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

---

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

In this study, we present a novel guided bone regeneration (GBR) concept that consists of combining Boneject, a bone substitute containing atelocollagen and bovine hydroxyapatite particles, with thermoplastic, bioresorbable plates (DeltaSystem) known to resist mechanical loading. In rat calvariae, standardized bone defects were filled with Boneject and covered with a convex DeltaSystem plate. Tissue from rats at 1, 2, 4, 8, and 12 weeks postoperation were fixed with an aldehyde solution, and the new bone formed at the defects was histologically assessed. At 1 week, alkaline phosphatase (ALP)-negative cells deriving from the bottom region of the defect could be found up to half the height of the cavity. Boneject particle surfaces in the bottom region revealed an intense osteopontin immunopositivity whereas those in the upper region did not. Tartrate-resistant acid phosphatase (TRAP)-positive osteoclasts accumulated on the surfaces of osteopontin-coated particles. A newly formed, woven-like bone featuring ALP-positive osteoblasts extended from the native bone. At the second week, the newly formed woven bone had surrounded the Boneject particles. Cement lines, which indicate active bone remodeling, could be observed in the new bone despite its immaturity. Four weeks after surgery, the new bone had reached the height of the DeltaSystem plate, and just beneath it a periostin-positive fibrous layer covered the mix of new bone and Boneject particles. By then, despite having acceptable histological features, electron probe microanalyzer (EPMA) and transmission electron microscope (TEM) analyses revealed that the new bone could not be regarded as compact bone. At 8 and 12 weeks, the new bone showed compact bone-like features according to TEM and EPMA assessments. Summarizing, the combination of a bone substitute such as Boneject and a rigid, bioresorbable plate appears to be osteoconductive and to promote bone remodeling, leading to the genesis of a tissue similar to the one that is regarded as the "gold standard" for bone regeneration: the compact bone.
...
PMID:Histological examination of bone regeneration achieved by combining grafting with hydroxyapatite and thermoplastic bioresorbable plates. 1796 88

We investigated porcine dental follicle cells at the early crown-formation stage and examined the behavior of cells grown in a collagen type I (Col-I) matrix. Clone-porcine dental follicle cells (DFC-I) and controls, viz., dental follicle itself, nonclone-dental follicle cells, periodontal ligament cells (PDLC), and bone marrow stromal cells, were obtained from 6-month-old pigs. DFC-I showed a different gene expression pattern from controls by reverse-transcription polymerase chain reaction analysis. In addition, Col-I treatment enhanced DFC-I proliferation and increased their alkaline phosphatase activity compared with nontreated DFC-I. The expression of periostin, biglycan, and osteocalcin (OCN) in cells growing on collagen was upregulated, similar to the pattern seen in PDLC. DFC-I with and without Col-I treatment were combined with beta-tricalcium phosphate particles and implanted into immunodeficient mice. Significant differences were found in the gene expression patterns of bone sialoprotein, OCN, and periostin in both treated and non-treated implants at 2 and/or 4 weeks. The results showed that Col-I induced the mineralization pathway in these cells. Hard tissue formation was observed in both implant types at 8 weeks. Our results suggest that Col-I facilitates the differentiation of DFC-I along the mineralization process.
...
PMID:Collagen type I matrix affects molecular and cellular behavior of purified porcine dental follicle cells. 1799 85

Periostin-like-factor (PLF), an isoform related to Periostin, is expressed in bone, heart, and vascular smooth muscle cells. PLF was detected by immunostaining in mesenchymal cells in the periosteum and in osteoblasts lining trabecular bone, suggesting that PLF has a role in osteogenesis. PLF has a signal peptide and is also secreted from osteoblasts in vitro. To study the function of PLF in osteogenesis, we assessed the effect of PLF on osteoblast proliferation and differentiation in vitro and bone formation in vivo. First, to examine whether PLF regulates osteoblast proliferation in vitro, the CyQUANT cell proliferation assay was performed. PLF over-expression by adenovirus resulted in a significantly higher rate of cell proliferation compared to controls. This finding suggests that PLF promotes osteoblast proliferation in vitro. Second, to test whether PLF mediates osteoblast differentiation in vitro, differentiation markers of osteoblasts, were assessed, including alkaline phosphatase staining and activity, von Kossa staining and calcium deposition. Over-expression of PLF resulted in higher expression and activity of alkaline phosphatase and higher amounts of mineralization and calcium deposition compared to controls. These data suggest that PLF promotes osteoblast differentiation in vitro. Third, to investigate the role of PLF in bone formation in vivo, PLF adenovirus was injected into 6-week-old rat femur bone marrow. Over-expression of PLF resulted in increased bone formation within the marrow cavity. Lastly, in a model of fracture healing, PLF expression is robustly upregulated in callus osteoblasts at post-fracture days 7 and 14. Taken together, these findings suggests that PLF induces bone formation in vivo. We conclude that PLF stimulates bone formation in vivo possibly by promoting osteoblast proliferation and differentiation.
...
PMID:Periostin-like-factor in osteogenesis. 1900 75

