Hideyuki Yoshitomi

Endothelial cell interactions initiate dorsal pancreas development by selectively inducing the transcription factor Ptf1a

Dorsal and ventral pancreatic bud development from the endoderm requires inductive interactions with diverse mesodermal cell types and the action of transcription factors expressed within the endoderm. Presently it is unclear which mesodermal interactions activate which pancreatic transcription factors, and whether such inductions are common for initiating dorsal and ventral pancreas development. Previous studies of Lammert et al. (Lammert, E., Cleaver, O. and Melton, D. (2001) Science 294, 564-567) showed that signaling from embryonic blood vessel cells, derived from the mesoderm, promotes pancreatic bud development. Using a combination of mouse Flk1-/- embryos lacking endothelial cells and tissue recombination experiments, we discovered that the initial induction of dorsal endoderm cells positive for the pancreatic and duodenal transcription factor Pdx1 does not require aorta or endothelial cell interactions, but dorsal pancreatic bud emergence and the maintenance of Pdx1 expression does. Aortal endothelial cells induce the crucial pancreatic transcription factor Ptf1a in the dorsal pancreatic endoderm; whereas the vitelline veins, which are normally adjacent to the emerging ventral pancreatic bud, are unnecessary for ventral Ptf1a induction or for ventral pancreatic bud initiation. We find that the aorta cells themselves, apart from the blood supply, cause the induction of Ptf1a in dorsal endoderm explants. Thus, endothelial cell interactions specifically promote early dorsal pancreatic development, at least in part, by inducing Ptf1a+ pancreatic progenitors. Additionally, we find that endothelial cells are necessary for the induction of both the insulin and glucagon genes.

Guidelines for the management of biliary tract and ampullary carcinomas: surgical treatment

The only curative treatment in biliary tract cancer is surgical treatment. Therefore, the suitability of curative resection should be investigated in the first place. In the presence of metastasis to the liver, lung, peritoneum, or distant lymph nodes, curative resection is not suitable. No definite consensus has been reached on local extension factors and curability. Measures of hepatic functional reserve in the jaundiced liver include future liver remnant volume and the indocyanine green (ICG) clearance test. Preoperative portal vein embolization may be considered in patients in whom right hepatectomy or more, or hepatectomy with a resection rate exceeding 50%–60% is planned. Postoperative complications and surgery-related mortality may be reduced with the use of portal vein embolization. Although hepatectomy and/or pancreaticoduodenectomy are preferable for the curative resection of bile duct cancer, extrahepatic bile duct resection alone is also considered in patients for whom it is judged that curative resection would be achieved after a strict diagnosis of its local extension. Also, combined caudate lobe resection is recommended for hilar cholangiocarcinoma. Because the prognosis of patients treated with combined portal vein resection is significantly better than that of unresected patients, combined portal vein resection may be carried out. Prognostic factors after resection for bile duct cancer include positive surgical margins, especially in the ductal stump; lymph node metastasis; perineural invasion; and combined vascular resection due to portal vein and/or hepatic artery invasion. For patients with suspected gallbladder cancer, laparoscopic cholecystectomy is not recommended, and open cholecystectomy should be performed as a rule. When gallbladder cancer invading the subserosal layer or deeper has been detected after simple cholecystectomy, additional resection should be considered. Prognostic factors after resection for gallbladder cancer include the depth of mural invasion; lymph node metastasis; extramural extension, especially into the hepatoduodenal ligament; perineural invasion; and the degree of curability. Pancreaticoduodenectomy is indicated for ampullary carcinoma, and limited operation is also indicated for carcinoma in adenoma. The prognostic factors after resection for ampullary carcinoma include lymph node metastasis, pancreatic invasion, and perineural invasion.

Aggressive surgical resection for hepatic metastases involving the inferior vena cava

BACKGROUND The implications of aggressive surgical approaches for hepatic metastases involving the inferior vena cava (IVC) have not been clarified yet. The aim of this study is to assess the preliminary results of aggressive surgical resection for hepatic metastases involving the IVC. METHODS Sixteen patients with hepatic metastases involving the IVC underwent surgical resections with the repair and reconstruction of the IVC: patch repair in 2 and ringed Goretex in 1, primary closure in 13 patients. Hepatic metastases were from colorectal cancer in 14, stomach cancer in 1, and uterine cancer in 1 patient. RESULTS Vascular control utilized for resecting the IVC were total hepatic vascular exclusion in 8, hypothermic isolated hepatic perfusion in 3, and side clamp in 5 patients. The combined IVC resection with hepatectomy in 16 patients brought about 25% and 6% surgical morbidity and mortality rates, respectively. Survival rates following surgical resections were 64%, 33%, 33%, 22%, 22% for 14 patients of colorectal metastases involving the IVC as compared with 82%, 58%, 41%, 37%, 27% at 1, 2, 3, 4, 5 years, respectively, for 154 patients of colorectal metastases not involving the IVC. CONCLUSION Hepatic metastases involving the IVC could be safely resected without an increase in surgical risk. Aggressive surgical approaches might bring about a favorable outcome in select patients with colorectal hepatic metastases involving the IVC.

