Gene deletion of long-chain acyl-CoA synthetase 4 attenuates xenobiotic chemical-induced lung injury via the suppression of lipid peroxidation

Long-chain acyl-CoA synthetase (ACSL) 4 converts polyunsaturated fatty acids (PUFAs) into their acyl-CoAs and plays an important role in maintaining PUFA-containing membrane phospholipids. Here we demonstrated decreases in various kinds of PUFA-containing phospholipid species in ACSL4-deficient murine lung. We then examined the effects of ACSL4 gene deletion on lung injury by treating mice with two pulmonary toxic chemicals: paraquat (PQ) and methotrexate (MTX). The results showed that ACSL4 deficiency attenuated PQ-induced acute lung lesion and decreased mortality. PQ-induced lung inflammation and neutrophil migration were also suppressed in ACSL4-deficient mice. PQ administration increased the levels of phospholipid hydroperoxides in the lung, but ACSL4 gene deletion suppressed their increment. We further found that ACSL4 deficiency attenuated MTX-induced pulmonary fibrosis. These results suggested that ACSL4 gene deletion might confer protection against pulmonary toxic chemical-induced lung injury by reducing PUFA-containing membrane phospholipids, leading to the suppression of lipid peroxidation. Inhibition of ACSL4 may be promising for the prevention and treatment of chemical-induced lung injury.

Regulation of eotaxin-3/CC chemokine ligand 26 expression by T helper type 2 cytokines in human colonic myofibroblasts

Eotaxins induce the trafficking of eosinophils to the sites of inflammation via CC chemokine receptor 3 (CCR3). In this study, we investigated eotaxin-3/CC chemokine ligand 26 (CCL26) expression in the inflamed mucosa of patients with inflammatory bowel disease (IBD), and characterized the molecular mechanisms responsible for eotaxin-3 expression in human colonic myofibroblasts. Eotaxin-3 mRNA and protein expression was evaluated by real time-polymerase chain reaction (PCR) and enzyme-linked immunosorbent assay (ELISA), respectively. Eotaxin-3 mRNA expression was elevated significantly in the active lesions of ulcerative colitis (UC) patients. Significant elevations were also observed in the active lesions of Crohn's disease (CD) patients, but this was significantly lower than that detected in the active UC lesions. There were no significant increases in the inactive lesions of UC or CD patients. Colonic myofibroblasts were identified as a major source of eotaxin-3 in the colonic mucosa, and interleukin (IL)-4 and IL-13 enhanced eotaxin-3 mRNA and protein expression significantly in these cells. There was a significant positive correlation between mucosal eotaxin-3 and IL-4 mRNA expression in the active lesions of IBD patients. The IL-4- and IL-13-induced eotaxin-3 mRNA expression was regulated by the signal transducer and activator of transcription-6 (STAT-6) and suppressor of cytokine signalling (SOCS)1-mediated pathways. Interferon (IFN)-γ acts as a negative regulator on the IL-4- and IL-13-induced eotaxin-3 expression via STAT-1 activation. Eotaxin-3 expression was elevated specifically in the active lesions of IBD, in particular UC. Eotaxin-3 derived from colonic myofibroblasts may play an important role in the pathophysiology of UC.

Epithelial expression of interleukin-37b in inflammatory bowel disease

Interleukin (IL)-37 is a member of the IL-1 cytokine family. We investigated IL-37b expression in the inflamed mucosa of inflammatory bowel disease (IBD) patients. Furthermore, we analysed IL-37b expression in human colonic epithelial cells. The human colonic epithelial cell line T84 and human colonic subepithelial myofibroblasts (SEMFs) were used. IL-37b expression in the IBD mucosa was evaluated by immunohistochemistry. IL-37b mRNA and protein expression were determined by real time-polymerase chain reaction (PCR) and Western blotting, respectively. IL-37b was not detected in the normal colonic mucosa. In the inflamed mucosa of IBD patients, epithelial IL-37b expression was increased markedly. In ulcerative colitis (UC) and Crohn's disease (CD) patients, IL-37b expression was enhanced in the affected mucosa. In the intestinal epithelial cell line T84, the expression of IL-37b mRNA and protein was enhanced by tumour necrosis factor (TNF)-α. This IL-37b induction by TNF-α was mediated by nuclear factor (NF)-κB and activator protein (AP)-1 activation. Furthermore, IL-37b inhibited TNF-α-induced interferon-γ-inducible protein (IP)-10 expression significantly in human colonic SEMFs. Epithelial IL-37b expression was increased in IBD patients, especially UC patients. IL-37b may be involved in the pathophysiology of IBD as an anti-inflammatory cytokine and an inhibitor of both innate and acquired immune responses.

