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The Use of Cannabinoids in Colitis: A Systematic Review and Meta-Analysis


Abstract and Figures

Background Clinical trials investigating the use of cannabinoid drugs for the treatment of intestinal inflammation are anticipated secondary to preclinical literature demonstrating efficacy in reducing inflammation. Methods We systematically reviewed publications on the benefit of drugs targeting the endo-cannabinoid system in intestinal inflammation. We collated studies examining outcomes for meta-analysis from EMBASE, MEDLINE and Pubmed until March 2017. Quality was assessed according to mSTAIR and SRYCLE score. Results From 2008 papers, 51 publications examining the effect of cannabinoid compounds on murine colitis and 2 clinical studies were identified. Twenty-four compounds were assessed across 71 endpoints. Cannabidiol, a phytocannabinoid, was the most investigated drug. Macroscopic colitis severity (disease activity index [DAI]) and myeloperoxidase activity (MPO) were assessed throughout publications and were meta-analyzed using random effects models. Cannabinoids reduced DAI in comparison with the vehicle (standard mean difference [SMD] -1.36; 95% CI, -1.62 to-1.09; I² = 61%). FAAH inhibitor URB597 had the largest effect size (SMD -4.43; 95% CI, -6.32 to -2.55), followed by the synthetic drug AM1241 (SMD -3.11; 95% CI, -5.01 to -1.22) and the endocannabinoid anandamide (SMD -3.03; 95% CI, -4.89 to -1.17; I² not assessed). Cannabinoids reduced MPO in rodents compared to the vehicle; SMD -1.26; 95% CI, -1.54 to -0.97; I² = 48.1%. Cannabigerol had the largest effect size (SMD -6.20; 95% CI, -9.90 to -2.50), followed by the synthetic CB1 agonist ACEA (SMD -3.15; 95% CI, -4.75 to -1.55) and synthetic CB1/2 agonist WIN55,212-2 (SMD -1.74; 95% CI, -2.81 to -0.67; I² = 57%). We found no evidence of reporting bias. No significant difference was found between the prophylactic and therapeutic use of cannabinoid drugs. Conclusions There is abundant preclinical literature demonstrating the anti-inflammatory effects of cannabinoid drugs in inflammation of the gut. Larger randomised controlled-trials are warranted.
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Inflamm Bowel Dis
• Volume 24, Number 4, April 2018
Review ARticle BAsic science
The Use of Cannabinoids in Colitis: A Systematic Review and
Daniel G.Couch,* HenryMaudslay, BrettDoleman, PhD, Jonathan N.Lund, PhD, and
Saoirse E.O’Sullivan, PhD
Background: Clinical trials investigating the use of cannabinoid drugs for the treatment of intestinal inammation are anticipated secondary to
preclinical literature demonstrating efcacy in reducing inammation.
Methods: We systematically reviewed publications on the benet of drugs targeting the endo-cannabinoid system in intestinal inammation.
We collated studies examining outcomes for meta-analysis from EMBASE, MEDLINE and Pubmed until March 2017. Quality was assessed
according to mSTAIR and SRYCLE score.
Results: From 2008 papers, 51 publications examining the effect of cannabinoid compounds on murine colitis and 2 clinical studies were identi-
ed. Twenty-four compounds were assessed across 71 endpoints. Cannabidiol, a phytocannabinoid, was the most investigated drug. Macroscopic
colitis severity (disease activity index [DAI]) and myeloperoxidase activity (MPO) were assessed throughout publications and were meta-ana-
lyzed using random effects models. Cannabinoids reduced DAI in comparison with the vehicle (standard mean difference [SMD] -1.36; 95%
CI, -1.62 to-1.09; I2=61%). FAAH inhibitor URB597 had the largest effect size (SMD -4.43; 95% CI, -6.32 to -2.55), followed by the synthetic
drug AM1241 (SMD -3.11; 95% CI, -5.01 to -1.22) and the endocannabinoid anandamide (SMD -3.03; 95% CI, -4.89 to -1.17; I2 not assessed).
Cannabinoids reduced MPO in rodents compared to the vehicle; SMD -1.26; 95% CI, -1.54 to -0.97; I2=48.1%. Cannabigerol had the largest
effect size (SMD -6.20; 95% CI, -9.90 to -2.50), followed by the synthetic CB1 agonist ACEA (SMD -3.15; 95% CI, -4.75 to -1.55) and synthetic
CB1/2 agonist WIN55,212-2 (SMD -1.74; 95% CI, -2.81 to -0.67; I2=57%). We found no evidence of reporting bias. No signicant difference was
found between the prophylactic and therapeutic use of cannabinoid drugs.
Conclusions: There is abundant preclinical literature demonstrating the anti-inammatory effects of cannabinoid drugs in inammation of the
gut. Larger randomised controlled-trials are warranted.
Key words: cannabinoid, inflammation, gut, intestine, colitis
Inammatory bowel disease (IBD) affects 200 per
100,000 adults in the United States and 400 per 100,000 in the
United Kingdom.1, 2 Major subtypes consist of Crohn’s dis-
ease and ulcerative colitis. A denitive clinical treatment for
these chronic relapsing diseases remains elusive, as currently
no therapy exists to reverse the clinical pathology without a
risk of signicant side effects. Corticosteroids, 5-ASA agents,
anti-TNFα antibodies, and other immunomodulatory drugs
have all been shown to induce signicant remission in IBD,
but are associated with bone marrow suppression, opportunis-
tic infection, infusion reactions, and malignancy secondary to
The endocannabinoid system (ECS), consisting of mul-
tiple receptors and endogenous ligands, controls multiple
homeostatic processes including gastrointestinal motility, hun-
ger, perception of pain, and immunity.6–10 The targets of the
ECS consist of the classical CB1 and CB2 receptors, but also
the orphan GPR55 receptor, peroxisome proliferator-activated
receptors (PPARs), and transient receptor potential vanilloid
(TRPV) receptors. These targets are all found on the cells of
gut mucosa, submucosa, the enteric nervous system and the
immune system. Endocannabinoids, such as anandamide
(AEA) and 2-arachiodoylglycerol (2-AG), are intercellular
Received for publications October 12, 2017; Editorial Decision November 27,
School of Medicine, Royal Derby Hospital, University of Nottingham, Derby,
DE22 3DT United Kingdom.
© 2018 Crohn’s & Colitis Foundation. Published by Oxford University Press
on behalf of Crohn’s & Colitis Foundation.
Author Contributions:
DC, JL, and SO conceived and designed the study. DC and HM collected data.
DC, HM, BD, JL, and SO analyzed data. DC, JL, and SO were responsible for over-
all content of the article.
All authors drafted, revised, and approved the manuscript. The authors have no
conicts of interest to report. No funding was recived for this study.
*Address correspondence to: Daniel G.Couch, MB, ChB, School of Medicine,
Royal Derby Hospital, University of Nottingham, Derby. DE22 3DT United
Kingodm . E-mail:
Abbreviations: 2-AG, 2-arachidonoyl glycerol; Ab-CBD, Abnormal can-
nabidiol; AEA, Anandamide; CBD, Cannabidiol; CBG, Cannabigerol; CBN,
Cannabinol; CI, Condence interval; CO, Croton oil; DAI, Disease activity
index; DNBS, Dinitrobenzene sulphonic acid; DSS, Dextran sulphate sodium; IC,
Intracolonic; IL-10, Interleukin-10; IV, Intravenous; MMJ, Medicinal cannabis;
MPO, Myeloperoxidase; OM, Oil of mustard; PEA, Palmitoylethanolamide; PO,
Oral; PPAR, Peroxisome Proliferator Activating Receptor; PR, Per rectum; SC,
Subcutaneous; SMD, Standard mean difference; THC, Δ9-Tetrahydrocannabinol;
TNBS, Trinitrobenzene sulphonic acid; TRPV1, Transient receptor potential vanil-
loid 1
doi: 10.1093/ibd/izy014
Published online 19 March 2018
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Volume 24, Number 4, April 2018 The use of cannabinoids in colitis: a systematic review and meta-analysis
lipid-signalling molecules derived on demand from membrane
precursors.11 They are metabolised by fatty acid amide hydro-
lase (FAAH), as well as N-acyl ethanolamine-hydrolysing acid
amidase (NAAA) in the case of AEA, and monoacylglycerol
lipase (MAGL) in the case of 2-AG.12–14 Palmitoylethanolamide
(PEA), also metabolised by NAAA, has been shown to activate
PPARα and may increase local concentrations of AEA or the
afnity of AEA to the CB1 receptor and, therefore, is included
as an atypical cannabinoid.15, 16 Phytocannabinoids include Δ-9
tetrahydrocannabinol (THC), cannabidiol (CBD), cannab-
igerol (CBG), cannibichromene (CBC), and up to 60 others and
are isolated from Cannabis Sativa.11 THC and CBD have found
place in clinical practice in the treatment of childhood epilepsy
and muscular spasticity in multiple sclerosis.17, 18 A growing
collection of synthetic cannabinoid agonists have been derived
possessing selective high afnity for the CB1, CB2, GPR55 and
TRPV1 receptors, and have been investigated pre-clinically for
roles in gut motility, satiety and immunity.8
Under inammatory conditions CB1, CB2, and both
PPARα and PPARγ expressions increase on the submucosa
and on adjacent immune cells, whereas GPR55 and TRPV1
expression decreases on the mucosa, but increases on enteric
nervous tissue.19–21 Levels of AEA, 2-AG, and PEA are upreg-
ulated in vitro, and also in animal in vivo and human ex-vivo
models of intestinal inammation.22–24 Early experimentation
in murine models demonstrated that cannabinoids prevent the
onset of experimental murine colitis or reduced its severity.25
Since these initial ndings, many reports—including clinical tri-
als—have now investigated the effect of cannabinoid ligands, or
the effect of blockade of their metabolising enzymes, on inam-
mation of thegut.
There is a signicant amount of promising preclinical
evidence for the use of cannabinoid agents in the treatment of
colitis. Within this study we aimed to gather all preclinical and
clinical evidence for the use of these drugs in colitis, and where
possible, perform meta-analyses across studies to assess the ef-
cacy of cannabinoids for further clinical trials. Where possible,
clinically relevant experimental endpoints were assessed.
Search Strategy
All studies evaluating the effect of cannabinoid drugs
on inammation of the colon were searched from March
1980 to March 2017 by 2 independent researchers in Medline,
EMBASE, and Pubmed. Keywords included cannabidiol, tet-
rahydrocannabinol, anandamide, 2-AG, cannibichromene, can-
nabigerol, cannabinoid, cannabis sativa, colon, intestine, gut,
inammation, Crohns, ulcerative, and colitis. Names of syn-
thetic cannabinoid agents were also included. References from
included studies were searched by hand. Prespecied inclusion
and exclusion criteria were used to prevent bias. Experiments
must have been performed in the context of administration
of cannabinoid drugs to inammatory states of the colon in
humans or animals, either experimental or due to endogenous
disease (Crohn’s disease or ulcerative colitis). In vitro studies,
studies not examining the effect of cannabinoids in intestinal
inammation specically, or studies using cannabinoid antago-
nists as a primary agent were excluded. APRISMA checklist is
included in the appendix.
