Cytokine gene expression and production by human LPS-stimulated mononuclear cells are inhibited by sulfated heparin-like semi-synthetic derivatives

Regioselective sulfated chitosan produces a biocompatible and antibacterial wound dressing with low inflammatory response

The aim of current study is to tailor chitosan derivate which is water-soluble while presents original biological features of chitosan. For this purpose, the 6-O chitosan sulfate (CS) with naked amine groups was synthesized via regioselective modification of chitosan (C) during which both crosslinking capacity and antibacterial properties of the C were remained intact. This was achieved by sulfation the C under controlled acidic conditions using chlorosulfonic acid/sulfuric acid mixture. Subsequently, a chemically crosslinked hydrogel of the CS was used as a wound dressing substrate. The modified sulfate groups retained the biocompatibility of C and showed antibacterial effects against gram-positive and gram-negative bacteria. In addition, the presence of sulfate groups in the CS chemical structure improved its anticoagulant activity compared to the unmodified C. Both in vitro and in vivo enzyme-linked immunosorbent assay (ELISA) measurements showed that CS had a higher potential to bind and scavenger anti-inflammatory cytokines, including IL-6 and transforming growth factor-β (TGF-β), both of which play critical roles in the early stage of the wound healing process. After treatment of full-thickness wounds with CS hydrogels, the macrophage cells (c.a. 6 × 10⁴ cells) expressed significantly more M2 phenotype markers compared to the C group (4.2 × 10⁴ cells). Furthermore, the CS hydrogel induced better re-epithelialization and vascularization of full-thickness wounds in mice compared to the C hydrogel during 30 days.

Low molecular weight heparin reduces acute phase response and multiple organ dysfunction following Ovine experimental endotoxemia model

Endotoxemia is one of the most common inflammatory situations leading to death of ruminants. Owing to the importance of this condition, several therapeutic regimens have been proposed, evaluated and implemented to treat endotoxemia. It has recently been suggested that low molecular weight heparin may be effective in treating endotoxemia. Thus, the present experimental study was conducted to evaluate the acute phase response and multiple organ dysfunction following the treatment of the Ovine experimental endotoxemia model employing this compound. In this regard, 20 clinically healthy 1-year old Iranian fat-tailed ewes were randomly divided into 4 equal groups, comprising LMWH 50, LMWH 100, Ctrl+, and Ctrl-. Lipopolysaccharide from Escherichia coli serotype O55:B5 at 0.4 μg/kg was intravenously administered to the ewes. Low molecular weight heparin (at 50 and 100 IU/kg) was administrated to LMWH 50 and LMWH 100 groups, respectively. Positive control (Ctrl+) received lipopolysaccharide and treated only by intravenous fluid without any drugs, and negative control (Ctrl-) only received intravenous fluids without lipopolysaccharide or any drugs. All the ewes were clinically evaluated before and 1.5, 3, 4.5, 6 and 24 h after lipopolysaccharide injection, and blood samplings were also performed at those hours. Serum concentrations of serum amyloid A, tumor necrosis factor-alpha, superoxide dismutase, glutathione peroxidase, creatine kinase-MB, homocysteine, total bilirubin, aspartate aminotransferase, and creatinine were measured. Serum concentrations of acute phase proteins, inflammatory cytokines, oxidative stress, cardiovascular, hepatic and renal biomarkers, and clinical parameters were significantly increased following the induction of endotoxemia in the groups receiving lipopolysaccharide. Significantly lower concentration of these markers was observed at 4.5 and 6 h after lipopolysaccharide administration in the sheep treated with LMWH compared to the Ctrl + group. In conclusion, low molecular weight heparin could act as an anti-inflammatory drug by decreasing cytokines and acute phase proteins, modulating oxidative stress biomarkers, and by reducing multiple organ dysfunction following the induction of endotoxemia by Escherichia coli serotype O55:B5 in Iranian fat-tailed sheep in a dose-dependent manner. Furthermore, the anti-inflammatory effects of low molecular weight heparin at 100 IU/kg were significantly higher than 50 IU/kg in the treatment of endotoxemic sheep.

