A 2,3-diphenylpyrido[1,2-a] pyrimidin-4-one derivative inhibits specific angiogenic factors induced by TNF-\u3b1

Low-grade chronic inflammation is a key process of angiogenesis in tumour progression. We investigated whether a synthetic analogue of apigenin, the 2-(3,4-dimethoxyphenyl)-3-phenyl-4H-pyrido[1,2-a] pyrimidin-4-one (called DB103), interfered with the mechanisms involved in the angiogenic process induced by the inflammatory cytokine tumour necrosis factor (TNF\u3b1). In endothelial cells, DB103 but not apigenin reduced the TNF\u3b1-induced oxidative stress. DB103 inhibited the activation of ERK1/2 but not JNK, p38 and Akt kinases, while apigenin was not so selective because it inhibited essentially all examined kinases. Similarly, apigenin inhibited the TNF\u3b1-induced transcription factors CREB, STAT3, STAT5 and NF-kB, while DB103 acted only on NFinhibited the induced-release of angiogenic factors such as monocyte chemotactic protein-1, interleukin-6 (IL-6) and angiopoietin-2 but not IL-8, while apigenin reduced the IL-6 and IL-8 release. DB103 revealed a better ability than apigenin to modulate proangiogenic responses induced by an inflammatory microenvironment

Distinct contributions of metabolic dysfunction and genetic risk factors in the pathogenesis of non-alcoholic fatty liver disease

Background & Aims: There is substantial inter-individual variability in the risk of non-alcoholic fatty liver disease (NAFLD). Part of which is explained by insulin resistance (IR) ('MetComp') and part by common modifiers of genetic risk ('GenComp'). We examined how IR on the one hand and genetic risk on the other contribute to the pathogenesis of NAFLD. Methods: We studied 846 individuals: 492 were obese patients with liver histology and 354 were individuals who underwent intrahepatic triglyceride measurement by proton magnetic resonance spectroscopy. A genetic risk score was calculated using the number of risk alleles in PNPLA3, TM6SF2, MBOAT7, HSD17B13 and MARC1. Substrate concentrations were assessed by serum NMR metabolomics. In subsets of participants, non-esterified fatty acids (NEFAs) and their flux were assessed by D-5-glycerol and hyperinsulinemic-euglycemic clamp (n = 41), and hepatic de novo lipogenesis (DNL) was measured by D2O (n = 61). Results: We found that substrate surplus (increased concentrations of 28 serum metabolites including glucose, glycolytic intermediates, and amino acids; increased NEFAs and their flux; increased DNL) characterized the 'MetComp'. In contrast, the 'GenComp' was not accompanied by any substrate excess but was characterized by an increased hepaticmitochondrial redox state, as determined by serum beta-hydroxybutyrate/acetoacetate ratio, and inhibition of hepatic pathways dependent on tricarboxylic acid cycle activity, such as DNL. Serum beta-hydroxybutyrate/acetoacetate ratio correlated strongly with all histological features of NAFLD. IR and hepatic mitochondrial redox state conferred additive increases in histological features of NAFLD. Conclusions: These data show that the mechanisms underlying 'Metabolic' and 'Genetic' components of NAFLD are fundamentally different. These findings may have implications with respect to the diagnosis and treatment of NAFLD. Lay summary: The pathogenesis of non-alcoholic fatty liver disease can be explained in part by a metabolic component, including obesity, and in part by a genetic component. Herein, we demonstrate that the mechanisms underlying these components are fundamentally different: the metabolic component is characterized by hepatic oversupply of substrates, such as sugars, lipids and amino acids. In contrast, the genetic component is characterized by impaired hepatic mitochondrial function, making the liver less able to metabolize these substrates. (C) 2021 The Author(s). Published by Elsevier B.V. on behalf of European Association for the Study of the Liver.Peer reviewe

Saturated fat is more metabolically harmful for the human liver than unsaturated fat or simple sugars

