Processing of autologous bone marrow cells by apheresis technology for cell-based cardiovascular regeneration

Background aims. Bone marrow (BM)-derived mononuclear cell (MNC) preparations are increasingly used in experimental studies exploring the potential effect of progenitor cell-derived therapies in cardiocirculatory diseases. We analyzed the cellular BM composition, side-effects and other process-related variables of BM harvest and BM-MNC preparation in 80 patients with cardiovascular disease. Methods. BM (median 828 mL, range 223-1038 mL) was collected from the iliac crest. After BM harvest the MNC fraction was enriched by semi-automatic apheresis to reduce the total volume of the transplant. Autologous red blood cells (RBC) were salvaged from the initial BM harvest and autotransfused to the patients. Results. There were no serious side-effects related to BM collection, particularly no serious bleeding complications. Twenty- five of 80 (31%) patients developed mild pain. BM harvest resulted in the collection of a median of 2.8 × 10(9) MNC, containing a median of 66.5 × 10(6) CD34/45 cells, 39.5 × 10(6) CD133/45 cells and 50.3 × 10(6) CD34/CD133 cells. Apheresis technology-based MNC enrichment of harvested BM resulted in a progenitor cell recovery of 69-75.3% of total cells. Additional salvage of RBC from the initial BM harvest resulted in the recovery of a median of 175.0 mL autologous RBC mass. Transfusion of salvaged RBC was well tolerated and resulted in a significant increase in hemoglobin levels. Conclusions. Collection of BM of up to 1 L in combination with in vitro processing using a semi-automated apheresis device is a safe and feasible approach to increasing the number of progenitor cells necessary for cellular therapies, particularly when combined with RBC salvage.     

Optimizing a fully automated and closed system process for red blood cell reduction of human bone marrow products

Background aimsHematopoietic stem cell transplantation using bone marrow as the graft source is a common treatment for hematopoietic malignancies and disorders. For allogeneic transplants, processing of bone marrow requires the depletion of ABO-mismatched red blood cells (RBCs) to avoid transfusion reactions. Here the authors tested the use of an automated closed system for depleting RBCs from bone marrow and compared the results to a semi-automated platform that is more commonly used in transplant centers today. The authors found that fully automated processing using the Sepax instrument (Cytiva, Marlborough, MA, USA) resulted in depletion of RBCs and total mononuclear cell recovery that were comparable to that achieved with the COBE 2991 (Terumo BCT, Lakewood, CO, USA) semi-automated process.MethodsThe authors optimized the fully automated and closed Sepax SmartRedux (Cytiva) protocol. Three reduction folds (10×, 12× and 15×) were tested on the Sepax. Each run was compared with the standard processing performed in the authors’ center on the COBE 2991. Given that bone marrow is difficult to acquire for these purposes, the authors opted to create a surrogate that is more easily obtainable, which consisted of cryopreserved peripheral blood stem cells that were thawed and mixed with RBCs and supplemented with Plasma-Lyte A (Baxter, Deerfield, IL, USA) and 4% human serum albumin (Baxalta, Westlake Village, CA, USA). This “bone marrow-like” product was split into two starting products of approximately 600 mL, and these were loaded onto the COBE and Sepax for direct comparison testing. Samples were taken from the final products for cell counts and flow cytometry. The authors also tested a 10× Sepax reduction using human bone marrow supplemented with human liquid plasma and RBCs.ResultsRBC reduction increased as the Sepax reduction rate increased, with an average of 86.06% (range of 70.85–96.39%) in the 10×, 98.80% (range of 98.1–99.5%) in the 12× and 98.89% (range of 98.80–98.89%) in the 15×. The reduction rate on the COBE ranged an average of 69.0–93.15%. However, white blood cell (WBC) recovery decreased as the Sepax reduction rate increased, with an average of 47.65% (range of 38.9–62.35%) in the 10×, 14.56% (range of 14.34–14.78%) in the 12× and 27.97% (range of 24.7–31.23%) in the 15×. COBE WBC recovery ranged an average of 53.17–76.12%. Testing a supplemented human bone marrow sample using a 10× Sepax reduction resulted in an average RBC reduction of 84.22% (range of 84.0–84.36%) and WBC recovery of 43.37% (range of 37.48–49.26%). Flow cytometry analysis also showed that 10× Sepax reduction resulted in higher purity and better recovery of CD34+, CD3+ and CD19+ cells compared with 12× and 15× reduction. Therefore, a 10× reduction rate was selected for the Sepax process.ConclusionsThe fully automated and closed SmartRedux program on the Sepax was shown to be effective at reducing RBCs from “bone marrow-like” products and a supplemented bone marrow product using a 10× reduction rate.     

