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

TILE pilot trial study protocol: Tinzaparin Lead-in to Prevent the Post-Thrombotic syndrome study protocol

INTRODUCTION

The post-thrombotic syndrome (PTS) is a form of chronic venous insufficiency due to a prior ipsilateral deep venous thrombosis (DVT). This is a frequent complication that develops in 20%-50% of patients after a proximal DVT and is associated with significant healthcare, economic and societal consequences. In the absence of effective and well-tolerated treatment options for established PTS, effective preventative measures are needed. Anticoagulation itself reduces the risk of PTS, and low-molecular-weight heparin may reduce this further through anti-inflammatory properties targeting the initial acute inflammatory phase of DVT.

METHODS AND ANALYSIS

The Tinzaparin Lead-In to Prevent the Post-Thrombotic syndrome pilot trial is an investigator-initiated, multicentre, open-label assessor-blinded trial that will randomise patients with first acute symptomatic common femoral or iliac DVT to receive either a 3-week lead-in course of tinzaparin, followed by rivaroxaban (experimental arm) or rivaroxaban alone (control arm). Its primary objectives are to assess: (1) proportion of PTS at 6 months using the Villalta scale and (2) study feasibility, which consists of (a) the proportion of screened patients eligible for the study, (2) the proportion of eligible patients recruited and (c) the proportion of recruited patients adherent to treatment (defined as at least 80% of drug taken). This study will determine the feasibility of a subsequent larger definitive trial. Secondary outcomes include change of quality of life scores, PTS severity, global improvement, patient satisfaction, bleeding, recurrent venous thromboembolism, leg pain, death and lost to follow-up. Target recruitment will be a total of 60 participants, recruited at 5-6 centres.

ETHICS AND DISSEMINATION

Primary ethics approval was received from the Sunnybrook Health Sciences Center Research Ethics Board (approval ID 3315). Results of the study will be disseminated via peer-reviewed presentation at scientific conferences and open access publication.

TRIAL REGISTRATION NUMBER

NCT04794569.

Bioceramic and polycationic biopolymer nanocomposite scaffolds for improved wound self-healing and anti-inflammatory properties: an in vitro study

The development of wound healing scaffolds with high porosity, rapid healing properties, and anti-inflammatory functionality is vital in the chronic wound healing stage for the production of extracellular matrices of injured tissues. The 45S5 bioactive glass (BG) possesses good biocompatibility and provides a potential bonding resource for fibroblast cell proliferation, growth factor synthesis, and granulated tissue formation. Chitosan, a natural polymer, promotes tissue regeneration and has anti-microbial properties. BG and chitosan scaffolds were prepared by the freeze-drying (lyophilization) method. The chitosan scaffold is a semi-crystalline polymer with a random crystal structure because it contains more hydroxyl groups. Chitosan alone shows a sheet-like morphology with a porous microstructure (1.7475 nm). BG particulates were well decorated over the surface of the chitosan scaffold with a homogeneous dispersion. Cell viability was observed for L929 cells on the chitosan-BG scaffolds. Confocal images vividly depict the interaction of the L929 cells with the scaffold without causing any damage to the cell membrane. In vitro scratch assay shows the best wound healing activity (complete wound closure) for the BG-chitosan nanocomposite scaffolds at 18 h. The chitosan-BG scaffolds were combined with anti-inflammatory drugs and induced inflammatory genes at an inhibition rate of COX of (36, 28, and 30%), LOX of (20, 13, and 14%), and NO of (48, 38, and 39%) for chitosan, chitosan-BG, and chitosan-BG (Na-free) at 100 μL addition. The in vitro bioactivities proved that the chitosan-BG scaffolds could enable better cell formation, and exhibited improved biocompatibility, and anti-inflammatory and wound healing properties.

