Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0011849 (diabetes)
 277,896 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Although numerous clinical studies have demonstrated the beneficial effect of preventing postmenopausal bone loss in elder women by long-term estrogen administration, effects of estrogen at the cellular level still remain unclear. Efforts to determine the precise role of bone cells in estrogen-mediated pathways are often hampered by the lack of suitable cell culture models. Presuming that sex steroids have a direct, stimulating effect on bone cells in vitro, we investigated the influence of 17beta-estradiol, testosterone and 1,25(OH)2D, on cell proliferation and differentiation using four established human osteosarcoma (HOS) cell lines of different gender of the donors (male origin: MG 63, HOS 58; female origin: SaOS 2, TE 85). These cell lines are believed to represent different stages of osteogenic maturation. Thus, the aim of this study was to clarify if possible responses to sex steroids are related to gender or osteogenic commitment of the individual cell culture. HOS cells were cultured in six-well plates and underwent hormone treatment (1 nM and 10 nM 17beta-estradiol. 0.1 nM and I nM testosterone and 1 microM 1,25(OH)2D3) for 48 h hours. Cell proliferation was determined by measuring total cell numbers. Cell function was studied by measuring alkaline phosphatase activity and secreted osteocalcin. In this study, estrogen significantly increased proliferation of both one male (MG 63) and one female (SaOS 2) cell line, but decreased proliferation of the female HOS TE 85 cell line significantly. Testosterone treatment had a positive effect on proliferation of only one female cell line (SaOS 2). A significant increase of alkaline phosphatase activity in SaOS 2 and HOS 58 cells and of osteocalcin levels in SaOS 2 cells was detected following estrogen treatment. Administration of 1.25(OH)2D3 was followed by an increased cell proliferation in HOS 58, MG 63 and SaOS 2. Significant gender-related differences could not be demonstrated. In conclusion, response to hormonal treatment with sex steroids is not related to the gender of the osteosarcoma cell line, but rather depends on its osteoblastic commitment.
Exp Clin Endocrinol Diabetes 2000
PMID:Sex steroids and bone metabolism: comparison of in vitro effects of 17beta-estradiol and testosterone on human osteosarcoma cell lines of various gender and differentiation. 1102 55

In the aorta, diabetes activates an osteogenic program that includes expression of bone morphogenetic protein-2 (BMP2) and the osteoblast homeoprotein Msx2. To evaluate BMP2-Msx2 signaling in vascular calcification, we studied primary aortic myofibroblasts. These cells express vascular smooth muscle cell (VSMC) markers, respond to BMP2 by up-regulating Msx2, and undergo osteogenic differentiation with BMP2 treatment or transduction with a virus encoding Msx2. The osteoblast factor osterix (Osx) is up-regulated 10-fold by Msx2, but Runx2 mRNA is unchanged; the early osteoblast marker alkaline phosphatase increases 50-fold with mineralized nodule formation enhanced 30-fold. Adipocyte markers are concomitantly suppressed. To better understand Msx2 actions on osteogenesis versus adipogenesis, mechanistic studies were extended to C3H10T1/2 mesenchymal cells. Msx2 enhances osteogenic differentiation in synergy with BMP2. Osteogenic actions depend upon intrinsic Msx2 DNA binding; the gain-of-function variant Msx2(P148H) directs enhanced mineralization, whereas the binding-deficient variant Msx2(T147A) is inactive. Adipogenesis (lipid accumulation, Pparg expression) is inhibited by Msx2. By contrast, suppression of adipogenesis does not require Msx2 DNA binding; inhibition occurs in part via protein-protein interactions with C/EBPalpha that control Pparg transcription. Thus, Msx2 regulates osteogenic versus adipogenic differentiation of aortic myofibroblasts. Myofibroblasts capable of both fates can be diverted to the osteogenic lineage by BMP2-Msx2 signaling and contribute to vascular calcification.
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PMID:MSX2 promotes osteogenesis and suppresses adipogenic differentiation of multipotent mesenchymal progenitors. 1292 29

