Overview of Hematopoietic Stem Cells in Systemic Cancer Treatment, Aging, Pregnancy, and Radiation Hormesis

Background: The unavoidable links between the benefits of conventional systemic treatment of cancer and the side effects such as lymphopenia. Objective: To analyze this phenomenon in view of the newly discovered trophic function of circulating hematopoietic stem cells (HSC) and their lymphocyte descendants. Method: We used population statistics and recent current research involving natural aging and preliminary aging with cancer, its cytotoxic therapy, eclampsia at pregnancy, and radiation hormesis. Results: In contrast to immune-defense interpretations of these health conditions, the trophic influence of HSC and morphogenic lymphocytes on natural tissue renewal and regeneration after sublethal injuries eliminates the majority of covered inconsistencies, which are inherent to the dominating idea of cellular immunity. Conclusion: Our examination led to the feeding influence of lymphopoiesis on tumor progression, an indirect mechanism of tumor growth control by systemic therapy via either destruction of trophic cells, or by competitive distraction from malignant tissue via reparation of sublethal injuries in normal tissues. Analyses also involved similarities of the mechanisms of systemic chemotherapy and total body/half body radiotherapy in low doses, as well as the futility of the theoretical opposition of the radiation hormesis phenomenon to the linear non-threshold model, dominant in radiobiology.

Lead Induced Disorders in Hematopoietic and DrugMetabolizing Enzyme System and Their Protection by Ascorbic Acid Supplementation

Effect of vitamin C supplementation in restoring lead induced alterations in hematopoietic system and drug metabolizing enzymes were investigated in male rats. Intraperitoneal administration of 20 mg/kg lead produced a significant inhibition of heme synthesis in blood and liver and drug metabolism in liver. Toxic insult by lead also resulted into a marked decline in tissue thiols and vitamin C levels. Oral supplementation of vitamin C (100 mg/kg for 3 days) completely restored blood delta aminolevulinic acid dehydratase, uroporphyrinogen I synthetase and a few drug metabolizing enzymes. Level of vitamin C and sulfhydryl contents too recovered to a great extent. A marked reduction in blood and liver lead concentration occurred on vitamin C supplementation although renal lead contents were marginally reduced in lead exposed animals. The results, thus, indicate a significant protective action of vitamin C against toxic effects of lead on heme synthesis and drug metabolism.

Remission is not maintained over 2 years with hematopoietic stem cell transplantation for rheumatoid arthritis:A systematic review with meta-analysis

BACKGROUND Hematopoietic stem cell(HSC)transplantation(HSCT)is being accepted as a standard of care in various inflammatory diseases.The treatment of rheumatoid arthritis(RA)has been closely evolving with the understanding of disease pathogenesis.With the rising resistance to the traditional disease-modifying antirheumatic drugs and targeted biological therapy,researchers are in pursuit of other methods for disease management.Since the ultimate goal of the ideal treatment of RA is to restore immune tolerance,HSCT attracts much attention considering its reparative,paracrine,and anti-inflammatory effects.However,a systematic review of studies on HSCT in RA is lacking.AIM To investigate the role of HSCT in the management of RA.METHODS A detailed search of PubMed,Scopus,EMBASE,Cochrane,and the Web of Science databases was made to identify the relevant articles till September 2020 following Cochrane and PRISMA guidelines.We extracted data including the number of patients,source of hematopoietic stem cells,their mobilization and conditioning regimens,results,and complications from the eligible studies.Results were dichotomized into success(ACR 50/70)and failure(ACR 20)based on the improvement from baseline characteristics.The methodological quality of the included studies was also assessed.Analysis was performed using OpenMeta[Analysis]software.RESULTS We included 17 studies(1 randomized controlled trial,11 prospective,and 5 retrospective studies)with 233 patients for analysis.HSCT provided a significantly beneficial overall improvement in the clinical grades of ACR criteria(Z=11.309,P<0.001).However,the remission was noted only till 24 mo and later on the significance of the result was lost(Z=1.737,P=0.082).A less than 1%treatmentrelated mortality was noted from the included studies.No major drug-related toxicities were noted in any of the included studies.All patients who underwent allogeneic HSCT received immunosuppression in the conditioning regimen to counteract the graft-vs-host reaction which made them vulnerable to infections.It is noted that the source of hematopoietic stem cells did not play a role in altering the functional outcome and both autologous(Z=9.972,P<0.001)and allogenic(Z=6.978,P<0.001)sources produced significant improvement in the outcome compared to the pre-operative state despite having a significant heterogeneity among the studies reporting them(I2=99.4,P<0.001).CONCLUSION Although the available literature is encouraging towards the use of HSCT in refractory cases with significant improvement from baseline till 2 years,the inclusion of HSCT into the standard of care of RA needs further exploration.

