New aspects on angiotensin-converting enzyme: from gene to disease

Classical and nonclassical effects of angiotensin-converting enzyme: How increased ACE enhances myeloid immune function

As part of the classical renin-angiotensin system, the peptidase angiotensin-converting enzyme (ACE) makes angiotensin II which has myriad effects on systemic cardiovascular function, inflammation, and cellular proliferation. Less well known is that macrophages and neutrophils make ACE in response to immune activation which has marked effects on myeloid cell function independent of angiotensin II. Here, we discuss both classical (angiotensin) and nonclassical functions of ACE and highlight mice called ACE 10/10 in which genetic manipulation increases ACE expression by macrophages and makes these mice much more resistant to models of tumors, infection, atherosclerosis, and Alzheimer's disease. In another model called NeuACE mice, neutrophils make increased ACE and these mice are much more resistant to infection. In contrast, ACE inhibitors reduce neutrophil killing of bacteria in mice and humans. Increased expression of ACE induces a marked increase in macrophage oxidative metabolism, particularly mitochondrial oxidation of lipids, secondary to increased peroxisome proliferator-activated receptor α expression, and results in increased myeloid cell ATP. ACE present in sperm has a similar metabolic effect, and the lack of ACE activity in these cells reduces both sperm motility and fertilization capacity. These nonclassical effects of ACE are not due to the actions of angiotensin II but to an unknown molecule, probably a peptide, that triggers a profound change in myeloid cell metabolism and function. Purifying and characterizing this peptide could offer a new treatment for several diseases and prove potentially lucrative.

Review Article on Molecular Mechanism of Regulation of Hypertension by Macro-elements (Na, K, Ca and Mg), Micro-elements/Trace Metals (Zn and Cu) and Toxic Elements (Pb and As)

Hypertension (HT) is a medical condition arising due to increase in blood pressure (BP) prevalent worldwide. The balanced dietary intakes of macro-elements and micro-elements including Na, K, Ca, Mg, Zn, and Cu have been described to maintain BP in humans by regulating the osmolarity of blood, cells/tissues, prevention of generation of oxidative and nitrosative stress (OANS), and endothelial damage through their functioning as important components of renin-angiotensin-aldosterone system (RAAS), antioxidant enzyme defense system, and maintenance of blood vascular-endothelial and vascular smooth muscle cell (VSMC) functions. However, inadequate/excess dietary intakes of Na/K, Ca/Mg, and Zn/Cu along with higher Pb and As exposures recognized to induce HT through common mechanisms including the followings: endothelial dysfunctions due to impairment of vasodilatation, increased vasoconstriction and arterial stiffness, blood clotting, inflammation, modification of sympathetic activity and higher catecholamine release, increased peripheral vascular resistance, and cardiac output; increased OANS due to reduced and elevated activities of extracellular superoxide dismutase and NAD(P)H oxidase, less nitric oxide bioavailability, decrease in cGMP and guanylate cyclase activity, increase in intracellular Ca2+ ions in VSMCs, and higher pro-inflammatory cytokines; higher parathyroid and calcitriol hormones; activation/suppression of RAAS resulting imbalance in blood Na+, K+, and water regulated by renin, angiotensin II, and aldosterone through affecting natriuresis/kaliuresis/diuresis; elevation in serum cholesterol and LDL cholesterol, decrease in HDL cholesterol due to defect in lipoprotein metabolism. The present study recommends the need to review simple dietary mineral intervention studies/supplementation trials before keeping their individual dietary excess intakes/exposures in consideration because their interactions lead to elevation and fall of their concentrations in body affecting onset of HT.

Detection of Various Traditional Chinese Medicinal Metabolites as Angiotensin-Converting Enzyme Inhibitors: Molecular Docking, Activity Testing, and Surface Plasmon Resonance Approaches

Angiotensin-converting enzyme 1 (ACE1) is a peptide involved in fluid and blood pressure management. It regulates blood pressure by converting angiotensin I to angiotensin II, which has vasoconstrictive effects. Previous studies have shown that certain compounds of natural origin can inhibit the activity of angiotensin-converting enzymes and exert blood pressure-regulating effects. Surface Plasmon Resonance (SPR) biosensor technology is the industry standard method for observing biomolecule interactions. In our study, we used molecular simulation methods to investigate the docking energies of various herbal metabolites with ACE1 proteins, tested the real-time binding affinities between various herbal metabolites and sACE1 by SPR, and analyzed the relationship between real-time binding affinity and docking energy. In addition, to further explore the connection between inhibitor activity and real-time binding affinity, several herbal metabolites' in vitro inhibitory activities were tested using an ACE1 activity test kit. The molecular docking simulation technique's results and the real-time affinity tested by the SPR technique were found to be negatively correlated, and the virtual docking technique still has some drawbacks as a tool for forecasting proteins' affinities to the metabolites of Chinese herbal metabolites. There may be a positive correlation between the enzyme inhibitory activity and the real-time affinity detected by the SPR technique, and the results from the SPR technique may provide convincing evidence to prove the interaction between herbal metabolites and ACE1 target proteins.

The effects of enhancing angiotensin converting enzyme in myelomonocytes on ameliorating Alzheimer's-related disease and preserving cognition

This review examines the role of angiotensin-converting enzyme (ACE) in the context of Alzheimer's disease (AD) and its potential therapeutic value. ACE is known to degrade the neurotoxic 42-residue long alloform of amyloid β-protein (Aβ42), a peptide strongly associated with AD. Previous studies in mice, demonstrated that targeted overexpression of ACE in CD115+ myelomonocytic cells (ACE10 models) improved their immune responses to effectively reduce viral and bacterial infection, tumor growth, and atherosclerotic plaque. We further demonstrated that introducing ACE10 myelomonocytes (microglia and peripheral monocytes) into the double transgenic APPSWE/PS1ΔE9 murine model of AD (AD+ mice), diminished neuropathology and enhanced the cognitive functions. These beneficial effects were dependent on ACE catalytic activity and vanished when ACE was pharmacologically blocked. Moreover, we revealed that the therapeutic effects in AD+ mice can be achieved by enhancing ACE expression in bone marrow (BM)-derived CD115+ monocytes alone, without targeting central nervous system (CNS) resident microglia. Following blood enrichment with CD115+ ACE10-monocytes versus wild-type (WT) monocytes, AD+ mice had reduced cerebral vascular and parenchymal Aβ burden, limited microgliosis and astrogliosis, as well as improved synaptic and cognitive preservation. CD115+ ACE10-versus WT-monocyte-derived macrophages (Mo/MΦ) were recruited in higher numbers to the brains of AD+ mice, homing to Aβ plaque lesions and exhibiting a highly Aβ-phagocytic and anti-inflammatory phenotype (reduced TNFα/iNOS and increased MMP-9/IGF-1). Moreover, BM-derived ACE10-Mo/MΦ cultures had enhanced capability to phagocytose Aβ42 fibrils, prion-rod-like, and soluble oligomeric forms that was associated with elongated cell morphology and expression of surface scavenger receptors (i.e., CD36, Scara-1). This review explores the emerging evidence behind the role of ACE in AD, the neuroprotective properties of monocytes overexpressing ACE and the therapeutic potential for exploiting this natural mechanism for ameliorating AD pathogenesis.

