Elastic Fibers In Skin Research Articles

The Distribution of Elastic Fibers in the Asian Upper Eyelid Skin

To analyze the distribution and characteristics of upper eyelid skin elastic fibers in different areas of skin thickness and in relation to the eyelid crease. We used 12 postmortem eyelids (6 right, 6 left) of 10 Asian cadavers (mean age: 77.1 years at death), fixed in 10% buffered formalin. Full-thickness sagittal sections of the upper eyelids were dehydrated, embedded in paraffin, and cut in 7-μm-thick sections. The sliced sections were stained with elastica van Gieson. The upper eyelid skin was divided in 2 areas; the thinner and thicker areas. The average distance from the eyelid margin to the border between the 2 areas was 17.8 mm (range, 12.8-24.0 mm). Ten eyelids showed a small amount of elastic fibers in the thinner skin area, and 2 eyelids were rich in elastic fibers in the same area. The volume of elastic fibers multiplied in the thicker skin area. The elastic fibers in the eyelid margin area were fine and nonfragmented, whereas in other areas they were thicker and more fragmented. A part below the skin creases showed the same concentration of elastic fibers to other areas of the upper eyelid skin. Most upper eyelids demonstrated a small amount of elastic fibers in the thinner skin area and a larger amount in the thicker area. The eyelid margin elastic fibers had a normal morphology, whereas in other areas they were more disintegrated, thicker, and fragmented. The eyelid creases and the elastic fiber concentration were unrelated.

Characterizing cutaneous elastic fibers by eosin fluorescence detected by fluorescence microscopy.

Though elastic fibers are as important as collagen fibers in interpretation of the histopathologic findings, it is impossible to observe them on the hematoxylin & eosin (H&E) stained specimen. Characterizing eosin fluorescence emitted by elastic fibers in H&E stained specimens. Normal skin tissue sections were stained in 4 different ways (unstained, hematoxylin only, eosin only, H&E) and observed under a fluorescence microscope using a FITC filter set. Fluorescent findings of 30 H&E-stained specimens showing abnormal dermal findings were compared with bright field findings of Miller's elastic stained specimen. Strong eosin fluorescence was related to the differential binding property of eosin with elastic fibers. Hematoxylin stain quenched excessive eosin fluorescence from other tissue components and contributed to better contrast. Fluorescence microscopy of H&E-stained sections was found to be especially useful in observing mature elastic fibers in the reticular dermis. In 74% of the specimens, eosin fluorescence findings of elastic fibers in reticular dermis matched well with that of specimens with elastic fiber special stain. Analysis of skin elastic fibers by fluorescence microscopy is a useful and complementary method to reveal hidden elastic fibers in H&E-stained specimens.

Observation of the Ultrastructural Organization of Human Dermal Elastic Fibers Using Negative Stain Technique Differences Between Young and Aged Skin Elastic Fibers

Observation of the Ultrastructural Organization of Human Dermal Elastic Fibers Using Negative Stain Technique Differences Between Young and Aged Skin Elastic Fibers

Gla-Rich Protein Is a Novel Vitamin K-Dependent Protein Present in Serum That Accumulates at Sites of Pathological Calcifications

Mineralization of soft tissues is an abnormal process that occurs in any body tissue and can greatly increase morbidity and mortality. Vitamin K-dependent (VKD) proteins play a crucial role in these processes; matrix Gla protein is considered one of the most relevant physiological inhibitors of soft tissue calcification know to date. Several studies have suggested that other, still unknown, VKD proteins might also be involved in soft tissue calcification pathologies. We have recently identified in sturgeon a new VKD protein, Gla-rich protein (GRP), which contains the highest ratio between number of Gla residues and size of the mature protein so far identified. Although mainly expressed in cartilaginous tissues of sturgeon, in rat GRP is present in both cartilage and bone. We now show that GRP is a circulating protein that is also expressed and accumulated in soft tissues of rats and humans, including the skin and vascular system in which, when affected by pathological calcifications, GRP accumulates at high levels at sites of mineral deposition, indicating an association with calcification processes. The high number of Gla residues and consequent mineral binding affinity properties strongly suggest that GRP may directly influence mineral formation, thereby playing a role in processes involving connective tissue mineralization.

