Associations of Leukocyte Telomere Length With Aerobic and Muscular Fitness in Young Adults.

Decline in both telomere length and physical fitness over the life course may contribute to increased risk of several chronic diseases. The relationship between telomere length and aerobic and muscular fitness is not well characterized. We examined whether there are cross-sectional associations of mean relative leukocyte telomere length (LTL) with objective measures of aerobic fitness, muscle strength, and muscle endurance, using data on 31-year-old participants of the Northern Finland Birth Cohort 1966 (n = 4,952-5,205, varying by exposure-outcome analysis). Aerobic fitness was assessed by means of heart rate measurement following a standardized submaximal step test; muscular fitness was assessed by means of a maximal isometric handgrip strength test and a test of lower-back trunk muscle endurance. Longer LTL was associated with higher aerobic fitness and better trunk muscle endurance in models including adjustment for age, sex, body mass index, socioeconomic position, diet, smoking, alcohol consumption, physical activity level, and C-reactive protein. In a sex-stratified analysis, LTL was not associated with handgrip strength in either men or women. LTL may relate to aspects of physical fitness in young adulthood, but replication of these findings is required, along with further studies to help assess directions and causality in these associations.

Quantified-Self for Obesity: Physical Activity Behaviour Sensing to Improve Health Outcomes.

Physical activity levels in bariatric patients have not been well documented, despite their importance in maintaining weight loss following surgery. This study investigated the feasibility of tracking physical activity using a smartphone app with minimal user interaction. Thus far, we have obtained good quality data from 255 patients at various points in their weight loss journey. Preliminary analyses indicate little change in physical activity levels following surgery with pre-surgery patients reaching an average of 16 minutes per day and post-surgery patients achieving a daily average of 21 minutes. Further analyses using machine-learning techniques will be conducted to determine whether physical activity is a critical factor in distinguishing between successful and unsuccessful weight loss outcomes and in the resolution of comorbid conditions in patients with similar clinical profiles.

Body composition of the host influences dendritic cell phenotype in patients treated for colorectal cancer.

Dendritic cells (DCs) are antigen-presenting cells that can acquire tumour antigens and initiate cytotoxic T cell reactions. Obesity has been proposed as a cause for tumours escaping immune surveillance, but few studies investigate the impact of other body composition parameters. We examined the relationship of DC phenotype with computer tomography (CT)-defined parameters in patients with colorectal cancer (CRC). DCs were identified within peripheral blood mononuclear cells by flow cytometry as HLA-DR positive and negative for markers of other cell lineages in 21 patients. Analysis of CT scans was used to calculate lumbar skeletal muscle index (LSMI) and mean muscle attenuation (MA). Positive correlation between the LSMI and expression of CD40 in all DCs (r = 0.45; p = 0.04) was demonstrated. The MA was positively correlated with scavenger receptor CD36 [all DCs (r = 0.60; p = 0.01) and myeloid DCs (r = 0.63; p < 0.01)]. However, the MA was negatively correlated with CCR7 expression in all DCs (r = -0.46, p = 0.03.) and with CD83 [all DCs (r = -0.63; p = 0.01) and myeloid DCs (r = -0.75; p < 0.01)]. There were no relationships between the fat indexes and the DC phenotype. These results highlight a direct relationship between muscle depletion and changes in stimulatory, migratory and fatty acid-processing potential of DC in patients with CRC.

25-Hydroxyvitamin D Concentration and Leukocyte Telomere Length in Young Adults: Findings From the Northern Finland Birth Cohort 1966.

