Dermal Layer Research Articles

Role of mesenchymal stem cell conditioned medium on wound healing using a developed 3D skin model.

Alternative 3-dimensional (3D) skin models that replicate in vivo human skin are required to investigate important events during wound healing, such as collective cell migration, epidermal layer formation, dermal substrate formation, re-epithelialisation and collagen production. In this study, a matched human 3D skin equivalent model (3D-SEM) was developed from human skin cells (fibroblast and keratinocytes), characterised using haematoxylin and eosin, immunofluorescence staining and microRNA profiling. The 3D-SEM was then functionally tested for its use in wound healing studies. Mesenchymal stem cells (MSCs) were isolated and characterised according to the criteria stipulated by the International Society for Cell Therapy. Cytokine and growth factor secretions were analysed by enzyme-linked immunosorbent assay. MSC-conditioned medium (MSC-CM) was then tested for wound healing capacity using the developed 3D-SEM at different timepoints i.e., at one, two and four weeks. The constructed 3D-SEM showed consistent development of skin-like structures composed of dermal layers and epidermal layers, with the ability to express epidermal differentiation markers and full stratification. They also showed prolonged longevity in culture media, retaining full differentiation and stratification within the four weeks. MicroRNA profiling revealed a strong correlation in microRNA expression between the developed 3D-SEM and the original native skin (p<0.001; R=0.64). Additionally, MSC-CM significantly enhanced migration, proliferation and differentiation of epidermal cells in the wounded models compared to control models at the different timepoints. In conclusion, in this study, the developed 3D-SEM mimicked native skin at the cellular and molecular levels, and clearly showed the important stages of skin regeneration during the healing process. MSC secretome contains growth factors that play a pivotal role in the healing process and could be used as a therapeutic option to accelerate skin healing.

Pitting Is Not Only a Measure of Oedema Presence: Using High-Frequency Ultrasound to Guide Pitting Test Standardisation for Assessment of Lymphoedema.

The pitting qualities of lymphoedema tissue change with disease progression. However, little is known about the underlying tissue response to the pitting test or the tissue characteristics that enhance or resist indentation. The pitting test is currently unstandardised, and the influence of test technique on pitting outcomes is unknown. Understanding how tissue reacts to applied pressure will build evidence for the standardisation of the pitting test. Ninety pitting test sites from fifteen women with unilateral breast cancer-related lymphoedema were evaluated using high-frequency ultrasound (HFUS), bioelectrical impedance spectroscopy (BIS), and limb volume measures. Three sites on each lymphoedema and non-lymphoedema arm were subject to a 60-s (s) staged pitting test, with changes in tissue features captured with ultrasound imaging before, throughout, and after the pitting test. Pitting qualities of tissues varied greatly, with lymphoedema sites pitting more frequently (p < 0.001) with greater depth (p < 0.001) and requiring a longer recovery time (p = 0.002) than contralateral unaffected tissue. Pitting is not solely attributable to oedema volume. Non-structural and structural characteristics of dermal and subcutaneous layers also influence tissue responses to sustained pressure. To enhance the validity and reliability of pitting assessment, a 60 s staged pitting test with an observation of tissue recovery is recommended for lymphoedema presentations.

How to Keep Myofibroblasts under Control: Culture of Mouse Skin Fibroblasts on Soft Substrates

During the physiological healing of skin wounds, fibroblasts recruited from the uninjured adjacent dermis and deeper subcutaneous fascia layers are transiently activated into myofibroblasts to first secrete and then contract collagen-rich extracellular matrix into a mechanically resistant scar. Scar tissue restores skin integrity after damage but comes at the expense of poor esthetics and loss of tissue function. Stiff scar matrix also mechanically activates various precursor cells into myofibroblasts in a positive feedback loop. Persistent myofibroblast activation results in pathologic accumulation of fibrous collagen and hypertrophic scarring, called fibrosis. Consequently, the mechanisms of fibroblast-to-myofibroblast activation and persistence are studied to develop antifibrotic and prohealing treatments. Mechanistic understanding often starts in a plastic cell culture dish. This can be problematic because contact of fibroblasts with tissue culture plastic or glass surfaces invariably generates myofibroblast phenotypes in standard culture. We describe a straight-forward method to produce soft cell culture surfaces for fibroblast isolation and continued culture and highlight key advantages and limitations of the approach. Adding a layer of elastic silicone polymer tunable to the softness of normal skin and the stiffness of pathologic scars allows to control mechanical fibroblast activation while preserving the simplicity of conventional 2-dimensional cell culture.

