The role of intrinsic apoptotic signaling in hemorrhagic shock-induced microvascular endothelial cell barrier dysfunction

Shenfu injection alleviate gut ischemia/reperfusion injury after severe hemorrhagic shock through improving intestinal microcirculation in rats

Background

Shenfu (SF) injection, a traditional Chinese medication, would improve microcirculation in cardiogenic shock and infectious shock. This study was aimed to explore the therapeutic potential of the SF injection in gut ischemia-reperfusion (I/R) injury after severe hemorrhagic shock (SHS) and resuscitation. Furthermore, we also investigated the optimal adm？ inistration timing.

Methods

Twenty-four male SD rats were randomly divided into four groups: Sham group (sham, n = 6), Control group (n = 6), SF injection group (SF, n = 6), and Delayed Shenfu injection administration group (SF-delay, n = 6). In SHS and resuscitation model, rats were induced by blood draw to a mean arterial pressure (MAP) of 40 ± 5 mmHg within 1 h and then maintained for 40 min; HR, MAP 'were recorded, microcirculation index [De Backer score, perfused small vessel density (PSVD), total vessel density (TVD), microcirculation flow index score (MFI), flow heterogeneity index (HI)] were analyzed. The blood gas index was detected, interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), diamine oxidase (DAO), malondialdehyde (MDA) were measured by ELISA; ZO-1, and claudin-1 were measured by Western blotting. In addition, hematoxylin-eosin (HE) and periodic acid schiff (PAS) staining pathological sections of the intestinal mucosal tissues were also performed.

Results

SF injection increased the MAP, relieved the metabolic acidosis degree associated with the hypoperfusion, and improved the intestinal microcirculatory density and perfusion quality after I/R injury. The expression of DAO, MDA in intestinal tissue, and plasma IL-6, TNF-α significantly decreased in the SF injection group compared to the control group. The concentration of ZO-1 and claudin-1 is also higher in the SF injection group. In addition, the HE and PAS staining results also showed that SF injection could decrease mucosal damage and maintain the structure. In the SF-delay group, the degree of intestinal tissue damage was intermediate between that of the control group and SF injection group.

Conclusions

SF injection protect the intestine from I/R injury induced by SHS and resuscitation, the mechanism of which might be through improving intestinal microcirculation, reducing the excessive release of inflammatory factors and increasing intestinal mucosal permeability. Furthermore, the protection effect is more pronounced if administration during the initial resuscitation phase.

Evaluation of Glycolysis and Mitochondrial Function in Endothelial Cells Using the Seahorse Analyzer

Endothelial bioenergetics have emerged as a key regulator of endothelial barrier function. Glycolytic parameters have been linked to barrier enhancement, and interruption with mitochondrial complexes was shown to disrupt endothelial barrier. Therefore, a new technology that has been introduced to assess bioenergetics and metabolism has also made it possible to determine roles of specific energy production pathways in endothelial health. The Seahorse extracellular flux analysis by Agilent technologies is a state of the art tool that has been more frequently used to evaluate bioenergetics of endothelial cells. This chapter includes details about different assays that can be used to study endothelial cells using the Seahorse analyzer and how interpretation of the results can provide novel insight about endothelial metabolism.

Effects of Propofol Combined with Sufentanil Target-Controlled Intravenous Anesthesia on Expression of Bax, Bcl-2, and Caspase-3 Genes in Spontaneous Hypertensive Rats with Cerebral Hemorrhage: a Prospective Case-Controlled Study

