1
|
Zuroff LR, Green AJ. The Study of Remyelinating Therapies in Multiple Sclerosis: Visual Outcomes as a Window Into Repair. J Neuroophthalmol 2024; 44:143-156. [PMID: 38654413 DOI: 10.1097/wno.0000000000002149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/26/2024]
Abstract
INTRODUCTION Amelioration of disability in multiple sclerosis requires the development of complementary therapies that target neurodegeneration and promote repair. Remyelination is a promising neuroprotective strategy that may protect axons from damage and subsequent neurodegeneration. METHODS A review of key literature plus additional targeted search of PubMed and Google Scholar was conducted. RESULTS There has been a rapid expansion of clinical trials studying putative remyelinating candidates, but further growth of the field is limited by the lack of consensus on key aspects of trial design. We have not yet defined the ideal study population, duration of therapy, or the appropriate outcome measures to detect remyelination in humans. The varied natural history of multiple sclerosis, coupled with the short time frame of phase II clinical trials, requires that we develop and validate biomarkers of remyelination that can serve as surrogate endpoints in clinical trials. CONCLUSIONS We propose that the visual system may be the most well-suited and validated model for the study potential remyelinating agents. In this review, we discuss the pathophysiology of demyelination and summarize the current clinical trial landscape of remyelinating agents. We present some of the challenges in the study of remyelinating agents and discuss current potential biomarkers of remyelination and repair, emphasizing both established and emerging visual outcome measures.
Collapse
Affiliation(s)
- Leah R Zuroff
- Department of Neurology (LZ), Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania; and Department of Neurology (AJG), University of California San Francisco, San Francisco, California
| | | |
Collapse
|
2
|
Brier MR, Taha F. Measuring Pathology in Patients with Multiple Sclerosis Using Positron Emission Tomography. Curr Neurol Neurosci Rep 2023; 23:479-488. [PMID: 37418219 DOI: 10.1007/s11910-023-01285-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/28/2023] [Indexed: 07/08/2023]
Abstract
PURPOSE OF REVIEW Multiple sclerosis is characterized by a diverse and complex pathology. Clinical relapses, the hallmark of the disease, are accompanied by focal white matter lesions with intense inflammatory and demyelinating activity. Prevention of these relapses has been the major focus of pharmaceutical development, and it is now possible to dramatically reduce this inflammatory activity. Unfortunately, disability accumulation persists for many people living with multiple sclerosis owing to ongoing damage within existing lesions, pathology outside of discrete lesions, and other yet unknown factors. Understanding this complex pathological cascade will be critical to stopping progressive multiple sclerosis. Positron emission tomography uses biochemically specific radioligands to quantitatively measure pathological processes with molecular specificity. This review examines recent advances in the understanding of multiple sclerosis facilitated by positron emission tomography and identifies future avenues to expand understanding and treatment options. RECENT FINDINGS An increasing number of radiotracers allow for the quantitative measurement of inflammatory abnormalities, de- and re-myelination, and metabolic disruption associated with multiple sclerosis. The studies have identified contributions of ongoing, smoldering inflammation to accumulating tissue injury and clinical worsening. Myelin studies have quantified the dynamics of myelin loss and recovery. Lastly, metabolic changes have been found to contribute to symptom worsening. The molecular specificity facilitated by positron emission tomography in people living with multiple sclerosis will critically inform efforts to modulate the pathology leading to progressive disability accumulation. Existing studies show the power of this approach applied to multiple sclerosis. This armamentarium of radioligands allows for new understanding of how the brain and spinal cord of people is impacted by multiple sclerosis.
Collapse
Affiliation(s)
- Matthew R Brier
- Department of Neurology, John L Trotter MS Center, Washington University in St. Louis, St. Louis, USA.
| | - Farris Taha
- Department of Neurology, Medical University of South Carolina, Charleston, USA
| |
Collapse
|
3
|
Boyko AN, Dolgushin MB, Karalkina MA. [New neuroimaging methods in assessing the activity of neuroinflammation in multiple sclerosis]. Zh Nevrol Psikhiatr Im S S Korsakova 2023; 123:8-14. [PMID: 37560828 DOI: 10.17116/jnevro20231230728] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/11/2023]
Abstract
The review presents current data on the use of positron emission tomography and single-photon emission computed tomography in multiple sclerosis (MS) to assess the activity of the pathological process, including neuroinflammation, demyelination, activation of microglia, neurodegeneration and local blood flow disorders. These methodologies are a new approach for studying the mechanisms of action and evaluating the clinical effect of disease modifying therapy of MS, especially those capable of penetrating into brain tissue. Among them, the most attention is attracted by cladribine tablets acting on the mechanism of immune reconstitution therapy, most likely with the modulation of immune reactions directly in the brain tissue.
Collapse
Affiliation(s)
- A N Boyko
- Federal Center of Brain and Neurotechnologies of the Federal Medical Biological Agency, Moscow, Russia
- Pirogov Russian National Research Medical University, Moscow, Russia
| | - M B Dolgushin
- Federal Center of Brain and Neurotechnologies of the Federal Medical Biological Agency, Moscow, Russia
| | - M A Karalkina
- Federal Center of Brain and Neurotechnologies of the Federal Medical Biological Agency, Moscow, Russia
| |
Collapse
|
4
|
van der Weijden CWJ, van der Hoorn A, Wang Y, Willemsen ATM, Dierckx RAJO, Lammertsma AA, de Vries EFJ. Investigation of image-derived input functions for non-invasive quantification of myelin density using [ 11C]MeDAS PET. Neuroimage 2022; 264:119772. [PMID: 36436711 DOI: 10.1016/j.neuroimage.2022.119772] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Revised: 11/01/2022] [Accepted: 11/23/2022] [Indexed: 11/27/2022] Open
Abstract
Multiple sclerosis (MS) is an inflammatory demyelinating disease. Current treatments are focussed on immune suppression to modulate pathogenic activity that causes myelin damage. New treatment strategies are needed to prevent demyelination and promote remyelination. Development of such myelin repair therapies require a sensitive and specific biomarker for efficacy evaluation. Recently, it has been shown that quantification of myelin density is possible using [11C]MeDAS PET. This method, however, requires arterial blood sampling to generate an arterial input function (AIF). As the invasive nature of arterial sampling will reduce clinical applicability, the purpose of this study was to assess whether an image-derived input function (IDIF) can be used as an alternative way to facilitate its routine clinical use. Six healthy controls and 11 MS patients underwent MRI and [11C]MeDAS PET with arterial blood sampling. The application of both population-based whole blood-to-plasma conversion and metabolite corrections were assessed for the AIF. Next, summed images of the early time frames (0-70 s) and the frame with the highest blood-brain contrast were used to generate IDIFs. IDIFs were created using either the hottest 2, 4, 6 or 12 voxels, or an isocontour of the hottest 10% voxels of the carotid artery. This was followed by blood-to-plasma conversion and metabolite correction of the IDIF. The application of a population-based metabolite correction of the AIF resulted in high correlations of tracer binding (Ki) within subjects, but variable bias across subjects. All IDIFs had a sharper and higher peak in the blood curves than the AIF, most likely due to dispersion during blood sampling. All IDIF methods resulted in similar high correlations within subjects (r = 0.95-0.98), but highly variable bias across subjects (mean slope=0.90-1.09). Therefore, both the use of population based blood-plasma and metabolite corrections and the generation of the image-derived whole-blood curve resulted in substantial bias in [11C]MeDAS PET quantification, due to high inter-subject variability. Consequently, when unbiased quantification of [11C]MeDAS PET data is required, individual AIF needs to be used.
Collapse
Affiliation(s)
- Chris W J van der Weijden
- Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Hanzeplein 1, Groningen 9713GZ, the Netherlands
| | - Anouk van der Hoorn
- Radiology, University of Groningen, University Medical Center Groningen, Hanzeplein 1, Groningen 9713GZ, the Netherlands
| | - Yanming Wang
- Department of Radiology, Case Western Reserve University, Cleveland, OH 44106, United States
| | - Antoon T M Willemsen
- Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Hanzeplein 1, Groningen 9713GZ, the Netherlands
| | - Rudi A J O Dierckx
- Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Hanzeplein 1, Groningen 9713GZ, the Netherlands
| | - Adriaan A Lammertsma
- Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Hanzeplein 1, Groningen 9713GZ, the Netherlands
| | - Erik F J de Vries
- Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Hanzeplein 1, Groningen 9713GZ, the Netherlands.
| |
Collapse
|
5
|
Zeydan B, Schwarz CG, Przybelski SA, Lesnick TG, Kremers WK, Senjem ML, Kantarci OH, Min PH, Kemp BJ, Jack CR, Kantarci K, Lowe VJ. Comparison of 11C-Pittsburgh Compound B and 18F-Flutemetamol White Matter Binding in PET. J Nucl Med 2022; 63:1239-1244. [PMID: 34916245 PMCID: PMC9364341 DOI: 10.2967/jnumed.121.263281] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Accepted: 11/30/2021] [Indexed: 02/03/2023] Open
Abstract
PET imaging with β-amyloid ligands is emerging as a molecular imaging technique targeting white matter integrity and demyelination. β-amyloid PET ligands such as 11C-Pittsburgh compound B (11C-PiB) have been considered for quantitative measurement of myelin content changes in multiple sclerosis, but 11C-PiB is not commercially available given its short half-life. A 18F PET ligand such as flutemetamol with a longer half-life may be an alternative, but its ability to differentiate white matter hyperintensities (WMH) from normal-appearing white matter (NAWM) and its relationship with age remains to be investigated. Methods: Cognitively unimpaired (CU) older and younger adults (n = 61) were recruited from the community responding to a study advertisement for β-amyloid PET. Participants prospectively underwent MRI, 11C-PiB, and 18F-flutemetamol PET scans. MRI fluid-attenuated inversion recovery images were segmented into WMH and NAWM and registered to the T1-weighted MRI. 11C-PiB and 18F-flutemetamol PET images were also registered to the T1-weighted MRI. 11C-PiB and 18F-flutemetamol SUV ratios (SUVrs) from the WMH and NAWM were calculated using cerebellar crus uptake as a reference for both 11C-PiB and 18F-flutemetamol. Results: The median age was 38 y (range, 30-48 y) in younger adults and 67 y (range, 61-83 y) in older adults. WMH and NAWM SUVrs were higher with 18F-flutemetamol than with 11C-PiB in both older (P < 0.001) and younger (P < 0.001) CU adults. 11C-PiB and 18F-flutemetamol SUVrs were higher in older than in younger CU adults in both WMH (P < 0.001) and NAWM (P < 0.001). 11C-PiB and 18F-flutemetamol SUVrs were higher in NAWM than WMH in both older (P < 0.001) and younger (P < 0.001) CU adults. There was no apparent difference between 11C-PiB and 18F-flutemetamol SUVrs in differentiating WMH from NAWM in older and in younger adults. Conclusion:11C-PiB and 18F-flutemetamol show a similar topographic pattern of uptake in white matter with a similar association with age in WMH and NAWM. 11C-PiB and 18F-flutemetamol can also effectively distinguish between WMH and NAWM. However, given its longer half-life, commercial availability, and higher binding potential, 18F-flutemetamol can be an alternative to 11C-PiB in molecular imaging studies specifically targeting multiple sclerosis to evaluate white matter integrity.
