Expression of endothelin-converting enzyme, endothelin-1 and endothelin receptors at the site of percutaneous coronary intervention in humans

Association of Endothelin-Converting Enzyme and Endothelin-1 Gene Polymorphisms with Essential Hypertension in Malay Ethnics

Objectives

Endothelin-1 (ET-1), the most potent endogenous vasoconstrictor, generated by enzymatic cleavage catalyzed by an endothelin-converting enzyme (ECE), plays a significant role in the regulation of hypertension.

Methods

This study investigates the effect of endothelin-1 (Lys198Asn/rs5370) and ECE (rs212526 C/T) gene polymorphisms with essential hypertension (EH) among Malay ethnics. To determine the association of gene polymorphism, 177 hypertensives and controls (196) were genotyped using Taqman method.

Results

A significant difference was observed in ET-1 rs5370 and ECE rs212526 gene polymorphisms between EH and control subjects (P < 0.001). A significantly high body mass index (BMI), waist-to-hip ratio, fasting plasma glucose, hemoglobin A1c, systolic and diastolic blood pressure, and lipid profiles were observed among the EH patients when compared to controls (P < 0.05). Moreover, T allele (rs5370) carriers in males have a high risk for EH. There was no significant association between gender in ECE C/T polymorphisms (P > 0.05).

Conclusion

Based on our result, it is evident that the T allele of ET-1 rs5370 polymorphism and C allele of ECE rs212526 have a significant genetic risk factor in EH among Malay subjects, and BMI and age are associated with hypertension.

Association of ECE1 gene polymorphisms and essential hypertension risk in the Northern Han Chinese: A case-control study

Background

The ECE1 gene polymorphisms have been studied as a candidate gene in essential hypertension, but no consensus has been reached. To systematically explore their possible association, a case‒control study was conducted.

Methods

This study included 398 hypertensive subjects and 596 healthy volunteers as control subjects in the Northern Han Chinese. A total of 10 tag SNPs of ECE1 gene were genotyped successfully by TaqMan assay.

Results

A total of 10 SNPs (rs212544, rs2076280, rs115071, rs2076283, rs9426748, rs11590928, rs212515, rs2236847, rs2282715, and rs2774028) were identified as the tag SNPs for ECE1 gene. Although no positive connection has been found in general population, several SNPs have been found to be related to EH risk in gender‐stratified subgroup analysis. In males, rs115071 T allele influenced EH risk in a protective manner, with dominant model (TT+TC vs. CC: p = .032, OR = 0.655, 95% CI = 0.445–0.965), additive model (TT vs. TC vs. CC: p = .019, OR = 0.616, 95% CI = 0.411–0.924), as well as allele comparison (T vs. C: p = .045, OR = 0.702, 95% CI = 0.496–0.992). While, in females, rs212544 AA genotype would increase the onset risk of EH (recessive model: AA vs. GA+GG, p = .024, OR = 1.847, 95% CI = 1.086–3.142). In the three haplotype blocks identified, rs2076283‐rs2236847 C‐T haplotype was associated with a decreased risk of EH (OR = 0.558, p = .046).

Conclusion

The current case‒control study suggested that several SNPs and related haplotypes on ECE1 gene might be associated with the susceptibility of EH in certain gender subgroups in the Northern Han Chinese population.

Neointimal coverage after second generation drug-eluting stent implantation has a relationship with pre-existing atherosclerotic lesion characteristics

The relationship between preexisting atherosclerotic lesion characteristics and neointimal thickness after second-generation drug-eluting stent (DES) placement is still unknown. Thus, we evaluated that relationship using optical coherence tomography (OCT).A single-center, retrospective, observational study was conducted. Patients with stable angina or asymptomatic myocardial ischemia who received percutaneous coronary intervention for a de novo lesion using a second-generation DES under frequency domain OCT guidance and underwent follow-up coronary angiography (CAG) and OCT between December 2010 and December 2015 were included. The relationship between the neointimal thickness on the stent strut and the plaque characteristics was retrospectively evaluated using OCT immediately after stent implantation and at the time of follow-up CAG.We analyzed 3459 struts from 20 stents in 15 patients. The mean follow-up period was 264 days. In the follow-up study, no angiographic in-stent restenosis was found. Of the 3459 struts, 3315 (95.8%) were covered with neointima. The median neointimal thicknesses of the stent struts on calcified, fibrous, and lipid-rich lesions were 20 μm (interquartile range [IQR], 10-50 μm), 70 μm (40-140 μm; P < .001), and 90 μm (50-170 μm; P < .001), respectively. These differences were observed regardless of the type of second-generation DES used.Most of the stent struts were covered with neointima. The neointimal thickness after the second-generation DES implantation had a close relationship with the preexisting atherosclerotic lesion characteristics. In this study, we found differences in arterial healing processes due to underlying plaque; therefore, evaluating the lesion characteristics by OCT may predict the risk for future restenosis and thrombosis.

