Angiotensin-converting Enzyme Research Articles

Epidemiology of paediatric chronic heart failure in Germany-A population-based analysis.

Paediatric chronic heart failure (CHF) is associated with significant morbidity. The aim of this study was to describe paediatric CHF epidemiology in Germany. This is a retrospective cross-sectional analysis of anonymized healthcare claims data in the InGef database. This database includes longitudinal data from a representative sample of the German population of approximately 4.8 million insured members. We included individuals <18years from 2016 to 2021. CHF was defined by ≥2 diagnoses in different quarters of the year as inpatient or outpatient, using ICD-10-GM codes I50.- or P29.0. The number of eligible children in the database was 674462 in 2016 and 660692 in 2021. Prevalence of CHF per 100000 children was 20.6 [95% confidence interval (CI), 17.3-24.3] in 2016 and 19.4 (95% CI, 16.2 to 23.0) in 2021. Incidence per 100000 children was 9.6 (95% CI, 7.4 to 12.3) in 2016 and 7.6 (95% CI, 5.6 to 10.0) in 2021 for newly diagnosed CHF. All-cause hospitalizations occurred in 47.3% to 57.7% of children with CHF per year. Up to 6.3% of children with CHF were hospitalized, coded primarily for heart failure. Mortality of children with CHF was <5 death per year in the studied population. In 128 children with CHF in 2021, the most common ICD-coded comorbidities were congenital malformations of cardiac septa (57.8%), atrial septal defect (44.5%), congenital malformations of the great arteries (43.0%) and ventricular septal defect (32.0%). Coded treatment modalities for paediatric CHF in 2021 included angiotensin-converting enzyme inhibitors or angiotensin II type 1 receptor blockers (18.8%), beta-blockers (17.2%), mineralocorticoid receptor antagonists (14.8%) and surgical procedures (13.3%). This representative cohort study reveals a relatively high incidence proportion. Approximately half of the children with CHF are hospitalized annually while mortality is low.

Shedding light on the cellular mechanisms involved in the combined adverse effects of fine particulate matter and SARS-CoV-2 on human lung cells

Airborne pathogens represent a topic of scientific relevance, especially considering the recent COVID-19 pandemic. Air pollution, and particulate matter (PM) in particular, has been proposed as a possible risk factor for the onset and spread of pathogen-driven respiratory diseases. Regarding SARS-CoV-2 infection, exposure to fine PM (PM2.5, particles with an aerodynamic diameter < 2.5 μm) has been associated with increased incidence of the COVID-19 disease.To provide useful insights into the mechanisms through which PM might be involved in infection, we exposed human lung cells (A549) to PM2.5 and SARS-CoV-2, to evaluate the toxicological properties and the molecular pathways activated when airborne particles are combined with viral particles. Winter PM2.5 was collected in a metropolitan urban area and its physico-chemical composition was analyzed. A549 cells were exposed to SARS-CoV-2 concomitantly or after pre-treatment with PM2.5. Inflammation, oxidative stress and xenobiotic metabolism were the main pathways investigated. Results showed that after 72 h of exposure PM2.5 significantly increased the expression of the angiotensin-converting enzyme 2 (ACE2) receptor, which is one of the keys used by the virus to infect host cells. We also analyzed the endosomal route in the process of internalization, by studying the expression of RAB5 and RAB7. The results show that in cells pre-activated with PM and then exposed to SARS-CoV-2, RAB5 expression is significantly increased. The activation of the inflammatory process was then studied. Our findings show an increase of pro-inflammatory markers (NF-kB and IL-8) in cells pre-activated with PM for 72 h and subsequently exposed to the virus for a further 24 h, further demonstrating that the interaction between PM and SARS-CoV-2 determines the severity of the inflammatory responses in lung epithelial cells. In conclusion, the study provides mechanistic biological evidence of PM contribution to the onset and progression of viral respiratory diseases in exposed populations.

Antihypertensive drug-associated adverse events in osteoarthritis: a study of a large real-world sample based on the FAERS database.

Hypertension is a common complication in patients with osteoarthritis (OA). There is increasing interest in the relationship between hypertension and OA. However, hypertension has been reported to negatively affect symptoms and quality of life in patients with OA. Therefore, treating hypertension is crucial for patients with OA. However, there is a lack of real-world studies on the effects of medications for treating hypertension on OA. Data from the FAERS database from January 2004 to December 2023 were extracted for disproportionality analyses, and proportional reporting ratios (PRRs) were used to assess the association between medications for hypertension and all types of arthritis. Adverse event signals were identified and determined using reporting odds ratios (RORs) Adverse event signals were considered to have occurred if a drug-induced adverse event was recorded more than or equal to 3 and the lower limit of the ROR confidence interval was more than 1. We selected five classes of drugs including, calcium channel blockers (CCBs), angiotensin converting enzyme inhibitors (ACEIs), angiotensin receptor blockers (ARBs), thiazide diuretics and β-blockers and representative drugs were analysed for osteoarthritis-related adverse reactions, and age and gender subgroups were analysed for drugs of significance. We also analysed the occurrence of AEs in relation to time using the Weibull distribution. In terms of overall data, we found significant OA adverse reaction signals only for ARBs among the five drug classes.ARB AEs for spinal osteoarthritis (ROR 4.64, 95% CI 3.62-5.94), osteoarthritis (ROR 3.24 95% CI 2.82-3.72) and gouty arthritis (ROR 3.27 95% CI 1.22-8.75) were the three adverse reactions with the loudest signals. Next, we found that valsartan had strong osteoarthritis adverse reaction signals among the three ARBs, namely, irbesartan, cloxartan, and valsartan. We also analysed age and gender subgroups and found that osteoarthritis signals were strongest in the 18-65 and 65+ population, while females seem to be more prone to valsartan-related OA AEs. ARBs, especially valsartan, have significant positive signals for OA AEs. Therefore, ARB drugs, especially valsartan, should be used with caution when treating patients with OA combined with hypertension.

