Transcript PCORI IBD pathogenesis and personalized therapy, part 1

IBD pathogenesis and
targeted therapies: How
can we improve current
management?
R. Balfour Sartor, M. D.
CCFA Chief Medical Advisor
Midget Distinguished Professor of Medicine,
Microbiology & Immunology
Director, Multidisciplinary IBD Center and
National Gnotobiotic Rodent Resource Center
University of North Carolina- Chapel Hill
Inflammatory Bowel Diseases
CD
UC
 Diffuse inflammation limited to the  Segmental inflammation
involving full thickness of any
mucosa of the colon, involves
part of GI tract
rectum
 Immunologic Profile TH2: IL-13,
activated innate pathways (IL-1b,
IL-6, TNF, IL-12, IL-23)
Genes
HLA
MDR1a
IL-23R
 Immunologic Profile TH1/17:
IL-12, 17, 23, IFNg
activated innate pathways (IL1b, IL-6, TNF)
NOD 2
ATG16L1
IL-23R
2 patients with Crohn’s disease: similar presentations,
different outcomes
Onset: Two 12 y/o boys with failure to grow for one year, anemia
 weight loss, abdominal pain, nonbloody diarrhea
Evaluation: Ileal Crohn’s disease
Treatment: Prednisone, 6MP
Patient A
Patient B
Benign course
Complications:
Feels well, no flares
intra-abdominal abscess,
…………………………. drained, resection of 14” ileum
Post op Infliximab
How to predict which patient will:
• Have an aggressive course?
• Respond to a potential treatment?
• Have complications of disease or therapy?
Understand mechanisms of disease in an
individual at time of diagnosis
Genetic, microbial, immunologic profiles
and clinical phenotype
Fut2
Sartor RB
Gastroenterology 2010
B. Sartor
Gastroenter. 2010
Etiologic Hypothesis of Crohn’s Disease (2014)
• Chronic intestinal inflammation is due to overly aggressive
TH1/17 cell responses to a subset of luminal bacteria
• Susceptibility is determined by genes that encode immune
responses, mucosal barrier function or bacterial clearance
• Onset/reactivation is triggered by environmental stimuli
that transiently break the mucosal barrier and initiate
inflammation
Crohn’s disease
pathogenesis
Microbiota
• ↑ Aggressive
• ↓ Protective
Environmental
Triggers
• Infections
• NSAIDs
• Diet
• Smoking
• Stress
Genetic
Susceptibility
• Barrier Function
• Bacterial Killing
• Immunoregulation
•
163 genes!
Immune Response
• ↑ TH1
• ↑ TH17
• Defective Innate
163 confirmed genetic loci in IBD
CD genes
UC genes
110 IBD loci
NOD2
PTPN22
30 CD
specific
loci
Common pathways:
 Leprosy
 Mycobacterial
susceptibility
 Other immunemediated disease
Genes in common
Jostins, L. et al. Nature 491, 119–124 (01 November 2012)
23 UC
specific
loci
MHC
163 gene mutations associated with Crohn’s disease
and ulcerative colitis
Epithelial Barrier
Immunoregulation
IL-23R (CD and UC)
IL-10 and IL-10R
HLA
Bacterial killing/processing
• OCTN 1/2
– organic cation (carnitine)
transporter
• DLG5
– Scaffolding protein, epithelium
• MDR1a (UC)
– drug transporter, epithelium
• NOD2/CARD15
- intracellular bacterial receptor
• XBP1
- endosomal stress response
ATG 16L1- bacterial autophagy
IRGM- bacterial killing, autophagy
NCF4- NADPH- killing bacteria
NOD2- intracellular killing, antimicrobial peptide secretion
Crohn’s disease
pathogenesis
Microbiota
• ↑ Aggressive
• ↓ Protective
Environmental
Triggers
• Infections
• NSAIDs
• Diet
• Smoking
• Stress
•Antibiotics
Genetic
Susceptibility
• Barrier Function
• Bacterial Killing
• Immunoregulation
Immune Response
• ↑ TH1
• ↑ TH17
• Defective Innate
Environmental Triggers of IBD
Altered mucosal
barrier function
and/or
immunoregulation
Altered microbiota
Acute
infections
Antibiotics
NSAIDs
IBD
Onset and
Reactivation
Diet
Smoking
Stress
Mode of delivery profoundly affects
early colonization of neonates
Dominguez- Bello…R. Knight
PNAS 2010
Vaginally- delivered babies’ microbiota
contains vaginal dominant organisms
(lactobacillus species), while C. section
babies have predominant skin organisms
(Staphlococcus species)
C. section associated with risk of celiac
disease, IBD, NEC, asthma, atopic
dermatitis
Antibiotic use in childhood is a risk factor for
developing Crohn’s disease
(Anders Hviid et al, Gut 60:49-54, 2011)
Prospective, nationwide cohort study of children born
between 1995 – 2003 in Denmark (N= 577,622)
Findings:
•Relative risk increased for IBD (1.84), and selectively for
Crohn’s disease (RR 3.41), but not UC
•Time and dose response: dx within 3 months (RR 4.43) and
>7 courses of antibiotics( RR 7.32)
Conclusion: Unknown causal relationship or association
with IBD symptoms before diagnosis?
