[Banded filamentous associates in the intra- and extracellular space in connection with collagen degradation (author's transl)]

Long-spacing collagen and proteoglycans in pathologic tissues

The presence of proteoglycans in fibrous long-spacing collagen (FLSC) was assessed in various pathologic tissues using the highly selective proteoglycan stains cuprolinic blue and polyethyleneimine. Two types of FLSC could be distinguished: one that contained proteoglycans and one that did not. The conditions in which these types occurred suggested a completely different physiologic significance. Also, their morphologies were different: The FLSC containing proteoglycans constituted compact, often fusiform structures long known in diagnostic electron microscopy as Luse bodies. In accordance with the literature, this compact type of FLSC was found especially in schwannomas and other neurogenic tumors. Enzymatic digestion experiments indicated that the proteoglycan present was dermatan sulfate proteoglycan. The average periodicities measured ranged from 101 to 147 nm. The type of FLSC lacking proteoglycans, on the other hand, formed dispersed aggregates. This dispersed FLSC had periodicities ranging from 79 to 103 nm (ie, just below those of the compact type). It was found only under circumstances in which there was high collagen breakdown and/or turnover. That dispersed FLSC is a marker for collagen degradation was further supported by its presence inside fibroblasts engaged in collagen phagocytosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Intractable vasculitis, resorptive osteolysis, and immunity to type I collagen in type VIII Ehlers-Danlos syndrome

A unique patient with type VIII Ehlers-Danlos syndrome and cutaneous vasculitis, resorptive osteolysis, and cardiac valvular disease is described. Collagen analyses identified morphologic and physical abnormalities of type I collagen. The patient's T lymphocytes could be propagated in vitro with type I collagen and produced a 60-kd lymphokine that bound this protein. Cellular autoimmunity to type I collagen may be responsible for this patient's intractable clinical condition.

An immunohistochemical study of human endometrial extracellular matrix during the menstrual cycle and first trimester of pregnancy

Changes in the organisation and composition of extracellular matrix in human endometrium during the menstrual cycle and early pregnancy have been assessed by immunofluorescence. Amongst interstitial components, type-III and type V-collagens and fibronectin are present in endometrial stroma throughout the menstrual cycle as well as in first trimester decidua. Type V-collagen epitopes are masked early in the cycle, but become accessible in first trimester decidua. Type VI-collagen is abundant in endometrium in the proliferative phase, but is progressively lost in the secretory phase and decidua, in which it is retained only in blood vessel walls. Vitronectin is present in some blood vessels in decidua. Decidualising stromal cells also produce basement membrane components (type IV-collagen, laminin, heparan sulphate proteoglycan and a glycoprotein family recognised by monoclonal antibody G71) and these become organised into a pericellular aura.

Ultrastructural evidence of collagenolytic activity in ductal infiltrating carcinoma of the human breast

The stroma of ductal infiltrating carcinoma of the human breast shows characteristic and localized areas of collagen rarefaction and fragmentation. This finding has been correlated with a peculiar type of fibrillar damage, observed in a small percentage of collagen fibrils isolated in the native state from the tumour stroma. The same pattern of lesion has been reproduced in vitro by human collagenase digestion on reconstituted fibrils. No effect has been detected by other nonspecific proteases in the same system.

Type VI collagen in extracellular, 100-nm periodic filaments and fibrils: identification by immunoelectron microscopy

Filaments and fibrils that exhibit a 100-nm axial periodicity and occur in the medium and in the deposited extracellular matrix of chicken embryo and human fibroblast cultures have been tentatively identified with type VI collagen on the basis of their similar structural characteristics (Bruns, R. R., 1984, J. Ultrastruct. Res., 89:136-145). Using indirect immunoelectron microscopy and specific monoclonal and polyclonal antibodies, we now report their positive identification with collagen VI and their distribution in fibroblast cultures and in tendon. Primary human foreskin fibroblast cultures, labeled with anti-type VI antibody and studied by fluorescence microscopy, showed a progressive increase in labeling and changes in distribution with time up to 8 d in culture. With immunoelectron microscopy and monoclonal antibodies to human type VI collagen followed by goat anti-mouse IgG coupled to colloidal gold, they showed in thin sections specific 100-nm periodic labeling on extracellular filaments and fibrils: one monoclonal antibody (3C4) attached to the band region and another (4B10) to the interband region of the filaments and fibrils. Rabbit antiserum to type VI collagen also localized on the band region, but the staining was less well defined. Control experiments with antibodies to fibronectin and to procollagen types I and III labeled other filaments and fibrils, but not those with a 100-nm period. Heavy metal-stained fibrils with the same periodic and structural characteristics also have been found in both adult rat tail tendon and embryonic chicken tendon subjected to prolonged incubation in culture medium or treatment with adenosine 5'-triphosphate at pH 4.6. We conclude that the 100-nm periodic filaments and fibrils represent the native aggregate form of type VI collagen. It is likely that banded fibrils of the same periodicity and appearance, reported by many observers over the years in a wide range of normal and pathological tissues, are at least in part, type VI collagen.

