The Saliva Metabolome in Association to Oral Health Status.

Periodontitis is one of the most prevalent oral diseases worldwide and is caused by multifactorial interactions between host and oral bacteria. Altered cellular metabolism of host and microbes releases a number of intermediary end products known as metabolites. There is an increasing interest in identifying metabolites from oral fluids such as saliva to widen the understanding of the complex pathogenesis of periodontitis. It is believed that some metabolites might serve as indicators toward early detection and screening of periodontitis and perhaps even for monitoring its prognosis in the future. Because contemporary periodontal screening methods are deficient, there is an urgent need for novel approaches in periodontal screening procedures. To this end, we associated oral parameters (clinical attachment level, periodontal probing depth, supragingival plaque, supragingival calculus, number of missing teeth, and removable denture) with a large set of salivary metabolites ( n = 284) obtained by mass spectrometry among a subsample ( n = 909) of nondiabetic participants from the Study of Health in Pomerania (SHIP-Trend-0). Linear regression analyses were performed in age-stratified groups and adjusted for potential confounders. A multifaceted image of associated metabolites ( n = 107) was revealed with considerable differences according to age groups. In the young (20 to 39 y) and middle-aged (40 to 59 y) groups, metabolites were predominantly associated with periodontal variables, whereas among the older subjects (≥60 y), tooth loss was strongly associated with metabolite levels. Metabolites associated with periodontal variables were clearly linked to tissue destruction, host defense mechanisms, and bacterial metabolism. Across all age groups, the bacterial metabolite phenylacetate was significantly associated with periodontal variables. Our results revealed alterations of the salivary metabolome in association with age and oral health status. Among our comprehensive panel of metabolites, periodontitis was significantly associated with the bacterial metabolite phenylacetate, a promising substance for further biomarker research.

Kappa free light chains in cerebrospinal fluid to identify patients with oligoclonal bands.

BACKGROUND AND PURPOSE: The gold standard for detection of intrathecal immunoglobulin synthesis is the measurement of oligoclonal bands (OCB). In the diagnosis of multiple sclerosis, the kappa free light chains (KFLC) index has a similar sensitivity and specificity as OCB. This study investigated whether determination of the KFLC index could be used to predict the presence of OCB. METHODS: The KFLC index was determined prospectively from 295 paired serum and cerebrospinal fluid samples. KFLC were determined by nephelometry using the N Latex FLC kappa kit (Siemens Healthcare Diagnostics Products GmbH) on the BN Prospec analyzer (Siemens Healthcare Diagnostics Products GmbH) (cohort I). A cut-off value was determined using receiver operating characteristic analysis in relation to OCB positivity. These results were validated prospectively in 96 samples (cohort II) as well as retrospectively in samples of 46 patients known to be OCB positive (cohort III). We also compared the agreement of two commercially available nephelometric KFLC assays. RESULTS: In cohort I, a KFLC index of 3.61 yielded 100% sensitivity and 88% specificity. Prospective validation of this cut-off value in cohort II showed 92% sensitivity and 96% specificity. In cohort III, a sensitivity of 93% was achieved. Comparison of Siemens and Binding Site (Birmingham, UK) assays revealed good agreement (r2  = 0.86). CONCLUSIONS: The KFLC index with a cut-off value of 3.61 had high diagnostic accuracy to predict immunoglobulin G synthesis via OCB analysis. Determination of the KFLC index provided a quantitative parameter that could be used as an initial diagnostic step in inflammatory central nervous system disorders before measuring OCB.

Abdominal fat deposits determined by magnetic resonance imaging in relation to leptin and vaspin levels as well as insulin resistance in the general adult population.

