Usefulness of carperitide for the treatment of refractory heart failure due to severe acute myocardial infarction

Senescence-Associated Secretory Phenotype of Cardiovascular System Cells and Inflammaging: Perspectives of Peptide Regulation

A senescence-associated secretory phenotype (SASP) and a mild inflammatory response characteristic of senescent cells (inflammaging) form the conditions for the development of cardiovascular diseases: atherosclerosis, coronary heart disease, and myocardial infarction. The purpose of the review is to analyze the pool of signaling molecules that form SASP and inflammaging in cells of the cardiovascular system and to search for targets for the action of vasoprotective peptides. The SASP of cells of the cardiovascular system is characterized by a change in the synthesis of anti-proliferative proteins (p16, p19, p21, p38, p53), cytokines characteristic of inflammaging (IL-1α,β, IL-4, IL-6, IL-8, IL-18, TNFα, TGFβ1, NF-κB, MCP), matrix metalloproteinases, adhesion molecules, and sirtuins. It has been established that peptides are physiological regulators of body functions. Vasoprotective polypeptides (liraglutide, atrial natriuretic peptide, mimetics of relaxin, Ucn1, and adropin), KED tripeptide, and AEDR tetrapeptide regulate the synthesis of molecules involved in inflammaging and SASP-forming cells of the cardiovascular system. This indicates the prospects for the development of drugs based on peptides for the treatment of age-associated cardiovascular pathology.

Effects of carperitide on the long-term prognosis of patients with acute decompensated chronic heart failure: the PROTECT multicenter randomized controlled study

BACKGROUND

Carperitide is used to treat acute decompensated heart failure (ADHF), but its effects on long-term prognosis have not been studied.

METHODS AND RESULTS

A multicenter randomized controlled study of 49 patients with ADHF was performed to clarify the drug's effects on long-term prognosis. Low-dose carperitide (0.01-0.05 microg x kg(-1 ) x min(-1)) was infused for 72 h as the initial treatment (n=26), whereas in the control group (n=23), standard medical treatment other than carperitide was given without limitation. Anti-aldosterone drugs were prohibited in both groups. During carperitide infusion, significant increases of the atrial natriuretic peptide and cyclic GMP levels and a significant decrease in the heart-type fatty acid-binding protein/serum creatinine ratio were observed, suggesting inhibition of myocyte cell membrane damage. On the other hand, no significant differences in the plasma brain natriuretic peptide, troponin T, and creatinine levels were noted in either group. During 18-month follow-up, significant reductions of death and rehospitalization occurred in the carperitide vs control group (11.5% vs 34.8%; p=0.0359). Cox regression analysis revealed that randomization to carperitide (p=0.020), pretreatment systolic blood pressure >or=140 mmHg (p=0.043), and beta-blocker therapy (p=0.016) were independent predictors for freedom from cardiac events.

CONCLUSIONS

Acute-phase low-dose carperitide infusion improved the long-term prognosis of patients with ADHF.

Effect of atrial natriuretic peptide on left ventricular remodelling in patients with acute myocardial infarction

Atrial natriuretic peptide (ANP) is a member of the natriuretic peptide family that exerts various biological effects via acting on the receptor-guanylyl cyclase system, increasing the content of intracellular cyclic guanosine monophosphate (cGMP). ANP was first identified as a diuretic/natriuretic and vasodilating hormone, but subsequent studies revealed that ANP has a very important function in the inhibition of the renin-angiotensin-aldosterone system (RAAS), endothelin synthesis, and sympathetic nerve activity. Evidence is also accumulating from recent work that ANP exerts its cardioprotective functions not only as a circulating hormone but also as a local autocrine and/or paracrine factor. ANP inhibits apoptosis and hypertrophy of cardiac myocytes, and inhibits proliferation and fibrosis of cardiac fibroblasts. Reperfusion of the ischaemic myocardium by percutaneous coronary intervention (PCI) reduces the infarct size and improves left ventricular (LV) function in patients with acute myocardial infarction (AMI). However, the benefits of PCI in AMI are limited by reperfusion injury. Animal studies have shown that ANP inhibits ischaemia/reperfusion injury, and reduces infarct size. We and others have recently shown that the intravenous administration of ANP inhibits RAAS, sympathetic nerve activity and reperfusion injury, prevents LV remodelling, and improves LV function in patients with AMI. ANP has a variety of cardioprotective effects and is considered to be a very promising adjunct drug for the reperfusion therapy in patients with AMI.

