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)

Low-density lipoprotein oxidation is believed to play an important role in the development of atherosclerosis and therefore a high resistance of LDL against oxidation may prevent atherogenesis and accompanying disorders. Several secondary plant metabolites have been tested for their ability to prevent oxidation of LDL and many phenolics as well as carotenoids have been shown to enhance LDL oxidation resistance. We showed that the quercetingylcoside rutin is able to inhibit copper-induced formation of conjugated dienes and loss of tryptophan fluorescence in LDL. However, enrichment of LDL with the carotenoids lutein or lycopene did not result in an alleviation of LDL oxidation. Since there is an agreement that not one antioxidant alone can lead to health benefits but the combination, as found for example in fruits and vegetables, is the active principle, we tested whether the combination of a phenolic compound (i. e. rutin) and carotenoids (i.e. lutein or lycopene) leads to synergistic effects. Both combinations were shown to exert supra-additive protection of LDL towards oxidation, which is most likely due to different allocation of the antioxidants in the LDL-particle and to different mechanisms of antioxidant action.
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PMID:Synergistic effects of phenolics and carotenoids on human low-density lipoprotein oxidation. 1763 13

Atherosclerosis and graft arteriosclerosis are characterized by leukocytic infiltration of the vessel wall that spares the media. The mechanism(s) for medial immunoprivilege is unknown. In a chimeric humanized mouse model of allograft rejection, medial immunoprivilege was associated with expression of IDO by vascular smooth muscle cells (VSMCs) of rejecting human coronary artery grafts. Inhibition of IDO by 1-methyl-tryptophan (1-MT) increased medial infiltration by allogeneic T cells and increased VSMC loss. IFN-gamma-induced IDO expression and activity in cultured human VSMCs was considerably greater than in endothelial cells (ECs) or T cells. IFN-gamma-treated VSMCs, but not untreated VSMCs nor ECs with or without IFN-gamma pretreatment, inhibited memory Th cell alloresponses across a semipermeable membrane in vitro. This effect was reversed by 1-MT treatment or tryptophan supplementation and replicated by the absence of tryptophan, but not by addition of tryptophan metabolites. However, IFN-gamma-treated VSMCs did not activate allogeneic memory Th cells, even after addition of 1-MT or tryptophan. Our work extends the concept of medial immunoprivilege to include immune regulation, establishes the compartmentalization of immune responses within the vessel wall due to distinct microenvironments, and demonstrates a duality of stimulatory EC signals versus inhibitory VSMC signals to artery-infiltrating T cells that may contribute to the chronicity of arteriosclerotic diseases.
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PMID:Induction of indoleamine 2,3-dioxygenase in vascular smooth muscle cells by interferon-gamma contributes to medial immunoprivilege. 1791 10

Myeloperoxidase (MPO) binds H2O2 in the absence and presence of chloride (Cl-) and catalyzes the formation of potent oxidants through 1e(-) and 2e(-) oxidation pathways. These potent oxidants have been implicated in the pathogenesis of various diseases including atherosclerosis, asthma, arthritis, and cancer. Thus, inhibition of MPO and its by-products may have a wide application in biological systems. Using direct rapid kinetic measurements and H2O2-selective electrodes, we show that tryptophan (Trp), an essential amino acid, is linked kinetically to the inhibition of MPO catalysis under physiological conditions. Trp inactivated MPO in the absence and presence of plasma levels of Cl(-), to various degrees, through binding to MPO, forming the inactive complexes Trp-MPO and Trp-MPO-Cl, and accelerating formation of MPO Compound II, an inactive form of MPO. Inactivation of MPO was mirrored by the direct conversion of MPO-Fe(III) to MPO Compound II without any sign of Compound I accumulation. This behavior indicates that Trp binding modulates the formation of MPO intermediates and their decay rates. Importantly, Trp is a poor substrate for MPO Compound II and has no role in destabilizing complex formation. Thus, the overall MPO catalytic activity will be limited by: (1) the dissociation of Trp from Trp-MPO and Trp-MPO-Cl complexes, (2) the affinity of MPO Compound I toward Cl(-) versus Trp, and (3) the slow conversion of MPO Compound II to MPO-Fe(III). Importantly, Trp-dependent inhibition of MPO occurred at a wide range of concentrations that span various physiological and supplemental ranges.
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PMID:Potential role of tryptophan and chloride in the inhibition of human myeloperoxidase. 1827 80

