[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.

Free Fatty Acids Induce Lipid Accumulation, Autophagy, and Apoptosis in Human Sebocytes

BACKGROUND

A disruption of sebocyte differentiation and lipogenesis has fatal consequences and can cause a wide spectrum of skin diseases, from acne vulgaris to sebaceous carcinoma, however, the relevant molecular mechanisms have not been fully clarified.

OBJECTIVES

The induction of autophagy and apoptosis in human sebocytes in response to biologically relevant fatty acids was investigated.

METHODS

Free fatty acids (arachidonic acid, linoleic acid, palmitic acid, and palmitoleic acid) and the pan-caspase inhibitor QVD-Oph were added to the supernatant of cultured human SZ95 sebocytes. Individual relevant proteins were analyzed by Western blotting. Apoptosis and cell viability were determined, and typical autophagy structures were detected through electron microscopy. To obtain cell growth curves, cell confluence was continuously monitored by real-time cell analysis.

RESULTS

Fatty acids induced the development of intracellular lipid droplets with subsequent apoptosis, whereas arachidonic acid caused the most rapid effect. Cleavage products of caspase-3 were only detected in arachidonic acid-induced apoptosis. The high basal apoptotic rate of cultured SZ95 sebocytes was strongly suppressed by QVD-Oph. Fatty acid-induced apoptosis was also markedly inhibited by QVD-Oph, whereas intracellular lipid droplets further accumulated. While cell viability after incubation with linoleic acid, palmitic acid, or palmitoleic acid and QVD-Oph was comparable with that of non-treated controls, arachidonic acid significantly reduced cell viability and cell density despite the concomitant pan-caspase inhibitor treatment. Using electron microscopy, typical autophagy structures were detected, such as autophagosomes and autolysosomes, at the basal level, which became more pronounced after treatment with fatty acids.

CONCLUSIONS

Our findings contribute to a better understanding of the inflammation-associated mechanisms of lipogenesis and cell death induction in human sebocytes and may help to unveil the effects of fatty acid-rich human nutrition.

Inflammation and thrombo-occlusive vessel signalling in benign atrophic papulosis (Köhlmeier-Degos disease)

BACKGROUND

Although the merely cutaneous, benign form of the extremely rare disease atrophic papulosis (Köhlmeier-Degos disease) may occasionally develop into the systemic, malignant form with time, it is unclear whether it itself exhibits any systemic characteristics.

OBJECTIVE

To determine whether benign atrophic papulosis exhibits inflammatory and thrombo-occlusive signals and to classify it according to the Chapel-Hill classification of vasculitis.

METHODS

In a monocentric, controlled study, levels of cytokines (IL-1β, IL-6, IL-8, IFNγ, MCP-1, VEGF, TNFα, TGF-β1), antiphospholipid antibodies (cardiolipin IgG/A/M, cardiolipin IgG, cardiolipin IgM, β2-glycoprotein IgG/A/M, phosphatidyl choline, phosphatidyl serine, phosphatidyl inositol, phosphatidyl ethanolamine and sphingomyelin A), antibodies against proteinase-3 IgG and myeloperoxidase IgG, antinuclear antibodies and extractable nuclear antigen were assessed in blood samples of six benign atrophic papulosis patients and six age- and sex-matched healthy controls.

RESULTS

IL-8 was only detectable in patients' serum. VEGF was reduced and cardiolipin IgG/A/M and β2-glycoprotein antibodies were increased in the patients' group. ANA were only detected in three patients, ENA were throughout negative. No differences were detected between the other investigated markers.

CONCLUSIONS

This is the first study evaluating systemic inflammatory and thrombo-occlusive vessel signalling in benign atrophic papulosis and provide evidence of a non-antineutrophil cytoplasmatic antibodies immune-complex small vessel vasculitis according to the Chapel-Hill classification. These findings corroborate its systemic character despite the apparent missing involvement of systemic organs.

Involvement of Pattern Recognition Receptors in the Direct Influence of Bacterial Components and Standard Antiacne Compounds on Human Sebaceous Gland Cells

INTRODUCTION

Pattern recognition receptors are involved in innate and adaptive immunity by detecting microbial components. Bacteria have been accused to play a role in inflammatory acne. We investigated the potential involvement of Toll-like receptor (TLR)2, TLR4, TLR6, and CD14 in the direct influence of bacterial components and standard antiacne compounds on human sebocytes.

