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Objective To examine the effects of exogenously administered intermedin (IMD,adrenomedullin-2) on arterial blood pressure,cardiac function and the cardiovascular IMD receptor system in spontaneously hypertensive rats (SHRs) as well as to investigate the associated mechanisms.Methods Thirteen week-old male rats were divided in Wistar Kyoto (WKY) group (n =12),SHR group (n =12),IMD group (SHRs infused with IMD 1-47 500 ng/kg per hour,n =12),and ADM group (SHRs infused with adrenomedullin 500 ng/kg per hour,n =12).Results A two-week continuous administration of low dose IMD 1-47 via mini-osmotic pumps markedly reduced blood pressure,the maximal rates of increase and decrease of left-ventricle pressure development (LV ± dp/dtmax),left ventricular systolic pressure and heart rate in SHRs.Furthermore,IMD also inhibited protein over-expression of cardiovascular IMD receptors,myocardial Receptor Activity-Modifying Proteins (RAMP1 and RAMP2),aortic RAMP1,RAMP2,RAMP3,and calcitonin receptor-like receptor (CRLR);suppressed up-regulation of aortic RAMP1,RAMP2,RAMP3 and CRLR gene expression; and markedly elevated the mRNA abundance of myocardial atrial natriuretic peptide (ANP) and myocardial brain natriuretic peptide (BNP).Additionally,IMD 1-47 administration in SHRs increased aortic cAMP concentration and reduced myocardial cAMP concentration.Conclusion These findings support the speculation that IMD,as a cardiovascular active peptide,is involved in blood pressure reduction and cardiac function amelioration during hypertension.The mechanism underlying this effect may involve IMD binding of a receptor complex formed by RAMPs and CRLR,and consequential regulation of cAMP levels and other cardiovascular active factors,such as ANP and BNP.
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Objective To test the hypothesis that IL-10 may promoting left ventricular remodeling and cardiac function by modulating extracellular matrix after acute myocardial infarction. Methods Male adult rats were randomly divided into three groups: control group (n=6) , MI/AAV2 group (n=16) and MI/AAV2-IL-10 group (n=16). Establishing animal modol of experimental myocardial infarction and recombinant adeno-associated virus type 2 (AAV)/IL-10 (AAV2-rhIL-10) and AAV2 were injected around the ischemic zone. Echocardiography parameters, hemodynamic parameters, left ventricular mass index (LVMI) , collagen volume fraction (CVF) , perivascu-lar circumferential area (PVCA) , collagen type Ⅰ & Ⅲ volume fraction and mRNA levels of collagen type Ⅰ & Ⅲ , matrix metalloproteinases-2 ( MMP-2 ) and tissue inhibitor of metalloproteinase-1 ( TIMP-1) were compared among the three groups. Results Improved cardiac function was observed in MI/AAV2-IL-10 group shown by echocardiography and hemodynamic examination. Four weeks after myocardial infarction, thickness of different parts of LV was not different in MI/AAV2-IL-10 group and MI/AAV2 group. Nevertheless CVF, PVCA and collagen type Ⅰ volume fraction was significantly descending in remote zone of MI/AAV2-IL-10 group compared with that of MI/ AAV2 group. The mRNA expression of collagen type I and MMP-2 was lower in MI/AAV2-IL-10 group than that in MI/AAV2 group. Conclusion Recombinant IL-10 expression mediated by AAV2-rhIL-10 transfection of rats' myocardium promotes LV remodeling and cardiac function after acute myocardial infarction. The promotion was partially achieved by inhibition myocardium collagen deposition.
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Objective To investigate the role of endogenous Hydrogen Sulfide (H2S) in airway inflammation and responsiveness in a rat model of chronic passive-smoking.Methods Male SD rats were randomly divided into a control group (breathing fresh air) and a passive smoking group [cigarette smoking (CS) passively] ,with 18 rats in each group.Six rats in each group were randomly intraporitoneally injected with normal saline, sodium hydrosulfide (NailS) or propargylglycine (PPG, an irreversible inhibitor of cystathionine-γ-lyase).The animals were divided into six subgroups,ie.Con group, Naris group, and PPG group, CS group, CS + Naris group, and CS + PPG group.After 4 months,lung histological change and airway tension were measured.The H2 S levels of plasma and lung tissue were analyzed by the sensitive sulphur electrode assay.The expression of cystathionine-γ-lyase (CSE) was measured by western blot.Results Compared with the Con group, CSE protein expression in lung tissues was increased in CS group(P < 0.05) ; the H2S levels of plasma were significantly higher in GS group,NariS group and CS + Naris group,and much lower in PPG group (P < 0.05, respectively).Compared with CS group, the H2 S levels of plasma were significantly higher in CS + Naris group, and much lower in CS + PPG group (P < 0.05, respectively).The H2S level of lung tissue in each group had no significant difference (P > 0.05).Compared with Con group, score of lung pathology was significant elevated, and the responsiveness of airway smooth muscles to Ach and KCI was significant augmented in CS group.Compared with CS group, the score of lung pathology was decreased, and the responsiveness of airway smooth muscles was decreased in CS + NariS group(P < 0.05), and vise versa in CS + PPG group (P < 0.01).Conclusion H2 S can alleviate airway inflammation and hyperresponsiveness induced by CS, and administration of H2S might be of clinical benefit in airway inflammation and airway responsiveness.
