Secondary Progressive Multiple Sclerosis: A Review of Clinical Characteristics, Definition, Prognostic Tools, and Disease-Modifying Therapies.

Many challenges exist in the precise diagnosis and clinical management of secondary progressive multiple sclerosis (SPMS) because of the lack of definitive clinical, imaging, immunologic, or pathologic criteria that demarcate the transition from relapsing-remitting MS to SPMS. This review provides an overview of the diagnostic criteria/definition and the heterogeneity associated with different SPMS patient populations; it also emphasizes the importance of available prospective/retrospective tools to identify patients with SPMS earlier in the disease course so that approved disease-modifying therapies and nonpharmacological strategies will translate into better outcomes. Delivery of such interventions necessitates an evolving patient-clinician dialog within the context of a multidisciplinary team.

Assessing the immune response to SARS-CoV-2 mRNA vaccines in siponimod-treated patients: a nonrandomized controlled clinical trial (AMA-VACC).

Background: Systematic data are lacking on the immune response toward SARS-CoV-2 mRNA vaccination in SPMS patients on disease-modifying therapies (DMTs). Objective: The AMA-VACC clinical trial was designed to characterize immune responses to SARS-CoV-2 mRNA vaccines in siponimod-treated SPMS patients. Design: AMA-VACC is an ongoing three-cohort, multicenter, open-label, prospective clinical study. Methods: The study included patients at risk for SPMS or patients with SPMS diagnosis. Patients received SARS-CoV-2 mRNA vaccine as part of their clinical routine during ongoing siponimod treatment (cohort 1), during siponimod treatment interruption (cohort 2), or while on dimethyl fumarate, glatiramer acetate, beta-interferons, teriflunomide, or no current therapy (cohort 3). SARS-CoV-2-specific neutralizing antibodies and T-cell responses were measured 1 week and 1 month after the second dose of vaccination. Results: In total, 17 patients, 4 patients, and 20 patients were recruited into cohorts 1, 2, and 3, respectively. The primary endpoint of seroconversion for SARS-CoV-2-neutralizing antibodies at week 1 was reached by 52.9%, 75.0%, and 90.0% of patients in cohorts 1, 2, and 3, respectively. For 64.7% of patients in cohort 1, all patients in cohort 2, and 95% of patients in cohort 3, seroconversion was observed at either week 1 or month 1 or both time points. After 1 week, 71.4% of cohort 1, 75.0% of cohort 2, and 85.0% of cohort 3 were positive for either SARS-CoV-2-neutralizing antibodies or SARS-CoV-2-specific T-cells or both. After 1 month, the rates were 56.3%, 100.0%, and 95.0%, respectively. Conclusion: The study shows that the majority of siponimod patients mount humoral and cellular immune response under continuous siponimod treatment. The data do not sufficiently support interruption of treatment for the purpose of vaccination. Registration: EU Clinical Trials Register: EudraCT 2020-005752-38 (www.clinicaltrialsregister.eu); ClinicalTrials.gov: NCT04792567 (https://clinicaltrials.gov).

Parkinson's disease motor symptoms rescue by CRISPRa-reprogramming astrocytes into GABAergic neurons.

Direct reprogramming based on genetic factors resembles a promising strategy to replace lost cells in degenerative diseases such as Parkinson's disease. For this, we developed a knock-in mouse line carrying a dual dCas9 transactivator system (dCAM) allowing the conditional in vivo activation of endogenous genes. To enable a translational application, we additionally established an AAV-based strategy carrying intein-split-dCas9 in combination with activators (AAV-dCAS). Both approaches were successful in reprogramming striatal astrocytes into induced GABAergic neurons confirmed by single-cell transcriptome analysis of reprogrammed neurons in vivo. These GABAergic neurons functionally integrate into striatal circuits, alleviating voluntary motor behavior aspects in a 6-OHDA Parkinson's disease model. Our results suggest a novel intervention strategy beyond the restoration of dopamine levels. Thus, the AAV-dCAS approach might enable an alternative route for clinical therapies of Parkinson's disease.

Characteristics of secondary progressive multiple sclerosis: Disease activity and provision of care in Germany - A registry-based/multicentric cohort study.

