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Scanning electron microscopic studies on microvascular architecture of human coronary vessels by corrosion casts:
Insights
Scanning electron microscopy revealed the intricate microvascular architecture of the healthy human heart. In areas of focal necrosis, dilated and tortuous capillaries were observed, differing from normal myocardial vessels.
Area of Science:
- Cardiovascular Anatomy
- Microcirculation Research
- Pathological Morphology
Background:
- Understanding the microvascular architecture is crucial for comprehending cardiac function and disease.
- Previous studies have provided insights into coronary vasculature, but detailed analysis of the human ventricular wall's microcirculation, especially in pathological conditions, remains important.
Purpose of the Study:
- To investigate the microvascular architecture of the normal human heart's left ventricular posterior wall.
- To characterize the vascular changes associated with myocardial focal necrosis using scanning electron microscopy.
Main Methods:
- Corrosion casting of the left ventricular posterior wall from human hearts.
- Scanning electron microscopy (SEM) to visualize the microvascular network.
- Light microscopy for cross-sectional analysis of necrotic areas.
Main Results:
- Normal human heart: Arterioles smoothly connected to capillary plexuses; capillaries formed a dense, net-like architecture (5-7 micron diameter) with bifurcations and anastomoses.
- Observed arterio-venous and two types of venous-venous anastomoses in the normal left ventricular posterior wall.
- Focal necrosis sites: Characterized by numerous dilated, tortuous capillaries and small arterial branches, contrasting with normal vessels.
Conclusions:
- The study details the complex microvascular network in the normal human ventricular myocardium.
- Myocardial focal necrosis is associated with significant dilation and tortuosity of capillaries and small arteries.
- SEM of corrosion casts is effective for visualizing microvascular alterations in myocardial pathology.
Abstract:
Microvascular architecture of the normal human heart and myocardial focal necrosis were studied by scanning electron microscopy of corrosion casts. Casts macroscopically identical in form to the left ventricular posterior wall were prepared. The following results were obtained in the normal human heart. Most of the arterioles communicated with capillary plexuses smoothly and straightforwardly in the left ventricular posterior free wall. Arterioles which branched from the arteries ran in various directions and continued into capillaries either at right angles or obliquely in the trabeculae carneae. Capillaries running parallel with the cardiac muscle fibers ran in different directions to cross over with each other in different layers of myocardium. Capillaries in the myocardium formed a continuous and coarse net-like architecture with many bifurcations and anastomoses. Capillaries were about 5-7 micron in diameter. Some veins gathering capillaries in the epicardium ran into the myocardium and the others ran in the epicardium. Veins connecting with capillaries in the myocardium ran in the myocardial layer and communicated with larger veins. An arterio-venous anastomosis and two different types of venous-venous anastomoses were observed in the left ventricular posterior wall. At the site of focal necrosis, cross sections of dilated vessels were observed in large numbers by light microscopy and scanning electron microscopy. At the site of focal necrosis, dilated capillaries running with tortuosity were seen in large numbers by scanning electron microscopy of corrosion casts. When compared with vessels in the normal myocardium, small arterial branches were dilated and run tortuously. These dilated capillary plexuses were observed in the area which communicated with twigs branching off at the right angle from the arterial branch.