Induction Of Hemorrhagic Shock Research Articles

Abstract 200: A Newly Drug Delivery System Combined With the Resuscitative Endovascular Balloon Occlusion of the Aorta in a Pig With Hemorrhagic Shock Model

Background: The use of resuscitative endovascular balloon occlusion of the aorta (REBOA) for hemorrhagic shock (HS) has grown in popularity. However, REBOA has a risk of complications related to blocking the blood flow downstream to the visceral organs. Several drugs have been reported so far to mitigate ischemia, including hydrogen gas (H 2 ); however, they could not reach the downstream of REBOA as they are distributed through the bloodstream. This study aimed to develop a system to deliver drugs to the ischemic organs where REBOA blocks the bloodstream. Methods: Herein, a female 40-kg swine volume-regulated HS model was used. In addition to the REBOA in zone 1, a catheter was inserted for drug delivery retrograde into the right femoral artery. The top tip of the catheter was positioned distal to the REBOA balloon. After HS induction (20% of the total blood volume), drug delivery capability was evaluated in three REBOA use patterns, such as controlled HS in normal time of full inflation , uncontrolled HS with liver injury in extended time of full inflation, and partial inflation. Simultaneously with the REBOA inflation, the intra-aortic irrigation of a drug-containing solution, H 2 -dissolved saline, was initiated. Results: The occlusion by the REBOA was achieved in all cases after shock induction (approximately 40 mmHg). In all patterns, the concentration of H 2 in the portal vein, which represents the concentration of outflow from the intestine and inflow to the liver, increased immediately after the irrigation. A full inflation setting required 30 mL/min of irrigation speed to obtain the minimum effective concentration of H 2 (1%), whereas a partial inflation setting required 2 mL/min. Conclusion: A drug delivery system combined with the REBOA was developed, which enabled the drugs to be administered downstream of REBOA. The newly developed system can potentially overcome the major limitations of REBOA.

Abstract 375: Resuscitative Endovascular Balloon Occlusion of the Aorta With Downstream Intra-Aortic Irrigation Using Hydrogen-Containing Solution Mitigates Ischemic Injury in a Swine Hemorrhagic Shock With Liver Injury Model

Background: Recently, the resuscitative endovascular balloon occlusion of the aorta (REBOA) has become widespread in hemorrhagic shock (HS). It temporarily increases the proximal blood pressure (pBP); but sacrifices the distal blood flow to the visceral organs, causing ischemic injury. We previously reported that hydrogen (H 2 ) gas inhalation mitigated ischemic injury and improved survival in rats with HS; however, during REBOA use, the H 2 gas was not delivered to the ischemic organs as it is distributed via the bloodstream. Therefore, we hypothesized that intra-aortic irrigation of H 2 -containing solution into the downstream of REBOA would mitigate ischemic injury. Methods: Herein, a swine liver injury with volume-regulated HS model was used. The female swine (around 40 kg, n = 16) were divided into two groups; a H 2 -containing solution irrigation (H 2 group) and saline irrigation (C group). After HS induction (20% of estimated total blood volume), the liver injury was initiated (20% of total liver volume). The REBOA was inflated during predefined time (60 min and 90 min) and intra-aortic irrigation to downstream of REBOA was started. The hemodynamic parameters, blood samples, and pathological changes were evaluated. Results: The elevation in lactate, interleukin 6, and syndecan levels were significantly suppressed over time in the H 2 group than in C group (p < 0.05). The pBP tended to decrease during REBOA in the C group; however, it remained higher in H 2 group (p < 0.05). Pathologically, the ischemic changes, such as liver sinusoidal enlargement and intestinal villi flattening and inflammatory infiltration were identified in the C group but not in H 2 group. Conclusion: The REBOA with downstream intra-aortic irrigation using H 2 -containing solution for liver injury with HS stabilizes hemodynamics, suppresses cellular injury, and mitigates organ damages. These results in large animals can be immediately applied to clinical use in humans.