CD44 variant 9 expression in primary early gastric cancer as a predictive marker for recurrence

BACKGROUND

Multiple early gastric cancers (EGCs) may develop in 6-14% of patients even after achieving curative endoscopic submucosal dissection (ESD); however, a useful biomarker for predicting recurrence is not available. The present study investigated whether the expression of CD44 variant 9 (CD44v9), a functional cancer stem cell marker, in the primary gastric cancer tissue represents an indicator of recurrence.

METHODS

Eighty-eight patients who underwent ESD for EGC from 2008 to 2010 were enrolled and monitored for recurrence for 3 years. The expression levels of CD44v9 in the tissue of initial EGCs were evaluated by immunohistochemistry, and the recurrence rate was compared between CD44v9-positive and CD44v9-negative groups. The mucin phenotype and expression of microRNA-21 (miR-21) and programmed cell death protein 4 (PDCD4) were also analysed.

RESULTS

The recurrence rate of EGC was significantly higher in the CD44v9-positive group than in the CD44v9-negative group (hazard ratio (HR), 21.8; 95% confidence interval (CI), 5.71-83.1). However, mucin phenotypes and the expression of miR-21 and PDCD4 did not predict recurrence after ESD. Meanwhile, grade of gastric atrophy was also identified as a significant marker of multiple recurrence (HR, 4.95; 95% CI, 1.30-18.8).

CONCLUSION

CD44 variant 9 expression represents a potential predictive marker for recurrence in EGC.

Faecal chitinase 3-like-1: a novel biomarker of disease activity in paediatric inflammatory bowel disease

BACKGROUND

Chitinase 3-like-1 (CHI3L1) is up-regulated in the inflamed mucosa of inflammatory bowel disease (IBD).

AIM

To evaluate the usefulness of a faecal CHI3L1 assay, as a reliable marker for predicting the severity of paediatric IBD.

METHODS

Faecal samples were obtained from ulcerative colitis (UC, n = 94), Crohn's disease (CD, n = 87), and healthy individuals (n = 56). The faecal CHI3L1 and calprotectin levels were determined by ELISA. For endoscopic evaluation, the sum of the Matts' score for UC and the simple endoscopic score for CD (SES-CD) were used. Ileal lesions were evaluated by ultrasonography.

RESULTS

Faecal CHI3L1 levels were significantly elevated in active UC (median 366.6 ng/g, n = 44) and active CD (median 632.7 ng/g, n = 48) patients, as compared with healthy individuals (median 2.2 ng/g, n = 56). In UC patients, the faecal CHI3L1 levels were positively correlated with the sum of the Matts' score (r = 0.73, P < 0.01, n = 42). In CD patients, there was a significant correlation between faecal CHI3L1 levels and endoscopic activity as determined by the SES-CD scoring system (r = 0.61, P < 0.01, n = 25). The faecal CHI3L1 levels of patients with wall thickening of their small intestine were significantly higher than those of healthy controls or patients without wall thickening. The cutoff value of 13.7 ng/g for fecal CHI3L1(the 95th percentile of the control value) predicted active lesions in IBD patients with a sensitivity of 84.7% and a specificity of 88.9%.

CONCLUSION

Faecal CHI3L1 assays may be useful for predicting the severity and activity of mucosal inflammation in IBD.

The increased mucosal mRNA expressions of complement C3 and interleukin-17 in inflammatory bowel disease

Recent studies have demonstrated that the complement system participates in the regulation of T cell functions. To address the local biosynthesis of complement components in inflammatory bowel disease (IBD) mucosa, we investigated C3 and interleukin (IL)-17 mRNA expression in mucosal samples obtained from patients with IBD. The molecular mechanisms underlying C3 induction were investigated in human colonic subepithelial myofibroblasts (SEMFs). IL-17 and C3 mRNA expressions in the IBD mucosa were evaluated by real-time polymerase chain reaction. The C3 levels in the supernatant were determined by enzyme-linked immunosorbent assay. IL-17 and C3 mRNA expressions were elevated significantly in the active lesions from ulcerative colitis (UC) and Crohn's disease (CD) patients. There was a significant positive correlation between IL-17 and C3 mRNA expression in the IBD mucosa. IL-17 stimulated a dose- and time-dependent increase in C3 mRNA expression and C3 secretion in colonic SEMFs. The C3 molecules secreted by colonic SEMFs were a 115-kDa alpha-chain linked to a 70-kDa beta-chain by disulphide bonds, which was identical to serum C3. The IL-17-induced C3 mRNA expression was blocked by p42/44 mitogen-activated protein kinase (MAPK) inhibitors (PD98059 and U0216) and a p38 MAPK inhibitor (SB203580). Furthermore, IL-17-induced C3 mRNA expression was inhibited by an adenovirus containing a stable mutant form of I kappaB alpha. C3 and IL-17 mRNA expressions are enhanced, with a strong correlation, in the inflamed mucosa of IBD patients. Part of these clinical findings was considered to be mediated by the colonic SEMF response to IL-17.

