Dermal Elastic Fibers Research Articles

Inhibition of ultraviolet-B-induced wrinkle formation by an elastase-inhibiting herbal extract: implication for the mechanism underlying elastase-associated wrinkles.

Previously, we have demonstrated that fibroblast-derived elastase plays an essential role in the increased three-dimensional tortuosity of elastic fibers, contributing to the loss of skin elasticity in UV-B-exposed skin. This decrease in skin elasticity is closely associated with the formation of wrinkles induced by UV exposure. To further clarify the role of elastase in the formation of wrinkles induced by UV exposure, we assessed the effects of an extract of Zingiber officinale (L.) Rose (which inhibits fibroblast-derived elastase) on the wrinkle formation induced by chronic UV-B irradiation. Topical application of an extract of Zingiber officinale (L.) Rose to rat or hairless mouse skin significantly inhibited the wrinkle formation induced by chronic UV-B irradiation at a suberythemal dose, which was accompanied by a significant prevention of the decrease in skin elasticity in both types of animal skin. In the rat hind limb skin, consistent with the inhibition of reduced skin elasticity, wrinkle prevention occurred concomitantly with a significant decrease in the curling and three-dimensional tortuosity of dermal elastic fibers. Our results indicate that herbal extracts with an ability to inhibit fibroblast-derived elastase may prove to be effective as anti-wrinkling agents, confirming the important role of elastase in UV-B-induced wrinkle formation.

Granulomatous Dermatitis with Enlarged Histiocytes: A Characteristic Pattern of Granulocyte Colony-Stimulating Factor

Two patients developed a pruritic maculopapular rash following treatment with granulocyte colony-stimulating factor (G-CSF). Histopathological examination disclosed a superficial dermal inflammatory infiltrate composed of interstitially arranged large histiocytic CD68+ cells and perivascularly disposed lymphocytes. Large histiocytes were interspersed among the collagen bundles with associated slight deposits of mucin. Elastophagocytosis was occasionally observed, and a slight reduction of dermal elastic fibers was also noted. There was no evidence of frank granuloma formation, fibrosis or significant changes of collagen bundles. This histopathological variant of granulomatous dermatitis with ‘enlarged histiocytes’ seems to be characteristic of an unusual cutaneous reaction secondary to CSF treatment.

Dermal elastic fibres in the inherited hypermobile disorders

Elastic fibres in the inherited hypermobile disorders are probably abnormal on the inherited grounds. The abnormality may contribute for diagnosis and investigation of connective tissue biology. The abnormality will be specific for every disorders and disclosed in the age-dependent change when exposure-dependent change was excluded. Skin specimens from Ehlers-Danlos syndrome and hypermobile syndrome, Marfan syndrome, Osteogenesis imperfecta type I, homocysteinuria and normal controls are studied by routine electron microscopy. Age-dependent ultrastructural change of broad elastic fibres was evaluated in reticular dermis. Age-dependent change was categorized in infantile, adolescent, adult and senile pattern. Infantile pattern showed normal ultrastructure. Degeneration was first found in adolescent pattern by disarrayed microfibrils and degenerate matrix. Degeneration proceeded in adult pattern and ended in senile pattern. Typical abnormality developed in adult pattern. Ehlers-Danlos syndrome and hypermobile syndrome showed no specific abnormality but the degeneration began earlier and was severer than the control. Marfan syndrome showed defects of microfibrils and matrix surface. Moth-eaten figure was characteristic. Osteogenesis imperfecta showed abnormal matrix and revealed homogenous bulges of matrix. Homocysteinuria was specified by numerous microfibrils on the matrix surface in infantile pattern. Abnormality of elastic fibre was recognized in the reticular dermis of elbow. Ehlers-Danlos syndrome and hypermobile syndrome showed no specific abnormality but the degeneration was more intensive than the control. Abnormality of Marfan syndrome was degeneration of elastic microfibrils and matrix surface, Osteogenesis imperfecta was characterized by excess amount of matrix. Homocysteinuria revealed numerous microfibrils. Ultrastructural abnormality provided grounds for studies on histopathology and biology of elastic fibre.

