Keratinocyte and Fibroblast Wound Healing In Vitro Is Repressed by Non-Optimal Conditions but the Reparative Potential Can Be Improved by Water-Filtered Infrared A

Ligilactobacillus salivarius Lac45 inhibits MRSA and suppresses inflammation in human keratinocyte

Dysbiosis, an imbalance in skin microflora, is a key contributor to inflammatory skin conditions, including atopic dermatitis (AD), seborrheic dermatitis (SD), and psoriasis. In AD, Staphylococcus aureus colonization of skin lesions is prevalent approximately 70% of cases, with disease severity positively correlating with bacterial presence. Moreover, methicillin-resistant Staphylococcus aureus (MRSA) is found in 10-30% of AD skin lesions, highlighting the need for novel therapeutic strategies that target both microbial imbalance and inflammation. This study evaluates Ligilactobacillus salivarius Lac45 (LS-Lac45), a breast milk-derived bacterial strain, for its antimicrobial and anti-inflammatory potential in dermatology. We assessed its antimicrobial activity against MRSA using an agar disk-diffusion assay and its anti-inflammatory effects in a peptidoglycan (PGN)-induced inflammation model in HaCaT keratinocytes. To elucidate its mechanisms of action, mass spectrometry was used to analyze protein expression changes in LS-Lac45-treated keratinocytes. Our results demonstrate that live LS-Lac45 effectively inhibits MRSA growth. Additionally, heat-killed LS-Lac45 significantly reduces PGN-induced production of pro-inflammatory cytokines IL-6, IL-8, and TNF-α. Proteomic analysis further identifies LS-Lac45-mediated modulation of immune-related proteins, including heat shock protein 60, metallothionein 2A, and antioxidant-1, suggesting a role in inflammatory regulation. These findings highlight LS-Lac45 as a candidate for managing MRSA-associated inflammatory skin conditions, particularly AD. While this study provides key insights into its antimicrobial and immunomodulatory properties, further research is needed to evaluate its probiotic characteristics and clinical applicability in dermatology.

Cannabidiol-Loaded Lipid Nanoparticles Incorporated in Polyvinyl Alcohol and Sodium Alginate Hydrogel Scaffold for Enhancing Cell Migration and Accelerating Wound Healing

Chronic wounds represent a persistent clinical challenge due to prolonged inflammation and impaired tissue repair mechanisms. Cannabidiol (CBD), recognized for its anti-inflammatory and pro-healing properties, shows therapeutic promise in wound care. However, its delivery via lipid nanoparticles (LNPs) remains challenging due to CBD's inherent instability and low bioavailability. This study developed and characterized a novel hydrogel scaffold composed of CBD-loaded LNPs (CBD/LNPs) integrated into a polyvinyl alcohol (PVA) and sodium alginate (SA) matrix, designed to enhance wound repair and mitigate inflammation. The characteristics of the hydrogel scaffold were observed including the degree of swelling and LNPs' release profiles. Furthermore, in the results, CBD/LNPs displayed enhanced stability and reduced cytotoxicity compared to unencapsulated CBD. In vitro assays demonstrated that CBD/LNPs significantly promoted fibroblast migration in gap-closure wound models and reduced intracellular reactive oxygen species, supporting their potential as a biocompatible and efficacious agent for cellular repair and oxidative stress attenuation. In vivo experiments using adult male Wistar rats with aseptic cutaneous wounds revealed that treatment with CBD/LNP-PVA/SA hydrogel scaffold significantly accelerated wound closure relative to blank hydrogel controls, demonstrating a substantial reduction in the wound area over time. Histological analysis confirms notable improvements in skin morphology in wounds treated with CBD/LNP-PVA/SA hydrogel scaffold with evidence of accelerated epithelialization, enhanced collagen deposition, and increased dermal thickness and vascularization. Additionally, skin histology showed a more organized epidermal layer and reduced inflammatory cell infiltration in CBD/LNP-PVA/SA hydrogel scaffold-treated wounds, corresponding to a 35% increase in the wound closure rate by day 28 post-treatment. These findings suggest that CBD/LNP-PVA/SA hydrogel scaffolds facilitate inflammation resolution and structural wound healing through localized, sustained CBD delivery. The dual anti-inflammatory and wound-healing effects position CBD/LNP-PVA/SA hydrogel scaffold as a promising approach for chronic wound management. Future investigations are warranted to elucidate the mechanistic pathways by which CBD modulates the skin architecture and to explore its translational applications in clinical wound care.