Neopterin and Cardiovascular Events Following Coronary Stent Implantation in Patients with Stable Angina Pectoris

AIM

Neopterin is an activation marker for monocytes/macrophages. We prospectively investigated the predictive value of plasma neopterin levels on 2-year and long-term cardiovascular events in patients with stable angina pectoris (SAP) undergoing coronary stent implantation.

METHODS

We studied 123 consecutive patients with SAP who underwent primary coronary stenting (44 patients with bare metal stent: BMS group and 79 with drug-eluting stent: DES group). Plasma neopterin levels were measured on admission using HPLC. Moreover, one frozen coronary artery specimen after DES and three frozen coronary specimens after BMS were obtained by autopsy or endarterectomy, followed by immunohistochemical staining for neopterin.

RESULTS

Plasma neopterin levels were significantly higher in patients with cardiovascular events than in those without them (P＜0.001). In subgroup analyses, higher levels of plasma neopterin in patients with cardiovascular events (P＜0.001) and a positive correlation between neopterin levels and late lumen loss after stenting (P =0.008) were observed in the BMS group but not in the DES group (P=0.53 and P=0.17, respectively). In long-term cardiovascular events, multivariate Cox regression analysis identified the significance of the high-neopterin group as independent determinants of cardiovascular events (hazard ratio, 2.225; 95% CI, 1.283-3.857; P =0.004). Immunohistochemical staining showed abundant neopterin-positive macrophages in the neointima after BMS implantation but no neopterin-positive macrophages in the neointima after DES implantation.

CONCLUSION

These findings suggest that neopterin is associated with cardiovascular events after coronary stent implantation in patients with SAP. However, there might be a strong association between neopterin and cardiovascular events after BMS but not after DES in these patients.

Endothelial dysfunction and vascular disease - a 30th anniversary update

The endothelium can evoke relaxations of the underlying vascular smooth muscle, by releasing vasodilator substances. The best-characterized endothelium-derived relaxing factor (EDRF) is nitric oxide (NO) which activates soluble guanylyl cyclase in the vascular smooth muscle cells, with the production of cyclic guanosine monophosphate (cGMP) initiating relaxation. The endothelial cells also evoke hyperpolarization of the cell membrane of vascular smooth muscle (endothelium-dependent hyperpolarizations, EDH-mediated responses). As regards the latter, hydrogen peroxide (H₂ O₂ ) now appears to play a dominant role. Endothelium-dependent relaxations involve both pertussis toxin-sensitive G_i (e.g. responses to α₂ -adrenergic agonists, serotonin, and thrombin) and pertussis toxin-insensitive G_q (e.g. adenosine diphosphate and bradykinin) coupling proteins. New stimulators (e.g. insulin, adiponectin) of the release of EDRFs have emerged. In recent years, evidence has also accumulated, confirming that the release of NO by the endothelial cell can chronically be upregulated (e.g. by oestrogens, exercise and dietary factors) and downregulated (e.g. oxidative stress, smoking, pollution and oxidized low-density lipoproteins) and that it is reduced with ageing and in the course of vascular disease (e.g. diabetes and hypertension). Arteries covered with regenerated endothelium (e.g. following angioplasty) selectively lose the pertussis toxin-sensitive pathway for NO release which favours vasospasm, thrombosis, penetration of macrophages, cellular growth and the inflammatory reaction leading to atherosclerosis. In addition to the release of NO (and EDH, in particular those due to H₂ O₂ ), endothelial cells also can evoke contraction of the underlying vascular smooth muscle cells by releasing endothelium-derived contracting factors. Recent evidence confirms that most endothelium-dependent acute increases in contractile force are due to the formation of vasoconstrictor prostanoids (endoperoxides and prostacyclin) which activate TP receptors of the vascular smooth muscle cells and that prostacyclin plays a key role in such responses. Endothelium-dependent contractions are exacerbated when the production of nitric oxide is impaired (e.g. by oxidative stress, ageing, spontaneous hypertension and diabetes). They contribute to the blunting of endothelium-dependent vasodilatations in aged subjects and essential hypertensive and diabetic patients. In addition, recent data confirm that the release of endothelin-1 can contribute to endothelial dysfunction and that the peptide appears to be an important contributor to vascular dysfunction. Finally, it has become clear that nitric oxide itself, under certain conditions (e.g. hypoxia), can cause biased activation of soluble guanylyl cyclase leading to the production of cyclic inosine monophosphate (cIMP) rather than cGMP and hence causes contraction rather than relaxation of the underlying vascular smooth muscle.

