Applications of Engineered Skin Tissue for Cosmetic Component and Toxicology Detection.

The scale of the cosmetic market is increasing every day. There are many safety risks to cosmetics, but they benefit people at the same time. The skin can become red, swollen, itchy, chronically toxic, and senescent due to the misuse of cosmetics, triggering skin injuries, with contact dermatitis being the most common. Therefore, there is an urgent need for a system that can scientifically and rationally detect the composition and perform a toxicological assessment of cosmetic products. Traditional detection methods rely on instrumentation and method selection, which are less sensitive and more complex to perform. Engineered skin tissue has emerged with the advent of tissue engineering technology as an emerging bioengineering technology. The ideal engineered skin tissue is the basis for building good in vitro structures and physiological functions in this field. This review introduces the existing cosmetic testing and toxicological evaluation methods, the current development status, and the types and characteristics of engineered skin tissue. The application of engineered skin tissue in the field of cosmetic composition detection and toxicological evaluation, as well as the different types of tissue engineering scaffold materials and three-dimensional (3D) organoid preparation approaches, is highlighted in this review to provide methods and ideas for constructing the next engineered skin tissue for cosmetic raw material component analysis and toxicological evaluation.

Mangrove plants are promising bioindicator of coastal atmospheric microplastics pollution.

Plastics are commonly used by society and their break down into millimeter-sized bits known as microplastics (MPs). Due to the possibility of exposure, reports of them in atmospheric deposition, indoor, and outdoor air have sparked worry for public health. In tropical and subtropical regions all throughout the world, mangroves constitute a distinctive and significant type of coastal wetlands. Mangrove plants are considered to have the effect of accumulating sediment MPs, but the sedimentation of atmospheric MPs has not been reported. In this study, we illustrated the characteristics, abundance and spatial distribution of MPs in different species of mangrove leaves along the Seagull Island in Guangzhou. MPs samples from leaves in five species showed various shapes, colors, compositions, sizes and abundance. Acanthus ilicifolius had an average fallout rate of 1223 items/m2/day which has the highest abundance of MPs in all samples. Four shapes of MPs were found in all leaves surfaces including fiber, fragment, pellet, and film, with fiber is the most. The dominant types of MPs in all leaves were cellulose and rayon. Most of the total MPs size were smaller than 2 mm. Clearly, the microstructures of each species leaf surfaces had an impact on its ability to retain MPs. The plants rough blade surfaces and big folds or gullies caused more particles to accumulate and had a higher MPs retention capacity. Overall, our study contributes to a better knowledge of the condition of MPs pollution in atmosphere and the connection between leaves structure and the retention of MPs, which indicates that mangrove plants are promising bioindicator of coastal atmospheric MPs pollution.

Combined effects of microplastics and antibiotic-resistant bacteria on Daphnia magna growth and expression of functional genes.

Microplastics could act as vectors for the transport of harmful bacteria, such as pathogens and antibiotic resistance bacteria (ARB), but their combined effects have not been reported yet. Here, ARB Shigella flexneri with sulfonamides resistance and micro-polystyrene (micro-PS) were used to investigate their possible combined effects on the growth and expression of functional genes in Daphnia magna. Results showed that micro-PS colonized with S. flexneri were ingested by D. magna and blocked in their intestine after 24 h exposure. Changes were observed in the life history and morphology of D. magna, as well as the expression of functional genes in all treatments, but with no difference in the survival rate. We also determined the expression of six functional genes involved in energy and metabolism (arginine kinase, AK) and oxidative stress response (thioredoxin reductase, TRxR, catalase, CAT, and glutathione S-transferases, GSTs), as well as in growth, development and reproduction (vitellogenin, Vtg1 and ecdysone receptor, EcR). AK and Vtg1 did not show significant differences, however, EcR was down-regulated and the other three genes (TRxR, CAT, GSTs) were up-regulated in the combined-treated group. Antibiotic resistance gene (ARGs) sul1 was detected when exposed to micro-PS colonized with S. flexneri., suggesting that D. magna could acquire resistance genes through microplastic biofilms. These results indicated that MPs could act as a carrier of ARB to transfer ARGs into D. magna, and affect the life history, morphology, and the expression of related functional genes of D. magna, to adapt to the stress caused by MPs and ARB.