Novel single-balloon enteroscopy for diagnosis and treatment of the small intestine: preliminary experiences

BACKGROUND AND AIM

As a tool for examining the small intestine, double-balloon enteroscopy (DBE) has been used routinely. However, there remain a few issues relating to the handling of DBE, such as attaching a balloon to the tip of the scope, and inflating/deflating the two balloon systems. Recently, we developed a novel single-balloon enteroscopy (SBE) system for the examination of the small intestine. The aim of the present study was to evaluate the insertion technique, the safety, and the clinical impact of the SBE system.

PATIENTS AND METHODS

Between January 2006 and June 2007, all patients undergoing enteroscopy with the Olympus SBE system (length 200 cm, outer diameter 9.2 mm) were studied. Instead of a balloon attached to the distal scope end, the distal scope end was hook-shaped, and manipulating the up-angle or down-angle of the scope end enabled exploration of the small intestine.

RESULTS

A total of 78 procedures were performed in 41 patients (24 men, 17 women; mean age 48.9 years, range 23 - 85 years). The indications for the examination were suspected mid-gastrointestinal bleeding (n = 12), Crohn's disease (n = 17), abdominal pain (n = 8), and abdominal tumor (n = 4). The mean procedure time was 62.8 +/- 20.2 minutes and 70.4 +/- 19.3 minutes for the oral and anal routes, respectively. Among 24 patients in whom total enteroscopy was attempted, the entire small intestine was explored in 6.

CONCLUSION

SBE is not only easy to perform, due to the single balloon, but it can also safely examine the deep small intestine. Therefore, SBE may be a useful diagnostic and therapeutic tool in addition to DBE for investigating suspected small bowel disease.

A new technique for endoscopic submucosal dissection for early gastric cancer using an external grasping forceps

BACKGROUND AND STUDY AIMS

Endoscopic submucosal dissection (ESD) for early gastric cancer (EGC) has improved the success rate of en-bloc resection. We report here on a new technique using an external grasping forceps.

PATIENTS AND METHODS

A total of 25 patients with suitable EGCs over 10 mm in diameter located in the gastric body were enrolled. After submucosal injection followed by circumcision of the lesion with a needle-knife, an external grasping forceps was introduced with the help of a second grasping forceps and anchored at the distal margin of the lesion. With gentle oral traction applied with this forceps, the lesion was dissected endoscopically in retroversion from the aboral side.

RESULTS

The mean lesion size was 15.0 mm (range 10 - 25 mm). Using the technique described, all lesions could be resected en bloc with free margins. The mean procedure time was 45 min (range 30 - 80 minutes). No significant bleeding requiring blood transfusion or perforation occurred.

CONCLUSIONS

This technical modification may simplify and shorten the gastric ESD procedure, except for lesions in distal locations, without compromising the efficacy.

A novel treatment for refractory primary biliary cirrhosis?

BACKGROUND/AIMS

Bezafibrate is naturally used for hyperlipidemia worldwide. In 1992 Day et al reported that the value of ALP and gamma-GTP in hyperlipidemia declined after administering bezafibrate orally. We conducted a study to investigate whether or not ALP and gamma-GTP in primary biliary cirrhosis which is characterized by the elevation of these enzymes improved after taking bezafibrate.

METHODOLOGY

We administered bezafibrate additionally for 6 months to 13 patients with primary biliary cirrhosis (refractory PBC) whose liver enzymes (ALP or gamma-GTP) did not remain within normal range out of 21 patients treated by monotherapy of ursodeoxycholic acid for 18 months.

RESULTS

At 2, 4, and 6 months, gamma-GTP level significantly decreased compared with that prior to the initiation of bezafibrate. At 4 and 6 months, ALP level significantly decreased compared with that prior to the initiation. At 2, 4 and 6 months, ALT level significantly decreased compared with that prior to the initiation. The value of IgG and IgM was also reduced significantly 6 months after the initiation.

CONCLUSIONS

If the effectiveness of bezafibrate for primary biliary cirrhosis is confirmed histologically and by a randomized trial, a combination therapy of bezafibrate and ursodeoxycholic acid appear to be the medical treatment of choice for primary biliary cirrhosis in the future.

Urinary pyrimidine analysis in healthy newborns, infants, children, adults and patients with congenital metabolic diseases

BACKGROUND

In previous reports, the reference range for urinary pyrimidine was determined on the basis of a small number of samples, with data for only a few patients being reported. In the present study, we measured urinary pyrimidine compounds in 25 healthy newborns, 33 healthy infants, 130 healthy children and 166 healthy adults. In addition, we also analyzed urinary pyrimidine compounds in various patients with abnormal pyrimidine metabolism, such as congenital pyrimidine metabolism disorders and urea cycle disorders.

METHODS

We analyzed urines by high-performance liquid chromatography with column switching. Analyses were performed with both a reverse-phase column and an anion-exchange column. The columns were connected by a column switch, with all systems being controlled automatically by a computerized system controller.