Quality-adjusted time without symptoms or toxicity analysis of haploidentical-related donor vs.identical sibling donor hematopoietic stem cell transplantation in acute myeloid leukemia

Objective:We aimed to compare the quality-adjusted time without symptoms or toxicity(Q-TWiST)in acute myeloid leukemia(AML)patients who received haploidentical-related donor(HID)and identical sibling donor(ISD)hematopoietic stem cell transplantation(HSCT).Methods:Five clinical health states were defined:toxicity(TOX),acute graft-versus-host disease(GVHD),chronic GVHD(cGVHD),time without symptoms and toxicity(TWiST)and relapse(REL).The equation used in this study was as follows:Q-TWiST=UTOX×TOX+UTWiST×TWiST+UREL×REL+UaGVHD×aGVHD+UcGVHD×cGVHD.Results:A total of 239 AML patients were enrolled.We established a mathematical model,i.e.,Q-TWiST HID HSCT>Q-TWiST ISD HSCT,to explore the range of utility coefficients satisfying the inequality.Based on the raw data,the utility coefficient is equivalent to the following inequality:10.57067UTOX-46.27733UREL+105.9374+3.388078UaGVHD-210.8198UcGVHD>0.The model showed that when UTOX,UREL,and UaGVHD were within the range of 0-1,as well as when UcGVHD was within the range of 0-0.569,the inequality Q-TWiST HID HSCT>Q-TWiST ISD HSCT was valid.According to the results of the ChiCTR1800016972 study,the median coefficients of TOX,acute GVHD(aGVHD),and cGVHD were 0.56(0.41-0.76),0.56(0.47-0.72),and 0.54(0.37-0.79),respectively.We selected a series of specific examples of the coefficients,i.e.,UTOX=0.5,UREL=0.05,UaGVHD-0.5,and UcGVHD-0.5.The Q-TWiST values of ISD and HID HSCT were 896 and 900 d,respectively(P=0.470).Conclusions:We first observed that Q-TWiST was comparable between AML patients receiving HID HSCT and those receiving ISD HSCT.

Effects of different concentrations of nicotinamide on hematopoietic stem cells cultured in vitro

BACKGROUND In vitro expansion to increase numbers of hematopoietic stem cells(HSCs)in cord blood could improve clinical efficacy of this vital resource.Nicotinamide(NAM)can promote HSC expansion ex vivo,but its effect on hematopoietic stem and progenitor cells(HSPCs,CD34^(+)CD38)and functional subtypes of HSCs-shortterm repopulating HSCs(ST-HSCs,CD34^(+)CD38CD45RACD49f^(+))and long-term repopulating HSCs(LT-HSCs,CD34^(+)CD38CD45RACD49f^(+)CD90^(+))is not yet known.As a sirtuin 1(SIRT1)inhibitor,NAM participates in regulating cell adhesion,polarity,migration,proliferation,and differentiation.However,SIRT1 exhibits dual effects by promoting or inhibiting differentiation in different tissues or cells.We propose that the concentration of NAM may influence proliferation,differentiation,and SIRT1 signaling of HSCs.AIM To evaluate the effects and underlying mechanisms of action of different concentrations of NAM on HSC proliferation and differentiation.METHODS CD34^(+)cells were purified from umbilical cord blood using MacsCD34 beads,and cultured for 10-12 d in a serum-free medium supplemented with cytokines,with different concentrations of NAM added according to experimental requirements.Flow cytometry was used to detect phenotype,cell cycle distribution,and apoptosis of the cultured cells.Real-time polymerase chain reaction was used to detect the transcription levels of target genes encoding stemness-related factors,che mokines,components of hypoxia pathways,and antioxidant enzymes.Dichloro-dihydro-fluorescein diacetate probes were used to evaluate intracellular production of reactive oxygen species(ROS).Determination of the effect of different culture conditions on the balance of cytokine by cytometric bead array.RESULTS Compared with the control group,the proportion and expansion folds of HSPCs(CD34^(+)CD38)incubated with 5 mmol/L or 10 mmol/L NAM were significantly increased(all P<0.05).The ST-HSCs ratio and fold expansion of the 5 mmol/L NAM group were significantly higher than those of the control and 10 mmol/L NAM groups(all P<0.001),whereas the LT-HSCs ratio and fold expansion of the 10 mmol/L NAM group were significantly higher than those of the other two groups(all P<0.05).When the NAM concentration was>10 mmol/L,cell viability significantly decreased.In addition,compared with the 5 mmol/L NAM group,the proportion of apoptotic cells in the 10 mmol/L NAM group increased and the proportion of cells in S and G2 phase decreased.Compared with the 5 mmol/L NAM group,the HSCs incubated with 10 mmol/L NAM exhibited significantly inhibited SIRT1 expression,increased intracellular ROS content,and downregulated expression of genes encoding antioxidant enzymes(superoxide dismutase 1,peroxiredoxin 1).CONCLUSION Low concentrations(5 mmol/L)of NAM can better regulate the balance between proliferation and differentiation,thereby promoting expansion of HSCs.These findings allow adjustment of NAM concentrations according to expansion needs.

