Stable Gastric Pentadecapeptide BPC 157 Therapy: Effect on Reperfusion Following Maintained Intra-Abdominal Hypertension (Grade III and IV) in Rats

Given in reperfusion, the use of stable gastric pentadecapeptide BPC 157 is an effective therapy in rats. It strongly counteracted, as a whole, decompression/reperfusion-induced occlusion/occlusion-like syndrome following the worst circumstances of acute abdominal compartment and intra-abdominal hypertension, grade III and grade IV, as well as compression/ischemia-occlusion/occlusion-like syndrome. Before decompression (calvariectomy, laparotomy), rats had long-lasting severe intra-abdominal hypertension, grade III (25 mmHg/60 min) (i) and grade IV (30 mmHg/30 min; 40 mmHg/30 min) (ii/iii), and severe occlusion/occlusion-like syndrome. Further worsening was caused by reperfusion for 60 min (i) or 30 min (ii/iii). Severe vascular and multiorgan failure (brain, heart, liver, kidney, and gastrointestinal lesions), widespread thrombosis (peripherally and centrally) severe arrhythmias, intracranial (superior sagittal sinus) hypertension, portal and caval hypertension, and aortal hypotension were aggravated. Contrarily, BPC 157 therapy (10 µg/kg, 10 ng/kg sc) given at 3 min reperfusion times eliminated/attenuated venous hypertension (intracranial (superior sagittal sinus), portal, and caval) and aortal hypotension and counteracted the increases in organ lesions and malondialdehyde values (blood ˃ heart, lungs, liver, kidney ˃ brain, gastrointestinal tract). Vascular recovery promptly occurred (i.e., congested inferior caval and superior mesenteric veins reversed to the normal vessel presentation, the collapsed azygos vein reversed to a fully functioning state, the inferior caval vein–superior caval vein shunt was recovered, and direct blood delivery returned). BPC 157 therapy almost annihilated thrombosis and hemorrhage (i.e., intracerebral hemorrhage) as proof of the counteracted general stasis and Virchow triad circumstances and reorganized blood flow. In conclusion, decompression/reperfusion-induced occlusion/occlusion-like syndrome counteracted by BPC 157 therapy in rats is likely for translation in patients. It is noteworthy that by rapidly counteracting the reperfusion course, it also reverses previous ischemia-course lesions, thus inducing complete recovery.

This novel resolution of the reperfusion threat could provide a particular new therapy point, in particular, given the recent findings on mechanical compression-ischemia showing that rats could sustain severe intra-abdominal hypertension grade III and grade IV and resolve severe vascular and multiorgan failure and major occlusion/occlusion-like syndrome without major harm after receiving BPC 157 therapy [8].That, among others, included "bypassing key", as a particular cytoprotection endothelium recovery, activation of the azygos vein pathway, and direct blood flow delivery as a rapid rescue [8] (as in other occlusion/occlusion-like syndromes [9-25]), and these beneficial findings together could indicate a particular way to approach the issue of intra-abdominal hypertension in the resolving therapy.As a possible translation for critically ill patients, note that when not promptly recognized and treated, intra-abdominal hypertension leads to abdominal compartment syndrome, multiorgan dysfunction syndrome, and death [26][27][28][29].In addition, as stated, abdominal compartment syndrome is not a disease and, as such, it can have many causes and can develop within many disease processes [29], and thereby, as such, it may be at best approached using some of the general concepts, such as cytoprotection [30][31][32][33][34], which would offer particular solutions via cytoprotection agents' application.
Therefore, such therapy in the post-decompression time should resolve the worsening complexity of the advanced occlusion/occlusion-like syndrome.Antecedent to therapy, there is a syndrome that barely survives by itself (i.e., severe bradycardia and ST elevation until asystole) during ischemia and compression and the consequent disturbances, thrombosis, stasis, vascular and multiorgan failure, and lesions, as mentioned before [8].
As such [8], it has to be cured in reperfusion using the therapy even in the worst condition that would occur in reperfusion, arising simultaneously from many sides after the end of compression, anticipating the imminent aggravation.
Thus, a strong curative potential option in advanced injury courses should be to reestablish the significance of the therapy using cytoprotection agents that they have to have, as the concept has claimed [35] (while standard agents' effectiveness only before injury is limited in application [35]).Conceptually, this may be stable gastric pentadecapeptide BPC 157 (note: BPC 157 was used in an ulcerative colitis clinical trial, phase II, and in toxicology studies, a lethal dose (LD1) could be not achieved) [1][2][3][30][31][32][33][34].Conceptually for the stomach cytoprotection concept, native and stable in human gastric juice (i.e., more than 24 h), as a native cytoprotection mediator maintaining gastrointestinal tract integrity may translate into the particular therapy of other tissues and may be easily applied.In addition, in the cytoprotection concept [35], the cells afforded by the cytoprotection agent should equally resist noxious events, whether ischemia or reperfusion.Note that BPC 157, given in the reperfusion, showed a strong therapy effect in rats with the Pringle maneuver [10], stroke [17], spinal cord compression [37,38], and ischemic/reperfusion ulcerative colitis [39].There, in studies with one prime target [10,17,[37][38][39], there is the removal of the particular clamping (spinal cord) [37,38] and the reopening of the particular vessel(s) (i.e., Pringle maneuver, stroke, and ischemic/reperfusion ulcerative colitis) [10,17,39].Note that such therapy, when given in these circumstances, thereafter means resolved reperfusion consequences occurring from one major prime target while leaving the therapy effect to be demonstrated on reperfusion that is going on from a large number of sites that would generate reperfusion in post-decompression time in rats that have intra-abdominal hypertension.On the other hand, these procedures, taken together [10,17,[37][38][39], can indicate the functioning against reperfusion injuries from many sites as can be expected in post-decompression time in rats with previous severe intra-abdominal hypertension and compression.

Results
The post-decompression acute abdominal compartment period characterized reperfusion with the additional vascular failure, and the additional perilous syndrome occurred peripherally and centrally, providing a course that might be not spontaneously recovered.Before the reperfusion and subsequent medication, the rats that barely survived the considerable period of intra-abdominal hypertension grade III and grade IV, the vessel and organ compression, exhibited advanced vascular and multiorgan failure [8].There was full occlusion/occlusion-like syndrome, additionally presented with intracranial (superior sagittal sinus) hypertension, portal, and caval hypertension, aortal hypotension, progressed venous and arterial thrombosis peripherally and centrally, congested (i.e., inferior caval vein and superior mesenteric vein) and/or failed (i.e., azygos vein) major veins, and ECG disturbances.The brain damage appeared in all investigated areas.In the cerebral and cerebellar cortex, hypothalamus/thalamus, and hippocampus, it appeared as congestion, edema, and a larger area with an increased number of karyopyknotic cells and intracerebral hemorrhage, mostly in the infratentorial space, affecting the cerebello-angle/area.The rats presented myocardial congestion and subendocardial infarction; severe congestion; and hemorrhage in the lung, liver, and kidney.These were all attenuated/eliminated by BPC 157 therapy given during the compression period [8].In particular, in the gastrointestinal tract, they had considerable lesions, with an increase in severity from the upper to the lower part of the gastrointestinal tract.Likewise, the transmural hyperemia of the gastrointestinal tract, stomach, duodenum, and small and large bowel walls were counteracted, and there was a reduction in the number of villi in the intestinal mucosa and a reduction of the crypt, with the focal denudation of superficial epithelia, as well as a dilatation of the large bowel [8].
On the other hand, in the post-decompression acute abdominal compartment period, the circumstances alternating ischemia with reperfusion are much more demanding for the delayed therapy application during reperfusion.However, the results demonstrated the strong effects of the BPC 157 therapy given during reperfusion.Thus, by rapidly counteracting the reperfusion course, BPC 157 therapy could also reverse previous ischemia-course lesions, thereby inducing complete recovery.Thus, this therapy made this severe vascular and multiorgan failure and occlusion/occlusion-like syndrome, as a whole, fully reversible.
The sustained activation of the azygos vein occurred in all of the BPC 157-treated rats as the common key finding, and was responsible for the prompt effect of the stable gastric pentadecapeptide BPC 157 therapy application.Also, in the advanced reperfusion, the direct blood delivery from the inferior caval vein to the superior caval vein might occur to instantly break the injurious circle.The proof of the concept appeared as the counteraction of the adjacent adverse syndrome (i.e., attenuated/counteracted intracranial (superior sagittal sinus) hypertension and aortal hypotension; major ECG disturbances; progressing arterial and vein thrombosis; and lesions in the brain, heart, lungs, liver, kidneys, and gastrointestinal tract) and counteraction of the increased malondialdehyde (MDA) values in all of the affected organs.While initiated in the worse circumstances of the highly advanced injurious course, in the severely damaged rats, the BPC 157 therapy effect was comparable to the effects of the previous BPC 157 therapy of the mentioned occlusion/occlusion-like syndromes [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25].

