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Masaya Sasaki

Publications and source records attributed to Masaya Sasaki.

16 recordsLinked to original sources

Inflixmab as a possible treatment for the hemorrhagic type of Crohn's disease.

Acute lower gastrointestinal bleeding is a rare complication of Crohn's disease (CD). Although anti-tumor necrosis factor-alpha (TNF-alpha, infliximab) therapy has been established for patients with inflammatory and fistulous CD, there has been little evidence on whether infliximab is effective for the hemorrhagic type of CD. We report a case of a 31-year-old man with CD who had recurrent sudden-onset bloody stool. After a second surgery, he visited our hospital because of bloody stool. Infusion of infliximab stopped the bleeding and promoted the healing of ulcers in the ileum and ileocolon anastomosis. We suggest that infliximab therapy should be tried to stop acute gastrointestinal bleeding in CD before there is a surgical emergency.

Adult↗

Suppression of interleukin-1beta- and tumor necrosis factor-alpha-induced inflammatory responses by leukocytapheresis therapy in patients with ulcerative colitis.

BACKGROUND: To elucidate the molecular mechanisms involved in the therapeutic effects of leukocytapheresis (LCAP), we investigated the alterations in the cytokine responses of peripheral blood mononuclear cells (PBMCs) before and after LCAP therapy in ulcerative colitis (UC) patients. METHODS: Twelve patients with UC who did not respond to steroid therapy were enrolled. Nine patients responded to LCAP therapy, but 3 patients did not show clinical improvement. PBMCs were isolated from peripheral venous blood obtained within 5 min before and after the first and second session of LCAP treatment. Cells were stimulated with interleukin (IL)-1beta and tumor necrosis factor (TNF)-alpha for 24 h, and the levels of secreted IL-8 and IL-6 were determined by enzyme-linked immunosorbent assay (ELISA). RESULTS: LCAP induced a significant decrease in peripheral lymphocyte, monocyte, and platelet counts. IL-1beta- and TNF-alpha-induced IL-8 and IL-6 secretion was significantly decreased after the first and second LCAP treatments. These responses were associated with inhibitory effects on nuclear factor (NF)-kappaB DNA-binding activity. CONCLUSIONS: LCAP downregulates the IL-1beta- and TNF-alpha-induced inflammatory responses in PBMCs isolated from UC patients. The induction of hyporesponsiveness to proinflammatory cytokines may be an important factor mediating the clinical effects of LCAP in UC patients.

Adult↗

Natriuretic peptides up-regulate aquaporin 3 in a human colonic epithelial cell line.

Several specialized channels termed aquaporins (AQPs) facilitate water transport in the gastrointestinal tract. AQP3 localizes to epithelial cells in the human small intestine and colon. However, the regulatory mechanisms responsible for AQP3 function in the gastrointestinal tract are not well understood. To characterize the regulation of AQP3 expression by atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP), we studied mRNA expression by Northern blotting, protein expression by Western blotting and DNA binding activity by electrophoretic mobility shift assay (EMSA) in the human colonic epithelial cell line HT-29. We also used several inhibitors to investigate signal transduction. AQP3 mRNA was up-regulated in addition to ANP (>100 nM) and BNP (>10 nM). The expression of AQP3 protein was enhanced at 1 h after the addition of ANP and BNP. The combination of protein kinase-A (PK-A) and protein kinase-G (PK-G) inhibitors completely inhibited the expression of AQP3 mRNA enhanced by ANP or BNP to its basal level. The EMSA of the cyclic-AMP response element (CRE) in HT-29 cells revealed a single band. These results indicate that ANP and BNP up-regulated the expression of AQP3 mRNA and protein, and both PK-A and PK-G dependent pathways mediated this effect.

Aquaporin 3↗

A novel diamino-pyridine derivative (IS-741) attenuates rat ileitis induced by trinitrobenzene sulfonic acid.

