Takehiko Hanaki

The estrogen receptor β-PI3K/Akt pathway mediates the cytoprotective effects of tocotrienol in a cellular Parkinson's disease model.

Tocotrienols (T3s) are members of the vitamin E family, have antioxidant properties, and are promising candidates for neuroprotection in the pathogenesis of neurodegenerative disorders such as Parkinsons disease (PD). However, whether their antioxidant capacities are required for their cytoprotective activity remains unclear. In this regard, the antioxidant-independent cytoprotective activity of T3s has received considerable attention. Here, we investigated the signaling pathways that are induced during T3-dependent cytoprotection of human neuroblastoma SH-SY5Y cells, as these cells are used to model certain elements of PD. T3s were cytoprotective against 1-methyl-4-phenylpyridinium ion (MPP(+)) and other PD-related toxicities. γT3 and δT3 treatments led to marked activation of the PI3K/Akt signaling pathway. Furthermore, we identified estrogen receptor (ER) β as an upstream mediator of PI3K/Akt signaling following γT3/δT3 stimulation. Highly purified γT3/δT3 bound to ERβ directly in vitro, and knockdown of ERβ in SH-SY5Y cells abrogated both γT3/δT3-dependent cytoprotection and Akt phosphorylation. Since membrane-bound ERβ was important for the signal-related cytoprotective effects of γT3/δT3, we investigated receptor-mediated caveola formation as a candidate for the early events of signal transduction. Knockdown of caveolin-1 and/or caveolin-2 prevented the cytoprotective effects of γT3/δT3, but did not affect Akt phosphorylation. This finding suggests that T3s and, in particular, γT3/δT3, exhibit not only antioxidant effects but also a receptor signal-mediated protective action following ERβ/PI3K/Akt signaling. Furthermore, receptor-mediated caveola formation is an important event during the early steps following T3 treatment.

Nicotine enhances the malignant potential of human pancreatic cancer cells via activation of atypical protein kinase C

BACKGROUND Pancreatic cancer (PC) is the most lethal malignancy among solid tumors, and the most common risk factor for its development is cigarette smoking. Atypical protein kinase C (aPKC) isozymes function in cell polarity, proliferation, and survival, and have also been implicated in carcinogenesis. However, the involvement of aPKC in PC progression and the effect of nicotine, a major component of cigarette smoke, on the biological activities of aPKC remain to be fully elucidated. METHODS We investigated the effects of nicotine on the proliferation, migration and invasion of the human PC cell lines Panc1 and BxPC3. We analyzed aPKC localization and activity by immunohistochemistry and in vitro kinase assays, respectively, to assess their involvement in the regulation of PC progression. Moreover, we examined the effect of nicotine on implanted peritoneal tumors of PC cells in mice. RESULTS Nicotine enhanced cell proliferation, migration and invasion in Panc1 and BxPC3 cells. In nicotine-treated PC cells, the aPKC was significantly activated. We also found that nicotine induced phosphatidylinositol 3-kinase (PI3K) signal activation, and a specific inhibitor of the nicotine acetylcholine receptor (nAChR) as well as knockdown of nAChR prevented nicotine-mediated Akt phosphorylation and aPKC activation. In a peritoneal dissemination model of PC, nicotine-treated mice had larger tumors and increased numbers of nodules. Immunohistochemistry showed enhanced expression levels of aPKC and phosphorylated Akt in nodules from nicotine-treated mice. CONCLUSIONS AND GENERAL SIGNIFICANCE Nicotine induces aberrant activation of aPKC via nAChR/PI3K signaling in PC cells, resulting in enhancement of cellular proliferation, migration and invasion.

Estrogen receptor-mediated effect of δ-tocotrienol prevents neurotoxicity and motor deficit in the MPTP mouse model of Parkinson's disease.

Neuroprotection following signal transduction has been investigated recently as a strategy for Parkinsons disease (PD) therapy. While oxidative stress is important in the pathogenesis of PD, neuroprotection using antioxidants such as α-tocopherol have not been successful. δ-tocotrienol (δT3), a member of the vitamin E family, has received attention because of activities other than its antioxidative effects. In the present study, we examined the estrogen receptor-β (ERβ)-mediated neuroprotective effects of δT3 in a mouse model of PD. ERβ is expressed in neuronal cells, including dopaminergic neurons in the substantia nigra. Daily forced oral administration of δT3 inhibited the loss of dopaminergic neurons in the substantia nigra. In addition, the ER inhibitor tamoxifen canceled the neuroprotective effects of δT3. Moreover, δT3 administration improved the performance of the PD mice in the wheel running activity, while tamoxifen inhibited this improved performance. These results suggest that the oral administration of δT3 may be useful in the treatment of PD patients, and ERβ may be a candidate target for the neuroprotection activity of δT3.