Higher vitamin D status, lower adiposity, and longer telomere length are each reportedly associated with lower risk of several chronic diseases and all-cause mortality. However, direct relationships between vitamin D status (measured by circulating 25-hydroxyvitamin D (25(OH)D) concentration), adiposity, and telomere length are not well established. We conducted a cross-sectional analysis of associations of 25(OH)D and body mass index (BMI; weight (kg)/height (m)(2)) with mean relative leukocyte telomere length (LTL) using data gathered on 5,096 participants from Northern Finland Birth Cohort 1966 at age 31 years (1997). 25(OH)D was not associated with LTL in either basic or confounder/mediator-adjusted models. BMI was inversely associated with LTL after adjustment for potential confounding by age, sex, socioeconomic position, physical activity, diet, smoking, alcohol intake, and use of oral contraceptives (per 1-unit increase in BMI, mean difference in LTL = -0.4%, 95% confidence interval: -0.6, -0.2). The BMI-LTL association was also independent of 25(OH)D and was attenuated slightly, but remained, after adjustment for C-reactive protein, a marker of low-grade inflammation (mean difference in LTL = -0.3%, 95% confidence interval -0.6, -0.1). These findings suggest that vitamin D status is unlikely to be an important determinant of LTL, at least by young adulthood. Inflammation may partly mediate associations of adiposity with LTL.

The prognostic significance and relationship with body composition of CCR7-positive cells in colorectal cancer.

BACKGROUND AND OBJECTIVES: The host local immune response (LIR) to cancer is a determinant of cancer outcome. Regulation of this local response is largely achieved through chemokine synthesis from the tumor microenvironment such as C-Chemokine-Receptor-7 (CCR7). We examined the LIR measured as CCR7 expression, in colorectal cancers (CRC) and explored relationships with body composition (BC) and survival. METHODS: A study of paraffin-embedded tissue specimens was carried out in 116 patients with non-metastatic CRC. CCR7 expression was determined by immunohistochemistry. Analysis of computer tomography scans was used to calculate BC parameters. Survival analyses and multivariate regression models were used. RESULTS: High CCR7(+) cell density within the tumor stroma and at the margin was significantly associated with increased age, the presence of lymphovascular invasion, higher tumor stage, lymph node metastasis, high Klintrup-Makinen immune score, and myosteatosis. High CCR7(+) cell density in the tumor margin was significantly associated with shorter disease-free (DFS) and overall survival (OS) (P < 0.001). This was also significantly associated with shorter survival in multivariate analysis (HR = 8.87; 95%CI [2.51-31.3]; P < 0.01 for OS and HR = 4.72; 95%CI (1.24-12.9); P = 0.02 for DFS). CONCLUSIONS: Our results suggest that a specific immune microenvironment may be associated with altered host's BC and tumor behavior, and that CCR7 may serve as a novel prognostic biomarker.

Telomere length in circulating leukocytes is associated with lung function and disease.

Several clinical studies suggest the involvement of premature ageing processes in chronic obstructive pulmonary disease (COPD). Using an epidemiological approach, we studied whether accelerated ageing indicated by telomere length, a marker of biological age, is associated with COPD and asthma, and whether intrinsic age-related processes contribute to the interindividual variability of lung function. Our meta-analysis of 14 studies included 934 COPD cases with 15 846 controls defined according to the Global Lungs Initiative (GLI) criteria (or 1189 COPD cases according to the Global Initiative for Chronic Obstructive Lung Disease (GOLD) criteria), 2834 asthma cases with 28 195 controls, and spirometric parameters (forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC) and FEV1/FVC) of 12 595 individuals. Associations with telomere length were tested by linear regression, adjusting for age, sex and smoking status. We observed negative associations between telomere length and asthma (ß= -0.0452, p=0.024) as well as COPD (ß= -0.0982, p=0.001), with associations being stronger and more significant when using GLI criteria than those of GOLD. In both diseases, effects were stronger in females than males. The investigation of spirometric indices showed positive associations between telomere length and FEV1 (p=1.07×10(-7)), FVC (p=2.07×10(-5)), and FEV1/FVC (p=5.27×10(-3)). The effect was somewhat weaker in apparently healthy subjects than in COPD or asthma patients. Our results provide indirect evidence for the hypothesis that cellular senescence may contribute to the pathogenesis of COPD and asthma, and that lung function may reflect biological ageing primarily due to intrinsic processes, which are likely to be aggravated in lung diseases.

Gene-targeted analysis of copy number variants identifies 3 novel associations with coronary heart disease traits.

