Multiple novel prostate cancer susceptibility signals identified by fine-mapping of known risk loci among Europeans

Genome-wide association studies (GWAS) have identified numerous common prostate cancer (PrCa) susceptibility loci. We have fine-mapped 64 GWAS regions known at the conclusion of the iCOGS study using large-scale genotyping and imputation in 25 723 PrCa cases and 26 274 controls of European ancestry. We detected evidence for multiple independent signals at 16 regions, 12 of which contained additional newly identified significant associations. A single signal comprising a spectrum of correlated variation was observed at 39 regions; 35 of which are now described by a novel more significantly associated lead SNP, while the originally reported variant remained as the lead SNP only in 4 regions. We also confirmed two association signals in Europeans that had been previously reported only in East-Asian GWAS. Based on statistical evidence and linkage disequilibrium (LD) structure, we have curated and narrowed down the list of the most likely candidate causal variants for each region. Functional annotation using data from ENCODE filtered for PrCa cell lines and eQTL analysis demonstrated significant enrichment for overlap with bio-features within this set. By incorporating the novel risk variants identified here alongside the refined data for existing association signals, we estimate that these loci now explain ∼38.9% of the familial relative risk of PrCa, an 8.9% improvement over the previously reported GWAS tag SNPs. This suggests that a significant fraction of the heritability of PrCa may have been hidden during the discovery phase of GWAS, in particular due to the presence of multiple independent signals within the same regio

The development and validation of a scoring tool to predict the operative duration of elective laparoscopic cholecystectomy

Background: The ability to accurately predict operative duration has the potential to optimise theatre efficiency and utilisation, thus reducing costs and increasing staff and patient satisfaction. With laparoscopic cholecystectomy being one of the most commonly performed procedures worldwide, a tool to predict operative duration could be extremely beneficial to healthcare organisations. Methods: Data collected from the CholeS study on patients undergoing cholecystectomy in UK and Irish hospitals between 04/2014 and 05/2014 were used to study operative duration. A multivariable binary logistic regression model was produced in order to identify significant independent predictors of long (> 90 min) operations. The resulting model was converted to a risk score, which was subsequently validated on second cohort of patients using ROC curves. Results: After exclusions, data were available for 7227 patients in the derivation (CholeS) cohort. The median operative duration was 60 min (interquartile range 45–85), with 17.7% of operations lasting longer than 90 min. Ten factors were found to be significant independent predictors of operative durations > 90 min, including ASA, age, previous surgical admissions, BMI, gallbladder wall thickness and CBD diameter. A risk score was then produced from these factors, and applied to a cohort of 2405 patients from a tertiary centre for external validation. This returned an area under the ROC curve of 0.708 (SE = 0.013, p  90 min increasing more than eightfold from 5.1 to 41.8% in the extremes of the score. Conclusion: The scoring tool produced in this study was found to be significantly predictive of long operative durations on validation in an external cohort. As such, the tool may have the potential to enable organisations to better organise theatre lists and deliver greater efficiencies in care

Age Related Bioenergetics Profiles in Isolated Rat Cardiomyocytes Using Extracellular Flux Analyses.

Mitochondrial dysfunction is increasingly recognized and studied as a mediator of heart disease. Extracellular flux analysis (XF) has emerged as a powerful tool to investigate cellular bioenergetics in the context of cardiac health and disease, however its use and interpretation requires improved understanding of the normal metabolic differences in cardiomyocytes (CM) at various stages of maturation. This study standardized XF analyses methods (mitochondrial stress test, glycolytic stress test and palmitate oxidation test) and established age related differences in bioenergetics profiles of healthy CMs at newborn (NB1), weaning (3WK), adult (10WK) and aged (12-18MO) time points. Findings show that immature CMs demonstrate a more robust and sustained glycolytic capacity and a relative inability to oxidize fatty acids when compared to older CMs. The study also highlights the need to recognize the contribution of CO2 from the Krebs cycle as well as lactate from anaerobic glycolysis to the proton production rate before interpreting glycolytic capacity in CMs. Overall, this study demonstrates that caution should be taken to assure that translatable developmental time points are used to investigate mitochondrial dysfunction as a cause of cardiac disease. Specifically, XF analysis of newborn CMs should be reserved to study fetal/neonatal disease and older CMs (≥10 weeks) should be used to investigate adult disease pathogenesis. Knowledge gained will aid in improved investigation of developmentally programmed heart disease and stress the importance of discerning maturational differences in bioenergetics when developing mitochondrial targeted preventative and therapeutic strategies for cardiac disease

Mitochondrial stress test of cardiomyocytes at various maturational ages.

<p>XF trace (A) and bar graph (B) illustrates OCR changes (from baseline) in NB1, 3WK, 10WK, and 12–18MNTH CMs during mitochondrial stress testing. For group comparisons OCR was normalized to baseline prior to addition of Oligomycin, FCCP and Rotenone/Antimycin A where indicated. Respiratory control ratio (C) and coupling efficiency (D) as calculated from traces are compared between groups. Data are expressed as means ± SEM of 4–7 independent experiments. *p<0.05 by one-way ANOVA and Tukey’s post-test.</p

XF Analyses of Isolated Cardiomyocytes.

<p>Examples of real-time trace oxygen consumption rate (OCR) and extracellular acidification rate (ECAR) during extracellular flux analyses using (A) mitochondrial stress test, (B) glycolytic stress test and (C) palmitate oxidation test. Data points represent mean of three readings taken at each time-point. Drug injections are shown for each test and boxes visually depict computed data.</p

Palmitate oxidation test of cardiomyocytes at various maturational ages.

<p>OCR was measured in NB1, 3WK, 10WK, and 12–18MNTH CMs and normalized to baseline rates to interrogate differences in response among the groups. OCR response to exogenous Palmitate-BSA and Etomoxir (carnitine palmitoyl transport inhibitor) are illustrated in trace (A). Bar graphs illustrate group differences in OCR response from baseline conditions (B). Data are expressed as means ± SEM of 3–4 independent experiments. *p<0.05 by one-way ANOVA and Tukey’s post-test.</p

Proton production rate during palmitate oxidation test.

<p>The positive or notionally negative contribution of lactate from both anaerobic glycolysis (grey) and from CO₂/respiration (white) to the sum (black) proton production rate (PPR) are demonstrated for cardiomyocytes from each maturational time-point. The PPR is demonstrated in response to palmitate (A) and etomoxir (B). Data shown are means ± SEM of 3–5 independent experiments. *p<0.05 by one way ANOVA and Tukey’s post-test.</p

Glycolysis stress test of cardiomyocytes at various maturational ages.

<p>Extra-cellular acidification rate (ECAR) traces (A) and bar graphs (B) show the glycolytic response of NB1, 3WK, 10WK and 12–18MTH old cardiomyocytes in response to glucose and oligomycin injection where indicated. Data shown are means ± SEM of 3–5 independent experiments. *p<0.05 by one way ANOVA and Tukey’s post-test.</p

Proton production rate during glycolytic stress test.

<p>The positive or notionally negative contribution of lactate from both anaerobic glycolysis (grey) and from CO₂/respiration (white) to the sum (black) proton production rate (PPR) are demonstrated for cardiomyocytes from each maturational time-point. The PPR is demonstrated in response to glucose (A) and oligomycin (B). Data shown are means ± SEM of 3–5 independent experiments. *p<0.05 by one way ANOVA and Tukey’s post-test.</p