Evaluation of resuscitation fluids on endothelial glycocalyx, venular blood flow, and coagulation function after hemorrhagic shock in rats

Retrospective evaluation of plasma transfusions in dogs undergoing general anaesthesia: 85 cases (2017-2021)

OBJECTIVE

To describe the use of plasma transfusion in anaesthetized dogs, specifically the triggers for use, the population administered plasma, reported adverse events and human errors associated with transfusion.

STUDY DESIGN

Retrospective observational study.

ANIMALS

A total of 85 client-owned dogs.

METHODS

A search of electronic transfusion and anaesthetic records at a university teaching hospital was performed to identify dogs administered plasma during the study period (January 2017 to June 2021). Data collected included signalment, surgical procedure, intraoperative triggers for transfusion, the type of plasma, rate of transfusion and the presence of transfusion reactions, human errors or deviation from transfusion guidelines.

RESULTS

During this period, 85 dogs were administered plasma. Sepsis was diagnosed in 49/85 (58%) dogs, with 42/85 (49%) animals undergoing surgery for septic peritonitis. Perianaesthetic hypotension contributed to the decision to administer plasma in 67/85 (79%) dogs. In 33/85 (39%) dogs, hypotension was the only reason for transfusion, while 31/85 (36%) had other influencing factors, most commonly hypoproteinaemia. Fresh frozen plasma was administered in 95% of cases. Only 31% of transfusions were started at a slower 'test dose' rate and 79% of dogs administered boluses of plasma. No definite, probable or possible transfusion reactions were identified using current veterinary guidelines.

CONCLUSIONS AND CLINICAL RELEVANCE

Plasma transfusions were commonly administered to dogs presenting with sepsis for haemodynamic optimization. Clinicians often chose to bolus plasma instead of initiating transfusions at the recommended initial slow starting rate. No transfusion reactions were identified; however, some reactions may have been masked by the effects of general anaesthesia and/or have been difficult to recognize in this critically ill canine population.

Endothelial dysfunction is dampened by early administration of fresh frozen plasma in a rodent burn shock model

BACKGROUND

Endothelial dysfunction has been implicated in the pathogenesis of burn shock affecting patients with large thermal injury. In response to injury, glycocalyx components like Syndecan-1 (SDC-1) are shed into circulation and have been used as markers of endothelial damage. Previous work in our laboratory has shown that plasma inclusive resuscitation (PIR) with fresh frozen plasma (FFP) ameliorates endothelial damage. However, there remains a paucity of information regarding optimal timing and dosing of PIR as well as organ-specific endothelial responses to shock. We aimed to examine the impact of PIR on endothelial dysfunction using clinically translatable timing and dosing.

METHODS

Sprague-Dawley rats were used to create thermal burns. Rats were subjected to 40% total body surface area scald burns and were resuscitated with lactated Ringer's (LR) only, LR plus albumin, and LR plus early 1 mL boluses of FFP at 0, 2, 4, and 8 hours postinjury. A late group also received LR plus FFP starting at hour 10 postinjury. Syndecan-1 levels were quantified by enzyme-linked immunosorbent assay, and quantitative real-time polymerase chain reaction analysis characterized transcription of glycocalyx components and inflammatory cytokines in the lung and spleen. Evan's blue dye was used to quantify amount of vascular leakage.

RESULTS

Lactated Ringer's plus early FFP reduced Evan's blue dye extravasation when compared with LR only groups, while late FFP did not. When comparing LR only versus LR plus early FFP, SDC-1 levels were reduced in the LR plus early FFP group at hours 8, 12, and 24 (5.23 vs. 2.07, p < 0.001; 4.49 vs. 2.05, p < 0.01; and 3.82 vs. 2.08, p < 0.05, respectively). Lactated Ringer's only groups had upregulation of Exostosin-1 and SDC-1 in the lung compared with LR plus early FFP groups ( p < 0.01 and p < 0.05) and upregulation of cytokines interluekin-10 and interferon γ ( p < 0.001 and p < 0.001).

CONCLUSION

Early administration of LR plus FFP reduces the magnitude of SDC-1 shedding and dampens the cytokine response to injury. The upregulation of glycocalyx components as a response to endothelial injury is also decreased in the lung and spleen by LR plus early FFP administration.

Plasma for prevention and treatment of glycocalyx degradation in trauma and sepsis

The endothelial glycocalyx, a gel-like layer that lines the luminal surface of blood vessels, is composed of proteoglycans, glycoproteins, and glycosaminoglycans. The endothelial glycocalyx plays an essential role in vascular homeostasis, and its degradation in trauma and sepsis can lead to microvascular dysfunction and organ injury. While there are no proven therapies for preventing or treating endothelial glycocalyx degradation, some initial literature suggests that plasma may have a therapeutic role in trauma and sepsis patients. Overall, the literature suggesting the use of plasma as a therapy for endothelial glycocalyx degradation is non-clinical basic science or exploratory. Plasma is an established therapy in the resuscitation of patients with hemorrhage for restoration of coagulation factors. However, plasma also contains other bioactive components, including sphingosine-1 phosphate, antithrombin, and adiponectin, which may protect and restore the endothelial glycocalyx, thereby helping to maintain or restore vascular homeostasis. This narrative review begins by describing the endothelial glycocalyx in health and disease: we discuss the overlapping disease mechanisms in trauma and sepsis that lead to its damage and introduce plasma transfusion as a potential therapy for prevention and treatment of endothelial glycocalyx degradation. Second, we review the literature on plasma as an exploratory therapy for endothelial glycocalyx degradation in trauma and sepsis. Third, we discuss the safety of plasma transfusion by reviewing the adverse events associated with plasma and other blood product transfusions, and we examine modern transfusion precautions that have enhanced the safety of plasma transfusion. We conclude that the literature proposes that plasma may have the potential to prevent and treat endothelial glycocalyx degradation in trauma and sepsis, indicating the need for further research.

Prothrombin and activated partial thromboplastin times, thromboelastography, hematocrit, and platelet count in a feline hemorrhage/over-resuscitation model using lactated Ringer's solution or 6% tetrastarch 130/0.4

OBJECTIVE

To describe and compare prothrombin time (PT), activated partial thromboplastin time (aPTT), thromboelastography (TEG), HCT, and platelet count measurements in a hemorrhage/over-resuscitation model.

DESIGN

Randomized crossover study.

SETTING

University teaching hospital.

ANIMALS

Six cats.

INTERVENTIONS

Anesthetized cats underwent 3 treatments at 2-month intervals. The treatments were as follows: NHR-no controlled hemorrhage and sham resuscitation; LRS-controlled hemorrhage and lactated Ringer's solution (LRS) for resuscitation; and Voluven-controlled hemorrhage and 6% tetrastarch 130/0.4 for resuscitation. The LRS and Voluven were administered at 60 and 20 mL/kg/h, respectively, for 120 minutes. Blood samples were drawn for PT, aPTT, TEG, HCT, and platelet count measurements at a healthy check (T - 7d), after controlled hemorrhage (T0), at 60 and 120 minutes of resuscitation (T60 and T120), and at 24 hours after completion of resuscitation (T24h). Data were analyzed using a general linear mixed model approach (significance was P < 0.05).

MEASUREMENTS AND MAIN RESULTS

Total median blood loss (controlled hemorrhage and blood sampling from T0 to T120) at T120 was 11.4, 31.0, and 30.8 mL/kg for NHR, LRS, and Voluven, respectively. PT and aPTT during LRS and Voluven were prolonged at T60 and T120 compared to NHR (P < 0.001). On TEG, the reaction time, kinetic time, and alpha-angle were within reference intervals for cats at all time points in all treatments, while maximum amplitude was less than the reference interval (40 mm) at T0, T60, and T120 during Voluven and at T60 and T120 during LRS compared to NHR (both P < 0.001). The HCT and platelet count were significantly lower at T60 and T120 during LRS and Voluven compared to NHR (P < 0.001).

CONCLUSIONS

Hypocoagulopathy was observed during hemorrhage and liberal fluid resuscitation. Prolongation of PT and aPPT and decreased clot strength may have been caused by hemodilution and platelet loss.

