Maintenance of lung myeloperoxidase activity in proestrus females after trauma-hemorrhage: upregulation of heme oxygenase-1

A preclinical systematic review and meta-analysis assessing the effect of biological sex in lipopolysaccharide-induced acute lung injury

It is unclear what effect biological sex has on outcomes of acute lung injury (ALI). Clinical studies are confounded by their observational design. We addressed this knowledge gap with a preclinical systematic review of ALI animal studies. We searched MEDLINE and Embase for studies of intratracheal/intranasal/aerosolized lipopolysaccharide administration (the most common ALI model) that reported sex-stratified data. Screening and data extraction were conducted in duplicate. Our primary outcome was histological tissue injury and secondary outcomes included alveolar-capillary barrier alterations and inflammatory markers. We used a random-effects inverse variance meta-analysis, expressing data as standardized mean difference (SMD) with 95% confidence intervals (CIs). Risk of bias was assessed using the Systematic Review Centre for Laboratory Animal Experimentation (SYRCLE) tool. We identified six studies involving 132 animals across 11 independent experiments. A total of 41 outcomes were extracted, with the direction of effect suggesting greater severity in males than females in 26/41 outcomes (63%). One study reported on lung histology and found that male mice exhibited greater injury than females (SMD: 1.61, 95% CI: 0.53-2.69). Meta-analysis demonstrated significantly elevated albumin levels (SMD: 2.17, 95% CI: 0.63-3.70) and total cell counts (SMD: 0.80, 95% CI: 0.27-1.33) in bronchoalveolar lavage fluid from male mice compared with female mice. Most studies had an "unclear risk of bias." Our findings suggest sex-related differences in ALI severity. However, these conclusions are drawn from a small number of animals and studies. Further research is required to address the fundamental issue of biological sex differences in LPS-induced ALI.

The impact of patient sex on survival after unintentional trauma in Korea: a retrospective, observational, case-control study

OBJECTIVE

This study aimed to describe the relationship between sex and survival in patients experiencing unintentional trauma.

METHODS

This retrospective, national population-based observational, case-control study involved a cohort of Korean trauma patients who were transferred to an emergency department by a Korean emergency medical service from January 1 to December 31, 2018. Propensity score matching was used. The primary outcome was survival until hospital discharge.

RESULTS

Of 25,743 patients with severe unintentional trauma, 17,771 were male and 7,972 were female. Prior to propensity score matching, there was no significant difference in survival among male and female patients (92.6% vs. 93.1%, P=0.105). After using propensity score matching to adjust for confounders, there was still no sex difference in survival (male, 93.6% vs. female, 93.1%; P=0.270).

CONCLUSION

Survival after severe trauma was not influenced by the sex of the patient. Further studies with patients of reproductive age and a larger study population are needed to analyze the effects of sex on survival in patients with trauma.

Gender differences in trauma, shock and sepsis

Despite efforts in prevention and intensive care, trauma and subsequent sepsis are still associated with a high mortality rate. Traumatic injury remains the main cause of death in people younger than 45 years and is thus a source of immense social and economic burden. In recent years, the knowledge concerning gender medicine has continuously increased. A number of studies have reported gender dimorphism in terms of response to trauma, shock and sepsis. However, the advantageous outcome following trauma-hemorrhage in females is not due only to sex. Rather, it is due to the prevailing hormonal milieu of the victim. In this respect, various experimental and clinical studies have demonstrated beneficial effects of estrogen for the central nervous system, the cardiopulmonary system, the liver, the kidneys, the immune system, and for the overall survival of the host. Nonetheless, there remains a gap between the bench and the bedside. This is most likely because clinical studies have not accounted for the estrus cycle. This review attempts to provide an overview of the current level of knowledge and highlights the most important organ systems responding to trauma, shock and sepsis. There continues to be a need for clinical studies on the prevailing hormonal milieu following trauma, shock and sepsis.

Nitric oxide-heat shock protein axis in menopausal hot flushes: neglected metabolic issues of chronic inflammatory diseases associated with deranged heat shock response

BACKGROUND

Although some unequivocal underlying mechanisms of menopausal hot flushes have been demonstrated in animal models, the paucity of similar approaches in humans impedes further mechanistic outcomes. Human studies might show some as yet unexpected physiological mechanisms of metabolic adaptation that permeate the phase of decreased oestrogen levels in both symptomatic and asymptomatic women. This is particularly relevant because both the severity and time span of hot flushes are associated with increased risk of chronic inflammatory disease. On the other hand, oestrogen induces the expression of heat shock proteins of the 70 kDa family (HSP70), which are anti-inflammatory and cytoprotective protein chaperones, whose expression is modulated by different types of physiologically stressful situations, including heat stress and exercise. Therefore, lower HSP70 expression secondary to oestrogen deficiency increases cardiovascular risk and predisposes the patient to senescence-associated secretory phenotype (SASP) that culminates in chronic inflammatory diseases, such as obesities, type 2 diabetes, neuromuscular and neurodegenerative diseases.

OBJECTIVE AND RATIONALE

This review focuses on HSP70 and its accompanying heat shock response (HSR), which is an anti-inflammatory and antisenescent pathway whose intracellular triggering is also oestrogen-dependent via nitric oxide (NO) production. The main goal of the manuscript was to show that the vasomotor symptoms that accompany hot flushes may be a disguised clue for important neuroendocrine alterations linking oestrogen deficiency to the anti-inflammatory HSR.

SEARCH METHODS

Results from our own group and recent evidence on hypothalamic control of central temperature guided a search on PubMed and Google Scholar websites.

OUTCOMES

Oestrogen elicits rapid production of the vasodilatory gas NO, a powerful activator of HSP70 expression. Whence, part of the protective effects of oestrogen over cardiovascular and neuroendocrine systems is tied to its capacity of inducing the NO-elicited HSR. The hypothalamic areas involved in thermoregulation (infundibular nucleus in humans and arcuate nucleus in other mammals) and whose neurons are known to have their function altered after long-term oestrogen ablation, particularly kisspeptin-neurokinin B-dynorphin neurons, (KNDy) are the same that drive neuroprotective expression of HSP70 and, in many cases, this response is via NO even in the absence of oestrogen. From thence, it is not illogical that hot flushes might be related to an evolutionary adaptation to re-equip the NO-HSP70 axis during the downfall of circulating oestrogen.

