Rolf E. Engstad

The effect of soluble β-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.

Macrophage stimulating agent soluble yeast β‐1,3/1,6‐glucan as a topical treatment of diabetic foot and leg ulcers: A randomized, double blind, placebo‐controlled phase II study

Dysregulated inflammatory response is believed to be an important factor in the pathogenesis of several late complications of diabetes mellitus. β‐Glucans are potent inducers of immune function. The present randomized, double blind, two‐center, placebo‐controlled study was undertaken to explore safety, tolerability and efficacy of soluble β‐1,3/1,6‐glucan (SBG) as a local treatment of diabetic foot ulcers.

Dectin-1 plays a redundant role in the immunomodulatory activities of β-glucan-rich ligands in vivo

β-Glucans are known for their ability to trigger both protective and damaging immune responses. Here we have explored the role of the beta-glucan receptor Dectin-1 in archetypical models of protective and non-protective immunomodulation induced by beta-glucan rich ligands. In the first model, we explored the role of Dectin-1 in the ability of soluble purified β-glucans to mediate protection against systemic Staphylococcus aureus infection in mice. In the second model, we explored the role of Dectin-1 in zymosan induced multiple organ dysfunction syndrome. In both cases, these β-glucan rich compounds had marked effects in vivo which were unaltered by Dectin-1 deficiency, suggesting that this receptor has a redundant role in these murine models.

Cardioprotective effect of pretreatment with b-glucan in coronary artery bypass grafting

Background. β-glucan pretreatment has been shown to attenuate inflammatory response and to protect against ischemia-reperfusion injury in animal studies. The aims of the present study were to examine the safety of pretreatment with β-1,3/1,6-glucan in patients scheduled for coronary artery bypass grafting (CABG), and to investigate whether β-1,3/1,6-glucan pretreatment could suppress inflammatory response and protect against ischemia-reperfusion injury following CABG. Methods. Twenty one patients scheduled for CABG were assigned to oral β-1,3/1,6-glucan 700 mg (Group 1) or 1 400 mg (Group 2) five consecutive days before surgery and were compared with a control group (Group 3). Blood samples were drawn preoperatively and on the first, third and fifth postoperative day for analysis of acute-phase reactants, hematology, cytokines and myocardial enzymes. Results. The study drug was well tolerated. Creatine kinase isoenzyme MB was significantly lower in Group 2 compared with controls on the first postoperative day (p = 0.028). Mean change in cardiac troponin T was lower in Group 2 compared with controls (p = 0.028). Conclusions. β-1,3/1,6-glucan pretreatment is safe in patients undergoing CABG and may protect against ischemia reperfusion injury following CABG.

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

Abstract 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 (&bgr;G) as the active ingredient, targeting future application in the treatment of both chronic and burn wounds. The &bgr;G 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:No&bgr;G, HighCP:Low&bgr;G and the HighCP:Medium&bgr;G formulation, respectively. Lower Carbopol concentration, 0.25% (w/w), was used to prepare the LowCP:High&bgr;G formulation. The content of &bgr;G varied from 0.25% in the HighCP:Low&bgr;G, 0.5% in the HighCP:Medium&bgr;G and 1.0% (w/w) in the LowCP:High&bgr;G 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 &bgr;G 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 &bgr;G did not deteriorate over 26 weeks, 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 &bgr;G increased the epithelialization and wound contraction in the db/db mice when given at high &bgr;G:Carbopol ratio. The positive effect of &bgr;G 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. Graphical abstract Figure. No Caption available.

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

&NA; The increased prevalence of chronic wounds requires novel treatment options. The aim of this study was to develop a beta‐glucan (&bgr;G)‐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 &bgr;G 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, &bgr;G, ethanol and water, were optimized. The nanofiber formation was confirmed by Field Emission Scanning Electron Microscopy (FE‐SEM), and both nanofibers with (&bgr;G‐nanofibers) or without &bgr;G (No&bgr;G‐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 &bgr;G‐nanofibers and the &bgr;G‐free, No&bgr;G‐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 &bgr;G‐nanofiber treated groups exhibited significantly improved wound healing as compared to the No&bgr;G‐nanofiber treated group, indicating the potential of &bgr;G‐nanofibers as wound dressing. Graphical abstract Figure. No caption available.