A Novel Cross-Linked Hemoglobin-Based Oxygen Carrier, YQ23, Extended the Golden Hour for Uncontrolled Hemorrhagic Shock in Rats and Miniature Pigs.

Background: Hypotensive resuscitation is widely applied for trauma and war injury to reduce bleeding during damage-control resuscitation, but the treatment time window is limited in order to avoid hypoxia-associated organ injury. Whether a novel hemoglobin-based oxygen carrier (HBOC), YQ23 in this study, could protect organ function, and extend the Golden Hour for treatment is unclear. Method: Uncontrolled hemorrhagic shock rats and miniature pigs were infused with 0.5, 2, and 5% YQ23 before bleeding was controlled, while Lactate Ringer's solution (LR) and fresh whole blood plus LR (WB + LR) were set as controls. During hypotensive resuscitation the mean blood pressure was maintained at 50-60 mmHg for 60 min. Hemodynamics, oxygen delivery and utilization, blood loss, fluid demand, organ function, animal survival as well as side effects were observed. Besides, in order to observe whether YQ23 could extend the Golden Hour, the hypotensive resuscitation duration was extended to 180 min and animal survival was observed. Results: Compared with LR, infusion of YQ23 in the 60 min pre-hospital hypotensive resuscitation significantly reduced blood loss and the fluid demand in both rats and pigs. Besides, YQ23 could effectively stabilize hemodynamics, and increase tissue oxygen consumption, increase the cardiac output, reduce liver and kidney injury, which helped to reduce the early death and improve animal survival. In addition, the hypotensive resuscitation duration could be extended to 180 min using YQ23. Side effects such as vasoconstriction and renal injury were not observed. The beneficial effects of 5% YQ23 are equivalent to similar volume of WB + LR. Conclusion: HBOC, such as YQ23, played vital roles in damage-control resuscitation for emergency care and benefited the uncontrolled hemorrhagic shock in the pre-hospital treatment by increasing oxygen delivery, reducing organ injury. Besides, HBOC could benefit the injured and trauma patients by extending the Golden Hour.

Role of AQP3 in the Vascular Leakage of Sepsis and the Protective Effect of Ss-31.

ABSTRACT: Aquaporins (AQPs) are a group of membrane proteins related to water permeability. Studies have shown that AQPs play a vital role in various diseases. Whether AQPs participate in regulating vascular permeability after sepsis and whether the subtype of AQPs is related are unknown. Ss-31, as a new antioxidant, had protective effects on a variety of diseases. However, whether Ss-31 has a protective effect on pulmonary vascular permeability in sepsis and whether its effect is related to AQPs are unclear. Using the cecum ligation perforation-induced septic rat and LPS-treated pulmonary vein endothelial cells, the role of AQPs in the regulation of the permeability of pulmonary vascular and its relationship to Ss-31 were studied. The results showed that the pulmonary vascular permeability significantly increased after sepsis, meanwhile the expressions of AQP3, 4, and 12 increased. Among those, the AQP3 was closely correlated with pulmonary vascular permeability. The inhibition of AQP3 antagonized the increase of the permeability of monolayer pulmonary vein endothelial cells. Further study showed that the expression of caveolin-1 (Cav-1) increased and occludin decreased after sepsis. The inhibition of AQP3 antagonized the decrease of Cav-1 and the increase of occludin in sepsis. Antioxidant Ss-31 decreased the expression of AQP3 and ROS levels. At the same time, Ss-31 improved pulmonary vascular permeability and prolonged survival of sepsis rats. In conclusion, AQP3 participates in the regulation of pulmonary vascular permeability after sepsis, and the antioxidant Ss-31 has a protective effect on pulmonary vascular permeability by downregulating the expression of AQP3 and inhibiting ROS production.

The Calcilytic Drug Calhex-231 Ameliorates Vascular Hyporesponsiveness in Traumatic Hemorrhagic Shock by Inhibiting Oxidative Stress and miR-208a-Mediated Mitochondrial Fission.

