Eicosapentaenoic Acid Ameliorates Cardiac Fibrosis and Tissue Inflammation in Spontaneously Hypertensive Rats

Hypertension affects 1 in 3 adults in the United States and leads to left ventricular (LV) concentric hypertrophy, interstitial fibrosis, and increased stiffness. The treatment of cardiac fibrosis remains challenging and empiric. Eicosapentaenoic acid (EPA) is an omega-3 polyunsaturated fatty acid that is highly effective in reducing cardiovascular events in patients and cardiac fibrosis and hypertrophy in animals when administered before pressure overload by promoting the increase of anti-inflammatory M1 macrophages. In this study, we investigated whether EPA mitigates the exacerbation of cardiac remodeling and fibrosis induced by established hypertension, a situation that closely recapitulates a clinical scenario. Twelve-week-old spontaneously hypertensive rats were randomized to eat an EPA-enriched or control diet for 20 weeks. We report that rats eating the EPA-enriched diet exhibited a reduction of interstitial cardiac fibrosis and ameliorated LV diastolic dysfunction despite the continuous increase in blood pressure. However, we found that EPA did not have an impact on cardiac hypertrophy. Interestingly, the EPA diet increased mRNA expression of M2 macrophage marker Mrc1 and interleukin-10 in cardiac tissue. These findings indicated that the antifibrotic effects of EPA are mediated in part by phenotypic polarization of macrophages toward anti-inflammatory M2 macrophages and increases of the anti-inflammatory cytokine, interleukin-10. In summary, EPA prevents the exacerbation of cardiac fibrosis and LV diastolic dysfunction during sustained pressure overload. EPA could represent a novel treatment strategy for hypertensive cardiomyopathy.     

Heterogeneity in Arterial Remodeling among Sublines of Spontaneously Hypertensive Rats

Objectives

Spontaneously hypertensive rats (SHR) have been used frequently as a model for human essential hypertension. However, both the SHR and its normotensive control, the Wistar Kyoto rat (WKY), consist of genetically different sublines. We tested the hypothesis that the pathophysiology of vascular remodeling in hypertension differs among rat sublines.

Methods and Results

We studied mesenteric resistance arteries of WKY and SHR from three different sources, at 6 weeks and 5 months of age. Sublines of WKY and SHR showed differences in blood pressure, body weight, vascular remodeling, endothelial function, and vessel ultrastructure. Common features in small mesenteric arteries from SHR were an increase in wall thickness, wall-to-lumen ratio, and internal elastic lamina thickness.

Conclusions

Endothelial dysfunction, vascular stiffening, and inward remodeling of small mesenteric arteries are not common features of hypertension, but are subline-dependent. Differences in genetic background associate with different types of vascular remodeling in hypertensive rats.     

基质金属蛋白酶- 9, 组织抑制因子- 1 在进展期 胃癌中的表达与意义

目的：研究基质金属蛋白酶-9（matrix metalloproteinase-9,MMP-9）及其组织抑制因子-1（tissue inhibitor of metallopmteinase—1,TMP-1）在进展期胃癌中的表达情况,探讨二者的表达与胃癌侵袭转移闻的关系及二者间的联系。方法：应用免疫组化方法检测70例进展期胃癌标本中MMP-9,TIMP-1的表达,并进行回顾性随访。结果：馒反肌层以上者MMP-9的阳性表达（66．67％）明显高于肿瘤局限于粘膜、粘膜下者（20％P〈0.01）。MMP-9阳性表达与胃癌的淋巴转移与肝转移有相关性（P〈0．01）。TIMP-1的表达随胃癌浸润深度增加而减少,当肿瘤突破浆膜时TIMP-1的表达呈现陡降趋势（P〈0．01）。结论：MMP-9的过阳性表达和TIMP-1的表达失衡可能与胃癌转移行为有关。TIMP-1可能抑制胃癌的浸润转移。     