Data Acquisition
The mode of colitis induction in preclinical studies was
recorded in addition to the timing of cannabinoid application.
For the purposes of meta-analysis, data on the macroscopic or
histological disease scores (as listed in the disease activity index
[DAI]) and myeloperoxidase (MPO) activity were collected. If
the exact number of animals was not available, the lowest num-
ber of animals within the range given was used for the experi-
mental group, and the highest number used for the control/
vehicle group. Where studies reported the effects of more than
1 cannabinoid sharing a single control group for comparison,
control group numbers were equally distributed between com-
parisons to avoid unit of analysis issues. WebPlotDigitiser (ver-
sion 3.11) was used to extract values from gures in published
articles where no data values were given in the text.
Quality of included studies were assessed by 2 independ-
ent researchers to quantify risk of bias according to the 6-point
criteria developed by the Cochrane Collaboration risk of bias
tool.26 To assess the quality of preclinical studies, the STAIR
and Arrive preclinical assessment tools were adapted.27, 28 Each
of these items was awarded 1 point: randomization, assessor
blinding, results replicated in a second species, dose-response
experiments, results replicated in a second model of colitis,
n=5 or greater in each group, the use of clinically relevant end-
point to assess response of colitis, a denitive statement of ani-
mal numbers in each group, a statement regarding the housing
of animals, and a statement describing the location and timing
of animal experimentation (i.e. in animal housing or a separate
cage, time of day etc). The highest possible score was 10 points.
Data Analysis
Where possible, data were grouped into DAI and MPO
activity, and subdivided by species and compound. Data from
each group were analysed as forest plots using Cochrane Review
Manager Software (Review Manager 5.3, Copenhagen: The
Nordic Cochrane Centre, The Cochrane Collaboration, 2014),
and as funnel plots using Stat (Stat Corp.2009 Stat Statistical
Software: Release 11. College Station, TX, USA). Funnel plot
asymmetry was tested using the Egger linear regression test.
AP value of <0.05 was considered statistically signicant. As
differing studies measured MPO activity and DAI using var-
ious scales, we present effect estimates as standardized mean
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Couch etal
differences (SMD) with 95% condence intervals (CI). We used
the following SMD values to assess results for clinical signif-
icance: <-0.5 small clinical signicance, -0.5 to -0.8 moderate
clinical signicance, and >-0.8 high clinical signicance. Due to
clinical heterogeneity between the various studies, a random-ef-
fects model was used. We assessed statistical heterogeneity
using the I2 statistic, with >50% regarded as evidence of statis-
tical heterogeneity. We assessed the quality of evidence using
the previously validated SYRCLE criteria, with studies graded
out of 10.29 Studies were weighted by sample size and statistical
signicance was set at a minimum of P<0.05.
Search Results and Study Characteristics
The search strategy returned 2008 results from which 199
relevant publications were identied. From these, 53 publica-
tions comprising 106 experiments examining 35 compounds
met the inclusion criteria (Fig.1, Tables 1 and 2). Thirty-four
studies were included in the meta-analysis.
Forty-three publications studied the effects of cannabi-
noids on experimental murine colitis, 5 in rats, and 3 in both
mice and rats. Two clinical trials examined the effect of a can-
nabinoid (THC and CBD) in Crohn’s disease. Within animal
publications, 43 used caustic agents (Di-nitrobenzine sulphonic
acid (DNBS), trinitrobenzene sulphonic acid (TNBS), oil of
mustard (OM), dextran sulphate sodium (DSS), and croton oil
(CO)) to induce colitis; 6 used intravenous or topical lipopol-
ysaccharide; 2 induced colonic inammation using surgical
arterial ligation or puncture of the colon; and 1 induced colitis
with interleukin-10 (IL-10) knock-down and DSS (Fig. 2A).
Across all publications, including clinical trials, 71 endpoints
were examined to evaluate the effect of cannabinoid drugs
on colitis. Forty-nine publications (89 experiments) examined
more than 1 endpoint. Of these endpoints, MPO and DAI were
the most consistently used (34 and 26 studies, respectively) and
were therefore selected for meta-analysis. Incidence of end-
points is given in Fig.2B.
The effect of 7 phytocannabinoids were studied across
18 publications; cannabinol (CBN), CBD, THC, CBC, CBG,
medicinal cannabis (MMJ), and abnormal CBD (Ab-CBD).
Four endocannabinoids were studied across 11 publica-
tions (PEA, ultramicronized PEA [uPEA], Arachidonyl-
2’-chloroethylamide [ACEA], and AEA); 15 synthetic
cannabinoid agonists were studied across 22 publications
(AM841, Adelmidrol, HU210, CP55940, WIN55,212-2,
AM1241, JHW015, JWH133, βCaryophyllene, O-1602,
HU308, αβ amyrin, CID16020046, compound 26, and
SAB378); and 9 compounds targeting the catabolism or trans-
port of endogenous cannabinoids were studied across 13 publi-
cations (ARN2508, PF-3845, compound 39, JZL184, AA5HT,
VDM11, URB597, AM9053, and AM3506). These compounds
are delineated by classin Table1. The degrees of positivity or
negativity of the outcomes of these studies are displayed in
Fig. 2C. Twenty-three studies investigated underlying recep-
tor mechanisms using knock-out (KO) animals or receptor
Of the 105 experiments comparing cannabinoids with the
vehicle or placebo, 67 (63.8%) favored cannabinoids, 34 (32.3%)
reported no difference, and 4 (3.8%) favored vehicle. Mice were
used in 89 experiments (68.5% of which favored cannabinoids),
while rats were used in 14 (71.4% favored cannabinoids). In 4
experiments, both mice and rats were used showing no differ-
ence between cannabinoids and the vehicle. In the 2 clinical
trials, no difference in primary outcome was found between
the use of THC cigarettes or oral CBD and placebo. Eleven
of 14 publications (78.6%) using synthetic CB2 receptor ago-
nists favored cannabinoid use over the vehicle, and a further 11
of 13 (84.6%) favored using FAAH inhibitors over the vehicle.
The outcome of all cannabinoids across publications is given
in Fig.2C.
Two clinical trials examining the effect of CBD and THC
in Crohn’s disease were found. Naftali etal (2013) conducted a
placebo-controlled study in Crohn’s disease patients, comparing
THC 115mg inhaled alone with placebo. Disease activity was
compared between groups by means of a validated question-
naire (Crohn’s disease activity index [CDAI]) after 8 weeks of
treatment. Anonsignicant reduction in clinical disease remis-
sion as dened by the authors was found at the end of the study
period; however, a secondary endpoint of reduction in overall
activity scores was found between groups (P=0.028). In a sec-
ond study, Naftali et al (2017) compared 10 mg of oral CBD
twice daily with placebo in Crohn’s disease, using CDAI in an
identical fashion. No reduction in disease activity was detected
Figure1. Record identication process.
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Volume 24, Number 4, April 2018 The use of cannabinoids in colitis: a systematic review and meta-analysis
between groups. In both studies, the authors measured changes
in serum C-reactive protein (CRP). Within both experimental
and placebo groups, CRP levels were below 5 units per milliliter
at the end of the study periods. Clinically, CRP levels greater
than 5 units per milliliter are considered indicative of inam-
matory disease. Within both studies, the combination of CBD
and THC within a single study were not assessed.
Of the 104 experiments where timing of drug administra-
tion was stated, 37 administered cannabinoids therapeutically,
of which 62.2% favored cannabinoid treatment. Nineteen experi-
ments administered cannabinoids prophylactically, of which 52.6%
favored cannabinoid treatment. Forty-eight experiments adminis-
tered cannabinoids both prophylactically and therapeutically, of
which 75% favored cannabinoid treatment versus the vehicle.
Thirty-four studies reported the same endpoints of dis-
ease activity index or myeloperoxidase activity, allowing for
meta-analysis. Of the remaining studies, heterogeneity of end-
points prevented further meta-analysis.
Crohn’s Disease Activity Index(CDAI)
The use of 2 phytocannabinoids, THC or CBD, in 2
human studies were meta-analysed. Phytocannabinoid use
decreased severity scores in comparison with placebo (mean
difference [MD] -74.97; 95% CI, -229 to 0.79, I2=75% Fig.3).
THC alone had a signicant effect on reducing CDAI (MD
-154.00; 95% CI, -2.68.57 to -44.43), whereas CBD alone did
not (MD +4.00;, 95% CI -1.5.39 to +113.39).