WIDER IMPLICATIONS

Understanding of HSR could shed light on yet uncovered mechanisms of menopause-associated diseases as well as on possible manipulation of HSR in menopausal women through physiological, pharmacological, nutraceutical and prebiotic interventions. Moreover, decreased HSR indices (that can be clinically determined with ease) in perimenopause could be of prognostic value in predicting the moment and appropriateness of starting a HRT.

The Role and Use of Estrogens Following Trauma

Several lines of evidence indicate that female sex is a protective factor in trauma and hemorrhage. In both clinical and experimental studies, proestrus females have been shown to have better chances of survival and reduced rates of posttraumatic sepsis. Estrogen receptors are expressed in a variety of tissues and exert genomic, as well as nongenomic effects. By improving cardiac, pulmonary, hepatic, and immune function, estrogens have been shown to prolong survival in animal models of hemorrhagic shock. Despite encouraging results from experimental studies, retrospective clinical studies have not clearly pointed to advantages of estrogens following trauma-hemorrhage, which may be due to insufficient study design. Therefore, this review aims to give an overview on the current evidence and emphasizes on the importance of further clinical investigation on estrogens following trauma.

XOR inhibition with febuxostat accelerates pulmonary endothelial barrier recovery and improves survival in lipopolysaccharide-induced murine sepsis

Sepsis is a leading cause of death among patients in the intensive care unit, resulting from multi-organ failure. Activity of xanthine oxidoreductase (XOR), a reactive oxygen species (ROS) producing enzyme, is known to be elevated in nonsurvivors of sepsis compared to survivors. We have previously demonstrated that XOR is critical for ventilator-induced lung injury. Using febuxostat, a novel nonpurine inhibitor of XOR, we sought to determine the role of XOR inhibition in a murine model of sepsis-induced lung injury and mortality. C57BL/6J mice were subjected to intravenous (IV) lipopolysaccharide (LPS) for various time points, and lungs were harvested for analyses. Subsets of mice were treated with febuxostat, pre or post LPS exposure, or vehicle. Separate groups of mice were followed up for mortality after LPS exposure. After 24 hr of IV LPS, mice exhibited an increase in XOR activity in lung tissue and a significant increase in pulmonary endothelial barrier disruption. Pretreatment of animals with febuxostat before exposure to LPS, or treatment 4 h after LPS, resulted in complete abrogation of XOR activity. Inhibition of XOR with febuxostat did not prevent LPS-induced pulmonary vascular permeability at 24 h, however, it accelerated recovery of the pulmonary endothelial barrier integrity in response to LPS exposure. Furthermore, treatment with febuxostat resulted in significant reduction in mortality. Inhibition of XOR with febuxostat accelerates recovery of the pulmonary endothelial barrier and prevents LPS-induced mortality, whether given before or after exposure to LPS.

Sex-based differences in outcomes after severe injury: an analysis of blunt trauma patients in China

BACKGROUND

Experimental research suggests that females have a higher survival rate after trauma, although this claim is controversial. This study sought to determine the role of sex on mortality among trauma patients in China.

METHODS

The study enrolled 1789 trauma patients who visited the Emergency Intensive Care Unit of the First Affiliated Hospital of Zhengzhou University during 2015 and 2016. A retrospective data analysis was performed to determine sex-based differences after blunt trauma. Patients were stratified by age and injury severity (using the Injury Severity Score). Multiple logistic regression was used to analyze the association between sex and post-injury complications and mortality.

RESULTS

Female trauma patients experienced a significantly lower risk of mortality than males (odds ratio, 0.931; 95% confidence interval, 0.883-0.982). This survival advantage of females was particularly notable in the 'younger than 45 years' age group. Sex-based differences were also found in the occurrence of life-threatening complications after trauma.

CONCLUSION

This study demonstrated that females are more likely to survival after severe blunt trauma and also have less inpatient complications than men, suggesting an important role for sex hormones after severe traumatic injury.

Anti-Inflammatory and Organ-Protective Effects of Resveratrol in Trauma-Hemorrhagic Injury

Resveratrol, a natural polyphenolic compound of grape and red wine, owns potential anti-inflammatory effects, which results in the reduction of cytokines overproduction, the inhibition of neutrophil activity, and the alteration of adhesion molecules expression. Resveratrol also possesses antioxidant, anti-coagulation and anti-aging properties, and it may control of cell cycle and apoptosis. Resveratrol has been shown to reduce organ damage following traumatic and shock-like states. Such protective phenomenon is reported to be implicated in a variety of intracellular signaling pathways including the activation of estrogen receptor, the regulation of the sirtuin 1/nuclear factor-kappa B and mitogen-activated protein kinases/hemeoxygenase-1 pathway, and the mediation of proinflammatory cytokines and reactive oxygen species formation and reaction. In the recent studies, resveratrol attenuates hepatocyte injury and improves cardiac contractility due to reduction of proinflammatory mediator expression and ameliorates hypoxia-induced liver and kidney mitochondrial dysfunction following trauma and hemorrhagic injuries. Moreover, through anti-inflammatory effects and antioxidant properties, the resveratrol is believed to protect organ function in trauma-hemorrhagic injury. In this review, the organ-protective and anti-inflammatory effects of resveratrol in trauma-hemorrhagic injury will be discussed.

Potential therapeutic targets for sepsis in women

INTRODUCTION

Gender is increasingly recognized as a key factor in trauma and sepsis. Multiple clinical and experimental studies on sepsis have shown a distinct advantage of females in the proestrus cycle to survive sepsis compared with age-matched males. In addition, estrogen treatment is beneficial in non-proestrus cycles and also in ovarectomized females. In this manuscript, the effects of gender and sex hormones in sepsis are summarized and potential gender-specific therapeutic strategies in women are evaluated.

