Needle-Free Injection of Exosomes Derived from Human Dermal Fibroblast Spheroids Ameliorates Skin Photoaging

Stem Cell-Derived Extracellular Vesicle-Bearing Injectable Hydrogel for Collagen Generation in Dermis

Despite the remarkable advances of dermal fillers that reduce wrinkles caused by dermis thickness reduction, they still lack effective hydrogel systems that stimulate collagen generation along with injection convenience. Here, we develop a stem cell-derived extracellular vesicle (EV)-bearing thermosensitive hydrogel (EVTS-Gel) for effective in vivo collagen generation. The TS-Gel undergoes sol-gel transition at 32.6 °C, as demonstrated by the storage and loss moduli crossover. Moreover, the TS-Gel and the EVTS-Gel have comparable rheological properties. Both hydrogels are injected in a sol state; hence, they require lower injection forces than conventional hydrogel-based dermal fillers. When locally administered to mouse skin, the TS-Gel extends the retention time of EVs by 2.23 times. Based on the nature of the controlled EV release, the EVTS-Gel significantly inhibits the dermis thickness reduction caused by aging compared to the bare EV treatment for 24 weeks. After a single treatment, the collagen layer thickness of the EVTS-Gel-treated dermis becomes 2.64-fold thicker than that of the bare EV-treated dermis. Notably, the collagen generation efficacy of the bare EV is poorer than that of the EVTS-Gel of a 10× lesser dose. Overall, the EVTS-Gel shows potential as an antiaging dermal filler for in vivo collagen generation.

High molecular weight hyaluronic acid-liposome delivery system for efficient transdermal treatment of acute and chronic skin photodamage

Photodamage is one of the most common causes of skin injury. High molecular weight hyaluronic acid (HHA) has shown immense potential in the treatment of skin photodamage by virtue of its anti-inflammatory, reparative, and antioxidative properties. However, due to its large molecular structure of HHA, HHA solution could only form a protective film on the skin surface in conventional application, failing to effectively penetrate the skin, which necessitates the development of new delivery strategies. Liposomes, with a structure similar to biological membranes, have garnered extensive attention as transdermal drug delivery carriers because of their advantages in permeability, dermal compatibility, and biosafety. Herein, we have developed a HHA-liposome transdermal system (HHL) by embedding HHA into the liposome structure using reverse evaporation, high-speed homogenization, and micro-jet techniques. The effective penetration and long-term residence of HHA in skin tissue were multidimensionally verified, and the kinetics of HHA in the skin were extensively studied. Moreover, it was demonstrated that HHL significantly strengthened the activity of human keratinocytes and effectively inhibits photo-induced cellular aging in vitro. Furthermore, a murine model of acute skin injury induced by laser ablation was established, where the transdermal system showed significant anti-inflammatory and immunosuppressive properties, promoting skin proliferation and scar repair, thereby demonstrating immense potential in accelerating skin wound healing. Meanwhile, HHL significantly ameliorated skin barrier dysfunction caused by simulated sunlight exposure, inhibited skin erythema, inflammatory responses, and oxidative stress, and promoted collagen expression in a chronic photodamage skin model. Therefore, this transdermal delivery system with biocompatibility represents a promising new strategy for the non-invasive application of HHA in skin photodamage, revealing the significant potential for clinical translation and broad application prospects. STATEMENT OF SIGNIFICANCE: The transdermal system utilizing hyaluronic acid-based liposomes enhances skin permeability and retains high molecular weight hyaluronic acid (HHL). In vitro experiments with human keratinocytes demonstrate significant skin repair effects of HHL and its effective inhibition of cellular aging. In an acute photodamage model, HHL exhibits stronger anti-inflammatory and immunosuppressive properties, promoting skin proliferation and scar repair. In a chronic photodamage model, HHL significantly improves skin barrier dysfunction, reduces oxidative stress induced by simulated sunlight, and enhances collagen expression.

A new subtype of artificial cell-derived vesicles from dental pulp stem cells with the bioequivalence and higher acquisition efficiency compared to extracellular vesicles

Extracellular vesicles (EVs) derived from dental pulp stem cells (DPSC) have been shown an excellent efficacy in a variety of disease models. However, current production methods fail to meet the needs of clinical treatment. In this study, we present an innovative approach to substantially enhance the production of 'Artificial Cell-Derived Vesicles (ACDVs)' by extracting and purifying the contents released by the DPSC lysate, namely intracellular vesicles. Comparative analysis was performed between ACDVs and those obtained through ultracentrifugation. The ACDVs extracted from the cell lysate meet the general standard of EVs and have similar protein secretion profile. The new ACDVs also significantly promoted wound healing, increased or decreased collagen regeneration, and reduced the production of inflammatory factors as the EVs. More importantly, the extraction efficiency is improved by 16 times compared with the EVs extracted using ultracentrifuge method. With its impressive attributes, this new subtype of ACDVs emerge as a prospective candidate for the future clinical applications in regenerative medicine.

Insights into the role of mesenchymal stem cells in cutaneous medical aesthetics: from basics to clinics

With the development of the economy and the increasing prevalence of skin problems, cutaneous medical aesthetics are gaining more and more attention. Skin disorders like poor wound healing, aging, and pigmentation have an impact not only on appearance but also on patients with physical and psychological issues, and even impose a significant financial burden on families and society. However, due to the complexities of its occurrence, present treatment options cannot produce optimal outcomes, indicating a dire need for new and effective treatments. Mesenchymal stem cells (MSCs) and their secretomics treatment is a new regenerative medicine therapy that promotes and regulates endogenous stem cell populations and/or replenishes cell pools to achieve tissue homeostasis and regeneration. It has demonstrated remarkable advantages in several skin-related in vivo and in vitro investigations, aiding in the improvement of skin conditions and the promotion of skin aesthetics. As a result, this review gives a complete description of recent scientific breakthroughs in MSCs for skin aesthetics and the limitations of their clinical applications, aiming to provide new ideas for future research and clinical transformation.

Improving dermal fibroblast-to-epidermis communications and aging wound repair through extracellular vesicle-mediated delivery of Gstm2 mRNA

Skin aging is characterized by the disruption of skin homeostasis and impaired skin injury repair. Treatment of aging skin has long been limited by the unclear intervention targets and delivery techniques. Engineering extracellular vesicles (EVs) as an upgraded version of natural EVs holds great potential in regenerative medicine. In this study, we found that the expression of the critical antioxidant and detoxification gene Gstm2 was significantly reduced in aging skin. Thus, we constructed the skin primary fibroblasts-derived EVs encapsulating Gstm2 mRNA (EVsGstm2), and found that EVsGstm2 could significantly improve skin homeostasis and accelerate wound healing in aged mice. Mechanistically, we found that EVsGstm2 alleviated oxidative stress damage of aging dermal fibroblasts by modulating mitochondrial oxidative phosphorylation, and promoted dermal fibroblasts to regulate skin epidermal cell function by paracrine secretion of Nascent Polypeptide-Associated Complex Alpha subunit (NACA). Furthermore, we confirmed that NACA is a novel skin epidermal cell protective molecule that regulates skin epidermal cell turnover through the ROS-ERK-ETS-Cyclin D pathway. Our findings demonstrate the feasibility and efficacy of EVs-mediated delivery of Gstm2 for aged skin treatment and unveil novel roles of GSTM2 and NACA for improving aging skin.

