Imperial College London

Dr Ioanna (Joanna) Tzoulaki

Faculty of MedicineSchool of Public Health

Professor of Chronic Disease Epidemiology
 
 
 
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Contact

 

+44 (0)20 7594 3462i.tzoulaki

 
 
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Location

 

Building E - Sir Michael UrenWhite City Campus

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Summary

 

Publications

Publication Type
Year
to

303 results found

Kanai M, Andrews SJ, Cordioli M, Stevens C, Neale BM, Daly M, Ganna A, Pathak GA, Iwasaki A, Karjalainen J, Mehtonen J, Pirinen M, Chwialkowska K, Trankiem A, Balaconis MK, Veerapen K, Wolford BN, Ahmad HF, Andrews S, von Hohenstaufen Puoti KA, Boer C, Boua PR, Butler-Laporte G, Cadilla CL, Chwiałkowska K, Colombo F, Douillard V, Dueker N, Dutta AK, El-Sherbiny YM, Eltoukhy MM, Esmaeeli S, Faucon A, Fave M-J, Cadenas IF, Francescatto M, Francioli L, Franke L, Fuentes M, Durán RG, Cabrero DG, Harry EN, Jansen P, Szentpéteri JL, Kaja E, Kanai M, Kirk C, Kousathanas A, Krieger JE, Patel SK, Lemaçon A, Limou S, Lió P, Marouli E, Marttila MM, Medina-Gómez C, Michaeli Y, Migeotte I, Mondal S, Moreno-Estrada A, Moya L, Nakanishi T, Nasir J, Pasko D, Pearson NM, Pereira AC, Priest J, Prijatelj V, Prokić I, Teumer A, Várnai R, Romero-Gómez M, Roos C, Rosenfeld J, Ruolin L, Schulte EC, Schurmann C, Sedaghati-khayat B, Shaheen D, Shivanathan I, Sipeky C, Sirui Z, Striano P, Tanigawa Y, Remesal AU, Vadgama N, Vallerga CL, van der Laan S, Verdugo RA, Wang QS, Wei Z, Zainulabid UA, Zárate RN, Auton A, Shelton JF, Shastri AJ, Weldon CH, Filshtein-Sonmez T, Coker D, Symons A, Aslibekyan S, OConnell J, Ye C, Hatoum AS, Agrawal A, Bogdan R, Colbert SMC, Thompson WK, Fan CC, Johnson EC, Niazyan L, Davidyants M, Arakelyan A, Avetyan D, Bekbossynova M, Tauekelova A, Tuleutayev M, Sailybayeva A, Ramankulov Y, Zholdybayeva E, Dzharmukhanov J, Kassymbek K, Tsechoeva T, Turebayeva G, Smagulova Z, Muratov T, Khamitov S, Kwong ASF, Timpson NJ, Niemi MEK, Rahmouni S, Guntz J, Beguin Y, Cordioli M, Pigazzini S, Nkambule L, Georges M, Moutschen M, Misset B, Darcis G, Gofflot S, Bouysran Y, Busson A, Peyrassol X, Wilkin F, Pichon B, Smits G, Vandernoot I, Goffard J-C, Tiembe N, Morrison DR, Afilalo J, Mooser V, Richards JB, Rousseau S, Durand M, Butler-Laporte G, Forgetta V, Laurent L, Afrasiabi Z, Bouab M, Tselios C, Xue X, Afilalo M, Oliveira M, St-Cyr J, Boisclair A, Ragoussis J, Auld D, Kaufet al., 2023, A second update on mapping the human genetic architecture of COVID-19, Nature, Vol: 621, Pages: E7-E26, ISSN: 0028-0836

Journal article

Wood AC, Graca G, Gadgil M, Senn MK, Allison MA, Tzoulaki I, Greenland P, Ebbels T, Elliott P, Goodarzi MO, Tracy R, Rotter JI, Herrington Det al., 2023, Untargeted metabolomic analysis investigating links between unprocessed red meat intake and markers of inflammation., Am J Clin Nutr

BACKGROUND: Whether red meat consumption is associated with higher inflammation or confounded by increased adiposity remains unclear. Plasma metabolites capture the effects of diet after food is processed, digested, and absorbed and correlate with markers of inflammation, so they can help clarify diet-health relationships. OBJECTIVE: To identify whether any metabolites associated with red meat intake are also associated with inflammation. METHODS: A cross-sectional analysis of observational data from older adults (52.84% women, mean age 63 ± 0.3 y) participating in the MultiEthnic Study of Atherosclerosis. Dietary intake was assessed by food-frequency questionnaire, alongside C-reactive protein (CRP), interleukin-2, interleukin-6, fibrinogen, homocysteine, and tumor necrosis factor alpha, and untargeted proton nuclear magnetic resonance (1H NMR) metabolomic features. Associations between these variables were examined using linear regression models, adjusted for demographic factors, lifestyle behaviors, and body mass index (BMI). RESULTS: Neither processed nor unprocessed forms of red meat were associated with any markers of inflammation (all P > 0.01). However, again, in analyses that adjust for BMI, unprocessed red meat was inversely associated with spectral features representing the metabolite glutamine (sentinel hit: β = -0.09 ± 0.02, P = 2.0 × 10-5), an amino acid which was also inversely associated with CRP level (β = -0.11 ± 0.01, P = 3.3 × 10-10). CONCLUSIONS: Our analyses were unable to support a relationship between either processed or unprocessed red meat and inflammation, over and above any confounding by BMI. Glutamine, a plasma correlate of lower unprocessed red meat intake, was associated with lower CRP levels. The differences in diet-inflammation associations compared with diet metabolite-inflammation associations warrant further investigation to understand the extent that these arise from the following: 1

