Impact of Infusion Rate on the Early Engraftment Following Allogeneic Intra Bone Marrow Infusion of Hematopoietic Stem Cells in a Canine DLA-Identical Reduced Intensity Transplantation Model

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 5406-5406
Author(s):  
Stephanie Schaefer ◽  
Juliane Werner ◽  
Sandra Lange ◽  
Katja Neumann ◽  
Christoph Machka ◽  
...  
Keyword(s):  
Stem Cells ◽  
Bone Marrow ◽  
Hematopoietic Stem Cells ◽  
Infusion Rate ◽  
Conflicts Of Interest ◽  
Conditioning Regimen ◽  
Hematopoietic Stem ◽  
Time Points ◽  
The Impact ◽  
Reduced Intensity

Abstract Introduction: Direct intra bonemarrow (IBM) infusion of hematopoietic stem cells (HSC) is assumed to improve the homing efficiency and to accelerate the early engraftment in comparison to the conventional intravenous application of HSC. Especially for transplantation of low cell numbers i.e. "weak grafts" that is generally associated with delayed engraftment. The direct infusion of HSC in close proximity to the HSC niche by intra bone marrow transplantation (IBMT) might be a promising way. Whether the HSC infusion rate might influence the homing process and therefore the outcome after IBMT is so far unknown. Aims: Herein, we analyzed in a canine DLA-identical littermate model the impact of different graft infusion rates on the hematopoietic recovery as well as on the engraftment kinetics after IBMT following reduced intensity conditioning. Methods: Recipient dogs received IBMT following a 4.5 Gy total body irradiation (TBI). From day (d) -1 until d+35 Cyclosporin A (15mg/kg) was administered orally twice a day as immunosuppression. For IBM transfusion the graft volume was reduced by buffy coat centrifugation and dogs obtained 2x25 ml simultaneously into the humerus and femur. The infusion rate of the graft was 25ml/10 min in group 1 (IBM10, n = 8) and 25 ml/60 min in group 2 (IBM60, n = 7). A 28 day follow-up is currently available for twelve dogs (IBM10 n = 7; IBM60 n = 5). The development of the peripheral blood mononuclear cell (PBMC) and granulocyte chimerism was tested weekly. Blood count, kidney and liver enzymes were monitored routinely. Results: All animals engrafted. One dog of the IBM10 group died at d+15 (infection) and was therefore not included into analysis. The median number of infused total nucleated cells were in IBM10 4.1*108/kg (range 2.3-6.0*108/kg) and in IBM60 3.2*108/kg (range 1.8-4.4*108/kg; p=0.4). The infused CD34+ numbers were median 3.2*106/kg (range: 1.2-10.0*106/kg; IBM10) and 3.6*106/kg (range: 1.5-6.8*106/kg; IBM60; p=0.7). Time of leukocyte recovery was median d+11 after IBMT in both groups (range: d+4 to d+11, IBM10; d+8 to d+14, IBM60; p= 0.5). Median leukocytes nadirs amounted to 0.2*109/l for IBM10 and 0.3*109/l for IBM60 (p= 0.08). The median duration of leukopenia (<1*109/l) were similar (6d, range: 4-11d, IBM10; 3-9d, IBM60) (p= 0.6). Median platelet nadir was 0*109/l for both cohorts (range: 0.0-7.0*109/l, IBM10; 0.0-1.0*109/l, IBM60). The period of thrombocytopenia (≤20.0*109/l) was significantly prolonged in the IBM60 group (median 10d, range) compared to 5d (range: 3-12d) in the IBM10 group (p=0.05). Donor PBMC chimerisms at d+7, d+14 and d+28 were median 22% (range: 8-34%), 50% (range: 29-53%) and 67% (range: 47-73%) in IBM10. The results of PBMC chimerism for IBM60 were 11% (range: 5-34%), 42% (range: 20-42%) and 59% (range: 44-66%) at these time points (p = n.s.). Donor granulocyte chimerisms of median 33% (range: 11-83%), 100% (range: 58-100%) and 100% (range: 82-100%) were detected at d+7, d+14 and d+28 after HSCT in IBM10, respectively. The granulocyte chimerism in IBM60 amounted to 34% (range: 3-87%), 96% (range: 94-100%) and 98% (range: 96-100%) at the above mentioned time points p=n.s. for all time points). Conclusion: Our data suggest that early granulocyte and PBMC engraftment is not influenced by modification of the HSC infusion rate. However, the period of thrombocytopenia seems to be prolonged following a 60 minutes application. Therefore, longer infusion times in an IBMT setting seem not to be beneficial following toxicity reduced conditioning regimen. Disclosures No relevant conflicts of interest to declare.