AREAS COVERED

This review comprises current clinical studies on the effect of gender in sepsis and gives an overview on gender and sex hormone-related effects on immune cells and organ function. Based on clinical and experimental data, potential therapeutic targets are presented.

EXPERT OPINION

Estrogens and estrogen-receptor agonists have been extensively shown to be beneficial in the setting of sepsis. Clinical data, however, do not clearly support their therapeutic use. This discrepancy appears to be mainly due to insufficient study design in clinical trials conducted up to now. Therefore, improved study protocols with exact analysis of the patients' hormonal status are needed to clarify the role of gender and sex hormones in trauma and sepsis.

Plasminogen activator inhibitor-1 in cigarette smoke exposure and influenza A virus infection-induced lung injury

Parenchymal lung inflammation and airway and alveolar epithelial cell apoptosis are associated with cigarette smoke exposure (CSE), which contributes to chronic obstructive pulmonary disease (COPD). Epidemiological studies indicate that people exposed to chronic cigarette smoke with or without COPD are more susceptible to influenza A virus (IAV) infection. We found increased p53, PAI-1 and apoptosis in AECs, with accumulation of macrophages and neutrophils in the lungs of patients with COPD. In Wild-type (WT) mice with passive CSE (PCSE), p53 and PAI-1 expression and apoptosis were increased in AECs as was lung inflammation, while those lacking p53 or PAI-1 resisted AEC apoptosis and lung inflammation. Further, inhibition of p53-mediated induction of PAI-1 by treatment of WT mice with caveolin-1 scaffolding domain peptide (CSP) reduced PCSE-induced lung inflammation and reversed PCSE-induced suppression of eosinophil-associated RNase1 (EAR1). Competitive inhibition of the p53-PAI-1 mRNA interaction by expressing p53-binding 3’UTR sequences of PAI-1 mRNA likewise suppressed CS-induced PAI-1 and AEC apoptosis and restored EAR1 expression. Consistent with PCSE-induced lung injury, IAV infection increased p53, PAI-1 and apoptosis in AECs in association with pulmonary inflammation. Lung inflammation induced by PCSE was worsened by subsequent exposure to IAV. Mice lacking PAI-1 that were exposed to IAV showed minimal viral burden based on M2 antigen and hemagglutination analyses, whereas transgenic mice that overexpress PAI-1 without PCSE showed increased M2 antigen and inflammation after IAV infection. These observations indicate that increased PAI-1 expression promotes AEC apoptosis and exacerbates lung inflammation induced by IAV following PCSE.

Role of p38 MAPK pathway in 17β-estradiol-mediated attenuation of hemorrhagic shock-induced hepatic injury

Although 17β-estradiol (E2) treatment following hemorrhagic shock or ischemic reperfusion prevents organs from dysfunction and injury, the precise mechanism remains unknown. We hypothesize that the E2-mediated attenuation of liver injury following hemorrhagic shock and fluid resuscitation occurs via the p38 mitogen-activated protein kinase (MAPK)-dependent heme oxygenase (HO)-1 pathway. After a 5-cm midline laparotomy, male rats underwent hemorrhagic shock (mean blood pressure ∼40 mmHg for 90 min) followed by fluid resuscitation. At the onset of resuscitation, rats were treated with vehicle, E2 (1 mg/kg) alone, or E2 plus p38 MAPK inhibitor SB-203580 (2 mg/kg), HO-1 inhibitor chromium mesoporphyrin-IX chloride (2.5 mg/kg) or estrogen receptor antagonist ICI 182,780 (3 mg/kg). At 2 h after hemorrhagic shock and fluid resuscitation, the liver injury markers were significantly increased compared with sham-operated control. Hemorrhagic shock resulted in a significant decrease in p38 MAPK phosphorylation compared with the shams. Administration of E2 following hemorrhagic shock normalized liver p38 MAPK phosphorylation, further increased HO-1 expression, and reduced cleaved caspase-3 levels. Coadministration of SB-203580 abolished the E2-mediated attenuation of the shock-induced liver injury markers. In addition, administration of chromium mesoporphyrin-IX chloride or ICI 182,780 abolished E2-mediated increases in liver HO-1 expression or p38 MAPK activation following hemorrhagic shock. Our results collectively suggest that the salutary effects of E2 on hepatic injury following hemorrhagic shock and resuscitation are in part mediated through an estrogen-receptor-related p38 MAPK-dependent HO-1 upregulation.

Estrus cycle status defined by vaginal cytology does not correspond to fluctuations of circulating estrogens in female mice

Gender-oriented studies in shock, trauma, and/or sepsis require accurate monitoring of hormonal fluctuations as estrogens may influence various end points. Yet, monitoring is challenging in small laboratory animals: e.g., despite its subjectivity, vaginal smears are the major method for determination of estrus cycle phases in mice. Using female mice of different age, we aimed to (a) characterize general age-related changes in systemic estrogens and (b) examine the utility of determination of the estrus cycle by vaginal smears and/or impedance simultaneously comparing them with oscillation of systemic estrogens. In this study, 3-, 15-, and 20-month-old mice underwent vaginal smear and impedance examination each morning for 22 days. Ten hours after each morning checkup, feces were collected, and a second vaginal smear performed. Blood was collected on days 15 and 22. In 3-month-old females, estrus (by smears) was three times more frequent than in older mice, but mean concentrations of plasma and fecal estrogens never decreased with age. Collectively (not individually) plotted fecal estrogens values increased in the proestrus/estrus interphase (by smears) in 3-month-old mice only. Impedance typically peaked (4.5 Ω in 3-month-old mice) in the estrus phase, and only the prediction of estrus (highest area under the curve = 0.87 in 3-month-old) but not of other phases was possible. Regardless of age, individual cycle phase (by smears) never correlated with corresponding fecal estrogens, and estrus could not be predicted. In conclusion, while the fecal estrogens oscillation and frequency of estrus phase were affected by age, the systemic hormone release persisted. In mice, vaginal cytology did not reflect changes of systemic (fecal) estrogens, whereas impedance accurately identified estrus. The flaws and advantages of the examined monitoring methods should be considered in the design of future shock studies.

