Jian-Qiang Lu

Multiple Sclerosis: Validation of MR Imaging for Quantification and Detection of Iron

PURPOSE To investigate the relationship between iron staining and magnetic resonance (MR) imaging measurements in postmortem subjects with multiple sclerosis (MS). MATERIALS AND METHODS Institutional ethical approval was obtained, and informed consent was obtained from the subjects and/or their families. Four MR imaging methods based on transverse relaxation (T2 weighting, R2 mapping, and R2* mapping) and phase imaging were performed by using a 4.7-T system in three in situ postmortem patients with MS less than 28 hours after death and in one in vivo patient 1 year before death. Iron staining with the Perls iron reaction was performed after brain extraction. Region-of-interest measurements from six subcortical gray matter structures were obtained from MR imaging and then correlated with corresponding locations on photographs of iron-stained pathologic slices by using a separate linear least-squares regression in each subject. Iron status of white matter lesions, as determined by staining, was compared with appearance on MR images. RESULTS R2* mapping had the highest intrasubject correlations with iron in subcortical gray matter (R(2) = 0.857, 0.628, and 0.685; all P < .001), while R2 mapping (R(2) = 0.807, 0.615, 0.628, and 0.489; P < .001 and P = .001, .034, and .001, respectively), phase imaging (R(2) = 0.672, 0.441, 0.596, 0.548; all P ≤ .001), and T2-weighted imaging (R(2) = 0.463, 0.582, 0.650, and 0.551; all P < .001) had lower but still strong correlations. Within lesions, hypointense areas on phase images did not always represent iron. A hyperintense rim surrounding lesions on R2* maps was only present with iron staining, yet not all iron-staining lesions had R2* rim hyperintensity. CONCLUSION All four MR imaging methods had significant linear correlations with iron and could potentially be used to determine iron status of subcortical gray matter structures in MS, with R2* mapping being preferred. A reliable method of determining iron status within MS lesions was not established.

Neuroinflammation and demyelination in multiple sclerosis after allogeneic hematopoietic stem cell transplantation.

OBJECTIVE To evaluate the effects of allogeneic hematopoietic stem cell transplantation (allo-HSCT) on the brains of persons with and without multiple sclerosis (MS) by means of postmortem histopathological examination. DESIGN Postmortem histopathology, case studies, and case-control studies. Patients Four patients with MS who died at a median of 4.5 months (range, 3-9 months) after allo-HSCT for a concomitant hematologic malignant neoplasm; 5 patients without MS who died at a median of 10.0 months (1-29 months) after allo-HSCT; and 5 control subjects without MS who did not undergo allo-HSCT. SETTING Referral centers. Intervention Allogeneic hematopoietic stem cell transplantation. MAIN OUTCOME MEASURES Morphological features and immunohistochemical features, including the quantitative measures of chronic inflammatory cells. RESULTS Demyelinating and inflammatory activities of MS persisted after allo-HSCT in all of the patients with MS. Active and chronic active MS lesions exhibited significantly higher numbers of CD3+ T cells and CD8+ cytotoxic T cells and significantly higher scores of CD68+ microglia/macrophages than did chronic inactive lesions or normal-appearing white matter. The normal-appearing brains of allo-HSCT recipients who did not have MS were found to have significantly higher numbers of CD3+ T cells and CD8+ cytotoxic T cells and higher scores of CD68+ microglia/macrophages compared with the controls; however, no demyelination was identified in these non-MS samples. CONCLUSION Allo-HSCT fails to halt the demyelination and inflammation of MS.

Granule-Derived Granzyme B Mediates the Vulnerability of Human Neurons to T Cell-Induced Neurotoxicity

Multiple sclerosis (MS) is considered an autoimmune disease of the CNS and is characterized by inflammatory cells infiltrating the CNS and inducing demyelination, axonal loss, and neuronal death. Recent evidence strongly suggests that axonal and neuronal degeneration underlie the progression of permanent disability in MS. In this study, we report that human neurons are selectively susceptible to the serine-protease granzyme B (GrB) isolated from cytotoxic T cell granules. In vitro, purified human GrB induced neuronal death to the same extent as the whole activated T cell population. On the contrary, activated T cells isolated from GrB knockout mice failed to induce neuronal injury. We found that following internalization through various parts of neurons, GrB accumulated in the neuronal soma. Within the cell body, GrB diffused out of endosomes possibly through a perforin-independent mechanism and induced subsequent activation of caspases and cleavage of α-tubulin. Inhibition of caspase-3, a well-known substrate for GrB, significantly reduced GrB-mediated neurotoxicity. We demonstrated that treatment of neurons with mannose-6-phosphate prevented GrB entry and inhibited GrB-mediated neuronal death, suggesting mannose-6-phosphate receptor-dependent endocytosis. Together, our data unveil a novel mechanism by which GrB induces selective neuronal injury and suggest potential new targets for the treatment of inflammatory-mediated neurodegeneration in diseases such as MS.

