MiMIR: R-shiny application to infer risk factors and endpoints from Nightingale Health's 1H-NMR metabolomics data.

MOTIVATION: 1H-NMR metabolomics is rapidly becoming a standard resource in large epidemiological studies to acquire metabolic profiles in large numbers of samples in a relatively low-priced and standardized manner. Concomitantly, metabolomics-based models are increasingly developed that capture disease risk or clinical risk factors. These developments raise the need for user-friendly toolbox to inspect new 1H-NMR metabolomics data and project a wide array of previously established risk models. RESULTS: We present MiMIR (Metabolomics-based Models for Imputing Risk), a graphical user interface that provides an intuitive framework for ad hoc statistical analysis of Nightingale Health's 1H-NMR metabolomics data and allows for the projection and calibration of 24 pre-trained metabolomics-based models, without any pre-required programming knowledge. AVAILABILITY AND IMPLEMENTATION: The R-shiny package is available in CRAN or downloadable at https://github.com/DanieleBizzarri/MiMIR, together with an extensive user manual (also available as Supplementary Documents to the article). SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.

Basal cell carcinoma genetic susceptibility increases the rate of skin ageing: a Mendelian randomization study.

BACKGROUND: Onset of basal cell carcinoma (BCC) is connected to skin ageing, but it is unclear whether higher BCC genetic susceptibility drives skin ageing. OBJECTIVES: To investigate whether loci increasing genetic susceptibility to BCC also drive multiple features of skin ageing, independently of confounding factors, using Mendelian randomization. METHODS: A Mendelian randomization study was conducted in older adults from the Leiden Longevity Study (N = 604). A total of 25 BCC loci, selected based on a published genome-wide association study on BCC (P-value < 5 × 10-8 ), were used as genetic instruments for the calculation of a standardized (mean = 0, SD = 1) weighted BCC genetic risk score. Based on facial photographs, we determined perceived age, and skin wrinkling and pigmented spot grading. RESULTS: A higher BCC genetic risk score was associated with a higher perceived age (adjusted for chronological age and sex) of 0.88 years (95% CI: 0.44, 1.31; P-value = 7.1e-5 ), greater wrinkling by 0.14 grades (95% CI: 0.05, 0.23; P-value = 2.3e-3 ), and greater pigmented spots by 0.17 grades (95% CI: 0.08, 0.25; P-value = 1.1e-4 ). These findings were weakened but still present after exclusion of gene variants in MC1R and IRF4 which have potential pleiotropic effects. CONCLUSIONS: Mechanisms influenced by genetic loci increasing susceptibility to BCC also drive skin ageing suggesting shared biology and shared targets for interventions.

Large-scale pharmacogenomic study of sulfonylureas and the QT, JT and QRS intervals: CHARGE Pharmacogenomics Working Group.

Sulfonylureas, a commonly used class of medication used to treat type 2 diabetes, have been associated with an increased risk of cardiovascular disease. Their effects on QT interval duration and related electrocardiographic phenotypes are potential mechanisms for this adverse effect. In 11 ethnically diverse cohorts that included 71 857 European, African-American and Hispanic/Latino ancestry individuals with repeated measures of medication use and electrocardiogram (ECG) measurements, we conducted a pharmacogenomic genome-wide association study of sulfonylurea use and three ECG phenotypes: QT, JT and QRS intervals. In ancestry-specific meta-analyses, eight novel pharmacogenomic loci met the threshold for genome-wide significance (P<5 × 10-8), and a pharmacokinetic variant in CYP2C9 (rs1057910) that has been associated with sulfonylurea-related treatment effects and other adverse drug reactions in previous studies was replicated. Additional research is needed to replicate the novel findings and to understand their biological basis.

Detecting dispersed duplications in high-throughput sequencing data using a database-free approach.

MOTIVATION: Dispersed duplications (DDs) such as transposon element insertions and copy number variations are ubiquitous in the human genome. They have attracted the interest of biologists as well as medical researchers due to their role in both evolution and disease. The efforts of discovering DDs in high-throughput sequencing data are currently dominated by database-oriented approaches that require pre-existing knowledge of the DD elements to be detected. RESULTS: We present DD_DETECTION, a database-free approach to finding DD events in high-throughput sequencing data. DD_DETECTION is able to detect DDs purely from paired-end read alignments. We show in a comparative study that this method is able to compete with database-oriented approaches in recovering validated transposon insertion events. We also experimentally validate the predictions of DD_DETECTION on a human DNA sample, showing that it can find not only duplicated elements present in common databases but also DDs of novel type. AVAILABILITY AND IMPLEMENTATION: The software presented in this article is open source and available from https://bitbucket.org/mkroon/dd_detection.

