Plecanatide, an Oral Guanylate Cyclase C Agonist Acting Locally in the Gastrointestinal Tract, Is Safe and Well-Tolerated in Single Doses

Purpose

Plecanatide, an analogue of uroguanylin, activates the guanylate cyclase C (GC-C) receptor found on the GI mucosal epithelial cells, leading to secretion of fluid, facilitating bowel movements. Plecanatide is being investigated as a potential treatment for constipating GI disorders. The aim of this investigation was to assess the safety, tolerability, pharmacokinetics (PK), and pharmacodynamics (PD) of single doses of plecanatide in healthy volunteers.

Methods

A total of 72 healthy volunteers at a single site were randomized in 9 cohorts to receive oral plecanatide or placebo from 0.1 to 48.6 mg. Plasma PK samples were collected pre-dose and post-dose. PD assessments included time to first stool, stool frequency, and stool consistency using the Bristol Stool Form Scale. All adverse events were documented.

Results

Plecanatide was safe and well-tolerated at all dose levels. A total of 17 of 71 subjects (23.9 %) reported 25 treatment-emergent adverse events (TEAEs) during the study. The number of TEAEs reported by subjects who received plecanatide or placebo was comparable (24.5 vs. 22.2 %, respectively). There were no dose-related increases in TEAEs or any SAEs reported. No measurable systemic absorption of oral plecanatide was observed at any of the oral doses studied, utilizing an assay sensitive down to 1 ng/mL.

Conclusions

Plecanatide, an oral GC-C agonist, acting locally within the GI tract without measurable systemic exposure, was safe and well-tolerated in single doses up to 48.6 mg. The study was not powered for statistical analyses, but trends in PD parameters supported continued clinical development.     

Oral treatment with plecanatide or dolcanatide attenuates visceral hypersensitivity via activation of guanylate cyclase-C in rat models

AIM To investigate the effects of plecanatide and dolcanatide on maintenance of paracellular permeability, integrity of tight junctions and on suppression of visceral hypersensitivity. METHODS Transport of fluorescein isothiocyanate(FITC)-dextran was measured to assess permeability across cell monolayers and rat colon tissues. Effects of plecanatide and dolcanatide on the integrity of tight junctions in Caco-2 and T84 monolayers and on the expression and localization of occludin and zonula occludens-1(ZO-1) were examined by immunofluorescence microscopy. Anti-nociceptive activity of these agonists was evaluated in trinitrobenzene sulfonic acid(TNBS)-induced inflammatory as well as in non-inflammatory partial restraint stress(PRS) rat models. Statistical significance between the treatment groups in the permeability studies were evaluated using unpaired t-tests.RESULTS Treatment of T84 and Caco-2 monolayers with lipopolysaccharide(LPS) rapidly increased permeability, which was effectively suppressed when monolayers were also treated with plecanatide or dolcanatide. Similarly, when T84 and Caco-2 monolayers were treated with LPS, cell surface localization of tight junction proteins occludin and ZO-1 was severely disrupted. When cell monolayers were treated with LPS in the presence of plecanatide or dolcanatide, occludin and ZO-1 were localized at the cell surface of adjoining cells, similar to that observed for vehicle treated cells. Treatment of cell monolayers with plecanatide or dolcanatide without LPS did not alter permeability, integrity of tight junctions and cell surface localization of either of the tight junction proteins. In rat visceral hypersensitivity models, both agonists suppressed the TNBS-induced increase in abdominal contractions in response to colorectal distension without affecting the colonic wall elasticity, and both agonists also reduced colonic hypersensitivity in the PRS model. CONCLUSION Our results suggest that activation of GC-C signaling might be involved in maintenance of barrier function, possibly through regulating normal localization of tight junction proteins. Consistent with these findings, plecanatide and dolcanatide showed potent antinociceptive activity in rat visceral hypersensitivity models. These results imply that activation of GC-C signaling may be an attractive therapeutic approach to treat functional constipation disorders and inflammatory gastrointestinal conditions.     

