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Zou K, Deng Q, Zhang H, Huang C. Glymphatic system: a gateway for neuroinflammation. Neural Regen Res 2024; 19:2661-2672. [PMID: 38595285 PMCID: PMC11168510 DOI: 10.4103/1673-5374.391312] [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: 07/13/2023] [Revised: 09/15/2023] [Accepted: 11/09/2023] [Indexed: 04/11/2024] Open
Abstract
The glymphatic system is a relatively recently identified fluid exchange and transport system in the brain. Accumulating evidence indicates that glymphatic function is impaired not only in central nervous system disorders but also in systemic diseases. Systemic diseases can trigger the inflammatory responses in the central nervous system, occasionally leading to sustained inflammation and functional disturbance of the central nervous system. This review summarizes the current knowledge on the association between glymphatic dysfunction and central nervous system inflammation. In addition, we discuss the hypothesis that disease conditions initially associated with peripheral inflammation overwhelm the performance of the glymphatic system, thereby triggering central nervous system dysfunction, chronic neuroinflammation, and neurodegeneration. Future research investigating the role of the glymphatic system in neuroinflammation may offer innovative therapeutic approaches for central nervous system disorders.
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Affiliation(s)
- Kailu Zou
- Department of Anesthesiology, Xiangya Hospital, Central South University, Changsha, Hunan Province, China
| | - Qingwei Deng
- Department of Anesthesiology, Xiangya Hospital, Central South University, Changsha, Hunan Province, China
| | - Hong Zhang
- Xiangya School of Medicine, Central South University, Changsha, Hunan Province, China
| | - Changsheng Huang
- Department of Anesthesiology, Xiangya Hospital, Central South University, Changsha, Hunan Province, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan Province, China
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Villacis G, Schmidt A, Rudolf JC, Schwenke H, Küchler J, Schramm P, Ulloa P. Evaluating the glymphatic system via magnetic resonance diffusion tensor imaging along the perivascular spaces in brain tumor patients. Jpn J Radiol 2024:10.1007/s11604-024-01602-7. [PMID: 38819694 DOI: 10.1007/s11604-024-01602-7] [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: 12/22/2023] [Accepted: 05/23/2024] [Indexed: 06/01/2024]
Abstract
PURPOSE To investigate glymphatic system function in patients with brain tumors, including both primary and secondary tumors, using diffusion tensor imaging along perivascular spaces (DTI-ALPS). METHODS We retrospectively analyzed the MR DTI of 24 patients with unilateral brain tumors and compared them with age and sex-matched controls. We compared the DTI-ALPS index of the ipsi- and contralateral brain hemispheres. The region of interest was placed in the periventricular vessels adjacent to the lateral ventricles. Differences between sex, age, and kind of tumor (primary or brain metastasis) were evaluated. Correlations between DTI-ALPS index and age and the tumor's apparent diffusion coefficient (ADC) were also investigated. RESULTS The DTI-ALPS index was significantly lower (p < 0.05) in the tumor-affected hemisphere (mean = 1.26 ± 0.24) than contralateral (mean = 1.43 ± 0.28). A comparison with healthy controls revealed no significant difference on the matched ipsilateral side. However, the DTI-ALPS index of the contralateral side of the patients was larger than the HC. Additionally, no statistically significant differences were found when analyzing the DTI-ALPS index vs. age, sex, and tumor entity. Additionally, we did not find a correlation between the DTI-ALPS index and patient age or tumor ADC. CONCLUSION The decreased DTI-ALPS index in the tumor-affected hemisphere may be related to impaired glymphatic system function. However, cancer is often a systemic disease; thus, the DTI-ALPS index from the contralateral brain hemisphere may not generally be considered as a normal control. Nonetheless, the DTI-ALPS index does not only reflect diffusion in the perivascular spaces but it can also be influenced by factors such as axonal degeneration. Therefore, it does not directly reflect brain waste clearance and changes in the index should be interpreted carefully.
