UTILITY OF ULTRASOUND VERSUS GENE EXPRESSION CLASSIFIER IN THYROID NODULES WITH ATYPIA OF UNDETERMINED SIGNIFICANCE.

OBJECTIVE: Thyroid nodules with fine-needle aspiration (FNA) cytology categorized as atypia of undetermined significance (AUS) often undergo additional diagnostic analysis with the Afirma Gene Expression Classifier (GEC), which classifies these as either high probability of being benign (GEC-B) or suspicious for malignancy (GEC-S). Our goal was to assess the clinical validity and utility of GEC in the evaluation of AUS cytology and evaluate the performance of ultrasonography (USG) for predicting malignancy in this subset. METHODS: We conducted a study with a retrospective cohort of patients from January 2012 to January 2014 who had FNA of thyroid nodules >1 cm in size with AUS cytology. RESULTS: Cleveland Clinic Florida has an overall prevalence of AUS of 5%. A total of 119 cases with nodules >1 cm in size were reported as AUS. Forty-eight (40.3%) had a GEC performed after the first FNA (AUS-1), and 27 of these were GEC-S. Of those 27, 21 went for surgery and 14 (66.6%) had thyroid cancer on histopathology. The remaining 71 with AUS-1 were sent for a second FNA: 19 nodules were benign and did not undergo further evaluation, while the remaining 52 were reported as AUS for the second consecutive time (AUS-2). AUS-2 samples were sent for GEC. Of these 52 AUS-2, 38 (73.1%) were reported as GEC-S. Thirty-five went for surgery and 32 (91.4%) had confirmed malignancy on histopathology. Positive predictive value (PPV) was 91.4% for AUS-2 and 66.6% for AUS-1. Moreover, AUS-2 nodules that were hypoechoic and solid on USG showed a PPV of 92% for malignancy. CONCLUSION: In our practice, the diagnostic accuracy to predict malignancy with GEC for AUS-1 nodules was poor (PPV, 66.6%). The PPV of GEC testing was markedly higher at 91.4% performed after two consecutive AUS cytologies. AUS-2 nodules that were solid and hypoechoic on USG also had a high probability to be malignant (PPV, 92%). We recommend repeat FNA on AUS-1 nodules rather than proceeding directly to GEC testing. Also, we suggest that among AUS-2 nodules, surgery can be recommended when USG shows solid and hypoechoic features with GEC testing reserved for the remainder. ABBREVIATIONS: AUS = atypia of undetermined significance FNA = fine-needle aspiration GEC = gene expression classifier GEC-B = GEC-benign GEC-S = GEC-suspicious for malignancy NPV = negative predictive value PPV = positive predictive value USG = ultrasonography.

An afferent vagal nerve pathway links hepatic PPARalpha activation to glucocorticoid-induced insulin resistance and hypertension.

Glucocorticoid excess causes insulin resistance and hypertension. Hepatic expression of PPARalpha (Ppara) is required for glucocorticoid-induced insulin resistance. Here we demonstrate that afferent fibers of the vagus nerve interface with hepatic Ppara expression to disrupt blood pressure and glucose homeostasis in response to glucocorticoids. Selective hepatic vagotomy decreased hyperglycemia, hyperinsulinemia, hepatic insulin resistance, Ppara expression, and phosphoenolpyruvate carboxykinase (PEPCK) enzyme activity in dexamethasone-treated Ppara(+/+) mice. Selective vagotomy also decreased blood pressure, adrenergic tone, renin activity, and urinary sodium retention in these mice. Hepatic reconstitution of Ppara in nondiabetic, normotensive dexamethasone-treated PPARalpha null mice increased glucose, insulin, hepatic PEPCK enzyme activity, blood pressure, and renin activity in sham-operated animals but not hepatic-vagotomized animals. Disruption of vagal afferent fibers by chemical or surgical means prevented glucocorticoid-induced metabolic derangements. We conclude that a dynamic interaction between hepatic Ppara expression and a vagal afferent pathway is essential for glucocorticoid induction of diabetes and hypertension.

Vascular respiratory uncoupling increases blood pressure and atherosclerosis.

The observations that atherosclerosis often occurs in non-smokers without elevated levels of low-density lipoprotein cholesterol, and that most atherosclerosis loci so far identified in mice do not affect systemic risk factors associated with atherosclerosis, suggest that as-yet-unidentified mechanisms must contribute to vascular disease. Arterial walls undergo regional disturbances of metabolism that include the uncoupling of respiration and oxidative phosphorylation, a process that occurs to some extent in all cells and may be characteristic of blood vessels being predisposed to the development of atherosclerosis. To test the hypothesis that inefficient metabolism in blood vessels promotes vascular disease, we generated mice with doxycycline-inducible expression of uncoupling protein-1 (UCP1) in the artery wall. Here we show that UCP1 expression in aortic smooth muscle cells causes hypertension and increases dietary atherosclerosis without affecting cholesterol levels. UCP1 expression also increases superoxide production and decreases the availability of nitric oxide, evidence of oxidative stress. These results provide proof of principle that inefficient metabolism in blood vessels can cause vascular disease.

Endothelial Lipase: a key player in HDL metabolism modulates inflammation and atherosclerotic risk.

Endothelial Lipase (EL) is a newly identified member of the triacylglycerol lipase family. Recent studies suggested that EL may be an important determinant of HDL-metabolism and inflammation acting at the level of the vessel wall. The aim of this review is to summarize important facts derived from experimental approaches and from epidemiologic human studies to provide a comprehensive view on the role of EL in inflammation and atherogenesis as well as target for potential pharmaceutical interventions.