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1.
PLoS Genet ; 16(8): e1008941, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32760060

RESUMO

Apolipoprotein B-containing lipoproteins (B-lps) are essential for the transport of hydrophobic dietary and endogenous lipids through the circulation in vertebrates. Zebrafish embryos produce large numbers of B-lps in the yolk syncytial layer (YSL) to move lipids from yolk to growing tissues. Disruptions in B-lp production perturb yolk morphology, readily allowing for visual identification of mutants with altered B-lp metabolism. Here we report the discovery of a missense mutation in microsomal triglyceride transfer protein (Mtp), a protein that is essential for B-lp production. This mutation of a conserved glycine residue to valine (zebrafish G863V, human G865V) reduces B-lp production and results in yolk opacity due to aberrant accumulation of cytoplasmic lipid droplets in the YSL. However, this phenotype is milder than that of the previously reported L475P stalactite (stl) mutation. MTP transfers lipids, including triglycerides and phospholipids, to apolipoprotein B in the ER for B-lp assembly. In vitro lipid transfer assays reveal that while both MTP mutations eliminate triglyceride transfer activity, the G863V mutant protein unexpectedly retains ~80% of phospholipid transfer activity. This residual phospholipid transfer activity of the G863V mttp mutant protein is sufficient to support the secretion of small B-lps, which prevents intestinal fat malabsorption and growth defects observed in the mttpstl/stl mutant zebrafish. Modeling based on the recent crystal structure of the heterodimeric human MTP complex suggests the G865V mutation may block triglyceride entry into the lipid-binding cavity. Together, these data argue that selective inhibition of MTP triglyceride transfer activity may be a feasible therapeutic approach to treat dyslipidemia and provide structural insight for drug design. These data also highlight the power of yolk transport studies to identify proteins critical for B-lp biology.


Assuntos
Proteínas de Transporte/genética , Lipídeos/genética , Lipoproteínas/genética , Triglicerídeos/genética , Animais , Fígado Gorduroso/genética , Fígado Gorduroso/patologia , Trato Gastrointestinal/metabolismo , Humanos , Imunoprecipitação , Gotículas Lipídicas/metabolismo , Lipoproteínas/metabolismo , Mutação de Sentido Incorreto/genética , Mutação Puntual/genética , Transporte Proteico/genética , Triglicerídeos/metabolismo , Peixe-Zebra/genética
2.
Transplantation ; 104(8): 1604-1611, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32732837

RESUMO

BACKGROUND: Donor livers with ≥30% macrosteatosis (steatotic livers) represent a possible expansion to the donor pool, but are frequently discarded as they are associated with an increased risk of mortality and graft loss. We hypothesized that there are certain recipient phenotypes that would tolerate donor steatosis well, and are therefore best suited to receive these grafts. METHODS: Using national registry data from the Scientific Registry of Transplant Recipients between 2006 and 2017, we compared 2048 liver transplant recipients of steatotic livers with 69 394 recipients of nonsteatotic (<30%) livers. We identified recipient factors that amplified the impact of donor steatosis on mortality and graft loss using interaction analysis, classifying recipients without these factors as preferred recipients. We compared mortality and graft loss with steatotic versus nonsteatotic livers in preferred and nonpreferred recipients using Cox regression. RESULTS: Preferred recipients of steatotic livers were determined to be first-time recipients with a model for end-stage liver disease 15-34, without primary biliary cirrhosis, and not on life support before transplant. Preferred recipients had no increased mortality risk (hazard ratio [HR]: 0.921.041.16; P = 0.5) or graft loss (HR: 0.931.031.15; P = 0.5) with steatotic versus nonsteatotic livers. Conversely, nonpreferred recipients had a 41% increased mortality risk (HR: 1.171.411.70; P < 0.001) and 39% increased risk of graft loss (HR: 1.161.391.66; P < 0.001) with steatotic versus nonsteatotic livers. CONCLUSIONS: The risks of liver transplantation with steatotic donor livers could be minimized by appropriate recipient matching.


Assuntos
Doença Hepática Terminal/cirurgia , Fígado Gorduroso/diagnóstico , Rejeição de Enxerto/epidemiologia , Transplante de Fígado/efeitos adversos , Seleção de Pacientes , Adulto , Idoso , Aloenxertos/patologia , Aloenxertos/provisão & distribução , Modificador do Efeito Epidemiológico , Doença Hepática Terminal/diagnóstico , Doença Hepática Terminal/mortalidade , Fígado Gorduroso/patologia , Feminino , Rejeição de Enxerto/patologia , Rejeição de Enxerto/prevenção & controle , Rejeição de Enxerto/cirurgia , Sobrevivência de Enxerto , Humanos , Estimativa de Kaplan-Meier , Fígado/patologia , Transplante de Fígado/métodos , Masculino , Pessoa de Meia-Idade , Sistema de Registros/estatística & dados numéricos , Reoperação/estatística & dados numéricos , Medição de Risco , Índice de Gravidade de Doença , Transplantados/estatística & dados numéricos , Resultado do Tratamento , Estados Unidos/epidemiologia
3.
Transplantation ; 104(8): 1612-1618, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32732838

