Are there gender differences in left ventricular remodeling after myocardial infarction in rats?

Antônio, Ednei Luiz; Serra, Andrey Jorge; Santos, Almira Alves dos; Vieira, Stella Sousa; Silva, Jairo Montemor Augusto; Yoshizaki, Amanda; Sofia, Renato Rodrigues; Tucci, Paulo José Ferreira

doi:10.5935/1678-741.20140093

Cited by 9 publications

(10 citation statements)

References 31 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Several studies have shown that gender can be a key factor in cardiac remodeling post-MI and could be a risk factor for an unfavorable prognosis 22 , 23 . However, a study comparing male and female rats 6 weeks after MI showed no gender differences in morphological and functional abnormalities or in LV remodeling post-MI 24 . This experimental model has been widely accepted for studying post-MI LV remodeling and was the basis of our choice to use female rats in our study, in addition to their more frequent availability in our facilities.…”

Section: Discussionmentioning

confidence: 94%

Previous exercise training increases levels of PPAR-α in long-term post-myocardial infarction in rats, which is correlated with better inflammatory response

Santos¹,

Higuchi²,

Tucci³

et al. 2016

Clinics

View full text Add to dashboard Cite

OBJECTIVE:Exercise is a protective factor for cardiovascular morbidity and mortality, with unclear mechanisms. Changing the myocardial metabolism causes harmful consequences for heart function and exercise contributes to metabolic adjustment modulation. Peroxisome proliferator-activated receptors (PPARs) are also myocardium metabolism regulators capable of decreasing the inflammatory response. We hypothesized that PPAR-α is involved in the beneficial effects of previous exercise on myocardial infarction (MI) and cardiac function, changing the expression of metabolic and inflammatory response regulators and reducing myocardial apoptosis, which partially explains the better outcome.METHODS AND RESULTS:Exercised rats engaged in swimming sessions for 60 min/day, 5 days/week, for 8 weeks. Both the exercised rats and sedentary rats were randomized to MI surgery and followed for 1 week (EI1 or SI1) or 4 weeks (EI4 or SI4) of healing or to sham groups. Echocardiography was employed to detect left ventricular function and the infarct size. Additionally, the TUNEL technique was used to assess apoptosis and immunohistochemistry was used to quantitatively analyze the PPAR-α, TNF-α and NF-κB antigens in the infarcted and non-infarcted myocardium. MI-related mortality was higher in SI4 than in EI4 (25% vs 12%), without a difference in MI size. SI4 exhibited a lower shortening fraction than EI4 did (24% vs 35%) and a higher apoptosis/area rate (3.97±0.61 vs 1.90±1.82) in infarcted areas (both p=0.001). Immunohistochemistry also revealed higher TNF-α levels in SI1 than in EI1 (9.59 vs 4.09, p<0.001) in infarcted areas. In non-infarcted areas, EI4 showed higher levels of TNF-α and positive correlations between PPAR-α and NF-κB (r=0.75, p=0.02), in contrast to SI4 (r=0.05, p=0.87).CONCLUSION:Previously exercised animals had better long-term ventricular function post-MI, in addition to lower levels of local inflammatory markers and less myocardial apoptosis, which seemed to be related to the presence of PPAR-α.

show abstract

Section: Discussionmentioning

confidence: 94%

Previous exercise training increases levels of PPAR-α in long-term post-myocardial infarction in rats, which is correlated with better inflammatory response

Santos¹,

Higuchi²,

Tucci³

et al. 2016

Clinics

View full text Add to dashboard Cite

show abstract

“…The acute MI triggers an adverse process known as cardiac remodeling, in which there is left ventricular (LV) dilation and enlargement of the ischemic tissue (Serra and Tucci, 2016 ). Moreover, an impaired LV systolic and diastolic function and a reduced myocardial inotropism are well-documented findings (dos Santos et al, 2013 ; Antonio et al, 2015 ). Several mechanisms are shown to be implicated in cardiac remodeling, including adrenergic hyperactivity, renin-angiotensin-aldosterone system, apoptosis, autophagy, fibrosis, inflammation, oxidative stress, calcium handling abnormalities, and metabolic dysfunction (Whelan et al, 2010 ; Carlos et al, 2016 ; Ziff et al, 2016 ).…”

Section: Introductionmentioning

confidence: 90%

“…The MI was induced according to a well-established technique (Antonio et al, 2015 ). Briefly, under anesthesia and artificial ventilation (Harvard Rodent Ventilator, Model 863; Harvard Apparatus, Holliston, MA, USA), a left thoracotomy was performed.…”