The role of angiotensin I converting enzyme insertion/deletion polymorphism in the severity and outcomes of COVID-19 patients

The pandemic of coronavirus disease in 2019 has led to a global crisis. COVID-19 shows distinct clinical manifestations of the severity of symptoms. Numerous patients with no associated risk factors demonstrate acute respiratory distress syndrome (ARDS). The role of genetic factors in determining the severity and outcome of the disease remains unresolved. The purpose of this study was to see if a correlation exists between Angiotensin I Converting Enzyme (ACE) insertion/deletion (I/D) polymorphism and the severity of COVID-19 patients’ symptoms. 120 COVID-19 patients admitted to Masih Daneshvari Hospital in Tehran with their consent to participate entered the study. Based on the World Health Organization classification, patients were divided into moderate and severe groups, which were primarily affected by O2 saturation levels. The effects of the patients’ ACE insertion/deletion polymorphism, background disease, Angiotensin receptor blocker (ARB) drug consumption, and demographic parameters on the severity risk were calculated statistically. The ACE D allele was associated with an increased risk of disease severity (OR = 6.766, p = 0.012), but had no effect on mortality.

Heavy metals controlling cardiovascular diseases risk factors in myocardial infarction patients in critically environmentally heavy metal-polluted steel industrial town Mandi-Gobindgarh (India)

Heavy metals (HMs) have a very significant clinical role in the pathogenesis, progression and management of cardiovascular diseases (CVDs). The prevalence of CVDs was reported to be higher in critically environmentally HM-polluted (EHMP) steel industrial town Mandi-Gobindgarh (India) for the last more than a decade. To ascertain the role of HMs in the onset of CVDs, the present study was chosen to investigate HMs content in myocardial infarction (MI) patients from EHMP steel industrial town Mandi-Gobindgarh. Total of 110 MI patients along with number- and age-matched healthy volunteers were recruited in the present investigation. The CVDs risk factors estimated in MI patients were overweight (higher body mass index), hypertension (higher systolic and diastolic blood pressures), dyslipidaemia (higher serum cholesterol, triglycerides and lower HDL cholesterol), inflammation (higher-serum C reactive protein and aldosterone) and elevated oxidative stress (higher urinary 8-hydroxydeoxyguanosine). An imbalance of serum electrolyte concentrations including Na (hypernatremia), Ca (hypercalcaemia) and K (hypokalaemia) was also observed in MI patients in which CVDs risk factors were found to correlate positively with serum Na and Ca and negatively with serum K, respectively. Hair HM analysis was used as a bio-indicator for monitoring body HM status from past environmental HM exposure in which CVDs risk factors were observed to correlate positively with higher hair concentrations of Zn, Fe, Mo, Pb, As, Ca and Na and negatively with lower hair concentrations of Cu, Mg, Mn and K in MI patients, respectively. Thus, higher hair concentrations of Zn and Pb indicate their higher environmental exposure and possible cause of higher CVDs risk factors in MI patients from Mandi-Gobindgarh.

The non-cardiovascular actions of ACE

Angiotensin converting enzyme (ACE) is well known for its role producing the vasoconstrictor angiotensin II and ACE inhibitors are commonly used for treating hypertension and cardiovascular disease. However, ACE has many different substrates besides angiotensin I and plays a role in many different physiologic processes. Here, we discuss the role of ACE in the immune response. Several studies in mice indicate that increased expression of ACE by macrophages or neutrophils enhances the ability of these cells to respond to immune challenges such as infection, neoplasm, Alzheimer's disease, and atherosclerosis. Increased expression of ACE induces increased oxidative metabolism with an increase in cell content of ATP. In contrast, ACE inhibitors have the opposite effect, and in both humans and mice, administration of ACE inhibitors reduces the ability of neutrophils to kill bacteria. Understanding how ACE affects the immune response may provide a means to increase immunity in a variety of chronic conditions now not treated through immune manipulation.

The Race for ACE: Targeting Angiotensin-Converting Enzymes (ACE) in SARS-CoV-2 Infection

The SARS-CoV-2 virus is spreading around the world, and its clinical manifestation COVID-19 is challenging medical, economic, and social systems. With more and more scientific and social media reports on the COVID-19 pandemic appearing, differences in geographical presentations and clinical management occur. Since ACE2 (angiotensin-converting enzyme 2) is the gatekeeper receptor for the SARS-CoV-2 virus in the upper bronchial system, we here focus on the central role of the renin-angiotensin aldosterone system (RAAS) in the SARS-CoV-2 virus infection, the role of pharmacological RAAS inhibitors, and specific genetic aspects, i.e., single nucleotide polymorphisms (SNP) for the clinical outcome of COVID-19. We aimed to bring together clinical, epidemiological, molecular, and pathophysiological and pharmacological data/observations on cardiovascular aspects in the actual SARS-CoV-2 virus pandemic. In detail, we will report controversies about the Yin-Yan between ACE2 and ACE1 and potential implications for the treatment of hypertension, coronary artery disease, and heart failure. Here, we summarize the encouraging and dynamic global effort of multiple biomedical disciplines resulted in astonishing fight against COVID-19 targeting the renin-angiotensin-aldosterone system, yet the race for ACE just begun.

Genetic variants affecting chemical mediated skin immunotoxicity

The skin is an immune-competent organ and this function may be impaired by exposure to chemicals, which may ultimately result in immune-mediated dermal disorders. Interindividual variability to chemical-induced skin immune reactions is associated with intrinsic individual characteristics and their genomes. In the last 30-40 years, several genes influencing susceptibility to skin immune reactions were identified. The aim of this review is to provide information regarding common genetic variations affecting skin immunotoxicity. The polymorphisms selected for this review are related to xenobiotic-metabolizing enzymes (CYPA1 and CYPB1 genes), antioxidant defense (GSTM1, GSTT1, and GSTP1 genes), aryl hydrocarbon receptor signaling pathway (AHR and ARNT genes), skin barrier function transepidermal water loss (FLG, CASP14, and SPINK5 genes), inflammation (TNF, IL10, IL6, IL18, IL31, and TSLP genes), major histocompatibility complex (MHC) and neuroendocrine system peptides (CALCA, TRPV1, ACE genes). These genes present variants associated with skin immune responses and diseases, as well as variants associated with protecting skin immune homeostasis following chemical exposure. The molecular and association studies focusing on these genetic variants may elucidate their functional consequences and contribution in the susceptibility to skin immunotoxicity. Providing information on how genetic variations affect the skin immune system may reduce uncertainties in estimating chemical hazards/risks for human health in the future.

Angiotensin converting enzyme (ACE)

BACKGROUND

Angiotensin converting enzyme (ACE) was isolated as a 'hypertensinconverting enzyme'. There have been considerable advances in understanding the metabolic role of ACE in the body. This review attempts to highlight the role of ACE enzyme in the physiological and pathological processes occurring in the organs in which it is localized.

METHODS

The literature was searched from the websites of the National Library of Medicine (http://www.ncbi.nlm.nih.gov/) and Pub Med Central, the U.S. National Library of Medicine's digital archive of life sciences journal literature.

RESULTS

The involvement of ACE in regulation of blood pressure forms its central action but it has a role to play in a variety of physiological processes occurring in the organs in which it is localized like the lungs, macrophages, brain, pancreas, liver etc. It has also been implicated in the pathogenesis of a number of diseases including COVID-19.

CONCLUSIONS

More studies need to be carried out in order to validate the use of ACE levels in the diagnosis and monitoring of the diseases associated, and facilitate the use of ACE inhibitors and Angiotensin Receptor Blockers in the management of the same, so this wonder molecule can be utilized to its full potential.

