Low molecular weight fucoidan ameliorates hindlimb ischemic injury in type 2 diabetic rats

Fucoidan as a Promising Drug for Pain Treatment: Systematic Review and Meta-Analysis

Fucoidan is a polymer of L-fucose and L-fucose-4-sulphate naturally found in marine sources that inhibits p-selectin, preventing neutrophil recruitment to the site of injury. Fucoidan is employed in many studies as a tool to investigate the contribution of neutrophils to pain, showing analgesic effects. We performed a systematic review and meta-analysis to quantify the analgesic effects of pretreatment with fucoidan reported in the available preclinical studies. In addition, we summarized the articles which have studied the therapeutic effects of fucoidan in pathological pain at preclinical and clinical levels. The results of this systematic review reveal that pretreatment with fucoidan is a powerful tool which reduces neutrophil infiltration by 70-90% at early time points. This meta-analysis showed that preventative treatment with fucoidan produced a significant pain reduction. In addition, several preclinical studies have observed that fucoidan treatment reduces the pain that is associated with various pathologies. Finally, fucoidan has also been tested in several clinical trials, with some degree of analgesic efficacy, but they were mostly small pilot studies. Considering all the above information, it can be concluded that fucoidan is not only a preclinical tool for studying the role of neutrophils in pain but also a promising therapeutic strategy for pain treatment.

Preparation of a Dual-Functional Sulfated Galactofucan Polysaccharide/Poly(vinyl alcohol) Hydrogel to Promote Macrophage Recruitment and Angiogenic Potential in Diabetic Wound Healing

A diabetic foot ulcer is a common high-risk complication in diabetic patients, but there is still no universal dressing for clinical treatment. In this study, a novel dual-functional sulfated galactofucan polysaccharide/poly(vinyl alcohol) hydrogel (DPH20) is developed during freeze-thaw cycles. Experimental results indicated that DPH20 had a high specific surface area, a dense porous structure, and a good swelling property, which could effectively adsorb the exudates and keep the wound moist. Furthermore, DPH20 exhibited remarkably recruited macrophage capability and accelerated the inflammation stage by improving the expression of the mRNA of CCL2, CCR2, and CCL22 in macrophages. DPH20 could promote cell migration and growth factor release to accelerate tube formation under hyperglycemic conditions in cell models of L929s and HUEVCs, respectively. Significantly, DPH20 accelerates the reconstruction of the full-thickness skin wound by accelerating the recruitment of macrophages, promoting angiogenesis, and releasing the growth factor in the diabetic mouse model. Collectively, DPH20 is a promising multifunctional dressing to reshape the damaged tissue environment and accelerate wound healing. This study provides an efficient strategy to repair and regenerate diabetic skin ulcers.

Fucoidan, a brown seaweed polysaccharide in nanodrug delivery

Fucoidan-a sulfated marine seaweed obtained from brown algae-has raised considerable interest in the scientific community over the last decade as it possesses a wide range of biological activities such as antioxidant, antiviral, anti-inflammatory, anticoagulant, antithrombotic, anticarcinogenic, and immunoregulatory. This polysaccharide finds application as a drug delivery vehicle due to its non-cytotoxicity, biocompatibility, and biodegradability. Besides, nano biomedical systems have used this marine alga for diagnostic and therapeutic purposes. Fucoidan has been extensively studied for use in regenerative medicines, in wound healing, and for sustained drug delivery due to its large biodiversity, cost-effectiveness, and mild procedures for extraction and purification. However, the main concern that limits its application is the variance in its batch-to-batch extraction owing to species type, harvesting, and climatic factors. The current review encloses a compendious overview of the origin, chemical structure, and physicochemical and biological properties of fucoidan and its significant role in nanodrug delivery systems. Special emphasis is given to the recent advances in the use of native/modified fucoidan, its combination with chitosan and metal ions for nanodrug delivery applications, especially in cancer treatment. Additionally, use of fucoidan in human clinical trials as a complementary therapeutic agent is also reviewed.

