ASCA-related antibodies in the blood sera of healthy donors and patients with colorectal cancer: characterization with oligosaccharides related to Saccharomyces cerevisiae mannan.

Mannans are polysaccharide antigens expressed on the cell wall of different fungal species including Saccharomyces cerevisiae and Candida spp. These fungi are components of the normal intestinal microflora, and the presence of antibodies to fungal antigens is known to reflect the features of the patient's immune system. Thus, titers of IgG and IgA antibodies against Saccharomyces cerevisiae mannan (ASCA) are markers for clinical diagnostics of inflammatory bowel diseases. The complex organization and heterogeneity of cell-wall mannans may reduce the quality and reproducibility of ELISA results due to interference by different antigenic epitopes. In this research, we analyzed the levels of IgG antibodies in the sera of healthy donors and patients with colorectal cancer using an array of synthetic oligosaccharides related to distinct fragments of fungal mannan. This study aimed to establish the influence of oligosaccharide structure on their antigenicity. Variations in the structure of the previously established ASCA epitope (changing type of linkage, chain length, and the presence of branches) significantly modified the ability of ligands to bind to circulating antibodies in blood sera. The study showed that surface presentation density of the ligand critically affects the results of enzyme immunoassay. The transition from natural coating antigens to their corresponding synthetic mimetics with a defined structure opens new opportunities for improving existing ELISA test systems, as well as developing diagnostic kits with new properties.

Anti-Cancer Potential of Transiently Transfected HER2-Specific Human Mixed CAR-T and NK Cell Populations in Experimental Models: Initial Studies on Fucosylated Chondroitin Sulfate Usage for Safer Treatment.

Human epidermal growth factor receptor 2 (HER2) is overexpressed in numerous cancer cell types. Therapeutic antibodies and chimeric antigen receptors (CARs) against HER2 were developed to treat human tumors. The major limitation of anti-HER2 CAR-T lymphocyte therapy is attributable to the low HER2 expression in a wide range of normal tissues. Thus, side effects are caused by CAR lymphocyte "on-target off-tumor" reactions. We aimed to develop safer HER2-targeting CAR-based therapy. CAR constructs against HER2 tumor-associated antigen (TAA) for transient expression were delivered into target T and natural killer (NK) cells by an effective and safe non-viral transfection method via nucleofection, excluding the risk of mutations associated with viral transduction. Different in vitro end-point and real-time assays of the CAR lymphocyte antitumor cytotoxicity and in vivo human HER2-positive tumor xenograft mice model proved potent cytotoxic activity of the generated CAR-T-NK cells. Our data suggest transient expression of anti-HER2 CARs in plasmid vectors by human lymphocytes as a safer treatment for HER2-positive human cancers. We also conducted preliminary investigations to elucidate if fucosylated chondroitin sulfate may be used as a possible agent to decrease excessive cytokine production without negative impact on the CAR lymphocyte antitumor effect.

Neopetroside-B alleviates doxorubicin-induced cardiotoxicity via mitochondrial protection.

Doxorubicin, a member of the anthracycline family, is a widely prescribed anticancer chemotherapy drug. Unfortunately, cumulative doses of doxorubicin can cause mitochondrial dysfunction, leading to acute or chronic cardiotoxicity. This study demonstrated that Neopetroside-B (NPS-B) protects cardiomyocytes in the presence of doxorubicin. NPS-B improved mitochondrial function in cardiomyocytes by increasing ATP production and oxygen consumption rates. On the other hand, NPS-B negatively influenced cancer cell lines by increasing reactive oxygen species. We analyzed NPS-B-influenced metabolites (VIP > 1.0; AUC>0.7; p < 0.05) and proteins (FC > 2.0) and constructed metabolite-protein enrichment, which showed that NPS-B affected uracil metabolism and NAD-binding proteins (e.g., aldehyde dehydrogenase and glutathione reductase) in cardiomyocytes. However, for the cancer cells, NPS-B decreased the NAD+/NADH balance, impairing cell viability. In a xenograft mouse model treated with doxorubicin, NPS-B reduced cardiac fibrosis and improved cardiac function. NPS-B may be a beneficial intervention to reducing doxorubicin-induced cardiotoxicity with anticancer effects.

Perspectives for the Use of Fucoidans in Clinical Oncology.

