Intestinal Alkaline Phosphatase Attenuates Alcohol-Induced Hepatosteatosis in Mice.

BACKGROUND AND AIMS: Bacterially derived factors from the gut play a major role in the activation of inflammatory pathways in the liver and in the pathogenesis of alcoholic liver disease. The intestinal brush-border enzyme intestinal alkaline phosphatase (IAP) detoxifies a variety of bacterial pro-inflammatory factors and also functions to preserve gut barrier function. The aim of this study was to investigate whether oral IAP supplementation could protect against alcohol-induced liver disease. METHODS: Mice underwent acute binge or chronic ethanol exposure to induce alcoholic liver injury and steatosis ± IAP supplementation. Liver tissue was assessed for biochemical, inflammatory, and histopathological changes. An ex vivo co-culture system was used to examine the effects of alcohol and IAP treatment in regard to the activation of hepatic stellate cells and their role in the development of alcoholic liver disease. RESULTS: Pretreatment with IAP resulted in significantly lower serum alanine aminotransferase compared to the ethanol alone group in the acute binge model. IAP treatment attenuated the development of alcohol-induced fatty liver, lowered hepatic pro-inflammatory cytokine and serum LPS levels, and prevented alcohol-induced gut barrier dysfunction. Finally, IAP ameliorated the activation of hepatic stellate cells and prevented their lipogenic effect on hepatocytes. CONCLUSIONS: IAP treatment protected mice from alcohol-induced hepatotoxicity and steatosis. Oral IAP supplementation could represent a novel therapy to prevent alcoholic-related liver disease in humans.

Vitamin D prevents the intestinal fibrosis via induction of vitamin D receptor and inhibition of transforming growth factor-beta1/Smad3 pathway.

BACKGROUND AND AIMS: Vitamin D deficiency in patients with inflammatory bowel disease (IBD) is associated with greater disease activity and lower quality of life. Intestinal fibrosis is a main complication of IBD. However, the effect of vitamin D on intestinal fibrosis remains unclear. We investigated the prophylactic effect and the underlying mechanism of vitamin D on the intestinal fibrosis in vitamin D-deficient mice with chronic colitis. METHODS: Vitamin D-deficient mice were randomized into two groups receiving the vitamin D-deficient or vitamin D-sufficient diet from weaning (week 4). Intestinal fibrosis was induced by six-weekly 2,4,6-trinitrobenzene sulfonic acid administrations from week 8. At week 14, the productions of extracellular matrix (ECM) and total collagen were measured in the colons, and TGF-ß1/Smad3 signal transduction was examined in isolated colonic subepithelial myofibroblasts (SEMF). The expression of vitamin D receptor (VDR), α-SMA and Collagen I in normal SEMF and VDR-null SEMF exposed to TGF-ß1 and/or 1,25(OH)2D3 was measured. RESULTS: Vitamin D significantly reduced the histological scoring, ECM and collagen productions in the colons and decreased the levels of TGF-ß1, Smad-3, p-Smad3 and Collagen I in SEMF. 1,25(OH)2D3-induced VDR expression and decreased TGF-ß1-stimulated α-SMA and Collagen I expressions in SEMF. Knocking down VDR expression in SEMF abolished the effect of 1,25(OH)2D3. CONCLUSIONS: Vitamin D has prophylactic effect on intestinal fibrosis in the vitamin D-deficient mice with chronic colitis, which may be associated with the inhibited activation of TGF-ß1/Smad3 pathway in the SEMF via VDR induction.

A novel approach to maintain gut mucosal integrity using an oral enzyme supplement.

OBJECTIVE: To determine the role of intestinal alkaline phosphatase (IAP) in enteral starvation-induced gut barrier dysfunction and to study its therapeutic effect as a supplement to prevent gut-derived sepsis. BACKGROUND: Critically ill patients are at increased risk for systemic sepsis and, in some cases, multiorgan failure leading to death. Years ago, the gut was identified as a major source for this systemic sepsis syndrome. Previously, we have shown that IAP detoxifies bacterial toxins, prevents endotoxemia, and preserves intestinal microbiotal homeostasis. METHODS: WT and IAP-KO mice were used to examine gut barrier function and tight junction protein levels during 48-hour starvation and fed states. Human ileal fluid samples were collected from 20 patients postileostomy and IAP levels were compared between fasted and fed states. To study the effect of IAP supplementation on starvation-induced gut barrier dysfunction, WT mice were fasted for 48 hours +/- IAP supplementation in the drinking water. RESULTS: The loss of IAP expression is associated with decreased expression of intestinal junctional proteins and impaired barrier function. For the first time, we demonstrate that IAP expression is also decreased in humans who are deprived of enteral feeding. Finally, our data demonstrate that IAP supplementation reverses the gut barrier dysfunction and tight junction protein losses due to a lack of enteral feeding. CONCLUSIONS: IAP is a major regulator of gut mucosal permeability and is able to ameliorate starvation-induced gut barrier dysfunction. Enteral IAP supplementation may represent a novel approach to maintain bowel integrity in critically ill patients.

Intestinal alkaline phosphatase promotes gut bacterial growth by reducing the concentration of luminal nucleotide triphosphates.

