Elastic fibers: formation, function, and fate during aging and disease

Control of epithelial tissue organization by mRNA localization

mRNA localization to specific subcellular regions is common in mammalian cells but poorly understood in terms of its physiological roles. This study demonstrates the functional importance of Net1 mRNA, which we find prominently localized at the dermal-epidermal junction (DEJ) in stratified squamous epithelia. Net1 mRNA accumulates at DEJ protrusion-like structures that interact with the basement membrane and connect to a mechanosensitive network of microfibrils. Disrupting Net1 mRNA localization in mouse epithelium alters DEJ morphology and keratinocyte-matrix connections, affecting tissue homeostasis. mRNA localization dictates the cortical accumulation of the Net1 protein and its function as a RhoA GTPase exchange factor (GEF). Altered RhoA activity is in turn sufficient to alter the ultrastructure of the DEJ. This study provides a high-resolution in vivo view of mRNA targeting in a physiological context. It further demonstrates how the subcellular localization of a single mRNA can significantly influence mammalian epithelial tissue organization, thus revealing an unappreciated level of post-transcriptional regulation that controls tissue physiology.

Toward a rational therapeutic for elastin related disease: Key considerations for elastin based regenerative medicine strategies

Elastin is a connective tissue protein, produced from the ELN gene, that provides elasticity and recoil to tissues that stretch, such as the large arteries of the body, lung parenchyma, skin, ligaments and elastic cartilages. It is produced as a soluble monomer, tropoelastin, that when cross-linked in the extracellular space generates a polymer that is extraordinarily stable, with a predicted half-life of >70 years. Although data suggest ongoing elastin transcription, it is rare to see new elastin deposited outside of its tight developmental window. Consequently, elastin-related disease comes about primarily in one of three scenarios: (1) inadequate elastin deposition, (2) production of poor-quality elastic fibers, or (3) increased destruction of previously deposited elastin. By understanding the pathways controlling elastin production and maintenance, we can design new therapeutics to thwart those abnormal processes. In this review, we will summarize the diseases arising from genetic and environmental alteration of elastin (Williams syndrome, supravalvar aortic stenosis, autosomal dominant cutis laxa, and ELN-related vascular and connective tissue dysfunction) and then describe the mechanisms controlling elastin production and maintenance that might be manipulated to generate novel therapeutics aimed at these conditions. We will end by summarizing existing therapeutic strategies targeting these disease mechanisms before outlining future approaches that may better solve the challenges associated with elastin based regenerative medicine.

ELN regulates cellular senescence: Emerging hypothesis for a non-canonical role

Elastic fibers are well-known extracellular matrix components that are essential for elastic properties and thus function of many tissues. Tropoelastin is encoded by the ELN gene which is the main component of the elastic fibers. Elastic fibers decrease with aging and this decrease is proposed to contribute to this process. Senescent cells, cells that stop to proliferate and that instruct their microenvironment, accumulate with aging and promote it. Until recently, whether ELN expression and function is linked to cellular senescence was unknown. Here we will comment and extend recent results supporting a function of the ELN gene in protecting cells from cellular senescence. We will also discuss hypotheses on mechanisms by which ELN could regulate cellular senescence, and especially a hypothesis that involves a non-canonical function of ELN regulating the mitochondrial respiratory chain activity, thereby controlling oxidative stress and cellular senescence. These findings provide critical insights into the molecular and cellular processes potentially underlying the phenotypes driven by ELN deletion in the context of aging.

Expression of Elastin, F-Box and WD-40 Domain-Containing Protein 2, Fibrillin-1, and Alpha-Smooth Muscle Actin in Utilized Blood Vessels for explant culture-A New 3D in Vitro Vascular Model from Bovine Legs

Elastic fibers of the internal and external elastic laminae maintain blood vessel shapes. Impairment of smooth muscle cell function leads to vascular disease development. F-box and WD-40 domain-containing protein 2 (FBXW2) is associated with elastic fibers and osteocalcin expression for bone regeneration in the periosteum. Here, it is hypothesized that FBXW2 has different roles in periosteum and blood vessels. Furthermore, if FBXW2 would be a component of elastic fiber of blood vessels, FBXW2 would be expressed where the well-known components elastin and fibrillin-1 are expressed. For this purpose, explant culture of blood vessels from bovine legs were performed for 5 weeks. It was found that elastin and FBXW2 were expressed within the elastic laminae, whereas fibrillin-1 was expressed around them. After explant culture, elastin and FBXW2 sustained the shape of the elastic fibers in the elastic lamina, whereas the fibrillin-1-rich layer became wide range and encompass toward intima and adventitia layers. Hematoxylin Eosin staining and immunohistochemistry of alpha-smooth muscle actin (α-SMA) revealed weakened media layer after 5 weeks culture. Although fibrillin-1 is a well-known component of elastic fibers and elastin, this study revealed that the location of fibrillin-1 is different from that of elastin, whereas FBXW2 is present in the same region as elastin from day 0 to week 5. In blood vessels, fibrillin-1 fibers around the elastic lamina may be oxytalan fibers. Thus, the proposed 3D in vitro model in this study is useful for identifying the mechanisms of vascular degradation.

Preparation, fractionation, and characterization of solubilized elastin and comparison of cellular response on fibroblasts and macrophages

Elastin and elastin-derived compounds are promising biomaterials due to their biological activity, unique natural crosslinks, and ability to mimic native tissue properties. Solubilized elastin peptides retain the bioactivity of elastin and are more suitable for wound care applications than the insoluble form. Chemically solubilized elastins have shown advantageous effects in skin regeneration in humans. Here, five solubilized elastins were prepared via chemical (stepwise and continuously hydrolyzed with oxalic acid - OxA-st-ELN and OxA-ELN, or with potassium hydroxide - KOH-ELN), enzymatic (Enz-ELN), or combined (Combi-ELN) methods. OxA-st-ELN had the largest molecular weights (MWs) fragments, while Enz-ELN and Combi-ELN yielded the smallest. The effects of elastin preparations were evaluated on primary human cells - dermal fibroblasts and macrophages. In fibroblast assays, Enz-ELN induced elastin, collagen, and fibrillin-2 protein deposition, while other preparations exhibited levels comparable to the control. α-smooth muscle actin (SMA) expression remained low across all conditions. Continuous oxalic acid hydrolysis simplified the traditional stepwise approach while maintaining bioactivity. Macrophage studies showed chemical hydrolysates preserved the M0-like subtype, while Enz-ELN promoted a pro-inflammatory M1-like phenotype, and Combi-ELN had mixed effects. OxA-ELN and KOH-ELN appeared to be the most promising options for developing biomaterial dermal scaffolds that support tissue regeneration in vivo.

Elastin dose-controlled mineral deposition by masking collagen-binding sites for calcium ions

Bone and blood vessel mineralization are representative of physiological and pathological mineralization, respectively. Collagen and elastin play important roles in regulating mineralization. Minerals are more readily deposited on elastin than on collagen. However, this observation is not consistent with the physiologic state of bone and blood vessels. Therefore, the present study investigated the effects of collagen and elastin on mineral deposition in the context of the structural composition of bone and blood vessels. The results indicated that the dose of elastin to collagen has a dual effect on mineral deposition. Elastin could regulate the binding sites of calcium ions on collagen when the proportional dosage to collagen was adjusted, thereby controlling mineral adsorption and inducing the development of mineralized collagen with controllable mineralization, structure, and mechanical properties. This study highlighted the critical role of the extracellular matrix in mineralization. In addition, elastin and collagen are common biomaterials used in the scaffolds and grafts for blood vessels and bone. An investigation of the mechanical properties and the degree of mineralization of collagen and elastin after mixing can provide novel insights for designing biomaterials and preventing secondary injuries caused by implantation.

