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Stable Gastric Pentadecapeptide BPC
157 Therapy for Primary Abdominal
Compartment Syndrome in Rats
Marijan Tepes
1
,
2
,
3
,
4
, Slaven Gojkovic
4
, Ivan Krezic
4
, Helena Zizek
4
, Hrvoje Vranes
4
,
Zrinko Madzar
5
, Goran Santak
6
, Lovorka Batelja
7
, Marija Milavic
7
, Suncana Sikiric
7
,
Ivica Kocman
4
, Karol Simonji
8
, Mariam Samara
4
, Mario Knezevic
4
, Ivan Barisic
4
, Eva Lovric
7
,
Sanja Strbe
4
, Antonio Kokot
9
, Ivica Sjekavica
10
, Toni Kolak
11
, Anita Skrtic
7
*, Sven Seiwerth
7
,
Alenka Boban Blagaic
4
and Predrag Sikiric
4
*
1
Department of Surgery, General Hospital Nasice, Nasice, Croatia,
2
Department of Clinical Medicine, Faculty of Dental Medicine
and Health Osijek, Zagreb, Croatia,
3
PhD Program Translational Research in Biomedicine –TRIBE, School of Medicine, University
of Split, Zagreb, Croatia,
4
Department of Pharmacology, School of Medicine, University of Zagreb, Zagreb, Croatia,
5
Clinical
Department of Surgery, Sestre Milosrdnice University Hospital Center, Zagreb, Croatia,
6
Department of Surgery, Faculty of
Medicine, University of Osijek, Osijek, Croatia,
7
Department of Pathology, School of Medicine, University of Zagreb, Zagreb,
Croatia,
8
Internal Diseases Clinic, Faculty of Veterinary Medicine Zagreb, Zagreb, Croatia,
9
Department of Anatomy and
Neuroscience, Faculty of Medicine, J.J. Strossmayer University of Osijek, Osijek, Croatia,
10
Department of Diagnostic and
Interventional Radiology, University Hospital Centre, Zagreb, Croatia,
11
Department of Surgery, School of Medicine, University of
Zagreb, Zagreb, Croatia
Recently, the stable gastric pentadecapeptide BPC 157 was shown to counteract major vessel
occlusion syndromes, i.e., peripheral and/or central occlusion, while activating particular
collateral pathways. We induced abdominal compartment syndrome (intra-abdominal
pressure in thiopental-anesthetized rats at 25 mmHg (60 min), 30 mmHg (30 min),
40 mmHg (30 min), and 50 mmHg (15 min) and in esketamine-anesthetized rats (25 mmHg
for 120 min)) as a model of multiple occlusion syndrome. By improving the function of the
venous system with BPC 157, we reversed the chain of harmful events. Rats with intra-
abdominal hypertension (grade III, grade IV) received BPC 157 (10 µg or 10 ng/kg sc) or saline
(5 ml) after 10 min. BPC 157 administration recovered the azygos vein via the inferior–superior
caval vein rescue pathway. Additionally, intracranial (superior sagittal sinus), portal, and caval
hypertension and aortal hypotension were reduced, as were the grossly congested stomach
and major hemorrhagic lesions, brain swelling, venous and arterial thrombosis, congested
inferior caval and superior mesenteric veins, and collapsed azygos vein; thus, the failed collateral
pathway was fully recovered. Severe ECG disturbances (i.e., severe bradycardia and ST-
elevation until asystole) were also reversed. Microscopically, transmural hyperemia of the
gastrointestinal tract, intestinal mucosa villi reduction, crypt reduction with focal denudation of
superficial epithelia, and large bowel dilatation were all inhibited. In the liver, BPC 157 reduced
congestion and severe sinusoid enlargement. In the lung, a normal presentation was observed,
with no alveolar membrane focal thickening and no lung congestion or edema, and severe intra-
alveolar hemorrhage was absent. Moreover, severe heart congestion, subendocardial
infarction, renal hemorrhage, brain edema, hemorrhage, and neural damage were
prevented. In conclusion, BPC 157 cured primary abdominal compartment syndrome.
Keywords: gastric pentadecapeptide BPC 157, primary abdominal compartment syndrome, rats, brain edema, lung
edema
Edited by:
Fan Jiang,
Shandong University, China
Reviewed by:
Dechang Chen,
Shanghai Jiao Tong University, China
Ying Li,
Xi’an Jiaotong University, China
*Correspondence:
Predrag Sikiric
sikiric@mef.hr
Anita Skrtic
skrtic.anita@gmail.com
Specialty section:
This article was submitted to
Translational Pharmacology,
a section of the journal
Frontiers in Pharmacology
Received: 09 June 2021
Accepted: 17 November 2021
Published: 13 December 2021
Citation:
Tepes M, Gojkovic S, Krezic I, Zizek H,
Vranes H, Madzar Z, Santak G,
Batelja L, Milavic M, Sikiric S,
Kocman I, Simonji K, Samara M,
Knezevic M, Barisic I, Lovric E, Strbe S,
Kokot A, Sjekavica I, Kolak T, Skrtic A,
Seiwerth S, Boban Blagaic A and
Sikiric P (2021) Stable Gastric
Pentadecapeptide BPC 157 Therapy
for Primary Abdominal Compartment
Syndrome in Rats.
Front. Pharmacol. 12:718147.
doi: 10.3389/fphar.2021.718147
Frontiers in Pharmacology | www.frontiersin.org December 2021 | Volume 12 | Article 7181471
ORIGINAL RESEARCH
published: 13 December 2021
doi: 10.3389/fphar.2021.718147
INTRODUCTION
We suggest that abdominal compartment syndrome (Depauw
et al., 2019) is a multiple occlusion syndrome. Therefore, it is
thought that by improving the function of the venous system with
the stable gastric pentadecapeptide BPC 157 (Vukojevic et al.,
2018;Gojkovic et al., 2020;Kolovrat et al., 2020;Gojkovic et al.,
2021a;Knezevic et al., 2021a;Knezevic et al., 2021a;Gojkovic
et al., 2021b;Knezevic et al., 2021b;Strbe et al., 2021), the chain of
harmful events in abdominal compartment syndrome can be
reversed.
The stable gastric pentadecapeptide BPC 157 was chosen and
tested in this study due to its beneficial effects in major vessel
occlusion syndromes (Vukojevic et al., 2018;Gojkovic et al., 2020;
Kolovrat et al., 2020;Gojkovic et al., 2021a;Knezevic et al., 2021a;
Knezevic et al., 2021a;Gojkovic et al., 2021b;Knezevic et al.,
2021b;Strbe et al., 2021) and as a prototypic cytoprotective
peptide (for review, see Sikiric et al., 1993a;Sikiric et al., 2006;
Sikiric et al., 2010;Sikiric et al., 2011;Sikiric et al., 2012;Sikiric
et al., 2013;Sikiric et al., 2014;Sikiric et al., 2016;Sikiric et al.,
2017;Sikiric et al., 2018;Sikiric et al., 2020a;Sikiric et al., 2020b;
Seiwerth et al., 2014;Seiwerth et al., 2018;Seiwerth et al., 2021;
Kang et al., 2018;Park et al., 2020;Gwyer et al., 2019,Vukojevic
et al., 2022).
To fully model intra-abdominal hypertension syndrome
(continuous intraperitoneal insufflation of ordinary air), these
occlusion syndromes have been induced peripherally (Vukojevic
et al., 2018;Gojkovic et al., 2020;Kolovrat et al., 2020;Knezevic
et al., 2021a;Knezevic et al., 2021a;Knezevic et al., 2021b)or
centrally (Gojkovic et al., 2021a) and both peripherally and
centrally (Gojkovic et al., 2021b;Strbe et al., 2021). Specific
occlusion syndrome induction can be performed by the
occlusion of a major vein (Vukojevic et al., 2018;Gojkovic
et al., 2020;Gojkovic et al., 2021a;Knezevic et al., 2021b)or
an artery (Knezevic et al., 2021a), or with both artery and vein
occlusion (Kolovrat et al., 2020;Knezevic et al., 2021a), or by
intragastric application of absolute alcohol (Gojkovic et al.,
2021b) and intraperitoneal application of lithium overdose
(Strbe et al., 2021).
Considering the effects of BPC 157 therapy peripherally and
centrally (Vukojevic et al., 2018;Gojkovic et al., 2020;Kolovrat
et al., 2020;Gojkovic et al., 2021a;Knezevic et al., 2021a;Knezevic
et al., 2021a;Gojkovic et al., 2021b;Knezevic et al., 2021b;Strbe
et al., 2021), in rats with severely increased intra-abdominal
pressure, i.e., primary abdominal compartment syndrome, we
attempted to introduce a therapy for compressed essential vessel
tributaries, both arterial and venous (peripherally and centrally),
due to occluded major veins and arteries, in order to prevent the
consequent noxious syndrome, both peripherally and centrally.
Otherwise, intra-abdominal hypertension adversely affects many
organs, such as the brain, heart, lungs, kidneys, and
gastrointestinal tract (Cullen et al., 1989), progressing to lethal
levels. As abdominal compartment syndrome leads to organ
failure at an intra-abdominal pressure of 20 mmHg (Hunter
and Damani, 2004;Hedenstierna and Larsson, 2012), to assess
the degree of severity that can be treated with this therapy, higher
intra-abdominal pressures of 25, 30, 40, and 50 mmHg were also
used. It was found that systemic and splanchnic blood flow and
afferent hepatic flow were reduced as the intra-abdominal
pressure rose; i.e., liver blood flow decreased by 39% when
pneumoperitoneum increased from 10 to 15 mmHg and liver
ischemic injury occurred (Chen et al., 2017).
Furthermore, as an immediate effect, the abdominal, thoracic,
and cranial cavities interact with each other (Depauw et al., 2019),
and increased intra-abdominal pressure causes an increase in
intracranial pressure (Malbrain and Wilmer, 2007;Scalea et al.,
2007;Youssef et al., 2012;Chen et al., 2020). Increased intra-
abdominal pressure also increases intrathoracic pressure, which is
rapidly transmitted up through the venous system, thereby
further increasing intracranial pressure (Malbrain and Wilmer,
2007;Scalea et al., 2007;Youssef et al., 2012;Chen et al., 2020).
