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Gard A, Kornaropoulos EN, Portonova Wernersson M, Rorsman I, Blennow K, Zetterberg H, Tegner Y, De Maio A, Markenroth Bloch K, Björkman-Burtscher I, Pessah-Rasmussen H, Nilsson M, Marklund N. Widespread White Matter Abnormalities in Concussed Athletes Detected by 7T Diffusion Magnetic Resonance Imaging. J Neurotrauma 2024; 41:1533-1549. [PMID: 38481124 DOI: 10.1089/neu.2023.0099] [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] [Indexed: 05/04/2024] Open
Abstract
Sports-related concussions may cause white matter injuries and persistent post-concussive symptoms (PPCS). We hypothesized that athletes with PPCS would have neurocognitive impairments and white matter abnormalities that could be revealed by advanced neuroimaging using ultra-high field strength diffusion tensor (DTI) and diffusion kurtosis (DKI) imaging metrics and cerebrospinal fluid (CSF) biomarkers. A cohort of athletes with PPCS severity limiting the ability to work/study and participate in sport school and/or social activities for ≥6 months completed 7T magnetic resonance imaging (MRI) (morphological T1-weighed volumetry, DTI and DKI), extensive neuropsychological testing, symptom rating, and CSF biomarker sampling. Twenty-two athletes with PPCS and 22 controls were included. Concussed athletes performed below norms and significantly lower than controls on all but one of the psychometric neuropsychology tests. Supratentorial white and gray matter, as well as hippocampal volumes did not differ between concussed athletes and controls. However, of the 72 examined white matter tracts, 16% of DTI and 35% of DKI metrics (in total 28%) were significantly different between concussed athletes and controls. DKI fractional anisotropy and axial kurtosis were increased, and DKI radial diffusivity and radial kurtosis decreased in concussed athletes when compared with controls. CSF neurofilament light (NfL; an axonal injury marker), although not glial fibrillary acidic protein, correlated with several diffusion metrics. In this first 7T DTI and DKI study investigating PPCS, widespread microstructural alterations were observed in the white matter, correlating with CSF markers of axonal injury. More white matter changes were observed using DKI than using DTI. These white matter alterations may indicate persistent pathophysiological processes following concussion in sport.
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Affiliation(s)
- Anna Gard
- Department of Clinical Sciences Lund, Neurosurgery, Neurology, Lund University, Lund, Sweden
| | - Evgenios N Kornaropoulos
- Department of Clinical Sciences Lund, Diagnostic Radiology, Neurology, Lund University, Lund, Sweden
| | - Maria Portonova Wernersson
- Department of Neurology, Rehabilitation Medicine, Memory Disorders and Geriatrics, Skåne University Hospital, Neurology, Lund University, Lund, Sweden
| | - Ia Rorsman
- Department of Clinical Sciences Lund, Neurology, Lund University, Lund, Sweden
| | - Kaj Blennow
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, Sahlgrenska University Hospital, Mölndal, Sweden
| | - Henrik Zetterberg
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, Sahlgrenska University Hospital, Mölndal, Sweden
- Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London, UK
- UK Dementia Research Institute at UCL, London, UK
- Hong Kong Center for Neurodegenerative Diseases, Clear Water Bay, Hong Kong, China
| | - Yelverton Tegner
- Department of Health, Education and Technology, Division of Health and Rehabilitation, Luleå University of Technology, Luleå, Sweden
| | - Alessandro De Maio
- Department of Radiological, Oncological and Pathological Sciences. Policlinico Umberto I, Sapienza University of Rome, Rome, Italy
| | - Karin Markenroth Bloch
- Department of Clinical Sciences Lund, Lund University Bioimaging Center, Lund University, Lund, Sweden
| | - Isabella Björkman-Burtscher
- Department of Radiology, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg and Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Hélène Pessah-Rasmussen
- Department of Neurology, Rehabilitation Medicine, Memory Disorders and Geriatrics, Skåne University Hospital, Neurology, Lund University, Lund, Sweden
- Department of Clinical Sciences Lund, Neurology, Lund University, Lund, Sweden
| | - Markus Nilsson
- Department of Clinical Sciences Lund, Diagnostic Radiology, Neurology, Lund University, Lund, Sweden
| | - Niklas Marklund
- Department of Clinical Sciences Lund, Neurosurgery, Lund University, and Skåne University Hospital, Lund, Sweden
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2
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Chen Q, Wu M, Tang Q, Yan P, Zhu L. Age-Related Alterations in Immune Function and Inflammation: Focus on Ischemic Stroke. Aging Dis 2024; 15:1046-1074. [PMID: 37728582 PMCID: PMC11081165 DOI: 10.14336/ad.2023.0721-1] [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: 05/03/2023] [Accepted: 07/21/2023] [Indexed: 09/21/2023] Open
Abstract
The aging of the global population poses significant scientific challenges. Moreover, the biological process of aging is the most significant risk factor for most chronic illnesses; therefore, understanding the molecular and cellular mechanisms underlying these aging-related challenges is crucial for extending the healthy lifespan of older individuals. Preventing brain aging remains a priority public health goal, and integrative and comprehensive aging analyses have revealed that immunosenescence is a potential cause of age-related brain damage and disease (e.g., stroke). Importantly, the neuroinflammatory and immune systems present two-way contact and thus can affect each other. Emerging evidence supports the numerous effects of immunosenescence- and inflammation-mediated immunity in neurologically injured brains. In this study, we briefly outline how aging alters the pathophysiology and transcriptional amplitude in patients who experienced stroke and then discuss how the immune system and its cellular components and molecular mechanisms are affected by age after stroke. Finally, we highlight emerging interventions with the potential to slow down or reduce aging and prevent stroke onset.