Collapse
Affiliation(s)
- Burcu Zeydan
- Department of Radiology, Mayo Clinic, Rochester, Minnesota
- Department of Neurology, Mayo Clinic, Rochester, Minnesota
| | | | - Scott A Przybelski
- Department of Quantitative Health Sciences, Mayo Clinic, Rochester, Minnesota; and
| | - Timothy G Lesnick
- Department of Quantitative Health Sciences, Mayo Clinic, Rochester, Minnesota; and
| | - Walter K Kremers
- Department of Quantitative Health Sciences, Mayo Clinic, Rochester, Minnesota; and
| | - Matthew L Senjem
- Department of Radiology, Mayo Clinic, Rochester, Minnesota
- Department of Information Technology, Mayo Clinic, Rochester, Minnesota
| | | | - Paul H Min
- Department of Radiology, Mayo Clinic, Rochester, Minnesota
| | - Bradley J Kemp
- Department of Radiology, Mayo Clinic, Rochester, Minnesota
| | | | - Kejal Kantarci
- Department of Radiology, Mayo Clinic, Rochester, Minnesota
| | - Val J Lowe
- Department of Radiology, Mayo Clinic, Rochester, Minnesota;
| |
Collapse
|
6
|
van der Weijden CWJ, Meilof JF, van der Hoorn A, Zhu J, Wu C, Wang Y, Willemsen ATM, Dierckx RAJO, Lammertsma AA, de Vries EFJ. Quantitative assessment of myelin density using [ 11C]MeDAS PET in patients with multiple sclerosis: a first-in-human study. Eur J Nucl Med Mol Imaging 2022; 49:3492-3507. [PMID: 35366079 PMCID: PMC9308583 DOI: 10.1007/s00259-022-05770-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Accepted: 03/19/2022] [Indexed: 12/21/2022]
Abstract
Purpose Multiple sclerosis (MS) is a disease characterized by inflammatory demyelinated lesions. New treatment strategies are being developed to stimulate myelin repair. Quantitative myelin imaging could facilitate these developments. This first-in-man study aimed to evaluate [11C]MeDAS as a PET tracer for myelin imaging in humans. Methods Six healthy controls and 11 MS patients underwent MRI and dynamic [11C]MeDAS PET scanning with arterial sampling. Lesion detection and classification were performed on MRI. [11C]MeDAS time-activity curves of brain regions and MS lesions were fitted with various compartment models for the identification of the best model to describe [11C]MeDAS kinetics. Several simplified methods were compared to the optimal compartment model. Results Visual analysis of the fits of [11C]MeDAS time-activity curves showed no preference for irreversible (2T3k) or reversible (2T4k) two-tissue compartment model. Both volume of distribution and binding potential estimates showed a high degree of variability. As this was not the case for 2T3k-derived net influx rate (Ki), the 2T3k model was selected as the model of choice. Simplified methods, such as SUV and MLAIR2 correlated well with 2T3k-derived Ki, but SUV showed subject-dependent bias when compared to 2T3k. Both the 2T3k model and the simplified methods were able to differentiate not only between gray and white matter, but also between lesions with different myelin densities. Conclusion [11C]MeDAS PET can be used for quantification of myelin density in MS patients and is able to distinguish differences in myelin density within MS lesions. The 2T3k model is the optimal compartment model and MLAIR2 is the best simplified method for quantification. Trial registration. NL7262. Registered 18 September 2018. Supplementary information The online version contains supplementary material available at 10.1007/s00259-022-05770-4.
Collapse
Affiliation(s)
- Chris W J van der Weijden
- Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Hanzeplein 1, Groningen, The Netherlands
| | - Jan F Meilof
- Department of Biomedical Sciences of Cells and Systems, University of Groningen, University Medical Center Groningen, Hanzeplein 1, 9713GZ, Groningen, The Netherlands
- Department of Neurology, Martini Ziekenhuis, Groningen, The Netherlands
| | - Anouk van der Hoorn
- Radiology, University of Groningen, University Medical Center Groningen, Hanzeplein 1, 9713GZ, Groningen, The Netherlands
| | - Junqing Zhu
- Department of Radiology, Case Western Reserve University, Cleveland, OH, 44106, USA
| | - Chunying Wu
- Department of Radiology, Case Western Reserve University, Cleveland, OH, 44106, USA
| | - Yanming Wang
- Department of Radiology, Case Western Reserve University, Cleveland, OH, 44106, USA
| | - Antoon T M Willemsen
- Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Hanzeplein 1, Groningen, The Netherlands
| | - Rudi A J O Dierckx
- Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Hanzeplein 1, Groningen, The Netherlands
| | - Adriaan A Lammertsma
- Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Hanzeplein 1, Groningen, The Netherlands
| | - Erik F J de Vries
- Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Hanzeplein 1, Groningen, The Netherlands.
| |
Collapse
|
7
|
The Role of Molecular Imaging as a Marker of Remyelination and Repair in Multiple Sclerosis. Int J Mol Sci 2021; 23:ijms23010474. [PMID: 35008899 PMCID: PMC8745199 DOI: 10.3390/ijms23010474] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 12/26/2021] [Accepted: 12/29/2021] [Indexed: 12/14/2022] Open
Abstract
The appearance of new disease-modifying therapies in multiple sclerosis (MS) has revolutionized our ability to fight inflammatory relapses and has immensely improved patients’ quality of life. Although remarkable, this achievement has not carried over into reducing long-term disability. In MS, clinical disability progression can continue relentlessly irrespective of acute inflammation. This “silent” disease progression is the main contributor to long-term clinical disability in MS and results from chronic inflammation, neurodegeneration, and repair failure. Investigating silent disease progression and its underlying mechanisms is a challenge. Standard MRI excels in depicting acute inflammation but lacks the pathophysiological lens required for a more targeted exploration of molecular-based processes. Novel modalities that utilize nuclear magnetic resonance’s ability to display in vivo information on imaging look to bridge this gap. Displaying the CNS through a molecular prism is becoming an undeniable reality. This review will focus on “molecular imaging biomarkers” of disease progression, modalities that can harmoniously depict anatomy and pathophysiology, making them attractive candidates to become the first valid biomarkers of neuroprotection and remyelination.
Collapse
|
8
|
Positron emission tomography in multiple sclerosis - straight to the target. Nat Rev Neurol 2021; 17:663-675. [PMID: 34545219 DOI: 10.1038/s41582-021-00537-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/30/2021] [Indexed: 02/08/2023]
Abstract
Following the impressive progress in the treatment of relapsing-remitting multiple sclerosis (MS), the major challenge ahead is the development of treatments to prevent or delay the irreversible accumulation of clinical disability in progressive forms of the disease. The substrate of clinical progression is neuro-axonal degeneration, and a deep understanding of the mechanisms that underlie this process is a precondition for the development of therapies for progressive MS. PET imaging involves the use of radiolabelled compounds that bind to specific cellular and metabolic targets, thereby enabling direct in vivo measurement of several pathological processes. This approach can provide key insights into the clinical relevance of these processes and their chronological sequence during the disease course. In this Review, we focus on the contribution that PET is making to our understanding of extraneuronal and intraneuronal mechanisms that are involved in the pathogenesis of irreversible neuro-axonal damage in MS. We consider the major challenges with the use of PET in MS and the steps necessary to realize clinical benefits of the technique. In addition, we discuss the potential of emerging PET tracers and future applications of existing compounds to facilitate the identification of effective neuroprotective treatments for patients with MS.
Collapse
|
9
|
18F-florbetapir PET as a marker of myelin integrity across the Alzheimer's disease spectrum. Eur J Nucl Med Mol Imaging 2021; 49:1242-1253. [PMID: 34581847 PMCID: PMC8921113 DOI: 10.1007/s00259-021-05493-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Accepted: 07/08/2021] [Indexed: 01/23/2023]
Abstract
Purpose Recent evidence suggests that PET imaging with amyloid-β (Aβ) tracers can be used to assess myelin integrity in cerebral white matter (WM). Alzheimer’s disease (AD) is characterized by myelin changes that are believed to occur early in the disease course. Nevertheless, the extent to which demyelination, as measured with Aβ PET, contributes to AD progression remains unexplored. Methods Participants with concurrent 18F-florbetapir (FBP) PET, MRI, and cerebrospinal fluid (CSF) examinations were included (241 cognitively normal, 347 Aβ-positive cognitively impaired, and 207 Aβ-negative cognitively impaired subjects). A subset of these participants had also available diffusion tensor imaging (DTI) images (n = 195). We investigated cross-sectional associations of FBP retention in the white matter (WM) with MRI-based markers of WM degeneration, AD clinical progression, and fluid biomarkers. In longitudinal analyses, we used linear mixed models to assess whether FBP retention in normal-appearing WM (NAWM) predicted progression of WM hyperintensity (WMH) burden and clinical decline. Results In AD-continuum individuals, FBP retention in NAWM was (1) higher compared with WMH regions, (2) associated with DTI-based measures of WM integrity, and (3) associated with longitudinal progression of WMH burden. FBP uptake in WM decreased across the AD continuum and with increasingly abnormal CSF biomarkers of AD. Furthermore, FBP retention in the WM was associated with large-calibre axon degeneration as reflected by abnormal plasma neurofilament light chain levels. Low FBP uptake in NAWM predicted clinical decline in preclinical and prodromal AD, independent of demographics, global cortical Aβ, and WMH burden. Most of these associations were also observed in Aβ-negative cognitively impaired individuals. Conclusion These results support the hypothesis that FBP retention in the WM is myelin-related. Demyelination levels progressed across the AD continuum and were associated with clinical progression at early stages, suggesting that this pathologic process might be a relevant degenerative feature in the disease course. Supplementary Information The online version contains supplementary material available at 10.1007/s00259-021-05493-y.