Exploring hematopoietic stem cell population in human milk and its benefits for infants:A scoping review

Objective:To comprehensively explore hematopoietic stem cells(HSCs)in human milk,understanding their molecular markers,isolation methods,benefits for infants,and potential medical applications.Methods:We conducted a scoping literature review following the PRISMA-ScR guidelines.This review included studies investigating HSCs in human milk,utilizing molecular markers such as CD34^(+),CD113^(+),and CD117^(+)for characterization.Both in vitro and in vivo studies exploring the morphology,function,and clinical implications of these cells were considered.The diverse range of papers reviewed were indexed in PubMed,Science Direct,Scopus,Sage Journals,and Google Scholar,published between 2010 and 2023.Results:This scoping review explored 577 articles and selected 13 studies based on our inclusion criteria,focusing on HSCs in human milk.Most studies dilute samples prior to HSC isolation,followed by detection using markers such as CD34^(+),CD113^(+),and CD117^(+),with flow cytometry serving as the primary analysis tool,focusing on their isolation and detection methods.While no definitive benefits have been conclusively established,there is a strong belief in the potential of HSCs to positively impact infant immunity,growth,and tissue repair.Conclusions:This review presents significant evidence supporting the presence of HSCs in human milk,identified by markers such as CD34^(+),CD113^(+),and CD117^(+).These cells show considerable potential in enhancing infant health,including immunity,tissue repair,cognitive development,and gastrointestinal health.Despite methodological variations in isolation and detection techniques,the collective findings underscore the potential clinical relevance of HSCs in human milk.Moreover,this review highlights the noninvasive accessibility of human milk as a source of HSCs and emphasizes the need for further research to unlock their therapeutic potential.

Effect of ginsenoside Rg1 on hematopoietic stem cells in treating aplastic anemia in mice via MAPK pathway

BACKGROUND Aplastic anemia(AA)presents a significant clinical challenge as a life-threatening condition due to failure to produce essential blood cells,with the current the-rapeutic options being notably limited.AIM To assess the therapeutic potential of ginsenoside Rg1 on AA,specifically its protective effects,while elucidating the mechanism at play.METHODS We employed a model of myelosuppression induced by cyclophosphamide(CTX)in C57 mice,followed by administration of ginsenoside Rg1 over 13 d.The invest-igation included examining the bone marrow,thymus and spleen for pathological changes via hematoxylin-eosin staining.Moreover,orbital blood of mice was collected for blood routine examinations.Flow cytometry was employed to identify the impact of ginsenoside Rg1 on cell apoptosis and cycle in the bone marrow of AA mice.Additionally,the study further evaluated cytokine levels with enzyme-linked immunosorbent assay and analyzed the expression of key proteins in the MAPK signaling pathway via western blot.RESULTS Administration of CTX led to significant damage to the bone marrow’s structural integrity and a reduction in hematopoietic cells,establishing a model of AA.Ginsenoside Rg1 successfully reversed hematopoietic dysfunction in AA mice.In comparison to the AA group,ginsenoside Rg1 provided relief by reducing the induction of cell apoptosis and inflammation factors caused by CTX.Furthermore,it helped alleviate the blockade in the cell cycle.Treatment with ginsenoside Rg1 significantly alleviated myelosuppression in mice by inhibiting the MAPK signaling pathway.CONCLUSION This study suggested that ginsenoside Rg1 addresses AA by alleviating myelosuppression,primarily through modulating the MAPK signaling pathway,which paves the way for a novel therapeutic strategy in treating AA,highlighting the potential of ginsenoside Rg1 as a beneficial intervention.

