Purpose: To observe the tumor responses during photodynamic therapy in a murine glioblastoma model using chemical exchange saturation transfer (CEST) MRI and to compare the treatment effectiveness between single photodynamic therapy (sPDT) and repeated PDT (rePDT).
Methods: After tumor cell implantation in NSG mouse brain (n = 27), mice were subjected to four PDT sessions (rePDT), sPDT after the administration of 5-aminolevulinic acid 6 h before each session, and a non-PDT session (control). A 630-nm LED light was used to effectuate PDT.
A composite scaffold composed of a porous scaffold and hydrogel filling can facilitate engraftment, survival, and retention in cell transplantation processes. This study presents a composite scaffold made of poly(ε-caprolactone) (PCL) and methacrylated hyaluronic acid (MeHA) hydrogel and describes the corresponding physical properties (surface area, porosity, and mechanical strength) and host response (angiogenesis and fibrosis) after subcutaneous transplantation. Specifically, we synthesise MeHA with different degrees of substitution and fabricate a PCL scaffold with different porosities.
View Article and Find Full Text PDFChemical exchange saturation transfer (CEST) MRI is a molecular imaging tool that provides physiological information about tissues, making it an invaluable tool for disease diagnosis and guided treatment. Its clinical application requires the acquisition of high-resolution images capable of accurately identifying subtle regional changes in vivo, while simultaneously maintaining a high level of spectral resolution. However, the acquisition of such high-resolution images is time consuming, presenting a challenge for practical implementation in clinical settings.
View Article and Find Full Text PDFTreating glioblastoma and monitoring treatment response non-invasively remain challenging. Here, we developed a robust approach using a drug-loaded liposomal hydrogel that is mechanically compatible with the brain, and, simultaneously, we successfully monitored early tumor response using Chemical Exchange Saturation Transfer (CEST) MRI. This CEST-detectable liposomal hydrogel was optimized based on a sustainable drug release and a soft hydrogel for the brain tumor, which is unfavorable for tumor cell proliferation.
View Article and Find Full Text PDFThe fluid transport of cerebrospinal fluid (CSF) and interstitial fluid in surrounding tissues plays an important role in the drainage pathway that facilitates waste clearance from the brain. This pathway is known as the glymphatic or perivascular system, and its functions are dependent on aquaporin-4 (AQP4). Recently, magnetization transfer indirect spin labeling (MISL) magnetic resonance imaging (MRI) has been proposed as a noninvasive and noncontrast-enhanced method for detecting water exchange between CSF and brain tissue.
View Article and Find Full Text PDFTraumatic brain injury (TBI) and stroke share a common pathophysiology that worsens over time due to secondary tissue injury caused by sustained inflammatory response. However, studies on pharmacological interventions targeting the complex secondary injury cascade have failed to show efficacy. Here, we demonstrated that low-dose ionizing radiation (LDIR) reduced lesion size and reversed motor deficits after TBI and photothrombotic stroke.
View Article and Find Full Text PDFThe article from this special issue was previously published in NMR In Biomedicine , Volume 35, Issue 3, 2022. For completeness we are including the title page of the article below. The full text of the article can be read in Issue 35:3 on Wiley Online Library: https://doi.
View Article and Find Full Text PDFChemical exchange saturation transfer (CEST) sensitively detects molecular alterations in the brain, such as relayed nuclear Overhauser effect (rNOE) CEST contrast at -3.5 ppm representing aliphatic protons in both lipids and proteins, and CEST contrast at 3.5 ppm correlating with amide proton in proteins.
View Article and Find Full Text PDFImage guided nose-to-brain drug delivery provides a non-invasive way to monitor drug delivered to the brain, and the intranasal administration could increase effective dose via bypassing Blood Brain Barrier (BBB). Here, we investigated the imaging of liposome-based drug delivery to the brain via intranasal administration, in which the liposome could penetrate mucus and could be detected by chemical exchange saturation transfer (CEST) magnetic resonance imaging (MRI) at 3T field strength. Liposomes were loaded with a computed tomography (CT) contrast agent, iohexol (Ioh-Lipo), which has specific amide protons exchanging at 4.
