The ageing dermis: the main cause for the appearance of 'old' skin

Thioredoxin promotes the regeneration and binding of elastic fibre and basement membrane

OBJECTIVE

Thioredoxin (TRX), a ubiquitous protein with strong antioxidant activity, decreases in the skin with age. A decrease in TRX is expected to induce cellular senescence, chronic inflammation, and degeneration and loss of extracellular matrix (ECM), such as collagen and elastin within the skin. In this study, we investigated the effects of TRX addition to excised skin or skin models to understand the role of TRX on cells and ECM within the skin.

METHODS

To evaluate its effect on skin cells, we cultured a three-dimensional (3D) skin model in a medium containing TRX. The mRNA expression levels of proteins related to elastic and collagen fibres and the basement membrane were determined. Furthermore, 3D imaging and computational analysis were performed to evaluate the effect of TRX on the elastic fibres and extending COL VII structures in excised human skin after coculturing with TRX for 1, 4, 5 and 6 days.

RESULTS

Thioredoxin application to a 3D skin model upregulated elastin, COLI and COLVII mRNA expression. Applying TRX to the excised skin increased the number of linear elastic fibres. This effect of TRX demonstrated a daily increment in a dose-dependent manner. Thioredoxin extended the fibrous structure of COL VII into the dermis, expanding its colocalization region with elastic fibres. These structural effects were confirmed using 3D imaging and computational methods.

CONCLUSION

Thioredoxin elongates elastic fibres from the dermis to the basement membrane and extends the COL VII structure from the basement membrane to the dermis in excised human skin. These findings suggest the potential of TRX to protect the skin against age-related alterations such as wrinkles and sagging.

Carbon dioxide-induced decrease in extracellular pH enhances the production of extracellular matrix components by upregulating TGF-β1 expression via CREB activation in human dermal fibroblasts

Mild acidification caused by transcutaneous administration of carbon dioxide (CO2 ) has been reported to improve some epidermal skin impairments, such as desquamation and inflammation; however, its effects on dermal tissue remain unclear. Here, we examined the effect and mechanism of mild acidity on extracellular matrix (ECM) protein production in normal human dermal fibroblasts (NHDFs). To achieve this, the skin permeability of CO2 and its effect on intradermal pH were evaluated by treating reconstructed human skin equivalents (HSEs) with a CO2 -containing formulation. Additionally, NHDFs were cultured in a pH-adjusted medium (pH 6.5). CO2 successfully permeated HSEs and reduced the intradermal pH. Decreased extracellular pH activated CREB, upregulated TGF-β1 expression, promoted the production of elastic and collagen fibres, and increased hyaluronan concentration in NHDFs. Additionally, the low pH-induced increase in TGF-β1 expression was attenuated via the RNAi-mediated suppression of the expression of CREB1 and proton-sensing G protein-coupled receptors (GPCRs), including GPR4 and GPR65. Moreover, low pH-induced CREB activation was suppressed by the inhibition of the cAMP/PKA and PLC/PKC signalling pathways. Taken together, a CO2 -induced decrease in intradermal pH may promote ECM production in NHDFs via the upregulation of TGF-β1 expression, which was mediated by the activation of the GPCR signalling pathway and CREB, indicating that CO2 could be used to treat ultraviolet radiation-induced photoaging, intrinsic ageing and ECM deterioration.

A novel optical coherence tomography-based in vitro method of anti-aging skin analysis using 3D skin wrinkle mimics

BACKGROUND

Wrinkles represent a characteristic symptom of skin aging. In recent years, various studies have focused on their prevention and/or cure. However, clinical tests are still the only method available to directly detect and evaluate the anti-wrinkle efficacy of various substances. Moreover, no in vitro strategy for such anti-aging skin analysis has been reported. Therefore, in this study, we aimed to develop a novel technology to overcome these limitations.

MATERIALS AND METHODS

Full-thickness (FT) skin wrinkle mimics with various widths and depths were fabricated using a collagen stamping method. These were analyzed and compared using 2D and 3D Swept Source-Optical Coherence Tomography (SS-OCT) imaging technologies.

RESULTS

SS-OCT demonstrated superficial and cross-sectional images of the wrinkle mimics, and the size of the wrinkles was validated using image analysis. Retinoic acid treatment significantly decreased both the depth and width of wrinkles formed in the FT skin wrinkle mimics.

CONCLUSIONS

Using 3D tissue engineering and SS-OCT imaging technologies, we developed a novel in vitro technique that can directly detect skin wrinkles. This significantly efficient method could lead to an alternative strategy for animal experiments and preclinical anti-aging research on the skin.

The Effect of Ascorbic Acid Supplementation on the Time of Healing of Rats Submitted to Neurosurgical Procedures

Introduction Vitamin C is an essential nutrient for both humans and rats and has been noted for its beneficial properties, among them, healing.

Objective To verify the effect of oral and subcutaneous vitamin C supplementation on the healing time of surgical wounds of rats skulls.

Statistical Methodology Thirty male Wistar rats were divided into 3 groups: 10 from the control group (GI), 10 from the group treated with oral vitamin C (GII), and 10 from the group treated with subcutaneous vitamin C (GIII). Vitamin C was administered to GI and GIII animals from the 3rd to the 7th postoperative day, totaling 10 days of administration at a dose of 100 mg/kg/day. On the 4th day of the study, the rats were submitted to a surgical procedure consisting of a 2-cm incision of the skin of the animals' heads and suturing with single stitches. After a determined period, the rats were killed and submitted to the collection of material for study by the picrosirius red technique for the evaluation of collagen types I and III, the degree of hematoxylin and eosin healing, and the rate of contraction of the wound on subsequent days. The results were described in averages, medians, minimum and maximum values, and standard deviations. For the comparison of the three groups, the analysis of variance with one factor (one-way ANOVA) or Kruskal-Wallis non-parametric test was used. The normality of the variables was evaluated by the Shapiro-Wilk test. Values of p < 0.05 indicated statistical significance. The data were analyzed using the IBM SPSS Statistics for Windows, v.20.0. software. (IBM Corp., Armonk, NY, USA).

Results The amount of collagen type III was higher in the groups that received vitamin C, however, without significant difference (n = 0.292). In relation to the rate of contraction of the surgical wound, it was higher in the groups treated with vitamin C, with a significant difference between groups I and II (p = 0.001), and between groups I and III (p < 0.001). No significant difference was found between the groups that were treated with vitamin C (p = 0.227).

