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Published on: September 10, 2015
Impairment of sarcolemmal permeability in the acute ischemic myocardium--a study with ionic lanthanum probe method
1Third Department of Internal Medicine, Showa University School of Medicine, Tokyo, Japan.
Insights
Early detection of heart cell damage is possible. Lanthanum (La3+) ion probe shows increased sarcolemmal permeability in ischemic myocardial cells before irreversible changes occur, aiding in understanding heart injury.
Area of Science:
- Cardiovascular Science
- Cell Biology
- Pathology
Background:
- Acute ischemic myocardial injury is a major cause of heart disease.
- Understanding early cellular changes is crucial for effective treatment.
- Sarcolemmal integrity is vital for myocyte function.
Purpose of the Study:
- To investigate early changes in sarcolemmal permeability during acute ischemic myocardial injury.
- To utilize lanthanum (La3+) as a probe to assess membrane integrity.
- To correlate lanthanum deposition with ultrastructural alterations in myocytes.
Main Methods:
- Induction of acute myocardial ischemia in dogs by ligating the left anterior descending coronary artery.
- Application of an ionic lanthanum (La3+) probe.
- Examination of cardiac myocytes using electron microscopy to detect La3+ deposition and structural changes.
Main Results:
- In normal myocytes, La3+ was confined to the extracellular space.
- Within 30 minutes of ischemia, 22% of subendocardial myocytes showed La3+ deposition in the cytosol.
- La3+ deposition increased with ischemia duration, preceding recognized necrotic changes at 60 minutes.
Conclusions:
- Lanthanum deposition precedes irreversible morphologic alterations in ischemic myocardial cells.
- Increased sarcolemmal permeability occurs early in ischemic injury.
- This suggests enhanced permeability to Ca2+ and degradation of plasma membrane integrity.
Abstract:
Impairment of sarcolemmal permeability after the initiation of acute ischemic myocardial injury was studied using an ionic lanthanum (La3+) probe in electron microscopy. Acute ischemic myocardium was induced by ligation of the left anterior descending coronary artery in dogs. In normal cardiac myocytes La is localized exclusively in the extracellular space. i.e. on the glycocalyx, in the T-system and in intercalated discs, with normal fine structures. In ischemic myocardial cells, La deposits were found in the cytosolic space in 22% of subendocardial cells with mild to moderate, but non-necrotic, fine structural changes as early as 30 min. The number of myocytes with La deposition increased with advancing ischemic injury, and necrotic fine structural changes were recognized following ischemia for 60 min. These results indicate that deposition of La occurs before the appearance of irreversible morphologic alterations in ischemic myocardial cells, and suggest an increased permeability of the sarcolemma for Ca2+ and the development of degradation of plasma membrane integrity.
