Extracellular vesicles and angiotensin-converting enzyme 2 in COVID-19 disease

Extracellular vesicles(EVs)are membranous vesicular structures released from almost all eukaryotic cell types under different physiological or pathological conditions.Growing evidence demonstrates that EVs can serve as mediators of intercellular communication between donor and recipient cells or microorganism-infected and noninfected cells.Coronavirus disease 2019(COVID-19)disease is caused by infection of the severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)of host cells in the respiratory system and various extra-pulmonary tissue/organs,resulting in complications of multiple organ systems.As the cell surface receptor,angiotensin-converting enzyme 2(ACE2)mediates cellular entry of SARS-CoV-2 into the host cells in patients with COVID-19.Recent studies have found that ACE2 can be released with EVs,which have been shown to interfere with the entry of the virus into host cells and thus may be involved in COVID-19 pathophysiology.In addition,ACE2,neprilysin(NEP),and thimet oligopeptidase(TOP)are the key enzymes that regulate angiotensin metabolism by converting angiotensin II or angiotensin I to angiotensin 1-7,the latter of which has protective effects in counterbalancing the harmful effects of angiotensin II in COVID-19 disease.This review summarizes the recent research progress regarding EV-associated ACE2,NEP,and TOP and the perspectives of their potential involvement in the pathophysiology of COVID-19 disease.

Origin and genomic characteristics of SARS-CoV-2 and its interaction with angiotensin converting enzyme type 2 receptors, focusing on the gastrointestinal tract

The emergence of coronavirus disease-2019 induced by a newly identified bcoronavirus, namely severe acute respiratory syndrome coronavirus 2(SARSCoV-2) has constituted a public health emergency. Even though it was considered a zoonotic disease, the virus has also spread among humans via respiratory secretions. The expression and distribution of angiotensin converting enzyme type 2(ACE2) in various human organs might also show other possible infection routes. High ACE2 ribonucleic acid expression has been identified in the gastrointestinal tract(GI) indicating its importance as a possible infection pathway of SARS-CoV-2. ACE2 induces viral entry into the host and most importantly has been found to be associated with the function of the gut. Its deficiency has been implicated in several pathologies such as colorectal inflammation. The renin-angiotensin system(RAS) is an essential regulatory cascade operating both at a local tissue level and at the systemic or circulatory level. The RAS may be important in the pathogenesis of chronic liver disease and is associated with the up-regulation of ACE2. Thus, the aim of this review is firstly, the analysis of some important general and genome characteristics of SARS-CoV-2 and secondly, and most importantly, to focus on the utility of ACE2 receptors in both SARS-CoV-2 replication and pathogenesis, especially in the GI tract.

Angiotensin converting enzymes inhibitors or angiotensin receptor blockers should be continued in COVID-19 patients with hypertension

BACKGROUND Recent studies have revealed that sustained ingestion of angiotensin converting enzymes inhibitors or angiotensin receptor blockers(ACEIs/ARBs)had no harmful effects on coronavirus disease 2019(COVID-19)patients complicated with hypertension.AIM To investigate the impact on COVID-19 patients complicated with hypertension who discontinued using ACEIs/ARBs.METHODS All COVID-19 patients complicated with hypertension admitted to our isolated unit were consecutively recruited in this study.Some patients switched from ACEIs/ARBs to calcium channel blocker(CCBs)after admission,while others continued using non-ACEIs/ARBs.We compared characteristics and clinical outcomes between these two groups of patients.RESULTS A total of 53 patients were enrolled,27 patients switched from ACEIs/ARBs to CCBs while 26 patients continued with non-ACEIs/ARBs.After controlling potential confounding factors using the Cox proportional hazards model,hospital stay was longer in patients who discontinued ACEIs/ARBs,with a hazard ratio of 0.424(95%confidence interval:0.187-0.962;P=0.040),upon discharge than patients using other anti-hypertensive drugs.A sub-group analysis showed that the effect of discontinuing use of ACEIs/ARBs was stronger in moderate cases[hazard ratio=0.224(95%confidence interval:0.005-0.998;P=0.0497)].CONCLUSION Patients in the discontinued ACEIs/ARBs group had longer hospital stays.Our findings suggest that COVID-19 patients complicated with hypertension should continue to use ACEIs/ARBs.