Fucoidan and topography modification improved in situ endothelialization on acellular synthetic vascular grafts

Thrombogenesis remains the primary failure of synthetic vascular grafts. Endothelial coverage is crucial to provide an antithrombogenic surface. However, most synthetic materials do not support cell adhesion, and transanastomotic endothelial migration is limited. Here, a surface modification strategy using fucoidan and topography was developed to enable fast in situ endothelialization of polyvinyl alcohol, which is not endothelial cell-adhesive. Among three different immobilization approaches compared, conjugation of aminated-fucoidan promoted endothelial monolayer formation while minimizing thrombogenicity in both in vitro platelet rich plasma testing and ex vivo non-human primate shunt assay. Screening of six topographical patterns showed that 2 μm gratings increased endothelial cell migration without inducing inflammation responses of endothelial cells. Mechanistic studies demonstrated that fucoidan could attract fibronectin, enabling integrin binding and focal adhesion formation and activating focal adhesion kinase (FAK) signaling, and 2 μm gratings further enhanced FAK-mediated cell migration. In a clinically relevant rabbit carotid artery end-to-side anastomosis model, 60% in situ endothelialization was observed throughout the entire lumen of 1.7 mm inner diameter modified grafts, compared to 0% of unmodified graft, and the four-week graft patency also increased. This work presents a promising strategy to stimulate in situ endothelialization on synthetic materials for improving long-term performance.

Effects of sulfated polysaccharides from Laminaria japonica on regularating the gut microbiotan and alleviating intestinal inflammation in obese mice

Due to their known health-enhancing properties, Laminaria japonica polysaccharides (LJP) may alleviate obesity via unknown mechanisms. This study aimed to investigate beneficial LJP effects and mechanism(s) of action using an animal obesity model (ICR mice fed a high-fat diet). First, LJP were confirmed to consist of sulfated polysaccharides via infrared spectroscopy. Next, LJP administration to mice was found to induce weight loss, reduce liver fat accumulation, and support healthy obesity-related blood serum indicator levels. Notably, LJP treatment significantly reduced TC and LDL levels and significantly increased HDL, LPL, UCP-2, and PPAR-α levels. Furthermore, examinations of tissues of LJP-treated mice revealed significantly reduced intestinal tissue inflammation as compared to corresponding results obtained for untreated obese controls. Additionally, LJP treatment relieved colonic shortening and reduced colonic levels of inflammatory factors TNF-α and IL-6. Further exploration of LJP treatment effects on mouse gut microbiota conducted via fecal 16S rRNA gene sequence-based gut microbiome profiling analysis revealed that LJP treatment increased the Bacteroidetes/Firmicutes ratio and increased gut abundances of probiotics Bacteroides acidifaciens, s_Lactobacillus intestinalis, and s_Lactobacillus murinus. In conclusion, these results collectively suggest that LJP use as a food supplement may alleviate obesity and related gut microbiota dysbiosis and intestinal inflammatory disorders.

The Effect of Laminaria japonica on Metabolic Syndrome: A Systematic Review of Its Efficacy and Mechanism of Action

Metabolic syndrome (MetS) is a medical condition characterized by abdominal obesity, insulin resistance, high blood pressure, and hyperlipidemia. An increase in the incidence of MetS provokes an escalation in health care costs and a downturn in quality of life. However, there is currently no cure for MetS, and the absence of immediate treatment for MetS has prompted the development of novel therapies. In accordance with recent studies, the brown seaweed Laminaria japonica (LJP) has anti-inflammatory and antioxidant properties, and so forth. LJP contains bioactive compounds used as food globally, and it has been used as a medicine in East Asian countries. We conducted a systematic review to examine whether LJP could potentially be a useful therapeutic drug for MetS. The following databases were searched from initiation to September 2021: PubMed, Web of Science, EMBASE, and Cochrane Central Register of Controlled Trials Library. Clinical trials and in vivo studies evaluating the effects of LJP on MetS were included. LJP reduces the oxidative stress-related lipid mechanisms, inflammatory cytokines and macrophage-related chemokines, muscle cell proliferation, and migration. Bioactive-glucosidase inhibitors reduce diabetic complications, a therapeutic target in obesity and type 2 diabetes. In obesity, LJP increases AMP-activated protein kinase and decreases acetyl-CoA carboxylase. Based on our findings, we suggest that LJP could treat MetS, as it has pharmacological effects on MetS.

Trimetazidine ameliorates hindlimb ischaemic damage in type 2 diabetic mice

BACKGROUND

Ischaemia caused by lower extremity artery stenosis is the main cause of peripheral artery disease (PAD) in patients with diabetes. Trimetazidine (TMZ) has traditionally been used as an anti-ischaemic drug for coronary artery disease. The effect of TMZ on PAD in a diabetic animal model and the underlying molecular mechanisms remain unclear.

METHODS

The db/db mice were challenged with femoral artery ligation (FAL), followed by TMZ treatment for 2 weeks. Scores on hindlimb ischaemia and function were evaluated. Histological and capillary density analyses of gastrocnemius were performed. The expression of vascular endothelial growth factor (VEGF) and myogenic regulators was also confirmed by Western blotting. We also detected serum intercellular adhesion molecule 1 (ICAM-1) level through ELISA.