Extracellular Matrix Reorganization During Endometrial Decidualization

Extracellular matrix reorganization, a concurrent process of endometrial decidualization, has garnered widespread recognition. However, our understanding of this process remains limited. In this study, we aimed to investigate the expression, spatial distribution, and reorganization of fibrillar collagens, elastin, and lysyl oxidases within the decidua. Using second harmonic generation imaging, we successfully recorded fibrillar collagen reorganization between preimplantation and decidualized endometrium. Upon embryo implantation, the fibrillar collagens align themselves parallel to the direction of embryo invasion. Furthermore, we employed confocal imaging analysis to reveal distinct expression and spatial distribution patterns of elastin and lysyl oxidase-like enzymes. Elastin expression begins to manifest surrounding the implanting embryo, extends into the decidua, and exhibits a high concentration in the mesometrial region after gestation day 8. All lysyl oxidase-like enzymes are localized within the decidua, although they exhibit varying expression patterns. To gain further insights, we utilized an in vitro stromal cell decidualization model and provided compelling evidence that stromal cells serve as the primary source of the extracellular matrix components during endometrial decidualization. Additionally, we demonstrated that the genes encoding factors involved in the synthesis, processing, and assembly of fibrillar collagen and elastic fibers exhibit differential expression patterns during in vitro decidualization. Genes such as asporin, decorin, thrombospondin 2, fibulin 2, fibulin 5, and lysyl oxidase show significant induction during in vitro decidualization. In summary, our comprehensive analysis provides a detailed evaluation of the expression, spatial distribution, and reorganization of fibrillar collagens, elastin, and lysyl oxidases during the process of endometrial decidualization.

Effect of the SGLT2 inhibitor ipragliflozin on the expression of genes that regulate skin function

AIMS

Skin disorders occur more frequently with sodium-dependent glucose cotransporter type 2 (SGLT2) inhibitors than with other antidiabetic drugs. We conducted basic research using ipragliflozin, with the aim of identifying new measures to prevent skin disorders caused by SGLT2 inhibitors.

METHODS

db/db type 2 diabetes model mice were orally administered ipragliflozin (10 mg/kg or 30 mg/kg) once a day for 28 days and skin function genes were analysed by real-time RT-PCR or Western blotting.

RESULTS

No difference in the expression level of collagen (Col1a1 and Col1a2) in the skin was detected between the ipragliflozin treatment group and the control group. On the other hand, the expression levels of enzymes involved in the synthesis and decomposition of hyaluronic acid (Has2 and Hayl1) and enzymes involved in the synthesis and decomposition of ceramide (Sptlc1, Sptlc2, Asah1, and Acer1) were significantly decreased by the administration of ipragliflozin. Furthermore, the expression levels of filaggrin (Flg), loricrin (Lor), elastin (Eln), and aquaporin-3 (Aqp3) in the skin were lower in the ipragliflozin treatment group than in the control group.

CONCLUSIONS

It was revealed that ipragliflozin reduces the expression of genes involved in skin barrier and moisturizing functions, which this may be one of the mechanisms through which this drug causes skin disorders.

Control of Epithelial Tissue Organization by mRNA Localization

mRNA localization to specific subcellular regions is common in mammalian cells but poorly understood in terms of its physiological roles1-6,7. This study demonstrates the functional importance of Net1 mRNA, which we find prominently localized at the dermal-epidermal junction (DEJ) in stratified squamous epithelia. Net1 mRNA accumulates at DEJ protrusion-like structures that interact with the basement membrane and connect to a mechanosensitive network of microfibrils. Disrupting Net1 mRNA localization in mouse epithelium alters DEJ morphology and keratinocyte-matrix connections, affecting tissue homeostasis. mRNA localization dictates Net1 protein distribution and its function as a RhoA GTPase exchange factor (GEF). Altered RhoA activity is in turn sufficient to alter the ultrastructure of the DEJ. This study provides a high-resolution in vivo view of mRNA targeting in a physiological context. It further demonstrates how the subcellular localization of a single mRNA can significantly influence mammalian epithelial tissue organization, thus revealing an unappreciated level of post-transcriptional regulation that controls tissue physiology.

CASIN exerts anti-aging effects through RPL4 on the skin of naturally aging mice

Skin aging has been associated with the onset of various skin issues, and recent studies have identified an increase in Cdc42 activity in naturally aging mice. While previous literature has suggested that CASIN, a specific inhibitor of Cdc42 activity, may possess anti-aging properties, its specific effects on the epidermis and dermis, as well as the underlying mechanisms in naturally aging mice, remain unclear. Our study revealed that CASIN demonstrated the ability to increase epidermal and dermal thickness, enhance dermal-epidermal junction, and stimulate collagen and elastic fiber synthesis in 9-, 15-, and 24-month-old C57BL/6 mice in vivo. Moreover, CASIN was found to enhance the proliferation, differentiation, and colony formation and restore the cytoskeletal morphology of primary keratinocytes in naturally aging skin in vitro. Furthermore, the anti-aging properties of CASIN on primary fibroblasts in aging mice were mediated by the ribosomal protein RPL4 using proteomic sequencing, influencing collagen synthesis and cytoskeletal morphology both in vitro and in vivo. Meanwhile, both subcutaneous injection and topical application exhibited anti-aging effects for a duration of 21 days. Additionally, CASIN exhibited anti-inflammatory properties, while reduced expression of RPL4 was associated with increased inflammation in the skin of naturally aging mice. Taken together, our results unveil a novel function of RPL4 in skin aging, providing a foundational basis for future investigations into ribosomal proteins. And CASIN shows promise as a potential anti-aging agent for naturally aging mouse skin, suggesting potential applications in the field.

Photoaging protective effect of enzyme extracted pomegranate peel against oxidative damage in UVB-irradiated HaCaT cells

In this study, the ultraviolet B (UVB)-induced skin photoaging inhibitory activity of pomegranate peel extract with increased ellagic acid content through enzymatic hydrolysis was evaluated in HaCaT cells. Among various enzymes, Viscozyme with high tannase and β-glucosidase activities was used, and 1.0 % Viscozyme was added to hydrolyze pomegranate peel for 2 h at 40°C to establish the optimal reaction conditions for high ellagic acid content. Subsequently, when cells were treated with enzyme extracted pomegranate peels (40 μg/mL), the gene expression of matrix metalloproteinases (MMP)-2 and 13, which play key role in skin elasticity and moisture, and the protein expression of MMP13 were downregulated compared to the UVB-control group (UVB-C). In addition, the protein expression levels of tissue inhibitors, metalloproteinase-1 and 2, and collagen type I alpha 1 were upregulated, the gene expression of hyaluronic acid synthase-1, and filaggrin significantly increased, and interleukin-1β increased by photoaging was decreased. Furthermore, compared to the UVB-C, there was a significant increase in the gene expression of superoxide dismutase-1 and glutathione peroxidase, which resulted in a decrease in reactive oxygen species and malondialdehyde levels. These results were confirmed to be due to the inhibition of the mitogen-activated protein kinase pathway and downregulation of the protein expression of phosphorylated extracellular signal-regulated kinase, c-Jun N-terminal kinase, and P38. In conclusion, pomegranate peel, from which ellagic acid was extracted using Viscozyme, showed a reactive oxygen species inhibitory effect in UVB-irradiated HaCaT cells and thus may have a significant potential as a cosmetic ingredient with anti-aging effects.

The elastic system: A review of elastin-related techniques and hematoxylin-eosin/phloxine applicability for normal and pathological tissue description

The elastic system is one of the most developed interstitial elements in connective tissue. With diverse functions, pre-elastic and elastic fibers contribute to the distensibility and malleability of several organs. Also, microanalyses of the elastic system were obtained by different histological techniques that were employed over years to describe normal and pathological conditions. Compared to conventional stains, hematoxylin-eosin/phloxine (HE/P) under fluorescence and confocal microscopy presented a highly detailed observation of the elastic system in different organs and scenarios. This technique provides a better demarcation of the elastic fibers, favoring their description in relation to their deposition and aggregation in different organs. Also, fibrils with low aggregation or loss of this characteristic are observed in an optimal view in the skin, heart valves, and large-caliber blood vessels. Degradation, fragmentation, and rupture were also well described by the HE/P technique. Several organs, such as the mammary gland, prostate, skin, aorta, and lung, could be described with precision under this technique. In association with non-linear microscopy, the results of the research presented in this paper improved and detailed characteristics of precise pathogenesis. Thus, the HE/P technique presented an interesting efficiency to demonstrate alterations and structures in which the elastic system showed a relevant role, and when compared to other techniques it demonstrated a similar or better result. In addition, it is expected that future studies can reveal more information about the elastin and interactions with specific dyes, thus allowing a greater understanding of the great efficiency of this technique.

