Repetitive administration of cultured human CD34+cells improve adenine-induced kidney injury in mice

BACKGROUND There is no established treatment to impede the progression or restore kidney function in human chronic kidney disease(CKD).AIM To examine the efficacy of cultured human CD34+cells with enhanced proliferating potential in kidney injury in mice.METHODS Human umbilical cord blood(UCB)-derived CD34+cells were incubated for one week in vasculogenic conditioning medium.Vasculogenic culture significantly increased the number of CD34+cells and their ability to form endothelial progenitor cell colony-forming units.Adenineinduced tubulointerstitial injury of the kidney was induced in immunodeficient non-obese diabetic/severe combined immunodeficiency mice,and cultured human UCB-CD34+cells were administered at a dose of 1×106/mouse on days 7,14,and 21 after the start of adenine diet.RESULTS Repetitive administration of cultured UCB-CD34+cells significantly improved the time-course of kidney dysfunction in the cell therapy group compared with that in the control group.Both interstitial fibrosis and tubular damage were significantly reduced in the cell therapy group compared with those in the control group(P<0.01).Microvasculature integrity was significantly preserved(P<0.01)and macrophage infiltration into kidney tissue was dramatically decreased in the cell therapy group compared with those in the control group(P<0.001).CONCLUSION Early intervention using human cultured CD34+cells significantly improved the progression of tubulointerstitial kidney injury.Repetitive administration of cultured human UCB-CD34+cells significantly improved tubulointerstitial damage in adenine-induced kidney injury in mice via vasculoprotective and anti-inflammatory effects.

THE EFFECT OF STEM CELL FACTOR, INTERLEUKIN-6 AND ERYTHROPOIETIN ON EXPANSION OF CD34^+ CELLS FROM HUMAN UMBILICAL CORD BLOOD

CD34+ cells from human umbilical cord blood were purified by Dynal beads M-450 CD34 immunoselection system and cultured in the presence of various cytokines alone or in combination, including stem cell factor (SCF), interleukin-6 (IL-6) and erythropoietin (EPO). The results revealed that: (D In methylcellulose culture, the plating efficiencies of purified cord blood CD34+ cells were much different when stimulated by various cytokines. IL-6 alone had the lowest colo-ny yield, while the combination of SCF, IL-6 and EPO had the highest yield. ② In the suspension culture, IL-6 alone or IL-6 + EPO had little expanding effect on cord blood CD34+ celis, the other cytokine combinations could expand cord blood CD34+ celis at different Ievels. Among them, the combination of SCF, IL-6 and EPO had the maximal expanding effect on cord blood CD34+ celis, the number of progenitor celis peaked at day 21, about 29-fold increase and nucleated celis increased approximately 3676-fold at day 28. The expanding effect of

Autologous CD34^+ and CD133^+ stem cells transplantation in patients with end stage liver disease

AIM:To assess the utility of an autologous CD34 + and CD133 + stem cells infusion as a possible therapeutic modality in patients with end-stage liver diseases.METHODS:One hundred and forty patients with endstage liver diseases were randomized into two groups.Group 1,comprising 90 patients,received granulocyte colony stimulating factor for five days followed by autologous CD34 + and CD133 + stem cell infusion in the portal vein.Group 2,comprising 50 patients,received regular liver treatment only and served as a control group.RESULTS:Near normalization of liver enzymes and improvement in synthetic function were observed in 54.5% of the group 1 patients;13.6% of the patients showed stable states in the infused group.None of the patients in the control group showed improvement.No adverse effects were noted.CONCLUSION:Our data showed that a CD34 + and CD133 + stem cells infusion can be used as supportive treatment for end-stage liver disease with satisfactory tolerability.

