Vitamin C-squalene bioconjugate promotes epidermal thickening and collagen production in human skin

Ex Vivo Patient-Derived Explant Model for Neurofibromatosis Type 1-Related Cutaneous Neurofibromas

Cutaneous neurofibromas (CNFs) are benign tumors that occur in the dermis of individuals with the inherited tumor predisposition disorder, neurofibromatosis type 1. CNFs cause disfigurement, pain, burning, and itching, resulting in substantially reduced QOL in patients with neurofibromatosis type 1. CNFs are benign tumors that exhibit cellular and molecular heterogeneity, making it difficult to develop tractable in vitro or in vivo models. As a result, CNF research and drug discovery efforts have been limited. To address this need, we developed a reproducible patient-derived explant (PDE) ex vivo culture model using CNF tumors from patients with neurofibromatosis type 1. CNF PDEs remain viable in culture for over 9 days and recapitulate the cellular composition and molecular signaling of CNFs. Using CNF PDEs as a model system, we found that proliferation was associated with increased T-cell infiltration. Furthermore, we identified a pattern of reciprocal inflammatory signaling in CNF PDEs in which tumors rely on prostaglandin or leukotriene-mediated signaling pathways. As proof of principle, we show that ex vivo glucocorticoid treatment reduced the expression of proinflammatory genes, confirming that CNF PDEs are a useful model for both mechanistic studies and preclinical drug testing.

Intra-articular injection of ascorbic acid enhances microfracture-mediated cartilage repair

Previous studies have confirmed that ascorbic acid (AA) can promote cartilage repair and improve cartilage differentiation in bone marrow mesenchymal stem cells. However, the use of microfracture (MFX) combined with AA to repair cartilage damage has not been studied. This study established a rabbit animal model and treated cartilage injury with different concentrations of AA combined with MFX. Macroscopic observations, histological analysis, immunohistochemical analysis and reverse transcription quantitative polymerase chain reaction analysis of TGF-β, AKT/Nrf2, and VEGF mRNA expression were performed. The results showed that intra-articular injection of AA had a positive effect on cartilage repair mediated by microfractures. Moreover, 10 mg/ml AA was the most effective at promoting cartilage repair mediated by microfractures. Intra-articular injection of AA promoted the synthesis of type II collagen and the formation of glycosaminoglycans by downregulating the mRNA expression of TGF-β and VEGF. In summary, this study confirmed that AA could promote cartilage repair after MFX surgery.

Engineering Saccharomyces cerevisiae for synthesis of β-myrcene and (E)-β-ocimene

Monoterpenes are among the important natural plant terpenes. Monoterpenes usually have the characteristics of volatility and strong aroma. β-Myrcene and its isomer (E)-β-ocimene are typical acyclic monoterpenes. They are high-value monoterpenes that have been widely applied in foods, cosmetics, and medicines. However, large-scale commercial production of β-myrcene and (E)-β-ocimene is restricted by their production method that mainly involves extraction from plant essential oils. Currently, an alternative synthetic route utilizing an engineered microbial platform was proposed for effective production. This study used a Saccharomyces cerevisiae strain previously constructed for squalene production as the starting strain. Farnesyl diphosphate synthase (Erg20) expression was weakened by promoter replacement and screened for optimal myrcene synthase (MS) and ocimene synthase (OS) activities. In the resulting S. cerevisiae engineered for β-myrcene and (E)-β-ocimene synthesis, titers of β-myrcene and (E)-β-ocimene were enhanced by a fusion expressing a mutant Erg20* with the obtained monoterpene synthase and optimizing the added solvent in a two-phase fermentation system. Finally, by scaling up in a 5-L fermenter, 8.12 mg/L of β-myrcene was obtained, which was first reported in yeast, and 34.56 mg/L of (E)-β-ocimene was obtained, which is the highest reported to date. This study provides a new synthesis route for β-myrcene and (E)-β-ocimene.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13205-023-03818-2.

Biomolecular and cellular effects in skin wound healing: the association between ascorbic acid and hypoxia-induced factor

The skin serves as a barrier to protect the body from environmental microorganisms and is the largest tissue of the body and any damage must be quickly and effectively repaired. The fundamental purpose of dermal fibroblasts is to produce and secrete extracellular matrix, which is crucial for healing wounds. The production of collagen by dermal fibroblasts requires the cofactor ascorbic acid, a free radical scavenger. In skin wounds, the presence of Ascorbic acid (AA) decreases the expression of pro-inflammatory factors and increases the expression of wound-healing factors. In addition, AA plays an important role in all three phases of wound healing, including inflammation, proliferation, and regeneration. On the other hand, growing evidence indicates that hypoxia improves the wound healing performance of mesenchymal stem cell-conditioned medium compared to the normoxic-conditioned medium. In a hypoxic-conditioned medium, the proliferation and migration of endothelial cells, fibroblasts, and keratinocytes (important cells in accelerating skin wound healing) increase. In this review, the role of AA, hypoxia, and their interactions on wound healing will be discussed and summarized by the in vitro and in vivo studies conducted to date.

