Enhanced immune responses in females, as opposed to decreased responses in males following haemorrhagic shock and resuscitation

Pioglitazone reverses alcohol-induced alterations in alveolar macrophage mitochondrial phenotype

BACKGROUND

People with alcohol use disorder (AUD) have an increased risk of developing pneumonia and pulmonary diseases. Alveolar macrophages (AMs) are immune cells of the lower respiratory tract that are necessary for clearance of pathogens. However, alcohol causes AM oxidative stress, mitochondrial damage and dysfunction, and diminished phagocytic capacity, leading to lung injury and immune suppression.

METHODS

AMs were isolated by bronchoalveolar lavage from people with AUD and male and female C57BL/6J mice given chronic ethanol (20% w/v, 12 weeks) in drinking water. The peroxisome proliferator-activated receptor γ ligand, pioglitazone, was used to treat human AMs ex vivo (10 μM, 24 h) and mice in vivo by oral gavage (10 mg/kg/day). Levels of AM mitochondrial superoxide and hypoxia-inducible factor-1 alpha (HIF-1α) mRNA, a marker of oxidative stress, were measured by fluorescence microscopy and RT-qPCR, respectively. Mouse AM phagocytic ability was determined by internalized Staphylococcus aureus, and mitochondrial capacity, dependency, and flexibility for glucose, long-chain fatty acid, and glutamine oxidation were measured using an extracellular flux analyzer. In vitro studies used a murine AM cell line, MH-S (±0.08% ethanol, 72 h) to investigate mitochondrial fuel oxidation and ATP-linked respiration.

RESULTS

Pioglitazone treatment decreased mitochondrial superoxide in AMs from people with AUD and ethanol-fed mice and HIF-1α mRNA in ethanol-fed mouse lungs. Pioglitazone also reversed mouse AM glutamine oxidation and glucose or long-chain fatty acid flexibility to meet basal oxidation needs. In vitro, ethanol decreased the rate of AM mitochondrial and total ATP production, and pioglitazone improved changes in glucose and glutamine oxidation.

CONCLUSIONS

Pioglitazone reversed chronic alcohol-induced oxidative stress in human AM and mitochondrial substrate oxidation flexibility and superoxide levels in mouse AM. Decreased ethanol-induced AM HIF-1α mRNA with pioglitazone suggests that this pathway may be a focus for metabolic-targeted therapeutics to improve morbidity and mortality in people with AUD.

Do Females Have Worse Outcomes in Penetrating Trauma: A Single-Center Analysis

INTRODUCTION

Penetrating trauma occurs less frequently in females than in males. Studies on penetrating injuries are conducted in predominantly male populations. We aim to elucidate the demographics and outcomes of penetrating trauma specifically in females to mitigate disparities of care in females.

MATERIALS AND METHODS

A retrospective review of hospitalized adult trauma patients suffering penetrating trauma from 2015 to 2021 was performed in an urban American College of Surgeon-verified level 1 trauma center. Patients were stratified by sex (females or males) and mechanism of injury (gun-related versus nongun-related). The primary outcome was mortality, and secondary outcomes included incidence of blood transfusion, incidence of surgical/interventional radiology (IR) interventions, hospital length of stay (LOS), and complications. Descriptive statistics were employed with a significance defined as P value <0.05. A multivariate logistic regression was used to determine the impact of sex on mortality, surgical/IR interventions, and hospital LOS.

RESULTS

Females with penetrating injury had lower Injury Severity Score (1 versus 4, P < 0.05) than males, but had similar mortality rates (4% versus 6%, P = 0.06). In multivariable logistic analysis adjusting for age and Injury Severity Score, while females experience 33% fewer OR/IR intervention, there was no statistically significant difference in mortality rates, hospital LOS, and complication rates between males and females.

CONCLUSIONS

Despite receiving fewer surgical/IR intervention, females with penetrating injuries have similar outcomes to their male counterparts. Further study is needed to study this discrepancy.

Construction and validation of a novel and severe hepatic injury model in swine focuses on research and training. Observational study

Some hepatic wound models have been developed in pigs with the aim of reproducing liver injury; however, the wound shape, severity, and outcome differ among them. The novel injury profile employed in this study differed from that used elsewhere for standardized, repeatable, reproducible, incising-penetrating, vascular, and severe injury in swine. It is made with a cutting object that penetrates deep into the hepatic parenchyma, always affecting the two suprahepatic veins at the point where they merge into the common trunk. The primary outcome was reproducibility and replicability of the surgical method. The secondary outcome was the analysis of some variables (blood loss, survival, and flow) to validate the model. •This novel method of liver injury provides a liver injury with the following characteristics: standardized, incise-penetrated, deep, bloody, and severe.•This model can be used for research (trauma, hepato-bilio-pancreatic, pharmaceutical) and training (damage control surgery).•Method name: Incising-Penetrating, Vascular and Severe Liver Injury Model in Swine.

Females have a different metabolic response to critical illness, measured by comprehensive amino acid flux analysis

BACKGROUND

The trajectory from healthy to critical illness is influenced by numerous factors, including metabolism, which differs substantially between males and females. Whole body protein breakdown is substantially increased in critically ill patients, but it remains unclear whether there are sex differences that could explain the different health outcomes. Hence, we performed a secondary analysis of a study, where we used a novel pulse isotope method in critically ill and matched healthy males and females.

METHODS

In 51 critically ill ICU patients (26 males, 15 females) and 49 healthy controls (36 males and 27 females), we assessed their general and disease characteristics and collected arterial(ized) blood in the postabsorptive state after pulse administration of 8 ml of a solution containing 18 stable AA tracers. In contrast to the original study, we now fitted the decay curves and calculated non-compartmental whole body amino acid production (WBP) and compartmental measurements of metabolism, including intracellular amino acid production. We measured amino acid enrichments and concentrations by LC-MS/MS and derived statistics using AN(C)OVA.

RESULTS

Critically ill males and females showed an increase in the WBP of many amino acids, including those related to protein breakdown, but females showed greater elevations, or in the event of a reduction, attenuated reductions. Protein breakdown-independent WBP differences remained between males and females, notably increased glutamine and glutamate WBP. Only severely ill females showed a lower increase in WBP of many amino acids in comparison to moderately ill females, suggesting a suppressed metabolism. Compartmental analysis supported the observations.

CONCLUSIONS

The present study shows that females have a different response to critical illness in the production of several amino acids and changes in protein breakdown, observations made possible using our innovative stable tracer pulse approach.

