Cell therapy for prenatal repair of myelomeningocele: A systematic review.

Myelomeningocele (MMC) is a spinal cord congenital defect that leads to paraplegia, bladder incontinence and bowel dysfunction. A randomized human trial demonstrated that in utero surgical repair of the MMC defect improves lower limb motor function. However, functional recovery remains incomplete. Stem cell therapy has recently generated great interest in the field of prenatal repair of MMC. In this systematic review we attempt to provide an overview of the current application of stem cells in different animal models of MMC. Publications were retrieved from PubMed and Cochrane Library databases. This process yielded twenty-two studies for inclusion in this review, experimenting five different types of stem cells: human embryonic stem cells, neural stem cells, induced pluripotent stem cells, human amniotic fluid stem cells, and mesenchymal stem cells (MSCs). Rodents and ovine were the two major species used for animal model studies. The source, the aims, and the main results were analyzed. Stem cell therapy appears to be a promising candidate for prenatal repair of MMC, especially MSCs. Further explorations in ovine and rodent models, reporting clinical and functional results, are necessary before an application in humans.

Pro-angiogenic effect of RANTES-loaded polysaccharide-based microparticles for a mouse ischemia therapy.

Peripheral arterial disease results from the chronic obstruction of arteries leading to critical hindlimb ischemia. The aim was to develop a new therapeutic strategy of revascularization by using biodegradable and biocompatible polysaccharides-based microparticles (MP) to treat the mouse hindlimb ischemia. For this purpose, we deliver the pro-angiogenic chemokine Regulated upon Activation, Normal T-cell Expressed and Secreted (RANTES)/CCL5 in the mouse ischemic hindlimb, in solution or incorporated into polysaccharide-based microparticles. We demonstrate that RANTES-loaded microparticles improve the clinical score, induce the revascularization and the muscle regeneration in injured mice limb. To decipher the mechanisms underlying RANTES effects in vivo, we demonstrate that RANTES increases the spreading, the migration of human endothelial progenitor cells (EPC) and the formation of vascular network. The main receptors of RANTES i.e. CCR5, syndecan-4 and CD44 expressed at endothelial progenitor cell surface are involved in RANTES-induced in vitro biological effects on EPC. By using two RANTES mutants, [E66A]-RANTES with impaired ability to oligomerize, and [44AANA47]-RANTES mutated in the main RANTES-glycosaminoglycan binding site, we demonstrate that both chemokine oligomerization and binding site to glycosaminoglycans are essential for RANTES-induced angiogenesis in vitro. Herein we improved the muscle regeneration and revascularization after RANTES-loaded MP local injection in mice hindlimb ischemia.

18F-FDG labelling of hematopoietic stem cells: Dynamic study of bone marrow homing by PET-CT imaging and impact on cell functionality.

PURPOSE OF THE STUDY: After transplantation, cord blood (CB) hematopoietic stem and progenitor cells (HSPCs) are able to home to the bone marrow niche and to reconstitute the hematopoietic system. PET-CT imaging may be a useful method to monitor this parameter in different conditions. The aim of our study was to set up an efficient method for HSPC radiolabelling with [18F] fluorodeoxyglucose (18F-FDG) and to follow early HSPC homing through PET-CT in mice. MATERIALS AND METHODS: Purified CB HSPCs were radiolabelled with 18F-FDG at 37° C with various conditions of cell concentration, incubation time and radioactivity concentration in order to define the in vitro condition that allows both sufficient 18F-FDG uptake to get high quality PET imaging, and preservation of HSPC viability and functional properties during 3h after radiolabelling. Then, 24h after 2.25Gy irradiation, eight NOD-scid/γc-/- mice were injected with 18F-FDG-labelled HSPCs, the biodistribution of which was followed using micro-PET-CT. RESULTS: The optimal incubation time was 45min with a stability of 48.3%±12.8% after 180min. The radio-uptake rate we obtained was 7.2%±1.7% with an activity of 5.6±2.1 MBq. Three hours after radiolabelling, viability was 96.7%±3.4%. Fifteen hours after radiolabelling, cell viability was 64.0%±2.3%, migration ability diminished from 51.0%±23.6% to 12.0%±9.1%, clonogenic capacity was null, and long-term engraftment in NSG mice also decreased compared to unlabelled cells. Micro-PET-CT experiments showed an accumulation of radiolabelled HSPCs for 2.5h after injection in the bone marrow and a slight elution of 18F-FDG. CONCLUSION: The activity of the obtained 18F-FDG-labelled HSPCs was sufficient to perform the micro-PET-CT imaging. Although the radiolabelling had a significant toxicity on HSPCs 15h after labelling, this technique allowed monitoring the beginning of HSPC homing into the bone marrow.