Effects of Yinchenhao Decoction on Self-regulation of Renin-angiotensin System by Targeting Angiotensin Converting Enzyme 2 in Bile Duct-ligated Rat Liver

Summary： In order to investigate whether Yinchenhao decoction （YCHD） attenuates hepatic fibro- genesis in the bile duct ligation （BDL） model via recovering and restoring the self-regulation and bal- ance of the renin-angiotensin system （RAS）, 33 specific-pathogen-free （SPF） male Sprague-Dawley rats with common BDL and scission were randomly divided into five groups as follows： G1, the sham group （n=4）; G2, BDL 7-day group （n=5）; G3, BDL＋YCHD 430 mg/mL （n=8）; G4, BDL＋losartan 0.65 mg/mL （ARB group, n=8）; G5, model group （BDL without any treatment, n=8）. YCHD and losartan （10 mL.kgl.day-1） were given by gastric gavage for 16 days following BDL in G3 and G4 groups, respec- tively. The effect of YCHD on liver fibrosis and the detailed molecular mechanisms were assessed by liver function including total bilirubin （TBIL）, direct bilirubin （DBIL）, indirect bilirubin （IDBIL）, alanine aminotransferase （ALT）, and aspartate aminotransferase （AST）. Histological changes were ob-. served by transmission electron microscopy （TEM） and Masson trichrome staining. Western blotting was used to detect the protein expression level of the renin-angiotensin system （RAS） components in- cluding angiotensin converting enzyme （ACE）, angiotensin II type 1 receptor （AT1R）, ACE2, angio- tensin II （Ang II） as well as transforming growth factor 131 （TGF131）. The experimental data were ana- lyzed by principle component analytical method of pattern recognition. The results showed that bio- chemically, serum TBIL, DBIL, IDBIL, ALT and AST levels were markedly increased following BDL as compared with the sham group （P〈0.05）. Serum TBIL, IDBIL and DBIL levels in G3 group were dramatically decreased as compared with G5 and G4 groups （P〈0.05）. Serum AST level in G3 was sig- nificantly lowered than in G5 group （P〈0.05）, but there was no significant difference in ALT among G3, G4 and G5 groups （P〉0.05）. Histologically, livers in G3 group showed less hepatocytes necrosis, less bile duct hyperplasia and less collagen formation than in G4 and G5 groups. The protein expression lev- els of ACE2, ACE, Ang II, AT1R and TGF131 in G2, G3 and G4 groups were significantly higher than in sham group （P〈0.05）, and lower than in G5 group （P〈0.05）. However, the differences among G2, G3 and G4 groups were not significant （P〉0.05）. ACE2 protein expression in G3 group was significantly higher than in G2 group （P〈0.05） and there was no significant difference in comparison with G4 group （P〉0.05）. Moreover, the protein expression of TGF131 in G3 group was significantly lower than in G5 and G4 groups （P〈0.05）. Our findings suggest that the antifibrotic effects of YCHD may be associated with the decreased classical RAS pathway components and TGFI31 downexpression so as to recover and rebuild self-regulation of the RAS by elevating the protein expression of ACE2.

A Novel Angiotensin I Converting Enzyme Inhibitory Peptide from the Milk Casein:Virtual Screening and Docking Studies

Angiotensin I converting enzyme （ACE） plays an important physiological role in the regulation of hypertension. In this study, we applied virtual screening to discover a novel angiotensin I converting enzyme inhibitory peptides from milk casein. One potential hit was identified based on docking scores, subsequently confirmed by activity studies in vitro （IC50=20.85 μmol L-1）. The proposed peptide in this study contains a unique sequence, Lys-Val-Leu-Ile-Leu-Ala. Moreover, we performed the docking studies to understand the binding mode between the enzyme and peptide hit.

