atrial-natriuretic-factor and Stroke

This meta-analysis was performed to evaluate the correlations between atrial natriuretic peptide (ANP) genetic polymorphism and its serum ANP levels with the risk of ischemic stroke.. The PubMed, CISCOM, CINAHL, Web of Science, Google Scholar, EBSCO, Cochrane Library, and CBM databases were searched for relevant articles published before October 1st, 2013 without language restrictions. Meta-analysis was conducted using the STATA 12.0 software. Crude odds ratios (ORs) or standardized mean difference (SMD) with their 95% confidence interval (95% CI) were calculated. Twelve case-control studies that met all inclusion criteria were included in this meta-analysis. A total of 1285 patients with ischemic stroke and 1088 healthy control subjects were involved in this meta-analysis. Three common single-nucleotide polymorphisms (1837 G/A, 2238 T/C, and 664 G/A) in the ANP gene were assessed.. Our meta-analysis results revealed that ANP 2238 T/C polymorphism might increase the risk of ischemic stroke (C allele vs. T allele: OR=2.26, 95% CI: 1.59-3.23, p<0.001; TC+CC vs. TT: OR=2.26, 95% CI: 1.34-3.81, p=0.002; respectively). However, we found no correlations of ANP 1837 G/A and 664 G/A polymorphisms with ischemic stroke risk (all p>0.05). Furthermore, ischemic stroke patients had higher levels of serum ANP than those of healthy control subjects (SMD=3.12, 95% CI: 1.16-5.07, p=0.002). Our study revealed no publication bias in this meta-analysis (all p>0.05).. Our findings indicate that ANP genetic polymorphism and serum ANP levels may contribute to the development of ischemic stroke. Thus, the ANP genetic polymorphism and serum ANP levels could be potential biomarkers for early detection of ischemic stroke.

Topics: Atrial Natriuretic Factor; Biomarkers; Brain Ischemia; Case-Control Studies; Genetic Predisposition to Disease; Humans; Polymorphism, Genetic; Stroke

The Losartan Intervention For Endpoint reduction in hypertension (LIFE) study is the first, and, so far, the only endpoint trial in patients with hypertension and left ventricular hypertrophy (LVH) to show a divergent therapeutic outcome of one treatment modality over another with equivalent blood pressure control. The purpose of this article is to review post hoc sub-analyses of LIFE study data and other clinical studies that offer some insight into possible treatment-related differences contributing to the superior stroke outcome of losartan versus atenolol beyond blood pressure reduction.. Relevant randomized clinical trials and review articles were identified through a MEDLINE search of English-language articles published between 1990 and 2006 using the search terms losartan, atenolol, LIFE, hypertension, and LVH. Articles describing major clinical studies, new data, or mechanisms pertinent to the LIFE study were selected for review.. Differences in blood pressure or in the distribution of add-on medications were not evident between study groups in the LIFE study. Thus, the observed outcomes benefits favoring losartan may involve other possible mechanisms, including differential effects of losartan and atenolol on LVH regression, left atrial diameter, atrial fibrillation, brain natriuretic peptide, vascular structure, thrombus formation/platelet aggregation, serum uric acid, albuminuria, new-onset diabetes, and lipid metabolism. Alternative explanations for the LIFE study findings have also been put forward, including the choice of atenolol as an appropriate active comparator and differential effects between treatment groups on central pulse pressure. Additional clinical trials are needed to determine if the beneficial effects of losartan seen in LIFE are shared by other inhibitors of the renin-angiotensin system.. Sub-analyses of the LIFE study data suggest that losartan's stroke benefit may arise from a mosaic of mechanisms rather than a single action. Further studies are expected to continue to delineate the mechanisms of differential responses to treatments in LIFE.

Topics: Adrenergic beta-Antagonists; Angiotensin II Type 1 Receptor Blockers; Antihypertensive Agents; Atenolol; Atrial Fibrillation; Atrial Natriuretic Factor; Biomarkers; Blood Pressure; Cardiovascular Agents; Cohort Studies; Drug Utilization; Endothelium, Vascular; Follow-Up Studies; Heart Atria; Humans; Hypertension; Hypertrophy, Left Ventricular; Losartan; Models, Biological; Myocardial Infarction; Natriuretic Peptide, Brain; Peptide Fragments; Platelet Aggregation; Platelet Aggregation Inhibitors; Protein Precursors; Randomized Controlled Trials as Topic; Research Design; Risk; Risk Factors; Stroke; Thrombosis; Treatment Outcome

Natriuretic peptides (NPs) are released from the heart in response to pressure and volume overload. B-type natriuretic peptide (BNP) and N-terminal-proBNP have become important diagnostic tools for assessing patients who present acutely with dyspnea. The NP level reflects a compilation of systolic and diastolic function as well as right ventricular and valvular function. Studies suggest that using NPs in the emergency department can reduce the consumption of hospital resources and can lower costs by either eliminating the need for other, more expensive tests or by establishing an alternative diagnosis that does not require hospital stay. Caveats such as body mass index and renal function must be taken into account when analyzing NP levels. Natriuretic peptide levels have important prognostic value in multiple clinical settings, including in patients with stable coronary artery disease and with acute coronary syndromes. In patients with decompensated heart failure due to volume overload, a treatment-induced drop in wedge pressure is often accompanied by a rapid drop in NP levels. Knowing a patient's NP levels might thus assist with hemodynamic assessment and subsequent treatment titration. Monitoring NP levels in the outpatient setting might also improve patient care and outcomes.

Topics: Atrial Natriuretic Factor; Cardiovascular Diseases; Death, Sudden, Cardiac; Heart Diseases; Heart Failure; Hemodynamics; Humans; Kidney Failure, Chronic; Monitoring, Physiologic; Natriuretic Peptide, Brain; Natriuretic Peptide, C-Type; Obesity; Peptide Fragments; Prognosis; Pulmonary Edema; Pulmonary Embolism; Pulmonary Wedge Pressure; Renal Dialysis; Stroke; Weight Loss

In spite of a significant improvement in control of numerous predisposing risk factors, stroke remains a major health problem and a common cause of death and disability in our societies. Genetic predisposition to stroke development exists and has been documented in both animal models and in humans. However, a precise definition of genetic factors responsible for common forms of stroke is still lacking, mainly due to its complex nature, the confounding presence of other predisposing risk factors, and the genetic heterogeneity of human populations. In contrast, important breakthroughs have been reached for monogenic forms of stroke, such as cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL). An animal model of stroke, the stroke-prone spontaneously hypertensive rat, has provided valuable information on genetic factors involved in stroke predisposition. Among them, the gene-encoding atrial natriuretic peptide has been identified as a stroke gene in both the stroke-prone spontaneously hypertensive rat and, subsequently, in two different human populations. In particular, structural alterations of the gene are consistently present in diseased individuals, suggesting an important role of mutation-dependent mechanisms in stroke predisposition. Finally, the recent use of intermediate disease phenotypes provides a reductionist approach that may contribute to important accumulating information on genes contributing to cerebrovascular accidents.

Topics: Animals; Atrial Natriuretic Factor; Disease Models, Animal; Genetic Linkage; Genetic Predisposition to Disease; Humans; Hypertension; Rats; Risk Factors; Stroke

Background and Purpose- MRproANP (midregional proatrial natriuretic peptide) is known to be independently associated with cardioembolic stroke cause and to improve risk stratification for 90-day mortality when measured within 24 to 72 hours after symptom onset in patients with acute ischemic stroke. However, the optimal time point for assessment remains unclear. This study aimed to evaluate prognostic utility of MRproANP at different time points during the first 5 days of hospitalization in patients with acute ischemic stroke. Methods- Samples of MRproANP were collected on admission (<72 hours after onset) and at multiple time points during the first 5 days of hospitalization in 348 consecutively enrolled patients with acute ischemic stroke. The prognostic value for 90-day mortality, 90-day functional outcome, and the association with cardioembolic stroke cause was assessed regarding the time of measurement, and change over time was modeled using generalized estimating equations. Results- MRproANP levels modestly decease over the initial 5 days but remain highly predictive for cardioembolic stroke cause (odds ratio, 9.75 [95% CI, 3.2-29]; 10.62 [95% CI, 3.4-33.3]; 10.8 [95% CI, 3.1-37.1]; 19.4 [95% CI, 5.49-68.7] on admission, day 1, 3 and 5) and 90-day mortality (odds ratio, 59.4 [95% CI, 7.4-480.7]; 78.3 [95% CI, 7.9-772.6]; 14.5 [95% CI, 1.4-145]; 19.81 [95% CI, 2.7-143.4] on admission, day 1, 3, and 5). Change over time does not significantly modify the prognostic value of MRproANP (

Topics: Acute Disease; Aged; Aged, 80 and over; Atrial Natriuretic Factor; Biomarkers; Female; Humans; Intracranial Embolism; Male; Middle Aged; Patient Admission; Prognosis; Stroke

N-terminal pro-brain natriuretic peptide (NT-proBNP) has been shown to be associated with the prognosis of cardiovascular diseases and NT-proBNP level is elevated in patients with acute ischemic stroke. However, the association between NT-proBNP and poor prognosis after ischemic stroke is still uncertain. The aim of this study was to examine whether serum NT-proBNP is associated with global clinical outcomes in a large cohort of patients with acute ischemic stroke.. Baseline serum NT-proBNP level was measured in a subset of 3126 patients with acute ischemic stroke, and the patients were followed up to assess their clinical outcomes within 1year after the stroke. Cox proportional hazard models and logistic regression models were used to assess the effects of NT-proBNP on the primary outcome (composite outcome of death and vascular events) and poor functional outcomes.. This study showed that high NT-proBNP levels increased the risk of a composite outcome of death and vascular events and poor functional outcomes at 1year after stroke onset among ischemic stroke patients with elevated blood pressure, suggesting that NT-proBNP might be a potential prognostic factor for ischemic stroke.