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Affiliation(s)
- Gabriela Villacis
- Department of Neuroradiology, University Hospital Schleswig-Holstein (UKSH), Luebeck, Germany
| | - Aileen Schmidt
- Department of Neuroradiology, University Hospital Schleswig-Holstein (UKSH), Luebeck, Germany
| | - Justus C Rudolf
- Department of Neuroradiology, University Hospital Schleswig-Holstein (UKSH), Luebeck, Germany
| | - Hannes Schwenke
- Department of Neuroradiology, University Hospital Schleswig-Holstein (UKSH), Luebeck, Germany
| | - Jan Küchler
- Department of Neurosurgery, University Hospital Schleswig-Holstein (UKSH), Luebeck, Germany
| | - Peter Schramm
- Department of Neuroradiology, University Hospital Schleswig-Holstein (UKSH), Luebeck, Germany
| | - Patricia Ulloa
- Department of Neuroradiology, University Hospital Schleswig-Holstein (UKSH), Luebeck, Germany.
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Schartz D, Finkelstein A, Hoang N, Bender MT, Schifitto G, Zhong J. Diffusion-Weighted Imaging Reveals Impaired Glymphatic Clearance in Idiopathic Intracranial Hypertension. AJNR Am J Neuroradiol 2024; 45:149-154. [PMID: 38238097 DOI: 10.3174/ajnr.a8088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Accepted: 11/02/2023] [Indexed: 02/09/2024]
Abstract
BACKGROUND AND PURPOSE The pathophysiology underlying idiopathic intracranial hypertension (IIH) remains incompletely understood. While one theory postulates impaired cerebral glymphatic clearance in IIH, there is a paucity of methods to quantify glymphatic activity in human brains. The purpose of this study was to use advanced diffusion-weighed imaging to evaluate the glymphatic clearance of IIH patients and how it may relate to clinical severity. MATERIALS AND METHODS DWI was used to separately evaluate the diffusivity along the cerebral perivascular spaces and lateral association and projection fibers, with the degree of diffusivity used as a surrogate for glymphatic function (diffusion tensor image analysis along the perivascular space. Patients with IIH were compared with normal controls. Glymphatic clearance was correlated with several clinical metrics, including lumbar puncture opening pressure and Frisen papilledema grade (low grade: 0-2; high grade: 3-5). RESULTS In total, 99 patients with IIH were identified and compared with 6 healthy controls. Overall, patients with IIH had significantly lower glymphatic clearance based on DWI-derived diffusivity compared with controls (P = .005). Additionally, in patients with IIH, there was a significant association between declining glymphatic clearance and increasing Frisen papilledema grade (P = .046) but no correlation between opening pressure and glymphatic clearance (P = .27). Furthermore, healthy controls had significantly higher glymphatic clearance compared with patients with IIH and low-grade papilledema (P = .015) and high-grade papilledema (P = .002). Lastly, patients with IIH and high-grade papilledema had lower glymphatic clearance compared with patients with IIH and low-grade papilledema (P = .005). CONCLUSIONS Patients with IIH possess impaired glymphatic clearance, which is directly related to the extent of clinical severity. The DWI-derived parameters can be used for clinical diagnosis or to assess response to treatment.
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Affiliation(s)
- Derrek Schartz
- From the Department of Imaging Sciences (D.S., A.F., N.H., G.S., J.Z.), University of Rochester Medical Center, Rochester, New York
| | - Alan Finkelstein
- From the Department of Imaging Sciences (D.S., A.F., N.H., G.S., J.Z.), University of Rochester Medical Center, Rochester, New York
| | - Nhat Hoang
- From the Department of Imaging Sciences (D.S., A.F., N.H., G.S., J.Z.), University of Rochester Medical Center, Rochester, New York
| | - Matthew T Bender
- Department of Neurosurgery (M.T.B.), University of Rochester Medical Center, Rochester, New York
| | - Giovanni Schifitto
- From the Department of Imaging Sciences (D.S., A.F., N.H., G.S., J.Z.), University of Rochester Medical Center, Rochester, New York
- Department of Neurology (G.S.), University of Rochester Medical Center, Rochester, New York
| | - Jianhui Zhong
- From the Department of Imaging Sciences (D.S., A.F., N.H., G.S., J.Z.), University of Rochester Medical Center, Rochester, New York
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Lee DA, Lee HJ, Park KM. Structural connectivity as a predictive factor for responsiveness to levetiracetam treatment in epilepsy. Neuroradiology 2024; 66:93-100. [PMID: 38015213 DOI: 10.1007/s00234-023-03261-3] [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] [Received: 10/25/2023] [Accepted: 11/23/2023] [Indexed: 11/29/2023]
Abstract
PURPOSE To investigate whether structural connectivity or glymphatic system function is a potential predictive factor for levetiracetam (LEV) response in patients with newly diagnosed epilepsy. METHODS We enrolled patients with newly diagnosed epilepsy who were administered LEV as initial monotherapy and underwent diffusion tensor imaging (DTI) at diagnosis. We categorized the patients into drug response. We used graph theory to calculate the network measures for structural connectivity based on the DTI scans in patients with epilepsy. Additionally, we evaluated glymphatic system function by calculating the DTI analysis along the perivascular space (DTI-ALPS) index based on DTI scans. RESULTS We enrolled 84 patients with epilepsy. The clinical factors and DTI-ALPS index did not differ between the groups. However, some of the structural connectivity measures significantly differ between the groups. The poor responders exhibited a higher mean clustering coefficient, global efficiency, and small-worldness index than the good responders (p = 0.003, p = 0.048, and p = 0.038, respectively). In the receiver operating characteristic curve analysis, the mean clustering coefficient exhibited the highest performance in predicting the responsiveness to LEV (area under the curve of 0.677). In the multiple logistic regression analysis, the mean clustering coefficient of the structural connectivity measures was the only significant predictor of LEV response (p = 0.014). Furthermore, in the survival analysis, the mean clustering coefficient was the only significant predictor of LEV response (p = 0.026). CONCLUSION We demonstrated that structural connectivity is a potential predictive factor for responsiveness to LEV treatment in patients with newly diagnosed epilepsy.
