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Liu C, Cárdenas-Rivera A, Teitelbaum S, Birmingham A, Alfadhel M, Yaseen MA. Neuroinflammation increases oxygen extraction in a mouse model of Alzheimer's disease. Alzheimers Res Ther 2024; 16:78. [PMID: 38600598 PMCID: PMC11005245 DOI: 10.1186/s13195-024-01444-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Accepted: 03/31/2024] [Indexed: 04/12/2024]
Abstract
BACKGROUND Neuroinflammation, impaired metabolism, and hypoperfusion are fundamental pathological hallmarks of early Alzheimer's disease (AD). Numerous studies have asserted a close association between neuroinflammation and disrupted cerebral energetics. During AD progression and other neurodegenerative disorders, a persistent state of chronic neuroinflammation reportedly exacerbates cytotoxicity and potentiates neuronal death. Here, we assessed the impact of a neuroinflammatory challenge on metabolic demand and microvascular hemodynamics in the somatosensory cortex of an AD mouse model. METHODS We utilized in vivo 2-photon microscopy and the phosphorescent oxygen sensor Oxyphor 2P to measure partial pressure of oxygen (pO2) and capillary red blood cell flux in cortical microvessels of awake mice. Intravascular pO2 and capillary RBC flux measurements were performed in 8-month-old APPswe/PS1dE9 mice and wildtype littermates on days 0, 7, and 14 of a 14-day period of lipopolysaccharide-induced neuroinflammation. RESULTS Before the induced inflammatory challenge, AD mice demonstrated reduced metabolic demand but similar capillary red blood cell flux as their wild type counterparts. Neuroinflammation provoked significant reductions in cerebral intravascular oxygen levels and elevated oxygen extraction in both animal groups, without significantly altering red blood cell flux in capillaries. CONCLUSIONS This study provides evidence that neuroinflammation alters cerebral oxygen demand at the early stages of AD without substantially altering vascular oxygen supply. The results will guide our understanding of neuroinflammation's influence on neuroimaging biomarkers for early AD diagnosis.
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Affiliation(s)
- Chang Liu
- Department of Bioengineering, Northeastern University, Boston, MA, 02115, USA
| | | | - Shayna Teitelbaum
- Department of Bioengineering, Northeastern University, Boston, MA, 02115, USA
| | - Austin Birmingham
- Department of Bioengineering, Northeastern University, Boston, MA, 02115, USA
| | - Mohammed Alfadhel
- Department of Bioengineering, Northeastern University, Boston, MA, 02115, USA
| | - Mohammad A Yaseen
- Department of Bioengineering, Northeastern University, Boston, MA, 02115, USA.
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Liu C, Cardenas-Rivera A, Teitelbaum S, Birmingham A, Alfadhel M, Yaseen MA. Neuroinflammation increases oxygen extraction in a mouse model of Alzheimer's disease. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.16.562353. [PMID: 37905082 PMCID: PMC10614808 DOI: 10.1101/2023.10.16.562353] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/02/2023]
Abstract
Neuroinflammation, impaired metabolism, and hypoperfusion are fundamental pathological hallmarks of early Alzheimer's disease (AD). Numerous studies have asserted a close association between neuroinflammation and disrupted cerebral energetics. During AD progression and other neurodegenerative disorders, a persistent state of chronic neuroinflammation reportedly exacerbates cytotoxicity and potentiates neuronal death. Here, we assessed the impact of a neuroinflammatory challenge on metabolic demand and microvascular hemodynamics in the somatosensory cortex of an AD mouse model. We utilized in vivo 2-photon microscopy and the phosphorescent oxygen sensor Oxyphor 2P to measure partial pressure of oxygen (pO2) and capillary red blood cell flux in cortical microvessels of awake mice. Intravascular pO2 and capillary RBC flux measurements were performed in 8-month-old APPswe/PS1dE9 mice and wildtype littermates on days 0, 7, and 14 of a 14-day period of lipopolysaccaride-induced neuroinflammation. Before the induced inflammatory challenge, AD mice demonstrated reduced metabolic demand but similar capillary red blood cell flux as their wild type counterparts. Neuroinflammation provoked significant reductions in cerebral intravascular oxygen levels and elevated oxygen extraction in both animal groups, without significantly altering red blood cell flux in capillaries. This study provides evidence that neuroinflammation alters cerebral oxygen demand at the early stages of AD without substantially altering vascular oxygen supply. The results will guide our understanding of neuroinflammation's influence on neuroimaging biomarkers for early AD diagnosis.
