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Decourt B, D’Souza GX, Shi J, Ritter A, Suazo J, Sabbagh MN. The Cause of Alzheimer's Disease: The Theory of Multipathology Convergence to Chronic Neuronal Stress. Aging Dis 2022; 13:37-60. [PMID: 35111361 PMCID: PMC8782548 DOI: 10.14336/ad.2021.0529] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Accepted: 05/28/2021] [Indexed: 12/18/2022] Open
Abstract
The field of Alzheimer's disease (AD) research critically lacks an all-inclusive etiology theory that would integrate existing hypotheses and explain the heterogeneity of disease trajectory and pathologies observed in each individual patient. Here, we propose a novel comprehensive theory that we named: the multipathology convergence to chronic neuronal stress. Our new theory reconsiders long-standing dogmas advanced by previous incomplete theories. Firstly, while it is undeniable that amyloid beta (Aβ) is involved in AD, in the seminal stage of the disease Aβ is unlikely pathogenic. Instead, we hypothesize that the root cause of AD is neuronal stress in the central nervous system (CNS), and Aβ is expressed as part of the physiological response to protect CNS neurons from stress. If there is no return to homeostasis, then Aβ becomes overexpressed, and this includes the generation of longer forms that are more toxic and prone to oligomerization. Secondly, AD etiology is plausibly not strictly compartmentalized within the CNS but may also result from the dysfunction of other physiological systems in the entire body. This view implies that AD may not have a single cause, but rather needs to be considered as a spectrum of multiple chronic pathological modalities converging to the persistent stressing of CNS neurons. These chronic pathological modalities, which include cardiovascular disease, metabolic disorders, and CNS structural changes, often start individually, and over time combine with other chronic modalities to incrementally escalate the amount of stress applied to CNS neurons. We present the case for considering Aβ as a marker of neuronal stress in response to hypoxic, toxic, and starvation events, rather than solely a marker of AD. We also detail numerous human chronic conditions that can lead to neuronal stress in the CNS, making the link with co-morbidities encountered in daily clinical AD practice. Finally, we explain how our theory could be leveraged to improve clinical care for AD and related dementia in personalized medicine paradigms in the near future.
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Affiliation(s)
- Boris Decourt
- Translational Neurodegenerative Research Laboratory, Cleveland Clinic Lou Ruvo Center for Brain Health, Las Vegas, NV 89106, USA.
| | - Gary X D’Souza
- Department of Neurological Sciences, Rush University Medical Center, Chicago, IL, USA.
| | - Jiong Shi
- Translational Neurodegenerative Research Laboratory, Cleveland Clinic Lou Ruvo Center for Brain Health, Las Vegas, NV 89106, USA.
- Cleveland Clinic Nevada and Lou Ruvo Center for Brain Health, Las Vegas, NV 89106, USA.
| | - Aaron Ritter
- Cleveland Clinic Nevada and Lou Ruvo Center for Brain Health, Las Vegas, NV 89106, USA.
| | - Jasmin Suazo
- Translational Neurodegenerative Research Laboratory, Cleveland Clinic Lou Ruvo Center for Brain Health, Las Vegas, NV 89106, USA.
| | - Marwan N Sabbagh
- Translational Neurodegenerative Research Laboratory, Cleveland Clinic Lou Ruvo Center for Brain Health, Las Vegas, NV 89106, USA.
- Cleveland Clinic Nevada and Lou Ruvo Center for Brain Health, Las Vegas, NV 89106, USA.
