Replacement of recipient stromal/mesenchymal cells after bone marrow transplantation using bone fragments and cultured osteoblast-like cells

Proteomic Comparison of Bone Marrow Derived Osteoblasts and Mesenchymal Stem Cells

Mesenchymal stem cells (MSCs) can differentiate into osteoblasts, and therapeutic targeting of these cells is considered both for malignant and non-malignant diseases. We analyzed global proteomic profiles for osteoblasts derived from ten and MSCs from six healthy individuals, and we quantified 5465 proteins for the osteoblasts and 5420 proteins for the MSCs. There was a large overlap in the profiles for the two cell types; 156 proteins were quantified only in osteoblasts and 111 proteins only for the MSCs. The osteoblast-specific proteins included several extracellular matrix proteins and a network including 27 proteins that influence intracellular signaling (Wnt/Notch/Bone morphogenic protein pathways) and bone mineralization. The osteoblasts and MSCs showed only minor age- and sex-dependent proteomic differences. Finally, the osteoblast and MSC proteomic profiles were altered by ex vivo culture in serum-free media. We conclude that although the proteomic profiles of osteoblasts and MSCs show many similarities, we identified several osteoblast-specific extracellular matrix proteins and an osteoblast-specific intracellular signaling network. Therapeutic targeting of these proteins will possibly have minor effects on MSCs. Furthermore, the use of ex vivo cultured osteoblasts/MSCs in clinical medicine will require careful standardization of the ex vivo handling of the cells.

Cytoprotective Preconditioning of Osteoblast-Like Cells with N-Acetyl-L-Cysteine for Bone Regeneration in Cell Therapy

Oxidative stress hinders tissue regeneration in cell therapy by inducing apoptosis and dysfunction in transplanted cells. N-acetyl-L-cysteine (NAC) reinforces cellular antioxidant capabilities by increasing a major cellular endogenous antioxidant molecule, glutathione, and promotes osteogenic differentiation. This study investigates the effects of pretreatment of osteoblast-like cells with NAC on oxidative stress-induced apoptosis and dysfunction and bone regeneration in local transplants. Rat femur bone marrow-derived osteoblast-like cells preincubated for 3 h with and without 5 mM NAC were cultured in a NAC-free osteogenic differentiation medium with continuous exposure to 50 μM hydrogen peroxide to induce oxidative stress. NAC preincubation prevented disruption of intracellular redox balance and alleviated apoptosis and negative impact on osteogenic differentiation, even under oxidative stress. Autologous osteoblast-like cells with and without NAC pretreatment in a collagen sponge vehicle were implanted in critical-size defects in rat femurs. In the third week, NAC-pretreated cells yielded complete defect closure with significantly matured lamellar bone tissue in contrast with poor bone healing by cells without pretreatment. Cell-tracking analysis demonstrated direct bone deposition by transplanted cells pretreated with NAC. Pretreatment of osteoblast-like cells with NAC enhances bone regeneration in local transplantation by preventing oxidative stress-induced apoptosis and dysfunction at the transplanted site.

Concise Review: Mesenchymal Stem Cell Therapy for Pediatric Disease: Perspectives on Success and Potential Improvements

Mesenchymal stem cells (MSCs) represent a potentially revolutionary therapy for a wide variety of pediatric diseases, but the optimal cell-based therapeutics for such diversity have not yet been specified. The published clinical trials for pediatric pulmonary, cardiac, orthopedic, endocrine, neurologic, and hematologic diseases provide evidence that MSCs are indeed efficacious, but the significant heterogeneity in therapeutic approaches between studies raises new questions. The purpose of this review is to stimulate new preclinical and clinical trials to investigate these factors. First, we discuss recent clinical trials for pediatric diseases studying MSCs obtained from bone marrow, umbilical cord and umbilical cord blood, placenta, amniotic fluid, and adipose tissue. We then identify factors, some unique to pediatrics, which must be examined to optimize therapeutic efficacy, including route of administration, dose, timing of administration, the role of ex vivo differentiation, cell culture techniques, donor factors, host factors, and the immunologic implications of allogeneic therapy. Finally, we discuss some of the practicalities of bringing cell-based therapy into the clinic, including regulatory and manufacturing considerations. The aim of this review is to inform future studies seeking to maximize therapeutic efficacy for each disease and for each patient. Stem Cells Translational Medicine 2017;6:539-565.

