Platelet dynamics in the early phase of postischemic liver in vivo

BACKGROUND

In liver surgery, ischemia/reperfusion injury occasionally leads to liver failure by activating Kupffer cells (KCs) and leukocytes. However, few reports have demonstrated a relationship between KCs and platelets in vivo. This study investigated the relationship between these cells using intravital microscopy.

MATERIALS AND METHODS

Male Wistar rats were divided into two groups: (1) KC+ group, receiving 1 mL saline; and (2) KC- group, intravenously injected with liposome-encapsulated dichloromethylene disphosphonate for elimination of KCs. At 48 h after administration, 20 min of total normothermic hepatic ischemia was induced. Rhodamine-6G-labeled platelets and sinusoidal alterations were monitored using intravital microscopy up to 120 min after reperfusion. P-selectin, accumulated leukocytes and morphological damage, and alanine aminotransferase were evaluated.

RESULTS

In the KC+ group, numbers of adherent platelets increased significantly within 30 min after reperfusion. Endothelial cells of sinusoids in which KCs were mainly located were destroyed and the sinusoids were significantly constricted after reperfusion. Conversely, in the KC- group, adherent platelets in sinusoids were suppressed, and sinusoidal perfusion, endothelial cell damage and serum alanine aminotransferase levels were significantly improved. P-selectin on sinusoidal endothelial cells was not observed up to 120 min after reperfusion in either group.

CONCLUSIONS

Adherent platelets appear to reflect activation of KCs and lead to leukocyte accumulation, resulting in sinusoidal perfusion disturbance and liver failure. Evaluation of adherent platelets in the microcirculation offers an important marker of hepatic injury.

Portal vein reconstruction using a left renal vein graft for a patient with hilar cholangiocarcinoma

We report a patient with hilar cholangiocarcinoma who underwent combined portal vein reconstruction using a left renal vein graft. A 68-year-old man was referred to the hospital with a one-week history of dark urine and jaundice. Cholangiography through the percutaneous transhepatic biliary drainage catheter and magnetic resonance cholangiopancreatography demonstrated complete obstruction of the hepatic primary confluence extended to the left secondary confluence. The patient underwent left hepatic lobectomy combined with total caudate lobectomy and extrahepatic bile duct resection. At operation, carcinoma invasion was observed from the portal trunk to the right portal branch. So, combined portal vein resection and graft interpose using left renal vein was performed. The caliber of left renal vein was wider than the right portal branch. No remarkable renal and hepatic dysfunction occurred postoperatively. In conclusion, left renal vein seems appropriate as an autograft when reconstructing the portal vein, especially main portal trunk, in patients with advanced hepatobiliary malignancies. It may be necessary to adjust the caliber when anastomosing the left renal vein to the right or left portal branch because the diameter of the left renal vein is usually wide.

[A case of recurrent biliary tract cancer with peritoneal dissemination treated with intraperitoneal chemotherapy]

We report a case of postoperative dissemination of intrahepatic biliary tract cancer subsequently treated with intraperitoneal chemotherapy combined with systemic chemotherapy. A 61-year-old-woman who underwent hepatic resection 18 months before was admitted for abdominal distension. CT scan revealed a recurrent tumor in her transverse mesocolon. We tried tumor resection but peritoneal dissemination was recognized, and intraperitoneal chemotherapy was started followed by systemic hemotherapy. For 34 months after the diagnosis of postoperative peritoneal dissemination, the patient has not suffered from abdominal distension and stenosis of the gastrointestinal tract. The CA19-9 level remained low for over 30 months. Intraperitoneal chemotherapy followed by systemic chemotherapy in this case seemed to delay the progression of disseminated tumor and to preserve the quality of life of the patient. The present case shows the effectiveness of intraperitoneal chemotherapy with or followed by systemic chemotherapy for patients who had peritoneal disseminations.

Platelets promote liver regeneration in early period after hepatectomy in mice

BACKGROUND

Platelets contain several growth factors, including platelet-derived growth factor and hepatocyte growth factor.

