Pathological and immunological evaluation of different regimens of praziquantel treatment in a mouse model of Schistosoma mansoni infection

The synergistic effect of Ficus carica nanoparticles and Praziquantel on mice infected by Schistosoma mansoni cercariae

Bilharzia is a parasitic flatworm that causes schistosomiasis, a neglected tropical illness worldwide. Praziquantel (PZQ) is a commercial single treatment of schistosomiasis so alternative drugs are needed to get rid of its side effects on the liver. The current study aimed to estimate the effective role of Ficus carica nanoparticles (Fc-NPCs), silver nanoparticles (Ag-NPCs) and Ficus carica nanoparticles loaded on silver nanoparticles (Fc-Ag NPCs) on C57BL/6 black female mice infected by Schistosoma mansoni and treated with PZQ treatment. It was proved that schistosomiasis causes liver damage in addition to the PZQ is ineffective as an anti-schistosomiasis; it is recorded in the infected mice group and PZQ treated group as in liver function tests, oxidative stress markers & anti-oxidants, pro-inflammatory markers, pro-apoptotic and anti-apoptotic markers also in liver cells' DNA damage. The amelioration in all tested parameters has been clarified in nanoparticle-protected mice groups. The Fc-Ag NPCs + PZQ group recorded the best preemptive effects as anti-schistosomiasis. Fc-NPCs, Ag-NPCs and Fc-Ag NPCs could antagonize PZQ effects that were observed in amelioration of all tested parameters. The study showed the phytochemicals' nanoparticles groups have an ameliorated effect on the health of infected mice.

Contribution of parasite and host genotype to immunopathology of schistosome infections

BACKGROUND

The role of pathogen genotype in determining disease severity and immunopathology has been studied intensively in microbial pathogens including bacteria, fungi, protozoa and viruses but is poorly understood in parasitic helminths. The medically important blood fluke Schistosoma mansoni is an excellent model system to study the impact of helminth genetic variation on immunopathology. Our laboratory has demonstrated that laboratory schistosome populations differ in sporocyst growth and cercarial production in the intermediate snail host and worm establishment and fecundity in the vertebrate host. Here, we (i) investigate the hypothesis that schistosome genotype plays a significant role in immunopathology and related parasite life history traits in the vertebrate mouse host and (ii) quantify the relative impact of parasite and host genetics on infection outcomes.

METHODS

We infected BALB/c and C57BL/6 mice with four different laboratory schistosome populations from Africa and the Americas. We quantified disease progression in the vertebrate host by measuring body weight and complete blood count (CBC) with differential over a 12-week infection period. On sacrifice, we assessed parasitological (egg and worm counts, fecundity), immunopathological (organ measurements and histopathology) and immunological (CBC with differential and cytokine profiles) characteristics to determine the impact of parasite and host genetics.

RESULTS

We found significant variation between parasite populations in worm numbers, fecundity, liver and intestine egg counts, liver and spleen weight, and fibrotic area but not in granuloma size. Variation in organ weight was explained by egg burden and intrinsic parasite factors independent of egg burden. We found significant variation between infected mouse lines in cytokine levels (IFN-γ, TNF-α), eosinophils, lymphocytes and monocyte counts.

CONCLUSIONS

This study showed that both parasite and host genotype impact the outcome of infection. While host genotype explains most of the variation in immunological traits, parasite genotype explains most of the variation in parasitological traits, and both host and parasite genotypes impact immunopathology outcomes.

Matrix metalloproteinases inhibition reveals the association between inflammation, collagen accumulation and intestinal translocation of Schistosoma mansoni eggs in vivo

Schistosomiasis mansoni is a parasitic infection that causes enterohepatic morbidity associated with severe granulomatous inflammation triggered by parasite eggs. In this disease, granulomatous inflammation leads to intestinal erosion and environmental excretion of S. mansoni eggs from feces, an essential process for propagating the parasite and infecting host organisms. Metalloproteinases (MMP) are involved in S. mansoni-induced hepatic granulomatous inflammation and fibrosis. However, the relationship between MMP and collagen accumulation with the intestinal excretion of parasite eggs remains unclear. Thus, the present study investigated whether MMP inhibition is capable of modulating granulomatous inflammation, collagen accumulation and mechanical resistance to the point of influencing the dynamics between intestinal retention and excretion of S. mansoni eggs in infected mice. Our findings indicated that doxycycline (a potent MMP inhibitor) aggravates intestinal inflammation and subverts collagen dynamics in schistosomiasis. By attenuating MMP-2 and MMP-9 activity, this drug is capable of enhancing fibrosis and mechanical resistance of the intestinal wall, hindering S. mansoni eggs translocation. Although collagen content was not correlated with MMP activity, intestinal retention and fecal excretion of parasite eggs in untreated mice; these correlations were observed for doxycycline-treated animals. Thus, our study provides evidence that doxycycline is able to attenuate fecal elimination of S. mansoni eggs by inhibiting MMP-2 and MMP-9 activity, events potentially associated with excessive collagen accumulation, which increases intestinal mechanical resistance and hinders eggs translocation through the intestinal wall. Variations in intestinal collagen dynamics are relevant since they may represent changes in the environmental dispersion of S. mansoni eggs, bringing repercussions for schistosomiasis propagation.