Antiaging Properties of Kalanchoe blossfeldiana Ethanol Extract-Ex Vivo and In Vitro Studies

Species of the genus Kalanchoe have a long history of therapeutic use in ethnomedicine, linked to their remarkable medical properties. These species include Kalanchoe blossfeldiana succulents, which grow in tropical regions. Despite the great interest in this plant, there are no reports about its therapeutic effects on the skin. In this study, the antioxidant properties of K. blossfeldiana ethanol extracts and the skin permeation of a topical hydrogel containing the extract (HKB) were assessed. Additionally, the content of active compounds in the K. blossfeldiana extract was evaluated by UHPLC-MS and HPLC-UV. The extract was analyzed with three antioxidant assays: ABTS, DPPH, and FRAP. Furthermore, the antielastase and antihialuronidase properties of the tested extract were assessed. Ex vivo penetration studies were performed using the Franz diffusion cells. The estimation of the cytotoxicity of HKB was performed by using an MTT assay ((4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) on the human fibroblasts HFF-1. The results obtained show that the antioxidant properties of K. blossfeldiana extract were similar to those of ascorbic acid, while antielastase and antihialuronidase tests indicated the strong antiaging and anti-inflammatory activity of the extract (IC50 was 26.8 ± 0.13 and 77.31 ± 2.44 µg/mL, respectively). Moreover, active ingredients contained in K. blossfeldiana extract penetrated through the human skin and accumulated in it. The cytotoxicity test showed that HKB had no significant effect on human fibroblasts at a concentration up to 0.5%. In conclusion, the hydrogel containing the K. blossfeldiana extract can be considered as an interesting and new alternative to dermatologic and cosmetic preparations.

Research Progress of Fibroblasts in Human Diseases

Fibroblasts, which originate from embryonic mesenchymal cells, are the predominant cell type seen in loose connective tissue. As the main components of the internal environment that cells depend on for survival, fibroblasts play an essential role in tissue development, wound healing, and the maintenance of tissue homeostasis. Furthermore, fibroblasts are also involved in several pathological processes, such as fibrosis, cancers, and some inflammatory diseases. In this review, we analyze the latest research progress on fibroblasts, summarize the biological characteristics and physiological functions of fibroblasts, and delve into the role of fibroblasts in disease pathogenesis and explore treatment approaches for fibroblast-related diseases.

Alveolar Mucosa-Switching Technique for Augmentation of the Attached Immobile Mucosa

In cases with a highly positioned mucogingival junction, an apically positioned flap in combination with palatal-mucosa grafting is commonly performed to deepen the sulcus. However, we believe that immobilizing the mucosa is more important than merely deepening it; thus, we developed a simple method based on the characteristics of its components. Elastic fiber should be replaced by collagen fiber. An apically positioned flap is no longer required and mobile alveolar mucosa, including elastic fibers, is just excised. Palatal-mucosa graft, including collagen fibers, is then performed. Mobile mucosa is switched to immobile mucosa, and histological evaluation supports this change. At the recipient site, simple excision of the mobile mucosa without an apically positioned flap is innovative.

Initiation of Medial Calcification: Revisiting Calcium Ion Binding to Elastin

Pathological calcification of elastin, a key connective tissue protein in the medial layers of blood vessels, starts with the binding of calcium ions. This Mini-Review focuses on understanding how calcium ions interact with elastin to initiate calcification at a molecular level, and emphasizes water's critical role in mediating this interaction. In the past decade, great strides have been made in understanding and modeling ion-specific hydration and its effects on biomolecule interactions. However, these advances have been largely absent from our understanding of elastin calcification. Historically, charge-neutral backbone carbonyls and negatively charged carboxyl groups have been proposed as elastin's calcium binding sites. Recently, tropoelastin's only four carboxyl groups have been identified as binding sites from classical molecular dynamics (MD). While carboxyl groups have a much higher affinity for binding calcium ions than backbone carbonyls, conflicting evidence persists for both functional group's importance in elastin calcification. This can be attributed to the fact that divalent ions strongly polarize water, leading to a hydration shell that shields electrostatic forces. The hydration shell surrounding both a calcium ion and either of the proposed binding sites must be displaced to enable binding. Providing our own extended X-ray absorption fine structure (EXAFS) data and complementary simulations, we discuss the potential structures of calcium binding in elastin and review prior knowledge regarding the relative importance of the two proposed binding sites.

Clinical Care for Cardiovascular Disease in Patients With Williams-Beuren Syndrome

Williams-Beuren syndrome (WBS) is a congenital multisystem disorder affecting the cardiovascular, central nervous, and musculoskeletal systems. Cardiovascular abnormalities, which consist principally of vascular stenoses, occur in approximately 80% of people with WBS and are the predominant cause of early morbidity and mortality. Supravalvar aortic stenosis and peripheral pulmonary artery stenosis are the most common stenotic lesions in WBS, though other stenoses often occur, including stenoses of the coronary arteries. Approximately one-third of people with WBS undergo cardiovascular interventions. The risk of sudden cardiac death is markedly higher than the general population, with most events occurring in the periprocedural period. Because of the rarity of WBS and the often-complex nature of the cardiovascular abnormalities, most physicians, including cardiologists, have limited experience in caring for patients with WBS. Further, heretofore, clinical cardiovascular management guidelines based on international expert consensus have not been available. This state-of-the-art review provides a comprehensive synopsis of the cardiovascular abnormalities in WBS and presents clinical management guidelines based on the authors' expert consensus.

Elastogenesis in Focus: Navigating Elastic Fibers Synthesis for Advanced Dermal Biomaterial Formulation

Elastin, a fibrous extracellular matrix (ECM) protein, is the main component of elastic fibers that are involved in tissues' elasticity and resilience, enabling them to undergo reversible extensibility and to endure repetitive mechanical stress. After wounding, it is challenging to regenerate elastic fibers and biomaterials developed thus far have struggled to induce its biosynthesis. This review provides a comprehensive summary of elastic fibers synthesis at the cellular level and its implications for biomaterial formulation, with a particular focus on dermal substitutes. The review delves into the intricate process of elastogenesis by cells and investigates potential triggers for elastogenesis encompassing elastin-related compounds, ECM components, and other molecules for their potential role in inducing elastin formation. Understanding of the elastogenic processes is essential for developing biomaterials that trigger not only the synthesis of the elastin protein, but also the formation of a functional and branched elastic fiber network.