Prevention of the post thrombotic syndrome with anticoagulation: a narrative review

The post thrombotic syndrome (PTS) is chronic venous insufficiency secondary to a prior deep vein thrombosis (DVT). It is the most common complication of VTE and, while not fatal, it can lead to chronic, unremitting symptoms as well as societal and economic consequences. The cornerstone of PTS treatment lies in its prevention after DVT. Specific PTS preventative measures include the use of elastic compression stockings (ECS) and pharmacomechanical catheter directed thrombolysis (PCDT). However, the efficacy of these treatments has been questioned by large RCTs. So far, anticoagulation, primarily prescribed to prevent DVT extension and recurrence, appears to be the only unquestionably effective treatment for the prevention of PTS. In this literature review we present pathophysiological, biological, radiological and clinical data supporting the efficacy of anticoagulants to prevent PTS and the possible differential efficacy among available classes of anticoagulants (vitamin K antagonists (VKA), low molecular weight heparins (LMWHs) and direct oral anticoagulants (DOACs)). Data suggest that LMWHs and DOACs are superior to VKAs, but no head-to-head comparison is available between DOACs and LMWHs. Owing to their potentially greater anti-inflammatory properties, LMWHs could be superior to DOACs. This finding may be of interest particularly in patients with extensive DVT at high risk of moderate to severe PTS, but needs to be confirmed by a dedicated RCT.

The survival benefit of low molecular weight heparin over unfractionated heparin in pediatric trauma patients

INTRODUCTION

Venous thromboembolism (VTE) prophylaxis in pediatric patients is controversial and is mainly dependent on protocols derived from adult practices. Our study aimed to compare outcomes among pediatric trauma patients who received low molecular weight heparin (LMWH) compared to those who received unfractionated heparin (UFH).

METHODS

We performed 2 years (2015-2016) retrospective analysis of the Pediatrics ACS-TQIP database. Pediatric trauma patients (age ≤17) who received thromboprophylaxis with either LMWH or UFH were included. Patients were stratified into three age groups. Analysis of each subgroup and the entire cohort was performed. Outcome measures included VTE events (deep vein thrombosis [DVT] and pulmonary embolism [PE]), hospital and ICU length of stay (LOS) among survivors, and mortality. Propensity score matching was used to match the two cohorts LMWH vs UFH.

RESULTS

A matched cohort of 1,678 pediatric trauma patients was analyzed. A significant difference in survival, DVT events, and in-hospital LOS was seen in the age groups above 9 years. Overall, the patients who received LMWH had lower mortality (1.4% vs 3.6%, p<0.01), DVT (1.7% vs 3.7%, p<0.01), and hospital LOS among survivors (7 days vs 9 days, p<0.01) compared to those who received UFH. There was no significant difference in the ICU LOS among survivors and the incidence of PE between the two groups.

CONCLUSION

LMWH is associated with increased survival, lower rates of DVT, and decreased hospital LOS compared to UFH among pediatric trauma patients age 10-17 years.

LEVEL OF EVIDENCE

Level III Prophylactic.

STUDY TYPE

Prophylactic.

Anti-Cancer Activity of Porphyran and Carrageenan from Red Seaweeds

Seaweeds are some of the largest producers of biomass in the marine environment and are rich in bioactive compounds that are often used for human and animal health. Porphyran and carrageenan are natural compounds derived from red seaweeds. The former is a characteristic polysaccharide of Porphyra, while the latter is well known from Chondrus, Gigartina, and various Eucheuma species, all in Rhodophyceae. The two polysaccharides have been found to have anti-cancer activity by improving immunity and targeting key apoptotic molecules and therefore deemed as potential chemotherapeutic or chemopreventive agents. This review attempts to review the current study of anti-cancer activity and the possible mechanisms of porphyran and carrageenan derived from red seaweeds to various cancers, and their cooperative actions with other anti-cancer chemotherapeutic agents is also discussed.

The effectiveness of heparin, platelet-rich plasma (PRP), and silver nanoparticles on prevention of postoperative peritoneal adhesion formation in rats

Purpose:

To assess the effectiveness of heparin, platelet-rich plasma (PRP), and silver nanoparticles on prevention of postoperative adhesion in animal models.

