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Obese mice exposed to psychosocial stress display cardiac and hippocampal dysfunction associated with local brain-derived neurotrophic factor depletion. EBioMedicine 2019; 47:384-401. [PMID: 31492565 PMCID: PMC6796537 DOI: 10.1016/j.ebiom.2019.08.042] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2019] [Revised: 08/13/2019] [Accepted: 08/20/2019] [Indexed: 01/14/2023] Open
Abstract
INTRODUCTION Obesity and psychosocial stress (PS) co-exist in individuals of Western society. Nevertheless, how PS impacts cardiac and hippocampal phenotype in obese subjects is still unknown. Nor is it clear whether changes in local brain-derived neurotrophic factor (BDNF) account, at least in part, for myocardial and behavioral abnormalities in obese experiencing PS. METHODS In adult male WT mice, obesity was induced via a high-fat diet (HFD). The resident-intruder paradigm was superimposed to trigger PS. In vivo left ventricular (LV) performance was evaluated by echocardiography and pressure-volume loops. Behaviour was indagated by elevated plus maze (EPM) and Y-maze. LV myocardium was assayed for apoptosis, fibrosis, vessel density and oxidative stress. Hippocampus was analyzed for volume, neurogenesis, GABAergic markers and astrogliosis. Cardiac and hippocampal BDNF and TrkB levels were measured by ELISA and WB. We investigated the pathogenetic role played by BDNF signaling in additional cardiac-selective TrkB (cTrkB) KO mice. FINDINGS When combined, obesity and PS jeopardized LV performance, causing prominent apoptosis, fibrosis, oxidative stress and remodeling of the larger coronary branches, along with lower BDNF and TrkB levels. HFD/PS weakened LV function similarly in WT and cTrkB KO mice. The latter exhibited elevated LV ROS emission already at baseline. Obesity/PS augmented anxiety-like behaviour and impaired spatial memory. These changes were coupled to reduced hippocampal volume, neurogenesis, local BDNF and TrkB content and augmented astrogliosis. INTERPRETATION PS and obesity synergistically deteriorate myocardial structure and function by depleting cardiac BDNF/TrkB content, leading to augmented oxidative stress. This comorbidity triggers behavioral deficits and induces hippocampal remodeling, potentially via lower BDNF and TrkB levels. FUND: J.A. was in part supported by Rotary Foundation Global Study Scholarship. G.K. was supported by T32 National Institute of Health (NIH) training grant under award number 1T32AG058527. S.C. was funded by American Heart Association Career Development Award (19CDA34760185). G.A.R.C. was funded by NIH (K01HL133368-01). APB was funded by a Grant from the Friuli Venezia Giulia Region entitled: "Heart failure as the Alzheimer disease of the heart; therapeutic and diagnostic opportunities". M.C. was supported by PRONAT project (CNR). N.P. was funded by NIH (R01 HL136918) and by the Magic-That-Matters fund (JHU). V.L. was in part supported by institutional funds from Scuola Superiore Sant'Anna (Pisa, Italy), by the TIM-Telecom Italia (WHITE Lab, Pisa, Italy), by a research grant from Pastificio Attilio Mastromauro Granoro s.r.l. (Corato, Italy) and in part by ETHERNA project (Prog. n. 161/16, Fondazione Pisa, Italy). Funding source had no such involvement in study design, in the collection, analysis, interpretation of data, in the writing of the report; and in the decision to submit the paper for publication.