Mesenchymal stem cell transplantation in multiple sclerosis

Mesenchymal stem cells (MSCs) are pluripotent non-hematopoietic precursor cells that can be isolated from bone marrow and numerous other tissues, culture-expanded to purity, and induced to differentiate in vitro and in vivo into mesodermal derivatives. MSCs exhibit many phenotypic and functional similarities to pericytes. The immunomodulatory, tissue protective, and repair-promoting properties of MSCs demonstrated both in vitro and in animal models make them an attractive potential therapy for MS and other conditions characterized by inflammation and/or tissue injury. Other potential advantages of MSCs as a therapeutic include the relative ease of culture expansion, relative immunoprivilege allowing allogeneic transplantation, and their ability to traffic from blood to areas of tissue allowing intravascular administration. The overall published experience with MSC transplantation in MS is modest, but several small case series and preliminary studies yielded promising results. Several groups, including us, recently initiated formal studies of autologous, culture-expanded, bone marrow-derived MSC transplantation in MS. Although there are several potential safety concerns, to date, the procedure has been well tolerated. Future studies that more definitively assess efficacy also will need to address several technical issues.

Mesenchymal stem cell therapy in diabetes mellitus: progress and challenges

Advanced type 2 diabetes mellitus is associated with significant morbidity and mortality due to cardiovascular, nervous, and renal complications. Attempts to cure diabetes mellitus using islet transplantation have been successful in providing a source for insulin secreting cells. However, limited donors, graft rejection, the need for continued immune suppression, and exhaustion of the donor cell pool prompted the search for a more sustained source of insulin secreting cells. Stem cell therapy is a promising alternative for islet transplantation in type 2 diabetic patients who fail to control hyperglycemia even with insulin injection. Autologous stem cell transplantation may provide the best outcome for those patients, since autologous cells are readily available and do not entail prolonged hospital stays or sustained immunotoxic therapy. Among autologous adult stem cells, mesenchymal stem cells (MSCs) therapy has been applied with varying degrees of success in both animal models and in clinical trials. This review will focus on the advantages of MSCs over other types of stem cells and the possible mechanisms by which MSCs transplant restores normoglycemia in type 2 diabetic patients. Sources of MSCs including autologous cells from diabetic patients and the use of various differentiation protocols in relation to best transplant outcome will be discussed.

The potential of mesenchymal stromal cells as a novel cellular therapy for multiple sclerosis

Multiple sclerosis (MS) is an inflammatory neurodegenerative disease of the CNS for which only partially effective therapies exist. Intense research defining the underlying immune pathophysiology is advancing both the understanding of MS as well as revealing potential targets for disease intervention. Mesenchymal stromal cell (MSC) therapy has the potential to modulate aberrant immune responses causing demyelination and axonal injury associated with MS, as well as to repair and restore damaged CNS tissue and cells. This article reviews the pathophysiology underlying MS, as well as providing a cutting-edge perspective into the field of MSC therapy based upon the experience of authors intrinsically involved in MS and MSC basic and translational science research.

Cell therapy in bone healing disorders

In addition to osteosynthetic stabilizing techniques and autologous bone transplantations, so-called orthobiologics play an increasing role in the treatment of bone healing disorders. Besides the use of various growth factors, more and more new data suggest that cell-based therapies promote local bone regeneration. For ethical and biological reasons, clinical application of progenitor cells on the musculoskeletal system is limited to autologous, postpartum stem cells. Intraoperative one-step treatment with autologous progenitor cells, in particular, delivered promising results in preliminary clinical studies. This article provides an overview of the rationale for, and characteristics of the clinical application of cell-based therapy to treat osseous defects based on a review of existing literature and our own experience with more than 100 patients. Most clinical trials report successful bone regeneration after the application of mixed cell populations from bone marrow. The autologous application of human bone marrow cells which are not expanded ex vivo has medico-legal advantages. However, there is a lack of prospective randomized studies including controls for cell therapy for bone defects. Autologous bone marrow cell therapy seems to be a promising treatment option which may reduce the amount of bone grafting in future.