Suprathel® and water-filtered infrared-A radiation (wIRA) as a new treatment strategy for toxic epidermal necrolysis (TEN): A prospective study

Toxic epidermal necrolysis (TEN) is a life-threatening condition with a mortality rate of approximately 25 % to 30 %. Early and adequate wound coverage is necessary due to large skin defects. Suprathel® is a modern wound dressing that shows promising results when treating superficial wounds such as scalds, burns and abrasions. Previous reports on wound care in TEN patients using Suprathel® have described radical debridement of the entire affected body surface prior to the application of Suprathel®. However, heavy wound secretion in TEN may result in the loss of a significant portion of Suprathel® over time. Prolonged operation time increases the risk of hypothermia. In addition, the large open wound areas result in an increased risk for hypovolemic shock, wound infection, and subsequent sepsis. This study presents a new strategy that involves serial hydrotherapeutic wound debridement and the stepwise application of Suprathel® to the affected areas. Water-filtered infrared A light (wIRA) was used to keep the Suprathel®-covered areas dry. Retrospective data from patients who received polyhexanide gel treatment (control group 1) and those who only received Suprathel® (control group 2) were collected for matched-pair analysis. The length of stay in the intensive care unit (ICU) and the need for catecholamines were compared among the three groups. By using serial debridement and combining wIRA treatment with Suprathel® dressings, we were able to significantly reduce the need for catecholamines, lower the risk of hypothermia and infection, and shorten ICU stay compared to the two control groups. We propose incorporating this methodology into the standard of care to promote wound closure and healing when treating TEN patients.

Novel Insights into the Biological Activity of Croton lechleri Twigs Extracts and Advancements in Their Sustainable Recovery

Sangre de drago, the sap of Croton lechleri Müll. Arg. tree, has been used for centuries in traditional medicine owing to its diverse biological activities. Extracts derived from different parts of the species contain a multitude of phytochemicals with varied applications. Twigs, however, are among the least studied parts of the plant. This study unveils new biological activities of Croton lechleri twig extracts recovered by applying Soxhlet and advanced green techniques. For all extracts, total phenolic content and antioxidant activity were determined. Subsequently, four were selected, and their cytotoxic effects were assessed on both normal (HaCat) and malignant melanoma (A375) skin cell lines using the MTT assay and trypan blue exclusion assay. All showed dose-dependent cytotoxicity, with the Soxhlet ethanol extract demonstrating the highest selectivity towards A375 cells over HaCat cells. The extracts induced apoptosis and necrosis, as confirmed by Annexin V/PI dual-labeling and flow cytometry, highlighting their ability to trigger programmed cell death in cancer cells. The selective inhibition of cell cycle progression in A375 compared to HaCat observed both for Soxhlet ethanol and pressurized ethanol extracts induces cell cycle arrest at multiple points, primarily in the G1 and G2/M phases, and significantly reduces DNA synthesis as evidenced by the decrease in the S-phase population, confirmed by the EdU assay. Consequently, the Soxhlet extract composition was analyzed using LC-MS, which revealed their richness in polyphenolic compounds, particularly flavonoids from the flavonol subclass.

Water-filtered infrared A irradiation exerts antifungal effects on the skin fungus Malassezia

