Age dependent increase of elastase type protease activity in mouse skin. Effect of UV-irradiation

Elaeagnus umbellata Fruit Extract Protects Skin from Ultraviolet-Mediated Photoaging in Hairless Mice

Photoaging refers to the accumulation of skin damage which includes wrinkle formation, loss of elasticity, and epidermal thickening due to repeated ultraviolet (UV) irradiation. The present study investigated the protective effects of Elaeagnus umbellata fruit extract (Elaea) on UV-mediated photoaged skin of SKH1 hairless mice and compared the effects of Elaea with ascorbic acid. Although there was no difference in body weight between groups during experimental period, oral administration of 50-200 mg/kg Elaea once daily for 15 weeks significantly prevented an increase in skin weight, epithelial thickening of epidermis, and apoptosis caused by UV irradiation. Skin replica and histopathological analyses revealed that Elaea dose-dependently decreased wrinkle and microfold formation. In addition, Elaea administration restored UV-mediated reduction in type I collagen and hyaluronan through the inhibition of matrix metalloproteinases and p38 mitogen-activated protein kinase expression. Moreover, Elaea suppressed UV-dependent increases in superoxide anion production, fatty acid oxidation, and protein nitration by up-regulating antioxidant system. Furthermore, Elaea alleviated infiltration of inflammatory cells in UV-irradiated skin. The preventive effects of 100 mg/kg Elaea administration against UV-induced photoaging were similar to those by 100 mg/kg ascorbic acid. Collectively, the present study suggests that the E. umbellata fruit is a promising edible candidate to prevent skin photoaging.

Multi-omic analysis of mandibuloacral dysplasia type A patient iPSC-derived MSC senescence reveals miR-311 as a novel biomarker for MSC senescence

Mandibuloacral dysplasia type A (MADA) is a rare genetic progeroid syndrome associated with lamin A/C (LMNA) mutations. Pathogenic mutations of LMNA result in nuclear structural abnormalities, mesenchymal tissue damage and progeria phenotypes. However, it remains elusive how LMNA mutations cause mesenchymal-derived cell senescence and disease development. Here, we established an in vitro senescence model using induced pluripotent stem cell-derived mesenchymal stem cells (iMSCs) from MADA patients with homozygous LMNA p.R527C mutation. When expanded to passage 13 in vitro, R527C iMSCs exhibited marked senescence and attenuation of stemness potential, accompanied by immunophenotypic changes. Transcriptome and proteome analysis revealed that cell cycle, DNA replication, cell adhesion and inflammation might play important roles in senescence. In-depth evaluation of changes in extracellular vesicle (EV) derived iMSCs during senescence revealed that R527C iMSC-EVs could promote surrounding cell senescence by carrying pro-senescence microRNAs (miRNAs), including a novel miRNA called miR-311, which can serve as a new indicator for detecting chronic and acute mesenchymal stem cell (MSC) senescence and play a role in promoting senescence. Overall, this study advanced our understanding of the impact of LMNA mutations on MSC senescence and provided novel insights into MADA therapy as well as the link between chronic inflammation and aging development.

Focus on the Contribution of Oxidative Stress in Skin Aging

Skin aging is one of the most evident signs of human aging. Modification of the skin during the life span is characterized by fine lines and wrinkling, loss of elasticity and volume, laxity, rough-textured appearance, and pallor. In contrast, photoaged skin is associated with uneven pigmentation (age spot) and is markedly wrinkled. At the cellular and molecular level, it consists of multiple interconnected processes based on biochemical reactions, genetic programs, and occurrence of external stimulation. The principal cellular perturbation in the skin driving senescence is the alteration of oxidative balance. In chronological aging, reactive oxygen species (ROS) are produced mainly through cellular oxidative metabolism during adenosine triphosphate (ATP) generation from glucose and mitochondrial dysfunction, whereas in extrinsic aging, loss of redox equilibrium is caused by environmental factors, such as ultraviolet radiation, pollution, cigarette smoking, and inadequate nutrition. During the aging process, oxidative stress is attributed to both augmented ROS production and reduced levels of enzymatic and non-enzymatic protectors. Apart from the evident appearance of structural change, throughout aging, the skin gradually loses its natural functional characteristics and regenerative potential. With aging, the skin immune system also undergoes functional senescence manifested as a reduced ability to counteract infections and augmented frequency of autoimmune and neoplastic diseases. This review proposes an update on the role of oxidative stress in the appearance of the clinical manifestation of skin aging, as well as of the molecular mechanisms that underline this natural phenomenon sometimes accelerated by external factors.

A Mixture of Topical Forms of Polydeoxyribonucleotide, Vitamin C, and Niacinamide Attenuated Skin Pigmentation and Increased Skin Elasticity by Modulating Nuclear Factor Erythroid 2-like 2

It is well-known that increased oxidative stress caused by ultraviolet B (UV-B) radiation induces melanogenesis and activates metalloproteinases (MMPs), which degrade collagen and elastin fibers, leading to decreased skin elasticity. Various antioxidant agents, such as vitamin C and niacinamide, have been evaluated for use as treatments for photoaging or skin pigmentation. In this study, we evaluated the ability of a topical liquid formula of polydeoxyribonucleotide (PDRN), vitamin C, and niacinamide (PVN) delivered via a microneedling therapy system (MTS) to attenuate photoaging and pigmentation by increasing nuclear factor erythroid 2-like 2 (NRF2)/heme oxygenase-1 (HO-1) and decreasing MMP expression in a UV-B-radiated animal model. The effects of the PVN were compared with those of individual PDRN and hydroquinone (HQ) compounds. The expression of NRF2/HO-1 significantly increased in response to HQ, PDRN, and PVN in UV-B-radiated animal skin. The activity of nicotinamide adenine dinucleotide phosphate hydrogen oxidase decreased in response to HQ, PDRN, and PVN, and the superoxide dismutase activity increased. The expression of tumor protein p53 and microphthalmia-associated transcription factor and tyrosinase activity decreased in response to HQ, PDRN, and PVN, and this decrease was accompanied by decreased melanin content in the skin. The expression of nuclear factor kappa-light-chain enhancer of activated B cells and MMP2/3/9 decreased in response to HQ, PDRN, and PVN in UV-B-radiated skin. However, the expression of collagen type I α1 chain and the amount of collagen fibers that were evaluated by Masson's trichrome staining increased in response to HQ, PDRN, and PVN. The contents of elastin fibers, fibrillin 1/2 and fibulin 5 increased in response to HQ, PDRN, and PVN. In conclusion, PVN delivered via MTS led to decreased melanogenesis and destruction of collagen and elastin fibers by MMPs, and, thus, PVN decreased skin pigmentation and increased skin elasticity.