Multifunctional hierarchical electronic skins: Unveiling self-repairing mechanisms and advancements in sensing and shielding performance

In light of advancements in electronic skins (E-skins), their application in extreme environments poses significant challenges. Inspired by real human skin, we have developed a hierarchical structured electronic skin that utilizes flexible carbon fiber fabric as a framework. Copper nanoflakes and embedded sensors function as the neural layer, while Ethylene Vinyl Acetate acts as the dermal layer, and Polytetrafluoroethylene is employed as the epidermal layer. The reported E-skin demonstrates outstanding flexibility, excellent heat resistance, robust mechanical properties (fracture strength of 1600 MPa, Young's modulus approximately 3.8 GPa), exceptional bending/compression strain performance, excellent hydrophobicity (water contact angle of 120°), effective electromagnetic shielding performance (approximately 45 dB total shielding effectiveness for X-band), and electromagnetic wave absorption capability. Additionally, this E-skin possesses self-healing properties, capable of restoring to its original hydrophobic state within 30 s under a 9V voltage through the Joule heating effect, complemented by corresponding theoretical and mathematical modeling. This E-skin introduces a novel, environmentally friendly, and operationally simple strategy for enhancing the extreme environment resistance and durability of flexible devices.

Deletion of adipocyte Sine Oculis Homeobox Homolog 1 prevents lipolysis and attenuates skin fibrosis.

Dermal fibrosis is a cardinal feature of systemic sclerosis (SSc) for which there are limited treatment strategies. This is in part due to our fragmented understanding of how dermal white adipose tissue (DWAT) contributes to skin fibrosis. We identified elevated sine oculis homeobox homolog 1 (SIX1) expression in SSc skin samples from the GENISOS and PRESS cohorts, the expression of which correlated with adipose-associated genes and molecular pathways. SIX1 localization studies identified increased signals in the DWAT area in SSc and in experimental models of skin fibrosis. Global and adipocyte specific Six1 deletion abrogated end-stage fibrotic gene expression and dermal adipocyte shrinkage induced by SQ bleomycin treatment. Further studies revealed a link between elevated SIX1 and increased expression of SERPINE1 and its protein PAI-1 which are known pro-fibrotic mediators. However, SIX1 deletion did not appear to affect cellular trans differentiation. Taken together these results point at SIX1 as a potential target for dermal fibrosis in SSc.

A Look Inside-Histopathological Examinations of Different Tail Tip Lesions in Dairy Cows.

Feedlot cattle are frequently affected by inflammation and necrosis of the tail tips, resulting in impeded animal welfare and economic losses. In a recent study, it was demonstrated that dairy cows are also affected by different lesions of the tail tip, including alopecia, annular constrictions, crusting, scaling and swelling. Despite the frequent occurrence of these lesions, the underlying etiology and pathomechanisms are unclear to date. To gain insight into this malady, we histopathologically examined 16 tail tips of slaughtered dairy cows, representing the entire range of different lesions. While macroscopically alopecic areas were characterized by the formation of granulation tissue in the dermis with an inconspicuous epidermis, we found not only dermal granulation tissue but also purulent-necrotizing inflammation with the breakdown of the basement membrane in encrusted lesions. Interestingly, in some cases, we found areas of coagulation necrosis of the epidermal and dermal layers in the crusts. Tails with macroscopical scaling were affected by ortho- and/or parakeratotic hyperkeratosis, and, in tails with macroscopical swelling, we observed a low-protein edema of the central longitudinal connective tissue of the tail. We conclude that the observed lesions might be caused by ischemia of the skin in the distal parts of the tail.