Large-scale Ficoll gradient separations using a commercially available,effectively closed,system

Background aimsMultiple cell-therapy products require density separation as a part of manufacturing. The traditional method for Ficoll separation, layering cell suspensions over Ficoll in tubes, followed by centrifugation and collection of cells from the interface, is too cumbersome and poses too high a risk of contamination for clinical-scale use. Recently, a system for clinical-scale Ficoll gradient applications has been introduced (Sepax?) but this system has limited availability and is costly.MethodsFor preparations of mononuclear cells (MNC) for dendritic cell (DC) production, we developed a Ficoll separation protocol that employs the Haemonetics? Cell Saver5? surgical blood salvage and wash instrument. This system uses standard blood bags and tubing, has single-use components, and is effectively closed. We analyzed 37 recent separation processes using this instrument and protocol. We measured depletion of red blood cells (RBC) and polymorphonuclear leukocytes (PMN), and recovery of CD14⁺ monocytes and MNC.ResultsStarting cell counts were 14.6 ± 8.0 (×10⁹). Total cell recovery was 49.2 ± 15.2%, RBC depletion was 88.4 ± 2.8%, PMN depletion was 86.9 ± 6.1%, MNC recovery was 63.6 ± 5.0% and CD14⁺ monocyte recovery was 75.3 ± 9.9%.ConclusionsThe Cell Saver5? is relatively inexpensive to purchase and use. The instrument and its disposables are licensed by the United States Food and Drug Administration (FDA) for intra-operative blood salvage, and we have obtained approval for investigational use. Our method with this instrument has proven to be simple and efficient for clinical-scale Ficoll separations.     

Effect of L-phenylalanine methyl ester on the colony formation of hematopoietic progenitor cells from human bone marrow

We have previously shown that L-phenylalanine methyl ester (PME) is capable of removing monocytes and enhancing the growth of hematopoietic colonies from human peripheral blood (PB) mononuclear cells (MNC). In the present study, we further compared the effect of PME on the colony formation of bone marrow (BM) and PB. Low density (less than or equal to 1.077 g/ml) MNC were obtained by Ficoll-diatrizoate density gradient centrifugation. Granulocyte/macrophage colony-forming units (CFU-gm) and erythroid burst-forming units (BFU-e) were cultured in agarose with conditioned media (CM) and/or interleukin 3 (IL-3), granulocyte colony-stimulating factor (G-CSF) and granulocyte/macrophage-CSF (GM-CSF). Treatment of BM MNC with 5 mM PME for 15 min at room temperature yielded a nucleated cell recovery of 44.8 +/- 5.0% (mean +/- SE; N = 8). CFU-gm were enriched 2.7-fold (range 2.0 to 4.8). Using CM or CM supplemented with G-CSF or GM-CSF has minimal effect on the enrichment. Leukocyte differentials revealed that 94.3 +/- 3.05% of the monocytes, as well as 91.2 +/- 1.60% of the cells in the neutrophilic maturation series were removed by PME. Incubation for 40 min in PME abolished CFU-gm formation. BFU-e were not enriched by the PME treatment. In contrast, 40 min incubation of PB MNC produced higher enrichment of CFU-gm than that obtained from 15 min of treatment, although lower cell recovery was obtained with the longer treatment time. In conclusion, we have demonstrated that phagocytic cells can be removed from BM or PB MNC by PME treatment.(ABSTRACT TRUNCATED AT 250 WORDS)     

