The homeobox transcription factor HB9 induces senescence and blocks differentiation in hematopoietic stem and progenitor cells.

The homeobox gene HLXB9 encodes for the transcription factor HB9, which is essential for pancreatic as well as motor neuronal development. Beside its physiological expression pattern, aberrant HB9 expression has been observed in several neoplasias. Especially in infant translocation t(7;12) acute myeloid leukemia, aberrant HB9 expression is the only known molecular hallmark and is assumed to be a key factor in leukemic transformation. However, so far, only poor functional data exist addressing the oncogenic potential of HB9 or its influence on hematopoiesis. We investigated the influence of HB9 on cell proliferation and cell cycle in vitro, as well as on hematopoietic stem cell differentiation in vivo using murine and human model systems. In vitro, HB9 expression led to premature senescence in human HT1080 and murine NIH3T3 cells, providing for the first time evidence for an oncogenic potential of HB9. Onset of senescence was characterized by induction of the p53-p21 tumor suppressor network, resulting in growth arrest, accompanied by morphological transformation and expression of senescence-associated ß-galactosidase. In vivo, HB9-transduced primary murine hematopoietic stem and progenitor cells underwent a profound differentiation arrest and accumulated at the megakaryocyte/erythrocyte progenitor stage. In line, gene expression analyses revealed de novo expression of erythropoiesis-related genes in human CD34+hematopoietic stem and progenitor cells upon HB9 expression. In summary, the novel findings of HB9-dependent premature senescence and myeloid-biased perturbed hematopoietic differentiation, for the first time shed light on the oncogenic properties of HB9 in translocation t(7;12) acute myeloid leukemia.

Impact of cord blood banking technologies on clinical outcome: a Eurocord/Cord Blood Committee (CTIWP), European Society for Blood and Marrow Transplantation and NetCord retrospective analysis.

BACKGROUND: Techniques for banking cord blood units (CBUs) as source for hematopoietic stem cell transplantation have been developed over the past 20 years, aimed to improve laboratory efficiency without altering the biologic properties of the graft. A large-scale, registry-based assessment of the impact of the banking variables on the clinical outcome is currently missing. STUDY DESIGN AND METHODS: A total of 677 single cord blood transplants (CBTs) carried out for acute leukemia in complete remission in centers affiliated with the European Society for Blood and Marrow Transplantation were selected. An extensive set of data concerning CBU banking were collected and correlations with clinical outcome were assessed. Clinical endpoints were transplant-related mortality, engraftment, and graft-versus-host disease (GVHD). RESULTS: The median time between collection and CBT was 4.1 years (range, 0.2-16.3 years). Volume reduction (VR) of CBUs before freezing was performed in 59.2% of available reports; in half of these the frozen volume was less than 30 mL. Cumulative incidences of neutrophil engraftment on Day 60, 100-day acute GVHD (II-IV), and 4-year chronic GVHD were 87, 29, and 21 ± 2%. The cumulative incidence of nonrelapse mortality (NRM) at 100 days and 4-year NRM were, respectively, 16 ± 2 and 30 ± 2%. Neither the variables related to banking procedures nor the interval between collection and CBT influenced the clinical outcome. CONCLUSION: These findings indicate a satisfactory validation of the techniques associated with CBU VR across the banks. Cell viability assessment varied among the banks, suggesting that efforts to improve the standardization of CBU quality controls are needed.

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.

Effect of HLA-matching recipients to donor noninherited maternal antigens on outcomes after mismatched umbilical cord blood transplantation for hematologic malignancy.

Transplantation-related mortality (TRM) is high after HLA-mismatched umbilical cord blood (UCB) transplantation (UCBT). In utero, exposure to noninherited maternal antigen (NIMA) is recognized by the fetus, which induces T regulator cells to that haplotype. It is plausible that UCBTs in which recipients are matched to donor NIMAs may alleviate some of the excess mortality associated with this treatment. To explore this concept, we used marginal matched-pair Cox regression analysis to compare outcomes in 48 NIMA-matched UCBTs (ie, the NIMA of the donor UCB unit matched to the patient) and in 116 non-NIMA-matched UCBTs. All patients had a hematologic malignancy and received a single UCB unit. Cases and controls were matched on age, disease, disease status, transplantation-conditioning regimen, HLA match, and infused cell dose. TRM was lower after NIMA-matched UCBTs compared with NIMA-mismatched UCBTs (relative risk, 0.48; P = .05; 18% versus 32% at 5 years posttransplantation). Consequently, overall survival was higher after NIMA-matched UCBT. The 5-year probability of overall survival was 55% after NIMA-matched UCBTs versus 38% after NIMA-mismatched UCBTs (P = .04). When faced with the choice of multiple HLA-mismatched UCB units containing adequate cell doses, selecting an NIMA-matched UCB unit may improve survival after mismatched UCBT.

