Bone marrow microenvironment is the environment in which hematopoietic stem cells live, mainly composed of bone marrow stromal cells, microvessels, nerves, and cytokines secreted by stromal cells. The bone marrow microenvironment plays a crucial role in the self-renewal, directed differentiation and proliferation of hematopoietic stem cells and the regulation of proliferation, differentiation and maturation of hematopoietic cells. A class of macrophages exists in the bone marrow microenvironment, the bone marrow-resident tissue macrophages, which plays a crucial role in maintaining homeostasis in vivo, and three subpopulations of bone marrow-resident tissue macrophages have been characterized: erythroblastic island macrophages (EIMs), hematopoietic stem cell niche macrophages, and bone macrophages. This review focuses on the functions, surface markers and modeling of EIMs.
Macrophages/cytology* ; Humans ; Erythroblasts/cytology* ; Animals ; Hematopoietic Stem Cells/cytology*

OBJECTIVE: To analyze the effect of COVID-19 infection on the mobilization and collection of autologous peripheral blood stem cells in patients with multiple myeloma. METHODS: The general baseline data, treatment factors before mobilization collection, collection status, and treatment overview after collection of autologous peripheral blood stem cells at Beijing Chaoyang Hospital affiliated with Capital Medical University from January 1, 2020 to July 15, 2023 were analyzed. RESULTS: 269 patients underwent mobilization and collection of autologous peripheral blood stem cells. Among them, 32 cases with COVID-19 infection history (COVID-19 group) and 237 cases without COVID-19 infection history (non-COVID-19 group). In the COVID-19 group, 17 cases were treated with chemotherapy (etoposide)+G-CSF, and 15 cases were treated with plerixafor +G-CSF. In the non-COVID-19 group, 214 cases were treated with chemotherapy +G-CSF, 17 cases were treated with plerixafor +G-CSF, and 6 cases were treated with chemotherapy + plerixafor +G-CSF. The number of CD34⁺ cells, collection success rate, and excellence rate in the COVID-19 group and the non-COVID-19 group were ［5.52 (0.94-26.87) vs 4.80 (0.53-37.20)］×10⁶/kg (P =0.610), (93.8% vs 85.2%) (P =0.275), (62.5% vs 49.4%) (P =0.190), respectively. Among 113 patients mobilized with etoposide +G-CSF, the number of CD34⁺ cells, success rate, and excellence rate collected from COVID-19 infection (17 cases) and non-COVID-19 infection (96 cases) were ［7.54 (2.66-26.87) vs 7.78 (2.26-37.20)］×10⁶/kg (P =0.847), (100.0% vs 100.0%) (no P value), (82.4% vs 86.5%) (P =0.655), respectively. Among 32 patients mobilized by plerixafor +G-CSF, the number of CD34⁺ cells, success rate and excellence rate of COVID-19 infection (15 cases) and non-COVID-19 infection (17 cases) were ［3.82 (0.94-7.27) vs 4.11 (0.53-9.05)］×10⁶/kg (P =0.821), (86.7% vs 88.2%) (P =0.893), (40.0% vs 35.3%) (P =0.784), respectively. In 32 patients with COVID-19 infection, the number of CD34⁺ cells collected by etoposide +G-CSF (17 cases) and plerixafor +G-CSF (15 cases), as well as the success rate and excellence rate were ［7.54 (2.66-26.87) vs 3.82(0.94-7.27)］×10⁶/kg (P =0.004), (100.0% vs 86.7%) (P =0.120), (82.4% vs 40.0%) (P =0.014), respectively. By 2023.7.31, 232 patients (86.2%, 232/269) had received transplantation, including 24 patients in the COVID-19 group and 208 patients in the non-COVID-19 group. The median number of CD34⁺ cells infused in the two groups was ［3.67 (2.50-13.44) vs 3.11(1.12-19.89)］×10⁶/kg (P =0.058), the median days of neutrophil engraftment ［11(9-13) vs 11(9-17)］ (P =0.674), the median days of platelet engraftment ［11(0-23), 12(0-43)］ (P =0.279), respectively. CONCLUSION The history of COVID-19 infection did not affect the PBSC mobilization, collection and transplantation of patients with myeloma. In patients with COVID-19 infection, the results of chemotherapy mobilization with etoposide seems to be better than that of plerixafor mobilization, but further research is needed to clarify.
Humans ; COVID-19/complications* ; Multiple Myeloma/complications* ; Hematopoietic Stem Cell Mobilization ; Transplantation, Autologous ; Granulocyte Colony-Stimulating Factor/therapeutic use* ; Peripheral Blood Stem Cell Transplantation ; SARS-CoV-2 ; Middle Aged ; Peripheral Blood Stem Cells ; Male ; Female ; Cyclams ; Benzylamines

