Angiotensin I-converting Enzyme Levels Research Articles

Carriers of Heterozygous Loss-of-Function ACE Mutations Are at Risk for Alzheimer's Disease.

We hypothesized that subjects with heterozygous loss-of-function (LoF) ACE mutations are at risk for Alzheimer's disease because amyloid Aβ42, a primary component of the protein aggregates that accumulate in the brains of AD patients, is cleaved by ACE (angiotensin I-converting enzyme). Thus, decreased ACE activity in the brain, either due to genetic mutation or the effects of ACE inhibitors, could be a risk factor for AD. To explore this hypothesis in the current study, existing SNP databases were analyzed for LoF ACE mutations using four predicting tools, including PolyPhen-2, and compared with the topology of known ACE mutations already associated with AD. The combined frequency of >400 of these LoF-damaging ACE mutations in the general population is quite significant-up to 5%-comparable to the frequency of AD in the population > 70 y.o., which indicates that the contribution of low ACE in the development of AD could be under appreciated. Our analysis suggests several mechanisms by which ACE mutations may be associated with Alzheimer's disease. Systematic analysis of blood ACE levels in patients with all ACE mutations is likely to have clinical significance because available sequencing data will help detect persons with increased risk of late-onset Alzheimer's disease. Patients with transport-deficient ACE mutations (about 20% of damaging ACE mutations) may benefit from preventive or therapeutic treatment with a combination of chemical and pharmacological (e.g., centrally acting ACE inhibitors) chaperones and proteosome inhibitors to restore impaired surface ACE expression, as was shown previously by our group for another transport-deficient ACE mutation-Q1069R.

Angiotensin I-Converting Enzyme Inhibitory Activity of Two Peptides Derived from In Vitro Digestion Products of Pork Sausage with Partial Substitution of NaCl by KCl.

This study aimed to identify angiotensin I-converting enzyme (ACE) from in vitro digestion products of pork sausage with partial substitution of NaCl by KCl (PSRK). Peptides from in vitro digestion products of PSRK were identified through liquid chromatography with tandem mass spectrometry analysis coupled with de novo sequencing. Subsequently, the ACE inhibitory peptides LIVGFPAYGH and IVGFPAYGH were screened based on PeptideRanker, in silico absorption, molecular docking, and the determination of ACE inhibitory activity. In addition, the ACE inhibitory peptides LIVGFPAYGH and IVGFPAYGH were mixed-type inhibitors; these peptides' ACE inhibitory activities were expressed as the 50% inhibitory concentration (IC50) values in vitro, which were 196.16 and 150.88 μM, respectively. After 2 h of incubation, LIVGFPAYGH and IVGFPAYGH could be transported through Caco-2 cell monolayers with paracellular passive diffusion. Furthermore, LIVGFPAYGH and IVGFPAYGH significantly increased the levels of ACE2 and nitric oxide while decreasing the levels of ACE, angiotensin II, and endothelin-1 in Ang I-treated human umbilical vein endothelial cells, indicating the ACE inhibitory effect of LIVGFPAYGH and IVGFPAYGH. In summary, LIVGFPAYGH and IVGFPAYGH from PSRK can be used as functional foods with antihypertensive activity.

Synergistic cardioprotective ability of co-administration of Moringa supplemented diets and acarbose in diabetic cardiomyopathy involves attenuation of cholinergic, purinergic, monoaminergic, renin-angiotensin system, and antioxidant pathways.