Autologous mobilized peripheral blood CD34^+ cell infusion in non-viral decompensated liver cirrhosis

AIM: To study the effect of mobilized peripheral blood autologous CD34 positive(CD34+) cell infusion in patients with non-viral decompensated cirrhosis.METHODS: Cirrhotic patients of non-viral etiology were divided into 2 groups based on their willingness to be listed for deceased donor liver transplant(DDLT)(control, n = 23) or to receive autologous CD34+ cell infusion through the hepatic artery(study group, n= 22). Patients in the study group were admitted to hospital and received granulocyte colony stimulating factor injections 520 μg/d for 3 consecutive days to mobilize CD34+ cells from the bone marrow. On day 4,leukapheresis was done and CD34+ cells were isolated using CliniMAC magnetic cell sorter. The isolated CD34+ cells were infused into the hepatic artery under radiological guidance. The patients were discharged within 48 h. The control group received standard of care treatment for liver cirrhosis and were worked up for DDLT as per protocol of the institute. Both groups were followed up every week for 4 wk and then every month for 3 mo.RESULTS: In the control and the study group, the cause of cirrhosis was cryptogenic in 18(78.2%) and16(72.72%) and alcohol related in 5(21.7%) and6(27.27%), respectively. The mean day 3 cell count(cells/μL) was 27.00 ± 20.43 with a viability of 81.84± 11.99%. and purity of 80%-90%. Primary end point analysis revealed that at 4 wk, the mean serum albumin in the study group increased significantly(2.83± 0.36 vs 2.43 ± 0.42, P = 0.001) when compared with controls. This improvement in albumin was,however, not sustained at 3 mo. However, at the end of3 mo there was a statistically significant improvement in serum creatinine in the study group(0.96 ± 0.33 vs 1.42 ± 0.70, P = 0.01) which translated into a significant improvement in the Model for End-Stage Liver Disease score(15.75 ± 5.13 vs 19.94 ± 6.68,P = 0.04). On statistical analysis of secondary end points, the transplant free survival at the end of 1 mo and 3 mo did not show any significant difference(P =0.60) when compared to the control group. There was no improvement in aspartate transaminase, alanine transaminase, and bilirubin at any point in the study population. There was no mortality benefit in the study group. The procedure was safe with no procedural or treatment related complications.CONCLUSION: Autologous CD 34+ cell infusion is safe and effectively improves liver function in the short term and may serve as a bridge to liver transplantation.

A familiar stranger:CD34 expression and putative functions in SVF cells of adipose tissue

Human adipose tissue obtained by liposuction is easily accessible and an abundant potential source of autologous cells for regenerative medicine applications. After digestion of the tissue and removal of differentiated adipocytes, the so-called stromal vascular fraction (SVF) of adipose, a mix of various cell types, is obtained. SVF contains mesenchymal fibroblastic cells, able to adhere to culture plastic and to generate large colonies in vitro , that closely resemble bone marrow-derived colony forming units-fibroblastic, and whose expanded progeny, adipose mesenchymal stem/stromal cells (ASC), show strong similarities with bone marrow mesenchymal stem cells. The sialomucin CD34, which is well known as a hematopoietic stem cell marker, is also expressed by ASC in native adipose tissue but its expression is gradually lost upon standard ASC expansion in vitro . Surprisingly little is known about the functional role of CD34 in the biology and tissue forming capacity of SVF cells and ASC. The present editorial provides a short introduction to the CD34 family of sialomucins and reviews the data from the literature concerning ex- pression and function of these proteins in SVF cells and their in vitro expanded progeny.

Expression of Caspase－3 in Cord Blood CD34^＋ Cells during Culture in vitro

Objective: To investigate the expression and significance of caspase-3 protein in CD34^+ cells from cord blood (CB) during culture in vitro with different growth factors. Methods: RT-PCR, Western blot and flow cytometry techniques were used to detect the expression of caspase-3 in CD34^+ CB cells during culture in vitro. Results: Caspase-3 mRNA was constitutively expressed at a low level in freshly isolated CD34^+ cells. The expression of caspase-3 mRNA and protein was upregulated when these cellswere first expanded in suspension culture with growth factors for 3 days. However, only the 32 kDa inactive caspase-3 proenzyme was detected in the freshly isolated CD34^+ cells as well as during the first 3 days expansion with cytokines. With longer culture time in vitro, especially in the presence of the combination of IL-3, IL-6 and GM-CSF, caspase-3 was activated and a cleavage product of 20 kDa became detectable.Conclusion: Caspase-3 is involved in apoptosis of primitive CB CD34^+ cells during expansion in vitro.

