The gut microbiota is mainly composed of a diverse population of commensal bacterial species and plays a pivotal role in the maintenance of intestinal homeostasis, immune modulation and metabolism. The influence of the gut microbiota on solid organ transplantation has recently been recognized. In fact, several studies indicated that acute and chronic allograft rejection in small bowel transplantation (SBT) is closely associated with the alterations in microbial patterns in the gut. In this review, we focused on the recent findings regarding alterations in the microbiota following SBTand the potential roles of these alterations in the development of acute and chronic allograft rejection. We also reviewed important advances with respect to the interplays between the microbiota and host immune systems in SBT. Furthermore, we explored the potential of the gut microbiota as a microbial marker and/or therapeutic target for the predication and intervention of allograft rejection and chronic dysfunction. Given that current research on the gut microbiota has become increasingly sophisticated and comprehensive, large cohort studies employing metagenomic analysis and multivariate linkage should be designed for the characterization of host-microbe interaction and causality between microbiota alterations and clinical outcomes in SBT. The findings are expected to provide valuable insights into the role of gut microbiota in the development of allograft rejection and other transplant-related complications and introduce novel therapeutic targets and treatment approaches in clinical practice.
Biomarkers ; Gastrointestinal Microbiome ; Graft Rejection ; immunology ; Humans ; Immunity, Mucosal ; Intestine, Small ; microbiology ; transplantation ; Metagenomics ; Transplantation Tolerance ; immunology

OBJECTIVETo observe the ultrastructural change of the route of gut bacterial translocation in a rat with spinal cord injury (SCI).

METHODSForty Wistar rats were divided into the following groups: control group and 3 SCI groups (10 in each group). The rats in the SCI groups were established SCI model at 24 h, 48 h, and 72 h after SCI. Small intestine mucous membrane tissue was identified and assayed by transmission electron microscope, scanning electron microscope and immunofluorescence microscopy.

RESULTSSmall intestine mucous membrane tissue in control group was not damaged significantly, but those in SCI groups were damaged significantly. Proliferation bacteria in gut lumen attached on microvilli. The extracellular bacteria torn the intestinal barrier and perforated into the small intestinal mucosal epithelial cell. The bacteria and a lot of particles of the seriously damaged region penetrated into the lymphatic system and the blood system directly. Some bacteria were internalized into the goblet cell through the apical granule. Some bacteria and particles perforated into the submucosa of the M cell running the long axis of M cells through the tight junctions. In the microcirculation of mucosa, the bacteria that had already broken through the microvilli into blood circulation swim accompanying with erythrocytes.

CONCLUSIONThe routes of bacterial translocation interact and format a vicious circle. At early step, the transcellular pathway of bacterial translocation is major. Following with the destroyed small intestine mucous, the routes of bacterial translocation through the lymphatic system and the blood system become direct pathways. The goblet cell-dendritic cell and M cell pathway also play an important role in the bacterial translocation.

Animals ; Bacteria ; Bacterial Translocation ; Epithelial Cells ; microbiology ; Goblet Cells ; microbiology ; Intestinal Mucosa ; microbiology ; pathology ; ultrastructure ; Intestine, Small ; microbiology ; pathology ; ultrastructure ; Microvilli ; microbiology ; Rats ; Rats, Wistar ; Spinal Cord Injuries ; microbiology

Radiation therapy is an important treatment modality for abdominal or pelvic cancer, but there is a common and serious complication such as radiation-induced enteritis. Probiotics is reported to have positive effects against radiation-induced enteropathy. In this study, morphological changes of bowel mucosa were analyzed in rats to presume the effect of probiotics on radiation-induced enteritis and its correlation with radiation dose. A total of 48 adult male Sprague-Dawley rats were randomly assigned to two groups and received a solution containing 1.0x108 colony-forming units of Lactiobacillus acidophilus or water once daily for 10 days. Each of two groups was divided into three subgroups and abdomino-pelvic area of each subgroup was irradiated with 10, 15, and 20 Gy, respectively on the seventh day of feeding the solutions. All rats were sacrificed 3 days after irradiation and the mucosal thickness and villus height of jejunum, ileum and colon were measured. The morphological parameters of the small intestine represented significant differences between two solution groups irradiated 10 or 15 Gy, except for villus height of jejunum in 15 Gy-subgroup (P=0.065). There was no significant morphometric difference between two groups irradiated with 20 Gy of radiation. Probiotics appear to be effective for the morphological shortening of small intestinal mucosa damaged by radiation less than or equal to 15 Gy.
Animals ; Colon/pathology ; Disease Models, Animal ; Enteritis/pathology/prevention & control ; Ileum/pathology ; Intestinal Mucosa/microbiology/*radiation effects ; Intestine, Small ; Jejunum/pathology ; Lactobacillus acidophilus/*metabolism ; Male ; Probiotics/administration & dosage/*pharmacology ; Radiation Injuries, Experimental/*prevention & control/therapy ; Radiation Protection/*methods ; Random Allocation ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo investigate the initial changes in the gut microenvironment that accompany intestinal endotoxemia related to alcoholic fatty liver disease (ALD) in order to explore the potential initiating factors and to observe the effect of probiotic therapy on these factors.