METHODS

mRNA and protein expression of TLR2, TLR4, TLR6, and CD14 in SZ95 sebocytes was evaluated by real-time qRT-PCR and immunocytochemistry. The effects of lipopolysaccharides (LPS) and lipoteichoic acid on TLR2, TLR4, and CD14 expression and of cytokine/chemokine secretion by 13-cis-retinoic acid, all-trans-retinoic acid, retinol, and hydrocortisone at the mRNA and protein levels were assessed by real-time qRT-PCR and ELISA and verified by cocultivation with neutralizing antibodies.

RESULTS

The constitutive expression of TLR2, TLR4, and CD14 in SZ95 sebocytes was augmented by exposure to LPS. Hydrocortisone induced TLR2, but markedly reduced TLR4 expression. 13-cis-retinoic acid and all-trans-retinoic acid regulated IL-6 release. LPS enhanced and hydrocortisone reduced cytokine and chemokine release. Anti-TLR4 and anti-CD14 mAb blocked LPS-induced IL-8 and IL-6 release.

CONCLUSIONS

Microbial components use pattern recognition receptors to directly activate sebocytes to express a wide range of proinflammatory molecules and especially IL-8 and IL-6 in a TLR4- and CD14-specific manner. Retinoids, but mostly corticosteroids, also use this pathway to exhibit anti-inflammatory effects.

MSCs rescue impaired wound healing in a murine LAD1 model by adaptive responses to low TGF-β1 levels

Mutations in the CD18 gene encoding the common β-chain of β2 integrins result in impaired wound healing in humans and mice suffering from leukocyte adhesion deficiency syndrome type 1 (LAD1). Transplantation of adipose tissue-derived mesenchymal stem cells (MSCs) restores normal healing of CD18^-/- wounds by restoring the decreased TGF-β1 concentrations. TGF-β1 released from MSCs leads to enhanced myofibroblast differentiation, wound contraction, and vessel formation. We uncover that MSCs are equipped with a sensing mechanism for TGF-β1 concentrations at wound sites. Low TGF-β1 concentrations as occurring in CD18^-/- wounds induce TGF-β1 release from MSCs, whereas high TGF-β1 concentrations suppress TGF-β1 production. This regulation depends on TGF-β receptor sensing and is relayed to microRNA-21 (miR-21), which subsequently suppresses the translation of Smad7, the negative regulator of TGF-β1 signaling. Inactivation of TGF-β receptor, or overexpression or silencing of miR-21 or Smad7, abrogates TGF-β1 sensing, and thus prevents the adaptive MSC responses required for tissue repair.

Alterations in innate immunity and epithelial cell differentiation are the molecular pillars of hidradenitis suppurativa

BACKGROUND

The large unmet need of hidradenitis suppurativa/acne inversa (HS) therapy requires the elucidation of disease-driving mechanisms and tissue targeting.

OBJECTIVE

Robust characterization of the underlying HS mechanisms and detection of the involved skin compartments.

METHODS

Hidradenitis suppurativa/acne inversa molecular taxonomy and key signalling pathways were studied by whole transcriptome profiling. Dysregulated genes were detected by comparing lesional and non-lesional skin obtained from female HS patients and matched healthy controls using the Agilent array platform. The differential gene expression was confirmed by quantitative real-time PCR and targeted protein characterization via immunohistochemistry in another set of female patients. HS-involved skin compartments were also recognized by immunohistochemistry.

RESULTS

Alterations to key regulatory pathways involving glucocorticoid receptor, atherosclerosis, HIF1α and IL17A signalling as well as inhibition of matrix metalloproteases were detected. From a functional standpoint, cellular assembly, maintenance and movement, haematological system development and function, immune cell trafficking and antimicrobial response were key processes probably being affected in HS. Sixteen genes were found to characterize HS from a molecular standpoint (DEFB4, MMP1, GJB2, PI3, KRT16, MMP9, SERPINB4, SERPINB3, SPRR3, S100A8, S100A9, S100A12, S100A7A (15), KRT6A, TCN1, TMPRSS11D). Among the proteins strongly expressed in HS, calgranulin-A, calgranulin-B and serpin-B4 were detected in the hair root sheath, koebnerisin and connexin-32 in stratum granulosum, transcobalamin-1 in stratum spinosum/hair root sheath, small prolin-rich protein-3 in apocrine sweat gland ducts/sebaceous glands-ducts and matrix metallopeptidase-9 in resident monocytes.