Density Gradient Centrifugation Compromises Bone Marrow Mononuclear Cell Yield

Bone marrow mononuclear cells (BMNCs) are widely used in regenerative medicine, but recent data suggests that the isolation of BMNCs by commonly used Ficoll-Paque density gradient centrifugation (DGC) causes significant cell loss and influences graft function. The objective of this study was to determine in an animal study whether and how Ficoll-Paque DGC affects the yield and composition of BMNCs compared to alternative isolation methods such as adjusted Percoll DGC or immunomagnetic separation of polymorphonuclear cells (PMNs). Each isolation procedure was confounded by a significant loss of BMNCs that was maximal after Ficoll-Paque DGC, moderate after adjusted Percoll DGC and least after immunomagnetic PMN depletion (25.6±5.8%, 51.5±2.3 and 72.3±6.7% recovery of total BMNCs in lysed bone marrow). Interestingly, proportions of BMNC subpopulations resembled those of lysed bone marrow indicating symmetric BMNC loss independent from the isolation protocol. Hematopoietic stem cell (HSC) content, determined by colony-forming units for granulocytes-macrophages (CFU-GM), was significantly reduced after Ficoll-Paque DGC compared to Percoll DGC and immunomagnetic PMN depletion. Finally, in a proof-of-concept study, we successfully applied the protocol for BMNC isolation by immunodepletion to fresh human bone marrow aspirates. Our findings indicate that the common method to isolate BMNCs in both preclinical and clinical research can be considerably improved by replacing Ficoll-Paque DGC with adapted Percoll DGC, or particularly by immunodepletion of PMNs.     

Method for concentrating marrow stem cells using the IBM 2991 washer. Necessary preparation before in vitro treatment of bone marrow by pharmacologic or immunologic means

The technique using the IBM 2991 blood cell processor is an effective technique for the concentration of mononuclear cells from large volumes of bone marrow. The marrow cells are layered on to Ficoll Metrizoate using the IBM processing set. The mononuclear cells and CFU-GM recoveries are in close relationship with the hematocrit of the cell suspension processed. Twenty two bone marrows have been collected and purified according to this protocol. The mononuclear cell recovery is an average of 78,3% (range: 44-92%) and the CFU-GM recovery is in average of 67,5% (range: 40-89%). At the end of the procedure the cell viability is satisfying (97,1% +/- 1,7 are trypan blue negatives). When it is necessary to remove from the bone marrow collected either malignant cells prior autologous bone marrow graft or T lymphocytes in an attempt to prevent GVHD in allogeneic BMT, the purity of marrow cell suspension become a fundamental parameter.     

Replating of bioreactor expanded human bone marrow results in extended growth of primitive and mature cells

The capability to expand human bone marrow mononuclear cells (BM MNC) in high density perfusion culture chambers (bioreactors) has recently been developed. In these bioreactors, total cell colony-forming unit-granulocyte/macrophage (CFU-GM), and long-term culture-initiating cell (LTC-IC) numbers increase significantly over a 14-day period. However, cell growth ceases after the 14-day period, possibly due to cell density limitations. Because of the remaining presence of early cells, it should be feasible to replate the cells and obtain continued expansion. In this study, we demonstrate that bioreactors generate cells, which upon replating into secondary bioreactors, lead to continued cell, CFU-GM, and LTC-IC₈ (measured after 8 weeks of secondary culture) expansion. A two-stage protocol, involving the replating of cells on days 9 to 12 of culture into new bioreators at the original seeding density, yielded greater than 50-fold cell expansion from BM MNC in 25 days. CFU-GM were expanded inhibitory factor (LIF) had no significant effect on total cells, CFU-GM, or LTC-IC₅ in this system. We conclude that two-stage bioreactor cultures are capable of supporting extended growth of human BM MNC, CFU-GM, and LTC-IC₈. The continued expansion of these primitive cells in the second stage of culture suggests that primitive cells with significant proliferative potential were generated in this system, and previous data on LTC-IC₅ expansion has now been extended to LTC-IC₈ expansion. Further optimization of culture conditions is likely to improve on the results obtained here, thus making perfusion bioreactor culture correspondingly more attractive for expanding BM MNC for BM transplantation.     