Thus, although not specifically indicated, these findings support
the rapid improvement of venous system function as an essential
common point to prevent and reverse the noxious chain of events
and attenuate all harmful consequences.
Thus, it may be that maintained increased intra-abdominal
pressure causes widespread dysfunction, which would be similar
to the severe syndromes observed in rats with the occlusion of
peripheral vessels (Vukojevic et al., 2018;Gojkovic et al., 2020;
Kolovrat et al., 2020;Knezevic et al., 2021a;Knezevic et al., 2021a;
Knezevic et al., 2021b) and central vessels (Gojkovic et al., 2021a)
or after the intragastric application of absolute alcohol (Gojkovic
et al., 2021b) and intraperitoneal application of the lithium
overdose (Strbe et al., 2021). These peripheral and central
deficits can include severe gastrointestinal lesions, intracranial
(superior sagittal sinus) hypertension, brain swelling and lesions,
portal and caval hypertension, aortic hypotension, peripheral and
central thrombosis, inferior caval vein and superior mesenteric
vein congestion, azygos vein failure, electrocardiogram (ECG)
disturbances, and heart, lung, liver, and kidney lesions (Vukojevic
et al., 2018;Gojkovic et al., 2020;Kolovrat et al., 2020;Gojkovic
et al., 2021a;Knezevic et al., 2021a;Knezevic et al., 2021a;
Gojkovic et al., 2021b;Knezevic et al., 2021b;Strbe et al.,
2021). Syndrome development and treatment with BPC 157
have been demonstrated in a variety of procedures inducing
vessel occlusion (Vukojevic et al., 2018;Gojkovic et al., 2020;
Kolovrat et al., 2020;Gojkovicc et al., 2021a;Knezevic et al.,
2021a;Knezevic et al., 2021a;Gojkovic et al., 2021b;Knezevic
et al., 2021b;Strbe et al., 2021). These syndromes, specifically
those induced by vessel occlusion and subsequently treated with
BPC 157, include inferior caval vein syndrome (Vukojevic et al.,
2018), Pringle maneuver ischemia, reperfusion (Kolovrat et al.,
2020), Budd–Chiari syndrome (Gojkovic et al., 2020), superior
sagittal sinus occlusion (Gojkovic et al., 2021a), and superior
mesenteric artery and/or vein occlusion (Knezevic et al., 2021a;
Knezevic et al., 2021a;Knezevic et al., 2021b). The bypassing
loops appear to be reliant on the corresponding injurious
occlusion and reestablish blood flow to compensate for vessel
occlusion and to reduce syndrome severity (Vukojevic et al., 2018;
Gojkovic et al., 2020;Kolovrat et al., 2020;Gojkovic et al., 2021a;
Knezevic et al., 2021a;Knezevic et al., 2021a;Gojkovic et al.,
2021b;Knezevic et al., 2021b;Strbe et al., 2021). Previously, we
showed this for the left ovarian vein (i.e., inferior caval vein
syndrome (Vukojevic et al., 2018)), the inferior mesenteric vein in
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Tepes et al. BPC 157 and Abdominal Compartment Syndrome
the portocaval shunt (Kolovrat et al., 2020), and the azygos vein in
the superior-inferior caval vein shunt (Gojkovic et al., 2020;
Gojkovic et al., 2021a;Gojkovic et al., 2021b;Strbe et al.,
2021). More specifically, the superior mesenteric vein, inferior
and superior anterior pancreaticoduodenal, pyloric vein, and
portal vein in the superior mesenteric vein-portal vein shunt
reestablish the interrupted superior mesenteric and portal vein
pathway (the occluded end of the superior mesenteric vein)
(Knezevic et al., 2021b). The inferior mesenteric artery and
inferior anterior pancreaticoduodenal artery are alternative
pathways in the case of an occluded superior mesenteric artery
(Knezevic et al., 2021a). With simultaneous occlusion of both
superior mesenteric vessels, i.e., the artery and the vein, both
pathways, arterial and venous, are activated (Knezevic et al.,
2021a). Centrally (para)sagittal venous collateral circulation
appears with an occluded superior sagittal sinus (Gojkovic
et al., 2021a). It has been theorized that BPC 157 therapy
could likely represent a “bypassing key,”by rapidly activating
bypassing pathways and abrogating the complex syndrome
induced by simultaneous occlusion of essential arterial and
venous tributaries. Likewise, it has been theorized that this
“bypassing key”appears to be an effect of the essential
endothelial protective capacity of BPC 157. BPC 157, as a
novel and relevant cytoprotective mediator, rapidly activates
collateral bypassing pathways and alleviates vessel occlusion
syndromes (Vukojevic et al., 2018;Gojkovic et al., 2020;
Kolovrat et al., 2020;Gojkovic et al., 2021a;Knezevic et al.,
2021a;Knezevic et al., 2021a;Gojkovic et al., 2021b;Knezevic
et al., 2021b;Strbe et al., 2021). As such, with BPC 157 therapy,
endothelial protection (as a shared effect of cytoprotective agents
(Robert, 1979;Szabo et al., 1985)) and the cytoprotection theory
maxim “endothelium maintenance →epithelium maintenance”
(Robert, 1979;Szabo et al., 1985) may have additional
significance. Namely, Robert’s and Szabo’s original maxim
(“endothelium maintenance →epithelium maintenance”) may
be further promoted. Therefore, we reported evidence about
blood vessel recruitment and activation (“running”) toward
the site of injury, also described as bypassing occlusion via
alternative pathways (Vukojevic et al., 2018;Gojkovic et al.,
2020;Kolovrat et al., 2020;Gojkovic et al., 2021a;Knezevic
et al., 2021a;Knezevic et al., 2021a;Gojkovic et al., 2021b;
Knezevic et al., 2021b;Strbe et al., 2021). Consequently,
compensatory activated collateral blood vessels and
reorganized blood flow following BPC 157 treatment in rats
with the occluded major peripheral vessel(s) or central vessels
reduced superior sagittal sinus, portal and caval hypertension,
aortal hypotension, progressive venous and arterial thrombosis
peripherally and centrally, and ECG disturbances. Markedly,
multiple organ lesions in the heart, lung, liver, kidney, and
gastrointestinal tract, in particular, as well as brain lesions,
were attenuated, and oxidative stress was reduced in tissues
(Vukojevic et al., 2018;Gojkovic et al., 2020;Kolovrat et al.,
2020;Gojkovic et al., 2021a;Knezevic et al., 2021a;Knezevic et al.,
2021a;Knezevic et al., 2021b;Strbe et al., 2021).
The many blood vessels identified as being activated by specific
pathways following a given vessel injury require a regularly
applicable therapy, with beneficial effects dependent on, but
not limited to, occlusion of a particular vessel (Sikiric et al.,
2018). With BPC 157 therapy, this point was envisaged by the
consistent reduction of the whole “occlusive-like”syndrome that
regularly follows the intragastric application of absolute alcohol
in rats (Gojkovic et al., 2021b) and intraperitoneal application of
the lithium overdose (Strbe et al., 2021). Consequently, we
observed that this beneficial effect, after direct injury
(permanent ligation) applied to one or two major vessels,
could instantly oppose more general damage (maintained
intra-abdominal hypertension, either high (grade III) or very
high (grade IV)), as all blood vessels which can be compressed
with increased intra-abdominal pressure. Therefore, a “bypassing
key,”i.e., an activated azygos vein as a rescuing pathway, avoiding
both the lung and liver and also noted in Budd–Chiari syndrome
(i.e., suprahepatic occlusion of the inferior caval vein) (Gojkovic
et al., 2020), combines the inferior caval vein and superior caval
vein via direct blood delivery. Thus, activated azygos vein shunt
could reorganize blood flow and instantly attenuate the
consequences of maintained high intra-abdominal pressure,
both peripherally and centrally.
BPC 157s endothelial effects and its function as a “bypassing
key”(Sikiric et al., 2018) are strongly supported by its interaction
with the nitric oxide (NO) system (for a review, see Sikiric et al.,
2014). The most recent demonstration of the impact of BPC 157
on vasomotor tone was carried out through BPC 157-specific
activation of the Src-caveolin-1-endothelial NO synthase (eNOS)
pathway (Hsieh et al., 2020). BPC 157 acts as a membrane
stabilizer and free radical scavenger and reduces leaky gut
syndrome, as shown in gastrointestinal tract cytoprotective
studies (Park et al., 2020). BPC 157 also has a curative effect
due to interactions with several molecular pathways (Tkalcević
et al., 2007;Chang et al., 2011,2014;Huang et al., 2015;Hsieh
et al., 2017;Kang et al., 2018;Vukojevic et al., 2018;Wang et al.,
2019; Cesarec et al., 2013; Hsieh et al., 2020;Park et al., 2020;
Vukojevic et al., 2020;Wu et al., 2020).
Thus, we assessed BPC 157 therapy as a curative principle in
rats with established permanent intra-abdominal hypertension.
As confirmation, we used the crisis that occurred with the high
intra-abdominal pressure-induced syndrome, in which intra-
abdominal hypertension simultaneously affected all abdominal
vessels and organs for a considerable period and restrained the
ability to recruit alternative pathways, such that a deadly situation
was created before therapy initiation.
MATERIALS AND METHODS
Animals
This study was conducted with 12-week-old, 200 g body weight,
male Albino Wistar rats, randomly assigned at six rats/group/
interval. Rats were bred in-house at the Animal Pharmacology
Facility, School of Medicine, Zagreb, Croatia. The animal facility
is registered with the Veterinary Directorate (Reg. No: HR-POK-
007). Laboratory rats were acclimated for five days and randomly
assigned to their respective treatment groups. Laboratory animals
were housed in polycarbonate (PC) cages under conventional
laboratory conditions at 20–24°C, relative humidity of
Frontiers in Pharmacology | www.frontiersin.org December 2021 | Volume 12 | Article 7181473
Tepes et al. BPC 157 and Abdominal Compartment Syndrome
40–70%, and noise level of 60 dB. Each cage was identified
with dates, number of studies, group, dose, number, and sex of
each animal. Fluorescent lighting provided illumination 12 h
per day. Standard good laboratory practice (GLP) diet and
fresh water were provided ad libitum.Animalcarewasin
compliance with standard operating procedures (SOPs) of the
Animal Pharmacology Facility and the European Convention
for the Protection of Vertebrate Animals used for
Experimental and Other Scientific Purposes (ETS 123).
