Anacardic acid induces IL-33 and promotes remyelination in CNS.

Given the known neuroreparative actions of IL-33 in experimental models of central nervous system (CNS) injury, we predicted that compounds which induce IL-33 are likely to promote remyelination. We found anacardic acid as a candidate molecule to serve as a therapeutic agent to promote remyelination. Addition of anacardic acid to cultured oligodendrocyte precursor cells (OPCs) rapidly increased expression of myelin genes and myelin proteins, suggesting a direct induction of genes involved in myelination by anacardic acid. Also, when added to OPCs, anacardic acid resulted in the induction of IL-33. In vivo, treatment of with anacardic acid in doses which ranged from 0.025 mg/kg to 2.5 mg/kg, improved pathologic scores in experimental allergic encephalitis (EAE) and in the cuprizone model of demyelination/remyelination. Electron microscopic studies performed in mice fed with cuprizone and treated with anacardic acid showed lower g-ratio scores when compared to controls, suggesting increased remyelination of axons. In EAE, improvement in paralytic scores was seen when the drug was given prior to or following the onset of paralytic signs. In EAE and in the cuprizone model, areas of myelin loss, which are likely to remyelinate, was associated with a greater recruitment of IL-33-expressing OPCs in mice which received anacardic acid when compared to controls.

Endogenous double-stranded Alu RNA elements stimulate IFN-responses in relapsing remitting multiple sclerosis.

Various sensors that detect double-stranded RNA, presumably of viral origin, exist in eukaryotic cells and induce IFN-responses. Ongoing IFN-responses have also been documented in a variety of human autoimmune diseases including relapsing-remitting multiple sclerosis (RRMS) but their origins remain obscure. We find increased IFN-responses in leukocytes in relapsing-remitting multiple sclerosis at distinct stages of disease. Moreover, endogenous RNAs isolated from blood cells of these same patients recapitulate this IFN-response if transfected into naïve cells. These endogenous RNAs are double-stranded RNAs, contain Alu and Line elements and are transcribed from leukocyte transcriptional enhancers. Thus, transcribed endogenous retrotransposon elements can co-opt pattern recognition sensors to induce IFN-responses in RRMS.

Multiple sclerosis lesions affect intrinsic functional connectivity of the spinal cord.

Patients with multiple sclerosis present with focal lesions throughout the spinal cord. There is a clinical need for non-invasive measurements of spinal cord activity and functional organization in multiple sclerosis, given the cord's critical role in the disease. Recent reports of spontaneous blood oxygenation level-dependent fluctuations in the spinal cord using functional MRI suggest that, like the brain, cord activity at rest is organized into distinct, synchronized functional networks among grey matter regions, likely related to motor and sensory systems. Previous studies looking at stimulus-evoked activity in the spinal cord of patients with multiple sclerosis have demonstrated increased levels of activation as well as a more bilateral distribution of activity compared to controls. Functional connectivity studies of brain networks in multiple sclerosis have revealed widespread alterations, which may take on a dynamic trajectory over the course of the disease, with compensatory increases in connectivity followed by decreases associated with structural damage. We build upon this literature by examining functional connectivity in the spinal cord of patients with multiple sclerosis. Using ultra-high field 7 T imaging along with processing strategies for robust spinal cord functional MRI and lesion identification, the present study assessed functional connectivity within cervical cord grey matter of patients with relapsing-remitting multiple sclerosis (n = 22) compared to a large sample of healthy controls (n = 56). Patient anatomical images were rated for lesions by three independent raters, with consensus ratings revealing 19 of 22 patients presented with lesions somewhere in the imaged volume. Linear mixed models were used to assess effects of lesion location on functional connectivity. Analysis in control subjects demonstrated a robust pattern of connectivity among ventral grey matter regions as well as a distinct network among dorsal regions. A gender effect was also observed in controls whereby females demonstrated higher ventral network connectivity. Wilcoxon rank-sum tests detected no differences in average connectivity or power of low frequency fluctuations in patients compared to controls. The presence of lesions was, however, associated with local alterations in connectivity with differential effects depending on columnar location. The patient results suggest that spinal cord functional networks are generally intact in relapsing-remitting multiple sclerosis but that lesions are associated with focal abnormalities in intrinsic connectivity. These findings are discussed in light of the current literature on spinal cord functional MRI and the potential neurological underpinnings.

