Wasp venom from Vespa magnifica acts as a neuroprotective agent to alleviate neuronal damage after stroke in rats.

CONTEXT: Acute ischaemic stroke (AIS) is a major cause of disability and death, which is a serious threat to human health and life. Wasp venom extracted from Vespa magnifica Smith (Vespidae) could treat major neurological disorders. OBJECTIVE: This study investigated the effects of wasp venom on AIS in rats. MATERIAL AND METHODS: We used a transient middle cerebral artery occlusion (MCAO) model in Sprague-Dawley rats (260-280 g, n = 8-15) with a sham operation group being treated as negative control. MCAO rats were treated with wasp venom (0.05, 0.2 and 0.6 mg/kg, i.p.) using intraperitoneal injection. After treatment 48 h, behavioural tests, cortical blood flow (CBF), TTC staining, H&E staining, Nissl staining, TUNEL assay, immunohistochemistry (IHC) and ELISA were employed to investigate neuroprotective effects of wasp venom. RESULTS: Compared with the MCAO group, wasp venom (0.6 mg/kg) improved neurological impairment, accelerated CBF recovery (205.6 ± 52.92 versus 216.7 ± 34.56), reduced infarct volume (337.1 ± 113.2 versus 140.7 ± 98.03) as well as BBB permeability as evidenced by changes in claudin-5 and AQP4. In addition, function recovery of stroke by wasp venom treatment was associated with a decrease in TNF-α, IL-1ß, IL-6 and inhibition activated microglia as well as apoptosis. Simultaneously, the wasp venom regulated the angiogenesis factors VEGF and b-FGF in the brain. CONCLUSIONS: Wasp venom exhibited a potential neuroprotective effect for AIS. In the future, we will focus on determining whether the observed actions were due to a single compound or the interaction of multiple components of the venom.

Involvement of the gabaergic, serotonergic and glucocorticoid mechanism in the anxiolytic-like effect of mastoparan-L.

Mastoparan-L (mast-L) is a cell-penetrating tetradecapeptide and stimulator of monoamine exocytosis. In the present study, we evaluated the anxiolytic-like effect of mast-L. Preliminary pharmacological tests were conducted to determine the most appropriate route of administration, extrapolate dose and detect potential toxic effects of this peptide. Oral and intracerebroventricular administration of mast-L (0.1, 0.3 or 0.9 mg.kg-1), diazepam (1 or 5 mg.kg-1), buspirone (10 mg.kg-1) or vehicle 10 mL.kg-1 was carried out prior to the exposure of mice to the anxiety models: open field, light-dark box and elevated plus-maze. To characterize the mechanism underlying the antianxiety-like effect of mast-L, pharmacological antagonism, blood plasma analysis, molecular docking, and receptor binding assays were performed. The absence of a neurotoxic sign, animal's death as well as lack of significant changes in the relative organ weight, hematological and biochemical parameters suggest that mast-L is relatively safe. The anxiolytic-like effect of mast-L was attenuated by flumazenil (antagonist of benzodiazepine binding site) and WAY100635 (selective antagonist of 5-HT1A receptors) pretreatments. Mast-L reduced plasma corticosterone and lowered the scoring function at GABAA -18.48 kcal/mol (Ki = 155 nM), 5-HT1A -22.39 kcal/mol (Ki = 130 nM), corticotropin-releasing factor receptor subtype 1 (CRF1) -11.95 kcal/mol (Ki = 299 nM) and glucocorticoid receptors (GR) -14.69 kcal/mol (Ki = 3552 nM). These data fit the binding affinity (Ki) and demonstrate the involvement of gabaergic, serotonergic and glucocorticoid mechanisms in the anxiolytic-like property of mast-L.

Study of mastoparan analog peptides against Candida albicans and safety in zebrafish embryos (Danio rerio).

