The effects of a novel synthetic retinoid, seletinoid G, on the expression of extracellular matrix proteins in aged human skin in vivo

Cosmetic application of the stem-bark extract of Bertholletia excelsa H.B.K

OBJECTIVE

The Amazon has a rich biodiversity where many different plant species can be found. This diversity is an important source of bioactive substances, mainly due to the different structural components of their phytometabolites. Research for natural products is a strategy for the development of new agents in therapeutic applications, especially cosmetic applications, that have better pharmacological potential. Within this perspective, the objective of the study was to investigate the cosmetic application (anti-aging potential) of the stem-bark extract of Bertholletia excelsa H.B.K - (SBEBE), popularly known as the Brazil nut tree, here called SBEBE, a noble plant species of the Amazon that is rich in selenium.

METHODS

Enzymatic, glycation, proliferation, cell-healing, collagen quantification, toxicity and genotoxicity assays were used.

RESULTS

Among the enzymes involved in the extracellular matrix of the skin, SBEBE was able to inhibit only elastase (62.67 ± 3.75) when compared to the standard sivelestat (89.04 ± 0.53), and the extract was also able to inhibit both the oxidative and the non-oxidative pathway. When cell toxicity in fibroblasts (MRC-5) and keratinocytes (HACAT) was evaluated, SBEBE did not present toxicity in 24 h of incubation. After this period, the extract showed average cytotoxicity in 48 and 72 h, but not enough to reach the concentration of 50% of MRC-5 fibroblasts. In the trypan blue assay, the extract promoted fibroblast proliferation in 24, 48 and 72 h of incubation, which was evaluated through exponential cell growth, with emphasis mainly on the lowest concentration with results higher than the standard. When the cell healing capacity was evaluated, in 48 h of exposure to fibroblast, SBEBE was able to induce a cell carpet (cell film) in the cell monolayer scratch assay.

CONCLUSIONS

SBEBE stimulated collagen production at all concentrations tested. In the alkaline comet assay, at the lowest concentration, the extract did not induce DNA damage when compared to the reference drug doxorubicin. This study proved that SBEBE extract can be considered an ally in the treatment of skin anti-ageing as a possible biotechnological, phytocosmetic product.

Topical retinoids: Novel derivatives, nano lipid-based carriers, and combinations to improve chemical instability and skin irritation

BACKGROUND

Retinoids, defined as synthetic or natural derivatives of vitamin A, have been extensively studied as anti-aging molecules that are widely applied in cosmetics. However, due to their physicochemical property, retinoids are highly unstable and extremely sensitive to light, oxygen, and temperature. Moreover, topical application of retinoids often leads to cutaneous irritation. These instabilities and irritant properties of retinoids limit their application in cosmetic and pharmaceutical products.

AIM

Our study aimed to provide a systematic review to summarize the mechanisms underlying the instability and irritant properties of retinoids, as well as recent developments in addressing these challenges.

METHODS

A comprehensive PubMed search was conducted using the following keywords: retinoids, chemical instability, skin irritation, retinoid derivatives, nano lipid-based carriers, liposomes, penetration-enhancer vesicles, ethosomes, niosomes, nanoemulsions, solid lipid nanoparticles, vitamins, soothing and hydrating agents, antioxidants and metal chelator and retinol combinations. Relevant researches published between 1968 and 2023 and studies related to these reports were reviewed.

RESULTS

The development of new retinoid derivatives, the utilization of new delivery systems like nano lipid-based carriers and the combination with other compounds like vitamins, soothing agents, antioxidants and metal chelator have been explored to improve the stability, bioavailability, and toxicity of the retinoid family.

CONCLUSIONS

Through advancements in formulation techniques, structure modification of retinoid derivatives and development of novel nano lipid-based carriers, the chemical instability and skin irritation of retinoids has been mitigated, ensuring their efficacy and potency over extended periods.

Attempts to Improve Lipophilic Drugs' Solubility and Bioavailability: A Focus on Fenretinide

The development of numerous drugs is often arrested at clinical testing stages, due to their unfavorable biopharmaceutical characteristics. It is the case of fenretinide (4-HPR), a second-generation retinoid, that demonstrated promising in vitro cytotoxic activity against several cancer cell lines. Unfortunately, response rates in early clinical trials with 4-HPR did not confirm the in vitro findings, mainly due to the low bioavailability of the oral capsular formulation that was initially developed. Capsular 4-HPR provided variable and insufficient drug plasma levels attributable to the high hepatic first-pass effect and poor drug water solubility. To improve 4-HPR bioavailability, several approaches have been put forward and tested in preclinical and early-phase clinical trials, demonstrating generally improved plasma levels and minimal systemic toxicities, but also modest antitumor efficacy. The challenge is thus currently still far from being met. To redirect the diminished interest of pharmaceutical companies toward 4-HPR and promote its further clinical development, this manuscript reviewed the attempts made so far by researchers to enhance 4-HPR bioavailability. A comparison of the available data was performed, and future directions were proposed.

Durability of the improvement of collagen I and collagen III with the use of oral isotretinoin in the treatment of photoaging

BACKGROUND

Oral isotretinoin (ISO) is the drug of choice for the treatment of severe acne. For photoaging treatment, ISO has been proved to be effective in some controlled and noncontrolled trials and is an alternative to topical retinoic acid (RA) therapy, which causes an expected skin irritation.

OBJECTIVE

To evaluate and compare the skin remodeling in patients taking ISO 20 mg 3 times a week for 12 weeks and 12 weeks after the end of the treatment to quantify collagen I and collagen III augmentation.

