. Clonal culture of HSCs suggested that MgPs are not direct progeny of HSCs. We propose a differentiation model in which HSCs give rise to MgPs which then give rise to MkPs, supporting a classic model in which Mk-lineage commitment takes place at a late stage of differentiation., (Copyright © 2024 The Authors. Published by Wolters Kluwer Health Inc., on behalf of the Chinese Medical Association (CMA) and Institute of Hematology, Chinese Academy of Medical Sciences & Peking Union Medical College (IHCAMS).)

The phenotype of mice carrying the Gata1 low mutation that decreases expression of Gata1 in erythroid cells and megakaryocytes, includes anemia, thrombocytopenia, hematopoietic failure in bone marrow and development of extramedullary hematopoiesis in spleen. With age, these mice develop myelofibrosis, a disease sustained by alterations in stem/progenitor cells and megakaryocytes. This study analyzed the capacity of hGATA1 driven by a μLCR / β-globin promoter to rescue the phenotype induced by the Gata1 low mutation in mice. Double hGATA1 / Gata1 low/0 mice were viable at birth with hematocrits greater than those of their Gata1 low/0 littermates but platelet counts remained lower than normal. hGATA1 mRNA was expressed by progenitor and erythroid cells from double mutant mice but not by megakaryocytes analyzed in parallel. The erythroid cells from hGATA1/Gata1 low/0 mice expressed greater levels of GATA1 protein and of α - and β -globin mRNA than cells from Gata1 low/0 littermates and a reduced number of them was in apoptosis. By contrast, hGATA1/Gata1 low/0 megakaryocytes expressed barely detectable levels of GATA1 and their expression of acetylcholinesterase, Von Willebrand factor and platelet factor 4 as well as their morphology remained altered. In comparison with Gata1 +/0 littermates, Gata1 low/0 mice contained significantly lower total and progenitor cell numbers in bone marrow while the number of these cells in spleen was greater than normal. The presence of hGATA1 greatly increased the total cell number in the bone marrow of Gata1 low/0 mice and, although did not affect the total cell number of the spleen which remained greater than normal, it reduced the frequency of progenitor cells in this organ. The ability of hGATA1 to rescue the hematopoietic functions of the bone marrow of the double mutants was confirmed by the observation that these mice survive well splenectomy and did not develop myelofibrosis with age. These results indicate that hGATA1 under the control of µLCR/β-globin promoter is expressed in adult progenitors and erythroid cells but not in megakaryocytes rescuing the erythroid but not the megakaryocyte defect induced by the Gata1 low/0 mutation. [ABSTRACT FROM AUTHOR]

Derivation of hematopoietic stem cells (HSCs) from human pluripotent stem cells remains a key goal for the fields of developmental biology and regenerative medicine. Here, we use a novel genetic reporter system to prospectively identify and isolate early hematopoietic cells derived from human embryonic stem cells (hESCs) and human induced pluripotent cells (iPSCs). Cloning the human RUNX1c P1 promoter and +24 enhancer to drive expression of tdTomato (tdTom) in hESCs and iPSCs, we demonstrate that tdTom expression faithfully enriches for RUNX1c-expressing hematopoietic progenitor cells. Time-lapse microscopy demonstrated the tdTom(+) hematopoietic cells to emerge from adherent cells. Furthermore, inhibition of primitive hematopoiesis by blocking Activin/Nodal signaling promoted the expansion and/or survival of the tdTom(+) population. Notably, RUNX1c/tdTom(+) cells represent only a limited subpopulation of the CD34(+) CD45(+) and CD34(+) CD43(+) cells with a unique genetic signature. Using gene array analysis, we find significantly lower expression of Let-7 and mir181a microRNAs in the RUNX1c/tdTom(+) cell population. These phenotypic and genetic analyses comparing the RUNX1c/tdTom(+) population to CD34(+) CD45(+) umbilical cord blood and fetal liver demonstrate several key differences that likely impact the development of HSCs capable of long-term multilineage engraftment from hESCs and iPSCs.

