The natural history of primary progressive multiple sclerosis: insights from the German NeuroTransData registry.

BACKGROUND: Primary progressive multiple sclerosis (PPMS) is characterised by gradual worsening of disability from symptom onset. Knowledge about the natural course of PPMS remains limited. METHODS: PPMS patients from the German NeuroTransData (NTD) MS registry with data from 56 outpatient practices were employed for retrospective cross-sectional and longitudinal analyses. The cross-sectional analysis included a contemporary PPMS cohort with a documented visit within the last 2 years before index date (1 Jan 2021). The longitudinal analysis included a disease modifying therapy (DMT)-naïve population and focused on the evolution of expanded disability status scale (EDSS) from the first available assessment at or after diagnosis within the NTD registry to index date. Outcome measures were estimated median time from first EDSS assessment to first 24-week confirmed EDSS ≥ 4 and ≥ 7. Besides EDSS change, the proportion of patients on disability pension were described over time. RESULTS: The cross-sectional analysis included 481 PPMS patients (59.9% female, mean [standard deviation, SD] age 60.5 [11.5] years, mean [SD] EDSS 4.9 [2.1]). Estimated median time from first EDSS assessment after diagnosis to reach 24-week confirmed EDSS ≥ 4 for DMT-naïve patients was 6.9 years. Median time to EDSS ≥ 7 was 9.7 years for 25% of the population. Over a decade mean (SD) EDSS scores increased from 4.6 (2.1) to 5.7 (2.0); the proportion of patients on disability pension increased from 18.9% to 33.3%. CONCLUSIONS: This study provides first insights into the German NTD real-world cohort of PPMS patients. Findings confirm the steadily deteriorating course of PPMS accompanied by increasingly limited quality of life.

Safety, Adherence and Persistence in a Real-World Cohort of German MS Patients Newly Treated With Ocrelizumab: First Insights From the CONFIDENCE Study.

Background: Real-world relapsing multiple sclerosis (RMS) and primary progressive MS (PPMS) populations may be more diverse than in clinical trials. Here, we present a first analysis of safety, adherence and persistence data from a real-world cohort of patients newly treated with ocrelizumab. Methods: CONFIDENCE (ML39632, EUPAS22951) is an ongoing multicenter, non-interventional post authorization safety study assessing patients with RMS or PPMS newly treated with ocrelizumab or other disease-modifying therapies for up to 10 years. For this analysis, patients newly treated with ocrelizumab were analyzed in subgroups by MS phenotype and age over a mean ~1 year of exposure totaling 2,329 patient years [PY]). Results: At data cutoff (14 October 2020), 1,702 patients with RMS and 398 patients with PPMS were treated with ≥1 dose of ocrelizumab. At baseline, the mean ages (SD) of patients with RMS and PPMS were 41.59 (11.24) and 50.95 (9.88) years and the mean EDSS (Expanded Disability Status Scale) was 3.18 (1.87) and 4.41 (1.59), respectively. The most common adverse events (AEs) and serious AEs across both phenotypes were infections and infestations, with infection SAE rates of 2.8 events/100 PY and 1.5 events/100 PY in patients with RMS and PPMS, respectively. Across all phenotypes, ocrelizumab persistence was 92% at 24 months; median time between doses was ~6 months. Conclusions: The ocrelizumab safety profile observed in the CONFIDENCE real-world MS population was consistent to the one observed in pivotal clinical trials. High treatment persistence and adherence were observed. Trial Registration: ML39632, EUPAS22951.

Design of a non-interventional post-marketing study to assess the long-term safety and effectiveness of ocrelizumab in German real world multiple sclerosis cohorts - the CONFIDENCE study protocol.

