Trauma-hemorrhage induces increased thymic apoptosis while decreasing IL-3 release and increasing GM-CSF

Development of a predictive algorithm for patient survival after traumatic injury using a five analyte blood panel

Severe trauma can induce systemic inflammation but also immunosuppression, which makes understanding the immune response of trauma patients critical for therapeutic development and treatment approaches. By evaluating the levels of 59 proteins in the plasma of 50 healthy volunteers and 1000 trauma patients across five trauma centers in the United States, we identified 6 novel changes in immune proteins after traumatic injury and further new variations by sex, age, trauma type, comorbidities, and developed a new equation for prediction of patient survival. Blood was collected at the time of arrival at Level 1 trauma centers and patients were stratified based on trauma level, tissues injured, and injury types. Trauma patients had significantly upregulated proteins associated with immune activation (IL-23, MIP-5), immunosuppression (IL-10) and pleiotropic cytokines (IL-29, IL-6). A high ratio of IL-29 to IL-10 was identified as a new predictor of survival in less severe patients with ROC area of 0.933. Combining machine learning with statistical modeling we developed an equation ("VIPER") that could predict survival with ROC 0.966 in less severe patients and 0.8873 for all patients from a five analyte panel (IL-6, VEGF-A, IL-21, IL-29, and IL-10). Furthermore, we also identified three increased proteins (MIF, TRAIL, IL-29) and three decreased proteins (IL-7, TPO, IL-8) that were the most important in distinguishing a trauma blood profile. Biologic sex altered phenotype with IL-8 and MIF being lower in healthy women, but higher in female trauma patients when compared to male counterparts. This work identifies new responses to injury that may influence systemic immune dysfunction, serving as targets for therapeutics and immediate clinical benefit in identifying at-risk patients.

Post-shock mesenteric lymph drainage ameliorates cellular immune function in rats following hemorrhagic shock

Disturbance of immunity is an important factor to modulate inflammatory responses after severe shock. Post-shock mesenteric lymph (PSML) return plays an adverse role in multiple organ injuries induced by the hemorrhagic shock, and the inflammatory factors are involved in this process. However, whether the PSML can exacerbate immune dysfunctions that modulate inflammatory response to the hemorrhagic shock remains unknown. In the present study, the effects of PSML drainage on the distribution of T lymphocyte subgroup, the release of inflammatory factors, and apoptosis of thymocytes were investigated; the effect of PSML on the specific parameters of cellular immune function was also determined. Results showed that PSML drainage reduced the increased levels of CD3+, CD3+CD4+, CD4+CD25+ lymphocytes, IFN-γ, and the ratios of CD3 + CD4+/CD3 + CD4- in blood of the shocked rats at 3 h after resuscitation; PSML drainage also abolished the decreased IL-4 level and restored the higher ratio of IFN-γ/IL-4 to normal levels. Tissue injury, including enlarged intermembrance space and edema with congestion in the medulla, increased apoptotic cells and bax expression, decreased number of cells in the S phase, and bcl-2 expression were observed in the thymus after hemorrhagic shock. PSML drainage reversed these effects. In particular, PSML drainage increased the proliferation index and decreased p53 expression of thymocytes. These results suggest that hyperimmunity occurred at early stages of hemorrhagic shock with resuscitation and that PSML drainage could markedly improve cellular immune function that is responsible for the reduced inflammatory responses.

Ultrasound measurement of the transverse diameter of the fetal thymus in pregnancies complicated by the preterm prelabor rupture of membranes

PURPOSE

To determine whether the measurement of the transverse diameter of the fetal thymus is of value in the identification of either histologic chorioamnionitis or funisitis in pregnancies complicated by preterm prelabor rupture of membranes (PPROM).

METHODS

The transverse diameter of the fetal thymus was measured in 216 fetuses from PPROM pregnancies. A small thymus was defined as a transverse thymic diameter below the fifth percentile according to a previously published nomogram. The placenta, the fetal membranes, and the umbilical cord were assessed for the presence of inflammation.

RESULTS

A small thymus was identified in 69% (150/216) of fetuses. A small thymus was present in 80% (106/133) and 88% (36/41) of women with histologic chorioamnionitis or funisitis, respectively. The presence of a small thymus had a sensitivity of 79%, specificity of 47%, positive predictive value of 71%, negative predictive value of 59% for the identification of chorioamnionitis (p < 0.0001; odds ratio 3.5) and a sensitivity of 88%, specificity of 35%, positive predictive value of 24%, and negative predictive value of 92% in the identification of funisitis (p = 0.004; odds ratio 4.4).

CONCLUSIONS

The sonographic finding of a small thymus is a sensitive indicator of histologic chorioamnionitis or funisitis; low specificity excludes it as a possible clinical implication in the management of PPROM pregnancies.

