Antithrombotic and Anticoagulant Activities of a Low Molecular Weight Fucoidan by the Subcutaneous Route

From seaweed to healing: the potential of fucoidan in wound therapy

This bibliometric review examines the current state of research on fucoidan, a sulphated polysaccharide found in brown seaweed species, and its potential for wound healing. The review included 58 studies that investigated fucoidan's effects on wound healing, revealing that it possesses anti-inflammatory and antioxidant properties that could aid in the healing process. Fucoidan was also found to promote cell proliferation, migration, and angiogenesis, essential for wound healing. However, the optimal dosage, treatment duration, safety, and efficacy of fucoidan in various wound types and patient populations still require further investigation. Additionally, advanced wound dressings like hydrogels have garnered significant attention for their potential in wound healing. While this review indicates promise for fucoidan as a natural wound healing compound, it underscores the need for additional clinical trials to determine its optimal use as a commercial therapeutic agent in wound healing.

Sulfation of furcellaran and its effect on hemocompatibility in vitro

In this study, furcellaran (FUR) obtained from Furcellaria lumbricalis was firstly employed for sulfation via various methods, including SO3-pyridine (SO3∙Py) complex in different aprotic solvents, chlorosulfonic acid and sulfuric acid with a "coupling" reagent N,N'-Dicyclohexylcarbodiimide. Structural characterization through FT-IR, GPC, XPS and elemental analyses confirmed the successful synthesis of 6-O-sulfated FUR derivates characterized by varying degrees of sulfation (DS) ranging from 0.15 to 0.91 and molecular weight (Mw) spanning from12.5 kDa to 2.7 kDa. In vitro clotting assays, partial thromboplastin time (aPTT), thrombin time (TT), and prothrombin time (PT) underscored the essential role of sulfate esters in conferring anticoagulant activity whereas FUR prepared via chlorosulfonic acid with DS of 0.91 reached 311.4 s in aPPT showing almost 4-fold higher anticoagulant activity than native FUR at the concentration 2 mg/mL. MTT test showed all tested samples decreased cell viability in a dose dependent manner while all of them are non-cytotoxic up to the concentration of 0.1 mg/mL. Furthermore, sulfated derivates deposited onto polyethylene terephthalate surface presented substantial decrease in platelet adhesion, as well as absence of the most activated platelet stages. These findings support the pivotal role of O-6 FUR sulfates in enhancing hemocompatibility and provide valuable insights for a comparative assessment of effective sulfating approaches.

The Discovery of the Fucoidan-Active Endo-1→4-α-L-Fucanase of the GH168 Family, Which Produces Fucoidan Derivatives with Regular Sulfation and Anticoagulant Activity

Sulfated polysaccharides of brown algae, fucoidans, are known for their anticoagulant properties, similar to animal heparin. Their complex and irregular structure is the main bottleneck in standardization and in defining the relationship between their structure and bioactivity. Fucoidan-active enzymes can be effective tools to overcome these problems. In the present work, we identified the gene fwf5 encoding the fucoidan-active endo-fucanase of the GH168 family in the marine bacterium Wenyingzhuangia fucanilytica CZ1127T. The biochemical characteristics of the recombinant fucanase FWf5 were investigated. Fucanase FWf5 was shown to catalyze the endo-type cleavage of the 1→4-O-glycosidic linkages between 2-O-sulfated α-L-fucose residues in fucoidans composed of the alternating 1→3- and 1→4-linked residues of sulfated α-L-fucose. This is the first report on the endo-1→4-α-L-fucanases (EC 3.2.1.212) of the GH168 family. The endo-fucanase FWf5 was used to selectively produce high- and low-molecular-weight fucoidan derivatives containing either regular alternating 2-O- and 2,4-di-O-sulfation or regular 2-O-sulfation. The polymeric 2,4-di-O-sulfated fucoidan derivative was shown to have significantly greater in vitro anticoagulant properties than 2-O-sulfated derivatives. The results have demonstrated a new type specificity among fucanases of the GH168 family and the prospects of using such enzymes to obtain standard fucoidan preparations with regular sulfation and high anticoagulant properties.

Recent Advances in Marine Biomaterials Tailored and Primed for the Treatment of Damaged Soft Tissues

The inherent self-repair abilities of the body often fall short when it comes to addressing injuries in soft tissues like skin, nerves, and cartilage. Tissue engineering and regenerative medicine have concentrated their research efforts on creating natural biomaterials to overcome this intrinsic healing limitation. This comprehensive review delves into the advancement of such biomaterials using substances and components sourced from marine origins. These marine-derived materials offer a sustainable alternative to traditional mammal-derived sources, harnessing their advantageous biological traits including sustainability, scalability, reduced zoonotic disease risks, and fewer religious restrictions. The use of diverse engineering methodologies, ranging from nanoparticle engineering and decellularization to 3D bioprinting and electrospinning, has been employed to fabricate scaffolds based on marine biomaterials. Additionally, this review assesses the most promising aspects in this field while acknowledging existing constraints and outlining necessary future steps for advancement.

Protective effects of fucoidan against kidney diseases: Pharmacological insights and future perspectives

Chronic kidney disease (CKD) is a major public health concern that costs millions of lives worldwide. Natural products are consistently being explored for the development of novel therapeutics in the management of CKD. Fucoidan is a sulfated polysaccharide predominantly extracted from brown seaweed, which has multiple pharmacological benefits against various kidney problems, including chronic renal failure and diabetic nephropathy. This review aimed at exploring literature to update the renoprotective effects of fucoidan, to get an understanding of pharmacological mechanisms, and to highlight the recent progress of fucoidan-based therapeutic development. Evidence shows that fucoidan is effective against inflammation, oxidative stress, and fibrosis in kidney. Fucoidan targets multiple signaling systems, including Nrf2/HO-1, NF-κB, ERK and p38 MAPK, TGF-β1, SIRT1, and GLP-1R signaling that are known to be associated with CKD pathobiology. Despite these pharmacological prospects, the application of fucoidan is limited by its larger molecular size. Notably, low molecular weight fucoidan has shown therapeutic promise in some recent studies. However, future research is warranted to translate the outcome of preclinical studies into clinical use in kidney patients.