Oral nanotherapeutics: effect of redox nanoparticle on microflora in mice with dextran sodium sulfate-induced colitis

Background

Patients with ulcerative colitis (UC) exhibit overproduction of reactive oxygen species (ROS) and imbalance of colonic microflora. We previously developed a novel redox nanoparticle (RNP^O), which effectively scavenged ROS in the inflamed mucosa of mice with dextran sodium sulfate (DSS)-induced colitis after oral administration. The objective of this study was to examine whether the orally administered RNP^O changed the colonic microflora in healthy mice and those with colitis.

Methods

RNP^O was synthesized by self-assembly of an amphiphilic block copolymer that contains stable nitroxide radicals in hydrophobic side chain via ether linkage. Colitis was induced in mice by supplementing DSS in drinking water for 7 days, and RNP^O was orally administered daily during DSS treatment. The alterations of fecal microflora during treatment of DSS and RNP^O were investigated using microbiological assays.

Results

We investigated that RNP^O did not result in significant changes to the fecal microflora in healthy mice. Although total aerobic and anaerobic bacteria were not significantly different between experimental groups, a remarkable increase in commensal bacteria (Escherichia coli and Staphylococcus sp.) was observed in mice with DSS-induced colitis. Interestingly, orally administered RNP^O remarkably reduced the rate of increase of these commensal bacteria in mice with colitis.

Conclusions

On the basis of the obtained results, it was confirmed that the oral administration of RNP^O did not change any composition of bacteria in feces, which strongly suggests a protective effect of RNP^O on healthy environments in intestinal microflora. RNP^O may become an effective and safe medication for treatment of UC.     

Protective Effect of Lactulose on Dextran Sulfate Sodium-Induced Colonic Inflammation in Rats

Promising results have recently been obtained with pre- and probiotic therapy in ulcerative colitis (UC). The prebiotic potential of lactulose is well established, but it has not yet been investigated in experimental colitis models. The purpose of the study was to examine the effect of lactulose on an UC model induced by 3% dextran sulfate sodium (DSS) solution added to drinking water for 7 days in male Wistar rats. Lactulose (300-1000 mg/kg) or 5-aminosalicylic acid (5-ASA; 150 mg/kg) was administered orally twice daily for 6 days. Colonic ulceration area, colon length, body weight changes, diarrhea/bloody feces, colonic mucosal myeloperoxidase activity (MPO), thiobarbituric acid reactive substances (TBARS), and histology were examined. Treatment of animals with DSS for 7 days resulted in severe colonic lesions accompanied by diarrhea, bloody feces, a decrese in body weight, shortening of the colon length, and an increase in MPO activity as well as TBARS, compared to normal rats. Lactulose treatment ameliorated DSS-induced colitis in a dose-dependent manner, and at 1000 mg/kg all of the parameters examined, except TBARS, were shown to improve significantly as compared to controls. Daily administration of 5-ASA also significantly reduced the severity of colonic lesions following DSS treatment. These results demonstrated the protective effect of lactulose in this rat colitis model and suggested that the background of this lactulose effect may be due to alterations of colonic microflora.     

Rebamipide enema is effective for treatment of experimental dextran sulfate sodium induced colitis in rats

We investigated therapeutic efficacy of rebamipide using dextran sulfate sodium (DSS) induced colitis model in rats. Three percent DSS solution was given to rats for 9 days. After that, we evaluated the drug efficacy on colitis sustained with continuous drinking of 1% DSS. Twice-daily treatment with 0.3% or 1% rebamipide for 14 days significantly ameliorated the stool abnormality in the colitis model, preferentially suppressed hematochezia. The colonic mucosal lesion, determined by Alcian blue staining on day 24, was significantly reduced by rebamipide enema in a dose-dependent manner. Either rebamipide or 5-aminosalycilic acid (5-ASA) enema treated once daily significantly ameliorated colitis. The minimum effective dose of rebamipide was 0.3% in once-daily treatment, and that of 5-ASA was 10%. In a mechanistic study, the epithelial cell sheet formation of the T84 colon cancer cell was measured as an increase in generation of trans-epithelial electrical resistance in vitro. Rebamipide accelerated the increase, while 5-ASA conversely suppressed it. These results suggest that rebamipide enema is effective for treatment of experimental ulcerative colitis (UC).     

