Repair of photoaged dermal matrix by topical application of a cosmetic ‘antiageing’ product

Cosmetic retinoid use in photoaged skin: A review of the compounds, their use and mechanisms of action

The inevitable attrition of skin due to ultraviolet radiation, termed photoaging, can be partially restored by treatment with retinoid compounds. Photoaged skin in lightly pigmented individuals, clinically presents with the appearance of wrinkles, increased laxity, and hyper- and hypopigmentation. Underlying these visible signs of ageing are histological features such as epidermal thinning, dermal-epidermal junction flattening, solar elastosis and loss of the dermal fibrillin microfibrillar network, fibrillar collagen and glycosaminoglycans. Retinoid compounds are comprised of three main generations with the first generation (all-trans retinoic acid, retinol, retinaldehyde and retinyl esters) primarily used for the clinical and cosmetic treatment of photoaging, with varying degrees of efficacy, tolerance and stability. All-trans retinoic acid is considered the 'gold standard' for skin rejuvenation; however, it is a prescription-only product largely confined to clinical use. Therefore, retinoid derivatives are readily incorporated into cosmeceutical formulations. The literature reported in this review suggests that retinol, retinyl esters and retinaldehyde that are used in many cosmeceutical products, are efficacious, safe and well-tolerated. Once in the skin, retinoids utilize a complex signalling pathway that promotes remodelling of photoaged epidermis and dermis and leads to the improvement of the cutaneous signs of photoaging.

Retinoids in the treatment of photoageing: A histological study of topical retinoid efficacy in black skin

BACKGROUND

Photoageing describes complex cutaneous changes that occur due to chronic exposure to solar ultraviolet radiation (UVR). The 'gold standard' for the treatment of photoaged white skin is all-trans retinoic acid (ATRA); however, cosmetic retinol (ROL) has also proven efficacious. Recent work has identified that black skin is susceptible to photoageing, characterized by disintegration of fibrillin-rich microfibrils (FRMs) at the dermal-epidermal junction (DEJ). However, the impact of topical retinoids for repair of black skin has not been well investigated.

OBJECTIVES

To determine the potential of retinoids to repair photoaged black skin.

METHODS

An exploratory intervention study was performed using an in vivo, short-term patch test protocol. Healthy but photoaged black volunteers (>45 years) were recruited to the study, and participant extensor forearms were occluded with either 0.025% ATRA (n = 6; 4-day application due to irritancy) or ROL (12-day treatment protocol for a cosmetic) at concentrations of 0.3% (n = 6) or 1% (n = 6). Punch biopsies from occluded but untreated control sites and retinoid-treated sites were processed for histological analyses of epidermal characteristics, melanin distribution and dermal remodelling.

RESULTS

Treatment with ATRA and ROL induced significant acanthosis (all p < 0.001) accompanied by a significant increase in keratinocyte proliferation (Ki67; all p < 0.01), dispersal of epidermal melanin and restoration of the FRMs at the DEJ (all p < 0.01), compared to untreated control.

CONCLUSIONS

This study confirms that topical ATRA has utility for the repair of photoaged black skin and that ROL induces comparable effects on epidermal and dermal remodelling, albeit over a longer timeframe. The effects of topical retinoids on black photoaged skin are similar to those reported for white photoaged skin and suggest conserved biology in relation to repair of UVR-induced damage. Further investigation of topical retinoid efficacy in daily use is warranted for black skin.

Prediction, screening and characterization of novel bioactive tetrapeptide matrikines for skin rejuvenation

BACKGROUND

Extracellular matrices play a critical role in tissue structure and function and aberrant remodelling of these matrices is a hallmark of many age-related diseases. In skin, loss of dermal collagens and disorganization of elastic fibre components are key features of photoageing. Although the application of some small matrix-derived peptides to aged skin has been shown to beneficially affect in vitro cell behaviour and, in vivo, molecular architecture and clinical appearance, the discovery of new peptides has lacked a guiding hypothesis.

OBJECTIVES

To identify, using protease cleavage site prediction, novel putative matrikines with beneficial activities for skin composition and structure.

METHODS

Here, we present an in silico (peptide cleavage prediction) to in vitro (proteomic and transcriptomic activity testing in cultured human dermal fibroblasts) to in vivo (short-term patch test and longer-term split-face clinical study) discovery pipeline, which enables the identification and characterization of peptides with differential activities.

RESULTS

Using this pipeline we showed that cultured fibroblasts were responsive to all applied peptides, but their associated bioactivity was sequence-dependent. Based on bioactivity, toxicity and protein source, we further characterized a combination of two novel peptides, GPKG (glycine-proline-lysine-glycine) and LSVD (leucine-serine-valine-aspartate), that acted in vitro to enhance the transcription of matrix -organization and cell proliferation genes and in vivo (in a short-term patch test) to promote processes associated with epithelial and dermal maintenance and remodelling. Prolonged use of a formulation containing these peptides in a split-face clinical study led to significantly improved measures of crow's feet and firmness in a mixed population.

CONCLUSIONS

This approach to peptide discovery and testing can identify new synthetic matrikines, providing insights into biological mechanisms of tissue homeostasis and repair and new pathways to clinical intervention.

