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Impact of sarcopenia and obesity on mortality in older adults with SARS-CoV-2 infection: automated deep learning body composition analysis in the NAPKON-SUEP cohort
No full textHow can Alzheimer's disease blood‐based biomarkers reach clinical practice?
Full text linkINTRODUCTION
Alzheimer's disease (AD) diagnosis has been based largely on clinical symptoms, despite their limited sensitivity and specificity. Biomarker use was proposed to support a more accurate and timely diagnosis. However, neuroimaging or cerebrospinal fluid (CSF) is rarely used in primary care due to their perceived invasiveness, cost, and need for appropriate infrastructure. Blood-based biomarkers (BBMs) could represent an economical, minimally invasive alternative, but barriers exist to a seamless translation to the clinic.
METHODS
Ten international experienced AD clinicians and biomarker experts participated in a diagnostic roundtable to discuss the implementation of BBMs for diagnosing early symptomatic AD.
RESULTS
The participants proposed an optimal AD diagnostic pathway and highlighted three main gaps to implementing BBMs for early symptomatic AD diagnosis: limited real-world data, resource gaps, and system barriers.
DISCUSSION
Although BBMs could streamline the AD diagnostic pathway, further real-world evidence and collaboration among multiple stakeholders are needed
Real-World Laboratory Analysis of Molecular Biomarkers in Multiple Sclerosis Centers in Central-Eastern European Countries Covering 107 Million Inhabitants
Full text linkA multicenter molecular biomarker survey was conducted in Multiple Sclerosis (MS) centers across Central-Eastern European countries, encompassing a population of 107 million. Our aim was to provide a “snapshot” for future studies investigating the use of molecular biomarkers in MS. A self-report questionnaire was distributed via email to MS centers in seven Central-Eastern European countries (Croatia, Czech Republic, Poland, Romania, Serbia, Slovakia, and Slovenia) and to four reference centers (two in Austria, one in Germany, and one in Denmark), focusing on cerebrospinal fluid (CSF) analysis and molecular biomarkers in MS. Responding centers routinely request CSF oligoclonal band (OCB) testing in suspected MS cases, although no consensus exists on the number of CSF-restricted bands required to define OCB positivity, either within or between countries. More than half of the surveyed centers in the Czech Republic, Slovakia, Slovenia, and the reference centers request kappa free light chain (κFLC) testing in patients with suspected MS. Neurofilament light chain (NfL) is frequently used as a molecular biomarker for MS in Romania, Slovakia, and the reference centers. In summary, besides the use of CSF-specific OCB there is no consensus among the surveyed countries regarding the use of molecular biomarkers in MS
Diffusion tensor imaging of sequential neuropathological patterns in progressive supranuclear palsy
Full text linkBackground and objective: A neuropathological cerebral staging concept for progressive supranuclear palsy (PSP) has been proposed that tau inclusions in PSP may progress in a sequential regional pattern. The objective was to develop a hypothesis-guided region/tract of interest-based (ROI/TOI) approach to use diffusion tensor imaging (DTI) targeted to analyze in vivo the regions that are prone to be involved at each neuropathological stage of PSP.
Methods: Two data cohorts were analyzed: cohort A of 78 PSP patients [55 Richardson’s syndrome (PSP-RS) and 23 PSP with predominant parkinsonism (PSP-P)] and 63 controls, recorded at 3.0T at multiple sites, and a single-site cohort B constituted by 1.5T data of 66 PSP patients (46 PSP-RS and 20 PSP-P) and 44 controls. In cohort A, 21 PSP patients (13 PSP-RS and 8 PSP-P) and 17 controls obtained a follow-up scan after 17 months. Whole brain-based spatial statistics (WBSS) was used to identify the alterations in PSP patients vs. controls. The combined ROI- and TOI-based approach targeted structures that are prone to be involved during the course of PSP.
Results: WBSS demonstrated alterations predominantly in brainstem/midbrain, basal ganglia, and frontal lobe, more pronounced in the longitudinal data. Statistical analyses of the ROIs/TOIs showed a sequential pattern of structures that were assigned to previously defined neuropathological steps.