Augmentation of UV-induced skin wrinkling by infrared irradiation in hairless mice

Skin aging can be divided into intrinsic aging and photoaging. Sunlight is a major cause of photoaging, and is composed of ultraviolet (UV) and infrared (IR) radiation. Although the effects of UV radiation on skin aging have been widely studied, little is known about the biological effects of IR on the photoaging process in human skin. We found that chronic IR treatment induced wrinkles in hairless mice, and augments UV-induced wrinkle formation and UV-induced skin thickening in hairless mice. Histologically, we found that IR treatment augments UV-induced epidermal and dermal thickening, and that UV-induced increases of collagen and elastic fibers in dermis. Moreover, chronic IR treatment increased MMP-3 and MMP-13 mRNA expressions significantly in hairless mouse skin and augmented UV-induced MMP-3 and MMP-13 mRNA expressions and UV-induced MMP-2 and MMP-9 activities. From these results, we demonstrate that IR alone induces skin wrinkling and augments UV-induced wrinkle formation. Taken together, we suggest that IR plays an important role in the development of photoaging.

Relationships between lung function, smoking and morphology of dermal elastic fibres

To investigate the relationship between lung function and dermal elastic fibres in non-smokers and smokers with and without chronic obstructive pulmonary disease (COPD). A cross-sectional study was performed with lung function as the outcome [forced expiratory volume in the first second (FEV1)%, FEV1/forced vital capacity (FVC)% and residual volume (RV)/total lung capacity (TLC)%] and smoking (pack-years) and morphology of dermal elastic fibres (fibres/mm(2) and percentage histologic field filled with them) as independent variables, with assessment of the associations between these variables by univariate and multivariate testing. Sixty outpatients reporting chronic cough and/or phle\gm were enrolled (16 non-smokers/44 smokers; COPD: 26, 43.3%). Both lung function and elastic fibres in the reticular dermis (fibres/mm(2)r(s) = 0.36, percentage of the histologic field filled by elastic fibres r(s) = 0.48, P < or = 0.01) correlated with cumulative smoking (Spearman's rank correlation coefficient). Lung function parameters correlated with percentage of the histologic field filled by elastic fibres (FEV1%: r = -0.43; FEV1/FVC%: r = -0.36 and RV/TLC%: r = 0.43; P < or = 0.01, Pearson correlation coefficient), and COPD was significantly related to this morphologic parameter (odds ratio 1.26, 95% confidence interval 1.06-1.48; P = 0.006), associations that depended mainly on cumulative smoking. Lung function impairment with an obstructive pattern is associated with morphologic abnormalities in the reticular dermis appearing in the histologic section as an increase in the percentage of the field filled by elastic fibres. This relationship depends on cumulative smoking and suggests a common effect of smoking on the elastic fibres in both lung and skin.

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.

Carbon Dioxide Laser Resurfacing with Fast Recovery

ABTRACT: Long sun exposure, in addition to ozone layer damage, produces structural damase to the normal skin. Injury to the dermal collagen and elastic fiber results in facial wrinkles. Photodamage to the skin is one of the most common sources of concern for patients visiting the plastic surgeon or dermatologist. Over the years, many alternative solutions have been developed. CO2 laser treatment is one of the alternatives bringing unique benefits and satisfactory results for both patient and surgeons. However, the initial problems of emotional discomfort, prolonged postoperative recovery and delayed return to normal activities have made patients reluctant to accept this method. This article discusses single-pass CO2 laser resurfacing with lower energy. Also, it proposes a technique that does not use wet gauze to remove the surface of the skin. This technique is applied in combination with an intensive skin care treatment. Different authors propose a single pass of CO2 laser with excellent results. With the reported method, identical long-lasting benefits are achieved, but the post-operative time is shorter.