Esophageal tissue engineering: Current status and perspectives.

Tissue engineering, which consists of the combination and in vivo implantation of elements required for tissue remodeling toward a specific organ phenotype, could be an alternative for classical techniques of esophageal replacement. The current hybrid approach entails creation of an esophageal substitute composed of an acellular matrix and autologous epithelial and muscle cells provides the most successful results. Current research is based on the use of mesenchymal stem cells, whose potential for differentiation and proangioogenic, immune-modulator and anti-inflammatory properties are important assets. In the near future, esophageal substitutes could be constructed from acellular "intelligent matrices" that contain the molecules necessary for tissue regeneration; this should allow circumvention of the implantation step and still obtain standardized in vivo biological responses. At present, tissue engineering applications to esophageal replacement are limited to enlargement plasties with absorbable, non-cellular matrices. Nevertheless, the application of existing clinical techniques for replacement of other organs by tissue engineering in combination with a multiplication of translational research protocols for esophageal replacement in large animals should soon pave the way for health agencies to authorize clinical trials.

Equivalent outcomes using reduced intensity or conventional myeloablative conditioning transplantation for patients aged 35 years and over with AML.

Allogeneic hematopoietic stem cell transplantation provides the best chance of long-term survival for patients with AML, but is associated with an unpredictable risk of treatment-related mortality. From January 2000 to December 2010, we compared the outcomes for patients with AML aged 35 and over using reduced-intensity conditioning (RIC, N=60) or conventional myeloablative conditioning (MAC) regimen (N=72) transplantation. The median follow-up was 47 months (10-134). The 4-year cumulative incidence of non-relapse mortality was 21%. After adjusting for cytogenetic risk, gender donor/recipient mismatch and CD34+ cells, non-relapse mortality was significantly lower with the RIC regimen (P=0.027). The 4-year cumulative incidence of relapse was 38% and no difference was observed in the adjusted relapse rate between the two groups. The 4-year OS rate was 46%. Using both Cox regression and inverse probability-of-treatment weighted (IPTW) method, a similar OS rate was found with both regimens (adjusted hazard ratios for conventional vs reduced of 1.14 (95% CI 0.67-1.93, P=0.64) with Cox regression, and 1.14 (95% CI 0.55-2.34, P=0.73) with IPTW). Until prospective trials are completed, this study supports the use of a reduced-intensity regimen prior to transplantation for patients with AML aged 35 and over.

Quality controls on cord blood unit contiguous segments: recommendation of the SFGM-TC.

In the attempt to harmonize clinical practices between different French transplantation centers, the French Society of Bone Marrow Transplantation and Cell Therapies (SFGM-TC) set up its fourth annual series of workshops which brought together practitioners from all of its member centers. These workshops took place in September 2013 in Lille. Literature and intra-laboratories studies suggest that attached segment is representative of cord blood unit (CBU). Nevertheless, some discrepancies have been observed when analyzing large data registries. To address these issues, we have listed recommendations to increase the standardization of segment processing and quality control (QC), information on units of measurement and specifications and action to be taken in case of out of specifications QC results on segment.

Matched unrelated or matched sibling donors result in comparable outcomes after non-myeloablative HSCT in patients with AML or MDS.

The impact of allelic HLA matching in patients with AML and myelodysplastic syndrome (MDS) who receive allogeneic PBSC after a reduced-intensity conditioning (RIC) regimen is unclear. From January 2000 to December 2010, 108 consecutive patients with AML (n=63) and MDS (n=45) received PBSC after RIC in our center, either from siblings (n=70) or from matched unrelated donors (MUD; 10/10 high resolution, n=38). Conditioning regimen was fludarabine based in 95% of patients and GvHD prophylaxis was mostly cyclosporine plus mycophenolate. Patient characteristics were similar between sibling and MUD for age (median 57 years), gender and disease distribution. Conditioning regimen (more anti-thymocyte globulin (ATG) in MUD), donor age (younger for MUD) and number of CD34+ cells infused (higher in MUD) were different. The median follow-up was 36 months (range 2-72). Engraftment, GvHD, TRM, relapse rate and OS at 3 years were comparable between sibling and MUD. After adjustment for age, cytogenetic risk, ATG and number of CD34+ cells infused, donor type still did not influence OS. In patients with AML or MDS, HSCT from MUD using PBSC after a RIC regimen led to similar outcomes than from Siblings.