BACKGROUND: The etiology and pathogenesis of inflammatory bowel disease remain unknown. However, neutrophil infiltration into the inflammatory lesion is an important process in inflammatory bowel disease. In this study, we used rat trinitrobenzene sulfonic acid (TNBS) ileitis as a Crohn's disease model, and investigated the effects of oral IS-741 (which inhibits the expression of Mac-1, a cell adhesion molecule) on leukocyte-endothelial interactions. METHODS: Rat ileitis was induced by the intraluminal injection of a TNBS solution (160 mg/kg in 50% ethanol) at a site 10 cm proximal to the ileocecal valve. The rats then received oral IS-741 (50 mg/kg) or saline for 7 days. On the day 8 after the initial administration of IS-741 or saline, we determined the visible damage score, and assessed myeloperoxidase (MPO) activity. Concentrations of cytokines in the ileum, such as interleukin-8 (IL-8) and tumor necrosis factor-alpha (TNF-alpha) were assayed by enzyme-linked immunosorbent assay (ELISA). We also investigated the infiltration of polymorphonuclear cells and Mac-1 positive cells by histological examinations. RESULTS: The administration of IS-741 resulted in a significant reduction of the visible damage score, myeloperoxidase (MPO) activity, and mucosal IL-8 levels in the ileum as compared with the saline administration. IS-741 also dramatically reduced the infiltration of polymorphonuclear cells and Mac-1 positive cells into the inflamed lesions. CONCLUSIONS: These results indicate that the oral administration of IS-741 inhibits neutrophil infiltration into inflamed lesions, and is effective for attenuating rat TNBS ileitis. This new anti-inflammatory agent may be beneficial for the treatment of inflammatory bowel disease.

Animals↗

A comparison of the effects of medium- and long-chain triglycerides on neutrophil stimulation in experimental ileitis.

BACKGROUND: In ileitis, the chain length of dietary fats affects inflammation, and medium-chain triglycerides (MCTs), but not long-chain triglycerides (LCTs), reduce intestinal damage. The mechanism of this effect has not been fully elucidated. In this work, we studied the effects of MCTs and LCTs on polymorphonuclear neutrophil (PMN) action in trinitrobenzene sulfonic acid (TNB)-induced ileitis. METHODS: Twelve-week-old male Sprague-Dawley (SD) rats received TNB in the ileal lumen and were then fed MCTs or LCTs for 3 days. RESULTS: We detected no significant differences in the morphological damage between the MCT and the LCT groups. The content of interleukin (IL)-8, on the other hand, was significantly lower in the MCT group than in the LCT group, as was myeloperoxidase activity. The CD11b expression by PMNs was higher in the LCT group, but the difference was not of statistical significance. CONCLUSIONS: These findings suggested that proinflammatory activity was greater in the LCT group in comparison with the MCT group.

Animals↗

Supplement of a chitosan and ascorbic acid mixture for Crohn's disease: a pilot study.

OBJECTIVE: Although the pathogenesis of Crohn's disease remains unclear, dietary fat is thought to exacerbate intestinal inflammation. Chitosan is a water-insoluble dietary fiber, and a chitosan and ascorbic acid mixture has been shown in rats to increase fecal fat excretion without affecting protein digestibility. However, it remains unclear whether a chitosan and ascorbic acid mixture is safe and effective for patients with Crohn's disease. We designed a pilot trial to investigate the tolerability and amount of fat excretion after the oral administration of a chitosan and ascorbic mixture for inactive Crohn's disease. METHODS: Eleven outpatients were given seven tablets daily of a chitosan and ascorbic mixture (chitosan was given at 1.05 g/d) for 8 wk. Patients did not interrupt their respective therapies for Crohn's disease. RESULTS: The bowel movements of most patients increased slightly during the study. Nutritional and inflammatory markers in patients did not differ before and after treatment. The chitosan and ascorbic acid mixture significantly increased the fat concentration in the feces during treatment. CONCLUSIONS: These results indicated that oral administration of a chitosan and ascorbic acid mixture in patients with Crohn's disease is tolerable and increases fecal fat excretion without affecting disease activity.

Adult↗

Dietary fat attenuates the benefits of an elemental diet in active Crohn's disease: a randomized, controlled trial.

OBJECTIVES: Although an elemental diet has been established as the primary treatment for patients with Crohn's disease, the influence of dietary fat on the elemental diet remains unclear. We have designed the first randomized, controlled trial for elemental diets containing different fat percentages in patients with active Crohn's disease. METHODS: Each patient was randomized to receive one of three dose levels of fat in an elemental diet (Elental) for 4 weeks: 10 patients received low fat (3.06 g/day), 10 patients received medium fat (16.56 g/day) and eight patients received high fat (30.06 g/day). The additional fat was composed of long-chain fatty acids. All patients were evaluated using the International Organization of Inflammatory Bowel Disease rating, plus C-reactive protein level and erythrocyte sedimentation rate, which were measured at weekly intervals. RESULTS: Although the International Organization of Inflammatory Bowel Disease rating, C-reactive protein level and erythrocyte sedimentation rate in the low-fat group decreased, the values in the medium- and high-fat groups fluctuated during the study. The remission rate after 4 weeks in each group was 80%, 40% and 25% for patients in the low-, medium- and high-fat groups, respectively. CONCLUSIONS: When the fat consisted of long-chain triglycerides, a high amount of this fat in the elemental diet formula decreased its therapeutic effect against active Crohn's disease.

Adult↗

The effects of lectins on indomethacin-induced small intestinal ulceration.

