Oxidative stress causes nuclear factor-kappaB activation in acute hypovolemic hemorrhagic shock

Targeting Inflammation After Hemorrhagic Shock as a Molecular and Experimental Journey to Improve Outcomes: A Review

Hemorrhagic shock continues to be a major contributor to trauma-related fatalities globally, posing a significant and intricate pathophysiological challenge. The condition is marked by injury and blood loss, which activate molecular cascades that can quickly become harmful. The inflammatory response exhibits a biphasic pattern, beginning with a hyper-inflammatory phase that transitions into immunosuppression, posing significant obstacles to effective therapeutic interventions. This review article explores the intricate molecular mechanisms driving inflammation in hemorrhagic shock, emphasizing cellular signaling pathways, endothelial dysfunction, and immune activation. We discuss the role of molecular biomarkers in tracking disease progression and stratifying risk, with a focus on markers of endothelial dysfunction and inflammatory mediators as potential prognostic tools. Additionally, we assess therapeutic strategies, spanning traditional approaches like hemostatic resuscitation to advanced immunomodulatory treatments. Despite promising advancements in molecular monitoring and targeted therapies, challenges persist in bridging experimental findings with clinical applications. Future efforts must prioritize understanding the dynamic progression of inflammatory pathways and refining the timing of interventions to improve outcomes in hemorrhagic shock management.

Navigating Hemorrhagic Shock: Biomarkers, Therapies, and Challenges in Clinical Care

Hemorrhagic shock remains a leading cause of preventable death worldwide, with mortality patterns varying significantly based on injury mechanisms and severity. This comprehensive review examines the complex pathophysiology of hemorrhagic shock, focusing on the temporal evolution of inflammatory responses, biomarker utility, and evidence-based therapeutic interventions. The inflammatory cascade progresses through distinct phases, beginning with tissue injury and endothelial activation, followed by a systemic inflammatory response that can transition to devastating immunosuppression. Recent advances have revealed pattern-specific responses between penetrating and blunt trauma, necessitating tailored therapeutic approaches. While damage control resuscitation principles and balanced blood product administration have improved outcomes, many molecular targeted therapies remain investigational. Current evidence supports early hemorrhage control, appropriate blood product ratios, and time-sensitive interventions like tranexamic acid administration. However, challenges persist in biomarker validation, therapeutic timing, and implementation of personalized treatment strategies. Future directions include developing precision medicine approaches, real-time monitoring systems, and novel therapeutic modalities while addressing practical implementation barriers across different healthcare settings. Success in hemorrhagic shock management increasingly depends on integrating multiple interventions across different time points while maintaining focus on patient-centered outcomes.

Pachymic Acid Prevents Hemorrhagic Shock-Induced Cardiac Injury by Suppressing M1 Macrophage Polarization and NF-[Formula: see text]B Signaling Pathway

Hemorrhagic shock (HS) is the leading cause of death in trauma patients. Inflammation following HS can lead to cardiac damage. Pachymic acid (PA), a triterpenoid extracted from Poria cocos, has been found to possess various biological activities, including anti-inflammatory and anti-apoptotic properties. Our research aims to investigate the protective effects of PA against HS-induced heart damage and the underlying mechanisms involved. Male Sprague-Dawley rats were intraperitoneally injected with PA (7.5 or 15[Formula: see text]mg/kg) daily for three days. Subsequently, we created a rat model of HS by drawing blood through a catheter inserted into the femoral artery followed by resuscitation. The results revealed that HS led to abnormalities in hemodynamics, serum cardiac enzyme levels, and cardiac structure, as well as induced cardiac apoptosis. However, pretreatment with PA effectively alleviated these effects. PA-pretreatment also suppressed mRNA and protein levels of interleukin (IL)-1[Formula: see text], IL-6, and tumor necrosis factor [Formula: see text] (TNF-[Formula: see text]) in the heart tissues of HS rats. Additionally, PA-pretreatment reduced inflammatory cell infiltration and M1 macrophage polarization while exaggerating M2 polarization in HS rat hearts. The study observed a decreased proportion of the expression of of M1 macrophages (CD86[Formula: see text]) and their marker (iNOS), along with an increased proportion of the expression of M2 macrophages (CD206[Formula: see text]) and their marker (Arg-1). Notably, PA-pretreatment suppressed NF-[Formula: see text]B pathway activation via inhibiting NF-[Formula: see text]B p65 phosphorylation and its nuclear translocation. In conclusion, PA-pretreatment ameliorates HS-induced cardiac injury, potentially through its inhibition of the NF-[Formula: see text]B pathway. Therefore, PA treatment holds promise as a strategy for mitigating cardiac damage in HS.

Study of the correlation between the expression of nuclear factor kappa B and proliferation regulatory proteins and chronic superficial gastritis

Background/Aim. Cell proliferation and the regulation of protein expression play an important role in gastritis, but in chronic superficial gastritis (CSG), they are rarely reported. The aim of this study was to determine the relationship between the expression of nuclear factor kappa B (NF-?B) and regulatory proteins and the rat CSG. Methods. The CSG rat model was established artificially, by chemical agents and irregular diet. The expression of epidermal growth factor receptor (EGFR) and proliferating cell nuclear antigen (PCNA) in the gastric mucosa of CSG rats was measured by immunohistochemistry, while mRNA expression levels of NF-?B p65 were detected by in situ hybridization. Results. There was more obvious infiltration of inflammatory cells in the gastric mucosa of CSG rats than in that of control rats, and the inflammation score was significantly increased. The expression levels of PCNA, EGFR, and NF-?B p65 mRNA in the gastric mucosal cells of CSG model rats increased significantly. Correlation analysis showed that the inflammation score was positively correlated with the expression levels of NF-?B p65 mRNA and EGFR, while it presented no significant correlation with the expression level of PCNA. In addition, there was a significant positive correlation between NF-?B p65 mRNA and EGFR levels. Conclusion. High expression of NF-?B and EGFR plays an important role in the occurrence and progression of CSG, and it is significantly positively correlated with the degree of inflammation in the gastric mucosa. Therefore, changes in NF-?B and EGFR expression may be used as important indicators for the assessment of CSG; changes in their expression levels are helpful to assess the degree of gastric mucosal lesions and progression of CSG.

Involvement of Toll-Like Receptor 4 in Decreased Vasopressor Response Following Trauma/Hemorrhagic Shock

OBJECTIVES:

Refractory vascular failure due to the inability of vascular smooth muscle to respond to vasoconstrictors such as phenylephrine is a final common pathway for severe circulatory shock of any cause, including trauma/hemorrhagic shock. Increased inflammation, Toll-like receptor 4 activation, and decreased response of the alpha-1 adrenergic receptors which control vascular tone have been reported in trauma/hemorrhagic shock.

HYPOTHESIS:

In trauma/hemorrhagic shock, Toll-like receptor 4 activation contributes to vascular failure via decreased bioavailability of adrenergic receptors.

DESIGN AND MEASUREMENTS:

Trauma/hemorrhagic shock was induced in Wistar rats (laparotomy combined with mean arterial pressure at 40 mm Hg for 90 min followed by 2 hr resuscitation with Lactated Ringers solution). To inhibit Toll-like receptor 4, resatorvid (TAK-242) and resveratrol were used, and plasma was collected. Smooth muscle cells were incubated with lipopolysaccharide (10 ng/mL) or plasma. Inflammatory cytokines were screened using dot-blot. Toll-like receptor 4 and nuclear factor κB activation and cellular localization of the alpha-1 adrenergic receptor were measured by immunofluorescence imaging and Western blot analysis. Clustered regularly interspaced short palindromic repeats/Cas9 was used to knock out Toll-like receptor 4, and calcium influx following stimulation with phenylephrine was recorded.

MAIN RESULTS:

Trauma/hemorrhagic shock caused a decreased response to phenylephrine, whereas Toll-like receptor 4 inhibition improved blood pressure. Trauma/hemorrhagic shock plasma activated the Toll-like receptor 4/nuclear factor κB pathway in smooth muscle cells. Double labeling of Toll-like receptor 4 and the alpha-1 adrenergic receptor showed that these receptors are colocalized on the cell membrane. Activation of Toll-like receptor 4 caused cointernalization of both receptors. Calcium influx was impaired in cells incubated with trauma/hemorrhagic shock plasma but restored when Toll-like receptor 4 was knocked out or inhibited.

CONCLUSIONS:

Activation of the Toll-like receptor 4 desensitizes vascular smooth muscle cells to vasopressors in experimental trauma/hemorrhagic shock by reducing the levels of membrane alpha-1 adrenergic receptor.

Interventional vitamin C: A strategy for attenuation of coagulopathy and inflammation in a swine multiple injuries model

BACKGROUND

Coagulopathy and inflammation induced by hemorrhagic shock and traumatic injury are associated with increased mortality and morbidity. Vitamin C (VitC) is an antioxidant with potential protective effects on the proinflammatory and procoagulant pathways. We hypothesized that high-dose VitC administered as a supplement to fluid resuscitation would attenuate inflammation, coagulation dysfunction, and end-organ tissue damage in a swine model of multiple injuries and hemorrhage.