BACKGROUND: The calcium-sensing receptor (CaSR) plays a fundamental role in extracellular calcium homeostasis in humans. Surprisingly, CaSR is also expressed in nonhomeostatic tissues and is involved in regulating diverse cellular functions. The objective of this study was to determine if Calhex-231 (Cal), a negative modulator of CaSR, may be beneficial in the treatment of traumatic hemorrhagic shock (THS) by improving cardiovascular function and investigated the mechanisms. METHODS: Rats that had been subjected to THS and hypoxia-treated vascular smooth muscle cells (VSMCs) were used in this study. The effects of Cal on cardiovascular function, animal survival, hemodynamics, and vital organ function in THS rats and the relationship to oxidative stress, mitochondrial fusion-fission, and microRNA (miR-208a) were investigated. RESULTS: Cal significantly improved hemodynamics, elevated blood pressure, increased vital organ blood perfusion and local oxygen supply, and markedly improved the survival outcomes of THS rats. Furthermore, Cal significantly improved vascular reactivity after THS in vivo and in vitro. Cal also restored the THS-induced decrease in myosin light chain (MLC) phosphorylation (the key element for VSMC contraction). Inhibition of MLC phosphorylation antagonized the Cal-induced restoration of vascular reactivity following THS. Cal suppressed oxidative stress in THS rats and hypoxic-VSMCs. Meanwhile, THS induced expression of mitochondrial fission proteins Drp1 and Fis1 and decreased expression of mitochondrial fusion protein Mfn1 in vascular tissues. Cal reduced expression of Drp1 and Fis1. In hypoxic-VSMCs, Cal inhibited mitochondrial fragmentation and preserved mitochondrial morphology. In addition, miR-208a mimic decreased Fis1 expression, and miR-208a inhibitor prevented Cal-induced Fis1 downregulation in hypoxic-VSMCs. CONCLUSION: Calhex-231 exhibits outstanding potential for effective therapy of traumatic hemorrhagic shock, and the beneficial effects result from its protection of vascular function via inhibition of oxidative stress and miR-208a-mediated mitochondrial fission.

Synergistic effects of EMPs and PMPs on pulmonary vascular leakage and lung injury after ischemia/reperfusion.

BACKGROUND: Vascular leakage is an important pathophysiological process of critical conditions such as shock and ischemia-reperfusion (I/R)-induced lung injury. Microparticles (MPs), including endothelial cell-derived microparticles (EMPs), platelet-derived microparticles (PMPs) and leukocyte-derived microparticles (LMPs), have been shown to participate in many diseases. Whether and which of these MPs take part in pulmonary vascular leakage and lung injury after I/R and whether these MPs have synergistic effect and the underlying mechanism are not known. METHODS: Using hemorrhage/transfusion (Hemo/Trans) and aorta abdominalis occlusion-induced I/R rat models, the role of EMPs, PMPs and LMPs and the mechanisms in pulmonary vascular leakage and lung injury were observed. RESULTS: The concentrations of EMPs, PMPs and LMPs were significantly increased after I/R. Intravenous administration of EMPs and PMPs but not LMPs induced pulmonary vascular leakage and lung injury. Furthermore, EMPs induced pulmonary sequestration of platelets and promoted more PMPs production, and played a synergistic effect on pulmonary vascular leakage. MiR-1, miR-155 and miR-542 in EMPs, and miR-126 and miR-29 in PMPs, were significantly increased after hypoxia/reoxygenation (H/R). Of which, inhibition of miR-155 in EMPs and miR-126 in PMPs alleviated the detrimental effects of EMPs and PMPs on vascular barrier function and lung injury. Overexpression of miR-155 in EMPs down-regulated the expression of tight junction related proteins such as ZO-1 and claudin-5, while overexpression of miR-126 up-regulated the expression of caveolin-1 (Cav-1), the trans-cellular transportation related protein such as caveolin-1 (Cav-1). Inhibiting EMPs and PMPs production with blebbistatin (BLE) and amitriptyline (AMI) alleviated I/R induced pulmonary vascular leakage and lung injury. CONCLUSIONS: EMPs and PMPs contribute to the pulmonary vascular leakage and lung injury after I/R. EMPs mediate pulmonary sequestration of platelets, producing more PMPs to play synergistic effect. Mechanically, EMPs carrying miR-155 that down-regulates ZO-1 and claudin-5 and PMPs carrying miR-126 that up-regulates Cav-1, synergistically mediate pulmonary vascular leakage and lung injury after I/R. Video Abstract.

Mdivi-1 attenuates oxidative stress and exerts vascular protection in ischemic/hypoxic injury by a mechanism independent of Drp1 GTPase activity.

Vascular dysfunctions such as vascular hyporeactivity following ischemic/hypoxic injury are a major cause of death in injured patients. In this study, we showed that treatment with mitochondrial division inhibitor 1 (Mdivi-1), a selective inhibitor of dynamin-related protein 1 (Drp1), significantly improved vascular reactivity in ischemic rats by attenuating oxidative stress. The antioxidative effects of Mdivi-1 were relatively Drp1-independent, and possibly due to an increase in the levels of the antioxidant enzymes, SOD1 and catalase, as well as to enhanced Nrf2 expression. In addition, we found that while Mdivi-1 had little effect on Drp1 GTPase activity in vascular smooth muscle cells, it inhibited hypoxia-induced Drp1 phosphorylation at Ser-616, reducing excessive mitochondrial fission and slightly enhancing mitochondrial fusion. These effects possibly contributed to vascular protection at an early stage of ischemic/hypoxic injury. Finally, Mdivi-1 stabilized hemodynamics, increased vital organ perfusion, and improved rat survival after ischemic/hypoxic injury, proving a promising therapeutic agent for ischemic/hypoxic injury.