Excessive generation of reactive oxygen species (ROS) can lead to oxidative-antioxidative imbalance in the organism, resulting in oxidative stress. Hematopoietic stem/progenitor cells (HSPCs) exhibit high sensitivity to changes in ROS levels, and high levels of ROS can impair self-renewal capacity of HSPCs, leading to oxidative damage and even death. Wnt/β-catenin signaling pathway regulates hematopoiesis and plays an important role in determining the fate of stem cells, such as self-renewal, proliferation and differentiation of HSPCs. Studies have shown that Wnt/β-catenin signaling pathway is also closely related to oxidative stress. This article summarizes the relevant literature, and reviews the role of Wnt/β-catenin signaling pathway in oxidative stress, its impact on hematopoietic system, and the current research status of related mechanisms.
Oxidative Stress ; Humans ; Wnt Signaling Pathway ; Hematopoietic Stem Cells ; Reactive Oxygen Species/metabolism* ; Hematopoietic System/metabolism* ; beta Catenin/metabolism* ; Hematopoiesis

OBJECTIVE: To investigate the correlation between the types and quantities of immune cells in the graft and early immune reconstitution after allogeneic hematopoietic stem cell transplantation (allo-HSCT) and their influence on clinical prognosis. METHODS: The clinical data of 83 patients with hematological diseases who received allo-HSCT in Shanxi Bethune Hospital from September 2020 to June 2023 were retrospectively analyzed. The number of mononuclear cells (MNC), CD34⁺ cells and lymphocyte subsets (including CD3⁺T, CD3⁺CD4⁺T(Th), CD3⁺CD8⁺T(Ts), NK cells and B cells) infused into the recipients was counted, and the peripheral blood lymphocytes were detected before conditioning and on days 14, 30, 60 and 100 post-HSCT. RESULTS: Multivariate analysis showed that the number of MNC in the graft affected the recovery of CD4⁺T lymphocytes after HSCT, and the number of CD4⁺T lymphocytes in the graft affected the recovery of NK cells and B cells after HSCT. The patient age, donor sex, stem cell source, degree of HLA matching, use of ATG before HSCT, the occurrence of acute graft-versus-host disease (aGVHD) after HSCT, and viral infection all affect the early cellular immune reconstitution post-HSCT. The number of infused cells had no significant impact on the median engraftment time for neutrophils and platelets after HSCT. Patients with lower numbers of CD3⁺T, CD4⁺T and B cells in the graft were more prone to viral infection after HSCT. However, the cells in the graft had no significant effect on disease recurrence or mortality. CONCLUSION The recovery rate of lymphocyte count after allo-HSCT varies. The numbers of MNC and CD4⁺T cells in the graft may be related to the cellular immune reconstitution after HSCT, while the numbers of CD34⁺,CD3⁺T,CD8⁺T,NK and B cells have no significant effect on the cellular immune reconstruction. The numbers of CD3⁺T,CD4⁺T and B cells in the graft were negatively correlated with viral infection after HSCT, but the cellular components of the graft have no obvious influence on hematopoietic reconstitution, disease recurrence, death, recurrence-free survival(RFS) and overall survival(OS) after HSCT.
Humans ; Hematopoietic Stem Cell Transplantation ; Immune Reconstitution ; Transplantation, Homologous ; Retrospective Studies ; Graft vs Host Disease/immunology* ; Male ; Female ; Killer Cells, Natural/immunology* ; Adult ; Middle Aged ; B-Lymphocytes/immunology* ; Prognosis ; Lymphocyte Subsets/immunology* ; Adolescent

