17α-ethynylestradiol-3-sulfate treatment of severe blood loss in rats

Older females have increased mortality after trauma as compared with younger females and males, associated with increased fibrinolysis

INTRODUCTION

Female sex may provide a survival benefit after trauma, possibly attributable to protective effects of estrogen. This study aimed to compare markers of coagulation between male and female trauma patients across different ages.

METHODS

Secondary analysis of a prospective cohort study that was conducted at six trauma centers. Trauma patients presenting with full trauma team activation were eligible for inclusion. Patients with a penetrating trauma or traumatic brain injury were excluded. Upon hospital arrival, blood was drawn for measurement of endothelial and coagulation markers and for rotational thromboelastometry measurement. Trauma patients were divided into four categories: males younger than 45 years, males 45 years or older, females younger than 45 years, and females 45 years or older. In a sensitivity analysis, patients between 45 and 55 years old were excluded to control for menopausal transitioning. Groups were compared with a Kruskal-Wallis test with Bonferroni correction. A logistic regression was performed to assess whether the independent effect of sex and age on mortality.

RESULTS

A total of 1,345 patients were available for analysis. Compared with the other groups, mortality was highest in females 45 years or older, albeit not independent from injury severity and shock. In the group of females 45 years or older, there was increased fibrinolysis, demonstrated by increased levels of plasmin-antiplasmin complexes with a concomitant decrease in α2-antiplasmin. Also, a modest decrease in coagulation factors II and X was observed. Fibrinogen levels were comparable between groups. The sensitivity analysis in 1,104 patients demonstrated an independent relationship between female sex, age 55 years or older, and mortality. Rotational thromboelastometry profiles did not reflect the changes in coagulation tests.

CONCLUSION

Female trauma patients past their reproductive age have an increased risk of mortality compared with younger females and males, associated with augmented fibrinolysis and clotting factor consumption. Rotational thromboelastometry parameters did not reflect coagulation differences between groups.

LEVEL OF EVIDENCE

Prognostic and Epidemiological; Level III.

Sex disparities in adverse outcomes after surgically managed isolated traumatic spinal injury

BACKGROUND

Traumatic spinal injury (TSI) encompasses a wide range of injuries affecting the spinal cord, nerve roots, bones, and soft tissues that result in pain, impaired mobility, paralysis, and death. There is some evidence suggesting that women may have different physiological responses to traumatic injury compared to men; therefore, this study aimed to investigate if there are any associations between sex and adverse outcomes following surgically managed isolated TSI.

METHODS

Using the 2013-2019 TQIP database, all adult patients with isolated TSI, defined as a spine AIS ≥ 2 with an AIS ≤ 1 in all other body regions, resulting from blunt force trauma requiring spinal surgery, were eligible for inclusion in the study. The association between the sex and in-hospital mortality as well as cardiopulmonary and venothromboembolic complications was determined by calculating the risk ratio (RR) after adjusting for potential confounding using inverse probability weighting.

RESULTS

A total of 43,756 patients were included. After adjusting for potential confounders, female sex was associated with a 37% lower risk of in-hospital mortality [adjusted RR (95% CI): 0.63 (0.57-0.69), p < 0.001], a 27% lower risk of myocardial infarction [adjusted RR (95% CI): 0.73 (0.56-0.95), p = 0.021], a 37% lower risk of cardiac arrest [adjusted RR (95% CI): 0.63 (0.55-0.72), p < 0.001], a 34% lower risk of deep vein thrombosis [adjusted RR (95% CI): 0.66 (0.59-0.74), p < 0.001], a 45% lower risk of pulmonary embolism [adjusted RR (95% CI): 0.55 (0.46-0.65), p < 0.001], a 36% lower risk of acute respiratory distress syndrome [adjusted RR (95% CI): 0.64 (0.54-0.76), p < 0.001], a 34% lower risk of pneumonia [adjusted RR (95% CI): 0.66 (0.60-0.72), p < 0.001], and a 22% lower risk of surgical site infection [adjusted RR (95% CI): 0.78 (0.62-0.98), p < 0.032], compared to male sex.

