Involvement of tissue bacteria in the onset of diabetes in humans: evidence for a concept.

AIMS/HYPOTHESIS: Evidence suggests that bacterial components in blood could play an early role in events leading to diabetes. To test this hypothesis, we studied the capacity of a broadly specific bacterial marker (16S rDNA) to predict the onset of diabetes and obesity in a general population. METHODS: Data from an Epidemiological Study on the Insulin Resistance Syndrome (D.E.S.I.R.) is a longitudinal study with the primary aim of describing the history of the metabolic syndrome. The 16S rDNA concentration was measured in blood at baseline and its relationship with incident diabetes and obesity over 9 years of follow-up was assessed. In addition, in a nested case-control study in which participants later developed diabetes, bacterial phylotypes present in blood were identified by pyrosequencing of the overall 16S rDNA gene content. RESULTS: We analysed 3,280 participants without diabetes or obesity at baseline. The 16S rDNA concentration was higher in those destined to have diabetes. No difference was observed regarding obesity. However, the 16S rDNA concentration was higher in those who had abdominal adiposity at the end of follow-up. The adjusted OR (95% CIs) for incident diabetes and for abdominal adiposity were 1.35 (1.11, 1.60), p = 0.002 and 1.18 (1.03, 1.34), p = 0.01, respectively. Moreover, pyrosequencing analyses showed that participants destined to have diabetes and the controls shared a core blood microbiota, mostly composed of the Proteobacteria phylum (85-90%). CONCLUSIONS/INTERPRETATION: 16S rDNA was shown to be an independent marker of the risk of diabetes. These findings are evidence for the concept that tissue bacteria are involved in the onset of diabetes in humans.

Potential probiotic Bifidobacterium animalis ssp. lactis 420 prevents weight gain and glucose intolerance in diet-induced obese mice.

Alterations of the gut microbiota and mucosal barrier are linked with metabolic diseases. Our aim was to investigate the potential benefit of the potential probiotic Bifidobacterium animalis ssp. lactis 420 in reducing high-fat diet-induced body weight gain and diabetes in mice. In the obesity model, C57Bl/6J mice were fed a high-fat diet (60 energy %) for 12 weeks, and gavaged daily with B. lactis 420 (109 cfu) or vehicle. In the diabetes model, mice were fed a high-fat, ketogenic diet (72 energy % fat) for 4 weeks, with a 6-week subsequent treatment with B. lactis 420 (108-1010 cfu/day) or vehicle, after which they were analysed for body composition. We also analysed glucose tolerance, plasma lipopolysaccharide and target tissue inflammation using only one of the B. lactis 420 groups (109 cfu/day). Intestinal bacterial translocation and adhesion were analysed in a separate experiment using an Escherichia coli gavage. Body fat mass was increased in both obese (10.7 ± 0.8 g (mean ± standard error of mean) vs. 1.86 ± 0.21 g, P<0.001) and diabetic mice (3.01 ± 0.4 g vs. 1.14 ± 0.15 g, P<0.001) compared to healthy controls. Treatment with B. lactis 420 significantly decreased fat mass in obese (7.83 ± 0.67 g, P=0.007 compared to obese with vehicle) and diabetic mice (1.89 ± 0.16 g, P=0.02 for highest dose). This was reflected as reduced weight gain and improved glucose tolerance. Furthermore, B. lactis 420 decreased plasma lipopolysaccharide levels (P<0.001), liver inflammation (P=0.04), and E. coli adhesion in the distal gut (P<0.05). In conclusion, B. lactis 420 reduces fat mass and glucose intolerance in both obese and diabetic mice. Reduced intestinal mucosal adherence and plasma lipopolysaccharide suggest a mechanism related to reduced translocation of gut microbes.

Continuous-wave lasing of a stoichiometric Yb laser material: KYb(WO4)2.

For the first time to the authors' knowledge, continuous-wave laser emission of the stoichiometric crystal KYb(WO4)2 was achieved at 1068 nm. The 125-microm-thin sample was directly water cooled and pumped at 1025 nm by a Ti:sapphire laser. The maximum output power at room temperature was 20 mW.