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Cytokine Effects on Extracellular Matrix
Published in Jason Kelley, Cytokines of the Lung, 2022
Ganesh Raghu, Michael Kinsella
The elastic properties of many tissues, including the lung, are due to the presence of elastic fibers in the extracellular space. These fibers are found preponderantly in the pleura, parenchyma, and in walls of blood vessels and airways (Pierce and Hocott, 1960). The fibers comprise two distinct constituents: a more abundant amorphous component and the microfibrillar component. The latter is found in 10- to 12-mm fibrils that are located primarily around the periphery of the amorphous component, but, to some extent, are interspersed within it. The protein elastin makes up the highly insoluble amorphous component and is responsible for the elasticity of the fiber. Elastin exists in the parenchyma of the lung in a proportion of approximately 25–30% of ECM. Elastin is composed largely of glycine, proline, and hydrophobic amino acids. Multiple lysine-derived cross-links, such as the desmosines, link the individual polypeptide chains of elastin into a rubberlike network (Rosenbloom, 1984).
Comparative Anatomy, Physiology, and Biochemistry of Mammalian Skin
Published in David W. Hobson, Dermal and Ocular Toxicology, 2020
Elastic fibers are found in tissues that are capable of expansion. Elastic fibers consist of two protein components; elastin which is the main component and an amorphous substance, and a microfibrillar protein which acts as a mold for the elastin. Elastin is synthesized in fibroblasts similarly to collagen. Microfibrils are first formed by the fibroblasts and act as a mold for the newly formed elastin which then become a fiber. Ultrastructurally, elastic fibers do not exhibit a periodicity like collagen fibers. Elastic fibers stained for electron microscopy appear as an amorphous mass, with a few discrete microfibrils appearing at the periphery. This mass is usually light staining, while the microfibrils are more electron dense.38,199,202,204,206
Hormonal Effects on Fascia in Women
Published in David Lesondak, Angeli Maun Akey, Fascia, Function, and Medical Applications, 2020
Angeli Maun Akey, Kathleen O’Neil-Smith
Fascia, at the microscopic level, has hormonal receptors that can affect the body’s mechanical properties on a macroscopic level.28 In pregnancy and at the end of the follicular phase of the menstrual cycle, the sex steroid hormones progesterone and estrogen induce components of the extracellular matrix (ECM), namely expression of collagen, elastin, and fibrillin 1.29,30 Collagen is responsible for the stiffness of connective tissue while elastin and fibrillin are responsible for its stretchiness.3 Both elastin and fibrillin are elastic fiber components.30 Fibroblasts secrete the glycoprotein fibrillin, which increases fascial elasticity.31 Recall the clinical consequences of tissue collagen weakness as seen in Ehlers-Danlos syndrome, which results from defects in the genetic coding of collagen synthesis,31 and the hypermobility seen in Marfan syndrome, which results from a genetic mutation in the fibrillin-1 gene causing defects in fibrillin-1 synthesis.32
Evaluation of the changes in sebum, moisturization and elasticity in acne vulgaris patients receiving systemic isotretinoin treatment
Published in Cutaneous and Ocular Toxicology, 2021
Güllü Gencebay, Özge Aşkın, Server Serdaroğlu
The skin elasticity is determined by its composition of collagen and elastic fibres and these proteins may be destroyed with aging, leading to decreased elasticity33. Numerous studies showed that the skin elasticity is reduced with aging34–37. Some of the previous studies demonstrated that there was no difference between the genders in terms of skin elasticity38, however Firoos et al. showed that the skin elasticity was higher in females compared the males, yet this difference was statistically insignificant39. Bailey et al. demonstrated that the trunk skin elasticity was increased in female patients compared to male patients40. Although there are many studies evaluating the change in skin elasticity with ageing, there are only a few studies evaluating the skin elasticity in patients with acne vulgaris. Kim et al. evaluated 30 male and 30 female patients and have showed that there was a negative correlation between the number of pores and the skin elasticity in the facial region of male patients: as the number of pores increased, the skin elasticity decreased41. Another study investigating the skin sebum and elasticity demonstrated that the skin elasticity decreased and the number and size of the pores increased with aging. Again, this study demonstrated a statistically significant relationship between skin sebum levels and skin elasticity. Furthermore, the same study showed that the use of topical antiageing products could lead to a decline in the number and sizes of pores and an increase in the skin elasticity11.
Surgical and Immunohistochemical Outcomes of Scleral Reconstruction with Autogenic, Allogenic and Xenogenic Grafts: An Experimental Rabbit Model
Published in Current Eye Research, 2020
Gamze Dereli Can, Gülben Akcan, Mehmet Erol Can, Özge Ekin Akdere, Sevil Çaylı, Gülçin Şimşek, Menemşe Gümüşderelioğlu
Elastic fibers were irregularly located between the thick collagen lamella as a thin, long fiber network. On behalf of the elastic fiber density score, the lowest values were observed both in negative control and xenogenic HAM groups for all desired time points. In pairwise comparisons the elastin score of negative control and xenogenic HAM groups were significantly lower than both the normal control (p < .001) and autogenic PRF (p < .001) groups on day 7. Likewise, the elastin score of negative control and xenogenic HAM groups were significantly lower than both the normal control (p < .05) and autogenic PRF (p < .05) groups on day 28. The difference between the xenogenic HAM and both the positive and autogenic PRF groups remained on day 56 (p < .05). All other pairwise comparisons were not statistically significant (p > .05) (Figure 3c).
Severe elastolysis in hereditary gelsolin (AGel) amyloidosis
Published in Amyloid, 2020
Susanna Koskelainen, Fang Zhao, Hannu Kalimo, Marc Baumann, Sari Kiuru-Enari
Tissue elasticity is based on elastic fibres, which are insoluble components of the connective tissue, for example in skin and blood vessels. Elastic fibres are assembled during mid-gestation and designed to maintain their function for a lifetime [24]. Elastic fibres are formed of an amorphous, crosslinked elastin core and a surrounding fibrillin-rich microfibrillar mantle [24]. Elastin is the most abundant protein in mature elastic fibres, comprising approximately 90% of the structure [25]. It is extremely stable and relatively resistant to proteinases, including aggressive proteolytic enzymes known as elastases [26]. Therefore, the degradation of mature elastin normally progresses very slowly, over years or decades. Elastolysis is assumed to be the result of a disturbance in the normal balance between proteinases and their inhibitors [27]. It is observed, for example, in vessel walls during ageing and atherosclerosis [28].