NAFLD e ingesta de fructosa en altas concentraciones: una revisión de la literatura / NAFLD and high fructose intake: a review of literature

Uno de los endulzantes más comúnmente utilizado es la fructosa. La fructosa es directamente metabolizada en el hígado y se puede transformar en glucosa, posteriormente es almacenada como glicógeno constituyéndose en una fuente de energía para los hepatocitos. Todo el exceso de fructosa se convierte en lípidos ejerciendo un efecto tóxico sobre el hígado, similar al producido por el exceso de alcohol, pudiendo provocar hígado graso no alcohólico (NAFLD). El objetivo de esta revisión es reunir hallazgos recientes en relación al efecto de la ingesta de fructosa en altas concentraciones y su relación con el NAFLD.

One of the most commonly used sweeteners is fructose. Fructose is directly metabolized in the liver and can be converted into glucose, later stored as glycogen constituting a source of energy for the hepatocytes. All excess fructose is converted into lipids by exerting a toxic effect on the liver, similar to that produced by excess of alcohol, and can cause nonalcoholic fatty liver (NAFLD). The aim of this review is to gather recent findings regarding the effect of fructose intake at high concentrations and its relationship with NAFLD.

Management Strategies for Liver Fibrosis

Abstract: Liver fibrosis resulting from chronic liver injury are major causes of morbidity and mortality worldwide. Among causes of hepatic fibrosis, viral infection is most common (hepatitis B and C). In addition, obesity rates worldwide have accelerated the risk of liver injury due to nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH). Also liver fibrosis is associated with the consumption of alcohol, or autoimmune hepatitis and chronic cholangiophaties. The response of hepatocytes to inflammation plays a decisive role in the physiopathology of hepatic fibrosis, which involves the recruitment of both pro- and anti-inflammatory cells such as monocytes and macrophages. As well as the production of other cytokines and chemokines, which increase the stimulus of hepatic stellate cells by activating proinflammatory cells. The aim of this review is to identify the therapeutic options available for the treatment of the liver fibrosis, enabling the prevention of progression when is detected in time.

Inhibitory effect of liposomal quercetin on acute hepatitis and hepatic fibrosis induced by concanavalin A

Immune response plays an important role in the development of hepatic fibrosis. In the present study, we investigated the effects of quercetin on hepatitis and hepatic fibrosis induced by immunological mechanism. In the acute hepatitis model, quercetin (2.5 mg/kg) was injected iv into mice 30 min after concanavalin A (Con A) challenge. Mice were sacrificed 4 or 24 h after Con A injection, and aminotransferase tests and histopathological sections were performed. Treatment with quercetin significantly decreased the levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST). Consistent with this observation, treatment with quercetin markedly attenuated the pathologic changes in the liver. A hepatic fibrosis model was also generated in mice by Con A challenge once a week for 6 consecutive weeks. Mice in the experimental group were treated with daily iv injections of quercetin (0.5 mg/kg). Histopathological analyses revealed that treatment with quercetin markedly decreased collagen deposition, pseudolobuli development, and hepatic stellate cells activation. We also examined the effects of quercetin on the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) and transforming growth factor beta (TGF-β) pathways by immunohistochemistry and real-time reverse transcriptase-polymerase chain reaction (RT-PCR). NF-κB and TGF-β production was decreased after treatment with quercetin, indicating that the antifibrotic effect of quercetin is associated with its ability to modulate NF-κB and TGF-β production. These results suggest that quercetin may be an effective therapeutic strategy in the treatment of patients with liver damage and fibrosis.

Parthenolide-induced apoptosis of hepatic stellate cells and anti-fibrotic effects in an in vivo rat model