Stem cells from peripheral blood and bone marrow: a comparative evaluation of the hemopoietic potential in the dog

The kinetics and pattern of hemopoietic recovery after supralethal total-body irradiation (TBI) were compared after transfusion of cryopreserved autografts derived from peripheral blood and bone marrow. Fractionated TBI was given in three doses of 6 Gy each at intervals of 48 h. Grafts of peripheral blood mononuclear cells (MNC) were collected by means of continuous-flow centrifugation and by using the mobilizing agent, dextran sulphate. Autografts were adjusted to contain equal numbers of committed progenitor cells (CFU-GM). Dogs grafted with blood-derived MNC (group A) and with MNC from bone marrow (group B) all received about 1 X 10(5) CFU-GM per kg body weight. In all dogs consistent hemopoietic engraftment was achieved. Comparing the pattern of regeneration of the granulocytes, group A dogs showed a significant regeneratory advantage over group B dogs, particularly during the first 20 days after transplantation. Lymphoid recovery was more rapid in group A until day 14. In both groups, blood lymphocytes remained below normal values beyond day 100. The regeneration patterns of the platelets and reticulocytes revealed no significant differences. These results are in agreement with the hypothesis that there are differences in the relationship between CFU-GM content and hemopoietic potential of autografts from different sources.     

Study of a new device for washing and concentrating cryopreserved hematopoietic stem cells and mononuclear cells: a single center experience

Background aimsCryopreserved cellular products, as parts of hematopoietic progenitor cell (HPC) transplants, mononuclear cell reinjections for donor lymphocyte infusion or extracorporeal photopheresis, can be washed before being reinjected into the patient or infused directly, depending on local practices. The aim of washing is to reduce the incidence and severity of adverse reactions (ARs) due to the dimethyl sulfoxide (DMSO) used as a cryoprotective agent and other factors, such as dead cell debris. At the authors’ cell therapy laboratory (CTL) in Poitiers, France, as in 76% of Etablissement Français du Sang (EFS) CTLs, all cryopreserved products undergo thawing in a water bath followed by washing with the COBE 2991. As this device will soon cease to be available, an alternative process needs to be assessed.MethodsThe authors compared two closed systems: the authors’ semi-automatic system using the traditional centrifugation method (COBE 2991) and an automated device using spinning membrane filtration (Lovo). A total of 72 HPC bags available for research were used. The authors first performed a paired comparison, processing one or two HPC bags washed by each device. A second study was carried out to compare two different washing solutions generally used by EFS CTLs along with variable storage conditions. Finally, the authors studied the efficiency of the Lovo with three or four thawed bags. The main parameters studied were viable CD34+ cell recovery and viability, CD3+ cell recovery, stability up to 6 h after washing, DMSO elimination and center feasibility.ResultsThe Lovo device showed better CD34+ cell recovery compared with the COBE 2991 while maintaining CD34+ viability and stability over 6 h. Moreover, Lovo efficiency seemed to be independent of the number of thawed bags processed and washing solution used in the authors’ study. CD3+ cell recovery met the authors’ internal specifications (cell recovery >50%), with similar results seen when processing with either the COBE 2991 or Lovo. Additionally, on average, 97% of DMSO was removed after washing with Lovo, minimizing the risk of ARs. The storage conditions post-processing indicated preferred storage conditions of 7 ± 3°C. Finally, if processing time seemed shorter using COBE 2991 for one bag washed, the Lovo device required only one staff member regardless of the number of HPC bags processed.ConclusionsThe Lovo device seems to provide an opportunity to standardize HPC processing, ensuring patient safety, with, on average, 97% of DMSO removed, while improving recovery of cells of interest and maintaining viability over time in case of delayed transplant. The Lovo device consequently seems to be a serious alternative to the COBE 2991.     

