Publications

Genome-wide association studies have identified numerous loci linked with complex diseases, for which the molecular mechanisms remain largely unclear. Comprehensive molecular profiling of circulating metabolites captures highly heritable traits, which can help to uncover metabolic pathophysiology underlying established disease variants. We conduct an extended genome-wide association study of genetic influences on 123 circulating metabolic traits quantified by nuclear magnetic resonance metabolomics from up to 24,925 individuals and identify eight novel loci for amino acids, pyruvate and fatty acids. The LPA locus link with cardiovascular risk exemplifies how detailed metabolic profiling may inform underlying aetiology via extensive associations with very-low-density lipoprotein and triglyceride metabolism. Genetic fine mapping and Mendelian randomization uncover wide-spread causal effects of lipoprotein(a) on overall lipoprotein metabolism and we assess potential pleiotropic consequences of genetically elevated lipoprotein(a) on diverse morbidities via electronic health-care records. Our findings strengthen the argument for safe LPA-targeted intervention to reduce cardiovascular risk.

Background: The relationship between changes in dairy product consumption and risk of type 2 diabetes (T2D) has not been evaluated. Objective: We evaluated the association of 4-year changes in dairy product consumption with subsequent 4-year risk of T2D among U.S. men and women. Methods: We followed-up 35,148 men in the Health Professionals Follow-up Study (1986-2012), 78,357 women in the Nurses’ Health Study (1986-2012), and 82,937 women in the Nurses’ Health Study II (1991-2013). Diet was assessed using validated food frequency questionnaires every 4 years. Cox proportional regression models were used to calculate hazard ratios (HRs) for T2D associated with 4-year changes in dairy product consumption, with adjustment for initial dairy intake and multiple T2D risk factors including BMI and diet quality. Results of the 3 cohorts were pooled using an inverse variance-weighted, fixed-effect meta-analysis. Results: During 2,849,389 person-years of follow-up, we documented 12,007 incident T2D cases. Changes in milk consumption during a 4-year period were not associated with T2D risk in the following 4 years. Increasing yogurt consumption by >0.5 serving/day was associated with a 13% (95% CI: 6%, 19%) lower risk of T2D compared with maintaining a stable consumption. Increasing cheese consumption by >0.5 serving/day was associated with an 8% (95% CI: 2%, 16%) higher risk of T2D. Substituting reduced-fat milk for whole milk or low-fat cheese for high-fat cheese was not associated with subsequent T2D risk. However, increasing intake of yogurt or reduced-fat milk by 1 serving/day and concomitantly decreasing cheese intake by 1 serving/day was associated with a 16% (95% CI: 10%, 22%) and 11% (95% CI: 7%, 15%) lower risk of T2D, respectively. Conclusion: Increasing yogurt consumption was associated with a moderately lower risk of T2D, while increasing cheese consumption was associated with a moderately higher risk. Substituting yogurt or reduced-fat milk for cheese was associated with lower risk of T2D. Disclosure J. Drouin-Chartier: Other Relationship; Self; Dairy Farmers of Canada. Y. Li: None. A.V. Ardisson Korat: None. M. Ding: None. B. Lamarche: Advisory Panel; Self; Dairy Farmers of Canada. J.E. Manson: None. E. Rimm: Advisory Panel; Self; Take C/O, US Highbush Blueberry Council/USDA. W.C. Willett: None. F. Hu: None. Funding National Institutes of Health (UM1CA186107, UM1CA176726, UM1CA167552, DK112940, HL60712, HL118264); Canadian Institutes of Health Research (BPF-156628)

Pregnancy triggers well-known alterations in maternal glucose and lipid balance but its overall effects on systemic metabolism remain incompletely understood. Detailed molecular profiles (87 metabolic measures and 37 cytokines) were measured for up to 4260 women (24–49 years, 322 pregnant) from three population-based cohorts in Finland. Circulating molecular concentrations in pregnant women were compared to those in non-pregnant women. Metabolic profiles were also reassessed for 583 women 6 years later to uncover the longitudinal metabolic changes in response to change in the pregnancy status. Compared to non-pregnant women, all lipoprotein subclasses and lipids were markedly increased in pregnant women. The most pronounced differences were observed for the intermediate-density, low-density and high-density lipoprotein triglyceride concentrations. Large differences were also seen for many fatty acids and amino acids. Pregnant women also had higher concentrations of low-grade inflammatory marker glycoprotein acetyls, higher concentrations of interleukin-18 and lower concentrations of interleukin-12p70. The changes in metabolic concentrations for women who were not pregnant at baseline but pregnant 6 years later (or vice versa) matched (or were mirror-images of) the cross-sectional association pattern. Cross-sectional results were consistent across the three cohorts and similar longitudinal changes were seen for 653 women in 4-year and 497 women in 10-year follow-up. For multiple metabolic measures, the changes increased in magnitude across the three trimesters. Pregnancy initiates substantial metabolic and inflammatory changes in the mothers. Comprehensive characterisation of normal pregnancy is important for gaining understanding of the key nutrients for fetal growth and development. These findings also provide a valuable molecular reference in relation to studies of adverse pregnancy outcomes.