Aged Human Dermal Extracellular Matrix as an Innovative Scaffold for Aging on Chip Model

Currently, there is a growing demand for developing innovative biomaterials that represent skin microenvironment more realistically. Here, we present an optimised protocol to extract and characterize an innovative human adult dermal extracellular matrix scaffold to represent the dermal layer in advanced 3D skin models.

Treatment of Iron-Induced Cutaneous Hyperpigmentation With Energy-Based Devices.

Iatrogenic cutaneous siderosis is a well-recognized dermatologic complication after parenteral iron infusion. The condition manifests as discrete, hyperpigmented patches near the site of injection. Most cases do not resolve spontaneously, leading to significant aesthetic and psychological distress to patients. A recent case of iatrogenic cutaneous siderosis at our institution prompted a systematic review of the efficacy of energy-based devices previously reported in the treatment of this condition. PubMed and Cochrane databases were searched for all peer-reviewed articles published using the following search terms: "iron OR heme OR hemosiderosis OR siderosis" and "hyperpigmentation OR staining OR tattoo." Articles reporting on energy-based devices in the treatment of iron-induced hyperpigmentation were included. A total of seven articles and 54 total patients were included in this review. All patients, including the patient treated at our institution, were female, with an average age of 44 years. Hyperpigmentation was most commonly associated with intravenous iron infusion (48/54, 89%), on the arm or forearm (44/54, 81%), and used for the treatment of underlying iron deficiency anemia (54/54, 100%). The application of six different nanosecond or picosecond quality-switched laser systems was reported in the treatment of cutaneous siderosis, with wavelengths ranging from 532 to 1064 nm. Spot sizes varied between 2 and 7 mm, with energy fluences spanning 0.5-40 J/cm2 depending on both the device and spot size. Outcomes were measured after an average of 5.4 laser treatments and 10.4 months, with over half of all reported patients experiencing complete clearance (27/50, 54%). Our patient received treatment inthree test areas withpicosecond alexandrite 785 nm, nanosecond Nd:YAG 532 nm, and picosecond Nd:YAG 532 nm devices. The nanosecond Nd:YAG 532 nm treated area demonstrated the greatest improvement,and the entire arm was subsequently treated with this device. Despite the often intractable nature of iatrogenic cutaneous siderosis, laser surgery is a reasonable and safe treatment modality for patients seeking cosmetic improvement of this dyschromia. Dermatologists should be aware of this entity and the efficacy of the energy-based devices currently in our armamentarium. A combination approach may need to be utilized with different wavelengths and pulsed widths to target iron pigment in both dermal and subcutaneous layers.

Engineered Exosomes Biopotentiated Hydrogel Promote Hair Follicle Growth via Reprogramming the Perifollicular Microenvironment.

Androgenetic alopecia (AGA) is a highly prevalent condition in contemporary society. The conventional treatment of minoxidil tincture is hindered by issues such as skin irritation caused by ethanol, non-specific accumulation in hair follicles, and short retention due to its liquid form. Herein, we have developed a novel minoxidil-incorporated engineered exosomes biopotentiated hydrogel (Gel@MNs) that has the capability to modulate the perifollicular microenvironment for the treatment of AGA. Leveraging the exceptional skin penetration abilities of flexible liposomes and the targeting properties of exosomes, the encapsulated minoxidil can be effectively delivered to the hair follicles. In comparison to free minoxidil, Gel@MNs demonstrated accelerated hair regeneration in an AGA mouse model without causing significant skin irritation. This was evidenced by an increase in both the number and size of hair follicles within the dermal layer, enhanced capillary formation surrounding the follicles, and the regulation of the transition of hair follicle cells from the telogen phase to the anagen growth phase. Therefore, this safe and microenvironment-modifying hybrid exosome-embedded hydrogel shows promising potential for clinical treatment of AGA.

