Angiotensin-converting enzyme 2 alleviates liver fibrosis through the renin-angiotensin system

The present letter to the editor is related to the study titled‘Angiotensin-converting enzyme 2 improves liver fibrosis in mice by regulating autophagy of hepatic stellate cells’.Angiotensin-converting enzyme 2 can alleviate liver fibrosis by regulating autophagy of hepatic stellate cells and affecting the renin-angiotensin system.

Hepatic angiotensin-converting enzyme 2 expression in metabolic dysfunction-associated steatotic liver disease and in patients with fatal COVID-19

BACKGROUND Metabolic dysfunction-associated steatotic liver disease(MASLD),characterised by hepatic lipid accumulation,causes inflammation and oxidative stress accompanied by cell damage and fibrosis.Liver injury(LI)is also frequently reported in patients hospitalised with coronavirus disease 2019(COVID-19),while preexisting MASLD increases the risk of LI and the development of COVID-19-associated cholangiopathy.Mechanisms of injury at the cellular level remain unclear,but it may be significant that severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)which causes COVID-19,uses angiotensin-converting expression enzyme 2(ACE2),a key regulator of the‘anti-inflammatory’arm of the renin-angiotensin system,for viral attachment and host cell invasion.AIM To determine if hepatic ACE2 levels are altered during progression of MASLD and in patients who died with severe COVID-19.METHODS ACE2 protein levels and localisation,and histological fibrosis and lipid droplet accumulation as markers of MASLD were determined in formalin-fixed liver tissue sections across the MASLD pathological spectrum(isolated hepatocellular steatosis,metabolic dysfunction-associated steatohepatitis(MASH)+/-fibrosis,end-stage cirrhosis)and in post-mortem tissues from patients who had died with severe COVID-19,using ACE2 immunohistochemistry and haematoxylin and eosin and picrosirius red staining of total collagen and lipid droplet areas,followed by quantification using machine learning-based image pixel classifiers.RESULTS ACE2 staining is primarily intracellular and concentrated in the cytoplasm of centrilobular hepatocytes and apical membranes of bile duct cholangiocytes.Strikingly,ACE2 protein levels are elevated in non-fibrotic MASH compared to healthy controls but not in the progression to MASH with fibrosis and in cirrhosis.ACE2 protein levels and histological fibrosis are not associated,but ACE2 and liver lipid droplet content are significantly correlated across the MASLD spectrum.Hepatic ACE2 levels are also increased in COVID-19 patients,especially those showing evidence of LI,but are not correlated with the presence of SARS-CoV-2 virus in the liver.However,there is a clear association between the hepatic lipid droplet content and the presence of the virus,suggesting a possible functional link.CONCLUSION Hepatic ACE2 levels were elevated in nonfibrotic MASH and COVID-19 patients with LI,while lipid accumulation may promote intra-hepatic SARS-CoV-2 replication,accelerating MASLD progression and COVID-19-mediated liver damage.

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.

Angiotensin-converting enzyme 2 improves liver fibrosis in mice by regulating autophagy of hepatic stellate cells