Many common skin diseases are associated with changes in the microbiota. This applies for the commensal yeast Malassezia, which is linked to a wide range of skin disorders ranging from mild dandruff to severe seborrheic and atopic dermatitis, all of which have a detrimental impact on the individuals' quality of life. While antifungal medications offer relief in many cases, the challenges of disease recurrence and the emergence of resistance to the limited range of available antifungal drugs poses a pressing need for innovative therapeutic options. Here we examined the activity of water-filtered infrared A (wIRA) irradiation against Malassezia. wIRA's antimicrobial and wound healing properties make it an attractive option for localized, non-invasive, and contact-free treatment of superficial skin infections. Irradiation of Malassezia furfur with wIRA (570-1400 nm) resulted in a reduction of the yeast's metabolic activity. When put in contact with immune cells, wIRA-irradiated M. furfur was recovered at lower counts than non-irradiated M. furfur. Likewise, wIRA irradiation of M. furfur put in contact with keratinocytes, the primary host interface of the fungus in the skin, reduced the fungal counts, while the keratinocytes were not affected by the irradiation. The combination of wIRA with the photosensitizer methyl aminolevulinate exerted an additional antifungal effect on M. furfur, irrespective of the presence or absence of keratinocytes, suggesting an enhancement of the treatment effect when used in combination. These findings suggest that wIRA holds promise as a potential therapy for skin disorders associated with Malassezia.

Development of silanized bacterial cellulose aerogels for the incorporation of natural oils with healing properties: Copaiba (Copaifera officinalis), bourbon geranium (Pelargonium X ssp.) essential oils and buriti (Mauritia flexuosa) vegetable oil

Bacterial cellulose (BC) represents a promising biomaterial, due to its unique and versatile properties. We report, herein, on purposely-designed structural modifications of BC that enhance its application as a wound dressing material. Chemical modification of the functional groups of BC was performed initially to introduce a hydrophobic/oleophilic character to its surface. Specifically, silanization was carried out in an aqueous medium using methyltrimethoxisilane (MTMS) as the silanizing agent, and aerogels were subsequently prepared by freeze-drying. The BC-MTMS aerogel obtained displayed a highly porous (99 %) and lightweight structure with an oil absorption capacity of up to 52 times its dry weight. The XRD pattern indicated that the characteristic crystallographic planes of the native BC were maintained after the silanization process. Thermal analysis showed that the thermal stability of the BC-MTMS aerogel increased, as compared to the pure BC aerogel (pBC). Moreover, the BC-MTMS aerogel was not cytotoxic to fibroblasts and keratinocytes. In the second step of the study, the incorporation of natural oils into the aerogel's matrix was found to endow antimicrobial and/or healing properties to BC-MTMS. Bourbon geranium (Pelargonium X ssp.) essential oil (GEO) was the only oil that exhibited antimicrobial activity against the tested microorganisms, whereas buriti (Mauritia flexuosa) vegetable oil (BVO) was non-cytotoxic to the cells. This study demonstrates that the characteristics of the BC structure can be modified, while preserving its intrinsic features, offering new possibilities for the development of BC-derived materials for specific applications in the biomedical field.

Improved in vitro wound healing in response to a superoxidised solution

OBJECTIVE

This study assessed wound healing in response to a superoxidised solution using an in vitro wound healing model.

METHOD

Prewounded reconstructed full-thickness human skin models were treated with 10µl of either superoxidised solution (Hydrocyn aqua, Bactiguard South East Asia Sdn. Bhd., Malaysia) or Dulbecco's phosphate buffered saline (DPBS) and incubated at 37°C for up to seven days, with additional treatments added every 48 hours. On days 0, 1, 2, 5 and 7, triplicate samples were taken for specific immunostaining against cytokeratin 14 and vimentin. At each timepoint, horizontal and vertical wound diameters were measured to demonstrate wound closure. Maintenance media was taken at the same timepoints for the measurement of secreted proinflammatory cytokines interleukin (IL)-1β, IL-6 and tumour necrosis factor (TNF)-ɑ.

RESULTS

At day 1, the superoxidised solution induced significantly lower diameter measurements compared with baseline data at day 0. Both treatment groups demonstrated significantly lower diameter measurements by day 2 when compared with the baseline; however, the average wound size of samples treated with the superoxidised solution was significantly lower when compared to the DPBS-treated group (p<0.05). No significant difference in expression of any proinflammatory was identified at any timepoint.

CONCLUSION

Application of the superoxidised solution resulted in significantly improved wound closure over the first 48 hours in comparison to DPBS-treatment. Furthermore, application of the superoxidised solution did not induce significant proinflammatory effects, despite the significantly reduced wound diameter.

