RESUSCITATION WITH HYDROXYETHYL STARCH SOLUTION PREVENTS NUCLEAR FACTOR κB ACTIVATION AND OXIDATIVE STRESS AFTER HEMORRHAGIC SHOCK AND RESUSCITATION IN RATS

Biomarkers of Coagulation and Inflammation in Dogs after Randomized Administration of 6% Hydroxyethyl Starch 130/0.4 or Hartmann's Solution

Synthetic colloid fluids containing hydroxyethyl starch (HES) have been associated with impairment of coagulation in dogs. It is unknown if HES causes coagulation impairment in dogs with naturally occurring critical illness. This study used banked plasma samples from a blinded, randomized clinical trial comparing HES and balanced isotonic crystalloid for bolus fluid therapy in 39 critically ill dogs. Blood was collected prior to fluid administration and 6, 12, and 24 h thereafter. Coagulation biomarkers measured at each time point included prothrombin time, activated partial thromboplastin time, thrombin time, fibrinogen concentration, and the activities of coagulation factors V, VII, VIII, IX, and X, von Willebrand factor antigen, antithrombin, and protein C. Given the links between coagulation and inflammation, cytokine concentrations were also measured, including interleukins 6, 8, 10, and 18, keratinocyte-derived chemokine, and monocyte chemoattractant protein-1. Data were analyzed with linear mixed effects models. No significant treatment-by-time interactions were found for any biomarker, indicating that the pattern of change over time was not modified by treatment. Examining the main effect of time showed significant changes in several coagulation biomarkers and keratinocyte-derived chemokines. This study could not detect evidence of coagulation impairment with HES.

The Beneficial Effect of HES on Vascular Permeability and Its Relationship With Endothelial Glycocalyx and Intercellular Junction After Hemorrhagic Shock

Background

Vascular leakage is a common complication of hemorrhagic shock. Endothelial glycocalyx plays a crucial role in the protection of vascular endothelial barrier function. Hydroxyethyl starch (HES) is a commonly used resuscitation fluid for hemorrhagic shock. However, whether the protective effect of HES on vascular permeability after hemorrhagic shock is associated with the endothelial glycocalyx is unclear.

Methods

Using hemorrhagic shock rat model and hypoxia treated vascular endothelial cells (VECs), effects of HES (130/0.4) on pulmonary vascular permeability and the relationship to endothelial glycocalyx were observed.

Results

Pulmonary vascular permeability was significantly increased after hemorrhagic shock, as evidenced by the increased permeability of pulmonary vessels to albumin-fluorescein isothiocyanate conjugate (FITC-BSA) and Evans blue, the decreased transendothelial electrical resistance of VECs and the increased transmittance of FITC-BSA. The structure of the endothelial glycocalyx was destroyed, showing a decrease in thickness. The expression of heparan sulfate, hyaluronic acid, and chondroitin sulfate, the components of the endothelial glycocalyx, was significantly decreased. HES (130/0.4) significantly improved the vascular barrier function, recovered the thickness and the expression of components of the endothelial glycocalyx by down-regulating the expression of heparinase, hyaluronidase, and neuraminidase, and meanwhile increased the expression of intercellular junction proteins ZO-1, occludin, and VE-cadherin. Degradation of endothelial glycocalyx with degrading enzyme (heparinase, hyaluronidase, and neuraminidase) abolished the beneficial effect of HES on vascular permeability, but had no significant effect on the recovery of the expression of endothelial intercellular junction proteins induced by HES (130/0.4). HES (130/0.4) decreased the expression of cleaved-caspase-3 induced by hemorrhagic shock.

Conclusions

HES (130/0.4) has protective effect on vascular barrier function after hemorrgic shock.The mechanism is mainly related to the protective effect of HES on endothelial glycocalyx and intercellular junction proteins. The protective effect of HES on endothelial glycocalyx was associated with the down-regulated expression of heparinase, hyaluronidase, and neuraminidase. HES (130/0.4) had an anti-apoptotic effect in hemorrhagic shock.

Lactated Ringer' Solution may be Superior to Saline-Based 6% Hydroxyethyl Starch 130/0.4 for Early Resuscitation within 12 hours from Hemorrhagic Shock

Purpose: To compare the effects of fluid resuscitation with lactated Ringer's solution (LR) and saline-based 6% hydroxyethyl starch 130/0.4 (HES) on the inflammatory response and oxidative stress in the small intestine as well as on bacterial translocation to the liver. Methods: Sprague-Dawley rats were subjected to blood pressure-controlled hemorrhagic shock and then resuscitated with LR or HES. At 1, 3, 6, 12, and 24 hr after resuscitation, liver tissues were collected to count the bacterial colonies, and small intestines were harvested to analyze the levels of inflammatory (TNF-α and HO-1) and oxidative stress (MPO) mediators as well as the intestinal injury by immunohistochemistry, colorimetry and hematoxylin & eosin staining, respectively. Results: The expression level of TNF-α in the LR group was stable from 1 to 6 hr but decreased at 12 hr and then abruptly increased at 24 hr. The expression level of TNF-α in the LR group was significantly lower than that in the HES group, especially during the first 12 hr post-fluid infusion. MPO activity decreased to its lowest level at 3 hr but increased from 6 to 12 hr, with no difference at 24 hr between the two groups. Although a decreasing tendency was observed from 6 hr, HO-1 expression levels remained higher in the LR group than in the HES group at 12 and 24 hr, particularly at 12 hr. During the initial 12 hr, the LR group exhibited significantly lower colony-forming units in the liver tissues than the HES group. Chiu's score in the intestine decreased regardless of which resuscitative fluids were used. Conclusions: During early resuscitation (within 12 hr), LR may be superior to HES in reducing intestinal injuries by suppressing inflammatory and oxidative mediators.

