Meta-analysis of genome-wide association studies of aggressive and chronic periodontitis identifies two novel risk loci.

Periodontitis is one of the most common inflammatory diseases, with a prevalence of 11% worldwide for the severe forms and an estimated heritability of 50%. It is classified into the widespread moderate form chronic periodontitis (CP) and the rare early-onset and severe phenotype aggressive periodontitis (AgP). These different disease manifestations are thought to share risk alleles and predisposing environmental factors. To obtain novel insights into the shared genetic etiology and the underlying molecular mechanisms of both forms, we performed a two step-wise meta-analysis approach using genome-wide association studies of both phenotypes. Genotypes from imputed genome-wide association studies (GWAS) of AgP and CP comprising 5,095 cases and 9,908 controls of North-West European genetic background were included. Two loci were associated with periodontitis at a genome-wide significance level. They located within the pseudogene MTND1P5 on chromosome 8 (rs16870060-G, P = 3.69 × 10-9, OR = 1.36, 95% CI = [1.23-1.51]) and intronic of the long intergenic non-coding RNA LOC107984137 on chromosome 16, downstream of the gene SHISA9 (rs729876-T, P = 9.77 × 10-9, OR = 1.24, 95% CI = [1.15-1.34]). This study identified novel risk loci of periodontitis, adding to the genetic basis of AgP and CP.

Genome-wide association meta-analysis of coronary artery disease and periodontitis reveals a novel shared risk locus.

Evidence for a shared genetic basis of association between coronary artery disease (CAD) and periodontitis (PD) exists. To explore the joint genetic basis, we performed a GWAS meta-analysis. In the discovery stage, we used a German aggressive periodontitis sample (AgP-Ger; 680 cases vs 3,973 controls) and the CARDIoGRAMplusC4D CAD meta-analysis dataset (60,801 cases vs 123,504 controls). Two SNPs at the known CAD risk loci ADAMTS7 (rs11634042) and VAMP8 (rs1561198) passed the pre-assigned selection criteria (PAgP-Ger < 0.05; PCAD < 5 × 10-8; concordant effect direction) and were replicated in an independent GWAS meta-analysis dataset of PD (4,415 cases vs 5,935 controls). SNP rs1561198 showed significant association (PD[Replication]: P = 0.008 OR = 1.09, 95% CI = [1.02-1.16]; PD [Discovery + Replication]: P = 0.0002, OR = 1.11, 95% CI = [1.05-1.17]). For the associated haplotype block, allele specific cis-effects on VAMP8 expression were reported. Our data adds to the shared genetic basis of CAD and PD and indicate that the observed association of the two disease conditions cannot be solely explained by shared environmental risk factors. We conclude that the molecular pathway shared by CAD and PD involves VAMP8 function, which has a role in membrane vesicular trafficking, and is manipulated by pathogens to corrupt host immune defense.

Anti-nuclear autoantibodies in the general German population: prevalence and lack of association with selected cardiovascular and metabolic disorders-findings of a multicenter population-based study.

BACKGROUND: We determined the prevalence of anti-nuclear autoantibodies (ANAs) in the German adult population and examined the association between ANAs and cardiovascular and metabolic disorders. METHODS: We used data and blood samples from the pretest phases of the German National Cohort, obtained from six of the 18 study centers (n = 1199). All centers applied standardized instruments including face-to-face interviews, anthropometric measurements and collection of blood samples. Self-reported histories of diabetes mellitus, heart attack and elevated blood cholesterol and/or lipids were recorded. Height, weight and blood pressure were measured. ANAs were detected using a semi-automated system (AKLIDES®; Medipan GmbH, Dahlewitz, Germany). A positive ANA was defined as a titer ≥ 1:80. ANA were classified as weakly (1:80 or 1:160), moderately (1:320 or 1:640) or strongly (≥1:1280) positive. Specific autoantibodies against nuclear antigens were detected with second-step assays according to the ANA staining pattern. Associations between the assessed disorders and ANA positivity and pattern were examined using sex and age-adjusted mixed-effects logistic regression models. RESULTS: Thirty-three percent (95% confidence interval; 31-36%) of the 1196 participants (measurements could not be obtained from three samples) were ANA positive (titer ≥ 1:80). The proportions of weakly, moderately and strongly positive ANA were 29%, 3.3% and 1.3%, respectively. ANA positivity was more common among women than men across all titers (χ2, p = 0.03). ANA positivity, even when stratified according to height of titer or immunofluorescent pattern, was not associated with diabetes, elevated blood cholesterol and/or lipids, obesity or hypertension. Second-step autoantibody assays were positive in 41 of the 83 samples (49%) tested, with anti-DFS70 (n = 13) and anti-dsDNA (n = 7) being most frequent. These subgroups were too small to test for associations with the disorders assessed. CONCLUSIONS: The prevalence of ANA positivity in the German general population was similar to values reported from other countries. Contrary to other studies, there was no association with selected self-reported and objectively measured cardiovascular and metabolic variables.

