Bénéfice longévité du thé vert ?

[Nutrimuscle-Conseils]

Oral administration of EGCG solution equivalent to daily achievable dosages of regular tea drinkers effectively suppresses miR483-3p induced metastasis of hepatocellular carcinoma cells in mice
Food & Function 2021, Volume 12, Issue 8 Qingzheng Kang

The effect of non-cytotoxic doses of epigallocatechin-3-gallate (EGCG) on the metastatic capability of human hepatocellular carcinoma (HCC) cells was investigated in vitro and in vivo. miR483-3p, a microRNA whose expression correlates inversely with survival and positively with disease progression in HCC patients, was found to promote HCC cell migration and invasion in vitro as well as lung metastasis in nude mice established by the tail-vein injection of HCC cells. The induction of reactive oxygen species (ROS) and downregulation of antioxidant defense factors Nrf2 and SOD2 appeared to be an important underlying mechanism and treatment with a non-cytotoxic dose of EGCG effectively reversed the miR483-3p-induced enhancement of HCC cell migration and invasion in vitro. Moreover, administration through drinking water at doses (0.1% and 0.5% EGCG solution, respectively) equivalent to the intake of regular to heavy tea drinkers could also significantly inhibit lung metastasis of HCC cells based on the estimation from the USDA Database for the Flavonoid Content of Selected Foods and FDA guidelines for the conversion of animal dose to human equivalent dose. EGCG also significantly counteracted the miR483-3p-induced alteration in the expression of epithelial–mesenchymal transition (EMT) markers, E-cadherin and vimentin, and downregulated the endogenous expression of miR483-3p in HCC cells through an epigenetic mechanism that led to the hypermethylation of the miR483-3p promoter region.

The data from our study illustrate that miR483-3p promotes HCC metastasis likely through the induction of oxidative stress and uncover a novel role of EGCG for protection against miR483-3p-mediated HCC metastasis via the epigenetic modulation of miR483-3p expression.

These findings therefore provide further evidence supporting that regular tea consumption may contribute to protection against miR-483-3p-induced ROS and the associated HCC progression.

[Nutrimuscle-Conseils]

Stimulatory effects of (−)-epicatechin and its enantiomer (+)-epicatechin on mouse frontal cortex neurogenesis markers and short-term memory: proof of concept
Viridiana Navarrete-Yañez, Food & Function 2021, Volume 12, Issue 8

Consumption of (−)-epicatechin (Epi), a cacao flavanol improves cognition. The aim was to compare the effects of (−)-Epi or its stereoisomer (+)-Epi on mouse frontal cortex-dependent short-term working memory and modulators of neurogenesis. Three-month-old male mice (n = 7 per group) were provided by gavage either water (vehicle; Veh), (−)-Epi, at 1 mg kg−1 or (+)-Epi at 0.1 mg per kg of body weight for 15 days. After treatment, spontaneous alternation was evaluated by Y-maze. Brain frontal cortex was isolated for nitrate/nitrite measurements, Western blotting for nerve growth factor (NGF), microtubule associated protein 2 (MAP2), endothelial and neuronal nitric oxide synthase (eNOS and nNOS) and immunohistochemistry for neuronal specific protein (NeuN), doublecortin (DCX), capillary (CD31) and neurofilaments (NF200). Results demonstrate the stimulatory capacity of (−)-Epi and (+)-Epi on markers of neuronal proliferation as per increases in immunoreactive cells for NeuN (74 and 120% respectively), DCX (70 and 124%) as well as in NGF (34.4, 63.6%) and MAP2 (41.8, 63.8%). Capillary density yielded significant increases with (−)-Epi (∼80%) vs. (+)-Epi (∼160%). CD31 protein levels increased with (−)-Epi (∼70%) and (+)-Epi (∼140%). Effects correlated with nitrate/nitrite stimulation by (–)-Epi and (+)-Epi (110.2, 246.5%) and enhanced eNOS phosphorylation (Ser1177) with (–)-Epi and (+)-Epi (21.4, 41.2%) while nNOS phosphorylation only increased with (+)-Epi (18%). Neurofilament staining was increased in (–)-Epi by 135.6 and 84% with (+)-Epi. NF200 increased with (–)-Epi (116%) vs. (+)-Epi (84.5%). Frontal cortex-dependent short-term spatial working improved with (–)-Epi and (+)-Epi (15, 13%).

In conclusion, results suggest that both enantiomers, but more effectively (+)-Epi, upregulate neurogenesis markers likely through stimulation of capillary formation and NO triggering, improvements in memory.

[Nutrimuscle-Diététique]

Traduction de l'étude

Effets stimulants de (-) - épicatéchine et son énantiomère (+) - épicatéchine sur les marqueurs de neurogenèse du cortex frontal de souris et la mémoire à court terme: preuve de concept
Viridiana Navarrete-Yañez, Alimentation et fonction 2021, volume 12, numéro 8

La consommation de (-) - épicatéchine (Epi), un flavanol de cacao améliore la cognition. L'objectif était de comparer les effets de (-) - Epi ou de son stéréoisomère (+) - Epi sur la mémoire de travail à court terme dépendant du cortex frontal de souris et les modulateurs de la neurogenèse. Des souris mâles de trois mois (n = 7 par groupe) ont été fournies par gavage soit de l'eau (véhicule; Veh), (-) - Epi, à 1 mg kg − 1 ou (+) - Epi à 0,1 mg par kg de poids corporel pendant 15 jours. Après traitement, l'alternance spontanée a été évaluée par Y-labyrinthe. Le cortex frontal cérébral a été isolé pour les mesures de nitrate / nitrite, le transfert de Western pour le facteur de croissance nerveuse (NGF), la protéine 2 associée aux microtubules (MAP2), l'oxyde nitrique synthase endothéliale et neuronale (eNOS et nNOS) et l'immunohistochimie pour la protéine neuronale spécifique (NeuN), doublécortine (DCX), capillaire (CD31) et neurofilaments (NF200). Les résultats démontrent la capacité stimulante de (-) - Epi et (+) - Epi sur les marqueurs de prolifération neuronale selon l'augmentation des cellules immunoréactives pour NeuN (74 et 120% respectivement), DCX (70 et 124%) ainsi que dans NGF (34,4, 63,6%) et MAP2 (41,8, 63,8%). La densité capillaire a donné des augmentations significatives avec (-) - Epi (80%) vs (+) - Epi (∼160%). Les niveaux de protéine CD31 ont augmenté avec (-) - Epi (∼70%) et (+) - Epi (∼140%). Effets corrélés à la stimulation nitrate / nitrite par (-) - Epi et (+) - Epi (110,2, 246,5%) et augmentation de la phosphorylation de l'eNOS (Ser1177) avec (-) - Epi et (+) - Epi (21,4, 41,2%) tandis que la phosphorylation de nNOS n'a augmenté qu'avec (+) - Epi (18%). La coloration des neurofilaments a été augmentée dans (-) - Epi de 135,6 et 84% avec (+) - Epi. NF200 a augmenté avec (-) - Epi (116%) vs (+) - Epi (84,5%). Travail spatial à court terme dépendant du cortex frontal amélioré avec (-) - Epi et (+) - Epi (15, 13%).

En conclusion, les résultats suggèrent que les deux énantiomères, mais plus efficacement (+) - Epi, régulent à la hausse les marqueurs de la neurogenèse probablement par la stimulation de la formation capillaire et le déclenchement de NO, des améliorations de la mémoire.