Mircofibrils in the Aorta

Krauhs, Jane M.

doi:10.3109/03008208309004851

Cited by 19 publications

(8 citation statements)

References 33 publications

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“…The only structures devoid of proteoglycans were the cell‐associated fibronectin‐positive layers, the elastin‐associated material, and the oxytalan fibers. The latter observation is in contrast to the finding of proteoglycans in oxytalan fibers (or on microfibrils) by several investigators (Goldfischer et al, 1983; Krauhs, 1983). The reason for this discrepancy may be the superiority of cuprolinic blue and polyethyleneimine used by us over the ruthenium red used by these authors (Scott, 1980).…”

Section: Discussioncontrasting

confidence: 80%

Extracellular matrix of the human aortic media: An ultrastructural histochemical and immunohistochemical study of the adult aortic media

et al. 2000

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Aortic distensability is the key to normal aortic function and relates to the lamellar unit in the media. However, the organization of the extracellular matrix components in these lamellar units, which are largely responsible for the distensability, is insufficiently known, especially in the human. We therefore performed a detailed ultrastructural analysis of these components. Thoracic aortas of 56 individuals (age 45-74 years), none of whom suffered from aortic disease, were studied by immunoelectron microscopy of elastin, collagen types I, III, IV, V, and VI, fibronectin, and fibrillin-1, and by ultrastructural histochemistry of proteoglycans, which were further characterized by enzymatic digestion. The elastic lamellae were closely associated with thick collagen fibers containing types I, III, and V collagen. Between these collagen fibers, numerous complex, circumferentially oriented streaks of elastin protruded from the lamellae. In contrast to what is usually reported in the aortas of experimental animals, the smooth muscle cells preferentially adhered to these ill-defined streaks rather than directly to the solid lamellae. Fibrillin-1- and type VI collagen-containing bundles of microfibrils (oxytalan fibers) were also involved in the smooth muscle cell-elastin contact. The smooth muscle cells were invested by basal lamina-like layers connecting them to each other as well as to the oxytalan fibers. Unexpectedly, these layers were abundantly labeled by anti-fibronectin, whereas type IV collagen, a specific basement membrane component, was mainly found in larger, flocculent deposits. The proteoglycans present were collagen-associated dermatan sulfate proteoglycan, cell-associated heparan sulfate proteoglycan, and interstitial chondroitin sulfate proteoglycan. Our observations demonstrate that the extracellular matrix in the human aorta is extremely complex and therefore differs from most descriptions based on experimental animals. They serve as reference for future studies on aortic diseases, such as aneurysmas and dissections.

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Section: Discussioncontrasting

confidence: 80%

Extracellular matrix of the human aortic media: An ultrastructural histochemical and immunohistochemical study of the adult aortic media

et al. 2000

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“…The latter observation is in contrast to the finding of proteoglycans in oxytalan fibers (or on microfibrils) by several investigators (Goldfischer et al, 1983;Krauhs, 1983). The reason for this discrepancy may be the superiority of cuprolinic blue and polyethyleneimine used by us over the ruthenium red used by these authors (Scott, 1980).…”

Section: Identification Of the Proteoglycans; Their Role In The Aorticontrasting

confidence: 54%

“…Also fibronectin was detectable in oxytalan fibers (cf. Krauhs, 1983;Sakai et al, 1986;Mariencheck et al, 1995). Finally, immunoelectron microscopy sometimes revealed traces of elastin in oxytalan fibers, even when no elastin deposits were detectable in conventional specimens (cf.…”

Section: Role Of the Extracellular Matrix Components In The Mechanicamentioning

confidence: 99%

Extracellular matrix of the human aortic media: An ultrastructural histochemical and immunohistochemical study of the adult aortic media