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The endoplasmic reticulum (ER) serves several important functions, mainly post-translational modification, folding and assembly of newly synthesized secretary proteins, synthesizing lipids and cellular calcium storage. Various factors can disrupt ER homeostasis and disturb its functions, which leads to the accumulation of unfolded and misfolded proteins and to potential cellular dysfunction and pathological consequences, collectively termed ER stress. Recent progress suggests that ER stress plays a key role in the immune response, diabetes, tumor growth, and some neurodegenerative diseases. In particular, ER stress is involved in several processes of cardiovascular diseases, such as ischemia/reperfusion injury, cardiomyopathy, cardiac hypertrophy, heart failure, and atherosclerosis. Further research on the relation of ER stress to cardiovascular diseases will greatly enhance the understanding of these pathological processes and provide novel avenues to potential therapies.
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Objective To test the hypothesis that IL-10 may promoting left ventricular remodeling and cardiac function by modulating extracellular matrix after acute myocardial infarction. Methods Male adult rats were randomly divided into three groups:control group (n=6),MI/AAV2 group (n=16) and MI/AAV2-IL-10 group (n=16). Establishing animal modol of experimental myocardial infarction and recombinant adeno-associated virus type 2 (AAV)/IL-10 (AAV2-rhIL-10) and AAV2 were injected around the ischemic zone. Echocardiography parameters,hemodynamic parameters,left ventricular mass index (LVMI),collagen volume fraction (CVF),perivascular circumferential area (PVCA),collagen type Ⅰ&Ⅲ volume fraction and mRNA levels of collagen type Ⅰ&Ⅲ,matrix metalloproteinases-2 (MMP-2) and tissue inhibitor of metalloproteinase-1 (TIMP-1) were compared among the three groups. Results Improved cardiac function was observed in MI/AAV2-IL-10 group shown by echocardiography and hemodynamic examination. Four weeks after myocardial infarction,thickness of different parts of LV was not different in MI/AAV2-IL-10 group and MI/AAV2 group. Nevertheless CVF,PVCA and collagen type Ⅰ volume fraction was significantly descending in remote zone of MI/AAV2-IL-10 group compared with that of MI/AAV2 group. The mRNA expression of collagen type I and MMP-2 was lower in MI/AAV2-IL-10 group than that in MI/AAV2 group. Conclusion Recombinant IL-10 expression mediated by AAV2-rhIL-10 transfection of rats' myocardium promotes LV remodeling and cardiac function after acute myocardial infarction. The promotion was partially achieved by inhibition myocardium collagen deposition.
