TNF-α induced shedding of the endothelial glycocalyx is prevented by hydrocortisone and antithrombin

The oral microbiota: new insight into intracranial aneurysms

BACKGROUND

Intracranial aneurysms (IAs) are a significant clinical concern, with detection rates increasing due to advances in imaging technologies. However, precise mechanisms underlying their pathophysiology remain incompletely understood. Recent evidence suggests a pivotal role of oral microbiota dysbiosis, particularly periodontal pathogens, in systemic inflammation that may contribute to IA development and rupture.

OBJECTIVE

This review aims to critically evaluate the association between oral microbiota dysbiosis and the pathogenesis of IAs, with a focus on the molecular and immunological mechanisms by which oral pathogens influence vascular pathology.

METHODS

We conducted a comprehensive analysis of the literature regarding the impact of oral microbial dysbiosis on IA pathophysiology, emphasizing the role of specific pathogenic species, such as Porphyromonas gingivalis. The review explores how these pathogens may mediate chronic inflammation through hematogenous spread, gut microbiome alterations, and neuroinflammatory processes, leading to vascular remodeling and cerebrovascular instability.

RESULTS

The findings suggest that oral microbial dysbiosis, particularly the presence of pathogenic bacteria, is implicated in the systemic inflammatory response that exacerbates the structural integrity of the cerebrovascular wall. Chronic inflammatory states induced by oral pathogens contribute to extracellular matrix degradation, impaired vascular remodeling, and an increased susceptibility to IA rupture.

CONCLUSIONS

The findings highlight the importance of maintaining oral microbiota homeostasis as a potential therapeutic target for preventing IAs. Interventions aimed at restoring oral microbial balance may represent a novel strategy for reducing the burden of IA formation and rupture, highlighting the need for an integrated approach to oral health and IAs prevention.

Acute neuroendocrine challenge elicits enhanced cortisol response and parallel transcriptomic changes in patients with migraine

Introduction

Migraine is a neurological disorder with recurrent attacks characterized by headaches and sensitivity to stimuli. Stress is a significant trigger for attacks; however, molecular mechanisms of the connection are poorly understood.

Objectives

To better characterize such mechanisms, we performed a placebo-controlled, double-blind crossover study with 51 participants (21 patients with migraine without aura and 30 healthy controls).

Methods

Participants received a low-dose citalopram- or placebo challenge on 2 separate days. Prechallenge and postchallenge assessment of cortisol concentrations and transcriptomic changes using RNA-seq was performed from whole blood samples. Analysis of an accidental attack following the citalopram challenge was also conducted.

Results

Neuroendocrine challenge elicited elevated cortisol concentrations at 30 (P-value = 0.1355) and 70 minutes (P-value = 0.07292) postchallenge in patients with migraine compared with controls. Gene expression analysis showed 10 differentially expressed genes (2 down- and 8 upregulated, P-value ≤ 0.005) and 10 dysregulated gene sets (P-value ≤ 0.005). Among them, dysregulated IKBKGP1 and NKRF genes and upregulated protein synthesis and translation, carbohydrate metabolism, and, attack-related, glycosylation can be highlighted.

Conclusion

Patients with migraine without aura showed an enhanced cortisol response to a neuroendocrine challenge. This was accompanied by a probable suppression of NFκB activity through dysregulation of NKRF and an altered immune function. Upregulated carbohydrate metabolism may reflect the elevated cortisol concentrations' stimulating effects on endothelial glycocalyx, playing a role in NO-induced vasodilation, a trigger for migraine attacks. The results suggest the elevated cortisol response may trigger migraine attacks through altered glycocalyx and immune functions.

Comparison of clinical efficacy and secondary infections between conventional-dose and high-dose glucocorticoid in hemorrhagic fever with renal syndrome: a dual-center retrospective cohort study

BACKGROUND

Glucocorticoids (GC) are commonly administered during the febrile and hypotensive phases of hemorrhagic fever with renal syndrome (HFRS) to alleviate inflammation and capillary leakage. However, clinical dosing regimens show marked variability. This study aims to evaluate the clinical necessity of high-dose GC therapy during the acute phase of HFRS.

METHODS

A retrospective study involving 807 HFRS patients admitted to two centers was conducted. Propensity score matching and multivariate logistic regression models were used to compare the effects of conventional-dose and high-dose GC on HFRS treatment outcomes and the risk of secondary infections.

RESULTS

There were no significant differences in hospital stay, acute-phase fluid requirement, renal replacement rates, mechanical ventilation needs, severe hemorrhagic complications, or mortality between HFRS patients receiving conventional or high-dose GC. Among patients with a shock phase, the secondary infections rate was significantly higher with high-dose GC compared to conventional-dose (43.48% vs. 23.91%, p = 0.005). High-dose GC emerged as an independent risk factor for secondary infections (OR 2.88, 95%CI 1.41-5.88), while prophylactic antibiotics served as an independent protective factor (OR 0.29, 95%CI 0.13-0.65). In patients without a shock phase, no significant difference was observed in the effect of the two GC doses on secondary infections. However, GC therapy ≥ 4 days was an independent risk factor (OR 2.54, 95%CI 1.21-5.37).

CONCLUSIONS

High-dose GC show no superiority over conventional-dose GC on hospital stay, acute-phase fluid requirement, renal replacement rates, mechanical ventilation needs, severe hemorrhagic complications, or mortality. High-dose GC may increase secondary infections in HFRS patients with a shock phase. GC therapy ≥ 4 days may also increase secondary infections in patients without a shock phase.

The glycocalyx: a key target for treatment of severe acute pancreatitis-associated multiple organ dysfunction syndrome

The endothelial glycocalyx is a dynamic brush-like layer composed of proteoglycans and glycosaminoglycans, including heparan sulfate (HS) and hyaluronic acid (HA), and is an important regulator of vascular homeostasis. Its structure (thickness ranges from 20 to 6450 nm in different species) not only provides a charge-selective barrier but also serves to anchor mechanosensors such as the glypican-1 (GPC-1)/caveolin-1 (CAV-1) complex and buffers shear stress. In severe acute pancreatitis (SAP), inflammatory factors promote the expression of matrix metalloproteinases (MMPs) and heparinases, which degrade syndecan-1 (SDC-1) and HS, while oxidative stress disrupts HA-CD44 binding, leading to increased capillary leakage and neutrophil adhesion. This degradation process occurs before the onset of multiple organ dysfunction syndrome (MODS), highlighting the potential of the glycocalyx as an early biomarker. More importantly, the regeneration of glycocalyx through endothelial cell synthesis of glycosaminoglycans (GAGs) and shear stress-driven SDC recycling provides therapeutic prospects. This review redefines the pathophysiology of severe acute pancreatitis-associated multiple organ dysfunction (SAP-MODS) by exploring the glycocalyx's central mechanistic role and proposes stabilizing glycocalyx structure as a potential strategy to prevent microcirculatory failure.

Crystalloids versus Colloids: Same Controversy, New Information

Intravenous fluid therapy is a regular component of care for cats and dogs with goals of restoring tissue perfusion, preventing organ dysfunction, and maintaining homeostasis. Veterinarians have a plethora of fluid choices, including hypertonic, hypotonic, and isotonic crystalloids, as well as synthetic and natural colloids. Studies published in both the human and veterinary medical literature have documented adverse events associated with synthetic and natural colloids. Reports of increased incidences of acute kidney injury, need for renal replacement therapy, and mortality in a variety of patient populations have called into question the use of synthetic colloids in humans and companion animals.

