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Li Z, Jiang YY, Long C, Peng X, Tao J, Pu Y, Yue R. Bridging metabolic syndrome and cognitive dysfunction: role of astrocytes. Front Endocrinol (Lausanne) 2024; 15:1393253. [PMID: 38800473 PMCID: PMC11116704 DOI: 10.3389/fendo.2024.1393253] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2024] [Accepted: 04/25/2024] [Indexed: 05/29/2024] Open
Abstract
Metabolic syndrome (MetS) and cognitive dysfunction pose significant challenges to global health and the economy. Systemic inflammation, endocrine disruption, and autoregulatory impairment drive neurodegeneration and microcirculatory damage in MetS. Due to their unique anatomy and function, astrocytes sense and integrate multiple metabolic signals, including peripheral endocrine hormones and nutrients. Astrocytes and synapses engage in a complex dialogue of energetic and immunological interactions. Astrocytes act as a bridge between MetS and cognitive dysfunction, undergoing diverse activation in response to metabolic dysfunction. This article summarizes the alterations in astrocyte phenotypic characteristics across multiple pathological factors in MetS. It also discusses the clinical value of astrocytes as a critical pathologic diagnostic marker and potential therapeutic target for MetS-associated cognitive dysfunction.
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Affiliation(s)
- Zihan Li
- Department of Endocrinology, Hospital of Chengdu University of Traditional Chinese Medicine, Chengdu, China
- Clinical Medical School, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Ya-yi Jiang
- Department of Endocrinology, Hospital of Chengdu University of Traditional Chinese Medicine, Chengdu, China
- Clinical Medical School, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Caiyi Long
- Department of Endocrinology, Hospital of Chengdu University of Traditional Chinese Medicine, Chengdu, China
- Clinical Medical School, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Xi Peng
- Department of Endocrinology, Hospital of Chengdu University of Traditional Chinese Medicine, Chengdu, China
- Clinical Medical School, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Jiajing Tao
- Department of Endocrinology, Hospital of Chengdu University of Traditional Chinese Medicine, Chengdu, China
- Clinical Medical School, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Yueheng Pu
- Department of Endocrinology, Hospital of Chengdu University of Traditional Chinese Medicine, Chengdu, China
- Clinical Medical School, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Rensong Yue
- Department of Endocrinology, Hospital of Chengdu University of Traditional Chinese Medicine, Chengdu, China
- Clinical Medical School, Chengdu University of Traditional Chinese Medicine, Chengdu, China
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Baggeroer CE, Cambronero FE, Savan NA, Jefferson AL, Santisteban MM. Basic Mechanisms of Brain Injury and Cognitive Decline in Hypertension. Hypertension 2024; 81:34-44. [PMID: 37732479 PMCID: PMC10840624 DOI: 10.1161/hypertensionaha.123.19939] [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] [Indexed: 09/22/2023]
Abstract
Dementia affects almost 50 million adults worldwide, and remains a major cause of death and disability. Hypertension is a leading risk factor for dementia, including Alzheimer disease and Alzheimer disease-related dementias. Although this association is well-established, the mechanisms underlying hypertension-induced cognitive decline remain poorly understood. By exploring the mechanisms mediating the detrimental effects of hypertension on the brain, studies have aimed to provide therapeutic insights and strategies on how to protect the brain from the effects of blood pressure elevation. In this review, we focus on the basic mechanisms contributing to the cerebrovascular adaptions to elevated blood pressure and hypertension-induced microvascular injury. We also assess the cellular mechanisms of neurovascular unit dysfunction, focusing on the premise that cognitive impairment ensues when the dynamic metabolic demands of neurons are not met due to neurovascular uncoupling, and summarize cognitive deficits across various rodent models of hypertension as a resource for investigators. Despite significant advances in antihypertensive therapy, hypertension remains a critical risk factor for cognitive decline, and several questions remain about the development and progression of hypertension-induced cognitive impairment.