The aim of this work was to evaluate the biocompatibility of poly(vinylidene fluoride-trifluoroethylene)/barium titanate (P(VDF-TrFE)/BT) membrane to be used in guided tissue regeneration (GTR). Fibroblasts from human periodontal ligament (hPDLF) and keratinocytes (SCC9) were plated on P(VDF-TrFE)/BT and polytetrafluorethylene membranes at a cell density of 20,000 cells well(-1) and cultured for up to 21 days. Cell morphology, adhesion and proliferation were evaluated in hPDLF and keratinocytes, while total protein content and alkaline phosphatase (ALP) activity were assayed only for hPDLF. Using a higher cell density, real-time polymerase chain reaction (PCR) was performed to assess the expression of typical genes of hPDLF, such as periostin, PDLs17, S100A4 and fibromodulin, and key phenotypic markers of keratinocytes, including involucrin, keratins 1, 10 and 14. Expression of the apoptotic genes bax, bcl-2 and survivin was evaluated for both cultures. hPDLF adhered and spread more on P(VDF-TrFE)/BT, whereas keratinocytes showed a round shape on both membranes. hPDLF adhesion was greater on P(VDF-TrFE)/BT at 2 and 4h, while keratinocyte adhesion was similar for both membranes. Whereas proliferation was significantly higher for hPDLF on P(VDF-TrFE)/BT at days 1 and 7, no signs of keratinocyte proliferation could be noticed for both membranes. Total protein content was greater on P(VDF-TrFE)/BT at 7, 14 and 21 days, and higher levels of ALP activity were observed on P(VDF-TrFE)/BT at 21 days. Real-time PCR revealed higher expression of phenotypic markers of hPDLF and keratinocytes as well as greater expression of apoptotic genes in cultures grown on P(VDF-TrFE)/BT. These results indicate that, by favoring hPDLF adhesion, spreading, proliferation and typical mRNA expression, P(VDF-TrFE)/BT membrane should be considered an advantageous alternative for GTR.
...
PMID:In vitro biocompatibility of poly(vinylidene fluoride-trifluoroethylene)/barium titanate composite using cultures of human periodontal ligament fibroblasts and keratinocytes. 1970 97

Osteoblastic differentiation of human mesenchymal stem cells (hMSC) in monolayer culture is artefactual, lacking an organized bone-like matrix. We present a highly reproducible microwell protocol generating three-dimensional ex vivo multicellular aggregates of telomerized hMSC (hMSC-telomerase reverse transcriptase (TERT)) with improved mimicry of in vivo tissue-engineered bone. In osteogenic induction medium the hMSC were transitioned with time-dependent specification toward the osteoblastic lineage characterized by production of alkaline phosphatase, type I collagen, osteonectin, and osteocalcin. Introducing a 1-2 mm(3) crystalline hydroxyapatite/beta-tricalcium phosphate scaffold generated osteospheroids with upregulated gene expression of transcription factors RUNX2/CBFA1, Msx-2, and Dlx-5. An organized lamellar bone-like collagen matrix, evident by birefringence of polarized light, was deposited in the scaffold concavities. Here, mature osteoblasts stained positively for differentiated osteoblast markers TAZ, biglycan, osteocalcin, and phospho-AKT. Quantification of collagen birefringence and relatively high expression of genes for matrix proteins, including type I collagen, biglycan, decorin, lumican, elastin, microfibrillar-associated proteins (MFAP2 and MFAP5), periostin, and tetranectin, in vitro correlated predictively with in vivo bone formation. The three-dimensional hMSC-TERT/hydroxyapatite-tricalcium phosphate osteospheroid cultures in osteogenic induction medium recapitulated many characteristics of in vivo bone formation, providing a highly reproducible and resourceful platform for improved in vitro modeling of osteogenesis and refinement of bone tissue engineering.
...
PMID:Parameters in three-dimensional osteospheroids of telomerized human mesenchymal (stromal) stem cells grown on osteoconductive scaffolds that predict in vivo bone-forming potential. 2019 44