Case report: Reactive granulomatous dermatitis presenting with inguinal erythematous plaques in a patient administered with pravastatin

An identical group of disorders has been called “interstitial granulomatous dermatitis” and “palisaded neutrophilic and granulomatous dermatitis.” In addition, a drug-induced subset of this condition has been named “interstitial granulomatous drug reaction (IGDR).” More recently, “reactive granulomatous dermatitis (RGD)” has been proposed as an umbrella term encompassing these three disorders. A considerable number of RGD cases are associated with systemic conditions, including autoimmune diseases, such as rheumatoid arthritis and systemic lupus erythematosus, inflammatory bowel disease, and malignancies. IGDR has also been shown to be caused by certain medications. We present a case of a 74-year-old Japanese man showing an asymptomatic, well-demarcated erythema eruption on the bilateral inguinal region extending to the lower abdomen and proximal thigh area. He had hyperlipidemia and had been taking pravastatin for 4 years. A biopsy specimen taken from the erythematous lesion revealed infiltration of lymphocytes and histiocytes in the upper and lower dermis. Interstitial infiltrates of histiocytes and lymphocytes were found as they were dispersed between collagen bundles. Immunostaining showed CD68+ macrophages intermingled with CD4+ and CD8+ T cells. Based on the clinical and histologic findings, the eruption was diagnosed as RGD. Because of the possibility of IGDR, pravastatin was stopped. His eruption completely disappeared within 6 months after the discontinuation. The list of drugs that cause RGD includes angiotensin-converting enzyme inhibitors, antihistamines, β-blockers, antidepressants, anticonvulsants, tocilizumab and ustekinumab. In addition, various statins have been reported to induce drug eruptions. The eruption types are mainly eczematous or lichenoid reactions, with psoriasiform or ichthyosiform reactions occurring rarely. There was only one report documenting that RGD occurred in patients administered rosuvastatin, with annular, violaceous plaques distributed on the extremities, proximal trunk and intertriginous areas. Pravastatin induces lichenoid eruption, but RGD has not been documented. Our case suggests that RGD is underestimated as an adverse effect of statins possibly because of its unusual cutaneous manifestations.

Altered kidney distribution and loss of ACE2 into the urine in acute kidney injury.

There are diverse pathophysiological mechanisms involved in acute kidney injury (AKI). Among them, overactivity of the renin-angiotensin system (RAS) has been described. Angiotensin-converting enzyme 2 (ACE2) is a tissue RAS enzyme expressed in the apical border of proximal tubules. Given the important role of ACE2 in the metabolism of angiotensin II, this study aimed to characterize kidney and urinary ACE2 in a mouse model of AKI. Ischemia-reperfusion injury (IRI) was induced in C57BL/6 mice by clamping of the left renal artery followed by removal of the right kidney. In kidneys harvested 48 h after IRI, immunostaining revealed a striking maldistribution of ACE2 including spillage into the tubular lumen and the presence of ACE2-positive luminal casts in the medulla. In cortical membranes, ACE2 protein and enzymatic activity were both markedly reduced (37 ± 4 vs. 100 ± 6 ACE2/β-actin, P = 0.0004, and 96 ± 14 vs. 152 ± 6 RFU/μg protein/h, P = 0.006). In urine, full-length membrane-bound ACE2 protein (100 kDa) was markedly increased (1,120 ± 405 vs. 100 ± 46 ACE2/µg creatinine, P = 0.04), and casts stained for ACE2 were recovered in the urine sediment. In conclusion, in AKI caused by IRI, there is a marked loss of ACE2 from the apical tubular border with deposition of ACE2-positive material in the medulla and increased urinary excretion of full-length membrane-bound ACE2 protein. The deficiency of tubular ACE2 in AKI suggests that provision of this enzyme could have therapeutic applications and that its excretion in the urine may also serve as a diagnostic marker of severe proximal tubular injury.NEW & NOTEWORTHY This study provides novel insights into the distribution of kidney ACE2 in a model of AKI by IRI showing a striking detachment of apical ACE2 from proximal tubules and its loss in urine and urine sediment. The observed deficiency of kidney ACE2 protein and enzymatic activity in severe AKI suggests that administration of forms of this enzyme may mitigate AKI and that urinary ACE2 may serve as a potential biomarker for tubular injury.

ACE2 Knockout Mice Are Resistant to High-Fat Diet-Induced Obesity in an Age-Dependent Manner.

