Development of a novel beta-glucan supplemented hydrogel spray formulation and wound healing efficacy in a db/db diabetic mouse model.

To relieve the severe economic and social burdens and patient suffering caused by the increasing incidence of chronic wounds, more effective treatments are urgently needed. In this study, we focused on developing a novel sprayable wound dressing with the active ingredient ß-1,3/1,6-glucan (ßG). Since ßG is already available as the active ingredient in a commercial wound healing product provided as a hydrogel in a tube (ßG-Gel), the sprayable format should bring clinical benefit by being easily sprayed onto wounds; whilst retaining ßG-Gel's physical stability, biological safety and wound healing efficacy. Potentially sprayable ßG hydrogels were therefore formulated, based on an experimental design setup. One spray formulation, named ßG-Spray, was selected for further investigation, as it showed favorable rheological and spraying properties. The ßG-Spray was furthermore found to be stable at room temperature for more than a year, retaining its rheological properties and sprayability. The cytotoxicity of ßG-Spray in keratinocytes in vitro, was shown to be promising even at the highest tested concentration of 100 µg/ml. The ßG-Spray also displayed favorable fluid affinity characteristics, with a capacity to both donate and absorb close to 10% fluid relative to its own weight. Finally, the ßG-Spray was proven comparably effective to the commercial product, ßG-Gel, and superior to both the water and the carrier controls (NoßG-Spray), in terms of its ability to promote wound healing in healing-impaired animals. Contraction was found to be the main wound closure mechanism responsible for the improvement seen in the ßG-treatment groups (ßG-Spray and ßG-Gel). In conclusion, the novel sprayable ßG formulation, confirmed its potential to expand the clinical use of ßG as wound dressing.

Multifunctional Nanofibrous Dressing with Antimicrobial and Anti-Inflammatory Properties Prepared by Needle-Free Electrospinning.

An active wound dressing should address the main goals in wound treatment, which are improved wound healing and reduced infection rates. We developed novel multifunctional nanofibrous wound dressings with three active ingredients: chloramphenicol (CAM), beta-glucan (ßG) and chitosan (CHI), of which ßG and CHI are active nanofiber-forming biopolymers isolated from the cell walls of Saccharomyces cerevisiae and from shrimp shells, respectively. To evaluate the effect of each active ingredient on the nanofibers' morphological features and bioactivity, nanofibers with both ßG and CHI, only ßG, only CHI and only copolymers, polyethylene oxide (PEO) and hydroxypropylmethylcellulose (HPMC) were fabricated. All four nanofiber formulations were also prepared with 1% CAM. The needle-free NanospiderTM technique allowed for the successful production of defect-free nanofibers containing all three active ingredients. The CAM-containing nanofibers had a burst CAM-release and a high absorption capacity. Nanofibers with all active ingredients (ßG, CHI and CAM) showed a concentration-dependent anti-inflammatory activity, while maintaining the antimicrobial activity of CAM. The promising anti-inflammatory properties, together with the high absorption capacity and antimicrobial effect, make these multifunctional nanofibers promising as dressings in local treatment of infected and exuding wounds, such as burn wounds.

Beta-glucan-loaded nanofiber dressing improves wound healing in diabetic mice.

The increased prevalence of chronic wounds requires novel treatment options. The aim of this study was to develop a beta-glucan (ßG)-loaded nanofiber wound dressing. Nanofibers were prepared using the needle-free Nanospider™ technology, an electrospinning method which enables the production of nanofibers at an industrial scale. The ßG was selected as active ingredient based on its confirmed wound healing potential in both animals and humans. Hydroxypropyl methylcellulose (HPMC) and polyethylene oxide (PEO) were included as copolymers. Rheological profiles of spinning solutions containing HPMC, PEO, ßG, ethanol and water, were optimized. The nanofiber formation was confirmed by Field Emission Scanning Electron Microscopy (FE-SEM), and both nanofibers with (ßG-nanofibers) or without ßG (NoßG-nanofibers) were evaluated by their swelling index and FT-IR spectroscopy. The formulations, active ingredient and excipients were tested for their possible in vitro toxicity in keratinocytes. Finally, the wound healing potential of the nanofibers was tested in externally induced excisional wounds in male diabetic db/db mice. Three different doses of ßG-nanofibers and the ßG-free, NoßG-nanofibers, were evaluated for their in vivo wound healing efficacy. All nanofiber-treatments provided improved wound healing as compared to the negative control (water). All ßG-nanofiber treated groups exhibited significantly improved wound healing as compared to the NoßG-nanofiber treated group, indicating the potential of ßG-nanofibers as wound dressing.

