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Measures of step variability and body sway during gait have shown to correlate with clinical ataxia severity in several cross-sectional studies. However, to serve as a valid progression biomarker, these gait measures have to prove their sensitivity to robustly capture longitudinal change, ideally within short time frames (eg, 1 year). We present the first multicenter longitudinal gait analysis study in spinocerebellar ataxias. We performed a combined cross-sectional (n = 28) and longitudinal (1-year interval, n = 17) analysis in Spinocerebellar Ataxia type 3 subjects (including seven preataxic mutation carriers). Longitudinal analysis showed significant change in gait measures between baseline and 1-year follow-up, with high effect sizes (stride length variability: P = 0.01, effect size r prb  = 0.66; lateral sway: P = 0.007, r prb  = 0.73). Sample size estimation for lateral sway indicates a required cohort size of n = 43 for detecting a 50% reduction of natural progression, compared with n = 240 for the clinical ataxia score Scale for the Assessment and Rating of Ataxia (SARA). These measures thus present promising motor biomarkers for upcoming interventional studies. © 2022 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society., (© 2022 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.)

Background: Rivastigmine is an acetylcholine esterase inhibitor which is commonly used as therapy for dementia in Alzheimer's disease and Parkinson's disease (PD). Recently, a randomized controlled trial demonstrated a positive effect of rivastigmine on gait function in nondemented PD patients. Disturbed gait is a shared hallmark of PD and ataxias., Objectives: We hypothesized that the effect of rivastigmine could be translated to spinocerebellar ataxia (SCA) improving gait function., Method: Five patients with SCA type 3 were treated with transdermal rivastigmine for 8 weeks. The patients were monitored using the Scale for the Assessment and Rating of Ataxia (SARA) and an electronic walkway system (GAITRite®)., Results: Gait function was not changed by treatment, but 4 patients who continued treatment for 8 weeks showed improved coordination of extremities. The SARA sum score, which was 7.6 ± 2.2 at baseline, had dropped by 1.5 ± 1.9 after 4 weeks and by 2.1 ± 1.4 after 8 weeks., Conclusions: Contrary to our hypothesis, we observed no improvement of gait parameters as assessed by SARA and GAIT-Rite®, but coordination abilities were improved. Rivastigmine was well tolerated, but known side effects of rivastigmine, such as deterioration of asthma, may appear. Further trials in larger cohorts are needed to confirm our findings., (© 2020 S. Karger AG, Basel.)

Spinocerebellar ataxia type 3 (SCA3) is a polyglutamine disorder caused by a CAG repeat expansion in the coding region of a gene encoding ataxin-3. To study putative alterations of gene expression induced by expanded ataxin-3, we performed PCR-based cDNA subtractive hybridization in a cell culture model of SCA3. In rat mesencephalic CSM14.1 cells stably expressing expanded ataxin-3, we found a significant upregulation of mRNAs encoding the endopeptidase matrix metalloproteinase 2 (MMP-2), the transmembrane protein amyloid precursor protein, the interleukin-1 receptor-related Fos-inducible transcript, and the cytokine stromal cell-derived factor 1alpha (SDF1alpha). Immunohistochemical studies of the corresponding or associated proteins in human SCA3 brain tissue confirmed these findings, showing increased expression of MMP-2 and amyloid beta-protein (Abeta) in pontine neurons containing nuclear inclusions. In addition, extracellular Abeta-immunoreactive deposits were detected in human SCA3 pons. Furthermore, pontine neurons of SCA3 brains strongly expressed the antiinflammatory interleukin-1 receptor antagonist, the proinflammatory cytokine interleukin-1beta, and the proinflammatory chemokine SDF1. Finally, increased numbers of reactive astrocytes and activated microglial cells were found in SCA3 pons. These results suggest that inflammatory processes are involved in the pathogenesis of SCA3.