Effect of carboxyl-reduced heparin on the growth inhibition of bovine pulmonary artery smooth muscle cells

Neutralizing the pathological effects of extracellular histones with small polyanions

Extracellular histones in neutrophil extracellular traps (NETs) or in chromatin from injured tissues are highly pathological, particularly when liberated by DNases. We report the development of small polyanions (SPAs) (~0.9–1.4 kDa) that interact electrostatically with histones, neutralizing their pathological effects. In vitro, SPAs inhibited the cytotoxic, platelet-activating and erythrocyte-damaging effects of histones, mechanistic studies revealing that SPAs block disruption of lipid-bilayers by histones. In vivo, SPAs significantly inhibited sepsis, deep-vein thrombosis, and cardiac and tissue-flap models of ischemia-reperfusion injury (IRI), but appeared to differ in their capacity to neutralize NET-bound versus free histones. Analysis of sera from sepsis and cardiac IRI patients supported these differential findings. Further investigations revealed this effect was likely due to the ability of certain SPAs to displace histones from NETs, thus destabilising the structure. Finally, based on our work, a non-toxic SPA that inhibits both NET-bound and free histone mediated pathologies was identified for clinical development.

Histones, proteins that bind DNA, are toxic for pathogens outside cells but can also cause multi-organ damage as seen in sepsis. Here the authors develop small negatively charged molecules that can be used as histone antidotes, and show that they improve the phenotype in mouse models with histone-related pathologies.

Heparinoid Complex-Based Heparin-Binding Cytokines and Cell Delivery Carriers

Heparinoid is the generic term that is used for heparin, heparan sulfate (HS), and heparin-like molecules of animal or plant origin and synthetic derivatives of sulfated polysaccharides. Various biological activities of heparin/HS are attributed to their specific interaction and regulation with various heparin-binding cytokines, antithrombin (AT), and extracellular matrix (ECM) biomolecules. Specific domains with distinct saccharide sequences in heparin/HS mediate these interactions are mediated and require different highly sulfated saccharide sequences with different combinations of sulfated groups. Multivalent and cluster effects of the specific sulfated sequences in heparinoids are also important factors that control their interactions and biological activities. This review provides an overview of heparinoid-based biomaterials that offer novel means of engineering of various heparin-binding cytokine-delivery systems for biomedical applications and it focuses on our original studies on non-anticoagulant heparin-carrying polystyrene (NAC-HCPS) and polyelectrolyte complex-nano/microparticles (N/MPs), in addition to heparin-coating devices.

Bioactive Exopolysaccharides Reveal Camellia oleifera Infected by the Fungus Exobasidium gracile Could Have a Functional Use

Camellia oleifera is an important Chinese commercial crop. Camellia oleifera can display abnormal leaves due to infection by the parasitic fungus Exobasidium gracile. Exobasidium gracile was isolated from infected leaves and used in fermentation, and exopolysaccharides EP0-1 and EP0.5-1 were purified from the fermentation broth. EP0-1 was an alkaline polysaccharide consisting mainly of the linkages α-d-Manp(1→, →2)-α-d-Manp(1→ and →6)-α-d-Manp(1→, →3)-α-d-Glcp(1→ and→4)-α-d-Glcp(1→, terminal β-d-Galf, (1→5)-β-d-Galf, and terminal β-D-GlcN(1→. EP0.5-1 was an acidic galactofuranose-containing polysaccharide. It contained the linkages of α-d-Manp(1→, →2)-α-d-Manp(1→, →6)-α-d-Manp(1→,→2, 6)-α-d-Manp(1→, →4)-α-d-Glcp(1→, and →4)-α-d-GlcUA(1→. Galactofuranose linkages were composed of terminal β-d-Galf, (1→6)-β-d-Galf and (1→2)-β-d-Galf. Exobasidium gracile exopolysaccharides displayed significant immunoregulatory activity by activating macrophages. This research indicates that infected leaves from Camellia oleifera including the exopolysaccharides produced by the parasitic fungus Exobasidium gracile by are worth further investigation as a functional product.