Adenosine A2A receptor activation regulates the M1 macrophages activation to initiate innate and adaptive immunity in psoriasis

Psoriasis is a common inflammatory systemic disease characterized by pro-inflammatory macrophages activation (M1 macrophage) infiltrated in the dermal layer. How M1 macrophage contributes to psoriasis remains unknown. In this study, we found that adenosine A2A receptor (A2AR) agonist CGS 21680 HCl alleviated the imiquimod (IMQ) and mouse IL-23 Protein (rmIL-23)-induced psoriasis inflammation through reducing infiltration of M1. Conversely, Adora2a deletion in mice exacerbated psoriasis-like phenotype. Mechanistically, A2AR activation inhibited M1 macrophage activation via the NF-κB-KRT16 pathway to reduce the secretion of CXCL10/11 and inhibit Th1/17 differentiation. Notably, the KRT16 expression was first found in M1 macrophage in our study, not only in keratinocytes (KCs). CXCL10/11 are first identified as primarily derived from macrophages and dendritic cells (DCs) rather than KCs in psoriasis using single cell RNA sequencing (scRNA-Seq). In total, the study emphasizes the importance of M1 as an innate immune cell in pathogenesis of psoriasis.

A multi-scale numerical study of monoclonal antibodies uptake by initial lymphatics after subcutaneous injection

This paper studies the transport of monoclonal antibodies through skin tissue and initial lymphatics, which impacts the pharmacokinetics of monoclonal antibodies. Our model integrates a macroscale representation of the entire skin tissue with a mesoscale model that focuses on the papillary dermis layer. Our results indicate that it takes hours for the drugs to disperse from the injection site to the papillary dermis before entering the initial lymphatics. Additionally, we observe an inhomogeneous drug distribution in the interstitial space of the papillary dermis, with higher drug concentrations near initial lymphatics and lower concentrations near blood capillaries. To validate our model, we compare our numerical simulation results with experimental data, finding a good alignment. Our parametric studies on the drug molecule properties and injection parameters suggest that a higher diffusion coefficient increases the transport and uptake rate while binding slows down these processes. Furthermore, shallower injection depths lead to faster lymphatic uptake, whereas the size of the injection plume has a minor effect on the uptake rate. These findings advance our understanding of drug transport and lymphatic absorption after subcutaneous injection, offering valuable insights for optimizing drug delivery strategies and the design of biotherapeutics.

On the Origin of the Photoplethysmography Signal: Modeling of Volumetric and Aggregation Effects

This study aimed to examine the mechanisms of the photoplethysmography (PPG) signal formation using Monte Carlo simulations of light transport in biological tissues and experimental observations. Based on a three-layer skin model in backscattering geometry, we sequentially simulated volumetric blood changes and the aggregation/disaggregation of erythrocytes in the dermal layer and estimated their contribution to the registered PPG signal. The calculations were conducted for two wavelengths: 525 nm and 810 nm. For green light, absorption predominates over scattering in the formation of a PPG signal, whereas, for near-infrared light, scattering prevails over absorption. This theoretical result was verified using the Modified Beer–Lambert law and clinical in vivo PPG data of seven healthy subjects. Changes in the size of the scatterers during erythrocyte aggregation and disaggregation can significantly contribute to the PPG signal at near-infrared light. Thus, for the green waveband, the classical volumetric model can be considered dominant in the PPG signal formation. In contrast, for the near-infrared range, both volumetric and aggregation effects must be considered as being approximately equal.

Detection of anaerobic and aerobic bacteria from commercial tattoo and permanent makeup inks.

The rising popularity of tattooing and permanent makeup (PMU) has led to increased reports of ink-related infections. This study is the first to investigate the presence of both aerobic and anaerobic bacteria in commercial tattoo and PMU inks under aerobic and anaerobic conditions. Our findings reveal that unopened and sealed tattoo inks can harbor anaerobic bacteria, known to thrive in low-oxygen environments, such as the dermal layer of the skin, alongside aerobic bacteria. This suggests that contaminated tattoo inks could be a source of infection from both types of bacteria. The results emphasize the importance of monitoring these products for both aerobic and anaerobic bacteria, including possibly pathogenic microorganisms.

Does hydrogen peroxide help mitigate the incidence of Cutibacterium acnes in cervical spine surgeries?