Angiotensin converting enzyme 2 (ACE2) presents pleiotropic actions. It hydrolyzes angiotensin I (AngI) and angiotensin II (AngII) into angiotensin-(1-9) (Ang-(1-9)) and angiotensin-(1-7) (Ang-(1-7)), respectively, as well as participates in tryptophan uptake in the gut and in COVID-19 infection. Our aim was to investigate the metabolic effect of ACE2 deletion in young adults and elderly mice under conditions of high calorie intake. Male C57Bl/6 (WT) and ACE2-deficient (ACE2-/y) mice were analyzed at the age of 6 and 12 months under standard diet (StD) and high-fat diet (HFD). Under StD, ACE2-/y showed lower body weight and fat depots, improved glucose tolerance, enhanced insulin sensitivity, higher adiponectin, and lower leptin levels compared to WT. This difference was even more pronounced after HFD in 6-month-old mice, but, interestingly, it was blunted at the age of 12 months. ACE2-/y presented a decrease in adipocyte diameter and lipolysis, which reflected in the upregulation of lipid metabolism in white adipose tissue through the increased expression of genes involved in lipid regulation. Under HFD, both food intake and total energy expenditure were decreased in 6-month-old ACE2-/y mice, accompanied by an increase in liquid intake, compared to WT mice, fed either StD or HFD. Thus, ACE2-/y mice are less susceptible to HFD-induced obesity in an age-dependent manner, as well as represent an excellent animal model of human lipodystrophy and a tool to investigate new treatments.

Abstract 73: Extracellular vesicles-derived miR-125b-5p/miR-125a-5p promotes hypertension by regulating angiotensin-converting enzyme 2

Therapeutic targeting of non-coding RNAs, particularly microRNA (miRNA), presents an appealing approach in the treatment of chronic diseases such as resistant hypertension. Recently, miRNA have emerged as promising targets for therapeutic intervention, capable of regulating critical genes to provide a suitable solution to the lack of efficacy of current treatments. Our comprehensive miRNA profiling of plasma extracellular vesicles (EV) from DOCA-salt hypertensive mice of both sexes, compared to sham controls, identified two miRNA implicated in salt-sensitive hypertension, namely miR-125b-5p and miR-125a-5p. Our bioinformatic analysis suggests that these miRNA could be involved in angiotensin-converting enzyme 2 (ACE2) downregulation in hypertension. The present study intended to validate ACE2 as a target of miR-125. Quantitative RT-PCR and capillary western analysis of hypothalami from C57BL/6J DOCA+Salt hypertensive male and female mice following 3-weeks of DOCA+Salt treatment (n=5-6 per group, 3-month old), detected a significant decrease in ACE2 mRNA (males: 0.34±0.03 vs. 1.02±0.02; females: 0.65±0.08 vs. 1.01±0.01; P&lt;0.05) and protein (males: 0.17±0.02 vs. 0.31±0.05; females: 0.16±0.03 vs. 0.37±0.07; P&lt;0.05) expression for both sexes. Further investigation in bEND.3 cells treated with different concentrations of Ang-II (0, 10, 100 nM) for 12, 24, and 48 hours, demonstrated a dose-dependent negative correlation between miR-125b-5p (r≈-0.9978) or miR-125a-5p (r≈-1.002) and ACE2 gene expression, independently of time. When treated with miR-125 mimics the cells demonstrated a consistent downregulation of ACE2 protein levels (miR-125b-5p: 0.6±0.1 and miR-125a-5p: 2.0±0.2 vs. control: 2.8±0.3). Conversely, no significant change in ACE2 protein levels was observed with the respective miRNA inhibitors. Using a firefly/Renilla luciferase assay, we further identified ACE2 as a validated primary target for these miRNA. While miR-125b-5p indirectly modulates the expression of the Ace2 gene by targeting important transcription factors like Sp1 and STAT3, our data further elucidate that miR-125b-5p and/or miR-125a-5p directly reduce ACE2 levels by targeting ACE2 3’UTR mRNA. Additional work is warranted to investigate these specific regulatory mechanisms based on cell specificity, physiological conditions, and sex differences.

Abstract P435: PROTEIN KINASE MODULATION IN THE INVESTIGATION OF ANGIOTENSIN-CONVERTING ENZYME AS A SIGNALING PATHWAY.

The Renin-Angiotensin System (RAS) is a hormonal cascade intricately involved in regulating hydro electrolyte homeostasis and blood pressure control. The Angiotensin II peptide (ANGII) is the main and most potent biologically active product within this system, which is produced by the action of Angiotensin Converting Enzyme (ACE) on Angiotensin I. Dysregulation of the RAS is an important factor in the pathogenesis and progression of cardiovascular diseases and diabetes. Furthermore, ACE inhibitors (iECA) havebeen associated with the activation of signaling pathways, thus implicating ACE as a signal transducer molecule. This study aims to elucidate the significance of signaling pathways triggered by ACE and proteins that are differentially regulated when CHO-ECA cells are stimulated with ACE inhibitors. At approximately 80% confluency, the cells were deprived of serum and then stimulated with captopril (1μM) or enalapril (1μM) or vehicle for 2 and 5 minutes (n=10 in each group), to discerning the influence of sulfhydryl and carboxyl radicals. CHO-ECA cells were cultured for Kinase Array assay analysis using the Phospho-kinase Array Kit. This assay demonstrated that some pathways were positively modulated after captopril treatment after 2 minutes (AMPKa1, HSP27, Akt 1/2/3 T308) and after 5 (STATa/b, HSP60, b-Catenin). Some kinases were negatively modulated by captopril treatment (p53, PLC-γ1, Pyk2, eNOS). Conversely, treatment with enalapril modulated proteins differently at both treatment times. Some phospho-protein kinases were positively modulated in 2 minutes, such as PLC γ1, PYK2, and Yes, and others were positively modulated in 5 minutes (EGFR, GSK-3α/β, Lyn, PDGF Rβ, STAT 5a/b, WNK1 and STAT3 S2). The kinases AKT 1/2/3 T308, AKT 1/2/3 S743, CREB, Chk-2, c-Jun, JNK1/2/3, Lck, p38α, STAT3 Y705, β-Catenin were positively modulated in 2 and 5 minutes. The kinases eNOS, ERK1/2, GSK-3β, HSP27, p53 S15, p53 S46, MSK1/2, p70 S6 T389, p70 S6 T421/S424, PRAS40, Src, RSK1/2, RSK1/2/3, STAT1 and HSP60 were negatively modulated at 2 and 5 minutes. In conclusion, our findings augmented the current understanding of kinases modulated by captopril or enalapril, after ACE binding, highlighting the multifaceted role of ACE. Therefore, it can suggest that ACE may be a candidate to act not only as an enzyme but also as a signaling receptor and transducer protein.