RESULTS

The excretion of pyrimidine compounds in patients with abnormal pyrimidine metabolism (containing heterozygotes) was out of our reference ranges.

CONCLUSIONS

These results suggest that urinary pyrimidine analysis is a useful index for the diagnosis of pyrimidine metabolism disorders, urea cycle disorders and these heterozygotes. Based on this large-group analysis of healthy individuals, we were able to determine the reference ranges of urinary orotic acid, dihydrouracil and uracil for each age group.

Analysis of clinical course and long-term prognosis of surgical and nonsurgical patients with intestinal Behçet's disease

OBJECTIVE

Much remains unknown about the pathogenesis of intestinal Behçet's disease. The majority of these patients are treated with surgical intervention, although it has been recently reported that a number of medical treatments are sometimes effective. Only few studies, however, have ever been undertaken to analyze the long-term prognosis of this disease. In this study, we analyzed the clinical course and the recurrences after initial therapy in patients with intestinal Behçet's disease.

METHODS

We investigated 20 patients (surgical group, n = 8; nonsurgical group, n = 12) for whom the clinical courses were known for > or = 2 yr (2-23 yr).

RESULTS

The surgical group tended to have higher rates of complications such as ocular and ileal lesions than the nonsurgical group. In the surgical group, 75% of the patients recurred (and were readmitted) within 2 yr, and 37.5% of the patients required reoperation for intestinal obstruction because of ulcer at the anastomosis. The percentage of peripheral CD8+ DR+ lymphocytes in the recurrent group (10.4% +/- 2.5%) was significantly higher than that in the nonrecurrent group (4.3% +/- 1.2%, p < 0.05).

CONCLUSIONS

Our results indicate that more extensive disease involving the ileum and ocular lesions are markers of severity and progression to surgical crisis, and that patients requiring surgery suffer more frequent recurrences. Furthermore, an increased percentage of peripheral CD8+ DR+ lymphocytes may be a risk factor for disease recurrence.

[Pneumoperitoneum with systemic sclerosis]

We report a case of systemic sclerosis (SSc) complicated with benign pneumoperitoneum without apparent pneumatosis cystoides intestinalis (PCI). A 43-year-old woman was admitted to our hospital because of prominent abdominal distension in April 1997. Raynaud's phenomenon has been detected since 1991. She was suffering from recurrent diarrhea, constipation, and subileus. The diagnosis of SSc was made in 1996 based on the sclerosis in her face, forearms, and chest, and hypomotility of the esophagus. On admission, she presented no signs of peritoneal irritation. The laboratory data revealed that white blood cell count was 7,400/mm3 and C-reactive protein was 0.1 mg/dl. Chest and abdominal roentgenograms showed massive free air under the diaphragm, dilatation of small and large intestine, and air-fluid level. PCI was not apparent. Pneumoperitoneum was improved after four weeks with intravenous hyperalimentation. But she presented recurrent severe diarrhea and high fever whenever she tried to take food orally. Klebsiella pneumoniae was proved in her jejunal juice by bacteriologic examination. Intravenous prostaglandin F2 alpha and oral fosfomycin calcium intake made her condition better. Benign pneumoperitoneum without PCI is rarely reported in the patients with SSc. In her condition, weakness of intestinal wall, hypomotility of intestine, unusual bacterial overgrowth, and elevated intraluminal pressure made intraluminal gas go through the wall of the fragile intestine of SSc. As operation of intestine of SSc usually cause miserable outcome, pneumoperitoneum accompanied with SSc even if PCI is apparent or not must be treated with conventional manner while there is no signs of peritoneal irritation.

Hereditary orotic aciduria heterozygotes accompanied with neurological symptoms

We report a family with hereditary orotic aciduria heterozygotes. A 3-year-old boy who had been diagnosed as having cerebral palsy and mental retardation presented himself with an increase in excretion of urinary orotic acid. Enzymatic studies revealed that the boy and his healthy mother were hereditary orotic aciduria heterozygote carriers. We can not prove that this pyrimidine disorder caused his neurological symptoms, but his pyrimidine nucleoside supply may have been insufficient in his neonatal period.

[An autopsy case of anti-neutrophil cytoplasmic antibodies associated vasculitis accompanied by autoimmune hepatitis and hepatocellular carcinoma]