Co-therapy with S1P and heparan sulfate derivatives to restore endothelial glycocalyx and combat pro-atherosclerotic endothelial dysfunction

AIMS

Endothelial cell (EC) glycocalyx (GCX) shedding from disturbed blood flow and chemical factors leads to low-density lipoprotein infiltration, reduced nitric oxide synthesis, vascular dysfunction and atherosclerosis. This study evaluates a therapy combining sphingosine-1-phosphate (S1P) and heparin (heparan sulfate derivative). We hypothesized that heparin/S1P co-treatment repairs mechanically damaged EC GCX in disturbed flow (DF) regions and restores anti-atherosclerotic mechanotransduction to treat cardiovascular disease.

MATERIALS AND METHODS

We used a parallel-plate flow chamber to simulate flow conditions in vitro and a partial carotid ligation mouse model to mimic DF in vivo. Heparin and albumin-bound S1P were administered to assess their reparative effects on the endothelial GCX. Fluorescent staining, confocal microscopy, and ultrasound evaluated endothelial cell function and endothelial-dependent vascular function. Barrier functionality was assessed via macrophage uptake. Heparin/S1P mechanism-of-action insights were gained through fluid dynamics simulations and staining of GCX synthesis enzyme and S1P receptor. Statistical analyses validated the results.

KEY FINDINGS

The in vitro data showed that heparin/S1P therapy improves DF-conditioned ECs by restoring GCX and elevating vasodilator eNOS (endothelial-type nitric oxide synthase) expression. In vivo studies confirmed GCX degradation, vessel inflammation, hyperpermeability, and wall thickening in the mouse model's partially ligated left carotid artery. Heparin/S1P treatment restored GCX thickness and coverage, reduced inflammation and hyperpermeability, and inhibited vessel wall thickening.

SIGNIFICANCE

This work introduces a new approach to regenerating the EC GCX and restoring its function in ECs under DF conditions, offering a groundbreaking solution for preventing cardiovascular diseases like atherosclerosis.

Experimental and clinical perspectives on glycocalyx integrity and its relation to acute respiratory distress syndrome

The development of microcirculation imaging devices has significantly advanced our comprehension of the capillary environment's dynamics. Early research suggested that erythrocytes did not contact the vessel's inner surface due to the Fåhraeus effect, implying the presence of a covering on the endothelial cell surface. Subsequent electron microscopy studies revealed this layer to be a complex part of the vessel wall, now known as the endothelial glycocalyx (EG). The EG is a network of proteoglycans and glycoproteins bound to the endothelial membrane, incorporating soluble molecules from the endothelium and plasma. Over time, studies have elucidated the structure, function, and therapeutic targets of the glycocalyx, underscoring its pivotal role in vascular biology. The presence of cellular extensions of lung tissue cells in both vascular and nonvascular areas demonstrates the pivotal role of the glycocalyx in pulmonary vascular leak, surfactant dysfunction, impaired lung compliance and gas exchange abnormalities, which are hallmarks of acute respiratory distress syndrome (ARDS). It is of the utmost importance to elucidate the mechanisms underlying alveolocapillary glycocalyx degradation to develop efficacious treatments for ARDS, which has a mortality rate of 35 %. An understanding of the glycocalyx's role in vascular integrity provides a foundation for exploring new therapeutic avenues to mitigate lung injury and improve clinical outcomes in ARDS patients.

Sepsis-associated endothelial glycocalyx damage: a review of animal models, clinical evidence, and molecular mechanisms

In the mammalian cardiovascular system, endothelial glycocalyx is a gel-like layer that covers the luminal surface of endothelial cells (ECs) and plays crucial roles in vascular homeostasis, permeability and leukocyte adhesion. Degradation of this structure occurs early in sepsis and becomes accordingly dysfunctional. In severe cases, it is not self-regulated by the organism. However, the relationship between the glycocalyx and the occurrence and development of sepsis remains poorly understood. One possibility is that thinned glycocalyx promotes leukocyte recognition and adhesion, thereby facilitating the elimination of pathogens from infected areas. This may represent a protective mechanism developed by the organism during through evolutionary processes. However, if the damage persists and disrupts the dynamic balance of the microcirculation, interstitial edema or organ failure can occur. Thus, we asked the questions, what is the precise composition and structure of the glycocalyx? How is it degraded? What animal models are available to study the relationship between the glycocalyx and sepsis? What glycocalyx biomarkers are found in the blood of patients with sepsis? To determine whether sepsis can be treated by interfering with the glycocalyx, this study provides a systematic summary and discussion of the latest progress in addressing these questions.

Ulinastatin treatment mitigates glycocalyx degradation and associated with lower postoperative delirium risk in patients undergoing cardiac surgery: a multicentre observational study

BACKGROUND

Ulinastatin (UTI), recognized for its anti-inflammatory properties, holds promise for patients undergoing cardiac surgery. This study aimed to investigate the relationship between intraoperative UTI administration and the incidence of delirium following cardiac surgery.

METHODS

A retrospective analysis was performed on a retrospective cohort of 6,522 adult cardiac surgery patients to evaluate the relationship between UTI treatment and the incident of postoperative delirium (POD) in patients ongoing cardiac surgery. This was followed by a prospective observational cohort study of 241 patients and an in vitro study to explore the findings and the potential role of UTI in preventing cardiac ischemia-reperfusion induced glycocalyx degradation.

RESULTS

Both univariate and multivariate logistic regression analyses in retrospective cohort indicated that intraoperative administration of UTI was associated with a significant lower risk of POD among cardiac surgery patients, a finding confirmed through employing propensity score matching. The subsequent prospective observational cohort further supported these findings (adjusted Odds Ratio = 0.392, 95% CI: 0.157-0.977, P = 0.044). Furthermore, UTI mitigated glycocalyx degradation, as demonstrated by in vitro study.

CONCLUSIONS

UTI administration may mitigate glycocalyx degradation, potentially lowering the risk of POD in cardiac surgery patients, offering valuable insights for future interventions to prevent POD and enhance patient outcomes. Trial registration number ClinicalTrials.gov (No. NCT06268249). Retrospectively registered 4 February 2024.

Factors influencing glycocalyx degradation: a narrative review

The glycocalyx is a layer of villus-like structure covering the luminal surface of vascular endothelial cells. Damage to the glycocalyx has been proven linked to the development of many diseases. However, the factors that promote damage to the glycocalyx are not fully elaborated. This review summarizes factors leading to the reduction of the glycocalyx in detail, including inflammatory factors, ischemia-reperfusion, oxidative stress, lipids, glucose, high sodium, female sex hormones and others. Additionally, the mechanisms underlying its degradation are discussed. To better prevent and treat related diseases induced by glycocalyx degradation, it is a meaningful measure to avoid these factors.