Abstract MP15: Macrophage PPARα is essential to increased immune function induced by angiotensin converting enzyme (ACE).

Mice with increased macrophage expression of angiotensin converting enzyme (ACE), called ACE 10/10 mice, have a profound increase of macrophage function in response to diverse immune challenges including tumors, infection, atherosclerosis, and Alzheimer’s disease. ACE 10/10 macrophages are highly efficient in oxidative ATP generation, and they express increased amounts of peroxisome proliferator-activated receptor alpha (PPARα), a transcription factor that controls lipid metabolism. To pinpoint the role of PPARα in increasing macrophage immune function, we used LysM-Cre-LoxP system to generate ACE 10/10 mice selectively lacking macrophage PPARα (A10-PPARα-Cre mice). This reduced macrophage fatty acid metabolism, reduced oxidative metabolism, and lowered macrophage intracellular ATP. Functionally, A10-PPARα-Cre macrophage are impaired in both adaptive and innate immunity. A10-PPARα-Cre mice have larger tumor growth of B16-F10 melanoma, less intratumor macrophages, reduced anti-tumor cytokines, and reduced generation of tumor antigen-specific CD8 + T cells. The mice also have a very attenuated anti-bacterial response to methicillin-resistant Staphylococcus aureus (MRSA) infection, with more severe MRSA tissue colonization in vivo . In addition, increasing ACE expression or adding a PPARα agonist to the human monocytic cell line THP-1 enhances tumor cell cytotoxicity, phagocytosis of bacteria, and bacterial killing. Thus, we find that elevated macrophage PPARα is absolutely required for the increased immunity of ACE 10/10 mice. This may indicate a pathway to increasing human immunity.

Abstract P380: ISG15 is responsible for endothelial inflammation and vascular disfunction induced by Spike protein 1 of SARS-CoV-2.

Introduction: COVID19-associated immunopathology is associated with increased production of interferon (IFN)-alpha (IFNα) and lambda3 (IFNL3). Effects of IFNs are mediated by interferon-stimulated genes (ISGs) and influence expression of angiotensin-converting enzyme 2 (ACE2), the receptor for S-protein (S1P) of SARS-CoV-2. We hypothesized that S1P-induced immune/inflammatory responses in endothelial cells (EC) are mediated via IFNs and may be important in vascular dysfunction associated with hypertension. Methods: Human microvascular ECs (MEC) were stimulated with S1P (1µg/mL), IFNα (100ng/mL) or IFNL3 (100IU/mL). Because ACE2, metalloproteinase domain-17 (ADAM17) and type-II transmembrane serine protease (TMPRSS2) are important for SARS-CoV-2 infection, we used inhibitors of ADAM17 (marimastat), ACE2 (MLN4760), and TMPRSS2 (camostat). Gene and protein expression was investigated by real-time PCR and immunoblotting. Vascular function was assessed in mesenteric arteries from wild-type (WT) normotensive and hypertensive mice and in ISG15KO mice. Results: MEC stimulated with S1P increased expression of IFNα (3-fold), IFNL3 (4-fold) and ISGs (2-fold) (p&lt;0.05). IFNα and IFNλ3 increased protein expression of TMPRSS2 and ADAM17, but not ACE2. MEC exhibited higher responses to IFNα (ISG15: 16-fold) than to IFNL3 (ISG15: 1.7-fold) (p&lt;0.05). ISG15 was also increased by S1P, effects that were enhanced by MLN4760 (2-fold) and reduced by marimastat (50%). S1P increased IL-6 mRNA (1.3-fold), TNFα (6.2-fold) and IL-1β (3.3-fold). These responses were increased by by IFNs. IL-6 was increased by IFNα (1,230pg/mL) and IFNL3 (1,124pg/mL) vs control (591pg/mL). This was associated with increased phosphorylation of Stat1 (134%), Stat2 (102%), ERK1/2 (42%). Nitric oxide production and eNOS phosphorylation (Ser1177) were reduced by IFNα and (40%) and IFNL3 (40%). Reduced endothelium-relaxation maximal response (%Emax) was observed in vessels from WT-mice stimulated with IFNα (67%) and IFNL3 (71%) vs control (82%) (p&lt;0.05) but not in vessels from ISG15KO mice. Increased contraction was observed only in vessels from hypertensive mice treated with IFNα (9.1±0.5mN vs control: 7.3±0.3mN, p&lt;0.05). Conclusions: In ECs, S1P, IFNα and IFNL3 increased ISG15 and IL-6, processes that involve ADAM17 and are independent on ACE2. Inflammation induced by S1P was amplified by IFNs. IFNs induce vascular dysfunction through ISG15-dependent mechanisms, with augmented effects in hypertension.