This study was approved by the local ethics committee. Ethical
principles of the study complied with the European Directive 010/
63/E, the Law on Amendments to the Animal Protection Act
(Official Gazette 37/13), the Animal Protection Act (Official
Gazette 135/06), the ordinance on the protection of animals
used for scientific purposes (Official Gazette 55/13), Federation
of European Laboratory Animal Science Associations (FELASA)
recommendations, and the recommendations of the Ethics
Committee of the School of Medicine, University of Zagreb.
The experiments were assessed by observers blinded as to the
treatment.
Drugs
Medication was administered as described previously
(Vukojevic et al., 2018;Gojkovic et al., 2020;Kolovrat
et al., 2020;Gojkovic et al., 2021a;Knezevic et al., 2021a;
Knezevic et al., 2021a;Gojkovic et al., 2021b;Knezevic et al.,
2021b), without the use of a carrier or peptidase inhibitor, for
stable gastric pentadecapeptide BPC 157 (10 µg or 10 ng/kg
subcutaneously), a partial sequence of the human gastric juice
protein BPC, which is freely soluble in water at pH 7.0 and in
saline. BPC 157 (GEPPPGKPADDAGLV, molecular weight
1,419; Diagen, Slovenia) was prepared as a peptide with 99%
high-performance liquid chromatography (HPLC) purity,
with 1-des-Gly peptide being the main impurity. The dose
and application regimens were as described previously (Duzel
et al., 2017;Amic et al., 2018;Drmic et al., 2018;Vukojevic
et al., 2018;Sever et al., 2019;Cesar et al., 2020;Gojkovic et al.,
2020;Kolovrat et al., 2020;Vukojevic et al., 2020).
Experimental Protocol
In deeply anesthetized rats (intraperitoneal (ip) injected
40 mg/kg thiopental (Rotexmedica, Germany) and 10 mg/kg
diazepam (Apaurin; Krka, Slovenia)), we induced abdominal
compartment syndrome by intraperitoneal insufflation of
ordinary air controlled by a manual and digital manometer
with a data logger connected to a computer (DD890,
Dostmann Electronic GmbH, Germany) and maintained
high abdominal pressure at 25 mmHg for 120 min before
sacrifice, with a pressure measurement interval of 1 s. High
abdominal pressure at 25, 30, 40, or 50 mmHg was maintained
until sacrifice at 60 min (25 mmHg), 30 min (30 mmHg,
40 mmHg), or 15 min (50 mmHg). Rats received BPC 157
(10µgor10ng/kgsubcutaneously)orsaline(5ml)at10min
abdominal compartment syndrome-time. Alternatively, using
esketamine anesthesia (40 mg/kg esketamine (Rotexmedica,
Germany) and 10 mg/kg diazepam (Apaurin; Krka, Slovenia)
intraperitoneally), we induced abdominal compartment
syndrome as described before and maintained high
abdominal pressure at 25 mmHg for 120 min before
sacrifice. Medication (BPC 157 (10 µg or 10 ng/kg sc) or
saline (5 ml)) was given after 10 min of high abdominal
pressure.
Recordings of brain swelling were performed in rats before
sacrifice after complete calvariectomy was performed
(Gojkovic et al., 2021a;Knezevic et al., 2021a;Knezevic
et al., 2021a;Knezevic et al., 2021b). Briefly, six burr holes
were drilled in three horizontal lines, all of them medially to
the superior temporal lines and temporalis muscle
attachments. The two rostral burr holes were placed just
basal from the posterior interocular line, the two basal burr
holes were placed just rostral to the lambdoid suture (and
transverse sinuses) on both sides, respectively, and the two
middle burr holes were placed in line between the basal and
rostral burr holes.
Rats were laparatomized before sacrifice for the
corresponding presentation of the peripheral vessels
(azygos vein, superior mesenteric vein, portal vein, inferior
caval vein, and abdominal aorta). The recording was
performed with a camera attached to a VMS-004 Discovery
Deluxe USB microscope (Veho, United States) at the end of
the experiment and assessed as before (Gojkovic et al., 2021a;
Knezevic et al., 2021a;Knezevic et al., 2021a;Knezevic et al.,
2021b;Strbe et al., 2021).
Superior Sagittal Sinus, Portal, Superior
Mesenteric, and Caval Vein, and Abdominal
Aorta Pressure Recording
As described before (Vukojevic et al., 2018;Gojkovic et al.,
2020;Kolovrat et al., 2020;Gojkovic et al., 2021a;Knezevic
et al., 2021a;Knezevic et al., 2021a;Gojkovic et al., 2021b;
Knezevic et al., 2021b;Strbe et al., 2021), recordings were
made in deeply anesthetized rats with a cannula (BD
Neoflon™Cannula) connected to a pressure transducer
(78534C MONITOR/TERMINAL; Hewlett Packard,
United States), inserted into the portal vein, inferior caval
vein, and superior sagittal sinus, as well as the abdominal
aorta at the level of the bifurcation at 15, 30, 60, or 120 min
ACS-time. For superior sagittal sinus pressure recording, we
made a single burr hole in the rostral part of the sagittal
suture, above the superior sagittal sinus, and cannulated the
superior sagittal sinus anterior part using a Braun intravenous
cannula; then, we laparatomized the rat for portal
vein, inferior vena cava, and abdominal aorta pressure
recording.
Notably, normal rats exhibited a superior sagittal sinus pressure of
−24 to −27 mmHg and superior mesenteric pressure and portal
pressure of 3–5 mmHg similar to that of the inferior vena cava,
though with values at least 1 mmHg higher in the portal vein. By
contrast, abdominal aorta blood pressure values were
100–120 mm Hg at the level of the bifurcation (Vukojevic et al.,
2018;Gojkovic et al., 2020;Kolovrat et al., 2020;Gojkovic et al., 2021a;
Knezevic et al., 2021a;Knezevic et al., 2021a;Gojkovic et al., 2021b;
Knezevic et al., 2021b;Strbe et al., 2021).
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Tepes et al. BPC 157 and Abdominal Compartment Syndrome
ECG Recording
ECGs were recorded continuously in deeply anesthetized rats for
all three main leads, by positioning stainless steel electrodes on all
four limbs using an ECG monitor with a 2090 programmer
(Medtronic, United States) connected to a Waverunner LT342
digital oscilloscope (LeCroy, United States) at 30 min ligation
time. This arrangement enabled precise recordings,
measurements, and analysis of ECG parameters (Vukojevic
et al., 2018;Gojkovic et al., 2020;Kolovrat et al., 2020;
Gojkovic et al., 2021a;Knezevic et al., 2021a;Knezevic et al.,
2021a;Gojkovic et al., 2021b;Knezevic et al., 2021b;Strbe et al.,
2021). The time until extreme bradycardia and asystole was
assessed.
Thrombus Assessment
Following sacrifice, the superior sagittal sinus and peripherally
the portal vein, external jugular vein, inferior caval vein, superior
mesenteric vein, hepatic vein, superior mesenteric artery, hepatic
artery, and abdominal aorta were removed from the rats, and the
clots were weighed (Vukojevic et al., 2018;Gojkovic et al., 2020;
Kolovrat et al., 2020;Gojkovic et al., 2021a;Knezevic et al., 2021a;
Knezevic et al., 2021a;Gojkovic et al., 2021b;Knezevic et al.,
2021b;Strbe et al., 2021).
Brain Volume and Vessel Presentation
Brain volume and vessel presentation were proportional to the
change in the brain or vessel surface area. The presentation of
the brain and peripheral vessels (superior mesenteric vein,
portal vein, inferior caval vein, azygos vein, and abdominal
aorta) was recorded in deeply anesthetized rats, with a camera
attached to a VMS-004 Discovery Deluxe USB microscope
(Veho, United States) (Gojkovic et al., 2021a;Knezevic et al.,
2021a;Knezevic et al., 2021a;Gojkovic et al., 2021b;Knezevic
et al., 2021b;Strbe et al., 2021).Theborderofthebraininthe
image was marked using ImageJ software and then the surface
area of the brain was measured. This was done with brain
images for both the control (saline) group and treated (BPC
157) group of rats at same intervals after the application and at
the time of sacrifice. The arithmetic mean of the surface areas
was calculated for both groups. Then, the ratio of these two
areas was calculated as (Acon
Abpc), where A
con
is the arithmetic
mean brain area of the control group and A
bpc
is the
arithmetic mean brain area of the treated group. Starting
from the square-cube law equations [1] [2],anequationfor
the change in brain volume proportional to the change in
brain surface area [6] was derived. In expressions [1–5], lis
defined as any arbitrary one-dimensional length of the brain
(for example, rostrocaudal length of the brain), used only for
defining the one-dimensional proportion (l
2
/l
1
) between two
observed brains and as an inter-factor (and because of that not
measured [6])forderivingfinal expression [6]. The procedure
wasasfollows: A
2A1×(
l2
l1)2[1] (square-cube law), V2
V1×(
l2
l1)3[2] (square-cube law), A2
A1(
l2
l1)2[3] (from [1], after
dividing both sides by A
1
), l2
l1
A2
A1
[4] (from [3],aftertaking
the square root of both sides), V2
V1(
l2
l1)3[5] (from [2], after
dividing both sides by V
1
), and V2
V1(
A2
A1
)3[6] (after
incorporating expression [4] into equation [5]).
Gross Assessment of Gastrointestinal
Lesions
A camera attached to a VMS-004 Discovery Deluxe USB
microscope (Veho, United States) was used for recording. In
deeply anesthetized rats, laparatomized before sacrifice, we
assessed the gross lesions in the gastrointestinal tract and in
the stomach (sum of the longest diameters, mm) (Gojkovic et al.,
2020;Kolovrat et al., 2020;Gojkovic et al., 2021a;Knezevic et al.,
2021a;Knezevic et al., 2021a;Gojkovic et al., 2021b;Knezevic
et al., 2021b;Strbe et al., 2021).
