Niosomas encapsulados en praziquantel contra Schistosoma mansoni con sensibilidad reducida al praziquantel

Introduction: Praziquantel (PZQ) is the only commercially available drug for schistosomiasis. The current shortage of alternative effective drugs and the lack of successful preventive measures enhance its value. The increase in the prevalence of PZQ resistance under sustained drug pressure is, therefore, an upcoming issue. Objectives: To overcome the tolerance to PZQ using nanotechnology after laboratory induction of a Schistosoma mansoni (S. mansoni) isolate with reduced sensitivity to the drug during the intramolluscan phase. Materials and methods: Shedding snails were treated with PZQ doses of 200 mg/kg twice/week, followed by an interval of one week, and then repeated twice in the same manner. The success of inducing reduced sensitivity was confirmed in vitro via the reduction of cercarial response to PZQ regarding their swimming activity and death percentage at different examination times. Results: Oral treatment with a single PZQ dose of 500 mg/kg in mice infected with cercariae with reduced sensitivity to PZQ revealed a non-significant reduction (35.1%) of total worm burden compared to non-treated control mice. Orally inoculated PZQ-encapsulated niosomes against S. mansoni with reduced sensitivity to PZQ successfully regained the pathogen’s sensitivity to PZQ, as evidenced by measuring different parameters in comparison to the non-treated infected animals with parasites with reduced sensitivity to PZQ. The mean total worm load was 1.33 ± 0.52 with a statistically significant reduction of 94.09% and complete eradication of male worms. A remarkable increase in the percentage reduction of tissue egg counts in the liver and intestine (97.68% and 98.56% respectively) was obtained associated with a massive increase in dead eggs and complete absence of immature stages. Conclusion: PZQ-encapsulated niosomes restored the drug sensitivity against laboratory-induced S. mansoni adult worms with reduced sensitivity to PZQ.Introducción. El praziquantel (PZQ) es el único fármaco disponible comercialmente para la esquistosomiasis. La escasez actual de medicamentos alternativos eficaces y la falta de medidas preventivas eficaces aumentan su valor. El aumento de la prevalencia de la resistencia al PZQ bajo una presión prolongada del fármaco es, por tanto, un tema emergente. Objetivos. Superar la tolerancia a PZQ mediante nanotecnología después de la inducción en laboratorio de un aislamiento de Schistosoma mansoni (S. mansoni) con sensibilidad reducida al fármaco durante la fase intramolusca. Material y métodos. Los caracoles que liberaban cercarias se trataron con dosis de PZQ de 200 mg / kg dos veces por semana, seguido de un intervalo de una semana, y luego se repitieron dos veces de la misma manera. El éxito de inducir una sensibilidad reducida se confirmó in vitro mediante la reducción de la respuesta de las cercarias al PZQ con respecto a su actividad de natación y el porcentaje de muerte en diferentes momentos de examen. Resultados. El tratamiento oral con una dosis única de PZQ de 500 mg / kg en ratones infectados con cercarias con sensibilidad reducida a PZQ reveló una reducción no significativa (35,1%) de la carga total de gusanos en comparación con los ratones de control no tratados. Los niosomas encapsulados en PZQ inoculados por vía oral contra S. mansoni con sensibilidad reducida a PZQ permitieron reestablecer con éxito la sensibilidad del patógeno a PZQ, como lo demuestra la medición de diferentes parámetros en comparación con los animales infectados no tratados con parásitos con sensibilidad reducida a PZQ. La carga media total de gusanos fue de 1,33 ± 0,52 con una reducción estadísticamente significativa del 94,09% y la erradicación completa de los gusanos machos adultos. Se obtuvo un aumento notable en el porcentaje de reducción del recuento de huevos en tejido en el hígado y el intestino (97,68% y 98,56% respectivamente) asociado con un aumento masivo de huevos muertos y ausencia total de estadios inmaduros. Conclusión. Los niosomas encapsulados en PZQ restauraron la sensibilidad al fármaco contra gusanos adultos de S. mansoni inducidos en laboratorio con sensibilidad reducida a PZQ

Nano-Encapsulated Melatonin: A Promising Mucosal Adjuvant in Intranasal Immunization against Chronic Experimental <i>T. gondii</i> Infection