CONCLUSION

Female sex is associated with a significantly decreased risk of in-hospital mortality as well as cardiopulmonary and venothromboembolic complications following surgical management of traumatic spinal injuries. Further studies are needed to elucidate the cause of these differences.

Assessment of ethynylestradiol-3-sulfate on coagulation, metabolism, and survival in pigs with traumatic hemorrhage

BACKGROUND

The beneficial effects of estrogens on survival from hemorrhage have been suggested in some preclinical models. This study investigated the effects of ethynylestradiol-3-sulfate (EE-3-S) on coagulation, metabolism and survival in pigs following traumatic hemorrhage.

METHODS

Twenty-six pigs were randomized into: normal saline group (NS, n = 10), EE-3-S group (EE-3, n = 11) groups, and no resuscitation group (NR, n = 5). Femur fracture was performed in each pig's left leg, followed by hemorrhage of 55% of estimated blood volume and a 10-minute shock period. Afterward, pigs were resuscitated with a small volume of either NS alone (4 mL/kg) or EE-3-S with NS (1 mL/kg at concentration of 1 mg/mL, plus NS solution of 3 mL/kg). Pigs in NR group were not resuscitated with any fluid. All pigs were then monitored for 6 hours or until death, with hemodynamics and survival times recorded. Blood samples were taken during the study for measurements of oxygen metabolism (oxygen delivery, extraction, and consumption) and coagulation function (using Rotem with Extem reagents).

RESULTS

All baseline measurements were similar among the three groups. In the NS group, femur fracture and hemorrhage immediately reduced mean arterial pressure (MAP, 74 ± 3 mm Hg to 44 ± 4 mm Hg) and increased heart rate (97 ± 5 bpm to 218 ± 14 bpm, both p < 0.05). Similar changes in MAP and heart rate were observed in the EE-3 and NR groups. There were no differences observed in changes of Rotem ® measurements or oxygen metabolism among the groups during the study. At 6 hours, four pigs in NS, four pigs in EE-3-S, and two pigs in the NR group survived to the end of the study. The mean survival times were similar among the NS (212 ± 43 minutes), EE-3 (212 ± 39 minutes), and NR (223 ± 63 minutes) groups ( p = 0.9845).

CONCLUSION

Following severe traumatic hemorrhage, hypotensive resuscitation with EE-3-S did not impact coagulation, metabolism, or survival in pigs.

Age and sex differences in blood product transfusions and mortality in trauma patients at a level I trauma center

Objectives

Hemorrhage is a common complication of trauma. We evaluated age and sex differences in treatment with blood product transfusions and massive transfusions as well as in-hospital mortality following trauma at a Level 1 Trauma Center.

Methods

This cross-sectional study evaluated trauma data from a Level 1 trauma center registry from January 2013 to December 2017. The primary outcome was amount of blood products (packed red blood cells (PRBCs), plasma, platelets), and massive transfusion (MT) by biological sex and by age group: 16-24 (youth), 25-59 (middle age), and >=60 (older age) The secondary outcome was in-hospital mortality to hospital discharge.

Results

There were 13596 trauma patients in the registry, mean age was 48 years, 4589 (34%) female and 9007 (66%) male, and median ISS of 9. Male patients received significantly more PRBC transfusions than female patients within 4-hours 6.6% vs 4.4%, and 24-hours 6.7% vs 4.5% respectively. Older patients received significantly fewer PRBC transfusions within 4-hours and 24-hours than their younger counterparts, with 6.9% in the youth group, 6.8% in the middle age group, and 3.9% in the older group (p<0.001). When adjusted for injury severity, the odds of receiving a blood transfusion within 4 hours of injury was significantly lower in older females. Using multivariate analysis, predictors of mortality included (in order of significance) injury severity, older age, transfusion within 4 hours of injury, penetrating trauma, and male sex.

Conclusion

In this large trauma cohort, older female trauma patients were less likely to receive blood products compared to younger females and to their older male counterparts, even after adjusting for injury severity. Predictors of mortality included injury severity, older age, early transfusion, penetrating trauma, and male sex. Following trauma, older women appear vulnerable to undertreatment. Further study is needed to determine the reasons for these differences and their impact on patient outcomes.

