1
|
Zhang YY, Li JZ, Xie HQ, Jin YX, Wang WT, Zhao B, Jia JM. High-resolution vasomotion analysis reveals novel arteriole physiological features and progressive modulation of cerebral vascular networks by stroke. J Cereb Blood Flow Metab 2024:271678X241258576. [PMID: 38820436 DOI: 10.1177/0271678x241258576] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 06/02/2024]
Abstract
Spontaneous cerebral vasomotion, characterized by ∼0.1 Hz rhythmic contractility, is crucial for brain homeostasis. However, our understanding of vasomotion is limited due to a lack of high-precision analytical methods to determine single vasomotion events at basal levels. Here, we developed a novel strategy that integrates a baseline smoothing algorithm, allowing precise measurements of vasodynamics and concomitant Ca2+ dynamics in mouse cerebral vasculature imaged by two-photon microscopy. We identified several previously unrecognized vasomotion properties under different physiological and pathological conditions, especially in ischemic stroke, which is a highly harmful brain disease that results from vessel occlusion. First, the dynamic characteristics between SMCs Ca2+ and corresponding arteriolar vasomotion are correlated. Second, compared to previous diameter-based estimations, our radius-based measurements reveal anisotropic vascular movements, enabling a more precise determination of the latency between smooth muscle cell (SMC) Ca2+ activity and vasoconstriction. Third, we characterized single vasomotion event kinetics at scales of less than 4 seconds. Finally, following pathological vasoconstrictions induced by ischemic stroke, vasoactive arterioles entered an inert state and persisted despite recanalization. In summary, we developed a highly accurate technique for analyzing spontaneous vasomotion, and our data suggested a potential strategy to reduce stroke damage by promoting vasomotion recovery.
Collapse
Affiliation(s)
- Yi-Yi Zhang
- College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
- Key Laboratory of Growth Regulation and Translation Research of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, China
| | - Jin-Ze Li
- Key Laboratory of Growth Regulation and Translation Research of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, China
| | - Hui-Qi Xie
- Key Laboratory of Growth Regulation and Translation Research of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, China
| | - Yu-Xiao Jin
- Key Laboratory of Growth Regulation and Translation Research of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, China
| | - Wen-Tao Wang
- Key Laboratory of Growth Regulation and Translation Research of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, China
| | - Bingrui Zhao
- Key Laboratory of Growth Regulation and Translation Research of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, China
| | - Jie-Min Jia
- Key Laboratory of Growth Regulation and Translation Research of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, China
- Laboratory of Neurovascular Biology, Institute of Basic Medical Sciences, Westlake Institute for Advanced Study, Hangzhou, China
- Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, China
| |
Collapse
|
2
|
Shahdadian S, Wang X, Liu H. Directed physiological networks in the human prefrontal cortex at rest and post transcranial photobiomodulation. Sci Rep 2024; 14:10242. [PMID: 38702415 PMCID: PMC11068774 DOI: 10.1038/s41598-024-59879-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Accepted: 04/16/2024] [Indexed: 05/06/2024] Open
Abstract
Cerebral infra-slow oscillation (ISO) is a source of vasomotion in endogenic (E; 0.005-0.02 Hz), neurogenic (N; 0.02-0.04 Hz), and myogenic (M; 0.04-0.2 Hz) frequency bands. In this study, we quantified changes in prefrontal concentrations of oxygenated hemoglobin (Δ[HbO]) and redox-state cytochrome c oxidase (Δ[CCO]) as hemodynamic and metabolic activity metrics, and electroencephalogram (EEG) powers as electrophysiological activity, using concurrent measurements of 2-channel broadband near-infrared spectroscopy and EEG on the forehead of 22 healthy participants at rest. After preprocessing, the multi-modality signals were analyzed using generalized partial directed coherence to construct unilateral neurophysiological networks among the three neurophysiological metrics (with simplified symbols of HbO, CCO, and EEG) in each E/N/M frequency band. The links in these networks represent neurovascular, neurometabolic, and metabolicvascular coupling (NVC, NMC, and MVC). The results illustrate that the demand for oxygen by neuronal activity and metabolism (EEG and CCO) drives the hemodynamic supply (HbO) in all E/N/M bands in the resting prefrontal cortex. Furthermore, to investigate the effect of transcranial photobiomodulation (tPBM), we performed a sham-controlled study by delivering an 800-nm laser beam to the left and right prefrontal cortex of the same participants. After performing the same data processing and statistical analysis, we obtained novel and important findings: tPBM delivered on either side of the prefrontal cortex triggered the alteration or reversal of directed network couplings among the three neurophysiological entities (i.e., HbO, CCO, and EEG frequency-specific powers) in the physiological network in the E and N bands, demonstrating that during the post-tPBM period, both metabolism and hemodynamic supply drive electrophysiological activity in directed network coupling of the prefrontal cortex (PFC). Overall, this study revealed that tPBM facilitates significant modulation of the directionality of neurophysiological networks in electrophysiological, metabolic, and hemodynamic activities.
Collapse
Affiliation(s)
- Sadra Shahdadian
- Department of Bioengineering, University of Texas at Arlington, Arlington, TX, 76019, USA
| | - Xinlong Wang
- Department of Bioengineering, University of Texas at Arlington, Arlington, TX, 76019, USA
| | - Hanli Liu
- Department of Bioengineering, University of Texas at Arlington, Arlington, TX, 76019, USA.
| |
Collapse
|
3
|
Hu Z, Li Z, Shi Y, Liu S, Shen Y, Hu F, Li Q, Liu X, Gou X, Chen Z, Yang D. Advancements in investigating the role of cerebral small vein loss in Alzheimer's disease-related pathological changes. Neurol Sci 2024; 45:1875-1883. [PMID: 38133856 DOI: 10.1007/s10072-023-07208-7] [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: 08/16/2023] [Accepted: 11/15/2023] [Indexed: 12/23/2023]
Abstract
Alzheimer's disease (AD) is the prevailing type of dementia in the elderly, yet a comprehensive comprehension of its precise underlying mechanisms remains elusive. The investigation of the involvement of cerebral small veins in the advancement of AD has yet to be sufficiently explored in previous studies, primarily due to constraints associated with pathological staining techniques. However, recent research has provided valuable insights into multiple pathophysiological occurrences concerning cerebral small veins in AD, which may manifest sequentially, concurrently, or in a self-perpetuating manner. These events are presumed to be among the initial processes in the disease's progression. The impact of cerebral small vein loss on amyloid beta (Aβ) clearance through the glial lymphatic system is noteworthy. There exists a potential interdependence between collagen deposition and Aβ deposition in cerebral small veins. The compromised functionality of cerebral small veins can result in decreased cerebral perfusion pressure, potentially leading to cerebral tissue ischemia and edema. Additionally, the reduction of cerebral small veins may facilitate the infiltration of inflammatory factors into the brain parenchyma, thereby eliciting neuroinflammatory responses. Susceptibility-weighted imaging (SWI) is a valuable modality for the efficient assessment of cerebral small veins, precisely the deep medullary vein (DMV), and holds promise for the identification of precise and reliable imaging biomarkers for AD. This review presents a comprehensive overview of the current advancements and obstacles to the impairment of cerebral small veins in AD. Additionally, we emphasize future research avenues and the importance of conducting further investigations in this domain.
Collapse
Affiliation(s)
- Zhenzhu Hu
- Department of Neurology, Hospital of Chengdu University of Traditional Chinese Medicine, Chengdu, 610032, China
| | - Zhaoying Li
- Department of Neurology, Hospital of Chengdu University of Traditional Chinese Medicine, Chengdu, 610032, China
| | - Yu Shi
- Department of Neurology, Xuzhou Cancer Hospital, Xuzhou, 221000, Jiangsu, China
| | - Shanyu Liu
- Department of Neurology, Hospital of Chengdu University of Traditional Chinese Medicine, Chengdu, 610032, China
| | - Yuling Shen
- Department of Neurology, Hospital of Chengdu University of Traditional Chinese Medicine, Chengdu, 610032, China
| | - Fangfang Hu
- Department of Neurology, Xuzhou Cancer Hospital, Xuzhou, 221000, Jiangsu, China
| | - Qingqing Li
- Department of Neurology, Xuzhou Cancer Hospital, Xuzhou, 221000, Jiangsu, China
| | - Xu Liu
- Department of Neurology, Xuzhou Cancer Hospital, Xuzhou, 221000, Jiangsu, China
| | - Xinyu Gou
- Department of Neurology, Guang'an People's Hospital, Guang'an, 638001, China
| | - Zhenwei Chen
- Department of Neurology, Hospital of Chengdu University of Traditional Chinese Medicine, Chengdu, 610032, China
| | - Dongdong Yang
- Department of Neurology, Hospital of Chengdu University of Traditional Chinese Medicine, Chengdu, 610032, China.
| |
Collapse
|
4
|
Loeffler DA. Approaches for Increasing Cerebral Efflux of Amyloid-β in Experimental Systems. J Alzheimers Dis 2024; 100:379-411. [PMID: 38875041 PMCID: PMC11307100 DOI: 10.3233/jad-240212] [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] [Accepted: 05/14/2024] [Indexed: 06/16/2024]
Abstract
Amyloid protein-β (Aβ) concentrations are increased in the brain in both early onset and late onset Alzheimer's disease (AD). In early onset AD, cerebral Aβ production is increased and its clearance is decreased, while increased Aβ burden in late onset AD is due to impaired clearance. Aβ has been the focus of AD therapeutics since development of the amyloid hypothesis, but efforts to slow AD progression by lowering brain Aβ failed until phase 3 trials with the monoclonal antibodies lecanemab and donanemab. In addition to promoting phagocytic clearance of Aβ, antibodies lower cerebral Aβ by efflux of Aβ-antibody complexes across the capillary endothelia, dissolving Aβ aggregates, and a "peripheral sink" mechanism. Although the blood-brain barrier is the main route by which soluble Aβ leaves the brain (facilitated by low-density lipoprotein receptor-related protein-1 and ATP-binding cassette sub-family B member 1), Aβ can also be removed via the blood-cerebrospinal fluid barrier, glymphatic drainage, and intramural periarterial drainage. This review discusses experimental approaches to increase cerebral Aβ efflux via these mechanisms, clinical applications of these approaches, and findings in clinical trials with these approaches in patients with AD or mild cognitive impairment. Based on negative findings in clinical trials with previous approaches targeting monomeric Aβ, increasing the cerebral efflux of soluble Aβ is unlikely to slow AD progression if used as monotherapy. But if used as an adjunct to treatment with lecanemab or donanemab, this approach might allow greater slowing of AD progression than treatment with either antibody alone.
Collapse
Affiliation(s)
- David A. Loeffler
- Department of Neurology, Beaumont Research Institute, Corewell Health, Royal Oak, MI, USA
| |
Collapse
|
5
|
Sissons C, Saeed F, Carter C, Lee K, Kerr K, Shahdadian S, Liu H. Unilateral Mitochondrial-Hemodynamic Coupling and Bilateral Connectivity in the Prefrontal Cortices of Young and Older Healthy Adults. Bioengineering (Basel) 2023; 10:1336. [PMID: 38002460 PMCID: PMC10669330 DOI: 10.3390/bioengineering10111336] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Revised: 11/02/2023] [Accepted: 11/09/2023] [Indexed: 11/26/2023] Open
Abstract
A recent study demonstrated that noninvasive measurements of cortical hemodynamics and metabolism in the resting human prefrontal cortex can facilitate quantitative metrics of unilateral mitochondrial-hemodynamic coupling and bilateral connectivity in infraslow oscillation frequencies in young adults. The infraslow oscillation includes three distinct vasomotions with endogenic (E), neurogenic (N), and myogenic (M) frequency bands. The goal of this study was to prove the hypothesis that there are significant differences between young and older adults in the unilateral coupling (uCOP) and bilateral connectivity (bCON) in the prefrontal cortex. Accordingly, we performed measurements from 24 older adults (67.2 ± 5.9 years of age) using the same two-channel broadband near-infrared spectroscopy (bbNIRS) setup and resting-state experimental protocol as those in the recent study. After quantification of uCOP and bCON in three E/N/M frequencies and statistical analysis, we demonstrated that older adults had significantly weaker bilateral hemodynamic connectivity but significantly stronger bilateral metabolic connectivity than young adults in the M band. Furthermore, older adults exhibited significantly stronger unilateral coupling on both prefrontal sides in all E/N/M bands, particularly with a very large effect size in the M band (>1.9). These age-related results clearly support our hypothesis and were well interpreted following neurophysiological principles. The key finding of this paper is that the neurophysiological metrics of uCOP and bCON are highly associated with age and may have the potential to become meaningful features for human brain health and be translatable for future clinical applications, such as the early detection of Alzheimer's disease.
Collapse
Affiliation(s)
- Claire Sissons
- Department of Bioengineering, University of Texas at Arlington, Arlington, TX 76019, USA
| | - Fiza Saeed
- Department of Bioengineering, University of Texas at Arlington, Arlington, TX 76019, USA
| | - Caroline Carter
- Department of Bioengineering, University of Texas at Arlington, Arlington, TX 76019, USA
| | - Kathy Lee
- School of Social Work, University of Texas at Arlington, Arlington, TX 76019, USA
| | - Kristen Kerr
- School of Social Work, University of Texas at Arlington, Arlington, TX 76019, USA
| | - Sadra Shahdadian
- Department of Bioengineering, University of Texas at Arlington, Arlington, TX 76019, USA
| | - Hanli Liu
- Department of Bioengineering, University of Texas at Arlington, Arlington, TX 76019, USA
| |
Collapse
|
6
|
Bonnar O, Shaw K, Anderle S, Grijseels DM, Clarke D, Bell L, King SL, Hall CN. APOE4 expression confers a mild, persistent reduction in neurovascular function in the visual cortex and hippocampus of awake mice. J Cereb Blood Flow Metab 2023; 43:1826-1841. [PMID: 37350319 PMCID: PMC10676141 DOI: 10.1177/0271678x231172842] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Revised: 03/23/2023] [Accepted: 03/27/2023] [Indexed: 06/24/2023]
Abstract
Vascular factors are known to be early and important players in Alzheimer's disease (AD) development, however the role of the ε4 allele of the Apolipoprotein (APOE) gene (a risk factor for developing AD) remains unclear. APOE4 genotype is associated with early and severe neocortical vascular deficits in anaesthetised mice, but in humans, vascular and cognitive dysfunction are focused on the hippocampal formation and appear later. How APOE4 might interact with the vasculature to confer AD risk during the preclinical phase represents a gap in existing knowledge. To avoid potential confounds of anaesthesia and to explore regions most relevant for human disease, we studied the visual cortex and hippocampus of awake APOE3 and APOE4-TR mice using 2-photon microscopy of neurons and blood vessels. We found mild vascular deficits: vascular density and functional hyperaemia were unaffected in APOE4 mice, and neuronal or vascular function did not decrease up to late middle-age. Instead, vascular responsiveness was lower, arteriole vasomotion was reduced and neuronal calcium signals during visual stimulation were increased. This suggests that, alone, APOE4 expression is not catastrophic but stably alters neurovascular physiology. We suggest this state makes APOE4 carriers more sensitive to subsequent insults such as injury or beta amyloid accumulation.