CLINICAL TRIAL REGISTRY

Data are from the baseline measurements of study NCT02770092 (URL: https://clinicaltrials.gov/ct2/show/NCT02770092) and NCT03628365 (URL: https://clinicaltrials.gov/ct2/show/NCT03628365).

Selective Inhibition of IL-6 Trans-Signaling Has No Beneficial Effect on the Posttraumatic Cytokine Release after Multiple Trauma in Mice

While improvements in pre-hospital and in-hospital care allow more multiple trauma patients to advance to intensive care, the incidence of posttraumatic multiple organ dysfunction syndrome (MODS) is on the rise. Herein, the influence of a selective IL-6 trans-signaling inhibition on posttraumatic cytokine levels was investigated as an approach to prevent MODS caused by a dysbalanced posttraumatic immune reaction. Therefore, the artificial IL-6 trans-signaling inhibitor sgp130Fc was deployed in a murine multiple trauma model (femoral fracture plus bilateral chest trauma). The traumatized mice were treated with sgp130Fc (FP) and compared to untreated mice (WT) and IL-6 receptor knockout mice (RKO), which received the same traumas. The overall trauma mortality was 4.4%. Microscopic pulmonary changes were apparent after multiple trauma and after isolated bilateral chest trauma. Elevated IL-6, MCP-3 and RANTES plasma levels were measured after trauma, indicating a successful induction of a systemic inflammatory reaction. Significantly reduced IL-6 and RANTES plasma levels were visible in RKO compared to WT. Only a little effect was visible in FP compared to WT. Comparable cytokine levels in WT and FP indicate neither a protective nor an adverse effect of sgp130Fc on the cytokine release after femoral fracture and bilateral chest trauma.

Acute suppurative thyroiditis due to Streptococcus anginosus leading to sepsis and acute respiratory distress syndrome: a case report

Acute suppurative thyroiditis (AST) is a rare but potentially life-threatening thyroid disease with a high mortality if left untreated. Thus, differentiation from other thyroid disorders is highly important in clinical practice. A 22-year-old male patient was admitted to a tertiary care hospital with cervical pain, palpitations, thyrotoxicosis, and an inhomogeneously enlarged right thyroid lobe. In view of the clinical findings, subacute thyroiditis (SAT) was suspected and treatment with glucocorticoids was started. After initial amelioration, the patient developed cervical erythema, fever, and recurrent pain. A CT scan showed extensive phlegmonous inflammation and abscess formation, suggestive of AST. We started immediate empiric antibiotic therapy and performed surgical drainage of the abscess formations. Subsequently, the patient developed hypoxic respiratory failure, leading to ICU admission and intermittent need for non-invasive ventilation. Blood and abscess cultures were positive for Streptococcus anginosus. If left untreated, AST represents a potentially life-threatening disease. Thus, in clinically doubtful cases, liberal further assessment by means of cervical CT scans or fine needle aspiration biopsy are strongly advised.

Sex- and Gender-Dependent Differences in Clinical and Preclinical Sepsis

ABSTRACT

In this mini-review we provide an overview of sex- and gender-dependent issues in both clinical and preclinical sepsis. The increasing recognition for the need to account for sex and gender in biomedical research brings a unique set of challenges and requires researchers to adopt best practices when conducting and communicating sex- and gender-based research. This may be of particular importance in sepsis, given the potential contribution of sex bias in the failures of translational sepsis research in adults and neonates. Clinical evidence of sex-dependent differences in sepsis is equivocal. Since clinical studies are limited to observational data and confounded by a multitude of factors, preclinical studies provide a unique opportunity to investigate sex differences in a controlled, experimental environment. Numerous preclinical studies have suggested that females may experience favorable outcomes in comparison with males. The underlying mechanistic evidence for sex-dependent differences in sepsis and other models of shock (e.g., trauma-hemorrhage) largely centers around the beneficial effects of estrogen. Other mechanisms such as the immunosuppressive role of testosterone and X-linked mosaicism are also thought to contribute to observed sex- and gender-dependent differences in sepsis. Significant knowledge gaps still exist in this field. Future investigations can address these gaps through careful consideration of sex and gender in clinical studies, and the use of clinically accurate preclinical models that reflect sex differences. A better understanding of sex-and gender-dependent differences may serve to increase translational research success.

Estrogen deficiency - a central paradigm in age-related impaired healing?

Wound healing is a dynamic biological process achieved through four sequential, overlapping phases; hemostasis, inflammation, tissue proliferation and remodeling. For effective wound healing, all four phases must occur in the appropriate order and time frame. It is well accepted that the wound healing process becomes disrupted in the elderly, increasing the propensity of non-healing wound states that can lead to substantial patient morbidity and an enormous financial burden on healthcare systems. Estrogen deprivation in the elderly has been identified as the key driver of age-related delayed wound healing in both genders, with topical and systemic estrogen replacement reversing the detrimental effects of aging on wound repair. Evidence suggests estrogen deprivation may contribute to the development of chronic wound healing states in the elderly but research in this area is somewhat limited, warranting further investigations. Moreover, although the beneficial effects of estrogen on cutaneous healing have been widely explored, the development of estrogen-based treatments to enhance wound repair in the elderly have yet to be widely exploited. This review explores the critical role of estrogen in reversing age-related impaired healing and evaluates the prospect of developing more focused novel therapeutic strategies that enhance wound repair in the elderly via activation of specific estrogen signaling pathways in regenerating tissues, whilst leaving non-target tissues largely unaffected.

Estrogen Alleviates Sex-Dependent Differences in Lung Bacterial Clearance and Mortality Secondary to Bacterial Pneumonia after Traumatic Brain Injury

Traumatic brain injury (TBI) is the leading cause of injury-related death and disability in patients under the age of 46 years. Survivors of the initial injury often endure systemic complications such as pulmonary infection, and Pseudomonas aeruginosa is one of the most common causes of nosocomial pneumonia in intensive care units. Female patients are less likely to develop secondary pneumonia after TBI, and pre-clinical studies have revealed a salutary role for estrogen after trauma. Therefore, we hypothesized that female mice would experience less mortality after post-TBI pneumonia with P. aeruginosa. We employed a mouse model of TBI followed by P. aeruginosa pneumonia. Male mice had greater mortality and impaired lung bacterial clearance after post-TBI pneumonia compared with female mice. This was confirmed as a difference in sex hormones, as oophorectomized wild-type mice had mortality and lung bacterial clearance similar to male mice. There were differences in tumor necrosis factor-α secretion in male and female alveolar macrophages after P. aeruginosa infection. Finally, injection of male or oophorectomized wild-type female mice with estrogen restored lung bacterial clearance and prevented mortality. Our model of TBI followed by P. aeruginosa pneumonia is among the first to reveal sex dimorphism in secondary, long-term TBI complications.