Topics: Atrial Natriuretic Factor; Biomarkers; Brain Ischemia; Female; Follow-Up Studies; Humans; Incidence; Logistic Models; Male; Middle Aged; Multivariate Analysis; Prognosis; Proportional Hazards Models; Protein Precursors; Stroke; Treatment Outcome

The goal of this study was to identify genetic determinants of plasma N-terminal proatrial natriuretic peptide (NT-proANP) in the general community by performing a large-scale genetic association study and to assess its functional significance in in vitro cell studies and on disease susceptibility.. Genotyping was performed across 16 000 genes in 893 randomly selected individuals, with replication in 891 subjects from the community. Plasma NT-proANP1-98 concentrations were determined using a radioimmunoassay. Thirty-three genome-wide significant single-nucleotide polymorphisms were identified in the MTHFR-CLCN6-NPPA-NPPB locus and were all replicated. To assess the significance, in vitro functional genomic studies and clinical outcomes for carriers of a single-nucleotide polymorphism rs5063 (V32M) located in NPPA that represented the most significant variation in this genetic locus were assessed. The rs5063 variant allozyme in transfected HEK293 cells was decreased to 55±8% of wild-type protein (P=0.01) as assessed by quantitative western blots. Carriers of rs5063 had lower NT-proANP levels (1427 versus 2291 pmol/L; P<0.001) and higher diastolic blood pressures (75 versus 73 mm Hg; P=0.009) and were at an increased risk of stroke when compared with wild-type subjects independent of age, sex, diabetes mellitus, hypertension, atrial fibrillation, and cholesterol levels (hazard ratio, 1.6; P=0.004).. This is the first large-scale genetic association study of circulating NT-proANP levels performed with replication and functional assessment that identified genetic variants in the MTHFR-CLCN6-NPPA-NPPB cluster to be significantly associated with NT-proANP levels. The clinical significance of this variation is related to lower NT-proANP levels, higher blood pressures, and an increased risk of stroke in the general community.

Topics: Atrial Natriuretic Factor; Chloride Channels; Female; Genetic Loci; Genome-Wide Association Study; HEK293 Cells; Humans; Male; Methylenetetrahydrofolate Reductase (NADPH2); Multigene Family; Stroke; White People

This study investigated the efficacy of human atrial natriuretic peptide (hANP, carperitide) for high-risk patients undergoing coronary artery bypass grafting (CABG).. This was a randomized controlled trial of 367 high-risk patients (European System for Cardiac Operative Risk Evaluation above 6) undergoing CABG. The primary endpoint was major adverse cardiovascular and cerebrovascular events (MACCE). Secondary endpoints were (1) postoperative death, (2) MACCE + hemodialysis, and (3) serum creatinine and brain natriuretic peptide (BNP) levels. Logistic regression analysis was conducted to identify preoperative and perioperative factors related to early death and MACCE.. There was no significant difference of survival between the hANP and placebo groups (p = 0.1651), but the MACCE-free rate was significantly higher in the hANP group than in the placebo group (p < 0.0001). No patient from the hANP group started hemodialysis after operation, but 7 patients did in the placebo group, and the dialysis rate was significantly lower in the hANP group (p = 0.0147). Serum creatinine and BNP were also significantly lower in the hANP group at 1 year postoperatively. MACCE were strongly associated with age 75 years or older, chronic kidney disease, hemodialysis, left ventricular dysfunction, and nonuse of carperitide.. In the early postoperative period, carperitide has a cardiorenal protective effect that prevents postoperative MACCE and hemodialysis. Perioperative low-dose carperitide infusion may be useful in high-risk patients undergoing on-pump CABG.

Topics: Aged; Atrial Natriuretic Factor; Cause of Death; Coronary Artery Bypass; Dose-Response Relationship, Drug; Female; Humans; Infusions, Intravenous; Japan; Kidney Failure, Chronic; Male; Postoperative Complications; Preoperative Care; Renal Dialysis; Risk Factors; Stroke; Survival Rate; Treatment Outcome

Atrial fibrillation (AF) is a common arrhythmia; its most prevalent and devastating complication is stroke. A delay of AF onset >48 h is believed to be clinically significant. Mid-regional pro A-type natriuretic peptide (MR-proANP) could be of interest in the identification of the time from onset of AF to presentation.. We measured MR-proANP plasma concentration at presentation in consecutive patients in whom onset of AF was determined, without evidence of concomitant acute heart failure.. Forty-seven patients were included. Patients with an AF onset <48 h (n=19) had decreased MR-proANP concentrations versus patients with onset >48 h (144.0 [129.2-213.7] versus 321.7 [236.4-425.6] pmol/L, p<0.001); MR-proANP was the only independent variable associated with AF <48 h according to multivariate analysis. Area under the ROC curve for identify AF onset <48 h was 0.878 [95%CI 0.778-0.978].. MR-proANP concentration may reliably identify the time from onset of AF to presentation.

Topics: Aged; Aged, 80 and over; Atrial Fibrillation; Atrial Natriuretic Factor; Biomarkers; Female; Heart Failure; Humans; Male; Middle Aged; Multivariate Analysis; Pilot Projects; Predictive Value of Tests; Stroke

The purpose of this study was to examine the prognostic value of midregional pro-atrial natriuretic peptide (MR-proANP) in patients with acute ischemic stroke.. The rapid and reliable estimation of prognosis in acute ischemic stroke is pivotal to optimize clinical care. MR-proANP, a recently described, stable fragment of the ANP precursor hormone, may be useful in this setting.. In a prospective observational study, we measured MR-proANP on admission in plasma of 362 consecutive patients presenting with acute ischemic stroke. The prognostic value of MR-proANP to predict mortality within 90 days and functional outcome (defined as a modified Rankin Scale of ≤2 or ≥3) was evaluated and compared with the National Institutes of Health Stroke Scale (NIHSS) score.. The discriminatory accuracy, calculated with the area under the curve (AUC) of the receiver operating characteristics curve, of MR-proANP to predict death was comparable to the NIHSS (AUC: 0.86 [95% confidence interval (CI): 0.82 to 0.90] and 0.85 [95% CI: 0.81 to 0.89; p = 0.7]). Combined, the accuracy significantly improved (0.92 [95% CI: 0.88 to 0.96; p < 0.01]). The AUC of MR-proANP to predict functional outcome was 0.70 (95% CI: 0.65 to 0.75), similar to the NIHSS (0.75 [95% CI: 0.70 to 0.80]; p = 0.16). The prognostic value of MR-proANP for both outcomes was independent of the NIHSS. Higher MR-proANP concentrations were found in stroke of cardioembolic etiology.. MR-proANP is a prognostic marker in the acute phase of stroke, improving the discriminatory value of the NIHSS, independently predicting post-stroke mortality and functional outcome. (The "COSMOS"-Study [Copeptin in Osmoregulation and Stress Assessment]; NCT00390962).

Topics: Aged; Aged, 80 and over; Atrial Natriuretic Factor; Biomarkers; Brain Ischemia; Female; Humans; Male; Middle Aged; Outcome Assessment, Health Care; Predictive Value of Tests; Prognosis; Prospective Studies; Stroke

Recent evidence from an animal model of stroke, the stroke-prone spontaneously hypertensive rat, implicated the gene encoding atrial natriuretic peptide (ANP) as a possible candidate contributing to the likelihood of experiencing a stroke. The purpose of the present study was to investigate the role of ANP in the pathogenesis of cerebrovascular accidents in humans.. We investigated 2 previously known markers at ANP, G1837A and T2238C, for their possible association with the occurrence of stroke. This was the largest matched case-controlled sample studied thus far; the sample was drawn from a large prospective study (the Physician's Health Study). When assuming a dominant mode of inheritance, a statistically significant positive association was observed for the 1837A allele, indicating an odds ratio of 1.64 (95% confidence interval, 1.01 to 2.65) for stroke. This observation led to the discovery of a new molecular variant in exon 1, G664A, which was responsible for a valine-to-methionine substitution in the proANP peptide. This mutation, which was in linkage disequilibrium with the G1837A marker, was associated with the occurrence of stroke (odds ratio, 2.0; 95% confidence interval, 1.17 to 3.19; P=0.01).. Our findings suggest that molecular variants of the ANP gene may represent an independent risk factor for cerebrovascular accidents in humans. The strong parallelism to the experimental data obtained in the stroke-prone animal model provides assurance for the relevance of our observation.