Postoperative immune suppression in visceral surgery: characterisation of an intestinal mouse model

BACKGROUND

Postoperatively acquired immune dysfunction is associated with a higher mortality rate in case of septic complications. As details of this severe clinical problem are still unknown, animal models are essential to characterise the mechanisms involved.

METHODS

Mice were laparotomised and the small intestine was pressed smoothly in antegrade direction. For extension of trauma, the intestine was manipulated three times consecutively. Following this, the ex vivo cytokine release of splenocytes was determined. The degree of surgical trauma was analysed by detection of HMGB1 and IL-6 in serum and by neutrophil staining in the muscularis mucosae.

RESULTS

We adapted the previously described animal model of intestinal manipulation to provide a model of surgically induced immune dysfunction. Following intestinal manipulation, the mice showed elevated serum levels of HMGB1 and IL-6 and increased infiltration of granulocytes into the muscularis mucosae. Ex vivo cytokine release by splenocytes was suppressed in the postoperative period. The degree of suppression correlated with the extent of surgical trauma.

CONCLUSIONS

In this study, we describe a surgically induced immune dysfunction animal model, in which a significant surgical trauma is followed by an immune dysfunction. This model may be ideal for the characterisation of the postoperative immune dysfunction syndrome.

Resuscitation with hydroxyethyl starch solution prevents bone marrow mononuclear apoptosis in a rat trauma-hemorrhagic shock model

BACKGROUND

: Trauma-hemorrhagic shock (T/HS) has been associated with multiorgan dysfunction, including bone marrow failure. This study examined apoptosis and morphologic alterations in bone marrow mononuclear cells (BMMNCs) with different volume therapies after T/HS.

METHODS

: T/HS was induced in groups of male Sprague-Dawley rats through a fracture of the left femur and continual bleeding for 30 minutes, followed by resuscitation with Ringer's lactate solution (RL), 6% hydroxyethyl starch solution (HES), or 5% albumin (ALB). Mean arterial blood pressure was monitored during the T/HS and resuscitation, and the impacts of various resuscitative fluids on apoptosis and morphology of BMMNCs at 24 hours and 48 hours after resuscitation were examined using flow cytometry, transferase-mediated dUTP nick-end labeling assay, and hematoxylin and eosin staining.

RESULTS

: Fluctuations in mean arterial blood pressure were homogenous among the three treatment groups. The percentage of early BMMNC apoptosis increased significantly at 24 hours and 48 hours (24.65% +/- 5.41% and 29.09% +/- 2.07%, respectively; p < 0.05), and the percentage of late BMMNC apoptosis increased to 13.43% +/- 2.82% (p < 0.05) at 48 hours in the T/HS + RL group. In contrast, resuscitation with HES alone dramatically attenuated the apoptosis. Resuscitation with ALB alleviated BMMNC apoptosis, except for late apoptosis at 48 hours. A greater number of apoptotic BMMNCs as well as morphologic alterations were shown using the transferase-mediated dUTP nick-end labeling assay and hematoxylin and eosin stain in the T/HS + RL group than in the HES or ALB groups.

CONCLUSION

: Intravascular volume replacement with HES showed prevention of BMMNC apoptosis at first 48 hours after T/HS compared with RL and ALB. These findings provide new insights into the intervention mechanism of HES on T/HS-related multiorgan dysfunction.

Effect of Intrauterine Exposure of Murine Fetus to Cyclophosphamide on Development of Thymus

The objective of this study was to demonstrate thymic alterations produced by cyclophosphamide intervention during intrauterine life of murine fetus. Cyclophosphamide (CP) was administered to pregnant mice on day 11 of gestation in a single dose of 10 mg/kg body weight. Fetuses were dissected out on day 19 and studied for various effects on thymus. Thymus of fetuses exposed to cyclophosphamide showed thymic atrophy with retardation of thymic size and a remarkable shrinkage in lobular morphology. Histological studies showed a massive depletion of thymic cortex. Study of thymocytes revealed an increase in apoptotic cell count and percent DNA fragmentation along with a decrease in proliferation. Thymocytes obtained from fetuses of CP-treated mice showed a higher expression of caspase-activated DNase (CAD) indicating that the CP-dependent induction of apoptosis in thymocytes involved caspase pathway. The results of the present study may help in understanding the mechanism of the teratogenic effect of cyclophosphamide on thymus.