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Affiliation(s)
- Qiuxin Chen
- The First Affiliated Hospital of Heilongjiang University of Chinese Medicine, Harbin 150000, China
| | - Minmin Wu
- Heilongjiang University of Chinese Medicine, Harbin 150000, China
| | - Qiang Tang
- The Second Affiliated Hospital of Heilongjiang University of Chinese Medicine, Harbin 150000, China
| | - Peiyu Yan
- Faculty of Chinese Medicine, Macau University of Science and Technology, Macau 999078, China
- State Key Laboratory of Quality Research in Chinese Medicines, Macau University of Science and Technology, Macau 999078, China
| | - Luwen Zhu
- The Second Affiliated Hospital of Heilongjiang University of Chinese Medicine, Harbin 150000, China
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Al-Khateeb ZF, Boumenar H, Adebimpe J, Shekerzade S, Henson SM, Tremoleda JL, Michael-Titus AT. The cellular senescence response and neuroinflammation in juvenile mice following controlled cortical impact and repetitive mild traumatic brain injury. Exp Neurol 2024; 374:114714. [PMID: 38325653 DOI: 10.1016/j.expneurol.2024.114714] [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: 09/05/2023] [Revised: 12/11/2023] [Accepted: 02/03/2024] [Indexed: 02/09/2024]
Abstract
Traumatic brain injury (TBI) is a leading cause of disability and increases the risk of developing neurodegenerative diseases. The mechanisms linking TBI to neurodegeneration remain to be defined. It has been proposed that the induction of cellular senescence after injury could amplify neuroinflammation and induce long-term tissue changes. The induction of a senescence response post-injury in the immature brain has yet to be characterised. We carried out two types of brain injury in juvenile CD1 mice: invasive TBI using controlled cortical impact (CCI) and repetitive mild TBI (rmTBI) using weight drop injury. The analysis of senescence-related signals showed an increase in γH2AX-53BP1 nuclear foci, p53, p19ARF, and p16INK4a expression in the CCI group, 5 days post-injury (dpi). At 35 days, the difference was no longer statistically significant. Gene expression showed the activation of different senescence pathways in the ipsilateral and contralateral hemispheres in the injured mice. CCI-injured mice showed a neuroinflammatory early phase after injury (increased Iba1 and GFAP expression), which persisted for GFAP. After CCI, there was an increase at 5 days in p16INK4, whereas in rmTBI, a significant increase was seen at 35 dpi. Both injuries caused a decrease in p21 at 35 dpi. In rmTBI, other markers showed no significant change. The PCR array data predicted the activation of pathways connected to senescence after rmTBI. These results indicate the induction of a complex cellular senescence and glial reaction in the immature mouse brain, with clear differences between an invasive brain injury and a repetitive mild injury.
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Affiliation(s)
- Zahra F Al-Khateeb
- Centre for Neuroscience, Surgery and Trauma, The Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, United Kingdom.
| | - Hasna Boumenar
- Centre for Neuroscience, Surgery and Trauma, The Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, United Kingdom
| | - Joycee Adebimpe
- Centre for Neuroscience, Surgery and Trauma, The Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, United Kingdom
| | - Shenel Shekerzade
- Centre for Neuroscience, Surgery and Trauma, The Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, United Kingdom
| | - Siân M Henson
- Translational Medicine and Therapeutics, William Harvey Research Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - Jordi L Tremoleda
- Centre for Neuroscience, Surgery and Trauma, The Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, United Kingdom
| | - Adina T Michael-Titus
- Centre for Neuroscience, Surgery and Trauma, The Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, United Kingdom
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Taskina D, Zhu C, Schwab N, Hazrati LN. Brain pathology and symptoms linked to concussion history: beyond chronic traumatic encephalopathy. Brain Commun 2024; 6:fcad314. [PMID: 38560515 PMCID: PMC10977958 DOI: 10.1093/braincomms/fcad314] [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: 05/08/2023] [Revised: 10/13/2023] [Accepted: 02/23/2024] [Indexed: 04/04/2024] Open
Abstract
Repeated head trauma acquired through sports injuries has been associated with the development of long-term disabling symptoms that negatively impact the quality of life. In this retrospective case series, 52 male former professional athletes involved in contact sports and with a history of multiple concussions were evaluated for chronic clinical symptoms and post-mortem neuropathological diagnoses. The clinical symptoms of 19 cases were examined in greater detail for symptom type, severity and duration. Information on neurological, psychiatric and physical symptoms, substance use profiles and concussion histories was obtained from the athletes' next of kin and assessed in relation to post-mortem neuropathological diagnoses. Cases were categorized into three different neuropathological groups: no major neuropathological findings, the presence of only chronic traumatic encephalopathy (CTE) and the diagnosis(es) of other neurodegenerative diseases. Age at death and the presence of DNA damage in the post-mortem brains were analysed for correlation with the clinical symptoms. In this case series, 14/52 (26.9%) cases (mean age 48.2 ± 11.4) had neuropathological evidence of low-stage/low-burden CTE. A total of 11/52 (21.2%) cases (mean age 38.7 ± 12.7) presented a similar profile and severity of behavioural symptoms to those with CTE, despite the lack of significant post-mortem neuropathological findings. A total of 27/52 (51.9%) cases (mean age 75.5 ± 8.7) presented with complex post-mortem neurodegenerative diagnoses, including Alzheimer's disease and other mixed pathologies, and clinical symptoms associated with language, memory and sensory dysfunction. The presence of DNA damage in the brain was found in all neuropathological groups, predominantly in the ependymal lining of ventricles, and phosphorylated histone H2AX staining was correlated with higher age at death (r = 0.59) and symptoms of language dysfunction (r = 0.56). Findings from our case series suggest that post-concussive symptoms are not driven by CTE. Our findings show that proteinopathies alone may not account for the complexity of the clinical manifestations and suggest the possibility of other drivers, such as DNA damage, as potentially useful markers of brain trauma. Broadening the search for biological markers that reflect the effects of brain injury, even when proteinopathy is not observed, and taking a symptom-driven approach are therefore advised.