It is a well-known fact that general anesthesia leads to cerebral hemorrhage in patients with spontaneous hypertension apart of the fact that the hypertension is under control. The literature is already flooded with this debate, and still, there appears a lag regarding the effects of high blood pressure on pathological changes in the brain after cerebral hemorrhage. They are still not well recognized. Furthermore, it is the stage of anesthesia resuscitation which is known to have adverse effects on the body during cerebral hemorrhage. Owing to the lag of knowledge in the above said facts, the objectives of this study were to evaluate the effects of propofol combined with sufentanil on the expression of Bax, BCL-2, and caspase-3 genes in spontaneously hypertensive rats suffering with cerebral hemorrhage. The initial sample consisted of 54 male Wrister rats. All were of the age of 7 to 8 months with a weight of 500 ± 100 gm. All the rats were evaluated by the investigators before enrolment. A total of 0.5 mg/kg ketamine followed by a 10 mg/kg intravenous injection of propofol was introduced to each included rat. It was followed by a total of 1 μG/kg/h of sufentanil which was administered to rats who had cerebral hemorrhage (n = 27). The rest 27 normal rats were not administered with sufentanil. Hemodynamic parameters, biochemistry, western blot assay, and immunohistochemical staining were performed. The results were statistically analyzed. Heart rate (p < 0.0001) was higher for rats who had a cerebral hemorrhage. The cytokine levels of rats who had cerebral hemorrhage were higher than those of normal rats (p < 0.01 for all). Bacl-2 (p < 0.01), bax (p < 0.01), and caspase-3 (p < 0.01) expressions were reported to be disturbed in rats who had cerebral hemorrhage. Urine volume was reduced in rats who had cerebral hemorrhage (p < 0.01). It was concluded that in spontaneously hypertensive rats with cerebral hemorrhage, propofol combined with sufentanil target-controlled intravenous anesthesia increased hemodynamic parameters and cytokine levels. Furthermore, cerebral hemorrhage disturbs the expression of bacl-2, Bax, and caspase-3 expressions.

Edema and lymphatic clearance: molecular mechanisms and ongoing challenges

Resolution of edema remains a significant clinical challenge. Conditions such as traumatic shock, sepsis, or diabetes often involve microvascular hyperpermeability, which leads to tissue and organ dysfunction. Lymphatic insufficiency due to genetic causes, surgical removal of lymph nodes, or infections, leads to varying degrees of tissue swelling that impair mobility and immune defenses. Treatment options are limited to management of edema as there are no specific therapeutics that have demonstrated significant success for ameliorating microvascular leakage or impaired lymphatic function. This review examines current knowledge about the physiological, cellular, and molecular mechanisms that control microvascular permeability and lymphatic clearance, the respective processes for interstitial fluid formation and removal. Clinical conditions featuring edema, along with potential future directions are discussed.

Ferulic acid protects renal tubular epithelial cells against anoxia/reoxygenation injury mediated by AMPKα1

Anoxia/reoxygenation (A/R) injury causes dysfunction of rat renal tubular epithelial cells (NRK-52E), which is associated with excess reactive oxygen species (ROS) generation and eventually leads to apoptosis. Ferulic acid (FA), a phenolic acid, which is abundant in fruits and vegetables. FA possesses the properties of scavenging free radicals and cytoprotection against oxygen stress. In the study, the protective effects of FA against NRK-52E cells damage induced by A/R were explored and confirmed the role of AMP-activated protein kinaseα1 (AMPKα1). We found that after NRK-52E cells suffered A/R damage, FA pretreatment increased the cell viability and decreased LDH activity in culture medium in a concentration-dependent manner, the activities of endogenous antioxidant enzymes such as glutathione peroxidase, superoxide dismutase and catalase improved, intracellular ROS generation and malondialdehyde contents mitigated. In addition, pretreatment of 75 μM FA ameliorated mitochondrial dysfunction by A/R-injury and ultimately decreased apoptosis (25.3 ± 0.61 vs 12.1 ± 0.60), which was evidenced by preventing the release of cytochrome c from mitochondria to the cytoplasm. 75 μM FA pretreatment also significantly upregulated AMPKα1 expression (3.16 ± 0.18 folds) and phosphorylation (2.56 ± 0.13 folds). However, compound C, a specific AMPK inhibitor, significantly attenuated FA pretreatment's effects, as mentionedabove. These results firstly clarified that FA pretreatment attenuated NRK-52E cell damage induced by A/R via upregulating AMPKα1 expression and phosphorylation.