Activation of cardiac parasympathetic and sympathetic activity occurs at different skin temperatures during face cooling

Sufficiently cold-water temperatures (<7°C) are needed to elicit the sympathetic response to the cold pressor test using the hand. However, it is not known if stimulating the trigeminal nerve via face cooling, which increases both sympathetic and cardiac parasympathetic activity, also has a threshold temperature. We tested the hypothesis that peak autonomic activation during a progressive face cooling challenge would be achieved when the stimulus temperature is ≤7°C. Twelve healthy participants (age: 25 ± 3 yr, four women) completed our study. Six pliable bags, each containing water or an ice slurry (34°C, 28°C, 21°C, 14°C, 7°C, and 0°C) were applied sequentially to participants' forehead, eyes, and cheeks for 5 min each. Mean arterial pressure (photoplethysmography; index of sympathetic activity) and heart rhythm (3-lead ECG) were averaged in 1-min increments at the end of baseline and throughout each temperature condition. Heart rate variability in the time [(root mean square of successive differences (RMSSD)] and frequency [high-frequency (HF) power] domains was used to estimate cardiac parasympathetic activity. Data are presented as the increase from baseline ± SD. Mean arterial pressure only increased from baseline in the 7°C (13.1 ± 10.3 mmHg; P = 0.018) and 0°C (25.2 ± 7.8 mmHg; P < 0.001) conditions. Only the 0°C condition increased RMSSD (160.6 ± 208.9 ms; P = 0.009) and HF power (11,450 ± 14,555 ms2; P = 0.014) from baseline. Our data indicate that peak increases in sympathetic activity during face cooling are initiated at a higher forehead skin temperature than peak increases in cardiac parasympathetic activity.

Managing sepsis and septic shock in an endothelial glycocalyx-friendly way: from the viewpoint of surviving sepsis campaign guidelines

Maintaining tissue perfusion in sepsis depends on vascular integrity provided by the endothelial glycocalyx, the critical layer covering the luminal surface of blood vessels. The glycocalyx is composed of proteoglycans, glycosaminoglycans, and functional plasma proteins that are critical for antithrombogenicity, regulating tone, controlling permeability, and reducing endothelial interactions with leukocytes and platelets. Degradation of the glycocalyx in sepsis is substantial due to thromboinflammation, and treatments for sepsis and septic shock may exacerbate endotheliopathy via additional glycocalyx injury. As a result, therapeutic strategies aimed at preserving glycocalyx integrity should be considered, including modifications in fluid volume resuscitation, minimizing catecholamine use, controlling hyperglycemia, and potential use of corticosteroids and anticoagulants. In this review, we explore treatment strategies aligned with the recommendations outlined in the Surviving Sepsis Campaign Guidelines 2021 with a special emphasis on evidence regarding glycocalyx protection.

Impact of COVID status and blood group on complications in patients in hemorrhagic shock

Objective

Among critically injured patients of various blood groups, we sought to compare survival and complication rates between COVID-19-positive and COVID-19-negative cohorts.

Background

SARS-CoV-2 infections have been shown to cause endothelial injury and dysfunctional coagulation. We hypothesized that, among patients with trauma in hemorrhagic shock, COVID-19-positive status would be associated with increased mortality and inpatient complications. As a secondary hypothesis, we suspected group O patients with COVID-19 would experience fewer complications than non-group O patients with COVID-19.

Methods

We evaluated all trauma patients admitted 4/2020-7/2020. Patients 16 years or older were included if they presented in hemorrhagic shock and received emergency release blood products. Patients were dichotomized by COVID-19 testing and then divided by blood groups.

Results

3281 patients with trauma were evaluated, and 417 met criteria for analysis. Seven percent (29) of patients were COVID-19 positive; 388 were COVID-19 negative. COVID-19-positive patients experienced higher complication rates than the COVID-19-negative cohort, including acute kidney injury, pneumonia, sepsis, venous thromboembolism, and systemic inflammatory response syndrome. Univariate analysis by blood groups demonstrated that survival for COVID-19-positive group O patients was similar to that of COVID-19-negative patients (79 vs 78%). However, COVID-19-positive non-group O patients had a significantly lower survival (38%). Controlling for age, sex and Injury Severity Score, COVID-19-positive patients had a greater than 70% decreased odds of survival (OR 0.28, 95% CI 0.09 to 0.81; p=0.019).

Conclusions

COVID-19 status is associated with increased major complications and 70% decreased odds of survival in this group of patients with trauma. However, among patients with COVID-19, blood group O was associated with twofold increased survival over other blood groups. This survival rate was similar to that of patients without COVID-19.

Contemporary management of major haemorrhage in critical care

Haemorrhagic shock is frequent in critical care settings and responsible for a high mortality rate due to multiple organ dysfunction and coagulopathy. The management of critically ill patients with bleeding and shock is complex, and treatment of these patients must be rapid and definitive. The administration of large volumes of blood components leads to major physiological alterations which must be mitigated during and after bleeding. Early recognition of bleeding and coagulopathy, understanding the underlying pathophysiology related to specific disease states, and the development of individualised management protocols are important for optimal outcomes. This review describes the contemporary understanding of the pathophysiology of various types of coagulopathic bleeding; the diagnosis and management of critically ill bleeding patients, including major haemorrhage protocols and post-transfusion management; and finally highlights recent areas of opportunity to better understand optimal management strategies for managing bleeding in the intensive care unit (ICU).

THE NEUROENDOTHELIAL AXIS IN TRAUMATIC BRAIN INJURY: MECHANISMS OF MULTIORGAN DYSFUNCTION, NOVEL THERAPIES, AND FUTURE DIRECTIONS

ABSTRACT

Severe traumatic brain injury (TBI) often initiates a systemic inflammatory response syndrome, which can potentially culminate into multiorgan dysfunction. A central player in this cascade is endotheliopathy, caused by perturbations in homeostatic mechanisms governed by endothelial cells due to injury-induced coagulopathy, heightened sympathoadrenal response, complement activation, and proinflammatory cytokine release. Unique to TBI is the potential disruption of the blood-brain barrier, which may expose neuronal antigens to the peripheral immune system and permit neuroinflammatory mediators to enter systemic circulation, propagating endotheliopathy systemically. This review aims to provide comprehensive insights into the "neuroendothelial axis" underlying endothelial dysfunction after TBI, identify potential diagnostic and prognostic biomarkers, and explore therapeutic strategies targeting these interactions, with the ultimate goal of improving patient outcomes after severe TBI.

Association between intravenous fluid administration and endothelial glycocalyx shedding in humans: a systematic review

INTRODUCTION

Several studies have demonstrated associations between greater rate/volume of intravenous (IV) fluid administration and poorer clinical outcomes. One postulated mechanism for harm from exogenous fluids is shedding of the endothelial glycocalyx (EG).

METHODS

A systematic review using relevant search terms was performed using Medline, EMBASE and Cochrane databases from inception to October 2023. Included studies involved humans where the exposure was rate or volume of IV fluid administration and the outcome was EG shedding. The protocol was prospectively registered on PROSPERO: CRD42021275133.

RESULTS

The search yielded 450 articles, with 20 articles encompassing 1960 participants included in the review. Eight studies were randomized controlled clinical trials. Half of studies examined patients with sepsis and critical illness; the remainder examined perioperative patients or healthy subjects. Almost all reported blood measurements of soluble EG components; one study used in vivo video-microscopy to estimate EG thickness. Four of 10 sepsis studies, and 9 of 11 non-sepsis studies, found a positive relationship between IV fluid rate/volume and measures of EG shedding.

CONCLUSIONS

A trend toward an association between IV fluid rate/volume and EG shedding was found in studies of stable patients, but was not consistently observed among studies of septic and critically ill patients.

Microvascular Endothelial Glycocalyx Surface Layer Visualization and Quantification

As a primary interface between the blood and underlying vascular wall, the endothelial glycocalyx layer is common to all blood vessels and covers the luminal surface of all endothelial cells. The endothelial glycocalyx has important roles as a regulator of microvascular endothelial functions such as mechanotransduction, leukocyte adhesion, and microvascular permeability. Disruption of the molecular structure of the endothelial glycocalyx disturbs physiological, and hemodynamic processes associated with the microvascular wall leads to microvascular hyperpermeability. Studying the glycocalyx is challenging because cultured cells present aberrant glycocalyx structure and tissue fixation techniques lead to the degradation and loss of this fine and delicate layer. Therefore, studying the glycocalyx requires in vivo imaging of the microcirculation. Here we describe two techniques for direct imaging and assessment of the glycocalyx surface layer integrity using intravital microscopy (IVM), a method widely used in the study of the dynamic changes that occur in the microcirculation during inflammation or injury.

Shear Stress and Endothelial Mechanotransduction in Trauma Patients with Hemorrhagic Shock: Hidden Coagulopathy Pathways and Novel Therapeutic Strategies

Massive trauma remains a leading cause of death and a global public health burden. Post-traumatic coagulopathy may be present even before the onset of resuscitation, and correlates with severity of trauma. Several mechanisms have been proposed to explain the development of abnormal coagulation processes, but the heterogeneity in injuries and patient profiles makes it difficult to define a dominant mechanism. Regardless of the pattern of death, a significant role in the pathophysiology and pathogenesis of coagulopathy may be attributed to the exposure of endothelial cells to abnormal physical forces and mechanical stimuli in their local environment. In these conditions, the cellular responses are translated into biochemical signals that induce/aggravate oxidative stress, inflammation, and coagulopathy. Microvascular shear stress-induced alterations could be treated or prevented by the development and use of innovative pharmacologic strategies that effectively target shear-mediated endothelial dysfunction, including shear-responsive drug delivery systems and novel antioxidants, and by targeting the venous side of the circulation to exploit the beneficial antithrombogenic profile of venous endothelial cells.

