Positron Emission Tomography Imaging of Synaptic Dysfunction in Parkinson’s Disease

Parkinson’s disease(PD)is one of the most common neurodegenerative diseases with a complex pathogenesis.Aggregations formed by abnormal deposition of alpha-synuclein(αSyn)lead to synapse dysfunction of the dopamine and non-dopamine systems.The loss of dopaminergic neurons and concomitant alterations in non-dopaminergic function in PD constitute its primary pathological manifestation.Positron emission tomography(PET),as a representative molecular imaging technique,enables the non-invasive visualization,characterization,and quantification of biological processes at cellular and molecular levels.Imaging synaptic function with PET would provide insights into the mechanisms underlying PD and facilitate the optimization of clinical management.In this review,we focus on the synaptic dysfunction associated with theαSyn pathology of PD,summarize various related targets and radiopharmaceuticals,and discuss applications and perspectives of PET imaging of synaptic dysfunction in PD.

Magneto-mechanical effect of magnetic microhydrogel for improvement of magnetic neuro-stimulation

Superparamagnetic iron oxide(SPIO)nanoparticles play an important role in mediating precise and effective magnetic neurostimulation and can help overcome limitations related to penetration depth and spatial resolution.However,nanoparticles readily diffuse in vivo,decreasing the spatial resolution and activation efficiency.In this study,we employed a microfluidic means to fabricate injectable microhydrogels encapsulated with SPIO nanoparticles,which significantly improved the stability of nanoparticles,increased the magnetic properties,reinforced the stimulation effectivity.The fabricated magnetic microhydrogels were highly uniform in size and sphericity,enabling minimally invasive injection into brain tissue.The long-term residency in the cortex up to 22 weeks and the safety of brain tissue were shown using a mouse model.In addition,we quantitatively determined the magneto-mechanical force yielded by only one magnetic microhydrogel using a video-based method.The force was found to be within 7–8 pN under 10 Hz magnetic stimulation by both theoretical simulation and experimental measurement.Lastly,electrophysiological measurement of brain slices showed that the magnetic microhydrogels offer significant advantages in terms of neural activation relative to dissociative SPIO nanoparticles.A universal strategy is thus offered for performing magnetic neuro-stimulation with an improved prospect for biomedical translation.

Phenomic Imaging

Human phenomics is defned as the comprehensive collection of observable phenotypes and characteristics infuenced by a complex interplay among factors at multiple scales.These factors include genes,epigenetics at the microscopic level,organs,microbiome at the mesoscopic level,and diet and environmental exposures at the macroscopic level.“Phenomic imaging”utilizes various imaging techniques to visualize and measure anatomical structures,biological functions,metabolic processes,and biochemical activities across diferent scales,both in vivo and ex vivo.Unlike conventional medical imaging focused on disease diagnosis,phenomic imaging captures both normal and abnormal traits,facilitating detailed correlations between macro-and micro-phenotypes.This approach plays a crucial role in deciphering phenomes.This review provides an overview of diferent phenomic imaging modalities and their applications in human phenomics.Additionally,it explores the associations between phenomic imaging and other omics disciplines,including genomics,transcriptomics,proteomics,immunomics,and metabolomics.By integrating phenomic imaging with other omics data,such as genomics and metabolomics,a comprehensive understanding of biological systems can be achieved.This integration paves the way for the development of new therapeutic approaches and diagnostic tools.

Protocol for Brain Magnetic Resonance Imaging and Extraction of Imaging‑Derived Phenotypes from the China Phenobank Project

Imaging-derived phenotypes(IDPs)have been increasingly used in population-based cohort studies in recent years.As widely reported,magnetic resonance imaging(MRI)is an important imaging modality for assessing the anatomical structure and function of the brain with high resolution and excellent soft-tissue contrast.The purpose of this article was to describe the imaging protocol of the brain MRI in the China Phenobank Project(CHPP).Each participant underwent a 30-min brain MRI scan as part of a 2-h whole-body imaging protocol in CHPP.The brain imaging sequences included T1-magnetization that prepared rapid gradient echo,T2 fuid-attenuated inversion-recovery,magnetic resonance angiography,difusion MRI,and resting-state functional MRI.The detailed descriptions of image acquisition,interpretation,and post-processing were provided in this article.The measured IDPs included volumes of brain subregions,cerebral vessel geometrical parameters,microstructural tracts,and function connectivity metrics.