ETS-Related Gene Activation Preserves Adherens Junctions and Permeability in Microvascular Endothelial Cells

ABSTRACT

ERG (ETS-related gene) is a member of the ETS (Erythroblast-transformation specific) family of transcription factors abundantly present in vascular endothelial cells. Recent studies demonstrate that ERG has important roles in blood vessel stability and angiogenesis. However, it is unclear how ERG is potentially involved in microvascular barrier functions and permeability. A wide variety of diseases and clinical conditions including trauma-hemorrhagic shock and burn injury are associated with microvascular dysfunctions, which causes excessive microvascular permeability, tissue edema and eventually, multiple organ dysfunction and death. The main purpose of this study was to determine the specific role of ERG in regulating microvascular permeability in human lung microvascular endothelial cells (HLMEC) and to evaluate if exogenous ERG will protect the barrier. The HLMECs were grown on Transwell inserts as monolayers and were transfected with ERG CRISPR/cas9 knockdown plasmid, ERG CRISPR activation plasmid, recombinant ERG protein or their respective controls. Recombinant vascular endothelial growth factor (VEGF) was used as an inducer of permeability for evaluating the effect of ERG activation on permeability. Changes in barrier integrity and permeability were studied using monolayer permeability assay and immunofluorescence of adherens junction proteins (VE-cadherin and β-catenin) respectively. CRISPR/cas9-based ERG knockdown as well as VEGF treatment induced monolayer hyperpermeability, VE-cadherin, and β-catenin junctional relocation and cytoskeletal F-actin stress fiber formation. CRISPR based ERG activation and recombinant ERG transfection attenuated VEGF-induced monolayer hyperpermeability. ERG activation preserved the adherens junctions and cytoskeleton. These results demonstrate that ERG is a potent regulator of barrier integrity and permeability in human lung microvascular endothelial cells and endogenously or exogenously enhancing ERG provides protection against barrier dysfunction and hyperpermeability.

Endothelial cell-derived SSAO can increase MLC20 phosphorylation in VSMCs

Vascular hyporesponsiveness in the shock decompensation period is an important factor leading to death. Myosin light chain 20 (MLC₂₀) is the main effector protein that regulates vascular reactivity. However, whether the change in semicarbazide-sensitive amine oxidase (SSAO) expression during hypoxia can change the MLC₂₀ phosphorylation level, and its underlying mechanism were not clear. The amine oxidase copper containing 3 (AOC3) overexpressing adenovirus vector was constructed and transfected into rat intestinal microvascular endothelial cells (RIMECs) to overexpress SSAO, and the RIMECs were co-cultured with rat intestinal microvascular smooth muscle cells (RIMSCs). The changes in SSAO/inducible nitric oxide synthase (iNOS)/Rho associate coiled-coil containing protein kinase 1 (ROCK1) expression levels and MLC₂₀ phosphorylation level were detected. Here we found that the increased SSAO by AOC3 overexpression can decrease the iNOS expression level and its activity after hypoxia. In addition, RIMSCs co-cultured with RIMECs overexpressed with AOC3 gene had significantly higher ROCK1 protein level and MLC₂₀ phosphorylation level than RIMSCs co-cultured with normal RIMECs. Our study demonstrated that SSAO overexpression can significantly inhibit iNOS activity, promote RhoA/ROCK pathway activation, and increase the phosphorylation level of MLC₂₀, which might be the potential mechanism in relieving the vascular hyporesponsiveness during shock decompensation.