Determination of nasal and oropharyngeal microbiomes in a multicenter population-based study - findings from Pretest 1 of the German National Cohort.

We examined acceptability, preference and feasibility of collecting nasal and oropharyngeal swabs, followed by microbiome analysis, in a population-based study with 524 participants. Anterior nasal and oropharyngeal swabs were collected by certified personnel. In addition, participants self-collected nasal swabs at home four weeks later. Four swab types were compared regarding (1) participants' satisfaction and acceptance and (2) detection of microbial community structures based on deep sequencing of the 16 S rRNA gene V1-V2 variable regions. All swabbing methods were highly accepted. Microbial community structure analysis revealed 846 phylotypes, 46 of which were unique to oropharynx and 164 unique to nares. The calcium alginate tipped swab was found unsuitable for microbiome determinations. Among the remaining three swab types, there were no differences in oropharyngeal microbiomes detected and only marginal differences in nasal microbiomes. Microbial community structures did not differ between staff-collected and self-collected nasal swabs. These results suggest (1) that nasal and oropharyngeal swabbing are highly feasible methods for human population-based studies that include the characterization of microbial community structures in these important ecological niches, and (2) that self-collection of nasal swabs at home can be used to reduce cost and resources needed, particularly when serial measurements are to be taken.

A genome-wide association study identifies nucleotide variants at SIGLEC5 and DEFA1A3 as risk loci for periodontitis.

Periodontitis is one of the most common inflammatory diseases, with a prevalence of 11% worldwide for the severe forms and an estimated heritability of 50%. The disease is characterized by destruction of the alveolar bone due to an aberrant host inflammatory response to a dysbiotic oral microbiome. Previous genome-wide association studies (GWAS) have reported several suggestive susceptibility loci. Here, we conducted a GWAS using a German and Dutch case-control sample of aggressive periodontitis (AgP, 896 cases, 7,104 controls), a rare but highly severe and early-onset form of periodontitis, validated the associations in a German sample of severe forms of the more moderate phenotype chronic periodontitis (CP) (993 cases, 1,419 controls). Positive findings were replicated in a Turkish sample of AgP (223 cases, 564 controls). A locus at SIGLEC5 (sialic acid binding Ig-like lectin 5) and a chromosomal region downstream of the DEFA1A3 locus (defensin alpha 1-3) showed association with both disease phenotypes and were associated with periodontitis at a genome-wide significance level in the pooled samples, with P = 1.09E-08 (rs4284742,-G; OR = 1.34, 95% CI = 1.21-1.48) and P = 5.48E-10 (rs2738058,-T; OR = 1.28, 95% CI = 1.18-1.38), respectively. SIGLEC5 is expressed in various myeloid immune cells and classified as an inhibitory receptor with the potential to mediate tyrosine phosphatases SHP-1/-2 dependent signaling. Alpha defensins are antimicrobial peptides with expression in neutrophils and mucosal surfaces and a role in phagocyte-mediated host defense. This study identifies the first shared genetic risk loci of AgP and CP with genome-wide significance and highlights the role of innate and adaptive immunity in the etiology of periodontitis.