<h3>Background and aims</h3> Preterm birth with very low birth weight. <h3>Methods</h3> We studied the association of preterm birth with 24-hour ambulatory BP and variabilityof BP in 42 young adults (mean age 23.2y) born early preterm (=37 weeks) in Northern Finland population. Wake and sleep period were distinguished with accelerometry in 72.4% of subjects, and for others by time (awake 9 am-11 pm, sleep 01 am-07 am). <h3>Results</h3> Adults born early preterm had 5.6 mmHg (95% CI 1.9–9.3) higher 24-hour SBP, 2.9 mmHg (0.4–5.4) higher 24-hour DBP, 6.4 mmHg (2.8–10.1) higher awake SBP and 4.0 mmHg (0.4–7.5) higher sleep DBP when adjusted for age, sex and use of an accelerometer. Adults born early preterm had also higher within-subject standard deviation (SD) of 24-hour SBP and DBP, awake SBP and DBP and sleep DBP (Figure). Also adults born late preterm had higher SD of 24-hour DBP and sleep SBP and DBP when adjusted for age, sex and use of an accelometer. When adjusted for maternal BMI, smoking during pregnancy and hypertensive pregnancy disorder, parental education, subject’s height and BMI, physical activity and smoking, the results were somewhat attenuated. <h3>Conclusions</h3> Higher 24-hour ambulatory blood pressure and variability of BP may indicate that adults born early preterm are in greater risk for later cardiovascular outcomes.

<b>Background:</b> Living in a farm during early life seems to protect from development of allergic diseases during childhood. However, it remains unclear if the farm environment during early life protects from development of allergic diseases also during adulthood. <b>Methods:</b> In Northern Finland Birth Cohort study subjects born in the northern Finland in 1966 were followed up at the age of 46. Current analyses are based on subjects with information about doctor diagnosed asthma (N=6684) and allergic rhinitis (N=6182) at the age of 46. Prenatal exposure to the farm environment was documented before or at birth. Information on health and sosioeconomic status was collected at the age of 31 and 46 and information on current farm environment at the age of 46. <b>Results:</b> Being born to a family having farm animals decreased the risk of doctor-diagnosed (DD) asthma ever at the age of 46 (adjusted odds ratio [aOR] 0.80, 95% confidence interval [CI] 0.66-0.97), DD allergic rhinitis ever at the age of 46 (aOR 0.72 95% CI 0.62-0.84) and the development of new DD allergic rhinitis between the age of 31 and 46 years (aOR 0.78 95% CI 0.61-1.00). Number of animal species in farm and home environment during early childhood was inversely and dose-dependently associated with the risk of development of new allergic rhinitis between the age of 31 and 46 years. Farm environment during infancy had no effect on the development of new asthma between the age of 31 and 46. <b>Conclusions:</b> This prospective birth cohort study shows, that farm environment during early life may protect from allergic rhinitis, but not from asthma, throughout the life.

Maternal pre-pregnancy overweight/obesity and gestational diabetes (GDM) are associated with increased fat deposition in adult offspring. The purpose of this study was to identify if maternal pre-pregnancy overweight (body mass index (BMI) ≥ 25 kg/m2) or GDM are associated with dietary quality or intake in adult offspring. Participants (n = 882) from two longitudinal cohort studies (ESTER Maternal Pregnancy Disorders Study and the Arvo Ylppo Longitudinal Study) completed a validated food-frequency questionnaire at a mean age of 24.2 years (SD 1.3). Diet quality was evaluated by a Recommended Finnish Diet Index (RDI). The study sample included offspring of normoglycaemic mothers with pre-pregnancy overweight/obesity (ONO = 155), offspring of mothers with GDM regardless of BMI (OGDM = 190) and offspring of mothers with normal weight and no GDM (controls; n = 537). Among men, daily energy and macronutrient intakes were similar in ONO and controls. However, after adjusting for current offspring characteristics, including BMI, daily carbohydrate intake relative to total energy intake was higher in ONO-men [2.2 percentages of total energy intake (95% confidence interval 0.4, 4.0)]. In ONO-women, macronutrient intakes relative to total energy intake were similar with controls, while total daily energy intake seemed lower [−587.2 kJ/day (−1192.0, 4.4)]. After adjusting for confounders, this difference was attenuated. Adherence to a healthy diet, as measured by RDI, was similar in ONO and controls [mean difference: men 0.40 (−0.38, 1.18); women 0.25 (−0.50, 1.00)]. In OGDM vs. controls, total energy and macronutrient intakes were similar for both men and women. Also adherence to a healthy diet was similar [RDI: men 0.09 (−0.62, 0.80); women −0.17 (−0.93, 0.59)]. Our study suggested higher daily carbohydrate intake in male offspring exposed to maternal pre-pregnancy overweight/obesity, compared with controls. Prenatal exposure to GDM was not associated with adult offspring dietary intakes.