Melasma: A Step-by-Step Approach Towards a Multimodal Combination Therapy

Melasma is a common challenge in the field of pigmentary skin disorders, exerting a significant emotional and psychosocial burden on patients. The persistent and recurring nature of melasma complicates its management in routine clinical practice. This comprehensive review outlines a stepwise, practical approach encompassing diagnostic, preventive and therapeutic strategies for the management of melasma. A thorough exploration of aggravating and exacerbating factors, including sun exposure, hormonal imbalances, photosensitizing medication and cosmetics, is essential for a holistic assessment of the disease. With an emphasis on consistent and effective photoprotection, initial topical treatment modalities target the melanin production and/or the transfer of melanosomes to keratinocytes. Topical tyrosine inhibitors emerge as the first choice for reducing and preventing hyperpigmentation, with compounds such as thiamidol or tranexamic acid (TXA) being preferred for their safety profile over hydroquinone (HQ), kojic acid and arbutin. Combination with chemical peels can further enhance the therapeutic efficacy, even in cases with resistant melasma. In more severe cases, laser- and light-based interventions may be considered, but with the caveat of the likelihood of recurrence within 3-6 months. Assisted TXA delivery, via either fractional non-ablative laser or microneedling techniques, can further improve clinical outcomes. In conclusion, an optimal melasma management strategy is a multimodal approach, which includes effective photoprotection and a mix of different topical treatments targeting melanin synthesis, the anti-inflammatory environment, senescence and vascularity. Complementary procedures, such as chemical peels, and laser, light-based or microneedling procedures, with or without TXA, can further expedite melanin clearance in more severely affected instances. Individual discussions with patients regarding treatment expectations, recurrence likelihood and potential side effects are paramount to a comprehensive and successful therapeutic journey.

Antioxidant peptides, the guardian of life from oxidative stress

Reactive oxygen species (ROS) are produced during oxidative metabolism in aerobic organisms. Under normal conditions, ROS production and elimination are in a relatively balanced state. However, under internal or external environmental stress, such as high glucose levels or UV radiation, ROS production can increase significantly, leading to oxidative stress. Excess ROS production not only damages biomolecules but is also closely associated with the pathogenesis of many diseases, such as skin photoaging, diabetes, and cancer. Antioxidant peptides (AOPs) are naturally occurring or artificially designed peptides that can reduce the levels of ROS and other pro-oxidants, thus showing great potential in the treatment of oxidative stress-related diseases. In this review, we discussed ROS production and its role in inducing oxidative stress-related diseases in humans. Additionally, we discussed the sources, mechanism of action, and evaluation methods of AOPs and provided directions for future studies on AOPs.

Senotherapeutic peptide treatment reduces biological age and senescence burden in human skin models

Cellular senescence is known to play a role in age-related skin function deterioration which potentially influences longevity. Here, a two-step phenotypic screening was performed to identify senotherapeutic peptides, leading to the identification of Peptide (Pep) 14. Pep 14 effectively decreased human dermal fibroblast senescence burden induced by Hutchinson-Gilford Progeria Syndrome (HGPS), chronological aging, ultraviolet-B radiation (UVB), and etoposide treatment, without inducing significant toxicity. Pep 14 functions via modulation of PP2A, an understudied holoenzyme that promotes genomic stability and is involved in DNA repair and senescence pathways. At the single-cell level, Pep 14 modulates genes that prevent senescence progression by arresting the cell cycle and enhancing DNA repair, which consequently reduce the number of cells progressing to late senescence. When applied on aged ex vivo skin, Pep 14 promoted a healthy skin phenotype with structural and molecular resemblance to young ex vivo skin, decreased the expression of senescence markers, including SASP, and reduced the DNA methylation age. In summary, this work shows the safe reduction of the biological age of ex vivo human skins by a senomorphic peptide.

Multifaceted amelioration of cutaneous photoageing by (0.3%) retinol

BACKGROUND

Although retinol skin care products improve the appearance of photoaged skin, there is a need for an effective retinol concentration that provides skin benefits without irritation.

OBJECTIVE

To compare the efficacy of topical 0.1%, 0.3% and 1% retinol in remodelling the cutaneous architecture in an in vivo experimental patch test study, and to determine tolerance of the most effective formulations when used in a daily in-use escalation study.

METHODS

For the patch test study, retinol products were applied under occlusion, to the extensor forearm of photoaged volunteers (n = 5; age range 66-84 years), and 3 mm skin biopsies obtained after 12 days. Effects of different retinol concentrations, and a vehicle control, on key epidermal and dermal biomarkers of cellular proliferation and dermal remodelling were compared to untreated baseline. Separately, participants (n = 218) recorded their tolerance to 0.3% or 1% retinol over a six-week, approved regimen, which gradually increased the facial applications to once nightly.

RESULTS

Retinol treatment induced a stepwise increase in epidermal thickness and induced the expression of stratum corneum proteins, filaggrin and KPRP. 0.3% retinol and 1% retinol were comparably effective at inducing keratinocyte proliferation in the epidermis, whilst reducing e-cadherin expression. Fibrillin-rich microfibril deposition was increased following treatment with 0.3% and 1% retinol (p < 0.01); other dermal components remained unaltered (e.g., fibronectin, collagen fibrils, elastin), and no evidence of local inflammation was detected. The in-use study found that 0.3% retinol was better tolerated than 1% retinol, with fewer and milder adverse events reported (χ² (1) = 23.97; p < 0.001).

CONCLUSIONS

This study suggests that 1% and 0.3% retinol concentrations were similarly effective at remodelling photodamaged skin in an in vivo model of long-term use. Use of 0.3% retinol in the escalation study was associated with fewer adverse reactions when applied daily. Hence, 0.3% retinol may be better tolerated than 1% retinol, thereby allowing longer-term topical application.