Aim: In this work, mastoparan analog peptides from wasp venom were tested against Candida albicans and safety assays were performed using cell culture and model zebrafish. Materials & methods: Minimal inhibitory concentration was determined and toxicity was performed using human skin keratinocyte and embryo zebrafish. Also, permeation of peptides through embryo chorion was performed. Results: The peptides demonstrated anti-C. albicans activity, with low cytotoxicity and nonteratogenicity in Danio rerio. The compounds had different permeation through chorion, suggesting that this occurs due to modifications in their amino acid sequence. Conclusion: The results showed that the studied peptides can be used as structural study models for novel potential antifungal agents.

Changing microRNA Expression during Three-Month Wasp Venom Immunotherapy.

MicroRNAs are small non-coding molecules playing a significant regulatory role in several allergic diseases. However their role in tolerance induction remains unclear. The aim of this study was to determine the expression of selected microRNAs during the first three months of wasp venom immunotherapy (VIT). 5 adult patients with a history of severe systemic reactions after stinging by wasps and confirmed sensitization were included. Venous blood samples were collected before VIT, 24 hours after completing its initial phase and after 3 months of the maintenance therapy. A control group was comprised of 5 healthy individuals with no history of allergy. In the blood samples expression of 96 microRNAs was determined with the use of microfluidic cards. In a statistical analysis the expression was compared between the study groups as well as between the pre- and post-VIT samples. Significant differences were found between the patients with wasp venom allergy and the healthy controls in the expression of miR-601 and miR-1201 upregulated in allergic patients at every time point (p = 0.04; p = 0.015, respectively). During VIT profile of microRNA was changing with lower expression of 6 microRNAs (including miR-182, miR-342, miR-375) and higher of 11 microRNAs (including let-7d, miR-34b, miR-143). To conclude, VIT has led to some changes in the expression of microRNA associated with Th2-type inflammation and tolerance induction.

MRGPR-mediated activation of local mast cells clears cutaneous bacterial infection and protects against reinfection.

Mast cells (MCs) are strategically distributed at barrier sites and prestore various immunocyte-recruiting cytokines, making them ideal targets for selective activation to treat peripheral infections. Here, we report that topical treatment with mastoparan, a peptide MC activator (MCA), enhances clearance of Staphylococcus aureus from infected mouse skins and accelerates healing of dermonecrotic lesions. Mastoparan functions by activating connective tissue MCs (CTMCs) via the MRGPRX2 (Mas-related G protein-coupled receptor member X2) receptor. Peripheral CTMC activation, in turn, enhances recruitment of bacteria-clearing neutrophils and wound-healing CD301b+ dendritic cells. Consistent with MCs playing a master coordinating role, MC activation also augmented migration of various antigen-presenting dendritic cells to draining lymph nodes, leading to stronger protection against a second infection challenge. MCAs therefore orchestrate both the innate and adaptive immune arms, which could potentially be applied to combat peripheral infections by a broad range of pathogens.

Safety and Efficacy of a Progressively Prolonged Maintenance Interval of Venom Immunotherapy.

BACKGROUND: The long-term protection provided by venom immunotherapy (VIT) is related to the dose administered and to its long duration; the latter, however, becomes inconvenient for patients in countries like Greece, with many islanders or inhabitants of distant mountainous areas. Maintenance interval prolongation reduces the number of office visits - saving time and money - and as a consequence contributes to the patients' compliance. The aim of this prospective study was to evaluate the safety and efficacy of VIT on a progressively prolonged maintenance interval (PPMI). METHOD: 450 venom-allergic patients were reviewed for participation in our study; all of them were initially treated with a modified rush or an ultrarush protocol using freshly reconstituted, pure venoms. Upon reaching the maintenance dose, the VIT interval was scheduled to be gradually prolonged - by 1 week each time - aiming at a maximal interval of 26 weeks. RESULTS: 267/450 patients consented to participate in our VIT PPMI protocol: 98 were treated with vespid(s) venom, 142 with honeybee venom, and 27 with both. The mean duration of patient follow-up was 9.1 ± 4.2 years. The majority of systemic reactions due to VIT injections occurred up to the 8-weeks PPMI; few additional reactions were documented in a small fraction (2.9%) of our patient population beyond 9 weeks and up to 16 weeks; all were caused by honeybee VIT. No reactions were observed during VIT administration at the 26-week interval. Ninety-six patients reported 204 field sting occurrences by the culprit insect. Ten systemic reactions (8 mild and 2 moderate in severity) were registered between the 9- and 18-week PPMI; the honeybee was the culprit insect in all cases. 108 field stings by the offending insect were sustained beyond the 20- and up to the 26-week PPMI; there were no reactions at all. CONCLUSIONS: Progressively prolonging the VIT maintenance interval up to 26 weeks appears to be safe and efficacious.