METHODS

Male Sinclair swine (n = 24; mean body weight, 27 kg) were anesthetized, intubated, mechanically ventilated, and instrumented for physiologic monitoring. Following stabilization, swine were subjected to shock/traumatic injury (hypothermia, liver ischemia and reperfusion, comminuted femur fracture, hemorrhagic hypotension), resuscitated with 500 mL of hydroxyethyl starch, and randomized to receive either intravenous normal saline (NS), low-dose VitC (50 mg/kg; LO), or high-dose VitC (200 mg/kg; HI). Hemodynamics, blood chemistry, hematology, and coagulation function (ROTEM) were monitored to 4 hours postresuscitation. Histological and molecular analyses were obtained for liver, kidney, and lung.

RESULTS

Compared with VitC animals, NS swine showed significant histological end-organ damage, elevated acute lung injury scores, and increased mRNA expression of tissue proinflammatory mediators (IL-1β, IL-8, TNFα), plasminogen activation inhibitor-1 and tissue factor. There were no statistically significant differences between treatment groups on mean arterial pressure or univariate measures of coagulation function; however, NS showed impaired multivariate clotting function at 4 hours.

CONCLUSION

Although correction of coagulation dysfunction was modest, intravenous high-dose VitC may mitigate the proinflammatory/procoagulant response that contributes to multiple organ failure following acute severe multiple injuries.

LEVEL OF EVIDENCE

Prospective randomized controlled blinded trial study, Preclinical (animal-based).

Inhibition of Inflammatory Response by Crocin Attenuates Hemorrhagic Shock-Induced Organ Damages in Rats

Hemorrhagic shock (HS) is associated with an excessive activation of inflammation, contributing to multiple organ failure in numerous medical or surgical conditions. To explore the therapeutic potential of crocin, a natural compound with anti-inflammatory properties, we administered crocin to rats during resuscitation following HS induced by withdrawing blood. Compared with control animals which were sham-treated, HS-operated rats showed organ damages as manifested by enhanced markers of multiple organ dysfunctions. Crocin treatment substantially reduced these parameters in rats subjected to HS, suggesting an alleviation of tissue injuries such as in the kidney, liver, pancreas, and muscle. The activation of NF-κB (nuclear factor κB) pathway in lung tissue by HS, as shown by increased nuclear translocation of p65 and IκBα phosphorylation, was diminished by crocin treatment. The crocin administration also significantly decreased the serum levels of proinflammatory cytokine TNF-α (tumor necrosis factor-α) and interleukin (IL)-6, whereas increased the level of anti-inflammatory cytokine IL-10 in HS-operated rats. These studies indicate that crocin administration may reduce inflammation-driven tissue damage in patients with HS.

Carboxyfullerene nanoparticles alleviate acute hepatic injury in severe hemorrhagic shock

Hemorrhagic shock/resuscitation involves overwhelming reactive oxygen species (ROS) that cause oxidative stress, inflammation, and subsequent tissue injury. We investigated the effects of the potent antioxidant carboxyfullerene (C3) on acute liver injury during hemorrhage shock/resuscitation. C3 infusion reduced the alanine aminotransferase (ALT) activity, methemoglobin content, malondialdehyde content, myeloperoxidase activity and expression levels of tumor necrosis factor -α and interleukin-6; it increased superoxide dismutase activity in the liver. The histologic injury score and apoptotic index were also markedly decreased after C3 treatment compared with the vehicle group. Additionally, C3-treated rats showed a significant decrease in nuclear factor-κB DNA binding capacity, which was preceded by reduced phosphorylation of the nuclear factor κB (NF-κB) p65 subunit in the liver. C3 nanoparticles ameliorate oxidative stress, the inflammatory response, and subsequent acute liver injury after hemorrhagic shock/resuscitation. These protective effects appear to be mediated through the inhibition of the nuclear factor-κB pathway. C3 treatment may be a promising strategy to improve tissue injury in hemorrhagic shock/resuscitation.

Controlled moderate hypovolaemia in healthy volunteers is not associated with the development of oxidative stress assessed by plasma F2-isoprostanes and isofurans

Hypovolaemia can be associated with substantial morbidity, particularly when it occurs in the setting of trauma and in patients with comorbid diseases. Hypovolaemia and inflammation such as occur in the setting of trauma and surgery, are associated with systemic oxidative stress and free-radical injury. Free-radical injury that results from hypovolaemia-induced organ reperfusion may further augment inflammatory processes. It is unknown exactly what proportion of free-radical injury is associated with isolated hypovolaemia as opposed to the contribution from inflammation from surgery or trauma. In the first human study of its kind, we exposed 8 adult male volunteers to venesection-induced hypovolaemia in progressive aliquots of 5% of total blood volume until 20% had been removed. This blood was subsequently reinfused. Plasma F2-isoprostanes and isofurans, markers of in vivo lipid oxidation, were measured by gas chromatography-mass spectrometry at each 5% aliquot venesected and at each 5% reinfused. Between baseline and maximal blood loss there was a minor fall in haemoglobin concentration from 143.9g/l to 138.8g/l (p=0.004, 95% CI 2.2, 8.0g/L). No significant change from baseline occurred in the concentrations of either plasma F2-isoprostanes or isofurans during venesection (p=0.116 and p=0.152, respectively) or blood reinfusion (p=0.553 and p=0.736, respectively). We can conclude that in healthy adult volunteers, isolated hypovolaemia to 20% total blood volume loss is not associated with detectable systemic oxidative stress. The free-radical injury identified in surgical and trauma patients may represent the effects of tissue damage and inflammation, with an uncertain contribution from tissue ischemia as may occur with hypovolaemia.

The Expression of Nuclear Transcription Factor Kappa B (NF-κB) in the Case of Critically Ill Polytrauma Patients with Sepsis and Its Interactions with microRNAs

Critical polytrauma patients present a series of pathophysiological disturbances, biochemical and molecular dysfunction, which comprise to be the major cause of intensive care unit admission. In regard to molecular damage, there exists a series of factors, which all together contribute to the aggravation of the clinical status leading to increased mortality rate in these patients. One of the most important biochemical factors involved is the nuclear transcription factor B (NF-κB). Impaired NF-κB functioning is reflected on the clinical status of the patient through increased production of pro-inflammatory molecule, leading to multiple organ dysfunction syndrome. In addition to this, through microRNAs interactions, various pathophysiological as well as biochemical disturbances are produced, which altogether further reduce the patient's survival rate. In this paper, we would like to present the modifications seen in the expression of NF-κB in critically polytraumatized patients with sepsis. In additions to this, we would like to discuss the correlation between the microRNAs and its further implications in clinical status of these patients.

Persistent reduced oxygen requirement following blood transfusion during recovery from hemorrhagic shock

Our study intended to determine the effects on oxygen uptake (VO2) of restoring a normal rate of O2 delivery following blood transfusion (BT) after a severe hemorrhage (H). Spontaneously breathing urethane anesthetized rats were bled by removing 20 ml/kg of blood over 30 min. Rats were then infused with their own shed blood 15 min after the end of H. At mid-perfusion, half of the rats received a unique infusion of the decoupling agent 2,4-dinitrophenol (DNP, 6 mg/kg). VO2 and arterial blood pressure (ABP) were continuously measured throughout the study, along with serial determination of blood lactate concentration [La]. Animals were euthanized 45 min after the end of reperfusion; liver and lungs were further analyzed for early expression of oxidative stress gene using RT-PCR. Our bleeding protocol induced a significant decrease in ABP and increase in [La], while VO2 dropped by half. The O2 deficit progressively accumulated during the period of bleeding reached -114 ± 53 ml/kg, just before blood transfusion. Despite the transfusion of blood, a significant O2 deficit persisted (-82 ± 59 ml/kg) 45 min after reperfusion. This slow recovery of VO2 was sped up by DNP injection, leading to a fast recovery of O2 deficit after reperfusion, becoming positive (+460 ± 132 ml/kg) by the end of the protocol, supporting the view that O2 supply is not the main controller of VO2 dynamics after BT. Of note is that DNP also enhanced oxidative stress gene expression (up-regulation of NADPH oxidase 4 in the lung for instance). The mechanism of slow recovery of O2 requirement/demand following BT and the resulting effects on tissues exposed to relatively high O2 partial pressure are discussed.

Kaempferol pretreatment modulates systemic inflammation and oxidative stress following hemorrhagic shock in mice

Background

Kaempferol has been reported as beneficial for both acute and chronic inflammatory diseases. This study aims to investigate whether kaempferol affects systemic inflammation and oxidative stress in the heart, lung, and liver after hemorrhagic shock in mice.