METHODSFifty Sprague-Dawley male rats were randomly divided into an ALD model group (alcoholic intragastric administration), an intervention group (ALD with probiotic intragastric administration), and a control group (physiological saline intragastric administration). Histological changes of the liver were evaluated using hematoxylin-eosin staining and light microscopy. Serum alanine aminotransferase (ALT), aspartate aminotransferase (AST) and triglycerides (TG), and plasma endotoxin and coli bacillus were determined. The structural integrity of intestinal mucosa and tight junctions were observed by transmission electron microscopy. Occludin protein expression in intestinal epithelial cells was detected by immunohistochemistry.

RESULTSAfter four weeks, the three groups showed significant differences in the plasma endotoxin levels [control: (0.67+/-0.14) pg/ml, model: (4.42+/-1.28) pg/ml, and intervention: (2.88+/-0.83) pg/ml; F = 27.288, P = 0.000] and numbers of Escherichia coli [control: (2.31+/-0.39) lg3/ml, model: (3.23+/-0.41) lg3/ml, and intervention: (2.24+/-0.44) lg3/ml; F = 10.692, P = 0.001]. The plasma endotoxin level and E. coli number were significantly higher in the model group than in the control group and the intervention group (all P less than 0.05). The three groups showed no significant differences in the levels of ALT, AST, and TG at four weeks. After eight weeks, however, all three serum markers were significantly different between the three groups [ALT: control: (62.33+/-7.12) U/L, model: (95.50+/-8.73) U/L, and intervention: (81.33+/-6.19) U/L; F = 18.051, P = 0.000]; [AST: control: (90.50+/-10.67) U/L, model: (130.00+/-14.91) U/L, and intervention: (110.33+/-7.26) U/L; F = 30.170, P = 0.000]; [TG: control: (0.84+/-0.84) mmol/L, model: (1.40+/-0.17) mmol/L, and intervention: (1.10+/-0.17) mmol/L; F = 10.592, P = 0.001]. In addition, the three groups showed significant differences in E. coli number [control: (2.23+/-0.46) lg3/ml, model: (4.81+/-0.29) lg3/ml, and intervention: (3.61+/-0.50) lg3/ml; F = 23.579, P = 0.000] and plasma endotoxin level [control: (0.52+/-0.21) pg/ml, model: (12.46+/-2.61) pg/ml, intervention: (6.83+/-1.74) pg/ml; F = 30.731, P = 0.000]. The levels of ALT, AST, TG and endotoxin, and the number of E. coli were all significantly higher in the model group than in the control group and the intervention group (all P less than 0.05). Small intestinal epithelial cell structural failure was more apparent and intercellular gaps more broad after eight weeks than after four weeks for all three groups. However, the intervention group showed clearer cell connection structures and less extensive cell gap broadening than the model group at eight weeks. After eight weeks, the occludin protein had become significantly down-regulated and distributed in a non-continuous pattern in the model group, as compared with the control group. However, the occludin protein expression was higher in intervention group than in the model group.

CONCLUSIONIntestinal endotoxemia related to perturbations in the microenvironment occurs in the early phase of ALD, and the increased intestinal permeability appears to be the initial factor of elevated plasma endotoxin, which may lead to liver damage. Probiotic therapy can reduced plasma endotoxin levels and postpone ALD progression by altering the composition of the gut microbiota and up-regulating expression of the occludin protein in intestinal epithelial cells.

Alanine Transaminase ; blood ; Animals ; Aspartate Aminotransferases ; blood ; Endotoxins ; blood ; Escherichia coli ; isolation & purification ; Fatty Liver, Alcoholic ; microbiology ; therapy ; Intestinal Mucosa ; metabolism ; microbiology ; Intestine, Small ; metabolism ; microbiology ; Male ; Occludin ; metabolism ; Probiotics ; therapeutic use ; Rats ; Rats, Sprague-Dawley ; Triglycerides ; blood

OBJECTIVETo evaluate the protective effect of N-acetylcysteine (NAC) on the intestinal barrier dysfunction in rats after extensive abdominal radiation with X ray.

