Collagen fragmentation promotes oxidative stress and elevates matrix metalloproteinase-1 in fibroblasts in aged human skin

Age-related changes in the ratio of Type I/III collagen and fibril diameter in mouse skin

The content of type I collagen (COL-I) and type III collagen (COL-III) and the ratio between them not only affect the skin elasticity and mechanical strength, but also determine the fibril diameter. In this research, we investigated the age-related changes in COL-I/COL-III ratio with their formed fibril diameter. The experimental result was obtained from high performance liquid chromatography-mass spectrometer, hydroxyproline determination, picrosirius red staining and transmission electron microscopes (TEM), respectively. The result indicated that the COL-I/COL-III ratio in mouse skin increased with aging. From the 0th to 9th week, the COL-I/COLIII ratio increased from 1.3:1 to 4.5:1. From the 9th to the 18th week, it remained between 4.5:1 and 4.9:1. The total content of COL-I and COL-III firstly increased and then decreased with aging. The TEM result showed that the fibril diameter increased with aging. From the 0th to 9th week, the average fibril diameter increased from 40 to 112 nm; From the 9th to 18th weeks, it increased from 112 to 140 nm. After the 9th week. The fibril diameter showed obvious uneven distribution. Thus, the COL-I/COLIII ratio was proportional to the fibril diameter, but inversely proportional to the uniformity of fibril diameter.

Amentoflavone-Enriched Selaginella rossii Protects against Ultraviolet- and Oxidative Stress-Induced Aging in Skin Cells

Selaginellaceae plants are used in cosmetics to limit skin aging. This study is the first to investigate the anti-aging effects of Selaginella rossii (SR) on ultraviolet B (UVB)- and oxidative stress-induced skin cells. The 95% ethanol extract of Selaginella rossii (SR95E) contained much higher amounts of amentoflavone (AMF), an active compound, than other Selaginellaceae plants and was more effective in inhibiting matrix metalloproteinase (MMP)-1 expression in CCD-986sk fibroblasts. SR95E significantly decreased UVB-induced MMP-1, MMP-2, MMP-3 and MMP-9 expression and enhanced procollagen type I C-peptide content and mRNA expression of collagen type I alpha (COL1A)1 and COL1A2 in CCD-986sk fibroblasts. In HaCaT keratinocytes, SR95E treatment also dose-dependently decreased UVB-induced MMP-1 concentration and MMP-1, MMP-2, MMP-3 and MMP-9 mRNA expression. Moreover, SR95E treatment markedly inhibited UVB-induced c-Jun N-terminal kinase and p38 mitogen-activated protein kinase signaling and nuclear factor kappa-B signaling in HaCaT cells. Furthermore, SR95E and AMF markedly regulated the 2,2'-azobis(2-amidinopropane) dihydrochloride (AAPH)-induced expression of cellular senescence-related markers, including p16, p21 and LMNB1, in HaCaT cells. Overall, this study indicates that SR may have potential as a functional material on preventing UVB- and AAPH-induced skin aging and wrinkles.

Current Understanding of the Role of Senescent Melanocytes in Skin Ageing

Melanocytes reside within the basal epidermis of human skin, and function to protect the skin from ultraviolet light through the production of melanin. Prolonged exposure of the skin to UV light can induce irreparable DNA damage and drive cells into senescence, a sustained cell cycle arrest that prevents the propagation of this damage. Senescent cells can also be detrimental and contribute to skin ageing phenotypes through their senescence-associated secretory phenotype. Senescent cells can act in both an autocrine and paracrine manner to produce widespread tissue inflammation and skin ageing. Recently, melanocytes have been identified as the main senescent cell population within the epidermis and have been linked to a variety of skin ageing phenotypes, such as epidermal thinning and the presence of wrinkles. However, the literature surrounding melanocyte senescence is limited and tends to focus on the role of senescence in the prevention of melanoma. Therefore, this review aims to explore the current understanding of the contribution of senescent melanocytes to human skin ageing.

Protective role of Caesalpinia sappan extract and its main component brazilin against blue light-induced damage in human fibroblasts

BACKGROUND

Ultraviolet (UV) radiation is a well-known factor that causes skin aging. Recently, with the development of technology, the skin has been exposed to not only the UV radiation but also the blue light from electronic devices. Blue light is a high-energy visible light that penetrates deep into the dermal layer, producing reactive oxygen species (ROS) and resulting in skin aging. In this study, we searched for candidate materials that can inhibit blue light-induced skin aging and found Caesalpinia sappan extract (CSE) to be effective.

METHODS

Human dermal fibroblasts (HDFs) were treated with various concentrations of CSE and brazilin and exposed to blue light. We measured that antioxidant activity, MMP-1 levels using MMP-1 ELISA, changes in collagen type 1, collagen type 3, MMP-1, and MMP-3 mRNA expressions, and ROS generation.

RESULTS

We confirmed that CSE has high absorption of blue light and antioxidant activity. Blue light irradiation at 30 J/cm² decreased the expression of collagen types 1 and 3, increased the expression of matrix metalloproteinase (MMP)-1 and 3, and decreased the production of ROS in human dermal fibroblasts as compared to those of the nonirradiated group. However, pretreatment with CSE protected against the damage caused by the blue light. Brazilin, a major constituent of C. sappan, had high absorbance in the blue light region and antioxidant activities. Pretreatment with brazilin also inhibited the damage caused by the blue light in the cells.

CONCLUSION

CSE and brazilin are potential agents for inhibiting skin aging caused by blue light-induced damage.

Evaluation of Personalized Skincare Through in-silico Gene Interactive Networks and Cellular Responses to UVR and Oxidative Stress

Purpose

Personalized approaches in dermatology are designed to match the specific requirements based on the individual genetic makeup. One major factor accounting for the differences in skin phenotypes is single nucleotide polymorphism (SNP) within several genes with diverse roles that extend beyond skin tone and pigmentation. Therefore, the cellular sensitivities to the environmental stress and damage linked to extrinsic aging could also underlie the individual characteristics of the skin and dictate the unique skin care requirements. This study aimed to identify the likely biomarkers and molecular signatures expressed in skin cells of different ethnic backgrounds, which could aid further the design of personalized skin products based on specific demands.

Methods

Using data mining and in-silico modeling, the association of SNP-affected genes with three major skin types of European, Asian and African origin was analyzed and compared within the structure-function gene interaction networks. Cultured dermal fibroblasts were subsequently subjected to ultraviolet radiation and oxidative stress and analyzed for DNA damage and senescent markers. The protective applications of two cosmetic ingredients, Resveratrol and Quercetin, were validated in both cellular and in-silico models.

Results

Each skin type was characterized by the presence of SNPs in the genes controlling facultative and constitutive pigmentation, which could also underlie the major differences in responses to photodamage, such as oxidative stress, inflammation, and barrier homeostasis. Skin-type-specific dermal fibroblasts cultured in-vitro demonstrated distinctive sensitivities to ultraviolet radiation and oxidative stress, which could be modulated further by the bioactive compounds with the predicted capacities to interact with some of the genes in the in-silico models.

Conclusion

Evaluation of the SNP-affected gene networks and likely sensitivities of skin cells, defined as low threshold levels to extrinsic stress factors, can provide a valuable tool for the design and formulation of personalized skin products that match more accurately diverse ethnic backgrounds.

Anti-Aging Effect and Mechanism of Proanthocyanidins Extracted from Sea buckthorn on Hydrogen Peroxide-Induced Aging Human Skin Fibroblasts

Oxidative stress is the leading cause of skin aging damage. Excessive accumulation of reactive oxygen species (ROS) in cells induced by hydrogen peroxide (H₂O₂) triggers a decrease in collagen synthesis and an increase in collagen degradation, which are biomarkers of skin aging. We evaluated the potential protective mechanism of Sea buckthorn proanthocyanidins (SBP) against the oxidative stress-induced skin aging process from multiple aspects. We treated human skin fibroblasts (HSFs) with 300 µmoL/L of H₂O₂ for 24 h, followed by 25, 50, and 100 µg/mL of SBP for 24 h. The results showed that SBP could enhance the activities of superoxide dismutase (SOD) and glutathione (GSH), effectively remove excess ROS, and significantly improve the changes in cell morphology and viability caused by excessive ROS in skin cells. In addition, SBP could promote the synthesis of Col I in aging HSFs through the TGF-β1/Smads pathway and inhibit the degradation of Col I by regulating the MMPs/TIMPs system, thereby maintaining the stability of the ECM structure to achieve anti-aging purposes. Finally, we studied the migration ability of SBP, and the results showed that 100 µg/mL of SBP was most conducive to the cell migration of senescent cells, laying a foundation for follow-up animal experiments. These results will increase the application value of SBP in the cosmetic and antioxidative functional food industries.

