Oral administration of PEDV-dissolved Alg-CS gel induces high and sustained mucosal immunity in mice.

Porcine epidemic diarrhea (PED) is a serious disease in piglets that leads to high mortality. An effective measure that provides higher IgA levels in the intestine and milk is required to decrease losses. Porcine epidemic diarrhea virus (PEDV) was dissolved in calcium alginate (Alg) and combined with chitosan (CS) via electrostatic interactions between cationic chitosan and anionic alginate to create a porous gel (Alg-CS+PEDV). The gel was used to immunize mice orally or in combination with subcutaneous injections of inactivated PEDV vaccine. At 12 and 24 days after immunization, levels of IgA and IgG in Alg-CS+PEDV were higher than with normal PEDV oral administration. At 24 days after immunization, the concentration of IFN-γ in Alg-CS+PEDV was higher than with normal PEDV oral administration. Furthermore, oral administration combining subcutaneous immunization induced higher levels of IgG and IgA than oral administration alone. Our study provides a new method for the preparation and administration of oral vaccines to achieve enhanced mucosal immunity against PEDV.

Efficacy and safety of MC-003 solution for endoscopic mucosal or submucosal resection: a prospective, multicenter, randomized, triple-blinded, parallel-group, phase III study.

BACKGROUND AND AIMS: The safety and efficacy of solutions for submucosal injection are critical for endoscopic resection of gastric adenomas or early gastric cancers. Although several injectable solutions have been introduced for endoscopic resection, they have some limitations. We aimed to compare the efficacy of the new sodium alginate-based solution MC-003 with that of normal saline (NS; 0.9% sodium chloride). METHODS: In this randomized, triple-blind study, 70 patients were initially enrolled for EMR or endoscopic submucosal dissection (ESD). The main outcomes included the need for additional injections, completion of en bloc resection, and occurrence of adverse events. RESULTS: Each group ultimately included 34 patients. Complete en bloc resections were achieved in all patients (P = 1.000). The MC-003 group had more peri-neoplasm tissue fibrosis (P = .056) and needed fewer additional injections for lesions >15 mm (P = .037), located in the distal portion of the stomach (P = .007), and during ESD procedures (P = .001). The adverse event rate was comparable in both groups. CONCLUSIONS: MC-003 outperformed NS in reducing the need for additional injections during en bloc resection, particularly in larger lesions located in the distal portion of the stomach (where most lesions were found) during ESD procedures, without increasing the incidence of serious adverse events. MC-003 is a promising submucosal injectable solution in real-world clinical settings.

Model of Chronic Thromboembolic Pulmonary Hypertension in Rats Caused by Repeated Intravenous Administration of Partially Biodegradable Sodium Alginate Microspheres.

Chronic thromboembolic pulmonary hypertension (CTEPH) is a rare and life-threatening complication of pulmonary embolism. As existing animal models of CTEPH do not fully recapitulate complex disease pathophysiology, we report a new rat model for CTEPH evoked by repetitive embolization of the distal pulmonary artery branches with partially biodegradable alginate microspheres (MSs). MSs (180 ± 28 µm) were intravenously administered eight times at 4-day intervals; control animals received saline. The validity of the model was confirmed using transthoracic echocardiography, exercise testing, catheterization of the right ventricle, and histological examination of the lung and heart. The animals in the CTEPH group demonstrated a stable increase in right ventricular systolic pressure (RVSP) and decreased exercise tolerance. Histopathological examination revealed advanced medial hypertrophy in the small pulmonary arteries associated with fibrosis. The diameter of the main pulmonary artery was significantly larger in the CTEPH group than in the control group. Marinobufagenin and endothelin-1 serum levels were significantly elevated in rats with CTEPH. In conclusion, repetitive administration of alginate MSs in rats resulted in CTEPH development characterized by specific lung vasculature remodeling, reduced exercise tolerance, and a persistent rise in RVSP. The developed model can be used for pre-clinical testing of promising drug candidates.

Encapsulation of Synthesized Plant Growth Regulator Based on Copper(II) Complex in Chitosan/Alginate Microcapsules.

