Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0085580 (essential hypertension)
 14,686 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Both Na+/Li+ countertransport and electrochemical proton gradient (delta mu(H+))-induced Na+ and H+ fluxes are increased in erythrocytes from patients with essential hypertension. It was assumed that these abnormalities are related to ubiquitous (housekeeping) forms of the Na+/H+ exchanger (NHE-1). To examine this hypothesis, we compared kinetic and regulatory properties of erythrocyte Na+/Li+ countertransport and delta mu(H+)-induced Na+ and H+ fluxes with data obtained for cloned isoforms of the Na+/H+ exchanger. In human erythrocytes, Na+/Li+ countertransport exhibited a hyperbolic dependence on [Na+]0 with a K0.5 of approximately 30 to 40 mmol/L. The activity of this carrier was increased by two-fold in the fraction of erythrocytes enriched with the old cells, was inhibited by 0.1 mmol/L phloretin, and was insensitive to both 1 mmol/L amiloride and ATP depletion. In contrast, delta mu(H+)-induced 22Na influx was exponentially increased at [Na+]0 > 60 mmol/L, was insensitive to phloretin, was partly decreased by both 1 mmol/L amiloride and ATP depletion, and was the same in total erythrocytes and in the old cells. The values of Na+/Li+ countertransport and delta mu(H+)-induced Na+ influx in erythrocytes from different species were not correlating and their ratio in human, rat, and rabbit erythrocytes was 10:1:170 and 1:5:1 for Na+/ Li+ countertransport and delta mu(H+)-induced Na+ influx, respectively. In contrast to the majority of nonepithelial cells and cells transfected with an ubiquitous isoform of Na+/H+ exchanger, both delta mu(H+)-induced Na+ influx and Na+/Li+ countertransport in human erythrocytes were completely insensitive to ethylisopropyl amiloride (20 micromol/L) and cell shrinkage. Thus, our data strongly suggest that human erythrocyte Na+/Li+ countertransport and delta mu(H+)-induced Na+/H+ exchange are mediated by the distinct transporters. Moreover, because the properties of these erythrocyte transporters and NHE-1 are different, it complicates the use of erythrocytes for the identification of the mechanism for activating the ubiquitous form of Na+/H+ exchanger in primary hypertension.
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PMID:Can we use erythrocytes for the study of the activity of the ubiquitous Na+/H+ exchanger (NHE-1) in essential hypertension? 968 37

Potassium channels are transmembrane proteins that allow this ion to diffuse through the plasma membrane. By participating in the generation of membrane potential they regulate intracellular calcium levels and vascular smooth muscle contraction. Voltage-gated and ATP-gated potassium channels have been described in vessel smooth muscle. Minoxidil and diazoxide vasodilate by opening ATP-gated potassium channels. Soon other K-ATP channel openers will be available. It has been suggested that hypoxic vasodilatation and shock are due to excessive activation of potassium channels. Mutations in potassium channels have been implied in the pathogenesis of essential hypertension.
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PMID:[Blood pressure regulation by potassium channels]. 981 9

The contents of adenine nucleotides (ATP, ADP, AMP), phosphocreatine (PCr) and creatine (Cr) in the heart, skeletal muscle, liver and spleen in spontaneously hypertensive (SHR) and normotensive (WKY) rats. The ATP/ADP ratio in cardiac tissue was lower in SHR compared with WKY, while myocardial contents of adenine nucleotides, PCr and Cr did not differ significantly between the groups. A lower ATP/ADP ratio in the skeletal muscle SHR of was accompanied by a reduction of PCr content comparing with these indices in WKY rats. The liver and spleen of SHR exhibited lower ATP contents and higher ADP and AMP levels compared with those ones in WKY rats, despite of the close values of adenine nucleotide pools (sigma AN = ATP + ADP + AMP). This redistribution of tissue adenine nucleotides was corresponded to lower energy charges (EC = (ATP + 0.5 ADP)/sigma AN) and ATP/ADP ratios in SHR group. The reduction of the energy state of tissues in SHR rats increased in the following rank: heart > skeletal muscle > liver > spleen, thus, reflecting progressive decrease of intensity of oxidative metabolism. The results suggest changes in the balance of rates of ATP formation and hydrolysis occur at the system level in primary hypertension. Probably, consequences of such rearrangement in energy metabolism are functional disturbances of plasma membrane and sacroplasmic reticulum well-documented in a number of experimental and clinical studies.
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PMID:[Changes in the energy state of tissues in spontaneously hypertensive rats]. 1051 1

