Magnifying endoscopic observation of the gastric mucosa, particularly in patients with atrophic gastritis

Urotensin II receptor deficiency ameliorates ligation-induced carotid intimal hyperplasia partially through the RhoA-YAP1 pathway

Intimal hyperplasia (IH) is a common pathological feature of vascular proliferative diseases, such as atherosclerosis and restenosis after angioplasty. Urotensin II (UII) and its receptor (UTR) are widely expressed in cardiovascular tissues. However, it remains unclear whether the UII/UTR system is involved in IH. Right unilateral common carotid artery ligation was performed and maintained for 21 days to induce IH in UTR knockout (UTR-/-) and wild-type (WT) mice. Histological analysis revealed that compared with WT mice, UTR-deficient mice exhibited a decreased neointimal area, angiostenosis and intima-media ratio. Immunostaining revealed fewer smooth muscle cells (SMCs), endothelial cells and macrophages in the lesions of UTR-/- mice than in those of WT mice. Protein interaction analysis suggested that the UTR may affect cell proliferation by regulating YAP and its downstream target genes. In vitro experiments revealed that UII can promote the proliferation and migration of SMCs, and western blotting also revealed that UII increased the protein expression of RhoA, CTGF, Cyclin D1 and PCNA and downregulated p-YAP protein expression, while these effects could be partly reversed by urantide. To evaluate the translational value of UTRs in IH management, WT mice were also treated with two doses of urantide, a UTR antagonist, to confirm the benefit of UTR blockade in IH progression. A high dose of urantide (600 μg/kg/day), rather than a low dose (60 μg/kg/day), successfully improved ligation-induced IH compared with that in mice receiving vehicle. The results of the present study suggested that the UII/UTR system may regulate IH partly through the RhoA-YAP signaling pathway.

Urotensin II system in chronic kidney disease

Chronic kidney disease (CKD) is a progressive and long-term condition marked by a gradual decline in kidney function. CKD is prevalent among those with conditions such as diabetes mellitus, hypertension, and glomerulonephritis. Affecting over 10% of the global population, CKD stands as a significant cause of morbidity and mortality. Despite substantial advances in understanding CKD pathophysiology and management, there is still a need to explore novel mechanisms and potential therapeutic targets. Urotensin II (UII), a potent vasoactive peptide, has garnered attention for its possible role in the development and progression of CKD. The UII system consists of endogenous ligands UII and UII-related peptide (URP) and their receptor, UT. URP pathophysiology is understudied, but alterations in tissue expression levels of UII and UT and blood or urinary UII concentrations have been linked to cardiovascular and kidney dysfunctions, including systemic hypertension, chronic heart failure, glomerulonephritis, and diabetes. UII gene polymorphisms are associated with increased risk of diabetes. Pharmacological inhibition or genetic ablation of UT mitigated kidney and cardiovascular disease in rodents, making the UII system a potential target for slowing CKD progression. However, a deeper understanding of the UII system's cellular mechanisms in renal and extrarenal organs is essential for comprehending its role in CKD pathophysiology. This review explores the evolving connections between the UII system and CKD, addressing potential mechanisms, therapeutic implications, controversies, and unexplored concepts.

Serum Urotensin II Levels Are Elevated in Patients with Obstructive Sleep Apnea

Obstructive sleep apnea (OSA) has become major public concern and is continuously investigated in new aspects of pathophysiology and management. Urotensin II (UII) is a powerful vasoconstrictor with a role in cardiovascular diseases. The main goal of this study was to evaluate serum UII levels in OSA patients and matched controls. A total of 89 OSA patients and 89 controls were consecutively enrolled. A medical history review and physical examination of the participants was conducted, with polysomnography performed in the investigated group. UII levels and other biochemical parameters were assessed according to the standard laboratory protocols. The median AHI in the OSA group was 39.0 (31.4-55.2) events/h, and they had higher levels of hsCRP when compared to control group (2.87 ± 0.71 vs. 1.52 ± 0.68 mg/L; p < 0.001). Additionally, serum UII levels were significantly higher in the OSA group (3.41 ± 1.72 vs. 2.18 ± 1.36 ng/mL; p < 0.001), while positive correlation was found between UII levels and hsCRP (r = 0.450; p < 0.001) and systolic blood pressure (SPB) (r = 0.317; p < 0.001). Finally, multiple regression analysis showed significant association of UII levels with AHI (0.017 ± 0.006, p = 0.013), SBP (0.052 ± 0.008, p < 0.001) and hsCRP (0.538 ± 0.164, p = 0.001). As UII levels were associated with blood pressure and markers of inflammation and OSA severity, it might play an important role in the complex pathophysiology of OSA and its cardiometabolic complications.

The urotensin-II receptor: A marker for staging and steroid outcome prediction in ulcerative colitis

BACKGROUND

Urotensin-II receptor- (UTR) related pathway exerts a key-role in promoting inflammation. The aim was to assess the relationship between UTR expression and clinical, endoscopic and biochemical severity of ulcerative colitis (UC), exploring its predictivity of intravenous (iv) steroid administration therapeutic outcome.

METHODS

One-hundred patients with first diagnosis of UC and 44 healthy subjects were enrolled. UTR expression was assessed by qPCR, Western Blot (WB) and immunohistochemistry (IHC). Clinical, endoscopic and histological activity of UC were evaluated by using Truelove and Witts (T&W) severity index, Mayo Endoscopic Score (MES), and Truelove and Richards Index (TRI). The partial and full Mayo scores (PMS and FMS) were assessed to stage the disease.

RESULTS

The UTR expression, resulted higher in the lesioned mucosa of UC patients in comparison to healthy subjects (p < .0001 all). Direct relationship between UTR (mRNA and protein) expression and disease severity assessment (T&W, PMS, MES and TRI) was highlighted (p < .0001 all). UTR expression resulted also higher in the 72 patients requiring iv steroids administration compared to those who underwent alternative medications, (p < .0001). The 32 steroid-non-responders showed an increased UTR expression (WB, IHC and qPCR from lesioned mucosa), compared to 40 steroid-responders (p: .0002, .0001, p < .0001 respectively). The predictive role of UTR expression (p < .05) on the negative iv steroids administration therapeutic outcome was highlighted and ROC curves identified the thresholds expressing the better predictive performance.

CONCLUSIONS

UTR represents a promising inflammatory marker related to clinical, endoscopic, and histological disease activity as well as a predictive marker of steroid administration therapeutic outcome in the UC context.

