Hepatocyte growth factor facilitates the repair of large colonic ulcers in 2,4,6-trinitrobenzene sulfonic acid-induced colitis in rats

BACKGROUND: Hepatocyte growth factor (HGF) modulates intestinal epithelial cell proliferation and migration, serving as a critical regulator of intestinal wound healing. The aim of this study was to clarify the effects of administration of recombinant human HGF on colonic mucosal damage in vivo. METHODS: Rats were given 7.5 mg of 2,4,6-trinitrobenzene sulfonic acid (TNBS) per rectum on day 0. On day 5, the degree of TNBS-induced colitis was evaluated endoscopically, and rats suffering from large ulcers (occupying more than two thirds of the luminal circumference) were treated with intravenous bolus injections of recombinant human HGF (1.0 mg/kg per day) or phosphate-buffered saline (PBS) for 5 days. RESULTS: Rats with TNBS-induced colitis given human HGF showed a significant reduction in colonic ulcer coverage and large intestinal shortening compared with those treated with PBS. Administration of recombinant human HGF also stimulated the proliferation of epithelial cells and reduced the inflammatory cell infiltrate. Finally, HGF treatment decreased the myeloperoxidase activity and tumor necrosis factor alpha levels in the TNBS-inflamed colon tissues. CONCLUSIONS: These results indicate that intravenous injection of HGF accelerates colonic mucosal repair and reduces infiltration of inflammatory cells in rats with TNBS-induced colitis and suggest that HGF has the potential to be a new therapeutic modality to promote intestinal mucosal repair in patients with inflammatory bowel disease.     

Risk factors for bleeding after endoscopic mucosal resection

AIM: To clarify the risk factors for bleeding after endoscopic mucosal resection (EMR). METHODS: A total of 297 consecutive patients who underwent EMR were enrolled. Some of the patients had multiple lesions. Bleeding requiring endoscopic treatment was defined as bleeding after EMR. Odds ratios (OR) with 95% confidence intervals (CI), calculated by logistic regression with multivariate adjustments for covariates, were the measures of association. RESULTS: Of the 297 patients, 57 (19.2%) patients with bleeding after EMR were confirmed. With multivariate adjustment, the cutting method of EMR, diameter, and endoscopic pattern of the tumor were associated with the risk of bleeding after EMR. The multivariate-adjusted OR for bleeding after EMR using endoscopic aspiration mucosectomy was 3.07 (95%CI, 1.59-5.92) compared with strip biopsy. The multiple-adjusted OR for bleeding after EMR for the highest quartile (16-50 mm) of tumor diameter was 5.63 (95%CI, 1.84-17.23) compared with that for the lowest (4-7 mm). The multiple-adjusted OR for bleeding after EMR for depressed type of tumor was 4.21 (95%CI, 1.75-10.10) compared with elevated type. CONCLUSION: It is important to take tumor characteristics (tumor size and endoscopic pattern) and cutting method of EMR into consideration in predicting bleeding after EMR.     

Ca(2+)-sensitive tyrosine kinase Pyk2/CAK beta-dependent signaling is essential for G-protein-coupled receptor agonist-induced hypertrophy

G-protein-coupled receptor agonists including endothelin-1 (ET-1) and phenylephrine (PE) induce hypertrophy in neonatal ventricular cardiomyocytes. Others and we previously reported that Rac1 signaling pathway plays an important role in this agonist-induced cardiomyocyte hypertrophy. In this study reported here, we found that a Ca(2+)-sensitive non-receptor tyrosine kinase, proline-rich tyrosine kinase 2 (Pyk2)/cell adhesion kinase beta (CAKbeta), is involved in ET-1- and PE-induced cardiomyocyte hypertrophy medicated through Rac1 activation. ET-1, PE or the Ca(2+) inophore, ionomycin, stimulated a rapid increase in tyrosine phosphorylation of Pyk2. The tyrosine phosphorylation of Pyk2 was suppressed by the Ca(2+) chelator, BAPTA. ET-1- or PE-induced increases in [(3)H]-leucine incorporation and expression of atrial natriuretic factor and the enhancement of sarcomere organization. Infection of cardiomyocytes with an adenovirus expressing a mutant Pyk2 which lacked its kinase domain or its ability to bind to c-Src, eliminated ET-1- and PE-induced hypertrophic responses. Inhibition of Pyk2 activation also suppressed Rac1 activation and reactive oxygen species (ROS) production. These findings suggest that the signal transduction pathway leading to hypertrophy involves Ca(2+)-induced Pyk2 activation followed by Rac1-dependent ROS production.     