Lc3 over-expression improves survival and attenuates lung injury through increasing autophagosomal clearance in septic mice

OBJECTIVE

To clarify the role of autophagy in sepsis-induced lung injury.

BACKGROUND

The role of autophagy as a protective or maladaptive response in lung cells during sepsis has not yet been determined. The lack of specificity of the autophagic process has driven the development of new approaches that assess autophagosomes from formation to fusion with lysosomes.

METHODS

Sepsis was induced by cecal ligation and puncture (CLP). The autophagic process was manipulated using the pharmacological inhibitors of the autophagy pathway. Green fluorescent protein (GFP)-microtubule-associated protein 1 light chain 3 (LC3) transgenic mice were further used to determine the role of autophagy.

RESULTS

The formation of autophagosomal protein LC3-II progressively accumulated in the lungs over 24 hours after CLP, with the Lc3 gene expression returning to baseline levels at 24 hours. Autophagosome-lysosome fusion, however, gradually decreased from 8 to 24 hours after CLP, suggesting impaired clearance of autophagosomes rather than upregulation of autophagy in the septic lung. In contrast, transgenic mice overexpressing the Lc3 gene exhibited increased clearance of autophagosomes and improved survival after CLP. This protective effect was also seen in decreased cell death, inflammatory responses, neutrophil accumulation, albumin leakage, and edema formation. However, blockade of autophagosome-lysosome fusion with bafilomycin A1 abolished the protective effects in transgenic mice. This indicates that Lc3 transgene attenuates lung injury/inflammation in sepsis, possibly through increasing the clearance of autophagosomes.

CONCLUSIONS

Autophagy in the septic lung represents a protective response. However, autophagy, by virtue of excessive autophagosome accumulation, may play a maladaptive role in the late stage of sepsis, leading to acute lung injury.

Role of Akt/HO-1 pathway in estrogen-mediated attenuation of trauma-hemorrhage-induced lung injury

BACKGROUND

Despite advances in intensive care medicines, hemorrhagic shock leading to multiple organ failure remains the major causes of death in the injured host. Although studies have shown that 17β-estradiol (E2) prevents trauma-hemorrhage-induced lung damage, it remains unknown whether protein kinase B (Akt)/heme oxygenase (HO)-1 plays any role in E2-mediated lung protection after trauma-hemorrhage.

MATERIALS AND METHODS

After a 5-cm midline laparotomy, male rats underwent hemorrhagic shock (mean blood pressure ∼40 mm Hg for 90 min) followed by fluid resuscitation. At the onset of resuscitation, rats were treated with vehicle, E2 (1 kg/mg), E2 plus phosphoinositide 3-kinase inhibitor LY294002 (5 mg/kg), or LY294002. At 2 h after trauma-hemorrhage or sham operation, lung tissue myeloperoxidase activity, wet-to-dry-weight ratio, inflammatory mediators, and apoptosis were measured. Lung Akt, HO-1, and cleaved caspase-3 protein levels were also determined.

RESULTS

E2 attenuated the trauma-hemorrhage-induced increase in lung myeloperoxidase activity, edema formation, inflammatory mediator levels, and apoptosis, which was blocked by co-administration of LY294002. Administration of E2 normalized lung Akt phosphorylation and further increased HO-1 expression and decreased cleaved caspase-3 levels after trauma-hemorrhage. Co-administration of LY294002 prevented the E2-mediated attenuation of shock-induced lung injury.

CONCLUSIONS

Our results collectively suggest that Akt-dependent HO-1 upregulation may play a critical role in E2-meditated lung protection after trauma-hemorrhage.

EVI1 acts as an inducible negative-feedback regulator of NF-κB by inhibiting p65 acetylation

Inflammation is a hallmark of many important human diseases. Appropriate inflammation is critical for host defense; however, an overactive response is detrimental to the host. Thus, inflammation must be tightly regulated. The molecular mechanisms underlying the tight regulation of inflammation remain largely unknown. Ecotropic viral integration site 1 (EVI1), a proto-oncogene and zinc finger transcription factor, plays important roles in normal development and leukemogenesis. However, its role in regulating NF-κB-dependent inflammation remains unknown. In this article, we show that EVI1 negatively regulates nontypeable Haemophilus influenzae- and TNF-α-induced NF-κB-dependent inflammation in vitro and in vivo. EVI1 directly binds to the NF-κB p65 subunit and inhibits its acetylation at lysine 310, thereby inhibiting its DNA-binding activity. Moreover, expression of EVI1 itself is induced by nontypeable Haemophilus influenzae and TNF-α in an NF-κB-dependent manner, thereby unveiling a novel inducible negative feedback loop to tightly control NF-κB-dependent inflammation. Thus, our study provides important insights into the novel role for EVI1 in negatively regulating NF-κB-dependent inflammation, and it may also shed light on the future development of novel anti-inflammatory strategies.

Estrogen augments the protection of hypertonic saline treatment from mesenteric ischemia-reperfusion injury

Either estrogen or hypertonic saline (HTS) administration can decrease lung inflammation after ischemia-reperfusion. The present study investigated whether combined treatment with estrogen and HTS could provide further protection from mesenteric ischemia-reperfusion (MSIR) injury. Male C3H/HeOuJ mice were randomly segregated into the following groups: sham-operated (sham), vehicle treatment followed by MSIR (vehicle treated), estrogen treatment followed by MSIR (estrogen treated), HTS treatment and MSIR (HTS treated), and combined treatment of estrogen plus HTS and MSIR (combined treated). In MSIR, mice were subjected to mesenteric ischemia for 60 min followed by reperfusion for 30 min. The histology of the lung and the gut was obtained. Lung injury was evaluated by lung edema and myeloperoxidase (MPO) activity; lung protein expression of macrophage migration inhibitory factor (MIF), toll-like receptor-4 (TLR4), phosphorylated inhibitory κBα (p-IκBα), and inducible nitric oxide synthetase (iNOS) were assayed. Survival analysis was monitored after MSIR for 120 min. Compared with those in the sham-treated group, the lung water ratio, MPO activity, and expressions of MIF, TLR4, p-IκBα, and iNOS were significantly increased in the vehicle-treated group. Diminished MIF, TLR4, p-IκBα, and iNOS expressions were found in the estrogen-treated group, whereas suppression of p-IκBα and iNOS was found in the HTS-treated group. Treatment with estrogen or HTS decreased the lung water and MPO activity. The combined treatment of estrogen and HTS further significantly diminished p-IκBα and iNOS expression, lung edema, and MPO activity and improved the inflammation of the lung and the morphology of the gut in histology compared with the results of a single treatment of estrogen or HTS. Survival analysis showed significantly increased survival in the combination-treated group compared with survival in the HTS-treated group. In conclusion, compared with single-agent use, treatment combining estrogen and HTS further decreases lung p-IκBα and iNOS expressions, as well as the degree of lung injury. These effects may result in better rates of survival from MSIR injury.