Effect of high-dose intravenous ascorbic acid on microcirculation and endothelial glycocalyx during sepsis and septic shock: a double-blind, randomized, placebo-controlled study

Previous studies indicate supplemental vitamin C improves microcirculation and reduces glycocalyx shedding in septic animals. Our randomized, double-blind, placebo-controlled trial aimed to investigate whether a high dose of intravenous ascorbic acid (AA) might improve microcirculation and affect glycocalyx in septic patients. In our study, 23 septic patients were supplemented with a high dose (50 mg/kg every 6 h) of intravenous AA or placebo for 96 h. Sublingual microcirculation was examined using a handheld Cytocam-incident dark field (IDF) video microscope. A sidestream dark field video microscope (SDF), connected to the GlycoCheck software (GlycoCheck ICU®; Maastricht University Medical Center, Maastricht, the Netherlands), was employed to observe glycocalyx. We found a significantly higher proportion of perfused small vessels (PPV) 6 h after the beginning of the trial in the experimental group compared with placebo. As an indicator of glycocalyx thickness, the perfused boundary region was lower in capillaries of the 5-9 μm diameter in the AA group than placebo after the first dose of AA. Our data suggest that high-dose parenteral AA tends to improve microcirculation and glycocalyx in the early period of septic shock. The study was retrospectively registered in the clinicaltrials.gov database on 26/02/2021 (registration number NCT04773717).

Resuscitating the Endothelial Glycocalyx in Trauma and Hemorrhagic Shock

The endothelium is lined by a protective mesh of proteins and carbohydrates called the endothelial glycocalyx (EG). This layer creates a negatively charged gel-like barrier between the vascular environment and the surface of the endothelial cell. When intact the EG serves multiple functions, including mechanotransduction, cell signaling, regulation of permeability and fluid exchange across the microvasculature, and management of cell-cell interactions. In trauma and/or hemorrhagic shock, the glycocalyx is broken down, resulting in the shedding of its individual components. The shedding of the EG is associated with increased systemic inflammation, microvascular permeability, and flow-induced vasodilation, leading to further physiologic derangements. Animal and human studies have shown that the greater the severity of the injury, the greater the degree of shedding, which is associated with poor patient outcomes. Additional studies have shown that prioritizing certain resuscitation fluids, such as plasma, cryoprecipitate, and whole blood over crystalloid shows improved outcomes in hemorrhaging patients, potentially through a decrease in EG shedding impacting downstream signaling. The purpose of the following paragraphs is to briefly describe the EG, review the impact of EG shedding and hemorrhagic shock, and begin entertaining the notion of directed resuscitation. Directed resuscitation emphasizes transitioning from macroscopic 1:1 resuscitation to efforts that focus on minimizing EG shedding and maximizing its reconstitution.

Blood component resuscitative strategies to mitigate endotheliopathy in a murine hemorrhagic shock model

BACKGROUND

Resuscitation with plasma components has been shown to improve endotheliopathy induced by hemorrhagic shock, but the optimal resuscitation strategy to preserve the endothelial glycocalyx has yet to be defined. The aim of this study was to determine if resuscitation with lactated Ringer's (LR), whole blood (WB), packed red blood cells (RBCs), platelet-rich plasma (PRP), platelet poor plasma, balanced RBC:PRP (1:1), or day 14 (d14) RBC would best minimize endothelial damage following shock.

METHODS

Male C57BL/6 mice were hemorrhaged to a goal mean arterial pressure of 25 mm Hg for 1 hour. Unshocked sham mice served as controls. Mice were then resuscitated with equal volumes of LR, WB, RBC, PRP, platelet poor plasma, 1:1, or d14 RBC and then sacrificed at 1, 4, or 24 hours (n = 5). Serum was analyzed for syndecan-1, ubiquitin C-terminal hydrolase L1, and cytokine concentrations. Lungs underwent syndecan-1 immunostaining, and lung injury scores were calculated after hematoxylin and eosin. Proteolytic cleavage of the endothelial glycocalyx was assessed by serum matrix metalloprotease 9 levels.

RESULTS

Serum syndecan-1 and ubiquitin C-terminal hydrolase L1 levels were significantly increased following resuscitation with d14 RBC compared with other groups. Early elevation in lung syndecan-1 staining was noted in LR-treated mice, while d14 mice showed decreased staining compared with sham mice following shock. Lung injury scores were significantly elevated 4 hours after resuscitation with LR and d14 RBC compared with WB. Serum matrix metalloprotease 9 levels were significantly increased at 1 and 4 hours in d14 mice compared with sham mice. Systemic inflammation was increased in animals receiving LR, 1:1, or d14 RBC.

CONCLUSION

Resuscitation with WB following hemorrhagic shock reduces endothelial syndecan-1 shedding and mitigates lung injury. Aged RBC and LR fail to attenuate endothelial injury following hemorrhagic shock. Further research will be necessary to determine the effect of each of these resuscitative fluids in a hemorrhagic shock model with the addition of tissue injury.

Endothelial Dysfunction in Patients Undergoing Cardiac Surgery: A Narrative Review and Clinical Implications

Cardiac surgery is one of the highest-risk procedures, usually involving cardiopulmonary bypass and commonly inducing endothelial injury that contributes to the development of perioperative and postoperative organ dysfunction. Substantial scientific efforts are being made to unravel the complex interaction of biomolecules involved in endothelial dysfunction to find new therapeutic targets and biomarkers and to develop therapeutic strategies to protect and restore the endothelium. This review highlights the current state-of-the-art knowledge on the structure and function of the endothelial glycocalyx and mechanisms of endothelial glycocalyx shedding in cardiac surgery. Particular emphasis is placed on potential strategies to protect and restore the endothelial glycocalyx in cardiac surgery. In addition, we have summarized and elaborated the latest evidence on conventional and potential biomarkers of endothelial dysfunction to provide a comprehensive synthesis of crucial mechanisms of endothelial dysfunction in patients undergoing cardiac surgery, and to highlight their clinical implications.

Alterations in heparan sulfate proteoglycan synthesis and sulfation and the impact on vascular endothelial function

The glycocalyx attached to the apical surface of vascular endothelial cells is a rich network of proteoglycans, glycosaminoglycans, and glycoproteins with instrumental roles in vascular homeostasis. Given their molecular complexity and ability to interact with the intra- and extracellular environment, heparan sulfate proteoglycans uniquely contribute to the glycocalyx's role in regulating endothelial permeability, mechanosignaling, and ligand recognition by cognate cell surface receptors. Much attention has recently been devoted to the enzymatic shedding of heparan sulfate proteoglycans from the endothelial glycocalyx and its impact on vascular function. However, other molecular modifications to heparan sulfate proteoglycans are possible and may have equal or complementary clinical significance. In this narrative review, we focus on putative mechanisms driving non-proteolytic changes in heparan sulfate proteoglycan expression and alterations in the sulfation of heparan sulfate side chains within the endothelial glycocalyx. We then discuss how these specific changes to the endothelial glycocalyx impact endothelial cell function and highlight therapeutic strategies to target or potentially reverse these pathologic changes.

The Efficacy of Albumin Channa Striata Extract Administration in Stabilizing PAI-1 and Platelet Levels in Septic Patients: A Randomized Control Trial Study

BACKGROUND: Recently, sepsis has become a serious problem worldwide. There are many studies trying to find the etiologies of morbidity and mortality of sepsis. One of them is the damage of endothelial glycocalyx layer, which can lead to an increase in plasminogen activator inhibitor-1 (PAI-1) level and a decrease in platelets. This damage can be prevented by administering albumin; unfortunately, it is costly. Therefore, an alternative albumin is required. Channa striata extract albumin has been found to be relatively effective in increasing serum albumin levels. However, studies on its effectiveness are still limited. Hence, we analyzed this channa striata extract albumin in stabilizing PAI-1 and platelet levels of septic patients. AIM: This study analyzed channa striata extract albumin in stabilizing PAI-1 and platelet levels of septic patients. METHODS: We conducted a randomized control experimental study in patients with sepsis hospitalized at Dr Moewardi Hospital, Surakarta, Indonesia. The samples were taken by consecutive sampling technique. These patients were allocated into two groups, the albumin extract of channa striata, and human albumin 20% (the control) groups. We examined the PAI-1 and platelet levels on the 1st and 3rd days. We used Mann–Whitney test for statistical analysis with p < 0.05 was considered significant. RESULTS: There were 21 subjects in each group of channa striata (study) and human albumin (control). The increase of PAI-1 level in the study group (0.36 ng/ml) was lower than that of in control group (0.72 ng/ml). More subjects in study group experienced decreased PAI-1 level (n = 5) than those in control group (n = 3), the decrease more profound in control group (p = 0.004) than study group (p = 0.054). The decrease of platelet level was also greater in study group (22 × 103/mcl) than that of in control group (1 × 103.md) despite insignificant difference (p = 0.364 and p = 0.468). CONCLUSION: The administration of channa striata extract effective in stabilizing PAI-1 level in sepsis patient and also had potential benefit as human albumin in stabilizing platelet levels of septic patients.

