Associations among nucleated cell, CD34+ cell and colony-forming cell contents in cord blood units obtained through a standardized banking process

Umbilical cord blood quality and quantity: Collection up to transplantation

Umbilical cord blood (UCB) is an attractive source of hematopoietic stem cells for transplantation in some blood disorders. One of the major factors that influence on transplantation fate is cord blood (CB) cell count, in addition to human leukocyte antigen similarity and CD34+ cell number. Here, we review the factors that could effect on quality and quantity of CBUs. Relevant English-language literatures were searched and retrieved from PubMed using the terms: CB, quality, collection, and transplantation. The numbers of total nucleated cells (TNCs) and CD34+ cells are good indicators of CB quality because they have been associated with engraftment; thereby, whatever the TNCs in a CB unit (CBU) are higher, more likely they led to successful engraftment. Many factors influence the quantity and quality of UCB units that collect after delivery. Some parameters are not in our hands, such as maternal and infant factors, and hence, we cannot change these. However, some other factors are in our authority, such as mode of collection, type and amount of anticoagulant, and time and temperature during collection to postthaw CBUs and freeze-and-thaw procedures. By optimizing the CB collection, we can improve the quantity and quality of UCB for storage and increase the likelihood of its use for transplantation.

Associated factors of umbilical cord blood collection quality

After 30 years of hematopoietic stem cell use for various indications, umbilical cord blood is considered as an established source of cells with marrow and postmobilization peripheral blood. The limited number of cells still remains a problematic element restricting their use, especially in adults who require to be grafted with a higher cell number. Improving the quality of harvested cord blood, at least in terms of volume and amount of cells, is essential to decrease the number of discarded units. In this review, we examine several variables related to parturient, pregnancy, labor, delivery, collection, the newborn, umbilical cord, and placenta. We aim to understand the biologic mechanisms that can impact cord blood quality. This knowledge will ultimately allow targeting donors, which could provide a rich graft and improve the efficiency of the collection.

Optimizing cord blood collections: Assessing the role of maternal and neonatal factors

BACKGROUND

As processing and cryopreservation of cord blood is time consuming and costly, it is essential to select units with optimal CD34+ cells, total nucleated cell (TNC) number and colony forming units (CFUs). These are the most important factors affecting outcome of UCB transplantation and are influenced by various maternal and neonatal factors.

AIM AND OBJECTIVES

To determine the maternal and neonatal factors affecting TNC and CD34+ cell counts in cord blood so as to aid in proper selection of cord blood units for cryopreservation.

MATERIALS AND METHODS

A total of 100 UCB units were collected from normal vaginal deliveries, processed and assessed for volume, TNC, CD34+ cell count and CFU-GM. These parameters were then analyzed to find out whether they correlated with maternal and neonatal characteristics such as mother's age, parity, gestational age, baby's birth weight, and sex.

RESULTS

The volume of CB collected significantly correlated with the TNC, CD34+ cell, and CFU-GM yields (P < 0.02). A heavier placenta (P < 0.05), and a heavier baby (P < 0.002) were associated with a significantly greater volume of CB whereas the age, parity of mother and the sex of the baby had no significant effect.

CONCLUSION

The only factors found to affect the TNC and CD34+ cell counts significantly were weight of the baby and placenta and the volume of cord blood collected. Since these factors are of prognostic significance, their analysis will aid in deciding which UCB unit should be processed and cryopreserved for UCB banking and subsequent transplantation.

Improving Quality and Potency Testing for Umbilical Cord Blood: A New Perspective

This article critically reviews current methods to test and characterize umbilical cord blood (UCB) for hematopoietic stem cell transplantation. These tests include total nucleated cell (TNC) count, viability, viable CD34-positive content, and the colony-forming unit assay. It is assumed that the data obtained are sufficient to perform a UCB stem cell transplant without actually determining the quality and potency of the stem cells responsible for engraftment. This assumption has led not only to a high graft failure rate attributed to low or lack of potency, but also to noncompliance with present statutes that require UCB stem cells to be of high quality and, indeed, potency for a transplant to be successful. New evidence now calls into question the quality of the data, based on the UCB processed TNC fraction because using this impure fraction masks and significantly underestimates the functionality of the stem cells in both the segment and the unit. It is proposed that UCB units should be processed to the mononuclear cell fraction and that new cost-effective technology that measures the quality and potency of UCB stem cells be implemented to achieve better practices in UCB testing. These changes would provide the transplant physician with the assurance that the stem cells will perform as intended and would reduce risk and increase safety and efficacy for the patient.

SIGNIFICANCE

Current stem cell transplantation of umbilical cord blood cells requires testing that includes four basic parameters that do not determine whether the stem cells are of high quality, as required by the Stem Cell Therapeutic and Research Act of 2005. No cord blood units collected or transplanted so far have been tested for stem cell quality or potency. New scientific evidence calls into question cord blood processing and testing practices required by regulatory agencies and standards organizations. A new perspective is described that includes stem cell quality and potency testing that could reduce graft failure rates.

Optimal method for collection of umbilical cord blood: an Egyptian trial for a public cord blood bank

BACKGROUND

Umbilical cord blood (UCB) contains stem cells and can be used as an alternative to bone marrow transplantation. Engraftment is dependent on the total nucleated cell (TNC) and CD34+ cell counts of the cord blood units. This study was designed to evaluate the effect of the method of collection of the UCB on the yield of the cord blood units.

STUDY DESIGN AND METHODS

Informed consent was obtained from 100 eligible mothers for donation of cord blood. Both in utero and ex utero methods were used for collection. The cord blood volume was measured. The TNC and the CD34+ cell counts were enumerated.

