Vitis vinifera L. cv. Falanghina Seed Extracts: Antioxidant Effect of Bioactive Compounds on HepG2 Cells.

Vitis vinifera L. is a natural source of bioactive compounds that is already used for cosmeceutical and nutraceutical approaches. However, their phytochemical and antioxidant properties, although studied, have not been fully explored. We aimed to characterize V. vinifera L. cv. Falanghina seed extracts in different polarity solvents (hexane, ethyl acetate, ethanol, and a mixture of acetone-water) for their phytochemical contents, including the total phenolic compound content (TPC), free radical scavenging capacities, and antioxidant ability on HepG2 cells. We directly profiled the functional quality of V. vinifera seed extracts against H2O2-induced oxidative stress in HepG2 cells, focusing on mitochondrial functions. The content of bioactive compounds was characterized by LC-MS. To assess the cytocompatibility of the extracts, a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was conducted. Results showed that extraction with ethyl acetate (18.12 mg GAE·g-1) and ethanol solvents (18.07 mg GAE·g-1), through Soxhlet, and with an acetone-water mixture (14.17 mg GAE·g-1), through maceration, yielded extracts rich in (poly)phenols, with good scavenging and antioxidant activity (98.32 I% for ethanol solvents and 96.31 I% for acetone-water mixture). The antioxidant effect of polyphenols is at least partially due to their capacity to maintain mitochondrial biogenesis and mitophagy, which elevates mitochondrial efficiency, resulting in diminished ROS production, hence re-establishing the mitochondrial quality control. These findings highlight the valorization of Vitis by-products to improve food functional characteristics.

Pax8 and Nkx2-1 haploinsufficiencies differentially affect liver metabolic pathways.

Thyroid dysfunctions are associated with liver diseases ranging, in severity, from insulin resistance (IR) to hepatocellular carcinoma. The pathogenic mechanisms appear complex and are not attributable, exclusively, to the impaired thyroid hormone (TH) signalling. Using a mouse model of human congenital hypothyroidism, young double heterozygote for both NK2 homeobox 1 (Nkx2-1)- and Paired box 8 (Pax8)-null mutations (DHTP) mice, and single heterozygous Pax8+/- and Nkx2-1+/- mice, we studied the liver pathways, the endocrine and metabolic factors affected in conditions of different dysthyroidisms. Young Nkx2-1+/- females displayed a slight hyperthyroidism and, in liver, increased TH signalling (i.e. increased expression of Dio1 and Trß1) and lipogenic gene expression, with triglycerides accumulation. Hypothyroid DHTP and euthyroid Pax8+/- females shared liver and skeletal muscle IR and hepatic hypothyroidism (i.e. reduced expression of Mct8, Dio1 and TRß1), activation of AKT and increased expression of glutathione peroxidase 4. Oxidative stress and reduced mitochondrial COX activity were observed in DHTP mice only. Pax8+/- females, but, unexpectedly, not DHTP ones, displayed transcriptional activation of the hepatic (and renal) gluconeogenic pathway, hypercortisolemia, fasting hyperglycaemia and hyperinsulinemia, reduced serum ß-hydroxybutyrate, associated with hepatic AMPK activation. DHTP mice showed hypercholesterolemia and activation of mTOR. Collectively, the data indicate that heterozygote mutations of Pax8 and Nkx2-1 genes may produce multiple dysmetabolisms, even under systemic euthyroidism. Differential liver pathways and multiple hormonal axes are affected with implications for energy and nutrient homeostasis. The identified players may be specific target in the management of thyroid dysfunction-associated dysmetabolisms in terms of prevention/counteraction of IR, type 2 diabetes and related comorbidities.

Exercise with food withdrawal at thermoneutrality impacts fuel use, the microbiome, AMPK phosphorylation, muscle fibers, and thyroid hormone levels in rats.

Exercise under fasting conditions induces a switch to lipid metabolism, eliciting beneficial metabolic effects. Knowledge of signaling responses underlying metabolic adjustments in such conditions may help to identify therapeutic strategies. Therefore, we studied the effect of mild exercise on rats submitted to food withdrawal at thermoneutrality (28°C) for 3 days. Animals were housed at thermoneutrality rather than the standard housing temperature (22°C) to avoid beta-adrenergic signaling responses that themselves affect metabolism and well-being. Quantitative analysis of multi-organ mRNA levels, myofibers, and serum metabolites shows that this protocol (a) boosts fat oxidation in muscle and liver, (b) reduces lipogenesis and increases gluconeogenesis in liver, (c) increases serum acylcarnitines (especially C4 OH) and ketone bodies and the use of the latter as fuel in muscle, (d) increases Type I myofibers, and (e) is associated with an increased thyroid hormone uptake and metabolism in muscle. In addition, stool microbiome DNA analysis revealed that food withdrawal dramatically alters the presence of bacterial genera associated with ketone metabolism. Taken together, this protocol induces a drastic switch toward increased lipid and ketone metabolism compared to exercise or food withdrawal alone, which may prove beneficial and may involve local thyroid hormones, which may be regarded as exercise mimetics.