A new copper complex, trans-diaqua-trans-bis [1-hydroxy-1,2-di (methoxycarbonyl) ethenato] copper (abbreviation Cu(II) complex), was synthesized and its plant growth regulation properties were investigated. The results show a sharp dependence of growth regulation activity of the Cu(II) complex on the type of culture and its concentration. New plant growth regulator accelerated the development of the corn root system (the increase in both length and weight) but showed a smaller effect on the development of the wheat and barley root systems. Stimulation of corn growth decreased with increasing Cu(II) complex concentration from 0.0001% to 0.01% (inhibition at high concentrations-0.01%). The development of corn stems was also accelerated but to a lesser extent. Chitosan-coated calcium alginate microcapsules suitable for delivery of Cu(II) complex to plants were prepared and characterized. Analysis of the FTIR spectrum showed that complex molecular interactions between functional groups of microcapsule constituents include mainly electrostatic interactions and hydrogen bonds. Microcapsules surface exhibits a soft granular surface structure with substructures consisting of abundant smaller particles with reduced surface roughness. Release profile analysis showed Fickian diffusion is the rate-controlling mechanism of Cu(II) complex releasing. The obtained results give new insights into the complexity of the interaction between the Cu(II) complex and microcapsule formulation constituents, which can be of great help in accelerating product development for the application in agriculture.

Nanoparticles integrating natural and synthetic polymers for in vivo insulin delivery.

The aims of the current study were to develop insulin-loaded nanoparticles comprised of various polymers at different compositions, and to evaluate their ability to lower blood glucose levels in diabetic rats following subcutaneous and oral administrations. Several combinations of natural and synthetic polymers have been utilized for preparation of nanoparticles including, chitosan, alginate, albumin and Pluronic. Nanosized (170 nm-800 nm) spherical particles of high encapsulation efficiency (15-52%) have been prepared. Composition and ratios between the integrated polymers played a pivotal role in determining size, zeta potential, and in vivo hypoglycemic activity of particles. After subcutaneous and oral administration in diabetic rats, some of the insulin-loaded nanoparticles were able to induce much higher hypoglycemic effect as compared to the unloaded free insulin. For instance, subcutaneous injection of nanoparticles comprised of chitosan combined with sodium tripolyphosphate, Pluronic or alginate/calcium chloride, resulted in comparable hypoglycemic effects to free insulin, at two-fold lower dose. Nanoparticles were well-tolerated after oral administration in rats, as evidenced by by measuring levels of alanine aminotransferase, aspartate aminotransferases, albumin, creatinine and urea. This study indicates that characteristics and delivery efficiency of nanomaterials can be controlled via utilizing several natural/synthetic polymers and by fine-tuning of combination ratio between polymers.

pH-sensitive chitosan-deoxycholic acid/alginate nanoparticles for oral insulin delivery.

Oral absorption of peptides/proteins is usually compromised by various gastrointestinal tract barriers. To improve delivery efficiency, chitosan-conjugated deoxycholic acid (CS-DCA) coupled with sodium alginate (ALG) was prepared to load insulin into pH-sensitive nanoparticles. The insulin-loaded chitosan-deoxycholic acid/alginate nanoparticles (CDA NPs) were characterized by size (143.3 ± 10.8 nm), zeta potential (19.5 ± 1.6 mV), entrapment efficiency (61.14 ± 1.67%), and insulin drug loading (3.36 ± 0.09%). The CDA NPs exhibited pH-triggered release characteristics in vitro and protected the wrapped insulin from gastric degradation. Stability of the CDA NPs in enzyme-containing simulated gastrointestinal fluids suggested that the NPs could partially protect the wrapped insulin from enzymatic degradation. Additionally, CS-DCA-modified NPs promoted the permeability of Caco-2 cells and enhanced intracellular absorption of FITC-labeled insulin by 9.4 and 1.2-folds, when compared to insulin solution and unmodified NPs, respectively. The positively charged NPs increased intestinal villi adhesion and enhanced insulin absorption in the intestines of diabetic rat models. Furthermore, the hypoglycemic test showed that CDA NPs prolonged insulin release in vivo and exerted a remarkable hypoglycemic effect on diabetic rats with an oral bioavailability of 15%. In conclusion, CDA NPs is a potential oral insulin delivery system.

