Gastric intestinal symptoms common among diabetic patients are often caused by intestinal motility abnormalities related to enteric neuropathy. It has recently been demonstrated that the nitrergic subpopulation of mye...Gastric intestinal symptoms common among diabetic patients are often caused by intestinal motility abnormalities related to enteric neuropathy. It has recently been demonstrated that the nitrergic subpopulation of myenteric neurons are especially susceptible to the development of diabetic neuropathy. Additionally, different susceptibility of nitrergic neurons located in different intestinal segments to diabetic damage and their different levels of responsiveness to insulin treatment have been revealed. These findings indicate the importance of the neuronal microenvironment in the pathogenesis of diabetic nitrergic neuropathy. The main focus of this review therefore was to summarize recent advances related to the diabetes-related selective nitrergic neuropathy and associated motility disturbances. Special attention was given to the findings on capillary endothelium and enteric glial cells. Growing evidence indicates that capillary endothelium adjacent to the myenteric ganglia and enteric glial cells surrounding them are determinative in establishing the ganglionic microenvironment. Additionally, recent advances in the development of new strategies to improve glycemic control in type 1 and type 2 diabetes mellitus are also considered in this review. Finally, looking to the future, the recent and promising results of metagenomics for the characterization of the gut microbiome in health and disease such as diabetes are highlighted.展开更多
AIM: To develop a new rat model we wanted to gain a better understanding of stricture formation in Crohn’s disease (CD).METHODS: Chronic colitis was induced locally by the administration of 2,4,6-trinitrob...AIM: To develop a new rat model we wanted to gain a better understanding of stricture formation in Crohn’s disease (CD).METHODS: Chronic colitis was induced locally by the administration of 2,4,6-trinitrobenzenesulfonic acid (TNBS). The relapsing inflammation characteristic to CD was mimicked by repeated TNBS treatments. Animals were randomly divided into control, once, twice and three times TNBS-treated groups. Control animals received an enema of saline. Tissue samples were taken from the strictured colonic segments and also adjacent proximally and distally to its 60, 90 or 120 d after the last TNBS or saline administrations. The frequency and macroscopic extent of the strictures were measured on digital photographs. The structural features of strictured gut wall were studied by light- and electron microscopy. Inflammation related alterations in TGF-beta 2 and 3, matrix metalloproteinases 9 (MMP9) and TIMP1 mRNA and protein expression were determined by quantitative real-time PCR and western blot analysis. The quantitative distribution of caspase 9 was determined by post-embedding immunohistochemistry.RESULTS: Intestinal strictures first appeared 60 d after TNBS treatments and the frequency of them increased up to day 120. From day 90 an intact lamina epithelialis, reversible thickening of lamina muscularis mucosae and irreversible thickening of the muscularis externa were demonstrated in the strictured colonic segments. Nevertheless the morphological signs of apoptosis were frequently seen and excess extracellular matrix deposition was recorded between smooth muscle cells (SMCs). Enhanced caspase 9 expression on day 90 in the SMCs and on day 120 also in myenteric neurons indicated the induction of apoptosis. The mRNA expression profile of TGF-betas after repeated TNBS doses was characteristic to CD, TGF-beta 2, but not TGF-beta 3 was up-regulated. Overexpression of MMP9 and down-regulation of TIMP1 were demonstrated. The progressive increase in the amount of MMP9 protein in the strictures was also obvious between days 90 and 120 but TIMP1 protein was practically undetectable at this time.CONCLUSION: These findings indicate that aligned structural and molecular changes in the gut wall rather than neuronal cell death play the primary role in stricture formation.展开更多
AIM:To establish a rat model suitable to investigate the repetitive relapsing inflammations(RRI)characteristic to Crohn’s disease.METHODS:Colitis was induced by 2,4,6-trinitrobenzenesulfonic acid(TNBS).RRI were mimic...AIM:To establish a rat model suitable to investigate the repetitive relapsing inflammations(RRI)characteristic to Crohn’s disease.METHODS:Colitis was induced by 2,4,6-trinitrobenzenesulfonic acid(TNBS).RRI were mimicked by repeating administrations of TNBS.Tissue samples were taken from control,once,twice and three times treated rats from the inflamed and adjacent non-inflamed colonic segments at different timepoints during the acute intestinal inflammation.The means of the ulcerated area were measured to evaluate the macroscopic mu-cosal damage.The density of myenteric neurons was determined on whole mounts by Hu C/Hu D immunohistochemistry.Heme oxygenase-1(HO-1)expression was evaluated by molecular biological