MATERIALS AND METHODS

We examined the effects of platelet increment on liver regeneration after 70% hepatectomy. Hepatectomies were carried out in male BALB/c mice, and subsequently divided into three groups: (i) untreated mice, (ii) thrombocytotic mice induced with thrombopoietin, and (iii) thrombocytopenic mice induced with anti-platelet antibody. Growth kinetics in the liver were analyzed as a function of the liver/body weight ratio, the mitotic index, the proliferating cell nuclear antigen labeling index and Ki-67 labeling index. Activation of signal transduction pathways relating to cell proliferation were examined, including the STAT3, Akt, and ERK1/2 pathways. Platelet accumulation in the residual liver was quantified by immunohistochemistry and transmission electron microscopy.

RESULTS

In thrombocytotic and thrombocytopenic mice, liver/body weight ratios and Ki-67 labeling indices were significantly increased and significantly decreased, respectively, compared with untreated mice 48 hours post-hepatectomy. The Akt pathway was strongly activated, and platelet accumulation was significantly increased in thrombocytotic group 5 minutes post-hepatectomy compared with normal and thrombocytopenic groups. After hepatectomy platelets accumulated in the sinusoids of liver and promoted hepatocyte proliferation in early period after hepatectomy.

CONCLUSION

By increasing or decreasing the platelet, marked changes in liver regeneration can occur, due to differences in cellular signaling and mitosis.

Freeze-dried platelets promote hepatocyte proliferation in mice

In recent years, platelets are reported to promote liver, as well as bone regeneration and dermal wound healing. Platelets are required not only for thrombocytopenia treating but also for regenerative therapy. Platelets cannot be stored beyond three days, therefore, shortage of fresh platelets sometimes occurs. To preserve platelets for a long duration without degrading growth factors, a freeze-dried technique is required. We report here that platelets can be preserved by freeze-drying, using a programmed freezing method to avoid intracellular ice crystal formation. Freeze-dried platelets kept their morphological countenance and response with the agonist of thrombin was well maintained. Freeze-dried platelets stored adenine nucleotides, PDGF, and IGF-1 the same as those of fresh platelets. Freeze dried platelets also preserved their proliferative effect on hepatocytes identical to that of fresh platelets. These results of our study suggest that freeze dried platelets will obviate the storage problem of fresh platelets.

Platelets Strongly Induce Hepatocyte Proliferation with IGF-1 and HGF In Vitro

BACKGROUND

It is well known that platelets have a thrombotic effect. However, platelets play an important role not only in hemostasis but also in wound healing and tissue regeneration. Platelets have been reported to accumulate in the liver and promote liver regeneration after an extended hepatectomy, but the mechanism is unclear. The present study was designed to clarify the mechanism by which platelets have a direct proliferative effect on hepatocytes in vitro.

MATERIALS AND METHODS

Hepatocytes obtained from male BALB/c mice by collagenase digestion and immortalized hepatocytes (TLR2) were used. To elucidate the mechanism of the proliferative effect of platelets, DNA synthesis of hepatocytes was measured under various conditions and the related cellular signals were analyzed. Chromatographic analysis was also performed to clarify which elements of platelets have mitogenic activity.

RESULTS

DNA synthesis significantly increased in the hepatocytes cultured with platelets (P < 0.001). However, when the platelets and hepatocytes were separated, the platelets did not have a proliferative effect. Whole disrupted platelets, the supernatant fraction, and fresh isolated platelets had a similar proliferative effect, while the membrane fraction did not. After the addition of platelets, both Akt and extracellular signal-regulated kinases ERK1/2 were activated, but extracellular signal-regulated kinase STAT3 was not activated. Some mitogenic fractions were obtained from the platelet extracts by gel exclusion chromatography; the fractions were rich in hepatocyte growth factor and IGF-1.