BACKGROUND Liver fibrosis is the common pathological process associated with the occurrence and development of various chronic liver diseases.At present,there is still a lack of effective prevention and treatment methods in clinical practice.Hepatic stellate cell(HSC)plays a key role in liver fibrogenesis.In recent years,the study of liver fibrosis targeting HSC autophagy has become a hot spot in this research field.Angiotensin-converting enzyme 2(ACE2)is a key negative regulator of reninangiotensin system,and its specific molecular mechanism on autophagy and liver fibrosis needs to be further explored.AIM To investigate the effect of ACE2 on hepatic fibrosis in mice by regulating HSC autophagy through the Adenosine monophosphate activates protein kinases(AMPK)/mammalian target of rapamycin(mTOR)pathway.METHODS Overexpression of ACE2 in a mouse liver fibrosis model was induced by injection of liver-specific recombinant adeno-associated virus ACE2 vector(rAAV2/8-ACE2).The degree of liver fibrosis was assessed by histopathological staining and the biomarkers in mouse serum were measured by Luminex multifactor analysis.The number of apoptotic HSCs was assessed by terminal deoxynucleoitidyl transferase-mediated dUTP nick-end labeling(TUNEL)and immunofluorescence staining.Transmission electron microscopy was used to identify the changes in the number of HSC autophagosomes.The effect of ACE2 overexpression on Wu Y et al.ACE2 improves liver fibrosis through autophagy WJG https://www.wjgnet.com 4976 September 7,2023 Volume 29 Issue 33 autophagy-related proteins was evaluated by multicolor immunofluorescence staining.The expression of autophagy-related indicators and AMPK pathway-related proteins was measured by western blotting.RESULTS A mouse model of liver fibrosis was successfully established after 8 wk of intraperitoneal injection of carbon tetrachloride(CCl4).rAAV2/8-ACE2 administration reduced collagen deposition and alleviated the degree of liver fibrosis in mice.The serum levels of platelet-derived growth factor,angiopoietin-2,vascular endothelial growth factor and angiotensin II were decreased,while the levels of interleukin(IL)-10 and angiotensin-(1-7)were increased in the rAAV2/8-ACE2 group.In addition,the expression of alpha-smooth muscle actin,fibronectin,and CD31 was down-regulated in the rAAV2/8-ACE2 group.TUNEL and immunofluorescence staining showed that rAAV2/8-ACE2 injection increased HSC apoptosis.Moreover,rAAV2/8-ACE2 injection notably decreased the number of autophagosomes and the expression of autophagy-related proteins(LC3I,LC3II,Beclin-1),and affected the expression of AMPK pathway-related proteins(AMPK,p-AMPK,p-mTOR).CONCLUSION ACE2 overexpression can inhibit HSC activation and promote cell apoptosis by regulating HSC autophagy through the AMPK/mTOR pathway,thereby alleviating liver fibrosis and hepatic sinusoidal remodeling.

New perspectives on angiotensin-converting enzyme 2 and its related diseases

Since the worldwide outbreak of coronavirus disease 2019,angiotensin-converting enzyme 2(ACE2)has received widespread attention as the cell receptor of the severe acute respiratory syndrome coronavirus 2 virus.At the same time,as a key enzyme in the renin-angiotensin-system,ACE2 is considered to be an endogenous negative regulator of vasoconstriction,proliferation,fibrosis,and proinflammation caused by the ACE-angiotensin II-angiotensin type 1 receptor axis.ACE2 is now implicated as being closely connected to diabetes,cardiovascular,kidney,and lung diseases,and so on.This review covers the available information on the host factors regulating ACE2 and discusses its role in a variety of pathophysiological conditions in animal models and humans.

Angiotensin-converting enzyme 2 connects COVID-19 with cancer and cancer immunotherapy

The coronavirus disease 2019(COVID-19)pandemic caused by severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)has resulted in more than two million deaths.Underlying diseases,including cancer,are high-risk factors for severe COVID-19 outcomes.Angiotensin-converting enzyme 2(ACE2),as a SARS-CoV-2 host cell receptor,plays a crucial role in SARS-CoV-2 invading human cells.ACE2 also has significant associations with cancer.Recent studies showed that ACE2 was inversely correlated with the activities of multiple oncogenic pathways and tumor progression phenotypes,and was positively correlated with antitumor immune response and survival prognosis in diverse cancers,suggesting a potential protective role of ACE2 in cancer progression.Positive expression of ACE2 is also correlated with programmed death-ligand 1(PD-L1)in cancer.The positive associations of ACE2 expression with antitumor immune signatures and PD-L1 expression indicate that ACE2 expression is a positive predictor for the response to immune checkpoint inhibitors(ICIs).This was evidenced in multiple cancer cohorts treated with ICIs.Thus,ACE2 may build potential connections between COVID-19 and cancer and cancer immunotherapy.The potential connections suggest that ACE2 inhibitors may not be a good option for treating COVID-19 patients with cancer,particularly in cancer patients who are receiving immunotherapy.Furthermore,the relationships between ACE2,COVID-19,and cancer are worth confirming by more experimental and clinical data,considering that many cancer patients are at high risk for COVID-19.

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.