Insights of efferocytosis in normal and pathological pregnancy

Efferocytosis, which is known as the phagocytic clearance of dying cells by professional as well as non-professional phagocytes, including a great number of intracellular/extracellular factors and signals, is interrelated with the immune system, contributing to local and systemic homeostasis, especially in tissues with high constitutive rates of apoptosis. Accumulating studies have indicated that immune dysregulation is associated with the pathogenesis of the female reproductive system, which causes preeclampsia (PE), recurrent spontaneous abortion (RSA), ruptured ectopic pregnancy, and so on. And some studies have revealed the pleiotropic and essential role of efferocytosis in these obstetrical disorders. More specifically, the occurrence and development of these diseases were in connection with some efferocytosis-related factors and signals, such as C1q, MBL, and IL-33/ST2. In this review, we systematically review the diverse impacts of efferocytosis in immune system and discuss its relevance to normal and pathological pregnancy. These findings may instruct future basic researches as well as clinical applications of efferocytosis-related factors and signals as latent predictors or therapeutic targets on the obstetrical disorders.

Effects of low molecular weight heparin on the polarization and cytokine profile of macrophages and T helper cells in vitro

Low molecular weight heparin (LMWH) is widely used in recurrent miscarriage treatment. The anti-coagulant effects are established, while immunological effects are not fully known. Our aim was to assess LMWH effects on activation and polarization of central regulatory immune cells from healthy women, and on placenta tissues from women undergoing elective abortions. Isolated blood monocytes and T helper (Th) cells under different activation and polarizing conditions were cultured with or without LMWH. Flow cytometry showed that LMWH exposure induced increased expression of HLA-DR and CD206 in macrophages. This phenotype was associated with increased secretion of Th17-associated CCL20, and decreased secretion of CCL2 (M2-associated) and CCL22 (Th2), as measured by multiplex bead array. In accordance, LMWH exposure to Th cells reduced the proportion of CD25highFoxp3+ regulatory T-cells, intensified IFN-γ secretion and showed a tendency to increase the lymphoblast proportions. Collectively, a mainly pro-inflammatory effect was noted on two essential tolerance-promoting cells. Although the biological significancies of these in vitro findings are uncertain and need to be confirmed in vivo, they suggest the possibility that immunological effects of LMWH may be beneficial mainly at an earlier gestational age to provide an appropriate implantation process in women with recurrent miscarriage.

Sulfated hyaluronan attenuates inflammatory signaling pathways in macrophages involving induction of antioxidants

It is well recognized that high molecular weight hyaluronan (H-HA) exerts potent anti-inflammatory effects while its fragmentation into low molecular weight HA (L-HA) is discussed to promote inflammation. Chemical modification of HA with sulfate groups has been shown to foster its anti-inflammatory activity which seems to be maintained in sulfated low molecular weight HA derivatives (sL-HA). However, the molecular mechanisms by which sL-HA produces its anti-inflammatory activity are not understood. In this study, we used global quantitative proteomics combined with targeted analysis of key proteins to characterize the effect of sL-HA on fully differentiated human inflammatory macrophages (iMФ). Culture of iMФ with sL-HA did not affect cell viability but resulted in a reduced pro-inflammatory cytokine response of iMФ after activation indicating a profound counter-regulation of their initial inflammatory phenotype. Rapid internalization of sL-HA involving CD44 and scavenger receptors was observed. Furthermore, an upregulation of the antioxidants SOD2 and SOD3 was found while no oxidative stress was induced. Consequently, activity of transcription factors for inflammatory gene expression was downregulated in iMФ with sL-HA after activation whereas anti-inflammatory proteins were induced. This study proves anti-inflammatory properties of sL-HA and provides information on its regulatory mode of action on iMФ.