Improved diffusion tensor imaging of the optic nerve using multishot two-dimensional navigated acquisitions.

PURPOSE: A diffusion-weighted multishot echo-planar imaging approach combined with SENSE and a two-dimensional (2D) navigated motion correction was investigated as an alternative to conventional single-shot counterpart to obtain optic nerve images at higher spatial resolution with reduced artifacts. METHODS: Fifteen healthy subjects were enrolled in the study. Six of these subjects underwent a repeated acquisition at least 2 weeks after the initial scan session to address reproducibility. Both single-shot and multishot diffusion tensor imaging studies of the human optic nerve were performed with matched scan time. Effect of subject motions were corrected using 2D phase navigator during multishot image reconstruction. Tensor-derived indices from proposed multishot were compared against conventional single-shot approach. Image resolution difference, right-left optic nerve asymmetry, and test-retest reproducibility were also assessed. RESULTS: In vivo results of acquired multishot images and quantitative maps of diffusion properties of the optic nerve showed significantly reduced image artifacts (e.g., distortions and blurring), and the derived diffusion indices were comparable to those from other studies. Single-shot scans presented larger variability between right and left optic nerves than multishot scans. Multishot scans also presented smaller variations across scans at different time points when compared with single-shot counterparts. CONCLUSION: The multishot technique has considerable potential for providing improved information on optic nerve pathology and may also be translated to higher fields.

Influence of preprocessing, distortion correction and cardiac triggering on the quality of diffusion MR images of spinal cord.

Diffusion MRI of the spinal cord (SC) is susceptible to geometric distortion caused by field inhomogeneities, and prone to misalignment across time series and signal dropout caused by biological motion. Several modifications of image acquisition and image processing techniques have been introduced to overcome these artifacts, but their specific benefits are largely unproven and warrant further investigations. We aim to evaluate two specific aspects of image acquisition and processing that address image quality in diffusion studies of the spinal cord: susceptibility corrections to reduce geometric distortions, and cardiac triggering to minimize motion artifacts. First, we evaluate 4 distortion preprocessing strategies on 7 datasets of the cervical and lumbar SC and find that while distortion correction techniques increase geometric similarity to structural images, they are largely driven by the high-contrast cerebrospinal fluid, and do not consistently improve the geometry within the cord nor improve white-to-gray matter contrast. We recommend at a minimum to perform bulk-motion correction in preprocessing and posit that improvements/adaptations are needed for spinal cord distortion preprocessing algorithms, which are currently optimized and designed for brain imaging. Second, we design experiments to evaluate the impact of removing cardiac triggering. We show that when triggering is foregone, images are qualitatively similar to triggered sequences, do not have increased prevalence of artifacts, and result in similar diffusion tensor indices with similar reproducibility to triggered acquisitions. When triggering is removed, much shorter acquisitions are possible, which are also qualitatively and quantitatively similar to triggered sequences. We suggest that removing cardiac triggering for cervical SC diffusion can be a reasonable option to save time with minimal sacrifice to image quality.

Astrogliopathy and oligodendrogliopathy are early events in CNS demyelination.

