In-silico functional analyses identify TMPRSS15-mediated intestinal absorption of lithium as a modulator of lithium response in bipolar disorder

BACKGROUND

The therapeutic response to lithium in patients with bipolar disorder is highly variable and has a polygenic basis. Genome-wide association studies investigating lithium response have identified several relevant loci, though the precise mechanisms driving these associations are poorly understood. We aimed to prioritise the most likely effector gene and determine the mechanisms underlying an intergenic lithium response locus on chromosome 21 identified by the International Consortium on Lithium Genetics (ConLi+Gen).

METHODS

We conducted in-silico functional analyses by integrating and synthesising information from several publicly available functional genetic datasets and databases including the Genotype-Tissue Expression (GTEx) project and HaploReg.

RESULTS

The findings from this study highlighted TMPRSS15 as the most likely effector gene at the ConLi+Gen lithium response locus. TMPRSS15 encodes enterokinase, a gastrointestinal enzyme responsible for converting trypsinogen into trypsin and thus aiding digestion. Convergent findings from gene-based lookups in human and mouse databases as well as co-expression network analyses of small intestinal RNA-seq data (GTEx) implicated TMPRSS15 in the regulation of intestinal nutrient absorption, including ions like sodium and potassium, which may extend to lithium.

LIMITATIONS

Although the findings from this study indicated that TMPRSS15 was the most likely effector gene at the ConLi+Gen lithium response locus, the evidence was circumstantial. Thus, the conclusions from this study need to be validated in appropriately designed wet-lab studies.

CONCLUSIONS

The findings from this study are consistent with a model whereby TMPRSS15 impacts the efficacy of lithium treatment in patients with bipolar disorder by modulating intestinal lithium absorption.

A Metabolome-Wide Mendelian Randomization Study Identifies Dysregulated Arachidonic Acid Synthesis as a Potential Causal Risk Factor for Bipolar Disorder

BACKGROUND

Bipolar disorder (BPD) is a debilitating mood disorder with an unclear etiology. A better understanding of the underlying pathophysiological mechanisms will help to identify novel targets for improved treatment options and prevention strategies. In this metabolome-wide Mendelian randomization study, we screened for metabolites that may have a causal role in BPD.

METHODS

We tested a total of 913 circulating metabolite exposures assessed in 14,296 Europeans using a mass spectrometry-based platform. For the BPD outcome, we used summary data from the largest and most recent genome-wide association study reported to date, including 41,917 BPD cases.

RESULTS

We identified 33 metabolites associated with BPD (padjusted < 5.48 × 10-5). Most of them were lipids, including arachidonic acid (β = -0.154, SE = 0.023, p = 3.30 × 10-11), a polyunsaturated omega-6 fatty acid, along with several complex lipids containing either an arachidonic or a linoleic fatty acid side chain. These associations did not extend to other closely related psychiatric disorders like schizophrenia or depression, although they may be involved in the regulation of lithium response. These lipid associations were driven by genetic variants within the FADS1/2/3 gene cluster, which is a robust BPD risk locus encoding a family of fatty acid desaturase enzymes that are responsible for catalyzing the conversion of linoleic acid into arachidonic acid. Statistical colocalization analyses indicated that 27 of the 33 metabolites shared the same genetic etiology with BPD at the FADS1/2/3 cluster, demonstrating that our findings are not confounded by linkage disequilibrium.

CONCLUSIONS

Overall, our findings support the notion that arachidonic acid and other polyunsaturated fatty acids may represent potential targets for BPD.

Phenome-wide association study of ovarian cancer identifies common comorbidities and reveals shared genetics with complex diseases and biomarkers

BACKGROUND

Ovarian cancer (OC) is commonly diagnosed among older women who have comorbidities. This hypothesis-free phenome-wide association study (PheWAS) aimed to identify comorbidities associated with OC, as well as traits that share a genetic architecture with OC.

METHODS

We used data from 181,203 white British female UK Biobank participants and analysed OC and OC subtype-specific genetic risk scores (OC-GRS) for an association with 889 diseases and 43 other traits. We conducted PheWAS and colocalization analyses for individual variants to identify evidence for shared genetic architecture.

RESULTS

The OC-GRS was associated with 10 diseases, and the clear cell OC-GRS was associated with five diseases at the FDR threshold (p = 5.6 × 10-4 ). Mendelian randomizaiton analysis (MR) provided robust evidence for the association of OC with higher risk of "secondary malignant neoplasm of digestive systems" (OR 1.64, 95% CI 1.33, 2.02), "ascites" (1.48, 95% CI 1.17, 1.86), "chronic airway obstruction" (1.17, 95% CI 1.07, 1.29), and "abnormal findings on examination of the lung" (1.51, 95% CI 1.22, 1.87). Analyses of lung spirometry measures provided further support for compromised respiratory function. PheWAS on individual OC variants identified five genetic variants associated with other diseases, and seven variants associated with biomarkers (all, p ≤ 4.5 × 10-8 ). Colocalization analysis identified rs4449583 (from TERT locus) as the shared causal variant for OC and seborrheic keratosis.

CONCLUSIONS

OC is associated with digestive and respiratory comorbidities. Several variants affecting OC risk were associated with other diseases and biomarkers, with this study identifying a novel genetic locus shared between OC and skin conditions.

Genetics of circulating inflammatory proteins identifies drivers of immune-mediated disease risk and therapeutic targets

Circulating proteins have important functions in inflammation and a broad range of diseases. To identify genetic influences on inflammation-related proteins, we conducted a genome-wide protein quantitative trait locus (pQTL) study of 91 plasma proteins measured using the Olink Target platform in 14,824 participants. We identified 180 pQTLs (59 cis, 121 trans). Integration of pQTL data with eQTL and disease genome-wide association studies provided insight into pathogenesis, implicating lymphotoxin-α in multiple sclerosis. Using Mendelian randomization (MR) to assess causality in disease etiology, we identified both shared and distinct effects of specific proteins across immune-mediated diseases, including directionally discordant effects of CD40 on risk of rheumatoid arthritis versus multiple sclerosis and inflammatory bowel disease. MR implicated CXCL5 in the etiology of ulcerative colitis (UC) and we show elevated gut CXCL5 transcript expression in patients with UC. These results identify targets of existing drugs and provide a powerful resource to facilitate future drug target prioritization.

Instruments to assess appropriateness of hip and knee arthroplasty: a systematic review

OBJECTIVE

To assess criteria and psychometric properties of instruments for assessing appropriateness of elective joint arthroplasty (JA) for adults with primary hip and knee osteoarthritis (OA).

METHODS

A systematic review guided by Cochrane methods and PRISMA guidelines. Studies were searched in five databases. Eligible articles include all study designs developing, testing, and/or using an instrument to assess JA appropriateness. Two independent reviewers screened and extracted data. Instruments were compared with Hawker et al. JA consensus criteria. Psychometric properties of instruments were described and appraised guided by Fitzpatrick's and COSMIN approaches.

RESULTS

Of 55 instruments included, none met all Hawker et al. JA consensus criteria. Criteria the most met were pain (n = 50), function (n = 49), quality of life (n = 33), and radiography (n = 24). Criteria the least met were clinical evidence of OA (n = 18), expectations (n = 15), readiness for surgery (n = 11), conservative treatments (n = 8), and patient/surgeon agree benefits outweigh risks (n = 0). Instrument by Arden et al. met the most criteria (6 of 9). The most tested psychometric properties were appropriateness (n = 55), face/content validity (n = 55), predictive validity (n = 29), construct validity and feasibility (n = 24). The least tested psychometric properties were intra-rater reliability (n = 3), internal consistency (n = 5), and inter-rater reliability (n = 13). Instruments by Gutacker et al. and Osborne et al. met the most psychometric properties (4 of 10).