Early stage ultraviolet irradiation damage to skin collagen can be suppressed by HPA axis control via controlled CYP11B

UV rays constitute an extremely important environmental factor known to operate adaptative mechanisms that maintain biological homeostasis in the skin, adrenal glands, and the brain. The skin is extremely vulnerable to UV rays. UV rays deform collagen, the main component of elastic fibers, decreasing its normal function, and ultimately reducing skin's elasticity. We confirmed that psychological stress occurring during the early stages of UVB-irradiation degraded collagen function by inhibiting production rather than the decomposition of collagen, thereby promoting skin aging. UV irradiation for 0-2 weeks increased the level of a stress factor, corticosterone (CORT). High-performance liquid chromatography and western blot analysis confirmed that the increase was caused by enhanced CYP11B1/2 levels during steroid synthesis in the adrenal gland. Precursor levels decreased significantly during the two weeks of UV irradiation. Skin collagen and collagen fibers reduced drastically during this time. Furthermore, the administration of osilodrostat, a USFDA-approved drug that selectively inhibits CYP11B1/2, preserved skin collagen. The mechanism underlying the reduction of CORT by osilodrostat confirmed that the amount of skin collagen could be preserved with treatment. In addition, upon suppression of the CORT receptor, the amount of collagen was controlled, and skin aging was suppressed by the hypothalamic-pituitary-adrenal axis. Therefore, this study confirmed an inverse relationship between adrenal CYP11B1/2 levels and collagen during the initial stages of UV irradiation of the skin. The findings of this study may be useful for developing new detection mechanisms for aging, following their further verification.

Expression of Polyamine Oxidase in Fibroblasts Induces MMP-1 and Decreases the Integrity of Extracellular Matrix

Polyamine oxidase (PAOX) (N¹-acetylpolyamine oxidase) is a major enzyme in the polyamine catabolism pathway that generates hydrogen peroxide. Hydrogen peroxide plays a crucial role in skin aging via extracellular matrix (ECM) degradation by increasing the matrix metalloproteinase-1 (MMP-1) levels. We analyzed the integrity of the ECM in foreskin fibroblasts using PAOX expression. PAOX increased the MMP-1 secretion and type Ι collagen degradation in 2D and 3D cultures of fibroblasts, respectively. Similarly, PAOX overexpression increased the messenger ribonucleic acid (mRNA) level of MMP-1. PAOX expression induced polyamine catabolism, decreased the spermine levels, and increased the putrescine levels. However, the exogenous polyamine treatment did not change the MMP-1 and type I collagen levels as much as PAOX expression. PAOX expression increased the reactive oxygen species (ROS) production in fibroblasts, and exogenous hydrogen peroxide increased both the ROS production and MMP-1 secretion. Furthermore, N-acetylcysteine, an antioxidant, reversed the PAOX-induced ROS production and MMP-1 secretion. PAOX induced the signaling pathways that activate activator protein-1 (AP-1) and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), which are important transcription factors for MMP-1 transactivation. We concluded that PAOX increased the ROS levels in fibroblasts, leading to an increase in MMP-1 expression. Therefore, we propose that PAOX is a potential target molecule in protecting the ECM integrity.

Changes in metabolic profiling of whiteleg shrimp (Penaeus vannamei) under hypoxic stress

Hypoxia is a common concern in shrimp aquaculture, affecting growth and survival. Although recent studies have revealed important insights into hypoxia in shrimp and crustaceans, knowledge gaps remain regarding this stressor at the molecular level. In the present study, a gas chromatography-mass spectrometry (GC-MS)-based metabolomics approach was employed to characterize the metabolic signatures and pathways underlying responses of Pacific white shrimp (Penaeus vannamei) to hypoxia and to identify associated candidate biomarkers. We compared metabolite profiles of shrimp haemolymph before (0 h) and after exposure to hypoxia (1 & 2 h). Dissolved oxygen levels were maintained above 85 % saturation in the control and before hypoxia, and 15 % saturation in the hypoxic stress treatment. Results showed 44 metabolites in shrimp haemolymph that were significantly different between before and after hypoxia exposure. These metabolites were energy-related metabolites (e.g., intermediates of citric acid cycle, lactic acid, alanine), fatty acids and amino acids. Pathway analysis revealed 17 pathways that were significantly affected by hypoxia. The changes in metabolites and pathways indicate a shift from aerobic to anaerobic metabolism, disturbance in amino acid metabolism, osmoregulation, oxidative damage and Warburg effect-like response caused by hypoxic stress. Among the altered metabolites, lactic acid was most different between before and after hypoxia exposure and had the highest accurate value for biomarker identification. Future investigations may validate this molecule as a stress biomarker in aquaculture. This study contributes to a better understanding of hypoxia in shrimp and crustaceans at the metabolic level and provides a base for future metabolomics investigations on hypoxia.

OLDER PATIENTS AND PATIENTS WITH SEVERE ARTERIOSCLEROSIS ARE LESS LIKELY TO DEVELOP KELOIDS AND HYPERTROPHIC SCARS AFTER THORACIC MIDLINE INCISION: A SURVEY-BASED ANALYSIS OF 328 CASES

BACKGROUND

Surgery is a well-known trigger of keloid and hypertrophic scarring. Sternotomy scars are subject to high skin tension, which is also known to promote pathological scarring. This suggests that sternotomies in adults associate with high pathological-scarring rates, which is also our anecdotal experience. However, this notion has never been formally examined. Therefore, we conducted a survey-based cohort study of patients who had undergone a sternotomy.

STUDY DESIGN

All consecutive Japanese adults (≥18 years) who underwent cardiovascular surgery with sternotomy in 2014-2017 were identified in 2019 by chart review and sent a questionnaire. Respondents formed the study cohort. The questionnaire presented randomly-ordered photos of representative mature, keloid, and hypertrophic scars and asked the patients to choose the image that best resembled their midline scar when it was particularly noticeable. The incidence of self-reported pathological scarring (keloids and hypertrophic scars were grouped together) and the patient demographic (age and sex) and clinical characteristics (e.g. intima media thickness of the left and right common and internal carotid arteries) that associated with pathological scarring were determined.

RESULTS

Of the 548 sternotomy patients, 328 (mean age, 67 years; 68.0% male) responded (60% response rate). Of these, 195 (59.5%) reported they had a pathological scar. Compared to mature-scar patients, pathological-scar patients had lower mean age (65 vs. 69 years, p=0.0002) and intima-media thickness (0.92 vs. 1.05 mm, p=0.028).

CONCLUSION

Sternotomy was associated with a high rate of pathological scarring. An older age and arteriosclerosis were associated with less pathological scarring.

Stimulatory effects of collagen production induced by coenzyme Q10 in cultured skin fibroblasts

Coenzyme Q₁₀ (CoQ₁₀) is a well-known antioxidant and serves as an essential carrier for electron transport and proton translocation in the mitochondrial respiratory chain. CoQ₁₀ has been widely commercially available in Japan as a dietary and health supple­ment since 2001 and it is used for the prevention of lifestyle-related diseases induced by aging. Recently, it was stated that for Japan, which is facing an aging society, CoQ₁₀ has been used in many skincare products. However, the physiological actions of CoQ₁₀ in skin fibroblasts are not fully understood. In this study, we examined the effect of CoQ₁₀ on cultured human skin fibroblast. In this study, CoQ₁₀ treatment increased intracellular CoQ₁₀ level and promoted proliferation of fibroblasts. In addition, CoQ₁₀ increased mRNA expression of type I, IV, VII collagen, elastin, and HSP47, whereas CoQ₁₀ has little effect on mRNA of type II and VIII MMP. These results suggested that CoQ₁₀ has the efficacy that it increases collagen production in skin, thereby there is possible of the anti-aging by CoQ₁₀ in Japan which reached an aging society, so that it might be based on new physiological function by CoQ₁₀.