Emergence of New Concepts in Skin Physiopathology through the Use of in vitro Human Skin Explants Models

BACKGROUND

This review summarizes uses and new applications for dermatological research of in vitro culture models of human skin explants (HSEs). In the last decade, many innovations have appeared in the literature and an exponential number of studies have been recorded in various fields of application such as process culture engineering, stem cell extractions methodology, or cell-to-cell interaction studies under physiological and pathological conditions, wound-healing, and inflammation. Most studies also concerned pharmacology, cosmetology, and photobiology. However, these topics will not be considered in our review.

SUMMARY

A better understanding of the mechanisms driving intercellular relationships, at work in the maintenance of 3D tissue architectures has led to the improvement of cell culture techniques. Many papers have focused on the physiological ways that govern in vitro tissue maintenance of HSEs. The analysis of the necessary mechanical stress, intercellular and cell-matrix interactions, allows the maintenance and prolonged use of HSEs in culture for up to 15 days, regardless of the great variability of study protocols from one laboratory to another and in accordance with the objectives set. Because of their close similarities to fresh skin, HSEs are increasingly used to study skin barrier repair and wound healing physiology. Easy to use in co-culture, this model allows a better understanding of the connections and interactions between the peripheral nervous system, the skin and the immune system. The development of the concept of an integrated neuro-immuno-cutaneous system at work in skin physiology and pathology highlighted by this article represents one of the new technical challenges in the field of in vitro culture of HSE. This review of the literature also reveals the importance of using such models in pathology. As sources of stem cells, HSEs are the basis for the development of new tissue engineering models such as organoids or optical clearing tissues technology. This study identifies the main advances and cross-cutting issues in the use of HSE.

Healing Effect of a Nano-Functionalized Medical-Grade Honey for the Treatment of Infected Wounds

Based on the qualities of Ulmo honey (Eucryphia cordifolia), a medical-grade honey (Ulmoplus®) has been developed. Relevant to this, the use of copper represents an emerging therapy for the treatment of wounds. Therefore, the aim of this study was to see how this medical-grade honey with copper nanoparticles (CuNPs) helped to heal infected or non-infected wounds. Twenty-four guinea pigs (Cavia porcellus) were divided into four groups for phase 1 (without and with infection, U + F1 and U + F2), and two groups for phase 2 (selected formulation, without and with infection, U + F2NI and U + F2I). Bacteriological and histopathological studies, collagen fibers content evaluation, and stereological analysis were performed. The selected formulation displayed the same antibacterial potency as Ulmoplus®, indicating that this medical-grade honey by itself can be used as an antibacterial agent. However, the evaluation of collagen content demonstrated a significant increase in fibroblast and type III collagen fibers for infected and uninfected groups, which correlated with the histopathological study. Therefore, it is correct to affirm that adding CuNPs to Ulmoplus® improved the maturation of collagen fibers. Finally, polymorphonuclear cells presented similar values between experimental groups, which would indicate that the formulation under study was able to regulate the inflammatory process despite their infectious condition.

Healing Effect of a Nano-Functionalized Medical-Grade Honey for the Treatment of Infected Wounds

Based on the qualities of Ulmo honey (Eucryphia cordifolia), a medical-grade honey (Ulmoplus®) has been developed. Relevant to this, the use of copper represents an emerging therapy for the treatment of wounds. Therefore, the aim of this study was to see how this medical-grade honey with copper nanoparticles (CuNPs) helped to heal infected or non-infected wounds. Twenty-four guinea pigs (Cavia porcellus) were divided into four groups for phase 1 (without and with infection, U + F1 and U + F2), and two groups for phase 2 (selected formulation, without and with infection, U + F2NI and U + F2I). Bacteriological and histopathological studies, collagen fibers content evaluation, and stereological analysis were performed. The selected formulation displayed the same antibacterial potency as Ulmoplus®, indicating that this medical-grade honey by itself can be used as an antibacterial agent. However, the evaluation of collagen content demonstrated a significant increase in fibroblast and type III collagen fibers for infected and uninfected groups, which correlated with the histopathological study. Therefore, it is correct to affirm that adding CuNPs to Ulmoplus® improved the maturation of collagen fibers. Finally, polymorphonuclear cells presented similar values between experimental groups, which would indicate that the formulation under study was able to regulate the inflammatory process despite their infectious condition.

