Bruno Stankoff thanks the CEA (Commissariat lnergie atomique) and the European Leukodystrophy Foundation for their support. processes into the area vacated by the ablated cell (arrowhead) and later starts to enwrap axons between 3 and 8 h. The larvae were anaesthesized during both ablation and time lapse and then placed on their side on glass-bottomed 35 mm Petri dishes. The time lapse images were captured using 40 oil-immersion objectives mounted on a motorized Zeiss Axiovert 200 microscope equipped with a Perkin Elmer ERS spinning disk confocal system with a heated stage and chamber to maintain embryos at 28.5oC (Kirby (Nunes by the polysialylated form of the neural adhesion molecule (PSA-NCAM) (Zhang Antibody kindly provided by Poul H. Jensen, Aarhus, Denmark. (DCF) Abundant immune cells are detected in the same remyelinating lesion and identified as foamy macrophages (KiM1P in D) as well as T cells stained for CD3 (E) and CD8 (F). Scale bar: 50 m. The causeCeffect relationship between myelin repair and macrophage activation/tissue invasion in MS was confirmed by experiments in rodent focal demyelination models showing that macrophage depletion impairs remyelination (Kotter and LIF promotes remyelination in EAE (Butzkueven = is the distance between two branch points (Lubetzki and Zalc, 2001). Our knowledge of internodal axonal signals is also Piroxicam (Feldene) derived from developmental myelination studies in rodents. The adhesion molecule L1 positively regulates CNS and PNS myelination whereas Piroxicam (Feldene) Neuregulin 1 (Nrg1) type III is a major regulator of PNS myelination (Barbin and accumulates in chronic lesions in MS and EAE (Back while measuring its effect on functional recovery. The most frequently used imaging technology in this regard is currently MRI. Conventional T1 hypointense lesions likely indicate irreversible demyelination and axonal loss while T2 hyperintense lesions may reflect inflammation or persisting damage (reviewed in Neema and (Fig. 3A; Stankoff on MS brains sections a clear fluorescent staining of the normal appearing white matter (NAWM) was obtained. The demyelinated area (Dem delineated by dotted line in the upper left corner) was visualized as a lack of staining. In the shadow plaque area (Rem surrounded by arrowheads), BMB staining is of intermediate intensity between that observed in demyelinated plaques (Dem) and normal appearing white matter (NAWM). (C) CNS PET imaging using [11C]-BMB (about 100 MBq) injected intravenously in an anaesthetized baboon. This 110 min PET examination was performed using an ECAT HR+ camera. The axial slice from PET imaging was co-registered with a corresponding slice of the brain MRI scan. (A) and (B) are Figs 4A and 5F reproduced with Copyright (2006) National Academy of Sciences, USA (Stankoff testing of putative remyelination enhancers will be slow and uncertain. Concomitantly, the postulated impact of remyelination on the clinical course of MS should become measurable with increasingly myelin-specific imaging technologies. We may be able to learn from research into spinal cord injury, where there is great interplay between damaged axons and myelin-forming cells and where stimulation of remyelination plays an important role in functional recovery (Pearse em et al /em ., 2007). Promoters of neurite outgrowth may also be important in MS as transected and damaged axons cannot be effectively remyelinated. The characterization of the NOGO receptor complex, its interaction with myelin inhibitors (reviewed by Schwab em et al /em ., 2006) and the demonstration that intracellular cAMP and its downstream targets may promote axonal regeneration (reviewed by Hannila and Filbin, 2008), have led to new SCK clinical approaches in attempting to treat spinal cord injury (Rossignol em et al /em ., 2007). If patients with spinal cord injury show motor improvement in clinical trials, it might also be of benefit in some MS patients with acute axonal damage. Bearing in Piroxicam (Feldene) mind that remyelination.