Tetsunosuke Shimizu

Deleterious Effect of CTLA4-Ig on a Treg-Dependent Transplant Model

Blockade of the B7:CD28 costimulatory pathway has emerged as a promising therapy to prevent allograft rejection. However, results from the belatacept phase III clinical trial demonstrated a higher rejection rate when compared to cyclosporine, raising concern about potential deleterious effects of this agent. In this study, we investigated the consequences of B7:CD28 blockade by hCTLA4Ig on regulator T cell (Treg) generation in different major histocompatibility complex (MHC) mismatch transplant models. Administration of hCTLA4Ig significantly decreased the amount of Tregs in B6 WT animals and this effect was predominant in thymus‐induced Tregs (Helios+). Although hCTLA4Ig prevented rejection in a fully allogeneic mismatch model, it accelerated rejection in a MHC class‐II mismatch model (MST = 26, p < 0.0001), in which long‐term allograft survival is dependent on Tregs. This accelerated rejection was associated with a marked reduction in thymus‐induced Tregs and led to a higher effector/regulatory T‐cell ratio in secondary lymphoid organs and in the allograft. This study confirms the importance of the B7:CD28 pathway in Treg homeostasis in an in vivo transplant model and suggests that hCTLA4Ig therapy may be deleterious in circumstances where engraftment is dependent on Tregs.

Impact of single-port cholecystectomy on postoperative pain.

This study compared postoperative pain following four‐port laparoscopic cholecystectomy (LC) and single‐port cholecystectomy (SPC).

Clinicopathological analysis of recurrence patterns and prognostic factors for survival after hepatectomy for colorectal liver metastasis

BackgroundHepatectomy is recommended as the most effective therapy for liver metastasis from colorectal cancer (CRCLM). It is crucial to elucidate the prognostic clinicopathological factors.MethodsEighty-three patients undergoing initial hepatectomy for CRCLM were retrospectively analyzed with respect to characteristics of primary colorectal and metastatic hepatic tumors, operation details and prognosis.ResultsThe overall 5-year survival rate after initial hepatectomy for CRCLM was 57.5%, and the median survival time was 25 months. Univariate analysis clarified that the significant prognostic factors for poor survival were depth of primary colorectal cancer (≥ serosal invasion), hepatic resection margin (< 5 mm), presence of portal vein invasion of CRCLM, and the presence of intra- and extrahepatic recurrence. Multivariate analysis indicated the presence of intra- and extrahepatic recurrence as independent predictive factors for poor prognosis. Risk factors for intrahepatic recurrence were resection margin (< 5 mm) of CRCLM, while no risk factors for extrahepatic recurrence were noted. In the subgroup with synchronous CRCLM, the combination of surgery and adjuvant chemotherapy controlled intrahepatic recurrence and improved the prognosis significantly.ConclusionsOptimal surgical strategies in conjunction with effective chemotherapeutic regimens need to be established in patients with risk factors for recurrence and poor outcomes as listed above.

A novel method using the VIO soft-coagulation system for liver resection

BACKGROUND The VIO soft-coagulation system (SCS) is a new device for tissue coagulation. The current study evaluated the efficacy of the SCS when used for liver resection. METHODS The 252 patients were divided into 2 groups; in 155 patients (conventional group), liver transection was performed using an ultrasonic dissector and saline-coupled bipolar electrocautery for hemostasis. In 97 patients (SCS group), the SCS was used instead of bipolar electrocautery. RESULTS The median blood loss and surgical time were less in the SCS group than in the conventional group (350 vs 640 mL, P = .0028; 280 vs 398 min, P < .0001). No significant differences were found in postoperative complications between the SCS group (32.0%) and the conventional group (40.6%). The risk factors for bleeding were nonuse of the SCS (P = .0039), macroscopic vascular invasion of the hepatic tumors (P = .0088), and collagen type IV value in the sera >200 (P = .0250) on multivariate analysis. In a subgroup analysis, in the collagen type IV value >200 subgroup, the tumor diameter >5 cm subgroup, and the inflow nonocclusion subgroup, use of the SCS decreased surgical bleeding (P = .0120, P = .0126, and P = .0032, respectively) and surgical time (P = .0001, P < .0001, and P = .0036, respectively) compared with the conventional group. Furthermore, even in the major hepatectomy group, the SCS use decreased surgical time (P < .0001). CONCLUSION The SCS is an effective and safe device for decreasing surgical time and surgical bleeding without increasing the rate of bile leakage and causing other complications.

