Portal circulation

  • 文章类型: Journal Article
    肝硬化门静脉血栓形成(PVT)的病理生理学仍未完全了解。门静脉循环中脂多糖(LPS)水平升高与高凝显著相关,增加血小板活化和内皮功能障碍。该研究的目的是调查LPS是否与门静脉血流减少有关。Virchow三合会的第三个组成部分,以及潜在的机制。血清亚硝酸盐/硝酸盐,作为一氧化氮(NO)生成的标志,在20例接受经颈静脉肝内门体分流术(TIPS)的肝硬化患者的门静脉和体循环中测量了LPS;在每位患者中还测量了门静脉血流速度(PVV),并与NO和LPS水平相关。与体循环相比,门静脉中的血清亚硝酸盐/硝酸盐和LPS显着升高;LPS与血清亚硝酸盐/硝酸盐之间存在显着相关性(R=0.421;p<0.01)。TIPS前后的PVV中位数为15cm/s(6-40)和31cm/s(14-79),分别。PVV与NO和LPS的相关性分析显示PVV与门静脉NO浓度呈显著负相关(R=-0.576;p=0.020),但不是LPS。内皮细胞的体外研究表明,LPS增强内皮NO的生物合成,被L-NAME抑制了,一氧化氮合酶的抑制剂,或TAK-242,TLR4,LPS受体的抑制剂;这种作用是通过上调eNOS和iNOS来实现的。研究表明,在肝硬化中,内毒素血症可能是通过NO和,因此,为PVT的发展做出贡献。
    Pathophysiology of portal vein thrombosis (PVT) in cirrhosis is still not entirely understood. Elevated levels of lipopolysaccharides (LPS) in portal circulation are significantly associated with hypercoagulation, increased platelet activation and endothelial dysfunction. The aim of the study was to investigate if LPS was associated with reduced portal venous flow, the third component of Virchow\'s triad, and the underlying mechanism. Serum nitrite/nitrate, as a marker of nitric oxide (NO) generation, and LPS were measured in the portal and systemic circulation of 20 patients with cirrhosis undergoing transjugular intrahepatic portosystemic shunt (TIPS) procedure; portal venous flow velocity (PVV) was also measured in each patient and correlated with NO and LPS levels. Serum nitrite/nitrate and LPS were significantly higher in the portal compared to systemic circulation; a significant correlation was found between LPS and serum nitrite/nitrate (R = 0.421; p < 0.01). Median PVV before and after TIPS was 15 cm/s (6-40) and 31 cm/s (14-79), respectively. Correlation analysis of PVV with NO and LPS showed a statistically significant negative correlation of PVV with portal venous NO concentration (R = - 0.576; p = 0.020), but not with LPS. In vitro study with endothelial cells showed that LPS enhanced endothelial NO biosynthesis, which was inhibited by L-NAME, an inhibitor of NO synthase, or TAK-242, an inhibitor of TLR4, the LPS receptor; this effect was accomplished by up-regulation of eNOS and iNOS. The study shows that in cirrhosis, endotoxemia may be responsible for reduced portal venous flow via overgeneration of NO and, therefore, contribute to the development of PVT.
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  • 文章类型: Journal Article
    在生理葡萄糖稳态中,肝脏在从门静脉循环中提取葡萄糖和作为糖原储存以在禁食时通过糖原分解释放中起着至关重要的作用。此外,胰腺分泌的胰岛素通过肝脏首过部分从体循环中消除。因此,患有先天性门体分流术的患者表现出独特的组合:(a)由于胰岛素消除减少而导致的吸收后高胰岛素血症性低血糖(HH)和(b)由于糖原分解减少而导致的空腹(酮症)低血糖.因此,患有门体分流的患者对门静脉循环和肝功能在葡萄糖稳态的不同阶段的作用提供了重要的见解。
    In physiological glucose homeostasis, the liver plays a crucial role in the extraction of glucose from the portal circulation and storage as glycogen to enable release through glycogenolysis upon fasting. In addition, insulin secreted by the pancreas is partly eliminated from the systemic circulation by hepatic first-pass. Therefore, patients with a congenital porto-systemic shunt present a unique combination of (a) postabsorptive hyperinsulinemic hypoglycaemia (HH) because of decreased insulin elimination and (b) fasting (ketotic) hypoglycaemia because of decreased glycogenolysis. Patients with porto-systemic shunts therefore provide important insight into the role of the portal circulation and hepatic function in different phases of glucose homeostasis.
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  • 文章类型: Journal Article
    Circulating tumor cells (CTC) enter the blood from many carcinomas and represent a likely source of metastatic dissemination. In contrast to the peripheral circulation, KRAS mutation- positive CTC thrive in the portal venous blood of patients with pancreatic ductal adenocarcinoma (PDAC). To analyze the essential interactions that contribute to carcinoma CTC growth and immune resistance, portal venous blood was collected during pancreatico-duodenectomy in 41 patients with peri-ampullary pathologies (PDAC = 11; ampullary adenocarcinoma (AA) = 15; distal cholangiocarcinoma (CC) = 6; IPMN = 7; non-malignant pancreatitis = 2). FACS-isolated cell populations from the portal circulation were reconstituted ex vivo using mixed cell reaction cultures (MCR). During the first 48hr, PDAC, AA, and CC patient CTC were all highly proliferative (mean 1.7 hr/cell cycle, 61.5% ± 20% growing cells) and resistant to apoptosis (mean 39% ±  25% apoptotic cells). PDAC CTC proliferation and resistance to T cell cytotoxicity were decreased among patients who received pre-operative chemotherapy (p = 0.0019, p = 0.0191, respectively). After 7 days in culture, CTC from PDAC, CC, and AA patients recruited multiple immune cell types, including CD105 + CD14 + myeloid fibroblasts, to organize into spheroid-like clusters. It was only in PDAC and CC-derived MCR that cluster formation promoted CTC survival, growth, and fibroblast differentiation. FACS depletion of CTC or myeloid fibroblast cells eliminated cluster network formation, and re-introduction of these cell populations reconstituted such ability. Our findings suggest that PDAC and CC CTC survival within the portal venous circulation is supported by their interactions with immune cells within multi-cell type clusters that could represent vectors of local recurrence and metastatic progression.
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  • 文章类型: Journal Article
    We performed brain magnetic resonance imaging in 40 patients after the Fontan procedure and 40 control subjects. Pituitary volumes in patients after Fontan were significantly larger than those in the control subjects (472 [425-527] vs 257 [182-311]; P < .0001), and were significantly related to central venous pressure.
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  • 文章类型: Journal Article
    The distinction between the medical and the surgical approach to disease has been a cornerstone of medical practice, and indeed with respect to the business and technology of medicine. It is common knowledge that diabetes is a medical disease-namely that drug therapy, whether it be via insulin or other medications, is the primary approach to therapy. This article argues that a reevaluation of the generalized (e.g., medication-based) approach to systemic blood sugar control may be in order. A consideration of the growing importance of interventional, device-based, or other surgical approaches to the primary management of diabetes has enormous implications for clinical practice as well as, of course, the business and technology of diabetes care.
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