Effects Of Valsartan And Spironolactone On Matrix Metalloproteinases, Collagen Metabolism And Heart Function In Post-myocardial Infarction

The left ventricular(LV) remodeling after myocardial infarction can lead to progressive dilation and eventually pump dysfunction. The summation of cellular and extracellular events that occur in the post myocardial infarction period results in changes in LV geometry and has been called "infarct expansion". However, the mechanism responsible for left ventricular remodeling in heart failure progression is unclear. How to prevent and improve LV remodeling and cardiac function after AMI and long term prognosis are catching more and more attention. Left ventricular remodeling after myocardial infarction (MI) involves the hypertrophic growth of cardiomyocytes and the accumulation of fibrillar collagen in the interstitial space. Past studies have demonstrated that a structural determinant of infarct expansion is extrallcellular remodeling. The integrity of the original extrallcellular matrix (ECM) is thought to play an important role in determining the extent of remodeling after MI. The matrix metalloproteinases (MMPs) are an family of enzymes which contribute to extracellular matrix degradation. The MMPs and their tissue inhibitors co-regulate the metabolism of the extracellular matrix, and play an important role in the myocardial extracellular matrix and LV remodeling. However, exogenous MMP inhibition on infarct expansion remains unknown. A substantial amount of experiment and clinical data now exist support the pivotal role of the RAAS in contributing to left ventricular (LV) remodeling. Angiotension II is formed locally within the myocardium and stimulates collagen production and proliferation of cardiac fibroblasts. Studies showed the combining of angiotension converting enzyme inhibitor (ACEI) with angiotension type 1(AT1) receptor antangonist resulted in slightly greater effect in limiting collagen deposition. Aldosterone is another component of the RAAS that may significantly contribute to development of adverse ventricular remodeling in patients with LV systolic dysfunction independent of effects of angiotensionⅡ. In vitro, aldosterone induces an increase in collagen synthesis by cardiac fibroblasts. RALES proved that spironolactone had showed significant effect in the treatment of patient with CHF, mortality of CHF was reduced by 30 percent, and the mechanism of survival benefit was related to inhibite cardiac fibrosis. It is found that AT1 receptor blockade affects collagen deposition and not clear whether it affects MMPs activity. Whether spironolactone affect collagen deposition and MMPs activity remain unknown. The aim of the study is to investigate the effect of AT1 receptor blockade-valsartan on inhibiting MMPs activity and collagen deposit and heart function improvement , and to evaluate the effect on ventricular aneurysm in post-myocardial infarction. The methods and results of the present study are as follows: PartⅠEffect of valsartan and spironolactone on the expression of MMPs in post myocardial infarction Objective: MMPs play an important role in left ventricular remodeling, The inhibition of MMPs may contribute to improve the LV remodeling.The study examined the effects of valsartan, spironolactone and combination therapy on the expression of MMPs mRNA in post myocardial infarction. Methods: we established the left ventricular infarct in rats by ligation of the left anterior descending coronary artery. 140 healthy male Sprague Dawley rats (12-15 weeks and 210-260g) in this study were divided into sham group( water, 2ml·d^-1 in drinking, 24 ),control group (water, 2ml·d^-1 in drinking,24) ,Valsartan group ( val, valsartan 30mg·kg^-1·d^-1 , 24) ,Spironolactone group (spi, spironolactone 20mg·kg^-1·d^-1,24) and VS group (VS, valsartan 30mg·kg^-1·d^-1+spironolactone 20mg·kg^-1·d^-1,24 ). RT-PCR was used to observe the gene expression of MMP-2 and MMP-9. The MMP-2 and MMP-9 protein were quantified by immunohistochemical method. Results: 1) MMP-2 and MMP-9 mRNA levels were significantly higherin control group than those in sham group at 1,2,3 week(sP<0.05)(in control group at 3 weeks MMP-2, MMP-9 mRNA level was 0.67±0.03,0.74±0.03). 