Effects of MSC coadministration and route of delivery on cord blood hematopoietic stem cell engraftment.

Hematopoietic stem cell transplantation (HSCT) using umbilical cord blood (UCB) progenitors is increasingly being used. One of the problems that may arise after UCB transplantation is an impaired engraftment. Either intrabone (IB) injection of hematopoietic progenitors or mesenchymal stem cell (MSC) coadministration has been proposed among the strategies to improve engraftment. In the current study, we have assessed the effects of both approaches. Thus, NOD/SCID recipients were transplanted with human UCB CD34+ cells administered either intravenously (IV) or IB, receiving or not bone marrow (BM)-derived MSCs also IV or IB (in the right femur). Human HSC engraftment was measured 3 and 6 weeks after transplantation. Injected MSCs were tracked weekly by bioluminescence. Also, lodgment within the BM niche was assessed at the latter time point by immuno-fluorescence. Our study shows regarding HSC engraftment that the number of BM human CD45+ cells detected 3 weeks after transplantation was significantly higher in mice cotransplanted with human MSCs. Moreover, these mice had a higher myeloid (CD13+) engraftment and a faster B-cell (CD19+) chimerism. At the late time point evaluated (6 weeks), human engraftment was higher in the group in which both strategies were employed (IB injection of HSC and MSC coadministration). When assessing human MSC administration route, we were able to track MSCs only in the injected femurs, whereas they lost their signal in the contralateral bones. These human MSCs were mainly located around blood vessels in the subendosteal region. In summary, our study shows that MSC coadministration can enhance HSC engraftment in our xenogenic transplantation model, as well as IB administration of the CD34+ cells does. The combination of both strategies seems to be synergistic. Interestingly, MSCs were detected only where they were IB injected contributing to the vascular niche.

Both expanded and uncultured mesenchymal stem cells from MDS patients are genomically abnormal, showing a specific genetic profile for the 5q- syndrome.

The presence of cytogenetic aberrations on mesenchymal stem cells (MSC) from myelodysplastic syndrome (MDS) patients is controversial. The aim of the study is to characterize bone marrow (BM) derived MSC from patients with MDS using: kinetic studies, immunophenotyping, fluorescent in situ hybridization (FISH) and genetic changes by array-based comparative genomic hybridization (array-CGH). In all 36 cases of untreated MDS were studied. MDS-MSC achieved confluence at a significantly slower rate than donor-MSC, and the antigenic expression of CD105 and CD104 was lower. Array-CGH studies showed DNA genomic changes that were proved not to be somatic. These results were confirmed by FISH. To confirm that genomic changes were also present in freshly obtained MSCs they were enriched by sorting BM cells with the following phenotype: CD45(-)/CD73(++)/CD34(-)/CD271(++). They also showed genomic changes that were confirmed by FISH. To analyze the relationship of these aberrations with clinical-biological data an unsupervised hierarchical cluster analysis was performed, two clusters were identified: the first one included the 5q- syndrome patients, whereas the other incorporated other MDS. Our results show, for the first time that MSC from MDS display genomic aberrations, assessed by array-CGH and FISH, some of them specially linked to a particular MDS subtype, the 5q- syndrome.

In leukapheresis products from non-Hodgkin's lymphoma patients, the immature hematopoietic progenitors show higher CD90 and CD34 antigenic expression.

Damage to the stem cell progenitors caused by the chemotherapy received in patients diagnosed with non-Hodgkin's lymphoma (NHL) may be an important factor limiting progenitor cell mobilization. The aim of the present analysis was to evaluate the effect of the chemotherapy on the different progenitor cell subpopulations obtained in the leukapheresis. For this purpose, a combination of immunophenotype and functional assays has been performed in 26 mobilized peripheral blood (PB) samples from NHL patients and 36 healthy donors. The different progenitor subpopulations analyzed by flow cytometry significantly correlated with the corresponding populations assessed by functional assays in both healthy donors and NHL patients (p<0.05, r>0.5). The number of committed CFU-GM was similar in both groups (p=0.246), but we found significant decrease in the number of BFU-E and more immature progenitors in PB from NHL patients as compared to donors (p<0.05). Moreover, the number of total CFU was significantly lower in NHL patients (p=0.007). Accordingly, CD34+ cells (p=0.018) and CD34+ subpopulations was decreased in NHL patients. Nevertheless, CD90 and CD34 intensity was significantly higher within CD34+ cells from NHL patients as compared to donors. However, although numerically reduced non-committed CD34+ cells are more immature in chemotherapy mobilized NHL patients. In summary, our results show that all NHL hematopoietic progenitors, analyzed by both immunophenotypical and functional approaches, are impaired in leukapheresis products.

Short-term endothelial progenitor cell colonies are composed of monocytes and do not acquire endothelial markers.