CONCLUSION

Our findings highlight a panel of immune-related drivers in HS, which influence innate immunity and cell differentiation in follicular and epidermal keratinocytes as well as skin glands.

2A-DUB/Mysm1 Regulates Epidermal Development in Part by Suppressing p53-Mediated Programs

Development and homeostasis of the epidermis are governed by a complex network of sequence-specific transcription factors and epigenetic modifiers cooperatively regulating the subtle balance of progenitor cell self-renewal and terminal differentiation. To investigate the role of histone H2A deubiquitinase 2A-DUB/Mysm1 in the skin, we systematically analyzed expression, developmental functions, and potential interactions of this epigenetic regulator using Mysm1-deficient mice and skin-derived epidermal cells. Morphologically, skin of newborn and young adult Mysm1-deficient mice was atrophic with reduced thickness and cellularity of epidermis, dermis, and subcutis, in context with altered barrier function. Skin atrophy correlated with reduced proliferation rates in Mysm1^-/- epidermis and hair follicles, and increased apoptosis compared with wild-type controls, along with increases in DNA-damage marker γH2AX. In accordance with diminished α6-Integrin^high+CD34⁺ epidermal stem cells, reduced colony formation of Mysm1^-/- epidermal progenitors was detectable in vitro. On the molecular level, we identified p53 as potential mediator of the defective Mysm1-deficient epidermal compartment, resulting in increased pro-apoptotic and anti-proliferative gene expression. In Mysm1^-/-p53^-/- double-deficient mice, significant recovery of skin atrophy was observed. Functional properties of Mysm1^-/- developing epidermis were assessed by quantifying the transepidermal water loss. In summary, this investigation uncovers a role for 2A-DUB/Mysm1 in suppression of p53-mediated inhibitory programs during epidermal development.

Pathogenesis of wound healing disorders in the elderly

The elderly constitute the age group most susceptible to wound healing disorders and chronic wounds, the most prevalent being venous leg ulcers, pressure ulcers, and diabetic foot ulcers. However, other age-associated diseases should also be taken into consideration in the diagnostic workup of chronic wounds, and not be underestimated. A better understanding of the pathomechanisms involved in the wound healing process is of key importance in combatting the difficulties associated with the treatment of chronic wounds. In recent decades, considerable progress has been made in the development of pioneering therapeutic strategies for chronic wounds. In this context, the use of growth factors and cytokines, tissue engineering, and cell therapy - including stem cells - have proven very promising. Nevertheless, prior to their introduction into routine clinical practice, large controlled clinical trials are required to assess the safety of these techniques.

Professional caregivers' knowledge in dermatology : Improving knowledge and communication to dermatologists in geriatric facilities

BACKGROUND

Research regarding effective collaboration and communication between professional caregivers and dermatologists and the need for further education and training for caregivers in the field of geriatric dermatology still remains relatively scarce.

OBJECTIVE

To document the state of knowledge of professional caregivers in the field of geriatric dermatology and make recommendations for dermatological education and postgraduate training.

METHODS

A questionnaire with open and closed questions was used to evaluate the level of knowledge and current need for information in geriatric dermatology. A total of 58 professional caregivers from several hospital departments, including geriatric wards and nursing homes participated in this study. Quantitative and qualitative data were generated and responses to open questions were categorized according to the most quoted contents. The study was approved by the Charité University in Berlin ethics committee.

RESULTS

The study demonstrates that there is a lack of dermatological knowledge. Participants indicated a huge information need regarding skin tumors (77.2 %), prevention of skin diseases (50.0 %) and pruritus (41.4 %). According to the caregivers, communication problems with physicians arise in view of using standardized terms of skin diseases (22.9 %) and formulating unclear care records of skin diseases (20.8 %).

CONCLUSION

Difficulties in communication between professional caregivers and physicians can influence patients' punctual and well-founded treatment; therefore, further education must be mediated vividly and practically. Moreover, training should focus on learning standardized terms and descriptions for optimizing the flow of information with physicians and written communication, such as care records.

