Related Experiment Videos
Cardiovascular disease
1National Heart and Lung Institute, Imperial College of Science, Technology and Medicine, Royal Brompton Hospital, London, UK.
Insights
Gap junctions are vital for heart and artery function. Abnormalities in connexin43 (Cx43) gap junctions contribute to heart disease and atherosclerosis by affecting cell communication and electrical impulse spread.
Area of Science:
- Cardiovascular Biology
- Cellular Physiology
- Molecular Medicine
Background:
- Gap junctions mediate electrical impulse spread in the heart for synchronized contraction.
- They coordinate function between arterial wall cells.
- Altered gap junctional coupling is linked to arrhythmia and cardiovascular disease.
Purpose of the Study:
- To explore the role of gap junctions in cardiovascular health and disease.
- To investigate connexin expression and distribution in cardiac and arterial tissues.
- To understand how gap junction abnormalities contribute to conditions like arrhythmia and atherosclerosis.
Main Methods:
- Analysis of connexin expression (Cx43, Cx40, Cx37) in cardiac and arterial tissues.
- Examination of gap junction distribution at infarct borders.
- Correlation of connexin levels with disease states like atherosclerosis and response to injury.
Main Results:
- Myocardial gap junction abnormalities (distribution, reduced Cx43) at infarct borders may cause heterogeneous wavefront propagation and lowered conduction velocity, precipitating arrhythmia.
- Endothelial cells express Cx40, Cx37, and sometimes Cx43; medial smooth muscle cells express Cx43.
- Increased Cx43 in medial smooth muscle cells is associated with phenotypic transformation in atherosclerosis and arterial injury response.
Conclusions:
- Gap junctions are crucial for cell-to-cell signaling in vessel walls and impulse conduction in the heart.
- Aberrant gap junction function and connexin expression are implicated in the pathogenesis and clinical manifestations of cardiovascular diseases.
- Targeting gap junctions may offer therapeutic strategies for heart and arterial diseases.
Abstract:
Gap junctions play essential roles in the normal function of the heart and arteries, mediating the spread of the electrical impulse that stimulates synchronized contraction of the cardiac chambers, and contributing to co-ordination of function between cells of the arterial wall. Altered gap junctional coupling is implicated in the genesis of arrhythmia, a major cause of death in heart disease. Two abnormalities in myocardial gap junctions distribution at the border zone of infarcts and reduced levels of connexin43 (Cx43; alpha 1)--may lead to heterogeneous wavefront propagation and lowered conduction velocity, key factors that precipitate arrhythmia. In the major arteries, endothelial cells express Cx40 (alpha 5) and Cx37 (alpha 4) and, in some instances, also Cx43, whereas underlying medial smooth muscle cells express only Cx43. Increased Cx43 expression between medial smooth muscle cells is intimately linked to phenotypic transformation to the synthetic state in both early human coronary phenotypic transformation to the synthetic state in both early human coronary atherosclerosis, and in the response of the arterial wall to injury. The accumulating evidence suggests that gap junctions in both their guises--as pathways for cell-to-cell signalling in the vessel wall and as pathways for impulse conduction in the heart--may have key roles in the initial pathogenesis and eventual clinical manifestation of human cardiovascular disease.