羌活地黄汤对大鼠佐剂性关节炎软骨金属蛋白酶-1、13及基质金属蛋白酶抑制剂-1的影响

目的：观察羌活地黄汤对大鼠佐剂性关节炎软骨中基质金属蛋白酶-1（marxmetalloproteinase-1,MMP-1）、基质金属蛋白酶-13（matrixmetalloproteinase．13,MMP-13）及基质金属蛋白酶抑制剂-1（tissueinhibitorofmetalloprotease-1,TIMP-1）表达的影响。方法：Wistar大鼠32只,随机分为正常对照组、模型组、雷公藤对照组、羌活地黄汤组。制作大鼠佐剂性关节炎模型,造模第14天开始给药。羌活地黄汤组予混有羌活地黄汤的颗粒饲料,雷公藤组给予混有雷公藤多甙的饲料,正常组及模型组均给予普通饲料。第28天分别取各组胫骨平台关节软骨,采用免疫组织化学染色测定软骨中MMP-1、13及T1MP—1表达的阳性指数。结果：模型组MMP-1、MMP-13及TIMP—1表达的阳性指数水平明显高于正常组,差异有统计学意义（P〈0．01）,羌活地黄汤组MMP-1、13及TIMP-1表达阳性指数低于模型组,差异有统计学意义（P〈0．05）。结论：羌活地黄汤可能是通过调控软骨细胞外基质中MMP．1、MMP—13及TIMP-1表达变化而维持软骨的动态平衡,从而延缓RA骨骼破坏。     

基质金属蛋白酶-9及金属蛋白酶组织抑制剂-1在孕鼠胎盘形成中期的表达模式

目的探讨基质金属蛋白酶-9(MMP-9)及金属蛋白酶组织抑制剂-1(TIMP-1)在孕鼠胎盘形成中期的表达模式。方法 HE染色观察孕鼠第9天至第14天(D9~D14)胎盘形态结构的变化,同时免疫组织化学法检测相应天数胎盘中MMP-9和TIMP-1的表达情况。结果 HE染色结果显示孕鼠D11时胎盘的3层结构开始形成,包括蜕膜区(Dec)、海绵滋养细胞层(Sp)和迷路区(Lab);随着妊娠天数的增加,Dec区域逐渐缩小,Sp和Lab区域增大;免疫组化表明,MMP-9和TIMP-1均表达于细胞浆和细胞核中,MMP-9强表达于D9和D10胎盘的外胎盘锥中,D10~D13的Dec、Sp和D11~D13的滋养巨细胞中。MMP-9在D11的Lab,D12的Dec和Lab,D13的Dec、Sp、Lab区域中的阳性细胞的积分光密度值与D14胎盘中对应值比较,差异有统计学意义(P0.05);TIMP-1在D9~D12的Dec区域中的阳性细胞的积分光密度值与D14胎盘中对应值比较,差异有统计学意义(P0.05);MMP-9/TIMP-1在D9、D11的Dec及D12的Lab区域中的比值与D14胎盘中对应值比较,差异有统计学意义(P0.05),在D10、D12的Dec和D13的Lab区域中的比值与D14胎盘中对应值比较,差异有高度统计学意义(P0.01)。结论 MMP-9和TIMP-1在孕鼠胎盘中的协同表达可能参与调节胎盘的形成。     

Modest Elevation in BNP in Asymptomatic Hypertensive Patients Reflects Sub-Clinical Cardiac Remodeling,Inflammation and Extracellular Matrix Changes

In asymptomatic subjects B-type natriuretic peptide (BNP) is associated with adverse cardiovascular outcomes even at levels well below contemporary thresholds used for the diagnosis of heart failure. The mechanisms behind these observations are unclear. We examined the hypothesis that in an asymptomatic hypertensive population BNP would be associated with sub-clinical evidence of cardiac remodeling, inflammation and extracellular matrix (ECM) alterations. We performed transthoracic echocardiography and sampled coronary sinus (CS) and peripheral serum from patients with low (n = 14) and high BNP (n = 27). Peripheral BNP was closely associated with CS levels (r = 0.92, p<0.001). CS BNP correlated significantly with CS levels of markers of collagen type I and III turnover including: PINP (r = 0.44, p = 0.008), CITP (r = 0.35, p = 0.03) and PIIINP (r = 0.35, p = 0.001), and with CS levels of inflammatory cytokines including: TNF-α (r = 0.49, p = 0.002), IL-6 (r = 0.35, p = 0.04), and IL-8 (r = 0.54, p<0.001). The high BNP group had greater CS expression of fibro-inflammatory biomarkers including: CITP (3.8±0.7 versus 5.1±1.9, p = 0.007), TNF-α (3.2±0.5 versus 3.7±1.1, p = 003), IL-6 (1.9±1.3 versus 3.4±2.7, p = 0.02) and hsCRP (1.2±1.1 versus 2.4±1.1, p = 0.04), and greater left ventricular mass index (97±20 versus 118±26 g/m², p = 0.03) and left atrial volume index (18±2 versus 21±4, p = 0.008). Our data provide insight into the mechanisms behind the observed negative prognostic impact of modest elevations in BNP and suggest that in an asymptomatic hypertensive cohort a peripheral BNP measurement may be a useful marker of an early, sub-clinical pathological process characterized by cardiac remodeling, inflammation and ECM alterations.     