RESUMO

BACKGROUND: Steatotic donor livers (SDLs, ≥30% macrosteatosis on biopsy) are often declined, as they are associated with a higher risk of graft loss, even though candidates may wait an indefinite time for a subsequent organ offer. We sought to quantify outcomes for transplant candidates who declined or accepted an SDL offer. METHODS: We used Scientific Registry of Transplant Recipients offer data from 2009 to 2015 to compare outcomes of 759 candidates who accepted an SDL to 13 362 matched controls who declined and followed candidates from the date of decision (decline or accept) until death or end of study period. We used a competing risk framework to understand the natural history of candidates who declined and Cox regression to compare postdecision survival after declining versus accepting (ie, what could have happened if candidates who declined had instead accepted). RESULTS: Among those who declined an SDL, only 53.1% of candidates were subsequently transplanted, 23.8% died, and 19.4% were removed from the waitlist. Candidates who accepted had a brief perioperative risk period within the first month posttransplant (adjusted hazard ratio [aHR]: 2.493.494.89, P < 0.001), but a 62% lower mortality risk (aHR: 0.310.380.46, P < 0.001) beyond this. Although the long-term survival benefit of acceptance did not vary by candidate model for end-stage liver disease (MELD), the short-term risk period did. MELD 6-21 candidates who accepted an SDL had a 7.88-fold higher mortality risk (aHR: 4.807.8812.93, P < 0.001) in the first month posttransplant, whereas MELD 35-40 candidates had a 68% lower mortality risk (aHR: 0.110.320.90, P = 0.03). CONCLUSIONS: Appropriately selected SDLs can decrease wait time and provide substantial long-term survival benefit for liver transplant candidates.


Assuntos
Seleção do Doador/estatística & dados numéricos , Doença Hepática Terminal/cirurgia , Fígado Gorduroso/patologia , Transplante de Fígado/métodos , Transplantados/estatística & dados numéricos , Idoso , Aloenxertos/patologia , Aloenxertos/provisão & distribução , Biópsia , Tomada de Decisões , Doença Hepática Terminal/mortalidade , Fígado Gorduroso/diagnóstico , Feminino , Seguimentos , Humanos , Fígado/patologia , Transplante de Fígado/estatística & dados numéricos , Masculino , Pessoa de Meia-Idade , Período Perioperatório/mortalidade , Período Perioperatório/estatística & dados numéricos , Sistema de Registros/estatística & dados numéricos , Medição de Risco/estatística & dados numéricos , Fatores de Risco , Índice de Gravidade de Doença , Análise de Sobrevida , Transplantados/psicologia , Resultado do Tratamento , Estados Unidos/epidemiologia , Listas de Espera/mortalidade
4.
Life Sci ; 257: 118118, 2020 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-32702445

RESUMO

AIMS: Recent findings have instituted the role of hyperglycemia-related AGE/RAGE and NF-κB in instigating reactive oxygen species (ROS) mediated mitochondrial dysfunction and apoptosis of hepatocyte, which leads to steatohepatitis. Naringin, a flavanone glycoside found to possess myriads of pharmacological benefits along with its antioxidant and anti-inflammatory properties. Consequently, we aimed to decipher the effect of naringin on RAGE/NF-κB mediated mitochondrial apoptosis in type 2 diabetes mellitus (T2DM)-induced steatohepatitis. MAIN METHODS: Hepatic HepG2 cells were cultured in palmitic acid medium with and without naringin. Lipid content was examined by Oil Red O and Nile Red staining. Cellular apoptosis was determined by Annexin V-FITC/PI staining. An experimental T2DM-induced steatohepatitis was developed in Sprague Dawley rats by high-fat diet (HFD) for 12 weeks. The naringin was administrated orally at a dose of 100 mg/kg, daily for eight weeks. Glucose and insulin tolerance test was performed. Liver sections were stained by hematoxylin-eosin and picrosirius red. The mRNA and protein expression of RAGE and NF-κB were determined by qPCR, Immunofluorescence, and Immunoblotting. Mitochondrial membrane potential (MMP), cellular and mitochondrial ROS were measured by FACS. KEY FINDINGS: Palmitic acid encountered HepG2 cells and HFD fed rats exhibited hyperlipidemia, insulin resistance, abnormal aminotransferases, steatosis, and fibrosis. Besides, the level of AGEs, RAGE, NF-κB, and oxidative stress were exacerbated. Moreover, MMP, cellular and mitochondrial ROS were altered in diabetic rats. Nevertheless, the naringin treatment ameliorated the steatohepatitis by improving the levels of aforementioned parameters. SIGNIFICANCE: Collectively, these findings suggested anti-steatohepatitis potential of naringin in diabetics.


Assuntos
Antioxidantes/uso terapêutico , Apoptose/efeitos dos fármacos , Diabetes Mellitus Tipo 2/complicações , Fígado Gorduroso/tratamento farmacológico , Flavanonas/uso terapêutico , Mitocôndrias/efeitos dos fármacos , NF-kappa B/metabolismo , Receptor para Produtos Finais de Glicação Avançada/metabolismo , Animais , Diabetes Mellitus Experimental/complicações , Fígado Gorduroso/etiologia , Fígado Gorduroso/patologia , Imunofluorescência , Teste de Tolerância a Glucose , Células Hep G2/efeitos dos fármacos , Humanos , Insulina/sangue , Fígado/patologia , Masculino , Ratos , Ratos Sprague-Dawley , Espécies Reativas de Oxigênio/metabolismo , Reação em Cadeia da Polimerase em Tempo Real
5.
PLoS One ; 15(7): e0236506, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32730287

RESUMO

BACKGROUND: Few studies report the effects of tamoxifen intake and the occurrence of de novo fatty liver and the deterioration of existing fatty liver. The aim of this study was to investigate the effects of tamoxifen on fatty change of liver over time and also the impact of fatty liver on the prognosis of patients with breast cancer. METHODS: This was a single-center, retrospective study of patients who were diagnosed with primary breast cancer from January 2007 to July 2017. 911 consecutive patients were classified into three groups according to treatment method: tamoxifen group, aromatase inhibitor (AI) group, and control group. RESULTS: Median treatment duration was 49 months (interquartile range, IQR; 32-58) and median observational period was 85 months (IQR; 50-118). Long-term use of tamoxifen significantly aggravated fatty liver status compared to AI or control groups [hazard ratio (HR): 1.598, 95% confidence interval (CI): 1.173-2.177, P = 0.003] after adjusting other factors. When analyzed separately depending on pre-existing fatty liver at baseline, tamoxifen was involved in the development of de novo fatty liver [HR: 1.519, 95% CI: 1.100-2.098, P = 0.011) and had greater effect on fatty liver worsening (HR: 2.103, 95% CI: 1.156-3.826, P = 0.015). However, the progression of fatty liver did not significantly affect the mortality of breast cancer patients. CONCLUSIONS: Tamoxifen had a significant effect on the fatty liver status compared to other treatment modalities in breast cancer patients. Although fatty liver did not affect the prognosis of breast cancer, meticulous attention to cardiovascular disease or other metabolic disease should be paid when used for a long time.