Co-Therapy with S1P and Heparan Sulfate Derivatives to Restore Endothelial Glycocalyx and Combat Pro-Atherosclerotic Endothelial Dysfunction

Endothelial cell (EC) glycocalyx (GCX) shedding due to disturbed blood flow and chemical factors leads to low-density lipoprotein infiltration and reduced nitric oxide synthesis, causing vascular dysfunction and atherosclerosis. This study evaluates a novel therapy combining sphingosine-1-phosphate (S1P) and heparin (heparan sulfate derivative). We hypothesized that heparin/S1P would repair mechanically damaged EC GCX in disturbed flow (DF) regions and restore anti-atherosclerotic mechanotransduction function, addressing cardiovascular disease. We used a parallel-plate flow chamber to simulate flow conditions in vitro and a partial carotid ligation mouse model to mimic DF in vivo. Heparin and albumin-bound S1P were administered to assess their reparative effects on the endothelial GCX. Immunocytochemistry, fluorescent staining, confocal microscopy, cellular alignment studies, and ultrasound were performed to evaluate EC function and endothelial-dependent vascular function. Barrier functionality was assessed via macrophage uptake. Heparin/S1P mechanism-of-action insights were gained through fluid dynamics simulations and staining of GCX synthesis enzyme as well as S1P receptor. Statistical analyses validated results. In vitro data showed that heparin/S1P therapy improves the function of DF-conditioned ECs by restoring EC GCX and promoting EC alignment and elevated vasodilator eNOS (endothelial-type nitric oxide synthase) expression. The in vivo studies confirmed GCX degradation, increased vessel inflammation and hyperpermeability, and vessel wall thickening in the partially ligated left carotid artery. Heparin/S1P treatment restored GCX in the left carotid artery, enhancing GCX thickness and coverage of the blood vessel wall. This work advances a new approach to regenerating the EC GCX and restoring its function in ECs under DF conditions.

Personalized Vascularized Models of Breast Cancer Desmoplasia Reveal Biomechanical Determinants of Drug Delivery to the Tumor

Desmoplasia in breast cancer leads to heterogeneity in physical properties of the tissue, resulting in disparities in drug delivery and treatment efficacy among patients, thus contributing to high disease mortality. Personalized in vitro breast cancer models hold great promise for high-throughput testing of therapeutic strategies to normalize the aberrant microenvironment in a patient-specific manner. Here, tumoroids assembled from breast cancer cell lines (MCF7, SKBR3, and MDA-MB-468) and patient-derived breast tumor cells (TCs) cultured in microphysiological systems including perfusable microvasculature reproduce key aspects of stromal and vascular dysfunction causing impaired drug delivery. Models containing SKBR3 and MDA-MB-468 tumoroids show higher stromal hyaluronic acid (HA) deposition, vascular permeability, interstitial fluid pressure (IFP), and degradation of vascular HA relative to models containing MCF7 tumoroids or models without tumoroids. Interleukin 8 (IL8) secretion is found responsible for vascular dysfunction and loss of vascular HA. Interventions targeting IL8 or stromal HA normalize vascular permeability, perfusion, and IFP, and ultimately enhance drug delivery and TC death in response to perfusion with trastuzumab and cetuximab. Similar responses are observed in patient-derived models. These microphysiological systems can thus be personalized by using patient-derived cells and can be applied to discover new molecular therapies for the normalization of the tumor microenvironment.

The Glycocalyx: The Importance of Sugar Coating the Blood-Brain Barrier

The endothelial glycocalyx (GCX), located on the luminal surface of vascular endothelial cells, is composed of glycoproteins, proteoglycans, and glycosaminoglycans. It plays a pivotal role in maintaining blood-brain barrier (BBB) integrity and vascular health within the central nervous system (CNS), influencing critical processes such as blood flow regulation, inflammation modulation, and vascular permeability. While the GCX is ubiquitously expressed on the surface of every cell in the body, the GCX at the BBB is highly specialized, with a distinct composition of glycans, physical structure, and surface charge when compared to GCX elsewhere in the body. There is evidence that the GCX at the BBB is disrupted and partially shed in many diseases that impact the CNS. Despite this, the GCX has yet to be a major focus of therapeutic targeting for CNS diseases. This review examines diverse model systems used in cerebrovascular GCX-related research, emphasizing the importance of selecting appropriate models to ensure clinical relevance and translational potential. This review aims to highlight the importance of the GCX in disease and how targeting the GCX at the BBB specifically may be an effective approach for brain specific targeting for therapeutics.

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.

The potential involvement of glycocalyx disruption in abdominal aortic aneurysm pathogenesis

BACKGROUND

Abdominal aortic aneurysm is a weakening and expansion of the abdominal aorta. Currently, there is no drug treatment to limit abdominal aortic aneurysm growth. The glycocalyx is the outermost layer of the cell surface, mainly composed of glycosaminoglycans and proteoglycans.

OBJECTIVE

The aim of this review was to identify a potential relationship between glycocalyx disruption and abdominal aortic aneurysm pathogenesis.

METHODS

A narrative review of relevant published research was conducted.

RESULTS

Glycocalyx disruption has been reported to enhance vascular permeability, impair immune responses, dysregulate endothelial function, promote extracellular matrix remodeling and modulate mechanotransduction. All these effects are implicated in abdominal aortic aneurysm pathogenesis. Glycocalyx disruption promotes inflammation through exposure of adhesion molecules and release of proinflammatory mediators. Glycocalyx disruption affects how the endothelium responds to shear stress by reducing nitric oxide availabilty and adversely affecting the storage and release of several antioxidants, growth factors, and antithromotic proteins. These changes exacerbate oxidative stress, stimulate vascular smooth muscle cell dysfunction, and promote thrombosis, all effects implicated in abdominal aortic aneurysm pathogenesis. Deficiency of key component of the glycocalyx, such as syndecan-4, were reported to promote aneurysm formation and rupture in the angiotensin-II and calcium chloride induced mouse models of abdominal aortic aneurysm.

CONCLUSION

This review provides a summary of past research which suggests that glycocalyx disruption may play a role in abdominal aortic aneurysm pathogenesis. Further research is needed to establish a causal link between glycocalyx disruption and abdominal aortic aneurysm development.

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.

Scanning Probe Microscopy Techniques for Studying the Cell Glycocalyx

The glycocalyx is a brush-like layer that covers the surfaces of the membranes of most cell types. It consists of a mixture of carbohydrates, mainly glycoproteins and proteoglycans. Due to its structure and sensitivity to environmental conditions, it represents a complicated object to investigate. Here, we review studies of the glycocalyx conducted using scanning probe microscopy approaches. This includes imaging techniques as well as the measurement of nanomechanical properties. The nanomechanics of the glycocalyx is particularly important since it is widely present on the surfaces of mechanosensitive cells such as endothelial cells. An overview of problems with the interpretation of indirect data via the use of analytical models is presented. Special insight is given into changes in glycocalyx properties during pathological processes. The biological background and alternative research methods are briefly covered.

Acute pyelonephritis in pregnancy and plasma syndecan-1: evidence of glycocalyx involvement

BACKGROUND

Acute pyelonephritis, a risk factor for maternal sepsis, adult respiratory distress syndrome, and preterm labor, is a frequent cause of hospitalization. This condition is characterized by excessive intravascular inflammation and endothelial cell activation and dysfunction. Syndecan-1, a major component of the glycocalyx, is a gel-like layer that covers the luminal surface of healthy endothelial cells, preserving and mediating many endothelial functions. During pregnancy, there is an additional potential source of syndecan-1, the "syncytiotrophoblast glycocalyx," which lines the intervillous space. Insults that damage the glycocalyx lead to a shedding of syndecan-1 into the circulation. Hence, syndecan-1 has been proposed as a marker of endothelial injury in conditions such as sepsis, trauma, cardiovascular disease, and diabetes mellitus.