Photoaging: UV radiation-induced inflammation and immunosuppression accelerate the aging process in the skin

Background

Excessive exposure of the skin to UV radiation (UVR) triggers a remodeling of the immune system and leads to the photoaging state which is reminiscent of chronological aging. Over 30 years ago, it was observed that UVR induced an immunosuppressive state which inhibited skin contact hypersensitivity.

Methods

Original and review articles encompassing inflammation and immunosuppression in the photoaging and chronological aging processes were examined from major databases including PubMed, Scopus, and Google Scholar.

Results

Currently it is known that UVR treatment can trigger a cellular senescence and inflammatory state in the skin. Chronic low-grade inflammation stimulates a counteracting immunosuppression involving an expansion of immunosuppressive cells, e.g., regulatory T cells (Treg), myeloid-derived suppressor cells (MDSC), and regulatory dendritic cells (DCreg). This increased immunosuppressive activity not only suppresses the function of effector immune cells, a state called immunosenescence, but it also induces bystander degeneration of neighboring cells. Interestingly, the chronological aging process also involves an accumulation of pro-inflammatory senescent cells and signs of chronic low-grade inflammation, called inflammaging. There is also clear evidence that inflammaging is associated with an increase in anti-inflammatory and immunosuppressive activities which promote immunosenescence.

Conclusion

It seems that photoaging and normal aging evoke similar processes driven by the remodeling of the immune system. However, it is likely that there are different molecular mechanisms inducing inflammation and immunosuppression in the accelerated photoaging and the chronological aging processes.

Collagen Mimetic Peptides Promote Adherence and Migration of ARPE-19 Cells While Reducing Inflammatory and Oxidative Stress

Epithelial cells of multiple types produce and interact with the extracellular matrix to maintain structural integrity and promote healthy function within diverse endogenous tissues. Collagen is a critical component of the matrix, and challenges to collagen’s stability in aging, disease, and injury influence survival of adherent epithelial cells. The retinal pigment epithelium (RPE) is important for maintaining proper function of the light-sensitive photoreceptors in the neural retina, in part through synergy with the collagen-rich Bruch’s membrane that promotes RPE adherence. Degradation of Bruch’s is associated with RPE degeneration, which is implicated early in age-related macular degeneration, a leading cause of irreversible vision loss worldwide. Collagen mimetic peptides (CMPs) effectively repair damage to collagen helices, which are present in all collagens. Our previous work indicates that in doing so, CMPs promote survival and integrity of affected cells and tissues in models of ocular injury and disease, including wounding of corneal epithelial cells. Here, we show that CMPs increase adherence and migration of the ARPE-19 line of human RPE cells challenged by digestion of their collagen substrate. Application of CMPs also reduced both ARPE-19 secretion of pro-inflammatory cytokines (interleukins 6 and 8) and production of reactive oxygen species. Taken together, these results suggest that repairing collagen damaged by aging or other pathogenic processes in the posterior eye could improve RPE adherence and survival and, in doing so, reduce the inflammatory and oxidative stress that perpetuates the cycle of destruction at the root of age-related diseases of the outer retina.

Extracellular Vesicles in Facial Aesthetics: A Review

Facial aesthetics involve the application of non-invasive or minimally invasive techniques to improve facial appearance. Currently, extracellular vesicles (EVs) are attracting much interest as nanocarriers in facial aesthetics due to their lipid bilayer membrane, nanosized dimensions, biological origin, intercellular communication ability, and capability to modulate the molecular activities of recipient cells that play important roles in skin rejuvenation. Therefore, EVs have been suggested to have therapeutic potential in improving skin conditions, and these highlighted the potential to develop EV-based cosmetic products. This review summarizes EVs’ latest research, reporting applications in facial aesthetics, including scar removal, facial rejuvenation, anti-aging, and anti-pigmentation. This review also discussed the advanced delivery strategy of EVs, the therapeutic potential of plant EVs, and clinical studies using EVs to improve skin conditions. In summary, EV therapy reduces scarring, rejuvenates aging skin, and reduces pigmentation. These observations warrant the development of EV-based cosmetic products. However, more efforts are needed to establish a large-scale EV production platform that can consistently produce functional EVs and understand EVs’ underlying mechanism of action to improve their efficacy.

Molecular Mechanisms of Changes in Homeostasis of the Dermal Extracellular Matrix: Both Involutional and Mediated by Ultraviolet Radiation

Skin aging is a multi-factorial process that affects nearly every aspect of skin biology and function. With age, an impairment of structures, quality characteristics, and functions of the dermal extracellular matrix (ECM) occurs in the skin, which leads to disrupted functioning of dermal fibroblasts (DFs), the main cells supporting morphofunctional organization of the skin. The DF functioning directly depends on the state of the surrounding collagen matrix (CM). The intact collagen matrix ensures proper adhesion and mechanical tension in DFs, which allows these cells to maintain collagen homeostasis while ECM correctly regulates cellular processes. When the integrity of CM is destroyed, mechanotransduction is disrupted, which is accompanied by impairment of DF functioning and destruction of collagen homeostasis, thereby contributing to the progression of aging processes in skin tissues. This article considers in detail the processes of skin aging and associated changes in the skin layers, as well as the mechanisms of these processes at the molecular level.

Blood donation improves skin aging through the reduction of iron deposits and the increase of TGF-β1 in elderly skin

Skin aging is characterized by a wide range of physiological and structural changes, including wrinkling, dyschromia, and roughness, as well as the reduction of dermal thickness and collagen content. Here, we showed that blood donation increased dermal thickness and collagen content and decreased the number of senescent cells in old mice. Transcriptomic and metabolomic studies revealed blood donation significantly altered aging-related pathways in the skin of old mice. Molecular genes analysis indicated blood donation decreased the expression of genes associated with inflammation such as Fols1, Cox-2, and IL-1β, and increased the expression of collagen-associated genes including TGF-β1, TGF-β2, and Col3a1. The improvement of skin aging by blood donation was associated with the reduction of iron deposits and the increase of TGF-β1 in elderly skin. Our results suggested that appropriate blood donation could promote collagen re-synthesis and improve skin aging.

Epilobium angustifolium L. as a Potential Herbal Component of Topical Products for Skin Care and Treatment-A Review

Epilobium angustifolium L. (EA) has been used as a topical agent since ancient times. There has been an increasing interest in applying EA as a raw material used topically in recent years. However, in the literature, there are not many reports on the comprehensive application of this plant to skin care and treatment. EA contains many valuable secondary metabolites, which determine antioxidant, anti-inflammatory, anti-aging, and antiproliferative activity effects. One of the most important active compounds found in EA is oenothein B (OeB), which increases the level of ROS and protects cells from oxidative damage. OeB also influences wound healing and reduces inflammation by strongly inhibiting hyaluronidase enzymes and inhibiting COX-1 and COX-2 cyclooxygenases. Other compounds that play a key role in the context of application to the skin are flavonoids, which inhibit collagenase and hyaluronidase enzymes, showing anti-aging and anti-inflammatory properties. While terpenes in EA play an important role in fighting bacterial skin infections, causing, among other things cell membrane, permeability increase as well as the modification of the lipid profiles and the alteration of the adhesion of the pathogen to the animal cells. The available scientific information on the biological potential of natural compounds can be the basis for the wider use of EA in skin care and treatment. The aim of the article is to review the existing literature on the dermocosmetic use of E. angustifolium.

Anti-Glycation and Anti-Aging Properties of Resveratrol Derivatives in the in-vitro 3D Models of Human Skin

Purpose

Human skin undergoes modifications affecting its structural properties and barrier functions involved in protection against age-related damage. Glycation is a non-enzymatic reaction between macromolecules and sugars causing alterations to the elastic fibers and premature aging of the skin. Glycation can be prevented by a range of bioactive molecules; however, at present only a few of them are validated for inclusion in cosmetic products. There is also a demand for reproducible in-vitro assays demonstrating the anti-aging effect of compounds on the skin. This study aimed to define the potential targets for screening and validation of anti-glycation activity of novel cosmetic candidates from natural products and to provide a plausible mechanism for their anti-aging potential based on 3D skin models.

