A single-step colony-forming unit assay for unseparated mobilized peripheral blood, cord blood, and bone marrow

Comparison of human umbilical cord blood processing with or without hydroxyethyl starch

BACKGROUND

Umbilical cord blood (UCB) processing with hydroxyethyl starch (HES) is the most common protocol in the cord blood banks. The quality of UCB volume reduction was guaranteed by minimum manipulation of cord blood samples in the closed system. This study aimed to analyze and compare cell recovery and viability of UCB processed using the Sepax automated system in the presence and absence of HES.

STUDY DESIGN AND METHODS

Thirty UCB bags with a total nucleated cell (TNC) count of more than 2.5 × 109 were divided in two bags with equal volume. HES solution was added to one bag and another was intact. Both bags were processed with the Sepax. To determine cell recovery, viability, and potential of colony-forming cells (CFCs), preprocessing, postprocessing, and thawing samples were analyzed.

RESULTS

The mean TNC recovery after processing and after thaw was significantly better with the HES method (p < 0.01 for the postprocessing step and p < 0.05 for the postthaw step). There were no significant differences to mononucleated cells (MNCs) and CD34+ cell recovery between the two methods after processing and after thaw. TNC and MNC viability was significantly higher without HES after processing and after thaw (p < 0.01). The results of the CFC assay were similar for both methods after processing and after thaw.

CONCLUSION

These results showed that processing of UCB using the Sepax system with the without-HES protocol due to the lower manipulation of samples could be used as an eligible protocol to reduce the volume of UCB.

The cord blood separation league table: a comparison of the major clinical grade harvesting techniques for cord blood stem cells

BACKGROUND AND OBJECTIVES

Well over 1 million Umbilical Cord Blood units (UCB) have been stored globally in the last 10 years. Already, over 20,000 transplants been performed using UCB for haematopoietic reconstitution alone, now this potential is joined by regenerative medicine. However, more needs to be known about processing of this stem cell source for it to reach full potential.

METHODS AND RESULTS

IN THIS STUDY WE EVALUATED FIVE SEPARATION METHODS: plasma depletion, density gradient, Hetastarch, a novel method known as PrepaCyte-CB and an automated centrifugal machine. Sepax gives the highest recovery of nucleated cells, an average of 78.8% (SD±21.36). When looking at CD34+ haematopoietic stem cells PrepaCyte-CB provided the greatest recovery at 74.47% (SD±8.89). For volume reduction density gradient was the most effective leaving 0.03×10(6) RBC/ml, 8 times more efficient than its nearest competitor PrepaCyte-CB (p<0.05). Finally PrepaCyte-CB processing left samples with the highest clonogenic potential after processing and more significantly after cryopreservation: 9.23 CFU/10(8) cells (SD±2.33), 1.5 fold more effective than its nearest rival Sepax (p<0.05).

CONCLUSIONS

PrepaCyte-CB was the most flexible method; the only processing type unaffected by volume. Results indicate that processing choice is important depending on your final intended use.

Evaluation of equine peripheral blood apheresis product, bone marrow, and adipose tissue as sources of mesenchymal stem cells and their differentation potential

Objective—To evaluate effects of apheresis on mesenchymal stem cells (MSCs) and compare those MSCs with MSCs obtained from adipose tissue or bone marrow (BM).

Sample Population—Samples obtained from 6 adult horses.

Procedures—Samples of blood from a peripheral vein, adipose tissue, and BM aspirate were obtained from each horse. Samples were processed via apheresis of blood and techniques reported elsewhere for adipose tissue and BM. Cultures were maintained until adherence and subsequently were subjected to differentiation protocols to evaluate adipogenic, osteoblastogenic, and chondrogenic potential.

Results—Apheresis product had a significantly higher mononuclear percentage, higher platelet count, and lower RBC count, compared with values for peripheral blood. No cell adherence to the tissue culture plates was detected for the apheresis product. Adherence was detected for 6 of 6 adipose-derived and 4 of 6 BM-derived samples. Variations in efficiency were detected for differentiation of adipose- and BM-derived cells into adipocytes, chondrocytes, and osteoblasts.

Conclusions and Clinical Relevance—Apheresis was able to concentrate mononuclear cells and reduce RBC contamination. However, the apheresis product was unable to adhere to the tissue culture plates. In matched horses, adipose- and BM-derived MSCs were capable of producing lipids, glycosaminoglycan, and mineral. The BM was vastly superior to adipose tissue as a source of MSCs with osteoblastogenic potential in matched horses. Additional studies will be necessary to optimize apheresis techniques for horses before peripheral blood can be considered a suitable source for multipotential cells for use in cell-based treatments.

Stem cell-like human endothelial progenitors show enhanced colony-forming capacity after brief sevoflurane exposure: preconditioning of angiogenic cells by volatile anesthetics

BACKGROUND

Endothelial progenitor cells play a pivotal role in tissue repair, and thus are used for cell replacement therapies in "regenerative medicine." We tested whether the anesthetic sevoflurane would modulate growth or mobilization of these angiogenic cells.

