Toxicant-associated steatohepatitis in vinyl chloride workers.

UNLABELLED: Although nonalcoholic steatohepatitis (NASH) is typically associated with obesity, it has also been reported to occur in lean individuals exposed to industrial chemicals. Occupational exposure to vinyl chloride (VC) is a well-documented risk factor for hemangiosarcoma, but has not previously been associated with steatohepatitis. Here we evaluate liver biopsies from 25 nonobese, highly exposed VC workers for steatohepatitis. Next, we evaluate associated metabolic and cytokine abnormalities in affected workers controlled by 26 chemical workers with no to minimal VC exposures, and 11 unexposed, healthy volunteers. Among highly exposed VC workers the prevalence of steatohepatitis was 80%. Of these, 55% had fibrosis and four had hemangiosarcoma. We have coined the term toxicant-associated steatohepatitis (TASH) to describe this condition, which was not explained by obesity or alcohol. Although mean serum transaminases were normal in TASH, total cytokeratin 18, but not the caspase-cleaved fragment, was elevated. Despite the absence of obesity, workers with TASH had insulin resistance with reduced adiponectin levels. TASH was also associated with markedly elevated serum tumor necrosis factor alpha and interleukins 1beta, 6, and 8. Serum antioxidant activity was reduced in TASH. CONCLUSION: TASH occurred frequently in these nonobese VC workers with high cumulative exposures and normal liver enzymes. Elevated total cytokeratin 18 suggested the presence of necrotic cell death in TASH and may be a useful serologic biomarker. TASH was further characterized by insulin resistance, elevated proinflammatory cytokines, and impaired antioxidant defenses. The threshold VC exposure and the role of other chemical agents in TASH are as yet unknown.

The use of dynamic positron emission tomography imaging for evaluating the carcinogenic progression of intestinal metaplasia to esophageal adenocarcinoma.

BACKGROUND: In this study, we investigate the use of PET scanning in the carcinogenic progression of reflux esophagitis to Barrett's esophagus to high grade dysplasia to esophageal adenocarcinoma, and correlate the uptake levels of 18F-FDG related to histological changes, and the rates of proliferation and apoptosis. METHODS: An established esophagoduodenal anastomsis rat model in conjunction with micro-PET scanning at 1 week, 1 month, 3 month, and 6 month after procedure was performed. RESULTS: Increased uptake levels of 18F-FDG were observed in the esophagi after EDA procedure. The higher level of 18F-FDG uptake within esophageal epithelium was identified in intestinal metaplastic transformation and esophagoduodenal adenocarcinoma by histological examination. CONCLUSIONS: Dynamic PET scanning represents a powerful tool in analyzing morphological carcinogenic transformation non-invasively in the esophagus. 18F- FDG accumulation was a sensitive marker in reflux esophageal injury carcinogenic progression from intestinal metaplasia to EAC.

Chemoprevention of carcinogenic progression to esophageal adenocarcinoma by the manganese superoxide dismutase supplementation.

PURPOSE: Oxidative stress is related to the carcinogenic pathway of reflux esophagitis to Barrett's metaplasia to esophageal adenocarcinoma (EAC). Recent studies have shown that a decreased manganese superoxide dismutase (MnSOD) level is associated with the increased incidences of Barrett's esophagus (BE) and EAC. The aim of this study was to investigate MnSOD supplementation as a chemopreventive agent to prevent oxidative injury and subsequent BE and EAC formation. EXPERIMENTAL DESIGN: Our esophagoduodenal anastomotic (EDA) model was done on rats according to our established procedure and treated with Mn(III)tetrakis(4-benzoic acid) porphyrin (MnTBAP; 10 mg/kg, i.p. every 3 days). Histologic changes were determined after the EDA model at 1, 3, and 6 months. Lipid peroxidation and 8-hydroxy-deoxyguanosine for DNA oxidative damage were determined by thiobarbituric acid-reactive substance assay and immunohistochemical staining. Enzymatic activities of MnSOD and Cu/ZnSOD were evaluated, and the rate of proliferation was determined by proliferating cell nuclear antigen staining. RESULTS: Severe esophagitis was seen in 100% of the EDA rats, and morphologic transformation within the esophageal epithelium was observed with intestinal metaplasia (40% of animals) and cancer (40% of animals) identified after 3 months. Decreased oxidative damage, along with the decreased degree of esophagitis and incidence of BE (20%) and EAC (0%), was found in MnTBAP-treated EDA rats comparing with the saline-treated EDA control. Decreased proliferation (46%) and increased SOD enzymatic activities (25%) were also found in the EDA rats treated with MnTBAP. CONCLUSION: MnTBAP protected rat esophageal epithelium from oxidative injury induced by EDA, and it could prevent the transformation of esophageal epithelial cell to BE to EAC by preservation of antioxidants.