Liposome-Encapsulated Hemoglobin Vesicle Improves Persistent Anti-arrhythmogenesis through Improving Myocardial Electrical Remodeling and Modulating Cardiac Autonomic Activity in a Hemorrhagic Shock-Induced Rat Heart Model

Shock heart syndrome (SHS) is associated with lethal arrhythmias (ventricular tachycardia/ventricular fibrillation, VT/VF). We investigated whether liposome-encapsulated human hemoglobin vesicles (HbVs) has comparable persistent efficacy to washed red blood cells (wRBCs) for improving arrhythmogenesis in the subacute to chronic phase of SHS. Optical mapping analysis (OMP), electrophysiological study (EPS), and pathological examinations were performed on blood samples from Sprague-Dawley rats following induction of hemorrhagic shock. After hemorrhagic shock, the rats were immediately resuscitated by transfusing 5% albumin (ALB), HbV, or wRBCs. All rats survived for 1 week. OMP and EPS were performed on Langendorff-perfused hearts. Spontaneous arrhythmias and heart rate variability (HRV) were evaluated using awake 24-h telemetry, cardiac function by echocardiography, and pathological examination of Connexin43. OMP showed significantly impaired action potential duration dispersion (APDd) in the left ventricle (LV) in the ALB group whereas APDd was substantially preserved in the HbV and wRBCs groups. Sustained VT/VF was easily provoked by EPS in the ALB group. No VT/VF was induced in the HbV and wRBCs groups. HRV, spontaneous arrhythmias, and cardiac function were preserved in the HbV and wRBCs groups. Pathology showed myocardial cell damage and Connexin43 degradation in the ALB group, all of which were attenuated in the HbV and wRBCs groups. LV remodeling after hemorrhagic shock caused VT/VF in the presence of impaired APDd. Similar to wRBCs, HbV persistently prevented VT/VF by inhibiting persistent electrical remodeling, preserving myocardial structures, and ameliorating arrhythmogenic modifying factors in the subacute to chronic phase of hemorrhagic shock-induced SHS.

ER stress preconditioning ameliorates liver damage after hemorrhagic shock and reperfusion.

The mismatch of oxygen supply and demand during hemorrhagic shock disturbs endoplasmic reticulum (ER) homeostasis. The resulting accumulation of unfolded proteins in the ER lumen, which is a condition that is defined as ER stress, triggers the unfolded protein response (UPR). Since the UPR influences the extent of organ damage following hemorrhagic shock/reperfusion (HS/R) and mediates the protective effects of stress preconditioning before ischemia-reperfusion injury, the current study investigated the mechanisms of ER stress preconditioning and its impact on post-hemorrhagic liver damage. Male C56BL/6-mice were injected intraperitoneally with the ER stress inductor tunicamycin (TM) or its drug vehicle 48 h prior to being subjected to a 90 min pressure-controlled hemorrhagic shock (30±5 mmHg). A period of 14 h after hemorrhagic shock induction, mice were sacrificed. Hepatocellular damage was quantified by analyzing hepatic transaminases and hematoxylin-eosin stained liver tissue sections. Additionally, the topographic expression patterns of the ER stress marker binding immunoglobulin protein (BiP), UPR signaling pathways, and the autophagy marker Beclin1 were evaluated. TM injection significantly increased BiP expression and modified the topographic expression patterns of the UPR signaling proteins. In addition, immunohistochemical analysis of Beclin1 revealed an increased pericentral staining intensity following TM pretreatment. The histologic analysis of hepatocellular damage demonstrated a significant reduction in cell death areas in HS/R+TM (P=0.024). ER stress preconditioning influences the UPR and alleviates post-hemorrhagic liver damage. The beneficial effects were, at least partially, mediated by the upregulation of BiP and autophagy induction. These results underscore the importance of the UPR in the context of HS/R and may help identify novel therapeutic targets.

Abstract 143: The Modified Shock Index Separates Survivors from Non-Survivors in a Swine Model of Hemorrhagic Shock and Traumatic Brain Injury

The ratio between heart rate and arterial blood pressure during hemorrhagic shock has been shown useful to identify individuals at risk of death. We herein compared the index using the systolic arterial pressure (SI) and using the mean arterial pressure (MSI) along with other measurements including cardiac index and lactate in a swine model of hemorrhagic shock and traumatic brain injury developed to model injury in the battlefield. The parent study was designed to compare three different types of vasopressin agonists with control solution while practicing fluid-restricted resuscitation. The present analysis included 60 experiments focused on the initial 240 minutes with induction of hemorrhagic shock by liver laceration removing approximately 1,000 ml of blood in 30 minutes. Eight animals died during the acute phase and compare to 52 survivors, they had higher (median, IQR) MSI (4.6; 3.3 - 5.4 vs 2.5; 2.0 - 3.1; p < 0.001), SI (2.7; 2.1 - 3.1 vs 1.8; 1.6 - 2.2; p < 0.001), lower cardiac index (2.8; 2.3 - 3.4 vs 3.7; 3.2 - 4.2; p < 0.001), but no differences in lactate levels. Three of the eight non-survivors (37.5%) and 42 of the 52 survivors (80.1%) received a vasopressin analog (p = 0.019). Compared to other measurements of hemodynamic stability, monitoring the ratio between the heart rate and mean arterial pressure is a feasible and practical approach to deploy in various out of hospital settings including the battlefield as well as in civilian trauma. This approach could also guide interventions including the use of vasopressor agents, which our studies demonstrate having a survival effect during acute bleeding caused by hemorrhagic shock.