Extracellular vesicles in nanomedicine and regenerative medicine: A review over the last decade

Small extracellular vesicles (sEVs) are known to be secreted by a vast majority of cells. These sEVs, specifically exosomes, induce specific cell-to-cell interactions and can activate signaling pathways in recipient cells through fusion or interaction. These nanovesicles possess several desirable properties, making them ideal for regenerative medicine and nanomedicine applications. These properties include exceptional stability, biocompatibility, wide biodistribution, and minimal immunogenicity. However, the practical utilization of sEVs, particularly in clinical settings and at a large scale, is hindered by the expensive procedures required for their isolation, limited circulation lifetime, and suboptimal targeting capacity. Despite these challenges, sEVs have demonstrated a remarkable ability to accommodate various cargoes and have found extensive applications in the biomedical sciences. To overcome the limitations of sEVs and broaden their potential applications, researchers should strive to deepen their understanding of current isolation, loading, and characterization techniques. Additionally, acquiring fundamental knowledge about sEVs origins and employing state-of-the-art methodologies in nanomedicine and regenerative medicine can expand the sEVs research scope. This review provides a comprehensive overview of state-of-the-art exosome-based strategies in diverse nanomedicine domains, encompassing cancer therapy, immunotherapy, and biomarker applications. Furthermore, we emphasize the immense potential of exosomes in regenerative medicine.

Novel 3D printed polysaccharide-based materials with prebiotic activity for potential treatment of diaper rash

Diaper rash, mainly occurring as erythema and itching in the diaper area, causes considerable distress to infants and toddlers. Increasing evidence suggests that an unequal distribution of microorganisms on the skin contributes to the development of diaper dermatitis. Probiotic bacteria, like Staphylococcus epidermidis, are crucial for maintaining a healthy balance in the skin's microbiome, among others, through their fermentative metabolites, such as short-chain fatty acids. Using a defined prebiotic as a carbon source (e.g., as part of the diaper formulation) can selectively trigger the fermentation of probiotic bacteria. A proper material choice can reduce diaper rash incidence by diminishing the skin exposure to wetness and faeces. Using 3D printing, we fabricated carbon-rich materials for the top sheet layer of baby diapers that enhance the probiotic activity of S. epidermidis. The developed materials' printability, chemical composition, swelling ability, and degradation rate were analysed. In addition, microbiological tests evaluated their potential as a source of in situ short-chain fatty acid production. Finally, biocompatibility testing with skin cells evaluated their safety for potential use as part of diapers. The results demonstrate a cost-effective approach for producing novel materials that can tailor the ecological balance of the skin microflora and help treat diaper rash.

Selenomethionine in gelatin methacryloyl hydrogels: Modulating ferroptosis to attenuate skin aging

During skin aging, the degeneration of epidermal stem cells (EpiSCs) leads to diminished wound healing capabilities and epidermal disintegration. This study tackles this issue through a comprehensive analysis combining transcriptomics and untargeted metabolomics, revealing age-dependent alterations in the Gpx gene family and arachidonic acid (AA) metabolic networks, resulting in enhanced ferroptosis. Selenomethionine (Se-Met) could enhance GPX4 expression, thereby assisting EpiSCs in countering AA-induced mitochondrial damage and ferroptosis. Additionally, Se-Met demonstrates antioxidative characteristics and extensive ultraviolet absorption. For the sustained and controllable release of Se-Met, it was covalently grafted to UV-responsive GelMA hydrogels via AC-PEG-NHS tethers. The Se-Met@GelMA hydrogel effectively accelerated wound healing in a chronological aging mice model, by inhibiting lipid peroxidation and ferroptosis with augmented GPX4 expression. Moreover, in a photoaging model, this hydrogel significantly mitigated inflammatory responses, extracellular matrix remodeling, and ferroptosis in UV-exposed mice. These characteristics render Se-Met@GelMA hydrogel valuable in practical clinical applications.

A highly bioactive THPC-crosslinked recombinant collagen hydrogel implant for aging skin rejuvenation

Skin aging, a complex physiological progression marked by collagen degradation, poses substantial challenges in dermatology. Recombinant collagen emerges as a potential option for skin revitalization, yet its application is constrained by difficulties in forming hydrogels. We have for the first time developed a highly bioactive Tetrakis(hydroxymethyl) phosphonium chloride (THPC)-crosslinked recombinant collagen hydrogel implant for aging skin rejuvenation. THPC demonstrated superior crosslinking efficiency compared to traditional agents such as EDC/NHS and BDDE, achieving complete recombinant collagen crosslinking at minimal concentrations and effectively inducing hydrogel formation. THPC's four reactive hydroxymethyl groups facilitate robust crosslinking with triple helical recombinant collagen, producing hydrogels with enhanced mechanical strength, excellent injectability, increased stability, and greater durability. Moreover, the hydrogel exhibited remarkable biocompatibility and bioactivity, significantly promoting the proliferation, adhesion, and migration of human foreskin fibroblast-1. In photoaged mice skin models, the THPC-crosslinked collagen hydrogel implant notably improved dermal density, skin elasticity, and reduced transepidermal water loss, creating a conducive environment for fibroblast activity and healthy collagen regeneration. Additionally, it elevated superoxide dismutase (SOD) activity and displayed substantial anti-calcification properties. The THPC-crosslinked recombinant collagen hydrogel implant presents an innovative methodology in combating skin aging, offering significant promise in dermatology and tissue engineering.

The Combined Anti-Aging Effect of Hydrolyzed Collagen Oligopeptides and Exosomes Derived from Human Umbilical Cord Mesenchymal Stem Cells on Human Skin Fibroblasts

Stem cell-derived exosomes (SC-Exos) are used as a source of regenerative medicine, but certain limitations hinder their uses. The effect of hydrolyzed collagen oligopeptides (HCOPs), a functional ingredient of SC-Exos is not widely known to the general public. We herein evaluated the combined anti-aging effects of HCOPs and exosomes derived from human umbilical cord mesenchymal stem cells (HucMSC-Exos) using a senescence model established on human skin fibroblasts (HSFs). This study discovered that cells treated with HucMSC-Exos + HCOPs enhanced their proliferative and migratory capabilities; reduced both reactive oxygen species production and senescence-associated β-galactosidase activity; augmented type I and type III collagen expression; attenuated the expression of matrix-degrading metalloproteinases (MMP-1, MMP-3, and MMP-9), interleukin 1 beta (IL-1β), and tumor necrosis factor-alpha (TNF-α); and decreased the expression of p16, p21, and p53 as compared with the cells treated with HucMSC-Exos or HCOPs alone. These results suggest a possible strategy for enhancing the skin anti-aging ability of HucMSC-Exos with HCOPs.

Opportunities and Perspectives for Three Dimensional Culture of Mesenchymal Stem Cell-Derived Exosomes

Exosomes are nanosized extracellular vesicles (EVs) that participate in intercellular communication through surface proteins and the delivery of internal cargo. The exosomes have gained attention for their potential as disease biomarkers and therapeutic agents. The therapeutic ability of exosomes has been verified by copious previous studies. Effective methods for extensive clinical applications are being researched for exosome-based regenerative therapies, including the application of 3D cultures to enhance exosome production and secretion, which can resolve limited exosome secretion from the parent cells. Cell culture has emerged as a crucial approach for biomedical research because of its many benefits. Both well-established continuous cell lines and primary cell cultures continue to be invaluable for basic research and clinical application. Previous studies have shown that three-dimensional cultured exosomes (3D-Exo) improve therapeutic properties and yields compared with traditional culture systems. Since the majority of studies have focused on exosomes derived from mesenchymal stem cells (MSC-Exo), this review will also concentrate on MSC-Exo. In this review, we will summarize the advantages of 3D-Exo and introduce the 3D culture system and methods of exosome isolation, providing scientific strategies for the diagnosis, treatment, and prognosis of a wide variety of diseases.