An ACE inhibitor reduces bactericidal activity of human neutrophils in vitro and impairs mouse neutrophil activity in vivo

Angiotensin-converting enzyme inhibitors (ACEIs) are used by millions of patients to treat hypertension, diabetic kidney disease, and heart failure. However, these patients are often at increased risk of infection. To evaluate the impact of ACEIs on immune responses to infection, we compared the effect of an ACEI versus an angiotensin receptor blocker (ARB) on neutrophil antibacterial activity. ACEI exposure reduced the ability of murine neutrophils to kill methicillin-resistant Staphylococcus aureus (MRSA), Pseudomonas aeruginosa, and Klebsiella pneumoniae in vitro. In vivo, ACEI-treated mice infected with MRSA had increased bacteremia and tissue bacteria counts compared to mice treated with an ARB or with no drug. Similarly, ACEIs, but not ARBs, increased the incidence of MRSA-induced infective endocarditis in mice with aortic valve injury. Neutrophils from ACE knockout (KO) mice or mice treated with an ACEI produced less leukotriene B4 (LTB4) upon stimulation with MRSA or lipopolysaccharide, whereas neutrophils overexpressing ACE produced more LTB4 compared to wild-type neutrophils. As a result of reduced LTB4 production, ACE KO neutrophils showed decreased survival signaling and increased apoptosis. In contrast, neutrophils overexpressing ACE had an enhanced survival phenotype. Last, in a cohort of human volunteers receiving the ACEI ramipril for 1 week, ACEI administration reduced neutrophil superoxide and reactive oxygen species production and neutrophils isolated from volunteers during ramipril treatment had reduced bactericidal activity. Together, these data demonstrate that ACEI treatment, but not ARB treatment, can reduce the bacterial killing ability of neutrophils.

Immunohistochemistry in the Postmortem Diagnosis of Sepsis: A Systematic Review

It is not uncommon for the forensic pathologist to question whether a deceased person had experienced sepsis that could have either been the cause of or contributed to the person's death. Often, the missing typical pathologic factors or lack of clinical and circumstantial information on the death render the autopsy of a sepsis-related death a difficult task for the forensic pathologist. Several authors emphasize on how an immunohistochemical analysis could help in diagnosing death related to sepsis. The research we carried out analyzes the main scientific studies in the literature, primarily the tracing of 21 immunohistochemical antigens evaluated to help diagnose death related to sepsis. The purpose of this review was to analyze and summarize the markers studied until now and to consider the limitations of immunohistochemistry that currently exist with regard to this particular field of forensic pathology. Immunohistochemistry provided interesting and promising results, but further studies are needed in order for them to be confirmed, so that they may be applied in standard forensic practice.

Coronavirus: Pure Infectious Disease or Genetic Predisposition

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which causes novel coronavirus disease (COVID-19), is the seventh pathogenic coronavirus recently discovered in December 2019 in Wuhan, China. To date, our knowledge about its effect on the human host remains limited. It is well known that host genetic factors account for the individual differences in the susceptibility to infectious diseases. The genetic susceptibility factors to COVID-19 and its severity are associated with several unanswered questions. However, the experience gained from an earlier strain of coronavirus, SARS-CoV-1, which shows 78% genetic similarity to SARS-CoV-2 and uses the same receptor to bind to host cells, could provide some clues. It, therefore, seems possible to assemble new evidence in order to solve a potential genetic predisposition puzzle for COVID-19. In this chapter, the puzzle pieces, including virus entry receptors, immune response, and inflammation-related genes, as well as the probable genetic predisposition models to COVID-19, are discussed.

Accelerated Repurposing and Drug Development of Pulmonary Hypertension Therapies for COVID-19 Treatment Using an AI-Integrated Biosimulation Platform

The COVID-19 pandemic has reached over 100 million worldwide. Due to the multi-targeted nature of the virus, it is clear that drugs providing anti-COVID-19 effects need to be developed at an accelerated rate, and a combinatorial approach may stand to be more successful than a single drug therapy. Among several targets and pathways that are under investigation, the renin-angiotensin system (RAS) and specifically angiotensin-converting enzyme (ACE), and Ca²⁺-mediated SARS-CoV-2 cellular entry and replication are noteworthy. A combination of ACE inhibitors and calcium channel blockers (CCBs), a critical line of therapy for pulmonary hypertension, has shown therapeutic relevance in COVID-19 when investigated independently. To that end, we conducted in silico modeling using BIOiSIM, an AI-integrated mechanistic modeling platform by utilizing known preclinical in vitro and in vivo datasets to accurately simulate systemic therapy disposition and site-of-action penetration of the CCBs and ACEi compounds to tissues implicated in COVID-19 pathogenesis.

Serum INHB Levels and ACE Gene I/D Polymorphism with Increased Risk for Unexplained Infertility

ACE has a significant role in the angiogenesis of ovarian endothelium and the resumption of meiosis and folicular growth. However, there is no any study concerning ACE polymorphism and UI. The main aim of this study is that both identify ACE polymorphism and measure the serum ACE, AMH and INHB levels in UI patients and controls in Turkish population. 47 UI patients and 41 controls were involved in this study. To determine the ACE polymorphisms, DNA isolation and PCR were performed. Then, serum ACE, AMH and INHB levels were measured spectrophotometrically. Patients with UI had significantly higher serum INHB levels compared with controls (p < 0.05). Serum ACE levels were decreased, compared to controls, however the decrease were not significant. Serum AMH levels did not significantly differ from controls. When the relationship were analyzed between ACE I/D polymorphism and infertility risk, and ID genotype were chosen as reference, it was found to be 2.33 times more risk of UI that the women have DD genotype (DD vs. ID: odds ratio = 2.33, 95% confidence interval (0,88-6,19); p = 0,086). This finding indicates that DD genotype may be high risk for UI. Further studies are warranted to confirm this finding, especially with a larger population.

Impact of I/D polymorphism of angiotensin-converting enzyme 1 (ACE1) gene on the severity of COVID-19 patients

Severe acute respiratory syndrome corona virus-2 (SARS-CoV-2) has first emerged from China in December 2019 and causes coronavirus induced disease 19 (COVID-19). Since then researchers worldwide have been struggling to detect the possible pathogenesis of this disease. COVID-19 showed a wide range of clinical behavior from asymptomatic to severe acute respiratory disease syndrome. However, the etiology of susceptibility to severe lung injury is not yet fully understood. Angiotensin-converting enzyme1 (ACE1) convert angiotensin I into Angiotensin II that was further metabolized by ACE 2 (ACE2). The binding ACE2 receptor to SARS-CoV-2 facilitate its enter into the host cell. The interaction and imbalance between ACE1 and ACE2 play a crucial role in the pathogenesis of lung injury. Thus, the aim of this study was to investigate the association of ACE1 I/D polymorphism with severity of Covid-19.

The study included RT-PCR confirmed 269 cases of Covid-19. All cases were genotyped for ACE1 I/D polymorphism using polymerase chain reaction and followed by statistical analysis (SPSS, version 15.0).

We found that ACE1 DD genotype, frequency of D allele, older age (≥46 years), unmarried status, and presence of diabetes and hypertension were significantly higher in severe COVID-19 patient. ACE1 ID genotype was significantly independently associated with high socio-economic COVID-19 patients (OR: 2.48, 95% CI: 1.331–4.609).

These data suggest that the ACE1 genotype may impact the incidence and clinical outcome of COVID-19 and serve as a predictive marker for COVID-19 risk and severity.

The role of renin-angiotensin system activated phagocytes in the SARS-CoV-2 coronavirus infection

OBJECTIVE

Management of the pandemic caused by the novel coronavirus SARS-CoV-2 challenges both scientists and physicians to rapidly develop, and urgently assess, effective diagnostic tests and therapeutic interventions. The initial presentation of the disease in symptomatic patients is invariably respiratory, with dry cough being the main symptom, but an increasing number of reports reveal multiple-organ involvement. The aim of this review is to summarize the potential role of the renin-angiotensin system activated phagocytes in the pathogenesis of COVID-19 disease.

