Sevil Köse

Boron Containing Nano Hydroxyapatites (B-n-HAp) Stimulate Mesenchymal Stem Cell Adhesion, Proliferation and Differentiation

Osteoporosis (OP) is a systemic metabolic disease identified with decrease of bone mineral density and deterioration of microstructure leading to fragility fractures in elderly. Boron (B) is assumed to stimulate osteoblasts. Hydroxyapatite (HAp) is clinically used to conduct bone regeneration and improves implant integration. Nano(n)-HAp expands the surface area for cell adhesion and may improve bone regeneration and tissue integration. The objective of this study was to examine the adhesion, proliferation and differentiation of B-n-HAp with mesenchymal stem cells (MSC’s). Human bone marrow derived MSC’s phenotype was assessed using scanning and transmission electron microscopy after combining with B-n-HAp and n-HAp. Cell adhesion and proliferation potential of these ceramics was examined with the real time cell analysis (xCELLigence, Roche Applied Science and ACEA Bioscience, USA) system and adipogenic-osteogenic differentiation was analyzed with morphological and quantitative methods. MSC’s adhesion and proliferation rates (cell index, 4.50) were higher than controls (cell index, 4.00). Adipogenic and osteogenic differentiation potential of MSC’s remained unchanged in the presence of B-n-HAp ceramics. In conclusion, B-n-HAp stimulates MSC’s adhesion, proliferation and differentiation and has a potential to regenerate bone tissue.

Biomaterial and Stem Cell Interactions: Histological Biocompatibility.

Advancements in biomaterials and stem cell technology have lead current medical technology to tissue engineering and regenerative medicine. Human engineered cartilage, bone, fascia, tendon, nerve and skin tissues have been used for the treatment of tissue injuries and degenerative diseases in combination with embryonic, fetal or adult stem and progenitor cells. Mesenchymal stem cells are one of the most extensively studied adult stem cell population and are widely utilized in cell therapies. Regeneration and 3-dimensional reconstruction of specialized connective tissues by combining differently originated micro and nanoscaled, natural or synthetic scaffolds with stem or progenitor cells are highly expected to guarantee patients to maintain acceptable life quality. In this review we discuss the important issues in biomaterial and stem cell interactions based on histological biocompatibility, updating recent basic research in this field and addressing possible future perspectives.

Mesenchymal Stem Cells and Nano-Bioceramics for Bone Regeneration.

Orthopedic disorders and trauma usually result in bone loss. Bone grafts are widely used to replace this tissue. Bone grafts excluding autografts unfortunately have disadvantages like evoking immune response, contamination and rejection. Autografts are of limited sources and optimum biomaterials that can replace bone have been searched for several decades. Bioceramics, which have the similar inorganic structure of natural bone, are widely used to regenerate bone or coat metallic implants. As people continuously look for a higher life quality, there are developments in technology almost everyday to meet their expectations. Nanotechnology is one of such technologies and it attracts everyones attention in biomaterial science. Nano scale biomaterials have many advantages like larger surface area and higher biocompatibility and these properties make them more preferable than micro scale. Also, stem cells are used for bone regeneration besides nano-bioceramics due to their differentiation characteristics. This review covers current research on nano-bioceramics and mesenchymal stem cells and their role in bone regeneration.

Human bone marrow mesenchymal stem cells secrete endocannabinoids that stimulate in vitro hematopoietic stem cell migration effectively comparable to beta-adrenergic stimulation