techniques.RESULTS:TNBS-treated rats displayed severe colitis,but the mortality was negligible,and an increase of body weight was characteristic throughout the experimental period.The widespread loss of myenteric neurons,and marked but transient HO-1 up-regulation were demonstrated after the first TNBS administration.After repeated doses the length of the recovery time and extent of the ulcerous colonic segments were markedly decreased,and the neuronal loss was on a smaller scale and was limited to the inflamed area.HO-1 m RNA level was notably greater than after a single dose and overexpression was sustained throughout the timepoints examined.Nevertheless,the HO-1protein up-regulation after the second TNBS treatment proved to be transient.Following the third treatment HO-1 protein expression could not be detected.CONCLUSION:Experimentally provoked RRI may exert a protective preconditioning effect against the mucosal and neuronal damage.The persistent up-regulation of HO-1 m RNA expression may correlate with this.展开更多
AIM To investigate the intestinal segment-specific effects of diabetes and insulin replacement on the density of different subpopulations of submucous neurons. METHODS Ten weeks after the onset of type 1 diabetes samp...AIM To investigate the intestinal segment-specific effects of diabetes and insulin replacement on the density of different subpopulations of submucous neurons. METHODS Ten weeks after the onset of type 1 diabetes samples were taken from the duodenum, ileum and colon of streptozotocin-induce diabetic, insulin-treated diabetic and sex-and age-matched control rats. Whole-mount preparations of submucous plexus were prepared from the different gut segments for quantitative fluorescent immunohistochemistry. The following double-immunostainings were performed: neuronal nitric oxide synthase(n NOS) and Hu C/D, heme oxygenase(HO) 1 and peripherin, as well as HO2 and peripherin. The density of n NOS-, HO1-and HO2-immunoreactive(IR) neurons was determined as a percentage of the total number of submucous neurons. RESULTS The total number of submucous neurons and the proportion of n NOS-, HO1-and HO2-IR subpopulations were not affected in the duodenal ganglia of control, diabetic and insulin-treated rats. While the total neuronal number did not change in either the ileum or the colon, the density of nitrergic neurons exhibited a 2-and 3-fold increase in the diabetic ileum and colon, respectively, which was further enhanced after insulin replacement. The presence of HO1-and HO2-IR submucous neurons was robust in the colon of controls(38.4%-50.8%), whereas it was significantly lower in the small intestinal segments(0.0%-4.2%, P < 0.0001). Under pathophysiological conditions the only alteration detected was an increase in the ileum and a decrease in the colon of the proportion of HO-IR neurons in insulin-treated diabetic animals. CONCLUSION Diabetes and immediate insulin replacement induce the most pronounced region-specific alterations of n NOS-, HO1-and HO2-IR submucous neuronal density in the distal parts of the gut.展开更多
AIM:To study the cell-type specific subcellular distribution of the three isoforms of nitric oxide synthase(NOS) in the rat duodenum.METHODS:Postembedding immunoelectronmicroscopy was performed,in which primary antibo...AIM:To study the cell-type specific subcellular distribution of the three isoforms of nitric oxide synthase(NOS) in the rat duodenum.METHODS:Postembedding immunoelectronmicroscopy was performed,in which primary antibodies for neuronal NOS(nNOS),endothelial NOS(eNOS),and inducible NOS(iNOS),were visualized with protein A-gold-conjugated secondary antibodies.Stained ultrathin sections were examined and photographed with a Philips CM10 electron microscope equipped with a MEGAVIEW II camera.The specificity of the immunoreaction in all cases was assessed by omitting the primary antibodies in the labeling protocol and incubating the sections only in the protein A-gold conjugated secondary antibodies.RESULTS:Postembedding immunoelectronmicroscopy revealed the presence of nNOS,eNOS,and iNOS immunoreactivity in the myenteric neurons,the enteric smooth muscle cells,and the endothelium of capillariesrunning in the vicinity of the myenteric plexus of the rat duodenum.The cell type-specific distributions of the immunogold particles labeling the three different NOS isozymes were revealed.In the control experiments,in which the primary antiserum was omitted,virtually no postembedding gold particles were observed.CONCLUSION:This postembedding immunoelectronmicroscopic study provided the first evidence of celltype-specific differences in the subcellular distributions of NOS isoforms.展开更多
