bims-heshmo 2021-08-08 papers

bims-heshmo

Biomed News

on Trauma hemorrhagic shock — molecular basis

Issue of 2021‒08‒08
sixteen papers selected by
Andreia Luís
Ludwig Boltzmann Institute

The impact of prehospital tranexamic acid on mortality and transfusion requirements: match-pair analysis from the nationwide German TraumaRegister DGU®.
Poloxamer 188 Attenuates Ischemia-Reperfusion-Induced Lung Injury by Maintaining Cell Membrane Integrity and Inhibiting Multiple Signaling Pathways.
IL-1β primed mesenchymal stromal cells moderate hemorrhagic shock-induced organ injuries.
A retrospective analysis of calcium levels in pediatric trauma patients.
Inhibition of Cardiac RIP3 Mitigates Early Reperfusion Injury and Calcium-Induced Mitochondrial Swelling without Altering Necroptotic Signalling.
Flow-dependent regulation of endothelial Tie2 by GATA3 in vivo.
Monocyte Dysfunction Detected by the Designed Ankyrin Repeat Protein F7 Predicts Mortality in Patients Receiving Veno-Arterial Extracorporeal Membrane Oxygenation.
Tracking oxidation-induced alterations in fibrin clot formation by NMR-based methods.
Pharmacological activation of SIRT1 by metformin prevented trauma-induced heterotopic ossification through inhibiting macrophage mediated inflammation.
The Endothelial Glycocalyx as a Double-Edged Sword in Microvascular Homeostasis and Pathogenesis.
Transcriptomic Hallmarks of Ischemia-Reperfusion Injury.
The Potential Role of Extracorporeal Cytokine Removal in Hemodynamic Stabilization in Hyperinflammatory Shock.
Inflammatory Mechanisms Contributing to Endothelial Dysfunction.
Emerging Approaches to Understanding Microvascular Endothelial Heterogeneity: A Roadmap for Developing Anti-Inflammatory Therapeutics.
Myostatin Deficiency Protects C2C12 Cells from Oxidative Stress by Inhibiting Intrinsic Activation of Apoptosis.
Regional thermal hyperemia in the human leg: Evidence of the importance of thermosensitive mechanisms in the control of the peripheral circulation.

Crit Care. 2021 Aug 04. 25(1): 277

The impact of prehospital tranexamic acid on mortality and transfusion requirements: match-pair analysis from the nationwide German TraumaRegister DGU®.

Sebastian Imach, Arasch Wafaisade, Rolf Lefering, Andreas Böhmer, Mark Schieren, Victor Suárez, Matthias Fröhlich, .

  BACKGROUND: Outcome data about the use of tranexamic acid (TXA) in civilian patients in mature trauma systems are scarce. The aim of this study was to determine how severely injured patients are affected by the widespread prehospital use of TXA in Germany.METHODS: The international TraumaRegister DGU® was retrospectively analyzed for severely injured patients with risk of bleeding (2015 until 2019) treated with at least one dose of TXA in the prehospital phase (TXA group). These were matched with patients who had not received prehospital TXA (control group), applying propensity score-based matching. Adult patients (≥ 16) admitted to a trauma center in Germany with an Injury Severity Score (ISS) ≥ 9 points were included.
RESULTS: The matching yielded two comparable cohorts (n = 2275 in each group), and the mean ISS was 32.4 ± 14.7 in TXA group vs. 32.0 ± 14.5 in control group (p = 0.378). Around a third in both groups received one dose of TXA after hospital admission. TXA patients were significantly more transfused (p = 0.022), but needed significantly less packed red blood cells (p ≤ 0.001) and fresh frozen plasma (p = 0.023), when transfused. Massive transfusion rate was significantly lower in the TXA group (5.5% versus 7.2%, p = 0.015). Mortality was similar except for early mortality after 6 h (p = 0.004) and 12 h (p = 0.045). Among non-survivors hemorrhage as leading cause of death was less in the TXA group (3.0% vs. 4.3%, p = 0.021). Thromboembolic events were not significantly different between both groups (TXA 6.1%, control 4.9%, p = 0.080).
CONCLUSION: This is the largest civilian study in which the effect of prehospital TXA use in a mature trauma system has been examined. TXA use in severely injured patients was associated with a significantly lower risk of massive transfusion and lower mortality in the early in-hospital treatment period. Due to repetitive administration, a dose-dependent effect of TXA must be discussed.