Geranylgeranylacetone protects mice from dextran sulfate sodium-induced colitis

Objective. Geranylgeranylacetone (GGA) has recently been reported to induce heat shock protein (HSP) 70, which has a protective function against inflammation. We investigated the therapeutic effects of oral administration of GGA on dextran sulfate sodium (DSS)-induced colitis in mice.Material and methods. BALB/c mice were given 3% DSS solution orally for 7?days to induce colitis. The disease activity of colitis was assessed clinically every day, and histology in the colon was evaluated at 7?days post-DSS. The levels of myeloperoxidase (MPO) activity, tumor necrosis factor (TNF)-α and interferon (IFN)-γ in the colon tissues were also examined. In addition, expression of HSPs 25, 40, 70 and 90 in the colon tissue was determined by Western blot analysis. Mice were orally administered GGA (50–500?mg/kg) when treatment of DSS started.Results. It was found that GGA significantly reduced the clinical severity of colitis and suppressed the levels of MPO activity, TNF-α and IFN-γ induced by DSS in the colon. On the other hand, GGA enhanced the expression of HSP70 in the colon of mice given DSS. HSP70-positive cells were identified in the epithelial cells of the colon from mice treated with GGA and DSS.Conclusions. Taken together, these results suggest that GGA is a new anti-inflammatory drug that could be useful in the treatment of colitis such as inflammatory bowel disease.     

Peroxisome proliferator-activated receptor gamma activation promotes intestinal barrier function by improving mucus and tight junctions in a mouse colitis model

Background and aimsDefects in mucus and intestinal epithelia can lead to intestinal inflammation in colitis. Reduced peroxisome proliferator-activated receptor gamma (PPAR_γ) in the mucosa may contribute to inflammation. However, the roles of PPAR_γ in the intestinal barrier remain poorly understood.MethodsChronic colitis was induced in C57BL/6 mice by administration of dextran sulfate sodium (DSS) for 27 days. Three days before DSS treatment, mice were treated with the PPAR_γ agonist rosiglitazone (Ro) orally at 20 mg kg⁻¹ day⁻¹.ResultsThe colitis based on disease activity index and colonic histopathology was significantly ameliorated in the DSS + Ro group. Additionally, mice in the DSS + Ro group had a thicker mucous layer than those in DSS + NS group, and muc2 mRNA expression was elevated significantly along with the mouse atonal homolog, SAM-pointed domain-containing Ets-like factor, and anterior gradient 2 genes. Moreover, tight junctions were up-regulated, whereas long myosin light chain kinase and phosphorylation of the myosin II light chain were lower in DSS + Ro mice. Similarly, after HT-29 and Caco-2 cells were treated by LPS or LPS + Ro, PPAR_γ activation by Ro could effectively improve the intestinal barrier, including intestinal mucus and tight junctions.ConclusionsOur results demonstrate that activated PPAR_γ could effectively promote intestinal mucus integrity by increasing the number of goblet cells, the glycosylation of mucins, and tight junctions via an MLCK-dependent mechanism.     