Topics: Adult; Aged; Aged, 80 and over; Alleles; Animals; Aspirin; Atrial Natriuretic Factor; Base Sequence; Confidence Intervals; Genetic Variation; Humans; Male; Middle Aged; Odds Ratio; Platelet Aggregation Inhibitors; Prospective Studies; Rats; Rats, Inbred SHR; Risk Factors; Stroke; United States; White People

Plasma kallikrein (PKa) has been implicated in contributing to hemorrhage following thrombolytic therapy; however, its role in spontaneous intracerebral hemorrhage is currently not available. This report investigates the role of PKa on hemorrhage and hypertension in stroke-prone spontaneously hypertensive rats (SHRSP). SHRSP were fed with a high salt-containing stroke-prone diet to increase blood pressure and induce intracerebral hemorrhage. The roles of PKa on blood pressure, hemorrhage, and survival in SHRSP were examined in rats receiving a PKa inhibitor or plasma prekallikrein antisense oligonucleotide (PK ASO) compared with rats receiving control ASO. Effects on PKa on the proteolytic cleavage of atrial natriuretic peptide (ANP) were analyzed by tandem mass spectrometry. We show that SHRSP on high-salt diet displayed increased levels of PKa activity compared with control rats. Cleaved kininogen was increased in plasma during stroke compared to SHRSP without stroke. Systemic administration of a PKa inhibitor or PK ASO to SHRSP reduced hemorrhage and blood pressure, and improved neurological function and survival compared with SHRSP receiving control ASO. Since PKa inhibition was associated with reduced blood pressure in hypertensive rats, we investigated the effects of PKa on the cleavage of ANP. Incubation of PKa with ANP resulted in the generation fragment ANP

Topics: Animals; Atrial Natriuretic Factor; Blood Pressure; Cerebral Hemorrhage; Hypertension; Plasma Kallikrein; Rats; Rats, Inbred SHR; Stroke

Topics: Aged; Aged, 80 and over; Atrial Natriuretic Factor; Biomarkers; Brain Ischemia; Disease-Free Survival; Fatty Acid-Binding Proteins; Female; Follow-Up Studies; Growth Differentiation Factor 15; Humans; Magnetic Resonance Imaging; Male; Middle Aged; Natriuretic Peptide, Brain; Neurofilament Proteins; Peptide Fragments; Predictive Value of Tests; Prospective Studies; S100 Proteins; Stroke; Survival Rate; Tomography, X-Ray Computed

Despite many recent advances in medicine, cardiogenic stroke is still a health problem with a high mortality rate. Cardiac biomarkers have been reported to be useful indicators for cardiogenic stroke and subsequent cerebrovascular events. However, there are no data directly comparing the cardiac biomarkers in stroke patients. We measured atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), N-terminal pro-brain natriuretic peptide (NT-proBNP), and high-sensitivity troponin T (hsTnT) levels and performed transthoracic and transesophageal echocardiography in 282 stroke patients. There were 108 cases of cardiogenic stroke and 47 cases of major adverse cardiovascular and cerebrovascular events (MACCE) during the follow-up period. Association with left atrial function and left atrial appendage function appeared somewhat stronger for BNP and NT-proBNP than ANP and hsTnT. Multivariate logistic analysis demonstrated that cardiac biomarkers excluding ANP were significantly associated with cardiogenic stroke in stroke patients, multivariate Cox's proportional hazards regression analysis demonstrated that all biomarkers were significantly associated with MACCE after adjustment for confounding risk factors. Receiver operating characteristic curve analysis showed that the C indices of BNP and NT-proBNP for cardiogenic stroke and MACCE were almost equal, but significantly greater than those of ANP and hsTnT. Both BNP and NT-proBNP levels are useful predictors of cardiogenic stroke and subsequent MACCE superior to ANP and hsTnT in stroke patients.

Topics: Aged; Aged, 80 and over; Atrial Natriuretic Factor; Biomarkers; Echocardiography; Female; Heart; Humans; Japan; Male; Middle Aged; Multivariate Analysis; Natriuretic Peptide, Brain; Peptide Fragments; Prognosis; Prospective Studies; Risk Factors; ROC Curve; Stroke; Survival Analysis

Closure of the left atrial appendage (LAA) to prevent cardioembolic events is an alternative therapy to oral anticoagulation in patients with non-valvular atrial fibrillation. The LAA is an important source of natriuretic peptides and its exclusion from the circulation may alter the blood level of these hormones, thereby influencing their diagnostic value and clinical effects.. We aimed to prospectively assess potential changes in mid-regional pro A-type natriuretic peptide (MR-proANP) and N-terminal pro B-type natriuretic peptide (NT-proBNP) levels 6 weeks and 6 months after interventional LAA closure using the WATCHMAN device.. In 29 consecutive patients with successful LAA closure baseline MR-proANP level was 274±208pmol/l and decreased by -24.5±68 (p=0.07) and -15.0±44pmol/l (p=0.10) after 6 weeks and 6 months, respectively. The drop in the MR-proANP level after 6 weeks and 6 months was significant in patients with elevated (≥214pmol/l) baseline MR-proANP level (n=15: -54.3±78.0, p<0.01 and -31.8±45.4pmol/l, p=0.03, respectively) and those with reduced left ventricular ejection fraction (LVEF<45%, n=7: -87.4±97.3, p=0.02 and -60.3±42.6pmol/l, p=0.01, respectively). Baseline NT-proBNP level (median 1054pg/ml; IQR 621-1977pg/ml), sodium, potassium, mean systolic or diastolic blood pressure did not change significantly in the mentioned patient groups.. After LAA closure, MR-proANP level decreased significantly in patients with elevated baseline MR-proANP level or reduced LVEF, whereas NT-proBNP level remained unchanged, thereby altering the correlation coefficient between the two biomarkers. Our findings should be considered when using these biomarkers for diagnostic or prognostic evaluation in patients with interventional LAA closure.

Topics: Aged; Atrial Appendage; Atrial Fibrillation; Atrial Natriuretic Factor; Biomarkers; Cardiac Surgical Procedures; Echocardiography, Transesophageal; Electrocardiography; Female; Follow-Up Studies; Humans; Male; Natriuretic Peptide, Brain; Peptide Fragments; Prognosis; Prospective Studies; Protein Precursors; Septal Occluder Device; Stroke

To validate midregional proatrial natriuretic peptide (MR-proANP) for outcome prediction and diagnosis of cardioembolic stroke etiology compared to established clinical variables.. In this prospective multicenter cohort study, we quantified MR-proANP levels in ischemic stroke patients within 24 hours of onset. Primary outcome measures were 90-day mortality, unfavorable functional outcome (modified Rankin Scale score >2), and cardioembolic stroke etiology diagnosed during hospitalization.. MR-proANP is a newly validated blood biomarker providing additional prognostic information for mortality after stroke. Higher MR-proANP levels were associated with cardioembolic stroke etiology and, even more strongly, atrial fibrillation.

Topics: Aged; Aged, 80 and over; Atrial Natriuretic Factor; Brain Ischemia; Cohort Studies; Disability Evaluation; Female; Humans; Magnetic Resonance Imaging; Male; Middle Aged; Predictive Value of Tests; ROC Curve; Stroke; Treatment Outcome

The combination of AT1 blocker/neutroendopeptidase neprilysin inhibition (ARNi) represents an interesting approach to reduce cardiovascular risk in hypertension. We assessed the efficacy of ARNi, compared with angiotensin II type 1 receptor blockade alone, on blood pressure (BP) and on protection from target organ damage development in the stroke-prone spontaneously hypertensive rat (SHRSP).. In high-salt fed SHRSP, we assessed plasma and tissue natriuretic peptides, urinary volume, BP and body weight over a short-term treatment (6 weeks) with either ARNi (sacubitril/valsartan 68 mg/kg per day) or valsartan (30 mg/kg per day), protection from stroke and renal damage (as documented by proteinuria) over 4 months of treatment with either sacubitril/valsartan or valsartan; the ability of either treatment to reduce progression of cerebrovascular and renal damage after 2 weeks of high-salt diet.. Higher levels of plasma and tissue atrial natriuretic peptide, of urinary cyclic guanosine 3'5'monophosphate and urine volumes, along with lower BP levels, were found upon sacubitril/valsartan as compared with valsartan over the short-term treatment. Sacubitril/valsartan caused a significant reduction of both BP and proteinuria levels and complete prevention of stroke over the long-term treatment. Once organ damage was established, a significant delay of its progression was observed with sacubitril/valsartan.. The dual angiotensin II type 1 receptor/neutroendopeptidase inhibition significantly increased atrial natriuretic peptide level and reduced BP. Complete prevention of stroke was achieved in this model. The ability of sacubitril/valsartan to reduce organ damage progression was superior to that of valsartan alone. ARNi may represent a highly effective therapeutic agent to protect from target organ damage development in hypertension.

Topics: Aminobutyrates; Angiotensin II Type 1 Receptor Blockers; Animals; Antihypertensive Agents; Atrial Natriuretic Factor; Biphenyl Compounds; Blood Pressure; Cyclic GMP; Drug Combinations; Hypertension; Male; Neprilysin; Proteinuria; Rats; Rats, Inbred SHR; Stroke; Tetrazoles; Valsartan

To investigate the relationships among aldosterone level, use of antihypertensive (anti-HTN) medications, clinical profile, and atrial natriuretic peptide (ANP) level in individuals with HTN.. In a community-based cohort, we analyzed aldosterone plasma levels based on the presence (n=477) or absence (n=1073) of HTN. In individuals with HTN, we evaluated circulating aldosterone levels according to the number of anti-HTN drugs used, analyzed the associated clinical characteristics, and determined the relationship to the counterregulatory cardiac hormone ANP. Data were collected from August 25, 1997, through September 5, 2000.. Participants with HTN had higher serum aldosterone levels than those without HTN (6.4 vs 4.1 ng/dL [to convert to pmol/L, multiply by 27.74]; P<.001). When individuals with HTN were stratified according to the number of anti-HTN medications used, the increase in number of medications (0, 1, 2, and ≥3) was associated with higher aldosterone levels (4.8, 6.4, 7.10, and 7.9 ng/dL, respectively; P=.002), worse metabolic profile, and higher prevalence of cardiovascular, renal, and metabolic disease. In participants with HTN, ANP plasma levels were inversely related to aldosterone levels when the latter was divided into tertiles.. In this randomly selected general population cohort, aldosterone levels were higher in individuals with HTN compared with normotensive participants. Aldosterone levels increased with anti-HTN medication use. These findings also suggest a relative ANP deficiency with increasing aldosterone levels and anti-HTN drug use. These studies have pathophysiologic and therapeutic implications for targeting aldosterone in the clinical treatment of HTN.