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Affiliation(s)
- Daria Taskina
- Department of Paediatric Laboratory Medicine, The Hospital for Sick Children, Toronto, Ontario M5G 1X8, Canada
| | - Cherrie Zhu
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Nicole Schwab
- Department of Paediatric Laboratory Medicine, The Hospital for Sick Children, Toronto, Ontario M5G 1X8, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Lili-Naz Hazrati
- Department of Paediatric Laboratory Medicine, The Hospital for Sick Children, Toronto, Ontario M5G 1X8, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada
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Drake SS, Mohammadnia A, Heale K, Groh AMR, Hua EML, Zaman A, Hintermayer MA, Zandee S, Gosselin D, Stratton JA, Sinclair DA, Fournier AE. Cellular rejuvenation protects neurons from inflammation mediated cell death. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.30.560301. [PMID: 37873446 PMCID: PMC10592844 DOI: 10.1101/2023.09.30.560301] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2023]
Abstract
In multiple sclerosis (MS), the invasion of the central nervous system by peripheral immune cells is followed by the activation of resident microglia and astrocytes. This cascade of events results in demyelination, which triggers neuronal damage and death. The molecular signals in neurons responsible for this damage are not yet fully characterized. In MS, retinal ganglion cell neurons (RGCs) of the central nervous system (CNS) undergo axonal injury and cell death. This phenomenon is mirrored in the experimental autoimmune encephalomyelitis (EAE) mouse model of MS. To understand the molecular landscape, we isolated RGCs from mice subjected to the EAE protocol. RNA-sequencing and ATAC-sequencing analyses were performed. Pathway analysis of the RNA-sequencing data revealed that RGCs displayed a molecular signature, similar to aged neurons, showcasing features of senescence. Single-nucleus RNA-sequencing analysis of neurons from human MS patients revealed a comparable senescence-like phenotype., which was supported by immunostaining RGCs in EAE mice. These changes include alterations to the nuclear envelope, modifications in chromatin marks, and accumulation of DNA damage. Transduction of RGCs with an Oct4 - Sox2 - Klf4 transgene to convert neurons in the EAE model to a more youthful epigenetic and transcriptomic state enhanced the survival of RGCs. Collectively, this research uncovers a previously unidentified senescent-like phenotype in neurons under pathological inflammation and neurons from MS patients. The rejuvenation of this aged transcriptome improved visual acuity and neuronal survival in the EAE model supporting the idea that age rejuvenation therapies and senotherapeutic agents could offer a direct means of neuroprotection in autoimmune disorders.
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Gard A, Vedung F, Piehl F, Khademi M, Wernersson MP, Rorsman I, Tegner Y, Pessah-Rasmussen H, Ruscher K, Marklund N. Cerebrospinal fluid levels of neuroinflammatory biomarkers are increased in athletes with persistent post-concussive symptoms following sports-related concussion. J Neuroinflammation 2023; 20:189. [PMID: 37592277 PMCID: PMC10433539 DOI: 10.1186/s12974-023-02864-0] [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: 05/17/2023] [Accepted: 07/29/2023] [Indexed: 08/19/2023] Open
Abstract
A sports-related concussion (SRC) is often caused by rapid head rotation at impact, leading to shearing and stretching of axons in the white matter and initiation of secondary inflammatory processes that may exacerbate the initial injury. We hypothesized that athletes with persistent post-concussive symptoms (PPCS) display signs of ongoing neuroinflammation, as reflected by altered profiles of cerebrospinal fluid (CSF) biomarkers, in turn relating to symptom severity. We recruited athletes with PPCS preventing sports participation as well as limiting work, school and/or social activities for ≥ 6 months for symptom rating using the Sport Concussion Assessment Tool, version 5 (SCAT-5) and for cognitive assessment using the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS). Following a spinal tap, we analysed 27 CSF inflammatory biomarkers (pro-inflammatory chemokines and cytokine panels) by a multiplex immunoassay using antibodies as electrochemiluminescent labels to quantify concentrations in PPCS athletes, and in healthy age- and sex-matched controls exercising ≤ 2 times/week at low-to-moderate intensity. Thirty-six subjects were included, 24 athletes with PPCS and 12 controls. The SRC athletes had sustained a median of five concussions, the most recent at a median of 17 months prior to the investigation. CSF cytokines and chemokines levels were significantly increased in eight (IL-2, TNF-α, IL-15, TNF-β, VEGF, Eotaxin, IP-10, and TARC), significantly decreased in one (Eotaxin-3), and unaltered in 16 in SRC athletes when compared to controls, and two were un-detectable. The SRC athletes reported many and severe post-concussive symptoms on SCAT5, and 10 out of 24 athletes performed in the impaired range (Z < - 1.5) on cognitive testing. Individual biomarker concentrations did not strongly correlate with symptom rating or cognitive function. Limitations include evaluation at a single post-injury time point in relatively small cohorts, and no control group of concussed athletes without persisting symptoms was included. Based on CSF inflammatory marker profiling we find signs of ongoing neuroinflammation persisting months to years after the last SRC in athletes with persistent post-concussive symptoms. Since an ongoing inflammatory response may exacerbate the brain injury these results encourage studies of treatments targeting the post-injury inflammatory response in sports-related concussion.