Sprayable Carbopol hydrogel with soluble beta-1,3/1,6-glucan as an active ingredient for wound healing - Development and in-vivo evaluation.

Chronic wounds represent a significant health problem worldwide. There is a need for advanced- and cost-efficient wound healing products able to increase patient comfort and reduce the healing time. The aim of this study was to develop a sprayable hydrogel dressing with beta-glucan (ßG) as the active ingredient, targeting future application in the treatment of both chronic and burn wounds. The ßG was chosen as an active ingredient because of its promising wound healing capabilities, whereas Carbopol 971P NF (Carbopol) was chosen as the thickening agent in the formulation due to several attractive characteristics such as its low viscosity, low toxicity, high transparency and good ion tolerance. Four different hydrogel formulations were prepared with varying Carbopol concentrations. The higher Carbopol concentration, 0.5% (w/w), was used to prepare three formulations comprising the HighCP:NoßG, HighCP:LowßG and the HighCP:MediumßG formulation, respectively. Lower Carbopol concentration, 0.25% (w/w), was used to prepare the LowCP:HighßG formulation. The content of ßG varied from 0.25% in the HighCP:LowßG, 0.5% in the HighCP:MediumßG and 1.0% (w/w) in the LowCP:HighßG formulation, respectively. The first part of the study focused on the rheological characterization of the hydrogels and the fluid affinity testing. All formulations were confirmed to be stable gels; the ßG was shown to augment the gel strength by increasing the yield strength of the gel in a dose dependent manner. The stability of the formulations containing either Carbopol alone or in a combination with ßG did not deteriorate over 26weeks, and the fluid donation and absorption study indicated a fluid donation profile, which favors healing of dry wounds. The in vivo efficacy of the formulations, evaluated in the modified diabetic male mice (db/db mice), showed that Carbopol alone was unable to induce improved healing and caused adverse reactions in some wounds. The inclusion of ßG increased the epithelialization and wound contraction in the db/db mice when given at high ßG:Carbopol ratio. The positive effect of ßG was, however, not sufficient to counteract the adverse effect of Carbopol, thus a more suitable thickening agent should be investigated for further development of a sprayable wound care product.

The effect of soluble beta-1,3-glucan and lipopolysaccharide on cytokine production and coagulation activation in whole blood.

Soluble beta-1,3-glucan has been demonstrated to protect against infection and shock in rats and mice, and clinical studies suggest that administration of soluble glucans to trauma/surgical patients decreases septic complications and improves survival. However, little is known about the precise mechanisms by which glucans influence the state of activation of blood cells, which are responsible for the fulminant cytokine production and the activation of the coagulation system observed in serious gram-negative infection. We studied therefore the effect of an underivatized, soluble yeast beta-1,3-glucan and lipopolysaccharide (LPS), either alone or in combination, on tumor necrosis factor-alpha (TNFalpha), interleukin-6 (IL-6), IL-8 and IL-10 secretion and monocyte tissue factor (TF) expression in human whole blood. As expected, LPS induced the secretion of substantial amounts of all measured parameters, whereas only minor amounts of TNFalpha, IL-6, and IL-10 were induced by beta-glucan itself. However, beta-glucan itself induced the production of significant amounts of IL-8 and TF. Soluble beta-1,3-glucan had a strong synergistic effect on the LPS-induced secretion of IL-8, IL-10, and on monocyte TF activity, but not on TNFalpha and 1L-6 production. On the other hand, soluble beta-glucan strongly primed LPS stimulation of all parameters, including TNFalpha and IL-6. beta-Glucan also induced detectable neutrophil degranulation within 15 min, whereas a response to LPS was first detected after 90 min. In conclusion, soluble beta-1,3-glucan upregulated leukocyte activity, both on its own and in concert with LPS.