Journal article

Lagou V, Jiang L, Ulrich A, Zudina L, González KSG, Balkhiyarova Z, Faggian A, Maina JG, Chen S, Todorov PV, Sharapov S, David A, Marullo L, Mägi R, Rujan R-M, Ahlqvist E, Thorleifsson G, Gao Η, Εvangelou Ε, Benyamin B, Scott RA, Isaacs A, Zhao JH, Willems SM, Johnson T, Gieger C, Grallert H, Meisinger C, Müller-Nurasyid M, Strawbridge RJ, Goel A, Rybin D, Albrecht E, Jackson AU, Stringham HM, Corrêa IR, Farber-Eger E, Steinthorsdottir V, Uitterlinden AG, Munroe PB, Brown MJ, Schmidberger J, Holmen O, Thorand B, Hveem K, Wilsgaard T, Mohlke KL, Wang Z, GWA-PA Consortium, Shmeliov A, den Hoed M, Loos RJF, Kratzer W, Haenle M, Koenig W, Boehm BO, Tan TM, Tomas A, Salem V, Barroso I, Tuomilehto J, Boehnke M, Florez JC, Hamsten A, Watkins H, Njølstad I, Wichmann H-E, Caulfield MJ, Khaw K-T, van Duijn CM, Hofman A, Wareham NJ, Langenberg C, Whitfield JB, Martin NG, Montgomery G, Scapoli C, Tzoulaki I, Elliott P, Thorsteinsdottir U, Stefansson K, Brittain EL, McCarthy MI, Froguel P, Sexton PM, Wootten D, Groop L, Dupuis J, Meigs JB, Deganutti G, Demirkan A, Pers TH, Reynolds CA, Aulchenko YS, Kaakinen MA, Jones B, Prokopenko I, Meta-Analysis of Glucose and Insulin-Related Traits Consortium MAGICet al., 2023, GWAS of random glucose in 476,326 individuals provide insights into diabetes pathophysiology, complications and treatment stratification., Nat Genet, Vol: 55, Pages: 1448-1461

Conventional measurements of fasting and postprandial blood glucose levels investigated in genome-wide association studies (GWAS) cannot capture the effects of DNA variability on 'around the clock' glucoregulatory processes. Here we show that GWAS meta-analysis of glucose measurements under nonstandardized conditions (random glucose (RG)) in 476,326 individuals of diverse ancestries and without diabetes enables locus discovery and innovative pathophysiological observations. We discovered 120 RG loci represented by 150 distinct signals, including 13 with sex-dimorphic effects, two cross-ancestry and seven rare frequency signals. Of these, 44 loci are new for glycemic traits. Regulatory, glycosylation and metagenomic annotations highlight ileum and colon tissues, indicating an underappreciated role of the gastrointestinal tract in controlling blood glucose. Functional follow-up and molecular dynamics simulations of lower frequency coding variants in glucagon-like peptide-1 receptor (GLP1R), a type 2 diabetes treatment target, reveal that optimal selection of GLP-1R agonist therapy will benefit from tailored genetic stratification. We also provide evidence from Mendelian randomization that lung function is modulated by blood glucose and that pulmonary dysfunction is a diabetes complication. Our investigation yields new insights into the biology of glucose regulation, diabetes complications and pathways for treatment stratification.

Journal article

Hunter WG, Smith AG, Pinto RC, Saldanha S, Gangwar A, Pahlavani M, Deodhar S, Wilkins J, Pandey A, Herrington D, Greenland P, Tzoulaki I, Rohatgi Aet al., 2023, Metabolomic Profiling of Cholesterol Efflux Capacity in a Multiethnic Population: Insights From MESA., Arterioscler Thromb Vasc Biol

BACKGROUND: Impaired cholesterol efflux capacity (CEC) is a novel lipid metabolism trait associated with atherosclerotic cardiovascular disease. Mechanisms underlying CEC variation are unknown. We evaluated associations of circulating metabolites with CEC to advance understanding of metabolic pathways involved in cholesterol efflux regulation. METHODS: Participants enrolled in the MESA (Multi-Ethnic Study of Atherosclerosis) who underwent nuclear magnetic resonance metabolome profiling and CEC measurement (N=3543) at baseline were included. Metabolite associations with CEC were evaluated using standard linear regression analyses. Repeated ElasticNet and multilayer perceptron regression were used to assess metabolite profile predictive performance for CEC. Features important for CEC prediction were identified using Shapley Additive Explanations values. RESULTS: Greater CEC was significantly associated with metabolite clusters composed of the largest-sized particle subclasses of VLDL (very-low-density lipoprotein) and HDL (high-density lipoprotein), as well as their constituent apo A1, apo A2, phospholipid, and cholesterol components (β=0.072-0.081; P<0.001). Metabolite profiles had poor accuracy for predicting in vitro CEC in linear and nonlinear analyses (R2<0.02; Spearman ρ<0.18). The most important feature for CEC prediction was race, with Black participants having significantly lower CEC compared with other races. CONCLUSIONS: We identified independent associations among CEC, the largest-sized particle subclasses of VLDL and HDL, and their constituent apolipoproteins and lipids. A large proportion of variation in CEC remained unexplained by metabolites and traditional clinical risk factors, supporting further investigation into genomic, proteomic, and phospholipidomic determinants of CEC.

Journal article

Gill D, Woolf B, Zagkos L, Cronje HT, Tzoulaki Iet al., 2023, The cardiovascular efficacy of lipid-lowering drug targets is not entirely explained by apolipoprotein B reduction: Mendelian randomization evidence, Circulation: Genomic and Precision Medicine, ISSN: 2574-8300

Journal article

Wood AC, Goodarzi MO, Senn MK, Gadgil MD, Graca G, Allison MA, Tzoulaki I, Mi MY, Greenland P, Ebbels T, Elliott P, Tracy RP, Herrington DM, Rotter JIet al., 2023, Associations between Metabolomic Biomarkers of Avocado Intake and Glycemia in the Multi-Ethnic Study of Atherosclerosis., J Nutr

BACKGROUND: Avocado consumption is linked to better glucose homeostasis, but small associations suggest potential population heterogeneity. Metabolomic data capture the effects of food intake after digestion and metabolism, thus accounting for individual differences in these processes. OBJECTIVES: To identify metabolomic biomarkers of avocado intake and to examine their associations with glycemia. METHODS: Baseline data from 6224 multi-ethnic older adults (62% female) included self-reported avocado intake, fasting glucose and insulin, and untargeted plasma proton nuclear magnetic resonance metabolomic features (metabolomic data were available for a randomly selected subset; N = 3438). Subsequently, incident type 2 diabetes (T2D) was assessed over an ∼18 y follow-up period. A metabolome-wide association study of avocado consumption status (consumer compared with nonconsumer) was conducted, and the relationship of these features with glycemia via cross-sectional associations with fasting insulin and glucose and longitudinal associations with incident T2D was examined. RESULTS: Three highly-correlated spectral features were associated with avocado intake at metabolome-wide significance levels (P < 5.3 ∗ 10-7) and combined into a single biomarker. We did not find evidence that these features were additionally associated with overall dietary quality, nor with any of 47 other food groups (all P > 0.001), supporting their suitability as a biomarker of avocado intake. Avocado intake showed a modest association only with lower fasting insulin (β = -0.07 +/- 0.03, P = 0.03), an association that was attenuated to nonsignificance when additionally controlling for body mass index (kg/m2). However, our biomarker of avocado intake was strongly associated with lower fasting glucose (β = -0.22 +/- 0.02, P < 2.0 ∗ 10-16), lower fasting insulin (β = -0.17 +/- 0.02, P < 2.0 ∗ 10-16), and a lower incidence of T2D (hazard ratio: 0.68; 0