OBJECTIVE: To investigate the effect of irradiation dose rate of ⁶⁰Co γ-ray on hematopoietic and immune cells in total body irradiation (TBI) mice. METHODS: After TBI with 8 Gy ⁶⁰Co γ-ray at three irradiation dose rates of 0.027, 0.256 and 0.597 Gy/min, the survival and change of body weight of C57BL/6J mice were observed within 30 days. The peripheral blood parameters were examined at each time point within 30 days post-irradiation. The hematopoietic stem/progenitor cell counts of mice were examined on the 10^th and 30^th day post-irradiation by flow cytometry, as well as the proportions of immune cells in peripheral blood, bone marrow and spleen of mice on the 30^th day post-irradiation. RESULTS: After TBI with 8 Gy ⁶⁰Co γ-ray, the 30-day survival rate of high dose-rate group was 0, which was significantly lower than 90% of medium dose-rate group and 100% of low dose-rate group (both P < 0.001). The peripheral blood parameters of all three groups showed a sharp decline → low value → gradually recovering trend. The count of white blood cell, neutrophil, lymphocyte, red blood cell, platelet and hemoglobin level in the high dose-rate and medium dose-rate groups were significantly lower than those in the low dose-rate group on day 7-18 post-irradiation (all P < 0.05), but there were no significant differences between the high dose-rate and medium dose-rate groups (P >0.05). On the 10^th day after irradiation, the proportion and number of bone marrow hematopoietic stem/progenitor cells (including LK, LSK, LT-HSC, ST-HSC, and MPP cells) in the low dose-rate and medium dose-rate groups were significantly decreased compared to those in the normal group (all P < 0.05), but there were no significant differences between the two groups (P >0.05). On the 30^th day after irradiation, LSK, LT-HSC, ST-HSC and MPP cells in the low dose-rate group recovered to normal levels, while those in the medium dose-rate group were still significantly lower than those in the low dose-rate group (all P < 0.001). The results of bone marrow and peripheral immune cell tests on the 30^th day after irradiation showed that the ratios of T and B lymphocytes in the low dose-rate and medium dose-rate groups were reduced compared to that in the normal group (both P < 0.05), while the ratio of neutrophils was increased (P < 0.01). The trend of changes in the spleen and peripheral blood was consistent. CONCLUSION The degree of hematopoietic and immune cell damage in mice after TBI with 8 Gy ⁶⁰Co γ-ray is related to the dose rate, and low dose-rate irradiation can reduce the damage in the animal model. Therefore, choosing the appropriate dose rate of irradiation is a key factor in establishing an objective and reliable experimental animal model of irradiation.
Animals ; Mice ; Whole-Body Irradiation ; Gamma Rays ; Mice, Inbred C57BL ; Hematopoietic Stem Cells/radiation effects* ; Cobalt Radioisotopes ; Dose-Response Relationship, Radiation ; Male

OBJECTIVE: To explore the safety and efficacy of high-dose etoposide (VP-16) combined with recombinant human granulocyte colony-stimulating factor (rhG-CSF) as salvage mobilization for peripheral blood stem cells (PBSC) in newly diagnosed multiple myeloma (NDMM) patients. METHODS: From April 2021 to May 2023, eight NDMM patients who had failed to yield sufficient PBSC during initial mobilization with high-dose cyclophosphamide (CTX) combined with rhG-CSF underwent salvage mobilization with 1.2 g/m2 etoposide combined with rhG-CSF 10 μg/(kg·d). The effects and adverse reactions of initial mobilization and salvage mobilization were analyzed. RESULTS: For salvage mobilization and initial mobilization, the numbers of PBSC collections were 16 and 18, respectively. The mean value of total collected CD34⁺ cells were (11.90±5.75)×10⁶/kg and (1.67±0.75)×10⁶/kg (P =0.0010) in salvage mobilization group and initial mobilization group, respectively. The proportion of patients with a total collection of CD34⁺ cell count≥2×10⁶/kg were 100% and 37.5% (P =0.0625), and the proportion of patients with a total collection of CD34⁺ cell count≥5×10⁶/kg were 87.5% and 0% (P =0.0156) in salvage mobilization group and initial mobilization group, respectively. For five patients who underwent high-dose CTX initial mobilization but had a total CD34⁺ cell count < 2×10⁶/kg, successful collection was achieved through salvage mobilization with high-dose VP-16. Salvage mobilization with high-dose VP-16 was scheduled 2-3 weeks after failure of CTX mobilization. Adverse reactions of high-dose VP-16 mobilization did not increase compared to the initial mobilization with high-dose CTX. CONCLUSION As a salvage mobilization regimen, VP-16 1.2 g/m² combined with rhG-CSF is safe and highly effective in NDMM patients who failed to initial mobilization with high-dose CTX combined with rhG-CSF.
Humans ; Multiple Myeloma/therapy* ; Etoposide/therapeutic use* ; Hematopoietic Stem Cell Mobilization/methods* ; Cyclophosphamide/therapeutic use* ; Granulocyte Colony-Stimulating Factor ; Salvage Therapy ; Peripheral Blood Stem Cells ; Male ; Middle Aged ; Female ; Peripheral Blood Stem Cell Transplantation