Atrial natriuretic peptide reduces ischemia/reperfusion-induced spinal cord injury in rats by enhancing sensory neuron activation

We recently demonstrated that calcitonin gene-related peptide (CGRP) released from sensory neurons reduces spinal cord injury (SCI) by inhibiting neutrophil activation through an increase in the endothelial production of prostacyclin (PGI(2)). Carperitide, a synthetic alpha-human atrial natriuretic peptide (ANP), reduces ischemia/reperfusion (I/R)-induced tissue injury. However, its precise therapeutic mechanism(s) remains to be elucidated. In the present study, we examined whether ANP reduces I/R-induced spinal cord injury by enhancing sensory neuron activation using rats. ANP increased CGRP release and cellular cAMP levels in dorsal root ganglion neurons isolated from rats in vitro. The increase in CGRP release induced by ANP was reversed by pretreatment with capsazepine, an inhibitor of vanilloid receptor-1 activation, or with (9S, 10S, 12R)-2,3,9,10,11,12-hexahydro-10-hydroxy-9-methyl-1-oxo-9,12-epoxy-1H-diindolo[1,2,3-fg:3',2',1'-kl]pyrrolo[3,4-i][1,6]-benzodiazocine-10-carboxylic acid hexyl ester (KT5720), an inhibitor of protein kinase A (PKA), suggesting that ANP might increase CGRP release from sensory neurons by activating PKA through an increase in the cellular cAMP level. Spinal cord ischemia was induced in rats using a balloon catheter placed in the aorta. ANP reduced mortality and motor disturbances by inhibiting reduction of the number of motor neurons in animals subjected to SCI. ANP significantly enhanced I/R-induced increases in spinal cord tissue levels of CGRP and 6-keto-prostaglandin F(1alpha). a stable metabolite of PGI(2). ANP inhibited I/R-induced increases in spinal cord tissue levels of tumor necrosis factor and myeloperoxidase. Pretreatment with 4'-chloro-3-methoxycinnamanilide (SB366791), a specific vanilloid receptor-1 antagonist, and indomethacin reversed the effects of ANP. These results strongly suggest that ANP might reduce I/R-induced SCI in rats by inhibiting neutrophil activation through enhancement of sensory neuron activation.

In vivo dilatation of the postnatal ductus arteriosus by atrial natriuretic peptide in the rat

BACKGROUND

Alpha-human atrial natriuretic peptide (hANP) reportedly increases in premature infants with patent ductus arteriosus (PDA).

OBJECTIVES

To clarify a possible hANP effect to reopen the postnatal ductus, we studied in vivo reopening of the postnatal DA by a recombinant hANP, carperitide, in rats.

METHODS

Near-term rat pups were incubated at 33 degrees C following caesarean section. The inner diameter of the ductus was measured with a microscope and a micrometer following rapid whole-body freezing. The DA constricted quickly after birth, and the inner diameter was 0.80 and 0.08 mm at 0 min (fetal state) and 60 min after birth. hANP concentration in the pup blood and the ductus-dilating effect of hANP were studied by subcutaneous injection of hANP at 60 min after birth, and by measurement 7, 15, 30 and 60 min later.

RESULTS

The peak hANP concentration was 790 pg/ml at 7 min with 1 mg/kg, which is similar to the level seen in preterm infants with symptomatic PDA. hANP dilated the postnatal ductus dose dependently and maximally at 7 min after injection. hANP dilated the postnatal constricted ductus completely to 0.79 mm in diameter with a large dose (10 mg/kg) and to 0.55 mm with 1 mg/kg.

CONCLUSIONS

hANP reopens the constricted postnatal DA dose dependently in rats. The increased hANP, accompanying premature PDA, may delay closure of the DA.

Contemporary Issues in the Pharmacologic Management of Acute Heart Failure

Acute heart failure is an evolving syndrome that continues to be defined by ongoing studies and registries. It is associated with significant morbidity and mortality and places a huge economic burden on health care systems. Improved understanding of the underlying pathophysiologic processes has prompted interest into understanding the implications of current and future pharmacologic management strategies beyond hemodynamics. Diuretics, vasodilators, and inotropes remain the mainstays of therapy with several new classes of agents on the horizon. Clinicians should understand the rationale for use and limitations of each therapy to maximize benefit and cost-effectiveness, while minimizing the potential for adverse outcomes.

Natriuretic peptides as therapeutic targets

Natriuretic peptides (atrial natriuretic peptide, brain natriuretic peptide and C-type natriuretic peptide) are cardiac and vascular peptides with vasodilatory, diuretic, natriuretic, anti-inflammatory, antifibrotic and antimitogenic actions. Natriuretic peptides are implicated in normal pressure and volume homeostasis and in the defence against excessive increases in overload-related factors, vasopressive and cardiotoxic factors and their impact on the heart, blood vessels and brain. Genetic manipulation studies confirmed the importance of natriuretic peptides in these functions. Natriuretic peptides are metabolised by NPR-C (clearance receptors) and by enzymatic degradation by neutral endopeptidase. Natriuretic peptide levels (mainly brain natriuretic peptide) correlate with left ventricular hypertrophy and with the severity of heart failure, and are reduced by effective treatment, thus used as diagnostic and prognostic tools. Based on the multiple protective effects of natriuretic peptides, pharmacological therapy has been approved and includes potentiating natriuretic peptide levels by intravenous infusion or by inhibition of endogenous natriuretic peptide degradation. Because each approach has its limitations, the field remains open for improvement.

