Exercise urotensin II dynamics in myocardial infarction survivors with and without hypertension

Urotensin-II, oxidative stress, and inflammation increase in hypertensive and resistant hypertensive patients

Objective: Hypertension is a multi-factorial process prevalent in developed as well as in developing countries. Urotensin-II, different antioxidants, free radicals, and inflammatory biomarkers play an essential role in the cardiovascular system. The aim of this study is to investigate Urotensin-II, oxidative stress, and inflammation markers in normotensive, hypertensive, and resistant hypertensive patients. Methods: Fifty resistance hypertensive (rHT) patients, 50 hypertensive patients, and 50 age gender matched normotensive controls (NT-control) were enrolled. Urotensin-II (UII), total oxidant status (TOS), total antioxidant status (TAS), native thiol (NT), total thiol (TT), disulfide (DIS), interleukin 1 beta (IL1β), interleukin 6 (IL6), tumor necrosis factor-alpha (TNFα), high sensitive c reactive protein (hsCRP), high-density lipoprotein (HDL) low-density lipoprotein (LDL), and total cholesterol (TC) were evaluated. Results: Serum levels of UII, IL1β, IL6, TNFα, DIS, TOS, and OSI were found higher in rHT and HT as compared to NT-control (p < .001). On the contrary, serum levels of TT, TAS, and NT were lower in rHT and HT as compared to NT-control (p < .001). While TC, hsCRP, TOS, OSI, UII, IL1β, IL6, and TNFα levels increase from HT to rHT group (p < .001); TAS and NT levels decrease from HT to rHT group (p < .001). Conclusions: UII levels, oxidative stress, and inflammation are higher in rHT and HT, while antioxidants and thiol levels are lower than the NT-control. Our study clearly showed that rHT and HT are more susceptible to impaired states of antioxidants, oxidative stress, and free radicals.

Association between Plasma Urotensin II and Risk of Hypertension: Findings from a Prospective Study

Up to date, human urotensin II (UII) is the most potent vasoconstrictor in mammalian animals. To explore whether UII played an important role in the development of hypertension, we conducted a prospective study in Changshu city, China. The baseline investigation was carried out in 2007, and the first follow-up investigation was conducted in 2013. From the participants, we randomly obtained 2000 normotensive subjects aged 40 years and older without any severe disease at baseline and examined plasma UII and endothelin-1 (ET-1) with their blood samples at baseline. Logistic models were used to analyze the association between baseline UII, baseline ET-1, and newly occurring hypertension. In 1,819 subjects with complete data, 723 subjects developed into hypertensive in about five years. After adjusting some potential confounders, the odds ratio (95% confidence interval) for risk of hypertension comparing the highest with the lowest quartile of baseline UII was 0.888 (0.689–1.144). The role of UII in the development of hypertension was not found in the current study; therefore, further research studies should be conducted to explore the relationship between UII and hypertension.

Natural and synthetic peptides in the cardiovascular diseases: An update on diagnostic and therapeutic potentials

Several peptides play an important role in physiological and pathological conditions into the cardiovascular system. In addition to well-known vasoactive agents such as angiotensin II, endothelin, serotonin or natriuretic peptides, the vasoconstrictor Urotensin-II (Uro-II) and the vasodilators Urocortins (UCNs) and Adrenomedullin (AM) have been implicated in the control of vascular tone and blood pressure as well as in cardiovascular disease states including congestive heart failure, atherosclerosis, coronary artery disease, and pulmonary and systemic hypertension. Therefore these peptides, together with their receptors, become important therapeutic targets in cardiovascular diseases (CVDs). Circulating levels of these agents in the blood are markedly modified in patients with specific CVDs compared with those in healthy patients, becoming also potential biomarkers for these pathologies. This review will provide an overview of current knowledge about the physiological roles of Uro-II, UCN and AM in the cardiovascular system and their implications in cardiovascular diseases. It will further focus on the structural modifications carried out on original peptide sequences in the search of analogues with improved physiochemical properties as well as in the delivery methods. Finally, we have overviewed the possible application of these peptides and/or their precursors as biomarkers of CVDs.