Hyperglycemia, tumorigenesis, and chronic inflammation

Hyperglycemia is the most prominent sign that characterizes diabetes. Hyperglycemia favors malignant cell growth by providing energy to cancer cells. Clinical studies also showed an increased risk of diabetes being associated with different types of cancers. In addition, poorly regulated glucose metabolism in diabetic patients is often found with increased levels of chronic inflammatory markers, e.g., interleukin (IL)-1β, IL-6, and tumor necrosis factor (TNF)-α, and emerging evidence has highlighted activation of the immune response in the progression and development of cancer cells. Therefore, uncontrolled proinflammatory responses could conceivably create a chronic inflammatory state, promoting a tumor-favorable microenvironment and potentially triggering immune overactivation and cancer growth. To further understand how hyperglycemia contributes to immune overactivation, the tumor microenvironment and the development of chronic inflammation-associated tumors may provide insights into tumor biology and immunology. This paper provides a brief introduction to hyperglycemia-associated diseases, followed by a comprehensive overview of the current findings of regulatory molecular mechanisms of glycosylation on proteoglycans in the extracellular matrix under hyperglycemic conditions. Then, the authors discuss the role of hyperglycemia in tumorigenesis (particularly in prostate, liver, colorectal, and pancreatic cancers), as well as the contribution of hyperglycemia to chronic inflammation. The authors end with a brief discussion on the future perspectives of hyperglycemia/tumorigenesis and potential applications of alternative/effective therapeutic strategies for hyperglycemia-associated cancers.

Stimulation of RAW264.7 macrophages by sulfated Escherichia coli K5 capsular polysaccharide in vitro

The aim of the present study was to explore the immunomodulatory effects of sulfated K5 polysaccharide derivatives on RAW264.7 macro-phage cells, and to further elucidate the structure‑activity relationship. In the present study, chemically sulfated polysaccharides were derived from Escherichia coli K5 capsular polysaccharide (K5PS), and molecular weight determination, sugar analysis, and other physical and chemical characterizations were performed on the derived polysaccharides. Enzyme‑linked immunosorbent assay and reverse transcription‑polymerase chain reaction analyses demonstrated that K5‑OS2 stimulated murine RAW264.7 macrophage cells to release TNF‑α and IL‑1β proinflammatory cytokines. K5‑OS2 also induced the expression of inducible nitric oxide synthase iNOS, which is responsible for the production of nitric oxide. In addition, K5‑OS2 markedly induced macrophage‑mediated cytotoxicity against cancer cells and promoted the phagocytic activity of the RAW264.7 cells. Therefore, K5‑OS2 activated macrophages and acted as a potent immunomodulator. Observations of the present study also indicated that sulfation modification enhanced the immune‑enhancing activity of K5PS, and that the high sulfation in the O‑position of K5PS may be required for the immunomodulatory activities of the Escherichia coli K5 capsular polysaccharide.

Therapeutic Potential of Anti-Angiogenic Multitarget N,O-Sulfated E. Coli K5 Polysaccharide in Diabetic Retinopathy

Vascular endothelial growth factor (VEGF) blockers have been developed for the treatment of proliferative diabetic retinopathy (PDR), the leading cause of visual impairments in the working-age population in the Western world. However, limitations to anti-VEGF therapies may exist because of the local production of other proangiogenic factors that may cause resistance to anti-VEGF interventions. Thus, novel therapeutic approaches targeting additional pathways are required. Here, we identified a sulfated derivative of the Escherichia coli polysaccharide K5 [K5-N,OS(H)] as a multitarget molecule highly effective in inhibiting VEGF-driven angiogenic responses in different in vitro, ex vivo, and in vivo assays, including a murine model of oxygen-induced retinopathy. Furthermore, K5-N,OS(H) binds a variety of heparin-binding angiogenic factors upregulated in PDR vitreous humor besides VEGF, thus inhibiting their biological activity. Finally, K5-N,OS(H) hampers the angiogenic activity exerted in vitro and in vivo by human vitreous fluid samples collected from patients with PDR. Together, the data provide compelling experimental evidence that K5-N,OS(H) represents an antiangiogenic multitarget molecule with potential implications for the therapy of pathologic neovessel formation in the retina of patients with PDR.

Hyperglycemia induces altered expressions of angiogenesis associated molecules in the trophoblast