CONCLUSIONS

Direct contact between platelets and hepatocytes was necessary for the proliferative effect. The direct contact initiated signal transduction involved in growth factor activation. Hepatocyte growth factor, vascular endothelial growth factor, and insulin-like growth factor-1, rather than platelet-derived growth factor, mainly contributed to hepatocyte proliferation.

Significance of ductal margin status in patients undergoing surgical resection for extrahepatic cholangiocarcinoma

OBJECTIVES

The objective of this study was to determine whether carcinoma in situ at the bile duct margin is prognostically different from residual invasive carcinoma in patients with extrahepatic cholangiocarcinoma. Although there are many reports that the ductal margin status at bile duct resection stumps is a prognostic indicator in patients with extrahepatic cholangiocarcinoma, some patients who undergo resection with microscopic tumor involvement of the bile duct margin survive longer than expected.

METHODS

A retrospective clinicopathological analysis of 128 patients who had undergone surgical resection for extrahepatic cholangiocarcinoma was conducted. The status of the bile duct resection margin was classified as negative in 105 patients (82.0%), positive for carcinoma in situ in 12 patients (9.4%), and positive for invasive carcinoma in 11 patients (8.6%).

RESULTS

Ductal margin status was an independent prognostic indicator by both univariate (p = 0.0022) and multivariate (p = 0.0105) analyses, along with lymph node metastasis. There was no significant difference between patients with a negative ductal margin and those with a positive ductal margin with carcinoma in situ (p = 0.5247). The 5-year survival rate of patients with a positive ductal margin with carcinoma in situ (22.2%) was significantly better (p = 0.0241) than with invasive carcinoma (0%). There was a significant relationship between local recurrence and ductal margin status (p = 0.0401).

CONCLUSIONS

Among patients undergoing surgical resection for extrahepatic cholangiocarcinoma, invasive carcinoma at the ductal resection margins appears to have a significant relation to local recurrence and also a significant negative impact on survival, whereas residual carcinoma in situ does not. Discrimination whether carcinoma in situ or invasive carcinoma is present is important in clinical setting in which the resection margin at the ductal stump is positive.

Mechanism of NKT cell-mediated transplant tolerance

The mechanism by which CD1d-restricted Valpha14 natural killer T (NKT) cells participate in transplant tolerance has yet to be completely clarified. Recently, we showed that repeated activation of NKT cells by their specific glycolipid ligand, alpha-galactosylceramide, leads to a change in function to an immune regulatory role with IL-10 production. Moreover, these cells were shown to be able to induce regulatory dendritic cells (DCs). In this study, we showed that NKT cells from transplant tolerant recipients of cardiac allograft produced higher levels of IL-10, which is required for the maintenance of tolerance; this was proved by adoptive transfer experiments. In addition, DCs from wild-type (WT) tolerant recipients but not NKT cell-deficient recipients showed a higher IL-10-producing profile, a more immature phenotype, and tolerogenic capability. CD4 T cells from WT tolerant recipients but not NKT cell-deficient recipients also produced higher levels of IL-10 upon alloantigen stimulation and showed lower proliferative activity that was reversed by blocking the IL-10 receptor. These data indicate the existence of IL-10-dependent immune regulatory interplay among NKT cells, DCs, and CD4 T cells, even in the absence of artificial stimulation of NKT cells with synthetic glicolipids, which is required for the maintenance of transplant tolerance.

Early Postoperative Oral Feeding Accelerates Upper Gastrointestinal Anastomotic Healing in the Rat Model

BACKGROUND

The benefits of early postoperative oral feeding following colonic anastomosis have previously been demonstrated. However, early postoperative oral feeding in patients with upper gastrointestinal surgery has been avoided because of concerns regarding anastomotic leakage. We investigated whether early postoperative oral feeding was advantageous for upper gastrointestinal anastomosis in comparison to parenteral feeding with a fasting period.