Fingolimod does not prevent syndecan-4 shedding from the endothelial glycocalyx in a cultured human umbilical vein endothelial cell model of vascular injury

Background

Shedding of the endothelial glycocalyx (EG) is associated with poor outcomes in a range of conditions including sepsis. Fresh frozen plasma (FFP) restores the damaged EG to baseline thickness, however the mechanism for this effect is unknown, and some components of FFP have adverse effects unrelated to the EG. There is some limited evidence that sphingosine-1-phosphate (S1P) within FFP restores the EG by activating the endothelial cell S1P receptor 1 (S1PR₁). However, there are disadvantages to using S1P clinically as an EG restorative therapy. A potential alternative is the S1PR agonist fingolimod (FTY720). The aim of this study was to assess whether FTY720 prevents EG shedding in injured cultured human umbilical vein endothelial cells.

Methods

Shedding of the EG was induced in cultured human umbilical vein endothelial cells (HUVECs) by exposure to adrenaline, TNF-α and H₂O₂. The cells were then assigned to one of six conditions for 4 h: uninjured and untreated, injured and untreated, injured and treated with FTY720 with and without the S1PR₁ inhibitor W146, and injured and treated with 25% FFP with and without W146. Syndecan-4, a component of the EG, was measured in cell supernatants, and syndecan-4 and thrombomodulin mRNA expression was quantitated in cell lysates.

Results

The injury resulted in a 2.1-fold increase in syndecan-4 (p < 0.001), consistent with EG shedding. Syndecan-4 and thrombomodulin mRNA expression was increased (p < 0.001) and decreased (p < 0.05), respectively, by the injury. Syndecan-4 shedding was not affected by treatment with FTY720, whereas FFP attenuated syndecan-4 shedding back to baseline levels in the injured cells and this was unaffected by W146. Neither treatment affected syndecan-4 or thrombomodulin mRNA expression.

Conclusions

FTY720 did not prevent syndecan-4 shedding from the EG in the HUVEC model of endothelial injury, suggesting that activation of S1PR does not prevent EG damage. FFP prevented syndecan-4 shedding from the EG via a mechanism that was independent of S1PR₁ and upregulation of SDC-4 production. Further studies to examine whether FTY720 or another S1PR agonist might have EG-protective effects under different conditions are warranted, as are investigations seeking the mechanism of EG protection conferred by FFP in this experimental model.

The microvascular endothelial glycocalyx: An additional piece of the puzzle in veterinary medicine

The endothelial glycocalyx (eGlx) is a critically important structure lining the luminal surface of endothelial cells. There is increasing evidence, in human patients and animal models, for its crucial role in the maintenance of health. Moreover, its damage is associated with the pathogenesis of multiple disease states. This review provides readers with an overview of the eGlx; summarising its structure, essential functions, and evidence for its role in disease. We highlight the lack of studies regarding the eGlx in cats and dogs, particularly in naturally occurring diseases. Importantly, we discuss techniques to aid its study, which can be applied to veterinary species. Finally, we present targeted therapies aimed at preserving, and in some cases, restoring damaged eGlx.

The endothelial glycocalyx in critical illness: A pediatric perspective

The vascular endothelium is the interface between circulating blood and end organs and thus has a critical role in preserving organ function. The endothelium is lined by a glycan-rich glycocalyx that uniquely contributes to endothelial function through its regulation of leukocyte and platelet interactions with the vessel wall, vascular permeability, coagulation, and vasoreactivity. Degradation of the endothelial glycocalyx can thus promote vascular dysfunction, inflammation propagation, and organ injury. The endothelial glycocalyx and its role in vascular pathophysiology has gained increasing attention over the last decade. While studies characterizing vascular glycocalyx injury and its downstream consequences in a host of adult human diseases and in animal models has burgeoned, studies evaluating glycocalyx damage in pediatric diseases are relatively few. As children have unique physiology that differs from adults, significant knowledge gaps remain in our understanding of the causes and effects of endothelial glycocalyx disintegrity in pediatric critical illness. In this narrative literature overview, we offer a unique perspective on the role of the endothelial glycocalyx in pediatric critical illness, drawing from adult and preclinical data in addition to pediatric clinical experience to elucidate how marked derangement of the endothelial surface layer may contribute to aberrant vascular biology in children. By calling attention to this nascent field, we hope to increase research efforts to address important knowledge gaps in pediatric vascular biology that may inform the development of novel therapeutic strategies.

Biomarkers in Cardiorenal Syndrome and Potential Insights Into Novel Therapeutics

Heart and kidney failure often co-exist and confer high morbidity and mortality. The complex bi-directional nature of heart and kidney dysfunction is referred to as cardiorenal syndrome, and can be induced by acute or chronic dysfunction of either organ or secondary to systemic diseases. The five clinical subtypes of cardiorenal syndrome are categorized by the perceived primary precipitant of organ injury but lack precision. Traditional biomarkers such as serum creatinine are also limited in their ability to provide an early and accurate diagnosis of cardiorenal syndrome. Novel biomarkers have the potential to assist in the diagnosis of cardiorenal syndrome and guide treatment by evaluating the relative roles of implicated pathophysiological pathways such as hemodynamic dysfunction, neurohormonal activation, endothelial dysfunction, inflammation and oxidative stress, and fibrosis. In this review, we assess the utility of biomarkers that correlate with kidney and cardiac (dys)function, inflammation/oxidative stress, fibrosis, and cell cycle arrest, as well as emerging novel biomarkers (thrombospondin-1/CD47, glycocalyx and interleukin-1β) that may provide prediction and prognostication of cardiorenal syndrome, and guide potential development of targeted therapeutics.

Targeting repair of the vascular endothelium and glycocalyx after traumatic injury with plasma and platelet resuscitation

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Endothelial glycocalyx shedding is a key instigator of the endotheliopathy of trauma.

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Plasma and platelet transfusions preserve vascular integrity in pre-clinical models.

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However, platelets may be less effective than plasma in preserving the glycocalyx.

Severely injured patients with hemorrhagic shock can develop endothelial dysfunction, systemic inflammation, and coagulation disturbances collectively known as the endotheliopathy of trauma (EOT). Shedding of the endothelial glycocalyx occurs early after injury, contributes to breakdown of the vascular barrier, and plays a critical role in the pathogenesis of multiple organ dysfunction, leading to poor outcomes in trauma patients. In this review we discuss (i) the pathophysiology of endothelial glycocalyx and vascular barrier breakdown following hemorrhagic shock and trauma, and (ii) the role of plasma and platelet transfusion in maintaining the glycocalyx and vascular endothelial integrity.

Endothelial glycocalyx degradation during sepsis: Causes and consequences

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The endothelial glycocalyx is a ubiquitous intravascular structure essential for vascular homeostasis.

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During sepsis, the glycocalyx is degraded via the collective action of a variety of redundant sheddases, the regulation of which remains the focus of active investigation.

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Septic loss of the glycocalyx imparts both local vascular injury (leading to acute respiratory distress syndrome and acute kidney injury) as well as the systemic consequences of circulating glycosaminoglycan fragments (leading to cognitive dysfunction).

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Glycocalyx degradation during sepsis is potentially shaped by clinically-modifiable factors, suggesting opportunities for therapeutic intervention to mitigate the end-organ consequences of sepsis.

The glycocalyx is a ubiquitous structure found on endothelial cells that extends into the vascular lumen. It is enriched in proteoglycans, which are proteins attached to the glycosaminoglycans heparan sulfate, chondroitin sulfate, dermatan sulfate, keratan sulfate, and hyaluronic acid. In health and disease, the endothelial glycocalyx is a central regulator of vascular permeability, inflammation, coagulation, and circulatory tonicity. During sepsis, a life-threatening syndrome seen commonly in hospitalized patients, the endothelial glycocalyx is degraded, significantly contributing to its many clinical manifestations. In this review we discuss the intrinsically linked mechanisms responsible for septic endothelial glycocalyx destruction: glycosaminoglycan degradation and proteoglycan cleavage. We then examine the consequences of local endothelial glycocalyx loss to several organ systems and the systemic consequences of shed glycocalyx constituents. Last, we explore clinically relevant non-modifiable and modifiable factors that exacerbate or protect against endothelial glycocalyx shedding during sepsis.