Role of renin-angiotensin system/angiotensin converting enzyme-2 mechanism and enhanced COVID-19 susceptibility in type 2 diabetes mellitus

Coronavirus disease 2019(COVID-19)is a disease that caused a global pandemic and is caused by infection of severe acute respiratory syndrome coronavirus 2 virus.It has affected over 768 million people worldwide,resulting in approx-imately 6900000 deaths.High-risk groups,identified by the Centers for Disease Control and Prevention,include individuals with conditions like type 2 diabetes mellitus(T2DM),obesity,chronic lung disease,serious heart conditions,and chronic kidney disease.Research indicates that those with T2DM face a hei-ghtened susceptibility to COVID-19 and increased mortality compared to non-diabetic individuals.Examining the renin-angiotensin system(RAS),a vital regulator of blood pressure and pulmonary stability,reveals the significance of the angiotensin-converting enzyme(ACE)and ACE2 enzymes.ACE converts angiotensin-I to the vasoconstrictor angiotensin-II,while ACE2 counters this by converting angiotensin-II to angiotensin 1-7,a vasodilator.Reduced ACE2 exp-ression,common in diabetes,intensifies RAS activity,contributing to conditions like inflammation and fibrosis.Although ACE inhibitors and angiotensin receptor blockers can be therapeutically beneficial by increasing ACE2 levels,concerns arise regarding the potential elevation of ACE2 receptors on cell membranes,potentially facilitating COVID-19 entry.This review explored the role of the RAS/ACE2 mechanism in amplifying severe acute respiratory syndrome cor-onavirus 2 infection and associated complications in T2DM.Potential treatment strategies,including recombinant human ACE2 therapy,broad-spectrum antiviral drugs,and epigenetic signature detection,are discussed as promising avenues in the battle against this pandemic.

Double enzyme mimetic activities of multifunctional Ag nanoparticle-decorated Co_(3)V_(2)O_(8)hollow hexagonal prismatic pencils for application in colorimetric sensors and disinfection

Since the catalytic activity of most nanozymes is still far lower than the corresponding natural enzymes,there is urgent need to discover novel highly efficient enzyme-like materials.In this work,Co_(3)V_(2)O_(8)with hollow hexagonal prismatic pencil structures were prepared as novel artificial enzyme mimics.They were then decorated by photo-depositing Ag nanoparticles(Ag NPs)on the surface to further improve its catalytic activities.The Ag NPs decorated Co_(3)V_(2)O_(8)(ACVPs)showed both excellent oxidase-and peroxidase-like catalytic activities.They can oxidize the colorless 3,3’,5,5’-tetramethylbenzidine rapidly to induce a blue change.The enhanced enzyme mimetic activities can be attributed to the surface plasma resonance(SPR)effect of Ag NPs as well as the synergistic catalytic effect between Ag NPs and Co_(3)V_(2)O_(8),accelerating electron transfer and promoting the catalytic process.ACVPs were applied in constructing a colorimetric sensor,validating the occurrence of the Fenton reaction,and disinfection,presenting favorable catalytic performance.The enzyme-like catalytic mechanism was studied,indicating the chief role of⋅O_(2)-radicals in the catalytic process.This work not only discovers a novel functional material with double enzyme mimetic activity but also provides a new insight into exploiting artificial enzyme mimics with highly efficient catalytic ability.

Angiotensin-converting enzyme 2 activation protects against pulmonary arterial hypertension through improving early endothelial function and mediating cytokines levels

Background Increasing evidences indicate that an activated renin-angiotensin system （RAS） causes an imbalance between the vasoconstrictive and vasodilator mechanisms involving the pulmonary circulation leading to the development of pulmonary arterial hypertension （PAH）. Angiotensin-converting enzyme 2 （ACE2）, a primary component of the vasoprotective axis in RAS, is recently identified that it has regulatory actions in lung pathophysiology, but the mechanism in these processes is uncertain yet. Methods Severe PAH was induced by monocrotaline injection one week following pneumonectomy in rats. The activation of ACE2 by continuous injection of resorcinolnaphthalein was studied by real time-polymerase chain reaction （RT-PCR）, Western blotting and fluorogenic peptide assay. Endothelial functions were evaluated by the response to acetylcholine and cytokines were measured by RT-PCR seven days after monocrotaline injection. The PAH-related hemodynamics and pathological changes were examined at day 21 when severe PAH was completely established. Results Resorcinolnaphthalein caused significant activation of ACE2 in both normal and diseased rats in 7 days after treatment. The pulmonary arterial pressure （PAP） started to increase at least 7 days after monocrotaline injection, and the rats developed severe PAH in 21 days with high PAP, right ventricular hypertrophy and neointimal formation. Treatment with resorcinolnaphthalein prevented these features. Resorcinolnaphthalein caused an improved endothelia-dependent vasorelaxation and decrease in proinflammatory cytokines （tumor necrosis factor （TNF）-a, monocyte chemoattractant protein-1 （MCP-1）, interleukin （IL）-6） and increase in anti-inflammatory cytokine IL-10 in the early stage of the pathogenesis. Conclusions These results demonstrated that activation of ACE2 by continuous injection of resorcinolnaphthalein prevented the development of PAH through improving early endothelial dysfunction and mediating the level of proinflammatory and anti-inflammatory cytokines.

