Insulin resistance in children and adolescents : mechanisms and clinical effects

Background: Insulin resistance is a condition in which insulin does not achieve appropriate response in different target tissues, it is associated with obesity and one of the main culprits in the development of type 2 diabetes. An early sign of disturbed glucose-insulin homeostasis is impaired fasting glucose (IFG) where glucose is elevated in the fasting state. The American Diabetes Association (ADA) and the International Society for Pediatric Diabetes (ISPAD) suggest 5.6 mmol/L as a cut-off level for IFG, the World Health Organization supports 6.1 mmol/L. Impaired glucose tolerance (IGT) is defined as elevated glucose after a 2-hour glucose tolerance test, which also is a sign of disturbed glucose-insulin homeostasis. IFG and/or IGT, collectively prediabetes, is associated with a significantly elevated risk of type 2 diabetes development in adults, but the consequences of the prediabetic condition in children is not as evident. In Sweden the prevalence of type 2 diabetes in youth has been low, in spite of an increasing overweight and obesity, which are major risk factors for type 2 diabetes. However, the exact present prevalence of type 2 diabetes in youth is currently not known. Early-onset of type 2 diabetes is associated with a high morbidity already at young age and seems to be more aggressive compared with early-onset type 1 diabetes. Aim: The aims of this thesis were to investigate the pathogenesis of prediabetes in obese children, to examine the prevalence of prediabetes and type 2 diabetes among severely obese adolescents and to estimate the occurrence of complications related to early-onset type 2 diabetes compared to type 1 diabetes of same duration. Method: Study I and II in this thesis contain data from the Swedish Childhood Obesity Register (BORIS), which is a national quality registry for obesity treatment in childhood and adolescence. Fasting glucose and glucose levels after an oral glucose tolerance test (OGTT) was made to define normal glucose tolerance or prediabetic stage. A frequently sampled intravenous glucose tolerance test was used to study acute insulin response (AIR), insulin sensitivity (Si), and disposition index (DI) in children with obesity. Study III contains data from the National Diabetes Register (NDR); both from the pediatric register (SWEDIABKIDS) and the adult register (NDR) regarding adolescents and young adults with type 1 and 2 diabetes. Study I and II are cross-sectional observational studies and Study III is a longitudinal, retrospective cohort study. Results: Among severely obese children the prevalence of isolated IFGADA was 35.8 %, isolated IGT 6% and a combined IFG and IGT in 14.2 %. Combined IFG/IGT was associated with significantly lower AIR compared with subjects who had normal glucose metabolism (p<0.05) and DI was the major determinant of 2-h OGTT glucose levels (β=−0.49, p=0.0126). Comparing IFGADA and IFGWHO in obese children, only IFGWHO was associated with a lower AIR and DI (p<0.001). In total 1413 adolescents and young adults were diagnosed and registered in NDR with type 2 diabetes between 1994-2014. Early-onset type 2 diabetes had, compared with individuals with type 1 diabetes with equivalent diabetes duration, significantly higher risk of developing microalbuminuria with a hazard ratio (HR) of 3.32 (95% CI 2.86-3.85, P < .001), and also retinopathy with a HR of 1.17 (95% CI 1.06-1.30, P 0.04). These differences occurred despite lower HbA1c levels among individuals with type 2 diabetes in comparison with type 1 diabetes. Conclusion: The prevalence of prediabetes was very high among adolescents with severe obesity. IFGWHO is significantly associated to disturbed glucose metabolism, and IFGADA could be associated with IGT. A combination of IFGADA/ IGT was significantly associated with impaired -cell function. Although both type 1 and 2 diabetes were associated with complications, the prevalence of complications and comorbidities is significantly higher among those with early-onset type 2 diabetes compared with type 1 diabetes. Our results confirm previous studies that type 2 diabetes is a severe disease when young individuals are affected, and an active treatment with a widened focus on cardiometabolic risk factors is required to reduce the risk

Infiltration of CD163-, PD-L1-and FoxP3-positive cells adversely affects outcome in patients with mantle cell lymphoma independent of established risk factors

