脑钠肽临床应用进展

脑钠肽(brain natriuretic peptide,BNP)是近年倍受关注的心血管生物标记物,BNP是一种主要由心脏分泌的肽类激素,在心脏维持其正常结构和功能的中起着重要的作用,它具有利钠、利尿、扩血管、降压、拮抗RAAS系统、抑制交感神经兴奋等作用.它已超过原来仅作为心衰的诊断检测指标范畴.研究表明BNP与呼吸困难的鉴别诊断、心肌梗死、高血压、心房颤动、心肌病、肺栓塞等关系密切,现就BNP的临床研究进展作一综述.     

Atrial Natriuretic Peptide (ANP) Regulates the Biological Activity of EGF/EGFR System in Adult Retinal Pigment Epithelial Cell

International Journal of Peptide Research and Therapeutics - Atrial natriuretic peptide (ANP) is a type of peptide hormone secreted by atrial cells, which has many important biological functions...     

重组人脑利钠肽的临床应用进展

近年来,随着心力衰竭、肺动脉高压的病理生理及分子机制的深入研究,使上述疾病在临床药物治疗方面有了很大的进步,其中人脑利钠肽(BNP)作为体内唯一天然的肾素-血管紧张素-醛固酮拮抗剂在诊断及治疗心力衰竭等方面均引起了广泛关注,但由于其在心衰状态下降解快且生物活性明显减弱而限制了临床应用。因此,在心力衰竭治疗上补充外源性BNP成为了又一研究热点。重组人脑利钠肽(rhBNP)是一种人工合成的内源性激素,具有扩张血管、排钠利尿、降低心脏前后负荷、抑制肾素-血管紧张素-醛固酮系统和交感神经系统等作用,能够有效的改善充血性心力衰竭患者的血流动力学障碍。新近研究表明,rhBNP在治疗心血管疾病方面疗效显著,本文将就其在临床中的应用予以综述。     

Immunohistochemistry of Atrial Natriuretic Peptide in Brain Infarction

Atrial natriuretic peptide (ANP) was originally isolated from cardiac atria, and has potent natriuretic, diuretic, and vasorelaxant properties. It has been localized in neurons and astrocytes in the cerebral cortex and the white matter. We hypothesize that glial ANP may contribute to the regulation of cerebral blood flow in brain infarction. In order to elucidate this possible role, the immunohistochemistry of ANP was studied in cases of brain infarction and in other cases of brain trauma for comparison. A statistically significant increase in the number of ANP-immunoreactive glial cells (mainly astrocytes) was observed in the white matter surrounding the brain infarction compared with the intact area. No statistically significant increase in ANP-immunoreactive glial cell number was observed in the cerebral white matter from brain haemorrhage, contusion and control cases. Our results indicate that glial ANP may increase in number in brain infarction, and that it may be involved in the regulation of the cerebral blood flow in the infarcted area.     

The Role of the Circulation in Processing pro-Brain Natriuretic Peptide (proBNP) to Amino-Terminal BNP and BNP-32

Hunt, P. J., E. A. Espiner, G. M. Nicholls, A. M. Richards and T. G. Yandle. The role of the circulation in processing pro-brain natriuretic peptide (proBNP) to amino-terminal BNP and BNP-32. Peptides 18(10) 1475–1481, 1997.—Human proBNP (purified from cardiac tissue) was incubated at 37°C in whole blood, serum and plasma and the products analyzed by size exclusion high pressure liquid chromatography and radioimmunoassay (RIA). In addition to RIAs for BNP-32 and NT-proBNP(1-13), a newly developed RIA for proBNP(62-76) was also used to identify the peptides. Incubation with serum resulted in the formation of a 9 kDa and a 3 kDa peptide, consistent with the N-terminal and the C-terminal peptides of the propeptide. Minimal processing of proBNP was seen in blood or plasma, suggesting that the circulation does not play a major role in the activation of proBNP. Analysis of degradation products of human proBNP using site directed specific antisera indicates that removal of N-terminal amino acids from proBNP occurs in serum. These findings support the view that the “high molecular weight BNP-32” previously identified in human plasma comprises amino-terminal deleted forms, and is unlikely to be intact proBNP(1-108).     