Keywords:  Bleeding; Coagulopathy; Hemostatic disorders; Mass transfusion; TXA; Tranexamic acid; Trauma; Trauma care

DOI:  https://doi.org/10.1186/s13054-021-03701-7
Front Pharmacol. 2021 ;12 650573

Poloxamer 188 Attenuates Ischemia-Reperfusion-Induced Lung Injury by Maintaining Cell Membrane Integrity and Inhibiting Multiple Signaling Pathways.

Shih-En Tang, Wen-I Liao, Hsin-Ping Pao, Chin-Wang Hsu, Shu-Yu Wu, Kun-Lun Huang, Shi-Jye Chu.

  Background: Poloxamer 188 (P188) possesses anti-inflammatory properties and can help to maintain plasma membrane function. P188 has been reported to exert beneficial effects in the treatment of various disorders. However, the effects of P188 in ischemia/reperfusion (IR)-induced acute lung injury have not been examined. Methods: We investigated the ability of P188 to attenuate IR-induced acute lung injury in rats and hypoxia/reoxygenation (HR) injury in murine epithelial cells. Isolated perfused rat lungs were exposed to 40 min ischemia followed by 60 min reperfusion to induce IR injury. Results: IR led to lung edema, increased pulmonary arterial pressure, promoted lung tissue inflammation and oxidative stress, and upregulated the levels of TNF-α, IL-6 and CINC-1, and increased Lactic dehydrogenase (LDH) activity in bronchoalveolar lavage fluid. IR also downregulated the levels of inhibitor of κB (IκB-α), upregulated nuclear factor (NF)-κB (NF-κB), and promoted apoptosis in lung tissues. P188 significantly suppressed all these effects. In vitro, P188 also exerted a similar effect in murine lung epithelial cells exposed to HR. Furthermore, P188 reduced the number of propidium iodide-positive cells, maintained cell membrane integrity, and enhanced cell membrane repair following HR. Conclusion: We conclude that P188 protects against lung IR injury by suppressing multiple signaling pathways and maintaining cell membrane integrity.

Keywords:  acute lung injury; hypoxia/reoxygenation; ischemia-reperfusion; membrane integrity; poloxamer 188

DOI:  https://doi.org/10.3389/fphar.2021.650573
Stem Cell Res Ther. 2021 Aug 05. 12(1): 438

IL-1β primed mesenchymal stromal cells moderate hemorrhagic shock-induced organ injuries.

Clotilde Aussel, Nathalie Baudry, Marion Grosbot, Cécile Caron, Eric Vicaut, Sébastien Banzet, Juliette Peltzer.

  BACKGROUND: Organ damages following hemorrhagic shock (HS) have been partly attributed to an immunological dysfunction. The current challenge in the management of HS patients is to prevent organ injury-induced morbidity and mortality which currently has not etiological treatment available. Mesenchymal stromal cells (MSC) are used in clinical cell therapy for immunomodulation and tissue repair. In vitro priming is often used to improve the immunomodulation efficiency of MSC before administration.OBJECTIVE: Assess the effect of naive MSC (MSCn) or interleukin (IL)-1β primed (MSCp) treatment in a context of HS-induced organ injury.
METHODS: Rats underwent fixed pressure HS and were treated with allogenic MSCn or MSCp. Liver and kidney injuries were evaluated 6h later by histological and biochemical analysis. Whole blood was collected to measure leukocytes phenotypes. Then, in vitro characterization of MSCn or MSCp was carried out.
RESULTS: Plasma creatinine, blood urea nitrogen, and cystatin C were decrease by MSCp infusion as well as kidney injury molecule (KIM)-1 on histological kidney sections. Transaminases, GGT, and liver histology were normalized by MSCp. Systemic cytokines (IL-1α, IL-6, and IL-10) as well as CD80, 86, and PD-1/PDL-1 axis were decreased by MSCp on monocytes and granulocytes. In vitro, MSCp showed higher level of secreted immunomodulatory molecules than MSCn.
CONCLUSION: An early administration of MSCp moderates HS-induced kidney and liver injury. IL-1β priming improves MSC efficiency by promoting their immunomodulatory activity. These data provide proof of concept that MSCp could be a therapeutic tool to prevent the appearance of organs injury following HS.

Keywords:  Hemorrhagic shock; IL-1β; Immunomodulation; Mesenchymal stromal cells; Multiple organ dysfunction syndrome; Priming

DOI:  https://doi.org/10.1186/s13287-021-02505-4
Int J Burns Trauma. 2021 ;11(3): 267-274

A retrospective analysis of calcium levels in pediatric trauma patients.