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.

Diabetes mellitus and the skin

Diabetes is a debilitating, life-threatening disease accounting in 2015 for the death of 5 million people worldwide. According to new estimations, 415 million adults currently suffer from the disease, and this number is expected to rise to 642 million by 2040. High glucose blood levels also affect the skin among systemic organs, and skin disorders can often predict the onset of this metabolic disorder. In this review, we address the pathomechanistic effects of diabetes on the skin and give an overview on the most common skin diseases associated with diabetes.

Marked Reduction of the Number and Individual Volume of Sebaceous Glands in Psoriatic Lesions

BACKGROUND

Psoriasis is a chronic inflammatory skin disease characterized by plaques with inflammation, infiltration, hyper-/parakeratosis and desquamation. Microscopic findings in previous studies have revealed some degree of atrophy of the sebaceous glands in patients with psoriasis vulgaris and psoriatic alopecia.

OBJECTIVE

The aim of this study was to investigate possible changes of the sebaceous glands in patients with psoriatic plaques and especially psoriatic alopecia.

METHODS

Histological and stereological analyses were performed in skin specimens from involved and healthy-looking skin of 14 patients with psoriasis. Stereology detects and quantifies 3-dimensional structures ex vivo. Furthermore, the differentiation process of sebocytes of another 14 psoriatic patients was examined by immunohistochemistry of involved and uninvolved skin specimens.

RESULTS

A significant reduction of the number of sebaceous glands as well as of the volume of individual sebaceous glands was assessed in the lesional compared to the nonlesional psoriatic skin. Moreover, it was likely that sebocytes in psoriatic lesions may not differentiate properly.

CONCLUSION

These findings indicate that the sebaceous gland may be a player and not an innocent bystander in the development of psoriatic lesions and especially of psoriatic alopecia.

PI3K/AKT Signaling Pathway Is Essential for Survival of Induced Pluripotent Stem Cells

Apoptosis is a highly conserved biochemical mechanism which is tightly controlled in cells. It contributes to maintenance of tissue homeostasis and normally eliminates highly proliferative cells with malignant properties. Induced pluripotent stem cells (iPSCs) have recently been described with significant functional and morphological similarities to embryonic stem cells. Human iPSCs are of great hope for regenerative medicine due to their broad potential to differentiate into specialized cell types in culture. They may be useful for exploring disease mechanisms and may provide the basis for future cell-based replacement therapies. However, there is only poor insight into iPSCs cell signaling as the regulation of apoptosis. In this study, we focused our attention on the apoptotic response of Alzheimer fibroblast-derived iPSCs and two other Alzheimer free iPSCs to five biologically relevant kinase inhibitors as well as to the death ligand TRAIL. To our knowledge, we are the first to report that the relatively high basal apoptotic rate of iPSCs is strongly suppressed by the pancaspase inhibitor QVD-Oph, thus underlining the dependency on proapoptotic caspase cascades. Furthermore, wortmannin, an inhibitor of phosphoinositid-3 kinase / Akt signaling (PI3K-AKT), dramatically and rapidly induced apoptosis in iPSCs. In contrast, parental fibroblasts as well as iPSC-derived neuronal cells were not responsive. The resulting condensation and fragmentation of DNA and decrease of the membrane potential are typical features of apoptosis. Comparable effects were observed with an AKT inhibitor (MK-2206). Wortmannin resulted in disappearance of phosphorylated AKT and activation of the main effector caspase-3 in iPSCs. These results clearly demonstrate for the first time that PI3K-AKT represents a highly essential survival signaling pathway in iPSCs. The findings provide improved understanding on the underlying mechanisms of apoptosis regulation in iPSCs.

Disseminated refractory pyoderma gangraenosum during an ulcerative colitis flare. Treatment with infliximab

BACKGROUND

Pyoderma gangraenosum is an immune-mediated, inflammatory, neutrophilic dermatosis of unknown etiology, which represents one of the extraintestinal manifestations of inflammatory bowel disease. It is a rare disease that occurs in less than 1% of patients with inflammatory bowel disease and with the same ratio in patients with Crohn's disease and ulcerative colitis.