Sex differences in fracture outcomes within Taiwan population: A nationwide matched study

Background and aims

Because the sex difference in outcomes of fracture was incompletely understood, we evaluated the post-fracture complications and mortality of female and male patients.

Methods

We conducted a nationwide study of 498,586 fracture patients who received inpatient care using Taiwan’s National Health Insurance Research Database 2008–2013 claims data. Female and male fracture patients were selected for comparison by using a propensity-score matching procedure. Age, low income, types of fracture, fracture with surgery, several medical conditions, number of hospitalization and emergency visits were considered as potential confounding factors. Multivariate logistic regressions were used to calculate the adjusted odds ratios (OR), the 95% CI of post-fracture complications and 30-day in-hospital mortality differences between women and men.

Results

Male patients had a higher risk of post-fracture pneumonia (OR 1.96, 95% CI 1.83–2.11), acute renal failure (OR 1.85, 95% CI 1.60–2.15), deep wound infection (OR 1.63, 95% CI 1.51–1.77), stroke (OR 1.58, 95% CI 1.49–1.67), septicemia (OR 1.51, 95% CI 1.42–1.61), acute myocardial infarction (OR 1.38, 95% CI 1.09–1.75) and 30-day in-hospital mortality (OR 1.69, 95% CI 1.48–1.93) compared with female patients. However, a lower risk of post-fracture urinary tract infection (OR 0.69, 95% CI 0.65–0.72) was found in men than in women. Male patients also had longer hospital stays and higher medical expenditures due to fracture admission than did the female patients. Higher rates of post-fracture adverse events in male patients were noted in all age groups and all types of fractures.

Conclusion

We raised the possibility that male patients showed more complications and higher mortality rates after fracture admission compared with female patients, with the exception of urinary tract infections.

The Importance of Sex Differences on Outcome after Major Trauma: Clinical Outcome in Women Versus Men

Purpose: The purpose of this study was to evaluate epidemiological and clinically relevant sex-related differences in polytraumatized patients at a Level 1 Trauma Center. Methods: 646 adult patients (210 females and 436 males) who were classified as polytraumatized (at the point of admission) and treated at our Level I Trauma Center were reviewed and included in this study. Demographic data as well as mechanism of injury, injury severity, injury pattern, frequency of preclinical intubation, hemodynamic variables on admission, time of mechanical ventilation and of intensive care unit (ICU) treatment, as well as the incidence of acute respiratory distress syndrome (ARDS), multi organ failure (MOF), and mortality were extracted and analyzed. Results: A total of 210 female and 436 male patients formed the basis of this report. Females showed a higher mean age (44.6 vs. 38.3 years; p < 0.0001) than their male counterparts. Women were more likely to be injured as passengers or by suicidal falls whereas men were more likely to suffer trauma as motorcyclists. Following ICU treatment, female patients resided significantly longer at the casualty ward than men (27.1 days vs. 20.4 days, p = 0.013) although there was no significant difference regarding injury severity, hemodynamic variables on admission, and incidence of MOF, ARDS, and mortality. Conclusion: The positive correlation of higher age and longer in-hospital stay in female trauma victims seems to show women at risk for a prolonged in-hospital rehabilitation time. A better understanding of the impact of major trauma in women (but also men) will be an important component of efforts to improve trauma care and long-term outcome.

Gender differences in response to abdominal compartment syndrome in rats

Objective

Our study aims to emphasize the novelty of female rats in regard to their hemodynamic changes in response to abdominal compartment syndrome. A group of 64 rats was randomly divided into 4 subgroups for each gender. Except for the control, intra-abdominal pressure was increased to 10, 20, 30 mmHg. Survival time, mean arterial pressure, pH and lactate were determined at different time intervals.

Results

As IAP was 20 mmHg, a statistically difference was seen between the male group and the female group starting from 15 min (126 ± 9.7 mmHg, 124 ± 14.7 mmHg respectively, p < 0.02) and lasting 2 h. At 30 mmHg, a statistically difference was seen between 30 to 60 min (p < 0.05). Only group 2 presented results with statistical power both at 30 and at 60 min concerning pH (p = 0.003, p < 0.001 respectively). In the lactate measurements at IAP of 10 mmHg, at 60 min male lactate level was 3.93 ± 1.13 and 2.25 ± 0.33 in female rats (p = 0.034). Female rats that were subjected to IAP of 20 mmHg and 30 mmHg had significantly better survival than male rats that were subjected to the same pressure (p < 0.05 and p < 0.01, respectively). We concluded that female rats have better preserved their hemodynamic and metabolic parameters during ACS than male rats.

Effects of burns on gut motor and mucosa functions

This review analyzed the published studies on the effects of thermal injury on gastrointestinal motility and mucosal damage. Our strategy was to integrate all available evidence to provide a complete review on the prokinetic properties of variable reagents and the potential clinical treatment of mucosal damage and gastrointestinal dysmotility after thermal injury. We classified the studies into two major groups: studies on gastrointestinal dysmotility and studies on mucosal damage. We also subclassified the studies into 3 parts: stomach, small intestine, and colon. This review shows evidence that ghrelin can recover burn-induced delay in gastric emptying and small intestinal transit, and can protect the gastric mucosa from burn-induced injury. Oxytocin and β-glucan reduced the serum inflammatory mediators, and histological change and mucosal damage indicators, but did not show evidence of having the ability to recover gastrointestinal motility. Using a combination of different reagents to protect the gastrointestinal mucosa against damage and to recover gastrointestinal motility is an alternative treatment for thermal injury.

Gender differences in murine pulmonary responses elicited by cellulose nanocrystals

Background

Cellulose-based materials have been used for centuries to manufacture different goods derived from forestry and agricultural sources. In the growing field of nanocellulose applications, its uniquely engineered properties are instrumental for inventive products coming to competitive markets. Due to their high aspect ratio and stiffness, it is speculated that cellulose nanocrystals (CNC) may cause similar pulmonary toxicity as carbon nanotubes and asbestos, thus posing a potential negative impact on public health and the environment.

Methods

The present study was undertaken to investigate the pulmonary outcomes induced by repeated exposure to respirable CNC. C57BL/6 female and male mice were exposed by pharyngeal aspiration to CNC (40 μg/mouse) 2 times a week for 3 weeks. Several biochemical endpoints and pathophysiological outcomes along with gene expression changes were evaluated and compared in the lungs of male and female mice.

