Incidence and clinical characteristics of engraftment syndrome after syngeneic hematopoietic stem cell transplantation in patients with hematological diseases / 中华血液学杂志

Objective: To explore the incidence and clinical characteristics of engraftment syndrome (ES) after syngeneic hematopoietic stem cell transplantation (syn-HSCT) in patients with hematological diseases. Methods: The clinical data of 21 patients who received syn-HSCT at People's Hospital of Peking University from January 1994 to May 2018 were retrospectively analyzed. Results: Seven (33.3% ) of 21 patients developed ES. The onset of ES symptoms occurred at a median of 8 (range: 5-13) days after HSCT, and the diagnosis of ES occurred at a median of 10 (range: 7-14) days after HSCT. Steroids were administered immediately after the diagnosis of ES, the median time of symptom continuance was 2 (range: 1-5) days, and all patients showed complete resolution of ES symptoms. In the multivariate analysis, patients with acute myeloid leukemia and faster neutrophil reconstitution were the risk factors for ES (HR=15.298, 95% CI 1.486-157.501, P=0.022, and HR=17.459, 95% CI 1.776-171.687, P=0.014) . Meanwhile, there was no significant difference in the overall survival and disease-free survival between patients with ES and those without ES. Conclusion: A high incidence of ES was observed in syn-HSCT recipients. Moreover, the prognosis of ES was excellent.

Research Advances on Strategies to Promote Homing and Engraftment of Hematopoietic Stem Cells--Review / 中国实验血液学杂志

The homing and engraftment of hematopoietic stem cells (HSC) into bone marrow is the first critical step for successful clinical hematopoietic stem cell transplantation (HSCT). SDF-1 / CXCR4 is considered to be a very promising target to promote HSC homing. In recent years, with the in-depth research on the HSC homing, a variety of new strategies for promoting HSC homing and engraftment have been explored, such as nuclear hormone receptor, histone deacetylase inhibitor, prostaglandin and metabolic regulation, so as to increase the success rate of HSCT and improve the survival of patients. In this review, the recent research advances in the mechanism of HSC homing and strategies to promote HSC homing and engraftment were summarized and discussed.

Engraftment syndrome / 中国小儿急救医学

Engraftment syndrome (ES) is a clinical syndrome that occurs after hematopoietic stem cell transplantation and during the recovery process of neutrophils.The main clinical manifestations include non-infectious fever, rash, capillary leakage and non-cardiogenic pulmonary edema, which may be similar with many early complications after transplantation.Therefore, it is sometimes difficult to be diagnosed and differentiated among different kinds of complications.Typical ES is self-limiting and has good response to steroids.However, patients with ES may result in encephalopathy and multi-organ failure if it is untreated without notice.In this review, we discussed the pathophysiological mechanisms, clinical manifestations, diagnosis and differential diagnosis, risk factors, treatment and prognosis of ES, aiming to provide guidance and reference for clinicians.

Better Failure-Free Survival and Graft-versus-Host Disease-Free/Failure Free Survival with Fludarabine-Based Conditioning in Stem Cell Transplantation for Aplastic Anemia in Children