The attenuation value of preoperative computed tomography as a novel predictor for pancreatic fistula after pancreaticoduodenectomy

PurposePancreatic fistula (PF) is the most serious complication following pancreaticoduodenectomy (PD). This study was performed to identify new clinical factors that may predict the development of PF after PD to improve perioperative management.MethodsSeventy-five consecutive patients who underwent PD from 2012 to 2015 were evaluated. The patients’ perioperative data including the computed tomography (CT) parameters were collected. The minimum, maximum, and mean CT attenuation values (HUmin, HUmax, and HUmean, respectively) were extracted from the pancreatic parenchyma (≥ 100 pixels), and the standard deviation of these values (HUSD) was determined from the slice in which the superior mesenteric and splenic veins were merged. PF was defined as grade B or C according to the International Study Group for Pancreatic Fistula criteria.ResultsThe PF occurrence rate (grade B or C) was 25.3% in 75 patients. A multivariate analysis identified a larger HUSD (odds ratio 3.092; 95% CI 1.018–9.394) and higher amylase concentration in drainage fluid on postoperative day 1 (odds ratio 1.0001; 95% CI 1.00001–1.00022) as significant risk factors for PF.ConclusionsThe HUSD of preoperative CT attenuation values in the pancreatic parenchyma was found to be an independent predictor for PF after PD and it might therefore positively contribute to the perioperative management of PD.

Median arcuate ligament syndrome and aneurysm in the pancreaticoduodenal artery detected by retroperitoneal hemorrhage: A case report

Here, we report a case with successful treatment of inferior pancreaticoduodenal artery aneurysm rupture due to celiac artery trunk compression caused by the median arcuate ligament. When clinicians see visceral aneurysms, the possibility of arcuate midline ligament compression syndrome (MALS) and ligamentectomy for MALS should be considered.

α‐Tocopherol promotes HaCaT keratinocyte wound repair through the regulation of polarity proteins leading to the polarized cell migration

In many developed countries including Japan, how to care the bedridden elderly people with chronic wounds such as decubitus becomes one of the most concerned issues. Although antioxidant micronutrients including vitamin E, especially α-tocopherol (α-Toc), are reported to shorten a period of wound closure, the promoting effect of α-Toc on wound healing independent of its antioxidant activity remains to be fully elucidated. The aim of this study was to examine whether α-Toc affects wound-mediated HaCaT keratinocyte polarization process including the recruitment of polarity regulating proteins, leading to wound repair independently of its antioxidant activity. We investigated the effects of α-Toc and other antioxidants such as Trolox, a cell-permeable α-Toc analog on the migration, proliferation, and cell polarization of HaCaT keratinocytes after wounding. We analyzed the localization and complex formation of polarity proteins, partitioning defective 3 (Par3), and atypical protein kinase C (aPKC), and aPKC activity by immunohistochemistry, immunoprecipitation analyses, and in vitro kinase assays, respectively. α-Toc but not other antioxidants enhanced the wound closure and cell polarization in HaCaT keratinocytes after wounding. α-Toc regulated the localization and complex formation of Par3 and aPKC during wound healing. Knockdown of aPKC or Par3 abrogated α-Toc-mediated promotion of the wound closure and cell polarization in HaCaT keratinocytes. Furthermore, aPKC kinase activity was significantly increased in α-Toc-treated cells through activation of phosphatidylinositol 3-kinase/Akt signaling pathway. These results suggest that α-Toc promotes HaCaT keratinocyte wound repair by regulating the aPKC kinase activity and the formation of aPKC-Par3 complex.

C-Reactive Protein/Albumin Ratio and Prognostic Nutritional Index Are Strong Prognostic Indicators of Survival in Resected Pancreatic Ductal Adenocarcinoma

Abstract Purpose: We evaluated the clinical importance, such as the occurrence of postoperative pancreatic fistula (POPF) or prognosis, of preoperative serum markers of chronic inflammation, nutrition, and immunity, as well as that of serum tumor markers after curative resection of pancreatic ductal adenocarcinomas (PDACs). Methods: Between 2006 and 2015, 43 patients with PDACs underwent curative resection at Tottori Prefectural Central Hospital. We analyzed which preoperative indicators (i.e., C-reactive protein/albumin ratio [CAR], neutrophil/lymphocyte ratio [NLR], prognostic nutritional index [PNI], carcinoembryonic antigen [CEA], and carbohydrate antigen 19-9 [CA 19-9]) were the most relevant risk factors for occurrence of POPF and poor patient survival. Results: POPF was detected in 8/43 (18.6%) patients. One patient died of pancreatic fistula at 2 months postoperatively. Among nine candidate factors (operative procedure, operation time, tumor stage, preoperative serum amylase, preoperative CAR, NLR, PNI, CEA, and CA 19-9), we did not identify any significant risk factor for the occurrence of POPF. The 5-year overall survival (OS) rate of the 43 patients was 22.4%, and the overall median survival time was 21 months. The multivariate OS analysis demonstrated that high CAR and low PNI were strong preoperative markers of poor prognosis independently of tumor stage. Conclusions: Preoperative CAR and PNI are useful prognostic markers for patients with operable PDACs.

Biopsy findings on a stable recipient after secondary donor specific antibody (DSA) positive and ABO incompatible kidney transplantation

Using desensitization protocol, we performed a secondary donor specific antibody (DSA) positive and ABO incompatible kidney transplantation. One‐hour biopsy showed no C4d deposition. The protocol biopsy after 2 weeks showed diffuse C4d deposition with peritubulitis. After 12 weeks, however, the protocol biopsy showed disappearance of tubulitis in spite of remaining C4d deposition. The recipient was in stable condition with excellent graft function despite high titer of the DSA. Monitoring of protocol biopsy is critical while antibody titer and the interpretation of the histological findings correlating with clinical markers must be considered.