We characterised patients with mantle cell lymphoma (MCL) with poor prognosis based on differences in immune infiltration. Different expressions of the tumour cell markers Cyclin D1 and sex-determining region Y-box transcription factor 11 (SOX11), and the immune markers cluster of differentiation 3 (CD3), CD4, CD8, CD25, forkhead box protein P3 (FoxP3), T-box transcription factor TBX21 (T-bet), programmed cell death protein 1 (PD-1), programmed-death ligand 1 (PD-L1) and CD163 were investigated for all-cause mortality in 282 patients with MCL and time-to-progression (TTP) in 106 clinical trial patients. With increasing age, a significantly lower infiltration of CD3(+) T lymphocytes was seen. T-cell infiltration was independent of cellular tumour antigen p53 (p53) expression, Ki-67, morphology and frequency of tumour cells. The all-cause mortality was higher in patients with PD-L1-expression above cut-off [hazard ratio (HR) 1 center dot 97, 95% confidence interval (CI) 1 center dot 18-3 center dot 25, adjusted for sex and MCL International Prognostic Index (MIPI)] and a higher frequency of CD163(+) cells (continuously, HR 1 center dot 51, 95% CI 1 center dot 03-2 center dot 23, adjusting for age, sex, morphology, Ki-67 and p53). In patients treated within the Nordic Lymphoma Group MCL2/3 trials, TTP was shorter in patients with a higher frequency of FoxP3(+) cells (HR 3 center dot 22, 95% CI 1 center dot 40-7 center dot 43) and CD163(+) cells (HR 6 center dot 09, 95% CI 1 center dot 84-20 center dot 21), independent of sex and MIPI. When combined a higher frequency of CD163(+) macrophages and PD-L1(+) cells or high CD163(+) macrophages and FoxP3(+) regulatory T cells indicated worse outcome independent of established risk factors. The T-cell infiltrate was in turn independent of molecular characteristics of the malignant cells and decreased with age.Peer reviewe

Microalbuminuria and retinopathy in adolescents and young adults with type 1 and type 2 diabetes.

AIM: To estimate the occurrence of complications related to early-onset type 2 diabetes compared with type 1 diabetes. METHODS: All individuals registered in the Swedish Pediatric Quality Diabetes Register and the Swedish National Diabetes Register with type 2 diabetes diagnosis at 10 to 25?years of age between 1996 and 2014 (n = 1413) were included. As controls, individuals with type 1 diabetes were randomly selected from the same registers and were matched for age, sex, and year-of-onset (n = 3748). RESULTS: Of the adolescents with type 2 diabetes in the pediatric register, 7.7% had microalbuminuria and 24.6% had signs of retinopathy 5?years after diagnosis, whereas the adolescents with type 1 diabetes 3.8% had microalbuminuria and 19.2% had retinopathy. Among the young adults with type 2 diabetes from the adult diabetes register 10?years after diagnosis 15.2% had microalbuminuria and 39.7% retinopathy, whereas the young adults with type 1 diabetes 4.8% had microalbuminuria and 43.8% retinopathy. After adjustment for established risk factors measured over time in the whole combined cohort, individuals with type 2 diabetes had significantly higher risk of microalbuminuria with a hazard ratio (HR) of 3.32 (95% confidence interval, CI 2.86-3.85, P?< .001), and retinopathy with a HR of 1.17 (95% CI 1.06-1.30, P 0.04). CONCLUSIONS: The prevalence of complications and comorbidities was higher among those with type 2 diabetes compared with type 1 diabetes, although prevalent in both groups. Early monitoring and more active treatment of type 2 diabetes in young individuals is required

Adopting a healthy lifestyle when pregnant and obese - an interview study three years after childbirth

Background: Obesity during pregnancy is increasing and is related to life-threatening and ill-health conditions in both mother and child. Initiating and maintaining a healthy lifestyle when pregnant with body mass index (BMI) ≥ 30 kg/m2 can improve health and decrease risks during pregnancy and of long-term illness for the mother and the child. To minimise gestational weight gain women with BMI ≥ 30 kg/m2 in early pregnancy were invited to a lifestyle intervention including advice and support on diet and physical activity in Gothenburg, Sweden. The aim of this study was to explore the experiences of women with BMI ≥ 30 kg/m2 regarding minimising their gestational weight gain, and to assess how health professionals' care approaches are reflected in the women's narratives. Methods: Semi-structured interviews were conducted with 17 women who had participated in a lifestyle intervention for women with BMI ≥ 30 kg/m2 during pregnancy 3 years earlier. The interviews were digitally recorded and transcribed in full. Thematic analysis was used. Results: The meaning of changing lifestyle for minimising weight gain and of the professional's care approaches is described in four themes: the child as the main motivation for making healthy changes; a need to be seen and supported on own terms to establish healthy routines; being able to manage healthy activities and own weight; and need for additional support to maintain a healthy lifestyle. Conclusions: To support women with BMI ≥ 30 kg/m2 to make healthy lifestyle changes and limit weight gain during pregnancy antenatal health care providers should 1) address women's weight in a non-judgmental way using BMI, and provide accurate and appropriate information about the benefits of limited gestational weight gain; 2) support the woman on her own terms in a collaborative relationship with the midwife; 3) work in partnership to give the woman the tools to self-manage healthy activities and 4) give continued personal support and monitoring to maintain healthy eating and regular physical activity habits after childbirth involving also the partner and family