Blood Pressure Disturbances
In previously intra-abdominal hypertensive rats, grade III and grade IV, after decompression and reperfusion initiation, if therapy was not given, the portal and caval hypertension, and even more the intracranial (superior sagittal sinus) hypertension as well as the aortal hypotension persisted and sustainably presented until the end of the experiments.The effectiveness of the therapy application appeared as a prompt reduction in the blood pressure disturbances (superior sagittal sinus, portal, and caval hypertension, and abdominal aorta hypotension) in rats that received BPC 157 therapy.A cause-consequence relation should indicate the beneficial effect occurring both peripherally (with portal and caval hypertension and aortal hypotension almost annihilated) as well as even more centrally (with superior sagittal sinus hypertension attenuated) (Table 1).Without BPC 157 therapy, even with the reperfusion, shared thrombosis (in veins and arteries) persisted peripherally, both in veins (i.e., portal vein and inferior caval vein) as well as in arteries (i.e., abdominal aorta) and centrally (i.e., superior sagittal sinus).Likewise, along with reperfusion, BPC 157 therapy might result in a prompt reduction in thrombosis, which appears both peripherally and centrally (Table 1).This might indicate the effective cause-consequence course of the therapy both peripherally and centrally.

Collateral Pathways, Blood Vessels, and Brain Gross Presentation
Indicatively, for a common clue that might continuously fail during compression and intra-abdominal hypertension and, thereby, also in the subsequent reperfusion after decompression, without therapy, all injured rats without therapy converge to considerable lesions.Thereby, in general (the completed post-intra-abdominal hypertension (grade III and grade IV) course) and in particular (considering each of the given reperfusion time points, (60 min, 30 min, and 30 min)), we might envisage the presentation of the consistently failed collateral pathways as a shared failure (Figures 1-3).Contrarily, with BPC 157 therapy, the advanced collateral pathway presentation is initiated immediately upon its delayed application.This might be seen in cause-consequence relation with the reversal of blood pressure disturbances, thrombosis fully counteracted in all vessels investigated, veins and arteries, providing that, peripherally and centrally, the particular vessels recruitment may compensate the major injured vessel failure to take reperfusion blood flow, and counteract blood stasis seeable with, peripherally and centrally.Evidently, relative volume changes (the congested vessels (superior mesenteric vein and inferior caval vein, since the trapped volume, congested liver and lung), dilated heart and collapsed vessels (not functioning azygos vein) and swollen brain) occurred as a part of the previous failure during intra-abdominal hypertension-induced compression and further worsening upon decompression-reperfusion (Table 2).Consequently, the increased relative volume of the superior mesenteric vein and inferior caval vein (congestion) BPC 157 might decrease.The failed volume of the azygos vein (as well as the abdominal aorta) was reversed (i.e., there was an increased relative volume as the azygos vein was reactivated).BPC 157 therapy might bring this vessel and heart presentation close to normal vessel and heart presentation and close to normal functioning to re-establish blood flow (with multiorgan lesion being largely attenuated) (almost annihilated portal and caval hypertension and aortal hypotension).Evidently, in the peripheral-central circuit, at the same time, there was brain swelling, increased intracranial (superior sagittal sinus) hypertension, and an increased volume (associated with considerable brain injuries) (see Section 2.3).BPC 157 administration rapidly counteracted these and induced a considerable decrease toward normal brain presentation and negative pressure values (Table 1).Illustrative presentation of blood vessels (a,B,c,D,e,F,g,H,i,J,k,L) in control rats (small italic letters) (a,c,e,g,i,k) and BPC 157-treated rats (capital italic letters) (B,D,F,H,J,L).Considerable failure or recovery was noted after decompression and reperfusion in rats who were subjected to the intraabdominal hypertension of 25 mmHg for 60 min (a,B,c,D) (i), 30 mmHg for 30 min (e,F,g,H) (ii), or 40 mmHg for 30 min (iii) (i,J,k,L) and sacrificed after the corresponding reperfusion period (60 min (i) (a,B,c,D) or 30 min (ii (e,F,g,H); iii (i,J,k,L))) depending on whether they had received (sc) saline (controls) or BPC 157 at 3 min reperfusion times.Commonly, controls presented the marked congestion of the superior mesenteric vein (dashed black arrows) and inferior caval vein (dashed violet arrows) and a collapsed azygos vein (dashed blue arrows) and aorta (dashed red arrows).Contrarily, BPC 157-treated rats exhibited a consistent therapy effect and counteracted failed vessel presentation; the superior mesenteric vein (full black arrows) and inferior caval vein (full violet arrows) reversed to normal vessel presentation; the collapsed azygos vein (full blue arrows) and aorta (full red arrows) fully recovered.Illustrative presentation of blood vessels (a,B,c,D,e,F,g,H,i,J,k,L) in control rats (small italic letters) (a,c,e,g,i,k) and BPC 157-treated rats (capital italic letters) (B,D,F,H,J,L).Considerable failure or recovery was noted after decompression and reperfusion in rats who were subjected to the intra-abdominal hypertension of 25 mmHg for 60 min (a,B,c,D) (i), 30 mmHg for 30 min (e,F,g,H) (ii), or 40 mmHg for 30 min (iii) (i,J,k,L) and sacrificed after the corresponding reperfusion period (60 min (i) (a,B,c,D) or 30 min (ii (e,F,g,H); iii (i,J,k,L))) depending on whether they had received (sc) saline (controls) or BPC 157 at 3 min reperfusion times.Commonly, controls presented the marked congestion of the superior mesenteric vein (dashed black arrows) and inferior caval vein (dashed violet arrows) and a collapsed azygos vein (dashed blue arrows) and aorta (dashed red arrows).Contrarily, BPC 157-treated rats exhibited a consistent therapy effect and counteracted failed vessel presentation; the superior mesenteric vein (full black arrows) and inferior caval vein (full violet arrows) reversed to normal vessel presentation; the collapsed azygos vein (full blue arrows) and aorta (full red arrows) fully recovered.

Heart and ECG Disturbances
We revealed, in the study of the ECG disturbances in the further reperfusion course following the prime acute abdominal compartment and the nodal rhythm, dominant ST elevation, bradycardia, a temporary rescue that occurred following decompression, and a sinus rhythm.Then, since 2 min reperfusion times, there were the nodal rhythm, significant ST elevation, shortened QTc interval, and bradycardia.Extreme bradycardia and asystole appeared as the ultimate outcomes at the end of the investigation period.In BPC 157-treated rats, these disturbances were largely absent during the whole reperfusion period (Table 3).This occurred along with normal heart microscopic presentation, unlike the severe myocardial congestion in controls.a,B,c,D,e,F,g,H,i,J,k,L), in control rats (small italic letters) (a,c,e,g,i,k) and BPC 157-treated rats (capital italic letters) (B,D,F,H,J,L).Considerable gross brain failure (swelling) or recovery (counteracted swelling) was noted after decompression and reperfusion in rats who were subjected to the intra-abdominal hypertension of 25 mmHg for 60 min (a,B,c,D) (i), 30 mmHg for 30 min (e,F,g,H) (ii), or 40 mmHg for 30 min (iii) (i,J,k,L) and sacrificed after the corresponding reperfusion period (60 min (i) (a,B,c,D) or 30 min (ii (e,F,g,H); iii (i,J,k,L))) depending on whether they had received (sc) saline (controls) or BPC 157 at 3 min reperfusion times.Commonly, controls presented marked brain swelling.Contrarily, BPC 157-treated rats exhibited a consistent therapy effect and counteracted brain swelling.