Section: Methodsmentioning

confidence: 99%

Low-Level Laser Application in the Early Myocardial Infarction Stage Has No Beneficial Role in Heart Failure

et al. 2017

Self Cite

View full text Add to dashboard Cite

Low-level laser therapy (LLLT) has been targeted as a promising approach that can mitigate post-infarction cardiac remodeling. There is some interesting evidence showing that the beneficial role of the LLLT could persist long-term even after the end of the application, but it remains to be systematically evaluated. Therefore, the present study aimed to test the hypothesis that LLLT beneficial effects in the early post-infarction cardiac remodeling could remain in overt heart failure even with the disruption of irradiations. Female Wistar rats were subjected to the coronary occlusion to induce myocardial infarction or Sham operation. A single LLLT application was carried out after 60 s and 3 days post-coronary occlusion, respectively. Echocardiography was performed 3 days and at the end of the experiment (5 weeks) to evaluate cardiac function. After the last echocardiographic examination, LV hemodynamic evaluation was performed at baseline and on sudden afterload increases. Compared with the Sham group, infarcted rats showed increased systolic and diastolic internal diameter as well as a depressed shortening fraction of LV. The only benefit of the LLLT was a higher shortening fraction after 3 days of infarction. However, treated-LLLT rats show a lower shortening fraction in the 5th week of study when compared with Sham and non-irradiated rats. A worsening of cardiac function was confirmed in the hemodynamic analysis as evidenced by the higher LV end-diastolic pressure and lower +dP/dt and −dP/dt with five weeks of study. Cardiac functional reserve was also impaired by infarction as evidenced by an attenuated response of stroke work index and cardiac output to a sudden afterload stress, without LLLT repercussions. No significant differences were found in the myocardial expression of Akt1/VEGF pathway. Collectively, these findings illustrate that LLLT improves LV systolic function in the early post-infarction cardiac remodeling. However, this beneficial effect may be dependent on the maintenance of phototherapy. Long-term studies with LLLT application are needed to establish whether these effects ultimately translate into improved cardiac remodeling.

show abstract

“…The area shortening was determined by the formula: Delta Areas = (AD - AS)/AD x 100, 17 in which AD and AS are the areas in the diastole and systole, respectively. The fractional area shortening has been shown to be effective in detecting left ventricular systolic dysfunction in experimental models of myocardial infarction in rats 18-20 and has the advantage of considering the two-dimensional image of the short axis of the left ventricle, compared with the ventricular shortening fraction (ΔD%), which takes into account only a linear ventricular dimension in the diastole and systole.…”

Section: Methodsmentioning

confidence: 99%

Comparison between Radionuclide Ventriculography and Echocardiography for Quantification of Left Ventricular Systolic Function in Rats Exposed to Doxorubicin

Oliveira

O’Connell

Carvalho

et al. 2016

Arquivos Brasileiros De Cardiologia

View full text Add to dashboard Cite

BackgroundRadionuclide ventriculography (RV) is a validated method to evaluate the left ventricular systolic function (LVSF) in small rodents. However, no prior study has compared the results of RV with those obtained by other imaging methods in this context.ObjectivesTo compare the results of LVSF obtained by RV and echocardiography (ECHO) in an experimental model of cardiotoxicity due to doxorubicin (DXR) in rats. MethodsAdult male Wistar rats serving as controls (n = 7) or receiving DXR (n = 22) in accumulated doses of 8, 12, and 16 mg/kg were evaluated with ECHO performed with a Sonos 5500 Philips equipment (12-MHz transducer) and RV obtained with an Orbiter-Siemens gamma camera using a pinhole collimator with a 4-mm aperture. Histopathological quantification of myocardial fibrosis was performed after euthanasia.ResultsThe control animals showed comparable results in the LVSF analysis obtained with ECHO and RV (83.5 ± 5% and 82.8 ± 2.8%, respectively, p > 0.05). The animals that received DXR presented lower LVSF values when compared with controls (p < 0.05); however, the LVSF values obtained by RV (60.6 ± 12.5%) were lower than those obtained by ECHO (71.8 ± 10.1%, p = 0.0004) in this group. An analysis of the correlation between the LVSF and myocardial fibrosis showed a moderate correlation when the LVSF was assessed by ECHO (r = -0.69, p = 0.0002) and a stronger correlation when it was assessed by RV (r = -0.79, p < 0.0001). On multiple regression analysis, only RV correlated independently with myocardial fibrosis.ConclusionRV is an alternative method to assess the left ventricular function in small rodents in vivo. When compared with ECHO, RV showed a better correlation with the degree of myocardial injury in a model of DXR-induced cardiotoxicity.

show abstract

Are there gender differences in left ventricular remodeling after myocardial infarction in rats?

Cited by 9 publications

References 31 publications

Previous exercise training increases levels of PPAR-α in long-term post-myocardial infarction in rats, which is correlated with better inflammatory response

Previous exercise training increases levels of PPAR-α in long-term post-myocardial infarction in rats, which is correlated with better inflammatory response

Low-Level Laser Application in the Early Myocardial Infarction Stage Has No Beneficial Role in Heart Failure

Comparison between Radionuclide Ventriculography and Echocardiography for Quantification of Left Ventricular Systolic Function in Rats Exposed to Doxorubicin

Contact Info

Product

Resources

About