METHODS

In an in vitro model, mononuclear cells isolated from peripheral blood of healthy donors were preconditioned with sevoflurane (3 times 30 min at 2 vol% interspersed by 30 min of air). Colony-forming units were determined after 9 days in culture and compared with time-matched untreated control. Using magnetic cell sorting, CD133+/CD34+ endothelial progenitors were enriched from human umbilical cord blood, and vascular endothelial growth factor (VEGF), VEGFR2 (KDR), granulocyte colony-stimulating factor (G-CSF), STAT3, c-kit, and CXCR4 expressions were determined in sevoflurane-treated and untreated cells by real-time reverse transcriptase polymerase chain reaction. In a volunteer study with crossover design, we tested whether sevoflurane inhalation (<1 vol% end-tidal concentration) would mobilize endothelial progenitor cells from the bone marrow niche into the circulation using flow cytometry of peripheral blood samples. VEGF and G-CSF plasma levels were also measured.

RESULTS

In vitro sevoflurane exposure of mononuclear cells enhanced colony-forming capacity and increased VEGF mRNA levels in CD133+/CD34+ cord blood cells (P = 0.017). Sevoflurane inhalation in healthy volunteers did not alter the number of CD133+/CD34+ or KDR+/CD34+ endothelial progenitors in the circulation, but increased the number of colony-forming units (P = 0.034), whereas VEGF and G-CSF plasma levels remained unchanged.

CONCLUSIONS

Sevoflurane preconditioning promotes growth and proliferation of stem cell-like human endothelial progenitors. Hence, it may be used to promote perioperative vascular healing and to support cell replacement therapies.

Umbilical cord blood processing using Prepacyte-CB increases haematopoietic progenitor cell availability over conventional Hetastarch separation

BACKGROUND

Currently the most frequently used method for umbilical cord blood separation in many hospitals across the UK and the rest of the world, where small-to-medium amounts of samples are processed, is Hetastarch, a mechanical, starch-based method, which causes red cell agglutination by rouleaux formation.

AIM

In this study, a novel method (Prepa-Cyte-CB), in comparison with Hetastarch as part of an FDA-approved clinical study, was evaluated.

MATERIALS AND METHODS

Validation of data included recovery of nucleated and CD34+ cells, red blood cell reduction, colony forming unit potential, flow cytometric analysis and sterility tests.

RESULTS

PrepaCyte-CB, in comparison with Hetastarch offers fast, reliable separation with improved recovery of nucleated cells, 72.03% (+/-8.48 SD) compared to 58.09% (+/-20.06 SD), and CD34+ haematopoietic progenitor cells, 76% (+/-19.54 SD) compared to 64.19% (+/-29.77 SD). PrepaCyte-CB was also 12-fold more efficient in removing red blood cells and haemoglobin (P < 0.001) than Hetastarch.

CONCLUSIONS

These results show that PrepaCyte-CB offers superior separation of UCB when compared to Hetastarch.

Influence of volume reduction and cryopreservation methodologies on quality of thawed umbilical cord blood units for transplantation

INTRODUCTION

Although there is considerable variability in methodology among umbilical cord blood banks, their common goal is to achieve optimal product quality for transplantation. Cryopreservation is a critical issue for a long-term maintenance of cord blood viability and colony-forming capacities.

MATERIALS AND METHODS

We designed a prospective study to compare controlled (CRF) vs. non-controlled freezing (URF) of volume-reduced cord blood units. In addition, the influence of hydroxy ethyl starch (HES) on cryopreservation was also assayed. To assess the efficiency of protocols used, cell recoveries were measured and the presence of hematopoietic colony-forming units was quantified.

RESULTS

In the study phase, we observed similar CB haematopoietc recoveries for CRF and URF strategies, except for TNC recovery that was better for HES volume reduced CB units in the URF group. When we analysed the data of routine processed CB units in samples from satellite cryovials, we found better BFU-E, CFU-GM, CFU-GEMM and CFU recoveries for those units processed with HES than without HES, in an URF manner.

CONCLUSIONS

URF of CB units is a cryopreservation procedure that allows similar hematopoietic progenitor recoveries than CRF with programmed devices. However, our study suggests that those banks that cryopreserve CB units in a URF manner should use HES for volume reduction. On the other hand, for CRF cryopreservation methodology volume reduction with and without HES are equally useful.

Development of a novel assay to evaluate the functional potential of umbilical cord blood progenitors

BACKGROUND

Although the colony-forming cell (CFC) assay provides the most relevant information regarding the functional potential of progenitors in a unit of umbilical cord blood (UCB), technical challenges associated with this assay have made it difficult to standardize the assay among testing laboratories. The purpose of this study was to assess the reproducibility of a newly developed functional assay (HALO SPC-QC [HALO], HemoGenix, Inc.). This test is based on the principle that cellular proliferation responses to cytokine stimuli are proportional to intracellular ATP levels from progeny cells generated in culture from progenitors.

STUDY DESIGN AND METHODS

Results of the HALO assay were evaluated at two geographically distinct sites with matched aliquots from 12 different UCB units.