Collapse
Affiliation(s)
| | | | - Silvia Anderle
- School of Psychology and Sussex Neuroscience, University of Sussex, Falmer, Brighton, East Sussex, UK
| | - Dori M Grijseels
- School of Psychology and Sussex Neuroscience, University of Sussex, Falmer, Brighton, East Sussex, UK
| | - Devin Clarke
- School of Psychology and Sussex Neuroscience, University of Sussex, Falmer, Brighton, East Sussex, UK
| | - Laura Bell
- School of Psychology and Sussex Neuroscience, University of Sussex, Falmer, Brighton, East Sussex, UK
| | - Sarah L King
- School of Psychology and Sussex Neuroscience, University of Sussex, Falmer, Brighton, East Sussex, UK
| | - Catherine N Hall
- School of Psychology and Sussex Neuroscience, University of Sussex, Falmer, Brighton, East Sussex, UK
| |
Collapse
|
7
|
Shahdadian S, Wang X, Liu H. Directed physiological networks in the human prefrontal cortex at rest and post transcranial photobiomodulation. RESEARCH SQUARE 2023:rs.3.rs-3393702. [PMID: 37886539 PMCID: PMC10602070 DOI: 10.21203/rs.3.rs-3393702/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/28/2023]
Abstract
Cerebral infra-slow oscillation (ISO) is a source of vasomotion in endogenic (E; 0.005-0.02 Hz), neurogenic (N; 0.02-0.04 Hz), and myogenic (M; 0.04-0.2 Hz) frequency bands. In this study, we quantified changes in prefrontal concentrations of oxygenated hemoglobin ( Δ [ H b O ] ) and redox-state cytochrome c oxidase ( Δ [ C C O ] ) as hemodynamic and metabolic activity metrics, and electroencephalogram (EEG) powers as electrophysiological activity, using concurrent measurements of 2-channel broadband near-infrared spectroscopy and EEG on the forehead of 22 healthy participants at rest. After preprocessing, the multi-modality signals were analyzed using generalized partial directed coherence to construct unilateral neurophysiological networks among the three neurophysiological metrics (with simplified symbols of HbO, CCO, and EEG) in each E/N/M frequency band. The links in these networks represent neurovascular, neurometabolic, and metabolicvascular coupling (NVC, NMC, and MVC). The results illustrate that the demand for oxygen by neuronal activity and metabolism (EEG and CCO) drives the hemodynamic supply (HbO) in all E/N/M bands in the resting prefrontal cortex. Furthermore, to investigate the effect of transcranial photobiomodulation (tPBM), we performed a sham-controlled study by delivering an 800-nm laser beam to the left and right prefrontal cortex of the same participants. After performing the same data processing and statistical analysis, we obtained novel and important findings: tPBM delivered on either side of the prefrontal cortex triggered the alteration or reversal of directed network couplings among the three neurophysiological entities (i.e., HbO, CCO, and EEG frequency-specific powers) in the physiological network in the E and N bands, demonstrating that during the post-tPBM period, both metabolism and hemodynamic supply drive electrophysiological activity in directed network coupling of the PFC. Overall, this study revealed that tPBM facilitates significant modulation of the directionality of neurophysiological networks in electrophysiological, metabolic, and hemodynamic activities.
Collapse
|
8
|
Prajjwal P, Marsool MDM, Inban P, Sharma B, Asharaf S, Aleti S, Gadam S, Al Sakini AS, Hadi DD. Vascular dementia subtypes, pathophysiology, genetics, neuroimaging, biomarkers, and treatment updates along with its association with Alzheimer's dementia and diabetes mellitus. Dis Mon 2023; 69:101557. [PMID: 37031059 DOI: 10.1016/j.disamonth.2023.101557] [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: 04/10/2023]
Abstract
Dementia is a chronic progressive cognitive decline illness that results in functional impairment. Vascular dementia (VaD), second only to Alzheimer's disease (AD), is one of the most prevalent forms of dementia in the elderly (aged over 65 years), with a varied presentation and unpredictable disease development caused by cerebrovascular or cardiovascular illness. To get a better understanding of the changes occurring in the brain and to drive therapy efforts, new biomarkers for early and precise diagnosis of AD and VaD are required. In this review, Firstly, we describe the subtypes of vascular dementia, their clinical features, pathogenesis, genetics implemented, and their associated neuroimaging and biomarkers, while describing extensively the recent biomarkers discovered in the literature. Secondly, we describe some of the well-documented and other less-defined risk factors and their association and pathophysiology in relation to vascular dementia. Finally, we follow recent updates in the management of vascular dementia along with its association and differentiation from Alzheimer's disease. The aim of this review is to gather the scattered updates and the most recent changes in blood, CSF, and neuroimaging biomarkers related to the multiple subtypes of vascular dementia along with its association with Alzheimer's dementia and diabetes mellitus.
Collapse
Affiliation(s)
| | | | - Pugazhendi Inban
- Internal Medicine, Government Medical College, Omandurar, Chennai, India
| | | | - Shahnaz Asharaf
- Internal Medicine, Travancore Medical College, Kollam, Kerala, India
| | - Soumya Aleti
- PGY-2, Internal Medicine, Berkshire Medical Center, Pittsfield, MA, USA
| | - Srikanth Gadam
- Internal Medicine, Postdoctoral Research Fellow, Mayo Clinic, USA
| | | | - Dalia Dhia Hadi
- University of Baghdad, Al-Kindy College of Medicine, Baghdad, Iraq
| |
Collapse
|
9
|
Matsuzono K, Suzuki M, Anan Y, Ozawa T, Mashiko T, Koide R, Tanaka R, Fujimoto S. Spontaneous Echo Contrast in the Left Atrium and Aortic-Arch Atheroma, Detected by Transesophageal Echocardiography, Was Negatively Correlated with Cognitive Function. J Alzheimers Dis 2023; 91:673-681. [PMID: 36463447 DOI: 10.3233/jad-220763] [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: 12/03/2022]
Abstract
BACKGROUND The relationship between transesophageal echocardiography findings and cognitive function. OBJECTIVE This study aimed to establish an association between transesophageal echocardiography findings and cognitive function in stroke survivors. METHODS A single-center study was conducted between April 1, 2017 and March 31, 2022. All subjects that were included had a past history of ischemic stroke and were admitted after >21 days from onset. The participants underwent cognitive function tests including a Mini-Mental State Examination, Revised Hasegawa Dementia Scale, Frontal Assessment Battery, and transesophageal echocardiography. RESULTS The results of 126 participants were analyzed. The cognitive function of participants with a spontaneous echo contrast (+) in the left atrium including appendage or of those with an aorta-arch plaque with a maximum thickness ≥4 mm significantly worse while neither the patent foramen ovale nor the branch extending plaque influenced cognitive function (The median cognitive scores of the spontaneous echo contrast (-) versus (+) were 26 versus 22, p < 0.01**, 26 versus 21, p < 0.001***, and 14 versus 11, p < 0.01**. Those of the aortic-arch plaque max thickness (<4 mm) versus (≥4 mm) were 26 versus 25, p < 0.05*, 27 versus 24, p < 0.05*, and 15 versus 13, p < 0.05*). CONCLUSION Our findings show that spontaneous echo contrast in the left atrium and aortic-arch atheroma detected by transesophageal echocardiography, were negatively associated with cognitive function.
Collapse
Affiliation(s)
- Kosuke Matsuzono
- Division of Neurology, Department of Medicine, Jichi Medical University, Tochigi, Japan
| | - Masayuki Suzuki
- Division of Neurology, Department of Medicine, Jichi Medical University, Tochigi, Japan
| | - Yuhei Anan
- Division of Neurology, Department of Medicine, Jichi Medical University, Tochigi, Japan
| | - Tadashi Ozawa
- Division of Neurology, Department of Medicine, Jichi Medical University, Tochigi, Japan
| | - Takafumi Mashiko
- Division of Neurology, Department of Medicine, Jichi Medical University, Tochigi, Japan
| | - Reiji Koide
- Division of Neurology, Department of Medicine, Jichi Medical University, Tochigi, Japan
| | - Ryota Tanaka
- Division of Neurology, Department of Medicine, Jichi Medical University, Tochigi, Japan
| | - Shigeru Fujimoto
- Division of Neurology, Department of Medicine, Jichi Medical University, Tochigi, Japan
| |
Collapse
|
10
|
Vargas-Soria M, Ramos-Rodriguez JJ, Del Marco A, Hierro-Bujalance C, Carranza-Naval MJ, Calvo-Rodriguez M, van Veluw SJ, Stitt AW, Simó R, Bacskai BJ, Infante-Garcia C, Garcia-Alloza M. Accelerated amyloid angiopathy and related vascular alterations in a mixed murine model of Alzheimer´s disease and type two diabetes. Fluids Barriers CNS 2022; 19:88. [PMID: 36345028 PMCID: PMC9639294 DOI: 10.1186/s12987-022-00380-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Accepted: 09/26/2022] [Indexed: 11/09/2022] Open
Abstract
BACKGROUND While aging is the main risk factor for Alzheimer´s disease (AD), emerging evidence suggests that metabolic alterations such as type 2 diabetes (T2D) are also major contributors. Indeed, several studies have described a close relationship between AD and T2D with clinical evidence showing that both diseases coexist. A hallmark pathological event in AD is amyloid-β (Aβ) deposition in the brain as either amyloid plaques or around leptomeningeal and cortical arterioles, thus constituting cerebral amyloid angiopathy (CAA). CAA is observed in 85-95% of autopsy cases with AD and it contributes to AD pathology by limiting perivascular drainage of Aβ. METHODS To further explore these alterations when AD and T2D coexist, we have used in vivo multiphoton microscopy to analyze over time the Aβ deposition in the form of plaques and CAA in a relevant model of AD (APPswe/PS1dE9) combined with T2D (db/db). We have simultaneously assessed the effects of high-fat diet-induced prediabetes in AD mice. Since both plaques and CAA are implicated in oxidative-stress mediated vascular damage in the brain, as well as in the activation of matrix metalloproteinases (MMP), we have also analyzed oxidative stress by Amplex Red oxidation, MMP activity by DQ™ Gelatin, and vascular functionality. RESULTS We found that prediabetes accelerates amyloid plaque and CAA deposition, suggesting that initial metabolic alterations may directly affect AD pathology. T2D significantly affects vascular pathology and CAA deposition, which is increased in AD-T2D mice, suggesting that T2D favors vascular accumulation of Aβ. Moreover, T2D synergistically contributes to increase CAA mediated oxidative stress and MMP activation, affecting red blood cell velocity. CONCLUSIONS Our data support the cross-talk between metabolic disease and Aβ deposition that affects vascular integrity, ultimately contributing to AD pathology and related functional changes in the brain microvasculature.
Collapse
Affiliation(s)
- Maria Vargas-Soria
- Division of Physiology. School of Medicine, University of Cadiz, Cadiz, Spain
- Instituto de Investigacion e Innovacion en Ciencias Biomedicas de la Provincia de Cadiz (INIBICA), Cadiz, Spain
| | - Juan Jose Ramos-Rodriguez
- Division of Physiology. School of Medicine, University of Cadiz, Cadiz, Spain
- Currently at Department of Physiology, School of Health Sciences, University of Granada, Granada, Spain
| | - Angel Del Marco
- Division of Physiology. School of Medicine, University of Cadiz, Cadiz, Spain
- Instituto de Investigacion e Innovacion en Ciencias Biomedicas de la Provincia de Cadiz (INIBICA), Cadiz, Spain
| | - Carmen Hierro-Bujalance
- Division of Physiology. School of Medicine, University of Cadiz, Cadiz, Spain
- Instituto de Investigacion e Innovacion en Ciencias Biomedicas de la Provincia de Cadiz (INIBICA), Cadiz, Spain
| | - Maria Jose Carranza-Naval
- Division of Physiology. School of Medicine, University of Cadiz, Cadiz, Spain
- Instituto de Investigacion e Innovacion en Ciencias Biomedicas de la Provincia de Cadiz (INIBICA), Cadiz, Spain
- Salus-Infirmorum, University of Cadiz, Cadiz, Spain
| | - Maria Calvo-Rodriguez
- Alzheimer Research Unit, Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, USA
| | - Susanne J van Veluw
- Alzheimer Research Unit, Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, USA
| | - Alan W Stitt
- Wellcome-Wolfson Institute for Experimental Medicine, Queen's University Belfast, Belfast, Northern Ireland, UK
| | - Rafael Simó
- Diabetes and Metabolism Research Unit, Vall d'Hebron Research Institute, Universitat Autonoma de Barcelona, Barcelona, Spain
- Centro de Investigacion Biomedica en Red de Diabetes y Enfermedades Metabolicas Asociadas (CIBERDEM), Instituto de Salud Carlos III (ISCIII), Madrid, Spain
| | - Brian J Bacskai
- Alzheimer Research Unit, Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, USA
| | - Carmen Infante-Garcia
- Division of Physiology. School of Medicine, University of Cadiz, Cadiz, Spain.
- Instituto de Investigacion e Innovacion en Ciencias Biomedicas de la Provincia de Cadiz (INIBICA), Cadiz, Spain.
| | - Monica Garcia-Alloza
- Division of Physiology. School of Medicine, University of Cadiz, Cadiz, Spain.
- Instituto de Investigacion e Innovacion en Ciencias Biomedicas de la Provincia de Cadiz (INIBICA), Cadiz, Spain.
| |
Collapse
|
11
|
Anderson GK, Rickards CA. The potential therapeutic benefits of low frequency haemodynamic oscillations. J Physiol 2022; 600:3905-3919. [PMID: 35883272 PMCID: PMC9444954 DOI: 10.1113/jp282605] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Accepted: 07/22/2022] [Indexed: 11/08/2022] Open
Abstract
Haemodynamic oscillations occurring at frequencies below the rate of respiration have been observed experimentally for more than a century. Much of the research regarding these oscillations, observed in arterial pressure and blood flow, has focused on mechanisms of generation and methods of quantification. However, examination of the physiological role of these oscillations has been limited. Multiple studies have demonstrated that oscillations in arterial pressure and blood flow are associated with the protection in tissue oxygenation or functional capillary density during conditions of reduced tissue perfusion. There is also evidence that oscillatory blood flow can improve clearance of interstitial fluid, with a growing number of studies demonstrating a role for oscillatory blood flow to aid in clearance of debris from the brain. The therapeutic potential of these haemodynamic oscillations is an important new area of research which may have beneficial impact in treating conditions such as stroke, cardiac arrest, blood loss injuries, sepsis, or even Alzheimer's disease and vascular dementia.
Collapse
Affiliation(s)
- Garen K Anderson
- Cerebral & Cardiovascular Physiology Laboratory, Department of Physiology & Anatomy, University of North Texas Health Science Center, Fort Worth, TX, USA
| | - Caroline A Rickards
- Cerebral & Cardiovascular Physiology Laboratory, Department of Physiology & Anatomy, University of North Texas Health Science Center, Fort Worth, TX, USA
| |
Collapse
|
12
|
An integral perspective of canonical cigarette and e-cigarette-related cardiovascular toxicity based on the adverse outcome pathway framework. J Adv Res 2022:S2090-1232(22)00193-X. [PMID: 35998874 DOI: 10.1016/j.jare.2022.08.012] [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: 06/11/2022] [Revised: 07/29/2022] [Accepted: 08/15/2022] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND Nowadays, cigarette smoking remains the leading cause of chronic disease and premature death, especially cardiovascular disease. As an emerging tobacco product, e-cigarettes have been advocated as alternatives to canonical cigarettes, and thus may be an aid to promote smoking cessation. However, recent studies indicated that e-cigarettes should not be completely harmless to the cardiovascular system. AIM OF REVIEW This review aimed to build up an integral perspective of cigarettes and e-cigarettes-related cardiovascular toxicity. KEY SCIENTIFIC CONCEPTS OF REVIEW This review adopted the adverse outcome pathway (AOP) framework as a pivotal tool and aimed to elucidate the association between the molecular initiating events (MIEs) induced by cigarette and e-cigarette exposure to the cardiovascular adverse outcome. Since the excessive generation of reactive oxygen species (ROS) has been widely approved to play a critical role in cigarette smoke-related CVD and may also be involved in e-cigarette-induced toxic effects, the ROS overproduction and subsequent oxidative stress are regarded as essential parts of this framework. As far as we know, this should be the first AOP framework focusing on cigarette and e-cigarette-related cardiovascular toxicity, and we hope our work to be a guide in exploring the biomarkers and novel therapies for cardiovascular injury.