Primary hematopoietic cells from DBA patients with mutations in RPL11 and RPS19 genes exhibit distinct erythroid phenotype in vitro.

Diamond-Blackfan anemia (DBA) is caused by aberrant ribosomal biogenesis due to ribosomal protein (RP) gene mutations. To develop mechanistic understanding of DBA pathogenesis, we studied CD34⁺ cells from peripheral blood of DBA patients carrying RPL11 and RPS19 ribosomal gene mutations and determined their ability to undergo erythroid differentiation in vitro. RPS19 mutations induced a decrease in proliferation of progenitor cells, but the terminal erythroid differentiation was normal with little or no apoptosis. This phenotype was related to a G0/G1 cell cycle arrest associated with activation of the p53 pathway. In marked contrast, RPL11 mutations led to a dramatic decrease in progenitor cell proliferation and a delayed erythroid differentiation with a marked increase in apoptosis and G0/G1 cell cycle arrest with activation of p53. Infection of cord blood CD34⁺ cells with specific short hairpin (sh) RNAs against RPS19 or RPL11 recapitulated the two distinct phenotypes in concordance with findings from primary cells. In both cases, the phenotype has been reverted by shRNA p53 knockdown. These results show that p53 pathway activation has an important role in pathogenesis of DBA and can be independent of the RPL11 pathway. These findings shed new insights into the pathogenesis of DBA.

Cord blood-circulating endothelial progenitors for treatment of vascular diseases.

Adult peripheral blood (PB) endothelial progenitor cells (EPC) are produced in the bone marrow and are able to integrate vascular structures in sites of neoangiogenesis. EPCs thus represent a potential therapeutic tool for ischaemic diseases. However, use of autologous EPCs in cell therapy is limited by their rarity in adult PB. Cord blood (CB) contains more EPCs than PB, and they are functional after expansion. They form primary colonies that give rise to secondary colonies, each yielding more than 10(7) cells after few passages. The number of endothelial cells obtained from one unit of CB is compatible with potential clinical application. EPC colonies can be securely produced, expanded and cryopreserved in close culture devices and endothelial cells produced in these conditions are functional as shown in different in vitro and in vivo assays. As CB EPC-derived endothelial cells would be allogeneic to patients, it would be of interest to prepare them from ready-existing CB banks. We show that not all frozen CB units from a CB bank are able to generate EPC colonies in culture, and when they do so, number of colonies is lower than that obtained with fresh CB units. However, endothelial cells derived from frozen CB have the same phenotypical and functional properties than those derived from fresh CB. This indicates that CB cryopreservation should be improved to preserve integrity of stem cells other than haematopoietic ones. Feasibility of using CB for clinical applications will be validated in porcine models of ischaemia.

Outcomes, infections, and immune reconstitution after double cord blood transplantation in patients with high-risk hematological diseases.

Double unrelated cord blood transplant (dUCBT) has been used to circumvent cell dose limitation of single UCBT; however, few data are available describing outcomes, infectious disease, and immune recovery. We analyzed 35 consecutive dUCBT recipients with high-risk malignant disorders (n=21) and bone marrow failure syndromes (n=14). Median follow-up was 32 months. Conditioning regimen was myeloablative in 14 and reduced intensity in 21 patients. Median infused nucleated cell dose was 4 × 10(7) /kg. Median time to absolute neutrophil count >0.5 × 10(9) /L was 25 days. Cumulative incidence (CI) of acute grade II-IV graft-versus-host disease was 47%. Estimated overall survival at 2 years was 48%. CI of first viral infections at 1 year was 92%. We observed 49 viral infections in 30 patients, 34 bacterial infections in 19 patients, and 16 fungal or parasitic infections in 12 patients. Lymphocyte subset analyses were performed at 3, 6, 9, and >12 months after dUCBT. Decreased T-cell and B-cell counts with expansion of natural killer cells were observed until 9 months post transplantation. Recovery of thymopoiesis measured by T-cell receptor excision circles was impaired until 9 months after dUCBT, when the appearance of new thymic precursors was observed. Delayed immune recovery and high incidence of infectious complications were observed after dUCBT in patients with high-risk hematological diseases.

Mesenchymal stem cells: Stem cell therapy perspectives for type 1 diabetes.