Fucoidans are natural sulfated polysaccharides that have a wide range of biological functions and are regarded as promising antitumor agents. The activity of various fucoidans and their derivatives has been demonstrated in vitro on tumor cells of different histogenesis and in experiments on mice with grafted tumors. However, these experimental models showed low levels of antitumor activity and clinical trials did not prove that this class of compounds could serve as antitumor drugs. Nevertheless, the anti-inflammatory, antiangiogenic, immunostimulating, and anticoagulant properties of fucoidans, as well as their ability to stimulate hematopoiesis during cytostatic-based antitumor therapy, suggest that effective fucoidan-based drugs could be designed for the supportive care and symptomatic therapy of cancer patients. The use of fucoidans in cancer patients after chemotherapy and radiation therapy might promote the rapid improvement of hematopoiesis, while their anti-inflammatory, immunomodulatory, and anticoagulant effects have the potential to improve the quality of life of patients with advanced cancer.

Novel GSK-3ß Inhibitor Neopetroside A Protects Against Murine Myocardial Ischemia/Reperfusion Injury.

Recent trends suggest novel natural compounds as promising treatments for cardiovascular disease. The authors examined how neopetroside A, a natural pyridine nucleoside containing an α-glycoside bond, regulates mitochondrial metabolism and heart function and investigated its cardioprotective role against ischemia/reperfusion injury. Neopetroside A treatment maintained cardiac hemodynamic status and mitochondrial respiration capacity and significantly prevented cardiac fibrosis in murine models. These effects can be attributed to preserved cellular and mitochondrial function caused by the inhibition of glycogen synthase kinase-3 beta, which regulates the ratio of nicotinamide adenine dinucleotide to nicotinamide adenine dinucleotide, reduced, through activation of the nuclear factor erythroid 2-related factor 2/NAD(P)H quinone oxidoreductase 1 axis in a phosphorylation-independent manner.

Antiaggregant effects of (1,2,5-oxadiazolyl)azasydnone ring assemblies as novel antiplatelet agents.

A series of biheterocyclic assemblies comprising of 1,2,5-oxadiazole and azasydnone scaffolds were synthesized and biologically evaluated as novel nitric oxide (NO)-donor and antiplatelet agents. Depending on functional substituents at the biheterocyclic core, all studied compounds demonstrated good NO-donor profiles releasing NO in a wide range of concentrations (19.2%-195.1%) according to a Griess assay. (1,2,5-Oxadiazolyl)azasydnones showed excellent antiplatelet activity in the case of ADP and adrenaline used as inducers completely suppressing the aggregate formation even at the lowest test concentration of 0.0375 µmol/ml, which is a rather unique feature. Moreover, studied biheterocycles possess a selective mechanism of inhibition of platelet aggregation mediated only by ADP and adrenaline, which are considered to be the main inducers causing thrombus formation. In addition, (1,2,5-oxadiazolyl)azasydnones were found to be completely non-toxic to hybrid endothelial cells EaHy 926. Studies of hydrolytic degradation of the synthesized compounds afforded benzoic acid as a sole detectable decomposition product, which is considered advantageous in drug design. Therefore, (1,2,5-oxadiazolyl)azasydnones represent a novel class of promising drug candidates with improved antiplatelet profile and reduced toxicity enabling their huge potential in medicinal chemistry and drug design.

Chondroitin Sulfate and Fucosylated Chondroitin Sulfate as Stimulators of Hematopoiesis in Cyclophosphamide-Induced Mice.

The immunosuppression and inhibition of hematopoiesis are considered to be reasons for the development of complications after intensive chemotherapy and allogeneic hematopoietic stem cell transplantation. Chondroitin sulfate (CS), isolated from the fish Salmo salar, and fucosylated chondroitin sulfate (FCS), isolated from the sea cucumber Apostichopus japonicus, were studied for their roles as stimulators of hematopoiesis in a model of cyclophosphamide-induced immunosuppression in mice. The recombinant protein r G-CSF was applied as a reference. The studied polysaccharides were shown to stimulate the release of white and red blood cells, as well as platelets from bone marrow in immunosuppressed mice, while r G-CSF was only responsible for the significant increase in the level of leucocytes. The analysis of different populations of leucocytes in blood indicated that r G-CSF mainly stimulated the production of neutrophils, whereas in the cases of the studied saccharides, increases in the levels of monocytes, lymphocytes and neutrophils were observed. The normalization of the level of the pro-inflammatory cytokine IL-6 in the serum and the recovery of cell populations in the spleen were observed in immunosuppressed mice following treatment with the polysaccharides. An increase in the proliferative activity of hematopoietic cells CD34(+)CD45(+) was observed following ex vivo polysaccharide exposure. Further study on related oligosaccharides regarding their potential as promising drugs in the complex prophylaxis and therapy of hematopoiesis inhibition after intensive chemotherapy and allogeneic hematopoietic stem cell transplantation seems to be warranted.