The network map of urotensin-II mediated signaling pathway in physiological and pathological conditions

Urotensin-II is a polypeptide ligand with neurohormone-like activity. It mediates downstream signaling pathways through G-protein-coupled receptor 14 (GPR14) also known as urotensin receptor (UTR). Urotensin-II is the most potent endogenous vasoconstrictor in mammals, promoting cardiovascular remodelling, cardiac fibrosis, and cardiomyocyte hypertrophy. It is also involved in other physiological and pathological activities, including neurosecretory effects, insulin resistance, atherosclerosis, kidney disease, and carcinogenic effects. Moreover, it is a notable player in the process of inflammatory injury, which leads to the development of inflammatory diseases. Urotensin-II/UTR expression stimulates the accumulation of monocytes and macrophages, which promote the adhesion molecules expression, chemokines activation and release of inflammatory cytokines at inflammatory injury sites. Therefore, urotensin-II turns out to be an important therapeutic target for the treatment options and management of associated diseases. The main downstream signaling pathways mediated through this urotensin-II /UTR system are RhoA/ROCK, MAPKs and PI3K/AKT. Due to the importance of urotensin-II systems in biomedicine, we consolidated a network map of urotensin-II /UTR signaling. The described signaling map comprises 33 activation/inhibition events, 31 catalysis events, 15 molecular associations, 40 gene regulation events, 60 types of protein expression, and 11 protein translocation events. The urotensin-II signaling pathway map is made freely accessible through the WikiPathways Database ( https://www.wikipathways.org/index.php/Pathway:WP5158 ). The availability of comprehensive urotensin-II signaling in the public resource will help understand the regulation and function of this pathway in normal and pathological conditions. We believe this resource will provide a platform to the scientific community in facilitating the identification of novel therapeutic drug targets for diseases associated with urotensin-II signaling.

The Inhibitory Role of Hydrogen Sulfide in UII-Induced Cardiovascular Effects and the Underlying Signaling Pathways

Urotensin II (UII) could increase blood pressure and heart rate via increased central reactive oxygen species (ROS) levels. We reported previously that hydrogen sulfide (H2S) exerts an antihypertensive effect by suppressing ROS production. The aim of the current study is to further examine the effects of endogenous and exogenous H2S on UII-induced cardiovascular effects by using an integrated physiology approach. We also use cell culture and molecular biological techniques to explore the inhibitory role of H2S on UII-induced cardiovascular effects. In this study, we found that cystathionine-β-synthase (CBS), the main H2S synthesizing enzyme in CNS, was expressed in neuronal cells of the rostral ventrolateral medulla (RVLM) area. Cellular distribution of CBS and urotensin II receptor (UT) in SH-SY5Y cells that are confirmed as glutamatergic were identified by immunofluorescent and Western blots assay. In Sprague-Dawley rats, administration of UII into the RVLM resulted in an increase in mean arterial pressure (MAP), heart rate (HR), ROS production, nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activity, and phosphorylation of p47phox, extracellular signal-regulated protein kinase (ERK)1/2 and p38MAPK, but not stress-activated protein kinase/Jun N-terminal kinase (SAPK/JNK). These effects of UII were attenuated by application into the RVLM of endogenous (L-cysteine, SAM) or exogenous (NaHS) H2S. These results were confirmed in SH-SY5Y cells. UII-induced cardiovascular effects were also significantly abolished by pretreatment with microinjection of Tempol, Apocynin, SB203580, or PD98059 into the RVLM. Preincubated SH-SY5Y cells with Apocynin before administration of UII followed by Western blots assay showed that ROS is in the upstream of p38MAPK/ERK1/2. Gao activation assay in SH-SY5Y cells suggested that H2S may exert an inhibitory role on UII-induced cardiovascular effects by inhibiting the activity of Gαo. These results suggest that both endogenous and exogenous H2S attenuate UII-induced cardiovascular effects via Gαo-ROS-p38MAPK/ERK1/2 pathway.

Novel insights into the role of urotensin II in cardiovascular disease

Urotensin II (UII) is a vasoactive peptide that interacts with a specific receptor called the UT receptor. UII has been implicated in cardiovascular regulation, with promising therapeutic applications based on UT receptor antagonism. The endogenous ligands of the UT receptor: UII and urotensin-related peptide (URP), differentially bind and activate this receptor. Also, the receptor localization is not restricted to the plasma membrane, possibly inducing different physiological responses that could support its inconsistent, but potent, vasoactive activity. These properties could explain the disappointing outcomes in clinical studies, in contrast to the positive preclinical results regarding heart failure, pulmonary hypertension, atherosclerosis and diabetes mellitus. These aspects should be considered in future investigations to a better comprehension of the role of UII as a potential therapeutic target.

The role of human urotensin-II in patients with hypertrophic cardiomyopathy

OBJECTIVE

Hypertrophic cardiomyopathy (HCM) is a genetic condition with the hallmark feature of left ventricular hypertrophy. Human Urotensin-II (hUT-II) is regarded as a cardiovascular autacoid/hormone, and it has cardiac inotropic and hypertrophic properties. Aims of this study were to elucidate the clinical significance of serum hUT-II levels as a potential new biomarker in patients with HCM.

METHODS

This study included 40 HCM patients (60% males and 40% females) and were compared to 30 healthy control subjects (47% males and 53% females. All patients underwent extensive clinical, laboratory, and echocardiographic. Blood samples were taken to test for serum hUT-II levels by commercial ELISA Kit.

RESULTS

Serum hUT-II was significantly higher (p < 0.01) in patients with HCM (15.8 ± 2.1 pmol/L) compared with healthy controls (3.3 ± 1.7 pmol/L). With regard to HCM patient, Serum hUT-II levels were significantly higher in the female with 16.3 ± 1.9 pmol/L than the male with 15.4 ± 2.2 pmol/L (p < 0.05). Among echocardiographic parameters, hUT-II was negatively associated with ejection fraction (r = -0.160, p = 0.324).

CONCLUSION

Results of the first study indicated that serum hUT-II levels were markedly elevated in patients with HCM. Serum hUT-II is a novel biomarker parameter that has clinical use in patients with the severity of LVH.

Urotensin-II peptidomimetic incorporating a non-reducible 1,5-triazole disulfide bond reveals a pseudo-irreversible covalent binding mechanism to the urotensin G-protein coupled receptor

New high affinity peptidomimetic ligands have been developed that provided new insight into the mechanism of binding of U-II peptide with the urotensin-II receptor.

