Umbilical cord blood transplantation: the first 25 years and beyond. Blood. 2013;122:491-498. [PMID: 23673863 DOI: 10.1182/blood-2013-02-453175]

Effect of cord blood processing on transplantation outcomes after single myeloablative umbilical cord blood transplantation

Variations in cord blood manufacturing and administration are common, and the optimal practice is not known. We compared processing and banking practices at 16 public cord blood banks (CBB) in the United States and assessed transplantation outcomes on 530 single umbilical cord blood (UCB) myeloablative transplantations for hematologic malignancies facilitated by these banks. UCB banking practices were separated into 3 mutually exclusive groups based on whether processing was automated or manual, units were plasma and red blood cell reduced, or buffy coat production method or plasma reduced. Compared with the automated processing system for units, the day 28 neutrophil recovery was significantly lower after transplantation of units that were manually processed and plasma reduced (red cell replete) (odds ratio, .19; P = .001) or plasma and red cell reduced (odds ratio, .54; P = .05). Day 100 survival did not differ by CBB. However, day 100 survival was better with units that were thawed with the dextran-albumin wash method compared with the "no wash" or "dilution only" techniques (odds ratio, 1.82; P = .04). In conclusion, CBB processing has no significant effect on early (day 100) survival despite differences in kinetics of neutrophil recovery.

Different aspects of stem cell procedures in children with poor responding AML: when is HSCT the best answer?

Acute myeloid leukemia in children is a heterogeneous disease with different morphological and cytogenetic features. New diagnostic tools and treatments, improved supportive care and the use of genomic tissue typing in selecting donors for hematopoietic stem cell transplantation (HSCT) adds to increased survival rates. Candidates to HSCT in first complete remission are patients with cytogenetic or molecular unfavorable prognostic markers, or blasts >15% after first induction. The use of minimal residual disease can also identify children benefiting from HSCT in first complete remission and the patients post HSCT with signs of relapse. The outcome and cure rate of acute myeloid leukemia, still remains poor and new diagnostic tools and treatments strategies need to be evaluated. In this management perspective, future management of novel minimal residual disease tools are discussed, conditioning therapies, as well as different transplantation procedures including haplo-transplantation and haplo-identical natural killer cell transplantation, but also altered graft-versus-host-disease treatments.

Computational modeling of the expansion of human cord blood CD133+ hematopoietic stem/progenitor cells with different cytokine combinations

MOTIVATION

Many important problems in cell biology require dense non-linear interactions between functional modules to be considered. The importance of computer simulation in understanding cellular processes is now widely accepted, and a variety of simulation algorithms useful for studying certain subsystems have been designed. Expansion of hematopoietic stem and progenitor cells (HSC/HPC) in ex vivo culture with cytokines and small molecules is a method to increase the restricted numbers of stem cells found in umbilical cord blood (CB), while also enhancing the content of early engrafting neutrophil and platelet precursors. The efficacy of the expanded product depends on the composition of the cocktail of cytokines and small molecules used for culture. Testing the influence of a cytokine or small molecule on the expansion of HSC/HPC is a laborious and expensive process. We therefore developed a computational model based on cellular signaling interactions that predict the influence of a cytokine on the survival, duplication and differentiation of the CD133(+) HSC/HPC subset from human umbilical CB.

RESULTS

We have used results from in vitro expansion cultures with different combinations of one or more cytokines to develop an ordinary differential equation model that includes the effect of cytokines on survival, duplication and differentiation of the CD133(+) HSC/HPC. Comparing the results of in vitro and in silico experiments, we show that the model can predict the effect of a cytokine on the fold expansion and differentiation of CB CD133(+) HSC/HPC after 8-day culture on a 3D scaffold. Supplementary data are available at Bioinformatics online.

Blood and immune cell engineering: Cytoskeletal contractility and nuclear rheology impact cell lineage and localization: Biophysical regulation of hematopoietic differentiation and trafficking

Clinical success with human hematopoietic stem cell (HSC) transplantation establishes a paradigm for regenerative therapies with other types of stem cells. However, it remains generally challenging to therapeutically treat tissues after engineering of stem cells in vitro. Recent studies suggest that stem and progenitor cells sense physical features of their niches. Here, we review biophysical contributions to lineage decisions, maturation, and trafficking of blood and immune cells. Polarized cellular contractility and nuclear rheology are separately shown to be functional markers of a hematopoietic hierarchy that predict the ability of a lineage to traffic in and out of the bone marrow niche. These biophysical determinants are regulated by a set of structural molecules, including cytoplasmic myosin-II and nuclear lamins, which themselves are modulated by a diverse range of transcriptional and post-translational mechanisms. Small molecules that target these mechanobiological circuits, along with novel bioengineering methods, could prove broadly useful in programming blood and immune cells for therapies ranging from blood transfusions to immune attack of tumors.

Placenta-based therapies for the treatment of epidermolysis bullosa

Recessive dystrophic epidermolysis bullosa (RDEB) is a severe blistering skin disease caused by mutations in the COL7A1 gene. These mutations lead to decreased or absent levels of collagen VII at the dermal-epidermal junction. Over the past decade, significant progress has been made in the treatment of RDEB, including the use of hematopoietic cell transplantation, but a cure has been elusive. Patients still experience life-limiting and life-threatening complications as a result of painful and debilitating wounds. The continued suffering of these patients drives the need to improve existing therapies and develop new ones. In this Review, we will discuss how recent advances in placenta-based, umbilical cord blood-based and amniotic membrane-based therapies may play a role in the both the current and future treatment of RDEB.