TABLE1: Cannabinoid Drugs Found by Search Strategy
Cannabinoid Class Drug Description
Endocannabinoids AEA Anandamide
PEA Palmitoylethanolamide
uPEA Ultramicronised PEA
Phytocannabinoids Cannabis sativa Multiple compounds
CBC Cannibichromene
CBD Cannabidiol
CBG Cannabigerol
CBN Cannabinol
THC Tetrahydrocannabinol
Cannabinomimetics αβ Amyrin CB1 and CB2 agonist
ACEA Arachidonyl-2’-chloroethylamide
Adelmidrol PEA analogue
AM1241 CB2 full agonist, partial CB1 agonist
AM841 Peripherally restricted CB1 agonist
βCaryophyllene CB2 agonist
CID16020046 GPR55 inverse agonist
Compound 26 CB2 agonist
CP55,940 CB1 and CB2 agonist
HU210 THC analogue
HU308 CB2 agonist
JWH015 CB2 full agonist, weak CB1 agonist
JHW133 CB2 full agonist, weak CB1 agonist
O-1602 GPR18 and GPR55 agonist
SAB378 Peripherally restricted CB1 and CB2 agonist
WIN55,212-2 CB1 full agonist
Enzyme Inhibitors AA5HT FAAH inhibitor
AM3506 FAAH inhibitor
AM9053 NAAA inhibitor
ARN2508 FAAH inhibitor
compound 39 FAAH inhibitor
JZL184 MAGL inhibitor
PF-3845 FAAH inhibitor
URB597 FAAH inhibitor
Reuptake inhibitors VDM11 AEA reuptake inhibitor
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Couch etal
(Continued )
TABLE2: Characteristics of Studies Included for Systematic Review
Study Species Model Compound Route/dosage
Time of Administration
Versus Inammation
Time of
Assessment Post
Modied STAIR
score SRCYCLE Score
Capasso 200132 ICR mice CO PEA i.p 2.5–30mg/kg 20 minutes pre 4days 4 1
Izzo 20019ICR mice CO CP 55,940
i.p.0.03–10nmol/m 4days post 20 minutes 3 0
Massa 200425 C57BL/6N mice DNBS SR141716 i.p.3mg/kg Pre, 24 and 48 hours post 3& 7days 4 2
HU210 i.p.0.05mg/kg
Mathison 200450 Spr-Dawley rats LPS ACEA i.p.1mg/kg 70 minutes post 120 minutes 5 0
JWH133 i.p.1mg/kg
D’Argenio 200622 C57/BJ mice
Wistar rats
DNBS VDM11 SC 5mg/kg Post 3& 7days 6 0
TNBS AA-5-HT SC 10mg/kg
Kimball 200651 CD-1 mice OM ACEA i.p.10mg/kg 24 hours pre 3days 3 1
JWH133 i.p.2.5mg/kg
Capasso 200852 ICR mice CO CBD i.p.5mg/kg 20 minutes pre Ach 4days 5 0
JWH015 i.p.10mg/kg
Engel 200853 AKR mice TNBS AEA i.p.5mg/kg 30 minutes pre 3days 3 1
Storr 200854 C57/BL mice TNBS URB597 i.p.5mg/kg 30 minutes pre or 24 hours
3days 4 1
VDM11 i.p.5mg/kg
Borelli 200946 ICR mice DNBS CBD i.p.1, 2, 5, 10mg/kg 24 hours post 3days 3 0
Li 200955 Rats Mice LPS HU210 100μ 5 minutes 30 minutes 8 1
AM630 100μ
AM251 3mg/kg
Storr 200956 C57/BL mice TNBS JWH133 i.p.20mg/kg 30 minutes pre or 24 hours
1, 3, 5, 7days 7 1
DSS AM1241 i.p.10–20mg/kg
AM630 i.p.10mg/kg
Cassol Jr 201047 Wistar rats CLP CBD i.p.2.5, 4, 10mg/kg Simultaneous 9days 8 2
Cluny 201057 C57/BL mice DSS SAB378 i.p 0.1 or 1.0mg/kg 4days post 8days 5 1
TNBS AM251 i.p 1.0mg/kg
AM630 i.p 1.0mg/kg
WIN55,212-2 i.p 1, 2mg/kg
Kimball 201058 CD1 mice OM ACEA i.p.1mg/kg 30 minutes pre 28days 4 3
Jamontt 201045 Wistar rats TNBS THC i.p.5–20mg/kg 30 minutes pre 3days 5 1
Alhouayek 201159 C57BL/6 mice TNBS JZL184 i.p.16mg/kg Pre onset 3days 2 1
Andrejak 201160 C57/BL mice TNBS Compound 39 i.p.5mg/kg 3days pre 3days 6 1
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Study Species Model Compound Route/dosage
Time of Administration
Versus Inammation
Time of
Assessment Post
Modied STAIR
score SRCYCLE Score
Bento 201161 CD1 mice DSS βCaryophyllene i.p.12.5, 25, 50mg/kg 3 -7days post 7days 4 1
Delipis 201149 OF1 mice LPS CBD i.p.10mg/kg 6 hours post 120 minutes 6 1
Lin 201143 C57/BL mice LPS CBD O-1602 i.p.10mg/kg 30 minutes pre 20 minutes 5 1
Spr-Dawley rats I.p.1mg/kg
Schicho 201162 C57/BL mice DSS O-1602 i.p.5mg/kg 30 minutes pre 7days 3 3
Bashashati 201263 CD1 mice LPS AM3506 i.p.100 20 minutes pre 120 minutes 3 0
Izzo 201264 ICR mice CO CBC i.p.15mg/kg 20 minutes pre exam 4days 5 2
Lehmann 201265 Lewis rats LPS HU308 2.5mg/kg 15 minutes post 2–16 hours 4 0
Schicho 201242 C57/BL mice TNBS CBD i.p.10mg/kg 30 minutes pre onset 7days 4 0
PO 20mg/kg
PR 20mg/kg
Singh 201266 C57/BL mice IL-10 -/-DSS JWH133 i.p.2.5mg/kg Simultaneous 7–14days 5 1
Borrelli 201367 ICR mice DNBS CBG i.p.30mg/kg 3days pre 3days 5 1
Esposito 201433 CD-1 mice DSS PEA i.p.10mg/kg 2days post 7days 5 2
Li 201368 C57/BL mice DSS WIN55,212-2 i.p.5mg/kg Simultaneous 7days 4 1
Matos 201369 CD1 mice DSS αβ Amyrin PO 1, 3, 10mg/kg Pre and 3days post 7days 6 1
Naftali 201370 Clinical trial Crohn’s Cannabis sativa
extract (THC)
115mg inhaled N/A 8 weeks NA NA
Romano 201371 ICR mice DNBS CBC i.p 0.1–1.0mg/kg 24 hours post 3days 6 0
Wallace 201372 Wistar rats DNBS C.sativa (MMJ) IC 6mg/kg 30 minutes pre and 24
hours post
7days 4 1
AM630 PO 10mg/kg
Borelli 201573 ICR mice DNBS PEA i.p 1mg/kg 3days pre 3days 5 1
PO 1mg/kg
Capasso 201420 ICR mice OM PEA i.p.10mg/kg 30 minutes 3 and 7days 6 2
Fichna 201474 CD1 mice DSS AM841 i.p.0.01, 0.1,1mg/kg 15 minutes pre 3 and 7days 4 0
DNBS CB13 i.p.0.1mg/kg
Salaga 201475 C57/BL mice TNBS PF3845 i.p.10mg/kg 30 minutes 3 and 7days 2 0
DSS PO 5mg/kg
IC 5mg/kg
Sardinha 201476 C57/BL mice LPS HU308 IV 2.5mg/kg 15 minutes pre Simultaneous 6 0
AM630 IV 2.5mg/kg
URB597 i.p.0.6mg/kg
JZL184 i.p.16mg/kg
Alhouayek 201577 CD57/BL mice TNBS PEA i.p.10mg/kg Simultaneous and 5days
7days 4 1
DSS PF-3845 i.p.10mg/kg
AM9503 i.p.10mg/kg
TABLE2: Continued
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Couch etal
Study Species Model Compound Route/dosage
Time of Administration
Versus Inammation
Time of
Assessment Post
Modied STAIR
score SRCYCLE Score
El bakali 201578 C57/BL mice TNBS Compound 26 PO 10mg/kg 2days pre 7days 6 0
CD1 mice DNBS uPEA i.p.10mg/kg 1 hour post 4days 9 2
Sasso 201580 CD1 mice TNBS ARN2508 PO 5mg/kg Simultaneous 7days 8 3
Stančić 201581 C57/BL mice DSS CID16020046 SC 20mg/kg 30 minutes 7days 6 1
Cordaro 201682 CD1 mice DNBS Adelmidrol PO 10mg/kg 60 minutes post 4days 4 1
Feng 201683 C57/BL mice DSS WIN55,212-2 i.p.5mg/kg Simultaneous and 60
hours post
7days 5 1
Ke 201684 C57/BL mice DSS HU308 i.p.1mg/kg Simultaneous and daily 8days 4 2
Krohn 201640 CD1 mice TNBS Ab-CBD i.p.5mg/kg 45 minutes pre 4days 6 1
O-1918 i.p.5mg/kg
AM251 i.p.5mg/kg
AM630 i.p.5mg/kg
Pagano 201639 ICR mice DNBS CBD i.p.30mg/kg 24 hours post 3days 3 0
Pure CBD
CO PO 60mg/kg
Sarnelli 201685 CD1 mice DSS PEA i.p.2, 10mg/kg 2days post 7days 6 1
Lin 201786 C57/BL mice DSS HU210 i.p.0.05mg/kg 30 minutes pre 7days 5 1
Shamran 201787 C57/BL mice DSS FAAH-II i.p.5–40mg/kg 24 hours post 7days 6 1
Naftali 201735 Clinical trial Crohn’s CBD 10mg PO BD N/A 8 weeks NA NA
TABLE2: Continued
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Inflamm Bowel Dis
Volume 24, Number 4, April 2018 The use of cannabinoids in colitis: a systematic review and meta-analysis
Disease Activity Index(DAI)
Thirty-four publications examined the effects of 25 canna-
binoid drugs across 68 experiments, within mouse and rat models
(total n= 948; n = 519 experimental vs 429 in control groups).
Cannabinoid drugs reduced DAI in comparison with the vehicle;
SMD -1.36; 95% CI, -1.62 to -1.09; I2=61% (Fig.4, Table 3).
On subgroup analysis, there was a signicant difference between
drug subtypes (P<0.001). DAI was signicantly reduced in mice
(SMD -1.49; 95% CI, -1.77 to -1.22; I2=61%). Seven experiments
within one publication examined the effects of cannabinoids on
rat colitis (THC and CBD, both conducted in a dose response
manner), but did not reach signicance at any concentration
(SMD -0.29; 95% CI, -0.77 to 0.20; I2=0%). SMD and con-
dence intervals for individual drugs on DAI are given in Table3.
FIGURE2. Positive, negative, and neutral outcomes of cannabinoid treatment across modes of inammation (A). Incidence of endpoints across
all experiments comparing cannabinoid treatment with control (B). The eect of cannabinoid drugs compared with control across all endpoints
expressed as primary drug investigated (C).
FIGURE3. Forest plot of the eects of cannabinoid treatment on Crohn’s Disease, assessed by reduction in CDAI in human studies.
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Couch etal
The largest effect size in DAI reduction was caused by
an enzyme inhibitor: the FAAH inhibitor URB597 (SMD
-4.43; 95% CI, -6.32 to -2.55). The largest effect size of DAI
reduction by an endocannabinoid was AEA (SMD -3.03; 95%
CI, -4.89 to -1.17); the largest effect size of DAI reduction
by a phytocannabinoid was CBD (SMD -0.56; 95% CI, -0.97
to -0.16; I2 = 29%), and the largest synthetic cannabinoid
effect size on DAI was AM1241 (SMD -3.11; 95% CI, -5.01
to -1.22). SMD and condence intervals of individual drugs
on DAI are given in Table4. Eighteen of 25 drugs had a large
effect size, 1 had a moderate effect size, and 6 had no signi-
cant effect onDAI.