CONCLUSION

Most instruments included traditional criteria for assessing JA appropriateness but did not include a trial of conservative treatments or shared decision-making elements. There was limited evidence on psychometric properties.

Multi-omics data integration methods and their applications in psychiatric disorders

To study mental illness and health, in the past researchers have often broken down their complexity into individual subsystems (e.g., genomics, transcriptomics, proteomics, clinical data) and explored the components independently. Technological advancements and decreasing costs of high throughput sequencing has led to an unprecedented increase in data generation. Furthermore, over the years it has become increasingly clear that these subsystems do not act in isolation but instead interact with each other to drive mental illness and health. Consequently, individual subsystems are now analysed jointly to promote a holistic understanding of the underlying biological complexity of health and disease. Complementing the increasing data availability, current research is geared towards developing novel methods that can efficiently combine the information rich multi-omics data to discover biologically meaningful biomarkers for diagnosis, treatment, and prognosis. However, clinical translation of the research is still challenging. In this review, we summarise conventional and state-of-the-art statistical and machine learning approaches for discovery of biomarker, diagnosis, as well as outcome and treatment response prediction through integrating multi-omics and clinical data. In addition, we describe the role of biological model systems and in silico multi-omics model designs in clinical translation of psychiatric research from bench to bedside. Finally, we discuss the current challenges and explore the application of multi-omics integration in future psychiatric research. The review provides a structured overview and latest updates in the field of multi-omics in psychiatry.

Elucidating mechanisms of genetic cross-disease associations at the PROCR vascular disease locus

Many individual genetic risk loci have been associated with multiple common human diseases. However, the molecular basis of this pleiotropy often remains unclear. We present an integrative approach to reveal the molecular mechanism underlying the PROCR locus, associated with lower coronary artery disease (CAD) risk but higher venous thromboembolism (VTE) risk. We identify PROCR-p.Ser219Gly as the likely causal variant at the locus and protein C as a causal factor. Using genetic analyses, human recall-by-genotype and in vitro experimentation, we demonstrate that PROCR-219Gly increases plasma levels of (activated) protein C through endothelial protein C receptor (EPCR) ectodomain shedding in endothelial cells, attenuating leukocyte-endothelial cell adhesion and vascular inflammation. We also associate PROCR-219Gly with an increased pro-thrombotic state via coagulation factor VII, a ligand of EPCR. Our study, which links PROCR-219Gly to CAD through anti-inflammatory mechanisms and to VTE through pro-thrombotic mechanisms, provides a framework to reveal the mechanisms underlying similar cross-phenotype associations.

Transcriptional biomarkers of response to pharmacological treatments in severe mental disorders: A systematic review

Variation in the expression level and activity of genes involved in drug disposition and action in tissues of pharmacological importance have been increasingly investigated in patients treated with psychotropic drugs. Findings are promising, but reliable predictive biomarkers of response have yet to be identified. Here we conducted a PRISMA-compliant systematic search of PubMed, Scopus and PsycInfo up to 12 September 2020 for studies investigating RNA expression levels in cells or biofluids from patients with major depressive disorder, schizophrenia or bipolar disorder characterized for response to psychotropic drugs (antidepressants, antipsychotics or mood stabilizers) or adverse effects. Among 5497 retrieved studies, 123 (63 on antidepressants, 33 on antipsychotics and 27 on mood stabilizers) met inclusion criteria. Studies were either focused on mRNAs (n = 96), microRNAs (n = 19) or long non-coding RNAs (n = 1), with only a minority investigating both mRNAs and microRNAs levels (n = 7). The most replicated results include genes playing a role in inflammation (antidepressants), neurotransmission (antidepressants and antipsychotics) or mitochondrial function (mood stabilizers). Compared to those investigating response to antidepressants, studies focused on antipsychotics or mood stabilizers more often showed lower sample size and lacked replication. Strengths and limitations of available studies are presented and discussed in light of the specific designs, methodology and clinical characterization of included patients for transcriptomic compared to DNA-based studies. Finally, future directions of transcriptomics of psychopharmacological interventions in psychiatric disorders are discussed.

Recommendations for pharmacotranscriptomic profiling of drug response in CNS disorders

Pharmacotranscriptomics is a still very new field of research that has just begun to flourish and promises to enable target discovery, inform biomarker and evaluate drug efficacy beyond pharmacogenomics. The aim of this review is to provide a critical overview of the biological foundations of transcriptomics, methodological approaches to transcriptomic studies, and their advantages and limitations. We present the different RNA species (rRNAs, tRNAs, mtRNAs, snRNAs, scRNAs, mRNAs, ncRNAs, LINE and SINE transcripts, circular RNAs, piRNAs, miRNAs, snoRNAs) and their potential for pharmacotranscriptomic studies as markers to predict treatment response in neurological and psychiatric disorders. We also review the accessible sources of RNA in patients peripheral blood cells (including platelets), plasma, microvesicles, exosomes, apoptotic bodies, and how those affect the integrity and relative abundances of RNAs and reflect the situation in the Central Nervous System (CNS). Finally, we discuss the suitability and indications of different techniques, such as microarrays and RNA-sequencing (RNA-Seq) techniques to understand gene expression differences or to reveal variation in expression levels of coding and non-coding genes. We conclude with some recommendations for future directions, e.g., gaps of knowledge and particular RNAs/tissues that have been overlooked.

Global Burden of Animal Diseases: a novel approach to understanding and managing disease in livestock and aquaculture

Investments in animal health and Veterinary Services can have a measurable impact on the health of people and the environment. These investments require a baseline metric that describes the burden of animal health and welfare in order to justify and prioritise resource allocation and from which to measure the impact of interventions. This paper is part of a process of scientific enquiry in which problems are identified and solutions sought in an inclusive way. It poses the broad question: what should a system to measure the animal disease burden on society look like and what value would it add? Moreover, it aims to do this in such a way as to be accessible by a wide audience, who are encouraged to engage in this debate. Given that farmed animals, including those raised by poor smallholders, are an economic entity, this system should be based on economic principles. These poor farmers are negatively impacted by disparities in animal health technology, which can be addressed through a mixture of supply-led and demand-driven interventions, reinforcing the relevance of targeted financial support from government and non-governmental organisations. The Global Burden of Animal Diseases (GBADs) Programme will glean existing data to measure animal health losses within carefully characterised production systems. Consistent and transparent attribution of animal health losses will enable meaningful comparisons of the animal disease burden to be made between diseases, production systems and countries, and will show how it is apportioned by people's socio-economic status and gender. The GBADs Programme will produce a cloud-based knowledge engine and data portal, through which users will access burden metrics and associated visualisations, support for decisionmaking in the form of future animal health scenarios, and the outputs of wider economic modelling. The vision of GBADs, strengthening the food system for the benefit of society and the environment, is an example of One Health thinking in action.

Genome-wide analysis of blood lipid metabolites in over 5000 South Asians reveals biological insights at cardiometabolic disease loci

BACKGROUND

Genetic, lifestyle, and environmental factors can lead to perturbations in circulating lipid levels and increase the risk of cardiovascular and metabolic diseases. However, how changes in individual lipid species contribute to disease risk is often unclear. Moreover, little is known about the role of lipids on cardiovascular disease in Pakistan, a population historically underrepresented in cardiovascular studies.