Age-Related Reduction of Contractile Responses to Urotensin II Is Seen in Aortas from Wistar Rats but Not from Type 2 Diabetic Goto-Kakizaki Rats

Vascular dysfunction is a common finding in type 2 diabetes, although the response to urotensin II (UII), a potent vasoconstrictor peptide, remains unclear. We investigated whether a UII-induced contraction was increased in the aortas from type 2 diabetic Goto-Kakizaki (GK) rats at the chronic stage. At 36 or 37 weeks of age (older group), a UII-induced contraction was seen in GK rats and was reduced by a Rho kinase inhibitor or urotensin receptor (UT) antagonist, whereas UII failed to induce a contraction in aortas from age-matched Wistar rats. In UII-stimulated aortas, the expression of Rho kinases, Rho A, and phosphorylated myosin phosphatase target subunit 1 did not change between the two groups; however, phosphorylation of extracellular-regulated kinase 1/2 and p38 mitogen-activated protein kinase (MAPK) was greater in GK than in Wistar rats. Compared to intact aortas, UII-induced contractions were slightly, but not significantly, increased by endothelial denudation of the aortas of Wistar rats at 24 weeks of age. At 6 weeks of age (young group), the UII-induced contractions were seen in GK and Wistar groups. The total expression and the membrane-to-cytosol ratio of the UT protein slightly decreased in Wistar aortas with aging but not in GK aortas. These results demonstrate that the UII-induced contraction gradually decreased with aging in Wistar rats and was preserved in type 2 diabetes. Although alterations of UII-induced contractions during aging and type 2 diabetes may be associated with kinase activities (MAPKs or Rho kinase) or receptor profiles, further investigations are necessary to clarify the mechanisms.

Renal Urotensin II System Plays Roles in the Regulation of Blood Pressure in Dahl Salt-Resistant Rat

Introduction. Dahl salt-resistant (SR) animal models are similar to peritoneal dialysis patients with fluid volumes overload with normal blood pressure in hemodynamic profiles. We will verify the roles of UII in the regulation of blood pressure in these animal models. Methodology. The Dahl salt-sensitive (SS) and SR rats and UII receptor gene knocked out (KO) mice were placed on a high-salt diet. Renal tissues were performed for the expression of UII in Dahl groups. Results. After high-salt diet for 6 weeks, the systolic blood pressure (SBP) in SR group was significantly lower, accompanied with higher urinary UII levels, higher 24-hour urinary sodium excretion, and higher urinary creatinine clearance in the SR rats in comparison to SS group. The expressions of UII and UT were both upregulated in the kidney tissues of SR group in comparison to SS group (P < 0.05). After high-salt diet for 8 weeks, the SBP of the KO group is significantly higher than that of the wild type group. Conclusion. We first demonstrate that renal UII system can play important roles in the regulation of blood pressure in Dahl SR rats which can be highly correlated to its effect on renal tubular sodium absorption.

Attenuation of renovascular hypertension by cyclooxygenase-2 inhibitor partly through ANP release

Angiotensin II (Ang II) is an important inflammatory mediator. Ang II induces cyclooxygenase-2 (COX-2) expression and prostaglandin F2α release followed by cardiac hypertrophy. Inhibition of COX-2 may modulate high blood pressure but controversy still exists. The aim of this study was to determine the role of COX-2 in the regulation of blood pressure and to define the mechanisms in two kidney one-clip hypertensive (2K1C) rats. Chronic treatment with nimesulide or NS-398 (5 mg/kg/day) for 3 weeks lowered high blood pressure and cardiac hypertrophy with decreased expression levels of cardiac hypertrophy markers [atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP)], Ang type 1 receptor, urotensin II, and urotensin II receptor in 2K1C rats. Plasma level of ANP was markedly increased and plasma levels of Ang II and aldosterone were decreased by treatment with nimesulide or NS-398. In both in vitro and in vivo experiments, nimesulide or NS-398 augmented ANP release in 2K1C rats. The inhibitory effect of NS-398 on blood pressure was attenuated by the pretreatment with natriuretic peptide receptor-A (NPR-A) antagonist (A71915, 30 μg/kg/day). These results suggest that chronic treatment with nimesulide or NS-398 attenuated hypertension and cardiac hypertrophy partly through ANP release in 2K1C rats.

Urotensin II Protects Cardiomyocytes from Apoptosis Induced by Oxidative Stress through the CSE/H2S Pathway

Plasma urotensin II (UII) has been observed to be raised in patients with acute myocardial infarction; suggesting a possible cardiac protective role for this peptide. However, the molecular mechanism is unclear. Here, we treated cultured cardiomyocytes with H₂O₂ to induce oxidative stress; observed the effect of UII on H₂O₂-induced apoptosis and explored potential mechanisms. UII pretreatment significantly reduced the number of apoptotic cardiomyocytes induced by H₂O₂; and it partly abolished the increase of pro-apoptotic protein Bax and the decrease of anti-apoptotic protein Bcl-2 in cardiomyocytes induced by H₂O₂. SiRNA targeted to the urotensin II receptor (UT) greatly inhibited these effects. Further analysis revealed that UII increased the production of hydrogen sulfide (H₂S) and the level of cystathionine-γ-lyase (CSE) by activating the ERK signaling in H₂O₂-treated-cardiomyocytes. Si-CSE or ERK inhibitor not only greatly inhibited the increase in CSE level or the phosphorylation of ERK induced by UII but also reversed anti-apoptosis of UII in H₂O₂-treated-cadiomyocytes. In conclusion, UII rapidly promoted the phosphorylation of ERK and upregulated CSE level and H₂S production, which in turn activated ERK signaling to protect cardiomyocytes from apoptosis under oxidative stress. These results suggest that increased plasma UII level may protect cardiomyocytes at the early-phase of acute myocardial infarction in patients.

Can early myocardial infarction-related deaths be diagnosed using postmortem urotensin receptor expression levels?

PURPOSE

Myocardial infarction (MI) is one of the most prevalent causes of sudden adult death. It is difficult to diagnose early MI postmortem because there are no typical or characteristic changes in morphology. In this study, changes in the level of the mRNA for the urotensin receptor (UR) were investigated postmortem to determine the suitability of UR as a biomarker for diagnosis of early MI after death.

METHODS

An MI rat model was developed by injecting rats with isoproterenol (ISO) (lethal dose 850 mg/kg) or normal saline (control group). The hearts of rats in the control and ISO-induced MI groups were harvested at 0, 1, 3, 6, 12, 24, 48, and 72 h (h) postmortem. The hearts were then immediately submerged in 1 mL of RNA stabilization solution and stored at 4 °C for <1 week before RNA extraction. Relative UR expression analysis was performed using the StepOne Plus Real Time PCR System with cDNA synthesized from rat heart.

RESULTS

Postmortem UR mRNA expression was higher in the ISO-induced MI group than in the control group, at both 4 and 20 °C, at all of the time points examined except 72 h postmortem (p < 0.0001). The largest increases were observed at ambient temperature and 6 h postmortem.