Mesenchymal stem cells (MSCs) are multipotent non-haematopoietic progenitor cells that are being explored as a promising new treatment for tissue regeneration. Although their immunomodulatory properties are not yet completely understood, their low immunogenic potential together with their effects on immune response make them a promising therapeutic tool for severe refractory autoimmune diseases. Type 1 diabetes is characterized by T cell-mediated autoimmune destruction of pancreatic beta cells. While insulin replacement represents the current therapy for type 1 diabetes, its metabolic control remains difficult, as exogenous insulin cannot exactly mimic the physiology of insulin secretion. Pancreatic or islet transplantation can provide exogenous insulin independence, but is limited by its intrinsic complications and the scarcity of organ donors. In this context, stem cell therapy, based on the generation of insulin-producing cells (IPCs) derived from MSCs, represents an attractive possibility. In this review, we provide a brief characterization of MSC immunomodulatory effects, and present the current experimental evidence for the potential therapeutic efficacy of MSC transplantation in diabetes.

[Mesenchymal stem cells and immunomodulation: toward new immunosuppressive strategies for the treatment of autoimmune diseases?]. / Cellules souches mésenchymateuses et immunomodulation : vers de nouvelles stratégies immunosuppressives pour le traitement des maladies auto-immunes ?

Mesenchymal stem cells (MSC) represent a population of the bone marrow microenvironment, which participates in the regulation of haematopoietic stem cells (HSC) self-renewal and differentiation. MSC are multipotent non-haematopoietic progenitors, which have been explored as a promising treatment in tissue regeneration. Both in vitro and in vivo, the MSC inhibit the T, B, NK and dendritic cell functions. Although MSC immunomodulating properties are not yet completely understood, their low immunogenic potential can be used as a therapeutic tool not only for regenerative medicine, but also for the treatment of graft-versus-host disease (GVHD) after bone marrow transplantation as well as for specific cases of severe refractory autoimmune diseases. Experimental and clinical data gave encouraging results, showing that MSC injection allowed controlling refractory GVHD, restoring bone development in children with osteogenesis imperfecta or improving heart function after myocardial infarction. Phase I-II studies are in progress in various countries to investigate the potential benefit from MSC due to their immunosuppressive properties, as an adjunctive therapy for severe refractory autoimmune disease.

Association of drug metabolism gene polymorphisms with toxicities, graft-versus-host disease and survival after HLA-identical sibling hematopoietic stem cell transplantation for patients with leukemia.

Individual differences in drug efficacy or toxicity can be influenced by genetic factors. We investigated whether polymorphisms of pharmacogenes that interfere with metabolism of drugs used in conditioning regimen and graft-versus-host disease (GvHD) prophylaxis could be associated with outcomes after HLA-identical hematopoietic stem cell transplantation (HSCT). Pharmacogenes and their polymorphisms were studied in 107 donors and patients with leukemia receiving HSCT. Candidate genes were: P450 cytochrome family (CYP2B6), glutathione-S-transferase family (GST), multidrug-resistance gene, methylenetetrahydrofolate reductase (MTHFR) and vitamin D receptor (VDR). The end points studied were oral mucositis (OM), hemorrhagic cystitis (HC), toxicity and venoocclusive disease of the liver (VOD), GvHD, transplantation-related mortality (TRM) and survival. Multivariate analyses, using death as a competing event, were performed adjusting for clinical factors. Among other clinical and genetic factors, polymorphisms of CYP2B6 genes that interfere with cyclophosphamide metabolism were associated with OM (recipient CYP2B6(*)4; P=0.0067), HC (recipient CYP2B6(*)2; P=0.03) and VOD (donor CYP2B6(*)6; P=0.03). Recipient MTHFR polymorphisms (C677T) were associated with acute GvHD (P=0.03), and recipient VDR TaqI with TRM and overall survival (P=0.006 and P=0.04, respectively).Genetic factors that interfere with drug metabolisms are associated with treatment-related toxicities, GvHD and survival after HLA-identical HSCT in patients with leukemia and should be investigated prospectively.

Double cord blood transplantation in patients with high risk bone marrow failure syndromes.

Patients with bone marrow failure syndromes (BMFS) who reject a first allogeneic transplant or fail immunosuppressive therapy (IST) have an especially grim prognosis. We report 14 patients (eight adults, six children) transplanted with double cord blood transplantation (dUCBT) for BMFS. Neutrophil recovery was observed in eight patients, with full donor chimerism of one unit, and acute GVHD in 10. With a median follow-up of 23 months, the estimated 2 years overall survival was 80 +/- 17% and 33 +/- 16% for patients with acquired and inherited BMFS, respectively. Transplantation of two partially HLA-matched UCB thus enables salvage treatment of high-risk patients with BMFS.

Phenotypical and functional characteristics of in vitro expanded bone marrow mesenchymal stem cells from patients with systemic sclerosis.

