Heparanase Mediates Intestinal Inflammation and Injury in a Mouse Model of Sepsis

Low-molecular-weight heparin ameliorates intestinal barrier dysfunction in aged male rats via protection of tight junction proteins

The intestinal barrier weakens and chronic gut inflammation occurs in old age, causing age-related illnesses. Recent research shows that low-molecular-weight heparin (LMWH), besides anticoagulation, also has anti-inflammatory and anti-apoptotic effects, protecting the intestinal barrier. This study aims to analyze the effect of LMWH on the intestinal barrier of old male rodents. This study assigned Sprague-Dawley male rats to four groups: young (3 months), young + LMWH, old (20 months), and old + LMWH. The LMWH groups received 1 mg/kg LMWH via subcutaneous injection for 7 days. Optical and transmission electron microscopy (TEM) were used to examine morphological changes in intestinal mucosa due to aging. Intestinal permeability was measured using fluorescein isothiocyanate (FITC)-dextran. ELISA kits were used to measure serum levels of IL-6 and IL-1β, while Quantitative RT-PCR detected their mRNA levels in intestinal tissues. Western blotting and immunohistochemistry (IHC) evaluated the tight junction (TJ) protein levels such as occludin, zonula occludens-1 (ZO-1), and claudin-2. Western blotting assessed the expression of the apoptosis marker cleaved caspase 3, while IHC was used to detect LGR5+ intestinal stem cells. The intestinal permeability of aged rats was significantly higher than that of young rats, indicating significant differences. With age, the protein levels of occludin and ZO-1 decreased significantly, while the level of claudin-2 increased significantly. Meanwhile, our study found that the levels of IL-1β and IL-6 increased significantly with age. LMWH intervention effectively alleviated age-related intestinal barrier dysfunction. In aged rats treated with LMWH, the expression of occludin and ZO-1 proteins in the intestine increased, while the expression of claudin-2 decreased. Furthermore, LMWH administration in aged rats resulted in a decrease in IL-1β and IL-6 levels. LMWH also reduced age-related cleaved caspase3 expression, but IHC showed no difference in LGR5+ intestinal stem cells between groups. Research suggests that LMWH could potentially be a favorable therapeutic choice for age-related diseases associated with intestinal barrier dysfunction, by protecting TJ proteins, reducing inflammation, and apoptosis.

Cascading renal injury after brain death: Unveiling glycocalyx alteration and the potential protective role of tacrolimus

Brain death (BD) is a complex medical state that triggers systemic disturbances and a cascade of pathophysiological processes. This condition significantly impairs both kidney function and structural integrity, thereby presenting considerable challenges to graft viability and the long-term success of transplantation endeavors. Tacrolimus (FK506), an immunosuppressive drug, was used in this study to assess its impact as a pretreatment on brain death-induced renal injury. This study aimed to investigate changes associated with brain death-induced renal injury in a 4-month-old female porcine model. The experimental groups included brain death placebo-pretreated (BD; n = 9), brain death tacrolimus-pretreated using the clinical dose of 0.25 mg/kg the day before surgery, followed by 0.05 mg/kg/day 1 hour before the procedure (BD + FK506; n = 8), and control (ctrl, n = 7) piglets, which did not undergo brain death induction. Furthermore, we aimed to assess the effect of FK506 on these renal alterations through graft preconditioning. We hypothesized that immunosuppressive properties of FK506 reduce tissue inflammation and preserve the glycocalyx. Our findings revealed a series of interconnected events triggered by BD, leading to a deterioration of renal function and increased proteinuria, increased apoptosis in the vessels, glomeruli and tubules, significant leukocyte infiltration into renal tissue, and degradation of the glycocalyx in comparison with ctrl group. Importantly, treatment with FK506 demonstrated significant efficacy in attenuating these adverse effects. FK506 helped reduce apoptosis, maintain glycocalyx integrity, regulate neutrophil infiltration, and mitigate renal injury following BD. This study offers new insights into the pathophysiology of BD-induced renal injury, emphasizing the potential of FK506 pretreatment as a promising therapeutic intervention for organ preservation, through maintaining endothelial function with the additional benefit of limiting the risk of rejection.

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.

Relationship between low molecular weight heparin calcium therapy and prognosis in severe acute kidney injury in sepsis: Mendelian randomized analysis and retrospective study

Background

Sepsis-associated acute kidney injury (SA-AKI) poses an independent risk for mortality due to the absence of highly sensitive biomarkers and a specific treatment plan.

Objective

Investigate the association between low molecular weight heparin (LMWH) calcium therapy and prognosis in critically ill SA-AKI patients, and assess the causal relationship through Mendelian randomization (MR) analysis.

Methods

A single-center, retrospective, cross-sectional study included 90 SA-AKI patients and 30 septic patients without acute kidney injury (AKI) from the intensive care unit (ICU) of the First Hospital of Lanzhou University. SA-AKI patients were categorized into control or LMWH groups based on LMWH calcium usage. Primary outcome was renal function recovery, with secondary outcomes including 28-day mortality, ICU stay length, number of renal replacement therapy (RRT) recipients, and 90-day survival. MR and related sensitivity analyses explored causal effects.

Results

The combination of heparin-binding protein (HBP), heparanase (HPA), and neutrophil gelatinase-associated lipocalin (NGAL) demonstrated high diagnostic value for SA-AKI. MR analysis suggested a potential causal link between gene-predicted HBP and AKI (OR: 1.369, 95%CI: 1.040-1.801, p = 0.024). In the retrospective study, LMWH-treated patients exhibited improved renal function, reduced levels of HPA, HBP, Syndecan-1, and inflammation, along with enhanced immune function compared to controls. However, LMWH did not impact 28-day mortality, 90-day survival, or ICU stay length.

Conclusion

LMWH could enhance renal function in SA-AKI patients. MR analysis supports this causal link, underscoring the need for further validation in randomized controlled trials.

Role of heparanase in sepsis‑related acute kidney injury (Review)

Sepsis-related acute kidney injury (S-AKI) is a common and significant complication of sepsis in critically ill patients, which can often only be treated with antibiotics and medications that reduce S-AKI symptoms. The precise mechanism underlying the onset of S-AKI is still unclear, thus hindering the development of new strategies for its treatment. Therefore, it is necessary to explore the pathogenesis of S-AKI to identify biomarkers and therapeutic targets for its early diagnosis and treatment. Heparanase (HPA), the only known enzyme that cleaves the side chain of heparan sulfate, has been widely studied in relation to tumor metabolism, procoagulant activity, angiogenesis, inflammation and sepsis. It has been reported that HPA plays an important role in the progression of S-AKI. The aim of the present review was to provide an overview of the function of HPA in S-AKI and to summarize its underlying molecular mechanisms, including mediating inflammatory response, immune response, autophagy and exosome biogenesis. It is anticipated that emerging discoveries about HPA in S-AKI will support HPA as a potential biomarker and therapeutic target to combat S-AKI.

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.

Role of heparanase in ARDS through autophagy and exosome pathway (review)

Acute respiratory distress syndrome (ARDS) is the most common respiratory disease in ICU. Although there are many treatment and support methods, the mortality rate is still high. The main pathological feature of ARDS is the damage of pulmonary microvascular endothelium and alveolar epithelium caused by inflammatory reaction, which may lead to coagulation system disorder and pulmonary fibrosis. Heparanase (HPA) plays an significant role in inflammation, coagulation, fibrosis. It is reported that HPA degrades a large amount of HS in ARDS, leading to the damage of endothelial glycocalyx and inflammatory factors are released in large quantities. HPA can aggrandize the release of exosomes through syndecan-syntenin-Alix pathway, leading to a series of pathological reactions; at the same time, HPA can cause abnormal expression of autophagy. Therefore, we speculate that HPA promotes the occurrence and development of ARDS through exosomes and autophagy, which leads to a large amount of release of inflammatory factors, coagulation disorder and pulmonary fibrosis. This article mainly describes the mechanism of HPA on ARDS.