CD226 deficiency promotes glutaminolysis and alleviates mitochondria damage in vascular endothelial cells under hemorrhagic shock

Hemorrhagic shock (HS) is common in clinical emergencies, leading to millions of deaths each year globally. CD226 is a costimulatory adhesion molecule expressed on both immune cells and endothelial cells (ECs) to regulate their metabolic activity and function. As endothelial dysfunction occurs after HS, the roles CD226 plays in vascular EC metabolism were investigated. CD226^fl/fl Tek^cre mice were adopted to achieve vascular EC-specific knockout of CD226, and subjected to HS modelling. Serum levels of crucial intermediate metabolites were evaluated through liquid chromatography-mass spectrometry analysis. Human umbilical vein ECs (HUVECs) were used to study the effects of CD226 under hypoxia in vitro. Seahorse analysis evaluated the cellular glycolysis and mitochondria bioenergetics. Results showed that CD226 deficiency in vascular ECs alleviated HS-induced intestinal damage and inflammatory response in mice. Animal studies indicated an improved energy metabolism when CD226 was knocked out in ECs after HS, as evidenced by enhanced glutamine-glutamate metabolism and decreased lactic acid levels. Glut-1 was upregulated in mouse vascular ECs after HS and HUVECs under hypoxia, combined with decreased CD226. Moreover, HUVECs with CD226 knockdown exhibited relieved mitochondrial damage and early apoptosis under hypoxia, whereas CD226 overexpression showed opposite effects. Seahorse analysis showed that downregulated CD226 significantly increased mitochondrial ATP production and glucose uptake in HUVECs under hypoxia. Additionally, Erk/PHD2 signaling-mediated HIF-1α/Glut-1 and HIF-2α/ASCT2 pathways were involved in CD226 regulation on HUVEC glutaminolysis after hypoxia. Hence, CD226 deficiency promotes bypass energy supply to vascular ECs under ischemic or hypoxic stress, to ameliorate the stress-mediated metabolic disturbance.

Protective effects of FK 506 against haemorrhagic shock-induced microvascular hyperpermeability

Microvascular hyperpermeability, the excessive leakage of fluid and proteins from the intravascular space to the interstitium, is a devastating clinical concern in haemorrhagic shock (HS), sepsis, burn and so forth. Previous studies have shown that HS-induced microvascular hyperpermeability is associated with activation of the mitochondria-mediated 'intrinsic' apoptotic signalling cascade and caspase-3 mediated disruption of the endothelial cell barrier. In this study, our objective was to test if FK506, an immunomodulator that is also known to protect mitochondria, would protect barrier functions and decrease vascular hyperpermeability following HS by acting on this pathway. FK506 (25 µM) was given 10 minutes before the shock period in a rat model of HS. The HS model was a non-traumatic/fixed pressure model of hypovolemic shock developed by withdrawing blood to reduce the mean arterial pressure to 40 mm Hg for 60 minutes. The mesenteric post-capillary venules were monitored for changes in permeability using intravital microscopic imaging. The changes in mitochondrial transmembrane potential (MTP) were determined using the cationic dye 5,5',6,6' tetrachoro-1,1',3,3' tetraethyl benzimidazolyl carbocyanine iodide (JC-1), that was superfused on the mesenteric vasculature followed by intravital imaging. The mesenteric caspase-3 activity was measured fluorometrically. Haemorrhagic shock induced a significant increase in hyperpermeability compared to the sham-control group and FK506 treatment decreased HS-induced hyperpermeability significantly (P < .05). FK506 dampened HS-induced loss of MTP and elevation of caspase-3 activity significantly (P < .05). FK506 has protective effects against HS-induced microvascular hyperpermeability. The maintenance of the MTP and protection against caspase-3 mediated endothelial cell barrier disruption are possible mechanisms by which FK506 attenuates HS-induced hyperpermeability. FK506, currently used in clinical settings as an immunomodulator, needs to be explored further for its therapeutic usefulness against HS-induced vascular hyperpermeability and associated complications.

Role of albumin on endothelial basement membrane and hemostasis in a rat model of hemorrhagic shock

BACKGROUND

We sought to determine the extent of loss of endothelial basement membrane (BM), leukocyte recruitment, and changes in coagulation after hemorrhagic shock, followed by limited-volume resuscitation (LVR) with 5% albumin (ALB).