Hematopoietic stem cells in research and clinical applications:The“CD34 issue”

In this paper,experimental findings concerning the kinetics of hematopoietic reconstitution are compared to corresponding clinical data.Although not clearly apparent,the transplantation practice seems to confirm the basic proposals of experimental hematology concerning hematopoietic reconstitution resulting from successive waves of repopulation stemming from different subpopulations of progenitor and stem cells.One of the "f irst rate" parameters in clinical transplantations in hematology;i.e.the CD34+ positive cell dose,has been discussed with respect to the functional heterogeneity and variability of cell populations endowed by expression of CD34.This parameter is useful only if the relative proportion of stem and progenitor cells in the CD34+ cell population is more or less maintained in a series of patients or donors.This proportion could vary with respect to the source,pathology,treatment,processing procedure,the graft ex vivo treatment and so on.Therefore,a universal dose of CD34+ cells cannot be def ined.In addition,to avoid further confusion,the CD34+ cells should not be named "stem cells" or "progenitor cells" since these denominations only concern functionally characterized cell entities.

HUMAN PRIMITIVE HEMATOPOIETIC PROGENITOR CELLS ARE MORE ENRICHED IN CD34^+CD38^- POPULATION THAN IN CD34^+CD38^+ POPULATION

To clarify the hematopoietic potential of various sub-classes of human hematopoietic progenitor cells, we used a multicolor staining protocol in conjunction with anti-CD34 and -CD38 McAb. We characterized two cell fractions in CD34+cells with or without CD38 expression. A clonogenic assay showed that most CFC were present in CD34+CD38+ population. Morphologic analysis showed that blast-like cells were more enriched in the CD34+CD38 fraction. To clarify the biologic differences between both fractions, we examined the more primitive progenitor cell function by assessing long-term culture-initiating cells (LTC-IC) on the stromal cells. At the first two weeks, more CF.C harvested from the culture in the fractions initiated with both populations. However, more LTC-IC were present during weeks 4 to 12 in the CD34+CD38- population. These results indicate the primitive progenitors are more enriched in CD34+CD38 population than in CD34+CD38+ cells.

High frequency of CD34+CD38-/low immature leukemia cells is correlated with unfavorable prognosis in acute myeloid leukemia

AIM To evaluate the importance of the CD34+CD38-cell population when compared to the CD34+CD38+/low and CD34+CD38+/high leukemic cell sub-populations and to determine its correlations with leukemia characteristics and known prognostic factors, as well as with response to therapy and survival.METHODS Two hundred bone marrow samples were obtained at diagnosis from 200 consecutive patients with newly diagnosed acute myeloid leukemia(AML) were studied between September 2008 and December 2010 at our Institution(Hematology Department, Lyon, France). The CD34/CD38 cell profile was analyzed by multiparameter flowcytometry approach using 8 C panels and FACS CANTO and Diva software(BD Bioscience).RESULTS We analyzed CD34 and CD38 expression in bone marrow samples of 200 AML patients at diagnosis, and investigated the prognostic value of the most immature CD34+CD38-population. Using a cut-off value of 1% of CD34+CD38-from total "bulk leukemic cells" we found that a high(> 1%) level of CD34+CD38-blasts at diagnosis was correlated with advanced age, adverse cytogenetics as well as with a lower rate of complete response after induction and shorter disease-free survival. In a multivariate analysis considering age, leukocytosis, the % of CD34+ blasts cells and the standardized cytogenetic and molecular risk subgroups, a percentage of CD34+CD38-leukemic cells > 1% was an independent predictor of DFS [HR = 2.8(1.02-7.73), P = 0.04] and OS [HR = 2.65(1.09-6.43), P = 0.03].CONCLUSION Taken together, these results show that a CD34/CD38 "backbone" for leukemic cell analysis by multicolour flowcytometry at diagnosis provides useful prognostic information.

