Genetic architecture of DCC and influence on psychological, psychiatric and cardiometabolic traits in multiple ancestry groups in UK Biobank

BACKGROUND

People with severe mental illness have a higher risk of cardiometabolic disease than the general population. Traditionally attributed to sociodemographic, behavioural factors and medication effects, recent genetic studies have provided evidence of shared biological mechanisms underlying mental illness and cardiometabolic disease. We aimed to determine whether signals in the DCC locus, implicated in psychiatric and cardiometabolic traits, were shared or distinct.

METHODS

In UK Biobank, we systematically assessed genetic variation in the DCC locus for association with metabolic, cardiovascular and psychiatric-related traits in unrelated "white British" participants (N = 402,837). Logistic or linear regression were applied assuming an additive genetic model and adjusting for age, sex, genotyping chip and population structure. Bonferroni correction for the number of independent variants was applied. Conditional analyses (including lead variants as covariates) and trans-ancestry analyses were used to investigate linkage disequilibrium between signals.

RESULTS

Significant associations were observed between DCC variants and smoking, anhedonia, body mass index (BMI), neuroticism and mood instability. Conditional analyses and linkage disequilibrium structure suggested signals for smoking and BMI were distinct from each other and the mood traits, whilst individual mood traits were inter-related in a complex manner.

LIMITATIONS

Restricting analyses in non-"white British" individuals to the phenotypes significant in the "white British" sample is not ideal, but the smaller samples sizes restricted the phenotypes possible to analyse.

CONCLUSIONS

Genetic variation in the DCC locus had distinct effects on BMI, smoking and mood traits, and therefore is unlikely to contribute to shared mechanisms underpinning mental and cardiometabolic traits.

172Coronary 18F-sodium fluoride uptake predicts progression of coronary arterial calcification

Background

Combined positron emission tomography and computed tomography (PET-CT) using 18F-sodium fluoride (18F-NaF) to detect microcalcification provides the opportunity to gain important insights into disease activity in coronary atherosclerosis. However, the relationship between 18F-NaF uptake and progression of coronary calcification has not been determined.

Purpose

To determine the relationship between 18F-NaF uptake and progression of coronary calcification in patients with clinically stable coronary artery disease (CAD).

Methods

Patients with established, multivessel CAD underwent 18F-NaF PET-CT and CT coronary calcium scoring at baseline, with repeat CT calcium scoring at one year. Coronary arterial PET uptake was analysed qualitatively and semi-quantitatively in diseased vessels by measuring maximum tissue-to-background ratio (TBRmax) – defined as the maximum standardised uptake value in a plaque divided by mean blood pool activity measured in the right atrium. Coronary calcification was quantified by measuring calcium mass, volume, average calcium density and total Agatston score (AU).

Results

In total, 185 patients underwent baseline and repeat imaging (median age 66 years, 80% men), and 118 (64%) had increased 18F-NaF uptake in at least one vessel. Median total calcium score, volume, mass and average density were higher in patients with compared to those without increased 18F-NaF uptake (Table 1). At one year, patients with evidence of increased 18F-NaF uptake demonstrated more rapid progression of coronary calcification (97 [39–166] AU) versus those without uptake (35 [7–93] AU; p<0.0001). Amongst 18F-NaF-positive patients, the calcium score increased only in coronary segments with 18F-NaF uptake (baseline 90.5 [27.5–202] AU versus one year 135.5 [59.3–281.8] AU; p<0.0001) and not in 18F-NaF-negative segments (baseline 44.5 [16–110.5] AU versus one year 46.5 [18.25–114] AU; p=0.446). There was a moderate correlation between TBRmax and change in total calcium score, volume and mass at 1 year (Spearman's Rho = 0.37, 0.38, 0.46 respectively; p<0.0001 for all).

Coronary calcification at baseline in PET-negative and PET-positive patients All patients (n=185) 18F-NaF Positive (n=118) 18F-NaF Negative (n=67) P value Agatston Score (AU) 381 [107–892] 541 [245–1130] 136 [55–361] p<0.0001 Calcium Volume (mm3) 358 [131–787] 506 [251–1014] 131 [64–343] p<0.0001 Calcium Mass (mg) 71 [23–155] 100 [48–222] 24 [11–69] p<0.0001 Average Density (mg/mm3) 0.19 [0.17–0.22] 0.20 [0.18–0.23] 0.18 [0.16–0.20] p<0.0001

Conclusions

Coronary 18F-NaF uptake identifies both patients and individual coronary segments with greater disease and more rapid progression of coronary calcification over one year.

Acknowledgement/Funding

AstraZeneca (unrestricted educational grant). British Heart Foundation (CH/09/002, RE/13/3/30183, FS/17/79/33226) Wellcome Trust (WT103782AIA).

1269Dual antiplatelet therapy to inhibit myocardial injury in patients with high-risk coronary artery plaque: a randomized controlled trial

Background

High-risk coronary atherosclerotic plaque is associated with higher plasma troponin concentrations suggesting ongoing myocardial injury that may be a target for dual antiplatelet therapy.

