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Collagen Fibril Diameters (collagen + fibril_diameter)

Distribution by Scientific Domains

Medical Sciences	80%

Selected Abstracts

Collagen types I, III, and V constitute the thick collagen fibrils of the mouse decidua

MICROSCOPY RESEARCH AND TECHNIQUE, Issue 1 2007
Karin Spiess
Abstract A mammal's endometrium is deeply remodeled while receiving and implanting an embryo. In addition to cell proliferation and growth, endometrial remodeling also comprises synthesis and degradation of several molecular components of the extracellular matrix. All of these events are orchestrated by a precise sequence of ovarian hormones and influenced by several types of cytokines. As we have previously reported, an intriguing and rapid increase in collagen fibril diameter occurs in the decidualized areas of the endometrium, surrounding the implantation crypt, whereas collagen fibrils situated far from the embryo remain unchanged. Collagen fibrilogenesis is a complex molecular process coordinated by a number of factors, such as the types and amounts of glycosaminoglycans and proteoglycans associated with collagen molecules. Collagen genetic type, mechanical stress, aging, and other factors not yet identified also contribute to this development. A recent study suggests that thick fibrils from mouse decidua are formed, at least in part, by aggregation of thin fibrils existing in the stroma before the onset of decidualization. In the present ultrastructural study using single and double immunogold localization, we showed that both thin and thick collagen fibrils present in the mouse pregnant endometrium endometrium are heterotypic structures formed at least by type I, type III, and type V collagens. However, type V collagen predominates in the thick collagen fibrils, whereas it is almost absent of the thin collagen fibrils. The putative role of type V homotrimer in the rapid increase of the diameter of collagen fibrils of the mouse decidua is discussed. Microsc. Res. Tech., 2006. © 2006 Wiley-Liss, Inc. [source]

Ultrastructural changes induced in cutaneous collagen by ultraviolet-A1 and psoralen plus ultraviolet A therapy in systemic sclerosis

THE JOURNAL OF DERMATOLOGY, Issue 2 2008
Noriyuki SAKAKIBARA
ABSTRACT In the present study, we examined the ultrastructural alterations in collagen fibrils clinically softened by ultraviolet-A1 (UVA1, 340,400 nm) therapy and psoralen plus long-wave ultraviolet (PUVA) therapy and compared collagen fibril diameters in four patients with systemic sclerosis (SSc). In skin sclerosis, the dermis is compacted from the epidermal layer to the sweat glands, and the collagen bundles are thicker with decreased space between them. We obtained skin specimens before and after UVA1 or PUVA therapy, and compared cutaneous alterations in one diffuse-type patient and one limited-type patient following UVA1 therapy, and in two diffuse-type patients following PUVA treatment. Ultramicroscopic analysis revealed that UVA1 treatment decreased the diameter of the broad collagen fibrils, mainly in the upper reticular layer. PUVA induced similar alterations in the collagen fibrils, extending to the upper and middle reticular layers. PUVA therapy induced alterations in collagen fibril diameter in deeper layers than did UVA1 therapy, which might be related to the direct action of UV light and the depth of the light penetration. In three of four patients, collagen fibril diameter decreased, collagen fibril thickness equalized, and new, thin fibrils developed among the collagen fibrils, suggesting that collagen degradation and synthesis underlie the alterations induced by UVA1 and PUVA phototherapies. [source]

Long-term effects of porcine small intestine submucosa on the healing of medial collateral ligament: A functional tissue engineering study

JOURNAL OF ORTHOPAEDIC RESEARCH, Issue 4 2006
Rui Liang
Abstract Porcine small intestinal submucosa (SIS) was previously shown to enhance the mechanical properties of healing medial collateral ligaments (MCL), and the histomorphological appearance and collagen type V/I ratio were found to be close to those of normal MCL. We hypothesized that at a longer term, 26 weeks, SIS could guide a better organized neo-ligament formation, increasing mechanical properties and increasing collagen fibril diameters mediated by a reduction in collagen type V. A 6 mm gap injury in the right MCL was surgically created in 38 rabbits, while the contralateral intact MCL served as a sham-operated control. In half the animals, a strip of SIS was sutured onto the severed ends. In the other half, no SIS was applied. The cross-sectional area (CSA) was determined with a laser micrometer system. The femur,MCL,tibia complex was mechanically tested in uniaxial tension. Histomorphology was determined through H&E and immunofluorescent staining and transmission electron microscopy (TEM). Sodium-dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) was used to determine collagen type V/I ratio. SIS-treated MCLs displayed a 28% reduction in CSA, a 33% increase in tangent modulus, and a 50% increase in tensile strength compared with the nontreated group (p,<,0.05). TEM showed groups of collagen fibrils with larger diameters in the SIS-treated ligaments in comparison with uniformly small fibrils for the nontreated group. H&E staining showed more densely stained collagen fibers in the SIS-treated group aligned along the longitudinal axis with more interspersed spindle-shaped cells. Immunofluorescent staining showed less collagen type V signals, confirmed by a 5% lower ratio of collagen type V/I compared with the nontreated controls (p,<,0.05). The findings extend the shorter term 12-week results, and support the potential of porcine SIS as a bioscaffold to enhance ligament healing. © 2006 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res [source]

Ultrastructural changes induced in cutaneous collagen by ultraviolet-A1 and psoralen plus ultraviolet A therapy in systemic sclerosis

Combined role of type IX collagen and cartilage oligomeric matrix protein in cartilage matrix assembly: Cartilage oligomeric matrix protein counteracts type IX collagen,induced limitation of cartilage collagen fibril growth in mouse chondrocyte cultures

ARTHRITIS & RHEUMATISM, Issue 12 2009
K. Blumbach
Objective Defects in the assembly and composition of cartilage extracellular matrix are likely to result in impaired matrix integrity and increased susceptibility to cartilage degeneration. The aim of this study was to determine the functional interaction of the collagen fibril,associated proteins type IX collagen and cartilage oligomeric matrix protein (COMP) during cartilage matrix formation. Methods Primary chondrocytes from mice deficient in type IX collagen and COMP (double-deficient) were cultured in monolayer or alginate beads. Anchorage of matrix proteins, proteoglycan and collagen content, collagen crosslinks, matrix metalloproteinase activity, and mechanical properties of the matrix were measured. Electron microscopy was used to study the formation of fibrillar structures. Results In cartilage lacking both type IX collagen and COMP, matrilin 3 showed decreased matrix anchorage. Less matrilin 3 was deposited in the matrix of double-deficient chondrocytes, while larger amounts were secreted into the medium. Proteoglycans were less well retained in the matrix formed in alginate cultures, while collagen deposition was not significantly affected. Electron microscopy revealed similar cartilage collagen fibril diameters in the cultures of double-deficient and wild-type chondrocytes. In contrast, a larger fibril diameter was observed in the matrix of chondrocytes deficient in only type IX collagen. Conclusion Our results show that type IX collagen and COMP are involved in matrix assembly by mediating the anchorage and regulating the distribution of other matrix macromolecules such as proteoglycans and matrilins and have counteracting effects on collagen fibril growth. Loss of type IX collagen and COMP leads to matrix aberrations that may make cartilage more susceptible to degeneration. [source]