Biological Degradation of Plastics and Microplastics: A Recent Perspective on Associated Mechanisms and Influencing Factors.

Plastic and microplastic pollution has caused a great deal of ecological problems because of its persistence and potential adverse effects on human health. The degradation of plastics through biological processes is of great significance for ecological health, therefore, the feasibility of plastic degradation by microorganisms has attracted a lot of attention. This study comprises a preliminary discussion on the biodegradation mechanism and the advantages and roles of different bacterial enzymes, such as PET hydrolase and PCL-cutinase, in the degradation of different polymers, such as PET and PCL, respectively. With a particular focus on their modes of action and potential enzymatic mechanisms, this review sums up studies on the biological degradation of plastics and microplastics related to mechanisms and influencing factors, along with their enzymes in enhancing the degradation of synthetic plastics in the process. In addition, biodegradation of plastic is also affected by plastic additives and plasticizers. Plasticizers and additives in the composition of plastics can cause harmful impacts. To further improve the degradation efficiency of polymers, various pretreatments to improve the efficiency of biodegradation, which can cause a significant reduction in toxic plastic pollution, were also preliminarily discussed here. The existing research and data show a large number of microorganisms involved in plastic biodegradation, though their specific mechanisms have not been thoroughly explored yet. Therefore, there is a significant potential for employing various bacterial strains for efficient degradation of plastics to improve human health and safety.

Microplastics in marine-derived traditional Chinese medicine, potential threat to patients.

Microplastics (MPs) contamination is widely found in marine organisms. Marine traditional Chinese medicines (MTCM) are derived from marine organisms, but there are no relevant reports on detecting MPs in MTCM. This study selected samples of MTCM from two representative pharmaceutical companies, Brand F and Brand Z, including mother-of-pearl, stone cassia, seaweed, pumice, oyster, kombu, calcined Concha Arcae, cuttlebone, and clam shell to detect and analyze the presence of MPs. The abundance, type, color, size, and composition of MPs were investigated. Varying degrees of MPs contamination was present in all MTCM. The abundance of MPs in different MTCM ranged from 0.07 to 9.53 items/g. Their type, color, and size are similar, mainly fiber, transparent and size <2 mm. The composition of MPs is primarily made of cotton, cellulose and rayon. This study contributes to the first record of MPs in MTCM. Our results show that microplastic pollution is common in MTCM, which may cause potential risk to patients consuming MTCM.

Sensitivity Enhancement of Soft Capacitive Pressure Sensors Using a Solvent Evaporation-Based Porosity Control Technique.

Soft pressure sensors play a significant role in developing "man-machine" tactile sensation in soft robotics and haptic interfaces. Specifically, capacitive sensors with micro-structured polymer matrices have been explored with considerable effort because of their high sensitivity, wide linearity range, and fast response time. However, the improvement of the sensing performance often relies on the structural design of the dielectric layer, which requires sophisticated microfabrication facilities. This article reports a simple and low-cost method to fabricate porous capacitive pressure sensors with improved sensitivity using the solvent evaporation-based method to tune the porosity. The sensor consists of a porous polydimethylsiloxane (PDMS) dielectric layer bonded with top and bottom electrodes made of elastic conductive polymer composites (ECPCs). The electrodes were prepared by scrape-coating carbon nanotubes (CNTs)-doped PDMS conductive slurry into mold-patterned PDMS films. To optimize the porosity of the dielectric layer for enhanced sensing performance, the PDMS solution was diluted with toluene of different mass fractions instead of filtering or grinding the sugar pore-forming agent (PFA) into different sizes. The evaporation of the toluene solvent allowed the fast fabrication of a porous dielectric layer with controllable porosities. It was confirmed that the sensitivity could be enhanced more two-fold when the toluene to PDMS ratio was increased from 1:8 to 1:1. The research proposed in this work enables a low-cost method of fabricating fully integrated bionic soft robotic grippers with soft sensory mechanoreceptors of tunable sensor parameters.

Postsynaptic glutamate response downregulates within presynaptic exaggerated glutamate release by activating TRPV1 in the spinal dorsal horn.