BACKGROUND: Mesenchymal stem cells (MSCs) have a potential immunomodulatory role in autoimmune disease; however, the qualitative properties and haematopoietic support capacity of MSCs derived from patients with autoimmune disease is unclear. OBJECTIVES: To further characterise phenotypically and functionally bone marrow (BM)-derived MSCs from patients with systemic sclerosis (SSc). METHODS: Key parameters of BM-derived MSC function and phenotype were assessed in 12 patients with SSc and compared with 13 healthy normal controls. The parameters included the ability to: form colony-forming unit fibroblasts (CFU-F), differentiate along the adipogenic and osteogenic lineages, express cell surface antigens defining the MSCs population, support normal haematopoiesis and suppress in vitro lymphocyte proliferation induced by either anti-CD3epsilon plus anti-CD28 monoclonal antibodies or the mixed lymphocyte reaction. RESULTS: SSc MSCs were shown to have a similar characteristic phenotype, capacities to form CFU-F and to differentiate along adipogenic and osteogenic lineages as those of healthy donor MSCs. The ability of SSc MSCs to support long-term haematopoiesis was also identical to that of controls. Both healthy donor and SSc BM MSCs reduced the proliferation of autologous and allogeneic peripheral blood mononuclear cells in a cell number dependent fashion. CONCLUSIONS: These results show that BM-derived MSCs from patients with SSc under the described culture conditions exhibit the same phenotypic, proliferative, differentiation potential and immunosuppressive properties as their healthy counterparts and could therefore be considered in an autologous setting. Further studies are needed to ensure the quality and safety of large-scale expansion of patient MSCs prior to their potential use in clinical trials.

Long-term follow-up results after autologous haematopoietic stem cell transplantation for severe systemic sclerosis.

OBJECTIVE: Systemic sclerosis (SSc) is a generalised autoimmune disease, causing morbidity and a reduced life expectancy, especially in patients with rapidly progressive diffuse cutaneous SSc. As no proven treatment exists, autologous haematopoietic stem cell transplantation (HSCT) is employed as a new therapeutic strategy in patients with a poor prognosis. This study reports the effects on survival, skin and major organ function of HSCT in patients with severe diffuse cutaneous SSc. PATIENTS AND METHODS: A total of 26 patients were evaluated. Peripheral blood stem cells were collected using cyclophosphamide (4 g/m2) and rHu G-CSF (5 to 10 microg/kg/day) and were reinfused after positive CD34+ selection. For conditioning, cyclophosphamide 200 mg/kg was used. RESULTS: After a median follow-up of 5.3 (1-7.5) years, 81% (n = 21/26) of the patients demonstrated a clinically beneficial response. The Kaplan-Meier estimated survival at 5 years was 96.2% (95% CI 89-100%) and at 7 years 84.8% (95% CI 70.2-100%) and event-free survival, defined as survival without mortality, relapse or progression of SSc, resulting in major organ dysfunction was 64.3% (95% CI 47.9-86%) at 5 years and 57.1% (95% CI 39.3-83%) at 7 years. CONCLUSION: This study confirms that autologous HSCT in selected patients with severe diffuse cutaneous SSc results in sustained improvement of skin thickening and stabilisation of organ function up to 7 years after transplantation.

Microbial contamination of BM products before and after processing: a report of incidence and immediate adverse events in 257 grafts.

BACKGROUND: The incidence and potential clinical consequences of bacterial contamination of autologous and allogeneic BM products remains open to question. We report our experience of bacterial contamination of BM grafts and adverse events that occurred after transplantation. METHODS: From January 2003 to February 2006, 257 BM harvests were processed and infused at our institution. Analysis of microbial contamination incidence before and after processing, sensitivity spectra of isolated bacteria and adverse events after graft infusion were analyzed. RESULTS: Nineteen of 257 BM (7.4%) were contaminated. Coagulase-negative Staphylococcus (n=9) and Propionibacterium acnes (n=6) were the most frequently isolated microorganisms. Two of nine coagulase-negative staphylococci were found to be resistant to erythromycin and two of six P. acnes to fosfomycin and gentamycin. The frequency and severity of immediate adverse events reported in patients receiving a contaminated graft were similar to those observed in patients receiving a non-contaminated product. No major adverse sequelae occurred after infusion of contaminated grafts. Finally, none of the patients transplanted with a contaminated graft developed bacteriemia that could have been related to the isolated microorganism. DISCUSSION: Microbial contamination of BM progenitor cell grafts does not induce severe clinical complications or infectious diseases after infusion. The vast majority of isolated pathogens were skin contaminants.