Myeloperoxidase Activity(MPO)
Twenty-six publications investigated the effects of 21
cannabinoid drugs on MPO activity throughout 57 individ-
ual experiments (total n = 757, n = 419 in experimental vs
338 in control groups). Cannabinoid drugs reduced MPO in
comparison with the vehicle (SMD -1.26; 95% CI, -1.54 to
-0.97; I2=48.1%, Fig. 5, Table4). Overall, there was signi-
cant heterogeneity between studies, and there was signicant
subgroup difference (I2=48.1%; P<0.008). MPO was signif-
icantly reduced in mice and rats (SMD -1.28; 95% CI, -1.59 to
-0.98; I2=61%; and -1.06; 95% CI, -1.99 to -0.13; I2=56%,
The largest effect size in MPO reduction was caused by
the phytocannabinoid CBG (SMD -6.20; 95% CI, -9.90 to -2.50;
I2 not assessed). The largest effect size by an endocannabinoid
was PEA (SMD -2.74; 95% CI, -4.42 to -1.06; I2= 85%). The
largest synthetic cannabinoid effect size on MPO was caused
by ACEA (SMD -3.15; 95% CI, -4.75 to -1.55; I2 not assessed).
And the largest effect size of any enzyme or transport inhib-
itor was AA5HT (SMD -2.27; 95% CI, -4.05 to -0.49; I2 not
assessed). SMD and condence intervals of individual drugs on
MPO activity are given in Table4. Thirteen of 21 cannabinoid
drugs had a large clinical effect, the remaining of which had no
signicant effect on MPO.
Time of Administration
From the 50 publications examining the effect of cannab-
inoids on murine colitis, 28 studies administered cannabinoid
agents either simultaneously with colitis onset or prophy-
lactically. Seventeen studies administered drugs between 15
minutes and 7days after the onset of colitis. Additionally, 7
studies compared the benet of prophylactic cannabinoid use
to therapeutic, but did not nd any difference in efcacy. To
investigate if the timing of drug treatment affected DAI or
MPO, we compared study size-weighted effect sizes (depend-
ent variable) with time of administration (covariate) using
meta-regression. We found that the timing of drug admin-
istration weakly predicted effect size in reducing DAI and
MPO, although this was of borderline statistical signicance
(P= 0.09, R2=11%, and P =0.055, R2=41%, respectively,
Fig.6A and B).
FIGURE4. Forest plot of the eects of cannabinoid treatment on
Disease Activity Score subdivided by drug type. Time of administration
in relation to onset of colitis is given where “p” represents prophylactic
administration, and “t” represents therapeutic administration.
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Volume 24, Number 4, April 2018 The use of cannabinoids in colitis: a systematic review and meta-analysis
Quality and Risk ofBias
Of the 53 papers, 21 used randomization in their design,
7 reported blinding of assessment, 5 replicated their results in a
second species, and 14 replicated their ndings in a second model
of colitis. Fifty reported n ≥ 5 in control and experimental groups.
Fifteen publications reported specic numbers within groups.
All papers reported a clinically relevant endpoint. The median
study quality modied STAIR score was 5 out of 10 (mean
4.9, SD 2.29). Using meta-regression, higher quality scores pre-
dicted greater reductions in MPO activity (P=0.043, R2=65%,
Fig.6D), but not in DAI (P=0.98, R2=35%, Fig.6C).
The SYRCLE risk-of-bias score for each endpoint
showed a trend to larger reduction in DAI in studies with a
larger risk of bias (P=0.084, R2=69%, Fig.6E), but not MPO
(P=0.345, R2=8%, Fig.6F).
Funnel plots comparing MPO activity and DAI were
constructed and analysed statistically for bias. The presence of
publication bias was not found in either group (MPO: Egger’s
statistic P =0.570, Fig.7A; DAI: Egger’s statistic P = 0.274,
The aim of this study was to determine the efcacy of can-
nabinoid drugs in reducing gut inammation to aid the design
of further clinical studies. We found 53 studies that examined
this effect using endocannabinoids, phytocannabinoids, syn-
thetic cannabinoids, and enzyme and reuptake inhibitors across
multiple models of murine and human colitis. In both qual-
itative assessment and meta-analysis, these controlled studies
TABLE3: The Eects of Cannabinoids on Disease Activity Score Caused by Experimental Colitis Grouped by Drug
No. of Studies No. of animals SMD [95% CI] P I2 (%) Clinical signicance
PEA 6 118 -1.45 [-1.94, -0.96] <0.00001 25 High
AEA 1 12 -3.03 [-4.89, -1.17] 0.001 N/A High
CBD 12 181 -0.56 [-0.97, -0.16] 0.006 29 NS
THC 3 44 -0.53 [-1.24, 0.17] 0.14 0 NS
MMJ 1 30 -0.76 [-1.52, -0.00] 0.05 N/A Moderate
αβ Amyrin 4 28 -1.88 [-3.05, -0.72] 0.002 0 High
AM841 4 36 -1.87 [-3.57, -0.17] 0.03 66 High
βCaryophyllene 4 40 -1.52 [-2.32, -0.72] 0.0002 6 High
SAB378 4 56 0.28 [-0.38, 0.94] 0.41 28 NS
WIN55,212-2 4 60 -1.37 [-1.96, -0.78] <0.00001 0 High
CID16020046 2 16 -2.24 [-3.94, -0.54] 0.01 17 High
HU210 2 24 -2.89 [-6.24, 0.46] 0.09 81 NS
O-1602 2 28 -0.84 [-2.01, 0.33] 0.16 45 NS
ACEA 1 18 -0.87 [-1.85, 0.11] 0.08 N/A High
Adelmidrol 1 20 -1.85 [-2.94, -0.77] 0.0008 N/A High
AM1241 1 12 -3.11 [-5.01, -1.22] 0.001 N/A High
HU308 1 12 -0.73 [-1.92, 0.45] 0.23 N/A NS
Enzyme inhibitors
JWH133 4 53 -2.81 [-4.45, -1.17] 0.0008 71 High
PF3845 3 48 -2.21 [-3.11, -1.31] <0.00001 25 High
AA5HT 1 10 -2.16 [-3.90, -0.43] 0.01 N/A High
ARN2508 1 12 -2.66 [-4.38, -0.93] 0.002 N/A High
Compound 39 1 20 -1.47 [-2.48, -0.46] 0.004 N/A High
JZL184 1 22 -1.24 [-2.16, -0.31] 0.009 N/A High
URB597 1 18 -4.43 [-6.32, -2.55] <0.00001 N/A High
Transport inhibitors
VDM115 2 30 -3.06 [-4.21, -1.90] <0.00001 0 High
Total 68 948 -1.36 [-1.62, -1.09] <0.00001 61 High
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Couch etal
demonstrate that the use of cannabinoid drugs are benecial
in reducing colonic inammation in rats and mice, with unclear
effects in human subjects.
In animal studies, cannabinoids were shown to reduce
inammation both qualitatively and at meta-analysis. Across
experiments included in this review, CB2 agonists, FAAH inhib-
itors, and CBD were the most widely studied and showed the
greatest therapeutic benet across all endpoints. Subgroup
analyses suggested that CBG caused the greatest reduction in
MPO activity scores, followed by synthetic CB1 agonist ACEA.
However, both agents were only studied within a single publi-
cation. In the MPO analysis, the most studied drug was CBD,
with 157 animals across 7 publications, demonstrating a sig-
nicant effect on MPO activity reduction. Similarly, within
DAI analysis, CBD was again the most-studied single drug,
including 181 animals across 6 publications. Although CBD
demonstrated a signicant effect on DAI reduction, the largest
reduction in DAI was caused by the FAAH antagonist URB597,
studied in 1 publication. There was statistical heterogeneity in
both MPO and DAI analyses, which was partially accounted
for by subgroup differences. At meta-regression, factors leading
to subgroup differences were quality, timing, and risk ofbias.
Receptor targets were explored in 23 publications using
receptor-specic agonists or antagonists and receptor knock-
down. In murine colitis, agonism of the CB1 or CB2 receptor
brought about reduction in inammation, and at subgroup
analysis, the use of the synthetic CB1/CB2 agonists acting
demonstrated the greatest reduction in disease scores and MPO
activity. In addition, agonism of the PPARα, GPR55, and
GPR18 receptors also reduced inammation of the colon. The
wide variation in the measured inammatory endpoints across
these studies prevented further meta-analysis. Interestingly, the
use of the peripherally restricted synthetic agonist SAB378,
which agonises both CB1 and CB2 receptors, had no signicant
effect on either MPO activity or DAI. This is in contrast to ex
vivo explant human colonic data, which demonstrated that can-
nabinoid agonism with AEA or CBD was benecial in colonic
mucosal inammation, which were peripherally restricted by
TABLE4: The Eects of Cannabinoids on Mpo Activity Caused by Experimental Colitis Grouped by Drug
No. of Studies No. of animals SMD [95% CI] P I2 (%) Clinical signicance
PEA 7 94 -2.74 [-4.42, -1.06] 0.001 85 High
CBD 10 157 -1.03 [-1.40, -0.66] <0.00001 0 High
THC 3 29 -1.40 [-3.97, 1.17] 0.28 80 NS
CBC 1 10 -2.97 [-5.05, -0.89] 0.005 N/A High
CBG 1 10 -6.20 [-9.90, -2.50] 0.01 N/A High
βCaryophyllene 4 40 -1.26 [-2.48, -0.05] 0.04 60 High
AM841 4 48 -1.56 [-2.71, -0.41] 0.008 54 High
SAB378 4 42 -0.23 [-0.86, 0.39] 0.46 0 NS
WIN55,212-2 4 52 -1.74 [-2.81, -0.67] 0.001 57 High
αβ Amyrin 2 15 -0.38 [-1.48, 0.71] 0.5 0 NS
CID16020046 2 56 -1.04 [-1.61, -0.48] 0.0003 0 High
HU210 2 24 -0.63 [-1.48, 0.23] 0.15 2 NS
O-1602 2 20 -1.70 [-2.81, -0.60] 0.003 0 High
ACEA 1 16 -3.15 [-4.75, -1.55] 0.0001 N/A High
AM1241 1 10 -0.96 [-2.31, 0.39] 0.16 N/A NS
JWH133 1 16 -0.98 [-2.04, 0.07] 0.09 N/A NS
Ademidrol 1 20 -1.33 [-2.31, -0.34] 0.009 N/A High
Enzyme inhibitors
PF3745 3 46 -0.12 [-1.56, 1.32] 0.81 81 NS
AA5HT 1 10 -2.27 [-4.05, -0.49] 0.01 N/A High
URB597 1 16 -1.00 [-2.06, 0.06] 0.06 N/A NS
Transport inhibitors
VDM115 2 26 -1.91 [-3.72, -0.10] 0.04 59 High
Total 57 757 -1.26 [-1.54, -0.97] <0.00001 48.1 High
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Volume 24, Number 4, April 2018 The use of cannabinoids in colitis: a systematic review and meta-analysis
denition of the explant model.30, 31 Izzo et al9 found through
receptor antagonism that the effect of CBN in preventing
hypermobility caused by croton oil was mediated by CB1, but
not CB2. PEA was investigated by Capasso etal20, 32 using two
models of inammation-induced hypermotility. Using receptor
antagonists in both experiments, Capasso etal found that PEA,
in an OM model, acted through CB1, but not CB2 or PPARα.
