Autologous Marrow Mesenchymal Stem Cell Driving Bone Regeneration in a Rabbit Model of Femoral Head Osteonecrosis.

Osteonecrosis of the femoral head (ONFH) is a progressive degenerative disease that ultimately requires a total hip replacement. Mesenchymal stromal/stem cells (MSCs), particularly the ones isolated from bone marrow (BM), could be promising tools to restore bone tissue in ONFH. Here, we established a rabbit model to mimic the pathogenic features of human ONFH and to challenge an autologous MSC-based treatment.

Potency Biomarker Signature Genes from Multiparametric Osteogenesis Assays: Will cGMP Human Bone Marrow Mesenchymal Stromal Cells Make Bone?

In skeletal regeneration approaches using human bone marrow derived mesenchymal stromal cells (hBM-MSC), functional evaluation before implantation has traditionally used biomarkers identified using fetal bovine serum-based osteogenic induction media and time courses of at least two weeks. However, emerging pre-clinical evidence indicates donor-dependent discrepancies between these ex vivo measurements and the ability to form bone, calling for improved tests. Therefore, we adopted a multiparametric approach aiming to generate an osteogenic potency assay with improved correlation.

Mesenchymal progenitors expressing TRAIL induce apoptosis in sarcomas.

Sarcomas are frequent tumors in children and young adults that, despite a relative chemo-sensitivity, show high relapse rates with up to 80% of metastatic patients dying in 5 years from diagnosis. The real ontogeny of sarcomas is still debated and evidences suggest they may derive from precursors identified within mesenchymal stromal/stem cells (MSC) fractions. Recent studies on sarcoma microenvironment additionally indicated that MSC could take active part in generation of a supportive stroma.

Delayed marrow infusion in mice enhances hematopoietic and osteopoietic engraftment by facilitating transient expansion of the osteoblastic niche.

Transplantation of bone marrow cells leads to engraftment of osteopoietic and hematopoietic progenitors. We sought to determine whether the recently described transient expansion of the host osteoblastic niche after marrow radioablation promotes engraftment of both osteopoietic and hematopoietic progenitor cells. Mice infused with marrow cells 24 hours after total body irradiation (TBI) demonstrated significantly greater osteopoietic and hematopoietic progenitor chimerism than did mice infused at 30 minutes or 6 hours.

Transportation conditions for prompt use of ex vivo expanded and freshly harvested clinical-grade bone marrow mesenchymal stromal/stem cells for bone regeneration.

Successful preliminary studies have encouraged a more translational phase for stem cell research. Nevertheless, advances in the culture of human bone marrow-derived mesenchymal stromal/stem cells (hBM-MSC) and osteoconductive qualities of combined biomaterials can be undermined if necessary cell transportation procedures prove unviable. We aimed at evaluating the effect of transportation conditions on cell function, including the ability to form bone in vivo, using procedures suited to clinical application.

Transplanted murine long-term repopulating hematopoietic cells can differentiate to osteoblasts in the marrow stem cell niche.

Bone marrow transplantation (BMT) can give rise to donor-derived osteopoiesis in mice and humans; however, the source of this activity, whether a primitive osteoprogenitor or a transplantable marrow cell with dual hematopoietic and osteogenic potential, has eluded detection. To address this issue, we fractionated whole BM from mice according to cell surface immunophenotype and assayed the hematopoietic and osteopoietic potentials of the transplanted cells. Here, we show that a donor marrow cell capable of robust osteopoiesis possesses a surface phenotype of c-Kit(+) Lin(-) Sca-1(+) CD34(-/lo), identical to that of the long-term repopulating hematopoietic stem cell (LTR-HSC).

Mesenchymal stromal/stem cells markers in the human bone marrow.

Background Aims: Mesenchymal stromal/stem cells (MSCs) can be isolated from human bone marrow (BM), expanded ex vivo and identified via numerous surface antigens. Despite the importance of these cells in regenerative therapy programs, it is unclear whether the cell membrane signature defining MSC preparations ex vivo is determined during culture or may reflect an in vivo counterpart. BM-MSC phenotype in vivo requires further investigation.

Cytokine-induced osteopoietic differentiation of transplanted marrow cells.

Transplantation of whole bone marrow (BMT) leads to engraftment of both osteoprogenitor cells and hematopoietic cells; however, the robust osteopoietic chimerism seen early after BMT decreases with time. Using our established murine model, we demonstrate that a post-BMT regimen of either granulocyte-colony stimulating factor, growth hormone, parathyroid hormone, or stem cell factor each stimulates greater donor osteoblast chimerism at 4 months posttransplantation than saline-treated controls and approximates the robust osteopoietic chimerism seen early after BMT; however, only growth hormone led to significantly more donor-derived osteocytes than controls. Importantly, there were no adverse hematologic consequences of the different treatments.