International Union of Basic and Clinical Pharmacology. XCII. Urotensin II, urotensin II-related peptide, and their receptor: from structure to function

Urotensin II (UII) is a cyclic neuropeptide that was first isolated from the urophysis of teleost fish on the basis of its ability to contract the hindgut. Subsequently, UII was characterized in tetrapods including humans. Phylogenetic studies and synteny analysis indicate that UII and its paralogous peptide urotensin II-related peptide (URP) belong to the somatostatin/cortistatin superfamily. In mammals, the UII and URP genes are primarily expressed in cholinergic neurons of the brainstem and spinal cord. UII and URP mRNAs are also present in various organs notably in the cardiovascular, renal, and endocrine systems. UII and URP activate a common G protein-coupled receptor, called UT, that exhibits relatively high sequence identity with somatostatin, opioid, and galanin receptors. The UT gene is widely expressed in the central nervous system (CNS) and in peripheral tissues including the retina, heart, vascular bed, lung, kidney, adrenal medulla, and skeletal muscle. Structure-activity relationship studies and NMR conformational analysis have led to the rational design of a number of peptidic and nonpeptidic UT agonists and antagonists. Consistent with the wide distribution of UT, UII has now been shown to exert a large array of biologic activities, in particular in the CNS, the cardiovascular system, and the kidney. Here, we review the current knowledge concerning the pleiotropic actions of UII and discusses the possible use of antagonists for future therapeutic applications.

Association between human urotensin II and essential hypertension--a 1:1 matched case-control study

Objective

We aimed to evaluate the controversial association between human urotensin II and essential hypertension in untreated hypertensive cases and normotensive controls.

Methods

197 newly diagnosed hypertensive patients and 197 age- and sex-matched normotensive controls were studied. Plasma urotensin II, nitric oxide metabolites, and other traditional biomarkers were examined.

Results

Hypertensive patients had higher urotensin II [median (interquartile rang): 9.32 (7.86–11.52) ng/mL vs 8.52 (7.07–10.41) ng/mL] and lower nitric oxide metabolites [19.19 (2.55–38.48) µmol/L vs 23.83 (11.97–43.40) µmol/L] than normotensive controls. Urotensin II was positively correlated with systolic blood pressure (r = 0.169, P<0.001) and diastolic blood pressure (r = 0.113, P = 0.024) while negatively correlated with nitric oxide metabolites (r = −0.112, P = 0.027). In multivariate regression analysis, subjects in the highest quartile of urotensin II were more likely to have hypertension than those in the lowest quartile (OR, 2.58; 95% CI, 1.21–5.49). Sub-group analyses in 106 pairs of cases and controls with either both normal or both abnormal nitric oxide metabolites levels showed that the association between urotensin II levels and hypertension persisted (P value for trend = 0.039).

Conclusion

Human urotensin II is markedly associated with essential hypertension, and the association is independent of nitric oxide metabolites. Our results indicated that urotensin II might be an independent risk factor for essential hypertension.

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.

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.

Palosuran inhibits binding to primate UT receptors in cell membranes but demonstrates differential activity in intact cells and vascular tissues

BACKGROUND AND PURPOSE

The recent development of the UT ligand palosuran (1-[2-(4-benzyl-4-hydroxy-piperidin-1-yl)-ethyl]-3-(2-methyl-quinolin-4-yl)-urea sulphate salt) has led to the proposition that urotensin-II (U-II) plays a significant pathological role in acute and chronic renal injury in the rat.

EXPERIMENTAL APPROACH

In the present study, the pharmacological properties of palosuran were investigated further using a series of radioligand binding and functional bioassays.

KEY RESULTS

Palosuran functioned as a 'primate-selective' UT ligand in recombinant cell membranes (monkey and human UT K(i) values of 4 +/- 1 and 5 +/- 1 nM), lacking appreciable affinity at other mammalian UT isoforms (rodent and feline K(i) values >1 microM). Paradoxically, however, palosuran lost significant (10- to 54-fold) affinity for native and recombinant human UT when radioligand binding was performed in intact cells (K(i) values of 50 +/- 3 and 276 +/- 67 nM). In accordance, palosuran also exhibited diminished activity in hUT (human urotensin-II receptor)-CHO (Chinese hamster ovary) cells (IC50 323 +/- 67 nM) and isolated arteries (K(b)>10 microM in rat aorta; K(b)>8.5 microM in cat arteries; K(b)>1.6 microM in monkey arteries; K(b) 2.2 +/- 0.6 microM in hUT transgenic mouse aorta). Relative to recombinant binding K(i) values, palosuran was subjected to a 392- to 690-fold reduction in functional activity in monkey isolated arteries. Such phenomena were peculiar to palosuran and were not apparent with an alternative chemotype, SB-657510 (2-bromo-N-[4-chloro-3-((R)-1-methyl-pyrrolidin-3-yloxy)-phenyl]-4,5-dimethoxybenzenesulphonamide HCl).