Collapse
|
13
|
Liu CC, Zhao J, Fu Y, Inoue Y, Ren Y, Chen Y, Doss SV, Shue F, Jeevaratnam S, Bastea L, Wang N, Martens YA, Qiao W, Wang M, Zhao N, Jia L, Yamazaki Y, Yamazaki A, Rosenberg CL, Wang Z, Kong D, Li Z, Kuchenbecker LA, Trottier ZA, Felton L, Rogers J, Quicksall ZS, Linares C, Knight J, Chen Y, Kurti A, Kanekiyo T, Fryer JD, Asmann YW, Storz P, Wang X, Peng J, Zhang B, Kim BYS, Bu G. Peripheral apoE4 enhances Alzheimer's pathology and impairs cognition by compromising cerebrovascular function. Nat Neurosci 2022; 25:1020-1033. [PMID: 35915180 PMCID: PMC10009873 DOI: 10.1038/s41593-022-01127-0] [Citation(s) in RCA: 67] [Impact Index Per Article: 33.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Accepted: 06/22/2022] [Indexed: 12/21/2022]
Abstract
The ε4 allele of the apolipoprotein E (APOE) gene, a genetic risk factor for Alzheimer's disease, is abundantly expressed in both the brain and periphery. Here, we present evidence that peripheral apoE isoforms, separated from those in the brain by the blood-brain barrier, differentially impact Alzheimer's disease pathogenesis and cognition. To evaluate the function of peripheral apoE, we developed conditional mouse models expressing human APOE3 or APOE4 in the liver with no detectable apoE in the brain. Liver-expressed apoE4 compromised synaptic plasticity and cognition by impairing cerebrovascular functions. Plasma proteome profiling revealed apoE isoform-dependent functional pathways highlighting cell adhesion, lipoprotein metabolism and complement activation. ApoE3 plasma from young mice improved cognition and reduced vessel-associated gliosis when transfused into aged mice, whereas apoE4 compromised the beneficial effects of young plasma. A human induced pluripotent stem cell-derived endothelial cell model recapitulated the plasma apoE isoform-specific effect on endothelial integrity, further supporting a vascular-related mechanism. Upon breeding with amyloid model mice, liver-expressed apoE4 exacerbated brain amyloid pathology, whereas apoE3 reduced it. Our findings demonstrate pathogenic effects of peripheral apoE4, providing a strong rationale for targeting peripheral apoE to treat Alzheimer's disease.
Collapse
Affiliation(s)
- Chia-Chen Liu
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, USA.
| | - Jing Zhao
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, USA
| | - Yuan Fu
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, USA
| | - Yasuteru Inoue
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, USA
| | - Yingxue Ren
- Department of Quantitative Health Sciences, Mayo Clinic, Jacksonville, FL, USA
| | - Yuanxin Chen
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, USA
| | - Sydney V Doss
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, USA
| | - Francis Shue
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, USA
| | | | - Ligia Bastea
- Department of Cancer Biology, Mayo Clinic, Jacksonville, FL, USA
| | - Na Wang
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, USA
| | - Yuka A Martens
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, USA
| | - Wenhui Qiao
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, USA
| | - Minghui Wang
- Department of Cancer Biology, Mayo Clinic, Jacksonville, FL, USA
| | - Na Zhao
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, USA
| | - Lin Jia
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, USA
| | - Yu Yamazaki
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, USA
| | - Akari Yamazaki
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, USA
| | | | - Zhen Wang
- Departments of Structural Biology and Developmental Neurobiology, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Dehui Kong
- Department of Biology, University of North Dakota, Grand Forks, ND, USA
| | - Zonghua Li
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, USA
| | | | | | - Lindsey Felton
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, USA
| | - Justin Rogers
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, USA
| | | | - Cynthia Linares
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, USA
| | - Joshua Knight
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, USA
| | - Yixing Chen
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, USA
| | - Aishe Kurti
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, USA
| | | | - John D Fryer
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, USA
| | - Yan W Asmann
- Department of Quantitative Health Sciences, Mayo Clinic, Jacksonville, FL, USA
| | - Peter Storz
- Department of Cancer Biology, Mayo Clinic, Jacksonville, FL, USA
| | - Xusheng Wang
- Department of Biology, University of North Dakota, Grand Forks, ND, USA
| | - Junmin Peng
- Departments of Structural Biology and Developmental Neurobiology, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Bin Zhang
- Department of Genetics and Genomic Sciences, Mount Sinai Center for Transformative Disease Modeling, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Betty Y S Kim
- Department of Neurosurgery, The Brain Tumor Center, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Guojun Bu
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, USA.
| |
Collapse
|
14
|
Altered retinal cerebral vessel oscillation frequencies in Alzheimer's disease compatible with impaired amyloid clearance. Neurobiol Aging 2022; 120:117-127. [DOI: 10.1016/j.neurobiolaging.2022.08.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Revised: 08/20/2022] [Accepted: 08/23/2022] [Indexed: 11/15/2022]
|
15
|
Shahdadian S, Wang X, Kang S, Carter C, Chaudhari A, Liu H. Prefrontal cortical connectivity and coupling of infraslow oscillation in the resting human brain: a 2-channel broadband NIRS study. Cereb Cortex Commun 2022; 3:tgac033. [PMID: 36072711 PMCID: PMC9441674 DOI: 10.1093/texcom/tgac033] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2022] [Revised: 07/19/2022] [Accepted: 07/23/2022] [Indexed: 11/12/2022] Open
Abstract
Abstract
The resting-state infraslow oscillation (ISO) of the cerebral cortex reflects the neurophysiological state of the human brain. ISO results from distinct vasomotion with endogenic (E), neurogenic (N), and myogenic (M) frequency bands. Quantification of prefrontal ISO in cortical hemodynamics and metabolism in the resting human brain may facilitate the identification of objective features that are characteristic of certain brain disorders. The goal of this study was to explore and quantify the prefrontal ISO of the cortical concentration changes of oxygenated hemoglobin (Δ[HbO]) and redox-state cytochrome c oxidase (Δ[CCO]) as hemodynamic and metabolic activity metrics in all 3 E/N/M bands. Two-channel broadband near-infrared spectroscopy (2-bbNIRS) enabled measurements of the forehead of 26 healthy young participants in a resting state once a week for 5 weeks. After quantifying the ISO spectral amplitude (SA) and coherence at each E/N/M band, several key and statistically reliable metrics were obtained as features: (i) SA of Δ[HbO] at all E/N/M bands, (ii) SA of Δ[CCO] in the M band, (iii) bilateral connectivity of hemodynamics and metabolism across the E and N bands, and (iv) unilateral hemodynamic–metabolic coupling in each of the E and M bands. These features have promising potential to be developed as objective biomarkers for clinical applications in the future.
Collapse
Affiliation(s)
- Sadra Shahdadian
- Department of Bioengineering, The University of Texas at Arlington , 500 UTA Blvd, Arlington, TX 76019, United States
| | - Xinlong Wang
- Department of Bioengineering, The University of Texas at Arlington , 500 UTA Blvd, Arlington, TX 76019, United States
| | - Shu Kang
- Department of Bioengineering, The University of Texas at Arlington , 500 UTA Blvd, Arlington, TX 76019, United States
| | - Caroline Carter
- Department of Bioengineering, The University of Texas at Arlington , 500 UTA Blvd, Arlington, TX 76019, United States
| | - Akhil Chaudhari
- Department of Bioengineering, The University of Texas at Arlington , 500 UTA Blvd, Arlington, TX 76019, United States
| | - Hanli Liu
- Department of Bioengineering, The University of Texas at Arlington , 500 UTA Blvd, Arlington, TX 76019, United States
| |
Collapse
|
16
|
Blood-brain barrier leakage in Alzheimer's disease: From discovery to clinical relevance. Pharmacol Ther 2022; 234:108119. [PMID: 35108575 PMCID: PMC9107516 DOI: 10.1016/j.pharmthera.2022.108119] [Citation(s) in RCA: 44] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 01/14/2022] [Accepted: 01/18/2022] [Indexed: 12/16/2022]
Abstract
Alzheimer's disease (AD) is the most common form of dementia. AD brain pathology starts decades before the onset of clinical symptoms. One early pathological hallmark is blood-brain barrier dysfunction characterized by barrier leakage and associated with cognitive decline. In this review, we summarize the existing literature on the extent and clinical relevance of barrier leakage in AD. First, we focus on AD animal models and their susceptibility to barrier leakage based on age and genetic background. Second, we re-examine barrier dysfunction in clinical and postmortem studies, summarize changes that lead to barrier leakage in patients and highlight the clinical relevance of barrier leakage in AD. Third, we summarize signaling mechanisms that link barrier leakage to neurodegeneration and cognitive decline in AD. Finally, we discuss clinical relevance and potential therapeutic strategies and provide future perspectives on investigating barrier leakage in AD. Identifying mechanistic steps underlying barrier leakage has the potential to unravel new targets that can be used to develop novel therapeutic strategies to repair barrier leakage and slow cognitive decline in AD and AD-related dementias.
Collapse
|
17
|
Chen F, Xie X, Wang L. Research Progress on Intracranial Lymphatic Circulation and Its Involvement in Disorders. Front Neurol 2022; 13:865714. [PMID: 35359624 PMCID: PMC8963982 DOI: 10.3389/fneur.2022.865714] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2022] [Accepted: 02/14/2022] [Indexed: 12/14/2022] Open
Abstract
The lymphatic system is an important part of the circulatory system, as an auxiliary system of the vein, which has the functions of immune defense, maintaining the stability of the internal environment, and regulating the pressure of the tissue. It has long been thought that there are no typical lymphatic vessels consisting of endothelial cells in the central nervous system (CNS). In recent years, studies have confirmed the presence of lymphatic vessels lined with endothelial cells in the meninges. The periventricular meninges of the CNS host different populations of immune cells that affect the immune response associated with the CNS, and the continuous drainage of interstitial and cerebrospinal fluid produced in the CNS also proceeds mainly by the lymphatic system. This fluid process mobilizes to a large extent the transfer of antigens produced by the CNS to the meningeal immune cells and subsequently to the peripheral immune system through the lymphatic network, with clinically important implications for infectious diseases, autoimmunity, and tumor immunology. In our review, we discussed recent research advances in intracranial lymphatic circulation and the pathogenesis of its associated diseases, especially the discovery of meningeal lymphatic vessels, which has led to new therapeutic targets for the treatment of diseases associated with the intracranial lymphatic system.
Collapse
Affiliation(s)
- Fan Chen
- Department of Neurosurgery, Tangdu Hospital of Fourth Military Medical University, Xi'an, China
| | - Xuan Xie
- Department of Neurosurgery, Tangdu Hospital of Fourth Military Medical University, Xi'an, China
| | - Liang Wang
- Department of Neurosurgery, Tangdu Hospital of Fourth Military Medical University, Xi'an, China
| |
Collapse
|
18
|
Gallego I, Villate-Beitia I, Saenz-Del-Burgo L, Puras G, Pedraz JL. Therapeutic Opportunities and Delivery Strategies for Brain Revascularization in Stroke, Neurodegeneration, and Aging. Pharmacol Rev 2022; 74:439-461. [PMID: 35302047 DOI: 10.1124/pharmrev.121.000418] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 01/18/2022] [Accepted: 01/22/2022] [Indexed: 12/25/2022] Open
Abstract
Central nervous system (CNS) diseases, especially acute ischemic events and neurodegenerative disorders, constitute a public health problem with no effective treatments to allow a persistent solution. Failed therapies targeting neuronal recovery have revealed the multifactorial and intricate pathophysiology underlying such CNS disorders as ischemic stroke, Alzheimeŕs disease, amyotrophic lateral sclerosis, vascular Parkisonism, vascular dementia, and aging, in which cerebral microvasculature impairment seems to play a key role. In fact, a reduction in vessel density and cerebral blood flow occurs in these scenarios, contributing to neuronal dysfunction and leading to loss of cognitive function. In this review, we provide an overview of healthy brain microvasculature structure and function in health and the effect of the aforementioned cerebral CNS diseases. We discuss the emerging new therapeutic opportunities, and their delivery approaches, aimed at recovering brain vascularization in this context. SIGNIFICANCE STATEMENT: The lack of effective treatments, mainly focused on neuron recovery, has prompted the search of other therapies to treat cerebral central nervous system diseases. The disruption and degeneration of cerebral microvasculature has been evidenced in neurodegenerative diseases, stroke, and aging, constituting a potential target for restoring vascularization, neuronal functioning, and cognitive capacities by the development of therapeutic pro-angiogenic strategies.
Collapse
Affiliation(s)
- Idoia Gallego
- NanoBioCel Research Group, Laboratory of Pharmacy and Pharmaceutical Technology, Faculty of Pharmacy, University of the Basque Country UPV/EHU, Vitoria-Gasteiz, Spain (I.G., I.V.-B., L.S.-B., G.P., J.L.P); Networking Research Centre of Bioengineering, Biomaterials and Nanomedicine, Institute of Health Carlos III, Madrid, Spain (I.G., I.V.-B., L.S.-B., G.P., J.L.P.); and Bioaraba, NanoBioCel Research Group, Vitoria-Gasteiz, Spain (I.G., I.V.-B., L.S.-B., G.P., J.L.P.)
| | - Ilia Villate-Beitia
- NanoBioCel Research Group, Laboratory of Pharmacy and Pharmaceutical Technology, Faculty of Pharmacy, University of the Basque Country UPV/EHU, Vitoria-Gasteiz, Spain (I.G., I.V.-B., L.S.-B., G.P., J.L.P); Networking Research Centre of Bioengineering, Biomaterials and Nanomedicine, Institute of Health Carlos III, Madrid, Spain (I.G., I.V.-B., L.S.-B., G.P., J.L.P.); and Bioaraba, NanoBioCel Research Group, Vitoria-Gasteiz, Spain (I.G., I.V.-B., L.S.-B., G.P., J.L.P.)
| | - Laura Saenz-Del-Burgo
- NanoBioCel Research Group, Laboratory of Pharmacy and Pharmaceutical Technology, Faculty of Pharmacy, University of the Basque Country UPV/EHU, Vitoria-Gasteiz, Spain (I.G., I.V.-B., L.S.-B., G.P., J.L.P); Networking Research Centre of Bioengineering, Biomaterials and Nanomedicine, Institute of Health Carlos III, Madrid, Spain (I.G., I.V.-B., L.S.-B., G.P., J.L.P.); and Bioaraba, NanoBioCel Research Group, Vitoria-Gasteiz, Spain (I.G., I.V.-B., L.S.-B., G.P., J.L.P.)
| | - Gustavo Puras
- NanoBioCel Research Group, Laboratory of Pharmacy and Pharmaceutical Technology, Faculty of Pharmacy, University of the Basque Country UPV/EHU, Vitoria-Gasteiz, Spain (I.G., I.V.-B., L.S.-B., G.P., J.L.P); Networking Research Centre of Bioengineering, Biomaterials and Nanomedicine, Institute of Health Carlos III, Madrid, Spain (I.G., I.V.-B., L.S.-B., G.P., J.L.P.); and Bioaraba, NanoBioCel Research Group, Vitoria-Gasteiz, Spain (I.G., I.V.-B., L.S.-B., G.P., J.L.P.)
| | - José Luis Pedraz
- NanoBioCel Research Group, Laboratory of Pharmacy and Pharmaceutical Technology, Faculty of Pharmacy, University of the Basque Country UPV/EHU, Vitoria-Gasteiz, Spain (I.G., I.V.-B., L.S.-B., G.P., J.L.P); Networking Research Centre of Bioengineering, Biomaterials and Nanomedicine, Institute of Health Carlos III, Madrid, Spain (I.G., I.V.-B., L.S.-B., G.P., J.L.P.); and Bioaraba, NanoBioCel Research Group, Vitoria-Gasteiz, Spain (I.G., I.V.-B., L.S.-B., G.P., J.L.P.)
| |
Collapse
|
19
|
Wardlaw JM, Benveniste H, Williams A. Cerebral Vascular Dysfunctions Detected in Human Small Vessel Disease and Implications for Preclinical Studies. Annu Rev Physiol 2022; 84:409-434. [PMID: 34699267 DOI: 10.1146/annurev-physiol-060821-014521] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Cerebral small vessel disease (SVD) is highly prevalent and a common cause of ischemic and hemorrhagic stroke and dementia, yet the pathophysiology is poorly understood. Its clinical expression is highly varied, and prognostic implications are frequently overlooked in clinics; thus, treatment is currently confined to vascular risk factor management. Traditionally, SVD is considered the small vessel equivalent of large artery stroke (occlusion, rupture), but data emerging from human neuroimaging and genetic studies refute this, instead showing microvessel endothelial dysfunction impacting on cell-cell interactions and leading to brain damage. These dysfunctions reflect defects that appear to be inherited and secondary to environmental exposures, including vascular risk factors. Interrogation in preclinical models shows consistent and converging molecular and cellular interactions across the endothelial-glial-neural unit that increasingly explain the human macroscopic observations and identify common patterns of pathology despite different triggers. Importantly, these insights may offer new targets for therapeutic intervention focused on restoring endothelial-glial physiology.
