The Impact of Anti-Amyloid Immunotherapies on Stroke Care.

Anti-amyloid immunotherapies have recently emerged as treatments for Alzheimer's disease. While these therapies have demonstrated efficacy in clearing amyloid-ß and slowing cognitive decline, they have also been associated with amyloid-related imaging abnormalities (ARIA) which include both edema (ARIA-E) and hemorrhage (ARIA-H). Given that ARIA have been associated with significant morbidity in cases of antithrombotic or thrombolytic therapy, an understanding of mechanisms of and risk factors for ARIA is of critical importance for stroke care. We discuss the latest data regarding mechanisms of ARIA, including the role of underlying cerebral amyloid angiopathy, and implications for ischemic stroke prevention and management.

Anti-aquaporin-4 immune complex stimulates complement-dependent Th17 cytokine release in neuromyelitis optica spectrum disorders.

Proinflammatory cytokines, such as (IL: interleukin) IL-6 and IL-17A, and complement fixation are critical in the immunopathogenesis of neuromyelitis optica spectrum disorders (NMOSD). Blocking the IL-6 receptor or the C5 complement pathway reduces relapse risk. However, the role of interleukin (IL)-6 and complement in aquaporin-4 (AQP4) autoimmunity remains unclear. To investigate the role of the anti-AQP4 immunoglobulin (AQP4-IgG)/AQP4 immunocomplex on the induction and profile of ex vivo cytokine and surface marker expression in peripheral blood mononuclear cells (PBMC) culture. Isolated PBMCs obtained from 18 patients with AQP4-IgG-seropositive-NMOSD (8 treatment-naive, 10 rituximab-treated) or ten healthy controls were cultured with AQP4-immunocomplex with or without complement. Changes in PBMC surface markers and cytokine expression were profiled using flow cytometry and ELISA. PBMCs derived from treatment-naive NMOSD patients stimulated with a complex mixture of serum complement proteins produced significant elevations of IL-17A and IL-6. Rituximab-treated patients also exhibited higher IL-6 but not IL-17A release. IL-6 and IL-17A elevations are not observed without complement. Co-stimulation of PBMCs with AQP4-IgG/AQP4 immunocomplex and complement prompts a Th17-biased response consistent with the inflammatory paradigm observed in NMOSD. A possible inflammation model is proposed via antigen-specific autoreactive peripheral blood cells, including NK/NKT cells.

Predictors of relapsing disease course following index event in myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD).

BACKGROUND: Myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) is an autoimmune disease that can present as a monophasic or relapsing disease course. Here, we investigate the predictors of developing relapsing disease with a focus on the index event. METHODS: MOGAD patients followed at Massachusetts General Hospital and Brigham and Women's Hospital were included. Data on demographic, clinical, and laboratory features were collected. Time-to-event survival analysis was performed using a Cox proportional hazards model. Univariate and multivariate regression analyses were performed. RESULTS: We included 124 patients with a diagnosis of MOGAD of which 62.1% (n = 77) were female. The median (IQR) onset age and follow-up time were 31 (16, 45), and 4.08 (2.2, 7.9) years respectively. In total, 40.3% (n = 50) of patients remained monophasic and, 59.7% (n = 74) developed a relapsing course. The median (IQR) time between the index event and the second attack was 3(2, 13.7) months. Starting maintenance therapy following the index event was associated with decreased risk of relapsing disease (HR:0.26; 95%CI: 0.12, 0.54; P < 0.001). Maintenance therapy with intravenous immunoglobulin (HR:0.1; 95% CI:0.01, 0.78, P = 0.02), rituximab (HR: 0.21; 95%CI: 0.08, 0.55; P = 0.001), and mycophenolate mofetil (HR: 0.27; 95%CI: 0.09, 0.77; P = 0.01) was associated with a decreased risk of relapsing disease course. A polyphasic first attack (HR:2.4; 95%CI:1.31, 4.4; P = 0.004) and high CSF protein (HR:2.06; 95%CI: 1.01, 4.16; P = 0.04) were associated with a relapsing course. CONCLUSIONS: In MOGAD patients, starting maintenance therapy following the index event reduces the risk of relapsing disease regardless of age, sex, and onset phenotype, while polyphasic first attack, and elevated CSF protein predict relapsing disease course.

