Mesenchymal Stromal Cells from Perinatal Tissues as an Alternative for Ex Vivo Expansion of Hematopoietic Progenitor and Stem Cells from Umbilical Cord Blood.

Umbilical cord blood (UCB) serves as a source of hematopoietic stem and progenitor cells (HSPCs) utilized in the regeneration of hematopoietic and immune systems, forming a crucial part of the treatment for various benign and malignant hematological diseases. UCB has been utilized as an alternative HSPC source to bone marrow (BM). Although the use of UCB has extended transplantation access to many individuals, it still encounters significant challenges in selecting a histocompatible UCB unit with an adequate cell dose for a substantial proportion of adults with malignant hematological diseases. Consequently, recent research has focused on developing ex vivo expansion strategies for UCB HSPCs. Our results demonstrate that co-cultures with the investigated mesenchymal stromal cells (MSCs) enable a 10- to 15-fold increase in the cellular dose of UCB HSPCs while partially regulating the proliferation capacity when compared to HSPCs expanded with early acting cytokines. Furthermore, the secretory profile of UCB-derived MSCs closely resembles that of BM-derived MSCs. Moreover, both co-cultures exhibit alterations in cytokine secretion, which could potentially impact HSPC proliferation during the expansion process. This study underscores the fact that UCB-derived MSCs possess a remarkably similar supportive capacity to BM-derived MSCs, implying their potential use as feeder layers in the ex vivo expansion process of HSPCs.

Clinical Outcomes of Unrelated Umbilical Cord Blood Graft vs. Haploidentical Donor Transplantation: Critical Issues for an Adequate Comparison.

Unrelated umbilical cord blood (UCB) and haploidentical grafts have been used for allogeneic hematopoietic stem and progenitor cell (HSPC) transplantation in patients without a related or non-related human leukocyte antigen (HLA)-matched donor. The less stringent HLA-matching requirement in both sources raises an important possibility for patients in need of urgent transplantation to treat any hematological disease. Selection of the best alternative donor is a difficult task that will depend on donor criteria, center experience, patient disease conditions, and risk, among others. Most comparisons available in scientific publications between both graft sources are obtained from retrospective analysis in wide time windows and a heterogeneous number of patients, types of disease, disease stages, previous treatments, graft source, conditioning regimen, graft vs. host disease (GVHD) approach, and evaluable endpoints. There is also an evident impact of the economic traits since low-income countries must consider less expensive treatments to satisfy the needs of the patients in the most effective possible path. Therefore, haploidentical transplantation could be an appealing option, even though it has not been completely established if any chronic treatment derived from the procedure could become a higher cost. In Colombia, there is a huge experience in UCB transplantation especially in units of pediatric transplantation where benign indications are more common than in adults. Due to the availability of a public UCB bank and HLA high-resolution typing in Colombia, there is a wider inventory of cord blood donors. Unfortunately, we do not have an unrelated bone marrow donor registry, so UCB is an important source along with haploidentical transplantation to consider in decision-making. This minireview focuses on comparing the main issues associated with the use of both HSCP sources and provides tools for physicians who face the difficult decision between these alternative donor sources.

Human Leukocyte Antigen and Red Blood Cells Impact Umbilical Cord Blood CD34+ Cell Viability after Thawing.

Hematopoietic progenitor cell (HPC) transplantation is a treatment option for malignant and nonmalignant diseases. Umbilical cord blood (UCB) is an important HPC source, mainly for pediatric patients. It has been demonstrated that human leukocyte antigen (HLA) matching and cell dose are the most important features impacting clinical outcomes. However, UCB matching is performed using low resolution HLA typing and it has been demonstrated that the unnoticed mismatches negatively impact the transplant. Since we found differences in CD34+ viability after thawing of UCB units matched for two different patients (p = 0.05), we presumed a possible association between CD34+ cell viability and HLA. We performed a multivariate linear model (n = 67), comprising pre-cryopreservation variables and high resolution HLA genotypes separately. We found that pre-cryopreservation red blood cells (RBC), granulocytes, and viable CD34+ cell count significantly impacted CD34+ viability after thawing, along with HLA-B or -C (R2 = 0.95, p = 0.01; R2 = 0.56, p = 0.007, respectively). Although HLA-B*40:02 may have a negative impact on CD34+ cell viability, RBC depletion significantly improves it.

HLA-A, -B, -C, -DRB1 and -DQB1 allele and haplotype frequencies of 1463 umbilical cord blood units typed in high resolution from Bogotá, Colombia.

