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Beta-defensins are small cationic peptides with antimicrobial properties that contribute to innate host defense. Unlike human beta-defensin-1 (hBD-1), which is produced constitutively, human beta-defensin-2 (hBD-2) is expressed after adequate stimulation by cytokines and/or bacterial endotoxins in epithelial tissue and mononuclear phagocytes but may be deficient in patients with Crohn's disease. To further elucidate the role of the intestinal epithelium in antimicrobial host defense, gene regulation of hBD-2 and the interaction with NF-kappaB were analyzed in a cell culture model. Human colonic epithelial cells (CaCo2) were stimulated by pro-inflammatory cytokines (IL-1beta, TNF-alpha, IF-gamma) to induce hBD-2 mRNA transcription. Interactions with NF-kappaB were analyzed using specific inhibitors (sulfasalazine, gliotoxine, dexamethasone) at different concentrations. Defensin mRNA expression was quantified by competitive RT-PCR and antibacterial capacity of supernatants was determined by an antimicrobial assay. HBD-2 mRNA transcription and antimicrobial activity of CaCo2 cells were induced by stimulation with pro-inflammatory cytokines. Induction was not inhibited by sulfasalazine or gliotoxine, whereas dexamethasone further enhanced both gene transcription and antimicrobial capacity. The lack of inhibition of induced hBD-2 expression by specific NF-kappaB antagonists suggests an additional pathway of activation, independent of NF-kappaB. The induction of hBD-2 expression in cytokine-stimulated CaCo2 cells by corticosteroids indicates further immunomodulatory ability of steroid hormones not yet understood. [ABSTRACT FROM AUTHOR]

Background/Aims:L-Glutamine (L-gln) is a conditionally essential amino acid which is consumed by certain tissues like the intestine in large amounts as energy source during critical illness. Apart from nutritive action, recent data suggest a link to heat-shock protein (hsp) induction. We investigated the effect of L-gln on hsp72 expression in the intestinal cell line Caco-2 under basal and heat-shock conditions and compared it with related amino acids. Methods: Total cellular protein was extracted and separated by SDS-PAGE. Immunoblots were performed with anti-hsp72 followed by chemiluminescence detection and densitometric scanning. Results: Following heat shock, hsp72 protein expression increased by 72 and 53% at 2 and 4 mmol/l L-gln, respectively, compared to heat shock alone (p < 0.05). Under basal conditions a limited increase occurred only at 8 mmol/l L-gln (p < 0.01). Levels remained unaffected when related amino acids including alanine, glutamate or glycine were supplemented under basal and heat-shock conditions. Similarly, the nonmetabolizable glutamine analogue DON or the toxic metabolite L-pyroglutamate did not induce hsp72. Conclusion: We conclude that the glutamine-mediated effect may be specifically attributed to the metabolic action of L-gln.Copyright © 2001 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Primary hyperoxaluria type 1 (PH1) is caused by deficiency of peroxisomal alanine-glyoxylate aminotransferase which is in humans exclusively expressed in liver cells. The disease is inherited as an autosomal recessive trait, and initial symptoms usually occur in early childhood. Up to the age of 25 years, 90% of the patients are symptomatic, and many patients develop end-stage renal failure. Pronounced medical care is necessary in PH1 patients to prevent generalized oxalosis with complications due to bone disease and peripheral gangrene. The rather short survival of patients on hemodialysis is caused by sudden arrhythmias and heart block. As no dialysis procedure is able to remove the daily produced oxalate, early transplantation is mandatory. Our 45-year-old patient is remarkable on the basis of the late manifestations of PH1. The diagnosis was delayed by unspecific symptoms of nephrolithiasis with recurrent pyelonephritis. Clinical course and diagnostic cornerstones of primary hyperoxaluria are outlined. The principles of conservative treatment and experiences with dialysis and transplantation are discussed.Copyright © 2001 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Octreotide is effective during 48 h in the treatment of acute variceal bleeding, probably by reducing variceal blood flow and pressure. Its basal and postprandial effects on splanchnic and systemic hemodynamics, and hormonal changes over this time interval have not yet been studied. Twenty-four patients with cirrhosis and portal hypertension were randomized to receive a liquid meal and either octreotide (Oct, 100 μg bolus intravenous, followed after 2 h by a continuous infusion of 25 μg/hr for 20 hr) or placebo (Plac) given at three consecutive days. Splanchnic (Doppler ultrasound) and systemic hemodynamics (noninvasive cardiac monitoring) were assessed on four consecutive days (one control day and three treatment days) during 2 hr. The postprandial increase in mean blood velocity of the superior mesenteric artery (SMA- Vmean, +44%), portal blood velocity (PV- Vmean, +44%) and total hepatic blood flow (HBF, +40%) observed in the placebo group during the control day was abolished during the first day of treatment (SMA-Vmean, +3%, P < 0.01; PV-Vmean, +6%, P < 0.05; HBF, −25%, P < 0.01) and still reduced after 48 hr in the octreotide group (SMA-Vmean, +28%, P < 0.05; PV-Vmean, +22%, P > 0.05; HBF, −8%, P < 0.05). The postprandial increase in cardiac index (CI, +10%) and decrease in systemic vascular resistance index (SVRI, −6%) were blunted after the initial injection of octreotide only (CI, −8%, P < 0.05; SVRI, +18%, P < 0.01). Endothelin-1-levels, which were increased at baseline (Plac 25 ± 17, Oct 16 ± 13 ng/liter, P > 0.05) decreased significantly after 48 hr of treatment with octreotide (Plac 27 ± 20, Oct 8 ± 4 ng/liter, P < 0.05). Octreotide is effective during 48 hr in the prevention of postprandial hyperemia in cirrhotics, even if its efficacy is decreasing over time. Moreover it may have positive effects on systemic vasodilation in cirrhotics. These findings suggest a potential role of this drug in the chronic treatment of portal hypertension. [ABSTRACT FROM AUTHOR]