Methods:

Sixty males Albino Wistar rats aged 5 to 6 weeks were classified into five groups receiving none, heparin, PRP, silver nanoparticles, PRP plus silver nanoparticles intraperitoneally. After 2 weeks, the animals underwent laparotomy and the damaged site was assessed for peritoneal adhesions severity.

Results:

The mean severity scores were 2.5 ± 0.9, 2.16 ± 0.7, 1.5 ± 0.5, 2.66 ± 0.88, and 2.25 ± 0.62 in the control, heparin, PRP, silver and PRP plus silver groups, respectively with significant intergroup difference (p = 0.004). The highest effective material for preventing adhesion formation was PRP followed by heparin and PRP plus silver. Moreover, compared to the controls, only use of PRP was significantly effective, in terms of adhesion severity (p = 0.01) .

Conclusion:

Platelet-rich plasma alone may have the highest efficacy for preventing postoperative peritoneal adhesions in comparison with heparin, silver nanoparticles and PRP plus silver nanoparticles.

Improved vascularization of porous scaffolds through growth factor delivery from heparinized polyethylene glycol hydrogels

Surface modification with heparin has previously been shown to increase vascularization of porous scaffolds. In order to determine its efficacy with sustained release, heparin (Hep) was covalently incorporated into degradable (Type D) and non-degradable (Type N) polyethylene glycol (PEG) hydrogels. After in vitro characterization of their physicochemical properties, growth factor (GF) loaded, heparinised Type D gels were formed within the pores of porous polyurethane disks, which were then implanted and evaluated in a subcutaneous model. Type N gels formed faster (3.1±0.1 vs. 7.2±0.2min), were stiffer (10.0±0.5kPa vs. 7.1±1.2kPa) and more stable than degradable gels (>6month stability vs. disintegration ⩽22d in vitro; all p<0.001). Sustained release of covalently incorporated (CI) heparin from Type N (56days; first order kinetics) and Type D (21days; zero order kinetics) was achieved, as opposed to non-covalently incorporated (NI) heparin that eluted in a burst release within the first 2days. While Type D gels initially impeded tissue ingrowth into the porous scaffolds, they were completely degraded and replaced by ingrown tissue after 28days in vivo. At the latter timepoint disks containing gels without Hep or with non-covalently incorporated Hep were less vascularized than empty (no gel) controls. In contrast, the incorporation of covalently heparinized (no GF) and GF containing gels (no Hep) resulted in a 50% and 42% (p<0.05) improvement in vascularization, while an increase of 119% (p<0.001) was achieved with a combination of covalently attached Hep and GF. These gels thus provide a sustained release system for heparin and GF that extends the duration of their action to local tissue ingrowth.

STATEMENT OF SIGNIFICANCE

The paper describes the modification and covalent incorporation of heparin into degradable and non-degradable polyethylene glycol hydrogels in a way that provides for the hydrolytic cleavage of the linker for the release of the heparin in original and active form, and in an extended (21-56d) controlled (zero and first order respectively) manner. The successful use of these gels as growth-factor containing and releasing matrices for the improvement of in vivo vascularization holds promise for many potential uses in tissue engineering and regenerative medicine applications, such as vascular grafts and myocardial infarction therapy, where the antithrombotic and/or growth factor binding/potentiating properties are required.

Role of MCP-1 in pleural effusion development in a carrageenan-induced murine model of pleurisy

BACKGROUND AND OBJECTIVE

Exudative pleural effusions affect over 1500 patients per million population each year. The pathobiology of pleural exudate formation remains unclear. Our recent study revealed monocyte chemotactic protein-1 (MCP-1) as a key driver of fibrinolytic-induced exudate effusion while another study found a role for MCP-1 in malignant effusion formation. In the present study, we further evaluated the role of MCP-1 in the development of pleural effusion in a mouse model of acute pleural inflammation.