Complexation of europium(III) with exopolysaccharides from a marine bacterium envisaged as luminescent probe in a theranostic approach

Exopolysaccharide (EPS) derivatives, produced by Alteromonas infernus bacterium, showed anti-metastatic properties in osteosarcoma (bone tumor). These EPSs could be employed as new drug delivery systems for therapeutic uses. They may represent a new class of ligands to be combined in a theranostic approach with fluorescent metals, such as Eu(III), to serve as imaging probe. The goal of this work was to investigate the feasibility of such coupling by time-resolved laser-induced fluorescence spectroscopy (TRLFS). Since these EPSs are polyelectrolytes their conformation could affect the complexation properties. Thus, viscosimetric measurements were performed as a function of their concentration as well as the background electrolyte concentration. Polysaccharides conformation exhibited a lower hydrodynamic volume for the highest ionic strengths. The resulting random-coiled conformation could affect the complexation with metal for high concentration but no change was evidenced when increasing europium concentration. Two sites of complexation of Eu(III) were evidenced by TRLFS in heparin, whereas only one site was evidenced in two modified EPSs produced from Alteromonas infernus.

Antiproliferative Properties of Scandium Exopolysaccharide Complexes on Several Cancer Cell Lines

Antimetastatic properties on both murine and human osteosarcoma cell lines (POS-1 and KHOS) have been evidenced using exopolysaccharide (EPS) derivatives, produced by Alteromonas infernus bacterium. These derivatives had no significant effect on the cell cycle neither a pro-apoptotic effect on osteosarcoma cells. Based on this observation, these EPSs could be employed as new drug delivery systems for therapeutic uses. A theranostic approach, i.e., combination of a predictive biomarker with a therapeutic agent, has been developed notably by combining with true pair of theranostic radionuclides, such as scandium ⁴⁷Sc/⁴⁴Sc. However, it is crucial to ensure that, once complexation is done, the biological properties of the vector remain intact, allowing the molecular tropism of the ligand to recognize its molecular target. It is important to assess if the biological properties of EPS evidenced on osteosarcoma cell lines remain when scandium is complexed to the polymers and can be extended to other cancer cell types. Scandium-EPS complexes were thus tested in vitro on human cell lines: MNNG/HOS osteosarcoma, A375 melanoma, A549 lung adenocarcinoma, U251 glioma, MDA231 breast cancer, and Caco2 colon cancer cells. An xCELLigence Real Cell Time Analysis (RTCA) technology assay was used to monitor for 160 h, the proliferation kinetics of the different cell lines. The tested complexes exhibited an anti-proliferative effect, this effect was more effective compared to EPS alone. This increase of the antiproliferative properties was explained by a change in conformation of EPS complexes due to their polyelectrolyte nature that was induced by complexation. Alterations of both growth factor-receptor signaling, and transmembrane protein interactions could be the principal cause of the antiproliferative effect. These results are very promising and reveal that EPS can be coupled to scandium for improving its biological effects and also suggesting that no major structural modification occurs on the ligand.

Marine Exopolysaccharide Complexed With Scandium Aimed as Theranostic Agents

(1) Background: Exopolysaccharide (EPS) derivatives, produced by Alteromonas infernus bacterium, showed anti-metastatic properties. They may represent a new class of ligands to be combined with theranostic radionuclides, such as ⁴⁷Sc/⁴⁴Sc. The goal of this work was to investigate the feasibility of such coupling. (2) Methods: EPSs, as well as heparin used as a drug reference, were characterized in terms of molar mass and dispersity using Asymmetrical Flow Field-Flow Fractionation coupled to Multi-Angle Light Scattering (AF4-MALS). The intrinsic viscosity of EPSs at different ionic strengths were measured in order to establish the conformation. To determine the stability constants of Sc with EPS and heparin, a Free-ion selective radiotracer extraction (FISRE) method has been used. (3) Results: AF4-MALS showed that radical depolymerization produces monodisperse EPSs, suitable for therapeutic use. EPS conformation exhibited a lower hydrodynamic volume for the highest ionic strengths. The resulting random-coiled conformation could affect the complexation with metal for high concentration. The LogK of Sc-EPS complexes have been determined and showing that they are comparable to the Sc-Hep. (4) Conclusions: EPSs are very promising to be coupled with the theranostic pair of scandium for Nuclear Medicine.

Marine oligosaccharides originated from seaweeds: Source, preparation, structure, physiological activity and applications

Marine polysaccharides originated from seaweeds, including agar, alginate, carrageenan, and fucoidan, possess various kinds of physiological activities and have been widely used in food, agricultural and medical areas. However, the application has been greatly limited by their poor solubility and low bioavailability. Thus marine oligosaccharides, as the degradation products of those polysaccharides, have drawn increasing attentions due to their obvious biological activities, good solubility and excellent bioavailability. This review will summarize the recent advances on the source, molecular structure and physiological activity of marine oligosaccharides, emphasizing their application as functional food additives. Furthermore, the relationship between the structure and the physiological activity of marine oligosaccharides is also elucidated and highlighted. The review concludes with an outlook toward potential applications for preparing the functional oligosaccharides in food biotechnology and agriculture fields.

Antithrombotics from the Sea: Polysaccharides and Beyond

Marine organisms exhibit some advantages as a renewable source of potential drugs, far beyond chemotherapics. Particularly, the number of marine natural products with antithrombotic activity has increased in the last few years, and reports show a wide diversity in scaffolds, beyond the polysaccharide framework. While there are several reviews highlighting the anticoagulant and antithrombotic activities of marine-derived sulfated polysaccharides, reports including other molecules are sparse. Therefore, the present paper provides an update of the recent progress in marine-derived sulfated polysaccharides and quotes other scaffolds that are being considered for investigation due to their antithrombotic effect.

Fucoidans inhibit the formation of post-operative abdominal adhesions in a rat model

Purpose

Fibrin clot is essential for post-operative abdominal adhesion formation. Fucoidans, sulfated polysaccharides, inhibit fibrin clot formation. In addition, they inhibit inflammation and fibrosis, which also play important roles in adhesion formation. The purpose of this study was to evaluate fucoidans’ potential for inhibiting post-operative abdominal adhesions and measure their effects on systemic coagulation parameters when administered intraperitoneally (IP).