Moderately prolonged permissive hypotension results in reversible metabolic perturbation evaluated by intracerebral microdialysis - an experimental animal study

BackgroundDamage control resuscitation (DCR) and damage control surgery (DCS) is the main strategy in patients with uncontrollable hemorrhagic shock. One aspect of DCR is permissive hypotension. However, the duration of hypotension that can be tolerated without affecting the brain is unknown. In the present study we investigate the effect of 60 min severe hypotension on the brain’s energy metabolism and seek to verify earlier findings that venous cerebral blood can be used as a marker of global cerebral energy state.Material and methodsTen pigs were anaesthetized, and vital parameters recorded. Microdialysis catheters were placed in the left parietal lobe, femoral artery, and superior sagittal sinus for analysis of lactate, pyruvate, glucose, glycerol, and glutamate. Hemorrhagic shock was induced by bleeding the animal until mean arterial pressure (MAP) of 40 mmHg was achieved. After 60 min the pigs were resuscitated with autologous blood and observed for 3 h.ResultsAt baseline the lactate to pyruvate ratios (LP ratio) in the hemisphere, artery, and sagittal sinus were (median (interquartile range)) 13 (8–16), 21 (18–24), and 9 (6–22), respectively. After induction of hemorrhagic shock, the LP ratio from the left hemisphere in 9 pigs increased to levels indicating a reversible perturbation of cerebral energy metabolism 19 (12–30). The same pattern was seen in LP measurements from the femoral artery 28 (20–35) and sagittal sinus 22 (19–26). At the end of the experiment hemisphere, artery and sinus LP ratios were 16 (10–23), 17 (15–25), and 17 (10–27), respectively. Although hemisphere and sinus LP ratios decreased, they did not reach baseline levels (p < 0.05). In one pig hemisphere LP ratio increased to a level indicating irreversible metabolic perturbation (LP ratio > 200).ConclusionDuring 60 min of severe hypotension intracerebral microdialysis shows signs of perturbations of cerebral energy metabolism, and these changes trend towards baseline values after resuscitation. Sagittal sinus microdialysis values followed hemisphere values but were not distinguishable from systemic arterial values. Venous (jugular bulb) microdialysis might have a place in monitoring conditions where global cerebral ischemia is a risk.

Abstract 188: Investigation of the Mechanism of Action of Hydrogen Gas in Hemorrhagic Shock

Background: Molecular hydrogen gas (H 2 ) is known to alleviate ischemia-reperfusion injury; however, the mechanism of action involved remains unknown. Metabolome analysis of tissue subjected to ischemia-reperfusion injury has revealed xanthine oxidoreductase (XOR) as a candidate target molecule for H 2. Purpose: The effects of H 2 and the XOR inhibitor (XORi) on resuscitation after hemorrhagic shock (HS) were examined. Methods: Male Sprague-Dawley rats were subjected to HS by the withdrawal of blood to maintain a mean arterial pressure (MBP) of 35 mmHg for 60 minutes (T0 to T60). They were then resuscitated with lactated Ringer’s solution with 3 times the shed blood volume over 30 minutes (T60 to T90). The animals were randomly assigned into 3 groups: H 2 inhalation (1.3% H 2 ) from T30 (n=6), XORi administration (Topiroxostat 10 mg/kg, orally administered at 60 minutes before induction of HS) (n=5), and control (CTL) (n=5). The rats were observed until 2 hours after fluid resuscitation (T210). Results: Compared to that in the control group, the lactate level at 60 minutes after introduction of HS was lower in the XORi group, while the MBP after 2 hours of fluid resuscitation was higher in the H 2 group. XOR activity in the plasma, liver, kidney, and lung tissue was suppressed in the XORi group, but not in the H 2 group. Increased permeability of the pulmonary vasculature associated with increased levels of plasma inflammatory cytokines and plasma Syndecan-1 (a marker of endothelial glycocalyx degradation) after 2 hours of fluid resuscitation was ameliorated only in the H 2 group. Conclusion: The mechanisms of action possibly differ between H 2 and XORi. XORi confers resistance to ischemia by suppressing anaerobic glycolysis during ischemia. On the other hand, H 2 stabilizes hemodynamics via suppression of inflammation and vascular hyperpermeability after resuscitation.