Endothelial Microvesicles Induce Pulmonary Vascular Leakage and Lung Injury During Sepsis.

Sepsis is a prevalent severe syndrome in clinic. Vascular leakage and lung injury are important pathophysiological processes during sepsis, but the mechanism remains obscure. Microvesicles (MVs) play an essential role in many diseases, while whether MVs participate in vascular leakage and lung injury during sepsis is unknown. Using cecal ligation and puncture induced sepsis rats and lipopolysaccharide stimulated vascular endothelial cells (VECs), the role and the underlying mechanism of endothelial microvesicles (EMVs) in pulmonary vascular leakage and lung injury were observed. The role of MVs from sepsis patients was verified. The results showed that the concentration of MVs in blood was significantly increased after sepsis. MVs from sepsis rats and patients induced apparent pulmonary vascular leakage and lung injury, among which EMVs played the dominant role, in which miR-23b was the key inducing factor in vascular leakage. Furthermore, downregulation and upregulation of miR-23b in EMVs showed that miR-23b mainly targeted on ZO-1 to induce vascular leakage. MVs from sepsis patients induced pulmonary vascular leakage and lung injury in normal rats. Application of classic antidepressants amitriptyline reduced the secretion of EMVs, and alleviated vascular leakage and lung injury. The study suggests that EMVs play an important role in pulmonary vascular leakage and lung injury during sepsis by transferring functional miR-23b. Antagonizing the secretion of EMVs and the miR-23b might be a potential target for the treatment of severe sepsis.

Research advances in pericyte function and their roles in diseases.

Pericyte, a kind of pluripotent cell, may regulate the irrigation flow and permeability of microcirculation. Pericytes are similar to the smooth muscle cells, which express several kinds of contractile proteins and have contractility. The dysfunction of pericytes is related to many microvascular diseases, including hypoxia, hypertension, diabetic retinopathy, fibrosis, inflammation, Alzheimer's disease, multiple sclerosis, and tumor formation. For a long time, their existence and function have been neglected. The distribution, structure, biomarker, related signaling pathways as well as the roles of pericytes on vascular diseases will be introduced in this review.

A novel cross-linked haemoglobin-based oxygen carrier is beneficial to sepsis in rats.

Pathological hypoxia-induced organ dysfunction contributes to the high mortality of sepsis. Because of the microcirculation dysfunction following severe sepsis, it is difficult for erythrocytes to transport oxygen to hypoxic tissues. Haemoglobin-based oxygen carriers (HBOCs) are capable of delivering oxygen to hypoxic tissues. The aim of this study is to observe the potential benefits of a novel bovine-derived, non-polymerized, cell-free HBOC solution, YQ23, on sepsis in rats. Cecum ligation and puncture was performed to induce sepsis in Sprague-Dawley rats. Effects of Lactate Ringer's solution (LR), YQ23, and whole blood on oxygen delivery and consumption, mitochondrial function, organ protection and animal survival were observed. LR failed to restore oxygen delivery and the therapeutic effects were limited, whereas low dosage of YQ23 and whole blood significantly increased the tissue oxygen delivery and consumption, improved the mitochondrial function of heart, liver, kidney and intestine, prevented the vital organs injuries and improved the animal survival. The effects of 0.15 g·kg-1 YQ23 resembled that of the whole blood. In addition, YQ23 did not induce renal toxicity, severe oxidative effect and acute vasoconstriction. Thus, YQ23 is a safe and effective resuscitation fluid for sepsis.

Identification of ideal resuscitation pressure with concurrent traumatic brain injury in a rat model of hemorrhagic shock.

BACKGROUND: Traumatic brain injury (TBI) is often associated with uncontrolled hemorrhagic shock (UHS), which contributes significantly to the mortality of severe trauma. Studies have demonstrated that permissive hypotension resuscitation improves the survival for uncontrolled hemorrhage. What the ideal target mean arterial pressure (MAP) is for TBI with UHS remains unclear. METHODS: With the rat model of TBI in combination with UHS, we investigated the effects of a series of target resuscitation pressures (MAP from 50-90 mm Hg) on animal survival, brain perfusion, and organ function before hemorrhage controlled. RESULTS: Rats in 50-, 60-, and 70-mm Hg target MAP groups had less blood loss and less fluid requirement, a better vital organ including mitochondrial function and better cerebral blood flow, and animal survival (8, 6, and 7 of 10, respectively) than 80- and 90-mm Hg groups. The 70-mm Hg group had a better cerebral blood flow and cerebral mitochondrial function than in 50- and 60-mm Hg groups. In contrast, 80- and 90-mm Hg groups resulted in an excessive hemodilution, a decreased blood flow, an increased brain water content, and more severe cerebral edema. CONCLUSIONS: A 50-mm Hg target MAP is not suitable for the resuscitation of TBI combined with UHS. A 70 mm Hg of MAP is the ideal target resuscitation pressure for this trauma, which can keep sufficient perfusion to the brain and keep good organ function including cerebral mitochondrial function.