Diabetes,as a metabolic disorder,is accompanied with several gastrointestinal(GI)symptoms,like abdominal pain,gastroparesis,diarrhoea or constipation.Serious and complex enteric nervous system damage is confirmed in t...Diabetes,as a metabolic disorder,is accompanied with several gastrointestinal(GI)symptoms,like abdominal pain,gastroparesis,diarrhoea or constipation.Serious and complex enteric nervous system damage is confirmed in the background of these diabetic motility complaints.The anatomical length of the GI tract,as well as genetic,developmental,structural and functional differences between its segments contribute to the distinct,intestinal region-specific effects of hyperglycemia.These observations support and highlight the importance of a regional approach in diabetes-related enteric neuropathy.Intestinal large and microvessels are essential for the blood supply of enteric ganglia.Bidirectional morpho-functional linkage exists between enteric neurons and enteroglia,however,there is also a reciprocal communication between enteric neurons and immune cells on which intestinal microbial composition has crucial influence.From this point of view,it is more appropriate to say that enteric neurons partake in multidirectional communication and interact with these key players of the intestinal wall.These interplays may differ from segment to segment,thus,the microenvironment of enteric neurons could be considered strictly regional.The goal of this review is to summarize the main tissue components and molecular factors,such as enteric glia cells,interstitial cells of Cajal,gut vasculature,intestinal epithelium,gut microbiota,immune cells,enteroendocrine cells,prooxidants,antioxidant molecules and extracellular matrix,which create and determine a gut region-dependent neuronal environment in diabetes.展开更多
Chronic alcohol abuse damages nearly every organ in the body. The harmful effects of ethanol on thebrain, the liver and the pancreas are well documented. Although chronic alcohol consumption causes serious impairments...Chronic alcohol abuse damages nearly every organ in the body. The harmful effects of ethanol on thebrain, the liver and the pancreas are well documented. Although chronic alcohol consumption causes serious impairments also in the gastrointestinal tract like altered motility, mucosal damage, impaired absorption of nu-trients and inflammation, the effects of chronically consumed ethanol on the enteric nervous system are less detailed. While the nitrergic myenteric neurons play an essential role in the regulation of gastrointestinal peristalsis, it was hypothesised, that these neurons are the first targets of consumed ethanol or its metabolites generated in the different gastrointestinal segments. To reinforce this hypothesis the effects of ethanol on the gastrointestinal tract was investigated in different rodent models with quantitative immunohistochemistry, in vivo and in vitro motility measurements, western blot analysis, evaluation of nitric oxide synthase enzyme activity and bio-imaging of nitric oxide synthesis. These results suggest that chronic alcohol consumption did not result significant neural loss, but primarily impaired the nitrergic pathways in gut region-dependent way leading to disturbed gastrointestinal motility. The gut segment-specific differences in the effects of chronic alcohol consumption highlight the significance the ethanol-induced neuronal microenvironment involving oxidative stress and intestinal microbiota.展开更多
BACKGROUND The importance of the neuronal microenvironment has been recently highlighted in gut region-specific diabetic enteric neuropathy. Regionally distinct thickening of endothelial basement membrane(BM) of intes...BACKGROUND The importance of the neuronal microenvironment has been recently highlighted in gut region-specific diabetic enteric neuropathy. Regionally distinct thickening of endothelial basement membrane(BM) of intestinal capillaries supplying the myenteric ganglia coincide with neuronal damage in different intestinal segments. Accelerated synthesis of matrix molecules and reduced degradation of matrix components may also contribute to the imbalance of extracellular matrix dynamics resulting in BM thickening. Among the matrix degrading proteinases, matrix metalloproteinase 9(MMP9) and its tissue inhibitor(TIMP1) are essential in regulating extracellular matrix remodelling.AIM To evaluate the intestinal segment-specific effects of diabetes and insulin replacement on ganglionic BM thickness, MMP9 and TIMP1 expression.METHODS Ten weeks after the onset of hyperglycaemia gut segments were taken from the duodenum and ileum of streptozotocin-induced diabetic, insulin-treated diabetic and sex-and age-matched control rats. The thickness of BM surrounding myenteric ganglia was measured by electron microscopic morphometry. Wholemount preparations of myenteric plexus were prepared from the different gut regions for MMP9/TIMP1 double-labelling fluorescent immunohistochemistry. Post-embedding immunogold electron microscopy was applied on ultrathin sections to evaluate the MMP9 and TIMP1 expression in myenteric ganglia and their microenvironment from different gut segments and conditions. The MMP9 and TIMP1 messenger ribonucleic acid(m RNA) level was measured by quantitative polymerase chain reaction.RESULTS Ten weeks after the onset of hyperglycaemia, the ganglionic BM was significantly thickened in the diabetic ileum, while it remained intact in the duodenum. The immediate insulin treatment prevented the diabetes-related thickening