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Affiliation(s)
- Dong Ah Lee
- Department of Neurology, Haeundae Paik Hospital, Inje University College of Medicine, Haeundae-ro 875, Haeundae-gu, Busan, 48108, Korea
| | - Ho-Joon Lee
- Department of Radiology, Haeundae Paik Hospital, Inje University College of Medicine, Busan, Republic of Korea
| | - Kang Min Park
- Department of Neurology, Haeundae Paik Hospital, Inje University College of Medicine, Haeundae-ro 875, Haeundae-gu, Busan, 48108, Korea.
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Kim S, Kim SE, Lee DA, Lee H, Park KM. Anti-seizure medication response and the glymphatic system in patients with focal epilepsy. Eur J Neurol 2024; 31:e16097. [PMID: 37823697 PMCID: PMC11235655 DOI: 10.1111/ene.16097] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Revised: 09/14/2023] [Accepted: 09/23/2023] [Indexed: 10/13/2023]
Abstract
BACKGROUND AND PURPOSE We aimed to evaluate (i) glymphatic system function in patients with focal epilepsy in comparison with healthy controls, and (ii) the association between anti-seizure medication (ASM) response and glymphatic system function by using diffusion tensor image analysis along the perivascular space (DTI-ALPS). METHODS We retrospectively enrolled 100 patients with focal epilepsy who had normal brain magnetic resonance imaging (MRI) findings, and classified them as "poor" or "good" ASM responders according to their seizure control at the time of brain MRI. We also included 79 age- and sex-matched healthy controls. All patients and healthy controls underwent conventional brain MRI and diffusion tensor imaging. The DTI-ALPS index was calculated using the DSI studio program. RESULTS Of the 100 patients with focal epilepsy, 38 and 62 were poor and good ASM responders, respectively. The DTI-ALPS index differed significantly between patients with focal epilepsy and healthy controls and was significantly lower in patients with focal epilepsy (1.55 vs. 1.70; p < 0.001). The DTI-ALPS index also differed significantly according to ASM response and was lower in poor ASM responders (1.48 vs. 1.59; p = 0.047). Furthermore, the DTI-ALPS index was negatively correlated with age (r = -0.234, p = 0.019) and duration of epilepsy (r = -0.240, p = 0.016) in patients with focal epilepsy. CONCLUSION Our study is the first to identify, in focal epilepsy patients, a greater reduction in glymphatic system function among poor ASM responders compared to good responders. To confirm our results, further prospective multicenter studies with large sample sizes are needed.
