Citations

Abstract BackgroundCopy number variants (CNVs) are pervasive in the human genome but potential disease associations with rare CNVs have not been comprehensively assessed in large datasets. We analysed rare CNVs in genes and non-coding regions for 86,788 breast cancer cases and 76,122 controls of European ancestry with genome-wide array data.ResultsGene burden tests detected the strongest association for deletions in BRCA1 (P= 3.7E-18). Nine other genes were associated with a p-value < 0.01 including known susceptibility genes CHEK2 (P= 0.0008), ATM (P= 0.002) and BRCA2 (P= 0.008). Outside the known genes we detected associations with p-values < 0.001 for either overall or subtype-specific breast cancer at nine deletion regions and four duplication regions. Three of the deletion regions were in established common susceptibility loci.ConclusionsThis is the first genome-wide analysis of rare CNVs in a large breast cancer case-control dataset. We detected associations with exonic deletions in established breast cancer susceptibility genes. We also detected suggestive associations with non-coding CNVs in known and novel loci with large effects sizes. Larger sample sizes will be required to reach robust levels of statistical significance.

The well-balanced secretion between insulin and growth hormone (GH) is essential in regulating substrate metabolism, energy metabolism, and body composition. High insulin and low GH levels are often observed in obesity, contributing to reduced energy expenditure and further fat accumulation. Although suppression of hyperinsulinemia is proposed as a treatment for obesity, changes in GH secretion and energy metabolism following this treatment are not thoroughly studied. This leaves unexplained observations, such as unchanged lean mass following insulin reduction. In this study, high-fat diet-induced obese (DIO) and normal chow-fed lean mice on a C57BL/6J background were treated for 7 weeks with diazoxide (1250 mg/kg in food), a K ATP channel opener that suppressed insulin secretion. Diazoxide treatment for 10 days was sufficient to increase pulsatile GH secretion in DIO mice before any significant body weight change. The restored insulin-GH balance in DIO mice was followed by improvement in substrate and energy metabolism in a prolonged treatment period (4–6 weeks), including reduced fat mass, increased lipid oxidation and energy expenditure, as well as improved insulin sensitivity and metabolic flexibility. These metabolic benefits occurred along with the changes in the expression level of genes regulated by the insulin-GH balance. When applying diazoxide to normal chow-fed normoinsulinemic lean mice, none of the above metabolic effects was observed, suggesting that the metabolic changes following diazoxide treatment were mediated through the suppression of hyperinsulinemia. These results suggest that suppression of hyperinsulinemia by diazoxide restores GH secretion and improves substrate and energy metabolism in DIO mice.

Introduction: Ischemic stroke (IS) causes substantial morbidity and mortality in patients undergoing percutaneous coronary intervention (PCI) with a 5 yr incidence ~ 3%. We sought the test the accuracy of Machine learning (ML) algorithms in predicting IS in patients undergoing PCI. Methods: Mayo Clinic CathPCI registry data were retrospectively analyzed from Jan 2003 - June 2018 including 21,872 patients who underwent PCI. The cohort was randomly divided into a training sample (75%, n=16404) and a unique test sample (25%, n=5468) prior to model generation. The risk prediction model was generated utilizing a random forest algorithm (RF model) on 188 unique variables to predict the risk of IS at 6-month, 1, 2, and 5-year post PCI. Conventional risk factors for stroke were used for logistic regression. The receiver operating characteristic (ROC) curve and area under the curve for the RF and logistic regression models were compared for the test cohort. Results: The mean age was 66.9 ± 12.4 years, and 71% were male. Patient demographics and outcomes are shown in Table 1 . The ROC area under the curve for the RF model was superior compared to the logistic regression model in predicting IS at 6 months, 1,2 and 5 yrs for the test cohort ( Figure 1 .) Conclusions: The RF model accurately predicts short and long term risk of IS and outperforms logistic regression analysis in patients undergoing PCI.