METHODSTwenty-four Spraque-Dawley male rats were divided into normal control group (n=8), radiation group (n=8), and radiation+NAC group (300 mg/kg) (n=8). Radiation injury was induced by X ray with a single dose of 10 Gy. NAC was administered from 4 days before irradiation to 3 days after radiation. Three days after radiation, all the rats were euthanized. The terminal ileum was collected for crypt survival assay and ileal villi count. The tissue samples from mesenteric lymph nodes (MLN), spleen, and liver were harvested under sterile conditions for microbiological analysis and ileum samples were harvested for biochemical analysis. The blood levels of D-lactate, endotoxin and diamine oxidase (DAO) and the ileum samples levels of nitric oxide(NO) were also measured.

RESULTSRats in radiation+NAC group had a higher survival rate of intestinal crypt [(76.84+/-4.82)% vs (49.64+/-5.48)%, P<0.01], higher intestinal villus count [(8.56+/-0.68)/mm vs (4.02+/-0.54)/mm, P<0.01], lower NO concentration [(0.48+/-0.12) mumol/g vs (0.88+/-0.16) mumol/g, P<0.01], lower levels of D-lactate, endotoxin and DAO (P<0.05 or P<0.01), and significantly decreased enteric bacteria cultured from mesenteric lymph nodes and other tissues as compared with the radiation group (P<0.05 or P<0.01).

CONCLUSIONNAC protects the small intestine from radiation-induced injury maybe through the inhibition of NO in rats.

Acetylcysteine ; pharmacology ; Animals ; Dose-Response Relationship, Radiation ; Intestinal Mucosa ; drug effects ; metabolism ; microbiology ; Intestine, Small ; drug effects ; Male ; Nitric Oxide ; analysis ; Radiation Injuries ; metabolism ; physiopathology ; Rats ; Rats, Sprague-Dawley ; X-Rays ; adverse effects

Adult ; Female ; Gases ; Humans ; Intestine, Small ; metabolism ; microbiology ; physiology ; Liver Cirrhosis ; metabolism ; microbiology ; Male ; Middle Aged

BACKGROUND/AIMS: Lactulose breath test (LBT) has been used as a presumptive surrogate marker for small intestinal bacterial overgrowth (SIBO). However, recent reports suggest that abnormal LBT cannot discriminate patients with irritable bowel syndrome (IBS) from the control. Thus, the aim of this study was to evaluate the usefulness of LBT in IBS. METHODS: LBT from 76 IBS patients, 70 functional bowel disorders (FBD), and 40 controls were examined. LBT was considered positive if (1) baseline breath hydrogen (H2) >20 parts per million (ppm) or rise of breath H2 >20 ppm above the baseline in <90 mins, or (2) baseline breath methane (CH4) >10 ppm or rise of breath CH4 >10 ppm above the baseline in <90 mins. The subjects were categorized into predominant hydrogen producers (PHP), predominant methane producers (PMP), combined producer, and both negative group based on LBT. RESULTS: The rate of abnormal LBT in the IBS, FBD, and control group were 44.7%, 41.4%, and 40.0% respectively without significant differences. The rate of PHP or PMP was not significantly different among the IBS, FBD, and control group. When clinical characteristics were analyzed in IBS and FBD according to LBT types, IBS subtypes and symptoms were not significantly different. CONCLUSIONS: LBT was not useful to discriminate IBS/FBD patients from the control. The assessment of SIBO by LBT in IBS should be revalidated in the future.
Adult ; Breath Tests/*methods ; Diagnosis, Differential ; Female ; Humans ; Intestine, Small/*microbiology ; Irritable Bowel Syndrome/*diagnosis ; Lactulose/*diagnostic use ; Male ; Middle Aged ; Predictive Value of Tests

The presence of galectin-3 was immunohistochemically quantified in bovine intestines infected with paratuberculosis (Johne's disease) to determine whether galectin-3 was involved in the formation of granulation tissue associated with the disease. Mycobacterium avium subsp. paratuberculosis infection was histochemically confirmed using Ziehl-Neelsen staining and molecularly diagnosed through rpoB DNA sequencing. Galectin-3 was detected in the majority of inflammatory cells, possibly macrophages, in the granulomatous lesions within affected tissues, including the ileum. These findings suggest that galectin-3 is associated with the formation of chronic granulation tissues in bovine paratuberculosis, probably through cell adhesion and anti-apoptosis mechanisms.
Animals ; Cattle ; Cattle Diseases/*pathology ; Chronic Disease ; Galectin 3/*metabolism ; Immunohistochemistry ; Intestine, Small/microbiology/*pathology ; Mycobacterium avium subsp. paratuberculosis/growth & development/isolation & purification ; Paratuberculosis/*pathology ; RNA Polymerase II/genetics

OBJECTIVETo observe the pathological changes of the intestinal mucosa in rats with severe abdominal infection.