View Article and Find Full Text PDFACS Appl Mater Interfaces
December 2022
Imaging pHe of the tumor microenvironment has paramount importance for characterizing aggressive, invasive tumors, as well as therapeutic responses. Here, a robust approach to image pH changes in the tumor microenvironment longitudinally and during sodium bicarbonate treatment was reported. The pH-sensing microbeads were designed and prepared based on materials approved for clinical use, i.
View Article and Find Full Text PDFBackground: Noninvasive imaging of molecular alterations after intracerebral hemorrhage (ICH) could provide valuable information to guide and monitor treatments. Chemical exchange saturation transfer (CEST) magnetic resonance imaging has demonstrated promises in identifying proliferation, necrosis, and changes in cellularity in brain tumors. Here, we applied CEST magnetic resonance imaging to monitor molecular changes in hematoma without and with treatment noninvasively over 2 weeks at 3T using endogenous contrast.
View Article and Find Full Text PDFChemical exchange saturation transfer (CEST) magnetic resonance imaging (MRI) detects molecules in their natural forms in a sensitive and non-invasive manner. This makes it a robust approach to assess brain tumors and related molecular alterations using endogenous molecules, such as proteins/peptides, and drugs approved for clinical use. In this review, we will discuss the promises of CEST MRI in the identification of tumors, tumor grading, detecting molecular alterations related to isocitrate dehydrogenase (IDH) and O-6-methylguanine-DNA methyltransferase (MGMT), assessment of treatment effects, and using multiple contrasts of CEST to develop theranostic approaches for cancer treatments.
View Article and Find Full Text PDFImaging hydrogel-based local drug delivery to the brain after tumor resection has implications for refining treatments, especially for brain tumors with poor prognosis and high recurrence rate. Here, we developed a series of self-healing chitosan-dextran (CD)-based hydrogels for drug delivery to the brain. These hydrogels are injectable, self-healing, mechanically compatible, and detectable by chemical exchange saturation transfer magnetic resonance imaging (CEST MRI).
View Article and Find Full Text PDFMultiple sclerosis (MS) is an autoimmune disease of the central nervous system in which the immune system attacks the myelin and axons, consequently leading to demyelination and axonal injury. Magnetic resonance imaging (MRI) plays a pivotal role in the diagnosis of MS, and currently various types of MRI techniques have been used to detect the pathology of MS based on unique mechanisms. In this study, we applied the relayed nuclear Overhauser effect weighted (rNOEw) imaging to study human MS at clinical 3T.
View Article and Find Full Text PDFWe investigated three dynamic glucose-enhanced (DGE) MRI methods for sensitively monitoring glucose uptake and clearance in both brain parenchyma and cerebrospinal fluid (CSF) at clinical field strength (3 T). By comparing three sequences, namely, Carr-Purcell-Meiboom-Gill (CPMG), on-resonance variable delay multipulse (onVDMP), and on-resonance spin-lock (onSL), a high-sensitivity DGE MRI scheme with truncated multilinear singular value decomposition (MLSVD) denoising was proposed. The CPMG method showed the highest sensitivity in detecting the parenchymal DGE signal among the three methods, while both onVDMP and onSL were more robust for CSF DGE imaging.
View Article and Find Full Text PDFPurpose: To optimize and apply deep neural network based CEST (deepCEST) and apparent exchange dependent-relaxation (deepAREX) for imaging the mouse brain with Alzheimer's disease (AD) at 3T MRI.
Methods: CEST and T data of central and anterior brain slices of 10 AD mice and 10 age-matched wild type (WT) mice were acquired at a 3T animal MRI scanner. The networks of deepCEST/deepAREX were optimized and trained on the WT data.
Altered cerebral glucose uptake is one of the hallmarks of Alzheimer's disease (AD). A dynamic glucose-enhanced (DGE) magnetic resonance imaging (MRI) approach was developed to simultaneously monitor d-glucose uptake and clearance in both brain parenchyma and cerebrospinal fluid (CSF). We observed substantially higher uptake in parenchyma of young (6 months) transgenic AD mice compared to age-matched wild-type (WT) mice.
View Article and Find Full Text PDFAdjuvant treatment using local drug delivery is applied in treating glioblastoma multiforme (GBM) after tumor resection. However, there are no non-invasive imaging techniques available for tracking the compositional changes of hydrogel-based drug treatment. : We developed Chemical Exchange Saturation Transfer Magnetic Resonance Imaging (CEST MRI) detectable and injectable liposomal hydrogel to monitor these events at 3T clinical field.
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