MATERIAL AND METHODS

Immunohistochemical studies were performed to evaluate the expression of collagen I and collagen III, metalloproteinases (MMPs) -1, -3, -7, -9, -12, and the tissue inhibitor of MMP type-1 (TIMP-1) of the skin of 20 45 to 50-year-old women through morphometry in a semiquantitative method. The inclusion criteria were facial aging 2 and 3 of Glogau's classification, with phototypes between II and V who had not entered menopause. Biopsies of the skin of the left preauricular region were performed at three different times: pre-treatment (T0), end of 12-week treatment (T1), and 12 weeks posttreatment (T2).

RESULTS

Collagen fibers I and III increased with statistical significance in T1 (50.7%; P = 0.012) but not in T2 (49.7%), which in turn was higher than in T0 (47.2%) for collagen I and T1 (33.3%; P = 0.002) but not in T2 (32.7%), and also was higher than T0 (32.0%) for collagen III. MMP-9 presented a decreased activity with statistical significance in T1 (P = 0.047) and T2 (P = 0.058). MMP-1 showed a reduction in T2 only (P = 0.015). MMPs -3, -7, -12, and TIMP-1 did not present significant modification in their expressions during or after the treatment.

CONCLUSIONS

Low-dose ISO is effective in remodeling the extracellular matrix (ECM). This study found that the increase of collagen occurs through the augmentation of both collagen I and collagen III fibers. With originality, it was possible to verify the durability of these fibers for at least 12 weeks. This may be related to the decrease in MMP-9 expression verified at the end of the treatment and 12 weeks posttreatment.

The Potential Anti-Photoaging Effect of Photodynamic Therapy Using Chlorin e6-Curcumin Conjugate in UVB-Irradiated Fibroblasts and Hairless Mice

Photodynamic therapy (PDT) has been used to treat cancers and non-malignant skin diseases. In this study, a chlorin e6–curcumin conjugate (Ce6-PEG-Cur), a combination of chlorin e6 (Ce6) and curcumin via a PEG linker, was used as a photosensitizer. The in vitro and in vivo effects of PDT using Ce6-PEG-Cur were analyzed in UVB-irradiated fibroblasts and hairless mice. The UVB-induced expression of MMPs was reduced in Hs68 fibroblast cells, and procollagen type Ⅰ expression was enhanced by Ce6-PEG-Cur-mediated PDT on a Western blotting gel. Moreover, UVB-induced collagen levels were restored upon application of Ce6-PEG-Cur-mediated PDT. Ce6-PEG-Cur-mediated PDT inhibited the expression of phosphorylated p38 in the MAPK signaling pathway, and it reduced the expression of phosphorylated NF-κB. In animal models, Ce6-PEG-Cur-mediated PDT inhibited the expression of MMPs, whereas procollagen type Ⅰ levels were enhanced in the dorsal skin of UVB-irradiated mice. Moreover, UVB-induced dorsal roughness was significantly reduced following Ce6-PEG-Cur-mediated PDT treatment. H&E staining and Masson’s trichrome staining showed that the thickness of the epidermal region was reduced, and the density of collagen fibers increased. Taken together, Ce6-PEG-Cur-mediated PDT might delay and improve skin photoaging by ultraviolet light, suggesting its potential for use as a more effective photo-aging treatment.

Use of Retinoids in Topical Antiaging Treatments: A Focused Review of Clinical Evidence for Conventional and Nanoformulations

Nowadays, numerous skincare routines are used to rejuvenate aging skin. Retinoids are one of the most popular ingredients used in antiaging treatments. Among the representatives of retinoids, tretinoin is considered the most effective agent with proven antiaging effects on the skin and can be found in formulations approved as medicines for topical treatment of acne, facial wrinkles, and hyperpigmentation. Other retinoids present in topical medicines are used for various indications, but only tazarotene is also approved as adjunctive agent for treatment of facial fine wrinkling and pigmentation. The most commonly used retinoids such as retinol, retinaldehyde, and retinyl palmitate are contained in cosmeceuticals regulated as cosmetics. Since clinical efficacy studies are not required for marketing cosmetic formulations, there are concerns about the efficacy of these retinoids. From a formulation perspective, retinoids pose a challenge to researchers as a result of their proven instability, low penetration, and potential for skin irritation. Therefore, novel delivery systems based on nanotechnology are being developed to overcome the limitations of conventional formulations and improve user compliance. In this review, the clinical evidence for retinoids in conventional and nanoformulations for topical antiaging treatments was evaluated. In addition, an overview of the comparison clinical trials between tretinoin and other retinoids is presented. In general, there is a lack of evidence from properly designed clinical trials to support the claimed efficacy of the most commonly used retinoids as antiaging agents in cosmeceuticals. Of the other retinoids contained in medicines, tazarotene and adapalene have clinically evaluated antiaging effects compared to tretinoin and may be considered as potential alternatives for antiaging treatments. The promising potential of retinoid nanoformulations requires a more comprehensive evaluation with additional studies to support the preliminary findings.

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.

