Hiroo Imazu

Vascular endothelial growth factor and receptor interaction is a prerequisite for murine hepatic fibrogenesis

Background: It has been shown that expression of the potent angiogenic factor, vascular endothelial growth factor (VEGF), and its receptors, flt-1 (VEGFR-1) and KDR/Flk-1 (VEGFR-2), increased during the development of liver fibrosis. Aims: To elucidate the in vivo role of interaction between VEGF and its receptors in liver fibrogenesis. Methods: A model of CCl4 induced hepatic fibrosis was used to assess the role of VEGFR-1 and VEGFR-2 by means of specific neutralising monoclonal antibodies (R-1mAb and R-2mAb, respectively). R-1mAb and R-2mAb were administered after two weeks of treatment with CCl4, and indices of fibrosis were assessed at eight weeks. Results: Hepatic VEGF mRNA expression significantly increased during the development of liver fibrosis. Both R-1mAb and R-2mAb treatments significantly attenuated the development of fibrosis associated with suppression of neovascularisation in the liver. Hepatic hydroxyproline and serum fibrosis markers were also suppressed. Furthermore, the number of α-smooth muscle actin positive cells and α1(I)-procollagen mRNA expression were significantly suppressed by R-1mAb and R-2mAb treatment. The inhibitory effect of R-2mAb was more potent than that of R-1mAb, and combination treatment with both mAbs almost completely attenuated fibrosis development. Our in vitro study showed that VEGF treatment significantly stimulated proliferation of both activated hepatic stellate cells (HSC) and sinusoidal endothelial cells (SEC). VEGF also significantly increased α1(I)-procollagen mRNA expression in activated HSC. Conclusions: These results suggest that the interaction of VEGF and its receptor, which reflected the combined effects of both on HSC and SEC, was a prerequisite for liver fibrosis development.

Magnifying endoscopy combined with narrow-band imaging for differential diagnosis of superficial depressed gastric lesions

BACKGROUND AND AIM Magnifying endoscopy combined with narrow-band imaging (ME-NBI) has been used for differential diagnosis of various focal lesions. The aim of our study was to evaluate ME-NBI criteria for cancer diagnosis in superficial depressed gastric lesions in comparison to conventional white light endoscopy (WLE). PATIENTS AND METHODS ME-NBI and WLE images of 100 superficial gastric depressions (55 depressed cancers, 45 benign depressions) were independently evaluated by 11 endoscopists blinded to the diagnosis in each case. The presence or absence of predefined ME-NBI findings relating to microvasculature and fine mucosal structure (FMS) was recorded. A general diagnosis of benign or malignant also had to be given on the basis of a general assessment of features of color and shape as shown in the ME-NBI and WLE images, respectively, without regard to any prespecified criteria. RESULTS Multivariate and ROC analysis demonstrated that the triad of FMS disappearance, microvascular dilation, and heterogeneity appeared to be the best combination for diagnosis of gastric cancer. ME-NBI diagnosis with the triad attained a good specificity (85 %, theoretically calculated if all of the triad were positive), which was significantly ( P < 0.001) superior to WLE general diagnosis (65 %), and comparable with ME-NBI general diagnosis (80 %). The sensitivities of the three diagnoses (ME-NBI with the triad 69 %, WLE general diagnosis 71 %, ME-NBI general diagnosis 72 %) were comparably moderate. The kappa values (interobserver concordance) for ME-NBI diagnosis with the triad (0.47) and ME-NBI general diagnosis (0.48) were superior to the kappa value for WLE diagnosis (0.34). CONCLUSION The triad of FMS disappearance, microvascular dilation, and heterogeneity has good specificity for the diagnosis of superficial depressed gastric carcinoma, but the sensitivity needs to be improved.

