Cord blood hematopoietic progenitor cell concentration and infant sex

[Harvest of Stem Cells from Umbilical Cord Blood: Relevance of Perinatal Factors for the Quality of Umbilical Cord Transplant Units]

Einleitung Nabelschnurblut (NSB) enthält hämatopoetische Stammzellen mit therapeutischem Potenzial und einzigartigen zellulären Eigenschaften. Aufgrund der begrenzten Anzahl an Stammzellen im NSB (Surrogatmarker total nucleated cells, TNC) eignet sich nur jede fünfte Spende für eine Transplantation. Ziel dieser Studie war es, zu untersuchen, ob prädiktive Faktoren für eine TNC-Zahl über der 99. Perzentile existieren.

Material und Methodik Retrospektive Datenanalyse der 100 größten NSB-Spenden (Top100-Kohorte) aus 2299 registrierten Einheiten. Unterschiede zwischen maternalen, fetalen und geburtshilflichen Faktoren wurden analysiert und mit einer standardisierten Kohorte von 731 NSB-Spenden verglichen.

Ergebnisse Das mütterliche Alter und der BMI in der Top100-Kohorte waren höher als in der Vergleichskohorte (32 vs. 31 Jahre, p=0,007; 30 kg/m2 vs. 29 kg/m2, p=0,024). Es gab mehr Erstgebärende (76,0 vs. 62,8%, p=0,013) und Gestationsdiabetikerinnen (5,00 vs. 1,65%, p=0,044). Die Schwangerschaftswoche, das Geburtsgewicht, der Anteil vaginal-operativer Geburten und sekundärer Sectiones war in der Top100-Kohorte höher (40+4 vs. 40+1 SSW, p=0,002), (3700 vs. 3450 g, p<0,001), (53,0 vs. 22,7%, p<0,001) (10 vs. 6,2%, p=0,014).

Fazit Für eine erfolgreiche Transplantation ist die Höhe der TNC-Zahl entscheidend. Vaginal-operative Entbindungen, sekundäre Sectiones und ein Geburtsgewicht über 3700 g sind günstige Faktoren. Gerade bei Geburten mit einem pathologischen Verlauf sollte nach sicherer Versorgung von Mutter und Kind nicht auf eine Entnahme verzichtet werden.

Human Umbilical Cord: Information Mine in Sex-Specific Medicine

Biological differences between sexes should be considered in all stages of research, as sexual dimorphism starts in utero leading to sex-specific fetal programming. In numerous biomedical fields, there is still a lack of stratification by sex despite primary cultured cells retaining memory of the sex and of the donor. The sex of donors in biological research must be known because variations in cells and cellular components can be used as endpoints, biomarkers and/or targets of pharmacological studies. This selective review focuses on the current findings regarding sex differences observed in the umbilical cord, a widely used source of research samples, both in the blood and in the circulating cells, as well as in the different cellular models obtainable from it. Moreover, an overview on sex differences in fetal programming is reported. As it emerges that the sex variable is still often forgotten in experimental models, we suggest that it should be mandatory to adopt sex-oriented research, because only awareness of these issues can lead to innovative research.

Impact of maternal and neonatal factors on umbilical cord CD34+ cells

Background

The achievement of optimal number of CD34⁺ umbilical cord stem cells is essential for successful umbilical cord stem cell transplantation. So the aim of this study was to assess the potential effect of both maternal and neonatal factors on the umbilical cord blood CD34⁺ cell count.

Methods

The study was done on umbilical cord blood samples obtained from 20 mothers during labor. Their ages ranged from 22 to 34 years and were subjected to history taking, physical examination of the baby and assessment of the CD34⁺ cells count in umbilical cord blood.

Results

Number of previous live births and weight of the baby had a significant effect on CD34⁺ cells count while the sex of the baby, delivery route, maternal age and gestation period had no significant effect on CD34⁺ cells count.

Conclusions

Umbilical cord blood-derived CD34⁺ cell count is better with good weight and first babies and decreased with subsequent babies.

Structural and Functional Characterization of Deceased Donor Stem Cells: A Viable Alternative to Living Donor Stem Cells

Stem cells can be isolated from various human tissues including bone marrow (BM) and adipose tissue (AT). Our study outlines a process to isolate adult stem cells from deceased donors. We have shown that cell counts obtained from deceased donor BM were within established living donor parameters. Evaluation of demographic information exhibited a higher percentage of hematopoietic stem cells (HSC) in males versus females, as well as a higher percentage of HSC in the age bracket of 25 years and under. For the first time, we show that deceased donor femur BM grew cell colonies. Our introduction of new technology for nonenzymatic AT processing significantly increased cell recovery over the traditional enzymatic processing method. Cell counts from the deceased donor AT exceeded living donor parameters. Furthermore, our data illustrated that AT from female donors yielded a much higher number of total nucleated cells (TNC) than males. Together, our data demonstrates that our approach to isolate stem cells from deceased donors could be a routine practice to provide a viable alternative to living donor stem cells. This will offer increased accessibility for patients awaiting stem cell therapies.