Heparan sulphate interacts with tropoelastin, with some tropoelastin peptides and is present in human dermis elastic fibers

A number of reports point to the presence of proteoglycans and/or glycosaminoglycans within elastic fibers in normal and in pathological conditions. We present data that heparan sulphate (HS)-containing proteoglycans are associated with normal elastic fibers in human dermis and that isolated HS chains interact in vitro with recombinant tropoelastin and with peptides encoded by distinct exons of the human tropoelastin gene (EDPs). By immunocytochemistry, HS chains were identified as associated with the amorphous elastin component in the human dermis and remained associated with the residual elastin in the partially degenerated fibers of old subjects. HS appeared particularly concentrated in the mineralization front of elastic fibers in the dermis of patients affected by pseudoxanthoma elasticum (PXE). In in vitro experiments, HS induced substantial changes in the coacervation temperature and in the aggregation properties of recombinant tropoelastin and of synthetic peptides (EDPs) corresponding to sequences encoded by exons 18, 20, 24 and 30 of the human tropoelastin gene. In particular, HS modified the coacervation temperature and favoured the aggregation into ordered structures of tropoelastin molecules and of EDPs 18, 20 and 24, but not of EDP30. These data strongly indicate that HS-elastin interactions may play a role in tissue elastin fibrogenesis as well as modulating elastin stability with time and in diseases.

Ovariectomy is sufficient to accelerate spontaneous skin ageing and to stimulate ultraviolet irradiation-induced photoageing of murine skin

Wrinkling and sagging of the skin during photoageing is physiologically associated with diminished elasticity, which can be attributed to increased fibroblast-derived elastase activity. This degrades the dermal elastic fibres needed to maintain the three-dimensional structure of the skin. We previously reported that ovariectomy accelerates ultraviolet (UV)B-induced wrinkle formation in rat hind limb skin by altering the three-dimensional structure of elastic fibres. In this study, we used hairless mice to assess the effects of ovariectomy with or without chronic UVA or UVB radiation on sagging and wrinkling of skin, on the elasticity of skin, as well as on matrix metalloproteinase activities in the skin. Ovariectomies or sham operations were performed on 6-week-old female ICR/HR hairless mice. Even in the ovariectomy group without UV irradiation, the skin elasticity was significantly decreased during the 3-13 weeks after ovariectomy, which was accompanied by a significant increase in elastase activity in the skin. After UVA or UVB irradiation, skin elasticity was significantly decreased to a greater extent in the ovariectomy group than in the sham operation group, and this was accompanied by a reciprocal increase in elastase activity but not in the activities of collagenases I or IV in the skin. Consistent with the decreased skin elasticity, UVA irradiation for 12 weeks elicited more marked sagging in the ovariectomy group than in the sham operation group. UVB irradiation for 12 weeks also induced more marked wrinkle formation in the ovariectomy group than in the sham operation group. These results suggest that ovariectomy alone is sufficient to accelerate skin ageing and to increase UV sensitivity, which results in the further deterioration of the skin and photoageing, and may account for the accelerated skin ageing seen in postmenopausal women.

Development of UV-induced squamous cell carcinomas is suppressed in the absence of SPARC.

SPARC (Secreted Protein Acidic and Rich in Cysteine) is a multifunctional glycoprotein belonging to a group of matrix-associated factors that mediate cell-extracellular matrix interactions but have no structural roles. In the present study we investigated the contribution of SPARC to factors that influence the development of skin tumors in response to UV irradiation. A hairless SPARC-null mouse was developed and compared to control SKH1 hairless mice in terms of skin tumor induction and extracellular matrix changes occurring in response to UV-irradiation. Following 23 weeks of exposure to UVB totaling 14.5 J per cm(2), tumor development in the wild-type mice was severe, with an average of over 20 tumors per mouse, many of which were squamous cell carcinomas. Conversely, the SPARC-null mice were strikingly tumor-resistant, developing no squamous cell carcinomas and averaging less than one small papilloma per mouse. SPARC was undetectable immunohistochemically in skin from the non-irradiated control group yet was present in relatively high quantities in the basal and superficial areas of the tumor mass. The SPARC-null mice also exhibited a limited contact hypersensitivity response and were refractory to UV induced immune suppression. In conclusion, SPARC appears to have a crucial role in mediating tumor formation in response to UV irradiation.

Deficiency of tenascin-X causes abnormalities in dermal elastic fiber morphology.