Liver and Spleen Weights
Liver and spleen weights are expressed as a percentage of total
body weight (for normal rats, liver, 3.2–4.0%; spleen,
0.20–0.26%).
MICROSCOPY
From rats, at end of the experiment, the brain, liver, kidney,
stomach, duodenum, jejunum, colon, rectum, lungs, and heart
were fixed in 10% neutral buffered formalin (pH 7.4) at room
temperature for 24 h. Representative tissue specimens were
embedded in paraffin, sectioned at 4 μm, stained with
hematoxylin and eosin (H&E), and evaluated by light
microscopy using an Olympus 71 digital camera and an
Olympus BX51 microscope (Japan) acquiring digital images
saved as uncompressed 24-bit RGB TIFF files.
Analysis of Central Nervous System
Karyopyknotic Cells
Modified Bielschowsky’s silver staining and Klüver–Barrera staining
(using Klüver–Barrera Luxol fast blue) were performed to
demonstrate argentophilic neurites, axonal spheroids, and neuronal
cell bodies, particularly in brain karyopyknotic areas (https://journals.
sagepub.com/doi/pdf/10.1038/jcbfm.1995.128) (file:///F:/ACS%
20manuscript/CVI_rat_phd_nedergaard1987.pdf).
The brain was dissected according to NTP-7 at Levels 3 and 6
with neuroanatomic subsites presented in certain brain sections
using coronal sections with three mandatory sections (Eustis
et al., 2017;Gojkovic et al., 2021a;Knezevic et al., 2021a;
Knezevic et al., 2021a;Gojkovic et al., 2021b;Knezevic et al.,
2021b;Strbe et al., 2021) and analyzed using a semiquantitative
neuropathological scoring system, as previously described (Bona
et al., 1998;Gojkovic et al., 2021a;Knezevic et al., 2021a;Knezevic
et al., 2021a;Gojkovic et al., 2021b;Knezevic et al., 2021b;Strbe
et al., 2021), the and combined score (0–8) the sum of the
analyzed affected areas (0–4) and karyopyknotic cells in the brain
areas (0–4), as follows. Specifically, analyzed were the affected
brain areas (0–4), cerebral (NTP-7, Level 3), cerebellar cortex
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Tepes et al. BPC 157 and Abdominal Compartment Syndrome
(NTP-7, Level 6), and hippocampus, thalamus, and
hypothalamus (NTP-7, Level 3) as follows (score 0 indicates
no histopathologic change): score 1: small, patchy, complete, or
incomplete infarcts (≤10% of the area affected); score 2: partly
confluent or incomplete infarcts (20–30% of the area affected);
score 3: large confluent complete infarcts (40–60% of the area
affected); score 4: in cortex total disintegration of the tissue and
the hypothalamus, thalamus, and hippocampus large complete
infarcts (˃75% of the area affected). Analyzed were karyopyknotic
cells in the affected brain areas (0–4), cerebral (NTP-7, Level 3),
cerebellar cortex (NTP-7, Level 6), and hippocampus, thalamus,
and hypothalamus (NTP-7, Level 3) as follows (score 0 indicates
no change): score 1: a few karyopyknotic of neuronal cells
(≤20%); score 2: patchy areas of karyopyknotic cells (50%);
score 3: more extensive karyopyknotic areas (75%); score 4:
complete infarction (100%).
The neuronal pathological changes were also observed in the
acquired digital images saved as uncompressed 24-bit RGB TIFF
files in the software program AnalySIS (Olympus Soft Imaging
System GmbH, Münster, Germany) performing quantitative
analysis of neuronal damage in the karyopyknotic areas. The
neurons of the cortical cerebral, cerebellar region, hippocampus,
and hypothalamus were counted in 10 different high-powered
fields (HPF, 400x) and 3 to 5 serial sections of each sample were
used to do the count as described in https://www.ncbi.nlm.nih.
gov/pmc/articles/PMC5303860/. The field size was 0.24 μm
2
.
Lung histology. A scoring system was used to grade the degree
of lung injury in lung tissue analysis (Gojkovic et al., 2021a;
Knezevic et al., 2021a;Knezevic et al., 2021a;Gojkovic et al.,
2021b;Knezevic et al., 2021b). Features included focal thickening
of the alveolar membranes, congestion, pulmonary edema, intra-
alveolar hemorrhage, interstitial neutrophil infiltration, and
intra-alveolar neutrophil infiltration. Each feature was assigned
a score from 0 to 3 based on its absence (0) or presence to a mild
(1), moderate (2), or severe (3) degree, and a final histology score
was determined (Murao et al., 2003).
Renal, liver, and heart histology. The criteria renal injury was
based on the degeneration of Bowman’sspaceandglomeruli,
degeneration of the proximal and distal tubules, vascular
congestion, and interstitial edema (Gojkovic et al., 2021a;
Knezevic et al., 2021a;Knezevic et al., 2021a;Gojkovic et al.,
2021b;Knezevic et al., 2021b;Strbe et al., 2021). The criteria for
liver injury were vacuolization of hepatocytes and pyknotic
hepatocyte nuclei, activation of Kupffer cells, and enlargement
of sinusoids. Each specimen was scored using a scale ranging
0–3 (0: none; 1: mild; 2: moderate; 3: severe) for each criterion,
and a final histology score was determined (Ibrahim, et al.,
2010;Gojkovic et al., 2021a;Gojkovic et al., 2021b;Knezevic
et al., 2021a;Knezevic et al., 2021b;Knezevic et al., 2021a;Strbe
et al., 2021). Cardiac lesion estimation was based on the
dilatation and congestion of blood vessels within the
myocardium and coronary arteries using a scale ranging 0–3
(0: none; 1: mild; 2: moderate; 3: severe) (Gojkovic et al., 2021a;
Knezevic et al., 2021a;Knezevic et al., 2021a;Gojkovic et al.,
2021b;Knezevic et al., 2021b;Strbe et al., 2021).
Gastrointestinal histology. As previously described (Gojkovic
et al., 2020;Kolovrat et al., 2020;Gojkovic et al., 2021a;Knezevic
et al., 2021a;Knezevic et al., 2021a;Gojkovic et al., 2021b;
Knezevic et al., 2021b;Strbe et al., 2021), intestinal tissue
damage was analyzed using a histologic scoring scale
adapted from Chui and coworkers (Chui et al., 1970) on a
scale of 0–5 (normal to severe) in three categories (mucosal
injury, inflammation, and hyperemia/hemorrhage) for a total
score of 0–15, as described by Lane and coworkers (Lane et al.,
1997). Morphologic features of mucosal injury were based on
different grades of epithelial lifting, villi denudation, and
necrosis; grades of inflammation were graded from focal to
diffuse according to lamina propria infiltration or
subendothelial infiltration; hyperemia/hemorrhage was
graded from focal to diffuse according to lamina propria or
subendothelial localization. In addition, the villi height was
assessed as well (normal villi height as indicated before (Sever
et al., 2009;Teshfam et al., 2010)).
Statistical Analysis
Statistical analysis was performed by parametric one-way analysis
of variance (ANOVA), with the Newman–Keuls post hoc test or
the non-parametric Kruskal–Wallis test and subsequently the
Mann–Whitney Utest to compare groups. Values are presented
as the mean ±standard deviation (SD) and as the minimum/
median/maximum. To compare the frequency difference between
groups, the chi-squared test or Fischer’s exact test was used. p<
0.05 was considered statistically significant.
RESULTS
We revealed that, despite permanently increased intra-
abdominal hypertension (grade III and grade IV), a
perilous syndrome occurred peripherally and centrally, the
reversal of the abdominal compartment syndrome induced by
the stable gastric pentadecapeptide BPC 157 application was
quite consistent. With sustained increased intra-abdominal
pressures and pentadecapeptide BPC 157 application,
otherwise imminent abdominal compartment syndrome
(i.e., 25 mmHg or 30 mmHg, or 40 mmHg or 50 mmHg for
25, 30, and 60 min (thiopental) and for 120 min (esketamine))
did not appear. This was seen with the portal, caval, aortal,
and superior sagittal sinus pressure assessment, reduced
major ECG disturbances, nearly abrogated arterial and vein
thrombosis, and preserved presentation of the brain, heart,
lungs, liver, kidneys, and gastrointestinal tract, with no lethal
outcomes despite the permanent maintenance of high intra-
abdominal pressure. Both BPC 157 regimens (µg and ng)
provided a similar therapeutic effect in all of the
investigated protocols of abdominal compartment syndrome.
Commonly, all increased intra-abdominal pressures (i.e., 25,
30, 40, and 50 mmHg) produced a highly noxious syndrome,
which occurred both peripherally and centrally. This noxious
syndrome resembled the major vessel occlusion-induced
syndromes (Vukojevic et al., 2018;Gojkovic et al., 2020;
Kolovrat et al., 2020;Gojkovic et al., 2021a;Knezevic et al.,
2021a;Knezevic et al., 2021a;Knezevic et al., 2021b)or
“occlusion-like”syndromes that appear after intragastric
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Tepes et al. BPC 157 and Abdominal Compartment Syndrome
application of absolute alcohol (Gojkovic et al., 2021b) and
intraperitoneal application of lithium overdose (Strbe et al.,
2021), in particular, similar to the acute Budd–Chiari
syndrome and acute suprahepatic inferior caval vein occlusion
(Gojkovic et al., 2020). Contrarily, in rats with high intra-
abdominal pressure, the application of BPC 157 had a
considerable therapeutic effect. For this effect, in all BPC 157-
treated rats, the common key finding may be the rapidly activated
azygos vein collateral pathway, which combined the inferior caval
vein and left superior caval vein, to reverse the rapid presentation
of this deadly syndrome.
Blood Pressure Disturbances
Perceived as a cause-consequence relation, the important
evidence is that BPC 157 reduced blood pressure disturbances
that were induced by increased intra-abdominal pressures, shown
to be quite severe and noted peripherally (portal and caval
hypertension, aortal hypotension) as well centrally (superior
sagittal sinus hypertension) (Figure 1). The severely increased
pressure values in the portal vein, inferior caval vein, and superior
sagittal sinus, as well as the decreased pressure values in the
abdominal aorta, were markedly attenuated with BPC 157
application.
