Mechanisms of PTHrP-induced inhibition of smooth muscle contractility in the guinea pig gastric antrum.

BACKGROUND: Parathyroid hormone-related protein (PTHrP) that causes hypercalcemia of malignancy appears to function as an endogenous smooth muscle relaxant. For example, PTHrP released upon bladder wall distension relaxes detrusor smooth muscle to accommodate urine. Here, we explored mechanisms underlying PTHrP-induced suppression of the smooth muscle contractility in the gastric antrum that also undergoes a passive distension. METHODS: Effects of PTHrP on phasic contractions and electrical slow waves in the antral smooth muscle of the guinea pig stomach were studied using isometric tension and intracellular microelectrode recordings, respectively. Fluorescent immunohistochemistry was also carried out to identify the distribution of PTH/PTHrP receptors. KEY RESULTS: Parathyroid hormone-related protein (1-100 nM) reduced the amplitude of phasic contractions and the basal tension. Nω -nitro-l-arginine (L-NA, 100 µM), a nitric oxide (NO) synthase inhibitor, or 1H-[1,2,4]oxadiazolo-[4, 3-a]quinoxalin-1-one (ODQ, 10 µM), a guanylate cyclase inhibitor, diminished the PTHrP (10 nM)-induced reduction in the amplitude of phasic contractions. SQ22536 (300 µM), an adenylate cyclase inhibitor, attenuated the PTHrP-induced reduction in basal tension. The combination of ODQ (10 µM) and SQ22536 (300 µM) inhibited the PTHrP-induced reductions in both phasic contractions and basal tension. PTHrP (100 nM) had no inhibitory effect on the electrical slow waves in the antral smooth muscle. PTH/PTHrP receptors were expressed in cell bodies of PGP9.5-positive neurons in the myenteric plexus. CONCLUSIONS & INFERENCES: Parathyroid hormone-related protein exerts its inhibitory actions on the antral smooth muscle via both nitric oxide-cyclic guanosine monophosphate (NO-cGMP) and cyclic adenosine monophosphate (AMP) pathways. Thus, PTHrP may act as an endogenous relaxant of the gastric antrum employing the two complementary signaling pathways to ensure the adaptive relaxation of stomach.

A Phase I Randomized Study of a Specifically Engineered, pH-Sensitive PCSK9 Inhibitor RN317 (PF-05335810) in Hypercholesterolemic Subjects on Statin Therapy.

This phase I study assessed the safety, tolerability, pharmacokinetics, and pharmacodynamics of RN317 (PF-05335810), a specifically engineered, pH-sensitive, humanized proprotein convertase subtilisin kexin type 9 (PCSK9) monoclonal antibody, in hypercholesterolemic subjects (low-density lipoprotein cholesterol (LDL-C) ≥ 80 mg/dl) 18-70 years old receiving statin therapy. Subjects were randomized to: single-dose placebo, RN317 (subcutaneous (s.c.) 0.3, 1, 3, 6, or intravenous (i.v.) 1, 3, 6 mg/kg), or bococizumab (s.c. 1, 3, or i.v. 1 mg/kg); or multiple-dose RN317 (s.c. 300 mg every 28 days; three doses). Of 133 subjects randomized, 127 completed the study. RN317 demonstrated a longer half-life, greater exposure, and increased bioavailability vs. bococizumab. RN317 was well tolerated, with no subjects discontinuing because of treatment-related adverse events. RN317 lowered LDL-C by up to 52.5% (day 15) following a single s.c. dose of 3.0 mg/kg vs. a maximum of 70% with single-dose bococizumab s.c. 3.0 mg/kg. Multiple dosing of RN317 produced LDL-C reductions of ∼50%, sustained over an 85-day dosing interval.

Immunological potential of cytotoxic T lymphocyte antigen 4 immunoglobulin in murine autoimmune cholangitis.