scholarly journals Microbiota Signals Suppress the Lymphoid Specification of Hematopoietic Stem Cells

Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 204-204
Author(s):  
Joseph R. Krambs ◽  
Darlene A. Monlish ◽  
Feng Gao ◽  
Laura G. Schuettpelz ◽  
Daniel C. Link
Keyword(s):  
Stem Cells ◽  
Bone Marrow ◽  
Hematopoietic Stem Cells ◽  
Expression Profiling ◽  
Bone Marrow Cells ◽  
Conflicts Of Interest ◽  
Rna Expression ◽  
Hematopoietic Stem ◽  
Rna Expression Profiling ◽  
The Impact

Abstract Aging is associated with an expansion of phenotypic hematopoietic stem cells (HSCs) with reduced self-renewal capacity and myeloid-skewed lineage differentiation. Signals from commensal flora support basal myelopoiesis in young mice; however, their contribution to hematopoietic aging is largely unknown. Here, we characterize hematopoiesis in young and middle-aged mice housed under specific pathogen free (SPF) and germ-free (GF) conditions. We did not analyze older mice due to the difficulty in maintaining mice in a gnotobiotic facility for more than one year. Consistent with prior studies, there is a shift in hematopoiesis in aged SPF mice towards granulopoiesis, with a significant increase in the percentage of granulocytic cells and a decrease in B lineage cells in the bone marrow. The marked shift from lymphopoiesis to myelopoiesis that develops during aging of SPF mice is mostly abrogated in GF mice. Compared with aged SFP mice, there is a marked expansion of B lymphopoiesis in aged GF mice, which is evident at the earliest stages of B cell development. To investigate the impact of microbiota signals on multipotent HSPCs, we first quantified HSPCs by flow cytometry (Figure 1A-B). In aged SPF mice, the number of lineage - Sca1 + cKit + CD150 + CD48 - (LSK-SLAM) cells and CD34 - LSK-SLAM cells is increased 6.4 ± 1.7-fold and 3.4 ± 1.2-fold, respectively. Similar increases were observed in aged GF mice, with LSK-SLAM increasing 5.3 ± 1.6-fold (p=NS compared to SPF mice) and CD34 - LSK-SLAM cells increasing 2.8 ± 0.31-fold (p=NS). To quantify functional HSCs, limiting dilution transplantation experiments using unsorted bone marrow cells was performed. Although on a per cell basis the repopulating activity of aged HSCs is reduced, due to the large increase in phenotypic HSCs, the number of functional HSCs actually increases with aging, with similar increases in functional HSCs in aged SPF and GF mice (Figure 1C). Finally, to assess lineage-bias, we transplanted a limiting number of sorted HSCs and assessed lineage output. As expected, in young SPF mice, the majority of HSCs displayed a balanced myeloid/lymphoid lineage output, with a significant increase in myeloid-biased HSCs observed with aging (Figure 1D). In young GF mice, the majority of HSCs are lymphoid-biased. Moreover, although the myeloid output increased modestly with aging, the majority of HSCs in aged GF remained lymphoid-biased or balanced. Consistent with these data, RNA expression profiling of phenotypic HSCs from aged GF mice show enrichment for non-myeloid biased HSCs. Surprisingly, the RNA expression profiling data also suggest that inflammatory signaling is increased in aged GF HSCs compared with aged SPF HSCs. Collectively, these data suggest that microbiota-related signals suppress the lymphoid potential of HSCs, contributing to the expansion of myeloid-biased HSCs that occurs with aging. Figure 1 Figure 1. Disclosures No relevant conflicts of interest to declare.

The Impact of Age and Gender on Hematopoietic Stem Cells and Immune Contexture of the Bone Marrow Microenvironment

2020 ◽  
pp. 1-6
Author(s):  
Rebar N. Mohammed
Keyword(s):  
Stem Cells ◽  
Bone Marrow ◽  
Hematopoietic Stem Cells ◽  
Immune Cells ◽  
Absolute Number ◽  
Cell Number ◽  
Hematopoietic Stem ◽  
The Absolute ◽  
And Gender ◽  
The Impact

Hematopoietic stem cells (HSCs) are a rare population of cells that reside mainly in the bone marrow and are capable of generating and fulfilling the entire hematopoietic system upon differentiation. Thirty-six healthy donors, attending the HSCT center to donate their bone marrow, were categorized according to their age into child (0–12 years), adolescence (13–18 years), and adult (19–59 years) groups, and gender into male and female groups. Then, the absolute number of HSCs and mature immune cells in their harvested bone marrow was investigated. Here, we report that the absolute cell number can vary considerably based on the age of the healthy donor, and the number of both HSCs and immune cells declines with advancing age. The gender of the donor (male or female) did not have any impact on the number of the HSCs and immune cells in the bone marrow. In conclusion, since the number of HSCs plays a pivotal role in the clinical outcome of allogeneic HSC transplantations, identifying a younger donor regardless the gender is critical.