We examined the phenotypic composition of cells and the underlying mechanisms of demyelination following injection of lipopolysaccharide (LPS) into the corpus callosum of rats. Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay showed fragmented DNA, which co-localized with oligodendrocytes in areas of demyelination following intracerebral injection with LPS. Immunostaining showed the presence of caspase 3 in cells which expressed the oligodendrocyte markers, suggesting activation of the apoptotic pathway. Commensurate reduction in glial fibrillary acid protein (GFAP)+/ gap junction protein connexin43+ (Cx43) cells, was also seen in the corpus callosum prior to histochemical evidence of demyelination. Expression of mRNA for proinflammatory cytokines was maximal 3 day postinjection, at a time when the numbers of TUNEL positive cells in the corpus callosum were declining and the total number of CD68+ cells peaked at day 14 postinjection. Our studies suggest that death of oligodendrocytes is an early event in LPS model of demyelination. We believe that the innate immune model of oligodendrocyte death will be useful in the development of neuroprotective agents capable of rescuing oligodendrocytes from apoptosis.

Inhibition of SUMOylation promotes remyelination and reduces IL-17 mediated autoimmune inflammation: Novel approach toward treatment of inflammatory CNS demyelinating disease.

Small ubiquitin like modifiers (SUMO) are reversible posttranslational modifiers of intracellular proteins. In the CNS, expression of myelin genes is regulated by state of SUMOylation of their respective transcription factors. In the immune system, deSUMOylation activates innate immune responses and promotes anti-viral immunity. However, the role played by SUMO in an adaptive immune response and in the development of T cell mediated autoimmune disease has not been previously described. TAK981 is a synthetic small molecule which by forming adducts with SUMO proteins prevents SUMOylation. We examined the expression of myelin genes and their transcription factors following culture with TAK981 in Oligodendrocyte Precursor Cells (OPC). We found that myelin basic protein (MBP), a key myelin protein, is upregulated in OPC in the presence of TAK981. We also found increased expression of transcription factors Sox10 and Myrf, which engage in the expression of MBP. In the Cuprizone model of demyelination/remyelination, animals which were treated with TAK981 showed increased remyelination in areas of demyelination and an increase in the number of maturing oligodendrocytes compared to vehicle treated controls. In in vitro cultures of lymphocytes, TAK981 reduced the expression of TH17 in T cells in mice immunized with MOGp35-55. Following in vivo treatment with TAK981, there was a significant reduction in the clinical and pathological severity in mice immunized to develop experimental allergic encephalitis (EAE). The dual effects of deSUMOylation on remyelination and in regulating an autoimmune adaptive response offers a novel approach to the management of human inflammatory demyelinating diseases such as multiple sclerosis.

Development of chemical exchange saturation transfer at 7 T.

Chemical exchange saturation transfer (CEST) MRI is a molecular imaging method that has previously been successful at reporting variations in tissue protein and glycogen contents and pH. We have implemented amide proton transfer (APT), a specific form of chemical exchange saturation transfer imaging, at high field (7 T) and used it to study healthy human subjects and patients with multiple sclerosis. The effects of static field inhomogeneities were mitigated using a water saturation shift referencing method to center each z-spectrum on a voxel-by-voxel basis. Contrary to results obtained at lower fields, APT imaging at 7 T revealed significant contrast between white and gray matters, with a higher APT signal apparent within the white matter. Preliminary studies of multiple sclerosis showed that the APT asymmetry varied with the type of lesion examined. An increase in APT asymmetry relative to healthy tissue was found in some lesions. These results indicate the potential utility of APT at high field as a noninvasive biomarker of white matter pathology, providing complementary information to other MRI methods in current clinical use.

Intrathecal methotrexate - Another tool for the treatment of refractory autoimmune encephalitis - Single institution cohort and literature review.

