Kazuyuki Nagai

Single-institution validation of the international consensus guidelines for treatment of branch duct intraductal papillary mucinous neoplasms of the pancreas

BACKGROUND The international consensus guidelines (the guidelines) for management of intraductal papillary mucinous neoplasms (IPMNs) of the pancreas recommend surgical resection of branch duct IPMNs with any of the following features: cyst size >30 mm, mural nodules, main pancreatic duct diameter >6 mm, positive cytology, and symptoms. The aim of this study was to evaluate the usefulness of these guidelines for resection of branch duct IPMNs. METHODS We reviewed 84 consecutive patients with branch duct IPMNs who underwent surgical resection at our hospital between January 1984 and December 2007. RESULTS Sixty-nine patients had indications for resection according to the guidelines. Malignant IPMNs had significantly larger cysts than benign tumors (P = 0.026). Patients with malignant IPMNs had significantly more indications for resection than those with benign IPMNs (2.6 +/- 1.0 vs. 1.7 +/- 0.9, P < 0.001), and 36 of the 37 patients with malignant IPMNs had indications. The sensitivity of the guidelines for predicting malignancy was 97.3%. One of 15 patients without indications had malignancy, and the specificity was low (29.8%). CONCLUSIONS The guidelines show a high sensitivity for predicting malignancy of branch duct IPMNs, but the specificity is low. The cyst size and the total number of indications in each patient should be taken into account when predicting the risk of malignancy for branch duct IPMNs.

Splenectomy does not offer immunological benefits in ABO-incompatible liver transplantation with a preoperative rituximab.

Background. Preformed anti-ABO antibodies are primarily responsible for antibody-mediated rejection (AMR) after ABO-incompatible (ABO-I) liver transplantation (LT) resulting in lethal hepatic necrosis and biliary complications. Splenectomy, an integral part of protocol for ABO-I LT, decreases anti-ABO antibodies. With the preoperative rituximab prophylaxis, role of the splenectomy for ABO-I LT is now under debate. We investigated the necessity of splenectomy by retrospective analyses of the short-term anti-ABO antibody response and long-term outcomes of ABO-I LT. Methods. Thirty-seven ABO-I LTs performed from May 2006 through July 2009, at Kyoto University Hospital, Kyoto, Japan, were retrospectively analyzed. Twenty-seven patients who underwent splenectomy (splenectomy group) received 329.6±35.8 mg rituximab 17.7±11.9 days before living donor LT. Ten patients without splenectomy (nonsplenectomy group) received 320.0±10.3 mg rituximab 26.6±21.3 days before transplantation. All patients received a posttransplant hepatic artery infusion with prostaglandin E1 and methylprednisolone. Perioperative anti-ABO immunoglobulin M and immunoglobulin G antibody titers, rejections, biliary complications, infections, and survival results were compared. Results. Preoperative rituximab with plasma exchange effectively reduced anti-ABO antibodies in both patient groups at the time of LT. There was no statistically significant difference observed in anti-ABO immunoglobulin M and immunoglobulin G antibody titers between the “splenectomy” and “nonsplenectomy” groups during the initial 8 weeks. The clinical outcomes, including AMR, biliary complications, infections, and survival, were similar in both the groups. Conclusions. Preoperative rituximab effectively decreased the anti-ABO antibodies sufficiently to prevent the AMR irrespective of splenectomy. Splenectomy does not offer any immunological benefit in ABO-I LT with preoperative rituximab.

Prognostic value of metastin expression in human pancreatic cancer

BackgroundKiSS-1 was identified as a metastasis-suppressing gene in melanoma cells. The KiSS-1 gene product (metastin) was isolated from human placenta as the ligand of GPR54, a G-protein-coupled receptor. The role of metastin and GPR54 in tumor progression is not fully understood.MethodsWe investigated the clinical significance of metastin and GPR54 expression in pancreatic cancer. We evaluated immunohistochemical expression of metastin and GPR54 in pancreatic ductal adenocarcinoma tissues obtained from 53 consecutive patients who underwent resection between July 2003 and May 2007 at Kyoto University Hospital. In 23 consecutive patients, the plasma metastin level was measured before surgery by enzyme immunoassay.ResultsStrong immunohistochemical expression of metastin was detected in 13 tumors (24.5%), while strong expression of GPR54 was detected in 30 tumors (56.6%). Tumors that were negative for both metastin and GPR54 expression were significantly larger than tumors that were positive for either metastin or GPR54 (p = 0.047). Recurrence was less frequent in patients who had metastin-positive tumors compared with those who had metastin-negative tumors (38.5% versus 70.0%, p = 0.04). Strong expression of metastin and GPR54 was significantly correlated with longer survival (p = 0.02). Metastin expression by pancreatic cancer was an independent prognostic factor for longer survival (hazard ratio, 2.1; 95% confidence interval, 1.1–4.7; p = 0.03), and the patients with a high plasma metastin level (n = 6) did not die after surgical resection.ConclusionStrong expression of metastin and GPR54 by pancreatic cancer is associated with longer survival. Metastin expression is an independent prognostic factor for the survival of pancreatic cancer patients. The plasma metastin level could become a noninvasive prognostic factor for the assessment of pancreatic cancer.