Metabolic syndrome-associated murine aortic wall stiffening is associated with premature elastic fibers aging

Type 2 diabetes (T2D) constitutes a major public health problem, and despite prevention efforts, this pandemic disease is one of the deadliest diseases in the world. In 2022, 6.7 million patients with T2D died prematurely from vascular complications. Indeed, diabetes increases the risk of myocardial infarction or stroke eightfold. The identification of the molecular factors involved in the occurrence of cardiovascular complications and their prevention are therefore major axes. Our hypothesis is that factors brought into play during physiological aging appear prematurely with diabetes progression. Our study focused on the aging of the extracellular matrix (ECM), a major element in the maintenance of vascular homeostasis. We characterized the morphological and functional aspects of aorta, with a focus on the collagen and elastic fibers of diabetic mice aged from 6 mo to nondiabetic mice aged 6 mo and 20 mo. The comparison with the two nondiabetic models (young and old) highlighted an exacerbated activity of proteases, which could explain a disturbance in the collagen accumulation and an excessive degradation of elastic fibers. Moreover, the generation of circulating elastin-derived peptides reflects premature aging of the ECM. These extracellular elements contribute to the appearance of vascular rigidity, often the origin of pathologies such as hypertension and atherosclerosis. In conclusion, we show that diabetic mice aged 6 mo present the same characteristics of ECM wear as those observed in mice aged 20 mo. This accelerated aortic wall remodeling could then explain the early onset of cardiovascular diseases and, therefore, the premature death of patients with T2D.NEW & NOTEWORTHY Aortic elastic fibers of young (6-mo old) individuals with diabetes degrade prematurely and exhibit an appearance like that found in aged (20-mo old) nondiabetic mice. Exacerbated elastolysis and elastin-derived peptide production are characteristic elements, contributing to early aortic wall rigidity and hypertension development. Therefore, limiting this early aging could be a judicious therapeutic approach to reduce cardiovascular complications and premature death in patients with diabetes.

Assessment of Extracellular Matrix Fibrous Elements in Male Dermal Aging: A Ten-Year Follow-Up Preliminary Case Study

Skin aging is a complex phenomenon influenced by multiple internal and external factors that can lead to significant changes in skin structure, particularly the degradation of key extracellular matrix (ECM) components such as collagen and elastic fibers in the dermis. In this study, we aimed to meticulously assess the morphological changes within these critical fibrous ECM elements in the dermis of the same volunteer at age 47 and 10 years later (2012 to 2022). Using advanced histological staining techniques, we examined the distribution and characteristics of ECM components, including type I collagen, type III collagen, and elastic fibers. Morphological analysis, facilitated by hematoxylin and eosin staining, allowed for an accurate assessment of fiber bundle thickness and a quantification of collagen and elastic fiber areas. In addition, we used the generalized Pareto distribution for histogram modeling to refine our statistical analyses. This research represents a pioneering effort to examine changes in ECM fiber material, specifically within the male dermis over a decade-long period. Our findings reveal substantial changes in the organization of type I collagen within the ECM, providing insight into the dynamic processes underlying skin aging.

Dynamic Responses of Human Skin and Fascia to an Innovative Stimulation Device-Shear Wave Stimulation

Exposure to mechanical stimuli such as pressure and stretching prompts the skin to undergo physiological adaptations to accommodate and distribute applied forces, a process known as mechanotransduction. Mechanotherapy, which leverages mechanotransduction, shows significant promise across various medical disciplines. Traditional methods, such as massage and compression therapy, effectively promote skin healing by utilizing this mechanism, although they require direct skin contact. This study introduces a novel contactless modality, Shear Wave Stimulation (SWS), and evaluates its efficacy compared to traditional massage in eliciting responses from human skin and fascia. Fifteen healthy volunteers received SWS, while another fifteen volunteers received massage. Tests of skin mechanical properties revealed significant enhancements in skin shear modulus for both methods, showing an increase of approximately 20%. Additionally, deformation analysis of ultrasound images showed distinct responses of the skin and fascia to the two stimuli. SWS induced extension in the dermis (∼18%), hypodermis (∼16%), and fascia (∼22%) along the X and Y axes. In contrast, massage compressed the skin layers, reducing the dermis by around 15% and the hypodermis by about 8%, while simultaneously stretching the superficial fascia by approximately 8%. The observed extension across the entire skin with SWS highlights its potential as a groundbreaking contactless approach for promoting skin healing. Furthermore, the differing responses in blood flow reaffirm the distinct stimulation modes of SWS and massage. These findings establish a foundation for future innovative skin therapy modalities.

The Role of Fibroblasts in Skin Homeostasis and Repair

Fibroblasts are typical mesenchymal cells widely distributed throughout the human body where they (1) synthesise and maintain the extracellular matrix, ensuring the structural role of soft connective tissues; (2) secrete cytokines and growth factors; (3) communicate with each other and with other cell types, acting as signalling source for stem cell niches; and (4) are involved in tissue remodelling, wound healing, fibrosis, and cancer. This review focuses on the developmental heterogeneity of dermal fibroblasts, on their ability to sense changes in biomechanical properties of the surrounding extracellular matrix, and on their role in aging, in skin repair, in pathologic conditions and in tumour development. Moreover, we describe the use of fibroblasts in different models (e.g., in vivo animal models and in vitro systems from 2D to 6D cultures) for tissue bioengineering and the informative potential of high-throughput assays for the study of fibroblasts under different disease contexts for personalized healthcare and regenerative medicine applications.

Differential Contributions of Fibroblast Subpopulations to Intercellular Communication in Eosinophilic Esophagitis

Fibroblast heterogeneity remains undefined in eosinophilic esophagitis (EoE), an allergic inflammatory disorder complicated by fibrosis. We utilized publicly available single-cell RNA sequencing data (GSE201153) of EoE esophageal biopsies to identify fibroblast sub-populations, related transcriptomes, disease status-specific pathways and cell-cell interactions. IL13-treated fibroblast cultures were used to model active disease. At least 2 fibroblast populations were identified, F_A and F_B. Several genes including ACTA2 were more enriched in F_A. F_B percentage was greater than F_A and epithelial-mesenchymal transition upregulated in F_B vs. F_A in active and remission EoE. Epithelial-mesenchymal transition was also upregulated in F_B in active vs. remission EoE and TNF-α signaling via NFKB was downregulated in F_A. IL-13 treatment upregulated ECM-related genes more profoundly in ACTA2- fibroblasts than ACTA2+ myofibroblasts. After proliferating epithelial cells, F_B and F_A contributed most to cell-cell communication networks. ECM-Receptor interaction strength was stronger than secreted or cell-cell contact signaling in active vs. remission EoE and significant ligand-receptor pairs were driven mostly by F_B. This unbiased analysis identifies at least 2 fibroblast sub-populations in EoE in vivo, distinguished in part by ACTA2. Fibroblasts play a critical role in cell-cell interactions in EoE, most profoundly via ECM-receptor signaling via the F_B sub-group.

Directed Assembly of Elastic Fibers via Coacervate Droplet Deposition on Electrospun Templates

Elastic fibers provide critical elasticity to the arteries, lungs, and other organs. Elastic fiber assembly is a process where soluble tropoelastin is coacervated into liquid droplets, cross-linked, and deposited onto and into microfibrils. While much progress has been made in understanding the biology of this process, questions remain regarding the timing of interactions during assembly. Furthermore, it is unclear to what extent fibrous templates are needed to guide coacervate droplets into the correct architecture. The organization and shaping of coacervate droplets onto a fiber template have never been previously modeled or employed as a strategy for shaping elastin fiber materials. Using an in vitro system consisting of elastin-like polypeptides (ELPs), genipin cross-linker, electrospun polylactic-co-glycolic acid (PLGA) fibers, and tannic acid surface coatings for fibers, we explored ELP coacervation, cross-linking, and deposition onto fiber templates. We demonstrate that integration of coacervate droplets into a fibrous template is primarily influenced by two factors: (1) the balance of coacervation and cross-linking and (2) the surface energy of the fiber templates. The success of this integration affects the mechanical properties of the final fiber network. Our resulting membrane materials exhibit highly tunable morphologies and a range of elastic moduli (0.8-1.6 MPa) comparable to native elastic fibers.