Heart and ECG Disturbances
We revealed, in the study of the ECG disturbances in the further reperfusion course following the prime acute abdominal compartment and the nodal rhythm, dominant ST elevation, bradycardia, a temporary rescue that occurred following decompression, and a sinus rhythm.Then, since 2 min reperfusion times, there were the nodal rhythm, significant ST elevation, shortened QTc interval, and bradycardia.Extreme bradycardia and asystole appeared as the ultimate outcomes at the end of the investigation period.In BPC 157treated rats, these disturbances were largely absent during the whole reperfusion period (Table 3).This occurred along with normal heart microscopic presentation, unlike the severe myocardial congestion in controls.Upon decompression, the increased MDA-value oxidative stress occurred in all investigated tissues given the MDA values (nmol/mg protein) in the brain (6.2 ± 0.2), heart (18 ± 5), lung (15 ± 5), liver (20 ± 6), kidney (10 ± 6), blood (17 ± 5), stomach (1.5 ± 0.3), small intestine (1.1 ± 0.3), and large intestine (0.9 ± 0.3) in the healthy rats.During reperfusion, the highest values occurred in the blood, heart, lung, and kidney, which likely received the greatest impact of the ongoing reperfusion.Lower values appeared in the brain.The lowest values occurred in the gastrointestinal tract.BPC 157 therapy counteracted both the MDA-value increase as well as the oxidative stress damages in all organs tested at the end of all decompression/reperfusion periods, which were investigated to provide additional proof for the concept (Table 4).Indicatively, for a failed common clue (i.e., intracranial (superior sagittal sinus), portal, and caval hypertension, and aortal hypotension; progressed thrombosis, peripherally and centrally; failed collateral recruitment; progressed thrombosis) after the regular course following intra-abdominal hypertension-induced compression, there is subsequent decompression and reperfusion confronted with already considerable organ lesions presenting particular post-syndrome (Table 5, Figures 4-8).
Table 5. Lesions, scored microscopically (heart, lung, liver, kidney, stomach, small and large intestine), or macroscopically (stomach), in rats at 60 min, 30 min, and 30 min following decompression after compression with intra-abdominal hypertension (25 mmHg/60 min; 30 mmHg/30 min; 40 mmHg/30 min).* p < 0.05, at least vs. control.Contrarily, the reduced severity of lesions due to BPC 157 therapy can be a part of the cause-consequence therapeutic course along with the reduced intracranial (superior sagittal sinus), portal, and caval hypertension, and aortal hypotension; attenuated/eliminated thrombosis; and immediate impact of the activated collateral pathway.

Heart
Given the marked congestion of the myocardium and subendocardial infarcts at the end of the compression period, the initial presentation before decompression and reperfusion might be complex.Thereby, it is interesting that at the end of the reperfusion period, all control rats exhibited pronounced congestion and the dilatation of coronary arteries and their intramyocardial branches; subendocardial infarction occurred in those, which had been subjected to grade IV intra-abdominal hypertension (Table 5, Figure 4).Likewise, as before during the compression period (BPC 157 given at 10 min intra-abdominal hypertension time, the equally high intra-abdominal pressures in BPC 157-treated rats led to preserved myocardium), in the reperfusion there is consistent BPC 157 therapy effect.There was only mild congestion in the myocardium and scattered subendocardial ischemic myocytes in rats who had been subjected to grade III intra-abdominal hypertension, and the same morphology was found in rats who had been subjected to grade IV intra-abdominal hypertension (Table 5, Figure 4).Note that this therapy effect occurred along with the counteracting effect on arrhythmias and thrombosis.C,D,e,f,G,H,i,j,K,L) in control rats (small italic letters) (a,b,e,f,i,j) and BPC 157-treated rats (capital italic letters) (C,D,G,H,K,L).Considerable lesions were noted after decompression and reperfusion in rats who were subjected to the intraabdominal hypertension of 25 mmHg for 60 min (a,b,C,D) (i), 30 mmHg for 30 min (e,f,G,H) (ii), or 40 mmHg for 30 min (iii) (i,j,K,L) and sacrificed after the corresponding reperfusion period (60 min (i) (a,b,C,D) or 30 min (ii (e,f,G,H); iii (i,j,K,L)) depending on whether they had received (sc) saline (controls) or BPC 157 at 3 min reperfusion times.Commonly, controls presented the marked congestion of the myocardium with pronounced congestion and the dilatation of coronary arteries and their intramyocardial branches (a,e,i), scattered subendocardial ischemic myocytes (b) (black arrows), and subendocardial infarction (f,j).Contrarily, BPC 157-treated rats exhibited a consistent therapy effect, only mild myocardium congestion (C,G,K), and scattered subendocardial ischemic myocytes (D,H,L) (black arrows).HE staining; magnification, 100×; scale bar, 200 µm (a,C,e,G,i,K) or magnification, 400×; scale bar, 100 µm (b,D,f,H,j,L).a,B,c,D,e,F) in control rats (small italic letters) (a,b,e,f,i,j) and BPC 157-treated rats (capital italic letters) (B,D,F).Considerable lesions were noted after decompression and reperfusion in rats who were subjected to the intra-abdominal hypertension of 25 mmHg for 60 min (a,B) (i), 30 mmHg for 30 min (c,D) (ii), or 40 mmHg for 30 min (iii) (e,F) and sacrificed after the corresponding reperfusion period (60 min (i) (a,B) or 30 min (ii (c,D); iii (e,F)) depending on whether they had received (sc) saline (controls) or BPC 157 at 3 min reperfusion times.Commonly, control animals exhibited the marked congestion of the lung parenchyma, thickening of the alveolar membranes due to capillary congestion, pulmonary edema, and dilatation of larger blood vessels (a,c,e).No changes appeared in the BPC 157-treated rats (B,D,F).HE staining; magnification, 100×; scale bar, 200 µm.

Liver
Without therapy, the initial presentation of a marked vascular dilation of the liver parenchyma at the end of the compression period (i.e., barely survived) appeared at the end of the reperfusion period as a pronounced dilatation of sinusoids and branches of the portal vein in portal tracts.Contrarily, BPC 157-treated rats presented with no changes or only mild congestion in the liver (Table 5, Figure 6).

Kidney
Without therapy, the initial presentation of renal congestion at the end of the compression period (i.e., barely survived) course at the end of the reperfusion period appeared as marked congestion of the renal parenchyma with moderate vascular congestion, and interstitial edema.Contrarily, either no changes or only mild congestion appeared in the BPC 157-treated rats (Table 5, Figure 7).

Gastrointestinal Lesion
Without therapy, the initial presentation of marked transmural hyperemia of the entire gastrointestinal tract, stomach, duodenum, and small and large bowel wall at the end of the compression period (i.e., barely survived) remained at the end of the reperfusion period as a marked transmural pronounced congestion and dilatation of the blood vessels (note: small hemorrhagic lesions occurred in the stomach).No changes were found in BPC 157-treated rats (Table 5, Figure 8).

Lung
Without therapy, the initial presentation of marked congestion in the lung at the end of the compression period (i.e., barely survived) appeared at the end of the reperfusion period as a marked congestion of the lung parenchyma, thickening of the alveolar membranes due to capillary congestion, pulmonary edema, and dilatation of larger blood vessels.Contrarily, no changes appeared in the BPC 157-treated rats (Table 5, Figure 5).

Liver
Without therapy, the initial presentation of a marked vascular dilation of the liver parenchyma at the end of the compression period (i.e., barely survived) appeared at the end of the reperfusion period as a pronounced dilatation of sinusoids and branches of the portal vein in portal tracts.Contrarily, BPC 157-treated rats presented with no changes or only mild congestion in the liver (Table 5, Figure 6).

Kidney
Without therapy, the initial presentation of renal congestion at the end of the compression period (i.e., barely survived) course at the end of the reperfusion period appeared as marked congestion of the renal parenchyma with moderate vascular congestion, and interstitial edema.Contrarily, either no changes or only mild congestion appeared in the BPC 157-treated rats (Table 5, Figure 7).

Gastrointestinal Lesion
Without therapy, the initial presentation of marked transmural hyperemia of the entire gastrointestinal tract, stomach, duodenum, and small and large bowel wall at the end of the compression period (i.e., barely survived) remained at the end of the reperfusion period as a marked transmural pronounced congestion and dilatation of the blood vessels (note: small hemorrhagic lesions occurred in the stomach).No changes were found in BPC 157-treated rats (Table 5, Figure 8).

A Perilous Syndrome Occurred Centrally 2.3.1. Brain Lesions, Cerebral and Cerebellar Cortex, Hypothalamus/Thalamus, and Hippocampus
The applied procedures included intra-abdominal hypertension grade III intra-abdominal hypertension (25 mmHg for 60 min) and grade IV intra-abdominal hypertension (30 mmHg and 40 mmHg both for 30 min) followed by decompression, and reperfusion for corresponding same periods before sacrifice.Thus, equal time-periods of ischemia and reperfusion were involved (60 min/60 min for grade III and 30 min/30 min for grade IV).Thus, the regular severe intra-abdominal hypertension-induced lesions were further affected with decompression and an equal time-period of reperfusion to produce the final considerable ischemia/reperfusion lesions and hemorrhage (i.e., intraventricular hemorrhage involving the third ventricle occurred at the end in rats with grade IV 40 mmHg intra-abdominal hypertension ischemia/reperfusion).In particular, these brain lesions appeared to be distinctively affected by high intra-abdominal pressure and reperfusion; in particular, with higher intra-abdominal hypertension, the cerebrum and hypothalamus were less affected, and the cerebellum and hippocampus were more affected (i.e., the most progressive hippocampal neuronal damage occurred with the highest intra-abdominal pressure).Thereby, after reperfusion, the lesion severity evidence of the major impact on the cerebrum and hypothalamus, and the weaker impact on the cerebellum and hippocampus, appeared as these brain lesions were distinctively affected by reperfusion following high intra-abdominal pressure.All brain lesions were attenuated/eliminated by BPC 157 therapy given in reperfusion (Table 6, Figures 9-12).