Neo-cartilage engineered from primary chondrocytes is epigenetically similar to autologous cartilage, in contrast to using mesenchymal stem cells.

OBJECTIVES: To compare the epigenetic landscape of 3D cell models of human primary articular chondrocytes (hPACs) and human bone-marrow derived mesenchymal stem cells (hBMSCs) and their respective autologous articular cartilage. DESIGN: Using Illumina Infinium HumanMethylation450 BeadChip arrays, the DNA methylation landscape of the different cell sources and autologous cartilage was determined. Pathway enrichment was analyzed using DAVID. RESULTS: Principal Component Analysis (PCA) of methylation data revealed separate clustering of hBMSC samples. Between hBMSCs and autologous cartilage 86,881 cytosine-phosphate-guanine dinucleotides (CpGs) (20.2%), comprising 3,034 differentially methylated regions (DMRs; Δß > 0.1; with the same direction of effect), were significantly differentially methylated. In contrast, between hPACs and autologous cartilage only 5,706 CpGs (1.33%) were differentially methylated. Of interest was the finding of the transcriptionally active, hyper-methylation of a Cartilage Intermediate Layer Protein (CILP) annotated DMR (Δß = 0.16) in PAC-cartilage, corresponding to a profound decrease in CILP expression after in vitro culturing of hPACs as compared to autologous cartilage. CONCLUSIONS: In vitro engineered neo-cartilage tissue from primary chondrocytes, hPACs, exhibits a DNA methylation landscape that is almost identical (99% similarity) to autologous cartilage, in contrast to neo-cartilage engineered from bone marrow-derived mesenchymal stem cells (MSCs). Although hBMSCs are widely used for cartilage engineering purposes the effects of these vast differences on cartilage regeneration and long term consequences of implantation, are not known. The use of hBMSCs or hPACs for future cartilage tissue regeneration purposes should therefore be investigated in more depth in future endeavors to better understand the consequences of the differential methylome on neo-cartilage.

Both low circulating insulin-like growth factor-1 and high-density lipoprotein cholesterol are associated with hair loss in middle-aged women.

BACKGROUND: Multiple biomarkers have been associated with hair loss in women, but studies have shown inconsistent results. OBJECTIVES: We investigated the associations between markers of cardiovascular disease risk (e.g. serum lipid levels and hypertension) and ageing [e.g. 25-hydroxyvitamin D and insulin-like growth factor (IGF)] with hair loss in a population of middle-aged women. METHODS: In a random subgroup of 323 middle-aged women (mean age 61·5 years) from the Leiden Longevity Study, hair loss was graded by three assessors using the Sinclair scale; women with a mean score > 1·5 were classified as cases with hair loss. RESULTS: Every 1 SD increase in high-density lipoprotein (HDL) cholesterol was associated with a 0·65-times lower risk [95% confidence interval (CI) 0·46-0·91] of hair loss. For IGF-1 the risk was 0·68 times lower (95% CI 0·48-0·97) per 1 SD increase, independently of the other studied variables. Women with both IGF-1 and HDL cholesterol levels below the medians of the study population had a 3·47-times higher risk (95% CI 1·30-9·25) of having hair loss. CONCLUSIONS: Low HDL cholesterol and IGF-1 were associated with a higher risk of hair loss in women. However, further studies are required to infer causal relationships.

Non-response to (statin) therapy: the importance of distinguishing non-responders from non-adherers in pharmacogenetic studies.