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Prasad Hrishi A, Ruby Lionel K, Prathapadas U. Head Rules Over the Heart: Cardiac Manifestations of Cerebral Disorders. Indian J Crit Care Med 2019; 23:329-335. [PMID: 31406441 PMCID: PMC6686577 DOI: 10.5005/jp-journals-10071-23208] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The Brain-Heart interaction is becoming increasingly important as the underlying pathophysiological mechanisms become better understood. "Neurocardiology" is a new field which explores the pathophysiological interplay of the brain and cardiovascular systems. Brain-heart cross-talk presents as a result of direct stimulation of some areas of the brain, leading to a sympathetic or parasympathetic response or it may present as a result of a neuroendocrine response attributing to a clinical picture of a sympathetic storm. It manifests as cardiac rhythm disturbances, hemodynamic perturbations and in the worst scenarios as cardiac failure and death. Brain-Heart interaction (BHI) is most commonly encountered in traumatic brain injury and subarachnoid hemorrhage presenting as dramatic electrocardiographic changes, neurogenic stunned myocardium or even as ventricular fibrillation. A well-known example of BHI is the panic disorders and emotional stress resulting in Tako-tsubo syndrome giving rise to supraventricular and ventricular tachycardias and transient left ventricular dysfunction. In this review article, we will discuss cardiovascular changes caused due to the disorders of specific brain regions such as the insular cortex, brainstem, prefrontal cortex, hippocampus and the hypothalamus; neuro-cardiac reflexes namely the Cushing's reflex, the Trigemino-cardiac reflex and the Vagal reflex; and other pathological states such as neurogenic stunned myocardium /Takotsubo cardiomyopathy. There is a growing interest among intensivists and anesthesiologists in brain heart interactions as there are an increasing number of cases being reported and there is a need to address unanswered questions, such as the incidence of these interactions, the multifactorial pathogenesis, individual susceptibility, the role of medications, and optimal management. KEY MESSAGES BHI contribute in a significant way to the morbidity and mortality of neurological conditions such as traumatic brain injury, subarachnoid hemorrhage, cerebral infarction and status epilepticus. Constant vigilance and a high index of suspicion have to be exercised by clinicians to avoid misdiagnosis or delayed recognition. The entire clinical team involved in patient care should be aware of brain heart interaction to recognize these potentially life-threatening scenarios. HOW TO CITE THIS ARTICLE Hrishi AP, Lionel KR, Prathapadas U. Head Rules Over the Heart: Cardiac Manifestations of Cerebral Disorders. Indian J Crit Care Med 2019;23(7):329-335.
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Affiliation(s)
- Ajay Prasad Hrishi
- Division of Neuroanesthesia, Department of Anesthesiology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Thiruvananthapuram, Kerala, India
| | - Karen Ruby Lionel
- Department of Anesthesiology, Christian Medical College, Vellore, Tamil Nadu, India
| | - Unnikrishnan Prathapadas
- Division of Neuroanesthesia, Department of Anesthesiology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Thiruvananthapuram, Kerala, India
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Hosseini SM, Gholami Pourbadie H, Naderi N, Sayyah M, Zibaii MI. Photothrombotically induced unilateral selective hippocampal ischemia in rat. J Pharmacol Toxicol Methods 2018; 94:77-86. [DOI: 10.1016/j.vascn.2018.06.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Revised: 05/09/2018] [Accepted: 06/08/2018] [Indexed: 02/06/2023]
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Neurocardiology: Cardiovascular Changes and Specific Brain Region Infarcts. BIOMED RESEARCH INTERNATIONAL 2017; 2017:5646348. [PMID: 28758117 PMCID: PMC5512017 DOI: 10.1155/2017/5646348] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Accepted: 05/15/2017] [Indexed: 11/18/2022]
Abstract
There are complex and dynamic reflex control networks between the heart and the brain, including cardiac and intrathoracic ganglia, spinal cord, brainstem, and central nucleus. Recent literature based on animal model and clinical trials indicates a close link between cardiac function and nervous systems. It is noteworthy that the autonomic nervous-based therapeutics has shown great potential in the management of atrial fibrillation, ventricular arrhythmia, and myocardial remodeling. However, the potential mechanisms of postoperative brain injury and cardiovascular changes, particularly heart rate variability and the presence of arrhythmias, are not understood. In this chapter, we will describe mechanisms of brain damage undergoing cardiac surgery and focus on the interaction between cardiovascular changes and damage to specific brain regions.
