Concentration of FAD as a marker for cervical precancer detection

Abstract

We report the ex vivo results of an in-house fabricated portable device based on polarized fluorescence measurements in the clinical environment. This device measures the polarized fluorescence and elastic scattering spectra with 405-nm laser and white light sources, respectively. The dominating fluorophore with 405-nm excitation is flavin adenine dinucleotide (FAD) with a fluorescence peak around 510 nm. The measured spectra are highly modulated by the interplay of scattering and absorption effects. Due to this, valuable information gets masked. To reduce these effects, intrinsic fluorescence was extracted by normalizing polarized fluorescence spectra with polarized elastic scattering spectra obtained. A number of fluorophores contribute to the fluorescence spectra and need to be decoupled to understand their roles in the progression of cancer. Nelder-Mead method has been utilized to fit the spectral profile with Gaussian to decouple the different bands of contributing fluorophores (FAD and porphyrin). The change in concentration of FAD during disease progression manifests in the change in ratio of total area to FWHM of its Gaussian profile. Receiver operating characteristic (ROC) curve analysis has been used to discriminate different grades of cervical precancer by using the ratio as input parameter. The sensitivity and specificity for discrimination of normal samples from CIN I (cervical intraepithelial neoplasia) are 75% and 54%, respectively. Further, the normal samples can be discriminated from CIN II samples with 100% and 82% sensitivity and specificity, respectively, and the CIN I from CIN II samples can also be discriminated with 100% sensitivity and 90% specificity, respectively. The results show that the change in the concentration of (FAD) can be used as a marker to discriminate the different grades of the cancer and biochemical changes at an early stage of the cancer can also be monitored with this technique.

Comparative study of in‐vitro autofluorescence of normal versus non‐melanoma‐skin‐cancer cells at different excitation wavelengths

“…While NAD(P)H is luminescent in the reduced state, flavins are luminescent in the oxidized state. The conversion of FAD to its reduced form has been previously reported during cancer progression in vivo [18], which results in luminescence reduction. On the other hand, NAD(P)H oxidation typically occurs in neoplastic cells with increased metabolism, due to its involvement in ATP and energy production [1, 22].…”

“…In Figure 3B the AF spectrum excited with photons at λ exc = 310 nm, where spectral features appear more evident, has been decomposed with multiple Gaussian peaks in a least-squares fitting. Major contributions in normal cells can be associated to characteristic luminescence from coenzymes nicotinamide adenine dinucleotide (phosphate) NAD(P)H, centered at about 440 nm, and flavin-adenin dinucleotide (FAD), at about 530 nm, which can be influenced by metabolic alterations [1,2,12,18]; higher wavelength structures can be associated to lipo-pigments, with maximum at 580 nm, and to porphyrins, at 650 nm and above 700 nm [19]. It is important to notice that all contributions are strongly depressed in the cancerous cells.…”

Laser induced fluorescence spectroscopy analysis of kidney tissues: A pilot study for the identification of renal cell carcinoma

“…The signature of FAD (emission at 545 nm) is higher in case of ccRCC compared to chRCC. This can be attributed to the dominance of glycolysis over oxidative phosphorylation in ccRCC [42]. Further, the lactate dehydrogenase assay(LDH) assay was performed to ensure the high glycolysis in ccRCC in comparison with ChRCC and normal renal tissue.…”

Noninvasive detection of diabetes mellitus based on skin fluorescence and diffuse reflectance spectroscopy

“…The skin‐measured fluorescence spectrum contained different fluorescent fluorophores information, and the composition of the shoulder peak was not obvious at this time, Gaussian multi‐peak fitting decomposition method can effectively separate and analyze the original superimposed fluorescence spectrum of the skin tissue. Meena et al developed a portable fluorescence detection device (excitation light 405 nm) [34]. The Gaussian fitting was used to decompose the tissue fluorescence, and the detection of FAD and porphyrin was realized.…”