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Karamanova N, Truran S, Serrano GE, Beach TG, Madine J, Weissig V, Davies HA, Veldhuizen J, Nikkhah M, Hansen M, Zhang W, D'Souza K, Franco DA, Migrino RQ. Endothelial Immune Activation by Medin: Potential Role in Cerebrovascular Disease and Reversal by Monosialoganglioside-Containing Nanoliposomes. J Am Heart Assoc 2020; 9:e014810. [PMID: 31928157 PMCID: PMC7033828 DOI: 10.1161/jaha.119.014810] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Background The function of medin, one of the most common human amyloid proteins that accumulates in the vasculature with aging, remains unknown. We aim to probe medin's role in cerebrovascular disease by comparing cerebral arterial medin content between cognitively normal and vascular dementia (VaD) patients and studying its effects on endothelial cell (EC) immune activation and neuroinflammation. We also tested whether monosialoganglioside‐containing nanoliposomes could reverse medin's adverse effects. Methods and Results Cerebral artery medin and astrocyte activation were measured and compared between VaD and cognitively normal elderly brain donors. ECs were exposed to physiologic dose of medin (5 μmol/L), and viability and immune activation (interleukin‐8, interleukin‐6, intercellular adhesion molecule‐1, and plasminogen activator inhibitor‐1) were measured without or with monosialoganglioside‐containing nanoliposomes (300 μg/mL). Astrocytes were exposed to vehicle, medin, medin‐treated ECs, or their conditioned media, and interleukin‐8 production was compared. Cerebral collateral arterial and parenchymal arteriole medin, white matter lesion scores, and astrocyte activation were higher in VaD versus cognitively normal donors. Medin induced EC immune activation (increased interleukin‐8, interleukin‐6, intercellular adhesion molecule‐1, and plasminogen activator inhibitor‐1) and reduced EC viability, which were reversed by monosialoganglioside‐containing nanoliposomes. Interleukin‐8 production was augmented when astrocytes were exposed to medin‐treated ECs or their conditioned media. Conclusions Cerebral arterial medin is higher in VaD compared with cognitively normal patients. Medin induces EC immune activation that modulates astrocyte activation, and its effects are reversed by monosialoganglioside‐containing nanoliposomes. Medin is a candidate novel risk factor for aging‐related cerebrovascular disease and VaD.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Mehdi Nikkhah
- Phoenix Veterans Affairs Phoenix AZ.,Arizona State University Tempe AZ
| | | | | | | | | | - Raymond Q Migrino
- Phoenix Veterans Affairs Phoenix AZ.,University of Arizona College of Medicine-Phoenix Phoenix AZ
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3
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Mikawa R, Okuno A, Yoshimi T, Watanabe A, Maruyama M, Takikawa O. Partial Identification of Amyloid-β Degrading Activity in Human Serum. NAGOYA JOURNAL OF MEDICAL SCIENCE 2019; 81:55-64. [PMID: 30962655 PMCID: PMC6433627 DOI: 10.18999/nagjms.81.1.55] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The major hallmarks of Alzheimer’s disease (AD) are the extracellular accumulation of pathological amyloid beta (Aβ) in the brain parenchyma and Aβ deposition in cerebral blood walls (cerebral amyloid angiopathy; CAA). Although CAA occurs in more than 80% of AD patients, the mechanisms of Aβ deposition and clearance around the vessel walls are unknown. We found Aβ-degrading activity in human serum during analysis of the regulatory mechanism of Aβ production in human endothelial cells. To elucidate the metabolic dynamics of Aβ surrounding the brain microvessels, we identified Aβ-degrading activity in human serum (blood Aβ-degrading activity: BADA) by column chromatography and LC/MS. BADA exhibited characteristics of an acidic protein, pI 4.3, which had two different protein surface charges (low and high affinity cations). Both BADA fractions had a relative molecular mass of greater than 400 kDa. Furthermore, BADA in the low affinity cation fraction was inhibited by the serine protease inhibitor 4-(2-Aminoethyl) benzenesulfonyl fluoride hydrochloride (AEBSF). We clarified alpha-2-macroglobulin (a2M) and several serine proteases from this BADA by LC-MS. Moreover, we demonstrated that BADA is increased by approximately 5000-fold in human serum by column chromatography. Therefore, BADA may play an important role in the circulation and metabolism of Aβ in human brain microvessels.
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Affiliation(s)
- Ryuta Mikawa
- Laboratory of Radiation Safety, Research Institute, National Center for Geriatrics and Gerontology, Obu, Japan.,Department of Aging Research, Program in Integrated Medicine, Graduate School of Medicine, Nagoya University, Nagoya, Japan
| | - Alato Okuno
- Laboratory of Radiation Safety, Research Institute, National Center for Geriatrics and Gerontology, Obu, Japan
| | - Tatsuya Yoshimi
- Laboratory of Radiation Safety, Research Institute, National Center for Geriatrics and Gerontology, Obu, Japan
| | - Atsushi Watanabe
- Laboratory of Research Advancement, Research Institute, National Center for Geriatrics and Gerontology, Obu, Japan
| | - Mitsuo Maruyama
- Department of Mechanism of Aging, Research Institute, National Center for Geriatrics and Gerontology, Obu, Japan.,Department of Aging Research, Program in Integrated Medicine, Graduate School of Medicine, Nagoya University, Nagoya, Japan
| | - Osamu Takikawa
- Laboratory of Radiation Safety, Research Institute, National Center for Geriatrics and Gerontology, Obu, Japan
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d'Uscio LV, He T, Katusic ZS. Expression and Processing of Amyloid Precursor Protein in Vascular Endothelium. Physiology (Bethesda) 2017; 32:20-32. [PMID: 27927802 DOI: 10.1152/physiol.00021.2016] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Amyloid precursor protein (APP) is evolutionary conserved protein expressed in endothelial cells of cerebral and peripheral arteries. In this review, we discuss mechanisms responsible for expression and proteolytic cleavage of APP in endothelial cells. We focus on physiological and pathological implications of APP expression in vascular endothelium.