In vivo performance of a visible wavelength optical sensor for monitoring intestinal perfusion and oxygenation

Traumatic injury resulting in hemorrhage is a prevalent cause of death worldwide. The current standard of care for trauma patients is to restore hemostasis by controlling bleeding and administering intravenous volume resuscitation. Adequate resuscitation to restore tissue blood flow and oxygenation is critical within the first hours following admission to assess severity and avoid complications. However, current clinical methods for guiding resuscitation are not sensitive or specific enough to adequately understand the patient condition. To better address the shortcomings of the current methods, an approach to monitor intestinal perfusion and oxygenation using a multiwavelength (470, 560, and 630nm) optical sensor has been developed based on photoplethysmography and reflectance spectroscopy. Specifically, two sensors were developed using three wavelengths to measure relative changes in the small intestine. Using vessel occlusion, systemic changes in oxygenation input, and induction of hemorrhagic shock, the capabilities and sensitivity of the sensor were explored in vivo. Pulsatile and nonpulsatile components of the red, blue, and green wavelength signals were analyzed for all three protocols (occlusion, systemic oxygenation changes, and shock) and were shown to differentiate perfusion and oxygenation changes in the jejunum. The blue and green signals produced better correlation to perfusion changes during occlusion and shock, while the red and blue signals, using a new correlation algorithm, produced better data for assessing changes in oxygenation induced both systemically and locally during shock. The conventional modulation ratio method was found to be an ineffective measure of oxygenation in the intestine due to noise and an algorithm was developed based on the Pearson correlation coefficient. The method utilized the difference in phase between two different wavelength signals to assess oxygen content. A combination of measures from the three wavelengths provided verification of oxygenation and perfusion states, and showed promise for the development of a clinical monitor.

Resuscitative therapy with erythropoietin reduces oxidative stress and inflammatory responses of vital organs in a rat severe fixed-volume hemorrhagic shock model

Hemorrhagic shock (HS) still has a high mortality rate and none of the known resuscitative regimens completely reverse its adverse outcomes. This study investigated the effects of different models of resuscitative therapy on the healing of organ damage in a HS model. Male Wistar rats were randomized into six groups: Sham, without HS induction; HS, without resuscitation; HS+Blood, resuscitation with the shed blood; HS+Blood+NS, resuscitation with blood and normal saline; HS+Blood+RL, resuscitation with blood and Ringer's lactate; EPO, erythropoietin was added to the blood and RL. Blood and urine samples were obtained 3 h after resuscitation. Kidney, liver and brain tissue samples were harvested for multiple organ failure evaluation. Survival rate was the highest in the Sham, EPO and HS+Blood+RL groups compared to others. Plasma creatinine concentration, ALT, AST, urinary NAG activity and renal NGAL mRNA expression significantly increased in the HS+Blood+RL group compared to the Sham group. There was a significant increase in tissue oxidative stress markers and pro-inflammatory cytokines in HS+Blood+RL group compared to the Sham rats. EPO had more protective effects on multiple organ failure compared to the HS+Blood+RL group. EPO, as a resuscitative treatment, attenuated HS-induced organ damage. It seems that it has a potential to be attractive for clinical trials.

Nephroprotection through the Akt/eNOS pathway by centrally administered erythropoietin in a rat model of fixed-volume hemorrhage

AimsThis study was designed to investigate the protective effects of centrally administered erythropoietin (EPO) on brain oxidative stress and inflammatory markers to protect the kidneys during hemorrhagic shock (HS). Main methodsAnimals were assigned into three groups (n=6). Sham rats were subjected to cannulation of femoral artery and vein as well as stereotaxic surgery. In HS group, 50% of total blood volume was withdrawn and resuscitation was started 2h later. In EPO group, stereotaxic surgery in lateral ventricle was performed one week before induction of HS for administration of EPO (2IU) just before resuscitation. Plasma samples, kidney and brain tissues were allocated after a further 3h in all animals. Key findingsThere was a significant increase in survival rate in the EPO group (69.3%) compared to the HS group (35.7%). Brain EPO administration significantly attenuated the rises in BUN, plasma Cr and NGAL, brain and renal MDA content and also increased SOD activity in the kidney and brain compared to the HS group. Brain, plasma and kidney TNF-α and IL-6 levels were significantly reduced by EPO compared to HS group. EPO increased the phosphorylation of Akt on Ser473 and eNOS mRNA expression in the kidney tissue compared to the HS group. SignificanceIn conclusion, centrally administered EPO reduced pro-inflammatory and oxidative stress indices in the kidney and reduced apoptosis by activation of the Akt/eNOS signaling pathway. Hence, it can be hypothesized that EPO may play a major role in the central regulation of renal system as a neuromodulator.

