Analysis of the Gadolinium retention in the Experimental Autoimmune Encephalomyelitis (EAE) murine model of Multiple Sclerosis

ObjectivesThe aim of this study is to quantitatively investigate, at the preclinical level, the extent of Gd retention in the CNS, and peripheral organs, of immune-mediated murine models (Experimental Autoimmune Encephalomyelitis –EAE) of Multiple Sclerosis, compared to control animals, upon the injection of gadodiamide. The influence of the Gadolinium Based Contrast Agent administration timing during the course of EAE development is also monitored.MethodsEAE mice were injected with three doses (1.2 mmol/kg each) of gadodiamide at three different time points during the EAE development and sacrificed after 21 or 39 days. Organs were collected and the amount of Gd was quantified through Inductively Coupled Plasma-Mass Spectrometry. Transmission electron microscopy (TEM) and MRI techniques were applied to add spatial and qualitative information to the obtained results.ResultsIn the spinal cord of EAE group, 21 days after gadodiamide administration, a significantly higher accumulation of Gd occurred. Conversely, in the encephalon, a lower amount of Gd retention was reached, even if differences emerged between EAE and controls mice. After 39 days, the amounts of retained Gd markedly decreased. TEM validated the presence of Gd in CNS. MRI of the encephalon at 7.1T did not highlight any hyper intense region.ConclusionIn the spinal cord of EAE mice, which is the mostly damaged region in this specific animal model, a preferential but transient accumulation of Gd is observed. In the encephalon, the Gd retention could be mostly related to inflammation occurring upon immunization rather than to demyelination.     

Multiple Testing for Identifying Effective and Safe Treatments

In the literature various multiple test procedures to compare k treatments with a control have been investigated. They can be applied to establish either treatment efficacy or treatment safety. In this paper we propose procedures which control the multiple level α with respect to efficacy and safety simultaneously. On the one hand we consider a method with stagewise rejective adjustments of local levels applied to appropriately defined subfamilies of null hypotheses. When order restrictions are assumed to hold among the parameters of interest we can alternatively split the multiple level between the families of efficacy and safety null hypotheses. If either all treatments are declared to be safe or all are declared to be effective then the other family can be tested at the full multiple level α, respectively. The methods are compared in a simulation study.