Photobiomodulation and Wound Healing: Low-Level Laser Therapy at 661 nm in a Scratch Assay Keratinocyte Model

This study aims to investigate the effectiveness of low power red light (661 nm) in accelerating the wound healing process of an in vitro scratch assay model of keratinocytes. Furthermore, the study aims to clarify the role of light irradiation parameters, optimize them and gain additional insight into the mechanisms of wound closure as a result of photobiomodulation. Wound healing was studied using scratch assay model of NCTC 2544 keratinocytes. Cells were irradiated with a laser at various power densities and times. Images were acquired at 0, 24, 48 and 72 h following the laser treatment. Cellular proliferation was studied by MTT. ROS were studied at 0 and 24 h by fluorescence microscopy. Image analysis was used to determine the wound closure rates and quantify ROS. The energy range of 0.18-7.2 J/cm2 was not phototoxic, increased cell viability and promoted wound healing. Power and irradiation time proved to be more important than energy. The results indicated the existence of two thresholds in both power and irradiation time that need to be overcome to improve wound healing. An increase in ROS production was observed at 0 h only in the group with the lowest healing rate. This early response seemed to block proliferation and finally wound healing. Low level laser light at 661 nm enhanced both proliferation and migration in keratinocytes, providing evidence that it could possibly stimulate wound healing in vivo. The observed results are dependent on irradiance and irradiation time rather than energy dose in total.

Treatment with a red-laser-based wound therapy device exerts positive effects in models of delayed keratinocyte and fibroblast wound healing

BACKGROUND

Light therapy is widely used in medicine. Specifically, photobiomodulation has been shown to exert beneficial effects in wound healing disorders, which present a major challenge in health care. The study's aim was providing information on the effect of a novel, red-laser-based wound therapy device (WTD) on keratinocytes and fibroblasts during wound healing under optimal and non-optimal conditions.

METHODS

The scratch wound assay was employed as a wound healing model for mechanical damage with readjustment of specific cell milieus, explicitly chronic TH1 inflammation and TH2-dominant conditions. Furthermore, gene expression analysis of pro-inflammatory cytokines (IL1A, IL6, CXCL8), growth factors (TGFB1, PDGFC), transcription factors (NFKB1, TP53) and heat shock proteins (HSP90AA1, HSPA1A, HSPD1) as well as desmogleins (DSG1, DSG3) in keratinocytes and collagen (COL1A1, COL3A1) in fibroblasts was performed after WTD treatment.

RESULTS

It was shown that WTD treatment is biocompatible and supports scratch wound closure under non-optimal conditions. A distinct enhancement of desmoglein and collagen gene expression as well as induction of early growth factor gene expression was observed under chronic inflammatory conditions. Moreover, WTD increased HSPD1 transcript levels in keratinocytes and augmented collagen expression in fibroblasts during wound healing under TH2 conditions. WTD treatment also alleviated the inflammatory response in keratinocytes and induced early growth factor gene expression in fibroblasts under physiological conditions.

CONCLUSION

Positive effects described for wound treatment with WTD could be replicated in vitro and seem to be to be conferred by a direct influence on cellular processes taking place in keratinocytes and fibroblasts during wound healing.

Salvianolic acid B ameliorates myocardial fibrosis in diabetic cardiomyopathy by deubiquitinating Smad7

BACKGROUND

Salvianolic acid B (Sal B), a water-soluble phenolic compound derived from Salvia miltiorrhiza Bunge, is commonly used in Traditional Chinese Medicine to treat cardiovascular disease. In our previous study, Sal B protected against myocardial fibrosis induced by diabetic cardiomyopathy (DCM). This study aimed to investigate the ameliorative effects and potential mechanisms of Sal B in mitigating myocardial fibrosis induced by DCM.

METHODS

Various methods were used to investigate the effects of Sal B on myocardial fibrosis induced by DCM in vivo and in vitro. These methods included blood glucose measurement, echocardiography, HE staining, Masson's trichrome staining, Sirius red staining, cell proliferation assessment, determination of hydroxyproline levels, immunohistochemical staining, evaluation of fibrosis-related protein expression (Collagen-I, Collagen-III, TGF-β1, p-Smad3, Smad3, Smad7, and α-smooth muscle actin), analysis of Smad7 gene expression, and analysis of Smad7 ubiquitin modification.