[Surgical trauma and postoperative immunosuppression]

Abdominal surgery is regularly followed by immune dysfunction that can last for several days. In case of septic complications during this period, there is imminent danger of mortality due to reduced immune function. This fact leads to classification of sepsis in regard to its genesis: spontaneously acquired sepsis type A is distinguishable from sepsis type B, which is acquired postoperatively. The main difference between these types is the immunologic condition at the time point of sepsis development. Postoperative immune dysfunction can be described by several parameters, i.e. reduction of HLA-DR expression on monocytes and increased apoptosis of T lymphocytes. A direct correlation exists between magnitude of immune dysfunction and complexity of the previous surgical trauma. For the first time it is now possible to study this phenomenon of postoperative immune dysfunction by use of an adequate animal model. Intestinal manipulation in mice fulfils the necessary criteria to serve as a model of surgically induced immune dysfunction.

Effect of caspase inhibition on thymic apoptosis in hemorrhagic shock

In hemorrhagic shock (HS) an increased thymic apoptosis (TA) was described. The aim of this study was to evaluate the effect of administration of the caspase inhibitor N-benzyloxy-carbonil-Val-Ala-Asp-fluoromethylketone (Z-VAD-FMK) during the resuscitation phase on TA, organ dysfunctions, and tumor necrosis factor (TNF)-alpha release in HS. Forty rats were randomly assigned to four groups: no HS/resuscitation (sham); HS/resuscitation with shed blood and normal saline (control); HS/resuscitation with shed blood and phosphate-buffered solution (PBS) (vehicle); and HS/resuscitation with shed blood and Z-VAD-FMK (inhibitor). Rats were subjected to HS by blood removal to a MAP of 35-40 mmHg. After a 1-h shock period, the animals were resuscitated according to the protocol. At 1 and 3 h after resuscitation, transaminases, creatinine, urea, lipase, TNF-alpha, and TA were evaluated. Our study showed that a nonlethal HS is early able to induce organ dysfunctions and increased TA. Administration of Z-VAD-FMK did not significantly decrease organ dysfunctions, while it induced a significant TNF-alpha release. TA was significantly reduced by Z-VAD-FMK after 1 h, but not after 3 h. Our results suggest that postinjury caspase inhibition does not attenuate organ dysfunctions, and also does not permanently reduce TA induced by HS and resuscitation in rats.

Biphasic onset of splenic apoptosis following hemorrhagic shock: critical implications for Bax, Bcl-2, and Mcl-1 proteins

Introduction

The innate immune response to trauma hemorrhage involves inflammatory mediators, thus promoting cellular dysfunction as well as cell death in diverse tissues. These effects ultimately bear the risk of post-traumatic complications such as organ dysfunction, multiple organ failure, or adult respiratory distress syndrome. In this study, a murine model of resuscitated hemorrhagic shock (HS) was used to determine the apoptosis in spleen as a marker of cellular injury and reduced immune functions.

Methods

Male C57BL-6 mice were subjected to sham operation or resuscitated HS. At t = 0 hours, t = 24 hours, and t = 72 hours, mice were euthanized and the spleens were removed and evaluated for apoptotic changes via DNA fragmentation, caspase activities, and activation of both extrinsic and intrinsic apoptotic pathways. Spleens from untreated mice were used as control samples.

Results

HS was associated with distinct lymphocytopenia as early as t = 0 hours after hemorrhage without regaining baseline levels within the consecutive 72 hours when compared with sham and control groups. A rapid activation of splenic apoptosis in HS mice was observed at t = 0 hours and t = 72 hours after hemorrhage and predominantly confirmed by increased DNA fragmentation, elevated caspase-3/7, caspase-8, and caspase-9 activities, and enhanced expression of intrinsic mitochondrial proteins. Accordingly, mitochondrial pro-apoptotic Bax and anti-apoptotic Bcl-2 proteins were inversely expressed within the 72-hour observation period, thereby supporting significant pro-apoptotic changes. Solely at t = 24 hours, expression of the anti-apoptotic Mcl-1 protein shows a significant increase when compared with sham-operated and control animals. Furthermore, expression of extrinsic death receptors were only slightly increased.

Conclusion

Our data suggest that HS induces apoptotic changes in spleen through a biphasic caspase-dependent mechanism and imply a detrimental imbalance of pro- and anti-apoptotic mitochondrial proteins Bax, Bcl-2, and Mcl-1, thereby promoting post-traumatic immunosuppression.

Leukocyte apoptosis and its significance in sepsis and shock

Sepsis and multiple organ failure continue to be significant problems among trauma, burn, and the critically ill patient population. Thus, a number of laboratories have focused on understanding the role of altered apoptotic cell death in contributing to immune and organ dysfunction seen in sepsis and shock. Immune cells that undergo altered apoptotic changes include neutrophils, macrophages, dendritic cells, as well as various lymphocyte populations. Evidence of epithelial as well as endothelial cell apoptotic changes has also been reported. Although mediators such as steroids, tumor necrosis factor, nitric oxide, C5a, and Fas ligand (FasL) appear to contribute to the apoptotic changes, their effects are tissue- and cell population-selective. As inhibiting Fas-FasL signaling (e.g., gene deficiency, Fas fusion protein, or Fas short interfering RNA administration), caspase inhibition (caspase mimetic peptides), and/or the overexpression of downstream antiapoptotic molecules (e.g., Bcl-2, Akt) improve survival of septic mice, it not only demonstrates the pathological significance of this process but points to novel targets for the treatment of sepsis.