Dose-dependent effects of peroxisome proliferator-activated receptors β/δ agonist on systemic inflammation after haemorrhagic shock

IntroductionPPARβ/δ agonists are known to modulate the systemic inflammatory response after sepsis. In this study, inflammation modulation effects of PPARβ/δ are investigated using the selective PPARβ/δ agonist (GW0742) in a model of haemorrhagic shock (HS)-induced sterile systemic inflammation. MethodsBlood pressure-controlled (35±5mmHg) HS was performed in C57/BL6 mice for 90min. Low-dose GW0742 (0.03mg/kg/BW) and high-dose GW0742 (0.3mg/kg/BW) were then administered at the beginning of resuscitation. Mice were sacrificed 6h after induction of HS. Plasma levels of IL-6, IL-1β, IL-10, TNFα, KC, MCP-1, and GM-CSF were determined by ELISA. Myeloperoxidase (MPO) activity in pulmonary and liver tissues was analysed with standardised MPO kits. ResultsIn mice treated with high-dose GW0742, plasma levels of IL-6, IL-1β, and MCP-1 were significantly increased compared to the control group mice. When compared to mice treated with low-dose GW0742 plasma levels of IL-6, IL-1β, GM-CSF, KC, and MCP-1 were significantly elevated in high-dose-treated mice. Low-dose GW0742 treatment was associated with a non-significant downtrend of inflammatory factors in mice with HS. No significant changes of MPO activity in lung and liver were observed between the control group and the GW0742 treatment groups. ConclusionThis study identified dose-dependent effects of GW0742 on systemic inflammation after HS. While high-dose GW0742 substantially enhanced the systemic inflammatory response, low-dose GW0742 led to a downtrend of pro-inflammation cytokine expression. The exact mechanisms are yet unknown and need to be assessed in further studies.

Renal tissue pro-inflammatory gene expression is reduced by erythropoietin in rats subjected to hemorrhagic shock.

BackgroundHemorrhagic shock (HS) is a condition produced by considerable loss of intravascular volume, which may eventually lead to organ damage and death.ObjectivesIn the present study, the potential implication of the kidney tissue tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and interleukin-10 (IL-10) were evaluated in the protective effects of erythropoietin (EPO) during HS.Materials and MethodsMale Wistar rats were randomized into three experimental groups; Sham, HS (hemorrhagic shock and resuscitation), and EPO (erythropoietin). HS was induced by 50% blood volume hemorrhage over 30 minutes. After 2 hours, resuscitation was performed within 30 minutes. In the EPO group, EPO (300 IU/kg, i.v.) was administered 10 minutes before HS induction. Urine was collected to determine urinary N-acetyl-β-D-glucosaminidase (NAG) activity level. The kidney cytokines (TNF-α, IL-6 and IL-10) mRNA expressions were measured by real-time polymerase chain reaction (PCR).ResultsHS rats showed significant increase in urinary NAG activity compared to the sham group. EPO significantly attenuated the rises in urinary NAG activity compared to the HS group. In the HS animals, renal TNF-α and IL-6 mRNA expressions increased whereas no difference was observed in IL-10 mRNA expression between the HS and sham groups. EPO was able to decrease renal TNF-α and IL-6 production and increase IL-10 mRNA expression.ConclusionsIn this study, we demonstrated that EPO attenuates kidney damage in rats subjected to HS. The beneficial effects of EPO may be at least partly mediated by modifications in the inflammatory cascade.