Journal article

Gadgil MD, Wood AC, Karaman I, Graça G, Tzoulaki I, Zhong VW, Greenland P, Kanaya AM, Herrington DMet al., 2023, Metabolomic Profile of the Healthy Eating Index-2015 in the Multiethnic Study of Atherosclerosis., J Nutr, Vol: 153, Pages: 2174-2180

BACKGROUND: Poor diet quality is a risk factor for type 2 diabetes and cardiovascular disease. However, knowledge of metabolites marking adherence to Dietary Guidelines for Americans (2015 version) are limited. OBJECTIVES: The goal was to determine a pattern of metabolites associated with the Healthy Eating Index (HEI)-2015, which measures adherence to the Dietary Guidelines for Americans. METHODS: The analysis examined 3557 adult men and women from the longitudinal cohort Multiethnic Study of Atherosclerosis (MESA), without known cardiovascular disease and with complete dietary data. Fasting serum specimens and diet and demographic questionnaires were assessed at baseline. Untargeted 1H 1-dimensional nuclei magnetic resonance spectroscopy (600 MHz) was used to generate metabolomics and lipidomics. A metabolome-wide association study specified each spectral feature as outcomes, HEI-2015 score as predictor, adjusting for age, sex, race, and study site in linear regression analyses. Subsequently, hierarchical clustering defined the discrete groups of correlated nuclei magnetic resonance features associated with named metabolites, and the linear regression analysis assessed for associations with HEI-2015 total and component scores. RESULTS: The sample included 50% women with an mean age of 63 years, with 40% identifying as White, 23% as Black, 24% as Hispanic, and 13% as Chinese American. The mean HEI-2015 score was 66. The metabolome-wide association study identified 179 spectral features significantly associated with HEI-2015 score. The cluster analysis identified 7 clusters representing 4 metabolites; HEI-2015 score was significantly associated with all. HEI-2015 score was associated with proline betaine [β = 0.12 (SE = 0.02); P = 4.70 × 10-13] and was inversely related to proline [β = -0.13 (SE = 0.02); P = 4.45 × 10-14], 1,5 anhydrosorbitol [β = -0.08 (SE = 0.02); P = 4.37 × 10-7] and unsaturated fatty acyl chains [β = 0.08 (S

Journal article

Giontella A, Zagkos L, Geybels M, Larsson SC, Tzoulaki I, Mantzoros CS, Andersen B, Gill D, Cronjé HTet al., 2023, Renoprotective effects of genetically proxied fibroblast growth factor 21: Mendelian randomization, proteome-wide and metabolome-wide association study., Metabolism, Vol: 145

BACKGROUND: Fibroblast growth factor 21 (FGF21) has demonstrated efficacy for reducing liver fat and reversing non-alcoholic steatohepatitis in phase 2 clinical trials. It is also postulated to have anti-fibrotic effects and therefore may be amenable to repurposing for the prevention and treatment of chronic kidney disease (CKD). METHODS: We leverage a missense genetic variant, rs739320 in the FGF21 gene, that associates with magnetic resonance imaging-derived liver fat as a clinically validated and biologically plausible instrumental variable for studying the effects of FGF21 analogs. Performing Mendelian randomization, we ascertain associations between instrumented FGF21 and kidney phenotypes, cardiometabolic disease risk factors, as well as the circulating proteome (Somalogic, 4907 aptamers) and metabolome (Nightingale platform, 249 metabolites). RESULTS: We report consistent renoprotective associations of genetically proxied FGF21 effect, including higher glomerular filtration rates (p = 1.9 × 10-4), higher urinary sodium excretion (p = 5.1 × 10-11), and lower urine albumin-creatinine ratio (p = 3.6 × 10-5). These favorable effects translated to lower CKD risk (odds ratio per rs739320 C-allele, 0.96; 95%CI, 0.94-0.98; p = 3.2 × 10-4). Genetically proxied FGF21 effect was also associated with lower fasting insulin, waist-to-hip ratio, blood pressure (systolic and diastolic BP, p < 1.0 × 10-07) and blood lipid (low-density lipoprotein cholesterol, triglycerides and apolipoprotein B, p < 6.5 × 10-24) profiles. The latter associations are replicated in our metabolome-wide association study. Proteomic perturbations associated with genetically predicted FGF21 effect were consistent with fibrosis reduction. CONCLUSION: This study highlights the pleiotropic effects of genetically proxied FGF21 and supports a re

Journal article

Zheng B, Su B, Ahmadi-Abhari S, Kapogiannis D, Tzoulaki I, Riboli E, Middleton Let al., 2023, Dementia risk in patients with type 2 diabetes: Comparing metformin with no pharmacological treatment., Alzheimers Dement

INTRODUCTION: Metformin has been suggested as a therapeutic agent for dementia, but the relevant evidence has been partial and inconsistent. METHODS: We established a national cohort of 210,237 type 2 diabetes patients in the UK Clinical Practice Research Datalink. Risks of incident dementia were compared between metformin initiators and those who were not prescribed any anti-diabetes medication during follow-up. RESULTS: Compared with metformin initiators (n = 114,628), patients who received no anti-diabetes medication (n = 95,609) had lower HbA1c and better cardiovascular health at baseline. Both Cox regression and propensity score weighting analysis showed metformin initiators had lower risk of dementia compared to those non-users (adjusted hazard ratio = 0.88 [95% confidence interval: 0.84-0.92] and 0.90 [0.84-0.96]). Patients on long-term metformin treatment had an even lower risk of dementia. DISCUSSION: Metformin may act beyond its glycemic effect and reduce dementia risk to an even lower level than that of patients with milder diabetes and better health profiles. HIGHLIGHTS: Metformin initiators had a significantly lower risk of dementia compared with patients not receiving anti-diabetes medication. Compared with metformin initiators, diabetes patients not receiving pharmacological treatment had better glycemic profiles at baseline and during follow-up. Patients on long-term metformin treatment had an even lower risk of subsequent dementia incidence. Metformin may act beyond its effect on hyperglycemia and has the potential of being repurposed for dementia prevention.