Hippocampus
Commonly, along with pronounced edema and congestion occurring in the brain tissue, control rats exhibited, in the hippocampus, moderate neurodegenerative changes, karyopyknosis, and the degeneration of pyramidal cells.Contrarily, BPC 157 rats exhibited only mild edema in the brain tissue and had no or only rare karyopyknotic cells in the hippocampus (Table 6, Figure 11).(a,B,c,D,e,F) in control rats (small italic letters) (a,c,e) and BPC 157-treated rats (capital italic letters) (B,D,F).Considerable lesions were noted after decompression and reperfusion in rats who were subjected to the intra-abdominal hypertension of 25 mmHg for 60 min (a,B) (i), 30 mmHg for 30 min (ii) (c,D), or 40 mmHg for 30 min (iii) (e,F) and sacrificed after the corresponding reperfusion period (60 min (i) (a,B), 30 min ((ii) (c,D) and (iii) (e,F))) depending on whether they had received (sc) saline (controls) or BPC 157 at 3 min reperfusion times.Commonly, in the brain tissue, pronounced edema and congestion  (a,B,c,D,e,F) in control rats (small italic letters) (a,c,e) and BPC 157-treated rats (capital italic letters) (B,D,F).Considerable lesions were noted after decompression and reperfusion in rats who were subjected to the intra-abdominal hypertension of 25 mmHg for 60 min (a,B) (i), 30 mmHg for 30 min (ii) (c,D), or 40 mmHg for 30 min (iii) (e,F) and sacrificed after the corresponding reperfusion period (60 min (i) (a,B), 30 min ((ii) (c,D) and (iii) (e,F))) depending on whether they had received (sc) saline (controls) or BPC 157 at 3 min reperfusion times.Commonly, in the brain tissue, pronounced edema and congestion occurred in controls.In the hippocampus, there were moderate neurodegenerative changes in the control animals.There were karyopyknosis and the degeneration of pyramidal cells of the hippocampus (black arrows).BPC 157 rats exhibited only mild edema in the brain tissue and no or only rare karyopyknotic cells in the hippocampus (black arrows).HE staining; magnification, 600×, scale bar, 50 µm.

Hypothalamus
Commonly, along with pronounced edema and congestion in the brain tissue, control rats presented, in the hippocampus, moderate neurodegenerative changes and karyopyknosis hypothalamic neurons.BPC 157 rats exhibited only mild edema in the brain tissue and no or only mild neurodegenerative changes in the hypothalamus (Table 6, Figure 12).(a,B,c,D,e,F) in control rats (small italic letters) (a,c,e) and BPC 157-treated rats (capital italic letters) (B,D,F).Considerable lesions were noted after decompression and reperfusion in rats who were subjected to the intraabdominal hypertension of 25 mmHg for 60 min (a,B) (i), 30 mmHg for 30 min (ii) (c,D), or 40 mmHg for 30 min (iii) (e,F) and sacrificed after the corresponding reperfusion period (60 min (i) (a,B), 30 min ((ii) (c,D) and (iii) (e,F))) depending on whether they had received (sc) saline (controls) or BPC 157 at 3 min reperfusion times.Commonly, in the brain tissue, pronounced edema and congestion occurred in controls.In the hippocampus, there were moderate to severe neurodegenerative changes in the control animals.There were karyopyknosis hypothalamic neurons (black arrows).BPC 157 rats exhibited only mild edema in the brain tissue and only rare karyopyknotic cells and mild neurodegenerative changes in the hypothalamus (black arrows).HE staining; magnification, 400×; scale bar, 100 µm.

Cerebrum
Regularly, all of the applied procedures-intra-abdominal hypertension of 25 mmHg for 60 min, 30 mmHg for 30 min, and 40 mmHg for 30 min, followed by decompression and reperfusion for corresponding periods before sacrifice-produced considerable lesions and hemorrhage.These results, however, considerably changed depending on the given medication, i.e., saline (controls) or BPC 157, at 3 min reperfusion times.Commonly, pronounced edema and congestion in the brain tissue were presented in controls.Contrarily, BPC 157-treated rats presented only mild edema in the brain tissue.A focal and deeper neocortical hemorrhage was found in control rats affecting the neocortex, the corpus callosum, the amygdala, and the striatum in the brain tissue.Contrarily, BPC 157 rats presented only smaller areas of neocortical hemorrhage.Likewise, controls exhibited moderate to severe neurodegenerative changes, which were presented in the cerebral cortex, and the karyopyknosis of cortical neurons, while BPC 157 rats exhibited consistently no or only mild neurodegenerative changes (Table 6, Figure 9).

Cerebellum
Commonly, controls presented pronounced edema and congestion in the brain tissue and moderate neurodegenerative changes in the cerebellar cortex.There were karyopyknosis and the degeneration of Purkinje cells of the cerebellar cortex.Contrarily, BPC 157 rats had only mild edema in the brain tissue and only mild neurodegenerative changes in the cerebellar cortex (Table 6, Figure 10).

Hippocampus
Commonly, along with pronounced edema and congestion occurring in the brain tissue, control rats exhibited, in the hippocampus, moderate neurodegenerative changes, karyopyknosis, and the degeneration of pyramidal cells.Contrarily, BPC 157 rats exhibited only mild edema in the brain tissue and had no or only rare karyopyknotic cells in the hippocampus (Table 6, Figure 11).