Brian G Cornelius, Daniel Clark, Ben Williams, Anna Rogers, Andreea Popa, Phillip Kilgore, Urska Cvek, Marjan Trutschl, Kevin Boykin, Angela Cornelius.

Traumatic injury is a major cause of morbidity and mortality in pediatric patients. Hemorrhage is a known but treatable component of these outcomes. Evidence exists that major trauma patients are at high risk for hypocalcemia but the rate of pediatric occurrence is not documented. The purpose of this study was to determine the incidence of hypocalcemia in pediatric trauma patients, as well as to investigate any correlation between hypocalcemia and the need for transfusion and operative intervention. After IRB approval a retrospective analysis was conducted of all pediatric trauma patients seen in our Adult Level One, Pediatric Level Two trauma center. Significance testing for mortality was performed using Pearson's χ2 test. For the remaining numeric variables, association was determined one-way analysis of variance (when comparing all classes) or Welch's two-sample t-test (when comparing subsets based on calcium or mortality). In any event, significance was determined using α=0.05. A total of 2,928 patients were identified, 1623 were excluded, primarily due to incomplete data. Patients were predominantly male following blunt trauma. Initial calcium levels were 8.73 mg/dL, 95% CI [4-10.9] and 8.97 mg/dL, 95% CI [6.42-13.1] when correcting for albumin levels. Acute declines were noted when comparing initial and corrected serum calcium levels in patients requiring transfusion (7.99 mg/dL and 8.72 mg/dL) and operative intervention (8.54 mg/dL and 8.91 mg/dL). 456 (34.9%) patients required operative intervention, 138 (10.6%) required transfusion and 29 (2.2%) required massive transfusion. Patients in our cohort arrived with calcium values on the low end of normal, with a trend towards hypocalcemia if operative intervention or blood transfusion was required. This has been previously associated with increased mortality. Patients requiring operative intervention and transfusion are at increased risk for hypocalcemia and recognition of this potential is key for improved outcomes.

Keywords: Hypocalcemia; pediatric; transfusion; trauma
Int J Mol Sci. 2021 Jul 26. pii: 7983. [Epub ahead of print]22(15):

Inhibition of Cardiac RIP3 Mitigates Early Reperfusion Injury and Calcium-Induced Mitochondrial Swelling without Altering Necroptotic Signalling.

Csaba Horvath, Megan Young, Izabela Jarabicova, Lucia Kindernay, Kristina Ferenczyova, Tanya Ravingerova, Martin Lewis, M Saadeh Suleiman, Adriana Adameova.

  Receptor-interacting protein kinase 3 (RIP3) is a convergence point of multiple signalling pathways, including necroptosis, inflammation and oxidative stress; however, it is completely unknown whether it underlies acute myocardial ischemia/reperfusion (I/R) injury. Langendorff-perfused rat hearts subjected to 30 min ischemia followed by 10 min reperfusion exhibited compromised cardiac function which was not abrogated by pharmacological intervention of RIP3 inhibition. An immunoblotting analysis revealed that the detrimental effects of I/R were unlikely mediated by necroptotic cell death, since neither the canonical RIP3-MLKL pathway (mixed lineage kinase-like pseudokinase) nor the proposed non-canonical molecular axes involving CaMKIIδ-mPTP (calcium/calmodulin-dependent protein kinase IIδ-mitochondrial permeability transition pore), PGAM5-Drp1 (phosphoglycerate mutase 5-dynamin-related protein 1) and JNK-BNIP3 (c-Jun N-terminal kinase-BCL2-interacting protein 3) were activated. Similarly, we found no evidence of the involvement of NLRP3 inflammasome signalling (NOD-, LRR- and pyrin domain-containing protein 3) in such injury. RIP3 inhibition prevented the plasma membrane rupture and delayed mPTP opening which was associated with the modulation of xanthin oxidase (XO) and manganese superoxide dismutase (MnSOD). Taken together, this is the first study indicating that RIP3 regulates early reperfusion injury via oxidative stress- and mitochondrial activity-related effects, rather than cell loss due to necroptosis.

Keywords:  myocardial ischemia/reperfusion; necroptosis; receptor-interacting protein kinase 3

DOI:  https://doi.org/10.3390/ijms22157983
Intensive Care Med Exp. 2021 Aug 02. 9(1): 38

Flow-dependent regulation of endothelial Tie2 by GATA3 in vivo.