OBJECTIVE

The objective of this study was to determine whether the plasma syndecan-1 concentration changes in women with acute pyelonephritis in the presence or absence of bacteremia.

STUDY DESIGN

This cross-sectional study included three groups: (1) non-pregnant women (n = 25); (2) women with an uncomplicated pregnancy from whom samples were collected preterm (n = 61) or at term (n = 69); and (3) pregnant women diagnosed with acute pyelonephritis from whom samples were collected at the time of diagnosis during the second and third trimesters (n = 33). The diagnosis of acute pyelonephritis was based on clinical findings and a positive urine culture for bacteria. Blood culture results were available in 85% (28/33) of women with acute pyelonephritis. Plasma concentrations of syndecan-1 were determined by a validated immunoassay.

RESULTS

(1) Women with an uncomplicated pregnancy had a higher plasma concentration of syndecan-1 than non-pregnant women. The geometric mean (95% confidence interval [CI]) of syndecan-1 concentration was 51.0 (12.1-216.1) ng/mL in non-pregnant controls; 1280 (365-4487) ng/mL in normal preterm gestations; and 1786 (546-5834) ng/mL in normal term gestations (adjusted p < .005 for all three between group comparisons); (2) plasma syndecan-1 concentrations increased with gestational age among women with a normal pregnancy (p < .001, R2 = 0.27); (3) syndecan-1 multiple of the mean (MoM) values in pregnant patients with acute pyelonephritis were higher than those in normal pregnant women based on second- and third-trimester samples (p = .048, 1.26-fold change). The increase was driven primarily by cases with a positive blood culture (p = .009, 1.74-fold change); (4) when data from third-trimester samples were compared, overall differences in syndecan-1 MoM values between cases and controls were slightly larger (p = .03, 1.36- fold change), which were especially contributed to by cases with a positive blood culture (p = .023, fold change 1.79-fold change).

CONCLUSIONS

Plasma syndecan-1 concentration is higher in pregnant women and increases as a function of gestational age. Patients with acute pyelonephritis have a higher plasma concentration of syndecan-1, and this is particularly the case in the presence of bacteremia.

Endothelial Glycocalyx of Peritubular Capillaries in Experimental Diabetic Nephropathy: A Target of ACE Inhibitor-Induced Kidney Microvascular Protection

Peritubular capillary rarefaction is a recurrent aspect of progressive nephropathies. We previously found that peritubular capillary density was reduced in BTBR ob/ob mice with type 2 diabetic nephropathy. In this model, we searched for abnormalities in the ultrastructure of peritubular capillaries, with a specific focus on the endothelial glycocalyx, and evaluated the impact of treatment with an angiotensin-converting enzyme inhibitor (ACEi). Mice were intracardially perfused with lanthanum to visualise the glycocalyx. Transmission electron microscopy analysis revealed endothelial cell abnormalities and basement membrane thickening in the peritubular capillaries of BTBR ob/ob mice compared to wild-type mice. Remodelling and focal loss of glycocalyx was observed in lanthanum-stained diabetic kidneys, associated with a reduction in glycocalyx components, including sialic acids, as detected through specific lectins. ACEi treatment preserved the endothelial glycocalyx and attenuated the ultrastructural abnormalities of peritubular capillaries. In diabetic mice, peritubular capillary damage was associated with an enhanced tubular expression of heparanase, which degrades heparan sulfate residues of the glycocalyx. Heparanase was also detected in renal interstitial macrophages that expressed tumor necrosis factor-α. All these abnormalities were mitigated by ACEi. Our findings suggest that, in experimental diabetic nephropathy, preserving the endothelial glycocalyx is important in order to protect peritubular capillaries from damage and loss.

Endothelial cell activation and glycocalyx shedding - potential as biomarkers in patients with lupus nephritis

Lupus nephritis (LN) is a common and severe manifestation of systemic lupus erythematosus and an important cause of acute and chronic kidney injury. Early diagnosis of LN and preventing relapses are key to preserving renal reserve. However, due to the complexity and heterogeneity of the disease, clinical management remains challenging. Kidney biopsy remains the gold standard for confirming the diagnosis of LN and subsequent assessment of kidney histopathology, but it is invasive and cannot be repeated frequently. Current clinical indicators of kidney function such as proteinuria and serum creatinine level are non-specific and do not accurately reflect histopathological changes, while anti-dsDNA antibody and C3 levels reflect immunological status but not kidney injury. Identification of novel and specific biomarkers for LN is prerequisite to improve management. Renal function deterioration is associated with changes in the endothelial glycocalyx, a delicate gel-like layer located at the interface between the endothelium and bloodstream. Inflammation induces endothelial cell activation and shedding of glycocalyx constituents into the circulation. This review discusses the potential role of soluble glycocalyx components as biomarkers of active LN, especially in patients in whom conventional serological and biochemical markers do not appear helpful.

The genesis of cardiovascular risk in inflammatory arthritis: insights into glycocalyx shedding, endothelial dysfunction, and atherosclerosis initiation

This narrative review provides a comprehensive examination of the complex interplay between inflammatory arthritis (IA) and cardiovascular pathology. It particularly illuminates the roles of atherosclerosis initiation, endothelial dysfunction, and glycocalyx shedding. IA not only provokes tissue-specific inflammatory responses, but also engenders a considerable degree of non-specific systemic inflammation. This review underscores the accelerating influence of the chronic inflammatory milieu of IA on cardiovascular disease (CVD) progression. A focal point of our exploration is the critical function of the endothelial glycocalyx (EG) in this acceleration process, which possibly characterizes the earliest phases of atherosclerosis. We delve into the influence of inflammatory mediators on microtubule dynamics, EG modulation, immune cell migration and activation, and lipid dysregulation. We also illuminate the impact of microparticles and microRNA on endothelial function. Further, we elucidate the role of systemic inflammation and sheddases in EG degradation, the repercussions of complement activation, and the essential role of syndecans in preserving EG integrity. Our review provides insight into the complex and dynamic interface between systemic circulation and the endothelium.

Endothelial Glycocalyx Injury in SARS-CoV-2 Infection: Molecular Mechanisms and Potential Targeted Therapy

This review aims at summarizing state-of-the-art knowledge on glycocalyx and SARS-CoV-2. The endothelial glycocalyx is a dynamic grid overlying the surface of the endothelial cell (EC) lumen and consists of membrane-bound proteoglycans and glycoproteins. The role of glycocalyx has been determined in the regulation of EC permeability, adhesion, and coagulation. SARS-CoV-2 is an enveloped, single-stranded RNA virus belonging to β-coronavirus that causes the outbreak and the pandemic of COVID-19. Through the respiratory tract, SARS-CoV-2 enters blood circulation and interacts with ECs possessing angiotensin-converting enzyme 2 (ACE2). Intact glycolyx prevents SARS-CoV-2 invasion of ECs. When the glycocalyx is incomplete, virus spike protein of SARS-CoV-2 binds with ACE2 and enters ECs for replication. In addition, cytokine storm targets glycocalyx, leading to subsequent coagulation disorder. Therefore, it is intriguing to develop a novel treatment for SARS-CoV-2 infection through the maintenance of the integrity of glycocalyx. This review aims to summarize state-of-the-art knowledge of glycocalyx and its potential function in SARS-CoV-2 infection.

