Chronic ethanol consumption reduces adrenomedullin-induced relaxation in the isolated rat aorta

Association of gene polymorphisms in MYH11 and TGF-β signaling with the susceptibility and clinical outcomes of DeBakey type III aortic dissection

To investigate the association of myosin heavy chain protein 11 (MYH11) and transforming growth factor β signaling-related gene polymorphisms with the susceptibility of DeBakey type III aortic dissection (AD) and its clinical outcomes. Four single-nucleotide polymorphism (SNPs) (MYH11 rs115364997, rs117593370, TGFB1 rs1800469, and TGFBR1 rs1626340) were analyzed in patients with DeBakey III AD (173) and healthy participants (335). Gene-gene and gene-environment interactions were evaluated using generalized multifactor dimensionality reduction. The patients were followed up for a median of 55.7 months. MYH11 rs115364997 G or TGFBR1 rs1626340 A carriers had an increased risk of DeBakey type III AD. MYH11, TGFB1, TGFBR1, and environment interactions contributed to the risk of DeBakey type III AD (cross-validation consistency = 10/10, P = 0.001). Dominant models of MYH11 rs115364997 AG + GG genotype (HR = 2.443; 95%CI: 1.096-5.445, P = 0.029), TGFB1 rs1800469 AG + GG (HR = 2.303; 95%CI: 1.069-4.96, P = 0.033) were associated with an increased risk of mortality in DeBakey type III AD. The dominant model of TGFB1 rs1800469 AG + GG genotype was associated with an increased risk of recurrence of chest pain in DeBakey type III AD (HR = 1.566; 95%CI: 1.018-2.378, P = 0.041). In conclusions, G carriers of MYH11 rs115364997 or TGFB1 rs1800469 may be the poor prognostic indicators of mortality and recurrent chest pain in DeBakey type III AD. The interactions of gene-gene and gene-environment are associated with the risk of DeBakey type III AD.

Protective effect of apple polyphenols on chronic ethanol exposure-induced neural injury in rats

Apple polyphenols (AP) have attracted much attention due to their various bioactivities. In this study, the protective effect of AP against chronic ethanol exposure-induced neural injury as well as the possible mechanisms were investigated. Body weight, daily average food intake and daily average fluid intake were measured and daily average ethanol consumption was calculated. The influences of AP on motor behavior and memory were detected by locomotor activity test, rotarod test, beam walking test, and Y maze test and novel object recognition test, respectively. The changes of blood ethanol concentration and the oxidative stress were also measured. AP improved chronic ethanol exposure-induced the inhibition of body weight and the decrease of daily average food intake, but did not influence the daily average fluid intake and the daily average ethanol intake, indicating that the improve effect of AP did not result from the decrease of ethanol intake. Motor activity and motor coordination were not influenced after chronic ethanol exposure though the blood ethanol concentration was higher than that in control group. AP improved significantly chronic ethanol-induced the memory impairment and the hippocampal CA1 neurons damage. Further studies found that AP decreased the contents of NO and MDA and increased the levels of T-AOC and GSH in the hippocampus of rats. These results suggest that AP exerts a protective effect against chronic ethanol-induced memory impairment through improving the oxidative stress in the hippocampus.

Dysregulated mitogen-activated protein kinase and matrix metalloproteinase in ethanol-induced cavernosal dysfunction

We evaluated the effects of ethanol consumption on the mitogen-activated protein kinases (MAPK) and metalloproteinases (MMP) pathways in the rat cavernosal smooth muscle (CSM). Male Wistar rats were treated with ethanol (20% v/v) for 6 weeks. Quantitative real-time polymerase chain reaction experiments showed that ethanol consumption did not alter mRNA levels of p38MAPK, SAPK/JNK, ERK1/2, MMP-2, or MMP-9 in the rat CSM. Western immunoblotting experiments revealed decreased protein expression of p38MAPK and phosphorylation of SAPK/JNK in the CSM from ethanol-treated rats. Additionally, ethanol consumption decreased the expression of MMP-2. Functional assays showed that SP600125, an inhibitor of SAPK/JNK, prevented the increase in endothelin (ET)-1-induced contraction in the CSM from ethanol-treated rats. Treatment with ethanol decreased MMP-2 activity, but did not change net MMP activity in the rat CSM. Ethanol consumption increased the circulating levels of MMP-2, MMP-9, and TIMP-2 as well as the MMP-9/TIMP-1 ratio. The major finding of our study is that ethanol consumption down-regulates both MAPK and MMP pathways in the rat CSM, whereas it increases the circulating levels of MMP-9. Additionally, we found that SAPK/JNK plays a role in ethanol-induced increase on ET-1 contraction in the isolated rat CSM.

