Background: The gut-brain axis refers to the network of connections that involve multiple biologic systems, allowing bidirectional communication between the gut and the brain. This communication is mainly mediated by gut microbiota, thanks to its ability to modulate several processes like the production of neurotransmitters. As such, keeping a balanced gut microbiota through probiotic intake could be a valid solution in supporting the right gut-brain communications. Methods: A two-step in vitro screening of five different probiotic strains was carried out to select the best performers in the modulation of stress markers. A first selection on SK-N-DZ neuronal cell lines was performed to evaluate the inhibition of the epigenetic enzyme LSD1, promotion of GABA, and expression of serotonin. Three out of five strains were tested for their ability to promote serotonin synthesis in the Caco2 cell line. As a result, Limosilactobacillus reuteri PBS072 and Bifidobacterium breve BB077 were selected as the best performing strains. To confirm their effects in humans, a proof-of-concept trial was carried out to evaluate stress-related parameters for 28 days of product intake in a group of 30 stressed students. Results: A significant improvement of cognitive functions, in terms of short-term memory, attention, and executive performance, as well as of psychophysiological markers, such as salivary cortisol level, skin conductance, sleep quality, and anxiety, were observed. Conclusions: According to the results, L. reuteri PBS072 and B. breve BB077 are potential probiotic candidates for improving stress resilience, cognitive functions, and sleep quality.

1.
Carabotti
M
,
Scirocco
A
,
Maselli
MA
,
Severi
C
.
The gut-brain axis: interactions between enteric microbiota, central and enteric nervous systems
.
Ann Gastroenterol
.
2015
;
28
:
203
9
.
2.
Taché
Y
,
Vale
W
,
Rivier
J
,
Brown
M
.
Brain regulation of gastric secretion: influence of neuropeptides
.
Proc Natl Acad Sci U S A
.
1980 Sep
;
77
(
9
):
5515
9
. .
3.
Mayer
EA
,
Tillisch
K
,
Gupta
A
.
Gut/brain axis and the microbiota
.
J Clin Invest
.
2015
;
125
:
926
38
. .
4.
Silva
YP
,
Bernardi
A
,
Frozza
RL
.
The role of short-chain fatty acids from gut microbiota in gut-brain communication
.
Front Endocrinol
.
2020 Jan 31
;
11
:
25
. .
5.
Galland
L
.
The gut microbiome and the brain
.
J Med Food
.
2014 Dec
;
17
(
12
):
1261
72
. .
6.
Foster
JA
,
Rinaman
L
,
Cryan
JF
.
Stress & the gut-brain axis: regulation by the microbiome
.
Neurobiol Stress
.
2017 Mar 19
;
7
:
124
36
.
7.
Kelly
JR
,
Kennedy
PJ
,
Cryan
JF
,
Dinan
TG
,
Clarke
G
,
Hyland
NP
.
Breaking down the barriers: the gut microbiome, intestinal permeability and stress-related psychiatric disorders
.
Front Cell Neurosci
.
2015
;
9
:
392
. .
8.
Liu
RT
.
The microbiome as a novel paradigm in studying stress and mental health
.
Am Psychol
.
2017
;
72
:
655
67
. .
9.
Fröhlich
EE
,
Farzi
A
,
Mayerhofer
R
,
Reichmann
F
,
Jačan
A
,
Wagner
B
,
Cognitive impairment by antibiotic-induced gut dysbiosis: analysis of gut microbiota-brain communication
.
Brain Behav Immun
.
2016
;
56
:
140
55
. .
10.
Bailey
MT
.
Psychological stress, immunity, and the effects on indigenous Microflora
.
Adv Exp Med Biol
.
2016
;
874
:
225
46
. .
11.
Gao
X
,
Cao
Q
,
Cheng
Y
,
Zhao
D
,
Wang
Z
,
Yang
H
,
Chronic stress promotes colitis by disturbing the gut microbiota and triggering immune system response
.
Proc Natl Acad Sci U S A
.
2018
;
115
:
E2960
9
. .
12.
Tilocca
B
,
Pieroni
L
,
Soggiu
A
,
Britti
D
,
Bonizzi
L
,
Roncada
P
,
Gut-brain axis and neurodegeneration: state-of-the-art of meta-omics sciences for microbiota characterization
.