MATERIALS AND METHODS

Male Sprague-Dawley rats were subjected to the same surgical manipulation, i.e., venous catheterization, gastrostomy, and proximal jejunal anastomosis. Rats were divided into two groups: the enteral nutrition (EN) group, which received nutrients via gastrostomy as a substitute for oral feeding, and the total parental nutrition (TPN) group, which was fed via a venous catheter. Identical nutritional solutions were administered to the two groups immediately after surgery. The anastomotic bursting pressure (ABP) and the content of hydroxyproline in the anastomotic tissue were measured 5 days postoperatively.

RESULTS

The ABP in the EN group was significantly higher than that in the TPN group (214.6 +/- 42 versus 149.5 +/- 49 mmHg; p < 0.01). The hydroxyproline content in the EN group was also significantly higher (63.5 +/- 10 versus 50.5 +/- 12 micromol/g dry tissue; p < 0.01).

CONCLUSIONS

Early enteral feeding via gastrostomy accelerated jejunal anastomotic healing in comparison to parenteral feeding. This study clearly indicates that early oral feeding after upper gastrointestinal surgery leads to prompt anastomotic healing.

Effect of portocaval shunt on residual extreme small liver after extended hepatectomy in porcine

BACKGROUND

When residual liver volume is extremely small after extended hepatectomy, postoperative hepatic failure may ensue. The cause of the hepatic failure is likely associated with the portal hypertension after hepatectomy. We investigated the effects of portocaval shunt on portal hypertension in producing sinusoidal microcirculatory injury after extended hepatectomy in pigs.

METHODS

Fourteen pigs were divided into two groups: a group without a shunt, in which extended hepatectomy was carried out (i.e., residual volume was 17% of the whole liver), and a group with a shunt, in which extended hepatectomy was carried out and a portocaval shunt was inserted. The portocaval shunt was placed by side-to-side anastomosis between the portal vein and the inferior vena cava.

RESULTS

In the group without a shunt, all pigs died of hepatic failure within postoperative day 3. In the group with a shunt, all pigs were alive for more than 4 days, and 4 pigs survived longer than 7 days. Portal vein pressure after hepatectomy was 15.9 +/- 3.8 mmHg in the group without a shunt and 10.5 +/- 0.6 mmHg in the group with a shunt (P < 0.01). The portal vein flow after 83% hepatectomy in the group without a shunt increased significantly more than at laparotomy and in the group with a shunt (P < 0.01). In the group without a shunt, remarkable destruction of the sinusoidal lining and edema of the portal triad and hydropic change of hepatocytes were observed 1 hour after hepatectomy, but these findings were not observed in the group with a shunt.

CONCLUSIONS

These results indicate that, after extended hepatectomy, overload of portal flow is one of the most significant risk factors of hepatic failure by sinusoidal microcirculatory injury.

Dual assemblies of an activating immune receptor, MAIR-II, with ITAM-bearing adapters DAP12 and FcRgamma chain on peritoneal macrophages

Certain activating immune receptors expressed on myeloid cells noncovalently associate with either DAP12 or FcepsilonRIgamma (FcRgamma chain), the ITAM-bearing transmembrane adapter proteins. An activating receptor, myeloid-associated Ig-like receptor (MAIR) II, is expressed on a subset of B cells and macrophages in the spleen and peritoneal cavity of mice and associates with DAP12 in these cells. However, we demonstrate here that cross-linking MAIR-II with mAb induced secretion of a significant amount of the inflammatory cytokines TNF-alpha and IL-6 from DAP12(-/-) as well as wild-type (WT) peritoneal macrophages. We show that MAIR-II associates with not only DAP12 but also FcRgamma chain homodimers in peritoneal macrophages. LPS enhanced the FcRgamma chain expression and FcRgamma chain-dependent cell surface expression of MAIR-II and had additive effects on MAIR-II-mediated inflammatory cytokine secretion from peritoneal macrophages. The lysine residue in the transmembrane region of MAIR-II was involved in the association with FcRgamma chain as well as DAP12. Our findings present the first case of an activating receptor that uses either DAP12 or FcRgamma chain as a signaling adapter. The FcRgamma chain may provide cooperation with and/or compensation for DAP12 in MAIR-II-mediated inflammatory responses by peritoneal macrophages.

