Open AccessMetachromatic leukodystrophy and transplantation: remyelination, no cross‐correction
Author(s) -
Wolf Nicole I.,
Breur Marjolein,
Plug Bonnie,
Beerepoot Shanice,
Westerveld Aimee S. R.,
Rappard Diane F.,
Vries Sharon I.,
Kole Maarten H. P.,
Vanderver Adeline,
Knaap Marjo S.,
Lindemans Caroline A.,
Hasselt Peter M.,
Boelens Jaap J.,
Matzner Ulrich,
Gieselmann Volkmar,
Bugiani Marianna
Publication year - 2020
Publication title -
annals of clinical and translational neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.824
H-Index - 42
ISSN - 2328-9503
DOI - 10.1002/acn3.50975
Subject(s) - metachromatic leukodystrophy , remyelination , arylsulfatase a , transplantation , myelin , multiple sclerosis , white matter , pathology , medicine , leukodystrophy , oligodendrocyte , immunology , hematopoietic stem cell transplantation , biology , central nervous system , magnetic resonance imaging , disease , radiology
Abstract Objective In metachromatic leukodystrophy, a lysosomal storage disorder due to decreased arylsulfatase A activity, hematopoietic stem cell transplantation may stop brain demyelination and allow remyelination, thereby halting white matter degeneration. This is the first study to define the effects and therapeutic mechanisms of hematopoietic stem cell transplantation on brain tissue of transplanted metachromatic leukodystrophy patients. Methods Autopsy brain tissue was obtained from eight (two transplanted and six nontransplanted) metachromatic leukodystrophy patients, and two age‐matched controls. We examined the presence of donor cells by immunohistochemistry and microscopy. In addition, we assessed myelin content, oligodendrocyte numbers, and macrophage phenotypes. An unpaired t ‐test, linear regression or the nonparametric Mann–Whitney U ‐test was performed to evaluate differences between the transplanted, nontransplanted, and control group. Results In brain tissue of transplanted patients, we found metabolically competent donor macrophages expressing arylsulfatase A distributed throughout the entire white matter. Compared to nontransplanted patients, these macrophages preferentially expressed markers of alternatively activated, anti‐inflammatory cells that may support oligodendrocyte survival and differentiation. Additionally, transplanted patients showed higher numbers of oligodendrocytes and evidence for remyelination. Contrary to the current hypothesis on therapeutic mechanism of hematopoietic cell transplantation in metachromatic leukodystrophy, we detected no enzymatic cross‐correction to resident astrocytes and oligodendrocytes. Interpretation In conclusion, donor macrophages are able to digest accumulated sulfatides and may play a neuroprotective role for resident oligodendrocytes, thereby enabling remyelination, albeit without evidence of cross‐correction of oligo‐ and astroglia. These results emphasize the importance of immunomodulation in addition to the metabolic correction, which might be exploited for improved outcomes.