Source Of Cells For Transplantation Research Articles

Mobilization and Collection of Peripheral Blood Stem Cells in Adults: Focus on Timing and Benchmarking.

Peripheral blood stem cells (PBSCs) are preferentially used as a hematopoietic stem cell source for autologous blood stem cell transplantation (ABSCT) upon high-dose chemotherapy (HDT) in a variety of hemato-oncologic diseases. As a prerequisite, hematopoietic stem cells have to be mobilized into the peripheral blood (PB) and collected by leukapheresis (LP). Despite continuous improvements, e.g., the introduction of plerixafor, current challenges are the further optimization regarding the leukapheresis procedure, preventing collection failures, as well as benchmarking and harmonization of mobilization approaches between institutions.This chapter summarizes the current PBSC mobilization and collection approaches and is focusing on timely orchestration of mobilization therapy, granulocyte colony-stimulating factor (G-CSF) application, and peripheral blood (PB) CD34+ cell assessment. Moreover, strategies for prediction and performance assessment of the PBSC collection yield are discussed.

The collagen scaffold supports hiPSC-derived NSC growth and restricts hiPSC.

The human induced pluripotent stem cells (hiPSC) are one of the promising candidates as patient specific cell source for autologous transplantation or modeling of diseases. The collagen (Col) scaffolds have been shown suitable to create in vitro biomimetic microenvironment for human neural stem cells, but their ability to accommodate stem cells at different stages of neural differentiation has not been verified yet. In this paper we compare lineage related hiPSC during neural differentiation for their ability to colonize Col scaffold. We have also focused on modification of collagen physicochemical properties with improved mechanical and thermal stability, without loss of its biological activity. The hiPSC expressing markers of pluripotency (OCT4, SOX2, NANOG) after neural commitment are NESTIN, GFAP, PDGFR alpha, beta- TUBULIN III, MAP-2, DCX, GalC positive. We have shown, that Col scaffold was not preferable for hiPSC culture, while the neurally committed population after seeding on Col scaffolds revealed good adhesion, viability, proliferation, along with sustaining markers of neuronal and glial differentiation. The Col scaffold-based 3D culture of hiPSC-NSCs may serve as a research tool for further translational studies.

Pancreatic Islet Transplantation in Humans: Recent Progress and Future Directions.

Pancreatic islet transplantation has become an established approach to β-cell replacement therapy for the treatment of insulin-deficient diabetes. Recent progress in techniques for islet isolation, islet culture, and peritransplant management of the islet transplant recipient has resulted in substantial improvements in metabolic and safety outcomes for patients. For patients requiring total or subtotal pancreatectomy for benign disease of the pancreas, isolation of islets from the diseased pancreas with intrahepatic transplantation of autologous islets can prevent or ameliorate postsurgical diabetes, and for patients previously experiencing painful recurrent acute or chronic pancreatitis, quality of life is substantially improved. For patients with type 1 diabetes or insulin-deficient forms of pancreatogenic (type 3c) diabetes, isolation of islets from a deceased donor pancreas with intrahepatic transplantation of allogeneic islets can ameliorate problematic hypoglycemia, stabilize glycemic lability, and maintain on-target glycemic control, consequently with improved quality of life, and often without the requirement for insulin therapy. Because the metabolic benefits are dependent on the numbers of islets transplanted that survive engraftment, recipients of autoislets are limited to receive the number of islets isolated from their own pancreas, whereas recipients of alloislets may receive islets isolated from more than one donor pancreas. The development of alternative sources of islet cells for transplantation, whether from autologous, allogeneic, or xenogeneic tissues, is an active area of investigation that promises to expand access and indications for islet transplantation in the future treatment of diabetes.

Autoimmune hemolytic anemia and immune thrombocytopenia following hematopoietic stem cell transplant: A critical review of the literature.

Autoimmune cytopenias (AIC) post-hematopoietic stem cell transplant (HSCT) are rare but exceptionally challenging complication. We conducted a comprehensive literature review and identified a pooled incidence of post-HSCT autoimmune hemolytic anemia and/or immune thrombocytopenia of 2.66% (SE=0.27) in pediatric patients. Nonmalignant disease, unrelated donor transplant, peripheral or cord blood stem cell source, conditioning regimen without total body irradiation, and presence of chronic graft-versus-host disease were prominent risk factors. Treatment was highly variable, and cytopenias were commonly refractory. AIC represent a significant post-HSCT complication. We report here the incidence, risk factors, and possible biology behind the development of AIC in pediatric post-HSCT patients.