Sodium tanshinone IIA sulfonate attenuates hemorrhagic shock-induced organ damages by nuclear factor-kappa B pathway

BACKGROUND

Trauma resulted hemorrhagic shock (HS) leads to increased oxidative stress and inflammatory responses, which contributes greatly to organ failure or dysfunction. Tanshinone IIA sulfonate (TSA), as an antioxidant, may potentially be used in fluid resuscitation to prevent HS-induced organ damages.

METHODS

In this study, a rat HS model was constructed. HS rats received TSA or vehicle drug during resuscitation. Mean arterial pressure and factors associated with organ failure or dysfunction, oxidative stress, and inflammatory response were investigated to evaluate treatment responses. Expression of proteins in NF-кB pathway was evaluated to elucidate the mechanism of TSA in preventing HS-induced organ damage.

RESULTS

Although HS induced organ damage and upregulated oxidative stress and inflammatory response, TSA treatment ameliorated organ dysfunction, reduced oxidative stress, and suppressed inflammatory responses. We also showed that TSA treatment attenuated HS-induced activation in NF-кB pathway.

CONCLUSIONS

TSA can potentially serve as an antioxidant for ameliorating HS-induced organ failure or function. Its mechanism of action may be through inhibiting NF-кB pathway.

Effects of terlipressin as early treatment for protection of brain in a model of haemorrhagic shock

Introduction

We investigated whether treatment with terlipressin during recovery from hypotension due to haemorrhagic shock (HS) is effective in restoring cerebral perfusion pressure (CPP) and brain tissue markers of water balance, oxidative stress and apoptosis.

Methods

In this randomised controlled study, animals undergoing HS (target mean arterial pressure (MAP) 40 mmHg for 30 minutes) were randomised to receive lactated Ringer’s solution (LR group; n =14; volume equal to three times the volume bled), terlipressin (TERLI group; n =14; 2-mg bolus), no treatment (HAEMO group; n =12) or sham (n =6). CPP, systemic haemodynamics (thermodilution technique) and blood gas analyses were registered at baseline, shock and 5, 30, 60 (T60), 90 and 120 minutes after treatment (T120). After the animals were killed, brain tissue samples were obtained to measure markers of water balance (aquaporin-4 (AQP4)), Na⁺-K⁺-2Cl⁻ co-transporter (NKCC1)), oxidative stress (thiobarbituric acid reactive substances (TBARS) and manganese superoxide dismutase (MnSOD)) and apoptotic damage (Bcl-x and Bax).

Results

Despite the HS-induced decrease in cardiac output (CO) and hyperlactataemia, resuscitation with terlipressin recovered MAP and resulted in restoration of CPP and in cerebral protection expressed by normalisation of AQP4, NKCC1, TBARS and MnSOD expression and Bcl-x/Bax ratio at T60 and T120 compared with sham animals. In the LR group, CO and blood lactate levels were recovered, but the CPP and MAP were significantly decreased and TBARS levels and AQP4, NKCC1 and MnSOD expression and Bcl-x/Bax ratio were significantly increased at T60 and T120 compared with the sham group.

Conclusions

During recovery from HS-induced hypotension, terlipressin was effective in normalising CPP and cerebral markers of water balance, oxidative damage and apoptosis. The role of this pressor agent on brain perfusion in HS requires further investigation.

Prognostic indicators after cardiac surgery in children and their relationship with the oxidative stress response

OBJECTIVES

To analyse the trend in lipid peroxidation and antioxidant response as key markers of oxidative stress after paediatric cardiovascular surgery, and compare them with other internationally accepted clinical prognostic indicators.

PATIENTS AND METHODS

A prospective study was conducted on 30 children aged one month to 14 years, weight>5 kg, undergoing cardiopulmonary bypass surgery. Blood samples were taken just before the intervention, immediately after surgery, and after 18-20 h. Cell membrane lipid peroxidation was analysed by quantifying malondialdehyde, as well as measuring total glutathione (oxidized and reduced), as representatives of antioxidant response. An analysis was also performed on clinical variables for establishing a score for the systemic inflammatory response syndrome associated with cardiopulmonary bypass.

RESULTS

The study included 30 children with a mean age of 4.1 years old (interquartile range [IQR]: 2.7; 8.0). Of these, 62.1% were girls. The standard deviation of the median weight was -0.39 (IQR: -0.76; 0.24), the median height was -0.22 (IQR: -0.74; 0.27), and the median BMI was -0.43 (IQR: -1; 0.45). The final surgery times were divided into 2 parts: total time of extracorporeal circulation, with a mean of 79 min (IQR: 52.5; 125.5), and the clamping time, a measurement included in the previous figure with a mean value of 38.5 min (IQR: 22; 59). Malondialdehyde increased and glutathione decreased in postoperative time, with clear, statistically significant direct correlation between time of extracorporeal circulation and percentage decrease in total glutathione between preoperative and immediate postoperative time, and a decline between the preoperative and late postoperative. There was a statistical correlation between total glutathione levels at 18-20 h postoperatively and the duration of mechanical ventilation and inflammatory systemic response syndrome.