Contribution of parasite and host genotype to immunopathology of schistosome infections

Background

The role of pathogen genotype in determining disease severity and immunopathology has been studied intensively in microbial pathogens including bacteria, fungi, protozoa, and viruses, but is poorly understood in parasitic helminths. The medically important blood fluke Schistosoma mansoni is an excellent model system to study the impact of helminth genetic variation on immunopathology. Our laboratory has demonstrated that laboratory schistosome populations differ in sporocyst growth and cercarial production in the intermediate snail host and worm establishment and fecundity in the vertebrate host. Here, we (i) investigate the hypothesis that schistosome genotype plays a significant role in immunopathology and related parasite life history traits in the vertebrate mouse host and (ii) quantify the relative impact of parasite and host genetics on infection outcomes.

Methods

We infected BALB/c and C57BL/6 mice with four different laboratory schistosome populations from Africa and the Americas. We quantified disease progression in the vertebrate host by measuring body weight and complete blood count (CBC) with differential over an infection period of 12 weeks. On sacrifice, we assessed parasitological (egg and worm counts, fecundity), immunopathological (organ measurements and histopathology), and immunological (CBC with differential and cytokine profiles) characteristics to determine the impact of parasite and host genetics.

Results

We found significant variation between parasite populations in worm numbers, fecundity, liver and intestine egg counts, liver and spleen weight, and fibrotic area, but not in granuloma size. Variation in organ weight was explained by egg burden and by intrinsic parasite factors independent of egg burden. We found significant variation between infected mouse lines in cytokines (IFN-γ, TNF-α), eosinophil, lymphocyte, and monocyte counts.

Conclusions

This study showed that both parasite and host genotype impact the outcome of infection. While host genotype explains most of the variation in immunological traits, parasite genotype explains most of the variation in parasitological traits, and both host and parasite genotype impact immunopathology outcomes.

Effects of the probiotic Bacillus cereus GM on experimental schistosomiasis mansoni

Probiotics contribute to the integrity of the intestinal mucosa and preventing dysbiosis caused by opportunistic pathogens, such as intestinal helminths. Bacillus cereus GM obtained from Biovicerin® was cultured to obtain spores for in vivo evaluation on experimental schistosomiasis. The assay was performed for 90 days, where all animals were infected with 50 cercariae of Schistosoma mansoni on the 15th day. Three experimental groups were formed, as follows: G1-saline solution from the 1st until the 90th day; G2-B. cereus GM (105 spores in 300 μL of sterile saline) from the 1st until the 90th day; and G3-B. cereus GM 35th day (onset of oviposition) until the 90th day. G2 showed a significant reduction of 43.4% of total worms, 48.8% of female worms and 42.5% of eggs in the liver tissue. In G3, the reduction was 25.2%, 29.1%, and 44% of the total number of worms, female worms, and eggs in the liver tissue, respectively. G2 and G3 showed a 25% (p < 0.001) and 22% (p < 0.001) reduction in AST levels, respectively, but ALT levels did not change. ALP levels were reduced by 23% (p < 0.001) in the G2 group, but not in the G3. The average volume of granulomas reduced (p < 0.0001) 65.2% and 46.3% in the liver tissue and 83.0% and 53.2% in the intestine, respectively, in groups G2 and G3. Th1 profile cytokine (IFN-γ, TNF-α, and IL-6) and IL-17 were significantly increased (p < 0.001) stimulated with B. cereus GM in groups G2 and G3. IL-4 showed significant values when the stimulus was mediated by ConA. By modulating the immune response, B. cereus GM reduced the burden of worms, improved some markers of liver function, and reduced the granulomatous inflammatory reaction in mice infected with S. mansoni, especially when administered before infection.

Rutin, a Flavonoid Compound Derived from Garlic, as a Potential Immunomodulatory and Anti-Inflammatory Agent against Murine Schistosomiasis mansoni

Schistosomiasis is a tropical disease caused by trematode worms. The inflammatory response of the host to schistosome eggs leads to formation of granuloma in the liver and intestine. Praziquantel (PZQ) is still an effective treatment for schistosomiasis, however resistance development may reduce its efficacy. The current study investigated the possible immunomodulatory and anti-inflammatory action of rutin, a natural flavonoid compound isolated from garlic, on liver fibrotic markers in mice infected with S. mansoni in comparison to PZQ. Male albino CD1 mice were infected with 100 ± 2 S. mansoni cercariae/mouse and treated with garlic, rutin, or PZQ. At the end of the experiment, the liver and intestines were harvested for parasitological and histological assessment and to analyze the proinflammatory cytokine. Rutin significantly affects the pathological alterations caused by Schistosoma in the liver. This may be partially explained by a decrease in the number of eggs trapped in the tissues of the liver and a modification in the serum levels of certain cytokines, which are implicated in the formation of Schistosoma granuloma. In conclusion, rutin has strong anti-schistosome properties in vivo, raising the possibility that rutin might be further investigated as a therapy for S. mansoni.