Coagulopathies in Intensive Care Medicine: Balancing Act between Thrombosis and Bleeding

Patient Blood Management advocates an individualized treatment approach, tailored to each patient's needs, in order to reduce unnecessary exposure to allogeneic blood products. The optimization of hemostasis and minimization of blood loss is of high importance when it comes to critical care patients, as coagulopathies are a common phenomenon among them and may significantly impact morbidity and mortality. Treating coagulopathies is complex as thrombotic and hemorrhagic conditions may coexist and the medications at hand to modulate hemostasis can be powerful. The cornerstones of coagulation management are an appropriate patient evaluation, including the individual risk of bleeding weighed against the risk of thrombosis, a proper diagnostic work-up of the coagulopathy's etiology, treatment with targeted therapies, and transfusion of blood product components when clinically indicated in a goal-directed manner. In this article, we will outline various reasons for coagulopathy in critical care patients to highlight the aspects that need special consideration. The treatment options outlined in this article include anticoagulation, anticoagulant reversal, clotting factor concentrates, antifibrinolytic agents, desmopressin, fresh frozen plasma, and platelets. This article outlines concepts with the aim of the minimization of complications associated with coagulopathies in critically ill patients. Hereditary coagulopathies will be omitted in this review.

Use of serum hyaluronic acid as a biomarker of endothelial glycocalyx degradation in dogs with septic peritonitis

OBJECTIVE

To describe daily changes in serum concentrations of hyaluronic acid (HA), a biomarker of endothelial glycocalyx degradation, in dogs with septic peritonitis and to determine whether relationships exist among serum concentrations of HA and biomarkers of inflammation and patient fluid status.

ANIMALS

8 client-owned dogs.

PROCEDURES

Serum samples that had been collected for a previous study and stored at -80°C were used. Blood samples were collected at admission and daily thereafter during hospitalization and were analyzed for concentrations of HA and interleukins 6, 8, and 10. Patient data including acute patient physiologic and laboratory evaluation score, type and amount of fluids administered daily, and daily CBC and lactate concentration results were recorded. To determine the significant predictors of HA concentration, a general linear mixed model for repeated measures was developed.

RESULTS

All dogs survived to discharge. Concentrations of HA ranged from 18 to 1,050 ng/mL (interquartile [25th to 75th percentile] range, 49 to 119 ng/mL) throughout hospitalization. Interleukin-6 concentration was a significant predictor of HA concentration as was total administered daily fluid volume when accounting for interleukin-6 concentration. When fluid volume was analyzed independent of inflammatory status, fluid volume was not a significant predictor. Concentrations of HA did not significantly change over time but tended to increase on day 2 or 3 of hospitalization.

CONCLUSIONS AND CLINICAL RELEVANCE

Results supported the theory that inflammation is associated with endothelial glycocalyx degradation. Dogs recovering from septic peritonitis may become more susceptible to further endothelial glycocalyx damage as increasing fluid volumes are administered.

Resuscitative Strategies to Modulate the Endotheliopathy of Trauma: From Cell to Patient

Clinical data has supported the early use of plasma in high ratios of plasma to red cells to patients in hemorrhagic shock. The benefit from plasma seems to extend beyond its hemostatic effects to include protection to the post-shock dysfunctional endothelium. Resuscitation of the endothelium by plasma and one of its major constituents, fibrinogen, involves cell surface stabilization of syndecan-1, a transmembrane proteoglycan and the protein backbone of the endothelial glycocalyx. The pathogenic role of miRNA-19b to the endothelium is explored along with the PAK-1-mediated intracellular pathway that may link syndecan-1 to cytoskeletal protection. Additionally, clinical studies using fibrinogen and cyroprecipitate to aid in hemostasis of the bleeding patient are reviewed and new data to suggest a role for plasma and its byproducts to treat the dysfunctional endothelium associated with nonbleeding diseases is presented.

The Effects of Resuscitative Fluid Therapy on the Endothelial Surface Layer

The goal of resuscitative fluid therapy is to rapidly expand circulating blood volume in order to restore tissue perfusion. Although this therapy often serves to improve macrohemodynamic parameters, it can be associated with adverse effects on the microcirculation and endothelium. The endothelial surface layer (ESL) provides a protective barrier over the endothelium and is important for regulating transvascular fluid movement, vasomotor tone, coagulation, and inflammation. Shedding or thinning of the ESL can promote interstitial edema and inflammation and may cause microcirculatory dysfunction. The pathophysiologic perturbations of critical illness and rapid, large-volume fluid therapy both cause shedding or thinning of the ESL. Research suggests that restricting the volume of crystalloid, or “clear” fluid, may preserve some ESL integrity and improve outcome based on animal experimental models and preliminary clinical trials in people. This narrative review critically evaluates the evidence for the detrimental effects of resuscitative fluid therapy on the ESL and provides suggestions for future research directions in this field.

Platelet-enhanced plasma: Characterization of a novel candidate resuscitation fluid's extracellular vesicle content, clotting parameters, and thrombin generation capacity

BACKGROUND

Platelet transfusion is challenging in emergency medicine because of short platelet shelf life and stringent storage conditions. Platelet-derived extracellular vesicles (PEV) exhibit platelet-like properties. A plasma generated from expired platelet units rich in procoagulant PEV may be able to combine the benefits of plasma and platelets for resuscitation while increasing shelf life and utilizing an otherwise wasted resource.

STUDY DESIGN AND METHODS

Freeze-thaw cycling of platelet-rich plasma (PRP) followed by centrifugation to remove platelet remnants was utilized to generate platelet-enhanced plasma (PEP). An in vitro model of dilutional coagulopathy was also designed and used to test PEP. Rotational thromboelastometry and calibrated automated thrombography were used to assess clotting and extracellular vesicles (EV) procoagulant activity. Capture arrays were used to specifically measure EV subpopulations of interest (ExoView™, NanoView Biosciences). Captured vesicles were quantified and labeled with Annexin-V-FITC, CD41-PE, and CD63-AF647. Platelet alpha granule content (platelet-derived growth factor AB, soluble P-selectin, vascular endothelial growth factor A, and neutrophil activating peptide 2-chemokine (C-X-C motif) ligand 7) was measured. Commercially available platelet lysates were also characterized.

RESULTS

PEP is highly procoagulant, rich in growth factors, exhibits enhanced thrombin generation, and restores hemostasis within an in vitro model of dilutional coagulopathy. The predominant vesicle population were PEV with 7.0 × 10⁹ CD41+PS+ EV/ml compared to 4.7 × 10⁷ CD41+PS+ EV/ml in platelet-free plasma (p = .0079). Commercial lysates show impaired but rescuable clotting.

DISCUSSION

PEP is a unique candidate resuscitation fluid containing high PEV concentration with preliminary evidence, indicating a potential for upscaling the approach using platelet concentrates. Commercial lysate manufacturer workflows may be suitable for this, but further optimization and characterization of PEP is required.

Endothelial Glycocalyx as a Regulator of Fibrotic Processes

The endothelial glycocalyx, the gel layer covering the endothelium, is composed of glycosaminoglycans, proteoglycans, and adsorbed plasma proteins. This structure modulates vessels’ mechanotransduction, vascular permeability, and leukocyte adhesion. Thus, it regulates several physiological and pathological events. In the present review, we described the mechanisms that disturb glycocalyx stability such as reactive oxygen species, matrix metalloproteinases, and heparanase. We then focused our attention on the role of glycocalyx degradation in the induction of profibrotic events and on the possible pharmacological strategies to preserve this delicate structure.

Hemorrhagic Shock and Resuscitation Causes Glycocalyx Shedding and Endothelial Oxidative Stress Preferentially in the Lung and Intestinal Vasculature

INTRODUCTION

Hemorrhagic shock has recently been shown to cause shedding of a carbohydrate surface layer of endothelial cells known as the glycocalyx. This shedding of the glycocalyx is thought to be a mediator of the coagulopathy seen in trauma patients. Clinical studies have demonstrated increases in shed glycocalyx in the blood after trauma, and animal studies have measured glycocalyx disruption in blood vessels in the lung, skeletal muscle, and mesentery. However, no study has measured glycocalyx disruption across a wide range of vascular beds to quantify the primary locations of this shedding.

METHODS

In the present study, we used a rat model of hemorrhagic shock and resuscitation to more comprehensively assess glycocalyx disruption across a range of organs. Glycocalyx disruption was assessed by fluorescent-labelled wheat germ agglutinin or syndecan-1 antibody staining in flash frozen tissue.