Methods

Male C57/BL6 mice underwent hemorrhagic shock (mean arterial pressure of 35 mmHg for 90 min) and were arbitrarily divided into Sham, hemorrhagic shock (HS), and Kae groups (n = 10 in each group). Mice in the Kae groups received a kaempferol (10-mg/kg body weight) injection 12 h prior to (Group Kae PT) or 90 min after (Group Kae T) the initiation of hemorrhagic shock. Plasma proinflammatory cytokines (TNF-α and IL-6), organ myeloperoxidase (MPO) and superoxide dismutase (SOD) activities, and organ malondialdehyde (MDA) concentrations and heme oxygenase-1 (HO-1) expression levels were assessed by enzyme-linked immunosorbent assay (ELISA) or western blot assay.

Results

Compared with the HS group and the Kae T group, pretreatment with kaempferol significantly decreased proinflammatory cytokines TNF-α (P = 0.012 and 0.015, respectively) and IL-6 (P = 0.023 and 0.014, respectively) following hemorrhagic shock. Kae pretreatment reverted MPO, SOD, and MDA to basal levels in the heart, lung, and liver (Ps < 0.05), while the Kae T group showed no significant differences in these biomarkers compared with the HS group (Ps > 0.05). HO-1 expression was significantly increased in the Kae PT group compared with the other groups (P = 0.011 vs. HS group and P = 0.02 vs. Kae T group).

Conclusions

Pretreatment of hemorrhagic shock mice with kaempferol significantly decreased plasma levels of TNF-α and IL-6; reverted MPO, SOD, and MDA in the heart, lung, and liver; and increased expression of HO-1 in the same organs.

Impact of β-adrenoceptor blockade on systemic inflammation and coagulation disturbances in rats with acute traumatic coagulopathy

BACKGROUND

Sympathetic hyperactivity occurs early in acute traumatic coagulopathy (ATC) and is closely related to its development. β-adrenoceptor antagonists are known to alleviate adverse sympathetic effects and improve outcome in various diseases. We investigated whether β-blockers have protective effects against inflammation and endothelial and hemostatic disorders in ATC.

MATERIAL AND METHODS

ATC was induced in male Sprague-Dawley rats by trauma and hemorrhagic shock. Rats were randomly assigned to the sham, ATCC (ATC control), and ATCB (ATC with beta-adrenoceptor blockade) groups. Rats were injected intraperitoneally with propranolol or vehicle at baseline. Heart rate variability (HRV) and markers of inflammation, coagulation, and endothelial activation were measured, and Western blotting analysis of nuclear factor (NF)-κB was done after shock. Separate ATCC and ATCB groups were observed to compare overall mortality.

RESULTS

HRV showed enhanced sympathetic tone in the ATCC group, which was reversed by propranolol. Propranolol attenuated the induction of pro-inflammatory cytokines TNF-α and IL-6, as well as fibrinolysis markers plasmin antiplasmin complex and tissue-type plasminogen activator. The increased serum syndecan-1 and soluble thrombomodulin were inhibited by propranolol, and the NF-κB expression was also decreased by propranolol pretreatment. But propranolol did not alter overall mortality in rats with ATC after shock.

CONCLUSIONS

Beta-adrenoceptor blockade can alleviate sympathetic hyperactivity and exert anti-inflammatory, anti-fibrinolysis, and endothelial protective effects, confirming its pivotal role in the pathogenesis of ATC. Its mechanism in ATC should be explored further.

Curcumin Stimulates the Antioxidant Mechanisms in Mouse Skin Exposed to Fractionated γ-Irradiation

Fractionated irradiation is one of the important radiotherapy regimens to treat different types of neoplasia. Despite of the immense therapeutic gains accrued by delivering fractionated irradiation to tumors, the radiation burden on skin increases significantly. Low doses of irradiation to skin adversely affect its molecular and metabolic status. The use of antioxidant/s may help to alleviate the radiation-induced changes in the skin and allow delivering a higher dose of radiation to attain better therapeutic gains. Curcumin is an antioxidant and a free radical scavenging dietary supplement, commonly used as a flavoring agent in curries. Therefore, the effect of 100 mg/kg body weight curcumin was studied on the antioxidant status of mice skin exposed to a total dose of 10, 20 and 40 Gy γ-radiation below the rib cage delivered as a single fraction of 2 Gy per day for 5, 10 or 20 days. Skin biopsies from both the curcumin treated or untreated irradiated groups were collected for the biochemical estimations at various post-irradiation times. The irradiation of animals caused a dose dependent decline in the glutathione concentration, glutathione peroxidase, and superoxide dismutase activities and increased the lipid peroxidation in the irradiated skin. Curcumin treatment before irradiation resulted in a significant rise in the glutathione concentration and activities of both the glutathione peroxidase and superoxide dismutase enzymes in mouse skin, whereas lipid peroxidation declined significantly. The present study indicates that curcumin treatment increased the antioxidant status of mouse exposed to different doses of fractionated γ-radiation.

Curcumin ameliorates cognitive deficits heavy ion irradiation-induced learning and memory deficits through enhancing of Nrf2 antioxidant signaling pathways

Oxidative stress is one of the major mechanisms implicated in carbon ion irradiation. Curcumin is a natural phenolic compound with impressive antioxidant properties. What's more, curcumin is recently proved to exert its effects partly radioprotection. In vivo, we investigated the protective effects of curcumin against (12)C(6+)radiation-induced cerebral injury. Our results showed that 4Gy heavy ion radiation-induced spatial strategy and memory decline and reduction of brain superoxide dismutase (SOD) activity levels were all consistently improved by curcumin, and the augmentation of cerebral malonaldehyde (MDA) was lowered by curcumin. Furthermore, both the cerebral cells nuclear erythroid 2-related factor 2 (Nrf2) protein and three typically recognized Nrf2 downstream genes, NAD(P)H quinine oxidoreductase 1 (NQO1), heme oxygenase-1 (HO-1), and γ-glutamyl cysteine synthetase (γ-GCS) were consistently up-regulated in curcumin-pretreated mice. Our study confirmed the antagonistic roles of curcumin to counteract radiation-induced cerebral injury in vivo and suggested that the potent Nrf2 activation capability might be valuable for the protective effects of curcumin against radiation. This provides a potential useful radioprotection dietary component for human populations.

Compared effects of inhibition and exogenous administration of hydrogen sulphide in ischaemia-reperfusion injury

Introduction

Haemorrhagic shock is associated with an inflammatory response consecutive to ischaemia-reperfusion (I/R) that leads to cardiovascular failure and organ injury. The role of and the timing of administration of hydrogen sulphide (H₂S) remain uncertain. Vascular effects of H₂S are mainly mediated through K⁺_ATP-channel activation. Herein, we compared the effects of D,L-propargylglycine (PAG), an inhibitor of H₂S production, as well as sodium hydrosulphide (NaHS), an H₂S donor, on haemodynamics, vascular reactivity and cellular pathways in a rat model of I/R. We also compared the haemodynamic effects of NaHS administered before and 10 minutes after reperfusion.

Methods

Mechanically ventilated and instrumented rats were bled during 60 minutes in order to maintain mean arterial pressure at 40 ± 2 mmHg. Ten minutes prior to retransfusion, rats randomly received either an intravenous bolus of NaHS (0.2 mg/kg) or vehicle (0.9% NaCl) or PAG (50 mg/kg). PNU, a pore-forming receptor inhibitor of K⁺_ATP channels, was used to assess the role of K⁺_ATP channels.

Results

Shock and I/R induced a decrease in mean arterial pressure, lactic acidosis and ex vivo vascular hyporeactivity, which were attenuated by NaHS administered before reperfusion and PNU but not by PAG and NaHS administered 10 minutes after reperfusion. NaHS also prevented aortic inducible nitric oxide synthase expression and nitric oxide production while increasing Akt and endothelial nitric oxide synthase phosphorylation. NaHS reduced JNK activity and p-P38/P38 activation, suggesting a decrease in endothelial cell activation without variation in ERK phosphorylation. PNU + NaHS increased mean arterial pressure when compared with NaHS or PNU alone, suggesting a dual effect of NaHS on vascular reactivity.

Conclusion

NaHS when given before reperfusion protects against the effects of haemorrhage-induced I/R by acting primarily through a decrease in both proinflammatory cytokines and inducible nitric oxide synthase expression and an upregulation of the Akt/endothelial nitric oxide synthase pathway.

Keywords: hydrogen sulphide, inflammation mediators, therapeutic use, shock, hemorrhagic/drug therapy, haemodynamics/drug effects

Telmisartan protects against microvascular dysfunction during myocardial ischemia/reperfusion injury by activation of peroxisome proliferator-activated receptor γ

Background

We investigated the potential of telmisartan to improve microvascular dysfunction induced by myocardial ischemia/reperfusion (I/R) injury by activating the peroxisome proliferator-activated receptor gamma (PPARG) pathway.

Methods

Forty-eight male rabbits were randomly allocated into sham-operated, I/R, GW9662, telmisartan, telmisartan–GW9662, or candesartan groups. Rabbits were anesthetized, and the left anterior descending coronary artery (LAD) was ligated for 60 minutes. Following reperfusion for 6 hours, angiotensin II content of the heart was determined using radioimmunoassay. Myocardial neutrophil accumulation and microvessel cross-sectional area were examined histologically. Myocardial capillaries were examined with transmission electron microscopy. Intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) in the myocardium were measured using enzyme-linked immunosorbent assay. Western blot was utilized for investigating the expression of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) and PPARG.