In vitro culture studies of granulocyte/macrophage and erythroid progenitor cells in lymphoproliferative disorders

Granulocyte/macrophage progenitor cells (CFU-GM) and erythroid progenitor cells (BFU-E) have been assayed in peripheral blood (PB) and/or bone marrow (BM) from 12 patients with acute lymphocytic leukemia (ALL), 16 patients with chronic lymphocytic leukemia (CLL) and 31 patients with various forms of non-Hodgkin lymphoma (NHL) without BM involvement. Progenitor cell growth in PB and BM from the NHL patients did not differ statistically from controls (p greater than 0.1). CFU-GM and BFU-E per ml PB were markedly increased in ALL and CLL patients (p less than 0.001) while CFU-GM and BFU-E per plated BM cells from these patients were severely depressed (p less than 0.001). Lymphoblasts from one ALL patient failed to inhibit CFU-GM and BFU-E-derived colony growth from control PB mononuclear cells. The high levels of circulating progenitor cells in ALL and CLL patients clearly distinguish them from other cytopenic hematological malignancies, in which decreased progenitor cell levels have been demonstrated previously (acute myeloid leukemia, hairy cell leukemia). The cause of this finding and its pathophysiological implication still remains to be established.     

Gastrin/cholecystokinin-like immunoreactivity in human blood cells

In the gastrin and/or cholecystokinin-like immunoreactivity (G/CCK-LI) elution patterns of blood cells in human adults, erythrocyte (RBC) elution pattern has three peaks which are coeluted with gastrin-34 (G34), gastrin-17 (G17) and V_t, and polymorphonuclear leukocyte (PMN) and mononuclear cell (MNC) elution patterns have four peaks which are coeluted with V_o, G34, G17 and V_t. The content of G/CCK-LI in RBC is 1.20±0.54 fmole/10⁸ cells (means±SD). Than in PMN and MNC is 1.44±0.67 p mole/10⁸ cells and 1.67±0.76 p mole/10⁸ cells, respectively.     

Influence of IL-1 alpha and -1 beta on the survival of human bone marrow cells responding to hematopoietic colony-stimulating factors

Purified recombinant human (rhu) IL-1 alpha and IL-1 beta were evaluated for their effects on the proliferation and survival of granulocyte-macrophage (CFU-GM) and erythroid (BFU-E) progenitor cells from normal human bone marrow (BM). Using nonadherent low density T lymphocyte depleted (NALT-) BM cells cultured in the presence or absence of IL-1, CSF-deprivation studies demonstrated that IL-1 alpha or IL-1 beta by itself did not enhance the proliferation of CFU-GM or BFU-E. They did, however, promote the survival of progenitors responding to the delayed addition of media conditioned by the 5637 cell line (5637 conditioned medium), rhu GM-CSF and erythropoietin. The survival promoting effects of IL-1 alpha on CFU-GM and BFU-E were neutralized by anti-IL-1 alpha mAb added to the cultures. The survival promoting effect of IL-1 alpha did not appear to be mediated by CSF, because neither CSF nor erythroid burst promoting activity were detectable in cultures in which NALT- cells were incubated with rhuIL-1 alpha. In addition, suboptimal concentrations of rhu macrophage CSF (CSF-1), G-CSF, GM-CSF, and IL-3, which were just below the levels that would stimulate colony formation, did not enhance progenitor cell survival. Survival of CFU-GM and BFU-E in low density (LD) bone marrow cells did not decrease as drastically as that in NALT- BM cells, and exogenously added IL-1 did not enhance progenitor cell survival of CFU-GM and BFU-E in LD BM cells. However, addition of anti-IL-1 beta decreased survival of CFU-GM and BFU-E in LD BM cells. These results implicate IL-1 in the prolonged survival of human CFU-GM and BFU-E.     

