The skin as a mirror of the aging process in the human organism--state of the art and results of the aging research in the German National Genome Research Network 2 (NGFN-2)

Radiofrequency Treatment Attenuates Age-Related Changes in Dermal-Epidermal Junctions of Animal Skin

The dermal-epidermal junction (DEJ) is essential for maintaining skin structural integrity and regulating cell survival and proliferation. Thus, DEJ rejuvenation is key for skin revitalization, particularly in age-related DEJ deterioration. Radiofrequency (RF) treatment, known for its ability to enhance collagen fiber production through thermal mechanisms and increase heat shock protein (HSP) expression, has emerged as a promising method for skin rejuvenation. Additionally, RF activates Piezo1, an ion channel implicated in macrophage polarization toward an M2 phenotype and enhanced TGF-β production. This study investigated the impact of RF treatment on HSP47 and HSP90 expression, known stimulators of DEJ protein expression. Furthermore, using in vitro and aged animal skin models, we assessed whether RF-induced Piezo1 activation and the subsequent M2 polarization could counter age-related DEJ changes. The RF treatment of H2O2-induced senescent keratinocytes upregulated the expression of HSP47, HSP90, TGF-β, and DEJ proteins, including collagen XVII. Similarly, the RF treatment of senescent macrophages increased Piezo1 and CD206 (M2 marker) expression. Conditioned media from RF-treated senescent macrophages enhanced the expression of TGF-β and DEJ proteins, such as nidogen and collagen IV, in senescent fibroblasts. In aged animal skin, RF treatment increased the expression of HSP47, HSP90, Piezo1, markers associated with M2 polarization, IL-10, and TGF-β. Additionally, RF treatment enhanced DEJ protein expression. Moreover, RF reduced lamina densa replication, disrupted lesions, promoted hemidesmosome formation, and increased epidermal thickness. Overall, RF treatment effectively enhanced DEJ protein expression and mitigated age-related DEJ structural changes by increasing HSP levels and activating Piezo1.

Synthesis and characterization of a bovine collagen: GAG scaffold with Uruguayan raw material for tissue engineering

Tissue engineering (TE) and regenerative medicine offer strategies to improve damaged tissues by using scaffolds and cells. The use of collagen-based biomaterials in the field of TE has been intensively growing over the past decades. Mesenchymal stromal cells (MSCs) and dental pulp stem cells (DPSCs) are promising cell candidates for development of clinical composites. In this study, we proposed the development of a bovine collagen type I: chondroitin-6-sulphate (CG) scaffold, obtained from Uruguayan raw material (certified as free bovine spongiform encephalopathy), with CG crosslinking enhancement using different gamma radiation doses. Structural, biomechanical and chemical characteristics of the scaffolds were assessed by Scanning Electron Microscopy, axial tensile tests, FT-IR and Raman Spectroscopy, respectively. Once we selected the most appropriate scaffold for future use as a TE product, we studied the behavior of MSCs and DPSCs cultured on the scaffold by cytotoxicity, proliferation and differentiation assays. Among the diverse porous scaffolds obtained, the one with the most adequate properties was the one exposed to 15 kGy of gamma radiation. This radiation dose contributed to the crosslinking of molecules, to the formation of new bonds and/or to the reorganization of the collagen fibers. The selected scaffold was non-cytotoxic for the tested cells and a suitable substrate for cell proliferation. Furthermore, the scaffold allowed MSCs differentiation to osteogenic, chondrogenic, and adipogenic lineages. Thus, this work shows a promising approach to the synthesis of a collagen-scaffold suitable for TE.

Preventive effect of human umbilical cord mesenchymal stem cells on skin aging in rats

The irreversibility of aging makes anti-aging become an important research direction in the field of medical research. As the most direct manifestation of human aging, skin aging has been paid more and more attention. Stem cells have been used as a basis for anti-aging studies in skin, of which adipose-derived mesenchymal stem cells are more commonly used. In this study, human umbilical cord mesenchymal stem cells were used, and human umbilical cord mesenchymal stem cells were intervened while making a skin aging model, which was planned to reduce the process of preventing skin aging in the study method. At the end of the experiment, rat skin and serum were taken for relevant data detection. The results showed that the contents of EGF and VEGF in serum and skin tissue of rats increased and the content of MDA decreased after the application of human umbilical cord mesenchymal stem cells. At the same time, hUCMSC intervention increased skin thickness, increased dermal vessels, increased type I collagen type III collagen mRNA expression, and decreased MMP-1 content in rats. The results showed that hUCMSC could prevent skin aging in rats.

[Skin aging-cellular senescence : What is the future?]

BACKGROUND

Cellular senescence is the main cause of skin and organ aging and is associated with a wide range of aging-related diseases.

OBJECTIVES

To understand which senolytics, senomorphics, and cell-based therapies have been developed to alleviate and even rejuvenate skin aging and reduce cellular senescence.

METHODS

Basic literature for the mode of action of senolytics and senomorphics and their clinical perspectives in daily routine are discussed.

RESULTS

Various causes lead to mitochondrial dysfunction and the activation of pro-aging signaling pathways, which eventually lead to cellular senescence with degradation of structural proteins of the dermal connective tissue and severe suppression of regenerative stem cell niches of the skin.

CONCLUSIONS

Depletion of senescent cells suppress skin aging and enforce rejuvenation of skin and other organs and their function. The removal of senescent cells by cells of the native immune system is severely disturbed during aging. Selected senolytics and senomorphics are approved and are already on the market.

The Association between the Level of Advanced Glycation End Products and Objective Skin Quality Parameters

Advanced glycation end products (AGEs) represent an endogenously produced or exogenously derived group of compounds derived from nonenzymatic glycation. Recent experimental studies are suggesting that AGEs could play an important role in the skin's quality and its aging process. Hence, the aim of this study was to clinically evaluate the AGEs and skin quality parameters across different age groups in the general population. The study included 237 participants. Melanin, erythema, hydration, friction and transepidermal water loss (TEWL) were evaluated using noninvasive probes, while AGEs were evaluated using a skin autofluorescence reader. There was a significant positive correlation between AGEs and the amount of melanin (p < 0.001), erythema (p < 0.001) and TEWL (p < 0.001), while there was a significant negative correlation between AGEs and hydration (p < 0.001) and friction (p < 0.001). After dividing the sample into three groups depending on their age, in all three groups, there was a significant positive correlation between AGEs and the melanin count (p < 0.001) and TEWL (p < 0.001), while there was a significant negative correlation between AGEs and skin hydration (p < 0.001). Multiple linear regression analysis showed that the level of AGEs as a dependent variable retained a significant association with age (p < 0.001), melanin (p < 0.001), erythema (p = 0.005) and TEWL (p < 0.001) as positive predictors. Moreover, AGEs retained a significant association with skin hydration (p < 0.001) and friction (p = 0.017) as negative predictors. These outcomes imply that AGEs could be linked with the complex physiology of the skin and its aging process.

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.