TISSUE INHIBITOR OF METALLOPROTEINASES-1 (TIMP-1) INHIBITS TUMOR GROWTH AND ANGIOGENESIS IN THE TIMP-1 TRANSGENIC MOUSE MODEL

The tissue inhibitor of matrix metalloproteinases‐1 (TIMP‐1) has been recognized as a multifunctional protein. The role of TIMPs in cancer remains the subject of conflicting reports with an antitumor activity or a tumor growth stimulation activity by several mechanisms. The aim of our study is to investigate the effect of ectopic TIMP‐1 overexpression on the primary transplanted tumor growth. We employed transgenic mice overexpressing the human TIMP‐1 (hTIMP‐1) in the liver under control of the albumin promoter/enhancer (TIMP‐Tg‐mice) and producing high serum levels of TIMP‐1. We used the transplantable Ehrlich tumor cells in the current study. The allograft study revealed that the tumor growth in the TIMP‐Tg‐mice was more significantly inhibited than control (Cont) mice by associated suppression of neovascularization in the tumor. The in vitro studies showed that the recombinant TIMP‐1 (rTIMP‐1) did not affect the proliferation of the endothelial cells (ECs) and tumor cells, suggesting that the tumor suppressive effect of TIMP‐1 was not due to cytotoxicity. TIMP‐1 significantly inhibited EC tubular formation in vitro. Furthermore, TIMP‐1 treatment did not affect the levels of matrix metalloproteinase (MMP)‐2 and MMP‐9 mRNA in the Ehrlich tumor cells in vitro, although these expressions in the tumor were markedly suppressed in the TIMP‐Tg‐mice, compared to the Cont‐mice at the end of the experiment. These results suggested that the ectopically overexpressed TIMP‐1 inhibited the tumor growth by angiogenesis suppression.

Inhibition of renin–angiotensin system attenuates liver enzyme-altered preneoplastic lesions and fibrosis development in rats

BACKGROUND/AIMS It is suggested that the renin-angiotensin system (RAS) is involved in tumor development and fibrogenesis. The aim of the present study was to examine the effect of RAS inhibition on the liver enzyme-altered preneoplastic lesions and fibrosis development. METHODS The effects of the clinically used angiotensin-I converting enzyme inhibitor (ACE-I), perindopril (PE), on two different rat model of liver carcinogenesis models induced separately by diethylnitrosamine (DEN) and a choline-deficient L-amino acid-defined (CDAA) diet were studied. This CDAA model was also used to elucidate the effect of PE on liver fibrosis development. RESULTS The immunohistochemical evaluation revealed that the glutathione S-transferase placental form (GST-P), and gamma-glutamyltransferase (GGT)-positive preneoplastic foci significantly decreased in the livers of the PE-treated groups. In CDAA-induced liver fibrosis model, PE revealed a marked inhibitory effect of liver fibrosis development. The hepatic hydroxyproline, serum fibrosis markers, alpha-smooth muscle actin (alpha-SMA) immunopositive cells in number, and alpha-(III) pro-collagen mRNA expression were significantly suppressed by PE treatment. These inhibitory effects of PE were achieved even at a clinically comparable dose (2 mg/kg per day). CONCLUSIONS These results suggested that the RAS is involved in liver carcinogenesis and fibrosis development.

New approach to diagnosing ampullary tumors by magnifying endoscopy combined with a narrow-band imaging system

BackgroundA newly developed narrow-band imaging (NBI) system, which uses modified optical filters, can yield clear images of microvessels and surface structure in gastric and colonic diseases. In the present study, we investigated the ability of magnifying endoscopy with NBI (MENBI) to diagnose and differentiate between benign and malignant ampullary tumors.MethodsFourteen patients, whose ampullas were noted to be significantly enlarged or protruding with conventional endoscopy, were enrolled in the study. Specimens, which were obtained by forceps biopsy, endoscopic papillectomy, and/or surgery, were retrieved for histopathological examination. The correlation between MENBI images and histopathological findings was investigated. MENBI findings were classified as I, oval-shaped villi; II, pinecone/leaf-shaped villi; or III, irregular/nonstructured. In addition, tortuous, dilated, and network-like vessels noted on the ampullary lesions with MENBI were defined as abnormal vessels.ResultsIn 6 of 14 patients, the ampullary changes were proven to be inflammatory in forceps biopsy specimens, without any evidence of malignancy after more than 1 year of follow-up. In five patients, ampullary lesions were treated by endoscopic papillectomy, and in three, by pancreatoduodenectomy. All adenomas and adenocarcinomas had type II and/or type III surface structures, and patients whose ampulla had a type I surface structure had only inflammatory or hyperplastic changes. In addition, abnormal vessels were seen only in adenocarcinomas and never in adenomas.ConclusionsMENBI has the ability and potential to predict histological characteristics of ampullary lesions.