Assuntos
Antineoplásicos Hormonais/uso terapêutico , Neoplasias da Mama/tratamento farmacológico , Fígado Gorduroso/diagnóstico , Tamoxifeno/efeitos adversos , Adulto , Antineoplásicos Hormonais/efeitos adversos , Inibidores da Aromatase/uso terapêutico , Neoplasias da Mama/mortalidade , Neoplasias da Mama/patologia , Estudos de Casos e Controles , Duração da Terapia , Fígado Gorduroso/etiologia , Fígado Gorduroso/patologia , Feminino , Humanos , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Pontuação de Propensão , Modelos de Riscos Proporcionais , Estudos Retrospectivos , Fatores de Risco , Índice de Gravidade de Doença , Taxa de Sobrevida , Tamoxifeno/uso terapêutico
6.
PLoS One ; 15(7): e0236741, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32730300

RESUMO

Aryl hydrocarbon receptor (AHR) agonists such as dioxin have been associated with obesity and the development of diabetes. Whole-body Ahr knockout mice on high-fat diet (HFD) have been shown to resist obesity and hepatic steatosis. Tissue-specific knockout of Ahr in mature adipocytes via adiponectin-Cre exacerbates obesity while knockout in liver increases steatosis without having significant effects on obesity. Our previous studies demonstrated that treatment of subcutaneous preadipocytes with exogenous or endogenous AHR agonists disrupts maturation into functional adipocytes in vitro. Here, we used platelet-derived growth factor receptor alpha (Pdgfrα)-Cre mice, a Cre model previously established to knock out genes in preadipocyte lineages and other cell types, but not liver cells, to further define AHR's role in obesity. We demonstrate that Pdgfrα-Cre Ahr-floxed (Ahrfl/fl) knockout mice are protected from HFD-induced obesity compared to non-knockout Ahrfl/fl mice (control mice). The Pdgfrα-Cre Ahrfl/fl knockout mice were also protected from increased adiposity, enlargement of adipocyte size, and liver steatosis while on the HFD compared to control mice. On a regular control diet, knockout and non-knockout mice showed no differences in weight gain, indicating the protective phenotype arises only when animals are challenged by a HFD. At the cellular level, cultured cells from brown adipose tissue (BAT) of Pdgfrα-Cre Ahrfl/fl mice were more responsive than cells from controls to transcriptional activation of the thermogenic uncoupling protein 1 (Ucp1) gene by norepinephrine, suggesting an ability to burn more energy under certain conditions. Collectively, our results show that knockout of Ahr mediated by Pdgfrα-Cre is protective against diet-induced obesity and suggest a mechanism by which enhanced UCP1 activity within BAT might confer these effects.


Assuntos
Fatores de Transcrição Hélice-Alça-Hélice Básicos/fisiologia , Dieta Hiperlipídica/efeitos adversos , Fígado Gorduroso/prevenção & controle , Integrases/metabolismo , Obesidade/prevenção & controle , Receptor alfa de Fator de Crescimento Derivado de Plaquetas/fisiologia , Receptores de Hidrocarboneto Arílico/fisiologia , Adiposidade , Animais , Metabolismo Energético , Fígado Gorduroso/etiologia , Fígado Gorduroso/patologia , Feminino , Resistência à Insulina , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Obesidade/etiologia , Obesidade/patologia , Termogênese
7.
Updates Surg ; 72(3): 595-604, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32449031

RESUMO

BACKGROUND: The role of machine perfusion (MP) in the evaluation of liver grafts with macrovesicular steatosis (MaS) remains ill-defined as only a limited number of studies has been reported. The objective of the current study was to provide a systematic review to evaluate the role of MP in the setting of MaS livers. METHODS: A systematic review, according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines was performed. Eligible articles published up to April 2019 were included using the MEDLINE, Scopus, and Google Scholar databases. RESULTS: Among the 422 articles screened, only 16 papers met the inclusion criteria. A total of 54 cases of MP use before liver transplantation were included. Sixteen (29.6%) grafts were from donors after circulatory death. In 22 (40.7%) cases, hypothermic machine perfusion was performed. Normothermic machine perfusion was done in the remaining 32 (59.3%) cases. According to the histological results of the donor core biopsy, a MaS value < 30% was observed in 41 (75.9%) cases, whereas 13 (24.1%) patients had moderate-to-severe (≥ 30%) MaS. Following categorization of the pooled population according to the presence of moderate-to-severe (≥ 30%) MaS in the donor graft, no differences were noted in terms of post-transplant death or severe complications following MP. There was no correlation between the proportion of MaS in the donor graft relative to post-transplant peak ALT among patients treated with MP. Among the entire pooled cohort, there was also no correlation between MaS values and ALT peak (R = 0.13; P = 0.42). CONCLUSIONS: MP appears to be feasible and safe in MaS livers. Experience to date has been very limited, and the benefit of MP remains not determined. Prospective studies will need to define better the potential effect of "defatting" drugs used during the perfusion process on MaS.