Application of Sebum Lipidomics to Biomarkers Discovery in Neurodegenerative Diseases

Lipidomics is strategic in the discovery of biomarkers of neurodegenerative diseases (NDDs). The skin surface lipidome bears the potential to provide biomarker candidates in the detection of pathological processes occurring in distal organs. We investigated the sebum composition to search diagnostic and, possibly, prognostic, biomarkers of Alzheimer’s disease (AD) and Parkinson’s disease (PD). The observational study included 64 subjects: 20 characterized as “probable AD with documented decline”, 20 as “clinically established PD”, and 24 healthy subjects (HS) of comparable age. The analysis of sebum by GCMS and TLC retrieved the amounts (µg) of 41 free fatty acids (FFAs), 7 fatty alcohols (FOHs), vitamin E, cholesterol, squalene, and total triglycerides (TGs) and wax esters (WEs). Distributions of sebum lipids in NDDs and healthy conditions were investigated with multivariate ANOVA-simultaneous component analysis (ASCA). The deranged sebum composition associated with the PD group showed incretion of most composing lipids compared to HS, whereas only two lipid species (vitamin E and FOH14:0) were discriminant of AD samples and presented lower levels than HS sebum. Thus, sebum lipid biosynthetic pathways are differently affected in PD and AD. The characteristic sebum bio-signatures detected support the value of sebum lipidomics in the biomarkers search in NDDs.

Acne Syndromes and Mosaicism

Abnormal mosaicism is the coexistence of cells with at least two genotypes, by the time of birth, in an individual derived from a single zygote, which leads to a disease phenotype. Somatic mosaicism can be further categorized into segmental mosaicism and nonsegmental somatic mosaicism. Acne is a chronic illness characterized by inflammatory changes around and in the pilosebaceous units, commonly due to hormone- and inflammatory signaling-mediated factors. Several systemic disorders, such as congenital adrenal hyperplasia, polycystic ovarian syndrome, and seborrhoea-acne-hirsutism-androgenetic alopecia syndrome have classically been associated with acne. Autoinflammatory syndromes, including PAPA, PASH, PAPASH, PsAPASH, PsaPSASH, PASS, and SAPHO syndromes include acneiform lesions as a key manifestation. Mosaic germline mutations in the FGFR2 gene have been associated with Apert syndrome and nevus comedonicus, two illnesses that are accompanied by acneiform lesions. In this review, we summarize the concept of cutaneous mosaicism and elaborate on acne syndromes, as well as acneiform mosaicism.

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.

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.

Air Pollution and Skin Aging

PURPOSE OF THE REVIEW

The evidence on the role of air pollution on skin aging has increased in recent years. The accumulating evidence is based on both, epidemiological and mechanistic studies. The purpose of this review is to evaluate the recent evidence on the impacts of air pollution on skin aging as well as identify knowledge gaps for future research.

RECENT FINDINGS

Traffic-related air pollution exposure (particulate matter (PM), soot and nitrogen dioxide (NO₂)) has been associated with premature skin aging in several independent cohorts. In real life, human skin is additionally exposed to UV radiation, which is known for its effects on premature skin aging. More recent epidemiological findings suggest that (1) associations of PM can be altered by UV radiation with stronger PM associations at lower levels of UV, and (2) there is an association of tropospheric ozone with wrinkle formation, independent of NO₂, PM, and UV. The association between traffic-related air pollution and skin aging has been well-established. More recent epidemiological studies focused on the associations with ozone as well as interactions with of ambient air pollution with UV radiation, a research area that is becoming more important with the increase of global warming.

Morphological and Functional Changes in Skin of Adult Male Rats Chronically Treated with Letrozole, a Nonsteroidal Inhibitor of Cytochrome P450 Aromatase

Skin is a target for hormones and a site of hormone production. Aromatase inhibitors such as letrozole reduce circulating estrogen. The aim of the study was to investigate the morphology of the dermis and immunoexpression of androgen receptor (AR), estrogen receptor α and β (ERα, ERβ), luteinizing hormone receptor (LHR), follicle-stimulating hormone receptor (FSHR), and cytochrome P450 aromatase (P450arom) in male rats with a deficit of estradiol. Experiments were performed on skin of 12 male rats. Rats in the experimental group received per os letrozole for 6 months. For morphological analysis, van Gieson, Sirius Red and orcein staining of sections was performed. In immunohistochemistry, reactions with specific antibodies (anti-P450arom, LHR, FSHR, ERα, ERβ) were used. In morphometric analysis, sections were stained with hematoxylin and eosin. Differences between groups were assessed by Mann-Whitney U-test. There were no differences in the diameter of collagen fibers. The dermis of letrozole-treated animals showed areas without collagen fibers, and expression of P450arom, ERα and ERβ was diminished in the skin of these animals. This study indicates that estrogens exert an effect via ERs that has a role in maintaining proper skin morphology in males, together with androgen. This is also the first documented expression of FSHR in the skin of male rats.

Cellular Function of Annexin A1 Protein Mimetic Peptide Ac2-26 in Human Skin Keratinocytes HaCaT and Fibroblast Detroit 551 Cells

Inflammation of the skin is the most common dermatological problem in human. The anti-inflammatory mediated responses of the skin cells provide a mechanism for combating these conditions. Annexin A1 (AnxA1) is one of the proteins that has been shown to have a potent anti-inflammatory effect. However, the effects and mechanisms of AnxA1 in skin keratinocyte and fibroblast have not been reported yet. In the current study, we hypothesized that Ac2-26, AnxA1 mimetic peptide, ameliorates inflammation and wrinkle formation in human skin cells. Therefore, we aimed to identify whether Ac2-26 has anti-inflammatory and anti-wrinkle effects in human keratinocyte (HaCaT) and fibroblast (Detroit 551) cells, respectively. Human HaCaT cells were stimulated by TNF-α/IFN-γ with or without Ac2-26, to identify the anti-inflammatory effect. Human Detroit 551 cells were treated with Ac2-26 to verify the anti-wrinkle effect. Initially, cell cytotoxicity was carried out in each cell line treated using Ac2-26 by MTT assay. Human MDA, IL-8, and procollagen secretion were detected by ELISA assay. The inflammatory chemokines were measured by qRT-PCR analysis. To demonstrate the mechanism, MAPK, NF-κB, JAK/STAT, and MMPs were analyzed by Western blotting. As a result, we identified that Ac2-26 significantly decreased the expression of TNF-α/IFN-γ-stimulated pro-inflammatory chemokines, including IL-1β, IL-6, IL-8, MDC, TARC, and TNF-α, by inhibiting the activation of MAPK, NF-κB, and JAK/STAT pathway in TNF-α/IFN-γ-stimulated HaCaT human keratinocytes. In addition, we also identified that Ac2-26 significantly induced collagen synthesis by generating pro-collagen, and suppressed collagen degradation by inhibiting the collagenase MMP-1 and MMP-8 expression. Collectively, these results suggest that Ac2-26 shows anti-inflammatory and anti-wrinkling effect. These effects may lead to the development of preventive and therapeutic application for inflammation-related skin disease and wrinkle formation.

