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Updated: Mar 9, 2026
LAD-Ligation: A Murine Model of Myocardial Infarction
Published on: October 14, 2009
Epac-Rap1-activated mesenchymal stem cells improve cardiac function in rat model of myocardial infarction
Irfan Khan1, Anwar Ali1, Muhammad Aleem Akhter1
1Dr. Panjwani Center for Molecular Medicine and Drug Research, International Center for Chemical and Biological Sciences, University of Karachi, Karachi, Pakistan.
Introduction:
Rap1, a member of Ras superfamily of small GTP-binding proteins, is involved in cardiovascular biology in numerous ways. It is an evolutionary conserved regulator of adhesion, polarity, differentiation and growth.
Aims:
Our aim was to analyze Rap1-activated rat bone marrow mesenchymal stem cells (MSCs) for their potential role in adhesion and cardiac differentiation.
Methods:
Myocardial infarction (MI) was produced in Sprague Dawley (SD) rats through occlusion of the left anterior descending coronary artery. MSCs were treated with 8-pCPT-2'-O-Me-cAMP (CPT) to activate Rap1. Normal (untreated) and CPT-treated MSCs were transplanted through intramyocardial injection in respective groups. Cardiac function was assessed by echocardiography at 2 and 4 weeks after cell transplantation. Histological analysis was performed to observe changes at tissue level.
Results:
Homing of CPT-treated MSCs was significantly (***P<.001) higher as compared to normal MSCs in the infarcted hearts. This may be due to increase in the gene expression of some of the cell adhesion molecules as evident by qRT-PCR analysis. Significant (***P<.001) improvement in the restoration of heart function in terms of left ventricular diastolic and systolic internal diameters (LVIDd, LVIDs), % ejection fraction, % fraction shortening and end-systolic and end-diastolic volumes were observed in CPT-treated MSCs as compared to the MI model. Histological analyses showed significant (***P<.001) reduction in scar formation in the CPT-treated group. Differentiation of treated MSCs into functional cardiomyocytes was evident through immunohistochemical staining. LV wall thickness was also preserved significantly (***P<.001). Blood vessel formation was more pronounced in CPT-treated group although both cell therapy groups showed significant increase as compared to MI model.
Conclusion:
Our findings showed that pharmacological activation of Epac-Rap1 improves cardiac function through better survival, adhesion and differentiation of transplanted cells. Transplantation of these MSCs in the infarct area restored functional myocardium.
Insights
Pharmacological activation of Epac-Rap1 enhances mesenchymal stem cell (MSC) adhesion and cardiac differentiation. This improved cell survival and function after transplantation, restoring heart function and reducing scar tissue in a rat myocardial infarction model.
Area of Science:
- Cardiovascular Biology
- Stem Cell Therapy
- Regenerative Medicine
Background:
- Rap1, a small GTP-binding protein, plays a crucial role in cardiovascular biology, regulating cell adhesion, polarity, differentiation, and growth.
- Understanding Rap1's role is key to developing novel therapeutic strategies for cardiac repair.
Purpose of the Study:
- To investigate the potential of Rap1-activated rat bone marrow mesenchymal stem cells (MSCs) in promoting adhesion and cardiac differentiation.
- To evaluate the therapeutic efficacy of Rap1-activated MSCs in a myocardial infarction model.
Main Methods:
- Myocardial infarction (MI) was induced in Sprague Dawley rats.
- Mesenchymal stem cells (MSCs) were treated with 8-pCPT-2'-O-Me-cAMP (CPT) to activate Rap1.
- CPT-treated and untreated MSCs were transplanted into infarcted rat hearts, with cardiac function assessed via echocardiography and histology.
Main Results:
- CPT-treated MSCs exhibited significantly higher homing to infarcted hearts, potentially due to increased expression of cell adhesion molecules.
- Transplantation of CPT-treated MSCs led to significant improvements in cardiac function, including enhanced ejection fraction and reduced scar formation.
- Histological analysis revealed differentiation of treated MSCs into cardiomyocytes, preserved left ventricular wall thickness, and increased blood vessel formation.
Conclusions:
- Pharmacological activation of Epac-Rap1 enhances the survival, adhesion, and differentiation of transplanted MSCs.
- Rap1-activated MSC transplantation effectively restores cardiac function and myocardial tissue in a post-MI setting.
- This approach holds promise for regenerative therapy in cardiovascular diseases.