Brain microbiota disruption within inflammatory demyelinating lesions in multiple sclerosis

Microbial communities reside in healthy tissues but are often disrupted during disease. Bacterial genomes and proteins are detected in brains from humans, nonhuman primates, rodents and other species in the absence of neurological disease. We investigated the composition and abundance of microbiota in frozen and fixed autopsied brain samples from patients with multiple sclerosis (MS) and age- and sex-matched nonMS patients as controls, using neuropathological, molecular and bioinformatics tools. 16s rRNA sequencing revealed Proteobacteria to be the dominant phylum with restricted diversity in cerebral white matter (WM) from MS compared to nonMS patients. Both clinical groups displayed 1,200–1,400 bacterial genomes/cm3 and low bacterial rRNA:rDNA ratios in WM. RNAseq analyses showed a predominance of Proteobacteria in progressive MS patients’ WM, associated with increased inflammatory gene expression, relative to a broader range of bacterial phyla in relapsing-remitting MS patients’ WM. Although bacterial peptidoglycan (PGN) and RNA polymerase beta subunit immunoreactivities were observed in all patients, PGN immunodetection was correlated with demyelination and neuroinflammation in MS brains. Principal component analysis revealed that demyelination, PGN and inflammatory gene expression accounted for 86% of the observed variance. Thus, inflammatory demyelination is linked to an organ-specific dysbiosis in MS that could contribute to underlying disease mechanisms.

Continued Disease Activity in a Patient With Multiple Sclerosis After Allogeneic Hematopoietic Cell Transplantation

OBJECTIVE To examine the effect of allogeneic hematopoietic cell transplantation (HCT) on disease activity in a patient with multiple sclerosis (MS). DESIGN Case report, prospective study, and autopsy. SETTING Departments of Clinical Neurosciences, Internal Medicine, and Pathology at the University of Calgary, Alberta, Canada. PATIENT A 39-year-old woman with chronic myelogenous leukemia and concurrent mild MS. INTERVENTIONS Hematopoietic cell transplantation from a healthy unrelated donor. RESULTS After HCT the patient developed graft-vs-host disease and experienced worsening, but not new, neurological symptoms. Her circulating leukocytes were 100% of donor origin. Magnetic resonance imaging showed increased lesion burden. She died of adenovirus hepatitis 20 weeks after HCT. An autopsy revealed demyelinating-inflammatory activity in active lesions and chronic active lesions. CONCLUSION Despite high-dose, cytotoxic, immunosuppressive therapy and exchange of a presumed autoreactive immune system with a healthy immune system, MS in this patient continued to be active.

Association of α-Synuclein Immunoreactivity With Inflammatory Activity in Multiple Sclerosis Lesions

Multiple sclerosis (MS) has neurodegenerative features including neuronal and axonal loss and widespread atrophy of the brain and spinal cord. The cause of this neurodegeneration has been largely attributed to inflammation, but other mechanisms, including those associated with classic neurodegenerative diseases such as the &agr;-synucleinopathies, might also be involved in MS pathogenesis. In this study, 96 brain lesions containing varying degrees of inflammatory activity from 12 autopsied MS cases were compared with corresponding regions from 6 neuropathologically normal controls; 2 cerebral biopsy lesions from an MS patient were also studied. We found &agr;-synuclein immunoreactivity in the cytoplasm of cells in MS lesions with inflammatory activity but not in control samples. &agr;-Synuclein-immunoreactive cells were identified in active (15/15 lesions in the brainstem, 9/13 in cerebral hemispheres) and chronic active (14/15 in the brainstem, 12/22 in cerebral hemispheres) lesions but were absent in chronic inactive lesions (0/31); the greater immunoreactivity in brainstem compared with cerebral hemisphere lesions was significant (p < 0.05). Double-immunofluorescence staining revealed localization of &agr;-synuclein immunoreactivity mostly in neurons, microglia/macrophages, and oligodendrocytes, and only rarely in astrocytes. The results suggest that &agr;-synuclein expression regulated by inflammatory signals may contribute to neurodegenerative processes in MS lesions.

Multifocal complex glioneuronal tumor in an elderly man: An autopsy study: Case report

OBJECTIVEThe clinicopathological spectra of a dysembryoplastic neuroepithelial tumor (DNT) and a rosette-forming glioneuronal tumor (RGNT) are expanding. We report here the autopsy findings of a case of complex glioneuronal tumor with combined histological features of both a DNT and an RGNT. CLINICAL PRESENTATIONA 79-year-old man presented with a 1-month history of confusion and gait difficulties. A magnetic resonance imaging scan revealed obstructive hydrocephalus attributed to a mass in the posterior third ventricle. INTERVENTIONA third ventriculostomy was performed. Postoperatively, the mass remained unchanged in size for more than 14 months. Thirty-eight months after his initial manifestations, he experienced minor head trauma and was then hospitalized. Despite placement of an external ventricular drain and other supportive treatment, he deteriorated and died. A full autopsy was performed, with emphasis on the brain. The mass lesion and a few independent microfoci situated primarily around the third ventricle showed histological features of pilocytic astrocytoma with recurrent hemorrhage. Far more numerous were microfoci with histological features of a DNT, including floating neurons, as well as typical RGNT-associated, synaptophysin-positive rosettes and perivascular pseudorosettes. CONCLUSIONThe advanced age of the patient, the coexisting histological features of the DNT and RGNT, and the distinctive anatomic distribution of the lesions, being centered on the third ventricle, may lend insight into the histogenetic relationship of a DNT, an RGNT, and mixed glioneuronal tumors.