Growth factors, such as epidermal growth factor and keratinocyte growth factor, have considerable therapeutic potential for repairing mucosal injury in the intestine when given systemically. Recently, several lectins have been shown to have trophic effects on the intestine when given orally. We examined the effects of phytohaemagglutinin (PHA) and concanavalin A (Con-A) on indomethacin-induced intestinal injury in rat. Five-week-old rats were randomized to four groups (n=5), and intestinal injury was induced by indomethacin injection in three of these groups. Elemental diet (ED) feeding was then commenced. The groups were thus ED feeding/indomethacin untreated (control group), ED feeding/indomethacin treated (ED group), 0.1% PHA-supplemented ED feeding/indomethacin treated (PHA group) and 0.1% Con-A-supplemented ED feeding/indomethacin treated (Con-A group). After 7 days of feeding, macroscopic inflammatory scores, mucosal permeability, myeloperoxidase (MPO) activities and cell proliferation were determined. Macroscopic inflammatory scores, mucosal permeability and MPO activities were significantly lower in both lectin groups than that in control group. Twenty-four hour excretion rate of phenolsulphonphthalein was significantly lower in both lectin groups than that in ED group. Cell proliferation of the small intestine was significantly increased by both lectins. Lectin supplementation can induce ulcer healing following indomethacin-induced damage.

Animals↗

Keratinocyte growth factor and epidermal growth factor can reverse the intestinal atrophy associated with elemental diets in mice.

Elemental diets are associated with intestinal atrophy and reduced intestinal integrity. Growth factors such as keratinocyte growth factor (KGF) and epidermal growth factor (EGF) have considerable potential for the therapeutic reversal of such atrophy and may have greater actions if given in combination. We examined the effects of recombinant human KGF (rHuKGF), EGF and their combination on tissue mass, cell proliferation and crypt fission throughout the intestine of mice fed elemental diets. rHuKGF significantly increased the relative wet weight of the intestine, with EGF having a lesser effect. Cell proliferation of the stomach, small intestine and colon were significantly increased by rHuKGF, but EGF only increased proliferation in the small intestine. Crypt fission in the small intestine and colon was significantly decreased by rHuKGF. An interactive effect of rHuKGF and EGF on the weight of stomach and the proliferation of the fundus and antrum was observed. Moreover, an interactive effect of the agents was also seen on crypt fission in the colon. We concluded that (1) rHuKGF and EGF have significant trophic effects on the stomach, small intestine and colon, (2) these actions vary between different sites in the gastrointestinal tract, and (3) interactive effects occur.

Animals↗

Effects of the soluble fibre pectin on intestinal cell proliferation, fecal short chain fatty acid production and microbial population.

AIM: Although pectin, a dietary fibre, has been suggested to possess some trophic effects on the intestine, the mechanisms involved remain unclear. This study aimed to evaluate the effects of pectin on rat intestinal cell proliferation and the intraluminal environment. METHODS: Control and pectin-fed rats were given a fibre-free elemental diet (ED) and an ED containing 2.5% pectin, respectively. On the 15th day, the length, weight and number of Ki-67-positive cells from each intestinal segment, and the short chain fatty acids (SCFAs) and microbial population in the caecum were measured. Plasma glucagon-like peptide-2 (GLP-2) concentration and GLP-2 receptor (GLP-2R) mRNA levels in the epithelium were also determined. RESULTS: Pectin supplementation resulted in significant increases in the length, weight, and number of Ki-67-positive cells in the ileum, caecum and colon. Although pectin supplementation did not affect the caecal microbial flora that produced SCFAs, the caecal SCFA content was significantly increased. Pectin supplementation also induced an increase in the plasma GLP-2 concentration, but did not affect the GLP-2R mRNA levels in the small intestine. CONCLUSIONS: The increases in the caecal SCFAs and plasma GLP-2 levels induced by pectin supplementation may cause mucosal proliferation in the lower intestinal tract.

Animals↗

Mucosal permeability regulates receptor binding of luminal epidermal growth factor in the adult rat intestine.

Epidermal growth factor (EGF) stimulates repair in the damaged intestine, but its role in the normal intestine is not clear. Because EGF receptors are found on the basolateral surface but not the luminal surface, we hypothesized that mucosal permeability regulates EGF binding. Adult male rats were divided into 3 groups, one that was fed normal chow (the control), one that was starved for 4 days, and one that was given methotrexate (MTX) intragastrically (10 mg/kg/day for 3 days). The rats were sacrificed and everted sacks of the jejunum were made and incubated in EGF solution. Western blot analysis of mucosal homogenates showed that the amount of phosphotyrosyl EGF receptor in the starved and MTX-treated groups was, respectively, about 1.5 times and 2 times that in the control group. The mucosal permeability in the starved and MTX treated groups also increased and varied directly with the amount of phosphotyrosyl EGF receptor. These results suggest that in the adult rat intestine, luminal EGF may play a role only under tissue damage, where enhanced permeability permits the EGF to pass through the mucosa and bind to its receptor on the basolateral membrane.