RESULTS

We found that our model did elicit glycocalyx shedding, as assessed by an increase in plasma syndecan-1 levels. In tissue sections, we found that the greatest glycocalyx disruption occurred in vessels in the lung and intestine. Shedding to a lesser extent was observed in vessels of the brain, heart, and skeletal muscle. Liver vessel glycocalyx was unaffected, and kidney vessels, including the glomerular capillaries, displayed an increase in glycocalyx. We also measured reactive oxygen species (ROS) in the endothelial cells from these organs, and found that the greatest increase in ROS occurred in the two beds with the greatest glycocalyx shedding, the lungs and intestine. We also detected fibrin deposition in lung vessels following hemorrhage-resuscitation.

CONCLUSIONS

We conclude that the endothelium in the lungs and intestine are particularly susceptible to the oxidative stress of hemorrhage-resuscitation, as well as the resulting glycocalyx disruption. Thus these two vessel beds may be important drivers of coagulopathy in trauma patients.

Interleukin 22 mitigates endothelial glycocalyx shedding after lipopolysaccharide injury

BACKGROUND

The endothelial glycocalyx (EG) on the luminal surface of endothelial cells contributes to the permeability barrier of vessels and prevents activation of the coagulation cascade. Endothelial glycocalyx damage, which occurs in the shock state, results in endotheliopathy. Interleukin (IL)-22 is a cytokine with both proinflammatory and anti-inflammatory properties, and how IL-22 affects the EG has not been studied. We hypothesized that IL-22:Fc, a recombinant fusion protein with human IL-22 and the Fc portion of human immunoglobulin G1 (which extends the protein half-life), would not affect EG shedding in endothelium after injury.

METHODS

Human umbilical vein endothelial cells (HUVECs) were exposed to 1 μg/mL lipopolysaccharide (LPS). Lipopolysaccharide-injured cells (n = 284) were compared with HUVECs with LPS injury plus 0.375 μg/mL of IL-22:Fc treatment (n = 293) for 12 hours. These two cohorts were compared with control HUVECs (n = 286) and HUVECs exposed to IL-22:Fc alone (n = 269). Cells were fixed and stained with fluorescein isothiocyanate-labeled wheat germ agglutinin to quantify EG. Total RNA was collected, and select messenger RNAs were quantified by real time - quantitative polymerase chain reaction (RT-qPCR) using SYBR green fluorescence.

RESULTS

Exposure of HUVECs to LPS resulted in degradation of the EG compared with control (5.86 vs. 6.09 arbitrary unit [AU], p = 0.01). Interleukin-22:Fc alone also resulted in degradation of EG (5.08 vs. 6.09 AU, p = 0.01). Treatment with IL-22:Fc after LPS injury resulted in less degradation of EG compared with LPS injury alone (5.86 vs. 5.08 AU, p = 0.002). Expression of the IL-22Ra1 receptor was not different for IL-22:Fc treated compared with LPS injury only (0.69 vs. 0.86 relative expression, p = 0.10). Treatment with IL-22:Fc after LPS injury resulted in less matrix metalloproteinase 2 (0.79 vs. 1.70 relative expression, p = 0.005) and matrix metalloproteinase 14 (0.94 vs. 2.04 relative expression, p = 0.02).

CONCLUSIONS

Interleukin-22:Fc alone induces EG degradation. However, IL-22:Fc treatment after LPS injury appears to mitigate EG degradation. This protective effect appears to be mediated via reduced expression of metalloproteinases.

Liquid plasma: A solution to optimizing early and balanced plasma resuscitation in massive transfusion

BACKGROUND

Early and balanced resuscitation for traumatic hemorrhagic shock is associated with decreased mortality, making timely plasma administration imperative. However, fresh frozen plasma (FFP) thaw time can delay administration, and the shelf life of thawed FFP limits supply and may incur wastage. Liquid plasma (LP) offers an attractive alternative given immediate transfusion potential and extended shelf life. As such, we hypothesized that the use of LP in the massive transfusion protocol (MTP) would improve optimal plasma/red blood cell (RBC) ratios, initial plasma transfusion times, and clinical outcomes in the severely injured patient.

METHODS

Using Trauma Quality Improvement Program data from our level 1 trauma center, we evaluated MTP activations from 2016 to 2018. Type A LP use was instated April 2017. Before this, thawed FFP was solely used. Plasma/RBC ratios and initial plasma transfusion times were compared in MTP patients before and after LP implementation. Patient and injury characteristics were accounted for using linear regression analysis. Secondary outcomes of mortality, 28-day recovery, and complications were evaluated using Cox proportional hazards regression.

RESULTS

A total of 95 patients were included (pre-LP, 39; post-LP, 56). Time to initial plasma transfusion and plasma/RBC ratios at 4 and 24 hours were improved post-LP implementation with a coinciding reduction in RBC units transfused (p < 0.05). In a 28-day Cox proportional hazards regression LP implementation was associated with favorable recovery (hazard ratio, 3.16; 95% confidence interval, 1.60-6.24; p < 0.001) and reduction in acute kidney injury (hazard ratio, 0.092; 95% confidence interval, 0.011-0.77; p = 0.027). No post-LP patients with blood group type B or AB (n = 9) demonstrated evidence of hemolysis within 24 hours of type A LP transfusion.

CONCLUSION

Initial resuscitation with LP optimizes early plasma administration and improves adherence to transfusion ratio guidelines. Furthermore, LP offers a solution to inherent delays with FFP and is associated with improved clinical outcomes, particularly 28-day recovery and odds of acute kidney injury. Liquid plasma should be considered as an alternative to FFP in MTPs.

LEVEL OF EVIDENCE

Therapeutic/care management, level IV.

Fresh frozen plasma attenuates lung injury in a novel model of prolonged hypotensive resuscitation

BACKGROUND

Hemorrhagic shock remains a leading cause of early death among severely injured in both civilian and military settings. As future military operations will require strategies allowing prolonged field care of the injured, we sought to develop an in vivo model of prolonged hypotensive resuscitation (PHR) and to evaluate the role of plasma-based resuscitation in this model. We hypothesized that resuscitation with fresh frozen plasma (FFP) would mitigate lung injury when compared with Hextend in a rodent model of PHR.

METHODS

Mice underwent laparotomy and hemorrhagic shock (mean arterial blood pressure, 35 ± 5 mm Hg × 90 minutes) followed by PHR with either FFP or Hextend to maintain a mean arterial blood pressure of 55 mm Hg to 60 mm Hg for 6 hours. Sham animals underwent cannulation only. At the end of 6 hours, animals were euthanized, and lung tissue harvested for measurement of histopathologic injury, inflammation and permeability using hematoxylin and eosin staining, myeloperoxidase immunofluorescence staining and Evans Blue dye. Pulmonary syndecan-1 immunostaining was assessed as an indicator of endothelial cell integrity.

RESULTS

All animals in the FFP, Hextend, and sham groups survived to the end of resuscitation. Resuscitation with FFP mitigated lung histopathologic injury compared with Hextend (histologic injury score of 4.38 ± 2.07 vs. 7.5 ± 0.93, scale of 0-9, p = 0.002) and was comparable to shams (histologic injury score of 4.0 ± 1.93, scale of 0-9, p = 0.99). Fresh frozen plasma also reduced lung inflammation (0.116 ± 0.044 vs. 0.308 ± 0.054 relative fluorescence of myeloperoxidase, p = 0.002) and restored pulmonary syndecan-1 (0.514 ± 0.061 vs. 0.059 ± 0.021, relative syndecan-1 fluorescence, p < 0.001) when compared with Hextend. Consistently, FFP mitigated lung hyperpermeability compared with Hextend (7.30 ± 1.34 μg vs. 14.91 ± 5.55 μg Evans blue/100 mg lung tissue, p = 0.005).

CONCLUSION

We have presented a novel model of PHR of military relevance to the prolonged field care environment. In this model, FFP maintains its pulmonary protective effects using a PHR strategy compared with Hextend, which supports the need for further development and implementation of plasma-based resuscitation in the forward environment.

LEVEL OF EVIDENCE

Basic science.

Effect of Coagulation Factor Concentrates on Markers of Endothelial Cell Damage in Experimental Hemorrhagic Shock

BACKGROUND

Plasma-based resuscitation showed protective effects on the endothelial glycocalyx compared with crystalloid resuscitation. There is paucity of data regarding the effect of coagulation factor concentrates (CFC) on the glycocalyx in hemorrhagic shock (HS). We hypothesized that colloid-based resuscitation supplemented with CFCs offers a therapeutic value to treat endothelial damage following HS.