Conclusion Healing was more effective in the groups treated with vitamin C than in the group that did not receive vitamin supplementation. There was no significant difference in healing between the groups receiving oral or subcutaneous vitamin C.

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

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

Application of high-frequency ultrasound to assess facial skin thickness in association with gender, age, and BMI in healthy adults

Background and objective

High-frequency ultrasound plays an extremely important role in normal skin measurement, skin disease diagnosis, and aesthetic medicine. This study aimed to estimate the epidermal and dermal thicknesses at eight different facial sites in healthy adults using high-frequency ultrasound, and to evaluate the correlation of epidermal and dermal thicknesses with age and body mass index (BMI).

Methods

Facial skin assessment was performed on 118 participants using high-frequency ultrasound. The epidermal and dermal thicknesses of forehead, glabella, temple, eyelid, nasal dorsum, zygoma, submandibular, and neck were measured. The correlation of the epidermal and dermal thicknesses with age and BMI was analyzed by the linear correlation analysis.

Results

The epidermal and dermal thicknesses in men were significantly higher than those in women (P < 0.05), except for the thicknesses of zygomatic epidermis and neck dermis. The dermal thickness on zygoma and submandibular in young women was significantly higher than in middle age and old women (P < 0.05). Overall, with the increase of age, the thickness of facial skin decreased in women, mainly in the forehead, glabella, zygoma, and submandibular. In women, the epidermal and dermal thicknesses of neck were correlated with BMI (r = 0.392, 0.241, P < 0.05, respectively). However, in men, the epidermal and dermal thicknesses were correlated with age only in zygoma dermis (r = − 0.327, P < 0.05), while there was no correlation between the epidermal and dermal thicknesses and BMI.

Conclusion

Gender, age, and BMI had significant effects on the epidermal and dermal thicknesses at different facial sites.

Effectiveness of a Radiofrequency Device for Rejuvenation of Aged Skin at Home: A Randomized Split-Face Clinical Trial

Introduction

Methods

Results

Conclusions

In Vitro and Clinical Evaluation of Cannabigerol (CBG) Produced via Yeast Biosynthesis: A Cannabinoid with a Broad Range of Anti-Inflammatory and Skin Health-Boosting Properties

Cannabigerol (CBG) is a minor non-psychoactive cannabinoid present in Cannabis sativa L. (C. sativa) at low levels (<1% per dry weight) that serves as the direct precursor to both cannabidiol (CBD) and tetrahydrocannabinol (THC). Consequently, efforts to extract and purify CBG from C. sativa is both challenging and expensive. However, utilizing a novel yeast fermentation technology platform, minor cannabinoids such as CBG can be produced in a more sustainable, cost-effective, and timely process as compared to plant-based production. While CBD has been studied extensively, demonstrating several beneficial skin properties, there are a paucity of studies characterizing the activity of CBG in human skin. Therefore, our aim was to characterize and compare the in vitro activity profile of non-psychoactive CBG and CBD in skin and be the first group to test CBG clinically on human skin. Gene microarray analysis conducted using 3D human skin equivalents demonstrates that CBG regulates more genes than CBD, including several key skin targets. Human dermal fibroblasts (HDFs) and normal human epidermal keratinocytes (NHEKs) were exposed in culture to pro-inflammatory inducers to trigger cytokine production and oxidative stress. Results demonstrate that CBG and CBD reduce reactive oxygen species levels in HDFs better than vitamin C. Moreover, CBG inhibits pro-inflammatory cytokine (Interleukin-1β, -6, -8, tumor necrosis factor α) release from several inflammatory inducers, such as ultraviolet A (UVA), ultraviolet B (UVB), chemical, C. acnes, and in several instances does so more potently than CBD. A 20-subject vehicle-controlled clinical study was performed with 0.1% CBG serum and placebo applied topically for 2 weeks after sodium lauryl sulfate (SLS)-induced irritation. CBG serum showed statistically significant improvement above placebo for transepidermal water loss (TEWL) and reduction in the appearance of redness. Altogether, CBG’s broad range of in vitro and clinical skin health-promoting activities demonstrates its strong potential as a safe, effective ingredient for topical use and suggests there are areas where it may be more effective than CBD.

AGSE: A Novel Grape Seed Extract Enriched for PP2A Activating Flavonoids That Combats Oxidative Stress and Promotes Skin Health

Environmental stimuli attack the skin daily resulting in the generation of reactive oxygen species (ROS) and inflammation. One pathway that regulates oxidative stress in skin involves Protein Phosphatase 2A (PP2A), a phosphatase which has been previously linked to Alzheimer’s Disease and aging. Oxidative stress decreases PP2A methylation in normal human dermal fibroblasts (NHDFs). Thus, we hypothesize agents that increase PP2A methylation and activity will promote skin health and combat aging. To discover novel inhibitors of PP2A demethylation activity, we screened a library of 32 natural botanical extracts. We discovered Grape Seed Extract (GSE), which has previously been reported to have several benefits for skin, to be the most potent PP2A demethylating extract. Via several fractionation and extraction steps we developed a novel grape seed extract called Activated Grape Seed Extract (AGSE), which is enriched for PP2A activating flavonoids that increase potency in preventing PP2A demethylation when compared to commercial GSE. We then determined that 1% AGSE and 1% commercial GSE exhibit distinct gene expression profiles when topically applied to a 3D human skin model. To begin to characterize AGSE’s activity, we investigated its antioxidant potential and demonstrate it reduces ROS levels in NHDFs and cell-free assays equal to or better than Vitamin C and E. Moreover, AGSE shows anti-inflammatory properties, dose-dependently inhibiting UVA, UVB and chemical-induced inflammation. These results demonstrate AGSE is a novel, multi-functional extract that modulates methylation levels of PP2A and supports the hypothesis of PP2A as a master regulator for oxidative stress signaling and aging in skin.

Fractional 1064 nm picosecond laser and skin photoaging: in vivo evaluation of treatment effects with reflectance confocal microscopy

Few studies showed the role of picosecond laser (PLS) in the treatment of skin photoaging signs. However, no studies have explored the microscopic effects of PSL in photoaging. The aim of this study is to preliminarily identify clinical variations induced by a 1,064 nm Nd:YAG PSL on the décolleté area, then to apply the treatment protocol to treat facial photoaging and estimate the clinical and microscopic outcomes. A total of 10 consecutive patients with cutaneous photoaging were enrolled. Patients were treated 3 times at monthly intervals with the fractionated 1,064 nm Nd:YAG PSL. In a preliminary phase, PSL treatment was performed on the décolleté to establish its efficacy and safety. Then, the same treatment protocol was applied to all the face and clinical and reflectance confocal microscopy (RCM) were analyzed, comparing baseline (T0) pictures and 4 months after the treatment (T1) ones. On the face, a reduction of dyschromia and wrinkles was observed at T1. Furthermore, the underlying RCM variations were revealed at different skin levels. Our results show the clinical and microscopic effectiveness and safety of the 1,064-nm Nd:YAG PSL in the treatment of skin photoaging signs.