Loss of manganese superoxide dismutase expression and activity in rat esophagus with external esophageal perfusion.

BACKGROUND: Manganese superoxide dismutase (MnSOD), the primary antioxidant enzyme that scavenges superoxide radicals found in the mitochondria, has been shown to protect oxygen-utilizing cells from the toxicity of the reactive oxygen species (ROS). Current studies in the animal esophageal reflux model are limited, and the reports on the relevance of protein expression level and enzymatic antioxidative activity of MnSOD in esophageal mucosal defense are controversial. Thus, the aim of this study is to investigate the role of MnSOD expression and activity in rats with esophageal perfusion injury. METHODS: We have established a novel external esophageal perfusion (EEP) animal model that allows for esophageal reflux injury. We used the model with 0.5% bovine bile as the perfusion agent in one group of rats and used saline in another group to serve as controls. The esophageal mucosal was isolated for MnSOD expression and activity analysis. RESULTS: Severe esophagitis was observed in the mucosa at 1, 2, and 4 week(s) after bile perfusion. A significant decrease in MnSOD expression with bile perfusion was demonstrated by Western blotting and immunohistochemical evaluation. Similarly, a reduction in MnSOD enzyme activity was observed in bile-perfused rats compared with the saline-perfused controls; no decrease in copper/zinc SOD enzyme activity was observed. CONCLUSIONS: MnSOD expression and activity is decreased in bile-induced esophagitis. This decrease in MnSOD expression and activity is associated with esophagitis and cell death. This study suggests that the loss of MnSOD protein contributes to the reduced level of its enzymatic activity and plays a key role in the induction of esophagitis.

Morphological transformation in esophageal submucosa by bone marrow cells: esophageal implantation under external esophageal perfusion.

Accumulating clinical and experimental studies indicate that Barrett's esophagus might arise through multipotential stem cells under the stress of gastroesophageal reflux. Previously, we have presented a novel external pump perfusion rat model and demonstrated that perfusion with both acid and bile can induce severe esophagitis in 1 week with a similarly pathological change seen in humans. The aim of this study was to investigate the histological changes of esophagus after bone marrow cell engraftment with bile and acid perfusion. The external pump perfusion procedure involved implantation of a microosmotic pump for esophageal perfusion. Bone marrow cells were obtained by flushing of the femur marrow, and the cell suspension was injected between the esophageal muscular and inner mucosa layer. Histological changes were determined after 4 weeks of perfusion. Proliferating cell nuclear antigen, 8-hydroxy-deoxyguanosine, manganese superoxide dismutase, and apoptosis were measured by immunohistochemical staining and TUNEL assay, respectively. Severe esophagitis was seen in both acid and bile perfusion. Bone marrow engraftment and potentiation was seen in both the acid and bile perfusion, when compared to saline controls. Glandular-like cells in submucosa, consistent with intestinal metaplasia, confirmed by Alcin Blue-PAS staining were observed after bone marrow esophageal implantation along with bile perfusion, but not with acid perfusion and controls. Bone marrow implantation in conjunction with esophageal reflux injury contributes to abnormal histological changes consistent with early Barrett's esophageal changes. Engrafted bone marrow cells proliferate under oxidative stress conditions with bile perfusion.

Cyclooxygenase-2 and epithelial growth factor receptor up-regulation during progression of Barrett's esophagus to adenocarcinoma.

