α-Ionone Protects Against UVB-Induced Photoaging in Human Dermal Fibroblasts

Fermented Fish Collagen Diminished Photoaging-Related Collagen Decrease by Attenuating AGE-RAGE Binding Activity

Ultraviolet (UV) irradiation causes skin wrinkles and decreases elasticity. UV also increases binding between advanced glycation end products (AGEs) and the receptor for AGEs (RAGE), resulting in increased inflammation and activation of NF-κB. We evaluated whether fermented fish collagen (FC) could decrease photoaging via decreasing AGE-RAGE binding activity, which was associated with decreased TNF-α and NF-κB levels in UV-irradiated keratinocytes and animal skin. In the UV-irradiated keratinocytes, AGE-RAGE binding activity and TNF-α secretion levels were increased, and FC decreased these. Additionally, AGE-RAGE binding activity and TNF-α secretion levels were attenuated by soluble RAGE (RAGE inhibitor) in the UV-irradiated keratinocytes. FC decreased AGE-RAGE binding activity, TNF-α levels, and translocation of NF-κB in the UV-irradiated skin. Furthermore, FC decreased the expression of matrix metalloproteinases 1/3/9, which degrades collagen fibers, and Smad7, which inhibits Smad2/3, in UV-irradiated skin. FC increased Smad2/3 and collagen fiber accumulation. FC also increases skin moisture and elasticity. In conclusion, FC could attenuate skin photoaging via decreasing AGE-RAGE binding activity and its downstream signals such as TNF-α and NF-κB.

Discovery of matrix metalloproteinase inhibitors as anti-skin photoaging agents

Photodamage is the result of prolonged exposure of the skin to sunlight. This exposure causes an overexpression of matrix metalloproteinases (MMPs), leading to the abnormal degradation of collagen in the skin tissue and resulting in skin aging and damage. This review presents a detailed overview of MMPs as a potential target for addressing skin aging. Specifically, we elucidated the precise mechanisms by which MMP inhibitors exert their anti-photoaging effects. Furthermore, we comprehensively analyzed the current research progress on MMP inhibitors that demonstrate significant inhibitory activity against MMPs and anti-skin photoaging effects. The review also provides insights into the structure-activity relationships of these inhibitors. Our objective in conducting this review is to provide valuable practical information to researchers engaged in investigations on anti-skin photoaging.

Dietary supplementation with α-ionone alleviates chronic UVB exposure-induced skin photoaging in mice

Photoaging is widely regarded as the most significant contributor to skin aging damage. It is triggered by prolonged exposure to ultraviolet (UV) light and typically manifests as dryness and the formation of wrinkles. Nutritional intervention is a viable strategy for preventing and treating skin photoaging. In previous studies, we demonstrated that α-ionone had ameliorating effects on photoaging in both epidermal keratinocytes and dermal fibroblasts. Here, we investigated the potential anti-photoaging effects of dietary α-ionone using a UVB-irradiated male C57BL/6N mouse model. Our findings provided compelling evidence that dietary α-ionone alleviates wrinkle formation, skin dryness, and epidermal thickening in chronic UVB-exposed mice. α-Ionone accumulated in mouse skin after 14 weeks of dietary intake of α-ionone. α-Ionone increased collagen density and boosted the expression of collagen genes, while attenuating the UVB-induced increase of matrix metalloproteinase genes in the skin tissues. Furthermore, α-ionone suppressed the expression of senescence-associated secretory phenotypes and reduced the expression of the senescence marker p21 and DNA damage marker p53 in the skin of UVB-irradiated mice. Transcriptome sequencing results showed that α-ionone modifies gene expression profiles of skin. Multiple pathway enrichment analyses on both the differential genes and the entire genes revealed that α-ionone significantly affects multiple physiological processes and signaling pathways associated with skin health and diseases, of which the p53 signaling pathway may be the key signaling pathway. Taken together, our findings reveal that dietary α-ionone intervention holds promise in reducing the risks of skin photoaging, offering a potential strategy to address skin aging concerns.