BACKGROUND: The aim of this study was to identify circulating endothelial progenitor cells (EPC) with colony-forming capacity and compare them with the monocytic-macrophage lineage. METHODS: Forty-two healthy donors were analyzed. EPC were cultured with VEGF and b-FGF. Sequential studies were performed on days +7 (colonies) +21 and +35. Monocytic cells were cultured using the same conditions as EPC until day +21 or alternatively by adding IGF. RESULTS: The number of EPC colonies was higher in BM than in mobilized or steady-state PB. Using EPC medium, monocytic cells formed cord-like structures but no colonies. However, colonies grew when IGF was added to the medium. By immunocytochemistry, colonies showed CD45, CD31 and lysozyme but no vWF. Colonies were CD4+, CD13+dim, CD14+, CD15++, CD16-/+dim, CD31+dim, CD33+dim, CD45+, CD105-/+dim, lysozyme+ and VE-cadherin+, and constantly negative for CD34, CD133 and KDR, when flow cytometry was used. The immunophenotype of pre-cultured and cultured monocytes was similar to that described for EPC. DISCUSSION: Our results suggest that the so-called 'EPC' obtained at 7 days of culture belong to the monocyte-macrophage lineage, as they share immunophenotypic and molecular features.

Peripheral endothelial progenitor cells (CD133 +) for therapeutic vasculogenesis in a patient with critical limb ischemia. One year follow-up.

We present a patient with critical limb ischemia who was successfully treated with the injection of autologous peripheral blood (PB) CD133+ purified stem cells (SC) into the gastrocnemius muscle. No serious adverse events related to G-CSF administration, mononuclear cells harvest or CD133+ SC administration was observed. After 17 months of follow-up, our patient has experienced limb salvage, symptomatic relief and functional improvement. Moreover, we have observed the appearance of flow in the right posterior tibial artery that was absent before the procedure. To our knowledge, this is the first case of critical limb ischemia treated with PB CD133+ SC.

Results of autologous transplantation in lymphoma are not improved by increasing the dose of etoposide in the BEAM regimen: a single-centre sequential-cohort study.

We have undertaken a retrospective sequential-cohort analysis of 131 lymphoma patients treated with the BEAM regimen and autologous stem cell transplantation, to compare BEAM at standard doses (sBEAM; n = 67 from May 1990 to April 1995) and BEAM with escalated etoposide dose from 800 to 1600 mg/m(2) (eBEAM; n = 64 from May 1995 to June 1999). Transplant-related mortality and incidence of secondary malignancies were similar in both groups. Disease progression was significantly lower in indolent lymphoma (IL) patients receiving eBEAM (7 vs 43%), although survival was comparable due to a higher toxic mortality in the eBEAM group. The 5-year event-free survival and overall survival were better in Hodgkin's disease (HD) patients treated with eBEAM (70 and 77%, respectively) compared to sBEAM (58 and 69%, respectively), but the difference was not statistically significant. In aggressive lymphomas, no difference was detected between groups. Our results indicate that while escalation of the etoposide doses in the BEAM conditioning regimen does not appear to improve outcome, encouraging results in IL and HD may warrant further studies.

[Long-term culture: evidence of the capacity of stroma to sustain hematopoiesis of a second inoculum]. / Cultivo a largo plazo: evidencia de la capacidad del estroma para sustentar la hematopoyesis de un segundo inóculo.

PURPOSE: To analyze, in two-stages long term bone marrow cultures (LTBMC), the efficiency of the method used for irradiation of the stroma and to check if after that, it's capable to support the hematopoiesis. MATERIAL AND METHODS: We have used for the first inoculum, bone marrow cells from eight controls. They were cultured at 2 x 10(6) cells/ml concentration until obtaining a fully confluent stroma which was irradiated with 15 Gy. After that, over this layer, we put a second inoculum with bone marrow cells in four cases, and with peripheral blood cells in four others, at a concentration of 1 x 10(5) cells/mL. In four cases the first inoculum was from a man and the second from a woman. The culture's haematopoietic activity was determined by the number of CFU-GM, total cell counts and the differential counts during four weeks. At the end of the study we recovered the cells from the supernatant of the culture and they were analyzed by in situ hybridization with an alpha centromeric probe specific to the X chromosome. RESULTS: In all cases we obtained a confluent stroma with production of haematopoiesis (cobblestone areas). The cells recovered at the end of the culture were, in all cases, from the second inoculum because they had a double signal with the X probe. The number of CFU-GM obtained was higher in bone marrow than in peripheral blood (34.5 and 9.2 respectively) however, the total cells were similar in both cases (2.3 x 10(5) and 2.9 x 10(5)) although the cellular subtypes varied depending on the second inoculum (B.M. or P.B.). CONCLUSION: Our data confirm that the dose of 15 Gy eradicate the haemopoiesis of first inoculum, which allowed to analyze stroma and progenitor cells, separately. In addition, the stroma is capable to support the hematopoiesis generated by progenitor cells from peripheral and bone marrow.