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)

The underlying mechanisms responsible for both cartilage loss and subchondral bone changes in osteoarthritis (OA) remain unknown. It is becoming recognized that the extracellular matrix influences the metabolism of cells both in vivo and in vitro and can modify their responses to external stimuli. Indeed, the glycosaminoglycan/proteoglycan matrix is of major importance for the proliferation and/or differentiation of a number of cells. Here, we determined the potential role of hyaluronic acid (HA) of increasing molecular weight (MW) to alter the expression of metabolic markers and cytokine production by human osteoarthritic (OA) subchondral osteoblasts (Ob). Both 1,25(OH)(2)D(3)-induced alkaline phosphatase activity (ALPase) and osteocalcin release were increased in OA Ob when compared to normal. HA reduced osteocalcin release in OA Ob at MW of 300 and above, whereas HA failed to significantly modify ALPase. Parathyroid hormone (PTH) stimulated cyclic AMP (cAMP) formation by OA Ob. HA had a biphasic effect on this PTH-dependent activity, totally inhibiting cAMP formation at MW of 300 and 800. HA of increasing MW progressively reduced the levels of Prostaglandin E(2) (PGE(2)) and interleukin-6 (IL-6) produced by OA Ob. Interestingly, urokinase plasminogen activator (uPA) and and PA inhibitor-1 (PAI-1) levels were not significantly affected by HA of increasing MW; however, the PAI-1 to uPA ratio showed a slight, yet nonsignificant increase. Surprisingly, uPA activity was increased in OA Ob under the same conditions. Last, HA had no effect on the production of insulin-like growth factor-1 by these cells. Our data suggest that high MW HA can modify cellular parameters in OA Ob that are increased when compared to normal. The effect of HA on inflammatory mediators, such as PGE(2) and IL-6, and on uPA activity is more striking at higher MW as well. Taken together, these results could suggest that HA of increasing MW has positive effects on OA Ob by modifying their biological synthetic capacities.
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PMID:Hyaluronic acid reverses the abnormal synthetic activity of human osteoarthritic subchondral bone osteoblasts. 1455 76

Parathyroid hormone-related peptide (PTHrP) induces pathological bone resorption in an endocrine manner, resulting in hypercalcemia of malignancy. However, the histopathological aspect of the action of PTHrP secreted by tumor cells on bone resorption has not well been documented. Therefore, we studied cell-cell interactions between bone cells, stromal cells, and PTHrP-secreting tumor cells (EC-GI-10) morphologically. Tumor cells injected subcutaneously into the parietal region formed a tumor mass, invading the bone marrow. The tumor mass was surrounded by a membrane structure consisting of stromal cells. These stromal cells were positive for alkaline phosphatase (ALPase). Tartrate-resistant acid phosphatase (TRAPase)-positive osteoclasts were localized close to the ALPase-positive cells, and numerous osteoclasts were observed on the neighboring bone surfaces. PTHrP, vascular endothelial growth factor (VEGF), and matrix metalloproteinase (MMP)-9 were detected in the tumor cells. Using RT-PCR, expression of interleukin (IL)-1Alpha, IL-1Beta, and PTHrP, which are strong bone resorption factors, was detected in the tumor cells. Some ALPase-positive cells localizing on the neighboring bone surfaces and endothelial cells revealed PTH/PTHrP receptor immunoreactivity. Ultrastructurally, numerous blood vessels were observed between the tumor nests and the stromal cells. The nests were surrounded by a basement membrane, but it was discontinuous, therefore permitting direct contact between the tumor cells and the stromal cells. These results indicate that PTHrP secreted by tumor cells appears to stimulate osteoclast differentiation and bone resorption in a paracrine manner through PTH/PTHrP receptor-immunopositive cells. IL-1Alpha, IL-1Beta, VEGF, and MMP-9 may also be involved in facilitating osteoclast formation and the subsequent bone resorption.
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PMID:Ultrastructural and cytobiological studies on possible interactions between PTHrP-secreting tumor cells, stromal cells, and bone cells. 1458 91