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Affiliation(s)
- Livius V d'Uscio
- Departments of Anesthesiology and Molecular Pharmacology & Experimental Therapeutics, Mayo Clinic College of Medicine, Rochester, Minnesota
| | - Tongrong He
- Departments of Anesthesiology and Molecular Pharmacology & Experimental Therapeutics, Mayo Clinic College of Medicine, Rochester, Minnesota
| | - Zvonimir S Katusic
- Departments of Anesthesiology and Molecular Pharmacology & Experimental Therapeutics, Mayo Clinic College of Medicine, Rochester, Minnesota
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5
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Li JM, Huang LL, Liu F, Tang BS, Yan XX. Can brain impermeable BACE1 inhibitors serve as anti-CAA medicine? BMC Neurol 2017; 17:163. [PMID: 28841840 PMCID: PMC5574137 DOI: 10.1186/s12883-017-0942-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Accepted: 08/14/2017] [Indexed: 12/21/2022] Open
Abstract
Background Cerebral amyloid angiopathy (CAA) is characterized by the deposition of ß-amyloid peptides (Aß) in and surrounding the wall of microvasculature in the central nervous system, together with parenchymal amyloid plaques collectively referred to as cerebral amyloidosis, which occurs in the brain commonly among the elderly and more frequently in patients with Alzheimer’s disease (AD). CAA is associated with vascular injury and may cause devastating neurological outcomes. No therapeutic approach is available for this lesion to date. Main body ß-Secretase 1 (BACE1) is the enzyme initiating Aß production. Brain permeable BACE1 inhibitors targeting primarily at the parenchymal plaque pathology are currently evaluated in clinical trials. This article presents findings in support of a role of BACE1 elevation in the development of CAA, in addition to plaque pathogenesis. The rationale, feasibility, benefit and strategic issues for developing BACE1 inhibitors against CAA are discussed. Brain impermeable compounds are considered preferable as they might exhibit sufficient anti-CAA efficacy without causing significant neuronal/synaptic side effects. Conclusion Early pharmacological intervention to the pathogenesis of CAA is expected to provide significant protection for cerebral vascular health and hence brain health. Brain impermeable BACE1 inhibitors should be optimized and tested as potential anti-CAA therapeutics.
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Affiliation(s)
- Jian-Ming Li
- Department of Neurology & Key Laboratory of Hunan Province in Neurodegenerative Disorders, Xiangya Hospital, Central South University, Changsha, Hunan, 410008, China.,Neuroscience Research Center, Changsha Medical University, Changsha, Hunan, 410219, China
| | - Li-Ling Huang
- Department of Anatomy and Neurobiology, Central South University School of Basic Medical Science, Changsha, Hunan, 410013, China
| | - Fei Liu
- Department of Neurosurgery, The Third Xiangya Hospital, Central South University, Changsha, Hunan, 410013, China
| | - Bei-Sha Tang
- Department of Neurology & Key Laboratory of Hunan Province in Neurodegenerative Disorders, Xiangya Hospital, Central South University, Changsha, Hunan, 410008, China
| | - Xiao-Xin Yan
- Department of Neurology & Key Laboratory of Hunan Province in Neurodegenerative Disorders, Xiangya Hospital, Central South University, Changsha, Hunan, 410008, China. .,Department of Anatomy and Neurobiology, Central South University School of Basic Medical Science, Changsha, Hunan, 410013, China.