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3
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Liu G, Wang J, Wei Z, Fang C, Shen K, Qian C, Qi C, Li T, Gao P, Wong PC, Lu H, Cao X, Wan M. Elevated PDGF-BB from Bone Impairs Hippocampal Vasculature by Inducing PDGFRβ Shedding from Pericytes. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2023; 10:e2206938. [PMID: 37102631 PMCID: PMC10369301 DOI: 10.1002/advs.202206938] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Revised: 04/11/2023] [Indexed: 06/19/2023]
Abstract
Evidence suggests a unique association between bone aging and neurodegenerative/cerebrovascular disorders. However, the mechanisms underlying bone-brain interplay remain elusive. Here platelet-derived growth factor-BB (PDGF-BB) produced by preosteoclasts in bone is reported to promote age-associated hippocampal vascular impairment. Aberrantly elevated circulating PDGF-BB in aged mice and high-fat diet (HFD)-challenged mice correlates with capillary reduction, pericyte loss, and increased blood-brain barrier (BBB) permeability in their hippocampus. Preosteoclast-specific Pdgfb transgenic mice with markedly high plasma PDGF-BB concentration faithfully recapitulate the age-associated hippocampal BBB impairment and cognitive decline. Conversely, preosteoclast-specific Pdgfb knockout mice have attenuated hippocampal BBB impairment in aged mice or HFD-challenged mice. Persistent exposure of brain pericytes to high concentrations of PDGF-BB upregulates matrix metalloproteinase 14 (MMP14), which promotes ectodomain shedding of PDGF receptor β (PDGFRβ) from pericyte surface. MMP inhibitor treatment alleviates hippocampal pericyte loss and capillary reduction in the conditional Pdgfb transgenic mice and antagonizes BBB leakage in aged mice. The findings establish the role of bone-derived PDGF-BB in mediating hippocampal BBB disruption and identify the ligand-induced PDGFRβ shedding as a feedback mechanism for age-associated PDGFRβ downregulation and the consequent pericyte loss.
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Affiliation(s)
- Guanqiao Liu
- Department of Orthopaedic SurgeryJohns Hopkins University School of MedicineRoss Building, Room 232, 720 Rutland AvenueBaltimoreMD21205USA
| | - Jiekang Wang
- Department of Orthopaedic SurgeryJohns Hopkins University School of MedicineRoss Building, Room 232, 720 Rutland AvenueBaltimoreMD21205USA
| | - Zhiliang Wei
- The Russell H. Morgan Department of Radiology and Radiological ScienceThe Johns Hopkins University School of MedicineBaltimoreMD21205USA
| | - Ching‐Lien Fang
- Department of Orthopaedic SurgeryJohns Hopkins University School of MedicineRoss Building, Room 232, 720 Rutland AvenueBaltimoreMD21205USA
| | - Ke Shen
- Department of Orthopaedic SurgeryJohns Hopkins University School of MedicineRoss Building, Room 232, 720 Rutland AvenueBaltimoreMD21205USA
| | - Cheng Qian
- Department of Orthopaedic SurgeryJohns Hopkins University School of MedicineRoss Building, Room 232, 720 Rutland AvenueBaltimoreMD21205USA
| | - Cheng Qi
- Department of Orthopaedic SurgeryJohns Hopkins University School of MedicineRoss Building, Room 232, 720 Rutland AvenueBaltimoreMD21205USA
| | - Tong Li
- Department of PathologyJohns Hopkins University School of MedicineBaltimoreMD21205USA
| | - Peisong Gao
- Division of Allergy and Clinical ImmunologyJohns Hopkins University School of MedicineBaltimoreMD21224USA
| | - Philip C. Wong
- Department of PathologyJohns Hopkins University School of MedicineBaltimoreMD21205USA
- Department of NeuroscienceJohns Hopkins University School of MedicineBaltimoreMD21205USA
| | - Hanzhang Lu
- The Russell H. Morgan Department of Radiology and Radiological ScienceThe Johns Hopkins University School of MedicineBaltimoreMD21205USA
| | - Xu Cao
- Department of Orthopaedic SurgeryJohns Hopkins University School of MedicineRoss Building, Room 232, 720 Rutland AvenueBaltimoreMD21205USA
| | - Mei Wan
- Department of Orthopaedic SurgeryJohns Hopkins University School of MedicineRoss Building, Room 232, 720 Rutland AvenueBaltimoreMD21205USA
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4
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Wei Z, Li Y, Bibic A, Duan W, Xu J, Lu H. Toward accurate cerebral blood flow estimation in mice after accounting for anesthesia. Front Physiol 2023; 14:1169622. [PMID: 37123257 PMCID: PMC10130671 DOI: 10.3389/fphys.2023.1169622] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2023] [Accepted: 04/03/2023] [Indexed: 05/02/2023] Open
Abstract
