Effect of angiotensin receptor neprilysin inhibitor on physical activity in patients with heart failure with reduced ejection fraction, monitored by implantable electronic device home monitoring.

AIMS: Angiotensin receptor neprilysin inhibitor (ARNI) therapy is a cornerstone in the treatment of heart failure with reduced ejection fraction (HFrEF), with significant improvement in mortality as well as morbidity and quality of life. However, maximal ARNI doses often result in hypotension. Recent studies with 'real world' experience suggest that lower doses of ARNI are as effective as higher doses.In order to evaluate the symptomatic effect of low-dose ARNI in HFrEF patients, we analyzed physical activity data obtained via home monitoring of patients with cardiac implantable electronic devices (CIEDs). METHODS: We retrospectively analyzed physical activity data obtained from HFrEF patients with CIED-active home monitoring during the years 2021-2022. Patients with ARNI therapy were further divided into subgroups according to the administered dose. Low-dose ARNI included doses of up to 24/26 mg sacubitril/valsartan daily. Intermediate dose and high dose included doses of 72/78-120/130 mg/day, and 144/156-194/206 mg/day, respectively. RESULTS: A total of 122 patients had home monitoring-compatible CIEDs and HFrEF during the study period. Sixty-four of these patients were treated with ARNI. Administration of low-dose ARNI resulted in a 20% increase in daily activity when compared with patients without ARNI treatment ( P  = 0.038). Change in physical activity of patients in the intermediate-dose and high-dose groups was not significant. Younger patients, patients with cardiac resynchronization therapy, and patients without diabetes mellitus were more physically active. CONCLUSION: Low-dose ARNI had a beneficial effect on physical activity in HFrEF patients. MH via CIED provided real-life objective data for patients' follow-up.

Estimating the clinical and budgetary impact of using angiotensin receptor neprilysin inhibitor as first line therapy in patients with HFrEF.

AIMS: Recent updates of international treatment guidelines for heart failure with reduced ejection fraction (HFrEF) differ regarding the use of angiotensin receptor neprilysin inhibitor (ARNI) as first-line treatment. The American Heart Association/American College of Cardiology/Heart Failure Society of America (AHA/ACC/HFSA) 2022 guidelines gives ARNI a Class IA recommendation for HFrEF patients while the European Society of Cardiology's guidelines are less clear when ARNI could be considered as first line treatment option in de novo patients. This study aimed to model the clinical and budgetary outcomes of implementing these guidelines, comparing conservative ARNI prescription patterns with less conservative in Sweden and in the United Kingdom. METHODS AND RESULTS: A health economic model was developed to compare different treatment patterns for HFrEF. Incident cohorts were included on an annual basis and followed over 10 years. The model included treatment specific all-cause mortality and hospitalization rates, as well as drug acquisition, monitoring, and hospitalization costs. Increasing the use of ARNI could lead to about 7000-12 300 life years gained and 2600-4600 hospitalizations prevented in Sweden. These health benefits come with an additional cost of 112-195 million euros. Similar results were estimated for the United Kingdom, albeit on a larger population. CONCLUSIONS: Increasing the proportion of patients receiving ARNI instead of angiotensin converting enzyme inhibitors as first-line treatment of HFrEF will lead to a considerable number of additional life years gained and prevented hospitalizations but with additional cost in terms of health care expenditure in Sweden and in the United Kingdom.

Frailty and uptake of angiotensin receptor neprilysin inhibitor for heart failure with reduced ejection fraction.