Small doses of arginine vasopressin in combination with norepinephrine "buy" time for definitive treatment for uncontrolled hemorrhagic shock in rats.

Implementation of fluid resuscitation and blood transfusion are greatly limited in prehospital or evacuation settings after severe trauma or war wounds. With uncontrolled hemorrhagic shock rats, we investigated if arginine vasopressin (AVP) in combination with norepinephrine (NE) is independent (or slightly dependent) of fluid resuscitation and can "buy" time for the subsequently definitive treatment of traumatic hemorrhagic shock in the present study. The results showed that AVP (0.4 U/kg) alone or with NE (3 µg/kg) with one-eighth and one-fourth volumes of total blood volume of lactated Ringer's infusion significantly increased and maintained the mean arterial pressure. Among all groups, 0.4 U/kg of AVP + NE (3 µg/kg) with one-eighth volume of lactated Ringer's infusion had the best effect: it significantly increased and maintained hemodynamics and prolonged the survival time. This early treatment strategy significantly improved the effects of subsequently definitive treatments (after bleeding controlled): it increased the subsequent survival, improved the hemodynamic parameters, improved the cardiac function, and increased the tissue blood flow and oxygen delivery. These results suggested that early application of small doses of AVP (0.4 U/kg) + NE before bleeding control can "buy" time for the definitive treatment of uncontrolled hemorrhagic shock, which may be an effective measure for the early treatment of traumatic hemorrhagic shock.

Ideal resuscitation pressure for uncontrolled hemorrhagic shock in different ages and sexes of rats.

INTRODUCTION: Our previous studies demonstrated that 50-60 mmHg mean arterial blood pressure was the ideal target hypotension for uncontrolled hemorrhagic shock during the active hemorrhage in sexually mature rats. The ideal target resuscitation pressure for immature and older rats has not been determined. METHODS: To elucidate this issue, using uncontrolled hemorrhagic-shock rats of different ages and sexes (6 weeks, 14 weeks and 1.5 years representing pre-adult, adult and older rats, respectively), the resuscitation effects of different target pressures (40, 50, 60, 70 and 80 mmHg) on uncontrolled hemorrhagic shock during active hemorrhage and the age and sex differences were observed. RESULTS: Different target resuscitation pressures had different resuscitation outcomes for the same age and sex of rats. The optimal target resuscitation pressures for 6-week-old, 14-week-old and 1.5-year-old rats were 40 to 50 mmHg, 50 to 60 mmHg and 70 mmHg respectively. Ideal target resuscitation pressures were significantly superior to other resuscitation pressures in improving the hemodynamics, blood perfusion, organ function and animal survival of uncontrolled hemorrhagic-shock rats (P < 0.01). For same target resuscitation pressures, the beneficial effect on hemorrhagic shock had a significant age difference (P < 0.01) but no sex difference (P > 0.05). Different resuscitation pressures had no effect on coagulation function. CONCLUSION: Hemorrhagic-shock rats at different ages have different target resuscitation pressures during active hemorrhage. The ideal target resuscitation hypotension for 6-week-old, 14-week-old and 1.5-year-old rats was 40 to 50 mmHg, 50 to 60 mmHg and 70 mmHg, respectively. Their resuscitation effects have significant age difference but had no sex difference.

Quasiclassical dynamics simulation of the collision-induced dissociation of Cr(CO)6 + with Xe.

Quasiclassical trajectory calculations are employed to investigate the dynamics of collision-induced dissociation (CID) of Cr(CO)6 + with Xe atoms at collision energies ranging from 1.3 to 5.0 eV. The trajectory simulations show that direct elimination of CO ligands, during the collision, becomes increasingly important as the collision energy increases. In a significant number of cases, this shattering mechanism is accompanied with a concomitant formation of a transient Xe-Cr(CO)x +(x<6) complex. The calculated results are in very good agreement with the experimental results presented previously [F. Muntean and P. B. Armentrout, J. Chem. Phys. 115, 1213 (2001)]. In particular, the computed cross sections and scattering maps for the product ions Cr(CO)x +(x=3-5) compare very favorably with the reported experimental data. However, in contrast with the conclusions of the previous study, the present calculations suggest that CID dynamics for this system exhibits a significant impulsive character rather than proceeding via a complex surviving more than a rotational period.