Open AccessAbnormal Endothelial Tight Junctions in Active Lesions and Normal‐appearing White Matter in Multiple Sclerosis
Author(s) -
Plumb Jonnie,
McQuaid Stephen,
Mirakhur Meenakshi,
Kirk John
Publication year - 2002
Publication title -
brain pathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.986
H-Index - 132
eISSN - 1750-3639
pISSN - 1015-6305
DOI - 10.1111/j.1750-3639.2002.tb00430.x
Subject(s) - occludin , tight junction , pathology , white matter , multiple sclerosis , blood–brain barrier , medicine , magnetic resonance imaging , chemistry , anatomy , biology , central nervous system , neuroscience , microbiology and biotechnology , immunology , radiology
Blood‐brain barrier (BBB) breakdown, demonstrable in vivo by enhanced MRI is characteristic of new and expanding inflammatory lesions in relapsing‐remitting and chronic progressive multiple sclerosis (MS). Subtle leakage may also occur in primary progressive MS. However, the anatomical route(s) of BBB leakage have not been demonstrated. We investigated the possible involvement of interendothelial tight junctions (TJ) by examining the expression of TJ proteins (occludin and ZO‐1) in blood vessels in active MS lesions from 8 cases of MS and in normal‐appearing white (NAWM) matter from 6 cases. Blood vessels (10–50 per frozen section) were scanned using confocal laser scanning microscopy to acquire datasets for analysis. TJ abnormalities manifested as beading, interruption, absence or diffuse cytoplasmic localization of fluorescence, or separation of junctions (putative opening) were frequent (affecting 40% of vessels) in oil‐red‐O‐positive active plaques but less frequent in NAWM (15%), and in normal (<2%) and neurological controls (6%). Putatively “open” junctions were seen in vessels in active lesions and in microscopically inflamed vessels in NAWM. Dual fluorescence revealed abnormal TJs in vessels with pre‐mortem serum protein leakage. Abnormal or open TJs, associated with inflammation may contribute to BBB leakage in enhancing MRI lesions and may also be involved in subtle leakage in non‐enhancing focal and diffuse lesions in NAWM. BBB disruption due to tight junctional pathology should be regarded as a significant form of tissue injury in MS, alongside demyelination and axonopathy.