One of the major complications of diabetes mellitus (DM) is diabetic cardiomyopathy (DCM) due to the multifaceted therapy involved. Here, we evaluated the combinatorial effect of Moringa leaf (ML) and seed (MS) supplemented diets plus acarbose (ACA) on cardiac acetylcholinesterase (AChE), adenosine triphosphatase (ATPase), adenosine deaminase (ADA), monoamine oxidase (MAO), arginase, angiotensin-I converting enzyme (ACE), and lactate dehydrogenase (LDH) activities, thiobarbituric acid reactive species (TBARS), and thiols levels. The diets and ACA (25 mg/kg) were administered for 14 days. The fasting blood glucose level (FBGL), cardiac AChE, ATPase, ADA, MAO, arginase, ACE, LDH activities, and TBARS and thiol levels were determined. Relative to the normal rats, the biomarkers were significantly increased in DM rats but were suppressed significantly in the diets plus ACA-treated rats while improving antioxidant status, with the 4% Moringa plus ACA proving outstanding compared to individual ML/MS and ACA. In addition, ML-supplemented diets with/without ACA had better effects compared to MS with/without ACA, respectively. In conclusion, the combination of ML/MS supplemented diets and ACA synergistically modulates the tested biochemicals. However, the effect on blood vessels and the nerves that control the heart, stiffness of left ventricular (LV) hypertrophy, fibrosis, cell signaling abnormalities, related gene expression, clinical trials, and echocardiology studies should be further investigated to affirm this claim. PRACTICAL APPLICATIONS: Moringa oleifera has been a vocal appetite in mitigating cardiovascular disease induced by diabetes, but the formulation of a medicinal diet as an ameliorative route of attention to the pathology is fairly addressed, not talking of its combination with the synthetic antidiabetic drug, such as ACA. Based on this experiment, it is imperative to explore such an idea. This research shows that co-administration of moringa leaf/seed formulated diets plus ACA exhibits a synergistic effect in DCM management. However, further research is needed in this field of experiment.

Novel ACE mutations mimicking sarcoidosis by increasing blood ACE levels

An elevated blood angiotensin I-converting enzyme (ACE) supports diagnosis of sarcoidosis and Gaucher disease. However, some ACE mutations increase ACE shedding, and patients with these mutations are therefore at risk of being incorrectly diagnosed with sarcoidosis because of elevated serum ACE levels. We applied a novel approach called "ACE phenotyping" to identify possible ACE mutations in 3 pulmonary clinic patients that had suspected sarcoidosis based on elevated blood ACE levels. Conformational fingerprinting of ACE indicated that these mutations may be localized in the stalk region of the protein and these were confirmed by whole exome sequencing. Index patient 1 (IP1) had a mutation (P1199L) that had been previously identified, while the other 2 patients had novel ACE mutations. IP2 had 2 mutations, T887M and N1196K (eliminating a putative glycosylation site), while IP3 had a stop codon mutation Q1124X (eliminating the transmembrane anchor). We also performed a comprehensive analysis of the existing database of all ACE mutations to estimate the proportion of mutations increasing ACE shedding. The frequency of ACE mutations resulting in increased blood ACE levels may be much higher than previously estimated. ACE phenotyping, together with whole exome sequencing, is a diagnostic approach that could prevent unnecessary invasive and/or costly diagnostic procedures, or potentially harmful treatment for patients misdiagnosed on the basis of elevated blood ACE levels.

Modulatory effects of stonebreaker (Phyllanthus amarus) and bitter gourd (Momordica charantia) on enzymes linked with cardiac function in heart tissue of doxorubicin-stressed rats

Doxorubicin (DOX) has been linked with impairment in cardiovascular function and redox balance. In the present study, the effect of Phyllanthus amarus (PA) and Momordica charantia (MC) leaves on some biomolecules [Angiotensin-I converting enzyme (ACE), arginase, acetylcholinesterase (AChE), adenosine deaminase (ADA), lactate dehydrogenase (LDH)] and antioxidant [catalase (CAT), superoxide dismutase (SOD), glutathione (GSH) and malondialdehyde (MDA)] linked with cardiac function in DOX-stressed rats was evaluated. Animals were grouped and pretreated with PA and MC leaf extracts at different doses (200 and 400 mg/kg/bwt orally), while DOX (15 mg/kg/bwt) was administered intraperitoneally on the last day of the experiment. Result revealed an increase of ACE, arginase, AChE, ADA, LDH activities and MDA level as well as a significant reduction in CAT and SOD activities, and GSH level in the rats treated with DOX compared to the control. However, these were significantly mitigated in the rats pretreated with PA and MC dose dependently. Chemical characterization of the leaf extracts via high performance liquid chromatography revealed the presence of some phenolic compounds which included kaempferol, catechin, epicatechin, ellagic acid, gallic acid quercetin, isoquercitrin and rutin. These findings revealed a significant improvement in redox imbalance and other biomolecules associated with cardiac function, which was altered by DOX. This improvement could be linked to the presence of cardioprotective agents present in PA and MC, thereby making these plants therapeutic agents for the treatment of cardiovascular complications associated with drugs such as DOX.