BACKGROUND: Copy number variants (CNVs) are a major form of genomic variation, which may be implicated in complex disease phenotypes. However, investigation of the role of CNVs in coronary heart disease (CHD) traits has been limited. METHODS AND RESULTS: We examined the use of the cnvHap algorithm for CNV detection, using data for 2500 men from the Second Northwick Park Heart Study (NPHS-II). An Illumina custom chip, including 722 single-nucleotide polymorphisms covering 76 coronary heart disease-trait genes, was used. Common CNVs were significantly associated (at P<0.05, after correction) with coronary heart disease phenotypes in 5 genes. Novel associations of CNVs in toll-like receptor-4 with apolipoprotein AI were replicated (P<0.05) in the Whitehall II cohort (4887 subjects), whereas newly described associations of CNVs in sterol regulatory element-binding protein with apolipoprotein AI and associations of interleukin-6 signal transducer with apolipoprotein B were replicated in the data from 3546 subjects from the North Finnish Birth Cohort 1966 (P<0.05). CONCLUSIONS: This study supports the use of CNV detection algorithms such as cnvHap as potential tools for the identification of novel CNVs, some of which show significant association and replication with coronary heart disease risk phenotypes. However, the functional basis for these associations requires further substantiation.

Effect of vertical sleeve gastrectomy in melanocortin receptor 4-deficient rats.

Bariatric surgery is currently the most effective treatment for obesity. Vertical sleeve gastrectomy (VSG), a commonly applied bariatric procedure, involves surgically incising most of the volume of the stomach. In humans, partial loss of melanocortin receptor-4 (MC4R) activity is the most common monogenic correlate of obesity regardless of lifestyle. At present it is unclear whether genetic alteration of MC4R signaling modulates the beneficial effects of VSG. Following VSG, we analyzed body weight, food intake, glucose sensitivity, and macronutrient preference of wild-type and MC4R-deficient (Mc4r(+/-) and Mc4r(-/-)) rats compared with sham-operated controls. VSG reduced body weight and fat mass and improved glucose metabolism and also shifted preference toward carbohydrates and away from fat. All of this occurred independently of MC4R activity. In addition, MC4R was resequenced in 46 human subjects who underwent VSG. We observed common genetic variations in the coding sequence of MC4R in five subjects. However, none of those variations appeared to affect the outcome of VSG. Taken together, these data suggest that the beneficial effect of VSG on body weight and glucose metabolism is not mediated by alterations in MC4R activity.

Investigation of the HIN200 locus in UK SLE families identifies novel copy number variants.

We undertook a candidate locus study of the HIN200 gene cluster on 1q21-23 in UK systemic lupus erythematosus (SLE) families. To date, despite mounting evidence demonstrating the importance of these proteins in autoimmune disease, cancer, apoptosis, inflammation, and cell cycle arrest, there has been a dearth of data with respect to the genetic characterisation of the HIN200 locus in SLE or any other disease. We typed 83 single nucleotide polymorphisms (SNPs) across 317 kb of the HIN200 cluster in 428 UK SLE families and sought replication from a European-American lupus cohort. We do not find strong evidence of SNP association in either cohort. Interestingly, we do observe a trend for association with certain HIN200 SNPs and serologic subphenotypes in UK SLE that parallels the association of lupus antibodies with the orthologous murine locus. Furthermore, we find the HIN200 locus to be unexpectedly complex in terms of genetic structural organisation. We have identified a number of copy number variants (CNVs) in this region in healthy French males, HapMap samples, and UK SLE families. In summary, candidate interferon signalling genes show evidence of common CNV in human SLE and healthy subjects. The impact of these CNVs in health and disease remains to be determined.

Methylglyoxal modulates immune responses: relevance to diabetes.