Microplastic-induced inhibition of cell adhesion and toxicity evaluation using human dermal fibroblast-derived spheroids

Nanoplastics and microplastics (MPs) can significantly affect marine ecosystems and pose potential risks to human health. Although adverse effects stemming from direct exposure to MPs have been demonstrated at the cellular level in animal models, the potential toxicity of these materials in the human body remains uncertain. In this study, we investigated the three-dimensional (3D) behavior of dermal-derived cells exposed to MPs using artificially manufactured spherical primary polystyrene (PS) particles. To explore these effects, we used cellular spheroids as a 3D cell culture model, examined the size-dependent penetration of PS-MPs, and observed morphological alterations in the spheroids. Furthermore, we assessed changes in physiological activities, including reactive oxygen species, adenosine triphosphate, and lactate dehydrogenase, to elucidate the potential intra- and extracellular toxic reactions to PS-MPs. Additionally, our examination of cell-cell junctions and the extracellular matrix (ECM), along with analysis of the regulators involved in their decreased integrity, revealed negatively influenced changes in expression. This exposure study using spheroid models provides new insights into the potential toxicity of short-term exposure to MPs under conditions that closely resemble in vivo systems.

Micro Trojan horses: Engineering extracellular vesicles crossing biological barriers for drug delivery

The biological barriers of the body, such as the blood-brain, placental, intestinal, skin, and air-blood, protect against invading viruses and bacteria while providing necessary physical support. However, these barriers also hinder the delivery of drugs to target tissues, reducing their therapeutic efficacy. Extracellular vesicles (EVs), nanostructures with a diameter ranging from 30 nm to 10 μm secreted by cells, offer a potential solution to this challenge. These natural vesicles can effectively pass through various biological barriers, facilitating intercellular communication. As a result, artificially engineered EVs that mimic or are superior to the natural ones have emerged as a promising drug delivery vehicle, capable of delivering drugs to almost any body part to treat various diseases. This review first provides an overview of the formation and cross-species uptake of natural EVs from different organisms, including animals, plants, and bacteria. Later, it explores the current clinical applications, perspectives, and challenges associated with using engineered EVs as a drug delivery platform. Finally, it aims to inspire further research to help bioengineered EVs effectively cross biological barriers to treat diseases.

Extracellular vesicles derived from mesenchymal stem cells: the wine in Hebe's hands to treat skin aging

Owing to its constant exposure to the external environment and various stimuli, skin ranks among the organs most vulnerable to manifestations of aging. Preventing and delaying skin aging has become one of the prominent research subjects in recent years. Mesenchymal stem cells (MSCs) are multipotent stem cells derived from mesoderm with high self-renewal ability and multilineage differentiation potential. MSC-derived extracellular vesicles (MSC-EVs) are nanoscale biological vesicles that facilitate intercellular communication and regulate biological behavior. Recent studies have shown that MSC-EVs have potential applications in anti-aging therapy due to their anti-inflammatory, anti-oxidative stress, and wound healing promoting abilities. This review presents the latest progress of MSC-EVs in delaying skin aging. It mainly includes the MSC-EVs promoting the proliferation and migration of keratinocytes and fibroblasts, reducing the expression of matrix metalloproteinases, resisting oxidative stress, and regulating inflammation. We then briefly discuss the recently discovered treatment methods of MSC-EVs in the field of skin anti-aging. Moreover, the advantages and limitations of EV-based treatments are also presented.

Zinc oxide nanoparticles exacerbate skin epithelial cell damage by upregulating pro-inflammatory cytokines and exosome secretion in M1 macrophages following UVB irradiation-induced skin injury

BACKGROUND

Zinc oxide nanoparticles (ZnONPs) are common materials used in skin-related cosmetics and sunscreen products due to their whitening and strong UV light absorption properties. Although the protective effects of ZnONPs against UV light in intact skin have been well demonstrated, the effects of using ZnONPs on damaged or sunburned skin are still unclear. In this study, we aimed to reveal the detailed underlying mechanisms related to keratinocytes and macrophages exposed to UVB and ZnONPs.

RESULTS

We demonstrated that ZnONPs exacerbated mouse skin damage after UVB exposure, followed by increased transepidermal water loss (TEWL) levels, cell death and epithelial thickness. In addition, ZnONPs could penetrate through the damaged epithelium, gain access to the dermis cells, and lead to severe inflammation by activation of M1 macrophage. Mechanistic studies indicated that co-exposure of keratinocytes to UVB and ZnONPs lysosomal impairment and autophagy dysfunction, which increased cell exosome release. However, these exosomes could be taken up by macrophages, which accelerated M1 macrophage polarization. Furthermore, ZnONPs also induced a lasting inflammatory response in M1 macrophages and affected epithelial cell repair by regulating the autophagy-mediated NLRP3 inflammasome and macrophage exosome secretion.

CONCLUSIONS

Our findings propose a new concept for ZnONP-induced skin toxicity mechanisms and the safety issue of ZnONPs application on vulnerable skin. The process involved an interplay of lysosomal impairment, autophagy-mediated NLRP3 inflammasome and macrophage exosome secretion. The current finding is valuable for evaluating the effects of ZnONPs for cosmetics applications.

Understanding exosomes: Part 2-Emerging leaders in regenerative medicine

Exosomes are the smallest subset of extracellular signaling vesicles secreted by most cells with the ability to communicate with other tissues and cell types over long distances. Their use in regenerative medicine has gained tremendous momentum recently due to their ability to be utilized as therapeutic options for a wide array of diseases/conditions. Over 5000 publications are currently being published yearly on this topic, and this number is only expected to dramatically increase as novel therapeutic strategies continue to be developed. Today exosomes have been applied in numerous contexts including neurodegenerative disorders (Alzheimer's disease, central nervous system, depression, multiple sclerosis, Parkinson's disease, post-traumatic stress disorders, traumatic brain injury, peripheral nerve injury), damaged organs (heart, kidney, liver, stroke, myocardial infarctions, myocardial infarctions, ovaries), degenerative processes (atherosclerosis, diabetes, hematology disorders, musculoskeletal degeneration, osteoradionecrosis, respiratory disease), infectious diseases (COVID-19, hepatitis), regenerative procedures (antiaging, bone regeneration, cartilage/joint regeneration, osteoarthritis, cutaneous wounds, dental regeneration, dermatology/skin regeneration, erectile dysfunction, hair regrowth, intervertebral disc repair, spinal cord injury, vascular regeneration), and cancer therapy (breast, colorectal, gastric cancer and osteosarcomas), immune function (allergy, autoimmune disorders, immune regulation, inflammatory diseases, lupus, rheumatoid arthritis). This scoping review is a first of its kind aimed at summarizing the extensive regenerative potential of exosomes over a broad range of diseases and disorders.

Engineered Extracellular Vesicles in Wound Healing: Design, Paradigms, and Clinical Application

The severe quality of life and economic burden imposed by non-healing skin wounds, infection risks, and treatment costs are affecting millions of patients worldwide. To mitigate these challenges, scientists are relentlessly seeking effective treatment measures. In recent years, extracellular vesicles (EVs) have emerged as a promising cell-free therapy strategy, attracting extensive attention from researchers. EVs mediate intercellular communication, possessing excellent biocompatibility and stability. These features make EVs a potential tool for treating a plethora of diseases, including those related to wound repair. However, there is a growing focus on the engineering of EVs to overcome inherent limitations such as low production, relatively fixed content, and targeting capabilities of natural EVs. This engineering could improve both the effectiveness and specificity of EVs in wound repair treatments. In light of this, the present review will introduce the latest progress in the design methods and experimental paradigms of engineered EVs applied in wound repair. Furthermore, it will comprehensively analyze the current clinical research status and prospects of engineered EVs within this field.

