Prostaglandin E(2)(PGE(2)) and prostaglandin E (EP) receptor signaling pathways have been implicated in the promotion of tumor growth and angiogenesis. However, little is known about their roles in lymphangiogenesis during tumor development. The present study evaluates whether endogenous PGE(2) exhibits a critical role in tumor-associated lymphangiogenesis. Treatment of male C57BL/6 mice with a cyclooxygenase-2 inhibitor, celecoxib, for seven days resulted in a 52.4% reduction in tumor size induced by subcutaneous injection of murine Lewis lung cells. Celecoxib treatment down-regulated the expression of vascular endothelial growth factor receptor (VEGFR)-3 in stromal tissues by 73.9%, and attenuated expression of podoplanin, a marker for lymphatic endothelial cells. To examine the role of host PGE receptor signaling, we tested four kinds of EP receptor knockout mice. At Day 7 after tumor cell implantation, EP3 receptor knockout mice, but not EP receptor knockout mice lacking EP1, EP2, or EP4, exhibited a 53.3% reduction in tumor weight, which was associated with a 74.5% reduction in VEGFR-3 mRNA expression in tumor stromal tissues. At Day 14, VEGFR-3 expression in EP3-/- mice remained significantly lower than that of their wild-type (WT) counterparts. The expression of VEGF-C in the tumor stromal tissues in EP3-/- mice were also reduced by 22.1%(Day 7) and 44.1%(Day 14), respectively. In addition, the level of immunoreactive podoplanin in the tumor tissues from EP3-/- mice was less than that of WT. These results suggest that host EP3 receptor signaling regulates tumor-associated lymphangiogenesis by up-regulating expression of VEGF-C and its receptor, VEGFR-3, in tumor stromal tissues. Host EP3 blockade together with COX-2 inhibition may be a novel therapeutic strategy to suppress tumor-associated lymphangiogenesis.

Chronic inflammation, which is characterized by the proliferation of granulation tissues, is known to be regulated by angiogenesis. Recent results suggest that bone marrow-derived (BM-derived) hematopoietic cells regulate angiogenesis in vivo. We previously reported that the angiogenesis occurring during chronic inflammation is enhanced in response to the endogenous prostaglandins (PGs) derived from an inducible cyclooxygenase-2 (COX-2). In the present study, we examined the role of BM-derived cells expressing an E-type PG receptor subtype, EP3, in sponge-induced angiogenesis. The replacement of wild-type (WT) BM with BM cells (BMCs) from green fluorescent protein (GFP) transgenic mice revealed that the formation of granulation tissue around the sponge implants developed via the recruitment of BMCs. This recruitment was enhanced by topical injections of vascular endothelial growth factor (VEGF)-A, and a VEGF-dependent increase in the recruitment of BMCs was inhibited by a COX-2 inhibitor, celecoxib. FACS analysis of the granulation tissues after treatment with collagenase revealed that the Mac-1-positive macrophage fraction was enhanced by topical injections of VEGF-A, and that this increased recruitment of Mac-1-positive BMCs was inhibited by celecoxib. Selective knockdown of EP3 performed by BM transplantation with BMCs isolated from EP3 knockout (EP3) mice reduced sponge-induced angiogenesis, as estimated by mean vascular number and CD31 expression in the granulation tissues. This reduction in angiogenesis in EP3(-/-) BM chimeric mice was accompanied by reductions in the recruitment of BMCs, especially of Mac-1-positive cells and Gr-1-positive cells. These results indicate that the recruited bone marrow cells that express the EP3 receptor have a significant role in enhancing angiogenesis during chronic proliferative inflammation.

