Fibroblasts and ascorbate regulate epidermalization in reconstructed human epidermis

Utilizing stem cell-secreted molecules as a versatile toolbox for skin regenerative medicine

Stem cells are recognized as an important target and tool in regenerative engineering. In this study, we explored the feasibility of engineering amniotic fluid-derived mesenchymal stem cell-secreted molecules (afMSC-SMs) as a versatile bioactive material for skin regenerative medicine applications in a time- and cost-efficient and straightforward manner. afMSC-SMs, obtained in powder form through ethanol precipitation, effectively contributed to preserving the self-renewal capacity and differentiation potential of primary human keratinocytes (pKCs) in a xeno-free environment, offering a potential alternative to traditional culture methods for their long-term in vitro expansion, and allowed them to reconstitute a fully stratified epithelium sheet on human dermal fibroblasts. Furthermore, we demonstrated the flexibility of afMSC-SMs in wound healing and hair regrowth through injectable hydrogel and nanogel-mediated transdermal delivery systems, respectively, expanding the pool of regenerative applications. This cell-free approach may offer several potential advantages, including streamlined manufacturing processes, scalability, controlled formulation, longer shelf lives, and mitigation of risks associated with living cell transplantation. Accordingly, afMSC-SMs could serve as a promising therapeutic toolbox for advancing cell-free regenerative medicine, simplifying their broad applicability in various clinical settings.

Influence of silymarin components on keratinocytes and 3D reconstructed epidermis

Silymarin is a flavonoid complex isolated from the plant Silybum marianum which is well known for its antioxidant, hepatoprotective and immunomodulatory effects. Since little is known about its anti-inflammatory properties and healing effects, our study focused on whether or not silymarin components reduce inflammation and support epidermis regeneration. Lipopolysaccharides (LPS) and sodium dodecyl sulfate (SDS) were used to induce inflammation in normal human epidermal keratinocytes (NHEKs) and reconstructed epidermis (RHE), respectively. The expression of pro-inflammatory cytokines (IL-1, IL-6 and IL-8) in NHEKs and RHE was measured by enzyme - linked immunosorbent assay (ELISA). The expression of cytokeratin 14 and loricrin in RHE was detected by immunofluorescent analysis. Hematoxylin and eosin staining was used for the morphological evaluation of RHE. It was determined that 2, 3 - dehydrosilybin (DHSB) downregulated the production of selected pro-inflammatory cytokines produced by NHEKs. Although all layers of RHE displayed full thickness, when SDS was applied, cell detachment was seen in the stratum corneum and loricrin expression was diminished.

Sandwich-structure transferable free-form OLEDs for wearable and disposable skin wound photomedicine

Free-form optoelectronic devices can provide hyper-connectivity over space and time. However, most conformable optoelectronic devices can only be fabricated on flat polymeric materials using low-temperature processes, limiting their application and forms. This paper presents free-form optoelectronic devices that are not dependent on the shape or material. For medical applications, the transferable OLED (10 μm) is formed in a sandwich structure with an ultra-thin transferable barrier (4.8 μm). The results showed that the fabricated sandwich-structure transferable OLED (STOLED) exhibit the same high-efficiency performance on cylindrical-shaped materials and on materials such as textile and paper. Because the neutral axis is freely adjustable using the sandwich structure, the textile-based OLED achieved both folding reliability and washing reliability, as well as a long operating life (>150 h). When keratinocytes were irradiated with red STOLED light, cell proliferation and cell migration increased by 26 and 32%, respectively. In the skin equivalent model, the epidermis thickness was increased by 39%; additionally, in organ culture, not only was the skin area increased by 14%, but also, re-epithelialization was highly induced. Based on the results, the STOLED is expected to be applicable in various wearable and disposable photomedical devices.

Improvement of skin barrier dysfunction by Scutellaria baicalensis GEOGI extracts through lactic acid fermentation

BACKGROUND

The development of an alternative medicine to treat atopic dermatitis (AD) from natural sources is necessary.

AIMS

To improve skin barrier dysfunction by enhancing the differentiation of human keratinocytes with the fermented Scutellaria baicalensis.

METHODS

Scutellaria baicalensis was fermented with Lactobacillus plantarum and extracted with 70% ethanol (FE). Antioxidant activities and the regulation of the gene expression related to keratinocyte differentiation were measured as well as its proliferation.

