Which are the main fluorophores in skin and oral mucosa? A review with emphasis on clinical applications of tissue autofluorescence

Abstract

The present review provides information about which molecules appear to be the main fluorophores in skin and oral mucosa, together with their clinical applications. Design: The MEDLINE database was searched, using "oral mucosa AND fluorophores", "skin AND fluorophores", "epidermal AND fluorophores", "dermal AND fluorophores" and "cutaneous AND fluorophores" as entry terms.We searched the literature following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The level of evidence in the studies was assessed using the Classification of the Oxford Centre for Evidence-based Medicine (CEBM) Levels for Diagnosis. Results: Five papers and 17 were primarily focused on description of fluorophores in oral mucosa and skin Evidence exists that fluorophores of oral mucosa and skin are mainly proteins such as collagen, elastin, keratin and tryptophan. Other possible fluorophores identified are: porphyrins, advanced glycation end products, flavins, lipopigment, nicotinamide adenine dinucleotide, flavin adenine dinucleotide, pheomelanin, eumelanin and components of lipofuscin.Clinical applications of oral mucosal autofluorescence (AF) are related to management of malignant and potentially malignant lesions. In the skin, AF has been used for acne assessment, diagnosis of sweat-gland pathologies, glycemic control and management of malignant lesions and as a marker for skin aging. Conclusion: Fluorophores stimulated through AF devices are implied in different physiologic and pathologic processes. AF seems to be useful for several clinical applications, especially in skin department.Because most of the studies show a low level of evidence, further studies are necessary in such a promising and fascinating field.

Optical Biopsy of Amelanotic Melanoma with Raman and Autofluorescence Spectra Stimulated by 785 nm Laser Excitation

“…The spectrum stimulated with 785 nm laser is a nonlinear decreasing autofluorescence curve with broadband maxima (near 870 nm) and narrow Raman peaks in 850-900 nm area. The broadband autofluorescence maxima that are contributed by the endogenous skin fluorophores (mainly melanin, lipids, lipofuscins and others [17]) overlap weak Raman bands especially near 866 nm (1200 cm -1 ) that makes it difficult to register Raman signal in this spectral region, especially in MM analysis. Therefore, Raman bands can be visualized at wavenumbers between 1200 and 1800 cm -1 .…”

Effect of tobacco in human oral leukoplakia: a cytomorphometric analysis

“…The cellular changes occur at the molecular level during the transformation of healthy tissue to premalignancy or malignancy, before they are seen under the microscope and much before clinical changes become evident. Identification of high-risk oral premalignant lesions and intervention at premalignant stages can play an important key role in reducing mortality, morbidity and cost of oral squamous cell carcinoma associated treatment [40].…”

Autofluorescence Imaging of the Skin Is an Objective Non-Invasive Technique for Diagnosing Pseudoxanthoma Elasticum

“…The mineralization of elastin fibers and alterations of the collagen structure are also histopathological features of PXE [21]. Therefore, in addition to calcium compounds, elastin and collagen as endogenous fluorophores could also be responsible for the increased AF signal [45]. Additional studies would be necessary to clarify the exact origin of high AF signal in PXE lesions under 405 nm excitation.…”