Yoshiaki Kuriu

Intrathoracic esophageal replacement by in situ tissue-engineered esophagus

OBJECTIVE This study aimed to evaluate in situ tissue-engineered esophagus in a canine model after experimental resection and replacement of a full circumferential defect of the intrathoracic esophagus. METHODS Two types of scaffolding were fabricated. In the KF(+) group (n = 6), oral keratinocytes and fibroblasts cultured on human amniotic membrane were sheeted on polyglycolic acid felt with smooth muscle tissue and were then rolled around tubes. In the KF(-) group (n = 6), the same procedure was followed, but the keratinocytes and fibroblasts were omitted. Both scaffolds were wrapped in omentum and implanted in the abdomen. In the KF(+) group, at 3 weeks after implantation, the scaffold developed into a tube with a well-differentiated lumen of stratified squamous cells surrounded by a thick smooth muscle-like tissue (in situ tissue-engineered esophagus). A part of the esophagus was resected and replaced by the graft in the same dogs. RESULTS In the KF(-) group, strictures developed after esophageal replacement, with almost complete obstruction within 2 to 3 weeks. In contrast, in the KF(+) group, the in situ tissue-engineered esophagus showed good distensibility and the dogs remained without feeding problems through 420 days. Esophageal peristalsis transferred food to the stomach, despite the absence of peristaltic activity in the in situ tissue-engineered esophagus itself. The thickness of the squamous epithelial layer and the smooth muscle layer of the in situ tissue-engineered esophagus were similar to that of the adjacent native esophagus. CONCLUSION The in situ tissue-engineered esophagus can successfully replace the intrathoracic esophagus, and this procedure may offer a promising surgical approach to esophageal diseases.

Regeneration of skeletal muscle using in situ tissue engineering on an acellular collagen sponge scaffold in a rabbit model.

Because of the limited ability of skeletal muscle to regenerate, resection of a large amount of muscle mass often results in incomplete recovery due to nonfunctional scar tissue. The aim of this study was to regenerate skeletal muscle using in situ tissue engineering in a rabbit model. In 18 male rabbits, a muscle defect (1.0 × ∼1.0 × ∼0.5 cm) was created in the vastus lateralis of both legs. A piece of cross-linked atelocollagen sponge was then inserted into the defect in one leg, whereas the defect in the other leg was left untreated. Both defects were finally covered with fascia. Twenty-four weeks after surgery, the defect that had been filled with the cross-linked atelocollagen sponge scaffold showed mild concavity and slight adhesion to the fascia, while the control side showed severe scar formation and shrinkage. Histologically, the regenerating myofibers at the site containing the collagen sponge were greater in number, diameter, and length than those at the control site. These results indicate that cross-linked atelocollagen sponge has the potential to act as a scaffold for muscle tissue regeneration.

Effects of a Diverting Stoma on Symptomatic Anastomotic Leakage after Low Anterior Resection for Rectal Cancer: A Propensity Score Matching Analysis of 1,014 Consecutive Patients

BACKGROUND Routine creation of a diverting stoma (DS) in every patient who undergoes low anterior resection (LAR) remains controversial. We aimed to investigate the effect of DS on symptomatic anastomotic leakage (AL) after LAR. STUDY DESIGN Patients with rectal cancer within 10 cm from the anal verge were eligible for this prospective, multicenter, cohort study (UMIN-CTR, number 000004017). Propensity score matching (PSM) was used to compare groups of patients with and without DS. RESULTS One thousand fourteen consecutive patients were registered, of whom 936 patients who underwent LAR were analyzed. Before PSM, the overall rate of symptomatic AL was 13.2% (52 of 394) in patients with DS vs. 12.7% (69 of 542) in cases without DS (p = 0.84). Symptomatic AL requiring re-laparotomy occurred in 4.7% (44 of 936) of all patients, occurring in 1.0% (4 of 394) of patients with DS vs. 7.4% (40 of 542) of patients without DS (p < 0.001). After PSM, the 2 groups were nearly balanced, and the incidence rates of symptomatic AL in patients with and without DS were 10.9% and 15.8% (p = 0.26). The incidences of AL requiring re-laparotomy in patients with and without DS were 0.6% and 9.1% (p < 0.001). Multivariate analysis identified male sex (p < 0.001; odds ratio [OR] 3.2; 95% confidence interval [CI] 1.8 to 5.7) and tumor size (p < 0.001; OR 1.2; 95% CI 1.1 to 1.4) as independent risk factors of symptomatic AL. CONCLUSIONS Diverting stoma did not have a significant relationship with symptomatic AL before and after PSM. However, DS does seem to mitigate the consequences of leakage, reducing the need for urgent abdominal reoperation.