Lycopene and Melatonin: Antioxidant Compounds in Cosmetic Formulations

BACKGROUND

The use of antioxidants has become a common practice in the development of antiaging cosmetics.

OBJECTIVE

The aim of this study was to evaluate the clinical efficacy of cosmetic formulations containing lycopene and melatonin antioxidants.

METHOD

Thirty-six healthy women from 32 to 65 years were enrolled in this study. The study was carried out for 10 weeks, 2 preconditioning weeks with a control cream without antioxidants, and 8-week test with creams containing antioxidants in study. A multifunctional skin physiology monitor (Courage &amp; Khazaka electronic GmbH®, Germany) was used to measure skin sebum content, hydration, elasticity, erythema index, and melanin index in 4 different regions of the face.

RESULTS

There were significant differences between them.

The Pathobiology of Skin Aging: New Insights into an Old Dilemma

Long considered both physiologic and inevitable, skin aging is a degenerative phenomenon whereby both intrinsic and environmental factors conspire to produce an authentic disease. The consequences of this disorder are many and varied, ranging from atrophy and fragility to defective repair to deficient immunity and vulnerability to certain infections. The pathobiologic basis for skin aging remains poorly understood. At a cellular level, stem cell dysfunction and attrition appear to be key events, and both genetic and epigenetic factors are involved in a complex interplay that over time results in deterioration of our main protective interface with the external environment. Past and current understanding of the cellular and molecular intricacies of skin aging provide a foundation for future approaches designed to thwart the aging phenotype. Herein, the authors provide a review of current insights into skin aging, including the mechanisms of skin aging, the role of stem cells in skin aging and the implications of skin aging for the microbiome and for the development of cancer. Conquest of the oft overlooked disease of skin aging should have broad implications that transcend the integument and inform novel approaches to retarding aging and age-related dysfunction in those internal organs that youthful skin was designed to envelop and safeguard.

Shedding Light on the Effects of Calorie Restriction and its Mimetics on Skin Biology

During the aging process of an organism, the skin gradually loses its structural and functional characteristics. The skin becomes more fragile and vulnerable to damage, which may contribute to age-related diseases and even death. Skin aging is aggravated by the fact that the skin is in direct contact with extrinsic factors, such as ultraviolet irradiation. While calorie restriction (CR) is the most effective intervention to extend the lifespan of organisms and prevent age-related disorders, its effects on cutaneous aging and disorders are poorly understood. This review discusses the effects of CR and its alternative dietary intake on skin biology, with a focus on skin aging. CR structurally and functionally affects most of the skin and has been reported to rescue both age-related and photo-induced changes. The anti-inflammatory, anti-oxidative, stem cell maintenance, and metabolic activities of CR contribute to its beneficial effects on the skin. To the best of the author’s knowledge, the effects of fasting or a specific nutrient-restricted diet on skin aging have not been evaluated; these strategies offer benefits in wound healing and inflammatory skin diseases. In addition, well-known CR mimetics, including resveratrol, metformin, rapamycin, and peroxisome proliferator-activated receptor agonists, show CR-like prevention against skin aging. An overview of the role of CR in skin biology will provide valuable insights that would eventually lead to improvements in skin health.

Resveratrol: from diet to topical usage

The stilbene derivative resveratrol (3,5,4'-trihydroxy-stilbene; RESV) has become the subject of interest of many researchers and the pharmaceutical industries due to its well-acclaimed beneficial biological activities. Although earlier research tended to focus on the effects of RESV on cardiovascular disorders, many other studies have described the beneficial effects of RESV in the areas of cancer chemoprevention and inflammation and interest of researchers on this compound is still increasing. It is now well accepted that the effect of RESV is not just due to its so called "antioxidant" activity but mainly (if not only) because of the ability of this compound to trigger cell signaling pathways and gene expression involved in cellular defense systems. Many "in vitro" studies on RESV did not take into account that although its oral absorption is about 75% it undergoes rapid metabolism and the concentration in the blood stream is almost undetectable. For this reason interest in the topical usage of RESV by cosmeceutical skin care brands has exponentially increased in the last decade reporting in general very promising results on its beneficial effect in protecting the skin from outdoor insults, but there is still some controversy on its topical usage mainly surrounding the concentration used. Therefore, more basic research on the topical application of RESV should be performed to better understand the way it prevents cutaneous damage and whether it could be recommended as a preventive skin aging agent for all skin insults.

Morphologic Changes in the Dermis After the Single Administration of Autologous Fibroblastic Cells: A Preliminary Study

BACKGROUND

Aging is a multifactorial process defined by an accumulation of damage in all tissues and organs, including the skin, throughout the lifespan of an individual. The reduction of both cellular and extracellular matrix components of the dermis during the aging process is followed by the alteration of the morphology of the skin tissue. This study was conducted to assess skin morphology in men before and 3 months after the intradermal injection of autologous fibroblastic cells.

METHODS

Tissue biopsies were surgically obtained before and 3 months after the treatment with autogenously harvested fibroblasts expanded in vitro, as well as after injection of phosphate-buffered saline. The thickness of collagen fiber bundles and number of fibroblasts in the dermis were analyzed in morphometric studies. The morphologic evaluation, using different methods of staining has been performed to analyze of extracellular matrix proteins, including collagen and reticular fibers, fibrillin-1-rich microfibrils, elastic fibers, and hyaluronic acid.

RESULTS

After administration of the cells, we found a noticeable increase in the number of fibroblasts within the dermis, a significant enlargement in diameter of the collagen fiber bundles, and an improvement in the density of reticular fibers, fibrillin-1-rich microfibrils, and elastic fibers compared with the initial, steady-state condition.

CONCLUSIONS

The administration of autogenous fibroblasts could be an effective and safe adjunctive therapy to conventional health care treatment to prevent and reduce the age-related accumulation of dermal tissue damage.

Skin aging caused by intrinsic or extrinsic processes characterized with functional proteomics

The skin provides protection against environmental stress. However, intrinsic and extrinsic aging causes significant alteration to skin structure and components, which subsequently impairs molecular characteristics and biochemical processes. Here, we have conducted an immunohistological investigation and established the proteome profiles on nude mice skin to verify the specific responses during aging caused by different factors. Our results showed that UVB-elicited aging results in upregulation of proliferating cell nuclear antigen and strong oxidative damage in DNA, whereas chronological aging abolished epidermal cell growth and increased the expression of caspase-14, as well as protein carbonylation. Network analysis indicated that the programmed skin aging activated the ubiquitin system and triggered obvious downregulation of 14-3-3 sigma, which might accelerate the loss of cell growth capacity. On the other hand, UVB stimulation enhanced inflammation and the risk of skin carcinogenesis. Collectively, functional proteomics could provide large-scale investigation of the potent proteins and molecules that play important roles in skin subjected to both intrinsic and extrinsic aging.

Biomarkers of skin aging

Aging is a complex process not only influenced by inherited but also by several environmental factors. It is characterized by a progressive loss of function in multiple tissues, which leads to an increased probability of death. On the other hand, several morphological and histological changes are registered in aged skin that is mostly dependent on the cumulative exposure in environmental aging promoters, such as ultraviolet radiation. Understanding of individual pathogenesis and introduction of preventive measurements require objective assessment, i.e., the administration of biomarkers. Because of the complexity of skin aging, the exact definition of biomarkers is a major research challenge. In this article, we summarize the basic knowledge involving skin aging and its biomarkers.