Stability and Applicability of Retinyl Palmitate Loaded Beeswax Microcapsules for Cosmetic Use : Material properties and stability of microencapsulated actives

In our previous study, retinyl palmitate was successfully encapsulated by melt dispersion using waxes as shell materials. Herein, the objective of the present research is to evaluate the shelf life and kinetic release of the developed microcapsules. The study was conducted by measuring actual loading capacity over a period of time using spectroscopic analysis. The transfer percentage of particles from nonwoven facial wipes to skin-like surfaces was also investigated by simulating the rubbing mechanism with a robotic transfer replicator. Although particles stored as powder form under room temperature showed only eight days of shelf-life, particles stored as a dispersion in a refrigerator maintained 60% of the theoretical loading capacity after one month. The kinetic release profile of the particles in ethanol with shaking at 100 rpm and 37±2°C showed an initial burst in the first half an hour, followed by a sustained release. It also showed that 98% of the retinyl palmitate content released within 4 h. Particles incorporated into wet nonwoven wipes gave approximately 22% transfer to skin-like fabric. Thus, the study shows potentials of delivering skincare properties by means of retinyl palmitate capsule loaded textile substrates.

Matrikines as mediators of tissue remodelling

Extracellular matrix (ECM) proteins confer biomechanical properties, maintain cell phenotype and mediate tissue repair (via release of sequestered cytokines and proteases). In contrast to intracellular proteomes, where proteins are monitored and replaced over short time periods, many ECM proteins function for years (decades in humans) without replacement. The longevity of abundant ECM proteins, such as collagen I and elastin, leaves them vulnerable to damage accumulation and their host organs prone to chronic, age-related diseases. However, ECM protein fragmentation can potentially produce peptide cytokines (matrikines) which may exacerbate and/or ameliorate age- and disease-related ECM remodelling. In this review, we discuss ECM composition, function and degradation and highlight examples of endogenous matrikines. We then critically and comprehensively analyse published studies of matrix-derived peptides used as topical skin treatments, before considering the potential for improvements in the discovery and delivery of novel matrix-derived peptides to skin and internal organs. From this, we conclude that while the translational impact of matrix-derived peptide therapeutics is evident, the mechanisms of action of these peptides are poorly defined. Further, well-designed, multimodal studies are required.

Ultrasonographic Assessment of the Cutaneous Changes Induced by Topical Use of Novel Peptides Comprising Laminin 5

Background  Laminin 5, which is found in the basement membrane of dermal-epidermal junction (DEJ), is a major adhesive component and associated with proliferating and migrating keratinocytes. In this study, we hypothesized that the topical application of the skin care products containing the novel peptides might restore the DEJ structure by deriving deposition of laminin 5 and promoting the keratinocyte migration. Here, we evaluated the restoration of DEJ by measuring the skin thickness.

Methods  Single-center retrospective analysis was performed on a total of 13 patients who underwent skin care using Baume L.C.E. (France, Laboratories d' Anjou) between January and March 2021. All patients applied the skin care agent for 2 weeks only on their left hand dorsum. Before the initiation of the application and after 2 weeks, both their hands were evaluated on photography and ultrasound. And the patients were asked to rate their satisfaction with the questionnaire after 2 weeks.

Results  There was no obvious improvement in photographic assessment and questionnaire. The post–pre difference of skin thickness in ultrasound images was, in left hand, 0.1 ± 0.37 in distal point and 0.1 ± 0.35 in proximal point; and, in right hand, 0 ± 0.17 in distal point and 0 ± 0.15 in proximal point, respectively. The pre–post difference was statistically significant in proximal point ( p  = 0.035).

Conclusion  Topical application of novel peptide derivative comprising laminin 5 demonstrated cutaneous changes including skin thickness, as assessed by ultrasound. Further studies using other modalities including dermal density measurement, three-dimensional photography, optical coherence tomography, or skin biopsy would be helpful to determine the skin-improving effects.

Cosmeceuticals: The Principles and Practice of Skin Rejuvenation by Nonprescription Topical Therapy

Background

Aesthetic practice relies on a harmonious relationship between medicine and commerce. Bridging the gap is a large number of skincare products that make therapeutic claims while avoiding the regulatory framework of pharmaceuticals. In this gray area, clinicians find themselves poorly disposed to counsel patients wisely as the industry is expanding faster than empirical evidence of efficacy and safety can be acquired. To serve our patients and engage with industry, we must understand the theoretical principles and evaluate the clinical evidence in practice.

Objectives

The purpose of this paper is to classify cosmeceuticals by method of action, explain how they work in principle with reference to skin aging, and evaluate the clinical evidence for them.

Methods

A literature and cosmetic clinic website search was conducted to establish a list of the most commonly advertised cosmeceuticals, and a peer-reviewed literature search was then conducted to establish the clinical evidence for them.

Results

A huge number of cosmeceuticals are marketed for skin rejuvenation but almost invariably they fall into 1 of 4 categories. These include the induction of tissue repair mechanisms, inflammatory modulation, scavenging of reactive oxygen species, or a combination of the 3. With the exception of retinol derivatives and hydroxy acids, the clinical evidence is limited, despite promising preclinical evidence for several cosmeceuticals.

Conclusions

Cosmeceuticals reside within a highly competitive ecosystem and are often brought to market based on preclinical, not clinical evidence. Success and failure will largely be governed by the establishment of clinical evidence in retrospect.

The top 10 cosmeceuticals for facial hyperpigmentation

Disorders of facial hyperpigmentation including melasma, postinflammatory hyperpigmentation and solar lentigines are common cutaneous conditions which can have a huge impact on patients' quality of life and often prove difficult to treat. The nascent market of cosmeceutical options provides a potentially safer and efficacious alternative for treating these challenging conditions. These can be used alone or in combination with other established treatments. Many cosmeceutical products are thought to work through inhibition of tyrosinase, a key enzyme of melanogenesis. We discuss the mode of action and provide an up-to-date review of the underlying evidence base for the top 10 cosmeceutical products for hyperpigmentation and melasma. Possible safer and more efficacious cosmeceutical therapies we discuss include thiamidol, kojic acid, vitamin C, arbutin, retinol, nicotinamide, ferulic acid, resorcinol, licorice root extract, and soy.

