Orally Administered Enoxaparin Ameliorates Acute Colitis by Reducing Macrophage-Associated Inflammatory Responses.

Inflammatory bowel diseases, such as ulcerative colitis, cause significant morbidity and decreased quality of life. The currently available treatments are not effective in all patients, can be expensive and have potential to cause severe side effects. This prompts the need for new treatment modalities. Enoxaparin, a widely used antithrombotic agent, is reported to possess anti-inflammatory properties and therefore we evaluated its therapeutic potential in a mouse model of colitis. Acute colitis was induced in male C57BL/6 mice by administration of dextran sulfate sodium (DSS). Mice were treated once daily with enoxaparin via oral or intraperitoneal administration and monitored for colitis activities. On termination (day 8), colons were collected for macroscopic evaluation and cytokine measurement, and processed for histology and immunohistochemistry. Oral but not intraperitoneal administration of enoxaparin significantly ameliorated DSS-induced colitis. Oral enoxaparin-treated mice retained their body weight and displayed less diarrhea and fecal blood loss compared to the untreated colitis group. Colon weight in enoxaparin-treated mice was significantly lower, indicating reduced inflammation and edema. Histological examination of untreated colitis mice showed a massive loss of crypt architecture and goblet cells, infiltration of immune cells and the presence of edema, while all aspects of this pathology were alleviated by oral enoxaparin. Reduced number of macrophages in the colon of oral enoxaparin-treated mice was accompanied by decreased levels of pro-inflammatory cytokines. Oral enoxaparin significantly reduces the inflammatory pathology associated with DSS-induced colitis in mice and could therefore represent a novel therapeutic option for the management of ulcerative colitis.

Non-Anticoagulant Fractions of Enoxaparin Suppress Inflammatory Cytokine Release from Peripheral Blood Mononuclear Cells of Allergic Asthmatic Individuals.

BACKGROUND: Enoxaparin, a low-molecular-weight heparin, is known to possess anti-inflammatory properties. However, its clinical exploitation as an anti-inflammatory agent is hampered by its anticoagulant effect and the associated risk of bleeding. OBJECTIVE: The aim of the current study was to examine the ability of non-anticoagulant fractions of enoxaparin to inhibit the release of key inflammatory cytokines in primed peripheral blood mononuclear cells derived from allergic mild asthmatics. METHODS: Peripheral blood mononuclear cells from allergic asthmatics were activated with phytohaemag glutinin (PHA), concanavalin-A (ConA) or phorbol 12-myristate 13-acetate (PMA) in the presence or absence of enoxaparin fractions before cytokine levels were quantified using specific cytokine bead arrays. Together with nuclear magnetic resonance analysis,time-dependent and target-specific effects of enoxaparin fractions were used to elucidate structural determinants for their anti-inflammatory effect and gain mechanistic insights into their anti-inflammatory activity. RESULTS: Two non-anticoagulant fractions of enoxaparin were identified that significantly inhibited T-cell activation. A disaccharide fraction of enoxaparin inhibited the release of IL-4, IL-5, IL-13 and TNF-α by more than 57% while a tetrasaccharide fraction was found to inhibit the release of tested cytokines by more than 68%. Our data suggest that the observed response is likely to be due to an interaction of 6-O-sulfated tetrasaccharide with cellular receptor(s). CONCLUSION AND CLINICAL RELEVANCE: The two identified anti-inflammatory fractions lacked anticoagulant activity and are therefore not associated with risk of bleeding. The findings highlight the potential therapeutic use of enoxaparin-derived fractions, in particular tetrasaccharide, in patients with chronic inflammatory disorders.

In-vitro suppression of IL-6 and IL-8 release from human pulmonary epithelial cells by non-anticoagulant fraction of enoxaparin.