In Situ and in Vitro Binding of Natriuretic Peptide Hormones in Tradescantia multiflora

Abstract: An increasing body of evidence suggests that in plants, as in vertebrates, biologically active natriuretic peptide (NP) hormones play an important role in the regulation of the osmotic and ionic balance. The evidence includes isolation and immunoaffinity purification of biologically active natriuretic peptide analogues (irPNP) from ivy that promoted stomatal opening and specifically, rapidly and transiently increased cGMP levels in root conductive tissue. In this study we demonstrate that I¹²⁵-rat atrial natriuretic peptide (rANP) binds to plasma membranes from leaf and stem tissue of Tradescantia multiflora and importantly, both unlabelled rANP and irPNP can competitively displace that binding. In addition, tissue section autoradiography reveals specific in situ binding of I¹²⁵-rANP to leaf and stem tissue. The findings are consistent with the presence of a biologically active NP system in plants and suggest that NPs signal through a dedicated receptor system.     

Structural Substrate Conditions Required for Neutral Endopeptidase-Mediated Natriuretic Peptide Degradation

Natriuretic peptides are cyclic vasoactive peptide hormones with great diagnostic and therapeutic relevance. The main catabolic pathway postulated for natriuretic peptides is the degradation by neutral endopeptidase (NEP). However, B-type natriuretic peptide has been found to be resistant to NEP. Here, we compared the degradation of various mature, truncated, and recombinant natriuretic peptides by NEP. The degradation was clearly dependent on the length of the N- or C-terminus as well as on distinct sequence differences within the essential loop structure of the natriuretic peptides. Based on these findings, we developed a model for the interaction of NEP and natriuretic peptides that enables new insights into the mode of action and prediction of substrates of NEP, a peptidase that plays a key role in crucial (patho-) physiological processes.     

A Familial Mutation Renders Atrial Natriuretic Peptide Resistant to Proteolytic Degradation

