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)

Adiponectin is a novel polypeptide that is highly specific to adipose tissue. In contrast to other adipocytokines, adiponectin levels are decreased in obesity and associated comorbidities, such as type 2 diabetes. Decreased expression of adiponectin is correlated with insulin resistance. It has been suggested that several agents, such as tumor necrosis factor alpha, could mediate their effects on insulin metabolism through modulating adiponectin secretion from adipocytes. The mechanisms for the development of atherosclerotic vascular disease in obese individuals are largely unknown. Several findings support the interesting hypothesis that adiponectin could be a link between obesity and related atherosclerosis. First, adiponectin levels are lower in patients with coronary artery disease. Second, adiponectin modulates endothelial function and has an inhibitory effect on vascular smooth muscle cell proliferation. Moreover, adiponectin is accumulated more preferably to the injured vascular wall than intact vessels and has been shown to suppress macrophage-to-foam cell transformation. Adiponectin may also be involved in the modulation of inflammation. Thiazolidinediones, antiatherogenic and other effects have been explained by their direct enhancing effect on adiponectin. In conclusion, adiponectin has anti-inflammatory and antiatherogeneic effects as well as multiple beneficial effects on metabolism. Therefore it is not a surprise that adiponectin therapy has been tested in animal models of obesity, and it has been shown to ameliorate hyperglycemia and hyperinsulinemia without inducing weight gain or even inducing weight loss in some studies. Unlike agents that exert their effects centrally, adiponectin's effects seem to be peripherally mediated. The evidence of an association between adiponectin and the metabolic and cardiovascular complications of obesity is growing all the time.
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PMID:Adiponectin: a link between excess adiposity and associated comorbidities? 1243 46

Matrix metalloproteinases (MMPs) are zinc endopeptidases that degrade extracellular matrix (ECM) components during normal and pathogenic tissue remodeling. Inappropriate expression of these enzymes contributes to the development of vascular pathology, including atherosclerosis. MMP-9 is expressed in its active form in atherosclerotic lesions and is believed to play an important role in vascular remodeling, smooth muscle cell migration, and plaque instability. We demonstrate here that the liver X receptors (LXRs) LXRalpha and LXRbeta inhibit basal and cytokine-inducible expression of MMP-9. Treatment of murine peritoneal macrophages with the synthetic LXR agonists GW3965 or T1317 reduces MMP-9 mRNA expression and blunts its induction by pro-inflammatory stimuli including lipopolysaccharide, interleukin-1beta, and tumor necrosis factor alpha. In contrast, macrophage expression of MMP-12 and MMP-13 is not altered by LXR ligands. We further show that the ability of LXR ligands to regulate MMP-9 expression is strictly receptor-dependent and is not observed in macrophages obtained from LXRalphabeta null mice. Analysis of the 5'-flanking region of the MMP-9 gene indicates that LXR/RXR heterodimers do not bind directly to the MMP-9 promoter. Rather, activation of LXRs represses MMP-9 expression, at least in part through antagonism of the NFkappaB signaling pathway. These observations identify the regulation of macrophage MMP-9 expression as a mechanism whereby activation of LXRs may impact macrophage inflammatory responses.
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PMID:Liver X receptor-dependent repression of matrix metalloproteinase-9 expression in macrophages. 1253 95

