Schistosoma mansoni sarco/endoplasmic reticulum Ca2+ ATPases (SERCA): role in reduced sensitivity to praziquantel

Therapeutic efficacy of candidate antischistosomal drugs in a murine model of schistosomiasis mansoni

Schistosomiasis is a neglected tropical disease associated with considerable morbidity. Praziquantel (PZQ) is effective against adult schistosomes, yet, it has little effect on juvenile stages, and PZQ resistance is emerging. Adopting the drug repurposing strategy as well as assuming enhancing the efficacy and lessening the doses and side effects, the present study aimed to investigate the in vivo therapeutic efficacy of the widely used antiarrhythmic, amiodarone, and diuretic, spironolactone, and combinations of them compared to PZQ. Mice were infected by Schistosoma mansoni "S. mansoni" cercariae (Egyptian strain), then they were divided into two major groups: Early- [3 weeks post-infection (wpi)] and late- [6 wpi] treated. Each group was subdivided into seven subgroups: positive control, PZQ, amiodarone, spironolactone, PZQ combined with amiodarone, PZQ combined with spironolactone, and amiodarone combined with spironolactone-treated groups. Among the early-treated groups, spironolactone had the best therapeutic impact indicated by a 69.4% reduction of total worm burden (TWB), 38.6% and 48.4% reduction of liver and intestine egg load, and a significant reduction of liver granuloma number by 49%. Whereas, among the late-treated groups, amiodarone combined with PZQ was superior to PZQ alone evidenced by 96.1% reduction of TWB with the total disappearance of female and copula in the liver and intestine, 53.1% and 84.9% reduction of liver and intestine egg load, and a significant reduction of liver granuloma number by 67.6%. Comparatively, spironolactone was superior to PZQ and amiodarone in the early treatment phase targeting immature stages, while amiodarone had a more potent effect when combined with PZQ in the late treatment phase targeting mature schistosomes.

Microwave-assisted hydrothermal fabrication of hierarchical-stacked mesoporous decavanadate-intercalated ZnAl nanolayered double hydroxide to exterminate different developmental stages of Trichinella spiralis and Schistosoma mansoniin-vitro

Hierarchically stacked mesoporous zinc-aluminium nanolayered-double-hydroxide intercalated with decavanadate (ZnAl-LDH-V₁₀O₂₈) is constructed using anion-exchange process via microwave-hydrothermal treatment. Physicochemical properties of ZnAl-LDH-V₁₀O₂₈ are characterized in detail. Decavanadate anions are intimately interacted with ZnAl-LDH nanosheets, generating highly ordered architecture of well-dimensioned stacking blocks of brucite-like nanolayers (∼8 nm). Such hierarchy improves surface-porosity and electrical-impedivity of ZnAl-LDH-V₁₀O₂₈ with declining its zeta-potential (ζ_av = 8.8 mV). In-vitro treatment of various developmental-stages of Trichinella spiralis and Schistosoma mansoni by ZnAl-LDH-V₁₀O₂₈ is recognized using parasitological and morphological (SEM/TEM) analyses. ZnAl-LDH-V₁₀O₂₈ exterminates muscle-larvae and adult-worms of Trichinella spiralis, and juvenile and adult Schistosoma mansoni, yielding near 100% mortality with rates achieving 5%/h within about 17 h of incubation. This parasiticidal behavior results from the symphony of biological activity gathering decavanadate and LDH-nanosheets. Indeed, ZnAl-LDH-V₁₀O₂₈ nanohybrid sample, as a promissory biocide for killing food-borne/waterborne parasites, becomes a futuristic research hotspot for studying its in-vivo bioactivity and impact-effectiveness on parasite molecular biology.