Antibody-Based Depletion of Hematopoietic Stem Cells Empties Niches for Efficient Transplantation.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. LB2-LB2
Author(s):  
Agnieszka Czechowicz ◽  
Daniel L. Kraft ◽  
Deepta Bhattacharya ◽  
Irving L. Weissman
Keyword(s):  
Stem Cells ◽  
Bone Marrow ◽  
Stem Cell ◽  
Hematopoietic Stem Cells ◽  
Conditioning Regimen ◽  
Myeloablative Conditioning ◽  
Hematopoietic Stem ◽  
Exact Function ◽  
Potential Applications ◽  
Conditioning Regimens

Abstract Hematopoietic stem cells (HSCs) are used therapeutically in bone marrow/hematopoietic stem cell transplantation (BMT/HSCT) to correct hematolymphoid abnormalities. Upon intravenous transplantation, HSCs can home to specialized bone marrow niches, self-renew and differentiate and thus generate a new, complete hematolymphoid system. Unfortunately BMT has had limited applications, due to the risks associated with the toxic conditioning regimens, such as irradiation and chemotherapy, that are deemed necessary for HSC engraftment. Elimination of these toxic conditioning regimens could expand the potential applications of BMT to include many non-malignant hematologic disorders, a wide variety of autoimmune disorders such as diabetes and multiple sclerosis, as well as in the facilitation of organ transplantation. The exact function of these traditional myeloablative conditioning regimens is not clear. To elucidate the barriers of HSC engraftment, we transplanted 50–1000 purified HSCs (Ckit+Lin−Sca1+CD34+CD150−) into immunodeficient, Rag2−/− or Rag2−/−gc−/− recipient mice and show that HSC engraftment levels rarely exceed 0.5% following transplantation without toxic conditioning, indicating that the immune system is not the only barrier to engraftment. Additionally, we did not observe a significant increase in HSC engraftment when HSC doses of >250 cells were transplanted. Even when up to 18000 HSC were transplanted, we did not see a linear increase in HSC engraftment, indicating that the increased doses of HSCs transplant inefficiently. We believe this is due to the naturally low frequency of available HSC niches, which we postulate may result from the physiologic migration of HSCs into circulation. Conversely, separation of the graft into small fractions and the subsequent time-delayed transplantation of these doses did result in increased engraftment due to the natural physiologic creation of new available HSC niches. When 1800 HSC were transplanted daily for seven days, the engraftment was 6.1-fold higher than transplantation of 12800 HSC in a single bolus. Here, we provide evidence that, aside from immune barriers, donor HSC engraftment is restricted by occupancy of appropriate niches by host HSCs. Through elimination of host HSCs we are able to increase available HSC niches for engraftment. We have developed a novel system where HSCs can be eliminated by targeting C-kit, a cell surface antigen that is highly expressed on the surface of HSCs. Cultivation of HSCs with ACK2, a depleting antibody specific for c-kit, prevented stem-cell factor (SCF) dependent HSC proliferation in vitro and resulted in cell death. Administration of ACK2 to mice led to the rapid and transient removal of >98% of endogenous HSCs in vivo thus resulting in equal numbers of available niches for engraftment. Following ACK2 clearance from serum, transplantation of these animals with donor HSCs led to chimerism levels of up to 90%, representing a 180-fold increase as compared to unconditioned animals. This non-myeloablative conditioning regimen had few side effects, other than temporary loss of coat color. The HSCs in even untransplanted animals rapidly recovered and animals remained healthy and fertile. This work redefines the way we approach BMT/HSCT, and places great emphasis on the necessity to create available HSC niches prior to transplantation. Extrapolation of these methods to humans may enable efficient yet mild conditioning regimens for transplantation, thus expanding the potential applications of BMT/HSCT.

Longitudinal Trends in Peripheral Blood Parameters Predict Development of Therapy-Related Myelodysplasia/Acute Myeloid Leukemia (t-MDS/ AML) after Autologous Transplantation for Lymphoma.

