The document discusses the gut-brain axis and probiotics. It begins by noting that the gut-brain axis is a complex bidirectional system integrating the host and microbiota. It then provides an overview of the key components of the gut-brain axis, including the neuroanatomical pathways, neuroendocrine pathways, immune pathways, microbiota and metabolism, and intestinal barriers. Several studies are summarized that demonstrate gut-brain axis interactions using germ-free mice models and human evidence from irritable bowel syndrome patients. Finally, emerging clinical studies on probiotics and the gut-brain axis are highlighted, including a functional MRI study showing probiotic consumption can decrease brain reactivity to negative stimuli.

1. Gut Microbiota and Probiotic Science Foundation [India]
3rd – 4th December 2016, ITC Grand Chola, Chennai, India
8TH India Probiotic Symposium
Probiotics in Health - Emerging Opportunities
Raphaël MORIEZ , PhD
Department of Life Sciences - Clinical Studies & Biometry
Nutribiotic & Microbes for Health Team
Centre de Recherche Daniel Carasso, Palaiseau
GUT-BRAIN AXIS &
PROBIOTICS
© Reproduction, even partial, is not authorized I R.MORIEZ

2. Gut-Brain Axis is more than an emerging concept
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3. To have in mindbefore the presentation….
• Gut-Brain axis - a misleading term differentially used to named:
=> Neuroanatomical pathways between Gastrointestinal tract & brain [pathway of visceral
pain…]
=> Neuro -endocrine -immune communications between GI tract & brain...
• Gut-Brain axis is more complex, and is an INTEGRATIVE SYSTEM,
BIDIRECTIONAL that integrates all dimensions of the host and of it’s
microbiota
Brain-Gut Axis

Brain-Gut-Intestinal Microbiota Axis
GUT-BRAIN AXIS| R. MORIEZ

4. • Introduction to the Gut-Brain axis with preclinical and clinical
data
• Probiotics are an interesting route to consider in the
management of syndromes/pathologies associated with Gut-
Brain axis dysfunction
TODAY’sTALK
GUT-BRAIN AXIS| R. MORIEZ

5. ❸ Neuroanatomical
pathway of gut-brain
axis
❹
Neuroendocrine
HPA axis
pathway
❺Gut immune
system &
neuroimmune
pathways
❻ Gut
microbiota &
metabolism
system
❼ Intestinal
barrier
& blood brain
barrier
❷ Gut microbiota
❶ Brain
How the Gut-Brain Axis works
GUT-BRAIN AXIS| R. MORIEZ

6. • enteric NS
• parasympathetic NS
• sympathetic NS
• CRF, ACTH, cortisol • mast cells,
macrophages..
• Cytokines, PGs…
• Proteases
• GABA, Dopamine,
serotonin…
• LPS, SCFA…
• Epithelial/Enteroendocr
ne cells
• Tight Jcts/permeability
How the Gut-Brain Axis works– The key Actors
❸ Neuroanatomical
pathway of gut-brain
axis
❹
Neuroendocrine
HPA* axis
pathway
❺Gut immune
system &
neuroimmune
pathways
❻ Gut
microbiota &
metabolism
system
❼ Intestinal
barrier
& blood brain
barrier
❷ Gut microbiota
❶ Brain
*Hypothalamic–pituitary–adrenal
GUT-BRAIN AXIS| R. MORIEZ

7. life style diet dietary proteins antibiotic xenobiotic food allergies infections
How the Gut-Brain Axis works– The key Actors & Modulators
❷ gut microbiota
❶ brain
❸ neuroanatomical
pathway of gut-brain axis
❹ neuroendocrine
HPA axis pathway
❺gut immune system &
neuroimmune pathways
❻ gut microbiota
& metabolism
system
❼ intestinal barrier
& blood brain barrier
life style stress hormones aging genetic diet infections / chronic pathologies & treatments
• enteric NS
• parasympathetic NS
• sympathetic NS
• CRF, ACTH, cortisol • mast cells, macrophages..
• Cytokines, PGs…
• Proteases
• GABA, Dopamine,
serotonin…
• LPS, SCFA…
• Epithelial/Enteroendocrine
cells
• Tight Jcts/permeability
GUT-BRAIN AXIS| R. MORIEZ

