Line-field confocal optical coherence tomography coupled with artificial intelligence algorithms to identify quantitative biomarkers of facial skin ageing

Quantitative biomarkers of facial skin ageing were studied from one hundred healthy Caucasian female volunteers, aged 20-70 years, using in vivo 3D Line-field Confocal Optical Coherence Tomography (LC-OCT) imaging coupled with Artificial Intelligence (AI)-based quantification algorithms. Layer metrics, i.e. stratum corneum thickness (SC), viable epidermal thickness and Dermal-Epidermal Junction (DEJ) undulation, as well as cellular metrics were measured for the temple, cheekbone and mandible. For all three investigated facial areas, minimal age-related variations were observed in the thickness of the SC and viable epidermis layers. A flatter and more homogeneous epidermis (decrease in the standard deviation of the number of layers means), a less dense cellular network with fewer cells per layer (decrease in cell surface density), and larger and more heterogeneous nuclei within each layer (increase in nuclei volume and their standard deviation) were found with significant variations with age. The higher atypia scores further reflected the heterogeneity of nuclei throughout the viable epidermis. The 3D visualisation of fine structures in the skin at the micrometric resolution and the 1200 µm × 500 µm field of view achieved with LC-OCT imaging enabled to compute relevant quantitative biomarkers for a better understanding of skin biology and the ageing process in vivo.

Epidermal thickness in healthy humans: A systematic review and meta-analysis

Several skin diseases are characterised by epidermal alterations affecting epidermal thickness. Reference values of epidermal thickness in healthy humans and knowledge of possible differences regarding age, sex, skin phototype, and ethnic origin are essential in research and in clinical practice. The objectives of this systematic review were to provide epidermal thickness reference values for healthy human skin and describe possible effects of measurement methods, age, sex, ethnic origin, and skin phototype. A combined search in the databases Medline and Embase, and other sources was conducted. Searches covered a period from 1946 to 3^rd June 2020. Included studies were primary observational and interventional studies providing means and spread values of epidermal thickness estimates in healthy humans, with clear reporting of skin area, age and measurement method, and optional reporting of sex, ethnic origin and skin phototype. Data were extracted per skin area and pooled in random-effects models. 142 studies were included in the qualitative synthesis and 133 in the meta-analysis. Pooled epidermal thickness estimates were calculated for 37 skin areas. The lowest epidermal thickness of 31.2 (95% CI 27.8 to 34.6) μm was reported for the penis, and the highest of 596.6 (95% CI 443.9 to 749.3) μm for the plantar aspect of the foot. Differences of epidermal thickness estimates obtained by histology, optical coherence tomography and laser scanning microscopy were minor. High-frequency ultrasonography produces systematically higher values. Epidermis was thinner in aged skin. Differences between sexes and among ethnic origins where minor. Epidermal thickness reference values are provided for 37 skin areas. In conclusion, the epidermis tends to become thinner by ageing and does not seem to be influenced by sex. Histology, optical coherence tomography and laser scanning microscopy might be used interchangeably to measure epidermal thickness, whereas high-frequency ultrasound should not be used.

Standardized Terminalia chebula Fruit Extract: A Natural Ingredient That Provides Long-Lasting Antioxidant Protection and Reverses Visible Signs of Pollution-Induced Skin Damage

Background

Identification of long-lasting natural antioxidants to protect against and repair skin damage induced by exposure to environmental pollution is in high demand.

Objective

To investigate a standardized Terminalia chebula (TC) fruit extract for its long-lasting antioxidant and anti-inflammatory properties and its ability to reverse the visible signs of pollution-induced skin damage in an 8-week clinical study.

Material and Methods

Chemical and cell-based in vitro studies were performed to characterize long-lasting antioxidant and anti-inflammatory properties; a clinical study with subjects with normal to dry skin living in a high-pollution city for the previous 5 years was conducted to assess if a formulation containing 1% standardized TC fruit extract affected significant improvements in skin’s visible condition and appearance compared with its placebo.