Collapse
Affiliation(s)
- Joanna M Wardlaw
- Division of Neuroimaging Sciences, Centre for Clinical Brain Sciences; UK Dementia Research Institute; and Edinburgh Imaging, University of Edinburgh, Edinburgh, United Kingdom;
| | - Helene Benveniste
- Department of Anesthesiology, Yale School of Medicine, New Haven, Connecticut, USA
| | - Anna Williams
- Centre for Regenerative Medicine, Institute for Regeneration and Repair, University of Edinburgh, Edinburgh, United Kingdom
| |
Collapse
|
20
|
Wang X, Ma LC, Shahdadian S, Wu A, Truong NCD, Liu H. Metabolic Connectivity and Hemodynamic-Metabolic Coherence of Human Prefrontal Cortex at Rest and Post Photobiomodulation Assessed by Dual-Channel Broadband NIRS. Metabolites 2022; 12:42. [PMID: 35050164 PMCID: PMC8778041 DOI: 10.3390/metabo12010042] [Citation(s) in RCA: 4] [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: 11/30/2021] [Revised: 12/27/2021] [Accepted: 01/04/2022] [Indexed: 02/05/2023] Open
Abstract
Billions of neurons in the human brain form neural networks with oscillation rhythms. Infra-slow oscillation (ISO) presents three main physiological sources: endogenic, neurogenic, and myogenic vasomotions. Having an in vivo methodology for the absolute quantification of ISO from the human brain can facilitate the detection of brain abnormalities in cerebral hemodynamic and metabolic activities. In this study, we introduced a novel measurement-plus-analysis framework for the non-invasive quantification of prefrontal ISO by (1) taking dual-channel broadband near infrared spectroscopy (bbNIRS) measurements from 12 healthy humans during a 6-min rest and 4-min post transcranial photobiomodulation (tPBM) and (2) performing wavelet transform coherence (WTC) analysis on the measured time series data. The WTC indexes (IC, between 0 and 1) enabled the assessment of ipsilateral hemodynamic-metabolic coherence and bilateral functional connectivity in each ISO band of the human prefrontal cortex. At rest, bilateral hemodynamic connectivity was consistent across the three ISO bands (IC ≅ 0.66), while bilateral metabolic connectivity was relatively weaker. For post-tPBM/sham comparison, our analyses revealed three key findings: 8-min, right-forehead, 1064-nm tPBM (1) enhanced the amplitude of metabolic oscillation bilaterally, (2) promoted the bilateral metabolic connectivity of neurogenic rhythm, and (3) made the main effect on endothelial cells, causing alteration of hemodynamic-metabolic coherence on each side of the prefrontal cortex.
Collapse
Affiliation(s)
| | | | | | | | | | - Hanli Liu
- Department of Bioengineering, University of Texas at Arlington, 500 UTA Blvd, Arlington, TX 76019, USA; (X.W.); (L.-C.M.); (S.S.); (A.W.); (N.C.D.T.)
| |
Collapse
|
21
|
Matsuzono K, Suzuki M, Miura K, Ozawa T, Mashiko T, Koide R, Tanaka R, Fujimoto S. Internal Jugular Vein Velocity and Spontaneous Echo Contrast Correlate with Alzheimer's Disease and Cognitive Function. J Alzheimers Dis 2021; 84:787-796. [PMID: 34602471 DOI: 10.3233/jad-210490] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
BACKGROUND Many issues persist in the today's Alzheimer's disease (AD) screening and the breakthrough method is desired. OBJECTIVE We aim to validate the association between venous reflux and AD, and to develop a new method for AD screening. METHODS We examined spontaneous echo contrast, area, diameter, retrograde velocity, and anterograde velocity of the bilateral cervical internal jugular vein (IJV) using carotid ultrasonography. RESULTS A total of 112 patients participated in this study, with 26 diagnosed as AD. The proportion of both or either IJV spontaneous echo contrast (+) occupied 25 of total 26 AD patients, which showed 96.2%of sensitivity and 98.5%negative predictive value. The IJV velocities also showed significant correlation with AD diagnosis, although the IJV area or diameter did not. CONCLUSION Our results indicate that the validation of the spontaneous echo contrast or velocities of the IJV are convenient AD diagnosis screening methods and that the venous reflux disturbance correlates with AD development.
Collapse
Affiliation(s)
- Kosuke Matsuzono
- Division of Neurology, Department of Medicine, Jichi Medical University, Tochigi, Japan
| | - Masayuki Suzuki
- Division of Neurology, Department of Medicine, Jichi Medical University, Tochigi, Japan
| | - Kumiko Miura
- Division of Neurology, Department of Medicine, Jichi Medical University, Tochigi, Japan
| | - Tadashi Ozawa
- Division of Neurology, Department of Medicine, Jichi Medical University, Tochigi, Japan
| | - Takafumi Mashiko
- Division of Neurology, Department of Medicine, Jichi Medical University, Tochigi, Japan
| | - Reiji Koide
- Division of Neurology, Department of Medicine, Jichi Medical University, Tochigi, Japan
| | - Ryota Tanaka
- Division of Neurology, Department of Medicine, Jichi Medical University, Tochigi, Japan
| | - Shigeru Fujimoto
- Division of Neurology, Department of Medicine, Jichi Medical University, Tochigi, Japan
| |
Collapse
|
22
|
Kolinko Y, Marsalova L, Proskauer Pena S, Kralickova M, Mouton PR. Stereological Changes in Microvascular Parameters in Hippocampus of a Transgenic Rat Model of Alzheimer's Disease. J Alzheimers Dis 2021; 84:249-260. [PMID: 34542078 PMCID: PMC8609684 DOI: 10.3233/jad-210738] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Background: Microcirculatory factors play an important role in amyloid-β (Aβ)-related neuropathology in Alzheimer’s disease (AD). Transgenic (Tg) rat models of mutant Aβ deposition can enhance our understanding of this microvascular pathology. Objective: Here we report stereology-based quantification and comparisons (between- and within-group) of microvessel length and number and associated parameters in hippocampal subregions in Tg model of AD in Fischer 344 rats and non-Tg littermates. Methods: Systematic-random samples of tissue sections were processed and laminin immunostained to visualize microvessels through the entire hippocampus in Tg and non-Tg rats. A computer-assisted stereology system was used to quantify microvessel parameters including total number, total length, and associated densities in dentate gyrus (DG) and cornu ammonis (CA) subregions. Results: Thin hair-like capillaries are common near Aβ plaques in hippocampal subregions of Tg rats. There are a 53% significant increase in average length per capillary across entire hippocampus (p≤0.04) in Tg compared to non-Tg rats; 49% reduction in capillary length in DG (p≤0.02); and, higher microvessel density in principal cell layers (p≤0.03). Furthermore, within-group comparisons confirm Tg but not non-Tg rats have significant increase in number density (p≤0.01) and potential diffusion distance (p≤0.04) of microvessels in principal cell layers of hippocampal subregions. Conclusion: We show the Tg deposition of human Aβ mutations in rats disrupts the wild-type microanatomy of hippocampal microvessels. Stereology-based microvascular parameters could promote the development of novel strategies for protection and the therapeutic management of AD.
Collapse
Affiliation(s)
- Yaroslav Kolinko
- Biomedical Center, Faculty of Medicine in Pilsen, Charles University, Pilsen, Czech Republic.,Department of Histology and Embryology, Faculty of Medicine in Pilsen, Charles University, Pilsen, Czech Republic
| | - Lucie Marsalova
- Biomedical Center, Faculty of Medicine in Pilsen, Charles University, Pilsen, Czech Republic.,Department of Histology and Embryology, Faculty of Medicine in Pilsen, Charles University, Pilsen, Czech Republic
| | | | - Milena Kralickova
- Biomedical Center, Faculty of Medicine in Pilsen, Charles University, Pilsen, Czech Republic.,Department of Histology and Embryology, Faculty of Medicine in Pilsen, Charles University, Pilsen, Czech Republic
| | - Peter R Mouton
- SRC Biosciences, Tampa, FL, USA.,University of South Florida, Tampa, FL, USA
| |
Collapse
|
23
|
Haidey JN, Peringod G, Institoris A, Gorzo KA, Nicola W, Vandal M, Ito K, Liu S, Fielding C, Visser F, Nguyen MD, Gordon GR. Astrocytes regulate ultra-slow arteriole oscillations via stretch-mediated TRPV4-COX-1 feedback. Cell Rep 2021; 36:109405. [PMID: 34348138 DOI: 10.1016/j.celrep.2021.109405] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 02/22/2021] [Accepted: 06/24/2021] [Indexed: 12/20/2022] Open
Abstract
Very-low-frequency oscillations in microvascular diameter cause fluctuations in oxygen delivery that are important for fueling the brain and for functional imaging. However, little is known about how the brain regulates ongoing oscillations in cerebral blood flow. In mouse and rat cortical brain slice arterioles, we find that selectively enhancing tone is sufficient to recruit a TRPV4-mediated Ca2+ elevation in adjacent astrocyte endfeet. This endfoot Ca2+ signal triggers COX-1-mediated "feedback vasodilators" that limit the extent of evoked vasoconstriction, as well as constrain fictive vasomotion in slices. Astrocyte-Ptgs1 knockdown in vivo increases the power of arteriole oscillations across a broad range of very low frequencies (0.01-0.3 Hz), including ultra-slow vasomotion (∼0.1 Hz). Conversely, clamping astrocyte Ca2+in vivo reduces the power of vasomotion. These data demonstrate bidirectional communication between arterioles and astrocyte endfeet to regulate oscillatory microvasculature activity.
Collapse
Affiliation(s)
- Jordan N Haidey
- Hotchkiss Brain Institute, Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Govind Peringod
- Hotchkiss Brain Institute, Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Adam Institoris
- Hotchkiss Brain Institute, Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Kelsea A Gorzo
- Hotchkiss Brain Institute, Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Wilten Nicola
- Hotchkiss Brain Institute, Department of Cell Biology and Anatomy, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada; Department of Physics and Astronomy, Faculty of Science, University of Calgary, Calgary, AB T2N 1N4, Canada
| | - Milène Vandal
- Hotchkiss Brain Institute, Department of Clinical Neurosciences, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Kenichi Ito
- Centre for Genome Engineering, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Shiying Liu
- Centre for Genome Engineering, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Cameron Fielding
- Centre for Genome Engineering, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Frank Visser
- Hotchkiss Brain Institute, Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Minh Dang Nguyen
- Hotchkiss Brain Institute, Department of Clinical Neurosciences, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Grant R Gordon
- Hotchkiss Brain Institute, Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada.
| |
Collapse
|
24
|
Babusikova E, Dobrota D, Turner AJ, Nalivaeva NN. Effect of Global Brain Ischemia on Amyloid Precursor Protein Metabolism and Expression of Amyloid-Degrading Enzymes in Rat Cortex: Role in Pathogenesis of Alzheimer's Disease. BIOCHEMISTRY (MOSCOW) 2021; 86:680-692. [PMID: 34225591 DOI: 10.1134/s0006297921060067] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The incidence of Alzheimer's disease (AD) increases significantly following chronic stress and brain ischemia which, over the years, cause accumulation of toxic amyloid species and brain damage. The effects of global 15-min ischemia and 120-min reperfusion on the levels of expression of the amyloid precursor protein (APP) and its processing were investigated in the brain cortex (Cx) of male Wistar rats. Additionally, the levels of expression of the amyloid-degrading enzymes neprilysin (NEP), endothelin-converting enzyme-1 (ECE-1), and insulin-degrading enzyme (IDE), as well as of some markers of oxidative damage were assessed. It was shown that the APP mRNA and protein levels in the rat Cx were significantly increased after the ischemic insult. Protein levels of the soluble APP fragments, especially of sAPPβ produced by β-secretase, (BACE-1) and the levels of BACE-1 mRNA and protein expression itself were also increased after ischemia. The protein levels of APP and BACE-1 in the Cx returned to the control values after 120-min reperfusion. The levels of NEP and ECE-1 mRNA also decreased after ischemia, which correlated with the decreased protein levels of these enzymes. However, we have not observed any changes in the protein levels of insulin-degrading enzyme. Contents of the markers of oxidative damage (di-tyrosine and lysine conjugates with lipid peroxidation products) were also increased after ischemia. The obtained data suggest that ischemia shifts APP processing towards the amyloidogenic β-secretase pathway and accumulation of the neurotoxic Aβ peptide as well as triggers oxidative stress in the cells. These results are discussed in the context of the role of stress and ischemia in initiation and progression of AD.
Collapse
Affiliation(s)
- Eva Babusikova
- Comenius University in Bratislava, Jessenius Faculty of Medicine in Martin, Department of Medical Biochemistry, Martin, 036 01, Slovakia.
| | - Dusan Dobrota
- Comenius University in Bratislava, Jessenius Faculty of Medicine in Martin, Department of Medical Biochemistry, Martin, 036 01, Slovakia.
| | - Anthony J Turner
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, United Kingdom.
| | - Natalia N Nalivaeva
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, United Kingdom. .,Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, St. Petersburg, 194223, Russia
| |
Collapse
|
25
|
Liu D, Ahmet I, Griess B, Tweedie D, Greig NH, Mattson MP. Age-related impairment of cerebral blood flow response to K ATP channel opener in Alzheimer's disease mice with presenilin-1 mutation. J Cereb Blood Flow Metab 2021; 41:1579-1591. [PMID: 33203296 PMCID: PMC8221766 DOI: 10.1177/0271678x20964233] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Local cerebral blood flow (CBF) responses to neuronal activity are essential for cognition and impaired CBF responses occur in Alzheimer's disease (AD). In this study, regional CBF (rCBF) responses to the KATP channel opener diazoxide were investigated in 3xTgAD, WT and mutant Presenilin 1(PS1M146V) mice from three age groups using Laser-Doppler flowmetry. The rCBF response was reduced early in young 3xTgAD mice and almost absent in old 3xTgAD mice, up to 30%-40% reduction with altered CBF velocity and mean arterial pressure versus WT mice. The impaired rCBF response in 3xTgAD mice was associated with progression of AD pathology, characterized by deposition of intracellular and vascular amyloid-β (Aβ) oligomers, senile plaques and tau pathology. The nitric oxide synthase (NOS) inhibitor Nω-nitro-L-arginine abolished rCBF response to diazoxide suggesting NO was involved in the mediation of vasorelaxation. Levels of phosphor-eNOS (Ser1177) diminished in 3xTgAD brains with age, while the rCBF response to the NO donor sodium nitroprusside remained. In PS1M146V mice, the rCBF response to dizoxide reduced and high molecular weight Abeta oligomers were increased indicating PS1M146V contributed to the dysregulation of rCBF response in AD mice. Our study revealed an Aβ oligomer-associated compromise of cerebrovascular function in rCBF response to diazoxide in AD mice with PS1M146V mutation.