Assuntos
Fígado Gorduroso , Transplante de Fígado/métodos , Preservação de Órgãos/instrumentação , Preservação de Órgãos/métodos , Perfusão/métodos , Doadores de Tecidos , Transplantes/patologia , Alanina Transaminase/metabolismo , Biomarcadores/metabolismo , Fígado Gorduroso/diagnóstico , Fígado Gorduroso/patologia , Humanos , Segurança
8.
Mol Cell ; 79(1): 30-42.e4, 2020 07 02.
Artigo em Inglês | MEDLINE | ID: mdl-32473093

RESUMO

Autophagy is activated by prolonged fasting but cannot overcome the ensuing hepatic lipid overload, resulting in fatty liver. Here, we describe a peroxisome-lysosome metabolic link that restricts autophagic degradation of lipids. Acyl-CoA oxidase 1 (Acox1), the enzyme that catalyzes the first step in peroxisomal ß-oxidation, is enriched in liver and further increases with fasting or high-fat diet (HFD). Liver-specific Acox1 knockout (Acox1-LKO) protected mice against hepatic steatosis caused by starvation or HFD due to induction of autophagic degradation of lipid droplets. Hepatic Acox1 deficiency markedly lowered total cytosolic acetyl-CoA levels, which led to decreased Raptor acetylation and reduced lysosomal localization of mTOR, resulting in impaired activation of mTORC1, a central regulator of autophagy. Dichloroacetic acid treatment elevated acetyl-CoA levels, restored mTORC1 activation, inhibited autophagy, and increased hepatic triglycerides in Acox1-LKO mice. These results identify peroxisome-derived acetyl-CoA as a key metabolic regulator of autophagy that controls hepatic lipid homeostasis.


Assuntos
Acetilcoenzima A/metabolismo , Acil-CoA Oxidase/fisiologia , Autofagia , Ácidos Graxos/química , Fígado Gorduroso/patologia , Alvo Mecanístico do Complexo 1 de Rapamicina/metabolismo , Peroxissomos/química , Acetilação , Animais , Proteína 5 Relacionada à Autofagia/fisiologia , Dieta Hiperlipídica/efeitos adversos , Jejum , Fígado Gorduroso/etiologia , Fígado Gorduroso/metabolismo , Feminino , Masculino , Alvo Mecanístico do Complexo 1 de Rapamicina/genética , Camundongos , Camundongos Knockout , Mitocôndrias/metabolismo , Oxirredução , Peroxissomos/metabolismo , Proteína Regulatória Associada a mTOR/genética , Proteína Regulatória Associada a mTOR/metabolismo
9.
Transplant Proc ; 52(5): 1318-1324, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32439332

RESUMO

OBJECTIVES: No study has investigated the short-term effect of acute insulin resistance on liver steatosis in critically ill condition. We analyzed the effects of critically ill conditions of brain-dead donors (BDDs) on the development and progression of liver steatosis to investigate the influencing factors. METHODS: This study was conducted retrospectively between January 2003 and December 2017. BDDs were for organ procurement. BDDs with body mass indexes (BMIs) < 18.5 kg/m2 and ≥ 30 kg/m2 were excluded. Liver steatosis was defined as ≥5% of the fat vacuole. The serum glucose level (SGL) was used to reflect insulin resistance. RESULTS: Of the 179 BDDs, 87 (48.6%) had liver steatosis. BMI (r = 0.176, P = .019) and SGL (r = 0.267, P < .001) were correlated with steatosis. The length of the predonation period (LPDP) was negatively correlated with steatosis (r = -0.379, P < .001). BMI (odds ratio 1.266, P = .002), SGL ≥180 mg/dL (odds ratio 2.825, P = .003), and LPDP (odds ratio 0.885, P = .001) were independent risk factors for liver steatosis. CONCLUSION: Liver steatosis is related to the SGL and BMI. Liver steatosis develops acutely in the early phase of critical illness and patients recover gradually.


Assuntos
Fígado Gorduroso , Transplante de Fígado , Doadores de Tecidos/provisão & distribução , Transplantes/patologia , Adulto , Índice de Massa Corporal , Morte Encefálica , Estado Terminal , Fígado Gorduroso/etiologia , Fígado Gorduroso/patologia , Feminino , Humanos , Resistência à Insulina , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Fatores de Risco
10.
Nat Commun ; 11(1): 1517, 2020 03 23.
Artigo em Inglês | MEDLINE | ID: mdl-32251290

RESUMO

Leptin stimulates the sympathetic nervous system (SNS), energy expenditure, and weight loss; however, the underlying molecular mechanism remains elusive. Here, we uncover Sh2b1 in leptin receptor (LepR) neurons as a critical component of a SNS/brown adipose tissue (BAT)/thermogenesis axis. LepR neuron-specific deletion of Sh2b1 abrogates leptin-stimulated sympathetic nerve activation and impairs BAT thermogenic programs, leading to reduced core body temperature and cold intolerance. The adipose SNS degenerates progressively in mutant mice after 8 weeks of age. Adult-onset ablation of Sh2b1 in the mediobasal hypothalamus also impairs the SNS/BAT/thermogenesis axis; conversely, hypothalamic overexpression of human SH2B1 has the opposite effects. Mice with either LepR neuron-specific or adult-onset, hypothalamus-specific ablation of Sh2b1 develop obesity, insulin resistance, and liver steatosis. In contrast, hypothalamic overexpression of SH2B1 protects against high fat diet-induced obesity and metabolic syndromes. Our results unravel an unrecognized LepR neuron Sh2b1/SNS/BAT/thermogenesis axis that combats obesity and metabolic disease.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Fígado Gorduroso/patologia , Resistência à Insulina , Neurônios/metabolismo , Obesidade/patologia , Proteínas Adaptadoras de Transdução de Sinal/genética , Tecido Adiposo Marrom/inervação , Tecido Adiposo Marrom/metabolismo , Tecido Adiposo Marrom/patologia , Animais , Dieta Hiperlipídica/efeitos adversos , Modelos Animais de Doenças , Fígado Gorduroso/etiologia , Feminino , Técnicas de Introdução de Genes , Técnicas de Inativação de Genes , Humanos , Hipotálamo/patologia , Leptina/metabolismo , Fígado/patologia , Masculino , Camundongos , Camundongos Transgênicos , Obesidade/etiologia , Receptores para Leptina/metabolismo , Sistema Nervoso Simpático/fisiologia , Termogênese/fisiologia
11.
Med Sci Monit ; 26: e921887, 2020 Mar 19.
Artigo em Inglês | MEDLINE | ID: mdl-32191680

