The role of endothelial gap junctions in the enlargement of chronic subdural hematomas

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✓ The structure of macrocapillaries (also called “sinusoids”) in the outer membrane of chronic subdural hematomas was investigated by electron microscopy, with particular attention paid to vascular permeability. One characteristic of macrocapillaries is the frequent formation of gap junctions between adjacent endothelial cells. In endothelial gap junctions 0.6 to 8 µm in diameter, numerous blood components, including red blood cells and plasma, can be seen squeezing or spilling into the interstitial space of the outer membrane. Irregularly deformed erythrocytes are located around the macrocapillaries, and amorphous material is seen among scattered thin collagen fibers. It is suggested that endothelial gap junctions of macrocapillaries play an important role in the leakage of blood, causing enlargement of chronic subdural hematomas.

Article Information

Address reprint requests to: Tetsumori Yamashima, M.D., Department of Neurosurgery, University of Kanazawa School of Medicine, Takaramachi 13–1, Kanazawa City, 920, Japan.

© AANS, except where prohibited by US copyright law.

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Figures

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    Light micrograph of a macrocapillary showing a laceration of its endothelial walls, which has been plugged by fibrinoid material 50 µm in diameter. H & E, × 230.

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    Electron micrograph showing an erythrocyte spilling through an endothelial gap junction 0.6 to 2.1 µm in diameter. The edges of the gap junction are outlined by the cellular membranes of endothelial cells. The endothelial cytoplasm contains abundant free ribosomes and mitochondria. × 15,750.

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    Electron micrograph showing a deformed erythrocyte located within the vascular wall of a macrocapillary, dissecting the space between endothelial cells and a pericyte. Scattered collagen fibers and amorphous material are located outside the vessel. × 2580.

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    Electron micrograph showing an endothelial gap junction widely open, where pseudopod-like extensions of two erythrocytes exist. Two other extravasated erythrocytes can also be seen. The endothelial cytoplasm contains numerous lysosomes and Weibel-Palade bodies. × 7040.

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    Electron micrograph showing several deformed platelets located within or adhering to the vascular wall of a macrocapillary. Most of them are of relatively high density with deformed organelles. Many cytoplasmic processes are extruding from both surfaces of the endothelium. The pericyte has numerous pseudopod-like extensions. × 10,500.

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    Electron micrograph showing a macrocapillary with two endothelial gap junctions in the same section. In the right endothelial gap junction, which is as large as 8 µm in diameter, there is an aggregation of several platelets. The endothelial nucleus adjacent to this gap junction has many infoldings. Erythrocytes are squeezing out of the left endothelial gap junction, which is 0.7 µm in diameter. × 10,500.

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    Electron micrograph of an endothelial gap junction 2 µm in diameter formed between adjacent endothelial cells. The basement membrane overlying the endothelial gap junction is discontinuous. × 9150.

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    Electron micrograph showing two erythrocytes easily deformed enough to squeeze out of the macrocapillary through an endothelial gap junction measuring 0.8 µm in diameter. The gap is outlined by the marginal fold. × 15,000.

References

1.

Cotran RS: The delayed and prolonged vascular leakage in inflammation. II. An electron microscopic study of the vascular response after thermal injury. Am J Pathol 46:5896201965Cotran RS: The delayed and prolonged vascular leakage in inflammation. II. An electron microscopic study of the vascular response after thermal injury. Am J Pathol 46:589–620 1965

2.

Friede RLSchachenmayr W: The origin of subdural neomembranes. II. Fine structure of neomembranes. Am J Pathol 92:69841978Friede RL Schachenmayr W: The origin of subdural neomembranes. II. Fine structure of neomembranes. Am J Pathol 92:69–84 1978

3.

Glover DLabadie EL: Physiopathogenesis of subdural hematomas. Part 2: Inhibition of growth of experimental hematomas with dexamethasone. J Neurosurg 45:3933971976Glover D Labadie EL: Physiopathogenesis of subdural hematomas. Part 2: Inhibition of growth of experimental hematomas with dexamethasone. J Neurosurg 45: 393–397 1976

4.

Ito HYamamoto SKomai Tet al: Role of local hyperfibrinolysis in the etiology of chronic subdural hematoma. J Neurosurg 45:26311976Ito H Yamamoto S Komai T et al: Role of local hyperfibrinolysis in the etiology of chronic subdural hematoma. J Neurosurg 45:26–31 1976

5.

Kawano NSuzuki K: Presence of smooth-muscle cells in the subdural neomembrane. J Neurosurg 54:6466511981Kawano N Suzuki K: Presence of smooth-muscle cells in the subdural neomembrane. J Neurosurg 54:646–651 1981

6.

Labadie ELGlover D: Physiopathogenesis of subdural hematomas. Part 1: Histological and biochemical comparisons of subcutaneous hematoma in rats with subdural hematoma in man. J Neurosurg 45:3823921976Labadie EL Glover D: Physiopathogenesis of subdural hematomas. Part 1: Histological and biochemical comparisons of subcutaneous hematoma in rats with subdural hematoma in man. J Neurosurg 45:382–392 1976

7.

Majno GPalade GE: Studies on inflammation. I. The effect of histamine and serotonin on vascular permeability: an electron microscopic study. J Biophys Biochem Cytol 11:5716051961Majno G Palade GE: Studies on inflammation. I. The effect of histamine and serotonin on vascular permeability: an electron microscopic study. J Biophys Biochem Cytol 11:571–605 1961

8.

Rowley DA: Venous constriction as the cause of increased vascular permeability produced by 5-hydroxytryptamine, histamine, bradykinin and 48/80 in the rat. Br J Exp Pathol 45:56671964Rowley DA: Venous constriction as the cause of increased vascular permeability produced by 5-hydroxytryptamine histamine bradykinin and 48/80 in the rat. Br J Exp Pathol 45:56–67 1964

9.

Sato SSuzuki J: Ultrastructural observations of the capsule of chronic subdural hematoma in various clinical stages. J Neurosurg 43:5695781975Sato S Suzuki J: Ultrastructural observations of the capsule of chronic subdural hematoma in various clinical stages. J Neurosurg 43:569–578 1975

10.

Schoefl GI: Studies on inflammation. III. Growing capillaries: their structure and permeability. Virchows Arch (Pathol Anat) 337:971411963Schoefl GI: Studies on inflammation. III. Growing capillaries: their structure and permeability. Virchows Arch (Pathol Anat) 337:97–141 1963

11.

Watanabe SShimada HIshii S: Production of clinical form of chronic subdural hematoma in experimental animals. J Neurosurg 37:5525611972Watanabe S Shimada H Ishii S: Production of clinical form of chronic subdural hematoma in experimental animals. J Neurosurg 37:552–561 1972

12.

Yamashima TShimoji TKomai Tet al: [Growing mechanism of chronic subdural hematoma — light and electron microscopic study on outer membranes of chronic subdural hematoma.] Neurol Med Chir 18:7437521978 (Jpn)Yamashima T Shimoji T Komai T et al: [Growing mechanism of chronic subdural hematoma — light and electron microscopic study on outer membranes of chronic subdural hematoma.] Neurol Med Chir 18: 743–752 1978 (Jpn)

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