Mesenchymal stem cells at the intersection of cell and gene therapy

IMPORTANCE OF THE FIELD

Mesenchymal stem cells have the ability to differentiate into osteoblasts, chondrocytes and adipocytes. Along with differentiation, MSCs can modulate inflammation, home to damaged tissues and secrete bioactive molecules. These properties can be enhanced through genetic-modification that would combine the best of both cell and gene therapy fields to treat monogenic and multigenic diseases.

AREAS COVERED IN THIS REVIEW

Findings demonstrating the immunomodulation, homing and paracrine activities of MSCs followed by a summary of the current research utilizing MSCs as a vector for gene therapy, focusing on skeletal disorders, but also cardiovascular disease, ischemic damage and cancer.

WHAT THE READER WILL GAIN

MSCs are a possible therapy for many diseases, especially those related to the musculoskeletal system, as a standalone treatment, or in combination with factors that enhance the abilities of these cells to migrate, survive or promote healing through anti-inflammatory and immunomodulatory effects, differentiation, angiogenesis or delivery of cytolytic or anabolic agents.

TAKE HOME MESSAGE

Genetically-modified MSCs are a promising area of research that would be improved by focusing on the biology of MSCs that could lead to identification of the natural and engrafting MSC-niche and a consensus on how to isolate and expand MSCs for therapeutic purposes.

Acute hepatic failure-derived bone marrow mesenchymal stem cells express hepatic progenitor cell genes

Hepatic progenitor cell (HPC) transplantation is a promising alternative to liver transplantation for patients with end-stage liver disease. However, the precise origin of HPCs is unclear. This study aimed to determine whether bone marrow mesenchymal stem cells (BMSCs) isolated from rats in acute hepatic failure (AHF) possess hepatic potential and/or characteristics. BMSCs were isolated from normal rats as well as rats in which AHF was induced by D-galactosamine. HPCs and primary hepatocytes were isolated from normal rats for comparison. The Affymetrix GeneChip Rat Genome 230 2.0 Array was used to perform transcriptome profiling of the AHF-derived BMSCs and HPCs. The results showed that AHF-derived BMSCs had a gene expression profile significantly different from that of control BMSCs. More than 87.7% of the genes/probe sets that were upregulated more than 2-fold in AHF-derived BMSCs were expressed by HPCs, including 12 genes involved in liver development, early hepatocyte differentiation and hepatocyte metabolism. Confirmatory quantitative RT-PCR analysis yielded similar results. In addition, 940 probe sets/genes were expressed in both AHF-derived BMSCs and HPCs but were absent in control cells. Compared to the control cells, AHF-derived BMSCs shared more commonly expressed genes with HPCs. AHF-derived BMSCs have a hepatic transcriptional profile and express many of the same genes expressed by HPCs, strongly suggesting that BMSCs may be a resource for hepatocyte regeneration, and further confirming their potential as a strong source of hepatocyte regeneration during severe hepatic damage.

Transcriptional profiling and hepatogenic potential of acute hepatic failure-derived bone marrow mesenchymal stem cells

