an-experimental-model-myocardial-infarction-for-studying-cardiac

An Experimental Model of Myocardial Infarction for Studying Cardiac Repair and Remodeling in Knockout Mice

Cardiovascular disease is the most prevalent cause of death in Western countries, with acute myocardial infarction (MI) being the most prevalent form. ...

Universidad de Buenos Aires

Galectin-3 is essential for early wound healing and ventricular remodeling after myocardial infarction in mice.

We aimed to investigate the role of early administration of Enalapril (Enal) on post-myocardial infarction (MI) ventricular remodeling and diastolic dysfunction in rabbits. White New Zealand rabbits that underwent coronary artery ligature or Sham were divided in three experimental groups: (1) Sham, (2) MI, and (3) MI+Enal. Enal was given by gavage at a dose of 10mg/kg/day starting at 3h after surgery for 35days. At the end of the protocol, we measured (1) mean arterial pressure, (2) left ventricular (LV)+dP/dtmax, (3) LV end-diastolic pressure (LVEDP) and isovolumic relaxation (Tau), (4) LV dimensions, (5) LV ejection and shortening fraction, (6) infarct size (Masson's trichrome-stained slices), (7) fibrosis in the infarct and remote zone (Picrosirius red-stained slices), and (8) myocyte cross-sectional area (MCSA) in WGA-stained section. Enal reduced the mean arterial pressure by 30% as compared with untreated animals and Sham (P<.05). MI reduced LV+dP/dtmax and LV-dP/dtmax (mmHg/s), increased LVEDP (mmHg), Tau (ms), and t50 (ms) values, suggesting a decrease in the relaxation rate. LV end-diastolic dimension and LV end-systolic dimension (LVESD, mm) increased in untreated MI (P<.05 vs. Sham). In contrast, Enal markedly prevented post-MI diastolic dysfunction by significantly decrease LVEDP from 8.2±0.2 to 5.1±0.3mmHg, Tau from 19.8±0.8 to 15.3±0.9ms, and t50 from 12.4±0.5 to 9.6±0.8ms as well as reduced LVESD from 15±1.1 to 12±0.8mm (P<.05 MI vs. MI+Enal). Collagen concentration in the scar was unaffected, but chronic treatment with Enal prevented myocardial fibrosis and MCSA in the remote zone. In summary, chronic early administration of Enal to rabbits with experimental MI has a favorable effect on ventricular remodeling and diastolic function by reducing MCSA and fibrosis, without affecting the wound healing.

Early administration of Enalapril prevents diastolic dysfunction and ventricular remodeling in rabbits with myocardial infarction.

We studied the role of galectin-3 (Gal-3) in the expression of alternative activation markers (M2) on macrophage, cytokines, and fibrosis through the temporal evolution of healing, ventricular remodeling, and function after myocardial infarction (MI). C57BL/6J and Gal-3 knockout mice (Lgals3) were subjected to permanent coronary ligation or sham. We studied i) mortality, ii) macrophage infiltration and expression of markers of alternative activation, iii) cytokine, iv) matrix metalloproteinase-2 activity, v) fibrosis, and vi) cardiac function and remodeling. At 1 week post-MI, lack of Gal-3 markedly attenuated F4/80+ macrophage infiltration and significantly increased the expression of Mrc1 and Chil1, markers of M2 macrophages at the MI zone. Levels of IL-10, IL-6, and matrix metalloproteinase-2 were significantly increased, whereas tumor necrosis factor-α, transforming growth factor-β, and fibrosis were remarkably attenuated at the infarct zone. In Gal-3 knockout mice, scar thinning ratio, expansion, and cardiac remodeling and function were severely affected from the onset of MI. At 4 weeks post-MI, the natural evolution of fibrosis in Gal-3 knockout mice was also affected. Our results suggest that Gal-3 is essential for wound healing because it regulates the dynamics of macrophage infiltration, proinflammatory and anti-inflammatory cytokine expression, and fibrosis along the temporal evolution of MI in mice. The deficit of Gal-3 affected the dynamics of wound healing, thus aggravating the evolution of remodeling and function.

Genetic Deletion of Galectin-3 Alters the Temporal Evolution of Macrophage Infiltration and Healing Affecting the Cardiac Remodeling and Function after Myocardial Infarction in Mice.

Pablo Cassaglia

Instituto de Fisiopatología Cardiovascular,
Instituto de Fisiopatologia Cardiovascular,
Facultad de Medicina,
Instituto de Fisiopatologia Cardiovascular, Facultad de Medicina

Universidad de Buenos Aires

An Experimental Model of Myocardial Infarction for Studying Cardiac Repair and Remodeling in Knockout Mice

Pablo Cassaglia

Instituto de Fisiopatología Cardiovascular,Instituto de Fisiopatologia Cardiovascular,Facultad de Medicina,Instituto de Fisiopatologia Cardiovascular, Facultad de Medicina

Universidad de Buenos Aires

An Experimental Model of Myocardial Infarction for Studying Cardiac Repair and Remodeling in Knockout Mice

Instituto de Fisiopatología Cardiovascular,
Instituto de Fisiopatologia Cardiovascular,
Facultad de Medicina,
Instituto de Fisiopatologia Cardiovascular, Facultad de Medicina