Increased oxidative stress (SOX), inflammation and prevalence of cardiovascular disease (CVD) have been reported in end-stage renal disease (ESRD), but their associations with kynurenine (KYN) pathway activation remain unknown. We determined the plasma concentrations of tryptophan (TRP), KYN, 3-hydroxykynurenine (3-HKYN); two distinct SOX markers: Cu/Zn superoxide dismutase (Cu/Zn SOD) and total peroxide; and high sensitivity C-reactive protein (hs CRP) as a indicator of inflammation in 146 ESRD patients and healthy controls. Analysis of TRP degradation through the KYN pathway demonstrated that in uremia the concentrations of this aminoacid were decreased by 40-60% in comparison with controls. In contrast, the plasma levels of KYN and 3-HKYN in ESRD patients were increased by 32-96% and 184-306%, respectively. These changes were accompanied by significant increase in the kyn/trp ratios by 140-240%, and 3-hkyn/kyn ratios by 40-154% in uremics compared to controls. ESRD patients showed a significant increase in Cu/Zn SOD, total peroxide and hs CRP levels between controls and all patients group. KYN and 3-HKYN were positively associated with inflammation and SOX markers in uremics. Logistic regression analysis showed that age, gender, presence of DM (all p<0.001), elevated hs CRP (p<0.01) and 3-HKYN levels (p<0.05) were independently associated with the presence of CVD in this population. These results suggest a relationship between KYN pathway activation and increased SOX, inflammation and CVD prevalence in ESRD patients.
Atherosclerosis 2009 May
PMID:The kynurenines are associated with oxidative stress, inflammation and the prevalence of cardiovascular disease in patients with end-stage renal disease. 1882 90

Chlamydia pneumoniae is a community-acquired respiratory pathogen that has been associated with the development of atherosclerosis. Analysis of the C. pneumoniae genome identified a gene (Cpn1046) homologous to eukaryotic aromatic amino acid hydroxylases (AroAA-Hs). AroAA-Hs hydroxylate phenylalanine, tyrosine, and tryptophan into tyrosine, dihydroxyphenylalanine, and 5-hydroxytryptophan, respectively. Sequence analysis of Cpn1046 demonstrated that residues essential for AroAA-H enzymatic function are conserved and that a subset of Chlamydia species contain an AroAA-H homolog. The chlamydial AroAA-Hs are transcriptionally linked to a putative bacterial membrane transport protein. We determined that recombinant Cpn1046 is able to hydroxylate phenylalanine, tyrosine, and tryptophan with roughly equivalent activity for all three substrates. Cpn1046 is expressed within 24 h of infection, allowing C. pneumoniae to hydroxylate host stores of aromatic amino acids during the period of logarithmic bacterial growth. From these results we can conclude that C. pneumoniae, as well as a subset of other Chlamydia species, encode an AroAA-H that is able to use all three aromatic amino acids as substrates. The maintenance of this gene within a number of Chlamydia suggests that the enzyme may have an important role in shaping the metabolism or overall pathogenesis of these bacteria.
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PMID:Chlamydia pneumoniae encodes a functional aromatic amino acid hydroxylase. 1914 Nov 12

