Anterior periventricular linear lesions in optic-spinal multiple sclerosis: a combined neuroimaging and neuropathological study

Current perspectives on the link between neuroinflammation and neurogenesis

The link between neuroinflammation and neurogenesis is an area of intensive research in contemporary neuroscience. The burgeoning amount of evidence accumulated over the past decade has been incredible, and now there remains the figuring out of minutia to give us a more complete picture of what individual, synergistic, and antagonistic events are occurring between neurogenesis and neuroinflammation. An intricate study of the inflammatory microenvironment influenced by the presence of the various inflammatory components like cytokines, chemokines, and immune cells is essential for: 1) understanding how neurogenesis can be affected in such a specialized niche and 2) applying the knowledge gained for the treatment of cognitive and/or motor deficits arising from inflammation-associated diseases like stroke, traumatic brain injury, Alzheimer's disease, and Parkinson's disease. This review is written to provide the reader with up-to-date information explaining how these inflammatory components are effecting changes on neurogenesis.

Periventricular lesions help differentiate neuromyelitis optica spectrum disorders from multiple sclerosis

Objective. To compare periventricular lesions in multiple sclerosis (MS) and neuromyelitis optica spectrum disorders (NMOsd). Materials and Methods. Sagittal and axial fluid attenuated inversion recovery (FLAIR) sequences of 20 NMOsd and 40 group frequency-matched MS patients were evaluated by two neuroradiologists. On axial FLAIR, periventricular area was characterized as free of lesions/smooth-bordered ("type A") or jagged-bordered ("type B") pattern. On sagittal FLAIR, the images were evaluated for presence of "Dawson's fingers." Results. Type A pattern was observed in 80% of NMOsd patients by Reader 1 and 85% by Reader 2 but only in 5% MS patients by either Reader. Type B was seen in 15% NMOsd patients by Reader 1 and 20% by Reader 2 and in 95% MS patients by either Reader. Dawson's fingers were observed in no NMOsd patients by Reader 1 and 5% by Reader 2. In MS, Dawson's fingers were seen in 92.5% patients by Reader 1 and 77.5% by Reader 2. The differences in periventricular patterns and Dawson's finger detection between NMOsd and MS were highly significant (P < 0.001). Conclusions. Dawson's fingers and "jagged-bordered" periventricular hyperintensities are typical of MS and almost never seen in NMOsd, which suggests a practical method for differentiating the two diseases.

Clinical characteristics and outcome of multiple sclerosis in Korea: does multiple sclerosis in Korea really differ from that in the Caucasian populations?

Background:

Multiple sclerosis (MS) in Asia is thought to have different clinical characteristics from MS in Western countries; however, previous studies in Asia were performed without properly differentiating neuromyelitis optica (NMO) from MS.

Objectives:

To evaluate the clinical characteristics of MS in Korea after careful exclusion of potential explanations other than MS, particularly NMO spectrum disorder (NMOSD).

Methods:

This study is a retrospective review of consecutive MS patients attending five referral hospitals in Korea. All patients’ MS diagnoses were re-evaluated.

Results:

Of the 105 patients, 70 were female and 35 were male. The mean age of onset was 30.4 years and the mean disease duration was 5.4 years. On initial magnetic resonance imaging (MRI), 58% and 64% fulfilled the criteria for dissemination in space for the 2005 and 2010 McDonald criteria, respectively. Spinal cord lesions were observed in 78% of patients, primarily present as multiple small lesions with a mean length of 0.9 vertebral segments. The median time from disease onset to an Expanded Disability Status Scale 6 was 20 years.

Conclusions:

After careful exclusion of NMOSD, we found that the clinical pattern of MS in Korea does not fundamentally differ from that seen in Western countries.

Activated T-cells inhibit neurogenesis by releasing granzyme B: rescue by Kv1.3 blockers

There is a great need for pharmacological approaches to enhance neural progenitor cell (NPC) function particularly in neuroinflammatory diseases with failed neuroregeneration. In diseases such as multiple sclerosis and stroke, T-cell infiltration occurs in periventricular zones where NPCs are located and is associated with irreversible neuronal loss. We studied the effect of T-cell activation on NPC functions. NPC proliferation and neuronal differentiation were impaired by granzyme B (GrB) released by the T-cells. GrB mediated its effects by the activation of a Gi-protein-coupled receptor leading to decreased intracellular levels of cAMP and subsequent expression of the voltage-dependent potassium channel, Kv1.3. Importantly, blocking channel activity with margatoxin or blocking its expression reversed the inhibitory effects of GrB on NPCs. We have thus identified a novel pathway in neurogenesis. The increased expression of Kv1.3 in pathological conditions makes it a novel target for promoting neurorestoration.

