Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0004153 (atherosclerosis)
 77,401 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have used the cynomolgus macaque as a model for the study of the effects of endogenous and exogenous sex steroid hormones on atherosclerosis and osteoporosis. As in human beings, premenopausal female cynomolgus macaques develop much less extensive coronary artery atherosclerosis than their male counterparts. Furthermore, surgical menopause results in a more atherogenic plasma lipoprotein pattern and an approximate doubling of atherosclerosis extent. Frequent pregnancy, a hyperoestrogenic state, results in an approximate 50% reduction in atherosclerosis extent. Physiological replacement with 17 beta-oestradiol alone or in combination with progesterone prevents the increase in coronary artery atherosclerosis extent associated with ovariectomy. This effect is independent of plasma lipoprotein concentrations and appears to be accounted for, at least in part, by an inhibitory effect of oestrogen replacement therapy on the uptake and degradation of LDL by the artery wall. Also, as in human beings, treatment with certain types of combination oral contraceptives results in marked decreases in plasma HDL-C concentration. Nonetheless, coronary artery atherosclerosis extent is reduced in monkeys by oral contraceptive treatment, and this effect is most pronounced among animals at highest risk due to theoretically adverse plasma lipoprotein profiles. It appears that, as with oestrogen replacement therapy, this effect can be accounted for, at least in part, by an inhibition of the uptake and degradation of low density lipoprotein by the artery wall. The monkey also appears to be a good model for studies of postmenopausal bone loss. As in women, surgical menopause results in significant diminution of bone mineral density and bone mineral content. Also, serum biomarkers of bone turnover (total alkaline phosphatase, acid phosphatase, tartrate-resistant acid phosphatase and osteocalcin) are increased in surgically postmenopausal monkeys, indicating increased bone turnover resulting from the surgical menopause. These increases in bone loss and indices of bone turnover were prevented by physiological oestrogen replacement therapy. Cynomolgus monkeys seem to be exceptionally useful models for studies of the effects of sex steroid hormones on atherosclerosis and osteoporosis, two major public health problems in postmenopausal women.
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PMID:Effects of oestrogens and progestogens on coronary atherosclerosis and osteoporosis of monkeys. 182 26

A highly sensitive, simple and reliable one-step sandwich enzyme immunoassay (EIA) for the gamma-carboxylated form of osteocalcin (Gla-OC) has been developed using a monoclonal antibody. The minimum amount of Gla-OC detected by this EIA was approximately 0.2 ng/ml when a 10 microliter aliquot of the sample was used. The serum Gla-OC level in 30 healthy subjects was 3.6 +/- 2.19 ng/ml (mean +/- SD). A significant increase was seen in patients with chronic renal failure (20.3 +/- 4.60 ng/ml), atherosclerosis (8.3 +/- 4.94 ng/ml) and osteoporosis (10.1 +/- 4.60 ng/ml). The correlation between the values obtained by the sandwich EIA and competitive RIA methods was given by the linear regression equation, y = 2.896 + 0.759 chi, for which the correlation coefficient (r) was 0.815 (n = 58). This newly developed Gla-OC specific EIA may be useful for the diagnosis of metabolic bone disease and ectopic calcification.
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PMID:A one step sandwich enzyme immunoassay for gamma-carboxylated osteocalcin using monoclonal antibodies. 204 Aug 14

Proteins containing the calcium binding amino acid, gamma-carboxyglutamic acid (Gla), are abundant in calcified human atherosclerotic plaque, but are detectable only at trace levels in the normal arterial wall and non-mineralized atherosclerotic lesions. These proteins have been incompletely characterized, and their role in the pathophysiology of atherosclerosis is not known. The present study sought to determine the overall molecular weight distribution of the calcified plaque Gla-protein fraction solubilized by EDTA demineralization and the possible relationship of these proteins to the bone Gla-protein, osteocalcin. Calcified atheromata were demineralized with EDTA (0.5 M, pH 6.9) for 7 days and the dialyzed EDTA extract subjected to procedures which specifically labeled the protein-bound Gla-residues with tritium. The EDTA solubilized Gla-protein fraction (19.5% of the total Gla) was separated by gel filtration high performance liquid chromatography which demonstrated a single broad radiolabeled Gla-protein peak with an approximate molecular weight of 6000 daltons. In addition the EDTA solubilized atherosclerotic Gla-proteins could be distinguished from the bone Gla-protein, osteocalcin (molecular weight = 5700 daltons), by reverse phase HPLC and specific radioimmunoassays for osteocalcin. It is concluded that the Gla-proteins of human calcified atherosclerotic plaque solubilized with EDTA demineralization consist of a heterogeneous 6000 dalton fraction, which is apparently unrelated to the bone Gla-protein, osteocalcin.
Atherosclerosis 1986 Feb
PMID:Carboxyglutamic acid (Gla) containing proteins of human calcified atherosclerotic plaque solubilized by EDTA. Molecular weight distribution and relationship to osteocalcin. 308 31

