Topical retinol attenuates stress‐induced ageing signs in human skin ex vivo, through EGFR activation via EGF , but not ERK and AP ‐1 activation

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.

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.

Ferulic acid in synergy with retinol alleviates oxidative injury of HaCaT cells during UVB-induced photoaging

Application of retinol (Vitamin A, VA) in skincare is limited for instability, poor water solubility, and skin intolerance that combats skin aging. We employed computer-aided virtual screening and cell experiments with transcriptomics, thereby unveiling the comprehensive gene expression and regulation pathway of photoaging HaCaT cell treated with ferulic acid (FA) in synergizing with VA. Through network pharmacology analysis, the combined use of VA and FA exhibited highly correlated cross-targets with skin aging acting on EGFR, PTPN1, ESR2, GSK3B, BACE1, PYGL, PTGS2 and APP. The indicators of oxidative stress, such as SOD, GSH, MDA, CAT and ROS in HaCaT cells after co-administration, were significantly improved from those in photoaging group (p<0.0001). 155 differential expressed genes (DEGs) were specific between groups, while reducing the expression of PTGS2 was identified as an important regulatory factor in photoaging HaCaT cells by VA and FA. Those DEGs of co-administration group focused on oxidative-reduction enzyme activity, skin growth, keratinization, and steroid biosynthesis. Apparently, the co-administration of VA and FA effectively mitigated the process of UVB-induced photoaging by reducing oxidative stress injury, inflammation responses, and regulating cell growth. This synergistic approach significantly slowed down the photoaging progression and improved the applied performance of VA in HaCaT cells.

Sustained Release Microneedles: Materials and Applications in Facial Rejuvenation

Wrinkled and loose skin resulting from collagen degradation along with fibers decreasing reflects the youth diminishing. Microneedles (MNs) have opened up new avenues for the development of painless and noninvasive transdermal drug delivery systems for facial rejuvenation. Encapsulated drugs or molecules are transmitted to targeted tissues via percutaneous microchannels, which eliminate potential gastric stimulation or first-pass metabolic effects, as well as boost patient compliance. Although MNs are considered effective and feasible therapeutic alternatives to metals, silicon, and polymers, traditional procedures with reduction processes continue to encounter methodological limitations. In recent years, promising additive manufacturing processes such as three-dimensional printing and two-photon polymerization manufacturing have been developed with the aim of overcoming the limitations by traditional processes to facilitate an efficient and economic production mode. This review summarizes the design, material selection, and manufacturing method for recently advanced MN systems. Furthermore, we also highlight specific polymeric or natural microneedle products, like hyaluronan, plant derivates, and vitamins, for esthetic applications in this review. Impact Statement In this review, the materials and manufactural routes of microneedles (MNs) are detailed. Moreover, similar to the diagnostic or therapeutic MNs, the feature of dispensation with training and ready-to-use is perfect for beautification and anti-aging, which necessitate repeated and long-term usage. Furthermore, the specific polymeric or natural products for esthetic applications of MNs are highlighted in this review.

Uncoupling melanogenesis from proliferation in epidermal melanocytes responding to stimulation with psoriasis-related proinflammatory cytokines

BACKGROUND

Few studies have addressed the impact of the psoriasis-related proinflammatory cytokines on the proliferation and melanogenesis of melanocytes (MCs) in lesional psoriatic skin.

OBJECTIVE

We investigated the effects of TNFα, IL17A, and IL8 on the proliferation and melanin synthesis of MCs.

METHODS

Skin specimens were biopsied from patients with psoriasis vulgaris at the active stage, or from the tail skin of Dct-LacZ mice with imiquimod (IMQ)-induced psoriasiform dermatitis. Cultured keratinocytes (KCs), MCs, and human skin explants were used in this study. The numbers of MCs were measured via β-galactosidase staining, EdU incorporation and HMB45 immunohistochemical staining. The expression of human β-defensin 3 (hBD3) in KCs was silenced by siRNA, the conditioned medium (CM) from siRNA-transfected KCs was used to treat MCs, then followed by αMSH stimulation. The melanogenesis-related genes were examined by using qRT-PCR and western blotting.