Liver stem cell (LSC) transplantation is a promising alternate approach to liver transplantation for patients with end-stage liver disease. However, the precise origin of LSCs remains unclear. Herein we determine if bone marrow mesenchymal stem cells (BMSCs) isolated from rats in acute hepatic failure (AHF) possess hepatic characteristics and have differentiation potential. BMSCs were isolated from AHF and sham-operated rats, and primary hepatocytes were isolated from normal rats for comparison. The transcriptomic profile of BMSCs and primary hepatocytes was analyzed using the Affymetrix GeneChip Rat Genome 230 2.0 Array. BMSCs isolated from AHF and normal rats were induced to differentiate into hepatocytes in vitro and the degree of hepatic differentiation was assessed using quantitative real time RT-PCR, immunohistochemistry, and biochemical assays. AHF-derived BMSCs had a significantly different gene expression profile compared to control BMSCs. Thirty-four gene/probe sets were expressed in both AHF-derived BMSCs and primary hepatocytes, but were absent in control-derived BMSCs, including 3 hepatocyte-specific genes. Forty-four genes were up-regulated more than 2-fold in AHF-derived BMSCs compared to controls, including 3 genes involved in hepatocyte metabolism and development. Furthermore, AHF-derived BMSCs expressed more hepatocyte related genes than control BMSCs. Additional experiments to validate the differentiation of AHF-derived BMSCs, compared to control-derived BMSCs, showed that several hepatocyte-specific genes and proteins [such as albumin (ALB) and alpha fetoprotein (AFP)] were expressed earlier, and at higher levels, after 1 week of differentiation. Hepatocyte-specific metabolic functions were also significantly higher in the AHF group compared to control cells.

CONCLUSION

AHF-derived BMSCs had a hepatic transcriptional profile and expressed hepatocyte specific genes early during differentiation, and possessed greater hepatogenic potency in vitro compared to cells isolated from control animals, further confirming their potential as a stem cell-based therapy for end-stage liver disease.

Effects of epigallocatechin gallate on osteogenic capability of human mesenchymal stem cells after suspension in phosphate-buffered saline

Administration of culture-expanded mesenchymal stem cells (MSCs) has been sought for regeneration of various damaged tissues/organs in clinical situations. Liquid suspensions of MSCs have either been directly injected into organs or generally infused. In this study, we focused on the viability and differentiation of MSCs after suspension in phosphate-buffered saline. When the MSCs were treated with epigallocatechin gallate, which is purified from green tea catechin, the MSCs showed high viability as well as osteogenic differentiation capability even while suspended in phosphate-buffered saline for 4 days at 4 degrees C. In contrast, nontreated MSCs showed low viability and showed hardly any differentiation. The rate of proliferation of the treated MSCs was much higher than that of the nontreated MSCs. These results indicate the usefulness of epigallocatechin gallate treatment for fabrication of ready-to-use cellular products of MSC suspension.

Bone marrow-derived mesenchymal stem cells

Human mesenchymal stem cells (MSCs) contribute to the regeneration of mesenchymal tissues, and are essential in providing support for the growth and differentiation of primitive hemopoietic cells within the bone marrow microenvironment. Techniques are now available to isolate human MSCs and manipulate their expansion in vitro under defined culture conditions without change of phenotype or loss of function. Mesenchymal stem cells have generated a great deal of interest in many clinical settings, including that of regenerative medicine, immune modulation and tissue engineering. Studies have already demonstrated the feasibility of transplanted MSCs providing crucial new cellular therapy. In this review, many aspects of the MSC will be discussed, with the main focus being on clinical studies that describe the potential of MSCs to treat patients with hematological malignancies who are undergoing chemotherapy and/or radiotherapy.

New bone formation by allogeneic mesenchymal stem cell transplantation in a patient with perinatal hypophosphatasia

Mesenchymal stem cells (MSCs) can show osteogenic differentiation capability when implanted in vivo, as well as cultured in vitro; therefore we attempted to use allogeneic MSCs for an 8-month-old patient with hypophosphatasia. MSCs were obtained by culture expansion of fresh marrow from the patient's father. Some of the MSCs were further cultured under osteogenic conditions on a culture dish or porous hydroxyapatite ceramics, resulting in cultured osteoblasts and osteogenic constructs, respectively. The MSCs and osteoblasts were injected into the patient, and the constructs were implanted locally. After traditional bone marrow transplantation, the MSCs, osteoblasts, and osteogenic constructs were used for treatment and to improve the patient's respiratory condition and skeletal abnormality. The condition worsened again, and an MSC booster shot was administered. At the same time, the construct was retrieved. The respiratory condition improved, and the retrieved construct showed de novo bone derived from both donor and patient cells. We demonstrated the importance of allogeneic MSC transplantation for hypophosphatasia and the constructs as an alternative to bone fragments that provided further osteogenic capability in the patient.