In a CO model, PEA was still effective, but did not act through
CB1 or CB2. This suggests that the mechanism by which PEA
acts as an anti-inammatory agent was not mediated by a sin-
gle receptor, but by receptor codependence. ACEA was investi-
gated for receptor mechanism in 2 publications, both of which
found ACEA dependent on CB1. None of the reviewed studies
investigated a mechanism of action for AEA in gut inamma-
tion, however 1 ex vivo human study from Harvey etal found
that AEA prevented increased cytokine production in experi-
mentally inamed human mucosa and was dependent on CB2,
although the authors did not report antagonism of any other
The specic mechanism by which manipulation of the
cannabinoid system affects inammation is not clear. Esposito
et al33 demonstrated that PEA brought about anti-inamma-
tory effects on enteric glial cells acting at toll-like receptor 4,
suggesting that rather than acting at an epithelial mucosal level,
it acts at either an innate immune colonies or the enteric nerv-
ous system. This hypothesis has recently been evidenced by a
study demonstrating that both CBD and PEA do not act on
the immune response of epithelial cells, but are likely to require
the presence of other cell types, acting through down regulation
of NF-κβ.34 This is challenged by Cluny etal, who demonstrate
that peripherally restricted cannabinoids have a diminished
effect on inammation. Nevertheless, it is clear that the mech-
anism of action of cannabinoids does not simply lie at the epi-
thelial level, but is likely to reside within the gut-brainaxis.
From the clinical literature, we found 2 randomized
placebo-controlled studies examining the effect of phytocan-
nabinoids in humans. Our analysis found no overall effect
of THC or CBD on disease scores; however; there was large
statistical and clinical heterogeneity between these studies.
We found from meta-analysis that inhaled THC did have a
benecial effect on CDAI at 8 weeks, whereas CBD did not.
There may be several reasons for this heterogeneity: Firstly
in all groups, small cohort sizes were used which may have
overestimated positive or negative effects in both studies,
making meaningful conclusions difcult regarding the use of
CBD or THC in inammatory bowel disease. Secondly, within
the Naftali et al (2017) study, very low doses of CBD were
utilized compared to the use of CBD in other clinical trials,
which commonly used 600mg twice daily.35 Arecent trial in
drug-resistant epilepsy used daily for 4 weeks, with
a small number of participants experiencing side effects such
as vomiting and diarrhea.36 It is likely that in adult males such
FIGURE5. Forest plot of the eects of cannabinoid treatment on MPO
activity subdivided by drug type. Time of administration in relation to
onset of colitis is given, where “p” represents prophylactic administra-
tion and “t” represents therapeutic administration.
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Couch etal
FIGURE6. The eect of cannabinoid treatment on experimentally induced colitis determined by DAI (A) and MPO (B) predicted by timing of drug
administration in relation to colitis onset. The eect of study quality, determined by mSTAIR score, and SYRCLE score, on eect size in DAI (C, E) and
MPO (D, F). Study weights are represented by the diameter of the circle, with larger circles representing studies with largest weight in the analysis.
FIGURE7. Funnel plots evaluating for publication bias in (A) MPO activity and (B) DAI. Standard error of the standardized mean dierence (SE [SMD],
y axes) for each study is plotted against its eect size (SMD, x axes).
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Inflamm Bowel Dis
Volume 24, Number 4, April 2018 The use of cannabinoids in colitis: a systematic review and meta-analysis
10mg doses had no clinical effect on Crohn’s disease, as insuf-
cient plasma concentrations may have been reached due to
the poor bioavailability of oral CBD. Amajor aw within the
Naftali etal 2013 trial is that sham cigarettes contained can-
nabis sativa owers in which active cannabinoids had been
removed. However, it is unlikely that other compounds pres-
ent in cannabis (such as terpenes), which are known to have an
anti-inammatory effect, had also been removed, which may
have introduced positive bias into the study.37 However, des-
pite these drawbacks, the Naftali etal 2013 trial demonstrated
a signicant reduction in pain and the use of steroid therapy,
with increased sleep and satisfaction levels with THC use com-
pared with placebo. Although not included in this analysis,
a study from Storr etal38 demonstrated that although can-
nabis use provided symptomatic relief from Crohn’s disease,
the risk of salvage surgery was increased within 6months of
use (OR: 5.03; 95% CI, 1.45–17.46). However, these ndings
have not yet been supported from randomized, blinding con-
trolled trials. We may suggest, therefore, that phytocannabi-
noid use may be a future therapy in intestinal inammation.
Although before rm conclusions are drawn, further clinical
studies examining their effects should be conducted at higher,
therapeutic dosages with adequately powered cohort sizes. As
MMJ use in inammatory bowel disease has been justied
because of its effects on appetite and diarrhea, studies may be
designed to examine these quality-of-life–affecting endpoints
We found that most of the existing cannabinoid-gut
research focuses on the therapeutic potential of CBD. This is
unsurprising as CBD is currently used clinically, is well toler-
ated, and has shown consistently positive results. Nine studies
found a positive, dose-dependent effect on local inammatory
cytokine expression, COX2 activation, MPO activity, enteric
glial cell activation, and caspase-3 production, with associated
improvements in macroscopic and histologic grades of inam-
mation.39–46 One study also showed that intraperitoneal CBD
administration decreased oxidative-stress scores of peripheral
lung and brain tissue following intestinal inammation,47 add-
ing to the existing evidence that CBD maintains the gut barrier
during inammation.48 Despite being the most-studied drug,
the mechanism by which CBD acts was not made clear by this
review. One study by De Fillipis etal44 found that hypermo-
tility caused by LPS administration in mice was reduced by
CBD through a CB1 dependent mechanism. Similarly, Capasso
et al (2008) found that CBD prevented croton oil-induced
hypermotility via CB1. de Fillipis et al (2011) demonstrated
that in human explant tissue S100B levels, as a marker of glial
cell activation, in vitro was decreased by CBD in a PPARγ
dependent mechanism (although other antagonists were not
The timing of cannabinoid administration correlated
with reduction in effect on colitis activity, although this did
not reach statistical signicance. There was a correlation
between the time of drug administration and effect size in
both DAI and MPO reduction, with earlier administration
of cannabinoid drugs producing a greater effect size. This
suggests that in clinical trials, cannabinoids may be used
prophylactically and therapeutically. There is promise, there-
fore, that compounds targeting the endocannabinoid system
may be able to not only prevent colonic inammation, but
also treat established intestinal inammatory conditions.
Because it is not clear if cannabinoids are more effective
when treating new-onset or established intestinal inamma-
tion, further study designs should investigate this endpoint
One important potential area for research is the combin-
ation of cannabinoid drugs with existing treatments for inam-
matory bowel disease. In clinical practice, it is common to treat
patients with acute severe Crohn’s disease and ulcerative colitis
with a combination of agents, such as antibiotic, anti-TNFα,
and corticosteroid therapy. One study compared the efcacy of
CBD and THC with that of sulphasalazine, a 5-ASA, a drug
commonly used in clinical practice.45 Although in this study
CBD and THC efcacy were comparable to that of sulphasala-
zine, the authors did not examine for the potential additive or
subtractive effect of these agents in the context of colitis.
The ndings of this study are limited by several factors
typically seen in meta-analyses and systematic reviews. We
found signicant heterogeneity between subgroups in both
DAI and MPO analyses, which suggested that 11% and 41%
of this was due to the difference in time of administration in
terms of changes in DAI and MPO, respectively. Additionally,
we found risk-of-bias study design to be high and median study
quality to be relatively low. Meta-regression demonstrated that
these factors signicantly correlated with study outcomes.
Although we did not analyze for differences between scoring
systems and mode of colitis, these factors may have also con-
tributed to heterogeneity and inuenced outcome. We sought
to overcome this variability between scoring systems with ran-
dom effects analysis. Additionally, within this review we have
examined the effect of cannabinoid drugs en mass, which may
have affected the overall outcome of meta-analyses. It is pos-
sible that some articles may not have been identied in initial
searches, or conference abstracts may have been missed from
the search period. Lastly, where control groups were compared
to multiple experimental groups within the same set of exper-
iments, variance and SMD may be exaggerated, leading to
In conclusion, we have shown in this systematic review
and meta-analysis that cannabinoid drugs are benecial in
treating experimentally-induced murine models of colitis.
These positive ndings support the development of further
human clinical trials. Current literature converges on CBD,
and to avoid research bias, the effect of all cannabinoid drugs,
including the large number of phytocannabinoid drugs not yet
investigated, should also be investigated.
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Volume 24, Number 4, April 2018
Couch etal
1. Kappelman MD, Rifas-Shiman SL, Kleinman K, etal. The prevalence and geo-
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Volume 24, Number 4, April 2018
Couch etal
Section/topic # Checklist item
Reported on
page #
Title 1 Identify the report as a systematic review, meta-analysis, or both. 1
Structured summary 2 Provide a structured summary including, as applicable: background; objectives; data sources;
study eligibility criteria, participants, and interventions; study appraisal and synthesis meth-
ods; results; limitations; conclusions and implications of key ndings; systematic review
registration number.
Rationale 3 Describe the rationale for the review in the context of what is already known. 4
Objectives 4 Provide an explicit statement of questions being addressed with reference to participants, inter-
ventions, comparisons, outcomes, and study design (PICOS).
Protocol and registration 5 Indicate if a review protocol exists, if and where it can be accessed (e.g., Web address), and, if
available, provide registration information including registration number.
Eligibility criteria 6 Specify study characteristics (e.g., PICOS, length of follow-up) and report characteristics (e.g.,
years considered, language, publication status) used as criteria for eligibility, giving rationale.
Information sources 7 Describe all information sources (e.g., databases with dates of coverage, contact with study
authors to identify additional studies) in the search and date last searched.
Search 8 Present full electronic search strategy for at least one database, including any limits used, such
that it could be repeated.
Study selection 9 State the process for selecting studies (i.e., screening, eligibility, included in systematic review,
and, if applicable, included in the meta-analysis).
Data collection process 10 Describe method of data extraction from reports (e.g., piloted forms, independently, in dupli-
cate) and any processes for obtaining and conrming data from investigators.
Data items 11 List and dene all variables for which data were sought (e.g., PICOS, funding sources) and any
assumptions and simplications made.
Risk of bias in individual
12 Describe methods used for assessing risk of bias of individual studies (including specication
of whether this was done at the study or outcome level), and how this information is to be
used in any data synthesis.
Summary measures 13 State the principal summary measures (e.g., risk ratio, difference in means). 7
Synthesis of results 14 Describe the methods of handling data and combining results of studies, if done, including
measures of consistency (e.g., I2) for each meta-analysis.