METHODS

Anesthetized rats were bled 40% of blood volume and assigned to treatment groups: untreated (n = 6), LVR with normal saline (NS; n = 8), or LVR with ALB (n = 8). Sham rats (n = 6) underwent all procedures except hemorrhage or resuscitation. Blood samples were assayed for active proteases, such as metalloproteinase 9 (MMP-9) and a disintegrin and metalloproteinase 10 (ADAM-10), BM-type heparan sulfate proteoglycan (perlecan), cell count, and coagulation function. Leukocyte transmigration was used to estimate the net efficiency of leukocyte recruitment in cremaster venules.

RESULTS

Hemorrhage significantly lowered red cell count, but white cell and platelet counts did not change (vs. sham). Ionized calcium in plasma was significantly reduced in untreated and remained so after NS. In contrast, ionized calcium was normalized after ALB. Plasma expansion after NS and ALB further reduced leukocyte and platelet counts. Metalloproteinase 9, ADAM-10, and perlecan were significantly higher in untreated rats (vs. sham). Albumin normalized MMP-9, ADAM-10, and perlecan levels, while NS further increased MMP-9, ADAM-10, and perlecan (vs. sham). Transmigrated leukocytes doubled in the untreated group and remained elevated after NS (vs. sham) but normalized after ALB. Albumin reduced every stage of the leukocyte recruitment process to sham levels.

CONCLUSION

Despite similar plasma expansion, NS weakened platelet function contrary to ALB. Plasma expansion with ALB resulted in restoration of BM integrity and attenuation of leukocyte recruitment to tissues, in contrast to NS. Albumin plays a critical role in restoring BM integrity, attenuating leukocyte recruitment to tissues, and optimizing hemostasis by increasing ionized calcium in plasma.

Shenfu injection improves cerebral microcirculation and reduces brain injury in a porcine model of hemorrhagic shock

BACKGROUND

Shenfu injection (SFI) is a traditional Chinese herbal medicine which has been clinically used for treatment of septic shock and cardiac shock. The aim of this study was to clarify effects of SFI on cerebral microcirculation and brain injury after hemorrhagic shock (HS).

METHODS

Twenty-one domestic male Beijing Landrace pigs were randomly divided into three groups: SFI group (SFI, n = 8), saline group (SA, n = 8) or sham operation group (SO, n = 5). In the SFI group, animals were induced to HS by rapid bleeding to a mean arterial pressure of 40 mmHg within 10 minutes and maintained at 40±3 mmHg for 60 minutes. Volume resuscitation (shed blood and crystalloid) and SFI were given after 1 hour of HS. In the SA group, animals received the same dose of saline instead of SFI. In the SO group, the same surgical procedure was performed but without inducing HS and volume resuscitation. The cerebral microvascular flow index (MFI), nitric oxide synthase (NOS) expression, aquaporin-4 expression, interleukin-6, tumor necrosis factor-α (TNF-α) and ultrastructural of microvascular endothelia were measured.

RESULTS

Compared with the SA group, SFI significantly improved cerebral MFI after HS. SFI up regulated cerebral endothelial NOS expression, but down regulated interleukin-6, TNF-α, inducible NOS and aquaporin-4 expression compared with the SA group. The cerebral microvascular endothelial injury and interstitial edema in the SFI group were lighter than those in the SA group.

CONCLUSIONS

Combined application of SFI with volume resuscitation after HS can improve cerebral microcirculation and reduce brain injury.

Identification of Fibrinogen as a Key Anti-Apoptotic Factor in Human Fresh Frozen Plasma for Protecting Endothelial Cells In Vitro