METHODS

We characterised the genetic architecture of the human blood lipidome in 5662 hospital controls from the Pakistan Risk of Myocardial Infarction Study (PROMIS) and 13,814 healthy British blood donors from the INTERVAL study. We applied a candidate causal gene prioritisation tool to link the genetic variants associated with each lipid to the most likely causal genes, and Gaussian Graphical Modelling network analysis to identify and illustrate relationships between lipids and genetic loci.

RESULTS

We identified 253 genetic associations with 181 lipids measured using direct infusion high-resolution mass spectrometry in PROMIS, and 502 genetic associations with 244 lipids in INTERVAL. Our analyses revealed new biological insights at genetic loci associated with cardiometabolic diseases, including novel lipid associations at the LPL, MBOAT7, LIPC, APOE-C1-C2-C4, SGPP1, and SPTLC3 loci.

CONCLUSIONS

Our findings, generated using a distinctive lipidomics platform in an understudied South Asian population, strengthen and expand the knowledge base of the genetic determinants of lipids and their association with cardiometabolic disease-related loci.

Genome-wide association study of circulating interleukin 6 levels identifies novel loci

Interleukin 6 (IL-6) is a multifunctional cytokine with both pro- and anti-inflammatory properties with a heritability estimate of up to 61%. The circulating levels of IL-6 in blood have been associated with an increased risk of complex disease pathogenesis. We conducted a two-staged, discovery and replication meta genome-wide association study (GWAS) of circulating serum IL-6 levels comprising up to 67 428 (ndiscovery = 52 654 and nreplication = 14 774) individuals of European ancestry. The inverse variance fixed effects based discovery meta-analysis, followed by replication led to the identification of two independent loci, IL1F10/IL1RN rs6734238 on chromosome (Chr) 2q14, (Pcombined = 1.8 × 10-11), HLA-DRB1/DRB5 rs660895 on Chr6p21 (Pcombined = 1.5 × 10-10) in the combined meta-analyses of all samples. We also replicated the IL6R rs4537545 locus on Chr1q21 (Pcombined = 1.2 × 10-122). Our study identifies novel loci for circulating IL-6 levels uncovering new immunological and inflammatory pathways that may influence IL-6 pathobiology.

Reporting health research translation and impact in the curriculum vitae: a survey

Background

Increasingly, health researchers must demonstrate the impact and real-life applications of their research. We investigated how health researchers with expertise in knowledge translation report research translation activities and impact on their curriculum vitae (CV).

Methods

We conducted a cross-sectional survey of health researchers with expertise in knowledge translation as we anticipated best practices in CV reporting from this specialized group. Our survey asked participants about their reporting of research translation and impact activities on their CVs, intention to report, and barriers and facilitators to reporting such activities on their CVs. We calculated univariate descriptive statistics for all quantitative data. Linear regression models determined predictors of researchers’ intention to report research translation and impact activities on their CVs. We analyzed open-ended qualitative responses using content analysis.

Results

One hundred and fifty-three health researchers responded to the survey (response rate = 29%). Most respondents were Canadian, were female, and had a doctoral degree. Eighty-two percent indicated they reported at least one research translation and/or impact indicator on their CVs. Of those, health researchers commonly reported the following: advisory/regulatory committee membership related to research program (83%), research translation award(s) (61%), and academic performance assessments (59%). Researchers least commonly indicated the following: citation metric scores (31%), summaries of impact (21%), and requests to use research materials and/or products (19%). Fewer than half of the health researchers intended to report knowledge translation (43%) and impact (33%) on their CVs. Strong beliefs about capabilities and consequences of reporting research translation and/or impact were significant predictors of intention. Main barriers were as follows: CV templates do not include research translation and impact activities, participants perceived employers do not value research translation and impact activities, and lack of metrics to evaluate research translation and impact. Ninety-six percent were unaware of a CV template formatted to include research translation and/or impact reporting.

Conclusions

Knowledge translation and impact indicators on the CV are inconsistently reported by our sample of health researchers. Modifiable barriers should be addressed to support more consistent reporting of such activities, including providing a CV template that includes research translation and impact as well as clear metrics to quantify them.

Long-term effect of patient decision aids on use of joint replacement and health care costs

OBJECTIVE

Shared decision-making supported by patient decisions aids may improve care and reduce healthcare costs for persons considering total joint replacement. Observational studies and randomized controlled trials (RCTs) have evaluated the short-term impact of decision aids on uptake of surgery and costs, however the long-term effects are unclear. This analysis aimed to evaluate the effect of patient decision aids on 1) use of joint replacement up to 7-years of follow-up, and 2) osteoarthritis-related health system costs.

METHODS

324 participants in a Canadian RCT with 2-years follow-up who were randomized to either a decision aid (n = 161) or usual care (n = 163) had their trial and health administrative data linked. The proportion undergoing surgery up to 7-years were compared using cumulative incidence plots and competing risk regression. Mean per-patient costs were compared using two sample t-tests.

RESULTS

At 2-years, 119 of 161 (73.9%) patients in the decision aid arm and 129 of 163 (79.1%) patients in the usual care arm had surgery. Between two and 7-years, 17 additional patients in both the decision aid (of 42, 40.4%) and usual care (of 34, 50.0%) arms underwent surgery. At 7-years, patients exposed to decision aids had a similar likelihood of undergoing surgery (HR = 0.92, 95% CI:0.73 to 1.17, p = 0.49) and mean per-patient costs ($21,965 vs $23,681, incremental cost: -$1,717, 95% CI:-$5,631 to $2,198) compared to those in usual care.

CONCLUSIONS

This is the first study to assess the long-term impact of decision aids on use of joint replacement and healthcare costs. These results are not conclusive but can inform future trial design.

CLINICAL TRIAL REGISTRATION

The full trial protocol is available at ClinicalTrials.Gov (NCT00911638).

Downregulated transferrin receptor in the blood predicts recurrent MDD in the elderly cohort: A fuzzy forests approach

BACKGROUND

At present, no predictive markers for Major Depressive Disorder (MDD) exist. The search for such markers has been challenging due to clinical and molecular heterogeneity of MDD, the lack of statistical power in studies and suboptimal statistical tools applied to multidimensional data. Machine learning is a powerful approach to mitigate some of these limitations.

METHODS

We aimed to identify the predictive markers of recurrent MDD in the elderly using peripheral whole blood from the Sydney Memory and Aging Study (SMAS) (N = 521, aged over 65) and adopting machine learning methodology on transcriptome data. Fuzzy Forests is a Random Forests-based classification algorithm that takes advantage of the co-expression network structure between genes; it allows to alleviate the problem of p >> n via reducing the dimensionality of transcriptomic feature space.

RESULTS

By adopting Fuzzy Forests on transcriptome data, we found that the downregulated TFRC (transferrin receptor) can predict recurrent MDD with an accuracy of 63%.

LIMITATIONS

Although we corrected our data for several important confounders, we were not able to account for the comorbidities and medication taken, which may be numerous in the elderly and might have affected the levels of gene transcription.

CONCLUSIONS

We found that downregulated TFRC is predictive of recurrent MDD, which is consistent with the previous literature, indicating the role of the innate immune system in depression. This study is the first to successfully apply Fuzzy Forests methodology on psychiatric condition, opening, therefore, a methodological avenue that can lead to clinically useful predictive markers of complex traits.

Exploring reasons for overuse of contralateral prophylactic mastectomy in Canada

Background

Contralateral prophylactic mastectomy (cpm) in women with known unilateral breast cancer (bca) has been increasing despite the lack of supportive evidence. The purpose of the present study was to identify the determinants of cpm in women with unilateral bca.