No Synergistic Effect of Cotransplantation of MSC and Ex Vivo TPO-Expanded CD34(+) Cord Blood Cells on Platelet Recovery and Bone Marrow Engraftment in NOD SCID Mice

After cord blood (CB) transplantation, early platelet recovery in immune-deficient mice is obtained by expansion of CB CD34(+) cells with thrombopoietin (TPO) as single growth factor. Moreover, improvement of hematopoietic engraftment has been shown by cotransplantation of mesenchymal stem cells (MSC). We investigated whether a combination of both approaches would further enhance the outcome of CB transplantation in NOD SCID mice. NOD SCID mice were transplanted with either CB CD34(+) cells, CD34(+) cells with MSC, TPO-expanded CD34(+) cells or TPO-expanded CD34(+) cells with MSC. We analyzed human platelet recovery in the peripheral blood (PB) from day 4 after transplantation onward and human bone marrow (BM) engraftment at week 6. The different transplants were assessed in vitro for their migration capacity and expression of CXCR4. TPO expansion improved the early platelet recovery in the PB of the mice. Cotransplantation of MSC with CD34(+) cells improved BM engraftment and platelet levels in the PB 6 weeks after transplantation. Combining TPO expansion and MSC cotransplantation, however, neither resulted in a more efficient early platelet recovery, nor in a better BM engraftment, nor even very low or absent BM engraftment occurred. In vitro, MSC boosted the migration of CD34(+) cells, suggesting a possible mechanism for the increase in engraftment. Our results show that cotransplantation of MSC with TPO-expanded CD34(+) cells at most combines, but does not increase the separate advantages of these different strategies. A combination of both strategies even adds a risk of non engraftment.

Immunogenetic factors in the selection of cord blood units for transplantation: current search strategies and future perspectives

Hematopoietic stem cell transplantation is currently used as a curative treatment for patients with malignant and non-malignant hematologic diseases. Human leukocyte antigen (HLA) matching is a major determinant for hematopoietic stem cell transplantation outcome. For patients lacking a fully HLA-matched donor, umbilical cord blood (UCB) units are alternative sources of hematopoietic stem cells because UCB transplantation allows a less stringent HLA matching. However, selection of the optimal UCB units remains challenging. The current UCB donor selection strategies are based on both cell dose and HLA matching. This Review focuses on the immunogenetic factors that influence UCB donor selection and highlights the future perspectives in UCB donor search.

A low effective dose of interleukin-7 is sufficient to maintain cord blood T cells alive without potentiating allo-immune responses

Slow reconstitution of T cell immunity remains a critical issue after umbilical cord blood (CB) transplantation. Although this may be a consequence of the low cell dose, it may also reflect the propensity of naïve T cells, which predominate in CB, to undergo apoptotic cell death. Exogenous interleukin 7 (IL-7) can prevent apoptosis of naïve T cells, but at high concentrations, IL-7 may also expand alloreactive T cells, thereby aggravating the risk of graft-versus-host disease. We evaluated the survival of CB T cells from 34 healthy full-term pregnancies, and we found wide interdonor variation, from 17.4% to 79.7%, of CB T cells that were still alive after being rested for 4 days in culture medium without cytokine supplementation. The viability of CB T cells was negatively correlated to infant birth weight (Spearman's ρ = .376; P = .031) and positively correlated to venous CB pH (ρ = .397; P = .027); both associations were confirmed by multivariate analysis (P = .023 and P = .005, respectively). A low supplemental concentration (100 pg/mL) of recombinant human IL-7 was sufficient to maintain the viability of cryopreserved/thawed CB T cells, with most (>80%) cells remaining in a quiescent state and without significant changes in their CD4/CD8 ratio and the proportion of CD4(+) CD31(+) PTK7(+) recent thymic emigrants. IL-7 at 100 pg/mL did not lead to any significant enhancement of the alloreactive response of CB T cells, as evaluated by proliferation rates (thymidine incorporation and carboxyfluorescein diacetate succinimidyl ester dilution) and interferon-gamma production (ELISPOT). This effective concentration of IL-7 is far lower than that obtained in vivo after pharmacological administration of the cytokine. This study suggests that administration of lower doses of recombinant human IL-7 than used in previous clinical trials may be sufficient to sustain the viability of infused CB T cells and, thus, help to accelerate naïve T cell reconstitution without potentiating their alloreactivity.

CD4 T cells with effector memory phenotype and function develop in the sterile environment of the fetus

The T cell compartment is considered to be naïve and dedicated to the development of tolerance during fetal development. We have identified and characterized a population of fetally developed CD4 T cells with an effector memory phenotype (TEM), which are present in cord blood. This population is polyclonal and has phenotypic features similar to those of conventional adult memory T cells, such as CD45RO expression. These cells express low levels of CD25 but are distinct from regulatory T cells because they lack Foxp3 expression. After T cell receptor activation, neonatal TEM cells readily produced tumor necrosis factor-α (TNF-α) and granulocyte-macrophage colony-stimulating factor (GM-CSF). We also detected interferon-γ (IFN-γ)-producing T helper 1 (TH1) cells and interleukin-4 (IL-4)/IL-13-producing TH2-like cells, but not IL-17-producing cells. We used chemokine receptor expression patterns to divide this TEM population into different subsets and identified distinct transcriptional programs using whole-genome microarray analysis. IFN-γ was found in CXCR3(+) TEM cells, whereas IL-4 was found in both CXCR3(+) TEM cells and CCR4(+) TEM cells. CCR6(+) TEM cells displayed a genetic signature that corresponded to TH17 cells but failed to produce IL-17A. However, the TH17 function of TEM cells was observed in the presence of IL-1β and IL-23. In summary, in the absence of reported pathology or any major infectious history, T cells with a memory-like phenotype develop in an environment thought to be sterile during fetal development and display a large variety of inflammatory effector functions associated with CD4 TH cells at birth.

Cord blood clinical processing, cryopreservation, and storage

Allogeneic umbilical cord blood (UCB) hematopoietic stem cell transplantation has become a crucial advancement in the treatment for a variety of diseases including hematopoietic and non-hematopoietic malignancies, BM failure syndromes, hemoglobinopathies, and metabolic and immunodeficiency disorders. It has been well documented that the success of UCB engraftment is tied to UCB banking processes, and now there are established guidelines for standardization of collection, banking, processing, and cryopreservation for unrelated UCB units with purpose of achieving consistent production of high quality placental and UCB units for administration. In 2011, Canada's Ministry of Health has announced Canada's first national, publicly funded umbilical cord blood bank, which aims to provide altruistic donations for unrelated allogeneic hematopoietic stem cell transplant. In this chapter, we describe specific protocols for clinical processing, cryopreservation, and storage of UCB used by the Canadian Blood Services National Public Umbilical Cord Blood Bank.