A new treatment for static forehead rhytides: Autologous fibroblast and keratin injection

OBJECTIVE

To assess the effectiveness of injection of autologous keratin gel and fibroblast for static forehead rhytides rectification as new soft tissue filler.

MATERIALS AND METHODS

Totally, 48 volunteers suffering static forehead rhytides received the injection of autologous keratin and fibroblast, and 6 volunteers received botulinum toxin type A (BTX-A) and hyaluronic acid (HA) treatment as parallel control. The follow-up study was carried out at 1, 3, 6, 12, and 24 months after treatment, and photographs and satisfactions questionnaire were collected and assessed. All volunteers were independently assessed by blinded evaluators using global aesthetic improvement scores (GAIS). One-way Anova was used for statistical analysis, and the significant level was α=0.05).

RESULTS

The static forehead rhytides were improved observably after the treatment. It still showed good result even at month 24 after the injection. There are no severe adverse effects observed in the whole procedure.

CONCLUSION

Autologous fibroblast and keratin combined injection might be an ideal therapy in mini-invasive plastic injection area, which is safe and effective for static forehead rhytides correction, and has a long-term efficacy.

Chitosan hydrogel-loaded MSC-derived extracellular vesicles promote skin rejuvenation by ameliorating the senescence of dermal fibroblasts

Background

The senescence of dermal fibroblasts (DFLs) leads to an imbalance in the synthesis and degradation of extracellular matrix (ECM) proteins, presenting so-called senescence-associated secretory phenotype (SASP), which ultimately leads to skin aging. Recently, mesenchymal stem cell (MSC)-derived extracellular vesicles (EVs) have been recognized as a promising cell-free therapy for degenerative diseases, which opens a new avenue for skin aging treatment.

Methods

In this study, we utilized chitosan (CS) hydrogel for effective loading and sustained release of EVs. In vitro, we explored the rejuvenation effects of CS hydrogel-incorporated EVs (CS-EVs) on replicative senescence DFLs through a series of experiments such as senescence-associated β-galactosidase (SA-β-gal) staining, RT-PCR, and Western blot analysis. Besides, we employed local multi-site subcutaneous injection to treat skin aging of naturally aged mice with CS-EVs and DiI fluorescent dye was used to label EVs to achieve in vivo real-time tracking.

Results

CS-EVs can significantly improve the biological functions of senescent fibroblasts, including promoting their proliferation, enhancing the synthesis of ECM proteins, and inhibiting the overexpression of matrix metalloproteinases (MMPs). Moreover, CS hydrogel could prolong the release of EVs and significantly increase the retention of EVs in vivo. After CS-EVs subcutaneous injection treatment, the aging skin tissues showed a rejuvenation state, manifested explicitly as the enhanced expression of collagen, the decreased expression of SASP-related factors, and the restoration of tissue structures.

Conclusions

CS hydrogel-encapsulated EVs could delay the skin aging processes by ameliorating the function of aging DFLs. Our results also highlight the potential of CS hydrogel-encapsulated EVs as a novel therapeutic strategy for improving aging skin to rejuvenation.

The efficacy and safety of an antiaging topical serum containing hesperetin and sodium cyclic lysophosphatidic acid: A single-center clinical trial

BACKGROUND

Skin aging is characterized by dehydration and degradation of the structural components in the dermis. It has been demonstrated that hesperetin possesses collagen synthesis and antioxidant properties and sodium cyclic lysophosphatidic acid (NcPA) increases skin moisture through upregulating the synthesis of hyaluronic acid.

AIMS

To evaluate the efficacy and safety of a serum containing hesperetin 0.1% and NcPA 0.1% for photoaged skin.

PATIENTS/METHODS

The trial consisted of a 12-week topical application of the test product twice daily. A total of 35 female subjects were enrolled. The primary outcome was the change of skin hydration and elasticity, which were determined by Corneometer and Cutometer measurements. Skin biopsy for histological evaluations and subject's self-assessment were conducted.

RESULTS

At week 12, a significant improvement of stratum corneum hydration (p = 0.015) and skin elasticity (p < 0.001) was detected comparing to baseline. The skin biopsy showed significantly improved scores of hyaluronic acid levels (p = 0.034) and elastic fiber structure (p = 0.023). Moreover, the test product resulted in a significant subject-reported overall satisfaction rate 94.3% after 12-week application (p = 0.005).

CONCLUSION

Skin care product containing hesperetin and NcPA showed significant antiaging effects on skin hydration and elasticity.

Comparison of microfocused ultrasound with visualization for skin laxity among vegan and omnivore patients

BACKGROUND

The aging of facial structures depends on genetic, anatomic, chronologic, and environmental factors that affect the skin and underlying tissues. Microfocused ultrasound with visualization (MFU-V) has emerged as a safe and effective treatment for skin laxity. As the nutritional status may contribute to skin aging, it would be interesting to evaluate whether different dietary patterns can also influence the response to MFU-V treatment for skin laxity.

AIMS

The aim of this study is to compare the outcome of MFU-V therapy between omnivore and vegan patients.

METHODS

Twenty-seven vegan and twenty-seven omnivorous women who underwent MFU-V treatment for laxity of lower face and neck were enrolled. The clinical outcome was evaluated using the FLR (Facial Laxity Rating) scale after 3 and 6 months from treatment.

RESULTS

At baseline, no significant differences were found in terms of FLR scale in both treated sites. After 3 months, reduction in FLR scale was significantly lower for vegans both on face (P = .04) and neck (P = .004). At 6 months, vegan patients had a worse clinical outcome on lower face (P = .001) and neck (P < .001).

CONCLUSION

The present study suggests that a vegan diet may negatively influence the outcome of a MFU-V treatment.

Potential anti-ageing effect of chondroitin sulphate through skin regeneration

OBJECTIVE

Skin ageing is inevitably exposed through its typical features such as wrinkles and sagging. Therefore, skin anti-ageing is a major issue in cosmetic research to prevent and improve ageing symptoms using effective ingredients. Chondroitin sulphate (CS), a type of glycosaminoglycan, is an important structural component of the extracellular matrix (ECM) and is involved in various biological processes, such as cell proliferation, differentiation and migration. Here, we aimed to investigate the effects of CS on skin regeneration and examine its efficacy as a potential safe and effective skin anti-ageing ingredient.