Exploring the genetics of irritable bowel syndrome: A GWA study in the general population and replication in multinational case-control cohorts

OBJECTIVE: IBS shows genetic predisposition, but adequately powered gene-hunting efforts have been scarce so far. We sought to identify true IBS genetic risk factors by means of genome-wide association (GWA) and independent replication studies. DESIGN: We conducted a GWA study (GWAS) of IBS in a general population sample of 11\u2005326 Swedish twins. IBS cases (N=534) and asymptomatic controls (N=4932) were identified based on questionnaire data. Suggestive association signals were followed-up in 3511 individuals from six case-control cohorts. We sought genotype-gene expression correlations through single nucleotide polymorphism (SNP)-expression quantitative trait loci interactions testing, and performed in silico prediction of gene function. We compared candidate gene expression by real-time qPCR in rectal mucosal biopsies of patients with IBS and controls. RESULTS: One locus at 7p22.1, which includes the genes KDELR2 (KDEL endoplasmic reticulum protein retention receptor 2) and GRID2IP (glutamate receptor, ionotropic, delta 2 (Grid2) interacting protein), showed consistent IBS risk effects in the index GWAS and all replication cohorts and reached p=9.31 710(-6) in a meta-analysis of all datasets. Several SNPs in this region are associated with cis effects on KDELR2 expression, and a trend for increased mucosal KDLER2 mRNA expression was observed in IBS cases compared with controls. CONCLUSIONS: Our results demonstrate that general population-based studies combined with analyses of patient cohorts provide good opportunities for gene discovery in IBS. The 7p22.1 and other risk signals detected in this study constitute a good starting platform for hypothesis testing in future functional investigations. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions

Gene set of nuclear-encoded mitochondrial regulators is enriched for common inherited variation in obesity

There are hints of an altered mitochondrial function in obesity. Nuclear-encoded genes are relevant for mitochondrial function (3 gene sets of known relevant pathways: (1) 16 nuclear regulators of mitochondrial genes, (2) 91 genes for oxidative phosphorylation and (3) 966 nuclear-encoded mitochondrial genes). Gene set enrichment analysis (GSEA) showed no association with type 2 diabetes mellitus in these gene sets. Here we performed a GSEA for the same gene sets for obesity. Genome wide association study (GWAS) data from a case-control approach on 453 extremely obese children and adolescents and 435 lean adult controls were used for GSEA. For independent confirmation, we analyzed 705 obesity GWAS trios (extremely obese child and both biological parents) and a population-based GWAS sample (KORA F4, n = 1,743). A meta-analysis was performed on all three samples. In each sample, the distribution of significance levels between the respective gene set and those of all genes was compared using the leading-edge-fraction-comparison test (cut-offs between the 50(th) and 95(th) percentile of the set of all gene-wise corrected p-values) as implemented in the MAGENTA software. In the case-control sample, significant enrichment of associations with obesity was observed above the 50(th) percentile for the set of the 16 nuclear regulators of mitochondrial genes (p(GSEA,50) = 0.0103). This finding was not confirmed in the trios (p(GSEA,50) = 0.5991), but in KORA (p(GSEA,50) = 0.0398). The meta-analysis again indicated a trend for enrichment (p(MAGENTA,50) = 0.1052, p(MAGENTA,75) = 0.0251). The GSEA revealed that weak association signals for obesity might be enriched in the gene set of 16 nuclear regulators of mitochondrial genes

Targeted Analysis of Serum Proteins Encoded at Known Inflammatory Bowel Disease Risk Loci

Few studies have investigated the blood proteome of inflammatory bowel disease (IBD). We characterized the serum abundance of proteins encoded at 163 known IBD risk loci and tested these proteins for their biomarker discovery potential. Based on the Human Protein Atlas (HPA) antibody availability, 218 proteins from genes mapping at 163 IBD risk loci were selected. Targeted serum protein profiles from 49 Crohns disease (CD) patients, 51 ulcerative colitis (UC) patients, and 50 sex- and age-matched healthy individuals were obtained using multiplexed antibody suspension bead array assays. Differences in relative serum abundance levels between disease groups and controls were examined. Replication was attempted for CD-UC comparisons (including disease subtypes) by including 64 additional patients (33 CD and 31 UC). Antibodies targeting a potentially novel risk protein were validated by paired antibodies, Western blot, immuno-capture mass spectrometry, and epitope mapping. By univariate analysis, 13 proteins mostly related to neutrophil, T-cell, and B-cell activation and function were differentially expressed in IBD patients vs healthy controls, 3 in CD patients vs healthy controls and 2 in UC patients vs healthy controls (q <0.01). Multivariate analyses further differentiated disease groups from healthy controls and CD subtypes from UC (P <0.05). Extended characterization of an antibody targeting a novel, discriminative serum marker, the laccase (multicopper oxidoreductase) domain containing 1 (LACC1) protein, provided evidence for antibody on-target specificity. Using affinity proteomics, we identified a set of IBD-associated serum proteins encoded at IBD risk loci. These candidate proteins hold the potential to be exploited as diagnostic biomarkers of IBD.Peer reviewe