Collateral Pathways, Blood Vessels, and
Brain Gross Presentation
As a follow-up to the attenuation of blood pressure disturbances,
peripherally and centrally, there was a reduction in blood stasis by
activating the collateral pathway to compensate for major vessel
occlusion due to mechanical compression. Consequently, there were
particular effects of BPC 157 on the relative volume of the vessels and
FIGURE 1 | Blood pressure, mmHg (in the superior sagittal sinus (SSS), portal vein (PV), abdominal aorta (AA), inferior caval vein (ICV)), in the thiopental-
anesthetized rats with the increased intra-abdominal pressures at 50 mmHg for 25 min, at 30 mmHg or 40 mmHg for 30 min, and at 25 mmHg for 60 min increased
intra-abdominal pressures-time, and in the esketamine-anesthetized rats with the increased intra-abdominal pressures at the 25 mmHg for 120 min increased intra-
abdominal pressures-time, following medication (BPC 157 10 μg/kg (light gray bars), 10 ng/kg (dark gray bars); saline 5 ml/kg (white bars)) given subcutaneously at
10 min increased intra-abdominal pressures-time. Means ±SD, *P˂0.05, vs. control.
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Tepes et al. BPC 157 and Abdominal Compartment Syndrome
FIGURE 2 | Relative brain and vessels volume (volume control/volume BPC 157, %) in the thiopental-anesthetized rats with the increased intra-abdominal
pressures at 50 mmHg for 25 min,at 30 mmHg or 40 mmHg for30 min, andat 25 mmHg for 60 min increasedintra-abdominal pressures-time, andin the esketamine-
anesthetized rats with the increased intra-abdominal pressures at 25 mmHg for 120 min increased intra-abdominal pressures-time, following medication (BPC
157 10 μg/kg (light gray bars), 10 ng/kg (dark gray bars); saline 5 ml/kg (not shown, control/control as control, 100% for comparison)) given subcutaneously at
10 min increased intra-abdominal pressures-time. Means ±SD, *P˂0.05, vs. control.
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Tepes et al. BPC 157 and Abdominal Compartment Syndrome
brain that may be indicative of the activated defensive response
(Figures 2,3,4,5). BPC 157 may decrease the relative volume of the
superior mesenteric vein and inferior caval vein and brain (Figures
2,4,5). These veins appeared congested (Figures 3,4), likely due to
failed vessels and trapped blood volume (note that the liver and
spleen relative weights were increased, along with hemorrhagic
lesions in the stomach) (Figures 9,10)(Figures 3,4,5).
Evidently, as a particular effect on blood vessels, congestion was
reduced by activating the collateral bridging pathway, i.e., the azygos
vein (Figure 2), as BPC 157 increased the azygos vein relative
volume (Figures 2,4). In this way, BPC 157 combined the inferior
caval vein and left superior caval vein to reestablish blood flow.
Finally, regarding brain swelling and increased volume (associated
with considerable brain injuries) (Figures 2,5), BPC 157 rapidly
induced a considerable decrease toward normal brain presentation
(Figures 2,5).
Thrombosis
Likewise, in the cause-consequence course of the therapy, BPC
157 reduced thrombosis, both peripherally and centrally.
Without therapy, thrombosis imminently occurred along with
high intra-abdominal pressure, peripherally in veins (i.e., portal
vein and inferior caval vein, superior mesenteric vein, hepatic
veins, and external jugular vein) and in arteries (i.e., superior
mesenteric artery, hepatic artery and abdominal aorta) and
centrally (i.e., superior sagittal sinus) (Figure 6). Note that,
without therapy, while thrombosis was present in all
investigated vessels, with an initial increase of 25 mm, the
most prominent clots appeared in the hepatic veins. With
further pressure increases (30, 40, and 50 mmHg), clot
formation generally increased, and prominent clots also
appeared in the portal vein and inferior caval vein and in the
abdominal aorta.
FIGURE 3 | Illustrative presentation of the inferior caval vein (full arrows) and superior mesenteric vein (dashed arrows) after the increased intraabdominal pressure
and medication (sc) (saline (5 ml/kg) (white arrows, small letters, congested veins a, b, c) or BPC 157 (10 ng/kg) (black arrows, capitals, non-congested veins A, B, C):
25 mmHg (60 min) (a, A), 40 mmHg (30 min) (b, B), and 50 mmHg (30 min) (c, C). A camera attached to a VMS-004 Discovery Deluxe USB microscope (Veho,
United States).
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Tepes et al. BPC 157 and Abdominal Compartment Syndrome
Heart and ECG Disturbances
Commonly, high intra-abdominal pressures were timely along
with the nodal rhythm, with dominant ST-elevation and
bradycardia. Extreme bradycardia and asystole appeared as the
ultimate outcome, at 20 ±2 min (50 mmHg), 25 ±5 min and 28 ±
2 min (30 mmHg and 40 mmHg), and 55 ±8 min (25 mmHg) in
control rats under thiopental anesthesia and at 110 ±25 min in
esketamine-anesthetized control rats. However, the evidence
shows that despite continuously maintaining high intra-
abdominal pressure, in all BPC 157-treated rats, heart function
was consistently maintained, with fewer ECG disturbances. The
sinus rhythm was preserved, with occasional first-degree AV
block, but with no ST-elevation. Extreme bradycardia and
asystole were not observed. This occurred along with normal
heart microscopic presentation, unlike the myocardial congestion
and sub-endocardial infarction observed in controls (Figure 11).
Gastrointestinal, Lung, Liver, Kidney, and
Heart Lesions
Consequently, as part of the cause-consequence therapeutic
course, i.e., reduced intracranial (superior sagittal sinus),
portal, and caval hypertension, reduced aortal hypotension,
and activated collateral pathway, BPC 157 reduced the severity
of lesions in the gastrointestinal tract and other organs commonly
noted in the untreated rats with high intra-abdominal pressures
(Figures 7,8,9,10,11;Supplementary Figures S1, S2).
With an increase in severity from the upper toward the lower
part of the gastrointestinal tract, control rats demonstrated
transmural hyperemia of the entire gastrointestinal tract,
stomach, duodenum, and small and large bowel wall, along
with a reduction in the villi in the intestinal mucosa, crypt
reduction with focal denudation of superficial epithelia, and
dilatation of the large bowel (Figures 7,8,9,10,11;
Supplementary Figures S1, S2). Regularly, in BPC 157-treated
rats, we noted no or minimal congestion in the gastrointestinal
mucosa with well-preserved intestinal villi and colonic crypts
with no dilatation of the large bowel. Considering intra-
abdominal hypertension at grade III and grade IV and the
therapeutic effect, it was not surprising to find a considerable
decrease in villi height in all control rats with high intra-
abdominal pressure (Figures 7,9;Supplementary Figures S1,
S2) and preserved villi height in the BPC 157-treated rats (similar
to the villi height in healthy rats, indicating preserved intestinal
function despite high intra-abdominal pressure).
Without therapy, severe lesions were observed in the rats with
high intra-abdominal pressures, characterized by marked
congestion of the myocardium and subendocardial infarcts
(Figure 11), marked congestion and large areas of intra-
alveolar hemorrhage in the lung (Figure 10), vascular dilation
of the liver parenchyma (Figure 10), and renal congestion
(Figure 11). In contrast, as a result of treatment, the equally
high intra-abdominal pressures in BPC 157-treated rats led to
only mild congestion in the gastrointestinal tract, liver, and
kidney (Figures 7,8,9,10,11), particularly with high intra-
FIGURE 4 | Illustrative presentation of the azygos veins after the
increased intraabdominal pressure and medication (sc) (full white arrow, saline
(5 ml/kg, low, poor azygos vein presen tation a, b) or BPC 157 (full black arrow,
10 ng/kg, upper, functioning azygos vein A, B): 40 mmHg (30 min) (a, A)
and 50 mmHg (25 min) (b, B). Aorta (dashed arrows (white (control), black
(BPC 157), axillar vein (full yellow arrow), left superior caval vein (red arrow),
eternal jugular vein (dashed yellow arrow), internal jugular vein (dark yellow
dashed arrow). A camera attached to a VMS-004 Discovery Deluxe USB
microscope (Veho, United States).
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Tepes et al. BPC 157 and Abdominal Compartment Syndrome
abdominal pressures at 40 and 50 mmHg (otherwise, no changes
in the liver and renal parenchyma were observed). The
myocardium was preserved, with no change in the lung
parenchyma (Figure 8,10,11).
Brain Lesions, Cerebral and Cerebellar
Cortex, Hypothalamus/Thalamus, and
Hippocampus
Without therapy, the consistently downhill course of intra-
abdominal hypertension in rats with high intra-abdominal
pressures led to multiple organ lesions, widespread
thrombosis, disturbed ECG and blood pressure, portal and
caval hypertension, aortal hypotension, and, in particular,
intracranial (superior sagittal sinus) hypertension (Figures
1–15) along with severe brain lesions (Figures 12,13,14,15).
Moreover, evidently, the brain was consistently swollen (Figures
1,5), resulting in brain damage in all investigated areas (Figures
12,13,14,15).
In general, congestion of the cerebral and cerebellar cortex,
hypothalamus/thalamus, and hippocampus was observed,
with edema and large areas with increased numbers of
karyopyknotic cells, as well as intracerebral hemorrhage,
mostly in the infratentorial space, affecting the cerebello
angle/area (Figures 12,13,14,15). We noted an increased
number of karyopyknotic cells in all four regions, i.e., the
cerebral and cerebellar cortex, hippocampus, and
hypothalamus/thalamus (Figure 14). Especially, there was
karyopyknosis and degeneration of Purkinje cells of the
cerebellar cortex and marked karyopyknosis of pyramidal
cells in the hippocampus. In particular, these brain lesions
appeared to be distinctively affected by high intra-abdominal
pressure; i.e., the most progressive hippocampal neuronal
damage was found with the highest intra-abdominal
pressure. Contrarily, as a cause-consequence of BPC 157
therapy, i.e., reduced intracranial (superior sagittal sinus)
hypertension and gross brain swelling, along with reduced
portal and caval hypertension, aortal hypotension, abrogated
thrombosis, and an activated collateral pathway, these lesions
were largely reduced in BPC 157-treated rats, with a highly
protected cortex, hypothalamus/thalamus, and
hippocampus, as well as healthy Purkinje cells in the
FIGURE 5 | Illustrative brain presentation in the rats with the increased intra-abdominal pressure (50 mm Hg). In calvarial window (upper), at 15 min increased
pressure time and medication saline (5 ml/kg ip) (upper, left, control, a)or BPC 157 (10 ng/kg sc) (upper, right, A), at 10 min increased intra-a bdominal pressure time.