Hypothalamus
Commonly, along with pronounced edema and congestion in the brain tissue, control rats presented, in the hippocampus, moderate neurodegenerative changes and karyopyknosis hypothalamic neurons.BPC 157 rats exhibited only mild edema in the brain tissue and no or only mild neurodegenerative changes in the hypothalamus (Table 6, Figure 12).Thus, without given therapy, we evidenced pronounced edema and congestion in the brain tissue and focal and deeper neocortical hemorrhage in all control rats.All four regions-cerebral and cerebellar cortex, hypothalamus/thalamus, and hippocampus-had been affected by neurodegenerative changes.There were karyopyknosis and the degeneration of Purkinje cells of the cerebellar cortex and the karyopyknosis of cortical neurons and pyramidal cells of the hippocampus, as well as hypothalamic neurons.As mentioned before, these were present along with severe gross brain swelling, volume increase, and intracranial (superior sagittal sinus) hypertension.Contrarily, the BPC 157 therapy effect could be summarized as only mild edema and congestion in the brain tissue, with smaller areas of neocortical hemorrhage, visible only within superficial layers of the neocortex, as well as no or only rare karyopyknotic cells in all four regions.Severe gross brain swelling, volume increase, and intracranial (superior sagittal sinus) hypertension had been counteracted.
In summary, rats that had acute abdominal compartments, when undergoing decompression and reperfusion after BPC 157 therapy, exhibited no portal and caval hypertension, ameliorated aortal hypotension, markedly attenuated superior sagittal sinus hypertension, and no disturbed QTc interval.Additionally, venous and arterial thrombosis were almost annihilated, both peripherally and centrally; the lesions were counteracted, and the MDA value increases in the blood, brain, heart, lung, liver, kidney, and gastrointestinal tract were counteracted.Thus, BPC 157 therapy, given in either of the regimens (µg, ng), counteracted the adverse effects that would otherwise consistently appear along with post-acute abdom-inal compartment syndrome.The key finding regarding a particular activated collateral pathway, i.e., the azygos vein, which combined the inferior caval vein and left superior vein to reorganize blood flow, might be responsible for the noted beneficial effects.
Given the final beneficial result, it seems that as resolving by the BPC 157 therapy works during intra-abdominal hypertension [8], 25 mm Hg for 60 min, 30 mmHg for 30 min, and 40 mmHg for 30 min, it works even more given much later after decompression, during reperfusion and along with reperfusion.These can be two mutually supporting pieces (i.e., activation of the collateral pathways, azygos vein direct blood flow delivery, therapy given at 10 min compression-time, and established severe intra-abdominal hypertension [8]; activation of the collateral pathways, azygos vein direct blood flow delivery, therapy given after decompression, at 3 min reperfusion-time, and already advanced reperfusion) of the consistent vascular recovery evidence.This shows that BPC 157 therapy effectively resolves comparable periods of reperfusion (60 min after 60 min-intra-abdominal hypertension 25 mmHg; 30 min after 30 min-intra-abdominal hypertension 30 mm Hg; and 30 min after 30 min-intra-abdominal hypertension 40 mmHg).
Thus, along with the previous findings [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25], the provided evidence may verify that BPC 157 therapy can be effective when given throughout reperfusion after decompression in rats that have intra-abdominal hypertension and occlusion/occlusion-like syndrome for a considerable period, and that it can counteract the ongoing occlusion/occlusionlike syndrome as a whole and reperfusion-induced occlusion/occlusion-like syndrome in particular.Such a demonstration combines, in therapy terms, the opposite points: the reperfusion after the prime acute abdominal compartment, the dangerous course of occlusion/occlusion-like syndrome, and the post-decompression period and antecedent mechanical compression ischemia severe intra-abdominal hypertension grade III and grade IV occlusion/occlusion-like syndrome.This has occurred in a particular way, given that both were equally counteracted by the successful outcome of BPC 157 therapy.Moreover, to do this, this has revealed that BPC 157, through its rapid vascular effect along with reperfusion, simultaneously also resolved the antecedent ischemia/compression lesions and, thus, the previously mentioned ischemic occlusion/occlusion-like syndrome and further reperfusion occlusion/occlusion-like syndrome.
It is likely that BPC 157 therapy might provide a particular central/peripheral equation during reperfusion [30][31][32][33][34].There were, as proofs of the concept (the intracranial (superior sagittal sinus), portal, and caval hypertension, and aortal hypotension were counteracted) in either case, a rapid effect, reduced gross (i.e., brain swelling was rapidly counteracted) and microscopic organs lesions, congestion, and hemorrhage.Namely, BPC 157 therapy instantly recovered the heart (severe ECG disturbances and thrombosis were antagonized) as a whole, and also recovered the brain (along with brain swelling gross counteraction, microscopically, the lesions in all brain areas were antagonized).Thereby, simultaneously, an otherwise persisting harmful inability to drain venous blood adequately for a given cerebral blood inflow without raising venous pressures was counteracted, and on the other side, there were counteractions of congestion, hemorrhage, and lesions in the heart, lungs, liver, kidney, and gastrointestinal tract.As the prime or final result, the previously collapsed azygos vein was made fully functional (direct blood flow delivery, activated rescuing pathway), and the previously congested inferior caval and superior mesenteric veins were reversed, via BPC 157 therapy, to the normal vessel presentation.Together, the almost-eliminated thrombosis (peripherally and centrally) in arteries and veins can prove the eliminated general stasis, reorganized blood flow, and eliminated arrhythmias.Note that as before, in the counteraction of amphetamine arrhythmias [24], the shortened QT interval was counteracted.Regularly, this occurs with increased levels of catecholamine (likely to occur in reperfusion), potentially leading to sudden cardiac death [69][70][71][72][73][74].Further, along with annihilated thrombosis (peripherally and centrally), heart failure recovered as a whole [27,28], and this always appeared as a common effect.Thus, in addition to other occlusion/occlusion-like syndromes [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25], such effectiveness provides a network of therapy evidence in full reperfusion conditions, with heart, brain, and other organ lesions counteracted, thrombosis annihilated, and hemorrhage counteracted, with all these changes supporting each other.Consequently, Virchow triad circumstance reversal goes against one or more targets, each with a particular effect and a specificity depending on the injury, all orchestrated to achieve a "bypassing key" that might reverse the complete multiorgan failure syndrome and occlusion/occlusion-like syndrome, as a whole, in reperfusion conditions [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25].
Moreover, as perceived in all these findings in the original cytoprotective terms (i.e., endothelium protection → epithelium protection, through activated collateral pathways, i.e., azygos vein direct blood flow delivery), essential support could be mentioned for the interaction with the systems essentially involved in cytoprotection and vessel functioning, and for the NO-and-prostaglandins system as a whole [40][41][42][43][44][45]48,49].The BPC 157 beneficial action included inducing the NO release of its own [43,44] and the counteraction of the adverse effects of either NOS blockade or NOS over-stimulation [40][41][42][43][44][45]48,49]-in particular, the counteraction of L-NAME-hypertension [43] and the pro-thrombotic effect [45] and L-arginine-hypotension [43] and the anti-thrombotic effect [45].Likewise, there were counteractions of the large range of adverse effects of NSAIDs, both non-specific and specific; COX-1 and COX-2 inhibitors; and COX-2 inhibitors (i.e., ulceration, liver and brain injuries, and bleeding) [45][46][47][75][76][77][78][79].It is likely that these counteractions might also have occurred due to the particular effect on thrombocyte function maintenance without affecting coagulation pathways [45][46][47], particularly controlling vasomotor tone through the activation of the Src-Caveolin-1-eNOS pathway [48,49]).In addition, the counteraction of the increased malondialdehyde (MDA) values in all organs investigated, i.e., the blood, brain, heart, liver, kidney, and gastrointestinal tract, is the next piece of evidence that BPC 157 therapy exerts its pleiotropic beneficial effects in all rats that have intra-abdominal hypertension (grade III and grade IV), decompression, and reperfusion in a particular way.This might occur as part of the damaged vascular wall (note: the highest MDA values appeared in the blood) and in other cells of the tissues, especially in combination with the oxygen intermediates and defective endothelial production, as emphasized in acute abdominal compartment rescuing pitfalls [80] that would be hardly resolved.Thus, as we have suggested before [6,56,[60][61][62][63][64], it may be that BPC 157 therapy accordingly acts as a natural free scavenger, particularly in occlusion/occlusion-like syndrome [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25], counteracting, in reperfusion, the organ lesions as the oxidative stress damages and the consistent counteraction appear whatever the extent of the oxidative stress may be.Thereby, the heart, lung, liver, and kidney sustain major impacts and have high MDA values that affect these organ lesions and vice versa and, once counteracted, indicate the value of the therapy effect.Likewise, the lesions in the brain and gastrointestinal tract with the lower MDA values may be indicative of particular organ sensitivity (i.e., intracerebral hemorrhage), and, vice versa, of particular therapy effect value.As mentioned, these might constitute the BPC 157 selective action in decompression/reperfusion, related to its modulatory effects, at least, on two systems essentially involved in the cytoprotection concept and vascular integrity maintenance, prostaglandin system [40] and NO system [41][42][43][44][45]48,49], and its additional particular interaction with several molecular pathways [6,[48][49][50][51][52][53][54][55][56][57][58].Moreover, this may be a fully controlled response providing, for instance, in the counteraction of tumor-induced cachexia, the inhibition of catabolic pathways (IL-6, TNF-alpha) balanced with the stimulation of anabolic pathways (FoxO3a, p-AKT, p-mTOR, and P-GSK-3β) [6].This has been associated with its function as a stabilizer of cellular junction [56], leading to significantly mitigated leaky gut syndrome (by increasing tight junction protein ZO-1 expression) and transepithelial resistance [56].Likewise, there are inhibited the mRNA of inflammatory mediators (iNOS, IL-6, IFN, and TNF-alpha) while increased expression of HSP 70 and 90, and antioxidant proteins, such as HO-1, NQO-1, glutathione reductase, glutathione peroxidase 2, and GST-pi [56].Note that such counteraction via BPC 157 therapy may be important as blood-brain barrier injury, increased capillary permeability in the brain, increased extracellular fluid, cerebral white matter edema, and, finally, increased intracranial pressure during intra-abdominal hypertension have all been postulated to relate to the release of these cytokines [81][82][83].

Animals
This study was conducted with 12 week old, 200 g body weight, male albino Wistar rats, randomly assigned at 6 rats/group/interval.Rats were bred in-house at the Pharmacology Animal Facility, School of Medicine, Zagreb, Croatia.The animal facility was registered by the Directorate of Veterinary (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 40-70% and noise level 60 dB.Each cage was identified with dates, number of study, group, dose, and 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.Animal care was in compliance with standard operating procedures (SOPs) of the Pharmacology Animal 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 to the treatment.

Experimental Protocol
In deeply anesthetized rats (intraperitoneal (ip) injection of 40 mg/kg thiopental (Rotexmedica, Trittau, Germany) and 10 mg/kg diazepam (Apaurin; Krka, Novo Mesto, Slovenia)), we induced abdominal compartment syndrome with intraabdominal hypertension grade III and grade IV as described before [8].Intraperitoneal insufflation of ordinary air was controlled using a manual and digital manometer with a data lodger connected to a computer (DD890, Dostmann Electronic GmbH, Wertheim, Germany).Increased abdominal pressure was maintained (measurement interval of 1 s) at 25 mmHg for 60 min, at 30 mm for 30 min, and at 40 mm Hg for 30 min until the decompression (laparotomy and calvariectomy) and then followed by reperfusion for 60 min (25 mmHg), 30 min (30 mm Hg), or 30 min (40 mm Hg) until sacrifice.Rats received (/kg sc) BPC 157 (10 µg, 10 ng) or saline (5 mL) at 3 min reperfusion time.
Recording of the brain swelling was performed in rats before sacrifice.Briefly, for calvariectomy, 6 burr holes were drilled in three horizontal lines, all of them medially to the superior temporal lines and temporalis muscle attachments.The rostral two burr holes were placed just basally from the posterior interocular line, the basal two burr holes were placed just rostral to the lambdoid suture (and transverse sinuses) on both sides, and the middle two burr holes were placed in the line between the basal and rostral burr holes.
Laparatomized rats were checked for the corresponding presentation of the peripheral vessels (azygos vein, superior mesenteric vein, portal vein, inferior caval and abdominal aorta).Recording with a camera attached to a VMS-004 Discovery Deluxe USB microscope (Veho, Claymont, DE, USA) was performed until the end of the experiment and assessed at 60 min (25 mmHg), 30 min (30 mm Hg), or 25 min (40 mm Hg) reperfusion time.

