Age dependence of skin autofluorescence

Abstract

The nontryptophane intrinsic fluorescence of finger pad skin was studied in men aged 20-70 years in order to evaluate the possibility of using this parameter as a biomarker of aging. Linear correlation coefficients (r) between the fluorescence intensity and age varied from 0.50 to 0.66 for various skin sites. Age dependence of the mean value of fluorescence (F) measured on 4 fingers can be approximated by a second-degree polynomial: F=2.82-0.083T+0.0014T 2 (ri=0.64, r2=0.71 ), where T is chronological age in years. The proposed measurement of skin autofluorescence is a simple, noninvasive, rapid test for evaluating the aging or the skin in subjects over 40 with a high age-related determination (r2=0.5). Nontryptophane intrinsic fluorescence (FL) of the skin can be used as a biological marker of aging. Measurements of FL of subcutaneous collagen removed during intervention for vascular diseases showed a high correlation r=-0.99 (n=26) between FL intensity (FLI) and age (42-78 years) [9], the age-standardized FLI did not correlate with sex, weight, or vascular pathology. Study of laser-induced intrinsic FL of the skin at a wavelength 325 nm in skin areas exposed and not exposed to sunlidht showed no correlation with age, but revealed a notable decrease in FLI of exposed skin sites, particularly in elderly subjects [8].The problem is to choose the conditions of FL recording at which skin FL correlates with chronological age. We measured the nontryptophane FL of the skin of finger pads of men aged 20-70 years. MATERIALS AND METHODSSkin FLI was measured in spring (April-May) in 44 healthy men aged 20-70 years. The device Ior measuring human skin FL was based on a Spekol fluorimeter equipped with an element tor measuring FL of solid specimens (recording of FL from the anterior surface through a 5-mm opening) and UFS (at 365 nm excitation) and ZhS-5 filters (emission of more than 420 nm). FLI was measured on the third and fourth fingers of both hands after degreasing with ethanol.The reference was white paper with intrinsic FL in this range. When recording the emission spectra, the FL beam was delivered to the monochromator through an optic fiber.The sampling coefficients of correlations were evaluated using Fisher's z transformations: z=0.5 [ln(l+r)-ln(l+r)], with the lbllowing ratio as the reliability test for z: t~=z(n-3) -~ which, in turn, was compared to the critical t point determined from the critical point tables of Student's test [4]. RESULTS

Laser-induced fluorescence made simple: implications for the diagnosis and follow-up monitoring of basal cell carcinoma

“…13 Also, the interpretation of results may depend on patient-related characteristics such as skin age and phototype. 54,55 In order to account for intrapatient and intralesion variations in the evaluation of the results from LIF spectra, mathematical models and specific statistical analysis techniques have been applied. Some researchers focused on the spectral profile of each spectrum containing specific characteristics that are more consistent.…”