In the last six months, the EFNS Scientific Fellowship programme gave me the opportunity to work as visiting scientist in the Laboratory for Molecular Neurology, coordinated by Prof. Dr. Orhan Aktas, at the Department of Neurology of the Heinrich-Heine University, Düsseldorf, Germany, chaired by Prof. Dr. Hans-Peter Hartung.
Since my arrival in Düsseldorf, I was encouraged by Prof. Aktas to integrate into the Laboratory as well as the ongoing work planning of his research group. I immediately had the feeling that my new colleagues were used to work in a very cooperative setting, wishing to create a welcoming environment and sharing their expertise during the daily work and the weekly scientific lab meetings. During my stay in Düsseldorf, I had not only the opportunity to improve my knowledge in the establishment of the murine model of neuroinflammation (experimental autoimmune encephalomyelitis – EAE), which represented one of the goals of my fellowship, but also to bring my contribution in terms of neuroimmunology/neuropathology background and clinical experience on multiple sclerosis.
The aim of our project was to test the efficacy of the calcium homeostasis regulation as strategy to prevent neurodegeneration during neuroinflammation. For this purpose, we tested the efficacy of nimodipine, a dihydropiridine calcium channel blocker selectively binding to L-type voltage-gated calcium channels (VGCCs), on EAE, the animal model for multiple sclerosis (MS).
Demyelination and relative axonal preservation has been considered for a long time the distinguish feature of MS. However, in the last years, axonal and neuronal pathology has been reported as an early feature of MS, mainly influencing the long-term clinical outcome.
Nimodipine is the currently used drug in clinical practice in the prevention of cerebral vasospasm following subarachnoid hemorrhage with a safe benefit/risk profile. We studied the effect of nimodipine on disease onset and progression in two different murine models of active EAE, the relapsing-remitting (RR) model in SJL/J mice and the chronic model in C57BL/6 mice.
In mice with RR EAE the clinical peak of the disease was followed by remission whithout any difference between the preventive nimodipine-treated group and the vehicle group. However, nimodipine determined a more evident clinical remission after the first relapse, while in the vehicle-treated group the remission phase was followed by a chronic progressive course. Otherwise, in the nimodipine-treated group the disease continued to show a RR course until day 54 post-immunization and a lower mean clinical score.
In the chronic C57Bl/6 EAE, the preventive treatment with nimodipine was associated with a slightly delayed disease onset and a reduced mean clinical score.
The neuroprotective effect of nimodipine on tissue pathology was studied by immunohistochemistry and fluorescence microscopy on brain and spinal cord sections. The extent of demyelination was assessed by Luxol Fast Blue and myelin basic protein (MBP) staining; axonal damage was assessed by neurofilament-M (NF-M) and amyloid precursor protein (APP) stainings.
Both brains and spinal cords from nimodipine-treated mice showed a significantly lower number of inflammatory infiltrates per section compared to that from the untreated mice. Nimodipine treatment determined significantly reduced demyelination and axonal damage in the inflammatory infiltrates from brains and spinal cords. The axonal damage was also found to be reduced in spinal cord inflammatory infiltrates from nimodipine-treated mice compared to that of vehicle-treated mice.
To confirm that the effect of nimodipine on EAE was purely neuroprotective without influence on the immune system, we studied the proliferation activity and activation of T cells from splenocyte and lymph node cultures by T[H]3 and flow cytometry. No differences in proliferation activity as well as viability between T-cells from nimodipine- and vehicle-treated mice were observed. As expected, no differences in terms of T cell activation were observed between cultures from nimodipine- and vehicle-treated mice through the study of the following activation markers by flow cytometry: CD25, CD44, CD54, CD62L, CD69, and CD127.
All these data confirm that nimodipine could be a possible neuroprotective agent to be added to currently available therapies for MS. It represents indeed a good model to study calcium homeostasis in neuroinflammation and warrants further studies.
In conclusion, this fellowship gave me a further valuable insight into basic research in neurodegeneration of neuroinflammatory diseases and the animal model of multiple sclerosis, and made possible to achieve the major goals of the project.
I would also like to highlight that Düsseldorf, the state capital of Northrhine-Westphalia, is a pleasant place to live in, and it was recently confirmed as the city with the best quality of life in Germany.
I would like to thank Prof. Dr. Hans-Peter Hartung for welcoming me in his Department and Prof. Dr. Orhan Aktas for accepting me in his research group and for supporting as well as supervising the experimental work of the project. I would like to thank my colleagues in Düsseldorf for their efforts to make the work in the laboratory productive and pleasant. I feel that this experience will be an important step in my career and I would strongly recommend it to young neurologists involved in basic/translational and clinical research aiming at academic positions. The Department of Neurology at the Heinrich-Heine University in Düsseldorf and the laboratory coordinated by Prof. Dr. Aktas are the right place to apply for everyone interested in neuroinflammatory diseases.
Finally, I would like to thank the EFNS for the support: without the Fellowship programme this experience would probably have not been possible.
Dr. Lorenzo de Santi is working at the University of Siena, Department of Neurological Sciences in Siena, Italy