Functional gastrointestinal disorders(FGID)are heterogeneous disorders with a variety of clinical manifestations,primarily defined by signs and symptoms rather than a definite underlying cause.Their pathophysiology re...Functional gastrointestinal disorders(FGID)are heterogeneous disorders with a variety of clinical manifestations,primarily defined by signs and symptoms rather than a definite underlying cause.Their pathophysiology remains obscure and,although it is expected to differ according to the specific FGID,disruptions in the brain-gut axis are now thought to be a common denominator in their pathogenesis.The hormone ghrelin is an important component of this axis,exerting a wide repertoire of physiological actions,including regulation of gastrointestinal motility and protection of mucosal tissue.Ghrelin's gene shows genetic polymorphism,while its protein product undergoes complex regulation and metabolism in the human body.Numerous studies have studied ghrelin's relation to the emergence of FGIDs,its potential value as an index of disease severity and as a predictive marker for symptom relief during attempted treatment.Despite the mixed results currently available in scientific literature,the plethora of statistically significant findings shows that disruptions in ghrelin genetics and expression are plausibly related to FGID pathogenesis.The aim of this paper is to review current literature studying these associations,in an effort to uncover certain patterns of alterations in both genetics and expression,which could delineate its true contribution to FGID emergence,either as a causative agent or as a pathogenetic intermediate.展开更多
This article reviews the evidence that ties the development of hepatocellular carcinoma (HCC) to the natural immune pro-inflammatory response to chronic liver disease, with a focus on the role of Toll-like receptor (T...This article reviews the evidence that ties the development of hepatocellular carcinoma (HCC) to the natural immune pro-inflammatory response to chronic liver disease, with a focus on the role of Toll-like receptor (TLR) signaling as the mechanism of liver stem cell/progenitor transformation to HCC. Two exemplary models of this phenomenon are reviewed in detail. One model applies chronic ethanol/lipopolysaccharide feeding to the activated TLR4 signaling pathway. The other applies chronic feeding of a carcinogenic drug, in which TLR2 and 4 signaling pathways are activated. In the drug-induced model, two major methyl donors, S-adenosylmethionine and betaine, prevent the upregulation of the TLR signaling pathways and abrogate the stem cell/progenitor proliferation response when fed with the carcinogenic drug. This observation supports a nutritional approach to liver cancer prevention and treatment. The observation that upregulation of the TLR signaling pathways leads to liver tumor formation gives evidence to the popular concept that the chronic pro-inflammatory response is an important mechanism of liver oncogenesis. It provides a nutritional approach, which could prevent HCC from developing in many chronic liver diseases.展开更多
Hepatitis D virus(HDV) is a defective circular shape single stranded HDV RNA virus with two types of viral proteins,small and large hepatitis D antigens,surrounded by hepatitis B surface antigen.Superinfection with HD...Hepatitis D virus(HDV) is a defective circular shape single stranded HDV RNA virus with two types of viral proteins,small and large hepatitis D antigens,surrounded by hepatitis B surface antigen.Superinfection with HDV in chronic hepatitis B is associated with a more threatening form of liver disease leading to rapid progression to cirrhosis.In spite of some controversy in the epidemiological studies,HDV infection does increase the risk of hepatocellular carcinoma(HCC) compared to hepatitis B virus(HBV) monoinfection.Hepatic decompensation,rather than development of HCC,is the first usual clinical endpoint during the course of HDV infection.Oxidative stress as a result of severe necroinflammation may progress to HCC.The large hepatitis D antigen is a regulator of various cellular functions and an activator of signal transducer and activator of transcription(STAT)3 and the nuclear factor kappa B pathway.Another proposed epigenetic mechanism by which HCC may form is the aberrant silencing of tumor suppressor genes by DNA Methyltransferases.HDV antigens have also been associated with increased histone H3 acetylation of the clusterin promoter.This enhances the expression of clusterin in infected cells,increasing cell survival potential.Any contribution of HBV DNA integration with chromosomes of infected hepatocytes is not clear at this stage.The targeted inhibition of STAT3 and cyclophilin,and augmentation of peroxisome proliferatoractivated receptor γ have a potential therapeutic role in HCC.展开更多