Journal article

Rapti I, Asimakopoulos A, Liontos A, Kosmidou M, Christaki E, Biros D, Milionis O, Tsourlos S, Ntotsikas E, Ntzani E, Evangelou E, Gartzonika K, Georgiou I, Tzoulaki I, Tsilidis K, Milionis Het al., 2023, Association of patient characteristics with clinical outcomes in a cohort of hospitalised patients with SARS-CoV-2 infection in a Greek referral centre for COVID-19 - Corrigendum., Epidemiol Infect, Vol: 151

Journal article

Liontos A, Asimakopoulos A-G, Markopoulos GS, Biros D, Athanasiou L, Tsourlos S, Dova L, Rapti I-C, Tsiakas I, Ntzani E, Evangelou E, Tzoulaki I, Tsilidis K, Vartholomatos G, Dounousi E, Milionis H, Christaki Eet al., 2023, Correlation of Lymphocyte Subpopulations, Clinical Features and Inflammatory Markers during Severe COVID-19 Onset., Pathogens, Vol: 12, ISSN: 2076-0817

BACKGROUND: Dysregulation of the immune response in the course of COVID-19 has been implicated in critical outcomes. Lymphopenia is evident in severe cases and has been associated with worse outcomes since the early phases of the pandemic. In addition, cytokine storm has been associated with excessive lung injury and concomitant respiratory failure. However, it has also been hypothesized that specific lymphocyte subpopulations (CD4 and CD8 T cells, B cells, and NK cells) may serve as prognostic markers for disease severity. The aim of this study was to investigate possible associations of lymphocyte subpopulations alterations with markers of disease severity and outcomes in patients hospitalized with COVID-19. MATERIALS/METHODS: A total of 42 adult hospitalized patients were included in this study, from June to July 2021. Flow-cytometry was used to calculate specific lymphocyte subpopulations on day 1 (admission) and on day 5 of hospitalization (CD45, CD3, CD3CD8, CD3CD4, CD3CD4CD8, CD19, CD16CD56, CD34RA, CD45RO). Markers of disease severity and outcomes included: burden of disease on CT (% of affected lung parenchyma injury), C-reactive protein and interleukin-6 levels. PO2/FiO2 ratio and differences in lymphocytes subsets between two timepoints were also calculated. Logistic and linear regressions were used for the analyses. All analyses were performed using Stata (version 13.1; Stata Corp, College Station, TX, USA). RESULTS: Higher levels of CD16CD56 cells (Natural Killer cells) were associated with higher risk of lung injury (>50% of lung parenchyma). An increase in CD3CD4 and CD4RO cell count difference between day 5 and day 1 resulted in a decrease of CRP difference between these timepoints. On the other hand, CD45RARO difference was associated with an increase in the difference of CRP levels between the two timepoints. No other significant differences were found in the rest of the lymphocyte subpopulations. CONCLUSIONS: Despite a low patient number, this

Journal article

Chalitsios CV, Tsilidis KK, Tzoulaki I, 2023, Response to comment on "Psoriasis and COVID-19: A bidirectional Mendelian randomization study"., J Am Acad Dermatol, Vol: 88

Journal article

Chalitsios CV, Georgiou A, Bouras E, Evangelou E, Gill D, Tsilidis KK, Tzoulaki Iet al., 2023, Investigating modifiable pathways in psoriasis: A Mendelian randomization study., J Am Acad Dermatol, Vol: 88, Pages: 593-601

BACKGROUND: Potentially modifiable risk factors have previously been investigated only in conventional observational studies. OBJECTIVE: To assess whether genetically predicted exposures to modifiable factors are associated with the risk of psoriasis. METHODS: Two-sample Mendelian randomization (MR) analysis. RESULTS: An increased risk of psoriasis was noted for genetically predicted lifetime smoking index (odds ratio [OR]MR-IVW = 2.11; 95% confidence interval [CI], 1.28-3.51), childhood (OR MR-IVW = 1.40; 95% CI, 1.14-1.71) and adult body mass index (OR MR-IVW = 1.63; 95% CI, 1.32-2), waist (OR IVW = 1.86; 95% CI, 1.31-2.64), and hip circumference (OR MR-IVW = 1.55; 95% CI, 1.15-2.07). Protective association was also reported between genetically predicted longer sleep duration (OR MR-IVW = 0.56; 95% CI 0.37-0.84) and increased years of education (OR MR-IVW = 0.78; 95% CI, 0.62-0.98). This effect of education persisted in multivariable MR after adjusting for genetic predictors of smoking and adult body mass index (ORMVMR-IVW = 0.72; 95% CI, 0.56-0.92). LIMITATIONS: It was not possible to stratify for psoriasis severity. CONCLUSION: Smoking cessation and prevention of obesity are important strategies for decreasing the incidence of psoriasis. Similarly, targeting education inequality is expected to lead further to reductions in cases of psoriasis.

Journal article

Sud A, Horton RH, Hingorani AD, Tzoulaki I, Turnbull C, Houlston RS, Lucassen Aet al., 2023, Realistic expectations are key to realising the benefits of polygenic scores., BMJ: British Medical Journal, Vol: 380, Pages: 1-7, ISSN: 0959-535X

We must not let enthusiasm around polygenic scores allow us to forget other factors that are bigger, more modifiable, and relevant for everyone, argue Amit Sud, Rachel Horton, and colleagues

Journal article

Huang J, Gill D, Zuber V, Matthews PAUL, Elliott PAUL, Tzoulaki I, Dehghan ABBASet al., 2023, Circulatory proteins relate cardiovascular disease to cognitive performance: a Mendelian randomisation study, Frontiers in Genetics, Vol: 14, Pages: 1-11, ISSN: 1664-8021

Background and objectives: Mechanistic research suggests synergistic effects of cardiovascular disease (CVD) and dementia pathologies on cognitive decline. Interventions targeting proteins relevant to shared mechanisms underlying CVD and dementia could also be used for the prevention of cognitive impairment.Methods: We applied Mendelian randomisation (MR) and colocalization analysis to investigate the causal relationships of 90 CVD-related proteins measured by the Olink CVD I panel with cognitive traits. Genetic instruments for circulatory protein concentrations were obtained using a meta-analysis of genome-wide association studies (GWAS) from the SCALLOP consortium (N = 17,747) based on three sets of criteria: 1) protein quantitative trait loci (pQTL); 2) cis-pQTL (pQTL within ±500 kb from the coding gene); and 3) brain-specific cis-expression QTL (cis-eQTL) which accounts for coding gene expression based on GTEx8. Genetic associations of cognitive performance were obtained from GWAS for either: 1) general cognitive function constructed using Principal Component Analysis (N = 300,486); or, 2) g Factor constructed using genomic structural equation modelling (N = 11,263–331,679). Findings for candidate causal proteins were replicated using a separate protein GWAS in Icelanders (N = 35,559).Results: A higher concentration of genetically predicted circulatory myeloperoxidase (MPO) was nominally associated with better cognitive performance (p < 0.05) using different selection criteria for genetic instruments. Particularly, brain-specific cis-eQTL predicted MPO, which accounts for protein-coding gene expression in brain tissues, was associated with general cognitive function (βWald = 0.22, PWald = 2.4 × 10−4). The posterior probability for colocalization (PP.H4) of MPO pQTL with the g Factor was 0.577. Findings for MPO were replicated using the Icelandic GWAS. Although we did not find evidence for colocalization, we found that higher gene