Expansion and homing of umbilical cord blood hematopoietic stem and progenitor cells for clinical transplantation

The successful expansion of hematopoietic stem and progenitor cells (HSPCs) from umbilical cord blood (UCB) for transplantation could revolutionize clinical practice by improving transplantation-related outcomes and making available UCB units that have suboptimal cell doses for transplantation. New cytokine combinations appear able to promote HSPC growth with minimal differentiation into mature precursors and new agents, such as insulin-like growth factor-binding protein 2, are being used in clinical trials. Molecules that simulate the HSPC niche, such as Notch ligand, have also shown promise. Further improvements have been made with the use of mesenchymal stromal cells, which have made possible UCB expansion without a potentially deleterious prior CD34/CD133 cell selection step. Chemical molecules, such as copper chelators, nicotinamide, and aryl hydrocarbon antagonists, have shown excellent outcomes in clinical studies. The use of bioreactors could further add to HSPC studies in future. Drugs that could improve HSPC homing also appear to have potential in improving engraftment times in UCB transplantation. Technologies to expand HSPC from UCB and to enhance the homing of these cells appear to have attained the goal of accelerating hematopoietic recovery. Further discoveries and clinical studies are likely to make the goal of true HSPC expansion a reality for many applications in future.

Transplant physicians' perceptions of cord blood transplantation in Korea: a questionnaire survey

Background

Although bone marrow (BM) or mobilized peripheral blood (PB) is frequently used as the source of hematopoietic stem cells, hematopoietic stem cell transplantation (HSCT) using cord blood (CB) is gradually gaining popularity in many countries. However, BM or PB is still preferred over CB in Korea. Therefore, we tried to assess the awareness of CB transplantation (CBT) among domestic HSCT physicians and develop strategies for boosting its utilization by administering questionnaires to some of these physicians.

Methods

A direct questionnaire survey was conducted using the "Audience Response System" among 301 members who attended the annual meeting of the Korean Society of Blood and Marrow Transplantation. The data were analyzed for only 67 board certified physicians who were directly involved in HSCT activities.

Results

The poor outcomes resulting from insufficient experience in CBT was designated by the physicians as the main reason for the low domestic implementation of HSCT using CB. Other reasons identified in the survey were distrust in the quality and management of domestic CB and the high cost of obtaining CB.

Conclusion

Increasing the use of donated CB would foremost require increasing the inventory of donated CB containing a sufficient cell number for CBT and securing structured quality control of the CB banks. In addition, it would be necessary to minimize CB supply costs and continue to provide academic data, including CBT guidelines, so that clinicians could perform CBT with more confidence.

Using HLA typing to support patients with cancer

BACKGROUND

The human leukocyte antigen (HLA) system plays a crucial role in immune function, and HLA testing is often needed in the support of patients with cancer.

METHODS

We briefly review the published literature to clarify the nomenclature of the HLA system, currently available methods for HLA testing, and commonly used HLA assays. The uses of HLA testing in pharmacogenomics, disease association, platelet transfusion support, and in the management of both solid organ and hematopoietic stem cell transplantation are also reviewed.

RESULTS

HLA testing is commonly performed for select patient populations, including patients with cancer and in those requiring solid organ and hematopoietic stem cell transplantation.

CONCLUSION

Newer molecular typing methods have helped improve patient outcomes following hematopoietic stem cell transplantation.

Advances in umbilical cord blood manipulation-from niche to bedside

The use of umbilical cord blood (UCB) as an alternative haematopoietic cell source in lieu of bone marrow for haematopoietic reconstitution is increasingly becoming a mainstay treatment for both malignant and nonmalignant diseases, as most individuals will have at least one available, suitably HLA-matched unit of blood. The principal limitation of UCB is the low and finite number of haematopoietic stem and progenitor cells (HSPC) relative to the number found in a typical bone marrow or mobilized peripheral blood allograft, which leads to prolonged engraftment times. In an attempt to overcome this obstacle, strategies that are often based on native processes occurring in the bone marrow microenvironment or 'niche' have been developed with the goal of accelerating UCB engraftment. In broad terms, the two main approaches have been either to expand UCB HSPC ex vivo before transplantation, or to modulate HSPC functionality to increase the efficiency of HSPC homing to the bone marrow niche after transplant both of which enhance the biological activities of the engrafted HSPC. Several early phase clinical trials of these approaches have reported promising results.

A novel view of the adult bone marrow stem cell hierarchy and stem cell trafficking

This review presents a novel view and working hypothesis about the hierarchy within the adult bone marrow stem cell compartment and the still-intriguing question of whether adult bone marrow contains primitive stem cells from early embryonic development, such as cells derived from the epiblast, migrating primordial germ cells or yolk sac-derived hemangioblasts. It also presents a novel view of the mechanisms that govern stem cell mobilization and homing, with special emphasis on the role of the complement cascade as a trigger for egress of hematopoietic stem cells from bone marrow into blood as well as the emerging role of novel homing factors and priming mechanisms that support stromal-derived factor 1-mediated homing of hematopoietic stem/progenitor cells after transplantation.

Relocation of cryopreserved umbilical cord blood samples using a high-capacity dry shipper to a new laboratory: a cord blood banking experience

BACKGROUND

Processed umbilical cord blood (UCB) must be stored at cryogenic temperature at all times to maintain the quality and viability of the cells. However, a challenge is presented in the form of moving a large number of cryopreserved UCB samples to a new location. In this report, we share our experience on relocating more than 100,000 units of cryopreserved UCB samples stored in 12 liquid nitrogen freezers (LNFs) to our new laboratory.

STUDY DESIGN AND METHODS

For quality control purposes, 2 weeks before relocation, donor UCB samples were processed, cryopreserved, and stored in each LNF. On relocation day, half of the samples were retrieved to determine total nucleated cell count, percentage of CD34+ cells, and cell viability as controls for later comparison. UCB samples were transferred into dry shippers before being relocated to the new laboratory. Upon arrival, LNFs were serviced before transferring UCB samples back into its original location within the LNF. The remaining donor UCB samples were retrieved and analyzed for the same tests mentioned.

RESULTS

We found no significant differences in pre- and postrelocation values of the tests performed.

CONCLUSION

All UCB samples were successfully relocated into the new laboratory without affecting the quality.