BACKGROUND: Autoimmune encephalitis (AIE) encompasses a range of inflammatory disorders manifesting with some combination of encephalopathy, seizures, behavioral changes, movement disorders, dysautonomia or other neurologic symptoms. Anti-N-methyl-d-aspartate receptor encephalitis (NMDARE) is the most common AIE and is an autoantibody mediated disorder, often paraneoplastic. Untreated or undertreated AIE has a high degree of morbidity and mortality. Immunosuppressive treatment regimens including glucocorticoids, plasma exchange (PLEX), intravenous immunoglobulin (IVIG) and rituximab used alone or in combination for such patients. Patients' refractory to such treatments requires more aggressive and potentially toxic therapies. We report favorable outcomes in patients with refractory AIE who received intrathecal methotrexate (IT-MTX) as part of treatment. METHODS: Cases at our institution seen between 2010 and 2020 were reviewed. We identified 5 patients in our clinical practice whose clinical presentation was compatible with NMDARE. Three patients met criteria for definite NMDARE. An additional two patients met criteria for probable NMDARE in the acute setting but were ultimately seronegative autoimmune encephalitis. All patients received at least one dose of IT-MTX after failing conventional therapies. At the time of IT-MTX administration patients were catatonic, comatose, or severely encephalopathic despite initial treatments. RESULTS: All patients were treated with methylprednisolone; 3 received a course of IVIG, 4 underwent PLEX, and 4 received rituximab. At the time IT-MTX was given, three patients required mechanical ventilation and 1 had a pacemaker placed for autonomic failure. Two patients were under consideration for transition to palliative care. All patients improved and were at or near their premorbid baseline at last follow-up. All patients tolerated IT-MTX well. CONCLUSIONS: This retrospective review demonstrates the efficacy of intrathecal methotrexate in the treatment of severe AIE who had failed other immunosuppressive regimens.

Chlamydia pneumoniae infection of the central nervous system worsens experimental allergic encephalitis.

Experimental allergic encephalitis (EAE) is considered by many to be a model for human multiple sclerosis. Intraperitoneal inoculation of mice with Chlamydia pneumoniae, after immunization with neural antigens, increased the severity of EAE. Accentuation of EAE required live infectious C. pneumoniae, and the severity of the disease was attenuated with antiinfective therapy. After immunization with neural antigens, systemic infection with C. pneumoniae led to the dissemination of the organism into the central nervous system (CNS) in mice with accentuated EAE. Inoculation with Chlamydia trachomatis did not worsen EAE and infectious organisms were not seen in the CNS. These observations suggest that dissemination of C. pneumoniae results in localized infection in CNS tissues in animals with EAE. We propose that infection of the CNS by C. pneumoniae can amplify the autoreactive pool of lymphocytes and regulate the expression of an autoimmune disease.

Identification and characterization of the interferon-beta-mediated p53 signal pathway in human peripheral blood mononuclear cells.

The relationship between the p53 signal pathway and the response of human peripheral blood mononuclear cells (PBMC) to interferon (IFN)-beta has hitherto not been examined. Using an oligonucleotide microarray, we found differential expression of at least 70 genes involved in the p53 signal pathway, including p53, which regulate cell proliferation and cell death following stimulation with IFN-beta. We verified our observations on a limited set of p53-regulated genes at the transcriptional and translational levels. We also examined the consequences of the activation of the p53 signal pathway by IFN-beta in PBMC. When cultured in the presence of T-cell mitogens, IFN-beta restricted the entry of lymphocytes from the G0/G1 phase to the S phase and reduced the number of cells in the G2 phase. The addition of IFN-beta alone did not increase apoptosis. However, in the presence of actinomycin D, a DNA-damaging agent, addition of IFN-beta enhanced the susceptibility of PBMC to apoptosis. These observations suggest that, in spite of the activation of a number of mutually overlapping pathways mediating cell death, cell cycle arrest was the most evident consequence of IFN-beta signalling in PBMC.

Aphasic or amnesic status epilepticus detected on PET but not EEG.