A systematic review of natural products for skin applications: Targeting inflammation, wound healing, and photo-aging

BACKGROUND

Every day the skin is constantly exposed to several harmful factors that induce oxidative stress. When the cells are incapable to maintain the balance between antioxidant defenses and reactive oxygen species, the skin no longer can keep its integrity and homeostasis. Chronic inflammation, premature skin aging, tissue damage, and immunosuppression are possible consequences induced by sustained exposure to environmental and endogenous reactive oxygen species. Skin immune and non-immune cells together with the microbiome are essential to efficiently trigger skin immune responses to stress. For this reason, an ever-increasing demand for novel molecules capable of modulating immune functions in the skin has risen the level of their development, particularly in the field of natural product-derived molecules.

PURPOSE

In this review, we explore different classes of molecules that showed evidence in modulate skin immune responses, as well as their target receptors and signaling pathways. Moreover, we describe the role of polyphenols, polysaccharides, fatty acids, peptides, and probiotics as possible treatments for skin conditions, including wound healing, infection, inflammation, allergies, and premature skin aging.

METHODS

Literature was searched, analyzed, and collected using databases, including PubMed, Science Direct, and Google Scholar. The search terms used included "Skin", "wound healing", "natural products", "skin microbiome", "immunomodulation", "anti-inflammatory", "antioxidant", "infection", "UV radiation", "polyphenols", "polysaccharides", "fatty acids", "plant oils", "peptides", "antimicrobial peptides", "probiotics", "atopic dermatitis", "psoriasis", "auto-immunity", "dry skin", "aging", etc., and several combinations of these keywords.

RESULTS

Natural products offer different solutions as possible treatments for several skin conditions. Significant antioxidant and anti-inflammatory activities were reported, followed by the ability to modulate immune functions in the skin. Several membrane-bound immune receptors in the skin recognize diverse types of natural-derived molecules, promoting different immune responses that can improve skin conditions.

CONCLUSION

Despite the increasing progress in drug discovery, several limiting factors need future clarification. Understanding the safety, biological activities, and precise mechanisms of action is a priority as well as the characterization of the active compounds responsible for that. This review provides directions for future studies in the development of new molecules with important pharmaceutical and cosmeceutical value.

Topical Application of No-Ozone Cold Plasma in Combination with Vitamin C Reduced Skin Redness and Pigmentation of UV-Irradiated Mice

Ultraviolet (UV) is the main cause of sunburn on the skin as it induces erythema and accelerates pigmentation. Vitamin C is one of the most frequently used compounds to reduce UV-induced skin pigmentation, but it has limitations in absorption through the skin. In this study, we tested whether a no-ozone cold plasma (NCP) treatment can improve UV-irradiated skin by helping the action of Vitamin C. For this, among five groups of HRM-2 hairless mice, four groups of mice were subjected to UVB irradiation, and three groups of UVB-treated mice were treated with NCP, Vitamin C, and NCP + Vitamin C, respectively. For evaluating the effect of each treatment, the melanin and erythema index was measured during animal experiments. Histological changes were monitored by performing H&E and MTS and IHC against tyrosinase and melanin. As a result, the naturally recovered mice showed a 28-point decrease in the melanin index, whereas a decrease of around 88, 74.3, and 106 points was detected in NCP-, Vitamin C-, and NCP + vitamin C-treated mice, respectively. Likewise, only a 39-point reduction in the erythema index was monitored in naturally recovered mice, but the NCP-, vitamin C-, and NCP + vitamin C-treated mice showed a 87.3-, 77-, and 111-point reduction, respectively. Interestingly, the skin tissues of the mice treated with NCP in combination with Vitamin C mostly recovered from UVB-induced damage. Altogether, this study elucidated the beneficial effect of the treatment of NCP in combination with Vitamin C on the UVB-irradiated skin, which might be helpful for treating sunburn on the skin.