BACKGROUND: The tailored immunomodulatory treatment strategy for secondary progressive multiple sclerosis (SPMS) depends on disease activity. OBJECTIVE: To assess the real-world situation in monitoring disease activity in SPMS patients and to identify associations of resulting subgroups with demographics, symptomatology, and therapy METHODS: This study included 4,263 SPMS patients from the German MS register (GMSR). For the classification into 'active' and 'inactive' according to relapse activity and MRI findings during the year prior to the latest clinical visit, we used the following definitions: active - gadolinium enhancing (Gd+)/new T2 lesions or ≥1 relapse, inactive - neither Gd+/new T2 lesions nor relapses. The active, inactive, and unclassifiable patients were compared in terms of clinical data, socio-demographics, symptomatology, healthcare, and DMT. RESULTS: Classification was possible for 1,513 (35.5%) SPMS patients, with 467 classified as active and 1,046 as inactive. For the classification, MRI data was available for 33.2% of the 4,263 patients. Higher MRI frequencies were observed for younger patients (OR 1.22 [1.12,1.33] per 10 years) with short disease duration (OR 1.19 [1.09, 1.30] per 10 years) (p < 0.001). CONCLUSION: MRI coverage was low, especially in elderly SPMS patients. Roughly one third of the SPMS patients presented markers of disease activity in the last year. Overall, the clinical differences (concerning symptomatology and care) between patients with active and inactive SPMS were small.

Multiple Sclerosis Progression Discussion Tool Usability and Usefulness in Clinical Practice: Cross-sectional, Web-Based Survey.

BACKGROUND: A digital tool, Multiple Sclerosis Progression Discussion Tool (MSProDiscuss), was developed to facilitate discussions between health care professionals (HCPs) and patients in evaluating early, subtle signs of multiple sclerosis (MS) disease progression. OBJECTIVE: The aim of this study is to report the findings on the usability and usefulness of MSProDiscuss in a real-world clinical setting. METHODS: In this cross-sectional, web-based survey, HCPs across 34 countries completed an initial individual questionnaire (comprising 7 questions on comprehensibility, usability, and usefulness after using MSProDiscuss during each patient consultation) and a final questionnaire (comprising 13 questions on comprehensibility, usability, usefulness, and integration and adoption into clinical practice to capture the HCPs' overall experience of using the tool). The responses were provided on a 5-point Likert scale. All analyses were descriptive, and no statistical comparisons were made. RESULTS: In total, 301 HCPs tested the tool in 6974 people with MS, of whom 77% (5370/6974) had relapsing-remitting MS, including those suspected to be transitioning to secondary progressive MS. The time taken to complete MSProDiscuss was reported to be in the range of 1 to 4 minutes in 97.3% (6786/6974; initial) to 98.2% (269/274; final) of the cases. In 93.54% (6524/6974; initial) to 97.1% (266/274; final) of the cases, the HCPs agreed (4 or 5 on the Likert scale) that patients were able to comprehend the questions in the tool. The HCPs were willing to use the tool again in the same patient, 90.47% (6310/6974; initial) of the cases. The HCPs reported MSProDiscuss to be useful in discussing MS symptoms and their impact on daily activities (6121/6974, 87.76% initial and 252/274, 92% final) and cognitive function (5482/6974, 78.61% initial and 271/274, 79.2% final), as well as in discussing progression in general (6102/6974, 87.49% initial and 246/274, 89.8% final). While completing the final questionnaire, 94.9% (260/274) of the HCPs agreed that the questions were similar to those asked in regular consultation, and the tool helped to better understand the impact of MS symptoms on daily activities (249/274, 90.9%) and cognitive function (220/274, 80.3%). Overall, 92% (252/274) of the HCPs reported that they would recommend MSProDiscuss to a colleague, and 85.8% (235/274) were willing to integrate it into their clinical practice. CONCLUSIONS: MSProDiscuss is a usable and useful tool to facilitate a physician-patient discussion on MS disease progression in daily clinical practice. Most of the HCPs agreed that the tool is easy to use and were willing to integrate MSProDiscuss into their daily clinical practice.