The battle of the sexes: women win out in gastrointestinal surgery

BACKGROUND

Women have been shown to have worse outcomes compared with men after cardiac surgery, but fare better after traumatic injury. No study considers the impact of gender on outcomes after major gastrointestinal surgery. We hypothesize that the physiologic insults of a major abdominal operation are similar to an injury model; therefore, women will have improved outcomes.

MATERIAL AND METHODS

We performed a retrospective review of the NIS database from 1998 to 2007. Patients undergoing major gastrointestinal surgery were identified by ICD-9 procedure codes: esophageal (42.4), gastric (43.5-43.9), small intestine (45.6), large intestine (45.7-45.8 and 17.3), rectal (48.4-48.6), hepatic (50.2-50.3), biliary (51.3 and 51.6), and pancreatic (52.5-52.7). Exclusion criteria included age over 60 y and under 18 y, multiple operations, and a sexual developmental disorder (25.52, 75.27, and 25.9). The primary outcome measure was in-hospital death.

RESULTS

A total of 307,124 patients were identified, of whom 50.3% were women. Overall, there were 6574 (2.14%) deaths; 2.45% of men and 1.84% of women died (P < 0.001). In multivariate analysis, women were 21.1% less likely to die than men (OR = 0.789, 95% CI = 0.74-0.84). When subset analysis was performed, women had improved mortality in the following types of surgery: gastric (OR = 0.751, 95% CI = 0.60-0.94), small intestine (OR = 0.704, 95% CI = 0.63-0.79), large intestine (OR = 0.845, 95% CI = 0.77--0.93), hepatic (OR = 0.562, 95% CI = 0.41-0.77), and pancreatic (OR = 0.658, 95% CI = 0.49-0.89, see Fig. 1).

CONCLUSIONS

Our study demonstrates that women may have improved outcomes after some types of major gastrointestinal surgery; however, the mechanism by which this occurs is unclear. Future studies are needed to further evaluate this interesting phenomenon.

Mechanism of salutary effects of estrogen on cardiac function following trauma-hemorrhage: Akt-dependent HO-1 up-regulation

OBJECTIVES

Because administration of 17beta-estradiol following trauma-hemorrhage improves cardiovascular responses, we investigated whether the salutary effects of 17beta-estradiol on cardiac function are mediated via Akt-dependent heme oxygenase-1 up-regulation under those conditions.

DESIGN

Experimental animal study.

SETTING

University laboratory.

SUBJECTS

Male Sprague-Dawley rats.

INTERVENTIONS

Rats underwent trauma-hemorrhage (mean blood pressure approximately 40 mm Hg for 90 mins) followed by fluid resuscitation. Before resuscitation, rats received either vehicle, 17beta-estradiol (1 mg/kg), or 17beta-estradiol plus the phosphoinositide 3-kinase inhibitor wortmannin (1 mg/kg). At 2 hrs after trauma-hemorrhage or sham operation, the rats were killed.

MEASUREMENTS AND MAIN RESULTS

Cardiac function, heart tissue myeloperoxidase activity, cardiac and circulatory cytokine levels, cardiac intercellular adhesion molecule-1, and chemokine levels were measured. Cardiac Akt and heme oxygenase-1 were also determined. We found that 17beta-estradiol prevented the trauma-hemorrhage-induced impairment in cardiac function and increase in cardiac myeloperoxidase activity. Cardiac and systemic interleukin-6 and tumor necrosis factor-alpha levels as well as cardiac intercellular adhesion molecule-1, cytokine-induced neutrophil chemoattractant-1, and macrophage inflammatory protein-2 contents were increased following trauma-hemorrhage, which were normalized by 17beta-estradiol. Administration of 17beta-estradiol following trauma-hemorrhage restored cardiac Akt phosphorylation and further increased heme oxygenase-1 expression. Coadministration of wortmannin following trauma-hemorrhage abolished the previous effects by 17beta-estradiol.

CONCLUSIONS

These results suggest that the 17beta-estradiol-meditated improvement in cardiac function following trauma-hemorrhage occurs via Akt-dependent heme oxygenase-1 up-regulation.

Neutrophil chemokines and their role in IL-18-mediated increase in neutrophil O2- production and intestinal edema following alcohol intoxication and burn injury

We examined the role of interleukin (IL)-18 and cytokine-induced neutrophil chemokines (CINC)-1 and CINC-3 in the neutrophil release of superoxide anion (O2-) and elastase following alcohol/ethanol (EtOH) and burn injury. Male rats (approximately 250 g) were gavaged with EtOH to achieve a blood EtOH level of approximately 100 mg/dl before approximately 12.5% total body surface area burn or sham injury. Immediately after injury, rats were administered with anti-rat IL-18 antibody (80 microg/kg) or isotype control. After 20 min, anti-IL-18 antibody-treated rats were given either recombinant (r) rat CINC-1 or CINC-3. On day 1 after injury, the combined insult of EtOH and burn injury caused a significant increase in neutrophil elastase and O2- production as well as an increase in neutrophil accumulation, myeloperoxidase activity, and edema in the intestine. Treatment of rats with anti-IL-18 antibody normalized the above parameters. However, administration of rCINC-1 in anti-IL-18 antibody-treated rats increased the above parameters to levels similar to those observed following EtOH and burn injury. In contrast, administration of rCINC-3 did not influence the above parameters except neutrophil elastase. These findings indicate that IL-18 and CINC-1 may independently modulate neutrophil tissue-damaging actions following EtOH and burn injury. However, the finding that the treatment of rats with anti-IL-18 antibodies inhibits CINC-1 and CINC-3 supports the notion that IL-18 plays a critical role in increased neutrophil tissue-damaging action following a combined insult of EtOH intoxication and burn injury.