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Brenner SR. Alzheimer's disease and other neurodegenerative diseases may be due to nutritional deficiencies secondary to unrecognized exocrine pancreatic insufficiency. Med Hypotheses 2017; 102:89-90. [DOI: 10.1016/j.mehy.2017.03.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Accepted: 03/11/2017] [Indexed: 10/20/2022]
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7
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Deng X, Zhang J, Liu Y, Chen L, Yu C. TNF-α regulates the proteolytic degradation of ST6Gal-1 and endothelial cell-cell junctions through upregulating expression of BACE1. Sci Rep 2017; 7:40256. [PMID: 28091531 PMCID: PMC5238365 DOI: 10.1038/srep40256] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Accepted: 12/02/2016] [Indexed: 11/11/2022] Open
Abstract
Endothelial dysfunction and monocyte adhesion to vascular endothelial cells are two critical steps in atherosclerosis development, and emerging evidence suggests that protein sialylation is involved in these processes. However, the mechanism underlying this phenomenon remains incompletely elucidated. In this study, we demonstrated that treatment with the proinflammatory cytokine TNF-α disrupted vascular endothelial cell-cell tight junctions and promoted monocyte endothelial cell adhesion. Western blotting and Sambucus nigra lectin (SNA) blotting analyses revealed that TNF-α treatment decreased α-2, 6-sialic acid transferase 1 (ST6Gal-I) levels and downregulated VE-Cadherin α-2, 6 sialylation. Further analysis demonstrated that TNF-α treatment upregulated β-site amyloid precursor protein enzyme 1 (BACE1) expression, thus resulting in sequential ST6Gal-I proteolytic degradation. Furthermore, our results revealed that PKC signaling cascades were involved in TNF-α-induced BACE1 upregulation. Together, these results indicated that the proinflammatory cytokine TNF-α impairs endothelial tight junctions and promotes monocyte-endothelial cell adhesion by upregulating BACE1 expression through activating PKC signaling and sequentially cleaving ST6Gal-I. Thus, inhibition of BACE1 expression may be a new approach for treating atherosclerosis.
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Affiliation(s)
- Xiao Deng
- Institute of Life Science, Chongqing Medical University, Chongqing 400016, P. R. China
| | - Jun Zhang
- Institute of Life Science, Chongqing Medical University, Chongqing 400016, P. R. China
| | - Yan Liu
- Institute of Life Science, Chongqing Medical University, Chongqing 400016, P. R. China
| | - Linmu Chen
- Institute of Life Science, Chongqing Medical University, Chongqing 400016, P. R. China
| | - Chao Yu
- Institute of Life Science, Chongqing Medical University, Chongqing 400016, P. R. China
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Wang D, Lin Q, Su S, Liu K, Wu Y, Hai J. URB597 improves cognitive impairment induced by chronic cerebral hypoperfusion by inhibiting mTOR-dependent autophagy. Neuroscience 2016; 344:293-304. [PMID: 28042028 DOI: 10.1016/j.neuroscience.2016.12.034] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2016] [Revised: 12/16/2016] [Accepted: 12/21/2016] [Indexed: 12/19/2022]
Abstract
Chronic cerebral hypoperfusion (CCH) is associated with various ischemic cerebrovascular diseases that are characterized by cognitive impairment. The role of autophagy in cognitive dysfunction under conditions of CCH is poorly understood. To address this issue, the present study investigated the effect of the fatty acid amide hydrolase (FAAH) inhibitor URB597 on autophagy and cognition in a CCH model as well as the underlying mechanisms. Cognitive function was evaluated with the Morris water maze and by assessing long-term potentiation (LTP). The expression of autophagy-related proteins and mammalian target of rapamycin (mTOR) signaling pathway components was evaluated by immunofluorescence and western blot analyses, and ultrastructural changes were examined by transmission electron microscopy (EM). URB597 improved cognitive impairment by inhibiting CCH-induced autophagy, which was associated with mTOR signaling. Moreover, the ultrastructural deterioration resulting from CCH was improved by chronic treatment with URB597. These findings indicate that URB597 modulates autophagy in an mTOR-dependent manner, and mitigates neuronal damage and cognitive deterioration caused by CCH.
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Affiliation(s)
- Dapeng Wang
- Department of Neurosurgery, Tong Ji Hospital, Tong Ji University School of Medicine, Shanghai 200065, China
| | - Qi Lin
- Department of Pharmacy, Institutes of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Shaohua Su
- Department of Neurosurgery, Tong Ji Hospital, Tong Ji University School of Medicine, Shanghai 200065, China
| | - Kejia Liu
- Department of Cell Biology, Key Laboratory of Education Ministry for Cell Differentiation and Apoptosis, Institutes of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Yifang Wu
- Department of Neurosurgery, Tong Ji Hospital, Tong Ji University School of Medicine, Shanghai 200065, China
| | - Jian Hai
- Department of Neurosurgery, Tong Ji Hospital, Tong Ji University School of Medicine, Shanghai 200065, China.