Collapse
Affiliation(s)
- Dong Liu
- Drug Design & Development Section, Translational Gerontology Branch, National Institute on Aging Intramural Research Program, Baltimore, MD, USA.,Laboratory of Neurosciences, National Institute on Aging Intramural Research Program, Baltimore, MD, USA
| | - Ismayil Ahmet
- Laboratory of Cardiovascular Science, National Institute on Aging Intramural Research Program, Baltimore, MD, USA
| | - Brandon Griess
- Laboratory of Neurosciences, National Institute on Aging Intramural Research Program, Baltimore, MD, USA
| | - David Tweedie
- Drug Design & Development Section, Translational Gerontology Branch, National Institute on Aging Intramural Research Program, Baltimore, MD, USA
| | - Nigel H Greig
- Drug Design & Development Section, Translational Gerontology Branch, National Institute on Aging Intramural Research Program, Baltimore, MD, USA
| | - Mark P Mattson
- Laboratory of Neurosciences, National Institute on Aging Intramural Research Program, Baltimore, MD, USA.,Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| |
Collapse
|
26
|
Jiang H, Wang J, Levin BE, Baumel BS, Camargo CJ, Signorile JF, Rundek T. Retinal Microvascular Alterations as the Biomarkers for Alzheimer Disease: Are We There Yet? J Neuroophthalmol 2021; 41:251-260. [PMID: 33136677 PMCID: PMC8079547 DOI: 10.1097/wno.0000000000001140] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
BACKGROUND Alzheimer disease (AD) is a heterogeneous and multifactorial disorder with an insidious onset and slowly progressive disease course. To date, there are no effective treatments, but biomarkers for early diagnosis and monitoring of disease progression offer a promising first step in developing and testing potential interventions. Cerebral vascular imaging biomarkers to assess the contributions of vascular dysfunction to AD are strongly recommended to be integrated into the current amyloid-β (Aβ) [A], tau [T], and neurodegeneration [(N)]-the "AT(N)" biomarker system for clinical research. However, the methodology is expensive and often requires invasive procedures to document cerebral vascular dysfunction. The retina has been used as a surrogate to study cerebral vascular changes. There is growing interest in the identification of retinal microvascular changes as a safe, easily accessible, low cost, and time-efficient approach to enhancing our understanding of the vascular pathogenesis associated with AD. EVIDENCE ACQUISITION A systemic review of the literature was performed regarding retinal vascular changes in AD and its prodromal stages, focusing on functional and structural changes of large retinal vessels (vessels visible on fundus photographs) and microvasculature (precapillary arterioles, capillary, and postcapillary venules) that are invisible on fundus photographs. RESULTS Static and dynamic retinal microvascular alterations such as retinal arterial wall motion, blood flow rate, and microvascular network density were reported in AD, mild cognitive impairment, and even in the preclinical stages of the disease. The data are somewhat controversial and inconsistent among the articles reviewed and were obtained based on cross-sectional studies that used different patient cohorts, equipment, techniques, and analysis methods. CONCLUSIONS Retinal microvascular alterations exist across the AD spectrum. Further large scale, within-subject longitudinal studies using standardized imaging and analytical methods may advance our knowledge concerning vascular contributions to the pathogenesis of AD.
Collapse
Affiliation(s)
- Hong Jiang
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Jianhua Wang
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Bonnie E. Levin
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Bernard S. Baumel
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Christian J. Camargo
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL, USA
| | | | - Tania Rundek
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL, USA
| |
Collapse
|
27
|
Gouveia-Freitas K, Bastos-Leite AJ. Perivascular spaces and brain waste clearance systems: relevance for neurodegenerative and cerebrovascular pathology. Neuroradiology 2021; 63:1581-1597. [PMID: 34019111 PMCID: PMC8460534 DOI: 10.1007/s00234-021-02718-7] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Accepted: 04/12/2021] [Indexed: 12/28/2022]
Abstract
Perivascular spaces (PVS) of the brain, often called Virchow-Robin spaces, comprise fluid, cells and connective tissue, and are externally limited by astrocytic endfeet. PVS are involved in clearing brain waste and belong to the "glymphatic" system and/or the "intramural periarterial drainage" pathway through the basement membranes of the arteries. Related brain waste clearance systems include the blood-brain barrier, scavenger cells, cerebrospinal fluid, perineural lymphatic drainage pathways and the newly characterised meningeal lymphatic vessels. Any functional abnormality of PVS or related clearance systems might lead to accumulation of brain waste. It has been postulated that PVS enlargement can be secondary to accumulation of β-amyloid. Lack of integrity of the vascular wall, microbleeds, cerebral amyloid angiopathy (CAA) and enlarged PVS often occur in the preclinical stages of Alzheimer's disease, preceding substantial brain atrophy. PVS enlargement in the form of état criblé at the basal ganglia has also been considered to reflect focal atrophy, most probably secondary to ischaemic injury, based upon both pathological and imaging arguments. In addition, distinct topographic patterns of enlarged PVS are related to different types of microangiopathy: CAA is linked to enlarged juxtacortical PVS, whereas subjects with vascular risk factors tend to have enlarged PVS in the basal ganglia. Therefore, enlarged PVS are progressively being regarded as a marker of neurodegenerative and cerebrovascular pathology. The present review addresses the evolving concept of PVS and brain waste clearance systems, the potential relevance of their dysfunction to neurodegenerative and cerebrovascular pathology, and potential therapeutic approaches of interest.
Collapse
Affiliation(s)
- Kaylene Gouveia-Freitas
- Faculty of Medicine, University of Porto, Alameda do Professor Hernâni Monteiro, 4200-319, Porto, Portugal
| | - António J Bastos-Leite
- Faculty of Medicine, University of Porto, Alameda do Professor Hernâni Monteiro, 4200-319, Porto, Portugal.
| |
Collapse
|
28
|
Attarpour A, Ward J, Chen JJ. Vascular origins of low-frequency oscillations in the cerebrospinal fluid signal in resting-state fMRI: Interpretation using photoplethysmography. Hum Brain Mapp 2021; 42:2606-2622. [PMID: 33638224 PMCID: PMC8090775 DOI: 10.1002/hbm.25392] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 02/09/2021] [Accepted: 02/16/2021] [Indexed: 12/12/2022] Open
Abstract
In vivo mapping of cerebrovascular oscillations in the 0.05–0.15 Hz remains difficult. Oscillations in the cerebrospinal fluid (CSF) represent a possible avenue for noninvasively tracking these oscillations using resting‐state functional MRI (rs‐fMRI), and have been used to correct for vascular oscillations in rs‐fMRI functional connectivity. However, the relationship between low‐frequency CSF and vascular oscillations remains unclear. In this study, we investigate this relationship using fast simultaneous rs‐fMRI and photoplethysmogram (PPG), examining the 0.1 Hz PPG signal, heart‐rate variability (HRV), pulse‐intensity ratio (PIR), and the second derivative of the PPG (SDPPG). The main findings of this study are: (a) signals in different CSF regions are not equivalent in their associations with vascular and tissue rs‐fMRI signals; (b) the PPG signal is maximally coherent with the arterial and CSF signals at the cardiac frequency, but coherent with brain tissue at ~0.2 Hz; (c) PIR is maximally coherent with the CSF signal near 0.03 Hz; and (d) PPG‐related vascular oscillations only contribute to ~15% of the CSF (and arterial) signal in rs‐fMRI. These findings caution against averaging all CSF regions when extracting physiological nuisance regressors in rs‐fMRI applications, and indicate the drivers of the CSF signal are more than simply cardiac. Our study is an initial attempt at the refinement and standardization of how the CSF signal in rs‐fMRI can be used and interpreted. It also paves the way for using rs‐fMRI in the CSF as a potential tool for tracking cerebrovascular health through, for instance, the potential relationship between PIR and the CSF signal.
Collapse
Affiliation(s)
- Ahmadreza Attarpour
- Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada
| | - James Ward
- Rotman Research Institute, Baycrest Health Sciences, Toronto, Ontario, Canada
| | - J Jean Chen
- Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada.,Rotman Research Institute, Baycrest Health Sciences, Toronto, Ontario, Canada
| |
Collapse
|
29
|
Nizari S, Wells JA, Carare RO, Romero IA, Hawkes CA. Loss of cholinergic innervation differentially affects eNOS-mediated blood flow, drainage of Aβ and cerebral amyloid angiopathy in the cortex and hippocampus of adult mice. Acta Neuropathol Commun 2021; 9:12. [PMID: 33413694 PMCID: PMC7791879 DOI: 10.1186/s40478-020-01108-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Accepted: 12/15/2020] [Indexed: 11/18/2022] Open
Abstract
Vascular dysregulation and cholinergic basal forebrain degeneration are both early pathological events in the development of Alzheimer’s disease (AD). Acetylcholine contributes to localised arterial dilatation and increased cerebral blood flow (CBF) during neurovascular coupling via activation of endothelial nitric oxide synthase (eNOS). Decreased vascular reactivity is suggested to contribute to impaired clearance of β-amyloid (Aβ) along intramural periarterial drainage (IPAD) pathways of the brain, leading to the development of cerebral amyloid angiopathy (CAA). However, the possible relationship between loss of cholinergic innervation, impaired vasoreactivity and reduced clearance of Aβ from the brain has not been previously investigated. In the present study, intracerebroventricular administration of mu-saporin resulted in significant death of cholinergic neurons and fibres in the medial septum, cortex and hippocampus of C57BL/6 mice. Arterial spin labelling MRI revealed a loss of CBF response to stimulation of eNOS by the Rho-kinase inhibitor fasudil hydrochloride in the cortex of denervated mice. By contrast, the hippocampus remained responsive to drug treatment, in association with altered eNOS expression. Fasudil hydrochloride significantly increased IPAD in the hippocampus of both control and saporin-treated mice, while increased clearance from the cortex was only observed in control animals. Administration of mu-saporin in the TetOAPPSweInd mouse model of AD was associated with a significant and selective increase in Aβ40-positive CAA. These findings support the importance of the interrelationship between cholinergic innervation and vascular function in the aetiology and/or progression of CAA and suggest that combined eNOS/cholinergic therapies may improve the efficiency of Aβ removal from the brain and reduce its deposition as CAA.
Collapse
|
30
|
Roy TK, Secomb TW. Effects of impaired microvascular flow regulation on metabolism-perfusion matching and organ function. Microcirculation 2020; 28:e12673. [PMID: 33236393 DOI: 10.1111/micc.12673] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Accepted: 11/17/2020] [Indexed: 12/14/2022]
Abstract
Impaired tissue oxygen delivery is a major cause of organ damage and failure in critically ill patients, which can occur even when systemic parameters, including cardiac output and arterial hemoglobin saturation, are close to normal. This review addresses oxygen transport mechanisms at the microcirculatory scale, and how hypoxia may occur in spite of adequate convective oxygen supply. The structure of the microcirculation is intrinsically heterogeneous, with wide variations in vessel diameters and flow pathway lengths, and consequently also in blood flow rates and oxygen levels. The dynamic processes of structural adaptation and flow regulation continually adjust microvessel diameters to compensate for heterogeneity, redistributing flow according to metabolic needs to ensure adequate tissue oxygenation. A key role in flow regulation is played by conducted responses, which are generated and propagated by endothelial cells and signal upstream arterioles to dilate in response to local hypoxia. Several pathophysiological conditions can impair local flow regulation, causing hypoxia and tissue damage leading to organ failure. Therapeutic measures targeted to systemic parameters may not address or may even worsen tissue oxygenation at the microvascular level. Restoration of tissue oxygenation in critically ill patients may depend on restoration of endothelial cell function, including conducted responses.
Collapse
Affiliation(s)
- Tuhin K Roy
- Department of Anesthesiology & Perioperative Medicine, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA
| | - Timothy W Secomb
- Department of Physiology, University of Arizona, Tucson, AZ, 85724, USA
| |
Collapse
|
31
|
Ribeiro VT, de Souza LC, Simões E Silva AC. Renin-Angiotensin System and Alzheimer's Disease Pathophysiology: From the Potential Interactions to Therapeutic Perspectives. Protein Pept Lett 2020; 27:484-511. [PMID: 31886744 DOI: 10.2174/0929866527666191230103739] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2019] [Revised: 08/27/2019] [Accepted: 11/16/2019] [Indexed: 12/21/2022]
Abstract
New roles of the Renin-Angiotensin System (RAS), apart from fluid homeostasis and Blood Pressure (BP) regulation, are being progressively unveiled, since the discoveries of RAS alternative axes and local RAS in different tissues, including the brain. Brain RAS is reported to interact with pathophysiological mechanisms of many neurological and psychiatric diseases, including Alzheimer's Disease (AD). Even though AD is the most common cause of dementia worldwide, its pathophysiology is far from elucidated. Currently, no treatment can halt the disease course. Successive failures of amyloid-targeting drugs have challenged the amyloid hypothesis and increased the interest in the inflammatory and vascular aspects of AD. RAS compounds, both centrally and peripherally, potentially interact with neuroinflammation and cerebrovascular regulation. This narrative review discusses the AD pathophysiology and its possible interaction with RAS, looking forward to potential therapeutic approaches. RAS molecules affect BP, cerebral blood flow, neuroinflammation, and oxidative stress. Angiotensin (Ang) II, via angiotensin type 1 receptors may promote brain tissue damage, while Ang-(1-7) seems to elicit neuroprotection. Several studies dosed RAS molecules in AD patients' biological material, with heterogeneous results. The link between AD and clinical conditions related to classical RAS axis overactivation (hypertension, heart failure, and chronic kidney disease) supports the hypothesized role of this system in AD. Additionally, RAStargeting drugs as Angiotensin Converting Enzyme inhibitors (ACEis) and Angiotensin Receptor Blockers (ARBs) seem to exert beneficial effects on AD. Results of randomized controlled trials testing ACEi or ARBs in AD are awaited to elucidate whether AD-RAS interaction has implications on AD therapeutics.
Collapse
Affiliation(s)
- Victor Teatini Ribeiro
- Interdisciplinary Laboratory of Medical Investigation, Faculty of Medicine, Federal University of Minas Gerais (UFMG), Belo Horizonte, Brazil
| | - Leonardo Cruz de Souza
- Interdisciplinary Laboratory of Medical Investigation, Faculty of Medicine, Federal University of Minas Gerais (UFMG), Belo Horizonte, Brazil.,Department of Internal Medicine, Service of Neurology, Faculty of Medicine, Federal University of Minas Gerais (UFMG), Belo Horizonte, Brazil
| | - Ana Cristina Simões E Silva
- Interdisciplinary Laboratory of Medical Investigation, Faculty of Medicine, Federal University of Minas Gerais (UFMG), Belo Horizonte, Brazil
| |
Collapse
|
32
|
Benveniste H, Elkin R, Heerdt PM, Koundal S, Xue Y, Lee H, Wardlaw J, Tannenbaum A. The glymphatic system and its role in cerebral homeostasis. J Appl Physiol (1985) 2020; 129:1330-1340. [PMID: 33002383 DOI: 10.1152/japplphysiol.00852.2019] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The brain's high bioenergetic state is paralleled by high metabolic waste production. Authentic lymphatic vasculature is lacking in brain parenchyma. Cerebrospinal fluid (CSF) flow has long been thought to facilitate central nervous system detoxification in place of lymphatics, but the exact processes involved in toxic waste clearance from the brain remain incompletely understood. Over the past 8 yr, novel data in animals and humans have begun to shed new light on these processes in the form of the "glymphatic system," a brain-wide perivascular transit passageway dedicated to CSF transport and interstitial fluid exchange that facilitates metabolic waste drainage from the brain. Here we will discuss glymphatic system anatomy and methods to visualize and quantify glymphatic system (GS) transport in the brain and also discuss physiological drivers of its function in normal brain and in neurodegeneration.