Dose-Dependent and Subset-Specific Regulation of Midbrain Dopaminergic Neuron Differentiation by LEF1-Mediated WNT1/b-Catenin Signaling.

The mesodiencephalic dopaminergic (mdDA) neurons, including the nigrostriatal subset that preferentially degenerates in Parkinson's Disease (PD), strongly depend on an accurately balanced Wingless-type MMTV integration site family member 1 (WNT1)/beta-catenin signaling pathway during their development. Loss of this pathway abolishes the generation of these neurons, whereas excessive WNT1/b-catenin signaling prevents their correct differentiation. The identity of the cells responding to this pathway in the developing mammalian ventral midbrain (VM) as well as the precise progression of WNT/b-catenin action in these cells are still unknown. We show that strong WNT/b-catenin signaling inhibits the differentiation of WNT/b-catenin-responding mdDA progenitors into PITX3+ and TH+ mdDA neurons by repressing the Pitx3 gene in mice. This effect is mediated by RSPO2, a WNT/b-catenin agonist, and lymphoid enhancer binding factor 1 (LEF1), an essential nuclear effector of the WNT/b-catenin pathway, via conserved LEF1/T-cell factor binding sites in the Pitx3 promoter. LEF1 expression is restricted to a caudolateral mdDA progenitor subset that preferentially responds to WNT/b-catenin signaling and gives rise to a fraction of all mdDA neurons. Our data indicate that an attenuation of WNT/b-catenin signaling in mdDA progenitors is essential for their correct differentiation into specific mdDA neuron subsets. This is an important consideration for stem cell-based regenerative therapies and in vitro models of neuropsychiatric diseases.

Gaining First Insights on Secondary Progressive Multiple Sclerosis Patients Treated With Siponimod in Clinical Routine: Protocol of the Noninterventional Study AMASIA.

BACKGROUND: A high proportion of patients with relapsing remitting multiple sclerosis convert to secondary progressive multiple sclerosis (SPMS) characterized by irreversibly progressing disability and cognitive decline. Siponimod (Mayzent), a selective sphingosine-1-phosphate receptor modulator, was recently approved by the European Medicines Agency for the treatment of adult SPMS patients with active disease, as evidenced by relapses or magnetic resonance imaging features of ongoing inflammatory activity. Approval by the Food and Drug Administration covers a broader range of indications, comprising clinically isolated syndrome, relapsing remitting multiple sclerosis, and active SPMS. However, treatment effects of siponimod have not been assessed in a structured setting in clinical routine so far. OBJECTIVE: The objectives of AMASIA (impAct of Mayzent [siponimod] on secondAry progressive multiple Sclerosis patients in a long-term non-Interventional study in GermAny), a prospective noninterventional study, are to assess the long-term effectiveness and safety of siponimod in clinical routine and to evaluate the impact of disease burden on quality of life and socioeconomic conditions. Here, we report the study design of AMASIA. METHODS: Treatment effects of siponimod will be evaluated in 1500 SPMS patients during a 3-year observational phase. According to the genetic polymorphism of CYP2C9, the initial dose will be titrated to the maintenance dose of 1 mg (CYP2C9*1*3 and *2*3) or 2 mg (all other polymorphisms of CYP2C9 except *3*3, which is contraindicated) taken orally once daily. Primary endpoint is the 6-month confirmed disability progression, as assessed by a functional composite endpoint comprising the Expanded Disability Status Scale and symbol digit modalities test to take appropriate account of cognitive changes and increase sensitivity. Further measures including multiple sclerosis activity data; assessments of functional domains; questionnaires addressing the patients', physicians', and relatives' perspectives of disability progression; cognitive worsening; quality of life; and socioeconomic aspects will be documented using the multiple sclerosis documentation system MSDS3D. RESULTS: AMASIA is being conducted between February 2020 and February 2025 in up to 250 neurological centers in Germany. CONCLUSIONS: AMASIA will complement the pivotal phase III-derived efficacy and safety profile of siponimod with real-world data and will further evaluate several individual treatment aspects such as quality of life and socioeconomic conditions of patients and caregivers. It might help to establish siponimod as a promising option for the treatment of SPMS patients in clinical routine. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/19598.

