Regional variations in the extent and pattern of grey matter demyelination in multiple sclerosis: a comparison between the cerebral cortex, cerebellar cortex, deep grey matter nuclei and the spinal cord C P Gilmore, 1 I Donaldson, 1 L Bo ¨, 2,3 T Owens, 4 J Lowe, 5 N Evangelou 1 1 Department of Neurology, Queens Medical Centre NHS Trust, Nottingham, UK; 2 Department of Neuropathology, VU Medical Centre, Amsterdam, The Netherlands; 3 National Competence Centre for MS, Department of Neurology, Haukeland University Hospital, Bergen, Norway; 4 Department of Economics, University of Nottingham, UK; 5 Department of Neuropathology, University of Nottingham, UK Correspondence to: Dr C P Gilmore, Department of Neurology, B Floor Medical School, Queen’s Medical Centre NHS Trust, Nottingham NG7 2UH, UK; chris.gilmore@ nottingham.ac.uk Received 8 March 2008 Revised 7 May 2008 Accepted 12 May 2008 Published Online First 1 October 2008 ABSTRACT Background: Substantial grey matter (GM) demyelina- tion occurs in both the cerebral cortex and spinal cord in multiple sclerosis (MS). GM demyelination also occurs in the cerebellar cortex and the deep GM nuclei of the brain. However, no study has made a direct ‘‘within subject’’ comparison of the extent of GM pathology between these regions. Aim: To examine the extent and pattern of GM demyelination in the motor cortex, cingulate gyrus, cerebellum, thalamus and spinal cord in MS. Methods: Postmortem study using material from 14 MS cases and three controls. Sections were taken from the five predetermined areas and stained for proteolipid protein. The extent of GM and white matter (WM) demyelination was assessed in each region. Results and conclusion: Overall, 28.8% of the GM was demyelinated compared with 15.6% of the WM (p,0.001), with demyelination being greater in the GM than in the WM at each of the anatomical sites. There was substantial variation in the extent of demyelination between the different CNS regions. GM demyelination was most extensive in the spinal cord and cerebellum while WM demyelination was most prominent in the spinal cord. The factors influencing plaque topography in multiple sclerosis (MS) are not fully understood. The majority of white matter (WM) plaques occur in a perivenular distribution, with areas containing a high density of small veins and venules—such as the periventricular WM, leucocortical junction and the WM tracts of the brainstem and spinal cord— showing a preponderance for demyelination. 1 While it has been recognised that MS also involves grey matter (GM) structures, the conventional myelin stains used in these studies grossly under- estimate the true extent of this GM pathology. 2–4 In comparison, myelin protein immunohisto- chemistry is more sensitive for detecting GM demyelination, demonstrating extensive demyeli- nation in the cerebral cortex and spinal cord GM in MS. 4–6 However, it is unclear whether GM demye- lination is more prominent in the spinal cord, the cerebral cortex or other GM structures; compar- isons between studies are likely to be confounded by differences in MS subtype, disease duration, age, gender, etc. Therefore, in this study, we used autopsy material to quantify GM and WM demyelination in the cerebral cortex, cerebellum, spinal cord and thalamus, allowing us to make ‘‘within subject’’ comparisons of the extent of demyelination in these regions. MATERIALS AND METHODS Clinical material Formalin fixed, paraffin embedded autopsy material was obtained from 14 pathologically confirmed MS cases and three controls (MS Brain Bank, London, UK). Patients with MS (one man, 13 women) were aged 44–81 years (mean 56.6, median 56) with disease durations of 6–32 years (mean 23.7, median 22). Eleven cases had second- ary progressive MS (SPMS), two primary progres- sive MS (PPMS) and one relapsing remitting MS (RRMS). The controls (two women aged 69 and 78 years, one man aged 35 years) had no clinical or pathological evidence of neurological disease. The local research ethics committee approved the study. Preparation of the sections Sections (5 mm) were taken from seven predeter- mined areas of the CNS, irrespective of the macroscopic appearance: the motor cortex, cingu- late gyrus, cerebellum, thalamus and spinal cord (transverse sections from the cervical, thoracic and lumbar levels). Sections were stained for proteo- lipid protein (PLP) as described previously. 6 Measurement of GM and WM lesions The PLP stained sections were scanned in a slide scanner to produce a digital image. Using these images the GM/WM boundary and the MS lesions were manually outlined (AnalySIS Pro running SIS software; Olympus UK). The control cases were used to establish normal regional variations in myelin staining. Lesions were defined as sharply demarcated areas, characterised by either complete myelin loss or markedly reduced myelin density (likely to represent partially remyelinated lesions). The proportion of GM that was demyelinated (P GMd , ie, the area of demyelinated GM as a percentage of the total GM cross sectional area) and the proportion of WM that was demyelinated (P WMd ) was then calculated. Statistical analysis Paired t tests were used to compare P GMd with P WMd in each anatomical region (ie, each tissue section contained both GM and WM, hence paired tests). Correlations between P GMd and P WMd were Research paper 182 J Neurol Neurosurg Psychiatry 2009;80:182–187. doi:10.1136/jnnp.2008.148767 group.bmj.com on August 16, 2011 - Published by jnnp.bmj.com Downloaded from