FGF10/FGFR2 signal induces cell migration and invasion in pancreatic cancer

Pancreatic cancer has one of the highest mortalities among all malignancies and there is an urgent need for new therapy. This might be achieved by resolving the detailed biological mechanism, and in this study we examined how pancreatic cancer cells develop aggressive properties by focusing on signalling through the fibroblast growth factor (FGF)10 and FGF receptor (FGFR)2, which play important roles in pancreatic organogenesis. Immunostaining of pancreatic cancer tissues showed that FGFR2 was expressed in cancer cells, whereas FGF10 was expressed in stromal cells surrounding the cancer cells. Patients with high FGFR2 expression in cancer cells had a shorter survival time compared to those with low FGFR2 expression. Fibroblast growth factor 10 induced cell migration and invasion of CFPAC-1 and AsPC-1 pancreatic cancer cells through interaction with FGFR2-IIIb, a specific isoform of FGFR2. Fibroblast growth factor 10 also induced expression of mRNA for membrane type 1-matrix metalloproteinase (MT1-MMP) and transforming growth factor (TGF)-β1, and increased secretion of TGF-β1 protein from these cell lines. These data indicate that stromal FGF10 induces migration and invasion in pancreatic cancer cells through interaction with FGFR2, resulting in a poor prognosis. This suggests that FGF10/FGFR2 signalling is a promising target for new molecular therapy against pancreatic cancer.

Usefulness of intraoperative fluorescence imaging to evaluate local anatomy in hepatobiliary surgery.

BACKGROUND/PURPOSE One of the major complications encountered in hepatobiliary surgery is the incidence of bile duct and blood vessel injuries. It is sometimes difficult during surgery to evaluate the local anatomy corresponding to hepatic arteries and bile ducts. We investigated the potential utility of an infrared camera system as a tool for evaluating local anatomy during hepatobiliary surgery. METHODS An infrared camera system was used to detect indocyanine green fluorescence in vitro. We also employed this system for the intraoperative fluorescence imaging of the arteries and biliary system in a pig. Further, we evaluated blood flow in the hepatic artery, portal vein, and liver parenchyma during a human liver transplant and we investigated local anatomy in patients undergoing cholecystectomy. RESULTS Fluorescence confirmed that indocyanine green was distributed in serum and bile. In the pig study, we confirmed the fluorescence of the biliary system for more than 1 h. In the liver transplant recipient, blood flow in the hepatic artery and portal vein was confirmed around the anastomosis. In most of the patients undergoing cholecystectomy, fluorescence was observed in the gallbladder, cystic and common bile ducts, and hepatic and cystic arteries. CONCLUSIONS Intraoperative fluorescence imaging in hepatobiliary surgery facilitates better understanding of the anatomy of arteries, the portal vein, and bile ducts.