Conclusion: The combined ROI- and TOI-based DTI approach was able to map the disease stages of PSP in vivo cross-sectionally and longitudinally, lending support to DTI as a technical marker for imaging disease progression according to PSP stages. This approach might be useful as a tool for stratification of PSP patients MRI with respect to its proposed neuropathological progression in future longitudinal and autopsy-controlled studies
Microsurgical Lymphatic Vessel Transplantation for Chronic Lymphedema: Long-Term Evaluation of Volume Reduction and Lymphatic Transport Kinetics
Full text linkCortex folding by combined progenitor expansion and adhesion-controlled neuronal migration
Full text linkFolding of the mammalian cerebral cortex into sulcal fissures and gyral peaks is the result of complex processes that are incompletely understood. Previously we showed that genetic deletion of Flrt1/3 adhesion molecules causes folding of the smooth mouse cortex into sulci resulting from increased lateral dispersion and faster neuron migration, without progenitor expansion. Here, we show in mice that combining the Flrt1/3 double knockout with an additional genetic deletion that causes progenitor expansion, greatly enhances cortex folding. Expansion of intermediate progenitors by deletion of Cep83 leads to a relative increase in Flrt-mutant neurons resulting in enhanced formation of sulci. Expansion of apical progenitors by deletion of Fgf10 leads to a relative reduction in Flrt-mutant neurons resulting in enhanced formation of gyri. These results together with computational modeling identify key developmental mechanisms, such as adhesive properties, cell densities and migration of cortical neurons, that cooperate to promote cortical gyrification
TGFα controls checkpoints in CNS resident and infiltrating immune cells to promote resolution of inflammation
Full text linkAfter acute lesions in the central nervous system (CNS), the interaction of microglia, astrocytes, and infiltrating immune cells decides over their resolution or chronification. However, this CNS-intrinsic cross-talk is poorly characterized. Analyzing cerebrospinal fluid (CSF) samples of Multiple Sclerosis (MS) patients as well as CNS samples of female mice with experimental autoimmune encephalomyelitis (EAE), the animal model of MS, we identify microglia-derived TGFα as key factor driving recovery. Through mechanistic in vitro studies, in vivo treatment paradigms, scRNA sequencing, CRISPR-Cas9 genetic perturbation models and MRI in the EAE model, we show that together with other glial and non-glial cells, microglia secrete TGFα in a highly regulated temporospatial manner in EAE. Here, TGFα contributes to recovery by decreasing infiltrating T cells, pro-inflammatory myeloid cells, oligodendrocyte loss, demyelination, axonal damage and neuron loss even at late disease stages. In a therapeutic approach in EAE, blood-brain barrier penetrating intranasal application of TGFα attenuates pro-inflammatory signaling in astrocytes and CNS infiltrating immune cells while promoting neuronal survival and lesion resolution. Together, microglia-derived TGFα is an important mediator of glial-immune crosstalk, highlighting its therapeutic potential in resolving acute CNS inflammation
PRIAMOS: A technique for mixing embedding media for freely adjusting pH value and refractive index (RI) for optical clearing (OC) of whole tissue samples
No full textInvestigations of biological samples often require sample transparency, which is achieved by embedding the sample in a high-refractive index (RI) medium to obtain a homogenous RI distribution in the sample, referred to as optical clearing (OC). Here, we introduce a method for designing embedding media with an increased RI by increasing molecular orbitals, which is achieved by replacing elements in molecules commonly used for OC with elements possessing a more pronounced polarisability. Briefly, we took the established embedding medium Glycerol and exchanged the OH-groups by Thiol-groups, resulting in an embedding medium with very similar properties, but with a higher refractive index. We describe a procedure—abbreviated PRIAMOS—to render biological samples transparent using an RI-matching liquid, which we refer to as pH-value and Refractive Index Adjustment by Mixing highly polarisable molecular Orbital Substances. We focus on optical clearing in three-dimensional tissue samples whilst preserving fluorescence of fluorescent labels. The clearing procedure requires 2–3 days, yielding highly transparent samples, preserving the fluorescence of fluorescent proteins like the yellow fluorescent protein (YFP). This is demonstrated on mouse brain samples, imaged with standard confocal microscopy down to 1.6 mm depth, as well as on kidney samples. Mixtures of monothioglycerol, dithioglycerol and tributylamine achieve RI values between 1.52 and 1.57, and an acidity equivalent to pH values between 5 and 8. Our PRIAMOS approach can serve as a guideline for optimising optical clearing protocols