AT1 receptor blocker added to ACE inhibitor provides benefits at advanced stage of hypertensive diastolic heart failure

Diastolic heart failure (DHF) has become a social burden; however, evidences leading to its therapeutic strategy are lacking. This study investigated effects of addition of angiotensin II type 1 receptor blocker (ARB) to angiotensin-converting enzyme inhibitor (ACEI) at advanced stage of DHF in hypertensive rats. Dahl salt-sensitive rats fed 8% NaCl diet from age 7 weeks served as DHF model, and those fed a normal chow served as control. The DHF model rats were arbitrarily assigned to 3 treatment regimens at age 17 weeks: ACEI (temocapril 0.4 mg/kg per day), combination of ACEI (temocapril 0.2 mg/kg per day) with ARB (olmesartan 0.3 mg/kg per day), or placebo. At age 17 weeks, this model represents progressive ventricular hypertrophy and fibrosis, relaxation abnormality, and myocardial stiffening. Data were collected at age 20 weeks. As compared with the monotherapy with ACEI, the addition of ARB induced more prominent suppression of ventricular hypertrophy and fibrosis, leading to suppression of myocardial stiffening, improvement of relaxation, and inhibition of hemodynamic deterioration. Such benefits were associated with greater decreases in reactive oxygen species (ROS) generation, macrophage infiltration, and gene expression of transforming growth factor (TGF)-beta(1) and interleukin (IL)-1beta, but not with changes in gene expression of monocyte chemoattractant protein (MCP)-1 and tumor necrosis factor (TNF)-alpha. Thus, ARB added to ACEI provides more benefits as compared with ACEI alone in DHF when initiated at an advanced stage. The additive effects are likely provided through more prominent suppression of ROS generation and inflammatory changes without effects on expression of MCP-1 and TNF-alpha.     

Selective blockade of serotonin 5-HT2A receptor increases coronary blood flow via augmented cardiac nitric oxide release through 5-HT1B receptor in hypoperfused canine hearts

Serotonin (5-hydroxytryptamine [5-HT]), which induces vasoconstriction via 5-HT2A receptors in smooth muscle cells and vasodilation through activating nitric oxide (NO) synthase (NOS) via 5-HT1B receptors in endothelial cells, possesses divergent effects on regulating vascular tone. These facts lead us to consider that sarpogrelate, a 5-HT2A receptor blocker, may increase coronary blood flow (CBF) via either attenuation of vasoconstriction through 5-HT2A receptor blockade or augmentation of vasodilation by relative stimulation of NOS through 5-HT1B receptor and we tested this hypothesis in ischemic canine hearts. In open chest dogs, coronary perfusion pressure was reduced so that CBF was decreased to 33% of the baseline and kept constant. Thereafter, sarpogrelate was infused selectively into the left anterior descending artery with and without either an inhibitor of NOS (NG-nitro-L-arginine methyl ester (L-NAME)) or a 5-HT1B receptor antagonist (GR55562). An intracoronary administration of sarpogrelate increased CBF (34.0 +/- 4.0 to 44.5 +/- 4.4 ml/100 g/min, P < 0.05), along with the cardiac NOx release (3.2 +/- 0.6 to 6.8 +/- 1.2 nmol/ml, P < 0.05). The increases in both CBF and NOx by sarpogrelate were completely blunted by the co-administration of either L-NAME or GR55562. Interestingly, sarpogrelate increased the cardiac serotonin release (-4.8 +/- 3.2 vs. 22.1 +/- 1.5 ng/ml, P < 0.05, respectively) in the hypoperfused heart. Immunohistochemical analysis showed that sarpogrelate induced serotonin production in ischemic cardiac myocytes. These results suggest that sarpogrelate increases CBF via augmented cardiac NO production through 5-HT1B receptor activation along with the blockade of 5-HT2A receptors. The increase in cardiac release of serotonin may increase NO production in the ischemic heart.     