State-of-the-Art Review: Sex Hormone Therapy in Trauma-Hemorrhage

ABSTRACT

Trauma-hemorrhage is the leading cause of prehospital and early in-hospital deaths, while also significantly contributing to the later development of multisystem organ dysfunction/failure and sepsis. Common and advanced resuscitative methods would potentially demonstrate benefits in the prehospital setting; however, they face a variety of barriers to application and implementation. Thus, a dialogue around a novel adjunct has arisen, sex hormone therapy. Proposed candidates include estradiol and its derivatives, metoclopramide hydrochloride/prolactin, dehydroepiandrosterone, and flutamide; with each having demonstrated a range of salutary effects in several animal model studies. Several retrospective analyses have observed a gender-based dimorphism in mortality following trauma-hemorrhage, thus suggesting that estrogens contribute to this pattern. Trauma-hemorrhage animal models have shown estrogens offer protective effects to the cardiovascular, pulmonary, hepatic, gastrointestinal, and immune systems. Additionally, a series of survival studies utilizing 17α-ethinylestradiol-3-sulfate, a potent, water-soluble synthetic estrogen, have demonstrated a significant survival benefit and beneficial effects on cardiovascular function. This review presents the findings of retrospective clinical studies, preclinical animal studies, and discusses how and why 17α-ethinylestradiol-3-sulfate should be considered for investigation within a prospective clinical trial.

An estrogen (17α-ethinyl estradiol-3-sulfate) reduces mortality in a swine model of multiple injuries and hemorrhagic shock

BACKGROUND

Although 17α-ethinyl estradiol-3-sulfate (EES) reduces mortality in animal models of controlled hemorrhage, its role in a clinically relevant injury model is unknown. We assessed the impact of EES in a swine model of multiple injuries and hemorrhage.

METHODS

The study was performed under Good Laboratory Practice, with 30 male uncastrated swine (25-50 kg) subjected to tibial fracture, pulmonary contusion, and 30% controlled hemorrhage for an hour. Animals were randomized to one of five EES doses: 0 (control), 0.3, 1, 3, and 5 mg/kg, administered postinjury. Subjects received no resuscitation and were observed for 6 hours or until death. Survival data were analyzed using Cox-proportional hazard regression. Left ventricular pressure-volume loops were used to derive preload recruitable stroke work as a measure of cardiac inotropy. Immediate postinjury preload recruitable stroke work values were compared with values at 1 hour post-drug administration.

RESULTS

Six-hour survival for the 0, 0.3, 1, 3, and 5 mg/kg groups was 0%, 50%, 33.3%, 16.7%, and 0%, respectively. Following Cox regression, the hazard (95% confidence interval) of death was significantly reduced in the 0.3 (0.22 [0.05-0.93]) and 1 (0.24 [0.06-0.89]) mg/kg groups but not the 3 (0.49 [0.15-1.64]) and 5 (0.46 [0.14-1.47]) mg/kg groups. Mean survival time was significantly extended in the 1 mg/kg group (246 minutes) versus the 0 mg/kg group (96 minutes) (p = 0.04, t test). At 1 hour post-drug administration, inotropy was significantly higher than postinjury values in the 0.3 and 1 mg/kg groups (p = 0.003 and p < 0.001, respectively). Inotropy was unchanged in the 3 and 5 mg/kg groups but significantly depressed in the control (p = 0.022).

CONCLUSION

Administration of EES even in the absence of fluid resuscitation reduces mortality and improves cardiac inotropy in a clinically relevant swine model of multiple injuries and hemorrhage. These findings support the need for a clinical trial in human trauma patients.

17α-Ethinyl estradiol-3-sulfate increases survival and hemodynamic functioning in a large animal model of combined traumatic brain injury and hemorrhagic shock: a randomized control trial

Background

Traumatic brain injury (TBI) and severe blood loss resulting in hemorrhagic shock (HS) represent leading causes of trauma-induced mortality, especially when co-occurring in pre-hospital settings where standard therapies are not readily available. The primary objective of this study was to determine if 17α-ethinyl estradiol-3-sulfate (EE-3-SO4) increases survival, promotes more rapid cardiovascular recovery, or confers neuroprotection relative to Placebo following TBI + HS.