HGF regulates VEGF expression via the c-Met receptor downstream pathways, PI3K/Akt, MAPK and STAT3, in CT26 murine cells

In the present study, we assessed the involvement of hepatocyte growth factor (HGF)/c-Met signalling with vascular endothelial cell growth factor (VEGF) and hypoxia inducible factor (HIF)-1α expression in the downstream pathways phosphatidylinositol 3-kinase (PI3K)/Akt, mitogen-activated protein kinase (MAPK) and signal transducer and activator of transcription 3 (STAT3) in CT26 cells, to determine the mechanisms of the potent anti-angiogenic effect of NK4. We established genetically modified CT26 cells to produce NK4 (CT26-NK4). VEGF expression in subcutaneous CT26 tumours in vivo and in culture supernatants in vitro was determined by ELISA. HIF-1α expression in nuclear extracts was evaluated by western blot analysis. VEGF and HIF-1α mRNA levels were examined by real-time reverse transcription-polymerase chain reaction (RT-PCR). The DNA binding activity of HIF-1α was evaluated using an HIF-1α transcription factor assay kit. Our results demonstrated that VEGF expression was reduced in homografts of CT26-NK4 cells, compared to those of the control cells. In vitro, VEGF expression, which was induced by HGF, was inhibited by anti-HGF antibody, NK4 and by kinase inhibitors (PI3K, LY294002; MAPK, PD98059; and STAT3, Stattic). HGF‑induced HIF‑1α transcriptional activity was also inhibited by the kinase inhibitors. Real-time RT-PCR demonstrated that HGF‑induced HIF‑1α mRNA expression was not inhibited by LY294002 and PD98059, but was inhibited by Stattic. These data suggest that the PI3K/Akt, MAPK and STAT3 pathways, downstream of HGF/c‑Met signalling, are involved in the regulation of VEGF expression in CT26 cells. HGF/c‑Met signalling may be a promising target for anti-angiogenic strategies.

Application of Polyethylene Glycolic Acid Felt with Fibrin Sealant to Prevent Postoperative Pancreatic Fistula in Pancreatic Surgery

ObjectiveThe purpose of this nonrandomized retrospective study was to report our new procedures using polyethylene glycolic acid (PGA) felt with fibrin sealant to prevent severe pancreatic fistula in patients undergoing pancreatic surgery.MethodsFrom 2000 to 2008, 54 and 63 patients underwent pancreaticoduodenectomy (PD) and distal pancreatectomy (DP), respectively. Of those patients, we applied PGA felt with fibrin sealant to 18 PD patients and 26 DP patients. In PD patients, the PGA felt was wrapped around the pancreatic suture site, while in DP patients, the PGA felt was wrapped around the predictive division site. The pancreaticojejunostomy site in PD patients and the cut stump in DP patients were coated with fibrin sealant. We compared the occurrence rates for severe postoperative pancreatic fistula (POPF) that occurred after PD or DP both with and without our new procedures.ResultsBefore introduction of our procedures, severe POPF developed in 14 of 36 PD patients (39%) and 10 of 37 DP patients (27%). In contrast, after introduction of our procedures, the incidence of POPF was only one in both of 18 PD (6%; P = 0.016) and 26 DP (4%; P = 0.017) patients.ConclusionIn summary, our procedure using PGA felt with fibrin sealant may reduce the risk of severe POPF.