BACKGROUND: This study aimed to assess the outcome of stem cell transplantation (SCT), including overall survival (OS), failure-free survival (FFS) and graft-versus-host disease (GvHD)-free/failure-free survival (GFFS), and to analyze prognostic factors in children with aplastic anemia (AA).METHODS: From 1991 to 2018, 43 allogeneic SCT recipients were enrolled in the study to investigate the demographic characteristics, survival outcomes and prognostic factors.RESULTS: With the median follow-up of 7.1 years, the estimated 10-year OS, FFS, GFFS were 86.0%, 60.5%, and 51.2%, respectively. Matched related donors (MRD, n = 28) showed better 10-year OS than unrelated donors (n = 15) (96.4% vs. 66.7%; P = 0.006). Engraftment failure was seen in 13 patients (30.2%). Donor-type aplasia was seen in 13.8% (4/29) after fludarabine (Flu)-based conditioning (Flu-group), while in 42.6% (6/14) after cyclophosphamide (Cy)-based regimen (Cy-group) (P = 0.035). Six patients died. The 10-year OS in Cy-group was 92.9% (n = 14, all MRD), while that of Flu-group was 82.1% (n = 29; P = 0.367). But Flu-group tended to have better FFS and GFFS than Cy-group, although Flu-group had less MRDs (41.4% vs. 100%; P = 0.019), and higher proportion of previous immunosuppressive treatment (IST; 62% vs. 21.4%, P = 0.012). In MRD transplants, OS was similar between Flu-group (100%, n = 14) and Cy-group (92.9%, n = 14), while FFS (100.0% vs. 42.9%; P = 0.001) and GFFS (85.7% vs. 35.7%; P = 0.006) were significantly better in Flu-group. Stem cell sources, irradiation in the conditioning, and method of GvHD prophylaxis did not significantly influence the outcome.CONCLUSION: This study reviewed SCT outcomes for pediatric AA with changes of transplant strategies over the last 25 years. The FFS and GFFS were higher in Flu-group than in Cy-group, especially in matched related transplantation. Graft failure including donor-type aplasia remains troublesome even with Flu-based conditioning. Further refinement of transplant strategies to ensure better quality-of-life should be pursued.

Research progresses of the way to improve umbilical cord blood stem cells homing and engraftment / 中国医师杂志

Umbilical cord blood is an alternative hematopoietic stem cell source has been widely recognized.Initially,umbilical cord blood transplantation was limited,given the low engraftment.So the method of improving cord blood homing and engraftment has been widely studied in various fields.This paper briefly reviews the progress of main researches in recent years.

Matched-sibling donor versus unrelated umbilical cord blood transplantation for treating hematological malignancies in children / 中国组织工程研究

BACKGROUND: In recent years, umbilical cord blood has gradually become a crucial alternative source of stem cells for related and unrelated bone marrow or peripheral blood hematopoietic stem cell transplantation, which is increasingly used in the treatment of hematological malignancies in children. OBJECTIVE: To compare the clinical efficacy of sibling donor umbilical cord blood transplantation and unrelated umbilical cord blood transplantation for treating hematological malignancies in children. METHODS: The clinical data of children with hematological malignancies who received umbilical cord blood transplantation at the Hematopoietic Stem Cell Transplantation Center of the First Affiliated Hospital of Zhengzhou University between January 1, 1998 and December 31, 2018 was retrospectively analyzed. All the patients received myelablative conditioning regimen, and cyslosporine A combined with or without mycophenolate mofetil were concurrently adopted for graft-versus-host disease prophylaxis. RESULTS AND CONCLUSION: (1) Two patients in the sibling donor umbilical cord blood transplantation group and three in the unrelated umbilical cord blood transplantation group did not attain hematological engraftment and subsequently died from infection, and other patients succeeded in hematological engraftment. The median time of neutrophil and platelet engraftment in the sibling donor umbilical cord blood transplantation and unrelated umbilical cord blood transplantation groups was [17 days (11-43 days), 18 days (12-45 days), P=0.307] and [20.5 days (15-50 days), 27 days (18-56 days), P=0.773]. There was no significant difference between the two groups. (2) The incidence of acute graft-versus-host disease and chronic graft-versus-host disease in the sibling donor umbilical cord blood transplantation and unrelated umbilical cord blood transplantation groups was 36% vs. 43% (P=0.737) and 15% vs. 33% (P=0.412). There was no significant difference between the two groups. There was also no significant difference in the incidence of infection after transplantation between sibling donor umbilical cord blood transplantation and unrelated umbilical cord blood transplantation groups (56% vs. 71%, P=0.343). (3) There were no significant differences in the 2-year overall survival (61% vs. 36%, P=0.301), or 2-year relapse-free survival (56% vs. 33%, P=0.151). The 5-year overall survival and 5-year relapse-free survival in the sibling donor umbilical cord blood transplantation and unrelated umbilical cord blood transplantation groups were 54% vs. 24% (P=0.044) and 50% vs. 20% (P=0.039). The results showed that there was a significant difference in long-term survival rate between two groups. (4) Our results reveal that both sibling donor umbilical cord blood transplantation and unrelated umbilical cord blood transplantation are safe, effective and applicable for children with hematological malignancies. In particular, there are significant benefits in the long-term survival of substitute donor transplantation for pediatric patients with hematological malignancies.