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9
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Xue ZQ, He ZW, Yu JJ, Cai Y, Qiu WY, Pan A, Gai WP, Cai H, Luo XG, Ma C, Yan XX. Non-neuronal and neuronal BACE1 elevation in association with angiopathic and leptomeningeal β-amyloid deposition in the human brain. BMC Neurol 2015; 15:71. [PMID: 25934480 PMCID: PMC4428107 DOI: 10.1186/s12883-015-0327-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2014] [Accepted: 04/21/2015] [Indexed: 12/14/2022] Open
Abstract
Background Cerebral amyloid angiopathy (CAA) refers to the deposition of β-amyloid (Aβ) peptides in the wall of brain vasculature, commonly involving capillaries and arterioles. Also being considered a part of CAA is the Aβ deposition in leptomeninge. The cellular origin of angiopathic Aβ and the pathogenic course of CAA remain incompletely understood. Methods The present study was aimed to explore the pathogenic course of CAA in the human cerebrum via examination of changes in β-secretase-1 (BACE1), the obligatory Aβ producing enzyme, relative to Aβ and other cellular markers, by neuroanatomical and biochemical characterizations with postmortem brain samples and primary cell cultures. Results Immunoreactivity (IR) for BACE1 was essentially not visible at vasculature in cases without cerebral amyloidosis (control group, n = 15, age = 86.1 ± 10.3 year). In cases with brain amyloid pathology (n = 15, age = 78.7 ± 12.7 year), increased BACE1 IR was identified locally at capillaries, arterioles and along the pia, localizing to endothelia, perivascular dystrophic neurites and meningeal cells, and often coexisting with vascular iron deposition. Double immunofluorescence with densitometric analysis confirmed a site-specific BACE1 elevation at cerebral arterioles in the development of vascular Aβ deposition. Levels of BACE1 protein, activity and its immediate product (C99) were elevated in leptomeningeal lysates from cases with CAA relative to controls. The expression of BACE1 and other amyloidogenic proteins in the endothelial and meningeal cells was confirmed in primary cultures prepared from human leptomeningeal and arteriolar biopsies. Conclusion These results suggest that BACE1 elevation in the endothelia and perivascular neurites may be involved in angiopathic Aβ deposition, while BACE1 elevation in meningeal cells might contribute Aβ to leptomeningeal amyloidosis.
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Affiliation(s)
- Zhi-Qin Xue
- Department of Anatomy and Neurobiology, Central South University School of Basic Medical Science, Changsha, Hunan, 410013, China. .,Department of Anatomy, Xinjiang Medical University, Urumqi, Xinjiang, 830011, China.
| | - Zheng-Wen He
- Central South University Affiliated Tumor Hospital, Changsha, Hunan, 410006, China.
| | - Jian-Jun Yu
- Central South University Affiliated Tumor Hospital, Changsha, Hunan, 410006, China.
| | - Yan Cai
- Department of Anatomy and Neurobiology, Central South University School of Basic Medical Science, Changsha, Hunan, 410013, China.
| | - Wen-Ying Qiu
- Department of Human Anatomy, Histology and Embryology, Institute of Basic Medical Sciences, Neuroscience Center, Chinese Academy of Medical Sciences, School of Basic Medicine, Peking Union Medical College, Beijing, 100730, China.
| | - Aihua Pan
- Department of Anatomy and Neurobiology, Central South University School of Basic Medical Science, Changsha, Hunan, 410013, China.
| | - Wei-Ping Gai
- Department of Surgery and Centre for Neuroscience, Flinders University School of Medicine, Bedford Park, SA, 5042, Australia.
| | - Huaibin Cai
- Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bethesda, MD, 20892, USA.
| | - Xue-Gang Luo
- Department of Anatomy and Neurobiology, Central South University School of Basic Medical Science, Changsha, Hunan, 410013, China.
| | - Chao Ma
- Department of Human Anatomy, Histology and Embryology, Institute of Basic Medical Sciences, Neuroscience Center, Chinese Academy of Medical Sciences, School of Basic Medicine, Peking Union Medical College, Beijing, 100730, China.
| | - Xiao-Xin Yan
- Department of Anatomy and Neurobiology, Central South University School of Basic Medical Science, Changsha, Hunan, 410013, China.