We previously reported that the increased level of perlecan with altered glycosaminoglycan (GAG) substitution was present in the placenta with gestational diabetes mellitus (GDM) and in the trophoblasts cultured under hyperglycemic condition. Trophoblast is the first cell lineage to differentiate, invasive, and migrate into the vessel tissues of placenta and fetal membrane during pregnancy. Therefore, active matrix remodeling and vessel formation must occur during placentation. In this study, we further investigated whether hyperglycemia-induced alterations of perlecan in the extracellular matrix (ECM) affect the proliferation and the expressions of angiogenesis-related growth factors and cytokines in the trophoblasts. 3A-Sub-E trophoblastic cells cultured in high glucose medium were conducted to mimic the hyperglycemic condition. Results showed that the hyperglycemia-induced GAG alterations in the cell surface perlecan as well as in the ECM indeed upregulated the expressions of IL-6, IL-8, and MCP-1 and the activities of MMP-2 and MMP-9 and downregulated the expressions of TIMP-2. A regulatory molecular mechanism of hyperglycemia-induced alterations of the cell surface proteoglycans and the ECM remodeling on the expressions of angiogenesis-related cytokines and growth factors in trophoblasts was proposed. This mechanism may contribute to the aberrant placental structure and the maternal and fetal complications during development.

The non-anticoagulant heparin-like K5 polysaccharide derivative K5-N,OSepi attenuates myocardial ischaemia/reperfusion injury

Heparin and low molecular weight heparins have been demonstrated to reduce myocardial ischaemia/reperfusion (I/R) injury, although their use is hampered by the risk of haemorrhagic and thrombotic complications. Chemical and enzymatic modifications of K5 polysaccharide have shown the possibility of producing heparin-like compounds with low anticoagulant activity and strong anti-inflammatory effects. Using a rat model of regional myocardial I/R, we investigated the effects of an epimerized N-,O-sulphated K5 polysaccharide derivative, K5-N,OSepi, on infarct size and histological signs of myocardial injury caused by 30 min. ligature of the left anterior descending coronary artery followed by 1 or 24 h reperfusion. K5-N,OSepi (0.1-1 mg/kg given i.v. 15 min. before reperfusion) significantly reduced the extent of myocardial damage in a dose-dependent manner. Furthermore, we investigated the potential mechanism(s) of the cardioprotective effect(s) afforded by K5-N,OSepi. In left ventricular samples, I/R induced mast cell degranulation and a robust increase in lipid peroxidation, free radical-induced DNA damage and calcium overload. Markers of neutrophil infiltration and activation were also induced by I/R in rat hearts, specifically myeloperoxidase activity, intercellular-adhesion-molecule-1 expression, prostaglandin-E(2) and tumour-necrosis-factor-α production. The robust increase in oxidative stress and inflammatory markers was blunted by K5-N,OSepi, in a dose-dependent manner, with maximum at 1 mg/kg. Furthermore, K5-N,OSepi administration attenuated the increase in caspase 3 activity, Bid and Bax activation and ameliorated the decrease in expression of Bcl-2 within the ischaemic myocardium. In conclusion, we demonstrate that the cardioprotective effect of the non-anticoagulant K5 derivative K5-N,OSepi is secondary to a combination of anti-apoptotic and anti-inflammatory effects.

Polyphosphate elicits pro-inflammatory responses that are counteracted by activated protein C in both cellular and animal models

BACKGROUND

Recent results have indicated that polyphosphate, released by activated platelets, can function as a procoagulant to modulate the proteolytic activity of serine proteases of the blood clotting cascade.

OBJECTIVE

To determine whether polyphosphate is involved in inducing signal transduction in cellular and animal models.

METHODS

The effect of polyphosphate on human umbilical vein endothelial cells was examined by monitoring cell permeability, apoptosis and activation of NF-κB after treating cells with different concentrations of polyphosphate. Moreover, the expression of cell surface adhesion molecules (VCAM-1, ICAM-1 and E-selectin) and the adhesion of THP-1 cells to polyphosphate-treated cells were monitored using established methods. In the in vivo model, the pro-inflammatory effect of polyphosphate was assessed by monitoring vascular permeability and migration of leukocytes to the peritoneal cavity of mice injected with polyphosphate.

RESULTS

Polyphosphate, comprised of 45, 65 and 70 phosphate units, enhanced the barrier permeability and apoptosis in cultured endothelial cells and up-regulated the expression of cell adhesion molecules, thereby mediating the adhesion of THP-1 cells to polyphosphate-treated endothelial cells. These effects of polyphosphate were mediated through the activation of NF-κB and could not be recapitulated by another anionic polymer, heparin. Polyphosphate also increased the extravasation of the bovine serum albumin (BSA)-bound Evans blue dye and the migration of leukocytes to the mouse peritoneal cavity, which was prevented when activated protein C (APC) was intravenously (i.v.) injected 2 h before the challenge.

