UMLS:C0020538 - FACTA Search

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Query: UMLS:C0020538 (hypertension)
170,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Recently, the current authors reported the presence in normotensive male and female urines of reproducibly measurable levels of naturally occurring substances in partially purified extracts of urine with inhibitory activity like glycyrrhetic acid (GA) towards both 11 beta-hydroxysteroid dehydrogenase (11 beta-OHSD) and steroid 5 beta-reductase (5 beta-SR) in vitro. Since these substances mimic two known inhibitory activities of GA, they have been named 'Glycyrrhetic Acid-Like Factors', abbreviated as 'GALFs' or, more specifically 11 beta-GALF for substance(s) active against 11 beta-OHSD, and 5 beta-GALF for those inhibitory to 5 beta-SR. Administration of glycyrrhetic acid in man leads to cortisol-dependent mineralocorticoid hypertension, owing to impaired inactivation of cortisol by 11 beta-OHSD, and may be associated with increased sensitivity to mineralocorticoids owing to impaired 5 beta-SR. In this preliminary report, the results are described of a study on the presence of GALF factors in urines collected from patients with congestive heart failure (CHF) and mild essential hypertension. The results show that in such patients there are increased amounts of both 11 beta- and 5 beta- GALFs compared to normotensive. The possible physiological significance of these results is discussed.
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PMID:Inhibitors of 11 beta-hydroxysteroid dehydrogenase and 5 beta-steroid reductase in urine from patients with congestive heart failure. 829

The concurrence of hypertension and hypercholesterolemia leads to the clinical need to lower lipids in hypertensive patients. Thus, it is interesting to evaluate the efficacy and safety of fluvastatin, a new 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA)-reductase inhibitor, in such a patient population. A retrospective analysis of the clinical efficacy and safety of fluvastatin was based on the data from 1815 patients who received fluvastatin at daily doses of > or = 20 mg compared with 783 patients taking placebo. The results showed that 332 (18.3%) of the fluvastatin-treated and 124 (15.8%) of the placebo-treated patients were identified as having hypertension. The percentage change from baseline of low-density lipoprotein cholesterol (LDL-C) in hypertensive patients taking fluvastatin at doses of 20 and 40 mg/day was -20% and -26%, respectively (placebo: 1.4%), and did not differ from the response in non-hypertensive patients. Increases in high-density lipoprotein cholesterol (HDL-C) as well as decreases in triglycerides with fluvastatin were not consistently different between hypertensive and non-hypertensive patients. Irrespective of the presence or absence of hypertension, confirmed (measured on two consecutive occasions) increases > three times the upper limit of normal in aspartate aminotransferase (ASAT) and alanine aminotransferase (ALAT) were observed in three (0.2%) and 12 (0.7%) patients, respectively. With placebo, ALAT was increased in two patients (0.2%). The incidence of notable increases more than 10 times the upper limit of normal in creatine kinase was similar with fluvastatin compared with placebo (0.3% in both).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Efficacy and safety of fluvastatin in hypertensive patients. An analysis of a clinical trial database. 829 42

Hypertension and diabetes appear to increase coronary heart disease risk in part by causing an abnormality in lipid metabolism. Most affected are patients with familial dyslipidemic hypertension (FDH) and noninsulin-dependent diabetes mellitus (NIDDM). The lipid disorders most often encountered in these patients are increased levels of triglycerides, very low-density lipoprotein (VLDL) cholesterol, and small, dense low-density lipoprotein (LDL) cholesterol, and low levels of high-density lipoprotein (HDL) cholesterol. These abnormalities appear to result from increased hepatic secretion of VLDL particles due to increased concentrations of free fatty acids and glucose, reduced VLDL clearance due to reduced activity of lipoprotein lipase, and reduced LDL clearance due to glycosylation of ligand proteins. Treatment of the dyslipidemia associated with FDH should follow the guidelines from the National Cholesterol Education Program. Treatment in men and women with NIDDM should be considered when LDL cholesterol levels are 130 mg/dl or above, triglyceride levels are 200 mg/dl or above, or non-HDL cholesterol levels are 160 mg/dl or greater. Aggressive lifestyle changes should be initiated first, including weight loss in obese patients, control of glucose levels in those with NIDDM, avoidance of antihypertensive drugs that may worsen lipid levels in patients with FDH, and eating a diet restricting saturated fat and cholesterol. Addition of lipid-altering drugs should be considered if such changes do not achieve effective lipid control. The agent should be tailored to the patient's lipid profile, in general by using bile acid resins, niacin, or reductase inhibitors to lower LDL cholesterol and gemfibrozil or niacin to lower triglycerides. Niacin should be avoided in patients with NIDDM.
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PMID:Understanding and treating dyslipidemia associated with noninsulin-dependent diabetes mellitus and hypertension. 836 60