Resuscitation with human fresh frozen plasma (FFP) in hemorrhagic shock (HS) patients is associated with improved clinical outcomes. Our group has demonstrated that the beneficial effect of FFP is due to its blockade on endothelial hyperpermeability, thereby improving vascular barrier function. The current study aimed to investigate HS-induced endothelial cell apoptosis, a potential major contributor to the endothelial hyperpermeability, and to determine the effect and the key components/factors of FFP on protecting endothelial cells from apoptosis. We first measured and demonstrated an increase in apoptotic endothelial microparticles (CD146AnnexinV) in patients in shock compared to normal subjects, indicating the induction of endothelial cell activation and apoptosis in shock patients. We then transfused HS rats with FFP and showed that FFP blocked HS-induced endothelial cell apoptosis in gut tissue. To identify the anti-apoptotic factors in FFP, we utilized high-performance liquid chromatography, fractionated FFP, and screened the fractions in vitro for the anti-apoptotic effects. We selected the most effective fractions, performed mass spectrometry, and identified fibrinogen as a potent anti-apoptotic factor. Taken together, our findings suggest that HS-induced endothelial apoptosis may constitute a major mechanism underlying the vascular hyperpermeability. Furthermore, the identified anti-apoptotic factor fibrinogen may contribute to the beneficial effects of FFP resuscitation, and therefore, may have therapeutic potential for HS.

Shen-fu injection alleviates acute renal injury by reducing cytokine levels and modulating apoptosis in a porcine hemorrhagic shock model

PURPOSE

Shen-fu injection (SFI) was used to intervene in the resuscitation of porcine hemorrhagic shock (HS) model to study its protective effects on acute kidney injury.

METHODS

After 60 min of HS, 28 animals were randomly assigned into four groups. The groups were as follows: hemorrhagic shock group (HS); HS resuscitation with shed-blood group (HSR); HS resuscitation with shed-blood and SFI (1 mL·kg-1) group (HSR-SFI); and the sham operation group (Sham). The bloods were analyzed for serum creatinine (sCr), cystatin C (CysC) and neutrophil gelatinase-associated lipocalin (NGAL). BAX, Bcl-2, and caspase-3 protein expressions by Western blot analysis and immunohistochemical staining. The renal tissues were removed and pathologic changes were observed.

RESULTS

Mean aortic pressure (MAP) in HSR-SFI groups were higher than that in HSR groups after shock. At the 6th hour after shock, the urine volume per hour in the HSR-SFI groups was more than that in the HSR groups. The sCr, NGAL, CysC and cytokine levels of HSR-SFI groups were lower. The Bcl-2 expression was increased in the HSR-SFI groups. The BAX and caspase-3 expressions were reduced. The histopathologic score in the HSR-SFI was lower.

CONCLUSIONS

SFI may reduce the risk of acute kidney injury (AKI) following hemorrhagic shock by attenuating systemic inflammatory responses, and regulating the expression of apoptosis-related proteins.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Swine hemorrhagic shock model and pathophysiological changes in a desert dry-heat environment

BACKGROUND

This study aimed to establish a traumatic hemorrhagic shock (THS) model in swine and examine pathophysiological characteristics in a dry-heat environment.

METHODS

Forty domestic Landrace piglets were randomly assigned to four study groups: normal temperature non-shock (NS), normal temperature THS (NTHS), desert dry-heat non-shock (DS), and desert dry-hot THS (DTHS) groups. The groups were exposed to either normal temperature (25°C) or dry heat (40.5°C) for 3 h. To induce THS, anesthetized piglets in the NTHS and DTHS groups were subjected to liver trauma and hypovolemic shock until death, and piglets in the NS and DS groups were euthanized at 11 h and 4 h, respectively. Body temperature, blood gas, cytokine production, and organ function were assessed before and after environmental exposure at 0 h and at every 30 min after shock to death. Hemodynamics was measured post exposure and post-shock at 0 h and at every 30 min after shock to death.

RESULTS

Survival, body temperature, oxygen delivery, oxygen consumption, and cardiac output were significantly different for traumatic hemorrhagic shock in the dry-heat groups compared to those in the normal temperature groups. Lactic acid and IL-6 had a marked increase at 0.5 h, followed by a progressive and rapid increase in the DTHS group.

CONCLUSIONS

Our findings suggest that the combined action of a dry-heat environment and THS leads to higher oxygen metabolism, poorer hemodynamic stability, and earlier and more severe inflammatory response with higher mortality.