Venom Immunotherapy in High-Risk Patients: The Advantage of the Rush Build-Up Protocol.

BACKGROUND: Venom immunotherapy (VIT) is considered to be the gold standard treatment for patients with hymenoptera venom allergy. This treatment induces systemic reactions (SR) in a significant number of patients. OBJECTIVE: To evaluate the outcome of VIT in patients with known risk factors for VIT-induced SR and to compare rush VIT (RVIT) and conventional VIT (CVIT). METHODS: All of the patients who received VIT and had at least one of the following risk factors were included: current cardiovascular disease, uncontrolled asthma, high basal serum tryptase, current treatment with ß-blockers or angiotensin-converting enzyme inhibitors, and age >70 or <5 years. RESULTS: Sixty-four patients were included, and most of them (52; 81.5%) were allergic exclusively to bee venom. Thirty-five (54.7%) patients underwent RVIT and 29 CVIT. The incidence of patients who developed SR during the build-up phase was similar for RVIT and CVIT (25.7 and 27.5%, respectively; p = 1). However, the incidence of SR per injection was significantly higher in CVIT than in RVIT (5.6 and 2.75%, respectively; p = 0.01). Most reactions (79.1%) were mild, limited to the skin. Most of the patients (92.1%) reached the full maintenance dose of 100 µg. This dose was reached by a significantly larger number of patients receiving RVIT compared to CVIT (100 and 82.7%, respectively; p = 0.01). None of the patients experienced exacerbation of their concurrent chronic disease during VIT. CONCLUSION: VIT can be performed safely and efficiently in patients with risk factors for immunotherapy. In these patients RVIT appears to be safer and more efficient than CVIT.

Which immunotherapy product is better for patients allergic to Polistes venom? A laboratory and clinical study.

BACKGROUND: Venom immunotherapy (VIT) is highly effective in preventing allergic reactions to insect stings, but the appropriate venom must be used to achieve clinical protection. In patients with multiple positive results to venoms, molecular allergy diagnostics or CAP-inhibition may identify the causative venom. Concerning allergy to venom from Polistes spp. it has been proposed that only the European species P. dominulus should be used for VIT. However, this recommendation is not present in any international guideline. Using both laboratory and clinical data, we aimed to evaluate the reliability of this proposal. METHODS: We performed an in vitro study using CAP-inhibition to determine sensitization of 19 patients allergic to Polistes venom. The clinical study included 191 patients with positive tests to Polistes treated with VIT, 102 were treated with P. dominulus and 89 were treated with a mix of American Polistes (mAP). RESULTS: The difference in % of inhibition was significant concerning inhibition of P. dominulus sIgE by P. dominulus venom (79.8%) compared with inhibition by mAP venom (64.2%) and not significant concerning the inhibition of mAP sIgE by P. dominulus venom (80.1%) and by mAP venom (73.6%). Instead, the clinical protection from stings was not statistically different between the two kinds of venom. CONCLUSION: The data from CAP inhibition would suggest that the choice of either P. dominulus venom or mAP venom for VIT is appropriate in patients with CAP inhibition higher than 70%, but the clinical data show the same odds of protection from stings using for VIT P. dominulus or mAP venom.

Changes in the Expression of MicroRNA in the Buildup Phase of Wasp Venom Immunotherapy: A Pilot Study.