Results

Angiotensin II concentration was significantly increased in all treatment groups compared with the sham-operated group (P < 0.05, all). Accumulation of polymorphonuclear neutrophils was significantly lower, while microvessel cross-sectional area was significantly higher in the telmisartan, telmisartan-GW9662, and candesartan groups compared with the I/R group (P < 0.05). ICAM-1 and VCAM-1 levels were also significantly lower, and correlated with lower NF-κB expression in these groups. The effects were the most significant in the telmisartan group compared with the telmisartan–GW9662 and candesartan groups. Telmisartan significantly increased PPARG protein expression compared with all other groups (P < 0.05, all).

Conclusions

Except for the typical effects of angiotensin II-receptor blocker, telmisartan improved microvascular dysfunction during myocardial I/R injury via the PPARG pathway.

High-lipid enteral nutrition could partially mitigate inflammation but not lung injury in hemorrhagic shock rats

BACKGROUND

Loss of gut barrier function is crucial in mediating lung injury induced by hemorrhagic shock/resuscitation (HS). High-lipid enteral nutrition (HL) can preserve gut barrier function. We hypothesized that HL could also mitigate HS-induced lung injury.

MATERIALS AND METHODS

Forty-eight adult male rats were randomly assigned to one of four experimental groups: HS; HS-HL; Sham; Sham-HL. HS was induced by blood drawing and mean blood pressure was maintained at 40-45 mmHg for 120 min followed by resuscitation with re-infusion of exsanguinated blood/saline mixtures. HL gavage was performed at 45 min before blood drawing and at the end of resuscitation.

RESULTS

Intestinal permeability of the HS group was significantly higher than that of the Sham group (P < 0.001). Pulmonary concentrations of malondialdehyde (lipid peroxidation) and inflammatory molecules, including prostaglandin E2, tumor necrosis factor-α, interleukin-6, and macrophage inflammatory protein-2, of the HS group were significantly higher than those of the Sham group. Histologic analyses, including histopathology, wet/dry weight ratio, and neutrophil infiltration revealed moderate lung injury in the HS group. In contrast, intestinal permeability (P < 0.001) and pulmonary concentrations of tumor necrosis factor-α and macrophage inflammatory protein-2 (P = 0.021 and 0.01) of the HS-HL group were significantly lower than those of the HS group. However, pulmonary concentrations of malondialdehyde, prostaglandin E2, and interleukin-6 of the HS-HL and HS groups were comparable. Moreover, histologic analyses also revealed moderate lung injury in the HS-HL group.

CONCLUSIONS

High-lipid enteral nutrition significantly mitigated gut barrier loss and partially mitigated lung inflammation but not oxidation and lung injury in hemorrhagic shock/resuscitation rats.

Injury-induced insulin resistance in adipose tissue

Hyperglycemia and insulin resistance are common findings in critical illness. Patients in the surgical ICU are frequently treated for this 'critical illness diabetes' with intensive insulin therapy, resulting in a substantial reduction in morbidity and mortality. Adipose tissue is an important insulin target tissue, but it is not known whether adipose tissue is affected by critical illness diabetes. In the present study, a rodent model of critical illness diabetes was used to determine whether adipose tissue becomes acutely insulin resistant and how insulin signaling pathways are being affected. There was a reduction in insulin-induced phosphorylation of IR, IRS-1, Akt and GSK-3β. Since insulin resistance occurs rapidly in adipose tissue, but before the insulin resistance in skeletal muscle, it may play a role in the initial development of critical illness diabetes.

Antioxidant strategies in neurocritical care

An increase in oxidative stress and overproduction of oxidizing reactive species plays an important role in the pathophysiology of several conditions encountered in the neurocritical care setting including: ischemic and hemorrhagic strokes, traumatic brain injury, acute respiratory distress syndrome, sepsis, and organ failure. The presence of oxidative stress in these conditions is supported by a large body of pre-clinical and clinical studies, and provides a rationale to support a potential therapeutic role for antioxidants. The purpose of this article is to briefly review the basic mechanisms and molecular biology of oxidative stress, summarize its role in critically ill neurological patients, and review available data regarding the potential role of antioxidant strategies in neurocritical care and future directions.

Rons formation under restrictive reperfusion does not affect organ dysfunction early after hemorrhage and trauma

Reactive oxygen species have been implicated in the pathophysiology of early reperfusion. We aimed to determine 1) reactive oxygen and nitrogen species (RONS) formation in organs of rats and 2) its pathophysiological relevance during a phase of restrictive reperfusion after hemorrhagic/traumatic shock (HTS). Fifty-seven male Sprague-Dawley rats were subjected to a clinically relevant HTS model, featuring laparotomy, bleeding, and a phase of restrictive reperfusion. The RONS scavenger 1-hydroxy-3-carboxy-2,2,5,5-tetramethyl-pyrrolidine hydrochloride (continuous i.v. infusion) and electron paramagnetic resonance spectroscopy were applied for RONS (primarily superoxide and peroxynitrite) detection. Compared with sham-operated animals, the organ-specific distribution of RONS changed during restrictive reperfusion after HTS. Reactive oxygen and nitrogen species formation increased during restrictive reperfusion in red blood cells and ileum only but decreased in the kidney and remained unchanged in other organs. Hemorrhagic traumatic shock followed by restrictive reperfusion resulted in metabolic acidosis, dysfunction of liver and kidney, and increased oxidative burst capacity in circulating cells. Plasma RONS correlated with shock severity and organ dysfunction. However, RONS scavenging neither affected organ dysfunction nor oxidative burst capacity nor myeloperoxidase activity in lung when compared with the shock controls. In summary, a phase of restrictive reperfusion does not increase RONS formation in most organs except in intestine and red blood cells. Moreover, scavenging of RONS does not affect the early organ dysfunction manifested at the end of a phase of restrictive reperfusion.

Prostaglandin F2α (PGF2α) stimulates PTGS2 expression and PGF2α synthesis through NFKB activation via reactive oxygen species in the corpus luteum of pseudopregnant rats

This study was undertaken to investigate how prostaglandin F(2α) (PGF(2α)) increases PGF(2α) synthesis and PTGS2 expression in the corpus luteum of pseudopregnant rats. We further investigated the molecular mechanism by which PGF(2α) stimulates PTGS2 expression. PGF(2α) (3 mg/kg) or phosphate buffer as a control was injected s.c. on day 7 of pseudopregnancy. Ptgs2 mRNA expression and PGF(2α) concentrations in the corpus luteum were measured at 2, 6, and 24 h after PGF(2α) injection. PGF(2α) significantly increased Ptgs2 mRNA expression at 2 h and luteal PGF(2α) concentrations at 24 h. PGF(2α) significantly decreased serum progesterone levels at all of the times studied. Simultaneous administration of a selective PTGS2 inhibitor (NS-398, 10 mg/kg) completely abolished the increase in luteal PGF(2α) concentrations induced by PGF(2α). PGF(2α) increased NFKB p65 protein expression in the nucleus of luteal cells 30 min after PGF(2α) injection, and electrophoretic mobility shift assay revealed that PGF(2α) increased binding activities of NFKB to the NFKB consensus sequence of the Ptgs2 gene promoter. Simultaneous administration of both superoxide dismutase and catalase to scavenge reactive oxygen species (ROS) inhibited the increases of nuclear NFKB p65 protein expression, lipid peroxide levels, and Ptgs2 mRNA expression induced by PGF(2α). In conclusion, PGF(2α) stimulates Ptgs2 mRNA expression and PGF(2α) synthesis through NFKB activation via ROS in the corpus luteum of pseudopregnant rats.

Valsartan preconditioning protects against myocardial ischemia-reperfusion injury through TLR4/NF-kappaB signaling pathway

Toll-like receptor 4 (TLR4) activation has been implicated in the pathogenesis of myocardial ischemia/reperfusion (I/R) injury. The activated TLR4 is capable of activating a variety of proinflammatory mediators, such as tumor necrosis factor-a (TNF-a) and interleukin-6 (IL-6). Valsartan as a kind of Angiotensin II type 1 receptor blockers is gradually used for the treatment of ischemic heart disease depending on its anti-inflammation function. Therefore, we hypothesized that valsartan protects against myocardial I/R injury by suppressing TLR4 activation. We constructed the rat model of myocardial I/R injury. The rats were pretreated with valsartan for 2 weeks, and then subjected to 30 min ischemia and 2 h reperfusion. TLR4 and Nuclear factor kappa-B (NF-kappaB) levels were detected by quantitative real-time PCR and western blot. In order to evaluate myocardial damage, the myocardial infarct size, histopathologic changes, and the release of myocardial enzymes, proinflammation cytokines and Angiotensin II were analyzed by triphenyl tetrazolium chloride (TTC) staining, light microscopy, and enzyme-linked immunosorbent assay (ELISA), respectively. Valsartan preconditioning inhibited TLR4 and NF-kappaB expressions concomitant with an improvement in myocardial injury, such as smaller infarct size, fewer release of myocardial enzymes, and proinflammation mediators. These findings suggest that valsartan plays a pivotal role in the protective effects on myocardial I/R injury. This protection mechanism is possibly due to its anti-inflammation function via TLR4/NF-kappaB signaling pathway.