Coronary No-Reflow after Primary Percutaneous Coronary Intervention-Current Knowledge on Pathophysiology, Diagnosis, Clinical Impact and Therapy

Coronary no-reflow (CNR) is a frequent phenomenon that develops in patients with ST-segment elevation myocardial infarction (STEMI) following reperfusion therapy. CNR is highly dynamic, develops gradually (over hours) and persists for days to weeks after reperfusion. Microvascular obstruction (MVO) developing as a consequence of myocardial ischemia, distal embolization and reperfusion-related injury is the main pathophysiological mechanism of CNR. The frequency of CNR or MVO after primary PCI differs widely depending on the sensitivity of the tools used for diagnosis and timing of examination. Coronary angiography is readily available and most convenient to diagnose CNR but it is highly conservative and underestimates the true frequency of CNR. Cardiac magnetic resonance (CMR) imaging is the most sensitive method to diagnose MVO and CNR that provides information on the presence, localization and extent of MVO. CMR imaging detects intramyocardial hemorrhage and accurately estimates the infarct size. MVO and CNR markedly negate the benefits of reperfusion therapy and contribute to poor clinical outcomes including adverse remodeling of left ventricle, worsening or new congestive heart failure and reduced survival. Despite extensive research and the use of therapies that target almost all known pathophysiological mechanisms of CNR, no therapy has been found that prevents or reverses CNR and provides consistent clinical benefit in patients with STEMI undergoing reperfusion. Currently, the prevention or alleviation of MVO and CNR remain unmet goals in the therapy of STEMI that continue to be under intense research.

Endothelial Glycocalyx Preservation-Impact of Nutrition and Lifestyle

The endothelial glycocalyx (eGC) is a dynamic hair-like layer expressed on the apical surface of endothelial cells throughout the vascular system. This layer serves as an endothelial cell gatekeeper by controlling the permeability and adhesion properties of endothelial cells, as well as by controlling vascular resistance through the mediation of vasodilation. Pathogenic destruction of the eGC could be linked to impaired vascular function, as well as several acute and chronic cardiovascular conditions. Defining the precise functions and mechanisms of the eGC is perhaps the limiting factor of the missing link in finding novel treatments for lifestyle-related diseases such as atherosclerosis, type 2 diabetes, hypertension, and metabolic syndrome. However, the relationship between diet, lifestyle, and the preservation of the eGC is an unexplored territory. This article provides an overview of the eGC's importance for health and disease and describes perspectives of nutritional therapy for the prevention of the eGC's pathogenic destruction. It is concluded that vitamin D and omega-3 fatty acid supplementation, as well as healthy dietary patterns such as the Mediterranean diet and the time management of eating, might show promise for preserving eGC health and, thus, the health of the cardiovascular system.

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.

Inflammatory stimuli induce shedding of heparan sulfate from arterial but not venous porcine endothelial cells leading to differential proinflammatory and procoagulant responses

Endothelial dysfunction is an early event of vascular injury defined by a proinflammatory and procoagulant endothelial cell (EC) phenotype. Although endothelial glycocalyx disruption is associated with vascular damage, how various inflammatory stimuli affect the glycocalyx and whether arterial and venous cells respond differently is unknown. Using a 3D round-channel microfluidic system we investigated the endothelial glycocalyx, particularly heparan sulfate (HS), on porcine arterial and venous ECs. Heparan sulfate (HS)/glycocalyx expression was observed already under static conditions on venous ECs while it was flow-dependent on arterial cells. Furthermore, analysis of HS/glycocalyx response after stimulation with inflammatory cues revealed that venous, but not arterial ECs, are resistant to HS shedding. This finding was observed also on isolated porcine vessels. Persistence of HS on venous ECs prevented complement deposition and clot formation after stimulation with tumor necrosis factor α or lipopolysaccharide, whereas after xenogeneic activation no glycocalyx-mediated protection was observed. Contrarily, HS shedding on arterial cells, even without an inflammatory insult, was sufficient to induce a proinflammatory and procoagulant phenotype. Our data indicate that the dimorphic response of arterial and venous ECs is partially due to distinct HS/glycocalyx dynamics suggesting that arterial and venous thrombo-inflammatory disorders require targeted therapies.

Mesenteric traction syndrome - Incidence, impact, and treatment: A systematic scoping review of the literature

BACKGROUND

Mesenteric traction syndrome (MTS) is commonly seen during major abdominal surgery and is characterised by facial flushing, hypotension, and tachycardia 15 min into surgery. MTS also impacts the postoperative course, as severe MTS has been associated with increased postoperative morbidity. However, despite MTS being common and severe MTS causing increased postoperative morbidity, the gaps in the literature are not clearly defined. We aimed to examine the diagnostic criteria, incidence, intraoperative and postoperative impact, and potential preventative measures of MTS while highlighting potential gaps in the literature.

METHODS

We followed the Prisma guidelines and performed a systematic literature search. We included only human studies examining MTS. All hits were screened for title and abstract, followed by a full-text review by at least two authors for determining eligibility for inclusion. Data were extracted and risk of bias was assessed by two independent reviewers.

RESULTS

A total of 37 studies, comprising 1102 patients were included in the review. The combined incidence of MTS during open abdominal surgery was found to be 76%, with 35% developing severe MTS. It was found that the development of MTS was associated with marked haemodynamic changes. It was also found that several different subjective diagnostic criteria exist and that severe MTS was associated with increased postoperative morbidity. Furthermore, several preventative measures for protecting against MTS have been examined, but only on the incidence of MTS and not on the postoperative course.

CONCLUSION

MTS occurs in 76% of patients undergoing major abdominal surgery and is associated with deleterious haemodynamic effects, which are more pronounced in patients developing severe MTS. Severe MTS is also associated with a worse postoperative outcome. However, gaps are still present in the current literature on MTS.

The Endothelial Glycocalyx and Neonatal Sepsis

Sepsis carries a substantial risk of morbidity and mortality in newborns, especially preterm-born neonates. Endothelial glycocalyx (eGC) is a carbohydrate-rich layer lining the vascular endothelium, with important vascular barrier function and cell adhesion properties, serving also as a mechano-sensor for blood flow. eGC shedding is recognized as a fundamental pathophysiological process generating microvascular dysfunction, which in turn contributes to multiple organ failure and death in sepsis. Although the disruption of eGC and its consequences have been investigated intensively in the adult population, its composition, development, and potential mechanisms of action are still poorly studied during the neonatal period, and more specifically, in neonatal sepsis. Further knowledge on this topic may provide a better understanding of the molecular mechanisms that guide the sepsis pathology during the neonatal period, and would increase the usefulness of endothelial glycocalyx dysfunction as a diagnostic and prognostic biomarker. We reviewed several components of the eGC that help to deeply understand the mechanisms involved in the eGC disruption during the neonatal period. In addition, we evaluated the potential of eGC components as biomarkers and future targets to develop therapeutic strategies for neonatal sepsis.

