Post Transplantation Cyclophosphamide Improves Outcome of Autologous Hematopoietic Stem Cell Transplantation in Animal Model of Multiple Sclerosis

Abstract

Experimental allergic encephalomyelitis (EAE) is the animal model of multiple sclerosis (MS). Autologous hematopoietic stem cell transplantation (AHSCT) has recently been recognized as the standard treatment for MS. The aim of our experiment was to investigate the effect of AHSCT with the addition of low-dose post-transplantation cyclophosphamide (Cy) on EAE in rats. Low dose post-transplantation Cy is used in haploidentical HSCT to reduce the risk of graft versus host disease. We hypothesized that it could bring additional benefit in autologous HSCT in autoimmune diseases. Rats with evoked EAE were treated with high dose (125 mg/kg) Cy, followed by AHSCT or high dose (125 mg/kg) Cy followed by AHSCT followed by low dose (20 mg/kg) Cy in two-time schedules—with the therapy applied during the pre-symptomatic or symptomatic phase of the disease. Both AHSCT and AHSCT with post-transplantation Cy in accordance with both time schedules reduce the intensity of the inflammatory response in the CNS, in comparison with non-treated EAE rats. The reduction of clinical symptoms was present in all AHSCT treatment protocols, however, it was significantly stronger when post-transplantation Cy was given during the symptomatic phase of the disease. AHSCT with the addition of post HSCT low dose Cy improved the results of AHSCT by not only reducing the intensity of inflammation in the CNS but also by significantly reducing the clinical symptoms in treated animals when compared to AHSCT alone. We provide an experimental rationale that the addition of post-transplantation Cy may improve the outcome of HSCT in MS. Graphic Abstract

Effect of Hematopoietic Stem Cell Transplantation and Post-Transplantation Cyclophosphamide on the Microglia Phenotype in Rats with Experimental Allergic Encephalomyelitis

“…This study is the continuation of research published by Kasarełło et al ( 2021 ). The experiments were conducted as described previously.…”

“…The presented experiments are the continuation of our previous studies conducted using the animals with EAE evoked, which results are described in the article of Kasarełło et al ( 2021 ). Current research aims to analyze the mechanism underlying the previously observed changes in the disease course in rats.…”

“…EAE was induced at day 0 (0 DPI – day post immunization) as described before (Kasarełło et al 2021 ). The onset of clinical symptoms in this EAE model was observed at 10–11 DPI.…”

“…Animals were injected with a high-dose of Cy (125 mg/kg, Baxter) 1 day before AHSCT, which was performed by injecting the cell suspension (20 × 10 6 cells in 0.5 ml PBS) into the tail vein of rats. The method of hematopoietic stem cell collection was described earlier (Kasarełło et al 2021 ). Three and 4 days after AHSCT part of the animals received an additional low-dose of Cy (20 mg/kg).…”

“…We showed that applied treatment was efficient in decreasing the clinical symptoms of EAE observed in rats, decreased the number of days with present clinical symptoms, and also reduced the inflammatory infiltrations in the spinal cord. Furthermore, we extended the study with novel variants of therapy involving the administration of an additional, low-dose of Cy after AHSCT what noticeably boosted the effectiveness of the therapy (Kasarełło et al 2021 ). The rationale for using the additional low-dose of Cy was to eliminate the autoreactive lymphocytes possibly present in the hematopoietic stem cell graft.…”