Design of a Modern Liposome and Bee Venom Formulation for the Traditional VIT-Venom Immunotherapy

Abstract

Traditional venom immunotherapy uses injections of whole bee venom in buffer or adsorbed in Al (OH) 3 in an expensive, time-consuming way. New strategies to improve the safety and efficacy of this treatment with a reduction of injections would, therefore, be of general interest. It would improve patient compliance and provide socio-economic benefits. Liposomes have a long tradition in drug delivery because they increase the therapeutic index and avoid drug degradation and secondary effects. However, bee venom melittin (Mel) and phospholipase (PLA 2 ) destroy the phospholipid membranes. Our central idea was to inhibit the PLA 2 and Mel activities through histidine alkylation and or tryptophan oxidation (with pbb, para-bromo-phenacyl bromide, and/or NBS-N-bromosuccinimide, respectively) to make their encapsulations possible within stabilized liposomes. We strongly believe that this formulation will be nontoxic but immunogenic. In this paper, we present the whole bee venom conformation characterization during and after chemical modification and after interaction with liposome by ultraviolet, circular dichroism, and fluorescence spectroscopies. The PLA 2 and Mel activities were measured indirectly by changes in turbidity at 400 nm , rhodamine leak-out, and hemolysis. The native whole bee venom (BV) presented 78.06% of a-helical content. The alkylation (A-BV) and succynilation (S-BV) of BV increased 0.44 and 0.20% of its a-helical content. The double-modified venom (S-A-BV) had a 0.74% increase of a-helical content. The BV chemical modification induced another change on protein conformations observed by Trp that became buried with respect to the native whole BV. It was demonstrated that the liposomal membranes must contain pbb (SPC:Cho:pbb, 26:7:1) as a component to protect them from aggregation and/or fusion. The membranes containing pbb maintained the same turbidity (100%) after incubation with modified venom, in contrast with pbb-free membranes that showed a 15% size decrease. This size decrease Journal of Liposome Research Downloaded from informahealthcare.com by University of Melbourne on 11/17/14 For personal use only.354 Silva et al. was interpreted as membrane degradation and was corroborated by a 50% rhodamine leak-out. Another fact that confirmed our interpretation was the observed 100% inhibition of the hemolytic activity after venom modification with pbb and NBS (S-A-BV). When S-A-BV interacted with liposomes, other protein conformational changes were observed and characterized by the increase of 1.93% on S-A-BV a-helical content andthe presence of tryptophan residues in a more hydrophobic environment. In other words, the S-A-BV interacted with liposomal membranes, but this interaction was not effective to cause aggregation, leak-out, or fusion. A stable formulation composed by S-A-BV encapsulated within liposomes composed by SPC:Cho:pbb, at a ratio of 26:7:1, was devised. Large unilamellar vesicles of 202.5 nm with a negative surface charge (-24.29 mV) encapsulated 95% of S-A-BV. This formulation ca...

Anaphylaxis: past, present and future

“…Future directions should include initiation of randomized, placebo‐controlled studies comparing new methods of desensitization to existing strategies. These include modification of allergen dose or extract (145), addition of biologic modifiers to reduce side‐effects (146), and exploring new routes of delivery (147). Finally, given the disparities in anaphylaxis management at the level of physicians, patients and the community, new laws, guidelines and educational programs addressing these gaps, and ensuring appropriate treatment of anaphylaxis should be developed and disseminated among all potential care givers.…”

Bee Venom Within Liposomes Synergistically Inhibit Atopic Dermatitis in Mice

“…BV contains various types of peptides, amines, enzymes, lipids, carbohydrates, and amino acids, and the main ingredients are melittin, apamin, and phosphoripase A2 [31]. BV has been used to treat conditions/diseases since ancient Egypt and ancient China [13]. The effects of BV resulting in the inhibition of inflammation in AD has been studied [32].…”

“…Liposomes are effective drug delivery systems that protect drugs by enclosing them in a phospholipid bilayer to prevent chemical and immunological breakdown, and increase intracellular absorption [11]. In particular, studies of BV liposomes have reported the potential to reduce side effects such as BV anaphylaxis, and increased drug absorption [12,13].…”

Cosmetic Applications of Bee Venom

“…Recently, some formulations such as microspheres (biodegradable polymers) containing lyophilized whole venom, aqueous pure venom, and aluminum hydroxide (Al[OH] 3 )-adsorbed preparations have become available in Europe, whereas in the United States, only the formulated whole-venom preparations are approved [68]. Liposomes have a long tradition in drug delivery because they increase the therapeutic index and avoid drug degradation and secondary effects [69].…”