Associations of ACE I/D polymorphism with the levels of ACE, kallikrein, angiotensin II and interleukin-6 in STEMI patients

This study aimed to compare the plasma levels of angiotensin-I converting enzyme (ACE), Angiotensin II (AngII), kallikrein (KLK1) and interleukin-6 (IL-6) in ST segment elevation myocardial infarction (STEMI) patients with different ACE Insertion/deletion (I/D) polymorphisms in a Chinese population. The ACE genotypes were determined in the 199 STEMI patients and 216 control subjects. STEMI patients were divided into three groups based on the ACE genotypes. Single polymerase chain reaction (PCR) was performed to characterize ACE I/D polymorphisms. Plasma levels of ACE, AngII, KLK1 and IL-6 were measured by enzyme-linked immunosorbent assay (ELISA). We found that the DD or ID genotype was significantly independently associated with high ACE (OR = 4.697; 95% CI = 1.927–11.339), KLK1 (3.339; 1.383–8.063) and IL-6 levels (OR = 2.10; 1.025–4.327) in STEMI patients. However, there was no statistical significance between the ACE I/D polymorphism and AngII plasma levels whether in univariate or multivariate logistic regression. Additionally, we detected a significantly positive correlation between plasma KLK1 levels and IL-6 levels in STEMI patients (r = 0.584, P < 0.001). The study showed high levels of ACE, KLK1 and IL-6 were detected when the D allele was present, but AngII plasma levels was not influenced by the ACE I/D polymorphism.

Associations Between Genetic Polymorphisms in the VEGFA, ACE, and SOD2 Genes and Susceptibility to Diabetic Nephropathy in the Han Chinese.