Injectable and Radiopaque Liquid Metal/Calcium Alginate Hydrogels for Endovascular Embolization and Tumor Embolotherapy.

Improved endovascular embolization can contribute to assistant treatment for patients. However, many traditional embolic materials, such as metal microcoils or liquid embolic agents, are associated with limitations of coil migration or recanalization. Herein, as the first trial, an injectable and radiopaque liquid metal/calcium alginate (LM/CA) hydrogel is introduced and fabricated as a candidate for endovascular embolization and tumor embolotherapy through developing LM droplets as radiopaque units into biocompatible calcium alginate cross-linked network. The adoption of LM droplets makes hydrogels radiopaque under X-ray and CT scan, which significantly facilitates the tracking of material location during surgical vascular operation. In addition, in vitro and in vivo experiments prove that such smart hydrogel could convert from liquid to solid rapidly via cross-linking, showing pretty flexible and controllable functions. Benefiting from these properties, the hydrogel can be performed in blood vessels through injection via syringes and then served as an embolic material for endovascular embolization procedures. In vivo experiments demonstrate that such hydrogels can occlude arteries and block blood flow until they ultimately lead to ischemic necrosis of tumors and partial healthy tissues. Overall, the present LM/CA hydrogels are promising to be developed as new generation embolic materials for future tumor embolotherapy.

High efficacy and economical procedure of oral vaccination against Lactococcus garvieae/Streptococcus iniae in rainbow trout (Oncorhynchus mykiss).

The present study was aimed to examine the efficacy of chitosan-alginate coated vaccines against pathogenicity of Lactococcus garvieae and Streptococcus iniae in rainbow trout. Fish were divided into four groups including: Group A: fish immunized by chitosan-alginate coated vaccine, Group B: fish immunized by non-coated vaccine, Group C: fish feed by chitosan-alginate coated pellets without vaccine and Group D: fish feed by basic diet (non-coated and without vaccine). In groups A and B, the vaccination was carried out for 14 days and after that supplemented with fundamental diet (control diet). Comparable to groups A and B, fish of group C were also fed 14 days with test diets and after that fed control food. On day 0, 20, 40 and 60 of the experiment, serum samples were given. Fish have been challenged with live L. garvieae and S. iniae after 60 days. The levels of bactericidal activity and complement activity among innate immunity components extended on day 20 of the research and after that decreased in group A and B (P < 0.05) all through the examination. The relative expression of IL-6 and IgM in groups A and B extended on examination day 20. The expression of these genes illustrated no advancements in different groups in during the examination (P > 0.05). In group A, the serum antibody titer against L. garvieae and S. iniae broadly raised on day 40 and 60 of examination, whereas in group B, the immune response titer against S. iniae and L. garvieae illustrated a significant elevation on day 60 of the trial (P < 0.05). After challenge with live bacteria, survival rate of 83 ± 9.1%(challenged with S. iniae) and 72.18 ± 9.8% (challenged with L. garvieae) were gotten independently in group A, which were higher than survival of other exploratory groups (P < 0.05). In conclusion, the results of the present examination appear that the orally vaccination of rainbow trout with chitosan-alginate covered vaccine stimulates immunity system and also efficiently protects rainbow trout against Lactococcus garvieae and Streptococcus iniae.

Immunogenicity and protective efficacy of Yersinia ruckeri lipopolysaccharide (LPS), encapsulated by alginate-chitosan micro/nanoparticles in rainbow trout (Oncorhyncus mykiss).