Activating primary afferent TRPV1-positive (TRPV1+) fibers in the spinal dorsal horn triggers exaggerated glutamate release and induces acute pain. However, whether the glutamate postsynaptic responses on dorsal horn neurons are regulated by excessive glutamate is unknown, largely due to intrinsic technical difficulties. In the present study, capsaicin, a specific TRPV1 agonist, was used to activate TRPV1+ fibers in the spinal dorsal horn. Combining three-dimensional (3-D) holographic photostimulation and whole-cell recordings on acute spinal cord slices from adult rodents, we found that postsynaptic glutamate responses were attenuated when activating TRPV1+ fibers with capsaicin. Electron microscopy and Western blot studies found that postsynaptic GluA1 (a subtype of ionotropic glutamate receptors) on the postsynaptic membrane was decreased by acute capsaicin treatment. Therefore, postsynaptic glutamate receptor occupancy and/or downmodulation may underlie this postsynaptic attenuation. Our data thus clarify a scenario in which postsynaptic glutamate responses are largely downregulated upon TRPV1+ activation, and this change may contribute to homeostasis in the dorsal horn circuit when "acute pain" occurs.

Exosomes Derived From Umbilical Cord Mesenchymal Stem Cells Treat Cutaneous Nerve Damage and Promote Wound Healing.

Wound repair is a key step in the treatment of skin injury caused by burn, surgery, and trauma. Various stem cells have been proven to promote wound healing and skin regeneration as candidate seed cells. Therefore, exosomes derived from stem cells are emerging as a promising method for wound repair. However, the mechanism by which exosomes promote wound repair is still unclear. In this study, we reported that exosomes derived from umbilical cord mesenchymal stem cells (UC-MSCs) promote wound healing and skin regeneration by treating cutaneous nerve damage. The results revealed that UC-MSCs exosomes (UC-MSC-Exo) promote the growth and migration of dermal fibroblast cells. In in vitro culture, dermal fibroblasts could promote to nerve cells and secrete nerve growth factors when stimulated by exosomes. During the repair process UC-MSC-Exo accelerated the recruitment of fibroblasts at the site of trauma and significantly enhanced cutaneous nerve regeneration in vivo. Interestingly, it was found that UC-MSC-Exo could promote wound healing and skin regeneration by recruiting fibroblasts, stimulating them to secrete nerve growth factors (NGFs) and promoting skin nerve regeneration. Therefore, we concluded that UC-MSC-Exo promote cutaneous nerve repair, which may play an important role in wound repair and skin regeneration.

Protective Effects of Grapefruit Essential Oil against Staphylococcus Aureus-Induced Inflammation and Cell Damage in Human Epidermal Keratinocytes.

Staphylococcus aureus (S. aureus) is a common skin pathogenic bacterium, over-colonization can induce skin infections, while its metabolites can also produce irritation to the skin, often accompanied by eczema dermatitis, specific dermatitis and other skin diseases. Grapefruit essential oil is extracted from the fruit of grapefruit (Citrus maxima (Burm) Merr.), a citrus plant that is rich in flavonoids, phenolic acids and high flavanones. Due to its good odor and biological activity such as anti-inflammatory, antibacterial, etc., grapefruit essential oil has been widely used as an additive in food. To evaluate the potential application of grapefruit essential oil as raw materials in cosmetics products and health foods, we developed a cell damage model of skin inflammation stimulated by S. aureus metabolites. Compared to that of lime essential oil, an internal control, we found that grapefruit essential oil could significantly promote HaCaT cells proliferation, reduce reactive oxygen species (ROS) production induced by S. aureus metabolites, inhibit the upregulated expression of IL-1 and COX-2. In the 3D epidermal model, grapefruit essential oil could recover the decreased LOR and FLG contents caused by S. aureus metabolites. These results demonstrated pharmacological evidence for the anti-inflammatory effect of grapefruit essential oil, suggesting a potential application of grapefruit essential oil as cosmetic raw materials for repair and alleviating of skin inflammation caused by S. aureus.

Presynaptic GABAB receptors differentially modulate GABA release from cholecystokinin and parvalbumin interneurons onto CA1 pyramidal neurons: A cell type-specific labeling and activating study.