Chronic Graft Versus Host Disease Burden and Relapse Rates Are Lower with Comparable Overall Survival and Graft Versus Host Disease Free, Relapse Free Survival Following Adult Umbilical Cord Blood Compared to Matched Sibling Peripheral Blood Stem Cell Transplantation

Abstract Background: Although matched related donors (MRD) are the preferred source of stem cells for allogeneic hematopoietic cell transplantation, umbilical cord blood (UCB) is a well-established donor source in patients without a MRD or matched unrelated donor (MUD). Prior studies (Eapen et al, Lancet Oncology 2010; Rocha et al, NEJM 2004) have shown similar overall survival and relapse rates after umbilical cord blood transplant (UCBT), and our group (Gutman et al, BMT 2016) has shown lower chronic graft-versus-host-disease (GVHD) when compared to MUD transplant. Based on these data, our preferred donor source is MRD followed by UCB. Here, we evaluate our data comparing transplant outcomes in UCBT recipients versus MRD recipients. Methods: We compared outcomes in all consecutive adult patients undergoing first MRD transplant versus first double UCBT from January 2010 to December 2017. Patient selection, graft-versus-host disease prophylaxis and transfusions were per institutional standards. Graft-versus-host-disease free, relapse free survival (GRFS) was defined by events that includedgrade 3-4 acute GVHD, moderate to severe chronic GVHD, relapse or any death. Results: Of the 296 patients studied, 187 underwent UCBT and 109 received MRD transplant. Graft failure occurred in 6 (3%) UCBT recipients (5 of whom received reduced intensity conditioning) and did not occur in any MRD transplant recipients. While the incidence of grade 2-4 acute GVHD was higher in UCBT recipients (p= 0.006), grade 3-4 acute GVHD was comparable (p= 0.36) between the two groups. Any chronic GVHD (p= 0.0000001) and moderate to severe chronic GVHD (p= 0.00011) was significantly higher in MRD transplant recipients (figure 1a and 1b). There were significantly lower disease relapses in UCBT recipients (n= 51, 27% versus n= 46, 42%; p= 0.0036) compared to MRD transplant recipients. Transplant related mortality was higher in UCBT recipients (n= 33, 42% versus n= 11, 23% in MRD transplant recipients; p= 0.03). There was no difference in GRFS (p=0.15, figure 1c) and overall survival (OS) in the 2 study cohorts (p=0.31, figure 1d). Conclusions: UCBT recipients as compared to MRD recipients had lower chronic GVHD and lower relapse rates with no difference in OS and the composite endpoint of GRFS. Based on these results, UCB remains an appropriate alternative donor source for hematopoietic cell transplantation and might result in improved quality of life by virtue of lower incidence of chronic GVHD in long-term transplant survivors. Disclosures Haverkos: Viracta Therapeutics: Membership on an entity's Board of Directors or advisory committees. Pollyea:Pfizer: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Agios: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Gilead: Consultancy; Celgene: Membership on an entity's Board of Directors or advisory committees; Argenx: Consultancy, Membership on an entity's Board of Directors or advisory committees; Curis: Membership on an entity's Board of Directors or advisory committees; Karyopharm: Membership on an entity's Board of Directors or advisory committees; Celyad: Consultancy, Membership on an entity's Board of Directors or advisory committees; AbbVie: Consultancy, Research Funding. Kamdar:Seattle Genetics: Membership on an entity's Board of Directors or advisory committees. Mark:Janssen, Takeda, Celgene, Amgen: Consultancy; BMS, Celgene: Research Funding; Celgene: Honoraria.