Skin elastic fibres: regulation of human elastin promoter activity in transgenic mice.

Elastic fibres form an extracellular network which provides elasticity and resilience to tissues such as the skin. To study the regulation of human elastin gene expression, we have developed a line of transgenic mice which harbour 5.2 kb of human elastin gene promoter region in their genome. This promoter is linked to the chloramphenicol acetyltransferase (CAT) reporter gene which allows determination of the expression of human elastin promoter in different tissues. The highest CAT activity was found in the lungs and aorta, tissues rich in elastin, while lower levels were detected in a variety of other tissues, including skin. Assay of CAT activity in the lungs of fetal and newborn animals revealed high activity which progressively declined during the postnatal period up to six months. Thus, there was evidence of tissue-specific and developmentally regulated expression of the human elastin promoter activity in these mice. These animals were then used to examine the expression of the elastin gene by a variety of factors which have previously shown to alter elastin gene expression, as determined at the mRNA or protein levels. First, injection of transforming growth factor beta 1 (100 ng) subcutaneously into the transgenic animals resulted in a time-dependent elevation of the promoter activity up to 10-fold after a single injection. Secondly, enhancement of the human elastin promoter activity by interleukin 1 beta injected subcutaneously resulted in an approximately 10-fold elevation of the CAT activity. Finally, subcutaneous injection of these animals with triamcinolone acetonide or dexamethasone, two glucocorticosteroids in clinical use, resulted in marked enhancement of human elastin promoter activity. Similar changes were noted in fibroblast cultures established from the transgenic animals. These data indicate that the 5.2 kb upstream segment of the human elastin gene contains cis-elements which allow tissue-specific and developmentally regulated expression of the human elastin promoter. Furthermore, this segment of the gene contains responsive elements to a variety of cytokines and pharmacological agents. Collectively, these data indicate that elastin gene expression in the skin in vivo can be regulated at the transcriptional level.

Pseudoxanthoma elasticum‐like fibers in the inflamed skin of patients without pseudoxanthoma elasticum

Pseudoxanthoma elasticum (PXE) is an inherited disorder leading to characteristic calcified elastic fibers in skin, eyes and vasculature. PXE-like fibers have not been described in inflammatory skin disease in the absence of other signs of PXE. The histopathology of inflamed skin from 13 patients that contained PXE-like fibers but lacked clinical evidence of PXE were studied. Six of these and six comparison specimens from known patients with PXE were subjected to polymerase chain reaction amplification and sequencing of exons 24 and 28 of the PXE-associated gene ABCC6. This genetic analysis employed a novel assay utilizing paraffin-embedded tissue. Incidental PXE-like fibers were found in patients without clinical suspicion of PXE in lesional tissue showing lipodermatosclerosis, granuloma annulare, lichen sclerosus, morphea profunda, erythema nodosum, septal panniculitis, basal cell carcinoma and fibrosing dermatitis. Two patients with PXE-like fibers but without clinical findings of PXE were heterozygous for a PXE-associated ABCC6 sequence alteration. This pilot study shows elastic fibers similar to those of PXE in the lesional skin of patients with a variety of inflammatory skin diseases in the absence of clinical evidence of PXE; and some of these patients harbor changes in ABCC6.

A new pseudopeptidic elastase inhibitor with protective effects on skin elastic fibers following topical administration

A new pseudopeptidic elastase inhibitor with protective effects on skin elastic fibers following topical administration

Pseudoxanthoma elasticum: under-recognized cause of early onset peripheral arterial disease?