Study on improving hematopoietic function of rats with blood deficiency syndrome by Shengxuebao mixture

Background:Shengxuebao mixture(SXBM)is a novel herbal drug approved by China State Food and Drug Administration for the treatment of Leukopenia and iron deficiency anemia caused by radiotherapy and chemotherapy.Methods:To explore the mechanism of SXBM in treating blood deficiency syndrome(BDS).Firstly,network pharmacology and in vivo experiments were used to screen candidate targets and important signaling pathways of SXBM,GO functional enrichment and KEGG pathway analysis were performed.Secondly,a BDS rat model was established to verify the results of the analysis of network pharmacological enrichment.Histopathology and routine peripheral blood examination were observed.The expressions of tumor necrosis factor-α,interleukin(IL)-6,HIF-1αand NF-κB were detected by Western blot,and the expressions of IL-6,IL-1βwere detected by ELISA.Results:62 bioactive components,66 potential targets and 131 signaling pathways of BDS were successfully identified by network pharmacology.Molecular docking simulation techniques showed that key targets tumor necrosis factor-α,IL-6,IL-1βcan dock well with crucial components,and the BDS-related signaling pathways HIF-1 and JAK-STAT play a vital role.The combined model experiment of acetylphenylhydrazine and cyclophosphamide showed that the model group had obvious blood deficiency,and the histopathology and blood routine were effectively restored after administration.Our findings indicate that SXBM’s therapeutic effect on BDS primarily involves the mediation of the HIF-1α/NF-κB signaling pathway and the regulation of hematopoietic factor expression.Conclusion:This study not only affirmed the protective properties of SXBM against BDS but also provided insights into a potential mechanism for blood replenishment in the treatment of BDS using SXBM.

Support of ex vivo expansion,homing and hematopoiesis reconstitution by differentiation inhibiting culture system in hematopoietic cells from mouse marrow

To explore whether differentiation inhibiting culture system (DICS) supports ex vivo expansion,homing and hematopoiesis reconstitution of hematopoietic cells from mouse marrow.Methods DISC were co-cultured with hemapoietic cells from mouse marrow for 7 days.The total number of cells,CFC and Sca-1+ cells were counted.The expanded cells from male donor were transplanted.To female recipients,the homing percentage of Y-Chromosome from male donor in FISH was measured 24 h after transplantation.The number of RBC,WBC and PLT in peripheral blood was counted 3,6,9,12,15,18,25,32 and 42 days after transplantation.Results The total number of cells,CFC and Sca-1+ cells were significantly increased.The homing of expanded cells was increased,and the number of RBC,WBC and PLT was recovered more quickly.Conclusion Differentiation inhibiting culture system (DICS) can support ex vivo expansion,homing and hematopoiesis reconstitution of hematopoietic cells from mouse marrow,and it is a good expansion system.13 refs,3 figs,1 tab.

Hematopoietic Stem Cell Niche in Foetal Liver and Production of Pluripotent Stem Cell-Derived Liver Organoids

There is a considerable demand but limited supply for hematopoietic stem cells (HSCs) in clinics. To meet clinical needs of HSCs, new efforts focus on de novo HSCs generation from pluripotent stem cells (PSCs). Although previous attempts have yielded precursors and progenitors of HSCs, the production of fully functional HSCs has largely been unsuccessful. The failure of PSC-derived HSCs to mature to foetal liver stage is not surprising, as most methods are trying to generate hemogenic endothelium resembling that found in the aorta-gonad-mesonephros (AGM) region, highlighting the importance of understanding human foetal liver niche and developing protocols to mimic this environment. This paper investigates the diverse cellular interactions within the fetal liver niche that contribute to HSC maturation and explores the potential for generating human fetal liver organoids that can recreate these supportive environments in vitro. Such organoids could provide a groundbreaking model for studying HSC maturation and potentially offer a scalable solution for the ex vivo production of functional HSCs, paving the way for advances in both regenerative medicine and hematopoietic stem cell transplantation.