AIM: To investigate the expression of cyclooxygenase-2 (COX-2) and epithelial growth factor receptor (EGFR) throughout the progression of Barretts esophagus (BE). METHODS: COX-2 and EGFR protein expressions were detected by using immunohistochemical method. A detailed cytomorphological changes were determined. Areas of COX-2 and EGFR expression were quantified by using computer Imaging System. RESULTS: The expressions of both COX-2 and EGFR increased along with the progression from BE to esophagus adenocarcinoma (EAC). A positive correlation was found between COX-2 expression and EGFR expression. CONCLUSION: COX-2 and EGFR may be cooperative in the stepwise progression from BE to EAC, thereby leading to carcinogenesis.

Rosai-Dorfman disease of the gastrointestinal tract: report of a case and review of the literature.

Rosai-Dorfman disease (RDD) is a rare, acquired disease of unknown etiology that affects primarily children and young adults. It is characterized by a proliferation of distinctive histiocytes in the lymph nodes and/or extranodal sites. Involvement of the gastrointestinal tract is rare. We report a case of RDD in a 60-year-old woman who presented with hematochezia and was found to have RDD of the rectum presenting as a rectal mass. This report highlights the current pathogenetic mechanisms, immunohistochemical markers, and the gastrointestinal manifestations of RDD.

Flt3-ligand treatment prevents diabetes in NOD mice.

The mechanism by which mixed chimerism reverses autoimmunity in type 1 diabetes has not been defined. NOD mice have a well-characterized defect in the production of myeloid progenitors that is believed to contribute significantly to the autoimmune process. We therefore investigated whether chimerism induces a correction of this defect. Mixed chimerism restored production of myeloid progenitors in NOD mice to normal levels. Notably, NOD bone marrow cells as well as donor bone marrow cells produced the mature myeloid progeny, and the level of donor chimerism was not correlated with the degree of restoration of the defect. Moreover, NOD bone marrow cells cultured with Flt3-ligand developed a heat-stable antigen-positive/Ly6C+ population comprised primarily of mature myeloid dendritic cells, suggesting that the underlying abnormality is not cell intrinsic but rather due to a block in development of mature myeloid progeny, including myeloid dendritic cells. Strikingly, treatment of NOD mice with Flt3-ligand significantly decreased insulitis and progression to diabetes and was associated with a significant increase in myeloid dendritic cells and in vivo induction of CD4+/CD25+ cells in the pancreatic lymph node. Therefore, Flt3-ligand treatment and/or the establishment of mixed chimerism in prediabetic candidates may provide a benign and novel approach to treat diabetes.

Association of manganese superoxide dismutase expression with progression of carcinogenesis in Barrett esophagus.

HYPOTHESIS: The down-regulation of manganese superoxide dismutase (MnSOD) expression plays a role in the progression of Barrett esophagus (BE). DESIGN: An evaluation of 92 esophageal samples, including 17 patients with normal esophagus, 22 with intestinal metaplasia, 22 with indefinite/low-grade dysplasia, 16 with high-grade dysplasia (HGD), and 15 with esophageal adenocarcinoma were evaluated for MnSOD expression. We evaluated MnSOD expression using immunohistochemistry and graded it separately on a 2-category ordinal scale in relation to the mucosa and submucosa that ranged from 0 (no staining) to 3 (strong staining). The total grading score of MnSOD immunoreactivity was the addition of mucosa and submucosa intensity, from 0 (no immunoreactivity in any of the anatomic sites) to a maximum score of 6 (strong staining reaction in both of the histoanatomic sites). SETTING: Study subjects were recruited from the Barrett's Esophageal Registry at the University of Louisville, Louisville, KY. MAIN OUTCOME MEASURE: Manganese superoxide dismutase expression in established groups of progressive BE. RESULTS: Ninety-two samples were evaluated for MnSOD expression. The expression of MnSOD was found to be significantly reduced in samples with specialized intestinal metaplasia (mean score, 1.8), low-grade dysplasia (mean, 2.2), high-grade dysplasia (mean, 2.4), and esophageal adenocarcinoma (mean, 2.4) when compared with normal esophagus (mean, 3.9; P = .002). Manganese superoxide dismutase expression was similar for esophageal adenocarcinoma and high-grade dysplasia. CONCLUSIONS: Manganese superoxide dismutase expression is significantly reduced in patients with BE with high-grade dysplasia and esophageal adenocarcinoma. Manganese superoxide dismutase is related to the progression of BE and may represent one of the primary factors in oxidative stress protection. Further evaluation within genotypic expression and the role of antioxidants is needed in the effective screening and treatment of BE.