Impact of venous-systemic oxygen persufflation with nitric oxide gas on steatotic grafts after partial orthotopic liver transplantation in rats.

Background Steatotic livers are associated with poor graft function after transplantation. We investigated the effects of venous-systemic oxygen persufflation with nitric oxide gas (VSOP-NO) on steatotic partial livers after transplantation. Methods Steatotic livers induced by fasting for 2 days and subsequent refeeding for 3 days with a fat-free, carbohydrate-rich diet were reduced in size by 50% and transplanted into Lewis rats after 3 hr of cold storage in histidine-tryptophan-ketoglutarate solution. Gaseous oxygen with nitric oxide (40 ppm) was insufflated into the grafts through the suprahepatic vena cava during cold storage (VSOP-NO group; n=20). Transplantation of cold-static stored steatotic and normal grafts served as controls (Steatotic-Control and Normal-Control, respectively; n=20 for each group). Results The graft microcirculation and portal venous flow were increased by VSOP-NO compared with Steatotic-Control (P<0.001 for both). Serum alanine aminotransferase and interleukin-6 levels were lower in VSOP-NO versus Steatotic-Control group (P=0.03 for both). Messenger RNA expression for inducible nitric oxide synthase, which was increased in Steatotic-Control livers 3 hr after transplantation (P=0.02 vs. that at 1 hr), was suppressed by VSOP-NO. Although serum nitrite levels were decreased 1 hr after transplantation in Steatotic-Control (P=0.06 vs. Normal-Control), the VSOP-NO group showed increased levels comparable to Normal-Control. In livers 24 hr after transplantation, moderate vacuolization of hepatocytes by histology with the immunohistochemical expression of nitrotyrosine, indicative of nitrative stress, was found in Steatotic-Control, whereas these findings were less apparent in VSOP-NO–treated livers. Conclusions Application of VSOP-NO for steatotic partial livers reduces hepatocellular damage and improves graft viability and microcirculation after transplantation.

Impact of venous systemic oxygen persufflation supplemented with nitric oxide gas on cold‐stored, warm ischemia–damaged experimental liver grafts

The increasing shortage of donor organs has led to the increasing use of organs from non–heart‐beating donors. We aimed to assess the impact of venous systemic oxygen persufflation (VSOP) supplemented with nitric oxide (NO) gas during the cold storage (CS) of warm ischemia (WI)–damaged experimental liver grafts. Rat livers (n = 5 per group) were retrieved after 30 minutes of WI induced by cardiac arrest (the WI group) and were thereafter preserved for 24 hours by CS in histidine tryptophan ketoglutarate solution. During CS, gaseous oxygen was insufflated via the caval vein with 40 ppm NO (the VSOP‐NO group) or without NO (the VSOP group). Cold‐stored livers without WI served as controls. Liver viability was assessed after the preservation period by normothermic isolated reperfusion for 45 minutes with oxygenated Krebs‐Henseleit buffer. After 45 minutes of reperfusion, the VSOP‐NO–treated livers showed significantly lower alanine aminotransferase values than the WI‐damaged livers (10.2 ± 0.2 versus 78.2 ± 14.6 IU/L), whereas the control livers showed no differences from the VSOP‐NO–treated livers. The mitochondrial enzyme release was lower in the VSOP‐NO group (4.0 ± 0.7 IU/L) versus the WI group (18.2 ± 4.9 IU/L). An increased portal vein pressure was observed throughout reperfusion (45 minutes) in the WI group (21.7 ± 0.2 mm Hg) versus the VSOP‐NO group (12.2 ± 0.8 mm Hg) and the control group (19.9 ± 0.4 mm Hg). Furthermore, the NO concentration in the perfusate after 5 minutes of reperfusion was highest in the VSOP‐NO group. The release of malondialdehyde into the perfusate was significantly reduced in the VSOP‐NO group (0.9 ± 0.1 nmol/mL) versus the WI group (31.3 ± 5.3 nmol/mL). In conclusion, the resuscitation of livers after 30 minutes of WI to a level comparable to that of nonischemically damaged livers is possible with VSOP supplemented with NO gas. Moreover, the application of VSOP with NO minimizes the extent of injuries caused by oxygen free radicals during preservation. Liver Transpl 18:219–225, 2012.