CONCLUSIONS

Surgery with extracorporeal circulation performed in children activates inflammatory mediators, being maximum after aortic clamping, and improving after the first 24h. The level of oxidative stress activation depends on surgical times. The development of systemic inflammatory response syndrome is associated with longer duration of mechanical ventilation, longer stay in intensive care, higher scores in the Aristotle model and longer surgical times. Those who do not meet criteria for inflammatory response have higher levels of glutathione in first 24h.

Treadmill exercise activates Nrf2 antioxidant system to protect the nigrostriatal dopaminergic neurons from MPP+ toxicity

Exercise induces oxidative stress, which may activate adaptive antioxidant responses. Nuclear factor erythroid 2-related factor 2 (Nrf2) plays an important role in the defense of oxidative stress by regulating the expression of antioxidant enzymes, gamma-glutamylcysteine ligase (γGCL) and heme oxygenase-1 (HO-1). We investigated whether treadmill exercise protects dopaminergic neurons by regulating the Nrf2 antioxidant system in a 1-methyl-4-phenylpyridine (MPP(+))-induced parkinsonian rat model. We found that MPP(+) induced early decreases in total glutathione level and Nrf2/γGCLC (catalytic subunit of γGCL) expression, but late upregulation of HO-1 expression in association with loss of nigral dopaminergic neurons and downregulation of tyrosine hydroxylase and dopamine transporter expression in the striatum. Treadmill exercise for 4weeks induced upregulation of Nrf2 and γGCLC expression, and also prevented the MPP(+)-induced downregulation of Nrf2/γGCLC/glutathione, HO-1 upregulation, and nigrostriatal dopaminergic neurodegeneration. Moreover, the protective effect of exercise was blocked by the knockdown of Nrf2 using a lentivirus-carried shNrf2 delivery system. These results demonstrate an essential role of Nrf2 in the exercise-mediated protective effect that exercise enhances the nigrostriatal Nrf2 antioxidant defense capacity to protect dopaminergic neurons against the MPP(+)-induced toxicity.

Effects of synthetic colloids on oxidative stress and inflammatory response in hemorrhagic shock: comparison of hydroxyethyl starch 130/0.4, hydroxyethyl starch 200/0.5, and succinylated gelatin

INTRODUCTION

This study compared the effects of hydroxyethyl starch 130/0.4, hydroxyethyl starch 200/0.5, and succinylated gelatin on oxidative stress and the inflammatory response in a rodent hemorrhagic shock model.

METHODS

Sodium pentobarbital-anesthetized adult male Wistar rats (200 g to 220 g) were subjected to a severe volume-controlled hemorrhage using arterial blood withdrawal (30 mL/kg to 33 mL/kg) and resuscitated with a colloid solution at the same volume as blood withdrawal (hydroxyethyl starch 130/0.4, hydroxyethyl starch 200/0.5, or succinylated gelatin). Arterial blood gas parameters were monitored. Malondialdehyde (MDA) content and myeloperoxidase (MPO) activity in the liver, lungs, intestine, and brain were measured two hours after resuscitation. The levels of tumor necrosis factor-alpha (TNF-α) and interleukin-6 in the intestine were also measured.

RESULTS

Infusions of hydroxyethyl starch 130/0.4, but not hydroxyethyl starch 200/0.5 or succinylated gelatin, significantly reduced MDA levels and MPO activity in the liver, intestine, lungs and brain, and it also inhibited the production of TNF-α in the intestine two hours after resuscitation. However, no significant difference between hydroxyethyl starch 200/0.5 and succinylated gelatin was observed.

CONCLUSIONS

Hydroxyethyl starch 130/0.4, but not hydroxyethyl starch 200/0.5 or succinylated gelatin, treatment after hemorrhagic shock ameliorated oxidative stress and the inflammatory response in this rat model. No significant differences were observed after hydroxyethyl starch 200/0.5 or succinylated gelatin administration at doses of approximately 33 mL/kg.

Effects of different resuscitation fluids on pulmonary expression of aquaporin1 and aquaporin5 in a rat model of uncontrolled hemorrhagic shock and infection

BACKGROUND

To investigate the effects of fluids resuscitation on pulmonary expression of aquaporin1 and aquaporin5 in a rat model of uncontrolled hemorrhagic shock and infection.

METHODS

Sixty Sprague-Dawley rats were randomly assigned to five groups, sham operation group (Group C) and four treated groups: no fluid resuscitation group (Group NF), groups resuscitated with Lactated Ringer's (LR),7.5% NaCl (HTS) and Hydroxyl ethyl starch (HES) respectively. Three-phased uncontrolled hemorrhagic shock and infection model was used. Phase I: Massive hemorrhage with a mean arterial pressure of 35-40 mmHg for 60 min, and followed by infection of lipopolysaccharide. Then some animals were resuscitated with solutions mentioned above, until 90 min. Phase II: At hemorrhagic shock 90 minutes, phase II of 60 minutes began with hemostasis and returning of all the initial shed blood. Phase III: Observation phase for 3.5 hours. After phase III, arterial blood gas analysis and the survival rates of the rats were recorded, Wet-to-dry lung weight ratio, BALF protein, pulmonary permeability index, and expressions of aquaporin1 and aquaporin5 were tested.

