AIMTo investigate the effect of vasonatrin peptide (VNP) on the expression of C-type natriuretic peptide receptor (NPR-C) in hypoxic rat hearts.

METHODSRats were divided randomly into three groups: control group, hypoxia group(3-28 d) and VNP (25-75 microg/kg per day) + hypoxia group. The plasma concentration of atrial natriuretic peptide (ANP) in rats was measured by the means of radioimmunoassay. Furthermore, quantitative PCR was used to examine the NPR-C mRNA level in rat hearts.

RESULTSThe plasma concentration ANP in rats was significantly higher than that of control group, and VNP (75 microg/kg per day) made it more higher. Hypoxia for 3 day of had no significant effect on the NPR-C mRNA level in rat hearts, while hypoxia for 7-28 d significantly increased the level of NPR-C mRNA in a time dependent manner. VNP (50-75 microg/kg per day) significantly reduced the NPR-C mRNA level in rat hearts in a dose dependent manner.

CONCLUSIONVNP increases the plasma concentration of ANP in hypoxic rats. Hypoxia can increase expression of NPR-C in rat hearts significantly, which can be inhibited by VNP.

Animals ; Atrial Natriuretic Factor ; blood ; pharmacology ; Hypoxia ; metabolism ; Male ; Natriuretic Peptide, C-Type ; metabolism ; Natriuretic Peptides ; metabolism ; Rats ; Rats, Sprague-Dawley ; Receptors, Atrial Natriuretic Factor ; metabolism

OBJECTIVETo identify and characterize the polypeptides specifically binding to human B type natriuretic peptide (BNP) screened from 12TM phage display peptide library.

METHODSThe BNP-binding peptides were screened from 12TM phage display peptide library and identified by ELISA.

RESULTSAfter 4 rounds of screening, 10 of the 16 phage clones were identified as the positive clones which could bind to BNP. Five amino acid sequences were obtained in the 10 positive clones. Dose-dependent ELISA results demonstrated that the screened polypeptides could specifically bind to BNP.

CONCLUSIONThese screened polypeptides can bind specifically to BNP, which provides a basis for further research on expression and purification of anti-BNP polypeptides and the development of the detection kit of BNP.

Humans ; Natriuretic Peptide, Brain ; metabolism ; Peptide Library ; Peptides ; analysis ; isolation & purification ; metabolism ; Protein Binding

Natriuretic peptides comprise a family of three structurally related peptides; atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), and C-type natriuretic peptide (CNP). The present study was performed to investigate the effect of ANP on the proliferation and activity of ROS17/2.8 and HOS cells which are well-characterized osteoblastic cell lines. ANP dose-dependently decreased the number of ROS17/2.8 and HOS cells after 48-hour treatment. ANP generally increased the alkaline phosphatase activity of ROS17/2.8 and HOS cells after 48 hr treatment, regardless of the fact that basal activity of alkaline phosphatase was much lower in HOS cells compared to that of ROS17/1.8 cells. ANP increased the NBT reduction by ROS17/2.8 and HOS cells. ANP showed the variable but no significant effect on the nitric oxide production by ROS17/2.8 and HOS cells. ROS17/2.8 and HOS cells produced and secreted gelatinase into culture medium, and this enzyme was thought to be the gelatinase A type with the molecular weight determination. The gelatinase activity produced by ROS17/2.8 cells was increased by the treatment of ANP. However, the enzyme activity was not affected by ANP treatment in the HOS cell culture. In summary, ANP decreased the proliferation and increased the alkaline phosphatase activity and NBT reduction of osteoblasts. These results indicate that ANP is one of the important regulators of bone metabolism.
Alkaline Phosphatase ; Atrial Natriuretic Factor ; Cell Culture Techniques ; Cell Line ; Gelatinases ; Humans ; Matrix Metalloproteinase 2 ; Metabolism ; Molecular Weight ; Natriuretic Peptide, Brain ; Natriuretic Peptide, C-Type ; Natriuretic Peptides ; Nitric Oxide ; Osteoblasts* ; Peptides