Melatonin (MLT) is now emerging as one of the universally accepted immunostimulators with broad applications in medicine. It is a biological manipulator of the immune system, including mucosal ones. MLT was encapsulated in solid lipid nanoparticles (SLNs), then 100 mg/kg/dose of MLT-SLNs was used as an adjuvant of Toxoplasma lysate antigen (TLA). Experimental mice were intra-nasally inoculated with three doses of different regimens every two weeks, then challenged with 20 cysts of T. gondii Me49 strain, where they were sacrificed four weeks post-infection. Protective vaccine efficacy was evident via the significant brain cyst count reduction of 58.6%, together with remarkably high levels of humoral systemic and mucosal anti-Toxoplasma antibodies (Ig G, Ig A), supported by a reduced tachyzoites invasion of Vero cells in vitro upon incubation with sera obtained from these vaccinated mice. A cellular immune response was evident through the induction of significant levels of interferon-gamma (IFN γ), associated with morphological deteriorations of cysts harvested from the brains of vaccinated mice. Furthermore, the amelioration of infection-induced oxidative stress (OS) and histopathological changes were evident in mice immunized with TLA/MLT-SLNs. In conclusion, the present study highlighted the promising role of intranasal MLT-SLNs as a novel mucosal adjuvant candidate against chronic toxoplasmosis

Nano-Encapsulated Antioxidant: Retinoic Acid as a Natural Mucosal Adjuvant for Intranasal Immunization against Chronic Experimental Toxoplasmosis

The tight relationship between immunity and retinoid levels provides evidence on the critical role of retinoic acid (RA) in regulating immune activity, especially the mucosal one. Mucosal immune response is the key for determination of the outcome of infection, particularly against intracellular mucosal pathogens such as Toxoplasma gondii, where it plays a crucial role as a sentinel against parasite invasion. Herein, the immunomodulatory adjuvant role of RA was evaluated for prophylactic vaccination against chronic Toxoplasma infection. A quantity of 15 µg of RA pre-encapsulated with lipid-based nanoparticles (SLNs) was intranasally used in three doses, two weeks apart, as an adjuvant to the Toxoplasma lysate antigen (TLA). Afterward, mice were infected with 20 cysts of T. gondii (ME49 strain) and were sacrificed at the 4th week post-infection. Parasitological, immunological, biochemical, and histopathological studies were applied as vaccine efficacy measures. The protective role of the tested vaccine was noted using the statistically marked reduction in brain cyst count, accompanied by remarkable levels of protective IFN-γ and antibodies, with amelioration of infection-induced oxidative stress and brain pathology. Ultimately, this experiment outlined the prospective role of a novel, natural, nano-encapsulated and mucosal vaccine adjuvant RA-SLNs as a propitious candidate against chronic toxoplasmosis

Nano-Encapsulated Antioxidant: Retinoic Acid as a Natural Mucosal Adjuvant for Intranasal Immunization against Chronic Experimental Toxoplasmosis

The tight relationship between immunity and retinoid levels provides evidence on the critical role of retinoic acid (RA) in regulating immune activity, especially the mucosal one. Mucosal immune response is the key for determination of the outcome of infection, particularly against intracellular mucosal pathogens such as Toxoplasma gondii, where it plays a crucial role as a sentinel against parasite invasion. Herein, the immunomodulatory adjuvant role of RA was evaluated for prophylactic vaccination against chronic Toxoplasma infection. A quantity of 15 &micro;g of RA pre-encapsulated with lipid-based nanoparticles (SLNs) was intranasally used in three doses, two weeks apart, as an adjuvant to the Toxoplasma lysate antigen (TLA). Afterward, mice were infected with 20 cysts of T. gondii (ME49 strain) and were sacrificed at the 4th week post-infection. Parasitological, immunological, biochemical, and histopathological studies were applied as vaccine efficacy measures. The protective role of the tested vaccine was noted using the statistically marked reduction in brain cyst count, accompanied by remarkable levels of protective IFN-&gamma; and antibodies, with amelioration of infection-induced oxidative stress and brain pathology. Ultimately, this experiment outlined the prospective role of a novel, natural, nano-encapsulated and mucosal vaccine adjuvant RA-SLNs as a propitious candidate against chronic toxoplasmosis

Miltefosine Lipid Nanocapsules for Single Dose Oral Treatment of Schistosomiasis Mansoni: A Preclinical Study.