The systemic influence of chronic smoking on skin structure and mechanical function

One of the major functions of human skin is to provide protection from the environment. Although we cannot entirely avoid, for example, sun exposure, it is likely that exposure to other environmental factors could affect cutaneous function. A number of studies have identified smoking as one such factor that leads to both facial wrinkle formation and a decline in skin function. In addition to the direct physical effects of tobacco smoke on skin, its inhalation has additional profound systemic effects for the smoker. The adverse effects on the respiratory and cardiovascular systems from smoking are well known. Central to the pathological changes associated with smoking is the elastic fibre, a key component of the extracellular matrices of lungs. In this study we examined the systemic effect of chronic smoking (>40 cigarettes/day; >5 years) on the histology of the cutaneous elastic fibre system, the nanostructure and mechanics of one of its key components, the fibrillin-rich microfibril, and the micromechanical stiffness of the dermis and epidermis. We show that photoprotected skin of chronic smokers exhibits significant remodelling of the elastic fibre network (both elastin and fibrillin-rich microfibrils) as compared to the skin of age- and sex-matched non-smokers. This remodelling is not associated with increased gelatinase activity (as identified by in situ zymography). Histological remodelling is accompanied by significant ultrastructural changes to extracted fibrillin-rich microfibrils. Finally, using scanning acoustic microscopy, we demonstrated that chronic smoking significantly increases the stiffness of both the dermis and the epidermis. Taken together, these data suggest an unappreciated systemic effect of chronic inhalation of tobacco smoke on the cutaneous elastic fibre network. Such changes may in part underlie the skin wrinkling and loss of skin elasticity associated with smoking. © 2020 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.

Tissue-Engineered Vascular Grafts with Advanced Mechanical Strength from Human iPSCs

Vascular smooth muscle cells (VSMCs) can be derived in large numbers from human induced pluripotent stem cells (hiPSCs) for producing tissue-engineered vascular grafts (TEVGs). However, hiPSC-derived TEVGs are hampered by low mechanical strength and significant radial dilation after implantation. Here, we report generation of hiPSC-derived TEVGs with mechanical strength comparable to native vessels used in arterial bypass grafts by utilizing biodegradable scaffolds, incremental pulsatile stretching, and optimal culture conditions. Following implantation into a rat aortic model, hiPSC-derived TEVGs show excellent patency without luminal dilation and effectively maintain mechanical and contractile function. This study provides a foundation for future production of non-immunogenic, cellularized hiPSC-derived TEVGs composed of allogenic vascular cells, potentially serving needs to a considerable number of patients whose dysfunctional vascular cells preclude TEVG generation via other methods.

Photoaging Skin Therapy with PRP and ADSC: A Comparative Study

BACKGROUND

Stem cells from adipose tissue (ADSCs) and platelet-rich plasma (PRP) are innovative modalities that arise due to their regenerative potential.

OBJECTIVE

The aim of this study was to characterize possible histological changes induced by PRP and ADSC therapies in photoaged skin.

METHODS

A prospective randomized study involving 20 healthy individuals, showing skin aging. They underwent two therapeutic protocols (protocol 1: PRP; protocol 2: ADSCs). Biopsies were obtained before and after treatment (4 months).

RESULTS

PRP protocol showed unwanted changes in the reticular dermis, mainly due to the deposition of a horizontal layer of collagen (fibrosis) and elastic fibers tightly linked. Structural analyses revealed infiltration of mononuclear cells and depot of fibrotic material in the reticular dermis. The ADSC protocol leads to neoelastogenesis with increase of tropoelastin and fibrillin. There was an improvement of solar elastosis inducing an increment of macrophage polarization and matrix proteinases. These last effects are probably related to the increase of elastinolysis and the remodeling of the dermis.

CONCLUSIONS

The PRP promoted an inflammatory process with an increase of reticular dermis thickness with a fibrotic aspect. On the other hand, ADSC therapy is a promising modality with an important antiaging effect on photoaged human skin.

Theophylline exerts complex anti-ageing and anti-cytotoxicity effects in human skin ex vivo

OBJECTIVE

Theophylline is a phosphodiesterase inhibitor that is being used clinically for asthma therapy. In addition, it is recognized as a cosmetic agent with possible anti-ageing and anti-oxidative properties. Nevertheless, how it affects human skin is still poorly examined.

METHODS

Theophylline (10 or 100 µM) was administered to the culture medium of full-thickness human skin ex vivo for 24 or 72 h.

RESULTS

Theophylline stimulated protein expression of the anti-oxidant metallothionein-1 and mRNA levels of collagen I and III. Assessment of fibrillin-1 immunohistology revealed enhanced structural stability of dermal microfibrils. Theophylline also exerted extracellular matrix-protective effects by decreasing MMP-2 and MMP-9 mRNA levels, partially antagonizing the effects of menadione, the potent, toxic ROS donor. In addition, it decreased menadione-stimulated epidermal keratinocytes apoptosis. Interestingly, theophylline also increased the level of intracutaneously produced melatonin, that is the most potent ROS-protective and DNA damage repair neuromediator, and tendentially increased protein expression of MT1, the melatonin receptor. Theophylline also increased the expression of keratin 15, the stem cell marker, in the epidermal basal layer but did not change mitochondrial activity or epidermal pigmentation.

CONCLUSION

This ex vivo pilot study in human skin shows that theophylline possesses several interesting complex skin-protective properties. It encourages further examination of theophylline as a topical candidate for anti-ageing treatment.