CONCLUSION

Polyphosphate, in addition to up-regulation of coagulation, can elicit potent pro-inflammatory responses through the activation of NF-κB, possibly contributing to the pro-inflammatory effect of activated platelets.

Heparosan-derived heparan sulfate/heparin-like compounds: one kind of potential therapeutic agents

Heparan sulfate (HS) is a highly sulfated glycosaminoglycan and exists in all animal tissues. HS and heparin are very similar, except that heparin has higher level of sulfation and higher content of iduronic acid. Despite the fact that it is a century-old drug, heparin remains as a top choice for treating thrombotic disorders. Pharmaceutical heparin is derived from porcine intestine or bovine lung via a long supply chain. This supply chain is vulnerable to the contamination of animal pathogens. Therefore, new methods for manufacturing heparin or heparin-like substances devoid of animal tissues have been explored by many researchers, among which, modifications of heparosan, the capsular polysaccharide of Escherichia coli K5 strain, is one of the promising approaches. Heparosan has a structure similar to unmodified backbone of natural HS and heparin. It is feasible to obtain HS or heparin derivatives by modifying heparosan with chemical or enzymatic methods. These derivatives display different biological activities, such as anticoagulant, anti-inflammatory, anticancer, and antiviral activities. This review focuses on the recent studies of synthesis, activity, and structure-activity relationship of HS/heparin-like derivatives prepared from heparosan.

Recurrence and severity of abnormal pregnancy outcome in patients treated by low-molecular-weight heparin: a prospective pilot study

OBJECTIVE

This prospective pilot study assesses the recurrence rate and severity of abnormal pregnancy outcome (APO), excluding early pregnancy complications, in pregnant patients, without acquired thrombophilia, treated by prophylactic doses of low-molecular-weight heparin (LMWH), independently from their congenital thrombophilic condition.

METHODS

We recruited a cohort of 128 pregnant patients with previous APO; 100 of whom with APO and intrauterine growth restriction (IUGR) and 28 with maternal APO only. LMWH treatment was started at recruitment. Composite cross-over recurrence rate IUGR, gestational hypertension, preeclampsia, help syndrome, abruptio placenta were analyzed. The main outcome measure was severe APOs with iatrogenic delivery ≤ 32 weeks of gestation.

RESULTS

Median gestational age at LMWH treatment was 20 weeks. Severe APO decreased in treated pregnancies from 45% to 4% (relative risk = 0.3, confidence interval 95% = 0.2-0.8). This value was not significantly different in thrombophilic and nonthrombophilic patients. When severe and minor complications were analyzed altogether, the recurrence rate was 28%. In patients with APO and fetal growth restriction (FGR) in the index pregnancy, newborn weights were significantly better in the treated pregnancy: 1090 g (1035-1145) vs. 850 g (535-1200), p < 0.01.

CONCLUSIONS

Prophylactic regimen of LMWH significantly reduced the recurrence rate of severe composite APO in pregnancies affected in the index pregnancy by APO and FGR or small for gestational age newborns. This result was independent from the patients' inherited thrombophilic conditions.

Semi-synthetic heparinoids

New chemical-enzymatic technology based on the modification of the bacterial polysaccharide K5 from Escherichia coli leads to the synthesis of a number of heparin/heparan sulfate-like molecules with different biological activities. With this technology, two families of sulfated compounds were synthesized, which differ in their uronic acid content. The first group contains only glucuronic acid, whereas the second group contains about 50% iduronic acid following epimerization by immobilized recombinant C5 epimerase. This has led to the development of various anticoagulant and nonanticoagulant K5 derivatives endowed with different - and sometimes highly specific - antitumor, antiviral, and/or anti-inflammatory activities.

Treatment with unfractionated heparin attenuates coagulation and inflammation in endotoxemic mice

INTRODUCTION

In the pathogenesis of sepsis, inflammation and coagulation play a pivotal role. In addition to the anticoagulant activity, unfractionated heparin (UFH) has important immunomodulatory properties. However, different studies have reported conflicting effects on sepsis in association with heparin. The objective of this study is to determine whether UFH is able to reduce endotoxin-induced inflammation and coagulation in mice or produce improved outcome.