Hemorrhagic shock induces endothelial cell apoptosis, which is mediated by factors contained in mesenteric lymph

OBJECTIVE

Trauma-hemorrhagic shock is one of the leading causes of acute respiratory distress syndrome. This syndrome is associated with disruption of the alveolar barrier consisting of both epithelial and endothelial cells, which leads to a major increase in epithelial and microvascular permeability in the lungs. Although alveolar epithelial cell apoptosis has been documented as a contributing factor to this increase in permeability, it is unclear whether endothelial cell apoptosis occurs following trauma-hemorrhagic shock and, if so, the source of factors leading to this process.

DESIGN

Prospective animal study with concurrent control.

SETTING

Small-animal laboratory.

SUBJECTS

Adult male Sprague-Dawley rats.

INTERVENTIONS

Trauma-hemorrhagic shock in rats was induced by laparotomy followed by blood withdrawal to achieve a mean arterial blood pressure of 30 mm Hg for 90 mins. At the end of the shock period, the rats were resuscitated, and 3 hrs later lungs were taken for histologic analysis. In other experiments, mesenteric lymph was collected from trauma-hemorrhagic shock and trauma-sham shock rats, and the biological activity of these lymph samples was tested for their ability to kill cultured endothelial cells or endothelial cells of isolated femoral veins.

MEASUREMENTS AND MAIN RESULTS

Trauma-hemorrhagic shock triggered endothelial cell apoptosis in the lung as assessed using the Tunnel assay as well as by light and electron microscopic analysis. Since our previous studies have documented that mesenteric lymph is a major contributor to lung injury following shock, we also tested the hypothesis that factors in the mesenteric lymph were responsible for the endothelial cell apoptosis-inducing effect of shock. Preventing the mesenteric lymph from reaching the lung by mesenteric lymph duct ligation decreased endothelial cell apoptosis. Mesenteric lymph obtained from rats subjected to trauma-hemorrhagic shock elicited apoptosis in cultured endothelial cells and when placed into isolated femoral vein as well as increased endothelial cell monolayer permeability.

CONCLUSIONS

Trauma-hemorrhagic shock induces endothelial as well as epithelial cell apoptosis in the lung via factors contained in the mesenteric lymph, thereby contributing to the pathophysiology of the acute respiratory distress syndrome.

Is thymus redundant after adulthood?

Thymus is considered to involute with age with a decline in thymic function. However, this generality is not universally and incontrovertibly true. Many studies performed in animals and men have proved to the contrary that thymic activity and function appear to be well maintained in the old age and may be indispensable for T cell reconstitution in different immunological settings. During some clinical situations where T cell pool needs to be regenerated, renewal of thymic activity and mass has been observed in an otherwise dormant thymic remnant. New studies have revealed a dynamic interplay between postnatal thymus output and peripheral T cell pool. Moreover, age-related loss of thymic function appears to be only quantitative and not qualitative. This review, thus, focuses on the different conditions that lead to thymic involution and attempts to bring about the emerging notion and the clinical relevance of continuous thymic activity well beyond the adulthood to optimise the function of the immune system in the context of cancer and infectious diseases.

Impact of Shock and Fluid Resuscitation on the Morphology and Apoptosis of Bone Marrow: An Experimental Study

BACKGROUND

We hypothesized that bone marrow failure after hemorrhagic shock might be secondary to impaired apoptosis regulation. Our objective was to assess the morphologic alterations and the rate of apoptosis in bone marrow after hemorrhagic shock and resuscitation.

METHODS

Under pentobarbital anesthesia, Wistar rats (n = 70) underwent femoral vessel cannulation. The hemorrhagic shock model involved a controlled retrieval of blood, maintaining mean blood pressure at 40 +/- 5 mm Hg during 50 minutes. During the resuscitation period, lactated Ringer's (twice the blood volume retrieved, group LR) or NaCl 7.5% (4 mL/kg, group HS) was infused, followed by the previously retrieved blood. Bone marrow was collected through left femoral puncture. Morphology was assessed by Leishmann-stained smears, and apoptosis was assessed through terminal deoxynucleotide transferase-mediated dUTP nick-end labeling assay. Analysis of variance and Tukey's test were applied for statistical treatment, considering p < 0.05 as significant.