CONCLUSIONS

Based on our findings, increased postmortem UR expression could serve as a biomarker to aid diagnosis of early MI.

Angiotensin II and the JNK pathway mediate urotensin II expression in response to hypoxia in rat cardiomyocytes

Cardiomyocyte hypoxia causes cardiac hypertrophy through cardiac-restricted gene expression. Urotensin II (UII) cooperates with activating protein 1 (AP1) to regulate cardiomyocyte growth in response to myocardial injuries. Angiotensin II (AngII) stimulates UII expression, reactive oxygen species (ROS) production, and cardiac hypertrophy. This study aimed to evaluate the expression of UII, ROS, and AngII as well as their genetic transcription after hypoxia treatment in neonatal cardiomyocytes. Cultured neonatal rat cardiomyocytes were subjected to hypoxia for different time periods. UII (Uts2) protein levels increased after 2.5% hypoxia for 4 h with earlier expression of AngII and ROS. Both hypoxia and exogenously added AngII or Dp44mT under normoxia stimulated UII expression, whereas AngII receptor blockers, JNK inhibitors (SP600125), JNK siRNA, or N-acetyl-l-cysteine (NAC) suppressed UII expression. The gel shift assay indicated that hypoxia induced an increase in DNA-protein binding between UII and AP1. The luciferase assay confirmed an increase in transcription activity of AP1 to the UII promoter under hypoxia. After hypoxia, an increase in (3)H-proline incorporation in the cardiomyocytes and expression of myosin heavy chain protein, indicative of cardiomyocyte hypertrophy, were observed. In addition, hypoxia increased collagen I expression, which was inhibited by SP600125, NAC, and UII siRNA. In summary, hypoxia in cardiomyocytes increases UII and collagen I expression through the induction of AngII, ROS, and the JNK pathway causing cardiomyocyte hypertrophy and fibrosis.

Arrestins in apoptosis

Programmed cell death (apoptosis) is a coordinated set of events eventually leading to the massive activation of specialized proteases (caspases) that cleave numerous substrates, orchestrating fairly uniform biochemical changes than culminate in cellular suicide. Apoptosis can be triggered by a variety of stimuli, from external signals or growth factor withdrawal to intracellular conditions, such as DNA damage or ER stress. Arrestins regulate many signaling cascades involved in life-or-death decisions in the cell, so it is hardly surprising that numerous reports document the effects of ubiquitous nonvisual arrestins on apoptosis under various conditions. Although these findings hardly constitute a coherent picture, with the same arrestin subtypes, sometimes via the same signaling pathways, reported to promote or inhibit cell death, this might reflect real differences in pro- and antiapoptotic signaling in different cells under a variety of conditions. Recent finding suggests that one of the nonvisual subtypes, arrestin-2, is specifically cleaved by caspases. Generated fragment actively participates in the core mechanism of apoptosis: it assists another product of caspase activity, tBID, in releasing cytochrome C from mitochondria. This is the point of no return in committing vertebrate cells to death, and the aspartate where caspases cleave arrestin-2 is evolutionary conserved in vertebrate, but not in invertebrate arrestins. In contrast to wild-type arrestin-2, its caspase-resistant mutant does not facilitate cell death.

The relationship of urotensin II with insulin resistance and hs-CRP in patients having PCOS

UrotensinII (UII), one of the most potent vasoconstrictor proteins, may be associated with insulin resistance. The objective of our research was to determine the level of UII in sera of patients with PCOS and to investigate the relationship between UII and insulin resistance in patients with PCOS. Fourty seven PCOS patients and 42 healthy women were included in the study. Serum fasting glucose, insulin, UII, free testosterone and hs-CRP levels of the patients were examined. The HOMA-IR formula was used to calculate insulin resistance. Insulin sensitivity was calculated by using the QUICKI-IS formula. The two groups did not show any a significant difference in terms of age and BMI (p > 0.05). Serum UII, hs-CRP, insulin levels and the HOMA-IR were significantly higher in the patients with PCOS (p < 0.05). In the analysis of the correlation, UII and HOMA-IR showed statistically significant, moderately strong and positive correlation(r = 044, p < 0.001). UII and QUICKI-IS showed statistically significant, moderately strong and negative correlation(r = -0.44, p < 0.001). Also, a significant and positive correlation was found between with UII and hs-CRP(r = 0.51, p < 0.001). Our study data suggested that UII may have a role in the pathophysiology of insulin resistance and increased cardiovascular risk, which are commonly found in patients with PCOS.

Progress in understanding role of urotensin Ⅱ in hepatic cirrhosis

Urotensin Ⅱ (UⅡ) is a potent vasoactive substance that can result in vasoactive response through interaction with its specific orphan G-protein-coupled receptor GPR-14. In addition to the role of vasoactivity, UⅡ can promote mitosis and fibrosis. The vascular role of UⅡ is to some degree both species- and disease-specific. Studies have found that plasma levels of UⅡ are elevated in patients with cirrhosis, but the relationship between plasma levels of UⅡ and the development of chronic liver disease and portal hypertension has yet to be fully elucidated. This review focuses on the potential relevance of UⅡ as vasoactive substance in chronic liver disease and the site where UⅡ is overproduced.

Molecular models of the cardiorenal syndrome

Molecular profiling techniques have provided extensive sets of molecular features characterizing clinical phenotypes, but further extrapolation to mechanistic molecular models of disease pathophysiology faces major challenges. Here, we describe a computational procedure for delineating molecular disease models utilizing omics profiles, and exemplify the methodology on aspects of the cardiorenal syndrome describing the clinical association of declining kidney function and increased cardiovascular event rates. Individual molecular features as well as selected molecular processes were identified as linking cardiovascular and renal pathology as a combination of cross-organ mediators and common pathophysiology. The molecular characterization of the disease presents as a set of molecular processes together with their interactions, composing a molecular disease model of the cardiorenal syndrome. Integrating omics profiles describing aspects of cardiovascular disease and respective profiles for advanced chronic kidney disease on molecular interaction networks, computation of disease term-specific subgraphs, and complemented by subgraph segmentation allowed delineation of disease term-specific molecular models, at their intersection providing contributors to cardiorenal pathology. Building such molecular disease models allows in a generic way to integrate multi-omics sources for generating comprehensive sets of molecular processes, on such basis providing rationale for biomarker panel selection for further characterizing clinical phenotypes.