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 2133-2133
Author(s):  
Liton Francisco ◽  
Can-Lan Sun ◽  
Lester Laddaran ◽  
Melanie Sabado ◽  
Alysia Bosworth ◽  
...  
Keyword(s):  
Stem Cells ◽  
Bone Marrow ◽  
Hematopoietic Stem Cells ◽  
Hodgkin Lymphoma ◽  
Peripheral Blood ◽  
Blood Parameters ◽  
Red Cell ◽  
Hematopoietic Stem ◽  
Time Points ◽  
Over Time

Abstract t-MDS/AML is the most common cause of non-relapse mortality in patients undergoing autologous hematopoietic cell transplantation (aHCT) for Hodgkin lymphoma (HL) or non-Hodgkin lymphoma (NHL). Although t-MDS/AML is known to result from damage to hematopoietic stem cells (HSC) as a result of genotoxic cancer treatment, the sequential cellular and molecular changes leading to its development are not clearly defined. To better understand the pathogenesis of t-MDS/AML, we conducted a prospective study in 179 patients undergoing aHCT for HL (n=41) or NHL (n=138) between 1999 and 2004, who participated in a prospective longitudinal study from pre-aHCT to five years post-aHCT, with a serial collection of bone marrow and peripheral blood samples. The median length of follow-up for this cohort was 3.9 years. This report focuses on alterations in peripheral blood parameters from pre-aHCT to the development of t-MDS/AML, and compares these trends with the patients in this cohort who did not develop t-MDS/AML. A total of 22 patients have developed t-MDS/AML in this longitudinally followed cohort thus far, resulting in a cumulative incidence of 11% at 5 years. Serial evaluation of peripheral blood parameters including hematocrit, mean corpuscular volume (MCV), hemoglobin (HGB), red cell distribution width (RDW), white blood cell (WBC) count, and platelet (PLT) count, were abstracted from medical records for the following time points: pre-aHCT, day 100, 6 month, 1 year, 2 year, 3 year, 4 year and 5 year after aHCT, for a total of 1129 time points. Values of peripheral blood parameters associated with post-aHCT relapse or persistence of the primary lymphoma or from 3 months prior to development of t-MDS/AML, were excluded from analysis. As shown in the Figure, comparison of the peripheral blood parameters in subjects who developed t-MDS/AML (cases; n=22) with those who did not (controls; n=157) revealed that hematocrit values were lower for cases compared to controls at all post-aHCT time points. HGB values were lower among cases compared to controls at all post-aHCT time points. The RDW values were higher for cases compared to controls at day 100, 6 months and 1 year post-aHCT. MCV values did not differ between cases and controls at any of the time points. WBC counts for the cases were lower than controls pre-aHCT and also at all time points from 6 months post-aHCT onwards. PLT counts for cases were lower than controls at all time points pre- and post-aHCT. A fixed effect growth curve model was fitted to the data from day 100 to 5 years post-aHCT after adjusting for age at aHCT, primary diagnosis, race/ethnicity, and sex, to examine the rate of change in the peripheral blood parameters over time. Results revealed a significantly sharper decline in MCV for cases (β per 100 days = −0.43) over time as compared to controls (β =−0.15; p = 0.006). Although hematocrit increased with time for both cases and controls, the slope for the cases was significantly less steep (controls: β per 100 days=0.31 vs. cases: β per 100 days=0.12; p =0.01). In summary, we consistently observed lower values for red cell parameters, WBC, and platelets in patients with t-MDS/ AML as compared to controls across multiple timepoints post-aHCT. These differences appeared soon after HCT, were persistent, and preceded the development of t-MDS/AML. Our previous studies indicate that there is increased turnover and reduced regenerative capacity of premalignant hematopoietic stem cells at early stages of development of t-MDS/AML. The early and persistent reduction in peripheral blood parameters observed here provides further evidence that bone marrow injury and ineffective hematopoiesis long predate the development of t-MDS/AML after aHCT. Poor hematocrit recovery and enhanced decline in MCV after aHCT were independently associated with increased risk of t-MDS/AML and warrant further development as readily applied biomarkers for disease and the need for close monitoring. Figure Figure

Poly I:C Stimulates Sca-1 Expression in Murine Bone Marrow and Increases the Number of Phenotypic Hematopoietic Stem Cells.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 2504-2504
Author(s):  
Russell Garrett ◽  
Gerd Bungartz ◽  
Alevtina Domashenko ◽  
Stephen G. Emerson
Keyword(s):  
Cell Cycle ◽  
Stem Cells ◽  
Bone Marrow ◽  
Hematopoietic Stem Cells ◽  
Conflicts Of Interest ◽  
Hematopoietic Cells ◽  
Poly I:C ◽  
Hematopoietic Stem ◽  
Marrow Cells ◽  
Myeloid Progenitors