PURPOSE: In pharmacogenetic research, genetic variation in non-responders and high responders is compared with the aim to identify the genetic loci responsible for this variation in response. However, an important question is whether the non-responders are truly biologically non-responsive or actually non-adherent? Therefore, the aim of this study was to describe, within the PROspective Study of Pravastatin in the Elderly at Risk (PROSPER), characteristics of both non-responders and high responders of statin treatment in order to possibly discriminate non-responders from non-adherers. METHODS: Baseline characteristics of non-responders to statin therapy (≤10 % LDL-C reduction) were compared with those of high responders (>40 % LDL-C reduction) through a linear regression analysis. In addition, pharmacogenetic candidate gene analysis was performed to show the effect of excluding non-responders from the analysis. RESULTS: Non-responders to statin therapy were younger (p = 0.001), more often smoked (p < 0.001), had a higher alcohol consumption (p < 0.001), had lower LDL cholesterol levels (p < 0.001), had a lower prevalence of hypertension (p < 0.001), and had lower cognitive function (p = 0.035) compared to subjects who highly responded to pravastatin treatment. Moreover, excluding non-responders from pharmacogenetic studies yielded more robust results, as standard errors decreased. CONCLUSION: Our results suggest that non-responders to statin therapy are more likely to actually be non-adherers, since they have more characteristics that are viewed as indicators of high self-perceived health and low disease awareness, possibly making the subjects less adherent to study medication. We suggest that in pharmacogenetic research, extreme non-responders should be excluded to overcome the problem that non-adherence is investigated instead of non-responsiveness.

Developmental determinants in non-communicable chronic diseases and ageing.

Prenatal and peri-natal events play a fundamental role in health, development of diseases and ageing (Developmental Origins of Health and Disease (DOHaD)). Research on the determinants of active and healthy ageing is a priority to: (i) inform strategies for reducing societal and individual costs of an ageing population and (ii) develop effective novel prevention strategies. It is important to compare the trajectories of respiratory diseases with those of other chronic diseases.

Longitudinal weight differences, gene expression and blood biomarkers in BMI-discordant identical twins.

BACKGROUND: Body mass index (BMI) discordant monozygotic (MZ) twins allow an examination of the causes and consequences of adiposity in a genetically controlled design. Few studies have examined longitudinal BMI discordance in MZ pairs. OBJECTIVES: The aim of this work was to study the development over time of BMI discordance in adolescent and adult MZ twin pairs and to examine lifestyle, metabolic, inflammatory and gene expression differences associated with concurrent and long-term BMI discordance in MZ pairs. SUBJECTS/METHODS: BMI data from 2775 MZ twin pairs, collected in eight longitudinal surveys and a biobank project between 1991 and 2011, were analyzed to characterize longitudinal discordance. Lifestyle characteristics were compared within discordant pairs (ΔBMI⩾3 kg m(-2)) and biomarkers (lipids, glucose, insulin, C-reactive protein, fibrinogen, interleukin (IL)-6, tumor necrosis factor-α and soluble IL-6 receptor and liver enzymes aspartate aminotransferase, alanine aminotransferase and gamma glutamyl transferase) and gene expression were compared in peripheral blood from discordant pairs who participated in the Netherlands Twin Register biobank project. RESULTS: The prevalence of discordance ranged from 3.2% in 1991 (mean age=17, s.d.=2.4) to 17.4% (N=202 pairs) in 2009 (mean age=35, s.d.=15) and was 16.5% (N=174) among pairs participating in the biobank project (mean age=35, s.d.=12). Of the 699 MZ pairs with BMI data from 3 to 5 time points, 17 pairs (2.4%) were long-term discordant (at all available time points; mean follow-up range=6.4 years). Concurrently discordant pairs showed significant differences in self-ratings of which twin eats most (P=2.3 × 10(-13)) but not in leisure time exercise activity (P=0.28) and smoking (P>0.05). Ten out of the 14 biomarkers showed significantly more unfavorable levels in the heavier of twin of the discordant pairs (P-values <0.001); most of these biomarker differences were largest in longitudinally discordant pairs. No significant gene expression differences were identified, although high ranking genes were enriched for Gene Ontology terms highlighting metabolic gene regulation and inflammation pathways. CONCLUSIONS: BMI discordance is uncommon in adolescent identical pairs but increases with higher pair-mean of BMI at older ages, although long-term BMI discordance is rare. In discordant pairs, the heavier twin had a more unfavorable blood biomarker profile than the genetically matched leaner twin, in support of causal effects of obesity.

Lifestyle and youthful looks.