Chirality Transfer of Glycopeptide across Scales Defined by the Continuity of Hydrogen Bonds

In nature, chirality transfer refines biomolecules across all size scales, bestowing them with a myriad of sophisticated functions. Despite recent advances in replicating chirality transfer with biotic or abiotic building blocks, a molecular understanding of the underlying mechanism of chirality transfer remains a daunting challenge. In this paper, the coassembly of two types of glycopeptide molecules differing in capability of forming intermolecular hydrogen bonds enabled the involvement of discontinuous hydrogen bond, which allowed for a nanoscale chirality transfer from glycopeptide molecules to chiral micelles, yet inhibited the micrometer scale chirality transfer toward helix formation, leading to an achiral transfer from chiral micelles to planar monolayer. Upon stacking the monolayer into a bilayer, the nonsuperimposable front and back faces of the chiral micelles involved in the monolayer ribbons lead to the opposite rotation of two layers toward increasing the continuity of H-bonds. The resultant continuity triggered the symmetry breaking of stacked bilayers and thus reactivated the micrometer-scale chirality transfer toward the final helix. This work delineates a promising step toward a better understanding and replicating the naturally occurring chirality transfer events and will be instructive to future chiral material design.

Expert Consensus on Big Data Collection of Skin and Appendage Disease Phenotypes in Chinese

The collection of big data on skin and appendage phenotypes has revolutionized the field of personalized diagnosis and treatment by enabling the evaluation of individual characteristics and early detection of abnormalities. To establish a standardized system for collecting and measuring big data on phenotypes, a systematic categorization of measurement entries has been undertaken, accompanied by recommendations on measurement entries, environmental equipment requirements, and collection processes, tailored to the needs of different usage scenarios. Specific collection sites have also been recommended based on different index characteristics. A multi-center, multi-regional collaboration has been initiated to collect big date on phenotypes of healthy and diseased skin in the Chinese population. This data will be correlated with patient disease information, exploring the factors influencing skin phenotype, analyzing the phenotypic data features that can predict prognosis, and ultimately promoting the exploration of the pathophysiology and pathogenesis of skin diseases and therapeutic approaches. Non-invasive skin measurement robots are also in development. This consensus aims to provide a reference for the study of phenomics and the standardization of phenotypic measurements of skin and appendages in China.

Developing Plant Exosomes as an Advanced Delivery System for Cosmetic Peptide

Peptides are a promising skincare ingredient, but due to their inherent instability and the barrier function of the skin's surface, they often have limited skin absorption and penetration, which can significantly hinder their skincare benefits. To address this, a novel technique called NanoGlow has been introduced for encapsulating peptide-based cosmetic raw materials into engineered nanosized plant-derived exosomes (pExo) to achieve the goal of a healthier and more radiant skin state. In this approach, pExo served as carriers for cosmetic peptides across the intact skin barrier, enhancing their biological effectiveness in skin beauty. The NanoGlow strategy combines chemical activation and physical proencapsulation, boasting a high success rate and straightforward and stable operation, making it suitable for large-scale production. Comprehensive analysis using in vitro cellular absorption and skin penetration models has demonstrated that the nanosized pExo carriers significantly improve peptide penetration into the skin compared to free peptides. Furthermore, in vivo tissue slice studies have shown that pExo carriers efficiently deliver acetyl hexapeptide-8 to the skin's dermis, surpassing the performance of free peptides. Cosmetic skincare effect analysis has also indicated that pExo-loaded cosmetic peptides deliver superior results. Therefore, the NanoGlow technique harnesses the natural size and properties of pExo to maximize the bioavailability of cosmetic peptides, holding great promise for developing advanced peptide delivery systems in both the cosmetic and medical drug industries.

Sialic acids cleavage induced by elastin-derived peptides impairs the interaction between insulin and its receptor in adipocytes 3T3-L1

The insulin receptor (IR) plays an important role in insulin signal transduction, the defect of which is believed to be the root cause of type 2 diabetes. In 3T3-L1 adipocytes as in other cell types, the mature IR is a heterotetrameric cell surface glycoprotein composed of two α subunits and two β subunits. Our objective in our study, is to understand how the desialylation of N-glycan chains, induced by elastin-derived peptides, plays a major role in the function of the IR. Using the 3T3-L1 adipocyte line, we show that removal of the sialic acid from N-glycan chains (N893 and N908), induced by the elastin receptor complex (ERC) and elastin derived-peptides (EDPs), leads to a decrease in the autophosphorylation activity of the insulin receptor. We demonstrate by molecular dynamics approaches that the absence of sialic acids on one of these two sites is sufficient to generate local and general modifications of the structure of the IR. Biochemical approaches highlight a decrease in the interaction between insulin and its receptor when ERC sialidase activity is induced by EDPs. Therefore, desialylation by EDPs is synonymous with a decrease of IR sensitivity in adipocytes and could thus be a potential source of insulin resistance associated with diabetic conditions.

Contribution of the ELRs to the development of advanced in vitro models

Developing in vitro models that accurately mimic the microenvironment of biological structures or processes holds substantial promise for gaining insights into specific biological functions. In the field of tissue engineering and regenerative medicine, in vitro models able to capture the precise structural, topographical, and functional complexity of living tissues, prove to be valuable tools for comprehending disease mechanisms, assessing drug responses, and serving as alternatives or complements to animal testing. The choice of the right biomaterial and fabrication technique for the development of these in vitro models plays an important role in their functionality. In this sense, elastin-like recombinamers (ELRs) have emerged as an important tool for the fabrication of in vitro models overcoming the challenges encountered in natural and synthetic materials due to their intrinsic properties, such as phase transition behavior, tunable biological properties, viscoelasticity, and easy processability. In this review article, we will delve into the use of ELRs for molecular models of intrinsically disordered proteins (IDPs), as well as for the development of in vitro 3D models for regenerative medicine. The easy processability of the ELRs and their rational design has allowed their use for the development of spheroids and organoids, or bioinks for 3D bioprinting. Thus, incorporating ELRs into the toolkit of biomaterials used for the fabrication of in vitro models, represents a transformative step forward in improving the accuracy, efficiency, and functionality of these models, and opening up a wide range of possibilities in combination with advanced biofabrication techniques that remains to be explored.

Identifying SCC Lesions Capable of Spontaneous Regression by Using Immunohistochemistry: A Systematic Review and Meta-Analysis

INTRODUCTION

Keratoacanthoma (KA) and squamous cell carcinoma (SCC) are two cutaneous conditions with morphological resemblance, which can complicate the diagnosis in some cases. Using immunohistochemistry staining of biomarkers could be beneficial in resolving this obstacle.

OBJECTIVES

We investigated a variety of biomarkers assessed in different studies in order to find the most important and helpful biomarkers for differentiation between SCC and lesions capable of spontaneous regression.

METHODS

MEDLINE via PubMed and Google Scholar database were used to identify relevant literature up to 15 June 2022. The aim of our analyses was to determine the capability of biomarkers to distinguish between SCC and lesions capable of spontaneous regression using calculated individual and pooled odds ratios (OR) and 95% confidence intervals (CI) and I2 tests.

RESULTS

Six potential biomarkers were CD10 with pooled OR= 0.006 (95% CI: 0.001-0.057) and I2=0%; COX-2 with pooled OR=0.089 (95% CI: 0.029-0.269) and I2=17.1%; elastic fibers with pooled OR= 6.69 (95% CI: 2.928-15.281) and I2=0%; IMP-3 with pooled OR=0.145 (95% CI: 0.021-1.001) and I2=44.5%; P53 with pooled OR=0.371 (95% CI: 0.188-0.733) and I2=55.9%; AT1R with OR=0.026 (95% CI: 0.006-0.107).

CONCLUSIONS

We suggest the utilization of the following IHC biomarkers for discrimination between lesions with spontaneous regression such as KA and SCC: CD10, COX-2, and elastic fibers.

The Role of the NLRP3 Inflammasome in the Molecular and Biochemical Mechanisms of Cervical Ripening: A Comprehensive Review

The uterine cervix is one of the key factors involved in ensuring a proper track of gestation and labor. At the end of the gestational period, the cervix undergoes extensive changes, which can be summarized as a transformation from a non-favorable cervix to one that is soft and prone to dilation. During a process called cervical ripening, fundamental remodeling of the cervical extracellular matrix (ECM) occurs. The cervical ripening process is a derivative of many interlocking and mutually driving biochemical and molecular pathways under the strict control of mediators such as inflammatory cytokines, nitric oxide, prostaglandins, and reactive oxygen species. A thorough understanding of all these pathways and learning about possible triggering factors will allow us to develop new, better treatment algorithms and therapeutic goals that could protect women from both dysfunctional childbirth and premature birth. This review aims to present the possible role of the NLRP3 inflammasome in the cervical ripening process, emphasizing possible mechanisms of action and regulatory factors.