RESULTS

We have found that in utero collection gave significantly larger volumes of cord blood and higher TNC counts than ex utero collection. There was no significant difference between both methods regarding the CD34+ cell counts. This study revealed a significant correlation between the volume of the collected cord blood and both TNC and CD34+ cell counts.

CONCLUSION

It is better to collect cord blood in utero before placental delivery to optimize the quality of the cord blood unit.

Detecting primitive hematopoietic stem cells in total nucleated and mononuclear cell fractions from umbilical cord blood segments and units

BACKGROUND

Rare hematopoietic stem cell populations are responsible for the transplantation engraftment process. Umbilical cord blood (UCB) is usually processed to the total nucleated cell (TNC), but not to the mononuclear cell (MNC) fraction. TNC counts are used to determine UCB unit storage, release for transplantation and correlation with time to engraftment. However, the TNC fraction contains varying concentrations of red blood cells, granulocytes, platelets and other cells that dilute and mask the stem cells from being detected. This does not allow the quality and potency of the stem cells to be reliably measured.

METHODS

63 UCB segments and 10 UCB units plus segments were analyzed for the response of both primitive lympho-hematopoietic and primitive hematopoietic stem cells in both the TNC and MNC fractions. The samples were analyzed using a highly sensitive, standardized and validated adenosine triphosphate (ATP) bioluminescence stem cell proliferation assay verified against the colony-forming unit (CFU) assay. Dye exclusion and metabolic viability were also determined.

RESULTS

Regardless of whether the cells were derived from a segment or unit, the TNC fraction always produced a significantly lower and more variable stem cell response than that derived from the MNC fraction. Routine dye exclusion cell viability did not correspond with metabolic viability and stem cell response. Paired UCB segments produced highly variable results, and the UCB segment did not produce similar results to the unit.

DISCUSSION

The TNC fraction underestimates the ability and capacity of the stem cells in both the UCB segment and unit and therefore provides an erroneous interpretation of the of the results. Dye exclusion viability can result in false positive values, when in fact the stem cells may be dead or incapable of proliferation. The difference in response between the segment and unit calls into question the ability to use the segment as a representative sample of the UCB unit. It is apparent that present UCB processing and testing methods are inadequate to properly determine the quality and potency of the unit for release and use in a patient.

Hematopoietic stem and progenitor cell harvesting: technical advances and clinical utility

Hematopoietic stem and progenitor cell (HSPC) transplantations require prior harvesting of allogeneic or autologous HSPCs. HSPCs are usually present in bone marrow (BM) during the entire life, in cord blood (CB) at birth, or in peripheral blood (PB) under particular circumstances. HSPCs were first harvested in BM and later in CB and PB, as studies showed interesting features of such grafts. All harvesting methods were in use throughout the years, except BM harvesting for HSPC autologous transplantation, which was replaced by PB harvesting. BM, CB, and PB harvesting methods have been developed, and materials and devices technically improved to increase the number of HSPCs harvested. In parallel, knowing the features of the donors or patients associated with successful numbers of HSPCs allows the adaptation of appropriate harvesting methods. Moreover, it is important to ensure the safety of donors or patients while harvesting. This review describes the methods used for harvesting based on recent studies or developments around these methods, and more particularly, the means developed to increase the numbers of HSPCs harvested in each method. It also explains briefly the influence of technical improvements in HSPC harvesting on potential changes in HSPC graft composition.

Neonatal sex and weight influence CD34(+) cell concentration in umbilical cord blood but not stromal cell-derived factor 1-3'A polymorphism

BACKGROUND

Umbilical cord blood (UCB) has been used as an alternative source of donor hematopoietic stem cells for hematologic transplant setting over the past decade. This study attempted to evaluate potential predictors of cord blood quality.

METHODS

A total of 750 UCB samples were studied (male, n = 365; female, n = 385). The impact of neonatal sex, weight and stromal cell-derived factor-1α polymorphism on the quality of these UCB samples was investigated.

RESULTS

Male neonatal UCB was significantly richer in CD34(+) cells than was female UCB (P < 0.001), whereas female UCB was richer in total nucleated cells (P = 0.01). There was a slight correlation between CD34(+) cells concentration and UCB sample weight (P < 0.01) that could be attributed to the higher weight of male neonates. The use of tetra-polymerase chain reaction to detect stromal cell-derived factor-1α polymorphisms in 180 neonates revealed no differences between A/A, G/G and A/G allelic combinations.

CONCLUSIONS

These data emphasize the lack of predictive factors for CD34(+) cells and total nucleated cell concentrations in UCB samples before processing.

Cord blood banking activity in Iran National Cord Blood Bank: a two years experience

Today umbilical cord blood (UCB) has known as a commonly used source of hematopoietic stem cells for allogeneic transplantation and many cord blood banks have been established around the world for collection and cryopreservation of cord blood units. Herein, we describe our experience at Iran National Cord Blood Bank (INCBB) during 2 years of activity. From November 2010 to 2012, UCBs were collected from 5 hospitals in Tehran. All the collection, processing, testing, cryopreservation and storage procedures were done according to standard operation procedures. Total nucleated cells (TNC) count, viability test, CD34+ cell count, colony forming unit (CFU) assay, screening tests and HLA typing were done on all banked units. Within 3770 collected units, only 32.9% fulfilled banking criteria. The mean volume of units was 105.2 ml and after volume reduction the mean of TNC, viability, CD34+ cells and CFUs was 10.76×10(8), 95.2%, 2.99×10(6) and 7.1×10(5), respectively. One unit was transplanted at Dec 2012 to a 5-year old patient with five of six HLA compatibilities. In our country banking of UCB is new and high rate of hematopoietic stem cell transplants needs expanding CB banks capacity to find more matching units, optimization of methods and sharing experiences to improve biological characterization of units.