Natriuretic peptides (NPs) have been found to be useful markers in differentiating acute dyspneic patients presenting to the emergency department (ED) and emerged as potent prognostic markers for patients with congestive heart failure (CHF). The best-established and widely used clinical application of BNP and NT-proBNP testing is for the emergent diagnosis of CHF in patients presenting with acute dyspnea. Nevertheless, elevated NPs levels can be found in many circumstances involving left ventricular (LV) dysfunction or hypertrophy; right ventricular (RV) dysfunction secondary to pulmonary diseases; cardiac inflammatory or infectious diseases; endocrinology diseases and high output status without decreased LV ejection fraction. Even in the absence of significant clinical evidence of volume overload or LV dysfunction, markedly elevated NP levels can be found in patients with multiple comorbidities with a certain degree of prognostic value. Potential clinical applications of NPs are expanded accompanied by emerging reports regarding screening the presence of secondary cardiac dysfunction; monitoring the therapeutic responses, risk stratifications and providing prognostic values in many settings. Clinicians need to have expanded knowledge regarding the interpretation of elevated NPs levels and potential clinical applications of NPs. Clinicians should recognize that currently the only reasonable application for routine practice is limited to differentiation of acute dyspnea, rule-out-diagnostic-tests, monitoring of therapeutic responses and prognosis of acute or decompensated CHF. The rationales as well the potential applications of NPs in these settings are discussed in this review article.
Acute Coronary Syndrome/metabolism ; Arrhythmias, Cardiac/metabolism ; Heart Failure/*metabolism ; Humans ; Hypertension, Pulmonary/metabolism ; Natriuretic Peptides/*metabolism ; Sepsis/metabolism

OBJECTIVETo investigate the expression of guanylin in colorectal cancer.

METHODSThe expression of guanylin was examined by RT-PCR and semiquantitative analysis in 20 cases of colorectal cancer, and its relationship with clinical characteristics was analyzed.

RESULTSThe positive expression of guanylin in normal tissue (80%, 16/20) was significantly higher than that in tumor tissue (35%, 7/20) (P<0.01). The same result was found in the semiquantitative analysis of 14 cases with differential expression. Differential expression of guanylin in colorectal cancer was associate with TNM stage (P<0.05), not with sex, Borrmann type and degree of differentiation (all P>0.05).

CONCLUSIONThere is differential expression of guanylin in colorectal cancer, and this kind of differential expression is associated with tumor TNM stage.

Colorectal Neoplasms ; metabolism ; pathology ; Female ; Gastrointestinal Hormones ; metabolism ; Humans ; Male ; Middle Aged ; Natriuretic Peptides ; metabolism ; Neoplasm Staging

3-Iodobenzylguanidine ; Adult ; Aged ; Echocardiography ; Female ; Heart Failure ; diagnosis ; metabolism ; pathology ; Humans ; Male ; Middle Aged ; Myocardial Perfusion Imaging ; methods ; Natriuretic Peptides ; metabolism ; Prognosis ; Prospective Studies

In order to improve the expression of recombinant human atrial natriuretic peptide (ANP), a new plasmid (pET28a(+)/ANP₃) containing 3 tandem ANP genes with lysine codon as the interval linker, was constructed. Target gene was transformed into Escherichia coli BL21 (DE3) and induced by IPTG, about 60% of the total-cell-protein was the target protein, His₆-ANP₃. After denaturation and refolding, it was digested by Endoproteinase Lys-C and Carboxypeptidase B (CPB) and then purified by a series of purification processes, about 16 mg purified ANP monomer could be obtained from one liter bacteria broth of shaking culture. Ultimately, the purity of protein was above 90% determined by UPLC and Tricine SDS-PAGE, its molecular weight was 3 080 Da according to LC-MS identification and it was proved to be equivalent to the reference product by ELISA. The use of tandem gene expression can provide a new possible model for the expression of other peptide drugs.
Atrial Natriuretic Factor ; biosynthesis ; Electrophoresis, Polyacrylamide Gel ; Escherichia coli ; metabolism ; Gene Expression ; Humans ; Metalloendopeptidases ; Peptides ; Plasmids ; genetics ; Recombinant Fusion Proteins ; biosynthesis

AMP-activated protein kinase (AMPK) is a key regulator of energy metabolism. Previous studies have shown that activation of AMPK results in suppression of cardiac myocyte hypertrophy via inhibition of the p70S6 kinase (p70S6K) and eukaryotic elongation factor-2 (eEF2) signaling pathways. Epigallocatechin-3-gallate (EGCG), the major polyphenol found in green tea, possesses multiple protective effects on the cardiovascular system including cardiac hypertrophy. However, the molecular mechanisms has not been well investigated. In this study, we found that EGCG could significantly reduce natriuretic peptides type A (Nppa), brain natriuretic polypeptide (BNP) mRNA expression and decrease cell surface area in H9C2 cardiomyocytes stimulated with phenylephrine (PE). Moreover, we showed that AMPK is activated in H9C2 cardiomyocytes by EGCG, and AMPK-dependent pathway participates in the inhibitory effects of EGCG on cardiac hypertrophy. Taken together, our findings provide the first evidence that the effect of EGCG against cardiac hypertrophy may be attributed to its activation on AMPK-dependent signaling pathway, suggesting the therapeutic potential of EGCG on the prevention of cardiac remodeling in patients with pressure overload hypertrophy.
AMP-Activated Protein Kinases ; Brain ; Cardiomegaly ; Cardiovascular System ; Energy Metabolism ; Humans ; Hypertrophy* ; Myocytes, Cardiac* ; Natriuretic Peptides ; Phenylephrine ; Phosphotransferases ; RNA, Messenger ; Tea