Reperfusion using lactate Ringer's mixture partially eliminates IGF II receptor involved cardiac damage caused by hemorrhagic shock in diabetic rats

Diabetes is a metabolic disorder that damages many organs. We investigated the effects of reperfusion using lactate Ringer's solution (LR) in a diabetic animal model. Eight-week-old rats were divided into groups: control, hemorrhagic shock induced (HS), diabetes mellitus (DM), DM plus HS (DM + HS) and DM rats that received LR after HS (DM + HS + LR). HS was induced by withdrawing blood from the femoral artery and arterial pressure was maintained at 40 mm Hg for 1 h. Animals were perfused with either withdrawn blood or LR. Rats were sacrificed and hearts were collected from all groups. Histopathological studies were performed using left ventricles and western blotting analysis was performed using protein extracted from the left ventricle. Using the TUNEL assay, we found more apoptotic cells in the DM + HS group compared to the control group, whereas in animals resuscitated with LR, the number of apoptotic cells was reduced. Western blotting showed a significant reduction in apoptotic markers, cyt c, cas 9 and cas 3, and increased survival markers, pPI3K and pAKT, in the DM + HS + LR group. Reperfusion with LR may have therapeutic effects on trauma induced HS by blocking the IGF II R facilitated apoptosis pathway in diabetic rats.

Endothelial Protrusions in Junctional Integrity and Barrier Function

Endothelial cells of the microcirculation form a semi-permeable diffusion barrier between the blood and tissues. This permeability of the endothelium, particularly in the capillaries and postcapillary venules, is a normal physiological function needed for blood-tissue exchange in the microcirculation. During inflammation, microvascular permeability increases dramatically and can lead to tissue edema, which in turn can lead to dysfunction of tissues and organs. The molecular mechanisms that control the barrier function of endothelial cells have been under investigation for several decades and remain an important topic due to the potential for discovery of novel therapeutic strategies to reduce edema. This review highlights current knowledge of the cellular and molecular mechanisms that lead to endothelial hyperpermeability during inflammatory conditions associated with injury and disease. This includes a discussion of recent findings demonstrating temporal protrusions by endothelial cells that may contribute to intercellular junction integrity between endothelial cells and affect the diffusion distance for solutes via the paracellular pathway.

Hemorrhagic Shock and the Microvasculature

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

[Pathophysiology of hemorragic shock]

This review addresses the pathophysiology of hemorrhagic shock, a condition produced by rapid and significant loss of intravascular volume, which may lead to hemodynamic instability, decreases in oxygen delivery, decreased tissue perfusion, cellular hypoxia, organ damage, and death. The initial neuroendocrine response is mainly a sympathetic activation. Haemorrhagic shock is associated altered microcirculatory permeability and visceral injury. It is also responsible for a complex inflammatory response associated with hemostasis alteration.

Resveratrol Improves Survival and Prolongs Life Following Hemorrhagic Shock

Resveratrol has been shown to potentiate mitochondrial function and extend longevity; however, there is no evidence to support whether resveratrol can improve survival or prolong life following hemorrhagic shock. We sought to determine whether (a) resveratrol can improve survival following hemorrhage and resuscitation and (b) prolong life in the absence of resuscitation. Using a hemorrhagic injury (HI) model in the rat, we describe for the first time that the naturally occurring small molecule, resveratrol, may be an effective adjunct to resuscitation fluid. In a series of three sets of experiments we show that resveratrol administration during resuscitation improves survival following HI (p < 0.05), resveratrol and its synthetic mimic SRT1720 can significantly prolong life in the absence of resuscitation fluid (<30 min versus up to 4 h; p < 0.05), and resveratrol as well as SRT1720 restores left ventricular function following HI. We also found significant changes in the expression level of mitochondria-related transcription factors Ppar-α and Tfam, as well as Pgc-1α in the left ventricular tissues of rats subjected to HI and treated with resveratrol. The results indicate that resveratrol is a strong candidate adjunct to resuscitation following severe hemorrhage.