Abstract Abstract 2504 Poster Board II-481 Polyinosinic:polycytidlyic acid (poly I:C) is a synthetic double-stranded RNA used to mimic viral infections in order to study immune responses and to activate gene deletion in lox-p systems employing a Cre gene responsive to an Mx-1 promoter. Recent observations made by us and others have suggested hematopoietic stem cells, responding to either poly I:C administration or interferon directly, enter cell cycle. Twenty-two hours following a single 100mg intraperitoneal injection of poly I:C into 10-12 week old male C57Bl/6 mice, the mice were injected with a single pulse of BrdU. Two hours later, bone marrow was harvested from legs and stained for Lineage, Sca-1, ckit, CD48, IL7R, and BrdU. In two independent experiments, each with n = 4, 41 and 33% of Lin- Sca-1+ cKit+ (LSK) IL-7R- CD48- cells from poly I:C-treated mice had incorporated BrdU, compared to 7 and 10% in cells from PBS-treated mice. These data support recently published reports. Total bone marrow cellularity was reduced to 45 and 57% in the two experiments, indicating either a rapid death and/or mobilization of marrow cells. Despite this dramatic loss of hematopoietic cells from the bone marrow of poly I:C treated mice, the number of IL-7R- CD48- LSK cells increased 145 and 308% in the two independent experiments. Importantly, the level of Sca-1 expression increased dramatically in the bone marrow of poly I:C-treated mice. Both the percent of Sca-1+ cells and the expression level of Sca-1 on a per cell basis increased after twenty-four hours of poly I:C, with some cells acquiring levels of Sca-1 that are missing from control bone marrow. These data were duplicated in vitro. When total marrow cells were cultured overnight in media containing either PBS or 25mg/mL poly I:C, percent of Sca-1+ cells increased from 23.6 to 43.7%. Within the Sca-1+ fraction of poly I:C-treated cultures, 16.7% had acquired very high levels of Sca-1, compared to only 1.75% in control cultures. Quantitative RT-PCR was employed to measure a greater than 2-fold increase in the amount of Sca-1 mRNA in poly I:C-treated cultures. Whereas the numbers of LSK cells increased in vivo, CD150+/− CD48- IL-7R- Lin- Sca-1- cKit+ myeloid progenitors almost completely disappeared following poly I:C treatment, dropping to 18.59% of control marrow, a reduction that is disproportionately large compared to the overall loss of hematopoietic cells in the marrow. These cells are normally proliferative, with 77.1 and 70.53% accumulating BrdU during the 2-hour pulse in PBS and poly I:C-treated mice, respectively. Interestingly, when Sca-1 is excluded from the analysis, the percent of Lin- IL7R- CD48- cKit+ cells incorporating BrdU decreases following poly I:C treatment, in keeping with interferon's published role as a cell cycle repressor. One possible interpretation of these data is that the increased proliferation of LSK cells noted by us and others is actually the result of Sca-1 acquisition by normally proliferating Sca-1- myeloid progenitors. This new hypothesis is currently being investigated. Disclosures: No relevant conflicts of interest to declare.

Metabolic Regulation of Hematopoietic Stem Cells During Stress

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. SCI-42-SCI-42
Author(s):  
Toshio Suda
Keyword(s):  
Cell Cycle ◽  
Stem Cells ◽  
Bone Marrow ◽  
Stem Cell ◽  
Hematopoietic Stem Cells ◽  
Metabolic Regulation ◽  
Conflicts Of Interest ◽  
Hypoxia Inducible Factor ◽  
Ros Generation ◽  
Hematopoietic Stem

Abstract Abstract SCI-42 Tissue homeostasis over the life of an organism relies on both self-renewal and multipotent differentiation of stem cells. Hematopoietic stem cells (HSCs) are sustained in a specific microenvironment known as the stem cell niche. Adult HSCs are kept quiescent during the cell cycle in the endosteal niche of the bone marrow. Normal HSCs maintain intracellular hypoxia, stabilize the hypoxia-inducible factor-1a (HIF-1a) protein, and generate ATP by anaerobic metabolism. In HIF-1a deficiency, HSCs became metabolically aerobic, lost cell cycle quiescence, and finally became exhausted. An increased dose of HIF-1a protein in VHL-mutated HSCs and their progenitors induced cell cycle quiescence and accumulation of HSCs in the bone marrow (BM), which were not transplantable. This metabolic balance promotes HSC maintenance by limiting the production of reactive oxygen species (ROS), but leaves HSCs susceptible to changes in redox status (1). We have performed the metabolomic analysis in HSCs. Upregulation of pyruvate dehydrogenase kinases enhanced the glycolytic pathway, cell cycle quiescence, and stem cell capacity. Thus, HSCs directly utilize the hypoxic microenvironment to maintain their slow cell cycle by HIF-1a-dependent metabolism. Downregulation of mitochondrial metabolism might be reasonable, since it reduces ROS generation. On the other hand, at the time of BM transplantation, HSCs activate oxidative phosphorylation to acquire more ATP for proliferation. Autophagy also energizes HSCs by providing amino acids during transplantation. ATG (autophagy-related) 7 is essential for transplantation and metabolic homeostasis. The relationship between mitochondrial heat shock protein, mortalin, and metabolism in HSCs will also be discussed. Disclosures: No relevant conflicts of interest to declare.