Bone marrow regeneration promoted by biophysically sorted osteoprogenitors from mesenchymal stromal cells

Human tissue repair deficiencies can be supplemented through strategies to isolate, expand in vitro, and reimplant regenerative cells that supplant damaged cells or stimulate endogenous repair mechanisms. Bone marrow-derived mesenchymal stromal cells (MSCs), a subset of which is described as mesenchymal stem cells, are leading candidates for cell-mediated bone repair and wound healing, with hundreds of ongoing clinical trials worldwide. An outstanding key challenge for successful clinical translation of MSCs is the capacity to produce large quantities of cells in vitro with uniform and relevant therapeutic properties. By leveraging biophysical traits of MSC subpopulations and label-free microfluidic cell sorting, we hypothesized and experimentally verified that MSCs of large diameter within expanded MSC cultures were osteoprogenitors that exhibited significantly greater efficacy over other MSC subpopulations in bone marrow repair. Systemic administration of osteoprogenitor MSCs significantly improved survival rates (>80%) as compared with other MSC subpopulations (0%) for preclinical murine bone marrow injury models. Osteoprogenitor MSCs also exerted potent therapeutic effects as "cell factories" that secreted high levels of regenerative factors such as interleukin-6 (IL-6), interleukin-8 (IL-8), vascular endothelial growth factor A, bone morphogenetic protein 2, epidermal growth factor, fibroblast growth factor 1, and angiopoietin-1; this resulted in increased cell proliferation, vessel formation, and reduced apoptosis in bone marrow. This MSC subpopulation mediated rescue of damaged marrow tissue via restoration of the hematopoiesis-supporting stroma, as well as subsequent hematopoiesis. Together, the capabilities described herein for label-freeisolation of regenerative osteoprogenitor MSCs can markedly improve the efficacy of MSC-based therapies.

One-unit versus two-unit cord-blood transplantation for hematologic cancers

BACKGROUND

Umbilical-cord blood has been used as the source of hematopoietic stem cells in an estimated 30,000 transplants. The limited number of hematopoietic cells in a single cord-blood unit prevents its use in recipients with larger body mass and results in delayed hematopoietic recovery and higher mortality. Therefore, we hypothesized that the greater numbers of hematopoietic cells in two units of cord blood would be associated with improved outcomes after transplantation.

METHODS

Between December 1, 2006, and February 24, 2012, a total of 224 patients 1 to 21 years of age with hematologic cancer were randomly assigned to undergo double-unit (111 patients) or single-unit (113 patients) cord-blood transplantation after a uniform myeloablative conditioning regimen and immunoprophylaxis for graft-versus-host disease (GVHD). The primary end point was 1-year overall survival.

RESULTS

Treatment groups were matched for age, sex, self-reported race (white vs. nonwhite), performance status, degree of donor-recipient HLA matching, and disease type and status at transplantation. The 1-year overall survival rate was 65% (95% confidence interval [CI], 56 to 74) and 73% (95% CI, 63 to 80) among recipients of double and single cord-blood units, respectively (P=0.17). Similar outcomes in the two groups were also observed with respect to the rates of disease-free survival, neutrophil recovery, transplantation-related death, relapse, infections, immunologic reconstitution, and grade II-IV acute GVHD. However, improved platelet recovery and lower incidences of grade III and IV acute and extensive chronic GVHD were observed among recipients of a single cord-blood unit.

CONCLUSIONS

We found that among children and adolescents with hematologic cancer, survival rates were similar after single-unit and double-unit cord-blood transplantation; however, a single-unit cord-blood transplant was associated with better platelet recovery and a lower risk of GVHD. (Funded by the National Heart, Lung, and Blood Institute and the National Cancer Institute; ClinicalTrials.gov number, NCT00412360.).

Hematopoietic stem cell transplantation for patients with sickle cell disease: progress and future directions

Research has solidified matched sibling marrow, cord blood, or mobilized peripheral blood as the best source for allogeneic hematopoietic stem cell transplantation for patients with sickle cell disease, with low graft rejection and graft-versus-host disease (GVHD) and high disease-free survival rates. Fully allelic matched unrelated donor is an option for transplant-eligible patients without HLA-matched sibling donors. Unrelated cord transplant studies reported high GVHD and low engraftment rates. Haploidentical transplants have less GVHD, but improvements are needed to increase the low engraftment rate. The decision to use unrelated cord blood units or haploidentical donors depends on institutional expertise.

Haplo-cord transplantation using CD34+ cells from a third-party donor to speed engraftment in high-risk patients with hematologic disorders

Among the strategies to optimize engraftment of cord blood (CB) stem cell transplantation (SCT), single CB with the coinfusion of CD34(+) stem cells from an HLA-mismatched auxiliary donor (haplo-cord) provides a valid alternative for adult patients without a suitable donor. A total of 132 high-risk adult patients with hematological malignancies from 3 Spanish institutions underwent myeloablative haplo-cord SCT. The median age was 37 years and median weight was 70 kg; 37% had active disease. The median number of postprocessing CB total nucleated and CD34(+) cells was 2.4 × 10(7)/kg (interquartile range [IQR], 1.8 to 2.9) and 1.4 × 10(5)/kg (IQR, .9 to 2), respectively. Neutrophil engraftment occurred in a median of 11.5 days (IQR, 10.5 to 16.5) and platelet engraftment at 36 days (IQR, 25.5 to 77). Graft failure was 2% overall and only 9% for CB. Cumulative incidence of acute graft-versus-host disease (GHVD) grades II to IV was 21% and cumulative incidence of chronic GVHD was 21%. Median follow-up was 60 months (range, 3.5 to 163). Overall survival was 43.5%, event-free survival was 38.3%, nonrelapse mortality was 35%, and relapse was 20% at 5 years. Myeloablative haplo-cord SCT results in fast engraftment of neutrophils and platelets, low incidences of acute and chronic GVHD, and favorable long-term outcomes using single CB units with relatively low cell content. Moreover, CB cell dose had no impact on CB engraftment and survival in this study. Therefore, haplo-cord SCT expands donor availability while reducing CB cell dose requirements.