Cytotoxic T lymphocyte antigen 4 (CTLA-4) immunoglobulin (Ig) is an important regulator of T cell activation and a fusion protein directed at CD80 and CD86; it blocks co-stimulatory signalling and T cell activation. We have taken advantage of a murine model of human primary biliary cirrhosis (PBC), mice expressing a transforming growth factor (TGF)-ß receptor II dominant negative (dnTGF-ßRII) transgene to address the potential therapeutic efficacy of CTLA-4 Ig. To mimic patients with PBC at different stages or duration of disease, we treated mice with either CTLA-4 Ig or control IgG three times weekly from 3 to 12 or 24 weeks of age, or from 12 to 24 weeks of age. CTLA-4 Ig treatment from 3 weeks of age significantly reduced liver inflammation to 12 weeks of age. Treatment initiated at 12 weeks of age also ameliorated the autoimmune cholangitis at 24 weeks of age. However, in mice treated at 3 weeks of age, suppression of liver inflammation was not sustained and colitis was aggravated when treatment was extended to 24 weeks of age. Our data indicate that, in dnTGF-ßRII mice, CTLA-4 Ig treatment has short-term beneficial effects on autoimmune cholangitis, but the effect varies according to duration of treatment and the time in which therapy was initiated. Further dissection of the events that lead to the reduction in therapeutic effectiveness of CTLA-4 Ig will be critical to determining whether such efforts can be applied to human PBC.

eNOS plays an important role in the regulation of colonic inflammation: a novel therapeutic target and a predictive marker for the prognosis of ulcerative colitis.

BACKGROUND: We reported that deficiency of the eNOS protein exacerbates colitis induced by dextran sodium sulfate (DSS-induced colitis). However, the role of eNOS in colitis remains controversial. Therefore, we studied how over-expression of eNOS affected this inflammatory condition, using vascular endothelial cells and mice as in vitro and in vivo models, respectively. Furthermore, we investigated the influence of a polymorphism in the eNOS gene on the clinical features of ulcerative colitis (UC). METHODS: We examined the effect of eNOS overexpression on the expression of adhesion molecules in the endothelium and assessed the degree of DSS-induced colitis in eNOS transgenic (eNOS-Tg) mice. We also investigated the relationship between a polymorphism in the eNOS gene and clinical features of patients with UC. RESULTS: The expression of adhesion molecules, under inflammatory conditions, was attenuated in eNOS gene-transfected vascular endothelial cells, as measured by western blot analysis. Symptoms of DSS-induced colitis were likewise attenuated in eNOS-Tg mice, which exhibited lower weight loss, mortality, histological damage (by inflammation score and crypt damage score), and colonic myeloperoxidase activity, tumor necrosis factor-α expression, and MAdCAM-1 expression than in wild-type mice. Furthermore, there was a significant relationship between intractable cases of UC and a polymorphism in the eNOS gene promoter (c.-786 T > C) that decreases eNOS expression. CONCLUSION: The eNOS gene plays an important role in the regulation of colonic inflammation. The level of eNOS expression may be a predictive marker for prognosis of UC, and eNOS expression may be a novel therapeutic target.

Successful immunotherapy of autoimmune cholangitis by adoptive transfer of forkhead box protein 3(+) regulatory T cells.