文摘Functional gastrointestinal disorders(FGID)are heterogeneous disorders with a variety of clinical manifestations,primarily defined by signs and symptoms rather than a definite underlying cause.Their pathophysiology remains obscure and,although it is expected to differ according to the specific FGID,disruptions in the brain-gut axis are now thought to be a common denominator in their pathogenesis.The hormone ghrelin is an important component of this axis,exerting a wide repertoire of physiological actions,including regulation of gastrointestinal motility and protection of mucosal tissue.Ghrelin's gene shows genetic polymorphism,while its protein product undergoes complex regulation and metabolism in the human body.Numerous studies have studied ghrelin's relation to the emergence of FGIDs,its potential value as an index of disease severity and as a predictive marker for symptom relief during attempted treatment.Despite the mixed results currently available in scientific literature,the plethora of statistically significant findings shows that disruptions in ghrelin genetics and expression are plausibly related to FGID pathogenesis.The aim of this paper is to review current literature studying these associations,in an effort to uncover certain patterns of alterations in both genetics and expression,which could delineate its true contribution to FGID emergence,either as a causative agent or as a pathogenetic intermediate.
基金Supported by NIH/NIAAA 8116Alcohol Center Grant on Liver and Pancreas P50-011999, Morphology Core
文摘This article reviews the evidence that ties the development of hepatocellular carcinoma (HCC) to the natural immune pro-inflammatory response to chronic liver disease, with a focus on the role of Toll-like receptor (TLR) signaling as the mechanism of liver stem cell/progenitor transformation to HCC. Two exemplary models of this phenomenon are reviewed in detail. One model applies chronic ethanol/lipopolysaccharide feeding to the activated TLR4 signaling pathway. The other applies chronic feeding of a carcinogenic drug, in which TLR2 and 4 signaling pathways are activated. In the drug-induced model, two major methyl donors, S-adenosylmethionine and betaine, prevent the upregulation of the TLR signaling pathways and abrogate the stem cell/progenitor proliferation response when fed with the carcinogenic drug. This observation supports a nutritional approach to liver cancer prevention and treatment. The observation that upregulation of the TLR signaling pathways leads to liver tumor formation gives evidence to the popular concept that the chronic pro-inflammatory response is an important mechanism of liver oncogenesis. It provides a nutritional approach, which could prevent HCC from developing in many chronic liver diseases.
文摘Hepatitis D virus(HDV) is a defective circular shape single stranded HDV RNA virus with two types of viral proteins,small and large hepatitis D antigens,surrounded by hepatitis B surface antigen.Superinfection with HDV in chronic hepatitis B is associated with a more threatening form of liver disease leading to rapid progression to cirrhosis.In spite of some controversy in the epidemiological studies,HDV infection does increase the risk of hepatocellular carcinoma(HCC) compared to hepatitis B virus(HBV) monoinfection.Hepatic decompensation,rather than development of HCC,is the first usual clinical endpoint during the course of HDV infection.Oxidative stress as a result of severe necroinflammation may progress to HCC.The large hepatitis D antigen is a regulator of various cellular functions and an activator of signal transducer and activator of transcription(STAT)3 and the nuclear factor kappa B pathway.Another proposed epigenetic mechanism by which HCC may form is the aberrant silencing of tumor suppressor genes by DNA Methyltransferases.HDV antigens have also been associated with increased histone H3 acetylation of the clusterin promoter.This enhances the expression of clusterin in infected cells,increasing cell survival potential.Any contribution of HBV DNA integration with chromosomes of infected hepatocytes is not clear at this stage.The targeted inhibition of STAT3 and cyclophilin,and augmentation of peroxisome proliferatoractivated receptor γ have a potential therapeutic role in HCC.