Methods

This qualitative descriptive study used semi-structured interviews informed by the Theoretical Domains Framework. We interviewed 74 key informants (surgical oncologists, plastic surgeons, medical oncologists, radiation oncologists, nurses, women with bca) across Canada. Interviews were analyzed using thematic analysis and an analysis for shared and discipline-specific beliefs.

Results

In total, 58 factors influencing the use of cpm were identified: 26 factors shared by various health care professional groups, 15 discipline-specific factors (identified by a single health care professional group), and 17 factors shared by women with unilateral bca. Health care professionals identified more factors discouraging the use of cpm (n = 26) than encouraging its use (n = 15); women with bca identified more factors encouraging use of cpm (n = 12) than discouraging its use (n = 5). The factor most commonly identified by health care professionals that encouraged cpm was lack of awareness of existing evidence or guidelines for the appropriate use of cpm (n = 44, 75%). For women with bca, the factor most likely influencing their decision for cpm was wanting a better esthetic outcome (n = 14, 93%).

Conclusions

Multiple factors discouraging and encouraging the use of cpm in unilateral bca were identified. Those factors identify potential individual, team, organization, and system targets for behaviour change interventions to reduce cpm.

Research priorities for the pan-Canadian Oncology Symptom Triage and Remote Support practice guides: a modified nominal group consensus

Introduction

The pan-Canadian Oncology Symptom Triage and Remote Support (costars) team is studying how to improve the quality and consistency of cancer symptom management.

Methods

A 1-day invitational meeting was held 24 October 2017 in Ottawa, Ontario, to review the current evidence from costars projects and to establish research priorities for a future largescale implementation study. The meeting included 36 participants who were clinicians from adult oncology, pediatric oncology, and homecare; policymakers from national, provincial, and regional organizations; researchers; and a patient. Half the day involved summarizing evidence from four costars studies and experiences with implementing the costars symptom practice guides. The second half of the day used a modified nominal group technique to generate research questions within small groups, presentation of research questions to all participants, and two rounds of voting to reach consensus on research priorities.

Results

Participants proposed 4 research categories:■ User-centred augmentation to enhance usability (for example, designing a mobile costars solution)■ Outcome measurement (for example, determining key competencies for clinicians)■ Regular renewal of costars to keep pace with evolving evidence (for example, updates for novel therapies)■ Integration into clinical practice (for example, meaningful engagement of patients and caregivers in study design).

Conclusions

Across categories, the top 3 priorities were effect on health services use, competency development, and a mobile costars solution. Future research will address identified priorities, reflecting the needs and perspectives of diverse stakeholders. Stakeholder collaboration will continue to guide our approach to operationalizing this priority research agenda.

An Unbiased Lipid Phenotyping Approach To Study the Genetic Determinants of Lipids and Their Association with Coronary Heart Disease Risk Factors

Direct infusion high-resolution mass spectrometry (DIHRMS) is a novel, high-throughput approach to rapidly and accurately profile hundreds of lipids in human serum without prior chromatography, facilitating in-depth lipid phenotyping for large epidemiological studies to reveal the detailed associations of individual lipids with coronary heart disease (CHD) risk factors. Intact lipid profiling by DIHRMS was performed on 5662 serum samples from healthy participants in the Pakistan Risk of Myocardial Infarction Study (PROMIS). We developed a novel semi-targeted peak-picking algorithm to detect mass-to-charge ratios in positive and negative ionization modes. We analyzed lipid partial correlations, assessed the association of lipid principal components with established CHD risk factors and genetic variants, and examined differences between lipids for a common genetic polymorphism. The DIHRMS method provided information on 360 lipids (including fatty acyls, glycerolipids, glycerophospholipids, sphingolipids, and sterol lipids), with a median coefficient of variation of 11.6% (range: 5.4-51.9). The lipids were highly correlated and exhibited a range of associations with clinical chemistry biomarkers and lifestyle factors. This platform can provide many novel insights into the effects of physiology and lifestyle on lipid metabolism, genetic determinants of lipids, and the relationship between individual lipids and CHD risk factors.

Patient decision aid for contralateral prophylactic mastectomy for use in the consultation: a feasibility study

Background

Rates of contralateral prophylactic mastectomy (cpm) continue to rise internationally despite evidence-based guidance strongly discouraging its use in most women with unilateral breast cancer. The purpose of the present study was to develop and assess the feasibility of a knowledge translation tool [a patient decision aid (da)] designed to enhance evidence-informed shared decision-making about cpm.

Methods

A consultation da was developed using the Ottawa Patient Decision Aid Development eTraining in consultation with clinicians and knowledge translation experts. The final da was then assessed for feasibility with health care professionals and patients across Canada. The assessment involved a survey completed online (health care professionals) or by telephone (patients). Survey data were analyzed using descriptive statistics for closed-ended questions and qualitative content analysis for open-ended questions.

Results

The 51 participants who completed the survey included 39 health care professionals and 12 patients. The da was acceptable; 88% of participants viewed it as having the right amount of information or slightly more or less information than they would like. Almost all participants (98%) felt that the da would prepare patients to make better decisions. The aid was perceived to be usable, with 73% of participants stating that they would be willing to use or share the da.

Conclusions

The cpm patient da developed for the present study was viewed by health care professionals and patients across Canada to be acceptable and usable during the clinical consultation. It holds promise as a knowledge translation tool to be used by clinicians in consultation with women who have unilateral breast cancer to enhance evidence-informed and shared decision-making with respect to undergoing cpm.

Shared medical appointments for patients with a nondiabetic physical chronic illness: A systematic review

OBJECTIVES

Shared medical appointments are group appointments, with an optional individual consultation, for patients diagnosed with chronic illnesses. Shared medical appointments improve diabetes management, but little is known about their use for other illnesses. The objective was to determine the effect that shared medical appointments have on patients with a physical chronic illness, healthcare providers, and the healthcare system.

METHODS

A systematic review was conducted searching databases from January 1970 to September 2016. Eligible trials evaluated shared medical appointments for patients with a homogeneous chronic illness, excluding diabetes and mental illness. Screening, data extraction, and risk of bias were conducted independently by two authors. Analysis was descriptive.

RESULTS

Of 2364 citations, nine randomized trials were included. Shared medical appointments were evaluated for cardiovascular illnesses (four studies), breast cancer, chronic kidney disease, Parkinson's disease, stress urinary incontinence, and carpal tunnel syndrome. Compared to usual care, no negative effects on patient quality of life, knowledge and satisfaction were reported. One study reported no difference in healthcare provider satisfaction. Another study showed fewer hospital admissions for patients who attended shared medical appointments.

DISCUSSION

Few rigorous studies evaluated the use of shared medical appointments for chronic illnesses. Overall, there appears to be no patient harms. Further studies should include more objective outcomes and larger sample sizes.