BACKGROUND: Allergen-specific immunotherapy is the most effective method of treatment in allergy to wasp venom. However, its mechanism of action is still not fully understood. The aim of this study is to describe changes in microRNA (miRNA) expression in patients undergoing the buildup phase of venom immunotherapy. METHODS: The study group comprised 7 adult patients with a history of severe systemic reactions after stinging by a wasp. In all patients, sensitization to wasp venom had been confirmed by skin tests and serum IgE. The buildup phase of wasp venom immunotherapy (VIT) was conducted according to an ultrarush protocol. In blood samples collected before and 24 h after completing the VIT buildup phase, 740 miRNAs were assessed. RESULTS: Of the 740 miRNAs, 440 were detected in the study group, and in 5 expression was significantly changed after the buildup phase of VIT: miR-370, miR-539, miR-502-3p, miR-299, and miR-29c. Another 62 miRNAs changed 2-fold in some patients (nonsignificant), including increases in miR-143 (stimulating FOXp3 expression) and let-7d (reducing expression of IL-13, IL-6, and TLR4), and decreases in proinflammatory miR-301, miR-146b, miR-106, and miR-485. CONCLUSIONS: Several changes in miRNA expression have been found as a result of the buildup phase of wasp VIT, with lower expression of some miRNAs involved in allergic inflammation and higher expression of those possibly involved in tolerance induction. However, the role of the most significant changes is uncertain.

Antinociceptive properties of the mastoparan peptide Agelaia-MPI isolated from social wasps.

Analgesic therapy is based on the sequential treatment of pain, in which opioids are drugs of last resource and known to be highly effective, but are also responsible for undesirable side effects, tolerance and addiction. There is a need for new drugs with alternative targets in order to minimize side effects and improve treatment efficacy. Mastoparans are an abundant class of peptides in wasp venom and have shown great potential as new drugs, as well as being excellent tools for the study of G-protein-coupled receptors. The objective of this study was to investigate the antinociceptive activity of the mastoparan Agelaia-MP I and the mechanisms involved. Agelaia-MP I (MW 1565 Da) showed dose-dependent antinociceptive activity in mice submitted to i.c.v. injection in two different models. The highest dose produced a maximum effect for up to 4 h, and nociception remained low three days after injection. Further experiments showed that Agelaia-MPI induced partial and reversible blockade of the amplitude of action potential, probably interacting with voltage-gated sodium channels. These results revealed the significant potential impact of compounds isolated from wasp venom on the central nervous system (CNS). In addition, the antinociceptive effect described here is a novel activity for mastoparans.

Safety of Ultrarush Venom Immunotherapy: Comparison Between Children and Adults.

BACKGROUND: The ultrarush protocol is an attractive approach in the buildup phase of venom immunotherapy (VIT-UR). However, the degree of risk of VIT-UR in children remains unknown. The objective of this study was to compare the safety of VIT-UR in children and adults. METHODS: We performed a study based on prospectively gathered medical records of children and adults with hymenoptera venom allergy treated with VIT-UR in 3 allergy centers in Poland. RESULTS: The study population comprised 134 children (mean [SD] age, 12.6 [3.7] years; males, 70.1%) and 207 adults (mean age, 42.4 [14.0] years; males, 47.8%). The number of children in the subgroups of bee venom (BV) allergy and wasp venom (WV) allergy were comparable, although sensitization to WV was more predominant in the adult group (70.1%). Skin reactivity to both venoms was more common in children than in adults (P < .001); however, children had higher concentrations of total IgE and specific IgE to BV (both P < .001). Systemic allergic reactions (VIT-SARs) occurred in 6.2% of the patients (3.7% in children and 7.7% in adults; nonsignificant). In adults, SARs occurred more frequently in patients treated with BV than WV extracts (21.4% vs 2.6%; P < .001). The same pattern was observed in children (7.2% vs 0%; P = .058). However, VIT-SARs to BV were less frequent in children than in adults (P = .034). Similarly, no significant relationship was noted between children and adults receiving WV VIT (2.6% vs 0%; nonsignificant). The severity of VIT-SAR did not differ between children and adults. CONCLUSIONS: VIT-UR is safer in children. Age below 18 is not a risk factor for VIT-SARs.