The role of the alveolar epithelial glycocalyx in acute respiratory distress syndrome

The alveolar epithelial glycocalyx is a dense anionic layer of glycosaminoglycans (GAGs) and proteoglycans that lines the apical surface of the alveolar epithelium. In contrast to the pulmonary endothelial glycocalyx, which has well-established roles in vascular homeostasis and septic organ dysfunction, the alveolar epithelial glycocalyx is less understood. Recent preclinical studies demonstrated that the epithelial glycocalyx is degraded in multiple murine models of acute respiratory distress syndrome (ARDS), particularly those that result from inhaled insults (so-called "direct" lung injury), leading to shedding of GAGs into the alveolar airspaces. Epithelial glycocalyx degradation also occurs in humans with respiratory failure, as quantified by analysis of airspace fluid obtained from ventilator heat moisture exchange (HME) filters. In patients with ARDS, GAG shedding correlates with the severity of hypoxemia and is predictive of the duration of respiratory failure. These effects may be mediated by surfactant dysfunction, as targeted degradation of the epithelial glycocalyx in mice was sufficient to cause increased alveolar surface tension, diffuse microatelectasis, and impaired lung compliance. In this review, we describe the structure of the alveolar epithelial glycocalyx and the mechanisms underlying its degradation during ARDS. We additionally review the current state of knowledge regarding the attributable effect of epithelial glycocalyx degradation in lung injury pathogenesis. Finally, we address glycocalyx degradation as a potential mediator of ARDS heterogeneity, and the subsequent value of point-of-care quantification of GAG shedding to potentially identify patients who are most likely to respond to pharmacological agents aimed at attenuating glycocalyx degradation.

Heparin, Heparan Sulphate and Sepsis: Potential New Options for Treatment

Sepsis is a life-threatening hyperreaction to infection in which excessive inflammatory and immune responses cause damage to host tissues and organs. The glycosaminoglycan heparan sulphate (HS) is a major component of the cell surface glycocalyx. Cell surface HS modulates several of the mechanisms involved in sepsis such as pathogen interactions with the host cell and neutrophil recruitment and is a target for the pro-inflammatory enzyme heparanase. Heparin, a close structural relative of HS, is used in medicine as a powerful anticoagulant and antithrombotic. Many studies have shown that heparin can influence the course of sepsis-related processes as a result of its structural similarity to HS, including its strong negative charge. The anticoagulant activity of heparin, however, limits its potential in treatment of inflammatory conditions by introducing the risk of bleeding and other adverse side-effects. As the anticoagulant potency of heparin is largely determined by a single well-defined structural feature, it has been possible to develop heparin derivatives and mimetic compounds with reduced anticoagulant activity. Such heparin mimetics may have potential for use as therapeutic agents in the context of sepsis.

Evaluation of Immunohistochemical Expression of Heparanase in Helicobacter pylori-Associated Chronic Gastritis

Background

Chronic gastritis (CG) is a very common disease. More than half of the worldwide population suffers from symptoms of CG. This disease has received great attention since the discovery of H. pylori as the most important cause of CG. Symptoms experienced by patients with CG are attributed to H. pylori-induced inflammatory reactions. Heparanase (HPSE) is a mammalian β-endoglucoronidase. In inflammation; HPSE degrades and remodels the extracellular matrix's heparan sulfate polysaccharide chains liberating heparan sulfate-bound cytokines and chemokines, HPSE also facilitates movement of inflammatory cells.

Aims

This study aimed to detect the function of HPSE in CG by correlating levels of HPSE expression with histopathological features of CG, including H. pylori infection, acute and chronic inflammatory cells, mucosal atrophic and/or metaplastic features.

Methods

Ninety-five upper endoscopic-guided gastric punch biopsies were enrolled in this study. From each specimen, formalin-fixed and paraffin-embedded tissue blocks were prepared. Tissue sections were stained by Hematoxylin and eosin, Giemsa, and anti-heparanase antibody.

Results

HPSE expression was statistically associated with H. pylori infection (P-value < .000), and intensity of chronic lymphocytic inflammatory infiltrate in the gastric mucosal tissues (P = .004). High levels of HPSE expression were also related to the presence of neutrophils in the gastric surface epithelium and lamina propria (P-value < .009).

Conclusions

HPSE expression was upregulated in H. pylori-associated chronic gastritis. Thus, future therapeutic agents that could specifically inhibit HPSE enzyme activity, may aid in the reduction of sequelae of H. pylori infection.

Heparanase: A Novel Therapeutic Target for the Treatment of Atherosclerosis

Cardiovascular disease (CVD) is the leading cause of death and disability worldwide, and its management places a huge burden on healthcare systems through hospitalisation and treatment. Atherosclerosis is a chronic inflammatory disease of the arterial wall resulting in the formation of lipid-rich, fibrotic plaques under the subendothelium and is a key contributor to the development of CVD. As such, a detailed understanding of the mechanisms involved in the development of atherosclerosis is urgently required for more effective disease treatment and prevention strategies. Heparanase is the only mammalian enzyme known to cleave heparan sulfate of heparan sulfate proteoglycans, which is a key component of the extracellular matrix and basement membrane. By cleaving heparan sulfate, heparanase contributes to the regulation of numerous physiological and pathological processes such as wound healing, inflammation, tumour angiogenesis, and cell migration. Recent evidence suggests a multifactorial role for heparanase in atherosclerosis by promoting underlying inflammatory processes giving rise to plaque formation, as well as regulating lesion stability. This review provides an up-to-date overview of the role of heparanase in physiological and pathological processes with a focus on the emerging role of the enzyme in atherosclerosis.

Xylan Prebiotics and the Gut Microbiome Promote Health and Wellbeing: Potential Novel Roles for Pentosan Polysulfate

This narrative review highlights the complexities of the gut microbiome and health-promoting properties of prebiotic xylans metabolized by the gut microbiome. In animal husbandry, prebiotic xylans aid in the maintenance of a healthy gut microbiome. This prevents the colonization of the gut by pathogenic organisms obviating the need for dietary antibiotic supplementation, a practice which has been used to maintain animal productivity but which has led to the emergence of antibiotic resistant bacteria that are passed up the food chain to humans. Seaweed xylan-based animal foodstuffs have been developed to eliminate ruminant green-house gas emissions by gut methanogens in ruminant animals, contributing to atmospheric pollution. Biotransformation of pentosan polysulfate by the gut microbiome converts this semi-synthetic sulfated disease-modifying anti-osteoarthritic heparinoid drug to a prebiotic metabolite that promotes gut health, further extending the therapeutic profile and utility of this therapeutic molecule. Xylans are prominent dietary cereal components of the human diet which travel through the gastrointestinal tract as non-digested dietary fibre since the human genome does not contain xylanolytic enzymes. The gut microbiota however digest xylans as a food source. Xylo-oligosaccharides generated in this digestive process have prebiotic health-promoting properties. Engineered commensal probiotic bacteria also have been developed which have been engineered to produce growth factors and other bioactive factors. A xylan protein induction system controls the secretion of these compounds by the commensal bacteria which can promote gut health or, if these prebiotic compounds are transported by the vagal nervous system, may also regulate the health of linked organ systems via the gut–brain, gut–lung and gut–stomach axes. Dietary xylans are thus emerging therapeutic compounds warranting further study in novel disease prevention protocols.

Serum Syndecan-1 levels in patients with immunoglobulin A vasculitis in children

OBJECTIVE

The aim of this study was to evaluate the serum Syndecan-1 (SDC-1) levels in patients with immunoglobulin-A vasculitis (IgAV) in children and its relation with gastrointestinal involvements.