Topics: Aged; Aldosterone; Antihypertensive Agents; Atrial Natriuretic Factor; Blood Glucose; Cholesterol, LDL; Cohort Studies; Coronary Artery Disease; Diuretics; Female; Glomerular Filtration Rate; Heart Failure; Humans; Hypertension; Hypertrophy, Left Ventricular; Hypolipidemic Agents; Insulin; Male; Metabolic Syndrome; Middle Aged; Minnesota; Myocardial Infarction; Obesity; Sampling Studies; Stroke; Triglycerides

Topics: Adrenomedullin; Adult; Aged; Ankle Brachial Index; Anticoagulants; Asymptomatic Diseases; Atrial Fibrillation; Atrial Natriuretic Factor; C-Reactive Protein; Cardiovascular Diseases; Carotid Intima-Media Thickness; Female; Fibrinogen; Germany; Humans; Male; Middle Aged; Natriuretic Peptide, Brain; Peptide Fragments; Phenprocoumon; Protein Precursors; Pulmonary Embolism; Risk Factors; Stroke; Stroke Volume; Vascular Stiffness; Venous Thrombosis; Warfarin

Paroxysmal atrial fibrillation (PAF) is often asymptomatic but nonetheless harmful. We evaluated the performance of disease-related blood biomarkers and CHA2DS2-VASc score to discriminate for PAF in patients with continuous rhythm monitoring.. Clinical data and blood samples were obtained from patients with dual-chamber pacemakers selected according to the absence (no_AHRE) or presence of Atrial High-Rate Episodes (AHRE) >6 min in recent device history (case-control approach). We included 93 patients (n = 49 AHRE, n = 44 no_AHRE). In a subgroup with high AHRE burden and confirmed PAF 15 biomarkers were evaluated (n = 19 AHRE-AF vs. n = 20 no_AHRE). Significantly regulated biomarkers were then tested in all patients to distinguish no_AHRE from AHRE (receiver operating characteristics analysis). Hsp27, TGFβ1, cystatin C, matrix metalloproteinases MMP-2,-3,-9, albumin, and serum uric acid were not altered in the subgroup. Tissue inhibitors of metalloproteinases (TIMP) -1,-2,-4; NT-proANP, NT-proBNP, IL-6 and serum amyloid protein A were significantly different in AHRE vs. no_AHRE (subgroup and whole cohort), with best discriminatory performance for TIMP-4. Biomarkers performed better than CHADS2-VASc for AHRE discrimination. Intracardial electrograms and medical history from seven AHRE patients suggested atrial tachycardia and not AF (AHRE-AT). Four of the most relevant regulated biomarkers (TIMP-4, TIMP-2, SAA, NT-proBNP) behaved similarly in AHRE-AT and AHRE-AF. NT-proBNP >150 pg/mL indicated an odds ratio of 12.9 for AHRE. Combining two biomarkers significantly improved discrimination of AHRE.. TIMP-4, NT-proANP, NT-proBNP were strongest associated with PAF and AHRE. The discriminatory performance of CHADS2-VASc for PAF was increased by addition of selected biomarkers.

Topics: Aged; Aged, 80 and over; Atrial Fibrillation; Atrial Natriuretic Factor; Biomarkers; Causality; Comorbidity; Electrocardiography; Female; Germany; Humans; Incidence; Interleukin-6; Male; Natriuretic Peptide, Brain; Peptide Fragments; Reproducibility of Results; Risk Assessment; Sensitivity and Specificity; Serum Amyloid A Protein; Stroke; Tissue Inhibitor of Metalloproteinase-4; Tissue Inhibitor of Metalloproteinases

Topics: Atrial Fibrillation; Atrial Natriuretic Factor; Biomarkers; Humans; Natriuretic Peptide, Brain; Peptide Fragments; Stroke

Functional imaging studies have argued that interactions between cortical motor areas and the cerebellum are relevant for motor output and recovery processes after stroke. However, the impact of the underlying structural connections is poorly understood. To investigate this, diffusion-weighted brain imaging was conducted in 26 well-characterized chronic stroke patients (aged 63 ± 1.9 years, 18 males) with supratentorial ischemic lesions and 26 healthy participants. Probabilistic tractography was used to reconstruct reciprocal cortico-cerebellar tracts and to relate their microstructural integrity to residual motor functioning applying linear regression modeling. The main finding was a significant association between cortico-cerebellar structural connectivity and residual motor function, independent from the level of damage to the cortico-spinal tract. Specifically, white matter integrity of the cerebellar outflow tract, the dentato-thalamo-cortical tract, was positively related to both general motor output and fine motor skills. Additionally, the integrity of the descending cortico-ponto-cerebellar tract contributed to rather fine motor skills. A comparable structure-function relationship was not evident in the controls. The present study provides first tract-related structural data demonstrating a critical importance of distinct cortico-cerebellar connections for motor output after stroke.

Topics: Aged; Atrial Natriuretic Factor; Brain Ischemia; Cerebellum; Cerebral Cortex; Chronic Disease; Diffusion Magnetic Resonance Imaging; Diffusion Tensor Imaging; Female; Humans; Linear Models; Male; Middle Aged; Motor Activity; Neural Pathways; Stroke; White Matter

The impact of atrial natriuretic peptide (ANP) value for predicting paroxysmal atrial fibrillation (pAF) in ischemic stroke patients remains uncertain.. The consecutive 222 ischemic stroke patients (median 77 [IQR 68-83] years old, 93 females) within 48 hours after onset were retrospectively studied. Plasma ANP and brain natriuretic peptide (BNP) levels were simultaneously measured at admission. Of all, 158 patients had no evidence of atrial fibrillation (AF) (sinus rhythm [SR] group), 25 patients had pAF (pAF group), and the other 39 patients had chronic AF (cAF group). We investigated predicting factors for pAF, with focus on ANP, BNP, and ANP/BNP ratio.. ANP value was significantly higher in the pAF than in the SR group (97 [50-157] mg/dL versus 42 [26-72] mg/dL, P < .05) and further increased in the cAF group (228 [120-392], P < .05 versus pAF and SR groups). Similarly, the BNP value was higher in the pAF than in the SR group (116 [70-238] mg/dL versus 34 [14-72] mg/dL, P < .05) and further increased in the cAF group (269 [199-423], P < .05 versus pAF and SR groups). ANP/BNP ratio was lower in the pAF and cAF groups than in the SR group (.6 [.5-1.2] and .7 [.5-1.0] versus 1.3 [.8-2.4], both P < .05]. Multivariate analysis in the SR and pAF groups (n = 183) demonstrated that age, congestive heart failure, ANP, and BNP, but not ANP/BNP ratio, were independent predictors for detecting pAF. Receiver operating characteristic curve analysis further showed that area under the curve was similar between ANP and BNP (.76 and .80).. ANPmay be clinically useful for detecting pAF in ischemic stroke patients as well as BNP.

Topics: Aged; Aged, 80 and over; Atrial Fibrillation; Atrial Natriuretic Factor; Brain Ischemia; Female; Humans; Male; Multivariate Analysis; Predictive Value of Tests; Retrospective Studies; ROC Curve; Severity of Illness Index; Stroke

Black subjects tend to retain salt and water, be more sensitive to aldosterone, and have suppression of plasma renin activity. Variants of the renal sodium channel (ENaC, SCNN1B) account for approximately 6% of resistant hypertension (RHT) in Blacks; other candidate genes may be important.. Six candidate genes associated with low renin-resistant hypertension were sequenced in Black Africans from clinics in Kenya and South Africa. CYP11B2 was sequenced if the aldosterone level was high (primary aldosteronism phenotype); SCNN1B, NEDD4L, GRK4, UMOD, and NPPA genes were sequenced if the aldosterone level was low (Liddle phenotype).. There were 14 nonsynonymous variants (NSVs) of CYP11B2: 3 previously described and associated with alterations in aldosterone synthase production (R87G, V386A, and G435S). Out of 14, 9 variants were found in all 9 patients sequenced. There were 4 NSV of GRK4 (R65L, A116T, A142V, V486A): at least one was found in all 9 patients; 3 were previously described and associated with hypertension. There were 3 NSV of SCNN1B (R206Q, G442V, and R563Q); 2 previously described and 1 associated with hypertension. NPPA was found to have 1 NSV (V32M), not previously described and NEDD4L did not have any variants. UMOD had 3 NSV: D25G, L180V, and T585I.. A phenotypic approach to investigating the genetic architecture of RHT uncovered a surprisingly high yield of variants in candidate genes. These preliminary findings suggest that this novel approach may assist in understanding the genetic architecture of RHT in Blacks and explain their two fold risk of stroke.

