G. D'Argenio

Butyrate, mesalamine, and factor XIII in experimental colitis in the rat: Effects on transglutaminase activity

BACKGROUND/AIMS Butyrate and factor XIII may improve ulcerative colitis; they also affect tissue and serum transglutaminase levels. We investigated the therapeutic potential of sodium butyrate and factor XIII and the role of transglutaminase during mucosal repair in experimental colitis. METHODS Rats with induced colitis were treated with sodium butyrate, mesalamine, sodium butyrate plus mesalamine, or saline enemas. Thromboxane B2 was monitored as index of inflammation. In a fifth group, the effectiveness of intravenous Factor XIII was assessed. RESULTS Sodium butyrate, alone or plus mesalamine, reduced histological activity from 13.7 +/- 1.7 (saline) to 2.5 +/- 1.3 and 2.3 +/- 1.1 (P < 0.01), respectively. Transglutaminase, reduced in the colons of the saline group (783 +/- 157 vs. normal 1800 +/- 192 mU/g; P < 0.01), returned toward normal values in the sodium butyrate or sodium butyrate plus mesalamine groups (1390 +/- 228 and 1226 +/- 172 mU/g, respectively; P < 0.01 vs. saline). Furthermore, sodium butyrate plus mesalamine reduced thromboxane B2 levels by day 5 (0.92 +/- 0.16 vs. saline 1.85 +/- 0.34 ng/mL; P < 0.05). Factor XIII therapy improved the histological picture (2.7 +/- 2.1 vs. saline 13.8 +/- 1.7; P < 0.01) and increased transglutaminase levels both in serum (2.81 +/- 0.11 vs. saline 1.45 +/- 0.09 mU/mL; P < 0.01) and in colon (1503 +/- 127 vs. saline 747 +/- 103). CONCLUSIONS Sodium butyrate and factor XIII improve colitis, sodium butyrate plus mesalamine reduce early thromboxane B2 synthesis, and transglutaminase(s) plays a role in ulcer healing.

Transglutaminases in Crohn's disease.

Transglutaminases are a family of Ca-dependent enzymes involved in various biological events. Circulating transglutaminase (factor XIIIa) is decreased in blood of patients with inflammatory bowel diseases. There is evidence that factor XIIIa and tissue type transglutaminase, present in cell cytosol, bind to various proteins of the extracellular matrix. This study examined the value of serum transglutaminase assay in the treatment and follow up of Crohns disease and then investigated the intestinal location of both forms of transglutaminases by immunohistochemistry in normal and abnormal tissues. Serum transglutaminase activity was assayed in 36 patients with active Crohns disease (CDAI > 150). Eighteen patients were studied prospectively from relapse into remission. A significant inverse correlation (p < 0.001) was found between circulating transglutaminase and Crohns disease activity index; a correlation was also found between serum transglutaminase and serum orosomucoid (p < 0.01) and C reactive protein (p < 0.01). Patients were prospectively studied until clinical remission showed improvement in both their CDAI score mean (SD) (230 (46) to 72 (34), p < 0.01) and transglutaminase activity mean (SD) (0.61 (0.12) to 0.93 (0.13) mU/ml, p < 0.01). The immunohistochemistry assessment showed a colocalisation of factor XIIIa and tissue transglutaminase to the extracellular matrix of damaged tissues. In conclusion, these data confirm the value of serum transglutaminase assay as marker of Crohns disease activity, extend the utility of serum transglutaminase assay to follow up of the disease, and emphasised the role of different types of transglutaminases in extracellular matrix assembly in the damaged tissues.

Esophageal impairment in adult celiac disease with steatorrhea

Objective:A high prevalence of reflux esophagitis in celiac children and gut motor disorders in adult patients have been described. The aim of this study is to investigate the prevalence of esophageal symptoms and the esophageal motility pattern in adult celiac patients before and after gluten-free diet.Methods:In 22 consecutive adult celiac patients, before and after gluten-free diet, and in controls we calculated an esophageal symptom score regarding heartburn, regurgitation, dysphagia, and chest pain, and performed esophageal manometry using a constantly perfused multilumen catheter.Results:Patients were divided into two groups: with and without steatorrhea. Before gluten-free diet, the prevalence of esophageal symptoms was 45.5% in all patients, but was significantly higher in patients with steatorrhea than in those without and in 44 control subjects (80%vs 16.7% and 27%, p < 0.05). Lower esophageal sphincter pressure was 17.5 ± 5.3 in all patients, but was significantly lower in patients with steatorrhea than in patients without steatorrhea and 11 controls subjects (13.1 ± 4.1 vs 21.0 ± 2.9 and 20.7 ± 3.7 mm Hg (mean ± SD, p < 0.05). After the diet, the prevalence of esophageal symptoms diminished in all patients (9%vs 45.4%, p < 0.05) and lower esophageal sphincter pressure, measured in 13 patients, increased (19.0 ± 3.7 vs 15.7 ± 5.3 mm Hg, p < 0.05).Conclusion:Adult celiac patients with steatorrhea present a higher prevalence of esophageal symptoms and a lowered lower esophageal sphincter pressure compared with celiac patients without steatorrhea and control subjects, but these phenomena can be reverted to control levels by gluten-free diet.

Diamine Oxidase in Rat Small Bowel: Distribution in Different Segments and Cellular Location

Diamine oxidase (DAO) is an enzyme with high activity found in the small bowel mucosa of the rat and man, and only with very low activity in all other tissues. The present study was designed to investigate the enzymatic distribution along 8 consecutive small bowel segments of mucosa and to test the DAO concentration on brush border membranes obtained from whole mucosal homogenate in Wistar rats. Our data document that DAO activity is mainly distributed in intermediate and distal small bowel segments and is not significantly associated with enterocyte brush border.