METHODS

Eighty-four rats were subjected to pressure-controlled (mean arterial pressure (MAP) 30-35 mm Hg) and lab-guided (targeted cutoff: lactate >2.2. mmol/L and base deficit > 5.5 mmol/L) HS. Animals were resuscitated with fresh frozen plasma (FFP), human albumin (HA) or Ringer's lactate (RL) and RL or HA supplemented with fibrinogen concentrate (FC) or prothrombin complex concentrate (PCC). Serum epinephrine and the following markers of endothelial damage were assessed at baseline and at the end-of-observation (120 min after shock was terminated): syndecan-1, heparan sulfate, and soluble vascular endothelial growth factor receptor 1 (sVEGFR 1).

RESULTS

Resuscitation with FFP had no effect on sVEGFR1 compared with crystalloid-based resuscitation (FFP: 19.3 ng/mL vs. RL: 15.9 ng/mL; RL+FC: 19.7 ng/mL; RL+PCC: 18.9 ng/mL; n.s.). At the end-of-observation, syndecan-1 was similar among all groups. Interestingly, HA+FC treated animals displayed the highest syndecan-1 concentration (12.07 ng/mL). Resuscitation with FFP restored heparan sulfate back to baseline (baseline: 36 ng/mL vs. end-of-observation: 36 ng/mL).

CONCLUSION

The current study revealed that plasma-based resuscitation normalized circulating heparan sulfate but not syndecan-1. Co-administration of CFC had no further effect on glycocalyx shedding suggesting a lack of its therapeutic potential.

LEVEL OF EVIDENCE

VExperimental in vivo study.

Role of Hypoxia in Renal Failure Caused by Nephrotoxins and Hypertonic Solutions

Hypoxia plays a role in the pathogenesis of acute kidney injury under diverse clinical settings, including nephrotoxicity. Although some nephrotoxins exert direct renal parenchymal injury, likely with consequent altered oxygenation, others primarily reduce renal parenchymal oxygenation, leading to hypoxic tubular damage. As outlined in this review, nephrotoxin-related renal hypoxia may result from an altered renal oxygen supply (cyclosporine), enhanced oxygen consumption for tubular transport (agents inducing osmotic diuresis), or their combination (nonsteroidal anti-inflammatory drugs, radiocontrast agents, and others). Most agents causing hypoxic renal injury further supress physiologic low medullary Po₂, in which a limited regional blood supply barely matches the intense regional tubular transport and oxygen consumption. The medullary tubular transport and blood supply are finely matched, securing oxygen sufficiency. Predisposition to hypoxia-mediated nephrotoxicity by medical conditions, such as chronic kidney disease or diabetes, may be explained by malfunctioning of control systems that normally maintain medullary oxygenation. However, this propensity may be diminished by hypoxia-mediated adaptive responses governed by hypoxia-inducible factors. Recent reports have suggested that inhibitors of sodium-glucose cotransporters and the administration of hypertonic saline may be added to the growing list of common therapeutic interventions that intensify medullary hypoxia, and potentially could lead to hypoxic acute kidney injury.

Role of endothelial glycocalyx in sliding friction at the catheter-blood vessel interface

Catheterization is a common medical operation to diagnose and treat cardiovascular diseases. The blood vessel lumen is coated with endothelial glycocalyx layer (EGL), which is important for the permeability and diffusion through the blood vessels wall, blood hemodynamics and mechanotransduction. However EGL’s role in catheter-blood vessel friction is not explored. We use a porcine aorta to mimic the blood vessel and a catheter loop was made to rub in reciprocating sliding mode against it to understand the role of catheter loop curvature, stiffness, normal load, sliding speed and EGL on the friction properties. Trypsin treatment was used to cause a degradation of the EGL. Decrease in catheter loop stiffness and EGL degradation were the strongest factors which dramatically increased the coefficient of friction (COF) and frictional energy dissipation at the aorta-catheter interface. Increasing sliding speed caused an increase but increase in normal load first caused a decrease and then an increase in the COF and frictional energy. These results provide the basic data for safety of operation and damage control during catheterization in patients with degraded EGL.

Immune response in fluid therapy with crystalloids of different ratios or colloid for rats in haemorrhagic shock

This study investigated the association between different ratios of balanced salt based-crystalloid (PLASMA SOLUTION-A [CJ HealthCare, Seoul, Korea]) (the ratios of crystalloid for blood loss, 1:1, 1:2 and 1:3) or balanced salt-based colloid (VOLULYTE 6% [Fresenius Kabi, Germany]) (the ratio of colloid for blood loss, 1:1) to restore blood loss and immune response in rats with haemorrhagic shock. About 50% of total estimated blood volume was removed after anaesthesia. The fluid was administered for resuscitation after exsanguination, according to the type of fluid and the ratios of exsanguinated volume and fluid volume for resuscitation. After sacrifice, expression of immune cells in blood and tissues was evaluated. Histological analyses and syndecan-1 immunohistochemistry assays were performed on tissues. Endothelial damage according to syndecan-1 and cytokine levels in blood was also assessed. Fluid resuscitation with same, two-fold, or three-fold volumes of crystalloid, or same volume of colloid, to treat haemorrhagic shock in rats resulted in a similar increase in blood pressure. The expression of neutrophils in blood decreased significantly after colloid administration, compared to before exsanguination. Syndecan-1 expression increased after exsanguination and fluid resuscitation in all groups, without any significant difference. In conclusion, same volume of balanced salt-based crystalloid for blood loss was enough to restore BP at the choice of fluid for the management of haemorrhagic shock in the rats, compared with different ratios of crystalloid or same volume of colloid, on the aspect of immune response.

The endothelial glycocalyx: Structure and function in health and critical illness

OBJECTIVE

To conduct a narrative review of the current literature in reference to the structure and function of the endothelial glycocalyx (EG) and its contribution to the pathophysiology of conditions relevant to the veterinary emergency and critical care clinician. Novel therapies for restoring or preserving the EG will also be discussed.

DATA SOURCES

Online databases (PubMed, CAB abstracts, Scopus) were searched between January 1st 2017 and May 1st 2017 for English language articles without publication date restriction. Keywords included EG, endothelial surface layer, degradation, syndecan-1, heparan sulfate, critical illness, sepsis, trauma, and therapeutics.

DATA SYNTHESIS

The EG is a complex and important structure located on the luminal surface of all blood vessels throughout the body. It plays an important role in normal vascular homeostasis including control of fluid exchange across the vascular barrier. Loss or degradation of the EG has an impact on inflammation, coagulation, and vascular permeability and tone. These changes are essential components in the pathophysiology of many conditions including sepsis and trauma. A substantial body of experimental animal and human clinical research over the last decade has demonstrated increased circulating concentrations of EG degradation products in these conditions. However, veterinary-specific research into the EG and critical illness is currently lacking. The utility of EG degradation products as diagnostic and prognostic tools continues to be investigated and new therapies to preserve or improve EG structure and function are under development.

CONCLUSIONS

The recognition of the presence of the EG has changed our understanding of transvascular fluid flux and the pathophysiology of many conditions of critical illness. The EG is an exciting target for novel therapeutics to improve morbidity and mortality in conditions such as sepsis and trauma.

Endothelial glycocalyx in acute care surgery - what anaesthesiologists need to know for clinical practice

The endothelial glycocalyx (EG) is the thin sugar-based lining on the apical surface of endothelial cells. It has been linked to the physiological functioning of the microcirculation and has been found to be damaged in critical illness and after acute care surgery. This review aims to describe the role of EG in severely injured patients undergoing surgery, discuss specific situations (e.G. major trauma, hemorrhagic shock, trauma induced coagulopathy) as well as specific interventions commonly applied in these patients (e.g. fluid therapy, transfusion) and specific drugs related to perioperative medicine with regard to their impact on EG.EG in acute care surgery is exposed to damage due to tissue trauma, inflammation, oxidative stress and inadequate fluid therapy. Even though some interventions (transfusion of plasma, human serum albumin, hydrocortisone, sevoflurane) are described as potentially EG protective there is still no specific treatment for EG protection and recovery in clinical medicine.The most important principle to be adopted in routine clinical practice at present is to acknowledge the fragile structure of the EG and avoid further damage which is potentially related to worsened clinical outcome.