The effect of long-term valproate (VPA) treatment on bone mineral density (BMD) in adult epileptic patients is not clearly known, although several studies have been done in children. In adult epileptic patients (n = 50; 24 men, 26 women) treated with VPA, the bone mineral density at lumbar level (L1-L4) and neck, trochanter, and intertrochanter regions of left femur was studied by dual energy X-ray absorptiometry (DXA) at the beginning of the study and after 6 months, with the specific aim to evaluate the effect of long-term valproate monoteraphy on bone mineral density. Routine biochemical parameters were also evaluated. Sixty healthy control subjects were evaluated. Control subjects were similar to patient group with respect to age, race (all White), geographic area, and socioeconomic status. Lumbar and femural BMD values were significantly lower in patient group than control group (0.814 +/- 0.157 g/cm(2) versus 0.894 +/- 0.102 g/cm(2), P = 0.003) and (0.824 +/- 0.144 g/cm(2) versus 0.906 +/- 0.104 g/cm(2), P = 0.001), respectively. Osteopenia were detected in 13 of 60 control subjects (22%) and the others had no osteoporosis. In epileptic group, osteoporosis and osteopenia were detected in 8 subjects (16%), and in 26 subjects (52%), respectively. In epileptic group 16 subjects were normal (32%) at the lumbar regions, and 7 had osteoporosis (14%), 28 had osteopenia (56%), and 15 were normal (30%) at the femoral region. In the second measurements of the patients on valproate treatment, after 6 months, all of the DXA BMD values had worsened compared with the first measurements (P = 0.001 for lumbar BMD values and P = 0.004 for femural BMD values). In the patient group, a significant inverse correlation was observed between duration of valproate therapy and all DXA BMD values in the first and second measurements. Parathyroid hormone, alkaline phosphatase, and phosphor levels of patients were significantly higher than those of control group (52 +/- 11 pg/ml versus 46 +/- 13 pg/ml, P = 0.013), (113 +/- 32 U/l versus 95 +/- 36 U/l, P = 0.006), and (4.50 +/- 0.5 mg/dl versus 4.0 +/- 0.7 mg/dl, P = 0.0001), respectively. However, all of the parameters were within the normal reference ranges. It has been concluded that long-term (more than one year) valproate treatment induces a decrease in bone mineral density in epileptic adults. However, the multivariate analysis did show no association between BMD changes and parathyroid hormone, alkaline phosphatase or phosphorus levels.
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PMID:The effect of valproate on bone mineral density in adult epileptic patients. 1508 34

Observational studies suggest that statin use may be associated with lower incidence of fracture. However, there are conflicting data for their effects on bone remodeling parameters and bone mineral density (BMD). In the present study, we aimed to investigate the effects of simvastatin on bone metabolism and BMD in subjects with hypercholesterolemia (>240 mg/dl). For this purpose, 32 postmenopausal osteopenic subjects who were given simvastatin treatment (20 mg/day) and not on osteoporosis treatment were included in the study. During the 1-year follow-up period, the total cholesterol level decreased from 262.1+/-30.9 to 202.2+/-30.1 mg/dl (p<0.0001). At a period as early as the 3rd month, levels of the anabolic markers, e.g., bone-specific alkaline phosphatase (BSAP) and osteocalcin (OCL), were found to be significantly increased (from 120.8+/-56.6 to 149.5+/-57.6 IU/l, p=0.008, and from 20.8+/-12.6 to 34.7+/-18.4 microg/l, p=0.015, respectively) while no significant change was observed in the resorptive marker of serum N-telopeptide of type I collagen (CTX). At the 6th and 12th month, BSAP and OCL were both found to be decreased below the pretreatment values. While a significant reduction was found in BSAP levels (from 120.8+/-56.6 to 55.9+/-18.8 IU/l, p<0.001), no significant change was observed in CTX levels after the 6-month treatment period. Parathyroid hormone showed a gradual profound increase during the follow-up period (from 62.7+/-41.5 to 108.4+/-51.7 pg/ml, p<0.001). No significant change was found in BMD levels at the spine, femoral neck, Ward's triangle, and trochanter at the end of the 1-year follow-up period. In conclusion, simvastatin treatment showed a short-lasting anabolic effect on bone metabolism. However, this effect was lost by prolongation of therapy. The decrease in both anabolic and resorptive markers at the 6th and 12th month suggests that simvastatin affects bone metabolism mostly in favor of inhibition of the bone turnover in a long-term observation period although this inhibitory effect was not reflected in BMD.
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PMID:Effects of simvastatin on bone mineral density and remodeling parameters in postmenopausal osteopenic subjects: 1-year follow-up study. 1574 22