HOXA9 promotes hematopoietic commitment of human embryonic stem cells

The molecular determinants regulating the specification of human embryonic stem cells (hESCs) into hematopoietic cells remain elusive. HOXA9 plays a relevant role in leukemogenesis and hematopoiesis. It is highly expressed in hematopoietic stem and progenitor cells (HSPCs) and is downregulated upon differentiation. Hoxa9-deficient mice display impaired hematopoietic development, and deregulation of HOXA9 expression is frequently associated with acute leukemia. Analysis of the genes differentially expressed in cord blood HSPCs vs hESC-derived HSPCs identified HOXA9 as the most downregulated gene in hESC-derived HSPCs, suggesting that expression levels of HOXA9 may be crucial for hematopoietic differentiation of hESC. Here we show that during hematopoietic differentiation of hESCs, HOXA9 expression parallels hematopoietic development, but is restricted to the hemogenic precursors (HEP) (CD31(+)CD34(+)CD45(-)), and diminishes as HEPs differentiate into blood cells (CD45(+)). Different gain-of-function and loss-of-function studies reveal that HOXA9 enhances hematopoietic differentiation of hESCs by specifically promoting the commitment of HEPs into primitive and total CD45(+) blood cells. Gene expression analysis suggests that nuclear factor-κB signaling could be collaborating with HOXA9 to increase hematopoietic commitment. However, HOXA9 on its own is not sufficient to confer in vivo long-term engraftment potential to hESC-hematopoietic derivatives, reinforcing the idea that additional molecular regulators are needed for the generation of definitive in vivo functional HSPCs from hESC.

Human herpesvirus 6 reactivation before engraftment is strongly predictive of graft failure after double umbilical cord blood allogeneic stem cell transplantation in adults

Our main objective was to determine new factors associated with engraftment and single-unit predominance after double umbilical cord blood (UCB) allogeneic stem-cell transplantation. Engraftment occurred in 78% of cases in this retrospective study including 77 adult patients. Three-year overall survival, disease-free survival, relapse incidence, and nonrelapse mortality were 55 ± 6%, 44 ± 6%, 33 ± 5%, and 23 ± 4%, respectively. In multivariate analysis, Human herpesvirus 6 reactivation during aplasia (hazard ratio [HR] = 2.63; 95% confidence interval [CI]: 1.64-4.17; p < 0.001), younger recipient age (<53 years) (HR = 1.97; 95% CI: 1.16-3.35; p = 0.012), and lower human leukocyte antigen matching between the two units (3 of 6 or 4 of 6) (HR = 2.09; 95% confidence interval: 1.22-3.59; p = 0.013) were the three factors independently associated with graft failure. Also, factors independently predicting the losing UCB unit were younger age of the UCB unit (odds ratio [OR] = 1.01; 95% CI: 1-1.02; p = 0.035), lower CD34(+) cell dose contained in the UCB unit (≤ 0.8 × 10(5)/kg) (OR = 2.55; 95% CI: 1.05-6.16; p = 0.04), and presence of an ABO incompatibility between the UCB unit and the recipient (OR = 2.53; 95% CI: 1.15-5.53; p = 0.02). Thus, Human herpesvirus 6 reactivation during aplasia, lower unit-unit human leukocyte antigen matching, and younger UCB unit age, as new unfavorable predictive factors, may represent new parameters to take into account after double UCB allogeneic stem-cell transplantation in adults. These results need to be confirmed prospectively, as they may influence unit selections and patient outcomes.

Background and future considerations for human cord blood hematopoietic cell transplantation, including economic concerns

Cord blood (CB) has been used since 1988 as a source of hematopoietic stem cells (HSCs) and progenitor cells for hematopoietic cell transplantation (HCT) to treat patients with malignant and nonmalignant disorders. CB has both advantages and disadvantages when compared with other tissue sources of HSCs such as bone marrow and mobilized peripheral blood, which are also being used in the setting of HCT. This short review focuses on some historical information, as well as current efforts that are being assessed to enhance the efficacy of CB HCT. Also of importance are the costs of CB, and the feasibility and economics of using such to be identified, and newly confirmed improvements worldwide for the greatest number of patients. In this context, simple methods that would not necessarily entail the need for selected cell-processing facilities to ex vivo expand or improve the CB graft's functional activity may be of interest, with one such possibility being the use of an orally active inhibitor of the enzyme dipeptidylpeptidase 4, alone or in combination with other new and innovative approaches for improving HSC engraftment and in vivo repopulating capability of CB.

Tissue Engineering Strategies for Fetal Myelomeningocele Repair in Animal Models

Myelomeningocele (MMC), the most severe form of spina bifida, is a common and devastating malformation. Over two decades of experimental work in animal models have led to the development and clinical application of open fetal surgery for the repair of the MMC defect. This approach offers improved neurofunctional outcomes and is now a clinical option for the management of prenatally diagnosed MMC in selected patients. However, there are still opportunities for further improvement in the prenatal treatment of MMC. A less invasive approach would allow for an application earlier in gestation, with a reduction in maternal and fetal risks and the potential for reduced neurological injury. Tissue engineering offers a realistic and appealing alternative approach for the prenatal treatment of MMC. This review discusses the rationale for tissue engineering in MMC, addresses recent experimental progress and describes potential future directions.

Development of an IFN-γ ELISpot assay to assess varicella-zoster virus-specific cell-mediated immunity following umbilical cord blood transplantation

Varicella zoster virus (VZV) is a significant cause of morbidity and mortality following umbilical cord blood transplantation (UCBT). For this reason, antiherpetic prophylaxis is administrated systematically to pediatric UCBT recipients to prevent complications associated with VZV infection, but there is no strong, evidence based consensus that defines its optimal duration. Because T cell mediated immunity is responsible for the control of VZV infection, assessing the reconstitution of VZV specific T cell responses following UCBT could provide indications as to whether prophylaxis should be maintained or can be discontinued. To this end, a VZV specific gamma interferon (IFN-γ) enzyme-linked immunospot (ELISpot) assay was developed to characterize IFN-γ production by T lymphocytes in response to in vitro stimulation with irradiated live attenuated VZV vaccine. This assay provides a rapid, reproducible and sensitive measurement of VZV specific cell mediated immunity suitable for monitoring the reconstitution of VZV specific immunity in a clinical setting and assessing immune responsiveness to VZV antigens.  