Increased levels of triglyceride-rich lipoproteins provoke lipid accumulation in the artery wall, triggering early inflammatory responses central to atherosclerosis like endothelial adhesion molecule expression. The endogenous mechanisms limiting such reactions remain poorly defined. Lipoprotein lipase (LPL) plays a central role in lipid metabolism by hydrolyzing triglyceride rich lipoproteins and releasing fatty acids. We found that LPL treatment reversed tumor necrosis factor alpha and very low-density lipoprotein (VLDL)-stimulated endothelial vascular cell adhesion molecule 1 (VCAM1) induction and VCAM1 promoter responses, thus recapitulating effects reported with synthetic peroxisome proliferator-activated receptor (PPAR) agonists. In fact, these LPL effects on VCAM1 were absent in endothelial cells isolated from PPAR alpha-deficient mice. This finding suggests a novel antiinflammatory role for LPL. Further studies reveal specificity for PPAR activation through lipolysis in regards to lipoprotein substrate (VLDL >> LDL > HDL), PPAR isoform (PPAR alpha >> PPAR delta > PPAR gamma), and among fatty acid-releasing lipases. These PPAR responses required intact LPL catalytic activity. In vivo, transgenic mice overexpressing LPL had increased peroxisome proliferation, but not in the genetic absence of PPAR alpha. Although human plasma possesses minimal PPAR alpha activation despite containing abundant free fatty acids, marked PPAR alpha activation is seen with human plasma after LPL is added in vitro or systemically released in vivo. These data suggest a previously uncharacterized pathway in which the key lipolytic enzyme LPL can act on circulating lipoproteins to generate PPAR alpha ligands, providing a potentially important link between lipoprotein metabolism and distal PPAR alpha transcriptional effects.
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PMID:Lipolysis of triglyceride-rich lipoproteins generates PPAR ligands: evidence for an antiinflammatory role for lipoprotein lipase. 1260 19

Type 2 diabetic mellitus (type 2 DM) comprises more than 95% of all Taiwanese patients with DM. Tumor necrosis factor-alpha (TNF-alpha) expression is linked with insulin resistance, and is under strong genetic control. The correlation between TNF promoter genotypes and type 2 DM is still controversial, because discrepancies among different studies exist. Ethnic differences play certain roles in these conflicting results, because the distribution of TNF promoter polymorphisms is different among study subjects with different racial origins. Therefore, we examined the relationship between the incidence of type 2 diabetes in Taiwanese and two polymorphisms of the TNF-alpha promoter region (positions -238 and -308) as well as the correlation between these polymorphisms and the patients' biochemical manifestations. Genomic DNA was extracted from peripheral blood cells of 261 Taiwanese patients with type 2 DM and 189 non-diabetic control study subjects, and their TNF promoter G-238A and G-308A polymorphisms were analyzed by PCR-RFLP analysis. No significant association between TNF-alpha G-238A and G-308A polymorphisms with type 2 diabetic incidence was observed. However, associations between TNF-alpha G-238A and low-density lipoprotein-cholesterol and between G-308A promoter polymorphism and high-fasting plasma glucose levels, using multiple linear regression analysis with adjustment for the subjects' age, sex, body mass index and diabetic status, were found. Our results suggested that though TNF-alpha G-238A and G-308A polymorphisms were not involved in the pathogenesis of type 2 DM, type 2 diabetic patients carrying TNFA-A or TNF-308*2 genotype might be more susceptible to diabetic complications such as atherosclerosis.
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PMID:TNF-alpha polymorphisms and type 2 diabetes mellitus in Taiwanese patients. 1275 58

Endothelin-1 (ET-1) is a pleiotropic hormone produced primarily by the endothelium. Synthesis of ET-1 is stimulated by the major signals of cardiovascular stress, such as vasoactive agents (angiotensin II, norepinephrine, vasopressin, and bradykinin), cytokines (e.g., tumor necrosis factor alpha and transforming growth factor beta), and other factors, including thrombin and mechanical stress. ET-1 induces vasoconstriction, is proinflammatory, promotes fibrosis, and has mitogenic potential, important factors in the regulation of vascular tone, arterial remodeling, and vascular injury. These effects are mediated via two receptor types, ETA and ETB. The role ET-1 plays in normal cardiovascular homeostasis and in mild essential hypertension in humans is unclear. However, certain groups of essential hypertensive patients may have ET-1-dependent hypertension, including blacks (subjects of African descent), salt-sensitive hypertensives, patients with low renin hypertension, and those with obesity and insulin resistance. ET-1 has also been implicated in severe hypertension, heart failure, atherosclerosis, and pulmonary hypertension. In all of these conditions, plasma immunoreactive ET levels are elevated and tissue ET-1 expression is increased. Accordingly, it is becoming increasingly apparent that ET-1 plays an important role in cardiovascular disease and in some forms of hypertension in humans. Data from clinical trials using combined ETA-ETB receptor blockers have already demonstrated significant blood-pressure-lowering effects. Thus, targeting the endothelin system may have important therapeutic potential in the treatment of hypertension, particularly by contributing to the prevention of target organ damage and the management of cardiovascular disease.
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PMID:Role of endothelin in human hypertension. 1283 65