Brain Volume, Heart Volume, and Vessel Volume Presentation
We applied the procedure used before in our previous vascular studies [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25].Brain volume, vessel volume, and heart volume were proportional to the changes in the brain, vessel, or heart surface areas.The presentation of the brain and peripheral vessels (superior mesenteric vein, inferior caval vein, azygos vein, and abdominal aorta) was recorded in deeply anaesthetized rats with a camera attached to a VMS-004 Discovery Deluxe USB microscope (Veho, Claymont, DE, USA) [14][15][16][17][18][19][20][21][26][27][28].The border of the brain (or vessels or heart) in each image was marked using ImageJ software, and then, the surface area of the brain (or veins or heart) was measured.This was done with brain (or vein or heart) images for healthy rats and then 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 ( A con A bpc ), where Acon was the arithmetic mean brain (or vein or heart) area of the control group and Abpc was the arithmetic mean brain (or vein or heart) area of the treated group.Starting from the square-cube law in Equations ( 1) and ( 2), an equation for the change in brain (or vein or heart) volume proportional to the change in brain (or vein or heart) surface area [6] was derived.In expressions (1-5), l is defined as any arbitrary one-dimensional length of the brain (for example, rostro-caudal length of the brain), used only for defining the one-dimensional proportion (l2/l1) between two observed brains (or veins or heart) and as an inter-factor (and because of that, it is not measured [6]) for deriving final expression (6).The procedure was as follows: A [3] (from [1], after dividing both sides by A1), l 2 l 1 = A 2 A 1 [4] (from [3], after taking the square root of both sides), (from [2], after dividing both sides by V1), and [6] (after incorporating expression (4) into Equation ( 5)).
We also assessed the neuronal pathological changes in acquired digital images saved as uncompressed 24-bit RGB TIFF files in the software program AnalySIS (Olympus Soft Imaging System GmbH, Munster, Germany), performing quantitative analysis of neuronal damage in the karyopyknotic areas.The neurons of cortical cerebral region, cerebellar region, hippocampus, and hypothalamus were counted in 10 different high-powered fields (HPF, 400×), and 3 to 5 serial sections of each sample were used to perform the counting as described in [84].The field size was 0.24 µm 2 .
We used four criteria for estimation of the edema: a pale myelin, sieve-like appearance of myelinated areas, dilation of perivascular and pericellular spaces, and vacuolar appearance of the neuropil of gray matter.Edema was graded as heavy, moderate, slight, or no edema (score 0-3) [84].
We estimated hemorrhage as percentage of affected brain area.Intraventricular hemorrhage was noted as present or absent.

Oxidative Stress
At the end of the experiment, oxidative stress in the collected tissue samples (brain, heart, lung, liver, kidney, stomach, small and large intestine, and blood) was assessed by quantifying the thiobarbituric acid-reactive species (TBARS) as malondialdehyde (MDA) [9,10,[12][13][14]19,20].The tissue samples were homogenized in PBS (pH 7.4) containing 0.1 mM butylated hydroxytoluene (BHT) (TissueRuptor, Qiagen, Valencia, CA, USA) and sonicated for 30 s in an ice bath (Ultrasonic Bath, Branson, MI, USA).Trichloroacetic acid (TCA, 10%) was added to the homogenate, the mixture was centrifuged at 3000 rpm for 5 min, and the supernatant was collected.Then, 1% TBA was added, and the samples were boiled (95 • C, 60 min).The tubes were then kept on ice for 10 min.Following centrifugation (14,000 rpm, 10 min), the absorbance of the mixture was determined at the wave length of 532 nm.The concentration of MDA was read from a standard calibration curve plotted using 1,1,3,3tetraethoxypropane (TEP).The extent of lipid peroxidation was expressed as MDA using a molar extinction coefficient for MDA of 1.56 × 10 5 mol/L/cm.The protein concentration was determined using a commercial kit.The results are expressed in nmol/mg of protein.

Statistical Analysis
Statistical analysis was performed using 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 U test to compare groups.Values are presented as means ± standard deviations (SDs) and as minimum/median/maximum values.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.

Figure 1 .
Figure 1.Illustrative presentation of blood vessels (a,B,c,D,e,F,g,H,i,J,k,L) in control rats (small italic letters) (a,c,e,g,i,k) and BPC 157-treated rats (capital italic letters) (B,D,F,H,J,L).Considerable failure or recovery was noted after decompression and reperfusion in rats who were subjected to the intraabdominal hypertension of 25 mmHg for 60 min (a,B,c,D) (i), 30 mmHg for 30 min (e,F,g,H) (ii), or 40 mmHg for 30 min (iii) (i,J,k,L) and sacrificed after the corresponding reperfusion period (60 min (i) (a,B,c,D) or 30 min (ii (e,F,g,H); iii (i,J,k,L))) depending on whether they had received (sc) saline (controls) or BPC 157 at 3 min reperfusion times.Commonly, controls presented the marked congestion of the superior mesenteric vein (dashed black arrows) and inferior caval vein (dashed violet arrows) and a collapsed azygos vein (dashed blue arrows) and aorta (dashed red arrows).Contrarily, BPC 157-treated rats exhibited a consistent therapy effect and counteracted failed vessel presentation; the superior mesenteric vein (full black arrows) and inferior caval vein (full violet arrows) reversed to normal vessel presentation; the collapsed azygos vein (full blue arrows) and aorta (full red arrows) fully recovered.

Figure 1 .
Figure 1.Illustrative presentation of blood vessels (a,B,c,D,e,F,g,H,i,J,k,L) in control rats (small italic letters) (a,c,e,g,i,k) and BPC 157-treated rats (capital italic letters) (B,D,F,H,J,L).Considerable failure or recovery was noted after decompression and reperfusion in rats who were subjected to the intra-abdominal hypertension of 25 mmHg for 60 min (a,B,c,D) (i), 30 mmHg for 30 min (e,F,g,H) (ii), or 40 mmHg for 30 min (iii) (i,J,k,L) and sacrificed after the corresponding reperfusion period (60 min (i) (a,B,c,D) or 30 min (ii (e,F,g,H); iii (i,J,k,L))) depending on whether they had received (sc) saline (controls) or BPC 157 at 3 min reperfusion times.Commonly, controls presented the marked congestion of the superior mesenteric vein (dashed black arrows) and inferior caval vein (dashed violet arrows) and a collapsed azygos vein (dashed blue arrows) and aorta (dashed red arrows).Contrarily, BPC 157-treated rats exhibited a consistent therapy effect and counteracted failed vessel presentation; the superior mesenteric vein (full black arrows) and inferior caval vein (full violet arrows) reversed to normal vessel presentation; the collapsed azygos vein (full blue arrows) and aorta (full red arrows) fully recovered.

Figure 2 .
Figure 2.Illustrative presentation of blood vessels and heart (a,B,c,D,e,F,g,H,i,J,k,L) in control rats (small italic letters) (a,c,e,g,i,k) and BPC 157-treated rats (capital italic letters) (B,D,F,H,J,L).Considerable failure or recovery was noted after decompression and reperfusion in rats who were subjected to the intra-abdominal hypertension of 25 mmHg for 60 min (a,B,c,D) (i), 30 mmHg for 30 min (e,F,g,H) (ii), or 40 mmHg for 30 min (iii) (i,J,k,L) and sacrificed after the corresponding reperfusion period (60 min (i) (a,B,c,D) or 30 min (ii (e,F,g,H); iii (i,J,k,L))) depending on whether they had received (sc) saline (controls) or BPC 157 at 3 min reperfusion times.Commonly, controls presented the marked congestion of the inferior caval vein (dashed violet arrows), a collapsed abdominal aorta (dashed red arrows), and a dilated heart.Contrarily, BPC 157-treated rats exhibited a consistent therapy effect and counteracted failed vessel and heart presentation; the inferior caval vein (full violet arrows) reversed to normal vessel presentation; the abdominal aorta (full red arrows) fully recovered and counteracted heart dilatation.