METHODS

Sixty-eight children with IgAV and 48 healthy children were enrolled in this cross-sectional study. Clinical and related laboratory data were collected from a computerized hospital database. Serum SDC-1 was collected on admission prior to treatment.

RESULTS

Forty-eight patients fully met the IgAV diagnostic criteria at admission (IgAV group), 20 patients with rash only and diagnosed IgAV during hospitalization (Purpura group). In IgAV group, 30 patients with gastrointestinal involvements (IgAV-GI group) and 18 patients without gastrointestinal involvements (IgAV-NGI group). SDC-1 serum levels were significantly higher in the IgAV group (86.37 ng/mL (IQR 59.16-117.14 ng/mL)) than in the controls (20.37 ng/mL (IQR 15.52-26.45 ng/mL)) and the Purpura group (32.66 ng/mL (IQR 14.87-49.89 ng/mL)). Additionally, SDC-1 (OR = 1.08) was independently associated with IgAV with a cut-off value (sensitivity and specificity) of 66.55 ng/mL (68.8%, 95.0%), and the area under the curve was 0.908. The serum SDC-1 levels of the IgAV-GI group (106.92 ± 50.12 ng/mL) were significantly higher than those in the IgAV-NGI group (67.52 ± 17.59 ng/mL). Logistic regression analysis showed that SDC-1 (OR = 1.03) was independently associated with IgAV-GI with a cut-off value of 89.39 ng/mL.

CONCLUSIONS

SDC-1 serum levels may mirror vascular endothelium injury and mucosal damage in IgAV. Its applicability as a surrogate biomarker in IgAV remains to be determined.

Effects of Shenling Chengqi Decoction on Gastrointestinal Function and Immune Status of Patients with Gastrointestinal Injury in Severe Sepsis

Objective

To investigate the effects of Shenling Chengqi decoction combined with routine treatment on gastrointestinal function and immune status of patients with gastrointestinal injury in severe sepsis.

Methods

160 patients with sepsis were randomly divided into a control group (n = 80) and observation group (n = 80). The control group was given routine treatment such as anti-infection and vasoactive drugs. The observation group was treated with Shenling Chengqi decoction on the basis of routine treatment for 7 days. The improvement of gastrointestinal symptoms, nutritional status, gastrointestinal dynamics, inflammatory response, and immune function was observed before and after treatment. The outcome indicators were evaluation of gastrointestinal symptoms, evaluation of disease severity, nutritional status, gastrointestinal dynamic indexes, inflammatory indexes, and immune function indexes. SPSS 22.0 statistical software was used for data processing. The paired t-test was used for comparison before and after treatment.

Results

Compared with the control group, the disappearance time of reflux, vomiting, and recovery time of bowel sounds in the observation group were significantly shorter (P < 0.05), and the number of defecation per day was significantly higher than that in the control group (P < 0.05). After 3 and 7 days of treatment, the APACHE II score, SIRS score, serum gas, IgA, IgM, serum hs-CRP, TNF, and PCT of the two groups were significantly lower than those before treatment (P < 0.05), and the scores of the observation group were significantly lower than those of the control group (P < 0.05). The levels of SS and MOT were significantly higher than those before treatment (P < 0.05). After 7 days of treatment, the levels of serum Hb, ALB, and PA in the two groups were significantly higher than those before treatment (P < 0.05), and the nutritional status in the observation group was significantly higher than that in the control group (P < 0.05).

Conclusion

Shenling Chengqi decoction can effectively improve gastrointestinal symptoms, nutritional status, and gastrointestinal dynamics in patients with sepsis. It has high safety and is worthy of clinical promotion.

Balancing Microthrombosis and Inflammation via Injectable Protein Hydrogel for Inflammatory Bowel Disease

Emerging evidence indicates that a vicious cycle between inflammation and microthrombosis catalyzes the pathogenesis of inflammatory bowel disease (IBD). Over-stimulated inflammation triggers a coagulation cascade and leads to microthrombosis, which further complicates the injury through tissue hypoxia and ischemia. Herein, an injectable protein hydrogel with anti-thrombosis and anti-inflammation competency is developed to impede this cycle, cross-linked by silver ion mediated metal-ligand coordination and electronic interaction with sulfhydryl functionalized bovine serum albumin and heparin, respectively. The ex vivo experiments show that the hydrogel, HEP-Ag-BSA, exhibits excellent self-healing ability, injectability, biocompatibility, and sustained drug release. HEP-Ag-BSA also demonstrates anti-coagulation and anti-inflammation abilities via coagulation analysis and lipopolysaccharide stimulation assay. The in vivo imaging confirms the longer retention time of HEP-Ag-BSA at inflammatory sites than in normal mucosa owing to electrostatic interactions. The in vivo study applying a mouse model with colitis also reveals that HEP-Ag-BSA can robustly inhibit inflammatory microthrombosis with reduced bleeding risk. This versatile protein hydrogel platform can definitively hinder the "inflammation and microthrombosis" cycle, providing a novel integrated approach against IBD.

Glycocalyx heparan sulfate cleavage promotes endothelial cell angiopoietin-2 expression by impairing shear stress-related AMPK/FoxO1 signaling

Angiopoietin-2 (Ang-2) is a key mediator of vascular disease during sepsis, and elevated plasma levels of Ang-2 are associated with organ injury scores and poor clinical outcomes. We have previously observed that biomarkers of endothelial glycocalyx (EG) damage correlate with plasma Ang-2 levels, suggesting a potential mechanistic linkage between EG injury and Ang-2 expression during states of systemic inflammation. However, the cell signaling mechanisms regulating Ang-2 expression following EG damage are unknown. In the current study, we determined the temporal associations between plasma heparan sulfate (HS) levels as a marker of EG erosion and plasma Ang-2 levels in children with sepsis and in mouse models of sepsis. Secondly, we evaluated the role of shear stress-mediated 5'-adenosine monophosphate-activated protein kinase (AMPK) signaling in Ang-2 expression following enzymatic HS cleavage from the surface of human primary lung microvascular endothelial cells (HLMVEC). We found that plasma HS levels peak prior to plasma Ang-2 levels in children and mice with sepsis. Further, we discovered that impaired AMPK signaling contributes to increased Ang-2 expression following HS cleavage from flow conditioned HLMVECs, establishing a novel paradigm by which Ang-2 may be upregulated during sepsis.

Utility of CD138/syndecan-1 immunohistochemistry for localization of plasmacytes is tissue-dependent in B6 mice

Objective

Inflammation is present in many diseases and identification of immune cell infiltration is a common assessment. CD138 (syndecan-1) is a recommended immunohistochemical marker for human plasmacytes although it is also expressed in various epithelia and tumors. Similarly, CD138 is a marker for murine plasmacytes, but its tissue immunostaining is not well-defined. Endogenous CD138 expression is an important confounding factor when evaluating plasmacyte infiltration. We studied two plasmacyte markers (CD138 and Kappa light chains) for endogenous immunostaining in five organs and one tumor from B6 mice.

Results

Plasmacytes in Peyer’s patches were positive for CD138 and Kappa markers without endogenous immunostaining. Endogenous CD138 immunostaining was widespread in liver, kidney, lung and a malignant peripheral nerve sheath tumor (MPNST) versus regionalized immunostaining in skin and small intestine wall. Endogenous Kappa immunostaining was absent in all tissues except for plasmacytes. Tissues with widespread endogenous CD138 immunostaining were contrasted by absence of endogenous Kappa immunostaining. Here, plasmacytes would not be distinguished by CD138, but would be obvious by Kappa immunostaining. Our study suggests that utility of immunostaining for plasmacytes by CD138 is tissue dependent in mice. Additionally, Kappa immunostaining may be a useful alternative in mouse tissues with confounding endogenous CD138 immunostaining.