Combining cell type-specific optogenetics and whole cell recordings on mouse acute hippocampal slices, we compared GABA release from cholecystokinin-expressing (CCK) and parvalbumin-expressing (PV) interneurons onto CA1 pyramidal neurons. Baclofen, a selective GABAB receptor agonist, inhibited GABAergic synaptic transmission greater from CCK terminals, compared to that from PV terminals. The N-type calcium channels on CCK and P/Q-type calcium channels on PV terminals contributed to the GABAB receptor-mediated inhibition, respectively. Our data thus provide direct evidence that GABAB receptors differentially modulate GABA release from CCK and PV interneurons, adding to an increasing list of differences between these two interneuron subtypes in modulating hippocampal pyramidal neurons.

Effects of feeder cells on proliferation of inducible pluripotent stem cells in chicken.

Although inducible pluripotent stem cells (iPSC) have been identified in poultry, the induction efficiency is low, because different culture media, feeder cells and feeder layer treatments affect the efficiency of somatic cell reprogramming. We investigated improvement of the feeder culture system for induction of chicken iPSC by comparing the effects of different types and treatments of feeder cells on the growth and proliferation of chicken iPSC. Mouse embryo fibroblasts (MEF), but not Sandoz inbred mouse-derived thioguanine-resistant and ouabain-buffalo rat cells, were suitable feeder cells that supported proliferation of chicken iPSC. Institute of Cancer Research (ICR) mice, but not Kunming mice, were suitable for preparing MEF that support cell proliferation. Also, MEF feeder cells that had been inactivated by mitomycin C were effective. Leukemia inhibitory factor was not required for chicken iPSC culture when MEF feeder cells were used. The optimal feeder culture system for growth and proliferation of chicken iPSC consisted of MEF feeder cells derived from ICR mice that were inactivated by mitomycin C combined with embryonic germ cell culture medium.

Hypoxic culture of umbilical cord mesenchymal stem cell-derived sEVs prompts peripheral nerve injury repair.

Introduction: Repair and regeneration of the peripheral nerve are important for the treatment of peripheral nerve injury (PNI) caused by mechanical tears, external compression injuries and traction injuries. Pharmacological treatment can promote the proliferation of fibroblasts and Schwann cells (SCs), which longitudinally fill the endoneurial canal and form Bungner's band, helping the repair of peripheral nerves. Therefore, the development of new drugs for the treatment of PNI has become a top priority in recent years. Methods: Here, we report that small extracellular vesicles (sEVs) produced from umbilical cord mesenchymal stem cells (MSC-sEVs) cultured under hypoxia promote repair and regeneration of the peripheral nerve in PNI and may be a new therapeutic drug candidate. Results: The results showed that the amount of secreted sEVs was significantly increased in UC-MSCs compared with control cells after 48 h of culture at 3% oxygen partial pressure in a serum-free culture system. The identified MSC-sEVs could be taken up by SCs in vitro, promoting the growth and migration of SCs. In a spared nerve injury (SNI) mouse model, MSC-sEVs accelerated the recruitment of SCs at the site of PNI and promoted peripheral nerve repair and regeneration. Notably, repair and regeneration in the SNI mouse model were enhanced by treatment with hypoxic cultured UC-MSC-derived sEVs. Discussion: Therefore, we conclude that hypoxic cultured UC-MSC-derived sEVs may be a promising candidate drug for repair and regeneration in PNI.

Functional hair follicle regeneration: an updated review.

The hair follicle (HF) is a highly conserved sensory organ associated with the immune response against pathogens, thermoregulation, sebum production, angiogenesis, neurogenesis and wound healing. Although recent advances in lineage-tracing techniques and the ability to profile gene expression in small populations of cells have increased the understanding of how stem cells operate during hair growth and regeneration, the construction of functional follicles with cycling activity is still a great challenge for the hair research field and for translational and clinical applications. Given that hair formation and cycling rely on tightly coordinated epithelial-mesenchymal interactions, we thus review potential cell sources with HF-inducive capacities and summarize current bioengineering strategies for HF regeneration with functional restoration.

Functional properties and structural changes of rice proteins with anthocyanins complexation.