Heat shock protein (Hsp) 70 is stress-inducible and exhibits both protective and antigenic properties. This study investigated the mucosal expression of the constitutive (Hsp70c) and inducible form (Hsp70i) as well as antibodies against human Hsp70 in inflammatory bowel disease and controls. Biopsies were assessed by immunoblot and immunofluorescence, resection specimens by immunohistochemistry, and mucosal antibody content by isoelectric focusing. Compared to controls, expression of Hsp70 was enhanced in ulcerative colitis (P<0.05), less so in Crohn's disease and infectious colitis. Strong epithelial staining was found for Hsp70c and Hsp70i in both diseases. Mucosal and submucosal mononuclear cells showed enhanced Hsp70c expression in Crohn's disease and to a lesser degree in ulcerative colitis. Antibodies of isotypes A or M were detected in nearly all patients and controls. The different pattern of Hsp70 expression in Crohn's disease compared to ulcerative colitis points to a distinct protective and immunological function, whereas a role in autoimmunity seems unlikely. [ABSTRACT FROM AUTHOR]

The effect of a low dose antacid treatment on mucosal prostaglandin metabolism was studied in 15 healthy volunteers. A daily dose of 46 mmol (= 138 mval) Al(OH)3 and 42 mmol (= 84 mval) Mg(OH)2 with a titrated in vitro neutralising capacity of 272 mval of H+ was given for three weeks. Total prostaglandin formation and the prostaglandin profile as well as the degradation of PGE2 were assayed by incubating homogenates of endoscopic biopsies from antral and duodenal mucosa with the precursor (14C)arachidonic acid. Total prostaglandin synthesis in antrum (623 (110) pmol/mg protein) and duodenum (432 (72) pmol/mg) was stimulated after three weeks administration of low dose antacids by 176% (p less than 0.05) and 154% (p less than 0.05), respectively. An untreated control group exhibited no significant changes. In contrast, the prostaglandin profile showed only a small increase of the prostacyclin metabolite 6-keto PGF1a (p less than 0.05) at the expense PGD2. PGE2 catabolism was unaffected. This enhanced activity of mucosal prostaglandin cyclooxygenase might represent one possible mechanism of action of a low dose antacid treatment. [ABSTRACT FROM PUBLISHER]