A Dietary Supplement Containing Fucoidan Preserves Endothelial Glycocalyx through ERK/MAPK Signaling and Protects against Damage Induced by CKD Serum

(1) Damage to the endothelial glycocalyx (eGC), a protective layer lining the endothelial luminal surface, is associated with chronic kidney disease (CKD), which leads to a worsening of cardiovascular outcomes in these patients. Currently, there are no targeted therapeutic approaches. Whether the dietary supplement Endocalyx^TM (ECX) protects against endothelial damage caused by uremic toxins is unknown. (2) We addressed this question by performing atomic force microscopy measurements on living endothelial cells. We examined the effect of ECX on eGC thickness at baseline and with pooled serum from hemodialysis patients. ECX was also successfully administered in vivo in mice, in which eGC was assessed using perfused boundary region measurements by intravital microscopy of cremasteric vessels. (3) Both ECX and fucoidan significantly improved baseline eGC thickness. Our data indicate that these effects are dependent on ERK/MAPK and PI3K signaling. After incubation with eGC damaging serum from dialysis patients, ECX increased eGC height. Intravital microscopy in mice revealed a relevant increase in baseline eGC dimensions after feeding with ECX. (4) We identified a dietary supplement containing glycocalyx substrates and fucoidan as potential mediators of eGC preservation in vitro and in vivo. Our findings suggest that fucoidan may be an essential component responsible for protecting the eGC in acute settings. Moreover, ECX might contribute to both protection and rebuilding of the eGC in the context of CKD.

Diosmin and its glycocalyx restorative and anti-inflammatory effects on injured blood vessels

The endothelium, a crucial homeostatic organ, regulates vascular permeability and tone. Under physiological conditions, endothelial stimulation induces vasodilator endothelial nitric oxide (eNO) release and prevents adhesion molecule accessibility and leukocyte adhesion and migration into vessel walls. Endothelium dysfunction is a principal event in cardiovascular disorders, including atherosclerosis. Minimal attention is given to an important endothelial cell structure, the endothelial glycocalyx (GCX), a negatively charged heterogeneous polysaccharide that serves as a protective covering for endothelial cells and enables endothelial cells to transduce mechanical stimuli into various biological and chemical activities. Endothelial GCX shedding thus plays a role in endothelial dysfunction, for example by increasing vascular permeability and decreasing vessel tone. Consequently, there is increasing interest in developing therapies that focus on GCX repair to limit downstream endothelium dysfunction and prevent further downstream cardiovascular events. Here, we present diosmin (3',5,7-trihydroxy-4'-methoxyflavone-7-rhamnoglucoside), a flavone glycoside of diosmetin, which downregulates adhesive molecule expression, decreases inflammation and capillary permeability, and upregulates eNO expression. Due to these pleiotropic effects of diosmin on the vasculature, a possible unidentified mechanism of action is through GCX restoration. We hypothesize that diosmin positively affects GCX integrity along with GCX-related endothelial functions. Our hypothesis was tested in a partial ligation left carotid artery (LCA) mouse model, where the right carotid artery was the control for each mouse. Diosmin (50 mg/kg) was administered daily for 7 days, 72 h after ligation. Within the ligated mice LCAs, diosmin treatment elevated the activated eNO synthase level, inhibited inflammatory cell uptake, decreased vessel wall thickness, increased vessel diameter, and increased GCX coverage of the vessel wall. ELISA showed a decrease in hyaluronan concentration in plasma samples of diosmin-treated mice, signifying reduced GCX shedding. In summary, diosmin supported endothelial GCX integrity, to which we attribute diosmin's preservation of endothelial function as indicated by attenuated expression of inflammatory factors and restored vascular tone.

Disturbed microcirculation and hyperaemic response in a murine model of systemic inflammation

Systemic inflammation affects cognitive functions and increases the risk of dementia. This phenomenon is thought to be mediated in part by cytokines that promote neuronal survival, but the continuous exposure to which may lead to neurodegeneration. The effects of systemic inflammation on cerebral blood vessels, and their provision of adequate oxygen to support critical brain parenchymal cell functions, remains unclear. Here, we demonstrate that neurovascular coupling is profoundly disturbed in lipopolysaccharide (LPS) induced systemic inflammation in awake mice. In the 24 hours following LPS injection, the hyperaemic response of pial vessels to functional activation was attenuated and delayed. Concurrently, under steady-state conditions, the capillary network displayed a significant increase in the number of capillaries with blocked blood flow, as well as increased duration of 'capillary stalls'-a phenomenon previously reported in animal models of stroke and Alzheimer's disease pathology. We speculate that vascular changes and impaired oxygen availability may affect brain functions following acute systemic inflammation and contribute to the long-term risk of neurodegenerative changes associated with chronic, systemic inflammation.

Form follows function: The endothelial glycocalyx

Three types of capillaries, namely continuous, fenestrated, and sinusoidal, form the microvascular system; each type has a specialized structure and function to respond to the demands of the organs they supply. The endothelial glycocalyx, a gel-like layer of glycoproteins that covers the luminal surface of the capillary endothelium, is also thought to maintain organ and vascular homeostasis by exhibiting different morphologies based on the functions of the organs and capillaries in which it is found. Recent advances in analytical technology have enabled more detailed observations of the endothelial glycocalyx, revealing that it indeed differs in structure across various organs. Furthermore, differences in the lectin staining patterns suggest the presence of different endothelial glycocalyx components across various organs. Interestingly, injury to the endothelial glycocalyx due to various pathologic and physiological stimuli causes the release of these components into the blood. Thus, circulating glycocalyx components may be useful biomarkers of organ dysfunction and disease severity. Moreover, a recent study suggested that chronic injury to the glycocalyx reduces the production of these glycocalyx components and changes their structure, leading it to become more vulnerable to external stimuli. In this review, we have summarized the various endothelial glycocalyx structures and their functions.

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.

The role of the cell surface glycocalyx in drug delivery to and through the endothelium

Cell membranes are key interfaces where materials engineering meets biology. Traditionally regarded as just the location of receptors regulating the uptake of molecules, we now know that all mammalian cell membranes are 'sugar coated'. These sugars, or glycans, form a matrix bound at the cell membrane via proteins and lipids, referred to as the glycocalyx, which modulate access to cell membrane receptors crucial for interactions with drug delivery systems (DDS). Focusing on the key blood-tissue barrier faced by most DDS to enable transport from the place of administration to target sites via the circulation, we critically assess the design of carriers for interactions at the endothelial cell surface. We also discuss the current challenges for this area and provide opportunities for future research efforts to more fully engineer DDS for controlled, efficient, and targeted interactions with the endothelium for therapeutic application.

Pharmacogenomics of Anti-TNF Treatment Response Marks a New Era of Tailored Rheumatoid Arthritis Therapy

Rheumatoid arthritis (RA) is the most commonly occurring chronic inflammatory arthritis, the exact mechanism of which is not fully understood. Tumor Necrosis Factor (TNF)-targeting drugs has been shown to exert high effectiveness for RA, which indicates the key importance of this cytokine in this disease. Nevertheless, the response to TNF inhibitors varies, and approximately one third of RA patients are non-responders, which is explained by the influence of genetic factors. Knowledge in the field of pharmacogenomics of anti-TNF drugs is growing, but has not been applied in the clinical practice so far. Different genome-wide association studies identified a few single nucleotide polymorphisms associated with anti-TNF treatment response, which largely map genes involved in T cell function. Studies of the gene expression profile of RA patients have also indicated specific gene signatures that may be useful to develop novel prognostic tools. In this article, we discuss the significance of TNF in RA and present the current knowledge in pharmacogenomics related to anti-TNF treatment response.