Intelligent wound dressing for simultaneous in situ detection and elimination of pathogenic bacteria

Wound infections hinder the healing process and potentially result in life-threatening complications, which urgently require rapid and timely detection and treatment pathogens during the early stages of infection. Here, an intelligent wound dressing was developed to enable in situ detection and elimination of pathogenic bacteria through a combination of point-of-care testing and antibacterial photodynamic therapy technology. The dressing is an injectable hydrogel composed of carboxymethyl chitosan and oxidized sodium alginate, with addition of 4-methylumphulone beta-D-glucoside (MUG) and up-converted nanoparticles coated with titanium dioxide (UCNPs@TiO2). The presence of bacteria can be visually detected by monitoring the blue fluorescence of 4-methylumbellione, generated through the reaction between MUG and the pathogen-associated enzyme. The UCNPs@TiO2 photosensitizers were synthesized and demonstrated high antibacterial activity through the generation of reactive oxygen species when exposed to near-infrared irradiation. Meanwhile, a smartphone-based portable detection system equipped with a self-developed Android app was constructed for in situ detection of pathogens in mere seconds, detecting as few as 103 colony-forming unit. Additionally, the dressing was tested in a rat infected wound model and showed good antibacterial activity and pro-healing ability. These results suggest that the proposed intelligent wound dressing has potential for use in the diagnosis and management of wound infections. STATEMENT OF SIGNIFICANCE: An intelligent wound dressing has been prepared for simultaneous in situ detection and elimination of pathogenic bacteria. The presence of bacteria can be visually detected by tracking the blue fluorescence of the dressing. Moreover, a smartphone-based detection system was constructed to detect and diagnose pathogenic bacteria before reaching the infection limit. Meanwhile, the dressing was able to effectively eliminate key pathogenic bacteria on demand through antibacterial photodynamic therapy under NIR irradiation. The proposed intelligent wound dressing enables timely detection and treatment of infectious pathogens at an early stage, which is beneficial for wound management.

Exosomes in skin photoaging: biological functions and therapeutic opportunity

Exosomes are tiny extracellular vesicles secreted by most cell types, which are filled with proteins, lipids, and nucleic acids (non-coding RNAs, mRNA, DNA), can be released by donor cells to subsequently modulate the function of recipient cells. Skin photoaging is the premature aging of the skin structures over time due to repeated exposure to ultraviolet (UV) which is evidenced by dyspigmentation, telangiectasias, roughness, rhytides, elastosis, and precancerous changes. Exosomes are associated with aging-related processes including, oxidative stress, inflammation, and senescence. Anti-aging features of exosomes have been implicated in various in vitro and pre-clinical studies. Stem cell-derived exosomes can restore skin physiological function and regenerate or rejuvenate damaged skin tissue through various mechanisms such as decreased expression of matrix metalloproteinase (MMP), increased collagen and elastin production, and modulation of intracellular signaling pathways as well as, intercellular communication. All these evidences are promising for the therapeutic potential of exosomes in skin photoaging. This review aims to investigate the molecular mechanisms and the effects of exosomes in photoaging.

Platelet-Derived Apoptotic Vesicles Promote Bone Regeneration via Golgi Phosphoprotein 2 (GOLPH2)-AKT Signaling Axis

Apoptotic vesicles (apoVs) are apoptotic-cell-derived nanosized vesicles that take on dominant roles in regulating bone homeostasis. We have demonstrated that mesenchymal stem cell (MSC)-derived apoVs are promising therapeutic agents for bone regeneration. However, clinical translation of MSC-derived apoVs has been hindered due to cell expansion and nuclear substance. As another appealing source for apoV therapy, blood cells could potentially eliminate these limitations. However, whether blood cells can release apoVs during apoptosis is uncertain, and the detailed characteristics and biological properties of respective apoVs are not elucidated. In this study, we showed that platelets (PLTs) could rapidly release abundant apoVs during apoptosis in a short time. To recognize the different protein expressions between PLT-derived apoVs and PLTs, we established their precise protein landscape. Furthermore, we identified six proteins specifically enriched in PLT-derived apoVs, which could be considered as specific biomarkers. More importantly, PLT-derived apoVs promoted osteogenesis of MSCs and rescued bone loss via Golgi phosphoprotein 2 (GOLPH2)-induced AKT phosphorylation, therefore, leading to the emergence of their potential in bone regeneration. In summary, we comprehensively determined characteristics of PLT-derived apoVs and confirmed their roles in bone metabolism through previously unrecognized GOPLH2-dependent AKT signaling, providing more understanding for exploring apoV-based therapy in bone tissue engineering.

Novel roles of bovine milk-derived exosomes in skin antiaging

BACKGROUND

Exosomes are small vesicles released from cells and are found in various mammalian biological fluids, such as bovine milk, which has been employed in skincare for many years, apart from its dairy applications. In addition, exosomes have been recognized as vehicles for intercellular communication.

AIMS

In this study, we aimed to investigate the novel effects of bovine milk-derived exosomes (MK-Exo) on antiaging in human skin.

METHODS

Initially, MK-Exo were co-cultured with keratinocytes and fibroblasts; subsequent analysis involved qPCR and western blotting to assess induced gene expression. Subsequently, MK-Exo were topically applied to the facial skin of 31 female volunteers twice daily for 28 days. The functions were evaluated after conducting safety assessments in vivo.

RESULTS

Purified MK-Exo demonstrated the ability to be taken up directly by keratinocytes and fibroblasts in vitro, resulting in the upregulation of natural factors associated with skin moisturization, including filaggrin (FLG), aquaporin 3 (AQP3), and CD44 in keratinocytes, as well as hyaluronidase (HAS2) in fibroblasts. Concurrently, MK-Exo promoted fibroblast cell migration and restored the expression of type I and III collagen (Col I and Col III) following exposure to ultraviolet radiation. Furthermore, phototoxicity, photoallergy, repeated skin irritation, skin allergy, and patch tests confirmed the safety of MK-Exo for skin application. Finally, we elucidated the roles of MK-Exo in preserving moisture and reducing wrinkles in humans.

CONCLUSION

Our findings unveil the novel contributions of MK-Exo to human skin aging, presenting a new avenue in the field of skincare.

The frontline of alternatives to animal testing: novel in vitro skin model application in drug development and evaluation

The FDA Modernization Act 2.0 has brought nonclinical drug evaluation into a new era. In vitro models are widely used and play an important role in modern drug development and evaluation, including early candidate drug screening and preclinical drug efficacy and toxicity assessment. Driven by regulatory steering and facilitated by well-defined physiology, novel in vitro skin models are emerging rapidly, becoming the most advanced area in alternative testing research. The revolutionary technologies bring us many in vitro skin models, either laboratory-developed or commercially available, which were all built to emulate the structure of the natural skin to recapitulate the skin's physiological function and particular skin pathology. During the model development, how to achieve balance among complexity, accessibility, capability, and cost-effectiveness remains the core challenge for researchers. This review attempts to introduce the existing in vitro skin models, align them on different dimensions, such as structural complexity, functional maturity, and screening throughput, and provide an update on their current application in various scenarios within the scope of chemical testing and drug development, including testing in genotoxicity, phototoxicity, skin sensitization, corrosion/irritation. Overall, the review will summarize a general strategy for in vitro skin model to enhance future model invention, application, and translation in drug development and evaluation.

Advances in the Applications of Extracellular Vesicle for the Treatment of Skin Photoaging: A Comprehensive Review

Skin photoaging is a complex biological process characterized by the accumulation of oxidative damage and structural changes in the skin, resulting from chronic exposure to ultraviolet (UV) radiation. Despite the growing demand for effective treatments, current therapeutic options for skin photoaging remain limited. However, emerging research has highlighted the potential of extracellular vesicles (EVs), including exosomes, micro-vesicles, apoptotic bodies and liposomes, as promising therapeutic agents in skin rejuvenation. EVs are involved in intercellular communication and can deliver bioactive molecules, including proteins, nucleic acids, and lipids, to recipient cells, thereby influencing various cellular processes. This comprehensive review aims to summarize the current research progress in the application of EVs for the treatment of skin photoaging, including their isolation and characterization methods, roles in skin homeostasis, therapeutic potential and clinical applications for skin photoaging. Additionally, challenges and future directions in EVs-based therapies for skin rejuvenation are discussed.