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Mocali A, Della Malva N, Abete C, Mitidieri Costanza VA, Bavazzano A, Boddi V, Sanchez L, Dessì S, Pani A, Paoletti F. Altered proteolysis in fibroblasts of Alzheimer patients with predictive implications for subjects at risk of disease. Int J Alzheimers Dis 2014; 2014:520152. [PMID: 24949214 PMCID: PMC4052202 DOI: 10.1155/2014/520152] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2014] [Revised: 04/09/2014] [Accepted: 05/04/2014] [Indexed: 02/04/2023] Open
Abstract
There is great interest in developing reliable biomarkers to support antemortem diagnosis of late-onset Alzheimer's disease (AD). Early prediction and diagnosis of AD might be improved by the detection of a proteolytic dysfunction in extracts from cultured AD fibroblasts, producing altered isoelectrophoretic forms of the enzyme transketolase (TK-alkaline bands). The TK profile and apolipoprotein E (APOE) genotype were examined in fibroblasts from 36 clinically diagnosed probable late-onset sporadic AD patients and 38 of their asymptomatic relatives, 29 elderly healthy individuals, 12 neurological non-AD patients, and 5 early-onset AD patients. TK alterations occurred in (i) several probable AD patients regardless of age-of-onset and severity of disease; (ii) all early-onset AD patients and APOE ε 4/4 carriers; and (iii) nearly half of asymptomatic AD relatives. Normal subjects and non-AD patients were all negative. Notably, culture conditions promoting TK alterations were also effective in increasing active BACE1 levels. Overall, the TK assay might represent a low-cost laboratory tool useful for supporting AD differential diagnosis and identifying asymptomatic subjects who are at greater risk of AD and who should enter a follow-up study. Moreover, the cultured fibroblasts were confirmed as a useful in vitro model for further studies on the pathogenetic process of AD.
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Affiliation(s)
- Alessandra Mocali
- Section of Experimental Pathology and Oncology, Department of Biomedical Experimental and Clinical Sciences, University of Florence, 50134 Florence, Italy
| | - Nunzia Della Malva
- Section of Experimental Pathology and Oncology, Department of Biomedical Experimental and Clinical Sciences, University of Florence, 50134 Florence, Italy
| | - Claudia Abete
- Department of Internal Medicine, University of Cagliari, 09042 Monserrato, Italy
| | | | | | - Vieri Boddi
- Department of Public Health, University of Florence, 50134 Florence, Italy
| | - Luis Sanchez
- 1st Unit of General Surgery and Transplantation, Careggi Hospital, 50134 Florence, Italy
| | - Sandra Dessì
- Department of Internal Medicine, University of Cagliari, 09042 Monserrato, Italy
| | - Alessandra Pani
- Department of Biomedical Sciences, University of Cagliari, 09042 Monserrato, Italy
| | - Francesco Paoletti
- Section of Experimental Pathology and Oncology, Department of Biomedical Experimental and Clinical Sciences, University of Florence, 50134 Florence, Italy
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Wainaina MN, Chen Z, Zhong C. Environmental factors in the development and progression of late-onset Alzheimer's disease. Neurosci Bull 2014; 30:253-70. [PMID: 24664867 PMCID: PMC5562669 DOI: 10.1007/s12264-013-1425-9] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2013] [Accepted: 01/23/2014] [Indexed: 01/08/2023] Open
Abstract
Late-onset Alzheimer's disease (LOAD) is an age-related neurodegenerative disorder characterized by gradual loss of synapses and neurons, but its pathogenesis remains to be clarified. Neurons live in an environment constituted by neurons themselves and glial cells. In this review, we propose that the neuronal degeneration in the AD brain is partially caused by diverse environmental factors. We first discuss various environmental stresses and the corresponding responses at different levels. Then we propose some mechanisms underlying the specific pathological changes, in particular, hypothalamic-pituitary adrenal axis dysfunction at the systemic level; cerebrovascular dysfunction, metal toxicity, glial activation, and Aβ toxicity at the intercellular level; and kinase-phosphatase imbalance and epigenetic modification at the intracellular level. Finally, we discuss the possibility of developing new strategies for the prevention and treatment of LOAD from the perspective of environmental stress. We conclude that environmental factors play a significant role in the development of LOAD through multiple pathological mechanisms.
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Affiliation(s)
- Moses N. Wainaina
- Department of Neurology, Zhongshan Hospital; State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, 200032 China
- Pwani University, Kilifi, Kenya
| | - Zhichun Chen
- Department of Neurology, Zhongshan Hospital; State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, 200032 China
| | - Chunjiu Zhong
- Department of Neurology, Zhongshan Hospital; State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, 200032 China
- Institutes of Brain Science, Fudan University, Shanghai, 200032 China
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