BACKGROUND: Multiple sclerosis (MS) is a chronic disease that requires lifelong treatment. A highly effective drug not only for relapsing but also for progressive forms of MS with a favorable safety profile is needed to further improve overall patient outcomes. Ocrelizumab, a recombinant humanized monoclonal antibody that selectively targets CD20-expressing B-cells, is the first drug indicated for the treatment of adult patients with relapsing forms of MS (RMS) and primary progressive MS (PPMS). Its safety and effectiveness profile has yet to be studied in a large, real-world setting. CONFIDENCE aims to further characterize the safety profile of ocrelizumab in routine clinical practice. In addition, real-world effectiveness data will be collected to complement the efficacy data documented in the pivotal clinical trials. METHODS: CONFIDENCE is a non-interventional, prospective, multicenter, long-term study collecting primary data from 3000 RMS and PPMS patients newly treated with ocrelizumab and 1500 patients newly treated with other selected MS disease-modifying therapies (DMTs). Treatment must be in accordance with the local label and follow routine practice. Data will be collected at approximately 250 neurological centers and practices across Germany. The recruitment period of 30 months started in April 2018. The observation period per patient is planned 7.5 to 10 years, depending on the date of inclusion, regardless of whether patients discontinue treatment. Visits follow routine practice and will be documented approximately every 6 months. The primary endpoint is the incidence and type of uncommon adverse events and death. Statistical analyses will be mainly descriptive and exploratory. DISCUSSION: CONFIDENCE is a large, non-interventional, post-authorization safety study that assesses long-term safety and effectiveness of ocrelizumab and other DMTs in a real-world setting. Data collected in CONFIDENCE will also be integrated into studies that have been developed to fulfil international regulatory requirements.

Connexin57 is expressed in dendro-dendritic and axo-axonal gap junctions of mouse horizontal cells and its distribution is modulated by light.

Mouse horizontal cells are coupled by gap junctions composed of connexin57. These gap junctions are regulated by ambient light via multiple neuromodulators including dopamine. In order to analyze the distribution and structure of horizontal cell gap junctions in the mouse retina, and examine the effects of light adaptation on gap junction density, we developed antibodies that detect mouse retinal connexin57. Using immunohistochemistry in retinal slices, flat-mounted retinas, and dissociated retinal cells, we showed that connexin57 is expressed in the dendrites and axon terminal processes of mouse horizontal cells. No staining was found in retinas of connexin57-deficient mice. Significantly more connexin57-positive puncta were found in the distal than in the proximal outer plexiform layer, indicating a higher level of expression in axon terminal processes than in the dendrites. We also examined the gap junctions using immunoelectron microscopy and showed that connexin57 does not form hemichannels in the horizontal cell dendritic tips. Light adaptation resulted in a significant increase in the number of connexin57-immunoreactive plaques in the outer plexiform layer, consistent with previously reported effects of light adaptation on connexin57 expression in the mouse retina. This study shows for the first time the detailed location of connexin57 expression within mouse horizontal cells, and provides the first ultrastructural data on mouse horizontal cell gap junctions.

Ether-à-gogo-related gene (erg1) potassium channels shape the dark response of horizontal cells in the mammalian retina.

Postsynaptic to photoreceptors, horizontal cells face prolonged exposure to glutamate in the dark. Therefore, efficient hyperpolarizing mechanisms are crucial to keep horizontal cells within an operating range and to reduce glutamate-induced excitotoxicity. Combining electrophysiology, single-cell reverse transcriptase polymerase chain reaction, and immunocytochemistry, we found that horizontal cell bodies but not their axon terminals express the ether-à-gogo-related gene isoform 1 (erg1) K(+) channel. Erg1-mediated outward currents displayed voltage-dependent activation and C-type inactivation. Recovery from inactivation involved a transient open state. Gating of erg1 channels kept the voltage response to glutamate brief and at physiological amplitudes. With erg1 channels blocked, the response of horizontal cells to the onset of darkness was significantly enhanced. These results indicate a functional dichotomy between horizontal cell bodies and axon terminals in the processing of photoreceptor signals. The dark response thus reflects a finely tuned balance determined by the successive gating of ionotropic glutamate receptors and erg1 channels.

Localization of heterotypic gap junctions composed of connexin45 and connexin36 in the rod pathway of the mouse retina.

The primary rod pathway in mammals contains gap junctions between AII amacrine cells and ON cone bipolar cells which relay the rod signal into the cone pathway under scotopic conditions. Two gap junctional proteins, connexin36 (Cx36) and connexin45 (Cx45), appear to play a pivotal role in this pathway because lack of either protein leads to an impairment of visual transmission under scotopic conditions. To investigate whether these connexins form heterotypic gap junctions between ON cone bipolar and AII amacrine cells, we used newly developed Cx45 antibodies and studied the cellular and subcellular distribution of this protein in the mouse retina. Specificity of the Cx45 antibodies was determined, among others, by Western blot and immunostaining of mouse heart, where Cx45 is abundantly expressed. In mouse retina, Cx45 immunosignals were detected in both plexiform layers and the ganglion cell layer. Double staining for Cx45 and Cx36 revealed a partial overlap in the punctate patterns in the ON sublamina of the inner plexiform layer of the retina. We quantified the distributions of these two connexins in the ON sublamina, and detected 30% of the Cx45 signals to be co-localized with or in close apposition to Cx36 signals. Combining immunostaining and intracellular dye injection revealed an overlap or tight association of Cx36 and Cx45 signals on the terminals of injected AII amacrine and two types of ON cone bipolar cells. Our results provide direct evidence for heterotypic gap junctions composed of Cx36 and Cx45 between AII amacrine and certain types of ON cone bipolar cells.