Purpose

To determine whether ticagrelor reduces high-sensitivity troponin I concentrations in patients with established coronary artery disease and high-risk coronary plaque with 18F-fluoride uptake.

Methods

In a randomized double-blind placebo-controlled trial, patients with multivessel coronary artery disease underwent coronary 18F-fluoride positron emission tomography-computed tomography and measurement of high-sensitivity cardiac troponin I and were randomized (1:1) to ticagrelor 90 mg twice daily or matched placebo. The primary endpoint was troponin I concentration at 30 days in patients with increased coronary 18F-fluoride uptake.

Results

In total, 202 patients were randomized and 191 met the pre-specified criteria for inclusion in the primary analysis. In patients with increased coronary 18F-fluoride uptake (n=120/191) there was no evidence that ticagrelor had an effect on plasma troponin concentrationsat 30 days (ratio of geometric means for ticagrelor versusplacebo, 1.11, [95% confidence interval 0.90 to 1.36], p=0.32) (Table 1). Over 1 year, ticagrelor had no effect on troponin concentrations in patients with increased coronary 18F-fluoride uptake (ratio of geometric means, 0.86, 95% confidence interval 0.63 to 1.17, p=0.33).

Table 1 Adjusted Geometric Mean (GSE) Ratio of Geometric Means p-value Ticagrelor Placebo (95% CI) Cardiac troponin I, ng/L (18F-fluoride activity) 3.8 (1.1) 3.4 (1.1) 1.11 (0.90 to 1.36) 0.32 Cardiac Troponin I, ng/L (No 18F-fluoride activity) 2.4 (1.1) 2.3 (1.1) 1.02 (0.80 to 1.31) 0.87 Plasma high-sensitivity cardiac troponin I concentration (ng/L) at 30 days for the per-protocol population.Estimates are back transformed estimates from analysis of log transformed values at 30 days adjusting for age, sex and log transformed baseline troponin. Ratio of geometric means is Ticagrelor divided by Placebo. GSE, geometric standard error.

Conclusions

Dual antiplatelet therapy with ticagrelor does not reduce plasma troponin concentrations in patients with coronary 18F-fluoride uptake. This suggests that subclinical plaque thrombosis does not contribute to ongoing myocardial injury in this setting.

Clinical Trials Study ID: NCT02110303Study ID: NCT02110303

Acknowledgement/Funding

Wellcome Trust Senior Investigator Award WT103782AIA

The Relationship Between Psychological Flexibility, Value-Based Living and Emotional Well-Being in People Affected by Cancer

Background: Receiving a cancer diagnosis can have detrimental effects on an individual's psychological flexibility (ability to adapt constructively to reality), emotional well-being and ability to live aligned with personal values, for example, in relationships and work. Higher levels of psychological flexibility and emotional well-being are associated with better quality of life and lower psychological cancer-related distress. In turn, value-based living is positively associated with psychological flexibility and emotional well-being. There is, however, limited research specifically exploring the relationship between value-based living and emotional well-being within individuals affected by cancer. Maggie's Centres ( www.maggiescentres.org ) offer an innovative, multidisciplinary model of holistic supportive cancer care, widely regarded as an exemplar of best practice in cancer rehabilitation and supported self-management. In 2017 Maggie's received 249,247 visits across the network of Centres in the UK, Hong Kong and Tokyo. Principles of ACT (acceptance and commitment therapy) are incorporated within the program of individual support, psychoeducational courses and groups to help people maximize their quality of life. Aim: To explore the associations between psychological flexibility, value-based living and emotional well-being in individuals affected by cancer. Methods: Sixty-five people, affected by a cancer diagnosis personally or in a family member, were recruited from four UK Maggie's Centres. Participants completed standardized questionnaires measuring psychological flexibility, valued-based living and emotional well-being. Results: Moderate positive associations were found between emotional well-being and psychological flexibility (r=.4750), as well as emotional well-being and valued-living (r=.37983). Psychological flexibility was also positively associated with valued living (r=.443474). Multiple regression analysis revealed a significant model (F(5,54)=9.35, P < .001), accounting for 41.4% of the variance in emotional well-being (adjusted R2 = .414). Both psychological flexibility (b=.357, P = .002) and valued-living (b=.337, P = .004) were predictors of emotional well-being across all ages, gender and time since diagnosis. Conclusion: The study provides support for the positive associations between psychological flexibility, valued-living and emotional well-being and indicates that psychological flexibility and valued-living may be predictors of emotional well-being. This was a small observational study, so conclusions about causation or change over time cannot be made. Longitudinal intervention studies need to explore the potential impact valued-living and psychological flexibility may have on emotional well-being in those affected by cancer, and so contribute to understanding the potential importance of encouraging valued-living as a therapeutic tool within cancer care.