Effect of toluene on erythrocyte membrane stability under in vivo and in vitro conditions with assessment of oxidant/antioxidant status

Toluene, an organic solvent used widely in the industry, is highly lipophilic and accumulates in the cell membrane impeding transport through it. Its metabolites cause oxygen radical formation that react with unsaturated fatty acids and proteins in erythrocytes leading to lipid peroxidation and protein breakdown. In this study, we aimed to investigate the membrane stabilizing and the oxidative stress-inducing effects of toluene in human erythrocytes. Measurements of osmotic fragility, mean corpuscular volume (MCV), oxidative stress parameters and antioxidant enzyme activities were performed simultaneously both in individuals exposed to toluene professionally (in vivo) and human erythrocytes treated with toluene (in vitro). To measure osmotic fragility, erythrocytes were placed in NaCl solutions at various concentrations (0.1% [blank], 0.38%, 0.40%, 0.42%, 0.44%, 0.46%, 0.48% and 1% [stock]). Percentage of haemolysis in each solution was calculated with respect to the 100% haemolysis in the blank solution. The erythrocyte packs prepared at the day of the above-mentioned measurements were kept at -80 degrees C until the time for determination of malonyldialdehyde and protein carbonyl levels, and catalase (CAT) and glutathione peroxidase activities as indicators of oxidative stress. Toluene increased oxidative stress parameters significantly both in vivo and in vitro; it also caused a significant decrease in the activities of antioxidant enzymes. Osmotic fragility was altered only in the case of in vitro exposure. In conclusion, toluene exposure resulted in increased lipid peroxidation and protein damage both in vivo and in vitro. Although, it is natural to expect increased osmotic fragility due to oxidative properties of toluene, its membrane-stabilizing effect overcame the oxidative properties leading to decreased osmotic fragility or preventing its deterioration in vitro and in vivo toluene exposures, respectively, in the present study.

The level of hypotension during hemorrhagic shock is a major determinant of the post-resuscitation systemic inflammatory response: an experimental study

Background

To evaluate whether the level of hypotension during hemorrhagic shock may influence the oxidative and inflammatory responses developed during post-ischemic resuscitation.

Methods

Fifteen rabbits were equally allocated into three groups: sham-operated (group sham); bled within 30 minutes to mean arterial pressure (MAP) of 40 mmHg (group shock-40); bled within 30 minutes to MAP of 30 mmHg (group shock-30). Shock was maintained for 60 min. Resuscitation was performed by reinfusing shed blood with two volumes of Ringer's lactate and blood was sampled for estimation of serum levels aminotransferases, creatinine, TNF-α, IL-1β, IL-6, malondialdehyde (MDA) and total antioxidant status (TAS) and for the determination of oxidative burst of polymorhonuclears (PMNs) and mononuclear cells (MCs).

Results

Serum AST of group shock-30 was higher than that of group shock-40 at 60 and 120 minutes after start of resuscitation; serum creatinine of group shock-30 was higher than group shock-40 at 120 minutes. Measured cytokines, MDA and cellular oxidative burst of groups, shock-40 and shock-30 were higher than group sham within the first 60 minutes after start of resuscitation. Serum concentrations of IL-1β, IL-6 and TNF-α of group shock-30 were higher than group shock-40 at 120 minutes (p < 0.05). No differences were found between two groups regarding serum MDA and TAS and oxidative burst on PMNs and MCs but both groups were different to group sham.

Conclusion

The level of hypotension is a major determinant of the severity of hepatic and renal dysfunction and of the inflammatory response arising during post-ischemic hemorrhagic shock resuscitation. These findings deserve further evaluation in the clinical setting.

Superoxide dismutase activity and malondialdehyde level in plasma and morphological evaluation of acute severe hemorrhagic shock in rats

OBJECTIVES

The aim of the study was to investigate the changes of the activity of superoxide dismutase (SOD) and the level of malondialdehyde (MDA) in plasma and organ damage during the acute severe hemorrhagic shock (ASHS), as well as to analyze their relationship.

METHODS

Twenty male Wistar rats (230-270 g) were randomly divided into sham hemorrhage shock (SHS) group and ASHS group. Acute severe hemorrhagic shock rats were induced by drawing blood through a femoral arterial catheter for 15 minutes with the final mean arterial blood pressure decreased to 35 to 40 mm Hg. The animals were killed after the mean arterial blood pressure was maintained at this level for 1 hour. The activity of SOD and the level of MDA in plasma were measured, and pathologic changes of the major organs (heart, liver, spleen, lung, kidney, and brain) were observed by microscopy.

RESULTS

The SOD activities and MDA levels in the ASHS group both increased continuously during the whole experiment. The SOD activities and MDA levels in plasma were not significantly different between the prehemorrhagic stage of ASHS and that of SHS (P > .05). The SOD activities and MDA levels were significantly higher in the ASHS initial stage than in the prehemorrhagic stage (P < .01). Compared with the ASHS initial stage, there was a significant (P < .01) increase in SOD activities and MDA levels in the ASHS end stage. Severe microscopic injuries appeared in the major organs (heart, liver, spleen, lung, kidney, and brain) of ASHS rats.

CONCLUSION

The changes of the activity of SOD and the level of MDA in ASHS may have a positive correlation.

Trans-sodium crocetinate and hemorrhagic shock

Trans-sodium crocetinate (TSC) has been found to alleviate the symptoms of hemorrhagic shock in that, after the drug is given to hemorrhaged rats, blood pressure rises, elevated lactate levels are reduced, cellular damage in the liver and kidney is less, and survival is increased. The mechanism of action proposed for TSC is that it increases the diffusion of oxygen through blood plasma and into the tissue. The study reported here explores another proposed mechanism, the scavenging of free radicals. It is shown that TSC does scavenge radicals and may be more efficient than other free-radical scavengers. However, this may not be the mechanism of action for TSC during hemorrhagic shock. Not only are the TSC concentrations needed for radical scavenging greater than those which provide beneficial effects in hemorrhagic shock, but it is also shown that another radical scavenger, trolox, has no effect on oxygen consumption during shock. Trans-sodium crocetinate clearly holds promise as a useful treatment of hemorrhagic shock. Pharmacokinetics data are presented for different modes of administration. Initial studies suggest that instillation of TSC into the trachea or intramuscular injection may provide useful alternative treatment routes.

Small volume resuscitation with tempol is detrimental during uncontrolled hemorrhagic shock in rats

BACKGROUND

In a previous study, titration of a hypertonic saline (HTS) solution during severe uncontrolled hemorrhagic shock (UHS) failed to reduce mortality. In a separate study, a novel antioxidant, polynitroxylated albumin (PNA) plus tempol (4-hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl), infused during shock increased long-term survival. We hypothesized that combining potent antioxidants with a hypertonic solution during UHS would preserve the logistical advantage of small volume resuscitation and improve survival.

METHODS

An UHS outcome model in rats was used. UHS phase I (90 min) included blood withdrawal of 30 ml/kg over 15 min, followed by tail amputation for uncontrolled bleeding. At 20 min, rats were randomized to four groups (n=10 each) for hypotensive resuscitation from 20 to 90 min (mean arterial pressure [MAP] > or = 40 mmHg): HTS/starch group received 7.2% NaCl/10% hydroxyethyl starch; HTS/albumin group received 7.5% NaCl/20% albumin; HTS/PNA group received 7.5% NaCl/20% PNA; HTS/albumin+tempol group received 7.5% NaCl/20% albumin plus tempol. Resuscitation phase II (180 min) included hemostasis, return of shed blood and administration of fluids to restore MAP > or = 80 mmHg. Observation phase III was to 72 h.

RESULTS

The total amount of fluid required to maintain hypotensive MAP during HS was low and did not differ between groups (range: 3.4+/-1.9 to 5.3+/-2.5 ml/kg). The rate of fluid administration required was higher in the HTS/albumin+tempol group compared to all other groups (p=0.006). Additional uncontrolled blood loss was highest in the HTS/PNA group (16.2+/-5.7 ml/kg [p=0.01] versus 10.4+/-7.9 ml/kg in the HTS/starch group, 7.7+/-5.2 ml/kg in the HTS/albumin group and 8.2+/-7.1 ml/kg in the HTS/albumin+tempol group). MAP after start of resuscitation in phase I was lower in the HTS/albumin+tempol group than the HTS/albumin or HTS/PNA groups (p<0.01). This group was also less tachycardic. Long-term survival was low in all groups (2 of 10 after HTS/starch and 1 of 10 after HTS/albumin, 3 of 10 after HTS/PNA, 1 of 10 after HTS/albumin+tempol). Median survival time was shortest in the HTS/albumin+tempol group (72 min [CI 34-190]) compared to all other groups (p=0.01).