The cytoplasmic domain of NrCAM binds to PDZ domains of synapse-associated proteins SAP90/PSD95 and SAP97.

NrCAM, a member of the L1 family of cell adhesion molecules, serves important functions during the development of the nervous system, e.g. in adhesion-dependent processes such as neurite outgrowth and axonal pathfinding. Complex homo- and heterophilic binding and several extracellular ligands of NrCAM have been described, but less is known about intracellular interaction partners. The cytoplasmic carboxy-terminus of NrCAM contains a typical sequence motif for binding to PDZ domains, making interactions with PDZ domain-containing scaffolding proteins quite conceivable. In this study, we identified specific interactions of the intracellular domain of NrCAM with class I PDZ domains of the membrane-associated guanylate kinases SAP90/PSD95 and SAP97. In contrast to NrCAM, the intracellular domains of the other mammalian L1 family molecules, e.g. L1, CHL1 and Neurofascin, did not interact with these PDZ domains. In transfected COS-7 cells, NrCAM-mediated recruitment of SAP97 to the plasma membrane was dependent on the PDZ binding motif. We show that NrCAM and SAP97 are colocalized, e.g. within photoreceptor terminals of the mammalian retina. In summary, our results confirm a functional PDZ domain binding motif at the carboxy-terminus of NrCAM and support potential functions of NrCAM during the assembly of highly organized protein complexes at the cell membrane.

Characterization of retinoic acid neuromodulation in the carp retina.

Visual sensation in vertebrates starts with the isomerization of 11-cis retinaldehyde into all-trans retinaldehyde. Aldehyde dehydrogenases, present in the pigment epithelium and some retinal cells, convert all-trans retinaldehyde into all-trans retinoic acid (at-RA). Evidence in the retina and the hippocampus has accumulated, showing that at-RA, besides being a morphogenetic factor, also acts as a neuromodulator. In mature retina, at-RA affects visual processing by acting on gap junctional conductances and the synaptic transfer between photoreceptors and horizontal cells. We present evidence supporting a neuromodulatory role of at-RA in the carp retina. High performance liquid chromatography (HPLC) measurements and an RA bioassay indicate a light dependency of at-RA formation, which can explain the observed effects of at-RA on spinule formation at horizontal cell dendrites in this retina. Furthermore, inhibiting endogenous metabolism and catabolism of at-RA affects formation and persistence of spinules in a way, supporting a direct involvement of at-RA in this light-dependent mechanism of synaptic plasticity. The action of at-RA, however, seems independent of the dopaminergic system, known for its light-signaling role in the retina, because at-RA effects on spinule formation persisted in retina depleted of dopaminergic neurons or in the presence of haloperidol. Together, these data indicate that at-RA acts effectively as a direct neuromodulator in carp retina, transmitting information about ambient light conditions to the neuronal retina.

Cryptochromes and neuronal-activity markers colocalize in the retina of migratory birds during magnetic orientation.

Migratory birds can use a magnetic compass for orientation during their migratory journeys covering thousands of kilometers. But how do they sense the reference direction provided by the Earth's magnetic field? Behavioral evidence and theoretical considerations have suggested that radical-pair processes in differently oriented, light-sensitive molecules of the retina could enable migratory birds to perceive the magnetic field as visual patterns. The cryptochromes (CRYs) have been suggested as the most likely candidate class of molecules, but do CRYs exist in the retina of migratory birds? Here, we show that at least one CRY1 and one CRY2 exist in the retina of migratory garden warblers and that garden-warbler CRY1 (gwCRY1) is cytosolic. We also show that gwCRY1 is concentrated in specific cells, particularly in ganglion cells and in large displaced ganglion cells, which also showed high levels of neuronal activity at night, when our garden warblers performed magnetic orientation. In addition, there seem to be striking differences in CRY1 expression between migratory and nonmigratory songbirds at night. The difference in CRY1 expression between migrants and nonmigrants is particularly pronounced in the large displaced ganglion cells known to project exclusively to a brain area where magnetically sensitive neurons have been reported. Consequently, cytosolic gwCRY1 is well placed to possibly be the primary magnetic-sensory molecule required for light-mediated magnetoreception.