Journal article

Zhao Y, Zhang H, Liu X, Desloge A, Wang Q, Zhao S, Song L, Tzoulaki Iet al., 2023, The prevalence of cardiometabolic multimorbidity and its associations with health outcomes among women in China, FRONTIERS IN CARDIOVASCULAR MEDICINE, Vol: 10, ISSN: 2297-055X

Journal article

Kojouri M, Pinto R, Mustafa R, Huang J, He G, Elliott P, Tzoulaki I, Dehghan Aet al., 2023, Metabolome-wide association study on physical activity, Scientific Reports, Vol: 13, Pages: 1-9, ISSN: 2045-2322

The underlying mechanisms linking physical activity to better health are not fully understood. Here we examined the associations between physical activity and small circulatory molecules, the metabolome, to highlight relevant biological pathways. We examined plasma metabolites associated with self-reported physical activity among 2217 participants from the Airwave Health Monitoring Study. Metabolic profiling was conducted using the mass spectrometry-based Metabolon platform (LC/GC–MS), measuring 828 known metabolites. We replicated our findings in an independent subset of the study (n = 2971) using untargeted LC–MS. Mendelian randomisation was carried out to investigate potential causal associations between physical activity, body mass index, and metabolites. Higher vigorous physical activity was associated (P < 0.05/828 = 6.03 × 10–5) with circulatory levels of 28 metabolites adjusted for age, sex and body mass index. The association was inverse for glutamate and diacylglycerol lipids, and direct for 3–4-hydroxyphenyllactate, phenyl lactate (PLA), alpha-hydroxy isovalerate, tiglylcarnitine, alpha-hydroxyisocaproate, 2-hydroxy-3-methylvalerate, isobutyrylcarnitine, imidazole lactate, methionine sulfone, indole lactate, plasmalogen lipids, pristanate and fumarate. In the replication panel, we found 23 untargeted LC–MS features annotated to the identified metabolites, for which we found nominal associations with the same direction of effect for three features annotated to 1-(1-enyl-palmitoyl)-2-oleoyl-GPC (P-16:0/18:1), 1-(1-enyl-palmitoyl)-2-linoleoyl-GPC (P-16:0/18:2), 1-stearoyl-2-dihomo-linolenoyl-GPC (18:0/20:3n3 or 6). Using Mendelian randomisation, we showed a potential causal relationship between body mass index and three identified metabolites. Circulatory metabolites are associated with physical activity and may play a role in mediating its health effects.

Journal article

Huang J, Su B, Karhunen V, Gill D, Zuber V, Ahola-Olli A, Palaniswamy S, Auvinen J, Herzig K-H, Keinänen-Kiukaanniemi S, Salmi M, Jalkanen S, Lehtimäki T, Salomaa V, Raitakari OT, Matthews PM, Elliott P, Tsilidis KK, Jarvelin M-R, Tzoulaki I, Dehghan Aet al., 2023, Inflammatory diseases, inflammatory biomarkers, and Alzheimer disease: an observational analysis and mendelian randomization, Neurology, Vol: 100, Pages: e568-e581, ISSN: 0028-3878

OBJECTIVES: Whether chronic autoimmune inflammatory diseases causally affect the risk of AD is controversial. We characterised the relationship between inflammatory diseases and the risk of AD and explore the role of circulating inflammatory biomarkers in the relationships between inflammatory diseases and AD. METHODS: We performed observational analyses for chronic autoimmune inflammatory diseases and risk of AD using data from 2,047,513 participants identified in the UK Clinical Practice Research Datalink (CPRD). Using data of a total of more than 1,100,000 individuals from 15 large scale genome-wide association study (GWAS) datasets, we performed two-sample Mendelian randomisation (MR) to investigate the relationships between chronic autoimmune inflammatory diseases, circulating inflammatory biomarker levels, and risk of AD. RESULTS: Cox regression models using CPRD data showed that overall incidence of AD was higher among patients with inflammatory bowel disease (IBD) (hazard ratio (HR)=1.17; 95%CI 1.15 to 1.19; P-value=2.1×10-4), other inflammatory polyarthropathies & systematic connective tissue disorders (OID) (HR=1.13; 95%CI 1.12 to 1.14; P-value=8.6×10-5), psoriasis (HR=1.13; 95%CI 1.10 to 1.16; P-value=2.6×10-4), rheumatoid arthritis (RA) (HR=1.08; 95%CI 1.06 to 1.11; P-value=4.0×10-4), and multiple sclerosis (MS) (HR=1.06; 95%CI 1.04 to 1.07; P-value=2.8×10-4) compared to the age (± 5 years) and sex-matched comparison groups free from all inflammatory diseases under investigation. Bidirectional MR analysis identified relationships between chronic autoimmune inflammatory diseases and circulating inflammatory biomarkers. Particularly, circulating monokine induced by gamma interferon (MIG) level was suggestively associated with a higher risk of AD (odds ratio from inverse variance weighted (ORIVW)=1.23; 95%CI 1.06 to 1.42; PIVW=0.007), and lower risk of Crohn's disease (ORIVW=0.73; 95%CI -0.62, 0.86; PIVW=1.3×10

Journal article

Ryan D, Karhunen V, Su B, Traylor M, Richardson TG, Burgess S, Tzoulaki I, Gill Det al., 2023, Genetic evidence for protective effects of angiotensin converting enzyme against Alzheimer's disease but not other neurodegenerative diseases, Pharmacology Annual Meeting, Publisher: WILEY, Pages: 565-567, ISSN: 0007-1188

Conference paper

Papandreou C, Papagiannopoulos C, Koutsonida M, Kanellopoulou A, Markozannes G, Polychronidis G, Tzakos AG, Fragkiadakis GA, Evangelou E, Ntzani E, Tzoulaki I, Aretouli E, Tsilidis KKet al., 2023, Mediterranean diet related metabolite profiles and cognitive performance., Clinical Nutrition, Vol: 42, Pages: 173-181, ISSN: 0261-5614