P181 AGE-RELATED CHANGES IN THE PROTECTIVE AXIS OF THE RENIN-ANGIOTENSIN SYSTEM IN THE BRAIN OF NORMOTENSIVE AND SPONTANEOUSLY HYPERTENSIVE RATS

Background and Objective. Aging is a major risk factor for the development of hypertension, that leads to end organ damage and cognitive dysfunction. The axis of the renin-angiotensin system composed of angiotensin (Ang) (1-7) the Mas receptor (MasR) and angiotensin converting enzyme 2 (ACE2) plays a cerebroprotective role by increasing blood flow, angiogenesis and improving cognitive function among others. Evidence on the expression of this axis with age is limited. We investigated Ang-(1-7)/Mas/ACE2 axis in different areas of the brain from normotensive and spontaneously hypertensive rats (SHR). Methods. Hypothalamus (HT), brainstem (BS), hippocampus (HC) and cerebral cortex (CC) were isolated from Wistar normotensive rats and SHR of 1, 3 and 12 months. Ang-(1-7) levels were measured by radioimmunoassay and ACE2 and MasR abundance was determined by immunoblotting. Results. Ang-(1-7) levels decreased with age in all the areas from normotensive rats and in CC from SHR, while it increased from 1 to 3 months but then decreased at 12 months in BS, HC and HT from SHR. There was no difference in Ang-(1-7) levels between normotensive and SHR except at 1 month of age where Ang-(1-7) levels were lower in BS, HC and HT but the same in CC from SHR compared to normotensive rats. MasR and ACE2 expression did not change with age in all the investigated areas from normotensive rats and in CC from SHR. However, MasR and ACE2 increased with age in HC from SHR and they were higher than in normotensive rats. Conclusions. Our results showed changes in the expression of the brain Ang-(1-7)/Mas/ACE2 axis which may contribute to deleterious functions observed in the brain with age.

Activation of ACE2/Ang-(1–7)/Mas axis improves cognitive dysfunction induced by isoflurane in mice via inhibiting oxidative stress

BackgroundLong-term inhalation anesthesia is known to be associated with postoperative cognitive dysfunction. Our previous studies have confirmed that oxidative stress damage contributes to its mechanistic connection. Angiotensin-converting enzyme 2 (ACE2)/Angiotensin-(1–7)/Mas axis plays a crucial role in balancing the classic Renin-Angiotensin System (RAS) and regulating oxidative stress. This research aims to investigate the involvement of the ACE2/Angiotensin-(1–7)/Mas axis in the development of cognitive impairment induced by long-term isoflurane anesthesia. Methods3-month-old male C57BL/6 mice were randomly assigned to four groups: Control + Vehicle (C + Veh), Anesthesia + Vehicle (A + Veh), Control + Diminazene aceturate (C + DIZE), and Anesthesia + Diminazene aceturate (A + DIZE). Long-term isoflurane exposure was utilized to induce cognitive impairment. DIZE was administered intraperitoneally to mice 10 days prior to anesthesia to intervene ACE2. Cognitive function was administered using Y-maze and fear conditioning test. Flow Cytometry was used to measure the levels of ROS. Western blot was used to determine the expression levels of ACE2 and Mas, as well as the cognitive proteins such as phosphorylated N-methyl-D-aspartate receptor subtype 2B (p-NR2B) and Brain-Derived Neurotrophic Factor (BDNF). ResultsWe successfully constructed a long-term isoflurane anesthesia-mediated cognitive dysfunction model. Following long-term isoflurane anesthesia, there was a decrease in the levels of ACE2 and Mas in the hippocampus, accompanied by increased oxidative stress and significant cognitive impairment. Treatment with the ACE2 activator DIZE effectively restored the levels of ACE2 and Mas and decreased the content of ROS. Notably, DIZE treatment ameliorated cognitive dysfunction induced by long-term isoflurane exposure. ConclusionsThe findings suggest that the activation of the ACE2/Ang-(1–7)/Mas axis could reduce oxidative stress and improve cognitive impairment. ACE2/Ang-(1–7)/Mas axis may play a prophylactic role in mitigating isoflurane-induced cognitive decline and other cognitive impairments related to oxidative stress.

O98 NEW APPROACHES TARGETING THE RENIN-ANGIOTENSIN SYSTEM: BRAIN ACE2 ACTIVATION FOLLOWING BRAIN AMINOPEPTIDASE A BLOCKADE BY FIRIBASTAT IN SALT-DEPENDENT HYPERTENSION