Sinapic Acid Prevents Hypertension and Cardiovascular Remodeling in Pharmacological Model of Nitric Oxide Inhibited Rats

Objectives

Hypertensive heart disease is a constellation of abnormalities that includes cardiac fibrosis in response to elevated blood pressure, systolic and diastolic dysfunction. The present study was undertaken to examine the effect of sinapic acid on high blood pressure and cardiovascular remodeling.

Methods

An experimental hypertensive animal model was induced by L-NAME intake on rats. Sinapic acid (SA) was orally administered at a dose of 10, 20 and 40 mg/kg body weight (b.w.). Blood pressure was measured by tail cuff plethysmography system. Cardiac and vascular function was evaluated by Langendorff isolated heart system and organ bath studies, respectively. Fibrotic remodeling of heart and aorta was assessed by histopathologic analyses. Oxidative stress was measured by biochemical assays. mRNA and protein expressions were assessed by RT-qPCR and western blot, respectively. In order to confirm the protective role of SA on endothelial cells through its antioxidant property, we have utilized the in vitro model of H₂O₂-induced oxidative stress in EA.hy926 endothelial cells.

Results

Rats with hypertension showed elevated blood pressure, declined myocardial performance associated with myocardial hypertrophy and fibrosis, diminished vascular response, nitric oxide (NO) metabolites level, elevated markers of oxidative stress (TBARS, LOOH), ACE activity, depleted antioxidant system (SOD, CAT, GPx, reduced GSH), aberrant expression of TGF-β, β-MHC, eNOS mRNAs and eNOS protein. Remarkably, SA attenuated high blood pressure, myocardial, vascular dysfunction, cardiac fibrosis, oxidative stress and ACE activity. Level of NO metabolites, antioxidant system, and altered gene expression were also repaired by SA treatment. Results of in vitro study showed that, SA protects endothelial cells from oxidative stress and enhance the production of NO in a concentration dependent manner.

Conclusions

Taken together, these results suggest that SA may have beneficial role in the treatment of hypertensive heart disease by attenuating fibrosis and oxidative stress through its antioxidant potential.     

自发性高血压大鼠血管平滑肌及心肌内成纤维细胞生长特性的研究

目的　探讨自发性高血压大鼠(spontaneously hypertensive rats, SHR)主动脉平滑肌细胞(aorta smooth muscle cell, ASMC)与心肌内成纤维细胞(cardiac fibroblast, CFB)在体外培养生长的特性。方法　16周龄自发性高血压大鼠(SHR)和正常大鼠(WKY)测血压后处死,取心脏与胸主动脉,组织块法分别培养CFB与ASMC)。分别观察(1)CFB     

Therapeutic Sesamol Attenuates Monocrotaline-Induced Sinusoidal Obstruction Syndrome in Rats by Inhibiting Matrix Metalloproteinase-9

We investigated the therapeutic effect of sesamol against monocrotaline-induced sinusoidal obstruction syndrome (SOS) in rats. Male Sprague–Dawley rats were gavaged with a single dose of monocrotaline (90 mg/kg) to induce SOS. Sesamol (5, 10, 20, and 40 mg/kg) was subcutaneously injected 24 h after monocrotaline treatment. Control rats were given saline only. Aspartate transaminase, alanine transaminase, mast cells, CD 68⁺ Kupffer cells, neutrophils, myeloperoxidase, matrix metalloproteinase-9 (MMP-9), tissue inhibitor of matrix metalloproteinase-1 (TIMP-1), laminin, and collagen were assessed 48 h after monocrotaline treatment. All tested parameters, except for TIMP-1, laminin, and collagen, were significantly higher in monocrotaline-treated rats than in control rats, and, except for TIMP-1, laminin, and collagen, significantly lower in sesamol-treated rats than in monocrotaline-treated rats. In addition, liver pathology revealed that sesamol offered significant protection against SOS. We conclude that a single dose of sesamol therapeutically attenuated SOS by decreasing the recruitment of inflammatory cells, downregulating MMP-9, and upregulating TIMP-1 expression.     