BACKGROUND: Various fat depots including visceral (VAT), subcutaneous adipose tissue (SAT) or liver fat content (LFC) were supposed to have different influences on various entities including adipokine levels as well as insulin resistance/sensitivity. Therefore, the aim of the study was to investigate the associations of SAT, VAT and LFC with the levels of leptin and vaspin as well as insulin resistance in a general non-diabetic population. METHODS: In total, 1825 participants of the Study of Health in Pomerania were characterized according to body fat compartments and LFC determined by magnetic resonance imaging. Of those subjects, insulin resistance (HOMA-IR) and insulin sensitivity ([ISI(comp)) were determined in 981 participants and adipokines were assessed in 698 using enzyme-linked immunosorbent assay. Analyses of variance and linear regression models adjusted for age, sex, smoking, height, physical inactivity and alcohol consumption were used for analysis. RESULTS: Using the residual method to assess independently the effect of the various fat depots, a strong positive association of SAT (beta per standard deviation (s.d.) increase 0.54 (95% confidence interval (CI) 0.47-0.60)) but not VAT (beta 0.01 (95% CI -0.08 to 0.09)) and LFC (beta 0.01 (95% CI -0.06 to 0.08)) with log2-leptin levels was found independent of the HOMA-IR status. Moreover, a positive association of LFC (beta 0.17 (95% CI 0.07-0.26)) with log2-vaspin levels becomes apparent, which were mostly driven by subjects with a low HOMA-IR. With respect to HOMA-IR and ISI(comp) index, pronounced positive and inverse associations to all fat markers were revealed, respectively, with the strongest relation found for SAT and LFC. CONCLUSIONS: SAT and LFC were identified as predominant sites associated with leptin and vaspin levels, respectively. Residual analysis pointed towards a general adverse effect of disproportional triglyceride storage across physiological despots, in particular in ectopic sides such as the liver, with markers of insulin resistance.

Identification of urine metabolites associated with 5-year changes in biomarkers of glucose homoeostasis.

AIM: Metabolomics provides information on pathogenetic mechanisms and targets for interventions, and may improve risk stratification. During the last decade, metabolomics studies were used to gain deeper insight into the pathogenesis of diabetes mellitus. However, longitudinal metabolomics studies of possible subclinical states of disturbed glucose metabolism are limited. Therefore, the aim of this study was to analyze the associations between baseline urinary metabolites and 5-year changes in continuous markers of glucose homoeostasis, including fasting glucose, HbA1c and homoeostasis model assessment of insulin resistance (HOMA-IR) index values. METHODS: Urine metabolites in 3986 participants at both baseline and 5-year follow-up of the population-based Inter99 study were analyzed by 1H-NMR spectroscopy. Linear regression and analyses of covariance models were used to detect associations between urine metabolites and 5-year changes in markers of glucose homoeostasis. RESULTS: Higher baseline levels of urinary alanine, betaine, N,N-dimethylglycine (DMG), creatinine and trimethylamine were associated with an increase in HbA1c from baseline to follow-up. In contrast, formic acid and trigonelline levels were associated with a decrease in HbA1c over time. Analyses of 5-year changes in fasting glucose and HOMA-IR index showed similar findings, with high baseline levels of lactic acid, beta-d-glucose, creatinine, alanine and 1-methylnicotinamide associated with increases in both parameters. CONCLUSION: Several urine metabolites were found to be associated with detrimental longitudinal changes in biomarkers of glucose homoeostasis. The identified metabolites point to mechanisms involving betaine and coffee metabolism as well as the possible influence of the gut microbiome.

Thyrotropin serum levels are differentially associated with biochemical markers of bone turnover and stiffness in women and men: results from the SHIP cohorts.

UNLABELLED: In two large German population-based cohorts, we showed positive associations between serum thyrotropin (TSH) concentrations and the Fracture Risk Assessment score (FRAX) in men and positive associations between TSH concentrations and bone turnover markers in women. INTRODUCTION: The role of thyroid hormones on bone stiffness and turnover is poorly defined. Existing studies are confounded by differences in design and small sample size. We assessed the association between TSH serum concentrations and bone stiffness and turnover in the SHIP cohorts, which are two population-based cohorts from a region in Northern Germany comprising 2654 men and women and 3261 men and women, respectively. METHODS: We calculated the bone stiffness index using quantitative ultrasound (QUS) at the calcaneus, employed FRAX score for assessment of major osteoporotic fractures, and measured bone turnover markers, N-terminal propeptide of type I procollagen (P1NP), bone-specific alkaline phosphatase (BAP), osteocalcin, and type I collagen cross-linked C-telopeptide (CTX) in all subjects and sclerostin in a representative subgroup. RESULTS: There was no association between TSH concentrations and the stiffness index in both genders. In men, TSH correlated positively with the FRAX score both over the whole TSH range (p < 0.01) and within the reference TSH range (p < 0.01). There were positive associations between TSH concentrations and P1NP, BAP, osteocalcin, and CTX (p < 0.01) in women but not in men. There was no significant association between TSH and sclerostin levels. CONCLUSIONS: TSH serum concentrations are associated with gender-specific changes in bone turnover and stiffness.