Chitosan-Coated Niosomes Loaded with Ellagic Acid Present Antiaging Activity in a Skin Cell Line

The polyphenol compound ellagic acid (EA) extracted from pomegranate has potential bioactivity against different types of chronic diseases. Skin aging is a long-term physiological process caused by many environmental factors, the most important of which is exposure to sun ultraviolet (UV) radiation. UV-induced chronic photodamage of the skin results in extrinsic aging. This study aimed to evaluate the photoprotective effects of EA on the human fibroblast skin cell line HFB4 and investigate its capacity to protect collagen from UV-induced deterioration. EA was encapsulated into chitosan-coated niosomes to reduce the skin aging effect of UV radiation in vitro. The tested formulations (niosomes loaded with EA and chitosan-coated niosomes loaded with EA) were characterized using transmission electron microscopy, dynamic light scattering, and scanning electron microscopy. Furthermore, the in vitro release of EA was determined. The HFB4 cell line samples were split into five groups: control, UV, UV-EA, UV-NIO-EA, and UV-CS-NIO-EA. UV irradiation was applied to the cell line groups via a UV-emitting lamp for 1 h, and then cell viability was measured for each group. The expression of genes implicated in skin aging (Co1A1, TERT, Timp3, and MMP3) was also assessed to quantify the impact of the loaded EA. The findings showed that EA-loaded chitosan-coated niosomes improved cell survival, upregulated Col1A1, TERT, and Timp3 genes, and downregulated MMP3. Thus, nanoparticles encapsulating EA are potent antioxidants that can preserve collagen levels and slow down the aging process in human skin.

Effects of Oral Collagen for Skin Anti-Aging: A Systematic Review and Meta-Analysis

This paper presents a systematic review and meta-analysis of 26 randomized controlled trials (RCTs) involving 1721 patients to assess the effects of hydrolyzed collagen (HC) supplementation on skin hydration and elasticity. The results showed that HC supplementation significantly improved skin hydration (test for overall effect: Z = 4.94, p < 0.00001) and elasticity (test for overall effect: Z = 4.49, p < 0.00001) compared to the placebo group. Subgroup analyses demonstrated that the effects of HC supplementation on skin hydration varied based on the source of collagen and the duration of supplementation. However, there were no significant differences in the effects of different sources (p = 0.21) of collagen or corresponding measurements (p = 0.06) on skin elasticity. The study also identified several biases in the included RCTs. Overall, the findings suggest that HC supplementation can have positive effects on skin health, but further large-scale randomized control trials are necessary to confirm these findings.

Regulation of Ethanol Assimilation for Efficient Accumulation of Squalene in Saccharomyces cerevisiae

Squalene is a triterpene that can be obtained from fish and plant oils. It is important in cosmetics and vaccines and is a precursor for many high-value terpenes and steroids. In order to increase squalene accumulation, the mevalonate pathway was systematically enhanced. Accumulation of squalene tended to increase when ethanol was added as a carbon source during fermentation, but a high concentration of ethanol affected both the strain growth and accumulation of products. By overexpressing the key trehalose synthesis gene TPS1 and the heat shock protein gene HSP104, the content of trehalose by Saccharomyces cerevisiae (S. cerevisiae) was enhanced, and stress caused by ethanol was relieved. The OD₆₀₀ value of the modified S. cerevisiae strain was increased by 80.2%, its ethanol tolerance was increased to 30 g/L, and it retained excellent activity with 50 g/L ethanol. After optimizing the fermentation conditions, the squalene titer in a 5 L bioreactor reached 27.3 g/L and the squalene content was 650 mg/g dry cell weight, the highest squalene production parameters reported to date for a microorganism.

Exploring the potential of Halomonas levan and its derivatives as active ingredients in cosmeceutical and skin regenerating formulations

Demand on natural products that contain biological ingredients mimicking growth factors and cytokines made natural polysaccharides popular in pharmaceutical and cosmetic industries. Levan is the β-(2-6) linked, nontoxic, biocompatible, water-soluble, film former fructan polymer that has diverse applications in pharmacy and cosmeceutical industries with its moisturizing, whitening, anti-irritant, anti-aging and slimming activities. Driven by the limited reports on few structurally similar levan polymers, this study presents the first systematic investigation on the effects of structurally different extremophilic Halomonas levan polysaccharides on human skin epidermis cells. In-vitro experiments with microbially produced linear Halomonas levan (HL), its hydrolyzed, (hHL) and sulfonated (ShHL) derivatives as well as enzymatically produced branched levan (EL) revealed increased keratinocyte and fibroblast proliferation (113-118 %), improved skin barrier function through induced expressions of involucrin (2.0 and 6.43 fold changes for HL and EL) and filaggrin (1.74 and 3.89 fold changes for hHL and ShHL) genes and increased type I collagen (2.63 for ShHL) and hyaluronan synthase 3 (1.41 for HL) gene expressions together with fast wound healing ability within 24 h (100 %, HL) on 2D wound models clearly showed that HL and its derivatives have high potential to be used as natural active ingredients in cosmeceutical and skin regenerating formulations.