PURPOSE: To describe five patients with ictal aphasia and one patient with ictal amnesia, who had focal positron emission tomography (PET) hypermetabolism but no clear ictal activity on electroencephalography (EEG). METHODS: (18)F-Fluorodeoxyglucose (FDG)-PET scans with concomitant EEG were obtained in five patients with suspected ictal aphasia or ictal amnesia without ictal activity on EEG. We reviewed medical history, EEG, imaging data, and treatment outcome. RESULTS: Brain magnetic resonance imaging (MRI) showed no structural abnormalities in any of the patients. EEG showed left temporal irregular delta activity in three patients, with aphasia and nonspecific abnormalities in two other patients, all without clear ictal pattern. All patients demonstrated focal hypermetabolism on PET scan. The hypermetabolism was in the left frontotemporal region in patients with ictal aphasia and in the bilateral hippocampal region in the patient with amnesia. Three patients who received intravenous benzodiazepines during their episodes had transient clinical improvement. With antiepileptic drug (AED) treatment, symptoms gradually resolved in all patients. Concomitant resolution of PET hypermetabolism was documented in three patients who had follow up scans. One patient with ictal aphasia later developed recurrent episodes, each with recurrent PET hypermetabolism. This patient and one other patient required immune-modulating therapy in addition to AEDs. DISCUSSION: FDG-PET imaging should be considered as a diagnostic tool in patients with suspected ictal aphasia or amnesia, who fail to show clear evidence of ictal activity on EEG.

Preconditioning with cobalt chloride or desferrioxamine protects oligodendrocyte cell line (MO3.13) from tumor necrosis factor-alpha-mediated cell death.

Hypoxia-inducible factor-1alpha (HIF-1alpha) is a transcription factor induced under hypoxic conditions. HIF-1alpha promotes the expression of genes encoding proteins that increase the cellular supply of oxygen and promote survival in periods of cellular stress and availability of cellular energy. We examined the effect of desferrioxamine (DFO) and cobalt chloride (CoCl(2)), two agents known to increase the stability of HIF-1alpha, and its effect on the survivability of an oligodendroglial cell line, MO3.13, when cultured with tumor necrosis factor-alpha (TNFalpha). Our studies showed that, unlike a murine microglial cell line (BV-2), MO3.13 cells do not induce HIF-1alpha in the presence of TNFalpha. MO3.13 cells do stabilize HIF-1alpha in the presence of DFO or CoCl(2). When MO3.13 cell were preconditioned with either DFO or CoCl(2), addition of TNFalpha further increased protein levels of HIF-1alpha. The mechanisms that underlie the increase in protein levels of HIF -1alpha seen, following addition of TNFalpha in preconditioned cells is due to an increase in transcription of the HIF-1alpha gene. Increased cellular levels of HIF-1alpha is associated with improved survival of MO3.13 cells, when cultured with TNFalpha after a period of preconditioning by DFO or CoCl(2). These studies suggest that compoundsthat increase HIF-1alpha can function as neuroprotective agents in inflammatory disorders of the CNS.

Bacterial cell wall products increases stabilization of HIF-1 alpha in an oligodendrocyte cell line preconditioned by cobalt chloride or desferrioxamine.

We examined the effect of lipopolysaccharide (LPS) or lipotechoic acid (LTA) on the regulation of hypoxia inducible factor (HIF-1) alpha on the MO3.13 cells, a human oligodendroglial cell line. Our study shows that MO3.13 cells express the toll like receptors (TLR's) but do not increase cellular levels of HIF-1 alpha following exposure to bacterial cell wall products. When MO3.13 cells were preconditioned by desferrioxamine (DFO) or cobalt chloride (CoCl(2)) and then treated with either LPS or LTA, HIF-1 alpha levels were higher than that induced by DFO or CoCl(2) alone. The increase in HIF-1 alpha was due to increased protein stability that was mediated by activation of the ERK-MAP kinase pathway.

Tolerability and safety profile of 12- to 28-week treatment with interferon beta-1b 250 and 500 microg QOD in patients with relapsing-remitting multiple sclerosis: a multicenter, randomized, double-blind, parallel-group pilot study.