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.

Influence of neonatal gender on cord blood CD34+ cell amplification and gene expression

The present study attempted to evaluate whether neonatal gender affects the hematopoietic potential of cord blood (CB) transplants and, if so, to determine the underlying molecular mechanisms. CD34⁺ cells from CB were isolated and divided into male and female groups. CD34⁺CD38⁻ cell populations were then compared using fluorescence-assisted cell sorting (FACS) and a colony formation assay was performed. Next, a Genechip microarray analysis was used to identify differentially expressed genes (DEGs). Finally, the Genechip results were validated by FACS analysis. It was revealed that the male group had higher amplification efficiency. Gene ontology analysis indicated differences in the biological function of the DEGs between the two groups. Kyoto Encyclopedia of Genes and Genomes analysis suggested that the hematopoietic cell lineage signaling pathway was upregulated in the male group along with high expression levels of genes including interleukin (IL) 6 signal transducer (glycoprotein 130), IL-7 and IL-7 receptor. It was speculated that this may be partially due to numerous upregulated DEGs being involved in chromosomal segregation and hematopoietic cell lineage signaling pathways in CD34⁺ cells from the male group.

Concentration of the CDCP1 protein in human cord plasma may serve as a predictor of hematopoietic stem and progenitor cell content

Successful hematopoietic stem and progenitor cell (HSPC) transplantation rests upon reliable methods for their enumeration in sources such as cord blood (CB). Methods used today are costly, time consuming and exhaust the limited number of cells needed for transplantation. The aim of this study was to analyze if surplus plasma from CB contains biomarkers that can predict HSPC content in CB. Frozen, surplus plasma from 95 CB units was divided into two groups based on CD34+ cell concentration. Birth weight, gestation age, gender, mode of delivery, collection volume, nucleated cell count and colony forming unit assay results were available. Samples were analyzed with a proximity ligation assay covering 92 different proteins. Two-group t-test with p-values adjusted for false discovery rate (FDR) identified 5 proteins that significantly differed between the two groups. CDCP1 was the most significant (FDR adjusted p-value 0.006). Correlation with CDCP1 concentration was most significant for CD34+ concentration and nucleated cell count. Multivariate analysis showed that CD34 and gender seemed to influence the level of CDCP1. In conclusion, CDCP1 was identified as a potential biomarker of HSPC content in CB. The finding also warrants further investigation for a possible role of CDCP1 in regulating HSPC presence in CB.

From cord to caudate: characterizing umbilical cord blood stem cells and their paracrine interactions with the injured brain

Stem cells are proving to be a promising therapy for a wide range of pediatric disorders, from neonatal hypoxic-ischemic encephalopathy to pediatric leukemia. Owing to their low immunogenicity and ease of availability, umbilical cord blood (UCB) progenitor cells are increasingly replacing fetal- and adult-derived cells in therapeutic settings. Multiple environmental and demographic factors affect the number and type of stem cells extracted from UCB, and these differences have been associated with disparities in outcomes after transplantation. To avoid variations in efficacy, as well as the potential adverse effects of stem cell transplantation, evaluation of the stem cell secretome is critical to identify key paracrine signals released by the stem cells that could be used to provide similar neuroprotective effects to stem cell transplantation. This article describes the cell types found in UCB and reviews the available literature surrounding the effects of collection timing and volume, maternal risk factors, delivery characteristics, and neonatal demographics on the cellular composition of UCB. In addition, the current findings regarding the stem cell secretome are discussed to identify factors that could be used to supplement or replace stem cell transplantation in pediatric neuroprotection.

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.

A new strategy for umbilical cord blood collection developed at the first Colombian public cord blood bank increases total nucleated cell content

BACKGROUND

The total nucleated cell dosage of umbilical cord blood (UCB) is an important factor in determining successful allogeneic hematopoietic stem cell transplantation after a minimum human leukocyte antigen donor-recipient match. The northern South American population is in need of a new-generation cord blood bank that cryopreserves only units with high total nucleated cell content, thereby increasing the likelihood of use. Colombia set up a public cord blood bank in 2014; and, as a result of its research for improving high total nucleated cell content, a new strategy for UCB collection was developed.