Growth of erythroid cells from thawed unseparated cord blood in vitro without exogenous erythropoietin

INTRODUCTION

Previous erythroid cell cultures have depended on added serum or erythropoietin. In this paper, the growth of erythroid cells from thawed unseparated cord blood units in vitro without serum or exogenous erythropoietin is reported.

METHODS

Thawed volume-reduced cord blood was cultured in conditions designed to support the megakaryocytic lineage, with thrombopoietin and interleukins 3 and 6. Erythroid cells were detected with glycophorin A (GlyA), CD71, and benzidine (flow cytometry and immunocytochemistry).

RESULTS

Nucleated and anucleated GlyA-positive, as well as benzidine-positive cells were observed from day 9. In flow cytometry, at days 0 and 9, 5.9% and 14% of all events were GlyA+, and 14% and 53% were CD71+, respectively. At days 0 and 9, 4.5% and 12% of the events were double-positive for GlyA and CD71, respectively. By day 14, the percentages of GlyA+, CD71+ and double-positive events had started to decrease (9.7%, 35%, and 5.3%, respectively).

CONCLUSIONS

Erythroid cells were generated from thawed unseparated cord blood units without exogenous erythropoietin. Thawed cord blood possesses the potential for erythroid growth in vitro in a culture medium designed for other cell types.

Associations among birth weight, placental weight, gestational period and product quality indicators of umbilical cord blood units

INTRODUCTION

Numbers of CD34+ cell and total nucleated cell (TNC) and cord blood volume are commonly used as indicators for haematopoietic potential of umbilical cord blood (UCB) units. The purpose of this study was to investigate the relationship between donor-related factors and the quality indicators of UCB.

METHODS

Obstetric and neonatal clinical laboratory data of a total of 1549 UCB units were obtained from Buddhist Tzu Chi Stem Cells Center (BTCSCC) Cord Blood Bank. A retrospective multivariate analysis was conducted to analyze the data.

RESULTS

Our results showed that birth weight had positive correlations with each of the clinical features of CD34+ cell number, TNC count and unit volume of UCB, followed by the placental weight. Longer gestational period would decrease CD34+ cell number and volume of UCB. Female baby and mode of vaginal delivery of neonates were found to have larger amount of TNC in UCB.

CONCLUSION

Our results would be helpful and beneficial in building up standard criteria for evaluating stored UCB units.

Ex-vivo expansion of red blood cells: how real for transfusion in humans?

Blood transfusion is indispensable for modern medicine. In developed countries, the blood supply is adequate and safe but blood for alloimmunized patients is often unavailable. Concerns are increasing that donations may become inadequate in the future as the population ages prompting a search for alternative transfusion products. Improvements in culture conditions and proof-of-principle studies in animal models have suggested that ex-vivo expanded red cells may represent such a product. Compared to other cell therapies transfusion poses the unique challenge of requiring great cell doses (2.5×10(12) cells vs 10(7) cells). Although production of such cell numbers is theoretically possible, current technologies generate red cells in numbers sufficient only for safety studies. It is conceived that by the time these studies will be completed, technical barriers to mass cell production will have been eliminated making transfusion with ex-vivo generated red cells a reality.

Association of cord blood platelet count and volume with hemoglobin in healthy term infants

OBJECTIVE

The aim of this study was to investigate relationships of cord blood cells in healthy term infants both from vaginal and Cesarean sections.

STUDY DESIGN

The study sample comprised 167 consecutive cord blood collections accepted for processing in an accredited cord blood bank. The effect of varying anticoagulant-to-blood ratio was excluded by standardizing the cell concentrations to reflect the values in native blood. Statistical analysis included descriptive statistics, simple linear regression analysis, Mann-Whitney U-test, cumulative frequency plots and Smirnov two-sample test.

RESULT

As expected, hemoglobin correlated with red blood cell concentration. Interestingly, mean platelet volume was associated with hemoglobin, red blood cell concentration and hematocrit. The platelet count was inversely associated with the parameters.

CONCLUSION

The observed associations of cord blood hemoglobin with mean platelet volume and platelet count reflect the physiology of fetal hematopoiesis at term.

Lentiviral-mediated genetic correction of hematopoietic and mesenchymal progenitor cells from Fanconi anemia patients

Previous clinical trials based on the genetic correction of purified CD34(+) cells with gamma-retroviral vectors have demonstrated clinical efficacy in different monogenic diseases, including X-linked severe combined immunodeficiency, adenosine deaminase deficient severe combined immunodeficiency and chronic granulomatous disease. Similar protocols, however, failed to engraft Fanconi anemia (FA) patients with genetically corrected cells. In this study, we first aimed to correlate the hematological status of 27 FA patients with CD34(+) cell values determined in their bone marrow (BM). Strikingly, no correlation between these parameters was observed, although good correlations were obtained when numbers of colony-forming cells (CFCs) were considered. Based on these results, and because purified FA CD34(+) cells might have suboptimal repopulating properties, we investigated the possibility of genetically correcting unselected BM samples from FA patients. Our data show that the lentiviral transduction of unselected FA BM cells mediates an efficient phenotypic correction of hematopoietic progenitor cells and also of CD34(-) mesenchymal stromal cells (MSCs), with a reported role in hematopoietic engraftment. Our results suggest that gene therapy protocols appropriate for the treatment of different monogenic diseases may not be adequate for stem cell diseases like FA. We propose a new approach for the gene therapy of FA based on the rapid transduction of unselected hematopoietic grafts with lentiviral vectors (LVs).

Ten-year quality control of a semiautomated procedure of cord blood unit volume reduction

BACKGROUND

Volume reduction of cord blood units decreases the cost of cryogenic storage. This study reports the analysis of a 10-year quality control program of a semiautomated cord blood volume reduction procedure.

