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Query: "author" (Alessio Nunnari) .

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1.
Initial glutathione depletion during short-term bed rest : pinpointing synthesis and degradation checkpoints in the γ-glutamyl cycle
Filippo Giorgio Di Girolamo, Filippo Mearelli, Mariella Sturma, Nicola Fiotti, Kaja Teraž, Alja Ivetac, Alessio Nunnari, Pierandrea Vinci, Boštjan Šimunič, Rado Pišot, Gianni Biolo, 2024, original scientific article

Abstract: Hypokinesia triggers oxidative stress and accelerates the turnover of the glutathione system via the γ-glutamyl cycle. Our study aimed to identify the regulatory checkpoints controlling intracellular glutathione levels. We measured the intermediate substrates of the γ-glutamyl cycle in erythrocytes from 19 healthy young male volunteers before and during a 10-day experimental bed rest. Additionally, we tracked changes in glutathione levels and specific metabolite ratios up to 21 days of bed rest. Using gas chromatography-mass spectrometry and the internal standard technique, we observed a 9 ± 9% decrease in glutathione levels during the first 5 days of bed rest, followed by an 11 ± 9% increase from the 5th to the 10th day, nearly returning to baseline ambulatory levels. The cysteinyl-glycine-to-glutathione ratio, reflecting γ-glutamyl cyclotransferase activity (a key enzyme in glutathione breakdown), rose by 14 ± 22% in the first 5 days and then fell by 10 ± 14% over the subsequent 5 days, again approaching baseline levels. Additionally, the γ-glutamyl cysteine-to-cysteine ratio, indicative of γ-glutamyl cysteine synthetase activity (crucial for glutathione synthesis), increased by 12 ± 30% on day 5 and by 29 ± 41% on day 10 of bed rest. The results observed on day 21 of bed rest confirm those seen on day 10. By calculating the ratio of product concentration to precursor concentration, we assessed the efficiency of these key enzymes in glutathione turnover. These results were corroborated by directly measuring glutathione synthesis and degradation rates in vivo using stable isotope techniques. Our findings reveal significant changes in glutathione kinetics during the initial days of bed rest and identify potential therapeutic targets for maintaining glutathione levels.
Keywords: antioxidant, muscle unloading, glutathion turnover, γ-glutamyl cycle, gamma-glutamyl cycle
Published in DiRROS: 21.11.2024; Views: 819; Downloads: 1574
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2.
The abdominal adiposity index (a body shape index) predicts 10-year all-cause mortality in elderly active non-obese subjects
Alessio Nunnari, Filippo Giorgio Di Girolamo, Kaja Teraž, Nicola Fiotti, Boštjan Šimunič, Filippo Mearelli, Rado Pišot, Gianni Biolo, 2024, original scientific article

Abstract: Background/Objectives: A Body Shape Index (ABSI), which accounts for waist circumference relative to mass and height, shows a robust association with mortality risk. The present study evaluates the effectiveness of ABSI as a predictor of 10-year all-cause mortality in physically active, non-obese elderly individuals. Methods: This prospective cohort study included 159 volunteers (94 women, aged 60–80 years), recruited in the frame of the “Physical Activity and Nutrition for Great Ageing” (PANGeA) Cross-border Cooperation Program Slovenia–Italy 2007–2013, and followed for 10 years. Baseline characteristics included anthropometric measurements, bioelectrical impedance analysis, and cardiovascular fitness tests (VO2max). Statistical analyses (Cox regression, Kaplan–Meier survival) were conducted to examine the relationship between ABSI and mortality. Results: During the 10-year follow-up, 10 deaths (6.7%) were recorded. ABSI (adjusted for age, smoking, comorbidities, and therapy) was an independent predictor of mortality (hazard ratio = 4.65, p < 0.001). Higher ABSI scores were linked to reduced VO2max (r = −0.190, p = 0.017) and increased systolic blood pressure (r = 0.262, p = 0.001). An ABSI-based predictive model showed strong discriminatory power (AUROC = 0.91). Conclusions: ABSI is a reliable predictor of 10-year mortality in active, non-obese elderly individuals and may improve risk stratification in clinical practice.
Keywords: ABSI, a body shape index, body shape, fre fat mass, sarcopenia, prognostic index, elderly, mortality
Published in DiRROS: 16.10.2024; Views: 1004; Downloads: 706
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