MOG-IgG myelitis coexisting with systemic lupus erythematosus in the post-partum setting.

BACKGROUND: Longitudinally extensive transverse myelitis (LETM) accompanying systemic lupus erythematosus (SLE) is often due to coexisting aquaporin-4-IgG seropositive neuromyelitis optica spectrum disorder but has not been associated with myelin oligodendrocyte glycoprotein-IgG (MOG-IgG). OBJECTIVE AND METHODS: Case report at an academic medical center. RESULTS: A 32-year-old woman developed severe transverse myelitis (paraplegia) shortly after SLE onset in the post-partum period. Magnetic resonance imaging (MRI) revealed an LETM, cerebrospinal fluid showed marked inflammation, and testing for infections was negative. Serum live-cell-based assay for MOG-IgG was positive but aquaporin-4-IgG was negative. CONCLUSION: In patients with SLE and LETM, MOG-IgG testing should be considered, in addition to AQP4-IgG.

Distinct Function-Related Molecular Profile of Adult Human A2B5-Positive Pre-Oligodendrocytes Versus Mature Oligodendrocytes.

Remyelination in the human CNS is ascribed to progenitor cells rather than previously myelinating oligodendrocytes (OLs). The ganglioside-recognizing antibody A2B5 has been used to isolate putative progenitor cells, whose in vitro features resemble cells labeled as "pre-oligodendrocytes." Here, we compare the transcriptional profiles of adult human brain-derived A2B5 antibody-selected cells (A+) after initial isolation (day in vitro (DIV1)) and after DIV6, with nonselected (A-) cells (mature OLs), with regard to their differentiation state and functional properties. While a number of previously recognized progenitor associated genes, specifically PTPRZ1 and PDGFRα, were upregulated in the A2B5+ population, a number of such genes were comparably expressed in the mature OLs, as were mature myelin genes. Additional progenitor-related genes were upregulated in the A+ population. We show that A2B5+ cells have greater capacity to ensheath nanofibers, a model of myelination potential; consistent with this, ingenuity pathway analysis indicated that A+ cells had upregulated expression of genes within cell growth and cell signaling pathways. Differential expression of cell death/survival pathways complements previous functional studies showing their increased susceptibility to metabolic stress. At DIV6, we observed significantly fewer differentially expressed genes; suggestive of cell maturation occurring in vitro, indicating the complexity in comparing in vitro and in situ cell properties.

The ubiquitin proteasome system in atrophying skeletal muscle: roles and regulation.

Muscle atrophy complicates many diseases as well as aging, and its presence predicts both decreased quality of life and survival. Much work has been conducted to define the molecular mechanisms involved in maintaining protein homeostasis in muscle. To date, the ubiquitin proteasome system (UPS) has been shown to play an important role in mediating muscle wasting. In this review, we have collated the enzymes in the UPS whose roles in muscle wasting have been confirmed through loss-of-function studies. We have integrated information on their mechanisms of action to create a model of how they work together to produce muscle atrophy. These enzymes are involved in promoting myofibrillar disassembly and degradation, activation of autophagy, inhibition of myogenesis as well as in modulating the signaling pathways that control these processes. Many anabolic and catabolic signaling pathways are involved in regulating these UPS genes, but none appear to coordinately regulate a large number of these genes. A number of catabolic signaling pathways appear to instead function by inhibition of the insulin/IGF-I/protein kinase B anabolic pathway. This pathway is a critical determinant of muscle mass, since it can suppress key ubiquitin ligases and autophagy, activate protein synthesis, and promote myogenesis through its downstream mediators such as forkhead box O, mammalian target of rapamycin, and GSK3ß, respectively. Although much progress has been made, a more complete inventory of the UPS genes involved in mediating muscle atrophy, their mechanisms of action, and their regulation will be useful for identifying novel therapeutic approaches to this important clinical problem.