Objective: To investigate the association between polymorphisms in the rs2010963 and rs69947 loci of the vascular endothelial growth factor A (VEGFA) gene; the rs4646994 locus of the angiotensin I converting enzyme (ACE) gene; and the rs4880 locus of the superoxide dismutase 2 (SOD2) gene with genetic susceptibility to type 2 diabetic nephropathy (T2DN) in the Chinese Han population. Methods: A total of 650 Chinese Han patients with T2DN and 580 non-nephropathy patients with type 2 diabetes were enrolled in this study. Sanger sequencing was used to detect the genotypes of the rs2010963 and rs69947 loci within VEGFA, the rs4646994 locus of for the ACE gene, and the rs4880 locus of the SOD2 gene in all subjects. Enzyme-linked immunosorbent assays were used to detect VEGFA, ACE, and SOD2 levels in serum. Results: The risk of T2DN was significantly increased (odds ratio [OR] = 1.15, confidence interval [95% CI]: 1.03-1.30) in patients with the GC/CC genotypes compared to those with the GG genotype at the rs2010963 locus of the VEGFA gene under the dominant model of inheritance. Similarly, the risk of T2DN was significantly increased (OR = 1.17, 95% CI: 1.05-1.31) in patients with the CA/AA genotypes compared to those with the CC genotype at the rs69947 locus of the VEGFA gene under the dominant model of inheritance. In addition, the risk of T2DN was increased (OR = 1.57, 95% CI: 1.37-1.74) in patients with the AA genotype compared to the CC/CA genotypes under the recessive model of inheritance. The risk of T2DN was also significantly increased (OR = 1.54, 95% CI: 1.24-1.97) in patients with the ID/DD genotypes compared to those with the II genotype at the rs4646994 locus of the ACE gene under the dominant model; and (OR = 1.41, 95% CI: 1.26-1.57) for DD genotype compared to the II/ID genotypes under the recessive model. We also found the risk of T2DN was significantly increased (OR = 1.25, 95% CI: 1.11-1.39) under the dominant model in patients with the TC/CC genotypes compared to the TT genotype, and for the CC genotype (compared to the TT/TC genotype) (OR = 1.45, 95% CI: 1.18-1.66) under the recessive model at the rs4880 locus of the SOD2 gene rs4880. The haplotypes GAC (OR = 1.17, 95% CI: 1.04-1.29), CAT (OR = 1.12, 95% CI: 1.03-1.60), and CAC (OR = 1.13, 95% CI: 1.01-1.24) constructed from VEGFA gene rs2010963 and rs69947 loci, and the SOD2 gene rs4880 locus were associated with a higher risk for T2DN. Finally, we found that VEGFA protein levels from subjects with the rs2010963 GG genotype and the rs69947 CC genotype were higher in both case groups and the control group than in subjects with rs2010963 GA/AA genotypes and rs69947 CA/AA genotypes, respectively (p < 0.05). The ACE protein levels for variants at the rs4646994 locus showed that the case group and control group subjects with the DD genotype had the highest levels, followed by the ID genotype and the II genotype (p < 0.05). Conclusion: Genetic variation in the VEGFA gene at the rs2010963 and rs69947 loci, the ACE gene at the rs4646994 locus, and the SOD2 gene at the rs4880 locus may increase the risk of developing T2DN.

Foxd1 is an upstream regulator of the renin-angiotensin system during metanephric kidney development.

BackgroundWe tested the hypothesis that Foxd1, a transcription factor essential for normal kidney development, is an upstream regulator of the renin-angiotensin system (RAS) during ureteric bud (UB)-branching morphogenesis.MethodsUB branching, RAS gene, and protein expression were studied in embryonic mouse kidneys. RAS mRNA expression was studied in mesenchymal MK4 cells.ResultsThe number of UB tips was reduced in Foxd1-/- compared with that in Foxd1+/+ metanephroi on embryonic day E12.5 (14±2.1 vs. 28±1.3, P<0.05). Quantitative real-time reverse-transcription polymerase chain reaction (qRT-PCR) demonstrated that renin, angiotensin I-converting enzyme (ACE), and angiotensin (Ang) II receptor type 1 (AT1R) mRNA levels were decreased in Foxd1-/- compared with those in Foxd1+/+ E14.5 metanephroi. Western blot analysis and immunohistochemistry showed decreased expression of AGT and renin proteins in Foxd1-/- metanephroi compared with that in Foxd1+/+ metanephroi. Foxd1 overexpression in mesenchymal MK4 cells in vitro increased renin, AGT, ACE, and AT1R mRNA levels. Exogenous Ang II stimulated UB branching equally in whole intact E12.5 Foxd1-/- and Foxd1+/+ metanephroi grown ex vivo (+364±21% vs. +336±18%, P=0.42).ConclusionWe conclude that Foxd1 is an upstream positive regulator of RAS during early metanephric development and propose that the cross-talk between Foxd1 and RAS is essential in UB-branching morphogenesis.

Lysozyme and bilirubin bind to ACE and regulate its conformation and shedding.