Circadian rhythms in skin and other elastic tissues

Circadian rhythms are daily oscillations that, in mammals, are driven by both a master clock, located in the brain, and peripheral clocks in cells and tissues. Approximately 10% of the transcriptome, including extracellular matrix components, is estimated to be under circadian control. Whilst it has been established that certain collagens and extracellular matrix proteases are diurnally regulated (for example in tendon, cartilage and intervertebral disc) the role played by circadian rhythms in mediating elastic fiber homeostasis is poorly understood. Skin, arteries and lungs are dynamic, resilient, elastic fiber-rich organs and tissues. In skin, circadian rhythms influence cell migration and proliferation, wound healing and susceptibility of the tissues to damage (from protease activity, oxidative stress and ultraviolet radiation). In the cardiovascular system, blood pressure and heart rate also follow age-dependent circadian rhythms whilst the lungs exhibit diurnal variations in immune response. In order to better understand these processes it will be necessary to characterise diurnal changes in extracellular matrix biology. In particular, given the sensitivity of peripheral clocks to external factors, the timed delivery of interventions (chronotherapy) has the potential to significantly improve the efficacy of treatments designed to repair and regenerate damaged cutaneous, vascular and pulmonary tissues.

Oral Intake of Low-Molecular-Weight Collagen Peptide Improves Hydration, Elasticity, and Wrinkling in Human Skin: A Randomized, Double-Blind, Placebo-Controlled Study

Collagen-peptide supplementation could be an effective remedy to improve hydration, elasticity, and wrinkling in human skin. The aim of this study was to conduct a double-blind, randomized, placebo-controlled trial to clinically evaluate the effect on human skin hydration, wrinkling, and elasticity of Low-molecular-weight Collagen peptide (LMWCP) with a tripetide (Gly-X-Y) content >15% including 3% Gly-Pro-Hyp. Individuals (n = 64) were randomly assigned to receive either placebo or 1000 mg of LMWCP once daily for 12 weeks. Parameters of skin hydration, wrinkling, and elasticity were assessed at baseline and after 6 weeks and 12 weeks. Compared with the placebo group, skin-hydration values were significantly higher in the LMWCP group after 6 weeks and 12 weeks. After 12 weeks in the LMWCP group, visual assessment score and three parameters of skin wrinkling were significantly improved compared with the placebo group. In case of skin elasticity, one parameter out of three was significantly improved in the LMWCP group from the baseline after 12 weeks, while, compared with the placebo group, two parameters out of three in the LMWCP group were higher with significance after 12 weeks. In terms of the safety of LMWCP, none of the subjects presented adverse symptoms related to the test material during the study period. These results suggest that LMWCP can be used as a health functional food ingredient to improve human skin hydration, elasticity, and wrinkling.

Photo-co-carcinogenesis of Topically Applied Retinyl Palmitate in SKH-1 Hairless Mice

Cosmetic products that contain retinyl palmitate are popular as antiaging skin treatments; however, recent studies suggest a risk for enhanced skin tumor development with topical retinyl palmitate applications and exposure to solar ultraviolet radiation (UVR). In this study, we investigated the potential of retinyl palmitate to enhance UVR-induced photo-co-carcinogenesis. Groups of 36 male and 36 female SKH-1 hairless mice were exposed to simulated solar light (SSL) and treated with the control cream or creams containing retinyl palmitate, 5 days per week for 40 weeks. Other groups of mice were exposed to SSL and received no cream treatment or received cream treatments and were exposed to ultraviolet-A or ultraviolet-B. Mice were monitored for the development of skin tumors, and the incidences and multiplicities of squamous cell neoplasia were determined by histopathology. In both the absence and presence of SSL, mice administered the control cream developed skin tumors earlier and had higher incidences and multiplicities of skin squamous cell neoplasms than mice that received no cream treatment. Compared to the control cream groups, mice exposed to SSL and administered the retinyl palmitate creams demonstrated earlier onsets of skin tumors and had increased incidences and multiplicities of squamous cell skin neoplasms.

Ability of sodium copper chlorophyllin complex to repair photoaged skin by stimulation of biomarkers in human extracellular matrix

PURPOSE

To examine the effect of sodium copper chlorophyllin complex on the expression of biomarkers of photoaged dermal extracellular matrix indicative of skin repair.

PATIENTS AND METHODS

Following a previously published 12-day clinical assessment model, skin biopsy samples from the forearms of four healthy females with signs of photoaged skin were obtained and samples were analyzed by immunohistochemistry for key biomarkers of aging skin after each subject was treated with a test material consisting of a gel containing a liposomal dispersion of sodium copper chlorophyllin complex 0.05%, a positive control of tretinoin cream 0.025%, and an untreated negative control.

RESULTS

There was a statistically significantly greater amount of fibrillin/amyloid P and epidermal mucins found for skin treated with the test material containing 0.05% sodium copper chlorophyllin complex and the reference control tretinoin 0.025% cream compared to the negative control (untreated site). Expression of procollagen 1 and dermal mucin also showed a greater presence in the samples treated with the test material and the reference control compared to the negative control, though the differences were not statistically significant. No adverse events were observed or reported by the subjects during the course of the study.

CONCLUSION

The results of this human biopsy study suggest that both retinoids and sodium copper chlorophyllin complex have beneficial effects on biomarkers of photoaged skin. Products containing both sodium copper chlorophyllin complex and retinols may provide a dual approach to reversing age-related decreases in hyaluronic acid (HA) in the skin: inhibition of the breakdown of HA via sodium copper chlorophyllin complex by inhibition of hyaluronidase, and stimulation of HA synthases by retinol.