Synthesis of Biotin-Tagged Chitosan Oligosaccharides and Assessment of Their Immunomodulatory Activity.

Chitin, a polymer of ß-(1→4)-linked N-acetyl-d-glucosamine, is one of the main polysaccharide components of the fungal cell wall. Its N-deacetylated form, chitosan, is enzymatically produced in the cell wall by chitin deacetylases. It exerts immunomodulative, anti-inflammatory, anti-cancer, anti-bacterial, and anti-fungal activities with various medical applications. To study the immunobiological properties of chitosan oligosaccharides, we synthesized a series of ß-(1→4)-linked N-acetyl-d-glucosamine oligomers comprising 3, 5, and 7 monosaccharide units equipped with biotin tags. The key synthetic intermediate employed for oligosaccharide chain elongation, a disaccharide thioglycoside, was prepared by orthogonal glycosylation of a 4-OH thioglycoside acceptor with a glycosyl trichloroacetimidate bearing the temporary 4-O-tert-butyldimethylsilyl group. The use of silyl protection suppressed aglycon transfer and provided a high yield for the target disaccharide donor. Using synthesized chitosan oligomers, as well as previously obtained chitin counterparts, the immunobiological relationship between these synthetic oligosaccharides and RAW 264.7 cells was studied in vitro. Evaluation of cell proliferation, phagocytosis, respiratory burst, and Th1, Th2, Th17, and Treg polarized cytokine expression demonstrated effective immune responsiveness and immunomodulation in RAW 264.7 cells exposed to chitin- and chitosan-derived oligosaccharides. Macrophage reactivity was accompanied by significant inductive dose- and structure-dependent protective Th1 and Th17 polarization, which was greater with exposure to chitosan- rather than chitin-derived oligosaccharides. Moreover, no antiproliferative or cytotoxic effects were observed, even following prolonged 48 h exposure. The obtained results demonstrate the potent immunobiological activity of these synthetically prepared chito-oligosaccharides.

Fucosylated chondroitin sulfate from the sea cucumber Hemioedema spectabilis: Structure and influence on cell adhesion and tubulogenesis.

Fucosylated chondroitin sulfate (FCS) HeSp was isolated from the Patagonian sea cucumber Hemioedema spectabilis. Ion-exchange chromatography was applied for purification of the FCS from the crude extract of sulfated polysaccharides. Analysis of monosaccharide and sulfate content of HeSp revealed the molar ratio of GlcA:GalNAc:Fuc:SO3Na as 1.15:1:1.1:3.9. Molecular weight of HeSp (44.1 kDa) was determined by GPC. According to the NMR spectral data, the main fragment of HeSp was the trisaccharide →3)-ß-d-GalNAc-(1→4)-ß-d-GlcA(3-O-α-l-Fuc)-(1→, where GalNAc units were sulfated either at O-4, at O-6 or both at O-4 and O-6. The fucosyl branches attached to O-3 of GlcA showed also different patterns of sulfation: Fucp2S4S, Fucp4S and Fucp3S4S were found in a ratio of 3.8:1.5:1. Besides, small amounts of the disaccharide fragment →3)-ß-d-GalNAc-(1→4)-ß-d-GlcA3S-(1→ were observed in a structure of HeSp. The polysaccharide was found to block cancer cells adhesion to platelet-coated surface and to inhibit tubulogenesis, thus demonstrating the potential antitumor activity.

Importance of Candida Antigenic Factors: Structure-Driven Immunomodulation Properties of Synthetically Prepared Mannooligosaccharides in RAW264.7 Macrophages.