BACKGROUND: Lifestyle has been proven to have a dramatic effect on the risk of age-related diseases. The association of lifestyle and facial ageing has been less well studied. OBJECTIVES: To identify lifestyle factors that associate with perceived facial age in white north European men and women. METHODS: Lifestyle, facial wrinkling and perceived facial age were studied in two cross-sectional studies consisting of 318 Dutch men and 329 women aged 45-75 years who were part of the Leiden Longevity Study, and 162 English women aged 45-75 years who were nonsmokers. RESULTS: In Dutch men, smoking, having skin that went red in the sun, being outside in the sun most of the summer, sunbed use, wearing false teeth and not flossing teeth were all significantly associated (P < 0·05) with a total 9·3-year higher perceived facial age in a multivariate model adjusting for chronological age. In Dutch women, smoking, sunbathing, sunbed use, few remaining teeth and a low body mass index (BMI) were associated with a total 10·9-year higher perceived facial age. In English women, cleaning teeth only once a day, wearing false teeth, irregular skin moisturization and having skin that went red in the sun were associated with a total 9·1-year higher perceived facial age. Smoking and sunbed use were associated more strongly with wrinkling in women than in men. BMI, sun exposure and skincare were associated predominantly with perceived facial age via wrinkling, whereas oral care was associated via other facial features. CONCLUSIONS: Although associative in nature, these results support the notion that lifestyle factors can have long-term beneficial effects on youthful looks.

Drug-gene interactions and the search for missing heritability: a cross-sectional pharmacogenomics study of the QT interval.

Variability in response to drug use is common and heritable, suggesting that genome-wide pharmacogenomics studies may help explain the 'missing heritability' of complex traits. Here, we describe four independent analyses in 33 781 participants of European ancestry from 10 cohorts that were designed to identify genetic variants modifying the effects of drugs on QT interval duration (QT). Each analysis cross-sectionally examined four therapeutic classes: thiazide diuretics (prevalence of use=13.0%), tri/tetracyclic antidepressants (2.6%), sulfonylurea hypoglycemic agents (2.9%) and QT-prolonging drugs as classified by the University of Arizona Center for Education and Research on Therapeutics (4.4%). Drug-gene interactions were estimated using covariable-adjusted linear regression and results were combined with fixed-effects meta-analysis. Although drug-single-nucleotide polymorphism (SNP) interactions were biologically plausible and variables were well-measured, findings from the four cross-sectional meta-analyses were null (Pinteraction>5.0 × 10(-8)). Simulations suggested that additional efforts, including longitudinal modeling to increase statistical power, are likely needed to identify potentially important pharmacogenomic effects.

Knee and hip articular cartilage have distinct epigenomic landscapes: implications for future cartilage regeneration approaches.

OBJECTIVES: To elucidate the functional epigenomic landscape of articular cartilage in osteoarthritis (OA) affected knee and hip joints in relation to gene expression. METHODS: Using Illumina Infinium HumanMethylation450 BeadChip arrays, genome-wide DNA methylation was measured in 31 preserved and lesioned cartilage sample pairs (14 knees and 17 hips) from patients who underwent a total joint replacement due to primary OA. Using previously published genome-wide expression data of 33 pairs of cartilage samples, of which 13 pairs were overlapping with the current methylation dataset, we assessed gene expression differences in differentially methylated regions (DMRs). RESULTS: Principal component analysis of the methylation data revealed distinct clustering of knee and hip samples, irrespective of OA pathophysiology. A total of 6272 CpG dinucleotides were differentially methylated between the two joints, comprising a total of 357 DMRs containing 1817 CpGs and 245 unique genes. Enrichment analysis of genes proximal of the DMRs revealed significant enrichment for developmental pathways and homeobox (HOX) genes. Subsequent transcriptomic analysis of DMR genes exposed distinct knee and hip expression patterns. CONCLUSIONS: Our findings reveal consistent DMRs between knee and hip articular cartilage that marked transcriptomic differences among HOX genes, which were not reflecting the temporal sequential HOX expression pattern during development. This implies distinct mechanisms for maintaining cartilage integrity in adulthood, thereby contributing to our understanding of cartilage homeostasis and future tissue regeneration approaches.

Relationship between the functional exon 3 deleted growth hormone receptor polymorphism and symptomatic osteoarthritis in women.