A heterozygous frameshift mutation causing a 12-amino acid extension to the C terminus of atrial natriuretic peptide (ANP) was recently genetically linked to patients with familial atrial fibrillation (Hodgson-Zingman, D. M., Karst, M. L., Zingman, L. V., Heublein, D. M., Darbar, D., Herron, K. J., Ballew, J. D., de Andrade, M., Burnett, J. C., Jr., and Olson, T. M. (2008) N. Engl. J. Med. 359, 158–165). The frameshift product (fsANP), but not wild-type ANP (wtANP), was elevated in the serum of affected patients, but the molecular basis for the elevated peptide concentrations was not determined. Here, we measured the ability of fsANP to interact with natriuretic peptide receptors and to be proteolytically degraded. fsANP and wtANP bound and activated human NPR-A and NPR-C similarly, whereas fsANP had a slightly increased efficacy for human NPR-B. Proteolytic susceptibility was addressed with novel bioassays that measure the time required for kidney membranes or purified neutral endopeptidase to abolish ANP-dependent activation of NPR-A. The half-life of fsANP was markedly greater than that of wtANP in both assays. Additional membrane proteolysis studies indicated that wtANP and fsANP are preferentially degraded by neutral endopeptidase and serine peptidases, respectively. These data indicate that the familial ANP mutation associated with atrial fibrillation has only minor effects on natriuretic peptide receptor interactions but markedly modifies peptide proteolysis.Natriuretic peptides are pleiotropic factors that regulate blood pressure, cardiac hypertrophy, and long bone growth (1). Humans express three family members, atrial natriuretic peptide (ANP),³ B-type natriuretic peptide, and C-type natriuretic peptide (CNP). Each peptide is the product of a separate gene and contains a highly conserved 17-amino acid disulfide-linked ring structure that is required for biological activity. Atrial stretch causes ANP to be released from stored granules as a result of cardiovascular stresses like congestive heart failure. Once released into the circulation, ANP binds receptors in multiple tissues to reduce the load on the heart by stimulating natriuresis, diuresis, extravasation, vasorelaxation, and inhibiting the renin-angiotensin-aldosterone system (1).Natriuretic peptides exert their effects by binding one or more of three natriuretic peptide receptors. Natriuretic peptide receptor A (NPR-A) is the endogenous receptor for ANP and BNP (2, 3). NPR-A is a transmembrane guanylyl cyclase that, upon ligand binding, synthesizes the second messenger cGMP that mediates the renal and vascular effects of ANP and BNP (4, 5). Meanwhile, natriuretic peptide receptor B (NPR-B) is the receptor for CNP (6). NPR-B is highly homologous to NPR-A and also possesses guanylyl cyclase activity. The primary ligand for NPR-B is CNP, but this receptor can also be activated by very high concentrations of ANP or BNP (6). CNP-dependent activation of NPR-B stimulates long bone growth and may also inhibit cardiac hypertrophy (7). The third natriuretic peptide receptor is natriuretic peptide receptor C (NPR-C). Unlike NPR-A and NPR-B, NPR-C does not contain a guanylyl cyclase domain (8). Instead, the primary function of NPR-C is to control local natriuretic peptide concentrations through receptor-mediated internalization and degradation. Thus, it is typically referred to as the clearance receptor (9). In addition to its role in clearing natriuretic peptides from the circulation, NPR-C has also been shown to signal in a G protein-dependent manner (10). Finally, the other mechanism for natriuretic peptide removal is proteolytic degradation. Neutral endopeptidase (EC 3.4.24.11), which is also referred to as neprilysin or NEP, has been suggested to be the primary ANP-degrading enzyme in tissues associated with ANP clearance (11–13). Furthermore, inhibitors of NEP have been shown to increase circulating concentrations of ANP in rats (14).In a recent New England Journal of Medicine article, Hodgson-Zingman et al. (15) investigated the genetic basis for early onset atrial fibrillation in a family with white European ancestry. Using linkage analysis they found that all affected family members contained a single allele with a frameshift mutation in the coding portion of the ANP gene. The mutation causes a two-base pair deletion in exon 3 that eliminates the original stop codon and causes 12 new amino acids to be appended to the C terminus of the mature peptide. Thus, the peptide resulting from the frameshift mutation (fsANP) consists of 40 amino acids, whereas the wild-type peptide (wtANP) consists of 28 amino acids (Fig. 1). Importantly, the plasma levels of fsANP were shown to be 5–10-fold higher than the plasma concentrations of wtANP in affected individuals.Open in a separate windowFIGURE 1.Cartoon schematic of the primary amino acid structure of human atrial natriuretic peptide (wtANP) and the primary amino acid structure of the ANP frameshift mutation (fsANP). The 12-amino acid extension of fsANP is shaded in light gray. The dark gray shading indicates residues conserved in all natriuretic peptides. The black bars indicate disulfide bonds.Although Hodgson-Zingman et al. elegantly identified the ANP mutation associated with patients with early onset atrial fibrillation, they did not determine how this mutation affects the ability of ANP to interact with its known biological partners or why this mutation leads to elevated peptide concentrations. Theoretically, modulated binding to NPR-A, NPR-B, or NPR-C or altered proteolytic processing of ANP could lead to the observed disease. In this report, we identified subtle differences in the ability of fsANP and wtANP to interact with natriuretic peptide receptors but major differences in the proteolytic degradation of these peptides.     

Isolation and Characterization of a Natriuretic Peptide from Crotalus oreganus abyssus (Grand Canyon Rattlesnake) and its Effects on Systemic Blood Pressure and Nitrite Levels

Studies on the therapeutic potential of venom peptides have significantly advanced the development of new peptide drugs. A good example is captopril, a synthetic peptide drug, which acts as an anti-hypertensive and potentiating bradykinin, inhibiting the angiotensin-converting enzyme, whose precursor was isolated from the venom of Bothrops jararacussu. The natriuretic peptide (NPs) family comprises three members, ANP (atrial natriuretic peptide), BNP (B-type natriuretic peptide) and CNP (C-type natriuretic peptide), and has an important role in blood pressure regulation and electrolyte homeostasis. In this study, we describe, for the first time, the isolation and characterization of a novel natriuretic-like peptide (Coa_NP), isolated from Crotalus Oreganus abyssus venom. The peptide has 32 amino acids and its complete sequence is SKRLSNGCFGLKLDRIGAMSGLGCWRLINESK. The Coa_NP has an average molecular mass of 3510.98 Da and its amino acid sequence presents the loop region that is characteristic of natriuretic peptides (17 amino acids, NP domain consensus; CFGXXXDRIXXXSGLGC). Coa_NP is a natriuretic peptide of the ANP/BNP-like family, since the carboxy terminal region of CNP has its own NP domain. The functional experiments showed that Coa_NP produced biological effects similar to those of the other natriuretic peptides: (1) a dose-dependent decrease in mean arterial pressure; (2) significant increases in plasma nitrite levels, and (3) vasorelaxation in thoracic aortic rings that were pre-contracted with phenylephrine. The structural and biological aspects confirm Coa_NP as a natriuretic peptide isolated from snake venom, thus expanding the diversification of venom components.     