Cardiovascular calcification is a common consequence of diabetes. High fat diets induce diabetes and arterial calcification in male low density lipoprotein receptor (LDLR) -/- mice; calcification occurs via Msx2 signaling that promotes the osteogenic differentiation of arterial myofibroblasts. We studied regulation of arterial osteogenesis by human parathyroid hormone (PTH) (1-34) (also called teriparatide) in LDLR -/- mice fed diabetogenic diets for 4 weeks. LDLR -/- mice were treated with vehicle or 0.4 mg/kg of PTH(1-34) subcutaneously five times/week. Gene expression was determined from single aortas and hind limb RNA by fluorescence reverse transcription-PCR. Valve calcification was determined by histological staining of cardiac sections using image analysis to quantify valve leaflet mineralization. PTH(1-34) increased bone mineral content (by dual energy x-ray absorptiometry) in LDLR -/- mice, with induction of osseous osteopontin (OPN) expression and serum OPN levels (>150 nM); PTH(1-34) did not significantly change serum glucose, lipids, body weight, or fat mass. PTH(1-34) suppressed aortic OPN and Msx2 expression >50% and decreased cardiac valve calcification 80% (8.3 +/- 1.5% versus 1.4 +/- 0.5%; p < 0.001). Of the known circulating regulators of vascular calcification (OPN, osteoprotegerin, and leptin), PTH(1-34) regulated only serum OPN. We therefore studied actions of PTH(1-34) and OPN in vitro on cells induced to mineralize with Msx2. OPN (5-50 nM) reversed Msx2-induced mineralization. PTH(1-34) inhibited mineralization by 40% and down-regulated Msx2 in aortic myofibroblasts. PTH(1-34) inhibits vascular calcification and aortic osteogenic differentiation via direct actions and potentially via circulating OPN. PTH(1-34) exerts beneficial actions at early stages of macrovascular disease responses to diabetes and dyslipidemia.
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PMID:Teriparatide (human parathyroid hormone (1-34)) inhibits osteogenic vascular calcification in diabetic low density lipoprotein receptor-deficient mice. 1450 75

In vivo electron paramagnetic resonance (EPR) with nitroxyl spin probes has been used for the evaluation of in vivo free radical reactions and redox status in living animals. The aim of this study was to clarify the location of free radical reactions induced by hyperglycemia in osteogenic disorder shionogi (ODS) rats using in vivo EPR spectroscopy. Diabetes was induced by intravenous injection of streptozotocin (STZ). The amount of ascorbic acid (AsA) in ODS rats was controlled by feeding AsA-containing water. Fourteen days after STZ injection, blood glucose and plasma malondialdehyde levels in STZ-treated rats significantly increased compared with untreated rats. Signal decay rates of intravenously injected 3-carbamoyl-2,2,5,5-tetramethyl-1-pyrrolidinyloxy (carbamoyl-PROXYL) (less membrane permeable) and 3-carboxy-PROXYL (membrane impermeable) were enhanced in STZ-treated rats in agreement with the previous reports. The decay rate of 3-acetoxymethoxy-PROXYL (membrane permeable) was significantly enhanced by STZ treatment in AsA-depleted rats, and this enhancement was partially restored to the control value by xanthine oxidase inhibitor, although the rate in AsA-supplemented rats was not changed by STZ treatment. These results suggested that the enhancement of signal decay occurred mainly in the intravascular region in STZ-induced diabetic rats and that AsA depletion induced the enhancement of intracellular signal decay through xanthine oxidase, although it is not clear whether the enhancement of signal decay is the cause or the effect of STZ-induced diabetes.
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PMID:In vivo measurement of redox status in streptozotocin-induced diabetic rat using targeted nitroxyl probes. 1513 Feb 87