RESUMO

BACKGROUND Recent studies have suggested that hepatocyte senescence could contribute to hepatic steatosis and its progression in nonalcoholic fatty liver disease (NAFLD). However, the underlying mechanism causing hepatocyte senescence in this pathological condition is still unclear. A thorough understanding of the mechanism could provide a new target for therapeutic intervention. The purpose of this study was to investigate the role of p66shc in hepatocyte senescence and hepatocyte damage in NAFLD progression. MATERIAL AND METHODS We examined the expression levels of hepatic p66shc and senescence markers in rats and humans with NAFLD, and we assessed the effect of p66shc knockdown or overexpression on senescence and steatosis in human liver cells. RESULTS In this study, we showed that increased hepatic p66shc expression was consistent with upregulated expression of the following senescence markers in NAFLD rats: heterochromatin protein-1-beta (HP1ß), p16, p21, and p53. Furthermore, senescence and steatosis could be induced in hepatoblastoma cell line (HepG2) cells when cells were stimulated with a low concentration of H2O2, and this effect was significantly alleviated by knockdown of p66shc. However, overexpression of p66shc could promote senescence and steatosis in L02 cells. Finally, increased hepatic p66shc protein levels correlated with enhanced expression of the senescence marker p21 and mirrored the degree of disease severity in NAFLD patients. CONCLUSIONS Our findings indicated that the increase in hepatocyte senescence and steatosis in NAFLD may be caused by the upregulation of p66shc expression, implying that strategies for p66shc-mediated regulation of hepatocyte senescence may provide new therapeutic tools for NAFLD.


Assuntos
Senescência Celular , Fígado Gorduroso/patologia , Hepatopatia Gordurosa não Alcoólica/patologia , Animais , Senescência Celular/fisiologia , Progressão da Doença , Fígado Gorduroso/metabolismo , Células Hep G2 , Hepatócitos/metabolismo , Humanos , Hepatopatia Gordurosa não Alcoólica/metabolismo , Ratos , Transdução de Sinais , Proteína 1 de Transformação que Contém Domínio 2 de Homologia de Src
12.
Am J Physiol Gastrointest Liver Physiol ; 318(5): G955-G965, 2020 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-32200644

RESUMO

Functional fermentable fibers are considered essential for a healthy diet. Recently, we demonstrated that gut microbiota dysbiotic mice fed an inulin-containing diet (ICD) developed hepatocellular carcinoma (HCC) within 6 mo. In particular, a subset of Toll-like receptor 5-deficient (T5KO) mice prone to HCC exhibited rapid onset of hyperbilirubinemia (HB) and cholemia; these symptoms provide rationale that ICD induces cholestasis. Our objective in the present study was to determine whether inulin-fed T5KO-HB mice exhibit other known consequences of cholestasis, including essential fatty acid and fat-soluble vitamin deficiencies. Here, we measured hepatic fatty acids and serum vitamin A and D levels from wild-type (WT), T5KO low bilirubin (LB) and T5KO-HB mice fed ICD for 4 wk. Additionally, hepatic RNAseq and proteomics were performed to ascertain other metabolic alterations. Compared with WT and T5KO-LB, T5KO-HB mice exhibited steatorrhea, i.e., ~50% increase in fecal lipids. This could contribute to the significant reduction of linoleate in hepatic neutral lipids in T5KO-HB mice. Additionally, serum vitamins A and D were ~50% reduced in T5KO-HB mice, which was associated with metabolic compromises. Overall, our study highlights that fermentable fiber-induced cholestasis is further characterized by depletion of macro-and micronutrients.NEW & NOTEWORTHY Feeding a dietary, fermentable fiber diet to a subset of Toll-like receptor 5 deficient (T5KO) mice induces early onset hyperbilirubinemia and cholemia that later manifests to hepatocellular carcinoma (HCC). Our study highlights that fermentable fiber-induced cholestasis is characterized with modest macro- and micronutrient deficiencies that may further contribute to hepatic biliary disease. Compared with chemical induction, immunization, surgery, or genetic manipulation, these findings provide a novel approach to study the cholestatic subtype of HCC.


Assuntos
Fibras na Dieta , Fígado Gorduroso/metabolismo , Absorção Intestinal , Inulina , Metabolismo dos Lipídeos , Fígado/metabolismo , Síndromes de Malabsorção/metabolismo , Receptor 5 Toll-Like/deficiência , Deficiência de Vitamina A/metabolismo , Deficiência de Vitamina D/metabolismo , Animais , Ácidos e Sais Biliares/metabolismo , Colestase/genética , Colestase/metabolismo , Colestase/patologia , Modelos Animais de Doenças , Fígado Gorduroso/genética , Fígado Gorduroso/patologia , Fermentação , Fígado/patologia , Síndromes de Malabsorção/genética , Síndromes de Malabsorção/patologia , Masculino , Camundongos Knockout , Receptor 5 Toll-Like/genética , Deficiência de Vitamina A/genética , Deficiência de Vitamina D/genética
13.
Proc Natl Acad Sci U S A ; 117(14): 8166-8176, 2020 04 07.
Artigo em Inglês | MEDLINE | ID: mdl-32188779