Preoperative biliary drainage for biliary tract and ampullary carcinomas

We posed six clinical questions (CQ) on preoperative biliary drainage and organized all pertinent evidence regarding these questions. CQ 1. Is preoperative biliary drainage necessary for patients with jaundice? The indications for preoperative drainage for jaundiced patients are changing greatly. Many reports state that, excluding conditions such as cholangitis and liver dysfunction, biliary drainage is not necessary before pancreatoduodenectomy or less invasive surgery. However, the morbidity and mortality of extended hepatectomy for biliary cancer is still high, and the most common cause of death is hepatic failure; therefore, preoperative biliary drainage is desirable in patients who are to undergo extended hepatectomy. CQ 2. What procedures are appropriate for preoperative biliary drainage? There are three methods of biliary drainage: percutaneous transhepatic biliary drainage (PTBD), endoscopic nasobiliary drainage (ENBD) or endoscopic retrograde biliary drainage (ERBD), and surgical drainage. ERBD is an internal drainage method, and PTBD and ENBD are external methods. However, there are no reports of comparisons of preoperative biliary drainage methods using randomized controlled trials (RCTs). Thus, at this point, a method should be used that can be safely performed with the equipment and techniques available at each facility. CQ 3. Which is better, unilateral or bilateral biliary drainage, in malignant hilar obstruction? Unilateral biliary drainage of the future remnant hepatic lobe is usually enough even when intrahepatic bile ducts are separated into multiple units due to hilar malignancy. Bilateral biliary drainage should be considered in the following cases: those in which the operative procedure is difficult to determine before biliary drainage; those in which cholangitis has developed after unilateral drainage; and those in which the decrease in serum bilirubin after unilateral drainage is very slow. CQ 4. What is the best treatment for postdrainage fever? The most likely cause of high fever in patients with biliary drainage is cholangitis due to problems with the existing drainage catheter or segmental cholangitis if an undrained segment is left. In the latter case, urgent drainage is required. CQ 5. Is bile culture necessary in patients with biliary drainage who are to undergo surgery? Monitoring of bile cultures is necessary for patients with biliary drainage to determine the appropriate use of antibiotics during the perioperative period. CQ 6. Is bile replacement useful for patients with external biliary drainage? Maintenance of the enterohepatic bile circulation is vitally important. Thus, preoperative bile replacement in patients with external biliary drainage is very likely to be effective when highly invasive surgery (e.g., extended hepatectomy for hilar cholangiocarcinoma) is planned.

Identification of novel immunohistochemical tumor markers for primary hepatocellular carcinoma; clathrin heavy chain and formiminotransferase cyclodeaminase

Early diagnosis of hepatocellular carcinoma (HCC) greatly improves its prognosis. However, the distinction between benign and malignant tumors is often difficult, and novel immunohistochemical markers are necessary. Using agarose two‐dimensional fluorescence difference gel electrophoresis, we analyzed HCC tissues from 10 patients. The fluorescence volumes of 48 spots increased and 79 spots decreased in tumor tissues compared with adjacent nontumor tissue, and 83 proteins were identified by mass spectrometry. Immunoblot confirmed that the expression of clathrin heavy chain (CHC) and Ku86 significantly increased, whereas formiminotransferase cyclodeaminase (FTCD), rhodanese, and vinculin decreased in tumor. The protein expression in tumor and nontumor tissues was further evaluated by immunostaining. Interestingly, CHC and FTCD expression was strikingly different between tumor and nontumor tissues. The sensitivity and specificity of individual markers or a combination for the detection of HCC were 51.8% and 95.6% for CHC, 61.4% and 98.5% for FTCD, and 80.7% and 94.1% for CHC+FTCD, respectively. Strikingly, the sensitivity and specificity increased to 86.7% and 95.6% when glypican‐3, another potential biomarker for HCC, was used with FTCD. Moreover, CHC and FTCD were useful to distinguish early HCC from benign tumors such as regenerative nodule or focal nodular hyperplasia, because the sensitivity and specificity of the markers are 41.2% and 77.8% for CHC, 44.4% and 80.0% for FTCD, which is comparable with those of glypican‐3 (33.3% and 100%). The sensitivity significantly increased by combination of these markers, 72.2% for CHC+FTCD, and 61.1% for CHC+glypican‐3 and FTCD+glypican‐3, as 44.4% of glypican‐3 negative early HCC were able to be detected by either CHC or FTCD staining. Conclusion: Immunostaining of CHC and FTCD could make substantial contributions to the early diagnosis of HCC. (HEPATOLOGY 2008.)

Aggressive Surgical Resection for Hilar Cholangiocarcinoma of the Left-Side Predominance: Radicality and Safety of Left-Sided Hepatectomy

Objectives:To evaluate the clinicopathologic outcomes in patients with hilar cholangiocarcinoma (HC) after left-sided hepatectomy (L-H). Summary Background Data:L-H is indicated as radical surgery for HC, predominantly involving left hepatic duct. However, several reports have demonstrated that L-H often results in tumor-positive margin and unfavorable prognosis compared with right-sided hepatectomy (R-H). Methods:A total of 224 patients with HC underwent surgical resection with curative intent at our institution: L-H for Bismuth-Corlette (B-C) type IIIb tumors in 88 patients (39.3%) including 75 left hemihepatectomies and 13 left trisectionectomies, and R-H mainly for B-C type IIIa and IV tumors in 84 patients (37.5%). In this study, clinicopathologic outcomes and perioperative morbidity and mortality rates after L-H were investigated and compared with those after R-H. Results:Histologically negative margin (R0) resection was achieved in 56 cases (63.6%) with L-H, similar to the results for R-H (58/84, 69.1%). However, the R0 resection rate in L-H cases with portal vein (PV) resection was lower (11/25, 44.0%), and various types of PV reconstruction were required. Proximal ductal stumps and excisional surface at periductal structures were the most common sites of positive margins. However, when curative resection was achieved, 5-year survival was comparable to that in R-H cases. Furthermore, lower mortality was noted in L-H cases, even with left trisectionectomy. Multivariate analysis indicated curability and hepatic artery resection as independent prognostic factors. Conclusions:Since L-H is a safe procedure and represents the only curative resectional option for type IIIb tumor, aggressive surgical resection should be performed even in cases with PV involvement, if R0 resection is possible.