BACKGROUND & AIMS: Evidence suggests that adherence to the Mediterranean diet (MedDiet) affects human metabolism and may contribute to better cognitive performance. However, the underlying mechanisms are not clear. OBJECTIVE: We generated a metabolite profile for adherence to MedDiet and evaluated its cross-sectional association with aspects of cognitive performance. METHODS: A total of 1250 healthy Greek middle-aged adults from the Epirus Health Study cohort were included in the analysis. Adherence to the MedDiet was assessed using the 14-point Mediterranean Diet Adherence Screener (MEDAS); cognition was measured using the Trail Making Test, the Verbal Fluency test and the Logical Memory test. A targeted metabolite profiling (n = 250 metabolites) approach was applied, using a high-throughput nuclear magnetic resonance platform. We used elastic net regularized regressions, with a 10-fold cross-validation procedure, to identify a metabolite profile for MEDAS. We evaluated the associations of the identified metabolite profile and MEDAS with cognitive tests, using multivariable linear regression models. RESULTS: We identified a metabolite profile composed of 42 metabolites, mainly lipoprotein subclasses and fatty acids, significantly correlated with MedDiet adherence (Pearson r = 0.35, P-value = 5.5 × 10-37). After adjusting for known risk factors and accounting for multiple testing, the metabolite profile and MEDAS were not associated with the cognitive tests. CONCLUSIONS: A plasma metabolite profile related to better adherence to the MedDiet was not associated with the tested aspects of cognitive performance, in a middle-aged Mediterranean population.

Journal article

Elliott J, Bodinier B, Whitaker M, Tzoulaki I, Elliott P, Chadeau-Hyam Met al., 2023, Improving cardiovascular risk prediction beyond pooled cohort equations: a prospective cohort of 304,356 participants

<jats:title>Abstract</jats:title><jats:sec><jats:title>Background</jats:title><jats:p>Pooled Cohort Equations (PCE) are used to predict cardiovascular disease (CVD) risk. Inclusion of other variables may improve risk prediction.</jats:p></jats:sec><jats:sec><jats:title>Objective</jats:title><jats:p>Identify variables improving CVD risk prediction beyond recalibrated PCE.</jats:p></jats:sec><jats:sec><jats:title>Design</jats:title><jats:p>Prospective cohort study; sex-stratified Cox survival models with LASSO stability selection to predict CVD in non-overlapping subsets: variable selection (40%), model training (30%) and testing (30%).</jats:p></jats:sec><jats:sec><jats:title>Setting</jats:title><jats:p>UK population.</jats:p></jats:sec><jats:sec><jats:title>Participants</jats:title><jats:p>UK Biobank: 121,724 and 182,632 healthy men and women, respectively, aged 38-73 years at baseline.</jats:p></jats:sec><jats:sec><jats:title>Measurements</jats:title><jats:p>Personal/family medical history; lifestyle factors; genetic, biochemical, hematological, and metabolomic blood markers. Outcomes were incident hospitalization or mortality from CVD.</jats:p></jats:sec><jats:sec><jats:title>Results</jats:title><jats:p>There were 11,899 (men) and 9,110 (women) incident CVD cases with median 12.1 years follow-up. Variables selected for both men and women were: age, albumin, antihypertensive medication, apolipoprotein B, atrial fibrillation, C-reactive protein, current smoker, cystatin C, family history of coronary artery disease, glycated hemoglobin, polygenic risk score (PRS) for CVD and systolic blood pressure. Also selected: apolipoprotein A1, lipoprotein(a), white blood cell count, deprivation index (men); triglycerides (women).

Journal article

Garcia-Segura ME, Durainayagam BR, Liggi S, Graça G, Jimenez B, Dehghan A, Tzoulaki I, Karaman I, Elliott P, Griffin JLet al., 2023, Pathway-based integration of multi-omics data reveals lipidomics alterations validated in an Alzheimer´s Disease mouse model and risk loci carriers, Journal of Neurochemistry, Vol: 164, Pages: 57-76, ISSN: 0022-3042

Alzheimer´s Disease (AD) is a highly prevalent neurodegenerative disorder. Despite increasing evidence of the importance of metabolic dysregulation in AD, the underlying metabolic changes that may impact amyloid plaque formation are not understood, particularly for late onset AD. This study analyzed genome-wide association studies (GWAS), transcriptomics and proteomics data obtained from several data repositories to obtain differentially expressed (DE) multi-omics elements in mouse models of AD. We characterized the metabolic modulation in these datasets using gene ontology, transcription factor, pathway, and cell-type enrichment analyses. A predicted lipid signature was extracted from genome-scale metabolic networks (GSMN) and subsequently validated in a lipidomic dataset derived from cortical tissue of ABCA-7 null mice, a mouse model of one of the genes associated with late onset AD. Moreover, a metabolome-wide association study (MWAS) was performed to further characterize the association between dysregulated lipid metabolism in human blood serum and genes associated with AD risk. We found 203 DE transcripts, 164 DE proteins and 58 DE GWAS-derived mouse orthologs associated with significantly enriched metabolic biological processes. Lipid and bioenergetics metabolic pathways were significantly over-represented across the AD multi-omics datasets. Microglia and astrocytes were significantly enriched in the lipid-predominant AD-metabolic transcriptome. We also extracted a predicted lipid signature that was validated and robustly modelled class separation in the ABCA7 mice cortical lipidome, with 11 of these lipid species exhibiting statistically significant modulations. MWAS revealed 298 AD single nucleotide polymorphisms (SNP)-metabolite associations, of which 70% corresponded to lipid classes. These results support the importance of lipid metabolism dysregulation in AD and highlight the suitability of mapping AD multi-omics data into GSMNs to identify metabol

Journal article

Zagkos L, Dib M-J, Pinto R, Gill D, Koskeridis F, Drenos F, Markozannes G, Elliott P, Zuber V, Tsilidis K, Dehghan A, Tzoulaki Iet al., 2022, Associations of genetically predicted fatty acid levels across the phenome: a mendelian randomisation study, PLoS Medicine, Vol: 19, ISSN: 1549-1277

BACKGROUND: Fatty acids are important dietary factors that have been extensively studied for their implication in health and disease. Evidence from epidemiological studies and randomised controlled trials on their role in cardiovascular, inflammatory, and other diseases remains inconsistent. The objective of this study was to assess whether genetically predicted fatty acid concentrations affect the risk of disease across a wide variety of clinical health outcomes. METHODS AND FINDINGS: The UK Biobank (UKB) is a large study involving over 500,000 participants aged 40 to 69 years at recruitment from 2006 to 2010. We used summary-level data for 117,143 UKB samples (base dataset), to extract genetic associations of fatty acids, and individual-level data for 322,232 UKB participants (target dataset) to conduct our discovery analysis. We studied potentially causal relationships of circulating fatty acids with 845 clinical diagnoses, using mendelian randomisation (MR) approach, within a phenome-wide association study (PheWAS) framework. Regression models in PheWAS were adjusted for sex, age, and the first 10 genetic principal components. External summary statistics were used for replication. When several fatty acids were associated with a health outcome, multivariable MR and MR-Bayesian method averaging (MR-BMA) was applied to disentangle their causal role. Genetic predisposition to higher docosahexaenoic acid (DHA) was associated with cholelithiasis and cholecystitis (odds ratio per mmol/L: 0.76, 95% confidence interval: 0.66 to 0.87). This was supported in replication analysis (FinnGen study) and by the genetically predicted omega-3 fatty acids analyses. Genetically predicted linoleic acid (LA), omega-6, polyunsaturated fatty acids (PUFAs), and total fatty acids (total FAs) showed positive associations with cardiovascular outcomes with support from replication analysis. Finally, higher genetically predicted levels of DHA (0.83, 0.73 to 0.95) and omega-3 (0.83, 0.75 to 0.

