Investigating the antifibrotic effect of the antiparasitic drug Praziquantel in in vitro and in vivo preclinical models

Abstract

Tissue fibrosis underlies the majority of human mortality to date with close to half of all reported deaths having a fibrotic etiology. The progression of fibrosis is very complex and reputed irreversible once established. Although some preventive options are being reported, therapeutic options are still scarce and in very high demand, given the rise of diseases linked to fibroproliferative disorders. Our work explored four platforms, complementarily, in order to screen preventive and therapeutic potentials of the antiparasitic drug Praziquantel as a possible antifibrotic. We applied the mouse CCl 4driven liver fibrosis model, the mouse chronic schistosomiasis liver fibrosis model, as well as novel 2D and 3D human cell-based co-culture of human hepatocytes, KCs (Kupffer cells), LECs (Liver Endothelial Cells), HSCs (Hepatic Stellate Cells) and/or myofibroblasts to mimic in vivo fibrotic responses and dynamics. Praziquantel showed some effect on fibrosis marker when preventively administered before severe establishment of fibrosis. However, it failed to potently reverse already established fibrosis. Together, we provided a novel sophisticated multi-assay screening platform to test preventive and therapeutic antifibrotic candidates. We further demonstrated a direct preventive potential of Praziquantel against the onset of fibrosis and the confirmation of its lack of therapeutic potential in reversing already established fibrosis. Discovered close to 50 years ago, Praziquantel (PZQ), a tetracyclic tetrahydroisoquinoline derivative administered as a racemate is the main drug therapy for combating flatworm parasites including tapeworms and schistosomes 1,2. In vitro and in vivo, the antischistosomal activity of PZQ enantiomers resides primarily in the (R)-enantiomer 3,4. The drug induces rapid paralysis of adult flatworm musculature and tegumental damage that facilitate the immunological removal of the worm from the host 5,6. As a result, the morbid manifestations of tissue-dwelling flatworm larvae were reported to be considerably, and even at times fully, controlled by PZQ treatment 7-25. One crippling and life-threatening sequelae resulting from Schistosoma eggs trapped in tissue is fibrosis 26,27. Fibrosis manifests as the uncontrolled formation of extracellular matrix in injured organ that progressively replaces the tissue parenchyma and drives pathology. Reduction of tissue fibrosis following PZQ treatment of flatworm-driven infections and injuries has been reported to be a direct consequence of the antiparasitic effect of the drug 28. The still poorly defined mode of action of the drug 5,6,29-32 has made definitive claims on its scope of action difficult. In fact, a recent report claiming PZQ-associated reduction of pathological

Ameliorative effects of Schisandrin B on Schistosoma mansoni-induced hepatic fibrosis in vivo

“…PZQ treatment decreases the number of hepatic eggs and therefore leads to a decrease in granuloma and fibrotic tissue formation. However, PZQ has only a little or no effect on the already established fibrotic tissues and is therefore not beneficial for patients in the later stage of schistosomiasis [ 84 , 86 ]. Sch B, in addition to the anti-parasitic effects shown in this study, can also reverse the existing fibrosis [ 25 , 56 ].…”

“…Although some study suggested that the persistent use of PZQ may also provide an antifibrotic effect against schistosomiasis [82][83][84], this beneficial effect usually occurs at an earlier stage [84][85][86]. PZQ treatment decreases the number of hepatic eggs and therefore leads to a decrease in granuloma and fibrotic tissue formation.…”

Praziquantel Treatment of Schistosoma mansoni Infected Mice Renders Them Less Susceptible to Reinfection

“…The volume of administration to mice was 200 µL. S. mansoni-infected mice were administered by oral gavage twice during week 6 post infection for deparasitization, as previously optimized in mice (14). Deparasitized animals were further subjected or not to cycles of reinfection and deparasitization with PZQ up to a maximum total of 3 infection cycles for some animals.…”

“…The upper aqueous serum phase was aliquoted into tubes and stored at -80°C until further use. Livers were excised then approximately one-quarter of each liver was used for cell isolation and flow cytometric analyses as previously described (14,15), another quarter was stored in formalin for histology, a quarter used for egg count and the last quarter used to estimate the relative tissue cytokine contents as a proxy for the local response elicited by trapped parasite eggs.…”

COMPLEXATION OF PRAZIQUANTEL WITH α-, β- AND y-CYCLODEXTRINS IN AQUEOUS-ALCOHOLIC SOLUTIONS

“…It is a broadspectrum drug used to treat many parasitic infections, including cysticercosis, tapeworm disease, and clonorchiasis (Zhang et al, 2020). Praziquantel is considered a relatively low-toxic drug that does not possess embryotoxic, mutagenic, and teratogenic properties and does not affect the postnatal development of the body (Demidov, 1982;Engasheva, 2011;Garcia et al, 2011;Zolotareva and Zeynalov, 2015;Harvie et al, 2019;Liu et al, 2019;Nono et al, 2020). At the same time, with all the listed advantages, praziquantel has several disadvantages: 1) low solubility in water and, as a result, limited bioavailability of this substance in liquid compositions; 2) lack of the necessary activity concerning the roundworms; 3) the lack of complete clearance of praziquantel from the body, which, with prolonged use, can lead to increased toxicity to animals; 4) pronounced bitter taste, which is a significant obstacle in the development of medicinal products for oral administration and, in particular, their liquid forms intended for dogs and cats (Subbotin et al, 2000;Xu et al, 2009;Sousa-Figueiredo et al, 2012;Zolotareva and Zeynalov, 2015).…”