Helicobacter infections with rare bacteria or minimal gastritis: Expecting the unexpected.

BACKGROUND: The routine use of special stains for detection of Helicobacter remains controversial. AIMS: To determine the frequency of histologically atypical Helicobacter infection. METHODS: All gastric biopsies received at a large pathology reference laboratory over a 6-month period were stained for Helicobacter, and the histologic and clinicopathologic parameters evaluated. RESULTS: Amongst 7663 Helicobacter-positive biopsies, 823 (10.7%) did not show typical chronic active gastritis with numerous Helicobacter organisms, and were therefore considered histologically atypical. Rare Helicobacter pylori organisms accounted for 58.0% of all atypical infections; the next most common atypical Helicobacter infection was that with minimal or no gastric inflammation (23.3% of atypical infections). Patients in these groups did not differ demographically from those with other forms of atypical or typical Helicobacter infection, although a small subgroup (6%) was more likely to have had a previously treated infection. CONCLUSIONS: In many of these atypical infections, Helicobacter would not have been suspected based on the histologic findings alone, and would have been missed without routine special stains. Performing a sensitive stain could prevent additional testing and allow prompt treatment of the affected patients, thus substantially reducing the risk for peptic ulcer and gastric cancer and preventing the transmission of the infection to family members.

Targeting of glycosaminoglycan-cytokine interactions as a novel therapeutic approach in allotransplantation.

BACKGROUND: Glycosaminoglycans (GAGs) are heteropolysaccharides present as integral components of the extracellular matrix (ECM), cell and basement membranes. GAGs play an important role in immune and inflammatory responses because of their ability to interact with cytokines and chemokines, promoting the localization of these molecules onto the ECM or cell membranes at specific anatomical sites. The main goal of these studies was to test the hypothesis that interference with the binding of cytokines/chemokines to GAGs will interfere with a graft rejection response. METHODS: MC-2, a cationic peptide derived from the sequence of the heparin-binding domain of mouse interferon gamma, was used as an inhibitor of the binding of cytokines/chemokines to GAGs. The effects of this peptide were studied in an allogeneic transplantation model involving vascularized rat skin flaps. RESULTS: The MC-2 peptide was found to inhibit binding of interferon-gamma, as well as that of the chemokines, interleukin-8, interferon gamma inducible protein-10, and regulated on activation normal T cell expressed and secreted (RANTES), to GAGs in vitro. Direct administration of MC-2 in an allogeneic skin flap transplantation model resulted in a significantly delayed time of rejection, from 5.4 +/- 0.5 days (control; n=6) to 12.6 +/- 1.6 days (treated animals; n=10). Histopathologic analysis of the skin biopsies was consistent with the delayed rejection process in those animals receiving the peptide, showing only mild signs of rejection up to day 11 (in contrast, all control animals had rejected their flaps by day 6). CONCLUSIONS: These results are consistent with the idea that GAG-cytokine interactions constitute valid therapeutic targets and suggest the potential applicability of such an approach in the prevention of graft rejection.

Association of metallothionein expression and lack of apoptosis with progression of carcinogenesis in Barrett's esophagus.

Barrett's esophagus is the transformation of normal esophageal squamous epithelium to specialized intestinal metaplasia (SIM). Among the Barrett's specialized cells, those that can develop protective mechanisms against apoptosis may have potential to become malignant. Studies have shown that overexpression of metallothionein (MT), low molecular protein that protects cells from apoptotic stimuli, appears to be associated with more advanced, highly malignant tumors. We thus investigated the relationship between MT expression and apoptosis in different stages of Barrett's carcinogenesis. Terminal deoxyribonucleotidyl transferase-mediated dUTP-digoxigenin nick end labeling and immunohistochemical dual-staining assay were performed in human biopsy samples of normal, SIM, dysplasia, and adenocarcinoma. Apoptotic index and MT expression were quantified by using an image system to analyze the converted digital data. A negative correlation between MT expression and apoptotic index was found. MT expression was significantly increased along with the histologic progression towards adenocarcinoma. This study thus suggests that MT may contribute to cytoprotection, thereby inhibiting apoptosis and leading to carcinogenesis of Barrett's esophageal cells.