The Role of Bcl-2, CD10 and CD34 Expression in Differentiation between Basal Cell Carcinoma and Trichoepithelioma

Background: Basal cell carcinoma (BCC) and trichoepithelioma (TE) have some similarities clinically and histologically. The aim of this work is to evaluate the role of Bcl-2, CD10 and CD34 in differentiation between BCC and TE. Methods: The immunohistochemical expression of Bcl-2, CD10 and CD34 was evaluated in 20 BCCs and 12 TEs in a retrospective study. The localization of these markers in tumor and stromal cells was determined and comparison between BCC and TE was done. Immunohistochemistry for Bcl-2, CD10 and CD34 was performed on sections obtained from formalin-fixed, paraffin-embedded blocks. Bcl-2, CD10 and CD34 immunoreactivity in the stromal and/or tumor cells was determined as follows: negative (0);1+ (10% - 50% positive cells);and 2+ (>50% positive cells). Results: In BCC (20 cases), the expression of Bcl-2 in stromal cells showed (0) immunoreactivity in 8 cases (40%), (1+) immunoreactivity in 7 cases (35%), and (2+) immunoreactivity in 5 cases (25%). Tumoral cells showed diffuse positivity in 20 out of 20 cases (100%), (1+) immunoreactivity in 5 cases (25%) and (2+) immunoreactivity in 15 cases (75%). On the other hand, the expression of Bcl2 in TE, 4 cases showed positive stromal cells out of 12 (33.33%), (1+) immunoreactivity in 2 cases (16.6%) and (2+) immunoreactivity in 2 cases (16.6%), and 8 cases showed no immunoreactivity. Tumoral cells showed positivity in 12 out of 12 cases (100%), (1+) immunoreactivity in 5 cases (41.6%), (2+) immunoreactivity in 7 cases (58.3%). In BCC cases, the expression of CD10 was noted in stromal cells in 8 out of 20 cases (40%), 5 cases showed positivity in stromal and basaloid cells and 3 cases showed positivity in stromal cells only, and 12 cases showed no immunoreactivity (60%). Tumor cells showed positivity in 11 cases out of 20 (55%), (1+) immunoreactivity in 6 cases (30%), (2+) in 5 cases (25%), and 9 cases showed no immunoreactivity (45%). On the other hand, the expression of CD10 in TE 7 cases showed positive stromal cells out of 12 (58.33%), (1+) immunoreactivity in 5 cases (41.6%) and (2+) in 2 cases (16.6%), and 5 cases showed no immunoreactivity (41.66%). Tumor cells showed positivity in 5 cases out of 12 (41.66%), (1+) immunoreactivity in 4 cases (33.33%) and (2+) in 1 case (8.3%), and 7 cases showed no immunoreactivity (58.33%). In BCC cases, the expression of CD34 was noted in stromal cells in14 cases out of 20 cases (70%), (1+) immunoreactivity in 10 cases (50%) and (2+) in 4 cases (20%), and 6 cases showed no immunoreactivity (30%). On the other hand, the expression of CD34 in TE, 10 cases showed positive stromal cells out of 12 (83.33%), (1+) immunoreactivity in 6 cases (50%) and (2+) in 4 cases (33.33%), and 2 cases showed no immunoreactivity (16.6%). Tumor cells showed no immunoreactivity for CD 34 in both BCC and trichoepithelioma, (100%) negative tumor cells. Significant difference of tumor\stromal cells immunoreactivity for Bcl-2 and CD34 in both BCC and TE but it was insignificant for CD10. Conclusion: We conclude that Bcl-2 CD10, CD34 are useful markers in the differential diagnosis of BCC versus TE.

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.

