Longitudinal in vivo tracking of adverse effects following topical steroid treatment

Abstract

Topical steroids are known for their anti-inflammatory properties and are commonly prescribed to treat many adverse skin conditions such as eczema and psoriasis. While these treatments are known to be effective, adverse effects including skin atrophy are common. In this study, the progression of these effects is investigated in an in vivo mouse model using multimodal optical microscopy. Utilizing a system capable of performing two-photon excitation fluorescence microscopy (TPEF) of reduced nicotinamide adenine dinucleotide (NADH) to visualize the epidermal cell layers and second harmonic generation (SHG) microscopy to identify collagen in the dermis, these processes can be studied at the cellular level. Fluorescence lifetime imaging microscopy (FLIM) is also utilized to image intracellular NADH levels to obtain molecular information regarding metabolic activity following steroid treatment. In this study, fluticasone propionate (FP) treated, mometasone furoate (MF) treated, and untreated animals were imaged longitudinally using a custom-built multimodal optical microscope. Prolonged steroid treatment over the course of 21 days is shown to result in a significant increase in mean fluorescence lifetime of NADH, suggesting a faster rate of maturation of epidermal keratinocytes. Alterations to collagen organization and the structural microenvironment are also observed. These results give insight into the structural and biochemical processes of skin atrophy associated with prolonged steroid treatment.

Vitamin A and Wound Healing

“…Glucocorticoids have multiple treatment indications but also numerous undesirable effects, especially with long‐term use for diseases such as rheumatoid arthritis . Typical skin effects noticed with long‐term systemic and even topical glucocorticoid utilization include atrophy, ecchymosis, and purpura …”

In situ biodistribution and residency of a topical anti‐inflammatory using fluorescence lifetime imaging microscopy

“…This differentiation can be utilized as a marker for metabolic activity. 4 In a previous study investigating the transdermal kinetics of a drug formulation in human skin sections ex vivo, FLIM was used to monitor the drug's diffusion pathway by measuring the variation in bound NAD(P)H fluorescence lifetime before and 2 h after drug application. 5 In addition to NAD(P)H, a variety of additional endogenous fluorophores are also observed in skin.…”

Video-rate multimodal multiphoton imaging and three-dimensional characterization of cellular dynamics in wounded skin

“…12,13 As a tissue component that plays a key role in the pathological state of skin diseases and cancerous tumors, numerous computational methods have been developed to characterize its¯ber structure. [12][13][14][15][16] Some of the collagen parameters that have been investigated include¯ber angle, length, width, density, and curvature. These parameters can also be characterized computationally using mathematical models, such as Fourier analysis, 14 and various computer-assisted image feature extraction methods, including curvelet transform¯ber extraction algorithm (CT-FIRE).…”

“…[12][13][14][15][16] Some of the collagen parameters that have been investigated include¯ber angle, length, width, density, and curvature. These parameters can also be characterized computationally using mathematical models, such as Fourier analysis, 14 and various computer-assisted image feature extraction methods, including curvelet transform¯ber extraction algorithm (CT-FIRE). 13,17,18 Among other techniques, CT-FIRE is especially powerful because it integrates¯ber-based preprocessing techniques with ber extraction methods to improve¯ber extraction accuracy, which leads to high sensitivity to changes in collagen alignment.…”