METHODS

λ-Carrageenan (CAR) was injected into the pleural cavity of CD1 mice and pleural effusion volume measured up to 16 h post-injection. Pleural effusion and serum protein and MCP-1 concentrations were measured and differential cell counts performed in fluids. Mice were also treated with either intraperitoneal (i) anti-MCP-1 antibody or isotype control or (ii) an MCP-1 receptor (CCR2) antagonist or vehicle control 12 h prior to and at the time of CAR injection.

RESULTS

Intrapleural CAR induced significant pleural fluid accumulation (300.0 ± 49.9 μL) in mice after 4 h. Pleural fluid MCP-1 concentrations were significantly higher than corresponding serum MCP-1 (144 603 ± 23 204 pg/mL vs 3703 ± 801 pg/mL, P < 0.0001). A significant decrease in pleural fluid formation was seen both with anti-MCP-1 antibody (median (interquartile range, IQR): 36 (0-168) μL vs controls 290 (70-436) μL; P = 0.02) or CCR2 antagonist (153 (30-222) μL vs controls 240 (151-331) μL, P = 0.0049).

CONCLUSIONS

Blockade of MCP-1 activity significantly reduced inflammatory pleural effusion formation in a CAR model. Together with recent successes in MCP-1 blockade in other effusion formation models, our data strongly support clinical evaluation of MCP-1 antagonists as a novel approach to pleural fluid management.

Rivaroxaban limits complement activation compared with warfarin in antiphospholipid syndrome patients with venous thromboembolism

Essentials Complement activation has a pathogenic role in thrombotic antiphospholipid syndrome (APS). Coagulation proteases such as factor Xa can activate complement proteins. Complement activation markers were elevated in anticoagulated thrombotic APS patients. Complement activation decreased in APS patients switching from warfarin to rivaroxaban.

SUMMARY

Background Complement activation may play a major role in the pathogenesis of thrombotic antiphospholipid syndrome (APS). Coagulation proteases such as factor Xa can activate complement proteins. Aims To establish whether rivaroxaban, a direct factor Xa inhibitor, limits complement activation compared with warfarin in APS patients with previous venous thromboembolism (VTE). Methods A total of 111 APS patients with previous VTE, on warfarin target INR 2.5, had blood samples taken at baseline and at day 42 after randomization in the RAPS (Rivaroxaban in Antiphospholipid Syndrome) trial. Fifty-six patients remained on warfarin and 55 switched to rivaroxaban. Fifty-five normal controls (NC) were also studied. Markers of complement activation (C3a, C5a, terminal complement complex [SC5b-9] and Bb fragment) were assessed. Results APS patients had significantly higher complement activation markers compared with NC at both time-points irrespective of the anticoagulant. There were no differences between the two patient groups at baseline, or patients remaining on warfarin at day 42. In 55 patients randomized to rivaroxaban, C3a, C5a and SC5b-9 were lower at day 42 (median (ng mL-1 ) [confidence interval] 64 [29-125] vs. 83 [35-147], 9 [2-15] vs. 12 [4-18] and 171 [56-245] vs. 201 [66-350], respectively) but levels of Bb fragment were unchanged. There were no correlations between rivaroxaban levels and complement activation markers. Conclusions APS patients with previous VTE on warfarin exhibit increased complement activation, which is likely to occur via the classical pathway and is decreased by rivaroxaban administration. Rivaroxaban may therefore potentially provide an additional benefit to its anticoagulant effect in this patient group by limiting complement activation.

Heparin reduces overcirculation-induced pulmonary artery remodeling through p38 MAPK in piglet

BACKGROUND

Artery remodeling is the principal change of pulmonary artery hypertension. Heparin has been shown to inhibit vascular smooth muscle cell proliferation. We hypothesized that heparin may modulate vascular remodeling in pulmonary artery hypertension, and explored the mechanism.

METHODS

A localized overcirculation-induced artery remodeling was created in piglets by anastomosing the left lower lobe pulmonary artery (LLLPA) to the thoracic aortic artery. Piglets were treated with heparin or saline for 4 weeks. Hemodynamic data were collected, and histology of the lung was assessed. We investigated the expressions of several candidate genes in lung and further observed the involvement of P38 mitogen-activated protein kinases (MAPK). The effects of heparin on the growth of cultured pulmonary arterial vascular smooth muscle cell and P38 MAPK expression were further determined under various conditions.

