Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.1.3.1 (alkaline phosphatase)
47,916 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Tissue-engineered bone regeneration offers new therapeutic options in the treatment of patients with fractures. Due to the changes in the hormone levels, elderly women are most affected by bone fractures and thus constitute one of the future target groups of cell-based bone therapy. For designing cell-based therapy approaches, a better understanding of individual-dependent variations in bone-derived cells of the host is required. In this study, a simple, high-yield procedure is described for the collection of cells from bone tissue of a high number of elderly women. The cultured cells display stem cell characteristics indicated by the presence of a CD13+, CD44+, CD90+, CD147+, CD14-, CD34-, CD45- and CD144- cell populations and by a stable undifferentiated phenotype as well as by the ability to proliferate extensively while retaining the potential to differentiate along the osteoblastic lineage even after 27 cell doublings. A high variability in the number of cell-forming units (CFUs) within a donor population of 34 samples, in the morphology within 50 donors, in the expression of alkaline phosphatase within 15 samples and in the responsiveness to BMP-2 was evident, but no age-related correlation could be found. In conclusion, the data indicate that individual variations in cell number, cell morphology and in the osteogenic potential of progenitor cells of the patient may be relevant for a successful treatment of bone fractures in the elderly by cell-based therapy approaches.
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PMID:Properties of human trabecular bone cells from elderly women: implications for cell-based bone engraftment. 1529 80

Bone marrow-derived mesenchymal stem cells (MSC) have been defined as primitive, undifferentiated cells, capable of self-renewal and with the ability to give rise to different cell lineages, including adipocytes, osteocytes, fibroblasts, chondrocytes, and myoblasts. MSC are key components of the hematopoietic microenvironment. Several studies, including some from our own group, suggest that important quantitative and functional alterations are present in the stroma of patients with myelodysplasia (MDS). However, in most of such studies the stroma has been analyzed as a complex network of different cell types and molecules, thus it has been difficult to identify and characterize the cell(s) type(s) that is (are) altered in MDS. In the present study, we have focused on the biological characterization of MSC from MDS. As a first approach, we have quantified their numbers in bone marrow, and have worked on their phenotypic (morphology and immunophenotype) and cytogenetic properties. MSC were obtained by a negative selection procedure and cultured in a MSC liquid culture medium. In terms of morphology, as well as the expression of certain cell markers, no differences were observed between MSC from MDS patients and those derived from normal marrow. In both cases, MSC expressed CD29, CD90, CD105 and Prolyl-4-hydroxylase; in contrast, they did not express CD14, CD34, CD68, or alkaline phosphatase. Interestingly, in five out of nine MDS patients, MSC developed in culture showed cytogenetic abnormalities, usually involving the loss of chromosomal material. All those five cases also showed cytogenetic abnormalities in their hematopoietic cells. Interestingly, in some cases there was a complete lack of overlap between the karyotypes of hematopoietic cells and MSC. To the best of our knowledge, the present study is the first in which a pure population of MSC from MDS patients is analyzed in terms of their whole karyotype and demonstrates that in a significant proportion of patients, MSC are cytogenetically abnormal. Although the reason of this is still unclear, such alterations may have an impact on the physiology of these cells. Further studies are needed to assess the functional integrity of MDS-derived MSC.
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PMID:Mesenchymal stem cells in myelodysplastic syndromes: phenotypic and cytogenetic characterization. 1560 71