Methods

Dermal fibroblasts and 3D skin models were treated with glycation agent and topical applications of Resveratrol derivatives. The samples were analyzed for advanced glycation end products (AGEs) alongside an organization of elastic fibers and expression of proliferative, senescence, and oxidative stress markers by autofluorescence, immunocytochemistry and quantitative assays.

Results

Accumulation of AGEs in the 3D skin model is associated with reduced stratification of the epidermis and re-organization of the collagen in the upper, cell-dense layer of the dermis. Treatment of dermal fibroblasts with Resveratrol, OxyResveratrol, Piceatannol, and Triacetyl Resveratrol ameliorates the effects of glycation consistent with cellular aging. Subsequent topical application of the compounds in skin models results in a reduction in glycation-induced AGEs, an increase in collagen expression and a stratification of the epidermis.

Conclusion

Glycation could result in age-related alterations in the structural and cellular organizations of the superficial layers of the skin, which can be restored by Resveratrol derivatives, pointing to their promising capacities as bioactive ingredients in cosmetic products. Insight into the potential parameters affected by skin glycation could also serve as a reference for screening the bioactive molecules for cosmetic purposes.

SOD3 Suppresses the Expression of MMP-1 and Increases the Integrity of Extracellular Matrix in Fibroblasts

The superoxide dismutase (SOD) family functions as a reactive oxygen species (ROS)-scavenging system by converting superoxide anions into hydrogen peroxide in the cytosol (SOD1), mitochondria (SOD2), and extracellular matrix (SOD3). In this study, we examined the potential roles of SOD family members in skin aging. We found that SOD3 expression levels were significantly more reduced in the skin tissues of old mice and humans than in young counterparts, but SOD1 and SOD2 expression levels remained unchanged with aging. Accordingly, we analyzed the effects of SOD3 on intracellular ROS levels and the integrity of the extracellular matrix in fibroblasts. The treatment of foreskin fibroblasts with recombinant SOD3 reduced the intracellular ROS levels and secretion of MMP-1 while increasing the secretion of type I collagen. The effects of SOD3 were greater in fibroblasts treated with the TNF-α. SOD3 treatment also decreased the mRNA levels and promoter activity of MMP-1 while increasing the mRNA levels and promoter activities of COL1A1 and COL1A2. SOD3 treatment reduced the phosphorylation of NF-κB, p38 MAPK, ERK, and JNK, which are essential for MMP-1 transactivation. In a three-dimensional culture of fibroblasts, SOD3 decreased the amount of type I collagen fragments produced by MMP-1 and increased the amount of nascent type I procollagen. These results demonstrate that SOD3 reduces intracellular ROS levels, suppresses MMP-1 expression, and induces type I collagen expression in fibroblasts. Therefore, SOD3 may play a role in delaying or preventing skin aging.

Skin-Whitening and Antiwrinkle Proprieties of Maackia amurensis Methanolic Extract Lead Compounds

(1) Background: This study aimed to investigate the feasibility of using Maackia amurensis branch extract as a cosmetic ingredient with skin-whitening and antiwrinkle effects. (2) Methods: The skin-whitening effect of M. amurensis branch extract was confirmed by investigating α-melanocyte-stimulating hormone (α-MSH)-induced melanin synthesis and melanogenic protein expression in B16F1 cells. The antiwrinkle effect of M. amurensis branch extract was verified by assessing matrix metalloproteinase (MMP)-1 expression and soluble collagen content in CCD-986sk cells. The major compounds in M. amurensis branch extract were identified through isolation and characterization and confirmed by high-performance liquid chromatography analysis. (3) Results: M. amurensis branch extract significantly inhibited α-MSH-induced melanin synthesis by 49%, 42%, and 18% at 50, 37.5, and 25 μg/mL concentrations, respectively, compared with the negative control (NC). M. amurensis branch extract also significantly reduced the expression of the microphthalmia-associated transcription factor, tyrosinase-related protein (TRP)-1, TRP-2, and tyrosinase in B16F1 cells. Furthermore, M. amurensis branch extracts decreased ultraviolet A-induced MMP-1 expression and increased soluble collagen synthesis in CCD-986sk cells. In addition, the major compounds present in M. amurensis branch extract were found to be formononetin, genistein, trans-resveratrol, piceatannol, and tectoridin. (4) Conclusions: M. amurensis branch extract has skin-whitening and antiwrinkle properties. Therefore, it can be used as an ingredient in functional cosmetics with skin-whitening and antiwrinkle effects.

Theragra chalcogramma Hydrolysate, Rich in Gly-Leu-Pro-Ser-Tyr-Thr, Alleviates Photoaging via Modulating Deposition of Collagen Fibers and Restoration of Extracellular Components Matrix in SD Rats

Excessive exposure of the skin to ultraviolet irradiation induces skin photoaging, which seriously deteriorates the barrier functions of skin tissue, and even causes skin damages and diseases. Recently, dietary supplements from marine sources have been found to be useful in modulating skin functions and can be used to alleviate photoaging. Herein, the low-molecular-weight hydrolysates with a photoaging-protection effect were prepared by enzymatic hydrolysis from Theragra chalcogramma (TCH), and the potential mechanism were subsequently explored. The results revealed that TCH desirably improved the barrier functions of photoaged skin and stimulated the deposition of ECM components Col I, Hyp, and HA in the dermal layer. Histologically, TCH reduced the epidermal hyperplasia and restored the impaired architectures in a dose-dependent manner. Meanwhile, the activity of matrix metalloproteinase-1 (MMP-1) in photoaging skin was inhibited, and the expression levels of elastin and fibrillin-1 were elevated accordingly after TCH administration, and the significant improvements were observed at high-dose level (p < 0.05). Taken together, the efficacy of TCH against skin photoaging is highly associated with the regulation on ECM metabolism and the repairing of damaged mechanical structure.

The neuropeptide Substance P facilitates the transition from an inflammatory to proliferation phase associated responses in dermal fibroblasts

The wound healing process is a product of three successive and overlapping phases of inflammation, proliferation and remodeling. Considerable efforts have been invested in deconstructing the intercellular crosstalk that orchestrates tissue repair and we investigated the role of neuropeptides released from peripheral neurons upon injury in mediating these interactions. Amongst the most abundant of these neuropeptides secreted by nerves in the skin, is Substance P (SP). Given the role of dermal fibroblasts in coordinating multiple processes in the wound healing program, the effect of SP on human dermal fibroblasts of different ages was evaluated. The use of a substrate that recapitulates the mechanical properties of the in vivo tissue revealed novel effects of SP on dermal fibroblasts, including a block in inflammatory cytokine expression. Moreover, SP can promote expression of some extracellular matrix components and generates signals that regulate angiogenesis. Interestingly, the response of fibroblasts to SP was reduced concomitant with donor age. Altogether, SP acts to inhibit the inflammatory responses and promote proliferation associated responses in an age-dependent manner in dermal fibroblasts, suggesting a role as a molecular switch between the inflammatory and proliferative phases of the wound healing response.

Chemical Composition and Effect against Skin Alterations of Bioactive Extracts Obtained by the Hydrodistillation of Eucalyptus globulus Leaves

Eucalyptus globulus is planted extensively for pulp, paper and wood production. Although bioactive compounds obtained from its biomass are used as cosmetics ingredients, the skin effects were not yet fully explored. In order to fill this gap, this work aimed to study the protective effect against skin damage provided by the essential oil (EO) obtained from the hydrodistillation of Eucalyptus globulus leaves, and by an extract obtained from the hydrodistillation residual water (HRW). The major compound identified in the EO was 1,8-Cineole, and the phenolic acids in the HRW included gallic acid as the main phenolic constituent. Moreover, non-toxic EO and HRW concentrations were shown to have anti-aging skin effects in vitro, decreasing age-related senescence markers, namely β-galactosidase and matrix metalloproteinases activation, as well as collagen type 1 upregulation. In addition, EO and HRW were found to exhibit depigmenting effects by inhibiting tyrosinase and melanin production, along with potent anti-inflammatory properties. Furthermore, the absence of skin irritation and sensitization in cells exposed to EO and HRW revealed the safety of both extracts for topical use. Taken together, these results highlight the beneficial effects of extracts obtained from Eucalyptus globulus biomass for skin aesthetic and health purposes, which should be explored deeply for the prediction of future pharmaceutical and dermocosmetics industrial applications.