BACKGROUND: It is not known whether the currently available treatment regimen of interferon beta-1b (IFNbeta-1b) 250 microg provides the maximum benefit possible in the treatment of relapsing-remitting multiple sclerosis (RRMS), or whether higher doses of IFNbeta-1b will prove to be more beneficial. OBJECTIVE: The objective of the present study was to evaluate the tolerability and safety profile of IFNbeta-1b 500 microg compared with the currently approved 250-microg dose. METHODS: A multicenter, randomized, double-blind, parallel-group pilot study was carried out to compare IFNbeta-1b 250 microg with IFNbeta-1b 500 microg, both self-administered SC QOD for >or=12 weeks in patients with RRMS. Patients in both groups started with 25% (0.25 mL) of their final dose and were scheduled to increase the dose by 0.25 mL every 2 weeks, so that the full dose (1.0 mL, 250 microg or 500 microg) would be reached by week 7. The primary outcome measure was the percentage of patients experiencing each of the following adverse events (AEs): influenza-like symptoms (general term used to code the presence of >1 symptom typical of influenza), fever, myalgia, asthenia, headache, injection-site reactions, injection-site pain, or liver or hematologic abnormalities. All patients underwent a priori magnetic resonance imaging (MRI) with 0.1 mmol/kg gadolinium (Gd)-diethylenetriaminepentaacetic acid as contrast medium at screening and at week 12. MRI evaluation was included as a safety measure to monitor for excessive new disease not visible through clinical symptoms. RESULTS: Seventy-seven patients were assessed for inclusion in the study. Of these, 6 patients were screening failures and the remaining 71 were randomized to treatment (38-250 and 33-500 microg IFNbeta-1b). The uneven numbers in the groups were a consequence of the randomization process. Two patients in the 250-microg group (withdrawal of consent) and 1 in the 500-microg group (not completing follow-up visit) prematurely discontinued medication. The demographic characteristics were not significantly different between the 250-microg (n=38; mean [SD] age, 37.9 [8.3] years; weight, 83.5 [19.0] kg; height, 168.4 [9.3] cm) and 500-microg (n=33; mean [SD] age, 37.8 [7.7] years; weight, 82.3 [19.5] kg; height, 169.9 [10.5] cm) treatment groups. The patients in both groups were mostly white (87% and 73%, respectively). Baseline Expanded Disability Status Scale scores also were not significantly different between the 2 groups (mean [SD] score, 2.8 [1.4] vs 2.0 [1.4], respectively). In the IFN(2)-1b 250-microg group, 97% of the patients titrated to the full dose at some point during the course of the study, compared with 91% of the 500-microg group (P=NS). A dose-response effect was observed in some of the more frequent AEs (no. [%]) that included influenza-like syndrome (250-microg group, 13 [34] vs 500-microg group, 16 [48]), asthenia (13 [34] vs 16 [48], respectively), headache (12 [32] vs 12 [36]), myalgia (10 [26] vs 13 [39]), hypesthesia (10 [26] vs 11 [33]), nausea (6 [16] vs 8 [24]), paresthesia (6 [16] vs 8 [24]), myasthenia (4 [11] vs 8 [24]), chills (3 [8] vs 6 [18]), depression (3 [8] vs 5 [15]), back pain (2 [5] vs 5 [15]), increased liver enzymes (4 [11] vs 6 [18]), lymphopenia (4 [11] vs 3 [9]), fever (2 [5] vs 4 [12]), and pain in extremities (1 [3] vs 4 [12]). The between-group incidence of injection-site reactions was not significantly different. No new or unexpected AEs were recorded. Changes in MRI parameters between screening and 12 weeks were not significantly different between dose groups; these included median T2 lesion volume, median Gd-enhanced lesion volume, median Gd-enhanced lesion number, and mean number of newly active lesions. CONCLUSIONS: IFNbeta-1b 500 microg administered SC QOD was generally well tolerated in these patients with RRMS. Large, randomized controlled studies are needed to determine if there are significant differences in MRI end points between the 250- and 500-microg doses.