Thyroid Hormones Enhance Mitochondrial Function in Human Epidermis

Since it is unknown whether thyroid hormones (THs) regulate mitochondrial function in human epidermis, we treated organ-cultured human skin, or isolated cultured human epidermal keratinocytes, with triiodothyronine (100 pmol/L) or thyroxine (100 nmol/L). Both THs significantly increased protein expression of the mitochondrially encoded cytochrome C oxidase I (MTCO1), complex I activity, and the number of perinuclear mitochondria. Triiodothyronine also increased mitochondrial transcription factor A (TFAM) protein expression, and thyroxine stimulated complex II/IV activity. Increased mitochondrial function can correlate with increased reactive oxygen species production, DNA damage, and accelerated tissue aging. However, THs neither raised reactive oxygen species production or matrix metalloproteinase-1, -2 and -9 activity nor decreased sirtuin1 (Sirt1) immunoreactivity. Instead, triiodothyronine increased sirtuin-1, fibrillin-1, proliferator-activated receptor-gamma 1-alpha (PGC1α), collagen I and III transcription, and thyroxine decreased cyclin-dependent kinase inhibitor 2A (p16(ink4)) expression in organ-cultured human skin. Moreover, TH treatment increased intracutaneous fibrillin-rich microfibril and collagen III deposition and decreased mammalian target of rapamycin (mTORC1/2) expression ex vivo. This identifies THs as potent endocrine stimulators of mitochondrial function in human epidermis, which down-regulates rather than enhance the expression of skin aging-related biomarkers ex vivo. Therefore, topically applied THs deserve further exploration as candidate agents for treating skin conditions characterized by reduced mitochondrial function.

Topical Products for the Aging Face

This article focuses on nonprescription home-use topical treatment technologies for the aging face and is intended to serve as a guide for the core cosmeceutical technologies currently used and to help educate and assist the selection of topical antiaging products by the professional staff and their patients. Antiaging topical treatments for patient home use should be nonirritating, compatible with the patient skin type, effective, and complementary to surgical and minimally invasive office procedures, and aesthetically elegant. New topical antiaging technologies, formulated as monotherapy or as combinations with well-known cosmeceuticals, should present adequate clinical studies to support their selection for use.

A new wrinkle on old skin: the role of elastic fibres in skin ageing

Cutaneous ageing is the result of two distinct, biological processes which may occur concurrently: (i) the passage of time, termed intrinsic ageing and (ii) environmental influences, termed extrinsic ageing. Intrinsic ageing of the skin is a slow process which causes changes in tissue structure and impairs function in the absence of additional biological, chemical and physical factors. The clinical features of intrinsically aged skin are not usually evident until old age when, although smooth and unblemished, the skin surface appears pale and is characterized by fine wrinkles with occasional exaggerated expression lines. Functionally, intrinsically aged skin is dry and less elastic than more youthful skin. In contrast, extrinsically aged skin is exemplified by deep, coarse wrinkles, mottled hyperpigmentation and a marked loss of elasticity and recoil. The two major environmental influences which induce extrinsic ageing are: (i) chronic exposure to solar ultraviolet (UV) irradiation (termed photoageing) and (ii) smoking. This review discusses the changes associated with the ageing process in the skin, with particular emphasis on the role played by the elastic fibre network in maintaining dermal function. The review concludes with a discussion of a short-term assay for independent assessment of the efficacy of anti-ageing cosmetic products using the elastic fibre component fibrillin-1 as a biomarker of extracellular matrix repair.

Compounds leached from quinoa seeds inhibit matrix metalloproteinase activity and intracellular reactive oxygen species

OBJECTIVE

Quinoa (Chenopodium quinoa Willd.) is a seed crop rich in bioactive compounds including phytoecdysones (especially 20-hydroxyecdysone, 20HE), polyphenols, proteins and essential fatty acids. We previously reported a method to leach and concentrate quinoa bioactives into a complex phytochemical mixture termed quinoa leachate (QL). Here, we aimed to determine the effect of QL and its chemically distinct fractions on five biochemical endpoints relevant to skin care applications: (i) cell viability, (ii) matrix metalloproteinase (MMP) mRNA expression, (iii) MMP enzymatic activity, (iv) tyrosinase enzymatic activity and (v) intracellular reactive oxygen species (ROS) production.

METHODS

Quinoa leachate was fractionated and chemically characterized using column chromatography and liquid chromatography-mass spectrometry (LC-MS). Cell viability was determined using a MTT assay in four mammalian cell lines. MMP-1 mRNA expression was assessed in human dermal fibroblasts (HDF) via qRT-PCR. The enzymatic activity of MMP-9 and tyrosinase was measured using fluorometric and colorimetric in vitro assays, respectively. Lipopolysaccharide (LPS)-induced ROS production was determined in human dermal fibroblasts by fluorescence intensity of an oxidant-sensitive probe.

RESULTS

Quinoa leachate was separated into three fractions: (i) carbohydrate-rich fraction (QL-C; 71.3% w/w of QL); (ii) phytoecdysone, polyphenol and protein-rich fraction (QL-P, 13.3% w/w of QL); (iii) oil-rich fraction (QL-O, 10.8% w/w of QL). QL did not reduce cell viability in any of the four cell lines tested. QL, QL-P and QL-O each significantly inhibited MMP-1 mRNA expression in HDF at a concentration of 5 μg mL(-1) . QL and QL-P also significantly inhibited MMP-9 enzymatic activity, whereas QL-P demonstrated significant tyrosinase enzymatic inhibition. Furthermore, QL, QL-P, QL-O and 20HE significantly inhibited intracellular ROS production.

CONCLUSION

This study is the first to demonstrate the MMP, tyrosinase and ROS inhibiting properties of multiple different phytochemical components derived from quinoa seeds. Our work indicates that quinoa phytochemicals may play a role in the treatment and prevention of skin ageing through a multiplicity of effects.