STUDY DESIGN AND METHODS

Cord blood was collected in a plastic bag containing 29 mL citrate-phosphate-dextrose, centrifuged at 2124 x g for 12 minutes, and processed with a semiautomated device. The procedure was aimed at removing most red blood cells and plasma and concentrating hematopoietic progenitors in the buffy coat (BC), thus reducing the unit volume and saving cryogenic space. Finally, the BC was cryopreserved with an equal volume of 20 percent dimethyl sulfoxide. Total nucleated cells (TNCs) were counted before and after processing in the 4311 units banked from 1998 through 2007, whereas CD34+ cells and colony-forming units-granulocyte-macrophage (CFU-GM) were counted in 420 random units from 2001 through 2007.

RESULTS

Mean postvolume reduction annual recoveries of TNCs, CD34+ cells, and CFU-GM ranged from 82.8 +/- 12.3 (standard deviation) to 91.4 +/- 6.4 percent, from 87.8 +/- 14.1 to 95.2 +/- 23.8 percent, and from 101.5 +/- 51.4 to 117.8 +/- 59.5 percent, respectively. Very strong correlations were found (r > 0.87) between postprocessing versus preprocessing TNCs, CD34+ cells, and CFU-GM; a moderate correlation between initial TNC count and unit's volume (r = 0.51); and no correlation between TNC percentage of recovery in the BC and initial unit's volume. The latter data indicate that most TNCs concentrate in the BC.

CONCLUSIONS

The semiautomated procedure of cord blood unit volume reduction used in this study provides high and stable cellular recoveries during several years of routine cord blood banking.

Association of cord blood platelet characteristics and hematopoietic progenitor cells

BACKGROUND

Total nucleated cell (TNC) dose is associated with neutrophil and platelet (PLT) engraftment after cord blood (CB) transplantation and thus is used for selection of CB for banking. The goal of this study was to evaluate the internal relationships of CB PLT characteristics, TNC, and the hematopoietic progenitor cell (HPC) content of CB units.

STUDY DESIGN AND METHODS

HPC and TNC counts of 167 CB units processed with an automated cell separation system were compared with CB PLT count and mean PLT volume (MPV). Megakaryocyte progenitors (CFU-MK) were cultured from a subset of units (n = 24).

RESULTS

PLT concentration correlated with MPV (r = -0.39), which was also associated with both TNC and total CD34+ cells before and after processing (r = 0.37 and 0.35 and r = 0.41 and 0.42, respectively). In addition, MPV was associated with HPC counts in the CB unit. The p value was less than 0.001 for all associations. PLT count was inversely associated with markers of hematopoietic potential. Median removal of PLTs during processing was 62 percent (range, 40%-84%). All 24 CB units of the subset exhibited CFU-MK growth. In multivariate linear regression analysis, MPV improved prediction of the HPC content of the CB unit compared to prediction with CB volume and nucleated cell concentration only.

CONCLUSION

Mean PLT volume correlated with current markers of CB hematopoietic potential and is potentially useful for evaluating CB collections for banking. The question of the clinical significance of PLT characteristics in CB transplantation remains unanswered.

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.

[Donors selection and retrieval of units in an umbilical cord blood bank]

BACKGROUND AND OBJECTIVE

Umbilical cord blood (UCB) contains hematopoietic stem cells that can be used as an alternative to bone marrow transplantation in certain cases. This study was designed to investigate the influence of obstetric, neonatal and collection factors on the hematopoietic content of UCB donations.

MATERIAL AND METHOD

A total of 391 consecutive maternal-neonatal pairs were evaluated during the prepartum period in the maternity ward at La Fe University Hospital. Maternal, neonatal and collection factors influencing cord blood quality measured as volume, total nucleated cells count, CD34+ cells and colony forming units were analyzed in 2,000 UCB collections.

RESULTS

32.5% of UCB potential donors were excluded, mainly due to obstetrical reasons. Among the collected units, 56% were discarded before cryopreservation, mainly due to low cell counts. In the multivariate analysis, placental weight was a predictor variable for total nucleated cells, CD34+ cells and colony forming units, while the mode of collection influenced the total nucleated cells and CD34+ cell counts.

CONCLUSIONS

The collection of UCB units before placental delivery (using the birth weight as an estimation of the placental weight) could be added to standard cord blood donors criteria in order to improve the bank efficiency.

Assessment of cord blood hematopoietic cell parameters before and after cryopreservation

BACKGROUND

The testing of cord blood (CB) progenitor and stem cell units for transplantation suitability involves enumeration of total nucleated cells before freezing. CD34+ cell counts may also be a means of determining suitability. Studies have been conducted to evaluate how specific storage conditions influence cell counts.

STUDY DESIGN AND METHODS

CB units were processed by hydroxyethyl starch volume reduction. Cryopreserved-thawed samples were diluted 1:3 without washing. CD34+ cells were measured with three commercially available assay methods. In specific studies, apoptosis-indicating reagents were included. CB units were analyzed for nucleated cells, aldehyde dehydrogenase-containing cells, and progenitor colonies.

RESULTS

CD34+ cell levels and nucleated cells were retained during storage in test tubes at 1 to 6 degrees C for 3 days. Cryopreserved-thawed samples showed a reduction in CD34+ cells relative to prefreeze levels with the largest decrease with the Stem-Kit (Beckman Coulter) restricted gating procedure. Prefreeze samples contained minimal numbers of presumed apoptotic cells detected with 7-aminoactinomycin D or SYTO16, but after cryopreservation-thawing there was an increase. Nucleated cell levels determined with a hematology analyzer or flow cytometry were reduced after thawing. Cryopreservation-thawing reduced the percentage of CD34+ cells positive for the presence of aldehyde dehydrogenase and the number of progenitor colonies. These differences were significant.