Purpose: To improve the accuracy of cerebral blood flow (CBF) measurement in mice by accounting for the anesthesia effects. Methods: The dependence of CBF on anesthesia dose and time was investigated by simultaneously measuring respiration rate (RR) and heart rate (HR) under four different anesthetic regimens. Quantitative CBF was measured by a phase-contrast (PC) MRI technique. RR was evaluated with a mouse monitoring system (MouseOX) while HR was determined using an ultrashort-TE MRI sequence. CBF, RR, and HR were recorded dynamically with a temporal resolution of 1 min in a total of 19 mice. Linear regression models were used to investigate the relationships among CBF, anesthesia dose, RR, and HR. Results: CBF, RR, and HR all showed a significant dependence on anesthesia dose (p < 0.0001). However, the dose in itself was insufficient to account for the variations in physiological parameters, in that they showed a time-dependent change even for a constant dose. RR and HR together can explain 52.6% of the variations in CBF measurements, which is greater than the amount of variance explained by anesthesia dose (32.4%). Based on the multi-parametric regression results, a model was proposed to correct the anesthesia effects in mouse CBF measurements, specificallyC B F c o r r e c t e d = C B F + 0.58 R R - 0.41 H R - 32.66 D o s e . We also reported awake-state CBF in mice to be 142.0 ± 8.8 mL/100 g/min, which is consistent with the model-predicted value. Conclusion: The accuracy of CBF measurement in mice can be improved by using a correction model that accounts for respiration rate, heart rate, and anesthesia dose.
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Affiliation(s)
- Zhiliang Wei
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, United States
- F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Research Institute, Baltimore, MD, United States
| | - Yuguo Li
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, United States
- F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Research Institute, Baltimore, MD, United States
| | - Adnan Bibic
- F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Research Institute, Baltimore, MD, United States
| | - Wenzhen Duan
- Division of Neurobiology, Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, United States
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Jiadi Xu
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, United States
- F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Research Institute, Baltimore, MD, United States
| | - Hanzhang Lu
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, United States
- F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Research Institute, Baltimore, MD, United States
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, United States
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Wei Z, Liu H, Lin Z, Yao M, Li R, Liu C, Li Y, Xu J, Duan W, Lu H. Non-contrast assessment of blood-brain barrier permeability to water in mice: An arterial spin labeling study at cerebral veins. Neuroimage 2023; 268:119870. [PMID: 36640948 PMCID: PMC9908858 DOI: 10.1016/j.neuroimage.2023.119870] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Revised: 11/15/2022] [Accepted: 01/10/2023] [Indexed: 01/13/2023] Open
Abstract
Blood-brain barrier (BBB) plays a critical role in protecting the brain from toxins and pathogens. However, in vivo tools to assess BBB permeability are scarce and often require the use of exogenous contrast agents. In this study, we aimed to develop a non-contrast arterial-spin-labeling (ASL) based MRI technique to estimate BBB permeability to water in mice. By determining the relative fraction of labeled water spins that were exchanged into the brain tissue as opposed to those that remained in the cerebral veins, we estimated indices of global BBB permeability to water including water extraction fraction (E) and permeability surface-area product (PS). First, using multiple post-labeling delay ASL experiments, we estimated the bolus arrival time (BAT) of the labeled spins to reach the great vein of Galen (VG) to be 691.2 ± 14.5 ms (N = 5). Next, we investigated the dependence of the VG ASL signal on labeling duration and identified an optimal imaging protocol with a labeling duration of 1200 ms and a PLD of 100 ms. Quantitative E and PS values in wild-type mice were found to be 59.9 ± 3.2% and 260.9 ± 18.9 ml/100 g/min, respectively. In contrast, mice with Huntington's disease (HD) revealed a significantly higher E (69.7 ± 2.4%, P = 0.026) and PS (318.1 ± 17.1 ml/100 g/min, P = 0.040), suggesting BBB breakdown in this mouse model. Reproducibility studies revealed a coefficient-of-variation (CoV) of 4.9 ± 1.7% and 6.1 ± 1.2% for E and PS, respectively. The proposed method may open new avenues for preclinical research on pathophysiological mechanisms of brain diseases and therapeutic trials in animal models.