亲缘供者外周血红细胞参数对造血干细胞采集影响的经验分析

目的探讨亲缘供者外周血红细胞参数对COBE Spectra血细胞分离机的自动外周血干细胞采集程序（AutoPBSC程序）与单个核细胞采集程序（MNC程序）的影响及经验分析。 方法选取河北燕达陆道培医院2019年6月至2021年2月小红细胞亲缘供者31例45次采集为小红细胞组,选取同期非小红细胞亲缘供者51例60次采集为非小红细胞组,分别应用AutoPBSC程序和MNC程序,比较两组采集情况及采集产品相关指标。采用独立样本t检验和Mann-Whitney U检验分析2组计量资料的差异。 结果与小红细胞AutoPBSC程序组比较,小红细胞MNC程序组血小板（PLT）降低率[（25.88±15.83）﹪比（36.64±10.22）﹪]、采集效率[32.65﹪（23.60﹪,73.82﹪）比63.74﹪ （59.83﹪,68.55﹪）]、采集物体积[（158.83±34.39）比（222.91±63.9）mL]、MNC总数[（218.04±117.57）×10⁸/L比（350.24±127.64）×10⁸/L]、CD34⁺细胞总数[113.83×10⁶/L （79.25×10⁶/L,154.10×10⁶/L）比233.26×10⁶/L （177.18×10⁶/L,392.51×10⁶/L）]、MNC计数[（4.04±2.61）×10⁸/kg比（5.54±2.22）×10⁸/ kg]、CD34⁺计数[1.84×10⁶/kg （1.16×10⁶/kg,4.41×10⁶/kg）比3.64×10⁶/kg （2.49×10⁶/kg,6.37×10⁶/kg）]均升高,差异有统计学意义（P < 0.05）;与非小红细胞AutoPBSC程序组比较,非小红细胞组MNC程序组采集物体积[（162.83±51.74）比（242.56±43.25）mL]升高,差异有统计学意义（P < 0.05）。 结论对造血干细胞移植供者红细胞体积偏小时,应用MNC程序采集外周血造血干细胞,比应用AutoPBSC程序更有优势。     

A novel high-yield volume-reduction method for the cryopreservation of UC blood units

BACKGROUND: For the application of umbilical cord blood (UCB) units as hematopoietic grafts, a dose of 3.7 x 10(7) nucleated cells (NC)/kg body weight is required. NC can be lost during volume-reduction processing and during thawing. A novel modification of the double-processing protocol with the aim of minimizing NC loss is described and evaluated. METHODS: One-hundred and fifty UCB were collected. The volume was reduced by a centrifugation step following double-processing in the presence of 2% HES 200/0.5. Pre- and post-processing cell counts and platelet parameters were measured with an automatic counter. The number of viable CD34+ hemopoietic stem cells was measured by flow cytometry. In 25 of the samples, colony-forming units (CFU) were also determined. The same samples were thawed 6 months after cryopreservation and re-evaluated. RESULTS: The volume was reduced to 6 +/- 1.5 mL. The recovery of NC, MNC, CD34+ hemopoietic stem cells, RBC depletion and CFU following double-processing was 93.6 +/- 3.2%, 95.8 +/- 2.2%, 98.4 +/- 1.5%, 96.8 +/- 1.1% and 107.1 +/- 6.1% (for 25 samples), respectively. The post-thaw recoveries of NC, MNC, CD34+ hemopoietic stem cells and CFU (for 25 samples) were 78.6 +/- 5.4%, 90.8 +/- 4.4%, 96.4 +/- 2.5%, 89.1 +/- 4.1%, respectively. No post-thaw cell aggregation was observed. A significant (P<0.05) post-thaw loss of platelets and signs of platelet activation was observed. DISCUSSION: The protocol uses non-expensive equipment and clinically approved materials and results in samples that can be used in patients with a mean weight of 32.7 kg.     