Collapse
|
10
|
Reduced [ 18F]flortaucipir retention in white matter hyperintensities compared to normal-appearing white matter. Eur J Nucl Med Mol Imaging 2021; 48:2283-2294. [PMID: 33475761 DOI: 10.1007/s00259-021-05195-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2020] [Accepted: 01/04/2021] [Indexed: 01/18/2023]
Abstract
PURPOSE Recent research has suggested the use of white matter (WM) reference regions for longitudinal tau-PET imaging. However, tau tracers display affinity for the β-sheet structure formed by myelin, and thus WM lesions might influence tracer retention. Here, we explored whether the tau-sensitive tracer [18F]flortaucipir shows reduced retention in WM hyperintensities (WMH) and how this retention changes over time. METHODS We included 707 participants from the Alzheimer's Disease Neuroimaging Initiative with available [18F]flortaucipir-PET and structural and FLAIR MRI scans. WM segments and WMH were automatically delineated in the structural MRI and FLAIR scans, respectively. [18F]flortaucipir standardized uptake value ratios (SUVR) of WMH and normal-appearing WM (NAWM) were calculated using the inferior cerebellar grey matter as reference region, and a 3-mm erosion was applied to the combined NAWM and WMH masks to avoid partial volume effects. Longitudinal [18F]flortaucipir SUVR changes in NAWM and WMH were estimated using linear mixed models. The percent variance of WM-referenced cortical [18F]flortaucipir SUVRs explained by longitudinal changes in the WM reference region was estimated with the R2 coefficient. RESULTS Compared to NAWM, WMH areas displayed significantly reduced [18F]flortaucipir SUVR, independent of cognitive impairment or Aβ status (mean difference = 0.14 SUVR, p < 0.001). Older age was associated with lower [18F]flortaucipir SUVR in both NAWM (- 0.002 SUVR/year, p = 0.005) and WMH (- 0.004 SUVR/year, p < 0.001). Longitudinally, [18F]flortaucipir SUVR decreased in NAWM (- 0.008 SUVR/year, p = 0.03) and even more so in WMH (- 0.02 SUVR/year, p < 0.001). Between 17% and 66% of the variance of longitudinal changes in cortical WM-referenced [18F]flortaucipir SUVRs were explained by longitudinal changes in the reference region. CONCLUSIONS [18F]flortaucipir retention in the WM decreases over time and is influenced by the presence of WMH, supporting the hypothesis that [18F]flortaucipir retention in the WM is partially myelin-dependent. These findings have implications for the use of WM reference regions for [18F]flortaucipir-PET imaging.
Collapse
|
11
|
Parente A, Maciel ES, J O Dierckx RA, Langendijk JA, de Vries EFJ, Doorduin J. Delayed effects of a single-dose whole-brain radiation therapy on glucose metabolism and myelin density: a longitudinal PET study. Int J Radiat Biol 2020; 96:1135-1143. [PMID: 32602390 DOI: 10.1080/09553002.2020.1787542] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
PURPOSE Radiotherapy is an important treatment option for brain tumors, but the unavoidable irradiation of normal brain tissue can lead to delayed cognitive impairment. The mechanisms involved are still not well explained and, therefore, new tools to investigate the processes leading to the delayed symptoms of brain irradiation are warranted. In this study, positron emission tomography (PET) is used to explore delayed functional changes induced by brain irradiation. MATERIALS AND METHODS Male Wistar rats were subjected to a single 25-Gy dose of whole brain X-ray irradiation, or sham-irradiation. To investigate delayed effects of radiation on cerebral glucose metabolism and myelin density, 18F-fluorodeoxyglucose (18F-FDG) PET scans were performed at baseline and on day 64 and 94, whereas N-11C-methyl-4,4'-diaminostilbene (11C-MeDAS) PET scans were performed at baseline and on day 60 and 90 post-irradiation. In addition, the open field test (OFT) and novel spatial recognition (NSR) test were performed at baseline and on days 59 and 89 to investigate whether whole brain irradiation induces behavioral changes. RESULTS Whole-brain irradiation caused loss of bodyweight and delayed cerebral hypometabolism, with 18F-FDG uptake in all brain regions being significantly decreased in irradiated rat on day 64 while it remained unchanged in control animals. Only amygdala and cortical brain regions of irradiated rats still showed reduced 18F-FDG uptake on day 94. 11C-MeDAS uptake in control animals was significantly lower on days 60 and 90 than at the baseline, suggesting a reduction in myelin density in young adults. In irradiated animals, 11C-MeDAS uptake was similarly reduced on day 60, but on day 90 tracer uptake was somewhat increased and not significantly different from baseline anymore. Behavioral tests showed a similar pattern in control and irradiated animals. In both groups, the OFT showed significantly reduced mobility on days 59 and 89, whereas the NSR did not reveal any significant changes in spatial memory over time. Interestingly, a positive correlation between the NSR and 11C-MeDAS uptake was observed in irradiated rats. CONCLUSIONS Whole-brain irradiation causes delayed brain hypometabolism, which is not accompanied by white matter loss. Irradiated animals showed similar behavioral changes over time as control animals and, therefore, cerebral hypometabolism could not be linked to behavioral abnormalities. However, spatial memory seems to be associated with myelin density in irradiated rats.
Collapse
Affiliation(s)
- Andrea Parente
- Department of Nuclear Medicine and Molecular Imaging, Medical Imaging Center, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Elisa Scandiuzzi Maciel
- Department of Nuclear Medicine and Molecular Imaging, Medical Imaging Center, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Rudi A J O Dierckx
- Department of Nuclear Medicine and Molecular Imaging, Medical Imaging Center, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Johannes A Langendijk
- Department of Radiation Oncology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Erik F J de Vries
- Department of Nuclear Medicine and Molecular Imaging, Medical Imaging Center, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Janine Doorduin
- Department of Nuclear Medicine and Molecular Imaging, Medical Imaging Center, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| |
Collapse
|
12
|
|
13
|
de Paula Faria D. Myelin positron emission tomography (PET) imaging in multiple sclerosis. Neural Regen Res 2020; 15:1842-1843. [PMID: 32246627 PMCID: PMC7513961 DOI: 10.4103/1673-5374.280311] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
|
14
|
Zhang M, Liu J, Li B, Chen S. 18F-florbetapir PET/MRI for quantitatively monitoring demyelination and remyelination in acute disseminated encephalomyelitis. EJNMMI Res 2019; 9:96. [PMID: 31720882 PMCID: PMC6851275 DOI: 10.1186/s13550-019-0568-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2019] [Accepted: 10/16/2019] [Indexed: 01/31/2023] Open
Affiliation(s)
- Min Zhang
- Department of Nuclear Medicine, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jun Liu
- Department of Neurology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, 197 Ruijin 2nd Road, Shanghai, 200025, China
| | - Biao Li
- Department of Nuclear Medicine, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Sheng Chen
- Department of Neurology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, 197 Ruijin 2nd Road, Shanghai, 200025, China.
| |
Collapse
|
15
|
Carvalho RH, Real CC, Cinini S, Garcez AT, Duran FL, Marques FL, Mello LE, Busatto Filho G, de Vries EF, de Britto LR, Buchpiguel CA, de Paula Faria D. [11C]PIB PET imaging can detect white and grey matter demyelination in a non-human primate model of progressive multiple sclerosis. Mult Scler Relat Disord 2019; 35:108-115. [DOI: 10.1016/j.msard.2019.07.020] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Revised: 07/08/2019] [Accepted: 07/23/2019] [Indexed: 11/29/2022]
|
16
|
Evaluation of Myelin Radiotracers in the Lysolecithin Rat Model of Focal Demyelination: Beware of Pitfalls! CONTRAST MEDIA & MOLECULAR IMAGING 2019; 2019:9294586. [PMID: 31281236 PMCID: PMC6594279 DOI: 10.1155/2019/9294586] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Revised: 02/06/2019] [Accepted: 02/21/2019] [Indexed: 11/29/2022]
Abstract
The observation that amyloid radiotracers developed for Alzheimer's disease bind to cerebral white matter paved the road to nuclear imaging of myelin in multiple sclerosis. The lysolecithin (lysophosphatidylcholine (LPC)) rat model of demyelination proved useful in evaluating and comparing candidate radiotracers to target myelin. Focal demyelination following stereotaxic LPC injection is larger than lesions observed in experimental autoimmune encephalitis models and is followed by spontaneous progressive remyelination. Moreover, the contralateral hemisphere may serve as an internal control in a given animal. However, demyelination can be accompanied by concurrent focal necrosis and/or adjacent ventricle dilation. The influence of these side effects on imaging findings has never been carefully assessed. The present study describes an optimization of the LPC model and highlights the use of MRI for controlling the variability and pitfalls of the model. The prototypical amyloid radiotracer [11C]PIB was used to show that in vivo PET does not provide sufficient sensitivity to reliably track myelin changes and may be sensitive to LPC side effects instead of demyelination as such. Ex vivo autoradiography with a fluorine radiotracer should be preferred, to adequately evaluate and compare radiotracers for the assessment of myelin content.
Collapse
|
17
|
Tiwari AD, Zhu J, You J, Eck B, Zhu J, Wang X, Wang X, Wang B, Silver J, Wilson D, Wu C, Wang Y. Novel 18F-Labeled Radioligands for Positron Emission Tomography Imaging of Myelination in the Central Nervous System. J Med Chem 2019; 62:4902-4914. [PMID: 31042384 DOI: 10.1021/acs.jmedchem.8b01354] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Myelin is the protective sheath that surrounds nerves in vertebrates to protect axons, which thereby facilitates impulse conduction. Damage to myelin is associated with many neurodegenerative diseases such as multiple sclerosis and also includes spinal cord injury (SCI). The small size of the spinal cord poses formidable challenges to in vivo monitoring of myelination, which we investigated via conducting a structure-activity relationship study to determine the optimum positron-emitting agent to use for imaging myelin using positron emission tomography (PET). From these studies, [18F]PENDAS was identified as the lead agent to use in conjunction with PET imaging to delineate the integrity of spinal cord myelin. A subsequent in vivo PET imaging study of [18F]PENDAS in rats with SCI showed promising pharmacokinetic results that justify further development of imaging markers for diagnosing myelin-related diseases. Additionally, [18F]PENDAS could be valuable in determining the efficacy of therapies that are currently under development.