After sacrifice (low), at the 25 min increased intra-abdominal pressure time (saline (5 ml/kg ip) (low, left, control, b)or BPC 157 (10 ng/kg sc) (low, right, B)at 10 min
increased intra-abdominal pressure time. Prominent brain swelling in control rats (left), completely reversed in BPC 157 rats (right). A camera attached to a VMS-
004 Discovery Deluxe USB microscope (Veho, United States).
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Tepes et al. BPC 157 and Abdominal Compartment Syndrome
cerebellar cortex. BPC 157-treated rats showed a few
karyopyknotic neuronal cells in the analyzed
neuroanatomic structures.
Quantitative analysis of neuronal damage in the
karyopyknotic areas in all four neuroanatomic structures
showed no or only a few karyopyknotic neural cells
FIGURE 6 | Thrombus mass, g (in the superior sagittal sinus (SSS), portal vein (PV), inferior caval vein (ICV), superior mesenteric vein (SMV), external jugularvein
(EJV), hepatic veins (HV), abdominal aorta (AA), superior mesenteric artery (SMA) and hepatic artery (HA)) in the thiopental-anesthetized rats with the increased intra-
abdominal pressures at 50 mmHg for 25 min, at 30 mmHg or 40 mmHg for 30 min, at 25 mmHg for 60 min increased intra-abdominal pressures-time and in the
esketamine-anesthetized rats with the increased intra-abdominal pressures at 25 mmHg for 120 min increased intra-abdominal pressures-time, following
medication (BPC 157 10 μg/kg (light gray bars), 10 ng/kg (dark gray bars); saline 5 ml/kg (white bars)) given subcutaneously at 10 min increased intra-abdominal
pressures-time. Means ±SD, *P˂0.05, vs. control.
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Tepes et al. BPC 157 and Abdominal Compartment Syndrome
(Figure 12). The white matter was more vulnerable to chronic
cerebral injury. No white matter lesions were found in both
groups of animals using modified Bielschowsky silver staining
and Klüver–Barrera staining.
In summary, after BPC 157 therapy, rats with high intra-
abdominal pressures (grade III and grade IV) exhibited markedly
attenuated portal and caval hypertension, ameliorated aortal
hypotension, and markedly attenuated superior sagittal sinus
hypertension. Additionally, venous and arterial thrombosis was
attenuated, both peripherally and centrally, which markedly
mitigated stasis and moreover reduced brain, heart, lung, liver,
kidney, and gastrointestinal lesions as the untreated result. These
reductions were ascribed to the key finding of an activated
particular collateral pathway, i.e., the azygos vein, which
combined the inferior caval vein and left superior vein to
reorganize blood flow.
DISCUSSION
We investigated the reversal of abdominal compartment
syndrome induced by the stable gastric pentadecapeptide BPC
157 due to its previously observed therapeutic effect noted in
vessel occlusion syndromes (Vukojevic et al., 2018;Gojkovic
et al., 2020;Kolovrat et al., 2020;Gojkovic et al., 2021a;
Knezevic et al., 2021a;Knezevic et al., 2021a;Gojkovic et al.,
2021b;Knezevic et al., 2021b;Strbe et al., 2021).
With the applied procedure (i.e., 25, 30, 40, or 50 mmHg intra-
abdominal hypertension), there was a regular downhill chain of
events, regardless of the type of anesthesia (i.e., esketamine, as
ketamine is an antioxidant (Xingwei et al., 2014) that may provide
a more prolonged survival period than thiopental). The
abdominal wall compliance threshold was crossed
mechanically, with no further stretch of the abdomen; this
FIGURE 7 | Gastrointestinal lesions microscopy scoring (0–15), stomach, duodenum, jejunum, ascending colon and intestinal villi high, µm, and stomach lesions
(sum of longest lesions diameters, mm), relative liver weight (% of total body weight), relative spleen weight (% of total body weight) in the thiopental-anesthetized rats with
the increased intra-abdominal pressures at 50 mmHg for 25 min, at 30 mmHg or 40 mmHg for 30 min, at 25 mmHg for 60 min increased intra-abdominal pressures-
time, and in the esketamine-anesthetized rats with the increased intra-abdominal pressures at 25 mmHg for 120 min increased intra-abdominal pressures-time,
following medication (BPC 157 10 μg/kg (light gray bars), 10 ng/kg (dark gray bars); saline 5 ml/kg (white bars)) given subcutaneously at 10 min increased intra-
abdominal pressures-time. Minimum (min), maximum (max), median (med), means ±SD, *P˂0.05, vs. control.
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Tepes et al. BPC 157 and Abdominal Compartment Syndrome
FIGURE 8 | Organs (lung, liver, kidney, heart) microscopy scoring (0–3), in the thiopental-anesthetized rats with the increased intra-abdominal pressures at
50 mmHg for 25 min, at 30 mmHg or 40 mmHg for 30 min, at 25 mmHg for 60 min increased intra-abdominal pressures-time, and in the esketamine-anesthetized rats
with the increased intra-abdominal pressures at 25 mmHg for 120 min increased intra-abdominal pressures-time, following medication (BPC 157 10 μg/kg (light gray
bars), 10 ng/kg (dark gray bars); saline 5 ml/kg (white bars)) given subcutaneously at 10 min increased intra-abdominal pressures-time. Minimum (min), maximum
(max), median (med), *P˂0.05, vs. control. Figure 9. Illustrative presentation of gross and microscopic presentation. Gross presentation. Stomach (a, A) and liver (b,B)
(white letters) after the increased intraabdominal pressure and medication (sc) (saline (5 ml/kg, left, stomach and duodenum with multiple small hemorrhagic lesions (a),
and congested liver (b) presentation) or BPC 157 (10 ng/kg, right, stomach and duodenum, and liver A, B): 25 mmHg (30 min) (a, A) and 40 mmHg (30 min) (b, B). A
camera attached to a VMS-004 Discovery Deluxe USB microscope (Veho, United States). Microscopy presentation. Stomach (a, A) and colon (b, B) (black letters)
presentation inrats withthe increased intra-abdominal pressure at50 mmHg for25 min treatedat 10 minincreased intra-abdominalpressure timewith saline(control, a,
b) or BPC 157 (A, B). The control group showed marked hyperemia and congestion of the stom ach wall (a) and a reduction of the colonic crypts with focal denudation of
the superficial epithelia (b). BPC 157-treated rats exhibit presentation close to normal gastrointestinal tract presentation (A, B). (HE; a, A,magnification ×100, scale bar
200 μm; b, B,magnification ×200, scale bar 100 μm).
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Tepes et al. BPC 157 and Abdominal Compartment Syndrome
increased intra-abdominal pressure, compressed vessels and
organs, and pushed up the diaphragm as a predetermined
definitive outcome (Depauw et al., 2019). Abdominal
compartment syndrome appeared as a multiple occlusion
syndrome that could not be avoided unless therapy was given.
Regularly, reciprocal changes in the abdominal, thoracic, and
brain cavities (Depauw et al., 2019) rapidly appeared as
determinants of vascular failure. Therefore, in the rats with
intra-abdominal hypertension, multiorgan failure
(i.e., gastrointestinal, brain, heart, liver, and kidney lesions),
portal and caval hypertension, aortal hypotension, intracranial
(superior sagittal sinus) hypertension, and generalized
thrombosis appeared. This led to generalized stasis, generalized
Virchow triad presentation, and severe ECG disturbances;
therapy was able to provide adequate compensation
(i.e., activation of collateral pathways to reestablish blood
flow), both rapid and sustained, as demonstrated with BPC
157 therapy. As a prime and practical confirmation, rats with
major vessel ligation and occlusion, in either artery and/or vein,
and either peripherally or centrally, exhibited a similar syndrome
(Vukojevic et al., 2018;Gojkovic et al., 2020;Kolovrat et al., 2020;
Gojkovic et al., 2021a;Knezevic et al., 2021a;Knezevic et al.,
2021a;Knezevic et al., 2021b). Thus, there may be a shared
inability to react, leading to innate vascular failure upon major
vessel occlusion (ligation) (Vukojevic et al., 2018;Gojkovic et al.,
2020;Kolovrat et al., 2020;Gojkovic et al., 2021a;Knezevic et al.,
2021a;Knezevic et al., 2021a;Knezevic et al., 2021b) as well as
upon the induction of high intra-abdominal pressure, with all
vessels compressed. Likewise, with BPC 157 therapy, there may be
a shared curative effect, with consistent beneficial evidence in all
of the rats with major vessel occlusion (Vukojevic et al., 2018;
Gojkovic et al., 2020;Kolovrat et al., 2020;Gojkovic et al., 2021a;
Knezevic et al., 2021a;Knezevic et al., 2021a;Knezevic et al.,
2021b). Activation of the collateral pathway following occlusion
injury fully reduces occlusion syndrome (Vukojevic et al., 2018;
Gojkovic et al., 2020;Kolovrat et al., 2020;Gojkovic et al., 2021a;
Knezevic et al., 2021a;Knezevic et al., 2021a;Knezevic et al.,
2021b). Together, this evidence strongly supports a comparable
beneficial effect (i.e., a “bypassing key”) in rats with intra-
abdominal hypertension and multiple vessel compression. As a
follow-up, fully reduced abdominal compartment syndrome
appeared as a confirmative conceptual result.
To reverse abdominal compartment syndrome as a multiple
occlusion syndrome disaster, we improved the function of the
venous system with the stable gastric pentadecapeptide BPC 157.