Isolation of mouse pancreatic ductal progenitor cells expressing CD133 and c-Met by flow cytometric cell sorting

BACKGROUND & AIMS

Islet transplantation has become available across the globe since a novel protocol was reported. However, because donors are in short supply, only a minority of patients benefit from this procedure. Pancreatic progenitor cells are a promising resource for regeneration of new islets, but whether progenitor cells reside in ductal epithelium is not clear.

METHODS

Mouse pancreas was examined by immunohistochemistry with cell surface markers specific for ductal cells. We developed an isolation method for ductal cells by flow cytometric cell sorting using a newly identified specific marker for ductal cells. By using an in vitro colony assay, we characterized their proliferative and multipotent capacity.

RESULTS

CD133 is expressed specifically in ductal epithelium. Flow cytometric analysis revealed that purified ductal cells are highly enriched in the CD133(+)CD34(-)CD45(-)Ter119(-) fraction. An analysis of clonal epithelial colonies formed by individual cells revealed that progenitor cells with multilineage differentiation capacity are present in neonatal ductal epithelium. Moreover, these progenitor cells express c-Met. In adult mice, progenitor cells that show a high proliferative capacity but appear committed to a ductal lineage are co-purified with CD133(+)CD34(-)CD45(-)Ter119(-) cells.

CONCLUSIONS

We established a system for isolating and culturing mouse pancreatic ductal cells that relies on flow cytometric cell sorting. Clonal analysis revealed that a population of progenitor cells is present among CD133(+) ductal cells. Isolation of these cells will facilitate future studies into the roles of pancreatic progenitor cells in regeneration and carcinogenesis.

Consistent liver metastases in a rat model by portal injection of microencapsulated cancer cells

Consistent liver metastases in animal models is generally observed only with certain cancer cell lines. With the aim of improving on existing animal models of liver metastases, we hypothesized that cancer cells encased in 300 microm microcapsules, mimicking micrometastatic foci, might be effective seeds of liver metastases. A total of 3,000 microcapsules, containing 700 to 1,500 viable cells/capsule in logarithmic growth phase of three human pancreatic cancer cell lines (SUIT-2, AsPC-1, and BxPC-3), were transplanted in nude rats by portal injection. The rate of liver metastases was 100% (12 of 12), 100% (6 of 6), and 83% (5 of 6) for SUIT-2, AsPC-1, and BxPC-3 microcapsules, respectively. In contrast, the administration of an identical number of single cancer cells (2.1-4.5 x 10(6)) did not lead to liver metastases. Metastases was strictly limited to the liver, was quite stable, and could be proportionately tailored by varying the number of cancer microcapsules administered. Microscopic observation showed that two-thirds of the cancer microcapsules were lodged in the peripheral small (20-50 microm) portal veins, although one-third of the cancer microcapsules were trapped in the central wide (200-400 microm) portal vein. Capsules began to burst at day 3, with recognizable metastases produced at day 7, resulting in overt metastases production at days 28 to 42. The present cancer microcapsule method may be useful for obtaining liver metastases in animal models, especially for cell lines that will not form liver metastases with conventional single cell injection methods and/or for experiments requiring the consistent formation of liver metastases.

[Informed consent for patients with pancreatic cancer]

Pancreatic cancer is an intractable malignancy with the poorest prognosis among digestive tract cancers. It is important when we obtain informed consent (IC) from patients with pancreatic cancer and their families to convey sufficiently that pancreatic cancer is intractable and provide support to help patients maintain a positive attitude toward treatment. Although the efficacy of chemo (radiation) therapy in pancreatic cancer is still unclear, the progress of various clinical trials on postoperative adjuvant therapy centered on gemcitabine hydrochloride, and chemo (radiation) therapy for unresectable tumors has raised expectations in recent years. To enable each individual patient to select the optimal treatment based on his or her personal outlook on life, it is important to obtain IC in good faith through the accurate diagnosis of pancreatic cancer and the use of the latest treatment information.