RESULTS

The animal test results indicated that Sal B significantly improved cardiac function, inhibited collagen deposition and phenotypic transformation, and ameliorated myocardial fibrosis in DCM by upregulating Smad7, thereby inhibiting the TGF-β1 signaling pathway. In addition, cell experiments demonstrated that Sal B significantly inhibited the proliferation, migration, phenotypic transformation, and collagen secretion of cardiac fibroblasts (CFs) induced by high glucose (HG). Sal B significantly decreased the ubiquitination of Smad7 and stabilized the protein expression of Smad7, thereby increasing the protein expression of Smad7 in CFs and inhibiting the TGF-β1 signaling pathway, which may be the potential mechanism by which Sal B mitigates myocardial fibrosis induced by DCM.

CONCLUSION

This study revealed that Sal B can improve myocardial fibrosis in DCM by deubiquitinating Smad7, stabilizing the protein expression of Smad7, and blocking the TGF-β1 signaling pathway.

Development and characterization of a poloxamer hydrogel composed of human mesenchymal stromal cells (hMSCs) for reepithelization of skin injuries

Wound healing is a natural physiological reaction to tissue injury. Hydrogels show attractive advantages in wound healing not only due to their biodegradability, biocompatibility and permeability but also because provide an excellent environment for cell migration and proliferation. The main objective of the present study was the design and characterization of a hydrogel loaded with human mesenchymal stromal cells (hMSCs) for use in would healing of superficial skin injures. Poloxamer 407® was used as biocompatible biomaterial to embed hMSCs. The developed hydrogel containing 20 % (w/w) of polymer resulted in the best formulation with respect to physical, mechanical, morphological and biological properties. Its high swelling capacity confirmed the hydrogel's capacity to absorb wounds' exudate. LIVE/DEAD® assay confirm that hMSCs remained viable for at least 48 h when loaded into the hydrogels. Adding increasing concentrations of hMSCs-loaded hydrogel to the epithelium did not affect keratinocytes' viability and healing capacity and all wound area was closed in less than one day. Our study opens opportunities to exploit poloxamer hydrogels as cell carriers for the treatment of skin superficial wound.

Biodegradable piezoelectric skin-wound scaffold

Electrical stimulation (ES) induces wound healing and skin regeneration. Combining ES with the tissue-engineering approach, which relies on biomaterials to construct a replacement tissue graft, could offer a self-stimulated scaffold to heal skin-wounds without using potentially toxic growth factors and exogenous cells. Unfortunately, current ES technologies are either ineffective (external stimulations) or unsafe (implanted electrical devices using toxic batteries). Hence, we propose a novel wound-healing strategy that integrates ES with tissue engineering techniques by utilizing a biodegradable self-charged piezoelectric PLLA (Poly (l-lactic acid)) nanofiber matrix. This unique, safe, and stable piezoelectric scaffold can be activated by an external ultrasound (US) to produce well-controlled surface-charges with different polarities, thus serving multiple functions to suppress bacterial growth (negative surface charge) and promote skin regeneration (positive surface charge) at the same time. We demonstrate that the scaffold activated by low intensity/low frequency US can facilitate the proliferation of fibroblast/epithelial cells, enhance expression of genes (collagen I, III, and fibronectin) typical for the wound healing process, and suppress the growth of S. aureus and P. aeruginosa bacteria in vitro simultaneously. This approach induces rapid skin regeneration in a critical-sized skin wound mouse model in vivo. The piezoelectric PLLA skin scaffold thus assumes the role of a multi-tasking, biodegradable, battery-free electrical stimulator which is important for skin-wound healing and bacterial infection prevention simultaneuosly.