Angiotensin I-converting enzyme (ACE) hydrolyzes numerous peptides and is a critical participant in blood pressure regulation and vascular remodeling. Elevated tissue ACE levels are associated with increased risk for cardiovascular and respiratory disorders. Blood ACE concentrations are determined by proteolytic cleavage of ACE from the endothelial cell surface, a process that remains incompletely understood. In this study, we identified a novel ACE gene mutation (Arg532Trp substitution in the N domain of somatic ACE) that increases blood ACE activity 7-fold and interrogated the mechanism by which this mutation significantly increases blood ACE levels. We hypothesized that this ACE mutation disrupts the binding site for blood components which may stabilize ACE conformation and diminish ACE shedding. We identified the ACE-binding protein in the blood as lysozyme and also a Low Molecular Weight (LMW) ACE effector, bilirubin, which act in concert to regulate ACE conformation and thereby influence ACE shedding. These results provide mechanistic insight into the elevated blood level of ACE observed in patients on ACE inhibitor therapy and elevated blood lysozyme and ACE levels in sarcoidosis patients.

Importance of ACE polymorphisms for endurance performance

The skeletal muscle renin-angiotensin system (RAS) plays an important role in exercise metabolism. A functional insertion (I)/deletion (D) polymorphism in the angiotensin I- converting enzyme (ACE) gene (rs4646994) has been associated with ACE activity. The ACE DD genotype is associated with increased circulating ACE levels, which are generally two times as high as those found for II genotypes. Although most reports suggest that the I allele predisposes to human endurance (1) the literature also contains some opposite data (2). These inconsistencies from genetic association studies relating to the ACE gene and its I/D polymorphism maybe attributable, partially, to epigenetic factors that have been reported to influence ACE activity. Indeed, if both copies of the ACE D/D gene are transiently methylated, ACE increased levels associated with this polymorphism, may be down-regulated. However, there have not been any reports that address whether epigenetic regulation of the ACE gene is specifically involved in modifying human endurance, but, importantly, the human ACE gene promoter has been shown to harbor CpG islands. It is well established that environmental factors may modify the epigenetic profile and that nutrition training, muscle unloading and mechanical stimulation significantly impact on performance, playing an epigenetic role . Hence, it is conceivable that some of these factors might influence the CpG islands within the ACE promoter affecting its expression. The present study is aimed at modulating the epigenetic pattern of the ACE promoter by administering arginine to professional soccer players. ACE (DD, ID, and II) will be genotyped by PCR, then the epigenetic profile of ACE (gene promoter methylation) will be determined by bisulfite method, the serum levels of angiotensin 2 will be measured by ELISA. Hence, we compare the performance capacity of soccer players exhibiting different ACE polymorphisms, by strength, speed, and endurance tests. Subsequently, we will split the subjects under study in 2 groups: group 1 will follow a mediterrean diet, group 2 will follow the same mediterrean diet supplemented with arginine. After six months we will analyze if an epigenetic regulation of the ACE gene has occurred, modulating endurance performance.

Nandrolone increases angiotensin-I converting enzyme activity in rats tendons

INTRODUCTION: The renin-angiotensin system (RAS) has been associated with several biological processes of the human body, regulating, among others blood pressure and water and electrolytes balance. Moreover, RAS also regulates connective tissue growth. Recently, studies have shown that the use of nandrolone modifies the angiotensin-I converting enzyme (ACE) activity and increases collagen deposition in the heart. OBJECTIVE: The aim of study was to evaluate the Angiotensin-I converting enzyme (ACE) activity in the superficial flexor tendon (SFT) and in serum after load exercise in combination with anabolic androgenic steroid (AAS) administration after training session and six weeks of detraining. METHODS: Forty-eight Wistar rats were used into two groups (G1 and G2) subdivided into four subgroups: Sedentary (S); trained (T); AAS-treated (Deca-Durabolin(r), 5mg/kg, twice a week) sedentary rats (AAS) and AAS-treated and trained animals (AAST). Trained groups performed jumps in water: four series of 10 jumps each, followed by a 30 sec interval between the series, for seven weeks. RESULTS: Training increased ACE activity in the SFT compared to the control group (p &lt;0.05). Both AAS and AAST groups presented higher ACE activity levels (p &lt; 0.05). The AAST increased the ACE activity only compared to the trained animals. Only the AAST group presented significant higher levels of ACE in the serum. In the G2 group, all experimental groups presented decreased ACE activity in the serum and in the tendon, as compared to the control group. CONCLUSION: This study indicates that AAS administration and its combination with exercise increased ACE activity of tendons. AAS abuse could compromise tendon adaptation causing maladaptive remodeling.