Apoptotic bone marrow CD34+ cells in cirrhotic patients

AIM: To access the frequency and level of apoptotic CD34+ cells isolated from the marrow fluid of patients with post-hepatitis cirrhosis. METHODS: The frequency of bone marrow CD34+ cells and apoptotic bone marrow CD34+ cells in 31 inpatients with post-hepatitis cirrhosis (cirrhosis group), and 15 out-patients without liver or blood disorders (control group) was calculated by flow cytometry. Parameters were collected to evaluate liver functions of patients in cirrhosis group. RESULTS: The percentage of normal bone marrow CD34+ cells was 6.30% ± 2.48% and 1.87% ± 0.53% (t = 3.906, P < 0.01) while that of apoptotic marrowCD34+ cells was 15.00% ± 15.81% and 5.73% ± 1.57% (t = 2.367, P < 0.05) in cirrhosis and control groups, respectively. The percentage of apoptotic marrow CD34+ cells was 6.25% ± 3.30% and 20.92 ± 18.5% (t = 2.409, P < 0.05) in Child-Pugh A and Child-Pugh B + C cirrhotic patients, respectively. The percentage of late apoptotic marrow CD34+ cells was positively correlated with the total bilirubin and aspartate aminotransferase serum levels in patients with cirrhosis. CONCLUSION: The status of CD34+ marrow cells in cirrhotic patients may suggest that the ability of hematopoietic progenitor cells to transform into mature blood cells is impaired.

Apoptosis of Leukemia Cells Induced by CD34^+ Cells Transferred Exogenous Fas Ligand

To assess the value of CD34 + cells transferred exogenous Fas ligand (FasL) in inducing apoptosis of human leukemic cells, the CD34 + cells transfected with F asL or without, pretreated with mitomycin C, was mixed with leukemic cell line U937 cells in presence or absence of daunorubicin (DNR) or cytosine arabinoside (Ara C). After l8 h, apoptosis of cells was detected by FCM and TUNEL. Induced for l8 h by CD34 + cells transfected with FasL or without, the ratio of apoptos is of U937 cells was (5.0±1.3) %, (10.8±0.6) % ( P < 0.01), respectively. Induced by FasL +CD34 ++DNR, FasL +CD34 ++Ara C, the ratio was (13.4±1.0) % ( P < 0.05), (17.9±1.3)% ( P <0.01), respectively. The result demonstrated that CD34 + cells transfected with exogenous FasL could induce apoptosis of human leukemic cells and showed a cytotoxic synergistic effect when used in combination with chemotherapeutic drugs, suggesting that it was possible to develop a new method in treatment of leukemia.

Effect of Homoharringtonine on Bone Morrow CD34^+CD7^+ Cells in Chronic Granulocytic Leukemia

Objective： To explore the effect of homoharringtonine （HHT） on bone morrow CD34^＋CD7^＋ cells in chronic granulocytic leukemia （CGL）. Methods： The changes of bone morrow CD34^＋CD7^＋ cells were observed after the treatment of HHT in 23 cases with CGL. The proliferation and apoptosis of CD34^＋CD7^＋ cells treated with HHT in vitro were studied. Results： The proportion of CD34^＋CD7^＋ cells in CGL （0.145±0.021） was higher than that of normal control （0.052±0.013）. The proportion of CD34^＋CD7^＋ cells in patients who got cytogenetic responses to HHT （0.072±0.020） decreased remarkably, but not in those patients who did not got cytogenetic responses to HHT, （0.137±0.023）. the proliferation of CD34^＋ cells was inhibited and the proportion of CD34^＋CD7^＋ cells decreased after cultured with HHT （0.134 in 24 h, 0.126 in 48 h and 0.102 in 72）. The apoptosis rate of CD34^＋CD7^＋ cells was higher than that in CD34^＋CDT cells （35.39%±4.39% versus 24.57%±4.01%, P〈0.05） 72 h after culture with HHT. Conclusion： The proportion of CD34^＋CD7^＋ cells in CGL was higher than that of normal control and HHT may inhibit the proliferation and induce apoptosis of bone marrow CD34^＋CD7^＋ cells.