Characteristic linear lesions and longitudinally extensive spinal cord lesions in Chinese patients with neuromyelitis optica

OBJECTIVE

To investigate the characteristics of the linear lesions and longitudinally extensive spinal cord (LESC) lesions in Chinese patients with neuromyelitis optica (NMO).

METHODS

The medical records and magnetic resonance imaging (MRI) scans of 29 patients with NMO were reviewed. The frequencies and distributions of linear and LESC lesions were compared against those displayed by 22 multiple sclerosis (MS) patients. Furthermore, the association of lesions with aquaporin-4 IgG (AQP4-IgG) antibody was investigated.

RESULTS

The NMO patients had significantly more linear lesions than MS patients (48.3 vs 0%, p<0.001). In the NMO group, linear lesions were found in the medulla in 34.5% (10/29) of patients, across the medullospinal region in 10.3% (3/29) and in the spinal cord in 13.8% (4/29). LESC lesions can be seen more frequently in NMO than MS (72.4 vs 22.7%, p<0.001). In 93.1% (27/29) of the NMO cases, the axial section of the spinal MRI showed lesions on the central gray matter only, whilst the spinal lesions in MS were usually located in the peripheral white matter (72.7%, 16/22). The AQP4-IgG antibody was found to be associated with both linear and LESC lesions in NMO cases.

CONCLUSIONS

High frequency of linear lesions and LESC lesions were found in Chinese patients with NMO and linear lesions were correlated with AQP4-IgG antibody.

Hypercomplementemia at relapse in patients with anti-aquaporin-4 antibody

Objective

Because Asian patients with opticospinal multiple sclerosis (OSMS) frequently have anti-aquaporin-4 (AQP4) antibody, complement-mediated disruption of astrocyte foot processes is proposed but not yet proven. We aimed to clarify whether complement consumption occurs at relapse in anti-AQP4 antibody-positive patients.

Methods

We analyzed serum CH50, C3, C4, and C-reactive protein (CRP) levels and their relation to clinical phases in 118 MS patients with or without anti-AQP4 antibody. Serum CH50 levels were higher in 24 patients with anti-AQP4 antibody than in 39 OSMS and 54 conventional form of MS (CMS) patients without anti-AQP4 antibody at relapse ( Pcorr < 0.05) but not in remission. The frequency of hypercomplementemia at relapse was also higher in anti-AQP4 antibody-positive patients than in anti-AQP4 antibody-negative CMS patients (70.4% vs 29.0%, Pcorr < 0.05). C3 and C4 levels did not differ significantly among the three groups at relapse. In patients with anti-AQP4 antibody, the coexistence of hypercomplementemia and high CRP values was more common at relapse than in the remission phase (36.0% vs 10.5%, P < 0.05). In patients with extensive central nervous system lesions, hypercomplementemia was significantly more common in anti-AQP4 antibody-positive patients than anti-AQP4 antibody-negative ones (88.9% vs 16.7%, P < 0.01). We consider that hypercomplementemia in anti-AQP4 antibody-positive patients may reflect a systemic inflammatory reaction at relapse.

Neuromyelitis optica and asian phenotype of multiple sclerosis

Multiple sclerosis (MS) is a demyelinating disease of the central nervous system (CNS), whereas neuromyelitis optica (NMO) is an inflammatory disease of the CNS selectively affecting the optic nerves and spinal cord. The pathological hallmark in MS is sharply demarcated demyelinating plaque with axons relatively preserved, whereas in NMO both axons and myelin are involved, resulting in necrotic cavitation. The nosological position of NMO has long been a matter of debate. In Asians, MS is rare; however, when it appears, the selective but severe involvement of the optic nerves and spinal cord is characteristic. This form, termed opticospinal MS (OSMS), has similar features to those of the relapsing form of NMO in Western populations. Recent discovery of a specific immunoglobulin G (IgG) against NMO, designated NMO-IgG, suggests that NMO is a distinct disease entity with a fundamentally different etiology from that of MS. Because NMO-IgG has been reported to be present in about 50%-60% of OSMS patients with longitudinally extensive spinal cord lesions (LESCLs), OSMS in Asians has been suggested to be the same entity as NMO. About half of the patients with the anti-aquaporin 4 (AQP4) antibody demonstrate brain lesions fulfilling the Barkhof criteria, whereas OSMS patients without the anti-AQP4 antibody show significantly fewer brain lesions. These findings indicate that the mechanism of LESCLs in Asians is heterogeneous, both related and unrelated to anti-AQP4 antibody, and that the disease condition with anti-AQP4 antibody does not completely overlap OSMS in Asians. This review discusses possible mechanisms for OSMS and anti-AQP4 autoimmune syndrome of the CNS.