Essential Hypertension (EH) is correlated with a metabolic disturbance characterized by insulin resistance (IR). In this study, there were observed in 47 subjects with EH and 30 subjects with normal blood pressure. Serum levels of insulin-like growth factor-1 (IGF-1), serum levels of growth hormone (GH), the activity of erythrocyte insulin receptors (EIR), and ATP levels in erythrocytes, the insulin sensitivity index (ISI) was used to study the correlative factors of essential hypertension. 1. Among patients with EH, ISI, GH, and low-affinity insulin binding sites of EIRs (RT2) were found to be in significantly lower amounts, IGF-1 levels and the KD2 of the erythrocyte insulin receptors were noted to be significantly higher. Compared with the control group, there was a marked difference between EH group and the control group. However, no statistical difference was observed between the hypertensive group and the group with normal blood pressure as regards erythrocyte ATP levels, high-affinity insulin binding sites of EIRs (RT1), and the KD1 of EIRs. 2. In the hypertensive group, the ISI was negatively correlated with mean arterial blood pressure (MBP), a family history of hypertension, the body mass index (BMI), the waist-hip ratio (WHR) and IGF-1 levels (r=-0.614delta, -0.354**, -0.386**, -0.472**, -0.298*, delta p < 0.001, **p < 0.01, *p < 0.05), were positively correlated with RT2 and GH levels (r=0.301**, 0.275*, **p < 0.01, *p < 0.05). There were no statistically significant differences between ISI and age, sex, smoking history, drinking, RT1, KD1, and ATP levels in erythrocytes. 3. The ISI was used as the dependent variable in multiple linear stepwise regression analysis. MBP (X1), a family history of EH (X2), WHR (X3), GH (X4), IGF-1 (X5), RT2 (X6), and the body mass index (X7) was used as independent variables. X1, X2, X3, X5, X6, and X7 were used in the equations. The results indicate that patients with EH also tend to have IR. We suggest that MBP, a family history of hypertension, BMI, WHR, IGF-1, and RT2 might be independent factors affecting IR in cases of essential hypertension.
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PMID:Correlative factors of insulin resistance in essential hypertension. 1082 Nov 37

Acetyl-CoA-Synthetase (ACS) is involved in the production of acetate, a major metabolite in numerous organisms. There are two forms of this enzyme: ADP-forming ACS and ATP-forming ACS. We focus mainly on the AMP-forming ACS gene, which is relatively well conserved in eubacteria, archeaebacteria, and eukaryotes. BLAST searches in databases showed 30 protein sequences significantly related to the ACS. Most of these sequences were identified as ACS but three of them, belonging to the mammalian species, were annotated as another gene named: the SA gene, which is involved in the essential hypertension. The ACS and SA genes probably derived from a duplication of an ancestral gene but have acquired different functions. Six conserved regions of the ACS protein were defined across the three domains of life. While the precise function of the conserved regions remains unknown, they are probably involved in the enzymatic activity. Among eukaryotes, we found a high variability with respect to the number and the position of introns. However, some positions are conserved between fungi and a nematode. A maximum likelihood tree based upon the conserved regions showed that all sequences except the one from B. subtilis, belong to two basic groups: one the SA-like group including sequences from Archaeoglobus fulgidus and Streptomyces coelicolor, and second, the ACS group. The later can be further divided in two parts: a prokaryotic one including eubacteria and an archaebacterium, and a eukaryotic group within which two proteobacterial sequences branch including ACS from the alpha-proteobacterium Rhodobacter capsulatus. Within the eukaryotic group, bootstrap support is very low, but overall the data are consistent with the view that eukaryotes acquired their ACS gene from the ancestors of mitochondria. The localization of this enzyme in eukaryotic mitochondria is the additional evidence in favor of this interpretation.
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PMID:Molecular evolution of the AMP-forming Acetyl-CoA synthetase. 1125 12