Recent studies have demonstrated that the interconversion of active and inactive glucocorticoids plays a key role in determining the specificity of the mineralocorticoid receptor and controlling local tissue glucocorticoid receptor activation. Two distinct isoforms of the enzyme 11 beta-hydroxysteroid dehydrogenase (11 beta-HSD) have been identified. 11 beta-HSD1 is NADPH-dependent and at its major site of action (the liver) is a reductase, converting cortisone to cortisol (11-dehydrocorticosterone to corticosterone in the rat). 11 beta-HSD2 is NAD-dependent, is present in tissues such as the kidney and placenta, and converts cortisol to cortisone (corticosterone to 11-dehydrocorticosterone in the rat). Congenital or acquired deficiency of 11 beta-HSD2 produces the syndrome of apparent mineralocorticoid excess (SAME) in which cortisol gains access to the unprotected nonspecific mineralocorticoid receptor. The congenital deficiency is associated with mutations in the gene encoding the kidney isoform of 11 beta-HSD2; the acquired form results from inhibition of the enzyme by licorice, carbenoxolone, ACTH-dependent steroids in the ectopic ACTH syndrome, and possibly circulating inhibitors of the enzyme. This paper focuses on recent evidence, which suggest that low levels of placental 11 beta-HSD2 result in increased exposure of the fetus to maternal glucocorticoid and low birth weight. In animal studies using the rat we have shown that birth weight is correlated positively and placental weight negatively with the level of placental 11 beta-HSD. Thus animals with low birth weight and large placentae were those likely to be exposed to the highest level of maternal glucocorticoid. In man a similar relationship was found with birth weight being significantly correlated either with placental 11 beta-HSD activity or with the extent of cortisol inactivation by isolated perfused placental cotyledons. Administration of dexamethasone (which is poorly metabolized by placental 11 beta-HSD2) to pregnant rats resulted in decreased birth weight and the development of hypertension in the pups when adult. The same results were obtained when pregnant rats were given carbenoxolone, an inhibitor of placental 11 beta-HSD2. Low protein diet during pregnancy in the rat resulted in low birth weight of the pups, increased placental weight but decreased placental 11 beta-HSD activity, and adult hypertension. Thus increased glucocorticoid exposure of the fetus secondary to a failure of the normal inactivation of maternal glucocorticoid by the placental may be an important mechanism linking changes in the in utero environment and common adult diseases.
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PMID:11 beta-Hydroxysteroid dehydrogenases: key enzymes in determining tissue-specific glucocorticoid effects. 873 12

Treatment of hypercholesterolemia with HMG-CoA-reductase inhibitors has revolutionized medical intervention towards the prevention of coronary artery disease. There is a wide sprectrum of patients with diverse underlying clinical conditions that may benefit from treatment using these agents. These include patients with multiple risk factors, individuals following major vascular events, and those with special conditions that are associated with accelerated atherosclerosis. The latter include patients with severe, dominantly inherited hypercholesterolemia, patients with major organ dysfunction such as chronic renal failure, and individuals after transplantation. Multimodality intervention includes behavior modification and mechanical as well as pharmacological treatment. It is aimed at several important targets: cholesterol reduction, control of hypertension and diabetes, improvement of myocardial contractility, reduction of infarct size, and control of hemostasis. Most of these patients require multiple drugs, which may interact at the pharmacodynamic (efficacy and safety) as well as pharmacokinetic levels. These potential interactions should be considered while planning and implementing preventive measures for an individual as well as for the community. The beneficial effects and the potential hazardous interactions between HMG-CoA reductase inhibitors and other medications are presented and discussed using two models: heterozygous familial hypercholesterolemia and major organ transplantation. Although there is a partial overlap in the medications used for the treatment of these two conditions, some of them differ. The interaction between HMG-CoA reductase inhibitors and other cholesterol-lowering agents, mainly fibrates, is discussed in the first model summarizing data from controlled clinical trials. The interaction with cyclosporin A is presented using the second model. A potential benefit of fluvastatin, as compared with other currently available HMG-CoA reductase inhibitors, which may be related to its relatively short plasma half-life and low systemic exposure, is discussed.
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PMID:Targeted prevention of coronary artery disease: pharmacological considerations in multimodality treatment. 890 72

