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)

Osteoclast function is important in the development of renal osteodystrophy (ROD). Osteoclast activity is modulated by the osteoprotegerin ligand-osteoprotegerin (OPGL/OPG) system. In the present study, we checked levels of serum OPG and soluble OPGL in dialyzed patients and correlated those levels with routinely measured parameters of bone metabolism. The study was carried out in 39 patients on hemodialysis (HD) and 29 on peritoneal dialysis (PD). The control group included 13 healthy volunteers. Patients on HD had lower OPGL (p = 0.027) and higher OPG (p = 0.000) levels than control subjects did [OPGL: 0.6 pmol/L (median) and 0.0 - 10.0 pmolL (range) vs. 1.9 pmo1/L (median) and 0.0 - 10.5 pmol/L (range); OPG: 7.7 pmol/L (median) and 0.9 - 16.5 pmol/L (range) vs. 2.2 pmol/L (median) and 1.0- 3.9 pmol/L (range)]. Patients on PD differed from controls only in OPG level [4.0 pmol/L (median) and 2.1 - 13.4 pmol/L (range), p = 0.043]. Patients on HD and on PD both had a lower OPGL/OPG ratio than did the control subjects [HD: 0.09 (median) and 0.00 - 1.45 (range), p = 0.000; PD: 0.35 (median) and 0.00 - 3.89 (range), p = 0.018; controls: 1.07 (median) and 0.00 - 5.14 (range)]. Patients on HD did not differ from patients on PD in levels of OPGL and OPGL/OPG, but they had a higher OPG level (p = 0.001). Patients on HD also showed significantly higher total alkaline phosphatase (ALP) activity and higher inorganic phosphate (iP), but lower total calcium and blood pH. In PD patients, OPGL and OPG both correlated with pH (OPGL positively and OPG negatively). In HD patients, OPGL showed a positive correlation with ALP and a negative correlation with calcium; OPG correlated positively with iP In 36 patients on HD (92.3%) and 15 patients on PD (51.7%), OPG was elevated above the normal value. Differences in serum OPG and OPGL/OPG ratio between groups of dialyzed patients and of control subjects indicate that ROD is more advanced in HD patients than in PD patients. Higher serum OPG and lower serum OPGL in the HD group is probably an effect of higher osteoclast activity. In about 50% of PD patients, osteoclast function is also disturbed, as indicated by elevated OPG levels.
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PMID:Using the ratio of serum osteoprotegerin ligand to osteoprotegerin to evaluate renal osteodystrophy in dialysis patients. 1668 16

The cause of the polyneuropathy, organomegaly, endocrinopathy, monoclonal plasma cell disorder and skin changes (POEMS) syndrome is currently unknown, but increased levels of vascular endothelial growth factor (VEGF) appear to play a pathogenetic role. Osteosclerotic bone lesions are a characteristic finding in POEMS, but there are no data about the specific role of various molecules that control bone remodeling in patients with POEMS. Serum levels of angiogenic cytokines (VEGF, angiogenin, angiopoietin-2, and basic fibroblast growth factor) along with a series of bone remodeling indices (C-telopeptide of type I collagen, bone-alkaline phosphatase [bALP], osteocalcin [OC], soluble receptor activator of nuclear factor-kappaB ligand [RANKL], osteoprotegerin [OPG], and macrophage inflammatory protein-1alpha) were measured in 2 patients with POEMS before and after high-dose therapy (HDT) with autologous stem cell transplantation and in age- and sex-matched controls. Increased VEGF levels before HDT were reduced significantly after treatment, although levels of the other angiogenetic factors did not differ from that of controls and were less influenced by HDT. Serum RANKL levels were increased before HDT, whereas OPG levels were within the levels of healthy controls, resulting in an abnormal soluble RANKL to OPG ratio. Levels of bone resorption markers (C-telopeptide of type I collagen) were very low or undetectable before HDT, although bALP and OC levels were similar to that of controls. After HDT, soluble RANKL levels decreased, OPG remained rather stable, bone resorption markers increased to levels of normal individuals, bALP levels were rather unchanged, and OC levels increased. Decreasing VEGF levels parallel clinical improvement, and the restoration of normal bone metabolism follows HDT.
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PMID:Angiogenetic factors and biochemical markers of bone metabolism in POEMS syndrome treated with high-dose therapy and autologous stem cell support. 1687 74