Here we report an autopsy case with anti-neutrophil antibodies (ANCA) associated vasculitis accompanied by autoimmune hepatitis and hepatocellular carcinoma. A 69-year-old woman was admitted to Tokyo Metropolitan Ohtsuka Hospital in October 1995 because of leg edema. She had presented cough in 1990 and diagnosed as interstitial pneumonia, esophageal varices and liver chirosis. On admission, laboratory data showed mild anemia, hypoproteinemia, and marked gammagloblinemia. IgM-HA antibody, HBs antigen, HBs antibody, HCV antibody and HDV antibody were negative. Anti-nuclear antibody, anticentromere antibody, anti-neutrophil cytoplasmic antibody against myeloperoxidase and cathepsin G (MPO-ANCA and cathepsin G), rheumatoid factor and direct coombs test were positive. Serum level of AFP and CEA were elevated. Ultrasonography and computed tomography of abdomen scowed liver chirosis and tumor in left lobe of liver. The diagnosis of liver chirosis based on autoimmune hepatitis and Interstitial pneumonia was made with clinical course, laboratory findings and radiographic findings although liver biopsy was not performed. She complained of bloody stool due to ulcer of the large intestine, and died of liver failure which progressed rapidly. The autopsy findings detected that pulmonary fibrosis, liver fibrosis with multiple hepatocellular carcinoma, necrotizing crescentic glomerulonephritis, and vasculitis of small artery inn colon. This was the first report of MPO-ANCA associated vasuculitis complicated with autoimmune hepatitis and hepatocellular carcinoma. Clinical significance of ANCA and immunogenetic background of these diseases were discussed.

Reversal of altered intestinal mucosal immunity in rats fed elemental diet by supplementation of oleic acid

We have previously demonstrated that elemental diet (ED) induces decreased lymphocyte transport in intestinal lymph and significant changes in T cell subsets and the number of IgA-containing cells in gut-associated lymphoid tissues of rats. In order to examine whether the low fat content contributes to the induction of immunological changes in gut-associated lymphoid tissues, the effects of additional fatty acid in the ED were investigated. Rats were divided into four groups: elemental diet alone, elemental diet supplemented with 5% oleic acid (OA), elemental diet with 10% OA and conventional diet as a control. These diets were given at the same daily calorie intake for 4 weeks. The flow rate of intestinal lymph showed no significant difference between the four groups. However, lymphocyte flux as well as the percentage of CD3+ and CD4+ cells were significantly greater in the control and the 10% OA groups than in the ED and 5% OA groups. Intestinal lymph showed decreased concentrations of IgG and IgA in the ED group, whereas the addition of 10% OA significantly attenuated the decrease in these levels. In mesenteric lymph nodes, the CD4+/CD8+ ratio was significantly decreased in the ED group, but 10% OA reversed this change. Immunohistochemical analysis of the ileal mucosa showed that in the ED group the population of CD4+ cells was decreased, while the number of CD8+ cells was increased. Supplementation of OA to ED produced similar stepwise attenuation of the changes in lymphocyte subpopulations in the lamina propria, while the 10% OA group reached levels that were not statistically different from controls. In the elemental diet group, there was a significant decrease in immunoglobulin-containing cells of the IgA class in the lamina propria of the intestine. Similarly, the addition of OA induced dose-dependent recovery in the number of IgA-containing cells. These results suggest that a low dietary concentration of fat may be closely related to changes in lymphocyte transport in intestinal lymph and mucosal immunity of intestinal mucosa induced by the feeding of a long-term ED.

Enhanced levels of chemiluminescence and platelet activating factor in urease-positive gastric ulcers

Helicobacter pylori are believed to play an important role in the formation of gastric ulcer in a syndrome characterized by a high urease activity. On the other hand, the production of oxygen radicals and platelet activating factor (PAF) is enhanced in gastric ulcers. The present study is designed to investigate the relationship between the different aspects of gastric mucosal injury, urease activity, oxygen radical production, and PAF content in gastric specimens. Biopsy specimens taken from 35 gastric ulcer patients were studied. Urease activity was detected by a rapid urease test (CLO). Oxygen radical production was measured as a value of luminol-dependent chemiluminescence (ChL) and PAF content was determined by radioimmunoassay in the biopsy samples. The CLO-positive rate was significantly higher in the gastric ulcer group in comparison with that in controls. ChL values and PAF content were significantly increased in gastric ulcers, especially in CLO-positive specimens. The CLO-positive rate, ChL values, and PAF content were also found to be increased at a distant site beyond the ulcer lesions. During the course of macroscopic ulcer healing of CLO-positive cases, the CLO positive level and the ChL values were not significantly decreased, although PAF content was significantly lower. Enhanced oxygen radical and PAF production were observed not only in the ulcer region but also at a distant site from the ulcer in the urease-positive gastric mucosa. The persistent enhancement of ChL values during the healing stage of urease-positive gastric ulcers suggests its involvement in the recurrence of gastric ulcers.

Intravital demonstration of sequential migration process of lymphocyte subpopulations in rat Peyer's patches

BACKGROUND & AIMS

Although recirculation of lymphocytes through Peyer's patches is important for specific immune defense, the intraorgan migration of lymphocyte subpopulations has not been clearly understood. The aim of this study was to compare the spatial distributions of labeled lymphocytes among various subpopulations in rat Peyer's patches.

METHODS

Lymphocytes collected from intestinal lymph were separated into CD4+, CD8+, and T and B cells, labeled with a fluorochrome carboxyfluorescein diacetate succinimidyl ester, and injected into the jugular vein. Peyer's patches of recipient rats were observed by intravital fluorescence microscopy.