METHODS

C57BL/6J mice were randomly divided into two groups. Experimental mice were given intravenous injection of 8 units/20 g body weight UFH (heparin sodium) diluted in 20 μl sterile saline while the control mice received vehicle sterile saline only. They were injected with LPS (30 mg/kg, i.p.) 0.5h later. Blood was collected and Livers were harvested at 3 and 6h for analysis. In survival studies, a separate group of mice were treated with 8 units/20 g UFH (n=20) or sterile saline (n=20) given intravenously at 1, 12, 24 and 36 hours after LPS injection. Mice were monitored every 12 hours for a maximum of 72 hrs.

RESULTS

1) Pretreatment of mice with UFH strongly reduced the levels of TNF-α, IL-1β and TAT in plasma at 3 and 6h; 2) Pretreatment of mice with UFH inhibited the expression of TNF-α, IL-1β and tissue factor genes in blood cells at 3h; 3) UFH pretreatment dramatically diminished LPS-induced neutrophil sequestration (at 3 and 6h) , thrombi formation and fibrin(ogen) deposition in the liver (at 6h). 4) The UFH-pretreated group exhibited significantly lower levels of ALT and CRE at 6h. 5) Treatment with UFH could prevent mortality associated with endotoxin challenge.

CONCLUSION

These data suggest that UFH attenuates inflammation and coagulation and prevents lethality in endotoxemic mice.

Anti-inflammatory effects of low molecular weight heparin derivative in a rat model of carrageenan-induced pleurisy

Low molecular weight heparin derivatives are characterized by low anti-coagulant activity and marked anti-inflammatory effects that allow for these molecules to be viewed as a new class of non-steroidal anti-inflammatory drugs (NSAIDs). We show here that K5NOSepiLMW, an O-sulphated heparin-like semi-synthetic polymer of the D-glucuronic acid-N-acetyleparoson disaccharide unit with low molecular weight, has marked anti-inflammatory effects in a rat model of acute inflammation, the carrageenan-induced pleurisy, commonly used to test NSAID efficacy. A 30-min. pre-treatment with K5NOSepiLMW (0.1, 0.5 and 1 mg/kg b.wt., given intrapleurally) attenuated the recruitment of leucocytes in the lung tissue and the pleural exudate, inhibited the induction of inducible nitric oxide synthase and cyclooxygenase-2 (COX-2), thereby abating the generation of nitric oxide and pro-inflammatory prostaglandins such as PgE(2) and PGF(1alpha), reduced the inflammation-induced nitroxidative lung tissue injury, as shown by tissue thiobarbituric acid-reactive substances and nitrotyrosine, and blunted the local generation of cytokines such as interleukin-1beta and tumour necrosis factor-alpha. All these parameters were markedly increased by intrapleural carrageenan in the absence of any pre-treatment. The anti-inflammatory action of K5NOSepiLMW is specific, as judged by the lack of therapeutic effects of B4/110, a biologically inactive cognate polysaccharide, given in the place of the authentic molecule. Moreover, K5NOSepiLMW showed similar effects as celecoxib (1 mg/kg b.wt), a COX-2 inhibitor and well-known NSAID. This study provides further insight into the mechanisms underlying the beneficial effects of heparin derivatives in inflammation and identifies K5NOSepiLMW as a novel, promising anti-inflammatory drug.

Anti-inflammatory effects of low molecular weight heparin derivative in a rat model of carrageenan-induced pleurisy