Establishment of an Animal Model With Side Effects Induced by Mycophenolate Mofetil and Pharmacohistological Analysis of Them

Mycophenolate mofetil (MMF) is used for immunosuppression after organ transplantation, but gastrointestinal side effects including diarrhea are sometimes observed with this drug. We sought to construct on animal model of diarrhea with MMF in rodents.

MATERIALS AND METHODS

BALB/Cj mice, weighing 25 g received 500 mg /kg of MMF, 60 mg/kg of levofloxacin (LVFX), 1000 mg/kg of Hangeshashin-to (HST), which is traditional Kampo medicine. This cocktail was administered orally to MMF, LVFX, HST, MMF+LVFX, and MMF+LVFX+HST groups for 21 days. We measured the water content fecal collected on days 1, 4, 8, 11, 14, 18, and 21. Feces on day 21 were cultured for identification of fecal flora. Mice were sacrificed on day 21, with blood samples collected to measure mycophenolic acid (MPA) concentrations by HPLC. Jejunum, cecum, and colon were taken for histological evaluation.

RESULTS

Significant weight loss of mice and increased fecal water content of were observed in MMF and MMF+LVFX but not in MMF+LVFX+HST groups. Serum MPA levels didn't differ in MMF-administered groups. Inflammatory changes in intestinal villi were observed in the cecum in MMF and MMF+LVFX groups. A change in fecal flora was observed in LVFX-administered groups.

CONCLUSION

Diarrhea induced by MMF in a rodent model produced inflammatory changes in the cecum. LVFX seemed to change the activity of beta-glucuronidase in the fecal flora. HST suppressed fecal softening induced by MMF in this animal model.

Microfabricated airflow nozzle for microencapsulation of living cells into 150 micrometer microcapsules

Microencapsulation of genetically engineered cells has attracted much attention as an alternative nonviral strategy to gene therapy. Though smaller microcapsules (i.e. less than 300 microm) theoretically have various advantages, technical limitations made it difficult to prove this notion. We have developed a novel microfabricated device, namely a micro-airflow-nozzle (MAN), to produce 100 to 300 microm alginate microcapsules with a narrow size distribution. The MAN is composed of a nozzle with a 60 microm internal diameter for an alginate solution channel and airflow channels next to the nozzle. An alginate solution extruded through the nozzle was sheared by the airflow. The resulting alginate droplets fell directly into a CaCl2 solution, and calcium alginate beads were formed. The device enabled us to successfully encapsulate living cells into 150 microm microcapsules, as well as control microcapsule size by simply changing the airflow rate. The encapsulated cells had a higher growth rate and greater secretion activity of marker protein in 150 microm microcapsules compared to larger microcapsules prepared by conventional methods because of their high diffusion efficiency and effective scaffold surface area. The advantages of smaller microcapsules offer new prospects for the advancement of microencapsulation technology.

[A case of stage IVA intrahepatic biliary tract cancer successfully treated with gemcitabine]

We reported a case of non-resectable intrahepatic biliary tract cancer, treated with Gemcitabine and oral anticancer drugs. A 45-year-old man was admitted to the hospital due to abdominal distension and fatigue. CT scan revealed intrahepatic biliary tract cancer in the left lobe, which had metastasized to both lobes. Based on the diagnosis of non-resectable intrahepatic biliary tract cancer, systemic chemotherapy using gemcitabine (GEM) was employed. One course of the treatment consisted of 4 weeks. GEM 1,000 mg was administered once a week for 3 weeks followed by a week of no treatment. At the same time, the oral anti-cancer drug (5'-DFUR 600 mg/day) was administered every day. After 4 courses of chemotherapy, both the primary tumor and the hepatic metastasis were diminished, and the serum level of CA19-9 was reduced to the normal value. Relief from the abdominal distension allowed the patient to return to work. The chemotherapy was continued by outpatient-clinic treatment, preserving the quality of life for 13 months. The present case shows that gemcitabine/5'-DFUR combination is well supported in advanced unresectable biliary tract cancer.