Antioxidative and Skin Protective Effects of Canarium subulatum Methanol Extract on Keratinocytes

Canarium subulatum is a traditional medical herb used in South Asia. Recently, the anti-inflammatory effects of C. subulatum methanol extract (Cs-ME) have been reported; however, the effect of Cs-ME on skin physiology has not yet been elucidated. Therefore, in this study, we evaluated the protective effect of Cs-ME on UV-induced skin aging and cell death as well as the reinforcing effect on the skin barrier. According to viable cell counting and MTT assays, Cs-ME significantly reduced UV-evoked HaCaT cell death. Cs-ME blocked reactive oxygen species (ROS) generation in UV-irradiated HaCaT cells and showed radical scavenging activity against DPPH and ABTS. In addition, H2O2-induced cell death was inhibited by Cs-ME, indicating that Cs-ME protects cells from UV-derived cell death through the suppression of ROS. PCR analysis revealed that Cs-ME diminished the expression of aging-related HYAL-1 and MMP-1 genes in UV-treated HaCaT cells. Elevated HYAL-1 and MMP-1 mRNA expression in H2O2-stimulated HaCaT cells was also decreased by Cs-ME, suggesting that Cs-ME exerts antiaging activity via the inhibition of ROS. Expression of skin barrier components including filaggrin and hyaluronic acid synthase-1 was increased by Cs-ME and was modulated by ERK/p38-AP-1 signaling. Collectively, our data show that Cs-ME has cytoprotective and antiaging activity based on antioxidant properties. Furthermore, Cs-ME exerts skin barrier protective ability by regulating the AP-1 signaling pathway. Therefore, Cs-ME has the potential for use as an ingredient in cosmetics to protect the skin from UV irradiation, prevent photoaging, and strengthen the skin barrier.

Screening of ninety herbal products of commercial interest as potential ingredients for phytocosmetics

Elastase and tyrosinase are important targets both for cosmetics and for dermatological disorders. In this work, ninety herbal products were tested as inhibitors of these two enzymes. Eleven extracts resulted strongly active. Four out of them (Camellia sinensis, Ginkgo biloba, Rhodiola rosea, Vitis vinifera) inhibited both enzymes, five (Glycyrrhiza glabra, Ribes nigrum, Rheum officinale, Salvia officinalis, Tilia platyphyllos) were active against tyrosinase only, and two (Ceterach officinarum and Cinnamomum zeylanicum) proved selectively active against elastase. The IC₅₀ ranged from 3.1 to 104.9 μg/mL and 19.3 to 164.3 μg/mL, against elastase and tyrosinase, respectively. The most active extracts resulted enriched in flavonoids (from 1.47 to 56.47 mg RE/g of extract) and phenolics (from 37.43 to 123.56 mg GAE/g of extract), indicating also an antioxidant potential. Finally, a positive correlation between enzymatic bioactivities and phenolic content was also established.

Using an UPLC/MS-based untargeted metabolomics approach for assessing the antioxidant capacity and anti-aging potential of selected herbs

Aging is an unavoidable fate that afflicts all life, during this process in mammals reactive oxygen species (ROS) are generated which stimulate tyrosinase, elastase and collagenase activities that actively participate in skin aging. Therefore, the maintenance of antioxidant homeostasis is an important anti-aging strategy for skin. Nature has excellent anti-aging remedies that act externally as well as internally to delay the visual signs of aging. In view of this fact, the present study investigates the in vitro anti-aging activity of five medicinal plants belonging to phenolic rich families namely Rosmarinus officinalis, Lavandula officinalis, Matricaria chamomilla, Camellia sinensis and Pelargonium graveolens. The selected plants are those most frequently used in the preparation of ethnomedicinal recipes for the prevention or treatment of aging. The inhibitory effects of the ethanolic and aqueous extracts of the five selected plants on the activity of tyrosinase, elastase, and collagenase enzymes were investigated. Furthermore, the chemical composition of the plants and the antioxidant capacity of their extracts were assessed. The results showed that R. officinalis had the highest total phenolics content which was correlated with its potent antioxidant and anti-aging activities. To pinpoint the active metabolites in the tested extracts, we evaluated the metabolite variations using ultra-performance liquid chromatography coupled with high resolution electrospray ionization-tandem mass spectrometry (UPLC-HR-ESI-MS/MS). Multivariate data analysis (MVDA) revealed that R. officinalis significantly accumulated metabolites from the aromatic diterpenoid, flavonoid and phenolic acid classes. These results indicate that rosemary can be used for further development of topical preparations with anti-aging properties.

Aging is an unavoidable fate that afflicts all life, during this process in mammals, reactive oxygen species (ROS) are generated which stimulate tyrosinase, elastase and collagenase activities that actively participate in skin aging.