Aryl hydrocarbon receptor negatively regulates lipid synthesis and involves in cell differentiation of SZ95 sebocytes in vitro

The aryl hydrocarbon receptor (AhR) is the receptor for 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), benzo(a)pyrene (BaP) and other exogenous compounds. In human sebocytes, TCDD and BaP were found to activate the expression of multiple genes, including cytochrome P450 1A1 (CYP1A1), and inhibit lipid synthesis via AhR, while little is known about endogenous functions of the AhR. In order to expand this knowledge, we analyzed the impact of AhR knockdown on lipid synthesis as well as on cell differentiation of SZ95 sebocytes in vitro and observed that lipid synthesis was significantly induced in AhR silenced SZ95 sebocytes. In line with this result, expression of lipogenesis-associated genes, such as peroxisome proliferator activated receptor (PPAR) δ and PPARγ, was increased. Morphological changes with smaller cells in size but more abundant cytoplasmic lipids were observed in AhR silenced SZ95 sebocytes compared with the AhR activated cells. Besides, the expression of keratin 7, an early sebaceous differentiation marker, was increased, while the expression of the terminal sebocyte differentiation marker epithelial membrane antigen (EMA) was reduced. Moreover, the terminal keratinocyte differentiation markers keratin 10 and involucrin, and the AhR downstream protein CYP1A1 were reduced after AhR silencing. To the best of our knowledge, we provide evidence that in the absence of exogenous ligands, the AhR inhibits lipid synthesis and involves in cell differentiation of human SZ95 sebocytes, which indicates the physiological function of this receptor in human sebocytes.

Effect of a quality-controlled fermented nutraceutical on skin aging markers: An antioxidant-control, double-blind study

The aim of the present study was to determine whether oral supplementation with a fermented papaya preparation (FPP-treated group) or an antioxidant cocktail (antioxidant-control group, composed of 10 mg trans-resveratrol, 60 µg selenium, 10 mg vitamin E and 50 mg vitamin C) was able to improve the skin antioxidant capacity and the expression of key skin genes, while promoting skin antiaging effects. The study enrolled 60 healthy non-smoker males and females aged 40-65 years, all of whom showed clinical signs of skin aging. The subjects were randomly divided into two matched groups, and were administered FPP or antioxidant treatment of a 4.5 g/day sachet sublingually twice a day for 90 days in a double-blind fashion. The parameters investigated were: Skin surface, brown spots, skin evenness, skin moisturization, elasticity (face), redox balance, nitric oxide (NO) concentration, and the expression levels of key genes (outer forearm sample). As compared with the baseline (day 0) and antioxidant-control values, FPP-treated subjects showed a significant improvement in skin evenness, moisturization and elasticity. The two treatments improved the MDA and SOD skin concentrations, but only the FPP-treated group showed a higher SOD level and a significant NO increase, along with significant upregulation of acquaporin-3 and downregulation of the potentially pro-aging/carcinogenetic cyclophilin-A and CD147 genes (P<0.05). Progerin was unaffected in both treatment groups. In conclusion, these findings suggest that orally-administered FPP showed a consistent biological and gene-regulatory improvement in the skin, as was also demonstrated in previous experimental and clinical trials testing other tissues, while common oral antioxidants had only a minor effect.

Effects of UVB Radiation on the Physicochemical Properties of Fibroblasts and Keratinocytes

The skin is the largest human organ, providing the first line of defense to protect the body from physical and environmental effects. The aim of this study was to determine the influence of short-wave ultraviolet (UVB) radiation on the membrane electrical properties, phospholipid content, and lipid peroxidation levels of fibroblasts and keratinocytes. Changes in cell function may affect the basal electrical surface properties of cell membranes. These changes can be detected using electrokinetic measurements. In this study, the surface charge densities of fibroblasts and keratinocytes were measured as a function of pH. A four-component equilibrium model was used to describe the interaction between the ions in solution and on cell membrane surfaces. Agreement was found between the experimental and theoretical charge variation curves of leukemia cells from pH 2.5 to pH 9. Phospholipid composition was determined qualitatively and quantitatively by HPLC, and lipid peroxidation was estimated by measuring the level of malondialdehyde. The acidic functional group concentrations and average association constants with hydroxyl ions were higher, and the average association constants with hydrogen ions were smaller in UVB-treated skin cell membranes compared to those in untreated cells. Moreover, our results showed that UVB radiation is associated with increased levels of phospholipids and lipid peroxidation products in fibroblasts and keratinocytes.

Longitudinal and retrospective study has demonstrated morphometric variations in the fingerprints of elderly individuals

Dermatoglyphics can be found in the thick skin of both hands and feet which make the identification process possible, however morphological changes throughout life can affect identification in elderly individuals. Considering that dermatoglyphics is an important biometric method, due to it being practical and inexpensive, this longitudinal and retrospective study was aimed to evaluate the morphological variations in fingerprints obtained from men and women (n=20) during their adult and elderly stages of life; the time between obtaining the two fingerprints was 33.5±9.4 years. For the morphometric analysis, an area of 1 cm(2) was selected to quantify the visible friction ridges, minutiae, interpapillary and white lines, and later side-by-side confrontation was used to determine the identity of the individuals. Our results showed a reduction of friction ridges, an increase in the number of white lines for the group (men and women) and a decrease in the number of interpapillary lines in the group of women. It also showed that the selection of compatible fingerprints by the automated AFIS/VRP system allowed the identification of 23 individuals (57.5%), but when the identification was made by the automated AFIS/VRP system, followed by the analysis of archived patterns to eliminate incompatible fingerprints, determination of the identity of 28 individuals (70.0%) was possible. The dermatoglyphics of the elderly suffered morphometric changes that prevented the identification of 30% of them, probably due to the aging process, and pointed to the importance of improving the methods of obtaining fingerprints to clarify issues related to the identification of the elderly.