MAIN OBSERVATIONS

A 36-year-old woman was diagnosed with ulcerative colitis 6 years before admission to our dermatology department with an acute disseminated pyoderma gangraenosum with mucosal involvement, during a flare of ulcerative colitis. Disease progression was interrupted by intravenous administration of the tumor necrosis factor-α inhibitor infliximab at 5 mg/kg at weeks 0, 2, and 6 (1st cycle) and every 8 weeks thereafter. Improvement of intestinal, skin and oral manifestations was evident already after the 1st cycle of treatment and has been maintained since (at least 16 months).

CONCLUSIONS

This case report is one of very few on disseminated pyoderma gangraenosum with oral involvement complicating ulcerative colitis, where infliximab was shown to have a rapid efficacy on skin, mucosal and bowel symptoms.

Skin mirrors human aging

Abstract Aged skin exhibits disturbed lipid barrier, angiogenesis, production of sweat, immune functions, and calcitriol synthesis as well as the tendency towards development of certain benign or malignant diseases. These complex biological processes comprise endogenous and exogenous factors. Ethnicity also markedly influences the phenotype of skin aging. The theories of cellular senescence, telomere shortening and decreased proliferative capacity, mitochondrial DNA single mutations, the inflammation theory, and the free radical theory try to explain the biological background of the global aging process, which is mirrored in the skin. The development of advanced glycation end-products and the declining hormonal levels are major factors influencing intrinsic aging. Chronic photodamage of the skin is the prime factor leading to extrinsic skin aging. The deterioration of important skin functions, due to intrinsic and extrinsic aging, leads to clinical manifestations, which mirror several internal age-associated diseases such as diabetes, arterial hypertension and malignancies.

Neuropeptides and skin aging

Abstract Neuropeptides (NP) are peptides that are released as chemical messengers from nerve cells. They act either in an endocrine manner, where they reach their target cells via the bloodstream or a paracrine manner, as co-transmitters modulating the function of neurotransmitters. To date approximately 100 different NP have been described in the literature. In recent years, several studies have documented that human skin expresses several functional receptors for NP, such as corticotropin-releasing hormone, melanocortins, β-endorphin, vasoactive intestinal polypeptide, neuropeptide Y and calcitonin gene-related peptide. These receptors modulate the production of inflammatory cytokines, proliferation, differentiation, lipogenesis and hormone metabolism in human skin cells. In addition, several NP are directly produced by human skin cells, indicating the complexity of understanding the real functions of NPs in human skin. In this review we address the possible effects of neuropeptides on the pathogenesis of aged skin.

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.

Malignant atrophic papulosis (Köhlmeier-Degos disease) - a review

Definition of the disease

Malignant atrophic papulosis (MAP), described independently by Köhlmeier and Degos et al., is a rare, chronic, thrombo-obliterative vasculopathy characterized by papular skin lesions with central porcelain-white atrophy and surrounding teleangiectatic rim.

Epidemiology

Less than 200 cases have been described in the literature. The first manifestation of MAP usually occurs between the 20th and 50th year of life.

Clinical description

The cutaneous clinical picture is almost pathognomonic. The histology is not consistent but in most cases it shows a wedge-shaped connective tissue necrosis in the deep corium due to a thrombotic occlusion of the small arteries. In the systemic variant, manifestations mostly occur at the intestine and central nervous system.

Etiology

The etiopathogenesis of the disease remains unknown, a genetic predisposition may occur. Vasculitis, coagulopathy or primary dysfunction of the endothelial cells have been implicated.

Diagnostic methods

Diagnosis is only based on the characteristic skin lesions.

Differrential diagnosis

It depends on the clinical presentation of MAP, but systemic lupus erythematosus and other connective tissue diseases need to be considered.

Management

No effective treatment exists for the systemic manifestations, while compounds that facilitate blood perfusion have achieved a partial regression of the skin lesions in single cases.

Prognosis

An apparently idiopathic, monosymptomatic, cutaneous, benign variant and a progressive, visceral one with approx. 50% lethality within 2–3 years have been reported. Systemic manifestations can develop years after the occurrence of skin lesions leading to bowel perforation and peritonitis, thrombosis of the cerebral arteries or massive intracerebral hemorrhage, meningitis, encephalitis, radiculopathy, myelitis.