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Affiliation(s)
- Sung‐Tae Kim
- Department of NeurosugeryInje University Busan Paik HospitalBusanKorea
| | - Sung Eun Kim
- Department of Neurology, Haeundae Paik HospitalInje University College of MedicineBusanKorea
| | - Dong Ah Lee
- Department of Neurology, Haeundae Paik HospitalInje University College of MedicineBusanKorea
| | - Ho‐Joon Lee
- Department of Radiology, Haeundae Paik HospitalInje University College of MedicineBusanKorea
| | - Kang Min Park
- Department of Neurology, Haeundae Paik HospitalInje University College of MedicineBusanKorea
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Taoka T, Ito R, Nakamichi R, Nakane T, Kawai H, Naganawa S. Interstitial Fluidopathy of the Central Nervous System: An Umbrella Term for Disorders with Impaired Neurofluid Dynamics. Magn Reson Med Sci 2024; 23:1-13. [PMID: 36436975 PMCID: PMC10838724 DOI: 10.2463/mrms.rev.2022-0012] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Accepted: 08/29/2022] [Indexed: 01/05/2024] Open
Abstract
Interest in interstitial fluid dynamics has increased since the proposal of the glymphatic system hypothesis. Abnormal dynamics of the interstitial fluid have been pointed out to be an important factor in various pathological statuses. In this article, we propose the concept of central nervous system interstitial fluidopathy as a disease or condition in which abnormal interstitial fluid dynamics is one of the important factors for the development of a pathological condition. We discuss the aspects of interstitial fluidopathy in various diseases, including Alzheimer's disease, Parkinson's disease, normal pressure hydrocephalus, and cerebral small vessel disease. We also discuss a method called "diffusion tensor image analysis along the perivascular space" using MR diffusion images, which is used to evaluate the degree of interstitial fluidopathy or the activity of the glymphatic system.
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Affiliation(s)
- Toshiaki Taoka
- Department of Innovative Biomedical Visualization (iBMV), Nagoya University, Nagoya, Aichi, Japan
- Department of Radiology, Nagoya University, Nagoya, Aichi, Japan
| | - Rintaro Ito
- Department of Innovative Biomedical Visualization (iBMV), Nagoya University, Nagoya, Aichi, Japan
- Department of Radiology, Nagoya University, Nagoya, Aichi, Japan
| | - Rei Nakamichi
- Department of Radiology, Nagoya University, Nagoya, Aichi, Japan
| | - Toshiki Nakane
- Department of Radiology, Nagoya University, Nagoya, Aichi, Japan
| | - Hisashi Kawai
- Department of Radiology, Aichi Medical University, Nagakute, Aichi, Japan
| | - Shinji Naganawa
- Department of Radiology, Nagoya University, Nagoya, Aichi, Japan
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Pu W, Wei S, Qiu M, Chen X, Zou W, Ge Y, Qiu W. Dysfunction of the glymphatic system in childhood absence epilepsy. Front Neurosci 2023; 17:1312676. [PMID: 38144207 PMCID: PMC10749194 DOI: 10.3389/fnins.2023.1312676] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Accepted: 11/24/2023] [Indexed: 12/26/2023] Open
Abstract
Objective This study aimed to evaluate the glymphatic system in childhood absence epilepsy (CAE) using diffusion tensor image analysis along the paravascular space (DTI-ALPS) index. Methods: Forty-two CAE patients and 50 age- and gender-matched healthy controls (HC) were included in this study. All participants underwent scanning using a Siemens 3.0 T magnetic resonance scanner, and the DTI-ALPS index was calculated. The study compared the differences of DTI-ALPS index between CAE patients and the healthy controls. Additionally, this study also assessed the relationship between the DTI-ALPS index and clinical characteristics such as age, seizure frequency, and duration of epilepsy. Results The DTI-ALPS index was lower in CAE patients compared to the healthy controls (1.45 ± 0.36 vs. 1.66 ± 0.30, p < 0.01). The DTI-ALPS index showed a negative correlation with the duration of epilepsy (r = -0.48, p < 0.01) and a positive correlation with age (r = 0.766, p < 0.01) in CAE patients. However, no significant correlation was observed between the DTI-ALPS index and seizure frequency. Conclusion The results of this study indicate that children with CAE exhibit dysfunction in the glymphatic system of the brain, which might contribute to understanding the pathophysiological mechanism of CAE. The DTI-ALPS, as a non-invasive diagnostic marker, can be used to assess the function of the glymphatic system in CAE patients, providing promising applications in the diagnosis and research of CAE.