Topics: Adult; Aged; Aldosterone; Atrial Natriuretic Factor; Black People; Blood Pressure; Cytochrome P-450 CYP11B2; Endosomal Sorting Complexes Required for Transport; Epithelial Sodium Channels; Female; G-Protein-Coupled Receptor Kinase 4; Gene Frequency; Genetic Association Studies; Genetic Markers; Genetic Predisposition to Disease; Genetic Variation; Humans; Hypertension; Kenya; Male; Middle Aged; Nedd4 Ubiquitin Protein Ligases; Phenotype; Prognosis; Renin; Renin-Angiotensin System; Risk Assessment; Risk Factors; South Africa; Stroke; Ubiquitin-Protein Ligases; Uromodulin

Chronic infections and neuroendocrine dysfunction may be risk factors for ischemic stroke (IS). We hypothesized that selected blood biomarkers of infection (procalcitonin [PCT]), hypothalamic-pituitary-axis function (copeptin), and hemodynamic dysfunction (midregional proatrial natriuretic peptide [MRproANP]) are associated with incident IS risk in the multiethnic, urban Northern Manhattan Study (NOMAS) cohort.. A nested case-control study was performed among initially stroke-free participants. Cases were defined as first IS (n=172). We randomly selected controls among those who did not develop an event (n=344). We calculated Cox proportional hazards models with inverse probability weighting to estimate the association of blood biomarkers with risk of stroke after adjusting for demographic, behavioral, and medical risk factors.. Those with PCT and MRproANP, but not copeptin, in the top quartile, compared with the lowest quartile, were associated with IS (for PCT adjusted hazard ratio [HR], 1.9; 95% confidence interval [CI], 1.0-3.8 and for MRproANP adjusted HR, 3.5; 95% CI, 1.6-7.5). The associations of PCT and MRproANP differed by stroke etiology; PCT levels in the top quartile were particularly associated with small vessel stroke (adjusted HR, 5.1; 95% CI, 1.4-18.7) and MRproANP levels with cardioembolic stroke (adjusted HR, 16.3; 95% CI, 3.7-70.9).. Higher levels of PCT, a marker of infection, and MRproANP, a marker for hemodynamic stress, were independently associated with IS risk. PCT was specifically associated with small vessel and MRproANP with cardioembolic stroke risk. Further study is needed to validate these biomarkers and determine their significance in stroke risk prediction and prevention.

Topics: Aged; Atrial Natriuretic Factor; Biomarkers; Brain Ischemia; Calcitonin; Case-Control Studies; Female; Glycopeptides; Humans; Male; Middle Aged; Risk Factors; Stroke

Atrial natriuretic peptide (ANP) is released from the atria (on cleavage of proANP) in response to elevated intra-atrial pressure and wall stretch. Clinical data on proANP are still limited, mainly due to limitations in assaying the protein, which recently have been solved. ProANP is elevated in cardiovascular disease and predicts outcome in heart failure. However, knowledge of the prognostic value in acute myocardial infarction remains limited.. We prospectively included 680 patients with STEMI treated with primary-PCI, from September 2006 to December 2008. Blood samples were drawn immediately before PCI. Plasma MR-proANP was measured using an automated processing assay. Endpoints were all-cause mortality (n = 137) and the combined endpoint (n = 170) of major adverse cardiovascular events (MACE) defined as cardiovascular mortality and admission due to recurrent MI, ischaemic stroke or heart failure.. During 5-year follow-up, MR-proANP was associated with increased risk of all-cause mortality and MACE (both p < 0.001). After adjustment for confounding risk factors (age, gender, hypertension, diabetes, hypercholesterolaemia, smoking, previous MI, BMI, eGFR, CRP, peak-TnI, symptom-to-balloon time, multivessel disease, complex lesion, LAD-lesion and use of glycoprotein inhibitor), MR-proANP remained an independent predictor of all-cause mortality and MACE - hazard ratio: 1.68 (95% CI 1.35-2.10; p < 0.001) and 1.68 (95% CI 1.39-2.03; p < 0.001) per standard deviation increase in MR-proANP. MR-proANP significantly increased C-statistics and reclassified 26% of the patients for all-cause mortality and 34% for MACE into higher or lower risk categories, matching actual event rates more accurately.. Plasma MR-proANP independently predicts all-cause mortality and MACE in patients with STEMI.

Topics: Aged; Area Under Curve; Atrial Natriuretic Factor; Biomarkers; C-Reactive Protein; Cause of Death; Female; Heart Failure; Humans; Kaplan-Meier Estimate; Male; Middle Aged; Myocardial Infarction; Patient Readmission; Percutaneous Coronary Intervention; Predictive Value of Tests; Proportional Hazards Models; Prospective Studies; Recurrence; Risk Assessment; Risk Factors; ROC Curve; Stroke; Stroke Volume; Time Factors; Treatment Outcome; Troponin I; Up-Regulation; Ventricular Function, Left

Atrial natriuretic peptide (ANP) is a well-known prognostic marker of outcome and mortality in patients with cardiovascular disease. Midregional proatrial natriuretic peptide (MR-proANP) is a stable fragment of the ANP precursor hormone. As a prognostic marker after ischemic stroke, it reliably predicts poststroke mortality and functional outcome. This study aimed to analyze the prognostic value of MR-proANP in patients with hemorrhagic stroke, i.e. subarachnoid (SAH) and intracerebral hemorrhage (ICH).. MR-proANP was analyzed in patients with spontaneous SAH or spontaneous ICH. All patients were prospectively randomized into two treatment arms: (1) a prophylactic normothermia group with a target core temperature 36.5°C using endovascular cooling, and (2) a control group with conventional stepwise predefined fever management using antipyretic medication and surface cooling. Blood samples were obtained on admission and on days 4 and 7. Measurement of MR-proANP was performed in serum using sandwich immunoassay. The primary endpoint was functional outcome [assessed by the Glasgow Outcome Score (GOS)] and the secondary endpoints were mortality within 180 days after hemorrhagic stroke and influence of temperature on MR-proANP. A favorable outcome was defined as GOS 4-5, and the patients were considered to have a poor outcome with a 180-day GOS score between 1 and 3.. Analysis of MR-proANP was performed in 24 patients with spontaneous SAH and 22 patients with spontaneous ICH. MR-proANP was elevated on days 4 and 7 as compared to baseline levels (p < 0.05 and p < 0.001, respectively). High MR-proANP levels (>120 pmol/l) were associated with increased mortality and poor outcome (after 180 days; p < 0.05, respectively). There was no significant difference regarding MR-proANP serum concentrations between the endovascular and the control groups.. Increased levels of MR-proANP are independently associated with poor functional outcome and increased mortality after 180 days in patients with hemorrhagic stroke. Endovascular temperature control had no significant influence on MR-proANP levels.

Topics: Adult; Aged; Aged, 80 and over; Atrial Natriuretic Factor; Biomarkers; Female; Humans; Intracranial Hemorrhages; Male; Middle Aged; Predictive Value of Tests; Prognosis; Prospective Studies; Recovery of Function; Stroke

In this study, we assessed the relationship of insular strokes and plasma MR-proANP levels with newly diagnosed atrial fibrillation (NDAF).. This study is based on a prospective acute stroke cohort (http://www.clinicaltrials.gov, NCT00390962). Patient eligibility was dependent on the diagnosis of acute ischemic stroke, absence of previous stroke based on past medical history and MRI, no history of AF and congestive heart failure (cohort A) and, additionally, no stroke lesion size ≥ 20 mL (sub-cohort A*). AF, the primary endpoint, was detected on 24-hour electrocardiography and/or echocardiography. Involvement of the insula was assessed by two experienced readers on MRI blinded to clinical data. MR-proANP levels were obtained through a novel sandwich immunoassay. Logistic-regression-models were fitted to estimate odds ratios for the association of insular strokes and MR-proANP with NDAF. The discriminatory accuracy of insular strokes and MR-proANP was assessed by a model-wise comparison of the area under the receiver-operating-characteristics-curve (AUC) with known predictors of AF.. 104 (cohort A) and 83 (cohort A*) patients fulfilled above-mentioned criteria. Patients with isolated insular strokes had a 10.7-fold higher odds of NDAF than patients with a small ischemic stroke at any other location. The AUC of multivariate logistic regression models for the prediction of NDAF improved significantly when adding stroke location and MR-proANP levels. Moreover, MR-proANP levels remained significantly elevated throughout the acute hospitalization period in patients with NDAF compared to those without.. Isolated insular strokes and plasma MR-proANP levels on admission are independent predictors of NDAF and significantly improve the prediction accuracy of identifying patients with NDAF compared to known predictors including age, the NIHSS and lesion size. To accelerate accurate diagnosis and enhance secondary prevention in acute stroke, higher levels of MR-proANP and insular strokes may represent easily accessible indicators of AF if confirmed in an independent validation cohort.

Topics: Aged; Aged, 80 and over; Atrial Fibrillation; Atrial Natriuretic Factor; Female; Humans; Male; Middle Aged; Pilot Projects; Prospective Studies; Stroke

Clinical scores are recommended for predicting cardiovascular risk in patients with cerebral ischaemia to inform secondary prevention. Blood biomarkers may improve prediction beyond clinical scores.. Within the observational Find-AF trial (ISRCTN46104198), 197 patients >18 years of age with cerebral ischaemia and without atrial fibrillation had blood sampled at baseline. The predictive value of five biomarkers for a combined vascular endpoint (acute coronary syndrome, stroke, cardiovascular death) and all-cause mortality was determined, alone and in addition to the Essen Stroke Risk Score (ESRS), Stroke Prognostic Instrument 2 (SPI-2) and National Institutes of Health Stroke Scale (NIH-SS).. There were 23 vascular events (11.7%) and 13 deaths (6.6%) to 1 year follow-up. In multivariate analyses of all markers, only high-sensitivity troponin T (hsTropT) remained independently predictive for vascular events (p=0.045) and all-cause mortality (p=0.004). hsTropT was higher in patients with a vascular event (median 12.7 ng/ml vs 5.1 ng/ml), and patients with hsTropT above the median of 6.15 ng/ml had vascular events more frequently (HR 3.86, p=0.008). For prediction of vascular events as well as all-cause mortality, hsTropT significantly improved multivariate Cox regression models with ESRS, SPI-2 or NIH-SS. The c-statistic increased non-significantly from 0.695 (ESRS) or 0.710 (hsTropT) to 0.747 (ESRS+hsTropT) and from 0.699 (SPI-2) to 0.763 (SPI-2+hsTropT). No patient with a low-risk ESRS and an hsTropT below the median had a vascular event or died.. hsTropT predicts vascular events and all-cause mortality in patients with acute cerebral ischaemia and improves prediction beyond established clinical scores.