STUDY DESIGN AND METHODS

Data from 2933 collected and 759 cryopreserved cord blood units between 2014 and 2015 were analyzed. The correlation of donor and collection variables with cellularity was evaluated. Moreover, blood volume, cell content, CD34+ count, clonogenic capacity, and microbial contamination were assessed comparing the new method, which combines in utero and ex utero techniques, with the conventional strategies.

RESULTS

Multivariate analysis confirmed a correlation between neonatal birth weight and cell content. The new collection method increased total nucleated cell content in approximately 26% and did not alter pre-cryopreservation and post-thaw cell recovery, viability, or clonogenic ability. Furthermore, it showed a remarkably low microbial contamination rate (1.2%).

CONCLUSION

The strategy for UCB collection developed at the first Colombian public cord blood bank increases total nucleated cell content and does not affect unit quality. The existence of this bank is a remarkable breakthrough for Latin-American patients in need of this kind of transplantation.

The effect of maternal and infant factors on cord blood yield

Umbilical cord blood (CB) can be used as an alternative hematopoietic stem cell source for transplantation in hematological malignancy and blood disorders. The success of transplantation is highly related to the levels of total nucleated cell and CD34⁺ cell counts. The evaluation of optimal conditions can decrease the rate of graft rejection due to low cell count and increases the quality of CB units (CBUs) in the blood bank and the success rate of engraftment. To this end, we review the maternal and infant parameters affecting the quality and quantity of CBUs.

Association of CD34+ and CD90+ Stem Cells of Cord Blood with Neonatal Factors: A Cross-sectional Study

OBJECTIVE

To characterize the primitive stem cell content of cord blood with regard to neonatal parameters.

METHODS

In this cross-sectional study, CD34+ and CD90+ cells content were enumerated by flow-cytometry method. Their associations with various neonatal parameters like birth weight, gender, gestational age and mode of delivery were analyzed by univariate analysis. Multivariable linear regression model was then developed to further explain the effect of neonatal factors on these primitive cell counts.

RESULTS

From a total of 106 recruited subjects, gender of the neonate did not have any influence on the expression of these proteins (CD34 and CD90) of cord blood stem cells or progenitors. Multi variable linear regression analysis using CD34+ and CD90+ cell counts as dependent variables revealed that birth weight and the mode of delivery were significant predictors of these cell counts.

CONCLUSIONS

The present study suggests that birth weight and mode of delivery of the neonates influences cord blood stem cell yield.

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.

CD133 allows elaborated discrimination and quantification of haematopoietic progenitor subsets in human haematopoietic stem cell transplants

The success of haematopoietic stem cell (HSC) transplantation largely depends on numbers of transplanted HSCs, which reside in the CD34(+) populations of bone marrow (BM), peripheral blood stem cells (PBSC) and umbilical cord blood (UCB). More specifically HSCs reside in the CD38(low/-) subpopulation, which cannot be objectively discriminated from mature CD34(+)  CD38(+) progenitors. Thus, better marker combinations for the quantification of more primitive haematopoietic stem and progenitor cells in transplants are required. Recently, by combining CD34 and CD133 we could clearly distinguish CD133(+)  CD34(+) multipotent and lympho-myeloid from CD133(low)  CD34(+) erythro-myeloid progenitors in UCB samples. To qualify the assessment of CD133 for routine quality control of adult HSC sources, we analysed the developmental potentials of CD133(+) and CD133(low) subpopulations in BM and PBSC. Similar to UCB, CD133 expression objectively discriminated functionally distinct subpopulations in adult HSC sources. By implementing anti-CD45RA staining, which separates multipotent (CD133(+)  CD34(+)  CD45RA(-) ) from lympho-myeloid (CD133(+)  CD34(+)  CD45RA(+) ) progenitor fractions, UCB was found to contain 2-3 times higher multipotent progenitor frequencies than BM and PBSC. To test for the consistency of CD133 expression, we compared CD133(+)  CD34(+) contents of 128 UCB samples with maternal and obstetrical factors and obtained similar correlations to related studies focusing on CD34(+) cell contents. In conclusion, implementation of anti-CD133 staining into existing routine panels will improve the quality control analyses for HSC transplants.

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.