COPD大鼠模型气道MMP-9和TIMP-1表达的研究

目的:探讨基质金属蛋白酶-9(MMP-9)及组织金属蛋白酶抑制因子-1(TIMP-1)在慢性阻塞性肺疾病(COPD)大鼠模型气道的表达.方法:Wistar大鼠25只随机分为COPD模型组和正常对照组,采用单纯被动吸烟法建立COPD大鼠模型,以酶联免疫吸附法(ELISA)测定两组大鼠血清及支气管肺泡灌洗液(BALF)中MMP-9和TIMP-1的表达水平.结果:COPD组血清及BALF中MMP-9和TIMP-1的表达明显高于正常组(P＜0.05和P＜0.01);COPD组血清及BALF的MMP-9/TIMP-1低于正常组血清及BALF的MMP-9/TIMP-1,差异有统计学意义(P＜0.05);COPD组和正常组BALF中MMP-9和TIMP-1水平高于血清中MMP-9和TIMP-1水平,但差异无统计学意叉(P＞0.05).结论:MMP-9和TIMP-1平衡失调参与了COPD的发病,调节MMP-9和TIMP-1的平衡可能是治疗COPD的新方法.     

Sex Hormones Promote Opposite Effects on ACE and ACE2 Activity,Hypertrophy and Cardiac Contractility in Spontaneously Hypertensive Rats

BackgroundThere is growing interest in sex differences and RAS components. However, whether gender influences cardiac angiotensin I-converting enzyme (ACE) and angiotensin-converting enzyme 2 (ACE2) activity is still unknown. In the present work, we determined the relationship between ACE and ACE2 activity, left ventricular function and gender in spontaneously hypertensive rats (SHRs).ConclusionOvariectomy leads to increased cardiac hypertrophy, ACE2 activity, PLB expression and PLB to SERCA2a ratio, and worsening of hemodynamic variables, whereas in males the removal of testosterone has the opposite effects on RAS components.     

Bortezomib,a Proteasome Inhibitor,Attenuates Angiotensin II-Induced Hypertension and Aortic Remodeling in Rats

Background

Hypertension is a highly prevalent disorder and a major risk factor for cardiovascular diseases. Hypertensive vascular remodeling is the pathological mal-adaption of blood vessels to the hypertensive condition that contributes to further development of high blood pressure and end-organ damage. Hypertensive remodeling involves, at least in part, changes in protein turnover. The ubiquitin proteasome system (UPS) is a major protein quality and quantity control system. This study tested the hypothesis that the proteasome inhibitor, bortezomib, would attenuate AngII-induced hypertension and its sequelae such as aortic remodeling in rats.

Methodology/Principal Findings

Male Sprague Dawley rats were subjected to AngII infusion for two weeks in the absence or presence of bortezomib. Mean arterial pressure was measured in conscious rats. Aortic tissue was collected for estimation of wall area, collagen deposition and expression of tissue inhibitors of matrix metalloproteases (TIMP), Ki67 (a marker of proliferation), reactive oxygen species (ROS) and VCAM-1 (a marker of inflammation). AngII infusion increased arterial pressure significantly (160±4 mmHg vs. vehicle treatment 133±2 mmHg). This hypertensive response was attenuated by bortezomib (138±5 mmHg). AngII hypertension was associated with significant increases in aortic wall to lumen ratio (∼29%), collagen deposition (∼14%) and expression of TIMP1 and TIMP2. AngII also increased MMP2 activity, proteasomal chymotrypsin-like activity, Ki67 staining, ROS generation and VCAM-1 immunoreactivity. Co-treatment of AngII-infused rats with bortezomib attenuated these AngII-induced responses.

Conclusions

Collectively, these data support the idea that proteasome activity contributes to AngII-induced hypertension and hypertensive aortic vascular remodeling at least in part by modulating TIMP1/2 and MMP2 function. Preliminary observations are consistent with a role for ROS, inflammatory and proliferative mechanisms in this effect. Further understanding of the mechanisms by which the proteasome is involved in hypertension and vascular structural remodeling may reveal novel targets for pharmacological treatment of hypertension, hypertensive remodeling or both.     