Temitayo O Idowu, Valerie Etzrodt, Thorben Pape, Joerg Heineke, Klaus Stahl, Hermann Haller, Sascha David.

  BACKGROUND: Reduced endothelial Tie2 expression occurs in diverse experimental models of critical illness, and experimental Tie2 suppression is sufficient to increase spontaneous vascular permeability. Looking for a common denominator among different critical illnesses that could drive the same Tie2 suppressive (thereby leak inducing) phenotype, we identified "circulatory shock" as a shared feature and postulated a flow-dependency of Tie2 gene expression in a GATA3 dependent manner. Here, we analyzed if this mechanism of flow-regulation of gene expression exists in vivo in the absence of inflammation.RESULTS: To experimentally mimic a shock-like situation, we developed a murine model of clonidine-induced hypotension by targeting a reduced mean arterial pressure (MAP) of approximately 50% over 4 h. We found that hypotension-induced reduction of flow in the absence of confounding disease factors (i.e., inflammation, injury, among others) is sufficient to suppress GATA3 and Tie2 transcription. Conditional endothelial-specific GATA3 knockdown (B6-Gata3tm1-Jfz VE-Cadherin(PAC)-cerERT2) led to baseline Tie2 suppression inducing spontaneous vascular leak. On the contrary, the transient overexpression of GATA3 in the pulmonary endothelium (jet-PEI plasmid delivery platform) was sufficient to increase Tie2 at baseline and completely block its hypotension-induced acute drop. On the functional level, the Tie2 protection by GATA3 overexpression abrogated the development of pulmonary capillary leakage.
CONCLUSIONS: The data suggest that the GATA3-Tie2 signaling pathway might play a pivotal role in controlling vascular barrier function and that it is affected in diverse critical illnesses with shock as a consequence of a flow-regulated gene response. Targeting this novel mechanism might offer therapeutic opportunities to treat vascular leakage of diverse etiologies.

Keywords:  Blood flow; Capillary leakage; Hypotension; Permeability; Shock; Vascular leakage

DOI:  https://doi.org/10.1186/s40635-021-00402-x
Front Cardiovasc Med. 2021 ;8 689218

Monocyte Dysfunction Detected by the Designed Ankyrin Repeat Protein F7 Predicts Mortality in Patients Receiving Veno-Arterial Extracorporeal Membrane Oxygenation.

Patrick M Siegel, Lukas Orlean, István Bojti, Klaus Kaier, Thilo Witsch, Jennifer S Esser, Georg Trummer, Martin Moser, Karlheinz Peter, Christoph Bode, Philipp Diehl.

  Background: Veno-arterial extracorporeal membrane oxygenation (VA-ECMO) is used for critically ill patients requiring hemodynamic support but has been shown to induce an inflammatory response syndrome potentially leading to severe complications and poor outcome. Monocytes are comprised of different subsets and play a central role in the innate immune system. The unique small binding proteins, Designed Ankyrin Repeat Protein "F7" and single chain variable fragment "MAN-1," specifically detect the activated conformation of the leukocyte integrin Mac-1 enabling the highly sensitive detection of monocyte activation status. The aim of this study was to characterize monocyte function and heterogeneity and their association with outcome in VA-ECMO patients. Methods: VA-ECMO patients were recruited from the ICUs of the University Hospital in Freiburg, Germany. Blood was sampled on day 0 and day 3 after VA-ECMO placement, after VA-ECMO explantation and from healthy controls. Monocyte subset distribution, baseline activation and stimulability were analyzed by flow cytometry using the unique small binding proteins F7 and MAN-1 and the conventional activation markers CD163, CD86, CD69, and CX3CR1. Furthermore, expression of monocyte activation markers in survivors and non-survivors on day 0 was compared. Simple logistic regression was conducted to determine the association of monocyte activation markers with mortality. Results: Twenty two patients on VA-ECMO and 15 healthy controls were recruited. Eleven patients survived until discharge from the ICU. Compared to controls, baseline monocyte activation was significantly increased, whereas stimulability was decreased. The percentage of classical monocytes increased after explantation, while the percentage of intermediate monocytes decreased. Total, classical, and intermediate monocyte counts were significantly elevated compared to controls. On day 0, baseline binding of F7 was significantly lower in non-survivors than survivors. The area under the ROC curve associated with mortality on day 0 was 0.802 (p = 0.02). Conclusions: Distribution of monocyte subsets changes during VA-ECMO and absolute classical and intermediate monocyte counts are significantly elevated compared to controls. Monocytes from VA-ECMO patients showed signs of dysfunction. Monocyte dysfunction, as determined by the unique tool F7, could be valuable for predicting mortality in patients receiving VA-ECMO and may be used as a novel biomarker guiding early clinical decision making in the future.