Methods and materials

Female Sprague Dawley rats were studied. A 2.5x2.5cm full thickness segment of abdominal wall was excised. The skin edges were approximated. This model induces extensive adhesions and allows objective quantitation. Three fucoidans were evaluated- Sigma Fucoidan Crude (SFC), Fucus vesiculosis 95% (Sigma) and, Peridan. One protocol involved continuous infusion into the abdomen from a subcutaneous osmotic pump. Alternatively, boluses of the solutions were injected IP at the end of the operation. Rats were sacrificed a week later. Adhesion extent was scored. Systemic coagulation effects of fucoidans were also evaluated. INR and aPTT were measured following IP injection of the fucoidan solutions and after 7 days of continuous infusion.

Results

Animals given a continuous infusion of either SFC or Peridan yielded adhesion reduction of 80 to 90% from control. Bolus Peridan had no discernable influence on adhesion formation, but a single bolus of SFC caused significant adhesion reductions. Peridan resulted in prompt aPTT elevations which fell to nearly normal by 5 hours. The maximum peak value after SFC injection was seen in 15 hours. The maximal INR elevations were around 2. Measurement of INR and aPTT after a week of continuous infusion of either Peridan or SFC, were always in the normal control range. The third agent, Sigma, frequently yielded intraperitoneal infection found at autopsy.

Conclusions

These findings indicate that selected fucoidans infused intraperitoneally for a week after abdominal operations reduce adhesion extent by up to 90%.

Modification of native fucoidan from Fucus evanescens by recombinant fucoidanase from marine bacteria Formosa algae

Enzymatic depolymerization of fucoidans attracts many researchers due to the opportunity of obtaining standardized fucoidan fragments. Fucoidanase catalyzes the cleavage of fucoidan from Fucus evanescens (FeF) to form low molecular weight products (LMP) and a polymeric fraction (HMP) with 50.8 kDa molecular weight and more than 50% yield. NMR spectroscopy shows that the HMP fraction has regular structure and consists of a repeating fragment [→3)-α-l-Fucp2,4OSO3--(1 → 4)-α-l-Fucp2,4OSO3--(1 → 4)-α-l-Fucp2OSO3--(1→]n. The anticancer effects of FeF fucoidan and its derivative (HMP) were studied in vitro on colon cancer cells HCT-116, HT-29, and DLD-1. The anticancer activity of the HMP fraction was found to be slightly lower than that of the FeF fucoidan. Research and practical applications of the enzyme include modification of native fucoidans for purposes of regular and easier characterized derivatives acquisition.

Effect of Fucoidan on Anterior Cruciate Ligament Transection and Medial Meniscectomy Induced Osteoarthritis in High-Fat Diet-Induced Obese Rats

Osteoarthritis (OA) has become one of the most common disabilities among elders, especially in females. Obesity and mechanical injuries caused by OA are attributed to joint loading, cartilage disintegration, and bone loss, as well as inflammation. Pharmacological and non-pharmacological treatments can be used for OA. Fucoidan possesses several bioactivities such as antitumor, antiviral, anticoagulation, anti-obesity, and immunomodulation. This study aims to investigate the effect of fucoidan in surgery-induced OA on rats with diet-induced obesity. OA was induced by an anterior cruciate ligament transection and a partial medial meniscectomy (ACLT + MMx). The male SD rats were fed with a high-fat diet (HFD) for 4 weeks to induce obesity before causing ACLT + MMx to induce OA. The OA rats were administered with intragastric water or fucoidan in three different concentrations (32 mg/kg, 64 mg/kg, and 320 mg/kg) after the surgeries for 40 days with an HFD. We observed that the swelling in the knee joint was alleviated and the hind paw weight distribution was rectified after feeding them with fucoidan and that there was no significant effect on the weight gain and feed intake. Fucoidan administration indicated no significant variation on the high-density lipoprotein (HDL)-Cholesterol level, but it did indicate reduced plasma triglycerides and low-density lipoprotein (LDL)-Cholesterol levels. In addition, the weight-bearing tests showed an improvement in the fucoidan-treated group. Our results suggested that fucoidan may improve meniscal/ligamentous injury and obesity-induced OA.

A promising oral fucoidan-based antithrombotic nanosystem: Development, activity and safety

Fucoidan-loaded nanoparticles emerge as great candidates to oral anticoagulant therapy, due to increasing of bioavailability and circulation time of this natural anticoagulant. Crosslink between chitosan chains are performed using glutaraldehyde to confer higher gastric pH resistance to nanoparticle matrices. In this work, chitosan-fucoidan nanoparticles, without (NpCF) and with glutaraldehyde crosslink (NpCF 1% and NpCF 2%), were prepared to evaluate their anticoagulant, antithrombotic and hemorrhagic profile. Nanoparticles were characterized by average diameter, polydispersity index, zeta potential, Fourier transform infrared spectroscopy and fucoidan in vitro release. Anticoagulant and antithrombotic activities were determined by in vitro and in vivo models, respectively. Hemorrhagic profile was in vivo evaluated by tail bleeding assay. Preparations showed nanometric and homogeneous average diameters. Zeta potentials of NpCF and NpCF 1% were stable over gastrointestinal pH range, which was confirmed by low fucoidan release in gastric and enteric media. In pH 7.4, NpCF and NpCF 1% demonstrated fucoidan release of 65.5% and 60.6%, respectively, within the first 24 hours. In comparison to fucoidan, NpCF and NpCF 1% showed increased in vitro anticoagulant activity. A significant difference on oral antithrombotic profile of NpCF 1% was found in comparison to fucoidan. Bleeding profile of NpCF and NpCF 1% showed no differences to control group, indicating the safety of these systems. Surprisingly, oral antithrombotic profile of commercially available fucoidan, from Fucus vesiculosus, has not been previously determined, which reveals new possibilities. In this work, significant advances were observed in anticoagulant and antithrombotic profiles of fucoidan through the preparation of NpCF 1%.