CONCLUSIONS AND IMPLICATIONS

Collectively, such findings suggest that caution should be taken when interpreting data generated using palosuran. The loss of UT affinity/activity observed in intact cells and tissues cf. membranes offers a potential explanation for the disappointing clinical efficacy reported with palosuran in diabetic nephropathy patients. As such, the (patho)physiological significance of U-II in diabetic renal dysfunction remains uncertain.

The role of urotensin II in the metabolic syndrome

Urotensin II is a potent vasoconstrictive peptide that mediates both endothelium-independent vasoconstriction and endothelium-dependent vasodilatation. Its plasma level correlates positively with body weight and is raised in diabetes, renal failure, hypertension, and other cardiovascular diseases including congestive heart failure and carotid atherosclerosis. It can inhibit glucose-induced insulin secretion, and genetic variants in urotensin II gene are associated with insulin resistance and type 2 diabetes. Urotensin II also affects lipid metabolism in fish and food intake in mice. Recent studies have also demonstrated a role of urotensin II in inflammation and endothelial dysfunction. These findings suggest a close relationship between urotensin II and at least some components of the metabolic syndrome, including hypertension, insulin resistance, hyperglycemia, and inflammation.

Urotensin-II and cardiovascular diseases

Urotensin-II (U-II) is a vasoactive factor with pleiotropic effects. U-II exerts its activity by binding to a G-protein-coupled receptor termed UT. U-II and its receptor are highly expressed in the cardiovascular system. Increased U-II plasma levels have been reported in patients with cardiovascular disease of varying etiologies. We and others have shown that U-II and UT expression is elevated in both clinical and experimental heart failure and atherosclerosis. U-II induces cardiac fibrosis by increasing fibroblast collagen synthesis. In addition, U-II induces cardiomyocyte hypertrophy and increased vascular smooth muscle cell proliferation. We have shown that U-II antagonism using a selective U-II blocker, SB-611812 reduces neointimal thickening and increases lumen diameter in a rat restenosis model of carotid artery angioplasty. These findings suggest an important role for U-II in cardiovascular dysfunction and remodeling.

Human urotensin II as a link between hypertension and coronary artery disease

Hypertension is a well-known risk factor for atherosclerosis, but the molecular mechanisms that link elevated blood pressure to the progression of atherosclerosis remain unclear. Human urotensin II (U-II), the most potent endogenous vasoconstrictor peptide identified to date, and its receptor (UT receptor) are involved in the etiology of essential hypertension. In patients with essential hypertension, U-II infused into the forearm brachial artery has been shown to induce vasoconstriction. Recent studies have demonstrated elevated plasma U-II concentrations in patients with essential hypertension, diabetes mellitus, atherosclerosis, and coronary artery disease. U-II is expressed in endothelial cells, macrophages, macrophage-derived foam cells, and myointimal and medial vascular smooth muscle cells (VSMCs) of atherosclerotic human coronary arteries. UT receptors are present in VSMCs of human coronary arteries, the thoracic aorta and cardiac myocytes. Lymphocytes are the most active producers of U-II, whereas monocytes and macrophages are the major cell types expressing UT receptors, with relatively little receptor expression in foam cells, lymphocytes, and platelets. U-II accelerates foam cell formation by up-regulation of acyl-coenzyme A:cholesterol acyltransferase-1 in human monocyte-derived macrophages. In human endothelial cells, U-II promotes cell proliferation and up-regulates type 1 collagen expression. U-II also activates nicotinamide adenine dinucleotide phosphate (NADPH) oxidase and plasminogen activator inhibitor-1 in human VSMCs, and stimulates VSMC proliferation with synergistic effects observed when combined with oxidized low-density lipoprotein, lysophosphatidylcholine, reactive oxygen species or serotonin. These findings suggest that U-II plays key roles in accelerating the development of atherosclerosis, thereby leading to coronary artery disease.