Sarcoplasmic reticulum (SR) Ca 2+ release and reuptake are important mechanisms in airway smooth muscle (ASM) intracellular Ca 2+ [Ca 2+ ] i regulation. In other tissues, there is increasing evidence for a role of mitochondria in [Ca 2+ ] i buffering, especially following SR Ca 2+ release. Mitochondrial buffering may also influence Ca 2+ influx. The purpose of the present study was to examine the role of mitochondria in [Ca 2+ ] i buffering in human ASM. Cells were loaded with fura‐2 and exposed to 10 µM histamine in "0" Ca 2+ HBSS containing 1mM lanthanum and 1µM nifedipine (to block Ca 2+ influx/efflux) and in the additional presence of 1µM RU360 (mitochondrial Ca 2+ uniporter inhibitor) or 1µM CGP37157 (CGP; mitochondrial Na + /Ca 2+ exchange inhibitor). Compared to controls, peak [Ca 2+ ] i levels were increased by 30% in the presence of CGP, while RU360 had not effect. Both CGP and RU360 significantly increased store‐operated Ca 2+ entry. In cells co‐loaded with fura‐2 and rhod‐2 (mitochondrial Ca 2+ indicator), exposure to 5 µM caffeine showed instantaneous SR Ca 2+ release followed by an increase in [Ca 2+ ] mito . Exposure to 1 µM ACh resulted in ACh‐induced [Ca 2+ ] i oscillations that were reflected by mitochondria (but with a time delay). In ASM cells co‐labeled for mitochondria (MitoTracker) and SR (fluorescent ryanodine) migration of mitochondria towards SR was observed upon exposure to ACh or cyclopiazonic acid. This migration was completely inhibited by phalloidin (actin inhibitor). These data demonstrate an important role of mitochondria in [Ca 2+ ] i buffering in ASM. Supported by NIH grant RR024150, and the Flight Attendants Medical Research Institute (FAMRI). Additional funding from the Department of Anesthesiology, Mayo Clinic.

Introduction: Although alterations in mitochondrial function have been observed in senescent hearts, the molecular basis for aging-associated decline in energy metabolism in the human heart is not fully understood. Objective: To determine aging-related changes in functional activity and protein expression level of mitochondrial oxidative phosphorylation (OXPHOS) complexes and expression of genes regulating mitochondrial energetics in the human heart. Methods: Right atrial appendages from well-matched adult (29-57 y.o., n=19) and aged (65-85 y.o., n=22) patients undergoing elective CABG surgery were used. Functional activity of OXPHOS complexes was measured spectrophotometrically. Protein expression level of corresponding OXPHOS protein subunits was determined by Western blot. Gene expression profiling was performed using Affymetrix Human Genome U133 Plus 2.0 microarrays. Results: Mitochondria from senescent hearts demonstrated a significant decrease in complex I and V functional activity without significant changes in the rest of the complexes (Fig. A). At the protein expression level, there was reduction in complex I, III, and IV (Fig. B). This was associated with downregulation of the majority (86%, 90 of 105) of genes coding mitochondrial proteins (Fig. C). Forty-six percent (41 of 90) of the downregulated genes were confined to pathways regulating mitochondrial energetics. Conclusion: With aging, the functional activity of OXPHOS is reduced due to supression of protein expression and downregulation of genes regulating mitochondrial energetics. This provides a substrate for reduced energetic efficiency associated with senescence in the human atria.

Objective To compare the prevalence and patterns of anomalous coronary artery origin from the opposite sinus (ACAOS) in patients with bicuspid aortic valve (BAV) and tricuspid aortic valve (TAV). Methods Retrospective review of consecutive patients with surgically excised BAV and TAV was performed from 1994 to 2015. Clinical notes, echocardiograms, coronary angiograms, CT angiographies, and pathology reports were reviewed. ACAOS included right coronary artery from the left cusp, left circumflex artery from the right cusp and left main or left anterior descending artery from the right cusp. Results 2371 (years 1994–2015) and 1679 (years 2009–2015) consecutive patients with pathology-confirmed BAV and TAV, respectively, and defined preoperative coronary anatomy were identified. A left dominant coronary circulation was present in 386 (18%) patients with BAV and 179 (11%) patients with TAV (p<0.001). ACAOS was identified in 43 (1.8%) patients with BAV and 15 (0.9%) patients with TAV, p=0.02. Among patients with BAV and ACAOS, the most common phenotype was right-left fusion (n=34, 79%) with present raphe (n=36, 84%), with no association between BAV phenotype and ACAOS type. On multivariate analysis, BAV status and size of the mid-ascending aorta were independently associated with ACAOS (OR 3.29; CI 1.26 to 8.6; p=0.02; OR 0.93; CI 0.87 to 0.98; p=0.01; respectively). Only two patients with ACAOS, one with BAV and one with TAV, had a perioperative coronary ischaemic event. Conclusions The prevalence of the potentially malignant ACAOS is significantly higher (threefold higher odds) in patients with BAV as compared with TAV, yet remains uncommon in absolute terms. Most patients with BAV and ACAOS had right-left cusp fusion and present raphe. Perioperative coronary events are rare in patients with ACAOS.