RESUMO

Multiple insulin-regulated enzymes participate in hepatic glycogen synthesis, and the rate-controlling step responsible for insulin stimulation of glycogen synthesis is unknown. We demonstrate that glucokinase (GCK)-mediated glucose phosphorylation is the rate-controlling step in insulin-stimulated hepatic glycogen synthesis in vivo, by use of the somatostatin pancreatic clamp technique using [13C6]glucose with metabolic control analysis (MCA) in three rat models: 1) regular chow (RC)-fed male rats (control), 2) high fat diet (HFD)-fed rats, and 3) RC-fed rats with portal vein glucose delivery at a glucose infusion rate matched to the control. During hyperinsulinemia, hyperglycemia dose-dependently increased hepatic glycogen synthesis. At similar levels of hyperinsulinemia and hyperglycemia, HFD-fed rats exhibited a decrease and portal delivery rats exhibited an increase in hepatic glycogen synthesis via the direct pathway compared with controls. However, the strong correlation between liver glucose-6-phosphate concentration and net hepatic glycogen synthetic rate was nearly identical in these three groups, suggesting that the main difference between models is the activation of GCK. MCA yielded a high control coefficient for GCK in all three groups. We confirmed these findings in studies of hepatic GCK knockdown using an antisense oligonucleotide. Reduced liver glycogen synthesis in lipid-induced hepatic insulin resistance and increased glycogen synthesis during portal glucose infusion were explained by concordant changes in translocation of GCK. Taken together, these data indicate that the rate of insulin-stimulated hepatic glycogen synthesis is controlled chiefly through GCK translocation.


Assuntos
Fígado Gorduroso/patologia , Glucoquinase/metabolismo , Glucose/metabolismo , Glicogênio Hepático/biossíntese , Fígado/metabolismo , Animais , Dieta Hiperlipídica/efeitos adversos , Modelos Animais de Doenças , Fígado Gorduroso/etiologia , Técnicas de Silenciamento de Genes , Glucoquinase/genética , Glucose/administração & dosagem , Glucose-6-Fosfato/análise , Glucose-6-Fosfato/metabolismo , Humanos , Hiperglicemia/etiologia , Hiperglicemia/patologia , Hiperinsulinismo/etiologia , Hiperinsulinismo/patologia , Insulina/metabolismo , Resistência à Insulina , Fígado/patologia , Masculino , Metabolômica , Fosforilação , Ratos
14.
Exp Parasitol ; 212: 107889, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32222527

RESUMO

Human and experimental studies have shown that chronic schistosomiasis mansoni protects against metabolic disorders through direct and indirect pathways. This study aims to investigate the co-morbidity between the acute schistosomiasis and nonalcoholic fatty liver. To address this, male C57BL/6 mice fed a high-fat chow (60% fat) or standard chow (10% fat) for 13 weeks and later infected with 80 Schistosoma mansoni cercariae. Mice were assigned into four groups: uninfected fed standard (USC), uninfected fed high-fat chow (UHFC), infected fed standard (ISC), and infected fed high-fat chow (IHFC). Blood sample and tissues were obtained at nine weeks post-infection (acute schistosomiasis) by necropsy. UHFC mice showed higher body mass, visceral adiposity, impaired glucose tolerance, total cholesterol (TC), low-density lipoprotein cholesterol (LDL-c), triglyceride (TG), and liver steatosis compared to USC mice. IHFC mice showed lower blood lipid levels, blood glucose, improved glucose tolerance, body mass, and liver steatosis (macro and microvesicular) compared to UHFC mice. IHFC showed more massive histopathological changes (sinusoidal fibrosis, hepatocellular ballooning, and inflammatory infiltrates) compared to ISC. In conclusion, the co-morbidity results in both beneficial (friend) and detrimental (foe) for the host. While the acute schistosomiasis improves some metabolic features of metabolic syndrome, comorbidity worsens the liver injury.


Assuntos
Síndrome Metabólica/epidemiologia , Esquistossomose mansoni/epidemiologia , Análise de Variância , Animais , Área Sob a Curva , Biomphalaria/parasitologia , Comorbidade , Dieta Hiperlipídica/efeitos adversos , Modelos Animais de Doenças , Fígado Gorduroso/etiologia , Fígado Gorduroso/patologia , Granuloma/etiologia , Granuloma/patologia , Intestinos/parasitologia , Fígado/patologia , Masculino , Síndrome Metabólica/complicações , Síndrome Metabólica/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Esquistossomose mansoni/complicações , Esquistossomose mansoni/metabolismo , Ganho de Peso
15.
Am J Pathol ; 190(6): 1271-1283, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32188584

RESUMO

Snail is a transcription factor that regulates many cellular events involved in development, homeostasis, and disease. In hepatocellular carcinoma (HCC), Snail induces epithelial-to-mesenchymal transition that confers invasive properties on tumor cells during HCC progression and malignancy. Snail activation observed in HCC mouse models suggests its involvement not only in progression, but also onset of HCC. However, it remains unclear whether Snail directly contributes to HCC initiation or whether it supports HCC initiation promoted by other oncogenes. In this study, we generated mouse models for liver-specific and hepatocyte-specific overexpression of Snail to show the independent roles of Snail in liver homeostasis and disease. Enforced Snail expression resulted in liver and hepatocyte enlargement, inflammatory cell infiltration in the liver, lipid accumulation in hepatocytes, substantial increases in serum alanine aminotransferase and bile acids, yellow discoloration of tissues caused by bilirubin accumulation, and liver tumorigenesis. Snail overexpression suppressed mRNA expression of the tight junction components claudins and occludin and that of proteins associated with bile acid metabolism, leading to disruption of the biliary canaliculus formed among hepatocytes and excretion of abnormal amounts of unusual bile acids from hepatocytes. In conclusion, enforced Snail expression in hepatocytes is sufficient for induction of steatohepatitis and liver tumorigenesis through disruption of the biliary canaliculus and bile acid homeostasis in the liver.