There is increasing evidence that osteogenic cells are present not only in bone marrow (BM) but also in peripheral blood (PB). Since staining for alkaline phosphatase (AP) identifies osteoprogenitor cells in BM, we sought to further characterize BM versus PB hematopoietic lineage negative (lin-)/AP+ cells and to compare gene expression in PB lin-/AP+ cells from postmenopausal women undergoing rapid versus slow bone loss. PB lin-/AP+ cells were smaller than their BM counterparts, and both were negative for the pan-hematopoietic marker, CD45. BM and PB lin-/AP+ cells were capable of mineralization in vitro. Using whole genome linear amplification followed by quantitative polymerase chain reaction (QPCR) analysis, we found that relative to the BM cells, PB lin-/AP+ cells expressed similar levels of a number of key osteoblast marker genes (runx2, osterix, osteopontin, OPG, periostin), consistent with the PB cells being in the osteoblastic lineage. Importantly, however, compared to the BM cells, PB lin-/AP+ cells expressed lower levels of mRNAs for AP, type I collagen, and for a panel of proliferation markers, but higher levels of osteocalcin, osteonectin, and PTHR1 mRNAs, as well as those for RANKL and ICAM-1, both of which are important in supporting osteoclastogenesis. Using microarray followed by QPCR analysis, we further demonstrated that, compared to postmenopausal women undergoing slow bone loss, PB lin-/AP+ cells from women undergoing rapid bone loss expressed lower levels of mRNAs for hydroxyprostaglandin dehydrogenase, interferon regulator factor 3, Wnt1-induced secreted protein 1, and TGFbeta2, but higher levels of the Smad3 interacting protein, zinc finger DHHC-type containing 4 and col1alpha2. These data thus demonstrate that while PB lin-/AP+ cells express a number of osteoblastic genes and are capable of mineralization, they are a relatively quiescent cell population, both in terms of cell proliferation and matrix synthesis. However, their higher expression of RANKL and ICAM-1 mRNAs as compared to BM lin-/AP+ cells suggests a role for the PB lin-/AP+ cells in regulating osteoclastogenesis that warrants further investigation. Our study also provides "proof-of-concept" for the use of PB lin-/AP+ cells in clinical-investigative studies, and identifies several pathways that could potentially regulate rates of bone loss in postmenopausal women.
...
PMID:Circulating osteogenic cells: characterization and relationship to rates of bone loss in postmenopausal women. 2036 80

We have previously developed a voluntary rat model of highly repetitive reaching that provides an opportunity to study effects of non-weight bearing muscular loads on bone and mechanisms of naturally occurring inflammation on upper limb tissues in vivo. In this study, we investigated the relationship between inflammatory cytokines and matricellular proteins (Periostin-like-factor, PLF, and connective tissue growth factor, CTGF) using our model. We also examined the relationship between inflammatory cytokines, PLF and bone formation processes. Rats underwent initial training for 5 weeks, and then performed a high repetition high force (HRHF) task (12 reaches/min, 60% maximum grip force, 2 h/day, 3 days/week) for 6 weeks. We then examined the effect of training or task performance with or without treatment with a rat specific TNFalpha antibody on inflammatory cytokines, osteocalcin (a bone formation marker), PLF, CTGF, and behavioral indicators of pain or discomfort. The HRHF task decreased grip strength and induced forepaw mechanical hypersensitivity in both trained control and 6-week HRHF animals. Two weeks of anti-TNFalpha treatment improved grip strength in both groups, but did not ameliorate forepaw hypersensitivity. Moreover, anti-TNFalpha treatment attenuated task-induced increases in inflammatory cytokines (TNFalpha, IL-1alpha, and MIP2 in serum; TNFalpha in forelimb bone and muscles) and serum osteocalcin in 6-week HRHF animals. PLF levels in forelimb bones and flexor digitorum muscles increased significantly in 6-week HRHF animals, increases attenuated by anti-TNFalpha treatment. CTGF levels were unaffected by task performance or anti-TNFalpha treatment in 6-week HRHF muscles. In primary osteoblast cultures, TNFalpha, MIP2 and MIP3a treatment increased PLF levels in a dose dependent manner. Also in primary osteoblast cultures, increased PLF promoted proliferation and differentiation, the latter assessed by measuring Runx2, alkaline phosphatase (ALP) and osteocalcin mRNA levels; ALP activity; as well as calcium deposition and mineralization. Increased PLF also promoted cell adhesion in MC3T3-E1 osteoblast-like cell cultures. Thus, tissue loading in vivo resulted in increased TNFalpha, which increased PLF, which then induced anabolic bone formation, the latter results confirmed in vitro.
...
PMID:Role of TNF alpha and PLF in bone remodeling in a rat model of repetitive reaching and grasping. 2045 32

