Transcriptional, epigenetic and metabolic signatures in cardiometabolic syndrome defined by extreme phenotypes.

BACKGROUND: This work is aimed at improving the understanding of cardiometabolic syndrome pathophysiology and its relationship with thrombosis by generating a multi-omic disease signature. METHODS/RESULTS: We combined classic plasma biochemistry and plasma biomarkers with the transcriptional and epigenetic characterisation of cell types involved in thrombosis, obtained from two extreme phenotype groups (morbidly obese and lipodystrophy) and lean individuals to identify the molecular mechanisms at play, highlighting patterns of abnormal activation in innate immune phagocytic cells. Our analyses showed that extreme phenotype groups could be distinguished from lean individuals, and from each other, across all data layers. The characterisation of the same obese group, 6 months after bariatric surgery, revealed the loss of the abnormal activation of innate immune cells previously observed. However, rather than reverting to the gene expression landscape of lean individuals, this occurred via the establishment of novel gene expression landscapes. NETosis and its control mechanisms emerge amongst the pathways that show an improvement after surgical intervention. CONCLUSIONS: We showed that the morbidly obese and lipodystrophy groups, despite some differences, shared a common cardiometabolic syndrome signature. We also showed that this could be used to discriminate, amongst the normal population, those individuals with a higher likelihood of presenting with the disease, even when not displaying the classic features.

Determination of N7-glycidamide guanine adducts in human blood DNA following exposure to dietary acrylamide using liquid chromatography/tandem mass spectrometry.

RATIONALE: Acrylamide is classified as a probable human carcinogen that is metabolised to glycidamide, which can covalently bind to DNA. The aim of this study was to investigate the formation of N7-glycidamide guanine (N7-GA-Gua) adducts in human blood DNA following exposure to acrylamide present in carbohydrate-rich foods as part of the normal human diet. METHODS: Lymphocyte DNA was extracted from blood samples obtained from healthy human volunteers. Following thermal depurination of the DNA samples, N7-GA-Gua adducts were quantified using a validated liquid chromatography/tandem mass spectrometry (LC/MS/MS) method incorporating a stable isotope labelled internal standard. Estimated dietary acrylamide intake was recorded by completion of food frequency questionnaires for the 24 hours prior to volunteer blood donation. RESULTS: An LC/MS/MS method was validated with a limit of detection of 0.25 fmol and a lower limit of quantitation of 0.50 fmol on column. N7-GA-Gua adducts were detected in human blood DNA with the levels ranging between 0.3 to 6.3 adducts per 108 nucleotides. The acrylamide intake was calculated from the food frequency questionnaires ranging between 20.0 and 78.6 µg. CONCLUSIONS: Identification and quantification of N7-GA-Gua adducts in the blood DNA of healthy volunteers suggests that dietary acrylamide exposure may lead to the formation of DNA adducts. This important finding warrants further investigation to ascertain a correlation between environmental/dietary acrylamide exposure and levels of DNA adducts.

Myotrophin is a more powerful predictor of major adverse cardiac events following acute coronary syndrome than N-terminal pro-B-type natriuretic peptide.

Myotrophin is a 12 kDa protein initially isolated from hypertrophied hearts of spontaneously hypertensive rats and acts by modulating NF-kappaB (nuclear factor kappaB) activity. We have reported previously the presence of myotrophin in patients with human systolic heart failure; however, its role as a predictor of MACE (major adverse cardiac events) in patients with ACS (acute coronary syndrome) is unclear. In the present study, we sought to investigate this and compared myotrophin with NTproBNP (N-terminal pro-B-type natriuretic peptide), a marker of MACE. We studied 356 patients with ACS {276 men; mean age, 63.0+/-12.8 years; 80.6% STEMI [ST segment elevation MI (myocardial infarction)]; and 19.4% NSTEMI (non-STEMI)}. Blood measurement was made at 25-48 h after the onset of chest pain. The plasma concentration of myotrophin and NTproBNP was determined using in-house non-competitive immunoassays. Patients were followed-up for the combined end point of death, MI or need for urgent revascularization. Over the median follow-up period of 355 (range 0-645) days, there were 28 deaths, 27 non-fatal MIs and 73 patients required urgent revascularization. Myotrophin was raised in patients with MACE compared with survivors [510.7 (116.0-7445.6) fmol/ml compared with 371.5 (51.8-6990.4) fmol/ml respectively; P=0.001; values are medians (range)]. Using a Cox proportional hazards model, myotrophin {HR (hazard ratio), 1.64 [95% CI (confidence interval), 0.97-2.76]; P=0.05} and Killip class above 1 [HR, 1.52 (95% CI, 0.93-2.42); P=0.10] were the only independent predictors of MACE. A Kaplan-Meier survival curve revealed a significantly better clinical outcome in patients with myotrophin below the median compared with those with myotrophin above the median (log rank, 7.63; P=0.006). In conclusion, after an ACS, levels of myotrophin are more informative at predicting MACE than NTproBNP and may be useful to risk stratify patients.

Advanced glycation end products stimulate an enhanced neutrophil respiratory burst mediated through the activation of cytosolic phospholipase A2 and generation of arachidonic Acid.

BACKGROUND: Advanced glycation end products (AGEs) enhance NADPH oxidase, and hence respiratory burst activity, of stimulated neutrophils. They are thus potentially vasculopathic, especially in diabetes, uremia, and aging, in which AGEs classically accumulate. We investigated the underlying mechanisms. METHODS AND RESULTS: Neutrophils prelabeled with [3H]arachidonic acid display increased [3H]arachidonate release on exposure to AGE-albumin over exposure to albumin alone (by 151+/-16%, P<0.01). Arachidonic acid (AA) itself seems to mediate the AGE-augmented neutrophil respiratory burst (ascertained by chemiluminescence). Inhibitors of the cyclooxygenase pathway (indomethacin) and lipoxygenase pathway (MK-886) do not impair this AGE effect, excluding a contribution from AA metabolites. Cytosolic phospholipase A2 (cPLA2) controls AA generation. Its inhibition by methyl arachidonyl fluorophosphonate abrogates the AGE-enhanced activated neutrophil respiratory burst, and it is demonstrably stimulated in AGE-exposed neutrophils, as evidenced by isoform gel-shift and an increasingly membrane-translocated state in Western blots of neutrophil subfractions. Inhibition of other PLA2 isoforms, secretory PLA2 and calcium-independent PLA2, by manoalide and haloenol-lactone suicide substrate, respectively, does not affect this effect of AGEs relative to inhibitor-treated controls. The thiol antioxidant NAC reduces activation of cPLA2 (assessed by isoform gel-shift and membrane translocation), production of AA in AGE-albumin-exposed neutrophils (H3 release reduced to 104+/-17%, P=0.94 compared with albumin-exposed neutrophils), and the AGE-augmented neutrophil respiratory burst. CONCLUSIONS: AGE augmentation of the activated neutrophil respiratory burst requires AA generation, through which neutrophil NADPH oxidase may be upregulated, enhancing reactive oxygen species output. AA is generated by cPLA2, which may be stimulated through an AGE-activated redox-sensitive pathway.