Effects of etomidate in the adrenal and cytokine responses to hemorrhagic shock in rats

Hemorrhagic shock (HS) induces a compensatory endocrine and cytokine response which aims to restore homeostasis. This response can be modulated by general anesthetics. To our knowledge, no studies have evaluated if etomidate modulates this response in experimental HS. After being premedicated with buprenorphine (0.05 mg/kg subcutaneously), male Wistar rats were anaesthetized with 5% isoflurane and divided into three groups: G1 (control, n = 16), G2 (n = 13), and G3 (n = 14). G2 and G3 were subjected to HS by collecting 30% of their blood volume and resuscitated 90 min later with the collected blood and normal saline, in a 1:3 ratio, respectively. G3 received etomidate (1 mg/kg IV) before HS. Blood gas analysis, adrenocorticotropic hormone (ACTH), corticosterone, and plasma levels of tumor necrosis factor (TNF)-α, interleukin (IL)-6, IL-10 and of TNF-α, IL-6, and IL-10 mRNA obtained through real-time polymerase chain reaction (RT-PCR) were measured at 0, 90, 150, and 240 min after HS induction. Compared with G2, etomidate-treated animals had significantly lower corticosterone, PO2, PO2/FiO2, base excess and HCO3, and higher TNF-α, IL-6, IL-10, and TNF-α mRNA levels ( P &lt;0.05). Etomidate-treated rats showed impaired adrenal and increased cytokine response to HS and evidence of worse tissue oxygenation and lung dysfunction. Based on these results, and until further studies are performed to confirm if these findings occur in clinical patients, we suggest that etomidate should be used cautiously in HS.

Vasopressin analog terlipressin attenuates kidney injury in hemorrhagic shock.

BackgroundIn hemorrhagic shock (HS), volume replacement with crystalloid solution can restore the hemodynamic status and decrease mortality. However, it can also lead to tissue edema and pulmonary congestion, as well as increasing vascular permeability. Here, we analyzed the effects that resuscitation with lactated Ringer's solution (LRS) or administration of the vasopressin analog terlipressin has on renal function in a porcine model of HS.MethodsUsing pressure-controlled bleeding, we induced pigs to HS, maintaining mean arterial pressure (MAP) at 40 mm Hg for 30 min. Animals were divided into 4 groups: sham (anesthesia only); shock-only (HS induction); shock+LRS (HS induction and subsequent resuscitation with LRS at 3 times the volume of blood removed); and shock+Terli (HS induction and subsequent bolus administration of 2 mg of terlipressin). Parameters were evaluated at baseline, then at 30, 60, and 120 min after treatment (T30, T60, and T120, respectively). Animals were euthanized at T60 or T120.ResultsBoth treatments restored MAP to baseline values. At T30 and T60, creatinine clearance was highest in shock+LRS pigs, whereas it was highest in shock+Terli pigs at T120. Both treatments initially induced hyponatremia, although urinary excretion of all ions was higher in shock+LRS pigs at T30. Both treatments restored Na–K–2Cl cotransporter expression, whereas only terlipressin restored aquaporin 2 expression. Both treatments also prevented HS-induced acute tubular necrosis. Expression of the vasopressin receptors V1a and V2 was highest in shock-only pigs. At T120, V1a expression was lowest in shock+LRS pigs.DiscussionTerlipressin might be useful for preventing HS-induced acute kidney injury.

Gradually increased oxygen administration promoted survival after hemorrhagic shock.

Gradually increased oxygen administration (GIOA) seems promising in hemorrhagic shock. However, the effects of GIOA on survival remain unclear, and details of GIOA are to be identified. After the induction of hemorrhagic shock, the rats were randomized into five groups (n = 9): normoxic group (Normo), hyperoxic group (Hypero), normoxic to hyperoxic group (GIOA1), long-time hypoxemic to hyperoxic group (GIOA2), and short-time hypoxemic to hyperoxic group (GIOA3). Survival was recorded for 96 h, plasma alanine transaminase, oxidative stress, hemodynamics, and blood gas were measured. The mean survival time of the GIOA3 was significantly longer than that of the Normo, Hypero, and GIOA2. Plasma alanine transaminase levels were significantly lower in the Normo, GIOA1, and GIOA3 compared to the Hypero and GIOA2 at 2 h post-resuscitation (PR). Plasma 3-nitrotyrosine levels at 2 h PR were significantly lower in the GIOA2 and GIOA3 compared to the Normo and Hypero. Central venous oxygen saturation at 2 h PR in the GIOA3 was significantly higher than the Normo; however, no significant difference was observed between GIOA1 and Normo. Besides, at 2 h PR, mean arterial pressure in the GIOA3 was significantly higher than the GIOA2; however, no significant difference was observed between GIOA1 and GIOA2. (1) GIOA could significantly prolong survival time compared to normoxemic resuscitation and hyperoxic resuscitation; (2) early moments of GIOA are critical to the benefits; and (3) hypoxemia at onset of resuscitation may be imperative, more works are needed to determine the optimal initial oxygen concentration of GIOA.

