Energy and glucose homeostasis are regulated by food intake and liver glucose production, respectively. The upper intestine has a critical role in nutrient digestion and absorption. However, studies indicate that upper intestinal lipids inhibit food intake as well in rodents and humans by the activation of an intestine-brain axis. In parallel, a brain-liver axis has recently been proposed to detect blood lipids to inhibit glucose production in rodents. Thus, we tested the hypothesis that upper intestinal lipids activate an intestine-brain-liver neural axis to regulate glucose homeostasis. Here we demonstrate that direct administration of lipids into the upper intestine increased upper intestinal long-chain fatty acyl-coenzyme A (LCFA-CoA) levels and suppressed glucose production. Co-infusion of the acyl-CoA synthase inhibitor triacsin C or the anaesthetic tetracaine with duodenal lipids abolished the inhibition of glucose production, indicating that upper intestinal LCFA-CoAs regulate glucose production in the preabsorptive state. Subdiaphragmatic vagotomy or gut vagal deafferentation interrupts the neural connection between the gut and the brain, and blocks the ability of upper intestinal lipids to inhibit glucose production. Direct administration of the N-methyl-d-aspartate ion channel blocker MK-801 into the fourth ventricle or the nucleus of the solitary tract where gut sensory fibres terminate abolished the upper-intestinal-lipid-induced inhibition of glucose production. Finally, hepatic vagotomy negated the inhibitory effects of upper intestinal lipids on glucose production. These findings indicate that upper intestinal lipids activate an intestine-brain-liver neural axis to inhibit glucose production, and thereby reveal a previously unappreciated pathway that regulates glucose homeostasis.
Oral sensory signals drive dietary fat intake, but the neural mechanisms underlying this process are largely unknown. The endocannabinoid system has gained recent attention for its central and peripheral roles in regulating food intake, energy balance, and reward. Here, we used a sham-feeding paradigm, which isolates orosensory from postingestive influences of foods, to examine whether endocannabinoid signaling participates in the positive feedback control of fat intake. Sham feeding a lipid-based meal stimulated endocannabinoid mobilization in the rat proximal small intestine by altering enzymatic activities that control endocannabinoid metabolism. This effect was abolished by surgical transection of the vagus nerve and was not observed in other peripheral organs or in brain regions that control feeding. Sham feeding of a nutritionally complete liquid meal produced a similar response to that of fat, whereas protein or carbohydrate alone had no such effect. Local infusion of the CB 1 -cannabinoid receptor antagonist, rimonabant, into the duodenum markedly reduced fat sham feeding. Similarly to rimonabant, systemic administration of the peripherally restricted CB 1 -receptor antagonist, URB 447, attenuated sham feeding of lipid. Collectively, the results suggest that the endocannabinoid system in the gut exerts a powerful regulatory control over fat intake and might be a target for antiobesity drugs.
Malignant pleural effusion (MPE) is a common complication of advanced non-small cell lung cancer (NSCLC). Bevacizumab, a humanized monoclonal antibody against vascular endothelial growth factor (VEGF), has been shown to be efficient in suppressing the accumulation of pleural fluid. However, whether intrapleural delivery of bevacizumab can be used to treat MPE remains unknown. The aim of the present study was to evaluate the efficacy and safety of combined intrapleural therapy with bevacizumab and cisplatin, an antineoplastic agent, in controlling MPE. A total of 72 NSCLC study subjects with MPE were randomly assigned to one of two groups. The first group received intrapleural bevacizumab (300 mg) with cisplatin (30 mg) therapy and the second group received intrapleural cisplatin (30 mg) therapy alone. Pleural fluid was collected from both groups prior to and following treatment. The levels of VEGF and carcinoembryonic antigen (CEA) in the pleural fluid were determined by ELISA. In 70 evaluable study subjects, the curative efficacy in the bevacizumab group was significantly higher than that found in the cisplatin group (83.33 vs. 50.00%, respectively; p<0.05). Therapy with combined bevacizumab plus cisplatin significantly reduced VEGF levels in the pleural fluid (p<0.01). In the bevacizumab group, the levels of VEGF in the pleural fluid were significantly lower compared to those of the cisplatin group after treatment, which showed greater efficacy (p<0.01). In addition, combination therapy showed greater efficacy in the patients with high levels of VEGF expression (p<0.01). There was no significant difference in grade III/IV adverse events between the two groups. All procedures were well tolerated by the patients. Combined intrapleural therapy with bevacizumab and cisplatin was effective and safe in managing NSCLC-mediated MPE. We propose that VEGF expression levels in MPE could serve as a prognostic marker for bevacizumab therapy.