Considering the many advantages of oral vaccines in aquaculture, several studies have been conducted in this area recently. In this study, immunization and protective power of the oral vaccine of Yersinia ruckeri encapsulated with Alginate-Chitosan micro/nanoparticles were evaluated in rainbow trout. For this purpose, 720 juvenile rainbow trout (9 ± 1.8 g) were divided into 8 groups in three replications (30 fish each) as follows: Groups A, B and C, were immunized with Yersinia ruckeri lipopolysaccharide (LPS), LPS+Formalin Killed Cells (FKC) and FKC alone, groups D, E, and F were immunized with encapsulated LPS, LPS+FKC and FKC, respectively. The G and H groups considered as encapsulated and non-encapsulated control, respectively. Micro/nanoencapsulation with alginate-chitosan was performed by internal emulsification method and vaccination were conductrd in the first and third weeks via oral route. Sampling was performed on days 0, 30, and 60 of experiment. Anti Y. ruckeri antibody titer in serum, intestine and skin mucus were measured via ELISA method. Non-specific immune response including: serum lysozyme, complement, bactericidal and respiratory burst activity, serum protein and globulin level, as well as white blood cell count were compared among the groups. The expression of IgT gene in the intestine and TCR gene in the anterior kidney were also investigated. At the end of the study, the fish were challenged with Y. ruckeri through immerssion and intraperitoneal routs and the relative survival rate was evaluated. Result showed that the antibody level in serum, skin and intestine was significantly higher in group E and F than control groups (P < 0.05), meanwhile serum, skin and intestine antibody level in all vaccinated groups were significantly (P < 0.01) higher in day 30 and 60 compare to zero day. Non-specific immunity factors including: serum lysozyme, complement, and respiratory burst activity as well as WBC, protein and Globulin level were significantly higher in E and F groups not only in day 30 but also in day 60 of experiment (P < 0.05). Cumulative mortality following injection and bath challenge were significantly (P = 0.004) lower (35%-45%) in groups E and F compare to control group (80%). The IgT and TCR gene expression in groups D, E and F were significantly higher (P < 0.05) than control group. Highest upregulation of IgT and TCR gene expression in vaccinated groups were seen at day 30 and 60 respectively which were significantly (P < 0.001) higher than day zero. Generally, it can be concluded that nano/micronanoencapsulation of Y. ruckeri FKC+LPS with chitosan-alginate, not only increases protective efficacy of oral vaccine, but improves specific and non-specific immune responses in rainbow trout.

Oral administration of microencapsulated egg yolk immunoglobulin (IgY) in turbot (Scophthalmus maximus) to combat against Edwardsiella tarda 2CDM001 infections.

Edwardsiellosis, an extremely harmful disease can be caused by Edwardsiella tarda, severely restricts the development of turbot (Scophthalmus maximus) farming worldwide, especially in China. This study aimed to establish an effective and feasible prophylaxis by feeding chitosan-alginate coated egg yolk immunoglobulin (IgY) against E. tarda 2CDM001 infections in the process of turbot farming. Enzyme-linked immunosorbent assays proved that the obtained specific IgY could specifically target E. tarda 2CDM001 and five other E. tarda isolates (1a5p, Hz-s, 1a1s, fs-a1 and 58p8). In-vitro, the bacteriostatic effects of specific IgY showed dose dependencies at concentrations ranging from 1 to 10 mg/mL. Moreover, E. tarda 2CDM001 incubated with 10 mg/mL specific IgY could induce the destruction of cell wall structures and significantly decrease the bacterial surface hydrophobicity (p < 0.05). In this study, turbots were challenged with 107 CFU E. tarda 2CDM001 after seven days of continuous feeding with basal diets containing microencapsulated IgYs. Survival rates of the 5%, 3% and 1% microencapsulated specific IgY groups were 63.3%, 56.7% and 20% on the tenth day post infection, respectively, while the turbots in the positive control and non-specific IgY groups all died within ten days. Oral administration of basal diets containing 5% microencapsulated specific IgY significantly reduced IL-1ß, IL-8, TNF-α and C3 transcript levels in the head kidney and spleen of turbots compared with the positive and non-specific IgY groups at 24 h after E. tarda 2CDM001 challenging (p < 0.05). Pathological increase of leukocytes in the specific IgY group was significantly lower than that in the positive control and non-specific IgY groups (p < 0.05), decreasing slowly after 24 h of infection and showing a recovery trend. Erythrocyte counts and hemoglobin concentrations of turbots in positive and non-specific IgY groups showed a marked decrease compared with the negative and specific groups at 96 h after E. tarda 2CDM001 infection (p < 0.05). These results suggest that passive immunity via feeding microencapsulated specific IgY could be used as a valuable preventative in turbot against E. tarda 2CDM001 infections.