Effect of donor-recipient HLA matching at HLA A, B, C, and DRB1 on outcomes after umbilical-cord blood transplantation for leukaemia and myelodysplastic syndrome: a retrospective analysis.

BACKGROUND: The importance of matching at the HLA C locus has not been well defined for unrelated umbilical-cord blood transplantation. The selection algorithm for umbilical-cord blood units generally considers intermediate resolution HLA typing at A and B and allele-level typing at DRB1. We aimed to establish the relative importance of additional matching at HLA C. METHODS: We used Cox regression to assess retrospectively the effect of donor-recipient HLA matching on outcomes of single umbilical-cord blood transplantations for leukaemia and myelodysplastic syndrome. Our primary endpoint was transplant-related mortality. HLA typing was done with molecular techniques with a minimum of intermediate resolution for HLA A, B, and C, and at the allele-level for DRB1. FINDINGS: The median age of our study population was 10 years (range <1-62) and 552 (69%) of 803 patients were aged 16 years or younger at transplantation. Compared with transplantations matched at HLA A, B, C, and DRB1 (n=69), transplant-related mortality risk was higher after transplantations matched at HLA A, B, and DRB1 and mismatched at HLA C (n=23; HR 3·97, 95% CI 1·27-12·40; p=0·018). Transplant-related mortality risk was also higher after transplantations with a single mismatch at HLA A, B, or DRB1 and mismatched at HLA C (n=234; 1·70, 1·06-2·74; p=0·029) compared with transplantations matched at HLA C with a single mismatch at HLA A, B, or DRB1 (n=127). Assessing the overall effect of HLA disparity on transplant-related mortality, risks were higher with units mismatched at two (n=259; 3·27, 1·42-7·54; p=0·006), three (n=253; 3·34, 1·45-7·71; p=0·005), or four (n=75; 3·51, 1·44-8·58; p=0·006) loci compared with matched units (n=69). INTERPRETATION: Our data suggest that the present strategy for umbilical-cord blood unit selection should be reassessed; matching at HLA C for units that are matched at HLA A, B, or DRB1 or in the presence of a single locus mismatch at HLA A, B, or DRB1 should be included to minimise mortality risks. FUNDING: National Cancer Institute, National Heart Lung and Blood Institute, National Institute for Allergy and Infectious Diseases, Leukemia and Lymphoma Society, US Department of the Navy, Children's Leukemia Research Association, and INSERM.

Human leukocyte antigen matching in cord blood transplantation.

Cord blood transplants are now widely used for allogeneic hematopoietic stem cell transplants (HSCT) in patients with various hematologic disorders. One advantage of this source of stem cells is the decrease of graft-versus-host disease (GVHD) because of the immaturity of lymphocytes at birth. The role of human leukocyte antigen (HLA) for donor search and post-transplant outcomes is not very well described. The Eurocord Registry has analyzed more than 1,000 cases of unrelated cord blood transplants (UCBT). Results show that HLA matching is important for engraftment and graft versus leukemia but not for survival and GVHD. Allelic matching for HLA-A, -B, -C, -DRB1, and -DQB1 shows that the number of mismatches is very high and does not allow identification of prognostic factors. Contrary to the criteria of donor choice for an unrelated bone marrow transplant where HLA allelic matching is important, in the case of cord blood transplants the number of nucleated cells infused is the most important predictor of success.

Factors associated with outcomes of unrelated cord blood transplant: guidelines for donor choice.

OBJECTIVE: Optimizing cord blood donor selection based mainly on cell dose and human leukocyte antigen (HLA) disparities may further improve results of unrelated cord blood transplants (UCBT). MATERIALS AND RESULTS: We analyzed 550 UCBTs for hematologic malignancies reported to the Eurocord Registry. Main outcomes and prognostic factors were analyzed in univariable and multivariable analyses incorporating center and period effects and using death and relapse as competitive risks for nonfatal endpoints. Nucleated cell (NC) dose before freezing and number of HLA disparities had a significant influence on outcome. Cumulative incidence (CI) of neutrophil and platelet recovery was associated with the number of HLA mismatches, number of NC before freezing, and use of granulocyte colony-stimulating factor. Coexistence of HLA class I and II disparities and high CD34 cell dose in the graft were associated with graft-vs-host disease grades III-IV. CI of disease relapse was higher in matched transplants showing a graft-vs-leukemia effect increased in HLA-mismatched transplants. Overall 3-year survival was 34.4%. Prognostic factors for survival were recipient age, gender, and disease status. CONCLUSION: Our results provide indications for a better choice of cord blood units according to cord blood cell content and HLA.