Collapse
Affiliation(s)
- Helene Benveniste
- Department of Anesthesiology, Yale School of Medicine, New Haven, Connecticut
| | - Rena Elkin
- Departments of Computer Science and Applied Mathematics & Statistics, Stony Brook University, Stony Brook, New York
| | - Paul M Heerdt
- Department of Anesthesiology, Yale School of Medicine, New Haven, Connecticut
| | - Sunil Koundal
- Department of Anesthesiology, Yale School of Medicine, New Haven, Connecticut
| | - Yuechuan Xue
- Department of Anesthesiology, Yale School of Medicine, New Haven, Connecticut
| | - Hedok Lee
- Department of Anesthesiology, Yale School of Medicine, New Haven, Connecticut
| | - Joanna Wardlaw
- Brain Research Imaging Centre, Centre for Clinical Brain Sciences, Dementia Research Institute at the University of Edinburgh, Edinburgh, United Kingdom
| | - Allen Tannenbaum
- Departments of Computer Science and Applied Mathematics & Statistics, Stony Brook University, Stony Brook, New York
| |
Collapse
|
33
|
Rivera-Rivera LA, Cody KA, Rutkowski D, Cary P, Eisenmenger L, Rowley HA, Carlsson CM, Johnson SC, Johnson KM. Intracranial vascular flow oscillations in Alzheimer's disease from 4D flow MRI. Neuroimage Clin 2020; 28:102379. [PMID: 32871386 PMCID: PMC7476069 DOI: 10.1016/j.nicl.2020.102379] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Revised: 07/10/2020] [Accepted: 08/07/2020] [Indexed: 11/26/2022]
Abstract
Recent modeling and experimental evidence suggests clearance of soluble metabolites from the brain can be driven by low frequency flow oscillations (LFOs) through the intramural periarterial drainage (IPAD) pathway. This study investigates the use of 4D flow MRI to derive LFOs from arterial and venous measures of blood flow. 3D radial 4D flow MRI data were acquired on a 3.0 T scanner and reconstructed using a low-rank constraint to produce time resolved measurements of blood flow. Physical phantom experiments were performed to validate the time resolved 4D flow against a standard 2D phase contrast (PC) approach. To evaluate the ability of 4D flow to distinguish physiologic flow changes from noise, healthy volunteers were scanned during a breath-hold (BH) maneuver and compared against 2D PC measures. Finally, flow measures were performed in intracranial arteries and veins of 112 participants including subjects diagnosed with Alzheimer's disease (AD) clinical syndrome (n = 23), and healthy controls (n = 89) on whom apolipoprotein ɛ4 positivity (APOE4+) and parental history of AD dementia (FH+) was known. To assess LFOs, flow range, standard deviation, demeaned temporal flow changes, and power spectral density were quantified from the time series. Group differences were assessed using ANOVA followed by Tukey-Kramer method for pairwise comparison for adjusted means (P < 0.05). Significantly lower LFOs as measured from flow variation range and standard deviations were observed in the arteries of AD subjects when compared to age-matched controls (P = 0.005, P = 0.011). Results suggest altered vascular function in AD subjects. 4D flow based spontaneous LFO measures might hold potential for longitudinal studies aimed at predicting cognitive trajectories in AD and study disease mechanisms.
Collapse
Affiliation(s)
- Leonardo A Rivera-Rivera
- Department of Medical Physics, University of Wisconsin, School of Medicine and Public Health, Madison, WI, USA
| | - Karly A Cody
- Alzheimer's Disease Research Center, University of Wisconsin, School of Medicine and Public Health, Madison, WI, USA
| | - David Rutkowski
- Department of Radiology, University of Wisconsin, School of Medicine and Public Health, Madison, WI, USA
| | - Paul Cary
- Alzheimer's Disease Research Center, University of Wisconsin, School of Medicine and Public Health, Madison, WI, USA
| | - Laura Eisenmenger
- Department of Radiology, University of Wisconsin, School of Medicine and Public Health, Madison, WI, USA
| | - Howard A Rowley
- Alzheimer's Disease Research Center, University of Wisconsin, School of Medicine and Public Health, Madison, WI, USA; Department of Radiology, University of Wisconsin, School of Medicine and Public Health, Madison, WI, USA
| | - Cynthia M Carlsson
- Alzheimer's Disease Research Center, University of Wisconsin, School of Medicine and Public Health, Madison, WI, USA; Geriatric Research Education and Clinical Center, William S. Middleton Memorial Veterans Hospital, Madison, WI, USA
| | - Sterling C Johnson
- Alzheimer's Disease Research Center, University of Wisconsin, School of Medicine and Public Health, Madison, WI, USA; Geriatric Research Education and Clinical Center, William S. Middleton Memorial Veterans Hospital, Madison, WI, USA
| | - Kevin M Johnson
- Department of Medical Physics, University of Wisconsin, School of Medicine and Public Health, Madison, WI, USA; Department of Radiology, University of Wisconsin, School of Medicine and Public Health, Madison, WI, USA.
| |
Collapse
|
34
|
Goodman JR, Iliff JJ. Vasomotor influences on glymphatic-lymphatic coupling and solute trafficking in the central nervous system. J Cereb Blood Flow Metab 2020; 40:1724-1734. [PMID: 31506012 PMCID: PMC7370362 DOI: 10.1177/0271678x19874134] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Despite the recent description of meningeal lymphatic vessels draining solutes from the brain interstitium and cerebrospinal fluid (CSF), the physiological factors governing cranial lymphatic efflux remain largely unexplored. In agreement with recent findings, cervical lymphatic drainage of 70 kD and 2000 kD fluorescent tracers injected into the adult mouse cortex was significantly impaired in the anesthetized compared to waking animals (tracer distribution across 2.1 ± 4.5% and 23.7 ± 15.8% of deep cervical lymph nodes, respectively); however, free-breathing anesthetized mice were markedly hypercapnic and acidemic (paCO2 = 64 ± 8 mmHg; pH = 7.22 ± 0.05). Mechanical ventilation normalized arterial blood gases in anesthetized animals, and rescued lymphatic efflux of interstitial solutes in anesthetized mice. Experimental hypercapnia blocked cervical lymphatic efflux of intraparenchymal tracers. When tracers were injected into the subarachnoid CSF compartment, glymphatic influx into brain tissue was virtually abolished by hypercapnia, while lymphatic drainage was not appreciably altered. These findings demonstrate that cervical lymphatic drainage of interstitial solutes is, in part, regulated by upstream changes in glymphatic CSF-interstitial fluid exchange. Further, they suggest that maintaining physiological blood gas values in studies of glymphatic exchange and meningeal lymphatic drainage may be critical to defining the physiological regulation of these processes.
Collapse
Affiliation(s)
- James R Goodman
- Department of Anesthesiology and Perioperative Medicine, Oregon Health & Science University, Portland, OR, USA.,Department of Physiology and Pharmacology, Oregon Health & Science University, Portland, OR, USA
| | - Jeffrey J Iliff
- Department of Anesthesiology and Perioperative Medicine, Oregon Health & Science University, Portland, OR, USA.,Knight Cardiovascular Institute, Oregon Health & Science University, Portland, OR, USA
| |
Collapse
|
35
|
Ghali MGZ, Marchenko V, Yaşargil MG, Ghali GZ. Structure and function of the perivascular fluid compartment and vertebral venous plexus: Illumining a novel theory on mechanisms underlying the pathogenesis of Alzheimer's, cerebral small vessel, and neurodegenerative diseases. Neurobiol Dis 2020; 144:105022. [PMID: 32687942 DOI: 10.1016/j.nbd.2020.105022] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2020] [Revised: 06/13/2020] [Accepted: 07/15/2020] [Indexed: 01/14/2023] Open
Abstract
Blood dynamically and richly supplies the cerebral tissue via microvessels invested in pia matter perforating the cerebral substance. Arteries penetrating the cerebral substance derive an investment from one or two successive layers of pia mater, luminally apposed to the pial-glial basal lamina of the microvasculature and abluminally apposed to a series of aquaporin IV-studded astrocytic end feet constituting the soi-disant glia limitans. The full investment of successive layers forms the variably continuous walls of the periarteriolar, pericapillary, and perivenular divisions of the perivascular fluid compartment. The pia matter disappears at the distal periarteriolar division of the perivascular fluid compartment. Plasma from arteriolar blood sequentially transudates into the periarteriolar division of the perivascular fluid compartment and subarachnoid cisterns in precession to trickling into the neural interstitium. Fluid from the neural interstitium successively propagates into the venules through the subarachnoid cisterns and perivenular division of the perivascular fluid compartment. Fluid fluent within the perivascular fluid compartment flows gegen the net direction of arteriovenular flow. Microvessel oscillations at the central tendency of the cerebral vasomotion generate corresponding oscillations of within the surrounding perivascular fluid compartment, interposed betwixt the abluminal surface of the vessels and internal surface of the pia mater. The precise microanatomy of this most fascinating among designable spaces has eluded the efforts of various investigators to interrogate its structure, though most authors non-consensusly concur the investing layers effectively and functionally segregate the perivascular and subarachnoid fluid compartments. Enlargement of the perivascular fluid compartment in a variety of neurological disorders, including senile dementia of the Alzheimer's type and cerebral small vessel disease, may alternately or coordinately constitute a correlative marker of disease severity and a possible cause implicated in the mechanistic pathogenesis of these conditions. Venular pressures modulating oscillatory dynamic flow within the perivascular fluid compartment may similarly contribute to the development of a variety among neurological disorders. An intimate understanding of subtle features typifying microanatomy and microphysiology of the investing structures and spaces of the cerebral microvasculature may powerfully inform mechanistic pathophysiology mediating a variety of neurovascular ischemic, neuroinfectious, neuroautoimmune, and neurodegenerative diseases.
Collapse
Affiliation(s)
- Michael George Zaki Ghali
- Department of Neurological Surgery, University of California San Francisco, 505 Parnassus Street, San Francisco, CA 94143, United States; Department of Neurobiology and Anatomy, 2900 W. Queen Lane, Philadelphia, PA 19129, United States.
| | - Vitaliy Marchenko
- Department of Neurobiology and Anatomy, 2900 W. Queen Lane, Philadelphia, PA 19129, United States; Department of Neurophysiology, Bogomoletz Institute, Kyiv, Ukraine; Department of Neuroscience, Московский государственный университет имени М. В., Ломоносова GSP-1, Leninskie Gory, Moscow 119991, Russian Federation
| | - M Gazi Yaşargil
- Department of Neurosurgery, University Hospital Zurich Rämistrasse 100, 8091 Zurich, Switzerland
| | - George Zaki Ghali
- United States Environmental Protection Agency, Arlington, Virginia, USA; Emeritus Professor of Toxicology, Purdue University, West Lafayette, Indiana, USA
| |
Collapse
|
36
|
Abstract
PURPOSE To review the recent developments on the effect of chronic high mean arterial blood pressure (MAP) on cerebral blood flow (CBF) autoregulation and supporting the notion that CBF autoregulation impairment has connection with chronic cerebral diseases. Method: A narrative review of all the relevant papers known to the authors was conducted. Results: Our understanding of the connection between cerebral perfusion impairment and chronic high MAP and cerebral disease is rapidly evolving, from cerebral perfusion impairment being the result of cerebral diseases to being the cause of cerebral diseases. We now better understand the intertwined impact of hypertension and Alzheimer's disease (AD) on cerebrovascular sensory elements and recognize cerebrovascular elements that are more vulnerable to these diseases. Conclusion: We conclude with the suggestion that the sensory elements pathology plays important roles in intertwined mechanisms of chronic high MAP and AD that impact cerebral perfusion.
Collapse
Affiliation(s)
- Noushin Yazdani
- College of Public Health, University of South Florida , Tampa, FL, USA
| | - Mark S Kindy
- Department of Pharmaceutical Sciences, College of Pharmacy, University of South Florida , Tampa, FL, USA.,Biomedical Research, James A. Haley VA Medical Center , Tampa, FL, USA
| | - Saeid Taheri
- Department of Pharmaceutical Sciences, College of Pharmacy, University of South Florida , Tampa, FL, USA.,Byrd Neuroscience Institute, University of South Florida , Tampa, FL, USA
| |
Collapse
|
37
|
Pei H, Ma L, Cao Y, Wang F, Li Z, Liu N, Liu M, Wei Y, Li H. Traditional Chinese Medicine for Alzheimer's Disease and Other Cognitive Impairment: A Review. THE AMERICAN JOURNAL OF CHINESE MEDICINE 2020; 48:487-511. [PMID: 32329645 DOI: 10.1142/s0192415x20500251] [Citation(s) in RCA: 83] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Cognitive impairment (CI) refers to the dysfunction of memory, language, visual space, execution, calculation, understanding, and judgment in one or more aspects. With global aging, CI will become prevalent worldwide. At present, there is no effective cure for CI. However, Nobel laureate Tu Youyou's research on artemisinin has inspired Chinese researchers to focus on traditional Chinese herbs (TCHs) for the treatment of CI. Traditional Chinese Medicine (TCM) has led to a theory for an independent CI system. The pathogenesis of such impairment involves deficiency, phlegm, and stagnation and involves a range of organs, including the brain, kidneys, heart, liver, and spleen. Our current understanding of the etiology and pathogenesis of this condition has led to the realization that TCHs can improve cognitive dysfunction. Clinical research has shown that TCHs can improve the neuropsychological scale score of patients, the TCM symptom score, and the patient's quality of life. Research has also suggested that TCHs can retard Aβ deposits and tauopathy, regulate the metabolism of cholinergic neurotransmitters, and so on. However, due to their complexity, little is known of the safety and efficacy of TCHs in patients with CI. It is likely that we will be able to identify the precise mechanisms associated with the action of TCHs in such patients due to the integration of multiple technologies. This paper summarizes the pharmacokinetics, curative effect, and mechanisms of action of traditional Chinese herbs in order to provide a scientific basis for the improvement of cognitive dysfunction by TCHs.
Collapse
Affiliation(s)
- Hui Pei
- Institude of Geriatrics, Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing 100091, P. R. China
| | - Lina Ma
- Institude of Geriatrics, Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing 100091, P. R. China
| | - Yu Cao
- Institude of Geriatrics, Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing 100091, P. R. China
| | - Feixue Wang
- Traditional Chinese Medicine Department, Xuanwu Hospital Capital Medical University, Beijing 100053, P. R. China
| | - Zehui Li
- Institude of Geriatrics, Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing 100091, P. R. China
| | - Nanyang Liu
- Institude of Geriatrics, Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing 100091, P. R. China
| | - Meixia Liu
- Institude of Geriatrics, Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing 100091, P. R. China
| | - Yun Wei
- Institude of Geriatrics, Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing 100091, P. R. China
| | - Hao Li
- Institude of Geriatrics, Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing 100091, P. R. China
| |
Collapse
|
38
|
Ghali MGZ, Styler MJ. Etiologies, Cerebral Vasomotion, and Endothelial Dysfunction in the Pathophysiology of Posterior Reversible Encephalopathy Syndrome in Pediatric Patients. JOURNAL OF PEDIATRIC NEUROLOGY 2020. [DOI: 10.1055/s-0040-1702934] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
AbstractThe posterior reversible encephalopathy syndrome was characterized by Hinchey and colleagues in the 1990s. The condition frequently afflicts patients suffering from hematologic and solid organ malignancy and individuals undergoing transplantation. Cases are more frequently described in the adult population compared with children. In the pediatric population, malignancy, transplantation, renal disease, and hypertension represent the most common etiologies. Theories on pathogenesis have centered upon cerebrovascular dysautoregulation with increases in blood–brain barrier permeability. This generates vasogenic edema of the cerebral parenchyma and consequent neurologic deficits. The parietal and occipital lobes are affected with greatest prevalence, though frontal and temporal lobe involvement is frequent, and that of the contents of the infratentorial posterior cranial fossa are occasionally described. The clinical presentation involves a characteristic constellation of neurologic signs and symptoms, most typically inclusive of headache, visual-field disturbances, abnormalities of visual acuity, and seizures. Supportive care, withdrawal of the offending agent, antihypertensive therapy, and prophylactic anticonvulsants affect convalescence in majority of cases. The principal challenge lies in identifying the responsible agent precipitating the condition in patients with malignancy and those having undergone transplantation and thus deciding which medication among a multidrug treatment regimen to withhold, the duration of drug cessation required to effect clinical resolution, and the safety of resuming treatment with the compound. We accordingly reviewed and evaluated the literature discussing the posterior reversible encephalopathy syndrome in children.