RESULTS

Diabetic mice exhibited limb ulceration and motor dysfunction after FAL while TMZ-treated db/db mice exhibited milder ischaemic impairment. Furthermore, decreased capillary density in the gastrocnemius muscles of ischaemic hindlimb and reduced expressions of VEGF, myogenic markers, and serum ICAM-1 could be partially reversed by TMZ treatment.

CONCLUSION

TMZ may alleviate hindlimb ischaemic damage in db/db mice, at least partly, through enhancing angiogenesis and promoting myogenesis in ischaemia region.Key messagesTMZ intervention could alleviate hindlimb ischaemic damage in db/db mice.TMZ intervention could enhance angiogenesis and stimulate myogenesis in ischaemia region.

Multi-Pharmaceutical Activities of Chinese Herbal Polysaccharides in the Treatment of Pulmonary Fibrosis: Concept and Future Prospects

Pulmonary fibrosis is a fatal chronic progressive respiratory disease, characterized by continuous scarring of the lung parenchyma, leading to respiratory failure and death. The incidence of PF has increased over time. There are drugs, yet, there are some limitations. Hence, it is of importance to find new therapies and new drugs to replace the treatment of pulmonary fibrosis. In recent years, there have been a great number of research reports on the treatment of traditional Chinese medicine polysaccharides in various system fields. Among them, the treatment of PF has also gained extensive attention. This review summarized the source of polysaccharides, the drug activity of traditional Chinese medicine, and the protective effects on targets of Pulmonary fibrosis. We hope it can inspire researchers to design and develop polysaccharides, serving as a reference for potential clinical therapeutic drugs.

Polysaccharides from Laminaria japonica: an insight into the current research on structural features and biological properties

Laminaria japonica, one of the most widespread seafood consumed in China and many other nations, has been traditionally utilized as an effective therapeutically active substance for treating weight loss, phlegm elimination, and detumescence for more than 2000 years. Numerous studies have found that the polysaccharides play an indispensable role in the nutritional and medicinal value of L. japonica. Water extraction and alcohol precipitation method is the most used method. Approximately 56 LJPs were successfully isolated and purified from L. japonica, whereas only few of them were well characterized. Modern pharmacological studies have shown that L. japonica polysaccharides (LJPs) have high-order structural features and multiple biological activities, including anti-tumor, anti-thrombotic, anti-atherosclerosis, hypolipidemic, hypoglycemic, antioxidant, anti-inflammatory, renoprotective, and immunomodulatory. In addition, the structural characteristics of LJPs are closely related to their biological activity. In this review, the extraction and purification methods, structural characteristics, biological activities, clinical settings, toxicities, and structure-activity relationships of LJPs are comprehensively summarized. The structural characteristics and biological activities as well as the underlying molecular mechanisms of LJPs were also outlined. Furthermore, the clinical settings and structure-activity functions of LJPs were highlighted. Some research perspectives and challenges in the study of LJPs were also proposed.

Fucose as a new therapeutic target in renal transplantation

Ischaemia/reperfusion injury (IRI) is an inevitable and damaging consequence of the process of kidney transplantation, ultimately leading to delayed graft function and increased risk of graft loss. A key driver of this adverse reaction in kidneys is activation of the complement system, an important part of the innate immune system. This activation causes deposition of complement C3 on renal tubules as well as infiltration of immune cells and ultimately damage to the tubules resulting in reduced kidney function. Collectin-11 (CL-11) is a pattern recognition molecule of the lectin pathway of complement. CL-11 binds to a ligand that is exposed on the renal tubules by the stress caused by IRI, and through attached proteases, CL-11 activates complement and this contributes to the consequences outlined above. Recent work in our lab has shown that this damage-associated ligand contains a fucose residue that aids CL-11 binding and promotes complement activation. In this review, we will discuss the clinical context of renal transplantation, the relevance of the complement system in IRI, and outline the evidence for the role of CL-11 binding to a fucosylated ligand in IRI as well as its downstream effects. Finally, we will detail the simple but elegant theory that increasing the level of free fucose in the kidney acts as a decoy molecule, greatly reducing the clinical consequences of IRI mediated by CL-11.