BACKGROUND: Enoxaparin, a mixture of anticoagulant and non-anticoagulant fractions, is widely used as an anticoagulant agent. However, it is also reported to possess anti-inflammatory properties. Our study indicated that enoxaparin inhibits the release of IL-6 and IL-8 from A549 pulmonary epithelial cells. Their release causes extensive lung tissue damage. The use of enoxaparin as an anti-inflammatory agent is hampered due to the risk of bleeding associated with its anticoagulant fractions. Therefore, we aimed to identify the fraction responsible for the observed anti-inflammatory effect of enoxaparin and to determine the relationship between its structure and biological activities. METHODS: A549 pulmonary epithelial cells were pre-treated in the presence of enoxaparin and its fractions. The levels of IL-6 and IL-8 released from the trypsin-stimulated cells were measured by ELISA. The anticoagulant activity of the fraction responsible for the effect of enoxaparin was determined using an anti-factor-Xa assay. The fraction was structurally characterised using nuclear magnetic resonance. The fraction was 2-O, 6-O or N-desulfated to determine the position of sulfate groups required for the inhibition of interleukins. High-performance size-exclusion chromatography was performed to rule out that the observed effect was due to the interaction between the fraction and trypsin or interleukins. RESULTS: Enoxaparin (60 µg/mL) inhibited the release of IL-6 and IL-8 by >30%. The fraction responsible for this effect of enoxaparin was found to be a disaccharide composed of α-L-iduronic-acid and α-D-glucosamine-6-sulfate. It (15 µg/mL) inhibited the release of interleukins by >70%. The 6-O sulphate groups were responsible for its anti-inflammatory effect. The fraction did not bind to trypsin or interleukins, suggesting the effect was not due to an artefact of the experimental model. CONCLUSION: The identified disaccharide has no anticoagulant activity and therefore eliminates the risk of bleeding associated with enoxaparin. Future in-vivo studies should be designed to validate findings of the current study.

Opposing effects of low molecular weight heparins on the release of inflammatory cytokines from peripheral blood mononuclear cells of asthmatics.

BACKGROUND: T-cell-mediated inflammatory cytokines, such as interleukin (IL)-4, IL-5, IL-13 and tumor necrosis factor-alpha (TNF-α), play an important role in the initiation and progression of inflammatory airways diseases. Low-molecular-weight heparins (LMWHs), widely used anticoagulants, possess anti-inflammatory properties making them potential treatment options for inflammatory diseases, including asthma. In the current study, we investigated the modulating effects of two LMWHs (enoxaparin and dalteparin) on the release of cytokines from stimulated peripheral blood mononuclear cells (PBMCs) of asthmatic subjects to identify the specific components responsible for the effects. METHODS: PBMCs from asthmatic subjects (consist of ~75% of T-cells) were isolated from blood taken from ten asthmatic subjects. The PBMCs were pre-treated in the presence or absence of different concentrations of LMWHs, and were then stimulated by phytohaemagglutinin for the release of IL-4, IL-5, IL-13 and TNF-α. LMWHs were completely or selectively desulfated and their anticoagulant effect, as well as the ability to modulate cytokine release, was determined. LMWHs were chromatographically fractionated and each fraction was tested for molecular weight determination along with an assessment of anticoagulant potency and effect on cytokine release. RESULTS: Enoxaparin inhibited cytokine release by more than 48%, whereas dalteparin increased their release by more than 25%. The observed anti-inflammatory effects of enoxaparin were independent of their anticoagulant activities. Smaller fractions, in particular dp4 (four saccharide units), were responsible for the inhibitory effect of enoxaparin. Whereas, the larger fractions, in particular dp22 (twenty two saccharide units), were associated with the stimulatory effect of dalteparin. CONCLUSION: Enoxaparin and dalteparin demonstrated opposing effects on inflammatory markers. These observed effects could be due to the presence of structurally different components in the two LMWHs arising from different methods of depolymerisation. This study provides a platform for further studies investigating the usefulness of enoxaparin in various inflammatory diseases.

Genetic variation in PBMC-produced IFN-γ and TNF-α associations with relapse in multiple sclerosis.