Guanylin-like peptides, guanylate cyclase and osmoregulation in the European eel (Anguilla anguilla)

Three guanylin-like peptides, guanylin, uroguanylin and renoguanylin and two guanylate cyclase type C (GC-C) receptor isoforms were cloned and sequenced from the European eel (Anguilla anguilla). All peptides and both receptors (GC-C1 and GC-C2) were predominantly expressed within the intestine and kidney of both sexually immature yellow, and sexually maturing, migratory silver eels. The derived amino acid sequences for the pre-prohormones and guanylate cyclase isoforms had structural features in common with sequences previously reported for guanylin-like peptides and guanylate cyclases from teleost fish and other species in general. The highest sequence homologies for the prohormones were found within the active, 15-16 amino acid C-terminal peptide domain, whereas the guanylate cyclase receptors exhibited highest homology throughout the transmembrane domain and intracellular region of the protein comprising the kinase homology, oligomerisation/coiled-coil and catalytic domains. In both yellow and silver eels, seawater (SW) acclimation induced sustained increases in the expression of uroguanylin and GC-C1 mRNAs within the intestine but no significant changes were found in the abundance of mRNAs for guanylin, renoguanylin or GC-C2. Likewise there were no significant changes in expression of any of the prohormone or receptor mRNAs within the renal kidney following transfer to SW. The results suggest that uroguanylin and GC-C1 are key components of a cGMP signalling system that may play an important role within intestinal enterocytes for the regulation of salt and water absorption in the SW-acclimated eel.     

Expression of GC-C, a receptor-guanylate cyclase, and its endogenous ligands uroguanylin and guanylin along the rostrocaudal axis of the intestine

Members of the receptor-guanylate cyclase (rGC) family possess an intracellular catalytic domain that is regulated by an extracellular receptor domain. GC-C, an intestinally expressed rGC, was initially cloned by homology as an orphan receptor. The search for its ligands has yielded three candidates: STa (a bacterial toxin that causes traveler's diarrhea) and the endogenous peptides uroguanylin and guanylin. Here, by performing Northern and Western blots, and by measuring [125I]STa binding and STa-dependent elevation of cGMP levels, we investigate whether the distribution of GC-C matches that of its endogenous ligands in the rat intestine. We establish that 1) uroguanylin is essentially restricted to small bowel; 2) guanylin is very low in proximal small bowel, increasing to prominent levels in distal small bowel and throughout colon; 3) GC-C messenger RNA and STa-binding sites are uniformly expressed throughout the intestine; and 4) GC-C-mediated cGMP synthesis peaks at the proximal and distal extremes of the intestine (duodenum and colon), but is nearly absent in the middle (ileum). These observations suggest that GC-C's activity may be posttranslationally regulated, demonstrate that the distribution of GC-C is appropriate to mediate the actions of both uroguanylin and guanylin, and help to refine current hypotheses about the physiological role(s) of these peptides.     

Cloning and mRNA expression of guanylin,uroguanylin, and guanylyl cyclase C in the Spinifex hopping mouse,Notomys alexis

Guanylin and uroguanylin are peptides that activate guanylyl cyclase C (GC-C) receptors in the intestine and kidney, which causes an increase in the excretion of salt and water. The Spinifex hopping mouse, Notomys alexis, is a desert rodent that can survive for extended periods without free access to water and it was hypothesised that to conserve water, the expression of guanylin, uroguanylin, and GC-C would be down-regulated to reduce the excretion of water in urine and faeces. Accordingly, this study examined the expression of guanylin, uroguanylin, and GC-C mRNA in Notomys under normal (access to water) and water-deprived conditions. Initially, guanylin and uroguanylin cDNAs encoding the full open reading frame were cloned and sequenced. A PCR analysis showed guanylin and uroguanylin mRNA expression in the small intestine, caecum, proximal and distal colon, heart, and kidney. In addition, a partial GC-C cDNA was obtained and GC-C mRNA expression was demonstrated in the proximal and distal colon, but not the kidney. Subsequently, a semi-quantitative PCR method showed that water deprivation in Notomys caused a significant increase in guanylin and uroguanylin mRNA expression in the distal colon, and in guanylin and GC-C mRNA expression in the proximal colon. No significant difference in guanylin and uroguanylin mRNA expression was observed in the kidney. The results of this study indicate that there is, in fact, an up-regulation of the colonic guanylin system in Notomys after 7 days of water deprivation.     