Is There Difference between the Survival Rate and Treatment Related Complications between Peripheral Blood Stem Cell Transplantation and Bone Marrow Transplantation for Pediatric Hematological Malignancy?: Systematic Review and Meta-Analysis

Background: As a source of cells for hematopoietic cell transplantation (HCT), peripheral blood stem cells (PBSC) have become a major alternative to bone marrow, the most common source of cells. A meta-analysis showed that the use of PBSC in adults is not superior with respect to overall survival, and the incidence of chronic graft-versus-host disease (GVHD) is more frequent after PBSC transplantation (PBSCT) than after bone marrow transplantation (BMT). Furthermore, several studies suggested that PBSCT in children results in poor overall survival compared with BMT, and the benefit of PBSCT is controversial. To elucidate this question, we conducted a systematic review and meta-analysis to compare the survival rate and treatment related complications of pediatric patients receiving PBSCT with those receiving BMT.Methods: Based on the pre-defined protocol, MEDLINE, EMBASE plus EMBASE classics, Cochrane Central Register of Controlled Trials, the International Clinical Trials Registry Platform Search Portal and Clinical Trials.gov records were searched from inception through July 25, 2018 with no language restriction. The search terms included “hematopoietic stem cell transplantation” AND “allogeneic transplantation” AND “children”. We included randomized control studies or cohort studies. The Newcastle-Ottawa Quality Assessment Scale was used to evaluate study quality. The primary outcome was to evaluate five-year overall survival after HCT. Secondary outcomes were five-year event-free survival after HCT, non-relapse mortality, the incidence of acute and chronic GVHD, and time to platelet and neutrophil engraftment. We performed meta-analyses using random effect models with risk ratios (RR) and a 95% confidence interval (CI). Heterogeneity was assessed using the I-squared statistic and chi-squared test. Publication bias was assessed with funnel plots.Results: We identified a total of 5,248 relevant studies. Seven cohort studies with a total of 4,328 patients (BMT group 3,185 patients and PBSCT group 1,143 patients) were included in the present study. There was no significant difference between PBSCT and BMT for five-year overall survival (RR: 1.17, 95% CI: 0.91-1.52, heterogeneity I2=69%, p=0.22) and five year event free survival (RR: 1.14, 95% CI: 0.93-1.39, heterogeneity I2=57%, p=0.05), respectively. The risk of chronic GVHD in the PBSCT group was higher than those in the BMT group (RR: 1.65, 95% CI: 1.18-2.03, heterogeneity I2=75%, p=0.002). The risk of non-relapse mortality with PBSCT was higher than with BMT (RR: 1.73, 95% CI: 1.50-1.99, heterogeneity I2=0%, p<0.00001), and the relapse rate did not show a significant difference between BMT and PBSCT (RR:1.26, 95% CI: 0.94-1.69, heterogeneity I2=71%, p=0.004).Conclusions: This meta-analysis did not show significant difference in overall survival or relapse between PBSCT and BMT for pediatric hematological malignancy. However, a higher risk of chronic GVHD and transplantation related mortality was associated with PBSCT. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Cord Blood Units Containing Lower CD34+ Cells (0.5 - 1.0 x 105 /kg) Could be Alternative Donor Candidates for Single-Unit Cord Blood Transplantation for Adults: A Retrospective Study of 421 Patients in a Single Institute