Background: Surgical site infection (SSI) is a common yet serious complication of cervical spine surgery. While initially thought to be clinically insignificant, Cutibacterium acnes (C. acnes) is an important cause of infection. The purpose of this study was to investigate the ability of an hydrogen peroxide (H2O2) application during standard pre-surgical skin preparation to reduce the burden of C. acnes in patients undergoing cervical spine surgery. Methods: This was a retrospective review of prospectively collected data. Subjects were randomly assigned to either standard surgical preparation plus H2O2 (experimental) or without H2O2 (control). Pre-scrub, post-scrub, and dermal cultures were obtained to assess the C. acnes burden after cultures on an aerobic and anaerobic growth medium were held for 21 days. Multivariate analysis was conducted to determine factors associated with presence of C. acnes. Outcome measures included the results of intraoperative cultures and the development of a SSI within 90 days post-operatively. Results: Patients (n=86) undergoing elective two- or three-level fusion via anterior approach were included. Prior to application of the antiseptic solution, 65% (28/43) of the experimental cohort and 77% (33/43) of the control cohort had positive C. acnes cultures (p=0.34). Following application of antiseptic solution, there were no differences in positive C. acnes culture rates between the experimental and control cohorts in the epidermal (30% versus 28%, p=1.00) or dermal (40% versus 42%, p=1.00) cultures. No differences in the rates of C. acnes eradication from pre-antiseptic to post-antiseptic application occurred for epidermal (p= 1.00) or dermal (p= 1.00) skin layers. None of the factors were associated with positive C. acnes epidermal cultures on multivariable logistic regression analysis (p> 0.05). Conclusions: While there is potential for H2O2 to reduce the positive culture rate of C. acnes in cervical spine patients, no difference was seen when compared to standard surgical skin preparation.

Plasma treated‐double layer electrospun fiber mats from thermoplastic polyurethane and gelatin for wound healing applications

AbstractConventional wound treatment options provide a barrier against exogenous microbial penetration but cannot simultaneously provide an antibacterial characteristic and promote healing. However, bioactive dressings can accelerate wound healing and have an antibacterial effect in addition to being able to cover and protect lesions. In this study, double‐layer thermoplastic polyurethane (TPU)‐gelatin fibrous dressings that mimic the epidermis and dermis layers of the skin were fabricated via electrospinning technique. As a bioactive agent, Hypericum perforatum oil (HPO) was utilized to impart antibacterial and therapeutic properties to the dressings. Tannic acid was also used in fiber mat formulations as a cross‐linking agent. Oxygen plasma treatment was applied as a surface activation technique to improve adhesion of TPU and gelation layers. The fiber structure of the mats was revealed by a scanning electron microscopy (SEM) study. Fourier transform infrared (FTIR) spectroscopy was used to demonstrate HPO loading onto the mats. The water vapor transmission rate (WVTR) and fluid absorbency of the mats were compared with some commercial dressings. According to these results, it can be suggested that the mats can be used for moderate to high exudative wounds. All dressings, even the control sample showed antibacterial features against both Staphylococcus aureus and Escherichia coli bacteria due to the tannic acid. In vitro wound healing assays were carried out on the plasma‐treated sample and it was observed that the sample did not negatively affect the migration and proliferation abilities of the cells which are necessary for wound healing. Overall results indicated that the plasma‐treated fibrous mat would be a good candidate as a wound dressing material having an antibacterial character.

Development of Cutaneous Pseudolymphoma following Bee Sting: A Case Report

Cutaneous pseudolymphoma (CPL) is a benign skin disorder characterized by the presence of a lymphocyte-rich infiltrate resembling malignant lymphoma. As there are significant differences in management and clinical outcomes, differentiating CPL from true lymphomas is crucial. The diagnostic process involves a comprehensive approach, incorporating clinical examination, histopathological analysis, and when necessary, immunohistochemical staining to distinguish CPL from true lymphomas. Biopsy plays a key role in assessing characteristics of infiltrating lymphocytes and architectural arrangements of cells within dermal layers. Here, we present an unusual case of CPL triggered by a bee sting, outlining its clinical and pathological features.