Astaxanthin modulates osteopontin and transforming growth factor β1 expression levels in a rat model of nephrolithiasis: a comparison with citrate administration

To evaluate the effect of astaxanthin on renal angiotensin-I converting enzyme (ACE) levels, osteopontin (OPN) and transforming growth factor β1 (TGF-β1) expressions and the extent of crystal deposition in experimentally induced calcium oxalate kidney stone disease in a male Wistar rat model. To compare the efficacy of astaxanthin treatment with a currently used treatment strategy (citrate administration) for kidney stones. The expression of OPN was assessed by immunohistochemistry. One step reverse transcriptase polymerase chain reaction followed by densitometry was used to assess renal OPN and TGF-β1 levels. Renal ACE levels were quantified by an enzyme-linked immunosorbent assay method. Crystal deposition in kidney was analysed by scanning electron microscopic (SEM)-energy-dispersive X-ray (EDX). The renal ACE levels and the expression of OPN and TGF-β1 were upregulated in the nephrolithiasis-induced rats. Astaxanthin treatment reduced renal ACE levels and the expression OPN and TGF-β1. SEM-EDX analysis showed that crystal deposition was reduced in the astaxanthin-treated nephrolithiatic group. Astaxanthin treatment was more effective than citrate administration in the regulation of renal ACE levels, OPN and TGF-β1 expressions. Astaxanthin administration reduced renal calcium oxalate crystal deposition possibly by modulating the renal renin-angiotensin system (RAS), which reduced the expression of OPN and TGF-β1 levels. Astaxanthin administration was more effective than citrate treatment in reducing crystal deposition and down-regulating the expression of OPN and TGF-β1.

A Novel Splice-Site Mutation in Angiotensin I-Converting Enzyme (ACE) Gene, c.3691+1G&gt;A (IVS25+1G&gt;A), Causes a Dramatic Increase in Circulating ACE through Deletion of the Transmembrane Anchor

BackgroundAngiotensin-converting enzyme (ACE) (EC 4.15.1) metabolizes many biologically active peptides and plays a key role in blood pressure regulation and vascular remodeling. Elevated ACE levels are associated with different cardiovascular and respiratory diseases.Methods and ResultsTwo Belgian families with a 8-16-fold increase in blood ACE level were incidentally identified. A novel heterozygous splice site mutation of intron 25 - IVS25+1G>A (c.3691+1G>A) - cosegregating with elevated plasma ACE was identified in both pedigrees. Messenger RNA analysis revealed that the mutation led to the retention of intron 25 and Premature Termination Codon generation. Subjects harboring the mutation were mostly normotensive, had no left ventricular hypertrophy or cardiovascular disease. The levels of renin-angiotensin-aldosterone system components in the mutated cases and wild-type controls were similar, both at baseline and after 50 mg captopril. Compared with non-affected members, quantification of ACE surface expression and shedding using flow cytometry assay of dendritic cells derived from peripheral blood monocytes of affected members, demonstrated a 50% decrease and 3-fold increase, respectively. Together with a dramatic increase in circulating ACE levels, these findings argue in favor of deletion of transmembrane anchor, leading to direct secretion of ACE out of cells.ConclusionsWe describe a novel mutation of the ACE gene associated with a major familial elevation of circulating ACE, without evidence of activation of the renin-angiotensin system, target organ damage or cardiovascular complications. These data are consistent with the hypothesis that membrane-bound ACE, rather than circulating ACE, is responsible for Angiotensin II generation and its cardiovascular consequences.