Index of CD34+ Cells and Mononuclear Cells in the Bone Marrow of Spinal Cord Injury Patients of Different Age Groups: A Comparative Analysis

Introduction. Recent evidence of safety and efficacy of Bone Marrow Mononuclear Cells (BMMNC) in spinal cord injury makes the Bone Marrow (BM) CD34+ percentage and the BMMNC count gain significance. The indices of BM that change with body mass index and aging in general population have been reported but seldom in Spinal Cord Injury (SCI) victims, whose parameters of relevance differ from general population. Herein, we report the indices of BMMNC in SCI victims. Materials and Methods. BMMNCs of 332 SCI patients were isolated under GMP protocols. Cell count by Trypan blue method and CD34+ cells by flow cytometry were documented and analysed across ages and gender. Results. The average BMMNC per ml in the age groups 0–20, 21–40, 41–60, and 61–80 years were 4.71, 4.03, 3.67, and 3.02 million and the CD34+ were 1.05%, 1.04%, 0.94%, and 0.93% respectively. The decline in CD34+ was sharp between 20–40 and 40–60 age groups. Females of reproductive age group had lesser CD34+. Conclusion. The BMMNC and CD34+ percentages decline with aging in SCI victims. Their lower values in females during reproductive age should be analysed for relevance to hormonal influence. This study offers reference values of BMMNC and CD34+ of SCI victims for successful clinical application.

CD133 immunomagnetic separation: effectiveness of the method for CD133(+) isolation from umbilical cord blood

BACKGROUND AIMS

Umbilical cord blood (UCB) is a rich source of stem cells, the characterization and isolation of which requires specific stem cell markers and reliable and reproducible protocols.

METHODS

We assessed CD133 isolation in 39 UCB samples, using a commercial immunomagnetic cell-sorting protocol, and, because of its non-reproducibility, we applied optimized protocols in an effort to improve it. These included extra-labeling of the selected CD133(+) subpopulation and indirect labeling using anti-phycoerythrin (PE) microbeads, goat anti-mouse IgG microbeads or a combination of both. The CD34 isolation was used as a control.

RESULTS

The mononuclear cell fraction expressed 0.53±0.06% CD133. The corresponding value for CD34 was 1.64±0.15%. Following the manufacturer's instructions, the CD34 isolation resulted in a population expressing 93±1.25% CD34 while, after the corresponding process, CD133(+) expression ranged from 10% to 85% (median 60%). The optimized isolation protocols did not result in improved CD133(+) yield. The variation in the purity of the CD133 population cannot be attributed to the different clones of CD133 used, because they do not cross-block, while other factors such as glycosylation, which could possibly interfere, do not apply in normal hematopoietic stem cells (HSC).

CONCLUSIONS

CD34 isolation by the immunomagnetic method results in highly pure CD34(+) population, while the efficient and reproducible yield of a pure CD133(+) population is not feasible. Therefore quantification of the positive cells should follow each isolation procedure in order to confirm the number of CD133(+) cells.

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.

Effects of obstetric factors and storage temperatures on the yield of endothelial colony forming cells from umbilical cord blood

As umbilical cord blood (UCB) is a rich source of endothelial colony-forming cells (ECFC), our aim was twofold: (1) to examine potential obstetric selection criteria for achieving the highest ECFC yields from UCB units, and (2) to determine whether transient storage temperatures of fresh UCB and cryopreservation of UCB units affected ECFC yield and function. ECFC quality was assessed before and after cryopreservation by their clonogenic proliferative potential. Of the 20 factors examined, placental weight was the only statistically significant obstetric factor that predicted ECFC frequency in UCB. Studies on the effects of storage revealed that transient storage of fresh UCB at 4°C reduced ECFC yield compared with storage at 22°C, while cryopreservation of UCB MNCs significantly reduced ECFC recoveries. To our knowledge, this is the first demonstration that placental weight and temperature of storage prior to processing or culture have significant effects on ECFC frequency in UCB. Our studies further support the evidence that cryopreservation of UCB MNCs compromises ECFC recovery.

An integrated microfluidic system for isolation, counting, and sorting of hematopoietic stem cells

This study reports an integrated microfluidic system capable of isolation, counting, and sorting of hematopoietic stem cells (HSCs) from cord blood in an automatic format by utilizing a magnetic-bead-based immunoassay. Three functional modules, including cell isolation, cell counting, and cell sorting modules are integrated on a single chip by using microfluidic technology. The cell isolation module is comprised of a four-membrane-type micromixer for binding of target stem cells and magnetic beads, two pneumatic micropumps for sample transport, and an S-shaped channel for isolation of HSCs using a permanent magnet underneath. The counting and sorting of HSCs are performed by utilizing the cell counting and sorting modules. Experimental results show that a separation efficiency as high as 88% for HSCs from cord blood is achieved within 40 min for a sample volume of 100 mul. Therefore, the development of this integrated microfluidic system may be promising for various applications such as stem cell research and cell therapy.

