COLLAGEN AS IN VIVO QUANTITATIVE FLUORESCENT BIOMARKERS OF ABNORMAL TISSUE CHANGES

Abstract

Collagen is an endogenous fluorophore that accounts for about 70% of all proteins of human skin, so it can be an optical marker for structural abnormalities in tissues registered by laser fluorescent diagnostics in vivo. Using the examples of such abnormalities as scars, scleroderma and basal cell carcinoma, this study shows the differences between coefficients of fluorescent contrast kf(λ) of abnormalities from the ones for healthy tissues at fluorescent excitation wavelength 360–380 nm. It is shown that scars and dysplasia are characterized by reduced values of kf(λ) for collagen. Due to high turbidity and phase heterogeneousness as well as variation of parameters of blood microcirculation and concentrations of other related chromophores, there is no mathematical model that precisely calculates the concentration of collagen in tissues only with the use of the value of fluorescent signal intensity. So, probably, the best marker of the pathological process is a comprehensive representation of kf(λ) for all endogenous fluorophores, i.e., for all used visible wavelengths. In this case identification of abnormal tissues is quite possible by detecting some deviations of coefficients kf(λ) for the optically identical and symmetrical regions of the human body.

Simultaneous characterization of pancreatic stellate cells and other pancreatic components within three-dimensional tissue environment during chronic pancreatitis

“…16,22,23 Using this method, stromal collagen, which is the major source of SHG signals in extracellular matrix, has been recognized from cellular components. [24][25][26] Lymphatic cells have been distinguished from the other gastric tissue types due to a broad emission that possibly originates from phospholipids, known to be a significant component of lymphocytes. 16 Besides, morphological characteristics obtained by nonlinear optical microscopy can also provide information relating to the differentiation of multiple cell types.…”

Optical redox ratio and endogenous porphyrins in the detection of urinary bladder cancer: A patient biopsy analysis

“…Sample spectra were exported as ASCII files and combined, plotted and visualised using Origin Pro 8 analysis software. From the custom‐made LDF3.1 software, amplitudes of fluorescence for specific fluorophores of interest were recorded, in keeping with previous work by Dunaev et al , Akbar et al and Smirnova et al . The excitation and emission wavelengths for the endogenous fluorophores of interest were as follows (Table ).…”

In vivo noninvasive measurement of skin autofluorescence biomarkers relate to cardiovascular disease in mice

“…SAF were used in the ultra-violet spectra through insertion of a spectral density filter for measurement of collagen, elastin, nicotinamide adenine dinucleotide (NADH), lipofuscin, pyridoxine, β-carotene and flavins. Wavelengths for the aforementioned biomarkers have previously been described using the LAKK-M system elsewhere (Smirnova et al, 2012;Rogatkin et al, 2013). The peak emission wavelengths used for the measurement of these compounds are as described in Table 1.…”