The management of hyperphosphatemia is essential to treat secondary hyperparathyroidism and to prevent ectopic calcification. Sevelamer hydrochloride (sevelamer), a new phosphate binder that contains neither aluminum nor calcium, which could be theoretically beneficial for the management of hyperphosphatemia in dialysis patients with secondary hyperparathyroidism who are receiving intravenous vitamin D metabolites (maxacalcitol or calcitriol). To reduce calcium loads, a dialysate calcium concentration of 2.5 mEq/L is recommended by Kidney Disease Outcome Quality Initiative (K/DOQI) guidelines. In Japan, a dialysate calcium concentration of 3.0 mEq/L prevails. We investigated the influence of dialysate calcium on the therapeutic effect of sevelamer in 40 hemodialysis patients who are under treatment of intravenous vitamin D metabolites for secondary hyperparathyroidism (VD(+)) and compared the results with those of 41 patients who had not received vitamin D metabolites (VD(-)). Serum phosphorus and calcium-phosphorus products showed no significant change by sevelamer in either the VD(+) subgroup of patients receiving hemodialysis with dialysate calcium of 2.5 mEq/L (DCa2.5) or those receiving hemodialysis with dialysate calcium of 3.0 mEq/L (DCa3.0), while serum phosphorus and calcium-phosphorus products decreased in both the VD(-) subgroups. Serum calcium decreased in the DCa2.5 subgroup and did not change in the DCa3.0 subgroup in both the VD(+) and the VD(-) subjects. Parathyroid hormone and alkaline phosphatase increased in the DCa2.5 subgroup and did not change in the Ca 3.0 subgroup in the VD(+) subjects. Serum calcium decreased in both subgroups in the VD(-) subjects. Parathyroid hormone obtained after sevelamer administration in the VD(-) group was within the target range of the K/DOQI guidelines. In conclusion, the concomitant use of sevelamer as a phosphate binder and the dialysate of calcium concentration of 2.5 mEq/L have possibilities for worsening secondary hyperparathyroidism in patients receiving intravenous vitamin D.
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PMID:The influence of dialysate calcium on the therapeutic effects of sevelamer hydrochloride in hemodialysis patients with secondary hyperparathyroidism under treatment of intravenous vitamin d metabolites. 1582 1

Parathyroid hormone (PTH) exerts both catabolic and anabolic actions on bone. Studies on the skeletal effects of PTH have seldom considered the effects of gender. Our study was designed to determine whether the response of mouse bone to PTH differed according to sex. As a first step, we analyzed gender differences with respect to bone mass and structural properties of 4 month old PTH treated (80 microg/kg per day for 2 weeks) male and female CD-1 mice. PTH significantly increased fat free weight/body weight, periosteal bone formation rate, mineral apposition rate, and endosteal single labeling surface, while significantly decreasing medullary area in male mice compared with vehicle treated controls, but induced no significant changes in female mice. We then analyzed the gender differences in bone marrow stromal cells (BMSC) isolated from 4 month old male and female CD-1 mice following treatment with PTH (80 microg/kg per day for 2 weeks). PTH significantly increased the osteogenic colony number and the alkaline phosphatase (ALP) activity (ALP/cell) by day 14 in cultures of BMSCs from male and female mice. PTH also increased the mRNA level of receptor activator of nuclear factor kappaB ligand in the bone tissue (marrow removed) of both females and males. However, PTH increased the mRNA levels of IGF-I and IGF-IR only in the bones of male mice. Our results indicate that on balance a 2-weeks course of PTH is anabolic on cortical bone in this mouse strain. These effects are more evident in the male mouse. These differences between male and female mice may reflect the greater response to PTH of IGF-I and IGF-IR gene expression in males enhancing the anabolic effect on cortical bone.
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PMID:Gender differences in the response of CD-1 mouse bone to parathyroid hormone: potential role of IGF-I. 1664 95