Cyclooxygenase (COX)-2 is known to correlate with poor cancer prognosis and to contribute to tumor metastasis. However, the precise mechanism of this phenomenon remains unknown. We have previously reported that host stromal prostaglandin E(2)(PGE(2))-prostaglandin E2 receptor (EP)3 signaling appears critical for tumor-associated angiogenesis and tumor growth. Here we tested whether the EP3 receptor has a critical role in tumor metastasis. Lewis lung carcinoma (LLC) cells were intravenously injected into WT mice and mice treated with the COX-2 inhibitor NS-398. The nonselective COX inhibitor aspirin reduced lung metastasis, but the COX-1 inhibitor SC560 did not. The expression of matrix metalloproteinases (MMP)-9 and vascular endothelial growth factor (VEGF)-A was suppressed in NS-398-treated mice compared with PBS-treated mice. Lungs containing LLC colonies were markedly reduced in EP3 receptor knockout (EP3(-/-)) mice compared with WT mice. The expression of MMP-9 and VEGF-A was downregulated in metastatic lungs of EP3(-/-) mice. An immunohistochemical study revealed that MMP-9-expressing endothelial cells were markedly reduced in EP3(-/-) mice compared with WT mice. When HUVEC were treated with agonists for EP1, EP2, EP3, or EP4, only the EP3 agonist enhanced MMP-9 expression. These results suggested that EP3 receptor signaling on endothelial cells is essential for the MMP-9 upregulation that enhances tumor metastasis and angiogenesis. An EP3 receptor antagonist may be useful to protect against tumor metastasis.(Cancer Sci 2009).

The purpose of this study was to assess the feasibility and effectiveness of graft fixation with a novel side graft holder for sequential or composite graft anastomosis in coronary artery bypass grafting (CABG). Records of 34 patients who underwent CABG using sequential or composite graft anastomosis technique were reviewed. The device was used on 47 anastomoses (sequential=43; composite graft=4). Excellent fixation and visualization of the graft was obtained in all patients without graft injury. Postoperative angiographic patency rate of distal anastomoses was 95.2%(arterial, 91.2%; venous, 96.7%). All sequential and composite graft anastomoses were patent and without stenosis. One operative death occurred due to low cardiac output after emergent CABG for acute myocardial infarction. No elective patient died during hospitalization. Postoperative complications occurred in 2 patients (ventricular fibrillation, 1; postoperative catheter intervention, 1). No perioperative myocardial infarctions or re-operations occurred. Our clinical experience shows that graft fixation with the device is safe, reliable, and effective for sequential and composite graft anastomosis during CABG. Keywords: Coronary artery bypass grafting; Anastomosis; Surgical instruments.

gamma-Secretase is a membrane protein complex that catalyzes intramembrane proteolysis of a variety of substrates including the amyloid beta precursor protein of Alzheimer's disease. Nicastrin (NCT), a single-pass membrane glycoprotein that harbors a large extracellular domain, is an essential component of the gamma-secretase complex. Here we report that overexpression of a single chain variable fragment (scFv) against NCT as an intrabody suppressed the gamma-secretase activity. Biochemical analyses revealed that the scFv disrupted the proper folding and the appropriate glycosyl maturation of the endogenous NCT, which are required for the stability of the gamma-secretase complex and the intrinsic proteolytic activity, respectively, implicating the dual role of NCT in the gamma-secretase complex. Our results also highlight the importance of the calnexin cycle in the functional maturation of the gamma-secretase complex. The engineered intrabodies may serve as rationally designed, molecular targeting tools for the discovery of novel actions of the membrane proteins.

To identify the location of pancreatic endocrine tumors, arterial stimulation and venous sampling (ASVS) is known to be useful for insulinoma and gastrinoma, but its usefulness for glucagonoma has not been verified to date. Here we report a case of glucagonoma that was diagnosed by ASVS with calcium loading, in which an approximately 6-fold increase of glucagon was observed in the splenic artery territory. MEN1 gene analysis verified the presence of a mutation and the glucagonoma was confirmed after operation. In conclusion, ASVS could be useful for the diagnosis of glucagonoma.

We describe a simple and safe technique to position a bipolar radio-frequency ablation device around the pulmonary veins when performing pulmonary vein isolation. The technique consists of insertion of a rubber catheter with stylet, originally an introducer from a left vent catheter, behind the pulmonary veins, and subsequent placement of the lower jaw of the ablation clamp using a rubber catheter to guide the device into position. This novel method avoids excessive compression or displacement of the heart and enables easy and safe positioning of the ablation device around the pulmonary veins.