Cardiorenal syndrome in decompensated heart failure: Prognostic and therapeutic implications

Various lines of evidence implicate impaired renal function as an important prognostic indicator in patients with congestive heart failure (CHF). Conventional diuretics may aggravate renal dysfunction and can result in neurohumoral activation. Evolving new therapeutic strategies that enhance renal function include administration of B-type natriuretic peptide, adenosine and vasopressin antagonists, and ultrafiltration methods. Prospective studies are needed to evaluate whether these new renal-enhancing strategies will improve patient outcome in CHF.

Rationale and Design of a Large-Scale Trial Using Atrial Natriuretic Peptide (ANP) as an Adjunct to Percutaneous Coronary Intervention for ST-Segment Elevation Acute Myocardial Infarction-Japan-Working Groups of Acute Myocardial Infarction for the Reduction of Necrotic Damage by ANP (J-WIND-ANP)-

BACKGROUND

The benefits of percutaneous coronary intervention (PCI) in acute myocardial infarction (AMI) are limited by reperfusion injury. In animal models, atrial natriuretic peptide (ANP) reduces infarct size, so the Japan-Working groups of acute myocardial Infarction for the reduction of Necrotic Damage by ANP (J-WIND-ANP) designed a prospective, randomized, multicenter study, to evaluate whether ANP as an adjunctive therapy for AMI reduces myocardial infarct size and improves regional wall motion.

METHODS AND RESULTS

Twenty hospitals in Japan will participate in the J-WIND-ANP study. Patients with AMI who are candidates for PCI are randomly allocated to receive either intravenous ANP or placebo administration. The primary end-points are (1) estimated infarct size (Sigmacreatine kinase and troponin T) and (2) left ventricular function (left ventriculograms). Single nucleotide polymorphisms (SNPs) that may be associated with the function of ANP and susceptibility of AMI will be examined. Furthermore, a data mining method will be used to design the optimal combinational therapy for post-MI patients.

CONCLUSIONS

J-WIND-ANP will provide important data on the effects of ANP as an adjunct to PCI for AMI and the SNPs information will open the field of tailor-made therapy. The optimal therapeutic drug combination will also be determined for post-MI patients.

Synthesis and in vitro analysis of atrial natriuretic peptide–albumin conjugates

Atrial natriuretic peptide (ANP) is a clinically useful anti-hypertensive hormone. Maleimide derivatives of ANP have been synthesized and conjugated to cysteine-34 of human serum albumin. The conjugates were analyzed to assess their stability, receptor binding affinity and ability to stimulate guanylyl-cyclase activity in rat lung fibroblasts.

Preischemic infusion of alpha-human atrial natriuretic peptide elicits myoprotective effects against ischemia reperfusion in isolated rat hearts

Carperitide, a synthetic alpha-human atrial natriuretic peptide (ANP) is a newly developed drug for the treatment of heart failure. However, effects of carperitide on susceptibility to ischemia reperfusion injury are left to be determined. Isolated rat hearts were subjected to Langendorff perfusion. Six hearts received 0.1 microM of carperitide for 10 min, 6 hearts received 1 mM of a NO synthetase inhibitor N(G)-nitro-L-arginine methyl ester (L-NAME) for 5 min before the infusion of carperitide, 6 hearts received 0.02 microM of a PKC synthetase inhibitor chelerythrine chloride for 5 min before the infusion of carperitide, 6 hearts received 100 microM of a selective mitochondrial ATP-sensitive potassium (KATP) channel blocker 5-dehydroxydecanoate (5HD) before the infusion of carperitide, 6 hearts received 10 microM of a soluble guanylate cyclase inhibitor methylene blue for 5 min before the infusion of carperitide, and 6 hearts served as a control with no drug infusion. All hearts were then subjected to 20 min of global ischemia followed by 120 min of reperfusion. Left ventricular pressures and coronary flow were measured throughout the experiment and infarct size was detected at the end of experiment. Both plasma and tissue cGMP levels were also determined. The results showed: (1) Carperitide significantly reduced infarct size compared to control (26.1 +/- 2.8 vs. 42.7 +/- 2.3%, carperitide vs. control, p < 0.05). This effect was reversed by L-NAME, chelerythrine and 5HD, but not methylene blue. (2) Plasma cGMP levels were increased in carperitide-treated group. This effect was reversed by L-NAME (0.16 +/- 0.03 vs. 1.04 +/- 0.09* vs. 0.28 +/- 0.02 nmol/L, control vs. carperitide vs. L-NAME, *p < 0.01 vs. control). We conclude that preischemic infusion of carperitide exerts cardioprotective effects possibly through NO-PKC dependent pathway followed by mitochondrial KATP channel activation.