RESULTS

LR animals presented a statistically significant decrease in the lymphocytic series (LR, 24.2 +/- 4.2%; Sham, 55.1 +/- 6.6%), together with an increase in the percentage of granulocyte (LR, 51.4% +/- 2.3%; Sham, 31.5 +/- 2.9%) and monocyte precursors (LR, 7.3 +/- 1.3%; Sham, 3.3 +/- 1.1%), detected 72 hours after shock (p < 0.05). Both LR and HS groups presented a significant increase in apoptosis, when compared with the sham group (LR, 13.1 +/- 0.5%; HS, 12.2 +/- 0.7%; Sham, 6.8 +/- 0.4%). The alterations detected in the bone marrow morphology of LR group were not observed in HS animals.

CONCLUSION

There was an increase in bone marrow apoptosis after hemorrhagic shock. The type of resuscitation scheme used did influence bone marrow morphology.

The Role of Oxygen-Free Radical in the Apoptosis of Enterocytes in Scalded Rats After Delayed Resuscitation

BACKGROUND

This study aimed to evaluate the relation between apoptosis of enterocytes and oxygen-free radical injury in scalded rats with delayed resuscitation as well as the role of antioxidants in the prevention of enterocyte apoptosis.

METHODS

For this study, 150 male Wistar rats were divided randomly into four groups representing early resuscitation (ER), delayed resuscitation (DR), N-acetylcysteine (NAC) treatment, and allopurinol (Allo) treatment. The animals were subjected to a 30% total body surface area, full-thickness scald. Fluid therapy was started 6 hours after the injury in the DR and treatment groups. Apoptosis of enterocytes was identified by DNA fragmentation (ap%), DNA agarose gel electrophoresis, and terminal deoxynucleotidyl transferace (TdT)-mediated dUPT-biotin nick end labeling (TUNEL). The contents of malondialdehyde (MDA), total sulfhydryl (TSH), and nonprotein sulfhydryl (NPSH) and the activity of xanthine oxidase in intestinal mucosa were determined after the burn in the four groups.

RESULTS

Apoptosis of enterocytes increased significantly in all the groups. The animals in the DR group showed an earlier and greater increase in ap% than the animals in the ER group. Similar results were seen for electrophoresis, TUNEL assay, and levels of MDA, xanthine oxidase (XO), TSH, and NPSH. Treatment with NAC was associated with a decrease in ap% and MDA, but not XO, as compared with the levels in the DR group, whereas treatment with Allo was associated with a decrease in MDA and XO, but not ap%. Delayed resuscitation was associated with significant decreases in TSH and NPSH, as compared with the levels in the ER group, whereas both the NAC and Allo groups had significantly higher levels of TSH and NPSH than the DR group.

CONCLUSIONS

Significant apoptosis of enterocytes was induced by oxidative stress in the intestinal mucosa after a burn in rats. The findings show that NAC blunted intestinal apoptosis induced by oxygen-free radical, which was generated in the process of ischemia-reperfusion injury after a burn because of delayed resuscitation.

Oral Health and Care in the Intensive Care Unit: State of the Science

Oral health is influenced by oral microbial flora, which are concentrated in dental plaque. Dental plaque provides a microhabitat for organisms and an opportunity for adherence of the organisms to either the tooth surface or other microorganisms. In critically ill patients, potential pathogens can be cultured from the oral cavity. These microorganisms in the mouth can translocate and colonize the lung, resulting in ventilator-associated pneumonia. The importance of oral care in the intensive care unit has been noted in the literature, but little research is available on mechanical or pharmacological approaches to reducing oral microbial flora via oral care in critically ill adults. Most research in oral care has been directed toward patients’ comfort; the microbiological and physiological effects of tooth brushing in the intensive care unit have not been reported. Although 2 studies indicated reductions in rates of ventilator-associated pneumonia in cardiac surgery patients who received chlorhexidine before intubation and postoperatively, the effects of chlorhexidine in reducing ventilator-associated pneumonia in other populations of critically ill patients or its effect when treatment with the agent initiated after intubation have not been reported. In addition, no evaluation of the effectiveness of pharmacological and mechanical interventions relative to each other or in combination has been published. Additional studies are needed to develop and test best practices for oral care in critically ill patients.