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Affiliation(s)
- Anna Gard
- Department of Clinical Sciences Lund, Neurosurgery, Lund University, Lund, Sweden
| | - Fredrik Vedung
- Department of Neuroscience, Neurosurgery, Uppsala University, Uppsala, Sweden
| | - Fredrik Piehl
- Department of Clinical Neuroscience, Neuroimmunology Unit, Karolinska Institute, Karolinska University Hospital, Stockholm, Sweden
| | - Mohsen Khademi
- Department of Clinical Neuroscience, Neuroimmunology Unit, Karolinska Institute, Karolinska University Hospital, Stockholm, Sweden
| | | | - Ia Rorsman
- Department of Neurology and Rehabilitation Medicine, Skåne University Hospital, Lund, Sweden
| | - Yelverton Tegner
- Department of Health Sciences, Luleå University of Technology, Luleå, Sweden
| | - Hélène Pessah-Rasmussen
- Department of Neurology and Rehabilitation Medicine, Skåne University Hospital, Lund, Sweden
- Department of Clinical Sciences Lund, Neurology, Lund University, Lund, Sweden
| | - Karsten Ruscher
- Department of Clinical Sciences Lund, Neurosurgery, Lund University, Lund, Sweden
| | - Niklas Marklund
- Department of Clinical Sciences Lund, Neurosurgery, Lund University, Lund, Sweden
- Department of Clinical Sciences Lund, Neurosurgery, Lund University, Skåne University Hospital EA-Blocket Plan 4, Klinikgatan 17A7, 221 85 Lund, Sweden
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Leung E, Taskina D, Schwab N, Hazrati LN. BRCA1 heterozygosity promotes DNA damage-induced senescence in a sex-specific manner following repeated mild traumatic brain injury. Front Neurosci 2023; 17:1225226. [PMID: 37638313 PMCID: PMC10450634 DOI: 10.3389/fnins.2023.1225226] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Accepted: 07/21/2023] [Indexed: 08/29/2023] Open
Abstract
Emerging evidence suggests cellular senescence, as a consequence of excess DNA damage and deficient repair, to be a driver of brain dysfunction following repeated mild traumatic brain injury (rmTBI). This study aimed to further investigate the role of deficient DNA repair, specifically BRCA1-related repair, on DNA damage-induced senescence. BRCA1, a repair protein involved in maintaining genomic integrity with multiple roles in the central nervous system, was previously reported to be significantly downregulated in post-mortem brains with a history of rmTBI. Here we examined the effects of impaired BRCA1-related repair on DNA damage-induced senescence and outcomes 1-week post-rmTBI using mice with a heterozygous knockout for BRCA1 in a sex-segregated manner. Altered BRCA1 repair with rmTBI resulted in altered anxiety-related behaviours in males and females using elevated zero maze and contextual fear conditioning. Evaluating molecular markers associated with DNA damage signalling and senescence-related pathways revealed sex-specific differences attributed to BRCA1, where females exhibited elevated DNA damage, impaired DNA damage signalling, and dampened senescence onset compared to males. Overall, the results from this study highlight sex-specific consequences of aberrant DNA repair on outcomes post-injury, and further support a need to develop sex-specific treatments following rmTBI.
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Affiliation(s)
- Emily Leung
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada
- Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, ON, Canada
| | - Daria Taskina
- Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, ON, Canada
| | - Nicole Schwab
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada
- Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, ON, Canada
| | - Lili-Naz Hazrati
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada
- Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, ON, Canada
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Chojak R, Fares J, Petrosyan E, Lesniak MS. Cellular senescence in glioma. J Neurooncol 2023; 164:11-29. [PMID: 37458855 DOI: 10.1007/s11060-023-04387-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Accepted: 07/01/2023] [Indexed: 08/29/2023]
Abstract
INTRODUCTION Glioma is the most common primary brain tumor and is often associated with treatment resistance and poor prognosis. Standard treatment typically involves radiotherapy and temozolomide-based chemotherapy, both of which induce cellular senescence-a tumor suppression mechanism. DISCUSSION Gliomas employ various mechanisms to bypass or escape senescence and remain in a proliferative state. Importantly, senescent cells remain viable and secrete a large number of factors collectively known as the senescence-associated secretory phenotype (SASP) that, paradoxically, also have pro-tumorigenic effects. Furthermore, senescent cells may represent one form of tumor dormancy and play a role in glioma recurrence and progression. CONCLUSION In this article, we delineate an overview of senescence in the context of gliomas, including the mechanisms that lead to senescence induction, bypass, and escape. Furthermore, we examine the role of senescent cells in the tumor microenvironment and their role in tumor progression and recurrence. Additionally, we highlight potential therapeutic opportunities for targeting senescence in glioma.
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Affiliation(s)
- Rafał Chojak
- Department of Neurological Surgery, Feinberg School of Medicine, Northwestern University, 676 N. St Clair Street, Suite 2210, Chicago, IL, 60611, USA
- Northwestern Medicine Malnati Brain Tumor Institute, Lurie Comprehensive Cancer Center, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Jawad Fares
- Department of Neurological Surgery, Feinberg School of Medicine, Northwestern University, 676 N. St Clair Street, Suite 2210, Chicago, IL, 60611, USA
- Northwestern Medicine Malnati Brain Tumor Institute, Lurie Comprehensive Cancer Center, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Edgar Petrosyan
- Department of Neurological Surgery, Feinberg School of Medicine, Northwestern University, 676 N. St Clair Street, Suite 2210, Chicago, IL, 60611, USA
- Northwestern Medicine Malnati Brain Tumor Institute, Lurie Comprehensive Cancer Center, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Maciej S Lesniak
- Department of Neurological Surgery, Feinberg School of Medicine, Northwestern University, 676 N. St Clair Street, Suite 2210, Chicago, IL, 60611, USA.