Similarities and differences between intraductal papillary tumors of the bile duct with and without macroscopically visible mucin secretion.

Intraductal papillary neoplasms of the bile duct (IPNB) have been recently proposed as the biliary counterpart of intraductal papillary mucinous neoplasms of the pancreas (IPMN-P). However, in contrast to IPMN-P, IPNB include a considerable number of the tumors without macroscopically visible mucin secretion. Here we report the similarities and differences between IPNB with and without macroscopically visible mucin secretion (IPNB-M and IPNB-NM). Surgically resected 27 consecutive cases with IPNB were divided into IPNB-M (n=10) and IPNB-NM (n=17), and their clinicopathologic features were examined. Clinically, both tumors were similar. Pathologically, the most frequent histopathologic types were pancreatobiliary in IPNB-NM and intestinal in IPNB-M. Various degrees of cytoarchitectural atypia within the same tumor were exhibited in 8 IPNB-M, but only 3 in IPNB-NM. Although the tumor size was similar, 9 IPNB-NM were invasive carcinoma, whereas all but 1 IPNB-M with carcinoma were in situ or minimally invasive. Immunohistochemically, positive MUC2 expression was significantly more frequent in IPNB-M than in IPNB-NM, whereas MUC1 tended to be more frequently expressed in IPNB-NM compared with IPNB-M. Among IPNB-NM with positive MUC1 expression, 3 had negative MUC2 and MUC5AC expressions. These tumors showed a tubulopapillary growth with uniform degree of cytoarchitectural atypia. All IPNB-M were negative for p53, and the frequency of positive p53 protein in IPNB-NM was at the middle level of that in IPNB-M and nonpapillary cholangiocarcinoma. In conclusion, IPNB-M showed striking similarities to IPMN-P, but IPNB-NM contained heterogeneous disease groups.

Risk factors for biliary tract and ampullary carcinomas and prophylactic surgery for these factors

Curative resection is the only treatment for biliary tract cancer that achieves long-term survival. However, patients with advanced biliary tract cancer have only a limited prognosis even after radical surgical resection. Thus, to improve the longterm results, the early detection of biliary tract cancer and subsequent cure seem to be essential. The purpose of this study was to review the literature concerning the risk factors for cancerous and precancerous lesions of the biliary tract, and prophylactic surgery for these factors. It has been reported that pancreaticobiliary maljunction (PBM) with bile duct dilatation is a risk factor for gallbladder cancer and bile duct cancer, while PBM without bile duct dilatation is a risk factor for gallbladder cancer. Thus, in the former group, a prophylactic excision of the common bile duct and gallbladder should be recommended, while in the later group, a prophylactic cholecystectomy without bile duct resection may be the appropriate surgical procedure. It has also been reported that primary sclerosing cholangitis (PSC) is a risk factor for cholangiocarcinoma. Patients with PSC often develop advanced cholangiocarcinoma with a poor prognosis. In patients with PSC, therefore, strict follow-up should be recommended. Adenoma and dysplasia have been regarded as precancerous lesions of gallbladder cancer. A polypoid lesion of the gallbladder that is sessile, has a diameter greater than 10 mm, and /or grows rapidly, is highly likely to be cancerous and should be resected. Although gallstones seem to be closely associated with gallbladder cancer, there is no evidence of a direct causal relationship between gallstones and gallbladder cancer. Thus, a cholecystectomy is not advised for asymptomatic cholecystolithiasis. Controversy remains as to whether adenomyomatosis of the gallbladder and porcelain gallbladder are associated with gallbladder cancer. With respect to ampullary carcinoma, adenoma of the ampulla is considered to be a precancerous lesion. This article discusses the risk factors for cancerous and precancerous lesions of the biliary tract and prophylactic treatment for these factors.