Developing Elastic Fibers in the Chick Embryo

1968 ◽  
Vol 26 ◽  
pp. 58-59
Author(s):  
C. R. Basom
Keyword(s):  
Electron Microscopy ◽  
Elastic Fiber ◽  
Fiber Formation ◽  
Collagen Fibrils ◽  
Ground Substance ◽  
Elastic Fibers ◽  
The Third ◽  
Immersion Medium ◽  
Individual Unit ◽  
Homogeneous Matrix

The tunica media of the developing chick aorta was examined for elastic fiber formation. Embryos of three to eighteen days incubation age were prepared for electron microscopy by Karnovsky's fixation. Small embryos were fixed by “in toto” immersion: medium sized embryos were previously transected. The aortae of larger embryos were removed prior to fixation. Epon 812 was used for embedment.Irregular masses of amorphous ground substance appeared in the interstitial space of the aortae in three to five day embryos. These masses were located where elastic fibers would later form (Fig. 1). Later loose tangles of microfibrils appeared within the same masses (Fig. 2). In still older embryos, individual unit collagen fibrils appeared within this loose network. At one week's incubation, small elastic fibers could be identified by their homogeneous matrix. These arose within the conglomerate masses described above. At the beginning of the third week compact bundles of colinear unit collagen fibrils appeared (Fig. 3). These fibrils swelled, gradually lost their periodicity and became very lucid (Fig. 4).

scholarly journals Clinical Relevance of Elastin in the Structure and Function of Skin

2021 ◽  
Author(s):  
Leslie Baumann ◽  
Eric F Bernstein ◽  
Anthony S Weiss ◽  
Damien Bates ◽  
Shannon Humphrey ◽  
...  
Keyword(s):  
Wound Healing ◽  
Clinical Relevance ◽  
Structural Integrity ◽  
Elastic Fiber ◽  
Subcutaneous Fat ◽  
Structure And Function ◽  
Fiber Formation ◽  
Elastic Fibers ◽  
Superficial Dermis ◽  
And Function

Abstract Elastin is the main component of elastic fibers, which provide stretch, recoil, and elasticity to the skin. Normal levels of elastic fiber production, organization, and integration with other cutaneous extracellular matrix proteins, proteoglycans, and glycosaminoglycans are integral to maintaining healthy skin structure, function, and youthful appearance. Although elastin has very low turnover, its production decreases after individuals reach maturity and it is susceptible to damage from many factors. With advancing age and exposure to environmental insults, elastic fibers degrade. This degradation contributes to the loss of the skin’s structural integrity; combined with subcutaneous fat loss, this results in looser, sagging skin, causing undesirable changes in appearance. The most dramatic changes occur in chronically sun-exposed skin, which displays sharply altered amounts and arrangements of cutaneous elastic fibers, decreased fine elastic fibers in the superficial dermis connecting to the epidermis, and replacement of the normal collagen-rich superficial dermis with abnormal clumps of solar elastosis material. Disruption of elastic fiber networks also leads to undesirable characteristics in wound healing, and the worsening structure and appearance of scars and stretch marks. Identifying ways to replenish elastin and elastic fibers should improve the skin’s appearance, texture, resiliency, and wound-healing capabilities. However, few therapies are capable of repairing elastic fibers or substantially reorganizing the elastin/microfibril network. This review describes the clinical relevance of elastin in the context of the structure and function of healthy and aging skin, wound healing, and scars and introduces new approaches being developed to target elastin production and elastic fiber formation.

Characterization of Cardiac Function and Arterial Mechanics During Early Postnatal Development in Fibulin-5 Null Mice

2013 ◽  
Author(s):  
Victoria Le ◽  
Hiromi Yanagisawa ◽  
Jessica Wagenseil
Keyword(s):  
Matrix Protein ◽  
Elastic Fiber ◽  
Connective Tissue Disorder ◽  
Fiber Formation ◽  
Extracellular Matrix Protein ◽  
Elastic Fibers ◽  
Arterial Mechanics ◽  
Early Postnatal Development ◽  
Complex Process

Fibulin-5 is an extracellular matrix protein that interacts with other proteins during a complex process that results in elastic fiber formation from the elastin precursor, tropoelastin [1]. Elastic fibers are an important component of tissues requiring elasticity, including large arteries, lungs and skin. In mice lacking fibulin-5 ( Fbln5−/−), these tissues contain disorganized elastic fibers and exhibit decreased elasticity [2]. The phenotype of Fbln5−/− mice is similar to that of humans with cutis laxa, a connective tissue disorder characterized by loose skin and narrow arteries with reduced compliance.