Although neuroepithelial tubules (NET) often are a component of immature teratoma (IT), they are not always required for diagnosis. Other somatic elements are sufficient and often verified with immunohistochemical stain. This study was designed to determine the definition of immaturity versus fetal ontogeny, using several molecular markers in IT. It is our contention that IT is equivalent to an embryonic stage less than a fertilization age (FA) of 8 weeks, and a mature teratoma (MT) to a fetal stage later than a FA of 8 weeks, whereas an embryonal carcinoma (Eca) matches a pre-embryonic stage earlier than a FA of 2 weeks. The teratomatous components used as a roadmap to evaluate maturity included: a lobular structure of primitive endodermal tubules (FA 4 to 6 weeks), a ventricle-lined cortical plate (FA 9 weeks), a complex papillary choroid plexus (FA 10 weeks), melanin deposition in hair follicles (FA 15 weeks), and the bell stage of odontogenesis (FA 19 weeks). The teratomatous components of 25 resected ovarian solid teratoma samples were compared with fetal ontogeny. For an immunohistochemical analysis, the CD30, CD34, CD99, bcl-2, alpha-fetoprotein (AFP), and placenta-like alkaline phosphatase (PLAP) were assessed. The AFP and Ki-1 were positive in the embryoid body, which was identified at a FA less than 4 weeks in Eca. The AFP was positive in the primitive endodermal components and some of the squamous epithelium in IT. The CD99 and bcl-2 were selectively stained in the primitive NET, which was detected no later than a FA of 6 weeks. The CD34 and bcl-2 were positive in the immature-looking precartilage blastomatous components, which proved useful for detecting immature cartilage, corresponding to a FA of 5 to 6 weeks. The ontogeny of IT was found to correspond to the embryonic stage at a FA of 2 to 8 weeks, and CD99, CD34, bcl-2, AFP, CD30, and PLAP could be used as supportive tools to define IT. This new grading system could be more scientific and more reproducible in any spectra of teratoma.
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PMID:Diagnostic challenge of fetal ontogeny and its application on the ovarian teratomas. 1578 74

Human bone marrow-derived mesenchymal cells contain mesenchymal stem cells (MSCs), which are well known for their osteo/chondrogenic potential and can be used for bone reconstruction. This article reports the viability of cryopreserved human mesenchymal cells and a comparison of the osteogenic potential between noncryopreserved and cryopreserved human mesenchymal cells with MSC-like characteristics, derived from the bone marrow of 28 subjects. The viability of cryopreserved mesenchymal cells was approximately 90% regardless of the storage term (0.3 to 37 months). It is clear by fluorescence-activated cell sorter analysis that the cell surface antigens of both noncryopreserved and cryopreserved mesenchymal cells were negative for hematopoietic cell markers such as CD14, CD34, CD45, and HLA-DR but positive for mesenchymal characteristics such as CD29 and CD105. To monitor the osteogenic potential of the cells, such as alkaline phosphatase (ALP) activity and in vitro mineralization, a subculture was conducted in the presence of dexamethasone, ascorbic acid, and glycerophosphate. No difference in osteogenic potential was found between cells with or without cryopreservation treatment. In addition, cells undergoing long-term cryopreservation (about 3 years) maintained high osteogenic potential. In conclusion, cryopreserved as well as noncryopreserved human mesenchymal cells could be applied for bone regeneration in orthopedics.
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PMID:Viability and osteogenic potential of cryopreserved human bone marrow-derived mesenchymal cells. 1599 8

Stem cells were obtained from deciduous dental pulp of healthy subjects, aged 6-10 years. This stem cell population was cultured, expanded, and specifically selected, detecting using a FACsorter, c-kit, CD34, and STRO-1 antigen expression. Then, c-kit+/CD34+/STRO-1+ cells were replaced in the culture medium added of 20% FBS, leading to osteoblast differentiation. In fact, these cells, after a week, showed a large positivity for CD44, osteocalcin, and RUNX-2 markers. To achieve an adipocytic differentiation, cells, after sorting, were challenged with dexamethason 10(-8) mM in the same culture medium. To obtain myotube fusion, sorted cells were co-cultured in ATCC medium with mouse myogenic C2C12 cells and, after a week, human stem cell nuclei were found to be able to fuse, forming myotubes. Differentiated osteoblasts, as assessed by a large positivity to several specific antibodies, after 30 days of culture and already in vitro, started to secrete an extracellular mineralized matrix, which, 2 weeks later, built a considerable number of 3D woven bone samples, which showed a strong positivity to alkaline phosphatase (ALP), alizarin red, calcein, other than to specific antibodies. These bone samples, after in vivo transplantation into immunosuppressed rats, were remodeled in a lamellar bone containing entrapped osteocytes. Therefore, this study provides strong evidence that human deciduous dental pulp is an approachable "niche" of stromal stem cells, and that it is an ideal source of osteoblasts, as well as of mineralized tissue, ready for bone regeneration, transplantation, and tissue-based clinical therapies.
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PMID:An approachable human adult stem cell source for hard-tissue engineering. 1622 4