Int J Mol Sci
.
2020
;
21
:
4045
. .
13.
Papalini
S
,
Michels
F
,
Kohn
N
,
Wegman
J
,
Van Hemert
S
,
Roelofs
K
,
Stress matters: randomized controlled trial on the effect of probiotics on neurocognition
.
Neurobiol Stress
.
2018
;
10
:
100141
. .
14.
Zhang
N
,
Liao
X
,
Zhang
Y
,
Li
M
,
Wang
W
,
Zhai
S
.
Probiotic supplements for relieving stress in healthy participants: a protocol for systematic review and meta-analysis of randomized controlled trials
.
Medicine
.
2019
;
98
:
e15416
. .
15.
Yano
JM
,
Yu
K
,
Donaldson
GP
,
Shastri
GG
,
Ann
P
,
Ma
L
,
Indigenous bacteria from the gut microbiota regulate host serotonin biosynthesis
.
Cell
.
2015
;
161
:
264
76
. .
16.
Mazzoli
R
,
Pessione
E
.
The neuro-endocrinological role of microbial glutamate and GABA signaling
.
Front Microbiol
.
2016
;
7
:
1934
. .
17.
Sarkar
A
,
Lehto
SM
,
Harty
S
,
Dinan
TG
,
Cryan
JF
,
Burnet
PWJ
.
Psychobiotics and the manipulation of bacteria-gut-brain signals
.
Trends Neurosci
.
2016
;
39
:
763
81
. .
18.
Nuss
P
.
Anxiety disorders and GABA neurotransmission: a disturbance of modulation
.
Neuropsychiatr Dis Treat
.
2015
;
11
:
165
75
. .
19.
Bacqué-Cazenave
J
,
Bharatiya
R
,
Barrière
G
,
Delbecque
JP
,
Bouguiyoud
N
,
Di Giovanni
G
,
Serotonin in animal cognition and behavior
.
Int J Mol Sci
.
2020
;
21
:
1649
. .
20.
Vineis
P
,
Chatziioannou
A
,
Cunliffe
VT
,
Flanagan
JM
,
Hanson
M
,
Kirsch-Volders
M
,
Epigenetic memory in response to environmental stressors
.
FASEB J
.
2017
;
31
:
2241
51
. .
21.
Morales-Lara
D
,
De-la-Peña
C
,
Murillo-Rodríguez
E
.
Dad’s snoring may have left molecular scars in Your DNA: the emerging role of epigenetics in sleep disorders
.
Mol Neurobiol
.
2018
;
55
:
2713
24
.
22.
Rusconi
F
,
Grillo
B
,
Ponzoni
L
,
Bassani
S
,
Toffolo
E
,
Paganini
L
,
LSD1 modulates stress-evoked transcription of immediate early genes and emotional behavior
.
Proc Natl Acad Sci U S A
.
2016
;
113
:
3651
6
. .
23.
Durack
J
,
Lynch
SV
.
The gut microbiome: relationships with disease and opportunities for therapy
.
J Exp Med
.
2019 Jan 7
;
216
(
1
):
20
40
. .
24.
Cryan
JF
,
O’Riordan
KJ
,
Cowan
CSM
,
Sandhu
KV
,
Bastiaanssen
TFS
,
Boehme
M
,
The microbiota-gut-brain axis
.
Physiol Rev
.
2019
;
99
:
1877
2013
. .
25.
Messaoudi
M
,
Lalonde
R
,
Violle
N
,
Javelot
H
,
Desor
D
,
Nejdi
A
,
Assessment of psychotropic-like properties of a probiotic formulation (Lactobacillus helveticus R0052 and Bifidobacterium longum R0175) in rats and human subjects
.
Br J Nutr
.
2011
;
105
:
755
64
. .
26.
Messaoudi
M
,
Violle
N
,
Bisson
JF
,
Desor
D
,
Javelot
H
,
Rougeot
C
.
Beneficial psychological effects of a probiotic formulation (Lactobacillus helveticus R0052 and Bifidobacterium longum R0175) in healthy human volunteers
.
