Non‐invasive evaluation of dermal elastosis by in vivo multiphoton tomography with autofluorescence lifetime measurements

Abstract

The non-invasive differentiation of dermal elastic fibres from solar elastosis in vivo is of great interest in dermatologic research, especially for efficacy testing of anti-ageing products. To date, no studies on multiphoton excited fluorescence lifetime characteristics of human elastic fibres and solar elastosis are reported. The goal of the present work was the identification of differential criteria for elastic fibres and solar elastosis by the analysis of fluorescence decay curves acquired by time-correlated single photon counting in vivo multiphoton tomography. For this purpose, fluorescence lifetime measurements (FLIM) were performed with 47 volunteers of different age groups at sun-protected and sun-exposed localizations. Bi-exponential curve fitting was applied to the FLIM data, and characteristic differences between age groups and localizations were found in both relevant fit parameters describing the decay slope. The FLIM analyses have shown that dermal autofluorescence has different lifetimes depending on age and in part on localization.

Two-photon autofluorescence lifetime imaging of human skin papillary dermis in vivo: assessment of blood capillaries and structural proteins localization

“…67 reported the differences in lifetime distributions for the dermis obtained using MPT depending on the patients’ age and skin area localization (sun-protected or sun-exposed), that was attributed to different content of collagen I and elastin. However, this research investigated neither spatial lifetime distribution nor attribution of lifetimes to certain fluorophores.…”

A quantitative approach to histopathological dissection of elastin-related disorders using multiphoton microscopy

“…DermaInspect â and MPTflex â ; JenLab GmbH, Jena, Germany) to investigate the structural composition of human skin and disease processes both ex vivo (burns scars, scleroderma, fungal skin infections, nonmelanoma skin cancers and anetoderma) [8][9][10][11][12] and in vivo (chronological ageing and photoageing, scars, inflammatory and bullous skin conditions, and premalignant and malignant skin tumours). [13][14][15][16][17][18] The technology also extends to more functional measurements in drug delivery research and the efficacy of antiageing products. [19][20][21] In this study, we have utilized the capacity of MPM to highlight elastic fibres within the dermis.…”

“…14,16,17,26,27 Other similar measures include the SHG to TPEF index of the dermis, 11 the Dermis Morphology Score 13 and the more recently described elastin-to-collagen ratio. 15 Although histological studies have measured the relative content of elastin in rare elastin disorders, as well as in photoaged and chronologically aged skin, no study has attempted to quantify with MPM the absolute elastin content in the setting of solar elastosis. normal elastic fibres can be distinguished from solar elastosis.…”

Non‐invasive objective devices for monitoring the inflammatory, proliferative and remodelling phases of cutaneous wound healing and skin scarring

“…Additionally, multiphoton excited fluorescence lifetime characteristics of human elastic fibres have been studied. Fluorescence lifetime measurements (FLIM) were performed with 47 volunteers of different age groups at sun‐protected and sun‐exposed localisations , and this method proved to be useful in this analysis.…”