of the BM surrounding the ileal myenteric ganglia. Quantification of particle density showed an increasing tendency for MMP9 and a decreasing tendency for TIMP1 from the proximal to the distal small intestine under control conditions. In the diabetic ileum, the number of MMP9-indicating gold particles decreased in myenteric ganglia, endothelial cells of capillaries and intestinal smooth muscle cells, however, it remained unchanged in all duodenal compartments. The MMP9/TIMP1 ratio was also decreased in ileal ganglia only. However, a marked segment-specific induction was revealed in MMP9 and TIMP1 at the m RNA levels.CONCLUSION These findings support that the regional decrease in MMP9 expression in myenteric ganglia and their microenvironment may contribute to extracellular matrix accumulation, resulting in a region-specific thickening of ganglionic BM.展开更多
BACKGROUND Cytokines are essential in autoimmune inflammatory processes that accompany type 1 diabetes.Tumor necrosis factor alpha plays a key role among others in modulating enteric neuroinflammation,however,it has a...BACKGROUND Cytokines are essential in autoimmune inflammatory processes that accompany type 1 diabetes.Tumor necrosis factor alpha plays a key role among others in modulating enteric neuroinflammation,however,it has a dual role in cell degeneration or survival depending on different TNFRs.In general,TNFR1 is believed to trigger apoptosis,while TNFR2 promotes cell regeneration.The importance of the neuronal microenvironment has been recently highlighted in gut region-specific diabetic enteric neuropathy,however,the expression and alterations of different TNFRs in the gastrointestinal tract has not been reported.AIM To investigate the TNFR1 and TNFR2 expression in myenteric ganglia and their environment in different intestinal segments of diabetic rats.METHODS Ten weeks after the onset of hyperglycemia,gut segments were taken from the duodenum,ileum and colon of streptozotocin-induced(60 mg/body weight kg i.p.)diabetic(n=17),insulin-treated diabetic(n=15)and sex-and age-matched control(n=15)rats.Myenteric plexus whole-mount preparations were prepared from different gut regions for TNFR1/HuCD or TNFR2/HuCD double-labeling fluorescent immunohistochemistry.TNFR1 and TNFR2 expression was evaluated by post-embedding immunogold electron microscopy on ultrathin sections of myenteric ganglia.TNFRs levels were measured by enzyme-linked immunosorbent assay in muscle/myenteric plexus-containing(MUSCLE-MP)tissue homogenates from different gut segments and experimental conditions.RESULTS A distinct region-dependent TNFRs expression was detected in controls.The density of TNFR1-labeling gold particles was lowest,while TNFR2 density was highest in duodenal ganglia and a decreased TNFRs expression from proximal to distal segments was observed in MUSCLE-MP homogenates.In diabetics,the TNFR2 density was only significantly altered in the duodenum with decrease in the ganglia(0.32±0.02 vs 0.45±0.04,P<0.05),while no significant changes in TNFR1 density was observed.In diabetic MUSCLE-MP homogenates,both TNFRs levels significantly decreased in the duodenum(TNFR1:4.06±0.65 vs 20.32±3.1,P<0.001;TNFR2:11.72±0.39 vs 15.91±1.04,P<0.01),which markedly influenced the TNFR2/TNFR1 proportion in both the ganglia and their muscular environment.Insulin treatment had controversial effects on TNFR expression.CONCLUSION Our findings show diabetes-related region-dependent changes in TNFR expression and suggest that TNFR2 is more affected than TNFR1 in myenteric ganglia in the duodenum of type 1 diabetic rats.展开更多
基金Supported by Hungarian National Grant Agency, Grant No. F46201 to Bagyánszki M
文摘Gastric intestinal symptoms common among diabetic patients are often caused by intestinal motility abnormalities related to enteric neuropathy. It has recently been demonstrated that the nitrergic subpopulation of myenteric neurons are especially susceptible to the development of diabetic neuropathy. Additionally, different susceptibility of nitrergic neurons located in different intestinal segments to diabetic damage and their different levels of responsiveness to insulin treatment have been revealed. These findings indicate the importance of the neuronal microenvironment in the pathogenesis of diabetic nitrergic neuropathy. The main focus of this review therefore was to summarize recent advances related to the diabetes-related selective nitrergic neuropathy and associated motility disturbances. Special attention was given to the findings on capillary endothelium and enteric glial cells. Growing evidence indicates that capillary endothelium adjacent to the myenteric ganglia and enteric glial cells surrounding them are determinative in establishing the ganglionic microenvironment. Additionally, recent advances in the development of new strategies to improve glycemic control in type 1 and type 2 diabetes mellitus are also considered in this review. Finally, looking to the future, the recent and promising results of metagenomics for the characterization of the gut microbiome in health and disease such as diabetes are highlighted.