Utilization of glycosaminoglycans by the human gut microbiota: participating bacteria and their enzymatic machineries

Glycosaminoglycans (GAGs) are consistently present in the human colon in free forms and as part of proteoglycans. Their utilization is critical for the colonization and proliferation of gut bacteria and also the health of hosts. Hence, it is essential to determine the GAG-degrading members of the gut bacteria and their enzymatic machinery for GAG depolymerization. In this review, we have summarized the reported GAG utilizers from Bacteroides and presented their polysaccharide utilization loci (PUL) and related enzymatic machineries for the degradation of chondroitin and heparin/heparan sulfate. Although similar comprehensive knowledge of GAG degradation is not available for other gut phyla, we have specified recently isolated GAG degraders from gut Firmicutes and Proteobacteria, and analyzed their genomes for the presence of putative GAG PULs. Deciphering the precise GAG utilization mechanism for various phyla will augment our understanding of their effects on human health.

Emerging role of syndecans in maintaining homeostasis of colon epithelium during inflammation

The syndecans are a family of transmembrane proteoglycans that are widespread in mammalian tissues. Located at the cell surface membrane, they contribute to modulating the composition of the extracellular matrix via glycosaminoglycan chains (GAGs) attached to their extracellular domains. Syndecans can interact with a variety of extracellular ligands through their core proteins and GAGs, and may also transmit signals through their transmembrane domain to regulate intracellular functions. These properties enable syndecan to modulate glycocalyx formation, epithelial cell-to-cell connections for cell barrier formation, and epithelial cell-lamina propria interactions in the colon epithelium, all of which are crucial for the homeostasis of this tissue. Inflammation induces structural alterations of the colon epithelium, and accumulating evidence suggests that syndecan expression might play important regulatory functions during inflammation. This review summarizes the possible roles of syndecans in maintaining tissue homeostasis in the colon epithelium, especially under inflammation.

Role of heparinase in the gastrointestinal dysfunction of sepsis (Review)

Heparinase (HPA) is a β-D glucuronidase that belongs to the endoglycosidase enzyme family, and plays an important role in numerous pathological and physiological processes, including inflammation, angiogenesis and tumor metastasis. When the expression of HPA is abnormally high, the side chain of heparin sulfate proteoglycans degrades, destroying the cell barrier and leading to the occurrence and development of inflammation, with systemic inflammation occurring in severe cases. Sepsis is a major cause of mortality in critically ill patients. In sepsis, the gastrointestinal tract is the first and most frequently involved target organ, which often leads to gastrointestinal dysfunction. HPA overexpression has been determined to accelerate sepsis progression and gastrointestinal dysfunction; thus, it was hypothesized that HPA may play an important role and may serve as an index for the diagnosis of gastrointestinal dysfunction in sepsis. HPA inhibitors may therefore become applicable as targeted drugs for the treatment of gastrointestinal dysfunction in patients with sepsis. The present review mainly discussed the role of HPA in gastrointestinal dysfunction of sepsis.

Targeting the "sweet spot" in septic shock - A perspective on the endothelial glycocalyx regulating proteins Heparanase-1 and -2

Sepsis is a life-threatening syndrome caused by a pathological host response to an infection that eventually, if uncontrolled, leads to septic shock and ultimately, death. In sepsis, a massive aggregation of pathogen-associated molecular patterns (PAMPs) and damage-associated molecular patterns (DAMPs) cause a cytokine storm. The endothelial glycocalyx (eGC) is a gel like layer on the luminal side of the endothelium that consists of proteoglycans, glycosaminoglycans (GAG) and plasma proteins. It is synthesized by endothelial cells and plays an active role in the regulation of inflammation, permeability, and coagulation. In sepsis, early and profound injury of the eGC is observed and circulating eGC components correlate directly with clinical severity and outcome. The activity of the heparan sulfate (HS) specific glucuronidase Heparanase-1 (Hpa-1) is elevated in sepsis, resulting in shedding of heparan sulfate (HS), a main GAG of the eGC. HS induces endothelial barrier breakdown and accelerates systemic inflammation. Lipopolysaccharide (LPS), a PAMP mainly found on the surface of gram-negative bacteria, activates TLR-4, which results in cytokine production and further activation of Hpa-1. Hpa-1 shed HS fragments act as DAMPs themselves, leading to a vicious cycle of inflammation and end-organ dysfunction such as septic cardiomyopathy and encephalopathy. Recently, Hpa-1's natural antagonist, Heparanase-2 (Hpa-2) has been identified. It has no intrinsic enzymatic activity but instead acts by reducing inflammation. Hpa-2 levels are reduced in septic mice and patients, leading to an acquired imbalance of Hpa-1 and Hpa-2 paving the road towards a therapeutic intervention. Recently, the synthetic antimicrobial peptide 19-2.5 was described as a promising therapy protecting the eGC by inhibition of Hpa-1 activity and HS shed fragments in animal studies. However, a recombinant Hpa-2 therapy does not exist to the present time. Therapeutic plasma exchange (TPE), a modality already tested in clinical practice, effectively removes injurious mediators, e.g., Hpa-1, while replacing depleted protective molecules, e.g., Hpa-2. In critically ill patients with septic shock, TPE restores the physiological Hpa-1/Hpa-2 ratio and attenuates eGC breakdown. TPE results in a significant improvement in hemodynamic instability including reduced vasopressor requirement. Although promising, further studies are needed to determine the therapeutic impact of TPE in septic shock.

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.

Syndecan-1 Shedding by Matrix Metalloproteinase-9 Signaling Regulates Alveolar Epithelial Tight Junction in Lipopolysaccharide-Induced Early Acute Lung Injury

INTRODUCTION

Alveolar epithelial tight junction damage and glycocalyx syndecan-1 (SDC-1) degrading are key factors to pulmonary edema of acute lung injury (ALI). Matrix metalloproteinase-9 (MMP-9) was involved in glycocalyx shedding, which was vital in SDC-1 degrading. This study aimed to investigate the effects of MMP-9-mediated SDC-1 shedding on tight junction in LPS-induced ALI.

METHODS

Mice were intratracheally atomized with 5 mg/kg LPS to stimulate different periods and LPS stimulation for 6 hours for further studies. A549 cells was stimulated for 6 hours by active MMP-9 protein to assess the effects of active MMP-9 protein on SDC-1 and tight junction. Afterward, the mice treated with MMP-9 shRNA or A549 cells were treated with MMP-9 siRNA before LPS stimulation for 6 hours to explore the effects on glycocalyx SDC-1 and tight junction. Moreover, the mice were treated with recombinant SDC-1 protein or A549 cells were over-expressed by pc-SDC-1 before LPS stimulation for 6 hours to explore the effects of SDC-1 on tight junction.

RESULTS

The mice persistent exposure to LPS showed that MMP-9 expression, glycocalyx SDC-1 shedding (SDC-1 decreased in alveolar epithelium and increased in the BALF), tight junction impairment, FITC-albumin infiltration, and other phenomena began to appear after 6 hours of LPS treatment in this study. The levels of SDC-1 and tight junction significantly decreased by active MMP-9 protein stimulation for 6 hours in the A549 cells. Therefore, LPS stimulation for six hours was selected for investigating the underlying effects of MMP-9-mediated SDC-1 shedding on the alveolar epithelial tight junction and pulmonary edema. Further vivo analysis showed that down regulation MMP-9 expression by MMP-9 shRNA significantly alleviated glycocalyx SDC-1 shedding (SDC-1 increased in alveolar epithelium and decreased in the BALF), tight junction (occludin and ZO-1) damage, and FITC-albumin infiltration in LPS-induced early ALI mice. The vitro results also showed that MMP-9 siRNA alleviated glycocalyx SDC-1 shedding (SDC-1 increased in cell culture medium and decreased in cell surface) and tight junction damage by downregulating MMP-9 expression in LPS-stimulated A549 cells. In addition, pretreatment with recombinant mouse SDC-1 protein significantly alleviated glycocalyx (SDC-1 increased in alveolar epithelium) and tight junction damage, and FITC-albumin infiltration in LPS-induced early ALI mice. Overexpression SDC-1 by pc-SDC-1 also significantly decreased tight junction damage in LPS-stimulated A549 cells.