The author proceeds that increased arterial blood (BP) pressure, reflecting the shift of the threshold blood pressure controlling system, is conditioned by underlying energy deficiency at the cellular level, caused by a decrease of the mitochondrial energy generating function. Elevation of systemic BP in hyperthyroidism resultant from oxidation-phosphorylation uncoupling, leading to decrease of ATP production by mitochondria, is an example of energy dependence of the hypertension phenomenon. In primary hypertension (essential hypertension in humans and spontaneous hypertension in rats) one can speak about genetically determined characteristics of cell membranes (so-called membrane defect) leading to insufficient regulation of intracellular calcium and increased concentrations of free calcium in the cytosol under physiological actions on cell calcium homeostasis mechanisms. Elevation of BP mediated by increased efferent sympathetic activity occurs as far as the excess of the cytosolic calcium accumulates in the mitochondria and their energy generating function decreases, which results in alteration of the ion transporting function of cell membranes. Hence, increased systemic BP in primary hypertension should be considered as an inherent feature of circulation corresponding to altered cell energetics.
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PMID:[The role of mitochondrial calcium overload and energy deficiency in pathogenesis of arterial hypertension]. 1145 50

Mendelian forms of hypertension have delivered a treasure trove of novel genes. To date, the molecular mechanisms of five such syndromes have been largely clarified, including glucocorticoid-remediable aldosteronism, Liddle's syndrome, apparent mineralocorticoid excess, an activating mutation of the mineralocorticoid receptor, and pseudohypoaldosteronism type 2. Each of these conditions features salt sensitivity with increased sodium and volume reabsorption by the kidney and low plasma renin activity. None of the gene loci for these syndromes has been convincingly linked to hypertension in the general population. We are investigating kindreds who have autosomal-dominant hypertension and brachydactyly. Affected persons invariably have both anomalies. The hypertension is severe and results in death at about age 50 years from stroke. The condition resembles essential hypertension, because renin, aldosterone, and norepinephrine responses are normal and no salt sensitivity is present. The response to antihypertensive drugs is general. Another feature is diminished baroreflex sensitivity with markedly impaired blood pressure buffering. Furthermore, the ventrolateral medulla may be compromised in these patients, because neurovascular anomalies are a regular finding. We mapped the gene(s) for this disease to chromosome 12p and narrowed the chromosomal region by studying more affected families. Interestingly, the same locus was recently mapped in Chinese families with essential hypertension. Our 3-centimorgan region contains genes encoding a phosphodiesterase, an ATP-dependent potassium channel, and its regulator the sulfonylurea receptor 2. Screening of the coding regions revealed that none of these candidate genes harbor obvious mutations; however, other genetic mechanisms may nevertheless compromise their function. Our study underscores the importance of regulatory physiology to the understanding of a complex genetic syndrome.
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PMID:Mendelian hypertension with brachydactyly as a molecular genetic lesson in regulatory physiology. 1295 13