METHODS

Data for this review were identified by searches of PubMed and references from relevant articles using the search terms "SARS," "COVID-19," "renin-angiotensin-system," "phagocyte," "reactive free radical," "antioxidant," "ARDS," "thrombosis," "myocardial," "ischaemia," "reperfusion," "microvascular," and "ACE2." Abstracts and reports from meetings were not included in this work. Only articles published in English between 1976 and 2020 were reviewed.

RESULTS

The cellular target of SARS viruses is the angiotensin-converting enzyme 2, a critical regulating protein in the renin-angiotensin system. The elimination of this enzyme by the viral spike protein results in excessive activation of phagocytes, migration into the tissues via the high endothelial venules, and an oxidative burst. In the case of an overstimulated host immune response, not only devastating respiratory symptoms but even systemic or multiorgan involvement may be observed.

CONCLUSIONS

Early-stage medical interventions may assist in returning the exaggerated immune response to a normal range; however, some therapeutic delay might result in excessive tissue damages, occasionally mimicking a systemic disease with a detrimental outcome.

Angiotensin-Converting Enzyme Gene Polymorphism and Severe Lung Injury in Patients with Coronavirus Disease 2019

Coronavirus disease 2019 has markedly varied clinical presentations, with most patients being asymptomatic or having mild symptoms. However, severe acute respiratory disease, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is common and associated with mortality in patients who require hospitalization. The etiology of susceptibility to severe lung injury remains unclear. Angiotensin II, converted by angiotensin-converting enzyme (ACE) from angiotensin I and metabolized by ACE 2 (ACE2), plays a pivotal role in the pathogenesis of lung injury. ACE2 is identified as an essential receptor for SARS-CoV-2 to enter the cell. The binding of ACE2 and SARS-CoV-2 leads to the exhaustion and down-regulation of ACE2. The interaction and imbalance between ACE and ACE2 result in an unopposed angiotensin II. Considering that the ACE insertion (I)/deletion (D) gene polymorphism contributes to the ACE level variability in general population, in which mean ACE level in DD carriers is approximately twice that in II carriers, we propose a hypothesis of genetic predisposition to severe lung injury in patients with coronavirus disease 2019. It is plausible that the ACE inhibitors and ACE receptor blockers may have the potential to prevent and to treat the acute lung injury after SARS-CoV-2 infection, especially for those with the ACE genotype associated with high ACE level.

Angiotensin-Converting Enzyme Gene Polymorphism and Severe Lung Injury in Patients with Coronavirus Disease 2019

Coronavirus disease 2019 has markedly varied clinical presentations, with most patients being asymptomatic or having mild symptoms. However, severe acute respiratory disease, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is common and associated with mortality in patients who require hospitalization. The etiology of susceptibility to severe lung injury remains unclear. Angiotensin II, converted by angiotensin-converting enzyme (ACE) from angiotensin I and metabolized by ACE 2 (ACE2), plays a pivotal role in the pathogenesis of lung injury. ACE2 is identified as an essential receptor for SARS-CoV-2 to enter the cell. The binding of ACE2 and SARS-CoV-2 leads to the exhaustion and down-regulation of ACE2. The interaction and imbalance between ACE and ACE2 result in an unopposed angiotensin II. Considering that the ACE insertion (I)/deletion (D) gene polymorphism contributes to the ACE level variability in general population, in which mean ACE level in DD carriers is approximately twice that in II carriers, we propose a hypothesis of genetic predisposition to severe lung injury in patients with coronavirus disease 2019. It is plausible that the ACE inhibitors and ACE receptor blockers may have the potential to prevent and to treat the acute lung injury after SARS-CoV-2 infection, especially for those with the ACE genotype associated with high ACE level.

Role of angiotensin-converting enzyme in myeloid cell immune responses

Angiotensin-converting enzyme (ACE), a dicarboxypeptidase, plays a major role in the regulation of blood pressure by cleaving angiotensin I into angiotensin II (Ang II), a potent vasoconstrictor. Because of its wide substrate specificity and tissue distribution, ACE affects many diverse biological processes. In inflammatory diseases, including granuloma, atherosclerosis, chronic kidney disease and bacterial infection, ACE expression gets upregulated in immune cells, especially in myeloid cells. With increasing evidences connecting ACE functions to the pathogenesis of these acquired diseases, it is suggested that ACE plays a vital role in immune functions. Recent studies with mouse models of bacterial infection and tumor suggest that ACE plays an important role in the immune responses of myeloid cells. Inhibition of ACE suppresses neutrophil immune response to bacterial infection. In contrast, ACE overexpression in myeloid cells strongly induced bacterial and tumor resistance in mice. A detailed biochemical understanding of how ACE activates myeloid cells and which ACE peptide(s) (substrate or product) mediate these effects could lead to the development of novel therapies for boosting immunity against a variety of stimuli, including bacterial infection and tumor.

Towards Neuro-CoViD-19

CoViD-19 is the current pandemic caused by the Severe Acute Respiratory Syndrome Corona Virus-2 (SARS-CoV-2). Infection by SARS-CoV-2 occurs via the binding of its S protein to the angiotensin-converting enzyme-2 receptor (ACE2-R). S binding to ACE2-R leads to a drop in ACE2, a homolog of angiotensin converting enzyme (ACE). In the central nervous system (CNS), ACE mediates neuroinflammation, neurodegeneration and neurotoxicity responsible for several CNS disorders. ACE2 counteracts the damaging effects of ACE on CNS neurons. SARS-CoV-2 can directly access the CNS via the circulation or via cranial nerve I and the olfactory bulb. Inactivation of ACE2 following binding of SARS-CoV-2 S protein to ACE2-R in situ might blunt ACE2-moderating effects upon ACE CNS neurotoxicity and neurodegeneration. Here, we propose a neurobiological mechanism directly involving SARS-CoV-2 binding to ACE2-R in the etiology of putative Neuro-CoViD-19.

ACE overexpression in myeloid cells increases oxidative metabolism and cellular ATP

Angiotensin-converting enzyme (ACE) affects blood pressure. In addition, ACE overexpression in myeloid cells increases their immune function. Using MS and chemical analysis, we identified marked changes of intermediate metabolites in ACE-overexpressing macrophages and neutrophils, with increased cellular ATP (1.7-3.0-fold) and Krebs cycle intermediates, including citrate, isocitrate, succinate, and malate (1.4-3.9-fold). Increased ATP is due to ACE C-domain catalytic activity; it is reversed by an ACE inhibitor but not by an angiotensin II AT1 receptor antagonist. In contrast, macrophages from ACE knockout (null) mice averaged only 28% of the ATP levels found in WT mice. ACE overexpression does not change cell or mitochondrial size or number. However, expression levels of the electron transport chain proteins NDUFB8 (complex I), ATP5A, and ATP5β (complex V) are significantly increased in macrophages and neutrophils, and COX1 and COX2 (complex IV) are increased in macrophages overexpressing ACE. Macrophages overexpressing ACE have increased mitochondrial membrane potential (24% higher), ATP production rates (29% higher), and maximal respiratory rates (37% higher) compared with WT cells. Increased cellular ATP underpins increased myeloid cell superoxide production and phagocytosis associated with increased ACE expression. Myeloid cells overexpressing ACE indicate the existence of a novel pathway in which myeloid cell function can be enhanced, with a key feature being increased cellular ATP.