Treatment pattern of type 2 diabetes differs in two German regions and with patients' socioeconomic position.

BACKGROUND: Diabetes treatment may differ by region and patients' socioeconomic position. This may be particularly true for newer drugs. However, data are highly limited. METHODS: We examined pooled individual data of two population-based German studies, KORA F4 (Cooperative Health Research in the Region of Augsburg, south), and the HNR (Heinz Nixdorf Recall study, west) both carried out 2006 to 2008. To ascertain the association between region and educational level with anti-hyperglycemic medication we fitted poisson regression models with robust error variance for any and newer anti-hyperglycemic medication, adjusting for age, sex, diabetes duration, BMI, cardiovascular disease, lifestyle, and insurance status. RESULTS: The examined sample comprised 662 participants with self-reported type 2 diabetes (KORA F4: 83 women, 111 men; HNR: 183 women, 285 men). The probability to receive any anti-hyperglycemic drug as well as to be treated with newer anti-hyperglycemic drugs such as insulin analogues, thiazolidinediones, or glinides was significantly increased in southern compared to western Germany (prevalence ratio (PR); 95% CI: 1.12; 1.02-1.22, 1.52;1.10-2.11 respectively). Individuals with lower educational level tended to receive anti-hyperglycemic drugs more likely than their better educated counterparts (PR; 95% CI univariable: 1.10; 0.99-1.22; fully adjusted: 1.10; 0.98-1.23). In contrast, lower education was associated with a lower estimated probability to receive newer drugs among those with any anti-hyperglycemic drugs (PR low vs. high education: 0.66; 0.48-0.91; fully adjusted: 0.68; 0.47-0.996). CONCLUSIONS: We found regional and individual social disparities in overall and newer anti-hyperglycemic medication which were not explained by other confounders. Further research is needed.

Lipid-peroxidation and peroxiredoxin-overoxidation in the erythrocytes of non-insulin-dependent type 2 diabetic men during acute exercise.

Single bouts of exercise induce an acute state of oxidative stress. It is largely unknown what this means in the context of diseases which are associated with increased oxidative stress, e.g., type 2 diabetes mellitus (T2DM). Free radicals can destroy the structure of erythrocytes and reduce their deformability. Antioxidative peroxiredoxins are highly abundant in erythrocytes. Therefore, we immunohistochemically examined whether the free radical-induced erythrocyte lipid-peroxidation measured by 8-iso-prostaglandin-F2α (8-Iso-PGF) as well as the erythrocyte contents of overoxidized peroxiredoxins (PRDX-SO(2-3)) differ between overweight/obese T2DM men (n = 15, years = 59 ± 10 (mean ± SD)) and overweight/obese non-diabetic control subjects (n = 12, years = 53 ± 4) during acute exercise (WHO-step test). We further studied whether physical training affects the oxidative stress response to acute exercise. Seven men belonging to the diabetic group took part in a moderate intensity cycling endurance training. Erythrocyte 8-Iso-PGF significantly increased during acute exercise and decreased in the 30-min recovery phase in untrained diabetic and non-diabetic men (P ≤ 0.05). Increases/decreases in 8-Iso-PGF in relation to exercise/recovery time were similar in both groups. A significant exercise-induced increase in the contents of erythrocyte PRDX-SO(2-3) was only observed in T2DM men (P ≤ 0.05). PRDX-SO(2-3) contents were not reduced during recovery. Following physical training, the magnitude of exercise-induced increases in 8-Iso-PGF (relative to exercise time) was significantly lower in the erythrocytes of T2DM men (P ≤ 0.05), whereas increases in PRDX-SO(2-3) were significantly higher (P ≤ 0.05). Exercise-induced erythrocyte lipid-peroxidation is similar in untrained overweight/obese T2DM patients and overweight/obese control subjects, while antioxidative mechanisms differ. Physical training might improve oxidative stress in T2DM men's erythrocytes during acute exercise.