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Objective To examine whether the two vascular paracrine/autocrine factors, angiotensin Ⅱ (Ang Ⅱ) and endothelin, participate in the pathogenesis of arterial calcification. Methods Nicotine and vitamin D3 treated rats were studied. Vascular calcification was confirmed by using Von Kossa staining, measurement of calcium content,45Ca2+ uptake assay and alkaline phosphatase (ALP) activity. The plasma and vascular Ang Ⅱ and endothelin levels were measured by using radioimmunoassay. Angiotensinogen and endothelin mRNA levels were determined by RTPCR. Results The arterial calcium content, 45Ca2+ uptake and ALP activity were increased in calcification groups compared with control ( P ＜ 0.01 ). Administration of the angiotensin receptor antagonist losartan, the endothelin receptor antagonist bosentan, and the angiotensin-converting enzyme inhibitor captopril reduced significantly the arterial calcium content, 45Ca2+ uptake and ALP activity. In addition, the plasma and aortic Ang Ⅱ and endothelin contents, and vascular angiotensinogen and endothelin mRNA expression were significantly up-regulated ( P ＜0.05).Conclusions These findings suggest that functional renin-angiotensin system and endothelin pathway are involved in vascular calcification, and that activation of these systems could potentiate pathogenesis of arterial calcification. ( J Geriatr Cardiol 2004;1(2) :108-113. )
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Objective:To investigate the changes of pulmonary IMD and its receptor system - calcitonin receptor-like receptor (CL) and receptor activity modifying proteins (RAMPs) mRNA in acute lung injury(ALI) induced by oleic acid of rats. Methods: Contents of IMD in plasma and lung homogenates were measured by radioimmunoassay(RIA). The lung mRNA of IMD, CL and RAMPs was determined by semi-quantitative RT-PCR. Results: Compared with control group, in ALI group, the contents of IMD_ 1-53 in plasma and lung homogenates were decreased by 20.8% and 74.5% (all P
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0.05) in vitamin D_3 plus nicotine (VDN) group. The values of +LV dp/dt_ max and-LV dp/dt_ max were significantly lower in VDN group (P
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Aim To observe the influence of hydrogen sulfide on L-arginine/nitric oxide synthase(NOS)/NO pathway,explore the interaction between H_2S and NO as cardiovascular regulatory gasotransmitters.Methods Aortic thin slices in vitro were administrated with NaHS(10~(-7) mol?L~(-1)～10~(-4) mol?L~(-1)),a donor of H_2S,and incubated for 4 hours,or 50 ?mol?L~(-1) NaHS and incubated for 2 h,4 h and 6 h,respectively.The nitrite production Was measured with greiss assay;NOS activity and L-arginine transportation,with isotope tracer method;the eNOS and CAT1-A gene expression,with RT-PCR.Results After being given with NaHS(50 ?mol?L~(-1)) one time,and incubating for 2 h,the nitrite production decreased by 62%,NOS activity reduced by 48% and L-arginine transport decreased by 50%.After incubation for 6 h,the nitrite production further was inhibited by 19%(P0.05).NaHS(10~(-7) mol?L~(-1)～10~(-4) mol?L~(-1)) inhibited the L-arginine/NOS/NO pathway in a dose-dependent manner,and IC_(50) was 0.499,3.198 and 3.927 ?mol?L~(-1)(P
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AIM To investigate effect of urotensin Ⅱ (UⅡ)on proliferation of aort a smooth muscle cells （ASMC）of rat and study the signal transduction pathway o f it. METHODS In cultured ASMC of rat, UⅡ was used to stimulate proliferation of these cells and levels of ［3H］-TdR incorporation were used to evaluate the speed of DNA synthesis, and different inhibitors were used to s tudy the action of different signal transduction pathway of mitogenic effect of UⅡ on VSMC. RESULTS 1×10-9～1×10-7 mol*L- 1 UⅡ caused marked concentration-dependent increasing of ［3H］-TdR i ncor poration of ASMC. ［3H］-TdR incorporation of 1×10-9,1×10-8 and 1×10-7 mol*L-1 UⅡ were 22%（P<0.05）, 57%（P<0.01）and 65%（P<0.01）higher than control. Nicardipine, H7, W7 and PD98059 , which are inhibitors of calcium channel, PKC, CaM-PK and MAPK respectively, inhibited the effects of UⅡ obviously, with the inhibitory rate by 55%（P< 0.01）, 27%（P<0.01）,18%（P<0.05）and 16%（P<0.05）respectively . CONCLUSION UⅡ is a strong mitogen for VSMC and the mitogenic e ffect of UⅡ is probably mediated by Ca2+, PKC, CaM-PK and MAPK signal tr ansduction pathway.
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Objective: To study the effect of urotensin(U Ⅱ) on nitric oxide synthase(NOS)/nitric oxide(NO) system in rat aorta. Methods: The aortic slices were incubated in vitro. The medium nitrite content, vascular NOS activities and cGMP content were measured. Results: After incubation of aorta for 1.5－3.0 h, UⅡ(10－9－10－7 mol*L－1) increased nitrite production ( 14.8%－80.9%, P<0.01) in dose-dependent manner. U Ⅱ significantly stimulated the total NOS activities, mainly activated constitutive NOS (P<0.05 or P<0.01), however, the inducible NOS activities were not altered (P>0.05). Incubation of aortic slices with U Ⅱ (10－9－10－7 mol*L－1) increased vascular cGMP content in dose-dependent manner. Co-incubation vascular tissue with U Ⅱ and GN-L-nitro-arginine, an inhibitor of NOS, obviously inhibited the U Ⅱ-induced NOS activation, NO production and cGMP formation. Conclusion: The results suggest that U Ⅱ can activate the vascular NOS/NO pathway, increasing tissue NO production and cGMP content.