Recent updates on the molecular network of elastic fiber formation

2019 ◽  
Vol 63 (3) ◽  
pp. 365-376 ◽  
Author(s):  
Seung Jae Shin ◽  
Hiromi Yanagisawa
Keyword(s):  
Elastic Fiber ◽  
Building Blocks ◽  
Fiber Formation ◽  
Elastic Fibers ◽  
Fiber Network ◽  
Associated Proteins ◽  
Fibrillin 1 ◽  
A Cell ◽  
Self Aggregation

Abstract Elastic fibers confer elasticity and recoiling to tissues and organs and play an essential role in induction of biochemical responses in a cell against mechanical forces derived from the microenvironment. The core component of elastic fibers is elastin (ELN), which is secreted as the monomer tropoelastin from elastogenic cells, and undergoes self-aggregation, cross-linking and deposition on to microfibrils, and assemble into insoluble ELN polymers. For elastic fibers to form, a microfibril scaffold (primarily formed by fibrillin-1 (FBN1)) is required. Numerous elastic fiber-associated proteins are involved in each step of elastogenesis and they instruct and/or facilitate the elastogenesis processes. In this review, we designated five proteins as key molecules in elastic fiber formation, including ELN, FBN1, fibulin-4 (FBLN4), fibulin-5 (FBLN5), and latent TGFβ-binding protein-4 (LTBP4). ELN and FBN1 serve as building blocks for elastic fibers. FBLN5, FBLN4 and LTBP4 have been demonstrated to play crucial roles in elastogenesis through knockout studies in mice. Using these molecules as a platform and expanding the elastic fiber network through the generation of an interactome map, we provide a concise review of elastogenesis with a recent update as well as discuss various biological functions of elastic fiber-associated proteins beyond elastogenesis in vivo.

Extracellular Connective Tissue Fibrils: A Single Line of Descent

1968 ◽  
Vol 26 ◽  
pp. 52-53
Author(s):  
F. N. Low
Keyword(s):  
Connective Tissue ◽  
Close Association ◽  
Collagen Fibrils ◽  
Elastic Fibers ◽  
Chick Embryos ◽  
Basal Surface ◽  
The Third ◽  
Tissue Space ◽  
Dorsal Ectoderm ◽  
Boundary Membrane

The fine structure of developing extracellular connective tissue fibrils, is demonstrable in normal chick embryos. Before incubation begins primary fibrils are present in the intermittent boundary membrane (basement membrane, basal lamina) of the basal surface of the epiblast. These give rise to microfibrils which first become free in the tissue space at about 24 hours incubation (Fig. 1). The first noticeable locus of microfibrillar concentration appears between the head process (early notochord) and the dorsal ectoderm. By 40 to 45 hours a heavy tangle of microfibrils occupies the acellular area surrounding the notochord and remains conspicuous during the third day (Fig. 2). At 60 to 72 hours microfibrils begin to appear in close association with free mesenchymal cells (Fig. 3). Periodicity slowly develops in the larger microfibrils and the resultant unit collagen fibrils will aggregate to form the reticular and collagen fibers of light microscopy. During the second and third weeks of incubation microfibrils and unit collagen fibrils contribute to the formation of elastic fibers.

scholarly journals IUGR decreases elastin mRNA expression in the developing rat lung and alters elastin content and lung compliance in the mature rat lung

2011 ◽  
Vol 43 (9) ◽  
pp. 499-505 ◽  
Author(s):  
Lisa A. Joss-Moore ◽  
Yan Wang ◽  
Xing Yu ◽  
Michael S. Campbell ◽  
Christopher W. Callaway ◽  
...  
Keyword(s):  
Elastic Fiber ◽  
Lung Compliance ◽  
Fiber Formation ◽  
Elastic Fibers ◽  
Mrna Levels ◽  
Rat Lung ◽  
Mrna Transcript ◽  
Transcript Levels ◽  
Alveolar Development ◽  
Fiber Deposition

Complications of intrauterine growth restriction (IUGR) include increased pulmonary morbidities and impaired alveolar development. Normal alveolar development depends upon elastin expression and processing, as well as the formation and deposition of elastic fibers. This is true of the human and rat. In this study, we hypothesized that uteroplacental insufficiency (UPI)-induced IUGR decreases mRNA levels of elastin and genes required for elastin fiber synthesis and assembly, at birth (prealveolarization) and postnatal day 7 (midalveolarization) in the rat. We further hypothesized that this would be accompanied by reduced elastic fiber deposition and increased static compliance at postnatal day 21 (mature lung). We used a well characterized rat model of IUGR to test these hypotheses. IUGR decreases mRNA transcript levels of genes essential for elastic fiber formation, including elastin, at birth and day 7. In the day 21 lung, IUGR decreases elastic fiber deposition and increases static lung compliance. We conclude that IUGR decreases mRNA transcript levels of elastic fiber synthesis genes, before and during alveolarization leading to a reduced elastic fiber density and increased static lung compliance in the mature lung. We speculate that the mechanism by which IUGR predisposes to pulmonary disease may be via decreased lung elastic fiber deposition.