BACKGROUND: Cord blood is an established alternative donor cell source for allogeneic hematopoietic cell transplantation. However, engraftment failure is still a major concern after transplantation, especially for patients transplanted lower doses of donor cells. Higher CD34+ cell dose leads to a secure and fast engraftment, and the units of cord blood which contain CD34+ cells of 1.0 - 1.7 x 105 /kg at freezing or 1.0 - 1.2 x 105 /kg at thawing are recommended (Thomas' Hematopoietic Cell Transplantation, 5th Edition). Actually, most adult patients cannot obtain such sufficient cell dose-containing cord bloods and the feasibility of single-unit cord blood transplantation (CBT) containing lower CD34+ cell dose than 1.0 x 105 /kg is unclear.METHODS: To investigate the lower threshold of CD34+ cell dose, we studied the patients who received single-unit CBT as the first transplantation between 2009 and 2017. The patients whose ECOG performance status was 0 or 1, and who do not have donor-specific anti-HLA antibody (DSA) were analyzed. Institutional review board of Toranomon Hospital approved the study (research number #1666).RESULTS: A total of 421 patients were studied. The median age and body weight of patients was 57 years (range, 16 - 74) and 56.4 kg (32.2 - 94.6), respectively. Myeloid diseases accounted for 78% of the patients, and 83% were not in remission. Myeloablative conditioning regimens were used in 80% of the patients. All patients used Tac (26%) or Tac plus MMF (74%) as GVHD prevention. The median numbers of total nucleated cells and CD34+ cells were 2.61 x107 /kg (range, 1.57 - 5.85) and 0.86 x 105 /kg (0.29 - 3.77) at freezing, respectively. The cumulative incidence of neutrophil engraftment was 90.7% at 60 days after transplantation (95% confidence interval, 87.5 - 93.1). The median day of neutrophil engraftment was day 21 (range, 5 - 45). Multivariate analysis identified higher CD34+ cell dose, less HLA mismatch, and lymphoid disease as significant favorable factors for neutrophil engraftment (p < 0.05), and CD34+ cell dose was most significant among the following pre-transplant factors (HR 1.57, p < 0.00001): age (≤ 57 vs. >57 years), body weight (≤ 56.4 vs. > 56.4 kg), ECOG performance status (0 vs. 1), disease (myeloid vs. lymphoid), disease status (in CR vs. not in CR), anti-HLA antibody (not DSA) (positive vs. negative), total nucleated cell dose (≤ 2.61 vs. > 2.61 x 107 /kg), CD34+ cell dose (≤ 0.86 vs. >0.86 x 105 /kg), HLA antigen match (≤4/6 vs. ≥5/6), ABO match (match vs. mismatch), sex match (match vs. mismatch), GVHD prevention (Tac vs. TAC plus MMF), and the intensity of conditioning regimen (MAC vs. RIC). Then, we compared the cumulative incidence of neutrophil engraftment between 4 groups as follows: 90.2% for group A (> 1.5 x 105 /kg, n = 41); 91.7% for group B (1.0 - 1.5 x 105 /kg, n = 109); 91.4% for group C (0.5 - 1.0 x 105 /kg, n = 255); 75.0% for group D (< 0.5 x 105 /kg, n = 16) (p < 0.01). The median day of neutrophil engraftment was faster for the patients transplanted more CD34+ cell doses: day 17 for group A; day 19 for B; day 21 for C; day 26.5 for D (p < 0.0001). Next, we focused on group C transplanted lower CD34+ cell dose than the recommendation (0.5 - 1.0 x 105 /kg, n = 255).The patients were divided into 5 groups according to their CD34+ cell doses, and we compared their cumulative incidence of neutrophil engraftment as follows: 96.0% for group C1 (0.9 - 1.0 x 105 /kg, n = 50); 89.7% for group C2 (0.8 - 0.9 x 105 /kg, n = 39); 88.1% for group C3 (0.7 - 0.8 x 105 /kg, n = 67); 92.2% for group C4 (0.6 - 0.7 x 105 /kg, n = 51); 91.7% for group C5 (0.5 - 0.6 x 105 /kg, n = 48) (p = 0.03). The median day of neutrophil engraftment was significantly faster for the patients transplanted more CD34+ cell dose: day 20 for group C1; day 21 for C2; day 21 for C3; day 23 for C4; day 24 for C5 (p < 0.01). Overall survival was not significantly different between group A vs. B vs. C vs. D, nor group C1 vs. C2 vs. C3 vs. C4 vs. C5, respectively.DISCUSSION & CONCLUSION: Significantly faster neutrophil engraftment was demonstrated for patients transplanted more CD34+ cells after single-unit CBT. On the other hand, the cumulative incidences of neutrophil engraftment at day 60 were comparable among the patients who used > 0.5 x 105 /kg of CD34+ cells to be around 90%. The cord blood units containing 0.5 - 1.0 x 105 /kg at freezing could be alternative donor candidates for cord blood selection, if delayed engraftment was clinically acceptable for recipients. DisclosuresYamamoto:Bristol-Myers Squibb: Honoraria.

Structures of filum terminale and characteristics of ependymal cells of its central canal in rats

The filum terminale (FT) is a potential source of ependymal cells for transplantation. The present study was performed to clarify the characteristics of ependymal cells of the central canal (CC) of the FT in rats. The FT was a thin strand continuous with the conus medullaris (CM), a caudal end of the main spinal cord, situated at the L3-4 level in adult rats. The border between the CM and FT was not visible, but could be defined as the site where the strand was as thin as its more caudal segment. While the CM contained an appreciable amount of white and grey matter associated with the CC at its center, the FT had no or only a negligible amount of such spinal cord parenchymal tissue. The FT was tracked ca. 4 cm from the site defined above to the level of S4-5 in adult rats. The rostral part of the FT (FTI) included within the cauda equina is exposed to cerebrospinal fluid, whereas the more caudal part (FTE) was surrounded by a dense layer of connective tissue. Almost all ependymal cells were immunostained for Sox2, Sox9, FoxJ1, and CD133, generally recognized immunochemical markers for ependymal cells of the CC in the spinal cord. Ependymal cells of the CC of FT exhibited almost the same structural and immunohistochemical characteristics as those of the CC of the main spinal cord. Ependymal cells of FTI covered by a thin layer of connective tissue are considered appropriate for transplantation.