Collapse
Affiliation(s)
| | | | | | | | | | - Xu Wang
- Department of Radiology , Binzhou Medical University , Binzhou , Shandong 256603 , China
| | - Xizhen Wang
- Department of Radiology , Weifang Medical University , Weifang , Shandong 261053 , China
| | - Bin Wang
- Department of Radiology , Binzhou Medical University , Binzhou , Shandong 256603 , China
| | | | | | | | - Yanming Wang
- Department of Radiology , Binzhou Medical University , Binzhou , Shandong 256603 , China
| |
Collapse
|
18
|
Bauckneht M, Capitanio S, Raffa S, Roccatagliata L, Pardini M, Lapucci C, Marini C, Sambuceti G, Inglese M, Gallo P, Cecchin D, Nobili F, Morbelli S. Molecular imaging of multiple sclerosis: from the clinical demand to novel radiotracers. EJNMMI Radiopharm Chem 2019; 4:6. [PMID: 31659498 PMCID: PMC6453990 DOI: 10.1186/s41181-019-0058-3] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Accepted: 03/21/2019] [Indexed: 12/13/2022] Open
Abstract
Background Brain PET imaging with different tracers is mainly clinically used in the field of neurodegenerative diseases and brain tumors. In recent years, the potential usefulness of PET has also gained attention in the field of MS. In fact, MS is a complex disease and several processes can be selected as a target for PET imaging. The use of PET with several different tracers has been mainly evaluated in the research setting to investigate disease pathophysiology (i.e. phenotypes, monitoring of progression) or to explore its use a surrogate end-point in clinical trials. Results We have reviewed PET imaging studies in MS in humans and animal models. Tracers have been grouped according to their pathophysiological targets (ie. tracers for myelin kinetic, neuroinflammation, and neurodegeneration). The emerging clinical indication for brain PET imaging in the differential diagnosis of suspected tumefactive demyelinated plaques as well as the clinical potential provided by PET images in view of the recent introduction of PET/MR technology are also addressed. Conclusion While several preclinical and fewer clinical studies have shown results, full-scale clinical development programs are needed to translate molecular imaging technologies into a clinical reality that could ideally fit into current precision medicine perspectives.
Collapse
Affiliation(s)
- Matteo Bauckneht
- Nuclear Medicine Unit, IRCCS Ospedale Policlinico San Martino, Largo R. Benzi 10, 16132, Genoa, Italy.
| | - Selene Capitanio
- Nuclear Medicine Unit, IRCCS Ospedale Policlinico San Martino, Largo R. Benzi 10, 16132, Genoa, Italy
| | - Stefano Raffa
- Department of Health Sciences (DISSAL), University of Genova, Genoa, Italy
| | - Luca Roccatagliata
- Department of Health Sciences (DISSAL), University of Genova, Genoa, Italy.,Neuroradiology, IRCCS Ospedale Policlinico San Martino, Genoa, Italy
| | - Matteo Pardini
- Clinical Neurology, Department of Neuroscience (DINOGMI), University of Genoa, Genoa, Italy.,Clinica Neurologica, IRCCS Ospedale Policlinico, San Martino, Genoa, Italy
| | - Caterina Lapucci
- Clinical Neurology, Department of Neuroscience (DINOGMI), University of Genoa, Genoa, Italy
| | - Cecilia Marini
- Nuclear Medicine Unit, IRCCS Ospedale Policlinico San Martino, Largo R. Benzi 10, 16132, Genoa, Italy.,CNR Institute of Molecular Bioimaging and Physiology, Milan, Italy
| | - Gianmario Sambuceti
- Nuclear Medicine Unit, IRCCS Ospedale Policlinico San Martino, Largo R. Benzi 10, 16132, Genoa, Italy.,Department of Health Sciences (DISSAL), University of Genova, Genoa, Italy
| | - Matilde Inglese
- Clinical Neurology, Department of Neuroscience (DINOGMI), University of Genoa, Genoa, Italy.,Clinica Neurologica, IRCCS Ospedale Policlinico, San Martino, Genoa, Italy
| | - Paolo Gallo
- Multiple Sclerosis Centre of the Veneto Region, Department of Neurosciences DNS, University of Padua, Padua, Italy
| | - Diego Cecchin
- Nuclear Medicine Unit, Department of Medicine-DIMED, Padova University Hospital, Padua, Italy.,Padua Neuroscience Center, University of Padua, Padua, Italy
| | - Flavio Nobili
- Clinical Neurology, Department of Neuroscience (DINOGMI), University of Genoa, Genoa, Italy.,Clinica Neurologica, IRCCS Ospedale Policlinico, San Martino, Genoa, Italy
| | - Silvia Morbelli
- Nuclear Medicine Unit, IRCCS Ospedale Policlinico San Martino, Largo R. Benzi 10, 16132, Genoa, Italy.,Department of Health Sciences (DISSAL), University of Genova, Genoa, Italy
| |
Collapse
|
19
|
Zeydan B, Schwarz CG, Lowe VJ, Reid RI, Przybelski SA, Lesnick TG, Kremers WK, Senjem ML, Gunter JL, Min H, Vemuri P, Knopman DS, Petersen RC, Jack CR, Kantarci OH, Kantarci K. Investigation of white matter PiB uptake as a marker of white matter integrity. Ann Clin Transl Neurol 2019; 6:678-688. [PMID: 31019992 PMCID: PMC6469255 DOI: 10.1002/acn3.741] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Revised: 01/14/2019] [Accepted: 02/03/2019] [Indexed: 01/20/2023] Open
Abstract
OBJECTIVE To investigate the associations of Pittsburgh compound-B (PiB) uptake in white matter hyperintensities (WMH) and normal appearing white matter (NAWM) with white matter (WM) integrity measured with DTI and cognitive function in cognitively unimpaired older adults. METHODS Cognitively unimpaired older adults from the population-based Mayo Clinic Study of Aging (n = 537, age 65-95) who underwent both PiB PET and DTI were included. The associations of WM PiB standard uptake value ratio (SUVr) with fractional anisotropy (FA) and mean diffusivity (MD) in the WMH and NAWM were tested after adjusting for age. The associations of PiB SUVr with cognitive function z-scores were tested after adjusting for age and global cortical PiB SUVr. RESULTS The WMH PiB SUVr was lower than NAWM PiB SUVr (P < 0.001). In the WMH, lower PiB SUVr correlated with lower FA (r = 0.21, P < 0.001), and higher MD (r = -0.31, P < 0.001). In the NAWM, lower PiB SUVr only correlated with higher MD (r = -0.10, P = 0.02). Both in the WMH and NAWM, lower PiB SUVr was associated with lower memory, language, and global cognitive function z-scores after adjusting for age and global cortical PiB SUVr. INTERPRETATION Reduced PiB uptake in the WMH is associated with a loss of WM integrity and cognitive function after accounting for the global cortical PiB uptake, suggesting that WM PiB uptake may be an early biomarker of WM integrity that precedes cognitive impairment in older adults. When using WM as a reference region in cross-sectional analysis of PiB SUVr, individual variability in WMH volume as well as age should be considered.
Collapse
Affiliation(s)
- Burcu Zeydan
- Department of RadiologyMayo ClinicRochesterMinnesota
- Department of NeurologyMayo ClinicRochesterMinnesota
- Center for Multiple Sclerosis and Autoimmune NeurologyMayo ClinicRochesterMinnesota
| | | | - Val J. Lowe
- Department of RadiologyMayo ClinicRochesterMinnesota
| | - Robert I. Reid
- Department of Information TechnologyMayo ClinicRochesterMinnesota
| | | | | | | | - Matthew L. Senjem
- Department of RadiologyMayo ClinicRochesterMinnesota
- Department of Information TechnologyMayo ClinicRochesterMinnesota
| | - Jeffrey L. Gunter
- Department of RadiologyMayo ClinicRochesterMinnesota
- Department of Information TechnologyMayo ClinicRochesterMinnesota
| | - Hoon‐Ki Min
- Department of RadiologyMayo ClinicRochesterMinnesota
| | | | | | | | | | - Orhun H. Kantarci
- Department of NeurologyMayo ClinicRochesterMinnesota
- Center for Multiple Sclerosis and Autoimmune NeurologyMayo ClinicRochesterMinnesota
| | | |
Collapse
|
20
|
Kopec BM, Ulapane KR, Moral MEG, Siahaan TJ. Methods of Delivering Molecules Through the Blood-Brain Barrier for Brain Diagnostics and Therapeutics. BLOOD-BRAIN BARRIER 2019. [DOI: 10.1007/978-1-4939-8946-1_2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
|
21
|
Morbelli S, Bauckneht M, Capitanio S, Pardini M, Roccatagliata L, Nobili F. A new frontier for amyloid PET imaging: multiple sclerosis. Eur J Nucl Med Mol Imaging 2018; 46:276-279. [DOI: 10.1007/s00259-018-4232-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2018] [Accepted: 11/27/2018] [Indexed: 12/29/2022]
|
22
|
Stankoff B, Poirion E, Tonietto M, Bodini B. Exploring the heterogeneity of MS lesions using positron emission tomography: a reappraisal of their contribution to disability. Brain Pathol 2018; 28:723-734. [PMID: 30020560 PMCID: PMC8099240 DOI: 10.1111/bpa.12641] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2018] [Accepted: 07/09/2018] [Indexed: 12/22/2022] Open
Abstract
The biological mechanisms driving disability worsening in multiple sclerosis (MS) are only partly understood. Monitoring changes in lesion load on MRI has a limited predictive value on the progression of clinical disability, and there is an essential need for novel imaging markers specific for the main candidate mechanisms underlying neurodegeneration which include failing myelin repair, innate immune cell activation and gray matter neuronal damage. Positron Emission Tomography (PET) is an imaging technology based on the injection of radiotracers directed against specific molecular targets, which has recently allowed the selective quantification in-vivo of the key biological mechanisms relevant to MS pathophysiology. Pilot PET studies performed in patients with all forms of MS allowed to revisit the contribution of MS lesions to disability worsening and showed that the evolution of lesions toward chronic activation, together with their remyelination profile were relevant predictors of disability worsening. PET offers the opportunity to bridge a critical gap between neuropathology and in-vivo imaging. This technique provides an original approach to disentangle some of the most relevant pathological components driving MS progression, to follow-up their temporal evolution, to investigate their clinical relevance and to evaluate novel therapeutics aimed to prevent disease progression.
