Robust model-based analysis of single-particle tracking experiments with Spot-On.

Single-particle tracking (SPT) has become an important method to bridge biochemistry and cell biology since it allows direct observation of protein binding and diffusion dynamics in live cells. However, accurately inferring information from SPT studies is challenging due to biases in both data analysis and experimental design. To address analysis bias, we introduce 'Spot-On', an intuitive web-interface. Spot-On implements a kinetic modeling framework that accounts for known biases, including molecules moving out-of-focus, and robustly infers diffusion constants and subpopulations from pooled single-molecule trajectories. To minimize inherent experimental biases, we implement and validate stroboscopic photo-activation SPT (spaSPT), which minimizes motion-blur bias and tracking errors. We validate Spot-On using experimentally realistic simulations and show that Spot-On outperforms other methods. We then apply Spot-On to spaSPT data from live mammalian cells spanning a wide range of nuclear dynamics and demonstrate that Spot-On consistently and robustly infers subpopulation fractions and diffusion constants

Retrograde procedural memory is impaired in people with Parkinson’s disease with freezing of gait

BackgroundFreezing of gait (FOG), is associated with impairment of different cognitive functions. Previous studies hypothesized that FOG may be due to a loss of automaticity.Research questionTo explore whether FOG is associated with impairment in cognitive functions, focusing on retrograde procedural memory, the memory responsible for the automatic, implicit stored procedures that have been acquired in earlier life stages.MethodsIn this cross-sectional, case–control study, 288 people with typical Parkinson’s disease (PD) from the Luxembourg Parkinson’s Study were assigned to Freezers (FOG+) and non-Freezers (FOG−) based on the MDS-UPDRS 2.13 (self-reported FOG episodes) and 3.11 (FOG evaluated by clinicians during gait assessment). Both groups were matched on age, sex and disease duration. Global cognition (MoCA), retrograde procedural memory and visuo-constructive abilities (CUPRO), psychomotor speed and mental flexibility (TMT) were assessed. Furthermore, we repeated our analyses by additionally controlling for depression (BDI-I).ResultsBesides lower global cognition (MoCA; p = 0.007) and mental flexibility (TMT-B and Delta-TMT; p < 0.001), FOG+ showed a lower performance in retrograde procedural memory (CUPRO-IS1; p < 0.001) compared to FOG−. After controlling additionally for depression, our main outcome variable CUPRO-IS1 remained significantly lower in FOG+ (p = 0.010).ConclusionOur findings demonstrated that besides lower global cognition and mental flexibility scores, FOG+ showed lower performance in retrograde procedural memory compared to matched FOG-control patients, even when accounting for factors such as age, sex, disease duration or depression.SignificanceIn the context of limited treatment options, especially for non-invasive therapeutic approaches, these insights on procedural memory and FOG may lead to new hypotheses on FOG etiology and consequently the development of new treatment options

Epithelial label-retaining cells are absent during tooth cycling in Salmo salar and Polypterus senegalus

The Atlantic salmon (Salmo salar) and African bichir (Polypterus senegalus) are both actinopterygian fish species that continuously replace their teeth without the involvement of a successional dental lamina. Instead, they share the presence of a middle dental epithelium: an epithelial tier enclosed by inner and outer dental epithelium. It has been hypothesized that this tier could functionally substitute for a successional dental lamina and might be a potential niche to house epithelial stem cells involved in tooth cycling. Therefore, in this study we performed a BrdU pulse chase experiment on both species to (1) determine the localization and extent of proliferating cells in the dental epithelial layers, (2) describe cell dynamics and (3) investigate if label-retaining cells are present, suggestive for the putative presence of stem cells. Cells proliferate in the middle dental epithelium, outer dental epithelium and cervical loop at the lingual side of the dental organ to form a new tooth germ. Using long chase times, both in S. salar (eight weeks) and P. senegalus (eight weeks and twelve weeks), we could not reveal the presence of label-retaining cells in the dental organ. Immunostaining of P. senegalus dental organs for the transcription factor Sox2, often used as a stem cell marker, labelled cells in the zone of outer dental epithelium which grades into the oral epithelium (ODE transition zone) and the inner dental epithelium of a successor only. The location of Sox2 distribution does not provide evidence for epithelial stem cells in the dental organ and, more specifically, in the middle dental epithelium. Comparison of S. salar and P. senegalus reveals shared traits in tooth cycling and thus advances our understanding of the developmental mechanism that ensures lifelong replacement