Filamentous aggregates of collagen. Ultrastructural evidence for collagen-fibril degradation in situ

Filamentous aggregates of collagen are distinct structures in the pathological dermis. These aggregates are distinguishable from fibrous long-spacing collagen (in vitro and at biopsy) and the Luse body. The aggregates are produced from dermal collagen fibrils by clostridial collagenase and culture-medium extract, which supposedly contains cellular collagenase at a neutral pH, as well as by organ cultures. In vitro experiments showed that carrageenan granuloma contains fibrous long-spacing collagen and segment long-spacing collagen. The granuloma also contains the aggregates. The aggregates were found in skin biopsies from syphilitic chancres, acrosclerotic scleroderma, morphea, mycosis fungoides, myeloid leukemia, mastocytosis and malignant melanoma. These findings indicate that the aggregates are products of the in situ degradation of collagen fibrils by some collagenolytic factor. This factor may originate in fibroblast-like cells, reticulum cells, leukemia cells, mast cells and melanoma cells.

Beaded filaments and long-spacing fibrils: relation to type VI collagen

"Beaded filaments" have been found in fibroblast cultures prepared from chicken embryo leg tendons and cornea and from the dermis of human skin. With negative staining, they appear as single, unbranched, flexible strands approximately 3 nm in width and up to at least 2 microns in length. Pairs of "beads" are distributed on the filament at regular intervals of 110 nm. The beaded filaments appear to be resistant to the action of trypsin and bacterial collagenase. The filaments also occur in bundles with beads laterally aligned to form long-spacing-type fibrils, which appear to be identical with many fibrous-long-spacing-type fibrils described, but not identified, by others in a variety of normal and pathological tissues. The long-spacing fibrils are numerous at several sites of active collagen fibrillogenesis. Comparison of the beaded filament structure with molecular models for various collagens described in the literature suggests that they are a filamentous form of type VI collagen.

Thallium chondrodystrophy in chick embryos: ultrastructural changes in the epiphyseal plate

Using the transmission electron microscope, we sought to describe the morphology of thallium sulfate-induced chondrodystrophy in chick embryos. There was cell death and degeneration in all zones of growth cartilage, but the cells and matrix of the hypertrophic zone were the most severely affected. Ultrastructural changes of the hypertrophic chondrocytes consisted of alteration of the cytoplasmic contents and of the intercellular matrix; the cell membrane was smooth and without cytoplasmic extensions. The cytoplasm was filled with dilated rough endoplasmic reticulum, vacuoles of varying sizes and contents, and lipidlike bodies with electron-dense granules; mineral crystals, collagen, and degenerating mitochondria were present. The matrix showed only spotty calcification and a reduced number of dense bodies, vesicles, and granules. The cells appeared to have failed to exteriorize cell products across the plasmalemma. Failure to exteriorize cell products and to form cytoplasmic processes reduced the number of potential nucleation sites for calcification. The ultrastructure of osteocytes was much less affected.

Relapsing polychondritis. An ultrastructural study of elastic and collagen fibres degradation revealed by tannic acid

In a case of relapsing polychondritis, ultrastructural study of ear cartilage using tannic acid staining showed patterns of degradation of elastic and collagen fibres. The participation of macrophages and chondrocytes in the resorption of ear cartilage is discussed.

Multiple cutaneous fibromyxomas: a light and electron microscopic study

A 27-year-old woman developed many nodular lesions, ranging in diameter from 3 mm to 15 mm and clinically indistinguishable from dermatofibromas. Light microscopic examination showed large amounts of mucin, fibroblasts and histiocytes throughout the dermis. Electron microscopic study revealed wide electron lucent areas and long branching winding electron dense threads occupying the ground substance. While dilated cisternae of endoplasmic reticulum containing a finely granular material characterized the fibroblasts, banded structures, intracellular collagen and myelinoid figures were prominent in the histiocytes. The term fibromyxoma is introduced to designate this tumor.