RESULTS

The increased number of MCs and decreased melanin content were highly relevant to the enhanced expression of IL8 and BD3 both in human psoriatic skin and in IMQ-treated mouse tail skin. IL8 expression in KCs and CXCR2 expression in MCs was significantly increased by IL17A and TNFα, the αMSH-induced upregulations of microphthalmia-associated transcription factor (MITF) and tyrosinase in MCs were abrogated by the CM from hBD3-unsilenced KCs, but not from hBD3-silenced KCs.

CONCLUSION

Our results suggest the roles of IL8-CXCR2 activation in promoting MC proliferation and of BD3 upregulation in reducing melanogenesis. These findings have been implicated in the underlying mechanism that active psoriasis prefers hypopigmentation despite chronic inflammation.

Exploring the mechanisms of action of Cordyceps sinensis for the treatment of depression using network pharmacology and molecular docking

Background

Depression is the most common type of psychological disorder, with continuous, prolonged, and persistent bad moods as the main clinical feature. Cordyceps sinensis is a complex consisting of the ascospores and bodies of insect larvae from the Hepialidae family that have been parasitized by Cordyceps sinensis militaris. Previous studies have reported that this herb has antidepressant activity. The present study used network pharmacology and molecular docking techniques to investigate the potential antidepressant mechanisms of Cordyceps sinensis.

Methods

The active ingredients of Cordycepssinensis were identified using the Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform (TCMSP) and the potential targets were predicted using the PharmMapper platform. The GeneCards database was then used to obtain sub-targets for depression. Common targets were screened and enrichment analyses were performed using the Metascape platform. Finally, the relationship between the active ingredients and the core targets were verified by molecular docking.

Results

Through network pharmacological analysis, 7 active ingredients in Cordyceps sinensis and 41 common targets of drugs and diseases were identified. The active ingredients of Cordyceps sinensis may exert antidepressant effects by acting on important targets such as catalase (CAT), CREB binding protein (CREBBP), epidermal growth factor (EGF), and E1A binding protein P300 (EP300), and by modulating the signaling pathways in which these targets are involved. Subsequently, the core targets were docked to the active ingredients and good binding was observed.

Conclusions

The active ingredients of Cordycepssinensis may exert antidepressant effects by regulating the CREB binding protein and anti-oxidative stress effects. The foxo signaling pathway (hsa04068), hypoxia-inducible factor 1 (HIF-1) signaling pathway (hsa04066), and Huntington’s disease (hsa05016) may be involved in the underlying mechanisms of Cordycepssinensis. The joint application of network pharmacology and molecular docking provides a new approach to study the mechanisms of action of traditional Chinese medicine. Cordyceps sinensis may play an important role in the future treatment of patients with depression.

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.

An ex vivo model of human skin photoaging induced by UVA radiation compatible with summer exposure in Brazil

Skin is the largest body organ and can be affected by several factors, such as ultraviolet (UV) radiation. UV radiation is subdivided in UVA, UVB and UVC according to the radiation wavelength. UVC radiation does not cross the ozone layer; UVB cause DNA damage and is closely related to carcinogenesis; UVA radiation penetrates deeply into the skin, reaching epidermis and dermis and is considered the main promoter of skin aging, known as photoaging. In order to understand photoaging mechanisms and propose efficient therapies, several photoaging study models have been developed, each with benefits and limitations, but most of them use very high doses of UVA radiation, which is not compatible with our daily sun exposure. The objective of this work was to develop a human ex vivo photoaging model induced by UVA exposure compatible to a summer in Brazil. For this, human skin fragments were obtained from healthy donors who underwent otoplasty surgery and skin explants were prepared and placed in plates, with the epidermis facing upwards. Skin explants were exposed to UVA at 16 J/cm² carried out by protocols of 2 or 4 exposures. Results showed an increase of oxidative damage, inflammatory cells, collagenolytic and elastolytic MMPs expression as well as a decrease of elastin expression, suggesting that the experimental model based on skin explants is able to evaluate UVA-induced aging in human skin.