Effect of angiotensin Ⅱ type 1 receptor blocker and angiotensin converting enzyme inhibitor on the intraocular growth factors and their receptors in streptozotocin-induced diabetic rats

AIM： To investigate the effect of angiotensin II type 1 receptor blocker （ARB） and angiotensin converting enzyme inhibitor （ACEI） on intraocular growth factors and their receptors in streptozotocin-induced diabetic rats. METHODS： Forty Sprague-Dawley rats were divided into 4 groups： control, diabetes mellitus （DM）, candesartan- treated DM, and enalapril-treated DM （each group, n---10）. After the induction of DM by streptozotocin, candesartan [ARB, 5 mg/（kg · d）] and enalapril [ACEI, 10 mg/（kg · d）] were administered to rats orally for 4Wko Vascular endothelial growth factor （VEGF） and angiotensin II （Ang II） concentrations in the vitreous were measured using enzyme-linked immunosorbent assays, and VEGF receptor 2 and angiotensin II type 1 receptor （ATIR） levels were assessed at week 4 by Western blotting. RESULTS： Vitreous Ang II levels were significantly higher in the DM group and candesartan-treated DM group than in the control （P=0.04 and 0.005, respectively）. Vitreous ATIR increased significantly in DM compared to the other three groups （P〈0.007）. Candesartan-treated DM rats showed higher vitreal ATIR concentration than the enalapril-treated DM group and control （P〈0.001 and P=0.005, respectively）. No difference in vitreous Ang II and ATIR concentration was found between the enalapril- treated DM group and control. VEGF and its receptor were below the minimum detection limit in all 4 groups. CONCLUSION： Increased Ang II and ATIR in the hyperglycemic state indicate activated the intraocular renin-angiotensin system, which is inhibited more effectively by systemic ACEI than systemic ARB.

Role of angiotensin converting enzyme and angiotensinogen gene polymorphisms in angiotensin converting enzyme inhibitor-mediated antiproteinuric action in type 2 diabetic nephropathy patients

AIM To investigate the role of genetic variants of angiotensin converting enzyme(ACE) and angiotensinogen(AGT) genes in the antiproteinuric efficacy of ACE inhibitor therapy in diabetic nephropathy(DN) patients.METHODS In the present study, 270 type 2 diabetes mellitus patients with nephropathy were enrolled and treated with ACE inhibitor(ramipril) and followed at 6 mo for renal function and albumin excretion by estimating serum creatinine, end stage renal disease, and albumin/creatinine ratio(ACR) in urine. Genotyping of ACE I/D and AGT M235 T polymorphisms were performed by using primer specific polymerase chain reaction(PCR) and PCR-RFLP techniques, respectively. RESULTS Forty-eight percent of DN patients(responders) benefited with respect to proteinuria from ACE inhibitor therapy at 6 mo follow-up. A significant reduction in ACR was observed after 6 mo treatment with ACE inhibitor irrespective of whether DN patients were micro-albuminuric(≥ 30 and < 300 mg/g creatinine) or macro-albuminuric(≥ 300 mg/g creatinine) at the time of enrollment. However, macro-albuminuric patients(55%) showed better response to therapy. A reduction in urinary ACR was found independent of genotypes of ACE I/D and AGT M235 T polymorphisms although macro-albuminuric patients having TT genotype showed statistically insignificant increased response(72%). CONCLUSION ACE inhibitor therapy reduced urinary ACR by ≥ 30% in 50% of DN patients and the response is independent of ACE I/D and AGT M235 T polymorphisms.

Expression of tumor necrosis factor-alpha converting enzyme in liver regeneration after partial hepatectomy

AIM:To study the expression of tumor necrosis factor- alpha converting enzyme (TACE) and evaluate its significance in liver regeneration after partial hepatectomy in vivo. METHODS: Male SD rats underwent 70% partial hepatec- tomy. The remaining liver and spleen tissue samples were collected at indicated time points after hepatectomy. TACE expression was investigated by Western blotting, immunohistochemistry, and serial section immunostaining. RESULTS: Expression of TACE in liver and spleen tissues after partial hepatectomy was a time-dependent alteration, reaching a maximal level between 24 and 48 h and remaining elevated for more than 168 h. TACE protein was localized to mononuclear cells (MNC), which infiltrated the liver from the spleen after hepatectomy. The kinetics of TACE expression was in accordance with the number of TACE-staining MNCs and synchronized with those of transforming growth factor-α (TGFα). In addition, TACE-staining MNC partially overlapped with CD3+ T lymphocytes. CONCLUSION: TACE may be involved in liver regenera- tion by pathway mediated with TGFα-EGFR in the cell- cycle progressive phase in vivo. TACE production and effect by paracrine may be a pathway of involvement in liver regeneration for the activated CD3+ T lymphocytes.