Fluorescent detection of peritoneal metastasis in human colorectal cancer using 5-aminolevulinic acid

A precise diagnosis of peritoneal dissemination is necessary to determine the appropriate treatment strategy for colorectal cancer. However, small peritoneal dissemination is difficult to diagnose. 5-aminolevulinic acid (5-ALA) is an intermediate substrate of heme metabolism. The administration of 5-ALA to cancer patients results in tumor-specific accumulation of protoporphyrin IX (PpIX), which emits red fluorescence with blue light irradiation. We evaluated the usefulness of photodynamic diagnosis (PDD) using 5-ALA to detect the peritoneal dissemination of colorectal cancer. EGFP-tagged HT-29 cells were injected into the peritoneal cavity of BALB/c nude mice. After 2 weeks, the mice were given 5-ALA hydrochloride, and metastatic nodules in the omentum were observed with white light and fluorescence images. Twelve colorectal cancer patients suspected to have serosal invasion according to preoperative computed tomography (CT) were enrolled in this study. 5-ALA (15-20 mg per kg body weight) was administered orally to the patients 3 h before surgery. The abdominal cavity was observed under white light and fluorescence. Fluorescence images were analyzed with image analysis software (ImageJ 1.45s, National Institutes of Health, Bethesda, MD, USA). The mice developed peritoneal disseminations. The observed 5-ALA-induced red fluorescence was consistent with the EGFP fluorescent-positive nodules. Peritoneal dissemination was observed with conventional white light imaging in 8 patients. All nodules suspected as being peritoneal dissemination lesions by white light observation were similarly detected by ALA-induced fluorescence. In 1 patient, a small, flat lesion that was missed under white light observation was detected by ALA-induced fluorescence; the lesion was pathologically diagnosed as peritoneal metastasis. In the quantitative fluorescence image analysis, the red/(red + green + blue) ratio was higher in the metastatic nodules compared to the non-metastatic sites of the abdominal wall, fat and liver. We demonstrated better diagnostic accuracy using 5-ALA-PDD compared to conventional laparoscopy in patients with colorectal cancer. 5-ALA-PDD is a promising candidate method for diagnosing peritoneal dissemination of colorectal cancer.

Progression of remnant gastric cancer is associated with duration of follow-up following distal gastrectomy

AIM To re-evaluate the recent clinicopathological features of remnant gastric cancer (RGC) and to develop desirable surveillance programs. METHODS Between 1997 and 2008, 1149 patients underwent gastrectomy for gastric cancer at the Department of Digestive Surgery, Kyoto Prefectural University of Medicine, Japan. Of these, 33 patients underwent gastrectomy with lymphadenectomy for RGC. Regarding the initial gastric disease, there were 19 patients with benign disease and 14 patients with gastric cancer. The hospital records of these patients were reviewed retrospectively. RESULTS Concerning the initial gastric disease, the RGC group following gastric cancer had a shorter interval [P < 0.05; gastric cancer vs benign disease: 12 (2-22) vs 30 (4-51) years] and were more frequently reconstructed by Billroth-I procedure than those following benign lesions (P < 0.001). Regarding reconstruction, RGC following Billroth-II reconstruction showed a longer interval between surgical procedures [P < 0.001; Billroth-II vs Billroth-I: 32 (5-51) vs 12 (2-36) years] and tumors were more frequently associated with benign disease (P < 0.001) than those following Billroth-I reconstruction. In tumor location of RGC, after Billroth-I reconstruction, RGC occurred more frequently near the suture line and remnant gastric wall. After Billroth-II reconstruction, RGC occurred more frequently at the anastomotic site. The duration of follow-up was significantly associated with the stage of RGC (P < 0.05). Patients diagnosed with early stage RGC such as stage I-II tended to have been followed up almost every second year. CONCLUSION Meticulous follow-up examination and early detection of RGC might lead to a better prognosis. Based on the initial gastric disease and the procedure of reconstruction, an appropriate follow-up interval and programs might enable early detection of RGC.

Risk Factors and Management of Postoperative Bile Leakage after Hepatectomy without Bilioenteric Anastomosis

Background/Aims: Bile leakage frequently causes major complications after hepatic resection. We investigated perioperative risk factors and management of postoperative bile leakage after hepatic resection without extrahepatic biliary resection and reconstruction. Methods: We included 247 consecutive patients who underwent elective hepatic resection without bilioenteric anastomosis at our institution between 2002 and 2009. Perioperative risk factors, including patient and surgical variables, were evaluated using univariate and logistic regression analyses. Results: Postoperative bile leakage occurred in 26 patients (10.5%). The surgical drain was retained in 6 patients (23%); 9 (35%) underwent drain salvage and 11 (42%) underwent percutaneous puncture under computed tomography or ultrasound guidance. Eight patients underwent endoscopic nasobiliary drainage (ENBD) for postoperative bile leakage, and bile leakage healed at a median interval of 19.5 days after ENBD. By univariate analysis, postoperative bile leakage was associated with central bisectionectomy, surgical time and intraoperative blood loss. Logistic regression analysis identified central bisectionectomy as an independent risk factor for postoperative bile leakage (p = 0.0003, odds ratio 16.724). Conclusion: Meticulous procedures are necessary during parenchymal hepatic resection, especially during central bisectionectomy. Drain management should be precise in the case of postoperative bile leakage. We believe ENBD may rapidly cure postoperative major bile leakage.