Risk of bias across studies 15 Specify any assessment of risk of bias that may affect the cumulative evidence (e.g., publication
bias, selective reporting within studies).
Additional analyses 16 Describe methods of additional analyses (e.g., sensitivity or subgroup analyses, meta-regres-
sion), if done, indicating which were pre-specied.
Study selection 17 Give numbers of studies screened, assessed for eligibility, and included in the review, with rea-
sons for exclusions at each stage, ideally with a ow diagram.
Study characteristics 18 For each study, present characteristics for which data were extracted (e.g., study size, PICOS,
follow-up period) and provide the citations.
Risk of bias within studies 19 Present data on risk of bias of each study and, if available, any outcome level assessment (see
item 12).
Results of individual
20 For all outcomes considered (benets or harms), present, for each study: (a) simple summary
data for each intervention group (b) effect estimates and condence intervals, ideally with a
forest plot.
Synthesis of results 21 Present results of each meta-analysis done, including condence intervals and measures of
Risk of bias across studies 22 Present results of any assessment of risk of bias across studies (see Item 15). 12
Additional analysis 23 Give results of additional analyses, if done (e.g., sensitivity or subgroup analyses, meta-regres-
sion [see Item16]).
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Volume 24, Number 4, April 2018 The use of cannabinoids in colitis: a systematic review and meta-analysis
Section/topic # Checklist item
Reported on
page #
Summary of evidence 24 Summarize the main ndings including the strength of evidence for each main outcome; con-
sider their relevance to key groups (e.g., healthcare providers, users, and policy makers).
Limitations 25 Discuss limitations at study and outcome level (e.g., risk of bias), and at review-level (e.g., in-
complete retrieval of identied research, reporting bias).
Conclusions 26 Provide a general interpretation of the results in the context of other evidence, and implications
for future research.
Funding 27 Describe sources of funding for the systematic review and other support (e.g., supply of data);
role of funders for the systematic review.
From: Moher D, Liberati A, Tetzlaff J, Altman DG, The PRISMA Group (2009). Preferred Reporting Items for Systematic Reviews and Meta-Analyses: The PRISMA Statement.
PLoS Med 67: e1000097. doi:10.1371/journal.pmed1000097.
APPENDIX: Continued
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... The effectiveness of cannabinoids in inflammatory diseases has been demonstrated on various animal models. Couch et al. published a comprehensive meta-analysis presenting undeniable evidence that cannabinoids prove to be effective in intestinal inflammatory conditions [69]. The disease activity index (DAI) score and levels of myeloperoxidase (MPO) activity were the criteria of choice for the measurement of the effects of various synthetic and phyto-cannabinoids. ...
... While THC showed some clinical benefits, CBD failed to improve the DAI in active Crohn's disease. However, both trials received some criticism for methodological flaws, small patient groups and various other biases [69,90]. ...
Full-text available
Recent studies have identified great similarities and interferences between the epithelial layers of the digestive tract, the airways and the cutaneous layer. The relationship between these structures seems to implicate signaling pathways, cellular components and metabolic features, and has led to the definition of a gut-lung-skin barrier. Inflammation seems to involve common features in these tissues; therefore, analyzing the similarities and differences in the modulation of its bi-omarkers can yield significant data promoting a better understanding of the particularities of specific signaling pathways and cellular effects. Cannabinoids are well known for a wide array of beneficial effects, including anti-inflammatory properties. This paper aims to explore the effects of natural and synthetic cannabinoids, including the components of the endocannabinoid system, in relation to the inflammation of the gut-lung-skin barrier epithelia. Recent advancements in the use of cannabinoids as anti-inflammatory substances in various disorders of the gut, lungs and skin are detailed. Some studies have reported mixed or controversial results, and these have also been addressed in our paper.
... 35 Several in vitro studies suggest a dose-dependent effect of THC and other cannabinoids on cellular apoptosis and local inflammatory processes, such as COX-2 activation, cytokine expression, and caspase-3 production. 16,23 Given the widespread use of cannabis in the general population, it is critical that clinicians understand the potential implications of cannabis in the surgical patient. ...
Full-text available
Cannabis use is increasingly prevalent. Cannabinoid receptors regulate pro-inflammatory cytokines, and compounds in marijuana exert diverse physiologic effects. As more patients use cannabis, clinicians should recognize implications of perioperative cannabis use. Although the role of cannabis use in perioperative pain control has been explored, little is known about its effect on perioperative wound healing or on hematologic, pulmonary, and cardiovascular physiology. Methods: We searched PubMed for English-language articles related to cannabis (ie, marijuana, cannabidiol oil, and tetrahydrocannabinol) and wound healing, cardiovascular, pulmonary, or hematologic outcomes, and surgery. Titles and abstracts were reviewed, and relevant articles were analyzed. Human, animal, and pathology studies were included. Editorials, case reports, and review articles were excluded. Results: In total, 2549 wound healing articles were identified; 5 human studies and 8 animal/pathology studies were included. Results were conflicting. An estimated 2900 articles related to cardiovascular effects were identified, of which 2 human studies were included, which showed tetrahydrocannabinol and marijuana caused tachycardia. A total of 142 studies regarding pulmonary effects were identified. Three human studies were included, which found no difference in respiratory complications. In total, 114 studies regarding hematologic effects were identified. The 3 included human studies found conflicting venous thromboembolism risks. The overall study quality was poor. Information about dose/duration, administration route, and follow-up was reported with variable completeness. Conclusions: Surgeons should consider effects of cannabis in the perioperative setting. Little is known about its perioperative effects on wound healing, or on cardiovascular, pulmonary, and hematologic physiology. Further research should elucidate the effects of administration route, dose, and timing of cannabis use among surgical patients.
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An alternative in vitro propagation protocol for medical Cannabis sativa L. cultivars for pharmaceutical industrial use was established. The aim of the protocol was to reduce the culture time, offering healthy and aseptic propagating material, while making the whole process more economic for industrial use. The propagation procedure was performed using plastic autoclavable vented and non-vented vessels, containing porous rooting fine-milled sphagnum peat moss-based sponges, impregnated in ½ Murashige and Skoog liquid growth medium, supplemented with indole-3-butyric acid (IBA) at various concentrations (0, 2.46, 4.92, and 9.84 µM) or by dipping nodal cuttings into 15 mM IBA aqueous solution. The highest average root numbers per cutting, 9.47 and 7.79 for high cannabidiol (H_CBD) and high cannabigerol (H_CBG) varieties, respectively, were achieved by dipping the cuttings into IBA aqueous solution for 4 min and then placing them in non-vented vessels. The maximum average root length in H_CBD (1.54 cm) and H_CBG (0.88 cm) was ascertained using 2.46 μM filter sterilized IBA in non-vented vessels. Filter-sterilized IBA at concentrations of 2.46 μM in vented and 4.92 μM in non-vented vessels displayed the maximum average rooting percentages in H_CBD (100%) and H_CBG (95.83%), respectively. In both varieties, maximum growth was obtained in non-vented vessels, when the medium was supplemented with 4.92 μM filter-sterilized IBA. Significant interactions between variety and vessel type and variety and IBA treatments were observed in relation to rooting traits. Approximately 95% of plantlets were successfully established and acclimatized in field. This culture system can be used not only for propagating plant material at an industrial scale but also to enhance the preservation and conservation of Cannabis genetic material.
Increased interest in cannabis as a potential treatment and/or adjuvant therapy for inflammatory bowel disease (IBD) has been driven by patients with refractory disease seeking relief as well those who desire alternatives to conventional therapies. Available data have shown a potential role of cannabis as a supportive medication, particularly in pain reduction; however, it remains unknown whether cannabis has any impact on the underlying inflammatory process of IBD. The purpose of this review article is to summarize the available literature concerning the use of cannabis for the treatment of IBD and highlight potential areas for future study.
In recent years, interest in using cannabinoids in horses has grown substantially. There is a paucity of standardized research using cannabis in equines; however, early studies and anecdotal experience has suggested that CBD and full spectrum hemp products can be very useful as anxiolytics and for analgesia in horses. Initial studies have shown safety in horses receiving CBD products; veterinarians and veterinary professionals are urged to seek out proof of product analysis, preferably from independent laboratories. Pharmacokinetic data is provided in this chapter from four studies to help guide clinicians seeking out cannabinoids as an alternative or adjunct therapy in equine medicine. Specific dosing protocols used by the authors are provided for several indications: anxiety, osteoarthritis, laminitis, and from a published case report of mechanical allodynia in a horse.
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Peripheral inflammatory conditions, including those localized to the gastrointestinal tract, are highly comorbid with psychiatric disorders such as anxiety and depression. These behavioral symptoms are poorly managed by conventional treatments for inflammatory diseases and contribute to quality of life impairments. Peripheral inflammation is associated with sustained elevations in circulating glucocorticoid hormones, which can modulate central processes, including those involved in the regulation of emotional behavior. The endocannabinoid (eCB) system is exquisitely sensitive to these hormonal changes and is a significant regulator of emotional behavior. The impact of peripheral inflammation on central eCB function, and whether this is related to the development of these behavioral comorbidities remains to be determined. To examine this, we employed the trinitrobenzene sulfonic acid-induced model of colonic inflammation (colitis) in adult, male, Sprague Dawley rats to produce sustained peripheral inflammation. Colitis produced increases in behavioral measures of anxiety and elevations in circulating corticosterone. These alterations were accompanied by elevated hydrolytic activity of the enzyme fatty acid amide hydrolase (FAAH), which hydrolyzes the eCB anandamide (AEA), throughout multiple corticolimbic brain regions. This elevation of FAAH activity was associated with broad reductions in the content of AEA, whose decline was driven by central corticotropin releasing factor type 1 receptor signaling. Colitis-induced anxiety was reversed following acute central inhibition of FAAH, suggesting that the reductions in AEA produced by colitis contributed to the generation of anxiety. These data provide a novel perspective for the pharmacological management of psychiatric comorbidities of chronic inflammatory conditions through modulation of eCB signaling.
Plant-based therapies date back centuries. Cannabis sativa is one such plant that was used medicinally up until the early part of the 20th century. Although rich in diverse and interesting phytochemicals, cannabis was largely ignored by the modern scientific community due to its designation as a schedule 1 narcotic and restrictions on access for research purposes. There was renewed interest in the early 1990s when the endocannabinoid system (ECS) was discovered, a complex network of signaling pathways responsible for physiological homeostasis. Two key components of the ECS, cannabinoid receptor 1 (CB1) and cannabinoid receptor 2 (CB2), were identified as the molecular targets of the phytocannabinoid Δ9-tetrahydrocannabinol (Δ9-THC). Restrictions on access to cannabis have eased worldwide, leading to a resurgence in interest in the therapeutic potential of cannabis. Much of the focus has been on the two major constituents, Δ9-THC and cannabidiol (CBD). Cannabis contains over 140 phytocannabinoids, although only a handful have been tested for pharmacological activity. Many of these minor cannabinoids potently modulate receptors, ionotropic channels, and enzymes associated with the ECS and show therapeutic potential individually or synergistically with other phytocannabinoids. The following review will focus on the pharmacological developments of the next generation of phytocannabinoid therapeutics.
