In vivo detection of changes in cutaneous carotenoids after chemotherapy using shifted excitation resonance Raman difference and fluorescence spectroscopy

In vivo Raman spectroscopic and fluorescence study of suspected melanocytic lesions and surrounding healthy skin

Cutaneous melanoma is the most lethal skin cancer and noninvasively distinguishing it from benign tumor is a major challenge. Raman spectroscopic measurements were conducted on 65 suspected melanocytic lesions and surrounding healthy skin from 47 patients. Compared to the spectra of healthy skin, spectra of melanocytic lesions exhibited lower intensities in carotenoid bands and higher intensities in lipid and melanin bands, suggesting similar variations in the content of these components. Distinct variations were observed among the autofluorescence intensities of healthy skin, benign nevi and malignant melanoma. By incorporating autofluorescence information, the classification accuracy of the support vector machine for spectra of healthy skin, nevi, and melanoma reached 90.2%, surpassing the 87.9% accuracy achieved without autofluorescence, with this difference being statistically significant. These findings indicate the diagnostic value of autofluorescence intensity, which reflect differences in fluorophore content, chemical composition, and structure among healthy skin, nevi, and melanoma.

Lycopene, but not zeaxanthin, serves as a skeleton for the formation of an orthorhombic organization of intercellular lipids within the lamellae in the stratum corneum: Molecular dynamics simulations of the hydrated ceramide NS bilayer model

Carotenoids play an important role in the protection of biomembranes against oxidative damage. Their function depends on the surroundings and the organization of the lipid membrane they are embedded in. Carotenoids are located parallel or perpendicular to the surface of the lipid bilayer. The influence of carotenoids on the organization of the lipid bilayer in the stratum corneum has not been thoroughly considered. Here, the orientation of the exemplary cutaneous carotenoids lycopene and zeaxanthin in a hydrated ceramide NS24 bilayer model and the influence of carotenoids on the lateral organization of the lipid bilayer model were studied by means of molecular dynamics simulations for 32 °C and 37 °C. The results confirm that lycopene is located parallel and zeaxanthin perpendicular to the surface of the lipid bilayer. The lycopene-loaded lipid bilayer appeared to have a strong orthorhombic organization, while zeaxanthin-loaded and pure lipid bilayers were organized in a disordered hexagonal-like and liquid-like state, respectively. The effect is stronger at 32 °C compared to 37 °C based on p-values. Therefore, it was assumed that carotenoids without hydroxyl polar groups in their structure facilitate the formation of the orthorhombic organization of lipids, which provides the skin barrier function. It was shown that the distance between carotenoid atoms matched the distance between atoms in the lipids, indicating that parallel located carotenoids without hydroxyl groups serve as a skeleton for lipid membranes inside the lamellae. The obtained results provide reasonable prediction of the overall qualitative properties of lipid model systems and show the importance of parallel-oriented carotenoids in the development and maintenance of the skin barrier function.

Carotenoids in Human SkinIn Vivo: Antioxidant and Photo-Protectant Role against External and Internal Stressors

The antioxidant system of the human body plays a crucial role in maintaining redox homeostasis and has an important protective function. Carotenoids have pronounced antioxidant properties in the neutralization of free radicals. In human skin, carotenoids have a high concentration in the stratum corneum (SC)-the horny outermost layer of the epidermis, where they accumulate within lipid lamellae. Resonance Raman spectroscopy and diffuse reflectance spectroscopy are optical methods that are used to non-invasively determine the carotenoid concentration in the human SC in vivo. It was shown by electron paramagnetic resonance spectroscopy that carotenoids support the entire antioxidant status of the human SC in vivo by neutralizing free radicals and thus, counteracting the development of oxidative stress. This review is devoted to assembling the kinetics of the carotenoids in the human SC in vivo using non-invasive optical and spectroscopic methods. Factors contributing to the changes of the carotenoid concentration in the human SC and their influence on the antioxidant status of the SC in vivo are summarized. The effect of chemotherapy on the carotenoid concentration of the SC in cancer patients is presented. A potential antioxidant-based pathomechanism of chemotherapy-induced hand-foot syndrome and a method to reduce its frequency and severity are discussed.

Kinetics of the carotenoid concentration degradation of smoothies and their influence on the antioxidant status of the human skin in vivo during 8 weeks of daily consumption

The antioxidant status of the skin shows constant alterations depending on nutrition and other lifestyle factors. Carotenoids can serve as marker substances for the antioxidant status of the epidermis in vivo. The carotenoid concentration of 2 homemade green smoothies and a commercial green smoothie, all containing fruits and vegetables, was assessed by resonance Raman spectroscopy. Furthermore, a pilot study was conducted to investigate changes of the cutaneous carotenoid concentration of 20 healthy volunteers under the daily intake of either a homemade smoothie or the commercial smoothie in vivo using reflectance spectroscopy. We hypothesized that higher carotenoid concentrations in the homemade smoothies compared to those of the commercial one would lead to a faster increase of the cutaneous carotenoid concentration in healthy volunteers. The measurements of the homemade smoothies showed notably higher initial carotenoid concentrations (7.6 ±0.8)*10^-4arbitrary units (a.u.) (smoothie A) and (10.4 ± 0.6)*10^-4 a.u. (smoothie B) compared to the commercial smoothie (5.8 ± 0.2)*10^-4 a.u. Nevertheless, the commercial smoothie showed a higher stability of carotenoids over 24 hours. 8 weeks after daily consumption of the homemade smoothies, volunteers showed an insignificant increase of cutaneous carotenoids from (4.5 ± 0.1)*10^-4 a.u. at baseline to (4.8 ± 0.3)*10^-4 a.u. (means ± standard error of the mean). The volunteers consuming the commercial smoothie showed an insignificant increase of cutaneous carotenoids from (4.3 ± 0.2)*10^-4 a.u. to (4.7 ± 0.2)*10^-4 a.u. after 8 weeks. The observed increase of cutaneous carotenoid concentrations could be classified as a strong tendency. Fresh homemade smoothies can exhibit a higher carotenoid concentration compared to commercial smoothies but need to be consumed immediately after preparation.