Outcomes and predictors of microvascular invasion of solitary hepatocellular carcinoma

Microvascular invasion (MVI) is an important risk factor for early recurrence of hepatocellular carcinoma (HCC), but preoperative prediction of MVI is difficult.

Interruption of Dendritic Cell–Mediated TIM-4 Signaling Induces Regulatory T Cells and Promotes Skin Allograft Survival

Dendritic cells (DCs) are the central architects of the immune response, inducing inflammatory or tolerogenic immunity, dependent on their activation status. As such, DCs are highly attractive therapeutic targets and may hold the potential to control detrimental immune responses. TIM-4, expressed on APCs, has complex functions in vivo, acting both as a costimulatory molecule and a phosphatidylserine receptor. The effect of TIM-4 costimulation on T cell activation remains unclear. In this study, we demonstrate that Ab blockade of DC-expressed TIM-4 leads to increased induction of induced regulatory T cells (iTregs) from naive CD4+ T cells, both in vitro and in vivo. iTreg induction occurs through suppression of IL-4/STAT6/Gata3–induced Th2 differentiation. In addition, blockade of TIM-4 on previously activated DCs still leads to increased iTreg induction. iTregs induced under TIM-4 blockade have equivalent potency to control and, upon adoptive transfer, significantly prolong skin allograft survival in vivo. In RAG−/− recipients of skin allografts adoptively transferred with CD4+ T cells, we show that TIM-4 blockade in vivo is associated with a 3-fold prolongation in allograft survival. Furthermore, in this mouse model of skin transplantation, increased induction of allospecific iTregs and a reduction in T effector responses were observed, with decreased Th1 and Th2 responses. This enhanced allograft survival and protolerogenic skewing of the alloresponse is critically dependent on conversion of naive CD4+ to Tregs in vivo. Collectively, these studies identify blockade of DC-expressed TIM-4 as a novel strategy that holds the capacity to induce regulatory immunity in vivo.

Risk factors and patterns of early recurrence after curative hepatectomy for hepatocellular carcinoma

BACKGROUND Hepatocellular carcinoma (HCC) often recurs after curative hepatectomy; and early recurrence after hepatectomy (ERAH) is associated with poor prognosis. This study aimed to clarify risk factors and disease patterns for ERAH. METHODS We retrospectively analyzed clinicopathological factors of 232 patients who underwent initial curative hepatectomies for HCC between April 2000 and March 2013, and examined associated risk factors and early recurrence patterns by liver function status (as indicated by indocyanine green retention rate at 15 min [ICGR15]). RESULTS Patients who experienced recurrence within 6 months after hepatectomy (i.e., ERAH) had significantly shorter survival than those with longer disease-free intervals (P < 0.001). In multivariate analysis, microvascular invasion (mVI; P = 0.034) and ICGR15 ≥ 16% (P = 0.010) were independent risk factors for ERAH. In the ICGR1<16% subgroup, positive L3-AFP (P = 0.04), tumor size ≥ 5 cm (P = 0.011), surgical margin = 0 (P = 0.0103), mVI (P = 0.034), and extrahepatic recurrence were significant predictors of ERAH; in the ICGR15 ≥ 16%, subgroup, multiple tumors (P = 0.046) were identified as a risk factor for ERAH; however, this group did not experience much extrahepatic recurrence. CONCLUSIONS ERAH was associated with mVI and ICGR15 ≥ 16%. Recurrence patterns and risk factors vary by liver function status, which should be considered in forming management strategies for early recurrence of HCC after curative hepatectomy.