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High cannabidiol (CBD) and cannabigerol (CBG) varieties of Cannabis sativa L., a species with medicinal properties, were regenerated in vitro. Explants of nodal segments including healthy axillary bud, after sterilization, were placed in Murashige-Skoog (MS) culture medium. The shoots formed after 30 days were subcultured in full- or half-strength MS medium supplemented with several concentrations of 6-benzyl-amino-purine (BA) or thidiazuron (TDZ). The highest average number and length of shoots was achieved when both full and half-strength MS media were supplemented with 4.0 μM BA. The presence of 4.0 μM TDZ showed also comparable results. BA and TDZ at concentrations of 4.0, 8.0 μM and 2.0, 4.0 μM respectively, displayed the maximum shooting frequency. The new shoots were transferred on the same media and were either self-rooted or after being enhanced with different concentrations of indole-3-butyric acid (IBA) or α-naphthalene acetic acid (NAA). Presence of 2.0 or 4.0 μM IBA or 4.0 μM NAA resulted to the optimum rooting rates. The maximum average number and length of roots per shoot was observed when the culture media was supplemented with 4.0 μM IBA or NAA. Approximately 92% of the plantlets were successfully established and acclimatized in field. The consistency of the chemical profile of the acclimatized in vitro propagated clones was assessed using quantitative 1H-NMR high throughput screening. In each variety, analysis of the micropropagated plant in comparison with the mother plant showed no statistically significant differences (p ≤ 0.05) in CBD+ cannabidiolic acid (CBDA) and CBG+ cannabigerolic acid (CBGA) content respectively, thus indicating stability of their chemical profile.
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Purpose of review To review recent clinical evidence surrounding the use of cannabinoids and cannabis in gastrointestinal diseases, particularly inflammatory bowel disease (IBD) and functional gut disorders. A second aim is to evaluate the current status of gastrointestinal related adverse effects which have been linked to cannabis use, specifically cannabis hyperemesis syndrome (CHS) and acute pancreatitis. Recent findings Observational and prospective studies suggest that cannabinoids improve IBD symptoms. Small prospective clinical trials have not shown any effects on objective inflammatory findings, other than one recent paper in ulcerative colitis, in abstract form only, which suggests endoscopic improvement. Short duration mechanistic studies in functional gut disorders suggest cannabinoids may attenuate gastric emptying and slow colonic motility but appear to have less effect on sensory thresholds in the gut. Summary In general, while mostly uncontrolled data suggests cannabis may improve symptoms in IBD (and to a lesser degree functional gut disorders), this is not likely due to any substantial anti-inflammatory effect. Much remains unknown about CHS etiology and complete abstinence from cannabinoids remains the generally accepted treatment strategy. Population-based studies do not suggest that cannabis use is related to acute pancreatitis. Further research is certainly warranted.
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Inflammatory bowel disorders can be associated with alterations in gut microbiota (dysbiosis) and behavioral disturbances. In experimental colitis, administration of fish oil (FO) or cannabinoids, such as cannabidiol (CBD), reduce inflammation. We investigated the effect of combined FO/CBD administration on inflammation and dysbiosis in the dextran sulphate sodium (DSS) model of mouse colitis, which also causes behavioral disturbances. Colitis was induced in CD1 mice by 4% w/v DSS in drinking water for five consecutive days followed by normal drinking water. FO (20–75 mg/mouse) was administered once a day starting two days after DSS, whereas CBD (0.3–30 mg/kg), alone or after FO administration, was administered once a day starting 3 days after DSS, until day 8 (d8) or day 14 (d14). Inflammation was assessed at d8 and d14 (resolution phase; RP) by measuring the Disease Activity Index (DAI) score, change in body weight, colon weight/length ratio, myeloperoxidase activity and colonic interleukin (IL)-1β (IL-1β), IL-10, and IL-6 concentrations. Intestinal permeability was measured with the fluorescein isothiocyanate-dextran. Behavioral tests (novel object recognition (NOR) and light/dark box test) were performed at d8. Fecal microbiota composition was determined by ribosomal 16S DNA sequencing of faecal pellets at d8 and d14. DSS-induced inflammation was stronger at d8 and accompanied by anxiety-like behavior and impaired recognition memory. FO (35, 50, 75 mg/mouse) alone reduced inflammation at d8, whereas CBD alone produced no effect at any of the doses tested; however, when CBD (3, 10 mg/kg) was co-administered with FO (75 mg/mouse) inflammation was attenuated. FO (20 mg/mouse) and CBD (1 mg/kg) were ineffective when given alone, but when co-administered reduced all inflammatory markers and the increased intestinal permeability at both d8 and d14, but not the behavioral impairments. FO, CBD, and their combination affected gut bacteria taxa that were not affected by DSS per se. Akkermansia muciniphila, a species suggested to afford anti-inflammatory action in colitis, was increased by DSS only at d14, but its levels were significantly elevated by all treatments at d8. FO and CBD co-administered at per se ineffective doses reduce colon inflammation, in a manner potentially strengthened by their independent elevation of Akkermansia muciniphila. © Copyright © 2020 Silvestri, Pagano, Lacroix, Venneri, Cristiano, Calignano, Parisi, Izzo, Di Marzo and Borrelli.
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Background Cannabidiol (CBD) is an anti-inflammatory cannabinoid shown to be beneficial in a mouse model of IBD. Lacking any central effect, cannabidiol is an attractive option for treating inflammatory diseases. AimTo assess the effects of cannabidiol on Crohn’s disease in a randomized placebo-controlled trial. Patients and Methods Twenty patients aged 18–75 years with a Crohn’s disease activity index (CDAI) >200 were randomized to receive oral (10 mg) CBD or placebo twice daily. Patients did not respond to standard treatment with steroids (11 patients), thiopurines (14), or TNF antagonists (11). Disease activity and laboratory parameters were assessed during 8 weeks of treatment and 2 weeks thereafter. Other medical treatment remained unchanged. ResultsOf 20 patients recruited 19 completed the study. Their mean age was 39 ± 15, and 11 were males. The average CDAI before cannabidiol consumption was 337 ± 108 and 308 ± 96 (p = NS) in the CBD and placebo groups, respectively. After 8 weeks of treatment, the index was 220 ± 122 and 216 ± 121 in the CBD and placebo groups, respectively (p = NS). Hemoglobin, albumin, and kidney and liver function tests remained unchanged. No side effects were observed. Conclusion In this study of moderately active Crohn’s disease, CBD was safe but had no beneficial effects. This could be due to lack of effect of CBD on Crohn’s disease, but could also be due to the small dose of CBD, the small number of patients in the study, or the lack of the necessary synergism with other cannabinoids. Further investigation is warranted. ClinicalTrials.govNCT01037322.
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Background Ulcerative colitis (UC) is strongly associated with inflammation and intestinal barrier disorder. The nonselective cannabinoid receptor agonist HU210 has been shown to ameliorate inflamed colon in colitis, but its effects on intestinal barrier function and extraintestinal inflammation are unclear. AimsTo investigate the effects and the underlying mechanism of HU210 action on the UC in relation to a role of TLR4 and MAP kinase signaling. Methods Wild-type (WT) and TLR4 knockout (Tlr4−/−) mice were exposed to 4% dextran sulfate sodium (DSS) for 7 days. The effects of HU210 on inflammation and intestinal barrier were explored. ResultsUpon DSS challenge, mice suffered from bloody stool, colon shortening, intestinal mucosa edema, pro-inflammatory cytokine increase and intestinal barrier destruction with goblet cell depletion, increased intestinal microflora accompanied with elevated plasma lipopolysaccharide, reduced mRNA expression of the intestinal tight junction proteins, and abnormal ratio of CD4+/CD8+ T cells in the intestinal Peyer’s patches. Pro-inflammatory cytokines in the plasma and the lung, as well as pulmonary myeloperoxidase activity, indicators of extraintestinal inflammation were increased. Protein expression of p38α and pp38 was up-regulated in the colon of WT mice. Tlr4−/− mice showed milder colitis. HU210 reversed the intestinal barrier changes in both strains of mice, but alleviated inflammation only in WT mice. Conclusions Our study indicates that in experimental colitis, HU210 displays a protective effect on the intestinal barrier function independently of the TLR4 signaling pathway; however, in the extraintestinal tissues, the anti-inflammatory action seems through affecting TLR4-mediated p38 mitogen-activated protein kinase pathway.
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AIM To investigate the anti-inflammatory effect and the possible mechanisms of an agonist of cannabinoid (CB) receptors, WIN55-212-2 (WIN55), in mice with experimental colitis, so as to supply experimental evidence for its clinical use in future. METHODS We established the colitis model in C57BL/6 mice by replacing the animals’ water supply with 4% dextran sulfate sodium (DSS) for 7 consecutive days. A colitis scoring system was used to evaluate the severity of colon local lesion. The plasma levels of proinflammatory cytokines, such as tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6), and the myeloperoxidase (MPO) activity in colon tissue were measured. The expressions of cannabinoid receptors, claudin-1 protein, p38 mitogen-activated protein kinase (p38MAPK) and its phosphorylated form (p-p38) in colon tissue were determined by immunohistochemistry and Western blot. In addition, the effect of SB203580 (SB), an inhibitor of p38, was investigated in parallel experiments, and the data were compared with those from intervention groups of WIN55 and SB alone or used together. RESULTS The results demonstrated that WIN55 or SB treatment alone or together improved the pathological changes in mice with DSS colitis, decreased the plasma levels of TNF-α, and IL-6, and MPO activity in colon. The enhanced expression of claudin-1 and the inhibited expression of p-p38 in colon tissues were found in the WIN55-treated group. Besides, the expression of CB1 and CB2 receptors was enhanced in the colon after the induction of DSS colitis, but reduced when p38MAPK was inhibited. CONCLUSION These results confirmed the anti-inflammatory effect and protective role of WIN55 on the mice with experimental colitis, and revealed that this agent exercises its action at least partially by inhibiting p38MAPK. Furthermore, the results showed that SB203580, affected the expression of CB1 and CB2 receptors in the mouse colon, suggesting a close linkage and cross-talk between the p38MAPK signaling pathway and the endogenous CB system.