Interferon-Gamma Increases the Ratio of Matrix Metalloproteinase-9/Tissue Inhibitor of Metalloproteinase-1 in Peripheral Monocytes from Patients with Coronary Artery Disease

Acute coronary syndromes (ACS) may be triggered by acute infections. Systemic production of interferon gamma (IFN-γ) is induced during infection and regulates the production of matrix metalloproteinases (MMPs) and their inhibitors (TIMPs), both important in plaque stability. This study evaluates the effect of IFN-γ on the MMPs/TIMP-1 ratio in cultured monocytes from 30 patients with stable coronary artery disease (CAD), 30 with unstable angina (UA) or non-ST-segment elevation myocardial infarction (NSTEMI), and 30 healthy blood donors. Supernatant concentrations of MMP-1, -2, -9, and TIMP-1 were measured by enzyme-linked immunoassays. Basal concentration of MMP-1 and TIMP-1 was similar between groups, while MMP-2 was higher in healthy individuals and MMP-9 in patients with UA/NSTEMI. Upon IFN-γ stimulation, MMP-9 secretion increased in all groups, while TIMP-1 decreased only in patients with CAD, which in turn result in a strikingly elevation in their mean MMP-9/TIMP-1 ratio. MMP-1/TIMP-1 and MMP-2/TIMP-1 ratios were <1.0 in basal conditions and after stimulation in all groups. Our results suggest that nonstimulated monocytes from patients with stable CAD show a similar behavior than those from healthy individuals. However, stimulation with IFN-γ induces an increase on the MMP-9/TIMP-1 ratio as high as that found in patients with ACS. Thus, it may bring biological plausibility to the association between acute infections and the development of ACS.     

Sex Differences in the Beneficial Cardiac Effects of Chronic Treatment with Atrial Natriuretic Peptide In Spontaneously Hypertensive Rats

Introduction

The aim of this study was to investigate both the effects of chronic treatment with atrial natriuretic peptide (ANP) on systolic blood pressure (SBP), cardiac nitric oxide (NO) system, oxidative stress, hypertrophy, fibrosis and apoptosis in spontaneously hypertensive rats (SHR), and sex-related differences in the response to the treatment.

Methods

10 week-old male and female SHR were infused with ANP (100 ng/hr/rat) or saline (NaCl 0.9%) for 14 days (subcutaneous osmotic pumps). SBP was recorded and nitrites and nitrates excretion (NOx) were determined. After treatment, NO synthase (NOS) activity, eNOS expression, thiobarbituric acid-reactive substances (TBARS) and glutathione concentration were determined in left ventricle, as well as the activity of glutathione peroxidase (GPx), catalase (CAT) and superoxide dismutase (SOD). Morphological studies in left ventricle were performed in slices stained with hematoxylin-eosin or Sirius red to identify collagen as a fibrosis indicator; immunohistochemistry was employed for identification of transforming growth factor beta; and apoptosis was evaluated by Tunel assay.

Results

Female SHR showed lower SBP, higher NO-system activity and less oxidative stress, fibrosis and hypertrophy in left ventricle, as well as higher cardiac NOS activity, eNOS protein content and NOx excretion than male SHR. Although ANP treatment lowered blood pressure and increased NOS activity and eNOS expression in both sexes, cardiac NOS response to ANP was more marked in females. In left ventricle, ANP reduced TBARS and increased glutathione concentration and activity of CAT and SOD enzymes in both sexes, as well as GPx activity in males. ANP decreased fibrosis and apoptosis in hearts from male and female SHR but females showed less end-organ damage in heart. Chronic ANP treatment would ameliorate hypertension and end-organ damage in heart by reducing oxidative stress, increasing NO-system activity, and diminishing fibrosis and hypertrophy.     