COVID-19 impact in Crohn’s disease patients submitted to autologous hematopoietic stem cell transplantation

BACKGROUND Severe acute respiratory syndrome coronavirus 2 is the virus responsible for coronavirus disease 2019(COVID-19),a disease that has been blamed for inducing or exacerbating symptoms in patients with autoimmune diseases.Crohn's disease(CD)is an inflammatory bowel disease that affects genetically susceptible patients who develop an abnormal mucosal immune response to the intestinal microbiota.Patients who underwent hematopoietic stem cell transplantation(HSCT)are considered at risk for COVID-19.AIM To describe for the first time the impact of COVID-19 in CD patients who had undergone autologous,non-myeloablative HSCT.METHODS In this descriptive study a series of 19 patients were diagnosed with positive COVID-19.For two patients there were reports of the occurrence of two infectious episodes.Parameters related to HSCT,such as time elapsed since the procedure,vaccination status,CD status before and after infection,and clinical manifestations resulting from COVID-19,were evaluated.RESULTS Among the patients with COVID-19,three,who underwent Auto HSCT less than six months ago,relapsed and one,in addition to the CD symptoms,started to present thyroid impairment with positive anti-TPO.Only one of the patients required hospitalization for five days to treat COVID-19 and remained in CD clinical remission.Nine patients reported late symptoms that may be related to COVID-19.There were no deaths,and a statistical evaluation of the series of COVID-19 patients compared to those who did not present any infectious episode did not identify significant differences regarding the analyzed parameters.CONCLUSION Despite the change in CD status in three patients and the presence of nine patients with late symptoms,we can conclude that there was no significant adverse impact concerning COVID-19 in the evaluated patients who underwent HSCT to treat CD.

Patients admitted in the intensive care unit after solid organ or bone marrow transplantation:Retrospective cohort study

BACKGROUND Solid organ transplantation(SOT)and hematopoietic stem cell transplantation(HSCT)revolutionized the survival and quality of life of patients with malignant diseases,various immunologic,and metabolic disorders or those associated with a significant impairment in a patient's quality of life.AIM To investigate admission causes and treatment outcomes of patients after SOT or HSCT treated in a medical intensive care unit(ICU).METHODS We conducted a single-center,retrospective epidemiological study in the medical ICU at the University Hospital Centre Zagreb,Croatia covering the period from January 1,2018 to December 31,2023.RESULTS The study included 91 patients with either SOT[28 patients(30.8%)]or HSCT[63 patients(69.2%)].The median age was 56(43.2-64.7)years,and 60.4%of the patients were male.Patients with SOT had more comorbidities than patients after HSCT[χ^(2)(5,n=141)=18.513,P<0.001].Sepsis and septic shock were the most frequent reasons for admission,followed by acute respiratory insufficiency in patients following HSCT.Survival rate significantly differed between SOT and HSCT[χ^(2)(1,n=91)=21.767,P<0.001].ICU survival was 57%in the SOT and 12.7%in the HSCT group.The need for mechanical ventilation[χ^(2)(1,n=91)=17.081,P<0.001]and vasopressor therapy[χ^(2)(1,n=91)=36.803,P<0.001]was associated with survival.The necessity for acute renal replacement therapy did not influence patients'survival[χ^(2)(1,n=91)=0.376,P=0.54].In the subgroup of patients with infection,90%had septic shock,and the majority had positive microbiological samples,mostly Gram-negative bacteria.The ICU survival of patients with sepsis/septic shock cumulatively was 15%.The survival of SOT patients with sepsis/shock was 45%.CONCLUSION Patients with SOT or HSCT are frequently admitted to the ICU due to sepsis and septic shock.Despite advancements in critical care,the mortality rate of patients with refractory septic shock and multiorgan failure in this patient population is extremely high.Early recognition and timely ICU admittance might improve the outcome of patients,especially after HSCT.