Significant increase in IgG4+ plasma cells in gastric biopsy specimens from patients with pernicious anaemia.

AIM: To investigate the presence of IgG4+ plasma cells in gastric mucosal biopsy samples from patients with atrophic gastritis (AG) and a history of pernicious anaemia (PA) (AG+PA+). METHODS: Gastric mucosal biopsy specimens from 46 patients with AG+PA+ were investigated. As controls, we evaluated specimens from patients with AG but no history of PA (AG+ PA-) (n=25), normal histology (n=25), mild chronic inactive gastritis (MCIG) (n=25) or Helicobacter pylori gastritis (HP) (n=25). IgG4+ plasma cells were detected by two immunohistochemical methods: (1) using a monoclonal antibody, the average of the three most cellular high-power fields was counted in areas with the highest density of IgG4+ plasma cells; (2) using a dual-chromagen stain for both IgG4 and CD138 (plasma cell marker), the number of IgG4+ cells per 200 CD138+ plasma cells was counted. The latter was used to ensure that the number of IgG4+ cells was not simply related to the degree of inflammation (density of plasma cells). RESULTS: Identical results were obtained with the two staining methods. Increased numbers of IgG4+ plasma cells were present in 37% of patients with AG+PA+, but in none with AG+PA-, MCIG, HP or normal gastric biopsy results (100% specific, p=0.0001). CONCLUSION: IgG4+ plasma cells may play a role in the pathogenesis of PA and may be a useful marker for its diagnosis.

Alterations in manganese superoxide dismutase expression in the progression from reflux esophagitis to esophageal adenocarcinoma.

BACKGROUND: Comprehensive understanding of the basic mechanisms in the progression of esophagitis, Barrett esophagus (BE), and esophageal adenocarcinoma (EAC) is urgently needed to develop a management strategy for an effective screening of BE and management of EAC. The aim of this study is to provide a detailed insight of the histology and the cellular and molecular events associated with the genesis of BE and EAC under the esophagoduodenal reflux conditions. METHODS: Esophagoduodenal anastomosis (EDA) was performed on rats. Animals were weighed weekly and killed after 1, 2, 3, 4, 5, and 6 months. The entire esophagi were examined for macroscopic and microscopic changes and for manganese superoxide dismutase (MnSOD) expression, and TUNEL (terminal deoxynucleotidyl transferase dUTP nick-end labeling) assay was performed. RESULTS: Morphological transformation from esophagitis (100% of animals) to BE (66% of animals) to EAC was observed after 3 months. There was marked loss of MnSOD expression in animals with esophagitis and BE at 1 and 2 months, with an increase in expression during the transformation to dysplasia and EAC. Increased proliferation and apoptosis was observed and reached a peak at months 1 and 2. Greatly increased levels of 8-hydroxy-deoxyguanosine was found during the progression to EAC. CONCLUSIONS: The morphological transformation of the esophageal mucosa is an adaptive process, and it is an important foundation for the transdifferentiation of BE and cancer. The significant loss of MnSOD expression to achieve BE and then the adaptive increase in expression to achieve dysplasia and EAC during this transformation may represent a predictive marker in identifying patients who will progress from BE to EAC.

A novel external esophageal perfusion model for reflux esophageal injury.

The current animal models of esophagitis and Barrett's esophagus consist of surgeries that divert the gastroduodenal contents to the esophagus. The limitations of these models are the inability to control the amount and concentration of the refluxate and the causing of significant postoperative stress and morbidity. Eighteen adult rats were cannulated at the upper esophagus and connected to a subcutaneous osmotic micropump to perfuse the esophageal lumen with bile and acid. Animals were sacrificed after 7 days of perfusion. Histological changes were determined. Cell proliferation, apoptosis, lipid peroxidation, and glutathione were measured. Histopathological changes in the bile- or acid-perfused esophagus were consistent with the findings associated with reflux esophagitis. Enhanced proliferation and apoptosis were seen, along with increased oxidative stress. The external esophageal perfusion model enabled precise control of the injurious agent. It induced the histologic and cellular injury of reflux esophagitis after 7 days.