Fucoidan and cancer: a multifunctional molecule with anti-tumor potential

There is a wide variety of cancer types yet, all share some common cellular and molecular behaviors. Most of the chemotherapeutic agents used in cancer treatment are designed to target common deregulated mechanisms within cancer cells. Many healthy tissues are also affected by the cytotoxic effects of these chemical agents. Fucoidan, a natural component of brown seaweed, has anti-cancer activity against various cancer types by targeting key apoptotic molecules. It also has beneficial effects as it can protect against toxicity associated with chemotherapeutic agents and radiation. Thus the synergistic effect of fucoidan with current anti-cancer agents is of considerable interest. This review discusses the mechanisms by which fucoidan retards tumor development, eradicates tumor cells and synergizes with anti-cancer chemotherapeutic agents. Challenges to the development of fucoidan as an anti-cancer agent will also be discussed.

Brown seaweed fucoidan: biological activity and apoptosis, growth signaling mechanism in cancer

Seaweeds, being abundant sources of bioactive components have much interest in recent times. The complex polysaccharides from the brown, red and green seaweeds possess broad spectrum therapeutic properties. The sulfated polysaccharides are routinely used in biomedical research and have known biological activities. Fucoidan, a fucose-rich polysaccharide extracted from brown seaweed has various biological functions including anticancer effects. Cellular damage induces growth arrest and tumor suppression by inducing apoptosis, the mechanism of cell death depends on the magnitude of DNA damage following exposure to anticancer agents. Apoptosis is mainly regulated by cell growth signaling molecules. Number of research studies evidenced that fucoidan shown to induce cytotoxicity of various cancer cells, induces apoptosis, and inhibits invasion, metastasis and angiogenesis of cancer cells. There are few articles discussing on fucoidan biological activity but no specific review on cancer and its signaling mechanism. Hence, this review discusses the brown seaweed fucoidan structure and some biological function and role in apoptosis, invasion, metastasis, angiogenesis and growth signal mechanism on cancer.

Fucoidan prevents high-fat diet-induced obesity in animals by suppression of fat accumulation

This study examines the antiobesity effects of fucoidan in an animal model of diet-induced obesity. Mice were fed a standard diet or high-fat diet (HFD) for 5 weeks. After that, the mice were divided into four experimental groups, with 10 mice per group, including a standard diet group, HFD group, HFD containing 1% fucoidan (HFD + FUCO 1%) group and HFD containing 2% fucoidan (HFD + FUCO 2%) group. The fucoidan supplementation group had significantly decreased body-weight gain, food efficiency ratio and relative liver and epididymal fat mass compared with the HFD group. The mice supplemented with fucoidan showed significantly reduced triglyceride, total cholesterol and low-density lipoprotein levels in the plasma. Liver steatosis induced by the HFD improved in the fucoidan-supplemented group. Furthermore, fucoidan affected the down-regulation expression patterns of epididymal adipose tissue genes such as peroxisome proliferator-activated receptor γ, adipose-specific fatty acid binding protein and acetyl CoA carboxylase. Therefore, fucoidan may be considered for use in improving obesity.

Fucoidan is a novel platelet agonist for the C-type lectin-like receptor 2 (CLEC-2)

Fucoidan, a sulfated polysaccharide from Fucus vesiculosus, decreases bleeding time and clotting time in hemophilia, possibly through inhibition of tissue factor pathway inhibitor. However, its effect on platelets and the receptor by which fucoidan induces cellular processes has not been elucidated. In this study, we demonstrate that fucoidan induces platelet activation in a concentration-dependent manner. Fucoidan-induced platelet activation was completely abolished by the pan-Src family kinase (SFK) inhibitor, PP2, or when Syk is inhibited. PP2 abolished phosphorylations of Syk and Phospholipase C-γ2. Fucoidan-induced platelet activation had a lag phase, which is reminiscent of platelet activation by collagen and CLEC-2 receptor agonists. Platelet activation by fucoidan was only slightly inhibited in FcRγ-chain null mice, indicating that fucoidan was not acting primarily through GPVI receptor. On the other hand, fucoidan-induced platelet activation was inhibited in platelet-specific CLEC-2 knock-out murine platelets revealing CLEC-2 as a physiological target of fucoidan. Thus, our data show fucoidan as a novel CLEC-2 receptor agonist that activates platelets through a SFK-dependent signaling pathway. Furthermore, the efficacy of fucoidan in hemophilia raises the possibility that decreased bleeding times could be achieved through activation of platelets.

A comparative study of antithrombotic and antiplatelet activities of different fucoidans from Laminaria japonica

INTRODUCTION

Fucoidans extracted from brown algae represent an intriguing group of natural fucose-enriched sulfated polysaccharide, with excellent anticoagulant, antimetastatic, antiangiogenic and anti-inflammatory activities. In the present study, we compared antithrombotic activities of four fucoidan fractions with different molecular weight and sulfated ester content from Laminaria japonica in an electrical induced arterial thrombosis and their potential mechanism underlying such activity.

RESULTS AND CONCLUSIONS

In vivo middle molecular weight (MMW) fucoidan fractions with molecular weight about 28000 and 35000 exhibited better antithrombotic activity in electrical induced arterial thrombosis than low molecular weight (LMW) fucoidan LF1 and LF2 (Mw 7600 and 3900). Inhibition of arterial thrombosis occurred at dose of 0.1-0.25mg/kg for MMW fucoidans, accompanied with moderate anticoagulant activity and significant decrease of whole blood viscosity and hematocrit. The antithrombotic effects of MMW Fucoidans might be related with promotion of TFPI content and decrease of TXB2 content, without affecting platelet aggregation and 6-keto-PGF1α content in vivo. In contrast, LMW fucoidans showed a correlation among anticoagulant, antiplatelet and antithrombotic effects in vivo. Antithrombotic action of LF1 and LF2 required high dose of 2.5-10mg/kg, concomitantly with anticoagulant activity and specific inhibition of platelet aggregation in vivo. Their antithrombotic effect might be related to their promotion of TFPI and 6-keto-PGF1α, down regulation of TXB2, without affecting hemorheology. These findings suggested that fucoidan fractions with different molecular weight acted on the antithrombotic action by different mechanism. By comparison, highly sulfated fucoidan LF2 with molecular weight of 3900 seemed to be a more suitable choice of antithrombotic drug for its antithrombotic activity accompanied with specific inhibitory activity on platelet aggregation, low anticoagulant activity and low hemorrhagic risk in vivo.