Recent Advances Regarding the Therapeutic Potential of Adapalene

Adapalene (ADP) is a representative of the third retinoids generation and successfully used in first-line acne treatment. ADP binds to retinoic acid nuclear receptors. The comedolytic, anti-inflammatory, antiproliferative, and immunomodulatory are the known ADP effects. Its safety profile is an advantage over other retinoids. ADP recently was found to be effective in the treatment of several dermatological diseases and photoaging besides the utility in the treatment of acne vulgaris. New biological effects of adapalene with therapeutic potential are highlighted in this review paper. Thus, adapalene could be a valuable therapeutic drug into the treatment of several types of cancer. Additionally, some neurodegenerative diseases could be treated with a suitable formulation for intravenous administration. The antibacterial activity against methicillin-resistant Staphylococcus aureus of an analogue of ADP has been proven. In different therapeutic schemes, ADP is more effective in combination with other active substances. New topical combinations with adapalene include ketoconazole (antifungal), mometasone furoate (anti-inflammatory corticosteroid), nadifloxacin (fluoroquinolone), and alfa and beta hydroxy acids. Combination with oral drugs is a new trend that enhances the properties of topical formulations with adapalene. Several studies have investigated the effects of ADP in co-administration with azithromycin, doxycycline, faropenem, isotretinoin, and valganciclovir. Innovative formulations of ADP also aim to achieve a better bioavailability, increased efficacy, and reduced side effects. In this review, we have highlighted the current studies on adapalene regarding biological effects useful in various treatment types. Adapalene has not been exploited yet to its full biological potential.

Synthetic Retinoid Seletinoid G Improves Skin Barrier Function through Wound Healing and Collagen Realignment in Human Skin Equivalents

The outer epidermal skin is a primary barrier that protects the body from extrinsic factors, such as ultraviolet (UV) radiation, chemicals and pollutants. The complete epithelialization of a wound by keratinocytes is essential for restoring the barrier function of the skin. However, age-related alterations predispose the elderly to impaired wound healing. Therefore, wound-healing efficacy could be also considered as a potent function of an anti-aging reagent. Here, we examine the epidermal wound-healing efficacy of the fourth-generation retinoid, seletinoid G, using HaCaT keratinocytes and skin tissues. We found that seletinoid G promoted the proliferation and migration of keratinocytes in scratch assays and time-lapse imaging. It also increased the gene expression levels of several keratinocyte proliferation-regulating factors. In human skin equivalents, seletinoid G accelerated epidermal wound closure, as assessed using optical coherence tomography (OCT) imaging. Moreover, second harmonic generation (SHG) imaging revealed that seletinoid G recovered the reduced dermal collagen deposition seen in ultraviolet B (UVB)-irradiated human skin equivalents. Taken together, these results indicate that seletinoid G protects the skin barrier by accelerating wound healing in the epidermis and by repairing collagen deficiency in the dermis. Thus, seletinoid G could be a potent anti-aging agent for protecting the skin barrier.

Kojyl Cinnamate Ester Derivatives Increase Adiponectin Expression and Stimulate Adiponectin-Induced Hair Growth Factors in Human Dermal Papilla Cells

Adiponectin (APN), released mainly from adipose tissue, is a well-known homeostatic factor for regulating glucose levels, lipid metabolism, and insulin sensitivity. A recent study showed that human hair follicles express APN receptors and the presence of APN-mediated hair growth signaling, thereby suggesting that APN is a potent hair growth-promoting adipokine. Previously, kojyl cinnamate ester derivatives (KCEDs) were synthesized in our institute as new anti-aging or adiponectin-/adipogenesis-inducing compounds. Here, we tested the activity of these derivatives to induce endogenous APN secretion. Among the derivatives, KCED-1 and KCED-2 showed improved activity in inducing APN mRNA expression, secretion of APN protein, and adipogenesis in human subcutaneous fat cells (hSCFs) when compared with the effects of Seletinoid G, a verified APN inducer. When human follicular dermal papilla cells were treated with the culture supernatant of KCED-1- or KCED-2-treated hSCFs, the mRNA expression of APN-induced hair growth factors such as insulin-like growth factor, hepatocyte growth factor, and vascular endothelial growth factor was upregulated compared with that in the control. Taken together, our study shows that among kojyl cinnamate ester derivatives, KCED-1, KCED-2, as well as Seletinoid G are effective inducers of endogenous APN production in subcutaneous fat tissues, which may in turn contribute to the promotion of hair growth in the human scalp.

Protection against UVB-induced damages in human dermal fibroblasts: efficacy of tricin isolated from enzyme-treated Zizania latifolia extract

This study was undertaken to determine the effects of enzyme-treated Zizania latifolia (ETZL) and of its major compound tricin on skin photo-aging and to investigate the mechanisms involved. It was found ETZL and tricin suppressed matrix metalloproteinase (MMP) production and increased type I-procollagen production in UVB-irradiated human dermal fibroblasts (HDFs). Furthermore, ETZL and tricin significantly up-regulated the expressions of the antioxidant enzymes HO-1 and SOD1, reduced UVB-induced reactive oxygen species (ROS) generation and mitogen-activated protein kinase (MAPK) induction by ROS and thereby attenuated activator protein-1 (AP-1) expression. In addition, ETZL and tricin both reduced the phosphorylations of IκBα and IKKα/ß and κB blocked the nuclear translocation of nuclear factor-κB (NF-κB) p65. These results show that ETZL have skin protective effects against UVB and suggest tricin as major efficacious material in ETZL protecting skin photoaging.