Angiotensin-converting enzyme 2(ACE2):SARS-CoV-2 receptor and RAS modulator

The coronavirus disease 2019(COVID-19)outbreak is caused by severe acute respiratory syndrome coronavirus 2(SARS-CoV-2).Angiotensin-converting enzyme 2(ACE2)was rapidly identified as the critical functional receptor for SARS-CoV-2.ACE2 is well-known as a counter-regulator of the renin-angiotensin system(RAS)and plays a key role in the cardiovascular system.Given that ACE2 functions as both a SARS-CoV-2 receptor and a RAS modulator,the treatment for COVID-19 presents a dilemma of how to limit virus entry but protect ACE2 physiological functions.Thus,an in-depth summary of the recent progress of ACE2 research and its relationship to the virus is urgently needed to provide possible solution to the dilemma.Here,we summarize the complexity and interplay between the coronavirus,ACE2 and RAS(including anti-RAS drugs).We propose five novel working modes for functional receptor for SARS-CoV-2 infection and the routes of ACE2-mediated virus entering host cells,as well as its regulatory mechanism.For the controversy of anti-RAS drugs application,we also give theoretical analysis and discussed for drug application.These will contribute to a deeper understanding of the complex mechanisms of underlying the relationship between the virus and ACE2,and provide guidance for virus intervention strategies.

Polymorphisms of angiotensin-converting enzyme 2 gene associated with magnitude of left ventricular hypertrophy in male patients with hypertrophic cardiomyopathy

Background Even carrying an identical gene mutation, inter- and intra-family variations have been noticed worldwide in the presence and the severity of left ventricular hypertrophy and sudden death in patients with hypertrophic cardiomyopathy （HCM）. Modifier genes may contribute to the diversity. Angiotensin-converting enzyme 2 （ACE2） gene has been established to be associated with parameters of left ventricular hypertrophy in community based male subjects. The objective of the present study was to investigate the association of ACE2 gene polymorphisms with the phenotype of HCM. Methods A total of 261 consecutive HCM patients and 609 healthy controls were enrolled into this study. The polymorphism of rs2106809 and rs6632677 were genotyped by polymerase chain reaction-restriction fragment length polymorphism （PCR-RFLP） and confirmed by sequencing. Logistic regression model and multivariate analysis were used to determine the odds ratio （OR） and 95% confidence intervals （CO of variations of ACE2 for HCM. Results The T allele of rs2106809 and C allele of rs6632677 conferred increasing risk for HCM （OR 1.34, 95%C/ 1.01-1.77, P=0.04; OR 1.11, 95%C/ 1.03-1.21, P=0.002, respectively）, and the 2 single nucleotide polymorphisms （SNPs） were in strong linkage disequilibrium （LD）, the TC haplotype was independently associated with a higher OR for HCM （OR=1.59, 95%C/1.21-1.87） after adjusted for conventional risk factors. And the risk alleles were associated with thicker interventricular septal thickness of HCM （（20.0±6.3） mm vs （17.9±5.5） mm, P=0.03 and （21.3±5.9） mm vs （17.9±5.8） mm, P=0.04, respectively）. No association was found between the two polymorphisms with female patients with HCM. Conclusion Minor alleles of ACE2 gene might be the genetic modifier for the magnitude of left ventricular hypertrophy in male patients with HCM.