Calcium binding proteins containing gamma-carboxyglutamic acid (Gla) have previously been demonstrated to occur in calcified atherosclerotic plaque and calcified cardiac valves. Experiments were carried out to determine if one of the Gla-containing proteins in human cardiovascular calcifications is the vitamin K-dependent bone protein, osteocalcin. A radio-immunoassay for human osteocalcin was employed, and EDTA extractions of calcified atheromata, and aortic valves as well as relevant noncalcified material were analyzed. Tissue calcium levels were also determined, as were Gla levels as a measure of total vitamin K-dependent protein content. Osteocalcin was present at low levels in all calcified cardiovascular tissues (4.5-175.7 ng osteocalcin/mg protein) with trace levels or nondetectable amounts present in noncalcified tissue. Osteocalcin accounted for a small proportion of the total protein-bound Gla (0.01-0.05%). The relationship of osteocalcin to the other Gla-containing proteins of atherosclerotic plaque including atherocalcin, the principal extractable Gla-containing protein of calcified plaque, is discussed.
Atherosclerosis 1983 Jan
PMID:The identification of the vitamin K-dependent bone protein osteocalcin as one of the gamma-carboxyglutamic acid containing proteins present in calcified atherosclerotic plaque and mineralized heart valves. 660 88

Protein-bound gamma-carboxyglutamate (Gla) has been demonstrated in calcified atherosclerotic plaques. Vitamin K is required for the formation of Gla-residues. As the biological activity of Gla-proteins appears to be strictly dependent on the presence of the Gla-residues, vitamin K status may be an important factor in the development and progression of atherosclerotic calcifications. We studied the association of vitamin K status, as assessed by nutritional vitamin K intake and the measurements of two circulating immunoreactive osteocalcin (irOC) fractions, with aortic atherosclerosis in a population-based study of 113 postmenopausal women. Women with calcified lesions (n = 34) had a 42.9 micrograms lower mean age-adjusted dietary vitamin K intake/day (95% C.I. -6.6 to 92.5) than those without calcifications (n = 79). Atherosclerotic women had higher irOC levels with a low affinity for hydroxyapatite (irOCfree): age-adjusted difference of 0.32 ng/ml (95% C.I. 0.03 to 0.61). In addition, the high affinity irOC levels expressed as a percentage (hydroxyapatite binding capacity, HBC) were 5.12% (95% C.I. 1.32 to 8.92) lower in women with calcifications. Our study indicates that women with aortic atherosclerosis have an impaired vitamin K status as reflected by a lower nutritional vitamin K intake, an increased irOCfree level and a reduced HBC level. An impaired vitamin K status in subjects with atherosclerosis is compatible with the view that vitamin K or Gla-containing proteins are involved in the development of calcification of the vessel wall.
Atherosclerosis 1995 Jul
PMID:Vitamin K intake and osteocalcin levels in women with and without aortic atherosclerosis: a population-based study. 748 26

Previous studies in our laboratory demonstrated messenger RNA for bone morphogenetic protein-2a in human calcified plaque, suggesting that arterial calcification is a regulated process, similar to osteogenesis. To further test this hypothesis, we have isolated and cloned a subpopulation of cells from bovine aortic media that show osteoblastic potential. These novel cells are primarily distinguished from smooth muscle cells by expression of a surface marker preliminarily identified as a modified form of the ganglioside sialyl-lactosylceramide (GM3). Osteoblastic potential was indicated by high levels of alkaline phosphatase and collagen I, expression of osteopontin and osteonectin (SPARC), and production of bone-specific osteocalcin and hydroxyapatite. Cultures of these cells were stimulated to form increased numbers of calcium-mineral-producing nodules by the oxysterol 25-hydroxycholesterol as well as by transforming growth factor-beta 1, both known to be present in atherosclerotic lesions. The stimulation of calcifying vascular cells in the artery wall by these two factors suggests a possible mechanism for the colocalization of calcification with atherosclerosis in vivo.
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PMID:TGF-beta 1 and 25-hydroxycholesterol stimulate osteoblast-like vascular cells to calcify. 818 41