OBJECTIVE: To analyze the Epstein-Barr virus (EBV) load in different lymphocyte subsets, as well as clinical characteristics and outcomes in patients with hematologic malignancies experiencing EBV reactivation. METHODS: Peripheral blood samples from patients were collected. B, T, and NK cells were isolated sorting with magnetic beads by flow cytometry. The EBV load in each subset was quantitated by real-time quantitative polymerase chain reaction (RT-qPCR). Clinical data were colleted from electronic medical records. Survival status was followed up through outpatient visits and telephone calls. Statistical analyses were performed using SPSS 25.0. RESULTS: A total of 39 patients with hematologic malignancies were included, among whom 35 patients had undergone allogeneic hematopoietic stem cell transplantation (allo-HSCT). The median time to EBV reactivation was 4.8 months (range: 1.7-57.1 months) after allo-HSCT. EBV was detected in B, T, and NK cells in 20 patients, in B and T cells in 11 patients, and only in B cells in 4 patients. In the 35 patients, the median EBV load in B cells was 2.19×10⁴ copies/ml, significantly higher than that in T cells (4.00×10³ copies/ml, P <0.01) and NK cells (2.85×10² copies/ml, P <0.01). Rituximab (RTX) was administered for 32 patients, resulting in EBV negativity in 32 patients with a median time of 8 days (range: 2-39 days). Post-treatment analysis of 13 patients showed EBV were all negative in B, T, and NK cells. In the four non-transplant patients, the median time to EBV reactivation was 35 days (range: 1-328 days) after diagnosis of the primary disease. EBV was detected in one or two subsets of B, T, or NK cells, but not simultaneously in all three subsets. These patients received a combination chemotherapy targeting at the primary disease, with 3 patients achieving EBV negativity, and the median time to be negative was 40 days (range: 13-75 days). CONCLUSION In hematologic malignancy patients after allo-HSCT, EBV reactivation commonly involves B, T, and NK cells, with a significantly higher viral load in B cells compared to T and NK cells. Rituximab is effective for EBV clearance. In non-transplant patients, EBV reactivation is restricted to one or two lymphocyte subsets, and clearance is slower, highlighting the need for prompt anti-tumor therapy.
Humans ; Hematologic Neoplasms/virology* ; Herpesvirus 4, Human/physiology* ; Epstein-Barr Virus Infections ; Hematopoietic Stem Cell Transplantation ; Virus Activation ; Lymphocyte Subsets/virology* ; Flow Cytometry ; Killer Cells, Natural/virology* ; Male ; Female ; B-Lymphocytes/virology* ; Viral Load ; Adult ; T-Lymphocytes/virology* ; Middle Aged