Vascular calcification, long thought to result from passive degeneration, involves a complex, regulated process of biomineralization resembling osteogenesis. Evidence indicates that proteins controlling bone mineralization are also involved in the regulation of vascular calcification. Artery wall cells grown in culture are induced to become osteogenic by inflammatory and atherogenic stimuli. Furthermore, osteoclast-like cells are found in calcified atherosclerotic plaques, and active resorption of ectopic vascular calcification has been demonstrated. In general, soft tissue calcification arises in areas of chronic inflammation, possibly functioning as a barrier limiting the spread of the inflammatory stimulus. Atherosclerotic calcification may be one example of this process, in which oxidized lipids are the inflammatory stimulus. Calcification is widely used as a clinical indicator of atherosclerosis. It progresses nonlinearly with time, following a sigmoid-shaped curve. The relationship between calcification and clinical events likely relates to mechanical instability introduced by calcified plaque at its interface with softer, noncalcified plaque. In general, as calcification proceeds, interface surface area increases initially, but eventually decreases as plaques coalesce. This phenomenon may account for reports of less calcification in unstable plaque. Vascular calcification is exacerbated in certain clinical entities, including diabetes, menopause, and osteoporosis. Mechanisms linking them must be considered in clinical decisions. For example, treatments for osteoporosis may have unanticipated effects on vascular calcification; the converse also applies. Further understanding of processes governing vascular calcification may yield new therapeutic options for vascular disease.
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PMID:Vascular calcification: mechanisms and clinical ramifications. 1547 32

Vascular calcification often occurs with advancing age, atherosclerosis, various metabolic disorders such as diabetes mellitus and end-stage renal disease, or in rare genetic diseases, leading to serious clinical consequences. Such mineralization can occur at various sites (cardiac valves, arterial intima or media, capillaries), involve localized or diffuse widespread calcification, and result from numerous causes that provoke active inflammatory and osteogenic processes or disordered mineral homeostasis. Although valuable research has defined many key factors and cell types involved, surprising new insights continue to arise that deepen our understanding and suggest novel research directions or strategies for clinical intervention in calcific vasculopathies. One emerging area in vascular biology involves the RANKL/RANK/OPG system, molecules of the tumor necrosis factor-related family recently discovered to be critical regulators of immune and skeletal biology. Evidence is accumulating that such signals may be expressed, regulated, and function in vascular physiology and pathology in unique ways to promote endothelial cell survival, angiogenesis, monocyte or endothelial cell recruitment, and smooth muscle cell osteogenesis and calcification. Concerted research efforts are greatly needed to understand these potential roles, clarify whether RANKL (receptor activator of nuclear factor kappaB ligand) promotes and osteoprotegerin (OPG) protects against vascular calcification, define how OPG genetic polymorphisms relate to cardiovascular disease, and learn whether elevated serum OPG levels reflect endothelial dysfunction in patients. Overall, the RANKL/RANK/OPG system may mediate important and complex links between the vascular, skeletal, and immune systems. Thus, these molecules may play a central role in regulating the development of vascular calcification coincident with declines in skeletal mineralization with age, osteoporosis, or disease.
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PMID:Regulation of vascular calcification by osteoclast regulatory factors RANKL and osteoprotegerin. 1556 64

Patients with diabetes have greatly elevated risks of atherosclerotic diseases such as coronary artery disease (CAD) and stroke. Vascular calcification in advanced atherosclerosis is a common feature in diabetic patients. In vitro and in vivo studies suggest that apoptosis and chondro/osteogenic differentiation of vascular wall cells such as smooth muscle cells may play important roles in the progression of vascular calcification. Diabetes may promote vascular calcification through the action of various factors including hyperglycemia, oxidative stress, tumor necrosis factor-alpha, and advanced glycation end products. Detection of coronary calcium by electron-beam computed tomography (EBCT) revealed clinical significance of vascular calcification and this technique may be a useful method to identify diabetic patients with increased risks of cardiovascular disease and stroke.
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PMID:[Significance of vascular calcification in diabetic patients with increased risks of cardiovascular disease and stroke]. 1577 91