Predicting cell types and genetic variations contributing to disease by combining GWAS and epigenetic data

Genome-wide association studies (GWASs) identify single nucleotide polymorphisms (SNPs) that are enriched in individuals suffering from a given disease. Most disease-associated SNPs fall into non-coding regions, so that it is not straightforward to infer phenotype or function; moreover, many SNPs are in tight genetic linkage, so that a SNP identified as associated with a particular disease may not itself be causal, but rather signify the presence of a linked SNP that is functionally relevant to disease pathogenesis. Here, we present an analysis method that takes advantage of the recent rapid accumulation of epigenomics data to address these problems for some SNPs. Using asthma as a prototypic example; we show that non-coding disease-associated SNPs are enriched in genomic regions that function as regulators of transcription, such as enhancers and promoters. Identifying enhancers based on the presence of the histone modification marks such as H3K4me1 in different cell types, we show that the location of enhancers is highly cell-type specific. We use these findings to predict which SNPs are likely to be directly contributing to disease based on their presence in regulatory regions, and in which cell types their effect is expected to be detectable. Moreover, we can also predict which cell types contribute to a disease based on overlap of the disease-associated SNPs with the locations of enhancers present in a given cell type. Finally, we suggest that it will be possible to re-analyze GWAS studies with much higher power by limiting the SNPs considered to those in coding or regulatory regions of cell types relevant to a given disease

Polymorphisms in Genes of Relevance for Oestrogen and Oxytocin Pathways and Risk of Barrett's Oesophagus and Oesophageal Adenocarcinoma: A Pooled Analysis from the BEACON Consortium.

BACKGROUND: The strong male predominance in oesophageal adenocarcinoma (OAC) and Barrett's oesophagus (BO) continues to puzzle. Hormonal influence, e.g. oestrogen or oxytocin, might contribute. METHODS: This genetic-epidemiological study pooled 14 studies from three continents, Australia, Europe, and North America. Polymorphisms in 3 key genes coding for the oestrogen pathway (receptor alpha (ESR1), receptor beta (ESR2), and aromatase (CYP19A1)), and 3 key genes of the oxytocin pathway (the oxytocin receptor (OXTR), oxytocin protein (OXT), and cyclic ADP ribose hydrolase glycoprotein (CD38)), were analysed using a gene-based approach, versatile gene-based test association study (VEGAS). RESULTS: Among 1508 OAC patients, 2383 BO patients, and 2170 controls, genetic variants within ESR1 were associated with BO in males (p = 0.0058) and an increased risk of OAC and BO combined in males (p = 0.0023). Genetic variants within OXTR were associated with an increased risk of BO in both sexes combined (p = 0.0035) and in males (p = 0.0012). We followed up these suggestive findings in a further smaller data set, but found no replication. There were no significant associations between the other 4 genes studied and risk of OAC, BO, separately on in combination, in males and females combined or in males only. CONCLUSION: Genetic variants in the oestrogen receptor alpha and the oxytocin receptor may be associated with an increased risk of BO or OAC, but replication in other large samples are needed

Parent-of-origin-specific allelic associations among 106 genomic loci for age at menarche.

Age at menarche is a marker of timing of puberty in females. It varies widely between individuals, is a heritable trait and is associated with risks for obesity, type 2 diabetes, cardiovascular disease, breast cancer and all-cause mortality. Studies of rare human disorders of puberty and animal models point to a complex hypothalamic-pituitary-hormonal regulation, but the mechanisms that determine pubertal timing and underlie its links to disease risk remain unclear. Here, using genome-wide and custom-genotyping arrays in up to 182,416 women of European descent from 57 studies, we found robust evidence (P < 5 × 10(-8)) for 123 signals at 106 genomic loci associated with age at menarche. Many loci were associated with other pubertal traits in both sexes, and there was substantial overlap with genes implicated in body mass index and various diseases, including rare disorders of puberty. Menarche signals were enriched in imprinted regions, with three loci (DLK1-WDR25, MKRN3-MAGEL2 and KCNK9) demonstrating parent-of-origin-specific associations concordant with known parental expression patterns. Pathway analyses implicated nuclear hormone receptors, particularly retinoic acid and γ-aminobutyric acid-B2 receptor signalling, among novel mechanisms that regulate pubertal timing in humans. Our findings suggest a genetic architecture involving at least hundreds of common variants in the coordinated timing of the pubertal transition