A 50-year-old female patient with critical limb ischemia was referred for evaluation and treatment of peripheral arterial disease (PAD). She had a history of stroke in 2002; however, no classical cardiovascular risk factor was detected. Angiography revealed a severe generalized PAD (Panel A). Small, yellowish, flat, soft papules were present in the neck (Panels B and C) and both antecubital fossae. A skin biopsy showed typical calcified elastic fibres (Panel D: part C) and disintegrated and fringed collagen fibrils (Panel D: parts A and B). These findings are consistent with pseudoxanthoma elasticum (synonym: PXE, Gronblad-Strandberg syndrome). It is a systemic inherited disease with a prevalence of 1:25 000‐1:100 000 in white individuals. 1 The defect has been mapped to the ABCC6 gene on chromosome 16 encoding multidrug resistance-associated protein. 2 It causes fragmentation and calcium deposition in elastic fibres of skin, blood vessels, Bruch’s membrane of the eye, and other organs. It is not known how this mutation causes these changes in multiple organs. One hypothesis is chronic oxidative stress. 3 Characteristically, patients suffer from skin lesions, cardiovascular manifestations such as early PAD, myocardial infarction or stroke, and ophthalmologic features (i.e. angioid streaks, peau d’orange and maculopathy). The anticipated prevalence in Germany is at least 1000 patients. However, only a few hundred are diagnosed. Therefore, the disease seems to be under-recognized. Pseudoxanthoma elasticum should be considered as a possible diagnosis in patients with early onset of PAD.

Action of Topical Thyroid Hormone Analogue, Triiodothyroacetic Acid in Reversing Glucocorticoid-Induced Skin Atrophy in Humans

The present study concerns the effect of topical treatment with a cream formulation of triiodothyroacetic acid (TRIAC) in comparison with a placebo preparation in producing a reversal of skin atrophy induced by long-term employment of topical glucocorticoid therapy in humans. A total of 39 patients with clinically verified skin atrophy due to long-term use of topical potent glucocorticoids were randomized. The changes in skin thickness, elastic fibers, and hyaluronic acid were evaluated by means of sonography and histology. After 8 weeks' treatment, the skin thickness measured by sonography increased by 16% in the epidermis, 8% in the dermis, and epidermis + dermis in the placebo group. In the TRIAC 0.1% group, the corresponding values were 24% ( p=0.063) in the epidermis, 28% ( p=0.042) in the dermis, and 25% ( p=0.039) in the epidermis + dermis. After 8 weeks, in the placebo group, the skin thickness measured by biopsy increased by 5% in the epidermis, epidermis + dermis, and 6% in the dermis. In the TRIAC 0.1% group, the corresponding values were 31% ( p=0.041) in the epidermis, 46% ( p=0.041) in the dermis and 44% ( p=0.043) in the epidermis + dermis. After 8 weeks, the elastic fibers of moderately irregular and thickened fibers increased by 56% in the placebo group and 100% ( p=0.043) in the TRIAC 0.1 group. This study indicates that topical treatment with TRIAC appears to reverse glucocorticoid-induced skin atrophy under the narrow conditions tested.

Effect of smoking on skin elastic fibres: morphometric and immunohistochemical analysis

It has been established during recent years that smoking is an independent risk factor for the development of premature facial wrinkling. The underlying mechanism is not well known, but elastic fibres of the dermis seem to be the major target of smoke components. To determine quantitative and qualitative changes of the dermal elastic tissue of non-sun-exposed skin induced by smoking, as well as the possible mechanisms responsible for them. Sixty-nine patients were recruited (20 nonsmokers, 19 former smokers and 30 smokers). Using static morphometry and immunohistochemistry and lectin staining we analysed elastic fibres of the dermis and their major components, elastin and microfibrillar component. Significantly higher values for the number of elastic fibres mm(-2) and the percentage of the area filled by them in the reticular dermis were found in smokers. Cumulative tobacco dose showed statistically significant correlations with both morphological parameters (Spearman's rank correlation coefficient). Immunohistochemistry demonstrated that the two main components of elastic fibres were altered in smokers. Plasma protease inhibitors and lectin staining were negative in all the samples. Smoking is an independent risk factor for the increase of elastic fibres in the reticular dermis of nonexposed skin, and it acts on their two main structural components, elastin and microfibrillar component. This increase in the area of elastic fibres in smokers is not due to newly synthesized elastic material, but to their degradation, as occurs in solar elastosis and which acts in an additive manner.