Effect of CD8⁺ cell content on umbilical cord blood transplantation in adults with hematological malignancies

Total nucleated (TNCs) and CD34(+) cells are considered major determinants of outcome after umbilical cord blood (UCB) transplantation but the effect of other cell subtypes present in the graft is unknown. This single-center cohort study included patients with hematological malignancies who received UCB transplantation after a myeloablative conditioning regimen. UCB units were primarily selected according to cell content, both TNCs and CD34(+) cells, and also according to the degree of HLA matching. Counts of several cell subtypes of the infused UCB unit, together with HLA disparities and other patient- and transplantation-related characteristics, were analyzed by multivariable methodology for their association with myeloid and platelet engraftment, graft-versus-host disease, nonrelapse mortality (NRM), disease-free survival (DFS), and overall survival (OS). Two hundred patients (median age, 32 years) were included in the study. In multivariable analyses, a greater number of CD8(+) cells was significantly associated with better results for myeloid (P = .001) and platelet (P = .008) engraftment, NRM (P = .02), DFS (P = .007), and OS (P = .01). CD34(+) cell content was predictive of myeloid engraftment (P < .001). This study suggests that the outcome after UCB transplantation in adults with hematological malignancies could be better when UCB grafts had a greater CD8(+) cell content.

Umbilical cord blood banking: from personal donation to international public registries to global bioeconomy

The procedures for collecting voluntarily and freely donated umbilical cord blood (UCB) units and processing them for use in transplants are extremely costly, and the capital flows thus generated form part of an increasingly pervasive global bioeconomy. To place the issue in perspective, this article first examines the different types of UCB biobank, the organization of international registries of public UCB biobanks, the optimal size of national inventories, and the possibility of obtaining commercial products from donated units. The fees generally applied for the acquisition of UCB units for transplantation are then discussed, and some considerations are proposed regarding the social and ethical implications raised by the international network for the importation and exportation of UCB, with a particular emphasis on the globalized bioeconomy of UCB and its commerciality or lack thereof.

HLA-haploidentical transplantation with regulatory and conventional T-cell adoptive immunotherapy prevents acute leukemia relapse

Posttransplant relapse is still the major cause of treatment failure in high-risk acute leukemia. Attempts to manipulate alloreactive T cells to spare normal cells while killing leukemic cells have been unsuccessful. In HLA-haploidentical transplantation, we reported that donor-derived T regulatory cells (Tregs), coinfused with conventional T cells (Tcons), protected recipients against graft-versus-host disease (GVHD). The present phase 2 study investigated whether Treg-Tcon adoptive immunotherapy prevents posttransplant leukemia relapse. Forty-three adults with high-risk acute leukemia (acute myeloid leukemia 33; acute lymphoblastic leukemia 10) were conditioned with a total body irradiation-based regimen. Grafts included CD34(+) cells (mean 9.7 × 10(6)/kg), Tregs (mean 2.5 × 10(6)/kg), and Tcons (mean 1.1 × 10(6)/kg). No posttransplant immunosuppression was given. Ninety-five percent of patients achieved full-donor type engraftment and 15% developed ≥grade 2 acute GVHD. The probability of disease-free survival was 0.56 at a median follow-up of 46 months. The very low cumulative incidence of relapse (0.05) was significantly better than in historical controls. These results demonstrate the immunosuppressive potential of Tregs can be used to suppress GVHD without loss of the benefits of graft-versus-leukemia (GVL) activity. Humanized murine models provided insights into the mechanisms underlying separation of GVL from GVHD, suggesting the GVL effect is due to largely unopposed Tcon alloantigen recognition in bone marrow.

A novel procedure to improve functional preservation of hematopoietic stem and progenitor cells in cord blood stored at +4°c before cryopreservation

During storage and transportation of collected cord blood units (CBUs) to the bank prior to their processing and cryopreservation, it is imperative to preserve the functional capacities of a relatively small amount of cells of interest (stem and progenitor cells) which are critical for graft potency. To improve CBU storage efficiency, we conceived an approach based on the following two principles: (1) to provide a better nutritive and biochemical environment to stem and progenitor cells in CB and (2) to prevent the hyperoxygenation of these cells transferred from a low- (1.1%-4% O2 in the CB) to a high-oxygen (20%-21% O2 in atmosphere) concentration. Our hypothesis is confirmed by the functional assessment of stem cell (hematopoietic reconstitution capacity in immunodeficient mice-scid repopulating cell assay) and committed progenitor activities (capacity of in vitro colony formation and of ex vivo expansion) after the storage period with our medium (HP02) in gas-impermeable bags. This storage procedure maintains the full functional capacity of a CBU graft for 3 days with respect to day 0. Further, using this procedure, a graft stored 3 days at +4°C exhibits better functional capacities than one currently used in routine storage (CBUs stored at +4°C for 1 day in gas-permeable bags and without medium). We provided the proof of principle of our approach, developed a clinical-scale kit and performed a preclinical assay demonstrating the feasibility and efficiency of our CBU preservation protocol through all steps of preparation (volume reduction, freezing, and thawing).

Ectopic transplantation sites for cell-based therapy

PURPOSE OF REVIEW

This review outlines the concept of cell-based therapy to restore tissue function, and addresses four key points to consider in cell transplantation: source, surveillance, safety, and site. Whereas each point is essential, additional attention should be given to transplantation sites if cell therapy is going to be successful in the clinic. Various ectopic locations are discussed, and the strengths and weaknesses of each are compared as suitable candidates for cell therapy.

RECENT FINDINGS

Studies in rodents often demonstrate cell transplantation and engraftment in ectopic sites, with little evidence to suggest why it may also work in humans. For example, transplantation to the subcapsular space of the kidney is often performed in rodents, but has not been a good predictor of clinical success. Recent work has shown that the lymph node may be a good site for transplantation of multiple tissue types, and several reasons are highlighted as to why it should be considered for future studies.

SUMMARY

The use of cell-based therapy in the clinic has been hampered by the lack of appropriate sites for transplantation. The lymph node is a promising alternative for cell transplantation, and offers hope for clinical application.

The skinny on obesity and plasma cell myeloma: a review of the literature

Despite tremendous advances in treatments for myeloma in the past decade, the disease remains incurable in the majority of patients. Here, we review recent data demonstrating an association between obesity and increased risk of myeloma development. This may be due to the pro-inflammatory cytokine profile caused by obesity. Currently, there are no screening or prevention strategies for myeloma, but we propose that obesity-associated inflammatory pathways, or obesity itself, may be amenable to intervention, thereby preventing the transition from pre-malignancy to myeloma. In addition, we suggest that the morbidity, mortality and the significant costs associated with myeloma treatment could be reduced by addressing modifiable risk factors, and that research efforts should explore this novel hypothesis.