Approaches in line with human physiology to prevent skin aging

Skin aging is a complex process that is influenced by intrinsic and extrinsic factors that impact the skin's protective functions and overall health. As the body's outermost layer, the skin plays a critical role in defending it against external threats, regulating body temperature, providing tactile sensation, and synthesizing vitamin D for bone health, immune function, and body homeostasis. However, as individuals age, the skin undergoes structural and functional changes, leading to impairments in these essential functions. In contemporary society, there is an increasing recognition of skin health as a significant indicator of overall wellbeing, resulting in a growing demand for anti-aging products and treatments. However, these products often have limitations in terms of safety, effective skin penetration, and potential systemic complications. To address these concerns, researchers are now focusing on approaches that are safer and better aligned with physiology of the skin. These approaches include adopting a proper diet and maintaining healthy lifestyle habits, the development of topical treatments that synchronize with the skin's circadian rhythm, utilizing endogenous antioxidant molecules, such as melatonin and natural products like polyphenols. Moreover, exploring alternative compounds for sun protection, such as natural ultraviolet (UV)-absorbing compounds, can offer safer options for shielding the skin from harmful radiation. Researchers are currently exploring the potential of adipose-derived stem cells, cell-free blood cell secretome (BCS) and other endogenous compounds for maintaining skin health. These approaches are more secure and more effective alternatives which are in line with human physiology to tackle skin aging. By emphasizing these innovative strategies, it is possible to develop effective treatments that not only slow down the skin aging process but also align better with the natural physiology of the skin. This review will focus on recent research in this field, highlighting the potential of these treatments as being safer and more in line with the skin's physiology in order to combat the signs of aging.

Effects of probiotics supplementation on skin photoaging and skin barrier function: A systematic review and meta-analysis

BACKGROUND

Ultraviolet (UV) irradiation is one of the major causes of skin aging. To date, there remains limited evidence on using oral probiotics for skin anti-photoaging.

OBJECTIVES

This systematic review and meta-analysis aims to assess the effects of probiotics on skin photoaging.

METHODS

We searched the PubMed and Embase databases for studies published until August 31, 2021, and included randomized controlled trials, murine randomized controlled experiments, and in vitro studies. Skin barrier function was compared between UV irradiated probiotics and controls.

RESULTS

After given oral probiotics supplements, a significant reduction was shown in all types of measured MMPs in both murine and in vitro studies. Oral probiotics supplementation significantly reversed UV-induced increase of epidermal thickness (standardized mean differences [SMD] = -1.76; 95% confidence interval [CI] = -3.04 to -0.49; p = .007; I²  = 81%), UV-induced increase trans-epidermal water loss (SMD = -1.72; 95% CI = -2.76 to -0.67; p = .001; I²  = 57%), and UV-induced skin dehydration (SMD = 1.85; 95% CI = 1.16 to 2.55; p < .00001; I²  = 4%).

CONCLUSIONS

Probiotics are effective against skin photoaging in terms of MMP pathways and reversing skin barrier function from murine randomized data. Further randomized controlled trials on humans are required to warrant these results.

Molecular basis of skin photoaging and therapeutic interventions by plant-derived natural product ingredients: A comprehensive review

Skin areas exposed to ultraviolet radiation (UV) from sunlight are more prone to photoaging than unexposed areas evidenced by several signs which include skin dryness, irregular pigmentation, lentigines, hyperpigmentation, wrinkling, and decreased elasticity. Plant-based natural product ingredients with therapeutic potential against skin photoaging are gaining more attention. This article aims the reviewing the research work done in exploring the cellular and molecular mechanisms involved in UV-induced skin photoaging, followed by summarizing the mechanistic insights involved in its therapeutics by natural product-based ingredients. In the mechanistic section of the convoluted procedure of photoaging, we described the effect of UV radiation (UVR) on different cellular macromolecules (direct damage) and subsequently, the deleterious consequences of UVR-generated reactive oxygen species (indirect damage) and signaling pathways activated or inhibited by UV induced ROS generation in various cellular pathologies of skin photoaging like inflammation, extracellular matrix degradation, apoptosis, mitochondrial dysfunction, and immune suppression. We also discussed the effect of UV radiation on the adipose tissue, and transient receptor potential cation channel V of photoaging skin. In the past few decades, mechanistic studies performed in this area have deciphered various therapeutic targets, opening avenues for different available therapeutic options against this pathological condition. So the remaining portion of the review deals with various natural product-based therapeutic agents available against skin photodamage.