Treatment of primary biliary cirrhosis (PBC) has lagged behind that of other autoimmune diseases. In this study we have addressed the potential utility of immunotherapy using regulatory T cells (Treg ) to treat murine autoimmune cholangitis. In particular, we have taken advantage of our ability to produce portal inflammation and bile duct cell loss by transfer of CD8(+) T cells from the dominant negative form of transforming growth factor beta receptor type II (dnTGF-ßRII) mice to recombination-activating gene (Rag)1(-/-) recipients. We then used this robust established adoptive transfer system and co-transferred CD8(+) T cells from dnTGF-ßRII mice with either C57BL/6 or dnTGF-ßRII forkhead box protein 3 (FoxP3(+) ) T cells. Recipient mice were monitored for histology, including portal inflammation and intralobular biliary cell damage, and also included a study of the phenotypical changes in recipient lymphoid populations and local and systemic cytokine production. Importantly, we report herein that adoptive transfer of Treg from C57BL/6 but not dnTGF-ßRII mice significantly reduced the pathology of autoimmune cholangitis, including decreased portal inflammation and bile duct damage as well as down-regulation of the secondary inflammatory response. Further, to define the mechanism of action that explains the differential ability of C57BL/6 Treg versus dnTGF-ßRII Treg on the ability to down-regulate autoimmune cholangitis, we noted significant differential expression of glycoprotein A repetitions predominant (GARP), CD73, CD101 and CD103 and a functionally significant increase in interleukin (IL)-10 in Treg from C57BL/6 compared to dnTGF-ßRII mice. Our data reflect the therapeutic potential of wild-type CD4(+) FoxP3(+) Treg in reducing the excessive T cell responses of autoimmune cholangitis, which has significance for the potential immunotherapy of PBC.

ITPA genetic variants influence efficacy of PEG-IFN/RBV therapy in older patients infected with HCV genotype 1 and favourable IL28B type.

Inosine triphosphatase (ITPA) genetic variants are strongly associated with ribavirin (RBV)-induced anaemia during pegylated interferon (PEG-IFN) plus RBV therapy. However, the treatment efficacy of ITPA genetic variants has not been fully explored. We enrolled 309 individuals infected with hepatitis C virus genotype 1, who were treated with PEG-IFN plus RBV for 48 weeks. The ITPA SNP: rs1127354 and IL28B SNP: rs8099917 were genotyped. We examined the risk factors for severe anaemia up to week 12 after the start of treatment and treatment efficacy. The incidence of severe anaemia, ≥ 3 g/dL reduction or <10 g/dL of haemoglobin (Hb) up to week 12, was more frequent in patients with CC at rs1127354 [65% (145/224), 33% (73/224)] than in those with CA/AA [25% (21/85), 6% (8/85)] (P < 0.0001). ITPA genotype, pretreatment Hb level and age were independent predictive factors for severe anaemia: Hb < 10 g/dL. In IL28B favourable type, the sustained virologic response rate was higher in ≥ 60-year-old patients with CA/AA than in those with CC [71% (22/31) vs 40% (26/65), P = 0.005], although there was no significant difference in treatment efficacy according to ITPA genetic variants in the <60-year-old patients. The proportion of patients administered ≥ 80% of the dosage of RBV was significantly higher in the patients with CA/AA than in those with CC (P = 0.025), resulting in a lower relapse rate. In conclusion, ITPA genetic variants were associated with severe RBV-induced anaemia and could influence the efficacy of PEG-IFN plus RBV treatment among elderly patients with IL28B favourable type.

Randomized clinical trial: rikkunshito in the treatment of functional dyspepsia--a multicenter, double-blind, randomized, placebo-controlled study.

BACKGROUND: Rikkunshito, a standardized Japanese herbal medicine, is thought to accelerate gastric emptying and relieve dyspepsia, although no large-scale, randomized, placebo-controlled trials of rikkunshito have been conducted. This study aimed to determine the efficacy and safety of rikkunshito for treating functional dyspepsia (FD). METHODS: FD patients received 2.5 g rikkunshito or placebo three times a day for 8 weeks in this multicenter, randomized, placebo-controlled, parallel-group trial. The primary end point was the proportion of responders at 8 weeks after starting test drug, determined by global patient assessment (GPA). The improvement in four major dyspepsia symptoms severity scale was also evaluated. In addition, plasma ghrelin levels were investigated before and after treatment. KEY RESULTS: Two hundred forty-seven patients were randomly assigned. In the eighth week, the rikkunshito group had more GPA responders (33.6%) than the placebo (23.8%), although this did not reach statistical significance (p = 0.09). Epigastric pain was significantly improved (p = 0.04) and postprandial fullness tended to improve (p = 0.06) in the rikkunshito group at week 8. Rikkunshito was relatively more effective among Helicobacter pylori-infected participants (rikkunshito: 40.0% vs placebo: 20.5%, p = 0.07), and seemed less effective among H. pylori-uninfected participants (rikkunshito: 29.3% vs placebo: 25.6%, p = 0.72). Among H. pylori-positive individuals, acyl ghrelin levels were improved just in rikkunshito group. There were no severe adverse events in both groups. CONCLUSIONS & INFERENCES: Administration of rikkunshito for 8 weeks reduced dyspepsia, particularly symptoms of epigastric pain and postprandial fullness. (UMIN Clinical Trials Registry, Number UMIN000003954).