BACKGROUND: Frail older adults may be less likely to receive guideline-directed medical therapy (GDMT)-renin-angiotensin blockers, beta-blockers, and mineralocorticoid receptor antagonists-for heart failure with reduced ejection fraction (HFrEF). We aimed to examine the uptake of angiotensin receptor neprilysin inhibitor (ARNI) and GDMT in frail older adults with HFrEF. METHODS: Using 2015-2019 Medicare data, we estimated the proportion of beneficiaries with HFrEF receiving ARNI and GDMT each year by frailty status, defined by a claims-based frailty index. Logistic regression was used to identify clinical characteristics associated with ARNI initiation. Cox proportional hazards regression was used to examine the association of GDMT use in 2015 and death or heart failure hospitalization in 2016-2019. RESULTS: Among 147,506-180,386 beneficiaries with HFrEF (mean age: 77 years; 27% women; 42.6-49.1% frail) in 2015-2019, the proportion of patients receiving ARNI increased in both non-frail (0.4%-16.4%) and frail (0.3%-13.7%) patients (p for yearly-trend-by-frailty = 0.970). Among those not receiving a renin-angiotensin system blocker, patients with age ≥ 85 years (odds ratio [95% CI], 0.89 [0.80-0.99]), dementia (0.88 [0.81-0.96]), and frailty (0.87 [0.81-0.94]) were less likely to initiate ARNI. The proportion of patients receiving all 3 GDMT classes increased in non-frail patients (22.0%-27.0%) but changed minimally in frail patients (19.6%-21.8%). Regardless of frailty status, treatment with at least 1 class of GDMT was associated with lower death or heart failure hospitalization than no GDMT medications (hazard ratio [95% CI], 0.94 [0.91-0.97], 0.92 [0.89-0.94], 0.94 [0.91-0.97] for 1, 2, and 3 classes, respectively). CONCLUSIONS: Our results suggest an evidence-practice gap in the use of ARNI and GDMT in Medicare beneficiaries with HFrEF, particularly those with frailty. Efforts to narrow this gap are needed to reduce the burden of HFrEF in older adults.

Caracterización clínica y demográfica de pacientes adultos sometidos a valoración de la presión arterial con monitorización ambulatoria de la presión arterial. Registro EPEDMAPA / Clinical and demographic profile of adult patients subjected to an assessment of arterial hypertension with an ambulatory blood pressure monitoring device. EPEDMAPA Registry

Resumen Introducción: la hipertensión arterial es un problema de salud pública que aumenta la mortalidad en todos los escenarios clínicos, pero es, además, el principal factor de riesgo modificable. Es una enfermedad altamente prevalente; cerca de un cuarto de la población del mundo la padece. Pocos pacientes la conocen y pocos están tratados de manera óptima. Objetivo: evaluar las características de pacientes a quienes se les realizó una monitorización ambulatoria de la presión arterial en un Hospital Universitario, con miras a describir el perfil clínico y demográfico. Métodos: estudio descriptivo retrospectivo, llevado a cabo en pacientes sometidos a monitorización ambulatoria de la presión arterial de 24 horas durante los meses de octubre y noviembre de 2015. Resultados: se confirmó hipertensión (de reciente diagnóstico o conocida) en el 75% de los estudios realizados. Se descartó hipertensión arterial en el 31% de los pacientes previamente clasificados como hipertensos. El 61% de los pacientes que se encontraban bajo tratamiento estaban bien controlados, la mayoría de ellos con un solo medicamento, principalmente antagonistas del receptor de angiotensina II. El patrón circadiano más prevalente en esta cohorte de pacientes fue el dipper (48%) seguido por el patrón de non-dipper (29%). Conclusiones: el monitorización ambulatoria de la presión arterial permite evaluar con exactitud el estado de la presión arterial de los pacientes con sospecha de hipertensión arterial. Esto aclara si los pacientes son realmente normotensos o hipertensos y discrimina las condiciones de la bata blanca y la hipertensión enmascarada, con lo cual se evitan tratamientos innecesarios y se favorece un mejor control de la presión arterial.

Abstract Introduction: Arterial hypertension is a public health problem that increases mortality in all clinical situations. It is also the main modifiable risk factor. It is a highly prevalent condition that is suffered by around 25% of the world population. Few patients are aware of it, and few receive the optimum treatment. Objective: To evaluate the characteristics of the patients on whom ambulatory blood pressure monitoring was carried out in a University Hospital, with a view to describing the clinical and demographic profile. Methods: A descriptive retrospective study was conducted on patients subjected to 24-hour ambulatory blood pressure monitoring, during the months of October and December 2015. Results: Hypertension (recently diagnosed or known) was confirmed in 75% of the studies performed. Arterial hypertension was ruled out in 31% of the patients previously classified as hypertensive. Of the patients that were receiving treatment, 61% were well-controlled, with the majority of them with a single drug, mainly an angiotensin II receptor agonist. The dipper was most prevalent circadian pattern, with 48%, followed by the non-dipper pattern in 29%. Conclusions: Ambulatory blood pressure monitoring helps in the evaluation of the blood pressure status accurately in patients with a suspicion of arterial hypertension. This clarifies whether the patients are really normotensive or hypertensive and discriminates between the "white coat" and masked hypertension conditions. This avoids unnecessary treatments and favours a better control of the blood pressure.