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Evonuk KS, Prabhu SD, Young ME, DeSilva TM. Myocardial ischemia/reperfusion impairs neurogenesis and hippocampal-dependent learning and memory. Brain Behav Immun 2017; 61:266-273. [PMID: 27600185 PMCID: PMC5511033 DOI: 10.1016/j.bbi.2016.09.001] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Revised: 08/25/2016] [Accepted: 09/02/2016] [Indexed: 11/16/2022] Open
Abstract
The incidence of cognitive impairment in cardiovascular disease (CVD) patients has increased, adversely impacting quality of life and imposing a significant economic burden. Brain imaging of CVD patients has detected changes in the hippocampus, a brain region critical for normal learning and memory. However, it is not clear whether adverse cardiac events or other associated co-morbidities impair cognition. Here, using a murine model of acute myocardial ischemia/reperfusion (I/R), where the coronary artery was occluded for 30min followed by reperfusion, we tested the hypothesis that acute myocardial infarction triggers impairment in cognitive function. Two months following cardiac I/R, behavioral assessments specific for hippocampal cognitive function were performed. Mice subjected to cardiac I/R performed worse in the fear-conditioning paradigm as well as the object location memory behavioral test compared to sham-operated mice. Reactive gliosis was apparent in the hippocampal subregions CA1, CA3, and dentate gyrus 72h post-cardiac I/R as compared with sham, which was sustained two months post-cardiac I/R. Consistent with the inflammatory response, the abundance of doublecortin positive newborn neurons was decreased in the dentate gyrus 72h and 2months post-cardiac I/R as compared with sham. Therefore, we conclude that following acute myocardial infarction, rapid inflammatory responses negatively affect neurogenesis, which may underlie long-term changes in learning and memory.
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Affiliation(s)
- Kirsten S Evonuk
- Center for Glial Biology in Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, United States; Department of Physical Medicine Rehabilitation, University of Alabama at Birmingham, Birmingham, AL 35294, United States
| | - Sumanth D Prabhu
- Department of Medicine, Division of Cardiovascular Disease, University of Alabama at Birmingham, Birmingham, AL 35294, United States
| | - Martin E Young
- Department of Medicine, Division of Cardiovascular Disease, University of Alabama at Birmingham, Birmingham, AL 35294, United States
| | - Tara M DeSilva
- Center for Glial Biology in Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, United States; Department of Physical Medicine Rehabilitation, University of Alabama at Birmingham, Birmingham, AL 35294, United States; Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL 35294, United States.
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Pitkänen A, Roivainen R, Lukasiuk K. Development of epilepsy after ischaemic stroke. Lancet Neurol 2015; 15:185-197. [PMID: 26597090 DOI: 10.1016/s1474-4422(15)00248-3] [Citation(s) in RCA: 131] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2015] [Revised: 09/16/2015] [Accepted: 09/16/2015] [Indexed: 12/20/2022]
Abstract
For about 30% of patients with epilepsy the cause is unknown. Even in patients with a known risk factor for epilepsy, such as ischaemic stroke, only a subpopulation of patients develops epilepsy. Factors that contribute to the risk for epileptogenesis in a given individual generally remain unknown. Studies in the past decade on epilepsy in patients with ischaemic stroke suggest that, in addition to the primary ischaemic injury, existing difficult-to-detect microscale changes in blood vessels and white matter present as epileptogenic pathologies. Injury severity, location and type of pathological changes, genetic factors, and pre-injury and post-injury exposure to non-genetic factors (ie, the exposome) can divide patients with ischaemic stroke into different endophenotypes with a variable risk for epileptogenesis. These data provide guidance for animal modelling of post-stroke epilepsy, and for laboratory experiments to explore with increased specificity the molecular 'mechanisms, biomarkers, and treatment targets of post-stroke epilepsy in different circumstances, with the aim of modifying epileptogenesis after ischaemic stroke in individual patients without compromising recovery.