Gut Microbes
.
2011
;
2
:
256
61
. .
27.
Takada
M
,
Nishida
K
,
Gondo
Y
,
Kikuchi-Hayakawa
H
,
Ishikawa
H
,
Suda
K
,
Beneficial effects of Lactobacillus casei strain Shirota on academic stress-induced sleep disturbance in healthy adults: a double-blind, randomised, placebo-controlled trial
.
Benef Microbes
.
2017
;
8
:
153
62
. .
28.
Marotta
A
,
Sarno
E
,
Del Casale
A
,
Pane
M
,
Mogna
L
,
Amoruso
A
,
Effects of probiotics on cognitive reactivity, mood, and sleep quality
.
Front Psychiatry
.
2019
;
10
:
164
. .
29.
Lew
LC
,
Hor
YY
,
Yusoff
NAA
,
Choi
SB
,
Yusoff
MSB
,
Roslan
NS
,
Probiotic Lactobacillus plantarum P8 alleviated stress and anxiety while enhancing memory and cognition in stressed adults: a randomised, double-blind, placebo-controlled study
.
Clin Nutr
.
2019
;
38
:
2053
64
. .
30.
Benton
D
,
Williams
C
,
Brown
A
.
Impact of consuming a milk drink containing a probiotic on mood and cognition
.
Eur J Clin Nutr
.
2007
;
61
:
355
61
. .
31.
Pinto-Sanchez
MI
,
Hall
GB
,
Ghajar
K
,
Nardelli
A
,
Bolino
C
,
Lau
JT
,
Probiotic Bifidobacterium longum NCC3001 reduces depression scores and alters brain activity: a pilot study in patients with irritable bowel syndrome
.
Gastroenterology
.
2017
;
153
:
448
59.e8
. .
32.
Sawada
D
,
Kawai
T
,
Nishida
K
,
Kuwano
Y
,
Fujiwara
S
,
Rokutan
K
.
Daily intake of Lactobacillus gasseri CP2305 improves mental, physical, and sleep quality among Japanese medical students enrolled in a cadaver dissection course
.
J Funct Foods
.
2017
;
31
:
188
97
. .
33.
Slykerman
RF
,
Hood
F
,
Wickens
K
,
Thompson
JMD
,
Barthow
C
,
Murphy
R
,
Effect of Lactobacillus rhamnosus HN001 in pregnancy on postpartum symptoms of depression and anxiety: a randomised double-blind placebo-controlled trial
.
EBioMedicine
.
2017
;
24
:
159
65
. .
34.
Chahwan
B
,
Kwan
S
,
Isik
A
,
van Hemert
S
,
Burke
C
,
Roberts
L
.
Gut feelings: a randomised, triple-blind, placebo-controlled trial of probiotics for depressive symptoms
.
J Affect Disord
.
2019
;
253
:
317
26
. .
35.
Chong
HX
,
Yusoff
NAA
,
Hor
YY
,
Lew
LC
,
Jaafar
MH
,
Choi
SB
,
Lactobacillus plantarum DR7 alleviates stress and anxiety in adults: a randomised, double-blind, placebo-controlled study
.
Benef Microbes
.
2019
;
10
:
355
73
. .
36.
Davidson
MG
.
Herbal-caffeinated chewing gum, but not bubble gum, improves aspects of memory
.
Appetite
.
2011
;
57
:
303
7
. .
37.
Laiacona
M
,
Inzaghi
MG
,
De Tanti
A
,
Capitani
E
.
Wisconsin card sorting test: a new global score, with Italian norms, and its relationship with the Weigl sorting test
.
Neurol Sci
.
2000
;
21
:
279
91
. .
38.
Zimmermann
P
,
Sprengelmeyer
R
,
Fimm
B
,
Wallesch
CW
.
Cognitive slowing in decision tasks in early and advanced Parkinson’s disease
.
Brain Cogn
.
1992 Jan
;
18
(
1
):
60
9
. .
39.
Spielberger
CD
,
Gorsuch
RL
.
State-trait anxiety inventory for adults: manual and sample: manual, instrument and scoring guide
.
Palo Alto
:
Consulting Psychologists Press
;
1983
.