CONCLUSION

These studies indicate that CD34+ cell counts were maintained when CB samples were stored at 1 to 6 degrees C in test tubes for 3 days. Cryopreservation-thawing resulted in changes in a number of parameters including the percentage of CD34+ cells that were aldehyde dehydrogenase(+) and the number of 7-aminoactinomycin D(+) cells and SYTO16(low) cells.

Umbilical cord blood-derived progenitor cells enhance muscle regeneration in mouse hindlimb ischemia model

Progenitor cell therapy is a potential new treatment option for ischemic conditions in the myocardium and skeletal muscles. However, it remains unclear whether umbilical cord blood (UCB)-derived progenitor cells can provide therapeutic effects in ischemic muscles and whether ex vivo gene transfer can be used for improving the effect. In this study, the use of a lentiviral vector led to efficient transduction of both UCB-derived hematopoietic stem cells (HSCs) and mesenchymal stem cells (MSCs). Our method resulted in a long-term transgene expression and did not alter the differentiation potential of either HSCs or MSCs. In addition, we studied the therapeutic potential of CD133(+) and MSC progenitor cells transduced ex vivo with lentiviruses encoding the mature form of vascular endothelial growth factor D (VEGF-D(DeltaNDeltaC)) or the enhanced green fluorescent protein (eGFP) marker gene in a nude mouse model of skeletal muscle ischemia. Progenitor cells enhanced the regeneration of ischemic muscles without a detectable long-term engraftment of either CD133(+) or MSC progenitor cells. Our results show that, rather than directly participating in angiogenesis or skeletal myogenesis, UCB-derived progenitor cells indirectly enhance the regenerative capacity of skeletal muscle after acute ischemic injury. However, VEGF-D gene transfer of progenitor cells did not improve the therapeutic effect in ischemic muscles.

Optimizing donor selection in order to establish a cord blood banking facility: maternal and obstetric factors impact

In this study, we analyzed the obstetric factors affecting total nucleated cells (TNC) content of cord blood units to establish the criteria for umbilical cord blood (UCB) donor selection in our geographic area.

UCB was collected from normal uncomplicated pregnancies. In every case, following data were recorded: (1) gestation length; (2) type of delivery (cesarean or vaginal); and (3) newborn characteristics: weight and sex. For each sample, TNC content, percentage and number of CD34+ cells, and viability were analyzed.

The results showed that TNC content increases with cord blood volume, gestational length and newborn weight. The mean blood volume and the mean TNC per unit were 42.37 ± 13.5 ml and 55.49 ± 19.4 × 107, respectively. Stepwise regression analysis revealed a positive and significant correlation (r= 0.89) between these two variables. Meanwhile the CD34+ cell content remains unchanged in deliveries at 32–40 weeks of gestation. The mean CD34+ percentage obtained was 0.37 ± 0.06, and the total number of CD34+ cells was 4.827 ± 0.8204 × 104 / mL UCB.

Concluding, the maternal and obstetric factors have a significant impact on UCB cell quantity and quality. The main criteria for UCB collection and storage resulted to be: a gestational age higher than 36–40 weeks and newborn weight > 3200g; gestation number ≤ 2 and placental weight > 700g can be added to the standard criteria to improve the bank efficiency. Our results have also become helpful in evaluating stored UCB units to establish the adequacy for clinical transplant utilization.

Cord blood volume reduction using an automated system (Sepax) vs. a semi-automated system (Optipress II) and a manual method (hydroxyethyl starch sedimentation) for routine cord blood banking: a comparative study

Background With the development of cord blood banking, solutions have to be found to solve the storage space problem, by reducing the volume of cord blood units (CBU). Methods We compared total nucleated cell (TNC) and CD34(+) cell counts before and after processing with three different CBU volume reduction methods used consecutively in our bank: a manual method based on hydroxyethyl starch sedimentation (HES) (n=447), a top-and-bottom (TB) semi-automated method (n=181) using Optipress II, and the Sepax automated method (n=213). Statistical analysis was done using t-tests, linear regression and Spearman correlation coefficients. Adjusted variables included TNC, CD34(+) cell counts, CD34(+) cell percentage and CB volume before processing. Results TNC recovery was higher with Sepax (80.3+/-7.7%) than with HES (76.8+/-9.1%) and TB (60.7+/-13.5%) (P<0.0001, both). It was higher with HES than with TB (P<0.0001). CD34(+) cell recovery was higher with Sepax (86+/-11.6%) than with HES (81.5+/-12.5%) and TB (82.0+/-17.7%) (P<0.008 and <0.0001, respectively) and results with HES and TB were not significantly different (P=0.7). Interestingly, with Sepax, TNC and CD34(+) cell recoveries were not correlated with pre-processing values (P=0.8 and 0.4, respectively). Discussion In conclusion, the Sepax volume reduction method allows higher TNC and CD34(+) cell recoveries.

Human umbilical cord blood cells do not improve sensorimotor or cognitive outcome following transient middle cerebral artery occlusion in rats

The present study investigated effects of human umbilical cord blood (HUCB) cells on sensorimotor, cognitive, and histological outcome in rats subjected to transient middle cerebral artery occlusion (MCAO). Halothane anesthetized adult male Wistar rats were subjected to transient MCAO for 2 h. HUCB cells (mononuclear 1-5x10(7) or Lin(-) cells 1-5x10(5)) were administered intravenously after 24 h recovery. The limb-placing test was performed on postoperative days 2, 4, 6, 9, 12, 16, and 20. In addition, beam-walking and cylinder tests were used to assess sensorimotor function at baseline, and on postoperative days 4, 12, and 20. Morris water-maze was used to assess cognitive performance on postoperative days 22-24. Subsequently, rats were perfused for measurement of infarct volumes and detection of HUCB cells by immunohistochemistry (MAB1281). MCAO rats showed a partial spontaneous recovery in sensorimotor function during the follow-up. However, the recovery profile was similar in MCAO controls and in MCAO rats that received HUCB cells. HUCB did not affect impaired water-maze performance of MCAO rats. Only few human nuclei-specific MAB1281-positive cells were detected in the ipsilateral hemisphere in MCAO rats that received HUCB cells. Infarct volumes did not differ between the experimental groups. A group of additional rats were used to further study biodistribution of intravenously given (111)In-oxine-labelled mononuclear HUCB cells in MCAO and sham-operated rats. SPECT imaging data indicated a high tracer uptake in the lung, liver, spleen, and kidney, but not in the brain immediately after administration or 24 h post-administration. The present study suggests that HUCB cells do not improve functional recovery or histological outcome in MCAO rats after systemic administration because of limited migration of cells in the ischemic brain.