Plasma endothelin-1 level as a predictor for poor collaterals in patients with ≥95% coronary chronic occlusion

BACKGROUND

Coronary collateral circulation (CCC) plays an important role in protecting myocardium from ischemic damage. The studies on factors which impact on CCC might be of great clinical interest. The aim of the present study was to evaluate endothelin-1 (ET-1) as a potential predictor for poor or good CCC in patients with angiography-proven ≥95% coronary occlusion.

METHODS

We screened 1038 consecutive patients with ≥95% occlusion in at least one major epicardial coronary artery detected by coronary angiography. Of these, 663 patients were classified into the poor CCC group with Rentrop 0-2 grade collateral circulation and 375 patients into the good CCC group with Rentrop 3 grade. The association of plasma ET-1 levels with collateral status was assessed.

RESULTS

We found that patients in the poor CCC group had a higher ET-1 level than those in the good CCC group (0.59±0.48 vs. 0.39±0.32pmol/L, p<0.001), and the ET-1 values increased with the descent of the Rentrop grades (p for trend<0.001). Moreover, multivariate logistic regression analysis revealed an independent association between ET-1 and collateral status (odds ratio [95% CI] for poor CCC 2.27 [1.60-3.22], p<0.001). Additionally, the association presented significance in both men (odds ratio [95% CI] for poor CCC 3.18 [2.20-4.74], p<0.001) and women (odds ratio [95% CI] for poor CCC 3.10 [1.36-7.85], p=0.011) when the sex-specific analysis was performed.

CONCLUSIONS

Plasma ET-1 level may be a useful, easily available marker for predicting the degree of CCC in patients with ≥95% coronary chronic occlusion.

Selective endothelin A receptor antagonism with sitaxentan reduces neointimal lesion size in a mouse model of intraluminal injury

BACKGROUND AND PURPOSE

Endothelin (ET) receptor antagonism reduces neointimal lesion formation in animal models. This investigation addressed the hypothesis that the selective ETA receptor antagonist sitaxentan would be more effective than mixed ETA / B receptor antagonism at inhibiting neointimal proliferation in a mouse model of intraluminal injury.

EXPERIMENTAL APPROACH

Antagonism of ETA receptors by sitaxentan (1-100 nM) was assessed in femoral arteries isolated from adult, male C57Bl6 mice using isometric wire myography. Neointimal lesion development was induced by intraluminal injury in mice receiving sitaxentan (ETA antagonist; 15 mg·kg(-1) ·day(-1) ), A192621 (ETB antagonist; 30 mg·kg(-1) ·day(-1) ), the combination of both antagonists or vehicle. Treatment began 1 week before, and continued for 28 days after, surgery. Femoral arteries were then harvested for analysis of lesion size and composition.

KEY RESULTS

Sitaxentan produced a selective, concentration-dependent parallel rightward shift of ET-1-mediated contraction in isolated femoral arteries. Sitaxentan reduced neointimal lesion size, whereas ETB and combined ETA / B receptor antagonism did not. Macrophage and α-smooth muscle actin content were unaltered by ET receptor antagonism but sitaxentan reduced the amount of collagen in lesions.

CONCLUSIONS AND IMPLICATIONS

These results suggest that ETA receptor antagonism would be more effective than combined ETA /ETB receptor antagonism at reducing neointimal lesion formation.