Strategies for Cartilage Repair in Osteoarthritis Based on Diverse Mesenchymal Stem Cells-Derived Extracellular Vesicles

Osteoarthritis (OA) causes disability and significant economic and social burden. Cartilage injury is one of the main pathological features of OA, and is often manifested by excessive chondrocyte death, inflammatory response, abnormal bone metabolism, imbalance of extracellular matrix (ECM) metabolism, and abnormal vascular or nerve growth. Regrettably, due to the avascular nature of cartilage, its capacity to repair is notably limited. Mesenchymal stem cells-derived extracellular vesicles (MSCs-EVs) play a pivotal role in intercellular communication, presenting promising potential not only as early diagnostic biomarkers in OA but also as efficacious therapeutic strategy. MSCs-EVs were confirmed to play a therapeutic role in the pathological process of cartilage injury mentioned above. This paper comprehensively provides the functions and mechanisms of MSCs-EVs in cartilage repair.

Mesenchymal stem cell-derived exosomes and skin photoaging: From basic research to practical application

BACKGROUND

Skin photoaging is a condition caused by long-term exposure to ultraviolet irradiation, resulting in a variety of changes in the skin, such as capillary dilation, increased or absent pigmentation, dryness, sagging, and wrinkles. Stem cells possess a remarkable antioxidant capacity and the ability to proliferate, differentiate, and migrate, and their main mode of action is through paracrine secretion, with exosomes being the primary form of secretion. Stem cell-derived exosomes contain a variety of growth factors and cytokines and may have great potential to promote skin repair and delay skin ageing.

METHODS

This review focuses on the mechanisms of UV-induced skin photoaging, the research progress of stem cell exosomes against skin photoaging, emerging application approaches and limitations in the application of exosome therapy.

RESULT

Exosomes derived from various stem cells have the potential to prevent skin photoaging.

CONCLUSION

The combination with novel materials may be a key step for their practical application, which could be an important direction for future basic research and practical applications.

Single-Walled Carbon Nanotube-Guided Topical Skin Delivery of Tyrosinase to Prevent Photoinduced Damage

When the skin is exposed to ultraviolet radiation (UV), it leads to the degradation of the extracellular matrix (ECM) and results in inflammation. Subsequently, melanocytes are triggered to induce tyrosinase-mediated melanin synthesis, protecting the skin. Here, we introduce a proactive approach to protect the skin from photodamage via the topical delivery of Streptomyces avermitilis-derived tyrosinase (SaTy) using single-walled carbon nanotube (SWNT). Utilizing a reverse electrodialysis (RED) battery, we facilitated the delivery of SaTy-SWNT complexes up to depths of approximately 300 μm, as analyzed by using confocal Raman microscopy. When applied to ex vivo porcine skin and in vivo albino mouse skin, SaTy-SWNT synthesized melanin, resulting in 4-fold greater UV/vis absorption at 475 nm than in mice without SaTy-SWNT. The synthesized melanin efficiently absorbed UV light and alleviated skin inflammation. In addition, the densification of dermal collagen, achieved through SaTy-mediated cross-linking, reduced photoinduced wrinkles by 66.3% in the affected area. Our findings suggest that SWNT-mediated topical protein delivery holds promise in tissue engineering applications.

Exosomes as cutting-edge therapeutics in various biomedical applications: An update on engineering, delivery, and preclinical studies

Exosomes are cell-derived nanovesicles, circulating in different body fluids, and acting as an intercellular mechanism. They can be purified from culture media of different cell types and carry an enriched content of various protein and nucleic acid molecules originating from their parental cells. It was indicated that the exosomal cargo can mediate immune responses via many signaling pathways. Over recent years, the therapeutic effects of various exosome types were broadly investigated in many preclinical studies. Herein, we present an update on recent preclinical studies on exosomes as therapeutic and/or delivery agents for various applications. The exosome origin, structural modifications, natural or loaded active ingredients, size, and research outcomes were summarized for various diseases. Overall, the present article provides an overview of the latest exosome research interests and developments to clear the way for the clinical study design and application.

Research on Circular RNA Expression Profiles in the Photoaging Mouse Model

Background

Nude mouse has been widely used to study photoaging induced by long-term chronic UV exposure. Circular RNAs (circRNAs) have been previously identified in several diseases. However, the roles of circRNAs in photoaging and potential regulatory mechanisms remain unclear.

Objectives

To identify specific circRNAs differentially expressed in photoaged skin and investigate their potential role in aging.

Materials and Methods

In this study, we screened out the microarray data to profile the expression of circRNAs. The circRNAs were analyzed by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) biological pathway.

Results

36 circRNAs were identified to be differentially expressed between the UV group and control group (fold change > 1.5; P < 0.05), including 6 upregulated and 30 downregulated circRNAs. GO and KEGG biological pathway analyses indicated that the changes in circRNAs were associated with cancer, inflammation, oxidative stress, and metabolism.

Conclusions

This present study revealed a circRNAs expression profiling in vivo. These findings not only provide a new possibility to prevent the occurrence of photoaging but also have therapeutic values for photoaging and associated skin diseases.

A review of exosomes and their application in cutaneous medical aesthetics

BACKGROUND

Exosomes have gained recent popularity in aesthetic medicine; however, there is still a dearth of understanding on the etiology of exosomes, their physiologic function, and regenerative capabilities.

OBJECTIVE

The purpose of this article is to summarize some of the physiologic functions of exosomes, their mechanistic role, and current commercial landscape in regenerative aesthetics.

METHODS

A Medline search was conducted with the keywords, exosomes, extracellular vesicles, stem cells, skin rejuvenation, and cutaneous aesthetics. MeSH term "exosomes" filtered by relevant subheadings was also utilized. Pertinent original articles encompassing animal studies, cell studies, and human studies were included. We restricted to articles published in the last 10 years.

RESULTS

Pre-clinical studies have demonstrated the therapeutic capabilities of exosomes in wound healing, scar modulation, alopecia, and skin rejuvenation. Exosomes primarily exert their effects in a paracrine function and modulate the interactions between keratinocytes and other cells of the skin. Exogenous exosomes can be utilized in a variety of settings to bring about desired aesthetic outcomes and to date, has only been approved for topical administration.

CONCLUSION

The safety, efficacy, potency, and dosages of exosomes remains to be determined via robust human clinical trials. Isolation and purification techniques have yet to be standardized, and this would be required for regulatory approval of all delivery modes. Overall, exosomes deliver yet another therapeutic option in regenerative aesthetics.

mRNA nanodelivery systems: targeting strategies and administration routes

With the great success of coronavirus disease (COVID-19) messenger ribonucleic acid (mRNA) vaccines, mRNA therapeutics have gained significant momentum for the prevention and treatment of various refractory diseases. To function efficiently in vivo and overcome clinical limitations, mRNA demands safe and stable vectors and a reasonable administration route, bypassing multiple biological barriers and achieving organ-specific targeted delivery of mRNA. Nanoparticle (NP)-based delivery systems representing leading vector approaches ensure the successful intracellular delivery of mRNA to the target organ. In this review, chemical modifications of mRNA and various types of advanced mRNA NPs, including lipid NPs and polymers are summarized. The importance of passive targeting, especially endogenous targeting, and active targeting in mRNA nano-delivery is emphasized, and different cellular endocytic mechanisms are discussed. Most importantly, based on the above content and the physiological structure characteristics of various organs in vivo, the design strategies of mRNA NPs targeting different organs and cells are classified and discussed. Furthermore, the influence of administration routes on targeting design is highlighted. Finally, an outlook on the remaining challenges and future development toward mRNA targeted therapies and precision medicine is provided.

Recent advances in exosomal non-coding RNA-based therapeutic approaches for photoaging

BACKGROUND

Photoaging is a degenerative biological process that affects the quality of life. It is caused by environmental factors including ultraviolet radiation (UVR), deep skin burns, smoking, active oxygen, chemical substances, and trauma. Among them, UVR plays a vital role in the aging process.