An antithrombotic fucoidan, unlike heparin, does not prolong bleeding time in a murine arterial thrombosis model: a comparative study of Undaria pinnatifida sporophylls and Fucus vesiculosus

The antithrombotic activities and bleeding effects of selected fucoidans (source from either Undaria pinnatifida sporophylls or from Fucus vesiculosus) have been compared with heparin in the ferric chloride-induced arterial thrombus mouse model. Thrombosis was induced by applying 5% ferric chloride for 3 min on the carotid artery region of Balb/c mouse. Five minutes prior to thrombus induction, mice were infused through the tail vein with either saline (control) or polysaccharides. Either fucoidan or heparin was dosed at 0.1, 1.25, 2.5, 5.0, 10, 25, or 50 mg/kg intravenously (i.v.) The carotid blood flow was monitored until more than 60 min post-thrombus induction. Mouse tail transection bleeding time was measured up to 60 min after making a cut in the mouse tail. Both antithrombotic and bleeding effects were observed in a dose-dependent manner for both fucoidans and heparin. Thrombus formation was totally (reflected by Doppler flow meter) inhibited at either 5 or 50 mg/kg of unfractionated Undaria fucoidan or a low-molecular-weight Undaria fucoidan fraction, respectively, without prolonging the time-to-stop bleeding compared with the control (p < 0.01). The total inhibition of thrombus formation was observed for unfractionated Fucus fucoidan at 25 mg/kg where the time-to-stop bleeding was still significantly prolonged, by as much as 8 ± 1.7 min (p < 0.02). In contrast the heparin-treated group showed total inhibition of thrombus formation even at a small dose of 0.8 mg/kg (400 IU) at which bleeding continued until 60 min. In conclusion algal fucoidans are highly antithrombotic without potential haemorrhagic effects compared with heparin in the arterial thrombus model, but this property differs from algal species to species, and from the molecular structure of fucoidans.

Heparin-like entities from marine organisms

Polysaccharides are ubiquitous in animals and plant cells where they play a significant role in a number of physiological situations e.g. hydration, mechanical properties of cell walls and ionic regulation. This review concentrates on heparin-like entities from marine procaryotes and eukaryotes. Carbohydrates from marine prokaryotes offer a significant structural chemodiversity with novel material and biological properties. Cyanobacteria are Gram-negative photosynthetic prokaryotes considered as a rich source of novel molecules, and marine bacteria are a rich source of polysaccharides with novel structures, which may be a good starting point from which to synthesise heparinoid molecules. For example, some sulphated polysaccharides have been isolated from gamma-proteobacteria such as Alteromonas and Pseudoalteromonas sp. In contrast to marine bacteria, all marine algae contain sulphated wall polysaccharides, whereas such polymers are not found in terrestrial plants. In their native form, or after chemical modifications, a range of polysaccharides isolated from marine organisms have been described that have anticoagulant, anti-thrombotic, anti-tumour, anti-proliferative, anti-viral or anti-inflammatory activities.In spite of the enormous potential of sulphated oligosaccharides from marine sources, their technical and pharmaceutical usage is still limited because of the high complexity of these molecules. Thus, the production of tailor-made oligo- and polysaccharidic structures by biocatalysis is also a growing field of interest in biotechnology.

Marine polysaccharides: a source of bioactive molecules for cell therapy and tissue engineering

The therapeutic potential of natural bioactive compounds such as polysaccharides, especially glycosaminoglycans, is now well documented, and this activity combined with natural biodiversity will allow the development of a new generation of therapeutics. Advances in our understanding of the biosynthesis, structure and function of complex glycans from mammalian origin have shown the crucial role of this class of molecules to modulate disease processes and the importance of a deeper knowledge of structure-activity relationships. Marine environment offers a tremendous biodiversity and original polysaccharides have been discovered presenting a great chemical diversity that is largely species specific. The study of the biological properties of the polysaccharides from marine eukaryotes and marine prokaryotes revealed that the polysaccharides from the marine environment could provide a valid alternative to traditional polysaccharides such as glycosaminoglycans. Marine polysaccharides present a real potential for natural product drug discovery and for the delivery of new marine derived products for therapeutic applications.

Anti-inflammatory effects of fucoidan through inhibition of NF-κB, MAPK and Akt activation in lipopolysaccharide-induced BV2 microglia cells

Fucoidan, a sulfated polysaccharide extracted from brown seaweed, displays a wide variety of internal biological activities; however, the cellular and molecular mechanisms underlying fucoidan's anti-inflammatory activity remain poorly understood. In this study, we investigated the inhibitory effects of fucoidan on production of lipopolysaccharide (LPS)-induced pro-inflammatory mediators in BV2 microglia. Our data indicated that fucoidan treatment significantly inhibited excessive production of nitric oxide (NO) and prostaglandin E₂ (PGE₂) in LPS-stimulated BV2 microglia. It also attenuated expression of inducible nitric oxide synthase (iNOS), cyclooxygenase (COX)-2, monocyte chemoattractant protein-1 (MCP-1), and pro-inflammatory cytokines, including interleukin-1β (IL-1β) and tumor necrosis factor (TNF)-α. Moreover, fucoidan exhibited anti-inflammatory properties by suppression of nuclear factor-kappa B (NF-κB) activation and down-regulation of extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK), p38 mitogen-activated protein kinase (MAPK), and AKT pathways. These finding suggest that fucoidan may offer substantial therapeutic potential for treatment of neurodegenerative diseases that are accompanied by microglial activation.