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Affiliation(s)
- Wanqing Pu
- Department of Neurology, The Fifth People’s Hospital of Huai’an, Huai’an, China
| | - Shanzhen Wei
- Department of Electrophysiology, The Affiliated Huai’an Hospital of Xuzhou Medical University, Huai’an, China
| | - Mengdi Qiu
- Department of Neurology, The Fifth People’s Hospital of Huai’an, Huai’an, China
| | - Xiaoyu Chen
- Department of Radiology, The Affiliated Huai’an Hospital of Xuzhou Medical University, Huai’an, China
| | - Wenwei Zou
- Department of Neurology, The Affiliated Huai’an Hospital of Xuzhou Medical University, Huai’an, China
| | - Yingchao Ge
- Department of Neurology, Qidong People’s Hospital, Nantong, China
| | - Wenchao Qiu
- Department of Neurology, The Affiliated Huai’an Hospital of Xuzhou Medical University, Huai’an, China
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Gędek A, Koziorowski D, Szlufik S. Assessment of factors influencing glymphatic activity and implications for clinical medicine. Front Neurol 2023; 14:1232304. [PMID: 37767530 PMCID: PMC10520725 DOI: 10.3389/fneur.2023.1232304] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Accepted: 08/22/2023] [Indexed: 09/29/2023] Open
Abstract
The glymphatic system is a highly specialized fluid transport system in the central nervous system. It enables the exchange of the intercellular fluid of the brain, regulation of the movement of this fluid, clearance of unnecessary metabolic products, and, potentially, brain immunity. In this review, based on the latest scientific reports, we present the mechanism of action and function of the glymphatic system and look at the role of factors influencing its activity. Sleep habits, eating patterns, coexisting stress or hypertension, and physical activity can significantly affect glymphatic activity. Modifying them can help to change lives for the better. In the next section of the review, we discuss the connection between the glymphatic system and neurological disorders. Its association with many disease entities suggests that it plays a major role in the physiology of the whole brain, linking many pathophysiological pathways of individual diseases.
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Affiliation(s)
- Adam Gędek
- Department of Neurology, Faculty of Health Sciences, Medical University of Warsaw, Warsaw, Poland
- Praski Hospital, Warsaw, Poland
| | - Dariusz Koziorowski
- Department of Neurology, Faculty of Health Sciences, Medical University of Warsaw, Warsaw, Poland
| | - Stanisław Szlufik
- Department of Neurology, Faculty of Health Sciences, Medical University of Warsaw, Warsaw, Poland
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Kim J, Lee DA, Lee HJ, Park KM. Glymphatic system dysfunction in patients with occipital lobe epilepsy. J Neuroimaging 2023; 33:455-461. [PMID: 36627235 DOI: 10.1111/jon.13083] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 12/28/2022] [Accepted: 12/30/2022] [Indexed: 01/12/2023] Open
Abstract
BACKGROUND AND PURPOSE We aimed to investigate the glymphatic system function in patients with occipital lobe epilepsy (OLE) and healthy controls using diffusion tensor image analysis along the perivascular space (DTI-ALPS) index. METHODS We retrospectively included 23 patients with OLE and 30 healthy controls. The participants underwent brain MRI, which was normal, and diffusion tensor imaging. We used the DSI Studio for data preprocessing, obtained the fiber orientation and diffusivities, and calculated the DTI-ALPS index from the diffusivity values associated with the projection and association fibers in the left hemisphere. RESULTS There were no differences in mean age (31.6 years [range: 13-58] vs. 31.3 years [range: 20-57], p = .912) and male sex ratio (10/23 [43.5%] vs. 15/30 [50.0%]) between the groups. Compared to healthy controls, the diffusivities in patients with OLE were higher along the Y-axis in the projection fiber and along the Z-axis in the association fiber and lower along the Y-axis in the association fiber. The DTI-ALPS index in patients with OLE was lower than that in the healthy controls (1.421 ± 0.171 vs. 1.667 ± 0.271, p < .001, 95% confidence interval of difference = 0.117-0.376, Test statistic t = 3.823). We found no association between the DTI-ALPS index and clinical characteristics in OLE. CONCLUSION The DTI-ALPS index in patients with OLE was significantly lower than that in healthy controls, suggesting glymphatic system dysfunction in OLE. The DTI-ALPS index could help assess the glymphatic system function in patients with epilepsy.
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Affiliation(s)
- Jinseung Kim
- Department of Family Medicine, Busan Paik Hospital, Inje University College of Medicine, Busan, Republic of Korea
| | - Dong Ah Lee
- Department of Neurology, Haeundae Paik Hospital, Inje University College of Medicine, Busan, Republic of Korea
| | - Ho-Joon Lee
- Department of Radiology, Haeundae Paik Hospital, Inje University College of Medicine, Busan, Republic of Korea
| | - Kang Min Park
- Department of Neurology, Haeundae Paik Hospital, Inje University College of Medicine, Busan, Republic of Korea
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