DSM-RX78, a new phosphodiesterase inhibitor, suppresses superoxide anion production in activated human neutrophils and attenuates hemorrhagic shock-induced lung injury in rats

Neutrophils are activated following hemorrhagic shock and the accumulation of neutrophils in the lung is associated with lung injury. This research investigated the effects of a semisynthetic 2-benzoylaminobenzoic acid derivative, methyl 2-(2-fluorobenzamido)benzoate (DSM-RX78), on superoxide anion (O(2)(-)) production in formyl-l-methionyl-l-leucyl-l-phenylalanine (FMLP)-activated human neutrophils, and on lung injury in Sprague-Dawley rats subjected to trauma-hemorrhage. DSM-RX78 concentration-dependently inhibited O(2)(-) production, but not elastase release, in FMLP-activated human neutrophils. DSM-RX78 displayed no superoxide-scavenging ability, and it failed to alter the subcellular NADPH oxidase activity. Significantly, DSM-RX78 increased cAMP formation and protein kinase (PK)A activity in FMLP-activated neutrophils, which occurred through the selective inhibition of cAMP-specific phosphodiesterase (PDE) activity but not an increase in adenylate cyclase function or cGMP-specific PDE activity. These results show that DSM-RX78 is a new inhibitor of cAMP-specific PDE. Moreover, DSM-RX78 reduced FMLP-induced phosphorylation of protein kinase B (Akt), but not calcium mobilization. The inhibitory effects of DSM-RX78 on O(2)(-) production and Akt phosphorylation were reversed by PKA inhibitors, suggesting that DSM-RX78 regulates O(2)(-) production of human neutrophils by promoting cAMP/PKA-dependent inhibition of Akt activation. On the other hand, administration of DSM-RX78 significantly attenuated the increase in myeloperoxidase activity and edema in the lung, as well as protein concentrations in bronchoalveolar lavage fluid in rats after trauma-hemorrhagic shock. In summary, these results strongly suggest that DSM-RX78 exerts anti-inflammatory effects, which result from the elevation of cAMP levels and PKA activity through its inhibition of cAMP-specific PDE. Also, our findings show that DSM-RX78 attenuates hemorrhagic shock-induced lung injury in rats.

The role of estrogen and receptor agonists in maintaining organ function after trauma-hemorrhage

Sex is increasingly recognized as a major factor in the outcome of patients who have trauma and sepsis. Moreover, sex steroids influence chemokine/adhesion molecule expression and neutrophil accumulation. Heat shock proteins, heat shock factor 1, and peroxisome proliferator-activated receptor [gamma] coactivator 1 are regulated by the estrogen receptors and consequently contribute to organ protection after trauma-hemorrhage. Additionally, sex steroids regulate inflammatory cytokines, leading to increased morbidity and mortality. This article deals with trauma-hemorrhage and examines the following: 1) the evidence for sex differences; 2) the mechanisms by which sex hormones affect organ protection; 3) the tissue-specific effect of sex hormone receptors; and 4) the effect of genomic and nongenomic (i.e. membrane-initiated steroid signaling) pathways of sex hormones after trauma. The available information indicates that sex steroids modulate cardiovascular responses after trauma. Thus, alteration or modulation of the prevailing hormone milieu at the time of injury seems to be a novel therapeutic option for improving outcome after injury

Mechanism of hepatoprotection in proestrus female rats following trauma-hemorrhage: heme oxygenase-1-derived normalization of hepatic inflammatory responses

Hepatic damage occurs in males and ovariectomized (OVX), not in proestrus (PE), females following trauma-hemorrhage (T-H). The mechanism responsible for hepatoprotection remains unknown. We hypothesized protection in PE is a result of enhanced heme oxygenase-1 (HO-1)-derived down-regulation of liver inflammatory responses. PE and OVX rats underwent T-H (midline laparotomy, 60% blood loss). PE rats received vehicle (Veh; saline), HO-1 inhibitor chromium mesoporphyrin IX chloride (CrMP; 2.5 mg/kg), zinc protoporphyrin IX (ZnPP; 25 mg/kg), or Akt/PI-3K inhibitor Wortmannin (Wort; 1 mg/kg) 30 min prior to resuscitation or sham operation i.p. OVX rats received Veh or 17beta-estradiol (E2; 1 mg/kg) 30 min before hemorrhage. Rats were killed 2 h thereafter. Following T-H, left ventricular performance was maintained in PE and E2 OVX rats but was depressed in OVX and CrMP-, ZnPP-, and Wort-treated PE rats; liver damage was not evident in PE rats, and CrMP, ZnPP, and Wort abrogated protection; liver HO-1, p38 MAPK, Akt/PI3K, and Bcl-2 expression increased in PE and E2 OVX rats, which was abrogated by CrMP, ZnPP, and Wort, and liver ICAM-1, caspase-3, phospho-IkappaB-alpha, and NF-kappaB expression increased in OVX and CrMP-, ZnPP-, and Wort-PE rats; liver myeloperoxidase, NF-kappaB DNA-binding activity, TNF-alpha, IL-6, plasma proinflammatory cytokines, and cytokine-induced neutrophil chemoattractants increased in OVX and CrMP-, ZnPP-, and Wort-PE rats; and plasma estradiol levels and hepatic estrogen receptor-alpha and -beta expression decreased in OVX but were unaltered by CrMP, ZnPP, and Wort. Thus, enhanced HO-1 in PE and E2 OVX females modulates inflammatory responses and protects liver following T-H.