Heat shock proteins are induced by several stress factors and are potential antigens in autoimmune disorders. Expression of heat shock protein 90 (HSP 90) was investigated in patients with inflammatory bowel disease and normal controls. We combined western blot analysis with laser densitometry for quantitation. Localization of HSP 90 was investigated by immunohistochemistry. Western blots showed a significant mucosal expression of HSP 90, which was comparable in patients and controls. There was also no difference between normal and inflamed mucosa in inflammatory bowel disease. In immunohistochemical staining studies, HSP 90 was detected in epithelial cells, mononuclear cells, giant cells, nerve cells, and endothelial cells of small vessels. There was no difference in the intensity of staining or localization in patients with inflammatory bowel disease compared to controls. These findings render a potential protective or immunogenic function of HSP 90 in inflammatory bowel disease unlikely. [ABSTRACT FROM AUTHOR]

The article cites a study conducted by researcher H. Ogata and colleagues which examines the use of starlings in patients with refractory ulcerative colitis. The efficacy analysis included sixty patients of whom 15 were steroid resistant. High trough, low trough level and placebo groups achieved in 68, 38 and 10 percent improvement respectively. Seventy-three percent of patients achieved endoscopies healing.

A response by K. R. Herrlinger and E. F. Stange to a letter to the editor about their article "Infliximab As Rescue Medication for Patients With Severe Ulcerative / Indeterminate Colitis Refractory to Tacrolimus" in an earlier issue is presented.

. Gersemann M, Wehkamp J, Stange EF (Robert Bosch Hospital, Stuttgart; Dr. Margarete Fischer-Bosch Institute of Clinical Pharmacology, Stuttgart and University of Tübingen, Tübingen; Germany). Innate immune dysfunction in inflammatory bowel disease (Review). J Intern Med 2012; 271: 421-428. The pathogenetic mechanisms that cause the two types of inflammatory bowel disease (IBD), Crohn's disease (CD) and ulcerative colitis (UC), are still under investigation. Nevertheless, there is broad agreement that luminal microbes are of particular relevance in the development of these conditions. In recent years, increasing evidence has shown that defects in the innate immunity are at the centre of both types of IBD. The innate intestinal barrier is provided by the epithelium which secretes antimicrobial peptides (so-called defensins) that are retained in the mucus layer. In ileal CD, the alpha-defensins are lacking owing to several Paneth cell defects. In colonic CD, the expression of beta-defensins is inadequate. This may be related to downregulation of the transcription factor peroxisome proliferator-activated receptor-gamma and in some cohorts is associated with a reduced HBD2 gene copy number. In UC, the mucus layer, which protects the host from the enormous amounts of luminal microbes, is defective. This is accompanied by an insufficient differentiation from intestinal stem cells towards goblet cells. All these disturbances in the gut barrier shift the balance from epithelial defence towards bacterial offence. The current treatment for CD and UC is based on suppression of this secondary inflammatory process. In future, patients may benefit from new therapeutic approaches stimulating the protective innate immune system. [ABSTRACT FROM AUTHOR]