Pathophysiological effects caused by the venom of the social wasp Synoeca surinama.

Envenomation by wasp stings is a public health preoccupation, and signals after stings have variable effects depending on the number of attacks and individual sensitivities. Even with the high rate of wasp sting cases, the study of phatophysiological effects of the envenomation is still very incipient. In this context, early and accurate assessment of this prognostic can aid in the reduction of the symptomatology and complete remission of the later symptoms. Then, the present study evaluated the toxicological effects caused by envenomation produced by Synoeca surinama, a wasp easily found in Neotropical regions. In vivo tests comprised the evaluation of LD50 (OECD 423), nociception, edema, myotoxic lesion and hemorrhage induction, in vitro tests were realized to evaluate hemolysis, contractile and coagulation alteration. The envenomation effects observed were dose- and time-dependent; the LD50 observed for S. surinama was 178 µg/kg, approximately 17 times more lethal than that of the honeybee. Moreover, a potent algesic and oedema effect, and weak hemorrhagic signal were observed after injection of the venom wasp. Assays in vitro showed that this venom is able to prolong the clotting time of plasma and to increase creatine kinase levels. Our results demonstrated that this venom induced serious local and systemic effects in mammals and, so, to avoid permanent damage to the patient, health professionals should carefully investigate each accident. Moreover, due to its high occurrence in Neotropical regions, ecological management, particularly in areas with free access of children and elderly, should be performed.

Cloning, structural modelling and characterization of VesT2s, a wasp venom hyaluronidase (HAase) from Vespa tropica

Wasp venom is a complex mixture containing proteins, enzymes and small molecules, including some of the most dangerous allergens. The greater banded wasp (Vespa tropica) is well-known for its lethal venom, whose one of the major components is a hyaluronidase (HAase). It is believed that the high protein proportion and activity of this enzyme is responsible for the venom potency. Methods: In the present study, cDNA cloning, sequencing and 3D-structure of Vespa tropica venom HAase were described. Anti-native HAase antibody was used for neutralization assay. Results: Two isoforms, VesT2a and VesT2b, were classified as members of the glycosidase hydrolase 56 family with high similarity (4297 %) to the allergen venom HAase. VesT2a gene contained 1486 nucleotide residues encoding 357 amino acids whereas the VesT2b isoform consisted of 1411 residues encoding 356 amino acids. The mature VesT2a and VesT2b are similar in mass and pI after prediction. They are 39119.73 Da/pI 8.91 and 39571.5 Da/pI 9.38, respectively. Two catalytic residues in VesT2a, Asp107 and Glu109 were substituted in VesT2b by Asn, thus impeding enzymatic activity. The 3D-structure of the VesT2s isoform consisted of a central core (/)7 barrel and two disulfide bridges. The five putative glycosylation sites (Asn79, Asn99, Asn127, Asn187 and Asn325) of VesT2a and the three glycosylation sites (Asn1, Asn66 and Asn81) in VesT2b were predicted. An allergenic property significantly depends on the number of putative N-glycosylation sites. The anti-native HAase serum specifically recognized to venom HAase was able to neutralize toxicity of V. tropica venom. The ratio of venom antiserum was 1:12. Conclusions: The wasp venom allergy is known to cause life-threatening and fatal IgE-mediated anaphylactic reactions in allergic individuals. Structural analysis was a helpful tool for prediction of allergenic properties including their cross reactivity among the vespid HAase.

Rush immunotherapy for wasp venom allergy seems safe and effective in patients with mastocytosis.