Comprehensive evaluation of nutritional status before and after hematopoietic stem cell transplantation in 170 patients with hematological diseases

Objective： To investigate the nutritional status of patients before and after hematopoietic stem cell transplantation（HSCT）, and explore optimal methods for assessing nutritional status in patients with hematological diseases.Methods： This cohort study enrolled 170 patients who were diagnosed with hematological diseases and underwent allogeneic HSCT in the Department of Hematology, Peking University People＇s Hospital between May2011 and April 2013. We used fixed-point continuous sampling and four nutritional screening tools, Nutritional Risk Screening 2002（NRS-2002）, Mini Nutritional Assessment（MNA）, Subjective Global Assessment（SGA） and Malnutrition Universal Screening Tools（MUST）, in combination with body measurements, to extensively screen and evaluate nutritional risks and status in patients receiving HSCT before entering and after leaving laminar air flow rooms.Results： After HSCT, patients had significant reduction in weight, hip circumference, waist-hip ratio, calf circumference, mid-upper arm circumference, and suprailiac skinfold thickness compared with pre-HSCT measurements. Before HSCT, NRS-2002 identified that 21.2% of patients were at nutritional risks, compared with100% after HSCT. MUST indicated that before HSCT, 11.77% of patients were at high nutritional risk,compared with 59.63% after HSCT. MNA assessed that 0.06% of patients were malnourished before HSCT,compared with 19.27% after HSCT. SGA identified that before HSCT, 1.76% of patients had mild to severe malnutrition, which increased to 83.3% after HSCT. There is a significant increase in the nutritional risk and malnutrition in patients who received HSCT.Conclusions： Before HSCT, some patients already had nutritional risk or nutritional deficiencies, and prompt and close nutritional screening or assessment should be performed. The nutritional status of patients after HSCT was generally deteriorated compared with that before transplantation. Body measurements should be taken more frequently during the subsequent treatment window in the laminar air flow rooms. After HSCT, it is recommended to combine MNA and SGA to fully evaluate the nutritional status, and thus provide timely and reasonable nutritional support.

Nutritional assessment with different tools in leukemia patients after hematopoietic stem cell transplantation

Objective： Correct nutritional assessment is essential for leukemia patients after hematopoietic stem cell transplantation （HSCT）. This study aimed to investigate the best nutritional assessment method for leukemia patients after HSCT, and find the possible nutritional risk of the patients during the transplantation process in order to intervene in the patients with nutritional risks and undernourished patients timely, so that the entire transplantation process could be successfully completed. Methods： A prospective study was performed in 108 leukemia patients after HSCT, and different nutritional assessment methods, including nutritional risk screening 2002 （NRS2002）, mini nutritional assessment （MNA）, subjective globe assessment （SGA） and malnutritional universal screening tools （MUST）, were used. The associations between nutritional status of these patients and nutritional assessment methods were analyzed. Results： A total of 108 patients completed SGA, and 99 patients completed NRS2002, MNA and MUST. During the treatment process, 85.2% of the patients lost weight, wherein, 50% lost weight greater than 5%, and 42.6% had significantly reduced food intake. For nutritional risk assessment, the positive rates of NRS2002, MNA and MUST were 100%, 74.7% and 63.6%, respectively. There was a significant difference （P〈0.05） among the positive rates of NRS2002, MNA and MUST. In undernutrition assessment, the positive rate of SGA （83.3%） was significantly higher than that of MNA （17.2%） （P〈0.05）, and the incidence rate of nutritional risk among leukemia patients _〈30 years old was greater than that of patients 〉30 years old （P〈0.05）. Conclusions： Patients with leukemia were in poor nutritional status during and after HSCT. The leukemia patients 〈30 years old had a greater incidence rate of nutritional risk. As nutritional risk screening tool, the specificity of NRS2002 is not high, but it can be used for evaluating nutritional deficiencies. MNA is a good nutritional risk screening tool, but not an adequate tool for nutritional assessment. If assessment of undernutrition is necessary, the combination of all these screening tools and clinical laboratory indicators should he applied to improve accuracy.