CONCLUSION

Glycocalyx SDC-1 shedding mediated by MMP-9 significantly aggravated tight junction damage, which further increased the pulmonary edema.

Remifentanil attenuates sepsis-induced intestinal injury by inducing autophagy

Remifentanil (RFT), extensively used for general anesthesia, is a synthetic ultra-short-acting opioid used as an anti-inflammatory oxidant to alleviate a plethora of diseases. This study was designed to determine whether RFT would provide protective effects on sepsis-induced intestinal injury.The determination of cell viability and inflammation of LPS-treated IEC-6 cells influenced by RFT was conducted by Cell counting Kit-8 (CCK-8), RT-qPCR, and western blot, while the detection of LDH, diamine oxidase (DAO), and intestinal-type fatty acid binding proteins (I-FABP) was conducted for determining the intestinal cytotoxicity in these cells. The apoptosis of these cells was detected by TUNEL, with autophagy-related protein expression measured by western blot to confirm whether autophagy was activated. Finally, the aforementioned assays were conducted again after 3-Methyladenine (3-MA), an autophagy inhibitor, was used on these cells to investigate whether RFT exerted its effects on LPS-treated IEC-6 cells via modulation of autophagy.RFT alleviates LPS-induced IEC-6 cell inflammation, cytotoxicity and apoptosis, and autophagy-related proteins were expressed at higher levels when RFT was used on these cells. Nevertheless, further treatment of 3-MA weakened the restorative impacts of RFT on the inflammation, cytotoxicity and apoptosis of these cells.To conclude, this paper is the first to present evidence that RFT attenuates sepsis-induced intestinal injury by inducing autophagy, which will provide instructions for the future investigations into the use of RFT in treatment of intestinal injury.

Circular RNA CircHIPK3 Promotes Homeostasis of the Intestinal Epithelium by Reducing MicroRNA 29b Function

BACKGROUND & AIMS

Circular RNAs (circRNAs) are a class of endogenous noncoding RNAs that form covalently closed circles. Although circRNAs influence many biological processes, little is known about their role in intestinal epithelium homeostasis. We surveyed circRNAs required to maintain intestinal epithelial integrity and identified circular homeodomain-interacting protein kinase 3 (circHIPK3) as a major regulator of intestinal epithelial repair after acute injury.

METHODS

Intestinal mucosal tissues were collected from mice exposed to cecal ligation and puncture for 48 hours and patients with inflammatory bowel diseases and sepsis. We isolated primary enterocytes from the small intestine of mice and derived intestinal organoids. The levels of circHIPK3 were silenced in intestinal epithelial cells (IECs) by transfection with small interfering RNAs targeting the circularization junction of circHIPK3 or elevated using a plasmid vector that overexpressed circHIPK3. Intestinal epithelial repair was examined in an in vitro injury model by removing part of the monolayer. The association of circHIPK3 with microRNA 29b (miR-29b) was determined by biotinylated RNA pull-down assays.

RESULTS

Genome-wide profile analyses identified ∼300 circRNAs, including circHIPK3, differentially expressed in the intestinal mucosa of mice after cecal ligation and puncture relative to sham mice. Intestinal mucosa from patients with inflammatory bowel diseases and sepsis had reduced levels of circHIPK3. Increasing the levels of circHIPK3 enhanced intestinal epithelium repair after wounding, whereas circHIPK3 silencing repressed epithelial recovery. CircHIPK3 silencing also inhibited growth of IECs and intestinal organoids, and circHIPK3 overexpression promoted intestinal epithelium renewal in mice. Mechanistic studies revealed that circHIPK3 directly bound to miR-29b and inhibited miR-29 activity, thus increasing expression of Rac1, Cdc42, and cyclin B1 in IECs after wounding.

CONCLUSIONS

In studies of mice, IECs, and human tissues, our results indicate that circHIPK3 improves repair of the intestinal epithelium at least in part by reducing miR-29b availability.

Gadolinium chloride pre-treatment reduces the inflammatory response and preserves intestinal barrier function in a rat model of sepsis

The inflammatory response is closely associated with sepsis occurrence and progression. Damage to the function of the intestinal mucosal barrier is considered to be the ῾initiation factor᾿ for the development of multiple organ dysfunction syndrome, which is the most severe progression of sepsis. The aim of the present study was to investigate whether gadolinium chloride (GdCl₃) could alleviate the systemic inflammatory response and protect the function of the intestinal mucosal barrier in a rat model of sepsis. The mechanism underlying this protective effect was also explored. Sprague-Dawley rats were divided into four groups: Sham, sham + GdCl₃, cecal ligation and puncture (CLP; a model of sepsis) and CLP + GdCl₃. In each group, blood was collected from the abdominal aorta, and intestinal tissue was collected after 6, 12 and 24 h of successful modeling. Levels of tumor necrosis factor-α, interleukin (IL)-6 and IL-1β were determined using ELISA. Western blot analysis was used to determine levels of occludin, tight junction protein ZO-1 (ZO-1), myosin light chain kinase 3 (MLCK), NF-κB and caspase-3 in intestinal tissues. Hematoxylin-eosin staining was used to observe the degree of damage to intestinal tissue. The results indicated that in CLP sepsis model rats treated with GdCl₃, the release of systemic and intestinal pro-inflammatory factors was reduced and tissue damage was alleviated when compared with untreated CLP rats. Additionally, the expression of occludin and ZO-1 was increased, while that of NF-κB, MLCK, and caspase-3 was reduced in the CLP + GdCl₃ rats compared with the CLP rats. GdCl₃ may alleviate systemic and intestinal inflammatory responses and reduce the expression of MLCK through inhibition of the activation of NF-kB. The results of the present study also indicated that GdCl₃ promoted the expression of occludin and ZO-1. GdCl₃ was also demonstrated to reduce cell apoptosis through the inhibition of caspase-3 expression.

Unfractionated Heparin Improves the Intestinal Microcirculation in a Canine Septic Shock Model

Background

Alterations of microcirculation are associated with organ hypoperfusion and high mortality in septic shock. This study is aimed at investigating the effects of unfractionated heparin (UFH) on intestinal microcirculatory perfusion and systemic circulation in a septic shock model.

Methods

Twenty-four beagle dogs were randomly allocated into four groups: (a) sham group: healthy controls, (b) shock group: septic shock induced by Escherichia coli, (c) basic therapy group: septic shock animals treated with antibiotics and 10 ml/kg/h saline, and (d) heparin group: septic shock animals treated with basic therapy plus UFH. Hemodynamic variables were measured within 24 h after E. coli administration. The intestinal microcirculation was simultaneously investigated with a sidestream dark-field imaging technique. Additionally, the function of vital organs was evaluated at 12 h postadministration (T12).

Results

E. coli induced a progressive septic shock in which the mean arterial pressure (MAP) decreased and lactate levels sharply increased, accompanied by deteriorated microvessel perfusion. While basic therapy partially improved the microvascular flow index and the perfused microvessel density in the jejunal villi, UFH significantly restored major microcirculation variables at T12. Physiological variables, including MAP, urine output, and lactate levels, were improved by UFH, whereas some hemodynamic indices were not affected by UFH. With respect to organ function, UFH increased the platelet count and decreased the creatinine level.