scholarly journals The Development in vitro and in vivo of Fusion of the Palatal Processes of Rat Embryos

Development ◽  
1963 ◽  
Vol 11 (3) ◽  
pp. 605-619
Author(s):  
Thomas M. Moriarty ◽  
Sam Weinstein ◽  
R. D. Gibson
Keyword(s):  
Cleft Palate ◽  
Elastic Fiber ◽  
Critical Time ◽  
Mouse Embryos ◽  
Laboratory Animals ◽  
Growth Spurt ◽  
Ground Substance ◽  
Elastic Fibers

The congenital anomaly of cleft palate can now be reproduced by a variety of teratogenetic agents in a number of laboratory animals (Kalter & Warkany, 1959). Through the use of the induced cleft palate numerous studies have been directed toward detecting the developmental mishaps which create this defect. The work of Fraser et al. (1957) suggested that various positional factors of the developing palatal and facial structures may be the underlying cause for failure of palatal closure in mouse embryos. Walker & Fraser (1956) observed elastic fibers among the palatal processes of mouse embryos which they suggested might impart a ‘shelf force’ necessary for proper closure and fusion. However, Walker (1961) has since reported that there is a mucopolysaccharide in the ground substance of the palatal mesenchyme rather than an elastic fiber network. Asling et al. (1960) noted a growth spurt of the developing mandible during the critical time of palatal process closure.

scholarly journals Fibulin-2 Is Dispensable for Mouse Development and Elastic Fiber Formation

2007 ◽  
Vol 28 (3) ◽  
pp. 1061-1067 ◽  
Author(s):  
Francois-Xavier Sicot ◽  
Takeshi Tsuda ◽  
Dessislava Markova ◽  
John F. Klement ◽  
Machiko Arita ◽  
...  
Keyword(s):  
Matrix Protein ◽  
Elastic Fiber ◽  
Embryonic Stem ◽  
Fiber Formation ◽  
Extracellular Matrix Protein ◽  
Elastic Fibers ◽  
Mouse Development ◽  
Fibrillin 1

ABSTRACT Fibulin-2 is an extracellular matrix protein belonging to the five-member fibulin family, of which two members have been shown to play essential roles in elastic fiber formation during development. Fibulin-2 interacts with two major constituents of elastic fibers, tropoelastin and fibrillin-1, in vitro and localizes to elastic fibers in many tissues in vivo. The protein is prominently expressed during morphogenesis of the heart and aortic arch vessels and at early stages of cartilage development. To examine its role in vivo, we generated mice that do not express the fibulin-2 gene (Fbln2) through homologous recombination of embryonic stem cells. Unexpectedly, the fibulin-2-null mice were viable and fertile and did not display gross and anatomical abnormalities. Histological and ultrastructural analyses revealed that elastic fibers assembled normally in the absence of fibulin-2. No compensatory up-regulation of mRNAs for other fibulin members was detected in the aorta and skin tissue. However, in the fibulin-2 null aortae, fibulin-1 immunostaining was increased in the inner elastic lamina, where fibulin-2 preferentially localizes. The results demonstrate that fibulin-2 is not required for mouse development and elastic fiber formation and suggest possible functional redundancy between fibulin-1 and fibulin-2.

scholarly journals Developmental Expression of Latent Transforming Growth Factor β Binding Protein 2 and Its Requirement Early in Mouse Development

2000 ◽  
Vol 20 (13) ◽  
pp. 4879-4887 ◽  
Author(s):  
J. Michael Shipley ◽  
Robert P. Mecham ◽  
Erika Maus ◽  
Jeffrey Bonadio ◽  
Joel Rosenbloom ◽  
...  
Keyword(s):  
In Situ Hybridization ◽  
Growth Factor ◽  
Transforming Growth Factor ◽  
Binding Protein ◽  
Elastic Fiber ◽  
Transforming Growth Factor Β ◽  
Fiber Formation ◽  
Developmental Expression ◽  
Elastic Fibers

ABSTRACT Latent transforming growth factor β (TGF-β) binding protein 2 (LTBP-2) is an integral component of elastin-containing microfibrils. We studied the expression of LTBP-2 in the developing mouse and rat by in situ hybridization, using tropoelastin expression as a marker of tissues participating in elastic fiber formation. LTBP-2 colocalized with tropoelastin within the perichondrium, lung, dermis, large arterial vessels, epicardium, pericardium, and heart valves at various stages of rodent embryonic development. Both LTBP-2 and tropoelastin expression were seen throughout the lung parenchyma and within the cortex of the spleen in the young adult mouse. In the testes, LTBP-2 expression was seen within lumenal cells of the epididymis in the absence of tropoelastin. Collectively, these results imply that LTBP-2 plays a structural role within elastic fibers in most cases. To investigate its importance in development, mice with a targeted disruption of the Ltbp2 gene were generated.Ltbp2 −/− mice die between embryonic day 3.5 (E3.5) and E6.5. LTBP-2 expression was not detected by in situ hybridization in E6.5 embryos but was detected in E3.5 blastocysts by reverse transcription-PCR. These results are not consistent with the phenotypes of TGF-β knockout mice or mice with knockouts of other elastic fiber proteins, implying that LTBP-2 performs a yet undiscovered function in early development, perhaps in implantation.