8. Differents approaches to demonstrate Gut-Brain axis interaction
PreclinicalResearch
Cryan & Dinan, Nature Neurosci Rev (2012)
GUT-BRAIN AXIS| R. MORIEZ

9. Differents approaches to demonstrate Gut-Brain axis interaction
PreclinicalResearch
Cryan & Dinan, Nature Neurosci Rev (2012)
GUT-BRAIN AXIS| R. MORIEZ

10. • Research using GF mice has arguably provided the most convincing
evidence for a role of microbiota in gut-brain signaling
• One of the main advantages of the GF model is that identical strains of
bacteria can be introduced and GF mice can be « humanized » by
transplanting fecal microbiota from human patients with different
diseases.
Differents approaches to demonstrate Gut-Brain axis interaction
PreclinicalResearch
GUT-BRAIN AXIS| R. MORIEZ

11. HPA axis responseis influence bygut microbiotacomposition
Germ Free [GF] Specific Pathogen
Free [SPF]
Germ Free [GF]
Germ Free [GF]
B. infantis EPEC Mutant EPEC Tir
[SPF]
GERM FREE vs. SPECIFIC PATHOGEN FREE MONOASSOCIATED FLORA FECAL TRANSPLANTATION
vs.
Acute Restraint Stress [1h] => measure of plasmatic corticosterone
Sudo et al., J Physiol (2004)
*Tir (translocated intimin receptor) is an essential component in the adherence of E.coli
*
PreclinicalResearch
GUT-BRAIN AXIS| R. MORIEZ

12. The body of Evidence of Gut-Brain axis interaction in GF models
Luczynski P et al., Int J.of Neuropsychopharmacology (2016)
PreclinicalResearch
GUT-BRAIN AXIS| R. MORIEZ

13. Can we transposepreclinical data to humans?
?  Experimentally, Technically & Ethically
difficult to investigate Gut brain
mechanism and its components
[microbiota, GIT & brain biopsy….]
 Brain structure, microbiota composition
is different in humans compared to
animal models…
No direct evidence of a gut-brain-
microbiota interaction in human [How it
works], but a robust and coherent level of
indirect evidence
GUT-BRAIN AXIS| R. MORIEZ

14. ❸ neuroanatomical
pathway of gut-brain axis
❹ neuroendocrine
HPA axis pathway
❺gut immune system &
neuroimmune pathways
❻ gut microbiota
& metabolism
system
❼ intestinal barrier
& blood brain barrier
❷ gut microbiota
❶ brain
Gut-Brain Axis in Human– IBS as model of evidence
GUT-BRAIN AXIS| R. MORIEZ

15. ❸ neuroanatomical
pathway of gut-brain axis
❹ neuroendocrine
HPA axis pathway
❺gut immune system &
neuroimmune pathways
❻ gut microbiota
& metabolism
system
❼ intestinal barrier
& blood brain barrier
❷ gut microbiota
❶ brain
Gut-Brain Axis in Human– IBS as model of evidence
Enck P et al., Nature Reviews I Disease Primers (2016)
GUT-BRAIN AXIS| R. MORIEZ

16. ❸ neuroanatomical
pathway of gut-brain axis
❹ neuroendocrine
HPA axis pathway
❺gut immune system &
neuroimmune pathways
❻ gut microbiota
& metabolism
system
❼ intestinal barrier
& blood brain barrier
❷ gut microbiota
❶ brain
The other Troubles & Pathologies where Gut-Brain is altered
Stress
Stress
Stress Stress
Stress
Autism
Autism
Autism
Autism
Autism
Autism
Autism
mood disorders
psychiatric diseases
metabolic disorders
Obesity
T2DM
Obesity
T2DM
Obesity
T2DM
Obesity
T2DM
Obesity
T2DM
Obesity
T2DM
GI diseases
IBD
IBD
IBD
IBD
IBD IBD
GUT-BRAIN AXIS| R. MORIEZ