Overexpression of ACE in Myeloid Cells Increases Immune Effectiveness and Leads to a New Way of Considering Inflammation in Acute and Chronic Diseases

PURPOSE OF REVIEW

To review recent studies exploring how myeloid cell overexpression of angiotensin-converting enzyme (ACE) affects the immune response and to formulate an approach for considering the effectiveness of inflammation in cardiovascular disease RECENT FINDINGS: While it is widely appreciated that the renin-angiotensin system affects aspects of inflammation through the action of angiotensin II, new studies reveal a previously unknown role of ACE in myeloid cell biology. This was apparent from analysis of two mouse lines genetically modified to overexpress ACE in monocytes/macrophages or neutrophils. Cells overexpressing ACE demonstrated an increased immune response. For example, mice with increased macrophage ACE expression have increased resistance to melanoma, methicillin-resistant Staphylococcus aureus, a mouse model of Alzheimer's disease, and ApoE-knockout-induced atherosclerosis. These data indicate the profound effect of increasing myeloid cell function. Further, they suggest that an appropriate way to evaluate inflammation in both acute and chronic diseases is to ask whether the inflammatory infiltrate is sufficient to eliminate the immune challenge. The expression of ACE by myeloid cells induces a heightened immune response by these cells. The overexpression of ACE is associated with immune function beyond that possible by wild type (WT) myeloid cells. A heightened immune response effectively resolves disease in a variety of acute and chronic models of disease including models of Alzheimer's disease and atherosclerosis.

Overexpression of myeloid angiotensin-converting enzyme (ACE) reduces atherosclerosis

BACKGROUND

Macrophages are ubiquitous in all stages of atherosclerosis, exerting tremendous impact on lesion progression and plaque stability. Because macrophages in atherosclerotic plaques express angiotensin-converting enzyme (ACE), current dogma posits that local myeloid-mediated effects worsen the disease. In contrast, we previously reported that myeloid ACE overexpression augments macrophage resistance to various immune challenges, including tumors, bacterial infection and Alzheimer's plaque deposition. Here, we sought to assess the impact of myeloid ACE on atherosclerosis.

METHODS

A mouse model in which ACE is overexpressed in myelomonocytic lineage cells, called ACE10, was generated and sequentially crossed with ApoE-deficient mice to create ACE^10/10ApoE^-/- (ACE10/ApoE). Control mice were ACE^WT/WTApoE^-/- (WT/ApoE). Atherosclerosis was induced using an atherogenic diet alone, or in combination with unilateral nephrectomy plus deoxycorticosterone acetate (DOCA) salt for eight weeks.

RESULTS

With an atherogenic diet alone or in combination with DOCA, the ACE10/ApoE mice showed significantly less atherosclerotic plaques compared to their WT/ApoE counterparts (p < 0.01). When recipient ApoE^-/- mice were reconstituted with ACE^10/10 bone marrow, these mice showed significantly reduced lesion areas compared to recipients reconstituted with wild type bone marrow. Furthermore, transfer of ACE-deficient bone marrow had no impact on lesion area.

CONCLUSION

Our data indicate that while myeloid ACE may not be required for atherosclerosis, enhanced ACE expression paradoxically reduced disease progression.

The Angiotensin Converting Enzyme I/D Polymorphism in Turkish Athletes and Sedentary Controls

The angiotensin converting enzyme (ACE) gene is located on human chromosome 17 expressing three genotypes within the intron 16 of the related gene structure. These genotypes are classified as I and D alleles which are termed as insertion and deletion, respectively. This study was carried out to identify possible relationships between the insertion/ deletion (I/D) polymorphisms and athletic performance in Turkish athletes. To be able to determine these relationships, eighty healthy athletes and eighty healthy sedentary controls were genotyped for the ACE I/D polymorphism at gene level. According to the results obtained, we found significant difference on ACE I/D polymorphism in between athletes and healthy controls (x2 = 7.32, df = 2, P = 0.026). This result supports the association in ACE genotype in Turkish athletes, suggesting that this might be a genetic factor influencing the physical performance.

Association of DD genotype of angiotensin-converting enzyme gene (I/D) polymorphism with hypertension among a North Indian population

Hypertension, a major risk factor for cardiovascular diseases, is among the leading causes of morbidity and mortality worldwide. Genetic predisposition to the risk of developing hypertension due to angiotensin-converting enzyme (ACE) gene insertion(I)/deletion(D) polymorphism (through altered serum ACE activity) is well documented among various populations. The present study investigated the possible association between ACE (DD) genotype and hypertension using a nested case-control study design including 451 individuals (of either sex in the age group 30-65 years) from a rural North Indian population practicing agriculture and lacto-vegetarianism. Blood Pressure was classified using JNC-7 criterion. Age- and sex-matched individuals were selected from normotensive (N-122), pre-hypertensive (N-123), hypertensive not on medication (N-122), and hypertensive on medication (N-84) categories. Amplification of DNA and genotyping of PCR product was done using standard protocols. From the analysis, comparatively higher frequency of individuals with DD genotype in the hypertensive category was observed, indicating a possible relation between DD genotype and hypertension. The odds ratio analysis revealed 2.225 (1.13-4.37)-fold significant increased risk for hypertension among cases, validating the vulnerability of individuals with DD genotype towards hypertension. Thus, the present study highlights the increased risk for developing hypertension due to ACE DD genotype in the studied population.

Association between dementia and vascular disease-associated polymorphisms in a Tunisian population

PURPOSE

Dementia is a multifactorial idiopathic pathology caused by clinical, eDementia is a multifactorial idiopathic pathology caused by clinical, environmental and genetic factors. Hence, its etiology is still unknown. We aimed to evaluate the association between five genetic risk factors for vascular diseases and dementia individually and when gathered in haplotypes.

MATERIALS AND METHOD

We enrolled 200 dementia patients and 300 controls. All subjects were genotyped for vascular diseaseassociated polymorphisms in the genes coding for Apolipoprotein-E (ApoE), angiotensin converting enzyme (ACE) and Paraoxonase-1 (PON1).

RESULTS

The association between dementia risk and all the studied polymorphisms except of PON1-Q192R was found to be significant. Carrying the ApoE e4 allele seems to increase dementia risk by 4.32 fold (p = 0.001). The risk associated with ACE I and PON1-L55M T alleles were lower (2.58 and 2.11 fold, p < 0.001 and p = 0.015, respectively). When combined in haplotypes, these polymorphisms showed a cumulative and synergetic effect. GTICC haplotype appears to be associated with 9-fold dementia risk (p < 0.001), whereas AADTT seems to reduce dementia risk by 80% (p = 0.003).

CONCLUSION

Our results suggest that, ApoE ε4, ACE I and PON1-L55M T alleles are associated with dementia risk whether these polymorphisms were studied separately or gathered in haplotypes. Still, the contribution of each gene to the pathophysiological development of dementia must be more investigated.

A Fluorometric Method of Measuring Carboxypeptidase Activities for Angiotensin II and Apelin-13

Degradation of the biologically potent octapeptide angiotensin Ang II-(1-8) is mediated by the activities of several peptidases. The conversion of Ang II to the septapeptide Ang-(1-7) is of particular interest as the latter also confers organ protection. The conversion is catalyzed by angiotensin-converting enzyme 2 and other enzymes that selectively cleave the peptide bond between the proline and the phenylalanine at the carboxyl terminus of Ang II. The contribution of various enzyme activities that collectively lead to the formation of Ang-(1-7) from Ang II, in both normal conditions and in disease states, remains only partially understood. This is largely due to the lack of a reliable and sensitive method to detect these converting activities in complex samples, such as blood and tissues. Here, we report a fluorometric method to measure carboxypeptidase activities that cleave the proline-phenylalanine dipeptide bond in Ang II. This method is also suitable for measuring the conversion of apelin-13. The assay detects the release of phenylalanine amino acid in a reaction with the yeast enzyme of phenylalanine ammonia lyase (PAL). When used in cell and mouse organs, the assay can robustly measure endogenous Ang II and apelin-13-converting activities involved in the renin-angiotensin and the apelinergic systems, respectively.