Polymorphisms of ECE1 may contribute to susceptibility to ischemic stroke in Han Chinese of Northern China

Endothelin (ET) converting enzyme 1 (ECE1) is well known for its critical role in the process of ET. Recent studies have demonstrated that two genetic variants of ECE1 gene, rs212528 and rs213045 (C338A), are associated with hypertension and atherosclerosis formation. To investigate the association between the ECE1 gene polymorphisms and ischemic stroke (IS) in Chinese population. With a candidate loci strategy, we conducted a case-control study involving 381 IS cases and 366 non-IS controls in Han population of the Northern China. Two single nucleotide polymorphisms of ECE1 were genotyped and assessed the association with the risk of IS. Furthermore, stratified analyses were also carried out to evaluate the association between the gender or two etiologic subtypes [small-artery occlusion (SAO) and large-artery atherosclerosis (LAA)] and IS. Compared with rs213045 G homozygote, rs213045 TG genotype and rs213045 TT/TG genotypes are in dominant model significantly increased the risk of IS [adjusted odds ratio (OR) = 1.47, 95 % confidence interval (CI) = 1.04-2.07, P = 0.03; adjusted OR = 1.43, 95 % CI = 1.04-1.99, P = 0.029, respectively]. However, we did not find the significant association between the ECE1 gene polymorphisms and SAO or LAA of IS in this study. Our results indicated that ECE1 gene polymorphisms may contribute to the susceptibility of IS in Han population of the Northern China.

The significance of circulating endothelin-1 as a predictor of coronary artery disease status and clinical outcomes following coronary artery catheterization

BACKGROUND/OBJECTIVES

Coronary artery disease (CAD) is responsible for significant morbidity and mortality. Inflammatory, pro-thrombotic and structural factors contribute to the etiology of CAD. This study sought to determine the relationship of plasma endothelin-1 (pET-1), a potent vasoconstrictor, mitogen and modulator of cardiac inflammation, to clinical characteristics and outcomes of CAD patients.

METHODS

Blood samples were collected from 336 patients with underlying chest pain or recent myocardial infarction (MI), prior to coronary catheterization. pET-1 was correlated with clinical characteristics and outcomes following catheterization and at 30-day follow-up.

RESULTS

pET-1 was higher in recent MI patients than in patients with CAD (coronary occlusion≥50%) or without CAD (<50%) (Mean±sem (pg/ml): 2.12±0.13, 1.51±0.10, 1.21±0.06; 95% confidence interval (1.85-2.38, 1.31-1.72, 1.07-1.32; respectively, P<.0001). Patients with ST elevation MI (STEMI) had higher pET-1 than non-STEMI (P=.008). pET-1 was associated with heart failure (HF) and low left ventricular ejection fraction (LVEF) and was highest in MI patients presented with acute HF. At 30-day follow up, pET-1 was not associated with the change in LVEF. In multivariate analysis, pET-1 was positively associated with age, smoking, HF, CAD status, and need for revascularization by coronary artery bypass surgery (CABG). pET-1 was negatively correlated with LVEF and preoperative statin use.

CONCLUSIONS

pET-1 is associated with recent MI, HF, age, smoking, CABG, and low LVEF. Preoperative statin use was associated with lower pET-1. pET-1 may serve as a risk marker and a potential therapeutic target in CAD patients.

Aspirate from human stented native coronary arteries vs. saphenous vein grafts: more endothelin but less particulate debris

Stent implantation into atherosclerotic coronary arteries releases particulate debris and soluble substances that contribute to impaired microvascular perfusion. Here we addressed the potential for microvascular obstruction in patients with stenotic native right coronary arteries (nRCA) compared with saphenous vein grafts on right coronary arteries (SVG-RCA). We enrolled symptomatic, male patients with stable angina pectoris and a flow-limiting stenosis in their nRCA or SVG-RCA ( n = 18/18). Plaque volume and composition were analyzed using intravascular ultrasound before stent implantation. Coronary aspirate was retrieved during stent implantation under protection with a distal occlusion/aspiration device and divided into particulate debris and plasma. The release of catecholamines, endothelin, serotonin, thromboxane B2, and tumor necrosis factor-α was measured. The response of rat mesenteric arteries with intact (+E) and denuded (−E) endothelium to aspirate plasma (without and with selective endothelin receptor blockade) was normalized to that by potassium chloride (KClmax = 100%). Plaque volume and composition were not different between nRCA and SVG-RCA. There was less particulate debris (65 ± 8 vs. 146 ± 23 mg; P < 0.05) and more endothelin release (5.8 ± 0.8 vs. 1.3 ± 0.7 pg/ml; P < 0.05) in nRCA than in SVG-RCA, whereas the release of the other mediators was not different. Aspirate from nRCA induced stronger vasoconstriction than that from SVG-RCA [nRCA, 78 ± 6% (+E)/84 ± 5% (−E); SVG-RCA, 59 ± 6% (+E)/68 ± 3% (−E); P < 0.05 nRCA vs. SVG-RCA], which was attenuated by a nonspecific endothelin and a specific endothelin receptor A antagonist. Thus coronary aspirate from stented nRCA is characterized by less debris but more endothelin and stronger vasoconstrictor response than that from SVG-RCA.

