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Query: UMLS:C0004153 (atherosclerosis)
 77,401 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Although it has long been thought that environmental toxins may play an underlying role in vascular diseases such as atherosclerosis, this concept is not supported by any clear-cut experimental evidence of toxic metabolism by cardiovascular enzymes. In this study, we demonstrate that allylamine, a selective cardiovascular toxin in vivo, is actively metabolized in vitro by a purified vascular enzyme (semicarbazide-sensitive amine oxidase), which has been localized recently to vascular smooth muscle cells. Oxidative deamination of allylamine to a highly toxic aldehyde, acrolein, was blocked through enzyme inhibition by semicarbazide-sensitive amine oxidase suggests that this vascular enzyme's physiological role may include metabolism of exogenous amines.
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PMID:A role for a new vascular enzyme in the metabolism of xenobiotic amines. 210 85

Methylamine can be converted by semicarbazide-sensitive amine oxidase (SSAO) to formaldehyde and hydrogen peroxide, which have been proven to be toxic towards cultured endothelial cells. We investigated whether or not these deaminated products from methylamine can exert potentially hazardous toxic effects in vivo. Long lasting residual radioactivity in different tissues was detected following administration of [14C]-methylamine in the mouse. Approximately 10% of the total administered radioactivity could even be detected 5 days after injection of [14C]-methylamine. Eighty percent of the formation of irreversible adducts can be blocked by a highly selective SSAO inhibitor, (E)-2-(4-fluorophenethyl)-3-fluoroallylamine hydrochloride (MDL-72974A). The residual radioactivity was primarily associated with the insoluble tissue components and the soluble macromolecules. Radioactively labelled macromolecules were fragmented following enzymatic proteolysis. Results suggest that the formaldehyde derived from methylamine interacts with proteins in vivo. In the streptozotocin-induced diabetic mice, both SSAO activity and the formation of residual radioactivity were found to be significantly increased in the kidney. Chronic administration of methylamine enhances blood prorenin level, which strongly suggests that uncontrolled deamination of methylamine may be a risk factor for initiation of endothelial injury, and subsequent genesis of atherosclerosis.
Atherosclerosis 1996 Feb
PMID:Formaldehyde produced endogenously via deamination of methylamine. A potential risk factor for initiation of endothelial injury. 864 60

The mouse is known to be highly resistant to atherosclerosis. However, some inbred mouse strains are vulnerable to atherosclerosis when they are fed a high-cholesterol, high-fat diet. Increased deamination of methylamine (MA) and the subsequent production of formaldehyde has been recently shown to be a potential risk factor of atherosclerosis. In the present study semicarbazide-sensitive amine oxidase (SSAO)-mediated MA turnover in C57BL/6 mouse, a strain very susceptible to atherosclerosis, has been assessed in comparison to a moderate, i.e. BALB/c, and resistant, i.e. CD1, mouse strains. Kidney and aorta SSAO activities were found to be significantly increased in C57BL/6 in comparison to BALB/c and CD1 mice. A significant increase of urinary MA and formaldehyde were detected in C57BL/6. [14C]MA following intravenous injection would be quickly metabolized by SSAO. The labeled formaldehyde product would cross link with proteins. C57BL/6 exhibits significantly higher labeled protein adducts than BALB/c and CD1 in response to [14C]MA. The results indicated that mice vulnerable to atherosclerosis possess an increased SSAO-mediated MA turnover. The increase of production of formaldehyde, possibly other aldehydes, may induce endothelial injury or be chronically involved in protein cross-linking and subsequent angiopathy.
Atherosclerosis 1998 Oct
PMID:Endogenous formaldehyde as a potential factor of vulnerability of atherosclerosis: involvement of semicarbazide-sensitive amine oxidase-mediated methylamine turnover. 986 79

Recent data suggest that elevated serum semicarbazide-sensitive amine oxidase activity (SSAO) may cause endothelial injury. Formation of cytotoxic metabolites (especially formaldehyde) and increased oxidative stress might lead to initiation or progression of atherosclerosis. Effective and selective inhibitors of human SSAO might exert cytoprotective effect on endothelial cells. To compare the inhibitor sensitivity of human serum and vascular tissue SSAO enzyme, the inhibitory effect of semicarbazide and MDL 72974A was investigated. Serum and vascular SSAO activity has been determined using 14C-benzylamine as a substrate. The IC50 values of semicarbazide were estimated to be 5x10(-3) M and 5x10(-4) M for SSAO from human serum and saphenous vein, respectively. MDL 72974A amine oxidase inhibitor was more than thousand times more effective than semicarbazide. The IC50 values were 10(-7) M and 10(-8) M for SSAO from human serum and saphenous vein, respectively. This finding supports the hypothesis that soluble and membrane-bound vascular SSAO enzymes might have similar structure.
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PMID:Inhibitor sensitivity of human serum and vascular semicarbazide-sensitive amine oxidases. 1106 Dec 16