Patients with primary hyperparathyroidism have increased bone turnover, but it is less well documented how brief periods of excess parathyroid hormone (PTH) (endogenous or exogenous) affect bone metabolism. In the present double blind study, we examined the effect of either ethylenediaminetetraacetatic acid (EDTA) or placebo on serum levels of PTH and biochemical markers of bone turnover in 15 women and 39 men (aged 41 to 81 years) suffering intermittent claudication due to atherosclerosis. Disodium EDTA was administered as 20 repeated infusions of 3 grams during a period of 5-9 weeks. Serum calcium and serum phosphate decreased following treatment (p < 0.001) and remained unchanged in the placebo group. However, the differences between the groups were insignificant (ANOVA p = 0.13 and p < 0.10, respectively). PTH increased 2 1/2 fold following EDTA treatment (p < 0.001, ANOVA). The change in serum PTH was inversely correlated with the change in serum calcium (r = -0.53, p < 0.01). In the EDTA group, urinary hydroxyproline/creatinine and calcium/creatinine increased after treatment (ANOVA p < 0.001 and p < 0.05, respectively). Serum bone alkaline phosphatase decreased significantly in the EDTA group immediately after treatment (p < 0.001, ANOVA) and returned to baseline level at three months while only an insignificant decrease in serum osteocalcin was seen following treatment. We conclude that EDTA treatment increases endogenous PTH secretion considerably and leads to increased bone resorption. However, no changes in osteoblastic markers indicating increased activation of bone remodeling could be demonstrated. Our findings support that chelation therapy with EDTA is accompanied by bone loss.
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PMID:Effects of intravenous EDTA treatment on serum parathyroid hormone (1-84) and biochemical markers of bone turnover. 829 6

The optimal surgical procedure for severe renal secondary hyperparathyroidism (sHPT) is still a point of controversy. Total parathyroidectomy (PTX) without auto-transplantation was abandoned for fear of an adynamic bone condition; however, in the case of autotransplantation recurrent sHPT is frequent and promotes atherosclerosis. We studied 11 hemodialysis patients (age 59+/-12 years) on dialysis for 18 (12-30) years in whom total PTX was performed due to severe sHPT (group I; intact PTH: 1,240+/-230 pg/ml), and 5 patients (age 55+/-10 years) without renal insufficiency who inadvertently received total PTX during thyroid surgery (group II). After total PTX (group I, 26+/-18 [9-59] months; group II, 252+/-188 [22 480] months) both groups showed no measurable intact PTH levels. Calcium homeostasis was maintained by oral substitution with calcium (group I, calcium dialysate of 2.0 mmol/l), vitamin D and calcitriol (serum parameters in groups I and II: calcium 2.4 and 2.2 mmol/l; phosphate 1.8 and 1.1 mmol/l; 25(OH)-vitamin D(3) 21 and 34 ng/ml; 1,25(OH)(2)-vitamin D(3) 32 and 41 pg/ml, respectively). In group I, after total PTX there was a rapid and sustained improvement in bone pain with markedly enhanced physical activity and endurance. High turnover osteopathy markedly improved as indicated by declining levels of native osteocalcin (90+/-17 vs. 26+/-18 ng/ml), bone alkaline phosphatase (74+/-12 vs. 12+/-6 ng/ml), and carboxyterminal cross-linked telopeptide of type-I collagen (65+/-16 vs. 40+/-21 ng/ml) but increasing levels of carboxyterminal propeptide of type-I procollagen (120+/-36 vs. 148+/-41 ng/ml). Recalcification of bone was excellent as demonstrated by X-ray and confirmed by bone histology. Itching extravascular calcific deposits and calcifications of blood vessel and cardiac valves immediately stopped after total PTX. Moreover, 6 sHPT patients suffered from severe atherosclerotic lesions such as thoracic aortic aneurysm (n = 3) or abdominal aortic aneurysm (n = 3) which showed size progression before but not after total PTX when annually controlled by ultrasonography. In group II, even long after total PTX, there was no clinical, radiological, histological or biochemical evidence for low turnover osteopathy. In conclusion, our data indicate that substitution with vitamin D(3) metabolites and calcium can prevent deleterious bone effects of hypoparathyroidism in hemodialysis patients and in patients with normal kidney function and may compensate for the missing PTH action. Over this, a better survival rate is expected as a consequence of the beneficial effect of total PTX on the progression of atherosclerotic lesions. We suggest reconsideration of total PTX without autotransplantation in dialysis patients with severe sHPT who are not eligible for renal transplantation.
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PMID:Long-term results of total parathyroidectomy without autotransplantation in patients with and without renal failure. 1043 1