Calcitriol decreases pro-inflammatory cytokines and protects against severe hemorrhagic shock induced-organ damage in rats

IntroductionResuscitation after hemorrhagic shock (HS) could result in increased pro-inflammatory cytokines and then multiple organ dysfunctions. Calcitriol exerts pleiotropic effects in a wide variety of target tissues and has a role against anti-inflammation. The present study was aimed to investigate the modulatory effects of calcitriol on the pathophysiological and inflammatory markers following HS in rats. Materials and methodsBy withdrawing 60% of the total blood volume over 30min via a femoral artery catheter in rats, HS was induced. Afterwards, 10ng/kg calcitriol was injected intravenously in rats. After performing these procedures, hemodynamic status of mean arterial pressure (MAP) and heart rate (HR) were continuously monitored for 12h. Hemoglobin, lactic dehydrogenase (LDH), creatine phosphokinase (CPK), liver and renal function were measured at 30min before the induction of HS and 0, 1, 3, 6, 9, and 12h after HS, while an equal volume of normal saline as replacement fluid. At 1 and 12h after inducing HS, serum levels of tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6) levels were measured, and the livers, kidneys and lungs were taken out and then examined histo-pathologically at 48h after inducing HS. ResultsHemoglobin and MAP were significantly decreased, liver and renal function were significantly impaired, but HR and the levels of LDH, CPK, TNF-α and IL-6 were significantly increased after HS in rats. After being treated with calcitriol following HS resulted in better survival rate, lower serum levels of TNF-α and IL-6, and lesser hepatic, renal, and pulmonary histo-pathologic scores of injury in rats. ConclusionBeing treated with calcitriol after HS could ameliorate the pro-inflammatory reactions by modulating the effects of cytokines, which lead to prevention of subsequent major organ damages.

The therapeutic effect and mechanism of niacin on acute lung injury in a rat model of hemorrhagic shock: Down-regulation of the reactive oxygen species-dependent nuclear factor κB pathway.

The purpose of the current study was to investigate the protective effect of niacin on acute lung injury by the down-regulation of the nuclear factor κB (NF-κB) pathway in hemorrhagic shock (HS) rats. HS was induced in male Sprague-Dawley rats by withdrawing blood to maintain a mean arterial pressure of 20 mm Hg to 25 mm Hg for 40 minutes. The rats were resuscitated by the reinfusion of the drawn blood, and a vehicle (HS), a low-dose of niacin (360 mg/kg, HS + LD-NA), or a high dose of niacin (1,080 mg/kg, HS + HD-NA) were administered orally. The survival of the subjects was observed for 72 hours, and a separate set of animals was killed at 6 hours after HS induction. We measured cytoplasmic phosphorylated inhibitor κB-α and inhibitor κB-α expressions, nuclear NF-κB p65 expression, NF-κB p65 DNA-binding activity, MEK partner 1 activity, tumor necrosis factor α (TNF-α), interleukin 6 (IL-6), IL-8, nicotinamide adenine dinucleotide (NAD+), reduced nicotinamide adenine dinucleotide phosphate, reduced glutathione, glutathione disulfide, malondialdehyde levels, and histologic damage in the lung tissue. We also measured TNF-α, IL-6, and IL-8 levels in the serum. The survival rates of the sham, HS, HS + LD-NA, and HS + HD-NA groups were 6 of 6 (100%), 0 of 9 (0%), 1 of 9 (11.1%), and 3 of 9 (33.3%), respectively. A high dose of niacin increased lung NAD+, nicotinamide adenine dinucleotide phosphate levels, and glutathione-glutathione disulfide ratios; decreased lung malondialdehyde levels; down-regulated the NF-κB pathway; suppressed TNF-α, IL-6, and IL-8 levels in the lung tissue and serum; and attenuated histologic lung damage. A high dose of niacin attenuated lung inflammation, suppressed proinflammatory cytokine release, reduced histologic lung damage, and improved survival after HS in rats. Its therapeutic benefits were associated with the down-regulation of the reactive oxygen species-dependent NF-κB pathway.