Methods

All methods were approved by required regulatory agencies prior to study initiation. In this fully randomized, blinded preclinical study, eighty (50% females) sexually mature (190.64 ± 21.04 days old; 28.18 ± 2.72 kg) Yucatan swine were used. Sixty-eight animals received a closed-head, accelerative TBI followed by removal of approximately 40% of circulating blood volume. Animals were then intravenously administered EE-3-SO4 formulated in the vehicle at 5.0 mg/mL (dosed at 0.2 mL/kg) or Placebo (0.45% sodium chloride solution) via a continuous pump (0.2 mL/kg over 5 min). Twelve swine were included as uninjured Shams to further characterize model pathology and replicate previous findings. All animals were monitored for up to 5 h in the absence of any other life-saving measures (e.g., mechanical ventilation, fluid resuscitation).

Results

A comparison of Placebo-treated relative to Sham animals indicated evidence of acidosis, decreased arterial pressure, increased heart rate, diffuse axonal injury and blood–brain barrier breach. The percentage of animals surviving to 295 min post-injury was significantly higher for the EE-3-SO4 (28/31; 90.3%) relative to Placebo (24/33; 72.7%) cohort. EE-3-SO4 also restored pulse pressure more rapidly post-drug administration, but did not confer any benefits in terms of shock index. Primary blood-based measurements of neuroinflammation and blood brain breach were also null, whereas secondary measurements of diffuse axonal injury suggested a more rapid return to baseline for the EE-3-SO4 group. Survival status was associated with biological sex (female > male), as well as evidence of increased acidosis and neurotrauma independent of EE-3-SO4 or Placebo administration.

Conclusions

EE-3-SO4 is efficacious in promoting survival and more rapidly restoring cardiovascular homeostasis following polytraumatic injuries in pre-hospital environments (rural and military) in the absence of standard therapies. Poly-therapeutic approaches targeting additional mechanisms (increased hemostasis, oxygen-carrying capacity, etc.) should be considered in future studies.

Ethinyl estradiol sulfate acts without fluid resuscitation through estrogen receptors to rapidly protect the cardiovascular system from severe hemorrhage

BACKGROUND

Our in vivo rodent and pig model evidenced that estrogen and its derivative, ethinyl estradiol sulfate (EES), promote survival following hemorrhagic shock. To determine its mechanism, we first confirmed EES binding to estrogen receptor (ER) and improving/restoring cellular signaling, countering the assumption that EES, an ethinyl estradiol metabolite, is inactive. In addition, we examined if EES acts rapidly, consistent with nongenomic signaling. We selected the biomarkers of cardiovascular performance, reduction of apoptosis and proinflammatory responses, and elaboration of nitric oxide (NO) to validate efficacy.

METHODS

A rat trauma-hemorrhage model, consisting of a midline laparotomy and controlled bleeding (60% blood loss) without fluid resuscitation, was used. At 30 minutes after hemorrhage, heart performance was monitored, and Western blots were used to quantify biochemical analytes. The specificity of EES for ER was profiled with ER antagonists. Binding studies by Sekisui XenoTech (Kansas City, KS) determined an LD50 value for EES binding the rat ER.

RESULTS

The EES IC50 value was 1.52 × 10-8 Mol/L, consistent with pharmacologic efficacy. Ethinyl estradiol sulfate raised mean arterial pressure and ±derivative of pressure over time (dP/dT) significantly (but did not fully restore) within a 30-minute window. Levels of apoptosis and activation of NF-κB were dramatically reduced, as was elaboration of nitric oxide (NO) by inducible nitric oxide synthase. Phospho-endothelial nitric oxide synthase (eNOS) was restored to physiological levels. The restoration of cellular signaling occurs before restoration of cardiac contractility.

CONCLUSION

Ethinyl estradiol sulfate is a potent drug for improving heart performance, which also dramatically reduces damage by apoptosis, proinflammatory activity, and NO production, validating that EES can blunt multiple harmful outcomes arising from hypoxia and hypovolemia. The actions are dependent on receptor engagement, where specificity is confirmed by ER antagonists. The constraint of a 30-minute sampling window affirms that the responses are nongenomic and very likely restricted to cell-surface receptor engagement. The rapidity of these responses makes EES promising for intervention in the "golden hour."