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Affiliation(s)
- Caroline E. Baggeroer
- Vanderbilt Memory and Alzheimer’s Center, Vanderbilt University Medical Center, Nashville, TN
| | - Francis E. Cambronero
- Vanderbilt Memory and Alzheimer’s Center, Vanderbilt University Medical Center, Nashville, TN
| | - N. Anna Savan
- Medical Scientist Training Program, Yale University, New Haven, CT
| | - Angela L. Jefferson
- Vanderbilt Memory and Alzheimer’s Center, Vanderbilt University Medical Center, Nashville, TN
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN
| | - Monica M. Santisteban
- Vanderbilt Memory and Alzheimer’s Center, Vanderbilt University Medical Center, Nashville, TN
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN
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Lai AY, Bazzigaluppi P, Morrone CD, Hill ME, Stefanovic B, McLaurin J. Compromised Cortical-Hippocampal Network Function From Transient Hypertension: Linking Mid-Life Hypertension to Late Life Dementia Risk. Front Neurosci 2022; 16:897206. [PMID: 35812238 PMCID: PMC9260147 DOI: 10.3389/fnins.2022.897206] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Accepted: 06/06/2022] [Indexed: 11/20/2022] Open
Abstract
Mid-life hypertension is a major risk factor for developing dementia later in life. While anti-hypertensive drugs restore normotension, dementia risk remains above baseline suggesting that brain damage sustained during transient hypertension is irreversible. The current study characterized a rat model of transient hypertension with an extended period of normotensive recovery: F344 rats were treated with L-NG-Nitroarginine methyl ester (L-NAME) for 1 month to induce hypertension then allowed up to 4 months of recovery. With respect to cognitive deficits, comparison between 1 month and 4 months of recovery identified initial deficits in spatial memory that resolved by 4 months post-hypertension; contrastingly, loss of cognitive flexibility did not. The specific cells and brain regions underlying these cognitive deficits were investigated. Irreversible structural damage to the brain was observed in both the prefrontal cortex and the hippocampus, with decreased blood vessel density, myelin and neuronal loss. We then measured theta-gamma phase amplitude coupling as a readout for network function, a potential link between the observed cognitive and pathological deficits. Four months after hypertension, we detected decreased theta-gamma phase amplitude coupling within each brain region and a concurrent increase in baseline connectivity between the two regions reflecting an attempt to maintain function that may account for the improvement in spatial memory. Our results demonstrate that connectivity between prefrontal cortex and hippocampus is a vulnerable network affected by transient hypertension which is not rescued over time; thus demonstrating for the first time a mechanistic link between the long-term effects of transient hypertension and dementia risk.
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Affiliation(s)
- Aaron Y. Lai
- Biological Sciences, Sunnybrook Research Institute, Toronto, ON, Canada
- *Correspondence: Aaron Y. Lai,
| | - Paolo Bazzigaluppi
- Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada
| | | | - Mary E. Hill
- Biological Sciences, Sunnybrook Research Institute, Toronto, ON, Canada
| | - Bojana Stefanovic
- Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada
- Physical Sciences, Sunnybrook Research Institute, Toronto, ON, Canada
| | - JoAnne McLaurin
- Biological Sciences, Sunnybrook Research Institute, Toronto, ON, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada
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MacKenzie JL, Ivanova N, Nell HJ, Giordano CR, Terlecky SR, Agca C, Agca Y, Walton PA, Whitehead SN, Cechetto DF. Microglial inflammation and cognitive dysfunction in comorbid rat models of striatal ischemic stroke and alzheimer’s disease: effects of antioxidant catalase-SKL on behavioral and cellular pathology. Neuroscience 2022; 487:47-65. [DOI: 10.1016/j.neuroscience.2022.01.026] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 01/26/2022] [Accepted: 01/28/2022] [Indexed: 12/25/2022]
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Abstract
PURPOSE OF REVIEW The relationship between hypertension and Alzheimer's disease (AD) is complex and varies across the lifespan. Studies have suggested that midlife hypertension is a risk factor for AD, although studies of late life hypertension have suggested that it either has no effect or a weak protective effect. RECENT FINDINGS Animal models of induced and spontaneous hypertension have found that AD pathological change (β-amyloid plaques and tau tangles) occurs within weeks of a hypertensive insult. Human imaging and autopsy studies indicate that midlife and late life hypertension are associated with increased AD pathological change. Meta-analyses of longitudinal studies indicate that midlife rather than late life hypertension is a risk factor for AD. New areas of research have suggested that rather than mean blood pressure (BP), it is the negative BP trajectories or the variability of BP that contributes to AD. In a number of meta-analyses of antihypertensive medications and their effect on AD, there were weak associations between improved AD outcomes and treatment. SUMMARY The combined analysis of animal, human clinical/pathological, epidemiological and drug trial data indicates that hypertension increases the risk of AD and treatment of hypertension may be an appropriate preventive measure.
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