Osteoprotegerin (OPG) is a bone-related protein that is also present in the vasculature. Recent data suggest that it may play a special role in arterial disease among patients with diabetes. Diabetic macroangiopathy is characterized by a series of diffuse, non-atherosclerotic alterations that hypothetically increase the vulnerability of the vessel wall to atherogenic processes. One prominent feature of the macroangiopathy is linear media calcifications, which have been found to impose a strong risk of future cardiovascular events in epidemiological studies. The mechanisms behind the development of calcifications are unknown, but may be related to the occurrence of diffuse matrix alterations in the arterial wall in diabetes. Interestingly, we have recently observed that the amounts of OPG are increased in the tunica media in arterial tissue from diabetic patients. OPG has been linked to vascular calcifications in immunohistochemical analysis of atherosclerotic tissue and experimental studies on OPG knockout mice. Thus, it is possible that increased arterial OPG concentrations reflect an osteogenic transformation of the vasculature in patients with diabetes as an aspect of diabetic macroangiopathy. This review will evaluate data about OPG in the vasculature and focus on a possible role of OPG in the arterial wall in diabetes.
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PMID:Osteoprotegerin and diabetic macroangiopathy. 1591 17

Calcification of vascular elastin occurs in patients with arteriosclerosis, renal failure, diabetes, and vascular graft implants. We hypothesized that pathological elastin calcification is related to degenerative and osteogenic mechanisms. To test this hypothesis, the temporal expression of genes and proteins associated with elastin degradation and osteogenesis was examined in the rat subdermal calcification model by quantitative real-time reverse transcription-polymerase chain reaction and specific protein assays. Purified elastin implanted subdermally in juvenile rats exhibited progressive calcification in a time-dependent manner along with fibroblast and macrophage infiltration. Reverse transcription-polymerase chain reaction analysis showed that relative gene expression levels of matrix metalloproteinases (MMP-2 and MMP-9) and transforming growth factor-beta1 were increased in parallel with calcification. Gelatin zymography showed strong MMP activities at early time points, which were associated with high levels of soluble elastin peptides. Gene expression of core binding factor alpha-1, an osteoblast-specific transcription factor, increased in parallel with elastin calcification and attained approximately 9.5-fold higher expression at 21 days compared to 3 days after implantation. Similarly, mRNA levels of the bone markers osteopontin and alkaline phosphatase also increased progressively, but osteocalcin levels remained unchanged. We conclude that degenerative and osteogenic processes may be involved in elastin calcification.
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PMID:Elastin calcification in the rat subdermal model is accompanied by up-regulation of degradative and osteogenic cellular responses. 1643 63

It is well known that diabetes affects bone in human and animal models, and leads to osteopenia and osteoporosis. Bone-mineral density and other biochemical markers of bone turnover are very much affected in people with diabetes. Reduced bone mass, occurring with increased frequency in diabetes mellitus, has been attributed to poor glycemic control, but the pathogenic mechanisms remain unknown. High concentrations of glucose (hyperglycemia) in diabetics leads to this complication. Very few in vitro studies using bone-cell lines have been carried out to address this problem. In this study, we examined the effects of different doses of glucose concentration (5.5, 16.5, and 49.4 mmol/L), alone, with insulin (0.6 microg/mL), or with 17beta-estradiol (E2) (10 nmol/L), on rat bone-marrow stromal cells (BMSCs) in the presence of an osteogenic medium. BMSC proliferation and alkaline phosphatase (ALP) were studied after 3 and 7 d of culture, respectively; the area stained for collagen and mineralized nodules was studied after 28 d of culture. With high concentrations of glucose, BMSC proliferation, ALP activity, the number of nodules formed, and the area stained for collagen were greatly reduced. Insulin treatment alone was able to increase [3H]-thymidine uptake or ALP activity, whereas both insulin and estradiol were able to increase the number of mineralized nodules and the area stained for collagen and mineralization. In conclusion, this study suggests that insulin and estradiol are able to contain the deleterious effect of high concentrations of glucose on BMSC-derived osteoblast proliferation and function.
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PMID:Effects of glucose and its modulation by insulin and estradiol on BMSC differentiation into osteoblastic lineages. 1646 93


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