Deficiency of the extracellular matrix protein tenascin-X (TNX) was recently described as the molecular basis of a new, recessive type of Ehlers-Danlos syndrome. Here we report gross abnormalities of the elastic fibers and microfibrils in the dermis of these patients, and reduced dermal collagen content, as determined by quantitative image analysis. The ascending, fine elastic fibers in the papillary dermis were absent or inconspicuous and had few branches. The coarse elastic fibers of the reticular dermis were fragmented and clumped. At the ultrastructural level, irregular and immature elastin fibers and fibers devoid of microfibrils were observed. In TNX-deficient patients the dermal collagen density was reduced, but no structural abnormalities in the collagen fibrils were found. These findings suggest that both elastic fiber abnormalities and reduced collagen content contribute to the observed phenotype in TNX-deficient patients.

Connective tissue and aging

Human skin is composed of epidermal and dermal layers, each of which has its own functional importance. Dermis consist of a fine network of collagen fibers, elastic fibers, and other components of the extracellular matrix (ECM). ECM consist primarily of proteins and complex sugars, which form fibrillar networks and a ground substance. Collagen is an important structural component of skin connective tissue and provides the tensile strength of skin.Approximately 70–80% of the dry weight of skin consists of collagen. The most abundant collagen types in skin are types I and III; the former accounts for 80% of the total collagen content of skin and the latter for approximately 15%. The other collagen types present in skin include type IV collagen, which is abundant in the basement membrane (BM); type V collagen, which is located pericellularly; type VI collagen, which plays a role in matrix assembly and is present as microfibrils between collagen fibers; and type VII collagen, which is a structural component of anchoring fibrils. Elastin accounts for only about 1–2% of the dry weight of skin but is important for the maintenance of skin elasticity and resilience. Glycosaminoglycans are of central importance for the maintenance of a water balance in skin, even though the quantities in ECM are small (0.1–0.3% of the dry weight of skin).In the dermis fibroblasts are responsible for the synthesis of ECM proteins. The fibroblasts in the dermis spend majority of time in quiescent state. However in response to activation, the fibroblasts can be reactivated, and certain pool of cell is able to differentiate into myofibroblasts which have important role in repairing skin defects such as during wound healing. During aging the number of fibroblasts is markedly reduced.Also the response of fibroblasts to various growth factors and mechanical or pathological stimulates (wound healing) is diminished.Skin collagen synthesis declines with aging and as the result of such external factors as long‐term sun exposure and medications, for example, topical corticosteroids. In aging skin, collagen fibers become thicker and less soluble and the synthesis of collagen declines. Skin thickness remains quite constant between 20 and 70 years of age, after which a marked decrease in skin thickness occurs. During aging the expression of collagenases are increased and inhibitors of collagenases are reduced leading to increased proteolysis of connective tissue. Recent studies have shown that collagen synthesis is declined in the skin of heavy smokers, while collagenases are increased inducing premature skin aging.The elastic properties of skin are also affected by aging. Along with increasing age, dermal elastic fibers become thicker and fragmented and oxytalan fibers appear fragmented and shortened. Disintegration of elastic fibers is already seen in a minority of fibers between ages 30 and 70, but the changes become more profound after the age of 70 years, affecting a majority of the fibers. As a result of the decreased number of elastic fibers in aged skin, the elastic recovery of skin decreases in elderly people. Even though the content of GAGs and proteoglycans is relatively small, they have significant role in collagen fibril formation, water content of dermis and in mechanical properties. During aging there are marked alterations in different proteoglycans. The amount and synthesis of versican (high molecular size) is decreased and small molecular size decorin is increased. In photoaged skin versican is increased and is closely associated to elastin while decorin is decreased.