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AIM: To investigate the effect of endothelin (ET), angiotensin II (AngII) and homocysteine (Hcy) on C-type natriuretic peptide (CNP) synthesis and release. METHODS: Human endothelial cell was cultured; CNP was measured by radioimmunoassay method. RESULTS: ET and AngII could augment CNP synthesis in human endothelial cells. Compared with control group, 10-9,10-8,10-7 mol/L ET and Ang II increased CNP content of endothelial cells by 1%(P＞0.05), 49%(P＜0.05),117%(P＜0.01) and 137% (P＜0.01),165%(P＜0.01),201%(P＜0.01),respectively. A great dose of ET and Ang II also stimulated CNP release from cultured human endothelial cells. Hcy had no effect on CNP synthesis, but 10-9，10-8,10-7 mol/L Hcy enhanced CNP release from cultured human endothelial cells by 17%(P＞0.05),84%(P＜0.01) and 555%(P＜0.01), respectively. CONCLUSION: ET, AngII and Hcy might be involved in the synthesis and release of human endothelial cell CNP.
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AIM: To investigate the effect of basic fibroblast growth factor (bFGF) on C-type natriuretic peptide (CNP) production, release and mRNA expression. METHODS: Human endothelial cell cultured; CNP was measured by radioimmunoassay method;CNP mRNA expression was determined by RT-PCR technique. RESULTS: bFGF could augment CNP synthesis in human endothelial cells. Compared with control group,25 ng, 50 ng, 100 ng bFGF increased CNP contents in endothelial cells by 88% (P
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AIM: To observe the changes of cystathionine-lyase/hydrogen sulfide(CSE/H_2S) in vivo in vascular calcification and to explore the role of CSE/H_2S in vascular calcification.METHODS: Vascular calcification model in rats was induced by administration of vitamin D_3 plus nicotine.The extent of calcification was estimated by assaying calcium content.[~(45)Ca~(2+)] deposition and alkaline phosphatase(ALP) activity were detected.CSE mRNA amount was determined by using competitive quantitative RT-PCR.The content of H_2S and activity of CSE in the plasma and cardiovascular tissues were also determined with biochemical methods.RESULTS: Calcium content in myocardium increased by 3.8 folds in a calcification model.Compared to control,calcium content,[~(45)Ca~(2+)] accumulation and ALP activity in calcified arteries increased by 6.8,1.4,and 1.9 folds,respectively(P
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] AIM: Lysophosphatidic acid (LPA) is a bioactive phospholipid known to have growth factor-like activity on fibroblasts, and is involved in cardiovascular diseases. Besides direct effects, usually, LPA can work together with other bioactive factors to regulate cardiovascular homeostasis by induction of their expression and production, or increase in their activity. Among variety of bioactive factors, adrenomedullin (ADM) is a multifunctional peptide with an important cytoprotective effect against cardiovascular damage, but the interaction between ADM and LPA on adventitia remains unknown. METHODS: The experiment was performed on the bath of isolated rat aortic adventitia, ADM produced and secreted from adventitia stimulated by LPA was detected by using radioimmunoassay, proliferation in adventitia cells was evaluated by the level of [3H]-thymine incorporation, and prepro ADM gene expression was measured by semi-quantitative reverse transcriptase polymerase chain reaction. RESULTS: It was found that LPA stimulated aortic adventitia to secrete ADM and express its mRNA in a concentration-dependent manner. ADM inhibited LPA-induced proliferation in adventitial cells, and attenuated the activity of mitogen activated protein kinase (MAPK) stimulated by LPA. In contrast, the treatment with specific antagonists of ADM receptor potentiated the LPA-induced proliferation in adventitial cells. CONCLUSION: LPA stimulates adventitia to produce and secrete ADM, and in turn, ADM produced by adventitia regulates the vascular biological effects of LPA. [