Increased methylglyoxal (MG) concentrations and formation of advanced glycation end-products (AGEs) are major pathways of glycaemic damage in diabetes, leading to vascular and neuronal complications. Diabetes patients also suffer increased susceptibility to many common infections, the underlying causes of which remain elusive. We hypothesized that immune glycation damage may account for this increased susceptibility. We previously showed that the reaction mixture (RM) for MG glycation of peptide blocks up regulation of CD83 in myeloid cells and inhibits primary stimulation of T cells. Here, we continue to investigate immune glycation damage, assessing surface and intracellular cytokine protein expression by flow cytometry, T-cell proliferation using a carboxyfluorescein succinimidyl ester assay, and mRNA levels by RT-PCR. We show that the immunomodulatory component of this RM was MG itself, with MG alone causing equivalent block of CD83 and loss of primary stimulation. Block of CD83 expression could be reversed by MG scavenger N-acetyl cysteine. Further, MG within RM inhibited stimulated production of interleukin (IL)-10 protein from myeloid cells plus interferon (IFN)-gamma and tumour necrosis factor (TNF)-alpha from T cells. Loss of IL-10 and IFN-gamma was confirmed by RT-PCR analysis of mRNA, while TNF-alpha message was raised. Loss of TNF-alpha protein was also shown by ELISA of culture supernatants. In addition, MG reduced major histocompatibility complex (MHC) class I expression on the surface of myeloid cells and increased their propensity to apoptose. We conclude that MG is a potent suppressor of myeloid and T-cell immune function and may be a major player in diabetes-associated susceptibility to infection.

A deletion of the HBII-85 class of small nucleolar RNAs (snoRNAs) is associated with hyperphagia, obesity and hypogonadism.

Genetic studies in patients with severe early-onset obesity have provided insights into the molecular and physiological pathways that regulate body weight in humans. We report a 19-year-old male with hyperphagia and severe obesity, mild learning difficulties and hypogonadism, in whom diagnostic tests for Prader-Willi syndrome (PWS) had been negative. We carried out detailed clinical and metabolic phenotyping of this patient and investigated the genetic basis of this obesity syndrome using Agilent 185 k array comparative genomic hybridization (aCGH) and Affymetrix 6.0 genotyping arrays. The identified deletion was validated using multiplex ligation-dependent probe amplification and long-range PCR, followed by breakpoint sequencing which enabled precise localization of the deletion. We identified a approximately 187 kb microdeletion at chromosome 15q11-13 that encompasses non-coding small nucleolar RNAs (including HBII-85 snoRNAs) which were not expressed in peripheral lymphocytes from the patient. Characterization of the clinical phenotype revealed increased ad libitum food intake, normal basal metabolic rate when adjusted for fat-free mass, partial hypogonadotropic hypogonadism and growth failure. We have identified a novel deletion on chromosome 15q11-13 in an individual with hyperphagia, obesity, hypogonadism and other features associated with PWS, which is normally caused by deficiency of several paternally expressed imprinted transcripts within chromosome 15q11-13, a region that includes multiple protein-coding genes as well as several non-coding snoRNAs. These findings provide direct evidence for the role of a particular family of non-coding RNAs, the HBII-85 snoRNA cluster, in human energy homeostasis, growth and reproduction.

Copy number variation at 1q21.1 associated with neuroblastoma.

Common copy number variations (CNVs) represent a significant source of genetic diversity, yet their influence on phenotypic variability, including disease susceptibility, remains poorly understood. To address this problem in human cancer, we performed a genome-wide association study of CNVs in the childhood cancer neuroblastoma, a disease in which single nucleotide polymorphism variations are known to influence susceptibility. We first genotyped 846 Caucasian neuroblastoma patients and 803 healthy Caucasian controls at approximately 550,000 single nucleotide polymorphisms, and performed a CNV-based test for association. We then replicated significant observations in two independent sample sets comprised of a total of 595 cases and 3,357 controls. Here we describe the identification of a common CNV at chromosome 1q21.1 associated with neuroblastoma in the discovery set, which was confirmed in both replication sets. This CNV was validated by quantitative polymerase chain reaction, fluorescent in situ hybridization and analysis of matched tumour specimens, and was shown to be heritable in an independent set of 713 cancer-free parent-offspring trios. We identified a previously unknown transcript within the CNV that showed high sequence similarity to several neuroblastoma breakpoint family (NBPF) genes and represents a new member of this gene family (NBPF23). This transcript was preferentially expressed in fetal brain and fetal sympathetic nervous tissues, and the expression level was strictly correlated with CNV state in neuroblastoma cells. These data demonstrate that inherited copy number variation at 1q21.1 is associated with neuroblastoma and implicate a previously unknown neuroblastoma breakpoint family gene in early tumorigenesis of this childhood cancer.

Genome-wide association study for early-onset and morbid adult obesity identifies three new risk loci in European populations.