Urotensin-II Ligands: An Overview from Peptide to Nonpeptide Structures

Urotensin-II was originally isolated from the goby urophysis in the 1960s as a vasoactive peptide with a prominent role in cardiovascular homeostasis. The identification of human isoform of urotensin-II and its specific UT receptor by Ames et al. in 1999 led to investigating the putative role of the interaction U-II/UT receptor in multiple pathophysiological effects in humans. Since urotensin-II is widely expressed in several peripheral tissues including cardiovascular system, the design and development of novel urotensin-II analogues can improve knowledge about structure-activity relationships (SAR). In particular, since the modulation of the U-II system offers a great potential for therapeutic strategies related to the treatment of several diseases, like cardiovascular diseases, the research of selective and potent ligands at UT receptor is more fascinating. In this paper, we review the developments of peptide and nonpeptide U-II structures so far developed in order to contribute also to a more rational and detectable design and synthesis of new molecules with high affinity at the UT receptor.

Role of urotensin-Ⅱ in the pathogenesis of liver cirrhosis and portal hypertension and collateral circulation

Urotensin-Ⅱ (U-Ⅱ) is a somatostatin-like cyclic peptide which has a potent vasoactive effect and can promote vascular reconstruction and hyperplasia. Research shows that UⅡ plays an important role in the development of liver cirrhosis and portal hypertension. UⅡ influences intrahepatic resistance and splanchnic hemodynamics through a variety of pathways, causing portal hypertension and participating in the formation of esophageal and gastric varices. UⅡ receptor antagonists can reduce portal pressure in cirrhotic rats, but this finding need to be confirmed clinically.

Receptors, endocytosis, and trafficking: the biological basis of targeted delivery of antisense and siRNA oligonucleotides

The problem of targeted delivery of antisense and siRNA oligonucleotides can be resolved into two distinct aspects. The first concerns devising ligand-oligonucleotide or ligand-carrier moieties that bind with high selectivity to receptors on the cell type of interest and that are efficiently internalized by endocytosis. The second concerns releasing oligonucleotides from pharmacologically inert endomembrane compartments so that they can access RNA in the cytosol or nucleus. In this review, we will address both of these aspects. Thus, we present information on three important receptor families, the integrins, the receptor tyrosine kinases, and the G protein-coupled receptors in terms of their suitability for targeted delivery of oligonucleotides. This includes discussion of receptor abundance, internalization and trafficking pathways, and the availability of suitable high affinity ligands. We also consider the process of oligonucleotide uptake and intracellular trafficking and discuss approaches to modulating these processes in a pharmacologically productive manner. Hopefully, the basic information presented in this review will be of value to investigators involved in designing delivery approaches for oligonucleotides.

Urotensin II protects ischemic reperfusion injury of hearts through ROS and antioxidant pathway

Urotensin II (UII) is a vasoactive peptide which is bound to a G protein-coupled receptor. UII and its receptor are upregulated in ischemic and chronic hypoxic myocardium, but the effect of UII on ischemic reperfusion (I/R) injury is still controversial. The aim of the present study was to investigate whether UII protects heart function against I/R injury. Global ischemia was performed using isolated perfused Langendorff hearts of Sprague-Dawley rats. Hearts were perfused with Krebs-Henseleit buffer for 20min pre-ischemic period followed by a 20min global ischemia and 50min reperfusion. Pretreatment with UII (10nM) for 10min increased recovery percentage of the post-ischemic left ventricular developed pressure and ±dp/dt, and decreased post-ischemic left ventricular end-diastolic pressure as compared with I/R group. UII decreased infarct size and an increased lactate dehydrogenase level during reperfusion. Cardioprotective effects of UII were attenuated by pretreatment with UII receptor antagonist. The hydrogen peroxide activity was increased in UII-treated heart before ischemia. The Mn-SOD, catalase, heme oxygenase-1 and Bcl-2 levels were increased, and the Bax and caspase-9 levels were decreased in UII-treated hearts. These results suggest that UII has cardioprotective effects against I/R injury partly through activating antioxidant enzymes and reactive oxygen species.

Is plasma urotensin II concentration an indicator of myocardial damage in patients with acute coronary syndrome?

INTRODUCTION

Urotensin II (UII) is a vasoactive peptide secreted by endothelial cells. Increased plasma UII concentration was observed in patients with heart failure, liver cirrhosis, diabetic nephropathy and renal insufficiency. In patients with myocardial infarction both increased and decreased plasma UII concentrations were demonstrated. The aim of this study was to analyze whether plasma UII concentration reflects the severity of acute coronary syndrome (ACS).

MATERIAL AND METHODS

One hundred and forty-nine consecutive patients with ACS, without age limit, were enrolled in the study. In all patients plasma concentration of creatinine, creatine kinase isoenzyme MB (CK-MB), troponin C, N-terminal prohormone of brain natriuretic peptide (NT-pro BNP), and UII were assessed, and echocardiography was performed in order to assess the degree of left ventricular hypertrophy, ejection fraction (EF) and mass (LVM).

RESULTS

In patients with the highest risk (TIMI 5-7) plasma UII concentration was significantly lower than in those with low risk (TIMI 1-2): 2.61±1.47 ng/ml vs. 3.60±2.20 ng/ml. Significantly lower plasma UII concentration was found in patients with increased concentration of troponin C (2.60±1.52 ng/ml vs. 3.41±2.09 ng/ml). There was a significant negative correlation between plasma UII concentration and TIMI score or concentration of troponin C, but not CK-MB. Borderline correlation between plasma UII and ejection fraction (R = 0.157; p=0.063) or NT-proBNP (R = - 0.156; p=0.058) was found.

CONCLUSIONS

Decreased plasma urotensin II concentration in patients with ACS could be associated with more severe injury of myocardium.

Urotensin II levels in patients with chronic kidney disease and kidney transplants

OBJECTIVE

Urotensin II is a potent vasoactive peptide that has been implicated in the pathophysiology of many diseases. There is no study reporting the role and level of this peptide in recipients of kidney transplant. So we aimed to study the plasma levels of urotensin II in this group of patients.

METHODS

Plasma urotensin II levels were analyzed in 110 subjects, who were divided into three groups: group 1 (35 kidney transplant recipients), group 2 (36 patients with chronic kidney disease), and group 3 (39 healthy controls).

RESULTS

Analysis of logarithmic transformation of urotensin II, i.e. log (urotensin II × 1000) levels, with a one-way analysis of variance yielded a P value of 0.001. Post-hoc analysis showed significantly higher log (urotensin II × 1000) levels in group 1 than groups 2 and 3 (P = 0.001 and 0.017, respectively). One of the important features of the subjects of this group was that they were taking immunosuppressive drugs because of renal transplantation.

CONCLUSIONS

High urotensin II levels in recipients of kidney transplants could be drug-related (immunosuppressive drugs) and may be of practical importance that may be used to improve the long-term outcome of the patients.