Sex steroids/receptor antagonist: their use as adjuncts after trauma-hemorrhage for improving immune/cardiovascular responses and for decreasing mortality from subsequent sepsis

Studies in human as well as animal models demonstrate that females in the proestrus cycle (i.e., with high estrogen) tolerate trauma-hemorrhage and sepsis far better than males. The female sex steroid, estrogen, is the significant factor contributing to this observed gender difference in outcome. One reason for the lack of significant gender association in some clinical studies is the possibility of heterogeneity of the population in terms of their hormonal status at the time of injury. Several experimental investigations have revealed that androgens produce immune and cardiovascular depression after trauma-hemorrhage. However, the use of an androgen receptor antagonist after trauma-hemorrhage has salutary effects of immune and cardiovascular function. Likewise, estrogen produces beneficial effects on immune and cardiovascular function after trauma-hemorrhage and significantly decreases mortality rates from subsequent sepsis. The salutary effects of estrogen after trauma-hemorrhage have been shown to be due to both genomic and nongenomic effects. Thus, the use of an estrogen or androgen receptor antagonist as an adjunct after trauma-hemorrhage is a safe and novel approach for restoring immune and cardiovascular function after trauma-hemorrhage and for decreasing the mortality from subsequent sepsis.

Estrogen, NFkappaB, and the heat shock response

Estrogen has pleiotropic actions, among which are its anti-apoptotic, anti-inflammatory, and vasodilatory effects. Recently, an interaction between 17beta-estradiol (E2) and the transcription factor nuclear factor kappaB (NFkappaB) has been identified. NFkappaB has a central role in the control of genes involved in inflammation, proliferation, and apoptosis. Prolonged activation of NFkappaB is associated with numerous inflammatory pathological conditions. An important facet of E2 is its ability to modulate activity of NFkappaB via both genomic and nongenomic actions. E2 can activate NFkappaB rapidly via nongenomic pathways, increase cellular resistance to injury, and induce expression of the protective class of proteins, heat shock proteins (HSPs). HSPs can bind to many of the pro-apoptotic and pro-inflammatory targets of NFkappaB and, thus, indirectly inhibit many of its deleterious effects. In addition, HSPs can block NFkappaB activation and binding directly. Similarly, genomic E2 signaling can inhibit NFkappaB, but does so through alternative mechanisms. This review focuses on the molecular mechanisms of cross-talk between E2, NFkappaB, and HSPs, and the biological relevance of this cross-talk.

Acute alcohol intoxication potentiates neutrophil-mediated intestinal tissue damage after burn injury

This study examined whether acute alcohol (EtOH) intoxication before burn injury potentiates postburn intestinal tissue damage and whether neutrophils have any role in the damage under those conditions. Male rats ( approximately 250 g) were gavaged with EtOH to achieve a blood EtOH level of approximately 100 mg/dL or with saline and received either approximately 12.5% or approximately 25% total body surface area (TBSA) burn or sham injury. Rats were killed at 4 or 24 h after injury, and various parameters were measured. As compared with sham animals, burn injury alone (regardless of size) resulted in a significant increase in intestinal tissue myeloperoxidase (MPO; an index of neutrophil infiltration) activity and IL-18 levels 4 h after injury. Furthermore, rats receiving 25% TBSA, but not 12.5%, burn exhibited intestine edema. The IL-18 and MPO activity were normalized at 24 h after injury in rats receiving 12.5% TBSA burn, whereas these parameters remained elevated at 24 h in rats with 25% burn. The presence of EtOH in rats at the time of burn injury exacerbated the levels of IL-18, MPO activity, and edema at 4 and 24 h after burn injury. Treatment of rats with anti-IL-18 antibodies or with antineutrophil antiserum prevented the increase in the above parameters after EtOH and burn injury, except that the depletion of neutrophils did not prevent the IL-18 increase. In summary, these findings suggest that acute EtOH intoxication exacerbates postburn intestinal tissue damage after burn injury, and that it is, in part, neutrophil mediated.

Trauma and immune response--effect of gender differences

A major consequence of traumatic injury is immunosuppression. Findings from previous studies suggest that the depression of immune functions is severe in young males, ovariectomised and aged females. In contrast, the immune functions in proestrus females following trauma-haemorrhage are maintained. Studies have also shown that the survival rate in proestrus females following trauma-haemorrhage and the induction of subsequent sepsis is significantly higher than in age-matched males and ovariectomised females. Furthermore, administration of female sex hormone 17beta-oestradiol in males and ovariectomised females after trauma-haemorrhage prevents the suppression of immune response. Thus, these findings suggest that sex hormones play a significant role in shaping the host response following trauma. This article reviews studies delineating the mechanism by which sex hormones regulate immune cell functions in the experimental model of trauma-haemorrhage. The findings from the studies reviewed in this article suggest that sex steroids can be synthesised by the immune cell. The findings further indicate that T cell and macrophages express receptors for androgen and oestrogen. Since these cells are also the cells that produce cytokines, local synthesis of active steroids in these cells may become the significant factor in modulating their cytokine production.

17beta-Estradiol: a novel hormone for improving immune and cardiovascular responses following trauma-hemorrhage

17beta-Estradiol (i.e., estrogen or E2) is a female sex steroid, which plays an essential role in female reproductive physiology. However, several lines of evidence indicate that in addition to its role in reproductive physiology, E2 is critical for maintaining many other organ functions in stress conditions. These include immune, cardiovascular, and neuronal functions, as well as regulation of skin, bone, and lipid metabolism. Studies have examined the role of E2 as an adjunct in post-trauma responses, and this article will review whether E2 as an adjunct to fluid resuscitation following trauma-hemorrhage plays any role in improving/restoring immune and cardiovascular functions.