Shedding a New Light on Skin Aging, Iron- and Redox-Homeostasis and Emerging Natural Antioxidants

Reactive oxygen species (ROS) are necessary for normal cell signaling and the antimicrobial defense of the skin. However excess production of ROS can disrupt the cellular redox balance and overwhelm the cellular antioxidant (AO) capacity, leading to oxidative stress. In the skin, oxidative stress plays a key role in driving both extrinsic and intrinsic aging. Sunlight exposure has also been a major contributor to extrinsic photoaging of the skin as its oxidising components disrupt both redox- and iron-homeostasis, promoting oxidative damage to skin cells and tissue constituents. Upon oxidative insults, the interplay between excess accumulation of ROS and redox-active labile iron (LI) and its detrimental consequences to the skin are often overlooked. In this review we have revisited the oxidative mechanisms underlying skin damage and aging by focussing on the concerted action of ROS and redox-active LI in the initiation and progression of intrinsic and extrinsic skin aging processes. Based on these, we propose to redefine the selection criteria for skin antiaging and photoprotective ingredients to include natural antioxidants (AOs) exhibiting robust redox-balancing and/or iron-chelating properties. This would promote the concept of natural-based or bio-inspired bifunctional anti-aging and photoprotective ingredients for skincare and sunscreen formulations with both AO and iron-chelating properties.

Repression of the Antioxidant Pyrroloquinoline Quinone in Skin Aging Induced by Bmi-1 Deficiency

It is uncertain whether Bmi-1 deficiency could lead to skin aging by redox imbalance and DNA damage. In this study, we first confirmed that Bmi-1 had a relatively high expression level in the skin and Bmi-1 expression levels gradually decreased with age. Then, we studied the role of Bmi-1 in the skin using a Bmi-1^−/− mouse model. Bmi-1^−/− mice were supplemented with or without pyrroloquinoline quinone (PQQ) for 5 weeks, and their skin phenotypes were compared with Bmi1^−/− and wild-type littermates. Our results showed that Bmi-1^−/− mice displayed decreased vertical thickness of skin, sparse hair follicles, and thinner and more irregular collagen bundles. Mechanistically, increased oxidative stress with reducing antioxidant capacity and induced DNA damage occurred in Bmi-1^−/− mice. Subsequently, this would lead to reduced cell proliferation, increased cell senescence and matrix metalloproteinases (MMPs), and the degradation of fibroblast function and further reduce collagen synthesis. All pathological alterations in the skin of Bmi-1^−/− mice were alleviated by PQQ supplementation. These results demonstrated that Bmi-1 might play a key role in protection from skin aging by maintaining redox balance and inhibiting DNA damage response and will be a novel and potential target for preventing skin aging.

Age-related downregulation of CCN2 is regulated by cell size in a YAP/TAZ-dependent manner in human dermal fibroblasts: impact on dermal aging

CCN2, a member of the CCN family of matricellular proteins, is a key mediator and biomarker of tissue fibrosis. We previously reported that CCN2 is significantly reduced in aged human dermis, which contributes to dermal aging through the downregulation of collagen production, the major structural protein in the skin. In this study, we investigated the underlying mechanisms of the age-related downregulation of CCN2 in human skin dermal fibroblasts. Dermal fibroblasts isolation and laser-capture microdissection‒coupled RT-PCR from human skin confirmed that age-related reduction of CCN2 expression is regulated by epigenetics. Mechanistic investigation revealed that age-related reduction of CCN2 is regulated by impaired dermal fibroblast spreading/cell size, which is a prominent feature of aged dermal fibroblasts in vivo. Gain-of-function and loss-of-function analysis confirmed that age-related downregulation of CCN2 is regulated by YAP/TAZ in response to reduced cell size. We further confirmed that restoration of dermal fibroblast size rapidly reversed the downregulation of CCN2 in a YAP/TAZ-dependent manner. Finally, we confirmed that reduced YAP/TAZ nuclear staining is accompanied by loss of CCN2 in aged human skin in vivo. Our data reveal a mechanism by which age-related reduction in fibroblast spreading/size drives YAP/TAZ-dependent downregulation of CCN2 expression, which in turn contributes to loss of collagen in aged human skin.

Ageing, Age-Related Cardiovascular Risk and the Beneficial Role of Natural Components Intake

Ageing, in a natural way, leads to the gradual worsening of the functional capacity of all systems and, eventually, to death. This process is strongly associated with higher metabolic and oxidative stress, low-grade inflammation, accumulation of DNA mutations and increased levels of related damage. Detrimental changes that accumulate in body cells and tissues with time raise the vulnerability to environmental challenges and enhance the risk of major chronic diseases and mortality. There are several theses concerning the mechanisms of ageing: genetic, free radical telomerase, mitochondrial decline, metabolic damage, cellular senescence, neuroendocrine theory, Hay-flick limit and membrane theories, cellular death as well as the accumulation of toxic and non-toxic garbage. Moreover, ageing is associated with structural changes within the myocardium, cardiac conduction system, the endocardium as well as the vasculature. With time, the cardiac structures lose elasticity, and fibrotic changes occur in the heart valves. Ageing is also associated with a higher risk of atherosclerosis. The results of studies suggest that some natural compounds may slow down this process and protect against age-related diseases. Animal studies imply that some of them may prolong the lifespan; however, this trend is not so obvious in humans.

Attenuation of UV-induced skin photoaging in rats by walnut protein hydrolysates is linked to the modulation of MAPK/AP-1 and TGF-β/Smad signaling pathways

There is growing evidence that prevention of skin photoaging by oral administration of food-derived proteins hydrolysates is intricately linked to its alleviation against oxidative stress through modulation of the signaling pathway. Previously, walnut protein hydrolysates (WPHs) were prepared by enzymatic hydrolysis by our group and exhibited excellent anti-photoaging effect through regulation of extracellular matrix metabolism and the NF-κB signaling pathway. However, its response to oxidative stress and cascade mechanism remain unknown. In the present study, Sprague-Dawley rats were exposed periodically to UV irradiation and orally administered with WPHs to further examine the effects of WPHs on the redox state, MAPK/AP-1 and TGF-β/Smad signaling pathways, type I procollagen synthesis, and histopathological impairments in photoaging skin. Intervention with WPHs for 18 weeks significantly alleviated the photoaging morphology, enhanced the antioxidant components, and downregulated the phosphorylation levels of extracellular signal-regulated kinase (ERK) and C-Jun N-terminal kinase (JNK and p38 proteins) in photoaging tissues, while significant alterations on the gene expression levels of ERK, JNK and p38 were not observed. Meanwhile, WPHs significantly activated the TGF-β/Smad signaling pathway and type I procollagen production. Furthermore, histopathological analysis illustrated that WPHs predominately attenuated epidermal hyperplasia, reduced inflammatory filtration, and promoted the deposition of collagen fibers in photoaging skin. Altogether, the underlying mechanism of WPHs attenuating skin photoaging might lie in the synergistic modulation by increasing the antioxidant capacity, modulating the MAPK/AP-1/MMP-1 and TGF-β/Smad signaling pathways, stimulating the synthesis of type I procollagen, and restoring the impaired architecture structure. Our findings suggest that WPHs are promising agents for preventing skin photoaging.