Endogenous urotensin II selectively modulates erectile function through eNOS

Background

Urotensin II (U-II) is a cyclic peptide originally isolated from the neurosecretory system of the teleost fish and subsequently found in other species, including man. U-II was identified as the natural ligand of a G-protein coupled receptor, namely UT receptor. U-II and UT receptor are expressed in a variety of peripheral organs and especially in cardiovascular tissue. Recent evidence indicates the involvement of U-II/UT pathway in penile function in human, but the molecular mechanism is still unclear. On these bases the aim of this study is to investigate the mechanism(s) of U-II-induced relaxation in human corpus cavernosum and its relationship with L-arginine/Nitric oxide (NO) pathway.

Methodology/Principal Findings

Human corpus cavernosum tissue was obtained following in male-to-female transsexuals undergoing surgical procedure for sex reassignment. Quantitative RT-PCR clearly demonstrated the U-II expression in human corpus cavernosum. U-II (0.1 nM–10 µM) challenge in human corpus cavernosum induced a significant increase in NO production as revealed by fluorometric analysis. NO generation was coupled to a marked increase in the ratio eNOS phosphorilated/eNOS as determined by western blot analysis. A functional study in human corpus cavernosum strips was performed to asses eNOS involvement in U-II-induced relaxation by using a pharmacological modulation. Pre-treatment with both wortmannin or geldanamycinin (inhibitors of eNOS phosphorylation and heath shock protein 90 recruitment, respectively) significantly reduced U-II-induced relaxation (0.1 nM–10 µM) in human corpus cavernosum strips. Finally, a co-immunoprecipitation study demonstrated that UT receptor and eNOS co-immunoprecipitate following U-II challenge of human corpus cavernosum tissue.

Conclusion/Significance

U-II is endogenously synthesized and locally released in human corpus cavernosum. U-II elicited penile erection through eNOS activation. Thus, U-II/UT pathway may represent a novel therapeutical target in erectile dysfunction.

Angiotensin II mediates urotensin II expression by hypoxia in cultured cardiac fibroblast

BACKGROUND

Urotensin II plays a role in myocardial remodelling. Cardiac fibroblasts play a critical role in the development of cardiac fibrosis. The effect of hypoxia on urotensin II expression in cardiac fibroblasts is poorly understood. We sought to investigate the regulation of urotensin II by hypoxia in cardiac fibroblasts and the effect of angiotensin II in the interaction with urotensin II.

METHODS AND RESULTS

Rat cardiac fibroblasts were cultured in hypoxic chamber. Hypoxia significantly increased urotensin II expression and reactive oxygen species (ROS) production in cultured cardiac fibroblasts. Hypoxia-induced increase in urotensin II protein and ROS was significantly attenuated after the addition of SP600125, JNK siRNA or N-acetylcysteine before hypoxia treatment. The phosphorylated JNK protein was induced by hypoxia and was abolished by pretreatment with SP600125, losartan (an angiotensin II receptor antagonist) or N-acetylcysteine. The increased urotensin II expression by exogenous addition of angiotensin II was similar to that by hypoxia. Addition of losartan and angiotensin II antibody before hypoxia almost completely inhibited the increase in urotensin II induced by hypoxia. Hypoxia significantly increased the secretion of angiotensin II from cardiac fibroblasts and increased the collagen I protein expression. Hypoxia significantly increased the urotensin II promoter activity by 4·3-fold as compared to normoxic control. Urotensin II siRNA almost completely attenuated the collagen I protein expression induced by hypoxia.

CONCLUSIONS

Hypoxia-induced urotensin II expression in cardiac fibroblast is mediated by angiotensin II and through ROS and JNK pathway. Urotensin II is a mediator of angiotensin II-induced cardiac fibrosis under hypoxia.

A closer look at the role of urotensin II in the metabolic syndrome

Urotensin II (UII) is a vasoactive peptide that was first discovered in the teleost fish, and later in mammals and humans. UII binds to the G protein coupled receptor GPR14 (now known as UT). UII mediates important physiological and pathological actions by interacting with its receptor. The metabolic syndrome (MetS) is described as cluster of factors such as obesity, dyslipidemia, hypertension, and insulin resistance (IR), further leading to development of type 2 diabetes mellitus and cardiovascular diseases. UII levels are upregulated in patients with the MetS. Evidence directly implicating UII in every risk factor of the MetS has been accumulated. The mechanism that links the different aspects of the MetS relies primarily on IR and inflammation. By directly modulating both of these factors, UII is thought to play a central role in the pathogenesis of the MetS. Moreover, UII also plays an important role in hypertension and hyperlipidemia thereby contributing to cardiovascular complications associated with the MetS.

Association Between Thr21Met and Ser89Asn Polymorphisms of the Urotensin II Gene and Systemic Sclerosis

Objective.

Systemic sclerosis (SSc) is an autoimmune chronic fibrotic disorder. Urotensin II (U-II) is predominantly a vasoactive peptide with fibrotic and prothrombotic features. Like endothelin-1 (ET-1), U-II could play an important role in SSc pathogenesis. We evaluated the possible role of the U-II gene polymorphisms (Thr21Met and Ser89Asn) in the genetic susceptibility to SSc in a Turkish population.

Methods.

A total of 189 patients with SSc and 205 healthy controls were enrolled in our study. We analyzed the genotype and allele frequencies of the U-II (UTS2) gene polymorphisms Thr21Met and Ser89Asn in patients with SSc and in controls.

Results.

We found that the Thr21Met polymorphism of the UTS2 gene was markedly associated with the risk of developing SSc (p < 0.0001), but there was no relationship between the Ser89Asn polymorphism and SSc (p > 0.05). Two haplotypes (MS and TS) were markedly associated with SSc (p < 0.05). There were significant associations between the genotype and allele frequencies of UTS2 gene Thr21Met polymorphism and cases with diffuse or limited SSc, systemic or lung involvement, finger flexion deformity, pitting scars at the fingertips, positive anticentromere, or positive antitopoisomerase 1 antibody groups.

Conclusion.

Our study shows the association between Thr21Met, but not Ser89Asn, in the UTS2 gene and SSc. The results strongly suggest that this single-nucleotide polymorphism may be an important risk factor in the development of SSc, and a powerful indicator of severe skin and lung involvement in patients with SSc.

Potential Clinical Implications of the Urotensin II Receptor Antagonists

Urotensin II (UII) binds to its receptor, UT, playing an important role in the heart, kidneys, pancreas, adrenal gland, and central nervous system. In the vasculature, it acts as a potent endothelium-independent vasoconstrictor and endothelium-dependent vasodilator. In disease states, however, this constriction–dilation equilibrium is disrupted. There is an upregulation of the UII system in heart disease, metabolic syndrome, and kidney failure. The increase in UII release and UT expression suggest that UII system may be implicated in the pathology and pathogenesis of these diseases by causing an increase in acyl-coenzyme A:cholesterol acyltransferase-1 (ACAT-1) activity leading to smooth muscle cell proliferation and foam cell infiltration, insulin resistance (DMII), as well as inflammation, high blood pressure, and plaque formation. Recently, UT antagonists such as SB-611812, palosuran, and most recently a piperazino-isoindolinone based antagonist have been developed in the hope of better understanding the UII system and treating its associated diseases.