Proteolysis and Oxidation of Therapeutic Proteins After Intradermal or Subcutaneous Administration

The intradermal (ID) and subcutaneous (SC) routes are commonly used for therapeutic proteins (TPs) and vaccines; however, the bioavailability of TPs is typically less than small molecule drugs given via the same routes. Proteolytic enzymes in the dermal, SC, and lymphatic tissues may be responsible for the loss of TPs. In addition, the TPs may be exposed to reactive oxygen species generated in the SC tissue and the lymphatic system in response to injection-related trauma and impurities within the formulation. The reactive oxygen species can oxidize TPs to alter their efficacy and immunogenicity potential. Mechanistic understandings of the dominant proteolysis and oxidative routes are useful in the drug discovery process, formulation development, and to assess the potential for immunogenicity and altered pharmacokinetics (PK). Furthermore, in vitro tools representing the ID or SC and lymphatic system can be used to evaluate the extent of proteolysis of the TPs after the injection and before systemic entry. The in vitro clearance data may be included in physiologically based pharmacokinetic models for improved PK predictions. In this review, we have summarized various physiological factors responsible for proteolysis and oxidation of TPs after ID and SC administration.

Polydeoxyribonucleotide Activates Mitochondrial Biogenesis but Reduces MMP-1 Activity and Melanin Biosynthesis in Cultured Skin Cells

The regulation of mitochondrial biogenesis, melanogenesis, and connective tissue proteins is critical for homeostasis and aging skin cells. We examined the biological effects of polydeoxyribonucleotide (PDRN) on mitochondrial biogenesis, melanogenesis, and connective tissue proteins in vitro. In a radical scavenging assay, PDRN showed antioxidant activities in a dose-dependent manner, and those activities can suppress cellular oxidative stress in skin cells. PDRN directly inhibited mushroom tyrosinase activity and cellular tyrosinase activity, thus significantly reducing the cellular melanin content in B16-F10 melanocytes. The mRNA and protein expressions of the microphthalmia-associated transcription factor (MITF), which is a key melanogenic gene transcription factor, were significantly downregulated by PDRN. Accordingly, tyrosinase-related protein 1, dopachrome tautomerase, and tyrosinase, which gene expressions were regulated by MITF, were significantly downregulated by PDRN. Mitotracker-probed mitochondria image analysis suggested that PDRN enhanced mitochondrial density in both murine melanoma cells and in human skin fibroblast cells. In addition, PDRN strongly suppressed in vitro elastase enzyme activity in a dose-dependent manner and inhibited matrix metalloproteinase-1 gene expression in human skin fibroblast cells. Collectively, these findings indicate that PDRN has multiple beneficial biological activities in skin cells: hypopigmentation, induction of mitochondrial biogenesis, and the inhibition of collective tissue proteins.

MicroRNA-300: A Transcellular Mediator in Exosome Regulates Melanoma Progression

Melanoma is a common and high-mortality skin cancer. Oxidative stress and DNA damage caused by ultraviolet light (UV) are major causative factors of melanoma formation. However, the specific molecular mechanism is still unclear. In this study, 218 dysregulated genes and 104 dysregulated miRNAs in response to UV were screened by analyzing sequencing datasets. Among them, 29 up-regulated miRNAs and 28 down-regulated miRNAs were involved in the melanoma pathway. As the only differential gene in the melanoma pathway, GADD45B severely affects the prognosis of melanoma patients. MiR-300 is the only differentially expressed miRNA that regulates GADD45B. In addition, compared to normal melanocytes, miR-300 was significantly down-regulated in melanoma cells (log FC = −1.63) and exosomes (log FC = −1.34). Among the transcription factors predicted to regulate miR-300, MYC, PPARG, and ZIC2 were significantly up-regulated in melanoma cells, and TP53, JUN, JUNB, FOS, and FOSB interacted with GADD45B. We attempted to reveal the pathogenesis of melanoma and screen new biomarkers by constructing a TF-mRNA-miRNA axis in turn to provide a view for further research.

Clinical efficacy of herbal extract cream on the skin hydration, elasticity, thickness, and dermis density for aged skin: A randomized controlled double-blind study

BACKGROUND

Traditional medicine herbal prescriptions used for the treatment of skin disease have been developed into cosmetics. Sang-Hyul-Yun-Boo-Em (SHYBE) is a mixed herbal formula prescribed for patients with yin or blood deficiency patterns of skin disease. A previous study reported that SHYBE exercises anti-allergic and anti-inflammatory effects. To date, no study has reported the efficacy of cosmetics containing the SHYBE extract.

AIMS

To observe the efficacy of SHYBE extract cream on hydration, elasticity, thickness, and dermis density in aged skin.

METHODS

This was a double-blind randomized placebo-controlled parallel-group trial. The trial consisted of an 8-week topical application of the test or placebo products with two visits at 4-week intervals. A total of 46 healthy Korean females, aged 40-59, were enrolled in this study. Objective skin assessments for hydration, elasticity, thickness and dermis density, self-assessment, and safety assessment were conducted.

RESULTS

Sang-Hyul-Yun-Boo-Em extract cream improved skin hydration, elasticity, and dermal density in Asian middle-aged females compared with placebo cream, which excluded SHYBE extract and contained other cosmetic materials.

CONCLUSIONS

Sang-Hyul-Yun-Boo-Em extract cream showed anti-aging properties in middle-aged women. It could be recommended for aging skin with dryness, and loss of elasticity and density.

NMR-Based Metabolomics Profiling for Radical Scavenging and Anti-Aging Properties of Selected Herbs

Herbs that are usually recognized as medicinal plants are well known for their therapeutic effects and are traditionally used to treat numerous diseases, including aging. This study aimed to evaluate the metabolite variations among six selected herbs namely Curcurma longa, Oenanthe javanica, Vitex negundo, Pluchea indica, Cosmos caudatus and Persicaria minus using proton nuclear magnetic resonance (¹H-NMR) coupled with multivariate data analysis (MVDA). The free radical scavenging activity of the extract was measured by 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2-azinobis(3-ethyl-benzothiazoline-6-sulfonic acid) (ABTS) and oxygen radical absorbance capacity (ORAC) assay. The anti-aging property was characterized by anti-elastase and anti-collagenase inhibitory activities. The results revealed that P. minus showed the highest radical scavenging activities and anti-aging properties. The partial least squares (PLS) biplot indicated the presence of potent metabolites in P. minus such as quercetin, quercetin-3-O-rhamnoside (quercitrin), myricetin derivatives, catechin, isorhamnetin, astragalin and apigenin. It can be concluded that P. minus can be considered as a potential source for an anti-aging ingredient and also a good free radical eradicator. Therefore, P. minus could be used in future development in anti-aging researches and medicinal ingredient preparations.