Metabolic syndrome represents a cluster of clinical, biochemical and humoral abnormalities associated with impaired insulin action in glucose metabolism. In the literature also the term syndrome of insulin resistance, dysmetabolic syndrome X, Reaven syndrome or Kaplans dead quartet can be found. Hyperinsulinaemia, central obesity, essential hypertension, dyslipidaemia, impaired glucose homeostasis or type 2 diabetes, hyperuricaemia, hypercoagulable state, endothelial dysfunction and increased markers of inflammation such as C-reactive protein, selectines, adhesion molecules, pro-inflammatory cytokines are the typical components of metabolic syndrome increasing the risk of cardiovascular complications. List of currently recognized clinical and biochemical manifestations continues to expand and include also non-alcoholic steatohepatitis, polycystic ovaric syndrome (PCOS), hyperhomocysteinaemia and others. No standard definition of metabolic syndrome has been routinely used. The WHO initially proposed a definition of metabolic syndrome in 1998, and more recently NCEP-ATP III provided a new working definition in 2001, which is more suitable for clinical practice. Prevalence of metabolic syndrome is very high, about 25-30% in Caucasians, depending on diagnostic criteria used. The clinical significance of metabolic syndrome is augmented by its association with increased and accelerated atherosclerosis. Whether IR predicts cardiovascular disease (CVD) independently of diabetes and other CVD risk factors is still a matter of controversy. Recently there is a growing evidence that metabolic syndrome increases also the risk of all-cause mortality and risk of certain tumors.
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PMID:[The metabolic syndrome]. 1504 Jan 52

There are accumulated evidences on existence of an imbalance between energy production and consumption in tissues in primary hypertension resulting in insufficient compensation of energy and its deficiency in cells (human essential hypertension, spontaneous hypertension in rats, SHR). An origin of these abnormalities resides in an alteration of cell mitochondrion ATP-synthetic function which ground is calcium overload of mitochondria due to increased cytosolic calcium redundantly entering into mitochondria and development of insufficiency of mPT pore removing calcium from matrix of the organells. There is an energy production deficiency in brain tissue of individuals with primary hypertension that is not initially caused by alteration of cerebral blood circulation of ischemic type. The mentioned energy abnormality is determined by decreased ability of brain mitochondria to synthesize ATP as a result of their calcium overload due to altered cell calcium handling in hypertension (so called membrane defect). In these conditions the registered normal or insignificantly changed cerebral blood flow in primary hypertension may be a result of systemic blood pressure increase in response to energy deficiency in brain tissue. Mechanisms mediating development of systemic hypertension include as the most important activation of vasomtor centers of brain stem. Other systems influencing vascular flow and peripheral resistance also contribute. Among those redundant (under conditions of calcium overload) production of oxidative radicals by mitochondria canceling vasorelaxing effect of NO should be specifically mentioned. The structural remodeling of peripheral circulation including rarefaction of capillary network provides for irreversibility of hypertension.
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PMID:[On the role of insufficient mitochondrial energy production in primary hypertension: the neurogenic constitutive of the pathogenesis]. 1521 46

The WNK kinases are a small group of serine/threonine kinases with unique catalytic domains that lack the lysine residue used in other kinases to co-ordinate ATP (hence, With No K [WNK]). Their closest homologues are found within the mitogen-activated protein kinase (MAPK) pathway suggesting a role in signalling. Two WNK isoforms, WNK1 and WNK4, have been identified as the disease genes for a rare monogenic hypertension syndrome (Gordon's syndrome or pseudohypoaldosteronism type 2 [PHA2]) implicating them in salt homeostasis by the kidney. This is supported by recent data showing widespread expression of WNK1 and WNK4 in mammalian transporting epithelia. Within the kidney, WNKs probably regulate the surface expression of several proteins involved in ion transport, including the sodium-chloride cotransporter (NCCT) and the potassium channel renal outer medullary potassium channel (ROMK), based on co-expression studies in Xenopus oocytes. WNKs, especially WNK4, have been suggested as candidate genes for essential hypertension itself, but evidence for this is lacking. Some of the effects of the WNKs are independent of their kinase function, suggesting that they are dependent on specific protein-protein interactions. It seems likely that the WNKs are part of much larger protein scaffolds in cells and have effects in cells beyond ion transport. However, because of their effect on expression of the NCCT they are attractive drug targets for the development of novel antihypertensive agents. These agents could potentially offer the efficacy of a thiazide diuretic, but without the metabolic side effects usually seen with this class of antihypertensive therapy.
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PMID:WNK kinases and the control of blood pressure. 1586 21


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