Anti-CD40 ligand monoclonal antibody delays the progression of murine autoimmune cholangitis.

While there have been significant advances in our understanding of the autoimmune responses and the molecular nature of the target autoantigens in primary biliary cirrhosis (PBC), unfortunately these data have yet to be translated into new therapeutic agents. We have taken advantage of a unique murine model of autoimmune cholangitis in which mice expressing a dominant negative form of transforming growth factor ß receptor II (dnTGFßRII), under the control of the CD4 promoter, develop an intense autoimmune cholangitis associated with serological features similar to human PBC. CD40-CD40 ligand (CD40L) is a major receptor-ligand pair that provides key signals between cells of the adaptive immune system, prompting us to determine the therapeutic potential of treating autoimmune cholangitis with anti-CD40L antibody (anti-CD40L; MR-1). Four-week-old dnTGFßRII mice were injected intraperitoneally with either anti-CD40L or control immunoglobulin (Ig)G at days 0, 2, 4 and 7 and then weekly until 12 or 24 weeks of age and monitored for the progress of serological and histological features of PBC, including rigorous definition of liver cellular infiltrates and cytokine production. Administration of anti-CD40L reduced liver inflammation significantly to 12 weeks of age. In addition, anti-CD40L initially lowered the levels of anti-mitochondrial autoantibodies (AMA), but these reductions were not sustained. These data indicate that anti-CD40L delays autoimmune cholangitis, but the effect wanes over time. Further dissection of the mechanisms involved, and defining the events that lead to the reduction in therapeutic effectiveness will be critical to determining whether such efforts can be applied to PBC.

Preoperative drainage using a transanal tube enables elective laparoscopic colectomy for obstructive distal colorectal cancer.

BACKGROUND AND STUDY AIMS: Acute colorectal obstruction (ACO) often accompanies colorectal cancer (CRC) and requires urgent treatment, but achieving elective laparoscopy-assisted colectomy (LAC) is difficult in this setting. The aim of the current study was to assess the clinical outcomes of a transanal tube (Dennis colorectal tube [DCT]) for CRC with ACO, focusing in particular on the impact of the DCT on subsequent elective LAC. PATIENTS AND METHODS: Among 1142 patients who underwent surgery for CRC between January 2007 and December 2011, 92 patients with ACO were identified retrospectively. Of these 92 patients, the DCT procedure was performed in 66 patients who fulfilled the indications for DCT, and these patients were included in the study. RESULTS: All 66 patients presented with complete obstruction. Technical and clinical success rates for DCT were 93.9 % and 86.4 %, respectively. Perforation after DCT occurred in 4.5 % and the mortality rate was 1.5 %. The rate of LAC was 48.5 %, and the rate of primary stoma was 13.6 %. For curative stage II/III CRC with ACO, DCT resulted in a primary stoma rate of 13.6 %, a one-stage surgery rate of 90.9 %, a LAC rate of 50.0 %, and a 3-year survival rate of 73.1 %. For stage II/III CRC cases with clinical success by DCT, the one-stage surgery rate was 97.4 % and the LAC rate was 56.4 %. CONCLUSIONS: DCT achieved a high rate of clinical success and enabled safe one-stage surgery and LAC for CRC with ACO. DCT followed by LAC is proposed as a promising non-invasive strategy for CRC with ACO.