Results

Exposure to respirable CNC caused pulmonary inflammation and damage, induced oxidative stress, elevated TGF-β and collagen levels in lung, and impaired pulmonary functions. Notably, these effects were markedly more pronounced in females compared to male mice. Moreover, sex differences in responses to pulmonary exposure to CNC were also detected at the level of global mRNA expression as well as in inflammatory cytokine/chemokine activity.

Conclusions

Overall, our results indicate that there are considerable differences in responses to respirable CNC based on gender with a higher pulmonary toxicity observed in female mice.

Electronic supplementary material

The online version of this article (doi:10.1186/s12989-016-0140-x) contains supplementary material, which is available to authorized users.

Neither Single nor a Combination of Routine Laboratory Parameters can Discriminate between Gram-positive and Gram-negative Bacteremia

Adequate early empiric antibiotic therapy is pivotal for the outcome of patients with bloodstream infections. In clinical practice the use of surrogate laboratory parameters is frequently proposed to predict underlying bacterial pathogens; however there is no clear evidence for this assumption. In this study, we investigated the discriminatory capacity of predictive models consisting of routinely available laboratory parameters to predict the presence of Gram-positive or Gram-negative bacteremia. Major machine learning algorithms were screened for their capacity to maximize the area under the receiver operating characteristic curve (ROC-AUC) for discriminating between Gram-positive and Gram-negative cases. Data from 23,765 patients with clinically suspected bacteremia were screened and 1,180 bacteremic patients were included in the study. A relative predominance of Gram-negative bacteremia (54.0%), which was more pronounced in females (59.1%), was observed. The final model achieved 0.675 ROC-AUC resulting in 44.57% sensitivity and 79.75% specificity. Various parameters presented a significant difference between both genders. In gender-specific models, the discriminatory potency was slightly improved. The results of this study do not support the use of surrogate laboratory parameters for predicting classes of causative pathogens. In this patient cohort, gender-specific differences in various laboratory parameters were observed, indicating differences in the host response between genders.

Gender-Specific Effects on Immune Response and Cardiac Function after Trauma Hemorrhage and Sepsis

Background

Studies in human as well as animal models indicate a gender-specific responsiveness of the immune and organ systems with regard to shock, trauma, and sepsis.

Methods

A literature review was performed.

Results

Cell-mediated immune responses and cardiovascular functions are suppressed in males following trauma hemorrhage, whereas they are maintained or even enhanced in females in the proestrus state of the estrus cycle. Experimental studies have demonstrated that divergent immune responses in males and females following adverse circulatory conditions are mediated by the gender-specific hormones testosterone and estrogen. Several clinical trials, however, failed to demonstrate a significant association of gender and inflammatory response. This may be explained by the heterogeneity of the population in terms of their hormonal status at the time of injury.

Conclusions

With regard to the underlying mechanisms, receptors for sex hormones have been identified on various immune cells, suggesting direct effects of these hormones on immune function. Alternatively, indirect effects of sex steroids such as changes in cardiovascular responses or androgen- and estrogen-synthesizing enzymes might contribute to gender-specific immune responses. Clinical studies suggest that sex hormones, such as dehydroepiandrosterone, modulate the function of peripheral blood mononuclear cells also following abdominal surgery. Thus, sex hormones, receptor antagonists, and sex steroid-synthesizing enzymes might be useful in the future for modulating the complex immune responses after trauma hemorrhage and sepsis.

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.

Sex- and diagnosis-dependent differences in mortality and admission cytokine levels among patients admitted for intensive care

OBJECTIVES

To investigate the role of sex on cytokine expression and mortality in critically ill patients.

DESIGN

A cohort of patients admitted to were enrolled and followed over a 5-year period.

SETTING

Two university-affiliated hospital surgical and trauma ICUs.

PATIENTS

Patients 18 years old and older admitted for at least 48 hours to the surgical or trauma ICU.

INTERVENTIONS

Observation only.

MEASUREMENTS AND MAIN RESULTS

Major outcomes included admission cytokine levels, prevalence of ICU-acquired infection, and mortality during hospitalization conditioned on trauma status and sex. The final cohort included 2,291 patients (1,407 trauma and 884 nontrauma). The prevalence of ICU-acquired infection was similar for men (46.5%) and women (44.5%). All-cause in-hospital mortality was 12.7% for trauma male patient and 9.1% for trauma female patient (p = 0.065) and 22.9% for nontrauma male patients and 20.6% for nontrauma female patients (p = 0.40). Among trauma patients, logistic regression analysis identified female sex as protective for all-cause mortality (odds ratio, 0.57). Among trauma patients, men had significantly higher admission serum levels of interleukin-2, interleukin-12, interferon-γ, and tumor necrosis factor-α, and among nontrauma patients, men had higher admission levels of interleukin-8 and tumor necrosis factor-α.

CONCLUSIONS

The relationship between sex and outcomes in critically ill patients is complex and depends on underlying illness. Women appear to be better adapted to survive traumatic events, while sex may be less important in other forms of critical illness. The mechanisms accounting for this gender dimorphism may, in part, involve differential cytokine responses to injury, with men expressing a more robust proinflammatory profile.

Women are more than twice as likely to die from burns as men in Australia and New Zealand: an unexpected finding of the Burns Evaluation And Mortality (BEAM) Study

While the risk of death after nonthermal trauma and sepsis may be higher for men, sex differences in outcome after burns are inconsistently reported. The Burns Evaluation And Mortality Study examined the outcomes of all patients admitted after thermal injury to the intensive care unit (ICU) at 8 of 9 burn referral centers in Australia and New Zealand between January 1, 2005, and December 31, 2011. There were 348 women and 1367 men treated for acute burns. Women were older, had more extensive burns, and higher severity of illness scores. Women spent longer in hospital and in ICU than men. Mortality among women was higher than in men (21% vs 8.3%, P<.001). Trends toward a survival disadvantage for women were seen across all ages, at all levels of severity of illness, at every proportion of body surface area burnt, and across all centers. After adjusting for confounding factors, women had more than double the risk of death compared with men (odds ratio, 2.35; 95% confidence interval, 1.38-4.01; P=.002). Our study conclusively shows worse outcomes for women with burns admitted to ICUs in Australia and New Zealand. Further research is required to determine why this is happening.