17. ❸ neuroanatomical
pathway of gut-brain axis
❹ neuroendocrine
HPA axis pathway
❺gut immune system &
neuroimmune pathways
❻ gut microbiota
& metabolism
system
❼ intestinal barrier
& blood brain barrier
❷ gut microbiota
❶ brain
Gut-Brain Interaction - Impact on Health ?
Stress
Stress
Stress Stress
Stress
Autism
Autism
Autism
Autism
Autism
Autism
mood disorders
Class of pathologies
psychiatric diseases
metabolic disorders
Obesity
T2DM
Obesity
T2DM
Obesity
T2DM
Obesity
T2DM
Obesity
T2DM
GI diseases
IBD
IBD
IBD
IBD
IBD
Gut
Brain
Gut Brain
vicious circle
Chicken or egg ?
stress, ATB
diet & life style…
HEALTHY Behavior changes
Syndromes
Pathologies
GUT-BRAIN AXIS| R. MORIEZ

18. Clinical studies with probioticsin the Gut-Brain Axis
• A growing wave of striking clinical studies mainly focused on response to
emotional attention tasks, mood disorders, stress, anxiety & depression.
• In order to evaluate levels of stress, brain activity and psychological symptoms in
clinical studies, several tools have been applied, including biomarkers (i.e. salivary
cortisol), brain MRI and validated psychological scales typically used for the
evaluation of anxiolytic drugs.
Pirbaglou M et al., Nutrition Research (2016)
GUT-BRAIN AXIS| R. MORIEZ

19. The evidence of a gut-brain interaction using FMRI*
*FMRI. Functional Magnetic Resonance Imaging
Objective:
To assess the effect of a 4-week consumption of Fermented Milk Product (FMP: 5 strains
of probiotics including B. animalis lactis DN 173 010B) (2x125g/day) on brain intrinsic
connectivity and responses to emotional attention task in healthy women.
Sample size: 36 subjects (ITT = Intention To Treat; 45 randomized)
12 in the FMP arm
11 in the CONTROL arm
13 in the NO INTERVENTION (NO IN) arm
Inclusion criteria:
Healthy women
Age 18-55
No chronic pain
No gastrointestinal symptoms
No psychiatric illness
Right handed
Tillisch K, Gastroenterology (2013)
GUT-BRAIN AXIS| R. MORIEZ

20. The evidence of a gut-brain interaction using FMRI*
Tillisch K, Gastroenterology (2013)
GUT-BRAIN AXIS| R. MORIEZ

21. The evidence of a gut-brain interaction using FMRI*
Assessment of regional cerebral activity at resting state and
following a negative emotional attention task
Emotional
Matching
Emotional
Matching
Matched
Emotion (ME)
Emotional
Matching
Emotion
Labellin
Emotional
Matching
Emotion
Labellin
Matched
Emotion (ME)
ID Emo
(IDE)
Co
1) Resting state: eyes closed for a 5 minutes
functional scan; no stimulation
2) Negative emotional attention task:
– Validated task probing attention to
negative context (Lieberman, 2007)
– Assess the brain response while
viewing human negative emotional
faces (angry or fearful expressions) and
matching shapes as a control
Tillisch K, Gastroenterology (2013)
GUT-BRAIN AXIS| R. MORIEZ

22. The evidence of a gut-brain interaction using FMRI*
Study Results: Emotional attention task - 1/2
• 4 week FMP consumption decreases reactivity to a negative emotional attention
task of a brain network receiving afferent signals from the gut:
– FMP group: decreased reactivity of a widely distributed brain network (insula,
somatosensory cortex, PAG) to the task (p<0.0001)
– Control group: no change in the reactivity of the brain network to the task
– No IN group: increased reactivity of the brain network to the task
No IN
FMPP
Emotional
Matching
Sha
Matc
Emotional
Labelling
Conditions
Emotional
Matching
Sha
Matc
Emotional
Labelling
Conditions
Matched
Emotion (ME)
Matc
Form
ID Emotion
(IDE)
nal
ng
Shape
Matching
Emotional
Labelling
Conditions
nal
ng
Shape
Matching
Emotional
Labelling
Conditions
d
n (ME)
Matched
Forms (MF)
ID Emotion
(IDE)
Conditions
(PAG)
Tillisch K, Gastroenterology (2013)
GUT-BRAIN AXIS| R. MORIEZ