Conclusions

UFH improves microcirculatory perfusion of the small intestine independently of the changes in systemic hemodynamic variables in a canine model of septic shock, thereby improving coagulation and renal function.

Helicobacter pylori-Induced Heparanase Promotes H. pylori Colonization and Gastritis

Chronic gastritis caused by Helicobacter pylori (H. pylori) infection has been widely recognized as the most important risk factor for gastric cancer. Analysis of the interaction between the key participants in gastric mucosal immunity and H. pylori infection is expected to provide important insights for the treatment of chronic gastritis and the prevention of gastric cancer. Heparanase is an endoglycosidase that degrades heparan sulfate, resulting in remodeling of the extracellular matrix thereby facilitating the extravasation and migration of immune cells towards sites of inflammation. Heparanase also releases heparan sulfate-bound cytokines and chemokines that further promote directed motility and recruitment of immune cells. Heparanase is highly expressed in a variety of inflammatory conditions and diseases, but its role in chronic gastritis has not been sufficiently explored. In this study, we report that H. pylori infection promotes up-regulation of heparanase in gastritis, which in turn facilitates the colonization of H. pylori in the gastric mucosa, thereby aggravating gastritis. By sustaining continuous activation, polarization and recruitment of macrophages that supply pro-inflammatory and pro-tumorigenic cytokines (i.e., IL-1, IL-6, IL-1β, TNF-α, MIP-2, iNOS), heparanase participates in the generation of a vicious circle, driven by enhanced NFκB and p38-MAPK signaling, that supports the development and progression of gastric cancer. These results suggest that inhibition of heparanase may block this self-sustaining cycle, and thereby reduce the risk of gastritis and gastric cancer.

Endothelial glycocalyx in traumatic brain injury associated coagulopathy: potential mechanisms and impact

Traumatic brain injury (TBI) remains one of the leading causes of death and disability worldwide; more than 10 million people are hospitalized for TBI every year around the globe. While the primary injury remains unavoidable and not accessible to treatment, the secondary injury which includes oxidative stress, inflammation, excitotoxicity, but also complicating coagulation abnormalities, is potentially avoidable and profoundly affects the therapeutic process and prognosis of TBI patients. The endothelial glycocalyx, the first line of defense against endothelial injury, plays a vital role in maintaining the delicate balance between blood coagulation and anticoagulation. However, this component is highly vulnerable to damage and also difficult to examine. Recent advances in analytical techniques have enabled biochemical, visual, and computational investigation of this vascular component. In this review, we summarize the current knowledge on (i) structure and function of the endothelial glycocalyx, (ii) its potential role in the development of TBI associated coagulopathy, and (iii) the options available at present for detecting and protecting the endothelial glycocalyx.

Heparanase expression and activity are increased in platelets during clinical sepsis

BACKGROUND

Heparanase (HPSE) is the only known mammalian enzyme that can degrade heparan sulfate. Heparan sulfate proteoglycans are essential components of the glycocalyx, and maintain physiological barriers between the blood and endothelial cells. HPSE increases during sepsis, which contributes to injurious glyocalyx degradation, loss of endothelial barrier function, and mortality.

OBJECTIVES

As platelets are one of the most abundant cellular sources of HPSE, we sought to determine whether HPSE expression and activity increases in human platelets during clinical sepsis. We also examined associations between platelet HPSE expression and clinical outcomes.

PATIENTS/METHODS

Expression and activity of HPSE was determined in platelets isolated from septic patients (n = 59) and, for comparison, sex-matched healthy donors (n = 46) using complementary transcriptomic, proteomic, and functional enzymatic assays. Septic patients were followed for the primary outcome of mortality, and clinical data were captured prospectively for septic patients.

RESULTS

The mRNA expression of HPSE was significantly increased in platelets isolated from septic patients. Ribosomal footprint profiling, followed by [S35] methionine labeling assays, demonstrated that HPSE mRNA translation and HPSE protein synthesis were significantly upregulated in platelets during sepsis. While both the pro- and active forms of HPSE protein increased in platelets during sepsis, only the active form of HPSE protein significantly correlated with sepsis-associated mortality. Consistent with transcriptomic and proteomic upregulation, HPSE enzymatic activity was also increased in platelets during sepsis.

CONCLUSIONS

During clinical sepsis HPSE, translation, and enzymatic activity are increased in platelets. Increased expression of the active form of HPSE protein is associated with sepsis-associated mortality.

EZH2 inhibitor GSK343 inhibits sepsis-induced intestinal disorders

Enhancer of zeste homolog 2 (EZH2) is positively associated with poor clinical outcomes in a number of aggressive tumors. Recent studies have demonstrated that inhibition of EZH2 also suppressed the inflammatory response during sepsis. The present study aimed to investigate whether an inhibitor of EZH2, GSK343, could protect the intestine against sepsis-induced injury in vivo. Mice underwent cecal ligation and perforation (CLP) to induce sepsis and were assigned into three groups: Sham, CLP and CLP + GSK343. For GSK343 treatment, the septic mice were intravenously injected with GSK343 at 6 h post-CLP. The results indicated that EZH2 was highly expressed while tight junction (TJ) proteins ZO-1, occludin and claudin-1 expression was reduced in the intestinal tissue of mice subjected to CLP compared with the sham group. CLP operation also caused intestinal pathological injury and the production of inflammatory cytokines including TNF-α, IL-1β and IL-6 in both serum and intestinal tissues. Meanwhile, CLP induced cell apoptosis of intestinal tissue based on the increased number of apoptotic cells, reduced expression of Bcl-2 and higher expression of caspase-3 and Bax. However, the presence of GSK343 partially rescued intestinal pathological injury, reduced the level of inflammatory cytokines, repressed cell apoptosis and promoted TJ protein expression. Finally, the decreased number of Paneth cells caused by CLP operation was reversed by GSK343 treatment. In conclusion, the results of the present study demonstrated that GSK343 could protect the intestine against sepsis-induced injury in vivo. Inhibition of EZH2 may provide a therapeutic approach for intestinal dysfunction during sepsis.

Alveolar epithelial glycocalyx shedding aggravates the epithelial barrier and disrupts epithelial tight junctions in acute respiratory distress syndrome

The main pathophysiological mechanism of acute respiratory distress syndrome (ARDS) invovles the increase in alveolar barrier permeability that is primarily caused by epithelial glycocalyx and tight junction (TJ) protein destruction. This study was performed to explore the effects of the alveolar epithelial glycocalyx on the epithelial barrier, specifically on TJ proteins, in ARDS. We used C57BL/6 mice and human lung epithelial cell models of lipopolysaccharide (LPS)-induced ARDS. Changes in alveolar permeability were evaluated via pulmonary histopathology analysis and by measuring the wet/dry weight ratio of the lungs. Degradation of heparan sulfate (HS), an important component of the epithelial glycocalyx, and alterations in levels of the epithelial TJ proteins (occludin, zonula occludens 1, and claudin 4) were assessed via ELISA, immunofluorescence analysis, and western blotting analysis. Real-time quantitative polymerase chain reaction was used to detect the mRNA of the TJ protein. Changes in glycocalyx and TJ ultrastructures in alveolar epithelial cells were evaluated through electron microscopy. In vivo and in vitro, LPS increased the alveolar permeability and led to HS degradation and TJ damage. After LPS stimulation, the expression of the HS-degrading enzyme heparanase (HPA) in the alveolar epithelial cells was increased. The HPA inhibitor N-desulfated/re-N-acetylated heparin alleviated LPS-induced HS degradation and reduced TJ damage. In vitro, recombinant HPA reduced the expression of the TJ protein zonula occludens-1 (ZO-1) and inhibited its mRNA expression in the alveolar epithelial cells. Taken together, our results demonstrate that shedding of the alveolar epithelial glycocalyx aggravates the epithelial barrier and damages epithelial TJ proteins in ARDS, with the underlying mechanism involving the effect of HPA on ZO-1.