Atherosclerosis can to a certain extent be regarded as an inflammatory disease. Also, inflammatory markers may provide information about cardiovascular risk. Whether macrolide antibiotics, especially clarithromycin, have an anti-inflammatory effect in patients with atherosclerosis is not exactly known. To study this phenomenon, a placebo-controlled, randomized, double-blind study was performed. A total of 231 patients with documented coronary artery disease received a daily dose of either 500 mg of slow-release clarithromycin or placebo until the day of surgery. Levels of inflammatory markers (C-reactive protein, interleukin-2 receptor [IL-2R], IL-6, IL-8, and tumor necrosis factor alpha) were assessed during the preoperative outpatient visit, on the day of surgery, and 8 weeks after surgery. Also, changes in the levels of inflammatory markers between visits were determined by delta calculations. Baseline patient characteristics were balanced between the two treatment groups: the average age was 66 years (standard deviation [SD] = 9.0), 79% of the patients were male, and the average number of tablets used was 16 (SD = 9.3). The inflammatory markers of the groups as well as the delta calculations were not significantly changed. Treatment with clarithromycin did not influence the inflammatory markers in patients with atherosclerosis.
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PMID:Effect of clarithromycin on inflammatory markers in patients with atherosclerosis. 1285 80

Peripheral arterial disease (PAD) is a common manifestation of atherosclerosis that is associated with systemic inflammation. The aim of our study was to assess whether plasma markers of inflammation increased after exercise in patients with PAD. The study was conducted on two groups of 20 subjects each: one group (mean age 68.4 +/- 5.09 years) was affected by PAD with claudication, while the other group consisted of healthy controls (66.9 +/- 6.1 years). Concentrations of interleukin 6 (IL-6) and tumor necrosis factor alpha (TNFalpha) were determined in plasma, in supernatants and in cells stimulated with 1 mg lipopolysaccharide in all patients. E-selectin (ES), L-selectin (LS) and P-selectin (PS) concentrations and plasma concentrations of VCAM-1 and ICAM-1 were also determined. All determinations were performed in patients at rest and after the treadmill exercise. Resting values of soluble mediators were greater in PAD patients than in controls. They increased in both groups after the treadmill test, even if post-treadmill concentrations were significantly higher in PAD patients (PAD p < 0.001 or 0.0001, controls p < 0.05 or 0.001). These results confirm that white blood cell activation is characteristic of systemic atherosclerosis and that these inflammation markers increase in conditions of hemodynamic stress.
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PMID:High circulating levels of cytokines (IL-6 and TNFalpha), adhesion molecules (VCAM-1 and ICAM-1) and selectins in patients with peripheral arterial disease at rest and after a treadmill test. 1286 7

Low density lipoprotein (LDL) exists in various forms that possess unique characteristics, including particle content and metabolism. One circulating subfraction, electronegative LDL (LDL(-)), which is increased in familial hypercholesterolemia and diabetes, is implicated in accelerated atherosclerosis. Cellular responses to LDL(-) remain poorly described. Here we demonstrate that LDL(-) increases tumor necrosis factor alpha (TNFalpha)-induced inflammatory responses through NF kappa B and AP-1 activation with corresponding increases in vascular cell adhesion molecule-1 (VCAM1) expression. LDL receptor overexpression increased these effects. In contrast, exposing LDL(-) to the key lipolytic enzyme lipoprotein lipase (LPL) reversed these responses, inhibiting VCAM1 below levels seen with TNFalpha alone. LPL is known to act on lipoproteins to generate endogenous peroxisomal proliferator-activated receptor alpha (PPAR alpha) ligand, thus limiting inflammation. These responses varied according to the lipoprotein substrate triglyceride content (very low density lipoprotein >> LDL > high density lipoprotein). The PPAR alpha activation seen with LDL, however, was disproportionately high. We show here that MUT LDL activates PPAR alpha to an extent proportional to its LDL(-) content. As compared with LDL(-) alone, LPL-treated LDL(-) increased PPAR alpha activation 20-fold in either cell-based transfection or radioligand displacement assays. LPL-treated LDL(-) suppressed NF kappa B and AP-1 activation, increasing expression of the PPAR alpha target gene I kappa B alpha, although only in the genetic presence of PPAR alpha and with intact LPL hydrolysis. Mass spectrometry reveals that LPL-treatment of either LDL or LDL(-) releases hydroxy-octadecadienoic acids (HODEs), potent PPAR alpha activators. These findings suggest LPL-mediated PPAR alpha activation as an alternative catabolic pathway that may limit inflammatory responses to LDL(-).
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PMID:Dual roles for lipolysis and oxidation in peroxisome proliferation-activator receptor responses to electronegative low density lipoprotein. 1287 89