Given the very difficult odyssey of my early years, who could have imagined the incredible and successful journey that constituted my life path after age 13? I was born into a Jewish family in Breslau, Germany, right before the rise of Nazism and Hitler's election. After Kristallnacht, when my father was taken to Buchenwald Concentration Camp, we had to leave Germany as soon as possible. The first opportunity came in May of 1939, when we boarded the SS St. Louis bound for Havana, Cuba. Almost all passengers were denied entrance into Cuba, and the ship had to go back to Europe, where I ended up in France. In December of 1939, during World War II, I was fortunate to be able to leave France. This time I made it to Cuba, where my father was already in residence. A year later, my entire family was allowed into the United States. I took advantage of all the educational resources in this land of opportunity. I graduated valedictorian of my high school class and earned a four-year scholarship to Rutgers University, where I obtained a Bachelor of Science degree. I went on to earn a Master's degree from the University of Connecticut and finally a PhD from the University of Illinois. Within two months after graduating from Illinois, I was hired as an assistant professor of nutritional biochemistry at Rutgers, where I enjoyed a most productive research and teaching career. My PhD research involved tryptophan and niacin metabolism in the chick, and upon arrival at Rutgers I continued amino acid studies with the goal of assessing the essential amino acid requirements for egg production. This research was crowned with success and was followed with amino acid requirement studies for maintenance and for growth in rabbits, and ultimately with a reevaluation of requirements in adult humans. An outgrowth of the maintenance requirements led to a series of investigations into the metabolism of histidine, histamine, and carnosine (a histidine-containing dipeptide). Histamine, we found, plays an important role in wound healing and stress management. Pyridoxal phosphate is the cofactor for the enzyme histidine decarboxylase required for histamine synthesis and similarly serves as a cofactor for hydroxytryptophan decarboxylase, the enzyme that is part of the pathway to serotonin synthesis. Investigations into these pathways led to interesting findings: brain concentrations of serotonin could be increased by supplementing the diet of rats with tryptophan and pyridoxine; the elevated brain serotonin levels had behavioral consequences. Alcohol craving, addiction, and withdrawal symptoms are affected by serotonin concentrations in the brain, and alleviation of these conditions can be achieved with simultaneous administration of serotonin and dopamine agonists. In the midst of our early amino acid studies, we serendipitously also became involved with lipid metabolism in relation to atherosclerosis and blood cholesterol in a chicken model. This work led to the recognition that soluble fibers, like pectin, had strong cholesterol-lowering properties that were beneficial in lowering the incidence of coronary plaque formation. The research success that I have enjoyed has been coupled with the gift of three accomplished children who are making important contributions as professionals in their fields of endeavor. My wife and I are also blessed with 10 wonderful grandchildren, our pride and joy!
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PMID:From tryptophan to hydroxytryptophan: reflections on a busy life. 1940 Jul 2

The abnormalities of tissue factor (TF) and its inhibitor (TFPI) system could potentially contribute to high incidence of thrombotic complications and atherosclerosis in patients with chronic kidney disease (CKD). Recently, the role of the kynurenine (KYN) pathway of tryptophan (TRP) degradation has been postulated in the progression of cardiovascular complications. We compared the plasma TF, TFPI and the metabolites of TRP degradation: KYN and 3-hydroxykynurenine (3-HKYN) levels in 55 CKD patients on conservative treatment and 19 healthy controls; and we tried to establish whether or not there is an association between TF/TFPI system and above-mentioned metabolites in these patients. Compared with the controls, the patients with CKD showed a significant increase in plasma concentrations of TF (P < 0.01), KYN, 3-HKYN (both P < 0.0001), KYN-to-TRP (kyn/trp) ratio (P < 0.001) and 3-HKYN-to-KYN (3-hkyn/kyn) ratio (P < 0.05). In contrast, TRP concentrations were significantly decreased in the CKD group compared with controls (P < 0.001). The difference in TFPI levels between CKD patients and controls was not statistically significant. TF/TFPI system was inversely correlated with TRP, whereas it was positively related to the 3-HKYN, kyn/trp and 3-hkyn/kyn ratios. Moreover, both the TF/TFPI system and KYNs were associated with the markers of kidney function. These data suggested for the first time a significant relationship between TF/TFPI system and KYN pathway in CKD patients on conservative treatment.
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PMID:Tissue factor/its pathway inhibitor system and kynurenines in chronic kidney disease patients on conservative treatment. 1949 64