Efficacy of 5-aminolevulinic acid-mediated photodynamic therapy using light-emitting diodes in human colon cancer cells.

5-Aminolevulinic acid (ALA)-mediated photodynamic therapy (PDT) (ALA-PDT) is a highly selective treatment for malignant cells. ALA-PDT has the potential to develop into a novel therapeutic strategy for various types of cancer. Recently, light-emitting diodes (LEDs), which are inexpensive, stable and easier to handle compared to lasers, have been used in PDT as a light source. However, in colorectal cancer (CRC), the efficacy of ALA-PDT in combination with LEDs has not been fully assessed. Therefore, in this study, we evaluated the antitumor effect of ALA-PDT using various LEDs in colon cancer cells. The HT-29 human colon cancer cell line was used both in vitro and in vivo. HT-29 cells were seeded in 96-well plates. Following 5-ALA administration, cells were irradiated using LEDs at different wavelengths. Three types of LEDs, blue (peak wavelength, 456 nm), white (broad-band) and red (635 nm) were used. Twenty-four hours after irradiation, the cytotoxic effects of ALA-PDT were measured using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. In order to evaluate the antitumor effect of ALA-PDT in vivo, nude mice were inoculated with HT-29 cells. Xenograft mice were injected intraperitoneally with 5-ALA and irradiated with 3 types of LEDs at a measured fluence rate of 96 mW/cm2 and fluence of 32 J/cm2. Each group comprised 6 mice. ALA-PDT was repeated 3 times at weekly intervals. Tumor weights were measured. Compared to the controls, ALA-PDT using LEDs showed significant antitumor effects in vitro and in vivo. The blue and white LEDs demonstrated greater antitumor effects compared to the red LEDs in vitro and in vivo. In particular, tumor inhibition rates in the blue and white LED groups were approximately 88% to those of the control group in the mouse models. In conclusion, ALA-PDT using LEDs is effective and useful in the treatment of CRC cells. This method could be a novel treatment modality for CRC.

Differences of the Lymphatic Distribution and Surgical Outcomes Between Remnant Gastric Cancers and Primary Proximal Gastric Cancers

BackgroundAlthough remnant gastric cancer (RGC) following distal gastrectomy is located in the proximal stomach, little is known about the differences of the lymphatic distribution and surgical outcomes between RGC and primary proximal gastric cancer (PGC).MethodsBetween 1997 and 2008, 1,149 patients underwent gastrectomy for gastric cancer. Of these, 33 (2.9%) RGC patients and 207 (18.5%) PGC patients were treated at our department. We reviewed their hospital records retrospectively.ResultsCompared with the PGC patients, those with RGC had a slightly higher age at onset (p = 0.09), higher incidence of undifferentiated cancer (p = 0.06), higher incidence of vascular invasion (p = 0.09), and higher incidence of T4 (p = 0.07). Gastrectomy for RGC involved greater blood loss (p < 0.005), longer surgical duration (p = 0.01), combined resection, and high incidence of complications. However, the survival rate for RGC patients was similar to that for PGC patients (p = 0.67). 2) Patients with RGC had a different pattern of lymph node metastasis compared with that in PGC. Particularly in advanced RGC with pT2–T4 tumors, RGC frequently demonstrated jejunal mesentery lymph node metastases (RGC vs. PGC, 35% vs. 0%) and splenic hilar lymph node metastases (RGC vs. PGC, 17% vs. 10%). The jejunal mesentery lymph node metastases were detected only following Billroth II reconstruction (Billroth I vs. Billroth II, 0% vs. 67%).ConclusionAlthough the clinical behaviors of the two gastric cancers were different, the survival rates were similar. The pattern of metastasis indicates that the jejunal mesentery and splenic hilar lymph nodes should be specifically targeted for en bloc resection during complete gastrectomy in RGC.