Assuntos
Carcinogênese/metabolismo , Fígado Gorduroso/metabolismo , Hepatócitos/metabolismo , Neoplasias Hepáticas/metabolismo , Fatores de Transcrição da Família Snail/metabolismo , Animais , Ácidos e Sais Biliares/metabolismo , Carcinogênese/genética , Carcinogênese/patologia , Modelos Animais de Doenças , Transição Epitelial-Mesenquimal/fisiologia , Fígado Gorduroso/genética , Fígado Gorduroso/patologia , Regulação Neoplásica da Expressão Gênica , Hepatócitos/patologia , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/patologia , Camundongos , Camundongos Transgênicos , Fatores de Transcrição da Família Snail/genética
16.
PLoS One ; 15(2): e0228889, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32045450

RESUMO

Mesenchymal stem cells (MSCs) are a population of pluripotent cells that have been tested for the treatment of many inflammatory diseases. It remains unclear whether MSCs were effective in treating mice with alcoholic hepatitis (AH) and its underlying mechanism. In the present study, MSCs were isolated from bone marrow of 4-6 week-old C57BL/6N male mice. AH was induced in female mice by chronic-binge ethanol feeding for 10 days. Intraperitoneal (i.p.) transplantation of MSCs or saline were performed in mice on day 10. Blood samples and hepatic tissues were harvested on day 11. Biochemical, liver histological and flow cytometric analyses were performed. Compared to the control mice, the AH mice had significantly increased liver/body weight ratio, serum alanine aminotransferase (ALT) and aspartate aminotransferases (AST), hepatic total cholesterol (TC), triglyceride (TG), malondialdehyde (MDA), hepatic neutrophil and macrophage infiltration (P<0.001), which were markedly reduced by i.p. transplantation of MSCs (P<0.01). Compared to the control mice, the hepatic glutathione (GSH) was prominently lower in the AH mice (P<0.001), which was markedly enhanced after i.p. injection of MSCs (P<0.001). MSCs were effective for the treatment of AH mice, which might be associated with their ability in inhibiting hepatic neutrophil and macrophage infiltration, and alleviating oxidative stress.


Assuntos
Hepatite Alcoólica/terapia , Transplante de Células-Tronco Mesenquimais , Animais , Diferenciação Celular , Modelos Animais de Doenças , Fígado Gorduroso/metabolismo , Fígado Gorduroso/patologia , Fígado Gorduroso/terapia , Feminino , Hepatite Alcoólica/metabolismo , Hepatite Alcoólica/patologia , Metabolismo dos Lipídeos , Fígado/metabolismo , Fígado/patologia , Macrófagos/patologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Infiltração de Neutrófilos , Estresse Oxidativo
17.
Mol Pharmacol ; 97(5): 314-323, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32098797

RESUMO

Farnesoid X receptor (FXR), or NR1H4, protects the liver from insults of various etiologies. A role of FXR in drug-induced liver injury has also been hypothesized yet only marginally investigated. The aim of this study was to assess the effect of FXR activation on gene expression and phenotype of the liver of mice treated with valproic acid (VPA), or 2-propylpentanoic acid, a prototypical hepatotoxic drug. Obeticholic acid (OCA) was used to activate FXR both in mice and in human hepatocellular carcinoma (Huh-7) cells. Next-generation sequencing of mouse liver tissues was performed from control, VPA, and VPA + OCA-treated mice. Pathway analysis validation was performed using real-time reverse-transcription polymerase chain reaction, Western blotting, immunohistochemistry, and fluorometric assays. FXR activation induced antioxidative pathways, which was confirmed by a marked reduction in VPA-induced lipid peroxidation and endoplasmic reticulum stress. In vitro, VPA-induced oxidative stress was independent of lipid accumulation, stemmed from the cytoplasm, and was mitigated by OCA. In the liver of the mice treated with OCA, the levels of cytochrome P450 potentially involved in VPA metabolism were increased. The hepatic lipid-lowering effect observed in animals cotreated with VPA and OCA in comparison with that of animals treated with VPA was associated with regulation of the genes involved in the steatogenic nuclear receptor peroxisome proliferator-activated γ (PPARγ) pathway. In conclusion, pronounced antioxidant activity, repression of the PPARγ pathway, and higher expression of P450 enzymes involved in VPA metabolism may underlie the hepatoprotective of FXR activation during VPA treatment. SIGNIFICANCE STATEMENT: Valproic acid-induced oxidative stress occurs in absence of lipid accumulation and is not of mitochondrial origin. Valproic acid exposure induces the expression of the steatogenic nuclear receptor peroxisome proliferator-activated γ (PPARγ) and its downstream target genes. Constitutive activation of the farnesoid X receptor (FXR) reduces PPARγ hepatic expression and induces hepatic antioxidant activity. The variability in FXR expression level/activity, for instance in individuals carrying loss-of-function genetic variants of the FXR gene, could contribute to valproic acid pharmacokinetic and toxicokinetic profile.


Assuntos
Ácido Quenodesoxicólico/análogos & derivados , Fígado Gorduroso/tratamento farmacológico , Fígado Gorduroso/patologia , Estresse Oxidativo , Ácido Valproico/efeitos adversos , Animais , Antioxidantes/farmacologia , Peso Corporal/efeitos dos fármacos , Linhagem Celular Tumoral , Ácido Quenodesoxicólico/farmacologia , Ácido Quenodesoxicólico/uso terapêutico , Sistema Enzimático do Citocromo P-450/metabolismo , Fígado Gorduroso/induzido quimicamente , Fígado Gorduroso/fisiopatologia , Feminino , Metabolismo dos Lipídeos/efeitos dos fármacos , Fígado/efeitos dos fármacos , Fígado/metabolismo , Fígado/patologia , Fígado/fisiopatologia , Testes de Função Hepática , Camundongos Endogâmicos C57BL , Estresse Oxidativo/efeitos dos fármacos , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Receptores Citoplasmáticos e Nucleares/metabolismo , Transcriptoma/genética
18.
Artigo em Inglês | MEDLINE | ID: mdl-31953228