Background and Objective: In the brain, aminopeptidase A (APA), a membrane-bound zinc metalloprotease, generates angiotensin III from angiotensin II. Brain angiotensin III exerts a tonic stimulatory effect on the control of blood pressure (BP) in hypertensive rats and increases vasopressin release. Blocking brain angiotensin III formation by the APA inhibitor prodrug RB150/firibastat normalizes arterial BP in hypertensive deoxycorticosterone acetate (DOCA)-salt rats. Ang II and Ang III have similar affinities for AT1 receptors and blocking brain AngIII formation by RB150 decreases arterial BP without inducing Ang II accumulation. Methods: We therefore hypothesized that another metabolic pathway of brain angiotensin II, such as the conversion of angiotensin II into angiotensin 1-7 (Ang 1-7) by angiotensin-converting enzyme 2 (ACE2) might be activated following brain APA inhibition. To answer this question, we use surgical animal models that could allow us to monitor awake blood pressure responses to intracerebroventricular (icv) injections and measure enzymatic activity. Results: We found that the intracerebroventricular administration of RB150/firibastat in conscious DOCA-salt rats both inhibited brain APA activity and induced an increase in brain ACE2 activity. Then, we showed that the decreases in BP and vasopressin release resulting from brain APA inhibition with RB150/firibastat were reduced if ACE2 was concomitantly inhibited by MLN4760, a potent ACE2 inhibitor, or if the Mas receptor (MasR) was blocked by A779, a MasR antagonist. Conclusions: Our findings suggest that in the brain, the increase in ACE2 activity resulting from APA inhibition by RB150/firibastat treatment, subsequently increasing Ang 1-7 and activating the MasR while blocking angiotensin III formation, contributes to the antihypertensive effect and the decrease in vasopressin release induced by RB150/firibastat. RB150/firibastat treatment constitutes an interesting therapeutic approach to improve BP control in hypertensive patients by inducing in the brain renin-angiotensin system, hyperactivity of the beneficial ACE2/Ang 1-7/MasR axis while decreasing that of the deleterious APA/Ang II/Ang III/ATI receptor axis.

Association between Angiotensin-converting enzyme (ACE) insertion/deletion (I/D) polymorphism on the susceptibility to psoriasis and oxidative stress (OS) in a cohort of pediatric psoriatic patients in Sri Lanka: A cross sectional study.

Pediatric psoriasis accounts for nearly one-third of the global psoriasis burden. Multiple lines of evidence have shown the relationship between Angiotensin-converting enzyme (ACE) Insertion (I)/deletion(D) polymorphism with psoriasis susceptibility, and oxidative stress (OS) in psoriatic patients. However, such studies, particularly on pediatric psoriasis, are scarce in the local setting. Our study investigated the prevalence of ACE I/D polymorphism and its associations with oxidative stress in pediatric psoriasis patients in Sri Lanka. Thirty patients were recruited for this study after obtaining ethical clearance. The polymerase chain reaction was used to explore the ACE I/D polymorphism. Serum Nitric Oxide (NO) levels and the Total Antioxidant Capacity (TAC) were measured using the Griess assay and the FRAP assay. Clinical details were obtained from the clinic reports. Female predominance (76.67%) in pediatric psoriasis was reported, while Plaque psoriasis (66.67%) was found to be the most prevalent form. I/D was reported as the predominant genotype (66.67%) while I/I and D/D genotypes were recorded in 23.33% and 10% of patients, respectively. Significantly higher NO levels were observed in I/D patients than in I/I patients but not among other groups. No differences in TAC among ACE genotypes were reported. This pilot study revealed female gender and I/D genotype with increased NO levels as risk factors for pediatric psoriasis in Sri Lanka. However, it is prudent to increase the sample size to further validate the results.

P137 ACE AND ACE 2 ENZYMES POLYMORPHISM IN DIFFERENT CLINICAL COVID-19 MANIFESTATIONS IN HOSPITAL-ADMITTED PATIENTS

Introduction: The affinity of SARS-CoV-2 for the Angiotensin Converting Enzyme 2 (ACE2), component of the Renin-Angiotensin System (RAS), is responsible for the COVID-19 virus internalization, and the ACE and ACE2 genes polymorphisms may contribute for the disease outcome. Objective: To correlate the I/D ACE and the G8790A ACE2 polymorphisms and their enzymatic activity to the virus susceptibility and the disease's clinical severity. Methods: 408 patients from Alfa Hospital, Recife – PE, were assessed. ACE activity was measured by fluorometry and the real time PCR technique was used to assess ACE's DD, ID, and II polymorphisms. Results: 71.9% of COVID-19 affected patients needed hospitalization, with 56.8% being male ranging from 40 to 59 years old. In the positive group, there were more patients with blood hypertension (80.6% vs 19.4%), diabetes (88.2% vs 11.8%), and obesity (87.5% vs 12.5%). ACE activity was higher in positive patients (46.5 vs 43.5 nmol/mL/min), with greater prevalence of the DD genotype, 85.6% of frequency between negatives and positives. When it comes to DD genotype, ACE activity was higher (48.5 nmol/mL/min). In patients with blood hypertension, ID genotype was more frequent than the DD one. Conclusion: The interaction of genetic and risk factors may lead to different COVID-19 symptomatology. The scientific literature states that ACE polymorphism may contribute for the development of blood hypertension, as the DD genotype being the susceptible one for developing cardiovascular complications by the higher concentration of Angiotensin II converted from Angiotensin I by ACE, increasing the hypertensive effects in relation to the anti-hypertensive ones of Angiotensin 1-7. The positive group showed more incidence of blood hypertension, diabetes and obesity, as well as higher frequency of the DD genotype, which is already established in literature to lead to blood hypertension due to increased ACE activity. From the observed in these results, it is suggested a correlation between ACE polymorphism and the factors that may aggravate COVID-19

Sivelestat protects against acute lung injury by up-regulating angiotensin-converting enzyme 2/angiotensin-(1-7)/Mas receptors.