Slow transit colon constipation is not related to the number of interstitial cells of Cajal.

BACKGROUND AND AIMS: Recent studies have demonstrated decreased numbers of interstitial cells of Cajal in patients suffering from severe chronic constipation as measured by c-Kit (CD117) and CD34 immunohistology. In this study, we wished to determine whether there were abnormalities in the number of neurons of the Auerbach's plexus, their CD117 and CD34 immunoreactivity, or the thickness of colon wall sections in patients with refractory slow transit colonic constipation as compared with control subjects. PATIENTS AND METHODS: Specimens from 13 patients who had undergone subtotal colectomy for severe chronic constipation refractory to medical treatment were compared with normal controls. Enteric neurons of Auerbach's plexus were counted, and thickness of the circular and longitudinal layer of the muscularis externa as well as total muscularis externa was measured. Quantitative assessment of anti-CD117 and anti-CD34 immunoreactivity was performed using an Automated Cellular Imaging System and expressed as fractional scores. RESULTS: Except for a decreased circular muscle layer thickness in the constipated patients, no statistically significant differences were observed between the two groups. In particular, there was no relationship between CD117/CD34 fractional staining score and the duration or severity of disease, despite the selection of highly symptomatic individuals requiring colonic resection. CONCLUSION: Using quantitative immunohistochemistry for CD117/CD34, we could not detect a relationship between fractional CD117/CD34 staining score and chronic constipation as compared to controls.

Preconditioning of NOD mice with anti-CD8 mAb and costimulatory blockade enhances chimerism and tolerance and prevents diabetes, while depletion of alpha beta-TCR+ and CD4+ cells negates the effect.

Bone marrow transplantation blocks diabetes pathogenesis and reverses autoimmunity in nonobese diabetic (NOD) mice. However, there is a greater barrier to engraftment in the context of autoimmunity. In the present study, we characterized which recipient cells influence engraftment in prediabetic NOD mice, with the goal to replace myelotoxic conditioning with antigen-specific deletion of reactive host cells. Preconditioning of NOD mice with anti-CD8 and anti-CD154 monoclonal antibodies (mAbs) synergistically enhanced engraftment and significantly reduced the minimum total body irradiation (TBI) dose for engraftment. Strikingly, preconditioning with anti-CD4 mAb significantly impaired engraftment, negating the beneficial effect of anti-CD8, and resulted in a requirement for more TBI-based conditioning compared with controls conditioned with TBI alone. Similarly, more TBI was required when anti-T-cell receptor beta (TCRbeta) mAb was administered as preconditioning. The addition of anti-CD152 to CD154 preconditioning abrogated the engraftment-enhancing effect of anti-CD154. Taken together, these data indicate a role for CD4+ regulatory T cells in vivo which require signaling via CD152 in the induction of chimerism and tolerance in NOD recipients. Notably, disease prevention and reversal of autoimmunity was absolutely correlated with the establishment of chimerism. These studies have important implications for the design of novel clinical approaches to treat type 1 diabetes.

Esophageal injury with external esophageal perfusion.

BACKGROUND: External esophageal perfusion (EEP) with the idea that esophageal perfusion can be controlled with a single ingredient at a constant rate and concentration, might be used to dissect the injurious role of gastro-duodenal secretions for the progression from esophagitis to Barrett's esophagus (BE) and esophageal adenocarcinoma (EAC). This study is to evaluate the EEP rat model for esophagitis induced by using a micro-osmotic pump with bile perfusion. METHODS: Eighteen adult rats underwent the EEP procedure. Bile (0.5% bovine bile, pH 7.4) was used as perfusion agent and three types of perfusions were performed: 1 week perfusion, 2 weeks perfusion, and 4 weeks perfusion compared to saline perfusion and sham operation. Histological changes, cell proliferation, apoptosis, 8-hydroxy-deoxyguanosine (8-OH-dG) and Manganese superoxide dismutase (MnSOD) were observed after perfusion and compared. RESULTS: The bile perfusion for 1 week, 2 weeks, and 4 weeks induced mucosa infiltration of inflammatory cells, basal cell hyperproliferation, and papillae hypertrophy in all animals. Histopathology and cellular changes consistent with the findings associated with reflux esophagitis. The apoptotic index, the proliferating index, and expression of 8-OH-dG were significantly increased in the esophageal mucosa compared to controls. MnSOD expression was decreased with bile perfusion compared to saline controls. CONCLUSIONS: The external esophageal perfusion model enabled precise control of the injurious agent. It induced the typical histological injury and cellular changes seen in severe reflux esophagitis. The cellular changes in apoptosis, proliferation and anti-oxidant defense make this model unique for reflux esophagitis studies. Further studies are needed to induce Barrett's esophagus and esophageal adenocarcinoma.