Antimicrobial peptides, in particular α-defensins expressed by Paneth cells, control microbiota composition and play a key role in intestinal barrier function and homeostasis. Dynamic conditions in the local microenvironment, such as pH and redox potential, significantly affect the antimicrobial spectrum. In contrast to oxidized peptides, some reduced defensins exhibit increased vulnerability to proteolytic degradation. In this report, we investigated the susceptibility of Paneth-cell-specific human α-defensin 5 (HD-5) and -6 (HD-6) to intestinal proteases using natural human duodenal fluid. We systematically assessed proteolytic degradation using liquid chromatography-mass spectrometry and identified several active defensin fragments capable of impacting bacterial growth of both commensal and pathogenic origins. Of note, incubation of mucus with HD-5 resulted in 255-8,000 new antimicrobial combinations. In contrast, HD-6 remained stable with consistent preserved nanonet formation. In vivo studies demonstrated proof of concept that a HD-5 fragment shifted microbiota composition (e.g., increases of Akkermansia sp.) without decreasing diversity. Our data support the concept that secretion of host peptides results in an environmentally dependent increase of antimicrobial defense by clustering in active peptide fragments. This complex clustering mechanism dramatically increases the host's ability to control pathogens and commensals. These findings broaden our understanding of host modulation of the microbiome as well as the complexity of human mucosal defense mechanisms, thus providing promising avenues to explore for drug development. [ABSTRACT FROM AUTHOR]

Background Steroid-refractory ulcerative colitis ( UC) remains a challenging condition warranting surgery upon failure of pharmacological treatment. Calcineurin inhibitors or infliximab are alternatives in this situation. Data on the efficacy and safety of tacrolimus in this setting are limited. Aim To study the short-term efficacy and safety of tacrolimus in moderate-to-severe steroid-refractory UC. The role of thiopurines in this situation and predictors of colectomy were evaluated. Methods In three centers, all charts from tacrolimus-treated patients with steroid-refractory UC were reviewed. Efficacy was assessed by colectomy-free survival and clinical remission at 3 months. Results We identified 130 patients with pancolitis in 75 (59%), left-sided disease in 35 (27%) and proctitis in 18 patients (14%) (disease localisation not obtainable in two patients). The median age was 40 (range: 18-81). Clinical activity according to the median Lichtiger score decreased from 13 (range: 4-17) at baseline to 3 (0-14) at week 12. Eighteen patients underwent colectomy within the first 3 months of treatment with tacrolimus (14%). Clinical remission was achieved in 94 patients (72%) in this period. Thiopurines given in parallel to tacrolimus tended to limit colectomy and significantly increased remission ( P = 0.002) in the short-term. No other predictors of colectomy or remission were identified. Side effects were noticed in 53% of patients and no severe events occurred. Conclusion This large survey confirms the efficacy and safety of tacrolimus in patients with steroid-refractory ulcerative colitis. [ABSTRACT FROM AUTHOR]

Aliment Pharmacol Ther 31, 1036–1041 Background The calcineurin inhibitor tacrolimus and the anti-TNF-antibody infliximab are established options in steroid-refractory ulcerative colitis (UC). Aim To evaluate the efficacy of infliximab-salvage therapy in patients with refractory UC failing to respond to tacrolimus. Methods Twenty-four patients were enrolled in this evaluation. Reasons for tacrolimus therapy were steroid-refractory disease in 19 patients and steroid-dependency in five patients. All patients receiving infliximab had tacrolimus-refractory active disease (Lichtiger score >10) and were treated with 5 mg/kg at weeks 0, 2 and 6 and every 8 weeks thereafter, if tolerated. Results Six of 24 patients (25%) achieved remission following infliximab infusion and four of 24 (17%) had an initial response only, but underwent proctocolectomy later because of loss of response (3) or development of a delayed hypersensitivity reaction (1). Fourteen patients (58%) completely failed to respond with 10 undergoing colectomy. Eight patients experienced side effects under infliximab, including two infectious complications (herpes zoster and herpes pneumonia). Conclusions Infliximab offers a therapeutic option as rescue therapy in about a quarter of patients with active UC after failing to respond to tacrolimus. This benefit has to be weighed against the risks of infectious complications. [ABSTRACT FROM AUTHOR]