Effects of hypobaric hypoxia during a simulated ultra-long-haul flight on inflammation and regeneration after muscle trauma and muscle trauma-hemorrhagic shock

INTRODUCTION/AIMS

Because wounded warfighters or trauma victims may receive en route care to the closest medical facility via airplane transport, we investigated the effects of extended mild hypobaric hypoxia (HB), the environmental milieu of most airplanes, on inflammation and regeneration after muscle trauma or monotrauma (MT) and muscle trauma-hemorrhagic shock or polytrauma (PT).

METHODS

Male C57BL/6N mice were assigned to one of six groups pertaining to injury (control/uninjured, MT, and PT) and atmospheric pressure exposure (HB and normobaric normoxia, NB). Body mass, blood and muscle leukocyte number by flow cytometry, immunohistochemistry, or both, and the muscle relative mRNA level of selected genes involved in inflammation and muscle regeneration were examined at ~1.7, 4, 8, and 14 days post trauma (dpt). At 14 dpt, the proportion of smaller- and larger-sized myofibers at the regenerating site of MT mice was determined.

RESULTS

Greater body mass loss, an increased number of blood and muscle leukocytes, and differential muscle relative mRNA levels were observed in MT and PT groups compared to controls. The MT+HB or PT+HB mice demonstrated more body mass loss and altered relative mRNA level than the corresponding NB mice. Additionally, a subgroup of MT+HB mice demonstrated a greater proportion of smaller myofibers (250 to 500 μm² ) than MT+NB mice at 14 dpt.

DISCUSSION

HB exposure after muscle trauma alone may prolong regeneration. Following HB exposure, therapies that promote oxygenation may be needed during this muscle recovery.

A Bio-Therapeutically Squalene

Although the skin tissue on our bodies is a well-organized structure with high biomechanical properties like tensile strength and friction, we have all experienced various types of wounds throughout our lives owing to numerous etiological factors. In the general population, it is a substantial source of morbidity. For instance, in the case of burnt skin tissue, self-healing is in fact a large and challenging barrier to tissue regeneration. Squalene is a bioactive triterpene that occurs naturally and plays a key role in the process of making sterols. The most well-known source of squalene is shark liver oil. Vegetable oils may contain squalene in a range of concentrations. They have been extracted using a variety of techniques, including supercritical carbon dioxide, microwave, ultrasonic, cold press, and traditional Soxhlet extractions. In vitro and in animal models, these substances have been demonstrated to have anticancer, antioxidant, drug carrier, detoxifier, skin moisturising, and emollient effects.

Prevalence and prognostic significance of vitamin C deficiency in patients with acute upper gastrointestinal bleeding: a prospective cohort study

BACKGROUND

Vitamin C is an essential dietary nutrient important for collagen synthesis, including within the gastrointestinal tract.

AIM

We aimed to document the prevalence of Vitamin C deficiency (VCD) in patients who present with upper gastrointestinal bleeding (UGIB) and its association with clinical outcomes.

METHODS

We conducted a prospective cohort study of patients presenting with UGIB. Fasting Vitamin C levels were collected at admission. Primary outcomes were the prevalence of VCD (Vitamin C level <23 μmol/L, severe VCD < 12 μmol/L) and a composite outcome of adverse events, stratified by VCD status. Secondary outcomes were prolonged hospitalisation and the need for ICU admission.

RESULTS

A total of 227 patients were included (mean age 64.5 years, males 63.9%). VCD was identified in 74 (32.6%) and severe deficiency in 32 (14.1%) patients. VCD was associated with a higher composite endpoint of AE (45.9% vs 24.8%, p < 0.01), higher in-hospital mortality (9.5% vs 1.3%, p < 0.01), increased prolonged admissions (62.2% versus 47.1%, p = 0.03) and increased rebleeding (17.6% vs 7.8%, p = 0.03), compared with patients with normal Vitamin C levels. Multivariate logistic regression models showed that VCD was independently associated with the composite endpoint of AE.

CONCLUSION

VCD is highly prevalent in patients with UGIB and associated with poorer outcomes, including higher mortality, rebleeding and length of stay. Interventional studies are required to determine the impact of early Vitamin C supplementation on clinical outcomes.