METHODS

We investigated the effects of CS on cell proliferation in normal human keratinocytes and fibroblasts. Then, cell migration, ECM synthesis and related signalling pathways were examined in fibroblasts through gene and protein expression analysis. Finally, the effect on skin wound healing and regeneration was validated using a full-thickness skin wound model and an aged skin model.

RESULTS

Chondroitin sulphate treatment increased the proliferation of keratinocytes and fibroblasts. It also stimulated the migration and synthesis of ECM components of fibroblasts. Further analysis revealed that CS induced the expression of type I procollagen by activating the extracellular signal-regulated kinase pathway. Using a full-thickness skin wound model and an aged skin model, we confirmed that CS treatment promoted skin wound healing and regeneration.

CONCLUSION

Together, our results indicated that CS has the potential to facilitate skin regeneration, implying that CS could be clinically applied to improve skin ageing.

Improvements in Skin Quality Biological Markers in Skin Explants Using Hyaluronic Acid Filler VYC-12L

Hyaluronic acid (HA), both crosslinked and uncrosslinked, is used clinically to treat fine lines and provides additional improvements in skin quality attributes. The purpose of this study was to assess potential early differences in the expression of biological markers of skin quality in living human skin explants injected with uncrosslinked and crosslinked HA gels.

Methods

Living human skin explants injected with VYC-12L or noncrosslinked HA with mannitol (HYD) and noninjected controls were assessed via microscopy, histology, and immunohistochemistry on days 3 and/or 8 for biological markers of elasticity (collagen density, elastin, fibrillin-1) and hydration [aquaporin-3, acidic glycosaminoglycans (GAGs), HA]. Hydration was also assessed via a corneometer probe on days 0, 1, 2, and 8.

Results

On day 3 versus controls, VYC-12L moderately increased collagen density in the upper reticular dermis and clearly increased fibrillin-1 expression, with slight increases persisting on day 8. Increases with HYD were smaller and did not persist on day 8. Both VYC-12L and HYD increased aquaporin-3 expression and GAG content on days 3 and 8, but VYC-12L produced greater GAG increases in the reticular dermis. Day 8 instrument-assessed hydration increased by 49% and 22% for VYC-12L and HYD, respectively. Elastin expression in oxytalan and elaunin fibers was unchanged. Upper-dermal HA reductions suggested HA injection-induced hyaluronidase expression.

Conclusion

VYC-12L produced greater, more lasting improvements in biological markers of skin quality than HYD.

VYC-12 Injectable Gel Is Safe And Effective For Improvement Of Facial Skin Topography: A Prospective Study

Objective

Evaluate safety and effectiveness of VYC-12 (Juvéderm Volite; an injectable crosslinked hyaluronic acid gel designed to improve skin quality attributes such as surface smoothness and hydration) for facial intradermal injection.

Materials and methods

In a prospective, single-arm study, subjects with moderate/severe cheek skin roughness per Allergan Skin Roughness Scale (ASRS) received VYC-12 in the cheeks and forehead, and/or neck, with touch-up treatment to correct asymmetry 30 days later and optional repeat treatment 9 months after last treatment. The primary effectiveness measure was ASRS responder rate (percentage of cheeks with ≥1-point improvement from baseline) at month 1. Skin hydration was instrument-assessed.

Results

Of 131 subjects treated, 31 (23.7%) received touch-up treatment. ASRS responder rate was 96.2% at month 1, 76.3% at month 4, 34.9% at month 6, and 87.1% after repeat treatment. Responder rate in cheeks with severe baseline roughness was 93.8%, 83.1%, and 52.3% at months 1, 4, and 6, respectively. Skin hydration improved significantly (P<0.01) from baseline at all timepoints through month 9. Injection site responses were as expected. All treatment-related adverse events were mild/moderate.

Conclusion

VYC-12 safely and effectively improved skin smoothness up to 6 months and hydration lasting 9 months.

A novel multifunctional skin care formulation with a unique blend of antipollution, brightening and antiaging active complexes

BACKGROUND

High demand on anti-aging skin care encourage the improvement and development of more personalized formulations with additional benefits for general skin health and age associated skin signs. The skin aging physical and biological phenotypes manifest differently between diverse ethnic populations. A highly polluted environment can be viewed as an extrinsic factor accelerating the skin aging process.

AIM

To develop a unique formula with active complexes, having multifunctional effects for anti-pollution, brightening and anti-aging/barrier strengthening purposes with confirmed activities in vitro and ex vivo skin models, suitable for polluted skin.

METHODS

In vitro culture model with primary human skin cells, ex vivo studies with full-thickness human skin, melanocyte 3D coculture model, gene expression of epidermal and dermal genes, anti-glycation, proteasomal activity, melanin, and cytokine assays.

RESULTS

In vitro and ex vivo studies clearly demonstrated that diglucosyl gallic acid (active A) and the formulation complex inhibited pollution mediated MMP1 protein, CYP1A1 gene expression, and IL-6 protein secretion, while caprylic/capric triglyceride, diacetyl boldine (active B) had anti-melanogenic effect in in vitro primary melanocyte monoculture and 3D spheroid model. Another active compound, acetyl dipeptide 1 cetyl ester (active D), significantly upregulated epidermal barrier genes (Aquaporin 3 [AQP3], Filaggrin [FLG], caspase 14, and keratin 10) in human primary keratinocytes. Interestingly, both acetyl dipeptide 1 cetyl ester (active D) and niacinamide (active C) improved dermal gene expression (fibrillin-1, Collagen type 1 alpha 1, Decorin, Lysyl oxidase-like 1) and, moreover, had significant anti-glycant and proteasomal promoter activity in human primary fibroblasts.

CONCLUSION

Considering consumers need in heavily polluted areas, we developed a multipurpose formulation comprised of unique active complexes toward pollution, pollution induced inflammation, skin brightening, and antiaging concerns with beneficial results demonstrated by in vitro and ex vivo studies.