Menopause, Ultraviolet Exposure, and Low Water Intake Potentially Interact with the Genetic Variants Related to Collagen Metabolism Involved in Skin Wrinkle Risk in Middle-Aged Women

Genetic and environmental factors influence wrinkle development. We evaluated the polygenetic risk score (PRS) by pooling the selected single nucleotide polymorphisms (SNPs) from a genome-wide association study (GWAS) for wrinkles and the interaction of PRS with lifestyle factors in middle-aged women. Under the supervision of a dermatologist, the skin status of 128 women aged over 40 years old was evaluated with Mark-Vu, a skin diagnosis system. PRS was generated from the selected SNPs for wrinkle risk from the genome-wide association study. Lifestyle interactions with PRS were also evaluated for wrinkle risk. Participants in the wrinkled group were more likely to be post-menopausal, eat less fruit, take fewer vitamin supplements, exercise less, and be more tired after awakening in the morning than those in the less-wrinkled group. The PRS included EGFR_rs1861003, MMP16_rs6469206, and COL17A1_rs805698. Subjects with high PRS had a wrinkle risk 15.39-fold higher than those with low PRS after adjusting for covariates, and they had a 10.64-fold higher risk of a large skin pore size. Menopause, UV exposure, and water intake interacted with PRS for wrinkle risk: the participants with high PRS had a much higher incidence of wrinkle risk than those with low PRS, only among post-menopausal women and those with UV exposure. Only with low water intake did the participants with medium PRS have increased wrinkle risk. In conclusion, women aged >40 years with high PRS-related collagen metabolism may possibly avoid wrinkle risk by avoiding UV exposure by applying sunscreen, maintaining sufficient water intake, and managing estrogen deficiency.

[Functional integrity of aging skin, from cutaneous biology to anti-aging strategies]

The skin is a sentinel organ making easily visible the passing of time. Chronological and environmental aging weakens skin structure and functions. The skin barrier, the elastic and mechanical properties of the cutaneous tissue as well as its vascular reactivity are impacted by aging. The barrier dysfunction in aged skin is caused by defects in epidermal keratinocytes renewal and differentiation notably linked to abnormal expression of microRNAs regulating cell death and autophagy. An abnormal balance between synthesis and degradation of matrix proteins modifies the mechanical properties of the dermis in aged skin. Finally, a reduction of the vascular reactivity linked to endothelial dysfunctions is observed in elderly people. These biological processes can be targeted by therapeutic approaches either topical or systemic, especially using anti-oxydants or senolytics. These anti-aging strategies might contribute to restore, at least in part, the functional integrity of aged skin.

A Rose Extract Protects the Skin against Stress Mediators: A Potential Role of Olfactory Receptors

Olfactory receptors (ORs) are expressed and active in various human tissues, including the skin. Although the sense of smell plays an important physiological role in the regulation of mood and stress, a link between olfactive compounds, ORs, and skin stress has yet to be established. This study aims to investigate the role of newly identified skin ORs and agonists in the modulation of skin stress. Screening for odorant molecules was done with cAMP functional assay to identify OR agonists. RT-qPCR and immunofluorescence microscopy were conducted to identify and quantify ORs in epidermal keratinocytes (NHEKs) and human skin explants, as well as to evaluate specific markers (G6PDH, loricrin, and γH2AX) of stress-induced skin alterations. A randomized double-blinded, split-face clinical study was performed on a panel of stressed women to measure the benefits of OR agonist treatment for skin. Three new ORs (OR10A6, OR2AG2, and OR11H4) were identified in skin. A specific Rose extract and its major constituent (phenylethyl alcohol) were found to activate these ORs. The extract composition was revealed by both GC/FID and GC/MS analyses simultaneously and showed the presence of 34 volatiles molecules. Moreover, epinephrine induces a skin stress response characterized by increased expression of G6PD, loricrin, and γH2AX biomarkers, and a decrease of OR expression. These effects were prevented in the presence of rose extract and its benefits were confirmed clinically by a decrease in the appearance of under-eye dark circles. Altogether, our findings suggest that ORs may represent a new, promising way to treat stress-associated skin disorders.