Effect of celecoxib against different developmental stages of experimental Schistosoma mansoni infection

Anti-toxoplasmic effects of celecoxib alone and combined with spiramycin in experimental mice

Even though toxoplasmosis is a worldwide parasitic disease caused by Toxoplasma gondii (T. gondii), the available drugs used for the treatment of symptomatic toxoplasmosis have multiple drawbacks. So, there is a considerable need to discover new potential therapeutic agents. The current study aimed to assess the effect of celecoxib (CELE) alone or combined with spiramycin against chronic toxoplasmosis in experimentally infected mice. The study documented the reduction rate of T. gondii cysts in brain tissues and ultrastructural changes through transmission electron microscopy after treatment. We also investigated pathological changes in the brain, liver, lung, and spleen, as well as the expression of TGF-β, iNOS, and pSTAT-1 in brain tissues. Other markers for kidney function and serum levels of interleukins 10 and 12 were also assessed. The study reported a reduction rate of T. gondii brain cyst count of 32.9 % after CELE treatment, 71.7 % after spiramycin treatment, and 75.7 % after combined treatment. Furthermore, the CELE and spiramycin combination improved the ultrastructure and histopathology in brain tissues while decreasing TGF-β, iNOS, and pSTAT-1 expression. The combined therapy ameliorated the inflammation of the liver, lung, and spleen, upregulated the IL-12 level, reduced the IL-10 level, and was accompanied by a reduction in creatinine and urea in serum. In conclusion, CELE increased spiramycin therapeutic efficacy, and their combination showed a better response than spiramycin alone. Thus, the CELE combination with spiramycin represents a hopeful therapy against chronic toxoplasmosis.

Current drug strategies for the treatment and control of schistosomiasis

INTRODUCTION

Schistosomiasis, one of the current Neglected Tropical Diseases (NTDs) affects over 230 million people globally, with nearly 700 million at risk in more than 74 countries. Praziquantel (PZQ) has served as the primary treatment for the past four decades; however, its effectiveness is limited as it solely eliminates adult worms. In regions where infections are frequent, PZQ exhibits only temporary efficacy and has restricted potential to disrupt the prolonged transmission of the disease.

AREAS COVERED

A comprehensive exploration using the PubMed database was conducted to review current pharmacotherapy approaches for schistosomiasis. This review also encompasses recent research findings related to potential novel therapeutics and the repurposing of existing drugs.

EXPERT OPINION

Current schistosoma treatment strategies, primarily relying on PZQ, face challenges like temporary effectiveness and limited impact on disease transmission. Drug repurposing, due to economic constraints, is decisive for NTDs. Despite PZQ's efficacy, its failure to prevent reinfection highlights the need for complementary strategies, especially in regions with persistent environmental foci. Integrating therapies against diverse schistosome stages boosts efficacy and impedes resistance. Uncovering novel agents is essential to address resistance concerns in tackling this neglected tropical disease. Integrated strategies present a comprehensive approach to navigate the complex challenges.

Immuno-molecular profile for Biomphalaria glabrata/Schistosoma mansoni interaction

The complex innate immune defense of Biomphalaria glabrata, the intermediate host of Schistosoma mansoni, governs the successful development of the intramolluscan stages of the parasite. The interaction between the snail and the parasite involves a complex immune molecular crosstalk between several parasite antigens and the snail immune recognition receptors, evoking different signals and effector molecules. This work seeks to discuss the immune-related molecules that influence compatibility in Biomphalaria glabrata/Schistosoma mansoni interaction and the differential expression of these molecules between resistant and susceptible snails. It also includes the current understanding of the immune molecular determinants that govern the compatibility in sympatric and allopatric interactions, and the expression of these molecules after immune priming and the secondary immune response. Herein, the differences in the immune-related molecules in the interaction of other Biomphalaria species with Schistosoma mansoni compared to the Biomphalaria glabrata model snail are highlighted. Understanding the diverse immune molecular determinants in the snail/schistosome interaction can lead to alternative control strategies for schistosomiasis.