The incidence and prevalence of serious fungal infections is rising, especially in immunosuppressed individuals. Moreover, co-administration of antibiotics and immunosuppressants has driven the emergence of new multidrug-resistant pathogens. The significant increase of multidrug-resistant pathogens, together with their ability to form biofilms, is associated with morbidity and mortality. Research on novel synthetically prepared immunomodulators as potential antifungal immunotherapeutics is of serious interest. Our study demonstrated the immunobiological activity of synthetically prepared biotinylated mannooligosaccharides mimicking Candida antigenic factors using RAW264.7 macrophages. Macrophage exposure to the set of eight structurally different mannooligosaccharides induced a release of Th1, Th2, Th17, and Treg cytokine signature patterns. The observed immune responses were tightly associated with structure, dose, exposure time, and selected signature cytokines. The viability/cytotoxicity of the mannooligosaccharide formulas was assessed based on cell proliferation. The structure-based immunomodulatory activity of the formulas was evaluated with respect to the length, branching and conformation of the various formulas. Glycoconjugate formulas with terminal ß-mannosyl-units tended to be more potent in terms of Candida relevant cytokines IL-12 p70, IL-17, GM-CSF, IL-6, and TNFα induction and cell proliferation, and this tendency was associated with structural differences between the studied glycoconjugate formulas. The eight tested mannooligosaccharide conjugates can be considered potential in vitro immunomodulative agents suitable for in vitro Candida diagnostics or prospectively for subcellular anti-Candida vaccine design.

Gas-Phase Fragmentation of Cyclic Oligosaccharides in Tandem Mass Spectrometry.

Modern mass spectrometry, including electrospray and MALDI, is applied for analysis and structure elucidation of carbohydrates. Cyclic oligosaccharides isolated from different sources (bacteria and plants) have been known for decades and some of them (cyclodextrins and their derivatives) are widely used in drug design, as food additives, in the construction of nanomaterials, etc. The peculiarities of the first- and second-order mass spectra of cyclic oligosaccharides (natural, synthetic and their derivatives and modifications: cyclodextrins, cycloglucans, cyclofructans, cyclooligoglucosamines, etc.) are discussed in this minireview.

A sulfated galactofucan from the brown alga Hormophysa cuneiformis (Fucales, Sargassaceae).

The brown alga Hormophysa cuneiformis collected from the coastal waters of Vietnam was used to isolate a mixture of sulfated polysaccharides FHC, which was fractionated further by anion-exchange chromatography on DEAE-Sephacel. The main fraction F3 eluted with 1.5 M NaCl contained essentially l-fucose, d-galactose and sulfate and has very complex NMR spectra. Desulfation to obtain F3deS followed by Smith degradation to obtain F3deS-Sm was used to simplify the structure of F3, and all these preparations were characterized by methylation analysis and NMR spectra. A linear (1 → 3)-linked backbone built up of α-l-fucopyranose residues was identified as the main structural motif of molecules. Some fucose residues attached to position 4 of its 3-linked neighbor were found as branches. Galactose residues having both α- and ß-configurations were found mostly at the periphery of molecules. They are present as (1 → 6)-linked disaccharide of two ß-d-Galp attached to position 4 of the backbone or as single α-d-Galp attached to the same position. Sulfate groups in F3 may probably occupy any positions of the molecule. F3 acts as anticoagulant and is about half as active as the standard low-molecular mass heparin (enoxaparin). FHC was practically inactive in cytotoxicity test against six human cancer cell lines.

Influence of Modified Fucoidan and Related Sulfated Oligosaccharides on Hematopoiesis in Cyclophosphamide-Induced Mice.

Immunosuppression derived after cytostatics application in cancer chemotherapy is considered as an adverse side effect that leads to deterioration of quality of life and risk of infectious diseases. A linear sulfated (1→3)-α-l-fucan M-Fuc prepared by chemical modification of a fucoidan isolated from the brown seaweed Chordaria flagelliformis, along with two structurally related synthetic sulfated oligosaccharides, were studied as stimulators of hematopoiesis on a model of cyclophosphamide immunosuppression in mice. Recombinant granulocyte colony-stimulating factor (r G-CSF), which is currently applied in medicine to treat low blood neutrophils, was used as a reference. Polysaccharide M-Fuc and sulfated difucoside DS did not demonstrate significant effect, while sulfated octasaccharide OS showed higher activity than r G-CSF, causing pronounced neutropoiesis stimulation. In addition, production of erythrocytes and platelets was enhanced after the octasaccharide administration. The assessment of populations of cells in blood and bone marrow of mice revealed the difference in mechanisms of action of OS and r G-CSF.