Mechanical unloading causes detrimental effects on the skeleton, but the underlying mechanisms are still unclear. We investigated the effect of microgravity on osteoblast ability to regulate osteoclastogenesis. Mouse osteoblast primary cultures were grown for 24 h at unit gravity or under simulated microgravity, using the NASA-developed Rotating Wall Vessel bioreactor. Conditioned media (CM) from osteoblasts subjected to microgravity increased osteoclastogenesis and bone resorption in mouse bone marrow cultures. In these osteoblasts, the RANKL/OPG ratio was higher relative to 1g. Consistently, treatment with high concentrations of OPG-inhibited osteoclastogenesis and bone resorption in the presence of CM arising from osteoblasts cultured under microgravity. Microgravity failed to affect osteoblast differentiation and function in the time frame of the experiment, as we found no effect on alkaline phosphatase mRNA and activity, nor on Runx2, osteocalcin, osteopontin, and collagen1A2 mRNA expression. In contrast, microgravity induced a time dependent increase of ERK-1/2 phosphorylation, while phospho-p38 and phospho-JNK remained unchanged. Apoptosis, revealed by bis-benzimide staining, was similar among the various gravity conditions, while it was increased under microgravity after treatment with the MEK-1/2 inhibitor, PD98059, suggesting a protection role by ERK-1/2 against cell death. In conclusion, microgravity is capable to indirectly stimulate osteoclast formation and activity by regulating osteoblast secretion of crucial regulatory factors such as RANKL and OPG. We hypothesize that this mechanism could contribute to bone loss in individuals subjected to weightlessness and other unloading conditions.
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PMID:Modeled microgravity stimulates osteoclastogenesis and bone resorption by increasing osteoblast RANKL/OPG ratio. 1692 71

Aseptic loosening of a joint prosthesis is associated with remodelling of bone tissue in the vicinity of the prosthesis. In the present study, we investigated the effects of synovial fluid (SF) from patients with a loose prosthetic component and periprosthetic osteolysis on osteoclast and osteoblast activities in vitro and made comparisons with the effects of SF from patients with osteoarthritis (OA). Bone resorption was assessed by the release of calcium 45 (45Ca) from cultured calvariae. The mRNA expression in calvarial bones of molecules known to be involved in osteoclast and osteoblast differentiation was assessed using semi-quantitative reverse transcription-polymerase chain reaction (PCR) and real-time PCR. SFs from patients with a loose joint prosthesis and patients with OA, but not SFs from healthy subjects, significantly enhanced 45Ca release, effects associated with increased mRNA expression of calcitonin receptor and tartrate-resistant acid phosphatase. The mRNA expression of receptor activator of nuclear factor-kappa-B ligand (rankl) and osteoprotegerin (opg) was enhanced by SFs from both patient categories. The mRNA expressions of nfat2 (nuclear factor of activated T cells 2) and oscar (osteoclast-associated receptor) were enhanced only by SFs from patients with OA, whereas the mRNA expressions of dap12 (DNAX-activating protein 12) and fcrgamma (Fc receptor common gamma subunit) were not affected by either of the two SF types. Bone resorption induced by SFs was inhibited by addition of OPG. Antibodies neutralising interleukin (IL)-1alpha, IL-1beta, soluble IL-6 receptor, IL-17, or tumour necrosis factor-alpha, when added to individual SFs, only occasionally decreased the bone-resorbing activity. The mRNA expression of alkaline phosphatase and osteocalcin was increased by SFs from patients with OA, whereas only osteocalcin mRNA was increased by SFs from patients with a loose prosthesis. Our findings demonstrate the presence of a factor (or factors) stimulating both osteoclast and osteoblast activities in SFs from patients with a loose joint prosthesis and periprosthetic osteolysis as well as in SFs from patients with OA. SF-induced bone resorption was dependent on activation of the RANKL/RANK/OPG pathway. The bone-resorbing activity could not be attributed solely to any of the known pro-inflammatory cytokines, well known to stimulate bone resorption, or to RANKL or prostaglandin E2 in SFs. The data indicate that SFs from patients with a loose prosthesis or with OA stimulate bone resorption and that SFs from patients with OA are more prone to enhance bone formation.
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PMID:Effects on osteoclast and osteoblast activities in cultured mouse calvarial bones by synovial fluids from patients with a loose joint prosthesis and from osteoarthritis patients. 1731 39