Autoimmune disease: is it a disorder of the microenvironment?

Systemic lupus erythematosus (SLE) is a common systemic autoimmune disease that involves several vital organs including the cardiovascular system, joints, and kidneys. The pathology is characterized by accumulation of autoreactive lymphocytes that attack the patients' own tissues, secretion of autoantibodies and deposition of immune complexes in vital organs. Chronic widespread inflammation is the hallmark of SLE and the target of current therapy. According to recent theories, intonating immune circuits of inflammatory cytokines and immune cells constitute highly specialized targets for SLE therapy, which nonetheless consists for the most part of anti-inflammatory medications and cytotoxic drugs. For advanced autoimmune disorders, cell therapy aiming at introducing "healthy" stem cells has been promising, keeping in mind that in its current state, stem cell therapy is reserved for the most advanced diseases refractory to traditional therapy. Ongoing studies in our laboratories examined the role of the bone marrow microenvironment, in particular, mesenchymal stem cells (MSCs) in the etiopathogenesis of SLE. Specifically, we are testing the hypothesis that, in human SLE mouse model, marrow MSCs are defective structurally and functionally. Preliminary data indicate that structural and functional defects in MSC population from an autoimmune mouse model for human SLE may contribute to this pathology and consequently present a target for cell therapy.

Transplantable marrow osteoprogenitors engraft in discrete saturable sites in the marrow microenvironment

OBJECTIVE

Based on the recognition that marrow contains progenitors for bone as well as blood, we undertook the first trial of bone marrow transplantation (BMT) for a genetic disorder of bone, osteogenesis imperfecta. While we documented striking clinical benefit soon after transplantation, the measured level of osteopoietic engraftment was low. To improve the efficacy of BMT for bone disorders, we sought to gain insight into the cellular mechanism of engraftment of transplantable marrow osteoprogenitors.

MATERIALS AND METHODS

We transplanted unfractionated bone marrow harvested from green fluorescent protein-transgenic FVB/N mice into lethally irradiated FVB/N recipients. At 3 weeks posttransplantation, we assessed hematopoietic engraftment by flow cytometry and osteopoietic engraftment by immunohistochemical staining for the green fluorescent protein.

RESULTS

We show that engraftment of transplantable marrow osteoprogenitors is saturable with a maximal engraftment of about 15% of all bone cells in the epiphysis and metaphysis of the femur at 3 weeks after transplantation. The number of engrafting sites is not up- or downregulated in response to initial progenitor cell engraftment, and there is no evidence for clonal succession of osteopoietic differentiation of engrafted progenitors.

CONCLUSIONS

Our findings indicate that the capacity for initial osteopoietic engraftment after BMT is limited and "megadose" stem cell transplantation is unlikely to enhance engraftment. Thus, novel strategies to foster osteopoietic chimerism must be developed.

Facilitation of hematopoietic recovery by bone grafts with intra-bone marrow-bone marrow transplantation

We have previously shown that T cells can acquire donor-type major histocompatibility complex (MHC) restriction and can interact with both donor-type antigen-presenting cells (APCs) and B cells, when adult donor bones are co-grafted with intravenous (IV) injection of bone marrow cells (BMCs) in order to supply donor bone marrow (BM) stromal cells. We have also found that the direct injection of donor BMCs into recipient BM (intra-bone marrow-bone marrow transplantation: IBM-BMT) produces more rapid reconstitution (including T-cell functions) and higher survival rates than IV injection (IV-BMT) even in chimerism-resistant combinations. In the present study, we show that the co-administration of bones from suckling (2-3 days old) donor mice is also effective in the IBM-BMT system. Even when a relatively low number of BMCs were injected into adult (more than 15 weeks old) mice, complete reconstitution was achieved in the mice that had received IBM-BMT+bone grafts, but not in the mice that had received IBM-BMT alone. Most BM and splenic adherent cells obtained from the recipients that had received IBM-BMT+bone grafts were reconstituted by donor-type cells. Both T-cell proliferation and plaque-forming cell assays indicated that the T cells of such mice showed donor-type MHC restriction. Moreover, the analyses of thymic sections using confocal microscopy revealed that donor BM stromal cells had migrated into the thymus. Thus, the co-administration of donor bones has great advantages for allogeneic BMT in adult mice.