Caspase inhibition does not protect against liver damage in hemorrhagic shock

This study was aimed to determine whether administration of an inhibitor of caspase-3 protects hepatocellular function in rats with hemorrhagic shock and whether caspases are important pharmacological targets in attenuating liver injury induced by hemorrhagic shock and resuscitation. Male adult rats were subjected to hemorrhagic shock by bleeding to a mean arterial blood pressure of 35-40 mmHg for 1 h and were then resuscitation with 60% shed blood and lactated Ringers solution. A subgroup of animals was injected i.v. with 2 mg/kg caspase inhibitor, Z-DEVD-FMK, prior to blood withdrawal. Fas ligand expression was markedly elevated and caspase-3 activity increased by 3-fold in hemorrhagic untreated rats. The increase in caspase-3 activity was prevented by administration of Z-DEVD-FMK prior to shock and resuscitation. Poly (adenosine diphosphate ribose) polymerase proteolysis was reduced in rats treated with the caspase-3 inhibitor compared with hemorrhagic untreated animals. Plasma aspartate aminotransferase and alanine aminotransferase values showed a significant increase at 6 h of shock in untreated animals (+360% and +515% as compared with sham-operated animals, respectively). Administration of the caspase-3 inhibitor did not prevent the increase in plasma transaminases. The cytosolic concentration of thiobarbituric acid-reactive substances (TBARS) and the oxidized:reduced glutathione ratio increased in the animals with hemorrhagic shock (+94% and +170%, respectively). These parameters were not significantly modified by pretreatment with Z-DEVD-FMK. It appears that caspase inhibition does not attenuate hepatocellular depression and liver injury induced by hemorrhagic shock and resuscitation.

The influence of apoptosis of mucosal epithelial cells on intestinal barrier integrity after scald in rats

OBJECTIVE

To study the influence of apoptosis of intestinal epithelial cells occurring as a result of reperfusion after burn shock on the intestinal barrier.

METHODS

Fifty Wistar rats were subjected to a 30% TBSA full thickness burn, and normal saline (40 ml/kg) was given intraperitoneally immediately after the injury (group A). Ten rats served as a sham control group. The experimental group B consisted of 50 rats with identical injuries, but the normal saline was not given until 6h after the injury. Apoptosis of intestinal epithelial cells was verified by DNA fragmentation, DNA agarose gel electrophoresis, TUNEL and electron microscope (EM), and DNA fragmentation rate was expressed as ap%. The D-lactic acid in portal vein blood and intestinal diamine oxidase (DAO) were determined to evaluate the permeability and integrity of intestinal mucosal epithelium.

RESULTS

The ap% of intestinal epithelium group B was higher than in that of group A (P<0.05 or 0.01), and its amplitude peaked at 12h for both groups. Typical DNA ladder pattern was seen in electrophoresis in both groups. Apoptotic cells were discerned on the tips of the ileal villi at 3h postscald by TUNEL and EM in the group B, and they appeared earlier than in the group A. There was a significant positive correlation between the ap% and the level of D-lactic acid (group A: r=0.817, P<0.05; group B: r=0.727, P<0.05). On the other hand, a significant negative correlation was found between the ap% and the DAO values (group A: r=-0.937, P<0.01; group B: r=-0.836, P<0.05).

CONCLUSION

Apoptosis occurred in enterocytes after scald injury this pathological change might contribute to a breach of integrity of intestinal epithelium, leading to a compromise in its barrier function. Delayed fluid resuscitation might lead to an earlier and higher degree of apoptosis of the intestinal epithelial cells.

Influence of beta-adrenoceptor antagonists on hemorrhage-induced cellular immune suppression

Hemorrhagic shock is associated with increasing catecholamine plasma concentrations. Plasma catecholamines are known to affect cellular immune functions. We therefore, investigated the effect of endogenously released catecholamines on lymphocyte distribution (CD4+ lymphocytes, CD8+ lymphocytes, and natural killer (NK) cells), splenocyte apoptosis (Annexin V binding), tumor necrosis factor-alpha (TNF-alpha), and interleukin 10 (IL-10) release during a volume-controlled hemorrhagic shock in mice. Mice received either saline (HEM), the non-selective beta-adrenoceptor antagonist propranolol (PROP; 2 mg/kg i.p.), or the beta1-adrenoceptor antagonist metoprolol (MET; 2 mg/kg i.p.) before induction of hemorrhage. Mice were sacrificed to obtain the spleen and whole blood 1 h after hemorrhage, 1 h after fluid resuscitation, and 24 h after hemorrhage. Flow cytometric analysis revealed an increase in circulating NK cells in the HEM group. This effect was completely abolished by pretreatment with propranolol or metoprolol. Furthermore, administration of either beta-adrenoceptor antagonist led to a decrease of circulating CD8+ lymphocyte numbers. Monitoring of splenocyte apoptosis by determination of Annexin V binding revealed an increase in splenocyte apoptosis 24 h after hemorrhage in the HEM group but not in the animals pretreated with propranolol or metoprolol. Induction of hemorrhage did not affect TNF-alpha or IL-10 plasma concentrations in either experimental group. We conclude that plasma catecholamines affect cellular immunity in the early phase of trauma via a beta-adrenergic pathway.