Acute lung injury (ALI) and its most severe manifestation of acute respiratory distress syndrome (ARDS) is a disease with a clinical mortality rate of up to 40% and is one of the most dangerous and common complications of severe coronavirus disease 2019 (COVID-19). Sivelestat (SIV) is the only licensed therapeutic medicine in the world for ALI/ARDS treatment. The angiotensin-converting enzyme 2 (ACE2)/angiotensin (Ang)-(1-7)/Mas receptor axis is critical in the prevention of ALI/ARDS. This study aims to investigate whether SIV alleviates lipopolysaccharides (LPS)-induced ALI by inhibiting the down-regulation of ACE2/Ang-(1-7)/Mas receptor axis expression. In vivo, 90 male Sprague-Dawley rats were randomized into 5 groups. Then, we pretreated different groups of rats with dexamethasone (DEX) or SIV. Rats were sacrificed at three different time points (3, 6, and 12 hours) following LPS instillation. In vitro, RAW264.7 cells were divided into 11 groups. Different groups of cells were pretreated with DEX or SIV. And then added with LPS for 3, 6, and 12 hours. Next, we introduced A779, a potent Ang-(1-7) receptor antagonist, and DX600 as the ACE2 antagonist in different groups. Then the protein and messenger RNA (mRNA) expression levels of ACE2 in rat lung tissue and the expression levels of tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6) and Ang-(1-7) in the rat serum and the cell culture supernatant were measured. And the data were statistically analyzed. In vivo, the rats pretreated with SIV or DEX had significantly lower lung wet/dry (W/D) ratios and lung pathological alterations than those exposed to LPS only. Both in vivo and in vitro, we observed that SIV or DEX significantly attenuated the LPS-induced up-regulation of IL-6 and TNF-α levels, and the down-regulation of ACE2 and Ang-(1-7) levels. In vitro, the pretreatment of the RAW264.7 cells with DX600 and A779 significantly reduced and even abolished the protective effects of SIV. Therefore, it was concluded that SIV protected against LPS-induced ALI and decreased inflammatory cytokine release by up-regulating the ACE2/Ang-(1-7)/Mas receptor axis. Our results enrich the theoretical foundation for the clinical application of SIV and provide fresh ideas for the treatment of ALI/ARDS.

Abstract P212: Microinjection of the novel angiotensin, alamandine-(1-5) into insular cortex, increase blood pressure

It is well known that the renin-angiotensin system plays a critical role in cardiovascular control and hydro-electrolyte homeostasis. At least in some circumstances Alamandine (Ala) and Angiotensin-(1-7) can have selective actions such as reported in the insular córtex (IC). Hydrolysis of Angiotensin-(1-7) by angiotensin converting enzyme (ACE) can form the heptapeptide Angiotensin-(1-5) and recently our group demonstrated that hydrolysis of Ala by ACE can form Ala-(1-5). In this study we aimed to evaluate the cardiovascular effects produced by microinjection of Ala-(1-5) and Angiotensin-(1-5) into the rostral region of the posterior IC. Urethane (1.4g/kg) anesthetized rats were instrumented for measurement of mean arterial pressure (MAP), heart rate (HR) and renal sympathetic nerve activity (RSNA). Unilateral microinjection of vehicle (0,9% NaCl, 100nL, n=4), Ala (40pmol/100nl, n=7), Ala-(1-5) (400pmol/100nl, n=7) or Angiotensin-(1-5) (400pmol/100nl, n=5) were made into IC (+1.5mm rostral to the bregma). At the baseline, there was no difference between the groups (Vehicle: 85±2 mmHg and 388±5bpm, Ala: 83±9mmHg and 389±10bpm, Ala-(1–5): 91±6mmHg and 386±7bpm or Ang-(1-5): 96±9mmHg and 375±6bpm). Vehicle microinjection was performed as a control for nonspecific effects (ΔMAP:2±1mmHg, ΔHR:4±2bpm, ΔRSNA:3±1%). Ala microinjection into IC, confirmed our previous data showing a long-lasting (18±3min) increase in MAP (Δ=14±2mmHg), and this effect was associated with a significant increase in HR (Δ=32±4bpm) and in RSNA (Δ=36±6%). These responses were elicited immediately after Ala microinjection. When compared with vehicle and, very different from what was observed with Ala, microinjection of Ala-(1–5) evoked a significant increase in blood pressure without altering RSNA or HR (ΔMAP:22±2mmHg, ΔHR:-1±3bpm, ΔRSNA:1±3%). Differently from Ala evoked responses, the effects of Ala-(1–5) had a shorter duration (5.88±1.9min) without delay to beginning the effects. On other hand, microinjection of Angiotensin-(1-5) did not elicited autonomic and cardiovascular effects (ΔMAP:-1±3mmHg, ΔHR:-2±2bpm, ΔRSNA:2±3%). In conclusion, these data showed that the IC is a brain site that has unique effects of Ala (increase in MAP, HR and RSNA) and Ala-(1-5) (increase in MAP only) contrasting with the essentially absent effects of Angiotensin-(1-7) and Angiotensin-(1-5). These findings will contribute to extend our understanding of the brain renin-angiotensin system.