The interaction between human urotensin II and vasodilator agents in human internal mammary artery with possible clinical implications

BACKGROUND

Graft spasm in the internal mammary artery (IMA) may occur after coronary artery bypass grafting (CABG). We investigated the effect of human urotensin II (hU-II), a cyclic peptide hormone present in human blood and tissues, and the effect of vasodilators on hU-II-mediated response in human IMA.

METHODS

Fresh IMA segments (n=114) taken from 50 patients undergoing CABG were studied in a myograph. The interaction between hU-II and various calcium antagonists or glyceryl trinitrate (GTN) was investigated in 2 ways: relaxing effect of vasodilators on the hU-II-induced precontraction and depressing effect of vasodilator agents on the contraction caused by hU-II (n=6 to 10 in each subgroup).

RESULTS

Human urotensin II caused contractile response in all human IMA. In potassium chloride-contraction, full (nifedipine: 99.1 %±2.7%) or nearly full (diltiazem: 93.5%±4.8%) relaxation with 30.9-fold higher potency to nifedipine than to diltiazem (EC50 [effective concentration causing 50% of maximal response] -8.24±0.21 vs -6.75±0.20 log M, p=0.0002) and in hU-II-contraction, nearly full relaxation (nifedipine: 90.6%±4.6%; diltiazem: 95.0%±1.7%) with 5.8-fold higher potency to nifedipine than to diltiazem (EC50 -7.55±0.26 vs -6.79±0.25 log M, p=0.03) were observed. The GTN caused nearly full relaxation (93.1%±4.8%) but GTN pretreatment had limited effect in prevention of the hU-II-induced contraction, whereas diltiazem and nifedipine reduced subsequent contraction to hU-II.

CONCLUSIONS

Human urotensin II is a potent vasoconstrictor in human IMA. Calcium antagonists and GTN relax the contraction caused by hU-II with different potencies. However, calcium antagonists are more effective than GTN in preventing the contraction induced by hU-II. These findings may have clinical implications in CABG.

Elevated plasma levels of urotensin II do not correlate with systemic haemodynamics in patients with cirrhosis

BACKGROUND

The hyperdynamic circulation of hepatic cirrhosis is related to decreased systemic vascular resistance due to arterial vasodilation. Urotensin II plasma levels are increased in cirrhotic patients, and have been suggested to play a role in the pathogenesis of systemic haemodynamic alterations.

AIM

To evaluate the relationships between systemic haemodynamics and urotensin II plasma levels.

METHODS

Thirty-six consecutive in-patients with cirrhosis and no alteration of plasma creatinine, and 20 age- and gender-matched healthy volunteers underwent noninvasive assessment of systemic haemodynamics and measurement of urotensin II plasma levels.

RESULTS

In comparison to healthy controls, cirrhotic patients had signs of hyperdynamic circulation and higher plasma urotensin II levels. Plasma urotensin II was neither significantly different amongst patients with different severity of cirrhosis nor between patients with or without ascites. Both in controls and cirrhotic patients no significant correlations were found between parameters of systemic haemodynamics and plasma urotensin II levels.

CONCLUSIONS

In patients with cirrhosis and hyperdynamic circulation, but with normal serum creatinine, urotensin II is higher than in healthy subjects. However, no correlation with cardiac index or other haemodynamic parameters was observed, indicating that other mechanisms prevail.

Urotensin II receptor antagonist attenuates monocrotaline-induced cardiac hypertrophy in rats

Urotensin II (UII) is a vasoactive peptide with potent cardiovascular effects through a G protein-coupled receptor. Hypoxia stimulates the secretion of UII and atrial natriuretic peptide (ANP). However, the effect of UII on hypoxia-induced cardiac hypertrophy is still controversial. The present study was conducted to determine whether human UII (hUII)-mediated ANP secretion influences hypoxia-induced cardiac hypertrophy using in vitro and in vivo models. Hypoxia caused an increase in ANP secretion and a decrease in atrial contractility in isolated perfused beating rat atria. hUII (0.01 and 0.1 nM) attenuated hypoxia-induced ANP secretion without changing the atrial contractility, and the hUII effect was mediated by the UII receptor signaling involving phospholipase C, inositol 1,3,4 trisphosphate receptor, and protein kinase C. Rats treated with monocrotaline (MCT, 60 mg/kg) showed right ventricular hypertrophy with increases in pulmonary arterial pressure and its diameter and plasma levels of UII and ANP that were attenuated by the pretreatment with an UII receptor antagonist, urantide. An acute administration of hUII (5 μM injection plus 2.5 μM infusion for 15 min) decreased the plasma ANP level in MCT-treated rats but increased the plasma ANP level in MCT plus urantide-treated and sham-operated rats. These results suggest that hUII may deteriorate MCT-induced cardiac hypertrophy mainly through a vasoconstriction of the pulmonary artery and partly through the suppression of ANP secretion.

Advances in understanding the role of the UII/UT system in the pathogenesis of portal hypertension

Urotensin II (UII), a vasoactive peptide with structural similarity to somatostatin, is the most potent vasoconstrictor known in systemic resistance vessels and has multiple biological effects related to a variety of human diseases. Numerous studies have found that UII and its receptor (UT) play an important role in the pathogenesis of portal hypertension. This paper reviews the recent advances in understanding the role of the UII/UT system in the pathogenesis of portal hypertension.

Role of urotensin II in health and disease

Urotensin II (UII) is an 11 amino acid cyclic peptide originally isolated from the goby fish. The amino acid sequence of UII is exceptionally conserved across most vertebrate taxa, sharing structural similarity to somatostatin. UII binds to a class of G protein-coupled receptor known as GPR14 or the urotensin receptor (UT). UII and its receptor, UT, are widely expressed throughout the cardiovascular, pulmonary, central nervous, renal, and metabolic systems. UII is generally agreed to be the most potent endogenous vasoconstrictor discovered to date. Its physiological mechanisms are similar in some ways to other potent mediators, such as endothelin-1. For example, both compounds elicit a strong vascular smooth muscle-dependent vasoconstriction via Ca2+ release. UII also exerts a wide range of actions in other systems, such as proliferation of vascular smooth muscle cells, fibroblasts, and cancer cells. It also 1) enhances foam cell formation, chemotaxis of inflammatory cells, and inotropic and hypertrophic effects on heart muscle; 2) inhibits insulin release, modulates glomerular filtration, and release of catecholamines; and 3) may help regulate food intake and the sleep cycle. Elevated plasma levels of UII and increased levels of UII and UT expression have been demonstrated in numerous diseased conditions, including hypertension, atherosclerosis, heart failure, pulmonary hypertension, diabetes, renal failure, and the metabolic syndrome. Indeed, some of these reports suggest that UII is a marker of disease activity. As such, the UT receptor is emerging as a promising target for therapeutic intervention. Here, a concise review is given on the vast physiologic and pathologic roles of UII.