The Beneficial Regulation of Extracellular Matrix and Heat Shock Proteins, and the Inhibition of Cellular Oxidative Stress Effects and Inflammatory Cytokines by 1α, 25 dihydroxyvitaminD3 in Non-Irradiated and Ultraviolet Radiated Dermal Fibroblasts

Intrinsic skin aging and photoaging, from exposure to ultraviolet (UV) radiation, are associated with altered regulation of genes associated with the extracellular matrix (ECM) and inflammation, as well as cellular damage from oxidative stress. The regulatory properties of 1α, 25dihydroxyvitamin D3 (vitamin D) include endocrine, ECM regulation, cell differentiation, photoprotection, and anti-inflammation. The goal of this research was to identify the beneficial effects of vitamin D in preventing intrinsic skin aging and photoaging, through its direct effects as well as its effects on the ECM, associated heat shock proteins (HSP-47, and -70), cellular oxidative stress effects, and inflammatory cytokines [interleukin (IL)-1 and IL-8] in non-irradiated, UVA-radiated, UVB-radiated dermal fibroblasts. With regard to the ECM, vitamin D stimulated type I collagen and inhibited cellular elastase activity in non-irradiated fibroblasts; and stimulated type I collagen and HSP-47, and inhibited elastin expression and elastase activity in UVA-radiated dermal fibroblasts. With regard to cellular protection, vitamin D inhibited oxidative damage to DNA, RNA, and lipids in non-irradiated, UVA-radiated and UVB-radiated fibroblasts, and, in addition, increased cell viability of UVB-radiated cells. With regard to anti-inflammation, vitamin D inhibited expression of Il-1 and IL-8 in UVA-radiated fibroblasts, and stimulated HSP-70 in UVA-radiated and UVB-radiated fibroblasts. Overall, vitamin D is predominantly beneficial in preventing UVA-radiation induced photoaging through the differential regulation of the ECM, HSPs, and inflammatory cytokines, and protective effects on the cellular biomolecules. It is also beneficial in preventing UVB-radiation associated photoaging through the stimulation of cell viability and HSP-70, and the inhibition of cellular oxidative damage, and in preventing intrinsic aging through the stimulation of type I collagen and inhibition of cellular oxidative damage.

Scarless wound healing: From development to senescence

An essential element of tissue homeostasis is the response to injuries, cutaneous wound healing being the most studied example. In the adults, wound healing aims at quickly restoring the barrier function of the skin, leading however to scar, a dysfunctional fibrotic tissue. On the other hand, in fetuses a scarless tissue regeneration takes place. During ageing, the wound healing capacity declines; however, in the absence of comorbidities a higher quality in tissue repair is observed. Senescent cells have been found to accumulate in chronic unhealed wounds, but more recent reports indicate that their transient presence may be beneficial for tissue repair. In this review data on skin wound healing and scarring are presented, covering the whole spectrum from early embryonic development to adulthood, and furthermore until ageing of the organism.

Spatiotemporal Labeling of Melanocytes in Mice

Melanocytes are pigment producing cells in the skin that give rise to cutaneous malignant melanoma, which is a highly aggressive and the deadliest form of skin cancer. Studying melanocytes in vivo is often difficult due to their small proportion in the skin and the lack of specific cell surface markers. Several genetically-engineered mouse models (GEMMs) have been created to specifically label the melanocyte compartment. These models give both spatial and temporal control over the expression of a cellular ‘beacon’ that has an added benefit of inducible expression that can be activated on demand. Two powerful models that are discussed in this review include the melanocyte-specific, tetracycline-inducible green fluorescent protein expression system (iDct-GFP), and the fluorescent ubiquitination-based cell cycle indicator (FUCCI) model that allows for the monitoring of the cell-cycle. These two systems are powerful tools in studying melanocyte and melanoma biology. We discuss their current uses and how they could be employed to help answer unresolved questions in the fields of melanocyte and melanoma biology.

Studies on secondary metabolite profiling, anti-inflammatory potential, in vitro photoprotective and skin-aging related enzyme inhibitory activities of Malaxis acuminata, a threatened orchid of nutraceutical importance

Malaxis acuminata D. Don., a small, terrestrial orchid, is endemic to tropical Himalayas at an altitude of 1200-2000m asl. The dried pseudobulbs are important ingredients of century old ayurvedic drug 'Ashtavarga' and a polyherbal immune-booster nutraceutical 'Chyavanprash', known to restore vigour, vitality and youthfulness. Considering tremendous medicinal importance of this threatened orchid species, a detailed study was undertaken for the first time to address its antioxidant potential, secondary metabolite contents and biological activities against skin-aging related enzymes (anti-collagenase, anti-elastase, anti-tyrosinase and xanthine oxidase) and anti-inflammatory activity (5-lipoxygenase and hyaluronidase) in different plant parts of wild and in vitro-derived plants of M. acuminata. Methanolic leaf and stem extracts were further evaluated for in vitro photoprotective activity against UV-B and UV-A radiations. Furthermore, secondary metabolite profiling of various plant parts was carried out by Gas Chromatography Mass Spectrometry (GC-MS). A significantly higher antioxidant potential (DPPH, metal chelating and ABTS^•+) with a comparative higher yield of secondary metabolites was observed in in vitro-derived plantlets as compared to the wild plants. Among various solvent systems used, methanolic leaf and stem extracts showed promising inhibitory activity against major skin aging-related enzymes and anti-inflammatory potential. Methanolic leaf and stem extracts of both wild and in vitro-derived plants showed promising photoprotective activity against UV-B and UV-A radiations in vitro with comparatively higher sun protection factor (SPF). Furthermore, GC-MS analysis of methanolic extracts of leaves and stems of wild as well as in vitro-derived plantlets revealed presence of many bioactive metabolites such as, dietary fatty acids, α-hydroxy acids, phenolic acids, sterols, amino acids, sugars and glycosides which substantially explain the use of M. acuminata as one of the potential rejuvenator and anti-aging ingredient in many Ayurvedic formulations.

