Simvastatin Improves Microcirculatory Function in Nonalcoholic Fatty Liver Disease and Downregulates Oxidative and ALE-RAGE Stress

Increased reactive oxidative stress, lipid peroxidation, inflammation, and fibrosis, which contribute to tissue damage and development and progression of nonalcoholic liver disease (NAFLD), play important roles in microcirculatory disorders. We investigated the effect of the modulatory properties of simvastatin (SV) on the liver and adipose tissue microcirculation as well as metabolic and oxidative stress parameters, including the advanced lipoxidation end product–receptors of advanced glycation end products (ALE-RAGE) pathway. SV was administered to an NAFLD model constructed using a high-fat–high-carbohydrate diet (HFHC). HFHC caused metabolic changes indicative of nonalcoholic steatohepatitis; treatment with SV protected the mice from developing NAFLD. SV prevented microcirculatory dysfunction in HFHC-fed mice, as evidenced by decreased leukocyte recruitment to hepatic and fat microcirculation, decreased hepatic stellate cell activation, and improved hepatic capillary network architecture and density. SV restored basal microvascular blood flow in the liver and adipose tissue and restored the endothelium-dependent vasodilatory response of adipose tissue to acetylcholine. SV treatment restored antioxidant enzyme activity and decreased lipid peroxidation, ALE-RAGE pathway activation, steatosis, fibrosis, and inflammatory parameters. Thus, SV may improve microcirculatory function in NAFLD by downregulating oxidative and ALE-RAGE stress and improving steatosis, fibrosis, and inflammatory parameters

Hepatic microvascular dysfunction and increased advanced glycation end products are components of non-alcoholic fatty liver disease

Submitted by Sandra Infurna ([email protected]) on 2017-11-16T13:43:19Z No. of bitstreams: 1 evelyn_pereira_etal_IOC_2017.pdf: 16299047 bytes, checksum: 784f4efe183b1d6189c0f5a1b9e9a610 (MD5)Approved for entry into archive by Sandra Infurna ([email protected]) on 2017-11-16T13:53:46Z (GMT) No. of bitstreams: 1 evelyn_pereira_etal_IOC_2017.pdf: 16299047 bytes, checksum: 784f4efe183b1d6189c0f5a1b9e9a610 (MD5)Made available in DSpace on 2017-11-16T13:53:46Z (GMT). No. of bitstreams: 1 evelyn_pereira_etal_IOC_2017.pdf: 16299047 bytes, checksum: 784f4efe183b1d6189c0f5a1b9e9a610 (MD5) Previous issue date: 2017Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Investigação Cardiovascular. Rio de Janeiro, RJ. Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Investigação Cardiovascular. Rio de Janeiro, RJ. Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Investigação Cardiovascular. Rio de Janeiro, RJ. Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Investigação Cardiovascular. Rio de Janeiro, RJ. Brasil.Universidade Federal do Rio de Janeiro. Laboratório de Cardiologia Celular e Molecular. Rio de Janeiro, RJ, Brasil / Universidade Federal do Rio de Janeiro. Centro Nacional de Biologia Estrutura. e Bioimagem. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Patologia. Rio de Janeiro, RJ. Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Patologia. Rio de Janeiro, RJ. Brasil.Universidade Federal do Rio de Janeiro. Laboratório de Endocrinologia Molecular. Rio de Janeiro, RJ, Brasil.Universidade Federal do Rio de Janeiro. Laboratório de Endocrinologia Molecular. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Imunofarmacologia. Rio de Janeiro, RJ. Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Imunofarmacologia. Rio de Janeiro, RJ. Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Investigação Cardiovascular. Rio de Janeiro, RJ. Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Investigação Cardiovascular. Rio de Janeiro, RJ. Brasil.This study aimed to investigate the pathophysiology of hepatic microcirculatory dysfunction in non-alcoholic fatty liver disease (NAFLD)

Ultrasonographic analyses of steatotic livers.

<p>Liver area (A), liver horizontal (B) and vertical diameter (C), portal vein diameter (D), liver ultrasonographic representative images of control (CTL)(E) and high-fed diet (HFD)-fed rats (F). *<i>P</i> < .05 versus control; **<i>P</i> < .01 versus control.</p

Participation of advanced glycation end product (AGE) and the receptor for advanced glycation end products (RAGE) in NAFLD.

<p>AGE deposition in the liver (A) and serum of control and HFD-fed rats (HFD)(B). RAGE protein (C) and mRNA (D) levels where compared between the groups. Liver AGE content <i>versus</i> severity of steatosis is shown in E. *<i>P</i> < .05 versus control; **<i>P</i> < .01 versus control.</p

Hepatic microcirculation alterations in NAFLD.

<p>Representative image of the liver microcirculation of CTL (A and B) and HFD-fed rats (C and D) assessed by intravital microscopy; off-line quantification of rolling (E) and adhesion (F) of leukocytes in the sinusoids and post-sinusoids venules. Liver microvascular blood flow evaluated by laser speckle contras imaging (LSCI) is represented in G. Values are presented as the mean (± SEM). ***<i>P</i> < .001 versus control. Arrows indicate rolling/adherent leukocytes on sinusoids and asterisks rolling/adherent leukocytes on post-sinusoids venules.</p

Oxidative stress and inflammatory parameters in the liver of control (CTL) and HFD-fed rats (HFD).

<p>Levels of malondialdehyde (MDA) indicating lipid peroxidation assessed by thiobarbituric acid reactive species (TBARs)(A); Real-time PCR analyses of mRNA transcript levels of genes coding for pro-oxidant gene NADPH oxidase (B) and anti-oxidant enzymes catalase (C). Catalase enzyme activity in the liver of control (CTL) and HFD-fed rats for 20 weeks (D). Serum and hepatic levels of TNF-α (E and G, respectively) and IL-1β (F and H, respectively) in control (CTL) and HFD-fed rats for 20 weeks assessed by ELISA quantification. *<i>P</i> < .05 versus control. **<i>P</i> < .01 versus control, ***<i>P</i> < .001 versus control. For this analysis at least six animals of each group were analysed and three independent experiments performed.</p

Insulin signalling components in the liver of NAFLD rat model.

<p>Expression of insulin signalling components in the liver of Wistar rats fed a standard chow (CTL) or high-fat diet (HFD) for 20 weeks was assessed by Western blot (A). The histogram represents means ± SEM of the densitometric scans for the protein bands of insulin pathway components, normalised by cyclophilin (B) and the ratio IRβ/p-IRβ (C) and p-AMPK/AMPK (D). *P < .05 versus control; **P < .01 versus control.</p

Evaluation of steatosis, inflammation and lipid deposition in the liver of HFD-fed rats.

<p>Representative images of livers from the control (A) and high fat diet (B, C, D) groups stained with Hematoxilin and Eosin or Oil-Red O staining. A. Control showing no histopathologic alterations. B. Macrovesicles in individual cells, suggesting macroesteatosis, surrounded by some microsteatotic cells. C. Moderate level of steatosis with several microsteatotic cells. D. Severe hepatic steatosis: almost all cells contain microvesicles and some contain macrovesicles. No fibrotic or inflammatory alterations were observed. Arrows indicate macroesteatotic cells and arrowheads microesteatotic cells. Neutral lipid accumulation in liver from control (E) and high fat diet (G) groups. Quantification of oil-red stained sections (G). Magnification is ×20. Insets from the images are magnified five times in order to highlight the steatosis and lipid-staining morphology. a.u., arbitrary units. **<i>P</i> < .01, compared with control rats.</p