Peripheral Blood or Bone Marrow Stem Cells? Practical Considerations in Hematopoietic Stem Cell Transplantation.

Although peripheral blood stem cells (PBSC) have worldwide become the predominant source of progenitor cells for hematopoietic stem cell transplantation (HSCT), debate about their role compared with bone marrow (BM) has recently intensified, in large part based on the results of a multicenter Clinical Trials Network study which showed lower incidence of chronic graft-versus-host disease (cGVHD) and improved quality of life in recipients of myeloablative HLA-matched unrelated BM compared with PBSC transplants. However, in certain patient populations, PBSC may lead to improved clinical outcomes due to faster hematologic recovery, a lower risk of graft failure, and possibly a lower probability of relapse. This review will provide a comprehensive summary of studies comparing PBSC with BM as the graft source in terms of acute and chronic GVHD incidence, time to engraftment, and disease-free and overall survival probabilities after HLA-matched related and unrelated donor transplantation and haploidentical donor transplantation. Recommendations based on these studies regarding the use of PBSC versus BM for HSCT are offered.

Stemming retinal regeneration with pluripotent stem cells.

Cell replacement therapy is a promising treatment for irreversible retinal cell death in diverse diseases, such as age-related macular degeneration (AMD), Stargardt's disease, retinitis pigmentosa (RP) and glaucoma. These diseases are all characterized by the degeneration of one or two retinal cell types that cannot regenerate spontaneously in humans. Aberrant retinal pigment epithelial (RPE) cells can be observed through optical coherence tomography (OCT) in AMD patients. In RP patients, the morphological and functional abnormalities of RPE and photoreceptor layers are caused by a genetic abnormality. Stargardt's disease or juvenile macular degeneration, which is characterized by the loss of the RPE and photoreceptors in the macular area, causes central vision loss at an early age. Loss of retinal ganglion cells (RGCs) can be observed in patients with glaucoma. Once the retinal cell degeneration is triggered, no treatments can reverse it. Transplantation-based approaches have been proposed as a universal therapy to target patients with various concomitant diseases. Both the replacement of dead cells and neuroprotection are strategies used to rescue visual function in animal models of retinal degeneration. Diverse retinal cell types derived from pluripotent stem cells, including RPE cells, photoreceptors, RGCs and even retinal organoids with a layered structure, provide unlimited cell sources for transplantation. In addition, mesenchymal stem cells (MSCs) are multifunctional and protect degenerating retinal cells. The aim of this review is to summarize current findings from preclinical and clinical studies. We begin with a brief introduction to retinal degenerative diseases and cell death in diverse diseases, followed by methods for retinal cell generation. Preclinical and clinical studies are discussed, and future concerns about efficacy, safety and immunorejection are also addressed.

Role of Regulatory T Cells in Noninherited Maternal Antigen-Related Tolerance in Cord Blood: An in Vitro Study

Cord blood (CB) is an alternative stem cell source for allogeneic hematopoietic stem cell transplantation (HSCT). The unique advantages of using CB as a stem cell source are a degree of permissibility for HLA mismatch, rapid availability, and relatively risk-free cell collection. Because HLA is highly polymorphic and population-specific, optimal HLA-matched unrelated donors or cord blood units (CBUs) might not be available. In view of the possibility that matched CBUs that include noninherited maternal antigens (NIMAs) might contain acceptable HLA mismatches, we attempted to determine the degree of alloreactivity of CB mononuclear cells (MNCs) on stimulation by the maternal, paternal, and unrelated stimulator cells. Suppression of T cell proliferation, cytotoxicity, and a cytokine profile indicating suppressed Th1 and elevated IL-10 and TGF-β1 responses were observed in the mixed lymphocyte reaction in response to NIMAs. The increases in IL-10 and TGF-β1 production may be due to the Th2 response and/or regulatory T cells (Tregs). The reduced IL-10 and TGF-β1 production after CD25 depletion could have been due to removal of Tregs from the CB cells. Thus, Tregs appear to play an important role in the CB MNC response to NIMAs, possibly due to the induction of IL-10 and TGF-β1. We hope that our work can provide some evidence of the beneficial effect of NIMAs.