The limited ability of common variants to account for the genetic contribution to complex disease has prompted searches for rare variants of large effect, to partly explain the 'missing heritability'. Analyses of genome-wide genotyping data have identified genomic structural variants (GSVs) as a source of such rare causal variants. Recent studies have reported multiple GSV loci associated with risk of obesity. We attempted to replicate these associations by similar analysis of two familial-obesity case-control cohorts and a population cohort, and detected GSVs at 11 out of 18 loci, at frequencies similar to those previously reported. Based on their reported frequencies and effect sizes (OR≥25), we had sufficient statistical power to detect the large majority (80%) of genuine associations at these loci. However, only one obesity association was replicated. Deletion of a 220 kb region on chromosome 16p11.2 has a carrier population frequency of 2×10−4 (95% confidence interval [9.6×10−5–3.1×10−4]); accounts overall for 0.5% [0.19%–0.82%] of severe childhood obesity cases (P = 3.8×10−10; odds ratio = 25.0 [9.9–60.6]); and results in a mean body mass index (BMI) increase of 5.8 kg.m−2 [1.8–10.3] in adults from the general population. We also attempted replication using BMI as a quantitative trait in our population cohort; associations with BMI at or near nominal significance were detected at two further loci near KIF2B and within FOXP2, but these did not survive correction for multiple testing. These findings emphasise several issues of importance when conducting rare GSV association, including the need for careful cohort selection and replication strategy, accurate GSV identification, and appropriate correction for multiple testing and/or control of false discovery rate. Moreover, they highlight the potential difficulty in replicating rare CNV associations across different populations. Nevertheless, we show that such studies are potentially valuable for the identification of variants making an appreciable contribution to complex disease.

Here, with the example of common copy number variation (CNV) in the TSPAN8 gene, we present an important piece of work in the field of CNV detection, that is, CNV association with complex human traits such as 1H NMR metabolomic phenotypes and an example of functional characterization of CNVs among human induced pluripotent stem cells (HipSci). We report TSPAN8 exon 11 (ENSE00003720745) as a pleiotropic locus associated with metabolomic regulation and show that its biology is associated with several metabolic diseases such as type 2 diabetes (T2D) and cancer. Our results further demonstrate the power of multivariate association models over univariate methods and define metabolomic signatures for variants in TSPAN8.

This paper describes the use of electrospray ionization-mass spectrometry (ESI-MS) to screen two libraries of soluble compounds to search for tight binding inhibitors for carbonic anhydrase II (EC 4.2.1.1). The two libraries, H2NO2SC6H4C(O)NH-AA1-AA2-C(O)NHCH2CH2CO2H (1), where AA1 and AA2 are l-amino acids (library size: 289 compounds) or d-amino acids (256 compounds), were constructed by attaching tripeptides to the carboxyl group of 4-carboxybenzenesulfonamide. Screening of both libraries yielded, as the tightest binding inhibitor, compound 1 (AA1 = AA2 = l-Leu; binding constant Kb = 1.4 × 108 M-1). The ability of ESI-MS to estimate simultaneously the relative binding affinities of a protein to soluble ligands in a library, if general, should be useful in drug development.

Development of miniaturized devices that enable rapid and direct analysis of the specific binding of small molecules to proteins could be of substantial importance to the discovery of and screening for new drug molecules. Here, we report highly sensitive and label-free direct electrical detection of small-molecule inhibitors of ATP binding to Abl by using silicon nanowire field-effect transistor devices. Abl, which is a protein tyrosine kinase whose constitutive activity is responsible for chronic myelogenous leukemia, was covalently linked to the surfaces of silicon nanowires within microfluidic channels to create active electrical devices. Concentration-dependent binding of ATP and concentration-dependent inhibition of ATP binding by the competitive small-molecule antagonist STI-571 (Gleevec) were assessed by monitoring the nanowire conductance. In addition, concentration-dependent inhibition of ATP binding was examined for four additional small molecules, including reported and previously unreported inhibitors. These studies demonstrate that the silicon nanowire devices can readily and rapidly distinguish the affinities of distinct small-molecule inhibitors and, thus, could serve as a technology platform for drug discovery.