Glycolipid Biosurfactants in Skincare Applications: Challenges and Recommendations for Future Exploitation

The 21st century has seen a substantial increase in the industrial applications of glycolipid biosurfactant technology. The market value of the glycolipid class of molecules, sophorolipids, was estimated to be USD 409.84 million in 2021, with that of rhamnolipid molecules projected to reach USD 2.7 billion by 2026. In the skincare industry, sophorolipid and rhamnolipid biosurfactants have demonstrated the potential to offer a natural, sustainable, and skin-compatible alternative to synthetically derived surfactant compounds. However, there are still many barriers to the wide-scale market adoption of glycolipid technology. These barriers include low product yield (particularly for rhamnolipids) and potential pathogenicity of some native glycolipid-producing microorganisms. Additionally, the use of impure preparations and/or poorly characterised congeners as well as low-throughput methodologies in the safety and bioactivity assessment of sophorolipids and rhamnolipids challenges their increased utilisation in both academic research and skincare applications. This review considers the current trend towards the utilisation of sophorolipid and rhamnolipid biosurfactants as substitutes to synthetically derived surfactant molecules in skincare applications, the challenges associated with their application, and relevant solutions proposed by the biotechnology industry. In addition, we recommend experimental techniques/methodologies, which, if employed, could contribute significantly to increasing the acceptance of glycolipid biosurfactants for use in skincare applications while maintaining consistency in biosurfactant research outputs.

A new animal product free defined medium for 2D and 3D culturing of normal and cancer cells to study cell proliferation and migration as well as dose response to chemical treatment

Cell culturing methods are increasingly used to reduce and replace the use of live animals in biomedical research and chemical toxicity testing. Although live animals are avoided when using cell culturing methods, they often contain animal-derived components of which one of the most commonly used is foetal bovine serum (FBS). FBS is added to cell culture media among other supplements to support cell attachment/spreading and cell proliferation. The safety, batch-to-batch variation, and ethical problems with FBS are acknowledged and therefore world-wide efforts are ongoing to produce FBS free media. Here, we present the composition of a new defined medium with only human proteins either recombinant or derived from human tissues. This defined medium supports long-term culturing/routine culturing of normal cells and of cancer cells, and can be used for freezing and thawing of cells, i.e. for cell banking. Here, we show for our defined medium, growth curves and dose response curves of cells grown in two and three dimensions, and applications such as cell migration. Cell morphology was studied in real time by phase contrast and phase holographic microscopy time-lapse imaging. The cell lines used are human cancer-associated fibroblasts, keratinocytes, breast cancer JIMT-1 and MDA-MB-231 cells, colon cancer CaCo-2 cells, and pancreatic cancer MiaPaCa-2 cells as well as the mouse L929 cell line. In conclusion, we present the composition of a defined medium without animal-derived products which can be used for routine culturing and in experimental settings for normal cells and for cancer cells, i.e. our defined medium provides a leap towards a universal animal product free cell culture medium.

Investigation of the keratinocyte transcriptome altered in high-glucose environment: An in-vitro model system for precision medicine

BACKGROUND

Impaired wound healing is a serious diabetes complication compromising patients' quality of life. However, the pathogenesis of diabetic wounds (DWs) remains incompletely understood. Human epidermal keratinocyte (HEK) is the sentinel cell that initiates healing processes after the epidermal integrity has been disrupted.

OBJECTIVE

This study aimed to investigate the functional roles of HEKs in wound healing and to identify candidate genes, signaling pathways and molecular signatures contributing to the DWs.

METHODS

HEKs were cultured in normal or high-glucose environment, followed by scratch, to mimic the microenvironment of normal wounds and DWs. Subsequently, we performed RNA sequencing and systematically analyzed the expression profiles by bioinformatics approaches.

RESULTS

High-glucose environment altered the keratinocyte transcriptome responses to wounding. In experimental model of DWs, we found that TNF, CYP24A1, NR4A3 and GGT1 were key overexpressed genes in keratinocytes and were implicated in multiple cellular responses. Further analysis showed that wounding in high-glucose environment activated G-protein-coupled receptor (GPCR) signaling, cAMP response element-binding protein (CREB) signaling, and adrenomedullin signaling in keratinocytes, while dysregulated skin development and immune responses as compared to their counterpart in normal glucose settings.

CONCLUSION

This simplified in-vitro model serves as a valuable tool to gain insights into the molecular basis of DWs and to facilitate establishment of personalized therapies in clinical practice.