RESULTS

A significant correlation between the two sites for total nucleated cell counts was observed (r = 0.98, p < 0.001). Similarly, a strong correlation between HALO results from both sites was observed (r = 0.94, p < 0.001). Also, despite using different methods at each site for the CFC assay, results from the two sites correlated (r = 0.79, p = 0.002). A good correlation between the CFC and HALO assays (r = 0.73, p < 0.005), however, was only observed at the site with the same cytokine cocktail for both the CFC and the HALO assays.

CONCLUSION

These results support the notion that the HALO assay is a reasonable approach for measuring the functional potential of hematopoietic progenitors in UCB. Moreover, because the final readout for the HALO assay is instrument based, unlike the CFC assay, which requires a subjective enumeration of colonies, the HALO assay may be more amenable to standardization.

Automated separation of cord blood units in top and bottom bags using the Compomat G4

Cord blood (CB) has become a real alternative source of haematopoietic stem cells for bone marrow reconstitution in a variety of malignant disorders. As a response to this increasing activity, CB banks have been developed to guarantee the quality of processed CB units. Volume reduction of CB units maximizes storage space and also has other advantages. The aim of this study was to develop a program for the volume reduction of CB in the Compomat G4 device. We also compared two different top and bottom systems for CB fractionation (Compomat G4 and Optipress II). We empirically designed three different programs for volume reduction of CB with Compomat G4: two for final BC volume of 41 ml (CB1 and CB2) and the other one for buffy coat (BC) volume of 25 ml (CB3). Significantly worse recoveries were achieved for CB processed with program CB3. A RBC depletion of >or=50%, >or=60% and >or=70% were achieved for 67%, 39% and 9% of all units respectively. When comparing Compomat G4 and Optipress II, total nucleated cell recovery was similar for both methods, while lymphocytes recovery was significantly better for Optipress II.

Red blood cell depletion with a semiautomated system or hydroxyethyl starch sedimentation for routine cord blood banking: a comparative study

BACKGROUND

The major problem with long-term cord blood (CB) banking is the required storage space. In this sense, many studies have been performed to establish techniques for volume reduction of CB units.

STUDY DESIGN AND METHODS

We compared two different methods for CB volume reduction in both development and routine phases: hydroxyethyl starch (HES) sedimentation and top-and-bottom fractionation with the Optipress II (Baxter Healthcare). Monitoring the total nucleated cell (TNC) count, lymphocytes, CD34+ cells, and colony-forming unit (CFU) content in both preprocess and postprocess CB units assessed the volume reduction process.

RESULTS

The CB units processed in both groups had comparable volume and cells counts before and after volume reduction, except for number of red blood cells (RBCs), which was significantly greater for the Optipress II group. Recoveries of CD34+ and RBC depletion were significantly better for the HES group. For routine processing, TNC and lymphocyte recoveries were significantly better for CB units processed by the Optipress II system. There was, however, significantly less depletion of RBCs for this group. The time required for CB processing with the Optipress II was significantly shorter than the time needed for volume reduction by addition of HES (25+/-5 min vs. 55+/-10 min).

CONCLUSION

The volume reduction method with the Optipress II is a closed time-saving system that allows good cell recoveries. In contrast, the main advantage of the HES method is the higher RBC depletion that influences CFU content. Reducing RBC content must be the object of further improvements for volume reduction using the Optipress II method.

In vitro safety profile of G-CSF-mobilized whole blood after storage for 7 days in an infusable-grade L15 medium

BACKGROUND

G-CSF-mobilized whole blood (WB) is a cost-reducing and simple alternative for peripheral blood progenitor cell transplantation. Recently, it was demonstrated that mobilized WB supplemented with Leibovitz's L15 medium permitted prolonged preservation of clonogenic cells at ambient temperature. In this study, an infusable-grade L15 medium (IG-L15) was developed, and the safety profile of mobilized WB after 7 days of storage was investigated.

STUDY DESIGN AND METHODS

IG-L15 was manufactured in a closed system under good manufacturing practice conditions. Proinflammatory cytokine levels and hemolysis in mobilized WB were determined after 7 days of storage in different containers and were compared with current clinical mobilized WB values after 1 to 3 days of storage at 4 degrees C.

RESULTS

IG-L15 and L15 maintained clonogenic cells equally. In the samples of mobilized WB that were returned to the patient, cytokine levels were not elevated in comparison with freshly collected mobilized WB. By using IG-L15 in polystyrene-coated cell culture bags, median (range) levels of 9.4 (2.2-69.8) pg per mL (IL-1beta), 31.6 (6.1-146.5) pg per mL (TNF-alpha), 76.9 (15.5-934.9) pg per mL (IL-6), and 7195 (104-205,600) pg per mL (IL-8) were found after 7 days. Higher cytokine levels were found with L15 and different containers. He- molysis was less than 0.5 g per dL in all cases.

CONCLUSION

The storage of mobilized WB for 7 days in IG-L15 at ambient temperature is possible with adequate preservation of clonogenic cells, but cytokine levels may require plasma removal before return.