40.
Soldatos
CR
,
Dikeos
DG
,
Paparrigopoulos
TJ
.
Athens Insomnia Scale: validation of an instrument based on ICD-10 criteria
.
J Psychosom Res
.
2000
;
48
:
555
60
. .
41.
Qi
M
,
Gao
H
,
Guan
L
,
Liu
G
,
Yang
J
.
Subjective stress, salivary cortisol, and electrophysiological responses to psychological stress
.
Front Psychol
.
2016
;
7
:
229
. .
42.
Liu
JC
,
Verhulst
S
,
Massar
SA
,
Chee
MW
.
Sleep deprived and sweating it out: the effects of total sleep deprivation on skin conductance reactivity to psychosocial stress
.
Sleep
.
2015
;
38
:
155
9
. .
43.
Lykken
DT
,
Venables
PH
.
Direct measurement of skin conductance: a proposal for standardization
.
Psychophysiology
.
1971
;
8
:
656
72
. .
44.
Provensi
G
,
Schmidt
SD
,
Boehme
M
,
Bastiaanssen
TFS
,
Rani
B
,
Costa
A
,
Preventing adolescent stress-induced cognitive and microbiome changes by diet
.
Proc Natl Acad Sci U S A
.
2019
;
116
:
9644
51
. .
45.
Partrick
KA
,
Chassaing
B
,
Beach
LQ
,
McCann
KE
,
Gewirtz
AT
,
Huhman
KL
.
Acute and repeated exposure to social stress reduces gut microbiota diversity in Syrian hamsters
.
Behav Brain Res
.
2018
;
345
:
39
48
. .
46.
Gur
TL
,
Bailey
MT
.
Effects of stress on commensal microbes and immune system activity
.
Adv Exp Med Biol
.
2016
;
874
:
289
300
. .
47.
Gagliardi
A
,
Totino
V
,
Cacciotti
F
,
Iebba
V
,
Neroni
B
,
Bonfiglio
G
,
Rebuilding the gut microbiota ecosystem
.
Int J Environ Res Public Health
.
2018
;
15
:
1679
. .
48.
Sarkar
A
,
Lehto
SM
,
Harty
S
,
Dinan
TG
,
Cryan
JF
,
Burnet
PWJ
.
Psychobiotics and the manipulation of bacteria-gut-brain signals
.
Trends Neurosci
.
2016
;
39
:
763
81
. .
49.
Dinan
TG
,
Cryan
JF
.
Mood by microbe: towards clinical translation
.
Genome Med
.
2016
;
8
:
36
. .
50.
Mohajeri
MH
,
La Fata
G
,
Steinert
RE
,
Weber
P
.
Relationship between the gut microbiome and brain function
.
Nutr Rev
.
2018
;
76
:
481
96
. .
51.
Bourassa
MW
,
Alim
I
,
Bultman
SJ
,
Ratan
RR
.
Butyrate, neuroepigenetics and the gut microbiome: can a high fiber diet improve brain health?
Neurosci Lett
.
2016
;
625
:
56
63
. .
52.
Liang
S
,
Wang
T
,
Hu
X
,
Luo
J
,
Li
W
,
Wu
X
,
Administration of Lactobacillus helveticus NS8 improves behavioral, cognitive, and biochemical aberrations caused by chronic restraint stress
.
Neuroscience
.
2015
;
310
:
561
77
. .
53.
Borrelli
L
,
Aceto
S
,
Agnisola
C
,
De Paolo
S
,
Dipineto
L
,
Stilling
RM
,
Probiotic modulation of the microbiota-gut-brain axis and behaviour in zebrafish
.
Sci Rep
.
2016
;
6
:
30046
. .
54.
Das
D
,
Goyal
A
.
Antioxidant activity and γ-aminobutyric acid (GABA) producing ability of probiotic Lactobacillus plantarum DM5 isolated from Marcha of Sikkim
.
LWT-Food Sci Technol
.
2015
;
61
:
263
8
.
55.
Boricha
AA
,
Shekh
SL
,
Pithva
SP
,
Ambalam
PS
,
Manuel Vyas
BR
.