Structural and physical basis for the elasticity of elastin

Elastin function is to endow vertebrate tissues with elasticity so that they can adapt to local mechanical constraints. The hydrophobicity and insolubility of the mature elastin polymer have hampered studies of its molecular organisation and structure-elasticity relationships. Nevertheless, a growing number of studies from a broad range of disciplines have provided invaluable insights, and several structural models of elastin have been proposed. However, many questions remain regarding how the primary sequence of elastin (and the soluble precursor tropoelastin) governs the molecular structure, its organisation into a polymeric network, and the mechanical properties of the resulting material. The elasticity of elastin is known to be largely entropic in origin, a property that is understood to arise from both its disordered molecular structure and its hydrophobic character. Despite a high degree of hydrophobicity, elastin does not form compact, water-excluding domains and remains highly disordered. However, elastin contains both stable and labile secondary structure elements. Current models of elastin structure and function are drawn from data collected on tropoelastin and on elastin-like peptides (ELPs) but at the tissue level, elasticity is only achieved after polymerisation of the mature elastin. In tissues, the reticulation of tropoelastin chains in water defines the polymer elastin that bears elasticity. Similarly, ELPs require polymerisation to become elastic. There is considerable interest in elastin especially in the biomaterials and cosmetic fields where ELPs are widely used. This review aims to provide an up-to-date survey of/perspective on current knowledge about the interplay between elastin structure, solvation, and entropic elasticity.

Elastogenic potential and antisagging properties of a novel Murraya koenigii extract

BACKGROUND

The process by which functional elastic fibers are produced, namely elastogenesis, is complex and difficult to assess in vitro. Identifying efficient elasticity-boosting ingredients thus represents a challenge.

AIMS

The elasticity-boosting properties of a novel extract of Murraya koenigii leafy stems were assessed in vitro in 3D culture models before being evaluated in human female volunteers.

METHODS

Synthesis of elastic fiber related proteins was evaluated in a skin-equivalent model. Using multiphoton microscopy, the structural organization of elastin deposits was studied within a scaffold-free dermal microtissue. Biomechanical properties of the 3D microtissue were also measured by atomic force microscopy. In vivo, fringe-projection and image analysis were used to evaluate nasogenian fold severity in a panel of Caucasian female volunteers. The impact of gravity on visible signs of facial aging was assessed by clinical scoring carried out alternatively in the supine and sitting positions.

RESULTS

We showed the Murraya koenigii extract increased protein expressions of elastin and fibrillin-1 in a 3D skin equivalent model. Using scaffold-free dermal microtissue, we confirmed that Murraya koenigii extract allowed a proper and ordered network of elastin deposits and consequently improved tissue elasticity. Clinical data showed that a twice-daily application for 98 days of the extract formulated at 1% allowed to visibly reduce nasogenian fold severity, jowl severity and to mitigate the impact of gravity on the facial signs of aging.

CONCLUSION

The newly discovered extract of Murraya koenigii leafy stems represents an innovative antiaging ingredient suited for elasticity-boosting and antisagging claims.

Recent advances in production of sustainable and biodegradable polymers from agro-food waste: Applications in tissue engineering and regenerative medicines

Agro-food waste is a rich source of biopolymers such as cellulose, chitin, and starch, which have been shown to possess excellent biocompatibility, biodegradability, and low toxicity. These properties make biopolymers from agro-food waste for its application in tissue engineering and regenerative medicine. Thus, this review highlighted the properties, processing methods, and applications of biopolymers derived from various agro-food waste sources. We also highlight recent advances in the development of biopolymers from agro-food waste and their potential for future tissue engineering and regenerative medicine applications, including drug delivery, wound healing, tissue engineering, biodegradable packaging, excipients, dental applications, diagnostic tools, and medical implants. Additionally, it explores the challenges, prospects, and future directions in this rapidly evolving field. The review showed the evolution of production techniques for transforming agro-food waste into valuable biopolymers. However, these biopolymers serving as the cornerstone in scaffold development and drug delivery systems. With their role in wound dressings, cell encapsulation, and regenerative therapies, biopolymers promote efficient wound healing, cell transplantation, and diverse regenerative treatments. Biopolymers support various regenerative treatments, including cartilage and bone regeneration, nerve repair, and organ transplantation. Overall, this review concluded the potential of biopolymers from agro-food waste as a sustainable and cost-effective solution in tissue engineering and regenerative medicine, offering innovative solutions for medical treatments and promoting the advancement of these fields.

Anti-skin aging effect of sea buckthorn proanthocyanidins in D-galactose-induced aging mice

Oxidative stress in skin cells caused by changes in the external environment is one of the principal causes of skin aging. Sea buckthorn proanthocyanidins (SBPs) have good free radical scavenging ability. We established a senescence model by injecting 500 mg/kg D-galactose into the dorsal necks of mice, and then different doses of SBP (25, 50, and 100 mg/kg) were gavaged to explore the effects of SBP on the skin tissues of senescent mice and elucidate the related mechanism of action. The results reveal that SBP can alleviate the skin aging phenomenon caused by D-galactose-induced aging. It can also enhance the total antioxidant capacity in the body, thereby strengthening the body's antioxidant defense capability. In addition, SBP can effectively improve skin aging by regulating the TGF-β1/Smads pathway and MMPs/TIMP system, increasing the relative content of Col I and tropoelastin, further maintaining the stability of collagen fiber and elastic fiber structure. These results will provide the development and production of the antioxidant function of cosmetics and health products, providing a new train of thought.

The extracellular matrix glycoprotein fibrillin-1 in health and disease

Fibrillin-1 (FBN1) is a large, cysteine-rich, calcium binding extracellular matrix glycoprotein encoded by FBN1 gene. It serves as a structural component of microfibrils and provides force-bearing mechanical support in elastic and nonelastic connective tissue. As such, mutations in the FBN1 gene can cause a wide variety of genetic diseases such as Marfan syndrome, an autosomal dominant disorder characterized by ocular, skeletal and cardiovascular abnormalities. FBN1 also interacts with numerous microfibril-associated proteins, growth factors and cell membrane receptors, thereby mediating a wide range of biological processes such as cell survival, proliferation, migration and differentiation. Dysregulation of FBN1 is involved in the pathogenesis of many human diseases, such as cancers, cardiovascular disorders and kidney diseases. Paradoxically, both depletion and overexpression of FBN1 upregulate the bioavailability and signal transduction of TGF-β via distinct mechanisms in different settings. In this review, we summarize the structure and expression of FBN1 and present our current understanding of the functional role of FBN1 in various human diseases. This knowledge will allow to develop better strategies for therapeutic intervention of FBN1 related diseases.

Pulmonary fibroelastosis - A review

Elastin is a long-lived fibrous protein that is abundant in the extracellular matrix of the lung. Elastic fibers provide the lung the characteristic elasticity during inhalation with recoil during exhalation thereby ensuring efficient gas exchange. Excessive deposition of elastin and other extracellular matrix proteins reduces lung compliance by impairing ventilation and compromising gas exchange. Notably, the degree of elastosis is associated with the progressive decline in lung function and survival in patients with interstitial lung diseases. Currently there are no proven therapies which effectively reduce the elastin burden in the lung nor prevent dysregulated elastosis. This review describes elastin's role in the healthy lung, summarizes elastosis in pulmonary diseases, and evaluates the current understanding of elastin regulation and dysregulation with the goal of guiding future research efforts to develop novel and effective therapies.