This study investigated the functional properties and structural changes associated with the complexation of rice protein (RP) with anthocyanins (ACN). Furthermore, fractions (i.e., albumin, globulin, prolamin and glutelin) isolated from RP complexed with anthocyanins were examined. The interactions with ACN altered the structure of RP, leading to an increase in the ß-sheet and spectral shift of the amide Ⅱ band. Additionally, fluorescence spectroscopy suggested that the hydrophobic and hydrogen bonds were the dominant forces in the formation of RP-ACN complexes. It was interesting to find that the RP-ACN particles exhibited the best functional properties at pH 3, likely due to the specific conformational changes upon interaction. In addition, the combination of RP and ACN increased the antioxidant ability of RP. Overall, this research suggested that RP-ACN particles at pH 3 can be designed to form and stabilize mesostructures such as foams and emulsion, which can lead to health benefits.

Sweat gland regeneration: Current strategies and future opportunities.

For patients with extensive skin defects, loss of sweat glands (SwGs) greatly decreases their quality of life. Indeed, difficulties in thermoregulation, ion reabsorption, and maintaining fluid balance might render them susceptible to hyperthermia, heatstroke, or even death. Despite extensive studies on the stem cell biology of the skin in recent years, in-situ regeneration of SwGs with both structural and functional fidelity is still challenging because of the limited regenerative capacity and cell fate control of resident progenitors. To overcome these challenges, one must consider both the intrinsic factors relevant to genetic and epigenetic regulation and cues from the cellular microenvironment. Here, we describe recent progress in molecular biology, developmental pathways, and cellular evolution associated with SwGdevelopment and maturation. This is followed by a summary of the current strategies used for cell-fate modulation, transmembrane drug delivery, and scaffold design associated with SwGregeneration. Finally, we offer perspectives for creating more sophisticated systems to accelerate patients' innate healing capacity and developing engineered skin constructs to treat or replace damaged tissues structurally and functionally.

Chitosan/LiCl composite scaffolds promote skin regeneration in full-thickness loss.

Small molecules loaded into biological materials present a promising strategy for stimulating endogenous repair mechanisms for in situ skin regeneration. Lithium can modulate various biologic processes, promoting proliferation, angiogenesis, and decreasing inflammation. However, its role in skin repair is rarely reported. In this study, we loaded lithium chloride (LiCl) into the chitosan (CHI) hydrogel and develop a sterile and biocompatible sponge scaffold through freeze-drying. In-vitro assessment demonstrated that the CHI-LiCl composite scaffolds (CLiS) possessed favorable cytocompatibility, swelling and biodegradation. We created full-thickness skin wounds in male C57BL/c mice to evaluate the healing capacity of CLiS. Compared with the wounds of control and CHI scaffold (CS) groups, the wounds in the CLiS-treated group showed reduced inflammation, improved angiogenesis, accelerated re-epithelialization, sustained high expression of ß-catenin with a small amount of regenerated hair follicles. Therefore, CLiS may be a promising therapeutic dressing for skin wound repair and regeneration.

Molecular mechanism of myofibroblast formation and strategies for clinical drugs treatments in hypertrophic scars.

Hypertrophic scars (HTS) commonly occurred after burn and trauma. It was characterized by the excessive deposition of extracellular matrix with the inadequate remodeling, which could result in severe physiological and psychological problems. However, the effective available prevention and treatment measures were still limited. The main pathological feature of HTS was the excessive formation of myofibroblasts, and they persist in the repaired tissue. To better understand the mechanics of this process, this review focused on the characteristics and formation of myofibroblasts, the main effector cells in HTS. We summarized the present theories and opinions on myofibroblasts formation from the perspective of related signaling pathways and epigenetic regulation, such as DNA methylation, miRNA/lncRNA/ceRNA action, histone modification, and so forth for a better understanding on the development of HTS. This information might assist in developing effective experimental and clinical treatment strategies. Additionally, we also summarized currently known clinical strategies for HTS treatment, including traditional drugs, molecular medicine, stem cells, and exosomes.

Kirsten Rat Sarcoma Viral Oncogene Homologue (KRAS) Mutations in the Occurrence and Treatment of Pancreatic Cancer.