Kojyl cinnamate esters are peroxisome proliferator-activated receptor α/γ dual agonists

Adiponectin is an adipocytokine with insulin-sensitizing, anti-inflammatory, anti-atherosclerotic, and anti-aging properties. Compounds with the ability to promote adiponectin secretion are of interest for the development of anti-aging drugs to improve skin-aging phenotypes. In the phenotypic assay to measure adiponectin secretion during adipogenesis in human adipose tissue-derived mesenchymal stem cells (hAT-MSCs), kojyl cinnamate ester derivatives increased adiponectin secretion. A target identification study showed that the kojyl cinnamate ester derivatives competitively bound to peroxisome proliferator-activated receptor α/γ (PPARα/γ). The upregulation of adiponectin production induced by kojyl cinnamate ester derivatives was significantly correlated with PPARα and PPARγ binding activities. Kojyl cinnamate ester derivatives significantly increased the transcription of genes encoding cholesterol and fatty acid synthesizing enzymes in hAT-MSCs. Notably, the kojyl cinnamate esters upregulated the gene transcription of lipid metabolic enzymes in human epidermal keratinocytes, which are important in the integrity of skin permeability barrier. In addition, the kojyl cinnamate esters that function as PPARα/γ dual modulators inhibited ultraviolet B irradiation-induced inflammation in human epidermal keratinocytes. Therefore, kojyl cinnamate ester derivatives are a novel class of PPARα/γ dual agonists with the potential to improve skin-aging phenotypes.

Biological Activities and Cytotoxicity of Eperua oleifera Ducke Oil-resin

Background

The oil-resin of Eperua oleifera Ducke has been used in popular medicine similarly to the copaiba oil (Copaifera spp.).

Objective

This study aimed to investigate the effects of the acid fraction of E. oleifera oil-resin (AFEOR) on cell proliferation, collagen production in human fibroblasts, inhibition of metalloproteinases, and cytotoxicity against tumor cell lines.

Materials and Methods

Acid fraction of E. oleifera was fractionated in the ion exchange column chromatography. Cytotoxicity and genotoxicity were evaluated by Alamar Blue^® and Cometa assay. The inhibition of metalloproteinases was performed by zymography and Western blotting.

Results

The predominant acidic diterpenes in the AFEOR were copalic and hardwickiic acids. AFEOR caused morphology alteration and decrease of proliferation at concentrations higher than 5 μg/mL. It also caused significant collagen proliferation in fibroblasts. It showed cytotoxicity against tumoral and nontumoral cell lines, with IC₅₀ values ranging from 13 to 50 μg/mL, and a hemolytic activity with an IC₅₀ value of 38.29 μg/mL. AFEOR inhibited collagenase activity, with an IC₅₀ value of 46.64 μg/mL, and matrix metalloproteinase-2 (MMP)-2 and MMP-9 in HaCaT cells or MMP-1 expression in MRC-5 cells. AFEOR induced genotoxicity in MRC-5 cells with a DNA damage index between 40% and 60% when compared to the negative controls (0%-20%).

Conclusion

For the first time, biological activities from oil-resin E. oleifera demonstrated ratifying somehow its popular use.

SUMMARY

Analysis of crude oil-resin and fractionation of diterpenic fraction was performance using selective ion-exchange column chromatographyCytotoxicity analysis and morphology were performed with different cell linesCollagen production in human fibroblasts, inhibition of metalloproteinases were demonstrated by zymography and Western blotting. Abbreviations used: AFEOR: Eperua oleifera oil-resin.

Anti-Photoaging Effects of Angelica acutiloba Root Ethanol Extract in Human Dermal Fibroblasts

The effects that ultraviolet rays elicit on collagen synthesis and degradation are the most common causes of wrinkle formation and photo-aging in skin. The objectives of this study were to evaluate the effects of Angelica acutiloba root ethanol extract (AAEE) to promote collagen synthesis and inhibit collagen degradation in human dermal fibroblasts. By examining total polyphenol and flavonoid contents, electron donating ability, radical scavenging activity, and superoxide dismutase-like activity, we found that AAEE exhibited fairly good antioxidant activity. Treatment with AAEE significantly increased type I procollagen production by cultured fibroblasts, as well as reduced ultraviolet-induced matrix metalloproteinase-1 (MMP-1) expression and MMP-2 activity in a dose-dependent manner (p < 0.05). In addition, AAEE significantly increased TIMP-1 mRNA expression (p < 0.05), although without an associated dose-dependent increase in TIMP-1 protein expression. In summary, we suggest that AAEE may be a potentially effective agent for the prevention or alleviation of skin-wrinkle formation induced by ultraviolet rays.

Molecular mechanisms of green tea polyphenols with protective effects against skin photoaging

Whereas green tea has historically been consumed in high quantities in Northeast Asia, its popularity is also increasing in many Western countries. Green tea is an abundant source of plant polyphenols exhibiting numerous effects that are potentially beneficial for human health. Accumulating evidence suggests that green tea polyphenols confer protective effects on the skin against ultraviolet (UV) irradiation-induced acceleration of skin aging, involving antimelanogenic, antiwrinkle, antioxidant, and anti-inflammatory effects as well as prevention of immunosuppression. Melanin pigmentation in the skin is a major defense mechanism against UV irradiation, but pigmentation abnormalities such as melasma, freckles, senile lentigines, and other forms of melanin hyperpigmentation can also cause serious health and aesthetic issues. Furthermore, UV irradiation initiates the degradation of fibrillar collagen and elastic fibers, promoting the process of skin aging through deep wrinkle formation and loss of tissue elasticity. UV irradiation-induced formation of free radicals also contributes to accelerated photoaging. Additionally, immunosuppression caused by UV irradiation plays an important role in photoaging and skin carcinogenesis. In this review, we summarize the current literature regarding the antimelanogenic, antiwrinkle, antioxidant, and immunosuppression preventive mechanisms of green tea polyphenols that have been demonstrated to protect against UV irradiation-stimulated skin photoaging, and gauge the quality of evidence supporting the need for clinical studies using green tea polyphenols as anti-photoaging agents in novel cosmeceuticals.