In this study, the osteoinductive and cell-binding properties of three different resorbable polymers were evaluated by human mesenchymal stem cells (MSCs). MSCs were isolated, expanded, and cultivated onto resorbable D,D,L,L-polylactide (PLLA), collagen I/III, and polygalactin-910/polydioxanone (PGPD) scaffolds in vitro. To evaluate the influence of dexamethasone, ascorbic acid, and beta-glycerolphosphate (DAG) on osteoblast differentiation, MSCs were incubated in a DAG-enriched medium. After a 28-day period in vitro, the cellular loaded polymers were digested enzymatically by papain and HCl. The Ca(2+) content of the biomembranes was evaluated by an o-kresolphthalein-complexon reaction via photometer. A PicoGreen assay was performed for dsDNA quantification. Significant differences between the number of adherent MSCs were documented (collagen > PLLA > PGPD). Compared to the initial number of adherent cells, all biomaterials induced a significant decrease in cellular adherence after 28 days in vitro. The presence of DAG-enriched culture medium stimulated the cellular proliferation for PLLA and slightly for PGPD, whereas cell proliferation was inhibited when MSCs were cultivated onto collagen I/III. In comparison with the control groups, all biomaterials (PLLA, PGPD, and collagen I/III) showed a significant increase in local Ca(2+) accumulation under DAG stimulation after 28 days in vitro. Furthermore, collagen I/III and PLLA scaffolds showed osteoinductive properties without DAG stimulation. These results were verified by immunocytochemical stainings against osteoblast-typical markers (osteopontin and alkaline phosphatase) and completed by calcified matrix detection (von Kossa staining). MSCs were identified by CD105 and CD13 antigen expression. Corresponding to an absence of CD34, CD45, and collagen II expression, we found no chondrogenic or hematopoietic cell differentiation. The results indicate significant differences for the proliferation, differentiation, adherence, and Ca(2+) accumulation between the tested polymers in a MSC culture.
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PMID:Proliferation and osteogenic differentiation of mesenchymal stem cells cultured onto three different polymers in vitro. 1624 81

Growth hormone (GH) regulates many of the factors responsible for controlling the development of bone marrow progenitor cells (BMPCs). The aim of this study was to elucidate the role of GH in osteogenic differentiation of BMPCs using GH receptor null mice (GHRKO). BMPCs from GHRKO and their wild-type (WT) littermates were quantified by flow cytometry and their osteogenic differentiation in vitro was determined by cell morphology, real-time RT-PCR, and biochemical analyses. We found that freshly harvested GHRKO marrow contains 3% CD34 (hematopoietic lineage), 43.5% CD45 (monocyte/macrophage lineage), and 2.5% CD106 positive (CFU-F/BMPC) cells compared to 11.2%, 45%, and 3.4% positive cells for (WT) marrow cells, respectively. When cultured for 14 days under conditions suitable for CFU-F expansion, GHRKO marrow cells lost CD34 positivity, and were markedly reduced for CD45, but 3- to 4-fold higher for CD106. While WT marrow cells also lost CD34 expression, they maintained CD45 and increased CD106 levels by 16-fold. When BMPCs from GHRKO mice were cultured under osteogenic conditions, they failed to elongate, in contrast to WT cells. Furthermore, GHRKO cultures expressed less alkaline phosphatase, contained less mineralized calcium, and displayed lower osteocalcin expression than WT cells. However, GHRKO cells displayed similar or higher expression of cbfa-1, collagen I, and osteopontin mRNA compared to WT. In conclusion, we show that GH has an effect on the proportions of hematopoietic and mesenchymal progenitor cells in the bone marrow, and that GH is essential for both the induction and later progression of osteogenesis.
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PMID:Role of growth hormone receptor signaling in osteogenesis from murine bone marrow progenitor cells. 1625 60