- Northwestern Medicine Malnati Brain Tumor Institute, Lurie Comprehensive Cancer Center, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA.
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Wang J, Lu Y, Carr C, Dhandapani KM, Brann DW. Senolytic therapy is neuroprotective and improves functional outcome long-term after traumatic brain injury in mice. Front Neurosci 2023; 17:1227705. [PMID: 37575310 PMCID: PMC10416099 DOI: 10.3389/fnins.2023.1227705] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Accepted: 07/10/2023] [Indexed: 08/15/2023] Open
Abstract
Introduction Chronic neuroinflammation can exist for months to years following traumatic brain injury (TBI), although the underlying mechanisms remain poorly understood. Methods In the current study, we used a controlled cortical impact mouse model of TBI to examine whether proinflammatory senescent cells are present in the brain long-term (months) after TBI and whether ablation of these cells via administration of senolytic drugs can improve long-term functional outcome after TBI. The results revealed that astrocytes and microglia in the cerebral cortex, hippocampus, corpus callosum and lateral posterior thalamus colocalized the senescent cell markers, p16Ink4a or p21Cip1/Waf1 at 5 weeks post injury (5wpi) and 4 months post injury (4mpi) in a controlled cortical impact (CCI) model. Intermittent administration of the senolytic drugs, dasatinib and quercetin (D + Q) beginning 1-month after TBI for 13 weeks significantly ablated p16Ink4a-positive- and p21Cip1/Waf1-positive-cells in the brain of TBI animals, and significantly reduced expression of the major senescence-associated secretory phenotype (SASP) pro-inflammatory factors, interleukin-1β and interleukin-6. Senolytic treatment also significantly attenuated neurodegeneration and enhanced neuron number at 18 weeks after TBI in the ipsilateral cortex, hippocampus, and lateral posterior thalamus. Behavioral testing at 18 weeks after TBI further revealed that senolytic therapy significantly rescued defects in spatial reference memory and recognition memory, as well as depression-like behavior in TBI mice. Discussion Taken as a whole, these findings indicate there is robust and widespread induction of senescent cells in the brain long-term after TBI, and that senolytic drug treatment begun 1-month after TBI can efficiently ablate the senescent cells, reduce expression of proinflammatory SASP factors, reduce neurodegeneration, and rescue defects in reference memory, recognition memory, and depressive behavior.
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Affiliation(s)
| | | | | | | | - Darrell W. Brann
- Department of Neurosurgery, Medical College of Georgia, Augusta University, Augusta, GA, United States
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Nelles DG, Hazrati LN. The pathological potential of ependymal cells in mild traumatic brain injury. Front Cell Neurosci 2023; 17:1216420. [PMID: 37396927 PMCID: PMC10312375 DOI: 10.3389/fncel.2023.1216420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Accepted: 06/05/2023] [Indexed: 07/04/2023] Open
Abstract
Mild traumatic brain injury (mTBI) is a common neurological condition affecting millions of individuals worldwide. Although the pathology of mTBI is not fully understood, ependymal cells present a promising approach for studying the pathogenesis of mTBI. Previous studies have revealed that DNA damage in the form of γH2AX accumulates in ependymal cells following mTBI, with evidence of widespread cellular senescence in the brain. Ependymal ciliary dysfunction has also been observed, leading to altered cerebrospinal fluid homeostasis. Even though ependymal cells have not been extensively studied in the context of mTBI, these observations reflect the pathological potential of ependymal cells that may underlie the neuropathological and clinical presentations of mTBI. This mini review explores the molecular and structural alterations that have been reported in ependymal cells following mTBI, as well as the potential pathological mechanisms mediated by ependymal cells that may contribute to overall dysfunction of the brain post-mTBI. Specifically, we address the topics of DNA damage-induced cellular senescence, dysregulation of cerebrospinal fluid homeostasis, and the consequences of impaired ependymal cell barriers. Moreover, we highlight potential ependymal cell-based therapies for the treatment of mTBI, with a focus on neurogenesis, ependymal cell repair, and modulation of senescence signaling pathways. Further insight and research in this field will help to establish the role of ependymal cells in the pathogenesis of mTBI and may lead to improved treatments that leverage ependymal cells to target the origins of mTBI pathology.
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Affiliation(s)
- Diana G. Nelles
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada
- The Hospital for Sick Children, Toronto, ON, Canada
| | - Lili-Naz Hazrati
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada
- The Hospital for Sick Children, Toronto, ON, Canada
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11
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Lu Y, Jarrahi A, Moore N, Bartoli M, Brann DW, Baban B, Dhandapani KM. Inflammaging, cellular senescence, and cognitive aging after traumatic brain injury. Neurobiol Dis 2023; 180:106090. [PMID: 36934795 PMCID: PMC10763650 DOI: 10.1016/j.nbd.2023.106090] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Revised: 03/01/2023] [Accepted: 03/16/2023] [Indexed: 03/19/2023] Open
Abstract
Traumatic brain injury (TBI) is associated with mortality and morbidity worldwide. Accumulating pre-clinical and clinical data suggests TBI is the leading extrinsic cause of progressive neurodegeneration. Neurological deterioration after either a single moderate-severe TBI or repetitive mild TBI often resembles dementia in aged populations; however, no currently approved therapies adequately mitigate neurodegeneration. Inflammation correlates with neurodegenerative changes and cognitive dysfunction for years post-TBI, suggesting a potential association between immune activation and both age- and TBI-induced cognitive decline. Inflammaging, a chronic, low-grade sterile inflammation associated with natural aging, promotes cognitive decline. Cellular senescence and the subsequent development of a senescence associated secretory phenotype (SASP) promotes inflammaging and cognitive aging, although the functional association between senescent cells and neurodegeneration is poorly defined after TBI. In this mini-review, we provide an overview of the pre-clinical and clinical evidence linking cellular senescence with poor TBI outcomes. We also discuss the current knowledge and future potential for senotherapeutics, including senolytics and senomorphics, which kill and/or modulate senescent cells, as potential therapeutics after TBI.