BACKGROUND: Several studies suggest a role of the growth hormone (GH)/insulin-like growth factor-1 (IGF-1) axis in the pathophysiology of primary osteoarthritis (OA). A common polymorphism of the GH receptor (exon 3 deletion, d3-GHR) is associated with increased GH/IGF-1 activity. OBJECTIVE: To study associations between the d3-GHR polymorphism and symptomatic OA. METHODS: In the GARP (Genetics, osteoARthritis and Progression) study, we compared the d3-GHR polymorphism between OA patients and controls. GARP patients were genotyped for seven single nucleotide polymorphisms encompassing the d3-GHR gene, using rs4590183 as proxy for d3-GHR (pairwise r(2)=1). Binary logistic regression models with robust SEs were performed, stratified by sex. For replication, rs4590183 was tested in three additional cohorts. Fixed- and random-effects combined analyses were performed. RESULTS: In female GARP patients with severe familial OA, d3-GHR was associated with OA (adjusted OR 1.36 (95% CI 1.01 to 1.83), p=0.043), independently of age and body mass index. Combined analysis of all studies showed suggestive evidence for association between d3-GHR and OA (OR=1.17 (95% CI 1.04 to 1.30), p=0.008). Evidence was strongest in hip OA cases, without any evidence for heterogeneity. CONCLUSIONS: In women, the d3-GHR polymorphism was associated with symptomatic OA, especially at the hip site.

Sex-specific effects of naturally occurring variants in the dopamine receptor D2 locus on insulin secretion and type 2 diabetes susceptibility.

AIMS: Modulation of dopamine receptor D2 (DRD2) activity affects insulin secretion in both rodents and isolated pancreatic ß-cells. We hypothesized that single nucleotide polymorphisms in the DRD2/ANKK1 locus may affect susceptibility to type 2 diabetes in humans. METHODS: Four potentially functional variants in the coding region of the DRD2/ANKK1 locus (rs1079597, rs6275, rs6277, rs1800497) were genotyped and analysed for type 2 diabetes susceptibility in up to 25 000 people (8148 with type 2 diabetes and 17687 control subjects) from two large independent Dutch cohorts and one Danish cohort. In addition, 340 Dutch subjects underwent a 2-h hyperglycaemic clamp to investigate insulin secretion. Since sexual dimorphic associations related to DRD2 polymorphisms have been previously reported, we also performed a gender-stratified analysis. RESULTS: rs1800497 at the DRD2/ANKK1 locus was associated with a significantly increased risk for type 2 diabetes in women (odds ratio 1.14 (1.06-1.23); P = 4.1*104) but not in men (odds ratio 1.00 (95% CI 0.93-1.07); P = 0.92) or the combined group. Although rs1800497 was not associated with insulin secretion, we did find another single nucleotide polymorphism in this locus, rs6275, to be associated with increased first-phase glucose-stimulated insulin secretion in women (P = 5.5*104) but again not in men (P = 0.34). CONCLUSION: The present data identify DRD2/ANKK1 as a potential sex-specific type 2 diabetes susceptibility gene.

Association study of candidate genes for the progression of hand osteoarthritis.

OBJECTIVE: Although a few consistent osteoarthritis (OA) susceptibility genes have been identified, little is known on OA progression. Since OA progression is clinically the most relevant phenotype, we investigate the association between asporin (ASPN), bone morphogenetic protein 5 (BMP5) and growth differentiation factor 5 (GDF5) polymorphisms and progression of hand OA. METHODS: Single-nucleotide polymorphisms (SNPs) ASPN rs13301537, BMP5 rs373444 and GDF5 rs143383 were genotyped in 251 hand OA patients from the Genetics osteoARthritis and Progression (GARP) study and 725 controls. In a case-control comparison we assessed the association between these SNPs and radiographic progression of hand OA over 6 years, which was based on change in osteophytes or joint space narrowing (JSN), above the smallest detectable change. SNPs with suggestive evidence for association were further analysed for their effect on progression over 2 years, and for the mean change in osteophytes and JSN. RESULTS: The minor allele of ASPN SNP rs13301537 was associated with hand OA progression over 6 years (odds ratio (OR) (95% CI) 1.49 (1.06-2.07); P = 0.020). The mean change in osteophytes and JSN was higher in carriers of the minor allele compared to homozygous carriers of the common allele with mean difference of 0.73 (95% CI - 0.07-1.56; P = 0.073) and 0.82 (95% CI 0.12-1.52; P = 0.022), respectively. An association with similar effect size was found between ASPN SNP rs13301537 and 2-year progression, and the mean change in osteophytes and JSN was significantly higher in homozygotes. CONCLUSION: ASPN is associated with hand OA progression. This gives insight in the pathogenesis of hand OA progression and identified a potential target for therapeutic approaches.

