264 research outputs found

    Hepatic FoxOs link insulin signaling with plasma lipoprotein metabolism through an apolipoprotein M/sphingosine-1-phosphate pathway

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    Multiple beneficial cardiovascular effects of HDL depend on sphingosine-1-phosphate (S1P). S1P associates with HDL by binding to apolipoprotein M (ApoM). Insulin resistance is a major driver of dyslipidemia and cardiovascular risk. However, the mechanisms linking alterations in insulin signaling with plasma lipoprotein metabolism are incompletely understood. The insulin-repressible FoxO transcription factors mediate key effects of hepatic insulin action on glucose and lipoprotein metabolism. This work tested whether hepatic insulin signaling regulates HDL-S1P and aimed to identify the underlying molecular mechanisms. We report that insulin-resistant, nondiabetic individuals had decreased HDL-S1P levels, but no change in total plasma S1P. This also occurred in insulin-resistant db/db mice, which had low ApoM and a specific reduction of S1P in the HDL fraction, with no change in total plasma S1P levels. Using mice lacking hepatic FoxOs (L-FoxO1,3,4), we found that hepatic FoxOs were required for ApoM expression. Total plasma S1P levels were similar to those in controls, but S1P was nearly absent from HDL and was instead increased in the lipoprotein-depleted plasma fraction. This phenotype was restored to normal by rescuing ApoM in L-FoxO1,3,4 mice. Our findings show that insulin resistance in humans and mice is associated with decreased HDL-associated S1P. Our study shows that hepatic FoxO transcription factors are regulators of the ApoM/S1P pathway

    Fish, Mercury, Selenium and Cardiovascular Risk: Current Evidence and Unanswered Questions

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    Controversy has arisen among the public and in the media regarding the health effects of fish intake in adults. Substantial evidence indicates that fish consumption reduces coronary heart disease mortality, the leading cause of death in developed and most developing nations. Conversely, concerns have grown regarding potential effects of exposure to mercury found in some fish. Seafood species are also rich in selenium, an essential trace element that may protect against both cardiovascular disease and toxic effects of mercury. Such protective effects would have direct implications for recommendations regarding optimal selenium intake and for assessing the potential impact of mercury exposure from fish intake in different populations. Because fish consumption appears to have important health benefits in adults, elucidating the relationships between fish intake, mercury and selenium exposure, and health risk is of considerable scientific and public health relevance. The evidence for health effects of fish consumption in adults is reviewed, focusing on the strength and consistency of evidence and relative magnitudes of effects of omega-3 fatty acids, mercury, and selenium. Given the preponderance of evidence, the focus is on cardiovascular effects, but other potential health effects, as well as potential effects of polychlorinated biphenyls and dioxins in fish, are also briefly reviewed. The relevant current unanswered questions and directions of further research are summarized

    Detection and quantification of new psychoactive substances (NPSs) within the evolved "legal high" product, NRG-2, using high performance liquid chromatography-amperometric detection (HPLC-AD)

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    The global increase in the production and abuse of cathinone-derived New Psychoactive Substances (NPSs) has developed the requirement for rapid, selective and sensitive protocols for their separation and detection. Electrochemical sensing of these compounds has been demonstrated to be an effective method for the in-field detection of these substances, either in their pure form or in the presence of common adulterants, however, the technique is limited in its ability to discriminate between structurally related cathinone-derivatives (for example: (±)-4′-methylmethcathinone (4-MMC, 2a) and (±)-4′-methyl-N-ethylmethcathinone (4-MEC, 2b) when they are both present in a mixture. In this paper we demonstrate, for the first time, the combination of HPLC-UV with amperometric detection (HPLC-AD) for the qualitative and quantitative analysis of 4-MMC and 4-MEC using either a commercially available impinging jet (LC-FC-A) or custom-made iCell channel (LC-FC-B) flow-cell system incorporating embedded graphite screen-printed macroelectrodes. The protocol offers a cost-effective, reproducible and reliable sensor platform for the simultaneous HPLC-UV and amperometric detection of the target analytes. The two systems have similar limits of detection, in terms of amperometric detection [LC-FC-A: 14.66 μg mL−1 (2a) and 9.35 μg mL−1 (2b); LC-FC-B: 57.92 μg mL−1 (2a) and 26.91 μg mL−1 (2b)], to the previously reported oxidative electrochemical protocol [39.8 μg mL−1 (2a) and 84.2 μg mL−1 (2b)], for two synthetic cathinones, prevalent on the recreational drugs market. Though not as sensitive as standard HPLC-UV detection, both flow cells show a good agreement, between the quantitative electroanalytical data, thereby making them suitable for the detection and quantification of 4-MMC and 4-MEC, either in their pure form or within complex mixtures. Additionally, the simultaneous HPLC-UV and amperometric detection protocol detailed herein shows a marked improvement and advantage over previously reported electroanalytical methods, which were either unable to selectively discriminate between structurally related synthetic cathinones (e.g. 4-MMC and 4-MEC) or utilised harmful and restrictive materials in their design

    Site-specific anti-tumor immunity: differences in DC function, TGF-beta production and numbers of intratumoral Foxp3+ Treg

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    Gliomas localized within the CNS are generally not rejected by the immune system despite being immunogenic. This failure of the immune system has been associated both with glioma-derived immunosuppressive molecules and the immune-privileged state of the CNS. However, the relative contribution of tumor location to the glioma-mediated immunosuppression, as well as the immune mechanisms involved in the failure of glioma rejection are not fully defined. We report here that syngeneic GL261 gliomas growing either intracranially or subcutaneously in mice are infiltrated by DC and T cells. However, only subcutaneous gliomas elicit an effective anti-tumor immune response. In contrast to DC infiltrating subcutaneously grown GL261 gliomas, tumor-infiltrating DC from intracranial gliomas do not activate antigen-dependent T-cell proliferation in vitro. In addition, brain-localized GL261 gliomas are characterized by significantly higher numbers of Foxp3(+) Treg and higher levels of TGF-beta1 mRNA and protein expression when compared with GL261 gliomas in the skin. Our data show that gliomas in the CNS, but not in the skin, give rise to TGF-beta production and accumulation of both Treg and functionally impaired DC. Thus, not the tumor itself, but its location dictates the efficiency of the anti-tumor immune response

    The Structural System of Vikalpayogaparivarto nāma ṣaṣṭamah in Saṃdhinirmocana Sūtra: Focusing on 'phags pa dgong pa nges par 'grel pa'i mod'i rnam par bshad pa

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    This writing considers the structural system of Vikalpayogaparivarto nāma ṣaṣṭamah (Hence, VYNṢ) in Saṃdhinirmocana Sūtra (Hence, SNS) focusing on 'phags pa dgong pa nges par 'grel pa'i mod'i rnam par bshad pa (Hence, rnam bshad) by Cog ro Klu'i rgyal-mtshan, one of the great translators of Tibetan Buddhism in the mid 8th to 9th. Rnam bshad is very long and contains extensive and detail explanation of SNS, which has rarely been studied in academia in spite of having different and new interpretation from the commentary of Woncheuk. He states VYNṢ is organized into eighteen stages of śamatha and vipaśyanā while according to Klu'i rgyal-mtshan, it is organized into six aspects of the way of śamatha and vipaśyanā and fourteen stages. His explination of its structure shows dimensionalized system while that of Woncheuk is simple.</jats:p
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