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Affiliation(s)
- Yujiao Lu
- Department of Neurosurgery, Medical College of Georgia, Augusta University, Augusta, GA 30912, United States of America.
| | - Abbas Jarrahi
- Department of Neurosurgery, Medical College of Georgia, Augusta University, Augusta, GA 30912, United States of America
| | - Nicholas Moore
- Department of Neurosurgery, Medical College of Georgia, Augusta University, Augusta, GA 30912, United States of America
| | - Manuela Bartoli
- Department of Ophthalmology, Medical College of Georgia, Augusta University, Augusta, GA 30912, United States of America
| | - Darrell W Brann
- Department of Neurosurgery, Medical College of Georgia, Augusta University, Augusta, GA 30912, United States of America
| | - Babak Baban
- Department of Oral Biology and Diagnostic Services, Dental College of Georgia, Augusta University, Augusta, GA 30912, United States of America
| | - Krishnan M Dhandapani
- Department of Neurosurgery, Medical College of Georgia, Augusta University, Augusta, GA 30912, United States of America.
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12
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Ng PY, McNeely TL, Baker DJ. Untangling senescent and damage-associated microglia in the aging and diseased brain. FEBS J 2023; 290:1326-1339. [PMID: 34873840 PMCID: PMC9167891 DOI: 10.1111/febs.16315] [Citation(s) in RCA: 21] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Revised: 11/16/2021] [Accepted: 12/06/2021] [Indexed: 01/10/2023]
Abstract
Microglial homeostasis has emerged as a critical mediator of health and disease in the central nervous system. In their neuroprotective role as the predominant immune cells of the brain, microglia surveil the microenvironment for debris and pathogens, while also promoting neurogenesis and performing maintenance on synapses. Chronological ageing, disease onset, or traumatic injury promotes irreparable damage or deregulated signaling to reinforce neurotoxic phenotypes in microglia. These insults may include cellular senescence, a stable growth arrest often accompanied by the production of a distinctive pro-inflammatory secretory phenotype, which may contribute to age- or disease-driven decline in neuronal health and cognition and is a potential novel therapeutic target. Despite this increased scrutiny, unanswered questions remain about what distinguishes senescent microglia and non-senescent microglia reacting to insults occurring in ageing, disease, and injury, and how central the development of senescence is in their pivot from guardian to assailant. To intelligently design future studies to untangle senescent microglia from other primed and reactionary states, specific criteria must be developed that define this population and allow for comparisons between different model systems. Comparing microglial activity seen in homeostasis, ageing, disease, and injury allows for a more coherent understanding of when and how senescent and other harmful microglial subpopulations should be targeted.
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Affiliation(s)
- Pei Y Ng
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN, USA
| | - Taylor L McNeely
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN, USA
| | - Darren J Baker
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN, USA.,Department of Pediatric and Adolescent Medicine, Mayo Clinic, Rochester, MN, USA
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Nelles DG, Hazrati LN. Ependymal cells and neurodegenerative disease: outcomes of compromised ependymal barrier function. Brain Commun 2022; 4:fcac288. [PMID: 36415662 PMCID: PMC9677497 DOI: 10.1093/braincomms/fcac288] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Revised: 09/13/2022] [Accepted: 11/01/2022] [Indexed: 08/08/2023] Open
Abstract
Within the central nervous system, ependymal cells form critical components of the blood-cerebrospinal fluid barrier and the cerebrospinal fluid-brain barrier. These barriers provide biochemical, immunological and physical protection against the entry of molecules and foreign substances into the cerebrospinal fluid while also regulating cerebrospinal fluid dynamics, such as the composition, flow and removal of waste from the cerebrospinal fluid. Previous research has demonstrated that several neurodegenerative diseases, such as Alzheimer's disease and multiple sclerosis, display irregularities in ependymal cell function, morphology, gene expression and metabolism. Despite playing key roles in maintaining overall brain health, ependymal barriers are largely overlooked and understudied in the context of disease, thus limiting the development of novel diagnostic and treatment options. Therefore, this review explores the anatomical properties, functions and structures that define ependymal cells in the healthy brain, as well as the ways in which ependymal cell dysregulation manifests across several neurodegenerative diseases. Specifically, we will address potential mechanisms, causes and consequences of ependymal cell dysfunction and describe how compromising the integrity of ependymal barriers may initiate, contribute to, or drive widespread neurodegeneration in the brain.