Molecular Mechanisms of Dermal Aging and Antiaging Approaches

The dermis is primarily composed of the extracellular matrix (ECM) and fibroblasts. During the aging process, the dermis undergoes significant changes. Collagen, which is a major component of ECM, becomes fragmented and coarsely distributed, and its total amount decreases. This is mainly due to increased activity of matrix metalloproteinases, and impaired transforming growth factor-β signaling induced by reactive oxygen species generated during aging. The reduction in the amount of collagen hinders the mechanical interaction between fibroblasts and the ECM, and consequently leads to the deterioration of fibroblast function and further decrease in the amount of dermal collagen. Other ECM components, including elastic fibers, glycosaminglycans (GAGs), and proteoglycans (PGs), also change during aging, ultimately leading to a reduction in the amount of functional components. Elastic fibers decrease in intrinsically aged skin, but accumulate abnormally in photoaged skin. The changes in the levels of GAGs and PGs are highly diverse, and previous studies have reported conflicting results. A reduction in the levels of functional dermal components results in the emergence of clinical aging features, such as wrinkles and reduced elasticity. Various antiaging approaches, including topicals, energy-based procedures, and dermal fillers, can restore the molecular features of dermal aging with clinical efficacy. This review summarizes the current understanding of skin aging at the molecular level, and associated treatments, to put some of the new antiaging technology that has emerged in this rapidly expanding field into molecular context.

Clinical purpura and elastosis and their correlation with skin tears in an aged population

The previous research reported the results of a prospect cohort study that used logistic regression analysis to construct a risk prediction model for skin tears in individuals aged over 65 years. The model identified three baseline individual characteristics (male gender, history of STs, and history of falls) and two baseline skin manifestations (purpura and elastosis) that predicted the risk of dorsal forearm skin tears. This paper outlines the relationships between baseline skin manifestations and the risk of skin tears. Univariable logistic regression analysis was conducted of all the baseline data collected from the same-study participants to identify variables that significantly predicted purpura and elastosis at baseline. Amongst the 173 participants, 71 (41%) developed one or more skin tears, and in these participants, 52 (73.2%) displayed purpura, 41 (57.8%) had elastosis, and 30 (42.3%) exhibited both manifestations of the dorsal forearm at baseline. Four individual characteristics (age, history of skin tears, history of falls, and antiplatelet therapy) and three skin properties (pH, subepidermal low echogenicity band of the forearms, and skin thickness) were found to predict the risk of purpura. Conversely, three individual variables (age, gender, and smoking), three clinical skin variables (uneven skin pigmentation, cutis rhomboidalis nuchae, and history of actinic keratosis) and one skin property variable (collagen type IV) predicted the risk of skin elastosis. Progressive changes to the skin's structural and mechanical properties from the underlying effects of chronological ageing, and environmental and lifestyle-related influences increased the risk of purpura and elastotic skin manifestations and concomitantly increased risk of skin tears amongst participants.

Influences of age, ethnic group, and skin sites on a provisory skin marking, experimentally induced, in vivo

BACKGROUND

To study capacity of skin to being imprinted by a marking head rapidly applied (10 seconds) onto the skin under a standardized pressure (15 kPa).

MATERIAL AND METHODS

Referential photographs of skin markings, resulting from different times of application serve at grading the extent of skin imprints. The imprinting tool, equipped with 5 linear bulbs of different sizes but same thickness (1 mm), was applied onto the cheeks of 641 women of different ages (18-80 years) of 3 different ethnic groups. In the cohort of 198 Caucasian women, the marking head was pressed onto 3 different sites (outer arm, cheek, and dorsal forearm) and the kinetics of skin recovery from cheek marking was recorded on a smaller and younger part of this Caucasian cohort, ie, 141 Caucasian women, aged 18-59 years.

RESULTS

The recorded intensities of skin markings were found highly correlated with age in all 3 studied ethnic groups (Chinese, African-American, and Caucasian). Caucasian women seem more sensitive to the marking and the kinetics of recovery from such imprint was found highly dependent from its intensity, ie, the higher the grades, the slower the recovery. In Caucasian women, intensities were different between skin sites, where arm showed higher resistance to marking. Possible impact of photo-aging on the decreased skin resistance to such provoked deformation is likely of minor amplitude, as compared to the one induced by chronological aging.

CONCLUSION

This method offers a new vision on skin aging, in its variable response to a standard deformation that appears mostly driven by chronological aging.

Dynamic smile evaluation in different skeletal patterns

Objective:

To evaluate dynamic smile in different skeletal patterns and to correlate vertical smile parameters with the underlying causative factors.

Materials and Methods:

A total of 150 participants ranging in age from 16–25 years were selected and divided into one of three groups—horizontal, average, and vertical skeletal pattern—using the following three cephalometric parameters: SN-MP, FMA, and Jarabak ratio. Videographic records of smile were obtained, and measurements were recorded and analyzed at rest, including upper lip length, and during smile, including maxillary incisal display, interlabial gap, intercommisural width, change in upper lip length, and smile arc. Differences among the three groups were subjected to two-way analysis of variance and post hoc and chi-square tests for smile arc. Correlations between vertical smile variables and vertical skeletal (N-ANS, N-Me) and dental cephalometric measurements (U1 to palatal plane) were also investigated.

Results:

Vertical parameters were significantly increased in the vertical pattern when compared with the horizontal pattern, ie, upper lip length (P &lt; .01), maxillary incisal display (P &lt; .001), interlabial gap (P &lt; .001), and change in upper lip length (P &lt; .001), whereas intercommisural width was significantly decreased in vertical pattern when compared with the horizontal pattern (P &lt; .001). Flat smile arc was seen more frequently in the horizontal pattern. Positive correlations were found between the N-Me, U1-PP, and change in upper lip length with vertical smile parameters.

Conclusions:

Different skeletal patterns exhibit their characteristic smile features. Upper lip length is not responsible for increased incisal display during smile. Increased incisal display during smile is more closely associated with upper lip elevation than vertical skeletal and dental factors.

In vitro and clinical evaluation of SIG1273: a cosmetic functional ingredient with a broad spectrum of anti-aging and antioxidant activities

BACKGROUND

Isoprenylcysteine (IPC) small molecules were identified as a new class of anti-inflammatory compounds over 20 years ago. Since then, they have been developed as novel cosmetic functional ingredients (CFI) and topical drug candidates. SIG1273 is a second generation CFI that has previously been shown to provide a broad spectrum of benefits for the skin through its anti-inflammatory and antimicrobial properties.

OBJECTIVE

To determine whether SIG1273 possesses anti-aging properties in vitro and evaluate the tolerability and activity of SIG1273 when applied topically to human subjects.