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Affiliation(s)
- Asla Pitkänen
- Department of Neurobiology, A. I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland.
| | - Reina Roivainen
- Department of Neurology, Hyvinkää Hospital, Hyvinkää, Finland
| | - Katarzyna Lukasiuk
- The Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, Poland
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Hui DS, Morley JE, Mikolajczak PC, Lee R. Atrial fibrillation: A major risk factor for cognitive decline. Am Heart J 2015; 169:448-56. [PMID: 25819850 DOI: 10.1016/j.ahj.2014.12.015] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/14/2014] [Accepted: 12/08/2014] [Indexed: 01/08/2023]
Abstract
Atrial fibrillation is a common disease of the elderly, conferring considerable morbidity and mortality related to cardiovascular effects and thromboembolic risks. Anticoagulation, antiarrhythmic medications, and rate control are the cornerstone of contemporary management, whereas ablation and evolving surgical techniques continue to play important secondary roles. Growing evidence shows that atrial fibrillation is also a risk factor for significant cognitive decline through a multitude of pathways, further contributing to morbidity and mortality. At the same time, cognitive decline associated with cryptogenic strokes may be the first clue to previously undiagnosed atrial fibrillation. These overlapping associations support the concept of cognitive screening and rhythm monitoring in these populations. New research suggests modulating effects of currently accepted treatments for atrial fibrillation on cognition; however, there remains the need for large multicenter studies to examine the effects of novel oral anticoagulants, rhythm and rate control, and left atrial appendage occlusion on long-term cognitive function.
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Affiliation(s)
- Dawn S Hui
- Center for Comprehensive Cardiovascular Care, Saint Louis University, St Louis, MO
| | - John E Morley
- Divisions of Geriatric Medicine and Endocrinology, Saint Louis University School of Medicine, St Louis, MO.
| | - Peter C Mikolajczak
- Center for Comprehensive Cardiovascular Care, Saint Louis University, St Louis, MO
| | - Richard Lee
- Center for Comprehensive Cardiovascular Care, Saint Louis University, St Louis, MO
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Woo MA, Ogren JA, Abouzeid CM, Macey PM, Sairafian KG, Saharan PS, Thompson PM, Fonarow GC, Hamilton MA, Harper RM, Kumar R. Regional hippocampal damage in heart failure. Eur J Heart Fail 2015; 17:494-500. [PMID: 25704495 DOI: 10.1002/ejhf.241] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2014] [Revised: 01/07/2015] [Accepted: 01/09/2015] [Indexed: 01/29/2023] Open
Abstract
AIMS Heart failure (HF) patients show cognitive and mood impairments, including short-term memory loss and depression, that have an adverse impacting on quality of life and self-care management. Brain regions, including the hippocampus, a structure significantly involved in memory and mood, show injury in HF, but the integrity of specific hippocampal subregions is unclear. METHODS AND RESULTS To assess regional hippocampal volume loss, we evaluated 17 HF patients (mean age ± SD, 54.4 ± 2.0 years; 12 male, left ventricular ejection fraction 28.3 ± 6.8%; New York Heart Association class II/III 94%/6%) and 34 healthy control subjects (52.3 ± 1.3 years; 24 male) using high-resolution T1-weighted magnetic resonance imaging and evaluated localized surface changes with morphometric procedures. Hippocampi were manually outlined, and volumes calculated from normalized tracings. Volume differences between groups were assessed by two-sample t-tests, and regional differences were assessed by surface morphometry. Patients with HF exhibited smaller hippocampal volumes than controls (right 3060 ± 146 mm(3) vs. 3478 ± 94 mm(3), P = 0.02; left 3021 ± 145 mm(3) vs. 3352 ± 98 mm(3), P = 0.06). Volume reductions were detected principally in CA1, an area integral to an array of learning and memory functions, as well as in mid to posterior CA3 and subiculum. CONCLUSION The hippocampus shows regional volume reduction in HF, which may contribute to short-term memory loss and depression associated with the condition.