Chemical structures and bioactivities of sulfated polysaccharides from marine algae

Sulfated polysaccharides and their lower molecular weight oligosaccharide derivatives from marine macroalgae have been shown to possess a variety of biological activities. The present paper will review the recent progress in research on the structural chemistry and the bioactivities of these marine algal biomaterials. In particular, it will provide an update on the structural chemistry of the major sulfated polysaccharides synthesized by seaweeds including the galactans (e.g., agarans and carrageenans), ulvans, and fucans. It will then review the recent findings on the anticoagulant/antithrombotic, antiviral, immuno-inflammatory, antilipidemic and antioxidant activities of sulfated polysaccharides and their potential for therapeutic application.

Heparinoids algal and their anticoagulant, hemorrhagic activities and platelet aggregation

Polysaccharides extracted from brown marine algae represent a source of marine compounds with potential applications in medicine. Heparin-like compounds, fucoidans, have been proposed as alternatives to the anticoagulant heparin, which is prepared from mucous membrane of mammals. In this study, the activity of anticoagulant in activated partial thromboplastin time (APTT) and prothrombin time (PT) tests was assessed in the fucoidan (TF), from seaweed Fucus vesiculosus, partially desulfated fucoidans (PDF), desulfated fucoidans (DF) and purified fractions F1, F2 and F3 in acetone. Studies were also conducted to assess these polysaccharides for platelet aggregation and hemorrhagic activity. The APTT test showed high activity at 5 microg (> or = 240s) for TF, F1 and F2 (P<0.001). PT test showed high anticoagulant activity at 50 microg (> or = 120s) for F1 (P<0.001). Fraction F3, with low MW (15.2 kDa) and sulfate content (26.1%), had little effect in these two in vitro tests (P<0.001). These compounds demonstrated a two-phase response to platelet aggregation at 50 microg/mL. However, at a concentration of 0.1 mg/mL, a hypoaggregate profile was observed for all fractions tested (P<0.001). The analysis showed that fucoidans irreversibly induced platelet aggregation in high concentration. These polymers have low hemorrhagic effect when compared to heparin.

Structure, biology, evolution, and medical importance of sulfated fucans and galactans

Sulfated fucans and galactans are strongly anionic polysaccharides found in marine organisms. Their structures vary among species, but their major features are conserved among phyla. Sulfated fucans are found in marine brown algae and echinoderms, whereas sulfated galactans occur in red and green algae, marine angiosperms, tunicates (ascidians), and sea urchins. Polysaccharides with 3-linked, beta-galactose units are highly conserved in some taxonomic groups of marine organisms and show a strong tendency toward 4-sulfation in algae and marine angiosperms, and 2-sulfation in invertebrates. Marine algae mainly express sulfated polysaccharides with complex, heterogeneous structures, whereas marine invertebrates synthesize sulfated fucans and sulfated galactans with regular repetitive structures. These polysaccharides are structural components of the extracellular matrix. Sulfated fucans and galactans are involved in sea urchin fertilization acting as species-specific inducers of the sperm acrosome reaction. Because of this function the structural evolution of sulfated fucans could be a component in the speciation process. The algal and invertebrate polysaccharides are also potent anticoagulant agents of mammalian blood and represent a potential source of compounds for antithrombotic therapies.

Potential effects of a low-molecular-weight fucoidan extracted from brown algae on bone biomaterial osteoconductive properties

In this work, we first tested the influence of low-molecular-weight (LMW) fucoidan extracted from pheophicae cell wall on bidimensional cultured normal human osteoblasts' behaviors. Second, by impregnation procedure with LMW fucoidan of bone biomaterial (Lubboc), we explored in this bone extracellular matrix context its capabilities to support human osteoblastic behavior in 3D culture. In bidimensionnal cultures, we evidenced that LMW fucoidan promotes human osteoblast proliferation and collagen type I expression and favors precocious alkaline phosphatase activity. Furthermore, with LMW fucoidan, von Kossa's staining was positive at 30 days and positive only at 45 days in the absence of LMW fucoidan. In our three-dimensional culture models with the biomaterial pretreated with LMW fucoidan, osteoblasts promptly overgrew the pretreated biomaterial. We also evidenced that osteoblasts increased proliferation with pretreated biomaterial when compared with untreated biomaterial. Osteoblasts secreted osteocalcin and expressed BMP2 receptor on control material as well as with LMW fucoidan impregnated biomaterial. In conclusion, in our experimental conditions, LMW fucoidan stimulated expression of osteoblastic markers differentiation such as alkaline phosphatase activity, collagen type I expression, and mineral deposition; furthermore, cell proliferation was favored. These findings suggest that fucoidan could be clinically useful for bone regeneration and bone substitute design.

Structure, biological activity, and enzymatic transformation of fucoidans from the brown seaweeds

Recent advances in the study of fucoidans, biologically active sulfated alpha-L-fucans of diverse structures and synthesized exclusively by marine organisms, are overviewed. Their structure, biological activity, the products of their enzymatic degradation and the different enzymes of degradation and modification are considered.

Effect of controlled release of fibroblast growth factor-2 from chitosan/fucoidan micro complex-hydrogel onin vitro andin vivo vascularization

We produced a chitosan/fucoidan micro complex-hydrogel as a carrier for controlled release of heparin binding growth factors such as fibroblast growth factor (FGF)-2. Material consisting of a soluble chitosan (CH-LA) mixed with fucoidan yielded a water-insoluble and injectable hydrogel with filamentous particles. In this study, we examined the ability of the chitosan/fucoidan complex-hydrogel to immobilize FGF-2 and to protect its activity, as well as the controlled release of FGF-2 molecules. The chitosan/fucoidan complex-hydrogel has high affinity for FGF-2 (K(d) = 5.4 x 10(-) (9)M). The interaction of FGF-2 with chitosan/fucoidan complex-hydrogel substantially prolonged the biological half-life time of FGF-2. It also protected FGF-2 from inactivation, for example by heat and proteolysis, and enhance FGF-2 activity. When FGF-2-containing complex-hydrogel was subcutaneously injected into the back of mice, significant neovascularization and fibrous tissue formation were induced near the site of injection at 1 week, and the complex-hydrogel was biodegraded and disappeared by 4 weeks. These findings indicate that controlled release of biologically active FGF-2 molecules is caused by both slow diffusion and biodegradation of the complex-hydrogel, and that subsequent induction of vascularization occurs. FGF-2-containing chitosan/fucoidan micro complex-hydrogel is thus useful and convenient for treatment of ischemic disease.