Rebamipide Enema is Effective for Treatment of Experimental Dextran Sulfate Sodium Induced Colitis in Rats

We investigated therapeutic efficacy of rebamipide using dextran sulfate sodium (DSS) induced colitis model in rats. Three percent DSS solution was given to rats for 9 days. After that, we evaluated the drug efficacy on colitis sustained with continuous drinking of 1% DSS. Twice-daily treatment with 0.3% or 1% rebamipide for 14 days significantly ameliorated the stool abnormality in the colitis model, preferentially suppressed hematochezia. The colonic mucosal lesion, determined by Alcian blue staining on day 24, was significantly reduced by rebamipide enema in a dose-dependent manner. Either rebamipide or 5-aminosalycilic acid (5-ASA) enema treated once daily significantly ameliorated colitis. The minimum effective dose of rebamipide was 0.3% in once-daily treatment, and that of 5-ASA was 10%. In a mechanistic study, the epithelial cell sheet formation of the T84 colon cancer cell was measured as an increase in generation of trans-epithelial electrical resistance in vitro. Rebamipide accelerated the increase, while 5-ASA conversely suppressed it. These results suggest that rebamipide enema is effective for treatment of experimental ulcerative colitis (UC).     

Increases in guanylin and uroguanylin in a mouse model of osmotic diarrhea are guanylate cyclase C-independent.

BACKGROUND & AIMS: Guanylin and uroguanylin are peptide hormones that are homologous to the diarrhea-causing Escherichia coli enterotoxins. These secretagogues are released from the intestinal epithelia into the intestinal lumen and systemic circulation and bind to the receptor guanylate cyclase C (GC-C). We hypothesized that a hypertonic diet would result in osmotic diarrhea and cause a compensatory down-regulation of guanylin/uroguanylin. METHODS: Gut-to-carcass weights were used to measure fluid accumulation in the intestine. Northern and/or Western analysis was used to determine the levels of guanylin, uroguanylin, and GC-C in mice with osmotic diarrhea. RESULTS: Wild-type mice fed a polyethylene glycol or lactose-based diet developed weight loss, diarrhea, and an increased gut-to-carcass ratio. Unexpectedly, 2 days on either diet resulted in increased guanylin/uroguanylin RNA and prohormone throughout the intestine, elevated uroguanylin RNA, and prohormone levels in the kidney and increased levels of circulating prouroguanylin. GC-C-deficient mice given the lactose diet reacted with higher gut-to-carcass ratios. Although they did not develop diarrhea, GC-C-sufficient and -deficient mice on the lactose diet responded with elevated levels of guanylin and uroguanylin RNA and protein. A polyethylene glycol drinking water solution resulted in diarrhea, higher gut-to-carcass ratios, and induction of guanylin and uroguanylin in both GC-C heterozygous and null animals. CONCLUSIONS: We conclude that this model of osmotic diarrhea results in a GC-C-independent increase in intestinal fluid accumulation, in levels of these peptide ligands in the epithelia of the intestine, and in prouroguanylin in the kidney and blood.     

Protective effect of intra-rectal administration of rebamipide on dextran sulfate sodium-induced rat colitis

BACKGROUND/AIM: Rebamipide, an anti-ulcer drug, has various actions including radical scavenging and mucus-stimulating as well as anti-inflammatory effects, and exhibits both mucosal protective and healing promoting actions in the stomach. In the present study, we examined the effect of rebamipide on an animal model of colitis induced by dextran sulfate sodium (DSS). METHODS: Experimental colitis was induced in rats by daily treatment with 3% DSS in drinking water for 7 days. Rebamipide (3-30 mg/kg), 5-aminosalicylic acid (5-ASA: 150 mg/kg) or metronidazole (10 and 30 mg/kg) was administered intra-rectally once daily for 6 days. The ulceration area, colon length, and mucosal myeloperoxidase (MPO) activity as well as thiobarbituric acid-reactive substance (TBARS) were measured on the 7th day after the onset of DSS treatment. The effects of rebamipide on the secretion of mucus in the colon was also examined. RESULTS: DSS treatment caused severe lesions in the colon, accompanied by an increase in MPO activity and TBARS as well as a decrease in body weight gain and colon length. Repeated administration of rebamipide dose-dependently suppressed the colon lesions and improved the pathological changes induced by DSS treatment. Rebamipide significantly increased the mucus contents in the colon. Both 5-ASA and metronidazole also reduced the severity of DSS-induced lesions. CONCLUSION: These results suggest that intra-rectal administration of rebamipide is effective against DSS-induced colitis. The protective effect of rebamipide may be attributable to both the radical scavenging action and the increase in the production of mucus in the colon, the latter presumably suppressing the process of intestinal bacterial infiltration.     