Neocollagenesis and Neoelastinogenesis: From the Laboratory to the Clinic

An internet search was made looking for articles about chemical and physical modalities that are known to induce collagen and elastin formation. Textbooks, independent articles, journals and books on pathology, biochemistry, aesthetic medicine and cosmetic and plastic surgery were used as references. Here, we take a look at various studies, in vitro and in vivo, that lend credence to the products and procedures used in clinical practice to induce neocollagenesis and neoelastinogenesis.

Topical Retinoids: Therapeutic Mechanisms in the Treatment of Photodamaged Skin

Retinoids are a group of substances comprising vitamin A and its natural and synthetic derivatives. Retinoids were first used in dermatology in 1943 by Straumfjord for acne vulgaris. Since that time, retinoids have been utilized in the management and treatment of various skin conditions, including photoaging. Photodamage of the skin occurs as a consequence of cumulative exposure to solar ultraviolet radiation (UVR) and is characterized by deep wrinkles, easy bruising, inelasticity, mottled pigmentation, roughness, and telangiectasias. The mechanism of UVR-induced photodamage is multifactorial. Retinoids have demonstrated efficacy in the treatment of photoaged skin. Indeed, understanding the pathophysiology of photoaging and the molecular mechanism of retinoids can not only provide insight into the effects retinoids can exert in treating photoaging but also provide the rationale for their use in the treatment of other dermatologic diseases.

Nanoemulsions (NEs), liposomes (LPs) and solid lipid nanoparticles (SLNs) for retinyl palmitate: effect on skin permeation

The aim of this study was to develop biocompatible lipid-based nanocarriers for retinyl palmitate (RP) to improve its skin delivery, photostability and biocompatibility, and to avoid undesirable topical side effects. RP loaded nanoemulsions (NEs), liposomes (LPs) and solid lipid nanoparticles (SLNs) were characterized in terms of size, surface electrical charge, pH, drug encapsulation efficiency and morphology. Spherical-shaped nanocarriers with a negatively charged surface (>|40|mV) and mean size lower than 275 nm were produced with adequate skin compatibility. The rheological properties showed that aqueous dispersions of SLNs followed a non-Newtonian behavior, pseudoplastic fluid adjusted to Herschel-Bulkley equation, whereas LPs and NEs exhibited a Newtonian behavior. SLNs offered significantly better photoprotection than LPs and NEs for RP. The cumulative amount of drug permeated through human skin at the end of 38 h was 6.67 ± 1.58 μg, 4.36 ± 0.21 μg and 3.64 ± 0.28 μg for NEs, LPs and SLNs, respectively. NEs flux was significantly higher than SLNs and LPs: NEs (0.37 ± 0.12 μg/h) > LPs (0.15 ± 0.09 μg/h) > SLNs (0.10 ± 0.05 μg/h). LPs offered significant higher skin retention than NEs and SLNs. Finally, even though all developed nanocarriers were found to be biocompatible, according to histological studies, NE was the system that most disrupted the skin. These encouraging findings can guide in proper selection of topical carriers among the diversity of available lipid-based nanocarriers, especially when a dermatologic or cosmetic purpose is desired.

Kojyl cinnamate ester derivatives promote adiponectin production during adipogenesis in human adipose tissue-derived mesenchymal stem cells

The subcutaneous fat tissue mass gradually decreases with age, and its regulation is a strategy to develop anti-aging compounds to ameliorate the photo-aging of human skin. The adipogenesis of human adipose tissue-mesenchymal stem cells (hAT-MSCs) can be used as a model to discover novel anti-aging compounds. Cinnamomum cassia methanol extracts were identified as adipogenesis-promoting agents by natural product library screening. Cinnamates, the major chemical components of Cinnamomum cassia extracts, promoted adipogenesis in hAT-MSCs. We synthesized kojyl cinnamate ester derivatives to improve the pharmacological activity of cinnamates. Structure-activity studies of kojyl cinnamate derivatives showed that both the α,β-unsaturated carbonyl ester group and the kojic acid moiety play core roles in promoting adiponectin production during adipogenesis in hAT-MSCs. We conclude that kojyl cinnamate ester derivatives provide novel pharmacophores that can regulate adipogenesis in hAT-MSCs.

A retinyl palmitate-loaded solid lipid nanoparticle system: effect of surface modification with dicetyl phosphate on skin permeation in vitro and anti-wrinkle effect in vivo

Surface-modified solid lipid nanoparticles (SLNs) containing retinyl palmitate (Rpal) were prepared by the hot-melt method using Gelucire 50/13(®) and Precirol ATO5(®). Dicetyl phosphate (DCP) was added to negatively charge the surfaces of the SLNs and thereby enhance the skin distribution properties of Rpal. In vitro skin permeation and in vivo anti-aging studies were performed using SLNs dispersed in a hydrogel. The SLNs were under 100 nm in size with an even polydispersity index (PDI), and the high absolute zeta-potential value was sufficient to maintain the colloidal stability of the SLNs. DCP-modified negative SLNs (DCPmod-SLNs) enhanced the skin distribution of Rpal 4.8-fold and delivered Rpal to a greater depth than did neutral SLNs. The in vivo anti-wrinkle effect of the DCPmod-SLN formulation was Rpal dose-dependent. However, the anti-wrinkle effects of the DCPmod-SLN formulations were significantly different from that of the negative control and effectively prevented the reduction of elastin and superoxide dismutase by UV irradiation. In conclusion, the DCPmod-SLN system presented is a good candidate for topical Rpal delivery.