The enzyme of semicarbazide-sensitive amine oxidase (SSAO) activity has been reported to be elevated in blood from diabetic patients. SSAO are widely distributed in plasma membranes of various tissues and blood plasma. SSAO-mediated production of toxic aldehydes has been proposed to be related to pathophysiological conditions. Cytotoxic metabolites by SSAO may cause endothelial injury and subsequently induce atherosclerosis. The precise physiological functions of SSAO could play an important role in the control of energy balance in adipose tissue. It is possible that the increased SSAO activity in diabetes may be a result of up-regulation due to increase of SSAO substrates, such as methylamine or aminoacetone. SSAO could play an important role in the regulation of adipocyte homeostasis. Inhibition of SSAO could be of therapeutic value for treatment of diabetic patient.
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PMID:Diabetes and semicarbazide-sensitive amine oxidase (SSAO) activity: a review. 1648 46

Increased risk of vasospasm, a spontaneous hyperconstriction, is associated with atherosclerosis, cigarette smoking, and hypertension-all conditions involving oxidative stress, lipid peroxidation, and inflammation. To test the role of the lipid peroxidation- and inflammation-derived aldehyde, acrolein, in human vasospasm, we developed an ex vivo model using human coronary artery bypass graft (CABG) blood vessels and a demonstrated acrolein precursor, allylamine. Allylamine induces hypercontraction in isolated rat coronary artery in a semicarbazide-sensitive amine oxidase activity (SSAO) dependent manner. Isolated human CABG blood vessels (internal mammary artery, radial artery, saphenous vein) were used to determine: (1) vessel responses and sensitivity to acrolein, allylamine, and H(2)O(2) exposure (1 microM-1 mM), (2) SSAO dependence of allylamine-induced effects using SSAO inhibitors (semicarbazide, 1 mM; MDL 72274-E, active isomer; MDL 72274-Z, inactive isomer; 100 microM), (3) the vasoactive effects of two other SSAO amine substrates, benzylamine and methylamine, and (4) the contribution of extracellular Ca(2+) to hypercontraction. Acrolein or allylamine but not H(2)O(2), benzylamine, or methylamine stimulated spontaneous and pharmacologically intractable hypercontraction in CABG blood vessels that was similar to clinical vasospasm. Allylamine-induced hypercontraction and blood vessel SSAO activity were abolished by pretreatment with semicarbazide or MDL 72274-E but not by MDL 72274-Z. Allylamine-induced hypercontraction also was significantly attenuated in Ca(2+)-free buffer. In isolated aorta of spontaneously hypertensive rat, allylamine-induced an SSAO-dependent contraction and enhanced norepinephrine sensitivity but not in Sprague-Dawley rat aorta. We conclude that acrolein generation in the blood vessel wall increases human susceptibility to vasospasm, an event that is enhanced in hypertension.
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PMID:Acrolein generation stimulates hypercontraction in isolated human blood vessels. 1709 30

Sclerotic calcification of the aortic valve is a common disease in advanced age. Its pathophysiology is unclear. However, pathobiological similarities to atherosclerosis have been shown in several studies. The current study assesses gene profiling of severe calcified stenotic human aortic valves identifying transforming growth factor (TGF)-beta, Eotaxin3, vascular adhesion protein-1 (VAP-1) and monokine induced by interferon-gamma (MIG) as potential atherosclerotic target genes in severe calcified and stenotic aortic valves, and analyzes the effects of statins on their expression as part of an anti-inflammatory treatment strategy. We collected human severe calcified and stenotic aortic valves with (CSAV+) or without (CSAV-) statin pre-treatment prior to valve replacement and investigated gene profiling by using micro-array technique and real-time PCR for the TGF-beta, Eotaxin3, VAP-1 and MIG expression. In comparison to atherosclerotic plaques of carotid arteries, immunohistochemical staining was investigated. Results were contrasted to human normal non-calcified aortic valves as controls (C). As compared to C, TGF-beta, Eotaxin3, MIG or VAP-1 was significantly upregulated in CSAV-. In CSAV+ no significant change in gene expression was found for Eotaxin3 and MIG. In contrast, VAP-1 and TGF-beta were still upregulated. Corresponding gene expression was confirmed on atherosclerotic plaque formations of carotid arteries. Monocyte/Macrophage infiltration (presence of CD68) on aortic valves (CSAV+, CSAV-, or C) confirmed inflammatory nature of the disease. Our data support further evidence for atherosclerotic inflammation as a trigger for sclerosis in end-stage calcified stenotic aortic valves by showing upregulation of gene expression for TGF-beta, VAP-1, MIG and Eotaxin3, which is only partially inhibited by previous statin therapy. Potent benefits of statin treatment on early stages of valve disease are still propagated.
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PMID:VAP-1, Eotaxin3 and MIG as potential atherosclerotic triggers of severe calcified and stenotic human aortic valves: effects of statins. 1749 Jun 41