CONCLUSIONS

Despite its benefits in other model systems, free tempol is potentially hazardous when combined with hypertonic fluids. PNA abrogates these deleterious effects on acute mortality but may lead to increased blood loss in the setting of UHS.

Vitamin E and NF‐κB Activation: A Review

Nuclear factor (NF-kappaB)(1) is a eukaryotic transcription factor that may be activated by oxidative stress. Because of this hypothesis, the effect of vitamin E on NF-kappaB activation has been examined in many studies, using both in vivo and in vitro models. Most of these studies have observed that vitamin E inhibits the activation of NF-kappaB, with the greatest inhibition seen with the succinate form. Vitamin E may be inhibiting NF-kappaB by reducing oxidative stress or through one of its nonantioxidant functions; this is not clear at the present time. It also is not known if the inhibition of NF-kappaB is necessary for any of vitamin E's effects on gene expression and the resulting physiological effects.

The role of RAGE in the pathogenesis of intestinal barrier dysfunction after hemorrhagic shock

The receptor for advanced glycation end products (RAGE) has been implicated in the pathogenesis of numerous conditions associated with excessive inflammation. To determine whether RAGE-dependent signaling is important in the development of intestinal barrier dysfunction after hemorrhagic shock and resuscitation (HS/R), C57Bl/6, rage(-/-), or congenic rage(+/+) mice were subjected to HS/R (mean arterial pressure of 25 mmHg for 3 h) or a sham procedure. Twenty-four hours later, bacterial translocation to mesenteric lymph nodes and ileal mucosal permeability to FITC-labeled dextran were assessed. Additionally, samples of ileum were obtained for immunofluorescence microscopy, and plasma was collected for measuring IL-6 and IL-10 levels. HS/R in C57Bl/6 mice was associated with increased bacterial translocation, ileal mucosal hyperpermeability, and high circulating levels of IL-6. All of these effects were prevented when C57Bl/6 mice were treated with recombinant human soluble RAGE (sRAGE; the extracellular ligand-binding domain of RAGE). HS/R induced bacterial translocation, ileal mucosal hyperpermeability, and high plasma IL-6 levels in rage(+/+) but not rage(-/-) mice. Circulating IL-10 levels were higher in rage(-/-) compared with rage(+/+) mice. These results suggest that activation of RAGE-dependent signaling is a key factor leading to gut mucosal barrier dysfunction after HS/R.

Perfluorocarbons decrease Chlamydophila pneumoniae-mediated inflammatory responses of rat type II pneumocytes in vitro

Chlamydophila pneumoniae alter the expression of Toll-like receptor (TLR) 4 in alveolar type II (ATII)-cells. Subsequently nuclear factor kappaB (NF-kappaB) is activated and tumor necrosis factor-alpha (TNF-alpha) and macrophage inflammatory protein 2 (MIP-2) are produced. Perfluorocarbons (PFC) are beneficial in animals with bacterial pneumonia and reduce production of TNF-alpha. Using isolated ATII-cells, it was studied whether PFC prevent C. pneumoniae-induced TNF-alpha and MIP-2 release and what the underlying pathway is. PF5080 preincubation prevented C. pneumoniae-induced secretion of TNF-alpha (43 +/- 10 versus 661 +/- 41 pg/mL) and MIP-2 (573 +/- 41 versus 4786 +/- 502 pg/mL). The C. pneumoniae-induced 2.2-fold increase of TNF-alpha Receptor 1 expression was reduced by PF5080. C. pneumoniae reduced cytoplasmatic IkappaBalpha (3.7 +/- 0.3 versus 14 +/- 1) and increased NF-kappaB p65 (31 +/- 7.5 versus 3.6 +/- 1.1) compared with control. PF5080 prevented NF-kappaB activation. TLR4 expression was 1.5-fold higher after C. pneumoniae incubation, but remained at control levels after PF5080 pretreatment. After 24 h of C. pneumoniae incubation, in 88 +/- 6% of cells bacteria were found in the perinuclear region and in 50% of these cells bacteria adhered to cellular surface. After PF5080 preincubation, C. pneumoniae were in 32 +/- 4% attached to and in 5 +/- 1% internalized in ATII-cells. Since PF5080 was found in ATII-cell membranes, PF5080 effect could be explained by an alteration of the cellular membrane, preventing activation of the inflammatory cascade.

Activation of the cholinergic anti-inflammatory pathway reduces NF-kappab activation, blunts TNF-alpha production, and protects againts splanchic artery occlusion shock

The cholinergic anti-inflammatory pathway has not yet been studied in splanchnic artery occlusion (SAO) shock. We investigated whether electrical stimulation (STIM) of efferent vagus nerves suppresses the inflammatory cascade in SAO shock. Animals were subjected to clamping of the splanchnic arteries for 45 min, followed by reperfusion. This surgical procedure resulted in an irreversible state of shock (SAO shock). Sham-operated animals were used as controls. Two minutes before the start of reperfusion, rats were subjected to bilateral cervical vagotomy (VGX) or sham surgical procedures. Application of constant voltage pulses to the caudal vagus ends (STIM: 5 V, 2 ms, 6 Hz for 15 min, 5 min after the beginning of reperfusion) increased survival rate (VGX + SAO + Sham STIM = 0% at 4 h of reperfusion; VGX + SAO + STIM = 90% at 4 h of reperfusion), reverted the marked hypotension, inhibited IkappaBalpha liver loss, blunted the augmented nuclear factor-kappaB activity, decreased hepatic tumor necrosis factor (TNF)-alpha mRNA (VGX + SAO + Sham STIM = 1.0 +/- 1.9 TNF-alpha/glyceraldehyde-3-phosphate dehydrogenase ratio; VGX + SAO + STIM = 0.3 +/- 0.2 TNF-alpha/glyceraldehyde-3-phosphate dehydrogenase ratio), reduced plasma TNF-alpha (VGX + SAO + Sham STIM = 118 +/- 19 pg/mL; VGX + SAO + STIM = 39 +/- 8 pg/mL), ameliorated leukopenia, and decreased leukocyte accumulation, as revealed by means of myeloperoxidase activity in the ileum (VGX + SAO + Sham STIM = 7.9 +/- 1 U/g tissue; VGX + SAO + STIM = 3.1 +/- 0.7 U/g tissue) and in the lung (VGX + SAO + Sham STIM = 8.0 +/- 1.0 U/g tissue; VGX + SAO + STIM = 3.2 +/- 0.6 U/g tissue). Chlorisondamine, a nicotinic receptor antagonist, abated the effects of vagal stimulation. Our results show a parasympathetic inhibition of nuclear factor-kappaB and TNF-alpha in SAO shock.

Hydrocortisone increases the sensitivity to α1-adrenoceptor stimulation in humans following hemorrhagic shock*

OBJECTIVE

To assess the pressor response to phenylephrine infusion before and after hydrocortisone in severe trauma patients and to correlate this response with their adrenal reserve.

DESIGN

Prospective clinical study.

SETTING

Surgical intensive care unit in a university teaching hospital.

PATIENTS

Twenty-three young trauma patients (Injury Severity Score, 38 +/- 14) were studied at the end of the resuscitative period (27 +/- 15 hrs after trauma).

INTERVENTIONS

Total cortisol response to intravenous corticotropin bolus (250 microg) was obtained. Total cortisol response <9 microg/dL defined an impaired adrenal function and the patient was called a nonresponder. Twelve to 24 hrs following this stimulation, phenylephrine was infused in a stepwise manner to establish the phenylephrine-mean arterial pressure dose-response curve before and after intravenous hydrocortisone administration (50 mg). An Emax model was used to describe the curve; the influence of the group (responder/nonresponder), the sequence (before/after hydrocortisone), and three covariates (Injury Severity Score, shock, and interleukin-6) were thereafter tested.

MEASUREMENTS AND MAIN RESULTS

Forty-three percent of patients were nonresponders. Total cortisol response was not correlated with serum albumin concentration and was negatively correlated with the interleukin-6 concentration. A trend for a higher incidence of nonresponders (53% vs. 36%) and a lesser total cortisol response (7.9 +/- 5.1 vs. 12.5 +/- 5.1 microg/dL) was observed in the shock patients. A phenylephrine dose-response structure (E0, ED50, and Emax) was described without influence of the group and the sequence. However, hydrocortisone induced a 37% decrease in ED50 without change in Emax in the shock patients.

CONCLUSION

An acute administration of hydrocortisone increases the sensitivity to alpha1-adrenoceptor stimulation in fully resuscitated severe trauma patients following hemorrhagic shock. This effect is independent of the adrenal reserve of the patients and different from that previously reported in septic patients.