BACKGROUND: Alterations in peripheral blood mononuclear cell (PBMC) cytokine production have been found in multiple sclerosis (MS) compared to healthy controls. We have previously found that stimulated PBMC-produced TNF-α and IFN-γ modulated MS relapse risk, such that raised TNF-α was protective, while raised IFN-γ increased relapse risk. OBJECTIVE: To assess whether SNPs within genes for relevant cytokines and their receptors modulate the associations of TNF-α and IFN-γ with relapse, thus providing additional information about these cytokine effects and the roles of these genes in MS. METHODS: Prospective cohort of 91 participants with relapsing-remitting MS and cytokine and genotype data. SNPs (N=361) within a window of 10 kb around each cytokine/cytokine receptor gene (N=84) were selected for analysis. Predictors of PBMC cytokines were evaluated by multilevel mixed-effects linear regression. Predictors of relapse were evaluated by Cox proportional hazards regression. Bonferroni correction was used to adjust for multiple testing; thus p<1.39 × 10(-4) was defined as significant. RESULTS: Individuals of GG genotype of rs3218295 (within the gene IL2RB) demonstrated a significant protective effect of TNF-α on relapse while those of GA/AA genotype showed a significant positive association (pinteraction=5.04 × 10(-5)). Carriers of CC genotype of rs522807 (3' region of TNFRSF1B) and the AA genotype of rs25879 (5' region of IL3) showed a strong association between IFN-γ and increased relapse risk (pinteraction=8.21 × 10(-5) and 1.70 × 10(-5), respectively). CONCLUSIONS: Our results show novel modulation of TNF-α and IFN-γ associations with relapse by SNPs in major cytokines. These findings suggest the potential for these genes and/or their products as potential therapeutic targets in MS.

Stimulated PBMC-produced IFN-γ and TNF-α are associated with altered relapse risk in multiple sclerosis: results from a prospective cohort study.

BACKGROUND: Altered reactivity of peripheral blood mononuclear cells (PBMC) and their production of cytokines may affect multiple sclerosis (MS) clinical course. We assessed the relationship of stimulated PBMC-produced IFN-γ, TNF-α, IL-4 and IL-10 in modulating relapse risk using a prospective cohort with established relapsing-remitting MS. METHODS: Cytokine production from PBMCs taken in summer and winter was measured by ELISA. Predictors of cytokines assessed by multilevel mixed-effects linear regression. Predictors of relapse assessed by survival analysis. RESULTS: Increasing IFN-γ was associated with increasing relapse risk, while increasing TNF-α reduced relapse risk after adjusting for IFN-γ. IL-10 and IL4 were not consistently associated with relapse risk. IFN-γ's effects on relapse were greatly attenuated by immunomodulatory therapies, by summer season and by higher serum vitamin D, whereas TNF-α's inverse association with relapse was only present in these circumstances. The TNF-α inverse association with relapse was only present among persons carrying the wild-type of the functional SNP rs1800693 in TNFRSF1A that has been previously associated with MS risk. CONCLUSIONS: We found strong effects of IFN-γ and TNF-α on relapse risk, these differing by immunomodulatory therapy, season, and serum vitamin D, as well as by genotype. These results indicate altered reactivity of immune cells modulate MS disease.

Identification of pro- and anti-proliferative oligosaccharides of heparins.