Planejamento e desenvolvimento de ligantes não peptídicos com atividade agonista enviesada no receptor de angiotensina II tipo 1 empregando-se técnicas de modelagem molecular e ensaios in vitro / Drug design of non-peptidic biased agonists for angiotensin II type 1 receptor using molecular modeling techniques and in vitro tests

A insuficiência cardíaca (IC) é uma síndrome de elevada morbimortalidade, correspondendo a um grave problema de saúde pública. Uma das abordagens terapêuticas para IC consiste no uso de antagonistas do receptor de angiotensina II do tipo 1 (AT1R), conhecidos como sartanas. Estudos apontam que uma nova classe de compostos, os agonistas enviesados, é capaz de induzir a sinalização da via da ß-arrestina sem ativação da via da proteína G. Essa seletividade funcional é particularmente interessante, pois a via dependente da proteína G é responsável pelo aumento da pressão arterial, morte celular e fibrose tecidual, levando a hipertrofia cardíaca e progressão da IC. No entanto, a via da ß-arrestina está associada com renovação celular e aumento do inotropismo. Além disso, estudos in vivo sugerem que agonistas enviesados poderiam corresponder a uma terapia superior à dos antagonistas convencionais, que bloqueiam ambas as vias. Apesar do potencial terapêutico, esses compostos possuem estrutura peptídica e, por isso, tem sua administração restrita à via intravenosa. A resolução da estrutura cristalográfica do AT1R permitiu estudos de modelagem molecular mais acurados. Tendo isso em mente, nesse trabalho foram propostos agonistas enviesados de natureza não peptídica para o AT1R por meio de técnicas de modelagem molecular e validação das hipóteses levantadas por ensaios in vitro. Foram realizados estudos de dinâmica molecular com o AT1R (PDB ID: 4YAY) em uma bicamada lipídica e ensaios de ancoramento molecular da angiotensina II (AngII) e do ligante enviesado TRV027. As poses de ancoramento molecular selecionadas foram utilizadas em dinâmicas de complexo, que revelaram diferenças entre os sistemas apo (sem nenhum ligante) e holo (com o ligante no sitio de ligação). Nossos resultados sugerem que o TRV027 induz um padrão exclusivo de ligações de hidrogênio e de estrutura secundária, enquanto que a AngII afeta os resíduos do bolso hidrofóbico do sitio de ligação, principalmente a conformação do Trp2536.48. Com base nas simulações, três farmacóforos foram criados e utilizados de maneira complementar em triagens virtuais na base de dados ZINC15, resultando na seleção de cinco compostos. Um desses compostos apresentou afinidade pelo receptor AT1R e, ainda que estudos complementares de ativação de vias especificas sejam necessários para que o composto possa ser classificado como agonista enviesado, já se constitui em molécula potencialmente promissora. Além disso, esses estudos permitiram a proposição de estruturas inéditas que podem vir a ser hits no processo de desenvolvimento de agonistas enviesados para AT1R. Portanto, como continuidade desse trabalho, essas moléculas serão sintetizadas e investigadas quanto à possível interação com o receptor.