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Affiliation(s)
- Zhiliang Wei
- The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, 600N. Wolfe Street, Park 326, Baltimore, MD 21287, USA; F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Research Institute, Baltimore, MD, USA.
| | - Hongshuai Liu
- Division of Neurobiology, Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, 600 North Wolfe Street, CMSC 8-121, Baltimore, MD 21287, USA
| | - Zixuan Lin
- The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, 600N. Wolfe Street, Park 326, Baltimore, MD 21287, USA
| | - Minmin Yao
- Division of Neurobiology, Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, 600 North Wolfe Street, CMSC 8-121, Baltimore, MD 21287, USA
| | - Ruoxuan Li
- Division of Neurobiology, Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, 600 North Wolfe Street, CMSC 8-121, Baltimore, MD 21287, USA
| | - Chang Liu
- Division of Neurobiology, Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, 600 North Wolfe Street, CMSC 8-121, Baltimore, MD 21287, USA
| | - Yuguo Li
- The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, 600N. Wolfe Street, Park 326, Baltimore, MD 21287, USA; F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Research Institute, Baltimore, MD, USA
| | - Jiadi Xu
- The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, 600N. Wolfe Street, Park 326, Baltimore, MD 21287, USA; F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Research Institute, Baltimore, MD, USA
| | - Wenzhen Duan
- Division of Neurobiology, Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, 600 North Wolfe Street, CMSC 8-121, Baltimore, MD 21287, USA; The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
| | - Hanzhang Lu
- The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, 600N. Wolfe Street, Park 326, Baltimore, MD 21287, USA; F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Research Institute, Baltimore, MD, USA; Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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6
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Wang L, Hu Z, Chen H, Sheng X, Qin R, Shao P, Yang Z, Yao W, Zhao H, Xu Y, Bai F. Applying Retinal Vascular Structures Characteristics Coupling with Cortical Visual System in Alzheimer's Disease Spectrum Patients. Brain Sci 2023; 13:brainsci13020339. [PMID: 36831883 PMCID: PMC9954049 DOI: 10.3390/brainsci13020339] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Revised: 02/08/2023] [Accepted: 02/14/2023] [Indexed: 02/19/2023] Open
Abstract
Cortical visual system dysfunction is closely related to the progression of Alzheimer's Disease (AD), while retinal vascular structures play an important role in the integrity of the function of the visual network and are a potential biomarker of AD. This study explored the association between the cortical visual system and retinal vascular structures in AD-spectrum patients, and it established a screening tool to detect preclinical AD based on these parameters identified in a retinal examination. A total of 42 subjects were enrolled and were distributed into two groups: 22 patients with cognitive impairment and 20 healthy controls. All participants underwent neuropsychological tests, optical coherence tomography angiography and resting-state fMRI imaging. Seed-based functional connectivity analysis was used to construct the cortical visual network. The association of functional connectivity of the cortical visual system and retinal vascular structures was further explored in these subjects. This study found that the cognitive impairment group displayed prominently decreased functional connectivity of the cortical visual system mainly involving the right inferior temporal gyrus, left supramarginal gyrus and right postcentral gyrus. Meanwhile, we observed that retinal vascular structure characteristics deteriorated with the decline in functional connectivity in the cortical visual system. Our study provided novel insights into the aberrant cortical visual system in patients with cognitive impairment that strongly emphasized the critical role of retinal vascular structure characteristics, which could be used as potential biomarkers for diagnosing and monitoring the progression of AD.