RESULTS

The expressions of aquaporin1 and aquaporin5 were decreased in treatment groups comparing with sham operation group. Group HES and Group HTS decreased pulmonary vascular permeability and Wet-to-dry lung weight ratio, improved arterial blood gas analysis and survival rates, and attenuated the decreased pulmonary expression of aquaporin1 and aquaporin5 after the "two-hit", comparing with groups NF and LR,but these beneficial effects were blunted in group HTS.

CONCLUSION

The expression of aquaporin1 and aquaporin5 may play important roles in formation of pulmonary edema. Resuscitation with HTS and HES, especially HES can reduce lung injury after hemorrhagic shock, partly by up-regulating the expressions of aquaporin1 and aquaporin5.

Effects of Intravascular Volume Replacement on Lung and Kidney Function and Damage in Nonseptic Experimental Lung Injury

Background:

Intravascular volume replacement is often required in the presence of increased pulmonary capillary leakage, for example in patients with volutrauma with major hemorrhage. In the present study, the effects of Ringer’s acetate (RA), gelatin-polysuccinate (GEL), and a modern hydroxyethyl starch (HES, 6% 130/0.42) on lung and kidney function and damage were compared in a two-hit model of acute lung injury. The authors hypothesized that GEL and HES, compared to RA: (1) reduced lung histological damage, (2) impaired kidney morphology and function.

Methods:

Acute lung injury was induced in 30 anesthetized pigs by tidal volumes approximately 40 ml/kg, after saline lung lavage. Protective ventilation was initiated and approximately≈25% of estimated blood volume was drawn. Animals were randomly assigned to receive RA, GEL, or HES (n = 10/group) aimed at approximately 90% of intrathoracic blood volume before blood drainage.

Results:

Fluid volumes were higher with RA (2,250 ± 764 ml) than GEL (704 ± 159 ml) and HES (837 ± 82 ml) (P < 0.05). Compared to RA, HES reduced diffuse alveolar damage overall, and GEL in nondependent zones only. GEL and HES yielded lower wet-to-dry ratios compared to RA (6.5 ± 0.5 and 6.5 ± 0.6 vs. 7.9 ± 0.9, respectively, P < 0.05). HES and RA resulted in less kidney damage than GEL, but kidney function did not differ significantly among groups. Compared to GEL, HES yielded lower lung elastance (55 ± 12 vs. 45 ± 13 cm H2O/l, P < 0.05) and intra-abdominal pressure (15 ± 5 vs. 11 ± 4 cm 14;H2O, P < 0.05).

Conclusions:

In this model of acute lung injury, intravascular volume expansion after major hemorrhage with HES yielded less lung damage than RA and less kidney damage than GEL.

Resuscitation after hemorrhagic shock: the effect on the liver--a review of experimental data

The liver is currently considered to be one of the first organs to be subjected to the hypoxic insult inflicted by hemorrhagic shock. The oxidative injury caused by resuscitation also targets the liver and can lead to malfunction and the eventual failure of this organ. Each of the various fluids, vasoactive drugs, and pharmacologic substances used for resuscitation has its own distinct effect(s) on the liver, and the anesthetic agents used during surgical resuscitation also have an impact on hepatocytes. The aim of our study was to identify the specific effect of these substances on the liver. To this end, we conducted a literature search of MEDLINE for all types of articles published in English, with a focus on articles published in the last 12 years. Our search terms were "hemorrhagic shock," "liver," "resuscitation," "vasopressors," and "anesthesia." Experimental studies form the majority of articles found in bibliographic databases. The effect of a specific resuscitation agent on the liver is assessed mainly by measuring apoptotic pathway regulators and inflammation-induced indicators. Apart from a wide range of pharmacological substances, modifications of Ringer's Lactate, colloids, and pyruvate provide protection to the liver after hemorrhage and resuscitation. In this setting, it is of paramount importance that the treating physician recognize those agents that may attenuate liver injury and avoid using those which inflict additional damage.

Ringer's malate solution protects against the multiple organ injury and dysfunction caused by hemorrhagic shock in rats

Malic acid, in the form of its anion malate, is a key intermediate in the major biochemical energy-producing cycle known as the citric acid or Krebs cycle. In this study, the authors investigated the protective effect of a novel crystalloid solution of Ringer's malate following fluid resuscitation of hemorrhagic shock using a rat model. Under general anesthesia, Sprague-Dawley male rats were subjected to 60 min of hemorrhagic shock (40 mmHg for 60 min) followed by crystalloid resuscitation. Groups were as follows: (1) sham shock, (2) normal saline, (3) Ringer's lactate, and (4) Ringer's malate. The experiment was terminated at 4 h after resuscitation. Mean arterial blood pressure (MAP) and blood biophysical parameters were monitored during the experiment. The alanine aminotransferase, aspartate aminotransferase, urea, creatinine, superoxide dismutase, and malondialdehyde levels in plasma were detected. The intestine, liver, lung, and renal histopathology were measured. It was found that Ringer's malate could increase MAP immediately and maintain MAP for a long time. Ringer's malate could reduce the level of alanine aminotransferase, aspartate aminotransferase, urea, and creatinine. At the same time, the activity of superoxide dismutase was increased, and the level of malondialdehyde was decreased. Histopathology indicated that Ringer's malate can protect against the multiple organ injury caused by hemorrhagic shock in rats. Ringer's malate prevented circulatory failure and alleviated multiple organ dysfunction syndrome in animals with hemorrhagic shock. The study suggests that Ringer's malate solution could be a potential novel therapeutic agent for fluid resuscitation.