Considering the multitude of vessels that had been directly
compressed, this improvement should be greater than that in
specific vessel occlusion syndromes (Vukojevic et al., 2018;
Gojkovic et al., 2020;Kolovrat et al., 2020;Gojkovic et al.,
2021a;Knezevic et al., 2021a;Knezevic et al., 2021a;Knezevic
et al., 2021b) or with an intragastric application of absolute
alcohol and intraperitoneal application of lithium overdose,
which induce an “occlusion-like”syndrome (Gojkovic et al.,
2021b;Strbe et al., 2021). This abdominal compartment
syndrome therapy addresses more than one known initial
target, i.e., single vessel occlusion (ligation) (Vukojevic et al.,
2018;Gojkovic et al., 2020;Kolovrat et al., 2020;Gojkovic et al.,
2021a;Knezevic et al., 2021a;Knezevic et al., 2021a;Knezevic
et al., 2021b) vs. intragastric application of absolute alcohol
(Gojkovic et al., 2021b) and intraperitoneal application of
lithium overdose (Strbe et al., 2021) vs. all vessels compressed
(increased intra-abdominal hypertension). Thus, by resolving
and compensating for damaged functions, the reversal of the
chain of harmful consequences of high intra-abdominal pressure
can be achieved and abdominal compartment syndrome recovery
FIGURE 9 | Illustrative presentation of gross and microscopic
presentation. Gross presentation. Stomach (a, A) and liver (b,B) (white letters)
after the increased intraabdominal pressure and medication (sc) (saline
(5 ml/kg, left, stomach and duodenum with multiple small hemorrhagic
lesions (a), and congested liver (b) presentation) or BPC 157 (10 ng/kg, right,
stomach and duodenum, and liver A, B): 25 mmHg (30 min) (a, A), and
40 mmHg (30 min) (b, B). The camera attached to a VMS-004 Discovery
Deluxe USB microscope (Veho, United States). Microscopy presentation.
Stomach (a, A) and colon (b, B) (black letters) presentation in rats with the
increased intra-abdominal pressure at 50 mmHg for 25 min treated at 10 min
increased intra-abdominal pressure time with saline (control, a, b) or BPC 157
(A, B). The control group showed marked hyperemia and congestion of the
stomach wall (a) and a reduction of the colonic crypts with focal denudation of
the superficial epithelia (b). BPC 157-treated rats exhibit presentation close to
normal gastrointestinal tract presentation (A, B). (HE; a, A, magnification ×100,
scale bar 200 μm; b, B, magnification ×200, scale bar 100 μm).
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Tepes et al. BPC 157 and Abdominal Compartment Syndrome
can occur. Thus, the beneficial findings in rats with severely
increased intra-abdominal pressure given the stable gastric
pentadecapeptide BPC 157 (for review, see Sikiric et al., 2018)
likely occurred due to the effect on compressed essential vessel
tributaries, both arterial and venous, peripherally and centrally.
As a likely rescue pathway, as seen in the rat Budd–Chiari
syndrome (Gojkovic et al., 2020), superior sagittal sinus
occlusion syndrome (Gojkovic et al., 2021a), and intragastric
application of absolute alcohol (Gojkovic et al., 2021b)or
intraperitoneal application of lithium overdose (Strbe et al.,
2021), we identified the activated azygos vein pathway and the
inferior vena cava–azygos vein–left superior vena cava pathway.
The azygos vein pathway was fully activated in BPC 157-treated
rats (and thereby provided additional direct blood flow delivery),
while it was collapsed in control saline-treated rats with intra-
abdominal hypertension.
There may be, however, other activated bypassing loops
(Vukojevic et al., 2018;Gojkovic et al., 2020;Kolovrat et al.,
2020;Gojkovic et al., 2021a;Knezevic et al., 2021a;Knezevic et al.,
2021a;Gojkovic et al., 2021b;Knezevic et al., 2021b). With the
harmful effects of intra-abdominal hypertension, peripherally but
also centrally, rats with an occluded superior sagittal sinus may be
an illustrative example (Gojkovic et al., 2021a). Therefore, we
identified central shunts through the ophthalmic vein, angularis
vein, facial anterior and posterior veins, and facial vein, as well as
the superior cerebral veins, the superior and inferior sinus
cavernosus, the sinus petrosus, the sinus transversus, the
external jugular vein, the subclavian vein, and the superior
vena cava (Gojkovic et al., 2021a). Moreover, with BPC 157
therapy delivered topically to the swollen brain, intraperitoneally
or intragastrically, a rapid attenuation of brain swelling was
observed (Gojkovic et al., 2021a). A similar syndrome also
FIGURE 10 | Lung (a, A, b, B) and liver (c, C, d, D) presentation in rats with the increased intra-abdominal pressure at 25 mmHg for 60 min (a, A, c, C)orat
50 mmHg for 25 min (b, B, d, D), treated at 10 min increased intra-abdominal pressure time with saline (control, a, b, c, d) or BPC 157 (A, B, C, D ). a, b. Lung parenchyma
with marked congestion and large areas of intra-alveolar hemorrhage in control rats. A, B. Normal lung parenchyma in BPC 157-treated rats. c, d. Vascular dilatation of
liver parenchyma in controls, normal architecture in BPC 157 treated rats (C) and slight congestion of liver parenchyma (D). (HE; magnification ×200, scale bar
100 μm(a, A, b, B);magnification ×100, scale bar 500 μm(c, C, d, D)).
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Tepes et al. BPC 157 and Abdominal Compartment Syndrome
appeared with peripherally induced syndromes, i.e., an occluded
superior mesenteric artery (Knezevic et al., 2021a) or vein
(Knezevic et al., 2021b), or both artery and vein (Knezevic
et al., 2021a). Commonly, as in the present study, BPC 157
therapy rapidly eliminated the increased pressure in the
superior sagittal sinus, severe portal and vena caval
hypertension, and aortal hypotension and moreover quickly
recruited collateral vessels, which abrogated venous and
arterial thrombosis (Gojkovic et al., 2021a;Knezevic et al.,
2021a;Knezevic et al., 2021a;Gojkovic et al., 2021b;Knezevic
et al., 2021b;Strbe et al., 2021). This was interpreted as a
widespread resolution of the Virchow triad (endothelium
injury, hypercoagulability, and stasis), which allowed recovery
from organ lesions (Vukojevic et al., 2018;Gojkovic et al., 2020;
FIGURE 11 | Heart (a, A, b, B, c, C) and kidney (d, D, e, E) presentation in the rats with the increased intra-abdominal pressure at 25 mmHg for 60 min (a, A, b, B, d,
D) or at 50 mmHg for 25 min (c, C, e, E), treated at 10 min increased intra-abdominal pressure time with saline (control, a, b, c, d, e) or BPC 157 (A, B, C, D, E). Marked
congestion of myocardium of control rats, with subendocardial infract found in all control rats at 25 mmHg (a, b), and at 50 mmHg of intra-abdominal pressure (c), while
myocardium was preserved in all BPC 157- treated rats (A, B, C). Severe congestion of renal tissue was found in control rats at 25 mmHg (d) and at 50 mmHg of
intra-abdominal pressure (e), while in BPC 157- treated rats, no changes were found at 25 mmHg intra-abdominal pressure (D) and only discrete congestion was found
at 50 mmHg of intra-abdominal pressure (E). (HE; magnification ×200, scale bar 100 μm(a, A); x400, scale bar 50 μm(b, B, c, C); x100, scale bar 500 μm(d, D, e, E)).
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Tepes et al. BPC 157 and Abdominal Compartment Syndrome
Kolovrat et al., 2020;Gojkovic et al., 2021a;Knezevic et al., 2021a;
Knezevic et al., 2021a;Gojkovic et al., 2021b;Knezevic et al.,
2021b;Strbe et al., 2021). Evidently, in the resolution of damage
due to increased intra-abdominal hypertension, peripherally
(Vukojevic et al., 2018;Gojkovic et al., 2020;Kolovrat et al.,
2020;Knezevic et al., 2021a;Knezevic et al., 2021a;Knezevic et al.,
2021b), centrally (Gojkovic et al., 2021a), or both peripherally and
centrally (Gojkovic et al., 2021b;Strbe et al., 2021), there is a
common therapeutic point from which BPC 157 operates.
Moreover, as BPC 157 therapy also works in advance, the
properly reactivated azygos vein pathway and improved
functioning of the combined inferior caval vein and left
superior caval vein may resist even higher intra-abdominal
hypertension (25 mmHg˂30 mmHg˂40 mmHg˂50 mmHg) and
prolonged intra-abdominal pressures increases (25–120 min).
There were no lethal outcomes despite the permanent
maintenance of high intra-abdominal pressures (note that
abdominal compartment syndrome with a sustained level of
25 mmHg may be fatal within 1 h (Strang et al., 2020)). As an
accurate conceptual analogy with the similar therapeutic effect in
occlusion syndromes (Vukojevic et al., 2018;Gojkovic et al., 2020;
Kolovrat et al., 2020;Gojkovic et al., 2021a;Knezevic et al., 2021a;
Knezevic et al., 2021a;Knezevic et al., 2021b) or alcohol and
lithium intoxication (Gojkovic et al., 2021b;Strbe et al., 2021),
BPC 157 therapy is effective against severe bradycardia and ST-
elevation until asystole, myocardial congestion, and infarction
before death. This beneficial effect meant that, with more severe
intra-abdominal hypertension, BPC 157 rats still exhibited
normal microscopic presentation of the heart. Thus, as before
(Vukojevic et al., 2018;Gojkovic et al., 2020;Kolovrat et al., 2020;
FIGURE 12 | Neuropathologic scoring (0–8), cerebral cortex, cerebellar cortex, hypothalamus, hippocampus, and the number of karyopyknotic cells, cerebral
cortex, cerebellar cortex, hypothalamus, hippocampus, in the thiopental-anesthetized rats with the increased intra-abdominal pressures at 50 mmHg for 25 min, at
30 mmHg or 40 mmHg for 30 min, at 25 mmHg for 60 min increased intra-abdominal pressures-time, and in the esketamine-anesthetized rats with the increased intra-
abdominal pressures at the 25 mmHg at the 120 min increased intra-abdominal pressures-time, following medication (BPC 157 10 μg/kg (light gray bars),
10 ng/kg (dark gray bars); saline 5 ml/kg (white bars)) given subcutaneously at 10 min increased intra-abdominal pressures-time. Minimum (min), maximum (max),
median (med), means ±SD, *P˂0.05, vs. control.