α-Ionone protects against UVB-induced photoaging in epidermal keratinocytes

Objective

To evaluate whether α-ionone, an aromatic compound mainly found in raspberries, carrots, roasted almonds, fruits, and herbs, inhibits UVB-mediated photoaging and barrier dysfunction in a human epidermal keratinocyte cell line (HaCaT cells).

Methods

The anti-photoaging effect of α-ionone was evaluated by detecting the expression of barrier-related genes and matrix metalloproteinases (MMPs) in HaCaT cells. The levels of reactive oxygen species, oxidation product, antioxidant enzyme, and inflammatory factors were further analysed to underline the protective effect of α-ionone on epidermal photoaging.

Results

It was found that α-ionone attenuated UVB-induced barrier dysfunction by reversing keratin 1 and filaggrin in HaCaT cells. α-Ionone also reduced the protein amount of MMP-1 and mRNA expression of MMP-1 and MMP-3 in UVB-irradiated HaCaT cells, implying protective effects on extracellular matrix. Furthermore, HaCaT cells exposed to α-ionone showed significant decreases in interleukin (IL)-1β, IL-6, IL-8, and tumor necrosis factor-α as compared to UVB-irradiated HaCaT cells. α-Ionone treatment significantly inhibited the UVB-induced intracellular reactive oxygen species increase and malondialdehyde accumulation. Therefore, the beneficial effects of α-ionone on inhibiting MMPs secretion and barrier damage may be related to attenuated inflammation and oxidative stress.

Conclusion

Our results highlight the protective effects of α-ionone on epidermal photoaging and promote its clinic application as a potential natural anti-photodamage agent in future.

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.

Ectopic odorant receptors responding to flavor compounds in skin health and disease: Current insights and future perspectives

Skin, the largest organ of human body, acts as a barrier to protect body from the external environment and is exposed to a myriad of flavor compounds, especially food- and plant essential oil-derived odorant compounds. Skin cells are known to express various chemosensory receptors, such as transient potential receptors, adenosine triphosphate receptors, taste receptors, and odorant receptors (ORs). We aim to provide a review of this rapidly developing field and discuss latest discoveries related to the skin ORs activated by flavor compounds, their impacts on skin health and disease, odorant ligands interacting with ORs exerting specific biological effects, and the mechanisms involved. ORs are recently found to be expressed in skin tissue and cells, such as keratinocytes, melanocytes, and fibroblasts. To date, several ectopic skin ORs responding to flavor compounds, are involved in different skin biological processes, such as wound healing, hair growth, melanin regulation, pressure stress, skin barrier function, atopic dermatitis, and psoriasis. The recognition of physiological role of skin ORs, combined with the fact that ORs belong to a highly druggable protein family (G protein-coupled receptors), underscores the potential of skin ORs responding to flavor compounds as a novel regulating strategy for skin health and disease.

Protective Effect of Fat-Tissue-Derived Products against Ultraviolet Irradiation-Induced Photoaging in Mouse Skin

BACKGROUND

Exposure to ultraviolet radiation causes erythema, inflammation, and photoaging. Mechanical micronization of adipose tissue can concentrate functional cells and has great potential as an alternative for regenerative medicine. Stromal vascular fraction gel is produced by means of a series of mechanical processes of lipoaspirates and can be injected intradermally. This study aimed to assess the therapeutic effect of stromal vascular fraction gel on photoaging skin.