Fucoidan a sulfated polysaccharide from brown algae is a potent modulator of connective tissue proteolysis

Fucoidans are sulfated fucosylated polymers from brown algae cell wall that exhibit some heparin/heparan sulfate properties. We previously demonstrated that these polysaccharides were able in vitro to stimulate dermal fibroblast proliferation and extracellular matrix deposition. Here, we investigated the action of a 16 kDa fucoidan fraction on parameters involved in connective tissue breakdown. This fucoidan is able to inhibit gelatinase A secretion and stromelysin 1 induction by interleukin-1β on dermal fibroblasts in culture. Furthermore, we observed that fucoidan increases the rate of association of MMPs with their specific inhibitors namely TIMPs. Using tissue sections of human skin in ex vivo experiments, we evidenced that this polysaccharide was able to minimize human leukocyte elastase activity resulting in the protection of human skin elastic fiber network against the enzymatic proteolysis due to this serine proteinase. These results suggested that fucoidan could be used for treating some inflammatory pathologies in which uncontrolled extracellular matrix degradation takes place.

Multiple Roles for Elastic Fibers in the Skin

Dermal elastic fibers are believed to have a primary role in providing elastic stretch and recoil to the skin. Here we compare the structural arrangement of dermal elastic fibers of chick skin and different animal species. Most elastic fibers in chick skin are derived from cells that line the feather follicle and/or smooth muscle that connects the pterial and apterial muscle bundles to feather follicles. Elastic fibers in the dermis of animals with single, primary hair follicles are derived from cells lining the hair follicle or from the ends of the pili muscle, which anchors the muscle to the matrix or to the hair follicle. Each follicle is interconnected with elastic fibers. Follicles of animals with primary and secondary (wool) hair follicles are also interconnected by elastic fibers, yet only the elastic fibers derived from the primary follicle are connected to each primary follicle. Only the primary hair follicles are connected to the pili muscle. Human skin, but not the skin of other primates, is significantly different from other animals with respect to elastic fiber organization and probably cell of origin. The data suggest that the primary role for elastic fibers in animals, with the possible exception of humans, is movement and/or placement of feathers or hair.

Pregnancy and obstetrical outcomes in pseudoxanthoma elasticum

Pseudoxanthoma elasticum (PXE) is a genetic multisystem disorder characterized by calcified dystrophic elastic fibres in skin, retina and arteries. Much of the earlier literature on pregnancy in PXE contained reports of severe complications, leading some healthcare providers to advise women with PXE against becoming pregnant and some women with PXE to avoid pregnancy. To evaluate the obstetrical outcomes and the incidence of pregnancy complications in women with PXE and to determine if pregnancy is associated with an adverse effect on the course of the disease. Women with PXE (n = 407) answered detailed questionnaires regarding reproductive history and pregnancy as well as the course of their disease. The frequency of reported pregnancy outcomes and complications was determined. Severity indices for the major clinical manifestations of PXE were developed and correlated with gravidity of affected women aged 40 years or over. Among the 306 respondents with PXE who had ever been pregnant, there were 795 pregnancies. Of these, 83% ended in live births and 1% in stillbirth. The median birth weight was within the normal range and the incidence of low birth weight for gestation was low. Hypertension occurred in 10% of pregnancies, gastric bleeding and retinal complications in < 1%, and 12% of pregnancies were associated with worsening of skin manifestations. There was no effect of gravidity and clinical severity on cutaneous (P = 0.07), ocular (P = 0.59) or cardiac (P = 0.42) manifestations of PXE in women aged 40+ years, nor did ever having been pregnant adversely affect these clinical severity indices. Of the 101 women who had never been pregnant, 17% made the decision because they were advised against becoming pregnant by a healthcare professional and 11% did not become pregnant because they feared an adverse outcome either in their pregnancy or disease. PXE is not associated with markedly increased fetal loss or adverse reproductive outcomes. The incidence of gastric bleeding, although probably higher than in the unaffected population, is much lower than previously reported, and retinal complications are uncommon. Although a few pregnancies were associated with worsening of skin manifestations, there was no correlation of either gravidity or ever having been pregnant with ultimate severity of skin, ocular or cardiovascular manifestations. There is no basis for advising women with PXE to avoid becoming pregnant, and most pregnancies in PXE are uncomplicated.