Anti-wrinkle effects of a tuna heart H2O fraction on Hs27 human fibroblasts

With the increase in life expectancy, there is also growing interest in anti-aging treatments and technologies. The development of anti-aging functional drugs for the skin, and foods from natural sources, may offer solutions to this global matter. Aging involves structural, functional and biochemical changes that occur throughout cells and bodily tissues; the amount of hormones secreted from of all human organs, including the skin, decreases over time. Matrix metalloproteinase (MMP) genes (MMP-1 and -8) play an important role in the aging of skin fibroblasts. For example, an increased MMP expression causes accelerated aging and the degradation of skin elasticity-related genes. In the present study, we examined the anti-wrinkle effects of tuna heart extract which are mediated through the inhibition of MMPs in skin cells. Generally, tuna contains high concentrations of selenium and antioxidants, which serve to remove free radicals, and is known to delay skin and body aging. In addition, unsaturated fatty acids in tuna help to maintain the natural glossy look of skin, and increase skin elasticity, providing moisture for dry skin. A recent study confirmed the various bio-effects of boiled tuna extract and muscle. However, bioactivity studies using tuna heart are limited. Thus, in the present study, we obtained extracts and fractions of tuna heart, and examined their effects on Hs27 human fibroblast proliferation using an MTS assay. In addition, we measured procollagen type 1 levels and elastase activity, and performed β-galactosidase staining. We then measured the expression levels of phosphatidylinositol 3-kinase/Akt and MMP-related genes by western blot analysis and RT-PCR. Our results revealed that tuna heart extract decreased MMP expression by upregulating tissue inhibitors of metallopro-teinase-1 (TIMP-1) and decreasing elastase activity, thus exerting anti-aging and anti-wrinkle effects by increasing collagen synthesis and promoting skin fibroblast proliferation. Thus, our data suggest that tuna heart (TH)-H₂O fractions exert anti-wrinkle effects on Hs27 cells.

Multiple microneedling sessions for minimally invasive facial rejuvenation: an objective assessment

BACKGROUND

Microneedling or percutaneous collagen induction is a new modality used for skin rejuvenation, tightening, and scar remodeling. It offers a simple and effective treatment for photoaged skin with minimal disruption of the epidermis, thus limiting adverse effects and minimizing downtime.

OBJECTIVES

To evaluate the efficacy, coupled with quantitative assessment, of the histological changes in response to multiple sessions of skin microneedling in the treatment of aging skin.

PATIENTS AND METHODS

Ten patients with Fitzpatrick skin type III and IV and Glogau class II to III wrinkles were subjected to six skin microneedling sessions at 2-week intervals. Standard photographs and skin biopsy specimens were obtained at baseline and at one and three months after the start of treatment. Histometry for epidermal thickness and quantitative evaluation of collagen types I, III, and VII, newly synthesized collagen, total elastin, and tropoelastin were performed for all skin biopsies.

RESULTS

Skin microneedling produced noticeable clinical improvement of photoaged skin, with corresponding histological enhancement. Compared to the baseline, collagen types I, III, and VII, as well as newly synthesized collagen, together with tropoelastin showed a statistically significant increase (P < 0.05) in response to treatment, while the mean level of total elastin was significantly decreased (P < 0.05) after treatment.

CONCLUSIONS

Skin microneedling is a promising minimally invasive treatment option with the advantage of increased collagen production. However, multiple sessions are usually needed to maintain the improvement achieved.

Facial skin pores: a multiethnic study

Skin pores (SP), as they are called by laymen, are common and benign features mostly located on the face (nose, cheeks, etc) that generate many aesthetic concerns or complaints. Despite the prevalence of skin pores, related literature is scarce. With the aim of describing the prevalence of skin pores and anatomic features among ethnic groups, a dermatoscopic instrument, using polarized lighting, coupled to a digital camera recorded the major features of skin pores (size, density, coverage) on the cheeks of 2,585 women in different countries and continents. A detection threshold of 250 μm, correlated to clinical scorings by experts, was input into a specific software to further allow for automatic counting of the SP density (N/cm²) and determination of their respective sizes in mm². Integrating both criteria also led to establishing the relative part of the skin surface (as a percentage) that is actually covered by SP on cheeks. The results showed that the values of respective sizes, densities, and skin coverage: 1) were recorded in all studied subjects; 2) varied greatly with ethnicity; 3) plateaued with age in most cases; and 4) globally refected self-assessment by subjects, in particular those who self-declare having “enlarged pores” like Brazilian women. Inversely, Chinese women were clearly distinct from other ethnicities in having very low density and sizes. Analyzing the present results suggests that facial skin pore’s morphology as perceived by human eye less result from functional criteria of associated appendages such as sebaceous glands. To what extent skin pores may be viewed as additional criteria of a photo-altered skin is an issue to be further addressed.

Growth hormone-releasing peptide-biotin conjugate stimulates myocytes differentiation through insulin-like growth factor-1 and collagen type I

Based on the potential beneficial effects of growth hormone releasing peptide (GHRP)-6 on muscle functions, a newly synthesized GHRP-6-biotin conjugate was tested on cultured myoblast cells. Increased expression of myogenic marker proteins was observed in GHRP-6-biotin conjugate-treated cells. Additionally, increased expression levels of insulin-like growth factor-1 and collagen type I were observed. Furthermore, GHRP-6-biotin conjugate-treated cells showed increased metabolic activity, as indicated by increased concentrations of energy metabolites, such as ATP and lactate, and increased enzymatic activity of lactate dehydrogenase and creatine kinase. Finally, binding protein analysis suggested few candidate proteins, including desmin, actin, and zinc finger protein 691 as potential targets for GHRP6-biotin conjugate action. These results suggest that the newly synthesized GHRP-6-biotin conjugate has myogenic stimulating activity through, at least in part, by stimulating collagen type I synthesis and several key proteins. Practical applications of the GHRP-6-biotin conjugate could include improving muscle condition. [BMB Reports 2015; 48(9): 501-506]

Expression of transforming growth factor-β after different non-invasive facial rejuvenation modalities

BACKGROUND

Transforming growth factor-β (TGF-β) is a major regulator of the synthesis of extracellular matrix (ECM) proteins in human skin as it stimulates fibroblast proliferation and collagen production. Perturbed TGF-β expression may play a key role in the pathogenesis of skin aging.

OBJECTIVES

This study was conducted to objectively evaluate the effects of different modalities of non-invasive facial rejuvenation on TGF-β expression and to correlate its level with that of newly synthesized collagen.

METHODS

A total of 36 patients with Fitzpatrick skin types III and IV were divided into six groups. Each group of six patients was subjected to a different non-invasive modality for the treatment of skin aging, including radiofrequency (RF), Nd:YAG 1320-nm laser and Er:YAG 2940-nm laser mini-peels, intense pulsed light (IPL), mesotherapy injection, and electro-optical synergy (ELOS). Skin biopsies were obtained before treatment, at the end of treatment, and at three months post-treatment. In addition, biopsies were obtained from 30 control subjects. Levels of TGF-β were quantitatively evaluated using computerized image analysis of immunostained sections.

RESULTS

The expression of TGF-β was statistically significantly increased (P < 0.05) at the end of Nd:YAG 1320-nm and Er:YAG 2940-nm mini-peel treatments compared with baseline levels, and at three months post-treatment with RF and ELOS compared with pretreatment and end-of-treatment levels. However, no significant differences (P > 0.05) were observed in TGF-β level in response to IPL or mesotherapy treatments in comparison with baseline. The level of TGF-β was positively correlated (P < 0.05) to that of newly synthesized collagen at the end of Nd:YAG 1320-nm laser and Er:YAG 2940-nm laser mini-peels, as well as at three months after RF and ELOS treatments.

CONCLUSIONS

Radiofrequency, ELOS, and Nd:YAG 1320-nm laser and Er:YAG 2940-nm laser mini-peels resulted in an increase in TGF-β expression, which may mediate the effects of these modalities in enhancing dermal collagen expression through the activation of fibroblasts and thereby reverse the photoaging of skin.