Effects of Histamine and the α-Tocopherol Metabolite α-13'-COOH in an Atopic Dermatitis Full-Thickness Skin Model

Atopic dermatitis is a T-cell mediated inflammatory skin disease with detected elevated levels of histamine in skin or plasma. In this study, the effects of histamine in a T_H2 cytokine environment on human keratinocytes and three-dimensional skin models were investigated. These models were used to explore the anti-inflammatory properties of the α-tocopherol-derived long-chain metabolite α-13'-carboxychromanol (α-13'-COOH). Histamine and T_H2 cytokine-induced proliferation of keratinocytes was studied using a scratch assay. The inflammatory marker interleukin-8 was significantly increased in healthy and T_H2 cytokine-stimulated keratinocytes and skin models after histamine treatment. The incubation of full-thickness skin models with T_H2 cytokines and histamine resulted in morphological changes in the epidermal layer, interpreted as hyperkeratosis. α-13'-COOH significantly decreased interleukin-8 in these disease-associated skin models. Histological staining of filaggrin showed skin-strengthening effects following α-13'-COOH treatment, without changes in mRNA expression. Cytokeratin 10 mRNA expression tended to be increased in response to α-13'-COOH. Anti-allergic properties of α-13'-COOH were studied by pre-incubation of human leukocytes with α-13'-COOH. This resulted in reduced sulfido-leukotriene synthesis. The hyperproliferation effect of histamine in atopic dermatitis skin models may be of further interest to the study of disease-associated morphological changes. Moreover, α-13'-COOH is a promising natural compound for the treatment of inflammatory skin diseases.

Replacement in angiogenesis research: Studying mechanisms of blood vessel development by animal-free in vitro, in vivo and in silico approaches

Angiogenesis, the development of new blood vessels from pre-existing ones, is an essential process determining numerous physiological and pathological conditions. Accordingly, there is a high demand for research approaches allowing the investigation of angiogenic mechanisms and the assessment of pro- and anti-angiogenic therapeutics. The present review provides a selective overview and critical discussion of such approaches, which, in line with the 3R principle, all share the common feature that they are not based on animal experiments. They include in vitro assays to study the viability, proliferation, migration, tube formation and sprouting activity of endothelial cells in two- and three-dimensional environments, the degradation of extracellular matrix compounds as well as the impact of hemodynamic forces on blood vessel formation. These assays can be complemented by in vivo analyses of microvascular network formation in the chorioallantoic membrane assay and early stages of zebrafish larvae. In addition, the combination of experimental data and physical laws enables the mathematical modeling of tissue-specific vascularization, blood flow patterns, interstitial fluid flow as well as oxygen, nutrient and drug distribution. All these animal-free approaches markedly contribute to an improved understanding of fundamental biological mechanisms underlying angiogenesis. Hence, they do not only represent essential tools in basic science but also in early stages of drug development. Moreover, their advancement bears the great potential to analyze angiogenesis in all its complexity and, thus, to make animal experiments superfluous in the future.

Molecular Research on Oral Diseases and Related Biomaterials: A Journey from Oral Cell Models to Advanced Regenerative Perspectives

Oral diseases such as gingivitis, periodontitis, and oral cancer affect millions of people worldwide. Much research has been conducted to understand the pathogenetic mechanisms of these diseases and translate this knowledge into therapeutics. This review aims to take the reader on a journey from the initial molecular discoveries to complex regenerative issues in oral medicine. For this, a semi-systematic literature search was carried out in Medline and Web of Science databases to retrieve the primary literature describing oral cell models and biomaterial applications in oral regenerative medicine. First, an in vitro cell model of gingival keratinocytes is discussed, which illustrates patho- and physiologic principles in the context of oral epithelial homeostasis and carcinogenesis and represents a cellular tool to understand biomaterial-based approaches for periodontal tissue regeneration. Consequently, a layered gradient nonwoven (LGN) is described, which demonstrates that the key features of biomaterials serve as candidates for oral tissue regeneration. LGN supports proper tissue formation and obeys the important principles for molecular mechanotransduction. Furthermore, current biomaterial-based tissue regeneration trends, including polymer modifications, cell-based treatments, antimicrobial peptides and optogenetics, are introduced to represent the full spectrum of current approaches to oral disease mitigation and prevention. Altogether, this review is a foray through established and new concepts in oral regenerative medicine and illustrates the process of knowledge translation from basic molecular and cell biological research to future clinical applications.