The presence of d-β-aspartic acid-containing peptides in elastic fibers of sun-damaged skin: a potent marker for ultraviolet-induced skin aging

Biologically uncommon d-aspartyl residues have been reported in proteins of various elderly tissues. We prepared a polyclonal antibody against d-β-Asp-containing peptide and examined its immunoreactivity in the skin. The antibody recognized integrated or disintegrated elastic fibers in the sun-exposed skin but not in the sun-protected skin of the elderly donors. Western blot analysis of the proteins isolated from sun-damaged skin demonstrated that the 50 kDa protein was immunoreactive with both antibodies for d-β-Asp-containing peptide and elastin. Ultraviolet (UV) irradiation on normal skin caused the appearance of d-β-Asp-containing peptide-immunoreactive fibers in the dermis. These results suggest that UV irradiation is closely related to the formation of d-β-Asp in the elastic fibers of skin. We propose that the antibody could be a useful indicator for sun damage of the skin.

A novel Q378X mutation exists in the transmembrane transporter protein ABCC6 and its pseudogene: implications for mutation analysis in pseudoxanthoma elasticum.

Pseudoxanthoma elasticum (PXE) is an inherited disorder of the elastic tissue with characteristic progressive calcification of elastic fibers in skin, eye, and the cardiovascular system. Recently mutations in the ABCC6 gene, encoding a transmembrane transporter protein, were identified as cause of the disease. Surprisingly, sequence and RFLP analysis for exon 9 with primers corresponding to flanking intronic sequence in diseased and haplotype negative members from all of our families and in a control population revealed either a homozygous or heterozygous state for the Q378X (1132C-->T) nonsense mutation in all individuals. With the publication of the genomic structure of the PXE locus we had identified the starting point of a large genomic segmental duplication within the locus in the cytogenetic interval defined by the Cy19 and Cy185 somatic cell hybrid breakpoints on chromosome 16p13.1. By means of somatic cell hybrid mapping we located this starting point telomeric to exon 10 of ABCC6. The duplication, however, does not include exon 10, but exons 1-9. These findings suggest that one or several copies of an ABCC6 pseudogene (psiABCC6) lie within this large segmental duplication. At least one copy contains exons 1-9 and maps to the chromosomal interval defined by the Cy163 and Cy11 breakpoints. Either this copy and/or an additional copy of psiABCC6 within Cy19-Cy183 carries the Q378X mutation that masks the correct identification of this nonsense mutation as being causative in pseudoxanthoma elasticum. Long-range PCR of exon 9 starting from sequence outside the genomic replication circumvents interference from the psiABCC6 DNA sequences and demonstrates that the Q378X mutation in the ABCC6 gene is associated with PXE in some families. These findings lead us to propose that gene conversion mechanisms from psiABCC6 to ABCC6 play a functional role in mutations causing PXE.

Pseudoxanthoma elasticum: Point mutations in the ABCC6 gene and a large deletion including also ABCC1 and MYH11

Pseudoxanthoma elasticum (PXE) is a mendelian disorder characterized by calcification of elastic fibers in skin, arteries, and retina. It results in dermal lesions, arterial insufficiency and retinal hemorrhages, leading to macular degeneration. PXE is transmitted either as an autosomal dominant or recessive trait and several sporadic cases have been observed. Mutations in the ABCC6 gene have been identified very recently in patients. Here, we report on a large Italian family affected by pseudoxanthoma elasticum for which linkage analysis had pointed to a region encompassing markers D16S3069-D16S405-D16S3103; hemizygosity of marker D16S405 allowed us to detect a submicroscopic deletion of at least 900 kb involving ABCC6, ABCC1, and MYH11. Mutation analysis on the other allele of the family, as well as on two additional sporadic cases, revealed nonsense (Y227X, R518X, R1164X) and frame-shift (c.960delC) mutations in ABCC6 (MRP6) further confirming the role of this multi-drug resistance gene in the etiology of pseudoxanthoma elasticum. Furthermore, clinical re-examination of members of the family harboring the deletion led to the detection of additional features, potentially caused by the deletion of the MYH11 gene. In the course of the analysis five nonpathogenic variants were found in ABCC6: 1233T>C, 1245G>A, 1838 T>G (V614A), 1890C>G, and 3506+83C>A. Hum Mutat 18:85, 2001.

Mutations in a gene encoding an ABC transporter cause pseudoxanthoma elasticum.