Protective effects of coenzyme Q10 on cell damage induced by hydrogen peroxides in cultured skin fibroblasts

Cellular senescence is an intricate and multifactorial phenomenon, which is characterized by an irreversible cellular growth arrest, it is caused in response to irretrievably DNA damage, telomere shorting, activation of oncogene, and oxidative stress. Human diploid fibroblasts are a well-established experimental model for premature senescence-related studies, and exposure of fibroblasts to H₂O₂ is widely used as a SIPS model. Recently, it has been reported many studies of CoQ₁₀ as to anti-aging effects, however the effect of CoQ₁₀ on H₂O₂-induced SIPS model of human skin fibroblasts has not been understood. So that, we investigated that human skin fibroblasts were used to investigate the prevention effect of CoQ₁₀ against H₂O₂-induced SIPS model. We created SIPS model fibroblasts with treatment of 100 μM H₂O₂ for 2 h. In this study, CoQ₁₀ also increased cell viability and mRNA levels of type I, IV collagen and protein level of type I collagen. Moreover, it is shown that CoQ₁₀ suppressed oxidative stress, degradation of collagen by increasing MMP expression, and decreasing senescence-associated phenotypes (e.g. SA-βgal positive staining and SASP) for preventing skin aging via H₂O₂-induced SIPS model. These results suggested that CoQ₁₀ has possibility to be contributory for extension of healthy life expectancy in Japan.

Dietary supplementation with sulforaphane ameliorates skin aging through activation of the Keap1-Nrf2 pathway

Visible impairments in skin appearance, as well as a subtle decline in its functionality at the molecular level, are hallmarks of skin aging. Activation of the nuclear factor (erythroid-derived 2)-like 2 (Nrf2)-pathway, which is important in controlling inflammation and oxidative stress that occur during aging, can be triggered by sulforaphane (SFN), an isothiocyanate found in plants from the Brassicaceae family. This study aimed to assess the effects of SFN intake on age-related skin alterations. Male C57BL6 young (2 months) and old (21 months) mice were treated for 3 months with SFN diet (442.5 mg per kg) or control diet. The antioxidant capacities of the skin were increased in old SFN-treated animals as measured by mRNA levels of Nrf2 (P<.001) and its target genes NQO1 (P<.001) and HO1 (P<.01). Protein expression for Nrf2 was also increased in old SFN fed animals (P<.01), but not the protein expression of NQO1 or HO1. Additionally, ROS and MMP9 protein levels were significantly decreased (P<.05) in old SFN fed animals. Histopathological analysis confirmed that there was no difference in epidermal thickness in old, when compared to young, SFN treated animals, while the dermal layer thickness was lower in old vs. young, treated animals (P<.05). Moreover, collagen deposition was improved with SFN treatment in young (P<.05) and structurally significantly improved in the old mice (P<.001). SFN dietary supplementation therefore ameliorates skin aging through activation of the Nrf2-pathway.

Collagen Scaffolds Treated by Hydrogen Peroxide for Cell Cultivation

Collagen in the body is exposed to a range of influences, including free radicals, which can lead to a significant change in its structure. Modeling such an effect on collagen fibrils will allow one to get a native structure in vitro, which is important for modern tissue engineering. The aim of this work is to study the effect of free radicals on a solution of hydrogen peroxide with a concentration of 0.006–0.15% on the structure of collagen fibrils in vitro, and the response of cells to such treatment. SEM measurements show a decrease in the diameter of the collagen fibrils with an increase in the concentration of hydrogen peroxide. Such treatment also leads to an increase in the wetting angle of the collagen surface. Fourier transform infrared spectroscopy demonstrates a decrease in the signal with wave number 1084 cm⁻¹ due to the detachment of glucose and galactose linked to hydroxylysine, connected to the collagen molecule through the -C-O-C- group. During the first day of cultivating ASCs, MG-63, and A-431 cells, an increase in cell adhesion on collagen fibrils treated with H₂O₂ (0.015, 0.03%) was observed. Thus the effect of H₂O₂ on biologically relevant extracellular matrices for the formation of collagen scaffolds was shown.

Skin Aging, Cellular Senescence and Natural Polyphenols

The skin, being the barrier organ of the body, is constitutively exposed to various stimuli impacting its morphology and function. Senescent cells have been found to accumulate with age and may contribute to age-related skin changes and pathologies. Natural polyphenols exert many health benefits, including ameliorative effects on skin aging. By affecting molecular pathways of senescence, polyphenols are able to prevent or delay the senescence formation and, consequently, avoid or ameliorate aging and age-associated pathologies of the skin. This review aims to provide an overview of the current state of knowledge in skin aging and cellular senescence, and to summarize the recent in vitro studies related to the anti-senescent mechanisms of natural polyphenols carried out on keratinocytes, melanocytes and fibroblasts. Aged skin in the context of the COVID-19 pandemic will be also discussed.

Structural and Functional Changes and Possible Molecular Mechanisms in Aged Skin

Skin aging is a complex process influenced by intrinsic and extrinsic factors. Together, these factors affect the structure and function of the epidermis and dermis. Histologically, aging skin typically shows epidermal atrophy due to decreased cell numbers. The dermis of aged skin shows decreased numbers of mast cells and fibroblasts. Fibroblast senescence contributes to skin aging by secreting a senescence-associated secretory phenotype, which decreases proliferation by impairing the release of essential growth factors and enhancing degradation of the extracellular matrix through activation of matrix metalloproteinases (MMPs). Several molecular mechanisms affect skin aging including telomere shortening, oxidative stress and MMP, cytokines, autophagic control, microRNAs, and the microbiome. Accumulating evidence on the molecular mechanisms of skin aging has provided clinicians with a wide range of therapeutic targets for treating aging skin.

Structural characterization of a pure polysaccharide from Bletilla striata tubers and its protective effect against H2O2-induced injury fibroblast cells

The present study investigated the structural characteristics and its protective effect against H₂O₂-induced injury fibroblast cells of Bletilla striata tuber polysaccharide. The polysaccharides were gently extracted by water and recovered using the method of alcohol precipitation, and after further purification by DEAE-Sepharose Fast Flow gel column, a pure polysaccharide (pBSP) was finally obtained. The structural characterization of pBSP were investigated by using periodate oxidation studies, Smith-degradation, FT-IR spectroscopy, 1D and 2D NMR spectroscopy. The antioxidant effect of pBSP was evaluated by inhibiting the production of reactive oxygen species (ROS) in human fibroblast model cells induced by H₂O₂. It was firstly reported that pBSP was composed of d-glucose and D-mannose in a molar ratio of 1.00:1.34 with a molecular weight of 327.6 kDa. The repeating units of pBSP contained (1 → 4)-linked-β-D-Manp, (1 → 4)-linked-α-D-Glcp and (1 → 3)-linked-β-D-Manp, and there was no branched chain. pBSP exhibited no toxic effect on fibroblasts cells and could protect them against H₂O₂-induced injuries. After pretreatment with pBSP for 24 h, the content of ROS in fibroblasts decreased significantly. These results not only confirm the availability B. striata, but also indicate that pBSP have potential antioxidant capacity. Our observations can provide foundation for further development of pBSP-based cosmetics.

Decreased levels of endocytic collagen receptor Endo180 in dermal fibroblasts lead to decreased production of type I collagen and increased expression of matrix metalloproteinase-1

BACKGROUND

Endo180 is involved in collagen remodeling by incorporating extracellular degraded collagen. Ultraviolet irradiation of dermal fibroblasts reduces Endo180 expression, which affects collagen fiber remodeling. However, it is unclear whether the decrease in Endo180 is directly related to the decrease in type I collagen fibers during photoaging. We aimed to clarify the relationship between Endo180 reduction and the decrease in type I collagen fibers observed in photoaged dermis.

METHODS

Endo180 was reduced in normal human dermal fibroblasts using RNAi. Endo180 knockdown cells were inoculated into collagen gels. The influence of Endo180 knockdown was evaluated by measuring mRNA expression of collagen fiber remodeling-related factors and collagen gel contraction. The collagen state and oxidative stress in the collagen gels were also measured.

RESULTS

Endo180 knockdown cells, which were confirmed by gelatin uptake inhibition, showed upregulation of matrix metalloproteinase-1 and downregulation of type I collagen mRNA expression when cultured in collagen gels. The contractility of the collagen gel was reduced by Endo180 knockdown. The collagen state in the extracellular matrix of the collagen gels containing Endo180 knockdown fibroblasts showed increased amounts of 3/4 fragmented collagen and denatured collagen and decreased type I collagen synthesis. In addition, an increase in intracellular oxidative stress was observed.