Parthenolide (PT), a sesquiterpene lactone derived from the plant feverfew, has pro-apoptotic activity in a number of cancer cell types. We assessed whether PT induces the apoptosis of hepatic stellate cells (HCSs) and examined its effects on hepatic fibrosis in an in vivo model. The effects of PT on rat HSCs were investigated in relation to cell growth inhibition, apoptosis, NF-kappaB binding activity, intracellular reactive oxygen species (ROS) generation, and glutathione (GSH) levels. In addition, the anti-fibrotic effects of PT were investigated in a thioacetamide-treated rat model. PT induced growth inhibition and apoptosis in HSCs, as evidenced by cell growth inhibition and apoptosis assays. PT increased the expression of Bax proteins during apoptosis, but decreased the expression of Bcl-2 and Bcl-XL proteins. PT also induced a reduction in mitochondrial membrane potential, poly(ADP-ribose) polymerase cleavage, and caspase-3 activation. PT inhibited TNF-alpha-stimulated NF-kappaB binding activity in HSCs. The pro-apoptotic activity of PT in HSCs was associated with increased intracellular oxidative stress as evidenced by increased intracellular ROS levels and depleted intracellular GSH levels. Furthermore, PT ameliorated hepatic fibrosis significantly in a thioacetamide-treated rat model. In conclusion, PT exhibited pro-apoptotic effects in rat HSCs and ameliorated hepatic fibrosis in a thioacetamide-induced rat model.

Antifibrotic effects of magnesium lithospermate B on hepatic stellate cells and thioacetamide-induced cirrhotic rats

Magnesium lithospermate B (MLB) is one of the major active components of Salvia miltiorrhizae. The anti-oxidative effects of Salvia miltiorrhizae have been previously reported. The aim of this study was to investigate the effect of purified MLB on hepatic fibrosis in rats and on the fibrogenic responses in hepatic stellate cells (HSCs). Hepatic fibrosis was induced in rats by intraperitoneal thioacetamide (TAA) injections over a period of 8 or 12 weeks. MLB was orally administered daily by gavage tube. Serum AST and ALT levels in TAA + MLB group were significantly lower than those in TAA only group at week 8. Hepatic fibrosis was significantly attenuated in TAA + MLB group than in TAA only group at week 8 or 12. Activation of HSCs was also decreased in TAA + MLB group as compared to TAA only group. Hepatic mRNA expression of alpha-smooth muscle actin (alpha-SMA), TGF-beta1, and collagen alpha1(I) was significantly decreased in TAA + MLB group as compared to TAA only group. Incubation with HSCs and MLB (> or =100 microM) for up to 48 h showed no cytotoxicity. MLB suppressed PDGF-induced HSC proliferation. MLB inhibited NF-kappaB transcriptional activation and monocyte chemotactic protein 1 (MCP-1) production in HSCs. MLB strongly suppressed H2O2-induced reactive oxygen species (ROS) generation in HSCs, and MLB inhibited type I collagen secretion in HSCs. We concluded that MLB has potent antifibrotic effect in TAA-treated cirrhotic rats, and inhibits fibrogenic responses in HSCs. These data suggest that MLB has potential as a novel therapy for hepatic fibrosis.

Effect of curcumin on the proliferation and apoptosis of hepatic stellate cells

This study was designed to investigate the effect of curcumin (diferuloylmethane) on the proliferation and apoptosis of hepatic stellate cells (HSC). The cell line HSC-T6 (1.25 x 10(5) cells/mL) was incubated with curcumin and HSC proliferation was detected by a methyl thiazolyl tetrazolium colorimetric assay. HSC apoptosis was detected by flow cytometry, transmission electron microscope and agarose gel electrophoresis. HSC proliferation was significantly inhibited in a concentration-dependent manner (10.6 to 63.5 percent) after incubation with 20-100 ìM curcumin, compared with a control group. At 20, 40, and 60 ìM, after 24 h of incubation, curcumin was associated with a significant increase in the number of HSC in the G2/M phase, and a significant decrease in cell numbers in the S phase (P < 0.05). At these concentrations, curcumin was also associated with an increase in the apoptosis index of 15.3 ± 1.9, 26.7 ± 2.8, and 37.6 ± 4.4 percent, respectively, compared to control (1.9 ± 0.6 percent, P < 0.01). At 40 ìM, the curcumin-induced apoptosis index at 12, 24, 36, and 48 h of incubation was 12.0 ± 2.4, 26.7 ± 3.5, 33.8 ± 1.8, and 49.3 ± 1.6 percent, respectively (P < 0.01). In conclusion, curcumin inhibits the in vitro proliferation of HSCs in the G2/M phase of the cell cycle and also induces apoptosis in a concentration- and time-dependent manner. The in vivo effect of curcumin on HSCs requires further investigation.