Figure 2 .
Figure 2.Illustrative presentation of blood vessels and heart (a,B,c,D,e,F,g,H,i,J,k,L) in control rats (small italic letters) (a,c,e,g,i,k) and BPC 157-treated rats (capital italic letters) (B,D,F,H,J,L).Considerable failure or recovery was noted after decompression and reperfusion in rats who were subjected to the intra-abdominal hypertension of 25 mmHg for 60 min (a,B,c,D) (i), 30 mmHg for 30 min (e,F,g,H) (ii), or 40 mmHg for 30 min (iii) (i,J,k,L) and sacrificed after the corresponding reperfusion period (60 min (i) (a,B,c,D) or 30 min (ii (e,F,g,H); iii (i,J,k,L))) depending on whether they had received (sc) saline (controls) or BPC 157 at 3 min reperfusion times.Commonly, controls presented the marked congestion of the inferior caval vein (dashed violet arrows), a collapsed abdominal aorta (dashed red arrows), and a dilated heart.Contrarily, BPC 157-treated rats exhibited a consistent therapy effect and counteracted failed vessel and heart presentation; the inferior caval vein (full violet arrows) reversed to normal vessel presentation; the abdominal aorta (full red arrows) fully recovered and counteracted heart dilatation.

Figure 3 .
Figure 3.Illustrative brain presentation, ex vivo and in vivo (a,B,c,D,e,F,g,H,i,J,k,L), in control rats (small italic letters) (a,c,e,g,i,k) and BPC 157-treated rats (capital italic letters) (B,D,F,H,J,L).Considerable gross brain failure (swelling) or recovery (counteracted swelling) was noted after decompression and reperfusion in rats who were subjected to the intra-abdominal hypertension of 25 mmHg for 60 min (a,B,c,D) (i), 30 mmHg for 30 min (e,F,g,H) (ii), or 40 mmHg for 30 min (iii) (i,J,k,L) and sacrificed after the corresponding reperfusion period (60 min (i) (a,B,c,D) or 30 min (ii (e,F,g,H); iii (i,J,k,L))) depending on whether they had received (sc) saline (controls) or BPC 157 at 3 min reperfusion times.Commonly, controls presented marked brain swelling.Contrarily, BPC 157-treated rats exhibited a consistent therapy effect and counteracted brain swelling.

Figure 3 .
Figure 3.Illustrative brain presentation, ex vivo and in vivo (a,B,c,D,e,F,g,H,i,J,k,L), in control rats (small italic letters) (a,c,e,g,i,k) and BPC 157-treated rats (capital italic letters) (B,D,F,H,J,L).Considerable gross brain failure (swelling) or recovery (counteracted swelling) was noted after decompression and reperfusion in rats who were subjected to the intra-abdominal hypertension of 25 mmHg for 60 min (a,B,c,D) (i), 30 mmHg for 30 min (e,F,g,H) (ii), or 40 mmHg for 30 min (iii) (i,J,k,L) and sacrificed after the corresponding reperfusion period (60 min (i) (a,B,c,D) or 30 min (ii (e,F,g,H); iii (i,J,k,L))) depending on whether they had received (sc) saline (controls) or BPC 157 at 3 min reperfusion times.Commonly, controls presented marked brain swelling.Contrarily, BPC 157-treated rats exhibited a consistent therapy effect and counteracted brain swelling.

Figure 5 .
Figure 5. Microscopic changes presented in the lung (a,B,c,D,e,F) in control rats (small italic letters) (a,b,e,f,i,j) and BPC 157-treated rats (capital italic letters) (B,D,F).Considerable lesions were noted after decompression and reperfusion in rats who were subjected to the intra-abdominal hypertension of 25 mmHg for 60 min (a,B) (i), 30 mmHg for 30 min (c,D) (ii), or 40 mmHg for 30 min (iii) (e,F) and sacrificed after the corresponding reperfusion period (60 min (i) (a,B) or 30 min (ii (c,D); iii (e,F)) depending on whether they had received (sc) saline (controls) or BPC 157 at 3 min reperfusion times.Commonly, control animals exhibited the marked congestion of the lung parenchyma, thickening of the alveolar membranes due to capillary congestion, pulmonary edema, and dilatation of larger blood vessels (a,c,e).No changes appeared in the BPC 157-treated rats (B,D,F).HE staining; magnification, 100×; scale bar, 200 µm.

Figure 5 .
Figure 5. Microscopic changes presented in the lung (a,B,c,D,e,F) in control rats (small italic letters) (a,b,e,f,i,j) and BPC 157-treated rats (capital italic letters) (B,D,F).Considerable lesions were noted after decompression and reperfusion in rats who were subjected to the intra-abdominal hypertension of 25 mmHg for 60 min (a,B) (i), 30 mmHg for 30 min (c,D) (ii), or 40 mmHg for 30 min (iii) (e,F) and sacrificed after the corresponding reperfusion period (60 min (i) (a,B) or 30 min (ii (c,D); iii (e,F)) depending on whether they had received (sc) saline (controls) or BPC 157 at 3 min reperfusion times.Commonly, control animals exhibited the marked congestion of the lung parenchyma, thickening of the alveolar membranes due to capillary congestion, pulmonary edema, and dilatation of larger blood vessels (a,c,e).No changes appeared in the BPC 157-treated rats (B,D,F).HE staining; magnification, 100×; scale bar, 200 µm.

Figure 6 .
Figure 6.Microscopic changes presented in the liver (a,B,c,D,e,F) in control rats (small italic letters) (a,b,e,f,i,j) and BPC 157-treated rats (capital italic letters) (B,D,F).Considerable lesions were noted after decompression and reperfusion in rats who were subjected to the intra-abdominal hypertension of 25 mmHg for 60 min (a,B) (i), 30 mmHg for 30 min (c,D) (ii), or 40 mmHg for 30 min (iii) (e,F) and sacrificed after the corresponding reperfusion period (60 min (i) (a,B) or 30 min (ii (c,D); iii (e,F)) upon receiving (sc) saline (controls) or BPC 157 at 3 min reperfusion times.Commonly, control animals exhibited the marked congestion of the liver parenchyma, with a pronounced dilatation of sinusoids and branches of the portal vein in portal tracts (a,c,e).No changes or mild congestion appeared in the BPC 157-treated rats (B,D,F).HE staining; magnification, 100×; scale bar, 200 µm.

Figure 6 .
Figure 6.Microscopic changes presented in the liver (a,B,c,D,e,F) in control rats (small italic letters) (a,b,e,f,i,j) and BPC 157-treated rats (capital italic letters) (B,D,F).Considerable lesions were noted after decompression and reperfusion in rats who were subjected to the intra-abdominal hypertension of 25 mmHg for 60 min (a,B) (i), 30 mmHg for 30 min (c,D) (ii), or 40 mmHg for 30 min (iii) (e,F) and sacrificed after the corresponding reperfusion period (60 min (i) (a,B) or 30 min (ii (c,D); iii (e,F)) upon receiving (sc) saline (controls) or BPC 157 at 3 min reperfusion times.Commonly, control animals exhibited the marked congestion of the liver parenchyma, with a pronounced dilatation of sinusoids and branches of the portal vein in portal tracts (a,c,e).No changes or mild congestion appeared in the BPC 157-treated rats (B,D,F).HE staining; magnification, 100×; scale bar, 200 µm.

Figure 7 .
Figure 7. Microscopic changes presented in the kidney (a,B,c,D,e,F) in control rats (small italic letters) (a,b,e,f,i,j) and BPC 157-treated rats (capital italic letters) (B,D,F).Considerable lesions were noted after decompression and reperfusion in rats who were subjected to the intra-abdominal hypertension of 25 mmHg for 60 min (a,B) (i), 30 mmHg for 30 min (c,D) (ii), or 40 mmHg for 30 min (iii) (e,F) and sacrificed after the corresponding reperfusion period (60 min (i) (a,B) or 30 min (ii (c,D); iii (e,F)) upon receiving (sc) saline (controls) or BPC 157 at 3 min reperfusion times.Commonly, control animals exhibited the marked congestion of the renal parenchyma with moderate

Figure 7 .
Figure 7. Microscopic changes presented in the kidney (a,B,c,D,e,F) in control rats (small italic letters) (a,b,e,f,i,j) and BPC 157-treated rats (capital italic letters) (B,D,F).Considerable lesions were noted after decompression and reperfusion in rats who were subjected to the intra-abdominal hypertension of 25 mmHg for 60 min (a,B) (i), 30 mmHg for 30 min (c,D) (ii), or 40 mmHg for 30 min (iii) (e,F) and sacrificed after the corresponding reperfusion period (60 min (i) (a,B) or 30 min (ii (c,D); iii (e,F)) upon receiving (sc) saline (controls) or BPC 157 at 3 min reperfusion times.Commonly, control animals exhibited the marked congestion of the renal parenchyma with moderate vascular congestion, and interstitial edema occurred in control rats (a,c,e).No changes or mild congestion appeared in the BPC 157-treated rats (B,D,F).HE staining; magnification, 100×; scale bar, 200 µm.