New pharmaceutical concepts for sebaceous gland diseases: implementing today's pre-clinical data into tomorrow's daily clinical practice

The human sebaceous gland is a microscopic branched type multiacinar gland been present everywhere on the body except on the palms and soles, whereas they are sparsely located on the dorsum of hands and feet. Several medical conditions are related with sebaceous gland pathology, such as acne, sebaceous hyperplasia, sebaceous adenoma and sebaceous carcinoma. Acne is a common, complex, chronic disorder of the human pilosebaceous unit that mostly occurs in adolescence and young adulthood. The sebaceous gland plays an exquisite role in the initiation of the disease. The multifactorial nature of the pathogenesis of acne includes increased sebum production, alteration of the quality of sebum lipids, inflammatory processes, interaction with neuropeptides and dysregulation of the hormone microenvironment, follicular hyperkeratinization and inflammation maintained by Propionbacterium acnes products within the follicle. On the other hand, the sebaceous gland, as a major and critical compartment of human skin, is also affected through ageing, both intrinsic and extrinsic, which lead to distinct clinical and histological changes. Intrinsic ageing of the sebaceous gland is determined primarily by genetic factors and hormonal status, with androgens playing a major role. A clinical manifestation associated with intrinsic ageing changes is skin xerosis. Extrinsic ageing of human sebaceous gland is mainly caused by accumulating UV irradiation, especially UVA. Photoageing of sebaceous gland is expressed with a wide spectrum of benign and malignant sebaceous tumours, such as sebaceous hyperplasia, sebaceous carcinoma and Muir-Torre syndrome. This review will focus on the pathogenesis of the most common sebaceous gland diseases and their molecular pathways which may represent future pharmaceutical 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.

Skin anti-aging strategies

Skin aging is a complex biological process influenced by a combination of endogenous or intrinsic and exogenous or extrinsic factors. Because of the fact that skin health and beauty is considered one of the principal factors representing overall "well-being" and the perception of "health" in humans, several anti-aging strategies have been developed during the last years. It is the intention of this article to review the most important anti-aging strategies that dermatologists have nowadays in hand, including including preventive measurements, cosmetological strategies, topical and systemic therapeutic agents and invasive procedures.

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.

Alteration in N-glycomics during mouse aging: a role for FUT8

We recently reported that N-glycosylation changes during human aging. To further investigate the molecular basis determining these alterations, the aging process in mice was studied. N-glycan profiling of mouse serum glycoproteins in different age groups of healthy C57BL/6 mice showed substantial age-related changes in three major N-glycan structures: under-galactosylated biantennary (NGA2F), biantennary (NA2), and core α-1,6-fucosylated -β-galactosylated biantennary structures (NA2F). Mice defective in klotho gene expression (kl/kl), which have a shortened lifespan, displayed a similar but accelerated trend. Interestingly, the opposite trend was observed in slow-aging Snell Dwarf mice (dw/dw) and in mice fed a calorically restricted diet. We also discovered that increased expression and activity of α-1,6-fucosyltransferase (FUT8) in the liver are strongly linked to the age-related changes in glycosylation and that this increased FUT8 and fucosylation influence IGF-1 signaling. These data demonstrate that the glycosylation machinery in liver cells is significantly affected during aging and that age-related increased FUT8 activity could influence the aging process by altering the sensitivity of the IGF-1R signaling pathway.

An update on the role of the sebaceous gland in the pathogenesis of acne

The pathogenesis of acne, a disease of the pilosebaceous follicle and one of the most common chronic skin disorders, is attributed to multiple factors such as increased sebum production, alteration of the quality of sebum lipids, inflammatory processes, dysregulation of the hormone microenvironment, interaction with neuropeptides, follicular hyperkeratinisation and the proliferation of Propionibacterium acnes within the follicle. In particular, the sebaceous gland plays an exquisite role in the initiation of the disease as it possesses all the enzyme machinery for the production of hormones and cytokines. In addition, in response to the altered tissue environment in the pilosebaceous follicle as well as in answer to emotional fret, stress response system mechanisms with induction of central and local expression of neuropeptides, are also initiated. This review summarises the latest advances in understanding the role of sebaceous gland cells in the pathomechanism of acne.

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.

Treating acne with antibiotic-resistant bacterial colonization

INTRODUCTION

Acne is a chronic skin disorder of the pilosebaceous unit; it has a multifactorial pathogenesis. Propionibacterium acnes within the follicle is considered to be a triggering factor of inflammation in acne. Antibiotics have been the primary treatment against P. acnes for more than 40 years. However, a gradual increase in the prevalence of antibiotic-resistant strains of P. acnes has been observed.