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Affiliation(s)
- Lianlian Wang
- Department of Neurology, Nanjing Drum Tower Hospital Clinical College of Jiangsu University, Nanjing 210008, China
| | - Zheqi Hu
- Department of Neurology, Nanjing Drum Tower Hospital of the Affiliated Hospital of Nanjing University Medical School, the State Key Laboratory of Pharmaceutical Biotechnology, Institute of Brain Science, Nanjing University, Nanjing 210008, China
| | - Haifeng Chen
- Department of Neurology, Nanjing Drum Tower Hospital of the Affiliated Hospital of Nanjing University Medical School, the State Key Laboratory of Pharmaceutical Biotechnology, Institute of Brain Science, Nanjing University, Nanjing 210008, China
- Jiangsu Province Stroke Center for Diagnosis and Therapy, Nanjing 210008, China
- Nanjing Neuropsychiatry Clinic Medical Center, Nanjing 210008, China
| | - Xiaoning Sheng
- Department of Neurology, Nanjing Drum Tower Hospital of the Affiliated Hospital of Nanjing University Medical School, the State Key Laboratory of Pharmaceutical Biotechnology, Institute of Brain Science, Nanjing University, Nanjing 210008, China
| | - Ruomeng Qin
- Department of Neurology, Nanjing Drum Tower Hospital of the Affiliated Hospital of Nanjing University Medical School, the State Key Laboratory of Pharmaceutical Biotechnology, Institute of Brain Science, Nanjing University, Nanjing 210008, China
- Jiangsu Province Stroke Center for Diagnosis and Therapy, Nanjing 210008, China
- Nanjing Neuropsychiatry Clinic Medical Center, Nanjing 210008, China
| | - Pengfei Shao
- Department of Neurology, Nanjing Drum Tower Hospital of the Affiliated Hospital of Nanjing University Medical School, the State Key Laboratory of Pharmaceutical Biotechnology, Institute of Brain Science, Nanjing University, Nanjing 210008, China
| | - Zhiyuan Yang
- Department of Neurology, Nanjing Drum Tower Hospital of the Affiliated Hospital of Nanjing University Medical School, the State Key Laboratory of Pharmaceutical Biotechnology, Institute of Brain Science, Nanjing University, Nanjing 210008, China
| | - Weina Yao
- Department of Neurology, Nanjing Drum Tower Hospital Clinical College of Jiangsu University, Nanjing 210008, China
| | - Hui Zhao
- Department of Neurology, Nanjing Drum Tower Hospital of the Affiliated Hospital of Nanjing University Medical School, the State Key Laboratory of Pharmaceutical Biotechnology, Institute of Brain Science, Nanjing University, Nanjing 210008, China
- Jiangsu Province Stroke Center for Diagnosis and Therapy, Nanjing 210008, China
- Nanjing Neuropsychiatry Clinic Medical Center, Nanjing 210008, China
| | - Yun Xu
- Department of Neurology, Nanjing Drum Tower Hospital of the Affiliated Hospital of Nanjing University Medical School, the State Key Laboratory of Pharmaceutical Biotechnology, Institute of Brain Science, Nanjing University, Nanjing 210008, China
- Jiangsu Province Stroke Center for Diagnosis and Therapy, Nanjing 210008, China
- Nanjing Neuropsychiatry Clinic Medical Center, Nanjing 210008, China
| | - Feng Bai
- Department of Neurology, Nanjing Drum Tower Hospital of the Affiliated Hospital of Nanjing University Medical School, the State Key Laboratory of Pharmaceutical Biotechnology, Institute of Brain Science, Nanjing University, Nanjing 210008, China
- Jiangsu Province Stroke Center for Diagnosis and Therapy, Nanjing 210008, China
- Nanjing Neuropsychiatry Clinic Medical Center, Nanjing 210008, China
- Geriatric Medicine Center, Affiliated Taikang Xianlin Drum Tower Hospital, Medical School of Nanjing University, Nanjing 210008, China
- Correspondence: ; Tel.: +86-25-83105960
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7
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Jiang D, Lu H. Cerebral oxygen extraction fraction MRI: Techniques and applications. Magn Reson Med 2022; 88:575-600. [PMID: 35510696 PMCID: PMC9233013 DOI: 10.1002/mrm.29272] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Revised: 03/20/2022] [Accepted: 03/29/2022] [Indexed: 12/20/2022]