基金Supported by Hungarian Scientific Research Fund,No.OTKA PD 108309 to Bódi Nthe János Bolyai Research Scholarship of the Hungarian Academy of Sciences to Bagyánszki M
文摘AIM: To develop a new rat model we wanted to gain a better understanding of stricture formation in Crohn’s disease (CD).METHODS: Chronic colitis was induced locally by the administration of 2,4,6-trinitrobenzenesulfonic acid (TNBS). The relapsing inflammation characteristic to CD was mimicked by repeated TNBS treatments. Animals were randomly divided into control, once, twice and three times TNBS-treated groups. Control animals received an enema of saline. Tissue samples were taken from the strictured colonic segments and also adjacent proximally and distally to its 60, 90 or 120 d after the last TNBS or saline administrations. The frequency and macroscopic extent of the strictures were measured on digital photographs. The structural features of strictured gut wall were studied by light- and electron microscopy. Inflammation related alterations in TGF-beta 2 and 3, matrix metalloproteinases 9 (MMP9) and TIMP1 mRNA and protein expression were determined by quantitative real-time PCR and western blot analysis. The quantitative distribution of caspase 9 was determined by post-embedding immunohistochemistry.RESULTS: Intestinal strictures first appeared 60 d after TNBS treatments and the frequency of them increased up to day 120. From day 90 an intact lamina epithelialis, reversible thickening of lamina muscularis mucosae and irreversible thickening of the muscularis externa were demonstrated in the strictured colonic segments. Nevertheless the morphological signs of apoptosis were frequently seen and excess extracellular matrix deposition was recorded between smooth muscle cells (SMCs). Enhanced caspase 9 expression on day 90 in the SMCs and on day 120 also in myenteric neurons indicated the induction of apoptosis. The mRNA expression profile of TGF-betas after repeated TNBS doses was characteristic to CD, TGF-beta 2, but not TGF-beta 3 was up-regulated. Overexpression of MMP9 and down-regulation of TIMP1 were demonstrated. The progressive increase in the amount of MMP9 protein in the strictures was also obvious between days 90 and 120 but TIMP1 protein was practically undetectable at this time.CONCLUSION: These findings indicate that aligned structural and molecular changes in the gut wall rather than neuronal cell death play the primary role in stricture formation.
基金Supported by Hungarian Scientific Research Fund,No.OTKA PD 108309(to Bódi N)European Union and the State of Hungaryco-financed by the European Social Fund in the frame-work of TáMOP 4.2.4.A/2-11/1-2012-0001"National Excellence Program"
文摘AIM:To establish a rat model suitable to investigate the repetitive relapsing inflammations(RRI)characteristic to Crohn’s disease.METHODS:Colitis was induced by 2,4,6-trinitrobenzenesulfonic acid(TNBS).RRI were mimicked by repeating administrations of TNBS.Tissue samples were taken from control,once,twice and three times treated rats from the inflamed and adjacent non-inflamed colonic segments at different timepoints during the acute intestinal inflammation.The means of the ulcerated area were measured to evaluate the macroscopic mu-cosal damage.The density of myenteric neurons was determined on whole mounts by Hu C/Hu D immunohistochemistry.Heme oxygenase-1(HO-1)expression was evaluated by molecular biological techniques.RESULTS:TNBS-treated rats displayed severe colitis,but the mortality was negligible,and an increase of body weight was characteristic throughout the experimental period.The widespread loss of myenteric neurons,and marked but transient HO-1 up-regulation were demonstrated after the first TNBS administration.After repeated doses the length of the recovery time and extent of the ulcerous colonic segments were markedly decreased,and the neuronal loss was on a smaller scale and was limited to the inflamed area.HO-1 m RNA level was notably greater than after a single dose and overexpression was sustained throughout the timepoints examined.Nevertheless,the HO-1protein up-regulation after the second TNBS treatment proved to be transient.Following the third treatment HO-1 protein expression could not be detected.CONCLUSION:Experimentally provoked RRI may exert a protective preconditioning effect against the mucosal and neuronal damage.The persistent up-regulation of HO-1 m RNA expression may correlate with this.