Effects of Proteoglycan on Dextran Sulfate Sodium-Induced Experimental Colitis in Rats

Proteoglycans (PG) are macromolecules composed of glycosaminoglycan chains covalently attached to a protein core. In this study, we examined the effects of PG on dextran sulfate sodium (DSS)-induced experimental colitis in rats. First, to examine whether PG may ameliorate acute established DSS colitis, PG was administered orally for 5 days to the model animals. We evaluated the effects of PG on the basis of clinical symptoms, hematological analysis, macroscopic observation, and microscopic examination. We then examined whether PG administered orally to rats was detectable in their colonic lumen. After administration of PG, the colonic contents were collected, and the molecular weight of PG in the sample was analyzed by gel filtration high-performance liquid chromatography. Furthermore, we examined whether orally administered PG affected the concentrations of short-chain fatty acids (SCFAs) in the colonic feces. Orally administered PG ameliorated the clinical symptoms of bloody stools and diarrhea, and attenuated the increase in the white blood cell count in rats with established DSS colitis. Histologically, orally administered PG reduced the degree of mucosal erosion and inflammatory cell infiltration into the erosive area induced by DSS. Orally administered PG was detected in rat colon, although its molecular weight was slightly decreased. Orally administered PG significantly increased the concentration of total SCFAs and n-butyrate in rat colonic feces. This is the first study to indicate that exogenous PG ameliorates experimental colitis, suggesting the potential usefulness of PG for clinical treatment of colitis.     

Uroguanylin and guanylate cyclase C in the human pancreas: expression and mutuality of ligand/receptor localization as indicators of intercellular paracrine signaling pathways.

The intestinal peptide hormone uroguanylin regulates electrolyte/fluid transport in the gastrointestinal epithelium by binding to its receptor, guanylate cyclase C (GC-C), and thus specifically coupling to activation of cystic fibrosis transmembrane conductance regulator (CFTR). Since CFTR is crucially involved in pancreatic electrolyte secretion, we investigated the human pancreas for expression and cell-specific localization of uroguanylin and guanylate cyclase C as potential regulatory components of pancreatic electrolyte secretion. RT-PCR analyses with specific primers revealed that uroguanylin and GC-C are expressed in the human pancreas (and in the duodenum, used as positive control); at the translational level, western blotting analyses with peptide- and region-specific antibodies identified the presence of 12.5 kDa uroguanylin and 130 kDa GC-C in both human pancreatic and intestinal extracts. At the cellular level, uroguanylin and GC-C immunoreactivities were absent from the islets of Langerhans but were exclusively confined to the exocrine parenchyma. Hence, uroguanylin was localized to the centroacinar cells typical of the pancreas, and also to epithelial cells of the intercalated, intralobular and interlobular ducts where the peptide was primarily concentrated adluminally to the apical portion of the respective cells. Coincidently, correlative studies localized the GC-C receptor to the epithelial cells of the ductal network, where it was confined exclusively to the apical cell membrane that evidently represents the functionally relevant target membrane domain for the regulatory peptide. In view of the fact that CFTR is highly expressed in pancreatic ductal cells where uroguanylin and its receptor are also localized, we assume that uroguanylin, an intrinsic pancreatic peptide, is involved in the regulation of electrolyte/water secretion in the ductal system via GC-C and CFTR. The particular cellular expression of uroguanylin in duct cells and the localization of GC-C to the duct cell apical membrane domain predict a novel route of intercellular signaling and luminal activation of GC-C via the pancreatic juice.     