Effect of Atrial Natriuretic Peptide on Sodium-Glucose Cotransport in the Rat Small Intestine

GonzÁLez Bosc, L. V., P. A. Elustondo, M. C. Ortiz and N. A. Vidal. Effect of atrial natriuretic peptide on sodium-glucose cotransport in the rat small intestine. Peptides 18(10) 1491–1495, 1997.—Atrial natriuretic peptide (ANP) decreases sodium absorption in small intestine of rats in vitro under sodium concentration-gradient conditions (SCG) and this effect may be mediated by the inhibition of the sodium/glucose cotransporter (SGLT). In order to assess this hypothesis, the effects of ANP, phloridzine (Phlz) and methylene blue (MB), added alone or together, using a voltage clamp technique in Ussing’s chamber with SCG were studied. ANP and Phlz significantly decreased potential difference and short circuit current. Effects of Phlz and ANP were not additive. The addition of MB alone did not affect ion transport, whereas it abolished ANP effects. These data suggest that ANP blocks the SGLT through mechanisms mediated by cGMP and/or NO.     

脑钠肽在慢性心功能不全诊治的临床观察

目的：评价脑钠肽在慢性心功能不全过程中的诊治效果,探讨其临床适用性。方法：选择从2012年3月至2013年3月于我院就诊的82例心功能不全患者作为实验组,另选择同期的80例健康体检者作为对照组,分析实验组和对照组人员的脑钠肽的浓度,以及实验组患者经过治疗后的脑钠肽浓度变化情况,所有人员同时给予超声心动并观察实验组血浆脑钠肽浓度与左室射血分数及心功能分级之间的关系。结果：实验组患者的血浆脑钠肽浓度明显高于对照组人员,差异有统计学意义（P〈0．05）;实验组患者治疗前后血浆脑钠肽浓度有明显改变,差异也有统计学意义（P〈0．05）;心功能和左室射血分数不同分级之间的血浆脑钠肽浓度也不同,各级差异有明显统计学意义（P〈0．05）;脑钠肽浓度的不同参考值测定的灵敏度和特异性也不同。结论：脑钠肽在慢性心功能不全的诊治过程中有重要价值,为临床心功能的判断可以提供较为敏感的指示,适合临床长期推广应用。     

A Novel Bioassay for the Activity Determination of Therapeutic Human Brain Natriuretic Peptide (BNP)

Background

Recombinant human brain natriuretic peptide (rhBNP) is an important peptide-based therapeutic drug indicated for the treatment of acute heart failure. Accurate determination of the potency of therapeutic rhBNP is crucial for the safety and efficacy of the drug. The current bioassay involves use of rabbit aortic strips, with experiments being complicated and time-consuming and markedly variable in results. Animal-less methods with better precision and accuracy should be explored. We have therefore developed an alternative cell-based assay, which relies on the ability of BNP to induce cGMP production in HEK293 cells expressing BNP receptor guanylyl cyclase-A.

Methodology/Principal Findings

An alternative assay based on the measurement of BNP-induced cGMP production was developed. Specifically, the bioassay employs cells engineered to express BNP receptor guanylyl cyclase-A (GCA). Upon rhBNP stimulation, the levels of the second messager cGMP in these cells drastically increased and subsequently secreted into culture supernatants. The quantity of cGMP, which corresponds to the rhBNP activity, was determined using a competitive ELISA developed by us. Compared with the traditional assay, the novel cell-based assay demonstrated better reproducibility and precision.

Conclusion/Significance

The optimized cell-based assay is much simpler, more rapid and precise compared with the traditional assay using animal tissues. To our knowledge, this is the first report on a novel and viable alternative assay for rhBNP potency analysis.     