Abstract
The human brain constitutes 2% of the body's total mass but uses 20% of the oxygen. The rate of the brain's oxygen utilization can be derived from a knowledge of cerebral blood flow and the oxygen extraction fraction (OEF). Therefore, OEF is a key physiological parameter of the brain's function and metabolism. OEF has been suggested to be a useful biomarker in a number of brain diseases. With recent advances in MRI techniques, several MRI-based methods have been developed to measure OEF in the human brain. These MRI OEF techniques are based on the T2 of blood, the blood signal phase, the magnetic susceptibility of blood-containing voxels, the effect of deoxyhemoglobin on signal behavior in extravascular tissue, and the calibration of the BOLD signal using gas inhalation. Compared to 15 O PET, which is considered the "gold standard" for OEF measurement, MRI-based techniques are non-invasive, radiation-free, and are more widely available. This article provides a review of these emerging MRI-based OEF techniques. We first briefly introduce the role of OEF in brain oxygen homeostasis. We then review the methodological aspects of different categories of MRI OEF techniques, including their signal mechanisms, acquisition methods, and data analyses. The strengths and limitations of the techniques are discussed. Finally, we review key applications of these techniques in physiological and pathological conditions.
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Affiliation(s)
- Dengrong Jiang
- The Russell H. Morgan Department of Radiology & Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Hanzhang Lu
- The Russell H. Morgan Department of Radiology & Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Research Institute, Baltimore, Maryland, USA
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8
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Robb WH, Khan OA, Ahmed HA, Li J, Moore EE, Cambronero FE, Pechman KR, Liu D, Gifford KA, Landman BA, Donahue MJ, Hohman TJ, Jefferson AL. Lower cerebral oxygen utilization is associated with Alzheimer's disease-related neurodegeneration and poorer cognitive performance among apolipoprotein E ε4 carriers. J Cereb Blood Flow Metab 2022; 42:642-655. [PMID: 34743630 PMCID: PMC9051148 DOI: 10.1177/0271678x211056393] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Oxygen extraction fraction (OEF) and cerebral metabolic rate of oxygen (CMRO2) are markers of cerebral oxygen homeostasis and metabolism that may offer insights into abnormal changes in brain aging. The present study cross-sectionally related OEF and CMRO2 to cognitive performance and structural neuroimaging variables among older adults (n = 246, 74 ± 7 years, 37% female) and tested whether apolipoprotein E (APOE)-ε4 status modified these associations. Main effects of OEF and CMRO2 were null (p-values >0.06), and OEF interactions with APOE-ε4 status on cognitive and structural imaging outcomes were null (p-values >0.06). However, CMRO2 interacted with APOE-ε4 status on language (p = 0.002), executive function (p = 0.03), visuospatial (p = 0.005), and episodic memory performances (p = 0.03), and on hippocampal (p = 0.006) and inferior lateral ventricle volumes (p = 0.02). In stratified analyses, lower oxygen metabolism related to worse language (p = 0.02) and episodic memory performance (p = 0.03) among APOE-ε4 carriers only. Associations between CMRO2 and cognitive performance were primarily driven by APOE-ε4 carriers with existing cognitive impairment. Congruence across language and episodic memory results as well as hippocampal and inferior lateral ventricle volume findings suggest that APOE-ε4 may interact with cerebral oxygen metabolism in the pathogenesis of Alzheimer's disease and related neurodegeneration.