血管平滑肌细胞在自发性高血压大鼠颈动脉重构中的作用及替米沙坦的干预研究

观察血管平滑肌细胞(VSMCs)在自发性高血压大鼠(SHR)颈动脉重构中的作用及替米沙坦的干预效果.将30只12周龄的SHR随机分为高血压组(SHR)、替米沙坦高剂量组(TelH)、替米沙坦低剂量组(TelL),另设同性别、周龄的WKY大鼠为对照组(n=10),干预18周.观察各组大鼠收缩压(SBP)、颈动脉中膜厚度(MT)、中膜横截面积(MCSA)、中膜细胞平均核面积、颈动脉 VSMCs增殖指数(PI)及凋亡指数(AI)等的变化.结果显示: ①两周后TelH组SBP明显低于SHR组(P＜0.01),其降压作用持续至实验结束,而TelL组SBP与SHR组无显著性差异(P＞0.05);②SHR组的MT、MCSA分别明显高于WKY组(P＜0.01),TelH组的MT、MCSA分别明显低于SHR组(P＜0.01),TelL组的MT明显低于SHR组(P＜0.05);③SHR组中膜VSMCs平均核面积明显大于WKY组(P＜0.01),而TelH、TelL组分别小于SHR组(P＜0.05);④各组颈动脉中膜VSMCs的PI均无明显差异(P＞0.05);SHR组颈动脉中膜VSMCs的AI明显低于WKY组(P＜0.01),而TelH、TelL组明显高于SHR组(P＜0.01);SHR组颈动脉中膜VSMCs的PI/AI明显高于WKY组(P＜0.01),而TelH、TelL组明显低于SHR组(P＜0.01);⑤颈动脉中膜VSMCs的AI与中膜MCSA呈显著负相关(r = -0.871,P＜0.01 ).说明VSMCs的肥大和增殖/凋亡失衡可能在SHR颈动脉重构中起重要作用,替米沙坦除降压作用外,能通过减轻VSMCs肥大,增加VSMCs凋亡,使增殖/凋亡趋于平衡而减轻其重构.     

A Novel Role of Matrix Metalloproteinase-8 in Macrophage Differentiation and Polarization

Matrix metalloproteinase-8 (MMP8) has been shown to influence various cellular functions. As monocytes and macrophages (Mφ) express MMP8, we investigated if MMP8 played a role in macrophage differentiation and polarization. MMP8 expression was significantly increased during monocyte differentiation into Mφ. Monocyte-derived Mφ from MMP8-deficient mice expressed higher levels of M1-Mφ markers but lower levels of M2-Mφ markers than monocyte-derived Mφ from wild-type mice. Although Mφ from either MMP8-deficient or wild-type mice were inducible by interferon-γ into M1-Mφ, only wild-type Mφ but not MMP8-deficient Mφ could be induced into M2-Mφ by interleukin-4. However, MMP8-deficient Mφ exposed to conditioned culture media of wild-type Mφ developed a M2-Mφ phenotype. Compared with conditioned culture media of wild-type Mφ, conditioned culture media of MMP8-deficient Mφ contained a lower concentration of active transforming growth factor-β (TGF-β), an M2-Mφ inducer. Moreover, evidence also showed that the degradation of the TGF-β sequester, fibromodulin, was modulated by MMP8. The data indicate a previously unknown role of MMP8 in M2-Mφ polarization by cleaving fibromodulin and therefore increasing the bioavailability of the M2-Mφ inducer TGF-β.     

Matrix Metalloproteinases -8 and -9 and Tissue Inhibitor of Metalloproteinase-1 in Burn Patients. A Prospective Observational Study

IntroductionMatrix metalloproteinases (MMPs) -8 and -9 are released from neutrophils in acute inflammation and may contribute to permeability changes in burn injury. In retrospective studies on sepsis, levels of MMP-8, MMP-9, and tissue inhibitor of metalloproteinase-1 (TIMP-1) differed from those of healthy controls, and TIMP-1 showed an association with outcome. Our objective was to investigate the relationship between these proteins and disease severity and outcome in burn patients.MethodsIn this prospective, observational, two-center study, we collected plasma samples from admission to day 21 post-burn, and burn blister fluid samples on admission. We compared MMP-8, -9, and TIMP-1 levels between TBSA<20% (N = 19) and TBSA>20% (N = 30) injured patients and healthy controls, and between 90-day survivors and non-survivors. MMP-8, -9, and TIMP-1 levels at 24-48 hours from injury, their maximal levels, and their time-adjusted means were compared between groups. Correlations with clinical parameters and the extent of burn were analyzed. MMP-8, -9, and TIMP-1 levels in burn blister fluids were also studied.ResultsPlasma MMP-8 and -9 were higher in patients than in healthy controls (P<0.001 and P = 0.016), but only MMP-8 differed between the TBSA<20% and TBSA>20% groups. MMP-8 and -9 were not associated with clinical severity or outcome measures. TIMP-1 differed significantly between patients and controls (P<0.001) and between TBSA<20% and TBSA>20% groups (P<0.002). TIMP-1 was associated with 90-day mortality and correlated with the extent of injury and clinical measures of disease severity. TIMP-1 may serve as a new biomarker in outcome prognostication of burn patients.     