RESULT

This work first proved that the FE had multiple activities, both increasing keratinocyte differentiation and proliferation: The FE greatly up-regulated expression of the genes of keratinocyte differentiation such as involucrin, keratin 10, and transglutaminase-1 (TG-1) up to 4.06-fold, which was 3 times higher than the 2 other extracts. The effect of baicalein on keratinocyte differentiation was also first found; however, its efficacy was lower than that of the fermented extract. The FE proved to effectively accelerate keratinocyte differentiation, rather than to initiate the differentiation, and also showed an ability of stimulating keratinocyte proliferation up to 2.8 × 10⁶ viable cells/mL as well as 70.24 ng/mL of collagen production in fibroblasts. High efficacy of the FE was confirmed by synergistic effects of large amounts of various bioactive substances in the extracts as baicalein alone did not show remarkable effects and even positive controls had not much better activities than the FE.

CONCLUSION

The fermented extract was able to improve skin barrier dysfunction, and the ointment with 1%-5% (v/v) of the extract be directly used for skin clinical trials to treat AD.

Formation of keratinocyte multilayers on filters under airlifted or submerged culture conditions in medium containing calcium, ascorbic acid, and keratinocyte growth factor

Three-dimensional (3D) cell culture is a powerful in vitro technique to study the stratification and differentiation of keratinocytes. However, culture conditions, including culture media, supplements, and scaffolds (e.g., collagen gels with or without fibroblasts), can vary considerably. Here, we evaluated the roles of calcium, L-ascorbic acid phosphate magnesium salt n-hydrate (APM), and keratinocyte growth factor (KGF) in a chemically defined medium, EpiLife, in 3D cultures of primary human epidermal keratinocytes directly plated on polycarbonate filter inserts under airlifted or submerged conditions. Eight culture media containing various combinations of these three supplements were examined. Calcium was necessary for the stratification and differentiation of keratinocytes based on the localization of keratins and involucrin. However, the localization patterns of keratins and integrin β4 were partially disrupted and Ki67-positive basal cells almost disappeared 3 weeks after airlift. The addition of KGF, but not APM, prevented these changes. Further addition of APM markedly improved the tissue architecture, including basal cell morphology and the appearance of keratohyalin granules and localized involucrin in the upper suprabasal cells, even after 1 week. Although the submerged culture also formed cornified epithelium-like multilayers, involucrin was localized in the cornified layer, where nuclei were often found. Based on these results, it is most effective to culture keratinocytes at the air-liquid interface in EpiLife medium supplemented with calcium, APM, and KGF to form well-organized and orthokeratinized multilayers as skin analogues.

Fucoidan promotes the reconstruction of skin equivalents

In this study we investigated the effects of fucoidan on the proliferation of fibroblasts and the reconstruction of a skin equivalent (SE). Fucoidan significantly stimulated the proliferation of CCD-25Sk human fibroblasts and Western blot analysis demonstrated that fucoidan markedly increased the expression of cyclin D1 and decreased the expression of p27. Fucoidan was used to reconstruct SE. Immunohistochemical staining showed that the addition of fucoidan to dermal equivalents increased expression of proliferating cell nuclear antigen (PCNA) and p63. In addition, expression of α6-integrin was significantly increased by fucoidan, whereas expression of β1-integrin, type 1 collagen, elastin, fibronectin did not markedly change. These results suggest that fucoidan has positive effects on epidermal reconstruction and will therefore be beneficial in the reconstruction of SE.

Redox status is critical for stemness in skin equivalents

The skin is constantly exposed to environmental oxidative stress. Skin equivalent (SE) models are three-dimensional systems in which cell-cell or cell-matrix interactions can be investigated. In this study, the effects of vitamin C or plant extracts with high antioxidant activities were tested. There was no significant difference in the epidermal thickness, but the basal cells became cuboidal when vitamin C or plant extracts were supplemented. Furthermore, immunohistochemical staining showed linear and intense staining of α6 and β1 integrin along the basement membrane in vitamin C or plant extract treated models. The p63 and PCNA were also stained. Results showed that the number of p63 and PCNA positive cells was higher in the vitamin C or plant extract treated models than in the control SEs. Although the relationship between oxidative stress and stem cells is not known, our results suggest that redox status affects the stemness and the proliferative potential of epidermal basal cells by modulating microenvironment to epidermal basal stem cells.

"Multi Light and Drugs": a new technique to treat face photoaging. Comparative study with photorejuvenation