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Affiliation(s)
- Mary A Woo
- UCLA School of Nursing, 700 Tiverton Avenue, Los Angeles, CA, 90095-1702, USA
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Abstract
Alzheimer's disease/senile dementia of the Alzheimer type (AD/SDAT) is the most common neuropathologic substrate of dementia. It is characterized by synapse loss (predominantly within neocortex) as well as deposition of certain distinctive lesions (the result of protein misfolding) throughout the brain. The latter include senile plaques, composed mainly of an amyloid (Aβ) core and a neuritic component; neurofibrillary tangles, composed predominantly of hyperphosphorylated tau; and cerebral amyloid angiopathy, a microangiopathy affecting both cerebral cortical capillaries and arterioles and resulting from Aβ deposition within their walls or (in the case of capillaries) immediately adjacent brain parenchyma. In this article, I discuss the hypothesized role these lesions play in causing cerebral dysfunction, as well as CSF and neuroimaging biomarkers (for dementia) that are especially relevant as immunotherapeutic approaches are being developed to remove Aβ from the brain parenchyma. In addition, I address the role of neuropathology in characterizing the sequelae of new AD/SDAT therapies and helping to validate CSF and neuroimaging biomarkers of disease. Comorbidity of AD/SDAT and various types of cerebrovascular disease is a major theme in dementia research, especially as cognitive impairment develops in the oldest old, who are especially vulnerable to ischemic and hemorrhagic brain lesions.
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Affiliation(s)
- Harry V Vinters
- Department of Pathology and Laboratory Medicine (Neuropathology), UCLA Medical Center, Los Angeles, California 90095-1732;
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Consensus Recommendations on Pathologic Changes in the Hippocampus: A Postmortem Multicenter Inter-Rater Study. J Neuropathol Exp Neurol 2013; 72:452-61. [DOI: 10.1097/nen.0b013e318292492a] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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Zheng Z, Zeng Y, Wu J. Increased neuroplasticity may protect against cardiovascular disease. Int J Neurosci 2013; 123:599-608. [PMID: 23510138 DOI: 10.3109/00207454.2013.785949] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Neuroplasticity refers to the capacity of the nervous system to modify its organization such that the brain can be shaped by environmental input. Individuals exhibit different degrees of neuroplasticity because of their different courses of growth. Neuroplasticity may thus play a role in individual differences in the treatment of neuropsychiatric diseases. The nervous system monitors and coordinates internal organ function. Thus neuroplasticity may also be associated with the pathogenesis and the treatment of some other diseases besides neuropsychiatric diseases. The cardiovascular system is controlled by the nervous system, mainly by the autonomic nervous system. Stress may lead to depression and cardiovascular disease (CVD). CVD is associated with depression, which is a disorder of decreased neuroplasticity. And the mechanisms of depression and CVD are related. So we conclude that decreased neuroplasticity causes the coexistence of depression with CVD, and increased neuroplasticity may be beneficial against the development of CVD. This theory provides another angle that can explain some of the reported phenomena related to CVD and neuropsychiatry and provide a potential treatment to protect against CVD.
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Affiliation(s)
- Zhihua Zheng
- Guangdong Province Pharmaceutical Association, Guangzhou, China.
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Kalaria RN. Cerebrovascular disease and mechanisms of cognitive impairment: evidence from clinicopathological studies in humans. Stroke 2012; 43:2526-34. [PMID: 22879100 DOI: 10.1161/strokeaha.112.655803] [Citation(s) in RCA: 151] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Raj N Kalaria
- Institute for Ageing and Health, Campus for Ageing & Vitality, Newcastle upon Tyne, NE4 5PL, UK.