Acne tarda and male-pattern baldness unmasking primary ovarian insufficiency: a case and review

A 30-year-old woman presented with recurrent acne lesions and progressing male-pattern baldness. Furthermore, she reported amenorrhea, weight loss, mucosal xerosis and dyspareunia since discontinuation of hormonal contraception 6 months earlier in order to conceive. Acne tarda and androgenetic alopecia of female pattern were diagnosed. Hormonal and immunologic serological and ultrasound examinations revealed an autoimmune hypergonadotropic primary ovarian insufficiency (POI) with no ovarian cysts but ovarian fibrosis with marked reduced follicle pool. Immediate ovarian stimulation and in vitro fertilization led to pregnancy and the patient gave birth to a healthy child. Though presenting with clinical findings similar to menopause, 50% of patients with POI exhibit varying and unpredictable ovarian function, and only 5-10% are able to accomplish pregnancy. Genetic disorders affect the X chromosome. In 14-30% of cases POI has been associated with autoimmunity. POI may occur after discontinuation of hormonal contraception, like in our case.

p53 Induces skin aging by depleting Blimp1+ sebaceous gland cells

p53 is an important inducer of organismal aging. However, its roles in the aging of skin remain unclear. Here we show that mice with chronic activation of p53 develop an aging phenotype in the skin associated with a reduction of subcutaneous fat and loss of sebaceous gland (SG). The reduction in the fat layer may result from the decrease of mammalian TOR complex 1 (mTORC1) activity accompanied by elevated expression of energy expenditure genes, and possibly as compensatory effects, leading to the elevation of peroxisome proliferator-activated receptor (PPAR)γ, an inducer of sebocyte differentiation. In addition, Blimp1(+) sebocytes become depleted concomitantly with an increase in cellular senescence, which can be reversed by PPARγ antagonist (BADGE) treatment. Therefore, our results indicate that p53-mediated aging of the skin involves not only thinning through the loss of subdermal fat, but also xerosis or drying of the skin through declining sebaceous gland activity.

Genetics and skin aging

Skin aging is a complex process and underlies multiple influences with the probable involvement of heritable and various environmental factors. Several theories have been conducted regarding the pathomechanisms of aged skin, however fundamental mechanisms still remain poorly understood. This article addresses the influence of genetics on skin aging and in particular deals with the differences observed in ethnic populations and between both genders. Recent studies indicate that male and female aged skin differs as far as the type, the consistency and the sensitivity to external factors is concerned. The same has been also documented between elderly people of different origin. Consequently, the aging process taking place in both genders and in diverse ethnic groups should be examined separately and products specialized to each population should be developed in order to satisfy the special needs.

Expression of p53 protein after nonablative rejuvenation: the other side of the coin

BACKGROUND

Disturbance of p53 expression may play an important role in the pathogenesis of ultraviolet (UV) light-induced skin cancer as well as photoaging.

OBJECTIVES

To objectively evaluate the potential effect of nonablative facial rejuvenation on p53 expression.

PARTICIPANTS AND METHODS

Thirty patients with Fitzpatrick skin type III to IV were divided into five groups. Each group underwent a different nonablative modality: radiofrequency (RF), intense pulsed light (IPL), electro-optical synergy (ELOS) (combined RF and IPL), 1,320-nm neodymium-doped yttrium aluminum garnet (Nd:YAG) laser, and 2,940-nm erbium-doped (Er):YAG laser minipeel. Skin biopsies were obtained before treatment, by the end of treatment, and 3 months after treatment. Biopsies were also taken from 30 controls. Quantitative evaluation of p53 was performed using computer image analysis for immunostained tissues.

RESULTS

P53 expression was statistically significantly greater at the end of IPL (p = .02) and ELOS (p = .02) treatments than before treatment but was statistically insignificantly lower (p > .05) 3 months after treatment than at the end of treatment. No significant differences (p > .05) were observed in p53 level after RF, 1,320-nm Nd:YAG, and 2,940-nm Er:YAG mini-peel treatments from baseline.

CONCLUSIONS

The increase in epidermal p53 expression after IPL treatment could increase the risk of skin neoplasia by intense pulsed light-induced DNA damage which may lead to dysregulation of apoptosis and initiation of skin cancer.

Identification of epigenetically altered genes in sporadic amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a terminal disease involving the progressive degeneration of motor neurons within the motor cortex, brainstem and spinal cord. Most cases are sporadic (sALS) with unknown causes suggesting that the etiology of sALS may not be limited to the genotype of patients, but may be influenced by exposure to environmental factors. Alterations in epigenetic modifications are likely to play a role in disease onset and progression in ALS, as aberrant epigenetic patterns may be acquired throughout life. The aim of this study was to identify epigenetic marks associated with sALS. We hypothesize that epigenetic modifications may alter the expression of pathogenesis-related genes leading to the onset and progression of sALS. Using ELISA assays, we observed alterations in global methylation (5 mC) and hydroxymethylation (5 HmC) in postmortem sALS spinal cord but not in whole blood. Loci-specific differentially methylated and expressed genes in sALS spinal cord were identified by genome-wide 5mC and expression profiling using high-throughput microarrays. Concordant direction, hyper- or hypo-5mC with parallel changes in gene expression (under- or over-expression), was observed in 112 genes highly associated with biological functions related to immune and inflammation response. Furthermore, literature-based analysis identified potential associations among the epigenes. Integration of methylomics and transcriptomics data successfully revealed methylation changes in sALS spinal cord. This study represents an initial identification of epigenetic regulatory mechanisms in sALS which may improve our understanding of sALS pathogenesis for the identification of biomarkers and new therapeutic targets.

Identification of biomarkers of human skin ageing in both genders. Wnt signalling - a label of skin ageing?

The goal of our work has been to investigate the mechanisms of gender-independent human skin ageing and examine the hypothesis of skin being an adequate model of global ageing. For this purpose, whole genome gene profiling was employed in sun-protected skin obtained from European Caucasian young and elderly females (mean age 26.7±4 years [n1 = 7] and 70.75±3.3 years [n2 = 4], respectively) and males (mean age 25.8±5.2 years [n3 = 6] and 76±3.8 years [n4 = 7], respectively) using the Illumina array platform. Confirmation of gene regulation was performed by real-time RT-PCR and immunohistochemistry. 523 genes were significantly regulated in female skin and 401 genes in male skin for the chosen criteria. Of these, 183 genes exhibited increased and 340 decreased expression in females whereas 210 genes showed increased and 191 decreased expression in males with age. In total, 39 genes were common in the target lists of significant regulated genes in males and females. 35 of these genes showed increased (16) or decreased (19) expression independent of gender. Only 4 overlapping genes (OR52N2, F6FR1OP2, TUBAL3 and STK40) showed differential regulation with age. Interestingly, Wnt signalling pathway showed to be significantly downregulated in aged skin with decreased gene and protein expression for males and females, accordingly. In addition, several genes involved in central nervous system (CNS) ageing (f.i. APP, TAU) showed to be expressed in human skin and were significanlty regulated with age. In conclusion, our study provides biomarkers of endogenous human skin ageing in both genders and highlight the role of Wnt signalling in this process. Furthermore, our data give evidence that skin could be used as a good alternative to understand ageing of different tissues such as CNS.