OBJECTIVE: To investigate the regulatory effect of Wip1 phosphatase on hematopoietic function in the mouse spleen. METHODS: Wip1 knockout mice were bred, and the effect of Wip1 deletion on the proportion and number of hematopoietic stem/progenitor cells, as well as their mature subsets in mouse spleen was detected by flow cytometry. The Proteome Profiler^TM antibody array was used to analyze the role of Wip1 deletion on the expression of inflammatory cytokines in CD45^highCD11b⁺ myeloid cells sorted from mouse spleen. RESULTS: Wip1 deletion resulted in smaller size and significant reduction of cell number in the mouse spleen. The absolute numbers of hematopoietic stem/progenitor cells were decreased. Meanwhile, the absolute number of T and B lymphocytes also significantly declined. However, the proportion of erythroid progenitors and erythroid cells at various stage significantly increased, but the number of mature erythroid cells decreased. Furthermore, the myeloid cells and their subsets neutrophils, monocytes, CD45^highCD11b⁺ and CD45^lowCD11b⁺ were all reduced. CD45^highCD11b⁺ myeloid cells displayed proinflammatory phenotype in the spleen. CONCLUSION Wip1 gene deletion impairs normal hematopoietic function in the mouse spleen, leading to a significant reduction of mature hematopoietic cells of various lineages, and proinflammatory phenotype in CD45^highCD11b⁺ myeloid cells.
Animals ; Mice ; Spleen/cytology* ; Mice, Knockout ; Hematopoietic Stem Cells/cytology* ; Myeloid Cells/cytology* ; Protein Phosphatase 2C ; Hematopoiesis ; Flow Cytometry

OBJECTIVE: To investigate the role of extracellular vesicles (EVs) derived from placental tissue and placental mesenchymal stem cells in supporting the growth and function of adult hematopoietic stem and progenitor cells (HSPCs), so as to optimize their culture system. METHODS: EVs were isolated from mouse placental tissue (PL-EV) and placental mesenchymal stem cells (PL-MSC-EV). These EVs were co-cultured with 3 000 adult bone marrow LKS⁺ (lineage^- c-Kit⁺ Sca-1⁺ ) cells for 72 hours at concentrations of 0, 1, 10, 50, 100, and 200 μg/ml. The proportion and absolute count of LKS⁺ cells after co-culture were analyzed by flow cytometry, while their self-renewal and multi-lineage differentiation potential were evaluated using colony-forming unit (CFU) assays. RESULTS: Compared to the blank control group, the proportion of LKS⁺ cells were significantly increased in PL-EV groups at concentrations ≥10 μg/ml after 72 hours of co-culture. Notably, LKS⁺ cells co-cultured at the concentration of 10 μg/ml exhibited the highest absolute count (899±171) and the highest proportion of LT-HSCs (LKS⁺ CD135^- CD34^-) (0.67%±0.07%). In the PL-MSC-EV co-culture system, the absolute count of LKS⁺ cells peaked at the concentration of 1 μg/ml (1011±99 cells), though the proportion of LT-HSCs was relatively low (0.15%±0.05%). The comparison between these two culture systems revealed that PL-EV at 10 μg/ml and PL-MSC-EV at 1 μg/ml displayed the most pronounced effects on LKS⁺ cell proliferation, but with no significant difference between them. CFU assays showed that, in the PL-EV culture system, the number of LKS⁺ colony formed in 1 and 10 μg/ml groups was not significantly different compared with the blank control group. In contrast, in the PL-MSC-EV system, the highest LKS⁺ colony-forming capacity was observed when co-cultured with 1 μg/ml PL-MSC-EV, while a significant reduction was noted at concentrations above 10 μg/ml. CONCLUSION PL-EV and PL-MSC-EV effectively support the growth and function of HSPCs. And PL-MSC-EV exhibits a superior efficacy in preserving the stemness of LKS⁺ cells, thus suggesting its potential for optimizing culture systems of HSPCs.
Mesenchymal Stem Cells/cytology* ; Extracellular Vesicles ; Placenta/cytology* ; Female ; Animals ; Mice ; Pregnancy ; Hematopoietic Stem Cells/cytology* ; Coculture Techniques ; Cell Differentiation ; Cell Proliferation ; Cells, Cultured

In recent years, with the development of single-cell sequencing technology, spatial transcriptome technology and in vivo tracing technology, scientists have a deeper understanding of scientific issues about the in vivo development, functional regulation and ex vivo expansion of hematopoietic stem cells (HSCs). Among them, epigenetic modification plays an important role in the development and fate decisions, function maintenance and ex vivo expansion of HSCs, which has become a research hotspot in the field of stem cells in recent years. This article reviews the recent research progress of epigenetic modification in the development, functional regulation and expansion of HSCs.
Hematopoietic Stem Cells ; Epigenesis, Genetic ; Humans ; DNA Methylation