Purpose of this study was to investigate the effect of combined administration of antioxidant vitamins C and E on endothelial function and serum levels of inflammatory markers such as tumor necrosis factor alpha (TNF-alpha), interleukines 1b (IL-1b) and 6 (IL-6), vascular cell adhesion molecule-1 (VCAM-1), intercellular adhesion molecule-1 (ICAM-1) and E-selectin in chronic smokers. Forty-three smokers were randomly divided into four groups receiving vitamin C 2 g/day (group A), vitamin C 2 g/day plus vitamin E 400 IU/day (group B), vitamin C 2 g/day plus vitamin E 800 IU/day (group C) or no antioxidant treatment (group D), for 4 weeks. Forearm blood flow (FBF) was measured using venous occlusion strain gauge plethysmography. Forearm vasodilatory response to reactive hyperemia (RH%) was expressed as the percentage change from baseline to post reactive hyperemia blood flow. RH% was significantly increased in groups B (P<0.05) and C (P<0.01), but remained unaffected in groups A and D. Serum levels of IL-1b, IL-6, sVCAM-1 and sICAM-1 were significantly reduced in group C (P<0.05, respectively), but remained unaffected in groups A, B and D. Thus, short term administration of vitamins C (2 g/day) and E (800 IU/day) reduces serum levels of IL-1b, IL-6, sVCAM-1 and sICAM-1, and improves forearm vasodilatory response to reactive hyperemia in healthy young smokers, while monotherapy with vitamin C alone is ineffective.
Atherosclerosis 2003 Oct
PMID:Effects of combined administration of vitamins C and E on reactive hyperemia and inflammatory process in chronic smokers. 1461 6

An intercross between atherosclerosis susceptible (C57BL/6J ApoE0) and resistant (FVB/N ApoE0) mice revealed a susceptibility locus on chromosome 10 (11 cM, logarithm of odds 7.8). Surprisingly, the genotypic means for this locus revealed that heterozygosity or homozygosity for the C57BL/6J allele was associated with decreased atherosclerosis. A candidate gene in this region is A20, which is involved in the feedback suppression of NFkappaB activation induced by tumor necrosis factor alpha (TNFalpha). We sequenced the A20 gene coding region from the parental strains and found a single-nucleotide polymorphism resulting in a single amino acid exchange, Glu627Ala (C57BL/6J vs. FVB/N). This mutation introduces a putative casein kinase 2 phosphorylation site in C57BL/6J-A20 not present in FVB/N-A20. NFkappaB reporter gene assays showed that this amino acid change results in less effective termination of TNFalpha-stimulated NFkappaB activation by C57BL/6J-A20. In accordance, the TNFalpha-induced expression of NFkappaB target genes (A20, IkappaBalpha) in vascular smooth muscle cells was prolonged in cells isolated from C57BL/6J compared with FVB/N mice. In light of the genotypic means for atherosclerosis at the chromosome 10 locus in F2 mice from this intercross, the observations now reported suggest that prolonged expression of genes induced by NFkappaB might be antirather than proatherogenic.
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PMID:A20, a regulator of NFkappaB, maps to an atherosclerosis locus and differs between parental sensitive C57BL/6J and resistant FVB/N strains. 1461 51


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