Expression and purification of SARS-CoV-2 receptor binding domain in Escherichia coli for diagnostic and therapeutic purposes

Background and purpose: SARS-CoV-2 causes a severe respiratory disease known as COVID-19 and is responsible for a global viral pandemic. The SARS-CoV-2 receptor binding domain (RBD) is located on the spike protein, which identifies and binds to the angiotensin-converting enzyme 2 (ACE2) receptor. The RBD is an important target for developing virus-neutralizing antibodies, vaccines, and inhibitors. Experimental approach: In this study, recombinant SARS-CoV-2 RBD was expressed in E. coli BL21 (DE3) and purified and its binding activity was determined. Purification was conducted using the Ni-NTA column. ELISA. flow cytometry assays were set to evaluate the binding ability of recombinant RBD to different anti-RBD antibodies and native ACE2 receptors on HEK293A cells, respectively. Findings/Results: The SDS-PAGE analysis revealed the corresponding band at 27 kDa in the culture after induction with 0.7 mM IPTG, while the corresponding band was not observed in the culture without IPTG induction. ELISA results showed that antibodies produced in the human sera could bind to the recombinant RBD protein and the commercial anti-RBD antibody. Also, flow cytometry analysis revealed that the recombinant RBD could bind to human ACE2 on the surface of HEK293A cells. Conclusion and implication: Our outcomes displayed that the recombinant RBD expressed in the E. coli strain has biological activity and can be used as an antigen for the development of diagnosis kits and vaccines as well as a tool for screening drugs against SASR-CoV-2.

Differential regulation of viral entry-associated genes modulated by inflammatory cytokines in the nasal epithelium.

This study aimed to investigate the impact of different types of nasal inflammation on the regulation of entry-associated genes of respiratory viruses, including severe acute respiratory syndrome coronavirus 2 (SARS CoV-2), Middle East respiratory syndrome coronavirus (MERS-CoV), human coronavirus 229E (HCoV-229E), and influenza virus, in the nasal epithelium. Subjects were classified into three groups: control, eosinophilic chronic rhinosinusitis (ECRS), and noneosinophilic CRS (NECRS) groups. Angiotensin-converting enzyme 2 (ACE2) and transmembrane protease serine subtype 2 (TMPRSS2), alanyl aminopeptidase (ANPEP), dipeptidyl peptidase 4 (DPP4), and beta-galactoside alpha-2,6-sialyltransferase 1 (ST6GAL1), and beta-galactoside alpha-2,3-sialyltransferase 4 (ST3GAL4) were selected as key entry-associated genes for SARS-CoV-2, HCoV-229E, MERS-CoV, and influenza, respectively, and were evaluated. Brushing samples obtained from each group and human nasal epithelial cells cultured using an air-liquid interface system were treated for 7 days with typical inflammatory cytokines and analyzed using real-time polymerase chain reaction. Western blot analysis and confocal microscopy were performed. The entry-associated genes showed distinct regulation patterns in response to each interleukin-4 (IL-4), interleukin-13 (IL-13), tumor necrosis factor-α (TNF-α), and interferon-γ (IFN-γ). Specifically, ACE2 significantly decreased in type 2 cytokines (IL-4 and IL-13), while TMPRSS2 significantly decreased in type 1 cytokines (TNF-α and IFN-γ). ANPEP significantly decreased in both types of cytokines. Remarkably, DPP4 significantly increased in type 2 cytokines and decreased in type 1 cytokines. Moreover, ST6GAL1 and ST3GAL4 significantly increased in type 2 cytokines and decreased in type 1 cytokines, particularly IFN-γ. These findings were supported by western blot analysis and confocal imaging results, especially for ACE2 and DPP4. The findings regarding differential regulation suggest that patients with ECRS, primarily mediated by type 2 inflammation, may have lower susceptibility to SARS-CoV-2 and HCoV-229E infections but higher susceptibility to MERS-CoV and influenza infections.

Abstract P209: The novel angiotensin Alamandine-(1-5) is increased in plasma of pediatric patients with primary nephrotic syndrome

Background and Aim: The Renin Angiotensin System (RAS) has an important role in the pathophysiology of primary nephrotic syndrome (NS). It was previously found that urinary levels of angiotensin converting enzyme 2 (ACE2) are reduced in patients with NS in comparison to health controls. The aim of this study was to measure the novel angiotensin peptide, Alamandine-(1-5), in plasma samples of patients with primary NS and to compare with sex and age-matched controls. Methods: Blood samples of pediatric patients with primary NS (n=11) and of sex and age-matched health controls (n=11) were collected in sterile tubes with 7.5% (w/v) EDTA. After plasma separation and purification by solid phase extraction, the circulating levels of Alamandine and of Alamandine-(1-5) were measured by Mass Spectrometry using multiple reaction monitoring on an ACQUITY I-Class UPLC system coupled to electrospray ionization (ESI) tandem mass spectrometry (LC-ESI-MS/MS Xevo TQ-S). Data were compared between patients and controls and associated with laboratory findings. Continuous variables were presented as mean ± standard error of the mean. Results: A total of 11 patients (7 males) with NS with mean age of 10.65±3.66 were compared to 11 controls (6 males) and with 10.86±4.35 years. In terms of disease response, 5 patients were in partial remission, 5 patients in total remission and only 1 patient was in disease relapse. All patients have normal renal function. Plasma levels of Alamandine-(1-5) were significantly higher in patients when compared to controls (28.03±7.54 vs. 10.68±3.02 pg.mL-1 in controls). Despite a mild decrease in patients, plasma levels of Alamandine did not differ between groups (19.54±6.33 vs 26.09±6.12 pg.mL-1 in controls). No correlations were found between RAS molecules and proteinuria and with the medications in use. However, Alamandine-(1-5) negatively correlated with plasma levels of albumin (r= -0.695; p=0.038). In addition, Alamandine negatively correlated with total cholesterol (r=-0.700; p = 0.036), LDL (r=-0.800; p=0.004), and HDL (r = -0.762; p = 0.038). Conclusion: The novel RAS peptide Alamandine-(1-5) is significantly increased in primary NS and inversely correlated with plasma albumin levels. These findings suggest a potential role of Alamandine-(1-5) in NS