Pancreatic cancer is a highly malignant tumor with a 5-year survival rate of less than 6%, and incidence increasing year by year globally. Pancreatic cancer has a poor prognosis and a high recurrence rate, almost the same as the death rate. However, the available effective prevention and treatment measures for pancreatic cancer are still limited. The genome variation is one of the main reasons for the development of pancreatic cancer. In recent years, with the development of gene sequencing technology, in-depth research on pancreatic cancer gene mutation presents that a growing number of genetic mutations are confirmed to be in a close relationship with invasion and metastasis of pancreatic cancer. Among them, KRAS mutation is a special one. Therefore, it is particularly important to understand the mechanism of the KRAS mutation in the occurrence and development of pancreatic cancer, and to explore the method of its transformation into clinical tumor molecular targeted treatment sites, to further improve the therapeutic effect on pancreatic cancer. Therefore, to better design chemical drugs, this review based on the biological functions of KRAS, summarized the types of KRAS mutations and their relationship with pancreatic cancer and included the downstream signaling pathway Raf-MEK-ERK, PI3K-AKT, RalGDS-Ral of KRAS and the current medicinal treatment methods for KRAS mutations. Moreover, drug screening and clinical treatment for KRAS mutated cell and animal models of pancreatic cancer are also reviewed along with the prospect of targeted medicinal chemistry therapy for precision treatment of pancreatic cancer in the future.

Concentrated Conditioned Medium-Loaded Silk Nanofiber Hydrogels with Sustained Release of Bioactive Factors To Improve Skin Regeneration.

An injectable hydrogel is a powerful carrier for therapeutic bioactive molecules. Here, an injected concentrated conditioned medium (CCM)-silk nanofiber composite hydrogel was developed to achieve the sustained release of multiple proteins and better wound healing. All the encapsulated proteins showed slow delivery for more than 9 days in vitro. Bioactive molecules such as transforming growth factor-beta1 (TGF-ß1), insulin-like growth factor binding protein-1 (IGFBP-1), and platelet-derived growth factor-AB (PDGF-AB) were successfully released from CCM-loaded hydrogels, and they induced the proliferation and migration of fibroblasts and endothelial cells in a dose- and time-dependent manner. The differentiation of fibroblasts into myofibroblasts was also inhibited, implying less scar formation in vivo. Skin wound regeneration results indicated that the CCM-loaded hydrogel enhanced neovascularization, accelerated wound closure, and promoted hair follicle regeneration. The injectable multiple protein delivery system shows a promising application in skin wound repair.

Arsenic trioxide inhibits the differentiation of fibroblasts to myofibroblasts through nuclear factor erythroid 2-like 2 (NFE2L2) protein and the Smad2/3 pathway.

BACKGROUND: Tissue contraction and the extracellular matrix deposition are part of the pathogenesis of hypertrophic scars. The transcriptional factor NFE2L2 inhibits fibroblast differentiation in idiopathic pulmonary fibrosis and promotes myofibroblast dedifferentiation. Our previous study showed that the transcription factor NFE2L2 was strongly induced on treatment with arsenic trioxide (ATO). OBJECTIVE: The present study sought to investigate the effect of ATO on myofibroblast formation to determine its potential role in hypertrophic scar treatment. METHODS: Small interfering RNA against NFE2L2 was used on treatment with ATO in human skin myofibroblasts. The expression levels of fibrosis markers were assessed by reverse transcription polymerase chain reaction, western blot, and immunofluorescence staining. The transforming growth factor-ß1 (TGF-ß1)/Smad2/3 signaling was detected by western blot. A rabbit ear model was used to evaluate the antifibrotic role of ATO. RESULTS: At the cellular level, ATO abolished fibroblast differentiation in response to TGF-ß1. ATO reduced TGF-ß1-induced reactive oxygen species accumulation through increased expression of the antioxidant gene HO-1 in fibroblasts. In addition, ATO promoted the nuclear translocation of NFE2L2 and inhibited the phosphorylation of Smad2/3. In the rabbit ear model, ATO prevented the progression of hypertrophic scar formation. CONCLUSIONS: This study provides the first evidence implying that ATO inhibits the formation of myofibroblasts in vivo and in vitro and provides a possible treatment for hypertrophic scars.