Keywords:  DARPin®; Mac-1; activation; extracorporeal membrane oxygenation; inflammation; monocyte

DOI:  https://doi.org/10.3389/fcvm.2021.689218
Sci Rep. 2021 Aug 03. 11(1): 15691

Tracking oxidation-induced alterations in fibrin clot formation by NMR-based methods.

Wai-Hoe Lau, Nathan J White, Tsin-Wen Yeo, Russell L Gruen, Konstantin Pervushin.

Plasma fibrinogen is an important coagulation factor and susceptible to post-translational modification by oxidants. We have reported impairment of fibrin polymerization after exposure to hypochlorous acid (HOCl) and increased methionine oxidation of fibrinogen in severely injured trauma patients. Molecular dynamics suggests that methionine oxidation poses a mechanistic link between oxidative stress and coagulation through protofibril lateral aggregation by disruption of AαC domain structures. However, experimental evidence explaining how HOCl oxidation impairs fibrinogen structure and function has not been demonstrated. We utilized polymerization studies and two dimensional-nuclear magnetic resonance spectrometry (2D-NMR) to investigate the hypothesis that HOCl oxidation alters fibrinogen conformation and T2 relaxation time of water protons in the fibrin gels. We have demonstrated that both HOCl oxidation of purified fibrinogen and addition of HOCl-oxidized fibrinogen to plasma fibrinogen solution disrupted lateral aggregation of protofibrils similarly to competitive inhibition of fibrin polymerization using a recombinant AαC fragment (AαC 419-502). DOSY NMR measurement of fibrinogen protons demonstrated that the diffusion coefficient of fibrinogen increased by 17.4%, suggesting the oxidized fibrinogen was more compact and fast motion in the prefibrillar state. 2D-NMR analysis reflected that water protons existed as bulk water (T2) and intermediate water (T2i) in the control plasma fibrin. Bulk water T2 relaxation time was increased twofold and correlated positively with the level of HOCl oxidation. However, T2 relaxation of the oxidized plasma fibrin gels was dominated by intermediate water. Oxidation induced thinner fibers, in which less water is released into the bulk and water fraction in the hydration shell was increased. We have confirmed that T2 relaxation is affected by the self-assembly of fibers and stiffness of the plasma fibrin gel. We propose that water protons can serve as an NMR signature to probe oxidative rearrangement of the fibrin clot.

DOI: https://doi.org/10.1038/s41598-021-94401-3
Eur J Pharmacol. 2021 Jul 29. pii: S0014-2999(21)00539-2. [Epub ahead of print]909 174386

Pharmacological activation of SIRT1 by metformin prevented trauma-induced heterotopic ossification through inhibiting macrophage mediated inflammation.

Ziyang Sun, Juehong Li, Gang Luo, Weixuan Liu, Yunwei He, Feiyan Wang, Yun Qian, Cunyi Fan.

  Trauma-induced heterotopic ossification (HO) is the aberrant extra-skeletal bone formation that severely incapacitates patient's daily life. Inflammation is the first stage of this progression, becoming an appealing target of early therapeutic intervention. Metformin, a widely used antidiabetic drug, also poses the therapeutic potential to modulate various inflammatory-related diseases. Therefore, this study aimed to investigate the preventive effect of metformin on trauma-induced HO progression, and unveil the underlying molecular mechanisms. A murine burn/tenotomy model was established to mimic trauma-induced HO in vivo. The anti-inflammation and anti-ossification effects of metformin were evaluated by histological staining and micro-CT. The inhibitory effects of metformin on macrophages activation in vitro were examined by ELISA and qRT-PCR. The underlying molecular mechanisms were further explored by immunofluorescence staining and western-blotting in vivo. Increased macrophages infiltration and inflammatory responses were found at early stage during HO progression. However, metformin dose-dependently attenuated the macrophage-mediated inflammatory responses both in vivo and vitro, which might account for the inhibitory effect of metformin on chondrogenesis and HO formation after trauma. Furthermore, elevated SIRT1 expression and decreased NF-κB p65 acetylation were found in the beneficial effects of metformin. Moreover, similar preventive effects were also found in SRT1720 HCI, a specific SIRT1 activator, while were remarkably reversed after the administration of EX527 (a specific SIRT1 inhibitor) with metformin. Taken together, our results provide a novel evidence that metformin can effectively attenuate trauma-induced HO by mitigating macrophage inflammatory responses through inhibiting NF-κB signaling via SIRT1-dependent mechanisms, which favors future therapeutic investigations for trauma-related disease.