AREAS COVERED

This review discusses the pathophysiology of antibiotic-resistant acne development. It focuses on strategies to minimize the development of resistance and, most importantly, confront the development of antibiotic-resistant acne. The literature search was conducted up to August 2010, using the search terms 'acne', 'antibiotic-resistant acne' and 'bacterial resistance'.

EXPERT OPINION

Antibiotic-resistant acne is a real phenomenon. Strategies to prevent and confront it should include not only the use of certain treatment regimens but also rational prescribing policies, combination therapies, use of antibacterial non-antibiotic agents and treatment options targeting all the pathogenetic components of acne. Benzoyl-peroxide-based treatment is the most evidence-based approach. Oral isotretinoin remains the most efficacious option for severe acne.

[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.

Elevated sex steroid hormones in great saphenous veins in men

INTRODUCTION

High serum levels of estradiol are associated with clinical evidence of varicose veins in women; however, the relationship between serum sex steroid hormones and varicose veins in men is unclear. To address this issue, serum levels of testosterone, estradiol, and androstenedione were determined in the great saphenous (GSV) and cubital veins of men with varicose veins. Messenger RNA (mRNA) expression of sex steroid hormones, metabolizing enzymes, and their receptors was investigated in tissue samples of leg veins.

METHODS

This prospective study included 40 men, comprising 20 with varicose veins and reflux of the GSV (VM) and 20 with healthy veins (HM). All limbs were assessed by duplex ultrasound scanning of selected superficial and deep leg veins. Blood samples were taken from the cubital vein and from the GSV. Quantitative reverse-transcription polymerase chain reaction (qRT-PCR) analysis for sex steroid hormones, their metabolizing enzymes, and receptors in saphenous veins was performed in tissue samples of varicose (n = 6) and healthy veins (n = 6).

RESULTS

The VM group had significantly higher (P < .001) mean levels for serum testosterone (44.9 nmol/L; range, 8.8-225.1) and estradiol (242.2 pmol/L; range, 79-941) in varicose saphenous veins compared with cubital veins (testosterone, 15.5 nmol/L; range, 8.4-23.3; estradiol, 93.2 pmol/L; range, 31-147). Moreover, significantly (P < .001) higher mean serum estradiol levels (133.2 pmol/L; range, 63-239) were detected in the saphenous veins of the HM group compared with cubital veins (88.15 pmol/L; range, 37-153). Both groups had similar blood counts and serum androstenedione levels in the upper and lower extremity. Interestingly, qRT-PCR revealed that the mRNA expression of 5alpha-reductase type 1, 5alpha-reductase type 2, 17, 20 lyase, 17beta-hydroxysteroid dehydrogenase (17beta-HSD), aromatase and 3beta-HSD type 2, androgen and estrogen receptor 1 was down-regulated (P < .05) in all samples of varicose veins vs veins obtained from healthy men.

CONCLUSION

Elevated serum estradiol and testosterone levels were detected in men with varicose veins and reflux in the GSV compared with the patient's own arm veins. Enzymes and hormonal receptors involved in steroid metabolism were down-regulated in patients with GSV reflux and varicose veins, suggestive of a negative feedback regulation. These data support the notion of a possible causal relationship between sex steroids and varicose veins in men.

Androgens and ageing of the skin

PURPOSE OF REVIEW

This study reviews current advances in our understanding of the role of androgens in the initiation of skin ageing.

RECENT FINDINGS

Skin and its appendages being a steroidogenic tissue itself can be affected to a large extent by sex steroids. Amongst them, androgens display a distinguished role. They modulate epidermal and dermal thickness as proven in a variety of studies measuring gender-specific differences. With advanced age, changes in the circulating androgen levels may alter not only the morphology but also key functions of the skin such as epidermal barrier homeostasis and wound healing, sebaceous gland growth and differentiation and hair growth.

SUMMARY

Consequently, skin becomes susceptible to infections and several disease states. Androgen treatment has been proposed to be an effective way to reverse the age-associated deterioration of skin; however, further research is needed to translate current findings to clinically significant diagnostic and therapeutic applications.