RESUMO

Elevating evidences suggested roles of peptidoglycan (PGN) for the insulin resistance, metabolic inflammation and liver disorders. But, whether PGN affects the occurrence of steatohepatitis remains unclear. Here, we reported that subcutaneous infusion of purified PGN for 4 weeks significantly increased hepatic levels of triglyceride, inflammation and fibrosis in mice fed normal chow. These alterations were associated with raise in circulating triglyceride, cholesterol, insulin content and inflammatory cytokines. PGN significantly increased triglyceride contents as well as lipogenesis related genes in primary hepatocytes or LO2 cells, either in basal or oleic acid treated conditions. Administration of PGN stimulated the expression of NOD2, as well as phosphorylation of p65 and IκBα, leading to subsequent nuclear translocation of p65. Over-expression of NOD2 significantly enhanced the phosphorylation of p65, levels of nuclear PPARγ and SREBP1, followed by increase in triglyceride contents in LO2 cells treated with or without oleic acid. Further, over-expression of NOD2 significantly augmented the up-regulation of PPARγ induced by rosiglitazone. Inhibition of NFκB blocked the effect of NOD2 on the upregulation of PPARγ. Our study demonstrates that PGN stimulates hepatic lipogenesis by NOD2-NFκB-PPARγ signaling. PGN from intestinal microbiota is thus sufficient to induce the progression of steatohepatitis.


Assuntos
Fígado Gorduroso/metabolismo , Lipogênese , Peptidoglicano/metabolismo , Animais , Fígado Gorduroso/microbiologia , Fígado Gorduroso/patologia , Microbioma Gastrointestinal , Inflamação/metabolismo , Inflamação/microbiologia , Inflamação/patologia , Fígado/metabolismo , Fígado/microbiologia , Fígado/patologia , Masculino , Camundongos Endogâmicos C57BL , Transdução de Sinais
19.
Artigo em Inglês | MEDLINE | ID: mdl-31913683

RESUMO

Induced by overfeeding, hepatic steatosis is a process exploited for the "foie gras" production in mule ducks. To better understand the mechanisms underlying its development, the physiological responses of mule ducks overfed with corn for a duration of 11 days were analyzed. A kinetic analysis of glucose and lipid metabolism and cell protection mechanisms was performed on 96 male mule ducks during overfeeding with three sampling times (after the 4th, the 12th, and the 22nd meal). Gene expression and protein analysis realized on the liver, muscle, and abdominal fat showed an activation of a cholesterol biosynthetic pathway during the complete overfeeding period mainly in livers with significant correlations between its weight and its cholesterolemia (r = 0.88; P < 0.0001) and between the liver weight and the hmgcr and soat1 expression (r = 0.4, P < 0.0001 and r = 0.67; P < 0.0001, respectively). Results also revealed an activation of insulin and amino acid cells signaling a pathway suggesting that ducks boost insulin sensitivity to raise glucose uptake and use via glycolysis and lipogenesis. Cellular stress analysis revealed an upregulation of key autophagy-related gene expression atg8 and sqstm1(P < 0.0001) during the complete overfeeding period, mainly in the liver, in contrast to an induction of cyp2e1(P < 0.0001), suggesting that autophagy could be suppressed during steatosis development. This study has highlighted different mechanisms enabling mule ducks to efficiently handle the starch overload by keeping its liver in a nonpathological state. Moreover, it has revealed potential biomarker candidates of hepatic steatosis as plasma cholesterol for the liver weight.


Assuntos
Glicemia/metabolismo , Patos/metabolismo , Ingestão de Energia , Metabolismo Energético , Fígado Gorduroso/metabolismo , Lipogênese , Fígado/metabolismo , Estresse Fisiológico , Ração Animal , Fenômenos Fisiológicos da Nutrição Animal , Animais , Glicemia/genética , Metabolismo Energético/genética , Fígado Gorduroso/etiologia , Fígado Gorduroso/genética , Fígado Gorduroso/patologia , Regulação Enzimológica da Expressão Gênica , Cinética , Lipogênese/genética , Fígado/patologia , Masculino , Estado Nutricional , Tamanho do Órgão
20.
PLoS One ; 15(1): e0228011, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31978172

RESUMO

There continues to be a significant shortage of donor livers for transplantation. One impediment is the discard rate of fatty, or steatotic, livers because of their poor post-transplant function. Steatotic livers are prone to significant ischemia-reperfusion injury (IRI) and data regarding how best to improve the quality of steatotic livers is lacking. Herein, we use normothermic (37°C) machine perfusion in combination with metabolic and lipidomic profiling to elucidate deficiencies in metabolic pathways in steatotic livers, and to inform strategies for improving their function. During perfusion, energy cofactors increased in steatotic livers to a similar extent as non-steatotic livers, but there were significant deficits in anti-oxidant capacity, efficient energy utilization, and lipid metabolism. Steatotic livers appeared to oxidize fatty acids at a higher rate but favored ketone body production rather than energy regeneration via the tricyclic acid cycle. As a result, lactate clearance was slower and transaminase levels were higher in steatotic livers. Lipidomic profiling revealed ω-3 polyunsaturated fatty acids increased in non-steatotic livers to a greater extent than in steatotic livers. The novel use of metabolic and lipidomic profiling during ex situ normothermic machine perfusion has the potential to guide the resuscitation and rehabilitation of steatotic livers for transplantation.


Assuntos
Fígado Gorduroso/metabolismo , Lipidômica , Metabolômica , Perfusão , Ressuscitação , Temperatura , Trifosfato de Adenosina/biossíntese , Ácidos e Sais Biliares/metabolismo , Ácidos Graxos/metabolismo , Fígado Gorduroso/patologia , Fígado Gorduroso/fisiopatologia , Glucose/metabolismo , Hemodinâmica , Humanos , Fígado/patologia , Fígado/fisiopatologia , Testes de Função Hepática , Oxirredução , Estresse Oxidativo , Resistência Vascular
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