Urotensin II induces migration of endothelial progenitor cells via activation of the RhoA/Rho kinase pathway

Urotensin II (UII) is a vasoactive peptide with many potent effects in the cardiorenovascular system and may be involved in the pathogenesis of atherosclerosis. Cardiovascular risk factors are often accompanied by reduced numbers of endothelial progenitor cells (EPCs) and their impaired migratory capacity. However, the role of UII in the migration of EPCs has not been reported so far. The aim of this study was to investigate whether UII influences the chemotactic function of bone marrow-derived EPCs and the possible signaling mechanisms involved. As a ligand for the orphan G-protein coupled receptor 14 (GPR14, UT receptor), UII exerts vasoactive functions through activation of the RhoA/Rho kinase pathway. We therefore analyzed the expression of GPR14 mRNA and protein, the activation of RhoA kinase and the phosphorylation of myosin light chain (MLC) in EPCs, isolated from the rat bone marrow. EPCs of 1-4 passages expressed GPR14 mRNA and protein. Chemotaxis assays were performed using Transwell cell-culture chambers with UII (10(-10)-10(-6) M), showing that UII induced chemotaxis of EPCs in a concentration-dependent manner after 3-h treatment (all p < 0.05), with the highest value (about 3-fold increase) at 10(-8) M. UII caused rapid activation of RhoA and increased phosphorylation of MLC. Conversely, a Rho-kinase inhibitor Y-27632 prevented the UII-induced migration and the phosphorylation of MLC. In conclusion, GPR14/UT receptor is expressed in EPCs, and UII induces migration of EPCs via activation of the RhoA/Rho kinase pathway. These findings provide new insights into the actions of UII in atherosclerosis.

Urotensin II stimulates high frequency-induced ANP secretion via PLC-PI 3K-PKC pathway

Urotensin II (U-II) and its receptor are coexpressed in the heart and show various cardiovascular functions. However, the relationship between U-II and cardiac hormone atrial natriuretic peptide (ANP) is still unknown. The aim of the present study is to test whether U-II affects ANP secretion using in vitro perfusion experiments and in vivo studies. Human U-II (hU-II) (10(-11), 5x10(-11), 10(-10), 5x10(-10)M) stimulated ANP secretion from isolated perfused rat atria paced with high frequency (6.0Hz). However, atrial contractility and translocation of extracellular fluid (ECF) did not change. An increase in ANP secretion by rat U-II was similar to that by hU-II; however, urotensin-related peptide showed no significant effect on ANP secretion. Pretreatment with urotensin receptor antagonist and inhibitor for phospholipase C (PLC), phosphoinositide 3-kinase (PI3K), or protein kinase C (PKC) attenuated hU-II-induced ANP secretion from atria paced with high frequency, but an inhibitor for inositol triphosphate did not. Intravenous infusion of hU-II at a dose of 2.5microM for 20min increased plasma ANP level, along with increased heart rate and pulse pressure in anesthetized rats. Therefore, we suggest that U-II stimulates high stimulation frequency-induced ANP secretion partly through the urotensin receptor and the PLC/PI3K/PKC pathway.

Acute neurohumoral modulation of diastolic function

Diastole plays a central role in cardiovascular homeostasis. Its two main determinants, myocardial relaxation and passive properties of the ventricular wall, are nowadays regarded as physiological mechanisms susceptible of active modulation. Furthermore, diastolic dysfunction and heart failure with normal ejection fraction (previously called diastolic heart failure) are two subjects of major clinical relevance and an intense area of research. The role of several neurohumoral mediators like angiotensin-II and endothelin-1 on the modulation of diastolic function was systematically described as having only chronic deleterious effects such as cardiac hypertrophy and fibrosis. However, over the last years a growing body of evidence described a new role for several peptides on the acute modulation of diastolic function. In the acute setting, some of these mediators may have the potential to induce an adaptive cardiac response. In this review, we describe the role of angiotensin-II, endothelin-1, nitric oxide, urotensin-II and ghrelin on the acute modulation of diastolic function, emphasizing its pathophysiological relevance. Only a thorough understanding of diastolic physiology as well as its active modulation, both in the acute and chronic settings, will improve our knowledge on diastolic dysfunction and allow us to solve the enigmas of heart failure with normal ejection fraction.

Urotensin II in cardiovascular regulation

Cardiovascular function is modulated by neuronal transmitters, circulating hormones, and factors that are released locally from tissues. Urotensin II (UII) is an 11 amino acid peptide that stimulates its' obligatory G protein coupled urotensin II receptors (UT) to modulate cardiovascular function in humans and in other animal species, and has been implicated in both vasculoprotective and vasculopathic effects. For example, tissue and circulating concentrations of UII have been reported to increase in some studies involving patients with atherosclerosis, heart failure, hypertension, preeclampsia, diabetes, renal disease and liver disease, raising the possibility that the UT receptor system is involved in the development and/or progression of these conditions. Consistent with this hypothesis, administration of UT receptor antagonists to animal models of cardiovascular disease have revealed improvements in cardiovascular remodelling and hemodynamics. However, recent studies have questioned this contributory role of UII in disease, and have instead postulated a protective effect on the cardiovascular system. For example, high concentrations of circulating UII correlated with improved clinical outcomes in patients with renal disease or myocardial infarction. The purpose of this review is to consider the regulation of the cardiovascular system by UII, giving consideration to methodologies for measurement of plasma concentrations, sites of synthesis and triggers for release.

Urotensin II: a new pharmacologic target in the treatment of cardiovascular disease

Urotensin II was first identified over 30 years ago as a potent vasoconstrictor, and the identification of its receptor in the heart, lungs, blood vessels, and brain have made it a potential target for human pharmacotherapy. Current research would suggest that urotensin II plays a major role in the pathophysiology of various cardiovascular disease entities. This article discusses the biologic effects of urotensin under normal and pathophysiologic conditions, and reviews the research experiences with synthetic urotensin blockers in the treatment of various cardiovascular illnesses.