Role and mechanism of angiotensin-converting enzyme 2 in acute lung injury in coronavirus disease 2019

Coronavirus disease 2019 is a major threat to public health globally.Though its pathogenesis has not been fully elucidated,angiotensin-converting enzyme 2(ACE2)has been recently identified as a receptor for the entry of severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)into the cell.Here,we aimed to clarify the potential role of ACE2 in SARS-CoV-2-induced acute lung injury and its underlying mechanism.As a receptor for coronavirus,ACE2 mediates the entry of SARS-CoV-2 into cells in a similar way as for severe acute respiratory syndrome coronavirus(SARS-CoV).The high binding affinity of SARS-CoV-2 to ACE2 correlates with its efficient spread among humans.On the other hand,ACE2 negatively regulates the renin-angiotensinaldosterone system(RAAS)primarily by converting angiotensinⅡto angiotensin 1-7.which exerts a beneficial effect on coronavirus-induced acute lung injury.Human recombinant ACE2 has been considered as a potential therapy for SARS-CoV-2 by blocking virus entry and redressing the imbalance of RAAS in SARS-CoV-2 infection.The level of ACE2 expression can be upregulated by treatment with an ACE inhibitor(ACEI)or angiotensinⅡtype 1 receptor blocker(ARB).To date,no evidence shows that ACEIs or ARBs increase the susceptibility and mortality of patients infected with SARS-CoV-2,and hence,it is not advisable to discontinue such drugs in patients with cardiovascular disease.

Sequence difference of angiotensin-converting enzyme 2 between nonhuman primates affects its binding-affinity with SARS-CoV-2 S receptor binding domain

Severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)has caused many deaths and contributed to a tremendous public health concern worldwide since 2020.Angiotensin-converting enzyme 2(ACE2)binds to the SARS-CoV-2 virus as a receptor.The challenge of different nonhuman primate(NHP)species by SARSCoV-2 virus demonstrated different effects on virus replication and disease pathology.This study characterizes differences between host ACE2 sequences of three NHP species:Macaca mulatta,Macaca fascicularis,and Chlorocebus sabaeus.In addition,the binding affinity between the ACE2 ectodomain and the SARS-CoV-2 S receptor-binding domain(RBD)was analyzed.Variation of ACE2 sequence among NHP species and the binding affinity may account for different susceptibility and responses to SARS-CoV-2 infection.

Impact of angiotensin-converting enzyme inhibitors or angiotensin receptor blockers on the mortality in sepsis: A meta-analysis

BACKGROUND The effect of angiotensin-converting enzyme inhibitors(ACEIs)or angiotensin receptor blockers(ARBs)on the mortality of patients with sepsis is not well characterized.AIM To elucidate the association between prior ACEI or ARB exposure and mortality in sepsis.METHODS The PubMed,EMBASE,Web of Science,and Cochrane Library databases were searched for all studies of premorbid ACEI or ARB use and sepsis mortality until November 302019.Two reviewers independently assessed,selected,and ab-stracted data from studies reporting ACEIs or ARBs,sepsis,and mortality.The primary extracted data consisted of premorbid ACEI or ARB exposure,mortality,and general patient data.Two reviewers independently assessed the risk of bias and quality of evidence.RESULTS A total of six studies comprising 281238 patients with sepsis,including 49799 cases with premorbid ACEI or ARB exposure were eligible for analysis.Pre-morbid ACEIs or ARBs exposure decreased the 30-d mortality in patients with sepsis.Moreover,the use of ACEIs or ARBs was associated with approximately a 6%decreased risk of 30-d mortality.CONCLUSION The results of this systematic review suggest that ACEI or ARB exposure prior to sepsis may be associated with reduced mortality.Further high-quality cohort studies and molecular mechanism experiments are required to confirm our results.