2) In comparison with control groups, the gene expression of MMP-2 and MMP-9mRNA in valsartan group(at 3 weeks MMP-2, MMP-9mRNA was 0.58±0.04, 0.66±0.03) and VS group(at 3 weeks MMP-2, MMP-9mRNA was 0.56±0.04, 0.64±0.02) were decreased significantly(P<0.05)3) No significantly differences in the gene expression of MMP-2 and MMP-9 were found for the valsartan group as compared with the VS group(all P>0.05); The gene expression of MMP-2 and MMP-9 were lower in valsartan group and VS group than those in spironolactone group(P<0.05). 4) ①In comparison with control group, the optical density score of MMP-2 and MMP-9 in valsartan group ( at 3 weeks the score of MMP-2, MMP-9 was 4.83±0.03, 5.08±0.14) and VS group ( at 3 weeks the score of MMP-2, MMP-9 was 4.83±0.03, 5.08±0.14) were decreased significantly (P<0.05), but no significantly difference was found between spironolactone group and control group(P>0.05). ②There were no difference in the optical density scores of MMP-2 and MMP-9 between valsartan group and VS group(P>0.05), but the optical density scores were significantly lower in these two group than those in spironolactone group (P>0.05). Conclusions: MMP-2 and MMP-9 mRNA and protein levels were significantly higher in control group than in sham group. They were inhibited by valsartan and VS. There was no significant difference between valsartan groups and VS group, Combining of valsartan and spironolactone was better than monotherapy. Part ⅡEffect of valsartan and Spironolactone on collagen metabolism in post myocardial infarction Objectives: This study was to investigate the effects of valsartan, spironolactone and combination therapy on collagen metabolism in post myocardial infarction by measuring the content of collagen and the ratio of type Ⅰand Ⅲcollagen. Methods: It was as same as Part Ⅰin production of AMI in rats,groups randomly divided and treated. We measured the content of collagen and the ratio of type Ⅰand Ⅲcollagen at 1, 2, 3 week. Results: 1. In comparison with control group collagen contents and the ratio of type Ⅰand Ⅲcollagen were reduced significantly(P<0.05)at 2, 3 week in infarct areas in valsartan group(at 3 week respectively 19.9%, 18.6%). In comparison with control group, collagen contents and the ratio of type Ⅰand Ⅲcollagen were reduced significantly (at 3 week respectively 19.5%, 17.3%)(P<0.05)in infarct areas in spironolactone group at 3 week, and those parameters were reduced significantly(P<0.05-0.01)in infarct areas in VS groups at 2, 3 week (at 3 week respectively 39.3%, 32%). At 3 week, collagen contents and the ratio of type Ⅰand Ⅲcollagen in VS group were lower significantly than those in valsartan group and spironolactone group (P<0.05-0.01) 2. In comparison with control group, collagen contents and the ratio of type Ⅰand Ⅲcollagen were reduced significantly(P<0.05)at 2, 3 weeks in non-infarct areas in valsartan group (at 3 week respectively 28.6%, 22.6%) and those parameters were reduced significantly ( P<0.05 ) in non-infarct areas in spironolactone group (at 3 week respectively 25%, 21%) at 3 week, and those were reduced significantly(P<0.05-0.01)in non-infarct areas in VS group at 2, 3 weeks (at 3 week respectively 42%,41.9%). Those parameters were lower in non-infarct areas in VS group(P<0.05)than in valsartan group or spironolactone group. Conclusions: Valsartan reduced the content of collagen and the ratio of type Ⅰand Ⅲcollagen in infarct and non-infarct areas. Spironolactone reduced the collagen content and type Ⅰ/Ⅲcollagen ratio in infarct and non-infarct areas later than valsartan and combination therapy. Combining valsartan with spironolactone were more effective than monotherapy. Part ⅢEffects of valsartan and Spironolactone on hemodynamic and LV remodeling in post myocardial infarction Objectives: To evaluate the effects of valsartan and spironolactone on LV remodeling and hemodynamic by measuring ventricular weight parameters and hemodynamic parameters.Methods: The production of AMI in rats and division of groups were as same as Part 1 . LVSP,LVEDP,+dp/dt and -dp/dt were measured by multi-lead physiological instrument at 1, 2, 3 weeks. Left ventricular weight and right ventricular weight were measured, and weight index were calculated. Results: 1). There were no significant differences in AOSP and AODP in valsartan group and spironolactone group as compared with those of control group. At 2,3 weeks, AOSP and AODP in VS group were decreased significantly(P<0.05)in comparison with control group. 