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.

Detection of skin alterations in mild-to-moderate chronic venous disease using non-invasive techniques.

BACKGROUND: Chronic venous disease (CVD) is secondary to venous hypertension, leading to vascular inflammation and tissue changes. The impact of CVD on skin structure and barrier function is not well characterized. OBJECTIVE: We aimed to assess the characteristics of skin alterations in mild-to-moderate CVD by non-invasive techniques based on a prospective exploratory study. MATERIAL & METHODS: Female subjects (30-75 years) with CVD (Stage C2 to C4, CEAP classification) were eligible. Stage C0-C1 CVD subjects were used as controls. Women with leg surgery or a medical history that could impact the results were excluded. The skin changes on lesional (LS) and non-lesional (NLS) areas were assessed by biometric analysis including skin echography, viscoelasticity evaluation, confocal microscopy and trans epidermal water loss (TEWL) measurements. RESULTS: Thirty-four subjects were enrolled. Based on computation of 26 biometric parameters using Principal Component Analysis, a significant difference between LS and NLS zones, regardless of the CEAP class, was evidenced. C2-C4 subjects presented with dermal thickening suggesting oedema associated with decreased cell density, while no difference in skin viscoelasticity was observed compared to the C0-C1 control group. Epidermal structural modifications were associated with increased TEWL correlating with CVD severity. CONCLUSION: Skin alterations in CVD patients are detectable by non-invasive methods. These findings may help to better assess new therapeutic strategies.