Enhanced In Vitro Skin Deposition Properties of Retinyl Palmitate through Its Stabilization by Pectin

The purpose of this study was to examine the effect of stabilization of retinyl palmitate (RP) on its skin permeation and distribution profiles. Skin permeation and distribution study were performed using Franz diffusion cells along with rat dorsal skin, and the effect of drug concentration and the addition of pectin on skin deposition profiles of RP was observed. The skin distribution of RP increased in a concentration dependent manner and the formulations containing 0.5 and 1 mg of pectin demonstrated significantly increased RP distributions in the epidermis. Furthermore, it was found that skin distribution of RP could be further improved by combined use of pectin and ascorbyl palmitate (AP), due largely to their anti-oxidative effect. These results clearly demonstrate that the skin deposition properties of RP can be improved by stabilizing RP with pectin. Therefore, it is strongly suggested that pectin could be used in the pharmaceutical and cosmetic formulations as an efficient stabilizing agent and as skin penetration modulator.

In vitro and in vivo studies with tetra-hydro-jasmonic acid (LR2412) reveal its potential to correct signs of skin ageing

BACKGROUND

LR2412, a synthetic derivative of jasmonic acid, improved the reconstruction and homeostasis of our organotypic skin models.

OBJECTIVES

The need for efficient 'anti-ageing' treatments, in particular for the management of photoaged skin, prompted us to investigate this new ingredient for its potential to correct signs of skin ageing in vitro and in vivo and to identify its mode of action.

RESULTS

In vitro, penetration of LR2412 was evaluated using a Franz diffusion cell on excised human skin. Its exfoliating properties and interactions with the stratum corneum were studied using electron microscopy and X-ray diffraction. Experiments were performed on a human reconstructed skin model. In vivo, the effects of LR2412 on steroid-induced skin atrophy, a clinical skin ageing model, were assessed vs. vehicle. A patch test study evaluated its effect on deposition of fibrillin-rich microfibrils in the papillary dermis in clinically photoaged volunteers. A clinical study on the appearance of crow's feet wrinkles was conducted over 3 months of daily application. Penetration studies revealed that LR2412 reaches viable epidermis and superficial dermis, which are skin targets of anti-ageing actives. Within the upper layers of the stratum corneum LR2412 accelerates desquamation and improves the mechanical properties. At the dermal-epidermal junction of reconstructed skin, collagen IV, laminin-5 and fibrillin were stimulated. In vivo, LR2412 reversed steroid-induced atrophy. The patch test model confirms the deposition of fibrillin-rich microfibrils, then an in use clinical study revealed that it reduced facial wrinkles.

CONCLUSIONS

The in vitro and in vivo data demonstrate that based on its multiple interactions within human skin, LR2412 has potential to partially correct the signs of ageing in intrinsically and photoaged skin.

Amentoflavone inhibits UVB-induced matrix metalloproteinase-1 expression through the modulation of AP-1 components in normal human fibroblasts

Amentoflavone is a well-known biflavonoid that has diverse biological effects. Previously, we reported that amentoflavone suppressed UVB-induced matrix metalloproteinase-1 (MMP-1) expression in normal human fibroblasts (NHF). We investigated the effects of amentoflavone on UVB-induced MMP-1 expression in order to elucidate its mode of action. NHF were treated with amentoflavone for indicated times and doses with UVB irradiation. The expressions of MMP-1 gene and protein were determined by RT-PCR and ELISA, respectively. MAP kinase phosphorylation and the expression of c-Fos protein were determined by Western blot. The treatment of amentoflavone completely blocked the upregulation of MMP-1 which is induced by UVB irradiation in HaCaT-NHF co-culture in a dose-dependent manner as well as in NHF monoculture. Also, amentoflavone inhibited UVB-induced activation of extracellular signal-regulated kinase (ERK) without changing total ERK protein level, and did not affect p38 or JNK activation. Finally, AP-1 transcription factor components, phospho-c-Jun and c-Fos protein expressions were decreased by amentoflavone treatment. The major finding of this study shows that amentoflavone inhibits intracellular cell signaling ERK pathway leading to the prevention of MMP-1 expression in human skin fibroblasts. Therefore, these results strongly suggest that amentoflavone should be investigated as a potential agent for the prevention and the treatment of skin photoaging.

Topically applied KTTKS: a review

Skin ageing is an irreversible process that is caused by both intrinsic and extrinsic factors. The possibility of arresting or delaying skin ageing represents a large research area and has a big potential in the cosmetics sector. Recently, the polypeptide lysine-threonine-threonine-lysine-serine (KTTKS) has attracted a lot of attention and it features in numerous up-market cosmetic products where it has become erroneously associated with the term 'pentapeptide'. In this study, we review in detail KTTKS and its major derivatives, in terms of the limited information in the literature and an appraisal of its physicochemical and theoretical skin permeation properties. There appears to be a sound in vitro basis for its action on fibroblasts due to its stimulatory effect on extracellular matrix synthesis, where the stimulatory effect of KTTKS is specific to collagen types I and III and fibronectin expression. However, there is a surprising absence of in vitro skin penetration data in the literature, and there are relatively few clinical studies using these materials.

Novel vitamin and gold-loaded nanofiber facial mask for topical delivery

L-ascorbic acid has been widely used in cosmetic and dermatological products because of its ability to scavenge free radicals and destroy oxidizing agents. However, it is chemically unstable and can easily be oxidized. The current cosmetic facial masks available in the market are pre-moistened, which means that the aqueous fluid content of the mask may oxidize some of the unstable active ingredients such as ascorbic acid. This work presents an anti-wrinkle nanofiber face mask containing ascorbic acid, retinoic acid, gold nanoparticles, and collagen. This novel face mask will only be wetted when applied to the skin, thus enhancing product stability. Once moistened, the content of the mask will gradually dissolve and release the active ingredients and ensure maximum skin penetration. The high surface area-to-volume ratio of the nanofiber mask will ensure maximum contact with the skin surface and help to enhance the skin permeation to restore its healthy appearance. Electrospun fiber mats may provide an attractive alternative to the commercial facial cotton masks.

