The outcome of mesenchymal stem cells therapy for experimental toxoplasmosis

Background: Toxoplasmosis is considered one of the widest spread parasitic infections that affects approximately one third of human population. The formation of resident tissue cysts in chronically infected hosts is a challenge as none of the available drugs is capable of eradicating encysted forms of the parasite. Reactivation of dormant infection could be disastrous in immunosuppression states. The application of stem cells (SCs) as promising therapy was tried in some parasitic diseases. Objective: In this work, SCs therapy was investigated as a therapeutic line in treatment of murine toxoplasmosis. Material and Methods: Avirulent strain of T. gondii (ME49) was used to induce chronic infection in five groups of experimental albino mice {negative non-infected, non-treated control; positive infected, non-treated control; infected, spiramycin + pyrimethamine + folinic acid (SPF)-treated; infected SCs-treated; infected combined therapy (SPF+SCs)-treated}. Parasitological assessment was by determination of number and size of Toxoplasma cysts in different mice tissues. Descriptive histopathological study of different tissues of mice using hematoxylin and eosin (H&E) stain, and immunohistochemical (HIC) studies for assessment of CD8(+) in different tissues as a result of toxoplasmosis and the tested therapeutics were performed to investigate the curable role of bone marrow mesenchymal stem cells (BM MSCs). Results: The outcome revealed significant decrease in number and size of brain tissue cysts on combining SCs with SPF. The group tested by SCs as mono-therapy showed poor curable role, as revealed by results of liver, spleen, eye and brain tissues studies. Same results were confirmed by the recruitment of CD8(+) noted by the immunohistochemical study of brain and spleen sections. Conclusion: BM MSCs alone have a poor therapeutic role than when combined with SPF for treatment of toxoplasmosis.