A long-term survivor of repeated inguinal nodes recurrence of papillary serous adenocarcinoma of CUP: case report

BACKGROUND

Tumor spread beyond the peritoneal cavity in cases of papillary serous adenocarcinoma of the unknown primary (CUP) is a rare late event and carries a poor prognosis.

CASE PRESENTATION

A 71-year-old female was referred to our hospital because of a large right inguinal tumor with biopsy evidence of carcinoma as well as an elevated serum CA125 (cancer antigen 125). She underwent complete resection of the right inguinal tumor and multiple pelvic tumors, which involved the rectum, ovary and uterus. Pathological examination revealed the tumors to be metastases of a papillary serous adenocarcinoma with a psammoma body of CUP. On the 28th postoperative day, newly developed asymptomatic small left inguinal node metastases in the setting of a normal CA125 level were removed. Four and a half years after the primary resection, the CA125 level increased again and newly developed asymptomatic metastases were found in the right deep inguinal nodes and extirpated at that time. All surgical resections followed the modified FAM (5FU, Adriamycin; ADM, MMC) regimen, including protracted dairy oral administration of UFT or 5'-FDUR, Cimetidine and PSK (protein-bound polysaccharide K) as an immunomodulator or biological response modifier in conjunction with intermittent one-day continuous infusion (ADM+MMC) or intermittent single bolus injection of ADM+MMC. At present, the patient has been living in good health for almost 7 years with no evidence of relapse.

CONCLUSION

Aggressive resection surgery followed by effective adjuvant chemotherapy is necessary for surviving long time without relapse of poorly prognostic patients with metastases outside of the abdominal cavity from peritoneal papillary serous adenocarcinomas.

The importance of CD25+ CD4+ regulatory T cells in mouse hepatic allograft tolerance

In mouse liver transplantation, tolerance is readily inducible. Recent studies have revealed that CD25+ CD4+ regulatory T cells play an important role in regulating various immune responses, including transplant tolerance. However, the contribution of these cells to tolerance in mouse liver transplantation has not been elucidated. We showed here that depletion of CD25+ CD4+ T cells increased proliferative response of CD4+ T cells and cytotoxic T lymphocyte induction of CD8+ T cells. Depletion of these cells in the recipient but not in the donor before liver transplantation caused rejection. Furthermore, the number of CD25+ CD4+ population and forkhead/winged helix transcription factor expression in liver mononuclear lymphocytes derived from tolerant mice were higher than those from grafts undergoing rejection. In conclusion, these results indicate that CD25+ CD4+ regulatory T cells in the recipient but not in the donor of liver transplantation are important for the tolerance induction.

Excessive portal flow causes graft failure in extremely small-for-size liver transplantation in pigs

AIM

To evaluate the effects of a portocaval shunt on the decrease of excessive portal flow for the prevention of sinusoidal microcirculatory injury in extremely small-for-size liver transplantation in pigs.

METHODS

The right lateral lobe of pigs, i.e. the 25% of the liver, was transplanted orthotopically. The pigs were divided into two groups: graft without portocaval shunt (n = 11) and graft with portocaval shunt (n = 11). Survival rate, portal flow, hepatic arterial flow, and histological findings were investigated.

RESULTS

In the group without portocaval shunt, all pigs except one died of liver dysfunction within 24 h after transplantation. In the group with portocaval shunt, eight pigs survived for more than 4 d. The portal flow volumes before and after transplantation in the group without portocaval shunt were 118.2+/-26.9 mL/min/100 g liver tissue and 270.5+/-72.9 mL/min/100 g liver tissue, respectively. On the other hand, in the group with portocaval shunt, those volumes were 124.2+/-27.8 mL/min/100 g liver tissue and 42.7+/-32.3 mL/min/100 g liver tissue, respectively (P<0.01). As for histological findings in the group without portocaval shunt, destruction of the sinusoidal lining and bleeding in the peri-portal areas were observed after reperfusion, but these findings were not recognized in the group with portocaval shunt.