High-resolution ultrasound imaging of human skin in vivo by using three-dimensional ultrasound microscopy

Observing the morphology of human skin is important in the diagnosis of skin cancer and inflammation and in the assessment of skin aging. High-frequency ultrasound imaging provides high spatial resolution of the deep layers of the skin, which cannot be visualized by optical methods. The objectives of the present study were to develop a three-dimensional (3-D) ultrasound microscope and to observe the morphology of normal human skin in vivo. A concave polyvinylidene fluoride transducer with a central frequency of 120 MHz was excited using an electric pulse generated by semiconductor switching. The transducer was scanned two-dimensionally by using two linear motors on the region-of-interest and the ultrasonic reflection was digitized with 2-GHz sampling. Consecutive B-mode images perpendicular to the skin surface were reconstructed to generate multiplanar reconstructed images and 3-D volume-rendering images clearly showing microstructures such as sebaceous glands and hair follicles. The 3-D ultrasound microscope could be used to successfully image the morphology of human skin noninvasively and may provide important information on skin structure.

Discovering the link between nutrition and skin aging

Skin has been reported to reflect the general inner-health status and aging. Nutrition and its reflection on skin has always been an interesting topic for scientists and physicians throughout the centuries worldwide. Vitamins, carotenoids, tocopherols, flavonoids and a variety of plant extracts have been reported to possess potent anti-oxidant properties and have been widely used in the skin care industry either as topically applied agents or oral supplements in an attempt to prolong youthful skin appearance. This review will provide an overview of the current literature "linking" nutrition with skin aging.

Hormonal therapy of intrinsic aging

Intrinsic skin aging represents the biological clock of the skin cells per se and reflects the reduction processes that are common in internal organs. The reduced secretion of the pituitary, adrenal glands, and the gonads contributes to characteristic aging-associated body and skin phenotypes as well as behavior patterns. Our knowledge of whether there is a direct or indirect connection between hormonal deficiency and skin aging still remains limited. In females, serum levels of 17β-estradiol, dehydroepiandrosterone, progesterone, growth hormone (GH), and its downstream hormone insulin-like growth factor I (IGF-I) are significantly decreased with increasing age. In males, serum levels of GH and IGF-I decrease significantly, whereas it can decrease in late age in a part of the population. Hormones have been shown to influence skin morphology and functions, skin permeability, wound healing, sebaceous lipogenesis, and the metabolism of skin cells. Prevention of skin aging by estrogen/progesterone replacement therapy is effective if administered early after menopause and influences intrinsically aged skin only. Vitamin D substitution and antioxidant treatment may also be beneficial. Replacement therapy with androgens, GH, IGF-I, progesterone, melatonin, cortisol, and thyroid hormones still remains controversial.

Hormones and the pilosebaceous unit

Hormones can exert their actions through endocrine, paracrine, juxtacrine, autocrine and intracrine pathways. The skin, especially the pilosebaceous unit, can be regarded as an endocrine organ meanwhile a target of hormones, because it synthesizes miscellaneous hormones and expresses diverse hormone receptors. Over the past decade, steroid hormones, phospholipid hormones, retinoids and nuclear receptor ligands as well as the so-called stress hormones have been demonstrated to play pivotal roles in controlling the development of pilosebaceous units, lipogenesis of sebaceous glands and hair cycling. Among them, androgen is most extensively studied and of highest clinical significance. Androgen-mediated dermatoses such as acne, androgenetic alopecia and seborrhea are among the most common skin disorders, with most patients exhibiting normal circulating androgen levels. The "cutaneous hyperandrogenism" is caused by in stiu overexpression of the androgenic enzymes and hyperresponsiveness of androgen receptors. Regulation of cutaneous steroidogenesis is analogous to that in gonads and adrenals. More work is needed to explain the regional difference within and between the androgn-mediated dermatoses. The pilosebaceous unit can act as an ideal model for studies in dermato-endocrinology.

Sebaceous gland receptors

Receptors are proteins, embedded in a cell or cytoplasmic membrane, to which a mobile signaling molecule may attach. Receptor ligands may be peptides (such as neurotransmitters), hormones, pharmaceutical drugs and/or a toxins, whereas "binding" ordinarily initiates a cellular response. Human sebocytes are biologically and metabolically very active cells and consequently express numerous receptors. Three of four groups of peptide/neurotransmitter receptors, the so-called serpentine receptor group are present (corticotropin-releasing hormone receptors 1 and 2, melanocortin-1 and 5 receptors, mu-opiate receptors, VPAC receptors, cannabinoid receptors 1 and 2, vascular endothelial growth factor receptor and histamine 1 receptor). The single-transmembrane domain receptors are represented by the insulin-like growth factor-I receptor and the third group, which does not possess intrinsic tyrosine kinase activity, by the growth factor receptor. Nuclear receptors expressed in sebocytes are grouped into two major subtypes. From the steroid receptor family, the androgen receptor and the progesterone receptor are expressed. The thyroid receptor family includes the estrogen receptors (alpha and beta isotypes), the retinoic acid receptors (isotypes alpha and gamma) and retinoid X receptors (isotypes alpha, beta, gamma), the vitamin D receptor, the peroxisome proliferator-activated receptors (isotypes alpha, delta and gamma) and the liver X receptors (alpha and beta isotypes). The vanilloid receptor belongs to the transient ion channels and is expressed in differentiating human sebocytes. Further sebocyte receptors, which may influence their function are fibroblast growth factor receptor 2, epidermal growth factor receptor, c-MET, CD14, Toll-like receptor 2, Toll-like receptor 4 and Toll-like receptor 6. Receptor-ligand interactions control sebocyte proliferation, differentiation and lipid synthesis. However, not every ligand that binds to a sebocyte receptor also activates it, such ligands are receptor antagonists and inverse agonists.

[Molecular etiology of skin aging. How important is the genetic make-up?]

Although the fundamental mechanisms in the pathogenesis of skin aging are still poorly understood, a growing body of evidence points toward the involvement of multiple pathways. Recent data obtained by expression profiling studies and studies upon progeroid syndromes illustrate that among the most important biological processes involved in skin aging are alterations in DNA repair and stability, mitochondrial function, cell cycle and apoptosis, extracellular matrix, lipid synthesis, ubiquitin-induced proteolysis and cellular metabolism. One of the major factors which have been proposed to play an exquisite role in the initiation of aging is the physiological decline of hormones occurring with age. However, hormones at age-specific levels may not only regulate age-associated mechanisms but also modulate tumor suppressor pathways that influence carcinogenesis. In conclusion, understanding the molecular mechanisms of ageing may open new strategies to deal with the various diseases accompanying advanced age including cancer.