Longitudinal changes in the expression of IL-33 and IL-33 regulated genes in relapsing remitting MS.

OBJECTIVE: We tested the hypothesis that the expression of IL-33 in MS is dynamic and is likely to reflect the clinical and radiological changes during the course of RRMS. METHODS: MS with either clinical or radiological relapses were recruited for the study and followed for one year. IL-33 and a panel of genes was measured by q PCR and flow cytometry at different time points. RESULTS: Among 22 RRMS patients, 4 patients showed highest levels of IL-33 at the time they were recruited to the study (Month 0); in 14 patients highest levels of IL-33 were seen between 6-11 months after relapse and in 4 patients maximal levels of IL-33 were seen 12 months after relapse. A similar pattern of IL-33 kinetics was seen when IL-33 was measured by flow cytometry in an additional cohort of 12 patients. The timing of the improvement clinically did not correlate with IL-33 expression with highest expression levels either preceding or following clinical recovery. From our whole genome RNA-sequencing data we found a strong correlation between expression levels of IL-33 and a ~2000 mRNA genes. However, none of these genes encoded proteins involved in either innate or adaptive immunity. Rather, many of the genes that correlated highly with IL-33 encoded to proteins involved in DNA repair or mitochondrial function and mRNA splicing pathways. INTERPRETATION: Given the neuro-reparative and remodeling functions attributed to IL-33, it is likely that some of the novel genes we have uncovered may be involved in repair and recovery of the CNS in MS.

Selective Inversion Recovery Quantitative Magnetization Transfer Brain MRI at 7T: Clinical and Postmortem Validation in Multiple Sclerosis.

BACKGROUND AND PURPOSE: An imaging biomarker of myelin integrity is an unmet need in multiple sclerosis (MS). Selective inversion recovery (SIR) quantitative magnetization transfer imaging (qMT) provides assays of myelin content in the human brain. We previously translated the SIR method to 7T and incorporated a rapid turbo field echo (TFE) readout for whole-brain imaging within clinically acceptable scan times. We herein provide histological validation and test in vivo feasibility and applicability of the SIR-TFE protocol in MS. METHODS: Clinical (T1 - and T2 -weighted) and SIR-TFE MRI scans were performed at 7T in a postmortem MS brain and MRI data were acquired in 10 MS patients and 14 heathy volunteers in vivo. The following parameters were estimated from SIR data: the macromolecular-to-free water pool-size-ratio (PSR), the spin-lattice relaxation rate of water (R1f ), and the MT exchange rate (kmf ). Differences in SIR parameters across tissue types, eg, white matter lesions (WM-Ls) and normal appearing WM (NAWM) in patients, and normal white matter (NWM) in heathy volunteers were evaluated. Associations between SIR parameters and disability scores were assessed. RESULTS: For postmortem scans, correspondence was observed between WM-Ls and NAWM from histology and PSR/R1f values. In vivo differences were detected for PSR, R1f , and kmf between WM-Ls and NWM (P ≤ .041). Associations were seen between WM-Ls/ NAWM PSR and disability scores (r ≤ -.671, P ≤ .048). CONCLUSIONS: SIR-qMT at 7T provides sensitive, quantitative measures of myelin integrity for clinical and research applications.

Identification of molecular biomarkers for multiple sclerosis.