The Novel Mas agonist,CGEN-856S,Attenuates Isoproterenol-Induced Cardiac Remodeling and Myocardial Infarction Injury in Rats

CGEN-856S is a novel Mas agonist. Herein, we examined the effects of this peptide on isoproterenol (ISO)-induced cardiac remodeling and myocardial infarction (MI) injury. We also sought to determine whether CGEN-856S activates the underlying mechanisms related to Mas receptor activation. Heart hypertrophy and fibrosis were induced by ISO (2 mg·kg⁻¹·day⁻¹) in Wistar rats. After a 7-day treatment period with CGEN-856S (90 µg·kg⁻¹·day⁻¹) or vehicle, the cardiomyocyte diameter was evaluated in left ventricular sections stained with hematoxylin and eosin, and immunofluorescence labeling and quantitative confocal microscopy were used to quantify the deposition of type I and III collagen and fibronectin in the left ventricles. MI was induced by coronary artery ligation, and CGEN-856S (90 µg·kg⁻¹·day⁻¹) or saline was administered for 14 days. The Langendorff technique was used to evaluate cardiac function, and left ventricular sections were stained with Masson’s trichrome dye to quantify the infarct area. Using Chinese hamster ovary cells stably transfected with Mas cDNA, we evaluated whether CGEN-856S alters AKT and endothelial nitric oxide synthase (eNOS) phosphorylation. CGEN-856S reduced the degree of ISO-induced hypertrophy (13.91±0.17 µm vs. 12.41±0.16 µm in the ISO+CGEN-856S group). In addition, the Mas agonist attenuated the ISO-induced increase in collagen I, collagen III, and fibronectin deposition. CGEN-856S markedly attenuated the MI-induced decrease in systolic tension, as well as in +dT/dt and -dT/dt. Furthermore, CGEN-856S administration significantly decreased the infarct area (23.68±2.78% vs. 13.95±4.37% in the MI+CGEN-856S group). These effects likely involved the participation of AKT and NO, as CGEN-856S administration increased the levels of p-AKT and p-eNOS. Thus, our results indicate that CGEN-856S exerts cardioprotective effects on ISO-induced cardiac remodeling and MI-mediated heart failure in rats through a mechanism likely involving the eNOS/AKT pathway.     

Autophagic Signaling and Proteolytic Enzyme Activity in Cardiac and Skeletal Muscle of Spontaneously Hypertensive Rats following Chronic Aerobic Exercise

Hypertension is a cardiovascular disease associated with deleterious effects in skeletal and cardiac muscle. Autophagy is a degradative process essential to muscle health. Acute exercise can alter autophagic signaling. Therefore, we aimed to characterize the effects of chronic endurance exercise on autophagy in skeletal and cardiac muscle of normotensive and hypertensive rats. Male Wistar Kyoto (WKY) and spontaneously hypertensive rats (SHR) were assigned to a sedentary condition or 6 weeks of treadmill running. White gastrocnemius (WG) of hypertensive rats had higher (p<0.05) caspase-3 and proteasome activity, as well as elevated calpain activity. In addition, skeletal muscle of hypertensive animals had elevated (p<0.05) ATG7 and LC3I protein, LAMP2 mRNA, and cathepsin activity, indicative of enhanced autophagic signaling. Interestingly, chronic exercise training increased (p<0.05) Beclin-1, LC3, and p62 mRNA as well as proteasome activity, but reduced (p<0.05) Beclin-1 and ATG7 protein, as well as decreased (p<0.05) caspase-3, calpain, and cathepsin activity. Left ventricle (LV) of hypertensive rats had reduced (p<0.05) AMPKα and LC3II protein, as well as elevated (p<0.05) p-AKT, p-p70S6K, LC3I and p62 protein, which collectively suggest reduced autophagic signaling. Exercise training had little effect on autophagy-related signaling factors in LV; however, exercise training increased (p<0.05) proteasome activity but reduced (p<0.05) caspase-3 and calpain activity. Our results suggest that autophagic signaling is altered in skeletal and cardiac muscle of hypertensive animals. Regular aerobic exercise can effectively alter the proteolytic environment in both cardiac and skeletal muscle, as well as influence several autophagy-related factors in skeletal muscle of normotensive and hypertensive rats.