METHODS

To model photoaging in vitro, human dermal fibroblasts (HDFs) were exposed in culture to UVA to induce collagenase (MMP-1) production. An in vitro wound-healing model was based on the activation of HDF migration into cell-free tissue culture surface. Hydrogen peroxide-induced oxidative stress was performed using HDFs to measure intracellular ROS activity. Radical scavenging capacity was determined using a colorimetric antioxidant assay kit (ABTS method). Lastly, a 4-week, 29-subject study was performed in which SIG1273 was applied topically as a cream to assess its tolerance and activity in reducing the appearance of aging.

RESULTS

In vitro studies demonstrate SIG1273 inhibits UVA-induced MMP-1 production, hydrogen peroxide-induced oxidative stress and promotes wound healing. Moreover, SIG1273 was shown to be a radical scavenging antioxidant. Clinical assessment of SIG1273 cream (0.25%) showed it was well tolerated with significant improvement in the appearance of fine lines, coarse wrinkles, radiance/luminosity, pore size, texture/smoothness, hydration and increased firmness.

CONCLUSIONS

SIG1273 represents a novel CFI with antioxidant, anti-aging, and anti-inflammatory properties that when applied topically is well tolerated and provides benefits to individuals with aging skin.

Anti-aging cosmetics: facts and controversies

The authors review ageing in its extrinsic and intrinsic mechanisms, as well as the therapies available for improving its effects, and present some of the facts and controversies related to anti-aging cosmetics.

Enhancing structural support of the dermal microenvironment activates fibroblasts, endothelial cells, and keratinocytes in aged human skin in vivo

The dermal extracellular matrix (ECM) provides strength and resiliency to skin. The ECM consists mostly of type I collagen fibrils, which are produced by fibroblasts. Binding of fibroblasts to collagen fibrils generates mechanical forces, which regulate cellular morphology and function. With aging, collagen fragmentation reduces fibroblast-ECM binding and mechanical forces, resulting in fibroblast shrinkage and reduced function, including collagen production. Here, we report that these age-related alterations are largely reversed by enhancing the structural support of the ECM. Injection of dermal filler, cross-linked hyaluronic acid, into the skin of individuals over 70 years of age stimulates fibroblasts to produce type I collagen. This stimulation is associated with localized increase in mechanical forces, indicated by fibroblast elongation/spreading, and mediated by upregulation of type II TGF-β receptor and connective tissue growth factor. Interestingly, enhanced mechanical support of the ECM also stimulates fibroblast proliferation, expands vasculature, and increases epidermal thickness. Consistent with our observations in human skin, injection of filler into dermal equivalent cultures causes elongation of fibroblasts, coupled with type I collagen synthesis, which is dependent on the TGF-β signaling pathway. Thus, fibroblasts in aged human skin retain their capacity for functional activation, which is restored by enhancing structural support of the ECM.

Theories and management of aging: modern and ayurveda perspectives

Aging is a complex phenomenon, a sum total of changes that occur in a living organism with the passage of time and lead to decreasing ability to survive stress, increasing functional impairment and growing probability of death. There are many theories of aging and skin remains the largest organ of the study. Skin aging is described as a consequence of intrinsic and extrinsic factors. The most common amongst visible signs of skin aging are wrinkles and there are various therapies including antiaging cosmeceuticals, sunscreens, chemical peeling, injectable agents, such as botox, fibrel, autologous fat grafting as also few surgical procedures have been used. Ayurveda, the Indian traditional medicine, describes aging with great details. This review provides modern and Ayurvedic perspectives on theories and management of aging.

Wound healing activity of topical application forms based on ayurveda

The traditional Indian medicine-Ayurveda, describes various herbs, fats, oils and minerals with anti-aging as well as wound healing properties. With aging, numerous changes occur in skin, including decrease in tissue cell regeneration, decrease in collagen content, loss of skin elasticity and mechanical strength. We prepared five topical anti-aging formulations using cow ghee, flax seed oil, Phyllanthus emblica fruits, Shorea robusta resin, Yashada bhasma as study materials. For preliminary efficacy evaluation of the anti-aging activity we chose excision and incision wound healing animal models and studied the parameters including wound contraction, collagen content and skin breaking strength which in turn is indicative of the tissue cell regeneration capacity, collagenation capacity and mechanical strength of skin. The group treated with the formulations containing Yashada bhasma along with Shorea robusta resin and flax seed oil showed significantly better wound contraction (P < .01), higher collagen content (P < .05) and better skin breaking strength (P < .01) as compared to control group; thus proposing them to be effective prospective anti-aging formulations.

Percutaneous absorption and exposure assessment of pesticides

Dermal exposure to a diverse range of chemicals may result from various uses. In order to assess exposure and estimate potential risks, accurate quantitative data on absorption are required. Various factors will influence the final results and interpretations of studies designed to assess the ability of compounds to penetrate the skin. This overview will discuss skin penetration by pesticides, emphasizing key parameters to be considered from the perspective of exposure assessment.

Looking older: fibroblast collapse and therapeutic implications

Skin appearance is a primary indicator of age. During the last decade, substantial progress has been made toward understanding underlying mechanisms of human skin aging. This understanding provides the basis for current use and new development of antiaging treatments. Our objective is to review present state-of-the-art knowledge pertaining to mechanisms involved in skin aging, with specific focus on the dermal collagen matrix. A major feature of aged skin is fragmentation of the dermal collagen matrix. Fragmentation results from actions of specific enzymes (matrix metalloproteinases) and impairs the structural integrity of the dermis. Fibroblasts that produce and organize the collagen matrix cannot attach to fragmented collagen. Loss of attachment prevents fibroblasts from receiving mechanical information from their support, and they collapse. Stretch is critical for normal balanced production of collagen and collagen-degrading enzymes. In aged skin, collapsed fibroblasts produce low levels of collagen and high levels of collagen-degrading enzymes. This imbalance advances the aging process in a self-perpetuating, never-ending deleterious cycle. Clinically proven antiaging treatments such as topical retinoic acid, carbon dioxide laser resurfacing, and intradermal injection of cross-linked hyaluronic acid stimulate production of new, undamaged collagen. Attachment of fibroblasts to this new collagen allows stretch, which in turn balances collagen production and degradation and thereby slows the aging process. Collagen fragmentation is responsible for loss of structural integrity and impairment of fibroblast function in aged human skin. Treatments that stimulate production of new, nonfragmented collagen should provide substantial improvement to the appearance and health of aged skin.

[Use of biophysical techniques to evaluate the physiologic effects of injected hyaluronic acid]

BACKGROUND

To evaluate the effects of intradermal injection of native hyaluronic acid on physiology of aged skin using bioengineering methods.