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Affiliation(s)
- Diana G Nelles
- Department of Laboratory Medicine and Pathobiology, University of Toronto, 1 King’s College Circle, Toronto, ON M5S 1A8, Canada
- Department of Paediatric Laboratory Medicine, The Hospital for Sick Children, 555 University Ave, Canada
| | - Lili-Naz Hazrati
- Correspondence to: Dr. Lili-Naz Hazrati 555 University Ave, Toronto ON M5G 1X8, Canada E-mail:
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Schwab N, Taskina D, Leung E, Innes BT, Bader GD, Hazrati LN. Neurons and glial cells acquire a senescent signature after repeated mild traumatic brain injury in a sex-dependent manner. Front Neurosci 2022; 16:1027116. [PMID: 36408415 PMCID: PMC9669743 DOI: 10.3389/fnins.2022.1027116] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Accepted: 09/23/2022] [Indexed: 08/15/2023] Open
Abstract
Mild traumatic brain injury (mTBI) is an important public health issue, as it can lead to long-term neurological symptoms and risk of neurodegenerative disease. The pathophysiological mechanisms driving this remain unclear, and currently there are no effective therapies for mTBI. In this study on repeated mTBI (rmTBI), we have induced three mild closed-skull injuries or sham procedures, separated by 24 h, in C57BL/6 mice. We show that rmTBI mice have prolonged righting reflexes and astrogliosis, with neurological impairment in the Morris water maze (MWM) and the light dark test. Cortical and hippocampal tissue analysis revealed DNA damage in the form of double-strand breaks, oxidative damage, and R-loops, markers of cellular senescence including p16 and p21, and signaling mediated by the cGAS-STING pathway. This study identified novel sex differences after rmTBI in mice. Although these markers were all increased by rmTBI in both sexes, females had higher levels of DNA damage, lower levels of the senescence protein p16, and lower levels of cGAS-STING signaling proteins compared to their male counterparts. Single-cell RNA sequencing of the male rmTBI mouse brain revealed activation of the DNA damage response, evidence of cellular senescence, and pro-inflammatory markers reminiscent of the senescence-associated secretory phenotype (SASP) in neurons and glial cells. Cell-type specific changes were also present with evidence of brain immune activation, neurotransmission alterations in both excitatory and inhibitory neurons, and vascular dysfunction. Treatment of injured mice with the senolytic drug ABT263 significantly reduced markers of senescence only in males, but was not therapeutic in females. The reduction of senescence by ABT263 in male mice was accompanied by significantly improved performance in the MWM. This study provides compelling evidence that senescence contributes to brain dysfunction after rmTBI, but may do so in a sex-dependent manner.
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Affiliation(s)
- Nicole Schwab
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada
- Program in Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, ON, Canada
| | - Daria Taskina
- Program in Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, ON, Canada
| | - Emily Leung
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada
- Program in Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, ON, Canada
| | - Brendan T. Innes
- The Donnelly Centre, University of Toronto, Toronto, ON, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Gary D. Bader
- The Donnelly Centre, University of Toronto, Toronto, ON, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Lili-Naz Hazrati
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada
- Program in Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, ON, Canada
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15
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Evidence of Sex Differences in Cellular Senescence. Neurobiol Aging 2022; 120:88-104. [DOI: 10.1016/j.neurobiolaging.2022.08.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Revised: 08/30/2022] [Accepted: 08/30/2022] [Indexed: 11/20/2022]
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16
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Ritzel RM, Li Y, Lei Z, Carter J, He J, Choi HMC, Khan N, Li H, Allen S, Lipinski MM, Faden AI, Wu J. Functional and transcriptional profiling of microglial activation during the chronic phase of TBI identifies an age-related driver of poor outcome in old mice. GeroScience 2022; 44:1407-1440. [PMID: 35451674 PMCID: PMC9213636 DOI: 10.1007/s11357-022-00562-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Accepted: 04/01/2022] [Indexed: 12/14/2022] Open
Abstract
Elderly patients with traumatic brain injury (TBI) have greater mortality and poorer outcomes than younger individuals. The extent to which old age alters long-term recovery and chronic microglial activation after TBI is unknown, and evidence for therapeutic efficacy in aged mice is sorely lacking. The present study sought to identify potential inflammatory mechanisms underlying age-related outcomes late after TBI. Controlled cortical impact was used to induce moderate TBI in young and old male C57BL/6 mice. At 12 weeks post-injury, aged mice exhibited higher mortality, poorer functional outcomes, larger lesion volumes, and increased microglial activation. Transcriptomic analysis identified age- and TBI-specific gene changes consistent with a disease-associated microglial signature in the chronically injured brain, including those involved with complement, phagocytosis, and autophagy pathways. Dysregulation of phagocytic and autophagic function in microglia was accompanied by increased neuroinflammation in old mice. As proof-of-principle that these pathways have functional importance, we administered an autophagic enhancer, trehalose, in drinking water continuously for 8 weeks after TBI. Old mice treated with trehalose showed enhanced functional recovery and reduced microglial activation late after TBI compared to the sucrose control group. Our data indicate that microglia undergo chronic changes in autophagic regulation with both normal aging and TBI that are associated with poorer functional outcome. Enhancing autophagy may therefore be a promising clinical therapeutic strategy for TBI, especially in older patients.