Mouse models of UV-induced melanoma: genetics, pathology, and clinical relevance

Melanocytes, a neural crest cell derivative, produce pigment to protect keratinocytes from ultraviolet radiation (UVR). Although melanocytic lesions such as nevi and cutaneous malignant melanomas are known to be associated with sun exposure, the role of UVR in oncogenesis is complex and has yet to be clearly elucidated. UVR appears to have a direct mutational role in inducing or promoting melanoma formation as well as an indirect role through microenvironmental changes. Recent advances in the modeling of human melanoma in animals have built platforms upon which prospective studies can begin to investigate these questions. This review will focus exclusively on genetically engineered mouse models of UVR-induced melanoma. The role that UVR has in mouse models depends on multiple factors, including the waveband, timing, and dose of UVR, as well as the nature of the oncogenic agent(s) driving melanomagenesis in the model. Work in the field has examined the role of neonatal and adult UVR, interactions between UVR and common melanoma oncogenes, the role of sunscreen in preventing melanoma, and the effect of UVR on immune function within the skin. Here we describe relevant mouse models and discuss how these models can best be translated to the study of human skin and cutaneous melanoma.

Epithelial-mesenchymal interaction mechanisms leading to the over-expression of neprilysin are involved in the UVB-induced formation of wrinkles in the skin

In clinical studies, the formation of facial wrinkles has been closely linked to the loss of elastic properties of the skin. Repetitive UVB irradiation of animal skin at suberythemal doses significantly reduces its elastic properties, resulting in the formation of wrinkles. That also elicits a marked alteration in the three-dimensional structure of elastic fibres, which is closely associated with a subsequent reduction in the elastic properties of the skin. While UVB irradiation stimulates the activity of skin fibroblast-derived elastase in the dermis, a synthetic inhibitor specific for skin fibroblast-derived elastase as well as an extract of Zingiber officinale (L.) Rose capable of inhibiting skin fibroblast-derived elastase, but not neutrophil elastase, prevented wrinkle formation in our studies of animal and human facial skin, respectively. The close interrelationship among wrinkle formation, elastic properties and elastic fibre linearity is revealed by the effects of different concentrations of the elastase inhibitor, which indicates that enhanced elastase activity by dermal fibroblasts plays a pivotal role in the UVB wrinkling mechanism. Fortunately, we were able to identify human skin fibroblast-derived elastase as the previously known enzyme neprilysin/neutral endopeptidase. Using both a UVB-conditioned medium assay and a co-culture system, we characterized the epithelial-mesenchymal interaction between keratinocytes and fibroblasts which leads to increased expression of neprilysin at the transcriptional, translational and enzymatic levels. Our results demonstrate that interleukin-1α and granulocyte-macrophage colony-stimulating factor are intrinsic cytokines secreted by UVB-exposed keratinocytes that stimulate the expression of neprilysin by skin fibroblasts.

Molecular Mechanisms of Stress-Responsive Changes in Collagen and Elastin Networks in Skin

Collagen and elastin networks make up the majority of the extracellular matrix in many organs, such as the skin. The mechanisms which are involved in the maintenance of homeostatic equilibrium of these networks are numerous, involving the regulation of genetic expression, growth factor secretion, signalling pathways, secondary messaging systems, and ion channel activity. However, many factors are capable of disrupting these pathways, which leads to an imbalance of homeostatic equilibrium. Ultimately, this leads to changes in the physical nature of skin, both functionally and cosmetically. Although various factors have been identified, including carcinogenesis, ultraviolet exposure, and mechanical stretching of skin, it was discovered that many of them affect similar components of regulatory pathways, such as fibroblasts, lysyl oxidase, and fibronectin. Additionally, it was discovered that the various regulatory pathways intersect with each other at various stages instead of working independently of each other. This review paper proposes a model which elucidates how these molecular pathways intersect with one another, and how various internal and external factors can disrupt these pathways, ultimately leading to a disruption in collagen and elastin networks.

Soluble Vascular Endothelial Cadherin as a New Biomarker of Irradiation in Highly Irradiated Baboons with Bone Marrow Protection

Vascular endothelial cadherin is the main component of adherens junctions enabling cohesion of the endothelial monolayer in vessels. The extracellular part of vascular endothelial cadherin (VE-cadherin) can be cleaved, releasing soluble fragments in blood (sVE-cadherin). In some diseases with endothelial dysfunction, a correlation between increased blood sVE-cadherin levels and disease state has been proposed. Irradiation is known to induce endothelial damage, but new serum biomarkers are needed to evaluate endothelial damage after irradiation. Here, the authors investigated whether sVE-cadherin may be an interesting biomarker of irradiation in highly irradiated baboons with bone marrow protection. sVE-cadherin was detected in the plasma of young as well as old baboons. Plasma sVE-cadherin levels significantly decrease a few days after irradiation but recover in the late time after irradiation. Kinetic analysis of plasma sVE-cadherin levels suggests a correlation with white blood cell counts in both the acute phase of irradiation and during hematopoietic recovery, suggesting that plasma sVE-cadherin levels may be partly linked to the disappearance and recovery of white blood cells. Interestingly, after hematopoietic recovery was completed, sVE-cadherin levels were found to exceed control values, suggesting that plasma sVE-cadherin may represent a new biomarker of endothelial damage or neovascularization in the late time after irradiation.