Heart Failure (HF) is a common syndrome with high morbimortality, being considered a serious public health problem. One of the therapeutic approaches for HF consists in the use of the sartan class, which are angiotensin II type 1 receptor (AT1R) antagonists. Recent studies have shown that a new class of compounds, known as biased agonists, is able to induce signaling via ß-arrestin without G-protein activation. This functional selectivity is particularly interesting since G-protein dependent signaling is responsible for cell death and cardiac tissue fibrosis, which leads to cardiac muscle hypertophy and HF progression. On the other hand, ß-arrestin signaling is associated with cellular renewal and increased inotropism. In vivo studies suggests that biased agonists could correspond to a superior therapy over conventional angiotensin II type 1 receptor antagonists, which blocks cell signaling as a whole, however their peptidic structure restricts their use to intravenous administration. Moreover, the AT1R crystal structure determination holds great promise for more accurate molecular modeling studies. With that being said, the aim of this work was to plan and develop new non-peptidic biased agonists for ATR1 employing molecular modeling techniques and in vitro tests for hypothesis validation. Molecular dynamics (MD) simulations of the refined AT1R crystal (PDB ID: 4YAY) embedded in a lipid bilayer and molecular docking studies with angiotensin II (AngII) and TRV027 (biased agonist) were conducted. Selected docking poses from both ligands underwent complex MD simulations revealing differences between apo (ligand free) and holo (ligand in the binding site) systems. Our results suggest that TRV027 induces an exclusive hydrogen bond and secondary structure pattern, while AngII affects the hydrophobic pocket conformation, mainly Trp253. Based on the simulations, three pharmacophore models were created and used in virtual screenings in the ZINC15 database, resulting in the selection of five compounds that were tested in vitro. One of the compounds displayed affinity for AT1R and is a promising molecule. Nonetheless, it needs further pathway activation characterization in order to be a classified as a biased agonist. Furthermore, these results have contributed significantly for the proposition of new structures that could be hits with biased agonist activity for AT1R. Thus, for future works, we point out the necessity for synthesis and characterization of this new compounds

Neprilysin Inhibitors: Filling a Gap in Heart Failure Management, Albeit Amidst Controversy and at a Significant Cost.

Dual angiotensin and neprilysin inhibition using the combination drug sacubitril-valsartan has ushered in a new era in the treatment of heart failure (HF). The randomized controlled PARADIGM-HF trial, which randomized 8399 patients with HF to enalapril or sacubitril-valsartan, showed a 20% reduction in mortality and HF hospitalization with the new drug. This has been heralded as a step toward filling a crucial gap in HF management by providing strong evidence that combined inhibition of the angiotensin receptor and neprilysin is superior to inhibition of the renin-angiotensin system alone in stable patients with chronic HF as it negates the deleterious effects of angiotensin while concomitantly augmenting the beneficial effects of the endogenous natriuretic peptide system. This new therapy is costly, and other confirmatory studies have been lacking for over 2 years since its approval by major regulatory authorities. As such, controversy and heated discussions have amassed, as has detailed information from a plethora of secondary analyses of this pivotal trial about the pros and cons of this promising new therapeutic strategy in HF management. The aim of this review was to provide a critical assessment of all these aspects.

Los estudios económicos en enfermedades crónicas de alta prevalencia / Economic studies in high prevalence chronic diseases

Los estudios económicos han ido ganando importancia en el mundo de las publicaciones científicas. De apenas quinientos estudios registrados en la base de datos de PubMed en 2000 con el descriptor "Costos y Análisis de Costo ("Costs and Cost Analysis"[Mesh]), se ha pasado a nueve mil publicaciones en 2014. Para nadie es un secreto que el costo de una terapia debe entrar en la fórmula, junto a su efectividad y su seguridad, al momento de tomar una decisión clínica. Muchos de los estudios se concentran en enfermedades de alto costo, como el cáncer, que registra 771 estudios publicados en el lapso 2013-2014. Pero también son de interés las enfermedades de alta prevalencia, así el costo del tratamiento del paciente individual no sea tan elevado. Es el caso de la depresión, con 602 estudios económicos en el mismo lapso.Este número de Acta Médica Colombiana presenta los resultados de la "Evaluación económica de las principales intervenciones farmacológicas como monoterapia para el tratamiento de la hipertensión arterial leve a moderada recién diagnosticada" adelantada por el equipo que lideró Rodolfo Dennis, de la Fundación Cardioinfantil de Bogotá (1). Su conclusión es que, en el paciente hipotético de 65 años que inicia terapia antihipertensiva, la monoterapia con diuréticos, al ser similar en efectividad a las terapias con inhibidores de enzima convertidora, bloqueadores del receptor de angiotensina o calcio antagonistas, resulta ser la opción más adecuada, al repre-sentar un ahorro para el sistema de salud de entre seis y veinte millones de pesos de 2011 por paciente, en valor presente, y considerando toda la vida del paciente.

Postpartum assessment of the renin angiotensin system in women with previous severe, early-onset preeclampsia.