Results

The standardized TC fruit extract provided longer-lasting and more efficient neutralization of reactive oxygen species (ROS) than tocopherol; treatment of keratinocytes with the fruit extract prior to being stressed with urban dust safeguarded against increases in intracellular ROS, inhibited release of inflammatory cytokines IL-6 and IL-8 and protected membrane lipids against peroxidation. A clinical study yielded statistically significant improvements in dermatologist scores and subject self-assessments for skin texture, hydration, tone, firmness and radiance as compared to its placebo.

Conclusion

These studies validate the use of this standardized TC fruit extract not only as a restorative to diminish visible signs of existing damage but also as a preventative to help defend skin against damages caused by chronic exposure to environmental pollution.

Safety and efficacy of a novel home-use device for light-potentiated (LED) skin treatment

Skin structure and function results from a dynamic interplay between dermal and epidermal cell types. Optimizing skin health through an effective and long-lasting skin care regime therefore requires a global approach, encompassing various mechanisms to stimulate this interplay beyond the action scope of a classical topical solution. This study evaluates the impact of a novel home-use device combining a topical serum, light-emitting diodes and massage on the clinical signs of extrinsic skin aging. The innovative principle relies on potentiating the effect of active ingredients contained in the topical serum with visible and near infra-red photons to prevent extracellular matrix degradation and promote its reconstruction. After in vitro and ex vivo investigations, a clinical study assessed the safety and efficacy of a daily treatment with the home-use device for 28 days. A significant increases in skin density and radiance while reducing the wrinkles was obtained with no side effects.

A simple morphometric analysis method for dermal microstructure using color thresholding and moments

BACKGROUND

Proper assessment of dermal collagen fibers by dermatologists and researchers is essential. Histologic evaluation methods have limitations. We present a simple method for measurement of collagen fibers in human skin using Masson's trichrome staining.

MATERIALS AND METHODS

Normal skin specimens from a cadaver were processed with Masson's trichrome, which can effectively stain collagen fibers blue with aniline dye. Optical photomicrographs of these slides were analyzed using ImageJ software. Color image processing, a histogram-based function of ImageJ for image segmentation, was performed with color moments thresholding technique. We selected blue areas by adjusting the blue channel to include specific values. The selected areas were highlighted and evaluated. We divided the image into layers of 0.09-mm² areas from the top to bottom of the dermis. Each area was cropped and evaluated.

RESULTS

Quantitative assessment yielded the quantitative size occupied by collagen fibers in an area of 0.09 mm² . Calculation of the percentage in each area can be used to determine the density of collagen fibers.

CONCLUSION

Measurements obtained with our method can be applied to research on dermal collagen fibers. We present a convenient quantitative assessment method for the dermal constituents in Masson's trichrome-stained slides.

An updated review of clinical methods in the assessment of ageing skin - New perspectives and evaluation for claims support

With the advancement of skin research, today's consumer has increased access to an informed understanding of ageing skin and its appendages, together with a plethora of targeted products to meet such needs. In recent years, increased legislative demands for quality evidential claims support have led not only to the development and validation of clinical methods to measure and quantify ageing skin, but also a clearer understanding of the skin ageing process-especially the impact of both its internal and external environments-as well as a tougher stance on clearly unjustifiable claims. Traditional testing methods used to research and evaluate anti-ageing products claim to employ sophisticated instruments. Today, however, since the term anti-ageing can be considered a misnomer, intelligent use of combined more advanced clinical methods has enabled the development of technologically improved consumer products providing enhanced efficacy and targeted performance. Non-invasive methods for the assessment and quantification of the causes of ageing skin provide tools to the clinical researcher as defined by key clinically observed ageing parameters. Where evidence requires additional support, a number of clinical procedures evaluating ageing skin and hair products are combined with invasive procedures, thus enabling an added value to product claims. As discussed herein, given the enhanced understanding of ageing, we provide an update to our previous reviews of clinical methods used in the assessment of skin ageing, to include the wider aspects of environmental exposure; skin pigmentation; microbiome disturbance; surface topography; colour, radiance, and pH; and structural integrity-all requiring a disciplined approach to their use in dermatological investigations and product claims evidence.