Tarmbakterier ved fedme og type 2 diabetes

Transcription

1 Tarmbakterier ved fedme og type 2 diabetes Trine Nielsen, læge, ph.d. Novo Nordisk Foundation Center for Basic Metabolic Research Københavns Universitet Landskursus for diabetessygeplejersker 8. november 2014

2 Hvad er tarmmikrobiota of hvordan undersøger vi det? Hvilke faktorer påvirker vores tarmbakterier? Hvad ved vi om tarmbakterier ved fedme og type 2 diabetes? Hvordan vil vi i fremtiden kunne påvirke vores tarmbakterier

3 Ændret opfattelse af vores tarmbakterier Patogene bakterier Bakterier i symbiose med værten Tarmflora METAGENOMICS Mikrobiota PRIS

4 The microbiota of the human gut 100 trillion microorganisms; 10-fold more cells than the human body A collective genome: The microbiome Key functions of the microbiota: >70% of bacterial species can NOT be cultured Colonization barrier Fermentation of non-digestible polysaccharides to produce short chain fatty acids Involved in absoprtion of vitamins and minerals Production of secondary bile acids

5 Methods for studying the microbiota. Karlsson F et al. Diabetes 2013;62: Copyright 2011 American Diabetes Association, Inc.

6 High intra-individual differences in bacterial composition - Similar functional pathways. Oral Fecal Lozupone et al. Nature 89: , 2012

7 100 % 10 %

8 Gut microbiota are associated with diseases Inflammatory Bowel diseases Obesity Rheumatoid arthritis Diabetes Autism Atherosclerosis Multiple sclerosis Asthma Colon Cancer By courtesy of Mani Arumugam Metabolic diseases Neurological disorders Heart diseases Autoimmune diseases Cancer Airway diseases

9 Germ-free mice models to discover mechanisms More insulin sensitive Leaner Larger pool of bile acids

10 Normal gut microbiota modulates brain development and behavior Intestinal microbiota transfer differentially affects behavior of recipient mice GASTROENTEROLOGY 2011;141:599 Section of Metabolic Genetics

11 Gut microbiota are associated with diseases Inflammatory Bowel diseases Obesity Rheumatoid arthritis Diabetes Autism Atherosclerosis Multiple sclerosis Asthma Colon Cancer By courtesy of Mani Arumugam Metabolic diseases Neurological disorders Heart diseases Autoimmune diseases Cancer Airway diseases

12 Mice studies demonstrate a role of the gut microbiota in controlling host metabolism Conventionally raised mice had a 40% higher body fat content than germ free mice. Conventionalisation of germ free mice with donor normal microbiota results in 60 % increase in body fat. Gut microbiota increases the capacity to harvest energy from the diet Gut bacteria induce lipogenesis in liver and triglyceride storage in adipose tissue Ley RE et al. PNAS 102: ,2005 Turnbaugh PJ et al., Nature 444: ,2006

13 Gut Genetics Diet Age Environment Gut bacteria Blood Proinflammatory cytokines Lipopolysaccharide Short-chain fatty acids (acetate to butyrate ratio) Tissues Inflammation Adipogenesis Lipogenesis Inflammation Steatosis Insulin resistance Type 2 diabetes Inflammation

14

15 Obesity is not just obesity Genetic predisposition Life style factors Gut Microbiome 15

16 Clinical characterisation of 292 Danish obese and non-obese individuals All Men Women N Age (yrs) 56 (50-61) 58 (51-64) 56 (50-61) BMI (kg/m 2 ) 31 (24-34) 31 (24-33) 31 (23-34) Body fat percentage (%) 32 (25-39) 26 (21-31) 39 (33-43) P-Glucose (mmol/l) 5.7 ( ) 5.8 ( ) 5.7 ( ) S-Insulin (pmol/l) 45 (26-70) 47 (30-66) 44 (24-74) P-CRP (mg/l) 1.6 ( ) 1.2 ( ) 1.9 ( ) Data are mean and interquartile range 16

17 292 Danish individuals were recruited and phenotyped Anthropometrics FFQ questionnaire Health questionnaire Blood sampling DXA scan Glucose and lipid metabolism Markers of low grade inflammation Adipokines Fecal sampling DNA sequenced 17