Peripheral blood stem cell mobilization; a look ahead.

Mobilized peripheral blood is the predominant source of stem and progenitor cells for hematologic transplantation. Successful transplant requires sufficient stem cells of high enough quality to recapitulate lifelong hematopoiesis, but in some patients and normal donors, reaching critical threshold stem cell numbers are difficult to achieve. Novel strategies, particularly those offering rapid mobilization and reduced costs, remains an area of interest.This review summarizes critical scientific underpinnings in understanding the process of stem cell mobilization, with a focus on new or improved strategies for their efficient collection and engraftment. Studies are described that provide new insights into the complexity of stem cell mobilization. Agents that target new pathways such HSC egress, identify strategies to collect more potent competing HSC and new methods to optimize stem cell collection and engraftment are being evaluated. Agents and more effective strategies that directly address the current shortcomings of hematopoietic stem cell mobilization and transplantation and offer the potential to facilitate collection and expand use of mobilized stem cells have been identified.

Apheresis on aged patients/donors with complicated backgrounds like ischemic heart disease, arrhythmia, and others

Peripheral blood stem cells (PBSCs) are currently one of the most important stem cell sources for hematopoietic stem cell transplantation as well as cell therapy for ischemic heart disease or critical limb ischemia. Thus, it is sometimes necessary to collect autologous PBSCs from donors who have comorbidities.In terms yield, a sufficient number of PBSCs can be collected from donors with comorbidities for performing cell therapy if their age is < 60 years or up to a maximum of 70 years, although the number of PBSCs collected from older donors would probably be lower than that obtained from younger donors. On the other hand, granulocyte colony-stimulating factor (G-CSF) administration sometimes results in severe adverse events (AEs), such as ischemic heart disease and vascular thrombosis. Therefore, it is very important to perform strict medical check-ups according to the standards for donor operations in each country before apheresis. The apheresis procedure and G-CSF administration should be performed after administering the appropriate treatment. There is very less information available regarding AEs related to citrate administration during apheresis in aged donors with complicated medical histories. Medical staff should have knowledge of the electrocardiogram (ECG) QTc prolongation that occurs during apheresis owing to hypocalcemia caused by citrate administration, necessitating electrocardiographic monitoring of patients. Calcium should be administered during apheresis to prevent citrate related symptoms.

Application of CRISPR/Cas9 technologies combined with iPSCs in the study and treatment of retinal degenerative diseases.

Retinal degeneration diseases, such as age-related macular degeneration and retinitis pigmentosa, affect millions of people worldwide and are major causes of irreversible blindness. Effective treatments for retinal degeneration, including drug therapy, gene augmentation or transplantation approaches, have been widely investigated. Nevertheless, more research should be dedicated to therapeutic methods to improve future clinical treatments. Recently, with the rapid development of genome-editing technology, gene therapy has become a potentially effective treatment for retinal degeneration diseases. A clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9) system has been developed as a powerful genome-editing tool in ophthalmic studies. The CRISPR/Cas9 system has been widely applied in basic research to develop animal models and gene therapies in vivo. With the ability to self-renew and the potential to differentiate into different types of cells, induced pluripotent stem cells (iPSCs) have already been used as a promising tool for understanding disease pathophysiology and evaluating the effect of drug and gene therapeutics. iPSCs are also a cell source for autologous transplantation. In this review, we compared genome-editing strategies and highlighted the advantages and concerns of the CRISPR/Cas9 system. Moreover, the latest progress and applications of the CRISPR/Cas9 system and its combination with iPSCs for the treatment of retinal degenerative diseases are summarized.

Immunological Properties of Human Embryonic Stem Cell-Derived Retinal Pigment Epithelial Cells.

SummaryAge-related macular degeneration is caused by dysfunction and loss of retinal pigment epithelium (RPE) cells, and their transplantation may rescue visual functions and delay disease progression. Human embryonic stem cells (hESCs) may be an unlimited source of RPE cells for allotransplantation. We analyzed the immunomodulatory properties of hESC-derived RPE (hESC-RPE) cells, and showed that they inhibited T cell responses. Co-culture experiments showed that RPE cells inhibited interfon-γ secretion and proliferation of activated T cells. Furthermore, hESC-RPE cells enhanced T cell apoptosis and secretion of the anti-inflammatory cytokine interleukin-10 (IL-10). In addition, RPE cells altered the expression of T cell activation markers, CD69 and CD25. RPE cells transplanted into RCS rats without immunosuppression survived, provided retinal rescue, and enhanced IL-10 blood levels. Our data suggest that hESC-RPE cells have immunosuppressive properties. Further studies will determine if these properties are sufficient to alleviate the need for immunosuppression therapy after their clinical allotransplantation.