Nutritional status of children undergoing hematopoietic stem cell transplantation and its association with post transplantation engraftment / 中华实用儿科临床杂志

Objective To assess the nutritional status of children who will receive hematopoietic stem cell transplantation,and to describe the impact of nutritional status on engraftment.Methods From December 2013 to November 2014,54 patients undergoing hematopoietic stem cell transplantation in Hematology and Oncology Center,Beijing Children's Hospital,Capital Medical University were prospectively enrolled into the study,among them 42 patients were undergoing allogeneic hematopoietic stem cell transplantation and 26 patients were suffered from peripheral blood hematopoietic stem cell transplantation.The data about nutrition were collected before preconditioning,at the 0th,30th,60th and 100th day after transplantation,and the levels were considered including weight,height,serum albumin and prealbumin.The time of engraftment was also collected,and the association between engraftment and nutritional states before transplantation was analyzed.Results (1) According to body mass index (BMI) for age,weight for age Z score which normal in ± 2 s to assess the nutritional status of patients before transplantation,the ratio of malnutrition or underweight were 3.7％ (2/54 cases) and 5.6％ (3/54 cases),and the ratio of obesity was 11.1％ (6/54 cases).The incidence of serum albumin and serum prealbumin below normal lower limit was 5.6％ (3/54 cases)and 20.4％ (11/54 cases),respectively before transplantation.And during transplantation,BMI,weight,albumin levels were obviously decreased after conditioning,and those were significantly lower than the baseline (all P ＜ 0.05).(2) The time of granulocyte engraftment and the time of platelet engraftment in patients whose serum albumin level were lower than normal below limit was (17.30 ± 5.13) days and (41.50 ± 19.09) days,while which were (12.70 ± 2.39) days and(20.90 ± 7.25) days in those patients with normal serum albumin level,and the differences were statistically significant (Z =-2.075,-1.969;P =0.031,0.022).(3) Multiple linear regression analysis showed that BMI,serum albumin,prealbumin,mononuclear cell count and CD34 + cell count had impact on engraftment in patients undergoing allogeneic hematopoietic stem cell transplantation (F =2.714,P ＜ 0.05).Conclusions Pediatric patients who will receive hematopoietic stem cell transplantation have malnutrition before transplantation and the risk of malnutrition may increase further during acute period of hematopoietic stem cell transplantation.In addition,patients with low IBM or hypoalbuminemia before transplantation may prolong the time of engraftment,so to improve the nutritional status of patients undergoing hematopoietic stem cell transplantation is in favor of engraftment.

Novel Markers of Early Neutrophilic and Monocytic Engraftment after Hematopoietic Stem Cell Transplantation

BACKGROUND: Numerous studies tried to find new markers that after hematopoietic stem cell transplantation predict engraftment earlier than the conventional marker, absolute neutrophil count (ANC >500/microL). Early engraftment prediction can be achieved by a marker that reflects the release of neutrophils and monocytes into the leukopenic peripheral blood. METHODS: We analyzed blood cell parameters, including cell population data such as volume, conductivity, and light scatter in 77 patients who underwent HSCT (allogeneic, n=63; autologous, n=11) to detect possible markers. RESULTS: We identified 2 early engraftment markers of neutrophils (NEUTRO) and monocytes (MONO); a pair of mean-volume-neutrophils (MNV) and mean-conductivity-neutrophils (MNC) for NEUTRO; and a pair of mean-volume-monocytes (MMV) and mean-conductivity-monocytes (MMC) for MONO. The new markers showed distinct patterns for early engraftment wherein 1) on the engraftment day, MNV peaked as MNC notched simultaneously for every case, and 2) MMV peaked as MMC notched simultaneously in most cases. Engraftment was predicted 3.8+/-2.7 days earlier than by ANC in 74 successful engraftment cases by using NEUTRO and/or MONO: 1) 72 cases (97.3%), in which NEUTRO and/or MONO predicted earlier engraftment than ANC, 2) 1 case, in which the 3 markers predicted engraftment on the same day, and 3) 1 case, in which NEUTRO predicted engraftment on the same day as ANC and MONO failed to predict engraftment. CONCLUSIONS: By analyzing the data from daily complete blood counts, engraftment can be predicted approximately 4 days earlier than ANC >500/microL using NEUTRO as a base marker and MONO as a supplementary marker.

