The Nutraceutic Silybin Counteracts Excess Lipid Accumulation and Ongoing Oxidative Stress in an In Vitro Model of Non-Alcoholic Fatty Liver Disease Progression

Abstract

Non-alcoholic fatty liver disease (NAFLD) is a major cause of liver-related morbidity and mortality. Oxidative stress and release of pro-inflammatory cytokines, such as tumor necrosis factor α (TNFα), are major consequences of hepatic lipid overload, which can contribute to progression of NAFLD to non-alcoholic steatohepatitis (NASH). Also, mitochondria are involved in the NAFLD pathogenesis for their role in hepatic lipid metabolism. Definitive treatments for NAFLD/NASH are lacking so far. Silybin, the extract of the milk thistle seeds, has previously shown beneficial effects in NAFLD. Sequential exposure of hepatocytes to high concentrations of fatty acids (FAs) and TNFα resulted in fat overload and oxidative stress, which mimic in vitro the progression of NAFLD from simple steatosis (SS) to steatohepatitis (SH). The exposure to 50 µM silybin for 24 h reduced fat accumulation in the model of NAFLD progression. The in vitro progression of NAFLD from SS to SH resulted in reduced hepatocyte viability, increased apoptosis and oxidative stress, reduction in lipid droplet size, and up-regulation of IκB kinase β-interacting protein and adipose triglyceride lipase expressions. The direct action of silybin on SS or SH cells and the underlying mechanisms were assessed. Beneficial action of silybin was sustained by changes in expression/activity of peroxisome proliferator-activated receptors and enzymes for FA oxidation. Moreover, silybin counteracted the FA-induced mitochondrial damage by acting on complementary pathways: (i) increased the mitochondrial size and improved the mitochondrial cristae organization; (ii) stimulated mitochondrial FA oxidation; (iii) reduced basal and maximal respiration and ATP production in SH cells; (iv) stimulated ATP production in SS cells; and (v) rescued the FA-induced apoptotic signals and oxidative stress in SH cells. We provide new insights about the direct protective effects of the nutraceutic silybin on hepatocytes mimicking in vitro NAFLD progression.

Mitochondria and Reactive Oxygen Species in Aging and Age-Related Diseases

“…Several damages were observed at a mitochondrial level and elsewhere in the hepatocyte (reduced hepatocyte viability, increased apoptosis and oxidative stress, reduction in lipid droplet size, and up-regulation of I-κB kinase-interacting protein and adipose triglyceride lipase expressions). Notably silybin, the extract of the milk thistle seeds counteracted the FA-induced mitochondrial damage, increased the mitochondrial size and improved the mitochondrial cristae organization; stimulated mitochondrial FA oxidation; reduced basal and maximal respiration and ATP production in steatohepatitis hepatocytes; stimulated ATP production in steatotic cells, and rescued the FA-induced apoptotic signals and oxidative stress in steatohepatitis hepatocytes (Vecchione et al, 2017). In steatotic livers, ROS formation is increased at the mitochondrial respiratory chain level and determines oxidation of unsaturated lipids (Grattagliano et al, 2008;Grattagliano et al, 2003;Yang et al, 2000).…”

Nobiletin alleviates palmitic acid‑induced NLRP3 inflammasome activation in a sirtuin 1‑dependent manner in AML‑12 cells

“…For instance, baicalin, a flavonoid obtained from Scutellaria baicalensis Georgi, has been demonstrated to have significant anti-inflammatory and antibacterial properties (7). In addition, several studies have reported that the flavonoid silybin reduced lipid accumulation and oxidative stress in vivo and in vitro (8,9). However, to the best of our knowledge, there are no previous studies that have evaluated the effects of Nob on lipotoxicity.…”

Remedying the Mitochondria to Cure Human Diseases by Natural Products

“…Solanum melongena extract [46] Ganoderma lucidum [47] α-Arbutin [51] Auraptene [54] Oxidative stress Solanum melongena extract [46] Linalool [48] α-Arbutin [51] Naringenin [52] Apigenin [53] Auraptene [54] Apoptosis Ganoderma lucidum [47] Cinnamic acid derivatives [49] Proanthocyanidins [50] Naringenin [52] Apigenin [53] Naringenin [55] Ulmoside A [56] Mitochondrial membrane potential imbalance [59] Polygonatum kingianum [61] Betaine [63] Nicotinamide riboside [64] Puerarin [65] Punica granatum L. [62] Silybin [67] Salvianolic acid B [68] Oxidative stress Cimicifuga racemosa extract [59] Sipjeondaebo-tang [60] Polygonatum kingianum [61] 11 Oxidative Medicine and Cellular Longevity…”

“…Nicotinamide riboside [64] Diosgenin [66] Silybin [67] NecroX-7 [69] Apoptosis Cimicifuga racemosa extract [59] Polygonatum kingianum [61] Betaine [63] Silybin [67] Salvianolic acid B [68] Mitochondrial membrane potential imbalance Cimicifuga racemosa extract [59] Sipjeondaebo-tang [60] Diosgenin [66] Salvianolic acid B [68] NecroX-7 [69] Fatty acid oxidation Silybin [67] NecroX-7 [69] T2DM…”