Collapse
Affiliation(s)
- Michael G. Z. Ghali
- Department of Neurological Surgery, Houston Methodist Hospital, Houston, Texas, United States
| | - Michael J. Styler
- Department of Hematology and Oncology, Hahnemann University Hospital, Philadelphia, Pennsylvania, United States
| |
Collapse
|
39
|
Denver P, D’Adamo H, Hu S, Zuo X, Zhu C, Okuma C, Kim P, Castro D, Jones MR, Leal C, Mekkittikul M, Ghadishah E, Teter B, Vinters HV, Cole GM, Frautschy SA. A Novel Model of Mixed Vascular Dementia Incorporating Hypertension in a Rat Model of Alzheimer's Disease. Front Physiol 2019; 10:1269. [PMID: 31708792 PMCID: PMC6821690 DOI: 10.3389/fphys.2019.01269] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Accepted: 09/19/2019] [Indexed: 02/06/2023] Open
Abstract
Alzheimer's disease (AD) and mixed dementia (MxD) comprise the majority of dementia cases in the growing global aging population. MxD describes the coexistence of AD pathology with vascular pathology, including cerebral small vessel disease (SVD). Cardiovascular disease increases risk for AD and MxD, but mechanistic synergisms between the coexisting pathologies affecting dementia risk, progression and the ultimate clinical manifestations remain elusive. To explore the additive or synergistic interactions between AD and chronic hypertension, we developed a rat model of MxD, produced by breeding APPswe/PS1ΔE9 transgenes into the stroke-prone spontaneously hypertensive rat (SHRSP) background, resulting in the SHRSP/FAD model and three control groups (FAD, SHRSP and non-hypertensive WKY rats, n = 8-11, both sexes, 16-18 months of age). After behavioral testing, rats were euthanized, and tissue assessed for vascular, neuroinflammatory and AD pathology. Hypertension was preserved in the SHRSP/FAD cross. Results showed that SHRSP increased FAD-dependent neuroinflammation (microglia and astrocytes) and tau pathology, but plaque pathology changes were subtle, including fewer plaques with compact cores and slightly reduced plaque burden. Evidence for vascular pathology included a change in the distribution of astrocytic end-foot protein aquaporin-4, normally distributed in microvessels, but in SHRSP/FAD rats largely dissociated from vessels, appearing disorganized or redistributed into neuropil. Other evidence of SVD-like pathology included increased collagen IV staining in cerebral vessels and PECAM1 levels. We identified a plasma biomarker in SHRSP/FAD rats that was the only group to show increased Aqp-4 in plasma exosomes. Evidence of neuron damage in SHRSP/FAD rats included increased caspase-cleaved actin, loss of myelin and reduced calbindin staining in neurons. Further, there were mitochondrial deficits specific to SHRSP/FAD, notably the loss of complex II, accompanying FAD-dependent loss of mitochondrial complex I. Cognitive deficits exhibited by FAD rats were not exacerbated by the introduction of the SHRSP phenotype, nor was the hyperactivity phenotype associated with SHRSP altered by the FAD transgene. This novel rat model of MxD, encompassing an amyloidogenic transgene with a hypertensive phenotype, exhibits several features associated with human vascular or "mixed" dementia and may be a useful tool in delineating the pathophysiology of MxD and development of therapeutics.
Collapse
Affiliation(s)
- Paul Denver
- Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
| | - Heather D’Adamo
- Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
- Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, CA, United States
- Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
| | - Shuxin Hu
- Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
- Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, CA, United States
- Geriatric Research Education and Clinical Center, Greater Los Angeles Veterans Affairs Healthcare System, Los Angeles, CA, United States
| | - Xiaohong Zuo
- Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
- Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, CA, United States
- Geriatric Research Education and Clinical Center, Greater Los Angeles Veterans Affairs Healthcare System, Los Angeles, CA, United States
| | - Cansheng Zhu
- Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
- Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, CA, United States
| | - Chihiro Okuma
- Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
- Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, CA, United States
| | - Peter Kim
- Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
- Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, CA, United States
- Geriatric Research Education and Clinical Center, Greater Los Angeles Veterans Affairs Healthcare System, Los Angeles, CA, United States
| | - Daniel Castro
- Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
- Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, CA, United States
| | - Mychica R. Jones
- Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
- Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, CA, United States
| | - Carmen Leal
- Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
- Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, CA, United States
- Geriatric Research Education and Clinical Center, Greater Los Angeles Veterans Affairs Healthcare System, Los Angeles, CA, United States
| | - Marisa Mekkittikul
- Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
- Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, CA, United States
- Geriatric Research Education and Clinical Center, Greater Los Angeles Veterans Affairs Healthcare System, Los Angeles, CA, United States
| | - Elham Ghadishah
- Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
- Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, CA, United States
- Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
| | - Bruce Teter
- Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
- Geriatric Research Education and Clinical Center, Greater Los Angeles Veterans Affairs Healthcare System, Los Angeles, CA, United States
| | - Harry V. Vinters
- Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
- Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, CA, United States
| | - Gregory Michael Cole
- Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
- Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, CA, United States
- Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
- Geriatric Research Education and Clinical Center, Greater Los Angeles Veterans Affairs Healthcare System, Los Angeles, CA, United States
| | - Sally A. Frautschy
- Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
- Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, CA, United States
- Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
- Geriatric Research Education and Clinical Center, Greater Los Angeles Veterans Affairs Healthcare System, Los Angeles, CA, United States
| |
Collapse
|
40
|
Tamura R, Yoshida K, Toda M. Current understanding of lymphatic vessels in the central nervous system. Neurosurg Rev 2019; 43:1055-1064. [PMID: 31209659 DOI: 10.1007/s10143-019-01133-0] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Revised: 04/29/2019] [Accepted: 06/05/2019] [Indexed: 12/18/2022]
Abstract
Lymphangiogenesis is associated with some pathological conditions such as inflammation, tissue repair, and tumor growth. Recently, a paradigm shift occurred following the discovery of meningeal lymphatic structures in the human central nervous system (CNS); these structures may be a key drainage route for cerebrospinal fluid (CSF) into the peripheral blood and may also contribute to inflammatory reaction and immune surveillance of the CNS. Lymphatic vessels located along the dural sinuses absorb CSF from the adjacent subarachnoid space and brain interstitial fluid via the glymphatic system, which is composed of aquaporin-4 water channels expressed on perivascular astrocytic end-feet membranes. Magnetic resonance imaging (MRI) clearly visualized these lymphatic vessels in the human dura mater. The conception of some neurological disorders, such as multiple sclerosis and Alzheimer's disease, has been changed by this paradigm shift. Meningeal lymphatic vessels could be a promising therapeutic target for the prevention of neurological disorders. However, the involvement of meningeal lymphatic vessels in the pathophysiology has not been fully elucidated and is the subject of future investigations. In this article, to understand the involvement of meningeal lymphatic vessels in neurological disorders, we review the differences between lymphangiogenesis in the CNS and in other tissues during both developmental and adulthood stages, and pathological conditions that may be associated with meningeal lymphatic vessels in the CNS.
Collapse
Affiliation(s)
- Ryota Tamura
- Department of Neurosurgery, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo, 160-8582, Japan
| | - Kazunari Yoshida
- Department of Neurosurgery, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo, 160-8582, Japan
| | - Masahiro Toda
- Department of Neurosurgery, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo, 160-8582, Japan.
| |
Collapse
|
41
|
McAleese KE, Graham S, Dey M, Walker L, Erskine D, Johnson M, Johnston E, Thomas AJ, McKeith IG, DeCarli C, Attems J. Extravascular fibrinogen in the white matter of Alzheimer's disease and normal aged brains: implications for fibrinogen as a biomarker for Alzheimer's disease. Brain Pathol 2019; 29:414-424. [PMID: 30485582 PMCID: PMC8028661 DOI: 10.1111/bpa.12685] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Accepted: 11/16/2018] [Indexed: 12/11/2022] Open
Abstract
The blood-brain barrier (BBB) regulates cerebrovascular permeability and leakage of blood-derived fibrinogen. Dysfunction of the BBB has been associated with cerebral arteriolosclerosis small vessel disease (SVD) and white matter lesions (WML). Furthermore, BBB dysfunction is associated with the pathogenesis of Alzheimer's disease (AD) with the presence of CSF plasma proteins suggested to be a potential biomarker of AD. We aimed to determine if extravascular fibrinogen in the white matter was associated with the development of AD hallmark pathologies, i.e., hyperphosphorylated tau (HPτ) and amyloid-β (Aβ), as well as SVD, cerebral amyloid angiopathy (CAA) and measures of white matter damage. Using human post-mortem brains, parietal tissue from 20 AD and 22 non-demented controls was quantitatively assessed for HPτ, Aβ, white matter damage severity, axonal density, demyelination and the burden of extravascular fibrinogen in both WML and normal appearing white matter (NAWM). SVD severity was determined by calculating sclerotic indices. WML- and NAWM fibrinogen burden was not significantly different between AD and controls nor was it associated with the burden of HPτ or Aβ pathology, or any measures of white matter damage. Increasing severity of SVD was associated with and a predictor of both higher WML- and NAWM fibrinogen burden (all P < 0.05) in controls only. In cases with minimal SVD NAWM fibrinogen burden was significantly higher in the AD cases (P < 0.05). BBB dysfunction was present in both non-demented and AD brains and was not associated with the burden of AD-associated cortical pathologies. BBB dysfunction was strongly associated with SVD but only in the non-demented controls. In cases with minimal SVD, BBB dysfunction was significantly worse in AD cases possibly indicating the influence of CAA. In conclusion, extravascular fibrinogen is not associated with AD hallmark pathologies but indicates SVD, suggesting that the presence of fibrinogen in the CSF is not a surrogate marker for AD pathology.
Collapse
Affiliation(s)
| | - Sophie Graham
- Institute of NeuroscienceNewcastle UniversityNewcastle Upon TyneUK
| | | | - Lauren Walker
- Institute of NeuroscienceNewcastle UniversityNewcastle Upon TyneUK
| | - Daniel Erskine
- Institute of NeuroscienceNewcastle UniversityNewcastle Upon TyneUK
| | - Mary Johnson
- Institute of NeuroscienceNewcastle UniversityNewcastle Upon TyneUK
| | - Eleanor Johnston
- Institute of NeuroscienceNewcastle UniversityNewcastle Upon TyneUK
| | - Alan J. Thomas
- Institute of NeuroscienceNewcastle UniversityNewcastle Upon TyneUK
| | - Ian G. McKeith
- Institute of NeuroscienceNewcastle UniversityNewcastle Upon TyneUK
| | | | - Johannes Attems
- Institute of NeuroscienceNewcastle UniversityNewcastle Upon TyneUK
| |
Collapse
|
42
|
Retinal capillary perfusion: Spatial and temporal heterogeneity. Prog Retin Eye Res 2019; 70:23-54. [PMID: 30769149 DOI: 10.1016/j.preteyeres.2019.01.001] [Citation(s) in RCA: 84] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Revised: 01/18/2019] [Accepted: 01/19/2019] [Indexed: 01/17/2023]
Abstract
The central role of the cardiovascular system is to maintain adequate capillary perfusion. The spatially and temporally heterogeneous nature of capillary perfusion has been reported in some organs. However, such heterogeneous perfusion properties have not been sufficiently explored in the retina. Arguably, spatial and temporal heterogeneity of capillary perfusion could be more predominant in the retina than that in other organs. This is because the retina is one of the highest metabolic demand neural tissues yet it has a limited blood supply due to optical requirements. In addition, the unique heterogeneous distribution of retinal neural cells within different layers and regions, and the significant heterogeneity of intraretinal oxygen distribution and consumption add to the complexity. Retinal blood flow distribution must match consumption of nutrients such as oxygen and glucose within the retina at the cellular level in order to effectively maintain cell survival and function. Sophisticated local blood flow control in the microcirculation is likely required to control the retinal capillary perfusion to supply local retinal tissue and accommodate temporal and spatial variations in metabolic supply and demand. The authors would like to update the knowledge of the retinal microvessel and capillary network and retinal oxidative metabolism from their own studies and the work of others. The coupling between blood supply and energy demands in the retina is particularly interesting. We will mostly describe information regarding the retinal microvessel network and retinal oxidative metabolism relevant to the spatial and temporal heterogeneity of capillary perfusion. We believe that there is significant and necessary spatial and temporal heterogeneity and active regulation of retinal blood flow in the retina, particularly in the macular region. Recently, retinal optical coherence tomography angiography (OCTA) has been widely used in ophthalmology, both experimentally and clinically. OCTA could be a valuable tool for examining retinal microvessel and capillary network structurally and has potential for determining retinal capillary perfusion and its control. We have demonstrated spatial and temporal heterogeneity of capillary perfusion in the retina both experimentally and clinically. We have also found close relationships between the smallest arterioles and capillaries within paired arterioles and venules and determined the distribution of smooth muscle cell contraction proteins in these vessels. Spatial and temporal heterogeneity of retinal capillary perfusion could be a useful parameter to determine retinal microvessel regulatory capability as an early assay for retinal vascular diseases. This topic will be of great interest, not only for the eye but also other organs. The retina could be the best model for such investigations. Unlike cerebral vessels, retinal vessels can be seen even at the capillary level. The purpose of this manuscript is to share our current understanding with the readers and encourage more researchers and clinicians to investigate this field. We begin by reviewing the general principles of microcirculation properties and the spatial and temporal heterogeneity of the capillary perfusion in other organs, before considering the special requirements of the retina. The local heterogeneity of oxygen supply and demand in the retina and the need to have a limited and well-regulated retinal circulation to preserve the transparency of the retina is discussed. We then consider how such a delicate balance of metabolic supply and consumption is achieved. Finally we discuss how new imaging methodologies such as optical coherence tomography angiography may be able to detect the presence of spatial and temporal heterogeneity of capillary perfusion in a clinical setting. We also provide some new information of the control role of very small arterioles in the modulation of retinal capillary perfusion which could be an interesting topic for further investigation.
Collapse
|
43
|
Aldea R, Weller RO, Wilcock DM, Carare RO, Richardson G. Cerebrovascular Smooth Muscle Cells as the Drivers of Intramural Periarterial Drainage of the Brain. Front Aging Neurosci 2019; 11:1. [PMID: 30740048 PMCID: PMC6357927 DOI: 10.3389/fnagi.2019.00001] [Citation(s) in RCA: 133] [Impact Index Per Article: 26.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2018] [Accepted: 01/07/2019] [Indexed: 12/25/2022] Open
Abstract
The human brain is the organ with the highest metabolic activity but it lacks a traditional lymphatic system responsible for clearing waste products. We have demonstrated that the basement membranes of cerebral capillaries and arteries represent the lymphatic pathways of the brain along which intramural periarterial drainage (IPAD) of soluble metabolites occurs. Failure of IPAD could explain the vascular deposition of the amyloid-beta protein as cerebral amyloid angiopathy (CAA), which is a key pathological feature of Alzheimer's disease. The underlying mechanisms of IPAD, including its motive force, have not been clarified, delaying successful therapies for CAA. Although arterial pulsations from the heart were initially considered to be the motive force for IPAD, they are not strong enough for efficient IPAD. This study aims to unravel the driving force for IPAD, by shifting the perspective of a heart-driven clearance of soluble metabolites from the brain to an intrinsic mechanism of cerebral arteries (e.g., vasomotion-driven IPAD). We test the hypothesis that the cerebrovascular smooth muscle cells, whose cycles of contraction and relaxation generate vasomotion, are the drivers of IPAD. A novel multiscale model of arteries, in which we treat the basement membrane as a fluid-filled poroelastic medium deformed by the contractile cerebrovascular smooth muscle cells, is used to test the hypothesis. The vasomotion-induced intramural flow rates suggest that vasomotion-driven IPAD is the only mechanism postulated to date capable of explaining the available experimental observations. The cerebrovascular smooth muscle cells could represent valuable drug targets for prevention and early interventions in CAA.
Collapse
Affiliation(s)
- Roxana Aldea
- Mathematical Sciences, University of Southampton, Southampton, United Kingdom
| | - Roy O Weller
- Clinical Neurosciences, Faculty of Medicine, University of Southampton, Southampton General Hospital, Southampton, United Kingdom
| | - Donna M Wilcock
- Department of Physiology, Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, United States
| | - Roxana O Carare
- Clinical Neurosciences, Faculty of Medicine, University of Southampton, Southampton General Hospital, Southampton, United Kingdom
| | - Giles Richardson
- Mathematical Sciences, University of Southampton, Southampton, United Kingdom
| |
Collapse
|
44
|
Letra L, Rodrigues T, Matafome P, Santana I, Seiça R. Adiponectin and sporadic Alzheimer's disease: Clinical and molecular links. Front Neuroendocrinol 2019; 52:1-11. [PMID: 29038028 DOI: 10.1016/j.yfrne.2017.10.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Revised: 09/05/2017] [Accepted: 10/10/2017] [Indexed: 01/21/2023]
Abstract
Obesity has been consistently associated with Alzheimer's disease (AD) though the exact mechanisms by which it influences cognition are still elusive and subject of current research. Adiponectin, the most abundant adipokine in circulation, is inversely correlated with adipose tissue dysfunction and seems to be a central player in this association. In fact, different signalling pathways are shared by adiponectin and proteins involved in AD pathophysiology and considerable amount of evidence supports its direct and indirect influence on β-amyloid and tau aggregates formation. In this paper we present a critical review of cellular, animal and clinical studies which have contributed to a more thorough understanding of the extent to which adiponectin influences the risk of developing AD as well as its progression. Finally, the effect of acetylcholinesterase inhibitors on circulating adiponectin levels, possible therapeutic applications and future research strategies are also discussed.