OBJECTIVE Nonalcoholic fatty liver disease (i.e., increased intrahepatic triglyceride [IHTG] content), predisposes to type 2 diabetes and cardiovascular disease. Adipose tissue lipolysis and hepatic de novo lipogenesis (DNL) are the main pathways contributing to IHTG. We hypothesized that dietary macronutrient composition influences the pathways, mediators, and magnitude of weight gain-induced changes in IHTG. RESEARCH DESIGN AND METHODS We overfed 38 overweight subjects (age 48 ± 2, BMI 31 ± 1 kg/m2, liver fat 4.7 ± 0.9%) 1,000 extra kcal/day of saturated (SAT) or unsaturated (UNSAT) fat or simple sugars (CARB) for 3 weeks. We measured IHTG (1H-MRS), pathways contributing to IHTG (lipolysis ([2H5]glycerol) and DNL (2H2O) basally and during euglycemic hyperinsulinemia, insulin resistance, endotoxemia, plasma ceramides, and adipose tissue gene expression at 0 and 3 weeks. RESULTS Overfeeding SAT increased IHTG more (+55%) than UNSAT (+15%, P < 0.05). CARB increased IHTG (+33%) by stimulating DNL (+98%). SAT significantly increased while UNSAT decreased lipolysis. SAT induced insulin resistance and endotoxemia and significantly increased multiple plasma ceramides. The diets had distinct effects on adipose tissue gene expression. CONCLUSIONS Macronutrient composition of excess energy influences pathways of IHTG: CARB increases DNL, while SAT increases and UNSAT decreases lipolysis. SAT induced greatest increase in IHTG, insulin resistance, and harmful ceramides. Decreased intakes of SAT could be beneficial in reducing IHTG and the associated risk of diabetes

Metabolomic markers of liver damage and their changes during the advancement of hepatic disease

The liver is a key organ in whole body metabolism and waste handling and small-molecule metabolites have been proven to be excellent markers of liver function. Hepatic lipotoxicity due to elevated free fatty acid (FFA), inflammatory adipokines, impaired β-oxidation, together with insulin resistance (IR), lead to metabolic dysregulation, mitochondrial impairment and oxidative stress. These events have a significant role also in determining hepatocyte damage and result in profound changes in hepatic inflammation and gene expression, leading not only to fatty liver disease (FLD), but also to fibrosis, apoptosis and ultimately to hepatocellular carcinoma (HCC). The aims of this thesis were to identify, by “omics” Mass Spectrometry (MS) techniques, non-invasive biomarkers of hepatic dysfunction and tissue damage in subjects with different degree of liver disease from fatty liver, to fibrosis to HCC and to analyze if these biomarkers could change after liver transplantation. The thesis was developed in three work packages (WPs). In WP1 I have analyzed if metabolomics indexes could be used as markers of the severity of non alcoholic fatty liver disease (NAFLD). By analyzing plasma samples of 45 subjects with biopsy proven NAFLD, I have identified indexes of de novo lipogenesis and amino acid metabolism associated with the severity of liver disease. I have also demonstrated that adipose tissue (Adipo-IR), hepatic (Hep-IR) and peripheral (HOMA-IR) insulin resistance indexes were increased in those with higher degree of steatosis and/or fibrosis. In the same WP I have developed a new metabolic index (GSG_index = glutamate/(serine+glycine)) that was associated with worsening of liver fibrosis. This metabolic index is the expression of increased oxidative stress/glutathione and TCA cycle activities and is increased proportionally to fibrosis. In WP2, I evaluated if the indexes discovered in WP1, and associated with liver fibrosis in NAFLD, were also altered in subjects with HCC. Adipo-IR and HOMA-IR were increased proportionally to the severity of liver disease. Also the DNL and the new GSG index were increased in patients with HCC compared to those with NAFLD. In WP3 I have analyzed if and how metabolomic markers of chronic liver disease change after liver transplantation (LT). I have analyzed the plasma metabolites of 22 subjects before LT and during follow up at 3, 6, and 12 months after surgery. I have found that after LT there was an improvement in Adipo-IR and HOMA-IR already 3 months after surgery and this improvement was maintained at 6 and 12 months. In addition, I have observed an improvement in fatty acid composition and aromatic amino acid concentrations but no changes in DNL and GSG indexes. In conclusion, severity of liver disease is strongly associated with several biomarkers discovered through metabolomics analysis and with the degree of insulin resistance, not only at the level of the liver but also of muscle and adipose tissue. In addition, I identified a set of metabolomic indexes able to mark differences in degree of liver fibrosis and presence of HCC, indicating metabolic dysfunction as one of the major risk factor for liver disease