The generation of hybrid electrospun nanofiber layer with extracellular matrix derived from human pluripotent stem cells, for regenerative medicine applications.

Extracellular matrix (ECM) has been utilized as a biological scaffold for tissue engineering applications in a variety of body systems, due to its bioactivity and biocompatibility. In the current study we developed a modified protocol for the efficient and reproducible derivation of mesenchymal progenitor cells (MPCs) from human embryonic stem cells as well as human induced pluripotent stem cells (hiPSCs) originating from hair follicle keratinocytes (HFKTs). ECM was produced from these MPCs and characterized in comparison to adipose mesenchymal stem cell ECM, demonstrating robust ECM generation by the excised HFKT-iPSC-MPCs.

Low dose BMP-2 treatment for bone repair using a PEGylated fibrinogen hydrogel matrix.

Bone repair strategies utilizing resorbable biomaterial implants aim to stimulate endogenous cells in order to gradually replace the implant with functional repair tissue. These biomaterials should therefore be biodegradable, osteoconductive, osteoinductive, and maintain their integrity until the newly formed host tissue can contribute proper function. In recent years there has been impressive clinical outcomes for this strategy when using osteoconductive hydrogel biomaterials in combination with osteoinductive growth factors such as human recombinant bone morphogenic protein (hrBMP-2).

Controlled release of BMP-2 from a sintered polymer scaffold enhances bone repair in a mouse calvarial defect model.

Sustained and controlled delivery of growth factors, such as bone morphogenetic protein 2 (BMP-2), from polymer scaffolds has excellent potential for enhancing bone regeneration. The present study investigated the use of novel sintered polymer scaffolds prepared using temperature-sensitive PLGA/PEG particles. Growth factors can be incorporated into these scaffolds by mixing the reconstituted growth factor with the particles prior to sintering.

The involvement of oxidants and NF-κB in cytokine-induced MMP-9 synthesis by bone marrow-derived osteoprogenitor cells.

Objective And Design: The activity of immune cells affects the balance between bone mineralization and resorption carried out by the opposing actions of osteoblasts and osteoclasts, respectively. This study was aimed at determining the possible interaction between inflammatory conditions and collagen type I degrading MMP (mainly MMP-2 and MMP-9) synthesis and secretion in rat osteoprogenitors.

Materials And Methods: The study was performed using primary rat bone marrow-derived osteoprogenitors during their advanced osteogenesis.

Lentiviral-mediated integrin α5 expression in human adult mesenchymal stromal cells promotes bone repair in mouse cranial and long-bone defects.

Abstract Adult human mesenchymal stromal cells (hMSCs) are an important source for tissue repair in regenerative medicine. Notably, targeted gene therapy in hMSCs to promote osteogenic differentiation may help in the development of novel therapeutic approaches for bone repair. We recently showed that α5 integrin (ITGA5) promotes osteoblast differentiation in bone marrow-derived hMSCs.

Engineering the growth factor microenvironment with fibronectin domains to promote wound and bone tissue healing.

Although growth factors naturally exert their morphogenetic influences within the context of the extracellular matrix microenvironment, the interactions among growth factors, their receptors, and other extracellular matrix components are typically ignored in clinical delivery of growth factors. We present an approach for engineering the cellular microenvironment to greatly accentuate the effects of vascular endothelial growth factor-A (VEGF-A) and platelet-derived growth factor-BB (PDGF-BB) for skin repair, and of bone morphogenetic protein-2 (BMP-2) and PDGF-BB for bone repair. A multifunctional recombinant fragment of fibronectin (FN) was engineered to comprise (i) a factor XIIIa substrate fibrin-binding sequence, (ii) the 9th to 10th type III FN repeat (FN III9-10) containing the major integrin-binding domain, and (iii) the 12th to 14th type III FN repeat (FN III12-14), which binds growth factors promiscuously, including VEGF-A165, PDGF-BB, and BMP-2.

A model for tissue engineering applications: femoral critical size defect in immunodeficient mice.

Animal models for preclinical functionality assays lie midway between in vitro systems such as cell culture and actual clinical trials. We have developed a novel external fixation device for femoral critical size defect (CSD) in the femurs of immunodeficient mice as an experimental model for studying bone regeneration and bone tissue engineering. The external fixation device comprises four pointed rods and dental acrylic paste.

Cell-scaffold transplant of hydrogel seeded with rat bone marrow progenitors for bone regeneration.