Allele and haplotype frequencies were calculated from 1463 umbilical cord blood (UCB) units, from Bogotá (Colombia) donors, HLA-typed in high resolution. This is the first report using allele-level typed colombian samples of five HLA loci related to hematopoietic stem cell transplantation (HLA-A, -B, -C, -DRB1 and -DQB1). The most frequent haplotype found in our sample was A*24:02g ∼ B*35:43g ∼ C*01:02g ∼ DRB1*04:07g ∼ DQB1*03:02g (4.14%). Our data are available at the Allele Frequencies Net Database under the code AFND3604.

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.

Modulating p56Lck in T-Cells by a Chimeric Peptide Comprising Two Functionally Different Motifs of Tip from Herpesvirus saimiri.

The Lck interacting protein Tip of Herpesvirus saimiri is responsible for T-cell transformation both in vitro and in vivo. Here we designed the chimeric peptide hTip-CSKH, comprising the Lck specific interacting motif CSKH of Tip and its hydrophobic transmembrane sequence (hTip), the latter as a vector targeting lipid rafts. We found that hTip-CSKH can induce a fivefold increase in proliferation of human and Aotus sp. T-cells. Costimulation with PMA did not enhance this proliferation rate, suggesting that hTip-CSKH is sufficient and independent of further PKC stimulation. We also found that human Lck phosphorylation was increased earlier after stimulation when T-cells were incubated previously with hTip-CSKH, supporting a strong signalling and proliferative effect of the chimeric peptide. Additionally, Lck downstream signalling was evident with hTip-CSKH but not with control peptides. Importantly, hTip-CSKH could be identified in heavy lipid rafts membrane fractions, a compartment where important T-cell signalling molecules (LAT, Ras, and Lck) are present during T-cell activation. Interestingly, hTip-CSKH was inhibitory to Jurkat cells, in total agreement with the different signalling pathways and activation requirements of this leukemic cell line. These results provide the basis for the development of new compounds capable of modulating therapeutic targets present in lipid rafts.

Optimised cord blood sample selection for small­scale CD34+ cell immunomagnetic isolation.

Haematopoietic stem cells (HSCs) are defined as multipotential cells, capable of self-renewal and reconstituting in vivo the haematopoietic compartment. The CD34 antigen is considered an important HSCs marker in humans. Immunomagnetic isolation, by targeting CD34 antigen, is widely used for human HSC separation. This method allows the enrichment of human HSCs that are present at low frequencies in umbilical cord blood (CB). Immunomagnetic CD34+-cell isolation reproducibility, regarding cell yield and purity, is affected by the CD34+ cell frequency and total cell numbers present in a given sample; CB HSC purification may thus yield variable results, which also depend on the volume and density fractionation-derived cell loss of a CB sample. The uncertainty of such an outcome and associated technical costs call for a cost-effective sample screening strategy. A correlation analysis using clinical and laboratory data from 59 CB samples was performed to establish predictive variables for CD34+-immunomagnetic HSCs isolation. This study described the positive association of CD34+-cell isolation with white and red cell numbers present after cell fractionation. Furthermore, purity has been correlated with lymphocyte percentages. Predictive variable cut-off values, which are particularly useful in situations involving low CB volumes being collected (such as prevalent late umbilical cord clamping clinical practice), were proposed for HSC isolation sampling. Using the simple and cost-effective CB sample screening criteria described here would lead to avoiding costly inefficient sample purification, thereby ensuring that pure CD34+ cells are obtained in the desired numbers following CD34 immunomagnetic isolation.

Co-culture of hematopoietic stem cells with mesenchymal stem cells increases VCAM-1-dependent migration of primitive hematopoietic stem cells.

Hematopoietic stem cells (HSC) lose their capacity for engraftment during ex vivo cytokine expansion. It has been shown that mesenchymal stem cells (MSC) improve HSC transplantability; however, the molecular mechanisms responsible for this effect have not yet been completely elucidated. This paper reports that expanding HSC in co-culture with MSC enhances a vascular cell adhesion molecule (VCAM-1)-dependent pro-migratory phenotype. MSC did not regulate the HSC expression of CD49d (VCAM-1 counter-receptor molecule), but did decrease the cytokine-induced HSC VCAM-1-mediated pro-adhesive phenotype. Co-culture with MSC reduced the expression of the inactive conformation of lymphocyte function-associated antigen (LFA-1) at the HSC uropod, and induced higher expression of an LFA-1 activation epitope. Interestingly, VCAM-1-dependent HSC migration was modulated by targeting this LFA-1 high affinity form, suggesting integrin cross-regulation. VCAM-1-mediated HSC transmigration appeared to favor the more primitive HSC immunophenotype. Our results suggested that co-culture with MSC improved VCAM-1-dependent migration of primitive HSC, which was affected in ex vivo cytokine-expanded HSCs by a mechanism involving LFA-1 modulation.