Contrast-enhanced harmonic EUS with novel ultrasonographic contrast (Sonazoid) in the preoperative T-staging for pancreaticobiliary malignancies.

Abstract Objective. Sonazoid is a new second-generation microbubble contrast for ultrasonography. In this pilot study, the diagnostic role of contrast-enhanced harmonic imaging endoscopic ultrasonography (CH-EUS) with Sonazoid was prospectively evaluated in preoperative T-staging of pancreaticobiliary malignancies. Patients and methods. Patients with suspected pancreaticobiliary malignancies underwent CH-EUS by a single examiner. After the lesions were observed carefully with conventional harmonic imaging EUS (H-EUS), CH-EUS was performed with intravenous injection of Sonazoid. A reviewer who was blinded reviewed the recordings of H-EUS and CH-EUS and assessed the T-staging. The accuracy of H-EUS and CH-EUS for T-staging was compared to the results of surgical histopathology in patients who underwent surgery. Result. Twenty-six patients underwent surgical resection and could be included in the study. The final diagnosis were pancreatic cancer in 11, bile duct cancer in 7, gallbladder cancer in 4 and ampullary cancer in 4. The overall accuracy of H-EUS and CH-EUS for T-staging were 69.2 (18/26) and 92.4% (24/26), respectively (p < 0.05). There were disagreement in six cases between H-EUS and CH-EUS. CH-EUS staged correctly in all of these six cases, whereas H-EUS misdiagnosed the depth of invasion in one case of gallbladder cancer and one case of ampullary cancer, and invasion of portal vein in two cases of pancreatic cancer and two cases of bile duct cancer. Conclusion. The depth of invasion of biliary cancer and vascular invasion of pancreatic and biliary cancer could be demonstrated more clearly with CH-EUS compared to H-EUS. CH-EUS has the potential to improve the diagnostic accuracy of preoperative T-staging of pancreaticobiliary malignancies.

A Prospective Comparison of EUS-Guided FNA Using 25-Gauge and 22-Gauge Needles

Background and Aims. There are limited data on the differences in diagnostic yield between 25-gauge and 22-gauge EUS-FNA needles. This prospective study compared the difference in diagnostic yield between a 22-gauge and a 25-gauge needle when performing EUS-FNA. Methods. Forty-three patients with intraluminal or extraluminal mass lesions and/or lymphadenopathy were enrolled prospectively. EUS-FNA was performed for each mass lesion using both 25- and 22-gauge needles. The differences in accuracy rate, scoring of needle visibility, ease of puncture and quantity of obtained specimen were evaluated. Results. The overall accuracy of 22- and 25-gauge needle was similar at 81% and 76% respectively (N.S). Likewise the visibility scores of both needles were also similar. Overall the quantity of specimen obtained higher with the 22-gauge needle (score: 1.64 vs. P < .001). However the 25-gauge needle was significantly superior to the 22-gauge needle in terms of ease of puncture (score: 1.9 vs. 1.29, P < .001) and in the quantity of specimen in the context of pancreatic mass EUS-FNA (score: 1.8 vs. 1.58, P < .05). Conclusion. The 22-gauge and 25-gauge needles have similar overall diagnostic yield. The 25-gauge needle appeared superior in the subset of patients with hard lesions and pancreatic masses.

Endothelin-1 plays a major role in portal hypertension of biliary cirrhotic rats through endothelin receptor subtype B together with subtype A in vivo

BACKGROUND/AIMS Endothelin-1 has been suggested to play a key role in cirrhotic portal hypertension, but a role of its receptors in vivo is not fully elucidated. METHODS Biliary cirrhosis was induced by bile duct ligation. Expressions of endothelin-1 and its receptors were evaluated by radioimmunoassay and/or reverse-transcription polymerase chain reaction. Hemodynamics were studied using endothelin receptor agonist or antagonist. RESULTS Portal pressure and hepatic endothelin-1 concentrations progressively increased in parallel after bile duct ligation. Gene expression of hepatic prepro-endothelin-1 and endothelin B receptor enhanced after bile duct ligation, while that of endothelin A receptor was unchanged. Intraportal administration of endothelin-1 or endothelin B receptor agonist sarafotoxin 6c (0.5 nmol/kg, respectively) progressively raised portal pressure in both sham and cirrhotic rats. Portal hypertensive effect of sarafotoxin 6c was more intense in cirrhotic rats than sham animals. Neither endothelin A receptor antagonist FR139317 (1 mg/kg) nor endothelin B receptor antagonist BQ788 (1 mg/kg) alone ameliorated cirrhotic portal hypertension. Only the combined endothelin A and B blockade was associated with a decrease in portal pressure in cirrhotic rats. CONCLUSIONS These results indicate that endothelin-1 plays a major role in cirrhotic portal hypertension through endothelin receptor subtype B together with subtype A in vivo.