Low molecular weight heparin derivatives are characterized by low anti-coagulant activity and marked anti-inflammatory effects that allow for these molecules to be viewed as a new class of non-steroidal anti-inflammatory drugs (NSAIDs). We show here that K5NOSepiLMW, an O-sulphated heparin-like semi-synthetic polymer of the D-glucuronic acid-N-acetyleparoson disaccharide unit with low molecular weight, has marked anti-inflammatory effects in a rat model of acute inflammation, the carrageenan-induced pleurisy, commonly used to test NSAID efficacy. A 30-min. pre-treatment with K5NOSepiLMW (0.1, 0.5 and 1 mg/kg b.wt., given intrapleurally) attenuated the recruitment of leucocytes in the lung tissue and the pleural exudate, inhibited the induction of inducible nitric oxide synthase and cyclooxygenase-2 (COX-2), thereby abating the generation of nitric oxide and pro-inflammatory prostaglandins such as PgE(2) and PGF(1alpha), reduced the inflammation-induced nitroxidative lung tissue injury, as shown by tissue thiobarbituric acid-reactive substances and nitrotyrosine, and blunted the local generation of cytokines such as interleukin-1beta and tumour necrosis factor-alpha. All these parameters were markedly increased by intrapleural carrageenan in the absence of any pre-treatment. The anti-inflammatory action of K5NOSepiLMW is specific, as judged by the lack of therapeutic effects of B4/110, a biologically inactive cognate polysaccharide, given in the place of the authentic molecule. Moreover, K5NOSepiLMW showed similar effects as celecoxib (1 mg/kg b.wt), a COX-2 inhibitor and well-known NSAID. This study provides further insight into the mechanisms underlying the beneficial effects of heparin derivatives in inflammation and identifies K5NOSepiLMW as a novel, promising anti-inflammatory drug.

The effect of erythropoietin on microcirculation perfusion and tissue bioenergetics of the small intestine in a hemorrhagic shock and resuscitation rat model

BACKGROUND

Erythropoietin (EPO) can exert acute hemodynamic and anti-inflammatory effects in addition to erythropoiesis. We tested the hypothesis that EPO given at resuscitation with saline will improve capillary perfusion and tissue oxygenation in the gut using a hemorrhagic shock model.

METHODS

Sprague-Dawley rats were bled 30 mL/kg to maintain a mean arterial blood pressure of 40 mm Hg for 50 minutes and then randomized to one of four resuscitation groups (n = 6 per group): blood, blood + recombinant human EPO (rHuEPO), saline, and saline + rHuEPO. Intravenous rHuEPO (1,000 U/kg) was given at the start of resuscitation. Intravital microscopy was used to measure perfused capillary density, flow motion of red blood cell (RBC), and tissue NADH fluorescence 60 minutes after resuscitation. Venous oxygenation saturation (Svo2) was also measured in a second experiment.

RESULTS

In the blood +/- rHuEPO resuscitation group, the perfused capillary density, RBC flow motion scores, and NADH fluorescence returned to near normal values. The saline + rHuEPO group compared with the saline group demonstrated an increased RBC flow motion score (2.32 vs. 1.60; p < 0.01); however, the perfused capillary density was not significantly increased (23.03 Cap/mm vs. 21.61 Cap/mm; p = 0.40). The saline + rHuEPO group also demonstrated statistically significant lower NADH fluorescence than the saline group after shock following resuscitation (110% +/- 3.64% vs. 122% +/- 4.26%; p < 0.05) suggesting decreased tissue dysoxia. The Svo2 in the saline + rHuEPO group was higher when compared with the saline group (45% vs. 38% by continuous oximetry; 38% vs. 29% by co-oximetry; p < 0.05).

CONCLUSION

Our results suggest that the addition of rHuEPO at the time of saline resuscitation may have beneficial effects in hemorrhagic shock by improving tissue perfusion and decreasing dysoxia in the gut.

The anti-inflammatory effects of heparin and related compounds

Heparin is a glycosaminoglycan well known for its anticoagulant properties. In addition, heparin possesses anti-inflammatory effects. Although the mechanisms responsible for the anticoagulant effects of heparin are well understood, those underlying its anti-inflammatory effects are not. This review presents some of the evidence from clinical and animal studies supporting an anti-inflammatory role for heparin and heparin-related derivatives. Potential mechanisms by which heparin can exert its anti-inflammatory effects are discussed. The clinical use of heparin as an anti-inflammatory agent has been held back by the fear of bleeding. Development of nonanticoagulant heparins or heparin derivatives should mitigate this concern.