Fabrication of Insoluble Elastin by Enzyme-Free Cross-Linking

Elastin is an essential extracellular matrix protein that enables tissues and organs such as arteries, lungs, and skin, which undergo continuous deformation, to stretch and recoil. Here, an approach to fabricating artificial elastin with close-to-native molecular and mechanical characteristics is described. Recombinantly produced tropoelastin are polymerized through coacervation and allysine-mediated cross-linking induced by pyrroloquinoline quinone (PQQ). A technique that allows the recovery and repeated use of PQQ for protein cross-linking by covalent attachment to magnetic Sepharose beads is developed. The produced material closely resembles natural elastin in its molecular, biochemical, and mechanical properties, enabled by the occurrence of the cross-linking amino acids desmosine, isodesmosine, and merodesmosine. It possesses elevated resistance against tryptic proteolysis, and its Young's modulus ranging between 1 and 2 MPa is similar to that of natural elastin. The approach described herein enables the engineering of mechanically resilient, elastin-like materials for biomedical applications.

Single-cell analysis of human dermal fibroblasts isolated from a single male donor over 35 years

The aim of this study is to examine the effects of ageing on dermal fibroblast heterogeneity based on samples obtained from the same donor. We used a dermal fibroblast lineage (named ASF-4 cell lines) isolated from the inner side of the upper arm of a healthy male donor over a 35-year period, beginning at 36 years of age. Because clonal analysis of ASF-4 cell lines demonstrated a donor age-dependent loss of proliferative capacity and acquisition of senescent traits at the single-cell level, cultured cells frozen at passage 10 at ages 36 and 72 years were subjected to single-cell RNA sequencing. Transcriptome analysis revealed an increase in senescent fibroblasts and downregulation of genes associated with extracellular matrix remodelling with ageing. In addition, two putative differentiation pathways, with one endpoint consisting of senescent fibroblasts and the other without, were speculated using a pseudo-time analysis. Knockdown of the characteristic gene of the non-senescent fibroblast cluster endpoint, EFEMP2, accelerated cellular senescence. This was also confirmed in two other normal human dermal fibroblast cell lines. The detection of a common cellular senescence-related gene from single-donor analysis is notable. This study provides new insights into the behaviour of dermal fibroblasts during skin ageing.

Genetic background determines severity of Loxl1-mediated systemic and ocular elastosis in mice

Pseudoexfoliation syndrome (PEX) is a systemic, age-related disorder characterized by elastosis and extracellular matrix deposits. Its most significant ocular manifestation is an aggressive form of glaucoma associated with variants in the gene encoding lysyl oxidase-like 1 (LOXL1). Depending upon the population, variants in LOXL1 can impart risk or protection for PEX, suggesting the importance of genetic context. As LOXL1 protein levels are lower and the degree of elastosis is higher in people with PEX, we studied Loxl1-deficient mice on three different genetic backgrounds: C57BL/6 (BL/6), 129S×C57BL/6 (50/50) and 129S. Early onset and high prevalence of spontaneous pelvic organ prolapse in BL/6 Loxl1-/- mice necessitated the study of mice that were <2 months old. Similar to pelvic organ prolapse, most elastosis endpoints were the most severe in BL/6 Loxl1-/- mice, including skin laxity, pulmonary tropoelastin accumulation, expansion of Schlemm's canal and dilation of intrascleral veins. Interestingly, intraocular pressure was elevated in 50/50 Loxl1-/- mice, depressed in BL/6 Loxl1-/- mice and unchanged in 129S Loxl1-/- mice compared to that of control littermates. Overall, the 129S background was protective against most elastosis phenotypes studied. Thus, repair of elastin-containing tissues is impacted by the abundance of LOXL1 and genetic context in young animals.

Lysyl Oxidases as Targets for Cancer Therapy and Diagnostic Imaging

The understanding of the contribution of the tumour microenvironment to cancer progression and metastasis, in particular the interplay between tumour cells, fibroblasts and the extracellular matrix has grown tremendously over the last years. Lysyl oxidases are increasingly recognised as key players in this context, in addition to their function as drivers of fibrotic diseases. These insights have considerably stimulated drug discovery efforts towards lysyl oxidases as targets over the last decade. This review article summarises the biochemical and structural properties of theses enzymes. Their involvement in tumour progression and metastasis is highlighted from a biochemical point of view, taking into consideration both the extracellular and intracellular action of lysyl oxidases. More recently reported inhibitor compounds are discussed with an emphasis on their discovery, structure-activity relationships and the results of their biological characterisation. Molecular probes developed for imaging of lysyl oxidase activity are reviewed from the perspective of their detection principles, performance and biomedical applications.

Improved tropoelastin synthesis in the skin by codon optimization and nucleotide modification of tropoelastin-encoding synthetic mRNA

Loss of elastin due to aging, disease, or injury can lead to impaired tissue function. In this study, de novo tropoelastin (TE) synthesis is investigated in vitro and in vivo using different TE-encoding synthetic mRNA variants after codon optimization and nucleotide modification. Codon optimization shows a strong effect on protein synthesis without affecting cell viability in vitro, whereas nucleotide modifications strongly modulate translation and reduce cell toxicity. Selected TE mRNA variants (3, 10, and 30 μg) are then analyzed in vivo in porcine skin after intradermal application. Administration of 30 μg of native TE mRNA with a me1 Ψ modification or 10 and 30 μg of unmodified codon-optimized TE mRNA is required to increase TE protein expression in vivo. In contrast, just 3 μg of a codon-optimized TE mRNA variant with the me1 Ψ modification is able to increase protein expression. Furthermore, skin toxicity is investigated in vitro by injecting 30 μg of mRNA of selected TE mRNA variants into a human full-thickness skin model, and no toxic effects are observed. Thereby, for the first time, an increased dermal TE synthesis by exogenous administration of synthetic mRNA is demonstrated in vivo. Codon optimization of a synthetic mRNA can significantly increase protein expression and therapeutic outcome.

Aging and Vascular Disease: A Multidisciplinary Overview

Vascular aging, i.e., the deterioration of the structure and function of the arteries over the life course, predicts cardiovascular events and mortality. Vascular degeneration can be recognized before becoming clinically symptomatic; therefore, its assessment allows the early identification of individuals at risk. This opens the possibility of minimizing disease progression. To review these issues, a search was completed using PubMed, MEDLINE, and Google Scholar from 2000 to date. As a network of clinicians and scientists involved in vascular medicine, we here describe the structural and functional age-dependent alterations of the arteries, the clinical tools for an early diagnosis of vascular aging, and the cellular and molecular events implicated. It emerges that more studies are necessary to identify the best strategy to quantify vascular aging, and to design proper physical activity programs, nutritional and pharmacological strategies, as well as social interventions to prevent, delay, and eventually revert the disease.

LC-MS/MS quantitation of elastin crosslinker desmosines and histological analysis of skin aging characteristics in mice

Elastic fibers consist of an insoluble inner core of elastin, which confers elasticity and resilience to vertebral organs and tissues. Desmosine (DES) and isodesmosine (IDES) are potential biomarkers of pathologies that lead to decreased elastin turnover. Mice are commonly used in research to mimic humans because of their similar genetics, physiology, and organ systems. The present study thus used senescent accelerated prone (SAMP10) and senescent accelerated resistant (SAMR1) mice to examine the connection between aging and histological or biomolecular changes. Mice were divided into three groups: SAMP10 fed a control diet (CD), SAMP10 fed a high-fat diet (HFD), and SAMR1 fed a CD. The percent liver to total body weight ratio (%LW/BW), desmosines (DESs or DES/IDES) content, and histological alterations in skin samples were evaluated. DESs were quantified using an isotope-dilution liquid chromatography-tandem mass spectrometry method with isodesmosine-¹³C₃,¹⁵N₁ as the internal standard (ISTD). The assays were repeatable, reproducible, and accurate, with %CV values ≤ (1.90, 1.77, and 3.03), ISTD area %RSD of (1.54, 0.92, and 1.13), and %AC of (99.02 ± 1.86, 101.00 ± 2.30, and 101.30 ± 2.90) for the calibrations (equimolar DES/IDES, DES, and IDES, respectively). The average DESs content per dry-weight abdominal skin and %LW/BW were similar between the three groups. Histological analyses revealed elastin fibers in five randomly selected samples. The epidermis and dermal white adipose tissue layers were thicker in SAMP10 mice than SAMR1 mice. Thus, characteristic signs of aging in SAMP10 and SAMR1 mice could not be differentiated based on measurement of DESs content of the skin or %LW/BW, but aging could be differentiated based on microscopic analysis of histological changes in the skin components of SAMP10 and SAMR1 mice.