A single dose of estrogen during hemorrhagic shock protects against Kidney Injury whereas estrogen restoration in ovariectomized mice is ineffective

The protective effect of estrogens against chronic glomerular diseases is admitted but remains debated during acute kidney injury (AKI). Using a model of resuscitated hemorrhagic shock in C57/Bl6 female mice, this study evaluated at 1 and 21 days the renal effect of (1) endogenous estrogen, using ovariectomized mice with or without chronic estrogen restoration, or (2) exogenous estrogen, using a single administration of a pharmacological dose during shock resuscitation. In both ovariectomized and intact mice, hemorrhagic shock induced epithelial cell damages (assessed by KIM-1 renal expression) with secondary renal fibrosis but without significant decrease in GFR at day 21. Ovariectomy with or without estrogen restoration have no significant effect on renal damages and dysfunction. This lack of effect was associated with a marked (> 80%) reduction of total kidney GPR30 expression. By contrast, a single high dose of estradiol in intact mice reduced renal KIM-1 expression by 2/3, attenuated the severity of cell death related to pyroptosis, and prevented the increase of fibrosis by 1/3. This provides a rationale to investigate the benefits of a single administration of estrogen or estrogen modulators during acute kidney injuries in males. Furthermore, the cost/benefit ratio of such administration should be investigated in Human.

Pulse Oximeter Plethysmograph Variation During Hemorrhage in Beta-Blocker-Treated Swine

BACKGROUND

Beta-blockers blunt the stress response to hemorrhage. Our aim was to investigate the feasibility of noninvasive pulse oximeter plethysmographic waveform variation (PoPV) for predicting blood volume loss in an esmolol-treated swine hemorrhagic shock model.

MATERIALS AND METHODS

Controlled hemorrhage was induced in eight male domestic pigs. In four pigs, a total of 15% and 30% blood volume was drawn step-by-step over 10 min in each step (controlled hemorrhage-only pigs). In the other four pigs, the heart rate (HR) was reduced and maintained by 30% from baseline by esmolol infusion before controlled hemorrhage (esmolol-treated pigs). Diagnostic abilities of HR, pulse pressure variation (PPV), PoPV, and mean arterial pressure for 15% and 30% blood volume loss were determined by the area under the receiver operating characteristic curve (AUC).

RESULTS

PoPV was well correlated with PPV in controlled hemorrhage-only pigs (r = 0.717) and esmolol-treated pigs (r = 0.532). In controlled hemorrhage-only pigs, HR (AUC = 0.841 and 0.864), PPV (0.878 and 0.843), and PoPV (0.779 and 0.793) accurately predicted 15% and 30% of blood volume loss. In esmolol-treated pigs, the diagnostic ability of HR was decreased (AUC = 0.766 and 0.733). However, diagnostic abilities of PPV (0.848 and 0.804) and PoPV (0.808 and 0.842) were not deteriorated.

CONCLUSIONS

The diagnostic ability of HR for blood volume loss was blunted by esmolol. However, those of PPV and PoPV were not altered. PoPV may be considered to be a useful noninvasive tool to predict blood volume loss in injured patients taking beta-blockers.

Neuroendocrine Modulation of the Immune Response after Trauma and Sepsis: Does It Influence Outcome?

Although the treatment of multiple-injured patients has been improved during the last decades, sepsis and multiple organ failure (MOF) still remain the major cause of death. Following trauma, profound alterations of a large number of physiological systems can be observed that may potentially contribute to the development of sepsis and MOF. This includes alterations of the neuroendocrine and the immune system. A large number of studies focused on posttraumatic changes of the immune system, but the cause of posttraumatic immune disturbance remains to be established. However, an increasing number of data indicate that the bidirectional interaction between the neuroendocrine and the immune system may be an important mechanism involved in the development of sepsis and MOF. The aim of this article is to highlight the current knowledge of the neuroendocrine modulation of the immune system during trauma and sepsis.