CONTEXT: Women with a history of severe preeclampsia are at an increased risk for the development of vascular disease. OBJECTIVE: We hypothesized that abnormalities in the renin-angiotensin system (RAS) may be a predisposing factor. DESIGN AND SETTING: Physiological assessments were conducted at an academic center. PARTICIPANTS: Sixteen women with previous severe preeclampsia (PPE) were compared with nine previously pregnant controls (PPC) and 11 never-pregnant controls (NPC). INTERVENTIONS: Baseline circulating components of the RAS and expression of angiotensin (ANG) II type I (AT1) and type II (AT2) receptors in the skin were assessed along with the response to simulated orthostatic stress using incremental lower-body negative pressure (LBNP: -15, -25, and -40 mm Hg) and a graded ANG II infusion (1 and 3 ng/kg · min). MAIN OUTCOME MEASURES: Response to LBNP and ANG II was evaluated. RESULTS: RAS components were not different between previously pregnant groups, but were decreased compared with NPC subjects. In response to LBNP, there were significant increases in RAS components in all three groups, but the response to this stimulus was significantly lower and delayed in PPE subjects. Despite the blunted rise in circulating RAS mediators in PPE subjects, their blood pressure was maintained in 88% compared with only 33 and 55% in the PPC and NPC groups, respectively (P = 0.014). All three groups responded to the graded ANG II infusion with an increase in blood pressure that was significantly more pronounced in PPE subjects (P = 0.037) correlating with AT1/AT2 receptor expression. CONCLUSIONS: Alterations in the RAS in formerly preeclamptic patients may contribute to future vascular disease.

Measuring equity: an index of health care disparities.

OBJECTIVE: To create an index that would serve as a simple tool to measure the quality of hospital care by race and ethnicity. STUDY DESIGN: Following extensive review of existing disparities indices, we created a disparities quality index (DQI) designed to easily measure differences in the quality of care hospitals deliver to different populations. The DQI uses performance data already collected by virtually all hospitals. It highlights areas where there are large numbers of patients in a specific population receiving potentially lower-quality care. SETTING: Data were collected from 2 acute care hospitals that participated in a multihospital collaborative. DATA COLLECTION/EXTRACTION METHODS: We applied the DQI to 2 hospitals' quality data, specifically to their performance on the Hospital Quality Alliance measure for patients with heart failure who were receiving angiotensin-converting enzyme inhibitor or angiotensin receptor blocker. RESULTS: The DQI was simple to apply and was able to measure differences in the care of different ethnic groups. It also detected changes in disparities over time. CONCLUSIONS: The DQI can help hospitals and other providers focus on the domain of equity in their quality-improvement efforts. Further testing is required to determine its applicability for community-wide equity projects.

Health care and medication costs and use among older adults with heart failure.

BACKGROUND: Heart failure disproportionately affects older adults for whom multiple medications are prescribed to prevent exacerbations and hospitalization. To target interventions effectively, it is important to understand the association of medication acquisition with health care utilization and costs. METHODS: We used electronic medical records from an urban public health care system to identify patients aged >/=50 years who had a diagnosis of heart failure. We assessed the association between inappropriate or appropriate medication supplies and hospitalization and costs using multivariable analyses that adjusted for demographic characteristics, prior health care use, health status, and insurance status. RESULTS: Total health care costs for treating 1554 patients with heart failure from 1996 to 2000 were 36.6 million dollars (in 2000 dollars). Less than a third of patients received appropriate medication supplies (between 90% and 110% of the supplies needed) annually. Compared with patients with appropriate supplies, the odds of hospitalization were greater among those with undersupplies (odds ratio [OR] = 3.1; 95% confidence interval [CI]: 2.3 to 4.2; P <0.0001) or oversupplies (OR = 2.0; 95% CI: 1.7 to 2.4; P <0.0001). Total costs were 25% higher for patients with undersupplies (95% CI: 8% to 46%; P = 0.004) and 18% higher for those with oversupplies (95% CI: 7% to 30%; P = 0.0009) than for those with appropriate supplies. CONCLUSION: Among adults with heart failure, inappropriate medication supplies were associated with increased hospitalization and higher costs. Monitoring medication supplies from electronic medical records may be a useful component of programs aiming to improve care while managing costs.

Renin-angiotensin system gene polymorphisms: assessment of the risk of coronary heart disease.