PATIENTS AND METHODS

10 female patients aged 44-69 were included. Study duration was 24 weeks. Each patient received 3 treatments (at week 0, 2 and 4) with native hyaluronic acid (Hyalsystem Merz Pharmaceuticals, Frankfurt/Main, Germany) and 4 examinations (week 0, 4, 12 and 24). Biophysical properties assessed were skin elasticity and surface roughness, as well as skin thickness and density.

RESULTS

Skin elasticity increased while skin surface roughness was reduced. High frequency ultrasound revealed an increase of skin thickness, whereas skin density decreased during treatment and slightly increased above baseline at week 24.

CONCLUSION

The evaluation of the effects of an intradermal injection of hyaluronic acid on aged skin showed an improvement of skin elasticity and skin surface roughness.

Native hyaluronic acid in dermatology--results of an expert meeting

The glycosaminoglycan hyaluronic acid (HA) is a major component of the extracellular matrix of the skin and plays an important role in the metabolism of the dermis.HA is responsible for hydration,nutrient exchange and protects against free radical damage;via signaling pathways it is also involved in biologic processes like cell differentiation and motility. Native HA has been employed for several years to help the skin to regain elasticity,turgor and moisture. In a clinical study an increase in elasticity and turgor following repeated injections with HA could be demonstrated, but this treatment approach is discussed controversially. An expert conference took place to find a consensus regarding use, aims of treatment, indications and limitations of this therapy. The decisions of the expert meeting are presented in this report.

Changes associated with the aging face

The demand for facial plastic surgery has increased dramatically in recent years as persons from all socioeconomic levels and age groups have become interested in facial rejuvenation. As the population ages, the demand for esthetic surgery in the elderly will increase at an even greater rate. Before the surgeon begins to learn specific techniques in facial plastic surgery, he or she should have a thorough understanding of the anatomy of the aging face. Safe and effective esthetic surgery is possible only when the anatomic changes associated with the aging face are appreciated by the surgeon and patient.

Potent therapeutic effect of melatonin on aging skin in pinealectomized rats

It is generally agreed that one of the major contributors to skin aging is reactive oxygen species. As organisms reach advanced age, free radical generation increases and the activity of tissue antioxidant enzyme system decreases. Melatonin is an antioxidant and free radical scavenger. The present study was first aimed to determine the morphometric and biochemical changes caused by long-term pinealectomy in order to investigate the role of melatonin as skin architecture. Secondly, the effect of exogenous melatonin administration on these changes was determined. Rats were pinealectomized or sham operated (control) for 6 months. Half of the pinealectomized rats were treated with 4 mg/kg melatonin during the last month of the experiment. Pinealectomy resulted in important morphometric and biochemical changes in the back, abdominal and thoracic skin. The thickness of epidermis and dermis and the number of dermal papillae and hair follicles were reduced. Melatonin administration to pinealectomized rats significantly improved these alterations in all body areas (P < 0.005). On the contrary, in pinealectomized rats the levels of antioxidant enzymes, catalase and glutathione peroxidase were decreased. Melatonin restored the levels of these enzymes. The pinealectomy-induced increases in lipid peroxidation in the abdominal and thoracic skin were significantly reduced by melatonin treatment (P < 0.005 and 0.01 respectively). These results suggest that melatonin is highly efficient anti-aging factor and, as melatonin levels decrease with age, melatonin treatment may reduce age-related skin changes.

Nutrition 1: a vital consideration in the management of skin wounds

Nutrition is a provocative subject in tissue repair, particularly in relation to the skin which consists of many different tissues fulfilling various essential functions. This article, the first in a two-part series, will discuss the structure of the human skin and its variations, with indications as to the individual requirements of the cells in fulfilling their normal role in skin physiology and in repair systems. Nutrient gradients seem to play a major role in normal skin physiology and repair systems following injury. The second part will discuss in more detail the importance of major nutrient factors and their inter-relationships in tissue repair. It is clear that much of our available knowledge is derived from experimental studies in animals. Their relevance in human wound healing may be equivocal as the human skin is unique in the animal kingdom.

Junior A, Jamur MC, Pinto JA, Fomin DS. Estudo comparativo histológico na prega vocal após incisão com instrumental a frio e com laser de CO2 em modelo animal

Dentre os vários tipos de laser usados em Medicina, o laser de CO2 é o mais usado na Otorrinolaringologia e Cirurgia de Cabeça e Pescoço. As vantagens de seu uso são a diminuição do sangramento, a diminuição do edema no pós-operatório e a facilidade de acesso ao campo operatório, entre outras. Desde os trabalhos de Jako e Strong em 1972(1,2), quando o laser de CO2 passou a ser usado no tratamento de papilomatose laríngea e de lesões malignas glóticas iniciais, suas indicações têm aumetado, principalmente em lesões benignas, a partir da alta tecnologia desenvolvida dos últimos anos como, por exemplo, a diminuição do microspot e o uso do superpulso, reduzindo conseqüentemente seu efeito térmico sobre os tecidos. MÉTODOS: Neste trabalho foram realizadas incisões com instrumental a frio e com laser de CO2 1 watt de modo contínuo e superpulso, em pregas vocais caninas e observado, através de cortes histológicos corados pelo método de Sirius Red, a quantidade de colágeno depositada sobre as mesmas. RESULTADOS: A quantidade de colágeno das pregas vocais foi maior do que no grupo controle, e estatisticamente maior no grupo de animais submetidos a procedimentos com instrumental a frio do que com laser de CO2. Não houve diferença estatística entre o grupo controle e o grupo submetido a incisões com instrumentos a frio. CONCLUSÃO: A microcirurgia de laringe com o laser de CO2, quando este é usado em baixa potência, com pequeno "microspot" e com superpulso, é um método seguro em relação à deposição de colágeno, quando comparado com instrumentos com lâmina a frio, obedecendo os princípios da fonomicrocirurgia.

Determinants of skin sensitivity to solar irradiation

BACKGROUND

Acute effects of UV irradiation include UV-induced erythema. Sunlight plays an important role in the development of skin cancer. Several predictive factors of UV-induced erythema could also be predictive for skin cancer.

OBJECTIVE

Our objective was to quantitatively assess phenotypical and nutritional determinants of sensitivity to UV irradiation, as assessed by the minimal erythema dose (MED).

DESIGN

We conducted a cross-sectional study among 335 volunteers. Sensitivity to UV irradiation was established through assessment of the MED. Phenotypical determinants, including skin melanin content, hair color and iris color were determined by skin reflectance spectrometry, a subjective questionnaire and an objective classification system, respectively. Furthermore, dietary exposure was measured by carotenoids, vitamin C, retinol and alpha-tocopherol in serum.