RESULTS

No significant difference was found in the percentage of lymphocytes in transit or in the rolling velocity among different subpopulations. Lymphocytes sticking to the venules increased in number at 10-20 minutes, with preferential adherence of CD4+ cells to venules of 25-50 microns and preferential adherence of B cells to the venules of a wider size range. After 30 minutes, extravasated lymphocytes moved into the interstitium. B cells migrated from venules more quickly than CD4+ cells. CD8+ cells showed an intermediate pattern between CD4+ and B cells in sticking and migratory behaviors. Subsequently, CD4+ and CD8 cells preferentially appeared in parafollicular microlymphatics.

CONCLUSIONS

Significant differences were observed among lymphocyte subpopulations in terms of spatial distribution of lymphocytes sticking to venules, migration into the interstitium, and their lymphatic transport.

Conjugated bile salts regulate turnover of rat intestinal brush border membrane hydrolases

The mechanisms whereby the conjugated bile salts regulate the activities of the brush border membrane hydrolases and its physiological significance were investigated in rat small intestine, and comparisons were made with the action of pancreatic protease. Rat brush border membrane proteins were metabolically labeled with [35S]methionine, and isolated brush border membrane was incubated with taurocholate or pancreatic elastase. The activity of solubilized hydrolases was assayed and the molecular forms of the hydrolases were examined by SDS-PAGE. The activity and protein bands of alkaline phosphatase and sucrase-isomaltase were solubilized by taurocholate, while alkaline phosphatase was not solubilized by elastase. Solubilized sucrase-isomaltase molecules were proteolytically degraded by elastase, whereas the intact molecule of sucrase-isomaltase was solubilized by taurocholate. Next the physiological role of bile salts in brush border membrane hydrolase turnover were investigated using metabolic labeling of brush border membrane hydrolase and immunoprecipitation in biliary diversion rats. After three days of biliary diversion, a significant increase in alkaline phosphatase activity was observed. Although synthesis of alkaline phosphatase in biliary diversion rats was similar to that observed in control rats, biliary diversion rats showed 1.5-fold slower turnover of alkaline phosphatase when compared with control rats. These results suggest that conjugated bile salts in the intestinal lumen may cause a rapid turnover of brush border membrane hydrolases, which may be increased by the enhanced enzyme degradation. The mechanisms for the enhanced degradation appeared to be solubilization of hydrolases caused by the detergent activity of bile salts. Therefore, conjugated bile salts may play an important physiological role in the regulation of expression of the protease-resistant enzymes such as alkaline phosphatase.

Alteration of mucosal immunity after long-term ingestion of an elemental diet in rats

The effects of an elemental diet on lymphocyte transport in intestinal lymph and immune responses of gut-associated lymphoid tissue were investigated in rats. The control animals were fed a conventional diet. After 4 week of feeding, the total calorie intake and body weight gain showed no differences between the two groups. The number and total area of Peyer's patches and the ratio of height of villi to height of crypt showed no significant differences between the two groups. The rate of lymph flow in intestinal lymphatics showed no significant change in treated animals compared with the control rats. However, an elemental diet induced a significant decrease in lymphocyte flux in intestinal lymphatics compared with that in control rats. Lymphocyte subsets in intestinal lymph revealed a significant decrease in CD3-positive cells, especially CD4-positive cells in the elemental diet-treated group. A significant decrease in the number of immunoglobulin A-containing cells and a decreased CD4/CD8 ratio in T-cell subsets were observed in the lamina propria of ileal mucosa in the elemental diet-treated group by morphometric analysis in the immunohistochemical study. Specific antibody-secreting cells in intestinal lymph were also investigated after rats were intraduodenally primed with cholera toxin and challenged with the same toxin after an interval of 2 weeks. No significant difference was seen between the two groups in any of the numbers of anti-cholera toxin immunoglobulin-secreting cells in any immunoglobulin A, immunoglobulin G, or immunoglobulin M class as determined by the enzyme-linked immunospot assay.(ABSTRACT TRUNCATED AT 250 WORDS)

In vivo effect of chronic administration of vasoactive intestinal peptide on gut-associated lymphoid tissues in rats