RESULTS

Four weeks after the shunt setup, overcirculation caused significant LLLPA remodeling, pressure increase, and pulmonary vascular resistance increase, and LLLPA flow reduction compared with that immediately after the shunt setup. Heparin reduced the LLLPA remodeling, pressure, and pulmonary vascular resistance, and increased the LLLPA flow compared with that not heparin treated. Shunt and heparin treatment did not change the piglet's systemic hemodynamics. Shunt increased the expression of P38 MAPK and heparin decreased its expression in the shunted LLLPA. Both heparin and P38 MAPK inhibitor suppressed VSMC growth and P38 MAPK expression in the cultured VSMC, but they did not present additive effects when the two treatments were combined.

CONCLUSIONS

Heparin reduces overcirculation-induced pulmonary artery remodeling through a P38 MAPK-dependent pathway.

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.

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.

Tumor necrosis factor alpha-induced inflammation is increased but apoptosis is inhibited by common food additive carrageenan

Tumor necrosis factor (TNF)-α, a homotrimeric, pleiotropic cytokine, is secreted in response to inflammatory stimuli in diseases such as rheumatoid arthritis and inflammatory bowel disease. TNF-α mediates both apoptosis and inflammation, stimulating an inflammatory cascade through the non-canonical pathway of NF-κB activation, leading to increased nuclear RelB and p52. In contrast, the common food additive carrageenan (CGN) stimulates inflammation through both the canonical and non-canonical pathways of NF-κB activation and utilizes the adaptor molecule BCL10 (B-cell leukemia/lymphoma 10). In a series of experiments, colonic epithelial cells and mouse embryonic fibroblasts were treated with TNF-α and carrageenan in order to simulate the possible effects of exposure to dietary CGN in the setting of a TNF-α-mediated inflammatory disease process. A marked increase in secretion of IL-8 occurred, attributable to synergistic effects on phosphorylated NF-κB-inducing kinase (NIK) in the non-canonical pathway. TNF-α induced the ubiquitination of TRAF2 (TNF receptor-associated factor 2), which interacts with NIK, and CGN induced phosphorylation of BCL10, leading to increased NIK phosphorylation. These results suggest that TNF-α and CGN in combination act to increase NIK phosphorylation, thereby increasing activation of the non-canonical pathway of NF-κB activation. In contrast, the apoptotic effects of TNF-α, including activation of caspase-8 and PARP-1 (poly(ADP-ribose) polymerase 1) fragmentation, were markedly reduced in the presence of CGN, and CGN caused reduced expression of Fas. These findings demonstrate that exposure to CGN drives TNF-α-stimulated cells toward inflammation rather than toward apoptotic cell death and suggest that CGN exposure may compromise the effectiveness of anti-TNF-α therapy.

Heparin: a potent inhibitor of hepcidin expression in vitro and in vivo

Hepcidin is a major regulator of iron homeostasis, and its expression in liver is regulated by iron, inflammation, and erythropoietic activity with mechanisms that involve bone morphogenetic proteins (BMPs) binding their receptors and coreceptors. Here we show that exogenous heparin strongly inhibited hepcidin expression in hepatic HepG2 cells at pharmacologic concentrations, with a mechanism that probably involves bone morphogenetic protein 6 sequestering and the blocking of SMAD signaling. Treatment of mice with pharmacologic doses of heparin inhibited liver hepcidin mRNA expression and SMAD phosphorylation, reduced spleen iron concentration, and increased serum iron. Moreover, we observed a strong reduction of serum hepcidin in 5 patients treated with heparin to prevent deep vein thrombosis, which was accompanied by an increase of serum iron and a reduction of C-reactive protein levels. The data show an unrecognized role for heparin in regulating iron homeostasis and indicate novel approaches to the treatment of iron-restricted iron deficiency anemia.