Multiple factors are involved in the etiology of cardiovascular disease(CVD). Pathological changes occur in a variety of cell types long before symptoms become apparent and diagnosis is made. Dysregulation of physiolo...Multiple factors are involved in the etiology of cardiovascular disease(CVD). Pathological changes occur in a variety of cell types long before symptoms become apparent and diagnosis is made. Dysregulation of physiological functions are associated with the activation of immune cells,leading to local and finally systemic inflammation that is characterized by production of high levels of reactive oxygen species(ROS). Patients suffering from inflammatory diseases often present with diminished levels of antioxidants either due to insufficient dietary intake or,and even more likely,due to increased demand in situations of overwhelming ROS production by activated immune effector cells like macrophages. Antioxidants are suggested to beneficially interfere with diseases-related oxidative stress,however the interplay of endogenous and exogenous antioxidants with the overall redox system is complex. Moreover,molecular mechanisms underlying oxidative stress in CVD are not fully elucidated. Metabolic dybalances are suggested to play a major role in disease onset and progression. Several central signalingpathways involved in the regulation of immunological,metabolic and endothelial function are regulated in a redox-sensitive manner. During cellular immune response,interferon γ-dependent pathways are activated such as tryptophan breakdown by the enzyme indoleamine 2,3-dioxygenase(IDO) in monocyte-derived macrophages,fibroblasts,endothelial and epithelial cells. Neopterin,a marker of oxidative stress and immune activation is produced by GTP-cyclohydrolase Ⅰ in macrophages and dendritic cells. Nitric oxide synthase(NOS) is induced in several cell types to generate nitric oxide(NO). NO,despite its low reactivity,is a potent antioxidant involved in the regulation of the vasomotor tone and of immunomodulatory signaling pathways. NO inhibits the expression and function of IDO. Function of NOS requires the cofactor tetrahydrobiopterin(BH4),which is produced in humans primarily by fibroblasts and endothelial cells. Highly toxic per展开更多
Irritable bowel syndrome(IBS) is an extremely prevalent but poorly understood gastrointestinal disorder. Consequently, there are no clear diagnostic markers to help diagnose the disorder and treatment options are limi...Irritable bowel syndrome(IBS) is an extremely prevalent but poorly understood gastrointestinal disorder. Consequently, there are no clear diagnostic markers to help diagnose the disorder and treatment options are limited to management of the symptoms. The concept of a dysregulated gut-brain axis has been adopted as a suitable model for the disorder. The gut microbiome may play an important role in the onset and exacerbation of symptoms in the disorder and has been extensively studied in this context. Although a causal role cannot yet be inferred from the clinical studies which have attempted to characterise the gut microbiota in IBS, they do confirm alterations in both community stability and diversity. Moreover, it has been reliably demonstrated that manipulation of the microbiota can influence the key symptoms, including abdominal pain and bowel habit, and other prominent features of IBS. A variety of strategies have been taken to study these interactions, including probiotics, antibiotics, faecal transplantations and the use of germ-free animals. There are clear mechanisms through which the microbiota can produce these effects, both humoral and neural. Taken together, these findings firmly establish the microbiota as a critical node in the gut-brain axis and one which is amenable to therapeutic interventions.展开更多
文摘Multiple factors are involved in the etiology of cardiovascular disease(CVD). Pathological changes occur in a variety of cell types long before symptoms become apparent and diagnosis is made. Dysregulation of physiological functions are associated with the activation of immune cells,leading to local and finally systemic inflammation that is characterized by production of high levels of reactive oxygen species(ROS). Patients suffering from inflammatory diseases often present with diminished levels of antioxidants either due to insufficient dietary intake or,and even more likely,due to increased demand in situations of overwhelming ROS production by activated immune effector cells like macrophages. Antioxidants are suggested to beneficially interfere with diseases-related oxidative stress,however the interplay of endogenous and exogenous antioxidants with the overall redox system is complex. Moreover,molecular mechanisms underlying oxidative stress in CVD are not fully elucidated. Metabolic dybalances are suggested to play a major role in disease onset and progression. Several central signalingpathways involved in the regulation of immunological,metabolic and endothelial function are regulated in a redox-sensitive manner. During cellular immune response,interferon γ-dependent pathways are activated such as tryptophan breakdown by the enzyme indoleamine 2,3-dioxygenase(IDO) in monocyte-derived macrophages,fibroblasts,endothelial and epithelial cells. Neopterin,a marker of oxidative stress and immune activation is produced by GTP-cyclohydrolase Ⅰ in macrophages and dendritic cells. Nitric oxide synthase(NOS) is induced in several cell types to generate nitric oxide(NO). NO,despite its low reactivity,is a potent antioxidant involved in the regulation of the vasomotor tone and of immunomodulatory signaling pathways. NO inhibits the expression and function of IDO. Function of NOS requires the cofactor tetrahydrobiopterin(BH4),which is produced in humans primarily by fibroblasts and endothelial cells. Highly toxic per
基金Supported by Science Foundation Ireland,No.SFI/12/RC/2272,No.02/CE/B124,No.07/CE/B1368Health Research Board No.HRA_POR/2011/23Brain and Behaviour Research Foundation No.20771
文摘Irritable bowel syndrome(IBS) is an extremely prevalent but poorly understood gastrointestinal disorder. Consequently, there are no clear diagnostic markers to help diagnose the disorder and treatment options are limited to management of the symptoms. The concept of a dysregulated gut-brain axis has been adopted as a suitable model for the disorder. The gut microbiome may play an important role in the onset and exacerbation of symptoms in the disorder and has been extensively studied in this context. Although a causal role cannot yet be inferred from the clinical studies which have attempted to characterise the gut microbiota in IBS, they do confirm alterations in both community stability and diversity. Moreover, it has been reliably demonstrated that manipulation of the microbiota can influence the key symptoms, including abdominal pain and bowel habit, and other prominent features of IBS. A variety of strategies have been taken to study these interactions, including probiotics, antibiotics, faecal transplantations and the use of germ-free animals. There are clear mechanisms through which the microbiota can produce these effects, both humoral and neural. Taken together, these findings firmly establish the microbiota as a critical node in the gut-brain axis and one which is amenable to therapeutic interventions.
