Metabolic Profiling of Adiponectin Levels in Adults

Background - Adiponectin, a circulating adipocyte-derived protein, has insulin-sensitizing, anti-inflammatory, antiatherogenic, and cardiomyocyte-protective properties in animal models. However, the systemic effects of adiponectin in humans are unknown. Our aims were to define the metabolic profile associated with higher blood adiponectin concentration and investigate whether variation in adiponectin concentration affects the systemic metabolic profile. Methods and Results - We applied multivariable regression in ≤5909 adults and Mendelian randomization (using cis-acting genetic variants in the vicinity of the adiponectin gene as instrumental variables) for analyzing the causal effect of adiponectin in the metabolic profile of ≤37 545 adults. Participants were largely European from 6 longitudinal studies and 1 genome-wide association consortium. In the multivariable regression analyses, higher circulating adiponectin was associated with higher high-density lipoprotein lipids and lower very-low-density lipoprotein lipids, glucose levels, branched-chain amino acids, and inflammatory markers. However, these findings were not supported by Mendelian randomization analyses for most metabolites. Findings were consistent between sexes and after excluding high-risk groups (defined by age and occurrence of previous cardiovascular event) and 1 study with admixed population. Conclusions - Our findings indicate that blood adiponectin concentration is more likely to be an epiphenomenon in the context of metabolic disease than a key determinant

HOXA methylation in normal endometrium from premenopausal women is associated with the presence of ovarian cancer: A proof of principle study

DNA methylation of polycomb group target (PCGT) genes is an early step in carcinogenesis and could potentially be assayed to determine cancer risk prediction. To assess whether methylation changes in PCGT genes in normal tissue is able to predict the presence of cancer, we studied HOXA gene methylation in normal endometrium from premenopausal ovarian cancer patients and age-matched healthy controls without ovarian cancer. DNA methylation of HOXA9 and HOXA11 genes in normal endometrium was associated with ovarian cancer in an initial test set and this was subsequently confirmed in independent validation sample sets. The overall risk of ovarian cancer was increased 12.3-fold by high HOXA9 methylation for all stages, and 14.8-fold for early stage ovarian cancers, independent of age, phase of the menstrual cycle and histology of the cancer. The results of this proof of principle study demonstrate the potential to detect ovarian cancer via analysis of normal endometrial cells and provide insight into the possible contribution of this novel approach in ovarian cancer risk prediction and prevention. (C) 2009 UIC

Decreased serum thrombospondin-1 levels in pancreatic ductal adenocarcinoma patients: an early indicator of disease or diabetes mellitus development?

Introduction: Identification of serum biomarkers enabling earlier diagnosis of pancreatic ductal adenocarcinoma (PDAC) could improve outcome. Aims: Serum protein profiles in patients with pre-clinical disease and at diagnosis were investigated. Patients & methods: Serum from cases up to 4 years prior to diagnosis of PDAC and controls enrolled on the UK Collaborative Trial of Ovarian Cancer Screening (UKCTOCS, n=174) were studied, alongside samples from patients diagnosed with PDAC, chronic pancreatitis, benign biliary disease and from healthy subjects (n=199). Isobaric tags for relative and absolute quantification (iTRAQ) enabled comparisons of pooled serum from a test set (n=150). Validation was undertaken using multiple reaction monitoring (MRM) and/or western blotting in all 373 human samples and in a KPC mouse model. Results: iTRAQ identified thrombospondin-1 (TSP-1) as down-regulated pre-clinically and in diagnosed patients. MRM confirmed significant down-regulation of TSP-1 up to 24 months prior to diagnosis. A combination of TSP-1 and CA19-9 (AUC= 0.86), significantly outperformed both markers alone (0.69 & 0.77 respectively). TSP-1 was also decreased in PDAC patients compared to healthy controls (P<0.05), patients with benign biliary obstruction (P<0.01) and in serum of KPC mice with PDAC. Low levels of TSP-1 correlated with poorer survival pre-clinically (P<0.05) and at diagnosis (P<0.02). Reduced TSP-1 levels were observed in PDAC patients with a confirmed diabetes mellitus (P<0.04). The decrease in TSP-1 compared to healthy controls was only observed in PDAC patients with diabetes (P<0.009). Conclusion: Circulating TSP-1 levels decrease during the development of PDAC. The influence of diabetes mellitus on biomarker behavior should be considered in future studies