Impact of Cytopenia Following Unmanipulated Haploidentical Hematopoietic Stem Cell Transplantation Using Post-Transplant Cyclophoshamide

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 2281-2281
Author(s):  
Villetard Ferdinand ◽  
Stefania Bramanti ◽  
Samia Harbi ◽  
Sabine Fürst ◽  
Catherine Faucher ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Cell Transplantation ◽  
Disease Risk ◽  
Conflicts Of Interest ◽  
Risk Index ◽  
Conditioning Regimen ◽  
Post Transplantation ◽  
Hematopoietic Stem ◽  
Cell Dose ◽  
The Impact

Abstract Introduction Allogeneic transplantation from a haploidentical donor (HaploSCT) is an alternative strategy in the treatment of hematologic malignancies in absence of HLA-identical donor. Recent studies reported similar outcome after HaploSCT compared to HLA-identical transplantation in different settings (Bashey, JCO 2013; Wang, Blood 2015; Gosh, JCO 2016). Although survivals seemed promising after HaploSCT, hematopoietic recovery following such a mismatched transplantation could represent a limitation. Thus, our series aims to evaluate hematological recovery after HaploSCT using a post transplantation cyclophosphamide (PT-Cy) platform. Methods This retrospective monocentric study included consecutive patients with following criteria: adults with hematological malignancies; bone marrow or peripheral blood T-replete HaploSCT from 2011 to 2015; non-myeloablative (Baltimore approach) or reduced intensity conditioning (busulfan-based) regimen; PT-Cy as part of GVHD prophylaxis. Patients with primary graft failure were excluded. Absolute neutrophil count (ANC), red cells (RCT) or platelet transfusion (PT) requirements on day 30 (D30) and day 100 (D100) were analyzed among disease-free patients. We first separately evaluated the rate of patients with significant cytopenia in each lineage (defined by ANC < 1 G/L, RCT need, PT need) and searched for impact of pre-transplantation factors on cytopenia (multivariate analyses by binary logistic regression). Then, we evaluated outcome by D30- and D100-landmark analyses according to cytopenia. Results One hundred and forty six patients with a median age of 56 years (range: 19-73) were analyzed: 142 and 117 were evaluable at D30 (4 early deaths) and D100 (17 deaths, 11 relapses), respectively. At D30, 20% of patients had ANC<1G/L, 67% needed RCT and 63% needed PT. Corresponding values at D100 were 20%, 42% and 28%, respectively (Figure 1). At D30: the use of PBSC (HR 9.5, p=0.002) was significantly associated with ANC>1G/L at D30; the use of NMAC Baltimore schema (HR 0.3, p=0.012) and CD34+ cell dose > median (HR 0.4, p=0.041) decreased PT needs while hematopoietic cell transplantation comorbidity index (HCT-CI)≥3 (HR 3.3, p=0.004) was associated with PT needs; no factor was found to significantly influence RCT. At D100: Age>60 years (HR 2.4, p=0.045), female to male HaploSCT (HR 3.3, p=0.020) and HCT-CI≥3 (HR 3.7, p=0.006) were significantly associated with higher risk of RCT need; female to male HaploSCT (HR 3.6, p=0.015) and HCT-CI≥3 (HR 6.9, p=0.001) were associated with PT needs; no factor was found to significantly influence ANC. With a median follow up of 25 months (range: 5-55), cox multivariate model with adjustment by age (continuous), disease risk index (low/intermediate vs high/very high), HCT-CI (0-2 vs ≥3), conditioning regimen (baltimore vs. busulfan-based) and graft source (bone marrow vs PBSC) showed that ANC<1 G/L was strongly associated with higher NRM (HR 2.9, p=0.011) and shorter OS (HR 3.4, p<0.001), overcoming the impact of RCT and PT needs (Figure 2A and 2B). In contrast, D100 analysis showed that PT need was the most determinant factor of increased NRM (HR 13.7, p=0.013) and poor OS (HR 7.3, p=0.003), while both D100 ANC and RCT needs did not impact outcome (Figure 2C and 2D). Discussion We found that cytopenia remain a concern after HaploSCT, leading to increased NRM and OS. The absence of ANC>1G/L at D30 as well as the need of PT at D100 may be considered as a strong post transplantation factor predicting poor outcome. Some pre-transplantation factors of cytopenia have been identified, such as CD34+ cell dose, sex mismatch and graft source. Among them, some may help for donor selection while the optimal donor for HaploSCT is still unknown. Moreover, better neutrophil recovery at D30 is achieved with the use of PBSC. CD34+ optimal cell dose in this setting remains also to be determined. In addition, post transplantation events such GVHD and/or infections should be evaluate to explore their interactions with such cytopenia, aiming to develop early therapeutic interventions. Figure 1 Figure 1. Figure 2 Figure 2. Disclosures No relevant conflicts of interest to declare.