Granulocyte-Derived Cationic Peptide Enhances Homing and Engraftment of Bone Marrow Stem Cells after Transplantation / 한국실험동물학회지

Current strategies to accelerate hematopoietic reconstitution after transplantation include transplantation of greater numbers of hematopoietic stem/progenitor cells (HSPCs) or ex vivo expansion of harvested HSPCs before transplant. However, the number of cells available for transplantation is usually low, and strategies to expand HSPCs and maintain equivalent engraftment capability ex vivo are limited. We noted that activated granulocyte-derived cationic peptides positively primed responsiveness of HSPCs to a CXCL12 gradient. Accordingly, we noted that accelerated homing/engraftment of beta-defensin-2, a well-known antimicrobial cationic peptide, primed bone marrow nucleated cells (BMNCs) compared to normal BMNCs after transplantation into lethally irradiated recipients. We envision that small cationic peptides, which primarily possess antimicrobial functions and are harmless to mammalian cells, could be applied to prime HSPCs before transplantation. This novel approach would be particularly important in cord blood transplantation, where the number of HSPCs available for transplantation is usually limited.

New therapeutic modalities on hematopoietic stem cell transplantation / 대한내과학회지

Hematopoietic stem cell transplantation (HSCT) has been used to treat a variety of non-malignant and malignant lymphohematopoietic disease. But, there are many obstacles in performing HSCT for patients who do not have a human leukocyte antigen (HLA)-matched donor or are not eligible for HSCT because of old age and comorbidities. A better understanding of transplantation biology led to the development of non-myeloablative stem cell transplantation, HLA-haploidentical stem cell and umbilical cord blood (UCB) transplantation. Non-myeloablative stem cell transplantation is being commonly used in older patients as well as in disorders due to their safety and therapeutic effect. For patients without a matched HLA-identical sibling or unrelated donor, other graft sources, such as UCB and HLA-haploidentical donors, have been used. Transplantation using UCB is used in child transplantation, but it is not always suitable for adult transplantation because of insufficient cell doses. Transplantation of the stem cells from HLA-haploidentical donors emerges as an alternative source for acute leukemia patients without matched donors, but it is faced with the difficulties of graft rejection, GVHD and delayed immune reconstitution. It is necessary to overcome these difficulties through further studies.

Engraftment syndrome after allogeneic hematopoietic stem cell transplantation: a case report and literature review / 白血病·淋巴瘤

Objective To study the engraftment syndrome (ES) and the possible etiology after haploidentical allognneic hematopoietic stem cell transplantation (al]o-HSCT). Methods The clinical manifestation, treatment and outcome of a chronic myeloid leukemia patient who after allo-HSCT were presented. Results The patient started to cough on day 2 after allo-HSCT, dry cough at beginning, white foam sputum, non-infectious fever, fluid retention, weight gain, transient encephalopathy on day 4. The clinical symptoms were improved after treatment with corticosteroids, in which ES was diagnosed. Conclusion ES is a series of clinical syndromes following transplantation which is different from acute graft versus host disease. It occurred after HSCT, and corticosteroids are often effective. Therefore early recognition and accurate diagnosis is very important.

Effect of ABO-incompatibility on Allogeneic Hematopoietic Stem Cell Transplantation: A Single Institute Study / 대한수혈학회지

No abstract available.