The Role of Heparin and Glycocalyx in Blood-Brain Barrier Dysfunction

The blood-brain barrier (BBB) functions as a dynamic boundary that protects the central nervous system from blood and plays an important role in maintaining the homeostasis of the brain. Dysfunction of the BBB is a pathophysiological characteristic of multiple neurologic diseases. Glycocalyx covers the luminal side of vascular endothelial cells(ECs). Damage of glycocalyx leads to disruption of the BBB, while inhibiting glycocalyx degradation maintains BBB integrity. Heparin has been recognized as an anticoagulant and it protects endothelial glycocalyx from destruction. In this review, we summarize the role of glycocalyx in BBB formation and the therapeutic potency of heparin to provide a theoretical basis for the treatment of neurological diseases related to BBB breakdown.

Selectin-targeting glycosaminoglycan-peptide conjugate limits neutrophil-mediated cardiac reperfusion injury

AIMS

One of the hallmarks of myocardial infarction (MI) is excessive inflammation. During an inflammatory insult, damaged endothelial cells shed their glycocalyx, a carbohydrate-rich layer on the cell surface which provides a regulatory interface to immune cell adhesion. Selectin-mediated neutrophilia occurs as a result of endothelial injury and inflammation. We recently designed a novel selectin-targeting glycocalyx mimetic (termed DS-IkL) capable of binding inflamed endothelial cells. This study examines the capacity of DS-IkL to limit neutrophil binding and platelet activation on inflamed endothelial cells, as well as the cardioprotective effects of DS-IkL after acute myocardial infarction.

METHODS AND RESULTS

In vitro, DS-IkL diminished neutrophil interactions with both recombinant selectin and inflamed endothelial cells, and limited platelet activation on inflamed endothelial cells. Our data demonstrated that DS-IkL localized to regions of vascular inflammation in vivo after 45 min of left anterior descending coronary artery ligation-induced MI. Further, findings from this study show DS-IkL treatment had short- and long-term cardioprotective effects after ischaemia/reperfusion of the left anterior descending coronary artery. Mice treated with DS-IkL immediately after ischaemia/reperfusion and 24 h later exhibited reduced neutrophil extravasation, macrophage accumulation, fibroblast and endothelial cell proliferation, and fibrosis compared to saline controls.

CONCLUSIONS

Our findings suggest that DS-IkL has great therapeutic potential after MI by limiting reperfusion injury induced by the immune response.

Endothelial Damage in Sepsis: The Importance of Systems Biology

The early diagnosis and appropriate stratification of sepsis continues to be one of the most important challenges in modern medicine. Single isolated biomarkers have not been enough to improve diagnostic and prognostic strategies and to progress toward therapeutic goals. The information generated by the human genome project has allowed a more holistic approach to the problem. The integration of genomics, transcriptomics, proteomics and metabolomics in sepsis has allowed us to progress in the knowledge of new pathways which are pathophysiologically involved in this disease. Thus, we have understood the importance of and complex interaction between the inflammatory response and the endothelium. Understanding the role of important parts of the microcirculation, such as the endothelial glycocalyx and its interaction with the inflammatory response, has provided early recognition elements for clinical practice that allow the rational use of traditional medical interventions in sepsis. This comprehensive approach, which differs from the classical mechanistic approach, uses systems biology to increase the diagnostic and prognostic spectrum of endothelial damage biomarkers in sepsis, and to provide information on new pathways involved in the pathophysiology of the disease. This, in turn, provides tools for perfecting traditional medical interventions, using them at the appropriate times according to the disease's pathophysiological context, while at the same time discovering new and improved therapeutic alternatives. We have the challenge of transferring this ideal scenario to our daily clinical practice to improve our patients' care. The purpose of this article is to provide a general description of the importance of systems biology in integrating the complex interaction between the endothelium and the inflammatory response in sepsis.

Endothelial dysfunction in preterm infants: The hidden legacy of uteroplacental pathologies

Millions of infants are born prematurely every year worldwide. Prematurity, particularly at lower gestational ages, is associated with high mortality and morbidity and is a significant global health burden. Pregnancy complications and preterm birth syndrome strongly impact neonatal clinical phenotypes and outcomes. The vascular endothelium is a pivotal regulator of fetal growth and development. In recent years, the key role of uteroplacental pathologies impairing endothelial homeostasis is emerging. Conditions leading to very and extremely preterm birth can be classified into two main pathophysiological patterns or endotypes: infection/inflammation and dysfunctional placentation. The first is frequently related to chorioamnionitis, whereas the second is commonly associated with hypertensive disorders of pregnancy and fetal growth restriction. The nature, timing, and extent of prenatal noxa may alter fetal and neonatal endothelial phenotype and functions. Changes in the luminal surface, oxidative stress, growth factors imbalance, and dysregulation of permeability and vascular tone are the leading causes of endothelial dysfunction in preterm infants. However, the available evidence regarding endothelial physiology and damage is limited in neonates compared to adults. Herein, we discuss the current knowledge on endothelial dysfunction in the infectious/inflammatory and dysfunctional placentation endotypes of prematurity, summarizing their molecular features, available biomarkers, and clinical impact. Furthermore, knowledge gaps, shadows, and future research perspectives are highlighted.

Gunanti Soeyono DV, Bardosono S, Jusman S, Siagian M, Lubis M. Resuscitation of hemorrhagic shock using normal saline does not damage the glycocalyx in the immediate resuscitation phase

OBJECTIVES:

The objectives were to study the effect of aggressive resuscitation using normal saline on hemodynamics, serum atrial natriuretic peptide (ANP), syndecan-1 (marker of endothelial glycocalyx shedding), and extravascular lung water index (ELWI) following hemorrhagic shock.

METHODS:

Eleven male piglets (Sus scrofa) underwent blood drawing to create 20% drop in mean arterial pressure (MAP). Two-phase resuscitation was performed: Phase 1 using normal saline of an equal volume of blood drawn to create shock and Phase 2 using 40 ml/kg BW of normal saline to simulate hypervolemia and hemodilution. Heart rate, MAP, cardiac index (CI), systemic vascular resistance index, oxygen delivery (DO₂), global end-diastolic volume index, ELWI, hemoglobin (Hb), lactate, ANP, and syndecan-1 at each phase and up to 60 min following Phase 2 resuscitation were recorded.

RESULTS:

Phase 2 resuscitation significantly decreased Hb concentration (P = 0.006), however, DO₂ was maintained (P = 1.000). CI increased from shock to Phase 1 (P = 0.029) and further increase in Phase 2 resuscitation (P = 0.001). Overall, there was a transient increase of ANP following Phase 1 resuscitation, from 85.20 ± 40.86 ng/L at baseline to 106.42 ± 33.71 ng/L (P = 0.260). Serum syndecan-1 and ELWI change at all phases were not significant.

CONCLUSIONS:

We demonstrate compensatory protective mechanism despite overzealous fluid resuscitation. Compensatory increased CI despite decreased Hb maintained DO₂. In the absence of inflammation, serum ANP did not increase significantly, no glycocalyx shedding occurred, subsequently no change in ELWI. We show that factors other than volume overload are more dominant in causing glycocalyx shedding.