scholarly journals Elastic Laminar Reorganization Occurs with Outward Diameter Expansion during Collateral Artery Growth and Requires Lysyl Oxidase for Stabilization

2021 ◽  
Author(s):  
Ryan M McEnaney ◽  
Dylan D McCreary ◽  
Nolan Skirtich ◽  
Elizabeth Andraska ◽  
Ulka Sachdev ◽  
...  
Keyword(s):  
Structural Changes ◽  
Lysyl Oxidase ◽  
Elastic Fiber ◽  
Multiphoton Microscopy ◽  
Fiber Formation ◽  
Elastic Fibers ◽  
Large Artery ◽  
Luminal Diameter ◽  
Collateral Arteries ◽  
Collateral Artery

When a large artery becomes occluded, hemodynamic changes stimulate remodeling of arterial networks to form collateral arteries in a process termed arteriogenesis. However, the structural changes necessary for collateral remodeling have not been defined. We hypothesize that decon-struction of the extracellular matrix is essential to the remodeling of smaller arteries into effective collaterals. Using multiphoton microscopy, we analyzed collagen and elastin structure in maturing collateral arteries isolated from ischemic rat hindlimbs. Collateral arteries harvested at different timepoints showed progressive diameter expansion associated with striking rearrangement of in-ternal elastic lamina (IEL) into a loose fibrous mesh, a pattern persisting at 8 weeks. Despite a 2.5-fold increase in luminal diameter, total elastin content remained unchanged in collaterals compared with control arteries. Among the collateral midzones, baseline elastic fiber content is low. Outward remodeling of these vessels with a 10-20 fold diameter increase was associated with fractures of the elastic fibers and evidence of increased wall tension as demonstrated by straight-ening of the adventitial collagen. Inhibition of lysyl oxidase (LOX) function with β-aminopropionitrile resulted in severe fragmentation or complete loss of continuity of the IEL in developing collaterals. Collateral artery development is associated with permanent redistribution of existing elastic fibers to accommodate diameter growth. We found no evidence of new elastic fiber formation. Stabilization of the arterial wall during outward remodeling is necessary and dependent on LOX activity.

scholarly journals Neuraminidase-1 is required for the normal assembly of elastic fibers

2008 ◽  
Vol 295 (4) ◽  
pp. L637-L647 ◽  
Author(s):  
Barry Starcher ◽  
Alessandra d'Azzo ◽  
Patrick W. Keller ◽  
Gottipati K. Rao ◽  
Deepa Nadarajah ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Smooth Muscle ◽  
Random Distribution ◽  
Elastic Fiber ◽  
Abnormal Development ◽  
Elastic Fibers ◽  
Tight Skin ◽  
Fibrillin 1 ◽  
Histopathological Effects

The assembly of elastic fibers in tissues that undergo repeated cycles of extension and recoil, such as the lungs and blood vessels, is dependent on the proper interaction and alignment of tropoelastin with a microfibrillar scaffold. Here, we describe in vivo histopathological effects of neuraminidase-1 (Neu1) deficiency on elastin assembly in the lungs and aorta of mice. These mice exhibited a tight-skin phenotype very similar to the Tsk mouse. Normal septation of Neu1-null mice did not occur in neonatal mice, resulting in enlarged alveoli that were maintained in adults. The abnormal development of elastic fibers was remarkable under electron microscopy and confirmed by the overlapping distribution of elastin, fibrillin-1, fibrillin-2, and fibulin-5 (Fib-5) by the light microscopy immunostainings. Fib-5 fibers appeared diffuse and unorganized around the alveolar walls and the apex of developing secondary septal crests. Fibrillin-2 deposition was also abnormal in neonatal and adult lungs. Dispersion of myofibroblasts appeared abnormal in developing lungs of Neu1-null mice, with a random distribution of myofibroblast around the alveolar walls, rather than concentrating at sites of elastin synthesis. The elastic lamellae in the aorta of the Neu1-null mice were thinner and separated by hypertrophic smooth muscle cells that were surrounded by an excess of the sialic acid-containing moieties. The concentration of elastin, as measure by desmosine levels, was significantly reduced in the aorta of Neu1-null mice. Message levels for tropoelastin and Fib-5 were normal, suggesting the elastic fiber defects in Neu1-null mice result from impaired extracellular assembly.

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