Effects of transglucosidase on diabetes, cardiovascular risk factors and hepatic biomarkers in patients with type 2 diabetes: a 12-week, randomized, double-blind, placebo-controlled trial.

In this 12-week, randomized, double-blind, placebo-controlled trial, the efficacy and safety of transglucosidase (TGD) were compared with placebo in patients with type 2 diabetes mellitus (T2DM). At 12 weeks, TGD 300 mg/day and TGD 900 mg/day significantly reduced HbA1c (0.18 and 0.21%) and insulin concentration (19.4 and 25.0 pmol/l), respectively, vs. placebo. TGD 300 mg/day and TGD 900 mg/day also significantly reduced low-density lipoprotein cholesterol (0.22 and 0.17 mmol/l, respectively). TGD 900 mg/day significantly reduced triglyceride by 0.24 mmol/l and diastolic blood pressure by 8 mmHg. Placebo was associated with a significant increase from baseline in body mass index, alanine aminotransferase and aspartate aminotransferase (0.17 kg/m(2) , 3 and 2 U/l, respectively), whereas TGD was not. TGD 300 mg/day significantly increased high-molecular-weight adiponectin by 0.6 µg/ml. Adverse events did not differ significantly between the groups. TGD resulted in lowering of HbA1c and blood insulin level and improvements in metabolic and cardiovascular risk factors in T2DM.

Acid inhibits TRPV4-mediated Ca²âº influx in mouse esophageal epithelial cells.

BACKGROUND: The transient receptor potential vanilloid 4 (TRPV4), a thermo-sensitive stretch-activated cation channel, is expressed in the skin stratified squamous epithelium, contributing to the acquisition of barrier function. Similarly, functional TRPV4 may be located in the stratified squamous epithelial lining of the esophagus, being involved in the pathogenesis of gastroesophageal reflux disease (GERD). Here we investigated the expression of TRPV4 in the mouse esophageal epithelium. METHODS: TRPV4 expression at the mRNA and protein levels was examined by reverse transcription-polymerase chain reaction (RT-PCR), in situ hybridization, and immunohistochemistry. A calcium imaging technique and ATP assay were used to evaluate the functionality of TRPV4 in freshly isolated esophageal epithelial cells. KEY RESULTS: Transcripts and proteins encoding TRPV4 were colocalized in the basal and intermediate layers of the esophageal epithelium. Both 4α-phorbol 12,13- didecanoate (4α-PDD), a selective agonist for TRPV4, and hypo-osmolar solution (160 mOsm) elevated the intracellular calcium concentration ([Ca(2+) ](i) ) in a subset of the isolated cells (70%). These [Ca(2+) ](i) increases were potently inhibited by ruthenium red (RuR), a TRPV4 channel antagonist, and were suppressed by extracellular protons (pH 5.0). Finally, application of 4α-PDD evoked ATP release in primary esophageal epithelial cells. CONCLUSIONS & INFERENCES: Acid-sensitive TRPV4 channels were mainly expressed in the esophageal epithelial cells of the basal and intermediate layers. Direct exposure of TRPV4-expressing cells to gastric acid, as would occur in cases of GERD, could influence their cellular functions, possibly aggravating the disease state.

Elevated serum uric acid predicts impaired fasting glucose and type 2 diabetes only among Japanese women undergoing health checkups.