Tumor-to-tumor metastasis: esophageal carcinoma metastatic to an intracranial paraganglioma

Tumor-to-tumor metastasis (TTM) is a relatively rare but well-documented phenomenon. The authors report a unique case of esophageal carcinoma metastatic to an intracranial paraganglioma. A sellar and suprasellar tumor was found using MR imaging in an 81-year-old man who presented with a 3-week history of progressive headache and blurred vision. A subtotal excision of the tumor was achieved. Histopathological examination of the tumor disclosed a neoplasm with two distinct components: one showing the classic Zellballen pattern of a paraganglioma, the other exhibiting malignant features leading to the diagnosis of a poorly differentiated carcinoma metastatic to a sellar/suprasellar paraganglioma. The primary esophageal carcinoma was not uncovered until 2 months later, after the patient presented with upper gastrointestinal bleeding. The patient died 4 months after initial presentation. This case expands the spectrum of TTM, and emphasizes the importance of TTM in the practice of pathology.

Rab32 connects ER stress to mitochondrial defects in multiple sclerosis

BackgroundEndoplasmic reticulum (ER) stress is a hallmark of neurodegenerative diseases such as multiple sclerosis (MS). However, this physiological mechanism has multiple manifestations that range from impaired clearance of unfolded proteins to altered mitochondrial dynamics and apoptosis. While connections between the triggering of the unfolded protein response (UPR) and downstream mitochondrial dysfunction are poorly understood, the membranous contacts between the ER and mitochondria, called the mitochondria-associated membrane (MAM), could provide a functional link between these two mechanisms. Therefore, we investigated whether the guanosine triphosphatase (GTPase) Rab32, a known regulator of the MAM, mitochondrial dynamics, and apoptosis, could be associated with ER stress as well as mitochondrial dysfunction.MethodsWe assessed Rab32 expression in MS patient and experimental autoimmune encephalomyelitis (EAE) tissue, via observation of mitochondria in primary neurons and via monitoring of survival of neuronal cells upon increased Rab32 expression.ResultsWe found that the induction of Rab32 and other MAM proteins correlates with ER stress proteins in MS brain, as well as in EAE, and occurs in multiple central nervous system (CNS) cell types. We identify Rab32, known to increase in response to acute brain inflammation, as a novel unfolded protein response (UPR) target. High Rab32 expression shortens neurite length, alters mitochondria morphology, and accelerates apoptosis/necroptosis of human primary neurons and cell lines.ConclusionsER stress is strongly associated with Rab32 upregulation in the progression of MS, leading to mitochondrial dysfunction and neuronal death.

Suppressed oligodendrocyte steroidogenesis in multiple sclerosis: Implications for regulation of neuroinflammation

Multiple sclerosis (MS) is an inflammatory demyelinating disease of the central nervous system (CNS). Neurosteroids are reported to exert anti‐inflammatory effects in several neurological disorders. We investigated the expression and actions of the neurosteroid, dehydroepiandrosterone (DHEA), and its more stable 3β‐sulphated ester, DHEA‐S, in MS and associated experimental models. CNS tissues from patients with MS and animals with experimental autoimmune encephalomyelitis (EAE) displayed reduced DHEA concentrations, accompanied by diminished expression of the DHEA‐synthesizing enzyme CYP17A1 in oligodendrocytes (ODCs), in association with increased expression of inflammatory genes including interferon (IFN)‐γ and interleukin (IL)‐1β. CYP17A1 was expressed variably in different human neural cell types but IFN‐γ exposure selectively reduced CYP17A1 detection in ODCs. DHEA‐S treatment reduced IL‐1β and −6 release from activated human myeloid cells with minimal effect on lymphocyte viability. Animals with EAE receiving DHEA‐S treatment showed reduced Il1b and Ifng transcript levels in spinal cord compared to vehicle‐treated animals with EAE. DHEA‐S treatment also preserved myelin basic protein immunoreactivity and reduced axonal loss in animals with EAE, relative to vehicle‐treated EAE animals. Neurobehavioral deficits were reduced in DHEA‐S‐treated EAE animals compared with vehicle‐treated animals with EAE. Thus, CYP17A1 expression in ODCs and its product DHEA were downregulated in the CNS during inflammatory demyelination while DHEA‐S provision suppressed neuroinflammation, demyelination, and axonal injury that was evident as improved neurobehavioral performance. These findings indicate that DHEA production is an immunoregulatory pathway within the CNS and its restoration represents a novel treatment approach for neuroinflammatory diseases.