Protection against peripheral artery disease injury by Ruan Jian Qing Mai formula via metabolic programming

Ruan Jian Qing Mai formula (RJQM), a multicomponent herbal formula, has been widely used to treat peripheral arterial disease (PAD) in China. However, its active compounds and mechanisms of action are still unknown. First, RNA sequencing analysis of 15 healthy and 16 PAD samples showed that 524 PAD differential genes were significantly enriched in Go Ontology (ribonucleotide metabolic process, oxidoreductase complex, and electron transfer activity), Kyoto Encyclopedia of Genes and Genomes (KEGG) and GSEA pathways (OXPHOS and TCA cycle), miRNA (MIR183), and kinase (PAK6). Fifty-three active ingredients in RJQM had similar structures to the seven drug molecules in CLUE. Then, network topology analysis of the 53 components-target-pathway-disease network yielded 10 active ingredients. Finally, computational toxicity estimations showed that the median lethal dose (LD50) of the 10 active ingredients was above 1000 mg/kg, and eight of them did not cause hepatotoxicity, mutagenicity, carcinogenicity, cytotoxicity, and immunotoxicity nor activate 12 toxic pathways. In conclusion, RJQM has a protection effect on PAD by regulating a complex molecular network. Part of the mechanism is associated with the regulation of OXPHOS by 10 active components, which may alleviate mitochondrial dysfunction and pathological metabolic programming.

Fucoidan attenuates hyperoxia-induced lung injury in newborn rats by mediating lung fibroblasts differentiate into myofibroblasts

Background

Hyperoxia-induced lung injury is one of the most common and frequent diseases in premature infants and may develop into bronchopulmonary dysplasia (BPD). Fucoidan, extracted from brown seaweed and brown algae, has anti-apoptosis, antioxidative and anti-fibrosis effects. This study aimed to explore whether fucoidan could alleviate hyperoxia-induced lung injury in newborn rats.

Methods

Lung wet-weight/dry-weight (W/D) ratio, total protein (TP) content, total cell counts, and lactate dehydrogenase (LDH) levels are used to evaluate lung injury. Masson staining is used to evaluate lung fibrotic. Tunnel assay and Hoechst 33258 assay were used to evaluate apoptosis. The levels of serum superoxide dismutase (SOD), malondialdehyde (MDA), and glutathione (GSH) were measured using ELISA to assess oxidative stress. Western blot assay was used to detect apoptosis-related proteins Bcl-1, Bax, and myofibroblast proteins α-SMA.

Results

The data indicating fucoidan treatment remarkably reduces the lung W/D ratio and TP content, total cell counts, and LDH levels in bronchoalveolar lavage fluid (BALF). Also, fucoidan treatment significantly inhibited cell apoptosis with the elevated expression of Bcl-2/Bax in cultured lung fibroblasts. Moreover, treatment with fucoidan suppressed the levels of MDA significantly and elevated the level of SOD and GSH, showing that oxidative stress was restrained by fucoidan. Furthermore, the decreased expression levels of α-SMA and collagen I was detected in fibroblast treated with fucoidan.

Conclusions

These data suggest fucoidan may protect the lung from hyperoxia via suppressing cell apoptosis, mitigating oxidative stress, and inhibiting lung fibroblasts from differentiating into myofibroblasts.

Structural Characterization and α-Glucosidase Inhibitory and Antioxidant Activities of Fucoidans Extracted from Saccharina japonica

Two sulfated fucoidan fractions (Lj3 and Lj5) were extracted from Saccharina japonica and then subjected to acid hydrolysis to obtain Lj3h and Lj5h. Lj3h and Lj5h were characterized using IR, methylation analysis, and mass spectrometry. It was found that Lj3h and Lj5h were homogeneous low molecular weight fucoidans. Specifically, Lj3h was composed of the main chain of 1,3-linked α-L-fucopyranose residues with sulfate at C-2 and/or C-4 and three different monosaccharides (galactose, glucose, mannose) branched at C-2 and/or C-4 of fucose residue. Lj5h contained backbones of alternating galactopyranose residues and fucopyranose residues attached via a 1→3 linkage (galactofucan) and 1→6 linked galactan. The sulfation pattern was mainly located at C2/C4 fucose or galactose residues and more branches occupied at C-4 of fucose residue and C-2, C-3 or/and C-6 of galactose residue. In vitro assay indicated that, among the four fucoidans tested, only Lj5 showed potent α-glucosidase inhibitory activity with IC50 of 153.27±22.89 μg/mL, and the two parent fucoidans, Lj3 and Lj5, showed better antioxidant activity than their derivatives. These findings highlight the structure and bioactivity diversity of Saccharina japonica-derived fucoidans.