BACKGROUND: Patients with mastocytosis and wasp venom allergy (WA) may benefit from venom immunotherapy (VIT). However, fatal insect sting reactions have been described in mastocytosis patients despite previous immunotherapy. We investigated the safety and efficacy of (rush) VIT in patients with mastocytosis and WA. OBJECTIVE: To investigate the safety and efficacy of (rush) VIT in patients with mastocytosis and WA. METHODS: We describe nine patients with cutaneous mastocytosis and WA who received VIT. Cutaneous mastocytosis was confirmed by histopathology and systemic mastocytosis was diagnosed according to World Health Organization criteria. VIT was given according to a rush protocol. Given the difference in safety and efficacy of VIT in patients with WA and honeybee venom allergy, we reviewed the literature for VIT with the focus on WA patients with mastocytosis and addressed the difference between patients with cutaneous versus systemic mastocytosis. RESULTS: Nine patients had WA and mastocytosis, of whom six had cutaneous mastocytosis, two combined cutaneous and systemic mastocytosis and one systemic mastocytosis. All patients received rush IT with wasp venom. Most patients had only mild local side effects, with no systemic side effects during the course of VIT. One patient had a systemic reaction upon injection on one occasion, during the updosing phase, with dyspnoea and hypotension, but responded well to treatment. Immunotherapy was continued after temporary dose adjustment without problems. Two patients with a previous anaphylactic reaction were re-stung, without any systemic effects. CONCLUSIONS: VIT is safe in cutaneous mastocytosis patients with WA, while caution has to be made in case of systemic mastocytosis. VIT was effective in the patients who were re-stung.

Delivering wasp venom for cancer therapy.

Cytolytic peptides with potential therapeutic properties have appeared during the last three decades. However, the use of these natural weapons is relatively narrow due to their non-specific cytolytic activity as well as their rapid degradation and excretion when injected in blood. In order to rescue the use of these lytic peptides, we have designed pro-cytotoxic systems based on cytotoxic peptides conjugated to poly(l-glutamic acid) PGA polymer through specific cleavage sequences that are sensitive over-expressed tumor proteases, such as the metalloproteinase-2 (MMP-2) or cathepsin B. The potent cytotoxic peptide tested here, Mitoparan, is inactive when conjugated to the polymer and then become active again once released through the tumor proteases. Furthermore, this pro-cytotoxic system was decorated by a particular targeting peptide which binds to HER2 receptors over-expressed in some types of breast tumor cells, thereby increasing the selective release of cytolytic peptides inside tumor cell with exquisite spatiotemporal control. In this way, the system would improve the maximum tolerated dose and the pharmacokinetic parameters of cytotoxic peptides in vivo.

Risk assessment of Hymenoptera re-sting frequency: implications for decision-making in venom immunotherapy.

BACKGROUND: Venom immunotherapy is highly efficacious in preventing anaphylactic sting reactions. However, there is an ongoing discussion regarding patient selection and whether and how to apply a cost-benefit analysis of venom immunotherapy. In order to help decision-making, we investigated the re-sting frequency of hymenoptera-venom-allergic patients to single out those at high risk. METHODS: In this retrospective study, re-sting data of 96 bee-venom-allergic patients and 95 vespid-venom-allergic patients living mainly in a rural area of Switzerland were analyzed. Hymenoptera venom allergy status was rated according to the classification system of H.L. Mueller [J Asthma Res 1966;3:331-333]. Different risk-groups were defined according to sting exposure and their median sting-free interval was calculated. RESULTS: The risk factors for a wasp or bee re-sting were outdoor occupation, beekeeping and habitation close to a bee-house. Half of all vespid-venom-allergic outdoor workers were re-stung within 3.75 years compared to 7.5 years for indoor workers. Similarly, 50% of the bee-venom-allergic beekeepers or subjects with a bee-house in the vicinity suffered a bee re-sting within 5.25 years compared to 10.75 years for individuals who were not beekeepers. CONCLUSIONS: The high degree of exposure of vespid-venom-allergic outdoor workers and bee-venom-allergic beekeepers and subjects living close to bee-houses underlines the high benefit of venom immunotherapy for these patients even if they suffered a non-life-threatening grade II reaction. Yet, bee-venom-allergic individuals with no proximity to bee-houses and with an indoor occupation face a very low exposure risk, which justifies epinephrine rescue treatment for these patients especially if they have suffered from grade II sting reactions.