Myelin is the self-stacked membrane surrounding axons; it is also the target of several pathological and/or neurodegenerative processes like multiple sclerosis. These processes involve, among others, the hydrolytic attack by phospholipases. In this work we describe the changes in isolated myelin structure after treatment with several secreted PLA2 (sPLA2), by using small angle x-ray scattering (SAXS) measurements. It was observed that myelin treated with all the tested sPLA2s (from cobra and bee venoms and from pig pancreas) preserved the lamellar structure but displayed an enlarged separation between membranes in certain zones. Additionally, the peak due to membrane asymmetry was clearly enhanced. The coherence length was also lower than the non-treated myelin, indicating increased disorder. These SAXS results were complemented by Langmuir film experiments to follow myelin monolayer hydrolysis at the air/water interface by a decrease in electric surface potential at different surface pressures. All enzymes produced hydrolysis with no major qualitative difference between the isoforms tested.
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http://dx.doi.org/10.1016/j.bbamem.2015.10.017 | DOI Listing |
Neuroradiology
January 2025
Department of Imaging Sciences and Interventional Radiology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Thiruvananthapuram, 695011, Kerala, India.
Purpose: Synthetic MR is a quantitative MRI method that measures tissue relaxation times and generates multiple contrast-weighted images using suitable algorithms. The present article principally discusses the multiple dynamic multiple echo (MDME) technique of synthetic MR and briefly describes other quantitative MR sequences.
Methods: Using illustrative cases, various applications of the MDME sequence in neuroradiology are explained.
Magn Reson Med
January 2025
Department of Physical Medicine and Rehabilitation of the Affiliated Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, China.
Purpose: Filter-exchange imaging (FEXI) and diffusion time (t)-dependent kurtosis imaging (DKI(t)) are two diffusion-based methods that have been proposed for in vivo measurements of water exchange rates. Few studies have directly compared these methods. We aimed to investigate whether FEXI and DKI(t) yield comparable water exchange measurements in the human brain in vivo.
View Article and Find Full Text PDFJ Neuroinflammation
January 2025
Department of Translational Neuroscience, Barrow Neurological Institute, Phoenix, AZ, 85013, USA.
The ApoE ε4 allele (APOEε4) is a major genetic risk factor for sporadic Alzheimer's disease (AD) and is linked to demyelination and cognitive decline. However, its effects on the lipid transporters apolipoprotein E (ApoE) and fatty acid-binding protein 7 (Fabp7), which are crucial for the maintenance of myelin in white matter (WM) during the progression of AD remain underexplored. To evaluate the effects of APOEε4 on ApoE, Fabp7 and myelin in the WM of the frontal cortex (FC), we examined individuals carrying one ε4 allele that came to autopsy with a premortem clinical diagnosis of no cognitive impairment (NCI), mild cognitive impairment (MCI) and mild to moderate AD compared with non-carrier counterparts.
View Article and Find Full Text PDFFluids Barriers CNS
January 2025
Laboratory for Therapeutic and Diagnostic Antibodies, KU Leuven - University of Leuven, O&N II Herestraat 49 box 820, 3000, Leuven, Belgium.
Background: Therapeutic antibodies for the treatment of neurological disease show great potential, but their applications are rather limited due to limited brain exposure. The most well-studied approach to enhance brain influx of protein therapeutics, is receptor-mediated transcytosis (RMT) by targeting nutrient receptors to shuttle protein therapeutics over the blood-brain barrier (BBB) along with their endogenous cargos. While higher brain exposure is achieved with RMT, the timeframe is short due to rather fast brain clearance.
View Article and Find Full Text PDFMol Psychiatry
January 2025
Institut de Neurociències, Department de Bioquímica i Biologia Molecular, Facultat de Medicina, Universitat Autònoma de Barcelona, Bellaterra, Barcelona, Spain.
Alzheimer's disease (AD) is characterized by memory loss and neuropsychiatric symptoms associated with cerebral amyloid-β (Aβ) and tau pathologies, but whether and how these factors differentially disrupt neural circuits remains unclear. Here, we investigated the vulnerability of memory and emotional circuits to Aβ and tau pathologies in mice expressing mutant human amyloid precursor protein (APP), Tau or both APP/Tau in excitatory neurons. APP/Tau mice develop age- and sex-dependent Aβ and phosphorylated tau pathologies, the latter exacerbated at early stages, in vulnerable brain regions.
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