Long-term Administration of Angiotension-Converting Enzyme Inhibitor Improves the Outcome of Chronic Heart Failure in Senile Patients

One hundred and sixteen senile patients (older than 65 years) with chronic heart failure (CHF) were analyzed retrospectively in order to verify if old patients with CHF would benefit from long term (one year) angiotension converting enzym e inhibitor (ACEI) treatment. The frequency of drugs (including ACEI, digitalis and diuretic) used was stratified into four degrees accordingly. Develop ment of the CHF was scored with regard to relapse rate and severity of this dise ase. Stepwise regression analysis was applied to explore the relationship betwee n the scored outcome of CHF and the frequency of individual drug administration. A significant relationship of the scored outcome of CHF to the frequency of ACE I usage but not to digitalis nor to diuretics was found (partial coefficient of the correlation r =0.42, P =0.002). It was concluded that the long term a dministration of ACEI improves the outcome of CHF in senile patients.

Liquid Chromatographic Assay of Peptides Activity with Inhibiting Angiotensin Converting Enzyme

A rapid, simple and interference-free method was developed to evaluate the inhibitory activity of hydrolyzed peptides from egg white protein against the angiotensin-converting enzyme. The total reaction volume was 60 μL, saving the cost. The assay was based on a HPLC separation and quantification of the synthetic substrate hippuryl-L-histidyl-L-leucine and its hydrolyzed product-hippuric acid; the separation was performed on a C18 column eluted by a mobile phase of acetonitrile/water（0.5% TFA） at a volume ratio of 25：75. At a signal to noise ratio（S/N） of 10, the detective limit of the quantitation of hippuric acid was （0.4600±0.0097） μmol/L. The standard curve shows a linear response with a slope of 49488 and a correlation coefficient of 0.9995. The assay was adequate for the study of ACE inhibition by Captopril and peptides derived from food protein, and showed a very good correlation with the previous methods.

Comparison of Properties of Tumor Necrosis Factor-α Converting Enzyme (TACE) and Some Matrix Metalloproteases (MMPs) in Catalytic Domains

The crystal structural data of TACE, MMP-1, MMP-2, MMP-3 and MMP-9 were obtained from PDB database, and then their catalytic domains＇ properties including conformation, molecular surface hydrophobicity and electrostatic potential were analyzed and compared by using Insight II molecular modeling software. It was found that the conformation and molecular surface hydrophobicity of catalytic domains of TACE and MMPs were not obviously different, but the molecular surface electrostatic potential of catalytic domain of TACE＇ and MMPs had obvious differences. The findings are helpful in the Rational Drug Design of TACE selective inhibitor.

Expression of Extracellular Signal-regulated Kinase and Angiotensin-converting Enzyme in Human Atria during Atrial Fibrillation

In order to investigate the changes in the expression of extracellular signal regulated kinase (ERK1/ERK2) and angiotensin converting enzyme (ACE) in the patients with atrial fibrillation (AF), 52 patients with rheumatic heart diseases were examined. Nineteen patients had chronic persistent AF (AF≥6 months, CAF), 12 patients had paroxymal AF (PAF) and 21 patients had no history of AF. The ERK expression was detected at the mRNA level by reverse transcription polymerase chain reaction, at the protein level by Western blotting and at atrial tissue level by immunohistochemistry. ERK activating kinases (MEK1/2) and ACE were determined by Western blotting techniques. The expression of ERK2 mRNA was increased in the patients with CAF (74±19 U vs sinus rhythm: 32±24 U, P <0.05). Activated ERK1/ERK2 and MEK1/2 were increased to more than 150 % in the patients with AF compared to those with sinus rhythm. No significant difference between CAF and PAF was found. The expression of ACE was three fold increased in the patients with CAF compared to those with sinus rhythm. Patients with AF showed an increased expression of ERK1/ERK2 in atrial interstitial cells and marked atrial fibrosis. An ACE dependent increase in the amounts of activated ERK1/ERK2 in atrial interstitial cells may be one of molecular mechanisms for the development of atrial fibrosis in the patients with AF. These findings may have important impact on the treatment of AF.