To stay or to leave: Stem cells and progenitor cells navigating the S1P gradient

Most hematopoietic stem progenitor cells (HSPCs) reside in bone marrow (BM), but a small amount of HSPCs have been found to circulate between BM and tissues through blood and lymph. Several lines of evidence suggest that sphingosine-1-phosphate (S1P) gradient triggers HSPC egression to blood circulation after mobilization from BM stem cell niches. Stem cells also visit certain tissues. After a temporary 36 h short stay in local tissues, HSPCs go to lymph in response to S1P gradient between lymph and tissue and eventually enter the blood circulation. S1P also has a role in the guidance of the primitive HSPCs homing to BM in vivo, as S1P analogue FTY720 treatment can improve HSPC BM homing and engraftment. In stress conditions, various stem cells or progenitor cells can be attracted to local injured tissues and participate in local tissue cell differentiation and tissue rebuilding through modulation the expression level of S1P1, S1P2 or S1P3 receptors. Hence, S1P is important for stem cells circulation in blood system to accomplish its role in body surveillance and injury recovery.     

Environmentally dependent erythrocyte membrane permeability as a source of error in the determination of hematocrit]

The volume of human red blood cells (RBC) was evaluated by means of the centrifugation method (hematocrit) and 131-J-labelled human serum albumin, respectively. Both of the methods yielded an identical volume of about 107 micron3 of the single RBC, provided the evaluation was performed in autologous plasma. Contrary to the 131-J-albumin method the results of which were found independent of various pretreatments of RBC, the centrifugation hematocrits of RBC previously washed with PBS and resuspended in PBS or saline protein media resulted in a mean cell volume of about 86 micron3. The decrease of the cell volume was associated with an efflux of K+ ions. If the RBC are centrifuged at 800 g instead of 15000 g, their volume will remain unchanged. The assessment of cytodeformability has shown, that RBC in PBS by loss of cell volume could enter a 2.3 micron micropipette completely. RBC in plasma, though traversing a 2.9 micron micropipette were incapable of entering a 2.3 micron channel completely. With pressures ranging from 300 to 350 mm H2O the processes of these cells undergo microspherulation.     

Stimulation of in vitro hematopoiesis by a murine fetal hepatocyte clone through cell—cell contact

We have previously shown that a fetal liver-derived epithelial cell clone, FHC-4D2, could support hematopoiesis in vitro through its colony-stimulating factor (CSF) activities in a short-term culture. In this study, since FHC-4D2 cells were found capable of maintaining hematopoietic progenitors in the coculture for a long time, we examined how FHC-4D2 could exert hematopoietic supporting activity in a long-term culture by coculturing adult bone marrow (BM) cells or fetal liver (FL) cells on a monolayer of FHC-4D2 cells. This clone could maintain the colony-forming unit of granulocytes and macrophages (CFU-GM) of BM for ≥ 12 weeks under the coculture condition, but the fibroblastic cell clone from the fetal liver, FHC-4A3, could not support the survival of CFU-GM, even for 1 week. In addition to BM CFU-GM, the FHC-4D2 clone also supported the survival of FL CFU-GM, burst-forming unit of erythroid cells (BFUe), and colony-forming unit of mixed progenitors (CFU-Mix) for longer than 4 weeks. When BM cells were separated by a membrane filter from the FHC-4D2 cells in the coculture, the comparable number of CFU-GM was maintained at day 3, but virtually no hematopoietic progenitors were detected at the end of the first week. CFU-GM were present in both nonadherent and adherent cells to the FHC-4D2 cells at day 3 of the coculture, but at day 7, the adherent population contained greater number of CFU-GM. CFU-GM derived from the adherent cells formed larger colonies and contained more bipotential CFU-GM than the nonadherent population. When BM cells from mice given 5-fluorouracil were cocultured with FHC-4D2 cells under the limiting dilution condition, interleukin-3 (IL-3)-responsive CFU-GM were induced from immature hematopoietic progenitor cells that were otherwise unresponsive to IL-3. From these data we conclude that the FHC-4D2 clone could generate and maintain IL-3-responsive hematopoietic progenitors via close contact and that, in the fetal liver, the contact between hepatocytes and hematopoietic cells may be critically important in inducing the differentiation of resting, IL-3-unresponsive immature hematopoietic cells into CFU-GM (progenitors responsive to IL-3) and in triggering the self-renewal of CFU-GM. © 1994 Wiley-Liss, Inc.     