Salt Accelerates Allograft Rejection through Serum- and Glucocorticoid-Regulated Kinase-1–Dependent Inhibition of Regulatory T Cells

A high-salt diet (HSD) in humans is linked to a number of complications, including hypertension and cardiovascular events. Whether a HSD affects the immune response in transplantation is unknown. Using a murine transplantation model, we investigated the effect of NaCl on the alloimmune response in vitro and in vivo. Incremental NaCl concentrations in vitro augmented T cell proliferation in the settings of both polyclonal and allospecific stimulation. Feeding a HSD to C57BL/6 wild-type recipients of bm12 allografts led to accelerated cardiac allograft rejection, despite similar mean BP and serum sodium levels in HSD and normal salt diet (NSD) groups. The accelerated rejection was associated with a reduction in the proportion of CD4(+)Foxp3(+) regulatory T cells (Tregs) and a significant decrease in Treg proliferation, leading to an increased ratio of antigen-experienced CD4(+) T cells to Tregs in mice recipients of a HSD compared with mice recipients of a NSD. Because serum- and glucocorticoid-regulated kinase-1 (SGK1) has been proposed as a potential target of salt in immune cells, we fed a HSD to CD4(Cre)SGK1(fl/fl) B6-transplanted recipients and observed abrogation of the deleterious effect of a HSD in the absence of SGK1 on CD4(+) cells. In summary, we show that NaCl negatively affects the regulatory balance of T cells in transplantation and precipitates rejection in an SGK1-dependent manner.

Rejection of intradermally injected syngeneic tumor cells from mice by specific elimination of tumor-associated macrophages with liposome-encapsulated dichloromethylene diphosphonate, followed by induction of CD11b+/CCR3−/Gr-1− cells cytotoxic against the tumor cells

Tumor cell expansion relies on nutrient supply, and oxygen limitation is central in controlling neovascularization and tumor spread. Monocytes infiltrate into tumors from the circulation along defined chemotactic gradients, differentiate into tumor-associated macrophages (TAMs), and then accumulate in the hypoxic areas. Elevated TAM density in some regions or overall TAM numbers are correlated with increased tumor angiogenesis and a reduced host survival in the case of various types of tumors. To evaluate the role of TAMs in tumor growth, we here specifically eliminated TAMs by in vivo application of dichloromethylene diphosphonate (DMDP)-containing liposomes to mice bearing various types of tumors (e.g., B16 melanoma, KLN205 squamous cell carcinoma, and 3LL Lewis lung cancer), all of which grew in the dermis of syngeneic mouse skin. When DMDP-liposomes were injected into four spots to surround the tumor on day 0 or 5 after tumor injection and every third day thereafter, both the induction of TAMs and the tumor growth were suppressed in a dose-dependent and injection number-dependent manner; and unexpectedly, the tumor cells were rejected by 12 injections of three times-diluted DMDP-liposomes. The absence of TAMs in turn induced the invasion of inflammatory cells into or around the tumors; and the major population of effector cells cytotoxic against the target tumor cells were CD11b+ monocytic macrophages, but not CCR3+ eosinophils or Gr-1+ neutrophils. These results indicate that both the absence of TAMs and invasion of CD11b+ monocytic macrophages resulted in the tumor rejection.

Simultaneous laparoscopic resection of colorectal cancer and synchronous metastatic liver tumor.

Laparoscopic colorectal resection has been applied to advanced colorectal cancer. Synchronous liver metastasis of colorectal cancer would be treated safely and effectively by simultaneous laparoscopic colorectal and hepatic resection. Seven patients with colorectal cancer and synchronous liver metastasis treated by simultaneous laparoscopic resection were analyzed retrospectively. Three patients received a hybrid operation using a small skin incision, 2 patients underwent hand-assisted laparoscopic surgery using a small incision produced for colonic anastomosis, and 2 patients were treated with pure laparoscopic resection. The mean total operation duration was 407 minutes, and mean blood loss was 207 mL. Negative surgical margins were achieved in all cases. Mean postoperative hospital stay was 16.4 days. No recurrence at the surgical margin was observed in the liver. For selected patients with synchronous liver metastasis of colorectal cancer, simultaneous laparoscopic resection is useful for minimizing operative invasiveness while maintaining safety and curability, with satisfying short- and long-term results.