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Background: Establishing a high-accuracy and non-invasive method is essential for evaluating cardiovascular disease. Skin cholesterol is a novel marker for assessing the risk of atherosclerosis and can be used as an independent risk factor of early assessment of atherosclerotic risk., Methods: We propose a non-invasive skin cholesterol detection method based on absorption spectroscopy. Detection reagents specifically bind to skin cholesterol and react with indicator to produce colored products, the skin cholesterol content can be obtained through absorption spectrum information on colored products detected by non-invasive technology. Gas chromatography is used to measure cholesterol extracted from the skin to verify the accuracy and reliability of the non-invasive test method. A total of 342 subjects were divided into normal group (n = 115), disease group (n = 110) and risk group (n = 117). All subjects underwent non-invasive skin cholesterol test. The diagnostic accuracy of the measured value was analyzed by receiver-operating characteristic (ROC) curve., Results: The proposed method is able to identify porcine skin containing gradient concentration of cholesterol. The values measured by non-invasive detection method were significantly correlated with gas chromatography measured results (r = 0.9074, n = 73, p < 0.001). Bland-Altman bias was - 72.78 ± 20.03 with 95% limits of agreement - 112.05 to - 33.51, falling within the prespecified clinically non-significant range. We further evaluated the method of patients with atherosclerosis and risk population as well as normal group, patients and risk atherosclerosis group exhibited higher skin cholesterol content than normal group (all P < 0.001). The area under the ROC curve for distinguishing Normal/Disease group was 0.8642 (95% confidence interval, 0.8138 to 0.9146), meanwhile, the area under the ROC curve for distinguishing Normal/Risk group was 0.8534 (95% confidence interval, 0.8034 to 0.9034)., Conclusions: The method demonstrated its capability of detecting different concentration of skin cholesterol. This non-invasive skin cholesterol detection system may potentially be used as a risk assessment tool for atherosclerosis screening, especially for a large population.

Background: Dynamic orchestration of metabolic pathways during continuous fasting remains unclear.Objective: We investigated the physiological effects of Bigu-style fasting and underlying metabolic reprogramming in healthy adults.Methods: We conducted a 5-d Bigu trial in 43 healthy subjects [age 23.2 ± 2.4 y; BMI (in kg/m2) 22.52 ± 1.79]. Physiological indicators and body composition were monitored daily during fasting day 1 (F1D) to F5D and after 10-d refeeding postfasting (R10D) and R30D. Blood samples were collected in the morning. Risk factors associated with inflammation, aging, cardiovascular diseases, malnutrition, and organ dysfunction were evaluated by biochemical measurements. Untargeted plasma metabolomics and gut microbial profiling were performed using plasma and fecal samples. Data were analyzed by repeated measures ANOVA with Greenhouse-Geisser correction. Correlation analyses for metabolite modules and taurine were analyzed by Spearman's rank and Pearson tests, respectively.Results: Heart rate was accelerated throughout the fasting period. Risk factors associated with inflammation and cardiovascular diseases were significantly lowered during or after Bigu (P < 0.05). Body composition measurement detected an overconsumption of fat starting from F3D till 1 mo after refeeding. Metabolomics unveiled a coupling between gluconeogenesis and cholesterol biosynthesis beyond F3D. Plasma taurine significantly increased at F3D by 31%-46% followed by a reduction to basal level at F5D (P < 0.001), a pattern inversely correlated with changes in glucose and de novo synthesized cholesterol (r = -0.407 and -0.296, respectively; P < 0.001). Gut microbial profiling showed an enrichment of taurine-utilizing bacteria at F5D, which was completely recovered at R10D.Conclusions: Our data demonstrate that 5-d Bigu is potentially beneficial to health in young adults. A starvation threshold of 3-d fasting is necessary for maintaining glucose and cholesterol homeostasis via a taurine-microbiota regulatory loop. Our findings provide novel insights into the physiological and metabolic responses of the human body to continuous Bigu-style fasting. This trial was registered at http://www.chictr.org.cn as ChiCTR1900022917. [ABSTRACT FROM AUTHOR]