In vitro evaluation of probiotic properties of Lactobacillus species of food and human origin
.
LWT
.
2019
;
106
:
201
8
. .
56.
Mancini
A
,
Carafa
I
,
Franciosi
E
,
Nardin
T
,
Bottari
B
,
Larcher
R
,
In vitro probiotic characterization of high GABA producing strain Lactobacilluas brevis DSM 32386 isolated from traditional “wild” Alpine cheese
.
Ann Microbiol
.
2019
;
69
(
13
):
1435
43
. .
57.
Kochalska
K
,
Oakden
W
,
Słowik
T
,
Chudzik
A
,
Pankowska
A
,
Łazorczyk
A
,
Dietary supplementation with Lactobacillus rhamnosus JB-1 restores brain neurochemical balance and mitigates the progression of mood disorder in a rat model of chronic unpredictable mild stress
.
Nutr Res
.
2020
;
82
:
44
57
. .
58.
Yunes
RA
,
Poluektova
EU
,
Vasileva
EV
,
Odorskaya
MV
,
Marsova
MV
,
Kovalev
GI
,
A multi-strain potential probiotic formulation of GABA-producing Lactobacillus plantarum 90sk and Bifidobacterium adolescentis 150 with antidepressant effects
.
Probiotics Antimicrob Proteins
.
2020
;
12
:
973
9
. .
59.
Borrelli
E
,
Nestler
EJ
,
Allis
CD
,
Sassone-Corsi
P
.
Decoding the epigenetic language of neuronal plasticity
.
Neuron
.
2008 Dec 26
;
60
(
6
):
961
74
. .
60.
Israelyan
N
,
Margolis
KG
.
Serotonin as a link between the gut-brain-microbiome axis in autism spectrum disorders
.
Pharmacol Res
.
2018
;
132
:
1
6
. .
61.
O’Mahony
SM
,
Clarke
G
,
Borre
YE
,
Dinan
TG
,
Cryan
JF
.
Serotonin, tryptophan metabolism and the brain-gut-microbiome axis
.
Behav Brain Res
.
2015
;
277
:
32
48
. .
62.
Özogul
F
.
Effects of specific lactic acid bacteria species on biogenic amine production by foodborne pathogen
.
Int J Food Sci Technol
.
2011
;
46
(
3
):
478
84
. .
63.
Shishov
VA
,
Kirovskaia
TA
,
Kudrin
VS
,
Oleskin
AV
.
[Amine neuromediators, their precursors, and oxidation products in the culture of Escherichia coli K-12]
.
Prikl Biokhim Mikrobiol
.
2009
;
45
:
550
4
.
64.
Wikoff
WR
,
Anfora
AT
,
Liu
J
,
Schultz
PG
,
Lesley
SA
,
Peters
EC
,
Metabolomics analysis reveals large effects of gut microflora on mammalian blood metabolites
.
Proc Natl Acad Sci U S A
.
2009
;
106
:
3698
703
. .
65.
Hellhammer
DH
,
Wüst
S
,
Kudielka
BM
.
Salivary cortisol as a biomarker in stress research
.
Psychoneuroendocrinology
.
2009
;
34
:
163
71
. .
66.
Lin
HP
,
Lin
HY
,
Lin
WL
,
Huang
AC
.
Effects of stress, depression, and their interaction on heart rate, skin conductance, finger temperature, and respiratory rate: sympathetic-parasympathetic hypothesis of stress and depression
.
J Clin Psychol
.
2011
;
67
:
1080
91
.
67.
Sawada
D
,
Kawai
T
,
Nishida
K
,
Kuwano
Y
,
Fujiwara
S
,
Rokutan
K
.
Daily intake of Lactobacillus gasseri CP2305 improves mental, physical, and sleep quality among Japanese medical students enrolled in a cadaver dissection course
.
J Funct Foods
.
2017
;
31
:
188
97
. .
68.
Jackson
ML
,
Butt
H
,
Ball
M
,
Lewis
DP
,
Bruck
D
.
Sleep quality and the treatment of intestinal microbiota imbalance in Chronic Fatigue Syndrome: a pilot study
.
Sleep Sci
.
2015
;
8
:
124
33
. .
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