Ectopic expression of factor VIII in MSCs and hepatocytes derived from rDNA targeted hESCs

Hemophilia A is an X-linked recessive bleeding disorder caused by FVIII gene deficiency, which may result in spontaneous joint hemorrhages or life-threatening bleeding. Currently, cell-based gene therapy via ex vivo transduction of transplantable cells with integrating gene-expressing vectors offers an attractive treatment for HA. In present study, we targeted an expression cassette of B-domain-deleted FVIII into the ribosomal DNA (rDNA) locus of human embryonic stem cells (hESCs) by transfection with a nonviral targeting plasmid pHrn. The targeted hESCs clone could be expanded and retained the main pluripotent properties of differentiation into three germ layers both in vitro and in vivo. Importantly, under defined induction conditions, the targeted hESCs could differentiated into functional mesenchymal stem cells (MSCs) and hepatocytes, as validated by relevant specific cell markers and functional examination. Tumorgenesis assay demonstrated that these cells are relatively safe for future applications. Analysis on gene expression revealed that exogenous FVIII mRNA and FVIII proteins were both present in differentiated MSCs and hepatocytes. These results indicated that through gene targeting at hESCs rDNA locus a persistent cell source of transplantable genetic-modified cells can be accomplished for HA therapy.

Application of amphiphilic fluorophore-derived nanoparticles to provide contrast to human embryonic stem cells without affecting their pluripotency and to monitor their differentiation into neuron-like cells

Fluorogenic labeling is a potential technique in biology that allows for direct detection and tracking of cells undergoing various biological processes. Compared to traditional genetic modification approaches, labeling cells with nanoparticles has advantages, especially for the additional safety they provide by avoiding genomic integration. However, it remains a challenge to determine whether nanoparticles interfere with cell traits and provide long-lasting signals in living cells. We employed an amphiphilic fluorophore-derived nanoparticle (denoted by TPE-11) bearing a tetraphenylethene (TPE) moiety and two ionic heads; this nanoparticle has an aggregation-induced emission (AIE) effect and the ability to self-assemble. TPE-11 exhibited the property of higher or longer fluorescence intensities in cell imaging than the other two nanomaterials under the same conditions. We used this nanomaterial to label human embryonic stem (hES) cells and monitor their differentiation. Treatment with low concentrations of TPE-11 (8.0 μg/mL) resulted in high-intensity labeling of hES cells, and immunostaining analysis and teratoma formation assays showed that at this concentration, their pluripotency remained unaltered. TPE-11 nanoparticles allowed for long-term monitoring of hES cell differentiation into neuron-like cells; remarkably, strong nanoparticle signals were detected throughout the nearly 40-day differentiation process. Thus, these results demonstrate that the TPE-11 nanoparticle has excellent biocompatibility for hES cells and is a potential fluorogen for labeling and tracking the differentiation of human pluripotent stem cells. Statement of SignificanceThis study uses a nanoparticle-based approach to label human embryonic stem (hES) cells and monitor their differentiation. hES cells are distinguished by two distinctive properties: the state of their pluripotency and the potential to differentiate into various cell types. Thus, these cells will be useful as a source of cells for transplantation or tissue engineering applications. We noticed the effect of aggregation-induced emission, and the ability to self-assemble could enhance the persistence of signals. Treatment with low concentrations of TPE-11 nanoparticles showed high-intensity labeling of hES cells, and immunostaining analysis and teratoma formation assays showed that at this concentration, their pluripotency remained unaltered. Additionally, these nanoparticles allowed for long-term monitoring of hES cell differentiation into neuron-like cells lasting for 40 days.

Defined Conditions for Differentiation of Functional Retinal Ganglion Cells From Human Pluripotent Stem Cells.

