Optimisation of mesenchymal stromal cells karyotyping analysis: implications for clinical use.

PURPOSE: The aim of this study was to optimise the yield of metaphases in mesenchymal stromal cells (MSC) in vitro cultures and to study the karyotype of MSC expanded in good manufacturing practice (GMP) conditions for clinical use. BACKGROUND: MSC are being increasingly used in clinical trials for a number of diseases. Biosafety demonstration in all cases is mandatory. Unfortunately, current standard karyotyping methods fail to obtain enough number of evaluable metaphases. METHODS AND MATERIALS: In the present work, to optimise the yield of metaphases in MSC expanded in vitro, we have tested several conditions by modifying colcemid concentration (we have tested 0.01, 0.05 and 0.1 µg mL(-1) ) and exposure time (during 5, 15 and 24 h). We further applied these optimised conditions to 61 MSC expansions in GMP conditions for clinical use. RESULTS: Our results show that the highest number of metaphases was obtained when MSC were incubated with 0.05 µg mL(-1) of colcemid overnight (15 h), compared to the remaining experimental conditions. In most cases (59/61 cases) enough number of metaphases was obtained. And what is more relevant, only in one case a karyotypic abnormality was found (trisomy of chromosome 10), and cells were subsequently discarded for clinical use. CONCLUSION: We describe here an optimal method to obtain enough number of metaphases for karyotype analysis of in vitro expanded MSCs, what is essential for their clinical use in cell therapy programmes.

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.

CD34 + cell dose and outcome of patients undergoing reduced-intensity-conditioning allogeneic peripheral blood stem cell transplantation.

While in bone marrow allogeneic transplantation the infusion of high doses of progenitor stem cells has a favourable impact on outcome, due to a faster hematopoietic and immune recovery, in the peripheral blood allo-setting the infusion of a high number of CD34 cells increases the risk of extensive chronic graft vs. host disease (cGVHD). This higher incidence of extensive cGVHD has an adverse impact on outcome due to a higher transplant related mortality, specially among patients receiving T-cell depleted allogeneic transplantation with myeloablative conditioning. By contrast, patients undergoing reduced intensity conditioning regimen may benefit from increasing higher CD34 + cell doses, especially those categorized as high risk according to disease status at transplant. Thus, the source of progenitors cells, type of conditioning and GVHD prophylaxis, among other factors, may influence the effect of the progenitor cell dose on outcome after allogeneic transplant.

Mesenchymal stem cells from multiple myeloma patients display distinct genomic profile as compared with those from normal donors.

It is an open question whether in multiple myeloma (MM) bone marrow stromal cells contain genomic alterations, which may contribute to the pathogenesis of the disease. We conducted an array-based comparative genomic hybridization (array-CGH) analysis to compare the extent of unbalanced genomic alterations in mesenchymal stem cells from 21 myeloma patients (MM-MSCs) and 12 normal donors (ND-MSCs) after in vitro culture expansion. Whereas ND-MSCs were devoid of genomic imbalances, several non-recurrent chromosomal gains and losses (>1 Mb size) were detected in MM-MSCs. Using real-time reverse transcription PCR, we found correlative deregulated expression for five genes encoded in regions for which genomic imbalances were detected using array-CGH. In addition, only MM-MSCs showed a specific pattern of 'hot-spot' regions with discrete (<1 Mb) genomic alterations, some of which were confirmed using fluorescence in situ hybridization (FISH). Within MM-MSC samples, unsupervised cluster analysis did not correlate with particular clinicobiological features of MM patients. We also explored whether cytogenetic abnormalities present in myelomatous plasma cells (PCs) were shared by matching MSCs from the same patients using FISH. All MM-MSCs were cytogenetically normal for the tested genomic alterations. Therefore we cannot support a common progenitor for myeloma PCs and MSCs.

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.

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.

Oral beclomethasone dipropionate for the treatment of gastrointestinal acute graft-versus-host disease (GVHD).

Acute graft-versus-host disease (aGVHD) remains one of the most severe complications after allogeneic transplantation; in particular, the presence of gut involvement has been related to increased mortality and poorer response. The use of systemic steroids remains the standard for first-line treatment despite its severe secondary effects. Beclomethasone dipropionate (BDP) is a topically active corticosteroid with low absorption, thereby avoiding many of the deleterious side effects associated with systemic steroids. In the present study we analyzed the efficacy of BDP in a series of 26 patients who were diagnosed with grade 1 and 2 gastrointestinal aGVHD. Twenty patients (77%) responded to BDP treatment, 17 (65.5%) reached complete remission (CR), and 3 (11.5%) showed partial response. Among those patients who reached CR, 5 relapsed, although 1 of them reached second CR after a second course of BDP; therefore, 13 (50%) of the 26 patients did not require systemic steroids to treat gastrointestinal aGVHD. CR rates in those showing gastrointestinal symptoms were 68% for patients with persistent nausea, 50% for those with vomiting, and 54% for those with diarrhea (P=.2). No patient included in the study developed any symptom related to adrenal axis suppression. Thirteen patients (50%) developed >or=1 infectious episode during the first 100 days after transplantation. Transplant-related mortality was 0% at 100 days, and overall transplant-related mortality was 30%, with only 2 patients dying due to infectious complications. Therefore, our study shows that monotherapy with oral BDP is an effective initial therapeutic approach for mild to moderate intestinal GVHD, which avoids complications related to systemic steroids.