Cremaster muscle perfusion, oxygenation, and heterogeneity revealed by a new automated acquisition system in a rodent model of prolonged hemorrhagic shock

Local blood flow/oxygen partial pressure (Po₂) distributions and flow-Po₂ relationships are physiologically relevant. They affect the pathophysiology and treatment of conditions like hemorrhagic shock (HS), but direct noninvasive measures of flow, Po₂, and their heterogeneity during prolonged HS are infrequently presented. To fill this void, we report the first quantitative evaluation of flow-Po₂ relationships and heterogeneities in normovolemia and during several hours of HS using noninvasive, unbiased, automated acquisition. Anesthetized rats were subjected to tracheostomy, arterial/venous catheterizations, cremaster muscle exteriorization, hemorrhage (40% total blood volume), and laparotomy. Control animals equally instrumented were not subjected to hemorrhage/laparotomy. Every 0.5 h for 4.5 h, noninvasive laser speckle contrast imaging and phosphorescence quenching were employed for nearly 7,000 flow/Po₂ measurements in muscles from eight animals, using an automated system. Precise alignment of 16 muscle areas allowed overlapping between flow and oxygenation measurements to evaluate spatial heterogeneity, and repeated measurements were used to estimate temporal heterogeneity. Systemic physiological parameters and blood chemistry were simultaneously assessed by blood samplings replaced with crystalloids. Hemodilution was associated with local hypoxia, but increased flow prevented major oxygen delivery decline. Adding laparotomy and prolonged HS resulted in hypoxia, ischemia, decreased tissue oxygen delivery, and logarithmic flow/Po₂ relationships in most regions. Flow and Po₂ spatial heterogeneities were higher than their respective temporal heterogeneities, although this did not change significantly over the studied period. This quantitative framework establishes a basis for evaluating therapies aimed at restoring muscle homeostasis, positively impacting outcomes of civilian and military trauma/HS victims.NEW & NOTEWORTHY This is the first study on flow-Po₂ relationships during normovolemia, hemodilution, and prolonged hemorrhagic shock using noninvasive methods in multiple skeletal muscle areas of monitored animals. Automated flow/Po₂ measurements revealed temporal/spatial heterogeneities, hypoxia, ischemia, and decreased tissue oxygen delivery after trauma/severe hemorrhage. Hemodilution was associated with local hypoxia, but hyperemia prevented a major decline in oxygen delivery. This framework provides a quantitative basis for testing therapeutics that positively impacts muscle homeostasis and outcomes of trauma/hemorrhagic shock victims.

Endothelial Glycocalyx Shedding Occurs during Ex Vivo Lung Perfusion: A Pilot Study

Background

Damage to the endothelium has been established as a key pathological process in lung transplantation and ex vivo lung perfusion (EVLP), a new technology that provides a platform for the assessment of injured donor lungs. Damage to the lung endothelial glycocalyx, a structure that lines the endothelium and is integral to vascular barrier function, has been associated with lung dysfunction. We hypothesised that endothelial glycocalyx shedding occurs during EVLP and aimed to establish a porcine model to investigate the mechanism underlying glycocalyx breakdown during EVLP.

Methods

Concentrations of endothelial glycocalyx breakdown products, syndecan-1, hyaluronan, heparan sulphate, and CD44, were measured using the ELISA and matrix metalloproteinase (MMP) activity by zymography in the perfusate of both human (n = 9) and porcine (n = 4) lungs undergoing EVLP. Porcine lungs underwent prolonged EVLP (up to 12 hours) with perfusion and ventilation parameters recorded hourly.

Results

During human EVLP, endothelial glycocalyx breakdown products in the perfusate increased over time. Increasing MMP-2 activity over time was positively correlated with levels of syndecan-1 (r = 0.886; p=0.03) and hyaluronan (r = 0.943; p=0.02). In the porcine EVLP model, hyaluronan was the only glycocalyx product detectable during EVLP (1 hr: 19 (13–84) vs 12 hr: 143 (109–264) ng/ml; p=0.13). Porcine hyaluronan was associated with MMP-9 activity (r = 0.83; p=0.02) and also with dynamic compliance (r = 0.57; p=0.03).

Conclusion

Endothelial glycocalyx products accumulate during both porcine and human EVLP, and this accumulation parallels an accumulation of matrix-degrading enzyme activity. Preliminary evidence in our porcine EVLP model suggests that shedding may be related to organ function, thus warranting additional study.

Graft glycocalyx degradation in human liver transplantation

OBJECTIVE

Ischaemia/reperfusion-injury degrades endothelial glycocalyx. Graft glycocalyx degradation was studied in human liver transplantation.

METHODS

To assess changes within the graft, blood was drawn from portal and hepatic veins in addition to systemic samples in 10 patients. Plasma syndecan-1, heparan sulfate and chondroitin sulfate, were measured with enzyme-linked immunosorbent assay.

RESULTS

During reperfusion, syndecan-1 levels were higher in graft caval effluent [3118 (934-6141) ng/ml, P = 0.005] than in portal venous blood [101 (75-121) ng/ml], indicating syndecan-1 release from the graft. Concomitantly, heparan sulfate levels were lower in graft caval effluent [96 (32-129) ng/ml, P = 0.037] than in portal venous blood [112 (98-128) ng/ml], indicating heparan sulfate uptake within the graft. Chondroitin sulfate levels were equal in portal and hepatic venous blood. After reperfusion arterial syndecan-1 levels increased 17-fold (P < 0.001) and heparan sulfate decreased to a third (P < 0.001) towards the end of surgery.

CONCLUSION

Syndecan-1 washout from the liver indicates extensive glycocalyx degradation within the graft during reperfusion. Surprisingly, heparan sulfate was taken up by the graft during reperfusion. Corroborating previous experimental reports, this suggests that endogenous heparan sulfate might be utilized within the graft in the repair of damaged glycocalyx.

Endothelial glycocalyx as a potential theriapeutic target in organ injuries

Objective:

The endothelial glycocalyx (eGC) is a dynamic and multicomponent layer of macromolecules found at the surface of vascular endothelium, which is largely underappreciated. It has recently been recognized that eGC is a major regulator of endothelial function and may have therapeutic value in organ injuries. This study aimed to explore the role of the eGC in various pathologic and physiologic conditions, by reviewing the basic research findings pertaining to the detection of the eGC and its clinical significance. We also explored different pharmacologic agents used to protect and rebuild the eGC.

Data sources:

An in-depth search was performed in the PubMed database, focusing on research published after 2003 with keywords including eGC, permeability, glycocalyx and injuries, and glycocalyx protection.

Study selection:

Several authoritative reviews and original studies were identified and reviewed to summarize the characteristics of the eGC under physiologic and pathologic conditions as well as the detection and protection of the eGC.

Results:

The eGC degradation is closely associated with pathophysiologic changes such as vascular permeability, edema formation, mechanotransduction, and clotting cascade, together with neutrophil and platelet adhesion in diverse injury and disease states including inflammation (sepsis and trauma), ischemia-reperfusion injury, shock, hypervolemia, hypertension, hyperglycemia, and high Na⁺ as well as diabetes and atherosclerosis. Therapeutic strategies for protecting and rebuilding the eGC should be explored through experimental test and clinical verifications.

Conclusions:

Disturbance of the eGC usually occurs at early stages of various clinical pathophysiologies which can be partly prevented and reversed by protecting and restoring the eGC. The eGC seems to be a promising diagnostic biomarker and therapeutic target in clinical settings.

Experimental Models of Endotheliopathy: Impact of Shock Severity

BACKGROUND

Hemorrhagic shock (HS) followed by resuscitation is often associated with sympathoadrenal activation (SAA) and endothelial damage (ED).

OBJECTIVE

We aimed to evaluate the impact of HS alone on the magnitude of SAA and consecutive ED, and to characterize potential targets for a standardized and reproducible model of HS-induced endotheliopathy in rats.

METHODS

Rats were subjected either to a volume-controlled HS (40% of total blood volume: v-HS group) or to a laboratory-guided HS (l-HS) targeting base deficit (BD) more than 5.5 mmol/L and/or lactate more than 2.2 mmol/L using a pressure-controlled volume loss.

RESULTS

At the end of shock, mean arterial pressure was significantly higher in the v-HS than the l-HS group (36 ± 5.6 vs. 30 ± 3.0 mmHg; P < 0.01). Base deficit and lactate were higher in l-HS than the v-HS group (BD: 9.5 ± 2.5 vs. 3.0 ± 1.0 mmol/L; P < 0.001; lactate: 4.1 ± 1.3 vs. 1.6 ± 0.6 mmol/L; P < 0.001). sVEGFR-1 and syndecan-1 were approximately 50% higher in the l-HS than the v-HS group (% changes vs. baseline: 160 ± 10 vs. 116 ± 36; P < 0.01; 170 ± 37 vs. 113 ± 27; P < 0.001). Adrenaline was 2-fold higher in l-HS than the v-HS group (1964 ± 961% vs. 855 ± 451%; P < 0.02, respectively). Moreover, linear regression analysis revealed an independent association of shock severity BD with syndecan-1 (rho = 0.55, P = 0.0005), sVEGFR1 (rho = 0.25, P < 0.05), and adrenaline (rho = 0.31, P = 0.021).

CONCLUSIONS

Our findings indicate that ED has already occurred during HS without reperfusion; intensity is strongly related to the severity of HS and consecutive SAA; and severity may appropriately be targeted and standardized in a HS model controlled by biological endpoints such as BD and/or lactate.