Relationship between polymorphism of angiotensin-converting enzyme 2 gene and the risk factor of essential hypertension with complicated stroke

Background Essential hypertension （EH） is considered to be one of the most important risk factor of ischemic stroke. Studies about risk factors in the patients are meaningful in early forecast and effective prevention of the onset of stroke. Renin-angiotensin-aldosterone system plays an important role in the regulation of blood pressure and the development of stroke, while recent studies have found that the angiotensin-converting enzyme 2 （ACE2） may be a reversal agent for the development and progression of ischemic stroke. Methods The ACE2 gene was measured in 139 EH patients with ischemic stroke using polymerase chain reaction （PCR） and restriction fragment length polymorphism （PCR-RFLP） tests. Detailed and complete clinical and biochemical data were collected, including pulse pressure, hsCRP, IMT, HDL-C and uric acid levels. Study the correlation between angiotensin-converting enzyme 2 gene and the risk factor for onset of ischemic stroke in EH patients. Results Pulse pressure, hsCRP, IMT and uric acid levels had a positive correlation with on- set of ischemic stroke in EH patients. Among male patients, pulse pressure, hsCRP, IMT and HDL-C were higher in patients carrying A allele than B allele （P 〈 0.05）. While these factors were different in female patients carrying different genotypes in which A.A allele were highest. Patients with various genotypes showed different uric acid levels but showed no significant difference. Conclusion Among EH patients with complicated ischemic stroke, those carrying the A/AA allele show high level of risk factors and is likely to have the susceptibility of recurrence of stroke.

Increasing angiotensin-converting enzyme(ACE)2/ACE axes ratio alleviates early pulmonary vascular remodeling in a porcine model of acute pulmonary embolism with cardiac arrest

BACKGROUND:Acute pulmonary embolism(APE)with cardiac arrest(CA)is characterized by high mortality in emergency due to pulmonary arterial hypertension(PAH).This study aims to determine whether early pulmonary artery remodeling occurs in PAH caused by massive APE with CA and the protective effects of increasing angiotensin-converting enzyme(ACE)2-angiotensin(Ang)(1-7)-Mas receptor axis and ACE-Ang II-Ang II type 1 receptor(AT1)axis(ACE2/ACE axes)ratio on pulmonary artery lesion after return of spontaneous circulation(ROSC).METHODS:To establish a porcine massive APE with CA model,autologous thrombus was injected into the external jugular vein until mean arterial pressure dropped below 30 mmHg(1 mmHg=0.133 kPa).Cardiopulmonary resuscitation and thrombolysis were delivered to regain spontaneous circulation.Pigs were divided into four groups of five pigs each:control group,APE-CA group,ROSC-saline group,and ROSC-captopril group,to examine the endothelial pathological changes and expression of ACE2/ACE axes in pulmonary artery with or without captopril.RESULTS:Histological analysis of samples from the APE-CA and ROSC-saline groups showed that pulmonary arterioles were almost completely occluded by accumulated endothelial cells.Western blotting analysis revealed a decrease in the pulmonary arterial ACE2/ACE axes ratio and increases in angiopoietin-2/angiopoietin-1 ratio and expression of vascular endothelial growth factor(VEGF)in the APE-CA group compared with the control group.Captopril significantly suppressed the activation of angiopoietin-2/angiopoietin-1 and VEGF in plexiform lesions formed by proliferative endothelial cells after ROSC.Captopril also alleviated endothelial cell apoptosis by increasing the B-cell lymphoma-2(Bcl-2)/Bcl-2-associated X(Bax)ratio and decreasing cleaved caspase-3 expression.CONCLUSION:Increasing the ACE2/ACE axes ratio may ameliorate pulmonary arterial remodeling by inhibiting the apoptosis and proliferation of endothelial cells after ROSC induced by APE.

Plasma Levels of Angiotensin-Converting Enzymes 1 and 2 and <i>AGTR</i>2 (T1247G and A5235G) Gene Polymorphisms Are Associated to Breast Cancer Progression