Regulation of hematopoiesis and the hematopoietic stem cell niche by Wnt signaling pathways

Hematopoietic stem cells （HSCs） are a rare population of cells that are responsible for life-long generation of blood cells of all lineages. In order to maintain their numbers, HSCs must establish a balance between the opposing cell fates of self-renewal （in which the ability to function as HSCs is retained） and initiation of hematopoietic differentiation. Multiple signaling pathways have been implicated in the regulation of HSC cell fate. One such set of pathways are those activated by the Wnt family of ligands. Wnt signaling pathways play a crucial role during embryogenesis and deregulation of these pathways has been implicated in the formation of solid tumors. Wnt signaling also plays a role in the regulation of stem cells from multiple tissues, such as embryonic, epidermal, and intestinal stem cells. However, the function of Wnt signaling in HSC biology is still controversial. In this review, we will discuss the basic characteristics of the adult HSC and its regulatory microenvironment, the ＂niche＂, focusing on the regulation of the HSC and its niche by the Wnt signaling pathways.

Autologous hematopoietic stem cell transplantation in chemotherapy-sensitive lymphoblastic lymphoma: treatment outcome and prognostic factor analysis

Objective： The study evaluated the effectiveness of autologous hematopoietic stem cell transplantation （AHSCT） in the treatment of lymphoblastic lymphoma （LL）. Methods： We relxospectively analyzed the data from 41 patients with chemotherapy-sensitive LL who underwent hematopoietic stem cell transplantation （HSCT） from December 1989 to December 2009 in a single institution. Results： HSCT was conducted as first-line consolidation therapy and salvage therapy in 36 and 5 patients, respectively. The median follow-up was 97.1 months （range, 24.6-173.1 months）. The 5-year overall survival （OS） and event-free survival （EFS） rate were 64% and 47% for the initially treated patients, respectively, and were both 20% for the relapsed ones. Bone marrow （BM） involvement and chemotherapy cycles prior to transplantation were identified as significant prognostic factors for EFS in multivariate analysis. Conclusions These results confirm that AHSCT is a reasonable option for chemotherapy-sensitive LL patients in first complete remission （CR1）.

Donor-Derived CD19-Targeted T Cell Infusion Eliminates B Cell Acute Lymphoblastic Leukemia Minimal Residual Disease with No Response to Donor Lymphocytes after Allogeneic Hematopoietic Stem Cell Transplantation

Leukemia relapse is still the leading cause of treatment failure after allogeneic hematopoietic stem cell transplantation (allo-HSCT) for B cell acute lymphoblastic leukemia (B-ALL). Relapsed patients with BALL after allo-HSCT have a very short median survival. Minimal residual disease (MRD) is predictive of forthcoming hematological relapse after hematopoietic stem cell transplantation (HSCT);furthermore, eliminating MRD effectively prevents relapse. Donor lymphoblastic infusion (DLI) is the main established approach to treat B-ALL with MRD after allo-HSCT. However, about one-third of patients with MRD are non-responsive to DLI and their prognosis worsens. Although donor-derived cluster of differentiation (CD)19-directed chimeric antigen receptor-modified (CAR) T cells (CART19s) can potentially cure leukemia, the efficiency and safety of infusions with these cells have not yet been investigated in patients with MRD after HSCT. Between September 2014 and February 2018, six patients each received one or more infusions of CART19s from HSCT donors. Five (83.33%) achieved MRD-negative remission, and one case was not responsive to the administration of CAR T cells. Three of the six patients are currently alive without leukemia. No patient developed acute graft-versus-host disease (aGVHD), and no patient died of cytokine release syndrome. Donor-derived CAR T cell infusions seem to be an effective and safe intervention for patients with MRD in B-ALL after allo-HSCT and for those who were not responsive to DLI.