We describe the construction and use of a novel side graft holder for coronary artery bypass grafting. The device is a hammer head-shaped clip used to hold the graft side securely but atraumatically during sequential or composite graft anastomosis. The side graft holder provides gentle stabilization and excellent visualization of the side of the graft without causing graft injury.

Recent results suggest that bone marrow (BM) derived hematopoietic cells are major components of tumor stroma and play crucial roles in tumor growth and angiogenesis. An E-type prostaglandin is known to regulate angiogenesis. We examined the role of BM-derivedcells expressing an E-type prostaglandin receptor subtype (EP3) in tumor-induced angiogenesis and tumor growth. The replacement of wild-type (WT) BM with BM cells (BMCs) from green fluorescent protein (GFP) transgenic mice revealed that the stroma developed via the recruitment of BMCs. Selective knockdown of EP3 by recruitment of genetically modified BMCs lacking EP3 receptors was performed by transplantation of BMCs from EP3 knockout (EP3(-/-))mice. Tumor growth and tumor-associated angiogenesis were suppressed in WT mice transplanted with BMCs from EP3(-/-) mice, but not in mice transplanted with BMCs from either EP1(-/-), EP2(-/-), or EP4(-/-) mice. Immunohistochemical analysis revealed that vascular endothelial growth factor (VEGF) expression was suppressed in the stroma of mice transplanted with BMCs from EP3(-/-) mice. EP3 signaling played a significant role in the recruitment of VEGFR-1- and VEGFR-2-positive cells from the BM to the stroma. These results indicate that the EP3 signaling expressed in bone marrow derived cells has a crucial role in tumor-associated angiogenesis and tumor growth with upregulation of the expression of the host stromal VEGF together with the recruitment of VEGFR-1/VEGFR-2 positive. The present study suggests that the blockade of EP3 signaling and the recruitment of EP3-expressing stromal cells may become a novel strategy to treat solid tumors.

It is suggested that an ATP-sensitive potassium channel blocker suppresses sodium-induced hypertension through increased secretion of urinary kallikrein. We reported that glibenclamide, an ATP-sensitive potassium channel blocker, accelerated dose-dependent secretion of renal kallikrein in sliced kidney cortex and in vivo in rats. In vehicle-treated normal Brown- Norway-Kitasato (nBN-Ki) rats, the administration of glibenclamide increased urinary kallikrein secretion, but changed neither the systolic blood pressure nor the urinary sodium on low (0.3%) NaCl diets. Although on high (8%) NaCl diets, the systolic blood pressure of the nBN-Ki rats administrated glibenclamide was significantly lower (P<0.05). The urinary levels of kallikrein and sodium of the nBN-Ki rats administrated glibenclamide were significantly increased (P<0.05, glibenclamide vs. vehicle). A similar result was obtained with a kidney-selective ATP-sensitive potassium blocker, N,N'-dicyclohexyl-4-morpholinecarboxamidine (U18177), in SD rats. Mutant kininogen-deficient Brown-Norway Katholiek (muBN-Ka) rats fed high (8%) NaCl diets showed an increase in urinary kallikrein levels, but showed neither hypotensive nor natriuretic actions by glibenclamide. A bradykinin B(2) receptor antagonist, 8-[3-[N-(E)-3-(6-acetamidopyridin-3-yl) acryloylglyycyl]-N-methylamino]-2,6-dichlorobenzyloxy]-2-methylquinoline (FR173657), which was administrated to SD rats, together with glibenclamide, abolished the hypotensive and natriuretic effects of glibenclamide in high-sodium (8%NaCl) hypertension, despite an accelerated secretion of urinary kallikrein. Therefore, these results indicate that glibenclamide, an ATP-sensitive potassium channel blocker suppressed sodium-induced hypertension through sodium excretion from the kidney resulting from accelerated secretion of urinary kallikrein.Hypertension Research (2009) 32, 220-226; doi:10.1038/hr.2008.33.