Oxidative stress in aging human skin

Oxidative stress in skin plays a major role in the aging process. This is true for intrinsic aging and even more for extrinsic aging. Although the results are quite different in dermis and epidermis, extrinsic aging is driven to a large extent by oxidative stress caused by UV irradiation. In this review the overall effects of oxidative stress are discussed as well as the sources of ROS including the mitochondrial ETC, peroxisomal and ER localized proteins, the Fenton reaction, and such enzymes as cyclooxygenases, lipoxygenases, xanthine oxidases, and NADPH oxidases. Furthermore, the defense mechanisms against oxidative stress ranging from enzymes like superoxide dismutases, catalases, peroxiredoxins, and GSH peroxidases to organic compounds such as L-ascorbate, α-tocopherol, beta-carotene, uric acid, CoQ10, and glutathione are described in more detail. In addition the oxidative stress induced modifications caused to proteins, lipids and DNA are discussed. Finally age-related changes of the skin are also a topic of this review. They include a disruption of the epidermal calcium gradient in old skin with an accompanying change in the composition of the cornified envelope. This modified cornified envelope also leads to an altered anti-oxidative capacity and a reduced barrier function of the epidermis.

Biological mechanisms underlying the ultraviolet radiation-induced formation of skin wrinkling and sagging I: reduced skin elasticity, highly associated with enhanced dermal elastase activity, triggers wrinkling and sagging

The repetitive exposure of skin to ultraviolet B (UVB) preferentially elicits wrinkling while ultraviolet A (UVA) predominantly elicits sagging. In chronically UVB or UVA-exposed rat skin there is a similar tortuous deformation of elastic fibers together with decreased skin elasticity, whose magnitudes are greater in UVB-exposed skin than in UVA-exposed skin. Comparison of skin elasticity with the activity of matrix metalloproteinases (MMPs) in the dermis of ovariectomized rats after UVB or UVA irradiation demonstrates that skin elasticity is more significantly decreased in ovariectomized rats than in sham-operated rats, which is accompanied by a reciprocal increase in elastase activity but not in the activities of collagenases I or IV. Clinical studies using animal skin and human facial skin demonstrated that topical treatment with a specific inhibitor or an inhibitory extract of skin fibroblast-derived elastase distinctly attenuates UVB and sunlight-induced formation of wrinkling. Our results strongly indicated that the upregulated activity of skin fibroblast-derived elastase plays a pivotal role in wrinkling and/or sagging of the skin via the impairment of elastic fiber configuration and the subsequent loss of skin elasticity.

A genetic anomaly of oriented collagen biosynthesis and cross-linking: Keratoconus

Oriented collagen biosynthesis is one of the major mechanisms involved in tissue and organ formation during development. Corneal biogenesis is one example. Defects in this process lead to anomalies in tissue structure and function. The transparency of cornea and its achievement are a good example as well as its pathological modifications. Keratoconus is one example of this type of pathologies, involving also inappropriate cross-linking of collagen fibers. Among the tentatives to correct this anomaly, the riboflavin-potentiated UV-cross-linking (CXL) of keratoconus corneas appears clinically satisfactory, although none of the experiments and clinical results published prove effective cross-linking. The published results are reviewed in this article.

Chemical Constituents of Tilia taquetii Leaves and their Inhibition of MMP-1 Expression and Elastase Activities

The ethanol extract of Tilia taquetii Schneider leaves was investigated for its anti-wrinkle properties and for the relevant chemical constituents. Phytochemical studies led to the identification of five known compounds, viz. phytol (1), isoquercitrin (2), oleanderolide (3), arjunolic acid (4) and maslinic acid (5) from the extract. Of these, compounds 4 and 5 inhibited the expression of matrix metalloproteinase-1 (MMP-1), an enzyme responsible for the breakdown of collagen fiber. Moreover, compound 5 showed inhibition activity on elastase, a protease enzyme capable of degrading elastin. These results suggest that the extract of T. taquetii containing the triterpenes 4 and 5 could be applied as anti-wrinkle ingredients in cosmetic preparations.

Beneficial Regulation of Elastase Activity and Expression of Tissue Inhibitors of Matrixmetalloproteinases, Fibrillin, Transforming Growth Factor-β, and Heat Shock Proteins by P. leucotomos in Nonirradiated or Ultraviolet-Radiated Epidermal Keratinocytes

There is loss of the structural integrity of the extracellular matrix (ECM) with intrinsic aging as well as photoaging, largely due to reactive oxygen species (ROS). The structural ECM proteins include the microfibrils that are composed of fibrillin. The structural ECM proteins are primarily degraded by the matrixmetalloproteinases (MMPs) and elastase enzymes. The MMPs are inhibited by the tissue inhibitors of MMPs (TIMPs). A primary regulator of the ECM proteins is transforming growth factor-β (TGF-β), and the chaperone proteins important for its formation are the heat shock proteins (HSP). P. leucotomos extract beneficially regulates of MMPs, TIMPs, and TGF-β in nonirradiated or ultraviolet (UV) radiated fibroblasts and melanoma cells. The hypothesis of this research was that the antioxidant activity or chemistry of P. leucotomos extract would also directly inhibit elastase activity, stimulate the cellular expression of TIMPs, fibrillins, and TGF-β, and regulate HSPs in nonirradiated and UVA or UVB radiated epidermal keratinocytes. P. leucotomos directly inhibited elastase activity, stimulated the cellular expression of TIMPs, fibrillins, and TGF-β, and differentially regulated HSPs in nonirradiated and UVA or UVB radiated epidermal keratinocytes. We infer that the P. leucotomos extract strengthens the ECM and is effective in the prevention or treatment of intrinsic and photoaging of skin.

In vitro determination of the anti-aging potential of four southern African medicinal plants

Background

Aging is an inevitable process for all living organisms. During this process reactive oxygen species generation is increased which leads to the activation of hyaluronidase, collagenase and elastase, which can further contribute to skin aging. Four southern African medicinal plants; Clerodendrum glabrum, Schotia brachypetala, Psychotria capensis and Peltophorum africanum, were investigated to assess their anti-aging properties.