Photo-damage protective effect of two facial products, containing a unique complex of Dead Sea minerals and Himalayan actives

BACKGROUND

Skin appearance is badly affected when exposed to solar UV rays, which encourage physiological and structural cutaneous alterations that eventually lead to skin photo-damage.

AIMS

To test the capability of two facial preparations, extreme day cream (EXD) and extreme night treatment (EXN), containing a unique complex of Dead Sea water and three Himalayan extracts, to antagonize biological effects induced by photo-damage.

METHODS

Pieces of organ cultures of human skin were used as a model to assess the biological effects of UVB irradiation and the protective effect of topical application of two Extreme preparations. Skin pieces were analyzed for mitochondrial activity by MTT assay, for apoptosis by caspase 3 assay, and for cytokine secretion by solid phase ELISA. Human subjects were tested to evaluate the effect of Extreme preparations on skin wrinkle depth using PRIMOS and skin hydration by a corneometer.

RESULTS

UVB irradiation induced cell apoptosis in the epidermis of skin organ cultures and increased their pro-inflammatory cytokine, tumor necrosis α (TNFα) secretion. Topical applications of both preparations significantly attenuated all these effects. Furthermore, in human subjects, a reduction in wrinkle depth and an elevation in the intense skin moisture were observed.

CONCLUSIONS

The observations clearly show that EXD and EXN preparations have protective anti-apoptotic and anti-inflammatory properties that can attenuate biological effects of skin photo-damage. Topical application of the preparations improves skin appearance by reducing its wrinkles depth and increasing its moisturizing impact.

Cultivated ginseng suppresses ultraviolet B-induced collagenase activation via mitogen-activated protein kinases and nuclear factor κB/activator protein-1-dependent signaling in human dermal fibroblasts

Cultivated ginseng (CG) (Panax ginseng C.A. Meyer), an herb used in Korean herbal medicine, has been widely used in China and Japan to treat fatigue and to enhance resistance to many diseases. It contains many bioactive constituents, including various ginsenosides that are believed to have antioxidant, immunostimulatory, and antiaging activities. Previous studies have revealed that treatment with Panax ginseng is significantly associated with reduced photoaging, but the underlying mode of action has not been elucidated. In this study, we hypothesized that CG inhibits ultraviolet B (UVB)-induced collagenase activation through mitogen-activated protein kinases (MAPKs) and nuclear factor κB (NF-κB)/activator protein-1 (AP-1)-dependent signaling in human skin fibroblasts. HS68 cells were treated with CG, followed by irradiation with UVB. Those effects were assessed by semiquantitative polymerase chain reaction, Western blotting, and enzymic activity assays. We found that CG increased cell viability and inhibited the production of reactive oxygen species in HS68 cells exposed to UVB irradiation. Pretreatment of HS68 cells with CG inhibited UVB-induced production of matrix metalloproteinase (MMP) 1 and MMP-13. Western blot analysis further revealed that CG markedly suppressed the enhancement of collagen degradation in UVB-exposed HS68 cells. Cultivated ginseng also suppressed UVB-induced activation of NF-κB, c-Jun, and c-Fos and the phosphorylation of MAPKs, which are upstream modulators of NF-κB and AP-1. These results indicate that CG inhibits UVB-induced collagenolytic MMP production by interfering with MAPK/AP-1 and NF-κB signaling and thus may be useful in the prevention and treatment of skin photoaging.

Chitooligosaccharides attenuate UVB-induced damages in human dermal fibroblasts

As a continuation of our research on chitooligosaccharides (COS), this study focused on the protective effect of COS of various molecular weights (1-3, 3-5, and 5-10 kDa) on cellular damage caused by ultraviolet B (UVB)-induced oxidative stress in human dermal fibroblast cells. The results show that the protective effect of COS on UVB-stressed human fibroblasts was dependent on molecular weight. COS suppressed UVB irradiation-induced reactive oxygen species generation and DNA damage, accompanied by the downregulation of matrix metalloproteinase (MMP)-1 and MMP-13. In a comparative analysis, COS (3-5 kDa) exhibited the most potent protective effect on UVB-stressed fibroblasts. The presence of COS (3-5 kDa) attenuated UVB-induced collagenolytic MMP production and collagen degradation. The photoprotective activity of COS (3-5 kDa) was confirmed by transcriptional phosphorylation of mitogen-activated protein kinase-responsive signaling pathways.

N-Acetylglucosamine suppress collagenases activation in ultraviolet B-irradiated human dermal fibroblasts: Involvement of calcium ions and mitogen-activated protein kinases

BACKGROUND

N-Acetylglucosamine (GlcNAc) and its derivates have been utilized in dietary supplements and for therapeutic development due to their unique characteristics. GlcNAc is recognized primarily for its function as a precursor to hyaluronic acid, which plays a significant role in the structure and hydration of the extracellular matrix in skin, in both the epidermis and the dermis.

OBJECTIVE

We investigated the protective effects of GlcNAc on immortalized human skin fibroblasts (HS68) against UVB damage. We then explored the inhibitory effects of GlcNAc on UVB-induced collagenases and investigated the molecular mechanism underlying those effects.

METHODS

Those effects were assessed by semi-quantitative PCR, Western blotting and enzymatic activity assays.