Protective effect of crocetin on hemorrhagic shock-induced acute renal failure in rats

Multiple organ failure is a common outcome of hemorrhagic shock followed by resuscitation, and the kidney is one of the prime target organs involved. The main objective of the study was to evaluate whether crocetin, a natural product from Gardenia jasminoides Ellis, has beneficial effects on renal dysfunction caused by hemorrhagic shock and resuscitation in rats. Anesthetized rats were bled to reduce mean arterial blood pressure to 35 (SD, 5) mmHg for 60 min and then were resuscitated with their withdrawn shed blood and normal saline. Crocetin was administered via the duodenum at a dose of 50 mg/kg 40 min after hemorrhage. The increase in creatinine and blood urea nitrogen was significantly reduced at 2 h after hemorrhage and resuscitation in crocetin-treated rats. The increases in renal nitric oxide, tumor necrosis factor α, and interleukin 6 were also attenuated by crocetin. Hemorrhagic shock resulted in a significant elevation in malondialdehyde production and was accompanied by a reduction in total superoxide dismutase activity, activation of nuclear factor κB, and overexpression of inducible nitric oxide synthase. These changes were significantly attenuated by crocetin at 2 h after resuscitation. These results suggested that crocetin blocks inflammatory cascades by inhibiting production of reactive oxygen species and restoring superoxide dismutase activity to ameliorate renal dysfunction caused by hemorrhage shock and resuscitation.

The role of toll-like receptor-4 in the development of multi-organ failure following traumatic haemorrhagic shock and resuscitation

Haemorrhagic shock and resuscitation (HS/R) following major trauma results in a global ischaemia and reperfusion injury that may lead to multiple organ dysfunction syndrome (MODS). Systemic activation of the immune system is fundamental to the development of MODS in this context, and shares many features in common with the systemic inflammatory response syndrome (SIRS) that complicates sepsis. An important advancement in the understanding of the innate response to infection involved the identification of mammalian toll-like receptors (TLRs) expressed on cells of the immune system. Ten TLR homologues have been identified in humans and toll-like receptor-4 (TLR4) has been studied most intensively. Initially found to recognise bacterial lipopolysaccharide (LPS), it has also recently been discovered that TLR4 is capable of activation by endogenous 'danger signal' molecules released following cellular injury; this has since implicated TLR4 in several non-infectious pathophysiologic processes, including HS/R. The exact events leading to multi-organ dysfunction following HS/R have not yet been clearly defined, although TLR4 is believed to play a central role as has been shown to be expressed at sites including the liver, lungs and myocardium following HS/R. Multi-organ dysfunction syndrome remains an important cause of morbidity and mortality in trauma patients, and current therapy is based on supportive care. Understanding the pathophysiology of HS/R will allow for the development of targeted therapeutic strategies aimed at minimising organ dysfunction and improving patient outcomes following traumatic haemorrhage. A review of the pathogenesis of haemorrhagic shock is presented, and the complex, yet critical role of TLR4 as both a key mediator and therapeutic target is discussed.

Melatonin attenuates brain contusion-induced oxidative insult, inactivation of signal transducers and activators of transcription 1, and upregulation of suppressor of cytokine signaling-3 in rats

The induction of oxidative stress and inflammation has been closely linked in traumatic brain injury (TBI). Transcriptional factors of signal transducers and activators of transcription (STAT) proteins are redox sensitive and participate in the regulation of cytokine signaling. Previous studies demonstrated that melatonin protects neurons through its antioxidative and anti-inflammatory effects in various neuropathological conditions. However, the effect of melatonin on STAT activity after TBI has not yet been explored. In this study, we used a controlled weight-drop TBI model and found that brain contusion induced oxidative stress (a decreased level of total glutathione and an increased ratio of oxidized glutathione to total glutathione), a reduction in STAT1 DNA-binding activity, and consequently neuronal loss in a contusion depth-dependent manner. A significant increased mRNA expression of suppressor of cytokine signaling (SOCS3), inducible nitric oxide synthetase (iNOS), and interleukine-6 (IL-6), but a decreased protein expression of protein inhibitor of activated STAT (PIAS1), was found 24 hr after brain contusion. SOCS3 and PIAS1 are endogenous negative regulators of STAT1. Moreover, the combination of intraperitoneal and local (presoaked in gelfoam and placed on the traumatic cortex) administration of melatonin had the most pronounced influence in inhibiting all effects except the PIAS1 downregulation induced by brain contusion. The results suggest that SOCS-3 upregulation and oxidative stress may contribute to the STAT1 inactivation after TBI. Melatonin protects neurons from TBI by reducing oxidative stress, STAT1 inactivation, and upregulation of SOCS-3 and pro-inflammatory cytokines.

Hydroxyethyl starch (130 kD) inhibits Toll-like receptor 4 signaling pathways in rat lungs challenged with lipopolysaccharide

BACKGROUND

A number of studies have shown that hydroxyethyl starch (HES) solutions are able to down-regulate the expression of inflammatory mediators and inhibit neutrophil-mediated tissue injuries when they are used in patients with sepsis or other diseases with severe inflammatory responses. However, our knowledge about the underlying mechanisms is limited. Toll-like receptor 4 (TLR4) signaling has a pivotal role in inflammatory processes. In this study, we examined the possible involvement of TLR4 signaling in the antiinflammatory effects of HES.