Human cathepsin K, a cysteine proteinase of the papain family, has been recognized as a potential drug target for the treatment of osteoporosis. The predominant expression of cathepsin K in osteoclasts has rendered the enzyme into a major target for the development of novel antiresorptive drugs. Now, we report the pharmacological properties of OST-4077 [furan-2-carboxylic acid (1-{1-[4-fluoro-2-(2-oxo-pyrrolidin-1-yl)-phenyl]-3-oxo-piperidin-4-ylcarbamoyl}-cyclohexyl)-amide] as a novel selective cathepsin K inhibitor. Human and rat cathepsin K were inhibited in vitro by OST-4077 with the IC50 values of 11 and 427 nM, respectively. OST-4077 suppressed bone resorption induced by rabbit osteoclasts (IC50, 37 nM) but did not affect bone mineralization or cellular alkaline phosphatase activity in MC3T3-E1 cells. Parathyroid hormone-induced bone resorption was inhibited in a dose-dependent manner in thyroparathyroidectomized rats gavaged with a single dose of OST-4077 (ED50, 69 mg/kg). When given orally twice daily for 4 weeks to 3-month-old ovariectomized (OVX) rats, OST-4077 dose-dependently prevented bone loss, as monitored by bone densitometry, ash content, and urinary excretion of deoxypyridinoline. No change in serum osteocalcin in the OVX rats by OST-4077 suggested that bone formation might not be affected by the agent. In summary, OST-4077 selectively inhibited bone resorbing activities of osteoclasts and prevented bone loss induced by estrogen deficiency but did not affect bone formation. OST-4077, an orally active selective human cathepsin K inhibitor, may have the therapeutic potential for the treatment of diseases characterized by excessive bone loss including osteoporosis.
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PMID:An orally active cathepsin K inhibitor, furan-2-carboxylic acid, 1-{1-[4-fluoro-2-(2-oxo-pyrrolidin-1-yl)-phenyl]-3-oxo-piperidin-4-ylcarbamoyl}-cyclohexyl)-amide (OST-4077), inhibits osteoclast activity in vitro and bone loss in ovariectomized rats. 1669 68

Increasing osteoblast activity in an anabolic fashion may offer an ideal therapeutic treatment for various orthopedic complications including osteoporosis. The purpose of this study was to evaluate the effect of mevinolin, a clinical statin drug, on osteoblast function (MG 63 Cell Line) and compare its mode of action with the conventionally utilized parathyroid hormone (PTH). MG63 cells were treated with different concentrations (control, low (100 nM), medium (1 uM), and high (10 uM)) of mevinolin or Parathyroid hormone. The cells were incubated for 24, 48, and 72 hours at 37 degrees C in a 95% air and 5% CO2 environmental chamber. Data obtained in this study revealed that: (I) there were significant decreases in cell number after 24 hours upon the exposure of medium and high doses of mevinolin, (II) cell numbers rebounded back toward control after 48 hours and were similar in number at 72 hours, and (III) there were no significant changes in calcium or alkaline phosphatase activity were observed throughout the study. Morphologically, the cells treated with various doses of Mevinolin expressed similar structural changes to those observed using PTH. These changes included pleomorphic characteristics and an occasional hyperchromatic pattern during the entire duration of the study (72 Hours). Other structural features observed were spindle shapes, cluster arrangements and multinucleation. The majority of cells had multiple nucleoli in all treated groups compared to controls. The overall conclusion of this investigation demonstrated that the concentrations used (100 nM and 10 microM) did not appear to affect the mitotic activities of immature phenotypic MG-63 cells. In addition, the concentrations of mevinolin used did not trigger the differentiation process of the cells throughout the experimental phases. This observation led us to suggest that the reason for such an outcome could be attributed to the lack of a response in calcium production or alkaline phosphatase activity (stimulator to differentiation and mineralization process).
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PMID:Comparison between mevinolin and PTH action on MG63 osteoblast-like cells. 1681 19