METHODS

A photoaging model was established in nude mice. Photoaging mice received treatments of stromal vascular fraction gel, fat, tretinoin, or phosphate-buffered saline. Photoaging skin was characterized by histologic and immunohistochemical analyses. Expression of collagen synthesis-related or photoaging-related genes was assessed.

RESULTS

Stromal vascular fraction gel, fat, and tretinoin reversed photoaging, whereas stromal vascular fraction gel demonstrated the greatest therapeutic effect. Treatment with stromal vascular fraction gel restored intradermal fat tissue content and increased dermal collagen density. Injection of stromal vascular fraction gel had the strongest effect on stimulating fibroblasts and increasing the expression of transforming growth factor β1 (TGF-β1), propeptide of type-I procollagen, and Smad 2, decreasing the expression of Smad 3, compared with fat and tretinoin. Expression of photoaging-related genes was significantly reduced, whereas expression of fibulin-5 was significantly increased after stromal vascular fraction gel treatment.

CONCLUSIONS

Stromal vascular fraction gel demonstrated remarkable therapeutic effects in reversing photoaging skin. Stromal vascular fraction gel can be injected intradermally and survive within dermal layer after grafting. This product increased TGF-β1expression and activated fibroblasts to produce propeptide of type I procollagen, thus increasing the amount of collagen I, leading to thickening of the dermis of photoaging skin.

Boosting the Photoaged Skin: The Potential Role of Dietary Components

Skin photoaging is mainly induced by ultraviolet (UV) irradiation and its manifestations include dry skin, coarse wrinkle, irregular pigmentation, and loss of skin elasticity. Dietary supplementation of nutraceuticals with therapeutic and preventive effects against skin photoaging has recently received increasing attention. This article aims to review the research progress in the cellular and molecular mechanisms of UV-induced skin photoaging. Subsequently, the beneficial effects of dietary components on skin photoaging are discussed. The photoaging process and the underlying mechanisms are complex. Matrix metalloproteinases, transforming growth factors, skin adipose tissue, inflammation, oxidative stress, nuclear and mitochondrial DNA, telomeres, microRNA, advanced glycation end products, the hypothalamic-pituitary-adrenal axis, and transient receptor potential cation channel V are key regulators that drive the photoaging-associated changes in skin. Meanwhile, mounting evidence from animal models and clinical trials suggests that various food-derived components attenuate the development and symptoms of skin photoaging. The major mechanisms of these dietary components to alleviate skin photoaging include the maintenance of skin moisture and extracellular matrix content, regulation of specific signaling pathways involved in the synthesis and degradation of the extracellular matrix, and antioxidant capacity. Taken together, the ingestion of food-derived functional components could be an attractive strategy to prevent skin photoaging damage.

HS-SPME and GC/MS volatile component analysis of Yinghong No. 9 dark tea during the pile fermentation process

Each type of tea has a unique volatile profile due to its variety, processing technologies and origin. Using HS-SPME and GC/MS, we analyzed the changes of volatile components in cultivar Yinghong No. 9 during pile-fermentation every 10 days. A total of 94 compounds showed significant differences during a total of 60 days mainly including alkanes, ketones, esters, terpenes, aromatics and heterocyclic compounds. Interestingly, 13 metabolites were progressively reduced during the first 20 days and remained unchanged in subsequent procedures, while 17 metabolites remained unchanged in the early stage and progressively increased during the last 20 days of pile fermentation, indicating that they are characteristic volatile compounds of raw material sun-dried green tea and dark tea, respectively. β-ionone, phenylethyl alcohol, and a-ionone could be the top three contributed aroma compounds in the final dark tea. Our study provides a theoretical basis for process and quality improvement of Yinghong No. 9.

