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Haast RAM, Kashyap S, Ivanov D, Yousif MD, DeKraker J, Poser BA, Khan AR. Insights into hippocampal perfusion using high-resolution, multi-modal 7T MRI. Proc Natl Acad Sci U S A 2024; 121:e2310044121. [PMID: 38446857 PMCID: PMC10945835 DOI: 10.1073/pnas.2310044121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Accepted: 12/26/2023] [Indexed: 03/08/2024] Open
Abstract
We present a comprehensive study on the non-invasive measurement of hippocampal perfusion. Using high-resolution 7 tesla arterial spin labeling (ASL) data, we generated robust perfusion maps and observed significant variations in perfusion among hippocampal subfields, with CA1 exhibiting the lowest perfusion levels. Notably, these perfusion differences were robust and already detectable with 50 perfusion-weighted images per subject, acquired in 5 min. To understand the underlying factors, we examined the influence of image quality metrics, various tissue microstructure and morphometric properties, macrovasculature, and cytoarchitecture. We observed higher perfusion in regions located closer to arteries, demonstrating the influence of vascular proximity on hippocampal perfusion. Moreover, ex vivo cytoarchitectonic features based on neuronal density differences appeared to correlate stronger with hippocampal perfusion than morphometric measures like gray matter thickness. These findings emphasize the interplay between microvasculature, macrovasculature, and metabolic demand in shaping hippocampal perfusion. Our study expands the current understanding of hippocampal physiology and its relevance to neurological disorders. By providing in vivo evidence of perfusion differences between hippocampal subfields, our findings have implications for diagnosis and potential therapeutic interventions. In conclusion, our study provides a valuable resource for extensively characterizing hippocampal perfusion.
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Affiliation(s)
- Roy A. M. Haast
- Centre of Functional and Metabolic Mapping, Robarts Research Institute, Western University, London, ONN6A 3K7, Canada
| | - Sriranga Kashyap
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht6200, The Netherlands
- Krembil Brain Institute, University Health Network, Toronto, ONM5G 2C4, Canada
| | - Dimo Ivanov
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht6200, The Netherlands
| | - Mohamed D. Yousif
- Centre of Functional and Metabolic Mapping, Robarts Research Institute, Western University, London, ONN6A 3K7, Canada
| | - Jordan DeKraker
- Montreal Neurological Institute and Hospital, McGill University, Montreal, QCH3A 0G4, Canada
| | - Benedikt A. Poser
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht6200, The Netherlands
| | - Ali R. Khan
- Centre of Functional and Metabolic Mapping, Robarts Research Institute, Western University, London, ONN6A 3K7, Canada
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Haast RAM, Kashyap S, Ivanov D, Yousif MD, DeKraker J, Poser BA, Khan AR. Novel insights into hippocampal perfusion using high-resolution, multi-modal 7T MRI. bioRxiv 2023:2023.07.19.549533. [PMID: 37503042 PMCID: PMC10370151 DOI: 10.1101/2023.07.19.549533] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/29/2023]
Abstract
We present a comprehensive study on the non-invasive measurement of hippocampal perfusion. Using high-resolution 7 Tesla arterial spin labelling data, we generated robust perfusion maps and observed significant variations in perfusion among hippocampal subfields, with CA1 exhibiting the lowest perfusion levels. Notably, these perfusion differences were robust and detectable even within five minutes and just fifty perfusion-weighted images per subject. To understand the underlying factors, we examined the influence of image quality metrics, various tissue microstructure and morphometry properties, macrovasculature and cytoarchitecture. We observed higher perfusion in regions located closer to arteries, demonstrating the influence of vascular proximity on hippocampal perfusion. Moreover, ex vivo cytoarchitectonic features based on neuronal density differences appeared to correlate stronger with hippocampal perfusion than morphometric measures like gray matter thickness. These findings emphasize the interplay between microvasculature, macrovasculature, and metabolic demand in shaping hippocampal perfusion. Our study expands the current understanding of hippocampal physiology and its relevance to neurological disorders. By providing in vivo evidence of perfusion differences between hippocampal subfields, our findings have implications for diagnosis and potential therapeutic interventions. In conclusion, our study provides a valuable resource for extensively characterising hippocampal perfusion.