Drying Technology of Angiotensin Converting Enzyme Inhibitory Peptide Derived from Bovine Casein

Drying technology of angiotensin converting enzyme （ACE） inhibitory peptides derived from bovine casein was investigated. No significance was observed on ACE inhibitory activity of products prepared by spay drying and freeze drying （P〉0.05）. Spay drying was the best drying process for practical industry production. The inlet temperature ranged from 140℃ to 160℃ and the exit temperature ranged from 70 ℃ to 90 ℃ during the spay drying process. Under the optimal conditions, scale-up of angiotensin converted enzyme inhibitory peptide from 1 L to 10 L and the experiment was successively conducted. Peptide yield was 29% and half inhibitory concentration （IC50） was 0.53 g. L^-1.

Angiotensin-converting enzyme 2 receptors,chronic liver diseases,common medications,and clinical outcomes in coronavirus disease 2019 patients

The severe acute respiratory syndrome coronavirus 2(SARS-CoV-2),the virus responsible for coronavirus disease 2019(COVID-19),enters affected cells through the angiotensin-converting enzyme 2(ACE2)receptor,which is highly expressed in type II alveolar cells,enterocytes,and cholangiocytes.SARS-CoV-2 infection causes fever,dry cough,and breathing difficulty,which can progress to respiratory distress due to interstitial pneumonia,and hepatobiliary injury due to COVID-19 is increasingly recognized.The hepatobiliary injury may be evident at presentation of the disease or develop during the disease progression.The development of more severe clinical outcomes in patients with chronic liver diseases(CLD)with or without cirrhosis infected with SARS-CoV-2 has not been elucidated.Moreover,there is limited data related to common medications that affect the disease severity of COVID-19 patients.Additionally,ACE2 receptor expression of hepatobiliary tissue related to the disease severity also have not been clarified.This review summarized the current situation regarding the clinical outcomes of COVID-19 patients with chronic liver diseases who were treated with common medications.Furthermore,the association between ACE2 receptor expression and disease severity in these patients is discussed.

Mobola plum seed methanolic extracts exhibit mixed type inhibition of angiotensinⅠ-converting enzyme in vitro

Objective: To explore the possible inhibitory potentials and mechanism by Mobola plum(Parinari curatellifolia) seeds crude methanol(CE) and flavonoid-rich(FE) extracts on angiotensin-1-converting enzyme(ACE Ⅰ).Methods: The sensitivity and kinetic model of inhibition of CE and FE on ACE Ⅰ using N-[3-(2-furyl)-acryloyl]-Phe-Gly-Gly as enzyme substrate for ACE Ⅰ was evaluated by Michealis Menten approach. The inhibition mechanism was explored from Lineweaver–Burk model and IC_(50) was determined from Cheng–Prusoff empirical analysis.Results: The IC_(50) of CE and FE were 13.54 and 39.38 mg/m L, respectively. Both extracts exhibited mixed type inhibition with the inhibitory constant(K_i) of CE was between0.38 and 0.37 mg/m L while that of FE showed a two-fold increase(1.62 mg/mL and0.28 mg/mL). FE on ACE Ⅰ demonstrated positive cooperativity with a Hill's coefficient of1.89.Conclusions: The study reveals the superior ACE Ⅰ inhibitory potential of CE over FE and suggest that mixed inhibition pattern of the enzyme might be the underlying mechanism of antihypertensive activity.

Left ventricular hypertrophy in relation to systolic blood pressure and the angiotensin converting enzyme I/D polymorphism in Chinese

Objective There is little population-based data on the prevalence and the environmental or genetic determinants of left ventricular hypertrophy （LVH） in China. The purpose of this paper is to study LVH in relation to systolic blood pressure and the angiotensin converting enzyme （ACE） insertion/deletion（I/D） polymorphism in Chinese. Methods We recorded 12- lead ECG （CardioSoft, v4.2） in 1365 residents in the Jingning County, Zhejiang Province, China. LVH was defined according to the gender-specific Sokolow-Lyon and Cornell product ECG criteria. Results Regardless of whether the Sokolow-Lyon or Cornell product ECG criteria was used, the prevalence of LVH （20.7% and 4.8%, respectively） significantly （P〈0.0001） increased with male gender （odds ratio [OR] 2.33 and 7.15） and systolic blood pressure （per 10 mm Hg increase, OR 1.46 and 1.33）. If the Sokolow-Lyon criteria was used, the prevalence of LVH was also influenced by alcohol intake （OR 1.44, P=-0.03） and body mass index （OR 0.83, P=0.0005）. The association between the Sokolow-Lyon voltage amplitude and the ACE I/D polymorphism was dependent on antihypertensive therapy （P=0.01）. In 1262 untreated subjects, but not 103 patients on antihypertensive medication, the ACE DD compared with II subjects had significantly higher Sokolow-Lyon voltage amplitudes （29.8：-0.6 vs. 28.0-3：0.5 mV, P=-0.02） and higher risk of LVH （OR 1.74, 95% CI： 1.12-2.69, P=-0.01）. Conclusion LVH is prevalent in Chinese, and is associated with systolic blood pressure and the ACE D allele. The genetic association might be modulated by antihypertensive therapy（J Geriatr Cardio12009; 6：131-136）.