Collapse
Affiliation(s)
- Liliana Letra
- Institute of Physiology, Institute for Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, Azinhaga de Santa Comba, 3000-548 Coimbra, Portugal; Neurology Department, Centro Hospitalar do Baixo Vouga - Aveiro, Av. Artur Ravara, 3814-501 Aveiro, Portugal.
| | - Tiago Rodrigues
- Institute of Physiology, Institute for Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, Azinhaga de Santa Comba, 3000-548 Coimbra, Portugal.
| | - Paulo Matafome
- Institute of Physiology, Institute for Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, Azinhaga de Santa Comba, 3000-548 Coimbra, Portugal.
| | - Isabel Santana
- Neurology Department, Centro Hospitalar e Universitário de Coimbra, Praceta Professor Mota Pinto, 3000-075 Coimbra, Portugal; Faculty of Medicine, University of Coimbra, Azinhaga de Santa Comba, 3000-548 Coimbra, Portugal; CNC, Center for Neuroscience and Cell Biology, University of Coimbra, Azinhaga de Santa Comba, 3000-548 Coimbra, Portugal.
| | - Raquel Seiça
- Institute of Physiology, Institute for Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, Azinhaga de Santa Comba, 3000-548 Coimbra, Portugal.
| |
Collapse
|
45
|
Cellular and Ionic Mechanisms of Arterial Vasomotion. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1124:297-312. [DOI: 10.1007/978-981-13-5895-1_12] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
|
46
|
Chakraborty A, Kamermans A, van het Hof B, Castricum K, Aanhane E, van Horssen J, Thijssen VL, Scheltens P, Teunissen CE, Fontijn RD, van der Flier WM, de Vries HE. Angiopoietin like-4 as a novel vascular mediator in capillary cerebral amyloid angiopathy. Brain 2018; 141:3377-3388. [DOI: 10.1093/brain/awy274] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Accepted: 09/13/2018] [Indexed: 12/15/2022] Open
Affiliation(s)
- Ananya Chakraborty
- Amsterdam UMC, Vrije Universiteit Amsterdam, Department of Molecular Cell Biology and Immunology, Amsterdam Neuroscience, The Netherlands
| | - Alwin Kamermans
- Amsterdam UMC, Vrije Universiteit Amsterdam, Department of Molecular Cell Biology and Immunology, Amsterdam Neuroscience, The Netherlands
| | - Bert van het Hof
- Amsterdam UMC, Vrije Universiteit Amsterdam, Department of Molecular Cell Biology and Immunology, Amsterdam Neuroscience, The Netherlands
| | - Kitty Castricum
- Amsterdam UMC, Vrije Universiteit Amsterdam, Department of Radiation Oncology, The Netherlands
| | - Ed Aanhane
- Amsterdam UMC, Vrije Universiteit Amsterdam, Department of Radiation Oncology, The Netherlands
| | - Jack van Horssen
- Amsterdam UMC, Vrije Universiteit Amsterdam, Department of Molecular Cell Biology and Immunology, Amsterdam Neuroscience, The Netherlands
| | - Victor L Thijssen
- Amsterdam UMC, Vrije Universiteit Amsterdam, Department of Radiation Oncology, The Netherlands
| | - Philip Scheltens
- Amsterdam UMC, Vrije Universiteit Amsterdam, Alzheimer Center and Department of Neurology, Amsterdam Neuroscience, The Netherlands
| | - Charlotte E Teunissen
- Amsterdam UMC, Vrije Universiteit Amsterdam, Neurochemistry Lab and Biobank, Department of Clinical Chemistry, The Netherlands
| | - Ruud D Fontijn
- Amsterdam UMC, Vrije Universiteit Amsterdam, Department of Molecular Cell Biology and Immunology, Amsterdam Neuroscience, The Netherlands
| | - Wiesje M van der Flier
- Amsterdam UMC, Vrije Universiteit Amsterdam, Department of Radiation Oncology, The Netherlands
- Amsterdam UMC, Vrije Universiteit Amsterdam, Department of Epidemiology and Biostatistics, Amsterdam Neuroscience, The Netherlands
| | - Helga E de Vries
- Amsterdam UMC, Vrije Universiteit Amsterdam, Department of Molecular Cell Biology and Immunology, Amsterdam Neuroscience, The Netherlands
| |
Collapse
|
47
|
Impaired Cerebral Vasomotor Reactivity in Alzheimer's Disease. Int J Alzheimers Dis 2018; 2018:9328293. [PMID: 30271632 PMCID: PMC6151226 DOI: 10.1155/2018/9328293] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Revised: 06/30/2018] [Accepted: 07/26/2018] [Indexed: 12/30/2022] Open
Abstract
Background Recent studies have shown that cerebral vascularity may be impaired in Alzheimer's disease. Cerebral vasomotor reactivity could be an important biomarker for this pathology. Aims The aim of this study was to investigate the alterations in cerebral vascular motor reactivity in Alzheimer's disease subjects and to associate these changes with their cognitive scores. Methods We recruited subjects with a diagnosis of Alzheimer's disease and healthy controls. Demographic, clinical, imaging, and cognitive test were obtained. Then all participants performed a cerebral vascular motor reactivity test with 7% CO2 and cerebral blood flow velocities (CBFV) were recorded with transcranial doppler ultrasound before and after the test. Results We recruited 45 subjects, 26 (21 female) Alzheimer's disease participants and 19 (15 female) healthy controls. There were no differences in baseline cerebral blood flow velocities between the groups. After the cerebral vasomotor reactivity test, absolute mean difference in mean CBFV (ΔCBFV-m) was 8.70±4.14 versus 4.81±6.96 (p<0.01), respectively. Calculated percentage of change (%CVMR) was lower in the AD group 7.45±18.25 versus 23.29±17.48, and there was a positive but weak correlation with mini-mental scores (ρ=0.337, p=0.023). Conclusions In this study, Alzheimer's disease subjects showed significant changes in all absolute cerebral blood flow velocities after the cerebral vasomotor reactivity test with CO2, but only diastolic phase responses were statistically significant. There was a positive but weak correlation between cerebral vasomotor reactivity and cognitive scores. Further studies are needed to investigate these effects in larger Latin-American samples.
Collapse
|
48
|
Li G, He X, Li H, Wu Y, Guan Y, Liu S, Jia H, Li Y, Wang L, Huang R, Pei Z, Lan Y, Zhang Y. Overexpression of Slit2 improves function of the paravascular pathway in the aging mouse brain. Int J Mol Med 2018; 42:1935-1944. [PMID: 30085336 PMCID: PMC6108881 DOI: 10.3892/ijmm.2018.3802] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2017] [Accepted: 07/24/2018] [Indexed: 12/19/2022] Open
Abstract
Aging is associated with impairment of the paravascular pathway caused by the activation of astrocytes and depolarization of protein aquaporin-4 (AQP4) water channels, resulting in the accumulation of protein waste, including amyloid β (Aβ), in the brain parenchyma. The secreted glycoprotein slit guidance ligand 2 (Slit2) is important in regulating the function of the central nervous system and inflammatory response process. In the present study, 15-month-old Slit2 overexpression transgenic mice (Slit2-Tg mice) and two-photon fluorescence microscopy were used to evaluate the dynamic clearance of the paravascular pathway and the integrity of the blood-brain barrier (BBB). The reactivity of astrocytes, polarity of AQP4 and deposition of Aβ in the brain parenchyma were analyzed by immunofluorescence. A Morris water maze test was used to examine the effect of Slit2 on spatial memory cognition in aging mice. It was found that the overexpression of Slit2 improved the clearance of the paravascular pathway by inhibiting astrocyte activation and maintaining AQP4 polarity on the astrocytic endfeet in Slit2-Tg mice. In addition, Slit2 restored the disruption of the BBB caused by aging. The accumulation of Aβ was significantly reduced in the brain of Slit2-Tg mice. Furthermore, the water maze experiment showed that Slit2 improved spatial memory cognition in the aging mice. These results indicated that Slit2 may have the potential to be used in the prevention and treatment of neurodegenerative diseases in the elderly.
Collapse
Affiliation(s)
- Ge Li
- Guangdong Provincial Key Laboratory of Laboratory Animals, Guangdong Laboratory Animals Monitoring Institute, Guangzhou, Guangdong 510663, P.R. China
| | - Xiaofei He
- Department of Neurology, National Key Clinical Department and Key Discipline of Neurology, Guangdong Key Laboratory for Diagnosis and Treatment of Major Neurological Diseases, The First Affiliated Hospital, Sun Yat‑sen University, Guangzhou, Guangdong 510080, P.R. China
| | - Hang Li
- Guangdong Provincial Key Laboratory of Laboratory Animals, Guangdong Laboratory Animals Monitoring Institute, Guangzhou, Guangdong 510663, P.R. China
| | - Yu'e Wu
- Guangdong Provincial Key Laboratory of Laboratory Animals, Guangdong Laboratory Animals Monitoring Institute, Guangzhou, Guangdong 510663, P.R. China
| | - Yalun Guan
- Guangdong Provincial Key Laboratory of Laboratory Animals, Guangdong Laboratory Animals Monitoring Institute, Guangzhou, Guangdong 510663, P.R. China
| | - Shuhua Liu
- Guangdong Provincial Key Laboratory of Laboratory Animals, Guangdong Laboratory Animals Monitoring Institute, Guangzhou, Guangdong 510663, P.R. China
| | - Huanhuan Jia
- Guangdong Provincial Key Laboratory of Laboratory Animals, Guangdong Laboratory Animals Monitoring Institute, Guangzhou, Guangdong 510663, P.R. China
| | - Yunfeng Li
- Guangdong Provincial Key Laboratory of Laboratory Animals, Guangdong Laboratory Animals Monitoring Institute, Guangzhou, Guangdong 510663, P.R. China
| | - Lijing Wang
- Vascular Biology Research Institute, School of Basic Course, Guangdong Pharmaceutical University, Guangzhou, Guangdong 510006, P.R. China
| | - Ren Huang
- Guangdong Provincial Key Laboratory of Laboratory Animals, Guangdong Laboratory Animals Monitoring Institute, Guangzhou, Guangdong 510663, P.R. China
| | - Zhong Pei
- Department of Neurology, National Key Clinical Department and Key Discipline of Neurology, Guangdong Key Laboratory for Diagnosis and Treatment of Major Neurological Diseases, The First Affiliated Hospital, Sun Yat‑sen University, Guangzhou, Guangdong 510080, P.R. China
| | - Yue Lan
- Department of Rehabilitation Medicine, Guangzhou First People's Hospital, Guangzhou Medical University, Guangzhou, Guangdong 510180, P.R. China
| | - Yu Zhang
- Guangdong Provincial Key Laboratory of Laboratory Animals, Guangdong Laboratory Animals Monitoring Institute, Guangzhou, Guangdong 510663, P.R. China
| |
Collapse
|
49
|
Carlson BW, Craft MA, Carlson JR, Razaq W, Deardeuff KK, Benbrook DM. Accelerated vascular aging and persistent cognitive impairment in older female breast cancer survivors. GeroScience 2018; 40:325-336. [PMID: 29804200 DOI: 10.1007/s11357-018-0025-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Accepted: 05/15/2018] [Indexed: 12/18/2022] Open
Abstract
Advances in breast cancer treatment have markedly increased survivorship over the past three decades, with over 3.1 million survivors expected to live into their 70s and 80s. Without symptom relief interventions, nearly 35% of these survivors will have life-altering and distressing cognitive symptoms. This pilot study explored associations between serum markers of vascular aging, laterality in cerebral oxygenation, and severity of cognitive impairment in women, 12-18 months after chemotherapy for stage 2/3 invasive ductal breast cancer. Fifteen women (52-84 years) underwent a brief cognitive assessment (Montreal Cognitive Assessment [MOCA]) and blood draws to assess markers of vascular aging (interleukin-6 [IL-6], tumor necrosis factor alpha [TNF-α], C-reactive protein [CRP], and insulin growth factor-1 [IGF-1]). All underwent a computer-based test protocol that is known to increase blood flow within the frontal lobes. Percent cerebral oxyhemoglobin saturation (rcSO2) was recorded during and after testing. Laterality in rcSO2 was defined by ≥ 3% difference between left and right rcSO2 (|rcSO2 meanRIGHT - meanLEFT|). Eight participants had MOCA scores between 21 and 25 points, suggestive of mild cognitive impairment. Neither CRP (r = -.24) nor IL-6 (r = .34) nor TNF-α (r = .002) were associated with MOCA scores. Higher IL-6 was associated with greater laterality (r = .41). MOCA scores were significantly lower in subjects with laterality in rcSO2 than in those without laterality (F(1,14) = 13.5, p = 003). Lower IGF-1 was significantly associated with greater laterality (r = - .66, p = .007) and lower cognitive function (r = .58). These findings suggest that persistent cognitive impairment is associated with phenotypical changes consistent with accelerated vascular aging.
Collapse
Affiliation(s)
- Barbara W Carlson
- Fran and Earl Ziegler College of Nursing, University of Oklahoma Health Sciences Center, 1100 North Stonewall Avenue, Oklahoma City, OK, 73017, USA.
| | - Melissa A Craft
- Fran and Earl Ziegler College of Nursing, University of Oklahoma Health Sciences Center, 1100 North Stonewall Avenue, Oklahoma City, OK, 73017, USA
| | - John R Carlson
- Fran and Earl Ziegler College of Nursing, University of Oklahoma Health Sciences Center, 1100 North Stonewall Avenue, Oklahoma City, OK, 73017, USA
| | - Wajeeha Razaq
- Stephenson Cancer Center, 800 NE 10th Street, Oklahoma City, OK, 73104, USA
| | - Kelley K Deardeuff
- Fran and Earl Ziegler College of Nursing, University of Oklahoma Health Sciences Center, 1100 North Stonewall Avenue, Oklahoma City, OK, 73017, USA
| | - Doris M Benbrook
- Department of Obstetrics and Gynecology, Division of Gynecologic Oncology, University of Oklahoma Health Sciences Center (OUHSC), 975 NE 10th St, BRC 1217A, Oklahoma City, OK, 73104, USA
| |
Collapse
|
50
|
Boedtkjer E. Acid-base regulation and sensing: Accelerators and brakes in metabolic regulation of cerebrovascular tone. J Cereb Blood Flow Metab 2018; 38:588-602. [PMID: 28984162 PMCID: PMC5888856 DOI: 10.1177/0271678x17733868] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Revised: 08/10/2017] [Accepted: 09/06/2017] [Indexed: 12/29/2022]
Abstract
Metabolic regulation of cerebrovascular tone directs blood flow to areas of increased neuronal activity and during disease states partially compensates for insufficient perfusion by enhancing blood flow in collateral blood vessels. Acid-base disturbances frequently occur as result of enhanced metabolism or insufficient blood supply, but despite definitive evidence that acid-base disturbances alter arterial tone, effects of individual acid-base equivalents and the underlying signaling mechanisms are still being debated. H+ is an important intra- and extracellular messenger that modifies cerebrovascular tone. In addition, low extracellular [HCO3-] promotes cerebrovascular contraction through an endothelium-dependent mechanism. CO2 alters arterial tone development via changes in intra- and extracellular pH but it is still controversial whether CO2 also has direct vasomotor effects. Vasocontractile responses to low extracellular [HCO3-] and acute CO2-induced decreases in intracellular pH can counteract H+-mediated vasorelaxation during metabolic and respiratory acidosis, respectively, and may thereby reduce the risk of capillary damage and cerebral edema that could be consequences of unopposed vasodilation. In this review, the signaling mechanisms for acid-base equivalents in cerebral arteries and the mechanisms of intracellular pH control in the arterial wall are discussed in the context of metabolic regulation of cerebrovascular tone and local perfusion.
Collapse
Affiliation(s)
- Ebbe Boedtkjer
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| |
Collapse
|