BACKGROUND: Renin-angiotensin system genes are candidate genes in cardiovascular system diseases. Angiotensinconverting enzyme (ACE), angiotensinogen (AGT) and angiotensin II type 1 receptor (AT1R) gene polymorphisms are considered risk factors in coronary heart disease (CHD). AIM: To evaluate the involvement of the ACE, AGT and AT1R genetic variants in predisposition to CHD as well as their association with other known risk factors. METHODS: The study included 400 male subjects (200 with CHD and 200 healthy individuals). Genotypes were determined by a polymerase chain reaction (PCR). For the AGT and AT1R genes a restriction analysis of the PCR product was performed. The allele frequency and genotype distribution were compared between groups. RESULTS: The allele and genotype frequencies of the ACE gene were similar in both groups, however, a significantly higher frequency of the DD genotype was observed in the presence of hyperlipidemia (39% vs 24% in non-hyperlipidemic subjects, p<0.01). The AGT gene polymorphism was associated with the development of CHD. The T allele was significantly more frequent in patients than in the control group (55% vs 44%, p<0.05). The heterozygous MT genotype was observed in 61% of patients compared to 40% in the controls (p<0.05). The A1166C polymorphism of the AT1R gene was also associated with CHD as well as with age at the onset of disease. The frequency of the C allele was 29% compared to 21% in the control group (p<0.01) and the frequency of the CC homozygote was almost three times higher in patients. CONCLUSIONS: There is an association between molecular variants of the angiotensinogen and angiotensin II type 1 receptor and increased risk of CHD. The DD genotype of the ACE gene polymorphism and the TT genotype of the AGT gene polymorphism were significantly more frequent in patients with hyperlipidemia. The TT genotype of the AGT gene M235T polymorphism was associated with an increased risk of CHD and myocardial infarction only in smokers.

Olmesartan medoxomil: the seventh angiotensin receptor antagonist.

OBJECTIVE: To review the pharmacology, pharmacokinetics, efficacy, and adverse effects of olmesartan medoxomil, an angiotensin II receptor antagonist for the treatment of hypertension. DATA SOURCES: Information was obtained from MEDLINE searches (1996-April 2002) of English-language medical literature. Search terms included CS-866, olmesartan, olmesartan medoxomil, RNH-6270 (active metabolite of olmesartan), Benicar, angiotensin receptors, and antihypertensive agents. In addition, references from relevant articles were reviewed for additional citations. The authors independently reviewed literature identified in the searches. Studies evaluating olmesartan (i.e., abstracts, clinical trials, data on file with manufacturer) were considered for inclusion. STUDY SELECTION: All articles identified from data sources with pertinent information regarding olmesartan medoxomil were evaluated, and all information deemed relevant was included in this review. DATA SYNTHESIS: Olmesartan medoxomil is a competitively priced addition to the class of angiotensin II receptor antagonists. Monotherapy with olmesartan medoxomil in once-daily doses of 20-40 mg has produced significant reductions in systolic and diastolic blood pressure in hypertensive patients. Adverse effects have been minimal with olmesartan medoxomil, with dizziness being the only adverse effect occurring more often than with placebo in clinical trials. Additionally, animal studies indicate that olmesartan medoxomil may prove to be useful treatment for diabetic nephropathy, as well as atherosclerosis. CONCLUSIONS: Olmesartan medoxomil has a favorable safety and efficacy profile, with blood pressure-lowering effects comparable to those of other angiotensin receptor blockers (i.e., losartan, valsartan, irbesartan). At this time, formulary decisions will be driven primarily by economic issues. Theoretical benefits of olmesartan medoxomil in reducing atherogenesis and lowering angiotensin II concentrations better than the alternative agents will be determined only with more extensive research.

Structure elucidation and conformational properties of eprosartan, a non peptide angiotensin II AT1 antagonist.

A novel approach to treat hypertension is to interfere with the Renin-Angiotensin system (RAS) by blocking the binding of vasoconstrictive hormone Angiotensin II to the AT(1) receptor site. This approach led to the beneficial drug losartan (COZAAR) and other similar in structure to the antihypertensive drugs (sartans). In an effort to compare the stereoelectronic features of pharmacophoric segments of the different sartans, a research activity was initiated in our laboratory related to the conformational properties of these drugs. In a previous study, the structural features which determine the pharmacophoric segments of losartan were examined. In this study, the conformational properties of eprosartan (TEVETEN), a drug with fewer side effects, were examined. In addition, the superimposition ability of losartan and eprosartan with the peptide antagonist sarmesin was studied.