Keywords:  Heterotopic ossification; Inflammation; Macrophage; Metformin; NF-κB; SIRT1

DOI:  https://doi.org/10.1016/j.ejphar.2021.174386
Front Cell Dev Biol. 2021 ;9 711003

The Endothelial Glycocalyx as a Double-Edged Sword in Microvascular Homeostasis and Pathogenesis.

Nuria Villalba, Sheon Baby, Sarah Y Yuan.

  Expressed on the endothelial cell (EC) surface of blood vessels, the glycocalyx (GCX), a mixture of carbohydrates attached to proteins, regulates the access of cells and molecules in the blood to the endothelium. Besides protecting endothelial barrier integrity, the dynamic microstructure of the GCX confers remarkable functions including mechanotransduction and control of vascular tone. Recently, a novel perspective has emerged supporting the pleiotropic roles of the endothelial GCX (eGCX) in cardiovascular health and disease. Because eGCX degradation occurs in certain pathological states, the circulating levels of eGCX degradation products have been recognized to have diagnostic or prognostic values. Beyond their biomarker roles, certain eGCX fragments serve as pathogenic factors in disease progression. Pharmacological interventions that attenuate eGCX degradation or restore its integrity have been sought. This review provides our current understanding of eGCX structure and function across the microvasculature in different organs. We also discuss disease or injury states, such as infection, sepsis and trauma, where eGCX dysfunction contributes to severe inflammatory vasculopathy.

Keywords:  endothelium; glycocalyx; inflammation; microvascular homeostasis; permeability

DOI:  https://doi.org/10.3389/fcell.2021.711003
Cells. 2021 Jul 20. pii: 1838. [Epub ahead of print]10(7):

Transcriptomic Hallmarks of Ischemia-Reperfusion Injury.

Mandana Movahed, Sydney Brockie, James Hong, Michael G Fehlings.

  Ischemia reperfusion injury (IRI) is associated with a broad array of life-threatening medical conditions including myocardial infarct, cerebral stroke, and organ transplant. Although the pathobiology and clinical manifestations of IRI are well reviewed by previous publications, IRI-related transcriptomic alterations are less studied. This study aimed to reveal a transcriptomic hallmark for IRI by using the RNA-sequencing data provided by several studies on non-human preclinical experimental models. In this regard, we focused on the transcriptional responses of IRI in an acute time-point up to 48 h. We compiled a list of highly reported genes in the current literature that are affected in the context of IRI. We conducted Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses and found many of the up-regulated genes to be involved in cell survival, cell surface signaling, response to oxidative stress, and inflammatory response, while down-regulated genes were predominantly involved in ion transport. Furthermore, by GO analysis, we found that multiple inflammatory and stress response processes were affected after IRI. Tumor necrosis factor alpha (TNF) and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) signaling pathways were also highlighted in the Kyoto Encyclopedia of Genes and Genomes enrichment analysis. In the last section, we discuss the treatment approaches and their efficacy for IRI by comparing RNA sequencing data from therapeutic interventions with the results of our cross-comparison of differentially expressed genes and pathways across IRI.

Keywords:  RNA-seq; ischemia reperfusion injury; transcriptomics

DOI:  https://doi.org/10.3390/cells10071838
Biomedicines. 2021 Jul 01. pii: 768. [Epub ahead of print]9(7):

The Potential Role of Extracorporeal Cytokine Removal in Hemodynamic Stabilization in Hyperinflammatory Shock.

Fatime Hawchar, Cristina Rao, Ali Akil, Yatin Mehta, Christopher Rugg, Joerg Scheier, Harriet Adamson, Efthymios Deliargyris, Zsolt Molnar.

  Hemodynamic instability due to dysregulated host response is a life-threatening condition requiring vasopressors and vital organ support. Hemoadsorption with Cytosorb has proven to be effective in reducing cytokines and possibly in attenuating the devastating effects of the cytokine storm originating from the immune over-response to the initial insult. We reviewed the PubMed database to assess evidence of the impact of Cytosorb on norepinephrine needs in the critically ill. We further analyzed those studies including data on control cohorts in a comparative pooled analysis, defining a treatment effect as the standardized mean differences in relative reductions in vasopressor dosage at 24 h. The literature search returned 33 eligible studies. We found evidence of a significant reduction in norepinephrine requirement after treatment: median before, 0.55 (IQR: 0.39-0.90); after, 0.09 (0.00-0.25) μg/kg/min, p < 0.001. The pooled effect size at 24 h was large, though characterized by high heterogeneity. In light of the importance of a quick resolution of hemodynamic instability in the critically ill, further research is encouraged to enrich knowledge on the potentials of the therapy.