et al. 2000

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Aortic distensability is the key to normal aortic function and relates to the lamellar unit in the media. However, the organization of the extracellular matrix components in these lamellar units, which are largely responsible for the distensability, is insufficiently known, especially in the human. We therefore performed a detailed ultrastructural analysis of these components.Thoracic aortas of 56 individuals (age 45-74 years), none of whom suffered from aortic disease, were studied by immunoelectron microscopy of elastin, collagen types I, III, IV, V, and VI, fibronectin, and fibrillin-1, and by ultrastructural histochemistry of proteoglycans, which were further characterized by enzymatic digestion.The elastic lamellae were closely associated with thick collagen fibers containing types I, III, and V collagen. Between these collagen fibers, numerous complex, circumferentially oriented streaks of elastin protruded from the lamellae. In contrast to what is usually reported in the aortas of experimental animals, the smooth muscle cells preferentially adhered to these ill-defined streaks rather than directly to the solid lamellae. Fibrillin-1-and type VI collagen-containing bundles of microfibrils (oxytalan fibers) were also involved in the smooth muscle cell-elastin contact. The smooth muscle cells were invested by basal lamina-like layers connecting them to each other as well as to the oxytalan fibers. Unexpectedly, these layers were abundantly labeled by anti-fibronectin, whereas type IV collagen, a specific basement membrane component, was mainly found in larger, flocculent deposits. The proteoglycans present were collagen-associated dermatan sulfate proteoglycan, cell-associated heparan sulfate proteoglycan, and interstitial chondroitin sulfate proteoglycan.Our observations demonstrate that the extracellular matrix in the human aorta is extremely complex and therefore differs from most descriptions based on experimental animals. They serve as reference for future studies on aortic diseases, such as aneurysmas and dissections.

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“…The presence of fibronectin within bundles of microfibrils (Krauhs, 1983;Schwarz et al, 1985; Goldfis- Transversely sectioned microfibrils at a magnification lower than in Figure 10, after double immunolabeling for amyloid P with 15 nm and for fibronectin with 5 nm gold particles. a: The large particle indicative of amyloid P is believed to obscure a pentagonal segment from a cross-sectioned microfibril, while the two small particles indicative of fibronectin are associated with a small group of filaments.…”

Section: Discussionmentioning

confidence: 99%

“…Bar = 100 pm; X 225. 3, A third glycoprotein, fibronectin, has been identified by Krauhs (1983)) Schwartz et al (1985), Goldfischer et al (1985), and Streeten and Gibson (1988). The localization of fibronectin on microfibrils is not known, but it has been suggested by Schwartz et al (1985) that it is present at the surface rather than within the core of microfibrils.…”

Section: Introductionmentioning

confidence: 99%

Association of fibronectin with the microfibrils of connective tissue

et al. 1989

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The association of fibronectin with the microfibrils of connective tissue was examined in the zonular fibers of the mouse eye by immunohistochemical methods at the light and electron microscopic level. Mouse eyes fixed in formaldehyde were embedded either in paraffin for immunostaining by the peroxidase-antiperoxidase (PAP) method or in Lowicryl for immunolabeling by antirabbit globulin antibodies bound to 5 or 15 nm gold particles. Ultrastructural studies were also carried out after glutaraldehyde perfusion. Both the PAP and immunogold procedures demonstrated the association of fibronectin with microfibrils. After immunolabeling with 5 nm gold particles, examination at high magnification localized fibronectin to fine filaments that appeared to be attached to the surface of microfibrils. The filaments extended outward singly or formed loose aggregates. Their diameter ranged from 1.2 to 3 nm, with a mean of 1.5 nm. Because of their similarity to the fibronectin molecules previously described after rotary shadowing, the filaments were likely to be fibronectin molecules themselves. Since fibronectin is known to have high affinity for the amyloid P component, a model is presented in which fibronectin filaments are bound to the amyloid P component making up the tubular core of microfibrils in mice. Evidence is presented that fibronectin filaments may link microfibrils to one another and thus insure the continuity and strength of zonular fibers. More generally, it is likely that connective-tissue microfibrils, whether or not inserted into elastic fibers, are bonded through fibronectin to surrounding cells, collagen fibrils, or proteoglycans, and thus insure cohesion among connective tissue elements.

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Mircofibrils in the Aorta

Cited by 19 publications

References 33 publications

Extracellular matrix of the human aortic media: An ultrastructural histochemical and immunohistochemical study of the adult aortic media

Extracellular matrix of the human aortic media: An ultrastructural histochemical and immunohistochemical study of the adult aortic media

Extracellular matrix of the human aortic media: An ultrastructural histochemical and immunohistochemical study of the adult aortic media

Association of fibronectin with the microfibrils of connective tissue

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