Isolation and characterization of an anti-leishmanial disintegrin from Cerastes cerastes venom.

Investigating new antimicrobial and antiparasitic components from Viperidae venoms represents an alternative therapeutic strategy. In this study, we report the characterization of a disintegrin isolated from Cerastes cerastes venom, exhibiting antiparasitic activity on Leishmania infantum promastigotes. Indeed, isolated disintegrin, referred to Disintegrin_Cc, induced 84.75% of parasiticidal activity and deep morphological alterations on the parasites. SDS-PAGE analysis indicated that this disintegrin was homogenous. This dimeric disintegrin of 14,193.97 Da contains an RGD domain and four intramolecular disulfide bridges. It presents a high percentage of identity with other related snake disintegrins. Predicted 3D structure indicated that this peptide shares partial homology with well-known active antimicrobial peptides. Disintegrin_Cc inhibited 80% of arachidonic acid-induced platelet aggregation. The obtained results suggest that the isolated molecule plays a dual role as a disintegrin and as an anti-leishmanial compound. This component could be useful as a drug in the treatment of leishmaniasis.

Biochemical and biological characterization of a dermonecrotic metalloproteinase isolated from Cerastes cerastes snake venom.

A dermonecrotic metalloproteinase (CcD-II) was isolated from C. cerastes venom. Venom fractionation was performed using three chromatographic steps (molecular exclusion on Sephadex G-75, ion-exchange on DEAE-Sephadex A-50, and reversed-phase high-performance liquid chromatography on C8 column). CcD-II presented an apparent molecular mass of 39.9 kDa and displayed a dermonecrotic activity with a minimal necrotic dose of 0.2 mg/kg body weight. CcD-II showed proteolytic ability on casein chains and on α and ß fibrinogen chains that was inhibited by ethylenediamine tetraacetic acid and 1,10-phenanthroline while remained unaffected by phenylmethylsulphonyl fluoride and heparin. CcD-II displayed gelatinase activity and degraded extracellular matrix compounds (type-IV collagen and laminin). These results correlated with histopathological analysis showing a complete disorganization of collagenous skin fibers. These data suggested that CcD-II belongs to P-II class of snake venom metalloproteinase. The characterization of venom compounds involved in tissue damage may contribute in the development of new therapeutic strategies in envenomation.

Pathophysiological effects of Cerastes cerastes and Vipera lebetina venoms: Immunoneutralization using anti-native and anti-(60)Co irradiated venoms.

Cerastes cerastes and Vipera lebetina are the most medically important vipers in Algeria. Their bite induces several pathological effects on victims of accidental envenomation. In this study we analyzed the pathogenesis induced after an experimental envenomation. Indeed, we determined, in vitro, venom enzymatic activities and we analyzed, in vivo, pathological effects induced on liver, heart, lung and skin. In addition we investigated the neutralizing potency of four experimental antivenoms elicited against native and irradiated venoms. Results revealed that V. lebetina and Cerastes cerastes venoms presented strong hemorrhagic, oedematic and necrotic activities. Histopathological study showed that both venoms induced deep damage in tissue structures leading to organ dysfunction. They also increased cellular peroxidases activities, indicating an inflammatory process that is known to amplify tissue damage. Western-blot analysis evidenced that anti-irradiated venoms recognized most components of native venoms. Antivenoms were effective in neutralizing all tested activities, with an increased protective effect obtained with anti-irradiated venoms. Anti-irradiated venoms reduced cellular peroxidases activities indicating a reduction of the inflammatory response. These results may improve our understanding of Algerian Viperidae bite pathogenesis and would encourage further studies planning to provide more proofs on the effectiveness of anti-irradiated venoms administration in the treatment of envenomation.

Therapeutic outcome of quercetin nanoparticles on Cerastes cerastes venom-induced hepatorenal toxicity: a preclinical study.

Aim: The objective of this study was to investigate the therapeutic potential of quercetin (QT) and QT-loaded poly(lactic-co-glycolic acid) nanoparticles (QT-NPs) on Cerastes cerastes venom-mediated inflammation, redox imbalance, hepatorenal tissue damage and local hemorrhage. Methods: The developed QT-NPs were first submitted to physicochemical characterization and then evaluated in the 'challenge then treat' and 'preincubation' models of envenoming. Results: QT-NPs efficiently alleviated hepatorenal toxicity, inflammation and redox imbalance and significantly attenuated venom-induced local hemorrhage. Interestingly, QT-NPs were significantly more efficient than free QT at 24 h postenvenoming, pointing to the efficacy of this drug-delivery system. Conclusion: These findings highlight the therapeutic potential of QT-NPs on venom-induced toxicity and open up the avenue for their use in the management of snakebite envenoming.

Therapeutic Outcome of Anti-inflammatory and Antioxidative Medicines on the Dermonecrotic Activity of Cerastes cerastes Venom.