LPS resistance of SPRET/Ei mice is mediated by Gilz, encoded by the Tsc22d3 gene on the X chromosome

Natural variation for LPS-induced lethal inflammation in mice is useful for identifying new genes that regulate sepsis, which could form the basis for novel therapies for systemic inflammation in humans. Here we report that LPS resistance of the inbred mouse strain SPRET/Ei, previously reported to depend on the glucocorticoid receptor (GR), maps to the distal region of the X-chromosome. The GR-inducible gene Tsc22d3, encoding the protein Gilz and located in the critical region on the X-chromosome, showed a higher expressed SPRET/Ei allele, regulated in cis. Higher Gilz levels were causally related to reduced inflammation, as shown with knockdown and overexpression studies in macrophages. Transient overexpression of Gilz by hydrodynamic plasmid injection confirmed that Gilz protects mice against endotoxemia Our data strongly suggest that Gilz is responsible for the LPS resistance of SPRET/Ei mice and that it could become a treatment option for sepsis.

Role for gender in colorectal cancer risk: a Taiwan population-based study

BACKGROUND AND AIMS

Gender differences in the prognosis of colorectal cancer (CRC) remain controversial. The aim of this study was to complete a comprehensive analysis of gender differences in CRC survival derived from population registries in Taiwan.

MATERIALS AND METHODS

We analyzed survival data for patients diagnosed with CRC between 1998 and 2005 derived from the Taiwan Cancer Registry database. During this time period, 65,113 patients were registered, and 62,060 patients were eligible. Gender differences in overall survival and cancer-specific survival were analyzed by use of the Kaplan-Meier method. We then modeled the risk in different genders by use of a multivariate proportional hazard (Cox) model adjusting for possible confounders of survival.

RESULTS

The 5-year period overall and cancer-specific survivals were significantly higher in women than in men [51.84% (95% confidence interval (CI), 51.22-52.46) vs. 47.68% (95% CI, 47.14-48.22), log-rank p < 0.001; and 56.44% (95% CI, 55.82-57.07) vs. 53.47 % (95 % CI, 52.92-54.01), log-rank p < 0.001, respectively]. Subgroup analysis revealed higher overall and cancer-specific survivals in women between 50 and 80 years age and those with adenocarcinomas (p < 0.001). By use of Cox modeling, we noted a decreased hazard ratio (HR) for death from CRC in women compared with men (HR, 0.820-0.971), especially in the 50-80-year age group. All estimated HRs, after adjusting for age, tumor histology, and tumor site, had significant trends of a decreasing risk of death from CRC in women.

CONCLUSIONS

Our findings suggest that overall and cancer-specific survival advantage was most evident in women between 50 and 80 years of age.

Hepatic gene expression patterns following trauma-hemorrhage: effect of posttreatment with estrogen

The aim of this study was to examine the role of estrogen on hepatic gene expression profiles at an early time point following trauma-hemorrhage in rats. Groups of injured and sham controls receiving estrogen or vehicle were killed 2 h after injury and resuscitation, and liver tissue was harvested. Complementary RNA was synthesized from each RNA sample and hybridized to microarrays. A large number of genes were differentially expressed at the 2-h time point in injured animals with or without estrogen treatment. The upregulation or downregulation of a cohort of 14 of these genes was validated by reverse transcription-polymerase chain reaction. This large-scale microarray analysis shows that at the 2-h time point, there is marked alteration in hepatic gene expression following trauma-hemorrhage. However, estrogen treatment attenuated these changes in injured animals. Pathway analysis demonstrated predominant changes in the expression of genes involved in metabolism, immunity, and apoptosis. Upregulation of low-density lipoprotein receptor, protein phosphatase 1, regulatory subunit 3C, ring-finger protein 11, pyroglutamyl-peptidase I, bactericidal/permeability-increasing protein, integrin, αD, BCL2-like 11, leukemia inhibitory factor receptor, ATPase, Cu transporting, α polypeptide, and Mk1 protein was found in estrogen-treated trauma-hemorrhaged animals. Thus, estrogen produces hepatoprotection following trauma-hemorrhage likely via antiapoptosis and improving/restoring metabolism and immunity pathways.

Gender differences in prognosis after esophagectomy for esophageal cancer

PURPOSE

The purpose of this study was to clarify the gender differences in the prognosis, as well as mortality and morbidity, of patients who have undergone esophagectomy for esophageal cancer.

METHODS

The clinical results of esophagectomy were compared between 975 male and 156 female patients with esophageal cancer.

RESULTS

The male to female ratios of cervical and thoracic esophageal cancer were 1.87 and 7.38, respectively (P < 0.01). The incidence of preoperative comorbidities was 32.4 and 17.4 %, respectively, and the rates of both tobacco and alcohol abuse were significantly lower in the females than in the males. The mortality rate was lower in the females (3.8 %) than in the males (5.7 %), although the differences were not significant. The overall survival was significantly better in the female than in the male patients (P = 0.039). The 5- and 10-year overall survival rates were 32.6 and 20.5 % in the males and 39.5 and 32.5 % in the females, respectively. A multivariate analysis revealed gender to be an independent prognostic factor. However, no significant differences were recognized in disease-specific survival.

CONCLUSIONS

These results suggest that the prognosis of females with esophageal cancer is better than that of males after esophagectomy, most likely due to multiple clinical factors, such as a more favorable lifestyle and general status.

Gender different response to immunonutrition in liver cirrhosis with sepsis in rats

Females with sepsis have a better prognosis than males, while those of both genders with cirrhosis have a high mortality. Impaired immunity accompanies liver cirrhosis. The potential association between sex and immunologic response of cirrhotic rats in sepsis following immunonutrition was investigated. One hundred and forty-three rats were randomly divided into groups. Liver cirrhosis was produced by weekly feeding of CCl(4) for 8 weeks. Among them, 24 male and 19 female underwent castration one month before studying. The rats were fed with either immune enhancing diet or control diet for five days, then sepsis was induced with cecal ligation and two holes puncture. Main outcomes included mortality and serum cytokines (IL-1β, 6, and 10). Comparisons were made both within and between genders. Cirrhotic non-castrated male rats showed a significant decrease in mortality (64.1% vs. 32.1%, p = 0.032) with better survival than control diet following immune enhancing diet. Lower mortality of cirrhotic non-castrated female rats was found after immune enhancing diet (69.6% vs. 52.1%, p = 0.365). Cirrhotic castrated male rats showed a lower mortality (44.4%) following immune enhancing diet, and cirrhotic castrated female rats also showed significantly lower mortality and better survival than control diet after immune enhancing diet (87.5% vs. 33.3%, p = 0.004). Plasma concentrations of IL-1β were higher in non-oophorectomized female rats fed with control diet compared to immune enhancing diet. Non-orchidectomized males and non-oophorectomized females exhibited similar increases in IL-10 after immune enhancing diet. Our results demonstrated that immunonutrition was more beneficial for male than female cirrhotic rats following sepsis. Though orchidectomy was not found to be more advantageous for the normal male rats in sepsis, immunonutrition seemed to be as important as sex hormone for female rats in sepsis.