Granulocyte colony-stimulating factor (G-CSF) is a well-known hematopoietic stem cell (HSC)-mobilizing agent used in both allogeneic and autologous transplantation. However, a proportion of patients or healthy donors fail to mobilize a sufficient number of cells. New mobilization agents are therefore needed. Endocannabinoids (eCBs) are endogenous lipid mediators generated in the brain and peripheral tissues and activate the cannabinoid receptors CB1 and CB2. We suggest that eCBs may act as mobilizers of HSCs from the bone marrow (BM) under stress conditions as beta-adrenergic receptors (Adrβ). This study demonstrates that BM mesenchymal stem cells (MSCs) secrete anandamide (AEA) and 2-arachidonylglycerol (2-AG) and the peripheral blood (PB) and BM microenvironment contain AEA and 2-AG. 2-AG levels are significantly higher in PB of the G-CSF-treated group compared with BM plasma. BM mononuclear cells (MNCs) and CD34+ HSCs express CB1, CB2, and Adrβ subtypes. CD34+ HSCs had higher CB1 and CB2 receptor expression in G-CSF-untreated and G-CSF-treated groups compared with MSCs. MNCs but not MSCs expressed CB1 and CB2 receptors based on qRT-PCR and flow cytometry. AEA- and 2-AG-stimulated HSC migration was blocked by eCB receptor antagonists in an in vitro migration assay. In conclusion, components of the eCB system and their interaction with Adrβ subtypes were demonstrated on HSCs and MSCs of G-CSF-treated and G-CSF-untreated healthy donors in vitro, revealing that eCBs might be potential candidates to enhance or facilitate G-CSF-mediated HSC migration under stress conditions in a clinical setting.

Lactobacillus rhamnosus could inhibit Porphyromonas gingivalis derived CXCL8 attenuation

ABSTRACT An increasing body of evidence suggests that the use of probiotic bacteria is a promising intervention approach for the treatment of inflammatory diseases with a polymicrobial etiology. P. gingivalis has been noted to have a different way of interacting with the innate immune response of the host compared to other pathogenic bacteria, which is a recognized feature that inhibits CXCL8 expression. Objective The aim of the study was to determine if P. gingivalis infection modulates the inflammatory response of gingival stromal stem cells (G-MSSCs), including the release of CXCL8, and the expression of TLRs and if immunomodulatory L. rhamnosus ATCC9595 could prevent CXCL8 inhibition in experimental inflammation. Material and Methods G-MSSCs were pretreated with L. rhamnosus ATCC9595 and then stimulated with P. gingivalis ATCC33277. CXCL8 and IL-10 levels were investigated with ELISA and the TLR-4 and 2 were determined through flow cytometer analysis. Results CXCL8 was suppressed by P. gingivalis and L. rhamnosus ATCC9595, whereas incubation with both strains did not abolish CXCL8. L. rhamnosus ATCC9595 scaled down the expression of TLR4 and induced TLR2 expression when exposed to P. gingivalis stimulation (p<0.01). Conclusions These findings provide evidence that L. rhamnosus ATCC9595 can modulate the inflammatory signals and could introduce P. gingivalis to immune systems by inducing CXCL8 secretion.

Magnetic-Based Cell Isolation Technique for the Selection of Stem Cells

Magnetic-activated cell sorting (MACS) is the technology that is recently used as a magnetic-based cell isolation/purification technique. This technique enables the isolation and selection of germ, hematopoietic, and somatic stem cells including skin stem cells (SkSCs). Here, we have tried to describe the isolation of stem cells by MACS using CD34 antigen for SkSCs, again CD34 for hematopoietic stem cells (HSCs) and Thy-1 for spermatogonial stem cells (SpSCs). MACS allowed the isolation of CD34+, CD34+, and Thy-1+ human SkSCs, HSCs, and SpSCs with minimum 98% purity.

DICER1 gene and miRNA dysregulation in mesenchymal stem cells of patients with myelodysplastic syndrome and acute myeloblastic leukemia