Journal article

Charpignon M-L, Vakulenko-Lagun B, Zheng B, Magdamo C, Su B, Evans K, Rodriguez S, Sokolov A, Boswell S, Sheu Y-H, Somai M, Middleton L, Hyman BT, Betensky RA, Finkelstein SN, Welsch RE, Tzoulaki I, Blacker D, Das S, Albers MWet al., 2022, Causal inference in medical records and complementary systems pharmacology for metformin drug repurposing towards dementia., Nat Commun, Vol: 13

Metformin, a diabetes drug with anti-aging cellular responses, has complex actions that may alter dementia onset. Mixed results are emerging from prior observational studies. To address this complexity, we deploy a causal inference approach accounting for the competing risk of death in emulated clinical trials using two distinct electronic health record systems. In intention-to-treat analyses, metformin use associates with lower hazard of all-cause mortality and lower cause-specific hazard of dementia onset, after accounting for prolonged survival, relative to sulfonylureas. In parallel systems pharmacology studies, the expression of two AD-related proteins, APOE and SPP1, was suppressed by pharmacologic concentrations of metformin in differentiated human neural cells, relative to a sulfonylurea. Together, our findings suggest that metformin might reduce the risk of dementia in diabetes patients through mechanisms beyond glycemic control, and that SPP1 is a candidate biomarker for metformin's action in the brain.

Journal article

Dib M-J, Ahmadi KR, Zagkos L, Gill D, Morris B, Elliott P, Dehghan A, Tzoulaki Iet al., 2022, Associations of genetically predicted vitamin B12 status across the pohenome, Nutrients, Vol: 14, ISSN: 2072-6643

Variation in vitamin B12 levels has been associated with a range of diseases across the life-course, the causal nature of which remains elusive. We aimed to interrogate genetically predicted vitamin B12 status in relation to a plethora of clinical outcomes available in the UK Biobank. Genome-wide association study (GWAS) summary data obtained from a Danish and Icelandic cohort of 45,576 individuals were used to identify 8 genetic variants associated with vitamin B12 levels, serving as genetic instruments for vitamin B12 status in subsequent analyses. We conducted a Mendelian randomisation (MR)-phenome-wide association study (PheWAS) of vitamin B12 status with 945 distinct phenotypes in 439,738 individuals from the UK Biobank using these 8 genetic instruments to proxy alterations in vitamin B12 status. We used external GWAS summary statistics for replication of significant findings. Correction for multiple testing was taken into consideration using a 5% false discovery rate (FDR) threshold. MR analysis identified an association between higher genetically predicted vitamin B12 status and lower risk of vitamin B deficiency (including all B vitamin deficiencies), serving as a positive control outcome. We further identified associations between higher genetically predicted vitamin B12 status and a reduced risk of megaloblastic anaemia (OR = 0.35, 95% CI: 0.20–0.50) and pernicious anaemia (0.29, 0.19–0.45), which was supported in replication analyses. Our study highlights that higher genetically predicted vitamin B12 status is potentially protective of risk of vitamin B12 deficiency associated with pernicious anaemia diagnosis, and reduces risk of megaloblastic anaemia. The potential use of genetically predicted vitamin B12 status in disease diagnosis, progression and management remains to be investigated.

Journal article

Koskeridis F, Evangelou E, Said S, Boyle J, Elliott P, Dehghan A, Tzoulaki Iet al., 2022, Pleiotropic genetic architecture and novel loci for C-reactive protein levels, Nature Communications, Vol: 13, ISSN: 2041-1723

C-reactive protein is involved in a plethora of pathophysiological conditions. Many genetic loci associated with C-reactive protein are annotated to lipid and glucose metabolism genes supporting common biological pathways between inflammation and metabolic traits. To identify novel pleiotropic loci, we perform multi-trait analysis of genome-wide association studies on C-reactive protein levels along with cardiometabolic traits, followed by a series of in silico analyses including colocalization, phenome-wide association studies and Mendelian randomization. We find 41 novel loci and 19 gene sets associated with C-reactive protein with various pleiotropic effects. Additionally, 41 variants colocalize between C-reactive protein and cardiometabolic risk factors and 12 of them display unexpected discordant effects between the shared traits which are translated into discordant associations with clinical outcomes in subsequent phenome-wide association studies. Our findings provide insights into shared mechanisms underlying inflammation and lipid metabolism, representing potential preventive and therapeutic targets.

Journal article

Gaziano L, Sun L, Arnold M, Bell S, Cho K, Kaptoge SK, Song RJ, Burgess S, Posner DC, Mosconi K, Robinson-Cohen C, Mason A, Bolton TR, Tao R, Allara E, Schubert P, Chen L, Staley JR, Staplin N, Altay S, Amiano P, Arndt V, Ärnlöv J, Barr ELM, Björkelund C, Boer JMA, Brenner H, Casiglia E, Chiodini P, Cooper JA, Coresh J, Cushman M, Dankner R, Davidson KW, de Jongh RT, Donfrancesco C, Engström G, Freisling H, de la Cámara AG, Gudnason V, Hankey GJ, Hansson P-O, Heath AK, Hoorn EJ, Imano H, Jassal SK, Kaaks R, Katzke V, Kauhanen J, Kiechl S, Koenig W, Kronmal RA, Kyrø C, Lawlor DA, Ljungberg B, MacDonald C, Masala G, Meisinger C, Melander O, Moreno Iribas C, Ninomiya T, Nitsch D, Nordestgaard BG, Onland-Moret C, Palmieri L, Petrova D, Garcia JRQ, Rosengren A, Sacerdote C, Sakurai M, Santiuste C, Schulze MB, Sieri S, Sundström J, Tikhonoff V, Tjønneland A, Tong T, Tumino R, Tzoulaki I, van der Schouw YT, Monique Verschuren WM, Völzke H, Wallace RB, Goya Wannamethee S, Weiderpass E, Willeit P, Woodward M, Yamagishi K, Zamora-Ros R, Akwo EA, Pyarajan S, Gagnon DR, Tsao PS, Muralidhar S, Edwards TL, Damrauer SM, Joseph J, Pennells L, Wilson PWF, Harrison S, Gaziano TA, Inouye M, Million Veteran Program, Baigent C, Casas JP, Langenberg C, Wareham N, Riboli E, Michael Gaziano J, Danesh J, Hung AM, Butterworth AS, Wood AM, Di Angelantonio E, Emerging Risk Factors CollaborationEPIC-CVDMillion Veteran Programet al., 2022, Mild-to-moderate kidney dysfunction and cardiovascular disease: observational and mendelian randomization analyses., Circulation, Vol: 146, Pages: 1-11, ISSN: 0009-7322