METHODS

Male Sprague-Dawley rats were exposed to lipopolysaccharide (LPS) (10 mg/kg, IV) and received IV saline (30 mL/kg) or HES 130/0.4 (15 or 30 mL/kg). Six hours after LPS challenge, rats were killed and their lungs harvested. Lung injury was examined by hematoxylin and eosin staining. TLR4 mRNA expression, p38 mitogen-activated protein kinase (MAPK) and extracellular signal-regulated kinases 1/2 MAPK activation, and activator protein 1 (AP-1) activity in the lungs were detected with quantitative polymerase chain reaction, Western blotting, and electrophoretic mobility shift assay, respectively.

RESULTS

Compared with saline, HES profoundly attenuated the histological changes induced by LPS in the lungs at both dose levels. Molecular analysis showed that both 15 and 30 mL/kg HES significantly decreased TLR4 mRNA levels and inhibited activation of p38 MAPK and AP-1 in rats challenged with LPS, whereas activation of extracellular signal-regulated kinases 1/2 MAPK was not affected by either dose of HES.

CONCLUSIONS

These findings indicate that the beneficial effects of HES 130/0.4 on inflammation are mediated at least in part by inhibiting the TLR4/p38 MAPK/AP-1 pathway in lungs from rats challenged with LPS.

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.

Fluid resuscitation: past, present, and the future

Hemorrhage remains a major cause of preventable death following both civilian and military trauma. The goals of resuscitation in the face of hemorrhagic shock are restoring end-organ perfusion and maintaining tissue oxygenation while attempting definitive control of bleeding. However, if not performed properly, resuscitation can actually exacerbate cellular injury caused by hemorrhagic shock, and the type of fluid used for resuscitation plays an important role in this injury pattern. This article reviews the historical development and scientific underpinnings of modern resuscitation techniques. We summarized data from a number of studies to illustrate the differential effects of commonly used resuscitation fluids, including isotonic crystalloids, natural and artificial colloids, hypertonic and hyperoncotic solutions, and artificial oxygen carriers, on cellular injury and how these relate to clinical practice. The data reveal that a uniformly safe, effective, and practical resuscitation fluid when blood products are unavailable and direct hemorrhage control is delayed has been elusive. Yet, it is logical to prevent this cellular injury through wiser resuscitation strategies than attempting immunomodulation after the damage has already occurred. Thus, we describe how some novel resuscitation strategies aimed at preventing or ameliorating cellular injury may become clinically available in the future.

Optimal fluid resuscitation: timing and composition of intravenous fluids

BACKGROUND

Recent data suggest that the timing of fluid resuscitation and the type of fluid used to treat hemorrhagic shock contribute to the inflammatory response as well as cell death.

METHODS

Rats were bled of 40% of their total blood volume and then resuscitated in either early or delayed fashion. Treatment was assigned randomly and consisted of lactated Ringer's solution, normal saline, bicarbonate Ringer's solution, hypertonic saline, or no resuscitation. The first four groups were subdivided into early and late resuscitation. After a 5-h observation period, lung and liver samples were evaluated for apoptosis, and blood was collected for measurements of the cytokines interleukin (IL)-6, IL-10, and IL-1beta.

RESULTS

The rats that were not resuscitated had significantly more apoptosis in liver tissue. In the lung, bicarbonate Ringer's solution, when given early, was associated with significantly less apoptosis. Non-resuscitated rats had significantly higher IL-6 concentrations than all other groups. Animals receiving hypertonic saline early had significantly higher IL-6 concentrations than those given any other fluid. The concentration of IL-1beta was significantly higher in the non-resuscitated rats than in those receiving bicarbonate Ringer's, lactated Ringer's, or normal saline for early resuscitation. Interleukin-10 was elevated significantly in non-resuscitated rats.

CONCLUSIONS

Cellular destruction and a pro-inflammatory response follow hemorrhagic shock. Early resuscitation with isotonic crystalloid fluids decreases these responses.

Effects of different resuscitation fluids on acute lung injury in a rat model of uncontrolled hemorrhagic shock and infection

BACKGROUND

To investigate the effects of different resuscitation fluids on acute lung injury in a rat model of uncontrolled hemorrhagic shock (HS) followed by mimicked infection.

METHODS

Sixty Sprague-Dawley rats were randomly assigned to one of the five groups (n = 12 per group) to receive the following treatments: (1) control group (group C), surgery, no hemorrhage, and no resuscitation; (2) no fluid resuscitation group; (3) lactated Ringer's solution group; (4) 7.5% hypertonic saline (HTS) group; and (5) hydroxyethyl starch group (group HES). All experimental groups were subjected to three phases: phase I entailed massive hemorrhage with a mean arterial pressure of 35 mm Hg to 40 mm Hg for 60 minutes by tail amputation and followed by mimicked infection by intratracheal administration of lipopolysaccharide 2 mg/kg. The animals in each group were then partially resuscitated with the fluid assigned to the group. Phase II of 60 minutes commenced at tail ligation, involved hemostasis, and return of all the blood initially shed. Phase III was an observation phase with no any further treatment and lasted for 3.5 hours. The survival rate at the end of the phase III was recorded. After phase III, arterial blood gases were recorded. The wet to dry lung weight ratio, pulmonary microvascular permeability, the expression of transforming growth factor (TGF)-beta1, and Smad2 were determined. The lung histology was also assessed.