The Factors Affecting Transplanted Hepatocytes Repopulation in Rats with Liver Fibrosis

PURPOSE: Cell therapy for various diseases has gained wide acceptance. Because most patients with chronic liver failure have mild-to-severe liver cirrhosis, there are many limitations to clinical applications. We analyzed how to increase cell engraftment in rats with liver fibrosis. METHODS: We used analbuminemic SD rats (NARs) as recipients of syngeneic CAG-EGFP SD hepatocytes obtained by the 2 perfusion method. Hepatic fibrosis was induced with thioacetamide in drinking water for 6 weeks in the recipient NARs. NARs were pre-treated with gadolinium, doxorubicin, and gliotoxin before hepatocyte transplantation. We evaluated the degree of cell engraftment by RT-PCR and immunofluorescent staining for GFP and albumin. The transplanted cells were detected by immunostaining for albumin, and serum albumin was also measured. RESULTS: Although detection of GFP by RT-PCR was variable, albumin was detected in all groups 4 wks after hepatocyte transplantation. GFP and albumin were also detected by immunofluorescent staining 1 and 4 wks after cell transplantation. In control rats, albumin production was maximal at 3 wks, and after that it rapidly decreased. In the gadolinium and doxorubicin-treated group, albumin production was increased up to 4 wks. Albumin production in the gadolinium-treated group was superior to that of the doxorubicin-treated group. CONCLUSION: Kupffer cells play the most important role in cell engraftment in hepatic fibrosis. Therefore, perturbation of kupffer cells in hepatic fibrosis is needed to increase cell engraftment.

The Factors Affecting Transplanted Hepatocytes Repopulation in Rats with Liver Fibrosis

PURPOSE: Cell therapy for various diseases has gained wide acceptance. Because most patients with chronic liver failure have mild-to-severe liver cirrhosis, there are many limitations to clinical applications. We analyzed how to increase cell engraftment in rats with liver fibrosis. METHODS: We used analbuminemic SD rats (NARs) as recipients of syngeneic CAG-EGFP SD hepatocytes obtained by the 2 perfusion method. Hepatic fibrosis was induced with thioacetamide in drinking water for 6 weeks in the recipient NARs. NARs were pre-treated with gadolinium, doxorubicin, and gliotoxin before hepatocyte transplantation. We evaluated the degree of cell engraftment by RT-PCR and immunofluorescent staining for GFP and albumin. The transplanted cells were detected by immunostaining for albumin, and serum albumin was also measured. RESULTS: Although detection of GFP by RT-PCR was variable, albumin was detected in all groups 4 wks after hepatocyte transplantation. GFP and albumin were also detected by immunofluorescent staining 1 and 4 wks after cell transplantation. In control rats, albumin production was maximal at 3 wks, and after that it rapidly decreased. In the gadolinium and doxorubicin-treated group, albumin production was increased up to 4 wks. Albumin production in the gadolinium-treated group was superior to that of the doxorubicin-treated group. CONCLUSION: Kupffer cells play the most important role in cell engraftment in hepatic fibrosis. Therefore, perturbation of kupffer cells in hepatic fibrosis is needed to increase cell engraftment.

A Study of the Factors Affecting the Term of Engraftment During Hematopoietic Stem Cell Transplantation with a Focus on the Inhibitors of Oral Intake and the Period of Nutritional Support

Hematopoietic stem cell transplantation is being widely used in an attempt to treat many hematological diseases such as leukemia, anemia, and lymphoma. To evaluate the success of hematopoietic stem cell transplantation, it is very important to determine how rapidly engraftment occurs. Therefore, this retrospective study was conducted to determine which factors affected the term of engraftment during hematopoietic stem cell transplantation, while focusing on the oral intake status. To accomplish this, 416 patients who underwent transplant operations at St. Mary's hospital from May 2006 to April 2008 were evaluated. The long-term engraftment group was characterized as having longer fasting days and more frequent vomiting, diarrhea, and oral mucositis incidences than the short-term engraftment group. In addition, the inhibitors of oral intake such as vomiting, diarrhea, and oral mucositis developed frequently between the pre-transplantation and 2 weeks after transplantation. A significantly negative correlation was observed between the oral intake volume and the duration of the oral intake inhibitors. A multiple regression analysis revealed that the frequency of vomiting and oral mucositis during hematopoietic stem cell transplantation, the length of hospitalization, and the hematocrit level in the 2 weeks after hematopoietic stem cell transplantation were significant predictors of engraftment. The results of this study could be used to establish a guideline for nutritional assessment, nutritional goals, and nutritional support for patients during hematopoietic stem cell transplantation.