Collapse
Affiliation(s)
- Bruno Stankoff
- Sorbonne UniversitésUPMC Paris 06Institut du Cerveau et de la Moelle épinièreICMHôpital de la Pitié SalpêtrièreInserm UMR S 1127CNRS UMR 7225ParisFrance
- AP‐HPHôpital Saint‐AntoineParisFrance
| | - Emilie Poirion
- Sorbonne UniversitésUPMC Paris 06Institut du Cerveau et de la Moelle épinièreICMHôpital de la Pitié SalpêtrièreInserm UMR S 1127CNRS UMR 7225ParisFrance
| | - Matteo Tonietto
- Sorbonne UniversitésUPMC Paris 06Institut du Cerveau et de la Moelle épinièreICMHôpital de la Pitié SalpêtrièreInserm UMR S 1127CNRS UMR 7225ParisFrance
| | - Benedetta Bodini
- Sorbonne UniversitésUPMC Paris 06Institut du Cerveau et de la Moelle épinièreICMHôpital de la Pitié SalpêtrièreInserm UMR S 1127CNRS UMR 7225ParisFrance
- AP‐HPHôpital Saint‐AntoineParisFrance
| |
Collapse
|
23
|
Högel H, Rissanen E, Vuorimaa A, Airas L. Positron emission tomography imaging in evaluation of MS pathology in vivo. Mult Scler 2018; 24:1399-1412. [DOI: 10.1177/1352458518791680] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Positron emission tomography (PET) gives an opportunity to quantitate the expression of specific molecular targets in vivo and longitudinally in brain and thus enhances our possibilities to understand and follow up multiple sclerosis (MS)-related pathology. For successful PET imaging, one needs a relevant target molecule within the brain, to which a blood–brain barrier–penetrating specific radioligand will bind. 18-kDa translocator protein (TSPO)-binding radioligands have been used to detect activated microglial cells at different stages of MS, and remyelination has been measured using amyloid PET. Several PET ligands for the detection of other inflammatory targets, besides TSPO, have been developed but not yet been used for imaging MS patients. Finally, synaptic density evaluation has been successfully tested in human subjects and gives opportunities for the evaluation of the development of cortical and deep gray matter pathology in MS. This review will discuss PET imaging modalities relevant for MS today.
Collapse
Affiliation(s)
- Heidi Högel
- Turku PET Centre, Turku University Hospital and University of Turku, Turku, Finland/Division of Clinical Neurosciences, Turku University Hospital and University of Turku, Turku, Finland
| | - Eero Rissanen
- Turku PET Centre, Turku University Hospital and University of Turku, Turku, Finland/Division of Clinical Neurosciences, Turku University Hospital and University of Turku, Turku, Finland
| | - Anna Vuorimaa
- Turku PET Centre, Turku University Hospital and University of Turku, Turku, Finland/Division of Clinical Neurosciences, Turku University Hospital and University of Turku, Turku, Finland
| | - Laura Airas
- Turku PET Centre, Turku University Hospital and University of Turku, Turku, Finland/Division of Clinical Neurosciences, Turku University Hospital and University of Turku, Turku, Finland
| |
Collapse
|
24
|
Zeydan B, Lowe VJ, Schwarz CG, Przybelski SA, Tosakulwong N, Zuk SM, Senjem ML, Gunter JL, Roberts RO, Mielke MM, Benarroch EE, Rodriguez M, Machulda MM, Lesnick TG, Knopman DS, Petersen RC, Jack CR, Kantarci K, Kantarci OH. Pittsburgh compound-B PET white matter imaging and cognitive function in late multiple sclerosis. Mult Scler 2018; 24:739-749. [PMID: 28474977 PMCID: PMC5665724 DOI: 10.1177/1352458517707346] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
BACKGROUND There is growing interest in white matter (WM) imaging with positron emission tomography (PET). OBJECTIVES We studied the association of cognitive function in late multiple sclerosis (MS) with cortical and WM Pittsburgh compound-B PET (PiB-PET) binding. METHODS In the population-based Mayo Clinic Study of Aging, 24 of 4869 participants had MS (12 underwent PiB-PET). Controls were age and sex matched (5:1). We used automated or semi-automated processing for quantitative image analyses and conditional logistic regression for group differences. RESULTS MS patients had lower memory ( p = 0.03) and language ( p = 0.02) performance; smaller thalamic volumes ( p = 0.003); and thinner temporal ( p = 0.001) and frontal ( p = 0.045) cortices on magnetic resonance imaging (MRI) than controls. There was no difference in global cortical PiB standardized uptake value ratios between MS and controls ( p = 0.35). PiB uptake was lower in areas of WM hyperintensities compared to normal-appearing white matter (NAWM) in MS ( p = 0.0002). Reduced PiB uptake in both the areas of WM hyperintensities ( r = 0.65; p = 0.02) and NAWM ( r = 0.69; p = 0.01) was associated with decreased visuospatial performance in MS. CONCLUSION PiB uptake in the cortex in late MS is not different from normal age-matched controls. PiB uptake in the WM in late MS may be a marker of the large network structures' integrity such as those involved in visuospatial performance.
Collapse
Affiliation(s)
- Burcu Zeydan
- Mayo Clinic College of Medicine, Department of Neurology, Rochester, Minnesota, United States of America
- Mayo Clinic College of Medicine, Department of Radiology, Rochester, Minnesota, United States of America
| | - Val J. Lowe
- Mayo Clinic College of Medicine, Department of Radiology, Rochester, Minnesota, United States of America
| | - Christopher G. Schwarz
- Mayo Clinic College of Medicine, Department of Radiology, Rochester, Minnesota, United States of America
| | - Scott A. Przybelski
- Mayo Clinic College of Medicine, Department of Health Sciences Research, Rochester, Minnesota, United States of America
| | - Nirubol Tosakulwong
- Mayo Clinic College of Medicine, Department of Health Sciences Research, Rochester, Minnesota, United States of America
| | - Samantha M. Zuk
- Mayo Clinic College of Medicine, Department of Radiology, Rochester, Minnesota, United States of America
| | - Matthew L. Senjem
- Mayo Clinic College of Medicine, Department of Radiology, Rochester, Minnesota, United States of America
- Mayo Clinic College of Medicine, Department of Information Technology, Rochester, Minnesota, United States of America
| | - Jeffrey L. Gunter
- Mayo Clinic College of Medicine, Department of Information Technology, Rochester, Minnesota, United States of America
| | - Rosebud O. Roberts
- Mayo Clinic College of Medicine, Department of Neurology, Rochester, Minnesota, United States of America
- Mayo Clinic College of Medicine, Department of Health Sciences Research, Rochester, Minnesota, United States of America
| | - Michelle M. Mielke
- Mayo Clinic College of Medicine, Department of Neurology, Rochester, Minnesota, United States of America
- Mayo Clinic College of Medicine, Department of Health Sciences Research, Rochester, Minnesota, United States of America
| | - Eduardo E. Benarroch
- Mayo Clinic College of Medicine, Department of Neurology, Rochester, Minnesota, United States of America
| | - Moses Rodriguez
- Mayo Clinic College of Medicine, Department of Neurology, Rochester, Minnesota, United States of America
| | - Mary M. Machulda
- Mayo Clinic College of Medicine, Department of Psychiatry and Psychology, Rochester, Minnesota, United States of America
| | - Timothy G. Lesnick
- Mayo Clinic College of Medicine, Department of Health Sciences Research, Rochester, Minnesota, United States of America
| | - David S. Knopman
- Mayo Clinic College of Medicine, Department of Neurology, Rochester, Minnesota, United States of America
| | - Ronald C. Petersen
- Mayo Clinic College of Medicine, Department of Neurology, Rochester, Minnesota, United States of America
| | - Clifford R. Jack
- Mayo Clinic College of Medicine, Department of Radiology, Rochester, Minnesota, United States of America
| | - Kejal Kantarci
- Mayo Clinic College of Medicine, Department of Radiology, Rochester, Minnesota, United States of America
| | - Orhun H. Kantarci
- Mayo Clinic College of Medicine, Department of Neurology, Rochester, Minnesota, United States of America
| |
Collapse
|
25
|
Abstract
PURPOSE OF REVIEW Despite major progress in multiple sclerosis (MS) treatment, to date, accumulation of irreversible clinical disability is not sufficiently prevented with immunotherapies. In this context, repair strategies aimed at reducing axonal damage are becoming a very active field of preclinical and clinical research. RECENT FINDINGS Improved understanding of the cellular and molecular mechanisms of myelin repair, together with the emergence of new therapeutic candidates are paving the way for novel therapeutic strategies in MS. In parallel, there is a very active development of imaging methods to assess lesions ongoing remyelination that are crucially needed to evaluate therapeutic efficacy. SUMMARY The current development of a very dynamic and multidisciplinary research on remyelination should accelerate the development of myelin repair strategies in MS, to prevent disability progression.