Separation of CD34 Positive Cells and Determination of Surface Homing Antigen

To study the differences in homing potential between bone marrow cells and umbilical blood cells, CD34 positive cells were obtained from bone marrow (BM) and umbilical blood (UB) by the direct cell separation with domestic immunomagnetic beads. The expression of the two adhesion molecules CD11a/CD18 and CD44 were examined. After separation, CD34 positive cells accounted for 51 %-82 % of the harvested cells and dye-resistance rate was 82 %-88 %. The expression of CD11a/CD18 and CD44 on the surfaces of UB cells was 49. 6 % 1 10. 2 % and 37. 7 % ± 10. 3 % respectively. On BM cells they were 50. 2 % ± 6. 2 % and 34 % ± 13. 3 % respectively. There were no significant differences in the expression of these two molecules. It was concluded .that the cell separation method with domestic immunomagnetic beads was effective and the stem cells from UB could serve as an alternative source for transplantation.

Isolation and Characterization of Human CD34^+ Hematopoietic Progenitor Cells by High-gradient Magnetic Cell Sorting

Using a high-gradient magnetic cell sorting (MACS) system, CD34^+ cells were isolated from human bone marrow, cord blood, peripheral blood, and cultured in CFU system. The results showed that the excellent recovery (75%) and highest purity (95-99%) were acquired by using the MACS separation system, and the most CFCs were present in CD34^+ population, but not in CD34 fraction by clonogenic assays. The isolation of pure hematopoietic stem cells and progenitor cells is of experimental and clinical importance.

PERIPHERAL BLOOD CD34^+ CELL MOBILIZATION IN 42 PATIENTS WITH SEVERE AUTOIMMUNE DISEASE

Objective To evaluate the feasibility and safety of peripheral CD34+ cell mobilization in patients with severe autoimmune disease. Methods Forty-two patients underwent a total of 46 mobilizations by the regimen of cyclophosphamide 2-3 g/m2 +recombinant human granulocyte colony stimulating factor (rhG-CSF) 5 μg·kg-1·d-1. The positive selection of CD34+ cell was performed through the CliniMACS. Results In 8.1±2.3 days after administration of cyclophosphamide, the peripheral white blood cell and mononuclear cell (MNC) decreased to the lowest level. In 3.7±1.6 days after injection of rhG-CSF, the peripheral absolute MNC and CD34+ cell counts were 0.95×109/L and 0.035×109/L, respectively. After 2.4±0.6 times of leukapheresis, there gained 4.46×108/kg of MNC and 5.26×106/kg of CD34+, respectively. After mobilization, the underlying diseases were ameliorated more or less. In systemic lupus erythematosus (SLE) patients, SLE Disease Activity Index (SLEDAI) decreased from a median of 17 to 3 (P<0.01). In rheumatic arthritis patients, an American College of Rheumatology criteria for 20%(ACR20) response was achieved in all five patients. Totally, 17.4% of patients whose absolute neutrophil count <0.5×109/L suffered infection, and 31.0% of patients had bone pain after the injection of rhG-CSF. Two patients suffered severe complications, one with acute renal failure and recovered by hemodialysis, the other died of thrombotic thrombocytopenic purpura. Failed mobilization occurred in three patients. Conclusions Sufficient CD34+ cells can be mobilized by low dose of cyclophosphamide and rhG-CSF. CD34+ cell mobilization for treatment of severe autoimmune disease not only is appropriate in both effectiveness and safety but ameliorates disease also.

<i>In vitro</i>differentiation of human umbilical cord-derived mesenchymal stem cells into CD34⁺cells via CD34 antibody

CD34+cells differentiated from mesenchymal stem cells (MSCs) have a strong biological function in cardiovascular regeneration. However, the molecular mechanisms of and the methods to improve the CD34+ cell differentiation from MSCs, especially from human MSCs (hUC-MSCs) are still unclear. In the current study, the effect of CD34 antibody on the CD34+ cell differentiation from human umbilical cord (UC)-derived MSCs (hUC-MSCs) is determined. The results have demonstrated that the expression of cd34 protein is significantly increased in hUC-MSCs treated with CD34 antibody. In addition, the cell proliferation is increased in hUC-MSCs after treatment with CD34 antibody. Moreover, the expression of PI3K, AKT, p-AKT proteins, which are signaling molecules related to stem cell differentiation, is increased by CD34 antibody. The results suggest that CD34 antibody could promote the differentiation of hUC-MSCs into CD34+ cells and PI3K/AKT may be involved in this important process.