RESULTS

GlcNAc increased the viability of, and inhibited ROS production in, HS68 cells exposed to UVB irradiation. Pre-treatment of HS68 cells with GlcNAc inhibited UVB-induced production of the collagenases MMP-1 and MMP-13. Western blot analysis further revealed that GlcNAc markedly suppressed the enhancement of collagen degradation in UVB-exposed HS68 cells. GlcNAc also suppressed UVB-induced activation of c-Jun, c-Fos and NF-κB and the phosphorylation of MAPKs and PI3K/Akt, upstream modulators of AP-1 and NF-κB. Moreover, GlcNAc decreased the UVB-induced influx of Ca(2+) into HS68 cells and the phosphorylation of Ca(2+)/calmodulin-dependent kinases (CaMKs).

CONCLUSION

The results indicate that GlcNAc inhibited UVB-induced collagenolytic MMP production by interfering with Ca(2+)-dependent Akt and MAPKs/AP-1 and NF-κB signaling. They may thus be potentially useful in the prevention and treatment of skin photoaging.

Topical retinoids in the management of photodamaged skin: from theory to evidence-based practical approach

Skin, being exposed directly to the environment, represents a unique model for demonstrating the synergistic effects of intrinsic and extrinsic factors on the ageing process. Ultraviolet radiation (UVR) is the major factor among exogenous stressors responsible for premature skin ageing. The problem of skin ageing has captured public attention and has an important social impact. Different therapeutic approaches have been developed to treat cutaneous ageing and to diminish or prevent the negative effects of UVR. Topical retinoids represent an important and powerful class of molecules in the dermatologist's hands for the treatment of photodamaged skin. Since their introduction more than 20 years ago, topical retinoids have shown beneficial efficacy and good safety profiles in the management of photodamaged skin, and as therapeutic anti-ageing agents. This review provides a brief retrospective of the development of topical retinoids in the treatment of photodamaged skin, elucidates their mechanism of action, delineates their use and addresses clinical, pharmaceutical and regulatory issues in connection with their intended use.

The flavonoids apigenin and luteolin suppress ultraviolet A-induced matrix metalloproteinase-1 expression via MAPKs and AP-1-dependent signaling in HaCaT cells

BACKGROUND

Ultraviolet (UV) irradiation causes major changes in skin connective tissues as a result of the degradation of collagen, a major structural component of the extracellular matrix. This process is likely mediated by matrix metalloproteinases (MMPs). Such changes in collagenous skin tissues have been suggested to be causes of cutaneous aging and skin cancer.

OBJECTIVE

We investigated the protective effects of apigenin and luteolin on immortalized human keratinocytes (HaCaT) against UVA damage. We then explored the inhibitory effects of apigenin and luteolin on UVA-induced MMP-1 and investigated the molecular mechanism underlying those effects.

METHODS

HaCaT cells were treated with apigenin and luteolin for the indicated times followed by irradiation with UVA. Those effects were assessed by semi-quantitative PCR, Western blotting and enzymic activity assays.

RESULTS

These two compounds, at concentrations of 1-5μM, increased the viability of, and inhibited ROS production in HaCaT cells exposed to UVA irradiation. Pre-treatment of HaCaT cells with apigenin and luteolin also inhibited UVA-induced production of the collagenases MMP-1. They also suppressed UVA-induced expression of c-Jun and c-Fos and the phosphorylation of three MAP kinases, upstream modulators of AP-1. Furthermore, the same two flavonoids decreased the UVA-induced influx of Ca(2+) into HaCaT cells and the phosphorylation of Ca(2+)/calmodulin-dependent kinases (CaMKs).

CONCLUSION

The results indicate that apigenin and luteolin inhibited UVA-induced collagenolytic MMP-1 production by interfering with Ca(2+)-dependent MAPKs and AP-1 signaling. They may thus be potentially useful in the prevention and treatment of skin photoaging.

Vibrational spectroscopic studies and ab initio calculations of Goniothalamin, a natural product

5,6-Dihydro-6-styryl-2-pyrone (Goniothalamin), is isolated from the leaves of Goniothalamus wightii and identified by spectral analysis and X-ray diffraction studies. FT-IR spectroscopy has also been used to characterize the vibrational bands. The vibrational wavenumbers and corresponding vibrational assignments are examined theoretically using the Gaussian03 set of quantum chemistry codes. Predicted IR and Raman intensities are reported.

How best to halt and/or revert UV-induced skin ageing: strategies, facts and fiction

Once considered mainly a cosmetic issue, photoageing research has long moved to the forefront of investigative dermatology. Besides obvious market pressures, increasing insight into the mechanistic overlap between UV-induced skin cancer and UV-induced skin ageing has contributed to this development. Also, as strategies that work to antagonize intrinsic skin ageing/senescence may also be exploited against photoageing (and vice versa!), it has become an important skin research challenge to dissect both the differences and the overlap mechanisms between these interwined, yet distinct phenomena. Finally, the current surge in putative 'antiageing' products, devices, and strategies - too many of which boldly promise to fight and/or repair the perils that come along with a lifetime spent in the sun in the absence of convincing evidence of efficacy - makes it particularly pertinent to critically review the available evidence to support often made antiageing claims. The current CONTROVERSIES feature, therefore, aimed to provide both guidance through, and critical voices in, the antiageing circus. Here, a panel of experts defines relevant key problems, points the uninaugurated to intriguing aspects of photoageing that one may not have considered before, highlights promising strategies for how best to halt and/or revert it, and spiritedly debates some controversially discussed approaches.

