Relationship of Serum Inflammatory Biomarkers With Plaque Inflammation Assessed by FDG PET/CT The dal-PLAQUE Study

ObjectivesThis study sought to longitudinally investigate the relationship between a broad spectrum of serum inflammatory biomarkers and plaque inflammation assessed by 18F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT).BackgroundBoth plaque inflammation and serum biomarkers of inflammation are associated with atherothrombotic events; however, the relationship between them is unclear.MethodsWe conducted a post hoc analysis of the dal-PLAQUE (A Randomized Placebo-Controlled Study of the Effect of RO4607381 on Progression or Regression of Atherosclerotic Plaque in Patients With Coronary Heart Disease [CHD] Including Patients With Other CHD Risk Factors), a randomized, placebo-controlled study of dalcetrapib, a cholesteryl ester transfer protein inhibitor, in 130 patients with coronary heart disease, or coronary heart disease risk equivalents on stable lipid-lowering therapy. Baseline and change after 3-month follow-up in inflammatory biomarker levels and baseline and change after 3-month follow-up in aorta and carotid 18F-FDG PET/CT (mean maximum target-to-background ratio of the most diseased segment [TBRmds]) were analyzed.ResultsBaseline myeloperoxidase positively correlated with baseline carotid TBRmds (rho = 0.25, p = 0.02). This correlation remained at the 3-month follow-up and was independent of traditional cardiovascular disease risk factors. Baseline lipoprotein-associated phospholipase A2 mass correlated with aorta TBRmds (rho = 0.21, p = 0.03). However, this correlation disappeared at the 3-month follow-up and was not independent of cardiovascular disease risk factors. There was no association between change from baseline in myeloperoxidase or lipoprotein-associated phospholipase A2 mass and change from baseline in aorta and carotid TBRmds. Baseline and change from baseline in high sensitivity C-reactive protein, interleukin 6, soluble P-selectin, soluble E-selectin, soluble intracellular adhesion molecule 1, soluble vascular cell adhesion molecule 1, and matrix-metalloproteinase 3 and 9 did not correlate with baseline or change from baseline in carotid or aorta TBRmds.ConclusionsOur data show that, in patients with coronary heart disease or at high risk of coronary heart disease on stable lipid-lowering therapy, circulating myeloperoxidase levels are associated with carotid plaque inflammation. (A Randomized, Placebo-controlled Study of the Effect of RO4607381 on Progression or Regression of Atherosclerotic Plaque in Patients With Coronary Heart Disease [CHD] Including Patients With Other CHD Risk Factors [dal-PLAQUE]; NCT00655473

Hepatocyte nuclear factor-4α contributes to carbohydrate-induced transcriptional activation of hepatic fatty acid synthase

Refeeding a carbohydrate-rich meal after a fast produces a co-ordinated induction of key glycolytic and lipogenic genes in the liver. The transcriptional response is mediated by insulin and increased glucose oxidation, and both signals are necessary for optimal induction of FAS (fatty acid synthase). The glucose-regulated component of FAS promoter activation is mediated in part by ChREBP [ChoRE (carbohydrate response element)-binding protein], which binds to a ChoRE between −7300 and −7000 base-pairs in a carbohydrate-dependent manner. Using in vivo footprinting with nuclei from fasted and refed rats, we identify an imperfect DR-1 (direct repeat-1) element between −7110 and −7090 bp that is protected upon carbohydrate refeeding. Electrophoretic mobility-shift assays establish that this DR-1 element binds HNF-4α (hepatocyte nuclear factor 4α), and chromatin immunoprecipitation establishes that HNF-4α binding to this site is increased approx. 3-fold by glucose refeeding. HNF-4α transactivates reporter constructs containing the distal FAS promoter in a DR-1-dependent manner, and this DR-1 is required for full glucose induction of the FAS promoter in primary hepatocytes. In addition, a 3-fold knockdown of hepatocyte HNF-4α by small interfering RNA produces a corresponding decrease in FAS gene induction by glucose. Co-immunoprecipitation experiments demonstrate a physical interaction between HNF-4α and ChREBP in primary hepatocytes, further supporting an important complementary role for HNF-4α in glucose-induced activation of FAS transcription. Taken together, these observations establish for the first time that HNF-4α functions in vivo through a DR-1 element in the distal FAS promoter to enhance gene transcription following refeeding of glucose to fasted rats. The findings support the broader view that HNF-4α is an integral component of the hepatic nutrient sensing system that co-ordinates transcriptional responses to transitions between nutritional states

Polyunsaturated fatty acid suppression of fatty acid synthase (FASN): evidence for dietary modulation of NF-Y binding to the Fasn promoter by SREBP-1c

Dietary PUFAs (polyunsaturated fatty acids) co-ordinately suppress transcription of a group of hepatic genes encoding glycolytic and lipogenic enzymes. Suppression of Fasn (fatty acid synthase) transcription involves two PUFA-responsive regions, but the majority of PUFA sensitivity maps to a region within the proximal promoter containing binding sites for NF-Y (nuclear factor-Y), Sp1 (stimulatory protein 1), SREBP (sterol-regulatory-elementbinding protein), and USF (upstream stimulatory factor). Promoter activation assays indicate that altered NF-Y is the key component in regulation of Fasn promoter activity by PUFA. Using electrophoretic mobility-shift assay and chromatin immunoprecipitation analysis, we demonstrate for the first time that PUFAs decrease in vivo binding of NF-Y and SREBP-1c to the proximal promoter of the hepatic Fasn gene and the promoters of three additional genes, spot 14, stearoyl-CoA desaturase and farnesyl diphosphate synthase that are also down-regulated by PUFA. The comparable 50% decrease in NF-Y and SREBP-1c binding to the promoters of the respective PUFA-sensitive genes occurred despite no change in nuclear NF-Y content and a 4-fold decrease in SREBP-1c. Together, these findings support a mechanism whereby PUFA reciprocally regulates the binding of NF-Y and SREBP-1c to a subset of genes which share similar contiguous arrangements of sterol regulatory elements and NF-Y response elements within their promoters. PUFA-dependent regulation of SREBP-1c and NF-Y binding to this unique configuration of response elements may represent a nutrient-sensitive motif through which PUFA selectively and co-ordinately targets subsets of hepatic genes involved in lipid metabolism

Expert consensus document: Defining the major health modifiers causing atrial fibrillation: a roadmap to underpin personalized prevention and treatment

Despite remarkable advances in antiarrhythmic drugs, ablation procedures, and stroke-prevention strategies, atrial fibrillation (AF) remains an important cause of death and disability in middle-aged and elderly individuals. Unstructured management of patients with AF sharply contrasts with our detailed, although incomplete, knowledge of the mechanisms that cause AF and its complications. Altered calcium homeostasis, atrial fibrosis and ageing, ion-channel dysfunction, autonomic imbalance, fat-cell infiltration, and oxidative stress, in addition to a susceptible genetic background, contribute to the promotion, maintenance, and progression of AF. However, clinical management of patients with AF is currently guided by stroke risk parameters, AF pattern, and symptoms. In response to this apparent disconnect between the known pathophysiology of AF and clinical management, we propose a roadmap to develop a set of clinical markers that reflect the major causes of AF in patients. Thereby, the insights into the mechanisms causing AF will be transformed into a format that can underpin future personalized strategies to prevent and treat AF, ultimately informing better patient care