Icariin, a principal flavonoid glycoside in Herba Epimedii, is hypothesized to possess beneficial effects on bone mass. Icariin is metabolized to icariside II and then to icaritin in vivo. In the present study, we investigated the in vitro effects of icariin, icariside II and icaritin on both osteoblasts and osteoclasts. After treatment with these compounds at concentrations 10(-5)-10(-8) mol/l, osteoblasts were examined for proliferation, alkaline phosphatase activity, osteocalcin secretion and matrix mineralization, as well as expression levels of bone-related proteins. The formation of osteoclasts was assessed by counting the number of multinucleated TRAP-positive cells. The activity of isolated rat osteoclasts was evaluated by measuring pit area, actin rings and superoxide generation. Icariside II and icaritin increased the mRNA expression of ALP, OC, COL-1 and OPG, but suppressed that of RANKL. In addition, these compounds reduced the number of multinucleated TRAP-positive cells and the osteoclastic resorption area. Also decreases were observed in superoxide generation and actin ring formation that are required for osteoclast survival and bone resorption activity. These findings suggest that icaritin, which was more potent than icariin and icariside II, enhanced the differentiation and proliferation of osteoblasts, and facilitated matrix calcification; meanwhile it inhibited osteoclastic differentiation in both osteoblast-preosteoclast coculture and osteoclast progenitor cell culture, and reduced the motility and bone resorption activity of isolated osteoclasts.
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PMID:Icaritin and its glycosides enhance osteoblastic, but suppress osteoclastic, differentiation and activity in vitro. 1776 2

Recent evidences suggest that the activation of peroxisome proliferator-activated receptor (PPAR)-gamma, which is an important transcriptional factor in adipocyte differentiation, also plays an important role in the bone microenvironment. The objective of the study was to clarify whether Pro12Ala polymorphism was related to the serum OPG levels and bone mineral metabolism in healthy Korean women. In 239 Korean women (mean age 51 years), who participated in medical check-up program in a health promotion center, anthropometric measurements, lumbar spine and femoral neck bone mineral density (BMD), bone turnover markers, such as serum total alkaline phosphatase (ALP) levels, urine deoxypyridinoline levels, and 24-h urine calcium excretion were measured. Serum levels of OPG were measured with ELISA method. DNAs were extracted from the samples and the genotyping of the Pro12Ala polymorphism (rs1801282) in the PPAR-gamma gene was performed via an allelic discrimination assay using a TaqMan probe. In addition, we examined the haplotype analysis between two polymorphisms of PPAR-gamma gene, Pro12Ala in exon B and C161T in exon 6 (rs3856806). Allelic frequencies were 0.950 for Pro allele and 0.050 for Ala allele, which was in compliance with Hardy- Weinberg equilibrium, and there was no Ala12Ala genotype among the genotyped subjects. Mean serum OPG level was significantly lower (P=0.035), and serum total ALP was significantly higher (P=0.014) in the Pro12Ala genotype group compared with the Pro12Pro genotype group, which were consistently significant even after adjustment for weight, height, and serum follicle stimulating hormone (FSH). In multiple regression analysis with serum OPG as the dependent variable and age, weight, ALP, femoral neck BMD and Pro12Ala genotype included in the model, only Pro12Ala genotype was significant determinant of serum OPG level (b=??0.136, P=0.035). The haplotype analysis with C161T polymorphism revealed that subjects with Ala and T alleles showed significantly lower serum OPG levels compared with those with Pro12Pro/CC genotype, which were consistently significant even after adjustment for age, weight, height and FSH (P=0.010). This result suggests statistically significant association of Pro12Ala polymorphisms with serum OPG levels in Korean females.
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PMID:The association of Pro12Ala polymorphism of peroxisome proliferator-activated receptor-gamma gene with serum osteoprotegerin levels in healthy Korean women. 1816 Aug 40

Primary pachydermoperiostosis (PDP) is a rare syndrome, characterized by digital clubbing, periostosis, and pachydermia. We have evaluated biochemical bone turnover markers, including components of interleukin-6 (IL-6) and osteoprotegerin/receptor activator of nuclear factor (NF)-kappaB ligand (OPG/RANKL) systems, in an 18-year-old man affected by primary PDP. The acute phase of the disease was characterized in our patient by high serum levels of IL-6 and RANKL. The observed high serum levels of these parameters are associated with increased values in markers of bone resorption (degradation products of C-terminal telopeptides of type-I collagen and urinary hydroxyproline/creatinine ratio) and reduced serum levels of bone alkaline phosphatase, a marker of bone formation. Serum levels of osteotrophic hormones were in the normal range. Our data suggest that, despite the radiographic findings, the acute phase of primary PDP is characterized by increased bone resorption, probably mediated by IL-6 and RANKL.
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PMID:Interleukin (IL)-6 and receptor activator of nuclear factor (NF)-kappaB ligand (RANKL) are increased in the serum of a patient with primary pachydermoperiostosis. 1846 59