AIM

With the continuous development of modern medicine, clinical researchers have investigated novel approaches to treat aging. In particular, mesenchymal stem cells (MSCs), non-coding RNAs are involved in various physiological processes have broad clinical application as they have the advantages of convenient samples, abundant sources, and avoidable ethical issues.

METHODS

This article reviews research progress on five types of stem cell, exosomes, non-coding RNA in the context of photoaging treatment: adipose-derived stem cell, human umbilical cord MSCs, epidermal progenitor cells, keratinocyte stem cells, and hair follicle stem cells (HFSCs). It also includes stem cell related exosomes and their non-coding RNA research.

RESULTS

The results have clinical guiding significance for prevention and control of the onset and development of photoaging. It is found that stem cells secrete cytokines, cell growth factors, non-coding RNA, exosomes and proteins to repair aging skin tissues and achieve skin rejuvenation. In particular, stem cell exosomes and non-coding RNA are found to have significant research potential, as they possess the benefits of their source cells without the disadvantages which include immune rejection and granuloma formation.

[Physicochemical properties of a novel chiral self-assembling peptide R-LIFE-1 and its controlled release to exosomes]

This research aims to investigate the encapsulation and controlled release effect of the newly developed self-assembling peptide R-LIFE-1 on exosomes. The gelling ability and morphological structure of the chiral self-assembling peptide (CSAP) hydrogel were examined using advanced imaging techniques, including atomic force microscopy, transmission electron microscopy, and cryo-scanning electron microscopy. The biocompatibility of the CSAP hydrogel was assessed through optical microscopy and fluorescent staining. Exosomes were isolated via ultrafiltration, and their quality was evaluated using Western blot analysis, nanoparticle tracking analysis, and transmission electron microscopy. The controlled release effect of the CSAP hydrogel on exosomes was quantitatively analyzed using laser confocal microscopy and a BCA assay kit. The results revealed that the self-assembling peptide R-LIFE-1 exhibited spontaneous assembly in the presence of various ions, leading to the formation of nanofibers. These nanofibers were cross-linked, giving rise to a robust nanofiber network structure, which further underwent cross-linking to generate a laminated membrane structure. The nanofibers possessed a large surface area, allowing them to encapsulate a substantial number of water molecules, thereby forming a hydrogel material with high water content. This hydrogel served as a stable spatial scaffold and loading matrix for the three-dimensional culture of cells, as well as the encapsulation and controlled release of exosomes. Importantly, R-LIFE-1 demonstrated excellent biocompatibility, preserving the growth of cells and the biological activity of exosomes. It rapidly formed a three-dimensional network scaffold, enabling the stable loading of cells and exosomes, while exhibiting favorable biocompatibility and reduced cytotoxicity. In conclusion, the findings of this study support the notion that R-LIFE-1 holds significant promise as an ideal tissue engineering material for tissue repair applications.

Mesenchymal stem cell-derived extracellular vesicles in skin wound healing: roles, opportunities and challenges

Skin wounds are characterized by injury to the skin due to trauma, tearing, cuts, or contusions. As such injuries are common to all human groups, they may at times represent a serious socioeconomic burden. Currently, increasing numbers of studies have focused on the role of mesenchymal stem cell (MSC)-derived extracellular vesicles (EVs) in skin wound repair. As a cell-free therapy, MSC-derived EVs have shown significant application potential in the field of wound repair as a more stable and safer option than conventional cell therapy. Treatment based on MSC-derived EVs can significantly promote the repair of damaged substructures, including the regeneration of vessels, nerves, and hair follicles. In addition, MSC-derived EVs can inhibit scar formation by affecting angiogenesis-related and antifibrotic pathways in promoting macrophage polarization, wound angiogenesis, cell proliferation, and cell migration, and by inhibiting excessive extracellular matrix production. Additionally, these structures can serve as a scaffold for components used in wound repair, and they can be developed into bioengineered EVs to support trauma repair. Through the formulation of standardized culture, isolation, purification, and drug delivery strategies, exploration of the detailed mechanism of EVs will allow them to be used as clinical treatments for wound repair. In conclusion, MSC-derived EVs-based therapies have important application prospects in wound repair. Here we provide a comprehensive overview of their current status, application potential, and associated drawbacks.

Various Three-Dimensional Culture Methods and Cell Types for Exosome Production

Cell-based therapies have been used as promising treatments for several untreatable diseases. However, cell-based therapies have side effects such as tumorigenesis and immune responses. To overcome these side effects, therapeutic effects of exosomes have been researched as replacements for cell-based therapies. In addition, exosomes reduced the risk that can be induced by cell-based therapies. Exosomes contain biomolecules such as proteins, lipids, and nucleic acids that play an essential role in cell-cell and cell-matrix interactions during biological processes. Since the introduction of exosomes, those have been proven perpetually as one of the most effective and therapeutic methods for incurable diseases. Much research has been conducted to enhance the properties of exosomes, including immune regulation, tissue repair, and regeneration. However, yield rate of exosomes is the critical obstacle that should be overcome for practical cell-free therapy. Three-dimensional (3D) culture methods are introduced as a breakthrough to get higher production yields of exosomes. For example, hanging drop and microwell were well known 3D culture methods and easy to use without invasiveness. However, these methods have limitation in mass production of exosomes. Therefore, a scaffold, spinner flask, and fiber bioreactor were introduced for mass production of exosomes isolated from various cell types. Furthermore, exosomes treatments derived from 3D cultured cells showed enhanced cell proliferation, angiogenesis, and immunosuppressive properties. This review provides therapeutic applications of exosomes using 3D culture methods.

Peelable Microneedle Patches Deliver Fibroblast Growth Factors to Repair Skin Photoaging Damage

Rationale: UV light deeply penetrates the dermis, leading to inflammation and cell death with prolonged exposure. This is a major contributor to skin photoaging. In the pharmaceutical field, fibroblast growth factors (FGFs) have gained popularity for enhancing skin quality as they facilitate tissue remodeling and re-epithelization. Nonetheless, their effectiveness is significantly hindered by limited absorption. Methods: We have successfully created a dissolving microneedle (MN) patch that contains hyaluronic acid (HA) loaded with FGF-2 and FGF-21. This patch aims to improve the therapeutic efficiency of these growth factors while providing a simple administration method. We determined the performance of this patch in an animal model of skin photoaging. Results: The FGF-2/FGF-21-loaded MN (FGF-2/FGF-21 MN) patch demonstrated a consistent structure and suitable mechanical properties, allowing for easy insertion and penetration into mouse skin. Within 10 minutes of application, the patch released approximately 38.50 ± 13.38% of the loaded drug. Notably, the FGF-2/FGF-21 MNs exhibited significant improvements in UV-induced acute skin inflammation and reduced mouse skin wrinkles within a span of two weeks. Furthermore, the positive effects continued to enhance over a four-week treatment period. Conclusion: The proposed HA-based peelable MN patch provides an efficient approach for transdermal drug delivery, providing a promising method for improved therapeutic outcomes.

The Potential Role of Exosomes in Aesthetic Plastic Surgery: A Review of Current Literature

Despite an increasing surge of exosome use throughout the aesthetic arena, a paucity of published exosome-based literature exists. Exosomes are membrane-bound extracellular vesicles derived from various cell types, exerting effects via intercellular communication and regulation of several signaling pathways. The purpose of this review was to summarize published articles elucidating mechanisms and potential applications, report available products and clinical techniques, and prompt further investigation of this emerging treatment within the plastic surgery community.

Methods

A literature review was performed using PubMed with keywords exosomes, secretomes, extracellular vesicles, plastic surgery, skin rejuvenation, scar revision, hair growth, body contouring, and breast augmentation. Publications from 2010 to 2021 were analyzed for relevance and level of evidence. A Google search identified exosome distributors, where manufacturing/procurement details, price, efficacy, and clinical indications for use were obtained by direct contact and summarized in table format.