Methods

Anti-elastase, anti-collagenase and anti-hyaluronidase activities of twenty-eight samples, consisting of methanol and ethyl acetate extracts of the four plants, were determined using spectrophotometric methods. Radical scavenging activity was determined by the ability of the plant extracts to scavenge the ABTS^•+ radical.

Results

The majority of the samples in the anti-elastase assay and nine in the anti-collagenase assay showed more than 80% inhibition. The ethyl acetate extract of S. brachypetala bark and leaves of P. capensis inhibited elastase activity by more than 90%. The methanol extract of S. brachypetala bark contained the highest anti-hyaluronidase activity (75.13 ± 7.49%) whilst the ethyl acetate extract of P. africanum bark exhibited the highest antioxidant activity (IC₅₀: 1.99 ± 0.23 μg/ml).

Conclusion

The free radical scavenging activity and enzyme inhibitory activity of the plant extracts investigated suggests that they can help restore skin elasticity and thereby slow the wrinkling process. P. africanum was the plant with the most promising activity and will be subjected to further testing and isolation of the active compound/s.

Effects of collagen and collagen hydrolysate from jellyfish umbrella on histological and immunity changes of mice photoaging

Jellyfish collagen (JC) was extracted from jellyfish umbrella and hydrolyzed to prepare jellyfish collagen hydrolysate (JCH). The effects of JC and JCH on UV-induced skin damage of mice were evaluated by the skin moisture, microscopic analyses of skin and immunity indexes. The skin moisture analyses showed that moisture retention ability of UV-induced mice skin was increased by JC and JCH. Further histological analysis showed that JC and JCH could repair the endogenous collagen and elastin protein fibers, and could maintain the natural ratio of type I to type III collagen. The immunity indexes showed that JC and JCH play a role in enhancing immunity of photoaging mice in vivo. JCH showed much higher protective ability than JC. These results suggest that JCH as a potential novel antiphotoaging agent from natural resources.

Determination of Hexapeptide ALA-ASP-LEU-LYS-PRO-THR by MALDI MS

The hexapeptide ALA-ASP-LEU-LYS-PRO-THR is currently widely used as an active ingredient in commercially available creams. Therefore, the proper analytical procedure to detect this compound is a very important issue. This paper presents the determination of the hexapeptide in solution and in cosmetic formulations by matrix assisted laser desorption ionisation mass spectrometry. We developed a procedure for the selective binding of the low molecular weight peptide by using a two-component matrix which enabled us to characterize the hexapeptide directly without any initial processing. Furthermore, the extensive computer simulations were carried out to assist in this analysis of the MS spectra.

The endogenous protease inhibitor TIMP-1 mediates protection and recovery from cutaneous photodamage

UVB exposure is well known to induce skin photodamage and photoaging that correlates with qualitative and quantitative deterioration of the dermal extracellular matrix (ECM) because of the upregulation of matrix metalloproteinases (MMPs). Although inhibitory effects of tissue inhibitor of metalloproteinases (TIMPs) on most MMPs have been reported, the protective role of TIMP-1 against photodamage is poorly understood. To address this, TIMP-1 function was augmented or abolished in a human skin xenograft photodamage model after the confirmation of significantly diminished TIMP-1 expression both in photoaged and intrinsically aged skins. During a chronic UVB exposure regimen, pre-treatment with a lentiviral vector overexpressing TIMP-1 or concomitant administration of an anti-TIMP-1-neutralizing antibody (NAB) led to photoprotection or more severe photodamage, respectively. Overexpression of TIMP-1 resulted in significant inhibition of UVB-induced ECM degradation, as well as suppression of decreased skin elasticity and roughness, whereas the NAB-mediated inhibition of TIMP-1 had opposite effects. Furthermore, UVB-induced production of the pro-inflammatory cytokine, tumor necrosis factor α, was inhibited by TIMP-1 treatment of human keratinocytes. Taken together, these data shed light on the important role of TIMP-1 in protection and recovery from cutaneous photodamage because of its suppression of ECM degradation and inflammation.

Moisture absorption and retention properties, and activity in alleviating skin photodamage of collagen polypeptide from marine fish skin

Collagen polypeptides were prepared from cod skin. Moisture absorption and retention properties of collagen polypeptides were determined at different relative humidities. In addition, the protective effects of collagen polypeptide against UV-induced damage to mouse skin were evaluated. Collagen polypeptides had good moisture absorption and retention properties and could alleviate the damage induced by UV radiation. The action mechanisms of collagen polypeptide mainly involved enhancing immunity, reducing the loss of moisture and lipid, promoting anti-oxidative properties, inhibiting the increase of glycosaminoglycans, repairing the endogenous collagen and elastin protein fibres, and maintaining the ratio of type III to type I collagen.

Physiology of skin aging

Skin is the most voluminous organ of the body. It assumes several important physiological functions and represents also a "social interface" between an individual and other members of society. This is the main reason its age-dependent modifications are in the forefront of dermatological research and of the "anti-aging" cosmetic industry. Here we concentrate on some aspects only of skin aging, as far as the cellular and extracellular matrix components of skin are concerned. Most well studied mechanisms of skin aging can be situated at the postgenetic level, both epigenetic and post-translational mechanisms being involved. Some of these mechanisms will be reviewed as well as the capacity of fucose- and rhamnose-rich oligo- and polysaccharides (FROP and RROP) to counteract several of the mechanisms involved in skin aging.