Nonablative skin rejuvenation using laser, intense pulsed lights (IPLs), or radiofrequency techniques are becoming increasingly popular. In this paper, a novel protocol that integrates IPL sessions, low intense light and vitamin C, low-weight hyaluronic acid, betaglucan dermal injection versus IPL photorejuvenation as monotherapy is compared. A group of 100 patients, all women, with ages ranging from 35 to 65 years old (median age 56.3) with different degrees of photodamage was considered. A blinded control study was done. The patients were divided not randomly into two groups. These groups are similar for ages, skin types, and degrees of photoaging distribution. A first group of 40 patients had monotherapy consisting of seven sessions of IPL only. A second group of 60 patients had triple therapy consisting of seven sessions of IPL as well as nine sessions of low intense diode light and also biostimulation by drugs. Considering only the improvement in hyperpigmentations and teleangectasias, the monotherapy and the triple therapy show good results with no significant statistical difference between the two groups. Considering the improvement in skin texture and firmness in the group treated only with monotherapy, 30% (12 patients) had positive results, and 70% (28 patients) had poor results. In the group treated with triple therapy, 70% (42 patients) had positive results, and 30% (18 patients) had poor results, with the main differences in skin silicone negative imprints. On the basis of the data presented, the new technique of IPL, low intensity diode light, and multidrugs biostimulation seems to be a safe and effective method for skin rejuvenation and upgrades the effects of IPL in the fibroblasts' stimulation.

Morphogenesis of dermal-epidermal junction in a model of reconstructed skin: beneficial effects of vitamin C

In skin, cohesion between the dermis and the epidermis is ensured by the dermal-epidermal junction which is also required for control of epidermal growth and differentiation. Here we showed that addition of vitamin C optimized the formation of the dermal-epidermal junction in an in vitro human reconstructed skin model leading to a structure closer to that of normal human skin. Compared with controls, vitamin C treatment led to a better organization of basal keratinocytes, an increase in fibroblast number and a faster formation of the dermal-epidermal junction. Vitamin C also accelerated deposition of several basement membrane proteins, like type IV and VII collagens, nidogen, laminin 10/11, procollagens I and III, tenascin C and fibrillin-1 at the dermal-epidermal junction. The mechanism of action of vitamin C was investigated by quantitative polymerase chain reaction in fibroblasts and keratinocytes respectively. Vitamin C effects passed in part through an increase in col I alpha1, col III alpha1 and fibrillin-1 mRNA levels. Effects on the other markers appeared to happen at the translational and/or post-translational level, as illustrated for tenascin C, col IV alpha2 and col VII alpha1 mRNA levels which were reduced by vitamin C in both cell types.

The Fixation of Living Skin Equivalents

Histologic evaluations and immunohistochemical characterizations are important in studies of artificial organs such as skin equivalents. However, tissue compact organization is not easy to obtain when the artificial organ is constructed in vitro. Thus, appropriate fixation methods must be selected according to the compactness of the artificial organ and tissue engineering methodologies. The effects of several fixatives-Carnoy, Bouin's solution, formalin, paraformaldehyde, and paraformaldehyde-glutaraldehyde-were examined to select the best fixation method for preserving the structural and molecular markers of skin equivalents. Formalin-based fixatives ware found to be relatively free of the histologic problems (e.g., tissue shrinkage, poor structural preservation, weak stainability, and nonspecific immunolocalization) presented by the soft tissue fixatives (i.e., Carnoy or Bouin's solution). Unfortunately, the standard concentration of formalin induced detachment of epidermis from dermis, but this was prevented by reducing the concentration of the fixative. These findings suggest that fixation procedures should be selected for particular tissue and specific goals; in particular, they show that the paraformaldehyde-glutaraldehyde combination performed best in terms of preserving the histologic features of skin equivalents.

A Reproducible Laser-Wounded Skin Equivalent Model to Study the Effects of AgingIn Vitro

Skin aging involves both chronological and photoaging processes. The effects of these processes are often overlapping and include changes in both the stratified epithelium and the fibroblast-rich dermis. Wound healing is frequently delayed with aging and can result in scarring. A skin equivalent model can be used to study the role of cells and the extracellular matrix in the process of wound healing. Current studies using this model employ a full-thickness wound placed atop a nonwounded dermis to mimic a partial-thickness wound. However, a true reproducible partial-thickness wound model has yet to be described. In this study, we investigated whether a laser-wounded skin equivalent would be a useful partial-thickness wound healing model. Three lasers were compared for the ability to generate a reproducible wound: an erbium-YAG, a high-powered excimer, and a low-powered excimer laser. Reepithelialization ability was tested using newborn and adult skin keratinocytes, adult esophageal keratinocytes, and cdk4-overexpressing newborn keratinocytes. Keratinocyte compartmentalization and basement membrane formation were assessed by immunofluorescence. The erbium-YAG and high-powered excimer laser cut reproducible wounds but left the remaining surface either discolored due to thermal damage and/or ragged; keratinocytes were unable to migrate into the wound area. The low-powered excimer laser cut reproducible wounds, leaving the cut surface intact and visibly unaltered; keratinocytes reepithelialized the wound in a collagenase-dependent manner within 3 days; and return of compartmentalization and basement membrane occurred within 14 days. The laser-wounded skin equivalent is an adjustable, reproducible partial-thickness wound model where keratinocyte biology akin to in vivo can be studied, and will be useful to study the effects of aging on wound healing.