Oral immunization of carps with chitosan-alginate microcapsule containing probiotic expressing spring viremia of carp virus (SVCV) G protein provides effective protection against SVCV infection.

Spring viremia of carp (SVC) is highly contagious and lethal disease in cyprinid fish, in particular common carps (Cyprinus carpio), causing numerous economic losses to the aquaculture industry. SVC is presently endemic disease in Europe, America, and several countries in Asia and its causative agent is spring viremia of carp virus (SVCV). In this study, a chitosan-alginate microcapsule probiotic vaccine expressing G protein of SVCV was prepared, and the immunogenicity in carps of orally administrated with the microcapsule probiotic vaccine was evaluated. Our results showed that the microcapsule probiotic vaccine can induce potent antigen-specific immune responses in carps via oral vaccination, and provide effective anti-SVCV protection for carps. Significantly, the microcapsule probiotic vaccine is suitable for mass fish immunization, suggesting a promising vaccine strategy for fish.

Alginate oligosaccharide improves lipid metabolism and inflammation by modulating gut microbiota in high-fat diet fed mice.

Alginate oligosaccharides are associated with some beneficial health effects. Gut microbiota is one of the most recently identified factors in the development of several metabolic diseases induced by high-fat diet. Our objective was to evaluate how alginate oligosaccharides impact on high-fat diet­induced features of metabolic disorders and whether this impact is related to modulations in the modulation of the gut microbiota. C57BL/6J mice were fed with chow diet, high-fat diet, or high-fat diet supplemented with alginate oligosaccharides for 10 weeks. Alginate oligosaccharide treatment improved lipid metabolism, such as reducing levels of TG and LDL-C and inhibiting expression of lipogenesis genes. Alginate oligosaccharide administration reduced the levels of fasting blood glucose and increased the levels of serum insulin. Alginate oligosaccharide treatment was found to lower the expression of markers of inflammation, including IL1ß and CD11c. Alginate oligosaccharide treatment modulated gut microbial communities and markedly prompted the growth of Akkermansia muciniphila, Lactobacillus reuteri, and Lactobacillus gasseri. Additionally, alginate oligosaccharide intervention significantly increased concentrations of short-chain fatty acids, such as acetic acid, propionic acid, and butyric acid, as well as decreased levels of endotoxin. Alginate oligosaccharides exert beneficial effects via alleviating metabolic metrics induced by high-fat diet, which is associated with increase in A. muciniphila, L. reuteri, and L. gasseri, as well as the release of microbiota-dependent short-chain fatty acids and inhibition of endotoxin levels.

Sodium Alginate as a Potential Therapeutic Filler: An In Vivo Study in Rats.

Filler injection demand is increasing worldwide, but no ideal filler with safety and longevity currently exists. Sodium alginate (SA) is the sodium salt of alginic acid, which is a polymeric polysaccharide obtained by linear polymerization of two types of uronic acid, d-mannuronic acid (M) and l-guluronic acid (G). This study aimed to evaluate the therapeutic value of SA. Nine SA types with different M/G ratios and viscosities were tested and compared with a commercially available sodium hyaluronate (SH) filler. Three injection modes (onto the periosteum, intradermally, or subcutaneously) were used in six rats for each substance, and the animals were sacrificed at 4 or 24 weeks. Changes in the diameter and volume were measured macroscopically and by computed tomography, and histopathological evaluations were performed. SA with a low M/G ratio generally maintained skin uplift. The bulge gradually decreased over time but slightly increased at 4 weeks in some samples. No capsule formation was observed around SA. However, granulomatous reactions, including macrophage recruitment, were observed 4 weeks after SA implantation, although fewer macrophages and granulomatous reactions were observed at 24 weeks. The long-term volumizing effects and degree of granulomatous reactions differed depending on the M/G ratio and viscosity. By contrast, SH showed capsule formation but with minimal granulomatous reactions. The beneficial and adverse effects of SA as a filler differed according to the viscosity or M/G ratio, suggesting a better long-term volumizing effect than SH with relatively low immunogenicity.