Multipotent mesenchymal stem cells (MSC) are key components of the bone marrow (BM) microenvironment. The contribution of this microenvironment to the pathophysiology of myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML) is not well defined. A recent study in mice demonstrated that DICER1 gene deletion in osteoprogenitor cells from the BM microenvironment suppressed osteogenic differentiation and induced MDS and AML-like haematological findings. The present study evaluated the expression profiles of microRNAs (miRNAs) and DICER1 gene in BM-derived MSC of patients with AML (n=12), MDS (n=10) and healthy controls (HC) (n=8).miRNA expression profiles were analyzed by microarray and confirmations were performed using quantitative real-time PCR (qRT-PCR). Patient MSC displayed impaired proliferative and differentiation potential compared to HC. DICER1 gene expression was lower in MSC from MDS and AML patients than HC and some differentially expressed miRNAs indicated the potential involvement of DICER1 in the pathogenesis of MDS and AML. qRT-PCR confirmation revealed down-regulated miRNAs (hsa-miR-30d-5p, hsa-miR-222-3p and hsa-miR-30a-3p in MDS; hsa-miR-1275, hsa-miR-4725-5p and hsa-miR-143-3p in AML) and over-expressed miRNAs (hsa-miR-4462 in MDS; hsa-miR-134-5p and hsa-miR-874-3p in AML) in MDS and AML. Thus, our findings validate the results of the aforementioned animal study and demonstrate downregulation of DICER1 gene and abnormal miRNA profile in MDS and AML, which may have implications for understanding MDS and AML pathogenesis and contribute to developing targeted treatment strategies.

Endocannabinoids modulate apoptosis in endometriosis and adenomyosis

Adenomyosis that is a form of endometriosis is the growth of ectopic endometrial tissue within the muscular wall of the uterus (myometrium), which may cause dysmenorrhea and infertility. Endocannabinoid mediated apoptotic mechanisms of endometriosis and adenomyosis are not known. We hypothesized that the down regulation of endocannabinoid receptors and/or alteration in their regulatory enzymes may have a direct role in the pathogenesis of endometriosis and adenomyosis through apoptosis. Endocannabinoid receptors CB1 and CB2, their synthesizing and catabolizing enzymes (FAAH, NAPE-PLD, DAGL, MAGL) and the apoptotic indexes were immunohistochemically assessed in endometriotic and adenomyotic tissues. Findings were compared to normal endometrium and myometrium. Endometrial adenocarcinoma (Ishikawa) and ovarian endometriosis cyst wall stromal (CRL-7566) cell lines were furthermore cultured with or without cannabinoid receptor agonists. The IC50 value for CB1 and CB2 receptor agonists was quantified. Cannabinoid agonists on cell death were investigated by Annexin-V/Propidium iodide labeling with flow cytometry. CB1 and CB2 receptor levels decreased in endometriotic and adenomyotic tissues compared to the control group (p=0,001 and p=0,001). FAAH, NAPE-PLD, MAGL and DAGL enzyme levels decreased in endometriotic and adenomyotic tissues compared to control (p=0,001, p=0,001, p=0,001 and p=0,002 respectively). Apoptotic cell indexes both in endometriotic and adenomyotic tissues also decreased significantly, compared to the control group (p=0,001 and p=0,001). CB1 and CB2 receptor agonist mediated dose dependent fast anti-proliferative and pro-apoptotic effects were detected in Ishikawa and ovarian endometriosis cyst wall stromal cell lines (CRL-7566). Endocannabinoids are suggested to increase apoptosis mechanisms in endometriosis and adenomyosis. CB1 and CB2 antagonists can be considered as potential medical therapeutic agents for endometriosis and adenomyosis.

Stem Cell Therapy and Orthopedics

Stem cells obtained from various sources in the body and during different stages of development form the basis of cellular therapy and are often studied in the field of orthopedic regenerative medicine. Parameters such as potential, source, route of administration, and desired dose of stem cells to be used should be selected according to the type of regeneration, and research and application should be conducted with this in mind. This chapter details the general characteristics of stem cells, sources of stem cells, and the advantages and disadvantages of the various sources of stem cells. Detailed specifications of adult stem cells in the group of mesenchymal stem cells, which have more advantages in the field of orthopedics than other stem cells, are provided. Briefly, induced pluripotent stem cells and tissue engineering studies are discussed and examples of orthopedic studies with stem cells are provided.