Identification of Heparin Modifications and Polysaccharide Inhibitors of Plasmodium falciparum Merozoite Invasion That Have Potential for Novel Drug Development

Despite recent successful control efforts, malaria remains a leading global health burden. Alarmingly, resistance to current antimalarials is increasing and the development of new drug families is needed to maintain malaria control. Current antimalarials target the intraerythrocytic developmental stage of the Plasmodium falciparum life cycle. However, the invasive extracellular parasite form, the merozoite, is also an attractive target for drug development. We have previously demonstrated that heparin-like molecules, including those with low molecular weights and low anticoagulant activities, are potent and specific inhibitors of merozoite invasion and blood-stage replication. Here we tested a large panel of heparin-like molecules and sulfated polysaccharides together with various modified chemical forms for their inhibitory activity against P. falciparum merozoite invasion. We identified chemical modifications that improve inhibitory activity and identified several additional sulfated polysaccharides with strong inhibitory activity. These studies have important implications for the further development of heparin-like molecules as antimalarial drugs and for understanding merozoite invasion.

Interaction of endothelial and smooth muscle cells with cobalt-chromium alloy surfaces coated with paclitaxel deposited self-assembled monolayers

The use of self-assembled monolayers (SAMs) as a polymer-free platform to deliver an antiproliferative drug, paclitaxel (PAT), from a stent material cobalt-chromium (CoCr) alloy has been previously demonstrated. In this study, the interaction of human aortic endothelial cells (ECs) and human aortic smooth muscle cells (SMCs) with CoCr alloy surfaces coated with SAMs- (SAMs-CoCr) and PAT-deposited SAMs (PAT-SAMs-CoCr) was investigated. A polished CoCr with no coatings was used as a control. The viability, proliferation, morphology, and phenotype of ECs and SMCs were investigated on these samples. SAMs-CoCr significantly enhanced the growth of ECs. Also, the ECs were well spreading with its typical morphological features and showed stronger PECAM-1 expression on SAMs-CoCr. This showed that the SAMs-CoCr surface is conducive to endothelialization. For PAT-SAMs-CoCr, although the adhesion of ECs was lower, the cells continued to proliferate with some degree of spreading and limited PECAM-1 expression. For SMCs, a significant decrease in the cell proliferation was observed on SAMs-CoCr when compared with that of Control-CoCr. PAT-SAMs-CoCr showed maximum inhibitory effect on the proliferation of SMCs. Also, the SMCs on PAT-SAMs-CoCr displayed a poorly spread discoid morphology with disarranged α-actin filaments. This showed that the PAT released from the SAMs platform successfully inhibited the growth of SMCs. Thus, this study showed the interaction of ECs and SMCs with SAMs-CoCr and PAT-SAMs-CoCr for potential uses in stents and other cardiovascular medical devices.

Heparin nanomodification improves biocompatibility and biomechanical stability of decellularized vascular scaffolds

Biocompatibility and biomechanical stability are two of the main obstacles limiting the effectiveness of vascular scaffolds. To improve the biomechanical stability and biocompatibility of these scaffolds, we created a heparin-nanomodified acellular bovine jugular vein scaffold by alternating linkage of heparin and dihydroxy-iron via self-assembly. Features of the scaffold were evaluated in vitro and in vivo. Heparin was firmly linked to and formed nanoscale coatings around the fibers of the scaffold, and the amount of heparin linked was about 808 ± 86 μg/cm² (101 ± 11 USP/cm²) per assembly cycle. The scaffolds showed significantly strengthened biomechanical stability with sustained release of heparin for several weeks in vitro. Importantly, the modified scaffolds showed significantly reduced platelet adhesion, stimulated proliferation of endothelial cells in vitro, and reduced calcification in a subcutaneous implantation rat model in vivo. Heparin nanomodification improves the biocompatibility and biomechanical stability of vascular scaffolds.