Serum insulin-like growth factor 1 and facial ageing: high levels associate with reduced skin wrinkling in a cross-sectional study.

BACKGROUND: Insulin-like growth factor (IGF)-1 is a growth factor that can influence fibroblast functioning, with effects including the inhibition of collagenases and the induction of collagen expression. OBJECTIVES: To assess whether serum IGF-1, IGF-binding protein (IGFBP)3 and the ratio between IGF-1 and IGFBP3, as a measure of IGF-1 bioavailability, are associated with facial ageing and skin wrinkling. METHODS: From a random sample comprising 617 subjects from the Leiden Longevity Study, perceived age and skin wrinkling were assessed from facial photographs, and IGF-1 and IGFBP3 were measured in serum. The associations were assessed using linear regression models, adjusted for chronological age, sex, body mass index, smoking and sun exposure. RESULTS: Across tertiles of the ratio of IGF-1 to IGFBP3, and after adjusting for all potential confounding factors, the mean perceived age decreased from 60·6 years in the lowest tertile to 59·5 years in the highest (P = 0·045). Similarly, the mean skin wrinkling grade decreased from 4·8 in the lowest tertile to 4·5 in the highest (P = 0·011). Adding skin wrinkling as a covariate in the analysis between IGF-1 and perceived age diminished this association. CONCLUSIONS: This study demonstrates that a higher ratio of IGF-1 to IGFBP3 associates with a lower perceived age, via its association with reduced skin wrinkling. Whether high IGF-1 levels actually delay the accumulation of skin wrinkling now needs investigating.

A gene variant near ATM is significantly associated with metformin treatment response in type 2 diabetes: a replication and meta-analysis of five cohorts.

AIMS/HYPOTHESIS: In this study we aimed to replicate the previously reported association between the glycaemic response to metformin and the SNP rs11212617 at a locus that includes the ataxia telangiectasia mutated (ATM) gene in multiple additional populations. METHODS: Incident users of metformin selected from the Diabetes Care System West-Friesland (DCS, n = 929) and the Rotterdam Study (n = 182) from the Netherlands, and the CARDS Trial (n = 254) from the UK were genotyped for rs11212617 and tested for an association with both HbA(1c) reduction and treatment success, defined as the ability to reach the treatment target of an HbA(1c) ≤ 7 % (53 mmol/mol). Finally, a meta-analysis including data from literature was performed. RESULTS: In the DCS cohort, we observed an association between rs11212617 genotype and treatment success on metformin (OR 1.27, 95% CI 1.03, 1.58, p = 0.028); in the smaller Rotterdam Study cohort, a numerically similar but non-significant trend was observed (OR 1.45, 95% CI 0.87, 2.39, p = 0.15); while in the CARDS cohort there was no significant association. In meta-analyses of these three cohorts separately or combined with the previously published cohorts, rs11212617 genotype is associated with metformin treatment success (OR 1.24, 95% CI 1.04, 1.49, p = 0.016 and OR 1.25, 95% CI 1.33, 1.38, p = 7.8 × 10(-6), respectively). CONCLUSIONS/INTERPRETATION: A gene variant near ATM is significantly associated with metformin treatment response in type 2 diabetic patients from the Netherlands and the UK. This is the first robustly replicated common susceptibility locus found to be associated with metformin treatment response.

Proton magnetic resonance spectroscopy shows lower intramyocellular lipid accumulation in middle-aged subjects predisposed to familial longevity.