Collapse
|
26
|
Bodini B, Stankoff B. Imaging Central Nervous System Demyelination and Remyelination by Positron-Emission Tomography. Brain Plast 2016; 2:93-98. [PMID: 29765850 PMCID: PMC5928544 DOI: 10.3233/bpl-160042] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Positron Emission Tomography (PET), an imaging technique based on the injection of radiotracers directed against specific biological targets within brain tissues, within brain tissues, is a specific and sensitive technique which offers the unique opportunity to quantify myelin dynamics in the central nervous system. Several stilbene and benzothiazole derivatives have been repurposed to image myelin by PET. In demyelinating and dysmyelinating models, selected radiotracers were shown to reliably quantify demyelination and remyelination, allowing a translational approach in humans. A pilot study in subjects with active relapsing MS using PET and the most available benzothiazole derivative, [11C]PIB, supported the hypothesis that this technique is able to quantify myelin content in multiple sclerosis (MS) lesions and to capture dynamic demyelination and remyelination over time. This study highlighted for the first time in vivo the prognostic value of individual profiles of remyelination on the disease course. In future, the clinical application of myelin PET will be pushed forward thanks to the availability of novel fluorinated tracers for myelin, together with the setting up of non invasive quantification procedures and the use of powerful PET-MR systems. This will enable to address in vivo critical unanswered questions about the pathogenesis of remyelination, and to measure the efficacy of emerging promyelinating drugs in early-phase therapeutic trials.
Collapse
Affiliation(s)
- Benedetta Bodini
- Sorbonne Université, UPMC Paris 06, Institut du Cerveau et de la Moelle épiniére, ICM, Hôpital de la Pitié Salpêtriére, Inserm UMR S 1127, CNRS UMR 7225, Paris, France.,APHP, Assistance Publique des Hôpitaux de Paris, Hôpitaux Saint Antoine and Pitié-Salpêtriére, Paris, France
| | - Bruno Stankoff
- Sorbonne Université, UPMC Paris 06, Institut du Cerveau et de la Moelle épiniére, ICM, Hôpital de la Pitié Salpêtriére, Inserm UMR S 1127, CNRS UMR 7225, Paris, France.,APHP, Assistance Publique des Hôpitaux de Paris, Hôpitaux Saint Antoine and Pitié-Salpêtriére, Paris, France
| |
Collapse
|
27
|
Matías-Guiu J, Gomez-Pinedo U, Matias-Guiu JA. News in multiple sclerosis: Remyelination as a therapeutic target. Med Clin (Barc) 2016; 148:377-380. [PMID: 27923464 DOI: 10.1016/j.medcli.2016.10.021] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Revised: 10/19/2016] [Accepted: 10/21/2016] [Indexed: 01/26/2023]
Affiliation(s)
- Jorge Matías-Guiu
- Servicio de Neurología, Instituto de Neurociencias, Hospital Clínico San Carlos, Universidad Complutense, Instituto de Investigación Sanitaria San Carlos (idiSSC), Madrid, España.
| | - Ulises Gomez-Pinedo
- Servicio de Neurología, Instituto de Neurociencias, Hospital Clínico San Carlos, Universidad Complutense, Instituto de Investigación Sanitaria San Carlos (idiSSC), Madrid, España
| | - Jordi A Matias-Guiu
- Servicio de Neurología, Instituto de Neurociencias, Hospital Clínico San Carlos, Universidad Complutense, Instituto de Investigación Sanitaria San Carlos (idiSSC), Madrid, España
| |
Collapse
|
28
|
Poutiainen P, Jaronen M, Quintana FJ, Brownell AL. Precision Medicine in Multiple Sclerosis: Future of PET Imaging of Inflammation and Reactive Astrocytes. Front Mol Neurosci 2016; 9:85. [PMID: 27695400 PMCID: PMC5023680 DOI: 10.3389/fnmol.2016.00085] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2016] [Accepted: 08/30/2016] [Indexed: 12/29/2022] Open
Abstract
Non-invasive molecular imaging techniques can enhance diagnosis to achieve successful treatment, as well as reveal underlying pathogenic mechanisms in disorders such as multiple sclerosis (MS). The cooperation of advanced multimodal imaging techniques and increased knowledge of the MS disease mechanism allows both monitoring of neuronal network and therapeutic outcome as well as the tools to discover novel therapeutic targets. Diverse imaging modalities provide reliable diagnostic and prognostic platforms to better achieve precision medicine. Traditionally, magnetic resonance imaging (MRI) has been considered the golden standard in MS research and diagnosis. However, positron emission tomography (PET) imaging can provide functional information of molecular biology in detail even prior to anatomic changes, allowing close follow up of disease progression and treatment response. The recent findings support three major neuroinflammation components in MS: astrogliosis, cytokine elevation, and significant changes in specific proteins, which offer a great variety of specific targets for imaging purposes. Regardless of the fact that imaging of astrocyte function is still a young field and in need for development of suitable imaging ligands, recent studies have shown that inflammation and astrocyte activation are related to progression of MS. MS is a complex disease, which requires understanding of disease mechanisms for successful treatment. PET is a precise non-invasive imaging method for biochemical functions and has potential to enhance early and accurate diagnosis for precision therapy of MS. In this review we focus on modulation of different receptor systems and inflammatory aspect of MS, especially on activation of glial cells, and summarize the recent findings of PET imaging in MS and present the most potent targets for new biomarkers with the main focus on experimental MS research.
Collapse
Affiliation(s)
- Pekka Poutiainen
- Athinoula A Martinos Biomedical Imaging Center, Department of Radiology, Massachusetts General Hospital, Harvard Medical SchoolCharlestown, MA, USA
| | - Merja Jaronen
- Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital, Harvard Medical SchoolBoston, MA, USA
| | - Francisco J. Quintana
- Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital, Harvard Medical SchoolBoston, MA, USA
| | - Anna-Liisa Brownell
- Athinoula A Martinos Biomedical Imaging Center, Department of Radiology, Massachusetts General Hospital, Harvard Medical SchoolCharlestown, MA, USA
| |
Collapse
|
29
|
Huang SL, Chang CW, Lee YH, Yang FY. Protective Effect of Low-Intensity Pulsed Ultrasound on Memory Impairment and Brain Damage in a Rat Model of Vascular Dementia. Radiology 2016; 282:113-122. [PMID: 27399328 DOI: 10.1148/radiol.2016160095] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Purpose To investigate the neuroprotective effects of low-intensity pulsed (LIP) ultrasound on memory impairment and central nervous system injury in a rat model of vascular dementia. Materials and Methods All animal experiments were approved by the animal care and use committee and adhered to experimental animal care guidelines. A 1.0-MHz focused ultrasound transducer was used to stimulate the brain noninvasively with 50-msec bursts at a 5% duty cycle, repetition frequency of 1 Hz, and spatial peak temporal average intensity of 528 mW/cm2. LIP ultrasound treatment was performed daily with triple sonications in each hemisphere. The duration of each sonicaton was 5 minutes, with a 5-minute interval between each sonication. Permanent bilateral common carotid artery occlusion (BCCAO) was used as a model of vascular dementia. After 2 weeks of LIP ultrasound, neuroprotective effects of LIP ultrasound were evaluated with behavioral analysis, including the passive avoidance task and elevated plus maze. Myelin content was detected with carbon 11 (11C) Pittsburgh compound B (PIB). Brain sections were stained with hematoxylin-eosin and Luxol fast blue. Two-way analysis of variance and Student t test were used for statistical analyses, with a significance level of .05. Results Protein expressions of brain-derived neurotrophic factor (BDNF) in the BCCAO rats treated with LIP ultrasound were significantly higher than those in BCCAO rats (1.1 ± 0.0 vs 0.8 ± 0.1, P < .05). BCCAO rats exhibited neuronal damage and demyelination. Compared with the BCCAO group, 11C PIB accumulation in the BCCAO rats treated with LIP ultrasound was significantly (P < .05) increased by 67.4% and 203.0% in the hippocampus and corpus callosum, respectively. Hematoxylin-eosin staining showed that neuronal injury in the hippocampal cornu ammonis 1 region was alleviated with LIP ultrasound. Luxol fast blue staining of the corpus callosum was significantly greater in the BCCAO rats treated with LIP ultrasound than in the untreated BCCAO rats (mean, 94.5% ± 2.3 [standard error] vs 86.6% ± 1.0; P < .05). Moreover, LIP ultrasound stimulation significantly improved learning and memory abilities and morphology in rats with vascular dementia compared with rats with untreated vascular dementia (P < .05). Conclusion These results suggest LIP ultrasound stimulation protects against brain injury in the hippocampus and corpus callosum in rats with vascular dementia. The beneficial effect of LIP ultrasound may be partly induced by upregulation of protein expression of BDNF. © RSNA, 2016.
Collapse
Affiliation(s)
- Sin-Luo Huang
- From the Department of Biomedical Imaging and Radiological Sciences (S.L.H., C.W.C., F.Y.Y.), Department and Institute of Physiology (Y.H.L.), Biophotonics and Molecular Imaging Research Center (F.Y.Y.), and Biomedical Engineering Research and Development Center (F.Y.Y.), National Yang-Ming University, Number 155, Section 2, Li-Nong St, Taipei, Taiwan; and National PET/Cyclotron Center, Taipei Veterans General Hospital, Taipei, Taiwan (C.W.C.)
| | - Chi-Wei Chang
- From the Department of Biomedical Imaging and Radiological Sciences (S.L.H., C.W.C., F.Y.Y.), Department and Institute of Physiology (Y.H.L.), Biophotonics and Molecular Imaging Research Center (F.Y.Y.), and Biomedical Engineering Research and Development Center (F.Y.Y.), National Yang-Ming University, Number 155, Section 2, Li-Nong St, Taipei, Taiwan; and National PET/Cyclotron Center, Taipei Veterans General Hospital, Taipei, Taiwan (C.W.C.)
| | - Yi-Hsuan Lee
- From the Department of Biomedical Imaging and Radiological Sciences (S.L.H., C.W.C., F.Y.Y.), Department and Institute of Physiology (Y.H.L.), Biophotonics and Molecular Imaging Research Center (F.Y.Y.), and Biomedical Engineering Research and Development Center (F.Y.Y.), National Yang-Ming University, Number 155, Section 2, Li-Nong St, Taipei, Taiwan; and National PET/Cyclotron Center, Taipei Veterans General Hospital, Taipei, Taiwan (C.W.C.)
| | - Feng-Yi Yang
- From the Department of Biomedical Imaging and Radiological Sciences (S.L.H., C.W.C., F.Y.Y.), Department and Institute of Physiology (Y.H.L.), Biophotonics and Molecular Imaging Research Center (F.Y.Y.), and Biomedical Engineering Research and Development Center (F.Y.Y.), National Yang-Ming University, Number 155, Section 2, Li-Nong St, Taipei, Taiwan; and National PET/Cyclotron Center, Taipei Veterans General Hospital, Taipei, Taiwan (C.W.C.)