Factors associated with parameters of engraftment potential of umbilical cord blood

BACKGROUND

Umbilical cord blood (UCB) is an acceptable source of hematopoietic cells for transplantation with success being associated with the nucleated cell count (NCC), CD34+ cells, and colony-forming unit-granulocyte-macrophage (CFU-GM) content infused. A total of 1033 UCB samples with neonatal and paternal characteristics that might influence hematopoietic content were examined.

STUDY DESIGN AND METHODS

UCB samples were screened, processed, and reevaluated for the above cell counts. These parameters of engraftment potential were analyzed for associations with neonatal and parental characteristics.

RESULTS

Postprocessed NCCs (median, 6.53 x 10(8)+/- 2.80 x 10(8) SD; mean 7.30 x 10(8)), CD34+ counts (median, 2.02 x 10(6) +/- 2.20 x 10(6) SD; mean, 2.65 x 10(6); r = 0.66; p < 0.001), and CFU-GM content (median, 2.65 x 10(5) +/- 3.16 x 10(5) SD; mean, 3.54 x 10(5); r = 0.61; p < 0.001) all were strongly interrelated. Both initial volume (median, 77.5 +/- 26.2 mL SD; mean, 81.9 mL) and initial NCC (median, 9.75 x 10(8) +/- 4.88 x 10(8) SD; mean, 10.9 x 10(8)) correlated well with postprocessed NCC (r = 0.60; r = 0.90; p < 0.01), CD34+ count (r = 0.40; r = 0.63; p < 0.01), and CFU-GM content (r = 0.38; r = 0.59; p < 0.01), with a stronger relationship seen with initial NCC. Infant birth weight (specifically, >3000 g), but not sex, gestational age, or cytomegalovirus status correlated strongly with collection volume and UCB cell counts. Units from minority volunteers contained relatively smaller volumes and hematopoietic content.

CONCLUSION

UCB banks should emphasize selecting the heaviest infants and processing large-volume units with high NCCs to optimize hematopoietic potential. Minority recruitment should be encouraged with consideration given to inherent racial differences in cell counts. There does not appear to be a significant relationship between other neonatal and parental characteristics and that of engraftment potential.

Early apoptosis in CD34+ cells as a potential heterogeneity in quality of cryopreserved umbilical cord blood

The increased use of umbilical cord blood (UCB) raises issues regarding the quality of cryopreserved UCB. This study investigated whether early apoptosis of CD34+ cells is part of the functional heterogeneity of cryopreserved UCB. Annexin V binding of CD34+ PI(-) cells showed wide variations in both fresh and cryopreserved UCBs, with greater variation among units frozen for > 5 years. Xenotransplantation of sorted cells into non-obese diabetic severe combined immunodeficient mice demonstrated that the Annexin V assay identified most repopulating activities in UCB units. Thus, early apoptosis of CD34+ cells could influence the outcome of transplantation using cryopreserved UCB.

Optimization of immunomagnetic separation for cord blood-derived hematopoietic stem cells

BACKGROUND

There is a growing interest in cord blood as a source of primitive stem cells with the capacity for multilineage differentiation. Pure cell fractions are needed for the characterization and in vitro expansion of stem cells as well as for their use in preclinical research. However, enrichment of stem cells is challenging due to the lack of stem cell-specific markers and gentle protocols for the isolation of highly pure stem cell fractions. Protocols developed for the enrichment of peripheral blood-derived stem cells have been found to be suboptimal for cord blood.

RESULTS

In this study, immunomagnetic cell sorting protocols to purify CD34+, CD133+ and Lin- cells from fresh and cryopreserved cord blood were optimized. Reproducible purities of up to 97% were reached. The selected cells were highly viable having substantial colony-forming potential.

CONCLUSION

The optimized protocols enable rapid enrichment of highly pure hematopoietic stem cells from both fresh and cryopreserved cord blood.

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.

Multiple-laboratory comparison of in vitro assays utilized to characterize hematopoietic cells in cord blood

BACKGROUND

Understanding the variability in results obtained by multiple laboratories is important because cord blood units are distributed worldwide for transplantation.

STUDY DESIGN AND METHODS

Four exercises were conducted by multiple laboratories to assess assay variability on nucleated cell (NC), mononuclear cell (MNC) by hematology analyzers [HAs], and CD34+ cell (flow cytometry) measurements. Exercise 1 was an intralaboratory exercise in which the reproducibility of cell measurements was determined. Exercises 2 and 3 involved the shipment of identical processed cord blood samples. In Exercise 2, laboratory-specific methods were utilized. In Exercise 3, two commercial CD34+ cell methods (Stem-Kit and TruCOUNT) were used. In Exercise 4, CD34+ cell levels were determined on repetitive regating of identical list-mode files.