Multiple sclerosis is a demyelinating disease of the central nervous system with a presumed autoimmune etiology. Previous microarray analyses identified conserved gene expression signatures in peripheral blood mononuclear cells of patients with autoimmune diseases. We used quantitative real-time polymerase chain reaction analysis to identify a minimum number of genes of which transcript levels discriminated multiple sclerosis patients from patients with other chronic diseases and from controls. We used a computer program to search quantitative transcript levels to identify optimum ratios that distinguished among the different categories. A combination of a 4-ratio equation using expression levels of five genes segregated the multiple sclerosis cohort (n=55) from the control cohort (n=49) with a sensitivity of 91% and specificity of 98%. When autoimmune and other chronic disease groups were included (n=78), this discriminator still performed with a sensitivity of 79% and a specificity of 87%. This approach may have diagnostic utility not only for multiple sclerosis but also for other clinically complex autoimmune diseases.

Infliximab for the treatment of CNS sarcoidosis: A multi-institutional series.

OBJECTIVE: To describe clinical and imaging responses in neurosarcoidosis to infliximab, a monoclonal antibody against tumor necrosis factor-α. METHODS: Investigators at 6 US centers retrospectively identified patients with CNS sarcoidosis treated with infliximab, including only patients with definite or probable neurosarcoidosis following rigorous exclusion of other causes. RESULTS: Of 66 patients with CNS sarcoidosis (27 definite, 39 probable) treated with infliximab for a median of 1.5 years, the mean age was 47.5 years at infliximab initiation (SD 11.7, range 24-71 years); 56.1% were female; 62.1% were white, 37.0% African American, and 3% Hispanic. Sarcoidosis was isolated to the CNS in 19.7%. Using infliximab doses ranging from 3 to 7 mg/kg every 4-8 weeks, MRI evidence of a favorable treatment response was observed in 82.1% of patients with imaging follow-up (n = 56), with complete remission of active disease in 51.8% and partial MRI improvement in 30.1%; MRI worsened in 1 patient (1.8%). There was clinical improvement in 77.3% of patients, with complete neurologic recovery in 28.8%, partial improvement in 48.5%, clinical stability in 18.2%, worsening in 3%, and 1 lost to follow-up. In 16 patients in remission when infliximab was discontinued, the disease recurred in 9 (56%), typically in the same neuroanatomic location. CONCLUSIONS: Most patients with CNS sarcoidosis treated with infliximab exhibit favorable imaging and clinical treatment responses, including some previously refractory to other immunosuppressive treatments. CLASSIFICATION OF EVIDENCE: This study provides Class IV evidence that for patients with CNS sarcoidosis infliximab is associated with favorable imaging and clinical responses.

TLR3 Agonist Poly-IC Induces IL-33 and Promotes Myelin Repair.

BACKGROUND: Impaired remyelination of demyelinated axons is a major cause of neurological disability. In inflammatory demyelinating disease of the central nervous system (CNS), although remyelination does happen, it is often incomplete, resulting in poor clinical recovery. Poly-IC a known TLR3 agonist and IL-33, a cytokine which is induced by poly-IC are known to influence recovery and promote repair in experimental models of CNS demyelination. METHODOLOGY AND PRINCIPAL FINDINGS: We examined the effect of addition of poly-IC and IL-33 on the differentiation and maturation of oligodendrocyte precursor cells (OPC) cultured in vitro. Both Poly-IC and IL-33 induced transcription of myelin genes and the differentiation of OPC to mature myelin forming cells. Poly-IC induced IL-33 in OPC and addition of IL-33 to in vitro cultures, amplified further, IL-33 expression suggesting an autocrine regulation of IL-33. Poly-IC and IL-33 also induced phosphorylation of p38MAPK, a signaling molecule involved in myelination. Following the induction of gliotoxic injury with lysolecithin to the corpus callosum (CC), treatment of animals with poly-IC resulted in greater recruitment of OPC and increased staining for myelin in areas of demyelination. Also, poly-IC treated animals showed greater expression of IL-33 and higher expression of M2 phenotype macrophages in the CC. CONCLUSION/SIGNIFICANCE: Our studies suggest that poly-IC and IL-33 play a role in myelin repair by enhancing expression of myelin genes and are therefore attractive therapeutic agents for use as remyelinating agents in human demyelinating disease.