Pathological Importance of the Endothelin-1/ET(B) Receptor System on Vascular Diseases

Activation of the endothelin (ET)-1/ET receptor system is involved in the development of vascular diseases such as atherosclerosis, vascular hypertrophy, and restenosis. Some issues still remain unresolved including whether ET receptor antagonists are expected to become the new therapeutic tools for the treatment of vascular diseases. One of the unresolved critical points is the functional role of ET receptor subtypes on each vascular disease, in particular the pathophysiological roles of the ET_B receptor. We recently demonstrated that selective inhibition of the ET_B receptor system showed harmful effects in the development of neointimal formation after vascular injury. However, there was no apparent difference in the therapeutic effects between a nonselective ET_A/ET_B receptor antagonist and selective ET_A receptor antagonist. These findings indicate that antagonism of the ET_A receptor system is essential for suppressing vascular remodeling, irrespective of the presence of ET_B-receptor-mediated actions, although the selective ET_B receptor antagonist worsens vascular remodeling. In addition, we found that ET receptor systems contribute to sex differences in the severity of vascular disease, thereby suggesting that the efficacy of ET receptor antagonists for vascular diseases may differ between sexes. In this paper, we outline the roles of the ET-1/ET_B receptor system on vascular diseases and its sex differences.

Pathophysiological roles of endothelin receptors in cardiovascular diseases

Endothelin (ET)-1 derived from endothelial cells has a much more important role in cardiovascular system regulation than the ET-2 and ET-3 isoforms. Numerous lines of evidence indicate that ET-1 possesses a number of biological activities leading to cardiovascular diseases (CVD) including hypertension and atherosclerosis. Physiological and pathophysiological responses to ET-1 in various tissues are mediated by interactions with ET(A)- and ET(B)-receptor subtypes. Both subtypes on vascular smooth muscle cells mediate vasoconstriction, whereas the ET(B)-receptor subtype on endothelial cells contributes to vasodilatation and ET-1 clearance. Although selective ET(A)- or nonselective ET(A)/ET(B)-receptor antagonisms have been assumed as potential strategies for the treatment of several CVD based on clinical and animal experiments, it remains unclear which antagonisms are suitable for individuals with CVD because upregulation of the nitric oxide system via the ET(B) receptor is responsible for vasoprotective effects such as vasodilatation and anti-cell proliferation. In this review, we have summarized the current understanding regarding the role of ET receptors, especially the ET(B) receptor, in CVD.

[Pathology of AtheroThrombosIS (ATIS)]

Once atherosclerosis develops, stenosis (or occlusion) may occur in the lumen of various arteries of the living body. This can lead to a range of conditions, including myocardial infarction, cerebral infarction, aortic aneurysm and peripheral artery disease. The acronym 'ATIS' (AtheroThrombosIS) is a collective term for diseases characterized by a common course of development based on atherosclerosis. This article reviews pathological findings in atherothrombotic lesions of human coronary, carotid, and vertebrobasilar arteries as well as leg arteries and veins. Histologically, atheromatous plaques of coronary arteries can broadly be typed as fibrous and lipid-rich (atheromatous). Macroscopically, fibrous plaque has a whitish appearance and is composed of smooth muscle cells and collagen fibres. Lipid-rich (atheromatous) plaque, on the other hand, appears yellow macroscopically, with the superficial layer (closer to the lumen) having a white fibrous cap which covers the atheroma. This fibrous cap is quite thin and is likely to rupture. Typical pathological features of such atherothrombosis are narrowing of the vascular lumen due to lipid-rich (atheromatous) plaque, and thrombus formation due to a broken fibrous cap. Such plaque rupture is the underlying cause of acute myocardial infarction in about 70% of patients, while acute myocardial infarction in the remaining patients (30%) results from plaque erosion. In cases of plaque erosion, atheroma is seldom seen, and atherosclerosis manifests in a full-circumferential manner, resulting in thrombus formation due to endothelial cell injury and eventually leading to obstructive thrombi. Thus, thrombus formation associated with myocardial infarction is attributable to plaque rupture if the lesion contains a lipid-rich (atheromatous) plaque. In cases where plaques cause particularly intense injury of endothelial cells, plaque erosion is likely to occur, resulting in formation of obstructive thrombi within the vascular lumen. Primary factors involved in the evolution of ATIS are injury of vascular endothelial cells, inflammation of a vulnerable plaque and intra-plaque haemorrhage. ATIS in other vascular systems has similar pathological features. The continued increase in the aged population and the morbidity of lifestyle-related diseases will make more cases of ATIS intractable. It will be of paramount importance to prevent intractable ATIS in the future.