基金Supported by the Hungarian Scientific Research Fund,OTKA grant,No.PD 108309(Nikolett Bódi)by the János Bolyai Research Scholarship of the Hungarian Academy of Sciences(Mária Bagyánszki)by the Stipendium Hungaricum Scholarship,No.2015-SH-500041,Tempus Public Foundation(Lalitha Chandrakumar)
文摘AIM To investigate the intestinal segment-specific effects of diabetes and insulin replacement on the density of different subpopulations of submucous neurons. METHODS Ten weeks after the onset of type 1 diabetes samples were taken from the duodenum, ileum and colon of streptozotocin-induce diabetic, insulin-treated diabetic and sex-and age-matched control rats. Whole-mount preparations of submucous plexus were prepared from the different gut segments for quantitative fluorescent immunohistochemistry. The following double-immunostainings were performed: neuronal nitric oxide synthase(n NOS) and Hu C/D, heme oxygenase(HO) 1 and peripherin, as well as HO2 and peripherin. The density of n NOS-, HO1-and HO2-immunoreactive(IR) neurons was determined as a percentage of the total number of submucous neurons. RESULTS The total number of submucous neurons and the proportion of n NOS-, HO1-and HO2-IR subpopulations were not affected in the duodenal ganglia of control, diabetic and insulin-treated rats. While the total neuronal number did not change in either the ileum or the colon, the density of nitrergic neurons exhibited a 2-and 3-fold increase in the diabetic ileum and colon, respectively, which was further enhanced after insulin replacement. The presence of HO1-and HO2-IR submucous neurons was robust in the colon of controls(38.4%-50.8%), whereas it was significantly lower in the small intestinal segments(0.0%-4.2%, P < 0.0001). Under pathophysiological conditions the only alteration detected was an increase in the ileum and a decrease in the colon of the proportion of HO-IR neurons in insulin-treated diabetic animals. CONCLUSION Diabetes and immediate insulin replacement induce the most pronounced region-specific alterations of n NOS-, HO1-and HO2-IR submucous neuronal density in the distal parts of the gut.
基金Supported by Hungarian National Grant Agency, Grant#F46201to Bagyánszki M
文摘AIM:To study the cell-type specific subcellular distribution of the three isoforms of nitric oxide synthase(NOS) in the rat duodenum.METHODS:Postembedding immunoelectronmicroscopy was performed,in which primary antibodies for neuronal NOS(nNOS),endothelial NOS(eNOS),and inducible NOS(iNOS),were visualized with protein A-gold-conjugated secondary antibodies.Stained ultrathin sections were examined and photographed with a Philips CM10 electron microscope equipped with a MEGAVIEW II camera.The specificity of the immunoreaction in all cases was assessed by omitting the primary antibodies in the labeling protocol and incubating the sections only in the protein A-gold conjugated secondary antibodies.RESULTS:Postembedding immunoelectronmicroscopy revealed the presence of nNOS,eNOS,and iNOS immunoreactivity in the myenteric neurons,the enteric smooth muscle cells,and the endothelium of capillariesrunning in the vicinity of the myenteric plexus of the rat duodenum.The cell type-specific distributions of the immunogold particles labeling the three different NOS isozymes were revealed.In the control experiments,in which the primary antiserum was omitted,virtually no postembedding gold particles were observed.CONCLUSION:This postembedding immunoelectronmicroscopic study provided the first evidence of celltype-specific differences in the subcellular distributions of NOS isoforms.