Mammographic findings in pseudoxanthoma elasticum

Background: There have been isolated case reports of arterial and skin calcification in mammograms of patients with pseudoxanthoma elasticum (PXE), and unpublished anecdotes of many women with PXE undergoing breast biopsy for evaluation of microcalcifications. Objective: Our aim was to systematically evaluate mammography and breast pathology in PXE. Methods: The mammograms of 51 women with confirmed PXE were compared with those of a control sample of 109 women without PXE, noting each of the following characteristics on each mammogram: breast density, skin thickening, skin microcalcifications, vascular calcification, breast microcalcifications and macrocalcifications, and masses. The characteristics of the 2 samples were compared using the 2-tailed t test with a pooled estimate of variance. The indications for mammography and data for each of the mammographic findings were analyzed using the χ2 test. Available breast biopsy material was reviewed. Results: The PXE and control groups were similar in age and indications for mammography. There was a statistically significant increase in skin thickening, vascular calcification, and breast microcalcifications in the PXE group (P < .001 each). Breast density, masses, macrocalcifications, and skin calcification did not differ statistically in the 2 groups, but no control patient had axillary calcification, or both vascular calcification and microcalcifications (P < .001). Nearly 1 in 7 of the patients with PXE demonstrated at least 3 of the following: microcalcifications, skin calcifications, vascular calcification, and skin thickening; whereas none of the control group did. Histopathologic findings of breast tissue showed calcification of dermal elastic fibers, subcutaneous arteries, and elastic fibers of the deep fascia and interlobular septae of the fat adjacent to breast parenchyma. Conclusion: Breast microcalcification and arterial calcification are not rare in the normal population and are not of diagnostic value. The presence of both of these findings, especially with skin thickening or axillary skin calcification, should suggest a diagnosis of PXE. The majority of breast calcifications in PXE are benign. (J Am Acad Dermatol 2003;48:359-66.)

シワ形成メカニズムと予防 光老化によるシワの形成機序とその予防

A series of our studies demonstrated that wrinkling on the human face is initiated at the eye corner which is the most frequently sun-exposed area. The depth of the wrinkling was found to be paralleled by the diminished elastic property in the same area, indicating that a significant decrease in the skin elasticity is mainly responsible for the formation of wrinkling. In our studies using rat hind limb skins for elucidating the causative factors of the reduced elasticity, we found that wrinkle formation in the skin following long-term UVB irradiation was accompanied by decreases in skin elasticity and the concomitant curling of elastic fibers in the dermis which suggested that the tortuosity of dermal elastic fibers is an important determinant in reducing the skin elasticity. Since the damage in three dimensional elastic fiber structures seems to be attributable to the partial digestion by elastases, the degradative enzymes for elastic fibers, whose activities in the dermis were enhanced by repeated UVB irradiations, we determined whether the inhibition of elastase activity in vivo would prevent the damage of dermal elastic fibers and might eradicate wrinkle formation associated with the loss of skin elasticity. Because the major elastase in the skin under non-inflammatory onditions is skin fibroblast elastase, we used a specific inhibitor of that enzyme to assess its biological role in wrinkle formation. The hind limb skins of Sprague-Dawley rats or hairless mice were irradiated with UVB at a suberythemal dose 3 times a week for 6 weeks. During that period, 0.1-10.0 mM N-phenetylphosphonyl-leucyl-tryptophane (NPLT), an inhibitor of skin fibroblast elastase, was applied topically 5 times a week. NPLT application at concentrations of 0.1-1.0 mM eradicated wrinkle formation in a dose-dependent manner, with a peak for inhibition at 1.0mM. This inhibition was accompanied by a continued low tortuosity of dermal elastic fibers and a maintenance of skin elasticity. These findings suggest that skin fibroblast elastase plays an essential role in the degeneration and /or tortuosity of elastic fibers induced by cumulative UVB irradiation and that its inhibition would provide a desirable model for preventing sun-induced wrinkling. [Skin Cancer (Japan) 2003; 18: 157-164]

Anetoderma: an altered balance between metalloproteinases and tissue inhibitors of metalloproteinases.

The amount of elastic fibers from lesional and healthy skin areas of five patients with anetoderma was determined by automated image analysis. Dermal elastic fibers were almost completely absent in anetodermic skin and preelastic fibers were undetectable or extremely rare. Organ cultures were performed using explants from affected and unaffected skin areas of the same patient. We identified and quantified proteases in the culture media of explants: MMP-1 (collagenase 1), MMP-2 and MMP-9 (gelatinases A and B), MMP-3 (stromelysin 1), MMP-7 (matrilysin 1), and tissue inhibitors of metalloproteinases, TIMP-1 and TIMP-2. The data were compared with those of two healthy donors. For the five samples of anetodermic skin, MMP-1 levels were significantly higher compared with the uninvolved cultures and the two healthy samples. A significant increase of TIMP-1 expression was also observed in the affected cultures. We demonstrated a significant increase in the production of gelatinase A in lesional skin when compared with nonlesional skin and healthy donor samples. We found no significant production of TIMP-2 in the five samples of anetodermic skin compared with the samples from the two healthy donors. There was a significant decrease in TIMP-2 expression in the five nonlesional samples compared with the control samples. These data are in favor of an altered balance in anetodermic patients between MMP-2 and TIMP-2. Levels of MMP-9, MMP-3, and MMP-7 were significantly higher in the culture-conditioned media of the anetodermic skin samples than the nonlesional skin cultures. Because MMP-3, MMP-7, MMP-9 are known to degrade elastin, and MMP-3 can activate the latent forms of MMP-7 and MMP-9, we propose that these metalloproteinases also participate in the degradation of elastic fibers in anetodermic skin.