Human serum transglutaminase and coeliac disease: correlation between serum and mucosal activity in an experimental model of rat small bowel enteropathy.

Transglutaminase (TG) activity is increased in the mucosa of patients with coeliac disease. Among 18 patients with untreated coeliac disease we have found a significant decrease (p less than 0.001) in serum levels of TG activity (0.72 (0.23) mU/ml). There was no significant differences between 16 treated coeliacs (1.24 (0.28) mU/ml) and 30 normal controls (1.63 (0.42) mU/ml). To evaluate the connection between serum and mucosal TG activity we used the experimental model of methotrexate induced acute hypoplastic enteropathy in the rat. Transglutaminase activity was unchanged in serum and mucosa 24 and 48 hours after MTX administration, but increased in mucosa (2.606 (0.95) v basal 0.207 (0.026) mU/mg protein, p less than 0.001) and significantly decreased in serum at 72 hours (2.08 (0.38) v basal 5.56 (1.50) mU/ml, p less than 0.001) during intestinal cell proliferation. Activity of the enzyme in the mucosa and serum returned to baseline levels within 120 hours. This experimental animal model helps to explain the data of TG activity in human intestinal mucosa and serum reported in this study. Results are mean (SD).

Transglutaminase activity along the rat small bowel and cellular location.

A recent report indicates a relationship between human transglutaminase (TG) jejunal mucosa activity and celiac disease. We investigated the enzyme distribution along six consecutive small bowel segments of mucosa and tested TG activity on brush border membranes obtained from whole mucosa homogenate in Wistar rats. TG activity was significantly present in jejunal mucosa even if mostly detected in the distal part of small intestine. Our study indicates highest enzymatic activity in the subcellular fraction containing organelles and cellular membranes (66.8%) while a 7% activity was associated with the brush border fraction.

Metabolic fate of plasma diamine oxidase: evidence of isolated and perfused rat liver uptake

After injection of an intravenous bolus of heparin (15,000 IU) in two groups of subjects, 10 normal volunteers and 6 subjects with external biliary drainage, blood and urine samples were collected; in the latter group bile samples were collected also. All samples were assayed for diamine oxidase (DAO). Persistently high values of this enzyme were found in plasma of both populations after heparin stimulation, while no increase in enzymatic activity was detected in bile and urine. In order to confirm and support the hepatic clearance of DAO, liver uptake of the enzyme derived from porcine kidney, human plasma and human placenta was studied by perfusion of isolated rat liver. Disappearance curves of the enzyme derived from three different sources showed a prompt liver uptake: activity decreased by about 50% in 10 min (endocytic uptake) and a slower but constant reduction during the remaining 110 min of perfusion was observed. These data suggest the hypothesis of liver metabolism of plasma DAO.

Serum transglutaminase in inflammatory bowel diseases

We evaluated the serum transglutaminase activity in patients with inflammatory bowel diseases (IBD) to correlate its level with clinical status. There were 49 patients with Crohns disease (CD), 50 with ulcerative colitis (UC), 35 with diseases other than IBD as control group and 42 healthy subjects matched for sex and age. Enzyme activity was significantly lower in both IBD groups than in controls and in normal subjects (p less than 0.001); we found a significant negative correlation between serum transglutaminase (TG) activity and clinical severity of the disease in both IBD patient groups (r = -0.54 in CD, and r = -0.69 in UC). Moreover, in UC and CD patients, a serum TG value lower than 0.80 mU/ml retrospectively proved to predict the need for major surgery and/or total parenteral nutrition. These results suggest that serum TG may prove useful in the management of inflammatory intestinal diseases in predicting clinical outcome.

Transglutaminase in azoxymethane-induced colon cancer in the rat

A widespread form of transglutaminase, tissue transglutaminase, has been identified in a number of mammalian cell types, both normal and transformed cells; its biological role is not well understood. We investigated the effect of experimentally induced colon cancer on transglutaminase activity in the rat. Azoxymethane (15 mg/kg for six weeks), given by a course of weekly intraperitoneal injections, produces tumors almost exclusively confined to the intestinal tract. Transglutaminase activity was assayed on tissue homogenates both during the period of treatment and, when the cancer had developed, on tumor tissue and on macroscopically uninjured adjacent tissue. A transient proliferative phase was present in the intestine during azoxymethane treatment: in this phase we found a coincidentally increased transglutaminase levels. Transglutaminase activity in tumors of both small and large intestine was significantly higher than in adjacent tissue. Immunohistochemistry revealed higher levels of transglutaminase in tumors, mainly localized in the extracellular matrix, than in adjacent tissues, where it was widely distributed. The present study shows that transglutaminase, besides its potential role in intracellular process during early proliferative phase of carcinogenesis, may also play an important role in matrix processing during tumor growth and differentiation.

Behaviour of transglutaminase activity in intestine of starved and refed rats.

Starvation causes an intestinal mucosa atrophy which is greater in jejunum than in ileum. Hypoplasia is promptly reversed by refeeding. Transglutaminase (TG) has been controversially implicated in cell proliferation and its role in intestine is not defined. We investigate, by the above described model, the behaviour of TG in proximal and distal small bowel as well as in colon of rats after 4 days of starvation and at day 1, 2, 3, 4, 5, 7 and 10 of refeeding. Our results emphasize a significative reduction of TG in small bowel induced by starvation (day 0) and a prompt recovery of the enzyme activity after refeeding; furthermore, in the first intestinal tract TG activity reaches from day 2 to day 5 values which are significantly higher than basal. Four days of starvation do not affect TG in colon. In conclusion, our study demonstrates that in rats high values of TG activity are coincident with the intense proliferative phase in small intestine subsequent to starvation atrophy.