RESULTS

Intralaboratory reproducibility was highest for NC measurements and lowest for CD34+ cell measurements. In Exercise 2, all laboratories except one utilized HA with an impedance technology and determined comparable results for NC and MNC levels, whereas the other laboratory utilized a HA with an optical counting method. Substantial variation was observed on measuring CD34+ cells with ranges of 32 to 141, 32 to 66, and 25 to 116 CD34+ cells per microL for the three identical samples. In Exercise 3, on the use of one specific commercial assay, the ranges of CD34+ levels were 214 to 411 and 62 to 178 cells per microL for the two identical samples. Nearly all participating laboratories determined comparable CD34+ levels on the use of identical list-mode files.

CONCLUSION

These studies indicate that substantial variability in CD34+ cell levels were determined with flow cytometry. The variability in NC and MNC levels was minimal with HA methodology.

The effect of cryopreservation on clonogenic capacity and in vitro expansion potential of umbilical cord blood progenitor cells

BACKGROUND

Umbilical cord blood progenitor cells have been demonstrated to possess significant advantages over bone marrow in terms of proliferative capacity and immunologic reactivity. But the low number of hematopoeitic stem cells (HSC) is the most important limitation of its use. The ex vivo expansion of cord blood progenitor cells is the current strategy to overcome this problem. Furthermore, among the factors that enable successful cord blood transplantation is the ability to store and subsequently recover a sufficient number of viable cells. Since it would be costly to expand umbilical cord blood (UCB) progenitor cells, it is important to determine the feasibility and reproducibility of progenitor cell expansion after cryopreservation. We evaluated whether cryopreservation procedures might impair the clonogenic capacity and in vitro expansion of UCB.

MATERIALS AND METHODS

We evaluated the cell viability, clonogenic capacity, CD34+38- content and in vitro expansion potential of progenitor cells from UCB (n = 10) separated mononuclear cells (MNC), before and after 1 month of cryopreservation by programmed rate freezing.

RESULTS

Although cell viability decreased after cryopreservation (P < .05), there was no significant difference in CD34+ or CD34+38- absolute count, colonogenic capacity and in vitro expansion potential of cord blood progenitor cells (P > .05).

CONCLUSIONS

Since the survival of CD34+ cells was greater than other elements, CD34+ cells seem more tolerant to cryopreservation than the other nucleated populations. Moreover in vitro expansion of UCB progenitor cells may be obtained following cryopreservation. Our results suggest that cryopreservation procedures do not impair the clonogenic capacity and in vitro expansion potential of cord blood stem/progenitor cells.

Multi-laboratory evaluation of procedures for reducing the volume of cord blood: influence on cell recoveries

BACKGROUND

Various procedures can be used to isolate stem and progenitor cells from cord blood. This study evaluated the hydroxyethyl starch sedimentation (HES) with two centrifugation steps, and the top and bottom (T&B) isolation of buffy coat following a single centrifugation, and two filter systems for processing cord blood, one developed by Asahi Kasei Medical (filter A) and the second by Terumo (filter B).

METHODS

Each of seven laboratories was randomly assigned the evaluation of either the HES or T&B method and one of the filter methods (n=8 cord blood units, per laboratory, for each method). The leukocyte-containing fraction with the stem/progenitor cells was recovered from the filters by reverse flushing. Utilizing the routine traditional processing and testing procedures of each laboratory, in vitro parameters were determined, with samples obtained after collection, after processing and after freezing/thawing. The results were expressed as the percentage recovery of viable cells in processed vs. collected samples (performance 1; PF1) and in thawed vs. processed samples (performance 2; PF2). The composite results obtained by the seven laboratories were summarized.

RESULTS

The median PF1 percentage recovery of total nucleated cells (TNC) was comparable with both traditional methods (HES 79%, T&B 86%) and statistically reduced with both filtration procedures (filter A 58%, filter B 61%). Mononuclear cell (MNC) PF1 recovery was highest statistically with the T&B method (91%) and reduced on using filter A (77%) and filter B (70%) and the HES method (72%). CD34+ cell recovery was judged to be essentially comparable with the four methods, although the range of unit recoveries differed. The percentage recovery of TNC and MNC in PF1 was influenced by the volume of the collected cord blood, especially with use of the filtration procedures. This correlated with TNC content. A greater percentage of red cells and platelets was removed during processing with both filter methods. The time to process cord blood preparations with filter A was significantly shorter than the other methods. Processing with the HES method took the longest time. The recoveries for TNC, MNC and CD34+ cells in PF2 did not appear to be influenced by the specific processing procedure.

DISCUSSION

These data indicate that filters that capture stem and progenitor cells may be an appropriate methodology for processing cord blood collected for banking.

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.

Cord blood hematopoietic progenitor cell concentration and infant sex

BACKGROUND

Characterization of cord blood facilitates understanding of the factors affecting cord blood transplant quality and improvement of transplantation results. Cord blood obtained from male and female infants has not been thoroughly characterized.

STUDY DESIGN AND METHODS

A study was performed to test the hypothesis that the cord blood hematopoietic progenitor cell content-of which the CD34+ cell and colony-forming unit (CFU) concentrations were taken as markers-would not only associate with birth weight but also with sex. The hematopoietic progenitor cell concentrations of 1999 healthy infants (47% female) were analyzed in a cord blood bank setting.

RESULTS

Male infants had significantly higher median CD34+ cell concentrations than female infants (31.8/microL vs. 30.2/microL, respectively; p = 0.03). Although the disparity in absolute concentrations was small, it was 5.3 percent. In CFU subgroup analysis, the median CFU-mixed concentration of male infants (11.1/microL) was higher than in female infants (9.9/microL; p = 0.03). The difference was more pronounced when cumulative frequencies of the CFU-mixed concentrations from cesarean section deliveries were compared. In multivariate linear regression analysis, the positive influence of male sex on the CD34+ cell concentration was significant (p < 0.05). The expected higher median nucleated cell concentration of female compared to male infants (13.9 x 10(9)/L vs. 13.3 x 10(9)/L, respectively; p = 0.0001) was mainly due to the higher neutrophil concentration of female infants (7.1 x 10(9)/L vs. 6.5 x 10(9)/L, respectively, p < 0.0001).