The offspring of type 2 diabetic patients are at elevated risk for type 2 diabetes and cardiovascular disease. The aim of our study was to characterize the role of various biomarkers of endothelial activation in a cohort of offspring of type 2 diabetic subjects and to assess the association of adhesion molecules with inflammatory markers and metabolic parameters. Cytokine and adhesion molecule levels were measured in 19 healthy subjects and in 129 offspring of patients with type 2 diabetes (109 with normal glucose tolerance and 20 with impaired glucose tolerance). Insulin sensitivity was determined with the hyperinsulinemic-euglycemic clamp, insulin secretion with the intravenous glucose tolerance test, and abdominal fat distribution with computed tomography. The levels of vascular cell adhesion molecule-1, intercellular adhesion molecule-1, E-Selectin and vascular adhesion protein-1 were not increased in offspring of type 2 diabetic subjects, but they correlated with inflammatory markers (C-reactive protein, tumor necrosis-alpha, interleukin-6, interleukin-1 beta, interleukin-1 receptor antagonist, interleukin-8, interleukin-10 and interleukin-18). In conclusion, the levels of adhesion molecules were not elevated in the prediabetic state. Inflammatory markers and adhesion molecules were correlated suggesting that low-grade inflammation may precede the elevation of levels of adhesion molecules.
Atherosclerosis 2008 Mar
PMID:Markers of endothelial dysfunction and low-grade inflammation are associated in the offspring of type 2 diabetic subjects. 1756 May 80

Adipose tissue plays an active role in normal metabolic homeostasis as well as in the development of human diseases such as atherosclerosis and diabetes. We report here antimicrobial activities of the metabolites from adipocytes. Specifically, semicarbazide-sensitive amine oxidase of differentiated 3T3-L1 cells was found to utilize methylamine for producing formaldehyde and hydrogen peroxide, accounting for the inhibition of infectivity of Toxoplasma gondii and its replication in these cells. This was demonstrated by the findings that semicarbazide-sensitive amine oxidase was extremely high in differentiated 3T3-L1 cells; and that the infection of these cells by T. gondii and its intracellular replication were decreased to 33% and 37% of the control, respectively, when methylamine was provided in micromolar concentrations as the substrate to the aminoxidase. Only one of the two reaction products expected was found inhibitory against T. gondii when added to the infected pre-adipocytes of 3T3-L1. Intracellular replication of this parasite was inhibited by formaldehyde in the range of 10-100 microM and stimulated by hydrogen peroxide at 1-10 microM. The finding indicates that T. gondii may be useful as a sensitive and convenient sentinel for screening agents toxic to eukaryotic cells.
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PMID:Toxicity of derivatives from semicarbazide-sensitive amine oxidase-mediated deamination of methylamine against Toxoplasma gondii after infection of differentiated 3T3-L1 cells. 2002 55

Endogenous formaldehyde is produced via semicarbazide-sensitive amine oxidase-catalyzed deamination of methylamine. It widely exists in a variety of tissues and cells in animals. It has been confirmed that endogenous formaldehyde is involved in the neural degeneration, immune disease and tumor process. Adipocytes, vascular endothelial cells and smooth muscle cells are rich in enzyme to generate formaldehyde-semicarbazide-sensitive amine oxidase (SSAO). Formaldehyde may cause cytotoxicity, which induces vascular endothelial injury and mediates multiple factor-induced pathogenic process of vascular injury. It plays important role in atherosclerosis, diabetes mellitus and diabetic complication.
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PMID:[Endogenous formaldehyde and cardiovascular diseases]. 2141 9


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