18 Using metagenomics to identify gut bacterial genes Fecal sample DNA extracted Sequencing by NGS Identify genes 3.3 M genes 18

19 ndividuals Number of individuals A bimodal distribution was seen dividing the group into 10 low gene count (LGC) 0 and high gene count (HGC) individuals ,000 1,200 LGC individuals: genes HGC individuals: genes Le Chatelier et al. Nature LGC LGC HGC Gene number x 1,000 (all reads) All All Obese Obese Non - obese Non - obese ,000 1,200 Gene number x 1,000 (all reads) HGC All Bacteroides Prevotella Ruminococcus All genes Obese

20 Personer med få gener har øget fedt procent og har øget risiko for udvikling af hjertekarsygdomme og type 2 diabetes end personer med mange gener BMI Fat procent Insulin resistente Cholesterol HS-CRP Frie fede syrer Adiponectin

21 At the species level LGC and HGC individuals can be identified Known species, n=10 Unknown species, n=58 Colors reflect gene abundance 21

22 Bacterial species can differentiate between lean and obese individuals 22

23 368 Chinese T2D patients and controls: Patients with T2D were characterized by Gut microbial dysbiosis Decrease in butyrate-producing bacteria Increase in opportunistic pathogens Section of Metabolic Genetics

24 145 Swedish women with NGT, IFG or T2D Could identify women with T2D like metabolism based on fecal microbiome Association with metformin treatment

25 Forskelle mellem studier Patients with T2D were characterized by Gut microbial dysbiosis Decrease in butyrate-producing bacteria Ethnic or regional differences? Medication? Gender differences? Causality?

26 Can the gut microbiome used to identify individuals at risk? Karlsson et al. LCG vs HGC: AUC of > 0.95 in ROC analyses Qin et al.

27 Discrimination between lean and obese Molecular diagnostic tests?

28 Tarmbakterier Sygdom Kausalitet?

29 Man vs. mouse Most often cross sectional studies Correlatative Mechanistic Causal relations

30 Tarm mikrobiota Sygdom? Metabolisme Immunsystemet

31 Drugs

32

33 Akkermansia muciniphila fed to HFD mice (no metformin) improved glucose tolerance New treatment possibility

34 Does antibiotics affect the risk of obesity?

35 Observed increase in BMI after antibiotics treatment Francois et al. BMC Gastroenterol., 2011; 11: p37 Thuny et al. Plos One, 2010; 5 p e9074

36 Antibiotics in early life increases risk of childhood overweight Antibiotics during the first 6 months of life led to increased risk of overweight among children of normal weight mothers (OR: 1.54, 95% CI: ) Exposure to antibiotics during the first 6 months of life is associated with consistent increases in body mass from 10 to 38 months

37 Decreased insulin sensitivity after vancomycin

38 Low doses of antibiotics affect metabolism Treated mice had higher fat mass Increased hormone levels (GIP) Increased bone mineral density Altered hepatic metabolism of fatty acids and lipids Altered composition of the microbiota Cho, Nature 2012

39 Er det et problem af have få tarmbakterier? Missing microbes??

40 Gut microbiota based interventions It is possible to preserve the gut microbiota? Replacement with a mixture of cultured or fresh healthy bacteria species? Fecal matter transplantation Oral prebiotics or probiotics

41 Can fecal transplantation be used as treatment? C deficile De Wos et al Unpubl. Data CD - nsuccessful UC partly successful

42 FMT in C-difficile infection Van Nood, NEJM 2013

43

44 Transfer of intestinal microbiota from lean donors increases insulin sensitivity 9 transplanted with intestina microbiota from lean controls 9 transplanted with intestina microbiota from themselves Vrieze et al 2012

45 Hvilken funktion har tarmbakterierne? Mediatorer? Via kosten? Kausal effekt? Hvordan medierer de sygdom? Via vores egne gener? Via kortkædede fedtsyrer? Galdesalte Longitudinelle studier Funktionelle studier Biobank

46

47 800

48 Section of Metabolic Genetics Novo Nordisk Foundation Center for Basic Metabolic Research

49 Pas godt på jeres indre venner