Size-dependent whitening activity of enzyme-degraded fucoidan from Laminaria japonica

Fucoidan from Laminaria japonica is a kind of sulfate polysaccharide with high molecular weight (MW) and broad bioactivities. This study was performed to investigate the relationship between MW and whitening activity of fucoidan and to exploit a novel functional ingredient for whitening cosmetics. High sulfate content fucoidan was enzymic degraded by Flavobacterium RC2-3 produced fucoidanase. Two hours were enough for the enzyme degradation to achieve degraded fucoidan with favorable tyrosinase inhibitory ability. The whitening activity of different MW fucoidan fractions were evaluated by their tyrosinase inhibitory ability, antioxidant activity and cellular melanogenesis inhibitory ability. Results showed that in the MW range above 5 kDa, the smaller MW of fucoidan were related to the better whitening activity. The fucoidan fraction with the MW between 5-10 kDa, presented the best tyrosinase inhibitory activity (62.0%), antioxidant activity (48.3%) and excellent anti-melanogenesis ability in B16 cells, which could be applied as the whitening factor in cosmetics development.

Antioxidant Properties of Fucoidan Alleviate Acceleration and Exacerbation of Hippocampal Neuronal Death Following Transient Global Cerebral Ischemia in High-Fat Diet-Induced Obese Gerbils

Fucoidan, a natural sulfated polysaccharide, displays various biological activities including antioxidant properties. We examined the neuroprotective effect of fucoidan against transient global cerebral ischemia (tGCI) in high-fat diet (HFD)-induced obese gerbils and its related mechanisms. Gerbils received HFD for 12 weeks and fucoidan (50 mg/kg) daily for the last 5 days during HFD exposure, and they were subjected to 5-min tGCI. Pyramidal cell death was observed only in the CA 1 area (CA1) of the hippocampus in non-obese gerbils 5 days after tGCI. However, in obese gerbils, pyramidal cell death in the CA1 and CA2/3 occurred at 2 days and 5 days, respectively, after tGCI. In the obese gerbils, oxidative stress indicators (dihydroethidium, 8-hydroxyguanine and 4-hydroxy-2-nonenal) were significantly enhanced and antioxidant enzymes (SOD1 and SOD2) were significantly reduced in pre- and post-ischemic phases compared to the non-obese gerbils. Fucoidan treatment attenuated acceleration and exacerbation of tGCI-induced neuronal death in the CA1–3, showing that oxidative stress was significantly reduced, and antioxidant enzymes were significantly increased in pre- and post-ischemic phases. These findings indicate that pretreated fucoidan can relieve the acceleration and exacerbation of ischemic brain injury in an obese state via the attenuation of obesity-induced severe oxidative damage.

Low molecular-weight fucoidan protects against hindlimb ischemic injury in type 2 diabetic mice through enhancing endothelial nitric oxide synthase phosphorylation

BACKGROUND

Diabetes mellitus (DM) complications are associated with ischemic injury. Angiogenesis is a therapeutic strategy for diabetic foot. The aim of this study was to investigate the possible angiogenic effect of low molecular weight fucoidan (LMWF) in diabetic peripheral arterial disease (PAD).

METHODS

Diabetic db/db mice and age-matched C57BL/6 mice underwent femoral artery ligation followed by LMWF (30, 60, 80 mg/kg per day, p.o.) or cilostazol (30 mg/kg/day, p.o.) treatment for 6 weeks. Endothelium-dependent vasodilation and blood flow of the hindlimb were measured. Histological and western blot analyses of CD34, vascular endothelial growth factor (VEGF), eNOS, and inflammatory factors in the gastrocnemius were performed. The effects of LMWF were confirmed in human umbilical vein endothelial cells (HUVEC).

RESULTS

Diabetic mice with ligation exhibited hindlimb ulceration, hydrosarca, and necrosis, increased expression of inflammatory factors, and decreased levels of VEGF and eNOS phosphorylation. Treatment with LMWF markedly ameliorated foot lesions, suppressed expression of inflammatory factors, and improved plantar perfusion by promoting endothelium-dependent vasodilation and revascularization in diabetic PAD mice. In high-glucose treated HUVEC, LMWF (40 μg/mL) reversed blunted endothelial cell proliferation, migration, and tube formation, and promoted eNOS phosphorylation and VEGF expression, whereas HUVEC pretreatment with 100 μmol/L N^G -nitro-l-arginine methyl ester, an eNOS antagonist, markedly inhibited the effects of LMWF.

CONCLUSION

This study demonstrates that LMWF alleviates hindlimb ischemic damage, at least in part by promoting eNOS phosphorylation, nitric oxide production, and VEGF expression, resulting in enhanced angiogenesis in the ischemic region.