Kefir treatment ameliorates dextran sulfate sodium-induced colitis in rats

AIM: To investigate the preventive effect of kefir on colitis induced with dextran sulfate sodium(DSS) in rats.METHODS: Twenty-four male Wistar-albino rats were randomized into four groups: normal control,kefircontrol,colitis,and kefir-colitis groups. Rats in the normal and kefir-control groups were administered tap water as drinking water for 14 d. Rats in the colitis and kefir-colitis groups were administered a 3% DSS solution as drinking water for 8-14 d to induce colitis. Rats in the kefir-control and kefir-colitis groups were administered 5 m L kefir once a day for 14 d while rats in the normal control and colitis group were administered an identical volume of the placebo(skim milk) using an orogastric feeding tube. Clinical colitis was evaluated with reference to the disease activity index(DAI),based on daily weight loss,stool consistency,and presence of bleeding in feces. Rats were sacrificed on the 15 th day,blood specimens were collected,and colon tissues were rapidly removed. Levels of myeloperoxidase(MPO),tumor necrosisfactor(TNF)-α,interleukin(IL)-10,malondialdehyde,and inducible nitric oxide synthase(i NOS) were measured in colon tissue.RESULTS: The DAI was lower in the kefir-colitis group than in the colitis group(on the 3rd and 5th days of colitis induction; P 0.01). The DAI was also significantly higher in the colitis group between days 2 and 6 of colitis induction when compared to the normal control and kefir-control groups. The DAI was statistically higher only on the 6th day in the kefircolitis group when compared to that in the normal control groups. Increased colon weight and decreased colon length were observed in colitis-induced rats. Mean colon length in the colitis group was significantly shorter than that of the kefir-control group. Kefir treatment significantly decreased histologic colitis scores(P 0.05). MPO activity in the colitis group was significantly higher than in the kefir-control group(P 0.05). Kefir treatment significantly reduced the DSS colitis-induced TNF-α increase(P 0.01). No statistically significant differences were observed among groups for IL-10 and MDA levels. Colon tissue i NOS levels in the colitis group were significantly higher than those in the control and kefir-colitis groups(P 0.05).CONCLUSION: Kefir reduces the clinical DAI and histologic colitis scores in a DSS-induced colitis model,possibly via reduction of MPO,TNF-α,and i NOS levels.     

Geranylgeranylacetone protects mice from dextran sulfate sodium-induced colitis

OBJECTIVE: Geranylgeranylacetone (GGA) has recently been reported to induce heat shock protein (HSP) 70, which has a protective function against inflammation. We investigated the therapeutic effects of oral administration of GGA on dextran sulfate sodium (DSS)-induced colitis in mice. MATERIALS AND METHODS: BALB/c mice were given 3% DSS solution orally for 7 days to induce colitis. The disease activity of colitis was assessed clinically every day, and histology in the colon was evaluated at 7 days post-DSS. The levels of myeloperoxidase (MPO) activity, tumor necrosis factor (TNF)-alpha and interferon (IFN)-gamma in the colon tissues were also examined. In addition, expression of HSPs 25, 40, 70 and 90 in the colon tissue was determined by Western blot analysis. Mice were orally administered GGA (50-500 mg/kg) when treatment of DSS started. RESULTS: It was found that GGA significantly reduced the clinical severity of colitis and suppressed the levels of MPO activity, TNF-alpha and IFN-gamma induced by DSS in the colon. On the other hand, GGA enhanced the expression of HSP70 in the colon of mice given DSS. CONCLUSIONS: Taken together, these results suggest that GGA is a new anti-inflammatory drug that could be useful in the treatment of colitis such as inflammatory bowel disease.