A Novel Organ Preservation for Small Partial Liver Transplantations in Rats: Venous Systemic Oxygen Persufflation With Nitric Oxide Gas

The prognosis for recipients of small liver grafts is poor. The aim of this study was to determine the impact of venous systemic oxygen persufflation (VSOP) with nitric oxide (NO) gas for 30% partial liver preservation and transplantation in rats. After we determined optimal NO concentration as 40 ppm in vitro with the isolated perfused rat liver model, we assessed liver injury and regeneration in vivo at 1, 3, 24 and 168 h after transplantation in the following three groups after 3 h‐cold storage (n = 20 per group): control group = static storage; VSOP group = oxygen persufflation and VSOP+NO group = oxygen with NO persufflation. The liver graft persufflation was achieved with medical gas via the suprahepatic vena cava; In comparison with control group after transplantation, VSOP+NO preservation (1) increased portal circulation, (2) reduced AST and ALT release, (3) upregulated hepatic endothelial NO synthase, (4) reduced hepatocyte and bileductule damage and (5) improved liver regeneration. These results suggest that gaseous oxygen with NO persufflation is a novel and safe preservation method for small partial liver grafts, not only alleviating graft injury but also improve liver regeneration after transplantation.

Midkine promoter-based conditionally replicative adenovirus therapy for midkine-expressing human pancreatic cancer.

BackgroundTo develop a novel therapeutic strategy for human pancreatic cancer using a midkine promoter-based conditionally replicating adenovirus.MethodsWe examined midkine mRNA expression and midkine protein expression by seven human pancreatic cancer cell lines (AsPC-1, BxPC-3, CFPAC-1, HPAC, MIAPaCa-2, PANC-1, and Suit-2), as well as by non-cancerous pancreatic tissue and pancreatic cancers. Midkine promoter activity was measured in cancer cell lines by the dual luciferase reporter assay. Adenoviral transduction efficiency was assessed by fluorescent staining of cancer cell lines using adenovirus type 5 containing the green fluorescent protein gene (Ad5GFP). Replication of adenovirus type 5 containing the 0.6 kb midkne promoter (Ad5MK) was assessed by the detection of E1 protein in cancer cell lines. The cytotoxicity of Ad5MK for cancer cells was evaluated from the extent of growth inhibition after viral infection. Infection and replication were also assessed in nude mice with subcutaneous Suit-2 tumors by intratumoral injection of Ad5MK, Ad5GFP, or vehicle. E1a mRNA expression in the treated tumors and expression of the replication-specific adenoviral hexon protein were evaluated. Finally, the anti-tumor activity of Ad5MK against intraperitoneal xenografts of Suit-2 pancreatic cancer cells was examined after intraperitoneal injection of the virus.ResultsBoth midkine mRNA expression and midkine protein expression were strong in AsPC-1 and CFPAC-1 cell liens, moderate in BxPC-3, HPAC, and Suit-2 cell lines, and weak in PANC-1 and MIAPaCa-2 cell lines. Expression of midkine mRNA was significantly stronger in pancreatic cancers than in non-cancerous pancreatic tissues. The relative luciferase activity mediated by the 0.6 kb midkne fragment in AsPC-1, PANC-1, and Suit-2 cell lines was approximately 6 to 20 times greater than that in midkne-negative MIAPaCa-2 cell lines. Pancreatic cancer cell lines exhibited a heterogeneous adenoviral transduction profile. E1A expression was higher in cell lines with strong midkine expression than in cell lines with weak midkine expression. Ad5MK showed much greater cytotoxicity for midkine-expressing Suit-2 and PANC-1 cell lines than for midkine-negative MIAPaCa-2 cell lines. In the Suit-2 subcutaneous xenograft model, expression of E1A was detected in Ad5MK-treated tumors, but not in untreated and Ad5GFP-treated tumors. In the Suit-2 intraperitoneal xenograft model, the Ad5MK group survived for significantly longer than the Ad5GFP, PBS, and untreated groups.ConclusionAd5MK has an anti-tumor effect against human pancreatic cancer cell lines that express midkine mRNA. Midkine promoter-based conditionally replicative adenovirus might be a promising new gene therapy for pancreatic cancer.