Circulating angiotensin converting enzyme 2 and COVID-19

The severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)has triggered a widespread outbreak since December 2019.The SARS-CoV-2 infection-related illness has been dubbed the coronavirus disease 2019(COVID-19)by the World Health Organization.Asymptomatic and subclinical infections,a severe hyperinflammatory state,and mortality are all examples of clinical signs.After attaching to the angiotensin converting enzyme 2(ACE2)receptor,the SARSCoV-2 virus can enter cells through membrane fusion and endocytosis.In addition to enabling viruses to cling to target cells,the connection between the spike protein(S-protein)of SARS-CoV-2 and ACE2 may potentially impair the functionality of ACE2.Blood pressure is controlled by ACE2,which catalyzes the hydrolysis of the active vasoconstrictor octapeptide angiotensin(Ang)II to the heptapeptide Ang-(1-7)and free L-Phe.Additionally,Ang I can be broken down by ACE2 into Ang-(1-9)and metabolized into Ang-(1-7).Numerous studies have demonstrated that circulating ACE2(cACE2)and Ang-(1-7)have the ability to restore myocardial damage in a variety of cardiovascular diseases and have antiinflammatory,antioxidant,anti-apoptotic,and anti-cardiomyocyte fibrosis actions.There have been some suggestions for raising ACE2 expression in COVID-19 patients,which might be used as a target for the creation of novel treatment therapies.With regard to this,SARS-CoV-2 is neutralized by soluble recombinant human ACE2(hrsACE2),which binds the viral S-protein and reduces damage to a variety of organs,including the heart,kidneys,and lungs,by lowering Ang II concentrations and enhancing conversion to Ang-(1-7).This review aims to investigate how the presence of SARS-CoV-2 and cACE2 are related.Additionally,there will be discussion of a number of potential therapeutic approaches to tip the ACE/ACE-2 balance in favor of the ACE-2/Ang-(1-7)axis.

POLYMORPHISM OF ANGIOTENSIN CONVERTING ENZYME GENE AND GENETIC SUSCEPTIBILITY TO ASTHMA WITH FAMILIAL AGGREGATION

Angiotensin converting enzyme (ACE) plays a key role in the metabolism of angiotensin Ⅱ (AT Ⅱ) and inactivation of bradykinins and tachykinins, which are potent bronchialconstrictors and mediators of inflammation asthma, and ACE is heavily expressed in the lungs. An insertion deletion (D/I) polymorphism of ACE gene has been shown to be associated with levels of ACE. We investigate whether the polymorphism of ACE gene is associated with asthma and bronchial responsiveness. Methods. A case control study was carried out in 50 asthmatics, 7 families with at least 2 asthmatic individuals, and 50 healthy subjects. The insertion/deletion (I/D) polymorphism of ACE gene was amplified by polymerase chain reaction (PCR). Methacholine brocho provocation and pulmonary function tests were performed in all asthmatics. Results. There was an higher gene frequency of DD genotype of ACE gene in asthmatic subjects and families individuals compared with healthy subjects (46%, 53% vs 16%, P<0 05; odd ratio 4 98). Anhigher prevalence of DD genotype of ACE was in patients with bronchial hyperresposiveness (BHR) (67%vs 33%, P<0 05; odd ratio 3 8). Accordingly, the mean values of FEV 1% and FEV 1/FVC were higher in asthmatics carrying non DD alleles than patients with DD genotype (73 78% vs 56 56%, P<0 05; 79 19% vs 69 29%, P<0 05, respectively). Conclusion. These results suggested that DD allele of ACE genotype was significantly involved in genetic susceptibility to asthma. DD genotype of ACE might be a risk factor for the degree of airway obstruction, it could also be implicated in pathogenesis of bronchial hyperresponsiveness.