Albizia lebbeck and Albizia zygia volatile oils exhibit anti-nociceptive and anti-inflammatory properties in pain models

ETHNOPHARMACOLOGICAL RELEVANCE

Albizia lebbeck and Albizia zygia are used in Nigeria, South Africa and other countries for the treatment of flu, fever, pain, epilepsy, and inflammation.

AIM OF THE STUDY

Application of plant essence for treating ailments is common among local communities. This research was designed to characterize the volatile compounds and evaluate the toxicity, anti-inflammatory and anti-nociceptive properties of this plant species.

MATERIALS AND METHODS

The volatile oils were analysed comprehensively utilizing gas chromatography-flame ionization detector (GC-FID) and gas chromatography coupled with mass spectrometry (GC/MS) using the HP-5 column. The toxicity was evaluated using the toxicity assay. The anti-nociceptive and anti-inflammatory assays were analysed by a hot plate, Formalin, and carrageenan-induced edema assays, respectively.

RESULTS

The essential oils were obtained in a yield of 0.1% (v/w) calculated on a dry weight basis for both oils. The main compounds of A. lebbeck were 2-pentylfuran (16.4%), (E)-geranyl acetone (15.46%), (E)-α-ionone (15.45%) and 3-Octanone (11.61%), while the oil of A. zygia is mainly hexahydrofarnesyl acetone (33.14%), (E)-methyl isoeugenol (11.7%) and 2-methyl tetradecane (6.64%). The volatile oils are non-toxic to about 5000 mg/kg dose. Albizia zygia significantly (P < 0.001) suppressed the nociceptive afferent fibres in a non-dose dependent manner in comparison to A. lebbeck in the hot plate model. Both oils inhibited nociceptive mediators at both phases of the formalin-induced assay, with a maximum inhibition (100%) at the inflammatory stage. The volatile oils inhibited the Carrageenan-induced inflammation at all phases ranging from P < 0.05 to P < 0.001. The probable pro-inflammatory inhibitory mechanism might be the suppression of some pain biomarkers such as histamine, serotonin, bradykinin, and the Interleukins (ILs) induced by the edema. Volatile constituents such as ionones, eugenol derivatives and other compounds cause the anti-nociceptive and anti-inflammatory activities reported.

CONCLUSION

This is the first report of the volatile oils and bioassays of Albizia zygia, while the study also confirms previous studies of A. lebbeck. Generally, the findings further prove the use of the plants as pain ameliorating agents.

Human mesenchymal stem cells respond differentially to platelet preparations and synthesize hyaluronic acid in nucleus pulposus extracellular matrix

BACKGROUND CONTEXT

In recent years, autologous platelet-rich plasma (PRP) and bone marrow aspirate concentrate (BMAC) have been used as treatments for disc-related pain. A better understanding of the effects of leukocyte-rich (LR) versus leukocyte poor (LP-) PRP on bone marrow derived human mesenchymal stem/progenitor cells (hMSCs) is likely to improve future research studies, clinical practice and care for patients with chronic discogenic back pain.

PURPOSE

The primary aim of this study is to determine the effects of LR-PRP and LP-PRP on the proliferation and migration of hMSCs in pig nucleus pulposus (NP) extracellular matrix (ECM). The secondary aim is to characterize hMSC-dependent expression of the matrix remodeling enzymes metalloproteinases MMP-2, MMP-3, MMP-9 and tissue inhibitor of metalloproteinases TIMP-2, and to determine whether transplanted hMSCs can synthesize hyaluronic acid (HA).

STUDY DESIGN

Controlled laboratory study.

METHODS

Bone marrow-derived culture expanded hMSCs were seeded onto pig NP and cultured with LR-PRP, LP-PRP or serum/platelet releasate (PR). The same conditions without hMSCs were used as controls. hMSC proliferation, migration and dispersion was assessed via fluorescent microscopy, while HA synthesis, MMP-2, MMP-3, MMP-9, and TIMP-2 protein levels were assessed via enzyme linked immunosorbent assay. All funding was provided by a 501c(3) research foundation and does not have any commercial or sponsorship interests.