Assessment of the environmental and genetic factors influencing prevalence of metabolic syndrome in Saudi Arabia

Metabolic syndrome (MS) is a combination of factors that increases the risk of cardiovascular atherosclerotic diseases including diabetes, obesity, dyslipidemia, and high blood pressure. Cardiovascular diseases are one of the leading causes of death in the adult Saudi population where the increase in cardiovascular-related mortality is augmented by the rise in the prevalence of MS. Metabolic syndrome is a multi-factorial disorder influenced by interactions between genetic and environmental components. This review aims to provide a comprehensive assessment of studied environmental and genetic factors explaining the prevalence of MS in the Kingdom of Saudi Arabia. Additionally, this review aims to illustrate factors related to the population genetics of Saudi Arabia, which might explain a proportion of the prevalence of MS.

Pathological interactions between the endothelin-1 and the angiotensin- converting enzyme among Tunisian coronary patients

Background

The correct understanding of the biochemical and metabolic interactions between coronary risk factors contribute to the exploration of cardiovascular pathophysiology and improves therapeutic care.

The aim of this study was to explore the endothelin-1 (ET-1) concentration and the angiotensin converting enzyme (ACE) activity among Tunisian patients with coronary heart disease, and to investigate the metabolic relationships between these two markers,… and to assess the possible relationship between them and the different risk factors.

In this present study, ET-1 concentration was determined by an analytical method (High Performance Chromatography, coupled by Mass Spectrometry), ACE activity was measured by a kinetic method for patients and healthy controls. These subjects (157 patients and 142 controls) beneficed also by a biochemical exploration (lipid, apolipoproteins and glucose profiles) to quantify cardiovascular risk.

Results

A statistically significant increase of the ET-1 concentration was found among patients compared to healthy controls (15.2 ± 5.3 nM vs 7.1 ± 2.7 nM, p < 0,00001). For the ACE activity, in spite the treatment of the majority of patients (97%) with ACE inhibitors, this activity was statistically elevated in patients compared to healthy subjects (86.7 ± 25.4 IU/L vs 42.8 ± 12.1 IU/L, p < 0.00001).

Furthermore, a statistically positive correlation was identified between these two cardiac markers (r = 0.68 p < 0.00001).

Conclusion

The study of the metabolic relationship between the ET-1 and ACE among coronary patients reveals other therapeutics targets.

Effect of 24-Week Treatment with Telmisartan on Myocardial Structure and Function: Relationship to Insertion/Deletion Polymorphism of the Angiotensin-Converting Enzyme Gene

The aim of the present study was to assess the effect of treatment with the angiotensin II receptor blocker telmisartan for 24 weeks on myocardial structure and function in patients with essential hypertension, and the relationship between this effect and the structural polymorphism of the angiotensin-converting enzyme (ACE) gene. Thirty-five patients with essential hypertension and left ventricular hypertrophy (LVH) without other associated morbidity were included in an open-label, non-comparative study. The patients were treated with telmisartan 40-80 mg once daily. In the final analysis, there were 29 patients who received the full course of treatment and were evaluated echocardiographically before and after treatment by the same blinded investigator, and myocardial structure and function were analysed. The myocardial mass of the left ventricle was determined in M-mode. Assessment of diastolic function of transmitral blood flow was performed using pulsed Doppler echocardiography. All patients were genotyped for insertion/deletion (I/D) polymorphism of the ACE gene. Telmisartan produced a significant reduction in left ventricular mass index from 140.4 ± 48.6 to 128.7 ± 40.6 g/m2 that was accompanied by an improvement in characteristics of diastolic function. The decrease in LVH was more significant in the ID genotype group than in the II and DD groups. Thus, prolonged treatment with telmisartan is accompanied by an improvement in myocardial structure, expressed as a reduction in left ventricular mass and function that is more marked in patients with ID genotype of the ACE gene.

Genetic Association Between CD143 rs4340 Polymorphism and Pneumonia risk: A Meta Analysis

rs4340 polymorphism at intron 16 of the angiotensin-converting enzyme (CD143) gene was reported to repress cough reflex by reducing bradykinin and substance P levels, thus increasing the likelihood to develop pneumonia. There have been different reports regarding the correlation of CD143 rs4340 genotypes with pneumonia risk, which prompted us to perform a meta-analysis to determine the elusive association.We combined multiple keywords to identify the studies addressing the association between CD143 rs4340 genotypes and pneumonia risk covered in the EMBASE, Google Scholar, PubMed, and CNKI databases. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated to assess the risk of pneumonia. The fixed-effects model (FEM) was used.A total of 10 studies were analyzed in this quantitative analysis. We found a strong association between rs4340 single nucleotide polymorphism (SNP) and pneumonia risk using the recessive model (FEM: OR 1.33, 95% CI 1.13-1.57). A significantly increased risk was also indicated under the recessive model in Asian populations (FEM: OR 1.57, 95% CI 1.19-2.07), community-acquired pneumonia (CAP) (FEM: OR 1.31, 95% CI 1.08-1.60), and nosocomial pneumonia (NP) (FEM: OR 1.52, 95% CI 1.06-2.19).Our meta-analysis demonstrates that CD143 rs4340 polymorphism may represent a risk factor for pneumonia.

Increased risk of pneumonia associated with angiotensin-converting enzyme (CD143) rs4340 polymorphism

The study aims to investigate the genetic association between rs4340 polymorphism at intron 16 of the angiotensin-converting enzyme (CD143) gene and pneumonia predisposition. Electronic database of PubMed, Embase, and CNKI (China National Knowledge Infrastructure) was searched for the studies addressing the association between CD143 rs4340 genotypes and pneumonia risk. The odds ratio (OR) with its 95 % confidence interval (CI) was employed to estimate the association. In total, ten case-control studies, including 1239 pneumonia cases and 2400 healthy controls, met the inclusion criteria. Our results showed a significant association between rs4340 SNP and pneumonia risk using the recessive model (OR 1.43, 95 % CI 1.20-1.70). A significantly increased risk was also indicated under the recessive model in Asian populations (OR 1.63, 95 % CI 1.16-2.30), Caucasian populations (OR 1.34, 95 % CI 1.09-1.65), community-acquired pneumonia (OR 1.42, 95 % CI 1.16-1.75) rather than nosocomial pneumonia (OR 1.47, 95 % CI 0.97-2.23). However, further studies with gene-gene and gene-environmental interactions should be considered to confirm this association.

Evaluation of ACE gene I/D polymorphism in Iranian elite athletes

Background:

Angiotensin converting enzyme (ACE) is an important gene, which is associated with the successful physical activity. The ACE gene has a major polymorphism (I/D) in intron 16 that determines its plasma and tissue levels. In this study, we aimed to determine whether there is an association between this polymorphism and sports performance in our studied population including elite athletes of different sports disciplines. We investigated allele frequency and genotype distribution of the ACE gene in 156 Iranian elite athletes compared to 163 healthy individuals. We also investigated this allele frequency between elite athletes in three functional groups of endurance, power, and mixed sports performances.