The in vivo effects of chronic administration of vasoactive intestinal peptides (VIP) on the lymphoid cell traffic and the population and function of cells in intestinal lymph and gut-associated lymphoid tissues were examined in rats. VIP was continuously infused from the superior mesenteric artery in rats at a dose of 10 ng/min/kg body weight for 96 h. Lymphocyte transport through intestinal lymph was significantly reduced by VIP without any changes in lymph flow. When lymphocyte subpopulation was examined in intestinal lymph, T cell subsets were decreased with a dominant reduction in the population of helper T cells. T cell subsets were also decreased in mesenteric lymph nodes, but in this case suppressor/cytotoxic T cell subsets were mainly reduced. Despite of the decrease in lymphocyte transport through intestinal lymph and changes of lymphocyte subpopulation, proliferative response of lymphocytes from intestinal lymph and mesenteric lymph nodes to phytohemagglutinin did not show any significant alteration after administration of VIP. By histochemical study on the lamina propria of the small intestine, the population of pan T cells, especially helper T cells, was demonstrated to be significantly decreased after VIP treatment. There was also a marked decrease in the number of immunoglobulin (Ig) A-containing cells in the lamina propria of the small intestine in VIP-treated rats, while no significant changes were seen in the number of IgG and IgM-containing cells. Our present results showed the possibility that a long-term alteration of serum VIP levels could affect the dynamics of immune effector cells and IgA production in gut-associated lymphoid tissues.

Influence of fatty acid absorption on bidirectional release of immunoglobulin A into intestinal lumen and intestinal lymph in rats

Effects of absorption of long and middle chain fatty acids on IgA secretion into the intestinal lumen and intestinal lymph and the factors which evoke changes in IgA secretion during the absorptive process were examined in rat small intestine. Bidirectional secretion of IgA from the intestinal mucosa into the intestinal lumen and intestinal lymph was continuously observed in the control condition. Perfusion of oleic acid (a long-chain fatty acid) micelle into the jejunal loop induced a significant increase in IgA output into the intestinal lymph. In contrast, lymphatic output of IgA was significantly decreased when oleic acid micelle was administered intraduodenally. Absorption of octanoic acid, a middle-chain fatty acid, did not produce any significant changes in IgA output into either direction. CR1505, a CCK-receptor antagonist, significantly attenuated the oleic acid-induced increase in IgA secretion into the intestinal lumen, but did not affect the oleic acid-induced decrease in lymphatic IgA secretion. Pluronic L-81, an inhibitor of chylomicron formation and secretion, significantly attenuated the decrease in IgA output into the intestinal lymph during oleic acid absorption without affecting the luminal IgA output. The rate of release of IgA into the intestinal lumen is stimulated by absorption of long-chain fatty acids possibly through the influence of locally released CCK, while the transport process of IgA into lymphatics is controlled by a different mechanism which is closely correlated with the intracellular formation and secretion of chylomicron.

Attenuation of endotoxin-induced intestinal microcirculatory damage by eicosapentanoic acid

The major objective of this study is to investigate whether oral administration of eicosapentanoic acid (EPA) has any preventive effect on endotoxin-induced microcirculatory damage of rat small intestine. EPA in a daily dose of 300 mg/kg was orally given to male Wistar rats for 3 wk. Submucosal microvessels of the ileum were observed by intravital microscopy equipped with a high-speed video camera system after the intra-arterial infusion of endotoxin at a dose of 2 mg.kg-1.h-1. The number of sticking leukocytes was significantly increased at 30 min after the treatment of endotoxin especially along the smaller branch of intestinal venules. It reached the maximal plateau at 45 min after treatment. The pretreatment of EPA significantly attenuated the increase in sticking leukocytes induced by endotoxin. A platelet-activating factor (PAF) antagonist 2-[N-acetyl-N-(2-methoxy-3-octadecylcarbamoyloxy propoxycarbonyl) aminomethyl]-1-ethylpyridinium chloride (CV-6209) significantly prevented the increased leukocyte sticking to the same extent as EPA treatment. Thirty minutes after endotoxin infusion, red blood cell (RBC) velocity was significantly decreased in both arterioles and venules. RBC velocity appeared to be continuously decreased thereafter and reached its minimum value at approximately 60 min. EPA treatment was revealed to prevent the decrease in RBC velocity of microvessels induced by endotoxin. CV-6209 also significantly attenuated the decreased RBC velocity. The remarkable elevation of PAF content in the ileal mucosa as observed by endotoxin infusion was also significantly attenuated by administration of EPA.(ABSTRACT TRUNCATED AT 250 WORDS)

Significant changes in intestinal lymphatic system and immune response elicited by Peyer's patch excision in adult rats

The effect of deprivation of Peyer's patches (PP) on transport of lymphocytes through intestinal lymph and intestinal mucosal immune responses was investigated in rats. All visible PP in the rat small intestine were excised in order to examine the roles of PP in the intestinal lymphatic system and mucosal immune responses of the intestine. Two weeks after the experimental excision of PP, lymphocyte transport in intestinal lymph was significantly decreased in PP-excised rats without significant changes in lymphocyte subsets as compared with sham operated control rats. Lymphocyte subsets as determined morphometrically in the intestinal mucosa showed no significant alteration in PP-excised rats. There was a significant decrease in the number of immunoglobulin A (IgA) containing cells in the intestinal mucosa of PP-excised rats, while IgM and IgG containing cells showed no statistically significant changes in number. Conversely, the macrophages in the intestinal mucosa increased in number, suggesting the enhanced accessory functions of these macrophages. Antigen-specific immune response was further studied in PP-excised rats using intraduodenal priming and challenge with cholera toxin (CT). Both the determinations of cells producing antigen-specific antibody in the intestinal mucosa using anti-CT antibody and those of cells secreting anti-CT Ig in the intestinal lymph by enzyme-linked immunospot (ELISPOT) assay showed a significant reduction of CT-specific antibody production in PP-excised rats compared with controls. Peyer's patches appear to have an important role in lymphocyte transportation through intestinal lymph and also in mucosal immune responses.