Efficacy of a transforming growth factor beta 2 containing nutritional support formula in a murine model of inflammatory bowel disease.

OBJECTIVE: Dietary, environmental and genetic events may influence host susceptibility to inflammatory bowel diseases (IBD). Transforming growth factor beta 2 (TGF-beta 2), a multifunctional polypeptide (cytokine) present in human and bovine milk, plays a critical role in the development of tolerance, the prevention of autoimmunity, and in anti-inflammatory responses. TGF-beta 2 is a potent inhibitor of intestinal epithelial cell (IEC) growth and stimulates IEC differentiation. The objective of this study was to determine whether a diet containing TGF-beta 2 modulates intestinal injury and immune responses in an Interleukin-10 knockout (IL-10-/-) mouse model of IBD. METHODS: Five-week-old IL-10-/- mice (in BALB/c background) reared in our transgenic facility were fed either an enteral diet (Diet-A) containing TGF-beta 2 or a control enteral diet (Diet-B) not rich in TGF-beta 2. Mice were weighed weekly, monitored for illness and euthanized after eight weeks on the diet. RESULTS: Final weights were 28 +/- 1.2 g (58.2% gain) for Diet-A mice and 23 +/- 1.6 g (32.9% gain) for Diet-B mice (p = 0.0194). The hematocrits were 48.3% for Diet-A compared to 42% for Diet-B mice (p = 0.0021). Mice on Diet-A had significantly lower serum TNF-alpha concentrations. Forty-four percent of mice on Diet-B developed severe diarrhea and rectal prolapse compared with none on Diet-A. Evaluation of intestinal pathology (score 0-4) revealed that animals fed Diet-A had a score of 2.1 +/- 0.4 compared to 3.2 +/- 0.36 in the Diet-B group (p = 0.040). The acute phase protein, serum amyloid A (SAA), was 3.8 times higher in the Diet-B group (p = 0.0038). CONCLUSIONS: IL-10-/- mice fed a TGF-beta 2 containing diet gained more weight, did not develop diarrhea or prolapse, had lower pathological scores, and lower SAAs. These data further support the use of TGF-beta 2 containing enteral diets as one mode of therapy for Crohn's disease.

p-Aminophenol-induced hepatotoxicity in hamsters: role of glutathione.

p-Aminophenol (PAP) is a widely used industrial chemical and a known nephrotoxin. Recently, it was found to also cause hepatotoxicity and glutathione (GSH) depletion in mice. The exact mechanism of liver toxicity is not known. The aims of this study were to determine whether PAP can cause acute hepatotoxicity in hamsters and to further investigate the role of GSH in PAP-induced toxicity. PAP was administered ip to hamsters in doses of 200-800 mg/kg. Liver damage at 24 h after PAP administration was assessed by elevations in plasma enzyme activities and histopathologic examination. GSH and cysteine (Cys) levels in liver at 4 h were determined by HPLC. PAP decreased hepatic GSH concentration to 8% and Cys to 30% of vehicle control values. It increased plasma glutamic pyruvic transaminase (GPT) activity by 47-fold and sorbitol dehydrogenase (SDH) activity by 113-fold. PAP also caused severe centrilobular hepatocellular necrosis. 2(RS)-n-Propylthiazolidine-4(R)-carboxylic acid (PTCA), a Cys precursor, attenuated the PAP-induced decreases in hepatic sulfhydryl levels; GSH and Cys were 39% and 78% of vehicle controls, respectively. PTCA also attenuated the PAP-induced elevations in plasma enzyme activities and hepatic necrosis. It was concluded that PAP hepatotoxicity is associated with depletion of hepatic GSH and can be prevented by PTCA.