Factors influencing the use by radiation therapists of cancer symptom guides: a mixed-methods study

Background Radiation therapists play an important role in helping patients to safely manage and triage potentially life-threatening symptoms. The purpose of the present study was to assess factors influencing the use by radiation therapists of evidence-informed symptom practice guides for patients experiencing cancer treatment–related symptoms.Methods In a mixed-methods descriptive study guided by the Knowledge-to-Action framework, interviews and a barriers survey were conducted. Two independent reviewers conducted a content analysis of interview transcripts. Barriers survey data were analyzed using frequency distributions and univariate descriptive statistics. Open-ended data from the surveys underwent content analysis and were triangulated with interview findings.Results Of 90 radiation therapists approached, 58 completed the survey (64%), and 14 were interviewed. Of the 98% who reported providing symptom management to patients undergoing radiation treatment, 53% used evidence-informed practice guidelines. Radiation therapists had moderate moral norms (4.6 of 7) and beliefs about the consequences of using costars (pan Canadian Oncology Symptom Triage and Remote Support) practice guides (4.8), but neutral intention (3.4) and beliefs about their own capabilities (3.9). Environmental barriers included lack of time (2.0), lack of access (2.5), and neutral organizational support (3.0). Radiation therapists identified a need for training (5.5). Common unique barriers to practice guide use were lack of time during radiation treatments, unclear fit with scope of practice, disparate focus on site-specific symptoms, and lack of medication knowledge.Conclusions The symptom practice guides were perceived by the radiation therapists to benefit patients, enhance their own knowledge of symptom management, and promote consistent practice. Additional work is required to identify the scope of practice of radiation therapists within the interprofessional team.

Factors influencing the use by radiation therapists of cancer symptom guides: a mixed-methods study

Background

Radiation therapists play an important role in helping patients to safely manage and triage potentially life-threatening symptoms. The purpose of the present study was to assess factors influencing the use by radiation therapists of evidence-informed symptom practice guides for patients experiencing cancer treatment-related symptoms.

Methods

In a mixed-methods descriptive study guided by the Knowledge-to-Action framework, interviews and a barriers survey were conducted. Two independent reviewers conducted a content analysis of interview transcripts. Barriers survey data were analyzed using frequency distributions and univariate descriptive statistics. Open-ended data from the surveys underwent content analysis and were triangulated with interview findings.

Results

Of 90 radiation therapists approached, 58 completed the survey (64%), and 14 were interviewed. Of the 98% who reported providing symptom management to patients undergoing radiation treatment, 53% used evidence-informed practice guidelines. Radiation therapists had moderate moral norms (4.6 of 7) and beliefs about the consequences of using costars (pan-Canadian Oncology Symptom Triage and Remote Support) practice guides (4.8), but neutral intention (3.4) and beliefs about their own capabilities (3.9). Environmental barriers included lack of time (2.0), lack of access (2.5), and neutral organizational support (3.0). Radiation therapists identified a need for training (5.5). Common unique barriers to practice guide use were lack of time during radiation treatments, unclear fit with scope of practice, disparate focus on site-specific symptoms, and lack of medication knowledge.

Conclusions

The symptom practice guides were perceived by the radiation therapists to benefit patients, enhance their own knowledge of symptom management, and promote consistent practice. Additional work is required to identify the scope of practice of radiation therapists within the interprofessional team.

ProGeM: a framework for the prioritization of candidate causal genes at molecular quantitative trait loci

Quantitative trait locus (QTL) mapping of molecular phenotypes such as metabolites, lipids and proteins through genome-wide association studies represents a powerful means of highlighting molecular mechanisms relevant to human diseases. However, a major challenge of this approach is to identify the causal gene(s) at the observed QTLs. Here, we present a framework for the 'Prioritization of candidate causal Genes at Molecular QTLs' (ProGeM), which incorporates biological domain-specific annotation data alongside genome annotation data from multiple repositories. We assessed the performance of ProGeM using a reference set of 227 previously reported and extensively curated metabolite QTLs. For 98% of these loci, the expert-curated gene was one of the candidate causal genes prioritized by ProGeM. Benchmarking analyses revealed that 69% of the causal candidates were nearest to the sentinel variant at the investigated molecular QTLs, indicating that genomic proximity is the most reliable indicator of 'true positive' causal genes. In contrast, cis-gene expression QTL data led to three false positive candidate causal gene assignments for every one true positive assignment. We provide evidence that these conclusions also apply to other molecular phenotypes, suggesting that ProGeM is a powerful and versatile tool for annotating molecular QTLs. ProGeM is freely available via GitHub.

Co-expression network analysis of peripheral blood transcriptome identifies dysregulated protein processing in endoplasmic reticulum and immune response in recurrent MDD in older adults

The molecular factors involved in the pathophysiology of major depressive disorder (MDD) remain poorly understood. One approach to examine the molecular basis of MDD is co-expression network analysis, which facilitates the examination of complex interactions between expression levels of individual genes and how they influence biological pathways affected in MDD. Here, we applied an unsupervised gene-network based approach to a prospective experimental design using microarray genome-wide gene expression from the peripheral whole blood of older adults. We utilised the Sydney Memory and Ageing Study (sMAS, N = 521) and the Older Australian Twins Study (OATS, N = 186) as discovery and replication cohorts, respectively. We constructed networks using Weighted Gene Co-expression Network Analysis (WGCNA), and correlated identified modules with four subtypes of depression: single episode, current, recurrent, and lifetime MDD. Four modules of highly co-expressed genes were associated with recurrent MDD (N = 27) in our discovery cohort (FDR<0.2), with no significant findings for a single episode, current or lifetime MDD. Functional characterisation of these modules revealed a complex interplay between dysregulated protein processing in the endoplasmic reticulum (ER), and innate and adaptive immune response signalling, with possible involvement of pathogen-related pathways. We were underpowered to replicate findings at the network level in an independent cohort (OATS), however; we found a significant overlap for 9 individual genes with similar co-expression and dysregulation patterns associated with recurrent MDD in both cohorts. Overall, our findings support other reports on dysregulated immune response and protein processing in the ER in MDD and provide novel insights into the pathophysiology of depression.

The effect of surgery report cards on improving radical prostatectomy quality: the SuRep study protocol

Background

The goal of radical prostatectomy is to achieve the optimal balance between complete cancer removal and preserving a patient’s urinary and sexual function. Performing a wider excision of peri-prostatic tissue helps achieve negative surgical margins, but can compromise urinary and sexual function. Alternatively, sparing peri-prostatic tissue to maintain functional outcomes may result in an increased risk of cancer recurrence. The objective of this study is to determine the effect of providing surgeons with detailed information about their patient outcomes through a surgical report card.

Methods

We propose a prospective cohort quasi-experimental study. The intervention is the provision of feedback to prostate cancer surgeons via surgical report cards. These report cards will be distributed every 3 months by email and will present surgeons with detailed information, including urinary function, erectile function, and surgical margin outcomes of their patients compared to patients treated by other de-identified surgeons in the study. For the first 12 months of the study, pre-operative, 6-month, and 12-month patient data will be collected but there will be no report cards distributed to surgeons. This will form the pre-feedback cohort. After the pre-feedback cohort has completed accrual, surgeons will receive quarterly report cards. Patients treated after the provision of report cards will comprise the post-feedback cohort. The primary comparison will be post-operative function of the pre-feedback cohort vs. post-feedback cohort. The secondary comparison will be the proportion of patients with positive surgical margins in the two cohorts. Outcomes will be stratified or case-mix adjusted, as appropriate. Assuming a baseline potency of 20% and a baseline continence of 70%, 292 patients will be required for 80% power at an alpha of 5% to detect a 10% improvement in functional outcomes. Assuming 30% of patients may be lost to follow-up, a minimum sample size of 210 patients is required in the pre-feedback cohort and 210 patients in the post-feedback cohort.

Discussion

The findings from this study will have an immediate impact on surgeon self-evaluation and we hypothesize surgical report cards will result in improved overall outcomes of men treated with radical prostatectomy.

Electronic supplementary material

The online version of this article (10.1186/s12894-018-0403-y) contains supplementary material, which is available to authorized users.