Advanced atherosclerosis is often associated with dystrophic calcification, which may contribute to plaque rupture and thrombosis. In this work, the localization and association of the noncollagenous bone matrix proteins osteonectin, osteopontin, and osteocalcin with calcification, lipoproteins, thrombus/hemorrhage (T/H), and matrix metalloproteinases (MMPs) in human carotid arteries from endarterectomy samples have been determined. According to the recent American Heart Association classification, 6 of the advanced lesions studied were type V (fibroatheroma) and 16 type VI (complicated). Osteonectin, osteocalcin, and osteopontin were identified by monoclonal antibodies IIIA(3)A(8), G12, and MPIIIB10(1) and antiserum LF-123. Apolipoprotein (apo) AI, B, and E; lipoprotein(a); fibrinogen; fibrin; fragment D/D-dimer; MMP-2 (gelatinase A); and MMP-3 (stromelysin-1) were identified with previously characterized antibodies. Calcium phosphate deposits (von Kossa's stain) were present in 82% of samples (3 type V and 15 type VI). Osteonectin was localized in endothelial cells, SMCs, and macrophages and was associated with calcium deposits in 33% of type V and 88% of type VI lesions. Osteopontin was distributed similarly to osteonectin and was associated with calcium deposits in 50% of type V and 94% of type VI lesions. Osteocalcin was localized in large calcified areas only (in 17% of type V and 38% of type VI lesions). ApoB colocalized with cholesterol crystals and calcium deposits. Lipoprotein(a) was localized in the intima, subintima, and plaque shoulder. Fibrin (T/H) colocalized with bone matrix proteins in 33% of type V and 69% of type VI lesions. MMP-3 was cytoplasmic in most cells and colocalized with calcium and fibrin deposits. MMP-2 was less often associated with calcification. The results of this study show that osteonectin, osteopontin, and osteocalcin colocalized with calcium deposits with apoB, fibrin, and MMP-3 in advanced, symptomatic carotid lesions. These data suggest that the occurrence of T/H might contribute to dystrophic arterial calcification in the progression and complications of atherosclerosis.
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PMID:Noncollagenous bone matrix proteins, calcification, and thrombosis in carotid artery atherosclerosis. 1044 63

Vascular calcification is a common finding in atherosclerosis and a serious problem in diabetic and uremic patients. Because of the correlation of hyperphosphatemia and vascular calcification, the ability of extracellular inorganic phosphate levels to regulate human aortic smooth muscle cell (HSMC) culture mineralization in vitro was examined. HSMCs cultured in media containing normal physiological levels of inorganic phosphate (1.4 mmol/L) did not mineralize. In contrast, HSMCs cultured in media containing phosphate levels comparable to those seen in hyperphosphatemic individuals (>1.4 mmol/L) showed dose-dependent increases in mineral deposition. Mechanistic studies revealed that elevated phosphate treatment of HSMCs also enhanced the expression of the osteoblastic differentiation markers osteocalcin and Cbfa-1. The effects of elevated phosphate on HSMCs were mediated by a sodium-dependent phosphate cotransporter (NPC), as indicated by the ability of the specific NPC inhibitor phosphonoformic acid, to dose dependently inhibit phosphate-induced calcium deposition as well as osteocalcin and Cbfa-1 gene expression. With the use of polymerase chain reaction and Northern blot analyses, the NPC in HSMCs was identified as Pit-1 (Glvr-1), a member of the novel type III NPCs. These data suggest that elevated phosphate may directly stimulate HSMCs to undergo phenotypic changes that predispose to calcification and offer a novel explanation of the phenomenon of vascular calcification under hyperphosphatemic conditions. The full text of this article is available at http://www.circresaha.org.
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PMID:Phosphate regulation of vascular smooth muscle cell calcification. 1100 70


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