Topics: Aged; Atrial Natriuretic Factor; Biomarkers; Brain Ischemia; Cardiovascular Diseases; Cohort Studies; Endpoint Determination; Fatty Acid Binding Protein 3; Fatty Acid-Binding Proteins; Female; Follow-Up Studies; Growth Differentiation Factor 15; Humans; Ischemic Attack, Transient; Kaplan-Meier Estimate; Male; Middle Aged; Natriuretic Peptide, Brain; Peptide Fragments; Predictive Value of Tests; Prognosis; Prospective Studies; Risk Assessment; Stroke; Survival Analysis; Troponin; Troponin T

Atrial natriuretic peptide (ANP, also known as NPPA) and brain natriuretic peptide (BNP, also known as NPPB) have been determined as genetic factors for several diseases, including stroke and myocardial infarction, in human and rat models. To investigate the potential association between polymorphisms of the NPPA gene and stroke in a Korean population, nine single-nucleotide polymorphisms (SNPs) of NPPA and NPPB genes were genotyped in a total of 941 Korean subjects, including 674 stroke patients (109 hemorrhagic and 565 ischemic) and 267 unaffected controls. Genotype comparisons of the targeted alleles revealed that there were no significant associations between stroke patients and control subjects, or among hemorrhagic, ischemic, and control groups. However, in logistic analysis for Trial of Org 10172 in Acute Stroke Treatment (TOAST) classification of ischemic stroke, nonsynonymous rs5065 (STOP152Arg) and rs5067 in 3'UTR of NPPA, which were in complete linkage disequilibrium, showed significant associations with cardioembolic stroke. These two SNPs showed higher frequencies in cardioembolic stroke patients than those in controls and ischemic patients with small-vessel occlusion (p=0.002, adjusted p=0.02). It was also found that NPPA rs5065C allele in all of the Korean subjects existed as heterozygous compared with Caucasian and African populations. Although further replications in larger cardioembolic stroke subjects are required, our preliminary findings suggest that the nonsynonymous rs5065C of the NPPA gene, which could produce a new or dysfunctional transcript, is possibly associated with cardioembolism.

Topics: Aged; Atrial Natriuretic Factor; Case-Control Studies; Coronary Disease; Embolism; Female; Genotype; Humans; Male; Middle Aged; Polymorphism, Single Nucleotide; Stroke

Topics: Acute Disease; Adult; Aged; Aged, 80 and over; Atrial Natriuretic Factor; Female; Heart Diseases; Humans; Kaplan-Meier Estimate; Male; Middle Aged; Pilot Projects; Predictive Value of Tests; Protein Precursors; Risk Factors; Stroke

The renin-angiotensin and sympathetic nervous systems play critical interlinked roles in the development of left ventricular hypertrophy, fibrosis, and dysfunction. These studies investigated the hemodynamic and cardiac effects of monoblockade and coblockade of renin-angiotensin and sympathetic nervous systems. Stroke-prone spontaneously hypertensive rats (16 weeks old; male; n=12 per group) received the sympatholytic imidazoline compound, moxonidine (2.4 mg/kg per day); the angiotensin-receptor blocker eprosartan (30 mg/kg per day), separately or in combination; or saline vehicle for 8 weeks, SC, via osmotic minipumps. Blood pressure and heart rate were continuously measured by radiotelemetry. After 8 weeks, in vivo cardiac function and structure were measured by transthoracic echocardiography and a Millar conductance catheter, and the rats were then euthanized and blood and heart ventricles collected for various determinations. Compared with vehicle, the subhypotensive dose of moxonidine resulted in lower (P<0.01) heart rate, left ventricular hypertrophy, cardiomyocyte cross-sectional area, interleukin 1 beta, tumor necrosis factor-alpha, and mRNA for natriuretic peptides. Eprosartan reduced pressure (P<0.01), as well as extracellular signal-regulated kinase (ERK) 44 phosphorylation, Bax/Bcl-2, and collagen I/III, and improved left ventricular diastolic function (P<0.03). Combined treatment resulted in greater reductions in blood pressure, heart rate, left ventricular hypertrophy, collagen I/III, and inhibited inducible NO synthase and increased endothelial NO synthase phosphorylation, as well as reduced left ventricular anterior wall thickness, without altering the other parameters. Thus, in advanced hypertension complicated with cardiac fibrosis, sympathetic inhibition and angiotensin II blockade resulted in greater reduction in blood pressure and heart rate, inhibition of inflammation, and improved left ventricular pathology but did not add to the benefits of angiotensin II blockade on cardiac function.

Topics: Acrylates; Animals; Antihypertensive Agents; Atrial Natriuretic Factor; Blood Pressure; Heart Rate; Hypertension; Imidazoles; Male; Nitric Oxide Synthase Type III; Phosphorylation; Rats; Rats, Inbred SHR; Stroke; Thiophenes; Ventricular Function, Left

Risk stratification for cardiovascular outcomes is gaining importance in general population. Prognostic value of natriuretic peptides has been established in patients with heart failure. However, the prognostic significance of natriuretic peptides with respect to stroke is not well known in general populations.. Plasma natriuretic peptides were measured in a representative population-based sample of 958 men (age 46-65 years) from Eastern Finland. There were 46 cases of stroke, 74 of atrial fibrillation and 31 cases of ischaemic strokes during a follow-up of 9.6 years.. The multivariable adjusted risk was 1.35-fold (95% CI 1.01 to 1.84, p = 0.049) for any stroke and 1.30-fold (95% CI 0.90 to 1.91, p = 0.0150) for ischaemic stroke for each log-transformed SD (0.240 pmol/l) increment in N-terminal fragment of proA-type natriuretic peptide. The respective risks were 1.36-fold (95% CI 1.05 to 1.76, p = 0.010) and 1.50-fold (95% CI 1.12 to 2.02, p = 0.007) for each log-transformed SD (0.237 pmol/l) increment in N-terminal fragment of proB-type natriuretic peptide. The multivariate adjusted risks for future atrial fibrillation were 1.71 (95% CI 1.32 to 2.22, p<0.001) and 1.68-fold (95% CI 1.38 to 2.07, p<0.001) for each log-transformed SD increment in N-terminal fragments of proA- and proB-type natriuretic peptides, respectively.. N-terminal fragments of pro-atrial natriuretic peptide and pro-brain natriuretic peptide are new additional predictors of any stroke and atrial fibrillation. Natriuretic peptides provide prognostic information for stroke and atrial fibrillation and may help in identifying subjects at risk for stroke and atrial fibrillation.

Topics: Aged; Atrial Fibrillation; Atrial Natriuretic Factor; Biomarkers; Follow-Up Studies; Humans; Male; Middle Aged; Natriuretic Peptide, Brain; Natriuretic Peptides; Peptide Fragments; Prognosis; Protein Precursors; Risk Assessment; Stroke

Previous studies in a hypertensive animal model of stroke and in humans showed that mutations of the atrial natriuretic peptide (ANP) gene are associated with increased risk of stroke. To elucidate the vascular disease mechanisms that result from structural modifications of the ANP gene, we investigated a coding mutation of the ANP gene in stroke-prone spontaneously hypertensive rats (SHRsp). This mutation leads to a Gly/Ser transposition in the prosegment of ANP. We found that presence of this mutation is associated with increased immunostaining of ANP in the wall of SHRsp cerebral vessels. The mutation causes a major inhibitory effect on endothelial cell proliferation, as assessed by thymidine incorporation, and on angiogenesis, as determined by an endothelial cell tube formation assay, in human umbilical vein endothelial cells (HUVEC) exposed to ANP/SHRsp. These in vitro findings show that the SHRsp-derived form of ANP has an inhibitory effect on vascular remodeling and they provide further support for a role of the ANP gene in the pathogenesis of cerebrovascular disease in the animal model.

Topics: Animals; Atrial Natriuretic Factor; Cell Line; Cell Proliferation; Culture Media, Conditioned; Disease Models, Animal; Endothelium, Vascular; Gene Expression Regulation; Humans; Hypothalamus; Mutation; Rats; Rats, Inbred SHR; Stroke; Transfection; Umbilical Veins

Measurement of natriuretic peptides provides prognostic information in various patient populations. The prognostic value of natriuretic peptides among patients with acute stroke is not known, although elevated peptide levels have been observed.. A series of 51 patients (mean age, 68+/-11 years) with first-ever ischemic stroke underwent a comprehensive clinical examination and measurements of plasma atrial natriuretic peptides (N-ANP) and brain natriuretic peptides (N-BNP) in the acute phase of stroke. The patients were followed-up for 44+/-21 months. Risk factors for all-cause mortality were assessed. Control populations, matched for gender and age, consisted of 51 patients with acute myocardial infarction (AMI) and 25 healthy subjects.. Plasma concentrations of N-ANP (mean+/-SD, 988+/-993 pmol/L) and N-BNP (751+/-1608 pmol/L) in the stroke patients were at the same level as those in the AMI patients (NS for both), but significantly higher than those of the healthy subjects (358+/-103 pmol/L, P<0.001 and 54+/-26 pmol/L, P<0.01, respectively). Elevated levels of N-ANP and N-BNP predicted mortality after stroke (risk ratio [RR] 4.3, P<0.01 and RR 3.9, P<0.01, respectively) and after AMI (P<0.05), and remained independent predictors of death after stroke even after adjustment for age, diabetes, coronary artery disease, and medication (RR 3.9, P<0.05 and RR 3.7, P<0.05, respectively).. Plasma levels of natriuretic peptides are elevated in the acute phase of stroke and predict poststroke mortality.