WJSC 6^(th) Anniversary Special Issues(1):Hematopoietic stem cell transplantation Allogeneic hematopoietic cell transplant for acute myeloid leukemia:Current state in 2013 and future directions

Acute myeloid leukemia(AML)represents a heterogeneous group of high-grade myeloid neoplasms of the elderly with variable outcomes.Though remissioninduction is an important first step in the management of AML,additional treatment strategies are essential to ensure long-term disease-free survival.Recent pivotal advances in understanding the genetics and molecular biology of AML have allowed for a risk-adapted approach in its management based on relapse-risk.Allogeneic hematopoietic cell transplantation(allo-HCT)represents an effective therapeutic strategy in AML providing the possibility of cure with potent graft-versus-leukemia reactions,with a demonstrable survival advantage in younger patients with intermediate-or poor-risk cytogenetics.Herein we review the published data regarding the role of allo-HCT in adults with AML.We searched MEDLINE/PubMed and EMBASE/Ovid.In addition,we searched reference lists of relevant articles,conference proceedings and ongoing trial databases.We discuss the role of allo-HCT in AML patients stratified by cytogenetic-and molecular-risk in first complete remission,as well as allo-HCT as an option in relapsed/refractory AML.Besides the conventional sibling and unrelated donor allografts,we review the available data and recent advances for alternative donor sources such as haploidentical grafts and umbilical cord blood.We also discuss conditioning regimens,including reduced intensity conditioning which has broadened the applicability of allo-HCT.Finally we explore recent advances and future possibilities and directions of allo-HCT in AML.Practical therapeutic recommendations have been made where possible based on available data and expert opinion.

Hematopoietic stem cell-derived adipocytes and fibroblasts in the tumor microenvironment

The tumor microenvironment(TME) is complex and constantly evolving. This is due, in part, to the crosstalk between tumor cells and the multiple cell types that comprise the TME, which results in a heterogeneous population of tumor cells and TME cells. This review will focus on two stromal cell types, the cancerassociated adipocyte(CAA) and the cancer-associated fibroblast(CAF). In the clinic, the presence of CAAs and CAFs in the TME translates to poor prognosis in multiple tumor types. CAAs and CAFs have an activated phenotype and produce growth factors, inflammatory factors, cytokines, chemokines, extracellular matrix components, and proteases in an accelerated and aberrant fashion. Through this activated state, CAAs and CAFs remodel the TME, thereby driving all aspects of tumor progression, including tumor growth and survival, chemoresistance, tumor vascularization, tumor invasion, and tumor cell metastasis. Similarities in the tumorpromoting functions of CAAs and CAFs suggest that a multipronged therapeutic approach may be necessary to achieve maximal impact on disease. While CAAs and CAFs are thought to arise from tissues adjacent to the tumor, multiple alternative origins for CAAs and CAFs have recently been identified. Recent studies from our lab and others suggest that the hematopoietic stem cell, through the myeloid lineage, may serve as a progenitor for CAAs and CAFs. We hypothesize that the multiple origins of CAAs and CAFs may contribute to the heterogeneity seen in the TME. Thus, a better understanding of the origin of CAAs and CAFs, how this origin impacts their functions in the TME, and thetemporal participation of uniquely originating TME cells may lead to novel or improved anti-tumor therapeutics.

Decitabine for Relapsed Acute Lymphoblastic Leukemia after Allogeneic Hematopoietic Stem Cell Transplantation

Relapse after allogeneic hematopoietic stem cell transplantation（allo-HSCT） remains a main question on treatment failure. Current strategies for management that usually include salvage chemotherapy, donor lymphocytic infusion and second transplantation. Our study assessed the efficacy of decitabine（DAC） for treating patients with acute lymphoblastic leukemia（ALL） who relapsed after allogeneic hematopoietic stem cell transplantation（allo-HSCT）. We retrospectively analyzed the outcomes of 12 patients with relapsed ALL after allo-HSCT who received DAC therapy. Nine patients received DAC combined with chemotherapy and donor stem cell infusion, and 3 patients received single-agent DAC. Ten of the 12 patients achieved complete remission（CR）, 1 achieved a partial remission（PR）, and 1 had no response（NR） after treatment at the latest follow-up（LFU）, the median survival was 11.2 months（range, 3.8–34, 7 months）. The 1-and 2-year overall survival（OS） rates were 50%（6/12） and 25%（3/12）, respectively. Five patients were still alive; 4 had maintained CR and 1 was alive with disease. Patients with Philadelphia chromosome-positive ALL had higher survival rate than patients with Philadelphia chromosome-negative ALL（57.1% vs. 20%）. No aggravated flares of graft-versus-host disease（GVHD） were observed during DAC treatment. Therefore, DAC may be a promising therapeutic agent for ALL recurrence after allo-HSCT.