Diet influences
Microbiota
(Wu et al,
Science 2011)
Diet determines the composition of gut bacteria
Growth and function of aggressive species by refined sugars and iron;
protective bacteria by complex carbohydrates (fiber, prebiotics)
Injurious
Pro-inflammatory
(Iron, sucrose, fructose, satur. fat)
Bacteroides vulgatus, B. theta
Enterococcus faecalis
E. coli - enteroadherent / invasive
Klebsiella pneumoniae
Bilophila wadsworthia
Bifidobacterium animalis
Fusobacterium varium
Intestinal Helicobacter species
Protective
Anti- inflammatory
(Fiber, prebiotics)
Lactobacillus sp.
Bifidobacterium sp.
Non-pathogenic E. coli
Saccharomyces boulardii
Bacteroides thetaiotaomicron
Faecalibacterium prausnitzii
Clostridium groups IV and XIVA
Crohn’s disease
pathogenesis
Microbiota
• ↑ Aggressive
• ↓ Protective
Environmental
Triggers
• Infections
• NSAIDs
• Diet
• Smoking
• Stress
Genetic
Susceptibility
• Barrier Function
• Bacterial Killing
• Immunoregulation
Immune Response
• ↑ TH1
• ↑ TH17
• Defective Innate
Gastrointestinal Bacteria in Normal Humans
Stomach 0-102
Lactobacillus
Candida
Streptococcus
Helicobacter pylori
Peptostreptococcus
Distal Ileum 107-108
Clostridium
Bacteroides sp
Coliforms
Duodenum 102
Streptococcus
Lactobacillus
Jejunum 102
Streptococcus
Lactobacillus
Colon 1011
Bacteroides
Clostridium coccoides
Clostridium leptum/ Fusobacterium
Bifidobacterium
Coliforms (108)
Proximal Ileum 103
Streptococcus
Lactobacillus
Metabolism in the colonic ecosystem
Polysaccharides
Oligosaccharides
Bacteroides
Bifidobacterium
Lactobacillus
Mucins
Clostridium IV
Clostridium XIVa
E. halli R. hominis
CO2
Lactate
Acetogens
Acetate
clostridia
peptostreptococci
peptococci
Succinate
Clostridium IX
H2
Butyrate
Proteins
SO4--
Sulfate
Reducing
Bacteria
H2S
Ethnogeny
Propionate
Methane
Phenols
NH4+
Amines
Clinical evidence (mostly correlative)
that enteric bacteria, viruses or fungi can induce
Crohn’s disease
•
•
•
•
•
•
•
•
Disease located in areas of highest bacterial populations
Increased mucosal association and translocation
Abnormal composition commensals- dysbiosis
Certain CD- associated genes alter gut microbiota and
bacterial killing
Infections can induce flares of IBD (C. diff toxin, CMV)
Fecal stream diversion prevents CD relapse, disease
recurs upon restoration of fecal flow
Manipulating bacterial populations treats certain subsets
Microbe-specific serologic and T cell responses
Anti-microbial Antibody Sum and Disease Behavior
Frequency of Disease Behavior %
100
P trend < 0.0001
P trend < 0.0001
80
60
40
20
0
* Odds Ratio
Inflammatory
IP (internal penetrating)
S (stenosing)
Surgery
*
1.0
*
1.0
*
2.2
*
1.7
*
5.0
*
4.2
0
1
2
N=199
N=262
N=194
Number of Immune Responses
*
9.5
*
6.1
3
N=57
Dubinsky MC et al CGH 2008;6:1105
IBD: Patient Stratification by Dysbiosis (abnormal composition)
Abnormal
Frank et al., 2007. PNAS. 104(34):13780-13785
Peterson et al, 2008. Cell Host Microbe. 3:417-427
Abnormal
Normal
Normal
IBD-dysbiosis subset is characterized by contraction of
Firmicutes and Bacteroidetes and expansion of
Proteobacteria
IBD-Subset
No
Yes
100
80
60
40
20
0
Frank DN, et al. PNAS 2007;104(34):13780–13785
Proteobacteria
Bacteroidetes
Other
Bacillus
Lachnospiraceae
(Clostridia XIVa/IV)
Firmicutes
% of clone libraries
Actinobacteria
Faecalibacterium prausnitzii is a putative
protective commensal bacterium:
Low mucosal concentrations at surgery predict postoperative recurrence in 20 CD Patients
F. prausnitzii (%)
10
No endoscopic recurrence
Endoscopic recurrence
8
6
*
4
2
0
At surgery
At 6 months
Sokol H et al. Proc Natl Acad Sci U S A. 2008;105:16731.