Study of Histological Skin Structure of Python reticulatus and Varanus salvator

Reptile skin is covered with scales that form a protective barrier, making it waterproof and enabling life on land. The present study investigated the histological structure of the skin of the Python reticulatus and Varanus salvator. The samples used were Python reticulatus and Varanus salvator skin taken from the dorsal region. Preparations were made using the hematoxylin eosin (HE) staining method which was carried out at the Microbiology of the leather processing technology, Politeknik ATK Yogyakarta. The results showed that the histological structure of Python reticulatus skin consisted of two layers, epidermis and dermis. The epidermis was composed of stratum corneum, stratum granulosum, and stratum basale. The dermis consists of an outer layer called the stratum laxum (stratum spongiosum) and an inner layer called the stratum compactum. Meanwhile, the histological skin structure of Varanus salvator skin consists of epidermis which included oberhautchen, α-keratin layer, β-keratin layer, supra basale layer, and basale layer. The dermis consists of superficial dermis and deep dermis. There are differences between Python reticulatus skin that is distinguished by its ability to ecydis (skin shedding) the epidermis and Varanus salvator skin have osteoderm (OD) within their dermis layer

Natural Bioactive Compounds as Anti-aging Agents: Current and Future Perspectives

Abstract: Aging is a natural biological process that occurs due to various factors like unhealthy diet, environmental factors, genetic factors, and lack of moisture. This process leads to the loss of skin elasticity, also known as sagging. It happens due to the gradual decline of collagen type VII (Col-7) and fibril, which slows down the connection between the dermis and epidermis layers, causing the skin to look aged externally. There are several theories of aging, such as the free radical theory, membrane theory, DNA or genetic theory, neuroendocrine theory, telomerase theory, mitochondrial decline theory, and Hayflick limit theory. According to WHO, by 2030, one in six individuals worldwide will be 60 years or older. There are synthetic compounds available in the market for anti-aging purposes, but they pose various side effects. Natural products play an essential role in managing aging, and anti-aging phytoconstituents are mostly found in plant parts like fruits, stems, roots, and other plant sources that have no side effects. This review focuses on various anti-aging agents derived from plants and other natural sources.

Utilization of Box Behnken Design for the Development and Evaluation of Luliconazole-loaded Nanoemulgel

Pharmaceutical research is always looking for novel ways to distribute drugs and developing these methods to increase the effectiveness of existing medications. The physicochemical characteristics of the drug determine the dose form. Lipophilic API development is a result of recent discoveries in high-throughput screening. A topical broad-spectrum antifungal agent is luliconazole. Due to its lower water solubility, topical administration is limited, and topical absorption is confined. The stratum corneum’s lipid phase’s solubility of the medication also serves as a rate-limiting step for penetration. Because fungal infections impact the skin’s epidermis, dermis, and deeper layers, medicine administration must be tailored to target high drug concentrations at the layers of the epidermis and dermis

The Smart Drug Delivery of Rotigotine Using Transdermal Patch for the Successful Management of Parkinson's Disease.

A Non-Ergot Dopamine Agonist (NEDA) rotigotine has been designed as a new transdermal drug delivery system. To maintain optimum homogeneity in drug content, the rotigotine transdermal patch was developed utilizing a solvent casting technique. The characteristics of a transdermal patch, including patch weight, folding endurance, patch thickness, surface morphology, tensile strength, swelling rate, surface pH, in vitro release studies, water retention rate, uniformity of drug content, and ex-vivo permeation studies, were determined. In vitro drug release studies unequivocally demonstrated that drug release controlled polymer interactions. There was no apparent lag period before the drug release rate started to decline. The developed patch showed 70 ± 1.18 % of prolongation of drug release within 24 hours. The result of the penetration studies demonstrated that 61 ± 2.52% of rotigotine permeated through the epidermal barrier within 24 h. The developed transdermal patch comprising rotigotine was evidently placed on the dermis layer, and an appropriate dose was delivered into circulation for a longer time based on the aforementioned factors. The findings of this study illustrate the effective approach of transdermal patches to treat Parkinson's disease.