RESULTS

HES and HTS solutions were more effective than no fluid resuscitation and lactated Ringer's solution in reducing the detrimental effects of HS and infection on the lungs, as seen by the significantly lower pulmonary microvascular permeability and wet to dry lung weight ratio, the improved arterial blood gases and lower levels of TGF-beta1and Smad2 expression in lung tissues. These beneficial effects were most pronounced in the group HES.

CONCLUSIONS

This study demonstrated that resuscitation with HTS and especially with HES could reduce lung tissue damage and pulmonary edema after severe uncontrolled HS. The TGF-beta1/Smad2 signaling pathway might play a key role in regulation of pulmonary permeability and formation of pulmonary edema in a rat model of uncontrolled HS and infection.

Influence of hydroxyethyl starch on healing of colonic anastomosis in a rat model of peritonitis

BACKGROUND

This study was designed to evaluate the role of different intravascular volume replacement regimens of HES 130/0.4 on wound healing process in left colonic anastomoses in the presence of intra-abdominal sepsis induced by murine model of cecal ligation and puncture (CLP).

METHODS

The left colonic anastomosis was performed in 40 rats that were divided into five groups (n = 8/group): saline controls (30 ml/kg); CLP plus saline (30 ml/kg); CLP plus HES (7.5, 15, or 30 ml/kg, respectively). Saline or HES was treated before the construction of left colonic anastomosis and on a regular daily basis. Anastomotic bursting pressures were measured in vivo on day 5. Tissue samples were obtained for analyses of hydroxyproline (HP) contents, myeloperoxidase (MPO) activity, malondialdehyde (MDA), reduced glutathione (GSH) levels, and nuclear factor-kappa B (NF-kappa B) activation. The plasma levels of tumor necrosis factor (TNF)-alpha and interleukin (IL)-6 were also measured.

RESULTS

Intra-abdominal sepsis led to significant decreases in colonic anastomotic bursting pressures, and perianastomotic tissue HP contents and GSH levels, along with increases in perianastomotic tissue MPO activity, MDA levels and NF-kappa B activation and plasma levels of TNF-alpha and IL-6. After treated with HES, these provoked perianastomotic tissue MPO activity, MDA levels, NF-kappa B activation, and plasma levels of TNF-alpha and IL-6 were suppressed and GSH levels were restored, especially in 15 ml/kg HES group. Without obvious influence on systemic nutritional condition, HES 15 ml/kg but not HES 7.5 ml/kg significantly increased anastomotic bursting pressures, and perianastomotic tissue HP contents. However, HES 30 ml/kg even led to adverse effects on anastomotic bursting pressures.

CONCLUSIONS

This study showed that moderate doses (15 ml/kg) of HES 130/0.4 administration significantly prevented this intraperitoneal sepsis-induced impaired anastomotic healing of the left colon. It also suggested the possibility of poorer anastomotic healing receiving HES at higher doses (30 ml/kg). Clearly, HES 130/0.4 now should not be recommended to use at a high doses postoperatively in sepsis.

Hydroxyethyl starch 130/0.4 augments healing of colonic anastomosis in a rat model of peritonitis

BACKGROUND

This study was designed to investigate the role of hydroxyethyl starch (HES) 130/0.4 on the wound healing process in left colonic anastomoses in the presence of intra-abdominal sepsis.

METHODS

The left colonic anastomosis was performed in 40 rats that were divided into 4 groups: (1) group SHAM, laparatomy plus cecal mobilization (n = 10); (2) group SHAM + HES, HES130/.4-treated controls (n = 10); and (3) group CLP, cecal ligation and puncture (n = 10); (4) group CLP + HES, CLP plus HES130/.4 (n = 10). HES130/.4 was administrated before the construction of colonic anastomosis, 15 mL/kg/24 hours and daily for 4 postoperative days. Anastomotic bursting pressures (ABPs) were measured in vivo on day 5. Tissue samples were obtained for analyses of hydroxyproline (HP) contents, myeloperoxidase (MPO) activity, malondialdehyde (MDA), reduced glutathione (GSH) levels, and nuclear factor-kappaB (NF-kappaB) activation. The plasma levels of tumor necrosis factor (TNF)-alpha, interleukin (IL)-6, d-dimer, and protein C (PC) were also measured. Anastomotic granulation tissues were fixed for transmission electron microscopic (TEM) analyses.

RESULTS

Intra-abdominal sepsis led to significant decreases in colonic anastomotic bursting pressures, perianastomotic tissue HP contents, GSH levels, and plasma levels of PC, along with increases in perianastomotic tissue MPO activity, MDA levels, NF-kappaB activation, and plasma levels of TNF-alpha, IL-6, and d-dimer. However, HES130/.4 treatment significantly inhibited all these responses. TEM analyses revealed that there was a trend toward a higher density of fibroblast distribution and a higher rate of fibroblast activation in the SHAM- and HES 130/0.4-treated animals, compared with the CLP group.

CONCLUSIONS

This study showed that moderate doses (15 mL/kg) of HES 130/0.4 administration significantly prevented this intraperitoneal sepsis-induced impaired anastomotic healing of the left colon. This beneficial effect of HES 130/0.4 can be mainly attributed to its anti-inflammatory and antioxidant properties and beneficial effects of modulating endothelial-associated coagulopathy.