Retinoids in the treatment of skin aging: an overview of clinical efficacy and safety

Aging of skin is an intricate biological process consisting of two types. While intrinsic or chronological aging is an inevitable process, photoaging involves the premature aging of skin occurring due to cumulative exposure to ultraviolet radiation. Chronological and photoaging both have clinically differentiable manifestations. Various natural and synthetic retinoids have been explored for the treatment of aging and many of them have shown histological and clinical improvement, but most of the studies have been carried out in patients presenting with photoaged skin. Amongst the retinoids, tretinoin possibly is the most potent and certainly the most widely investigated retinoid for photoaging therapy. Although retinoids show promise in the treatment of skin aging, irritant reactions such as burning, scaling or dermatitis associated with retinoid therapy limit their acceptance by patients. This problem is more prominent with tretinoin and tazarotene whereas other retinoids mainly represented by retinaldehyde and retinol are considerably less irritating. In order to minimize these side effects, various novel drug delivery systems have been developed. In particular, nanoparticles have shown a good potential in improving the stability, tolerability and efficacy of retinoids like tretinoin and retinol. However, more elaborate clinical studies are required to confirm their advantage in the delivery of topical retinoids.

(-)Epigallocatechin gallate hampers collagen destruction and collagenase activation in ultraviolet-B-irradiated human dermal fibroblasts: involvement of mitogen-activated protein kinase

Ultraviolet (UV) irradiation leads to distinct changes in skin connective tissues by degradation of collagen, which is a major structural component in the extracellular matrix most likely mediated by matrix metalloproteinases (MMP), collagenases. These changes in collagenous skin tissues have been suggested to be causes of the skin wrinkling observed in premature aging of the skin. This study mimicked the action of environmental ultraviolet on skin and investigated whether (-)epigallocatechin gallate (EGCG), a bioactive catechin component of green tea, mechanistically inhibited activation of MMP-1, MMP-8, and MMP-13 and destruction of collagen in UV-B irradiated human dermal fibroblasts by modulating cellular signaling pathways. Cell viability was moderately decreased by > or = 30% in human dermal fibroblasts treated with 100 mJ/cm2 UV-B, accompanying a substantial generation of reactive oxygen species evidenced by DCF staining. Western blot analysis and immunocytochemical staining revealed that EGCG markedly suppressed collagen degradation enhanced in UV-B-exposed human dermal fibroblast. Pre-treatment of fibroblasts with EGCG also inhibited UV-B-induced production of collagenases, MMP-1, MMP-8 and MMP-13, in a dose-dependent manner. In addition, EGCG rapidly and substantially hampered UV-B irradiation-induced activation of ASK-1 and phosphorylation of MAPK, JNK, p38 MAPK, and ERK1/2, in dermal fibroblasts. These results demonstrate that EGCG has abilities to hamper UV-B-induced collagenolytic MMP production via interfering with the MAPK-responsive pathways. Therefore, EGCG may be a potential agent for the prevention and treatment of skin photoaging.

High MMP-1 mRNA expression is a risk factor for disease-free and overall survivals in patients with invasive breast carcinoma

BACKGROUND

Matrix metalloproteinase 1 (MMP-1) degrades extracellular matrix and thereby promotes tumor invasion and progression. In this study we examined the prognostic significance of tissue expression levels of MMP-1 mRNA in patients with invasive breast carcinoma.

MATERIALS AND METHODS

We assessed the prognostic value of MMP-1 mRNA expression in tumor tissue specimens from 85 breast carcinoma patients with a median follow-up time of 38 months (range, 2-48 months). MMP-1 mRNA levels were measured by real-time quantitative reverse transcriptase polymerase chain reaction (real time RT-PCR). The results were correlated with various clinicopathological parameters and clinical outcomes.

RESULTS

mRNA expression levels of MMP-1 were higher in tumor tissue specimens than in adjacent normal breast tissue specimens from 15 patients (P < 0.023). MMP-1 mRNA levels showed no significant relationship with either tumor size or axillary node status but correlated inversely with estrogen receptor levels (P < 0.0043). High MMP-1 mRNA expression as determined by real-time RT-PCR correlated significantly with a high frequency of recurrence and fatal outcome (P < 0.025 and P < 0.020). Multivariate analysis using the Cox regression model indicated that high MMP-1 mRNA expression was an independent unfavorable prognostic factor (risk ratio, 6.37; P < 0.019).

CONCLUSIONS

We have demonstrated for the first time the high mRNA expression of MMP-1 in patients whose carcinomas lack estrogen receptor expression. Our results suggest that MMP-1 is an important gene implicated in the progression of human breast cancer.

Regulation of type I procollagen and MMP-1 expression after single or repeated exposure to infrared radiation in human skin

Human skin is daily exposed to infrared (IR) radiation from natural sunlight. However, the effects of IR irradiation on collagen metabolism have not been investigated in human skin in vivo. Here, we examined whether single or repeated (three times a week for 4 weeks) exposure to IR irradiation changes the expressions of type I procollagen and interstitial collagenase (MMP-1). By using immunostaining, Western blotting, and semi-quantitative RT-PCR, we analyzed the protein and mRNA levels of type I procollagen and MMP-1 in young buttock skin. A single dose of IR to human skin increased the expression of type I procollagen within 24h, but did not change the expression of MMP-1. On the other hand, multiple IR doses reduced the expression of type I procollagen and increased the expression of MMP-1. We also found that TGF-betas may mediate type I procollagen synthesis in IR-irradiated human skin. Our results demonstrate that the regulations of the expressions of type I procollagen and MMP-1 differ in acute and chronically IR-irradiated skin. In particular, decreased collagen levels and increased MMP-1 levels in chronic IR-irradiated skin may be associated with connective tissue damage. Thus, we suggest that repeated exposure to IR irradiation might induce premature skin aging (photoaging) in human skin in vivo.