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Affiliation(s)
- Roy A M Haast
- Centre of Functional and Metabolic Mapping, Western University, London, Ontario, Canada
| | - Sriranga Kashyap
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, Netherlands
- Krembil Brain Institute, University Health Network, Toronto, Ontario, Canada
| | - Dimo Ivanov
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, Netherlands
| | - Mohamed D Yousif
- Centre of Functional and Metabolic Mapping, Western University, London, Ontario, Canada
| | - Jordan DeKraker
- Montreal Neurological Institute and Hospital, McGill University, Montreal, Quebec, Canada
| | - Benedikt A Poser
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, Netherlands
| | - Ali R Khan
- Centre of Functional and Metabolic Mapping, Western University, London, Ontario, Canada
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Yousif MD, Al-Natour MA, Cavanagh R, Abouselo A, Apebende EA, Ghaemmaghami A, Kim DH, Aylott JW, Taresco V, Chauhan VM, Alexander C. Correction to "Facile Dye-Initiated Polymerization of Lactide-Glycolide Generates Highly Fluorescent Poly(lactic- co-glycolic Acid) for Enhanced Characterization of Cellular Delivery". ACS Macro Lett 2022; 11:1224. [PMID: 36201467 DOI: 10.1021/acsmacrolett.2c00570] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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DeKraker J, Haast RAM, Yousif MD, Karat B, Lau JC, Köhler S, Khan AR. Automated hippocampal unfolding for morphometry and subfield segmentation with HippUnfold. eLife 2022; 11:77945. [PMID: 36519725 PMCID: PMC9831605 DOI: 10.7554/elife.77945] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Accepted: 12/13/2022] [Indexed: 12/16/2022] Open
Abstract
Like neocortical structures, the archicortical hippocampus differs in its folding patterns across individuals. Here, we present an automated and robust BIDS-App, HippUnfold, for defining and indexing individual-specific hippocampal folding in MRI, analogous to popular tools used in neocortical reconstruction. Such tailoring is critical for inter-individual alignment, with topology serving as the basis for homology. This topological framework enables qualitatively new analyses of morphological and laminar structure in the hippocampus or its subfields. It is critical for refining current neuroimaging analyses at a meso- as well as micro-scale. HippUnfold uses state-of-the-art deep learning combined with previously developed topological constraints to generate uniquely folded surfaces to fit a given subject's hippocampal conformation. It is designed to work with commonly employed sub-millimetric MRI acquisitions, with possible extension to microscopic resolution. In this paper, we describe the power of HippUnfold in feature extraction, and highlight its unique value compared to several extant hippocampal subfield analysis methods.
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Affiliation(s)
- Jordan DeKraker
- Robarts Research Institute, Schulich School of Medicine and Dentistry, The University of Western OntarioLondonCanada,Western Institute for Neuroscience, The University of Western OntarioLondonCanada
| | - Roy AM Haast
- Robarts Research Institute, Schulich School of Medicine and Dentistry, The University of Western OntarioLondonCanada
| | - Mohamed D Yousif
- Robarts Research Institute, Schulich School of Medicine and Dentistry, The University of Western OntarioLondonCanada
| | - Bradley Karat
- Robarts Research Institute, Schulich School of Medicine and Dentistry, The University of Western OntarioLondonCanada
| | - Jonathan C Lau
- Robarts Research Institute, Schulich School of Medicine and Dentistry, The University of Western OntarioLondonCanada,Department of Clinical Neurological Sciences, Division of Neurosurgery, Schulich School of Medicine & Dentistry, The University of Western OntarioLondonCanada,School of Biomedical Engineering, The University of Western OntarioLondonCanada
| | - Stefan Köhler
- Western Institute for Neuroscience, The University of Western OntarioLondonCanada,Department of Psychology, Faculty of Social Science, The University of Western OntarioLondonCanada
| | - Ali R Khan
- Robarts Research Institute, Schulich School of Medicine and Dentistry, The University of Western OntarioLondonCanada,Western Institute for Neuroscience, The University of Western OntarioLondonCanada,School of Biomedical Engineering, The University of Western OntarioLondonCanada,Department of Medical Biophysics, Schulich School of Medicine and Dentistry, The University of Western OntarioLondonCanada