Searching for a better assessment of the individual coronary risk profile. The role of angiotensin-converting enzyme, angiotensin II type 1 receptor and angiotensinogen gene polymorphisms.

BACKGROUND: Polymorphisms within renin angiotensin system genes have been investigated as risk factors for coronary artery disease in different populations with contradicting results. The aim of this study was to investigate the genotype distribution and the allele frequencies of ACE, AT1R and AGT gene polymorphisms as coronary artery disease factors and their synergistic effects on coronary risk in an Italian population. METHODS AND RESULTDS: In this study ACE, AT1R and AGT gene polymorphisms were investigated in 205 consecutive coronary artery disease patients and in 209 controls. These polymorphisms were analysed by polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP). The ACE D and AGT 235T allele, but not AT1R C allele, frequency was statistically significant in patients. An association between coronary artery disease and ACE DD, AT1R CC and AGT TT genotype, was found by univariate analysis (OR 2.06 P=0.0007, OR 2.49 P=0.009, OR 1.87 P=0. 019, respectively). At multivariate analysis ACE DD and AT1R CC genotype (OR 1.81 P=0.011, OR 2.61 P=0.011, respectively) remained associated with coronary heart disease. Subjects carrying the ACE DD genotype and AT1R C allele showed a stronger association with myocardial infarction (OR=4.02, P<0.0001). CONCLUSION: Our report indicates the increased risk of coronary artery disease in the presence of ACE DD and AT1R CC genotypes independent of other risk factors, in Italian patients. The present study stresses the relevance of screening for genetic risk factors.

Reduced atrial angiotensin receptor type 1 mRNA content in end-stage human heart failure: assessment by a novel quantitative PCR-ELISA technique.

The number of atrial angiotensin II binding sites is reduced in end-stage human heart failure. The goals of our study were the development of a quantitative polymerase chain reaction for angiotensin II receptor type 1 mRNA to determine the angiotensin receptor type 1 (AT1) mRNA content in the atria of patients with end-stage heart failure. We established a quantitative PCR based on coamplification of AT1 wild-type and an internal standard in the same PCR, followed by liquid-phase hybridization of PCR products in microtiter plates and quantitation by ELISA. Glyceraldehyde phosphate dehydrogenase mRNA in the same samples was used to relate the AT1 mRNA content to a stably expressed reference gene. Atrial samples from 11 patients with end-stage heart failure obtained at cardiac transplantation were compared with atrial samples from 11 patients with normal cardiac function undergoing routine cardiac surgery. A PCR/ELISA system with a variance of about 6% after reverse transcription and a linear measuring range was established. In the samples from 11 patients with end-stage heart failure a 58% decrease in AT1 mRNA content was found in comparison with 11 controls (heart failure: 185,680 +/- 196,912 AT1 mRNA copies/microgram RNA, controls: 440,555 +/- 268,456, P < 0.02). When AT1 mRNA content was related to glyceraldehyde phosphate dehydrogenase mRNA, a 65% decrease was detected (AT1/glyceraldehyde phosphate dehydrogenase: heart failure: 4.84 +/- 5.18; controls: 13.74 +/- 7.77; P < 0.005). Standardization of PCR resulting in a low coefficient of variance, high reproducibility, and large sample capacity is possible using optimal internal standardization and the liquid-phase hybridization/ELISA system for detection. The optimized PCR procedure indicated downregulation of atrial AT1 in end-stage human heart failure, suggesting a reduced capacity of the atria to respond to angiotensin II stimulation in end-stage heart failure.

Angiotensin II receptor in human placental syncytiotrophoblast plasma membranes.

Previous studies have reported the presence of high-affinity angiotensin II (Ang II) binding sites in human placental tissue, but it has not been determined whether these are located in brush border (BBM) or basolateral plasma (BPM) membranes of the syncytiotrophoblast. Our findings provide no evidence for Ang II receptors in BBM, yet they reveal a single class of binding sites in BPM preparations (Kd of 4.08+/-0.61 nM and B(max) of 2368.7+/-658.2 fmol/mg protein). Pharmacological characterization also revealed that this receptor was an AT1 receptor subtype. Moreover, isoelectric focusing analysis demonstrated a predominant Ang II-receptor complex migrating to pl 7.0, and two minor receptors at pl 7.2 and 6.5. These data suggest a physiological role of the renin-angiotensin system on syncytiotrophoblast BPM in regulating placental function.