Patients with end-stage renal disease (ESRD) exhibit features of a hypercoagulable state, which may contribute to atherosclerosis. Kynurenines are the metabolites of tryptophan degradation in mammals. We examined the relationship between coagulation activation and kynurenines in 92 patients with ESRD on maintenance haemodialysis (HD) or continuous ambulatory peritoneal dialysis (CAPD) and 20 healthy controls. We measured the plasma levels of: tissue factor (TF), its pathway inhibitor (TFPI), the marker of coagulation activation - prothrombin fragments 1+2 (F(1+2)), kynurenine (KYN) and its metabolites: kynurenic (KYNA), anthranilic (AA) and quinolinic (QA) acids. The ratio of KYNA to KYN (kyna/kyn), AA to KYN (aa/kyn) and QA to KYN (qa/kyn), reflecting intensified activity of enzymes which converted KYN to its metabolites, were also determined. Measured coagulation parameters and kynurenines were significantly elevated in ESRD patients compared to controls. TF, TFPI and F(1+2) were significantly associated with AA, aa/kyn, QA and qa/kyn ratio. Multiple regression analysis showed that fibrinogen (p<0.01) and above mentioned KYN metabolites (all p<0.05) were the independent variables significantly associated with increased F(1+2) levels, reflecting hypercoagulability in ESRD patients. In conclusion, this study represents the first to investigate both the coagulation system and KYN pathway in ESRD patients. The coagulation was enhanced in dialysed uraemic patients compared with the healthy controls demonstrated by increased TF, TFPI and F(1+2) levels. These changes were correlated with activation of the KYN pathway. Finally, fibrinogen and KYN metabolites are independently and significantly associated with the hypercoagulable state in uraemic patients on CAPD and HD treatment.
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PMID:Hypercoagulability is independently associated with kynurenine pathway activation in dialysed uraemic patients. 1957 67

An ultra fast liquid chromatography coupled with IT-TOF mass spectrometry (UFLC/MS-IT-TOF) metabonomic approach was employed to study the plasma and urine metabolic profiling of atherosclerosis rats. Acquired data were subjected to principal component analysis (PCA) for differentiating the atherosclerosis and the control groups. Potential biomarkers were screened by using S-plot and were identified by the accurate mass and MS(n) fragments information obtained from UFLC/MS-IT-TOF analysis. 12 metabolites in rat plasma and 8 metabolites in urine were identified as potential biomarkers. Concentrations of leucine, phenylalanine, tryptophan, acetylcarnitine, butyrylcarnitine, propionylcarnitine and spermine in plasma and 3-O-methyl-dopa, ethyl N2-acetyl-L-argininate, leucylproline, glucuronate, t6A N(6)-(N-threonylcarbonyl)-adenosine and methyl-hippuric acid in urine decreased in atherosclerosis rats. Ursodeoxycholic acid, chenodeoxycholic acid, LPC (C16:0), LPC (C18:0) and LPC (C18:1) in plasma and hippuric acid in urine were in higher levels in atherosclerosis rats. The alterated metabolites demonstrated abnormal metabolism of phenylalanine, tryptophan, bile acids and amino acids. This research proved that metabonomics is a promising tool for disease research.
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PMID:Metabonomics study of atherosclerosis rats by ultra fast liquid chromatography coupled with ion trap-time of flight mass spectrometry. 1957 53

Infection with Chlamydia pneumoniae, a human respiratory pathogen, has been associated with various chronic diseases such as asthma and atherosclerosis, possibly because the pathogen can exist in a persistent form. C. pneumoniae persistently infect DCs in a TNF-alpha dependent manner. The present study investigated whether C. pneumoniae infection can induce indoleamine 2,3-dioxygenase (IDO) activity in dendritic cells, and whether the restriction of chlamydial growth in the DCs by TNF-alpha is IDO dependent. Our data indicate that infection of DCs with C. pneumoniae resulted in the induction of IDO expression. Reporting on our use of anti-TNF-alpha antibody adalimumab and varying concentrations of TNF-alpha, we further demonstrate that IDO induction following infection of DCs with C. pneumoniae is TNF-alpha dependent. The anti-chlamydial activity induced by TNF-alpha and the expression of chlamydial 16S rRNA gene, euo, groEL1, ftsk and tal genes were correlated with induction of IDO. Addition of excess amounts of tryptophan to the DC cultures resulted in abrogation of the TNF-alpha-mediated chlamydial growth restriction. These findings suggest that infection of DCs by C. pneumoniae induces production of functional IDO, which subsequently causes depletion of tryptophan. This may represent a potential mechanism for DCs to restrict bacterial growth in chlamydial infections.
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PMID:Restriction of Chlamydia pneumoniae replication in human dendritic cell by activation of indoleamine 2,3-dioxygenase. 1964


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