Resuscitation-induced pulmonary apoptosis and intracellular adhesion molecule-1 expression in rats are attenuated by the use of Ketone Ringer's solution

BACKGROUND

Resuscitation with Lactated Ringer's solution after hemorrhagic shock in rats has been shown to cause early cellular injury in the lung. We hypothesized that the use of energy substrates, such as ketone bodies, in the resuscitation fluids would protect against this injury. As markers of cellular injury we measured the induction of apoptotic cell death and the expression of Intracellular Adhesion Molecule-1 (ICAM-1).

STUDY DESIGN

Male Sprague Dawley rats (n = 35) under inhaled isoflurane anesthesia had placement of femoral arterial and venous catheters. A three-stage hemorrhage model was used for this experiment. There was an initial hemorrhage of 27 mL/kg for 10 minutes. During the next 75 minutes another 8 mL/kg of blood was withdrawn at a steady rate. The resuscitation fluids were then infused for 45 minutes during which the third continuous hemorrhage of 8 mL/kg was performed. The animals were randomized to five groups: 1) sham hemorrhage (n = 6); 2) sham resuscitation (n = 7); 3) Lactated Ringer's resuscitation, three times the volume of shed blood (n = 8); 4) Ketone Ringer's (containing 28 mEq/L of beta-hydroxybutyrate) resuscitation, three times the volume of shed blood (n = 7); and 5) plasma resuscitation, volume equal to shed blood (n = 7). The animals were sacrificed 1 hour after resuscitation and lungs were harvested. Western blot technique was used for the determination of proapoptotic protein (bax), antiapoptotic protein (bcl-2), apoptotic fragments of poly ADP-ribose polymerase, and ICAM-1. Sections of lung were also subjected to immunostaining using antibodies to bax and ICAM-1 proteins (reported as number of positive cells/mm2).

RESULTS

Lactated Ringer's resuscitation caused a significant increase in pulmonary apoptosis and ICAM-1 expression compared with the sham hemorrhage group. Animals resuscitated with Ketone Ringer's solution and plasma did not show this injury pattern.

CONCLUSIONS

Substitution of lactate with ketone bodies in the resuscitation fluid attenuates the expression of cellular injury markers in the lung.

Thymic stress in artificially reared and maternally reared rat pups

It is well documented that the hypothalamic-pituitary-adrenal (HPA) axis influences immunological responses to stress. Maternal factors have been shown to be necessary for appropriate modulation of the HPA axis in the developing rat. The purpose of this study was to determine whether artificially reared (AR) infant rat pups (a procedure whereby infant rats are gastrostomized and reared independently of maternal factors) have an altered function of the HPA axis in terms of thymocyte apoptosis (programmed cell death) and other indices of thymic stress. AR and maternally reared (MR) Long-Evans rat pups were randomized to control, fasted, stressed, and fasted+stressed treatment groups, as well as an unhandled, MR naive group that served as a baseline control. AR rat pups were significantly heavier than MR (p<0.001). AR rat pups had significantly lighter thymuses than did the MR pups (p<0.001) and fasted pups had significantly lighter thymuses than unfasted pups, regardless of whether they were in the AR or MR condition (p<0.005). AR pups had significantly lower thymic cell numbers and a greater percent of necrotic cells than did MR pups. There were no significant effects of rearing condition on the percent of apoptotic thymocytes. The thymocyte alterations observed in this study between the two rearing conditions suggest that AR reduces thymic weight and cell numbers, which may have consequences for the development of adult cellular immunity.

Lactated ringer's solution and hetastarch but not plasma resuscitation after rat hemorrhagic shock is associated with immediate lung apoptosis by the up-regulation of the Bax protein

BACKGROUND

We previously demonstrated that the type of resuscitation fluid used in hemorrhagic shock affects apoptosis. Unlike crystalloid, whole blood seems to attenuate programmed cell death. The purpose of this study was to determine whether the acellular components of whole blood (plasma, albumin) attenuated apoptosis and to determine whether this process involved the Bax protein pathway.

METHODS

Rats were hemorrhaged 27.5 mL/kg, kept in hypovolemic shock for 75 minutes, then resuscitated over 1 hour (n = 44). Control animals underwent anesthesia only (sham, n = 7). Treatment animals were bled then randomly assigned to the following resuscitation groups: no resuscitation (n = 6), whole blood (n = 6), plasma (n = 6), 5% human albumin (n = 6), 6% hetastarch (n = 7), and lactated Ringer's solution (LR, n = 6). Hetastarch was used to control for any colloid effect. LR was used as positive control. Immediately after resuscitation, the lung was collected and evaluated for apoptosis by using two methods. TUNEL stain was used to determine general DNA damage, and Bax protein was used to specifically determine intrinsic pathway involvement.