Clinical features of liver disturbance in rheumatoid diseases: clinicopathological study with special reference to the cause of liver disturbance.

Background:Background: Liver disturbance in rheumatoid diseases results not only from liver disease associated with the rheumatoid diseases themselves but also from various other causes. This study aimed to elucidate the clinical features of liver disturbance in rheumatoid diseases, focusing on the cause of this disturbance. Methods: A clinicopathological study was performed in 306 patients (106 with systemic lupus erythematosus, 71 with Sjögrens syndrome, 59 with rheumatoid arthritis, 27 with scleroderma, 30 with polymyositis, and 13 with polyarteritis nodosa). Results: Liver disturbance occurred in 43% of these patients and resulted from various causes. Its degree and duration varied from one cause to another. Liver disease associated with rheumatoid diseases was the leading cause of the liver disturbance in these patients and was characterized by mild and transient liver disturbance (maximum alanine aminotransferase [ALT] level during the study period, 68 ± 8 IU/ml; maximum alkaline phosphatase [ALP] level, 410 ± 31 IU/ml; duration of liver disturbance, 6 ± 2 months). Most patients with this type of liver disease showed minimal change in liver histology, although two-thirds of those evaluated by the international scoring system for autoimmune hepatitis (AIH) were classified as “probable” or “definite”. Eight of 14 patients with histologically proven chronic hepatitis or cirrhosis were infected with hepatotropic virus (7 with hepatitis C virus [HCV] and 1 with hepatitis B virus [HBV]). Five of 9 patients in whom the hepatic lesion progressed had hepatotropic virus infection (4 with HCV and 1 with HBV), and the other 4 patients suffered from autoimmune liver diseases. Conclusions: Liver disease associated with rheumatoid diseases was the leading cause of liver disturbance in these patients and was characterized by mild and transient liver disturbance, whereas progressive liver diseases were often associated with hepatotropic virus, mainly HCV, or autoimmune liver diseases. Liver histology is indispensable for differentiating AIH from liver disease associated with rheumatoid diseases.

Novel quantitative perfusion analysis with contrast-enhanced harmonic EUS for differentiation of autoimmune pancreatitis from pancreatic carcinoma

Abstract Objective. Autoimmune pancreatitis (AIP) is often misdiagnosed as pancreatic carcinoma (PC) despite recent advances in imaging tests. The aim of the study was to evaluate whether the quantitative perfusion analysis using software “Time intensity curve” with contrast-enhanced harmonic EUS (CH-EUS) facilitate the differentiation of AIP from PC. Methods. Consecutive patients with focal AIP and pancreatic carcinoma who underwent CH-EUS from January 2009 to September 2010 were analyzed. CH-EUS was performed with intravenous administration of an ultrasonographic contrast (Sonazoid) and electronic radial echoendoscope. The graph of time intensity curve (TIC) for pancreatic mass was generated to depict the changes in signal intensity over time within the region of interest (ROI). ROI was placed to cover an area with a pancreatic mass lesion. Based on the analysis of TIC, base intensity before injection (BI), peak intensity (PI), time to peak, and maximum intensity gain (MIG: PI-BI) were calculated. Results. Eight patients with focal AIP and twenty-two patients with PC were evaluated by TIC. PI and MIG of mass lesion of AIP were significantly higher than that of PC (21.4 dB vs. 9.6 dB, 17.5 vs. 6.6). Receiver operating characteristics analysis yielded an optimal MIG cutoff value of 12.5 with high sensitivity and specificity. Conclusion. Pancreatic mass lesions of AIP and PC exhibited markedly different patterns with the TIC. This novel diagnostic modality using TIC generated by CH-EUS might offer an opportunity to improve accuracy in the differential diagnosis between pancreatic mass lesion of AIP and PC.