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Affiliation(s)
- W Hudson Robb
- Vanderbilt Memory and Alzheimer's Center, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Omair A Khan
- Vanderbilt Memory and Alzheimer's Center, Vanderbilt University Medical Center, Nashville, TN, USA.,Department of Biostatistics, 12328Vanderbilt University Medical Center, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Humza A Ahmed
- Vanderbilt Memory and Alzheimer's Center, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Judy Li
- Vanderbilt Memory and Alzheimer's Center, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Elizabeth E Moore
- Vanderbilt Memory and Alzheimer's Center, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Francis E Cambronero
- Vanderbilt Memory and Alzheimer's Center, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Kimberly R Pechman
- Vanderbilt Memory and Alzheimer's Center, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Dandan Liu
- Vanderbilt Memory and Alzheimer's Center, Vanderbilt University Medical Center, Nashville, TN, USA.,Department of Biostatistics, 12328Vanderbilt University Medical Center, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Katherine A Gifford
- Vanderbilt Memory and Alzheimer's Center, Vanderbilt University Medical Center, Nashville, TN, USA.,Department of Neurology, 12328Vanderbilt University Medical Center, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Bennett A Landman
- Department of Neurology, 12328Vanderbilt University Medical Center, Vanderbilt University Medical Center, Nashville, TN, USA.,Department of Biomedical Engineering, 5718Vanderbilt University, Vanderbilt University, Nashville, TN, USA.,Department of Electrical Engineering and Computer Science, 5718Vanderbilt University, Vanderbilt University, Nashville, TN, USA.,Department of Radiology and Radiological Sciences, 12328Vanderbilt University Medical Center, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Manus J Donahue
- Department of Neurology, 12328Vanderbilt University Medical Center, Vanderbilt University Medical Center, Nashville, TN, USA.,Department of Radiology and Radiological Sciences, 12328Vanderbilt University Medical Center, Vanderbilt University Medical Center, Nashville, TN, USA.,Department of Psychiatry and Behavioral Sciences, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Timothy J Hohman
- Vanderbilt Memory and Alzheimer's Center, Vanderbilt University Medical Center, Nashville, TN, USA.,Department of Neurology, 12328Vanderbilt University Medical Center, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Angela L Jefferson
- Vanderbilt Memory and Alzheimer's Center, Vanderbilt University Medical Center, Nashville, TN, USA.,Department of Neurology, 12328Vanderbilt University Medical Center, Vanderbilt University Medical Center, Nashville, TN, USA.,Department of Medicine, 12328Vanderbilt University Medical Center, Vanderbilt University Medical Center, Nashville, TN, USA
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9
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Neuroimaging of Mouse Models of Alzheimer’s Disease. Biomedicines 2022; 10:biomedicines10020305. [PMID: 35203515 PMCID: PMC8869427 DOI: 10.3390/biomedicines10020305] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Revised: 01/25/2022] [Accepted: 01/25/2022] [Indexed: 12/23/2022] Open
Abstract
Magnetic resonance imaging (MRI) and positron emission tomography (PET) have made great strides in the diagnosis and our understanding of Alzheimer’s Disease (AD). Despite the knowledge gained from human studies, mouse models have and continue to play an important role in deciphering the cellular and molecular evolution of AD. MRI and PET are now being increasingly used to investigate neuroimaging features in mouse models and provide the basis for rapid translation to the clinical setting. Here, we provide an overview of the human MRI and PET imaging landscape as a prelude to an in-depth review of preclinical imaging in mice. A broad range of mouse models recapitulate certain aspects of the human AD, but no single model simulates the human disease spectrum. We focused on the two of the most popular mouse models, the 3xTg-AD and the 5xFAD models, and we summarized all known published MRI and PET imaging data, including contrasting findings. The goal of this review is to provide the reader with broad framework to guide future studies in existing and future mouse models of AD. We also highlight aspects of MRI and PET imaging that could be improved to increase rigor and reproducibility in future imaging studies.