scholarly journals Engraftment Effects of Intra Bone Marrow Compared to Intravenous Transplantation of Allogeneic Hematopoietic Stem Cells Following a Reduced Intensity Conditioning in a DLA-Identical Canine Littermate Model

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 1089-1089
Author(s):  
Juliane Werner ◽  
Stephanie Schaefer ◽  
Sandra Lange ◽  
Christoph Machka ◽  
Gudrun Knuebel ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Conflicts Of Interest ◽  
Control Group ◽  
Reduced Intensity Conditioning ◽  
Hematopoietic Stem ◽  
Platelet Recovery ◽  
Time Points ◽  
Donor Chimerism ◽  
Cell Counts ◽  
Reduced Intensity

Abstract Introduction: Successful engraftment following hematopoietic stem cell transplantation (HSCT) depends on factors like immunosuppression, graft composition and number of infused HSC. Whereas the immunosuppression as well as the type and composition of the graft are influenceable low numbers of available HSCs i.e. “weak grafts” remain a clinical challenge. Weak grafts are accompanied by increased graft failure rates and longer cytopenias associated with increased morbidity. Intra bone marrow (IBM) infusion of HSC might be an approach to overcome these problems. Studies in rodents demonstrated faster engraftment with an IBM HSCT approach compared to intravenous (IV) HSCT following myeloablative conditioning. Studies of IBM HSCT following non-myeloablative or reduced intensity conditioning (RIC) are missing. Aims: Exploring the feasibility and efficiency of IBM allogeneic HSCT in comparison to IV HSCT in dog leukocyte antigen (DLA) identical canine littermates using a RIC regimen. Methods: DLA-identical siblings were used as donor/recipient pairs for HSCT. Recipient dogs were conditioned with 4.5 Gy total body irradiation before HSCT (d0) and received 15 mg/kg Cyclosporin A BID as pre- and postgrafting immunosuppression (d-1 to d+35). BM grafts were harvested at d0. In the control group (CON, n=7) unmodified BM was transplanted IV. In the IBM group (n=7) BM harvests were centrifuged and buffy coat of the BM was then transfused simultaneously into the recipient humeri and femura (50 ml, 10 min). 10 dogs are currently evaluable. Chimerism of the peripheral blood mononuclear cells (PBMC) and granulocytes (G) were tested weekly until week 8 and afterwards in larger intervals. Blood cell counts and clinical toxicities such as weight loss were monitored. Results: Infusion of BM directly into the bone was feasible. All animals engrafted. Median number of infused total nucleated cells was 4.0*108/kg (range 2.3-6.0*108/kg, IBM) and 3.3*108/kg (range 1.9-5.0*108/kg, CON, IBM vs CON: p=0.4). Median CD34+ numbers infused were 3.1*106/kg (range:1.2-10.0*106/kg, IBM) and 3.9*106/kg (range: 1.0-7.2*106/kg, CON; IBM vs CON: p= 0.8). Hematopoietic recovery in the IBM and CON groups were similar. Leukocytes recovery (>1.0*109/l) occurred at median d+11 (range: d+10 - d+16, IBM) and d+10 (range: d+9-d+12, CON; IBM vs CON: p=0.3). Median leukocytes nadirs amounted to 0.23*109/l (IBM) and 0.28*109/l (CON; IBM vs CON: p=0.3) and median duration of leukopenia (<1.0*109/l) were 6 days (range: 5.0–11.0, IBM) and 4 days (range: 3.0–6.0, CON; IBM vs CON: p=0.1). Median platelet nadir after IBMT was 10.0*109/l (range: 0.0 - 25.0*109/l) and 6.0*109/l (range: 3.0-15.0*109/l, CON; IBM vs CON: p=0.8). Period of thrombocytopenia (≤50.0*109/l) lasted for 12 days in both groups (p=0.7). Chimerism analyses showed an early and fast increase in donor chimerism in both groups. The PBMC donor chimerism at d+14, d+28 and d+56 were 46% (range: 30-53%), 57% (range: 40-73%), 64% (range: 60-83%) for IBM. Results in CON were 37% (range: 17-93%), 60% (range: 49-100%), 57% (range: 40-100%) (IBM vs CON, p=n.s. (all time points)). The G chimerism values at that specific points were 95% (range: 53-100%), 100% (range: 53-100%), 96% (range: 88-100%) for IBM and 100% (range: 93-100%), 99% (range: 92-100%), 98% (range: 93-100%) for CON (IBM vs CON, p=n.s. (all time points)). Primary goal of the study was the feasibility of the IBM approach. Ethics regulations did not allow to use weak grafts (≤2.0*106/kg) intentionally. However, 4 animals received weak grafts (CON n=2, 1.0 and 2.0*106/kg; IBM n=2, 1.2 and 1.3 *106/kg). Of interest, comparing data of these dogs showed that durations of leukopenia were similar (median 10 days, both groups), but duration of thrombocytopenia were different (median 8 days, IBM vs 22 days, CON). Additionally, long term donor chimerism was higher in the IBM (median 80% PBMC, 100% G) vs CON (median 61% PBMC, 42% G). Conclusion: First, IBM HSCT is a feasible and effective method to deliver HSC directly into the bone marrow following RIC in a canine HSCT model. Second, our preliminary data suggest that IBM HSCT reveals advantageous engraftment differences in regards to platelet recovery and donor chimerism kinetics compared to the IV HSCT when grafts with low HSC numbers were infused. Follow up data of this study and future studies will have to clarify these observations further. Disclosures No relevant conflicts of interest to declare.