Bone is the second most frequently transplanted tissue in humans and efforts are focused on developing cell-scaffold constructs which can be employed for autologous implantation in place of allogenic transplants. The objective of the present study was to examine the efficacy of a gelatin-based hydrogel scaffold to support osteogenic differentiation of rat bone marrow-derived mesenchymal stem cells (MSCs) and its application in a cranial defect model. MSCs which were cultured on hydrogel under osteogenic conditions demonstrated typical osteogenic differentiation which included cluster formation with positive Alizarin Red S staining, sedimentation of calcium phosphate as defined by SEM and EDS spectroscopy and expression of mRNA osteogenic markers.

Slow-release human recombinant bone morphogenetic protein-2 embedded within electrospun scaffolds for regeneration of bone defect: in vitro and in vivo evaluation.

The design of mat-like scaffolds slow-releasing bone morphogenetic protein-2 (BMP-2) retaining bone regeneration functions has been a major challenge in tissue engineering. This study aimed to develop core-shell fiber scaffolds releasing BMP-2 to support bone regeneration. BMP-2 was incorporated in an aqueous core solution of poly(ethylene oxide), whereas the shell solution was made of polycaprolactone blended with poly(ethylene glycol).

Repair of full-thickness tendon injury using connective tissue progenitors efficiently derived from human embryonic stem cells and fetal tissues.

The use of stem cells for tissue engineering (TE) encourages scientists to design new platforms in the field of regenerative and reconstructive medicine. Human embryonic stem cells (hESC) have been proposed to be an important cell source for cell-based TE applications as well as an exciting tool for investigating the fundamentals of human development. Here, we describe the efficient derivation of connective tissue progenitors (CTPs) from hESC lines and fetal tissues.

Human bone marrow mesenchymal stem cells: a systematic reappraisal via the genostem experience.

Genostem (acronym for "Adult mesenchymal stem cells engineering for connective tissue disorders. From the bench to the bed side") has been an European consortium of 30 teams working together on human bone marrow Mesenchymal Stem Cell (MSC) biological properties and repair capacity. Part of Genostem activity has been dedicated to the study of basic issues on undifferentiated MSCs properties and on signalling pathways leading to the differentiation into 3 of the connective tissue lineages, osteoblastic, chondrocytic and tenocytic.

Priming integrin alpha5 promotes human mesenchymal stromal cell osteoblast differentiation and osteogenesis.

Adult human mesenchymal stromal cells (hMSCs) have the potential to differentiate into chondrogenic, adipogenic, or osteogenic lineages, providing a potential source for tissue regeneration. An important issue for efficient bone regeneration is to identify factors that can be targeted to promote the osteogenic potential of hMSCs. Using transcriptome analysis, we found that integrin alpha5 (ITGA5) expression is up-regulated during dexamethasone-induced osteoblast differentiation of hMSCs.

Isolation of progenitor cells from cord blood using adhesion matrices.

The aim of this study was to develop optimal conditions for selective adhesion and isolation of mesenchymal progenitor cells (MPCs) from cord blood and to determine their potential for osteogenic differentiation. Mononuclear cells (MNCs) were isolated by Ficoll-Paque gradient and plated onto 48-well culture plates precoated with: human or bovine collagen type I, human collagen type IV, fibronectin or matrigel. Cultures were incubated in alphaMEM containing fetal calf serum.

Isolation of progenitor cells from cord blood using adhesion matrices.

The aim of this study was to develop optimal conditions for selective adhesion and isolation of mesenchymal progenitor cells (PCs) from cord blood and to determine their potential for osteogenic differentiation. Mononuclear cells (MNCs) were isolated by Ficoll-Paque gradient and plated onto 48-well culture plates precoated with: human or bovine collagen type I, human collagen type IV, fibronectin or matrigel. Cultures were incubated in alphaMEM containing fetal calf serum.

3D scaffolds for bone marrow stem cell support in bone repair.

Bone tissue repair is one of the major concerns of regenerative medicine. The current need for tissue replacements has necessitated the development of a new science termed 'bone tissue engineering'. The basic organization of bone tissue requires the design and fabrication of a porous 3D structure or 'scaffold' to contain the bone-forming cells.

Analysis of progenitor cell-scaffold combinations by in vivo non-invasive photonic imaging.

Recent developments in stem cell research have promoted a flourishing of new biomaterials and scaffolds for tissue repair. However, there is a scarcity of procedures to monitor the performance of scaffold-stem cell combinations implanted in live animals, avoiding the inherent artefacts associated with in vitro assay conditions. We report the implementation of a procedure based on the use of the luciferase gene as a cell proliferation tracer to monitor, by in vivo non-invasive imaging, the performance of stem cell-biomaterial combinations used for tissue regeneration.

DT56a (Femarelle) stimulates bone formation in female rats.