CONCLUSION

Cord blood hematopoietic progenitor cell concentration was higher in male infants, even after correcting for birth weight. Sex may affect the hematopoietic potential of cord blood transplants.

Impact of donor- and collection-related variables on product quality in ex utero cord blood banking

BACKGROUND

Optimizing product quality is a current focus in cord blood banking. This study evaluates the role of selected donor- and collection-related variables.

STUDY DESIGN AND METHODS

Retrospective review was performed of cord blood units (CBUs) collected ex utero between February 1, 2000, and February 28, 2002. Preprocessing volume and total nucleated cell (TNC) counts and postprocessing CD34 cell counts were used as product quality indicators.

RESULTS

Of 2084 CBUs, volume determinations and TNC counts were performed on 1628 and CD34+ counts on 1124 CBUs. Mean volume and TNC and CD34+ counts were 85.2 mL, 118.9 x 10(7), and 5.2 x 10(6), respectively. In univariate analysis, placental weight of greater than 500 g and meconium in amniotic fluid correlated with better volume and TNC and CD34+ counts. Greater than 40 weeks' gestation predicted enhanced volume and TNC count. Cesarean section, two- versus one-person collection, and not greater than 5 minutes between placental delivery and collection produced superior volume. Increased TNC count was also seen in Caucasian women, primigravidae, female newborns, and collection duration of more than 5 minutes. A time between delivery of newborn and placenta of not greater than 10 minutes predicted better volume and CD34+ count. By regression analysis, collection within not greater than 5 minutes of placental delivery produced superior volume and TNC count.

CONCLUSION

Donor selection and collection technique modifications may improve product quality. TNC count appears to be more affected by different variables than CD34+ count.

Utility of bag segment and cryovial samples for quality control and confirmatory HLA typing in umbilical cord blood banking

Many cord blood (CB) banks have been established worldwide as a response to the increasing number of CB transplantations. In this study, we describe a quality control program in which the utility of an integral bag segment and cryovial containing aliquots of cryopreserved product as haematopoietic content control and HLA typing confirmation for CB units has been evaluated. For this purpose, every month one stored CB unit and its satellite cryovials were thawed and washed. Nucleated cell counts, viability and clonogenic assays were performed from the bag and cryovial before washing. After washing, total nucleated cell, CD34+ counts, viability, and clonogenic assays were performed from the bag. In order to assure the ability of bag segments to confirm hematopoietic potential of CB units, clonogenic assays and viability were performed from attached segments of 10 CB units and the results were compared with those from bags and cryovials. When comparing all variables between thawed bag and cryovial samples, they showed similar results. Mean colony-forming unit (CFU) content of segment samples was 118.8 +/- 93.72 x 10(4) that resulted similar to bags and cryovials haematopoietic content. In conclusion, the quality control system described in this paper demonstrates that CB units are processed preserving the quantity and quality of the progenitor cells. The contiguous segment haematopoietic content is representative of the final product.

High birth weight is associated with human leukocyte antigen (HLA) DRB1*13 in full-term infants

In cord blood banking, substantial amounts of data on infants and cord blood are gathered at high cost, including birth weights and human leukocyte antigen (HLA) genotypes. As certain HLA alleles have been associated with protective host responses, it is possible that an HLA allele, or another factor linked to it, might even affect normal intrauterine growth. We explored cord blood bank data (n = 1381 infants) to elucidate whether there is an association between birth weight and HLA class II (DRB1) alleles. HLA DRB1 data were available from 1263 infants. We observed an association between birth weight and HLA DRB1*13, which was over-represented among full-term infants with the highest birth weights. The association remained when the birth weight was corrected for varying gestational age (relative birth weight) according to gender (P = 0.015). After correction of the P-value for multiple comparisons, the association was not statistically significant. However, when the birth weights of all infants were analysed for the effect of DRB1*13, infants positive for HLA DRB1*13 (n = 319) were found to have higher birth weights than infants negative for this allele (n = 944; median 3690 g vs. 3650 g, respectively; P = 0.044). Although the difference in median birth weight was only 40 g, it may be considered significant because it appeared after segregation of the infants into two groups according to the single HLA class II allele group earlier associated with protection against, for example, childhood type 1 diabetes and certain infectious diseases. The present finding may thus suggest identification of a new factor affecting normal intrauterine growth.

Optimizing donor selection in a cord blood bank

OBJECTIVES

The main limitation factor for the wide use of umbilical cord blood (UCB) as a source of hematopoietic progenitor for transplantation is cell dose. One of the specific areas identified by some studies for improvement of UCB collection is donor selection.

METHODS

Over a 3-mth period, 391 consecutive maternal-neonatal pairs were evaluated during the pre-partum period in the maternity ward at La Fe University Hospital (Valencia) by the Cord Blood Bank staff. Reasons for discarding umbilical cord blood donors and collected UCB units at the Cord Blood Bank in Valencia have been analysed. Obstetric factors influencing TNC content of 1300 collected UCB units have been determined, in order to establish obstetric criteria for cord blood donors selection in our geographic area.

RESULTS

Only 32.5% of potential cord blood donors were refused. Among 1300 UCB collected, 506 (38.9%) were discarded before cryopreservation, mainly due to low cell counts. Multivariate analyses showed that the main significant factors influencing nucleated cell count were the weight of the placenta, sex of newborn and mode of collection.

CONCLUSIONS

Our study shows that maternal medical histories must be completely reviewed by medical staff before collection of the UCB. Obstetrical factors influence cell content of UCB and could be added to standard cord blood donor criteria in order to improve the bank efficiency.