CONCLUSION

These results suggest that excessive portal flow is attributed to post transplant liver dysfunction after extreme small-for-size liver transplantation caused by sinusoidal microcirculatory injury.

Antithrombin reduces reperfusion-induced hepatic metastasis of colon cancer cells

AIM: To examine whether antithrombin (AT) could prevent hepatic ischemia/reperfusion (I/R)-induced hepatic metastasis by inhibiting tumor necrosis factor (TNF)-α-induced expression of E-selectin in rats.

METHODS: Hepatic I/R was induced in rats and mice by clamping the left branches of the portal vein and the hepatic artery. Cancer cells were injected intrasplenically. The number of metastatic nodules was counted on day 7 after I/R. TNF-α and E-selectin mRNA in hepatic tissue, serum fibrinogen degradation products and hepatic tissue levels of 6-keto-PGF_1α, a stable metabolite of PGI₂, were measured.

RESULTS: AT inhibited increases in hepatic metastasis of tumor cells and hepatic tissue mRNA levels of TNF-α and E-selectin in animals subjected to hepatic I/R. Argatroban, a thrombin inhibitor, did not suppress any of these changes. Both AT and argatroban inhibited I/R-induced coagulation abnormalities. I/R-induced increases of hepatic tissue levels of 6-keto-PGF_1α were significantly enhanced by AT. Pretreatment with indomethacin completely reversed the effects of AT. Administration of OP-2507, a stable PGI₂ analog, showed effects similar to those of AT in this model. Hepatic metastasis in congenital AT-deficient mice subjected to hepatic I/R was significantly increased compared to that observed in wild-type mice. Administration of AT significantly reduced the number of hepatic metastases in congenital AT-deficient mice.

CONCLUSION: AT might reduce I/R-induced hepatic metastasis of colon cancer cells by inhibiting TNF-α-induced expression of E-selectin through an increase in the endothelial production of PGI₂. These findings also raise the possibility that AT might prevent hepatic metastasis of tumor cells if administered during the resection of liver tumors.

Detection of hepatic metastases using ferucarbotran-enhanced MR imaging: Feasibility and diagnostic accuracy of three-dimensional sensitivity-encoding water-excitation multishot echo-planar sequence (3D-SWEEP)

PURPOSE

To evaluate the diagnostic accuracy of a ferucarbotran-enhanced three-dimensional sensitivity-encoding water-excitation multishot echo-planar sequence (3D-SWEEP) for detecting hepatic metastases compared to a T2*-weighted fast field-echo (FFE) sequence.

MATERIALS AND METHODS

Twenty-five consecutive patients with hepatic metastases underwent ferucarbotran-enhanced MRI on a 1.5-T unit before hepatic resections. Eighty-two foci of metastases were confirmed by histopathology or intraoperative ultrasonography (US). Signal-intensity decay (SID), tumor-to-liver contrast (TLC), and image quality were compared between T2*-weighted FFE and 3D-SWEEP. Three independent observers reviewed three imaging sets: set 1, without 3D-SWEEP or T2*-weighted FFE; set 2, with T2*-weighted FFE; and set 3, with 3D-SWEEP. The mean values of areas under alternative free response receiver operating characteristic curves (Az) and sensitivities were compared among the three sets.

RESULTS

SID and TLC were significantly greater for 3D-SWEEP than T2*-weighted FFE, although 3D-SWEEP had poorer image quality. The mean Az and sensitivity were significantly greater for set 3 compared to set 1 for detecting overall lesions, and compared to sets 1 and 2 for detecting lesions of 1-2 cm in diameter.

CONCLUSION

Despite relatively prominent artifacts, ferucarbotran-enhanced 3D-SWEEP was more sensitive and accurate than T2*-weighted FFE for detecting hepatic metastases.