Dickkopf 3 Promotes the Differentiation of a Rostrolateral Midbrain Dopaminergic Neuronal Subset In Vivo and from Pluripotent Stem Cells In Vitro in the Mouse.

Wingless-related MMTV integration site 1 (WNT1)/ß-catenin signaling plays a crucial role in the generation of mesodiencephalic dopaminergic (mdDA) neurons, including the substantia nigra pars compacta (SNc) subpopulation that preferentially degenerates in Parkinson's disease (PD). However, the precise functions of WNT1/ß-catenin signaling in this context remain unknown. Stem cell-based regenerative (transplantation) therapies for PD have not been implemented widely in the clinical context, among other reasons because of the heterogeneity and incomplete differentiation of the transplanted cells. This might result in tumor formation and poor integration of the transplanted cells into the dopaminergic circuitry of the brain. Dickkopf 3 (DKK3) is a secreted glycoprotein implicated in the modulation of WNT/ß-catenin signaling. Using mutant mice, primary ventral midbrain cells, and pluripotent stem cells, we show that DKK3 is necessary and sufficient for the correct differentiation of a rostrolateral mdDA neuron subset. Dkk3 transcription in the murine ventral midbrain coincides with the onset of mdDA neurogenesis and is required for the activation and/or maintenance of LMX1A (LIM homeobox transcription factor 1α) and PITX3 (paired-like homeodomain transcription factor 3) expression in the corresponding mdDA precursor subset, without affecting the proliferation or specification of their progenitors. Notably, the treatment of differentiating pluripotent stem cells with recombinant DKK3 and WNT1 proteins also increases the proportion of mdDA neurons with molecular SNc DA cell characteristics in these cultures. The specific effects of DKK3 on the differentiation of rostrolateral mdDA neurons in the murine ventral midbrain, together with its known prosurvival and anti-tumorigenic properties, make it a good candidate for the improvement of regenerative and neuroprotective strategies in the treatment of PD. Significance statement: We show here that Dickkopf 3 (DKK3), a secreted modulator of WNT (Wingless-related MMTV integration site)/ß-catenin signaling, is both necessary and sufficient for the proper differentiation and survival of a rostrolateral (parabrachial pigmented nucleus and dorsomedial substantia nigra pars compacta) mesodiencephalic dopaminergic neuron subset, using Dkk3 mutant mice and murine primary ventral midbrain and pluripotent stem cells. The progressive loss of these dopamine-producing mesodiencephalic neurons is a hallmark of human Parkinson's disease, which can up to now not be halted by clinical treatments of this disease. Thus, the soluble DKK3 protein might be a promising new agent for the improvement of current protocols for the directed differentiation of pluripotent and multipotent stem cells into mesodiencephalic dopaminergic neurons and for the promotion of their survival in situ.

Limitations of In Vivo Reprogramming to Dopaminergic Neurons via a Tricistronic Strategy.

Parkinson's disease is one of the most common neurodegenerative disorders characterized by cell death of dopaminergic neurons in the substantia nigra. Recent research has focused on cellular replacement through lineage reprogramming as a potential therapeutic strategy. This study sought to use genetics to define somatic cell types in vivo amenable to reprogramming. To stimulate in vivo reprogramming to dopaminergic neurons, we generated a Rosa26 knock-in mouse line conditionally overexpressing Mash1, Lmx1a, and Nurr1. These proteins are characterized by their role in neuronal commitment and development of midbrain dopaminergic neurons and have previously been shown to convert fibroblasts to dopaminergic neurons in vitro. We show that a tricistronic construct containing these transcription factors can reprogram astrocytes and fibroblasts in vitro. However, cassette overexpression triggered cell death in vivo, in part through endoplasmic reticulum stress, while we also detected "uncleaved" forms of the polyprotein, suggesting poor "cleavage" efficiency of the 2A peptides. Based on our results, the cassette overexpression induced apoptosis and precluded reprogramming in our mouse model. Therefore, we suggest that alternatives must be explored to balance construct design with efficacious reprogramming. It is evident that there are still biological obstacles to overcome for in vivo reprogramming to dopaminergic neurons.