Angiotensin converting enzyme (ACE D/I) polymorphism and its relation to liver fibrosis progression in Egyptian patients with chronic hepatitis C virus infection

Hepatitis C virus (HCV) infection is a global health problem in Egypt and causes different liver disease spectrum. Evidence indicates that angiotensin I converting enzyme (ACE) gene polymorphism may play a role in determining disease progression. We aimed to determine the association of ACE gene I/D polymorphism with ACE serum levels and to examine the association between different I/D genotypes with the severity of hepatic fibrosis in chronic HCV infected Egyptian patients. Thirty controls and 90 HCV infected patients participated in the study, patients were subgrouped by Ishak stage of fibrosis into subgroup IIa (n=30; fibrosis score 0–1), subgroup IIb (n=38; fibrosis score 2–3) and subgroup IIc (n=22; fibrosis score 4–6). DNA was multiplied by polymerase chain reaction (PCR). ACE genotype frequency in HCV infected patients was significantly different comparing to controls (X2=7.169, P=0.028). With non-significant difference in ACE D/I genotypes and allele frequencies among the patient subgroups (P>0.05),the frequency of the DD, DI and II genotypes in subgroup IIa, subgroup IIb and subgroup IIc were (53.3%, 36.6%, 10%), (44.7%, 44.7%, 10.5%) and (50%, 22.7%, 27%), respectively. The D and I allele frequency were (71.66%, 28.33%), (67.1%, 32.9%) and (61.36%, 38.63%), respectively. ACE serum levels were significantly increased in DD more than DI and II (t=2.56, 3.43, P<0.05), respectively, with non-significant association in sonographic findings, viral load and liver function test (LFT) parameters with the ACE genotypes. Serum ACE levels were significantly increased in all patient subgroups when compared to controls with a non significant difference of ACE levels between subgroup IIb and IIc. We concluded that the D/D genotype is associated with HCV infection but not associated with degree or the progression of hepatic fibrosis.

Serum angiotensin I-converting enzyme response to exercise; no differential effect of genotype

Angiotensin I-converting enzyme (ACE) plays a pivotal role in whole body fluid balance and the degradation of bradykinin. A common allelic variant with a 287 base pair insert has been...

No association betweenACEolymorphism and risk of nasopharyngeal carcinoma

Emerging evidence has shown that angiotensin I-converting enzyme (ACE) plays pivotal roles not only in the regulation of cardiovascular homeostasis but also in the process of tumorigenesis. A common ACE I/D polymorphism has been found to be functional, with the D allele displaying a higher plasma ACE level and ACE activity. The purpose of this study was to investigate whether the ACE I/D polymorphism was related to the risk of nasopharyngeal carcinoma (NPC). The study included 175 patients with NPC and 279 age- and sex-matched control subjects. The ACE I/D polymorphism was identified by a polymerase chain reaction analysis. No association was found between the ACE I/D polymorphism and risk of NPC (ID vs. II: odds ratio [OR] = 0.77, 95% confidence interval [CI] 0.51-1.17; DD vs. II: OR = 0.98, 95%CI 0.56-1.72, respectively). This finding indicates that the ACE I/D polymorphism may not play a role in susceptibility to NPC. Further studies are warranted to confirm this finding, especially in ethnically disparate populations.

Cocaine administration increases angiotensin I-converting enzyme (ACE) expression and activity in the rat striatum and frontal cortex

Some central effects of cocaine administration seem to be related to angiotensin II (Ang II) or its metabolites. Nonetheless, it is still an open question whether or not the levels of angiotensin I-converting enzyme (ACE), the main Ang II generating enzyme, are modified by cocaine administration. To evaluate the effect of acute and subchronic cocaine administration on ACE activity and mRNA expression, male rats were randomly assigned to saline or cocaine group. Acute and subchronic cocaine administration induced a significant increase in ACE activity and mRNA expression in the frontal cortex and striatum but not in the hippocampus. These results suggest that some of the Ang II related effects of cocaine upon the central nervous system can be mediated by changes on the expression and activity of ACE in the striatum and frontal cortex.