Activation of RasGRP3 by phosphorylation of Thr-133 is required for B cell receptor-mediated Ras activation

The Ras signaling pathway plays a critical role in B lymphocyte development and activation, but its activation mechanism has not been well understood. At least one mode of Ras regulation in B cells involves a Ras-guanyl nucleotide exchange factor, RasGRP3. We demonstrate here that RasGRP3 undergoes phosphorylation at Thr-133 upon B cell receptor cross-linking, thereby resulting in its activation. Deletion of phospholipase C-gamma2 or pharmacological interference with conventional PKCs resulted in marked reduction in both Thr-133 phosphorylation and Ras activation. Moreover, mutation of Thr-133 in RasGRP3 alone severely impaired its ability to activate Ras in B cell receptor signaling. Hence, our data suggest that PKC, after being activated by diacylglycerol, phosphorylates RasGRP3, thereby contributing to its full activation.     

Add‐on effects of fluvastatin in simeprevir/pegylated‐interferon/ribavirin combination therapy for patients with genotype 1 hepatitis C virus infection: A randomized controlled study

Background

The Japan Society of Hepatology guidelines indicate that hepatitis C virus (HCV) protease inhibitor combination therapy with simeprevir (SMV), pegylated‐interferon (Peg‐IFN), and ribavirin (RBV) is a therapeutic option for patients who fail to respond to a direct direct‐acting antiviral‐containing regimen. However, treatment outcomes have room for improvement. Fluvastatin (FLV) add‐on treatment in Peg‐IFN and RBV combination therapy for HCV‐infected patients significantly improved the sustained virologic response (SVR), but the add‐on effect of FLV on SMV combination therapy is not well understood.

Methods

This was a prospective, randomized, multicenter study in which a total of 61 HCV genotype 1b‐infected patients were recruited and 60 eligible patients were randomly allocated to two groups that received 12 weeks of SMV/Peg‐IFN/RBV followed by 12 weeks of Peg‐IFN/RBV with or without 24 weeks of FLV. The SVR rate and adverse events were compared between the two groups.

Results

Thirty‐one patients were allocated to the FLV add‐on group and 29 patients were allocated to the control group. Baseline clinical factors, including median age, baseline platelet count, alanine aminotransferase level, HCV RNA titer, Fibrosis‐4 index, and rate of IL28B minor genotype, were all similar between the two groups. The rapid virologic response, end‐of‐treatment response rates, SVR rates at 24 weeks after treatment, and safety profiles were also similar between the two groups.

Conclusions

This prospective, randomized, multicenter study indicated that FLV had no add‐on effect when given with SMV/Peg‐IFN/RBV combination therapy for genotype 1b HCV‐infected patients.     

Aspirin attenuates the incidence of silent brain lesions in patients with nonvalvular atrial fibrillation.

BACKGROUND: Abnormal findings, including silent cerebral infarction, are frequently observed by magnetic resonance imaging (MRI) in patients with nonvalvular atrial fibrillation (NVAF); however, the prevalence and prevention strategy for these lesions have not been extensively studied. In the present study the preventive effects of aspirin on silent ischemic lesions was investigated. METHODS AND RESULTS: Silent lesions were counted using cranial MRI performed in 78 neurologically normal adults with sinus rhythm and in 212 patients with NVAF without a history of stroke. MRIs were repeated twice in the NVAF patients at 12-month intervals. During the first year, patients received neither antiplatelet agent nor anticoagulant; in the second year, aspirin (330 mg daily) was administered. The prevalence of lesions in the initial MRI was higher in NVAF patients (86.4%) than in sinus rhythm subjects (53.8%; p<0.001). After 12 months without aspirin, new lesions were seen in 20.6% of NVAF patients. The yearly occurrence of new lesions was decreased to 9.6% during the year of treatment with aspirin (p=0.014). CONCLUSIONS: In patients with NVAF, abnormal lesions are frequently observed by MRI and aspirin treatment may be effective in preventing further small silent lesions.     