2). At 1,2,3 weeks, LVEDP in valsartan group were decreased significantly(at 3 weeks decreased 41%)(P<0.05)in comparison with control group; LVEDP in valsartan group was lower than that in spironolactone group(P<0.05). 3). In comparison with control group, +dp/dt and -dp/dt were increased significantly respectively(P<0.05)in valsartan group and in VS group; At 2, 3 weeks, +dp/dt and -dp/dt in valsartan group were higher than those in spironolactone group(P<0.05). At 2, 3 weeks, +dp/dt,-dp/dt in VS group were significantly higher than those in spironolactone group and valsartan group(P<0.05). 4) ①In comparison with control group, the ventricular weight parameters were decreased significantly (P<0.05)in valsartan group at 2 and 3 week(at 3 weeks LVW, LVRW decreased 7%, 24%). In comparison with control group, the ventricular weight parameters were decreased significantly in spironolactone group at 3 week (P<0.05). In comparison with control group, the ventricular weight parameters were decreased significantly in VS group (at 3 weeks LVW, LVRW decreased 10.3%, 32%)(P<0.05). ②In comparison with spironolactone group, RVW and RVRW were decreased significantly respectively(P<0.05)in valsartan group. The ventricular weight parameters in VS group were lower significantly than those in spironolactone group(P<0.05). Conclusions: Valsartan reduced LVEDP, improved heart function and reduced ventricular weight and LV weight index. Combining of valsartan and spironolactone were better in improving ventricular weight parameters andhemodynamic than Valsartan or Spironolactone. In comparison with Valsartan,. Spironolactone reduced ventricular weight and LV weight index more slowly. Part ⅣThe effects of valsartan and spironolactone on collagen metabolism and heart function in patients after acute myocardial infarction with aneurysm Objective: To evaluate the effects of valsartan and spironolactone on collagen metabolism and heart function in patients after acute myocardial infarction by measuring serum PⅢNp and PⅠCP level and echocardiaography . Methods: The patients of first anterior AMI with LVA proven by left ventriculography were divided into Valsartan-and-Spironolactone group (VS group, 36 cases, male 31/female 5, average age 54.36±6.42 years), Valsartan group(34cases, male 30/female 4, average age 53.16±5.54 years). Serum PⅢNp and PⅠCP were measured at 1,2,12 week after onset of AMI. At 2,12 weeks after onset of AMI, the parameters of left ventricular end diastolic volume index(LVEDVI), left ventricular end systolic volume index(LVESVI), left ventricular ejection fraction(LVEF) and regional wall movement index(RWMI) were measured. Results: 1 There was no difference between the two groups in clinical characteristic such as age, sex, risk factors (include history of smoking, hypertension, diabetes, hyperlipidemia), heart function and the interval time of onset to reperfusion. 2 At 1, 2 weeks, there was no difference in serum PⅢNP and PⅠCP between the two groups. At 12 weeks, serum PⅢNP and PⅠCP in Valsartan-and-Spironolactone group were lower significantly than those in Valsartan group (VS group PⅢNP, PⅠCP was 4.38±1.39,98.41±16.24;Val group PⅢNP, PⅠCP was 5.28±1.62,106.36±18.29) (P<0.05). 3 Analyses of echocardiaographic data: ①At 12 week LVEF in VS group was significantly increased 4.81%(P<0.05) while other parameters were decreased significantly (P<0.05) as compared with those in Valsartan group②At 12 week LVEF and VE/VA in both group was significantly higher while other...