Targeting Endothelial Dysfunction in Acute Critical Illness to Reduce Organ Failure

During hyperinflammatory conditions that can occur in acute critical illness, such as shock or hypoperfusion, inflammatory mediators activate the endothelium, fueling a proinflammatory host-response as well as procoagulant processes. These changes result in shedding of the glycocalyx, endothelial hyperpermeability, edema formation, and lead to disturbed microcirculatory perfusion and organ failure. Different fluid strategies that are used in shock may have differential effects on endothelial integrity. Collectively, low protein content fluids seem to have negative effects on the endothelial glycocalyx, aggravating endothelial hyperpermeability, whereas fluids containing albumin or plasma proteins may be superior to normal saline in protecting the glycocalyx and endothelial barrier function. Targeting the endothelium may be a therapeutic strategy to limit organ failure, which hitherto has not received much attention. Treatment targets aimed at restoring the endothelium should focus on maintaining glycocalyx function and/or targeting coagulation pathways or specific endothelial receptors. Potential treatments could be supplementing glycocalyx constituents or inhibiting glycocalyx breakdown. In this review, we summarize mechanisms of endothelial dysfunction during acute critical illness, such as the systemic inflammatory response, shedding of the glycocalyx, endothelial activation, and activation of coagulation. In addition, this review focuses on the effects of different fluid strategies on endothelial permeability. Also, potential mechanisms for treatment options to reduce endothelial hyperpermeability with ensuing organ failure are evaluated. Future research is needed to elucidate these pathways and to translate these data to the first human safety and feasibility trials.

Heparanase: Cloning, Function and Regulation

In 2019, we mark the 20th anniversary of the cloning of the human heparanase gene. Heparanase remains the only known enzyme to cleave heparan sulfate, which is an abundant component of the extracellular matrix. Thus, elucidating the mechanisms underlying heparanase expression and activity is critical to understanding its role in healthy and pathological settings. This chapter provides a historical account of the race to clone the human heparanase gene, describes the intracellular and extracellular function of the enzyme, and explores the various mechanisms regulating heparanase expression and activity at the gene, transcript, and protein level.

Heparanase in Acute Kidney Injury

Recent years have brought about fledgling realization of the role played by heparanase in the pathogenesis of diverse diseases including kidney diseases and, specifically, acute kidney injury. Human heparanase-1 is critically and uniquely engaged in cleavage of heparan sulfate, an integral part of glycocalyx and extracellular matrix where it harbors distinct growth factors, cytokines, and other biologically active molecules. The enzyme is induced and activated in acute kidney injury regardless of its causes, ischemic, nephrotoxic, septic or transplantation-related. This event unleashes a host of sequelae characteristic of the pathogenesis of acute kidney injury, such as induction and reinforcement of innate immune responses, predisposition to thrombosis, activation of monocytes/macrophages and remodeling of the extracellular matrix, thus setting up the stage for future fibrotic complications and development of chronic kidney disease. We briefly discuss the emerging therapeutic strategies of inhibiting heparanase, as well as the diagnostic value of detecting products of heparanase activity for prognostication and treatment.

Both UFH and NAH alleviate shedding of endothelial glycocalyx and coagulopathy in LPS-induced sepsis

Sepsis commonly progresses to disseminated intravascular coagulation and induces the activation of heparanase (HPA) and the shedding of endothelial glycocalyx constituents, including syndecan-1 (SDC-1) and heparan sulphate (HS). However, the degradation of glycocalyx and its association with coagulation disorders remains undetermined. The present study aimed to evaluate the effect of unfractionated heparin (UFH) and N-acetylheparin (NAH), which is a non-anticoagulant heparin derivative, on endothelial glycocalyx and coagulation function in a lipopolysaccharide (LPS)-induced sepsis rat model, and to compare the differences observed in coagulation function between UFH and NAH. Experimental rats were randomly assigned to four groups: Control; LPS; UFH + LPS; and NAH + LPS. Rats were administered UFH or NAH and subsequently, ~1 min later, administered LPS (10 mg/kg; intravenous). The blood and lung tissues of rats were collected 0.5, 2 and 6 h after LPS injection, and were used for subsequent analysis. The results demonstrated that HPA activity and SDC-1 and HS levels increased, and this increase was associated with inflammatory cytokines and coagulation/fibrinolysis markers in the sepsis rat model. Histopathological examination was performed, and the lung injury score and lung wet/dry ratio indicated that UFH and NAH also significantly improved lung tissue injury. The results of the ELISA analysis demonstrated that UFH and NAH treatment: i) significantly decreased the levels of inflammatory cytokines including tumor necrosis factor-α and interleukin-6; ii) inhibited HPA activity and protected the integrity of the glycocalyx, which was identified by decreased HS and SDC-1 levels; and iii) decreased the levels of prothrombin fragment 1+2, thrombin-antithrombin complex, and plasminogen activator inhibitor-1 and increased the levels of fibrinogen and antithrombin-III. Preconditioning with UFH decreased the plasma activated partial thromboplastin time. These results indicated that UFH and NAH may alleviate sepsis-induced coagulopathy, and this effect may have been due to an inhibition of HPA activity and decrease in the shedding of the endothelial glycocalyx.

Peripheral neuropathy following bortezomib therapy in multiple myeloma patients: association with cumulative dose, heparanase, and TNF-α

Multiple myeloma (MM) is a plasma cell neoplasm which constitutes about 10% of all hematologic malignancies. Despite bortezomib is a promising new generation of drugs for MM, its clinical use is limited by peripheral neurotoxicity in the vast majority of patients, which can be severe and require a reduction of dose or even treatment withdrawal. Tumor necrosis factor-α (TNF-α), as the most important inflammatory factor, could induce the inflammatory response and expression of heparanase (HPSE), which may play a crucial role in peripheral neuropathy after chemotherapy. However, the role of TNF-α in bortezomib-induced peripheral neuropathy (BIPN) has not been reported. In this study, treatment-emergent neuropathy was assessed by total neuropathy score and electrophysiological examination. The expression level of TNF-α and HPSE were evaluated by enzyme-linked immunosorbent assay. The effects of anti-TNF-α on the evolution of neuropathy were tested in rat models of neurotoxicity. The results indicated that with the augment of cumulative dose of bortezomib, the incidence of neuropathy was increased. Moreover, bortezomib administration induced the expression of TNF-α. With the increased expression of TNF-α, neuropathy was exacerbated. TNF-α-induced expression of HSPE was secondary to the development of neuropathy. Co-administration of anti-TNF-α in bortezomib therapy has a potential neuroprotective effect on BIPN in rats. TNF-α participates in the pathogenesis of BIPN, which represents an attractive target for future therapeutic intervention.

Modulation of Intestinal Epithelial Glycocalyx Development by Human Milk Oligosaccharides and Non-Digestible Carbohydrates

SCOPE

The epithelial glycocalyx development is of great importance for microbial colonization. Human milk oligosaccharides (hMOs) and non-digestible carbohydrates (NDCs) may modulate glycocalyx development.