Vitronectin in the cirrhotic liver: An immunomarker of mature fibrosis

Vitronectin (Vn) is a multifunctional plasma glycoprotein produced by hepatocytes. Vn has been studied extensively as a cell adhesion molecule. However, its localization in the hepatic extracellular matrix has received relatively little attention. Cryosections of 5 normal liver samples and of 20 specimens showing posthepatitic cirrhosis were stained by the avidin–biotin complex method with a well-characterized monoclonal antibody to Vn. The extent and intensity of immunostaining were assessed semiquantitatively (0, no staining; 1+, weak focal staining; 2+, strong focal staining; 3+, strong diffuse staining). Paraffin sections from the same samples were stained with Masson trichrome (MT) and Shikata orcein (Or) methods. Frozen samples from selected cases were analyzed by Western blotting. In the normal liver, 3+ staining was limited to portal vessels. The portal tract connective tissue showed minimal staining (0 to 1+). Cirrhotic septa showed strong staining (2+). Septa lacking significant inflammation and composed of dense connective tissue, as indicated by MT and Or stains, showed the strongest Vn reactions (3+). Immunoblotting data strongly correlated with Vn increase in cirrhotic livers. Vn immunoreactivity is markedly increased in the cirrhotic liver matrix, regardless of the documented decrease in plasma Vn. Binding to collagen, elastin, and proteoglycans is the current favored mechanism of Vn deposition in tissues. Previous studies in cirrhotic patients showed increased affinity of plasma Vn to collagen. Vn is also increased in aged skin, associated with dermal elastic fibers. In other tissues, Vn deposition reflects chronicity of injury. Therefore, Vn immunoreactivity in liver can be considered a marker of fibrosis, especially of chronic/mature fibrosis, paralleling previous observations on enhanced orcein staining of cirrhotic septa. Immunolabeling of biopsy specimens with Vn and tenascin, a marker of ongoing remodeling or recently formed fibrous tissue, could be diagnostically helpful. HUM PATHOL 32:1356-1362. Copyright © 2001 by W.B. Saunders Company

Selective Inhibition of Skin Fibroblast Elastase Elicits a Concentration-Dependent Prevention of Ultraviolet B-Induced Wrinkle Formation

We previously reported that wrinkle formation in the skin following long-term ultraviolet B irradiation is accompanied by decreases in skin elasticity and the curling of elastic fibers in the dermis. We further showed that wrinkles could be repaired by treatment with retinoic acid and that this was concomitant with the recovery of skin elasticity ascribed to the repair of damaged elastic fibers. Those studies suggested that decreasing the tortuosity of dermal elastic fibers is an important factor involved in inhibiting or repairing wrinkle formation. Therefore, it is of particular interest to determine whether the inhibition of elastase activity in vivo would prevent the damage of dermal elastic fibers and might abolish wrinkle formation associated with the loss of skin elasticity. Because the major elastase in the skin under noninflammatory conditions is skin fibroblast elastase, we used a specific inhibitor of that enzyme to assess its biologic role in wrinkle formation. The hind limb skins of Sprague-Dawley rats were irradiated with ultraviolet B at a suberythemal dose three times a week for 6 wk. During that period, 0.1-10.0 mM N-phenetylphosphonyl-leucyl-tryptophane, an inhibitor of skin fibroblast elastase, was applied topically five times a week. N-phenetylphosphonyl-leucyl-tryptophane application at concentrations of 0.1-1.0 mM abolished wrinkle formation in a concentration-dependent manner, with a peak for inhibition at 1.0 mM. This inhibition was accompanied by a continued low tortuosity of dermal elastic fibers and a maintenance of skin elasticity. Measurement of elastase activity after 6 wk of ultraviolet B irradiation demonstrated that whereas phosphoramidon-sensitive elastase activity was significantly enhanced in the ultraviolet B-exposed skin, there was no significant increase in that activity in the ultraviolet B-exposed, N-phenetylphosphonyl-leucyl-tryptophane-treated skin. These findings suggest that skin fibroblast elastase plays an essential part in the degeneration and/or tortuosity of elastic fibers induced by cumulative ultraviolet B irradiation.