Animals↗

N-3 fatty acid-rich diet prevents early response of interleukin-6 elevation in trinitrobenzene sulfonic acid-induced enteritis.

Dietary fat is an important factor involved in the pathogenesis of inflammatory bowel disease (IBD). It remains unclear how n-3 and n-6 fatty acids modulate intestinal inflammation. In this study, we investigated the effects of n-3 and n-6 fatty acid-rich diets on trinitrobenzene sulfonic acid (TNBS)-induced enteritis. The rats were fed an n-3 or n-6 rich-diet for 12 days, and then starved for the following 2 days. An intraileal injection of TNBS was administered, and TNBS-enteritis subsequently developed. Macroscopic and histological examination was performed after 24 h. Serum cytokine levels were determined by ELISA. The n-6 fatty acid-rich diet markedly enhanced mucosal damage as compared to the n-3 fatty acid-rich diet. The damage score was significantly higher in the n-6 fatty acid-rich diet group (P<0.05). Histological changes in the mucosa were more severe in the n-6 fatty acid-rich diet group than in the n-3 fatty acid-rich group. Serum IL-6 levels were significantly higher in the n-6 fatty acid-rich diet group than in the n-3 fatty acid-rich group (P<0.05). On the other hand, there were no differences in serum TNF-alpha levels. The n-3 fatty acid-rich diet effectively reduced early mucosal inflammation in TNBS enteritis. The effects of the n-3 fatty acids were associated with blockage of mucosal IL-6 secretion. Our data suggest that n-3 fatty acid-rich diet may be applicable for enteral nutrition in the treatment of IBD patients.

Animal Feed↗

Elevated serum anti-carbonic anhydrase II antibodies in patients with ulcerative colitis.

An autoimmune mechanism has been postulated for the pathogenesis of ulcerative colitis (UC). The aim of this study was to evaluate the presence of anti-carbonic anhydrase (CA) I and anti-CA II antibodies in a series of inflammatory bowel disease (IBD) patients. We studied 58 IBD patients [36 UC patients and 21 patients with Crohn's disease (CD)]. As a control, 24 healthy individuals and 12 patients with non-IBD diarrheal diseases were tested. Serum anti-CA I and anti-CA II antibodies were quantified by enzyme-linked immunosorbent assay. Anti-CA II antibody was detected in 27.8% of UC patients, whereas anti-CA I antibody was detected in only 5.6% of UC patients. Positive rate of anti-CA II antibody was significantly higher in UC patients as compared to the control. In CD patients and non-IBD diarrheal patients, there were no significant increase in positive rate of either anti-CA I or II antibody. These results suggest that autoimmune responses against CA II may be involved in the pathogenesis of UC, and similar mechanism may participate in the development of pancreatic lesions in UC patients.

Adult↗

Alteration in expression of polyamine and glucose-related enzyme mRNA after small bowel resection in the rat residual ileum.

The adaptive hyperplasia of the residual intestine after a massive bowel resection is not fully understood. We investigated the alterations in polyamine and glucose-related enzyme mRNA expression during intestinal adaptation. Six-week-old male Wistar rats underwent an 80% resection of the small intestine. The residual ileum was removed on the preoperative day (control) and on postoperative day (POD) 1, 3, 5 and 7. The total RNA was extracted from the mucosa, and a Northern blot analysis was performed. In the residual small intestine, the expression of polyamine synthesis enzymes, ornithine decarboxylase (ODC) and S-adenosylmethionine decarboxylase (SAMDC) mRNAs were increased on POD 1. The expression of polyamine degradation enzymes diamine oxidase (DAO) and spermidine/spermine N1-acetyltransferase (SSAT) mRNA did not change dramatically. Antizyme-1 (AZ-1) mRNA was significantly increased on POD 1. The mRNA expression of glucose absorption and metabolism-related proteins, including the Na+-dependent D-glucose cotransporter (SGLT1), fructose-6-phosphate,2-kinase/fructose-2,6-bisphosphatase (Fru-6-P,2-kinase/Fru-2,6-Pase) and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) were only slightly changed on POD 1. The enzymes responsible for polyamine biosynthesis but not catabolism were upregulated at the translational level in enterocytes after a small bowel resection. The expression of glucose transport and glycolysis enzyme mRNAs did not increase after a small bowel resection.

Adenosylmethionine Decarboxylase↗