Oxytocin receptor distribution reflects social organization in monogamous and polygamous voles.

The neuropeptide oxytocin has been implicated in the mediation of several forms of affiliative behavior including parental care, grooming, and sex behavior. Here we demonstrate that species from the genus Microtus (voles) selected for differences in social affiliation show contrasting patterns of oxytocin receptor expression in brain. By in vitro receptor autoradiography with an iodinated oxytocin analogue, specific binding to brain oxytocin receptors was observed in both the monogamous prairie vole (Microtus ochrogaster) and the polygamous montane vole (Microtus montanus). In the prairie vole, oxytocin receptor density was highest in the prelimbic cortex, bed nucleus of the stria terminalis, nucleus accumbens, midline nuclei of the thalamus, and the lateral aspects of the amygdala. These brain areas showed little binding in the montane vole, in which oxytocin receptors were localized to the lateral septum, ventromedial nucleus of the hypothalamus, and cortical nucleus of the amygdala. Similar differences in brain oxytocin receptor distribution were observed in two additional species, the monogamous pine vole (Microtus pinetorum) and the polygamous meadow vole (Microtus pennsylvanicus). Receptor distributions for two other neurotransmitter systems implicated in the mediation of social behavior, benzodiazepines, and mu opioids did not show comparable species differences. Furthermore, in the montane vole, which shows little affiliative behavior except during the postpartum period, brain oxytocin receptor distribution changed within 24 hr of parturition, concurrent with the onset of maternal behavior. We suggest that variable expression of the oxytocin receptor in brain may be an important mechanism in evolution of species-typical differences in social bonding and affiliative behavior.

Oxytocin--a neuropeptide for affiliation: evidence from behavioral, receptor autoradiographic, and comparative studies.

Oxytocin (OT) is a nine amino acid peptide synthesized in hypothalamic cells which project either to the neurohypophysis or to sites within the central nervous system. Although neurohypophyseal OT release has long been associated with uterine contraction and milk ejection, the function of intracerebral OT remains unclear. On the basis of behavioral, cellular, and comparative studies, this review suggests that brain OT influences the formation of social bonds. The first part of this review examines evidence linking central OT to several forms of affiliation. Central administration of OT induces maternal and reproductive behaviors in rats primed with gonadal steroids. OT antagonists and hypothalamic lesions block the initiation of maternal and reproductive behaviors but have no effects on these behaviors once established. Our new studies in rat pups demonstrate that central OT selectively decreases the separation response, an effect which mimics social contact. These studies of parental, reproductive, and attachment behaviors suggest that exogenous OT has "prosocial" effects and that endogenous OT may be essential for initiating social interaction. In a second series of experiments, we investigated the cellular mechanisms for OT's effects on social behavior by means of autoradiographic receptor binding. In the rat forebrain, OT receptors are expressed in several limbic regions believed to be involved in the integration of sensory processing. The regulation of these receptors is surprisingly resistant to either ablation of OT cells or repeated central administration of OT. However, receptors in two regions, the bed nucleus of the stria terminalis (BNST) and the ventromedial nucleus of the hypothalamus (VMN), appear selectively induced by exogenous or endogenous increases in gonadal steroids. At parturition, binding to OT receptors increases 84% in the BNST, and at estrus, binding increases 35% in the VMN. These results demonstrate that physiologic changes in gonadal steroids can alter receptor expression in anatomically discrete target fields and thereby direct responsiveness to endogenous neuropeptide release. A model for OT's effects on social behavior is proposed, which relies on the heterologous regulation of the brain OT receptor. A third series of experiments tested the hypothesis that brain OT influences affiliation by comparing prairie and montane voles, two closely related species with dichotomous systems of social organization. Although no differences appear in the presynaptic expression of the neuropeptide, OT receptors are distributed in complementary patterns in the two species. In the highly affiliative prairie vole, receptors are most evident in the BNST and one of its primary afferents, the lateral amygdala, highlighting a circuit previously implicated in maternal behavior.(ABSTRACT TRUNCATED AT 400 WORDS)