Glucocorticoids are known to promote the development of metabolic syndrome through the modulation of both feeding pathways and metabolic processes; however, the precise mechanisms of these effects are not well-understood. Recent evidence shows that glucocorticoids possess the ability to increase endocannabinoid signaling, which is known to regulate appetite, energy balance, and metabolic processes through both central and peripheral pathways. The aim of this study was to determine the role of endocannabinoid signaling in glucocorticoid-mediated obesity and metabolic syndrome. Using a mouse model of excess corticosterone exposure, we found that the ability of glucocorticoids to increase adiposity, weight gain, hormonal dysregulation, hepatic steatosis, and dyslipidemia was reduced or reversed in mice lacking the cannabinoid CB 1 receptor as well as mice treated with the global CB 1 receptor antagonist AM251. Similarly, a neutral, peripherally restricted CB 1 receptor antagonist (AM6545) was able to attenuate the metabolic phenotype caused by chronic corticosterone, suggesting a peripheral mechanism for these effects. Biochemical analyses showed that chronic excess glucocorticoid exposure produced a significant increase in hepatic and circulating levels of the endocannabinoid anandamide, whereas no effect was observed in the hypothalamus. To test the role of the liver, specific and exclusive deletion of hepatic CB 1 receptor resulted in a rescue of the dyslipidemic effects of glucocorticoid exposure, while not affecting the obesity phenotype or the elevations in insulin and leptin. Together, these data indicate that glucocorticoids recruit peripheral endocannabinoid signaling to promote metabolic dysregulation, with hepatic endocannabinoid signaling being especially important for changes in lipid metabolism.corticosterone | 2-AG | anandamide | obesity | liver O besity and associated cardiometabolic diseases, such as type 2 diabetes, represent major contributors to morbidity and mortality (1, 2). Persistent exposure to environmental and psychological stress and the concomitant increase in circulating glucocorticoids (GCs; the primary stress hormones) are believed to be contributing factors to the epidemic of obesity and metabolic syndrome (3-6). Furthermore, patients receiving exogenous GCs subsequent to an organ transplant or for the treatment of inflammatory-related illnesses show several symptoms of the metabolic syndrome (7). Despite this relationship, the mechanisms by which GCs produce these changes in weight regulation and metabolism remain unclear.It has been clearly shown that GCs can mobilize the endocannabinoid (eCB) system, which is essential for many of the effects of GCs, including negative feedback regulation of the hypothalamic-pituitary-adrenal axis, suppression of sexual behavior, and alterations in memory consolidation (8-11). eCBs are also potent regulators of feeding and metabolism, with effects that parallel those of GCs, such as increased feeding, reduced energy expenditure, fat accumulation ...
Ingestion of dietary fat stimulates production of the small-intestinal satiety factors oleoylethanolamide (OEA) and N-palmitoyl-phosphatidylethanolamine (NPPE), which reduce food intake through a combination of local (OEA) and systemic (NPPE) actions. Previous studies have shown that sympathetic innervation of the gut is necessary for duodenal infusions of fat to induce satiety, suggesting that sympathetic activity may engage small-intestinal satiety signals such as OEA and NPPE. In the present study, we show that surgical resection of the sympathetic celiac superior mesenteric ganglion, which sends projections to the upper gut, abolishes feeding-induced OEA production in rat small-intestinal cells. These effects are accounted for by suppression of OEA biosynthesis, and are mimicked by administration of the selective β2-adrenergic receptor antagonist, ICI-118,551. We further show that sympathetic ganglionectomy or pharmacological blockade of β2-adrenergic receptors prevents NPPE release into the circulation. In addition, sympathetic ganglionectomy increases meal frequency and lowers satiety ratio, and these effects are corrected by pharmacological administration of OEA. The results suggest that sympathetic activity controls fat-induced satiety by enabling the coordinated production of local (OEA) and systemic (NPPE) satiety signals in the small intestine.
The prognostic role of programmed death ligand-1 (PD-L1) expression in hepatocellular carcinoma (HCC) has been widely studied but the results are controversial. In this comprehensive meta-analysis, we elucidated the clinical value of PD-L1 in HCC. Relevant studies were systematically searched in the Cochrane Library, EMBASE, and PubMed until June 27, 2019. Eligible studies were validated for the prognostic effect of PD-L1 on the overall survival (OS), disease-free survival (DFS), and relapse-free survival (RFS) in HCC using a hazard ratio (HR) and its 95% confidence interval (95% CI). Twenty-three studies with 3529 patients were involved in this meta-analysis. The pooled results revealed that high membrane-bound PD-L1 (mPD-L1) expression was associated with poor OS (HR: 1.42; 95% CI: 1.12–1.80; P = 0.004) and had no significant correlation with RFS (HR: 1.14; 95% CI: 0.85–1.54; P = 0.39), and DFS (HR: 1.36; 95% CI: 0.81–2.28; P = 0.25). The results also indicated that high soluble PD-L1 (sPD-L1) levels were associated with worse OS (HR: 2.93; 95% CI: 2.20–3.91; P < 0.00001). In addition, high mPD-L1 expression was associated with high alpha-fetoprotein levels (AFP; OR = 1.46; 95% CI: 1.16–1.84; P = 0.001), hepatitis (OR = 0.72; 95% CI: 0.54–0.98; P = 0.03), poor tumor differentiation (OR = 0.68; 95% CI: 0.55–0.84; P = 0.03), and tumor-infiltrating lymphocytes (OR = 3.39; 95% CI: 1.06–10.91; P = 0.04). The mPD-L1 expression had no significant correlation with age, number of tumors, gender, tumor size, liver cirrhosis, vascular invasion, tumor encapsulation, or TNM stage. The study revealed that high mPD-L1 expression in the tumor tissue and high sPD-L1 levels were associated with shorter OS in HCC. Moreover, overexpression of mPD-L1 was significantly associated with poor tumor differentiation, hepatitis, AFP elevation, and tumor-infiltrating lymphocytes.
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