Treatment of hard-to-heal leg ulcers with hyaluronic acid, sodium alginate and negative pressure wound therapy.

OBJECTIVE: Hard-to-heal lower extremity ulcer is a common healthcare problem and can lead to a poor quality of life (QoL). Despite the advances in wound care, conventional therapies, such as necrotic tissue debridement, cleansing, treatment of infection and local treatment with dressing application are still considered the standard of care in patients with hard-to-heal leg ulcers. However, managing hard-to-heal ulcers that do not respond well to these methods has led to new treatment strategies. In this study, the effects of hyaluronic acid (HA) and sodium alginate (SA), combined with negative pressure wound therapy (NPWT), in patients with hard-to-heal leg ulcers are evaluated. METHOD: Patients with hard-to-heal lower extremity ulcers were treated with HA-SA combined with NPWT (HA-SA-NWPT, n=11), or conventional therapy (n=14), between June 2014 and September 2015. Demographics, comorbidities, time to complete healing and change in wound area were recorded and compared. RESULTS: A total of 25 patients took part. Complete healing was achieved in 63.6% (n=7) of the patients in the HA-SA with NPWT group, compared with 14.3% (n=2) of the patients in the conventional therapy group (p=0.017). The mean decrease in wound size was significantly higher in the HA-SA-NPWT group than in the conventional therapy group (73.8% versus 34.8%, respectively, p=0.029). Despite a shorter healing period in the HA-SA-NPWT group than in the conventional group, no statistically significant difference was found between groups for time to complete healing (37 days versus 55 days, respectively). CONCLUSION: These results demonstrate that the combination of HA-SA-NPWT is a promising treatment for decreasing the healing time and increasing the success rate by their synergistic effect on wound healing in hard-to-heal lower extremity ulcers. However, further studies with a larger number of patients are needed to confirm the results.

Regenerated oxidised cellulose versus calcium alginate in controlling bleeding from malignant breast cancer wounds: randomised control trial study protocol.

OBJECTIVE: Malignant wounds due to breast cancer can present with recurrent episodes of bleeding in the tumour tissue. This study will compare the efficacy of a calcium alginate dressing (Biatain, Coloplast A/S, Denmark) and a regenerated oxidised cellulose dressing (Surgicel, Ethicon, LLC, Puerto Rico). PROTOCOL: A total of 24 patients with breast cancer and bleeding, malignant wounds will be enrolled in the randomised, controlled, open study, conducted at a hospital specialising in breast cancer treatment and at another hospital specialising in palliative care. Patients over 18 years old, with bleeding and willing to undergo venipuncture for blood collection will be included. All enrolled patients will be randomised for allocation to an experimental group (regenerated oxidised cellulose dressing) or a control group (calcium alginate dressing). The main intervention will consist of the application of the haemostatic product, assessment of digital pressure and estimation of the time required for haemostasis. OUTCOMES: Key outcome measures will be the percentage of patients with haemostasis within 20 minutes, observation of haemostasis after three, five and 10 minutes, in addition to recurrence of bleeding and the quantity of product used. DISCUSSION: To our knowledge, this is the first study to evaluate the effectiveness of haemostatic products in malignant wounds. This type of wound is poorly explored in the literature and, among its signs and symptoms, bleeding is poorly studied. The completion of this study will provide a more robust rationale for clinical decision-making related to the control of bleeding in malignant breast cancer wounds in the context of evidence-based nursing practices.

Alginate Oligosaccharide Alleviates Monocrotaline-Induced Pulmonary Hypertension via Anti-Oxidant and Anti-Inflammation Pathways in Rats.