Comparison of application systems for autologous serum eye drops.

PURPOSE: Autologous serum eye drops are used for therapy of severe ocular surface disorders by patients with visual and manual impairments. Until recently, they were prepared under sterile conditions from open blood sampling systems. Closed blood donation systems simplify production. This study compares handling and costs of a new day dosage vial ("Meise-vial") and a single-dose tube system ("Maco-tube") based on closed production systems with conventional dropper bottles. METHODS: Nonimpaired volunteers and patients with visual or manual impairment (n = 10 each group) single-handedly tested the applicators filled with 1.5 ml sterile isotonic saline solution. Participants rated convenience of opening the containers and applying eye drops on a scale from 1.0 (very good) to 6.0 (very bad). Number of retrievable drops was counted. Participants were asked which system they prefer, both with and without knowledge of the price for the systems. RESULTS: The median for convenience of opening (eye drop application) was 2.0 (1.0) for Meise-vials, 5.0 (4.0) for Maco-tubes, and 2.0 (2.0) for dropper bottles (p < 0.001). Median number of drops retrieved from the systems was 30.5 (vials), 2 (tubes), and 30 (bottles). Ranking did not differ between nonimpaired and impaired participants. Assuming equal prices, 16 participants chose Meise-vials, 14 dropper bottles, and no tubes. With knowledge of pricing, preference changed (p = 0.001), 20 participants (67%) opted for dropper bottles and 5 (17%) preferred the other containers. CONCLUSION: Convenience of opening, applying eye drops, and number of drops retrieved was substantially better for dropper bottles and Meise-vials compared with Maco-tubes. Bottles and vials were equally well received. With regard to price, nonimpaired as well as impaired participants preferred dropper bottles. While closed systems simplify production, patients preferred dropper bottles for daily application of autologous serum eye drops for a number of reasons.

Magnetically guided recellularization of decellularized stented porcine pericardium-derived aortic valve for TAVI.

Application of somatic stem cells for growth, proliferation, and differentiation in a three-dimensional pattern is an important aspect in tissue engineering. Here, we report on our bioreactor, which we applied for magnetically guided recellularization of nitinol-stented valve. Human-derived unrestricted somatic stem cells were cultured in medium in our pulsatile dynamic bioreactor for 4-6 days. Stented valves were prepared by decellularization of porcine pericardium and construction of stented tissue-engineered valves (n = 8). A magnetic field was created around the bioreactor to prevent the loss of cells. In the control group, no magnetic device was used (n = 4). Morphological characterization was assessed by immunohistochemical staining of paraffin sections and electron microscopy. The bioreactor enabled the preservation of physiologic culture conditions with aerobic cell metabolism and physiological pH values. Histological analysis showed homogeneous seeding of the pericardium with progenitor cells in the recellularized samples, whereas no cell seeding could be observed in the nonmagnetic group. Our magnetically guided multifunctional bioreactor allows for an efficient three-dimensional culturing of somatic stem cells on decellularized organ-specific matrix.

Unrestricted somatic stem cells (USSC) from human umbilical cord blood display uncommitted epigenetic signatures of the major stem cell pluripotency genes.

Unrestricted somatic stem cells (USSC) from human cord blood display a broad differentiation potential for ectodermal, mesodermal, and endodermal cell types. The molecular basis for these stem cell properties is unclear and unlike embryonic stem cells (ESC) none of the major stem cell factors OCT4, SOX2, and NANOG exhibits significant expression in USSC. Here, we report that these key stem cell genes hold an epigenetic state in between that of an ESC and a terminally differentiated cell type. DNA methylation analysis exhibits partial demethylation of the regulatory region of OCT4 and a demethylated state of the NANOG and SOX2 promoter/enhancer regions. Further genome-wide DNA methylation profiling identified a partially demethylated state of the telomerase gene hTERT. Moreover, none of the pluripotency factors exhibited a repressive histone signature. Notably, SOX2 exhibits a bivalent histone signature consisting of the opposing histone marks dimeH3K4 and trimeH3K27, which is typically found on genes that are "poised" for transcription. Consequently, ectopic expression of OCT4 in USSC led to rapid induction of expression of its known target gene SOX2. Our data suggest that incomplete epigenetic repression and a "poised" epigenetic status of pluripotency genes preserves the USSC potential to be able to react adequately to distinct differentiation and reprogramming cues.