BACKGROUNDThe over increase of sympathetic drive in chronic heart failure (CHF) is with main responsibility for the deterioration and mortality of the disease. Myocardial (123)I-metaiodobenzylganidine (MIBG) scintigraphy is a non-invasive convenient method to assess sympathetic dysfunction in patients with CHF. The aim of the study was to detect if sympathetic antidrive analysed through myocardial MIBG scintigraphy plays a crucial role in long-term prognosis in CHF.

METHODSSixty-four enrolled patients underwent myocardial MIBG scintigraphy, and their plasma concentration of brain natriuretic peptide (BNP), myocardial contractile reserve (MCR), rest left ventricular ejection fraction (rest LVEF) and New York Heart Association (NYHA) function class were assessed. They were separated into groups according to median of above parameters. Endpoint was cardiac death and it was recorded in each group during average 54 months' follow-up.

RESULTSAt the end of follow-up, group with lower ratio of heart/mediastinum (H/M) had more death events (P = 0.001), and its BNP level was higher and MCR level was lower (P = 0.003 and 0.001, respectively); but its rest LVEF and NYHA function class were not significantly different. H/M, MCR and BNP correlated closely with death (P = 0.000, 0.000 and 0.001, respectively). Among the three indicators the death risk ratio (RR) of H/M was 4.66, more than MCR and BNP (1.88 and 2.56, respectively). However, rest LVEF and NYHA function class did not correlate with death (P = 0.652 and 0.384, respectively). The group with lower H/M and MCR, higher BNP had much more death than that with higher H/M and MCR, lower BNP, the RR being 12.8.

CONCLUSIONSMyocardial MIBG scintigraphy is a long-term prognostic marker in CHF. BNP, MCR are also excellent predictors of long-term prognosis in CHF, but not stronger than myocardial MIBG scintigraphy. If the three indicators were joined together, the prediction would become most powerful. Rest LVEF and NYHA have no significance in long-term prediction of CHF.

3-Iodobenzylguanidine ; Adult ; Aged ; Aprotinin ; chemistry ; Brain ; metabolism ; Echocardiography ; Edetic Acid ; chemistry ; Female ; Heart Failure ; metabolism ; pathology ; Humans ; Male ; Middle Aged ; Myocardial Perfusion Imaging ; methods ; Natriuretic Peptides ; metabolism ; Prognosis ; Prospective Studies

The present study was aimed at investigating the regulation of atrial natriuretic peptide (ANP) system in association with either enhanced or attenuated activity of the renin-angiotensin system (RAS). The cardiac tissue mRNA and peptide levels of ANP were measured in rats with two-kidney, one clip (2K1C) or deoxycorticosterone acetate (DOCA)-salt hypertension. Plasma renin concentration was increased in 2K1C hypertension along with increases of renin mRNA and protein contents in the clipped kidney. On the contrary, it was suppressed in DOCA-salt hypertension along with decreases of renin mRNA and protein contents in the remaining kidney. The plasma ANP concentration was similarly increased in both models of hypertension. The cardiac tissue ANP contents were not significantly changed, but the tissue ANP mRNA levels were upregulated in the hypertrophied heart in these two models of hypertension. It is suggested that the cardiac ANP system is transcriptionally enhanced by cardiac hypertrophy associated with hypertension, independent of the systemic RAS.
Animal ; Atrial Natriuretic Factor/metabolism* ; Desoxycorticosterone ; Gene Expression Regulation ; Hypertension/metabolism* ; Hypertension/chemically induced ; Male ; Myocardium/pathology ; Organ Weight ; Peptides ; RNA, Messenger/analysis ; Rats ; Rats, Sprague-Dawley ; Renin/genetics* ; Renin/blood* ; Renin-Angiotensin System/physiology