Ascorbic Acid (Vitamin C) as a Cosmeceutical to Increase Dermal Collagen for Skin Antiaging Purposes: Emerging Combination Therapies

Ascorbic acid (AA) is an essential nutrient and has great potential as a cosmeceutical that protects the health and beauty of the skin. AA is expected to attenuate photoaging and the natural aging of the skin by reducing oxidative stress caused by external and internal factors and by promoting collagen gene expression and maturation. In this review, the biochemical basis of AA associated with collagen metabolism and clinical evidence of AA in increasing dermal collagen and inhibiting skin aging were discussed. In addition, we reviewed emerging strategies that have been developed to overcome the shortcomings of AA as a cosmeceutical and achieve maximum efficacy. Because extracellular matrix proteins, such as collagen, have unique amino acid compositions, their production in cells is influenced by the availability of specific amino acids. For example, glycine residues occupy 1/3 of amino acid residues in collagen protein, and the supply of glycine can be a limiting factor for collagen synthesis. Experiments showed that glycinamide was the most effective among the various amino acids and amidated amino acids in stimulating collagen production in human dermal fibroblasts. Thus, it is possible to synergistically improve collagen synthesis by combining AA analogs and amino acid analogs that act at different stages of the collagen production process. This combination therapy would be useful for skin antiaging that requires enhanced collagen production.

Comparative Studies on Carbon Paste Electrode Modified with Electroactive Polyamic Acid and Corresponding Polyimide without/with Attached Sulfonated Group for Electrochemical Sensing of Ascorbic Acid

In this study, electroactive poly (amic acid) (EPAA) and corresponding polyimide (EPI) without or with a sulfonated group (i.e., S-EPAA, and S-EPI) were prepared and applied in electrochemical sensing of ascorbic acid (AA). The electroactive polymers (EAPs) containing EPAA/EPI and S-EPAA/S-EPI were synthesized by using an amine-capped aniline trimer (ACAT) and sulfonated amine-capped aniline trimer (S-ACAT) as an electroactive segment that controlled the redox capability and influenced the degree of sensitivity of the EAPs towards AA. Characterization of the as-prepared EAPs was identified by FTIR spectra. The redox capability of the EAPs was investigated by electrochemical cyclic voltammetric studies. It should be noted that the redox capability of the EAPs was found to show the following trend: S-EPAA > S-EPI > EPAA > EPI. For the electrochemical sensing studies, a sensor constructed from an S-EPAA-modified carbon paste electrode (CPE) demonstrated 2-fold, 1.27-fold, and 1.35-fold higher electro-catalytic activity towards the oxidation of AA, compared to those constructed using a bare CPE, S-EPI-, and EPI/EPAA-modified CPE, respectively. The higher redox capability of S-EPAA-modified CPE exhibited a good electrochemical response towards AA at a low oxidative potential, with good stability and selectivity. Moreover, an electrochemical sensor constructed from S-EPAA-modified CPE was found to reveal better selectivity for a tertiary mixture of AA/DA/UA, as compared to that of EPI-modified, EPAA-modified and S-EPI-modified CPE, based on a series of differential pulse voltammograms.

Human organ rejuvenation by VEGF-A: Lessons from the skin

Transplanting aged human skin onto young SCID/beige mice morphologically rejuvenates the xenotransplants. This is accompanied by angiogenesis, epidermal repigmentation, and substantial improvements in key aging-associated biomarkers, including ß-galactosidase, p16^ink4a, SIRT1, PGC1α, collagen 17A, and MMP1. Angiogenesis- and hypoxia-related pathways, namely, vascular endothelial growth factor A (VEGF-A) and HIF1A, are most up-regulated in rejuvenated human skin. This rejuvenation cascade, which can be prevented by VEGF-A-neutralizing antibodies, appears to be initiated by murine VEGF-A, which then up-regulates VEGF-A expression/secretion within aged human skin. While intradermally injected VEGF-loaded nanoparticles suffice to induce a molecular rejuvenation signature in aged human skin on old mice, VEGF-A treatment improves key aging parameters also in isolated, organ-cultured aged human skin, i.e., in the absence of functional skin vasculature, neural, or murine host inputs. This identifies VEGF-A as the first pharmacologically pliable master pathway for human organ rejuvenation in vivo and demonstrates the potential of our humanized mouse model for clinically relevant aging research.

The Molecular Mechanism of Propylene Glycol Monocaprylate on Skin Retention: Probing the Dual Roles on the Molecular Mobility and Collagen Connection in Roflumilast Cream

The present work was to construct a roflumilast (ROF) cream for the treatment of psoriasis and clarify the dual roles of propylene glycol monocaprylate (PGM) in both molecular mobility of the cream, and drug-skin miscibility via drug-PGM-ceramide and drug-PGM-collagen intermolecular interaction. The cream formulation was screened through the stability study and in vitro skin administration study, optimized by Plackett-Burman and Box-Behnken design, and finally verified by the in vivo tissue distribution study. PGM demonstrated a significant drug skin retention enhancement effect (R_{max in vivo} = 19.5 μg/g). It increased the molecular mobility of the oil phase of the cream by decreasing the molecular interaction of oil molecules proven by the rheology study (E_c = 3.73 × 10^-4 mJ·m^-3). More importantly, because of the good stratum corneum (SC) compatibility (∆H =  - 403.88 J/g), PGM promoted an orderly flow of SC lipids (X-ray scattering, ΔLPP = 1.18 nm) and entered the viable epidermis/dermis (VE/DE) in large quantities (R_PGM = 1186 μg/g), acting as a bridge to connect the drug to collagen through two H-bonds (Length_H-bond = 2.846 Å and 3.313 Å), thus increasing the miscibility of drug and VE/DE significantly (∆H =  - 310.10 J/g, E_mix = 21.66 kcal/mol). In this study, a ROF cream was developed successfully and the effect of PGM on the skin retention was clarified at molecular level.