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AIM: The activity and expression of neutral endopeptidase (NEP) and the adrenomedullin (ADM) contents in various tissues were observed in septic shock and control rats to study the possible role of NEP in the change of ADM contents in tissues during septic shock. METHODS: The septic shock model of rats were established by cecal ligation and puncture (CLP). ADM contents, NEP activities, level of NEP mRNA and NEP protein were measured. RESULTS: (1) In early septic shock (ES), the ADM contents were generally higher in detected tissues, the NEP activity in left ventricle and small intestine were lower and was higher in blood than those in controls, and in lung, kidney and aorta were similar with the controls. NEP immunoreactive staining were less in lung, left ventricle, endothelium and media of aorta, but more in adventitia of aorta and kidney than those of the controls; (2) In late septic shock (LS), the ADM contents in small intestine was less but in plasma and other tissues were higher, and the NEP activity were less in plasma and other tissues than those in ES. The NEP immunoreactive staining were less in heart, endothelium and media of aorta, lung and kidney than those in ES, and was no significant change in adventitia of aorta compared with those of ES. RT-PCR found that NEP gene expression were significantly less in left ventricle, aortas, lung and small intestine than those in the controls. CONCLUSIONS: In septic shock rats, the NEP activity changes heterogeneously but the ADM contents elevate in most tissues. These results indicate that during the septic shock, the local concentrations and actions of ADM in various tissues may be regulated differently by the NEP. [
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AIM: To explore the effects of angiotensin II on aortic calcification in the rat. METHODS: Arterial calcification of Sprague-Dawley rats was induced by vitamin D_3 plus nicotine. Calcification was confirmed by Von Kossa staining, measurement of calcium content, [~(45)Ca~(2+)] accumulation and alkaline phosphatase (ALP) activity of vascular tissue. RESULTS: The results showed that calcium content, [~(45)Ca~(2+)] accumulation and ALP activity in calcified arteries increased significantly compared with those of control. Ang Ⅱ levels in plasma and aortic tissues and the amount of angiotensinogen mRNA in calcified aorta were also increased as compared with control. Captopril (inhibitor of ACE) and losartan (Ang Ⅱ receptor inhibitor) decreased significantly the content of calcium, [~(45)Ca~(2+)] uptake and ALP activity in calcified aorta. Ang Ⅱ levels in plasma and aortic tissues and the amount of angiotensinogen mRNA in aortic tissue were down-regulated by captopril. The amount of angiotensinogen mRNA and the content of Ang Ⅱ in the calcified aorta were also decreased by losartan. CONCLUSION: The captopril and losartan significantly alleviate the vascular calcification. [
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AIM To investigate effect of urotensin Ⅱ (U Ⅱ )on proliferation of aorta smooth muscle cells (ASMC) of rat and study the signal transduction pathway of it. MEfHODS in cultured ASMC of rat, U Ⅱ was used to stimulate proliferation of these cells and levels of [3H]-TdR incorporation were used to evaluate the sped of DNA synthesis, and different inhibitors were ed to study the action of different signal transduction pathway of mitogenic effect of UⅡ on VSMC. RESULTS. 1 ? 10-9~l ? 10-7 mol. L-l U Ⅱ caused marked concentration-de pendent increasing of [3H]-TdR incorporation of ASMC [3H]-TdR incorporation of 1 ? 10-9, 1 ? 10-8 and １ ? 10-7 mol. L－l U Ⅱ were 22%'(P
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AIM: To investigate the effect of metallothionein(MT) on proliferation of rat vascular smooth muscle cells (VSMCs) stimulated by homocysteine and its mechanism. METHODS: VSMCs proliferation was measured by -TdR incorporation, mitogen-activated protein kinase(MAPK)activity were determined by immunoprecipitation method, the intracellular contents of MT and malondialdehyde (MDA)were assayed by [ 109 Cd]-hemoglobin saturation method and TBA reaction, respectively, and lactate dehydrogenase (LDH) leakage was measured by NADH oxidation. RESULTS: Hcy(10 -6 -10 -4 mmol/L) stimulated -TdR incorporation by the VSMCs in a concentration-dependent manner. Compared with control, -TdR incorporation in VSMCs treated with 0.1 mmol/L Hcy was increased by 4.2 fold ( P
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AIM: To observe the effect of adrenomedullin(ADM)on proliferation of vascular smooth muscle cells(VSMC) induced by urotensin Ⅱ(UⅡ). METHODS: DNA synthesis of cultured rat aortic VSMC was measured by -TdR incorporation. The activities of mitogen activated protein kinase(MAPK) were determined by isotope tagged with [?- 32 P]-ATP. RESULTS: UⅡ(10 -8 mol/L) significantly increased -TdR incorporation of VSMC and MAPK activities by 38%( P0.05 ), 32%( P0.05 ), 32%( P