Inhibition of lipid peroxidation by IRFI 042, a vitamin E analogue, decreases monensin cardiotoxicity in chicks

Monensin, a well-known ionophore antibiotic, may cause severe damage in myocardial cells. We investigated whether IRFI 042, a new analogue of vitamin E, may block lipid peroxidation in myocardial cells and in turn protect against monensin toxicity. Monensin toxicity was induced by repeated daily administration of the ionophore antibiotic (150 mg/kg/day for 7 days). Sham animals received by oral gavages only a saline solution and were used as controls. All animals were randomized to receive concomitantly by oral gavages IRFI 042 (20 mg/kg) or its vehicle. The experiment lasted 8 days. Survival rate, heart lipid peroxidation, studied by means of thiobarbituric acid-reactive substances (TBARs) levels, cardiac expression of endothelial nitric oxide (e-NOS) and histological analysis of the heart were performed. Monensin administration caused a decrease in survival rate. Mortality appeared following the second monensin injection and at day 7 caused a survival rate of 20%. Thereafter, no further mortality was observed. IRFI 042 administration improved survival rate. Injection of the ionophore antibiotic resulted in a marked cardiac lipid peroxidation and in a significant reduction in cardiac e-NOS message and protein expression. IRFI 042 decreased heart TBARs levels (Monensin + vehicle = 6.5 +/- 0.8 nmol/mg; Monensin + IRFI 042 = 3.2 +/- 1.1 nmol/mg; P < 0.001) and increased e-NOS message and protein expression. Histological analysis showed that IRFI 042 improved myocardial cells damage and enhanced the depressed e-NOS expression in chick heart samples following monensin administration. Our data suggest that IRFI 042 is a promising drug to reduce monensin cardio-toxicity in chicks.

TSC for hemorrhagic shock: effects on cytokines and blood pressure

Previous studies have shown that administering trans-sodium crocetinate (TSC) as a treatment of hemorrhagic shock leads to increased whole-body oxygen consumption and survival as well as protection of the liver and kidney. It has been suggested that TSC increases oxygen delivery by increasing the diffusivity of oxygen through plasma. However, as with any novel mechanism of action, there are always questions about whether the results could also be ascribed to other, previously described mechanisms of action. This study was designed to look at some aspects of that by examining the effect of different TSC dosing regimens on the blood pressure and the production of cytokines after hemorrhage because both responses have been reported with compounds that act via other mechanisms. In a constant-pressure rat model of hemorrhagic shock, it was seen that a singe bolus injection of TSC results in an immediate but transient increase in the arterial blood pressure. This is similar to the effect reported previously for using 100% oxygen. It was also found that if the TSC injections were repeated periodically over an hour, a sustained increase in the blood pressure would occur. Because inflammatory cytokines have been implicated in mortality and tissue damage, it has been suggested that TSC may affect the production of cytokines. Thus, the effect of TSC on the production of TNF-alpha and IL-10 was also examined. The data show that treatment with TSC results in lower concentrations of TNF-alpha in the liver and spleen as well as lower concentrations of IL-10 in the spleen. Again, similar effects on other cytokines have been seen with 100% oxygen. These results support the hypothesis that the effects of TSC on hemorrhagic shock are mediated via an effect on oxygen.

Chlamydophila pneumoniae induces expression of toll-like receptor 4 and release of TNF-alpha and MIP-2 via an NF-kappaB pathway in rat type II pneumocytes

Background

The role of alveolar type II cells in the regulation of innate and adaptive immunity is unclear. Toll-like receptors (TLRs) have been implicated in host defense. The purpose of the present study was to investigate whether Chlamydophila pneumoniae (I) alters the expression of TLR2 and/orTLR4 in type II cells in a (II) Rho-GTPase- and (III) NF-κB-dependent pathway, subsequently (IV) leading to the production of (IV) pro-inflammatory TNF-α and MIP-2.

Methods

Isolated rat type II pneumocytes were incubated with C. pneumoniae after pre-treatment with calcium chelator BAPTA-AM, inhibitors of NF-κB (parthenolide, SN50) or with a specific inhibitor of the Rho-GTPase (mevastatin). TLR2 and TLR4 mRNA expressions were analyzed by PCR. Activation of TLR4, Rac1, RhoA protein and NF-κB was determined by Western blotting and confocal laser scan microscopy (CLSM) and TNF-α and MIP-2 release by ELISA.

Results

Type II cells constitutively expressed TLR4 and TLR2 mRNA. A prominent induction of TLR4 but not TLR2 mRNA was detected after 2 hours of incubation with C. pneumoniae. The TLR4 protein expression reached a peak at 30 min, began to decrease within 1–2 hours and peaked again at 3 hours. Incubation of cells with heat-inactivated bacteria (56°C for 30 min) significantly reduced the TLR4 expression. Treated bacteria with polymyxin B (2 μg/ml) did not alter TLR4 expression. C. pneumoniae-induced NF-κB activity was blocked by TLR4 blocking antibodies. TLR4 mRNA and protein expression were inhibited in the presence of BAPTA-AM, SN50 or parthenolide. TNF-α and MIP-2 release was increased in type II cells in response to C. pneumoniae, whereas BAPTA-AM, SN50 or parthenolide decreased the C. pneumoniae-induced TNF-α and MIP-2 release. Mevastatin inhibited C. pneumoniae-mediated Rac1, RhoA and TLR4 expression.

Conclusion

The TLR4 protein expression in rat type II cells is likely to be mediated by a heat-sensitive C. pneumoniae protein that induces a fast Ca²⁺-mediated NF-κB activity, necessary for maintenance of TLR4 expression and TNF-α and MIP-2 release through possibly Rac and Rho protein-dependent mechanism. These results indicate that type II pneumocytes play an important role in the innate pulmonary immune system and in inflammatory response mechanism of the alveolus.

Functional significance of inflammatory mediators in a murine model of resuscitated hemorrhagic shock

The mechanisms that underlie the development of myocardial dysfunction after resuscitated hemorrhagic shock (HS) are not known. Recent studies suggest that systemic activation of inflammatory mediators may contribute to cellular dysfunction and/or cell death in various organs, including the heart. However, the precise role that inflammatory mediators play in the heart in the setting of resuscitated HS is not known. Accordingly, the purpose of the present study was to use a well-defined murine model of resuscitated HS to characterize the functional significance of inflammatory mediators in the heart in vivo. Mice were subjected to sham operation or resuscitated HS. Left ventricular (LV) function was assessed by two-dimensional echocardiography 6 h after resuscitation. Myocardial TNF, IL-1β, and IL-6 proteins were measured 1 and 6 h after resuscitation. To determine the role of TNF in HS-induced LV dysfunction, mice were treated with a soluble TNF receptor antagonist (etanercept) before HS or at the time of resuscitation. LV fractional shortening was significantly depressed ( P < 0.05) in resuscitated HS mice (28 ± 1.5%) compared with sham controls (35.8 ± 1.0%). TNF and IL-1β levels were significantly increased ( P < 0.05) in resuscitated HS mice. Pretreatment with etanercept abrogated resuscitated HS-induced LV dysfunction, whereas treatment at the time of resuscitation significantly attenuated, but did not abrogate, LV dysfunction. Together, these data suggest that TNF plays a critical upstream role in resuscitated HS-induced LV dysfunction; however, once the deleterious consequences of reperfusion injury are initiated, TNF contributes to, but is not necessary for, the development of LV dysfunction.

Contact of Chlamydophila pneumoniae with type II cell triggers activation of calcium-mediated NF-κB pathway

Nuclear factor-kappa B (NF-kappa B) plays an important role in inflammation, proliferation and regulation of apoptosis. The purpose of the present study on type II cells was to investigate whether Chlamydophila pneumoniae contact induces (I) a Ca2+ release, that (II) disrupts F-actin/beta-tubulin cytoskeletal association with NF-kappa B/I kappa B alpha, leading to (III) a subsequent NF-kappa B activation. Incubation of rat type II pneumocytes with C. pneumoniae caused an intracellular calcium release within seconds. Confocal laser scanning microscopy (CLSM) revealed that bacterial contact with cell surface leads to a disappearance of the microvilli and disturbs the co-localization between F-actin and NF-kappa B (p65). Using semi-quantitative CLSM, we show that at 10-30 min I kappa B alpha was decreased and p65 or p50 was simultaneously translocated from cytoplasm to the nucleus, resulting in a 19-fold and 17-fold increase versus control cells. During this time no bacteria were internalized into type II cells. The pre-treatment of cells with BAPTA-AM inhibited C. pneumoniae-mediated calcium release. BAPTA-AM or SN50 prevented the C. pneumoniae-induced changes in F-actin cytoskeleton and inhibited NF-kappa B activation. Paclitaxel reduced C. pneumoniae-mediated changes of beta-tubulin cytoskeleton and activation of NF-kappa B. These results suggest that calcium-mediated cytoskeleton reorganization is involved in C. pneumoniae-induced NF-kappa B activation in type II cells.