The type 1 and type 2 isoforms of human 11 beta-hydroxysteroid dehydrogenase (11 beta-HSD) play a crucial role, respectively, in modulating glucocorticoid and mineralocorticoid hormone action. Deficiency of the 11 beta-HSD2 isoform, as described in the syndrome of apparent mineralocorticoid excess and following liquorice (glycyrrhetinic acid) or carbenoxolone ingestion, results in hypertension in which cortisol acts as a potent mineralocorticoid. Several studies have addressed the effects of progesterone, glycyrrhetinic acid, and their derivatives on 11 beta-HSD activity, but these were largely undertaken before the characterization of the 11 beta-HSD isoforms. The aim of this study was to evaluate the localization of 11 beta-HSD2 in human kidney and to study the effects of progesterone, glycyrrhetinic acid, and their related compounds on stable transfectants of the human 11 beta-HSD isoforms. Using an in-house sheep antibody against human 11 beta-HSD2, immunoperoxidase studies localized 11 beta-HSD2 to renal cortical and medullary collecting ducts. Glomeruli, vascular structures, loops of Henle, and proximal tubules were all negative. Confocal laser microscopy studies indicated both a cytoplasmic and nuclear localization for the enzyme within renal collecting ducts. The nuclear staining, which was intranuclear and was not associated with the nuclear membrane, accounted for 40% of the total cellular 11 beta-HSD2 immunoreactivity. Kinetic analysis of 11 beta-HSD activity in fetal kidney 293 cells stably transfected with h11 beta-HSD1/pcDNA3 or 11 beta-HSD2/pCR3, indicated, respectively, low-affinity dehydrogenase/oxoreductase activity (Km for F, 1.8 microM; Km for E, 270 nM) and high-affinity dehydrogenase activity (Km for F, 190 nM). The reductase activity of 11 beta-HSD1 was inhibited by 11 alpha-hydroxyprogesterone > carbenoxolone = glycyrrhetinic acid = progesterone > 11 beta-hydroxyprogesterone. The dehydrogenase activity of 11 beta-HSD2 was inhibited 11 alpha-hydroxyprogesterone = 11 beta-hydroxyprogesterone > glycyrrhetinic acid > carbenoxolone = progesterone. 11 beta-HSD2, expressed in the renal collecting duct, serves to protect the mineralocorticoid receptor (MR) in an autocrine fashion. The demonstration of a nuclear localization for what was thought to be principally a microsomal enzyme suggests that interaction between the MR and its ligand (either aldosterone or cortisol) may be a nuclear rather than a cytoplasmic event. The inhibitory effects of progesterone, glycyrrhetinic acid, and related compounds on 11 beta-HSD1 and 2 were similar, and it remains to be seen what implication these findings have for 11 beta-HSD1 action in tissues such as the liver and gonad and renal 11 beta-HSD2 activity in relation to sodium homeostasis and blood pressure control.
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PMID:Human 11 beta-hydroxysteroid dehydrogenase: studies on the stably transfected isoforms and localization of the type 2 isozyme within renal tissue. 902 19

Short-chain dehydrogenase reductase (SDR) enzymes influence mammalian reproduction, hypertension, neoplasia, and digestion. The three-dimensional structures of two members of the SDR family reveal the position of the conserved catalytic triad, a possible mechanism of keto-hydroxyl interconversion, the molecular mechanism of inhibition, and the basis for selectivity. Glycyrrhizic acid, the active ingredient in licorice, and its metabolite carbenoxolone are potent inhibitors of bacterial 3 alpha, 20 beta-hydroxysteroid dehydrogenase (3 alpha, 20 beta-HSD). The three-dimensional structure of the 3 alpha,20 beta-HSD carbenoxolone complex unequivocally verifies the postulated active site of the enzyme, shows that inhibition is a result of direct competition with the substrate for binding, and provides a plausible model for the mechanism of inhibition of 11 beta-hydroxysteroid dehydrogenase and 15-hydroxyprostaglandin dehydrogenase by carbenoxolone. The structure of human 17 beta-hydroxysteroid dehydrogenase type 1 (17 beta-HSD) suggests the details of binding of estrone and 17 beta-estradiol in the active site of the enzyme and the possible roles of various amino acids in the catalytic cleft. The SDR family includes over 50 proteins from human, mammalian, insect, and bacterial sources. Only five residues are conserved in all members of the family, including the YXXXK sequence. X-ray crystal structures of five members of the family have been completed. When the alpha-carbon backbone of the cofactor binding domains of the five structures are superimposed, the conserved residues are at the core of the structure and in the cofactor binding domain, but not in the substrate binding pocket.
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PMID:Structure and function of steroid dehydrogenases involved in hypertension, fertility, and cancer. 902 22