Inhibition of endothelin ETB receptor system aggravates neointimal hyperplasia after balloon injury of rat carotid artery

Endothelin-1 (ET)/ET(A) receptor system has been known to play an important role in the pathogenesis of neointimal hyperplasia after endothelial injury. However, the pathological role of endothelin ET(B) receptors on neointimal hyperplasia remains to be elucidated. In the present study, we investigated the pathological role of ET(B) receptors on neointimal hyperplasia in balloon-injured rat carotid arteries by pharmacological blockade with use of 2R-(4-propoxyphenyl)-4S-(1,3-benzodioxol-5-yl)-1-(N-(2,6-diethylphenyl)aminocarbonyl-methyl)-pyrrolidine-3R-carboxylic acid (A-192621), a selective ET(B) receptor antagonist, 2R-(4-methoxyphenyl)-4S-(1,3-benzodioxol-5-yl)-1-(N,N-di(n-butyl)aminocarbonyl-methyl)-pyrrolidine-3R-carboxylic acid (ABT-627), a selective ET(A) receptor antagonist, and (+)-(5S,6R,7R)-2-butyl-7-[2-((2S)-2-carboxypropyl)-4-methoxyphenyl]-5-(3,4-methylenedioxyphenyl)cyclopenteno[1,2-b]pyridine-6-carboxylic acid (J-104132), an ET(A)/ET(B) dual receptor antagonist. Moreover, the spotting-lethal rats, which carry a naturally occurring deletion in the endothelin ET(B) receptor gene, were used to examine the effects of genetic deficiency for this receptor subtype. Two weeks after balloon injury, the ratio of the neointimal to the medial area (neointima/media ratio) was determined. Treatment with A-192621 (30 mg/kg/day) for 2 weeks after injury significantly increased the neointima/media ratio in the injured artery. In contrast, ABT-627 (10 mg/kg/day) and J-104132 (10 mg/kg/day) markedly decreased the neointima/media ratio to the same extent. Furthermore, the neointima/media ratio in the injured artery of the ET(B)-deficient rat was significantly increased compared with that of the wild-type rat, and this increase was abolished by treatment with J-104132. These findings suggest that the inhibition of the ET(B) receptor system leads to an aggravation of neointimal hyperplasia after balloon injury, and the augmentation of ET(A)-mediated actions are responsible for the neointimal hyperplasia aggravated by the pharmacological blockade of ET(B) receptor or by its genetic deficiency. The antagonism of the ET(A) receptor system is essential for preventing restenosis after angioplasty.

Enhanced expressions of endothelin-converting enzyme and endothelin receptors in human colonic tissues of Crohn's disease

Endothelin-1, a powerful vasoconstrictor, forms the endothelin system together with endothelin-converting enzyme and endothelin type A and type B receptors. These endothelin system components are considered to participate in inflammatory and wound healing responses. Previous reports have suggested a role for the endothelin-1 in the pathology of Crohn's disease. In the present study, we immunohistochemically investigated the expressions of the endothelin system components in affected human intestinal tissues of Crohn's disease. Eighteen surgical specimens of colonic tissue obtained from patients with Crohn's disease and 12 normal colonic tissues as controls were examined. Frozen tissue sections cut from the samples were subjected to the immunohistochemical single and double staining. The endothelin system components were expressed mainly in the muscular layers and blood vessels. In diseased colonic tissues, inflammatory infiltration and fibrotic tissue reactions with marked smooth muscle cell proliferation were frequently seen, and were closely associated with increased expressions of the endothelin system components. These results strongly suggest that endothelin-converting enzyme and endothelin type A and type B receptors collectively play a role in the inflammatory and fibrogenic processes of Crohn's disease. Especially, submucosal smooth muscle proliferation, a histological hallmark of strictures, may be attributable to the upregulated endothelin system.