Effects of trauma-hemorrhage and IL-6 deficiency on splenic immune function in a murine trauma model

Splenic immune function is known to be depressed following hemorrhage. The present study investigates the effects of femoral shaft fracture, isolated or in combination with hemorrhage, on early stage cytokine production capacity of splenocytes and observes the role of IL-6 under these conditions. Male IL-6 knockout (IL-6^−/−) and wild-type mice (WT) were randomly divided into three groups: sham (S), isolated femoral fracture (Fx), and femoral fracture + volume controlled hemorrhage (TH-Fx) (n = 6 per group). Animals were sacrificed four hours after induction of hemorrhage and fracture. Cytokine release (TNF-α, IL-6, and IL-10) of isolated and LPS-stimulated splenocytes was determined by cytometric bead array. Femoral fracture with or without hemorrhage caused a suppression of in vitro cytokine production capacity of splenocytes at an early posttraumatic stage in WT and IL-6^−/−. In the absence of IL-6, the profile of splenic cytokine secretion is significantly altered, identifying this cytokine as a potential therapeutic target to modulate the posttraumatic immune response.

Impact of sex and ozone exposure on the course of pneumonia in wild type and SP-A (-/-) mice

Female mice exhibited higher survival rate than males after pneumonia, with a reversal of this pattern following ozone exposure. Surfactant protein A (SP-A) plays an important role in innate immunity and SP-A (-/-) mice were more susceptible to pneumonia than wild type mice. Here, we investigated underlying mechanisms of the differential susceptibility of mice to pneumonia. Wild type and SP-A (-/-) C57BL/6J male and female mice were exposed to ozone or filtered air (FA) and then infected intratracheally with Klebsiella pneumoniae. Blood, spleen, and lung were analyzed for bacterial counts, lung and spleen weights, and sex hormone and cortisol levels were measured in plasma within two days post-infection. We found: 1) in the absence of ozone-induced oxidative stress, males had higher level of bacterial dissemination compared to females; ozone exposure decreased pulmonary clearance in both sexes and ozone-exposed females were more affected than males; 2) ozone exposure increased lung weight, but decreased spleen weight in both sexes, and in both cases ozone-exposed females were affected the most; 3) plasma cortisol levels in infected mice changed: ozone-exposed>FA-exposed, females>males, and infected>non-infected; 4) no major sex hormone differences were observed in the studied conditions; 5) differences between wild type and SP-A (-/-) mice were observed in some of the studied conditions. We concluded that reduced pulmonary clearance, compromised spleen response to infection, and increased cortisol levels in ozone-exposed females, and the higher level of lung bacterial dissemination in FA-exposed males, contribute to the previously observed survival outcomes.

Development and resuscitation of a sedated, mature male miniature swine severe hemorrhage model

BACKGROUND

A sedated, mature male miniature swine hemorrhage model has been specifically developed to evaluate resuscitation products for the Defense Advanced Research Projects Agency Surviving Blood Loss program.

METHODS

Animals were placed in a sling, sedated with midazolam, and hemorrhaged 60% of estimated blood volume (∼39 mL/kg) exponentially for 1 hour with no resuscitation (control; n = 16). An additional 26 swine were treated similarly, then resuscitated with 1 mL/kg/min of Hextend to a systolic blood pressure of either 65 mm Hg ± 2 mm Hg (n = 7) or 80 mm Hg ± 5 mm Hg (n = 7) and with 17β-estradiol (E2) at 1 mg/kg (n = 6) or 10 mg/kg (n = 6). Animals were observed for 3 hours with periodic blood sampling. Survival times for the two E2 groups were not significantly different (p = 0.59); therefore, the groups were combined for comparison with control.

RESULTS

Hemorrhage resulted in a characteristic hypotension and metabolic acidosis. Survival time for the control swine was 64 minutes ± 11.5 minutes with a 6% survival at 180 minutes. The 180 minutes Hextend survival was 86% for 65 mm Hg and 100% for 80 mm Hg. E2 survival was 125 minutes ± 15.3 minutes, significantly different from control (p = 0.01), but E2 survival of 25% at 180 minutes was not different from control.

CONCLUSION

A sedated, sexually mature male miniature swine severe hemorrhage model has been successfully developed, resuscitated with Hextend and used to evaluate E2 as a small volume resuscitation product.

Gender dimorphism in the gut: mucosal protection by estrogen stimulation of IgA transcytosis

BACKGROUND

Laboratory studies demonstrate gender dimorphism following trauma/hemorrhagic shock (T/HS). These differences have been attributed to estrogen (E2) levels. Maintenance of gut barrier function by E2 following T/HS has been recently described. However, the mechanisms are not clear. The principle humoral defense mechanism of the gut is provided by secretory immunoglobulin IgA. It is transported across intestinal epithelial cells (IEC) by a specific transmembrane protein receptor (polyimmunoglobulin receptor, pIgR). Transport of IgA (transcytosis) may be influenced by a number of factors. We postulated that there may be differences in IgA transcytosis and IEC pIgR expression in response to sex hormones. We studied this in vitro.

METHODS

Confluent HT-29 IEC monolayers were established in a two-chamber cell culture system. E2 or dihydrotestosterone (DHT) was added for 72 hours; then dimeric IgA (dIgA) was added to the basal chamber (4°C, to obtain maximal pIgR binding of dIgA). Apical media were sampled at intervals and recovery of secretory immunoglobulin IgA quantitated by enzyme-linked immunosorbent assay. PIgR expression in HT-29 cells was quantitated as mean fluorescence intensity using flow cytometry. Monolayer integrity was confirmed by serial measurement of transepithelial electrical resistance.

RESULTS

IgA transcytosis increased fourfold in 12-hour versus 3-hour culture periods in the control experiments. A similar finding was noted in the DHT experiments on IgA transcytosis. There were dramatic increases in IgA transcytosis across HT-29 cells exposed to E2.This was apparent at both 3- and 12-hour experimental time points and exhibited a dose-response effect. HT-29 cells cocultured with E2 increased pIgR expression in a time- and dose-dependent fashion. The greatest pIgR expression was noted following coculture of HT-29 cells with E2 for 6 days at the 1.0 μmol/L E2 concentration. The integrity of HT-29 monolayers in both the E2 and DHT treatment groups at T = 0 and 72 hours was assessed and showed no significant differences versus control cells.