基金Hungarian NKFIH Fund Project (N.B.),No.FK131789János Bolyai Research Scholarship of The Hungarian Academy of Sciences (N.B.)+1 种基金New National Excellence Program of The Ministry for Innovation and Technology from The Source of The National Research,Development and Innovation Fund (N.B.)No.úNKP-22-5
文摘Diabetes,as a metabolic disorder,is accompanied with several gastrointestinal(GI)symptoms,like abdominal pain,gastroparesis,diarrhoea or constipation.Serious and complex enteric nervous system damage is confirmed in the background of these diabetic motility complaints.The anatomical length of the GI tract,as well as genetic,developmental,structural and functional differences between its segments contribute to the distinct,intestinal region-specific effects of hyperglycemia.These observations support and highlight the importance of a regional approach in diabetes-related enteric neuropathy.Intestinal large and microvessels are essential for the blood supply of enteric ganglia.Bidirectional morpho-functional linkage exists between enteric neurons and enteroglia,however,there is also a reciprocal communication between enteric neurons and immune cells on which intestinal microbial composition has crucial influence.From this point of view,it is more appropriate to say that enteric neurons partake in multidirectional communication and interact with these key players of the intestinal wall.These interplays may differ from segment to segment,thus,the microenvironment of enteric neurons could be considered strictly regional.The goal of this review is to summarize the main tissue components and molecular factors,such as enteric glia cells,interstitial cells of Cajal,gut vasculature,intestinal epithelium,gut microbiota,immune cells,enteroendocrine cells,prooxidants,antioxidant molecules and extracellular matrix,which create and determine a gut region-dependent neuronal environment in diabetes.
基金Supported by The János Bolyai Research Scholarship of the Hungarian Academy of Sciences(Mária Bagyánszki)by the Hungarian Scientific Research Fund,OTKA grant PD 108309(Nikolett Bódi)
文摘Chronic alcohol abuse damages nearly every organ in the body. The harmful effects of ethanol on thebrain, the liver and the pancreas are well documented. Although chronic alcohol consumption causes serious impairments also in the gastrointestinal tract like altered motility, mucosal damage, impaired absorption of nu-trients and inflammation, the effects of chronically consumed ethanol on the enteric nervous system are less detailed. While the nitrergic myenteric neurons play an essential role in the regulation of gastrointestinal peristalsis, it was hypothesised, that these neurons are the first targets of consumed ethanol or its metabolites generated in the different gastrointestinal segments. To reinforce this hypothesis the effects of ethanol on the gastrointestinal tract was investigated in different rodent models with quantitative immunohistochemistry, in vivo and in vitro motility measurements, western blot analysis, evaluation of nitric oxide synthase enzyme activity and bio-imaging of nitric oxide synthesis. These results suggest that chronic alcohol consumption did not result significant neural loss, but primarily impaired the nitrergic pathways in gut region-dependent way leading to disturbed gastrointestinal motility. The gut segment-specific differences in the effects of chronic alcohol consumption highlight the significance the ethanol-induced neuronal microenvironment involving oxidative stress and intestinal microbiota.
基金European Union and the Hungarian Government in the framework,No.EFOP-3.6.1-16-2016-00008Hungarian NKFIH fund project,No.FK131789(to Bódi N)+1 种基金János Bolyai Research Scholarship of the Hungarian Academy of Sciences(to Bódi N)and New National Excellence Program of the Ministry for Innovation and Technology from the source of the National Research,Development and Innovation Fund,No.ÚNKP-20-5(to Bódi N).