Families predisposed to longevity show enhanced glucose tolerance and skeletal muscle insulin sensitivity compared with controls, independent of body composition and physical activity. Intramyocellular lipid (IMCL) accumulation in skeletal muscle has been associated with insulin resistance. Here, we assessed whether subjects enriched for familial longevity have lower IMCL levels. We determined IMCL levels in 48 subjects from the Leiden Longevity Study, comprising 24 offspring of nonagenarian siblings and 24 partners thereof as control subjects. IMCL levels were assessed noninvasively using short echo time proton magnetic resonance spectroscopy ((1)H-MRS) of the tibialis anterior muscle with a 7 Tesla human MR scanner. IMCL levels were calculated relative to the total creatine (tCr) CH3 signal. Physical activity was assessed using the International Physical Activity Questionnaire (IPAQ). After correction for age, sex, BMI, and physical activity, offspring of long-lived nonagenarian siblings tended to show lower IMCL levels compared with controls (IMCL/tCr: 3.1 ± 0.5 vs. 4.5 ± 0.5, respectively, P = 0.051). In a pairwise comparison, this difference reached statistical significance (P = 0.038). We conclude that offspring of nonagenarian siblings predisposed to longevity show lower IMCL levels compared with environmentally matched control subjects. Future research should focus on assessing what mechanisms may explain the lower IMCL levels in familial longevity.

Glucocorticoid receptor gene polymorphisms are associated with reduced first-phase glucose-stimulated insulin secretion and disposition index in women, but not in men.

AIM: Glucocorticoids are efficacious anti-inflammatory agents, but, in susceptible individuals, these drugs may induce glucose intolerance and diabetes by affecting ß-cell function and insulin sensitivity. We assessed whether polymorphisms in the glucocorticoid receptor gene NR3C1 associate with measures of ß-cell function and insulin sensitivity derived from hyperglycaemic clamps in subjects with normal or impaired glucose tolerance. METHODS: A cross-sectional cohort study was conducted in four academic medical centres in the Netherlands and Germany. Four hundred and forty-nine volunteers (188 men; 261 women) were recruited with normal glucose tolerance (n=261) and impaired glucose tolerance (n=188). From 2-h hyperglycaemic clamps, first- and second-phase glucose-stimulated insulin secretion, as well as insulin sensitivity index and disposition index, were calculated. All participants were genotyped for the functional NR3C1 polymorphisms N363S (rs6195), BclI (rs41423247), ER22/23EK (rs6189/6190), 9ß A/G (rs6198) and ThtIIII (rs10052957). Associations between these polymorphisms and ß-cell function parameters were assessed. RESULTS: In women, but not in men, the N363S polymorphism was associated with reduced disposition index (P=1.06 10(-4) ). Also only in women, the ER22/23EK polymorphism was associated with reduced first-phase glucose-stimulated insulin secretion (P=0.011) and disposition index (P=0.003). The other single-nucleotide polymorphisms were not associated with ß-cell function. Finally, none of the polymorphisms was related to insulin sensitivity. CONCLUSION: The N363S and ER22/23EK polymorphisms of the NR3C1 gene are negatively associated with parameters of ß-cell function in women, but not in men.

Osteoarthritis susceptibility genes influence the association between hip morphology and osteoarthritis.

OBJECTIVE: The identified osteoarthritis (OA) susceptibility genes are mainly active in skeletal development and could thus affect joint geometry. Because nonoptimal joint geometry is a risk factor for the development of OA, we investigated if and how the path that leads from nonoptimal joint geometry to OA of the hip is influenced by these genes. METHODS: The shape of the hips of subjects in the Genetics, Osteoarthritis and Progression Study, consisting of sibling pairs with symptomatic OA at multiple joint locations, was quantified by applying a statistical shape model to radiographs. Shape aspects (modes) were correlated to OA characteristics. We then tested for the association of shape modes with OA susceptibility single-nucleotide polymorphisms (SNPs) of GDF5, FRZB, and DIO2. RESULTS: Four of 23 shape modes (mode 1, mode 17, mode 18, and mode 21) were strongly associated with OA characteristics. We observed a significant interaction between carrier status of DIO2 rs12885300 and hip OA characteristics for mode 1 (P = 0.005). This indicates that this specific aspect of hip shape correlates with OA characteristics only in carriers of the susceptibility allele. CONCLUSION: Our results suggest that it is more likely that the rs12885300 SNP of DIO2 increases the vulnerability of cartilage to nonoptimal bone shapes rather than directly influencing the formation of these shapes.