The antihypertensive influence of fish oil is controversial, and mechanisms remain unclear. We tested the hypothesis that fish oil reduces mean arterial pressure (MAP) via reductions in muscle sympathetic nerve activity (MSNA). Because the inverse relation between fish oil and hypertension appears to be dependent on the degree of hypertension, we also tested the hypothesis that fish oil would elicit more dramatic reductions in MAP and MSNA in prehypertensive (PHT) compared to normotensive (NT) subjects. Resting MAP, MSNA, and heart rate (HR) were examined before and after 8 wk of fish oil (9g/day) or placebo (olive oil; 9g/day) in 38 NT (19 fish oil; 19 placebo) and 29 PHT (15 fish oil; 14 placebo) volunteers. Fish oil did not alter resting MAP, MSNA, or HR in either NT (71±2 to 71±2 mmHg; 11±2 to 10±1 bursts/min; 80±1 to 80±1 beats/min) or PHT (88±2 to 87±1 mmHg; 11±2 to 10±2 bursts/min; 73±2 to 73±2 beats/min) subjects. However, when NT and PHT groups were consolidated, a significant correlation was observed between changes in MAP and changes in MSNA in the fish oil group (r=0.354, p=0.035). In conclusion, fish oil did not alter neural cardiovascular control in NT or PHT. However, interindividual MAP responses to fish oil appear to be moderately associated with changes in MSNA, suggesting that the sympathetic nervous system may contribute to the inconsistent antihypertensive response of fish oil. Supported by NIH (HL‐088689).

Omega‐3 fatty acids found in fish oil have been suggested to protect against cardiovascular disease, yet underlying mechanisms remain unclear. Given the well documented links between mental stress (MS) and cardiovascular risk, we hypothesized that fish oil would blunt blood pressure (BP), heart rate (HR), and muscle sympathetic nerve activity (MSNA) responsiveness to MS. Neural and cardiovascular responses to a 5 min mental arithmetic protocol were recorded in 67 non‐hypertensive subjects before and after 8 wks of fish oil (9g/day; n=33) or placebo (olive oil; 9g/day; n=34). Fish oil blunted HR reactivity to MS (group × condition × time interaction, P=0.012), but did not alter BP reactivity (interactions, P>;0.05). Fish oil blunted total MSNA reactivity to MS (interaction, P=0.039), but did not alter MSNA burst frequency and burst incidence reactivity (interactions, P>;0.05). Finally, fish oil significantly blunted calf vascular conductance (CVC) reactivity to MS (interaction, P=0.013), but did not alter forearm vascular conductance reactivity (interaction, P>;0.05). In conclusion, 8 wks of fish oil supplementation significantly attenuated HR and total MSNA reactivity to MS, and elicited a paradoxical blunting of CVC. These findings support and extend the growing evidence that fish oil may have positive health benefits regarding neural cardiovascular control in humans. Supported by NIH (HL‐088689).

The impact of diet on the microbial composition in the gastrointestinal tract has been well documented. However, quantitation of the role of diet in shaping microbial composition has been difficult due to the presence of factors such as host genetics and environment. We used two genetically identical pigs housed together as a system for isolating diet‐induced changes in the microbiome. We used a withdrawal design across four 14‐d periods with two diets having different solubility of dietary fiber to study the fecal microbial community by 454‐pyrosequencing of the 16S rRNA gene. Shifts in the fecal microbial community composition were assessed with respect to dietary correlations. Similarity analysis revealed that the gut microbiomes from the two different diets clustered separately. Taxa‐based approaches detected significantly different bacteria composition in two different diets. Diversity analysis showed that bacterial diversity was associated with the level of dietary fiber solubility. To conclude, the impact of diet on gut microbiome composition was isolated from host genetics and environment. Diet‐induced changes in gut microbiome composition were observed and found to be reversible within a short time. Our results show that genetically identical pigs can be used as a model system for assessing the influence of diet and other variables on the composition of the gut microbial community. Grant Funding Source : University of Illinois Agricultural Experiment Station, USDA AG 2008–34480‐19328, USDA AG 2008–34480‐19328, USDA/ARS AG 58–5438‐7–317l, USDA/ARS AG 58–5438‐2–307