文摘BACKGROUND The importance of the neuronal microenvironment has been recently highlighted in gut region-specific diabetic enteric neuropathy. Regionally distinct thickening of endothelial basement membrane(BM) of intestinal capillaries supplying the myenteric ganglia coincide with neuronal damage in different intestinal segments. Accelerated synthesis of matrix molecules and reduced degradation of matrix components may also contribute to the imbalance of extracellular matrix dynamics resulting in BM thickening. Among the matrix degrading proteinases, matrix metalloproteinase 9(MMP9) and its tissue inhibitor(TIMP1) are essential in regulating extracellular matrix remodelling.AIM To evaluate the intestinal segment-specific effects of diabetes and insulin replacement on ganglionic BM thickness, MMP9 and TIMP1 expression.METHODS Ten weeks after the onset of hyperglycaemia gut segments were taken from the duodenum and ileum of streptozotocin-induced diabetic, insulin-treated diabetic and sex-and age-matched control rats. The thickness of BM surrounding myenteric ganglia was measured by electron microscopic morphometry. Wholemount preparations of myenteric plexus were prepared from the different gut regions for MMP9/TIMP1 double-labelling fluorescent immunohistochemistry. Post-embedding immunogold electron microscopy was applied on ultrathin sections to evaluate the MMP9 and TIMP1 expression in myenteric ganglia and their microenvironment from different gut segments and conditions. The MMP9 and TIMP1 messenger ribonucleic acid(m RNA) level was measured by quantitative polymerase chain reaction.RESULTS Ten weeks after the onset of hyperglycaemia, the ganglionic BM was significantly thickened in the diabetic ileum, while it remained intact in the duodenum. The immediate insulin treatment prevented the diabetes-related thickening of the BM surrounding the ileal myenteric ganglia. Quantification of particle density showed an increasing tendency for MMP9 and a decreasing tendency for TIMP1 from the proximal to the distal small intestine under control conditions. In the diabetic ileum, the number of MMP9-indicating gold particles decreased in myenteric ganglia, endothelial cells of capillaries and intestinal smooth muscle cells, however, it remained unchanged in all duodenal compartments. The MMP9/TIMP1 ratio was also decreased in ileal ganglia only. However, a marked segment-specific induction was revealed in MMP9 and TIMP1 at the m RNA levels.CONCLUSION These findings support that the regional decrease in MMP9 expression in myenteric ganglia and their microenvironment may contribute to extracellular matrix accumulation, resulting in a region-specific thickening of ganglionic BM.
基金Supported by Hungarian National Research,Development and Innovation Fund Projects,No.GINOP-2.3.3-15-2016-00006Hungarian NKFIH Fund Project,No.FK131789(to Bódi N)+2 种基金János Bolyai Research Scholarship of the Hungarian Academy of Sciences(to Bódi N)ÚNKP-21-5-New National Excellence Program of the Ministry for Innovation and Technology from the source of the National Research,Development and Innovation Fund(to Bódi N)Gedeon Richter Plc Centenary Foundation(to Bódi N).
文摘BACKGROUND Cytokines are essential in autoimmune inflammatory processes that accompany type 1 diabetes.Tumor necrosis factor alpha plays a key role among others in modulating enteric neuroinflammation,however,it has a dual role in cell degeneration or survival depending on different TNFRs.In general,TNFR1 is believed to trigger apoptosis,while TNFR2 promotes cell regeneration.The importance of the neuronal microenvironment has been recently highlighted in gut region-specific diabetic enteric neuropathy,however,the expression and alterations of different TNFRs in the gastrointestinal tract has not been reported.AIM To investigate the TNFR1 and TNFR2 expression in myenteric ganglia and their environment in different intestinal segments of diabetic rats.METHODS Ten weeks after the onset of hyperglycemia,gut segments were taken from the duodenum,ileum and colon of streptozotocin-induced(60 mg/body weight kg i.p.)diabetic(n=17),insulin-treated diabetic(n=15)and sex-and age-matched control(n=15)rats.Myenteric plexus whole-mount preparations were prepared from different gut regions for TNFR1/HuCD or TNFR2/HuCD double-labeling fluorescent immunohistochemistry.TNFR1 and TNFR2 expression was evaluated by post-embedding immunogold electron microscopy on ultrathin sections of myenteric ganglia.TNFRs levels were measured by enzyme-linked immunosorbent assay in muscle/myenteric plexus-containing(MUSCLE-MP)tissue homogenates from different gut segments and experimental conditions.RESULTS A distinct region-dependent TNFRs expression was detected in controls.The density of TNFR1-labeling gold particles was lowest,while TNFR2 density was highest in duodenal ganglia and a decreased TNFRs expression from proximal to distal segments was observed in MUSCLE-MP homogenates.In diabetics,the TNFR2 density was only significantly altered in the duodenum with decrease in the ganglia(0.32±0.02 vs 0.45±0.04,P<0.05),while no significant changes in TNFR1 density was observed.In diabetic MUSCLE-MP homogenates,both TNFRs levels significantly decreased in the duodenum(TNFR1:4.06±0.65 vs 20.32±3.1,P<0.001;TNFR2:11.72±0.39 vs 15.91±1.04,P<0.01),which markedly influenced the TNFR2/TNFR1 proportion in both the ganglia and their muscular environment.Insulin treatment had controversial effects on TNFR expression.CONCLUSION Our findings show diabetes-related region-dependent changes in TNFR expression and suggest that TNFR2 is more affected than TNFR1 in myenteric ganglia in the duodenum of type 1 diabetic rats.