Insights from gnotobiotic rodents
National Gnotobiotic Rodent Resource Center (NIH, CCFA)
The stage:
A gnotobiotic
isolator
The actors:
Germ-free
Selectively
colonized
(monoassociated)
SPF/ CONV-R
conventionally
SPF raised
CONV-D
conventionalized
Adapted from Jeff Gordon
Essential Role of Commensal Enteric Bacteria in the
Pathogenesis of Experimental Chronic Intestinal
Inflammation
No bacteria
No immune
activation
Mice
IL-2KO ()
IL-10KO
TCRa KO
CD3e26TG
MDR1KO
SAMP1/Yit ()
CD45RBhi SCID
Resident bacteria
Macrophage
and TH1/TH17
immune
activation
Rats
HLA-B27 TG
Indomethacin
Guinea pigs
Carrageenan
No colitis
Non-human primate
Cotton top tamarin
Colitis
Differential ability of various bacterial species
to induce or prevent experimental colitis
All bacterial species are not equal!
HLA B27
transgenic rat
Cecal
bacteria
Bacteroides
vulgatus
Germ free,
no colitis
Cecal bacteria +
Lactobacillus GG
Rath et al., J Clin Invest 1996;98:945
Rath et al., Infect Immunity 1999; 67:2969
Dieleman et.al., Gut 2003; 52:370
Aggressive
colitis
Moderate
colitis
No colitis
E. coli
Protection
Functionally altered E. coli are present in ileal
Crohn’s disease
Adherent/invasive E. coli
•Adhere to/invade epithelial cells
•Persist within EC, macrophages
•Increased in ileal Crohn’s disease
(Darfeuille- Michaud, et al.
Baumgart, Simpson, ISME J. 2007)
•Bind to CEACAM 6 on ileal
epithelial cells
Barnich et al, JCI 2007)
Intestinal inflammation vs. homeostasis depends on the relative
balance of beneficial vs. detrimental bacteria: This balance is unique
in each individual and each individual responds differently to various
bacterial species
Injurious
Pro-inflammatory
Protective
Probiotic
Lactobacillus sp.
Bacteroides vulgatus, B. theta
Bifidobacterium sp.
Enterococcus faecalis
Faecalibacterium prausnitzii
E. coli - adherent / invasive
Roseburia species
Klebsiella pneumoniae
Non-pathogenic E. coli
Ruminococcus gnavus
Segmented filamentous bacterium Saccharomyces boulardii
Bacteroides thetaiotaomicron
Fusobacterium varium
Intestinal Helicobacter species
Crohn’s disease
pathogenesis
Microbiota
• ↑ Aggressive
• ↓ Protective
Environmental
Triggers
• Infections
• NSAIDs
• Diet
• Smoking
• Stress
Genetic
Susceptibility
• Barrier Function
• Bacterial Killing
• Immunoregulation
•
163 genes!
Immune Response
• ↑ TH1
• ↑ TH17
• Defective Innate
Fut2
Sartor RB
Gastroenterology 2010
B. Sartor
Gastroenter. 2010