| |
Collapse
|
30
|
Bodini B, Veronese M, García‐Lorenzo D, Battaglini M, Poirion E, Chardain A, Freeman L, Louapre C, Tchikviladze M, Papeix C, Dollé F, Zalc B, Lubetzki C, Bottlaender M, Turkheimer F, Stankoff B. Dynamic Imaging of Individual Remyelination Profiles in Multiple Sclerosis. Ann Neurol 2016; 79:726-738. [PMID: 26891452 PMCID: PMC5006855 DOI: 10.1002/ana.24620] [Citation(s) in RCA: 142] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Revised: 01/25/2016] [Accepted: 02/03/2016] [Indexed: 12/12/2022]
Abstract
Background Quantitative in vivo imaging of myelin loss and repair in patients with multiple sclerosis (MS) is essential to understand the pathogenesis of the disease and to evaluate promyelinating therapies. Selectively binding myelin in the central nervous system white matter, Pittsburgh compound B ([11C]PiB) can be used as a positron emission tomography (PET) tracer to explore myelin dynamics in MS. Methods Patients with active relapsing‐remitting MS (n = 20) and healthy controls (n = 8) were included in a longitudinal trial combining PET with [11C]PiB and magnetic resonance imaging. Voxel‐wise maps of [11C]PiB distribution volume ratio, reflecting myelin content, were derived. Three dynamic indices were calculated for each patient: the global index of myelin content change; the index of demyelination; and the index of remyelination. Results At baseline, there was a progressive reduction in [11C]PiB binding from the normal‐appearing white matter to MS lesions, reflecting a decline in myelin content. White matter lesions were characterized by a centripetal decrease in the tracer binding at the voxel level. During follow‐up, high between‐patient variability was found for all indices of myelin content change. Dynamic remyelination was inversely correlated with clinical disability (p = 0.006 and beta‐coefficient = –0.67 with the Expanded Disability Status Scale; p = 0.003 and beta‐coefficient = –0.68 with the MS Severity Scale), whereas no significant clinical correlation was found for the demyelination index. Interpretation [11C]PiB PET allows quantification of myelin dynamics in MS and enables stratification of patients depending on their individual remyelination potential, which significantly correlates with clinical disability. This technique should be considered to assess novel promyelinating drugs. Ann Neurol 2016;79:726–738
Collapse
Affiliation(s)
- Benedetta Bodini
- Sorbonne UniversitésUPMC University Paris 06UMR S 1127, and CNRS UMR 7225, and ICMF‐75013ParisFrance
- Department of Neuroimaging, Institute of PsychiatryKing's College LondonLondonUnited Kingdom
- Service Hospitalier Fréderic Joliot, SHFJ, I2BM‐DSVCEAOrsayFrance
| | - Mattia Veronese
- Department of Neuroimaging, Institute of PsychiatryKing's College LondonLondonUnited Kingdom
| | - Daniel García‐Lorenzo
- Sorbonne UniversitésUPMC University Paris 06UMR S 1127, and CNRS UMR 7225, and ICMF‐75013ParisFrance
| | - Marco Battaglini
- Department of Behavioral and Neurological SciencesUniversity of SienaSienaItaly
| | - Emilie Poirion
- Sorbonne UniversitésUPMC University Paris 06UMR S 1127, and CNRS UMR 7225, and ICMF‐75013ParisFrance
| | - Audrey Chardain
- Service Hospitalier Fréderic Joliot, SHFJ, I2BM‐DSVCEAOrsayFrance
- APHP Hôpital Saint‐AntoineParisFrance
| | - Léorah Freeman
- Sorbonne UniversitésUPMC University Paris 06UMR S 1127, and CNRS UMR 7225, and ICMF‐75013ParisFrance
- Service Hospitalier Fréderic Joliot, SHFJ, I2BM‐DSVCEAOrsayFrance
- APHPHopital Pitié-SalpetrièreParisFrance
| | - Céline Louapre
- Sorbonne UniversitésUPMC University Paris 06UMR S 1127, and CNRS UMR 7225, and ICMF‐75013ParisFrance
| | | | | | - Frédéric Dollé
- Service Hospitalier Fréderic Joliot, SHFJ, I2BM‐DSVCEAOrsayFrance
| | - Bernard Zalc
- Sorbonne UniversitésUPMC University Paris 06UMR S 1127, and CNRS UMR 7225, and ICMF‐75013ParisFrance
| | - Catherine Lubetzki
- Sorbonne UniversitésUPMC University Paris 06UMR S 1127, and CNRS UMR 7225, and ICMF‐75013ParisFrance
- APHPHopital Pitié-SalpetrièreParisFrance
| | | | - Federico Turkheimer
- Department of Neuroimaging, Institute of PsychiatryKing's College LondonLondonUnited Kingdom
| | - Bruno Stankoff
- Sorbonne UniversitésUPMC University Paris 06UMR S 1127, and CNRS UMR 7225, and ICMF‐75013ParisFrance
- Service Hospitalier Fréderic Joliot, SHFJ, I2BM‐DSVCEAOrsayFrance
- APHP Hôpital Saint‐AntoineParisFrance
| |
Collapse
|
31
|
Tiwari AD, Wu C, Zhu J, Zhang S, Zhu J, Wang WR, Zhang J, Tatsuoka C, Matthews PM, Miller RH, Wang Y. Design, Synthesis, and Evaluation of Fluorinated Radioligands for Myelin Imaging. J Med Chem 2016; 59:3705-18. [PMID: 27070324 DOI: 10.1021/acs.jmedchem.5b01858] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Myelination is one of the fundamental processes in vertebrates. A major challenge is to quantitatively image myelin distribution in the central nervous system. For this reason, we designed and synthesized a series of fluorinated radioligands that can be radiolabeled as radiotracers for positron emission tomography (PET) imaging of myelin. These newly developed radioligands readily penetrate the blood-brain barrier and selectively bind to myelin membranes in the white matter region. Structure-activity relationship studies of such ligands suggested that optimal permeability could be achieved with calculated lipophilicty in the range of 3-4. After radiolabeling with fluorine-18, the brain uptake and retention of each radioligand were determined by microPET/CT imaging studies. These pharmacokinetic studies led us to identify a lead compound ([(18)F]FMeDAS, 32) with promising in vivo binding properties, which was subsequently validated by ex vivo autoradiography.
Collapse
Affiliation(s)
| | | | | | | | | | | | - Jinming Zhang
- Department of Nuclear Medicine, People's Liberation Army (PLA) General Hospital , Beijing 100853, China
| | | | - Paul M Matthews
- Division of Brain Sciences, Department of Medicine, Imperial College London , London SW12 0NN, United Kingdom
| | - Robert H Miller
- Department of Anatomy and Regenerative Biology, George Washington University , Washington, DC 20037, United States
| | | |
Collapse
|
32
|
Quantification of [(11)C]PIB PET for imaging myelin in the human brain: a test-retest reproducibility study in high-resolution research tomography. J Cereb Blood Flow Metab 2015; 35:1771-82. [PMID: 26058700 PMCID: PMC4635232 DOI: 10.1038/jcbfm.2015.120] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/27/2014] [Revised: 04/01/2015] [Accepted: 05/05/2015] [Indexed: 01/12/2023]
Abstract
An accurate in vivo measure of myelin content is essential to deepen our insight into the mechanisms underlying demyelinating and dysmyelinating neurological disorders, and to evaluate the effects of emerging remyelinating treatments. Recently [(11)C]PIB, a positron emission tomography (PET) tracer originally conceived as a beta-amyloid marker, has been shown to be sensitive to myelin changes in preclinical models and humans. In this work, we propose a reference-region methodology for the voxelwise quantification of brain white-matter (WM) binding for [(11)C]PIB. This methodology consists of a supervised procedure for the automatic extraction of a reference region and the application of the Logan graphical method to generate distribution volume ratio (DVR) maps. This approach was assessed on a test-retest group of 10 healthy volunteers using a high-resolution PET tomograph. The [(11)C]PIB PET tracer binding was shown to be up to 23% higher in WM compared with gray matter, depending on the image reconstruction. The DVR estimates were characterized by high reliability (outliers <1%) and reproducibility (intraclass correlation coefficient (ICC) >0.95). [(11)C]PIB parametric maps were also found to be significantly correlated (R(2)>0.50) to mRNA expressions of the most represented proteins in the myelin sheath. On the contrary, no correlation was found between [(11)C]PIB imaging and nonmyelin-associated proteins.
Collapse
|
33
|
Heurling K, Leuzy A, Zimmer ER, Lubberink M, Nordberg A. Imaging β-amyloid using [18F]flutemetamol positron emission tomography: from dosimetry to clinical diagnosis. Eur J Nucl Med Mol Imaging 2015; 43:362-373. [DOI: 10.1007/s00259-015-3208-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Accepted: 09/28/2015] [Indexed: 12/14/2022]
|
34
|
Matthews PM, Datta G. Positron-emission tomography molecular imaging of glia and myelin in drug discovery for multiple sclerosis. Expert Opin Drug Discov 2015; 10:557-70. [PMID: 25843125 DOI: 10.1517/17460441.2015.1032240] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
INTRODUCTION Therapies acting on glial cells are being explored for new drug development for multiple sclerosis. Molecular imaging using positron-emission tomography (PET) could address relevant questions in early phase clinical trials. AREAS COVERED In this article, the authors critically review human PET methods that can be applied in specialised centres for imaging activated microglia and astrocytes and myelin. EXPERT OPINION Strengths of PET lie in the molecular selectivity, sensitivity and potential for absolute quantitation. Even now, translocator protein PET radioligands could be used in exploratory studies for interventions targeting brain microglial activation. The clinical and neuropathological meaningfulness of signal from PET radioligands reporting on astrocyte activation through cellular expression of either monoamine oxidase B or the I2-imidazoline receptor or metabolism of [(11)C]acetate can now explored. [(11)C] N-methyl-4,4'-diaminostilbene, a PET marker for myelin, could soon enter first human trials. However, use of any of these PET glial markers demands a well-focused hypothesis and a commitment to validation in the context of use. Enhanced access to these radioligands, standardisation of analyses and lowering the costs of using them are needed if their full promise is to be realised.