AIM: This study assessed whether or not elevated serum uric acid can predict impaired fasting glucose (IFG) and type 2 diabetes mellitus (T2DM) in Japanese people undergoing health checkups. METHODS: Altogether, 7114 male and 5529 female participants in both 2000 and 2005 were targeted for the study. After excluding those with IFG and T2DM, multiple logistic-regression analyses of 6408 men and 5309 women-average ages 48.4±10.2 and 50.0±9.1 years, respectively-were performed to identify independent risk factors for newly diagnosed IFG and T2DM in 2005, after adjusting for age, parental history of diabetes, body mass index (BMI), elevated blood pressure or hypertension, fatty liver, hypertriglyceridaemia, alcohol consumption and smoking status. RESULTS: Prevalence rates for IFG and T2DM, and values for BMI, systolic and diastolic blood pressure, fasting blood glucose and triglycerides, showed significantly increasing trends in relation to serum uric acid quartiles in both genders. IFG and T2DM were newly diagnosed in 8.1% of men and 4.0% of women in 2005. Using multivariate models, the highest quartile of serum uric acid and increases in serum uric acid were independent risk factors, but only in women. Serum uric acid was not a risk factor in men when categorized by the cut-off values of 4.8 mg/dL, the limit for the highest quartile in women, and of 7.0 mg/dL. CONCLUSION: Elevated serum uric acid predicted IFG and T2DM only in Japanese women undergoing regular health checkups.

Analysis of VH gene rearrangement and somatic hypermutation in Sjogren's syndrome and IgG4-related sclerosing sialadenitis.

IgG4-related sclerosing sialadenitis is currently considered as an autoimmune disease distinct from Sjogren's syndrome (SS) and responds extremely well to steroid therapy. To further elucidate the characteristics of IgG4-related sclerosing sialadenitis, we analysed VH fragments of IgH genes and their somatic hypermutation in SS (n = 3) and IgG4-related sclerosing sialadenitis (n = 3), using sialolithiasis (n = 3) as a non-autoimmune control. DNA was extracted from the affected inflammatory lesions. After PCR amplification of rearranged IgH genes, at least 50 clones per case (more than 500 clones in total) were sequenced for VH fragments. Monoclonal IgH rearrangement was not detected in any cases examined. When compared with sialolithiasis, there was no VH family or VH fragment specific to SS or IgG4-related sclerosing sialadenitis. However, rates of unmutated VH fragments in SS (30%) and IgG4-related sclerosing sialadenitis (39%) were higher than that in sialolithiasis (14%) with statistical significance (P = 0.0005 and P < 0.0001, respectively). This finding suggests that some autoantibodies encoded by germline or less mutated VH genes may fail to be eliminated and could play a role in the development of SS and IgG4-related sclerosing sialadenitis.

The effectiveness of packed therapy with three drugs in Helicobacter pylori eradication in Japan.

Primary Helicobacter pylori eradication rate using triple therapy (a proton pump inhibitor [PPI] + amoxicillin [AMPC] + clarithromycin [CAM], over 7 days) is showing a declining trend. In this study we report recent eradication rates and have evaluated the usefulness of a pack preparation of three drugs. H. pylori eradication rate was 85.1% (57/67) in 2004 but then fell to 75.2% (79/105) in 2005, 70.1% (68/97) in 2006 and 69.9% (58/83) in 2007. With the introduction of packs (lansoprazole [LPZ] 60 mg, AMPC 1500 mg, CAM 400 mg) the eradication rate recovered to 78.0% (110/141) in 2008. A comparative study in 2008 delineated that the eradication rate in the pack group (88.4%, 38/43) was significantly higher than that of the conventional group (73.5%, 72/98). These results suggest that packs of eradication medicine are useful in increasing eradication success.

Clinical features of interstitial lung disease induced by standard chemotherapy (FOLFOX or FOLFIRI) for colorectal cancer.