CONCLUSION

IgA transcytosis was augmented by E2 in a dose-response fashion. This effect was due to augmented intracellular trafficking of IgA and later partly due to increased pIgR expression. The dose-related effects of E2 on IgA transport confirm the findings in animal studies that improved outcomes in females can be related to the estrus cycle.

Does gender impact intensity of care provided to older medical intensive care unit patients?

Introduction. Women receive less aggressive critical care than men based on prior studies. No documented studies evaluate whether men and women are treated equally in the medical intensive care unit (MICU). The Therapeutic Intervention Scoring System-28 (TISS-28) has been used to examine gender differences in mixed ICU studies. However, it has not been used to evaluate equivalence of care in older MICU patients. We hypothesize that given nonsignificant, baseline health differences between genders at MICU admission, the level of care provided would be equivalent. Methods. Prospective cohort of 309 patients ≥60 years old in the MICU of an urban university teaching hospital. Explanatory variables were demographic data and baseline measures. Primary outcomes were TISS-28 scores and MICU interventions. We compare TISS-28 scores by gender using a statistical test of equivalence. Results. Women were older and had more chronic respiratory failure at MICU admission. Using equivalence limits of ±15% on gender-based scores of TISS-28, MICU interventions were equivalent. Supplementary analysis showed no statistically significant association between gender and mortality. Conclusions. In contrast with other reports from the cardiac critical care literature, as measured by the TISS-28, gender-based care delivered to older MICU patients in this cohort was equivalent.

Effects of gender on serum biomarkers of systemic inflammation coincident to experimentally-induced periapical lesions

OBJECTIVE

The literature suggests that females have less adverse effects to infection than males, due to the protective effects of oestrogen. The purpose of our study is to compare the systemic effects of induced periapical lesions between groups of animals with various serum concentrations of oestrogen.

METHODS

To induce periapical inflammation, two molar tooth pulps were exposed in ovariectomized (OVX) and normal female (F) and castrated (Cast-M) and normal male (M) Sprague-Dawley rats (Experimental group, E). Sham-operated control animals from each group were also studied (Control group, C). Twenty-eight days later, serum and maxillas were collected. Serum 17β-oestradiol, testosterone, MMP-9, IL-18, IL-6, TNF-α, and IL-1β concentrations were measured by ELISA. Maxillas were cleaned of residual tissue and digital radiographs were made to verify the presence of periapical lesions. Data were compared by factorial ANOVA, post hoc Tukey, and Pearson correlation tests. Groups were considered to be significantly different when p<0.05.

RESULTS

The serum concentration of IL-18, TNF-α, IL-1-β, IL-6 and MMP-9 was greatest in OVX-E animals, compared to all other groups (p<0.001). F-E rats had significantly higher serum concentrations of these cytokines, compared to F-C. The fold difference in serum concentration of the biomarkers (between E and C groups) was significantly greater in females than males, even though males had higher baseline concentrations of all these biomarkers.

CONCLUSION

When females are oestrogen-deficient, their systemic response to periapical lesions is significantly greater than males, suggesting that oestrogen is essential in protecting females from the effects of this type of inflammation.

Gender Differences in Glucose Variability after Severe Trauma

Gender differences in the physiological response to trauma can affect outcome. Both hyperglycemia and blood glucose (BG) variability predict a poor outcome after trauma. This study examined the hypothesis that both BG levels and the degree of BG variability after trauma are gender-specific and correlate with mortality and morbidity. A retrospective observational cohort study of 1915 trauma patients requiring critical care was performed. Admission BG as well as all BG values obtained during the first week while in the intensive care unit were analyzed. In each patient, the mean BG and the degree of BG variability were calculated. A total of 1560 males and 355 females were studied with an overall mortality rate of 12 per cent. Seventy-six per cent of deaths had a BG greater than 125 mg/dL on admission and as BG variability worsened, the mortality rate also increased. There was a significant difference in male BG variability when comparing survivors with nonsurvivors. Female BG variability did not predict mortality. Failed glucose homeostasis is an important marker of endocrine dysfunction after severe injury. Increased BG variability in males is associated with a higher mortality rate. In females, mortality cannot be predicted based on BG levels or BG variability. These data have significant implications for gender-related differences in postinjury management.

A mouse model of severe halothane hepatitis based on human risk factors

Halothane (2-bromo-2-chloro-1,1,1-trifluoro-ethane) is an inhaled anesthetic that induces severe, idiosyncratic liver injury, i.e., "halothane hepatitis," in approximately 1 in 20,000 human patients. We used known human risk factors (female sex, adult age, and genetics) as well as probable risk factors (fasting and inflammatory stress) to develop a murine model with characteristics of human halothane hepatitis. Female and male BALB/cJ mice treated with halothane developed dose-dependent liver injury within 24 h; however, the liver injury was severe only in females. Livers had extensive centrilobular necrosis, inflammatory cell infiltrate, and steatosis. Fasting rendered mice more sensitive to halothane hepatotoxicity, and 8-week-old female mice were more sensitive than males of the same age or than younger (4-week-old) females. C57BL/6 mice were insensitive to halothane, suggesting a strong genetic predisposition. In halothane-treated females, plasma concentration of tumor necrosis factor-alpha was greater than in males, and neutrophils were recruited to liver more rapidly and to a greater extent. Anti-CD18 serum attenuated halothane-induced liver injury in female mice, suggesting that neutrophil migration, activation, or both are required for injury. Coexposure of halothane-treated male mice to lipopolysaccharide to induce modest inflammatory stress converted their mild hepatotoxic response to a pronounced, female-like response. This is the first animal model of an idiosyncratic adverse drug reaction that is based on human risk factors and produces reproducible, severe hepatitis from halothane exposure with lesions characteristic of human halothane hepatitis. Moreover, these results suggest that a more robust innate immune response underlies the predisposition of female mice to halothane hepatitis.

Gender-based differences in cytokine production after burn injury: a role of interleukin-6

BACKGROUND

Gender-specific differences have been found in the survival of patients after a burn injury. Using a murine model of burn injury, suppression of cell-mediated immunity occurs in a gender-specific manner. Immunosuppression correlated with elevated circulating interleukin-6. This study examines gender differences in cytokine production after injury and the role of interleukin-6.

STUDY DESIGN

A murine model of dorsal scald injury was used to examine differences in splenocyte production of interleukin-2, interleukin-4, and interferon-gamma in male versus female mice, and cytokine production in interleukin-6-deficient male mice.