23. The evidence of a gut-brain interaction using FMRI*
Emotional
Matching
Sha
Matc
Emotional
Labelling
Conditions
Emotional
Matching
Sha
Matc
Emotional
Labelling
Conditions
Matched
Emotion (ME)
Matc
Form
ID Emotion
(IDE)
nal
ng
Shape
Matching
Emotional
Labelling
Conditions
nal
ng
Shape
Matching
Emotional
Labelling
Conditions
d
n (ME)
Matched
Forms (MF)
ID Emotion
(IDE)
Conditions
Study Results: Emotional attention task - 2/2
• Individual analyses of the regions from the identified network support previous
network results for the 3 groups
• 4 week FMP consumption decreases reactivity of interoceptive (mid-insula) and
somatosensory regions to a negative emotional attention task, compared to NO IN
(p<0.004; p<0.005) and CONTROL (p<0.03; p<0.02)
No IN > FMPP
Control > FMPP
Tillisch K, Gastroenterology (2013)
GUT-BRAIN AXIS| R. MORIEZ

24. The evidence of a gut-brain interaction using FMRI*
CONCLUSION.
• To our knowledge, this is the first demonstration in humans that chronic intake of a
fermented milk product with probiotic can modulate brain activity
• The findings suggest that regular intake of a fermented milk product with probiotic
can (i) affect brain regions concerned with the central processing of afferent signals
from the gut, and (ii) reduce the impact of the brain regions involved in emotional
arousal on the central processing of gut afferent signals
• Moreover, 4 week FMP consumption induced a shift away from an emotional arousal-
based resting state network towards a rationalization network
Tillisch K, Gastroenterology (2013)
GUT-BRAIN AXIS| R. MORIEZ

25. The evidence of a gut-brain interaction using BIOMARKER
Takada M, Neurogastroenterology & Motility (2016)
Objective:
Three double-blind, placebo-controlled trials were conducted to examine the effects of
of a 8-week consumption of Lactobacillus casei strain Shirota (once daily) on
psychological and physiological (BIOMARKER Cortisol) stress responses in healthy
medical students under academic examination stress.
Sample size: 140 subjects
70 in the placebo arm
70 in the LcS arm
GUT-BRAIN AXIS| R. MORIEZ

26. The evidence of a gut-brain interaction using BIOMARKER
Takada M, Neurogastroenterology & Motility (2016)
Study Results:
Ingestion of LcS suppressed stress-induced increases in glucocorticoids in an academic
stress model in healthy medical students
GUT-BRAIN AXIS| R. MORIEZ

27. How does it work ? Possible mechanisms.
B. longum strains on anxiety
=> vagus nerves, brain BDNF pathways
L. rhamnosus strains on anxiety & depression
 GABA upregulation in brain
L. helveticus strains on anxiety
 ↘ neuroinflammation, ↘ serotonin
metabolism
B. Animalis strains properties
 Inhibitor of Monoamine oxidase
(allow serotonin, dopamine..to remain in
Synaptic cleft ?) / scavenged free radicals
Exact mechanism of action of probiotics on Gut-Brain still remains to be established but
combining intrinsic properties of strains and the Preclinical & Clinical data we can
speculate that probiotics impact all the component of Gut-Brain axis (microbiota, barrier,
immune system, enteric nervous system, vagus nerves, brain).
GUT-BRAIN AXIS| R. MORIEZ

28. Conclusion
• A growing list of disorders – IBS, depression and autism
spectrum disorders - recently recognized as brain-gut
disorders
• Potential for novel therapeutic interventions at the
microbiome or at the gut level
• Probiotics have potential as agents to manage these
syndromes/pathologies associated with Gut-Brain axis
dysfunction
GUT-BRAIN AXIS| R. MORIEZ

29. “Let food be thy medicine and
medicine be thy food.”
Hippocrates (c. 460 BC – c. 370 BC)
GUT-BRAIN AXIS| R. MORIEZ