BACKGROUND: Chemotherapy-induced interstitial lung disease (ILD) in colorectal cancer (CRC) patients is rarely reported, but its clinical features remain to be clarified. PATIENTS AND METHODS: Using a computerized database, we retrospectively identified patients who developed ILD from 734 patients with CRC treated with infusional 5-fluorouracil, leucovorin and oxaliplatin (FOLFOX) or infusional 5-fluorouracil, leucovorin and irinotecan (FOLFIRI) from April 2005 to December 2008 at the National Cancer Center Hospital East. RESULTS: Of 734 patients, 11 patients developed ILD (1.5%) and 4 of those patients died (0.54%). Of the 11 patients, 10 showed pulmonary shadows other than lung metastases before chemotherapy. ILD developed during FOLFOX in six patients, at 137 days after completion of FOLFOX in one patient, during oxaliplatin interruption of FOLFOX in one patient and during FOLFIRI in the remaining three patients. FOLFOX had been administered at some point for all ILD patients, with a median of 10 cycles (range 2-17 cycles) and a median dose of administered oxaliplatin of 850 mg/m(2) (range 170-1445 mg/m(2)). CONCLUSIONS: ILD following FOLFOX or FOLFIRI is an uncommon but life-threatening complication. Care must be taken regarding the onset of ILD, not only during but also after chemotherapy for CRC.

Glucagon-like peptide-1 (GLP-1) protects against methylglyoxal-induced PC12 cell apoptosis through the PI3K/Akt/mTOR/GCLc/redox signaling pathway.

Patients with long-standing diabetes commonly develop diabetic encephalopathy, which is characterized by cognitive impairment and dementia. Oxidative stress-induced neuronal cell apoptosis is a contributing factor. Glucagon-like peptide (GLP)-1 has recently become an attractive treatment modality for patients with diabetes. It also readily enters the brain, prevents neuronal cell apoptosis, and improves the cognitive impairment characteristic of Alzheimer's disease. Therefore, we investigated whether GLP-1 could protect against oxidative stress-induced neuronal cell apoptosis in pheochromocytoma (PC12) cells. PC12 cells were exposed to 1 mM methylglyoxal (MG) or MG plus 3.30 microg/ml GLP-1. Cell apoptosis, expression and phosphorylation of phosphatidylinositol-3 kinase/Akt/mammalian target of rapamycin/gamma-glutamylcysteine ligase catalytic subunit (GCLc), and redox balance were then determined. The data showed that MG induced PC12 apoptosis in accordance with the redox (glutathione (GSH) and GSH/glutathione disulfide [GSSG]) imbalance. GLP-1 protected against this MG-induced apoptosis, which corresponded to the phosphorylation of PI3K, Akt, and mTOR, as well as the upregulation of GCLc and the restoration of the redox imbalance. Inhibitors of PI3K (LY294002), Akt (Akt-I), and mTOR (rapamycin) reduced the GLP-1-induced GCLc upregulation and its protection against MG-induced PC12 apoptosis. The GLP-1-induced redox restoration was also attenuated by rapamycin. In conclusion, the neuroprotective effect of GLP-1 is due to an enhancement of PI3K/Akt/mTOR/GCLc/redox signaling.

BCL6 degradation caused by the interaction with the C-terminus of pro-HB-EGF induces cyclin D2 expression in gastric cancers.

BCL6 is a transcriptional repressor that has important functions in lymphocyte differentiation and lymphomagenesis, but there have been no reports of BCL6 expression in gastric cancers. In the present study, we investigated the BCL6 function in gastric cancers. Treatment with TPA resulted in BCL6 degradation and cyclin D2 upregulation. This phenomenon was inhibited by the suppression of the nuclear translocation of HB-EGF-CTF (C-terminal fragment of pro-HB-EGF). The HB-EGF-CTF nuclear translocation leads to the interaction of BCL6 with HB-EGF-CTF and the nuclear export of BCL6, and after that BCL6 degradation was mediated by ubiquitin/proteasome pathway. Real-time RT-PCR and siRNA targeting BCL6 revealed that BCL6 suppresses cyclin D2 expression. Our data indicate that BCL6 interacts with nuclear-translocated HB-EGF-CTF and that the nuclear export and degradation of BCL6 induces cyclin D2 upregulation. We performed immunohistochemical analyses of BCL6, HB-EGF and cyclin D2 in human gastric cancers. The inverse correlation between BCL6 and cyclin D2 was also found in HB-EGF-positive human gastric cancers. BCL6 degradation caused by the HB-EGF-CTF also might induce cyclin D2 expression in human gastric cancers. Inhibition of HB-EGF-CTF nuclear translocation and maintenance of BCL6 function are important for the regulation of gastric cancer progression.