RESULTS

At 24 hours after burn injury, there was substantially greater suppression of T-helper 1 cytokine production in male mice than in female mice. Interleukin-6-deficient male mice had improved cytokine production relative to wild-type mice.

CONCLUSIONS

Suppression of the cell-mediated immune response in male mice correlated with lower T-helper 1 cytokine production, compared with female mice. Additionally, immune response and cytokine production is improved by interleukin-6 deficiency.

A new survivable damage control model including hypothermia, hemodilution, and liver injury

BACKGROUND

The purpose of this article is to describe a new model of traumatic intra-cavitary hemorrhage in a hypothermic, hemodiluted liver injury model that incorporates damage control principles and allows for survival.

MATERIALS AND METHODS

Twenty swine underwent a standardized 35% blood volume hemorrhage followed by resuscitation. Ten animals sustained nonsurgical and 10 a surgical high-grade liver injury. In the surgical liver injury, damage control gauze packing was performed. No operative treatment was provided for the nonsurgical liver injury, which was designed to test the efficacy of systemic hemostatic agents. After a 15 min treatment phase, the abdominal cavity was closed, with the packing in place for the surgical injury, and all animals were resuscitated. Necropsy was performed at 48 h post-injury.

RESULTS

At the time of liver injury, the animals were hemodiluted and hypothermic. Both injuries caused a 20% drop in the mean arterial pressure from baseline (P<0.001). Comparing baseline thromboelastography results with the results after hemodilution, hypothermia, and liver injury, a hypercoagulopathic state was observed. Mortality was 30% for both types of liver injury. The mean volume of intra-abdominal blood present at autopsy was similar for both types of liver injuries (202 ± 161 mL and 214 ± 203 mL, respectively).

CONCLUSION

A new model of traumatic intra-cavitary hemorrhage in a hypothermic, hemodiluted liver injury model with damage control that allows for survival has been described. The mortality rate of 30% allows for the comparison of therapeutic interventions that may lead to improved survival.

Females have fewer complications and lower mortality following trauma than similarly injured males: a risk adjusted analysis of adults in the National Trauma Data Bank

BACKGROUND

Studies of sexual dimorphism in trauma outcomes suggest that women have a survival advantage compared to equivalently injured men. It is unknown if this gender disparity is mediated by potentially life-threatening complications.

OBJECTIVE

To determine (1) if there is a sex-based differences in the odds of developing inpatient complications after trauma, and (2) if are these complications associated with death among trauma patients.

METHODS

Review of adult trauma patients admitted to hospitals in the National Trauma Data Bank that report complications. Patient and injury severity covariates were adjusted using multiple logistic regression and the independent effect of sex on developing complications and associated mortality was determined.

RESULTS

A total of 681,730 adult patients met the inclusion criteria of hospital admission > or =3 days. Women demonstrated a 21% lower adjusted risk of death compared to males (OR 0.79, 95% CI 0.76-0.83). Females had decreased adjusted odds of developing life-threatening complications including pneumonia, acute respiratory distress syndrome, acute renal failure and pulmonary embolism. However, when compared to males with life-threatening complications, females with complications were found to be at greater risk of dying.

CONCLUSION

This study demonstrates that women are less likely than men to develop inpatient complications, suggesting that the survival advantage among women after traumatic injury may involve a reduced susceptibility to developing life-threatening complications.

Systematic analysis of the salutary effect of estrogen on cardiac performance after trauma-hemorrhage

Although 17beta-estradiol (estrogen) and estrogen receptor (ER) agonist administration after trauma-hemorrhage improves cardiac function, it remains unknown what the optimal estrogen or ER agonist dosage is to elicit this beneficial effect. To study this, the dose-dependent effects of estrogen, propylpyrazole triol (ER-alpha agonist), and diarylpropionitrile (DPN; ER-beta agonist) on heart performance (+dP/dt) were determined in sham rats and in experimental animals at the time of maximal bleedout (MBO) or at 2 h after trauma-hemorrhage. The results showed that estrogen and DPN induced dose-dependent increases in the maximal rate of left ventricular pressure increase (+dP/dt) in all groups, whereas propylpyrazole triol was ineffective at all doses. The maximal dose and the 50% effective dose of DPN were approximately 100-fold lower than those of estrogen. The half-life of estrogen in plasma was approximately 25 min in sham and MBO groups. A positive correlation between the estrogen-induced increase in +dP/dt and survival in MBO rats were observed. These results collectively suggest that the salutary effects of estrogen on cardiac performance are dose-dependent and mediated via ER-beta.

[Influence of gender on stimulated cytokine response in patients with severe sepsis]

AIM

Studies suggest that female mice have lower mortality rates than males after sepsis or trauma-hemorrhage. This study investigated the impact of gender and disease severity on monocyte hyporesponsiveness in severe human sepsis.

METHODS

We prospectively investigated 49 (male n=28, female n=21) consecutive patients with severe sepsis. Tumor necrosis factor-alpha (TNF-alpha) and interleukin-10 (IL-10) were assayed by ELISA in unstimulated whole blood cultures or after stimulation with lipopolysaccharide (LPS; E. coli 0111:B4) or Staph. aureus Cowan strain I (SAC-I) lysate at days 1, 2, 3, 4, and 8 after enrollment. Testosterone and estradiol levels were quantified by electrochemoluminescence immunoassays.

RESULTS

Mortality was similar for males (35.7%) and females (42.9%). While disease severity was also comparable, septic patients showed a substantial suppression in stimulated TNF-alpha response compared to healthy controls who recovered within 8 days in surviving patients. Stimulated cytokine response recovered in female non-surviving patients, while it remained suppressed in non-surviving male patients and was significantly different compared to female non-surviving patients. Testosterone levels were substantially suppressed in male but not female septic patients compared to normal values but did not differ between surviving and non-surviving patients. Estradiol levels were elevated in female and male septic patients. Addition of different concentrations of testosterone and estradiol to whole blood obtained from younger (<35 years old) and older (>60 years old) male as well as from younger (proestrous premenopausal) and older (postmenopausal) female non-septic volunteers revealed no effect on LPS-stimulated TNF-alpha and IL-10 release.

CONCLUSION

Severe sepsis leads to a substantial suppression of stimulated cytokine response. Prolonged suppression may serve as a marker of unfavourable outcome in male but not in female individuals suffering from severe sepsis. Furthermore, our data suggest that gender differences in cellular immunity described for young, sexually mature animals obviously persist in typical postmenopausal intensive care unit patients, although a direct interaction between testosterone or estradiol and LPS-stimulated cytokine response could not be demonstrated.