Pulmonary arterial hypertension (PAH) is a serious and fatal cardiovascular disorder characterized by increased pulmonary vascular resistance and progressive pulmonary vascular remodeling. The underlying pathological mechanisms of PAH are multi-factorial and multi-cellular. Alginate oligosaccharide (AOS), which is produced by depolymerizing alginate, shows better pharmacological activities and beneficial effects. The present study was undertaken to investigate the effects and potential mechanisms of AOS-mediated alleviation of pulmonary hypertension. Pulmonary hypertension was induced in Sprague-Dawley rats by a single intraperitoneal injection of monocrotaline (MCT; 60 mg/kg). Five weeks after the injection of MCT, AOS (5, 10, and 20 mg·kg-1·d-1) was injected intraperitoneally for another three weeks. The results showed that AOS prevented the development of MCT-induced pulmonary hypertension and right ventricular hypertrophy in a dose-dependent manner. AOS treatment also prevented MCT-induced pulmonary vascular remodeling via inhibition of the TGF-ß1/p-Smad2 signaling pathway. Furthermore, AOS treatment downregulated the expression of malondialdehyde, nicotinamide adenine dinucleotide phosphate oxidase, and pro-inflammatory cytokines, decreased macrophage infiltration, and upregulated the expression of anti-inflammatory cytokines. These findings indicate that AOS exerts anti-oxidative and anti-inflammatory effects in pulmonary arteries, which may contribute to the alleviation of pulmonary hypertension and pulmonary vascular remodeling.

Exploring Endolysin-Loaded Alginate-Chitosan Nanoparticles as Future Remedy for Staphylococcal Infections.

Endolysins are a novel class of antibacterials with proven efficacy in combating various bacterial infections, in vitro and in vivo. LysMR-5, an endolysin derived from phage MR-5, demonstrated high lytic activity in our laboratory against multidrug-resistant S. aureus (MRSA) and S. epidermidis strains. However, endolysin and proteins in general are associated with instability and short in vivo half-life, consequently limiting their usage as pharmaceutical preparation to treat bacterial infections. Nanoencapsulation of endolysins could help to achieve better therapeutic outcome, by protecting the proteins from degradation, providing sustained release, thus could increase their stability, shelf life, and therapeutic efficacy. Hence, in this study, the feasibility of alginate-chitosan nanoparticles (Alg-Chi NPs) to serve as drug delivery platform for LysMR-5 was evaluated. LysMR-5-loaded nanoparticles were prepared by calcium ion-induced pre-gelation of alginate core and its complexation with chitosan. The formation of nanoparticles was confirmed on the basis of DLS, zeta potential, and electron microscopy imaging. The LysMR-5-loaded nanoparticles presented a hydrodynamic diameter of 276.5 ± 42, a PDI of 0.342 ± 0.02, a zeta potential - 25 mV, and an entrapment efficiency of 62 ± 3.1%. The potential ionic interaction between alginate, chitosan, and LysMR-5 was investigated by FT-IR and SEM-EDX analysis. Using scanning electron microscopy (SEM) and transmission electron microscopy (TEM), nano-sized particles with characteristic morphology were seen. Different antibacterial assays and SDS-PAGE analysis showed no change in endolysin's structural integrity and bioactivity after entrapment. A direct antibacterial effect of blank Alg-Chi Nps, showing enhanced bactericidal activity upon LysMR-5 loading, was observed against S. aureus. At physiological pH (7.2), the release profile of LysMR-5 from Alg-Chi NPs showed a biphasic release and followed a non-Fickian release mechanism. The biocompatible nature as revealed by cytocompatibility and hemocompatibility studies endorsed their use as drug delivery system for in vivo studies. Collectively, these results demonstrate the potential of Alg-Chi NPs as nano-delivery vehicle for endolysin LysMR-5 and other therapeutic proteins for their use in various biomedical applications.

A thermo-responsive alginate nanogel platform co-loaded with gold nanoparticles and cisplatin for combined cancer chemo-photothermal therapy.