Roles of cellular activation and sulfated glycans in Haemophilus somnus adherence to bovine brain microvascular endothelial cells

Haemophilus somnus can cause a devastating fibrinopurulent meningitis with thrombotic vasculitis and encephalitis in cattle. The mechanisms used by H. somnus to migrate from the bloodstream into the central nervous system (CNS) are unknown. In this study, we demonstrate that H. somnus adheres to, but does not invade, bovine brain endothelial cells (BBEC) in vitro. The number of adherent H. somnus was significantly increased by prior activation of the BBEC with tumor necrosis factor alpha (TNF-alpha). Addition of exogenous glycosaminoglycans significantly reduced H. somnus adherence to resting and TNF-alpha-activated BBEC. Heparinase digestion of the endothelial cell's glycocalyx or sodium chlorate inhibition of endothelial cell sulfated glycan synthesis significantly reduced the number of adherent H. somnus. In contrast, addition of hyaluronic acid, a nonsulfated glycosaminoglycan, had no inhibitory effect. These findings suggest a critical role for both cellular activation and sulfated glycosaminoglycans in adherence of H. somnus to BBEC. Using heparin-labeled agarose beads, we demonstrated a high-molecular-weight heparin-binding protein expressed by H. somnus. Heparin was also shown to bind H. somnus in a 4 degrees C binding assay. These data suggest that heparin-binding proteins on H. somnus could serve as initial adhesins to sulfated proteoglycans on the endothelial cell surface, thus contributing to the ability of H. somnus to infect the bovine CNS.

Effects of unfractionated heparin and low-molecular-weight heparin on colonic anastomoses in the presence of experimental peritonitis

BACKGROUND

We aimed at investigating the effects of unfractionated heparin (UFH) and low-molecular-weight heparin (LMWH) on the healing process of colonic anastomoses in the presence of peritonitis which is known to adversely affect the healing process.

STUDY DESIGN

Three groups of Wistar albino rats (n = 15 in each group) with experimental fecal peritonitis were studied. A 1-cm colonic segment was resected, and an end-to-end anastomosis was performed. The control group (group 1) was given no treatment; group 2 animals received 50 IU/kg s.c. UFH twice a day, and group 3 rats received LMWH at a dose of 1.5 mg/kg daily for 7 days postoperatively. Relaparotomy was done on day 7 in the surviving rats. The rats were sacrificed by resection of the colonic segment. The anastomosis bursting pressures were measured and the tissue samples from anastomosis lines were histopathologically examined.

RESULTS

The bursting pressures were significantly higher in UFH and LMWH groups as compared with the controls (p = 0.021 and p < 0.001, respectively), while there was no statistically significant difference between UFH and LMWH groups. Positive bacterial culture results were more common in controls (90%) than in the other two groups (p = 0.029 and p = 0.002, respectively). Also the polymorphonuclear leukocyte counts were higher (p = 0.005) and the fibrin formation more common (p = 0.007) in the controls. On the other hand, the number of fibroblasts was higher (p = 0.002) and collagen formation and revascularization more frequent (p = 0.001 and p = 0.001, respectively) in the UFH and LMWH groups.

CONCLUSION

UFH and LMWH may have positive effects on the healing process of colonic anastomoses in the presence of peritonitis.

Low-molecular weight and unfractionated heparins induce a downregulation of inflammation: decreased levels of proinflammatory cytokines and nuclear factor-kappaB in LPS-stimulated human monocytes

Unfractionated heparin (UFH) and low-molecular weight heparin (LMWH) are well defined anticoagulant agents. Recent data suggest that both LMWH and UFH may also have potent anti-inflammatory properties; however, their mechanism of action responsible for the anti-inflammatory effect is not yet fully elucidated. This study was designed to assess the effect of LMWH and UFH on human monocytes production of inflammatory markers and nuclear translocation of nuclear factor (NF)-kappaB. Cultured monocytes were pretreated for 15 min with LMWH or UFH (10 microg and 1 microg/million cells) before stimulation with lipopolysaccharide (LPS) at a dose of 1 ng/million cells. Proinflammatory cytokines tumour necrosis factor (TNF)-alpha, interleukin (IL)-8, IL-6 and IL-1beta release were subsequently measured by enzyme-linked immunosorbent assay at 6 h, and nuclear translocation of the proinflammatory NF-kappaB was assessed at 2 h. Treatment with pharmacological doses of LMWH and UFH significantly attenuated LPS-induced production of TNF-alpha, IL-8, IL-6 and IL-1beta as well as NF-kappaB translocation. These results indicate equivalent and significant heparin anti-inflammatory properties at low doses on monocyte-mediated immune response. The inhibition of NF-kappaB activation certainly represents one of the mechanisms by which heparin exerts its anti-inflammatory effect. LMWH and UFH therefore appear as potential therapeutic inhibitors of inflammation.