We aimed to establish an efficient method for retinal ganglion cell (RGC) differentiation from human pluripotent stem cells (hPSCs) using defined factors. To define the contribution of specific signal pathways to RGC development and optimize the differentiation of hPSCs toward RGCs, we examined RGC differentiation in three stages: (1) eye field progenitors expressing the eye field transcription factors (EFTFs), (2) RGC progenitors expressing MATH5, and (3) RGCs expressing BRN3B and ISLET1. By monitoring the condition that elicited the highest yield of cells expressing stage-specific markers, we determined the optimal concentrations and combinations of signaling pathways required for efficient generation of RGCs from hPSCs. Precise modulation of signaling pathways, including Wnt, insulin growth factor-1, and fibroblast growth factor, in combination with mechanical isolation of neural rosette cell clusters significantly enriched RX and PAX6 double-positive eye field progenitors from hPSCs by day 12. Furthermore, Notch signal inhibition facilitated differentiation into MATH5-positive progenitors at 90% efficiency by day 20, and these cells further differentiated to BRN3B and ISLET1 double-positive RGCs at 45% efficiency by day 40. RGCs differentiated via this method were functional as exemplified by their ability to generate action potentials, express microfilament components on neuronal processes, and exhibit axonal transportation of mitochondria. This protocol offers highly defined culture conditions for RGC differentiation from hPSCs and in vitro disease model and cell source for transplantation for diseases related to RGCs.

Benefits of Pre-harvest Peripheral Blood CD34 Counts Guided Single Dose Therapy with PLERIXAFOR in Autologous Hematopoietic Stem Cell Transplantation: A Retrospective Study at a Tertiary Care Institute in India.

Peripheral blood is a convenient source of stem cells for hematopoietic stem cell transplantation. However, in autologous transplants, the harvest failure rates are high because of inadequate mobilization using G-CSF alone. Plerixafor is a potent mobilizer when used with G-CSF. However, its routine use is limited by high cost. This is a retrospective study done at a tertiary care oncology centre in India. All the harvest records were analyzed between Jan 2015 and Nov 2017. May 2016 onwards pre-harvest peripheral blood CD34 count was done in all cases of autologous transplants on day 4 of G-CSF therapy and they were given a single dose of Plerixafor if counts were < 20 cell per cumm. The results were compared amongst various groups. A total of 321 cases were analyzed. 172/321 were allogenic transplant cases of which 5% (n = 7) failed to achieve a target live stem cell dose of > 2 million per kg of the recipient. The overall failure rate in autologous group (n = 149) was 27% (n = 41) (p ≤ 0.001 auto vs. allo). The failure rate was higher (36%, n = 28/77) when no intervention with Plerixafor was done. The overall failure rate in the group treated with pre-harvest 34 count based single dose therapy of Plerixafor was 18% (n = 13/72, p = 0.01). However, within this intervention group, the patients who had pre-harvest peripheral blood CD34 above the desired cutoff had a higher failure rate of 21% (p = 0.13). Pre-harvest CD34 count based intervention with Plerixafor help optimizing the cost.

Enhancing human cord blood hematopoietic stem cell engraftment by targeting nuclear hormone receptors.

Allogeneic hematopoietic cell transplantation (HCT) is a life-saving therapy for hematological and nonhematological diseases. Cord blood is a source of transplantable hematopoietic stem cells (HSCs), but limited numbers of HSCs in single cord blood units, which may cause delayed neutrophil, platelet, and immune cell reconstitution, is a major problem for efficient transplantation. Ex-vivo expansion and enhanced homing of cord blood HSC may overcome this disadvantage and improve its long-term engraftment. Here, we discuss the role of nuclear hormone receptors signaling in human cord blood HSC engraftment. Antagonizing retinoid acid receptor (RAR) signaling promotes human HSC expansion and increases myeloid cell production. Cord blood CD34 cells expanded by SR1 promotes efficient myeloid recovery after transplantation compared with control groups, and leads to successful engraftment. Short-term treatment of glucocorticoids enhances homing and long-term engraftment of human HSCs and HPCs in NSG mice. Peroxisome proliferator-activated receptor-γ (PPARγ) antagonism expands human HSCs and HPCs by preventing differentiation and enhancing glucose metabolism. These findings demonstrate that nuclear hormone receptor signaling components might be promising targets for improving human cord blood HCT. Better understanding of molecular mechanisms underlying human HSC expansion and homing mediated by nuclear hormone receptor signaling pathways will facilitate enhanced HCT efficacy.