Human umbilical cord blood mesenchymal stem cells as a potential therapy for schistosomal hepatic fibrosis: an experimental study

The objective of our study was to assess the effect of human umbilical cord blood (HUCB) mesenchymal stem cells (MSCs) transplantation on schistosomal hepatic fibrosis in mice. The study animals were divided into three groups. Group I is a control group, where the mice were infected with Schistosoma mansoni cercariae and remained untreated. The mice of the other two groups were infected and treated with either praziquantel (Group II) or HUCB-MSCs (Group III). Liver function tests, as well as histopathological evaluation of liver fibrosis using hematoxylin and eosin and Masson's trichrome stains, were performed. Additionally, an immunohistochemical study was carried out using anti-glial fibrillary acidic protein (GFAP) in hepatic stellate cells. Compared to the control group, the treated (praziquantel and MSCs) groups showed a substantial improvement, with a significant difference regarding the histopathological evaluation of liver fibrosis in the MSCs-treated group. In conclusion, MSCs could be a promising and efficient cell therapy for liver fibrosis.

Involvement of calcium homeostasis and unfolded protein response in autophagy co-induced by molybdenum and cadmium in duck (Anas platyrhyncha) brain

Excess molybdenum (Mo) and cadmium (Cd) are harmful to animals, but neurotoxicity caused by Mo and Cd co-exposure in ducks is yet unknown. To assess joint impacts of Mo and Cd on autophagy via calcium homeostasis and unfolded protein response (UPR) in duck brain, 40 healthy 7-day-old ducks (Anas platyrhyncha) were assigned to 4 groups at random and fed diets supplemented with different doses of Mo or/and Cd for 16 weeks, respectively. Brain tissues were excised for experiment. Results exhibited that Mo or/and Cd disturbed calcium homeostasis by decreased ATPase activities and increased calcium (Ca) content, and upregulated calcium homeostasis-related factors Ca²⁺/CAM-dependent kinase IIɑ (CaMKIIɑ), calcineurin (CaN), inositol-1,4,5-trisphosphate receptor (IP₃R), and calreticulin (CRT) expression levels. Meanwhile, the upregulation of UPR-related factor expression levels indicated that Mo or/and Cd activated UPR. Moreover, Mo or/and Cd triggered autophagy through promoting the number of autophagosomes and LC3II immunofluorescence intensity and altering autophagy key factor expression levels. Correlation analysis showed that there were obvious connections among Ca²⁺ homeostasis, endoplasmic reticulum (ER) stress, and autophagy induced by Mo or/and Cd. Thence, it can be speculated that autophagy initiated by Mo or/and Cd may be associated with interfering Ca²⁺ homeostasis and triggering UPR.

Praziquantel-encapsulated niosomes against Schistosoma mansoni with reduced sensitivity to 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.

Objective:

To overcome the tolerance to PZQ using nanotechnology after laboratory induction of a Schistosoma 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. We obtained a remarkable increase in the percentage reduction of tissue egg counts in the liver and intestine (97.68% and 98.56%, respectively) associated with a massive increase in dead eggs and the 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.

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

Due to the high prevalence of schistosomiasis and the wide use of praziquantel solely for mass drug administration to control the disease, there is a great concern about the potential emergence of reduced susceptibility strains. This, together with the concern that praziquantel is ineffective against juvenile worms highlight the importance of developing an alternative anti-schistosomal drug. Using nonsteroidal anti-inflammatory drugs against schistosome infection is considerable. The present study evaluated the effect of oral administration of five days celecoxib regimen (20 mg/kg/day) against different developmental stages of Schistosoma mansoni infection. This regimen induced significant reduction in worm burden, tissue egg count, individual female fecundity and the mean percentage of immature and mature eggs with increased mean percentage of dead eggs. More importantly, celecoxib was more potent than praziquantel in all these parasitological parameters (except in the worm burden when given against the adult stage where the difference was statistically non-significant). Scanning and transmission electron microscopy of the adult worms revealed severe tegumental damage, laceration of the muscular layers and oedema of the syncytial layer. There was disruption of the testicular, ovarian and vitelline glandular tissues with signs of apoptosis and abnormalities of the spermatozoa and the oocytes. Additionally, celecoxib induced reduction in the number and the size of the hepatic granulomata and also amelioration of the hepatic tissue pathology.