The intestinal microbiota plays a pivotal role in maintaining human health and well-being. Previously, we have shown that mice deficient in the brush-border enzyme intestinal alkaline phosphatase (IAP) suffer from dysbiosis and that oral IAP supplementation normalizes the gut flora. Here we aimed to decipher the molecular mechanism by which IAP promotes bacterial growth. We used an isolated mouse intestinal loop model to directly examine the effect of exogenous IAP on the growth of specific intestinal bacterial species. We studied the effects of various IAP targets on the growth of stool aerobic and anaerobic bacteria as well as on a few specific gut organisms. We determined the effects of ATP and other nucleotides on bacterial growth. Furthermore, we examined the effects of IAP on reversing the inhibitory effects of nucleotides on bacterial growth. We have confirmed that local IAP bioactivity creates a luminal environment that promotes the growth of a wide range of commensal organisms. IAP promotes the growth of stool aerobic and anaerobic bacteria and appears to exert its growth promoting effects by inactivating (dephosphorylating) luminal ATP and other luminal nucleotide triphosphates. We observed that compared with wild-type mice, IAP-knockout mice have more ATP in their luminal contents, and exogenous IAP can reverse the ATP-mediated inhibition of bacterial growth in the isolated intestinal loop. In conclusion, IAP appears to promote the growth of intestinal commensal bacteria by inhibiting the concentration of luminal nucleotide triphosphates.

[Maintenance effect of polyglycosides of Tripterygium wilfordii on remission in postoperative Crohn disease].

OBJECTIVE: To observe the maintenance effect of polyglycosides of Tripterygium wilfordii (GTW) on remission in postoperative Crohn disease (CD). METHODS: From 2005 to 2007, 45 adult cases of postoperative Crohn disease were randomly divided into two groups, GTW group and mesalazine group, which received GTW and mesalazine treatment respectively. CD activity index (CDAI) and clinical markers were collected at 0, 3, 6, 12 months or at the onset of symptoms. Ileocolonoscopy was performed at the end of the trial (1 year after operation) or at the onset of symptoms, and recurrence score were recorded. RESULTS: No clinical recurrence was ascertained in both groups at 3 months. Four patients (18.2%) in GTW group relapsed and 5 (21.7%) in mesalazine group relapsed at 6 months (P=0.530). Seven patients (31.8%) in GTW group and 9 (39.1%) in mesalazine group relapsed at one year (P=0.421). Ten patients (45.5%) in GTW group had endoscopic recurrence compared with 14 (60.9%) in mesalazine group at one year(P=0.231). There were no significant differences between two groups. CONCLUSION: GTW is similar to mesalazine in maintenance of remission of postoperative Crohn disease.

Efficacy of T2 in active Crohn's disease: a prospective study report.

To date few therapies have been shown to reliably prevent the evolution of Crohn's disease (CD). The traditional Chinese medicine, Tripterygium wilfordii Hook F (TWHF), has both immunomodulatory and anti-inflammatory activities. Our aim was to investigate the potential efficacy of T2, the major constituent of extracts of TWHF, in inducing remission of active CD. Twenty adult patients with active CD were enrolled to be treated with T2 pills (60 mg daily) for 12 weeks. Plasma levels of C-reactive protein (CRP), tumor necrosis factor (TNF)-alpha, and interleukin (IL)-1beta were measured at entry and every 2 weeks thereafter until week 12. At each visit the CD Activity Index (CDAI) was calculated. The CD Endoscopic Index of Severity was measured at entry and week 12. Sixteen patients completed the study. A significant decrease in serum levels of CRP, TNF-alpha, and IL-1beta occurred rapidly after commencement of treatment. CDAI scores showed a rapid decline during the first 8 weeks and reached their lowest at week 10. Endoscopic improvements were observed at week 12. In conclusion, T2 appears to be effective for the treatment of mildly or moderately active CD. Further controlled studies are warranted for this promising drug.

Triptolide suppresses IL-1beta-induced chemokine and stromelysin-1 gene expression in human colonic subepithelial myofibroblasts.

AIM: To examine the inhibitive effects of triptolide on the expression of IL-8, monocyte chemotactic protein (MCP)-1, and matrix metalloproteinases (MMP)-3 in subepithelial myofibroblasts (SEMF) stimulated with IL-1beta. METHODS: SEMF cultures were established from normal colons in patients who underwent gut resection for colorectal carcinoma. Chemokine and MMP-3 expressions were determined by ELISA and RT-PCR. The cytosolic amount of phosphorylation of I kappa B-alpha(p-I kappa B-alpha) was determined by Western blotting. The DNA binding capacity of NF-kappa B was evaluated by electrophoretic mobility shift assays. RESULTS: IL-1beta stimulated protein and mRNA expression of IL-8, MCP-1, and MMP-3 in SEMF. Triptolide inhibited these effects of IL-1beta in a dose-dependent manner. Mechanistic studies revealed that triptolide markedly decreased IL-1beta -induced NF-kappa B DNA binding capacity and cytosolic amount of p-I kappa B-alpha. These results showed that triptolide inhibited IL-1beta -induced chemokine and MMP-3 expression in SEMF through the NF-kappa B pathway. CONCLUSION: Triptolide inhibited IL-1beta -induced chemokine and MMP-3 expression in SEMF by preventing the phosphorylation of I kappa B-alpha.