Whereas aldosterone is normally a much stronger mineralocorticoid than cortisol in vivo, mineralocorticoid receptors have identical in vitro affinities for these hormones. The in vivo specificity of the receptors is, at least in part, the result of activity of 11-HSD, an enzyme located in most mineralocorticoid target tissues that converts cortisol to cortisone. Cortisone is not a ligand for the receptor, whereas aldosterone is not a substrate of the enzyme. The syndrome of AME is a rare form of juvenile hypertension in which 11-HSD is defective. This deficiency allows mineralocorticoid receptors to be occupied by cortisol, leading to hypertension, because plasma concentrations of cortisol are much higher than those of aldosterone. Licorice, which contains 11-HSD inhibitors, causes a similar syndrome. There are two known isozymes of 11-HSD. The liver or type I isozyme is expressed at high levels in the liver, has a relatively low affinity for steroids (micromolar Km), catalyzes both dehydrogenation and the reverse reductase reaction, and utilizes NADP+ or NADPH as cofactors. The kidney or type 2 isozyme is expressed at high levels in the kidney and placenta, has a high affinity (nanomolar Km) for steroids, catalyzes only dehydrogenation, and utilizes NAD+ as a cofactor. Mutations in the HSD11B2 (HSD11K) gene encoding the kidney isozyme of 11-HSD have been detected in all kindreds with AME studied thus far. This gene represents a candidate locus for the common, "essential" form of hypertension.
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PMID:11 beta-Hydroxysteroid dehydrogenase and the syndrome of apparent mineralocorticoid excess. 903 89

Mild hyperhomocysteinemia has been identified as a risk factor for arterial disease and for venous thrombosis. Individuals homozygous for the thermolabile variant of the methylene tetrahydrofolate reductase gene (MTHFR) which results from a common mutation Ala677-->Val and is found in 5-15% of the general population, have significantly elevated plasma homocysteine levels and may account for one of the genetic risk factors in vascular disease. We have analyzed the prevalence of MTHFR-T homozygotes in patients with arterial disease or venous thrombosis. We studied 191 patients with arterial disease and 127 individuals with venous thrombosis and compared with 296 unmatched controls. The results showed that there was a high prevalence of homozygotes for the mutated MTHFR-T allele among a group of patients with arterial disease (19%) in the absence of hyperlipoproteinemia, hypertension, and diabetes mellitus when compared to controls (4%), odds ratio of 5.52 (95% C.I., 2.27 to 13.51). The prevalence of homozygotes among patients with venous thrombosis was 11%, odds ratio of 2l93 (95% C.I., 1.23 to 7.01). The risk of venous thrombosis remained high, odds ratio of 2.63, even after we excluded 27 patients with hereditary thrombophilia (e.g. factor V Leiden, dysfibrinogenemia, deficiency of protein C, protein S, antithrombin III, or factor XII) from the 127 overall cases with venous thrombosis. These data support the hypothesis that being a homozygote for the MTHFR-T is a risk factor for the development of arterial disease and also for venous thrombosis.
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PMID:The mutation Ala677-->Val in the methylene tetrahydrofolate reductase gene: a risk factor for arterial disease and venous thrombosis. 918 84

Cardiac allograft vasculopathy (CAV) remains a troublesome long-term complication of heart transplantation. It is manifested by a unique and unusually accelerated form of coronary disease affecting both intramural and epicardial coronary arteries and veins.CAV is characterized by vascular injury induced by a variety of noxious stimuli, including the immune system response to the allograft, ischemia-reperfusion injury, viral infection, immunosuppressive drugs, and classic risk factors such as hyperlipidemia, insulin resistance, and hypertension. The obstructive vascular lesions are thought to progress through repetitive endothelial injury followed by repair response. The role of major histocompatibility complex donor-recipient differences in the pathogenesis of CAV has not yet been completely elucidated. Intracoronary ultrasound studies reveal a dual morphology with donor-transmitted or de novo focal, noncircumferential plaques in proximal segments and/or a diffuse, concentric pattern observed in distal segments. A lack of correlation between microvascular and epicardial vessel disease suggests discordant manifestations and progression of CAV. Apoptosis and loss of functional vascular remodeling have to be considered as important mediators of clinically relevant CAV. Strategies for blocking T-cell costimulation and expression of adhesion molecules may help prevent chronic rejection in clinical transplantation. 3-Hydroxy-3-methylglutaryl coenzyme A reductase inhibitors and antiproliferative drugs may slow progression of CAV by various effects. Methods to augment endogenous nitric oxide bioavailability as well as newer immunosuppressive regimens may be protective. Balloon angioplasty has a limited role in the treatment of focal lesions. Experiences with coronary stenting, coronary artery bypass grafting, and transmyocardial laser revascularization are limited. Retransplantation has a worse outcome than initial transplantation.
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PMID:Cardiac allograft vasculopathy: a review. 932

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