Topics: Aged; Atrial Natriuretic Factor; Brain Infarction; Case-Control Studies; Female; Humans; Male; Natriuretic Peptide, Brain; Nerve Tissue Proteins; Peptide Fragments; Prognosis; Prospective Studies; Protein Precursors; Risk Factors; Stroke

A precise definition of genetic factors responsible for common forms of stroke is still lacking. The purpose of the present study was to investigate the contributory role of the genes encoding atrial natriuretic peptide (ANP) and type A natriuretic peptide receptor (NPRA) in humans' susceptibility to develop ischemic stroke.. Allele and genotype frequencies of ANP and NPRA were characterized in an Italian case-control study with patients affected by vascular disease or risk factors. Subjects were recruited from the island of Sardinia (206 cases, 236 controls).. A significant association between the ANP/TC2238 polymorphic site and stroke occurrence was found when a recessive model of inheritance was assumed. The risk conferred by this mutant genotype, when estimated by multivariate logistic regression analysis, was 3.8 (95% confidence interval, 1.4 to 10.9). A significantly increased risk of stroke recurrence was observed among cases carrying the ANP/CC2238 genotype compared with cases carrying the ANP/TT2238 genotype (P=0.04). No direct association of NPRA with stroke occurrence was detected. However, a significant epistatic interaction between the ANP/CC2238 genotype and an allelic variant of NPRA led to a 5.5-fold increased risk of stroke (95% confidence interval, 1.5 to 19.4).. Our findings support a direct contributory role of ANP to stroke in humans. A significant interaction between ANP and NPRA on stroke occurrence was found.

Topics: Aged; Atrial Natriuretic Factor; Brain Ischemia; Case-Control Studies; Female; Gene Frequency; Genetic Predisposition to Disease; Genotype; Guanylate Cyclase; Humans; Male; Middle Aged; Mutation; Polymorphism, Genetic; Receptors, Atrial Natriuretic Factor; Recurrence; Stroke

Calcium-dependent mechanisms and the renin angiotensin system (RAS) are critically involved in the hypertrophic growth of the myocardium. The calcium/calmodulin-dependent protein kinase II (CaMKII) is a ubiquitous mediator in calcium signaling and modulates calcium handling and growth mechanisms in cardiomyocytes. Here we present data on expression of cardiac isoforms of CaMKIIdelta, the dominant form in the myocardium, in compensatory hypertrophy of stroke-prone spontaneously hypertensive rats (SHRSP) compared to the normotensive Wistar-Kyoto (WKY) control strain. Cardiac hypertrophy in SHRSP was documented by an increased heart weight/body weight ratio (HW/BW) of 31% (p < 0.05) and a more than six-fold elevated atrial natriuretic factor (ANF) transcript level (p < 0.05). Compensatory hypertrophic growth in SHRSP produced a specific phenotype of CaMKIIdelta isoforms characterized by increased transcript levels of the embryonic/neonatal isoform delta4 (48%, p < 0.05) and the isoform delta9 (31%, p < 0.05) with no changes in delta2 and delta3. Inhibition of angiotensin converting enzyme (ACE) by cilazapril completely regressed myocardial hypertrophy, normalized ANF transcript levels, and restored the normal phenotype of CaMKIIdelta by reducing transcripts for delta4 and delta9 to levels present in WKY controls. Our data suggest the importance of specific changes in the CaMKII isoform composition for growth processes in the myocardium.

Topics: Angiotensin-Converting Enzyme Inhibitors; Animals; Atrial Natriuretic Factor; Body Weight; Calcium-Calmodulin-Dependent Protein Kinase Type 2; Calcium-Calmodulin-Dependent Protein Kinases; Cardiomegaly; Cilazapril; Genetic Predisposition to Disease; In Vitro Techniques; Isoenzymes; Male; Myocardium; Organ Size; Phenotype; Rats; Rats, Inbred SHR; Rats, Inbred WKY; Reverse Transcriptase Polymerase Chain Reaction; Stroke; Transcription, Genetic

The atrial natriuretic peptide (ANP) gene was, though inconclusive, implied to be etiologically related to stroke in rats and recently in humans. The present study tested the candidacy of ANP for stroke susceptibility by a combination of molecular genetic approaches. First, we undertook an association study using a reported ANP variant, G664A, in two case-control panels independently collected, which involved 970 Japanese subjects. Second, we compared the rat ANP gene sequences and neighboring marker alleles among stroke-prone SHR (SHRSP), normal SHR and WKY of an original inbred colony and we also compared brain ANP expression between SHRSP and normal SHR. In humans, we found no significant association between the 664A variant and stroke in the studied population. In rats, 21 polymorphic sites were identified by direct sequencing of 2170-bp ANP fragments, from which two distinct alleles, SHRSP- and WKY-types, were inferred. From a genealogical point of view, our data indicated that an SHRSP-type allele could not play a determinant role in stroke-proneness. Overall results did not support the disease relevance of ANP, disagreeing with previous reports. Thus, considerable caution should be taken when one attempts to transfer findings in the animal model to humans.

Topics: Aged; Alleles; Animals; Atrial Natriuretic Factor; Case-Control Studies; Female; Gene Expression; Genetic Predisposition to Disease; Humans; Male; Middle Aged; Polymorphism, Single Nucleotide; Rats; Rats, Inbred SHR; Rats, Inbred WKY; Stroke

Eprosartan is a selective angiotensin II type I receptor antagonist approved for the treatment of hypertension. In the present studies, eprosartan's ability to provide end-organ protection was evaluated in a model of cardiomyopathy and renal failure in stroke-prone rats (SP).. SP were fed a high fat (24.5% in food) and high salt (1% in water) diet (SFD). Eprosartan (60 mg/kg/day) or vehicle (saline control) (n = 25/group) was administered by intraperitoneally-implanted minipumps to these SP on the SFD for 12 weeks. Normal diet fed SP and WKY rats (n = 25/group) were also included for comparison (i.e. served as normal controls). Mortality, hemodynamics, and both renal and cardiac function and histopathology were monitored in all treatment groups.. Eprosartan decreased the severely elevated arterial pressure (-12%; P < 0.05) produced by SFD but did not affect heart rate. Vehicle-treated SP-SFD control rats exhibited significant weight loss (-13%; P < 0.05) and marked mortality (50% by week 6 and 95% by week 9; P < 0.01). Eprosartan-treated SP-SFD rats maintained normal weight, and exhibited zero mortality at week 12 and beyond. Eprosartan prevented the increased urinary protein excretion (P < 0.05) that was observed in vehicle-treated SP-SFD rats. Echocardiographic (i.e. 2-D guided M-mode) evaluation indicated that SP-SFD vehicle control rats exhibited increased septal (+22.2%) and posterior left ventricular wall (+30.0%) thickness, and decreased left ventricular chamber diameter (-15.9%), chamber volume (-32.7%), stroke volume (-48.7%) and ejection fraction (-22.3%), and a remarkable decrease in cardiac output (-59.3%) compared to controls (all P < 0.05). These same parameters in eprosartan-treated SP-SFD rats were normal and differed markedly and consistently from vehicle-treated SP-SFD rats (i.e. treatment prevented pathology; all P < 0.05). Cardiac-gated MRI data confirmed the ability of eprosartan to prevent cardiac pathology/remodeling (P < 0.05). Histopathological analysis of hearts and kidneys indicated that eprosartan treatment significantly reduced end-organ damage (P < 0.01) and provided corroborative evidence that eprosartan reduced remodeling of these organs. Vehicle-treated SP-SFD rats exhibited a 40% increase in the plasma level of pro-atrial natiuretic factor that was reduced to normal by eprosartan (P < 0.05).. These data demonstrate that eprosartan, at a clinically relevant dose, provides significant end-organ protection in the severely hypertensive stroke-prone rat. It preserves cardiac and renal structural integrity, reduces cardiac hypertrophy and indices of heart failure, maintains normal function of the heart and kidneys, and eliminates premature mortality due to hypertension-induced end-organ failure.

Topics: Acrylates; Animals; Antihypertensive Agents; Atrial Natriuretic Factor; Blood Pressure; Body Weight; Cardiomegaly; Heart Rate; Hypertension; Imidazoles; Kidney; Magnetic Resonance Imaging; Male; Myocardium; Natriuresis; Organ Size; Peptide Fragments; Protein Precursors; Proteinuria; Rats; Rats, Inbred SHR; Stroke; Survival Rate; Thiophenes; Ventricular Remodeling

The atrial natriuretic peptide (ANP) gene may underlie stroke susceptibility and sensitivity to cerebral ischemia in an animal model of stroke. The authors investigate its role in humans by genotyping a polymorphism (G664A) in 436 patients with ischemic cerebrovascular disease and 295 community control subjects. The frequency of this variant was similar in both groups and across the different stroke subtypes. The ANP gene G664A polymorphism is therefore unlikely to be an important risk factor for ischemic stroke in this population.