Periodontal-ligament-derived cells (PDL cells) have stem-cell-like properties and, when implanted into periodontal defects in vivo, can induce periodontal regeneration including the formation of new bone, cementum, and periodontal ligament. We have previously demonstrated that PDL cell sheets, harvested from temperature-responsive cell culture dishes, have a great potential for periodontal regeneration. The purpose of this study has been to validate the safety and efficacy of human PDL (hPDL) cell sheets for use in clinical trials. hPDL tissues from three donors were enzymatically digested, and the obtained cells were cultured with media containing autologous serum in a cell-processing center (CPC). The safety and efficacy of hPDL cell sheets were evaluated both in vitro and in vivo. In vitro studies showed that the hPDL cell sheets had high alkaline phosphatase activity and periostin expression (known PDL markers) and no contamination with microorganisms. In vivo studies revealed that hPDL cell sheets, implanted with dentin blocks, induced the formation of cementum and PDL-like tissue in immunodeficient mice. The hPDL cells presented no evidence of malignant transformation. Thus, hPDL cell sheets created in CPCs are safe products and possess the potential to regenerate periodontal tissues.
...
PMID:Assessment of cell sheets derived from human periodontal ligament cells: a pre-clinical study. 2063 35

The gap junction protein connexin43 (Cx43) has been proposed to play key roles in bone differentiation and mineralization, but underlying cellular mechanisms are not totally understood. To further explore roles of Cx43 in these processes, we immortalized calvarial osteoblasts from wild-type and Cx43-null mice using human telomerase reverse transcriptase (hTERT). Osteoblastic (MOB) cell lines were generated from three individual wild-type and three individual Cx43-null mouse calvaria. Average population doubling times of the cell lines were higher than of the primary osteoblasts but did not greatly differ with regard to genotype. Modest to high level of Cx45 expression was detected in MOBs of both genotypes. Most of the cell lines expressed osteoblastic markers [Type I collagen, osteopontin, osteocalcin, parathyroid hormone/parathyroid hormone-related peptide receptor (PTH/PTHrP), periostin (OSF-2), osterix (Osx), runt-related transcription factor 2 (Runx2), alkaline phosphatase (ALP)], and mineralization was comparable to that of primary osteoblasts. Two MOB cell lines from each genotype with most robust maintenance of osteoblast lineage markers were analyzed in greater detail, revealing that the Cx43-null cell lines showed a significant delay in early differentiation (up to 9 days in culture). Matrix mineralization was markedly delayed in one of the Cx43-null lines and slightly delayed in the other. These findings comparing new and very stable wild-type and Cx43-null osteoblastic cell lines define a role for Cx43 in early differentiation and mineralization stages of osteoblasts and further support the concept that Cx43 plays important role in the cellular processes associated with skeleton function.
...
PMID:Characterization of hTERT-immortalized osteoblast cell lines generated from wild-type and connexin43-null mouse calvaria. 2068 67

The regeneration of lost periodontal ligament (PDL) and alveolar bone is the purpose of periodontal tissue engineering. The goal of the present study was to assess the suitability of 3 odontogenic progenitor populations from dental pulp, PDL, and dental follicle for periodontal regeneration when exposed to natural and synthetic apatite surface topographies. We demonstrated that PDL progenitors featured higher levels of periostin and scleraxis expression, increased adipogenic and osteogenic differentiation potential, and pronounced elongated cell shapes on barren root chips when compared with dental pulp and dental follicle cells. When evaluating the effect of surface characteristics on PDL progenitors, natural root surfaces resulted in elongated PDL cell shapes, whereas PDL progenitors on synthetic apatite surfaces were rounded or polygonal. In addition, surface coatings affected PDL progenitor gene expression profiles: collagen I coatings enhanced alkaline phosphatase and osteocalcin expression levels and laminin-1 coatings increased epidermal growth factor (EGF), nestin, cadherin 1, and keratin 8 expression. PDL progenitors seeded on natural tooth root surfaces in organ culture formed new periodontal fibers after 3 weeks of culture. Finally, replantation of PDL progenitor-seeded tooth roots into rat alveolar bone sockets resulted in the complete formation of a new PDL and stable reattachment of teeth over a 6-month period. Together, these findings indicate that periodontal progenitor cell type as well as mineral surface topography and molecular environment play crucial roles in the regeneration of true periodontal anchorage.
...
PMID:Successful periodontal ligament regeneration by periodontal progenitor preseeding on natural tooth root surfaces. 2125 Aug 30


<< Previous 1 2 3 4 Next >>

---