Hydroxyethyl starch 130/0.4 inhibits production of plasma proinflammatory cytokines and attenuates nuclear factor-kappaB activation and Toll-like receptors expression in monocytes during sepsis

BACKGROUND

Hydroxyethyl starch (HES) is one of the most frequently used plasma substitutes, and could modulate inflammatory response in sepsis. Our aim of this study was to investigate the mechanism of the effect of HES 130/0.4 by studying plasma levels of inflammatory cytokines, nuclear factor-kappaB (NF-kappaB) activation, and Toll-like receptors (TLRs) expression in peripheral monocytes during polymicrobial sepsis.

MATERIALS AND METHODS

Rats with sepsis induced by cecal ligation and puncture (CLP) were treated with HES130/0.4 (7.5, 15, or 30 mL/kg, intravenously); then, rat plasma and monocytes were isolated from blood 5 h later. The plasma level of cytokines (tumor necrosis factor [TNF]-alpha and interleukin [IL]-6), NF-kappaB activity, and mRNA and protein levels of TLRs (TLR2 and TLR4) in peripheral blood monocytes were determined by enzyme-linked immunosorbent assay, electrophoretic mobility shift assay, reverse transcription-polymerase chain reaction, and Western blotting, respectively.

RESULTS

HES130/0.4 dose-dependently reduced the plasma level of TNF-alpha and IL-6 in rats with sepsis. HES130/0.4 also significantly inhibited NF-kappaB activation, and TLRs mRNA and protein levels in peripheral monocytes.

CONCLUSION

During sepsis, HES130/0.4 can down-regulate the inflammatory response, possibly through inhibition of the TLRs/NF-kappaB signaling pathway, and could be one more appropriate plasma substitute in sepsis.

Resuscitation with hydroxyethyl starch solution prevents CD4+ T-lymphocyte apoptosis and modulates the balance of T helper type 1 and T helper type 2 responses in the rat with traumatic virgule/shill hemorrhagic shock

Trauma/hemorrhagic shock (TH/S) has been associated with inflammation and immunodisorders, leading to immunosuppression, multiorgan dysfunction, and death. However, little is known about the effect of resuscitation with different solutions on the immunological function. To address this issue, groups of male Sprague-Dawley rats were induced with TH/S by fracture in the left femur and continual bleeding to keep the MAP of 30 +/- 5 mmHg for 30 min, followed by resuscitation with 6% hydroxyethyl starch solution (HES), Ringer's lactate solution (RS), or 5% albumin (ALB), and the impact of resuscitation on the activation, differentiation, and survival of CD4 T cells was longitudinally examined after TH/S and resuscitation. After resuscitation, the MAP, as expected, gradually increased regardless of the type of fluids transfused. The percentage of CD4+ T cells decreased to 20% to 25%, and the ratio of T helper type 1 (TH1)/TH2 responses was significantly reduced in all TH/S rats, however, resuscitation with HES alone reversed the trends (49.4% +/- 9.7% vs. 55.2% +/- 2.6% in sham for CD4 T cells; 0.64 +/- 0.23 vs. 0.71 +/- 0.16 in sham for the ratio of TH1/TH2, P > 0.05 for both). Treatment with HES or ALB, but not RS, prevented CD4 T-cell apoptosis (sham, 7.23% +/- 3.4%; HES, 10.2% +/- 4.1%; RS, 15.2% +/- 5.4%; ALB, 10.6% +/- 4.3%; 48 h) and nuclear factor-kappaB p65 activation (sham, 0.17 +/- 0.04; HES, 0.34 +/- 0.05; RS, 0.41 +/- 0.09; ALB, 0.25 +/- 0.09; 48 h) induced by TH/S early after resuscitation. These data demonstrated that HES resuscitation modulated the balance of TH1 and TH2 responses and inhibited TH/S-related nuclear factor-kappaB activation and CD4 T-cell apoptosis in TH/S rats. Our findings provide new insights into understanding the TH/S-related immunodisorders and may aid in the design of new therapy for intervention of TH/S.

Prevention of hemorrhagic shock-induced intestinal tissue injury by glutamine via heme oxygenase-1 induction

Hemorrhagic shock (HS) is an oxidative stress that causes intestinal tissue injury. Heme oxygenase 1 (HO-1) is induced by oxidative stress and is thought to play an important role in the protection of tissues from oxidative injury. We previously reported the ileum to be the most susceptible to HS-induced tissue injury site in the intestine because HO-1 induction is the lowest at this site. We also previously demonstrated that glutamine (GLN) significantly induced HO-1 in the lower intestinal tract. In the present study, we investigated whether GLN pretreatment improves HS-induced intestinal tissue injury in the ileum by HO-1 induction. Treatment of rats with GLN (0.75 g/kg, i.v.) markedly induced functional HO-1 protein in mucosal epithelial cells in the ileum. Glutamine treatment before HS (MAP of 30 mmHg for 60 min) significantly ameliorated HS-induced mucosal inflammation and apoptotic cell death in the ileum, as judged by significant decreases in gene expression of TNF-alpha, iNOS, intercellular adhesion molecule 1, and vascular cell adhesion molecule 1, myeloperoxidase activity, the number of infiltrated neutrophils, DNA fragmentation by in situ oligo ligation assay, and activated caspase-3 expression, and by increases in gene expression of IL-10 and Bcl-2. In contrast, treatment with tin mesoporphyrin, a specific inhibitor of HO activity, abolished the beneficial effect of GLN pretreatment. These findings indicate that GLN pretreatment significantly ameliorated tissue injury in the ileum after HS by inducing HO-1. Glutamine treatment may thus protect mucosal cells from HS-induced oxidative damage via the anti-inflammatory and antiapoptotic properties of HO-1.