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Tepes et al. BPC 157 and Abdominal Compartment Syndrome
Gojkovic et al., 2021a;Knezevic et al., 2021a;Knezevic et al.,
2021a;Gojkovic et al., 2021b;Knezevic et al., 2021b;Strbe et al.,
2021), this activated alternative blood flow was provided
continuously maintained heart function, leading to near-
normal lung, liver, and kidney presentation, unlike the
extreme congestion and hemorrhage observed in control rats.
Collectively, these findings implicate that the heart, lungs, liver,
and kidney are BPC 157 therapeutic targets.
Thus, despite increased intra-abdominal pressure, BPC 157
therapy normalized portal and caval pressure and aortal pressure,
as well as portal vein and inferior caval vein and aorta
presentation. This maintenance may be essentially important.
Otherwise, high portal and caval hypertension, aortal
hypotension, exaggerated congestion of both the inferior caval
and superior mesenteric veins, and a narrowed aorta all appear
along with the most severe organ lesions. This clear damage has
also been seen in other vessel occlusion studies (Vukojevic et al.,
2018;Gojkovic et al., 2020;Kolovrat et al., 2020;Gojkovic et al.,
2021a;Knezevic et al., 2021a;Knezevic et al., 2021a;Gojkovic
et al., 2021b;Knezevic et al., 2021b;Strbe et al., 2021).
Conceptually, the gastrointestinal, liver, and kidney lesions
described here are illustrative cause-consequence relationships
indicative of an uninterrupted injurious course. Vice versa, when
the lesions are absent/abrogated, they clearly illustrate the
therapeutic effect of BPC 157 and an interrupted injurious course.
Thus, specific conceptual support in rats with high intra-
abdominal pressures is provided by gastrointestinal tract
failure, hemorrhagic lesions in the stomach, transmural
hyperemia of the entire gastrointestinal tract, stomach,
duodenum, and small and large bowel wall. The reduction of
FIGURE 13 | Neuropathological changes of the cerebral cortex (a, A, b, B), cerebellar cortex (c, C) and pons (d, D) in rats with the increased intra-abdominal
pressure at 25 mmHg for 60 min (a, A, c, C) or at 50 mmHg for 25 min (b, B, d, D), treated at 10 min increased intraabdominal pressure time with saline (control, a, b, c, d)
or BPC 157 (A, B, C, D). Generalized edema and congestion (a, b, c, d) with an increased number of karyopyknotic cells were found in the cerebral cortex (a, b) that was
significantly different from the cortex area in BPC 157-treated rats (A, B). In control rats, intracerebral hemorrhage was found in infratentorial space (d), mostly in
cerebellopontine angle/area (c) with generalized edema and congestion of central nervous system, while no hemorrhage (C) and only mild edema was found in treated
animals, mostly at 50 mmHg intra-abdominal pressure (D). (HE; magnification ×200, scale bar 100 μm(a, A, b, B, d, D);magnification ×100, scale bar 200 μm(c, C)).
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Tepes et al. BPC 157 and Abdominal Compartment Syndrome
villi in the intestinal mucosa and crypt reduction with focal
denudation of superficial epithelia and dilatation of the large
bowel illustrate vascular failure (Chan et al., 2014). Accordingly,
the liver and the kidney exhibited huge vascular congestion. Vice
versa, the normalized portal and caval pressure and aortal
pressure as a cause-consequence are convincing evidence of
the functioning “bypassing key”(i.e., the azygos vein).
Consequently, BPC 157-treated rats exhibited no or minimal
congestion in the gastrointestinal mucosa, with well-preserved
intestinal villi and colonic crypts and no dilatation of the large
bowel, as well as a maintained vascular supply and reduced
vascular failure (Chan et al., 2014). In the liver and kidney,
only mild congestion was observed at the highest intra-
abdominal pressures.
Furthermore, high intra-abdominal pressures/increased
intracranial pressures led to the severe presentation of brain
lesions. Equally, with therapy, the reversed injury course
(increased intra-abdominal pressure/reduced intracranial
FIGURE 14 | Bielschowsky and Klüver–Barrera histochemical staining presenting neuropathological changes of cerebral cortex in rats with the increased intra-
abdominal pressure at 30 mmHg for 30 min (a, A, b, B) treated at 10 min increased intraabdominal pressure time with saline (control a, b) or BPC 157 (A, B). In control
rats, an increased number of karyopyknotic cells was found in the cerebral cortex (white arrows) (A, B) that was significantly different from the cortex area in BPC 157-
treated rats (a, b). (Bielschowsky staining (a, A); Klüver–Barrera staining (b, B); magnification ×600, scale bar 50 μm). Neuropathological changes of hypothalamic/
thalamic area (c, C, d, D) presentation in rats with theincreased intra-abdominalpressure at25 mmHg for60 min (c, C) or at 50 mmHg for 25 min (d, D), treated at 10 min
increased intra-abdominal pressure time with saline (control, c, d) or BP C 157 (C, D). A marked karyopyknosis was found in all control rats (marked in oval) (c, 25 mmHg/
60 min); d, 50 mmHg/25 min) while preserved brain tissue was found in BPC 157-treated rats (C, 25 mmHg/60 min); D, 50 mmHg/25 min). (HE; magnification ×400,
scale bar 50 μm).
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Tepes et al. BPC 157 and Abdominal Compartment Syndrome
hypertension) led to reduced intracranial hypertension as the
ultimate therapeutic outcome when the venous system was
supported (i.e., activation of the azygos shunt). This was key
in the brain as well, as pressures were not rapidly transmitted up
through the venous system, and thereby brain presentation was
preserved. The brain was preserved both grossly (absent brain
swelling) and microscopically (consistent beneficial effect in all
brain areas). Evidently, the beneficial effect of BPC 157 acted
against the full range of brain lesions, in the order cerebellum
cortex >hypothalamus/thalamus >cerebral cortex. The cerebellar
cortex appeared to be the most affected, and the cerebral cortex
was the least affected. The hippocampus, with increased lesion
severity at higher intra-abdominal pressures, may be seen as a
particular target. On the other hand, the vicious course induced
by high intra-abdominal pressure can be simultaneously
initiated and perpetuated from different sites (it should be
noted that intracranial hypertension may essentially cause
pulmonary edema and impair pulmonary circulation (Chen,
2009)).
Both BPC 157 regimens (µg and ng) had a similar therapeutic
effect in all of the investigated protocols of abdominal
compartment syndrome. Further cause-consequence evidence
could be seen in BPC 157-treated rats with high intra-
abdominal pressures, as treatment largely abrogated both
arterial and venous thrombosis. This was seen before with
vessel occlusion (Vukojevic et al., 2018;Gojkovic et al., 2020;
Kolovrat et al., 2020;Gojkovic et al., 2021a;Knezevic et al., 2021a;
Knezevic et al., 2021a;Knezevic et al., 2021b), alcohol and lithium
intoxication (Gojkovic et al., 2021b;Strbe et al., 2021), and
abdominal aorta anastomosis (Hrelec et al., 2009). The effect
FIGURE 15 | Neuropathological changes of cerebellar cortex (a, A,b, B) and hippocampus (c,C,d,D) in rats with the increased intra-abdominal pressure at
25 mmHg for 60 min (a, A, c, C) or at 50 mmHg for 25 min (b, B, d, D), treated at 10 min increased intra-abdominal pressure time with saline (control, a, b, c, d) or BPC
157 (A, B, C, D). Control rats exhibited within cerebellar area karyopyknosis and degeneration of Purkinje cells (a, b). Marked and progressive karyopyknosis and
degeneration of pyramidal cell of the hippocampus was observed in control rats (arrows) at 25 mmHg intraabdominal pressure (c) and even more at 50 mmHg
intra-abdominal pressure (d). No change was found in the cerebellar and hippocampal area in BPC 157- treated rats at 25 mmHg intra-abdominal pressure (A, B, C) and
only rare hippocampal karyopyknotic cells (arrows) at 50 mmHg intra-abdominal pressure (D) (HE; magnification ×400, scale bar 50 μm).
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Tepes et al. BPC 157 and Abdominal Compartment Syndrome
occurred peripherally (i.e., the largest thrombosis initially
(i.e., 25 mmHg) appeared just in the hepatic veins, resembling
the presentation of Budd–Chiari syndrome (Gojkovic et al.,
2020)), and centrally (superior sagittal sinus). Abrogated
thrombosis, both peripherally and centrally (Vukojevic et al.,
2018;Gojkovic et al., 2020;Kolovrat et al., 2020;Gojkovic et al.,
2021a;Knezevic et al., 2021a;Knezevic et al., 2021a;Gojkovic
et al., 2021b;Knezevic et al., 2021b), means that stasis was
evidently avoided, or at least markedly reduced. Along with
the “bypassing key”and rapidly activated collaterals, Virchow’s
triad was consistently reduced, both peripherally and centrally
(Vukojevic et al., 2018;Gojkovic et al., 2020;Kolovrat et al., 2020;
Gojkovic et al., 2021a;Knezevic et al., 2021a;Knezevic et al.,
2021a;Gojkovic et al., 2021b;Knezevic et al., 2021b;Strbe et al.,
2021). In particular, BPC 157-induced endothelial maintenance
(Sikiric et al., 1994) and the “bypassing key”(Vukojevic et al.,
2018;Gojkovic et al., 2020;Kolovrat et al., 2020;Gojkovic et al.,
2021a;Knezevic et al., 2021a;Knezevic et al., 2021a;Gojkovic
et al., 2021b;Knezevic et al., 2021b;Strbe et al., 2021) occur along
with the previously noted BPC 157-NO system interactions. This
can involve the release of NO on its own (Sikiric et al., 1997;
Turkovic et al., 2004), as well as maintained NO system function
against NOS blockade (L-NAME) or overfunction (L-arginine)
(for review, see Sikiric et al., 2014). Furthermore, blood pressure
maintenance (Sikiric et al., 1997), maintained thrombocyte
function (S