The critical role of vascular endothelial growth factor in pulmonary vascular remodeling after lung injury

The pulmonary vascular endothelial cell plays a crucial role in the regulation of the pulmonary vascular tone and in the maintenance of the barrier function and integrity of the alveolar-capillary membrane. It also plays a major role in coagulation, fibrinolysis, and angiogenesis and participates in inflammatory reactions. Vascular endothelial growth factor (VEGF) is a central growth and survival factor for the endothelial cell. Particularly high levels of VEGF are expressed in the lungs, reflecting the critical role of VEGF for lung development and structural integrity of the adult lung. Vascular endothelial growth factor exerts a variety of physiological and pathophysiological actions in the lung. Recent evidence suggests its involvement in the pathogenesis of lung diseases such as bronchopulmonary dysplasia, acute lung injury, emphysema, and pulmonary hypertension. To summarize the critical effects of VEGF on the pulmonary endothelial cell in the pathogenesis of these diseases, the purposes of this review are to (1) discuss the biological activities and intracellular signaling pathways of VEGF in the lung; (2) summarize the regulatory mechanisms involved in VEGF expression; (3)address the effects of VEGF on endothelial cells in hyperoxia-induced and other forms of lung injury; (4) highlight the endothelial effects of VEGF in the pathogenesis of emphysema; and (5) explore the role of VEGF in the pathogenesis of pulmonary arterial hypertension.

Metabolic modulators following trauma sepsis: Sex hormones

BACKGROUND

The development of metabolic perturbations following severe trauma/sepsis leading to decreased energy production, hyperglycemia, and lipolysis is often rapid. Gender is increasingly recognized as a major factor in the outcome of patients suffering from trauma/sepsis. Moreover, sex hormones influence energy, glucose, and lipid metabolism. Metabolic modulators, such as peroxisome proliferator-activated receptor-gamma coactivator-1 and peroxisome proliferator-activated receptor-alpha, which are required for mitochondrial energy production and fatty acid oxidation, are regulated by the estrogen receptor-beta and consequently contribute to cardioprotection following trauma hemorrhage. Additionally, sex steroids regulate inflammatory cytokines that cause hypermetabolism/catabolism via acute phase response, leading to increased morbidity and mortality.

MEASUREMENTS

This article examines the following: (1) the evidence for gender differences; (2) energy, glucose, and lipid metabolism and the acute phase protein response; (3) the mechanisms by which gender/sex hormones affect the metabolic modulators; and (4) the tissue-specific effect of sex hormone receptors and the effect of genomic and nongenomic pathways of sex hormones following trauma.

RESULTS AND CONCLUSIONS

The available information indicates that sex steroids not only modulate the immune/cardiovascular responses but also influence various metabolic processes following trauma. Thus, alteration or modulation of the prevailing hormone milieu at the time of injury appears to be a novel therapeutic adjunct for improving outcome after injury.

Downregulation of migration inhibitory factor is critical for estrogen-mediated attenuation of lung tissue damage following trauma-hemorrhage

Although studies have shown that 17β-estradiol (E2) prevents neutrophil infiltration and organ damage following trauma-hemorrhage, the mechanism by which E2inhibits neutrophil transmigration remains unknown. Macrophage migration inhibitory factor (MIF) is thought to play a central role in exacerbation of inflammation and is associated with lung injury. MIF regulates the inflammatory response through modulation of Toll-like receptor 4 (TLR4). Activation of TLR4 results in the release of proinflammatory cytokines and chemokines, which induce neutrophil infiltration and subsequent tissue damage. We hypothesized that E2mediates its salutary effects in the lung following trauma-hemorrhage via negative regulation of MIF and modulation of TLR4 and cytokine-induced chemotaxis. C3H/HeOuJ mice were subjected to trauma-hemorrhage (mean blood pressure 35 ± 5 mmHg for ∼90 min, then resuscitation) or sham operation. Mice received vehicle, E2, or E2in combination with recombinant mouse MIF protein (rMIF). Trauma-hemorrhage increased lung MIF and TLR4 protein levels as well as lung and systemic levels of cytokines/chemokines. Treatment of animals with E2following trauma-hemorrhage prevented these changes. However, administration of rMIF protein with E2abolished the E2-mediated decrease in lung TLR4 levels, lung and plasma levels of IL-6, TNF-α, monocyte chemoattractant protein-1, and keratinocyte-derived chemokine (KC). Administration of rMIF protein also prevented E2-mediated reduction in neutrophil influx and tissue damage in the lungs following trauma-hemorrhage. These results suggest that the protective effects of E2on lung injury following trauma-hemorrhage are mediated via downregulation of lung MIF and TLR4-induced cytokine/chemokine production.

Acute alcohol intoxication increases interleukin-18-mediated neutrophil infiltration and lung inflammation following burn injury in rats

In this study, we examined whether IL-18 plays a role in lung inflammation following alcohol (EtOH) and burn injury. Male rats (∼250 g) were gavaged with EtOH to achieve a blood EtOH level of ∼100 mg/dl before burn or sham injury (∼12.5% total body surface area). Immediately after injury, rats were treated with vehicle, caspase-1 inhibitor AC-YVAD-CHO to block IL-18 production or with IL-18 neutralizing anti-IL-18 antibodies. In another group, rats were treated with anti-neutrophil antiserum ∼16 h before injury to deplete neutrophils. On day 1 after injury, lung tissue IL-18, neutrophil chemokines (CINC-1/CINC-3), ICAM-1, neutrophil infiltration, MPO activity, and water content (i.e., edema) were significantly increased in rats receiving a combined insult of EtOH and burn injury compared with rats receiving either EtOH intoxication or burn injury alone. Treatment of rats with caspase-1 inhibitor prevented the increase in lung tissue IL-18, CINC-1, CINC-3, ICAM-1, MPO activity, and edema following EtOH and burn injury. The increase in lung IL-18, MPO, and edema was also prevented in rats treated with anti-IL-18 antibodies. Furthermore, administration of anti-neutrophil antiserum also attenuated the increase in lung MPO activity and edema, but did not prevent the increase in IL-18 levels following EtOH and burn injury. These findings suggest that acute EtOH intoxication before burn injury upregulates IL-18, which in turn contributes to increased neutrophil infiltration. Furthermore, the presence of neutrophils appears to be critical for IL-18-meditaed increased lung tissue edema following a combined insult of EtOH and burn injury.