Clinical aspects and molecular diagnostics of skin aging

This contribution will address the effect of aging on skin functions, with a particular focus on skin permeability, wound healing, angiogenesis, lipogenesis, sweat production, immune function, and vitamin D synthesis. With accelerating age, skin functions deteriorate due to structural and morphologic changes. Skin is prone to the development of several diseases, varying from benign to malignant. Because the number of persons aged 80 and older is expected to rise in the next decades, disease prevention will become an important issue. Screening examinations and prevention through public education starting at an early age regarding sun avoidance, the use of sunscreens and the importance of a balanced nutrition are the first steps for successful healthy aging. Although the fundamental mechanisms in the pathogenesis of aged skin are still poorly understood, a growing body of evidence points toward the involvement of multiple pathways. Recent data obtained by expression profiling studies and studies of progeroid syndromes illustrate that among the most important biologic processes involved in skin aging are alterations in DNA repair and stability, mitochondrial function, cell cycle and apoptosis, extracellular matrix, lipid synthesis, ubiquitin-induced proteolysis and cellular metabolism. Among others, a major factor that has been implicated in the initiation of aging is the physiologic decline of hormones occurring with age. However, hormones at age-specific levels may regulate not only age-associated mechanisms but also tumor suppressor pathways that influence carcinogenesis. Understanding the molecular mechanisms of aging may open new strategies to deal with the various diseases accompanying high age, including cancer.

Molecular mechanisms and in vivo mouse models of skin aging associated with dermal matrix alterations

Skin is the most superficial body organ and plays an important role in protecting the body from environmental damage and in forming social relations. With the increase of the aging population in our society, dermatological and cosmetic concerns of skin aging are rapidly increasing. Skin aging is a complex process combined with intrinsic and extrinsic factors. Intrinsic or chronological skin aging results from the passage of time and is influenced by genetic factors. Extrinsic skin aging is mainly determined by UV irradiation, also called photoaging. These two types of aging processes are superimposed on sun-exposed skin, and have a common feature of causing dermal matrix alterations that mostly contribute to the formation of wrinkles, laxity, and fragility of aged skin. The dermal matrix contains extracellular matrix proteins such as collagen, elastin, and proteoglycans that confer the strength and resiliency of skin. Skin aging associated with dermal matrix alterations and atrophy can be caused by cellular senescence of dermal cells like fibroblasts, and decreased synthesis and accelerated degradation of dermal matrix components, especially collagen fibers. Both intrinsic aging and photoaging exert influence during each step of dermal matrix alteration via different mechanisms. Mouse models of skin aging have been extensively developed to elucidate intrinsic aging and photoaging processes, to validate in vitro biochemical data, and to test the effects of pharmacological tools for retarding skin aging because they have the advantages of being genetically similar to humans and are easily available.

In vitro permeation and in vivo anti-inflammatory and analgesic properties of nanoscaled emulsions containing ibuprofen for topical delivery

INTRODUCTION

As a topical delivery system, a nanoscaled emulsion is considered a good carrier of several active ingredients that convey several side effects upon oral administration, such as nonsteroidal anti-inflammatory drugs (NSAIDs).

OBJECTIVE

We investigated the in vitro permeation properties and the in vivo pharmacodynamic activities of different nanoscaled emulsions containing ibuprofen, an NSAID, as an active ingredient and newly synthesized palm olein esters (POEs) as the oil phase.

METHODOLOGY

A ratio of 25:37:38 of oil phase:aqueous phase:surfactant was used, and different additives were used for the production of a range of nanoscaled emulsions. Carbopol® 940 dispersion neutralized by triethanolamine was employed as a rheology modifier. In some circumstances, menthol and limonene were employed at different concentrations as permeation promoters. All formulae were assessed in vitro using Franz diffusion cell fitted with full-thickness rat skin. This was followed by in vivo evaluation of the anti-inflammatory and analgesic activities of the promising formulae and comparison of the effects with that of the commercially available gel.

RESULTS AND DISCUSSION

Among all other formulae, formula G40 (Carbopol® 940-free formula) had a superior ability in transferring ibuprofen topically compared with the reference. Carbopol® 940 significantly decreased the amount of drug transferred from formula G41 through the skin as a result of swelling, gel formation, and reduction in drug thermodynamic activity. Nonetheless, the addition of 10% w/w of menthol and limonene successfully overcame this drawback since, relative to the reference, higher amount of ibuprofen was transferred through the skin. By contrast, these results were relatively comparable to that of formula G40. Pharmacodynamically, the G40, G45, and G47 formulae exhibited the highest anti-inflammatory and analgesic effects compared with other formulae.

CONCLUSION

The ingredients and the physical properties of the nanoscaled emulsions produced by using the newly synthesized POEs succeeded to deliver ibuprofen competently.

[Dermatoendocrinology. Skin aging]

Hormones and their imbalances have significant effects on the morphology and physiology of the skin and influence various skin functions, especially wound healing and lipogenesis. With increasing age, the concentrations of important circulating hormones, including growth hormone and sex-related steroids, decrease continuously. As a result, physiologic processes are negatively influenced and various age-associated disorders may develop. As the population aged 80 and over is expected to rise in the next decades, the understanding of the molecular mechanisms accompanying skin aging and disease prevention will become even more important and play a role in preventing disease.

The elderly as a sensitive population in environmental exposures: making the case

The US population is aging. CDC has estimated that 20% of all Americans will be 65 or older by the year 2030. As a part of the aging process, the body gradually deteriorates and physiologic and metabolic limitations arise. Changes that occur in organ anatomy and function present challenges for dealing with environmental stressors of all kinds, ranging from temperature regulation to drug metabolism and excretion. The elderly are not just older adults, but rather are individuals with unique challenges and different medical needs than younger adults. The ability of the body to respond to physiological challenge presented by environmental chemicals is dependent upon the health of the organ systems that eliminate those substances from the body. Any compromise in the function of those organ systems may result in a decrease in the body's ability to protect itself from the adverse effects of xenobiotics. To investigate this issue, we performed an organ system-by-organ system review of the effects of human aging and the implications for such aging on susceptibility to drugs and xenobiotics. Birnbaum (1991) reported almost 20 years ago that it was clear that the pharmacokinetic behavior of environmental chemicals is, in many cases, altered during aging. Yet, to date, there is a paucity of data regarding recorded effects of environmental chemicals on elderly individuals. As a result, we have to rely on what is known about the effects of aging and the existing data regarding the metabolism, excretion, and adverse effects of prescription medications in that population to determine whether the elderly might be at greater risk when exposed to environmental substances. With increasing life expectancy, more and more people will confront the problems associated with advancing years. Moreover, although proper diet and exercise may lessen the immediate severity of some aspects of aging, the process will continue to gradually degrade the ability to cope with a variety of injuries and diseases. Thus, the adverse effects of long-term, low-level exposure to environmental substances will have a longer time to be manifested in a physiologically weakened elderly population. When such exposures are coupled with concurrent exposure to prescription medications, the effects could be devastating. Public health officials must be knowledgeable about the sensitivity of the growing elderly population, and ensure that the use of health guidance values (HGVs) for environmental contaminants and other substances give consideration to this physiologically compromised segment of the population.