Figure 8 . 8 .
Figure 8. Microscopic changes presented in the stomach (a,B,c,D,e,F) in control rats (small italic letters) (a,b,e,f,i,j) and BPC 157-treated rats (capital italic letters) (B,D,F).Considerable lesions were Figure 8. Microscopic changes presented in the stomach (a,B,c,D,e,F) in control rats (small italic letters) (a,b,e,f,i,j) and BPC 157-treated rats (capital italic letters) (B,D,F).Considerable lesions were noted after decompression and reperfusion in rats who were subjected to the intra-abdominal hypertension of 25 mmHg for 60 min (a,B) (i), 30 mmHg for 30 min (c,D) (ii), or 40 mmHg for 30 min (iii) (e,F) and sacrificed after the corresponding reperfusion period (60 min (i) (a, B) or 30 min (ii (c,D); iii (e,F)) depending on whether they had received (sc) saline (controls) or BPC 157 at 3 min reperfusion times.Commonly, control animals exhibited the marked congestion of the stomach wall due to the transmural pronounced congestion and dilatation of the blood vessels (a,c,e).No changes appeared in the BPC 157-treated rats (B,D,F).HE staining; magnification, 100×; scale bar, 200 µm.

Figure 9 .
Figure 9. Neuropathological changes presented in the cerebrum (a,b,C,D,e,f,G,H) in control rats (small italic letters) (a,b,e,f) and BPC 157-treated rats (capital italic letters) (C,D,G,H).Considerable lesions were noted after decompression and reperfusion in rats who were subjected to the intraabdominal hypertension of 25 mmHg for 60 min (a,b,C,D) (i) or 40 mmHg for 30 min (ii) (e,f,G,H) and sacrificed after the corresponding reperfusion period (60 min (i) (a,b,C,D) or 30 min (ii)) (e,f,G,H) depending on whether they had received (sc) saline (controls) or BPC 157 at 3 min reperfusion times.Commonly, controls presented a pronounced edema and congestion in the brain tissue.In the BPC 157-treated rats (capital italic letters), only mild edema in the brain tissue was found.A focal and deeper neocortical hemorrhage was found in control animals affecting the neocortex, corpus callosum, amygdala, and striatum in the brain tissue (marked areas-(i): (a); (ii): (e)).In the BPC 157 group, only smaller areas of neocortical hemorrhage occurred (marked areas-(i): (C); (ii): (G)).Moderate to severe neurodegenerative changes were presented in the cerebral cortex, along with the karyopyknosis of cortical neurons, in controls (marked areas, black arrows) ((i): (b); (ii): (f)) while BPC 157 rats exhibited, consistently, only rare karyopyknotic cells and mild neurodegenerative changes ((i): (D); (ii): (H)).HE staining; magnification, 200×; scale bar, 200 µm.

Figure 10 .
Figure 10.Neuropathological changes presented in the cerebellum (a,B,c,D,e,F) in control rats (small italic letters) (a,c,e) and BPC 157-treated rats (capital italic letters) (B,D,F).Considerable lesions were noted after decompression and reperfusion in rats who were subjected to the intra-abdominal hypertension of 25 mmHg for 60 min (a,B) (i), 30 mmHg for 30 min (ii) (c,D), or 40 mmHg for 30 min (iii) (e,F) and sacrificed after the corresponding reperfusion period (60 min (i) (a,B) or 30 min ((ii) (c,D), and (iii) (e,F))) depending on whether they had received (sc) saline (controls) or BPC 157 at 3 min reperfusion times.Commonly, in the brain tissue, pronounced edema and congestion occurred in controls.Moderate neurodegenerative changes in the cerebellar cortex were found in control animals.There were karyopyknosis and the degeneration of Purkinje cells of the cerebellar cortex (black arrows).In BPC 157 rats, only mild edema in the brain tissue was found, and only rare karyopyknotic cells and mild neurodegenerative changes in the cerebellar cortex occurred (black arrows).HE staining; magnification, 400×; scale bar, 100 µm.

Figure 10 .
Figure 10.Neuropathological changes presented in the cerebellum (a,B,c,D,e,F) in control rats (small italic letters) (a,c,e) and BPC 157-treated rats (capital italic letters) (B,D,F).Considerable lesions were noted after decompression and reperfusion in rats who were subjected to the intraabdominal hypertension of 25 mmHg for 60 min (a,B) (i), 30 mmHg for 30 min (ii) (c,D), or 40 mmHg for 30 min (iii) (e,F) and sacrificed after the corresponding reperfusion period (60 min (i) (a,B) or 30 min ((ii) (c,D), and (iii) (e,F))) depending on whether they had received (sc) saline (controls) or BPC 157 at 3 min reperfusion times.Commonly, in the brain tissue, pronounced edema and congestion occurred in controls.Moderate neurodegenerative changes in the cerebellar cortex were found in control animals.There were karyopyknosis and the degeneration of Purkinje cells of the cerebellar cortex (black arrows).In BPC 157 rats, only mild edema in the brain tissue was found, and only rare karyopyknotic cells and mild neurodegenerative changes in the cerebellar cortex occurred (black arrows).HE staining; magnification, 400×; scale bar, 100 µm.

Figure 11 .
Figure 11.Neuropathological changes presented in the hippocampus (a,B,c,D,e,F) in control rats (small italic letters) (a,c,e) and BPC 157-treated rats (capital italic letters) (B,D,F).Considerable lesions were noted after decompression and reperfusion in rats who were subjected to the intra-abdominal hypertension of 25 mmHg for 60 min (a,B) (i), 30 mmHg for 30 min (ii) (c,D), or 40 mmHg for 30 min (iii) (e,F) and sacrificed after the corresponding reperfusion period (60 min (i) (a,B), 30 min ((ii) (c,D) and (iii) (e,F))) depending on whether they had received (sc) saline (controls) or BPC 157 at 3 min reperfusion times.Commonly, in the brain tissue, pronounced edema and congestion

Figure 11 .
Figure 11.Neuropathological changes presented in the hippocampus (a,B,c,D,e,F) in control rats (small italic letters) (a,c,e) and BPC 157-treated rats (capital italic letters) (B,D,F).Considerable lesions were noted after decompression and reperfusion in rats who were subjected to the intra-abdominal hypertension of 25 mmHg for 60 min (a,B) (i), 30 mmHg for 30 min (ii) (c,D), or 40 mmHg for 30 min (iii) (e,F) and sacrificed after the corresponding reperfusion period (60 min (i) (a,B), 30 min ((ii) (c,D) and (iii) (e,F))) depending on whether they had received (sc) saline (controls) or BPC 157 at 3 min reperfusion times.Commonly, in the brain tissue, pronounced edema and congestion occurred in controls.In the hippocampus, there were moderate neurodegenerative changes in the control animals.There were karyopyknosis and the degeneration of pyramidal cells of the hippocampus (black arrows).BPC 157 rats exhibited only mild edema in the brain tissue and no or only rare karyopyknotic cells in the hippocampus (black arrows).HE staining; magnification, 600×, scale bar, 50 µm.

Figure 12 .
Figure 12.Neuropathological changes presented in the hypothalamus (a,B,c,D,e,F) in control rats (small italic letters) (a,c,e) and BPC 157-treated rats (capital italic letters) (B,D,F).Considerable lesions were noted after decompression and reperfusion in rats who were subjected to the intraabdominal hypertension of 25 mmHg for 60 min (a,B) (i), 30 mmHg for 30 min (ii) (c,D), or 40 mmHg for 30 min (iii) (e,F) and sacrificed after the corresponding reperfusion period (60 min (i) (a,B), 30 min ((ii) (c,D) and (iii) (e,F))) depending on whether they had received (sc) saline (controls) or BPC 157 at 3 min reperfusion times.Commonly, in the brain tissue, pronounced edema and congestion occurred in controls.In the hippocampus, there were moderate to severe neurodegenerative changes in the control animals.There were karyopyknosis hypothalamic neurons (black arrows).BPC 157 rats exhibited only mild edema in the brain tissue and only rare karyopyknotic cells and mild neurodegenerative changes in the hypothalamus (black arrows).HE staining; magnification, 400×; scale bar, 100 µm.

Table 3 .
ECG changes in rats after acute abdominal compartment, course during reperfusion and after therapy application.* p < 0.05, at least vs. control.
ECG Changes

in Rats after Acute Abdominal Compartment, Course during Reperfusion and after Therapy Application
*ST elevation, mV, means