A gene co-expression module implicating the mitochondrial electron transport chain is associated with long-term response to lithium treatment in bipolar affective disorder

Lithium is the first-line treatment for bipolar affective disorder (BPAD) but two-thirds of patients respond only partially or not at all. The reasons for this high variability in lithium response are not well understood. Transcriptome-wide profiling, which tests the interface between genes and the environment, represents a viable means of exploring the molecular mechanisms underlying lithium response variability. Thus, in the present study we performed co-expression network analyses of whole-blood-derived RNA-seq data from n = 50 lithium-treated BPAD patients. Lithium response was assessed using the well-validated ALDA scale, which we used to define both a continuous and a dichotomous measure. We identified a nominally significant correlation between a co-expression module comprising 46 genes and lithium response represented as a continuous (i.e., scale ranging 0-10) phenotype (cor = -0.299, p = 0.035). Forty-three of these 46 genes had reduced mRNA expression levels in better lithium responders relative to poorer responders, and the central regulators of this module were all mitochondrially-encoded (MT-ND1, MT-ATP6, MT-CYB). Accordingly, enrichment analyses indicated that genes involved in mitochondrial functioning were heavily over-represented in this module, specifically highlighting the electron transport chain (ETC) and oxidative phosphorylation (OXPHOS) as affected processes. Disrupted ETC and OXPHOS activity have previously been implicated in the pathophysiology of BPAD. Our data adds to previous evidence suggesting that a normalisation of these processes could be central to lithium's mode of action, and could underlie a favourable therapeutic response.

From lipid locus to drug target through human genomics

In the last decade, over 175 genetic loci have robustly been associated to levels of major circulating blood lipids. Most loci are specific to one or two lipids, whereas some (SUGP1, ZPR1, TRIB1, HERPUD1, and FADS1) are associated to all. While exposing the polygenic architecture of circulating lipids and the underpinnings of dyslipidaemia, these genome-wide association studies (GWAS) have provided further evidence of the critical role that lipids play in coronary heart disease (CHD) risk, as indicated by the 2.7-fold enrichment for macrophage gene expression in atherosclerotic plaques and the association of 25 loci (such as PCSK9, APOB, ABCG5-G8, KCNK5, LPL, HMGCR, NPC1L1, CETP, TRIB1, ABO, PMAIP1-MC4R, and LDLR) with CHD. These GWAS also confirmed known and commonly used therapeutic targets, including HMGCR (statins), PCSK9 (antibodies), and NPC1L1 (ezetimibe). As we head into the post-GWAS era, we offer suggestions for how to move forward beyond genetic risk loci, towards refining the biology behind the associations and identifying causal genes and therapeutic targets. Deep phenotyping through lipidomics and metabolomics will refine and increase the resolution to find causal and druggable targets, and studies aimed at demonstrating gene transcriptional and regulatory effects of lipid associated loci will further aid in identifying these targets. Thus, we argue the need for deeply phenotyped, large genetic association studies to reduce costs and failures and increase the efficiency of the drug discovery pipeline. We conjecture that in the next decade a paradigm shift will tip the balance towards a data-driven approach to therapeutic target development and the application of precision medicine where human genomics takes centre stage.

Genomic atlas of the human plasma proteome

Although plasma proteins have important roles in biological processes and are the direct targets of many drugs, the genetic factors that control inter-individual variation in plasma protein levels are not well understood. Here we characterize the genetic architecture of the human plasma proteome in healthy blood donors from the INTERVAL study. We identify 1,927 genetic associations with 1,478 proteins, a fourfold increase on existing knowledge, including trans associations for 1,104 proteins. To understand the consequences of perturbations in plasma protein levels, we apply an integrated approach that links genetic variation with biological pathway, disease, and drug databases. We show that protein quantitative trait loci overlap with gene expression quantitative trait loci, as well as with disease-associated loci, and find evidence that protein biomarkers have causal roles in disease using Mendelian randomization analysis. By linking genetic factors to diseases via specific proteins, our analyses highlight potential therapeutic targets, opportunities for matching existing drugs with new disease indications, and potential safety concerns for drugs under development.

Targeted proteomic analysis of cognitive dysfunction in remitted major depressive disorder: Opportunities of multi-omics approaches towards predictive, preventive, and personalized psychiatry

In order to accelerate the understanding of pathophysiological mechanisms and clinical biomarker discovery and in psychiatry, approaches that integrate multiple -omics platforms are needed. We introduce a workflow that investigates a narrowly defined psychiatric phenotype, makes use of the potent and cost-effective discovery technology of gene expression microarrays, applies Weighted Gene Co-Expression Network Analysis (WGCNA) to better capture complex and polygenic traits, and finally explores gene expression findings on the proteomic level using targeted mass-spectrometry (MS) technologies. To illustrate the effectiveness of the workflow, we present a proteomic analysis of peripheral blood plasma from patient's remitted major depressive disorder (MDD) who experience ongoing cognitive deficits. We show that co-expression patterns previous detected on the transcript level could be replicated for plasma proteins, as could the module eigengene correlation with cognitive performance. Further, we demonstrate that functional analysis of multi-omics data has the potential to point to cellular mechanisms and candidate biomarkers for cognitive dysfunction in MDD, implicating cell cycle regulation by cyclin D3 (CCND3), regulation of protein processing in the endoplasmatic reticulum by Thioredoxin domain-containing protein 5 (TXND5), and modulation of inflammatory cytokines by Tripartite Motif Containing 26 (TRI26).

SIGNIFICANCE

This paper discusses how data from multiple -omics platforms can be integrated to accelerate biomarker discovery in psychiatry. Using the phenotype of cognitive impairment in remitted major depressive disorder (MDD) as an example, we show that the application of a systems biology approach - weighted gene co-expression network analysis (WGCNA) - in the discovery phase, and targeted proteomic follow-up of results, provides a structured avenue towards uncovering novel candidate markers and pathways for personalized clinical psychiatry.

Symptom practice guide for telephone assessment of patients with cancer treatment-related cardiotoxic dyspnea: Adaptation and evaluation of acceptability

BACKGROUND

Patients with cancer treatment-related cardiotoxicity, which may manifest as heart failure (HF), can present with dyspnea. Nurses frequently assess, triage and offer self-care strategies to patients experiencing dyspnea in both the cardiology and oncology settings. However, there are no known tools available for nurses to manage patients in the setting of cancer treatment-related cardiotoxicity. The objective of this study was to adapt and evaluate the acceptability of an evidence-informed symptom practice guide (SPG) for use by nurses over the telephone for the assessment, triage, and management of patients experiencing dyspnea due to cancer treatment-related cardiotoxicity.

METHODS

The CAN-IMPLEMENT© methodology guided this descriptive study. A systematic search was conducted in four databases to identify cardio-oncology and HF guidelines and systematic reviews. Screening was conducted by two reviewers, with data extracted into a recommendation matrix from eligible guidelines and systematic reviews on: assessment criteria, medications, and/or self-care strategies to manage dyspnea. Healthcare professionals with an expertise in oncology and/or cardiology were recruited using purposeful and snowball sampling. Evaluation of acceptability of the adapted SPG was gathered through semi-structured interviews and a survey with open- and closed-ended questions. Quantitative findings and participant feedback from the interviews and the open-ended survey questions were analyzed descriptively.

RESULTS

Of 490 citations, seven HF guidelines were identified. Evidence from these guidelines was added to the original SPG. Eleven healthcare professionals completed the interview and acceptability survey. The adapted SPG was iteratively revised three times during the interviews. The original SPG was adaptable, and participants indicated the adapted SPG was comprehensive, easy to follow, and would be useful in clinical practice.