Objective: DT56a is a natural compound for the treatment of menopausal symptoms and osteoporosis. The aim of this study was to examine the effects of long term treatment (two months) with DT56a on the skeletal tissues of intact and ovariectomised (OVX) adult rats.

Design: Thirty rats were divided into two groups, in one of which the rats were ovariectomised.

Mandibular defect repair by TGF-beta and IGF-1 released from a biodegradable osteoconductive hydrogel.

Purpose: Bone regeneration is crucial in the healing of defects in the craniofacial complex. The ability of transforming growth factor-beta1 (TGF-beta1) and insulin-like growth factor-1 (IGF-1), incorporated into a hydrogel scaffold to induce bone regeneration, was evaluated in a rat mandible defect model.

Material And Methods: Hydrogel scaffolds containing either transforming growth factor-beta1 (TGF-beta1), insulin-like growth factor-1 (IGF-1), TGF-beta+ IGF-1, or saline, were implanted in rat mandibular bone defects.

The effect of interleukin-8 on the viability of injected adipose tissue in nude mice.

Adipose tissue injection as a free graft for the correction of soft-tissue defects is a widespread procedure in plastic surgery. The main problem in achieving long-term soft-tissue augmentation is partial absorption of the injected fat and hence the need for overcorrection and re-injection. The purpose of this study was to improve the viability of the injected fat by the use of interleukin-8.

Activity of lung neutrophils and matrix metalloproteinases in cyclophosphamide-treated mice with experimental sepsis.

Sepsis in patients receiving chemotherapy may result in acute respiratory distress syndrome, despite decreased number of blood neutrophils [polymorphonuclear neutrophils (PMNs)]. In the present study, we investigated the correlation of cyclophosphamide (CY)-induced neutropenia with the destructive potential of lung PMN in respect to formation of septic acute lung injury (ALI). Mice were treated with 250 mg/kg of CY or saline (control) and subjected to cecal ligation and puncture (CLP) or sham operation.

The c-Jun dimerization protein 2 inhibits cell transformation and acts as a tumor suppressor gene.

The c-Jun dimerization protein, JDP2, is a member of the AP-1 (activating protein-1) family of the basic leucine zipper transcription factors. JDP2 can bind 12-O-tetradecanoylphorbol-13-acetate (TPA)-responsive element and cAMP-responsive element DNA response elements, resulting in the inhibition of transcription. Although the role of AP-1 in cell proliferation and malignant transformation is well established, the role of JDP2 in this process is of subject to debate.

Assessment of the ultrastructural and proliferative properties of human embryonic stem cell-derived cardiomyocytes.

Assessment of early ultrastructural development and cell-cycle regulation in human cardiac tissue is significantly hampered by the lack of a suitable in vitro model. Here we describe the possible utilization of human embryonic stem cell (ES) lines for investigation of these processes. With the use of the embryoid body (EB) differentiation system, human ES cell-derived cardiomyocytes at different developmental stages were isolated and their histomorphometric, ultrastructural, and proliferative properties were characterized.

Association of metalloproteinases, tissue inhibitors of matrix metalloproteinases, and proteoglycans with development, aging, and osteoarthritis processes in mouse temporomandibular joint.

The temporomandibular joint (TMJ) is an important growth and articulation center in the craniofacial complex. In aging it develops spontaneous degenerative osteoarthritic (OA) lesions. Metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPS) play key roles in extracellular matrix remodeling and degradation.

Expression of matrix metalloproteinases in articular cartilage of temporomandibular and knee joints of mice during growth, maturation, and aging.

Objective: This study examined the involvement of different matrix metalloproteinases (MMPs) in articular cartilage in the process of growth, maturation, and aging of mice, and compared the temporal changes in the expression of MMPs between temporomandibular joints (TMJ) and knee joints.

Methods: Homogenates of intact tibial plateau, femoral condyle, and TMJ condyle cartilages from animals of different ages were assessed for gelatinase (MMP-2 and MMP-9) activity by zymography. The messenger RNA (mRNA) expression of MMPs 1, 2, 3, 9, and 13 in tibial plateau cartilage was determined by semiquantitative reverse transcription-polymerase chain reaction, and immunohistochemistry was used to localize MMPs 2, 3, 9, and 13 in the knee joints and TMJ from mice of different ages.

CD10: a valuable tool for the light microscopic diagnosis of microvillous inclusion disease (familial microvillous atrophy).

Microvillous inclusion disease (MID) is a specific disorder of the intestinal brush border that leads to intractable secretory diarrhea in infants. At present, electron microscopic analysis is required for its definitive diagnosis. However, this technique is not always available or feasible, and the diagnostic microvillous inclusions may not be evident in all specimens.