Background Crohn’s Disease (CD), a chronic intestinal inflammation, is currently treated primarily by therapeutics which are directed against inflammatory responses. Recent findings though suggest a central role of the innate immune barrier in the pathophysiology. Important factors providing this barrier are antimicrobial peptides like the α- and β-defensins. Little is known about in vivo effects of common drugs on their expression. Aim To analyse the influence of corticosteroids, azathioprine and aminosalicylate treatment on ileal and colonic antimicrobial peptides in active CD and also assess the role of inflammation. Methods We measured the expression of antimicrobial peptides and pro-inflammatory cytokines in 75 patients with active CD. Results Ileal and colonic α- and β-defensins as well as LL37 remained unaffected by corticosteroids, azathioprine or aminosalicylate treatment. Additionally, we did not observe a negative coherency between Paneth cell α-defensins and any measured cytokines. HBD2 and LL37 unlike HBD1 levels were linked to inflammatory cytokines and increased in highly inflamed samples. Conclusions Current oral drug treatment seems to have no major effect on the expression of antimicrobial peptides. In contrast to HBD2 and LL37, ileal levels of HD5 and HD6 and colonic HBD1 level are independent of current inflammation. Innovative drugs should aim to strengthen protective innate immunity. [ABSTRACT FROM AUTHOR]

Recent evidence suggests that probiotic bacteria may stabilize gut barrier function via induction of anti-microbial peptides such as defensins. This study aimed to elucidate the induction mechanism of the human beta defensin-2 (hBD-2) gene by different probiotic lactobacillus strains. The expression of hBD-2 mRNA peaked at 6 h of incubation upon treatment of Caco-2 cells and increased with higher dosage of various probiotic bacteria. Deletion of nuclear factor (NF)-κB and activator protein-1 (AP-1) binding sites on the hBD-2 promoter resulted in a complete abrogation of promoter activation by probiotics. As revealed by the use of specific mitogen-activated protein kinase (MAPK) inhibitors the hBD-2 induction was dependent on the MAPK extracellular regulated kinase (ERK 1/2), p38 and c-Jun N-terminal kinase (JNK), although to varying degrees. Several Lactobacillus strains and VSL#3, a probiotic cocktail of four lactobacilli, three bifidum and one streptococcus species, induced the secretion of the hBD-2 peptide into the culture media as shown by enzyme-linked immunosorbent assay (ELISA). Thus, the present study suggests that lactobacilli and the VSL#3 bacterial mixture strengthen intestinal barrier functions through the up-regulation of hBD-2 via induction of proinflammatory pathways including NF-κB and AP-1 as well as MAPKs. [ABSTRACT FROM AUTHOR]

Background Increased biliary cholesterol secretion together with elevated cholesterol synthesis may predispose obese subjects to cholesterol gallstone formation. Aim To investigate whether processing of dietary cholesterol is altered in obesity, we enrolled eight lean and seven obese subjects in a double-blind crossover study. Methods Cholesterol consumption was 300 mg/day on low and 1300 mg/day on high cholesterol diet. After 3 weeks on either diet, hepatic bile was collected to determine biliary lipid secretion, and bile salt composition by high-performance liquid chromatography and cholesterol saturation index was calculated. Cholesterol synthesis was measured employing mass isotopomer distribution analysis. Bile acid synthesis via neutral and acidic pathway was assessed by serum levels of 7 α-hydroxy-4-cholesten-3-one and 27-hydroxycholesterol. Results Cholesterol synthesis was increased in obese compared with lean and feedback inhibited only in obese. On low cholesterol diet, cholesterol secretion was doubled in obese but bile acid composition and synthesis was similar between the two groups. After high cholesterol diet, cholesterol saturation index and bile secretion were unchanged. In contrast to obese, lean increased bile acid synthesis only via the acidic pathway. Conclusions Dietary cholesterol appears to preferentially induce bile acid synthesis via the acidic pathway in lean, whereas cholesterol synthesis was inhibited in obese. Thus, stable cholesterol saturation index may be achieved by different mechanisms. [ABSTRACT FROM AUTHOR]