Evidence for Inhibition of Lysozyme Amyloid Fibrillization by Peptide Fragments from Human Lysozyme: A Combined Spectroscopy, Microscopy, and Docking Study.

Degenerative diseases, such as Alzheimer's and prion diseases, as well as type II diabetes, have a pathogenesis associated with protein misfolding, which routes with amyloid formation. Recent strategies for designing small-molecule and polypeptide antiamyloid inhibitors are mainly based on mature fibril structures containing cross ß-sheet structures. In the present study, we have tackled the hypothesis that the rational design of antiamyloid agents that can target native proteins might offer advantageous prospect to design effective therapeutics. Lysozyme amyloid fibrillization was treated with three different peptide fragments derived from lysozyme protein sequence R(107)-R(115). Using low-resolution spectroscopic, high-resolution NMR, and STD NMR-restrained docking methods such as HADDOCK, we have found that these peptide fragments have the capability to affect lysozyme fibril formation. The present study implicates the prospect that these peptides can also be tested against other amyloid-prone proteins to develop novel therapeutic agents.

Hemorheological effects of secoisolariciresinol in ovariectomized rats.

BACKGROUND: Postmenopausal women often develop hemorheological disorders which may affect the systemic blood circulation and present a cardiovascular risk factor. OBJECTIVE: We evaluated effects of secoisolariciresinol (SECO), a phytoestrogen, on hemorheological parameters and lipid peroxidation in a model of the age-related and/or surgical menopause induced by ovariectomy in rats. METHODS: Arterial blood was sampled from sham-operated female rats, ovariectomized rats (OVX), and OVX treated with SECO (OVXSECO) (20 mg/kg/day intragastrically for two weeks). Plasma estrogen concentration and the following hemorheological parameters were measured: RBC aggregation (half-time of aggregation, T1/2; amplitude of aggregation, AMP; aggregation index, AI), RBC deformability (elongation index, EI), whole blood viscosity at the shear rate of 3-300 s-1, plasma viscosity, hematocrit, plasma fibrinogen. Lipid peroxidation was evaluated by measuring conjugated dienes (CD) and thiobarbituric acid reactive substances (TBARS) in plasma. RESULTS: Ovariectomy in rats caused a 60% decrease in plasma estrogen level and triggered the development of macro- and microhemorheological abnormalities. Blood viscosity increased by 12-31%, RBC elongation index reduced by 16-28%, and T1/2 and AI increased by 35% and 29% respectively. The increase in blood viscosity correlated predominantly with reduced RBC deformability. Plasma CD and TBARS were elevated by 47% and 104% respectively. SECO therapy for OVX rats reduced blood viscosity by 9-18% and T1/2 by 32%, and increased EI by 4-17%. SECO therapy disrupted the correlation between blood viscosity and RBC deformability. Lipid peroxidation was significantly inhibited, as shown by the reduction in CD and TBARS plasma concentrations by 89% and 70% respectively. SECO did not affect plasma viscosity, estrogen or fibrinogen levels. CONCLUSIONS: SECO treatment for OVX rats improves blood macro- and microrheological parameters, possibly through antioxidant protection of RBC.

Structure and biological activity of a fucosylated chondroitin sulfate from the sea cucumber Cucumaria japonica.

A fucosylated chondroitin sulfate (FCS) was isolated from the body wall of Pacific sea cucumber Cucumaria japonicaby extraction in the presence of papain followed by Cetavlon precipitation and anion-exchange chromatography. FCS was shown to contain D-GalNAc, D-GlcA, L-Fuc and sulfate in molar proportions of about 1:1:1:4.5. Structure of FCS was elucidated using NMR spectroscopy and methylation analysis of the native polysaccharide and products of its desulfation and carboxyl reduction. The polysaccharide was shown to contain a typical chondroitin core → 3)-ß-D-GalNAc-(1 → 4)-ß-D-GlcA-(1 →. Sulfate groups in this core occupy O-4 and the majority of O-6 of GalNAc. Fucosyl branches are represented by 3,4- and 2,4-disulfated units in a ratio of 4:1 and are linked to O-3 of GlcA. In addition, ∼ 33% of GlcA are 3-O-sulfated, and hence, the presence of short fucooligosaccharide chains side by side with monofucosyl branches cannot be excluded. FCS was shown to inhibit platelets aggregation in vitro mediated by collagen and ristocetin, but not adenosine diphosphate, and demonstrated significant anticoagulant activity, which is connected with its ability to enhance inhibition of thrombin and factor Xa by antithrombin III, as well as to influence von Willebrand factor activity. The latest property significantly distinguished FCS from low-molecular-weight heparin.