Results

Exosomes are currently derived from bone marrow, placental, adipose, and umbilical cord tissue. Laboratory-based exosome studies demonstrate enhanced outcomes in skin rejuvenation, scar revision, hair restoration, and fat graft survival on the macro and micro levels. Clinical studies are limited to anecdotal results. Prices vary considerably from $60 to nearly $5000 based on company, source tissue, and exosome concentration. No exosome-based products are currently Food and Drug Administration-approved.

Conclusions

Administered alone or as an adjunct, current reports show promise in several areas of aesthetic plastic surgery. However, ongoing investigation is warranted to further delineate concentration, application, safety profile, and overall outcome efficacy.

Tailored Apoptotic Vesicle Delivery Platform for Inflammatory Regulation and Tissue Repair to Ameliorate Ischemic Stroke

Apoptotic vesicles (ApoVs) hold great promise for inflammatory regulation and tissue repair. However, little effort has been dedicated to developing ApoV-based drug delivery platforms, while the insufficient targeting capability of ApoVs also limits their clinical applications. This work presents a platform architecture that integrates apoptosis induction, drug loading, and functionalized proteome regulation, followed by targeting modification, enabling the creation of an apoptotic vesicle delivery system to treat ischemic stroke. Briefly, α-mangostin (α-M) was utilized to induce mesenchymal stem cell (MSC) apoptosis while being loaded onto MSC-derived ApoVs as an anti-oxidant and anti-inflammatory agent for cerebral ischemia/reperfusion injury. Matrix metalloproteinase activatable cell-penetrating peptide (MAP), a microenvironment-responsive targeting peptide, was modified on the surface of ApoVs to obtain the MAP-functionalized α-M-loaded ApoVs. Such engineered ApoVs targeted the injured ischemic brain after systemic injection and achieved an enhanced neuroprotective activity due to the synergistic effect of ApoVs and α-M. The internal protein payloads of ApoVs, upon α-M activation, were found engaged in regulating immunological response, angiogenesis, and cell proliferation, all of which contributed to the therapeutic effects of ApoVs. The findings provide a universal framework for creating ApoV-based therapeutic drug delivery systems for the amelioration of inflammatory diseases and demonstrate the potential of MSC-derived ApoVs to treat neural injury.

LncRNA PVT1 delays skin photoaging by sequestering miR-551b-3p to release AQP3 expression via ceRNA mechanism

Understanding human skin photoaging requires in-depth knowledge of the molecular and functional mechanisms. Human dermal fibroblasts (HDFs) gradually lose their ability to produce collagen and renew intercellular matrix with aging. Therefore, our study aims to reveal the mechanistic actions of a novel ceRNA network in the skin photoaging by regulating HDF activities. Photoaging-related genes were obtained in silico, followed by GO and KEGG enrichment analyses. Differentially expressed lncRNAs and miRNAs were screened from the GEO database to construct the ceRNA co-expression network. In skin photoaging samples, PVT1 and AQP3 were poorly expressed, while miR-551b-3p was highly expressed. The relationships among the lncRNA, miRNA and mRNA were explored through the ENCORI database and dual luciferase reporter assay. Mechanistically, PVT1 could sequester miR-551b-3p to upregulate the expression of AQP3, which further inactivated the ERK/p38 MAPK signaling pathway. HDFs were selected to construct an in vitro cell skin photoaging model, where the senescence, cell cycle distribution and viability of young and senescent HDFs were detected by SA-β-gal staining, flow cytometry and CCK-8 assay. In vitro cell experiments confirmed that overexpression of PVT1 or AQP3 enhanced viability of young and senescent HDFs and inhibited HDF senescence, while miR-551b-3p upregulation counteracted the effect of PVT1. In conclusion, PVT1-driven suppression of miR-551b-3p induces AQP3 expression to inactivate the ERK/p38 MAPK signaling pathway, thereby inhibiting HDF senescence and ultimately delaying the skin photoaging.

Engineering exosome-based biomimetic nanovehicles for wound healing

Complexity and difficulties in wound management are pressing concerns that affect patients' quality of life and may result in tissue infection, necrosis, and loss of local and systemic functions. Hence, novel approaches to accelerate wound healing are being actively explored over the last decade. Exosomes as important mediators of intercellular communications are promising natural nanocarriers due to their biocompatibility, low immunogenicity, drug loading and targeting capacities, and innate stability. More importantly, exosomes are developed as a versatile pharmaceutical engineering platform for wound repair. This review provides an overview of the biological and physiological functions of exosomes derived from a variety of biological origins during wound healing phases, strategies for exosomal engineering, and therapeutic applications in skin regeneration.

Production and Utility of Extracellular Vesicles with 3D Culture Methods

In recent years, extracellular vesicles (EVs) have emerged as promising biomarkers, cell-free therapeutic agents, and drug delivery carriers. Despite their great clinical potential, poor yield and unscalable production of EVs remain significant challenges. When using 3D culture methods, such as scaffolds and bioreactors, large numbers of cells can be expanded and the cell environment can be manipulated to control the cell phenotype. This has been employed to successfully increase the production of EVs as well as to enhance their therapeutic effects. The physiological relevance of 3D cultures, such as spheroids, has also provided a strategy for understanding the role of EVs in the pathogenesis of several diseases and to evaluate their role as tools to deliver drugs. Additionally, 3D culture methods can encapsulate EVs to achieve more sustained therapeutic effects as well as prevent premature clearance of EVs to enable more localised delivery and concentrated exosome dosage. This review highlights the opportunities and drawbacks of different 3D culture methods and their use in EV research.

Exosomes: the latest in regenerative aesthetics

Regenerative aesthetics is a burgeoning field for skin rejuvenation and skin health restoration. Exosomes, or extracellular vesicles, represent a new and minimally invasive addition to the regenerative aesthetic toolbox. These nano-sized vesicles contain bioactive cargo with crucial roles in intercellular communication. Exosome technology, while still in its infancy, is now leveraged in regenerative aesthetic medicine due to its multifaceted role in targeting root causes of skin aging and improving overall tissue homeostasis. The main considerations for practice utilization include variation in exosome purification, isolation, storage, scalability and reproducibility. This review aims at highlighting the current and emerging landscape of exosomes in aesthetic medicine including skin rejuvenation and hair restoration.

Genetically modified cell spheroids for tissue engineering and regenerative medicine

Cell spheroids offer cell-to-cell interactions and show advantages in survival rate and paracrine effect to solve clinical and biomedical inquiries ranging from tissue engineering and regenerative medicine to disease pathophysiology. Therefore, cell spheroids are ideal vehicles for gene delivery. Genetically modified spheroids can enhance specific gene expression to promote tissue regeneration. Gene deliveries to cell spheroids are via viral vectors or non-viral vectors. Some new technologies like CRISPR/Cas9 also have been used in genetically modified methods to deliver exogenous gene to the host chromosome. It has been shown that genetically modified cell spheroids had the potential to differentiate into bone, cartilage, vascular, nerve, cardiomyocytes, skin, and skeletal muscle as well as organs like the liver to replace the diseased organ in the animal and pre-clinical trials. This article reviews the recent articles about genetically modified spheroid cells and explains the fabrication, applications, development timeline, limitations, and future directions of genetically modified cell spheroid.