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Anecdotal and scientific evidence suggests that Cannabis use may be beneficial in inflammatory bowel disease (IBD) patients. Here, we have investigated the effect of a standardized Cannabis sativa extract with high content of cannabidiol (CBD), here named CBD BDS for “CBD botanical drug substance,” on mucosal inflammation and hypermotility in mouse models of intestinal inflammation. Colitis was induced in mice by intracolonic administration of dinitrobenzenesulfonic acid (DNBS). Motility was evaluated in the experimental model of intestinal hypermotility induced by irritant croton oil. CBD BDS or pure CBD were given - either intraperitoneally or by oral gavage – after the inflammatory insult (curative protocol). The amounts of CBD in the colon, brain, and liver after the oral treatments were measured by high-performance liquid chromatography coupled to ion trap-time of flight mass spectrometry. CBD BDS, both when given intraperitoneally and by oral gavage, decreased the extent of the damage (as revealed by the decrease in the colon weight/length ratio and myeloperoxidase activity) in the DNBS model of colitis. It also reduced intestinal hypermotility (at doses lower than those required to affect transit in healthy mice) in the croton oil model of intestinal hypermotility. Under the same experimental conditions, pure CBD did not ameliorate colitis while it normalized croton oil-induced hypermotility when given intraperitoneally (in a dose-related fashion) or orally (only at one dose). In conclusion, CBD BDS, given after the inflammatory insult, attenuates injury and motility in intestinal models of inflammation. These findings sustain the rationale of combining CBD with other minor Cannabis constituents and support the clinical development of CBD BDS for IBD treatment.
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Cannabinoids modulate intestinal permeability through CB1 The endocannabinoid-like compounds oleoylethanolamine (OEA) and palmitoylethanolamine (PEA) play an important role in digestive regulation, and we hypothesized they would also modulate intestinal permeability. Transepithelial electrical resistance (TEER) was measured in human Caco-2 cells to assess permeability after application of OEA and PEA and relevant antagonists. Cells treated with OEA and PEA were stained for cytoskeletal F-actin changes and lysed for immunoassay. OEA and PEA were measured by liquid chromatography-tandem mass spectrometry. OEA (applied apically, logEC50 -5.4) and PEA (basolaterally, logEC50 -4.9; apically logEC50 -5.3) increased Caco-2 resistance by 20-30% via transient receptor potential vanilloid (TRPV)-1 and peroxisome proliferator-activated receptor (PPAR)-α. Preventing their degradation (by inhibiting fatty acid amide hydrolase) enhanced the effects of OEA and PEA. OEA and PEA induced cytoskeletal changes and activated focal adhesion kinase and ERKs 1/2, and decreased Src kinases and aquaporins 3 and 4. In Caco-2 cells treated with IFNγ and TNFα, OEA (via TRPV1) and PEA (via PPARα) prevented or reversed the cytokine-induced increased permeability compared to vehicle (0.1% ethanol). PEA (basolateral) also reversed increased permeability when added 48 or 72 h after cytokines (P < 0.001, via PPARα). Cellular and secreted levels of OEA and PEA (P < 0.001-0.001) were increased in response to inflammatory mediators. OEA and PEA have endogenous roles and potential therapeutic applications in conditions of intestinal hyperpermeability and inflammation.-Karwad, M. A., Macpherson, T., Wang, B., Theophilidou, E., Sarmad, S., Barrett, D. A., Larvin, M., Wright, K. L., Lund, J. N., O'Sullivan, S. E. Oleoylethanolamine and palmitoylethanolamine modulate intestinal permeability in vitro via TRPV1 and PPARα.
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Activation of cannabinoid receptor 2 (CB2R) ameliorates inflammation, but the underlying mechanism remains unclear. In the present study, we examined whether activation of CB2R could suppress the nucleotide-binding domain and leucine-rich repeat protein 3 (NLRP3) inflammasome. In peritoneal macrophages isolated from C57BL/6 mice, LPS/DSS challenge for 24 h increased the expression of the components of NLRP3 inflammasome NLRP3, Casp-1 p20/Casp-1 p45 ratio, proIL-1β and IL-1β and also enhanced autophagy (LC3-II/LC3-I ratio, Beclin-1 and SQSTM1). Pretreatment of peritoneal macrophages with HU 308, a selective CB2R agonist, attenuated LPS/DSS-induced NLRP3 inflammasome activation, but further enhanced autophagy. In comparison with wild-type (WT) control, peritoneal macrophages from CB2R knockout (KO) mice had more robust NLRP3 inflammasome activation and attenuated autophagy upon LPS/DSS challenge. Knockdown autophagy-related gene 5 (Atg5) with a siRNA in peritoneal macrophages attenuated the inhibitory effects of HU 308 on LPS/DSS-induced NLRP3 inflammasome activation in vitro. In vivo, HU308 treatment attenuated DSS-induced colitis mice associated with reduced colon inflammation and inhibited NLRP3 inflammasome activation in wild-type mice. In CB2R KO mice, DSS-induced inflammation and NLRP3 inflammasome activation were more pronounced than those in WT control. Finally, we demonstrated that AMPK-mTOR-P70S6K signaling pathway was involved in this CB2R-mediated process. We conclude that activation of CB2R ameliorates DSS-induced colitis through enhancing autophagy that may inhibit NLRP3 inflammasome activation in macrophages.
Objective: We sought to quantify the anti-inflammatory effects of two cannabinoid drugs, cannabidiol (CBD) and palmitoylethanolamide (PEA), in cultured cell lines and compared this effect with experimentally inflamed explant human colonic tissue. These effects were explored in acutely and chronically inflamed colon, using inflammatory bowel disease and appendicitis explants. Design: Caco-2 cells and human colonic explants collected from elective bowel cancer, inflammatory bowel disease (IBD) or acute appendicitis resections, and were treated with the following drug treatments: vehicle, an inflammatory protocol of interferon γ (IFNγ) and tumour necrosis factor α (TNFα; 10 ng/ml), inflammation and PEA (10 µM), inflammation and CBD (10 µM), and PEA or CBD alone, CBD or vehicle were added simultaneously with IFNγ. Nine intracellular signalling phosphoproteins were determined by multiplex. Inflammatory cytokine secretion was determined using ELISA. Receptor mechanisms were investigated using antagonists for CB1, CB2, PPARα, PPARγ, TRPV1 and GPR55. Results: IFNγ and TNFα treatment increased phosphoprotein and cytokine levels in Caco-2 cultures and colonic explants. Phosphoprotein levels were significantly reduced by PEA or CBD in Caco-2 cultures and colonic explants. CBD and PEA prevented increases in cytokine production in explant colon, but not in Caco-2 cells. CBD effects were blocked by the CB2 antagonist AM630 and TRPV1 antagonist SB366791. PEA effects were blocked by the PPARα antagonist GW6471. PEA and CBD were anti-inflammatory in IBD and appendicitis explants. Conclusion: PEA and CBD are anti-inflammatory in the human colon. This effect is not seen in cultured epithelial cells. Appropriately sized clinical trials should assess their efficacy.
Background The Dravet syndrome is a complex childhood epilepsy disorder that is associated with drug-resistant seizures and a high mortality rate. We studied cannabidiol for the treatment of drug-resistant seizures in the Dravet syndrome. Methods In this double-blind, placebo-controlled trial, we randomly assigned 120 children and young adults with the Dravet syndrome and drug-resistant seizures to receive either cannabidiol oral solution at a dose of 20 mg per kilogram of body weight per day or placebo, in addition to standard antiepileptic treatment. The primary end point was the change in convulsive-seizure frequency over a 14-week treatment period, as compared with a 4-week baseline period. Results The median frequency of convulsive seizures per month decreased from 12.4 to 5.9 with cannabidiol, as compared with a decrease from 14.9 to 14.1 with placebo (adjusted median difference between the cannabidiol group and the placebo group in change in seizure frequency, −22.8 percentage points; 95% confidence interval [CI], −41.1 to −5.4; P=0.01). The percentage of patients who had at least a 50% reduction in convulsive-seizure frequency was 43% with cannabidiol and 27% with placebo (odds ratio, 2.00; 95% CI, 0.93 to 4.30; P=0.08). The patient’s overall condition improved by at least one category on the seven-category Caregiver Global Impression of Change scale in 62% of the cannabidiol group as compared with 34% of the placebo group (P=0.02). The frequency of total seizures of all types was significantly reduced with cannabidiol (P=0.03), but there was no significant reduction in nonconvulsive seizures. The percentage of patients who became seizure-free was 5% with cannabidiol and 0% with placebo (P=0.08). Adverse events that occurred more frequently in the cannabidiol group than in the placebo group included diarrhea, vomiting, fatigue, pyrexia, somnolence, and abnormal results on liver-function tests. There were more withdrawals from the trial in the cannabidiol group. Conclusions Among patients with the Dravet syndrome, cannabidiol resulted in a greater reduction in convulsive-seizure frequency than placebo and was associated with higher rates of adverse events. (Funded by GW Pharmaceuticals; number, NCT02091375.)
Oxidative stress, leukocyte infiltration and increased expression of intercellular adhesion molecule 1 (ICAM-1) in the colon are the most important factors in inflammatory bowel disease. The goal of the current study was to investigate the effects of adelmidrol, an analogue of the anti-inflammatory fatty acid amide signaling molecule palmitoylethanolamide, in mice subjected to experimental colitis. Additionally, in order to clarify if the protective action of adelmidrol is dependent on activation of peroxisome proliferator-activated receptors (PPARs), we investigated the effects of a PPAR-γ antagonist, GW9662, on adelmidrol action. Adelmidrol (10 mg/kg daily o.s.) was tested in a mouse experimental model of colitis induced by intracolonic administration of dinitrobenzene sulfonic acid. Nuclear factor-κB translocation, cyclooxygenase-2 and phospho-extracellular signal-regulated kinase as well as tumor necrosis factor-α and interleukin-1β were significantly increased in colon tissues after dinitrobenzene sulfonic acid administration. Immunohistochemical staining for ICAM-1, P-selectin, nitrotyrosine and poly(ADP)ribose showed a positive staining in the inflamed colon. Treatment with adelmidrol decreased diarrhea, body weight loss and myeloperoxidase activity. Adelmidrol treatment, moreover, reduced nuclear factor-κB translocation, cyclooxygenase-2 and phospho-extracellular signal-regulated kinase expression, pro-inflammatory cytokine release, the incidence of nitrotyrosine and poly(ADP)ribose in the colon and decreased the up-regulation of ICAM-1 and P-selectin. Adelmidrol treatment produced a reduction of Bax and an intensification of Bcl-2 expression. This study clearly demonstrates that adelmidrol exerts important anti-inflammatory effects that are partly dependent on PPAR-γ, suggesting that this molecule may represent a new pharmacological approach for inflammatory bowel disease treatment.