Engraftment of Intraperitoneally Injected Bone Marrow Cells to Newborn Mice Injected with an Angiogenesis Inhibitor

PURPOSE: Bronchopulmonary dysplasia (BPD) is characterized by arrested vascular and alveolar growth in the premature lung. Considering the consequences of arrested lung growth, the idea of administering bone marrow cells to enhance the inborn repair mechanism is promising as this may reduce the morbidity and mortality of BPD. We followed enhanced green fluorescent protein (EGFP)-labeled bone marrow cells (BMC) injected intraperitoneally into non-EGFP mice in order to determine their fate after transplantation. METHODS: An angiogenesis inhibitor, SU1498, was injected subcutaneously on day 3 in non-EGFP C57BL/6 newborn mice to create a model of arrested alveolar development. On the following day, 1x10(6) BMCs isolated from major histocompatibility complex (MHC)- matched syngenic EGFP mice were injected intraperitoneally to non-EGFP BPD mice. Morphometric analysis, immunostaining, and confocal microscopy were performed to determine the fate of EGFP-positive stem cells in the injured lung. RESULTS: SU1498 injection reduced alveolar surface area and mean alveolar volume in newborn mice. BMC injection resulted in recovery of lung structure comparable to controls. EGFP-positive BMCs were identified in the lungs of the recipient mice after intraperitoneal injection. The injected EGFP cells were co-stained with endothelial and epithelial cells of the developing lung as determined by confocal microscopy. CONCLUSION: Our results illustrated that EGFP-positive BMCs engrafted and trans- differentiated into epithelial and endothelial cells after intraperitoneal injection in a mouse model of arrested alveolar development.

Pre-engraftment Syndrome in Hematopoietic Stem Cell Transplantation

The clinical findings of fever and skin rash with or without evidence of fluid retention, which mimic engraftment syndrome, have been observed during the pre-engraftment period in patients undergoing hematopoietic stem cell transplantation. In order to characterize this newly observed clinical syndrome called pre-engraftment syndrome (pES), we retrospectively analyzed the clinical records of 50 patients. Three out of 14 patients (23.1%) who underwent cord blood stem cell transplantation developed non-infectious fever, skin rash, and tachypnea 4-15 days prior to neutrophil engraftment. Two patients spontaneously recovered with fluid restriction and oxygen inhalation. One patient died of a complicated pulmonary hemorrhage in spite of aggressive supportive therapy and steroid treatment. Four out of 23 patients (17.4%) who underwent allogeneic bone marrow transplantation developed non-infectious fever and skin rash 4 to 5 days prior to neutrophil engraftment. All four of these patients recovered with only steroid treatment. These characteristic findings were not observed in patients who had undergone autologous peripheral blood stem cell transplantation. Interestingly, the speed of neutrophil engraftment was significantly faster for the patients suffering from pre-engraftment syndrome. The close observation and further pathophysiological research are required to better understand this syndrome.

Influential Factors for Engraftment in Autologous Peripheral Hematopoietic Stem Cell Transplantation (APBSCT)