Collapse
Affiliation(s)
- Paul M Matthews
- Imperial College London, Division of Brain Sciences, Department of Medicine , E515, Burlington Danes Building, Du Cane Road, W12 0NN London , UK +44 02075942612 ; +44 02075946548 ;
| | | |
Collapse
|
35
|
Tannahill GM, Iraci N, Gaude E, Frezza C, Pluchino S. Metabolic reprograming of mononuclear phagocytes in progressive multiple sclerosis. Front Immunol 2015; 6:106. [PMID: 25814990 PMCID: PMC4356156 DOI: 10.3389/fimmu.2015.00106] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2015] [Accepted: 02/24/2015] [Indexed: 12/31/2022] Open
Abstract
UNLABELLED Multiple sclerosis (MS) is an inflammatory and demyelinating disease of the central nervous system (CNS). Accumulation of brain damage in progressive MS is partly the result of mononuclear phagocytes (MPs) attacking myelin sheaths in the CNS. Although there is no cure yet for MS, significant advances have been made in the development of disease modifying agents. Unfortunately, most of these drugs fail to reverse established neurological deficits and can have adverse effects. Recent evidence suggests that MPs polarization is accompanied by profound metabolic changes, whereby pro-inflammatory MPs (M1) switch toward glycolysis, whereas anti-inflammatory MPs (M2) become more oxidative. It is therefore possible that reprograming MPs metabolism could affect their function and repress immune cell activation. This mini review describes the metabolic changes underpinning macrophages polarization and anticipates how metabolic re-education of MPs could be used for the treatment of MS. KEY POINTS Inflammation in progressive MS is mediated primarily by MPs.Cell metabolism regulates the function of MPs.DMAs can re-educate the metabolism of MPs to promote healing.
Collapse
Affiliation(s)
- Gillian Margaret Tannahill
- Department of Clinical Neurosciences, NIHR Biomedical Research Centre, University of Cambridge, Cambridge, UK
- Wellcome Trust-Medical Research Council (MRC) Stem Cell Institute, Cambridge, UK
| | - Nunzio Iraci
- Department of Clinical Neurosciences, NIHR Biomedical Research Centre, University of Cambridge, Cambridge, UK
- Wellcome Trust-Medical Research Council (MRC) Stem Cell Institute, Cambridge, UK
| | - Edoardo Gaude
- Wellcome Trust-Medical Research Council (MRC) Stem Cell Institute, Cambridge, UK
- MRC Cancer Unit, Hutchison/MRC Research Centre, University of Cambridge, Cambridge, UK
| | - Christian Frezza
- Wellcome Trust-Medical Research Council (MRC) Stem Cell Institute, Cambridge, UK
- MRC Cancer Unit, Hutchison/MRC Research Centre, University of Cambridge, Cambridge, UK
| | - Stefano Pluchino
- Department of Clinical Neurosciences, NIHR Biomedical Research Centre, University of Cambridge, Cambridge, UK
- Wellcome Trust-Medical Research Council (MRC) Stem Cell Institute, Cambridge, UK
| |
Collapse
|
36
|
Chandra A. Role of amyloid from a multiple sclerosis perspective: a literature review. Neuroimmunomodulation 2015; 22:343-6. [PMID: 25766575 DOI: 10.1159/000375309] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Accepted: 01/16/2015] [Indexed: 11/19/2022] Open
Abstract
The traditional concept of multiple sclerosis (MS), that it is primarily a white matter inflammatory disease, has changed a great deal. Thanks to the recent development witnessed in MS research, a whole new idea has emerged that MS is a neurodegenerative disease, and neurodegeneration occurs rather earlier in the pathological process. This has also led to the foundation of the hypothesis that two fundamentally different diseases, Alzheimer's disease (AD) and MS, may share a common mechanism of neurodegeneration. Conventionally, amyloid is thought to be a consequence of protein misfolding and aggregation and is most notorious for its association with debilitating and chronic human diseases. Amyloid is implicated to be related with the deterioration and progression of AD. The finding of amyloid precursor protein expression in axons around the plaque in MS, as well as the correlation of amyloid-β (Aβ) with different stages of MS, has clearly indicated that amyloid plays some kind of key role in MS disease pathogenesis. Excitingly, a paradoxical phenomenon of Aβ has also been observed in several studies recently. It has been shown that amyloid might actually be helping in ameliorating the inflammatory effect in diseases like AD and MS. Amyloid imaging allows earlier diagnosis of MS by taking advantage of the relation of amyloid with MS. This will have a big impact on patient diagnosis and management. In this review I have included the findings of research studies dating from several years back to the most recent ones. Through this review I have tried to show the critical role of amyloid in MS and the importance of investigating through PET imaging.
Collapse
Affiliation(s)
- Avinash Chandra
- Buffalo Neuroimaging Analysis Center (BNAC), Department of Neurology, Buffalo General Hospital, Buffalo, N.Y., USA
| |
Collapse
|
37
|
Yang FY, Lu WW, Lin WT, Chang CW, Huang SL. Enhancement of Neurotrophic Factors in Astrocyte for Neuroprotective Effects in Brain Disorders Using Low-intensity Pulsed Ultrasound Stimulation. Brain Stimul 2014; 8:465-73. [PMID: 25558041 DOI: 10.1016/j.brs.2014.11.017] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2014] [Revised: 11/27/2014] [Accepted: 11/28/2014] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND Astrocytes play an important role in the growth and survival of developing neurons by secreting neurotrophic factors. OBJECTIVE The goal of this study was to investigate how low-intensity pulsed ultrasound (LIPUS) stimulation directly affects brain astrocyte function. METHODS Here, we report that LIPUS stimulation increased protein levels of BDNF, GDNF, VEGF, and GLUT1 in rat brain astrocytes as measured by western blot analysis. Histological outcomes including demyelination and apoptosis were examined in rats after administration of aluminum chloride (AlCl3). RESULTS At the mechanistic level, integrin inhibitor (RGD peptide) attenuated the LIPUS-induced neurotrophic factor expression. The data suggest that neurotrophic factor protein levels may be promoted by LIPUS through activation of integrin receptor signaling. In addition, LIPUS stimulation protected cells against aluminum toxicity as demonstrated by an increase in the median lethal dose for AlCl3 from 3.77 to 6.25 mM. In in vivo histological evaluations, LIPUS significantly reduced cerebral damages in terms of myelin loss and apoptosis induced by AlCl3. CONCLUSIONS The results of this study demonstrate that transcranial LIPUS is capable of enhancing the protein levels of neurotrophic factors, which could have neuroprotective effects against neurodegenerative diseases.
Collapse
Affiliation(s)
- Feng-Yi Yang
- Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, Taipei, Taiwan; Biophotonics and Molecular Imaging Research Center, National Yang-Ming University, Taipei, Taiwan.
| | - Wen-Wei Lu
- Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, Taipei, Taiwan
| | - Wei-Ting Lin
- Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, Taipei, Taiwan
| | - Chi-Wei Chang
- National PET/Cyclotron Center, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Sin-Luo Huang
- Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, Taipei, Taiwan
| |
Collapse
|
38
|
Glodzik L, Rusinek H, Li J, Zhou C, Tsui W, Mosconi L, Li Y, Osorio R, Williams S, Randall C, Spector N, McHugh P, Murray J, Pirraglia E, Vallabhajolusa S, de Leon M. Reduced retention of Pittsburgh compound B in white matter lesions. Eur J Nucl Med Mol Imaging 2014; 42:97-102. [PMID: 25331458 DOI: 10.1007/s00259-014-2897-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2014] [Accepted: 08/13/2014] [Indexed: 01/20/2023]
Abstract
PURPOSE One of the interesting features of the amyloid tracer Pittsburgh compound B (PiB) is that it generates a signal in the white matter (WM) in both healthy subjects and cognitively impaired individuals. This characteristic gave rise to the possibility that PiB could be used to trace WM pathology. In a group of cognitively healthy elderly we examined PiB retention in normal-appearing WM (NAWM) and WM lesions (WML), one of the most common brain pathologies in aging. METHODS We segmented WML and NAWM on fluid attenuation inversion recovery (FLAIR) images of 73 subjects (age 61.9 ± 10.0, 71 % women). PiB PET images were corrected for partial volume effects and coregistered to FLAIR images and WM masks. WML and NAWM PiB signals were then extracted. RESULTS PiB retention in WML was lower than in NAWM (p < 0.001, 14.6 % reduction). This was true both for periventricular WML (p < 0.001, 17.8 % reduction) and deep WML (p = 0.001, 7.5 % reduction). CONCLUSION PiB binding in WM is influenced by the presence of WML, which lower the signal. Our findings add to the growing evidence that PiB can depict WM pathology and should prompt further investigations into PiB binding targets in WM.
Collapse
Affiliation(s)
- Lidia Glodzik
- Center for Brain Health, Department of Psychiatry, New York University School of Medicine, 145 East 32nd Street, New York, NY, 10016, USA,
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
39
|
Faria DDP, Copray S, Buchpiguel C, Dierckx R, de Vries E. PET imaging in multiple sclerosis. J Neuroimmune Pharmacol 2014; 9:468-82. [PMID: 24809810 DOI: 10.1007/s11481-014-9544-2] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2014] [Accepted: 04/21/2014] [Indexed: 01/03/2023]
Abstract
Positron emission tomography (PET) is a non-invasive technique for quantitative imaging of biochemical and physiological processes in animals and humans. PET uses probes labeled with a radioactive isotope, called PET tracers, which can bind to or be converted by a specific biological target and thus can be applied to detect and monitor different aspects of diseases. The number of applications of PET imaging in multiple sclerosis is still limited. Clinical studies using PET are basically focused on monitoring changes in glucose metabolism and the presence of activated microglia/macrophages in sclerotic lesions. In preclinical studies, PET imaging of targets for other processes, like demyelination and remyelination, has been investigated and may soon be translated to clinical applications. Moreover, more PET tracers that could be relevant for MS are available now, but have not been studied in this context yet. In this review, we summarize the PET imaging studies performed in multiple sclerosis up to now. In addition, we will identify potential applications of PET imaging of processes or targets that are of interest to MS research, but have yet remained largely unexplored.
Collapse
Affiliation(s)
- Daniele de Paula Faria
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | | | | | | | | |
Collapse
|