In this Issue

In this Issue

Morphometric analysis of elastic skin fibres from patients with: cutis laxa, anetoderma, pseudoxanthoma elasticum, and Buschke–Ollendorff and Williams–Beuren syndromes

Computed morphometric analysis of elastic skin fibres in patients with cutis laxa, anetoderma, Williams-Beuren syndrome, pseudoxanthoma elasticum (PXE), and Buschke-Ollendorff syndrome, all clinically ascertained, was performed and compared with data obtained from healthy individuals of the same age. The diameters, area fractions (AA%) and volume fractions (VV%) occupied by pre-elastic fibres and dermal elastic fibres were determined. Irrespective of age the diameter of dermal elastic fibres followed a Gaussian distribution for all groups studied. These diameters were taken into consideration for VV% determinations. Compared with data from skin of healthy subjects of similar age range, VV% of pre-elastic fibres was significantly decreased in patients with cutis laxa, anetoderma, Williams-Beuren syndrome, and PXE and undetectable in Buschke-Ollendorff patients. VV% of dermal elastic fibres was four- to fivefold increased in Buschke-Ollendorff syndrome, two- to threefold increased in PXE skin, four- to fivefold decreased in cutis laxa and anetoderma skin and about twofold decreased in Williams-Beuren skin. The diameter of oxytalan fibres was decreased in anetoderma and Williams-Beuren syndrome while oxytalan fibre diameter was unchanged in PXE and cutis laxa. The diameter of dermal elastic fibres was increased in PXE and Buschke-Ollendorff syndrome, but was decreased in anetoderma and Williams-Beuren syndrome and unchanged in cutis laxa. We demonstrated that cutis laxa, anetoderma, Williams-Beuren syndrome, PXE, and Buschke-Ollendorff syndrome could be easily differentiated by morphometric analysis of elastic skin fibres. Thus we propose that morphometric analyses together with skin biopsies are a valuable tool for distinguishing between inherited and/or acquired skin diseases known to display alterations of elastic fibres.

Carbon dioxide laser treatment promotes repair of the three-dimensional network of elastic fibres in rat skin.

We have previously reported that ultraviolet (UV) B irradiation induces a loss of linearity in the three-dimensional structure of dermal elastic fibres, which results in the reduction of elastic properties of the skin and leads to wrinkle formation. We further reported that repair of wrinkles by all-trans retinoic acid is accompanied by recovery of the linearity of elastic fibres. Carbon dioxide (CO2) lasers are widely used for treating wrinkles in cosmetic surgery. To perform CO2 laser treatment of wrinkles induced in rat skin by UVB irradiation and to evaluate changes in the three-dimensional structure of dermal elastic fibres during wrinkle repair. Wrinkles were induced in the hind limb skin of Sprague-Dawley rats by UVB irradiation (130 mJ cm-2 three times weekly for 6 weeks), followed by CO2 laser treatment (11.3 J cm-2). The surface appearance of the skin was evaluated by replica observation 6 and 10 weeks after CO2 laser treatment followed by measurement of mechanical properties using a Cutometer. Subsequently, perfusion fixation and digestion with formic acid were performed and elastic fibres were observed by scanning electron microscopy (SEM). Image analysis of SEM micrographs was carried out to evaluate the linearity in the three-dimensional structure of elastic fibres. Six weeks after CO2 laser treatment, all parameters of skin mechanical properties in the UVB-irradiated group recovered to levels of the control non-irradiated group, accompanied by repair of wrinkles and a significant increase in linearity of the three-dimensional structure of elastic fibres. These findings indicate that CO2 laser treatment has a therapeutic potential to repair wrinkles to non-irradiated levels through recovery of the three-dimensional structure of elastic fibres.