The OPG/RANKL system in primary cultures of human osteoblasts has been studied by different authors. However, very few studies have been performed on gene expression of RANKL and OPG at different stages of maturation on human osteoblast cultures. The effect of 17- beta-estradiol and 1,25dihydroxyvitamin D3 on the OPG/RANKL system is not known during the different states of cellular maturation. In this work we quantified OPG and RANKL protein levels (ELISA) and the mRNA of OPG, RANKL, collagen type I, alkaline phosphatase, and osteocalcin (semi-quantitative RT-PCR) in human osteoblasts. We analyzed these in basal conditions and after incubation with 17- beta-estradiol and 1,25dihydroxyvitamin D3 in the first and second phases. We found that OPG secretion and expression levels increased throughout cellular growth. RANKL proteins were detected only in the first stage, and the expression increased throughout the first phase. Thus, the RANKL/OPG ratio was higher in immature osteoblasts than in mature osteoblasts. The evolution of RANKL gene expression was related to collagen I and alkaline phosphatase, while OPG was related to osteocalcin. We observed no modifications after estradiol and 1,25dihydroxyvitamin D3 treatment. Our results suggest that the OB is a positive stimulator at precocious stages of differentiation on osteoclastogenic modulates.
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PMID:Modifying RANKL/OPG mRNA expression in differentiating and growing human primary osteoblasts. 1893 23

Although the effects of coumestrol on osteoblasts and osteoclasts can be summarized as increasing the bone density and preventing bone resorption, direct and detailed effects of coumestrol on bone marrow stromal cells remain obscure. In the present study, the effects of coumestrol on proliferation and osteoblastic differentiation of rat bone marrow stromal cells (BMSCs) have been investigated; the regulative effect of coumestrol on BMSCs and skeletal system has also been discussed. The results showed that treatment with coumestrol increased cellular activities (analyzed by MTT assay), alkaline phosphatase (ALP), type I collagen and osteocalcin (OCN) activity as well as the protein and gene expression of OPG, gene expression ratio of OPG/RANKL and gene expression of estrogen receptor alpha(ERalpha). These results demonstrate that phytoestrogen coumestrol has a direct enhancing effect on the proliferation and osteogenic differentiation of bone marrow stromal cells, which would lead to stimulation of bone formation, and it can also protect the whole skeletal system by regulating OPG/RANKL expression, and these effects may be mediated by ERalpha.
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PMID:Coumestrol promotes proliferation and osteoblastic differentiation in rat bone marrow stromal cells. 1916 72

Multiple myeloma (MM) is a plasma cell malignancy characterized by a high capacity to induce osteolytic bone lesions. MM patients with osteolytic bone lesions have lower numbers of osteoblasts and decreased bone formation, which plays a critical role in the bone-destructive process. Although the mechanism of estrogen action on bone cells and myeloma cells has been widely investigated, estrogen action on bone cells in MM is unknown. In this study, the effects of the gonadal hormone 17beta-estradiol on cell growth, alkaline phosphatase (ALP) activity, mineralization capacity, and RANKL/OPG ratios in primary rat osteoblasts cultured with MM cell conditioned medium (CM) or co-cultured with RPMI8226 cells were investigated. Treatments of 10(-2) to 10 nM 17beta-estradiol reversed inhibition of proliferation and ALP activity of osteoblasts by myeloma cells in a dose-dependent manner, and 10(-2) to 1 nM 17beta-estradiol reversed inhibition of the mineralization capacity of osteoblasts by myeloma cells. In co-culture experiments with primary rat osteoblasts and myeloma cells, treatments of 10(-2) to 10 nM 17beta-estradiol down-regulated transcription and secretion of RANKL and up-regulated transcription and secretion of OPG in the osteoblasts, reversing the effects of co-cultured myeloma cells. These findings suggest that 17beta-estradiol may temper the inhibitory effects of myeloma cells on osteoblasts and improve RANKL/OPG balance, providing a new agent for treatment of bone disease in myeloma.
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PMID:17beta-Estradiol overcomes human myeloma RPMI8226 cell suppression of growth, ALP activity, and mineralization in rat osteoblasts and improves RANKL/OPG balance in vitro. 1916 63


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