Endothelial glycocalyx degradation during sepsis: Causes and consequences

•

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.

Diagnosing capillary leak in critically ill patients: development of an innovative scoring instrument for non-invasive detection

BACKGROUND

The concomitant occurrence of the symptoms intravascular hypovolemia, peripheral edema and hemodynamic instability is typically named Capillary Leak Syndrome (CLS) and often occurs in surgical critical ill patients. However, neither a unitary definition nor standardized diagnostic criteria exist so far. We aimed to investigate common characteristics of this phenomenon with a subsequent scoring system, determining whether CLS contributes to mortality.

METHODS

We conducted this single-center, observational, multidisciplinary, prospective trial in two separately run surgical ICUs of a tertiary academic medical center. 200 surgical patients admitted to the ICU and 30 healthy volunteers were included. Patients were clinically diagnosed as CLS or No-CLS group (each N = 100) according to the grade of edema, intravascular hypovolemia, hemodynamic instability, and positive fluid balance by two independent attending physicians with > 10 years of experience in ICU. We performed daily measurements with non-invasive body impedance electrical analysis, ultrasound and analysis of serum biomarkers to generate objective diagnostic criteria. Receiver operating characteristics were used, while we developed machine learning models to increase diagnostic specifications for our scoring model.

RESULTS

The 30-day mortility was increased among CLS patients (12 vs. 1%, P = 0.002), while showing higher SOFA-scores. Extracellular water was increased in patients with CLS with higher echogenicity of subcutaneous tissue [29(24-31) vs. 19(16-21), P < 0.001]. Biomarkers showed characteristic alterations, especially with an increased angiopoietin-2 concentration in CLS [9.9(6.2-17.3) vs. 3.7(2.6-5.6)ng/mL, P < 0.001]. We developed a score using seven parameters (echogenicity, SOFA-score, angiopoietin-2, syndecan-1, ICAM-1, lactate and interleukin-6). A Random Forest prediction model boosted its diagnostic characteristics (AUC 0.963, P < 0.001), while a two-parameter decision tree model showed good specifications (AUC 0.865).

CONCLUSIONS

Diagnosis of CLS in critically ill patients is feasible by objective, non-invasive parameters using the CLS-Score. A simplified two-parameter diagnostic approach can enhance clinical utility. CLS contributes to mortality and should, therefore, classified as an independent entity.

TRIAL REGISTRATION

German Clinical Trials Registry (DRKS No. 00012713), Date of registration 10/05/2017, www.drks.de.

Syndecan-1, an indicator of endothelial glycocalyx degradation, predicts outcome of patients admitted to an ICU with COVID-19

Background

We investigated the feasibility of two biomarkers of endothelial damage (Syndecan-1 and thrombomodulin) in coronavirus disease 2019 (COVID-19), and their association with inflammation, coagulopathy, and mortality.

Methods

The records of 49 COVID-19 patients who were admitted to an intensive care unit (ICU) in Wuhan, China between February and April 2020 were examined. Demographic, clinical, and laboratory data, and outcomes were compared between survivors and non-survivors COVID-19 patients, and between patients with high and low serum Syndecan-1 levels. The dynamics of serum Syndecan-1 levels were also analyzed.

Results

The levels of Syndecan-1 were significantly higher in non-survivor group compared with survivor group (median 1031.4 versus 504.0 ng/mL, P = 0.002), and the levels of thrombomodulin were not significantly different between these two groups (median 4534.0 versus 3780.0 ng/mL, P = 0.070). Kaplan–Meier survival analysis showed that the group with high Syndecan-1 levels had worse overall survival (log-rank test: P = 0.023). Patients with high Syndecan-1 levels also had significantly higher levels of thrombomodulin, interleukin-6, and tumor necrosis factor-α. Data on the dynamics of Syndecan-1 levels indicated much greater variations in non-survivors than survivors.

Conclusions

COVID-19 patients with high levels of Syndecan-1 develop more serious endothelial damage and inflammatory reactions, and have increased mortality. Syndecan-1 has potential for use as a marker for progression or severity of COVID-19. Protecting the glycocalyx from destruction is a potential treatment for COVID-19.

Supplementary Information

The online version contains supplementary material available at 10.1186/s10020-021-00412-1.

Protection and rebuilding of the endothelial glycocalyx in sepsis - Science or fiction?

The endothelial glycocalyx (eGC), a delicate carbohydrate-rich structure lining the luminal surface of the vascular endothelium, is vital for maintenance of microvascular homeostasis. In sepsis, damage of the eGC triggers the development of vascular hyperpermeability with consecutive edema formation and organ failure. While there is evidence that protection or rebuilding of the eGC might counteract sepsis-induced vascular leakage and improve outcome, approved therapeutics are not yet available. This narrative review aims to outline possible therapeutic strategies to ameliorate organ dysfunction caused by eGC impairment.

Effects of therapeutic plasma exchange on the endothelial glycocalyx in septic shock

Background

Disruption of the endothelial glycocalyx (eGC) is observed in septic patients and its injury is associated with multiple-organ failure and inferior outcomes. Besides this biomarker function, increased blood concentrations of shedded eGC constituents might play a mechanistic role in septic organ failure. We hypothesized that therapeutic plasma exchange (TPE) using fresh frozen plasma might influence eGC-related pathology by removing injurious mediators of eGC breakdown while at the time replacing eGC protective factors.

Methods

We enrolled 20 norepinephrine-dependent (NE > 0.4 μg/kg/min) patients with early septic shock (onset < 12 h). Sublingual assessment of the eGC via sublingual sidestream darkfield (SDF) imaging was performed. Plasma eGC degradation products, such as heparan sulfate (HS) and the eGC-regulating enzymes, heparanase (Hpa)-1 and Hpa-2, were obtained before and after TPE. A 3D microfluidic flow assay was performed to examine the effect of TPE on eGC ex vivo. Results were compared to healthy controls.

Results

SDF demonstrated a decrease in eGC thickness in septic patients compared to healthy individuals (p = 0.001). Circulating HS levels were increased more than sixfold compared to controls and decreased significantly following TPE [controls: 16.9 (8–18.6) vs. septic patients before TPE: 105.8 (30.8–143.4) μg/ml, p < 0.001; vs. after TPE: 70.7 (36.9–109.5) μg/ml, p < 0.001]. The Hpa-2 /Hpa-1 ratio was reduced in septic patients before TPE but normalized after TPE [controls: 13.6 (6.2–21.2) vs. septic patients at inclusion: 2.9 (2.1–5.7), p = 0.001; vs. septic patients after TPE: 13.2 (11.2–31.8), p < 0.001]. Ex vivo stimulation of endothelial cells with serum from a septic patient induced eGC damage that could be attenuated with serum from the same patient following TPE.

Conclusions

Septic shock results in profound degradation of the eGC and an acquired deficiency of the protective regulator Hpa-2. TPE removed potentially injurious eGC degradation products and partially attenuated Hpa-2 deficiency.

Trial registration clinicaltrials.gov NCT04231994, retrospectively registered 18 January 2020

Supplementary Information

The online version contains supplementary material available at 10.1186/s40635-021-00417-4.