Envenomation by Cerastes cerastes often results in local dermonecrotic lesions. While immunotherapy is effective in reversing systemic symptoms, this strategy remains deficient in counteracting the extended dermonecrosis induced from the bite site. In this study, the therapeutic effect of pharmacological drugs on the dermonecrotic activity of the venom was investigated. Venom administration caused a marked dermonecrotic lesion with increased levels of oxidative stress biomarkers (MPO, EPO, NO, H2O2, MDA, protein carbonyl, and thiol levels). Antioxidant capacity was decreased, as evidenced by reduced catalase, glutathione, and selenium levels. Histopathological analysis of skin biopsies revealed necrotic lesions accompanied by hemorrhage and epidermis thickening. The efficiency of cyproheptadine (C), dexamethasone (D), and tetracycline (T), as a monotherapy or in association, were evaluated on the dermonecrotic activity of the venom. Most of the treatments (CD, CT, DT, and CDT) largely reduced tissue necrosis to, respectively, 84.29, 87.83, 83.77, and 82.71% and significantly decreased MPO and EPO activities and NO, H2O2, MDA, and protein carbonyl levels in skin tissue homogenates. CT and CDT associations significantly increased the antioxidant status as indicated by enhanced catalase, glutathione, and selenium levels. The second challenge of the pharmacological associations was more effective in improving the oxidative/antioxidative balance. Skin tissue sections from treated animals with CT or CDT revealed tissue structure close to that observed in control animals. Therefore, the synergistic action of all tested drugs on the major pathways of inflammation (phospholipases A2, metalloproteinases, and histamine) seems to be efficient to neutralize the necrotic activity of the venom.

Myotoxicity induced by Cerastes cerastes venom: Beneficial effect of heparin in skeletal muscle tissue regeneration.

Myonecrosis is a relevant tissue damage induced by snakes of Viperidae family often leading to permanent tissue and function loss and even amputation. The aim of this study was to evaluate the effect of heparin on skeletal muscle tissue regeneration after Cerastes cerastes envenomation. Mice received either the venom (1 LD50) by i.m. route, or the venom followed, by heparin administration by i.v. route at 15 min and 4 h. Obtained results showed that Cerastes cerastes venom induced deep tissue structure alterations, characterized mainly by edema, hemorrhage, myonecrosis and inflammation. Myotoxicity was correlated with increased CK levels in sera, concomitant with their decrease in muscle tissue homogenates. Muscle wet weight was restored within 2 weeks after heparin treatment and 28 days in the envenomed group. Heparin treatment significantly decreased MPO activity, suggesting an anti-inflammatory effect. NO, HGF, VEGF and G-CSF levels were increased after heparin administration. These mitogenic factors constitute potent stimuli for satellite and endothelial cells improving, thus, muscle regeneration. This study showed that muscle tissue recovery was significantly enhanced after heparin treatment. Heparin use seems to be a promising therapeutic approach after viper envenomation.

Irradiated Cerastes cerastes venom as a novel tool for immunotherapy.

Immunotherapy is the most effective treatment for the snake bites. The antivenoms are commonly obtained by hyperimmunization of animals that suffer from venom toxicity. The present report describes gamma irradiation effects on Cerastes cerastes venom. Doses of 1 kGy and 2 kGy gamma radiations were used for venom detoxification. These treated venoms did not have any residual lethal effects until 10 LD(50). Immunological analysis of sera raised against native and irradiated venoms, showed that elicited antibodies to irradiated venoms were able to recognize native venom. Anti-2 kGy irradiated venom had more protective ability than anti-native venom, as tested in mice.

Oral delivery of insulin from alginate/chitosan crosslinked by glutaraldehyde.

Insulin is mainly administered via subcutaneous route by injection which is the cause of painful and possible infections. Oral insulin administration would present a more convenient form of application because it is less invasive. Oral delivery of insulin to the gastrointestinal tract is one of the most challenging issues, because it numerous barriers to overcome in order to create an effective system for insulin delivery. In the present study, insulin-loaded alginate/chitosan blend gel beads were prepared with different mass ratios. Chitosan was depolymerized by gamma irradiation at a dose of 80 kGy reducing its molecular weight for ideal blend with sodium alginate. The homogeneous solution of alginate and chitosan was dripped into CaCl2 solution (2%), the resultant calcium crosslinked beads were dipped in glutaraldehyde (2%) solution sequentially to prepare dual crosslinked beads with improved mechanical properties so as to withstand the simulated gastric fluid (SGF) and simulated intestinal fluid (SIF). Morphological structure, FTIR analysis, thermogravimetry analysis, specific surface area, gel fraction, swelling kinetics in SGF and SIF, loading efficiency, insulin release behavior, mucoadhesivity of the alginate/chitosan beads were investigated. The cumulative insulin release of pure alginate beads (10:0) reached as maximum level 100% in 3h after they were dipped in SIF. Concerning the beads Alg/Chi (8:2), Alg/Chi (7:3) and Alg/Chi (6:4) the cumulative release of insulin reached 90.5%, 89.2% and 70.2%, respectively in 6h. The rate of 100% was reached after 24h for Alg/Chi (8:2), Alg/Chi (7:3) and after 73 h for Alg/Chi (6:4). The presence of chitosan in the blend beads decreased the cumulative insulin release in gastric media and enhanced behavior of alginate/chitosan beads in intestinal medium due to the crosslinking. The alginate/chitosan beads crosslinked by glutaraldehyde may be considered as potential insulin carriers for oral drug delivery system.