RUNX3 expression correlates with chief cell differentiation in human gastric cancers.

RUNX3 is a novel tumor suppressor in gastric carcinogenesis and an important factor for differentiation of chief cells in the normal gastric fundic mucosa. In this study, we confirmed RUNX3 immunolocalization in the fundic gland (bottom part) but minimum in surface mucous cell epithelium (top part) in the isolated gland from fundic mucosa. We also analyzed RUNX3 expression by immunohistochemistry in 102 gastric cancers and made a histological assessment of the expression of differentiation markers to evaluate interrelations. Among them, 45 and 57 cases were judged to be RUNX3 positive and negative, respectively, and 33 and 69 cases were pepsinogen I positive and negative, with no link to histological types. RUNX3 expression was significantly associated with that of pepsinogen I (P<0.001), but not mucins, including MUC5AC and MUC6, or the parietal or intestinal phenotypes. In conclusion, the present study showed, for the first time to our knowledge, a relation between RUNX3 and pepsinogen I expression in human gastric cancers. RUNX3 is strongly associated with chief cell phenotypic expression in human gastric cancers, as well as in normal gastric mucosa, and could be considered to play an important role in maintaining the chief cell phenotype.

Wip1 protects hydrogen peroxide-induced colonic epithelial barrier dysfunction.

Tight junctions (TJs) create a paracellular permeability barrier. Although reactive oxygen species have been implicated as mediators of inflammation in inflammatory bowel diseases, their influence on the function of colonic epithelial TJs remains unknown. Oxidative stress-mediated colonic epithelial permeability was significantly attenuated by a p38 mitogen-activated protein (MAP) kinase inhibitor, SB203580. Although the amount of TJ proteins was not altered, hydrogen peroxide (H2O2) changed the localization of claudin-4 protein from an NP-40 insoluble fraction to a soluble fraction and from an apical TJ to lateral membrane. The p38 MAP kinase inactivator Wip1 significantly attenuated phosphorylation of p38 MAP kinase, and oxidative stress mediated permeability. H2O2-induced changes in claudin-4 localization were abolished by SB203580 pretreatment as well as Wip1-expressing adenovirus infection. This is the first study to demonstrate that exogenous Wip1 functions to protect oxidative stress-mediated colonic mucosal permeability and that H2O2-induced claudin-4 dislocalization is abolished by Wip1.

Endoscopic submucosal dissection is useful and safe for intramucosal gastric neoplasms in the elderly.

BACKGROUND AND STUDY AIMS: Endoscopic submucosal dissection (ESD) has recently gained popularity for use against intramucosal gastric neoplasms in Japan, but few studies have examined whether ESD is feasible for elderly patients. This study aims are to evaluate the efficacy and safety of ESD according to age in consecutive elderly patients treated with ESD. PATIENTS AND METHODS: Subjects comprised 116 patients (90 men, 26 women) with 125 lesions treated using ESD from November 2002 to March 2006 at Nagoya City University Hospital and Iwata Municipal Hospital, Japan. Patients were categorized into: Group A, <65-years-old (n=34); Group B, > or =65-years-old but <75-years-old (n=41); and Group C, > or = 75-years-old (n=41). En bloc resection rate and treatment time were examined according to age, tumour size and location, and frequency of complications was examined according to age. RESULTS: Rate of concomitant disease was significantly higher in Group C than in the other groups. En bloc resection rates and median treatment times were 91.4% and 80 min in Group A, 91.1% and 97 min in Group B and 86.7% and 110 min in Group C, respectively. No significant differences were noted between groups, or for en bloc resection rate and treatment time according to tumour size and location, or between groups for frequency of complications. CONCLUSIONS: ESD for gastric neoplasms is effective and safe in elderly patients, and may be positively recommended to elderly patients with intramucosal gastric neoplasms.