N/A

N/A

Methionine-induced hyperhomocysteinemia promotes superoxide anion generation and NFkappaB activation in peritoneal macrophages of C57BL/6 mice

It is well documented that hyperhomocysteinemia (HHcy) is an independent risk factor for atherosclerosis. This study was designed to investigate whether some of the atherosclerotic effects ascribed to HHcy are mediated by oxidative stress and nuclear factor kappa B (NFkappaB) activation in peritoneal macrophages of C57BL/6 mice fed a high (2%) methionine/low (1 mg/kg) folate diet for 12 weeks. Plasma homocysteine concentrations in mice fed methionine averaged 49 mol/L after 12 weeks of feeding, five times higher than that of controls. HHcy induced by methionine feeding significantly elevated oxidative stress, as measured by superoxide anion radical level (P <.05) in peritoneal macrophages. Furthermore, NFkappaB binding activities of peritoneal macrophages were higher in the methionine group than in the control group. These results suggest that HHcy induced by methionine may intensify disturbances in peroxidation and inflammatory mediator activation in peritoneal macrophages, and is a possible mechanism of its atherogenic effects.

Raxofelast, a hydrophilic vitamin E-like antioxidant, reduces testicular ischemia-reperfusion injury

Testis torsion is a surgical emergency that lead to permanent gonad damage. The damage has been ascribed to mechanisms of ischemia-reperfusion similar to other tissues. The mechanisms involved are different, but the lipid peroxidation of plasma membrane, caused by reactive oxygen species (ROS), generated particularly during reperfusion, is one of the most accredited. In the present study, we aimed to evaluate the effects of raxofelast, a vitamin E-like antioxidant with potent action and no systemic toxicity, on lipid peroxidation and histopathology in both testes after unilateral testicular torsion and detorsion. Adult male Wistar rats were subjected to total occlusion (3 h) of the left testis followed by 4 hours of reperfusion (TI/R). Sham testicular ischemia-reperfusion rats (SHAM TI/R) were used as controls. The animals were then randomized to receive either vehicle (1 ml/kg/i.p. of a dimetylsulphoxide/NaCl 0.9% 1:10 v/v solution, injected either 15 min before detorsion and 15 min after detorsion) or raxofelast (20 mg/kg i.p. 15 min before detorsion and 15 min after detorsion). Conjugated dienes (CD) levels, an index of lipid peroxidation, and testis histopathology were evaluated. Testicular ischemia reperfusion (TI/R) in untreated rats produced high testicular levels of CD (3.6+/-0.3 DeltaABS/g protein on the left side and 2.5+/-0.2 DeltaABS/g protein on the right side). Furthermore, histological examination revealed marked damage to the testis interstitium with severe haemorrhage and edema. The administration of raxofelast lowered CD levels (2.8+/-0.2 DeltaABS/g protein on the left side and 1.9+/-0.1 DeltaABS/g protein in the right side) and significantly reduced histological damage. These data suggest that the hydrophilic vitamin E-like antioxidants are good candidates for designing a novel therapeutic strategy to halt the oxidative stress that follows acute testis torsion.

Modulation of IL-1 beta gene expression by lipid peroxidation inhibition after kainic acid-induced rat brain injury

Brain injury was induced by intraperitoneal administration of kainic acid (KA, 10 mg/kg). Animals were randomized to receive either IRFI 042 (20 mg/kg i.p.), a lipid peroxidation inhibitor, or its vehicle (NaCl 0.9% DMSO 10% 1 ml/kg i.p.) 30 min before KA administration. A first set of animals was sacrificed 6 h after KA injection to measure malondialdehyde (MDA) content, glutathione-reduced (GSH) levels and the mRNA for interleukin-1beta (IL-1beta) in the cortex and in the hippocampus. A second set of animals was sacrificed 48 h after KA administration for histological analysis. All animals were observed for monitoring the behavioral sequelae and for evaluating latency of convulsions. Sham brain injury rats were used as controls. Intraperitoneal administration of IRFI 042 significantly decreased brain MDA (cortex: KA + vehicle = 0.285 +/- 0.04 nmol/mg protein; KA + IRFI 042 = 0.156 +/- 0.02 nmol/mg protein, P < 0.005; hippocampus: KA + vehicle = 0.350 +/- 0.03 nmol/mg protein; KA + IRFI 042 = 0.17 +/- 0.04 nmol/mg protein, P < 0.005), prevented the brain loss of GSH in both cortex (KA + vehicle = 7.81 +/- 1 micromol/g protein; KA + IRFI 042 = 12.1 +/- 1 micromol/g protein; P < 0.005) and hippocampus (KA + vehicle = 5 +/- 0.8 micromol/g protein; KA + IRFI 042 = 9.4 +/- 1.8 micromol/g protein; P < 0.005), reduced both brain IL-1beta mRNA expression and oedema, and increased latency of convulsions. Histological analysis showed a reduction of cell damage in IRFI 042-treated samples. The present data indicate that lipid peroxidation inhibition reduces IL-1beta gene expression and protects against kainic acid-induced brain damage.

Attenuated cerulein-induced pancreatitis in nuclear factor-kappaB-deficient mice

Nuclear factor (NF)-kappaB plays a central role in acute pancreatitis. We studied cerulein (CER)-induced pancreatitis in NF-kappaB knockout (KO) mice. NF-kappaB KO mice and normal control littermate wild-type (WT) mice were given four hyperstimulating doses of cerulein every hour to elicit secreatagogue-induced pancreatitis. Malonildialdehyde activity, glutathione levels, myeloperoxidase activity, TNF-alpha, and NF-kappaB binding activity and its inhibitory protein IkappaBalpha were studied in the pancreas. Furthermore, we measured plasma lipase and amylase and the histological damage. KO mice had reduced malonildialdehyde levels (WT + CER = 4.083 +/- 0.95 micromol/g; KO + CER = 1.513 +/- 0.63 microol/g), decreased myeloperoxidase activity (WT + CER = 19.3 +/- 2.39 mU/g; KO + CER = 10.21 +/- 2.05 mU/g), increased glutathione levels (WT + CER 6.22 +/- 2.46 micromol/g; KO + CER = 15. 516 +/- 2.92 micromol/g), and reduced serum levels of amylase (WT + CER = 2519 +/- 656.9 U/L; KO + CER = 916 +/- 280.4 U/L) and lipase (WT + CER = 1420 +/- 170 U/L; KO + CER = 861 +/- 172. 3 U/L). KO mice showed reduced pancreatic NF-kappaB activation, decreased TNF-alpha tissue content, and reduced histologic alterations. Our data suggest that KO mice have an attenuated cerulein-induced pancreatitis and help to define the possible interaction between NF-kappaB activation and oxidative stress in this deleterious event.

Lipopolysaccharide induces anandamide synthesis in macrophages via CD14/MAPK/phosphoinositide 3-kinase/NF-kappaB independently of platelet-activating factor

Macrophage-derived endocannabinoids have been implicated in endotoxin (lipopolysaccharide (LPS))-induced hypotension, but the endocannabinoid involved and the mechanism of its regulation by LPS are unknown. In RAW264.7 mouse macrophages, LPS (10 ng/ml) increases anandamide (AEA) levels >10-fold via CD14-, NF-kappaB-, and p44/42-dependent, platelet-activating factor-independent activation of the AEA biosynthetic enzymes, N-acyltransferase and phospholipase D. LPS also induces the AEA-degrading enzyme fatty acid amidohydrolase (FAAH), and inhibition of FAAH activity potentiates, whereas actinomycin D or cycloheximide blocks the LPS-induced increase in AEA levels and N-acyltransferase and phospholipase D activities. In contrast, cellular levels of the endocannabinoid 2-arachidonoylglycerol (2-AG) are unaffected by LPS but increased by platelet-activating factor. LPS similarly induces AEA, but not 2-AG, in mouse peritoneal macrophages where basal AEA levels are higher, and the LPS-stimulated increase in AEA is potentiated in cells from FAAH-/- as compared with FAAH+/+ mice. Intravenous administration of 107 LPS-treated mouse macrophages to anesthetized rats elicits hypotension, which is much greater in response to FAAH-/- than FAAH+/+ cells and is susceptible to inhibition by SR141716, a cannabinoid CB1 receptor antagonist. We conclude that AEA and 2-AG synthesis are differentially regulated in macrophages, and AEA rather than 2-AG is a major contributor to LPS-induced hypotension.

Effect of hepatic NF-κB on ICAM-1 expression in rats with acute pancreatitis

AIM

To study the effect of hepatic NF-κB on ICAM-1 expression in rats with acute pancreatitis.

METHODS

Seventy-two Wistar rats were randomly divided into three groups: acute pancreatitis group (AP), acute pancreatitis treated with pyrrolidine dithiocarbamate(PDTC) group (APP) and sham operation group (SO). Hepatic NF-κB activities were determined with EMSA. The expression of hepatic ICAM-1 was detected with immunohistochemistry. Hepatic myeloperoxidase (MPO) and serum alanine aminotransferase (ALT) were measured.

RESULTS

Activities of NF-κB were significantly higher in AP and APP groups than that in SO group from 3 to 6 hours. The expressions of ICAM-1 were stronger in AP and APP groups than in SO group. The levels of hepatic MPO and serum ALT were also significantly higher in these two groups than in SO group. However, compared with AP group, the activities of NF-κB, the expression of ICAM-1 and the level of hepatic MPO and ALT significantly decreased in APP group.

CONCLUSION

Activation of hepatic NF-κB is involved in the liver injury by regulating ICAM-1 expression during pancreatitis.