The current interest in cancer research is being shifted from individual therapy to combinatorial therapy. In this contribution, a novel multifunctional nanoplatform comprising alginate nanogel co-loaded with cisplatin and gold nanoparticles (AuNPs) has been firstly developed to combine photothermal therapy and chemotherapy. The antitumor efficacy of the as-prepared nanocomplex was tested against CT26 colorectal tumor model. The nanocomplex showed an improved chemotherapy efficacy than free cisplatin and caused a significantly higher tumor inhibition rate. The in vivo thermometry results indicated that the tumors treated with the nanocomplex had faster temperature rise rate under 532 nm laser irradiation and received dramatically higher thermal doses due to optical absorption properties of AuNPs. The combined action of chemo-photothermal therapy using the nanocomplex dramatically suppressed tumor growth up to 95% of control and markedly prolonged the animal survival rate. Moreover, tumor metabolism was quantified by [18F]FDG (2-deoxy-2-[18F]fluoro-D-glucose)-positron emission tomography (PET) imaging and revealed that the combination of the nanocomplex and laser irradiation have the potential to eradicate microscopic residual tumor to prevent cancer relapse. Therefore, the nanocomplex can afford a potent anticancer efficacy whereby heat and drug can be effectively deliver to the tumor, and at the same time the high dose-associated side effects due to the separate application of chemotherapy and thermal therapy could be potentially reduced.

The Prevention of Hepatectomy-Induced Adhesions by Bilayer Sponge Composed of Ultrapure Alginate.

BACKGROUND: Adhesion formation is a critical issue in surgery, particularly in hepatectomy. The present study aimed to develop a bilayer adhesion barrier comprising alginate (Alg) of different molecular weight (Mw). It was expected that a slowly dissolving layer remains on the cut surface, functioning as a physical barrier, whereas a rapidly dissolving layer widely distributes in the peritoneal cavity to prevent de novo adhesions. METHODS: Bilayer Alg sponges were fabricated using low Mw Alg for the upper layer and high Mw Alg for the bottom layer. The dissolution behavior of each layer was evaluated in vitro in peritoneum-like environments. We constructed a Pean crush hepatectomy-induced adhesion model in rats. The effects of the bilayer sponge on cut surface and de novo adhesions were separately evaluated in terms of their extent and grade. RESULTS: The Alg sponge layer with low Mw dissolved faster than that with high Mw in vitro. One week after the hepatectomy, although no significant decrease in adhesion extent on the cut surface was observed in rats that received Seprafilm and Interceed, treatment with Alg bilayer sponge significantly decreased the adhesion extent to 38% of that without treatment. Moreover, a significant decrease in de novo adhesion extent was observed in the Alg bilayer sponge compared with the Interceed group. CONCLUSIONS: The Alg bilayer sponge was effective for preventing both cut surface and de novo adhesions in the rat Pean crush hepatectomy model. The simple yet functional design of the Alg bilayer sponge can facilitate its use in future clinical practice.

The Efficacy of an Ultrapure Alginate Gel in Reducing Adhesion Formation in a Rat Model of Blood Contamination.

BACKGROUND: Formation of peritoneal adhesions is the most frequent complication of abdominal and pelvic surgery and comprises a lifelong risk of adhesion-related morbidity and mortality. Some of the existing antiadhesive barriers are less effective in the presence of blood. In this study, we investigate the efficacy and safety of ultrapure alginate gel in the presence of blood. METHODS: In experiment 1 (30 rats), 1 mL ultrapure alginate gel was compared with no intervention in a model of cecal abrasion and persisting peritoneal bleeding by incision of the epigastric artery. In experiment 2 (30 rats), 2 mL ultrapure alginate gel was compared with no intervention in a model where a 1 mL blood clot was instilled intra-abdominally and a cecal resection was performed. The primary endpoint was the incidence and severity of adhesions after 14 d. RESULTS: In experiment 1, seven of 15 rats in the experimental group had intra-abdominal adhesions compared with 13 of 15 rats in the control group (P = 0.05); 3 of 15 rats had adhesions at the site of injury compared with 12 of 15 rats in the control group (P < 0.01). The severity and extent of adhesions was also reduced (P < 0.01). In experiment 2, 12 of 13 rats had adhesions compared with 13 of 14 rats in the control group (P = 1.00). CONCLUSIONS: Ultrapure alginate gel reduces the incidence and severity of adhesion in the presence of persisting bleeding, but not in a model of cecal resection and blood clot.