Prediction of the no-reflow phenomenon with ultrasonic tissue characterization in patients with anterior wall acute myocardial infarction

The no-reflow phenomenon after acute myocardial infarction seems to be related to ischemic injury before reperfusion. Analyzing cardiac cycle-dependent variation of integrated backscatter (IBS) is a unique method to assess myocardial viability. In this study, the ability of ultrasonic tissue characterization with IBS to predict the no-reflow phenomenon was investigated in 90 patients with first anterior wall infarction who underwent successful primary percutaneous coronary intervention. IBS images were recorded on admission (before reperfusion), and the magnitude of the cyclic variation of IBS within the infarct zone was expressed as phase-corrected magnitude (PCM) by giving positive and negative values when it showed synchronous and asynchronous contraction, respectively. Myocardial contrast echocardiography was performed soon after reperfusion, and 21 patients showed substantial no-reflow. They had smaller PCM before reperfusion than patients without no-reflow (-1.6 +/- 1.9 vs 0.7 +/- 2.7 dB, respectively; p = 0.0002). Multivariate logistic regression analysis revealed that PCM before reperfusion and the number of Q waves were the independent predictors of no reflow. Using -1.0 dB as the cut-off point, PCM predicted no reflow with 66.7% sensitivity and 81.2% specificity. These results indicate that the analysis of myocardial IBS could predict the no-reflow phenomenon before reperfusion.     

A pitfall of the diagnostic process of differentiating bile peritonitis from acute appendicitis

BACKGROUND/AIMS: We often encounter patients with bile peritonitis expressing right hypogastralgia who have been easily misdiagnosed as acute appendicitis. The aim of this study is to clarify why patients with bile peritonitis express right hypogastralgia and to recommend a way in which to prevent misdiagnosis of patients with bile peritonitis with right hypogastralgia as acute appendicitis. METHODOLOGY: Subjects were 12 patients with bile peritonitis who underwent laparotomy in Yokohama City Nambu Hospital or Critical Care and Emergency Center of Yokohama Citizen Medical Center Hospital. The spread of bile and inflammatory peritoneal fluid confirmed during laparotomy was compared with the preoperative abdominal findings. RESULTS: Five of the 12 cases (42%) showed signs of peritoneal irritation only in the epigastric and right hypochondral region; 6 (50%) in the right lateral and hypogastric region; and 1 (8%) in the diffuse abdomen. Four of the 12 cases (33%) showed widespread inflammation and accumulation of fluid in the whole peritoneal cavity (generalized peritonitis). Five cases (42%) showed limited peritoneal inflammation with green coating, leaked bile, and accumulation of inflammatory fluid within the hepatoduodenal ligament, Morison's pouch, right paracolic gutter, and right ileac pouch. Three of these 5 cases and 3 of the 4 generalized peritonitis cases showed signs of peritoneal irritation in the right hypogastric region. US of these cases showed signs of cholecystitis. Three of the 6 cases underwent emergency operation by right hypogastric incision under the diagnosis of acute appendicitis. One of these 3 cases underwent neither US nor CT; the second of these cases showed ileocecal inflammation by US but did not undergo CT; and the last of these cases expressed peritoneal irritation most strongly in the right hypogastric quadrant despite of signs of cholecystitis by US and CT. CONCLUSIONS: If patients who complain of right hypogastralgia like acute appendicitis also complain of right epigastralgia or right hypochondralgia, we should suspect biliary peritonitis due to gangrenous or perforated cholecystitis and should perform upper abdominal scanning, especially around the gallbladder, by US and CT.