Miltefosine (MFS) is an alkylphosphocholine used for the local treatment of cutaneous metastases of breast cancer and oral therapy of visceral leishmaniasis. Recently, the drug was reported in in vitro and preclinical studies to exert significant activity against different developmental stages of schistosomiasis mansoni, a widespread chronic neglected tropical disease (NTD). This justified MFS repurposing as a potential antischistosomal drug. However, five consecutive daily 20 mg/kg doses were needed for the treatment of schistosomiasis mansoni in mice. The present study aims at enhancing MFS efficacy to allow for a single 20mg/kg oral dose therapy using a nanotechnological approach based on lipid nanocapsules (LNCs) as oral nanovectors. MFS was incorporated in LNCs both as membrane-active structural alkylphospholipid component and active antischistosomal agent. MFS-LNC formulations showed high entrapment efficiency (EE%), good colloidal properties, sustained release pattern and physical stability. Further, LNCs generally decreased MFS-induced erythrocyte hemolytic activity used as surrogate indicator of membrane activity. While MFS-free LNCs exerted no antischistosomal effect, statistically significant enhancement was observed with all MFS-LNC formulations. A maximum effect was achieved with MFS-LNCs incorporating CTAB as positive charge imparting agent or oleic acid as membrane permeabilizer. Reduction of worm load, ameliorated liver pathology and extensive damage of the worm tegument provided evidence for formulation-related efficacy enhancement. Non-compartmental analysis of pharmacokinetic data obtained in rats indicated independence of antischistosomal activity on systemic drug exposure, suggesting possible gut uptake of the stable LNCs and targeting of the fluke tegument which was verified by SEM. The study findings put forward MFS-LNCs as unique oral nanovectors combining the bioactivity of MFS and biopharmaceutical advantages of LNCs, allowing targeting via the oral route. From a clinical point of view, data suggest MFS-LNCs as a potential single dose oral nanomedicine for enhanced therapy of schistosomiasis mansoni and possibly other diseases

Can antibody conjugated nanomicelles alter the prospect of antibody targeted therapy against schistosomiasis mansoni?

BackgroundCLA (conjugated linoleic acid)-mediated activation of the schistosome tegument-associated sphingomyelinase and consequent disruption of the outer membrane might allow host antibodies to access the apical membrane antigens. Here, we investigated a novel approach to enhance specific antibody delivery to concealed surface membrane antigens of Schistosoma mansoni utilising antibody-conjugated-CLA nanomicelle technology.Methodology/principal findingsWe invented and characterised an amphiphilic CLA-loaded whey protein co-polymer (CLA-W) as an IV injectable protein nanocarrier. Rabbit anti-Schistosoma mansoni infection (anti-SmI) and anti-Schistosoma mansoni alkaline phosphatase specific IgG antibodies were purified from rabbit sera and conjugated to the surface of CLA-W co-polymer to form antibody-conjugated-CLA-W nanomicelles (Ab-CLA-W). We investigated the schistosomicidal effects of CLA-W and Ab-CLA-W in a mouse model of Schistosoma mansoni against early and late stages of infection. Results showed that conjugation of nanomicelles with antibodies, namely anti-SmI, significantly enhanced the micelles' schistosomicidal and anti-pathology activities at both the schistosomula and adult worm stages of the infection resulting in 64.6%-89.9% reductions in worm number; 72.5-94% and 66.4-85.2% reductions in hepatic eggs and granulomas, respectively. Treatment induced overall improvement in liver histopathology, reducing granuloma size and fibrosis and significantly affecting egg viability. Indirect immunofluorescence confirmed CLA-W-mediated antigen exposure on the worm surface. Electron microscopy revealed extensive ultrastructural damage in worm tegument induced by anti-SmI-CLA-W.Conclusion/significanceThe novel antibody-targeted nano-sized CLA delivery system offers great promise for treatment of Schistosoma mansoni infection and control of its transmission. Our in vivo observations confirm an immune-mediated enhanced effect of the schistosomicidal action of CLA and hints at the prospect of nanotechnology-based immunotherapy, not only for schistosomiasis, but also for other parasitic infections in which chemotherapy has been shown to be immune-dependent. The results propose that the immunodominant reactivity of the anti-SmI serum, Schistosoma mansoni fructose biphosphate aldolase, SmFBPA, merits serious attention as a therapeutic and vaccine candidate

Hypothetical diagram of lipid nanocapsules incorporating miltefosine.

<p>Hypothetical diagram of lipid nanocapsules incorporating miltefosine.</p

TEM images of miltefosine lipid nanocapsules (MFS-LNCs).

<p>.(a) Plain MFS-LNCs, (b) MFS-LNC-CTAB⁺, (c) MFS-LNC-OA and (d) MFS-LNC-OA-CTAB⁺ at X 7,500 magnification. The scale bar represents 100nm.</p

Miltefosine release profiles.

<p>Miltefosine release from selected lipid nanocapsule formulations in PBS pH 7.4 at 37°C over a 24 h-study period. Data represent mean ± SD (n = 3). The inset is an enlargement of the release profiles for the first 8h of the release study.</p