Keywords:  cytosorb therapy; decatecholaminization; hemoadsorption; hemodynamic stabilization; hypeinflammation; shock

DOI:  https://doi.org/10.3390/biomedicines9070768
Biomedicines. 2021 Jul 06. pii: 781. [Epub ahead of print]9(7):

Inflammatory Mechanisms Contributing to Endothelial Dysfunction.

Panagiotis Theofilis, Marios Sagris, Evangelos Oikonomou, Alexios S Antonopoulos, Gerasimos Siasos, Costas Tsioufis, Dimitris Tousoulis.

  Maintenance of endothelial cell integrity is an important component of human health and disease since the endothelium can perform various functions including regulation of vascular tone, control of hemostasis and thrombosis, cellular adhesion, smooth muscle cell proliferation, and vascular inflammation. Endothelial dysfunction is encompassed by complex pathophysiology that is based on endothelial nitric oxide synthase uncoupling and endothelial activation following stimulation from various inflammatory mediators (molecular patterns, oxidized lipoproteins, cytokines). The downstream signaling via nuclear factor-κB leads to overexpression of adhesion molecules, selectins, and chemokines that facilitate leukocyte adhesion, rolling, and transmigration to the subendothelial space. Moreover, oscillatory shear stress leads to pro-inflammatory endothelial activation with increased monocyte adhesion and endothelial cell apoptosis, an effect that is dependent on multiple pathways and flow-sensitive microRNA regulation. Moreover, the role of neutrophil extracellular traps and NLRP3 inflammasome as inflammatory mechanisms contributing to endothelial dysfunction has recently been unveiled and is under further investigation. Consequently, and following their activation, injured endothelial cells release inflammatory mediators and enter a pro-thrombotic state through activation of coagulation pathways, downregulation of thrombomodulin, and an increase in platelet adhesion and aggregation owing to the action of von-Willebrand factor, ultimately promoting atherosclerosis progression.

Keywords:  NLRP3 inflammasome; Nf-κB; adhesion molecules; endothelial dysfunction; inflammation; selectins; shear stress

DOI:  https://doi.org/10.3390/biomedicines9070781
Int J Mol Sci. 2021 Jul 21. pii: 7770. [Epub ahead of print]22(15):

Emerging Approaches to Understanding Microvascular Endothelial Heterogeneity: A Roadmap for Developing Anti-Inflammatory Therapeutics.

Qingliang Yang, Harshani Wijerathne, Jordan C Langston, Mohammad F Kiani, Laurie E Kilpatrick.

  The endothelium is the inner layer of all blood vessels and it regulates hemostasis. It also plays an active role in the regulation of the systemic inflammatory response. Systemic inflammatory disease often results in alterations in vascular endothelium barrier function, increased permeability, excessive leukocyte trafficking, and reactive oxygen species production, leading to organ damage. Therapeutics targeting endothelium inflammation are urgently needed, but strong concerns regarding the level of phenotypic heterogeneity of microvascular endothelial cells between different organs and species have been expressed. Microvascular endothelial cell heterogeneity in different organs and organ-specific variations in endothelial cell structure and function are regulated by intrinsic signals that are differentially expressed across organs and species; a result of this is that neutrophil recruitment to discrete organs may be regulated differently. In this review, we will discuss the morphological and functional variations in differently originated microvascular endothelia and discuss how these variances affect systemic function in response to inflammation. We will review emerging in vivo and in vitro models and techniques, including microphysiological devices, proteomics, and RNA sequencing used to study the cellular and molecular heterogeneity of endothelia from different organs. A better understanding of microvascular endothelial cell heterogeneity will provide a roadmap for developing novel therapeutics to target the endothelium.

Keywords:  bMFA; endothelial barrier permeability; heterogeneity; inflammation; leukocytes; microphysiological systems; microvascular endothelial cells; protein kinase Cδ; sepsis; transmigration

DOI:  https://doi.org/10.3390/ijms22157770
Cells. 2021 Jul 03. pii: 1680. [Epub ahead of print]10(7):

Myostatin Deficiency Protects C2C12 Cells from Oxidative Stress by Inhibiting Intrinsic Activation of Apoptosis.