心钠肽在小鼠卵巢中的表达及其对受精的影响

目的探讨心钠肽（ANP）在小鼠卵泡发育过程中的表达定位以及其对体外受精的影响。方法应用免疫组织化学对小鼠卵巢切片进行染色,检测ANP在卵泡不同发育阶段的表达情况。利用ANP受体A的拮抗剂anantin检测ANP在小鼠体外受精中的作用。结果在卵泡生长和分化期,ANP广泛地存在于间质细胞、内膜细胞、颗粒细胞、卵丘细胞、卵母细胞以及黄体细胞的胞质中,特别是在排卵前卵泡中的卵丘细胞上其表达最强;经ANP受体A的拮抗剂anantin孵育后的小鼠精子,其体外受精的卵裂率与对照组相比显著下降（58.7±4.3 vs.92.3±2.1,P〈0.01）,但是对胚胎后来的发育没有影响。结论卵丘细胞中表达的ANP可能通过受体A参与了小鼠的受精过程。     

Atrial Natriuretic Peptide Regulation of Vertebrate Intestinal Ion Transport

Atrial natriuretic peptide (ANP), in spite of its name, is synthesizedand secreted in vertebrates by both the atria and the ventriclesand also a number of extracardiac tissues. Likewise, the listof putative targets of ANP is large and includes, in additionto the kidney and vascular smooth muscle, the ion- and water-transportingintestine. Immunohistochemical staining of the intestine ofthe euryhaline marine goby Gillichthys mirabilis demonstratesthe presence of ANP-ergic neurons in the submucosa suggestingparacrine delivery to intestinal epithelial and smooth musclecells. ANP inhibits ion absorption across the goby intestine,supportingan osmoregulatory role for ANP.     

脑钠肽与急性心肌梗死的研究进展

脑钠肽是心肌细胞分泌的一种循环激素。左心室的牵张和心室壁张力的增加对BNP的合成和分泌起主要调节作用;心肌缺血也是BNP释放的重要触发因素之一。对BNP水平进行分级能够很好的对急性心肌梗死进行危险分层,对诊断、预后的评估有重要意义。本文就脑钠肽的特性及与心肌梗死的关系做一综述。     

C-Type Natriuretic Peptide Is a Potent Stimulator of Cyclic GMP Production in Cultured Mouse Astrocytes

The effect of C-type natriuretic peptide (CNP), a novel member of the natriuretic peptide family, on cyclic GMP (cGMP) generation was studied in primary cultures of mouse astrocytes. CNP stimulated cGMP production by mouse astrocytes in a dose-dependent fashion, with an EC50 of 32 nM and a maximal stimulatory concentration of greater than 1 microM, which induced a rise of cGMP level from a baseline of 1.0 +/- 0.1 pmol/mg of protein to 196.2 +/- 22.0 pmol/mg of protein. Compared with our previously reported atrial and brain natriuretic peptide-induced cGMP responses, CNP had a lower EC50 and was 10-20 times more efficacious in its maximal effect on cGMP stimulation. These data lend support to the concept of a significant role of CNP in neuromodulation/neurotransmission.     

Selective Chronic Sodium or Chloride Depletion Specifically Modulates Subfornical Organ Atrial Natriuretic Peptide Receptor Number in Young Rats

1. We studied the effects of selective chronic sodium depletion of chloride depletion on atrial natriuretic peptide receptor number in the subfornical organ and paraventricular nucleus of young rats.2. Sodium or chloride depletion decreased plasma levels of atrial natriuretic peptide, increased plasma renin activity, and induced extracellular fluid volume contraction. Chloride depletion induced more significant changes in extracellular fluid volume contraction than sodium depletion.3. In the subfornical organ, atrial natriuretic peptide receptor number significantly decreased (30%) after sodium depletion, while chloride depletion induced a smaller, not statistically significant decrease. Conversely, atrial natriuretic peptide receptors located in the paraventricular nucleus of young rats were not significantly affected by sodium or chloride depletion.4. Water deprivation reversed the decrease in atrial natriuretic peptide receptors produced by sodium depletion. Water-deprived sodium-depleted rats actually had higher numbers of atrial natriuretic peptide receptors in the subfornical organ than control rats. These changes were associated with severe extracellular fluid volume contraction and up regulation of brain vasopressin mRNA steady-state levels. Thus, the direction of change in the number of subfornical organ atrial natriuretic peptide receptors was dependent on the degree of extracellular fluid volume contraction.5. Our results suggest that atrial natriuretic peptide receptors located in the subfornical organ, and not in the paraventricular nucleus, are selectively regulated by sodium depletion and extracellular fluid volume contraction.     

Olefinic Peptide Nucleic Acid (OPA)

Abstract

The olefinic peptide nucleic acid analogues (OPA) monomers containing the bases thymine and adenine were synthesised in 11 steps. Fully modified oligomers containing these units were prepared and their pairing properties assessed by means of UV-melting experiments.