BACKGROUND: End-stage renal disease is associated with a high risk of cardiovascular events. It is unknown, however, whether mild-to-moderate kidney dysfunction is causally related to coronary heart disease (CHD) and stroke. METHODS: Observational analyses were conducted using individual-level data from 4 population data sources (Emerging Risk Factors Collaboration, EPIC-CVD [European Prospective Investigation into Cancer and Nutrition-Cardiovascular Disease Study], Million Veteran Program, and UK Biobank), comprising 648 135 participants with no history of cardiovascular disease or diabetes at baseline, yielding 42 858 and 15 693 incident CHD and stroke events, respectively, during 6.8 million person-years of follow-up. Using a genetic risk score of 218 variants for estimated glomerular filtration rate (eGFR), we conducted Mendelian randomization analyses involving 413 718 participants (25 917 CHD and 8622 strokes) in EPIC-CVD, Million Veteran Program, and UK Biobank. RESULTS: There were U-shaped observational associations of creatinine-based eGFR with CHD and stroke, with higher risk in participants with eGFR values <60 or >105 mL·min-1·1.73 m-2, compared with those with eGFR between 60 and 105 mL·min-1·1.73 m-2. Mendelian randomization analyses for CHD showed an association among participants with eGFR <60 mL·min-1·1.73 m-2, with a 14% (95% CI, 3%-27%) higher CHD risk per 5 mL·min-1·1.73 m-2 lower genetically predicted eGFR, but not for those with eGFR >105 mL·min-1·1.73 m-2. Results were not materially different after adjustment for factors associated with the eGFR genetic risk score, such as lipoprotein(a), triglycerides, hemoglobin A1c, and blood pressure. Mendelian randomization results for stroke were nonsignificant but broadly similar to those for CHD. CONCLUSIONS: In people without manifest cardiovascular disease or diabetes, mild-to-moderat

Journal article

Dehghan A, Pinto RC, Karaman I, Huang J, Durainayagam BR, Ghanbari M, Nazeer A, Zhong Q, Liggi S, Whiley L, Mustafa R, Kivipelto M, Solomon A, Ngandu T, Kanekiyo T, Aikawa T, Radulescu CI, Barnes SJ, Graça G, Chekmeneva E, Camuzeaux S, Lewis MR, Kaluarachchi MR, Ikram MA, Holmes E, Tzoulaki I, Matthews PM, Griffin JL, Elliott Pet al., 2022, Metabolome-wide association study on ABCA7 indicates a role of ceramide metabolism in Alzheimer's disease., Proceedings of the National Academy of Sciences of USA, Vol: 119, Pages: 1-12, ISSN: 0027-8424

Genome-wide association studies (GWASs) have identified genetic loci associated with the risk of Alzheimer's disease (AD), but the molecular mechanisms by which they confer risk are largely unknown. We conducted a metabolome-wide association study (MWAS) of AD-associated loci from GWASs using untargeted metabolic profiling (metabolomics) by ultraperformance liquid chromatography-mass spectrometry (UPLC-MS). We identified an association of lactosylceramides (LacCer) with AD-related single-nucleotide polymorphisms (SNPs) in ABCA7 (P = 5.0 × 10-5 to 1.3 × 10-44). We showed that plasma LacCer concentrations are associated with cognitive performance and genetically modified levels of LacCer are associated with AD risk. We then showed that concentrations of sphingomyelins, ceramides, and hexosylceramides were altered in brain tissue from Abca7 knockout mice, compared with wild type (WT) (P = 0.049-1.4 × 10-5), but not in a mouse model of amyloidosis. Furthermore, activation of microglia increases intracellular concentrations of hexosylceramides in part through induction in the expression of sphingosine kinase, an enzyme with a high control coefficient for sphingolipid and ceramide synthesis. Our work suggests that the risk for AD arising from functional variations in ABCA7 is mediated at least in part through ceramides. Modulation of their metabolism or downstream signaling may offer new therapeutic opportunities for AD.

Journal article

Chalitsios CV, Tsilidis KK, Tzoulaki I, 2022, Psoriasis and COVID-19: A bidirectional Mendelian randomization study., Journal of the American Academy of Dermatology, ISSN: 0190-9622

Journal article

Ryan DK, Karhunen V, Su B, Traylor M, Richardson TG, Burgess S, Tzoulaki I, Gill Det al., 2022, Genetic evidence for protective effects of angiotensin converting enzyme against Alzheimer's disease but not other neurodegenerative diseases in European populations, Neurology Genetics, Vol: 8, ISSN: 2376-7839

Background and Objectives: Angiotensin-converting enzyme (ACE) inhibitors are a commonly prescribed class of medication used to treat heart failure, hypertension, and chronic kidney disease. However, previous observational studies have shown conflicting directions of associations between ACE inhibitors and risk of Alzheimer disease. Genetic evidence has supported a protective effect of cerebral ACE against Alzheimer disease (AD). However, it is unclear whether this effect is mediated through blood pressure and extends to other neurodegenerative diseases.Methods: We performed genetic colocalization investigating an effect of cortical ACE expression on AD risk in people of European ancestry. We further investigated whether any effect of ACE expression on AD risk is mediated through changes in blood pressure and whether effects extend to Parkinson disease, small-vessel disease, or cognitive function in a Mendelian randomization paradigm.Results: There was genetic evidence supporting a protective effect of cortical ACE expression on AD risk in people of European ancestry. Although higher cortical ACE expression was associated with higher blood pressure, there was no strong evidence to support that its association with AD was mediated through blood pressure nor that ACE expression affected risk of other neurodegenerative traits.Discussion: Genetic evidence supports protective effects of cerebral ACE expression on AD, but not other neurodegenerative outcomes in people of European ancestry. Further work is required to investigate whether therapeutic inhibition of ACE increases risk of Alzheimer disease.

Journal article

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