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Ni R. Magnetic Resonance Imaging in Tauopathy Animal Models. Front Aging Neurosci 2022; 13:791679. [PMID: 35145392 PMCID: PMC8821905 DOI: 10.3389/fnagi.2021.791679] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Accepted: 12/27/2021] [Indexed: 11/13/2022] Open
Abstract
The microtubule-associated protein tau plays an important role in tauopathic diseases such as Alzheimer’s disease and primary tauopathies such as progressive supranuclear palsy and corticobasal degeneration. Tauopathy animal models, such as transgenic, knock-in mouse and rat models, recapitulating tauopathy have facilitated the understanding of disease mechanisms. Aberrant accumulation of hyperphosphorylated tau contributes to synaptic deficits, neuroinflammation, and neurodegeneration, leading to cognitive impairment in animal models. Recent advances in molecular imaging using positron emission tomography (PET) and magnetic resonance imaging (MRI) have provided valuable insights into the time course of disease pathophysiology in tauopathy animal models. High-field MRI has been applied for in vivo imaging in animal models of tauopathy, including diffusion tensor imaging for white matter integrity, arterial spin labeling for cerebral blood flow, resting-state functional MRI for functional connectivity, volumetric MRI for neurodegeneration, and MR spectroscopy. In addition, MR contrast agents for non-invasive imaging of tau have been developed recently. Many preclinical MRI indicators offer excellent translational value and provide a blueprint for clinical MRI in the brains of patients with tauopathies. In this review, we summarized the recent advances in using MRI to visualize the pathophysiology of tauopathy in small animals. We discussed the outstanding challenges in brain imaging using MRI in small animals and propose a future outlook for visualizing tau-related alterations in the brains of animal models.
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Affiliation(s)
- Ruiqing Ni
- Institute for Biomedical Engineering, ETH Zurich and University of Zurich, Zurich, Switzerland
- Institute for Regenerative Medicine, University of Zurich, Zurich, Switzerland
- *Correspondence: Ruiqing Ni,
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Ni R. Magnetic Resonance Imaging in Animal Models of Alzheimer's Disease Amyloidosis. Int J Mol Sci 2021; 22:12768. [PMID: 34884573 PMCID: PMC8657987 DOI: 10.3390/ijms222312768] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Revised: 11/18/2021] [Accepted: 11/23/2021] [Indexed: 02/07/2023] Open
Abstract
Amyloid-beta (Aβ) plays an important role in the pathogenesis of Alzheimer's disease. Aberrant Aβ accumulation induces neuroinflammation, cerebrovascular alterations, and synaptic deficits, leading to cognitive impairment. Animal models recapitulating the Aβ pathology, such as transgenic, knock-in mouse and rat models, have facilitated the understanding of disease mechanisms and the development of therapeutics targeting Aβ. There is a rapid advance in high-field MRI in small animals. Versatile high-field magnetic resonance imaging (MRI) sequences, such as diffusion tensor imaging, arterial spin labeling, resting-state functional MRI, anatomical MRI, and MR spectroscopy, as well as contrast agents, have been developed for preclinical imaging in animal models. These tools have enabled high-resolution in vivo structural, functional, and molecular readouts with a whole-brain field of view. MRI has been used to visualize non-invasively the Aβ deposits, synaptic deficits, regional brain atrophy, impairment in white matter integrity, functional connectivity, and cerebrovascular and glymphatic system in animal models of Alzheimer's disease amyloidosis. Many of the readouts are translational toward clinical MRI applications in patients with Alzheimer's disease. In this review, we summarize the recent advances in MRI for visualizing the pathophysiology in amyloidosis animal models. We discuss the outstanding challenges in brain imaging using MRI in small animals and propose future outlook in visualizing Aβ-related alterations in the brains of animal models.
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Affiliation(s)
- Ruiqing Ni
- Institute for Biomedical Engineering, ETH Zurich & University of Zurich, 8093 Zurich, Switzerland;
- Institute for Regenerative Medicine, University of Zurich, 8952 Zurich, Switzerland
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