RESULTS

LP-PRP and PR cultures resulted in higher hMSC proliferation, migration, dispersion, and MMP-2 expression. LP-PRP cultures resulted in the highest HA production. LR-PRP cultures resulted in lower hMSC proliferation, negligible migration and dispersion, increased MMP-9 expression and lower HA production.

CONCLUSIONS

Human bone marrow-derived hMSCs seeded onto pig NP ECM are capable of synthesizing HA, indicating a transition towards a NP cell phenotype. This process was most enhanced by LP-PRP and marked by increased hMSC proliferation, MMP-2 production, HA synthesis and reduced MMP-9 levels.

CLINICAL SIGNIFICANCE

LP-PRP and PR, with or without hMSCs, may provide better outcomes than LR-PRP in lab investigations and clinical trials for discogenic pain. Bone marrow-derived hMSCs may hold promise as a treatment for disc degeneration.

Erratum: Tong, T., et al. α-Ionone Protects Against UVB-Induced Photoaging in Human Dermal Fibroblasts. Molecules 2019, 24, 1804

The authors wish to make the following change to their paper [...].

Decanal Protects against UVB-Induced Photoaging in Human Dermal Fibroblasts via the cAMP Pathway

Solar ultraviolet (UV) radiation is the primary factor of cutaneous aging, resulting in coarse wrinkles and dryness. In this study, we aimed to test whether decanal, an aromatic compound found mainly in citrus fruits, inhibits UVB-mediated photoaging in human dermal fibroblasts and to explore whether its anti-photoaging effect occurs via cyclic adenosine monophosphate (cAMP) signaling. We found that decanal promotes collagen production dose-dependently. Meanwhile, it also increased the intracellular cAMP levels and decreased the number of molecules involved in the mitogen-activated protein kinase (MAPK)/activator protein 1 (AP-1) pathway, downregulating the collagen genes and upregulating the matrix metalloproteinase (MMP) genes in UVB-exposed dermal fibroblasts. Furthermore, it enhanced hyaluronic acid levels and hyaluronic acid synthase mRNA expression. Notably, the beneficial effects of decanal were lost in the presence of a cAMP inhibitor. Our results revealed the potential of decanal for preventing photoaging and suggested that its effects are cAMP-mediated in human dermal fibroblasts.

Antiwrinkle and Antimelanogenesis Effects of Tyndallized Lactobacillus acidophilus KCCM12625P

UVB irradiation can induce generation of reactive oxygen species (ROS) that cause skin aging or pigmentation. Lactobacillus acidophilus is a well-known probiotic strain that regulates skin health through antimicrobial peptides and organic products produced by metabolism and through immune responses. In this study, we investigated the antioxidative, antiwrinkle, and antimelanogenesis effects of tyndallized Lactobacillus acidophilus KCCM12625P (AL). To analyze the effects of AL on UV irradiation-induced skin wrinkle formation in vitro, human keratinocytes and human dermal fibroblasts were exposed to UVB. Subsequent treatment with AL induced antiwrinkle effects by regulating wrinkle-related genes such as matrix metalloproteinases (MMPs), SIRT-1, and type 1 procollagen (COL1AL). In addition, Western blotting assays confirmed that regulation of MMPs by AL in keratinocytes was due to regulation of the AP-1 signaling pathway. Furthermore, we confirmed the ability of AL to regulate melanogenesis in B16F10 murine melanoma cells treated with α-melanocyte-stimulating hormone (α-MSH). In particular, AL reduced the mRNA expression of melanogenesis-related genes such as tyrosinase, TYRP-1, and TYRP-2. Finally, we used Western blotting assays to confirm that the antimelanogenesis role of AL was due to its regulation of the cyclic adenosine monophosphate (cAMP) signaling pathway. Collectively, these results indicate that AL has an antiwrinkle activity in damaged skin and can inhibit melanogenesis. Thus, AL should be considered an important substance for potential use in anti-aging drugs or cosmetics.