Low Molecular Weight Fucoidan Increases VEGF165-induced Endothelial Cell Migration by Enhancing VEGF165 Binding to VEGFR-2 and NRP1

Therapeutic induction of angiogenesis is a potential treatment for chronic ischemia. Heparan sulfate proteoglycans are known to play an important role by their interactions with proangiogenic growth factors such as vascular endothelial growth factor (VEGF). Low molecular weight fucoidan (LMWF), a sulfated polysaccharide from brown seaweeds that mimic some biological activities of heparin, has been shown recently to promote revascularization in rat critical hindlimb ischemia. In this report, we first used cultured human endothelial cells (ECs) to investigate the possible ability of LMWF to enhance the actions of VEGF(165). Data showed that LMWF greatly enhances EC tube formation in growth factor reduced matrigel. LMWF is a strong enhancer of VEGF(165)-induced EC chemotaxis, but not proliferation. In addition, LMWF has no effect on VEGF(121)-induced EC migration, a VEGF isoform that does not bind to heparan sulfate proteoglycans. Then, with binding studies using (125)I-VEGF(165), we observed that LMWF enhances the binding of VEGF(165) to recombinant VEGFR-2 and Neuropilin-1 (NRP1), but not to VEGFR-1. Surface plasmon resonance analysis showed that LMWF binds with high affinity to VEGF(165) (1.2 nm) and its receptors (5-20 nm), but not to VEGF(121). Pre-injection of LMWF on immobilized receptors shows that VEGF(165) has the highest affinity for VEGFR-2 and NRP1, as compared with VEGFR-1. Overall, the effects of LMWF were much more pronounced than those of LMW heparin. These findings suggested an efficient mechanism of action of LMWF by promoting VEGF(165) binding to VEGFR-2 and NRP1 on ECs that could help in stimulating therapeutic revascularization.

Isolation and culture of a marine bacterium degrading the sulfated fucans from marine brown algae

Fucoidans are matrix polysaccharides from marine brown algae, consisting of an alpha-L-fucose backbone substituted by sulfate-ester groups and masked with ramifications containing other monosaccharide residues. In spite of their interest as biologically active compounds in a number of homologous and heterologous systems, no convenient sources with fucanase activity are available yet for the degradation of the fucalean algae. We here report on the isolation, characterization, and culture conditions of a bacterial strain capable of degrading various brown algal fucoidans. This bacterium, a member of the family Flavobacteriaceae, was shown to secrete fucoidan endo-hydrolase activity. An extracellular enzyme preparation was used to degrade the fucoidan from the brown alga Pelvetia canaliculata. End products included a tetrasaccharide and a hexasaccharide made of the repetition of disaccharidic units consisting of alpha-1-->3-L-fucopyranose-2-sulfate-alpha-1-->4-L-fucopyranose-2,3-disulfate, with the 3-linked residues at the nonreducing end.

Fucoidan a sulfated polysaccharide from brown algae is a potent modulator of connective tissue proteolysis

Fucoidans are sulfated fucosylated polymers from brown algae cell wall that exhibit some heparin/heparan sulfate properties. We previously demonstrated that these polysaccharides were able in vitro to stimulate dermal fibroblast proliferation and extracellular matrix deposition. Here, we investigated the action of a 16kDa fucoidan fraction on parameters involved in connective tissue breakdown. This fucoidan is able to inhibit gelatinase A secretion and stromelysin 1 induction by interleukin-1beta on dermal fibroblasts in culture. Furthermore, we observed that fucoidan increases the rate of association of MMPs with their specific inhibitors namely TIMPs. Using tissue sections of human skin in ex vivo experiments, we evidenced that this polysaccharide was able to minimize human leukocyte elastase activity resulting in the protection of human skin elastic fiber network against the enzymatic proteolysis due to this serine proteinase. These results suggested that fucoidan could be used for treating some inflammatory pathologies in which uncontrolled extracellular matrix degradation takes place.

Heterofucans from Dictyota menstrualis have anticoagulant activity

Fucan is a term used to denote a family of sulfated L-fucose-rich polysaccharides which are present in the extracellular matrix of brown seaweed and in the egg jelly coat of sea urchins. Plant fucans have several biological activities, including anticoagulant and antithrombotic, related to the structural and chemical composition of polysaccharides. We have extracted sulfated polysaccharides from the brown seaweed Dictyota menstrualis by proteolytic digestion, followed by separation into 5 fractions by sequential acetone precipitation. Gel electrophoresis using 0.05 M 1,3-diaminopropane-acetate buffer, pH 9.0, stained with 0.1% toluidine blue, showed the presence of sulfated polysaccharides in all fractions. The chemical analyses demonstrated that all fractions are composed mainly of fucose, xylose, galactose, uronic acid, and sulfate. The anticoagulant activity of these heterofucans was determined by activated partial thromboplastin time (APTT) using citrate normal human plasma. Only the fucans F1.0v and F1.5v showed anticoagulant activity. To prolong the coagulation time to double the baseline value in the APTT, the required concentration of fucan F1.0v (20 g/ml) was only 4.88-fold higher than that of the low molecular weight heparin Clexane (4.1 g/ml), whereas 80 g/ml fucan 1.5 was needed to obtain the same effect. For both fucans this effect was abolished by desulfation. These polymers are composed of fucose, xylose, uronic acid, galactose, and sulfate at molar ratios of 1.0:0.8:0.7:0.8:0.4 and 1.0:0.3:0.4:1.5:1.3, respectively. This is the fist report indicating the presence of a heterofucan with higher anticoagulant activity from brown seaweed.