Essential role of microfibrillar-associated protein 4 in human cutaneous homeostasis and in its photoprotection

UVB-induced cutaneous photodamage/photoaging is characterized by qualitative and quantitative deterioration in dermal extracellular matrix (ECM) components such as collagen and elastic fibers. Disappearance of microfibrillar-associated protein 4 (MFAP-4), a possible limiting factor for cutaneous elasticity, was documented in photoaged dermis, but its function is poorly understood. To characterize its possible contribution to photoprotection, MFAP-4 expression was either augmented or inhibited in a human skin xenograft photodamage murine model and human fibroblasts. Xenografted skin with enhanced MFAP-4 expression was protected from UVB-induced photodamage/photoaging accompanied by the prevention of ECM degradation and aggravated elasticity. Additionally, remarkably increased or decreased fibrillin-1-based microfibril development was observed when fibroblasts were treated with recombinant MFAP-4 or with MFAP-4-specific siRNA, respectively. Immunoprecipitation analysis confirmed direct interaction between MFAP-4 and fibrillin-1. Taken together, our findings reveal the essential role of MFAP-4 in photoprotection and offer new therapeutic opportunities to prevent skin-associated pathologies.

Age- and passage-dependent upregulation of fibroblast elastase-type endopeptidase activity. Role of advanced glycation endproducts, inhibition by fucose- and rhamnose-rich oligosaccharides

It could be shown using the in vitro cell culture aging model, that elastase-type endopeptidase activity is progressively upregulated with successive passages (in vitro aging). Similar results were obtained previously by determining elastase-type activity as a function of age in aorta extracts (human) and skin extracts (mouse). Among the possible mechanisms involved we tested the role of advanced glycation endproducts (AGEs) on this process. AGE-production was shown to increase with age, exemplified by the exponential age-dependent crosslinking of collagen, demonstrated by Fritz Verzár, already in 1963. Several AGEs significantly upregulated elastase-type activity when added to the culture medium of fibroblasts. This effect appears to be mediated by some AGE-receptors as shown previously, and could be inhibited by a 5 kDa rhamnose-rich oligosaccharide (RROP-3) as well as by a fucose-rich oligosaccharide (FROP-3). When present in the culture media, RROP-3 and FROP-3 efficiently inhibited the passage-dependent upregulation of elastase-type activity expressed by human skin fibroblasts. The use of specific inhibitors and zymography suggested that matrix metalloproteinases (MMP)-9 activation and expression are mainly involved. A detailed discussion is proposed for the interpretation of age-dependent modifications of tissues as vascular wall and skin in the light of these and related experiments, highlighting the role of several specific receptors in the mediation of the observed reactions.

Aplicação de métodos de biofísica no estudo da eficácia de produtos dermocosméticos

O trabalho aborda a aplicação dos métodos de biofísica no estudo de eficácia de produtos dermocosméticos. A qualidade de um produto cosmético engloba a segurança de seu uso, a estabilidade da formulação, o aspecto, o sensorial e a sua eficácia. As técnicas de biofísica têm sido amplamente empregadas na avaliação do efeito de formulações dermocosméticas, principalmente devido ao fato de possibilitarem a avaliação de produtos em suas reais condições de uso, ou seja, na pele humana. A comprovação dos efeitos de produtos cosméticos e a elucidação de seu mecanismo de ação por meio de protocolos experimentais devidamente elaborados, que utilizem as técnicas de biofísica da pele, dentre outras, tornam-se de fundamental importância e, assim, a serem amplamente exploradas e ainda bastante desenvolvidas, visando à melhoria da qualidade de vida dos usuários de tais produtos.

Mechanistic effects of long-term ultraviolet B irradiation induce epidermal and dermal changes in human skin xenografts

UVB irradiation has been reported to induce photoaging and suppress systemic immune function that could lead to photocarcinogenesis. However, because of the paucity of an UVB-induced photodamaged skin model, precise and temporal mechanism(s) underlying the deleterious effects of long-term UVB exposure on human skin have yet to be delineated. In this study, we established a model using human skin xenografted onto severe combined immunodeficient mice, which were subsequently challenged by repeated UVB irradiation for 6 weeks. Three-dimensional optical image analysis of skin replicas and noninvasive biophysical measurements illustrated a significant increase in skin surface roughness, similar to premature photoaging, and a significant loss of skin elasticity after long-term UVB exposure. Resembling authentically aged skin, UVB-exposed samples exhibited significant increases in epithelial keratins (K6, K16, K17), elastins, and matrix metalloproteinases (MMP-1, MMP-9, MMP-12) as well as degradation of collagens (I, IV, VII). The UVB-induced deterioration of fibrous keratin intermediate filaments was also observed in the stratum corneum. Additionally, similarities in gene expression patterns between our model and chronologically aged skin substantiated the plausible relationship between photodamage and chronological age. Furthermore, severe skin photodamage was observed when neutralizing antibodies against TIMP-1, an endogenous inhibitor of MMPs, were administered during the UVB exposure regimen. Taken together, these findings suggest that our skin xenograft model recapitulates premature photoaged skin and provides a comprehensive tool with which to assess the deleterious effects of UVB irradiation.

Kinetics and Mechanism of the Addition of Nucleophiles to α,β-Unsaturated Thiol Esters

Compounds containing the UV-absorbing chromophores p-methoxycinnamate, p-methoxycinnamide, or anthranilate and an alpha,beta- or alpha,beta,gamma,delta-unsaturated thiol ester (crotonyl or sorboyl) have been prepared. These compounds are subject to nucleophilic attack at the C=C conjugated to the thiol ester carbonyl group. The kinetics of the reactions of these thiol esters with N-acetyl-l-cysteine (NAC), N-acetylcysteamine, and N(2)-acetyl-L-lysine (NAL) have been studied, and the thiol addition products have been identified. The reaction rates increased at higher pH, and the reaction of NAC thiolate with a crotonyl thiol ester in 1:1 (v/v) acetonitrile/aqueous HEPES exhibited buffer catalysis as a result of protonation of the enolate intermediate. At the same concentration, NAC underwent approximately 300-fold more reaction than NAL with a crotonyl thiol ester at pH 9.8. Additionally, a crotonyl thiol ester was found to be 7.9 times more reactive than a sorboyl thiol ester toward NAC addition. These unsaturated thiol esters may serve as a means of covalently binding UVA and UVB sunscreens to the outer layer of skin to provide long-lasting protection.