In a groundbreaking study, researchers at the UMH-CSIC Neurosciences Institute have devised an innovative, non-invasive approach to image microglial and astrocyte activation in brain gray matter using diffusion-weighted magnetic resonance imaging (dw-MRI), according to a press release published by the institution on Friday. The development could have applications in Alzheimer’s disease and other forms of dementia, Parkinson’s disease and multiple sclerosis†
The first signal of this type of MRI
“This is the first time that the signal from this type of MRI (dw-MRI) has been shown to detect activation of microglia and astrocytes, with specific footprints for each cell population. This strategy we used reflects the morphological changes that have been validated.” after mortem by quantitative immunohistochemistry,” noted: dr. Silvia deSantis and Dr. Santiago Canals, both of the Institute of Neurosciences UMH-CSIC.
The previous gold standard for imaging brain inflammation in vivo was positron emission tomography (PET). However, this process was difficult to generalize and involved exposure to ionizing radiation.
It was therefore reserved for use in vulnerable populations and in longitudinal studies. On the other hand, diffusion-weighted MRI has the unique ability to image the brain microstructure in vivo non-invasively and with high resolution by capturing the random movement of water molecules in the brain parenchyma to generate contrast in MRI images. .
A cohort of healthy people with high resolution
The new approach was tested in a high-resolution cohort of healthy humans,” in which we performed a reproducibility analysis. The significant association with known microglia density patterns in the human brain supports the method’s utility for generating reliable glia biomarkers. that characterizing, using this technique, relevant aspects of tissue microstructure during inflammation, non-invasively and longitudinally, can have a huge impact on our understanding of the pathophysiology of many brain disorders, and can enhance current diagnostic practice and treatment monitoring strategies for neurodegenerative diseases. transform,” Silvia de Santis added.
Furthermore, it has been found that the technique is sensitive and specific for detecting inflammation with and without neurodegeneration, so that the two conditions can be distinguished. It also makes it possible to distinguish between inflammatory and demyelination features of multiple sclerosis.
To validate the model, the researchers used an established paradigm of inflammation in rats based on intracerebral administration of lipopolysaccharide (LPS) and an established paradigm of demyelination based on focal administration of lysolecithin to demonstrate that the developed biomarkers do not tissue changes commonly found in brain disorders.
The new method could revolutionize the treatment of neurodegenerative diseases. The study has been published in the news scientific progress†
Although glia are increasingly implicated in the pathophysiology of psychiatric and neurodegenerative disorders, available methods for in vivo imaging of these cells include either invasive procedures or positron emission tomography radiotracers, which yield low resolution and specificity. Here we present a non-invasive diffusion-weighted magnetic resonance imaging (MRI) method to image changes in glial morphology. Using rat models of neuroinflammation, degeneration and demyelination, we demonstrate that diffusion-weighted MRI carries a fingerprint of microglia and astrocyte activation and that specific signatures of each population can be quantified non-invasively. The method is sensitive to changes in glia morphology and proliferation, providing a quantitative overview of neuroinflammation regardless of the existence of a concomitant neuronal loss or demyelinating injury. We prove the translational value of the approach showing significant associations between MRI and histological microglia markers in humans. This framework has the potential to transform basic and clinical research by clarifying the role of inflammation in health and disease.
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