Topics: Aged; Atrial Natriuretic Factor; Brain Ischemia; Female; Genetic Predisposition to Disease; Genotype; Humans; Male; Middle Aged; Polymorphism, Single Nucleotide; Risk Factors; Stroke

Cerebrovascular accidents are the third leading cause of death after myocardial infarction and cancer in all Western societies. A more complete understanding of the pathogenetic determinants of stroke is required in order to achieve a better prevention and treatment of this common disease. Recently, based on convincing epidemiological and experimental evidence, the concept of stroke as a complex, multifactorial, polygenic disease has been well assessed. Thus, together with known modifiable determinants, such as smoking, obesity, hypertension, cardiac diseases and diabetes, specific hereditary factors for stroke are now taken into account when analysing the pathogenesis of cerebrovascular accidents. In particular, there have recently been important findings related to the genetic basis of stroke in suitable animal models and in humans, thus representing the promise of a more thorough understanding of the pathogenesis of stroke in the future and of a more specific preventive and therapeutic approach to this common pathological condition.

Topics: Animals; Atrial Natriuretic Factor; Genetic Predisposition to Disease; Humans; Natriuretic Peptide, Brain; Nerve Tissue Proteins; Quantitative Trait, Heritable; Rats; Stroke

The combination therapy with ACE inhibitors, angiotensin II type 1 (AT(1)) receptor antagonists, or calcium channel antagonists may exert more beneficial effects on cardiovascular diseases than monotherapy. Perindopril, candesartan cilexetil, or amlodipine alone or the combination of low doses of each agent was administered orally to stroke-prone spontaneously hypertensive rats (SHRSP) for 4 weeks to compare the hypotensive or cardiovascular effects. Although perindopril (2 mg/kg), candesartan cilexetil (2 mg/kg), or amlodipine (3 mg/kg) alone caused comparable hypotensive effects in SHRSP, monotherapy with perindopril or candesartan decreased left ventricular (LV) weight; mRNA levels for atrial natriuretic factor, skeletal alpha-actin, and collagen types I and III; and aortic weight and platelet-derived growth factor-beta receptor tyrosine phosphorylation to a greater extent than monotherapy with amlodipine. Although monotherapy with a low dose (0.2 mg/kg) of perindopril or candesartan cilexetil did not significantly reduce the LV mRNA levels and aortic platelet-derived growth factor-beta receptor phosphorylation of the SHRSP, combination therapy at such a low dose normalized these parameters more potently than the use of amlodipine (3 mg/kg) alone. Although perindopril or candesartan cilexetil alone at 0.05 mg/kg did not decrease the blood pressure of the SHRSP, such a low dose of combination therapy decreased LV weight and atrial natriuretic factor mRNA levels of the SHRSP to a greater extent than amlodipine alone or amlodipine combined with perindopril or candesartan cilexetil. Our results provide evidence that suggests the combination of an ACE inhibitor and an AT(1) receptor antagonist may be more effective in the treatment of cardiac and vascular diseases than the combination of a calcium channel blocker with an ACE inhibitor or an AT(1) receptor antagonist or monotherapy with each agent.

Topics: Adrenergic beta-Antagonists; Amlodipine; Angiotensin Receptor Antagonists; Angiotensin-Converting Enzyme Inhibitors; Angiotensins; Animals; Antihypertensive Agents; Aorta; Atrial Natriuretic Factor; Benzimidazoles; Biphenyl Compounds; Blood Pressure; Bradykinin; Calcium; Calcium Channel Blockers; Drug Therapy, Combination; ErbB Receptors; Gene Expression; Heart Ventricles; Hypertension; Myocardium; Organ Size; Perindopril; Phosphorylation; Rats; Rats, Inbred SHR; Rats, Inbred WKY; Receptor, Angiotensin, Type 1; Receptor, Angiotensin, Type 2; Receptors, Angiotensin; Receptors, Platelet-Derived Growth Factor; RNA, Messenger; Stroke; Tetrazoles

Previous studies have shown that short-term high salt intake unmasks blunted plasma aldosterone suppression in stroke-prone spontaneously hypertensive rats (SHRsp). The aim of this study was to evaluate the response of aldosterone biosynthesis and production to a sustained exposure to the stroke-permissive Japanese-style diet (JD) in young stroke-prone and stroke-resistant SHRs. For this purpose, 6-week old male rats from both strains were divided into 2 dietary groups and received regular diet (SHR = 37, SHRsp = 32) or the JD and 1% saline to drink (SHR = 34, SHRsp = 30) for 4 weeks. All measurements were carried out at the end of the dietary periods. After JD, plasma aldosterone levels were significantly decreased in SHR (from 357.8 +/- 57 to 163.3 +/- 31.5 pg/ml, p < 0.05) but markedly increased in SHRsp (from 442 +/- 56.5 to 739 +/- 125.7 pg/ml, p < 0.05). Consistently, the adrenal aldosterone synthase expression was reduced by JD in SHR (p < 0.05), whereas it was even slightly raised by JD in SHRsp so that, at the end of JD, aldosterone synthase mRNA was 5-fold higher in SHRsp than in SHR. Urinary sodium excretion (mEq/24h) achieved lower levels in SHRsp, so that fractional excretion of sodium was 80.2 +/- 9% in SHR and 40.3 +/- 8% in SHRsp (p < 0.05) in balance studies performed at the end of JD. These different responses of mineralocorticoid biosynthesis and urinary sodium excretion to JD were not accounted for by different adaptations of the renin-angiotensin and atrial natriuretic peptide systems, of serum potassium levels, or of adrenal 11beta-hydroxylase expression in the two strains. Systolic blood pressure was comparable in both strains throughout the experiment. These results demonstrate enhanced aldosterone biosynthesis, associated with reduced urinary excretion of sodium in response to JD in SHRsp before the onset of stroke. This abnormality may play a role in the higher susceptibility to stroke of this model.

Topics: Aldosterone; Animals; Atrial Natriuretic Factor; Hypertension; Japan; Male; Rats; Rats, Inbred SHR; Renin; Sodium Chloride, Dietary; Stroke

Topics: Animals; Atrial Appendage; Atrial Natriuretic Factor; Disease Models, Animal; Dogs; Goats; Guinea Pigs; Heart Diseases; Hemodynamics; Humans; Hypertrophy; Sheep; Stroke; Thirst; Thrombosis

Through the genotype/phenotype cosegregation analysis of an F(2) intercross, from the crossbreeding of stroke-prone spontaneously hypertensive rats (SHRSP) and stroke-resistant spontaneously hypertensive rats (SHR), we previously identified a quantitative trait locus for stroke on rat chromosome 5 (STR2) that colocalized with the genes encoding atrial and brain natriuretic peptides (ANP and BNP) and conferred a stroke-delaying effect. To further characterize ANP and BNP as candidates for stroke, we performed additional studies. Comparative sequence analysis revealed point mutations in both the coding and regulatory regions of ANP, whereas no interstrain differences were found for BNP. In in vitro studies in COS-7 and AtT-20 cells that were performed to test the relevance of a G-->A substitution at position 1125, a Gly-->Ser transposition in the SHRSP pro-ANP peptide resulted in different posttranslational processing of the SHRSP ANP gene product that was also associated with higher cGMP production (P<0.05). Furthermore, an analysis of a 5' end mutation affecting a PEA2 regulatory binding site in the 5' untranslated regulatory sequence of SHRSP ANP demonstrated a significantly lower ANP promoter activation in endothelial cells (P<0.05 versus the SHR ANP). In addition, the expression of ANP was significantly reduced in the brain, but not in the atria, of SHRSP compared with SHR (P<0.0001). No differences were detected with regard to BNP expression. The present results reveal substantial differences in ANP, but not BNP, structure and product among SHR and SHRSP, which supports a role of ANP in the pathogenesis of stroke in the SHRSP animal model.

Topics: Animals; Atrial Natriuretic Factor; Base Sequence; Gene Expression Regulation; Genetic Predisposition to Disease; Mutation; Natriuretic Peptide, Brain; Rats; Rats, Inbred SHR; Stroke

To determine how the downregulation of atrial natriuretic peptide (ANP) gene expression, previously demonstrated to occur only in the brain of the stroke-prone spontaneously hypertensive rat (SHRsp), in contrast to the stroke-resistant SHR (SHRsr), co-segregates with stroke occurrence in SHRsp/SHRsr F2 descendants in order to study the 'protective' role towards stroke previously demonstrated in SHRsp for the quantitative trait locus STR2 that also carries the ANP gene.. Eight male SHRsp, eight male SHRsr and 16 male SHRsp/SHRsr F2-intercross animals (progeny of brother/sister mated F1 hybrids from an original cross between F0 SHRsp and SHRsr) were selected for this study. All rats were exposed to a stroke-permissive Japanese-style diet starting at the age of 6 weeks. Half of the F2 animals had early strokes; the remainder had late strokes. Blood pressure was measured before sacrifice. Analysis of brain ANP expression using an RNase protection assay was performed in all animals.. Downregulation of brain ANP in the stroke-prone phenotype was found to co-segregate with the occurrence of early strokes in the F2 rats independently of blood pressure levels.. The observed lower expression of ANP in the brains of stroke-prone rats appears to be the result of an inhibitory effect by another gene or genes. It seems unlikely that this specific trait represents a primary protective mechanism.

Topics: Animals; Atrial Natriuretic Factor; Blood Pressure; Brain; Genetic Predisposition to Disease; Hypertension; Male; Phenotype; Rats; Rats, Inbred SHR; RNA, Messenger; Stroke; Time Factors