Better therapy for combat injury

In modern warfare, therapy for combat injury is a critical issue to improve personnel survival and battle effectiveness. Be limited to the severe circumstance in the distant battlefield, quick and effective treatment cannot be supplied that leads infections, sepsis, multiple organ dysfunction syndrome (MODS) and high mortality. To get a better therapy for combat injury, we summarized several reports that associated with the mechanisms of sepsis and MODS, those published on MMR recently. Chaudry and colleagues reported gender difference in the outcomes of trauma, shock and sepsis. The advantageous outcome in female is due to their hormone milieu. Their accumulating reports indicated estrogen as a beneficial factor for multiple system and organs, including the central nervous system, the cardiopulmonary system, the liver, the kidneys, the immune system, and leads to better survival from sepsis. Thompson et al. reviewed the underlying mechanisms in trauma induced sepsis, which can be concluded as an imbalance of immune response triggered by damage-associated molecular patterns (DAMPs) and other immune modifying agents. They also emphasize immunomodulation as a better therapeutic strategy that might be a potential benefit in regulating the host immune response. Fan et al. have revealed a crucial mechanism underlying lung epithelial and macrophage crosstalk, which involves IL-25 as a mediator. After the injury, lung epithelial secreted IL-25 promotes TNF-α production in macrophage leading to acute lung injury (ALI). In addition to a mountain of cytokines, mitochondrial dysfunction in immune cell is another critical risk factor for immune dysfunction during sepsis. Both morphology and function alterations in mitochondria are closely associated with inadequate ATP production, insufficient metabolism process and overloaded  ROS production, which lead harm to immune cells and other tissues by triggering oxidative stress. All the above reports discussed mechanisms of sepsis induction after trauma and provided evidence to improve better therapy strategies targeting diverse risk factors.

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.

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.

Where's the Leak in Vascular Barriers? A Review

Edema is typically presented as a secondary effect from injury, illness, disease, or medication, and its impact on patient wellness is nested within the underlying etiology. Therefore, it is often thought of more as an amplifier to current preexisting conditions. Edema, however, can be an independent risk factor for patient deterioration. Improper management of edema is costly not only to the patient, but also to treatment and care facilities, as mismanagement of edema results in increased lengths of hospital stay. Direct tissue trauma, disease, or inappropriate resuscitation and/or ventilation strategies result in edema formation through physical disruption and chemical messenger-based structural modifications of the microvascular barrier. Derangements in microvascular barrier function limit tissue oxygenation, nutrient flow, and cellular waste removal. Recent studies have sought to elucidate cellular signaling and structural alterations that result in vascular hyperpermeability in a variety of critical care conditions to include hemorrhage, burn trauma, and sepsis. These studies and many others have highlighted how multiple mechanisms alter paracellular and/or transcellular pathways promoting hyperpermeability. Roles for endothelial glycocalyx, extracellular matrix and basement membrane, vesiculo-vacuolar organelles, cellular junction and cytoskeletal proteins, and vascular pericytes have been described, demonstrating the complexity of microvascular barrier regulation. Understanding these basic mechanisms inside and out of microvessels aid in developing better treatment strategies to mitigate the harmful effects of excessive edema formation.

Hemorrhagic Shock and the Microvasculature

The microvasculature plays a central role in the pathophysiology of hemorrhagic shock and is also involved in arguably all therapeutic attempts to reverse or minimize the adverse consequences of shock. Microvascular studies specific to hemorrhagic shock were reviewed and broadly grouped depending on whether data were obtained on animal or human subjects. Dedicated sections were assigned to microcirculatory changes in specific organs, and major categories of pathophysiological alterations and mechanisms such as oxygen distribution, ischemia, inflammation, glycocalyx changes, vasomotion, endothelial dysfunction, and coagulopathy as well as biomarkers and some therapeutic strategies. Innovative experimental methods were also reviewed for quantitative microcirculatory assessment as it pertains to changes during hemorrhagic shock. The text and figures include representative quantitative microvascular data obtained in various organs and tissues such as skin, muscle, lung, liver, brain, heart, kidney, pancreas, intestines, and mesentery from various species including mice, rats, hamsters, sheep, swine, bats, and humans. Based on reviewed findings, a new integrative conceptual model is presented that includes about 100 systemic and local factors linked to microvessels in hemorrhagic shock. The combination of systemic measures with the understanding of these processes at the microvascular level is fundamental to further develop targeted and personalized interventions that will reduce tissue injury, organ dysfunction, and ultimately mortality due to hemorrhagic shock. Published 2018. Compr Physiol 8:61-101, 2018.