Materials and Methods:

DNA was extracted from peripheral blood, and polymerase chain reaction (PCR) method was performed on intron 16 of the ACE gene. The ACE genotype was determined for each subject. Statistical analysis was performed by SPSS 15, and results were analyzed by Chi-Square test.

Results:

There was a significant difference in genotype distribution and allele frequency of the ACE gene in athletes and control group (P = 0.05, P = 0.03, respectively). There was also a significant difference in allele frequency of the ACE gene in 3 groups of athletes with different sports disciplines (P = 0.045). Proportion of the ACE gene D allele was greater in elite endurance athletes (37 high-distance cyclists) than two other groups.

Conclusions:

Findings of the present study demonstrated that there is an association between the ACE gene I/D polymorphism and sports performance in Iranian elite athletes.

Mesenchymal Stem Cells Overexpressing Angiotensin-Converting Enzyme 2 Rescue Lipopolysaccharide-Induced Lung Injury

Bone marrow-derived mesenchymal stem cells (MSCs), which have beneficial effects in acute lung injury (ALI), can serve as a vehicle for gene therapy. Angiotensin-converting enzyme 2 (ACE2), a counterregulatory enzyme of ACE that degrades angiotensin (Ang) II into Ang 1-7, has a protective role against ALI. Because ACE2 expression is severely reduced in the injured lung, a therapy targeted to improve ACE2 expression in lung might attenuate ALI. We hypothesized that MSCs overexpressing ACE2 would have further benefits in lipopolysaccharide (LPS)-induced ALI mice, when compared with MSCs alone. MSCs were transduced with ACE2 gene (MSC-ACE2) by a lentiviral vector and then infused into wild-type (WT) and ACE2 knockout (ACE2(-/y)) mice following an LPS-induced intratracheal lung injury. The results demonstrated that the lung injury of ALI mice was alleviated at 24 and 72 h after MSC-ACE2 transplantation. MSC-ACE2 improved the lung histopathology and had additional anti-inflammatory effects when compared with MSCs alone in both WT and ACE2(-/y) ALI mice. MSC-ACE2 administration also reduced pulmonary vascular permeability, improved endothelial barrier integrity, and normalized lung eNOS expression relative to the MSC group. The beneficial effects of MSC-ACE2 could be attributed to its recruitment into the injured lung and enhanced local expression of ACE2 protein without changing the serum ACE2 levels after MSC-ACE2 transplantation. The biological activity of the increased ACE2 protein decreased the Ang II amount and increased the Ang 1-7 level in the lung when compared with the ALI and MSC-only groups, thereby inhibiting the detrimental effects of accumulating Ang II. Therefore, compared to MSCs alone, the administration of MSCs overexpressing ACE2 resulted in a further improvement in the inflammatory response and pulmonary endothelial function of LPS-induced ALI mice. These additional benefits could be due to the degradation of Ang II that accompanies the targeted overexpression of ACE2 in the lung.

Angiotensin-converting enzyme I/D polymorphism is associated with pneumonia risk: a meta-analysis

BACKGROUND

Previous studies examined the association between angiotensin-converting enzyme (ACE) I/D polymorphism and pneumonia, but their results were inconsistent. Thus, a meta-analysis was performed to clarify the effect of ACE I/D polymorphism on pneumonia risk and pneumonia-related mortality.

METHODS

The PubMed, Embase, and Chinese National Knowledge Infrastructure (CNKI) databases were searched for relevant studies published up to 27 April 2013. Data were extracted and pooled odds ratios (ORs) with 95% confidence intervals (CIs) were calculated.

RESULTS

Pooled analysis of 12 case-control studies (1431 cases and 3600 controls) showed that there was a significant association between ACE I/D polymorphism and pneumonia risk in a recessive genetic model (OR = 1.53, 95% CI 1.30-1.80, p < 0.00001). No significant association between ACE I/D polymorphism and mortality was observed (OR = 2.68, 95% CI 0.80-8.90, p = 0.11).

CONCLUSIONS

Our meta-analysis confirmed that ACE I/D polymorphism was associated with pneumonia risk. However, ACE I/D polymorphism was not associated with pneumonia mortality.

The functional role of MnSOD as a biomarker of human diseases and therapeutic potential of a new isoform of a human recombinant MnSOD

Reactive oxygen species (ROS) are generated as a consequence of metabolic reactions in the mitochondria of eukaryotic cells. This work describes the role of the manganese superoxide dismutase (MnSOD) as a biomarker of different human diseases and proposes a new therapeutic application for the prevention of cancer and its treatment. The paper also describes how a new form of human MnSOD was discovered, its initial application, and its clinical potentials. The MnSOD isolated from a human liposarcoma cell line (LSA) was able to kill cancer cells expressing estrogen receptors, but it did not have cytotoxic effects on normal cells. Together with its oncotoxic activity, the recombinant MnSOD (rMnSOD) exerts a radioprotective effect on normal cells irradiated with X-rays. The rMnSOD is characterized by the presence of a leader peptide, which allows the protein to enter cells: this unique property can be used in the radiodiagnosis of cancer or chemotherapy, conjugating radioactive substances or chemotherapic drugs to the leader peptide of the MnSOD. Compared to traditional chemotherapic agents, the drugs conjugated with the leader peptide of MnSOD can selectively reach and enter cancer cells, thus reducing the side effects of traditional treatments.

Lack of association of genetic polymorphisms of angiotensin converting enzyme 1 and angiotensin II type 1 receptor with breast cancer risk in Iranian population

We aimed to investigate the association of insertion/deletion (I/D) and A1166C polymorphisms of angiotensin I converting enzyme 1 and angiotensin II type 1 receptor genes, respectively and their combination on breast cancer risk in an Iranian population. A case-control study (70 cases, 70 controls) was performed on an Iranian population. The I/D and A1166C polymorphisms were analyzed by polymerase chain reaction (PCR) and restriction fragment length polymorphism PCR, respectively. The results revealed no significant difference between cases and controls in I/D (p = 0.14) and A1166C (p = 0.94) polymorphisms after adjustment for breast cancer known risk factors. In combined genotype analysis, considering DD and AA genotypes as low-risk genotypes, women with one and two high-risk genotypes (one high-risk genotype: adjusted odds ratio (OR), 1.24; two high-risk genotypes: adjusted OR, 1.97) were at higher risk for breast cancer. Also, the highest risk for breast cancer was seen in a subgroup of postmenopausal women carriers of two high-risk genotypes (adjusted OR, 2.41). In conclusion, I/D and A1166C polymorphisms are not significantly associated with breast cancer risk in the Iranian population; however, the combination of these two polymorphisms seems to have a synergic effect on the risk of breast cancer particularly in postmenopausal women, which may deserve consideration in large-scale case-control studies.

Multi-species comparative analysis of the equine ACE gene identifies a highly conserved potential transcription factor binding site in intron 16

Angiotensin converting enzyme (ACE) is essential for control of blood pressure. The human ACE gene contains an intronic Alu indel (I/D) polymorphism that has been associated with variation in serum enzyme levels, although the functional mechanism has not been identified. The polymorphism has also been associated with cardiovascular disease, type II diabetes, renal disease and elite athleticism. We have characterized the ACE gene in horses of breeds selected for differing physical abilities. The equine gene has a similar structure to that of all known mammalian ACE genes. Nine common single nucleotide polymorphisms (SNPs) discovered in pooled DNA were found to be inherited in nine haplotypes. Three of these SNPs were located in intron 16, homologous to that containing the Alu polymorphism in the human. A highly conserved 18 bp sequence, also within that intron, was identified as being a potential binding site for the transcription factors Oct-1, HFH-1 and HNF-3β, and lies within a larger area of higher than normal homology. This putative regulatory element may contribute to regulation of the documented inter-individual variation in human circulating enzyme levels, for which a functional mechanism is yet to be defined. Two equine SNPs occurred within the conserved area in intron 16, although neither of them disrupted the putative binding site. We propose a possible regulatory mechanism of the ACE gene in mammalian species which was previously unknown. This advance will allow further analysis leading to a better understanding of the mechanisms underpinning the associations seen between the human Alu polymorphism and enzyme levels, cardiovascular disease states and elite athleticism.