Previous studies have reported that mesenchymal stem cells (MSC) may be isolated from the synovial membrane by the same protocol as that used for synovial fibroblast cultivation, suggesting that MSC correspond to a subset of the adherent cell population, as MSC from the stromal compartment of the bone marrow (BM). The aims of the present study were, first, to better characterize the MSC derived from the synovial membrane and, second, to compare systematically, in parallel, the MSC-containing cell populations isolated from BM and those derived from the synovium, using quantitative assays. Fluorescent-activated cell sorting analysis revealed that both populations were negative for CD14, CD34 and CD45 expression and that both displayed equal levels of CD44, CD73, CD90 and CD105, a phenotype currently known to be characteristic of BM-MSC. Comparable with BM-MSC, such MSC-like cells isolated from the synovial membrane were shown for the first time to suppress the T-cell response in a mixed lymphocyte reaction, and to express the enzyme indoleamine 2,3-dioxygenase activity to the same extent as BM-MSC, which is a possible mediator of this suppressive activity. Using quantitative RT-PCR these data show that MSC-like cells from the synovium and BM may be induced to chondrogenic differentiation and, to a lesser extent, to osteogenic differentiation, but the osteogenic capacities of the synovium-derived MSC were significantly reduced based on the expression of the markers tested (collagen type II and aggrecan or alkaline phosphatase and osteocalcin, respectively). Transcription profiles, determined with the Atlas Human Cytokine/Receptor Array, revealed discrimination between the MSC-like cells from the synovial membrane and the BM-MSC by 46 of 268 genes. In particular, activin A was shown to be one major upregulated factor, highly secreted by BM-MSC. Whether this reflects a different cellular phenotype, a different amount of MSC in the synovium-derived population compared with BM-MSC adherent cell populations or the impact of a different microenvironment remains to be determined. In conclusion, although the BM-derived and synovium-derived MSC shared similar phenotypic and functional properties, both their differentiation capacities and transcriptional profiles permit one to discriminate the cell populations according to their tissue origin.
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PMID:Transcriptional profiles discriminate bone marrow-derived and synovium-derived mesenchymal stem cells. 1627 84

Earlier reports on a putative precursor cell population in adipose tissue showed differentiation along several mesodermal lineages, leading some to think that adipose tissue can be a source of cells applicable in regenerative medicine. However, characterizations of these adipose-derived precursor cells (ADPC) in the 3-dimensional (3-D) environment, especially within the area of bone-specific composite scaffolds, have been lacking. In this study, ADPC plated on culture flasks or seeded on medical grade polycaprolactone-tricalcium phosphate scaffolds (mPCL-CaP) were able to differentiate along the osteogenic lineages in both 2-D and 3-D environments as assessed with immunohistochemistry of osteo-related proteins, reverse transcriptase-polymerase chain reactions and alkaline phosphatase assay. The mPCL-CaP scaffolds provided adipose-derived cells (ADC) with a suitable environment as determined by DNA and metabolic assays, light, confocal and scanning electron microscopy. Flow cytometry revealed ADC to be CD29+, CD44+, CD73+, CD90+ and CD14-, CD31-, CD34-, CD45-, CD71-, and therefore showed the absence of hematopoietic stem cells but possibly the presence of pericytes and mescenchymal stem cells with osteogenic potential. The results of this study demonstrated the potential of using ADPC in combination with mPCL-CaP scaffolds for bone regenerative medicine.
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PMID:Characterization of osteogenically induced adipose tissue-derived precursor cells in 2-dimensional and 3-dimensional environments. 1665 24

Follicular dendritic cells (FDC) are involved in the presentation of native Ags to B cells during the secondary immune response. Some authors consider FDC to be hemopoietic cells, whereas others believe them to be mesenchymal cells. The low proportion of FDC in the lymphoid follicle, together with technical difficulties in their isolation, make these cells difficult to study. We show that Fibroblast Medium can be used successfully to isolate and maintain FDC lines. In this culture medium, we obtained 18 FDC lines from human tonsils, which proliferated for as long as 18 wk and showed a stable Ag phenotype as detected by flow cytometry and RT-PCR. FDC lines were CD45-negative and expressed Ags associated to FDC (CD21, CD23, CD35, CD40, CD73, BAFF, ICAM-1, and VCAM-1) and Ags specific for FDC (DRC-1, CNA.42, and HJ2). These cell lines were also able to bind B cells and secrete CXCL13, functional activities characteristic of FDC. Nevertheless, the additional expression of STRO-1, together with CD10, CD13, CD29, CD34, CD63, CD73, CD90, ICAM-1, VCAM-1, HLA-DR, alkaline phosphatase, and alpha-smooth muscle actin (alpha-SM actin) indicated that FDC are closely related to bone marrow stromal cell progenitors. The expression of alpha-SM actin also relates FDC with myofibroblasts. Like myofibroblasts, FDC lines expressed stress fibers containing alpha-SM actin and were able to contract collagen gels under the effect of TGFbeta1 and platelet-derived growth factor. These findings suggest that FDC are a specialized form of myofibroblast and derive from bone marrow stromal cell progenitors.
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PMID:Follicular dendritic cells are related to bone marrow stromal cell progenitors and to myofibroblasts. 1678 23


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