Immunomodulation by mesenchymal stem cells and clinical experience

Mesenchymal stem cells (MSCs) from adult marrow can differentiate in vitro and in vivo into various cell types, such as bone, fat and cartilage. MSCs preferentially home to damaged tissue and may have therapeutic potential. In vitro data suggest that MSCs have low inherent immunogenicity as they induce little, if any, proliferation of allogeneic lymphocytes. Instead, MSCs appear to be immunosuppressive in vitro. They inhibit T-cell proliferation to alloantigens and mitogens and prevent the development of cytotoxic T-cells. In vivo, MSCs prolong skin allograft survival and have several immunomodulatory effects, which are presented and discussed in the present study. Possible clinical applications include therapy-resistant severe acute graft-versus-host disease, tissue repair, treatment of rejection of organ allografts and autoimmune disorders.

Infantile hypophosphatasia: transplantation therapy trial using bone fragments and cultured osteoblasts

BACKGROUND

Hypophosphatasia (HPP) is a rare, heritable, metabolic bone disease due to deficient activity of the tissue-nonspecific isoenzyme of alkaline phosphatase. The infantile form features severe rickets often causing death in the first year of life from respiratory complications. There is no established medical treatment. In 1997, an 8-month-old girl with worsening and life-threatening infantile HPP improved considerably after marrow cell transplantation.

OBJECTIVE

Our aim was to better understand and to advance these encouraging transplantation results.

DESIGN

In 1999, based on emerging mouse transplantation models involving implanted donor bone fragments as well as osteoblast-like cells cultured from bone, we treated a 9-month-old girl suffering a similar course of infantile HPP.

RESULTS

Four months later, radiographs demonstrated improved skeletal mineralization. Twenty months later, PCR analysis of adherent cells cultured from recipient bone suggested the presence of small amounts of paternal (donor) DNA despite the absence of hematopoietic engraftment. This patient, now 8 yr old (7 yr after transplantation), is active and growing, and has the clinical phenotype of the more mild, childhood form of HPP.

CONCLUSIONS

Cumulative experience suggests that, after immune tolerance, donor bone fragments and marrow may provide precursor cells for distribution and engraftment in the skeletal microenvironment in HPP patients to form tissue-nonspecific isoenzyme of alkaline phosphatase-replete osteoblasts that can improve mineralization.

Mesenchymal stem cells in stem cell transplant recipients are damaged and remain of host origin

The aim of this study was to investigate the expansion capacity and origin of bone marrow-derived mesenchymal stem cells (MSCs) in 34 patients who received a sex-mismatched stem cell transplant (SCT). Polymerase chain reaction (PCR) analysis of the amelogenin gene (AMEL) was used to detect donor-derived MSCs. Cultured MSCs were hybridized with fluorescence in situ hybridization (FISH) probes for chromosomes X and Y to distinguish cells of donor origin from those of host origin. The MSCs of 31 of the 34 patients showed confluent stroma, and the MSCs from 24 of these 31 patients were successfully passaged more than 5 times and were able to be used for PCR and FISH analyses. The colony-forming unit-fibroblast, confluence time, and passage numbers of the MSCs and the colony-forming capacity of the hematopoietic progenitor cells of the patients were significantly different from those of 30 healthy control subjects. Flow cytometry results showed that the proportion of CD14(+)CD45(+) cells, which are regarded as monocytes/macrophages, in cultured MSCs (fifth passage) was less than 0.04%. PCR and FISH analyses revealed that the MSC-derived cells in all 24 patients were from the host. In conclusion, the expansion capacity of MSCs in patients who receive an SCT is damaged, and the MSCs originate from the host.