Low molecular weight fucoidan and heparin enhance the basic fibroblast growth factor-induced tube formation of endothelial cells through heparan sulfate-dependent alpha6 overexpression

Basic fibroblast growth factor (FGF-2) activates its high-affinity receptors (FGFRs) but also acts through interaction with heparan sulfate proteoglycans (HSPG). Exogenous polysaccharides also modulate the angiogenic activity of FGF-2. We investigated the effect and mechanism of action of a low molecular weight fucoidan derivative (LMWF) on tube formation by human endothelial cells. LMWF has a better arterial antithrombotic potential in animals than low molecular weight heparin (LMWH). After stimulation of human umbilical vein endothelial cells (HUVEC) by FGF-2 and LMWF (or LMWH), we observed 1) using flow cytometry, an increase in the amount of the alpha6 integrin subunit; 2) using quantitative reverse transcription-polymerase chain reaction, an increase in alpha6 mRNA (higher with LMWF than with LMWH); and 3) using a Matrigel model, an increase in vascular tube formation (also higher with LMWF than with LMWH). A direct link between alpha6 overexpression and vascular tube formation was confirmed by use of an anti-alpha6 antibody: in its presence, there was no capillary network formation on Matrigel. Unexpectedly, an anti-FGFR blocking antibody had no effect on alpha6 over-expression, whereas stripping off the heparan sulfate with heparitinases abolished overexpression. Overall, our data suggest that FGF-2 stimulates alpha6 over-expression in HUVEC, through HSPG but independently from FGFR, and that LMWF (or LMWH) modulates this interaction. Expression of heparan sulfate proteoglycan increases after ischemic injury. Given its antithrombotic properties and its ability to potentiate tube formation of endothelial cells, LMWF may have to be considered for revascularization of ischemic areas.

Capillary electrophoresis determination of the binding affinity of bioactive sulfated polysaccharides to proteins: study of the binding properties of fucoidan to antithrombin

The interaction of proteins with polysaccharides represents a major and challenging topic in glycobiology, since such complexes mediate fundamental biological mechanisms. An affinity capillary electrophoresis method has been developed to evidence the complex formation and to determine the binding properties between an anticoagulant polysaccharide of marine origin, fucoidan, and a potential target protein, antithrombin. This method is a variant of zonal electrophoresis in the mobility shift format. A fixed amount of protein was injected into a capillary filled with a background electrolyte containing the polysaccharide in varying concentrations. The effective mobility data of the protein were processed according to classical linearization treatments to obtain the binding constant for the polysaccharide/antithrombin complex. The results indicate that fucoidan binds to antithrombin in a 1:1 stoichiometry and with an affinity depending on the molecular weight of the polysaccharide. For heparin, the binding constant obtained similarly is in accordance with the literature. This is the first report showing the implementation of a capillary electrophoresis method contributing to the mechanistic understanding of the biological activities of fucoidan and providing evidence for the complex formation between fucoidan and the protein inhibitor of the coagulation antithrombin.

Low-molecular-weight fucoidan promotes therapeutic revascularization in a rat model of critical hindlimb ischemia

The therapeutic potential of low-molecular-weight (LMW) fucoidan, a sulfated polysaccharide extracted from brown seaweed devoid of direct antithrombin effect, was investigated in vitro and in a model of critical hindlimb ischemia in rat. In vitro results showed that LMW fucoidan enhanced fibroblast growth factor (FGF)-2-induced [(3)H]thymidine incorporation in cultured rat smooth muscle cells. Intravenous injection in rats of LMW fucoidan significantly increased the stromal-derived factor (SDF)-1 level from 1.2 +/- 0.1 to 6.5 +/- 0.35 ng/ml in plasma. The therapeutic effect of LMW fucoidan (5 mg/kg/day), FGF-2 (1 micro g/kg/day), and LMW fucoidan combined with FGF-2 was assessed 14 days after induction of ischemia by 1) clinical evaluation of claudication, 2) tissue blood flow analysis, 3) histoenzymology of muscle metabolic activity, and 4) quantification of capillary density. Both LMW fucoidan and FGF-2 similarly improved residual muscle blood flow (62.5 +/- 6.5 and 64.5 +/- 4.5%, respectively) compared with the control group (42 +/- 3.5%, p < 0.0001). The combination of FGF-2 and LMW fucoidan showed further significant improvement in tissue blood flow (90.5 +/- 3%, p < 0.0001). These results were confirmed by phosphorylase activity, showing muscle regeneration in rats treated with the combination of FGF-2 and LMW fucoidan. Capillary density count increased from 9.6 +/- 0.7 capillaries/muscle section in untreated ischemic controls to 14.3 +/- 0.9 with LMW fucoidan, 14.5 +/- 0.9 with FGF-2, and 19.1 +/- 0.9 in combination (p < 0.001). Thus, LMW fucoidan potentiates FGF-2 activity, mobilizes SDF-1, and facilitates angiogenesis in a rat model. This natural compound could be of interest as an alternative for conventional treatment in critical ischemia.

Low molecular weight fucoidan prevents neointimal hyperplasia in rabbit iliac artery in-stent restenosis model

OBJECTIVE

Smooth muscle cell (SMC) proliferation within the intima is regulated by heparan sulfates. We studied a low molecular weight (LMW) fucoidan (sulfated polysaccharide from brown seaweed) on SMC proliferation in vitro and intimal hyperplasia in vivo.

METHODS AND RESULTS

In vitro study revealed that LMW fucoidan reduces rabbit SMC proliferation and is internalized in SMC perinuclear vesicles. On rabbit iliac arteries perfused in vivo with fluorolabeled LMW fucoidan after angioplasty, the labeling was mainly located on sites of injury. Pharmacokinetic studies showed that LMW fucoidan exhibited in rats an elimination half-life of 56+/-25 minutes (n=8) after intravenous administration and a constant plasma rate for > or =6 hours after intramuscular administration. After stent implantation in their iliac arteries, rabbits were also treated with LMW fucoidan (5 mg/kg IM twice a day). Histomorphometric analysis at day 14 indicated that LMW fucoidan reduced intimal hyperplasia by 59% (1.79+/-0.4 versus 0.73+/-0.2 mm2, P<0.0001) and luminal cross-sectional area narrowing by 58% (0.38+/-0.08 versus 0.16+/-0.04, P<0.0001). Blood samples showed no anticoagulant activity due to LMW fucoidan.

CONCLUSIONS

This natural polysaccharide with high affinity for SMCs and sustained plasma concentration markedly reduced intimal hyperplasia, suggesting its use for the prevention of human in-stent restenosis.