Emerging roles for extracellular vesicles in Schistosoma infection

The co-evolution of Schistosoma and its host necessitates the use of extracellular vesicles (EVs) generated by different lifecycle stages to manipulate the host immune system to achieve a delicate balance between the survival of the parasite and the limited pathology of the host. EVs are phospholipid bilayer membrane-enclosed vesicles capable of transferring a complex mixture of proteins, lipids, and genetic materials to the host. They are nano-scale-sized vesicles involved in cellular communication. In this review, the author summarized the proteins involved in the biogenesis of schistosome-derived EVs and their cargo load. miRNAs are one cargo molecule that can underpin EVs functions and significantly affect parasite/host interactions and immune modulation. They skew macrophage polarization towards the M1 phenotype and downregulate Th2 immunity. Schistosoma can evade the host immune system's harmful effects by utilizing this strategy. In order to compromise the protective effect of Th2, EVs upregulate T regulatory cells and activate eosinophils, which contribute to granuloma formation. Schistosomal EVs also affect fibrosis by acting on non-immune cells such as hepatic stellate cells. These vesicles drew attention to translational applications in diagnosis, immunotherapy, and potential vaccines. A deep understanding of the interaction of schistosome-derived EVs with host cells will significantly increase our knowledge about the dynamics between the host and the worm that may aid in controlling this debilitating disease.

A single oral dose of celecoxib-loaded solid lipid nanoparticles for treatment of different developmental stages of experimental schistosomiasis mansoni

Schistosomiasis, a neglected tropical parasitic disease, is associated with severe pathology, mortality and economic loss. The treatment and control of schistosomiasis depends mainly on a single dose of praziquantel (PZQ). Drug repurposing and nanomedicine attract great attention to improve anti-schistosomal therapy. Previously, we reported that celecoxib (CELE), the non-steroidal anti-inflammatory drug, showed potent anti-schistosomal efficacy in an oral dose of 20 mg/kg/day for five days against different developmental stages of Schistosoma mansoni (S. mansoni) infection in mice. The aim of the current study was to shorten the duration of CELE treatment to reach an effective single oral dose against different developmental stages of S. mansoni infection using solid lipid nanoparticles (SLNs) as nano-carriers. The latter enhance the solubility, bioavailability and drug delivery and hence can decrease the frequency of administration which is of great clinical value. CELE-loaded SLNs showed good colloidal properties, high entrapment efficiency and drug loading, sustained biphasic release pattern with excellent storage stability. The used regimen was efficient against different developmental stages of S. mansoni infection with the most pronounced effect against the juvenile stage where the worm load, the hepatic egg count and the intestinal egg count were reduced by 86.39%, 91.45% and 90.11%, respectively. Meanwhile, when targeting the invasive and the adult stages, it induced reduction in the worm load by 73.55% and 78.22%, the hepatic egg count by 69.99% and 75.39% and the intestinal egg count by 77.57% and 79.89%, respectively. Additionally, CELE-loaded SLNs caused extensive tegumental damage of adult worms and marked improvement in the liver pathology.

Review: Schistosoma mansoni phosphatidylinositol 3 kinase (PI3K)/Akt/mechanistic target of rapamycin (mTOR) signaling pathway

Schistosoma mansoni worms are under a milieu of external and internal signaling pathways. The life-cycle stages are exposed to enormous stimuli within the mammalian and the snail hosts and as free-living stages in the fresh water. Furthermore, there is a unique interplay between the male and the female worms involving many stimuli from the male essential for full development of the female. PI3K/Akt/mTOR is an evolutionarily divergent signal transduction pathway universal to nearly every multicellular organism. This work reviews the Schistosoma mansoni PI3K/Akt/mTOR signal pathways and the involvement of the signal in the worms' physiology concerning the uptake of glucose, reproduction and survival. The inhibitors of the signal pathway used against Schistosoma mansoni were summarized. Given the importance of the PI3K/Akt/mTOR signal pathway, its inhibition could be a promising control strategy against schistosomiasis.