An Angiotensin I-Converting Enzyme Mutation (Y465D) Causes a Dramatic Increase in Blood ACE via Accelerated ACE Shedding

BackgroundAngiotensin I-converting enzyme (ACE) metabolizes a range of peptidic substrates and plays a key role in blood pressure regulation and vascular remodeling. Thus, elevated ACE levels may be associated with an increased risk for different cardiovascular or respiratory diseases. Previously, a striking familial elevation in blood ACE was explained by mutations in the ACE juxtamembrane region that enhanced the cleavage-secretion process. Recently, we found a family whose affected members had a 6-fold increase in blood ACE and a Tyr465Asp (Y465D) substitution, distal to the stalk region, in the N domain of ACE.Methodology/Principal FindingsHEK and CHO cells expressing mutant (Tyr465Asp) ACE demonstrate a 3- and 8-fold increase, respectively, in the rate of ACE shedding compared to wild-type ACE. Conformational fingerprinting of mutant ACE demonstrated dramatic changes in ACE conformation in several different epitopes of ACE. Cell ELISA carried out on CHO-ACE cells also demonstrated significant changes in local ACE conformation, particularly proximal to the stalk region. However, the cleavage site of the mutant ACE - between Arg1203 and Ser1204 - was the same as that of WT ACE. The Y465D substitution is localized in the interface of the N-domain dimer (from the crystal structure) and abolishes a hydrogen bond between Tyr465 in one monomer and Asp462 in another.Conclusions/SignificanceThe Y465D substitution results in dramatic increase in the rate of ACE shedding and is associated with significant local conformational changes in ACE. These changes could result in increased ACE dimerization and accessibility of the stalk region or the entire sACE, thus increasing the rate of cleavage by the putative ACE secretase (sheddase).

Effects of acute exercise on angiotensin I‐converting enzyme (ACE) activity in horses

Angiotensin I-converting enzyme (ACE) level measurement in blood samples is an important tool in human medicine for the detection, treatment and control of diseases such as sarcoidosis and hypertension. Recently ACE has been advocated as being correlated to athletic aptitude in human athletes and a genetic polymorphism has been shown to be responsible for the enzymatic levels in the circulation. The objective of this research was to evaluate the effects of acute exercise in horses in order to increase the understanding of a possible correlation between ACE levels in plasma and performance in equine athletes. A standardised exercise test (SET) to fatigue was conducted on 8 horses and repeated venous blood collections carried out for ACE activity measurements before, during and after the SET. Our results show an increase in ACE activity up to fatigue and a return to baseline values at 30 min post exercise.

No association between angiotensin I converting enzyme (ACE) I/D polymorphism and gastric cancer risk among Japanese.

The angiotensin I-converting enzyme (ACE) is involved in cell proliferation, angiogenesis, inflammation, and tissue remodeling, all of which could play a role in carcinogenesis. The DD genotype of ACE I/D polymorphism with a higher ACE level than either ID or II genotypes was reported to increase the risk of several cancers. This is a case-control study examining the association between the polymorphism and gastric cancer risks among Japanese. Cases numbered 583 patients aged 27 to 80 years with gastric cancer diagnosed at the Aichi Cancer Center Hospital from 2001 to 2005. Controls were 1,742 sex and age frequency-matched cancer-free patients, who visited the same hospital during that same period. The ACE I/D polymorphism was genotyped using a polymerase chain reaction with confronting two-pair primers. The results showed that the age- and sex- adjusted ORs of gastric cancer were 0.95 (95% CI, 0.78-1.16) for ID, and 1.08 (95% CI, 0.80-1.46) for DD relative to II. Among the controls with H. pylori sero-positive or gastric atrophy (GA), the ORs of ID and DD relative to II were 1.20 (95% CI, 0.88-1.63) and 1.16 (95% CI, 0.73-1.84) for mild GA, and 1.22 (95% CI, 0.84-1.78) and 1.08 (95% CI, 0.61-1.89) for severe GA, respectively. In conclusion, there was no significant association of the ACE I/D polymorphism with the risk of gastric cancer. Among the controls, the polymorphism was not associated with the severity of GA.