BACKGROUND: Autologous peripheral hematopoietic stem cell transplantation (APBSCT) has been widely used to treat various types of hematological disorders, metabolic diseases and congenital immunodeficiency. Hematopoietic recovery is important because prolonged duration of neutropenia and thrombocytopenia is associated with a higher risk of infection, bleeding and treatment related mortality. Many investigators have studied the factors that affect hematopoietic recovery after stem cell transplantation. METHODS: We retrospectively investigated the factors influencing hematopoietic engraftment in 112 patients with hematological malignancies and solid tumors who received APBSCT. We evaluated the gender, age, CD34+ cell number, conditioning regimens, and the type of tumor and their association with neutrophil and platelet engraftment. RESULTS: Post-transplant neutrophil engraftment (>500/microL) required a median of 11 days (range 6~50) and platelet engraftment 12 (range 1~78) days (>20,000/microL). The univariate analysis showed that the factors that positively affected hematopoietic recovery were: the type of conditioning regimens such as BEAM (BCNU, etoposide, cytosine arabinoside, melphalan) and BEAC (BCNU, etoposide, cytosine arabinoside, cyclophosphamide) versus BC (busulfan, cyclophosphamide), the CD34+ cell number and the disease diagnosis such as multiple myeloma versus acute myelogenous leukemia. The multivariate analysis showed only the CD34+ cell number (5~10 x 10(6)/kg) to be significantly associated with early neutrophil and platelet engraftment (P<.001). CONCLUSION: These findings suggest that measurement of the CD34+ cell count may be sufficient to predict the time to engraftment after APBSCT.

Cotransplantation of Cord Blood Hematopoietic Stem Cells and Culture-Expanded and GM-CSF-/SCF-Transfected Mesenchymal Stem Cells in SCID Mice

Mesenchymal stem cells (MSC) are multipotent in nature and believed to facilitate the engraftment of hematopoietic stem cells (HSC) when transplanted simultaneously in animal studies and even in human trials. In this study, we transfected culture-expanded MSC with granulocyte macrophage-colony stimulating factor (GMCSF) and stem cell factor (SCF) cytokine genes and then cotransplanted with mononuclear cells (MNC) to further promote HSC engraftment. MNC were harvested from cord blood and seeded in long-term culture for ex vivo MSC expansion. A total of 1 x 10(7) MNC plus MSC/microliter were introduced to the tail vein of nonobese diabetic/severe combined immunodeficiency mice. After 6-8 weeks later, homing and engraftment of human cells were determined by flow cytometry and fluorescence in situ hybridization studies. The total nucleated cell count and the engraftment of CD45+/CD34+ cells and XX or XY positive human cells were significantly increased in cotransplanted mice and even higher with the cytokine gene-transfected MSC (GM-CSF>SCF, p<0.05) than in transplantation of MNC alone. These results suggest that MSC transfected with hematopoietic growth factor genes are capable of enhancing the hematopoietic engraftment. Delivering genes involved in homing and cell adhesions, CXCR4 or VLA, would further increase the efficiency of stem cell transplantation in the future.

Cotransplanted Bone Marrow Derived Mesenchymal Stem Cells (MSC) Enhanced Engraftment of Hematopoietic Stem Cells in a MSC-dose Dependent Manner in NOD/SCID Mice

Transplantation of marrow-derived mesenchymal stem cells (MSCs), expanded by culture in addition to whole bone marrow, has been shown to enhance engraftment of human hematopoietic stem cells (HSCs). Our hypothesis was that there might be an optimum ratio range that could enhance engraftment. We examined the percent donor chimerism according to the ratio of HSCs to MSCs in non-obese diabetic/severe combined immunodeficiency (NOD/SCID) mice. We tested a series of ratios of co-transplanted CD34+-selected bone marrow cells, and marrow-derived MSCs into sublethally irradiated NOD/SCID mice. In all experiments, 1 x 10(5) bone marrow derived human CD34+ cells were administered to each mouse and human MSCs from different donors were infused concomitantly. We repeated the procedure three times and evaluated engraftment with flow cytometry four weeks after each transplantation. Serial ratios of HSCs to MSCs were 1:0, 1:1, 1:2 and 1:4, in the first experiment, 1:0, 1:1, 1:2, 1:4 and 1:8 in the second and 1:0, 1:1, 1:4, 1:8 and 1:16 in the third. Cotransplantation of HSCs and MSCs enhanced engraftment as the dose of MSCs increased. Our results suggest that the optimal ratio of HSCs and MSCs for cotransplantation might be in the range of 1:8-1:16; whereas, an excessive dose of MSCs might decrease engraftment efficiency.