Osteopoietic engraftment after bone marrow transplantation: effect of inbred strain of mice.

Objective: Transplantable osteoprogenitors, as well as hematopoietic progenitors, reside in bone marrow. We previously reported the first clinical trial of bone marrow transplantation (BMT) for a genetic disorder of bone, osteogenesis imperfecta. Although the patients demonstrated striking clinical benefits after transplantation, measured osteopoietic engraftment was low and did not seem to be durable.

Adipose-derived mesenchymal stem cells as stable source of tumor necrosis factor-related apoptosis-inducing ligand delivery for cancer therapy.

Adipose-derived mesenchymal stromal/stem cells (AD-MSC) may offer efficient tools for cell-based gene therapy approaches. In this study, we evaluated whether AD-MSC could deliver proapoptotic molecules for cancer treatment. Human AD-MSCs were isolated and transduced with a retroviral vector encoding full-length human tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), a proapoptotic ligand that induces apoptosis in a variety of human cancers but not normal tissues.

Restoration and reversible expansion of the osteoblastic hematopoietic stem cell niche after marrow radioablation.

Adequate recovery of hematopoietic stem cell (HSC) niches after cytotoxic conditioning regimens is essential to successful bone marrow transplantation. Yet, very little is known about the mechanisms that drive the restoration of these niches after bone marrow injury. Here we describe a profound disruption of the marrow microenvironment after lethal total body irradiation of mice that leads to the generation of osteoblasts restoring the HSC niche, followed by a transient, reversible expansion of this niche.

Donor cell-derived osteopoiesis originates from a self-renewing stem cell with a limited regenerative contribution after transplantation.

In principle, bone marrow transplantation should offer effective treatment for disorders originating from defects in mesenchymal stem cells. Results with the bone disease osteogenesis imperfecta support this hypothesis, although the rate of clinical improvement seen early after transplantation does not persist long term, raising questions as to the regenerative capacity of the donor-derived mesenchymal progenitors. We therefore studied the kinetics and histologic/anatomic pattern of osteopoietic engraftment after transplantation of GFP-expressing nonadherent marrow cells in mice.

"In vitro" and multicolor phenotypic characterization of cell subpopulations identified in fresh human adipose tissue stromal vascular fraction and in the derived mesenchymal stem cells.

Background: The stromal vascular fraction (SVF) is a heterogeneous cell population derived from the adipose tissue. There is still a lack of information concerning the characterization of the cell subpopulations constituting the SVF as well as its mesenchymal and haematopoietic potential. Furthermore there are great variations in its phenotypical characterization.

Post-transplant Kaposi sarcoma originates from the seeding of donor-derived progenitors.

Kaposi sarcoma (KS) is a vascular tumor that can develop in recipients of solid tissue transplants as a result of either primary infection or reactivation of a gammaherpesvirus, the KS- associated herpesvirus, also known as human herpesvirus-8 (HHV-8). We studied whether HHV-8 and the elusive KS progenitor cells could be transmitted from the donor through the grafts. We used a variety of molecular, cytogenetic, immunohistochemical and immunofluorescence methods to show that the HHV-8-infected neoplastic cells in post-transplant KS from five of eight renal transplant patients harbored either genetic or antigenic markers of their matched donors.

Severe pancytopenia and hemophagocytosis after HHV-8 primary infection in a renal transplant patient successfully treated with foscarnet.

We report the occurrence of human herpesvirus (HHV)-8 primary infection in an adult male kidney recipient. Four months after transplantation, the patient developed visceral Kaposi sarcoma, and 1 month later he presented with progressive and severe peripheral cytopenia, in the presence of a normocellular or hypercellular bone marrow (BM) with hemophagocytosis. HHV-8 was the sole pathogen detected by polymerase chain reaction either in the serum or in the BM.

HHV-8 infection in the transplantation setting: a concern only for solid organ transplant patients?

Early epidemiologic studies have shown an increased risk of Kaposi sarcoma (KS) in recipients of solid organ transplants, while KS is exceptional in the setting of autologous and allogeneic bone marrow (BM) and peripheral blood stem cell (PBSC) transplant patients. The recent discovery of human herpesvirus 8 (HHV-8) as the necessary etiologic agent of KS has stimulated studies to assess whether KS is the result of HHV-8 transmission from the donor or of reactivation of a pre-existing HHV-8 infection in the recipient host. An association of HHV-8 infection with lymphoid neoplasias has also been observed, identifying this herpesvirus as a possible causal agent of some Epstein-Barr virus negative post-transplant lymphoproliferative diseases.