Pharmacological characterization of the relaxant effect induced by adrenomedullin in rat cavernosal smooth muscle

The aim of the present study was to determine the mechanisms underlying the relaxant effect of adrenomedullin (AM) in rat cavernosal smooth muscle (CSM) and the expression of AM system components in this tissue. Functional assays using standard muscle bath procedures were performed in CSM isolated from male Wistar rats. Protein and mRNA levels of pre-pro-AM, calcitonin receptor-like receptor (CRLR), and Subtypes 1, 2 and 3 of the receptor activity-modifying protein (RAMP) family were assessed by Western immunoblotting and quantitative real-time polymerase chain reaction, respectively. Nitrate and 6-keto-prostaglandin F_1α (6-keto-PGF_1α; a stable product of prostacyclin) levels were determined using commercially available kits. Protein and mRNA of AM, CRLR, and RAMP 1, -2, and -3 were detected in rat CSM. Immunohistochemical assays demonstrated that AM and CRLR were expressed in rat CSM. AM relaxed CSM strips in a concentration-dependent manner. AM_22-52, a selective antagonist for AM receptors, reduced the relaxation induced by AM. Conversely, CGRP_8-37, a selective antagonist for calcitonin gene-related peptide receptors, did not affect AM-induced relaxation. Preincubation of CSM strips with N^G-nitro-L-arginine-methyl-ester (L-NAME, nitric oxide synthase inhibitor), 1H-(1,2,4)oxadiazolo[4,3-a]quinoxalin-1-one (ODQ, quanylyl cyclase inhibitor), Rp-8-Br-PET-cGMPS (cGMP-dependent protein kinase inhibitor), SC560 [5-(4-chlorophenyl)-1-(4-methoxyphenyl)-3-trifluoromethyl pyrazole, selective cyclooxygenase-1 inhibitor], and 4-aminopyridine (voltage-dependent K⁺ channel blocker) reduced AM-induced relaxation. On the other hand, 7-nitroindazole (selective neuronal nitric oxide synthase inhibitor), wortmannin (phosphatidylinositol 3-kinase inhibitor), H89 (protein kinase A inhibitor), SQ22536 [9-(tetrahydro-2-furanyl)-9H-purin-6-amine, adenylate cyclase inhibitor], glibenclamide (selective blocker of ATP-sensitive K⁺ channels), and apamin (Ca²⁺-activated channel blocker) did not affect AM-induced relaxation. AM increased nitrate levels and 6-keto-PGF_1α in rat CSM. The major new contribution of this research is that it demonstrated expression of AM and its receptor in rat CSM. Moreover, we provided evidence that AM-induced relaxation in this tissue is mediated by AM receptors by a mechanism that involves the nitric oxide-cGMP pathway, a vasodilator prostanoid, and the opening of voltage-dependent K⁺ channels.

Pharmacological characterisation of the mechanisms underlying the relaxant effect of adrenomedullin in the rat carotid artery

OBJECTIVES

We investigated the mechanisms underlying the relaxant effect of adrenomedullin (AM) in the rat carotid artery and verified the expression of AM system components in this tissue.

METHODS

The carotid artery was isolated from male Wistar rats and immunohistochemical, Western immunoblotting, real-time polymerase chain reaction and functional assays were conducted.

KEY FINDINGS

Protein and mRNA expression of AM, calcitonin receptor-like receptor (CRLR) and receptor activity-modifying proteins (RAMP)1, 2, 3 were detected in carotid segments from male Wistar rats. Immunohistochemical assays showed that AM and CRLR receptors are expressed in the endothelium and smooth muscle cells. Functional assays showed that AM concentration dependently relaxed carotid rings with intact endothelium. Endothelial removal reduced, but not abolished, the relaxation induced by AM. AM22-52 (selective antagonist for AM receptors) and calcitonin gene-related peptide (CGRP)8-37 (selective CGRP receptor antagonist) reduced AM-induced relaxation in endothelium-intact rings. Pre-incubation of endothelium-intact rings with N-nitro-L-arginine methyl ester, 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one or Rp-8-Bromo-?-phenyl-1,N2-ethenoguanosine 3',5'cyclic monophosphorothioate reduced AM-induced relaxation. Inhibition of cyclooxygenase-1 and protein kinase A (PKA) reduced AM-induced relaxation. The relaxation induced by AM was attenuated by the K(+) channel blockers apamin and glibenclamide. AM increased nitrate levels and 6-keto-prostaglandin F1α (stable product of prostacyclin) in the rat carotid. In endothelium-denuded rings, AM22-52 , glibenclamide and PKA inhibition by H89 reduced AM-induced relaxation.

CONCLUSIONS

The novelty of this work is that it first demonstrated functionally that AM-induced relaxation is mediated by AM and CGRP receptors located on the endothelium and AM receptors located on smooth muscle of rat carotid arteries. AM-induced relaxation involves the nitric oxide-cGMP pathway, a vasodilator prostanoid, the opening of K(+) channels and the activation of PKA.

Long-term alcohol consumption is an independent risk factor of hypertension development in northern China: evidence from Kailuan study

OBJECTIVE

The purpose of the present study was to determine the impact of alcohol consumption on the incidence of hypertension.