METHODA total of 60 SD rats were divided randomly into control group and experimental group (n=30), and in the latter group, the rats underwent cecal ligation and puncture (CLP) while those in the former had only laparotomy. The jejunum and ileum were sampled on postoperative days 1, 2 and 4 for optical and electron microscopic observations. The positivity rate of blood bacterial culture and plasma level of endotoxin were determined in the rats.

RESULTSNo abnormal changes were observed with either optical and electron microscope in the small intestinal mucous membrane of rats in the control group, but in rats of the experimental group, microscopic examination revealed interstitial edema, vascular engorgement and neutrophil infiltration in the small intestine mucous membrane and the submucosa, and electron microscopy demonstrated loose and disorderly arrangement of the microvilli of the intestinal epithelium. Plasma endotoxin level in rats in the experimental group was 5- to 12-fold higher than that in the control group. The positivity rates of blood bacterial culture were 20%, 30% and 10% on postoperative days 1, 2 and 4 respectively in the experimental group, but were all zero in the control group.

CONCLUSIONPathologic lesions in the intestinal mucosa occur during the early stage of severe abdominal infection in rats as the result of bacteria and endotoxin translocation.

Animals ; Bacteria ; isolation & purification ; Bacterial Infections ; blood ; microbiology ; pathology ; Bacterial Translocation ; Cecum ; Endotoxins ; blood ; Female ; Intestinal Diseases ; etiology ; microbiology ; pathology ; Intestinal Mucosa ; microbiology ; pathology ; ultrastructure ; Intestine, Small ; microbiology ; pathology ; Ligation ; adverse effects ; Male ; Microscopy, Electron ; Punctures ; adverse effects ; Random Allocation ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo study the effects and mechanisms of Jianpi Liqi Huoxue Decoction (JLHD) in anti-alcoholic liver injury (ALI) through the pathological relation of ALI with changes of intestinal permeability and endotoxin leakage.

METHODSThe liver injury model induced by Lieber-DeCarli alcoholic forage was established. Altogether 42 male SD rats were randomly divided into 4 groups, the normal group (n=6), the control group fed with non-alcohol diet (n=12), the model group fed with alcoholic diet (n=12) and the treated group fed with alcoholic diet and treated with JLHD (n=12). The medicine or distilled water was administered by gavage from the 3rd week to the end of the 6th week. Then after fasting for 5 h all the rats except those in the normal group were given lipopolysaccharide (LPS) 10 mg/kg by gavage, and the blood plasma from portal vein, serum from inferior cava vein as well as tissues of liver and intestine were prepared for detection of plasma LPS level in the portal vein to observe the change of intestinal permeability through LPS content in portal vein blood plasma, the pathological and ultrastructural changes of the small intestine by HE staining, the pathological change of liver and triglyceride (TG) content and gamma glutamyl transpeptidase (GGT) activity in liver, the changes of serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activity, and plasma tumor necrosis factor-alpha (TNF-alpha) level.

RESULTSIn rats after modeling, there were obvious fatty degeneration, significant increase of hepatic TG content and GGT activity, serum ALT and AST activity, as well as plasma TNF-alpha level, with high plasma LPS level indicating increased intestinal permeability, and seriously injured mucosa microvilla of small intestine. However, all the above abnormal changes were milder in the treated group than those in the model group. Meanwhile, the TNF-alpha content, endotoxin level and ALT activity were found to be positively correlated.

CONCLUSIONJLHD could alleviate liver injury through inhibiting the alcohol induced increased intestinal permeability and lessening endotoxin leakage.

Animals ; Drugs, Chinese Herbal ; therapeutic use ; Endotoxins ; metabolism ; Intestinal Mucosa ; metabolism ; Intestine, Small ; microbiology ; pathology ; Liver Diseases, Alcoholic ; drug therapy ; microbiology ; pathology ; Male ; Permeability ; Phytotherapy ; Random Allocation ; Rats ; Rats, Sprague-Dawley