Photoprotection and Antiaging Activity of Extracts from Honeybush (Cyclopia sp.)-In Vitro Wound Healing and Inhibition of the Skin Extracellular Matrix Enzymes: Tyrosinase, Collagenase, Elastase and Hyaluronidase

Cyclopia sp. (honeybush) is an African shrub known as a rich source of polyphenols. The biological effects of fermented honeybush extracts were investigated. The influence of honeybush extracts on extracellular matrix (ECM) enzymes responsible for the skin malfunction and aging process-collagenase, elastase, tyrosinase and hyaluronidase-was analysed. The research also included assessment of the in vitro photoprotection efficiency of honeybush extracts and their contribution to the wound healing process. Antioxidant properties of the prepared extracts were evaluated, and quantification of the main compounds in the extracts was achieved. The research showed that the analysed extracts had a significant ability to inhibit collagenase, tyrosinase and hyaluronidase and a weak influence on elastase activity. Tyrosinase was inhibited effectively by honeybush acetone (IC₅₀ 26.18 ± 1.45 µg/mL), ethanol (IC₅₀ 45.99 ± 0.76 µg/mL) and water (IC₅₀ 67.42 ± 1.75 µg/mL) extracts. Significant hyaluronidase inhibition was observed for ethanol, acetone and water extracts (IC₅₀ were 10.99 ± 1.56, 13.21 ± 0.39 and 14.62 ± 0.21µg/mL, respectively). Collagenase activity was inhibited effectively by honeybush acetone extract (IC₅₀ 42.5 ± 1.05 μg/mL). The wound healing properties of the honeybush extracts, estimated in vitro in human keratinocytes (HaCaTs), were indicated for water and ethanol extracts. In vitro sun protection factor (SPF in vitro) showed medium photoprotection potential for all the honeybush extracts. The quantity of polyphenolic compounds was estimated with the use of high-performance liquid chromatography equipped with diode-array detection (HPLC-DAD), indicating the highest mangiferin contents in ethanol, acetone and n-butanol extracts, while in the water extract hesperidin was the dominant compound. The antioxidant properties of the honeybush extracts were estimated with FRAP (2,4,6-Tris(2-pyridyl)-s-triazine) and DPPH (2,2-diphenyl-1-picrylhydrazyl) tests, indicating their strong antioxidant activity, similar to ascorbic acid for the acetone extract in both tests. The wound healing abilities, estimation of SPF in vitro and the direct influence on selected enzymes (elastase, tyrosinase, collagenase and hyaluronidase) of the tested honeybush extracts were analysed for the first time, indicating a high potential of these well-known herbal tea for antiaging, anti-inflammation, regeneration and protection of the skin.

Investigation on the Biological Safety and Activity of a Gluconolactone-Based Lotion for Dermocosmetic Application

(1) Background: Cosmeceuticals are formulas enriched with active ingredients that exert efficacy on different skin molecular targets. (2) Methods: Cell viability and the absence of potential irritant risk were evaluated on keratinocytes (HaCaT), fibroblasts (NHDF), adipocytes (3T3-L1), sebocytes (PCi-SEB_CAU) and reconstructed human epidermis (RHE), respectively. Several treatments were performed to evaluate the ability of the lotion to stimulate the production of collagen and elastin, stimulate the differentiation of keratinocytes and reduce the number of senescent cells following UVB stimulation. In addition, the modulation of genes involved in the production, storage and accumulation of sebum were investigated. (3) Results: The results obtained demonstrated the biosafety of the formula in all cell lines tested. The 24-h treatment with non-cytotoxic concentrations determined an increase in the expression of the collagen (COL1A1), elastin (ELN) and involucrin (IVL) genes, while a reduction of peroxisome proliferator-activated receptor-gamma (PPARγ) gene expression and a reduction of SA-βgal-positive cells were found. Moreover, the treatment did not interfere with normal steroid 5-alpha reductase (5RDA3) gene expression levels. (4) Conclusions: Data collected demonstrated the biosafety of the lotion, the non-comedogenic property and a multi targets anti-aging effect. In particular, data collected on the booster lotion make it a valid way to counteract the pore dilatation aging related.

Mechanical Properties and Functions of Elastin: An Overview

Human tissues must be elastic, much like other materials that work under continuous loads without losing functionality. The elasticity of tissues is provided by elastin, a unique protein of the extracellular matrix (ECM) of mammals. Its function is to endow soft tissues with low stiffness, high and fully reversible extensibility, and efficient elastic-energy storage. Depending on the mechanical functions, the amount and distribution of elastin-rich elastic fibers vary between and within tissues and organs. The article presents a concise overview of the mechanical properties of elastin and its role in the elasticity of soft tissues. Both the occurrence of elastin and the relationship between its spatial arrangement and mechanical functions in a given tissue or organ are overviewed. As elastin in tissues occurs only in the form of elastic fibers, the current state of knowledge about their mechanical characteristics, as well as certain aspects of degradation of these fibers and their mechanical performance, is presented. The overview also outlines the latest understanding of the molecular basis of unique physical characteristics of elastin and, in particular, the origin of the driving force of elastic recoil after stretching.

Synthesis of lysinonorleucine and mass spectrometric analysis of lysinonorleucine and merodesmosine in bovine ligament and eggshell membrane

Elastin is an important extracellular matrix protein that contributes to the elasticity of cells, tissues, and organs. Although crosslinking amino acids such as desmosine and isodesmosine have been identified in elastin, details regarding the structure remain unclear. In this study, an elastin crosslinker, lysinonorleucine, was chemically synthesized and detected in hydrolyzed bovine ligament and eggshell membrane samples utilizing tandem mass spectrometry. Merodesmosine, another crosslinker of elastin, was also measured in the same samples using the same analytical method. The resulting data should aid in the elucidating the crosslinking structure of elastin and eggshell membranes.

The Fabrication of Gelatin-Elastin-Nanocellulose Composite Bioscaffold as a Potential Acellular Skin Substitute

Gelatin usage in scaffold fabrication is limited due to its lack of enzymatic and thermal resistance, as well as its mechanical weakness. Hence, gelatin requires crosslinking and reinforcement with other materials. This study aimed to fabricate and characterise composite scaffolds composed of gelatin, elastin, and cellulose nanocrystals (CNC) and crosslinked with genipin. The scaffolds were fabricated using the freeze-drying method. The composite scaffolds were composed of different concentrations of CNC, whereas scaffolds made of pure gelatin and a gelatin-elastin mixture served as controls. The physicochemical and mechanical properties of the scaffolds, and their cellular biocompatibility with human dermal fibroblasts (HDF), were evaluated. The composite scaffolds demonstrated higher porosity and swelling capacity and improved enzymatic resistance compared to the controls. Although the group with 0.5% (w/v) CNC recorded the highest pore size homogeneity, the diameters of most of the pores in the composite scaffolds ranged from 100 to 200 μm, which is sufficient for cell migration. Tensile strength analysis revealed that increasing the CNC concentration reduced the scaffolds' stiffness. Chemical analyses revealed that despite chemical and structural alterations, both elastin and CNC were integrated into the gelatin scaffold. HDF cultured on the scaffolds expressed collagen type I and α-SMA proteins, indicating the scaffolds' biocompatibility with HDF. Overall, the addition of elastin and CNC improved the properties of gelatin-based scaffolds. The composite scaffolds are promising candidates for an acellular skin substitute.