RESULTS

Male subjects were found to be more sensitive to UV irradiation; that is, the MED was significantly lower compared to female subjects. Skin melanin content, which was positively associated with iris color in both sexes and with hair color in men, was the main phenotypical determinant of sensitivity to UV irradiation. No associations were found between serum carotenoids and MED in the total study group. Vitamin C was inversely associated with MED. However, associations between carotenoids concentrations and MED showed a positive trend in subjects with melanin values above and a negative trend in subjects below the median after adjustment for gender and total cholesterol.

CONCLUSIONS

Skin melanin content and gender are important determinants of sensitivity to UV irradiation. No relation was found between serum carotenoids and MED in the total study group. The inverse association between vitamin C and MED was against our hypothesis. For the modifying effect of melanin on the association between carotenoids and MED, we do not have a clear biological explanation.

High-dose long wave visible light induces perinuclear vacuolization in vivo but does not result in early photoageing and apoptosis

With the advancing widespread use of photodynamic therapy, questions have arisen about the necessity to protect the adjacent healthy skin from high-dose long-wave light. The aim of the present study was to investigate the effects of high dose visible light on the skin of healthy volunteers with focus on apoptosis, DNA damage, inflammation, melanogenesis and induction of matrix metalloproteinases (MMP). Fourteen healthy volunteers were included and irradiated daily on their buttocks with 1300 kJ/m2 long wave visible light (560-780 nm) on five consecutive days with a cumulative dose of 6500 kJ/m2. In each volunteer six biopsies were taken before and 24 h after irradiation on days 1, 2, 3 and 5 and on day 8 and 12. Frozen and paraffin sections were investigated by measuring parameters for photodamage (apoptosis, p53, phosphorylated c-Jun), skin ageing (phosphorylated c-Jun, MMP-1, elastin content) melanogenesis (Melan A). Although no sunburn cells were seen, a significant increase in perinuclear vacuolization was noted (P < 0.0003) from day 5 till 7 days after the last irradiation. There was no expression of phosphorylated c-Jun, whereas the expression of p53, Melan A, MMP-1 and elastin content did not change. High-dose visible light induces a significant increase in perinuclear vacuolization, but does not result in apoptosis, photodamage or early induction of skin ageing.

Estudo das alterações relacionadas com a idade na pele humana, utilizando métodos de histo-morfometria e autofluorescência

FUNDAMENTOS: O processo de envelhecimento tecidual é evidente nas modificações visíveis na pele, resultando em importantes implicações psicológicas para o indivíduo e crescente interesse científico. OBJETIVOS: O presente trabalho objetivou analisar as alterações da pele normal com o envelhecimento mediante estratégias de histomorfometria e autofluorescência. MÉTODOS: Foram coletadas amostras de pele do abdômen de 18 cadáveres, incluindo cinco indivíduos jovens (menos de 20 anos), sete indivíduos com idade intermediária (20-60 anos) e seis indivíduos idosos (mais de 60 anos). Foram feitos cortes histológicos em parafina seguidos de coloração pela Hematoxilina-Eosina (H&E) e pelo tricrômio de Van Gieson-elastina. Avaliaram-se a espessura da epiderme e derme, e a superfície de contato epidermo-dérmica. Investigaram-se ainda as modificações qualitativas do aparelho colágeno-elástico, considerando sua disposição espacial na derme. Espécimes corados em H&E também foram utilizados para autofluorescência. RESULTADOS: A espessura da epiderme e derme do grupo idoso foi significativamente diminuída (p<0,05) em relação aos demais grupos. Os grupos idoso e intermediário exibiram acentuada redução na superfície de contato epiderme-derme (p<0,05). Detectaram-se a perda da distribuição em rede das fibras elásticas com sua progressiva fragmentação, alterações da compactação do colágeno e espessamento da membrana basal com o envelhecimento. CONCLUSÃO: O envelhecimento leva à redução da espessura da derme e epiderme, bem como ao aplanamento da junção dermo-epidérmica. As mudanças da pele ao longo da vida nem sempre seguem um perfil linear, mostrando drásticas alterações nas últimas décadas de vida. O método de autofluorescência mostrou-se um instrumento valioso no estudo da complexa relação espacial das fibras elásticas e colágenas.

Vitamina C

Há muito o papel do ácido ascórbico (AA) no metabolismo do tecido conjuntivo tem sido reconhecido, sobretudo a partir do século 16, quando o escorbuto começou a ser prevenido com sumo de frutas cítricas. As primeiras publicações referentes ao uso tópico da vitamina C, inicialmente em cobaio, datam da década de 1960. Entretanto, só mais recentemente tem-se dado valor a essa via de aplicação. Os autores apresentam revisão sobre o assunto, discorrendo sobre o histórico da vitamina C, seus efeitos no metabolismo do tecido conjuntivo, no processo de cicatrização, sobre sua atividade antioxidante e mecanismos de ação.

Tensile stress-dependent collagen XII and fibronectin production by fibroblasts requires separate pathways

The intracellular mechanisms controlling mechano-dependent production of the two extracellular matrix proteins collagen XII and fibronectin were analyzed. Fibroblasts were cultured on either tensed (attached) or released (floating) collagen type-I gels, respectively. Collagen XII and fibronectin production was three- to fivefold higher under tensed than under released conditions. The general inhibitor of tyrosine phosphorylation, genistein (50 microM), and the MAP kinase inhibitor PD98059 (20 microM) selectively reduced collagen XII accumulation by tensed cultures. Addition of PD98059, but not genistein, downregulated tensile stress-induced tyrosine phosphorylation levels of ERK1/2 and focal adhesion kinase. Staurosporine as well as pretreatment with phorbol ester, which constitute means to downregulate classical and novel PKC activity, specifically blocked collagen XII but not fibronectin accumulation in tensed fibroblasts. ERK1/2 phosphorylation levels were not affected by staurosporine treatment. Chronic exposure to the protein kinase C inhibitors bisindolylmaleimide and calphostin C blocked increased production of both fibronectin and collagen XII from cells under tension. The data manifest that the mechano-dependent production of collagen XII and fibronectin requires separate pathways. The FAK-ERK1/2 pathway, a genistein-sensitive tyrosine kinase, and a distinct classical/novel PKC appear selectively required for increased production of collagen XII in cells under tensile stress, whereas fibronectin induction is regulated by a different PKC-dependent pathway.