CONCLUSIONS

This study highlights the lack of knowledge tools and available clinical practice guidelines to guide healthcare professionals to assess, triage and/or offer self-care strategies to patients with cancer treatment-related cardiotoxic dyspnea. Moreover, most nurses require assistance to differentiate among the various causes of dyspnea from oncology treatment in order to triage severity appropriately. Further research should focus on evaluating the validity of the adapted SPG in clinical practice.

Decision aids for patients considering total joint replacement: a cost-effectiveness analysis alongside a randomised controlled trial

BACKGROUND

Shared decision-making (SDM) is a key priority to improve patient-centred care, and can play an important role in helping patients decide whether to undergo total joint arthroplasty (TJA). Patient decision aids can support SDM; however, they may incur an upfront cost. We aimed to estimate the health and economic effects of patient decision aids for TJA.

METHODS

A cost-effectiveness analysis of a randomised controlled trial (RCT) with 2-year follow-up. 343 patients were recruited from two orthopedic screening clinics in Ottawa, Canada. Patients were randomized to either a patient decision aid plus surgeon preference report (decision aid) or usual care. Primary outcomes were costs (in 2014 CAD$), quality-adjusted life-years (QALYs), and the incremental cost-effectiveness ratio (ICER). Costs were calculated by multiplying self-reported resource use by unit costs. QALYs were calculated by mapping the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) to EuroQol 5-Dimension (EQ-5D) health utilities. Costs and QALYs were discounted at 5%. Multiple imputation was used to handle missing data, and bootstrapping was used to estimate uncertainty.

RESULTS

The sample comprised 167 intervention and 167 control group patients. The decision aid arm had fewer surgeries over the 2-year period thereby incurring a negative incremental cost of -$560 (95% CI: -$1358 to $426) per patient while providing 0.05 (95% CI: -0.04 to 0.13) additional QALYs per patient. Consequently, the decision aid arm was dominant.

CONCLUSION

The use of a patient decision aid was associated with fewer health care costs, while producing similar health outcomes.

CLINICAL TRIAL REGISTRATION NUMBER

CT00911638 (clinicaltrials.gov).

Cytokine levels in major depression are related to childhood trauma but not to recent stressors

BACKGROUND

Major depressive disorder (MDD) is a stress-related psychiatric disorder. A subgroup of MDD patients is characterized by increased inflammatory activation. We aimed to investigate whether increased inflammation particularly occurs in MDD patients with a history of stressful early or later life experiences.

METHODS

Serum levels of tumor necrosis factor alpha (TNF-α) and interleukin (IL)-6 were determined in N=214 MDD patients and N=180 healthy controls (HC). Childhood trauma (Childhood Trauma Questionnaire - CTQ), adverse life events of the past 12 months (List of Threatening Experiences Questionnaire - LTE-Q), and perceived stress in the past month (Perceived Stress Scale - PSS) were analyzed with regard to cytokine levels.

RESULTS

Pro-inflammatory cytokine levels were not related to global scores of adverse events or perceived stress covering different time points ranging from childhood to the past month. However, in the subgroup of traumatized MDD patients, higher severity of childhood sexual abuse was associated with higher levels of both IL-6 and TNF-α in a linear fashion.

CONCLUSIONS

Our data suggest a linear relationship between childhood sexual abuse and increased pro-inflammatory cytokine levels in MDD patients, while more recent stressful life events were not related to these inflammatory markers.

TNF receptors 1 and 2 exert distinct region-specific effects on striatal and hippocampal grey matter volumes (VBM) in healthy adults

Tumour necrosis factor alpha (TNFα) has been implicated in the pathophysiology of neurodegenerative and neuropsychiatric disease, with research highlighting a role for TNFα in hippocampal and striatal regulation. TNFα signals are primarily transduced by TNF receptors 1 and 2 (TNFR1 and TNFR2), encoded by TNFRSF1A and TNFRSF1B, which exert opposing effects on cell survival (TNFR1, neurodegenerative; TNFR2, neuroprotective). We therefore sought to explore the respective roles of TNFR1 and TNFR2 in the regulation of hippocampal and striatal morphology in an imaging genetics study. Voxel-based morphometry was used to analyse the associations between TNFRSF1A (rs4149576 and rs4149577) and TNFRSF1B (rs1061624) genotypes and grey matter structure. The final samples comprised a total of 505 subjects (mean age = 33.29, SD = 11.55 years; 285 females and 220 males) for morphometric analyses of rs1061624 and rs4149576, and 493 subjects for rs4149577 (mean age = 33.20, SD = 11.56 years; 281 females and 212 males). Analyses of TNFRSF1A single nucleotide polymorphisms (SNPs) rs4149576 and rs4149577 showed highly significant genotypic associations with striatal volume but not the hippocampus. Specifically, for rs4149576, G homozygotes were associated with reduced caudate nucleus volumes relative to A homozygotes and heterozygotes, whereas for rs4149577, reduced caudate volumes were observed in C homozygotes relative to T homozygotes and heterozygotes. Analysis of the TNFRSF1B SNP rs1061624 yielded a significant association with hippocampal but not with striatal volume, whereby G homozygotes were associated with increased volumes relative to A homozygotes and heterozygotes. Our findings indicate a role for TNFR1 in regulating striatal but not hippocampal morphology, as well as a complementary role for TNFR2 in hippocampal but not in striatal morphology.

A translational systems biology approach in both animals and humans identifies a functionally related module of accumbal genes involved in the regulation of reward processing and binge drinking in males

BACKGROUND

The mesolimbic dopamine system, composed primarily of dopaminergic neurons in the ventral tegmental area that project to striatal structures, is considered to be the key mediator of reinforcement-related mechanisms in the brain. Prompted by a genome-wide association meta-analysis implicating the Ras-specific guanine nucleotide-releasing factor 2 (RASGRF2) gene in the regulation of alcohol intake in men, we have recently shown that male Rasgrf2(-/-) mice exhibit reduced ethanol intake and preference accompanied by a perturbed mesolimbic dopamine system. We therefore propose that these mice represent a valid model to further elucidate the precise genes and mechanisms regulating mesolimbic dopamine functioning.

METHODS

Transcriptomic data from the nucleus accumbens (NAcc) of male Rasgrf2(-/-) mice and wild-type controls were analyzed by weighted gene coexpression network analysis (WGCNA). We performed follow-up genetic association tests in humans using a sample of male adolescents from the IMAGEN study characterized for binge drinking (n = 905) and ventral striatal activation during an fMRI reward task (n = 608).

RESULTS

The WGCNA analyses using accumbal transcriptomic data revealed 37 distinct "modules," or functionally related groups of genes. Two of these modules were significantly associated with Rasgrf2 knockout status: M5 (p < 0.001) and M6 (p < 0.001). In follow-up translational analyses we found that human orthologues for the M5 module were significantly (p < 0.01) enriched with genetic association signals for binge drinking in male adolescents. Furthermore, the most significant locus, originating from the EH-domain containing 4 (EHD4) gene (p < 0.001), was also significantly associated with altered ventral striatal activity in male adolescents performing an fMRI reward task (pempirical < 0.001).

LIMITATIONS

It was not possible to determine the extent to which the M5 module was dysregulated in Rasgrf2(-/-) mice by perturbed mesolimbic dopamine signalling or by the loss of Rasgrf2 function in the NAcc.