Pseudoxanthoma elasticum (PXE) is a heritable disorder characterized by calcification of elastic fibres in skin, arteries and retina that results in dermal lesions with associated laxity and loss of elasticity, arterial insufficiency and retinal haemorrhages leading to macular degeneration. PXE is usually found as a sporadic disorder, but examples of both autosomal recessive and autosomal dominant forms of PXE have been observed. Partial manifestations of the PXE phenotype have also been described in presumed carriers in PXE families. Linkage of both dominant and recessive forms of PXE to a 5-cM domain on chromosome 16p13.1 has been reported (refs 8,9). We have refined this locus to an 820-kb region containing 6 candidate genes. Here we report the exclusion of five of these genes and the identification of the first mutations responsible for the development of PXE in a gene encoding a protein associated with multidrug resistance (ABCC6).

Mutations of the gene encoding the transmembrane transporter protein ABC-C6 cause pseudoxanthoma elasticum.

We recently published the precise chromosomal localization on chromosome 16p13.1 of the genetic defect underlying pseudoxanthoma elasticum (PXE), an inherited disorder characterized by progressive calcification of elastic fibers in skin, eye, and the cardiovascular system. Here we report the identification of mutations in the gene encoding the transmembrane transporter protein, ABC-C6 (also known as MRP-6), one of the four genes located in the region of linkage, as cause of the disease. Sequence analysis in four independent consanguineous families from Switzerland, Mexico, and South Africa and in one non-consanguineous family from the United States demonstrated several different mis-sense mutations to cosegregate with the disease phenotype. These findings are consistent with the conclusion that PXE is a recessive disorder that displays allelic heterogeneity, which may explain the considerable phenotypic variance characteristic of the disorder.

Analysis of the ex vivo specificity of human gelatinases A and B towards skin collagen and elastic fibers by computerized morphometry.

Cutaneous aging and chronic exposure to UV irradiation leads to alterations in the appearance and biochemical composition of the skin. Members of the MMP family have been involved in the destruction of the extracellular matrix. Among them, gelatinases A and B were found to display elastolytic activity, in vitro. In this study, we first determined the ex vivo elastolytic potential of both endopeptidases, using human skin tissue sections and computerized morphometric analyses, and compared it with those of neutrophil elastase. In such conditions, gelatinase B (50 nM) induced 50% elastolysis. The percentage of elastic fibers degraded by gelatinase A (10-100 nM) never exceeded 10%. Elastolysis by gelatinase B and leukocyte elastase was characterized by a decrease in fiber length and an increase in the average diameter of the fibers. In addition, gelatinase B exhibited fibrillin-degrading activities. On the contrary, gelatinase A (50 nM) elicited up to 50% hydrolysis of collagen fibers, preferentially degrading type III collagen fibers. Gelatinase B did not promote any collagen degrading activity. Our data suggested that in vivo gelatinases could disrupt most extracellular matrix structures of human skin. Gelatinase B and to a much lesser extent, gelatinase A would degrade components of the elastic fibers network while gelatinase A, but not gelatinase B, would alter mostly collagen fibers and also degrade constituents of the dermo-epidermal junction.

Elastin gene deletions in Williams syndrome patients result in altered deposition of elastic fibers in skin and a subclinical dermal phenotype.

Williams syndrome (WS) is a complex developmental disorder with multisystem involvement known to be the result of a microdeletion in the q11.23 region of chromosome 7. This deletion involves several genes, including the elastin gene. Although elastic fibers are important constituents of skin, little is known about the skin phenotype in WS patients. We have therefore studied the skin of four WS patients in which we've shown the deletion of one copy of the elastin gene. Physical examination and indirect immunofluorescent microscopy of elastin did not detect any major phenotypic or morphologic changes in the skin. We were able, however, to show subtle textural changes in skin and, by electron microscopy, that the amorphous component of elastic fibers in WS patients was consistently reduced when compared to normal controls. These findings indicate that deletion of one copy of the elastin gene results in reduced deposition of elastin in dermal elastic fibers, an altered elastic fiber ultrastructure, and a subclinical dermal phenotype in the children and young adult patients analyzed in this study.