Purification and Characterization of Angiotensin I Converting Enzyme Inhibition Peptides from Sandworm Sipunculus nudus

Three angiotensin I converting enzyme(ACE) inhibition peptides were isolated from sandworm Sipunculus nudus protein hydrolysate prepared using protamex. Consecutive purification methods, including size exclusion chromatography and reverse-phase high performance liquid chromatography(RP-HPLC), were used to isolate the ACE inhibition peptides. The amino acid sequences of the peptides were identified as Ile-Asn-Asp, Val-Glu-Pro-Gly and Leu-Ala-Asp-Glu-Phe. The IC_(50) values of the purified peptides for ACE inhibition activity were 34.72 μmol L^(-1), 20.55 μmol L^(-1) and 22.77 μmol L^(-1), respectively. These results suggested that S. nudus proteins contain specific peptides that can be released by enzymatic hydrolysis. This study may provide an experimental basis for further systematic research, rational development and clinical utilization of sandworm resources.

Effects of angiotensin converting enzyme inhibitor,angio-tensin II type I receptor blocker and their combination on postinfarcted ventricular remodeling in rats

Background Transforming growth factor （TGF） β1-Smads signal plays an important role in cardiac remodeling following myocardial infarction （MI）. In addition, both angiotensin converting enzyme inhibitor （ACEI） and angiotensin Ⅱ type Ⅰ receptor blocker （ARB） can effectively prevent left ventricular remodeling. The current study focused on whether the combination of ACEI and ARB is more beneficial for preventing ventricular remodeling and whether Smad proteins mediate this beneficial effect. Methods MI was induced by ligating the left anterior descending coronary artery in rats. Twenty-four hours after ligation, the survived rats were randomly divided into five groups and treated for 8 weeks： placebo group, ACEI group （benazepril 10 mg · kg^-1· d^-1）, ARB group （irbesartan 50mg · kg^-1· d^-1）, ACEI＋ARB group （benazepril 10 mg · kg^-1· d^-1＋irbesartan 50 mg · kg^-1· d^-1） and control group （sham-operated rats）. After 8 weeks, we examined the following indexes： the ratio of ventricular weight to body weight （VW/BW）, left ventricular end diastolic dimension （LVDd）, ejection fraction （EF）, fractional shortening （FS）, ratio of E-wave to A-wave velocity, collagen of noninfarcted zone, the mRNA expression of TGFβ1, Smad 2, and Smad 3 by RT-PCR in noninfarcted zone, the protein expression of Smad 2 and Smad 3 in noninfarcted zone by Western blot. Results VW/BW significantly increased in the placebo groups compared with that in the control group （P〈0.01）. This increase was limited in ACEI, ARB, and combined groups （P〈0.01 compared with placebo group）. There was no significant difference among the three actively treated groups. Collagen was increased in placebo group （5.68±0.5）% compared with that in control group （P〈0.01）. ACEI, ARB and combined treatment attenuated this increase of collagen [（4.3 ± 0.5）%, （3.5 ± 0.5）%, （3.2± 0.4）%] in comparison with that in placebo group （P〈0.01 respectively）. Combined treatment showed more significant effect on collagen deposition. EF and FS significantly decreased, LVDd and E/A significantly increased in placebo group compared with that in control group （P〈0.01 respectively）. ACEI, ARB and combined treatment ameliorated these indexes （P〈0.01 compared with placebo group）. The mRNA expression of TGFβ1, Smad 2, and Smad 3 （0.700±0.045, 0.959±0.037 and 0.850±0.051） increased in placebo group compared with that in control group （P〈0.01）. ACEI, ARB and combined treatment normalized the increase （P〈0.01）. Furthermore, ARB and combined treatment proved to be more effective in decreasing TGF β1 and Smad mRNA expression than ACEI treatment （P〈0.01）. The expression of Smad 2 and Smad 3 protein increased in placebo group compared with that in control group （P〈0.01）. ACEI, ARB and combined treatment normalized the increase （P〈0.01）. Furthermore, ARB and combined treatment proved to be more effective than ACEI alone （P〈0.01）.Conclusions TGFβ1-Smads signal activation is correlated With ventricular remodeling following MI. ACEI and ARB treatment prevents ventricular remodeling by inhibiting expression of Smad 2 and Smad 3. ARB and combined treatment are more effective than ACEI alone.