We analyzed genome-wide association data from 1,380 Europeans with early-onset and morbid adult obesity and 1,416 age-matched normal-weight controls. Thirty-eight markers showing strong association were further evaluated in 14,186 European subjects. In addition to FTO and MC4R, we detected significant association of obesity with three new risk loci in NPC1 (endosomal/lysosomal Niemann-Pick C1 gene, P = 2.9 x 10(-7)), near MAF (encoding the transcription factor c-MAF, P = 3.8 x 10(-13)) and near PTER (phosphotriesterase-related gene, P = 2.1 x 10(-7)).

FCGR3B copy number variation is associated with susceptibility to systemic, but not organ-specific, autoimmunity.

Naturally occurring variation in gene copy number is increasingly recognized as a heritable source of susceptibility to genetically complex diseases. Here we report strong association between FCGR3B copy number and risk of systemic lupus erythematosus (P = 2.7 x 10(-8)), microscopic polyangiitis (P = 2.9 x 10(-4)) and Wegener's granulomatosis in two independent cohorts from the UK (P = 3 x 10(-3)) and France (P = 1.1 x 10(-4)). We did not observe this association in the organ-specific Graves' disease or Addison's disease. Our findings suggest that low FCGR3B copy number, and in particular complete FCGR3B deficiency, has a key role in the development of systemic autoimmunity.

Leptin receptor genotype at Gln223Arg is associated with body composition, BMD, and vertebral fracture in postmenopausal Danish women.

UNLABELLED: Leptin is emerging as a key regulator of bone remodeling. In a population-based study of 1306 postmenopausal Danish women, nonsynonymous LEPR SNPs were associated with risk of adiposity, BMD, and vertebral fracture. Smoking exacerbates this LEPR-associated fracture risk. INTRODUCTION: Nonsynonymous single nucleotide polymorphisms (SNPs) in the human LEPR gene have been associated with adiposity in a number of studies, but there have been no large-scale studies of their implications for BMD and osteoporotic fracture risk in postmenopausal women. MATERIALS AND METHODS: We carried out a population-based study of 1430 women. Three well-known nonsynonymous leptin receptor (LEPR) SNPs (Lys109Arg, Gln223Arg, and Lys656Asn) were genotyped for qualitative and quantitative association analysis. Phenotype characteristics of main interest were DXA measures of body fat and lean tissue mass, BMD, and radiographic vertebral fractures. RESULTS: Gln223Arg associated with risk of vertebral fracture (overall OR = 1.76; OR in smokers = 2.31; p = 0.0004), in addition to BMD of the femoral neck and total hip (p = 0.036 and 0.008, respectively). Heterozygote carriers showed lower BMD at both sites. Gln223Arg was also associated with adiposity (p = 0.001 for total fat mass). For adiposity, the at-risk allele was G (resulting in an arginine at position 223). CONCLUSIONS: Variation in LEPR seemed to contribute to the variation in BMD and fracture risk in Danish postmenopausal women; the heterozygous genotype was associated with increased risk of manifest osteoporosis. Further studies are needed to replicate these data and to clarify the mechanisms involved.

Genetics of obesity and the prediction of risk for health.

Obesity has always existed in human populations, but until very recently was comparatively rare. The availability of abundant, energy-rich processed foods in the last few decades has, however, resulted in a sharp rise in the prevalence of obesity in westernized countries. Although it is the obesogenic environment that has resulted in this major healthcare problem, it is acting by revealing a sub-population with a pre-existing genetic predisposition to excess adiposity. There is substantial evidence for the heritability of obesity, and research in both rare and common forms of obesity has identified genes with significant roles in its aetiology. Application of this understanding to patient care has been slower. Until very recently, the health risks of obesity were thought to be well understood, with a straightforward correlation between increasing obesity and increasing risk of health problems such as type 2 diabetes, coronary heart disease, hypertension, arthritis and cancer. It is becoming clear, however, that the location of fat deposition, variation in the secretion of adipokines and other factors govern whether a particular obese person develops such complications. Prediction of the health risks of obesity for individual patients is not straightforward, but continuing advances in understanding of genetic factors influencing obesity risk and improved diagnostic technologies mean that the future for such prediction is looking increasingly bright.