CONCLUSIONS

This study confirmed that the decrease in Endo180 caused a failure in collagen fiber formation and a decrease in collagen production, reproducing the photoaging dermal structural changes. This suggests that the decrease in Endo180 may be involved in wrinkle formation, which is a characteristic of photoaged skin.

Cyanobacteria and microalgae bioactive compounds in skin-ageing: potential to restore extracellular matrix filling and overcome hyperpigmentation

As the largest organ in human body, skin acts as a physicochemical barrier, offering protection against harmful environmental stressors, such as chemicals, pathogens, temperature and radiation. Nonetheless, skins prominence goes further, with a significant psychosocial role in an increasingly ageing population. Prompted by consumers’ concern regarding skincare, cosmetic industry has been developing new formulas capable of lessening the most visible signs of ageing, including reduction in skin density and elasticity, wrinkling and hyperpigmentation. Allied to skincare is the rising importance set on natural products, sustainably obtained from less environmental impacting methods. Cyanobacteria and microalgae are adding importance in this field, given their ability to biosynthesize secondary metabolites with anti-ageing potential. In this review, we present an overview on the potential of cyanobacteria and microalgae compounds to overcome skin-ageing, essentially by exploring their effects on the metalloproteinases collagenase, elastase, gelatinase and hyaluronidase, and in other enzymes involved in the pigmentation process.

Linking Oxidative Stress and DNA Damage to Changes in the Expression of Extracellular Matrix Components

Cells are subjected to endogenous [e.g., reactive oxygen species (ROS), replication stress] and exogenous insults (e.g., UV light, ionizing radiation, and certain chemicals), which can affect the synthesis and/or stability of different macromolecules required for cell and tissue function. Oxidative stress, caused by excess ROS, and DNA damage, triggered in response to different sources, are countered and resolved by specific mechanisms, allowing the normal physiological equilibrium of cells and tissues to be restored. One process that is affected by oxidative stress and DNA damage is extracellular matrix (ECM) remodeling, which is a continuous and highly controlled mechanism that allows tissues to readjust in reaction to different challenges. The crosstalk between oxidative stress/DNA damage and ECM remodeling is not unidirectional. Quite on the contrary, mutations in ECM genes have a strong impact on tissue homeostasis and are characterized by increased oxidative stress and potentially also accumulation of DNA damage. In this review, we will discuss how oxidative stress and DNA damage affect the expression and deposition of ECM molecules and conversely how mutations in genes encoding ECM components trigger accumulation of oxidative stress and DNA damage. Both situations hamper the reestablishment of cell and tissue homeostasis, with negative impacts on tissue and organ function, which can be a driver for severe pathological conditions.

A multiscale four-layer finite element model to predict the effects of collagen fibers on skin behavior under tension

Human skin is a complex multilayered multiscale material that exhibits nonlinear and anisotropic mechanical behavior. It has been reported that its macroscopic behavior in terms of progression of wrinkles induced by aging is strongly dependent on its microscopic composition in terms of collagen fibers in the dermis layer. In the present work, a multiscale four-layer 2D finite element model of the skin was developed and implemented in Matlab code. The focus here was to investigate the effects of dermal collagen on the macroscopic mechanical behavior of the skin. The skin was modeled by a continuum model composed of four layers: the Stratum Corneum, the epidermis, the dermis, and the hypodermis. The geometry of the different layers of the skin was represented in a 2D model with their respective thicknesses and material properties taken from literature data. The macroscopic behavior of the dermis was modeled with a nonlinear multiscale approach based on a multiscale elastic model of collagen structure going from cross-linked molecules to the collagen fiber, combined with a Mori-Tanaka homogenization scheme. The model includes the nonlinear elasticity of the collagen fiber density, the fiber radius, the undulation, and the fiber orientation. An axial tension was applied incrementally to the lateral surfaces of the skin model. A parametric study was performed in order to investigate the effect of the collagen constituents on the macroscopic skin mechanical behavior in terms of the predicted macroscopic stress-strain curve of the skin. The results of the FE computations under uniaxial tension showed that the different layers undergo different strains, leading to a difference in the transversal deformation at the top surface. In addition, the parametric study revealed a strong correlation between macroscopic skin elasticity and its collagen structure.

Insights into antioxidant activities and anti-skin-aging potential of callus extract from Centella asiatica (L.)

Formation of oxidative stress in dermal fibroblasts plays crucial roles in aging processes of skin. The use of phytochemicals that can promote capacity of fibroblasts to combat oxidative stress is an attractive strategy to prevent skin aging and promote skin beauty. Centella asiatica has been used to treat multitude of diseases for centuries. Previous investigations demonstrated that extracts from C. asiatica have a broad range of beneficial activities through their antioxidant activity. Hence, the extract from this medicinal plant could be a great candidate for anti-skin-aging agent. Callus culture offers a powerful platform for sustainable, rapid and large-scale production of phytochemicals to serve extensive demands of pharmaceutical and cosmeceutical industries. Here, we demonstrated the application of callus culture of Centella asiatica to produce bioactive metabolites. The 50% ethanolic extract of callus culture has distinctive features of chemical compositions and biological profiles. Information from HPTLC-DPPH and HPLC analysis suggested that the callus extract comprises distinctive antioxidant compounds, compared with those isolated from authentic plant. Moreover, results from cell culture experiment demonstrated that callus extract possesses promising antioxidant and anti-skin-aging activities. Pre-treatment with callus extract attenuated H₂O₂-induced-cytotoxicity on human dermal fibroblasts. The results from RT-qPCR clearly suggested that the upregulation of cellular antioxidant enzymes appeared to be major contributor for the protective effects of callus extract against oxidative stress. Moreover, supplementation with callus extract inhibited induction of matrix metalloprotease-9 following H₂O₂ exposure, suggesting its potential anti-skin-aging activity. Our results demonstrate the potential utility of C. asiatica callus extract as anti-skin-aging agent in cosmeceutical preparations.

Potential of Naturally Derived Compounds in Telomerase and Telomere Modulation in Skin Senescence and Aging

Proper functioning of cells-their ability to divide, differentiate, and regenerate-is dictated by genomic stability. The main factors contributing to this stability are the telomeric ends that cap chromosomes. Telomere biology and telomerase activity have been of interest to scientists in various medical science fields for years, including the study of both cancer and of senescence and aging. All these processes are accompanied by telomere-length modulation. Maintaining the key levels of telomerase component (hTERT) expression and telomerase activity that provide optimal telomere length as well as some nontelomeric functions represents a promising step in advanced anti-aging strategies, especially in dermocosmetics. Some known naturally derived compounds contribute significantly to telomere and telomerase metabolism. However, before they can be safely used, it is necessary to assess their mechanisms of action and potential side effects. This paper focuses on the metabolic potential of natural compounds to modulate telomerase and telomere biology and thus prevent senescence and skin aging.

Herbal Extracts as Potential Antioxidant, Anti-Aging, Anti-Inflammatory, and Whitening Cosmeceutical Ingredients

The aim of this research was to investigate and compare the antioxidant, anti-tyrosinase, anti-aging, and anti-inflammatory activities of 16 herbal extracts for topical application in cosmetic/cosmeceutical products. Herbal plant materials were extracted by infusion in boiled water for 15 min. The total phenolic content and total flavonoid content of each extract were investigated by the Folin-Ciocalteu and aluminum chloride methods, respectively. Antioxidant activities were investigated using 2,2'-diphenyl-1-picrylhydrazyl and a ferric reducing antioxidant power assay. Anti-tyrosinase and anti-aging activities were investigated using an in vitro enzymatic-spectrophotometric method. Anti-inflammatory activities were investigated using an enzyme-linked immunosorbent assay. The findings show that the Stevia rebaudiana extract has the most significant levels of both phenols and flavonoids (p<0.05). The S. rebaudiana, Rosa damascene, and Phyllanthus emblica extracts possessed the most significant antioxidant activities (p<0.05) and a promising whitening effect with moderate anti-tyrosinase activities. Furthermore, the Echinacea purpurea extract possessed the most significant anti-collagenase (78.5±0.0 %), anti-elastase (69.0±1.4 %), and anti-hyaluronidase activity (64.2±0.3 %). The Morus alba extract possessed the most significant anti-inflammatory activity since it could inhibit the secretion of interleukin-6 and tumor necrosis factor-α (p<0.05). Therefore, these herbal extracts have promising skin benefits and have potential for use as active ingredients in cosmetic/cosmeceutical products.