Benefits of dialysate with greater calcium (Ca) concentration are reported in nocturnal hemodialysis (NHD) to prevent Ca depletion and subsequent hyperparathyroidism. Studies with patients dialyzing against 1.25 mmol/L Ca baths demonstrate increases in alkaline phosphatase (ALP) and parathyroid hormone (PTH) and increasing dialysate Ca subsequently corrects this problem. However, whether 1.5 or 1.75 mmol/L dialysate Ca is most appropriate for NHD is yet to be determined, and differences in the effect on mineral metabolism of daily vs. alternate daily NHD have also not been well defined. We retrospectively analyzed mineral metabolism in 48 patients, from 2 institutions (30 at Monash and 18 at Geelong), undergoing home NHD (8 hr/night, 3.5-6 nights/week) for a minimum of 6 months. Thirty-seven patients were dialyzed against 1.5 mmol/L Ca bath and 11 patients against 1.75 mmol/L. We divided patients into 4 groups, based on dialysate Ca and also on the hours per week of dialysis, <40 (1.5 mmol/L, n=29 and 1.75 mmol/L, n=8) or > or =40 (n=4 and 7). We compared predialysis and postdialysis serum markers, time-averaged over a 6-month period, and the administration of calcitriol and Ca-based phosphate binders between 1.5 and 1.75 mmol/L Ca dialysate groups. Baseline characteristics between all groups were similar, with a slightly longer, but nonsignificant, duration of NHD in both 1.75 mmol/L dialysate groups compared with 1.5 mmol/L. The mean predialysis Ca, phosphate, and Ca x P were similar between the 1.5 and 1.75 mmol/L groups, regardless of NHD hr/week. Postdialysis Ca was significantly greater, with 1.75 vs. 1.5 mmol/L in those dialyzing <40 hr/week (2.64+/-0.19 vs. 2.50+/-0.12 mmol/L, p=0.046), but postdialysis Ca x P were similar (2.25+/-0.44 vs. 2.16+/-0.29 mmol(2)/L(2), p=0.60). Parathyroid hormone was also lower with 1.75 vs. 1.5 mmol/L baths in the <40 hr/week groups (31.99+/-26.99 vs. 14.47+/-16.36 pmol/L, p=0.03), although this difference was not seen in those undertaking NHD > or =40 hr/week. Hemoglobin, ALP, and albumin were all similar between groups. There was also no difference in vitamin D requirement when using 1.75 mmol/L compared with the 1.5 mmol/L dialysate. Multivariate analysis to determine independent predictors of postdialysis serum Ca showed a statistically significant positive association with predialysis Ca, dialysate Ca, and total NHD hr/week. An elevated dialysate Ca concentration is required in NHD to prevent osteopenia but differences in serum markers of mineral metabolism between 1.5 and 1.75 mmol/L Ca dialysate in NHD in our study were few. This was similar for patients undertaking NHD <40 or > or =40 hr/week, although differences in the frequency of NHD may also be as important as dialysate Ca with regard to serum Ca levels. With concerns that prolonged higher Ca levels contribute to increased cardiovascular mortality, the optimal Ca dialysate bath is still unknown and further studies addressing bone metabolism with larger NHD numbers are required.
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PMID:Comparison between different dialysate calcium concentrations in nocturnal hemodialysis. 1740 74

Parathyroid hormone (PTH) and glycogen synthase kinase-3 (GSK-3) inhibitor 603281-31-8, administered once daily increased bone formation in vivo. We investigated the molecular mechanisms of the anabolic responses of PTH and 603281-31-8 in rat osteopenia model. Female 6-month-old rats were ovariectomized (Ovx) and permitted to lose bone for 1 month, followed by treatment with PTH (1-38) at 10 microg/kg/day s.c. or 603281-31-8 at 3 mg/kg/day p.o. for 60 days. Twenty-four hours after the last treatment, RNA from distal femur metaphysis was subjected to gene expression analysis. Differentially expressed genes (P<0.05) were subjected to pathway analysis to delineate relevant bio-processes involved in skeletal biology. Genes involved in morphogenesis, cell growth/differentiation, and apoptosis were significantly altered by Ovx and the treatments. Analysis of morphogenesis genes showed an overrepresentation of genes involved in osteogenesis, chondrogenesis, and adipogenesis. A striking finding was that Ovx decreased several markers of osteogenesis/chondrogenesis and increased markers of adipogenesis/lipid metabolism. Treatment with either PTH or the GSK-3 inhibitor reversed these effects, albeit at different levels. Histological analysis confirmed that osteopenia in Ovx animals was associated with three-fold increase in marrow adiposity. PTH and GSK-3 inhibitor restored bone volume, and reversed or normalized marrow adiposity. Ex vivo studies showed that PTH and GSK-3 inhibitor increased the ratio of colony forming marrow stromal progenitors (CFU-fs) that were alkaline phosphatase positive (putative osteoblasts). Our results suggest that the bone anabolic actions of PTH and GSK-3 inhibitor in vivo involve concerted effects on mesenchymal lineages; osteoblasts, chondrocytes, and adipocytes.
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PMID:Changes in osteoblast, chondrocyte, and adipocyte lineages mediate the bone anabolic actions of PTH and small molecule GSK-3 inhibitor. 1752 Jun 64


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