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Deramecourt V, Slade JY, Oakley AE, Perry RH, Ince PG, Maurage CA, Kalaria RN. Staging and natural history of cerebrovascular pathology in dementia. Neurology 2012; 78:1043-50. [PMID: 22377814 DOI: 10.1212/wnl.0b013e31824e8e7f] [Citation(s) in RCA: 194] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
OBJECTIVE Most pathologic studies indicate that significant vascular changes are found in the majority of elderly persons, either alone or in association with neurodegenerative processes such as Alzheimer disease (AD) or dementia with Lewy bodies (DLB). Cumulative burden of cerebrovascular lesions can explain cognitive decline described as vascular cognitive impairment, but because there is a lack of consensus in the best way to quantify vascular pathology, the relationship between cognitive decline and cerebrovascular disease remains uncertain. We developed a rating scheme for cerebrovascular lesions using postmortem brains from patients with dementia from 2 European tertiary care memory clinics. METHODS A total of 135 brains with a neuropathologic diagnosis of vascular dementia (VaD) (n = 26), AD + VaD (n = 39), DLB + VaD (n = 21), AD + DLB + VaD (n = 9), AD (n = 19), and DLB (n = 21) were investigated in this study. Cerebrovascular lesions were rated on large sections from the hippocampus, the temporal lobe, the frontal lobe, and basal ganglia. RESULTS In patients with dementia, vessel wall modifications such as arteriolosclerosis or amyloid angiopathy are the most common and presumably the earliest changes. Modifications in perivascular spaces and myelin loss are the next most common. Lacunar or regional infarcts may occur as a consequence of an independent process or in the final phase of small vessel diseases. CONCLUSION A staging system based on this conceptual model of cerebrovascular pathology could enable the neuropathologic quantification of the cerebrovascular burden in dementia. Further studies are needed to determine whether this system can be used in large-scale studies to understand clinical-cerebrovascular pathologic correlations.
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Affiliation(s)
- V Deramecourt
- Institute for Ageing and Health, Campus for Ageing and Vitality, Newcastle University, Newcastle upon Tyne, UK
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Cherbuin N, Sachdev PS, Anstey KJ. Mixed handedness is associated with greater age-related decline in volumes of the hippocampus and amygdala: the PATH through life study. Brain Behav 2011; 1:125-34. [PMID: 22399092 PMCID: PMC3236539 DOI: 10.1002/brb3.24] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2011] [Accepted: 08/05/2011] [Indexed: 11/07/2022] Open
Abstract
Handedness has been found to be associated with structural and functional cerebral differences. Left handedness and mixed handedness also appear to be associated with an elevated risk of some developmental and immunological disorders that may contribute to pathological processes developing in ageing. Inconsistent reports show that left handedness may be more prevalent in early-onset as well as late-onset Alzheimer's disease, but might also be associated with slower decline. Such inconsistencies may be due to handedness being usually modeled as a binary construct while substantial evidence suggests it to be a continuous trait. The aim of this study was to investigate the relationship between brain structures known to be implicated in pathological ageing and strength and direction of handedness. The association between handedness and hippocampal and amygdalar atrophy was investigated in 327 cognitively healthy older individuals. Handedness was measured with the Edinburgh Inventory. Two measures were computed from this index, one reflecting the direction (left = 0/right = 1) and the other the degree of handedness (ranging from 0 to 1). Hippocampal and amygdalar volumes were manually traced on scans acquired 4 years apart. Regression analyses were used to assess the relationship between strength and direction of handedness and incident hippocampal and amygdalar atrophy. Analyses showed that strength but not direction of handedness was a significant predictor of hippocampal (Left: beta = 0.118, P = 0.013; Right: beta = 0.116, P = 0.010) and amygdalar (Right: beta = 0.105, P = 0.040) atrophy. The present findings suggest that mixed but not left handedness is associated with greater hippocampal and amygdalar atrophy. This effect may be due to genetic, environmental, or behavioural differences that will need further investigation in future studies.
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Affiliation(s)
- Nicolas Cherbuin
- Centre for Mental Health Research, Australian National UniversityCanberra, Australia
| | | | - Kaarin J Anstey
- Centre for Mental Health Research, Australian National UniversityCanberra, Australia
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