Genetic variation in hepatic glucose-6-phosphatase system genes in cases of sudden infant death syndrome

Genetic deficiencies of the hepatic glucose-6-phosphatase system, either of the enzyme (G6PC1) or of the glucose-6-phosphate transporter (G6PT1), result in fasting hypoglycaemia. Low hepatic G6PC1 activities were previously reported in a few term sudden infant death syndrome (SIDS) infants and assumed to be due to G6PC1 genetic deficiencies. In preterm infants, failures of postnatal activation of G6PC1 expression suggest disordered development as a novel cause of decreased G6PC1 activity in SIDS. G6PC1 and G6PT1 functional and mutational analysis was investigated in SIDS and non-SIDS infants. G6PC1 hepatic activity was abnormally low in 98 SIDS (preterm, n=13; term, n=85), and non-SIDS preterm infants (n=35) compared to term non-SIDS infants (n=29) and adults (n=9). Mean glycogen levels were elevated, except in term non-SIDS infants. A novel G6PT1 promoter polymorphism, 259C --> T was found; the - 259*T allele frequency was greater in term SIDS infants (n=140) than in term control infants (n=119) and preterm SIDS infants (n=30). Heterozygous and homozygous prevalence of 259C --> T was 38.6% and 7.1%, respectively, in term SIDS infants. In cell-based expression systems, the presence of - 259T in the promoter decreased basal luciferase activity by 3.2-fold compared to - 259C. Glucose-6-phosphatase latency in hepatic microsomes was elevated (indicating decreased G6PT1 function) in heterozygous and homozygous - 259T states. Delayed postnatal appearance of hepatic glucose-6-phosphatase in infants makes them vulnerable to hypoglycaemic episodes and this may occur in some SIDS infants. However, SIDS may be an association of more complex phenotypes in which several genes interact with multiple environmental factors. A UK-wide DNA Biobank of samples from all infant deaths, with an accompanying epidemiological database, should be established by pathologists to allow cumulative data to be collected from multiple genetic investigations on the same large cohort of samples, with the aim of selection of the best combination of genetic markers to predict unexpected infant death.

Thyroid hormone potentiates glucocorticoid-evoked airway Na+ transport without affecting alpha-ENaC transcription

Glucocorticoid and thyroid hormones (T3) are important for the development of the lungs' Na+ absorbing phenotype, which is essential for the integrated functioning of the respiratory tract. Electrometric studies of H441 airway epithelial cells confirmed that dexamethasone increases apical Na+ conductance (GNa) and demonstrated that T3 facilitates this control over GNa. Assays of transcriptional activity showed that dexamethasone caused concentration-dependent activation of the human alpha-ENaC promoter (EC50 approximately 5 nM) but, despite its clear effect on GNa, T2 had no effect upon the transcriptional response to dexamethasone. The facilitation of Na+ transport may thus reflect control over events downstream to transcription.

Polymorphisms in genes involved in glucose metabolism in cases of sudden infant death syndrome

BACKGROUND

Infants with intra-uterine growth retardation have an increased risk of Sudden Infant Death Syndrome (SIDS). Hypoglycaemia is also significantly correlated with retardation of intra-uterine growth. A number of mutations in key proteins involved in regulation of blood glucose (e.g. glucokinase) have been found to result in reduced birth weight. Heterozygous mutations in the coding region of the glucokinase gene have been shown to cause MODY (a form of early onset Type II diabetes mellitus). The aim was to screen a cohort of SIDS and control infants who were either growth retarded or appropriately grown for gestational age to determine if any mutations and/or polymorphisms were present in the glucokinase gene.

METHODS

PCR, denaturing high performance liquid chromatography on an automated Transgenomic WAVE DNA fragment analysis system and DNA sequencing.

RESULTS

Genomic DNA was isolated from 129 infants who were either growth retarded or appropriately grown for gestational age. We found several rare novel polymorphisms in the glucokinase gene in the infant samples. However, none of the samples contained any of the mutations in the glucokinase gene previously reported in cases of MODY.

CONCLUSIONS

We have found rare novel polymorphisms in the glucokinase gene in the infant samples. In contrast in these samples, we have not found any examples of the previously reported mutations in the coding region of the glucokinase gene found in MODY. This clearly shows that while MODY babies are often small, MODY is not a common cause of either intra-uterine growth retardation or of SIDS.

Protective immune responses to Theileria annulata of relevance to vaccine development

A series of projects on Theileria annulata funded by the European Union (STD1/STD2/STD3) have provided convincing evidence that macrophage and natural killer (NK) cell-dependent immune mechanisms may directly control the proliferation of different stages of T. annulata in cattle. The evidence for this conclusion and the implications for vaccine development are discussed in the following paper.

Partial trisomy 17q and a generalised bone dysplasia in a 12 week fetus

A fetus, which was spontaneously aborted at 12 weeks' gestation, was found to have a generalised bone dysplasia and an unbalanced karyotype with trisomy for 17q23.1----qter due to a maternal translocation: 46,XX,t(5;17)(p15.3;q23.1)mat.