Background: Breast cancer is the most common type of cancer among women. Diagnosed and treated timely, patients may have good prognostics. In Brazil, in 2012, the estimate of new cases was 52,680 and the number of registered deaths in 2012 was 12,852. The Renin-Angiotensin System (RAS) is known for its role in arterial hypertension and in other cardiovascular diseases. Angiotensin-Converting Enzyme 2 (ACE2) is the key to Ang-(1-7) formation, and counterbalances the ACE1/AngII/AGTR1 axis actions. RAS components have complex interactions with different tissues and their actions are not restricted to the cardiovascular system. Recently, the RAS has been associated with different types of cancers and in particular with gynecological cancers. Objectives: Our aim is to investigate possible associations between allelic distribution of two genetic polymorphisms in the AGTR2 receptor with ACEs 1 and 2 plasma levels among women with breast cancer. Patients and Methods: Patients with breast cancer were genotyped for two polymorphisms of the AGTR2 (T1247G and A5235G). Genotyping assays (TaqMan) were performed with genomic DNA extracted from blood cells. ACEs plasma level measurements were conducted in women from the breast-cancer group (N = 53). ACEs were measured in the plasma of these patients using ELISA kits. Results: SNPs genotype distribution is correlated with ACEs plasma levels. ACEs plasma levels are also correlated with clinical variables and ACE2 high levels are associated with better prognostics. Conclusions: Changes in circulating levels of ECA1/AngII ECA2/ Ang-(1-7) determine the magnitude of the inflammatory response that an individual can trigger and the variation in ACE 1 and 2 plasma level measurements in the blood of breast cancer patients suggests an association with the process of mammary carcinogenesis. Thus, the RAS may be associated with the process of mammary carcinogenesis by both genotypic variations of RAS components and by circulating levels of ACEs.

AT1a Receptor Has Interacted with Angiotensin-converting Enzymes 2 mRNA Expression in Mouse Brainstem

Objectives To examine in vivo interactions between angiotensin Ⅱ （Ang Ⅱ ） AT1 a receptor （AT1 aR）, angiotensin-converting enzymes （ACE） and ACE2 using small hairpin RNA （shRNA） gene-silencing methods in mice brainstem nucleus tractus solitarius （NTS）. Methods C57BL mice （n = 8 ） were used as animal model. Method of micro-injection in the nucleus of NTS was adopted. After ten days, mice were killed and their brain tissue were fixed and sectioned. The expression levels of AT1 aR, ACE and ACE2 mRNA at both sides of NTS were examined by in situ hybridization. Based on compared t-test, the changing for mRNA expression was examined. Results After the expression of ATlaR mRNA was significantly inhibited （61.6% ± 6.8% ） by ATlaR-shRNA, it was associated with decreases in ACE2 mRNA expression from （ 1.05 ± 0. 12） μCi/mg to （0. 74 ± 0.09 ） μCi/mg （ 29.0% ± 14. 5% , P 〈 0. 01 ） on the same side of the brainstem. ACE mRNA expression was consistent at both sides （ 0. 50 μCi/mg ± 0. 09μCi/mg and 0. 53 μCi/mg ± 0. 08 μCi/mg）, with insignificant difference （ P 〉 0. 05 ）. Conclusions The gene silencing result showed that there were interactions between brainstem AT1 aR and ACE2. ACE mRNA expression was not altered by RNA interference treatment at AT1 aR.

Timosaponin AⅢ induces drug-metabolizing enzymes by activating constitutive androstane receptor (CAR) via dephosphorylation of the EGFR signaling pathway

The current study aimed to assess the effect of timosaponin AⅢ(T-AⅢ)on drug-metabolizing enzymes during anticancer therapy.The in vivo experiments were conducted on nude and ICR mice.Following a 24-day administration of T-AⅢ,the nude mice exhibited an induction of CYP2B10,MDR1,and CYP3A11 expression in the liver tissues.In the ICR mice,the expression levels of CYP2B10 and MDR1 increased after a three-day T-AⅢ administration.The in vitro assessments with HepG2 cells revealed that T-AⅢ induced the expression of CYP2B6,MDR1,and CYP3A4,along with constitutive androstane receptor(CAR)activation.Treatment with CAR siRNA reversed the T-AⅢ-induced increases in CYP2B6 and CYP3A4 expression.Furthermore,other CAR target genes also showed a significant increase in the expression.The up-regulation of murine CAR was observed in the liver tissues of both nude and ICR mice.Subsequent findings demonstrated that T-AⅢ activated CAR by inhibiting ERK1/2 phosphorylation,with this effect being partially reversed by the ERK activator t-BHQ.Inhibition of the ERK1/2 signaling pathway was also observed in vivo.Additionally,T-AⅢ inhibited the phosphorylation of EGFR at Tyr1173 and Tyr845,and suppressed EGF-induced phosphorylation of EGFR,ERK,and CAR.In the nude mice,T-AⅢ also inhibited EGFR phosphorylation.These results collectively indicate that T-AⅢ is a novel CAR activator through inhibition of the EGFR pathway.