RESULTS

LR and hetastarch treatment resulted in significantly increased apoptosis in the lung as determined by both TUNEL and Bax expression (p < 0.05). Plasma infusion resulted in significantly less apoptosis than LR and hetastarch resuscitation. Multiple cell types (epithelium, endothelium, smooth muscle, monocytes) underwent apoptosis in the lung as demonstrated by the TUNEL stain, whereas Bax expression was limited to cells residing in the perivascular and peribronchial spaces.

CONCLUSION

Apoptosis after volume resuscitation of hemorrhagic shock can be affected by the type of resuscitation fluid used. Manufactured fluids such as lactated Ringer's solution and 6% hetastarch resuscitation resulted in the highest degree of lung apoptosis. The plasma component of whole blood resulted in the least apoptosis. The process of apoptosis after hemorrhagic shock resuscitation involves the Bax protein.

Interleukin-3 and stress

The importance of cytokines as mediators in numerous physiologic and pathologic processes became apparent in the early seventies. In a relatively short period of time the number of characterized and functionally defined interleukins increased rapidly. Concomitantly, the understanding of their role in various important reactions in different systems of the organism in general, and in the interaction between the immune, central nervous and neuroendocrine systems in particular increased. IL-3 is one of the cytokines of great significance for hematopoiesis. In addition, it was shown that interleukin-3 (IL-3) participates in the response of the organism to various types of stress. Surprisingly enough, the reports on its production and activation during or following stress are rather scarce. Therefore, the purpose of this review is to try and compile the information on IL-3 and its role in different types of stress, and also to contribute our own modest experience on the subject.

Effects of hypoxia on granulocytic-monocytic progenitors in rats. Role of bone marrow stroma

Hemorrhagic shock leads to hypoxia and is associated with bone marrow (BM) failure. Hemorrhagic shock is also a predisposing factor in immune dysregulation. Since the BM is the major organ of immune cells in the adult, its failure following hemorrhagic shock may explain the increased susceptibility to infection. The in vitro evidence indicates that hypoxia mediates altered functions in BM stroma. Since similar hematopoietic alterations are reported in hypoxia and hemorrhagic shock, hypoxia alone could be a representative model to study BM responses during hemorrhagic shock. In this study, we use an animal model to dissect the hematopoietic effects of hypoxia. We subjected rats to hypoxia, and at days 1 and 5 post-hypoxia we determined the numbers of granulocytic-monocytic progenitors (CFU-GM) in the BM. We found significant increase (P < 0.05) in CFU-GM at day 1 and a downward trend by day 5. Enhanced BM cellularity could not explain the increase in CFU-GM by day 1. BM stromal cells mediated most of the stimulatory effects by hypoxia. CFU-GM was inversely proportional to bioactive TGF-beta and directly proportional to IL-1. Compared to normoxic rats, IL-6 production was suppressed in BM cells from hypoxic rats. The results show that hypoxia alone initiate a stimulatory response in CFU-GM progenitors. These effects are at least partially mediated through the BM stroma. In the absence of a second insult, CFU-GM reverts to baseline. The data also suggest that hypoxia mediates complex responses that include cytokine production. These results add to the current understanding of hematopoietic responses by hypoxia and adds to the mechanisms of immune dysfunctions following hemorrhagic shock.

Resuscitation with lactated Ringer's solution in rats with hemorrhagic shock induces immediate apoptosis

BACKGROUND

We hypothesize that different resuscitative fluids may immediately affect the degree of apoptosis after hemorrhagic shock.

METHODS

Rats (n = 35) were hemorrhaged 27 mL/kg over 5 minutes followed by 1 hour of shock, then resuscitation over 1 hour. The six treatment groups were sham hemorrhage, sham resuscitation, whole blood resuscitation, lactated Ringer's solution (LR) resuscitation with three times the volume bled, sham hemorrhage with LR infusion, and 7.5% hypertonic saline resuscitation (9.7 mL/kg). Liver and small intestine were harvested immediately after resuscitation. Apoptosis was evaluated by using in situ cell death detection method.

RESULTS

Resuscitation with LR resulted in a significant increase in small intestinal and liver apoptosis. Animals that received LR infusion without hemorrhage had an increased level of apoptosis in the intestine. Apoptosis in the intestine was observed in both the mucosa and muscularis externa. There was no increase in apoptosis in either organ in the animals resuscitated with sham resuscitation, whole blood, and hypertonic saline compared with the sham hemorrhage group.

CONCLUSION

Resuscitation with LR solution after hemorrhagic shock increased immediate cell death by apoptosis in both the small intestine and liver. There was no significant increase in apoptosis in the animals resuscitated with hypertonic saline, whole blood, or in unresuscitated animals. Thus, the type of resuscitation fluid used may affect the apoptotic cellular response to shock.