The phenotype of mice carrying the Gata1low mutation that decreases expression of Gata1 in erythroid cells and megakaryocytes, includes anemia, thrombocytopenia, hematopoietic failure in bone marrow and development of extramedullary hematopoiesis in spleen. With age, these mice develop myelofibrosis, a disease sustained by alterations in stem/progenitor cells and megakaryocytes. This study analyzed the capacity of hGATA1 driven by a μLCR/β-globin promoter to rescue the phenotype induced by the Gata1low mutation in mice. Double hGATA1/Gata1low/0 mice were viable at birth with hematocrits greater than those of their Gata1low/0 littermates but platelet counts remained lower than normal. hGATA1 mRNA was expressed by progenitor and erythroid cells from double mutant mice but not by megakaryocytes analyzed in parallel. The erythroid cells from hGATA1/Gata1low/0 mice expressed greater levels of GATA1 protein and of α- and β-globin mRNA than cells from Gata1low/0 littermates and a reduced number of them was in apoptosis. By contrast, hGATA1/Gata1low/0 megakaryocytes expressed barely detectable levels of GATA1 and their expression of acetylcholinesterase, Von Willebrand factor and platelet factor 4 as well as their morphology remained altered. In comparison with Gata1+/0 littermates, Gata1low/0 mice contained significantly lower total and progenitor cell numbers in bone marrow while the number of these cells in spleen was greater than normal. The presence of hGATA1 greatly increased the total cell number in the bone marrow of Gata1low/0 mice and, although did not affect the total cell number of the spleen which remained greater than normal, it reduced the frequency of progenitor cells in this organ. The ability of hGATA1 to rescue the hematopoietic functions of the bone marrow of the double mutants was confirmed by the observation that these mice survive well splenectomy and did not develop myelofibrosis with age. These results indicate that hGATA1 under the control of µLCR/β-globin promoter is expressed in adult progenitors and erythroid cells but not in megakaryocytes rescuing the erythroid but not the megakaryocyte defect induced by the Gata1low/0 mutation.

The localization and quantification of endothelial progenitor cells (EPCs) are controversial. Circulating CD34 + cells in blood have been identified as EPCs and as biomarkers of cardiovascular disease. We discuss in this paper the current data describing differential phenotype and behavior in vitro of CD34 positive cells from the circulation and adipose tissue (AT). We also describe in brief our own findings from CD34 + cells isolated from leukopheresis cones derived from healthy platelet donors and from patients undergoing bariatric surgery. We conclude that CD34 + cells in blood and in AT are different in antigenic profile and behavior in culture. The findings described assert that CD34 + cells detected in blood previously identified as biomarkers of cardiovascular disease are predominantly HPCs rather than EPCs, and that true CD34 + EPCs can be readily identified and extracted from AT, supportive of the current evidence which suggests EPCs are resident in the tissue vasculature.

Hematopoietic stem cells (HSCs) in bone marrow continuously supply a large number of blood cells throughout life in collaboration with hematopoietic progenitor cells (HPCs). HSCs and HPCs are thought to regulate and utilize intracellular metabolic programs to obtain metabolites, such as adenosine triphosphate (ATP), which is necessary for various cellular functions. Metabolites not only provide stem/progenitor cells with nutrients for ATP and building block generation but are also utilized for protein modification and epigenetic regulation to maintain cellular characteristics. In recent years, the metabolic programs of tissue stem/progenitor cells and their underlying molecular mechanisms have been elucidated using a variety of metabolic analysis methods. In this review, we first present the advantages and disadvantages of the current approaches applicable to the metabolic analysis of tissue stem/progenitor cells, including HSCs and HPCs. In the second half, we discuss the characteristics and regulatory mechanisms of HSC metabolism, including the decoupling of ATP production by glycolysis and mitochondria. These technologies and findings have the potential to advance stem cell biology and engineering from a metabolic perspective and to establish therapeutic approaches.