Aromatase Blockade Is Associated With Increased Mortality in Acute Illness in Male Mice

Context:

The increase in circulating estrogen levels with acute illness in humans is accompanied by increased aromatase expression in adipose tissue and increased peripheral aromatization of estrogens to androgens. Animal studies indicate that estrogen may be beneficial in acute illness.

Objective:

We hypothesized that blockade of aromatase in acute illness would decrease survival.

Design:

Prospective sham controlled.

Setting:

Maine Medical Center Research Institute animal facility.

Animals:

Six- to 8-week-old male black 6 mice.

Intervention:

Mice underwent cecal ligation and puncture (CLP) to induce acute illness and were administered letrozole to block aromatase or saline. Mice undergoing sham surgery with or without letrozole served as controls. Adipose and cardiovascular tissue was harvested for preliminary evaluation of aromatase expression.

Main outcome measurements:

Survival was the main outcome measurement. Evidence for aromatase expression in tissue samples was assessed using western blot and/or immunohistochemistry.

Results:

With aromatase blockade, survival in CLP mice was decreased (P = 0.04). The presence of aromatase in adipose tissue was observed by western blot in CLP but not control mice. Similarly, the presence of aromatase was observed in cardiac tissue of CLP but not in control mice.

Conclusions:

The decreased survival during sepsis with aromatase blockade suggests that this response to acute illness may be important both physiologically and clinically. The preliminary observation of aromatase expression in adipose and cardiovascular tissue during acute illness in this mouse model indicates that this model has parallels to human physiology and may be useful for further studying the aromatase response to acute illness.

Treatment of traumatic brain injury with 17α-ethinylestradiol-3-sulfate in a rat model

OBJECTIVE

17α-ethynylestradiol-3-sulfate (EE-3-SO4) is a highly water-soluble synthetic estrogen that has an extended half-life (∼ 10 hours) over that of naturally occurring estrogen (∼ 10 minutes). In this study, EE-3-SO4 was evaluated in a lateral fluid percussion–induced traumatic brain injury (TBI) model in rats.

METHODS

A total of 9 groups of Sprague-Dawley rats underwent craniectomy. Twenty-four hours later, lateral fluid percussion was applied to 6 groups of animals to induce TBI; the remaining 3 groups served as sham control groups. EE-3-SO4 (1 mg/kg body weight in 0.4 ml/kg body weight) or saline (vehicle control) was injected intravenously 1 hour after TBI; saline was injected in all sham animals. One day after EE-3-SO4/saline injection, intracranial pressure (ICP), cerebral perfusion pressure (CPP), and partial brain oxygen pressure (PbtO2) were measured in Groups 1–3 (2 TBI groups and 1 sham group), and brain edema, diffusion axonal injury, and cerebral glycolysis were assessed in Groups 4–6 using MRI T2 mapping, diffusion tensor imaging (DTI), and FDG-PET imaging, respectively. Four days after dosing, the open-field anxiety of animals was assessed in Groups 7–9 by measuring the duration that each animal spent in the center area of an open chamber during 4 minutes of monitoring.

RESULTS

EE-3-SO4 significantly lowered ICP while raising CPP and PbtO2, compared with vehicle treatment in TBI-induced animals (p < 0.05). The mean size of cerebral edema of TBI animals treated with EE-3-SO4 was 25 ± 3 mm3 (mean ± SE), which was significantly smaller than that of vehicle-treated animals (67 ± 6 mm3, p < 0.001). Also, EE-3-SO4 treatment significantly increased the fractional anisotropy of the white matter in the ipsilateral side (p = 0.003) and cerebral glycolysis (p = 0.014). The mean duration that EE-3-SO4-treated animals spent in the center area was 12 ± 2 seconds, which was significantly longer than that of vehicle-treated animals (4 ± 1 seconds; p = 0.008) but not different from that of sham animals (11 ± 3 seconds; p > 0.05).

CONCLUSIONS

These data support the clinical use of EE-3-SO4 for early TBI treatment.