Cosmeceuticals: the evidence behind the retinoids

A wide range of cosmeceutical products are available on the market currently, but evidence to support their use is often lacking in the literature. Specifically, there is a substantial amount of evidence supporting the efficacy of tretinoin in photoaging, but the evidence supporting retinoid-based cosmeceuticals remains sparse. The authors review the current data in the literature related to vitamin A-derived cosmeceutical products and conclude that cosmeceuticals containing retinaldehyde have been shown in large randomized, controlled trials to have the most beneficial effect on aging skin.

Tissue elasticity and the ageing elastic fibre

The ability of elastic tissues to deform under physiological forces and to subsequently release stored energy to drive passive recoil is vital to the function of many dynamic tissues. Within vertebrates, elastic fibres allow arteries and lungs to expand and contract, thus controlling variations in blood pressure and returning the pulmonary system to a resting state. Elastic fibres are composite structures composed of a cross-linked elastin core and an outer layer of fibrillin microfibrils. These two components perform distinct roles; elastin stores energy and drives passive recoil, whilst fibrillin microfibrils direct elastogenesis, mediate cell signalling, maintain tissue homeostasis via TGFβ sequestration and potentially act to reinforce the elastic fibre. In many tissues reduced elasticity, as a result of compromised elastic fibre function, becomes increasingly prevalent with age and contributes significantly to the burden of human morbidity and mortality. This review considers how the unique molecular structure, tissue distribution and longevity of elastic fibres pre-disposes these abundant extracellular matrix structures to the accumulation of damage in ageing dermal, pulmonary and vascular tissues. As compromised elasticity is a common feature of ageing dynamic tissues, the development of strategies to prevent, limit or reverse this loss of function will play a key role in reducing age-related morbidity and mortality.

Effects of a cosmetic 'anti-ageing' product improves photoaged skin [corrected]

Background

Very few over-the-counter cosmetic ‘anti-ageing’ products have been subjected to a rigorous double-blind, vehicle-controlled trial of efficacy. Previously we have shown that application of a cosmetic ‘anti-ageing’ product to photoaged skin under occlusion for 12 days can stimulate the deposition of fibrillin-1. This observation infers potential to repair and perhaps clinically improve photoaged skin.

Objective

We examined another similar over-the-counter cosmetic ‘anti-ageing’ product using both the patch test assay and a 6-month double-blind, randomized controlled trial (RCT), with a further 6-month open phase to assess clinical efficacy in photoaged skin.

Methods

For the patch test, a commercially available test product and its vehicle were applied occluded for 12 days to photoaged forearm skin (n=10) prior to biopsy and immunohistochemical assessment of fibrillin-1; all-trans retinoic acid (RA) was used as a positive control. Sixty photoaged subjects were recruited to the RCT (test product, n = 30 vs. vehicle, n = 30; once daily for 6 months, face and hands) with clinical assessments performed at recruitment and following 1, 3 and 6 months of use. Twenty-eight volunteers had skin biopsies (dorsal wrist) at baseline and at 6 months treatment for immunohistochemical assessment of fibrillin-1 (test product, n=15; vehicle, n=13). All volunteers received the test product for a further 6 months. Final clinical assessments were performed at the end of this open period.

Results

In the 12-day patch test assay, we observed significant immunohistological deposition of fibrillin-1 in skin treated with the test product and RA compared with the untreated baseline (P=0·005 and 0·015, respectively). In the clinical RCT, at 6 months, the test product produced statistically significant improvement in facial wrinkles as compared to baseline assessment (P = 0·013), whereas vehicle-treated skin was not significantly improved (P = 0·11). After 12 months, there was a significant benefit of the test product over that projected for the vehicle (70% vs. 33% of subjects improving; combined Wilcoxon rank tests, P=0·026). There was significant deposition of fibrillin-1 in skin treated for 6 months with the test product [(mean ± SE) vehicle 1·84 ± 0·23; test product 2·57 ± 0·19; ancovaP=0·019).

Conclusions

In a double-blind RCT, an over-the-counter cosmetic ‘anti-ageing’ product resulted in significant clinical improvement in facial wrinkles, which was associated with fibrillin-1 deposition in treated skin. This study demonstrates that a cosmetic product can produce significant improvement in the appearance of wrinkles and further supports the use of fibrillin-1 as a robust biomarker for the repair of photoaged dermis.

Comparison of epidermal morphologic response to commercial antiwrinkle agents in the hairless mouse

BACKGROUND

A large number of commercial antiwrinkle and antiaging compounds are available to consumers for rejuvenation of facial skin ravaged by age or solar radiation. Experimental data on the histological effects of these commercial products in laboratory models are sparse.

OBJECTIVES

To compare the efficacy of topical application of five commercially available antiaging compounds (retinoic acid, glycolic acid, vitamin C, estrogen, and soy) on the dorsal skin.

METHODS AND MATERIALS

The effects were examined using light microscopic analysis of the epidermis in the normal nonirradiated hairless mouse. The agents were applied daily to dorsal tattooed areas for 2 weeks before histological assessment; neighboring untreated surface areas were used as control. Morphometric measurements of total epidermal width, nuclear volume of keratinocytes in three layers, and index of proliferating cell nuclear antigen according to immunohistochemistry were obtained and statistically analyzed.

RESULTS

Significant histomorphometric effects were noticed with all five agents, but more pronounced changes were obtained with glycolic acid, estrogen, and retinoic acid product.

CONCLUSIONS

These baseline data will be useful for future studies on the effect of ultraviolet radiation to cause photoaging and reparative effects of similar agents in this animal. The information contained in the report may provide guidelines to consumers and clinicians.