Increased proliferative response of lymphocytes from intestinal lymph during long chain fatty acid absorption

The effect of long chain and medium chain fatty acid absorption on transport and mitogen-induced blast transformation of lymphocytes in intestinal lymphatics was investigated. Intestinal lymph was collected from mesenteric lymph duct cannulated rats maintained in Bollman's cage. Following the intraduodenal administration of oleic acid (long chain fatty acid) or octanoic acid (medium chain fatty acid), only oleic acid produced a significant increase in lymphocyte flux and enhanced proliferative response of lymphocyte in intestinal lymph, without significant alteration of lymphocyte subsets. These changes appeared to be closely correlated with the appearance of radiolabelled oleic acid. Absorption of a medium chain fatty acid, octanoic acid, most of which appeared to be transported to portal blood, did not produce a significant elevation of lymphocyte flux or increased proliferative response of lymphocyte in intestinal lymph. Pluronic L-81, which is a potent inhibitor of the intracellular formation and secretion of chylomicron, significantly attenuated the increased lymphocyte flux and suppressed the enhancement of lymphocyte responsiveness to PHA in intestinal lymph after stimulation by oleic acid administration. There is a possibility that lymphocyte transport and proliferative response in intestinal lymph during oleic acid absorption are closely related to the process of chylomicron formation and secretion to lymphatics in the intestinal mucosa.

Role of platelet activating factor on the fibrinolytic activation in the pathogenesis of gastric mucosal damage induced by endothelin-1

We have examined the hypothesis that the release of tissue type plasminogen activator may play a prominent role in endothelin induced gastric mucosal injury. We determined tissue type plasminogen activator activity in the regional blood sample and the concentration of platelet activating factor in the gastric mucosa after the administration of endothelin-1 in a range of 50-500 pmol/kg into the left gastric artery of male Wistar rats. Endothelin-1 increased the tissue type plasminogen activator release and platelet activating factor formation, and induced subsequent gastric mucosal haemorrhagic change in a dose dependent manner. In addition CV-6209, a selective platelet activating factor blocker, attenuated the activation of regional tissue type plasminogen activator and the development of mucosal damage induced by endothelin-1. The results of this study showed that tissue type plasminogen activator activation may play an important role in the pathogenesis of endothelin induced mucosal injury of rat stomach, and suggest that the platelet activating factor may be involved in the process of regional fibrinolytic activation induced by endothelin-1.

Changes in intestinal absorption of nutrients and brush border glycoproteins after total parenteral nutrition in rats

The effect of total parenteral nutrition on nutrients absorption and glycoprotein changes of brush border membrane was examined in rat small intestine. In total parenteral nutrition rats, a marked decrease in activity of brush border enzymes was observed mainly in the proximal and middle segments of the intestine. Galactose perfusion of jejunal segment showed that hexose absorption was significantly inhibited, while intestinal absorption of glycine or dipeptide, glycylglycine was not significantly affected by total parenteral nutrition treatment. When brush border membrane glycoprotein profile was examined by [3H]-glucosamine or [3H]-fucose incorporation into jejunal loops, significant changes were observed in the glycoprotein pattern of brush border membrane especially in the high molecular weight range over 120 kDa after total parenteral nutrition treatment, suggesting strong dependency of glycoprotein synthesis on luminal substances. Molecular weight of sucrase isomaltase in brush border membrane detected by specific antibody showed no significant difference, however, in total parenteral nutrition and control rats. Also, molecular weight of specific sodium glucose cotransporter of intestinal brush border membrane detected by selective photoaffinity labelling was not altered in total parenteral nutrition rats. It may be that prolonged absence of oral food intake may produce significant biochemical changes in brush border membrane glycoprotein and absorptive capacity of small intestine, but these changes were not observed in all brush border membrane glycoproteins.

Electron microscopy of Mycobacterium leprae in cutaneous nerve components

Cutaneous nerves in lepromatous lesions from ninety-six patients were observed by electron microscopy. The regenerative process of myelinated fibers was evident within lepromatous tissues. Intact or degenerative forms of Mycobacterium leprae were surrounded by the electron transparent substance within the axoplasm and Schwann cell cytoplasm. In contrast, the microenvironment of M. leprae in macrophages was characterized with fusing lysosomes and foamy structures. These results suggest that the electron transparent substance may be derived from bacterial metabolites and also that the foamy structure may originate from lysosomal substance.