Impact of oxygen free radicals in rat partial liver transplantation

BACKGROUND Due to the shortage of suitable organs, the demand for partial liver transplantation from living donors has increased worldwide. N-acetylcysteine (NAC) has shown protective effects as a free radical scavenger during hypothermic preservation and warm ischemia-reperfusion liver injury; however, no study has reported the effects in partial liver transplantation. The aim of this study was to analyze the impact of NAC on liver graft microcirculation and graft function after partial liver transplantation in rats. METHODS Orthotopic partial liver transplantations were performed in 40 rats following cold storage in histidine-tryptophan-ketoglutarate solution for 3 h with 20 mM NAC (NAC group, n = 20) or without (control group, n = 20). We assessed portal circulation, graft microcirculation, and biochemical analyses of plasma at 1, 3, 24, and 168 h after portal reperfusion. RESULTS (Control versus NAC, median and range): Portal venous pressure was significantly lower with NAC (P = 0.03). Microcirculation measured by laser Doppler was significantly improved with NAC throughout the time course (P = 0.003). Alanine aminotransferase levels were significantly lower in the NAC group (P < 0.05). Total antioxidative capacity was significantly higher in the NAC group at 1 h after reperfusion (Trolox equivalents: median, 3 μM; range, 2.9-6.7 versus median, 16.45 μM; range, 10.4-18.8). Lipid peroxidation was significantly abrogated in the NAC group (median, 177.6 nmol/mL; range, 75.9-398.1 versus median, 71.5 nmol/mL; range, 58.5-79 at 3 h). CONCLUSIONS This study showed that NAC treatment during cold storage resulted in improved microcirculation and preservation quality of partial liver graft likely because of enhanced antioxidant capacity and reduced lipid peroxidation.

Improving Research Practice in Rat Orthotopic and Partial Orthotopic Liver Transplantation: A Review, Recommendation, and Publication Guide

Background: Due to a worldwide shortage of donor organs for liver transplantation, alternative approaches, such as split and living donor liver transplantations, were introduced to increase the donor pool and reduce mortality on liver transplant waiting lists. Numerous details concerning the mechanisms and pathophysiology of liver regeneration, small-for-size syndrome, rejection, and tolerance in partial liver transplantation facilitated the development of various animal models. The high number of preclinical animal studies contributed enormously to our understanding of many clinical aspects of living donor and partial liver transplantations. Summary: Microsurgical rat models of partial orthotopic liver transplantation are well established and widely used. Nevertheless, several issues regarding this procedure are controversial, not clarified, or not yet properly standardized (graft rearterialization, size reduction techniques, etc.). The major aim of this literature review is to give the reader a current overview of rat orthotopic liver transplantation models with a special focus on partial liver transplantation. The aspects of model evolution, microsurgical training, and different technical problems are analyzed and discussed in detail. Our further aim in this paper is to elaborate a detailed publication guide in order to improve the quality of reporting in the field of rat liver transplantation according to the ARRIVE guidelines and the 3R principle. Key Messages: Partial orthotopic liver transplantation in rats is an indispensable, reliable, and cost-efficient model for transplantation research. A certain consensus on different technical issues and a significant improvement in scientific reporting are essential to improve transparency and comparability in this field as well as to foster refinement.

The distribution of atypical epithelium in main-duct type intraductal papillary mucinous neoplasms of the pancreas

Background/PurposeThe purpose of this study was to obtain the fundamental data necessary to discuss the appropriate operative mode for the resection of main-duct type intraductal papillary mucinous neoplasms (mIPMNs) of the pancreas.MethodsIn 23 patients who underwent total pancreatectomy with preoperative and postoperative diagnoses of mIPMN, the imaging studies and clinicopathological data were collected. The whole pancreatic specimen was histologically evaluated, and the distribution of atypical epithelium was mapped on a schema.ResultsPathological examination of the specimens revealed that 18 patients had carcinoma in the pancreas; 8 patients had invasive lesions and one patient had lymph node metastasis. Specimens from 5 patients did not bear carcinoma lesions but had widespread borderline lesions in the pancreas. The mapping of lesions in the pancreatic specimens revealed that, at least, borderline or higher lesions were present both in the head and distal pancreas in all patients. In the majority of the specimens, lesions from adenoma to carcinoma co-existed on the same slide, and there were normal cell intervals between the malignant lesions.ConclusionWe conclude that total pancreatectomy should be performed for mIPMN when dilatation of the main duct suggests possible spread of the lesion to the whole pancreas.