METHODS AND RESULTS

The effects of hMOs and NDCs on human gut epithelial cells (Caco2) are investigated by quantifying thickness and area coverage of adsorbed albumin, heparan sulfate (HS), and hyaluronic acid (HA) in the glycocalyx. Effects of hMOs (2'-FL and 3-FL) and NDCs [inulins with degrees of polymerization (DP) (DP3-DP10, DP10-DP60, DP30-DP60) and pectins with degrees of methylation (DM) (DM7, DM55, DM69)] are tested using immunofluorescence staining at 1 and 5 days stimulation. HMOs show a significant enhancing effect on glycocalyx development but effects are structure-dependent. 3-FL induces a stronger albumin adsorption and increases HS and HA stronger than 2'-FL. The DP3-DP10, DP30-60 inulins also increase glycocalyx development in a structure-dependent manner as DP3-DP10 selectively increases HS, while DP30-DP60 specifically increases HA. Pectins have less effects, and only increase albumin adsorption.

CONCLUSION

Here, it is shown that 2'-FL and 3-FL and inulins stimulate glycocalyx development in a structure-dependent fashion. This may contribute to formulation of effective hMO and NDC formulations in infant formulas to support microbial colonization and gut barrier function.

Syndecan-1 Shedding Inhibition to Protect Against Ischemic Acute Kidney Injury Through HGF Target Signaling Pathway

BACKGROUND

The hepatocyte growth factor (HGF) target pathway plays pivotal renoprotective roles after acute kidney injury. Syndecan-1 (SDC-1) serves as the coreceptor for HGF. Shedding of SDC-1 is involved in various pathological processes. Thus, we hypothesized that ischemia/reperfusion injury induced SDC-1 shedding, and inhibiting SDC-1 shedding would protect against kidney injury by potentiating activation of the HGF receptor mesenchymal epithelial transition factor (c-Met).

METHODS

Expression of SDC-1 and its sheddases were observed in kidneys of sham and ischemia/reperfusion (I/R) mice. To inhibit SDC-1 shedding, mice were injected with the sheddase inhibitor GM6001 before I/R surgery, and then, renal inflammation, tubular apoptosis, and activation of the c-Met/AKT/glycogen synthase kinase-3β (GSK-3β) pathway were analyzed. In vitro, human proximal tubular cell lines were pretreated with GM6001 under hypoxia/reperfusion conditions. The apoptosis and viability of cells and expression of c-Met/AKT/GSK-3β pathway components were evaluated. The relationship was further confirmed by treatment with SU11274, a specific inhibitor of phospho-c-Met.

RESULTS

Shedding of SDC-1 was induced after ischemia/reperfusion injury both in vivo and in vitro. GM6001 pretreatment suppressed SDC-1 shedding, alleviated renal inflammation and tubular apoptosis, and upregulated phosphorylation of the c-Met/AKT/GSK-3β pathway. In vitro, pretreatment with GM6001 also decreased hypoxia/reperfusion-induced cell apoptosis and promoted activation of the c-Met pathway. In addition, the cytoprotective role of GM6001 was attenuated by suppressing c-Met phosphorylation with SU11274.

CONCLUSIONS

Our findings suggest that inhibiting I/R-induced SDC-1 shedding protected against ischemic acute kidney injury by potentiating the c-Met/AKT/GSK-3β pathway.

Unfractionated heparin ameliorates pulmonary microvascular endothelial barrier dysfunction via microtubule stabilization in acute lung injury

Background

Endothelial barrier dysfunction is central to the pathogenesis of sepsis-associated acute lung injury (ALI). Microtubule (MT) dynamics in vascular endothelium are crucial for the regulation of endothelial barrier function. Unfractionated heparin (UFH) possesses various biological activities, such as anti-inflammatory activity and endothelial barrier protection during sepsis.

Methods

Here, we investigated the effects and underlying mechanisms of UFH on lipopolysaccharide (LPS)-induced endothelial barrier dysfunction. C57BL/6 J mice were randomized into vehicle, UFH, LPS and LPS + UFH groups. Intraperitoneal injection of 30 mg/kg LPS was used to induce sepsis. Mice in the LPS + UFH group received intravenous UFH 0.5 h prior to LPS injection. Human pulmonary microvascular endothelial cells (HPMECs) were cultured for analyzing the effects of UFH on LPS-induced and nocodazole-induced hyperpermeability, F-actin remodeling, and LPS-induced p38 MAPK activation.

Results

UFH pretreatment significantly attenuated LPS-induced pulmonary histopathological changes, and increased the lung W/D ratio and Evans blue accumulation in vivo. Both in vivo and in vitro studies showed that UFH pretreatment blocked the LPS-induced increase in guanine nucleotide exchange factor (GEF-H1) expression and myosin phosphatase target subunit 1 (MYPT1) phosphorylation, and microtubule (MT) disassembly in LPS-induced ALI mouse model and human pulmonary microvascular endothelial cells (HPMECs). These results suggested that UFH ameliorated LPS-induced endothelial barrier dysfunction by inhibiting MT disassembly and GEF-H1 expression. In addition, UFH attenuated LPS-induced hyperpermeability of HPMECs and F-actin remodeling. In vitro, UFH pretreatment inhibited LPS-induced increase in monomeric tubulin expression and decrease in tubulin polymerization and acetylation. Meanwhile, UFH ameliorates nocodazole-induced MTs disassembly and endothelial barrier dysfunction.Additionally, UFH decreased p38 phosphorylation and activation, which was similar to the effect of the p38 MAPK inhibitor, SB203580.

Conclusions

UFH exert its protective effects on pulmonary microvascular endothelial barrier dysfunction via microtubule stabilization and is associated with the p38 MAPK pathway.

Berberine alleviates endothelial glycocalyx degradation and promotes glycocalyx restoration in LPS-induced ARDS

In the pathogenesis of acute respiratory distress syndrome (ARDS), an increase in vascular endothelial permeability may trigger pulmonary edema and ultimately lead to respiratory failure. Endothelial glycocalyx damage is an important factor that causes an increase in vascular endothelial permeability. Berberine (BBR) is an isoquinoline alkaloid extracted from Coptis chinensis, a plant used in traditional Chinese medicine that exerts multiple pharmacological effects. In this study, pretreatment with BBR inhibited the increase in vascular endothelial permeability in mice with lipopolysaccharide (LPS)-induced ARDS. BBR pretreatment inhibited the shedding of syndecan-1 (SDC-1) and heparan sulfate (HS), which are important components of the endothelial glycocalyx that lessen endothelial glycocalyx damage. BBR further significantly inhibited increases in important endothelial glycocalyx damage factors, including reactive oxygen species (ROS), heparanase (HPA), and matrix metalloproteinase 9 (MMP9) in LPS-induced ARDS mice and in LPS-stimulated human umbilical vein endothelial cells. BBR pretreatment also decreased the production of pro-inflammatory cytokines TNF-α, IL-1β, IL-6, and inhibited NF-κB signaling pathway activation in LPS-induced ARDS. In addition, BBR promoted the recovery of SDC-1 and HS content in injured endothelial glycocalyx after LPS treatment and accelerated its restoration. This is the first report of BBR maintaining the integrity of endothelial glycocalyx. These results provide a new theoretical basis for the use of BBR in the treatment of ARDS and other diseases related to endothelial glycocalyx damage.

The Role of Heparan Sulfate in Inflammation, and the Development of Biomimetics as Anti-Inflammatory Strategies

Key events that occur during inflammation include the recruitment, adhesion, and transmigration of leukocytes from the circulation to the site of inflammation. These events are modulated by chemokines, integrins, and selectins and the interaction of these molecules with glycosaminoglycans, predominantly heparan sulfate (HS). The development of HS/heparin mimetics that interfere or inhibit the interactions that occur between glycosaminoglycans and modulators of inflammation holds great potential for use as anti-inflammatory therapeutics. This review will detail the role of HS in the events that occur during inflammation, their interaction and modulation of inflammatory mediators, and the current advances in the development of HS/heparin mimetics as anti-inflammatory biotherapeutics.