A highly efficient needle-free-injection delivery system for mRNA-LNP vaccination against SARS-CoV-2

Despite the various vaccines that have been developed to combat the coronavirus disease 2019 (COVID-19) pandemic, the persistent and unpredictable mutations of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) require innovative and unremitting solutions to cope with the resultant immune evasion and establish a sustainable immune barrier. Here we introduce a vaccine-delivery system with a combination of a needle-free injection (NFI) device and a SARS-CoV-2-Spike-specific mRNA-Lipid Nanoparticle (LNP) vaccine. The benefits are duller pain and a significant increase of immunogenicity compared to the canonical needle injection (NI). From physicochemical and bioactivity analyses, the structure of the mRNA-LNP maintains stability upon NFI, contradictory to the belief that LNPs are inclined towards destruction under the high-pressure conditions of NFI. Moreover, mRNA-LNP vaccine delivered by NFI induces significantly more binding and neutralizing antibodies against SARS-CoV-2 variants than the same vaccine delivered by NI. Heterogeneous vaccination of BA.5-LNP vaccine with NFI enhanced the generation of neutralizing antibodies against Omicron BA.5 variants in rabbits previously vaccinated with non-BA.5-specific mRNA-LNP or other COVID-19 vaccines. NFI parameters can be adjusted to deliver mRNA-LNP subcutaneously or intramuscularly. Taken together, our results suggest that NFI-based mRNA-LNP vaccination is an effective substitute for the traditional NI-based mRNA-LNP vaccination.

Stem cell-derived exosomes in the treatment of melasma and its percutaneous penetration

BACKGROUND AND OBJECTIVES

Melasma is a refractory skin disease due to its complex pathogenesis and difficult treatment. Studies have found that human umbilical cord mesenchymal stem cell-derived exosomes (hUCMSC-Exos) could serve as a novel cell-free therapeutic strategy in regenerative and esthetic medicine. It could potentially treat melasma, but the skin barrier is a challenge. In this study, we aim to explore the safety and efficacy of hUCMSC-Exos in the treatment of melasma and the means to promote its percutaneous penetration.

MATERIALS AND METHODS

In the animal study about the effect of penetration, percutaneous penetration of PKH67-labeled hUCMSC-Exos was studied under microneedles, 1565 nm nonablative fractional laser (NAFL), and a plasma named Peninsula Blue Aurora Shumin Master (PBASM) treatments, observed by confocal laser scanning microscopy. In the clinical application study, 60 patients with melasma treated in our department were divided into four groups. NAFL combined with normal saline treatment was used for Group A. Microneedles, NAFL, and PBASM combined with hUCMSC-Exos treatments were used for Groups B, C, and D, respectively. Each patient received four treatments at 1-month intervals. Assessments were done using the degree of pain posttreatment, melasma area and severity score, improvement rate, physician global assessment score, satisfaction, and complications.

RESULTS

In the animal study about the effect of penetration, hUCMSC-Exos can penetrate the deep dermis under microneedles, NAFL, and PBASM treatments. In the clinical application study, compared with Group A, Groups B, C, and D showed significantly improved therapeutic effect and patient satisfaction (p < 0.05), and there was no significant difference among Groups B, C, and D.(p > 0.05). Patients in Group B reported higher pain levels than those in the other three groups (p < 0.05); the treatment experience of patients in Group D was better.

CONCLUSION

hUCMSC-Exos can improve the symptoms of melasma safely and effectively. Compared with microneedles, NAFL and PBASM can also achieve a good effect toward promoting penetration. These findings are worthy of exploration and clinical application.

Fetal Fibroblast Transplantation via Ablative Fractional Laser Irradiation Reduces Scarring

Scar treatments include fractional laser treatment, cell transplantation, surgery, skin needling, and dermal fillers. Fractional laser treatments are used to reduce scarring and blurring. Cell transplantation is promising, with mature fibroblasts and adipose-derived stem cells being used clinically, while embryonic fibroblasts are used experimentally. Herein, we developed a combination of ablative CO₂ (carbon dioxide) fractional laser and cell transplantation for the treatment of scars. Eight-week-old male C57Bl/6 mice were used to create a full-layer skin defect in the back skin and create scars. The scar was then irradiated using a CO₂ fractional laser. The cells were then transplanted onto the scar surface and sealed with a film agent. The transplanted cells were GFP-positive murine fetal fibroblasts (FB), fetal fibroblasts with a long-term sphere-forming culture (LS), and fetal skin with a short-term sphere-forming culture (SS). After transplantation, green fluorescent protein (GFP)-positive cells were scattered in the dermal papillary layer and subcutis in all the groups. LS significantly reduced the degree of scarring, which was closest to normal skin. In conclusion, the combination of ablative fractional laser irradiation and fetal fibroblast transplantation allowed us to develop new methods for scar treatment.

Intradermally delivered mRNA-encapsulating extracellular vesicles for collagen-replacement therapy

The success of messenger RNA therapeutics largely depends on the availability of delivery systems that enable the safe, effective and stable translation of genetic material into functional proteins. Here we show that extracellular vesicles (EVs) produced via cellular nanoporation from human dermal fibroblasts, and encapsulating mRNA encoding for extracellular-matrix α1 type-I collagen (COL1A1) induced the formation of collagen-protein grafts and reduced wrinkle formation in the collagen-depleted dermal tissue of mice with photoaged skin. We also show that the intradermal delivery of the mRNA-loaded EVs via a microneedle array led to the prolonged and more uniform synthesis and replacement of collagen in the dermis of the animals. The intradermal delivery of EV-based COL1A1 mRNA may make for an effective protein-replacement therapy for the treatment of photoaged skin.

The therapeutic and commercial landscape of stem cell vesicles in regenerative dermatology

Extracellular vesicles (EVs) are lipid enveloped nanoparticles that are naturally produced by cells and function in the intercellular transfer of biological material such as proteins, RNAs and metabolites. They have been shown to act in an autocrine and paracrine manner to alter the functions of local and distant recipient cells, with a growing body of evidence highlighting their wide-ranging functions in regenerative processes such as stem cell maintenance, tissue repair and immune modulation. EVs offer several potential advantages over stem cell therapies such as improved safety profiles, scalability, and enhanced storage and quality control of the final product. In fact, many of the pro-regenerative outcomes of stem cell therapies have been attributed to the release of mesenchymal stem cell-derived EVs (MSC-EVs) and their potent effects on extracellular matrix turnover, local cell recruitment, proliferation and angiogenesis is now well described. These positive outcomes have led to clinical trials assessing the safety of MSC-EVs for applications in wound healing and the treatment of cutaneous ulcers, as well as the emergence of multiple commercial MSC-EV sources marketed for topical application in cosmetic medicine. However, regenerative EV therapeutics remain in their infancy and pertinent questions regarding product standardisation, potency and the regulatory landscape surrounding the development of these promising nano-therapeutics must be addressed to ensure safe and effective clinical adoption. In this article we provide an overview of the emerging landscape of MSC-EVs in regenerative dermatology and cosmetic science, highlighting the underlying biological mechanisms pertinent to their application and providing a perspective on current safety considerations, regulation and future directions in the field.

Continuous nutrient supply culture strategy controls multivesicular endosomes pathway and anti-photo-aging miRNA cargo loading of extracellular vesicles

Extracellular vesicle (EV) therapy recently had shown significant efficacy in various diseases. Serum starvation culture (SC) is one of the most widely used methods for collecting EVs. However, SC may cause inadvertent effects and eventually dampen the therapeutic potential of EVs. Therefore, we developed a novel method for EV collection, continuous nutrient supply culture (CC), which can provide an optimal condition for mesenchymal stem cells (MSCs) by continuously supplying essential nutrients to MSCs. By comparing with SC strategy, we revealed that CC could maintain CC-MSCs in a normal autophagy and apoptotic state, which reduced the shunting of EV precursors in cells and useless information material carried by EVs. In CC-MSCs, the expression levels of endosomal sorting complexes required for transport (ESCRT) and targeting GTPase27 (Rab27) were upregulated compared to those in SC-MSCs. Besides, we analyzed the membrane transport efficiency of EV formation, which demonstrated the CC strategy could promote the formation of EV precursors and the release of EVs. In addition, miRNA analysis revealed that CC-EVs were enriched with anti-chronic inflammatory factors, which could inhibit the nuclear factor kappa-B (NF-κB) pathway, mitigate chronic inflammation, and effectively repair skin photo-aging damage.