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Al-Natour MA, Yousif MD, Cavanagh R, Abouselo A, Apebende EA, Ghaemmaghami A, Kim DH, Aylott JW, Taresco V, Chauhan VM, Alexander C. Facile Dye-Initiated Polymerization of Lactide-Glycolide Generates Highly Fluorescent Poly(lactic- co-glycolic Acid) for Enhanced Characterization of Cellular Delivery. ACS Macro Lett 2020; 9:431-437. [PMID: 35648548 DOI: 10.1021/acsmacrolett.9b01014] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Poly(lactic-co-glycolic acid) (PLGA) is a versatile synthetic copolymer that is widely used in pharmaceutical applications. This is because it is well-tolerated in the body, and copolymers of varying physicochemical properties are readily available via ring-opening polymerization. However, native PLGA polymers are hard to track as drug delivery carriers when delivered to subcellular spaces, due to the absence of an easily accessible "handle" for fluorescent labeling. Here we show a one-step, scalable, solvent-free, synthetic route to fluorescent blue (2-aminoanthracene), green (5-aminofluorescein), and red (rhodamine-6G) PLGA, in which every polymer chain in the sample is fluorescently labeled. The utility of initiator-labeled PLGA was demonstrated through the preparation of nanoparticles, capable of therapeutic subcellular delivery to T-helper-precursor-1 (THP-1) macrophages, a model cell line for determining in vitro biocompatibility and particle uptake. Super resolution confocal fluorescence microscopy imaging showed that dye-initiated PLGA nanoparticles were internalized to punctate regions and retained bright fluorescence over at least 24 h. In comparison, PLGA nanoparticles with 5-aminofluorescein introduced by conventional nanoprecipitation/encapsulation showed diffuse and much lower fluorescence intensity in the same cells and over the same time periods. The utility of this approach for in vitro drug delivery experiments was demonstrated through the concurrent imaging of the fluorescent drug doxorubicin (λex = 480 nm, λem = 590 nm) with carrier 5-aminofluorescein PLGA, also in THP-1 cells, in which the intracellular locations of the drug and the polymer could be clearly visualized. Finally, the dye-labeled particles were evaluated in an in vivo model, via delivery to the nematode Caenorhabditis elegans, with bright fluorescence again apparent in the internal tract after 3 h. The results presented in this manuscript highlight the ease of synthesis of highly fluorescent PLGA, which could be used to augment tracking of future therapeutics and accelerate in vitro and in vivo characterization of delivery systems prior to clinical translation.
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Affiliation(s)
- Mohammad A. Al-Natour
- School of Pharmacy, Boots Science Building, University of Nottingham, Nottingham NG7 2RD, United Kingdom
- Division of Immunology, School of Life Sciences, Faculty of Medicine and Health Sciences, Queen’s Medical Centre, University of Nottingham, Nottingham, United Kingdom
- The Faculty of Pharmacy and Medical Sciences, University of Petra, Amman, Jordan
| | - Mohamed D. Yousif
- School of Pharmacy, Boots Science Building, University of Nottingham, Nottingham NG7 2RD, United Kingdom
| | - Robert Cavanagh
- School of Pharmacy, Boots Science Building, University of Nottingham, Nottingham NG7 2RD, United Kingdom
| | - Amjad Abouselo
- School of Pharmacy, Boots Science Building, University of Nottingham, Nottingham NG7 2RD, United Kingdom
| | - Edward A. Apebende
- School of Chemistry, University of Nottingham, Nottingham NG7 2RD, United Kingdom
| | - Amir Ghaemmaghami
- Division of Immunology, School of Life Sciences, Faculty of Medicine and Health Sciences, Queen’s Medical Centre, University of Nottingham, Nottingham, United Kingdom
| | - Dong-Hyun Kim
- School of Pharmacy, Boots Science Building, University of Nottingham, Nottingham NG7 2RD, United Kingdom
| | - Jonathan W. Aylott
- School of Pharmacy, Boots Science Building, University of Nottingham, Nottingham NG7 2RD, United Kingdom
| | - Vincenzo Taresco
- School of Pharmacy, Boots Science Building, University of Nottingham, Nottingham NG7 2RD, United Kingdom
- School of Chemistry, University of Nottingham, Nottingham NG7 2RD, United Kingdom
| | - Veeren M. Chauhan
- School of Pharmacy, Boots Science Building, University of Nottingham, Nottingham NG7 2RD, United Kingdom
| | - Cameron Alexander
- School of Pharmacy, Boots Science Building, University of Nottingham, Nottingham NG7 2RD, United Kingdom
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Medwid S, Li MM, Knauer MJ, Lin K, Mansell SE, Schmerk CL, Zhu C, Griffin KE, Yousif MD, Dresser GK, Schwarz UI, Kim RB, Tirona RG. Fexofenadine and Rosuvastatin Pharmacokinetics in Mice with Targeted Disruption of Organic Anion Transporting Polypeptide 2B1. Drug Metab Dispos 2019; 47:832-842. [DOI: 10.1124/dmd.119.087619] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Accepted: 05/20/2019] [Indexed: 01/06/2023] Open
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