Retrograde procedural memory is impaired in people with Parkinson’s disease with freezing of gait

peer reviewedFreezing of gait (FOG), is associated with impairment of different cognitive functions. Previous studies hypothesized that FOG may be due to a loss of automaticity. Research question: To explore whether FOG is associated with impairment in cognitive functions, focusing on retrograde procedural memory, the memory responsible for the automatic, implicit stored procedures that have been acquired in earlier life stages. Methods: In this cross-sectional, case–control study, 288 people with typical Parkinson’s disease (PD) from the Luxembourg Parkinson’s Study were assigned to Freezers (FOG+) and non-Freezers (FOG−) based on the MDS-UPDRS 2.13 (self-reported FOG episodes) and 3.11 (FOG evaluated by clinicians during gait assessment). Both groups were matched on age, sex and disease duration. Global cognition (MoCA), retrograde procedural memory and visuo-constructive abilities (CUPRO), psychomotor speed and mental flexibility (TMT) were assessed. Furthermore, we repeated our analyses by additionally controlling for depression (BDI-I). Results: Besides lower global cognition (MoCA; p = 0.007) and mental flexibility (TMT-B and Delta-TMT; p < 0.001), FOG+ showed a lower performance in retrograde procedural memory (CUPRO-IS1; p < 0.001) compared to FOG−. After controlling additionally for depression, our main outcome variable CUPRO-IS1 remained significantly lower in FOG+ (p = 0.010). Conclusion: Our findings demonstrated that besides lower global cognition and mental flexibility scores, FOG+ showed lower performance in retrograde procedural memory compared to matched FOG-control patients, even when accounting for factors such as age, sex, disease duration or depression. Significance: In the context of limited treatment options, especially for non-invasive therapeutic approaches, these insights on procedural memory and FOG may lead to new hypotheses on FOG etiology and consequently the development of new treatment options.3. Good health and well-bein

MORE SMOKE THAN FIRE NO SPEEDING UP OF PARKINSON‘S DISEASE AFTER COVID-10 LOCKDOWN

peer reviewedBackground and objectives As the influence of stress syndromes on the evolution of Parkinson’s disease (PD) remains largely unexplored, the COVID-19 pandemic offers the opportunity to evaluate the stress impact of the COVID-19 pandemic on PD trajectories. Methods This longitudinal observational case-control study used data from the Luxembourg Parkinson’s Study (1). A pandemic PD group with exposure to the restrictions imposed by the COVID-19 pandemic but without COVID-19 infection (n=79) was compared to a prepandemic PD control group (n= 117) that has never been exposed to any pandemic restrictions. All patients underwent three annual visits. The last analyzed in-person visit of the pandemic group occurred during the early pandemic phase, between September 2020 and March 2021. Motor and cognitive status were established through standardized in-person exams. Patients of the PD pandemic group selfrated their resilience and risk for posttraumatic stress disorder (PTSD) and, at visit 2 and 3, underwent the Olink panel of 92 serological inflammation markers. The primary outcome was motor PD progression as rated by the MDS-UPDRS part III score. The secondary outcomes were other progression scores (MDS-UPDRS I and II), cognitive performance (Montreal Cognitive Assessment), symptoms of depression (Beck Depression Inventory), risk for PTSD (revised Impact of Event Scale) and resilience (Brief Resilience Scale). Measures tested for statistical associations with these outcomes include demographic, lifestyle data and serological inflammation markers. To assess variable associations and correct effects from confounding factors, we used a multiple linear regression approach. Results The deterioration of the motor and cognitive scores from visit 1 to visit 3 was not different in the pandemic group compared to the prepandemic group. 74.7 % of the pandemic PD patients had normal or high resilience scores, whereas 20.3% were at risk of developing PTSD. Resilience was neither correlated with motor scores nor with cognitive scores but was negatively associated with depressive symptomatology and posttraumatic stress. Except for Axin-1, there was no increase in the inflammation markers at visit 3 compared to visit 2. Discussion This case-control study shows that there was no influence by the pandemic-induced stress on the natural progression of PD motor and cognitive trajectories.R-AGR-0592 - FNR - NCER-PD Phase II Coordination (01/06/2015 - 30/11/2023) - KRÜGER Rejko3. Good health and well-bein

Clinical, radiographic and immunogenic effects after 1 year of tocilizumab-based treatment strategies in rheumatoid arthritis: the ACT-RAY study