No evidence for the expression of renin-angiotensin-aldosterone system in otosclerotic stapes footplates

INTRODUCTION

Recent studies have reported genetic associations between with single nucleotide polymorphism (SNP) of the several genes of the renin-angiotensin-aldosterone (RAA) system in otosclerosis without the confirmation of RAA system expression in human stapes footplates. There are conflicting results. These results are conflicting because RAA system expression has been attributed exclusively to neural, vascular, and renal tissues, exclusively.

MATERIALS AND METHODS

Ankylotic stapes footplates (n = 20), cortical bone fragments (n = 10), and human kidney tissue specimens (n = 10) were processed to hematoxylin-eosin (HE) staining and RAA system-specific immunofluorescent assay (IFA), respectively.

RESULTS

Histologic diagnosis of otosclerosis was established in all ankylotic stapes footplates. Histologically active- (n = 13) and inactive (n = 7) foci of otosclerosis were consequently characterized by negative immunoreactions for renin, angiotensin converting enzyme (ACE), angiotensin-II (AT-II), and angiotensin-II receptor (AT-IIR), consequently. In cortical bones, a considerable RAA system expression was observed confirmed in the perivascular bone marrow progenitor cells. Kidney specimens, applied as positive controls, showed intense RAA system-specific immunoreactions.

CONCLUSION

Concerning current observations, the 4 studied members of RAA system that did not display active expression were not expressed at protein level in otosclerotic stapes footplates. This phenomenon was independent from the histologic activity of otosclerosis. Between these conditions, the etiologic role of RAA system is questionable in the pathogenesis of otosclerosis.

Oxidative stress in apoptosis and cancer: an update

The oxygen paradox tells us that oxygen is both necessary for aerobic life and toxic to all life forms. Reactive oxygen species (ROS) touch every biological and medical discipline, especially those involving proliferative status, supporting the idea that active oxygen may be increased in tumor cells. In fact, metabolism of oxygen and the resulting toxic byproducts can cause cancer and death. Efforts to counteract the damage caused by ROS are gaining acceptance as a basis for novel therapeutic approaches, and the field of prevention of cancer is experiencing an upsurge of interest in medically useful antioxidants. Apoptosis is an important means of regulating cell numbers in the developing cell system, but it is so important that it must be controlled. Normal cell death in homeostasis of multicellular organisms is mediated through tightly regulated apoptotic pathways that involve oxidative stress regulation. Defective signaling through these pathways can contribute to both unbalance in apoptosis and development of cancer. Finally, in this review, we discuss new knowledge about recent tools that provide powerful antioxidant strategies, and designing methods to deliver to target cells, in the prevention and treatment of cancer.

ACE gene insertion/deletion polymorphism seminal associations in infertile men

PURPOSE

We assessed seminal associations of the ACE gene insertion/deletion polymorphism in infertile men.

MATERIALS AND METHODS

A total of 405 men were investigated, divided into healthy fertile men, and those with asthenozoospermia, asthenoteratozoospermia and oligoasthenoteratozoospermia, respectively. They underwent semen analysis, and assessment of sperm acrosin activity, hypo-osmotic swelling, seminal 8-iso-prostaglandin-F(2α), total antioxidant capacity, α-glucosidase and ACE gene polymorphisms.

RESULT

The ACE insertion/insertion genotype was noted in 182 men, including 76.5% of healthy fertile men, and 47.4%, 39.8% and 17.6% of those with asthenozoospermia, asthenoteratozoospermia and oligoasthenoteratozoospermia, respectively. The ACE insertion/deletion genotype was noted in 133 men, including 13.7% of healthy fertile men, and 42.3%, 27.5% and 47.2% of those with asthenozoospermia, asthenoteratozoospermia and oligoasthenoteratozoospermia, respectively. The ACE deletion/deletion genotype was identified in 90 men, including 9.8% of healthy fertile men, 10.3%, 32.70% and 35.2% of those with asthenozoospermia, asthenoteratozoospermia and oligoasthenoteratozoospermia, respectively. Men with the ACE deletion/deletion and insertion/deletion genotypes showed a significant decrease in sperm count, motility, linear velocity and normal forms, acrosin activity index, hypo-osmotic swelling test and seminal α-glucosidase, and significantly increased seminal 8-iso-prostaglandin-F(2α) than those with the ACE insertion/insertion genotype.

CONCLUSIONS

ACE gene deletion polymorphism is associated with abnormal seminal variables, such that carriers of the ACE deletion/deletion genotype have higher seminal oxidative stress.

Acute respiratory distress syndrome leads to reduced ratio of ACE/ACE2 activities and is prevented by angiotensin-(1-7) or an angiotensin II receptor antagonist

Acute respiratory distress syndrome (ARDS) is a devastating clinical syndrome. Angiotensin-converting enzyme (ACE) and its effector peptide angiotensin (Ang) II have been implicated in the pathogenesis of ARDS. A counter-regulatory enzyme of ACE, ie ACE2 that degrades Ang II to Ang-(1-7), offers a promising novel treatment modality for this syndrome. As the involvement of ACE and ACE2 in ARDS is still unclear, this study investigated the role of these two enzymes in an animal model of ARDS. ARDS was induced in rats by intratracheal administration of LPS followed by mechanical ventilation. During ventilation, animals were treated with saline (placebo), losartan (Ang II receptor antagonist), or with a protease-resistant, cyclic form of Ang-(1-7) [cAng-(1-7)]. In bronchoalveolar lavage fluid (BALF) of ventilated LPS-exposed animals, ACE activity was enhanced, whereas ACE2 activity was reduced. This was matched by enhanced BALF levels of Ang II and reduced levels of Ang-(1-7). Therapeutic intervention with cAng-(1-7) attenuated the inflammatory mediator response, markedly decreased lung injury scores, and improved lung function, as evidenced by increased oxygenation. These data indicate that ARDS develops, in part, due to reduced pulmonary levels of Ang-(1-7) and that repletion of this peptide halts the development of ARDS.

Role of angiotensin-converting enzyme gene polymorphism in persistent pulmonary hypertension of the newborn

AIM

To evaluate the association of angiotensin-converting enzyme (ACE) gene polymorphism with risk/severity of persistent pulmonary hypertension of the newborn (PPHN) among at risk infants.

METHODS

Infants ≥ 34 weeks with respiratory distress at birth were recruited. PPHN was diagnosed clinically and by cardiac echocardiogram. Control group consisted of infants with respiratory distress who did not develop PPHN. ACE genotyping (DD, II, DI genotypes) and serum ACE levels were determined.

RESULTS

A total of 120 infants were included (PPHN = 44; control = 76). Frequency of ACE DD genotype was not different between the two groups of infants (25% versus 33%). Among PPHN infants, severity of illness did not differ between genotypes. Mean (SD) serum ACE levels [15 (9) versus 24 (13) versus 29 (14) U/L] were positively associated with the number of D alleles and inversely associated with infants' gestational age (GA) and level of cardiovascular support.

CONCLUSION

Angiotensin-converting enzyme gene polymorphism did not impact the risk or severity of PPHN among infants ≥ 34 weeks GA.