MMP1 drives tumor progression in large cell carcinoma of the lung through fibroblast senescence

Large cell carcinoma (LCC) is a rare and aggressive lung cancer subtype with poor prognosis and no targeted therapies. Tumor-associated fibroblasts (TAFs) derived from LCC tumors exhibit premature senescence, and coculture of pulmonary fibroblasts with LCC cell lines selectively induces fibroblast senescence, which in turn drives LCC cell growth and invasion. Here we identify MMP1 as overexpressed specifically in LCC cell lines, and we show that expression of MMP1 by LCC cells is necessary for induction of fibroblast senescence and consequent tumor promotion in both cell culture and mouse models. We also show that MMP1, in combination with TGF-β1, is sufficient to induce fibroblast senescence and consequent LCC promotion. Furthermore, we implicate PAR-1 and oxidative stress in MMP1/TGF-β1-induced TAF senescence. Our results establish an entirely new role for MMP1 in cancer, and support a novel therapeutic strategy in LCC based on targeting senescent TAFs.

Effect of injectable equine collagen type I on metabolic activity and apoptosis of gingival fibroblasts

Collagen as a biomaterial is widely used for tissue regeneration due to various advantages including its biodegradation, biocompatibility, and low allergenicity. Along with aesthetic medicine development, collagen is also used in the injectable form as a tissue biostimulator. The area of our study was collagen's impact on fibroblast activity and apoptosis. The research showed that atelocollagen decreases metabolic activity of fibroblasts, but also showed an increasing number of living cells after 48 h and 72 h incubation under the influence of collagen.

A role for estrogen in skin ageing and dermal biomechanics

The skin is the body's primary defence against the external environment, preventing infection and desiccation. Therefore, alterations to skin homeostasis, for example with skin ageing, increase susceptibility to skin disease and injury. Skin biological ageing is uniquely influenced by a combination of intrinsic and extrinsic (primarily photoageing) factors, with differential effects on skin structure and function. Interestingly, skin architecture rapidly changes following the menopause, as a direct result of reduced circulating 17β-estradiol. The traditional clinical benefit of estrogens are supported by recent experimental data, where 17β-estradiol supplementation prevents age-related decline in the skin's structural and mechanical properties. However, the off-target effects of 17β-estradiol continue to challenge therapeutic application. Here we discuss how ageing alters the physiological and structural properties of the dermal extracellular matrix, and explore how estrogen receptor-targeted therapies may restore the mechanical defects associated with skin ageing.

Collagen in Wound Healing

Normal wound healing progresses through inflammatory, proliferative and remodeling phases in response to tissue injury. Collagen, a key component of the extracellular matrix, plays critical roles in the regulation of the phases of wound healing either in its native, fibrillar conformation or as soluble components in the wound milieu. Impairments in any of these phases stall the wound in a chronic, non-healing state that typically requires some form of intervention to guide the process back to completion. Key factors in the hostile environment of a chronic wound are persistent inflammation, increased destruction of ECM components caused by elevated metalloproteinases and other enzymes and improper activation of soluble mediators of the wound healing process. Collagen, being central in the regulation of several of these processes, has been utilized as an adjunct wound therapy to promote healing. In this work the significance of collagen in different biological processes relevant to wound healing are reviewed and a summary of the current literature on the use of collagen-based products in wound care is provided.

Antioxidant Properties of Plant-Derived Phenolic Compounds and Their Effect on Skin Fibroblast Cells

Plants are rich sources of a diverse range of chemicals, many of which have significant metabolic activity. One large group of secondary compounds are the phenolics, which act as inter alia potent reactive oxygen scavengers in cells, including fibroblasts. These common dermis residue cells play a crucial role in the production of extracellular matrix components, such as collagen, and maintaining the integrity of connective tissue. Chronic wounds or skin exposure to UV-irradiation disrupt fibroblast function by the generation of reactive oxygen species, which may damage cell components and modify various signaling pathways. The resulting imbalance may be reversed by the antioxidant activity of plant-derived phenolic compounds. This paper reviews the current state of knowledge on the impact of phenolics on fibroblast functionality under oxidative stress conditions. It examines a range of compounds in extracts from various species, as well as single specific plant-derived compounds. Phenolics are a good candidate for eliminating the causes of skin damage including wounds and aging and acting as skin care agents.

Cellular Senescence and Inflammaging in the Skin Microenvironment

Cellular senescence and aging result in a reduced ability to manage persistent types of inflammation. Thus, the chronic low-level inflammation associated with aging phenotype is called “inflammaging”. Inflammaging is not only related with age-associated chronic systemic diseases such as cardiovascular disease and diabetes, but also skin aging. As the largest organ of the body, skin is continuously exposed to external stressors such as UV radiation, air particulate matter, and human microbiome. In this review article, we present mechanisms for accumulation of senescence cells in different compartments of the skin based on cell types, and their association with skin resident immune cells to describe changes in cutaneous immunity during the aging process.

Protective Effect of Spirulina-Derived C-Phycocyanin against Ultraviolet B-Induced Damage in HaCaT Cells

Background and objectives: Reactive oxygen species (ROS) overwhelm the antioxidant defense system, induce oxidative stress, and increase matrix metalloproteinase (MMP) expression, resulting in skin aging. Thus, preventing ultraviolet B (UVB)-induced skin damage can attenuate skin aging. Spirulina (a biomass of cyanobacteria, also called blue-green algae) is comprised of prokaryotes, whereas microalgae are eukaryotes and are rich in phycocyanin, a powerful antioxidant. Materials and Methods: Here, we investigated the photoprotective effects of spirulina-derived C-phycocyanin (C-PC) against UVB radiation using keratinocytes (HaCaT cells). Results: UVB radiation increased MMP-1 and MMP-9 expression but decreased involucrin, filaggrin, and loricrin expression. C-PC showed no toxicity at concentrations of 5–80 μg/mL in terms of HaCaT cell viability. UVB-irradiated HaCaT cells had a 50.8% survival rate, which increased to 80.3% with C-PC treatment. MMP expression increased with UVB treatment, whereas MMP-1 and MMP-9 concentrations decreased with C-PC treatment. UVB reduced involucrin, filaggrin, and loricrin expression in HaCaT cells, but 80 μg/mL C-PC increased their expression by >25%. In the UVB radiation group, dichlorofluorescin diacetate fluorescence intensity in HaCaT cells increased by 81.6% compared with that in the control group, whereas ROS production was reduced by 51.2% and 55.1% upon treatment with 40 and 80 μg/mL C-PC, respectively. Conclusions: C-PC might reduce or prevent skin aging by reducing UVB irradiation-induced skin wrinkles and free radicals.

The dark side of daylight: photoaging and the tumor microenvironment in melanoma progression

Continued thinning of the atmospheric ozone, which protects the earth from damaging ultraviolet radiation (UVR), will result in elevated levels of UVR reaching the earth's surface, leading to a drastic increase in the incidence of skin cancer. In addition to promoting carcinogenesis in skin cells, UVR is a potent extrinsic driver of age-related changes in the skin known as "photoaging." We are in the preliminary stages of understanding of the role of intrinsic aging in melanoma, and the tumor-permissive effects of photoaging on the skin microenvironment remain largely unexplored. In this Review, we provide an overview of the impact of UVR on the skin microenvironment, addressing changes that converge or diverge with those observed in intrinsic aging. Intrinsic and extrinsic aging promote phenotypic changes to skin cell populations that alter fundamental processes such as melanogenesis, extracellular matrix deposition, inflammation, and immune response. Given the relevance of these processes in cancer, we discuss how photoaging might render the skin microenvironment permissive to melanoma progression.