Stable Polyclonal Murine Long-Term Hematopoiesis without Clonal Exhaustion of MGMT P140K Expressing Murine Hematopoietic Stem Cells after Extended Reduced Intensity Selection.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 3271-3271
Author(s):  
Claudia R. Ball ◽  
Manfred Schmidt ◽  
Ingo H. Pilz ◽  
Fessler Sylvia ◽  
David A. Williams ◽  
...  
Keyword(s):  
Stem Cells ◽  
Gene Therapy ◽  
Bone Marrow ◽  
Hematopoietic Stem Cells ◽  
Bone Marrow Cells ◽  
Retroviral Vector ◽  
Hematopoietic Stem ◽  
Reduced Intensity ◽  
Selection Of

Abstract Gene therapy is a promising approach for the therapy of hereditary diseases, but after the occurrence of adverse side effects in a SCID-X1 gene therapy trial increased biological safety has become a major goal of gene therapy. A reduction of the number of transplanted cells could help achieve this goal by reducing the statistical likelihood of insertional mutagenesis simply by simply reducing the number of transplanted cells carrying potentially untoward insertion sites. As we have previously shown, incorporation of the selectable marker gene MGMT P140K into a retroviral vector allows a reduced intensity and toxicity in vivo selection of low numbers of genetically modified hematopoietic cells by chemotherapy with O6-benzylguanine (O6BG) and nitrosourea drugs such as 1,3-bis-2 chloroethyl-1-nitrosourea (BCNU). However, it is still not known whether extended selection over longer periods of time influences the long-term proliferation and differentiation capacity of murine haematopoietic stem cells. To address this question, serial transplantations of murine MGMT-P140K-expressing hematopoiesis combined with repeated administrations of O6-BG and BCNU were performed. After ex vivo gene transfer of a MGMT/IRES/eGFP-encoding retroviral vector, bone marrow cells were transplanted into syngeneic C57 BL/6J mice and serially transplanted. First, 2nd and 3rd generation recipient mice were subsequently treated every four weeks in order to amplify treatment effects on the long-term clonal behaviour of modified hematopoietic stem cells. Lineage contribution of transduced hematopoiesis was monitored by FACS over a total of 17 rounds of selection and clonality was monitored by LAM-PCR over a total of 16 rounds of selection. In primary mice, the percentage of transduced blood cells increased from 4.7 ± 0.8 % to 36.4 ± 9.8 % (n=12) and in secondary mice from 29.9 ± 7.2 % to 65.1 ± 8.7 % (n=18) after selection without inducing persistent peripheral blood cytopenia. Lineage analysis showed an unchanged multilineage differentiation potential in the transduced compared to control cells in 1st and 2nd generation animals. LAM PCR analysis of peripheral blood revealed stable oligo- to polyclonal hematopoiesis in 1st, 2nd and 3rd generation mice. Evidence of predominant clones or clonal exhaustion was not observed despite of up to 16 rounds of BCNU/O6-BG treatment. Interestingly, pairs of secondary transplanted mice which had received bone marrow cells from identical donors showed very similar clonal composition, engraftment kinetics under selection and lineage contribution of the transduced hematopoiesis. This is molecular proof that extensive self-renewal of transplantable stem cells had occurred in the primary mice resulting in a net symmetric refilling of the stem cell compartment. In summary, we demonstrate that even extended selection of MGMT-P140K-expressing hematopoietic stem cells by repetitive chemotherapy does not affect differentiation or proliferation potential and does not result in clonal exhaustion. Our results have important implications for the clinical use of MGMT selection strategies intending to employ amplification of a limited number of genetically modified clones in clinical gene therapy.

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