不同降温速率对脐血干细胞冷冻复苏后生物学特性的影响

考察了不同降温速率对脐血造血干细胞各种生物学特性的影响。在4℃～-40℃的降温范围内,分别选择-0.5℃/min, -1℃/min, -5℃/min的降温速率进行降温,对复苏后的脐血单个核细胞的回收率、活性和CD34+含量的变化以及BFU-E、CFUGM和CFU-MK集落的回收率进行了考察,发现在-1℃/min的降温速率下,脐血MNC回收率可达93.3%±1.8%,活性可达95.0%±3.9%, CD34^＋细胞回收率达80.0%±17.9%,BFUE回收率为87.1%±5.5%,CFUGM回收率达88.5%±8.9%,CFUMK的回收率也达到86.2%±7.4%。并且对复苏后的细胞进一步进行体外培养,发现在-1℃/min的降温速率下复苏的细胞仍然具有与未经冷冻细胞相似的扩增能力,而-0.5℃/min和-5℃/min这两种降温速率条件下复苏的细胞与未经冷冻的细胞相比差距较大。因而-1℃/min的降温速率对冻存脐血干细胞比较合适。     

The role of the neutrophil and formed elements of the blood in an in vitro model of reperfusion injury

Using The globally ischaemic isolated guinea-pig heart we conducted studies to assess the role of activated neutrophils (PMNs) and the role of the endothelium in reperfusion injury. Reperfusion injury was induced by a 20 min period of global ischaemia followed by a 30 min reperfusion with Krebs' buffer supplemented with f-Met-Leu-Phe (fMLP) and heparinized blood. Ischaemia alone or blood alone resulted in a complete recovery in contractile function measured by developed pressure, fMLP (500 muM) and blood, administered to normoxic hearts did not affect contractile function. The combination of 100 muM fMLP and blood beginning at reperfusion and continuing for 30 min decreased the recovery in contractile function (max. 33 +/- 6% reovery) while buffer and 100 pM fMLP resulted in a complete recovery in function. In hearts infused with buffer and neutropenic blood incubated with 100 muM fMLP a complete recovery in function was observed. Isolated peritoneal neutrophils, 7-70 x 10(5) PMN/ min, incubated with 100 muM fMLP and Krebs' solution decreased contractile function in a concentration-related manner (max. 44 +/- 11% recovery). Platelets, plasma or red blood cells alone incubated with fMLP did not decrease recovery in developed pressure. Platelets and PMN incubated with 100 muM fMLP did not, while red blood cells and PMN did, elicit a reduction in recovery in contractile function (34 +/- 4% recovery). A 20 min period of global ischaemia destroys the functional integrity of the endothelium (response to Ach). Pre-treatment of the heart with sufficient H(2)O(2) to functionally damage the endothelium, followed by infusion of Krebs' solution supplemented with blood and 100 muM fMLP also elicited a reduction in recovery of contractile function (42 +/- 15% recovery). In summary, partially activated neutrophils play a major role in reperfusion injury and there exists a cooperativity between the RBC and PMN in this model.