Objective: To assess the 1-year efficacy and safety of a regimen of tocilizumab plus methotrexate or placebo, which was augmented by a treat-to-target strategy from week 24. Methods: ACT-RAY was a double-blind, 3-year trial. Adults with active rheumatoid arthritis despite methotrexate were randomised to add tocilizumab to ongoing methotrexate (add-on strategy) or to switch to tocilizumab plus placebo (switch strategy). Tocilizumab 8 mg/kg was administered every 4 weeks. Conventional open-label disease-modifying antirheumatic drugs (DMARDs) other than methotrexate were added at week 24 or later in patients with DAS28>3.2. Results: 556 patients were randomised; 85% completed 52 weeks. The proportion of patients receiving open-label DMARDs was comparable in the add-on (29%) and switch (33%) arms. Overall, week 24 results were maintained or further improved at week 52 in both arms. Some endpoints favoured the add-on strategy. Mean changes in Genant-modified Sharp scores were small; more add-on (92.8%) than switch patients (86.1%) had no radiographic progression. At week 52, comparable numbers of patients had antidrug antibodies (ADAs; 1.5% and 2.2% of add-on and switch patients, respectively) and neutralising ADAs (0.7% and 1.8%). Rates of serious adverse events and serious infections per 100 patient-year (PY) were 11.3 and 4.5 in add-on and 16.8 and 5.5 in switch patients. In patients with normal baseline values, alanine aminotransferase elevations >3× upper limit of normal were observed in 11% of add-on and 3% of switch patients. Conclusions: Despite a trend favouring the add-on strategy, these data suggest that both tocilizumab add-on and switch strategies led to meaningful clinical and radiographic responses

Advancing patient-centric care: integrating patient reported outcomes for tolerability assessment in early phase clinical trials – insights from an expert virtual roundtable

Early phase clinical trials provide an initial evaluation of therapies’ risks and benefits to patients, including safety and tolerability, which typically relies on reporting outcomes by investigator and laboratory assessments. Use of patient-reported outcomes (PROs) to inform risks (tolerability) and benefits (improvement in disease symptoms) is more common in later than early phase trials. We convened a two-day expert roundtable covering: (1) the necessity and feasibility of a universal PRO core conceptual model for early phase trials; (2) the practical integration of PROs in early phase trials to inform tolerability assessment, guide dose decisions, or as real-time safety alerts to enhance investigator-reported adverse events. Participants (n = 22) included: patient advocates, regulators, clinicians, statisticians, pharmaceutical representatives, and PRO methodologists working across diverse clinical areas. In this manuscript, we report major recommendations resulting from the roundtable discussions corresponding to each theme. Additionally, we highlight priority areas necessitating further investigation

Early-to-mid idiopathic Parkinson’s disease shows a more cytotoxic but declined CD8-regulatory peripheral immune profile

Parkinson’s disease (PD) is the second most common neurodegenerative disease. Brain neuroinflammation plays a role in PD pathogenesis. However, the involvement of the peripheral immune system has not been systematically investigated. Here we analyzed >700 combinatorial immunological features in fresh blood of 28 early-to-mid-stage PD patients and 24 matched controls. We found an enhanced cytotoxic immune profile in idiopathic PD patients (iPD), with a higher frequency of terminally-differentiated effector CD8 T (TEMRA), late-differentiated CD8+ natural killer T cells and neutrophils. This immune profile was intensified by elevated serum granzyme A, reduced percentages of CD8+FOXP3+ regulatory T cells and group 2 innate lymphoid cells with immunosuppressive or tolerance-inducing functions. The frequency of CD8 TEMRA was negatively correlated with disease duration, suggesting a contribution to PD pathogenesis. Our work provides a comprehensive map on disturbed peripheral adaptive and innate immune cells in early-to-mid iPD, proposing easily-accessible candidates for early diagnosis and treatments

Recommendations and guidelines from the ISMRM Diffusion Study Group for preclinical diffusion MRI: Part 1 -- In vivo small-animal imaging

The value of in vivo preclinical diffusion MRI (dMRI) is substantial. Small-animal dMRI has been used for methodological development and validation, characterizing the biological basis of diffusion phenomena, and comparative anatomy. Many of the influential works in this field were first performed in small animals or ex vivo samples. The steps from animal setup and monitoring, to acquisition, analysis, and interpretation are complex, with many decisions that may ultimately affect what questions can be answered using the data. This work aims to serve as a reference, presenting selected recommendations and guidelines from the diffusion community, on best practices for preclinical dMRI of in vivo animals. In each section, we also highlight areas for which no guidelines exist (and why), and where future work should focus. We first describe the value that small animal imaging adds to the field of dMRI, followed by general considerations and foundational knowledge that must be considered when designing experiments. We briefly describe differences in animal species and disease models and discuss how they are appropriate for different studies. We then give guidelines for in vivo acquisition protocols, including decisions on hardware, animal preparation, imaging sequences and data processing, including pre-processing, model-fitting, and tractography. Finally, we provide an online resource which lists publicly available preclinical dMRI datasets and software packages, to promote responsible and reproducible research. An overarching goal herein is to enhance the rigor and reproducibility of small animal dMRI acquisitions and analyses, and thereby advance biomedical knowledge.Comment: 69 pages, 6 figures, 1 tabl