Marius Drysch, Sonja Verena Schmidt, Mustafa Becerikli, Felix Reinkemeier, Stephanie Dittfeld, Johannes Maximilian Wagner, Mehran Dadras, Alexander Sogorski, Maxi von Glinski, Marcus Lehnhardt, Björn Behr, Christoph Wallner.

  Ischemia reperfusion (IR) injury remains an important topic in clinical medicine. While a multitude of prophylactic and therapeutic strategies have been proposed, recent studies have illuminated protective effects of myostatin inhibition. This study aims to elaborate on the intracellular pathways involved in myostatin signaling and to explore key proteins that convey protective effects in IR injury. We used CRISPR/Cas9 gene editing to introduce a myostatin (Mstn) deletion into a C2C12 cell line. In subsequent experiments, we evaluated overall cell death, activation of apoptotic pathways, ROS generation, lipid peroxidation, intracellular signaling via mitogen-activated protein kinases (MAPKs), cell migration, and cell proliferation under hypoxic conditions followed by reoxygenation to simulate an IR situation in vitro (hypoxia reoxygenation). It was found that mitogen-activated protein kinase kinase 3/6, also known as MAPK/ERK Kinase 3/6 (MEK3/6), and subsequent p38 MAPK activation were blunted in C2C12-Mstn-/- cells in response to hypoxia reoxygenation (HR). Similarly, c-Jun N-terminal kinase (JNK) activation was negated. We also found the intrinsic activation of apoptosis to be more important in comparison with the extrinsic activation. Additionally, intercepting myostatin signaling mitigated apoptosis activation. Ultimately, this research validated protective effects of myostatin inhibition in HR and identified potential mediators worth further investigation. Intercepting myostatin signaling did not inhibit ROS generation overall but mitigated cellular injury. In particular, intrinsic activation of apoptosis origination from mitochondria was alleviated. This was presumably mediated by decreased activation of p38 caused by the diminished kinase activity increase of MEK3/6. Overall, this work provides important insights into HR signaling in C2C12-Mstn-/- cells and could serve as basis for further research.

Keywords:  GDF8; hypoxia; ischemia; muscle; myostatin; reoxygenation; reperfusion; skeletal

DOI:  https://doi.org/10.3390/cells10071680
Physiol Rep. 2021 Aug;9(15): e14953

Regional thermal hyperemia in the human leg: Evidence of the importance of thermosensitive mechanisms in the control of the peripheral circulation.

Nuno Koch Esteves, Oliver R Gibson, Ashraf W Khir, José González-Alonso.

  Hyperthermia is thought to increase limb blood flow through the activation of thermosensitive mechanisms within the limb vasculature, but the precise vascular locus in which hyperthermia modulates perfusion remains elusive. We tested the hypothesis that local temperature-sensitive mechanisms alter limb hemodynamics by regulating microvascular blood flow. Temperature and oxygenation profiles and leg hemodynamics of the common (CFA), superficial (SFA) and profunda (PFA) femoral arteries, and popliteal artery (POA) of the experimental and control legs were measured in healthy participants during: (1) 3 h of whole leg heating (WLH) followed by 3 h of recovery (n = 9); (2) 1 h of upper leg heating (ULH) followed by 30 min of cooling and 1 h ULH bout (n = 8); and (3) 1 h of lower leg heating (LLH) (n = 8). WLH increased experimental leg temperature by 4.2 ± 1.2ºC and blood flow in CFA, SFA, PFA, and POA by ≥3-fold, while the core temperature essentially remained stable. Upper and lower leg blood flow increased exponentially in response to leg temperature and then declined during recovery. ULH and LLH similarly increased the corresponding segmental leg temperature, blood flow, and tissue oxygenation without affecting these responses in the non-heated leg segment, or perfusion pressure and conduit artery diameter across all vessels. Findings demonstrate that whole leg hyperthermia induces profound and sustained elevations in upper and lower limb blood flow and that segmental hyperthermia matches the regional thermal hyperemia without causing thermal or hemodynamic alterations in the non-heated limb segment. These observations support the notion that heat-activated thermosensitive mechanisms in microcirculation regulate limb tissue perfusion during hyperthermia.

Keywords:  blood flow; heat; hemodynamics; thermal mechanisms

DOI:  https://doi.org/10.14814/phy2.14953