Trimodal Control of Ion-Transport Activity on Cyclo-oligo-(1→6)-ß-D-glucosamine-Based Artificial Ion-Transport Systems.

Cyclo-oligo-(1→6)-ß-D-glucosamines functionalized with hydrophobic tails are reported as a new class of transmembrane ion-transport system. These macrocycles with hydrophilic cavities were introduced as an alternative to cyclodextrins, which are supramolecular systems with hydrophobic cavities. The transport activities of these glycoconjugates were manipulated by altering the oligomericity of the macrocycles, as well as the length and number of attached tails. Hydrophobic tails of 3 different sizes were synthesized and coupled with each glucosamine scaffold through the amide linkage to obtain 18 derivatives. The ion-transport activity increased from di- to tetrameric glucosamine macrocycles, but decreased further when flexible pentameric glucosamine was introduced. The ion-transport activity also increased with increasing length of attached linkers. For a fixed length of linkers, the transport activity decreased when the number of such tails was reduced. All glycoconjugates displayed a uniform anion-selectivity sequence: Cl(-) >Br(-) >I(-) . From theoretical studies, hydrogen bonding between the macrocycle backbone and the anion bridged through water molecules was observed.

Pyridine Nucleosides Neopetrosides A and B from a Marine Neopetrosia sp. Sponge. Synthesis of Neopetroside A and Its ß-Riboside Analogue.

Neopetrosides A (1) and B (2), new naturally occurring ribosides of nicotinic acid with extremely rare α-N-glycoside linkages and residues of p-hydroxybenzoic and pyrrole-2-carboxylic acids attached to C-5', were isolated from a marine Neopetrosia sp. sponge. Structures 1 and 2 were determined by NMR and MS methods and confirmed by the synthesis of 1 and its ß-riboside analogue (3). Neopetroside A (1) upregulates mitochondrial functions in cardiomyocytes.

Conformational analysis of the oligosaccharides related to side chains of holothurian fucosylated chondroitin sulfates.

Anionic polysaccharides fucosylated chondroitin sulfates (FCS) from holothurian species were shown to affect various biological processes, such as metastasis, angiogenesis, clot formation, thrombosis, inflammation, and some others. To understand the mechanism of FCSs action, knowledge about their spatial arrangement is required. We have started the systematic synthesis, conformational analysis, and study of biological activity of the oligosaccharides related to various fragments of these types of natural polysaccharides. In this communication, five molecules representing distinct structural fragments of chondroitin sulfate have been studied by means of molecular modeling and NMR. These are three disaccharides and two trisaccharides containing fucose and glucuronic acid residues with one sulfate group per each fucose residue or without it. Long-range C-H coupling constants were used for the verification of the theoretical models. The presence of two conformers for both linkage types was revealed. For the Fuc-GlA linkage, the dominant conformer was the same as described previously in a literature as the molecular dynamics (MD) average in a dodechasaccharide FCS fragment representing the backbone chain of the polysaccharide including GalNAc residues. This shows that the studied oligosaccharides, in addition to larger ones, may be considered as reliable models for Quantitative Structure-Activity Relationship (QSAR) studies to reveal pharmacophore fragments of FCS.

Fucoidans: pro- or antiangiogenic agents?

Sulfated polysaccharides of brown algae (fucoidans) attract great attention due to their high and strongly diversified biological activity. This review summarizes recent data on the structural variability of these polysaccharides and reports their anti- and proangiogenic properties. Recent publications have revealed that fucoidans isolated from different algal species may differ considerably in the structures of their backbones and branches, in both monosaccharide composition and sulfate content. It was found that the degree of sulfation significantly influences the biological properties of fucoidans. Additionally, fucoidan action in angiogenesis is highly dependent on molecular weight: antiangiogenic activity is connected with the high-molecular weight of polysaccharide molecules, whereas the low-molecular-weight fractions may act as proangiogenic agents. The influence of other fine structural details of fucoidans on angiogenesis remains to be established.