CONCLUSION

Taken together, our findings indicate that the accumbal M5 module, initially identified as being dysregulated in male Rasgrf2(-/-) mice, is also relevant for human alcohol-related phenotypes potentially through the modulation of reinforcement mechanisms in the NAcc. We therefore propose that the genes comprising this module represent important candidates for further elucidation within the context of alcohol-related phenotypes.

Impact of patient decision aids on appropriate and timely access to hip or knee arthroplasty for osteoarthritis: a randomized controlled trial

OBJECTIVE

To evaluate the effectiveness of patient decision aids (PtDA) compared to usual education on appropriate and timely access to total joint arthroplasty in patients with osteoarthritis.

METHOD

A randomized controlled trial (RCT) with patients undergoing orthopedic screening. Control and intervention arms received usual education; intervention arm also received a PtDA and a surgeon preference report. Wait times (primary outcome) were described using stratified Kaplan-Meier survival curves with patients censored at the time of death or loss to follow-up, and multivariable Cox proportional hazards regression. Secondary outcomes were compared using stratified Cochran-Mantel-Haenszel chi-squared tests.

RESULTS

343 patients were randomized to intervention (n = 174) or control (n = 169). The typical patient was 66 years old, retired, living with someone, and 51% had high school education or less. The intervention was associated with a trend towards reduction in wait time (hazard ratio (HR) 1.25, 95% confidence interval (CI) 0.99-1.60, P = 0.0653). Median wait times were 3 weeks shorter in intervention than in control at the community site with no difference at the academic site. Good decision quality was reached by 56.1% intervention and 44.5% control (Relative risk (RR) 1.25; 95% CI 1.00-1.56, P = 0.050). Surgery rates were 73.2% intervention and 80.5% controls (RR 0.91: 95% CI 0.81-1.03) with 12 intervention (7.3%) and eight control participants (4.9%) returning to have surgery within 2 years (P = 0.791).

CONCLUSION

Compared to controls, decision aid recipients had shorter wait times at one site, fewer surgeries, and were more likely to reach good decision quality, but overall effect was not statistically significant.

TRIALS REGISTRATION

The full trial protocol is available at ClinicalTrials.Gov (NCT00911638).

Evidence of an IFN-γ by early life stress interaction in the regulation of amygdala reactivity to emotional stimuli

INTRODUCTION

Since numerous studies have found that exposure to early life stress leads to increased peripheral inflammation and psychiatric disease, it is thought that peripheral immune activation precedes and possibly mediates the onset of stress-associated psychiatric disease. Despite early studies, IFNγ has received little attention relative to other inflammatory cytokines in the context of the pathophysiology of affective disorders. Neuroimaging endophenotypes have emerged recently as a promising means of elucidating these types of complex relationships including the modeling of the interaction between environmental factors and genetic predisposition. Here we investigate the GxE relationship between early-life stress and genetic variants of IFNγ on emotion processing.

METHODS

To investigate the impact of the relationship between genetic variants of IFNγ (rs1861494, rs2069718, rs2430561) and early life stress on emotion processing, a sample of healthy adults (n=409) undergoing an emotional faces paradigm in an fMRI study were genotyped and analysed. Information on early life stress was obtained via Childhood Trauma Questionnaire (CTQ).

RESULTS

A positive association between early life stress and amygdala reactivity was found. Specifically, the main effect of genotype of rs1861494 on amygdala reactivity indicates a higher neural response in C allele carriers compared to T homozygotes, while we did not find main effects of rs2069718 and rs2430561. Importantly, interaction analyses revealed a specific interaction between IFNγ genotype (rs1861494) and early life stress affecting amygdala reactivity to emotional faces, resulting from a positive association between CTQ scores and amygdala reactivity in C allele carriers while this association was absent in T homozygotes.

CONCLUSIONS

Our findings indicate that firstly the genetic variant of IFNγ (rs1861494) is involved with the regulation of amygdala reactivity to emotional stimuli and secondly, that this genetic variant moderates effects of early life stress on emotion processing. These findings reiterate the importance that inflammatory genes play in the interaction with early life stress and the regulation of emotion processing.

Multimodal imaging of a tescalcin (TESC)-regulating polymorphism (rs7294919)-specific effects on hippocampal gray matter structure

In two large genome-wide association studies, an intergenic single-nucleotide polymorphism (SNP; rs7294919) involved in TESC gene regulation has been associated with hippocampus volume. Further characterization of neurobiological effects of the TESC gene is warranted using multimodal brain-wide structural and functional imaging. Voxel-based morphometry (VBM8) was used in two large, well-characterized samples of healthy individuals of West-European ancestry (Münster sample, N=503; SHIP-TREND, N=721) to analyze associations between rs7294919 and local gray matter volume. In subsamples, white matter fiber structure was investigated using diffusion tensor imaging (DTI) and limbic responsiveness was measured by means of functional magnetic resonance imaging (fMRI) during facial emotion processing (N=220 and N=264, respectively). Furthermore, gene x environment (G × E) interaction and gene x gene interaction with SNPs from genes previously found to be associated with hippocampal size (FKBP5, Reelin, IL-6, TNF-α, BDNF and 5-HTTLPR/rs25531) were explored. We demonstrated highly significant effects of rs7294919 on hippocampal gray matter volumes in both samples. In whole-brain analyses, no other brain areas except the hippocampal formation and adjacent temporal structures were associated with rs7294919. There were no genotype effects on DTI and fMRI results, including functional connectivity measures. No G × E interaction with childhood maltreatment was found in both samples. However, an interaction between rs7294919 and rs2299403 in the Reelin gene was found that withstood correction for multiple comparisons. We conclude that rs7294919 exerts highly robust and regionally specific effects on hippocampal gray matter structures, but not on other neuropsychiatrically relevant imaging markers. The biological interaction between TESC and RELN pointing to a neurodevelopmental origin of the observed findings warrants further mechanistic investigations.

No evidence of DISC1-associated morphological changes in the hippocampus, anterior cingulate cortex, or striatum in major depressive disorder cases and healthy controls

BACKGROUND

DISC1 imaging genetics studies in healthy controls, schizophrenia, and bipolar disorder cases have revealed morphological changes in brain regions involved in the pathophysiology of psychiatric disease including the hippocampus, anterior cingulate cortex (ACC), and the striatum. However, many of these studies have yielded discordant findings so there is a need for replication. Furthermore, despite evidence from human genetic studies and animal models implicating DISC1 in major depressive disorder (MDD), a DISC1 imaging genetics study in MDD cases has yet to be published. Thus, using neuroimaging data from MDD cases and a large sample of healthy controls we aimed to identify morphological changes representing neurobiological mechanisms underlying the association between DISC1 and MDD.

METHODS

We utilized structural magnetic resonance imaging (sMRI) data from 512 healthy controls and 171 current MDD (SCID interview) cases, each with genotype data for non-synonymous DISC1 SNPs rs3738401, rs6675281, and rs821616.

RESULTS

Region of interest analyses failed to reveal DISC1-associated morphological changes in the hippocampus, ACC, or striatum in MDD patients and healthy controls. Whole brain exploratory analyses identified a nominally significant cluster mapping to the border of the precentral and postcentral gyri associated with rs821616 in healthy controls only (p(uncorrected)<0.001).

LIMITATIONS

We focused our analyses exclusively on three, but previously heavily studied, SNPs in DISC1.

CONCLUSIONS

Our findings suggest that morphological changes in the hippocampus, ACC, and/or striatum of MDD patients do not represent neurobiological mechanisms underlying the association between DISC1 and MDD. However, we urge replication in independent samples of MDD cases.