Endothelin-converting enzyme-1b C-338A polymorphism is associated with the increased risk of coronary artery disease in Chinese population

BACKGROUND

Endothelin-converting enzyme-1 (ECE-1), the key enzyme responsible for endothelin-1 generation, has been linked to coronary artery disease (CAD). Recently, a genetic polymorphism (ECE-1b C-338A) located in ECE-1 gene promoter was identified. However, it is unclear whether this polymorphism is associated with the risk of CAD.

METHODS

We conducted a study with CAD patients and controls matched by age and sex to examine the prevalence of ECE-1b C-338A polymorphism in CAD.

RESULTS

The frequencies of ECE-1b-338CC, CA, and AA genotypes in cases (40.1%, 42.2%, and 17.7%) were significantly different from those of controls (50.6%, 40.5%, and 8.9%, chi2=9.989, P=0.007). Subjects with the variant genotypes (CA+ AA) had a 58% increased risk of CAD relative to CC carriers (adjusted OR=1.58, 95% CI=1.07-2.32). Furthermore, the adjusted OR of AA genotype for CAD was 2.33 (95% CI=1.25-4.35). In stratified analyses, the A allele was significantly associated with increased risk of CAD in female (adjusted OR=2.86, 95% CI=1.40-5.84) and subjects with age >or= 64 y (adjusted OR=2.96, 95% CI=1.73-5.08). Moreover, the frequency of patients with variant genotypes increased gradually from single- to triple-vessel disease although without statistical significance (P=0.069 for trend).

CONCLUSION

Our results suggested that ECE-1b-338C to A variant might be associated with increased risk of CAD in Chinese population.

Mechanical stress-initiated signal transduction in vascular smooth muscle cells in vitro and in vivo

Increasing evidence has been demonstrated that hypertension-initiated abnormal biomechanical stress is strongly associated with cardio-/cerebrovascular diseases e.g. atherosclerosis, stroke, and heart failure, which is main cause of morbidity and mortality. How the cells in the cardiovascular system sense and transduce the extracellular physical stimuli into intracellular biochemical signals is a crucial issue for understanding the mechanisms of the disease development. Recently, collecting data derived from our and other laboratories showed that many kinds of molecules in the cells such as receptors, ion channels, caveolin, G proteins, cell cytoskeleton, kinases and transcriptional factors could serve as mechanoceptors directly or indirectly in response to mechanical stimulation implying that the activation of mechanoceptors represents a non-specific manner. The sensed signals can be further sorted and/or modulated by processing of the molecules both on the cell surface and by the network of intracellular signaling pathways resulting in a sophisticated and dynamic set of cues that enable cardiovascular cell responses. The present review will summarise the data on mechanotransduction in vascular smooth muscle cells and formulate a new hypothesis, i.e. a non-specific activation of mechanoceptors followed by a variety of signal cascade activation. The hypothesis could provide us some clues for exploring new therapeutic targets for the disturbed mechanical stress-initiated diseases such as hypertension and atherosclerosis.

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

The gastric mucosal surface was observed using the magnifying fibergastroscope (FGS-ML), and the fine gastric mucosal patterns, which were even smaller than one unit of gastric area, were examined at a magnification of about 30. For simplicification, we classified these patterns by magnifying endoscopy in the following ways; FP, FIP, FSP, SP and MP, modifying Yoshii's classification under the dissecting microscope. The FIP, which was found to have round and long elliptical gastric pits, is a new addition to our endoscopic classification. The relationship between the FIP and the intermediate zone was evaluated by superficial and histological studies of surgical and biopsy specimens. The width of the band of FIP seems to be related to the severity of atrophic gastritis. Also, the transformation of FP to FIP was assessed by comparing specimens taken from the resected and residual parts of the stomach, respectively. Moreover, it appears that severe gastritis occurs in the gastric mucosa which shows a FIP. Therefore, we consider that the FIP indicates the position of the atrophic border.