Optimization of the viability of stem cells derived from umbilical cord blood after maternal supplementation with DHA during the second or third trimester of pregnancy: study protocol for a randomized controlled trial

BACKGROUND

Umbilical cord blood (UCB) is an important source of hematopoietic stem cells (HSCs). However, the concentration of cells in cord blood units is limited and this may represent the main restriction to their therapeutic clinical use. The percentage of metabolically active stem cells provides a measure of the viability of cells in an UCB sample. It follows that an active cellular metabolism causes a proliferation in stem cells, offering an opportunity to increase the cellular concentration. A high cell dose is essential when transplanting cord stem cells, guaranteeing, in the receiving patient, a successful outcome.This study is designed to evaluate the impact of docosahexaenoic acid (DHA) supplementation in pregnant women, in order to increase the quantity and viability of the cells in UCB samples.

METHODS/DESIGN

The metabolic demand of DHA increases in the course of pregnancy and reaches maximum absorption during the third trimester of pregnancy. According to these observations, this trial will be divided into two different experimental groups: in the first group, participants will be enrolled from the 20th week of estimated stage of gestation, before the maximum absorption of DHA; while in the second group, enrolment will start from the 28th week of estimated stage of gestation, when the DHA request is higher. Participants in the trial will be divided and randomly assigned to the placebo group or to the experimental group. Each participant will receive a complete set of capsules of either placebo (250 mg of olive oil) or DHA (250 mg), to take one a day from the 20th or from the 28th week, up to the 40th week of estimated gestational age. Samples of venous blood will be taken from all participants before taking placebo or DHA, at the 20th or at the 28th week, and at the 37th to 38th week of pregnancy to monitor the level of DHA. Cell number and cellular viability will be evaluated by flow cytometry within 48 hours of the UCB sample collection.

TRIAL REGISTRATION

International Standard Randomised Controlled Trial Number Register: ISRCTN58396079. Registration date: 8 October 2013.

Epithelial and Mesenchymal Stem Cells from the Umbilical Cord Lining Membrane

Intense scientific research over the past two decades has yielded much knowledge about embryonic stem cells, mesenchymal stem cells from bone marrow, as well as epithelial stem cells from the skin and cornea. However, the billions of dollars spent in this research have not overcome the fundamental difficulties intrinsic to these stem cell strains related to ethics (embryonic stem cells), as well as to technical issues such as accessibility, ease of cell selection and cultivation, and expansion/mass production, while maintaining consistency of cell stemness (all of the stem cell strains already mentioned). Overcoming these technical hurdles has made stem cell technology expensive and any potential translational products unaffordable for most patients. Commercialization efforts have been rendered unfeasible by this high cost. Advanced biomedical research is on the rise in Asia, and new innovations have started to overcome these challenges. The Nobel Prize-winning Japanese development of iPSCs has effectively introduced a possible replacement for embryonic stem cells. For non-embryonic stem cells, cord lining stem cells (CLSCs) have overcome the preexisting difficulties inherent to mesenchymal stem cells from the bone marrow as well as epithelial stem cells from the skin and cornea, offering a realistic, practical, and affordable alternative for tissue repair and regeneration. This novel CLSC technology was developed in Singapore in 2004 and has 22 international patents granted to date, including those from the US and UK. CLSCs are derived from the umbilical cord outer lining membrane (usually regarded as medical waste) and is therefore free from ethical dilemmas related to its collection. The large quantity of umbilical cord lining membrane that can be collected translates to billions of stem cells that can be grown in primary stem cell culture and therefore very rapid and inexpensive cell cultivation and expansion for clinical translational therapies. Both mesenchymal and epithelial stem cells can be isolated from the umbilical cord lining membrane, usefully regenerating not only mesenchymal tissue, such as bone, cartilage, and cardiac and striated muscle, but also epithelial tissue, such as skin, cornea, and liver. Both mesenchymal and epithelial CLSCs are immune privileged and resist rejection. Clinically, CLSCs have proved effective in the treatment of difficult-to-heal human wounds, such as diabetic ulcers, recalcitrant chronic wounds, and even persistent epithelial defects of the cornea. Heart and liver regeneration has been shown to be successful in animal studies and await human trials. CLSCs have also been shown to be an effective feeder layer for cord blood hematopoietic stem cells and, more recently, has been recognized as an abundant and high-quality source of cells for iPSC production. Banking of CLSCs by cord blood banks in both private and public settings is now available in many countries, so that individuals may have their personal stores of CLSCs for future translational applications for both themselves and their families. Cord lining stem cells are strongly positioned to be the future of cell therapy and regenerative medicine.

Inhibiting HDAC for human hematopoietic stem cell expansion

In this issue of the JCI, Chaurasia and colleagues report an impressive ex vivo expansion of HSCs from human cord blood (CB) using cytokines and altering epigenetic modifications. The application of this protocol provides information that has potential for clinical consideration. The enhanced expansion of CB HSCs is a substantial advance over recent work from the Chaurasia and Hoffman group, in which ex vivo production of human erythroid progenitor cells from CB was promoted by chromatin modification. Moreover, this study takes advantage of information from the rapidly emerging, but not yet fully elucidated, field of epigenetics.

A critical review of which children with acute myeloid leukaemia need stem cell procedures

The last decades have seen parallel improvements in chemotherapy-based and haematopoietic stem cell transplantation (HSCT) regimens for acute myeloid leukaemia (AML) in children. There has been no consensus on indication for HSCT. Reserving HSCT for high-risk and relapsed patients spare many patients from the long-term toxicity of this treatment. The results of matched unrelated donor HSCT equal family donor transplantation and the presence of a matched sibling should no longer be a transplant indication. Minimal residual disease measured by flow cytometry may identify poor responders benefitting from HSCT in first complete remission (CR1) and those with a favourable response to induction therapy who do not need HSCT even with adverse cytogenetic aberrations. FLT3-internal tandem duplication without NPM1 mutation has a very high relapse rate despite favourable response and HSCT is indicated in CR1 in these cases. Finding the optimal indications for HSCT is a delicate balance between risk of relapse and late effects.