Inhibition of glycogen synthase kinase (GSK)-3-β improves liver microcirculation and hepatocellular function after hemorrhagic shock

Ischemia and reperfusion may cause liver injury and are characterized by hepatic microperfusion failure and a decreased hepatocellular function. Inhibition of glycogen synthase kinase (GSK)-3β, a serine-threonine kinase that has recently emerged as a key regulator in the modulation of the inflammatory response after stress events, may be protective in conditions like sepsis, inflammation and shock. Therefore, aim of the study was to assess the role of GSK-3β in liver microcirculation and hepatocellular function after hemorrhagic shock and resuscitation (H/R). Anesthetized male Sprague-Dawley rats underwent pretreatment with Ringer´s solution, vehicle (DMSO) or TDZD-8 (1mg/kg), a selective GSK-3β inhibitor, 30min before induction of hemorrhagic shock (mean arterial pressure 35±5mmHg for 90min) and were resuscitated with shed blood and Ringer´s solution (2h). 5h after resuscitation hepatic microcirculation was assessed by intravital microscopy. Propidium iodide (PI) positive cells, liver enzymes and alpha-GST were measured as indicators of hepatic injury. Liver function was estimated by assessment of indocyanine green plasma disappearance rate. H/R led to a significant decrease in sinusoidal diameters and impairment of liver function compared to sham operation. Furthermore, the number of PI positive cells in the liver as well as serum activities of liver enzymes and alpha-GST increased significantly after H/R. Pretreatment with TDZD-8 prevented the changes in liver microcirculation, hepatocellular injury and liver function after H/R. A significant rise in the plasma level of IL-10 was observed. Thus, inhibition of GSK-3β before hemorrhagic shock modulates the inflammatory response and improves hepatic microcirculation and hepatocellular function.

Heavy Ethanol Intoxication Increases Proinflammatory Cytokines and Aggravates Hemorrhagic Shock-Induced Organ Damage in Rats

Hemorrhagic shock (HS) following acute alcohol intoxication can increase proinflammatory cytokine production and induce marked immunosuppression. We investigated the effects of ethanol on physiopathology and cytokine levels following HS in acutely alcohol-intoxicated rats. Rats received an intravenous injection of 5 g/kg ethanol over 3 h followed by HS induced by withdrawal of 40% of total blood volume from a femoral arterial catheter over 30 min. Mean arterial pressure (MAP) and heart rate (HR) were monitored continuously for 48 h after the start of blood withdrawal. Biochemical parameters, including hemoglobin, ethanol, glutamic oxaloacetic transaminase (GOT), glutamic pyruvic transaminase (GPT), blood urea nitrogen (BUN), creatinine (Cre), lactic dehydrogenase (LDH), and creatine phosphokinase (CPK), were measured at 30 min before induction of HS and 0, 1, 3, 6, 9, 12, 18, 24, and 48 h after HS. Serum tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) levels were measured at 1 and 12 h after HS. The liver, kidneys, and lungs were removed for pathology at 48 h later. HS significantly increased HR, blood GOT, GPT, BUN, Cre, LDH, CPK, TNF-α, and IL-6 levels and decreased hemoglobin and MAP in rats. Acute ethanol intoxication further increased serum levels of GOT, GPT, BUN, Cre, LDH, CPK, TNF-α and IL-6 elevation following HS. Acutely intoxicated rats exacerbated the histopathologic changes in the liver, kidneys, and lungs following HS.

MALP-2 pre-treatment modulates systemic inflammation in hemorrhagic shock

BackgroundTLR-2 is expressed on the surface of leucocytes, lung and liver tissue and initiates the activation of immune response after interaction with components of the bacterial cell wall. In this experiment we investigated whether immunostimulation with TLR-2 agonists under conditions of sterile inflammation (hemorrhagic shock (HS)) may affect the immune response and remote organ inflammation.MethodsMale C57/BL6 mice were subjected to standardized pressure-controlled HS (MAP of 35 mmHg for 90 minutes). The TLR-2 agonist macrophage-activated lipopeptide-2 (MALP-2) was administered (i.p.) either 12 hours prior to the induction of HS (Group MALP PT) or after the hypotensive period (90 minutes) (Group MALP T). After six hours, plasma cytokine levels (IL-6, KC, IL-10, and MCP-1) and lung and liver MPO activity were assessed.ResultsPre-treatment with MALP-2 resulted in a significant attenuation of the systemic pro-inflammatory (IL-6) response (MALP PT: 0.83±0.2 ng/ml vs. MALP T: 1.7±0.09 ng/ml) (p<0.05). In comparison to the liver MPO activity, lung MPO levels in in group MALP PT did not show differences to levels measured in MALP T mice (1.200±200 ng/mg vs. 1.800±200 ng/mg).ConclusionsAfter initial inflammation, MALP-2 pre-treatment was associated with attenuated systemic immune response after sterile stimulus. The TLR-2 agonist appears to affect sterile inflammation pathways. The exact mechanisms should be studied further to better understand these affects.