METHODS

A total of 32,389 male coal mine workers from Kailuan Coal Group in northern China (Kailuan study), free of hypertension, myocardial infarction, stroke, transient ischemia attack and cancer, were followed up every 2 years for 4 years. The average alcohol intake during the past year was reported as baseline.

RESULTS

During 4 years of follow-up, 9151 out of 32,389 workers developed hypertension categorically. At the end of the follow-up, the cumulative incidence of hypertension in relation to daily alcoholic intake of none, 1-24, 25-49, 50-99, 100-149 and at least 150 g was 25.03, 28.82, 30.10, 37.07, 40.14 and 42.49%, respectively. After adjusting for age, we found that the relative risk of hypertension in those who were never exposed to alcohol was the lowest, with the group 25-49 g/day being the next. This trend was unchanged after adjustment for age, exercise, smoking status, job type and salt intake. After further adjustment for BMI, history of high cholesterol and diabetes mellitus, a positive, linear association between alcohol consumption and the risk of hypertension was found. Models stratified by baseline SBP (<120 and 120-139 mmHg) or DBP (<80 and 80-89 mmHg) did not alter the trend.

CONCLUSION

The Kailuan study demonstrates that long-term alcohol intake is an independent risk factor of incident hypertension in a large cohort of coal mine workers. Even light-to-moderate alcohol consumption increases the risk of incident hypertension.

Chronic alcohol consumption alters periodontal health in rats

BACKGROUND

The aim of this study was to assess the effects of chronic alcohol consumption on periodontitis development in rats.

METHODS

Periodontal disease was experimentally induced by lipopolysaccharide (LPS; 2 mg/ml) injections into the gingival tissue around first upper and lower molar's neck, and into the interdental space between first and second molars. This protocol was repeated for 6 weeks on days 1, 3, and 5 of each week. Chronic alcohol consumption was induced by 20% ethanol (EtOH) as the only liquid source during 4 months.

RESULTS

Chronic alcohol consumption by itself increased alveolar bone loss and biological mediators of periodontal disease such as prostaglandin E2 (PGE2 ) content on gingival tissue, and inducible nitric oxide synthase activity plus PGE2 content in submandibular gland. Unexpectedly, alcohol consumption did not increase the damage evoked by the proved model of LPS injections for periodontitis induction.

CONCLUSIONS

Results suggest 20% alcohol consumption during 4 months generates differential effects on oral health of rats, depending on its pathophysiological state: It would exacerbate the inflammatory condition when periodontal damage is absent, but it would not when damage is installed.

Hypertension and chronic ethanol consumption: What do we know after a century of study?

The influences of life habits on the cardiovascular system may have important implications for public health, as cardiovascular diseases are among the leading causes of shorter life expectancy worldwide. A link between excessive ethyl alcohol (ethanol) consumption and arterial hypertension was first suggested early last century. Since then, this proposition has received considerable attention. Support for the concept of ethanol as a cause of hypertension derives from several epidemiologic studies demonstrating that in the general population, increased blood pressure is significantly correlated with ethanol consumption. Although the link between ethanol consumption and hypertension is well established, the mechanism through which ethanol increases blood pressure remains elusive. Possible mechanisms underlying ethanol-induced hypertension were proposed based on clinical and experimental observations. These mechanisms include an increase in sympathetic nervous system activity, stimulation of the renin-angiotensin-aldosterone system, an increase of intracellular Ca²⁺ in vascular smooth muscle, increased oxidative stress and endothelial dysfunction. The present report reviews the relationship between ethanol intake and hypertension and highlights some mechanisms underlying this response. These issues are of interest for the public health, as ethanol consumption contributes to blood pressure elevation in the population.

Association of adrenomedullin gene polymorphisms and blood pressure in a Chinese population

Genetic factors may determine an individual's blood pressure (BP) level and risk for hypertension. This study aimed to examine the associations between genetic variants of the adrenomedullin (ADM) gene and essential hypertension, as well as BP levels, in a Chinese Han population. In this study, 2410 hypertensive patients and 2346 normal controls were recruited. Three tagging single-nucleotide polymorphisms (SNPs) based on the HapMap CHB data were selected and genotyped. No significant associations between the three SNPs of the ADM gene and hypertension status were observed. However, SNP rs4399321 was found to be associated with BP levels among the controls. GG homozygotes for this SNP had higher systolic BP (SBP) levels than carriers of the A allele (P=0.002). Particularly in non-drinkers, GG homozygotes had significantly higher SBP (116.9±0.9 vs. 113.7±0.3 mm Hg, P=0.001) and diastolic (74.0±0.7 vs. 72.6±0.2 mm Hg, P=0.046) BP levels than carriers of the A allele. Neither rs4910118 nor rs7944706 was associated with BP levels in the controls either before or after being stratified by drinking status. The results of this study showed that genetic variations in the ADM gene were not associated with the risk of hypertension in a Chinese population. However, the genotype at common variation rs4399321 may influence the BP level in normotensive subjects, especially among non-drinkers. In addition, replications in other populations and further functional studies are required to confirm and interpret the association of ADM with BP.