A novel reduced-intensity umbilical cord blood transplantation using a recombinant G-CSF combined with high-dose Ara-C for active myeloid malignancies

Non-remitting patients with hematologic myeloid malignancies have poor prognosis. To overcome this problem, we investigated the use of reduced-intensity preconditioning umbilical cord blood transplantation (RICBT) combined with recombinant G-CSF (rG-CSF) with high-dose Ara-C, fludarabine, melphalan, and 4 Gy of TBI in a phase I/II study in patients with non-remitting myeloid hematologic malignancies. Thirteen patients were enrolled, including 12 with non-remitting AML and one patient with blastic crisis CML (CML-BC). The patients' median age was 45 years, with a median comorbidity index of 4. All patients received 4/6 serological HLA-antigen matched unrelated umbilical cord blood. All patients were engrafted within 30 days after RICBT (median, 20 days; range, 14-29) and achieved complete remission without prior hematopoiesis. Common grade III non-hematologic toxicities included eight cases of transient mucositis (62%) and six cases of febrile neutropenia (46%). Transplant-related mortality was 7.7%. The 1-year overall survival was 28.6% in cases without post-RICBT treatment and 83.3% in cases with post-RICBT treatment. These data suggest that in active AML and CML-BC, the combination of rG-CSF with high-dose Ara-C and fludarabine/melphalan/4 Gy TBI with a reduced-intensity preconditioning regimen is well tolerated, secures engraftment and has significant anti-leukemia activity. In addition, performing post-RICBT treatment may provide high-quality long-term survival and remission.

Cord blood banking and transplantation: advances and controversies

PURPOSE OF REVIEW

A review of articles published since January 2012 on the topic of cord blood banking and cord blood stem cell transplantation was conducted for this the 25th anniversary year of the first cord blood transplant performed in a human.

RECENT FINDINGS

Cord blood banking is performed throughout the world. Umbilical cord blood (UCB) transplantation is recognized as an acceptable alternative stem cell source for paediatric and adults requiring a haematopoietic transplant, particularly for patients of racial and ethnic minorities. To further advance the use of UCB, methods to enhance UCB stem cell expansion, engraftment and maintenance may be required. Controversy on the most effective and economically sustainable model for banking and storing an optimal UCB product continues to persist.

SUMMARY

Cord blood banking and transplantation of cord blood stem cells has advanced rapidly over the initial 25 years, as more than 30 ,000 patients have benefited from the therapy. New concepts on the use of methods to expand UCB stem cells for transplantation and use for nonhaematopoietic indications may increase demand for UCB over the next few decades.

Concise review: next-generation cell therapies to prevent infections in neutropenic patients

High-dose chemotherapy is accompanied by an obligate period of neutropenia. Resulting bacterial and fungal infections are the leading cause of morbidity and mortality in neutropenic patients despite prophylactic antimicrobials and hematopoietic growth factor supplements. Replacing neutrophils in the patient through transfusion of donor cells is a logical solution to prevent fulminant infections. In the past, this strategy has been hampered by poor yield, inability to store collected cells, and possible donor morbidity caused by granulocyte colony-stimulating factor injections and apheresis. Today, neutrophil-like cells can be manufactured in the laboratory at the clinical scale from hematopoietic stem and progenitor cells enriched from umbilical cord blood. This article reviews the rationale for focusing research efforts toward ex vivo neutrophil production and explores clinical settings for future trials.

Inhibition of DPP4/CD26 and dmPGE₂ treatment enhances engraftment of mouse bone marrow hematopoietic stem cells

Enhancing the engraftment of hematopoietic stem cells (HSC) is especially important when times to engraftment are prolonged due either to limiting numbers of HSC in the donor graft or to intrinsic slower engrafting time of the tissue sources of HSC. Both inhibition of dipeptidylpeptidase (DPP) 4/CD26 and treatment of cells with 16,16 dimethyl prostaglandin E2 (dmPGE2) have been shown to enhance hematopoietic stem cell engraftment in murine transplantation models and have been evaluated in clinical settings for their influence on engraftment of cord blood cells, a tissue source of HSC known to manifest an extended time to engraftment of donor cells compared to that of bone marrow (BM) and mobilized peripheral blood for hematopoietic cell transplantation (HCT). Herein, we present new experimental data, using a CD45(+) head-to-head congenic model of donor mouse BM cells for engraftment of lethally irradiated mice, demonstrating that similar levels of enhanced engraftment are detected by pulsing donor BM cells with diprotin A, a DPP4 inhibitor, or with dmPGE2 prior to infusion, or by pretreating recipient mice with sitagliptin, also a DPP4 inhibitor, by oral gavage. Moreover, the combined effects of pretreating the donor BM cells with dmPGE2 in context of pretreating the recipient mice with sitagliptin after the administration of a lethal dose of radiation resulted in significantly enhanced competitively repopulating HCT compared to either treatment alone. This information is highly relevant to the goal of enhancing engraftment in human clinical HCT.

Modelling the sitagliptin effect on dipeptidyl peptidase-4 activity in adults with haematological malignancies after umbilical cord blood haematopoietic cell transplantation

BACKGROUND AND OBJECTIVES

Dipeptidyl peptidase-4 (DPP4) inhibition is a potential strategy to increase the engraftment rate of haematopoietic stem/progenitor cells. A recent clinical trial using sitagliptin, a DPP4 inhibitor approved for type 2 diabetes mellitus, has been shown to be a promising approach in adults with haematological malignancies after umbilical cord blood (UCB) haematopoietic cell transplantation (HCT). On the basis of data from this clinical trial, a semi-mechanistic model was developed to simultaneously describe DPP4 activity after multiple doses of sitagliptin in subjects with haematological malignancies after a single-unit UCB HCT.

METHODS

The clinical study included 24 patients who received myeloablative conditioning followed by oral sitagliptin with single-unit UCB HCT. Using a nonlinear mixed-effects approach, a semi-mechanistic pharmacokinetic-pharmacodynamic model was developed to describe DPP4 activity from these trial data, using NONMEM version 7.2 software. The model was used to drive Monte Carlo simulations to probe the various dosage schedules and the attendant DPP4 response.

RESULTS

The disposition of sitagliptin in plasma was best described by a two-compartment model. The relationship between sitagliptin concentrations and DPP4 activity was best described by an indirect response model with a negative feedback loop. Simulations showed that twice daily or three times daily dosage schedules were superior to a once daily schedule for maximal DPP4 inhibition at the lowest sitagliptin exposure.

CONCLUSION

This study provides the first pharmacokinetic-pharmacodynamic model of sitagliptin in the context of HCT, and provides a valuable tool for exploration of optimal dosing regimens, which are critical for improving the time to engraftment in patients after UCB HCT.