Heparins, unfractionated heparin (UFH) and low molecular weight heparins (LMWHs), are heterogeneous mixtures of anticoagulant and non-anticoagulant oligosaccharides. In addition to their well-known anticoagulant effect, heparins have shown to mediate a wide range of non-anticoagulant effects, including the modulation of cellular growth. However, contradictory results have been reported with regard to their effects on cellular proliferation, with some studies suggesting anti-proliferative while others indicating pro-proliferative effects. This study investigated the proliferation of human colonic epithelial cancer cells in the presence of UFH and LMWHs (enoxaparin and dalteparin). In our experimental setting, all heparins caused a dose-dependent reduction in cellular growth, which correlated well with the induction of cell cycle arrest in the G1 phase and which was not associated with significant changes in cell viability. The effects on cellular proliferation of 14 different oligosaccharides of enoxaparin obtained through ion-exchange chromatography were also assessed. Surprisingly, only two oligosaccharides showed distinctive anti-proliferative effects while the majority of oligosaccharides actually stimulated proliferation. Interestingly, the smallest oligosaccharide devoid of any anticoagulant activity showed the strongest anti-proliferative effect. Notably, heparins are currently standardised only according to their anticoagulant activity but not based on other non-anticoagulant properties. Our results indicate that slight differences in the composition of heparins' non-anticoagulant oligosaccharides, due to different origins of material and preparation methods, have the potential to cause diverse effects and highlight the need for additional characterisation of non-anticoagulant activities.

Sputum neutrophils in cystic fibrosis patients display a reduced respiratory burst.

BACKGROUND: Few data exist on the functional activity of airway neutrophils in the milieu of the cystic fibrosis (CF) lung. We assessed reactive oxygen species (ROS) production by sputum neutrophils and the relationship to neutrophil viability. Identical assessments were made on peripheral blood neutrophils from CF patients. METHODS: ROS production in sputum neutrophils was assessed in 31 CF patients at varying phases of clinical disease using flow cytometry. Twenty patients provided blood samples (including 16 who also provided a matched sputum sample). Neutrophil viability was determined using dual annexin V (apoptosis) and propidium iodide (necrosis) staining. Comparative peripheral blood data were obtained from 7 healthy controls. RESULTS: ROS production was reduced in sputum compared to blood neutrophils and they demonstrated a higher level of necrosis. Subpopulations of neutrophils with different ROS production capacity were apparent in peripheral blood. Lung function was positively associated with both the proportion of blood neutrophils demonstrating increased ROS production and the proportion of apoptotic sputum neutrophils. CONCLUSIONS: CF airway neutrophils display functional exhaustion. Healthier lungs in CF appear to be associated with subpopulations of blood neutrophils with increased oxidative burst capacity and evidence for increased neutrophil apoptosis within the airway.

Interferon-ß and serum 25-hydroxyvitamin D interact to modulate relapse risk in MS.

OBJECTIVE: To determine whether interferon-ß (IFN-ß) medication use is associated with vitamin D levels and whether the two interact in exerting effects on relapse risk. METHODS: In a prospective cohort of 178 persons with clinically definite multiple sclerosis (MS) living in southern Tasmania in 2002-2005, serum 25-hydroxyvitamin D [25(OH)D] was measured biannually, with assessment by questionnaire for relevant factors, including IFN-ß treatment. RESULTS: Subjects reporting IFN-ß use had significantly higher mean 25(OH)D than persons who did not (p < 0.001). This was mediated by an interaction between personal sun exposure and IFN-ß, with treated persons realizing nearly three times 25(OH)D per hour of sun exposure of persons not on therapy. The association between 25(OH)D and 1,25-dihydroxyvitamin D did not differ by IFN-ß therapy (p = 0.82). 25(OH)D was associated with a reduced relapse risk only among persons on IFN-ß (p < 0.001). Importantly, IFN-ß was only protective against relapse among persons with higher 25(OH)D (hazard ratio [HR] 0.58 [95% confidence interval (CI) 0.35-0.98]), while among 25(OH)D-insufficient persons, IFN-ß increased relapse risk (HR 2.01 [95% CI 1.22-3.32]). CONCLUSION: In this study, we found that IFN-ß therapy is associated with greater production of vitamin D from sun exposure, suggesting part of the therapeutic effects of IFN-ß on relapse in MS may be through modulation of vitamin D metabolism. These findings suggest persons being treated with IFN-ß should have vitamin D status monitored and maintained in the sufficiency range. CLASSIFICATION OF EVIDENCE: This study provided Class III evidence that IFN-ß is associated with reduced risk of relapse, and this effect may be modified by a positive effect of IFN-ß on serum 25(OH)D levels.