Impact of maternal and neonatal factors on CD34+ cell count, total nucleated cells, and volume of cord blood

The engraftment outcome of UCB transplantation is highly dependent on cell number. It would be useful to predict CB cell content using information of donor-related variables before cell processing. In this study, CBs were obtained from 1312 single-birth term deliveries in the Buddhist Tzu Chi Stem Cells Center from January 2001 to June 2006. We evaluated whether maternal factors, such as age and race, have an effect on laboratory parameters of hematopoietic content, including CD34+ cell counts, TNCs, and cord blood volume. We also studied the impact of neonatal factors, such as delivery method, gestational age, sex, birth weight, and birth order on the same parameters. In multivariate analysis, babies delivered via Cesarean section had more CD34+ cells and volume, but lower TNCs. Similar results were found for either babies of shorter gestational age or in male infants. Babies with larger birth weight had higher CD34+ cell volume, and TNC, while mothers with fewer previous live births had CB with more TNCs. Maternal age and race had no effect on these laboratory parameters. To conclude, our results suggest that neonatal factors affect CB cell yields. TNCs tend to be more affected by different variables than CD34+ cell counts and volume. These findings may help in collecting CB efficiently and improve the CB transplantation rate.

Isolation of hematopoietic stem cells from human cord blood

Enrichment of hematopoietic stem cells is based on the expression of certain surface antigens, such as CD34 and CD133, or on the lack of expression of lineage-specific antigens. Immunomagnetic positive selection of CD34(+) or CD133(+) cells is performed using paramagnetic microbeads conjugated to specific monoclonal antibodies (anti-human CD34 or anti-human CD133). In negative selection of lineage-negative (Lin(-)) cells, the unwanted cells are labeled with antibodies against known markers for mature hematopoietic cells (CD2, CD3, CD14, CD16, CD19, CD24, CD56, CD66b, and glycophorin A) and retained in the column. Unlabeled cells pass through the column and are collected as the Lin(-) cell fraction. Immunomagnetic cell sorting system MACS is a fast and gentle method to enrich hematopoietic stem cells. Viable and highly pure cells can be separated to be used in various downstream applications, such as flow cytometry and cell culture.

Sex steroids and stem cell function

Gender dimorphisms exist in the pathogenesis of a variety of cardiovascular, cardiopulmonary, neurodegenerative, and endocrine disorders. Estrogens exert immense influence on myocardial remodeling following ischemic insult, partially through paracrine growth hormone production by bone marrow mesenchymal stem cells (MSCs) and endothelial progenitor cells. Estrogens also facilitate the mobilization of endothelial progenitor cells to the ischemic myocardium and enhance neovascularization at the ischemic border zone. Moreover, estrogens limit pathological myocardial remodeling through the inhibitory effects on the proliferation of the cardiac fibroblasts. Androgens also may stimulate endothelial progenitor cell migration from the bone marrow, yet the larger role of androgens in disease pathogenesis is not well characterized. The beneficial effects of sex steroids include alteration of lipid metabolism in preadipocytes, modulation of bone metabolism and skeletal maturation, and prevention of osteoporosis through their effects on osteogenic precursors. In an example of sex steroid-specific effects, neural stem cells exhibit enhanced proliferation in response to estrogens, whereas androgens mediate inhibitory effects on their proliferation. Although stem cells can offer significant therapeutic benefits in various cardiovascular, neurodegenerative, endocrine disorders, and disorders of bone metabolism, a greater understanding of sex hormones on diverse stem cell populations is required to improve their ultimate clinical efficacy. In this review, we focus on the effects of estrogen and testosterone on various stem and progenitor cell types, and their relevant intracellular mechanisms.

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.

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.

Evaluation of Biological Features of Cord Blood Units Collected With Different Methods After Cesarean Section

INTRODUCTION

Cord blood banks are established worldwide as a result of the increased use of umbilical cord blood (UCB) transplantation. The outcomes of this procedure relate to the cell dose of the UCB unit and the UCB collection. The aim of this study was to evaluate whether the mode of collection influenced the biological features of the UCB units.

MATERIALS AND METHODS

We studied 151 UCB units consecutively collected in the cesarean setting with two different methods: in utero after infant delivery and before delivery of the placenta, and ex utero after delivery of placenta.

RESULTS

Sixty-nine UCB units were collected in utero and 82 ex utero. The two groups were comparable for maternal and obstetric factors. The proportion of banked UCB units was similar in the two groups (38% vs 40%, respectively). No statistically significant differences were observed between the methods of collection in term of volume, white blood cell count, total nucleated cell content, CD34(+) cells, and CFU-GM.

CONCLUSION

This preliminary study showed that the two methods of collection in the cesarean setting were overlapping and valid if performed according to standard operating procedures.