Effect of Penetration Enhancers and Safety on the Transdermal Delivery of Apremilast in Skin

The poor water solubility of apremilast (APR) is the main impediment to the penetration of the drug through the skin barrier. The objective of this study was to evaluate the permeability of APR in different solutions enriched with penetration promoters in ex vivo samples of human skin, and additionally assess its tolerance in vivo. To this end, APR solutions with 5% promoter were developed, and the drug's ability to penetrate human abdominal skin samples was evaluated; the coefficients of permeability, cumulated amounts permeated, and flow were some of the parameters evaluated; likewise, the in vitro and in vivo tolerance of the solutions was evaluated. The results obtained showed that the solutions containing squalene as a promoter improved the penetration of APR compared to the other promoters evaluated; in the same way, on an in vitro scale in HaCaT cells, the promoters were not toxic, finding a cell viability greater than 80% at the different dilutions evaluated. In the in vivo tests carried out with the solution that presented the best results (APR-Squalene solution), it was observed that it does not cause irritation or erythema on the skin after its colorimetric and histological evaluation of the dorsal region of rats after its application. Squalene becomes an excellent candidate to improve the permeability of the drug in the case of the development of a topical formulation; in addition, it was confirmed that this penetration enhancer is neither toxic nor irritating when in contact with the skin in in vivo tests.

Double Nutri (Liposomal Encapsulation) Enhances Bioavailability of Vitamin C and Extends Its Half-Life in Plasma

Vitamin C is an important antioxidant in the human body that plays a role in many body functions. Liposomal encapsulation is a technology commonly used in food processing and medicine. This study determines whether Double Nutri (liposomal encapsulation) increases the absorption rate for vitamin C supplementation. Subjects enrolled in this study took vitamin C without liposome; then, 14 d washout was given with liposomal process A vitamin C. After 14 d washout, the subjects took liposomal process B vitamin C (Double Nutri) was given. After taking the test sample, the vitamin C concentration in venous blood was measured from the baseline (0 h), 0.5, 1, 2, 3, 4, and 8 h. Eleven healthy subjects were recruited for three tests. The vitamin C concentration for liposomal process B vitamin C (Double Nutri) group is higher (7.26±3.52, p<0.01) than that for the liposomal process A vitamin C group (6.41±3.80, p<0.05) and for vitamin C without liposome (2.21±4.07). This shows that Double Nutri has better bioavailability and can last up in the body to 8 hours. In addition, this study shows that Double Nutri increases the half-life of vitamin C in plasma and has higher bioavailability.

Lycopene ameliorates skin aging by regulating the insulin resistance pathway and activating SIRT1

Lycopene could reverse insulin resistance through SIRT1 during skin aging and promotes microcirculation via the improvement of microvascular neovascularization to protect aging skin.

Detachable dissolvable microneedles: intra-epidermal and intradermal diffusion, effect on skin surface, and application in hyperpigmentation treatment

Delivering bioactive compounds into skin tissue has long been a challenge. Using ex vivo porcine and rat skins, here we demonstrate that a detachable dissolvable microneedle (DDMN) array, a special dissolvable microneedle that allows needle detachment from the base within 2 min post administration, can effectively embed a model compound into epidermis and dermis. Diffusion of the compound from the needle embedding sites to the nearby skin tissue is demonstrated at various post administration periods. The relationship between the time that a conventional dissolvable microneedle array is left on skin without needle detachment from the base and the degree of skin surface abrasion at each microneedle penetration spot is also demonstrated on skin of human volunteers. Co-loading glutathione with vitamin C (vitC) can stabilize vitC in the DDMN. DDMN loaded with vitC and glutathione can help erasing post-acne-hyperpigmentation spots.

Topical delivery of l-ascorbic acid spanlastics for stability enhancement and treatment of UVB induced damaged skin

l-Ascorbic acid (LAA) is considered a powerful antioxidant that protects skin from premature aging. Maintaining the stability of vitamin C remains the biggest challenge in cosmeceuticals. Our main aim is the entrapment of high dose of vitamin C in spanlastic vesicles to provide maximum stability and efficacy. LAA-loaded spanlastics were prepared by ethanol injection method and were characterized for entrapment efficiency (EE%), particles size (PS), polydispersity index (PDI), zeta potential, deformability index (DI) and in vivo skin permeation. Selected spanlastics formula composed of span 60 and tween 60 (5:1) showed highest EE% of 89.77 ± 3.61% (w/w), high deformability of 11.13 ± 1.145 as well as good physical and chemical stability for 6 months. Improved drug penetration into stratum corneum (SC) was obtained from spanlastics compared to topical LAA solution. Quantitative real time PCR revealed that MMP2 and MMP9 levels were significantly suppressed in response to LAA spanlastics treated rats by 30.4% and 65.3%, respectively, when compared to the control group after exposure to UV irradiation. Results were confirmed by western blot analysis. Histopathological study of rat skin after UV irradiation revealed that application of LAA-loaded spanlastics provided the highest skin protection compared to UVB and LAA solution treated group which was evident by the normal thick epidermal morphology and the densely arranged dermal collagen fibers. LAA-loaded spanlastics successfully improved LAA stability, skin permeation and antioxidant protection against skin photodamage.

Facial Treatment with 3-O-Cetyl Ascorbic Acid for Improvement of Skin Texture: Uptake, Effectiveness, and In Vitro Carcinogenicity Assessment

Ascorbic acid (AA) is a water-soluble vitamin that is found at high concentrations in normal skin. The important and well-known benefits of using AA in skin health include the stimulation of collagen synthesis and the assistance of protection against photo-oxidative damages. To maintain stability and improve drug delivery to the active site, a variety of AA derivatives have been chemically synthesized. Among these compounds, we focus here on a lipophilic derivative, 3-O-cetyl ascorbic acid (3-CetylAA), which remains poorly characterized for cosmetic applications. Uptake analysis in three healthy human volunteers’ skin was conducted using a serial tape-stripping technique detecting 3-CetylAA (on average, 128 ± 27 pmol per µg) in the stratum corneum after a 5-h topical treatment when treated with 25 mM 3-CetylAA-containing cream for 13 days twice daily and continuously. Time-of-flight secondary ion mass spectrometry (ToF-SIMS) imaging of vertical cryosections of pig skin revealed the presence of 3-CetylAA in the epidermal layer after topical treatment with 3-CetylAA-containing cream. In sun-exposed human skin, 3-CetylAA improved the texture after treatment with 25 mM 3-CetylAA-containing cream for 4 weeks or more when used twice daily or continuously. An in vitro transformation assay using BALB/c 3T3 A31-1-1 cells demonstrated that 10 µM 3-CetylAA, which is the same concentration exhibited in vitro biological activities in another lipophilic AA derivative, 2-O-octadecyl ascorbic acid, was non-carcinogenic and did not potentiate the UVC-induced transformation frequency when applied for 3 days after UVC irradiation. These results demonstrate that 3-CetylAA is a promising candidate as a lipophilic derivative of AA for cosmetic purposes.

Synthesis and Cytotoxicity Study of Magnetite Nanoparticles Coated with Polyethylene Glycol and Sorafenib-Zinc/Aluminium Layered Double Hydroxide

In the last two decades, the development of novel approaches for cancer treatment has attracted intense attention due to the growing number of patients and the inefficiency of the available current conventional treatments. In this study, superparamagnetic iron oxide nanoparticles (SPIONs) were synthesized by the co-precipitation method in an alkaline medium. Then the nanoparticles were chemically modified by coating them with polyethylene glycol (PEG) and sorafenib (SO)-zinc/aluminum layered double hydroxide (ZLDH) to improve their biocompatibility. The SPIONs and their coated and drug-loaded nanoparticles, M-PEG-SO-ZLDH are of the crystalline phase with the presence of C, O, Al, Fe, Cl, Zn in the latter, indicating the presence of the coating layers on the surface of the SPIONs. The superparamagnetic properties of the bare SPIONs were found to be reduced but retained in its coated drug delivery nanoparticles, M-PEG-SO-ZLDH. The latter has an average particle size of 16 nm and the release of the drug from it was found to be governed by the pseudo-second-order kinetic. The cytotoxicity and biocompatibility evaluation of the drug-loaded magnetic nanoparticles using 3T3 and HepG2 cells using the diphenyltetrazolium bromide (MTT) assays shows that the synthesized nanoparticles were less toxic than the pure drug. This preliminary study indicates that the prepared nanoparticles are suitable to be used for the drug delivery system.