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Affiliation(s)
- Rodney M. Ritzel
- Department of Anesthesiology and Shock, Trauma and Anesthesiology Research Center, University of Maryland School of Medicine, Baltimore, MD 21201 USA
| | - Yun Li
- Department of Anesthesiology and Shock, Trauma and Anesthesiology Research Center, University of Maryland School of Medicine, Baltimore, MD 21201 USA
| | - Zhuofan Lei
- Department of Anesthesiology and Shock, Trauma and Anesthesiology Research Center, University of Maryland School of Medicine, Baltimore, MD 21201 USA
| | - Jordan Carter
- Department of Anesthesiology and Shock, Trauma and Anesthesiology Research Center, University of Maryland School of Medicine, Baltimore, MD 21201 USA
| | - Junyun He
- Department of Anesthesiology and Shock, Trauma and Anesthesiology Research Center, University of Maryland School of Medicine, Baltimore, MD 21201 USA
| | - Harry M. C. Choi
- Department of Anesthesiology and Shock, Trauma and Anesthesiology Research Center, University of Maryland School of Medicine, Baltimore, MD 21201 USA
| | - Niaz Khan
- Department of Anesthesiology and Shock, Trauma and Anesthesiology Research Center, University of Maryland School of Medicine, Baltimore, MD 21201 USA
| | - Hui Li
- Department of Anesthesiology and Shock, Trauma and Anesthesiology Research Center, University of Maryland School of Medicine, Baltimore, MD 21201 USA
| | - Samantha Allen
- Department of Anesthesiology and Shock, Trauma and Anesthesiology Research Center, University of Maryland School of Medicine, Baltimore, MD 21201 USA
| | - Marta M. Lipinski
- Department of Anesthesiology and Shock, Trauma and Anesthesiology Research Center, University of Maryland School of Medicine, Baltimore, MD 21201 USA
| | - Alan I. Faden
- Department of Anesthesiology and Shock, Trauma and Anesthesiology Research Center, University of Maryland School of Medicine, Baltimore, MD 21201 USA
| | - Junfang Wu
- Department of Anesthesiology and Shock, Trauma and Anesthesiology Research Center, University of Maryland School of Medicine, Baltimore, MD 21201 USA
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Gonzales MM, Krishnamurthy S, Garbarino V, Daeihagh AS, Gillispie GJ, Deep G, Craft S, Orr ME. A geroscience motivated approach to treat Alzheimer's disease: Senolytics move to clinical trials. Mech Ageing Dev 2021; 200:111589. [PMID: 34687726 PMCID: PMC9059898 DOI: 10.1016/j.mad.2021.111589] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 10/04/2021] [Accepted: 10/18/2021] [Indexed: 12/29/2022]
Abstract
The pathogenic processes driving Alzheimer's disease (AD) are complex. An incomplete understanding of underlying disease mechanisms has presented insurmountable obstacles for developing effective disease-modifying therapies. Advanced chronological age is the greatest risk factor for developing AD. Intervening on biological aging may alter disease progression and represents a novel, complementary approach to current strategies. Toward this end, cellular senescence has emerged as a promising target. This complex stress response harbors damaged cells in a cell cycle arrested, apoptosis-resistant cell state. Senescent cells accumulate with age where they notoriously secrete molecules that contribute to chronic tissue dysfunction and disease. Thus, benefits of cell survival in a senescent fate are countered by their toxic secretome. The removal of senescent cells improves brain structure and function in rodent models at risk of developing AD, and in those with advanced Aβ and tau pathology. The present review describes the path to translating this promising treatment strategy to AD clinical trials. We review evidence for senescent cell accumulation in the human brain, considerations and strategies for senescence-targeting trials specific to AD, approaches to detect senescent brain cells in biofluids, and summarize the goals of the first senolytic trials for the treatment of AD (NCT04063124 and NCT04685590). This article is part of the Special Issue - Senolytics - Edited by Joao Passos and Diana Jurk.
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Affiliation(s)
- Mitzi M Gonzales
- Glenn Biggs Institute for Alzheimer's and Neurodegenerative Diseases, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA
| | - Sudarshan Krishnamurthy
- Department of Internal Medicine, Section on Gerontology and Geriatric Medicine, Wake Forest School of Medicine, Winston-Salem, NC, USA; Bowman Gray Center for Medical Education, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | - Valentina Garbarino
- Glenn Biggs Institute for Alzheimer's and Neurodegenerative Diseases, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA
| | - Ali S Daeihagh
- Department of Internal Medicine, Section on Gerontology and Geriatric Medicine, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | - Gregory J Gillispie
- Department of Internal Medicine, Section on Gerontology and Geriatric Medicine, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | - Gagan Deep
- Department of Cancer Biology, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | - Suzanne Craft
- Department of Internal Medicine, Section on Gerontology and Geriatric Medicine, Wake Forest School of Medicine, Winston-Salem, NC, USA; Sticht Center for Healthy Aging and Alzheimer's Prevention, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | - Miranda E Orr
- Department of Internal Medicine, Section on Gerontology and Geriatric Medicine, Wake Forest School of Medicine, Winston-Salem, NC, USA; Sticht Center for Healthy Aging and Alzheimer's Prevention, Wake Forest School of Medicine, Winston-Salem, NC, USA; Salisbury VA Medical Center, Salisbury, NC, USA.
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18
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Gonzales MM, Krishnamurthy S, Garbarino V, Daeihagh AS, Gillispie GJ, Deep G, Craft S, Orr ME. A geroscience motivated approach to treat Alzheimer’s disease: Senolytics move to clinical trials. Mech Ageing Dev 2021. [DOI: 10.1016/j.mad.2021.111589
expr 868687188 + 807217478] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/16/2023]
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19
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Phybrata Sensors and Machine Learning for Enhanced Neurophysiological Diagnosis and Treatment. SENSORS 2021; 21:s21217417. [PMID: 34770729 PMCID: PMC8587627 DOI: 10.3390/s21217417] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Revised: 11/03/2021] [Accepted: 11/03/2021] [Indexed: 11/29/2022]
Abstract
Concussion injuries remain a significant public health challenge. A significant unmet clinical need remains for tools that allow related physiological impairments and longer-term health risks to be identified earlier, better quantified, and more easily monitored over time. We address this challenge by combining a head-mounted wearable inertial motion unit (IMU)-based physiological vibration acceleration (“phybrata”) sensor and several candidate machine learning (ML) models. The performance of this solution is assessed for both binary classification of concussion patients and multiclass predictions of specific concussion-related neurophysiological impairments. Results are compared with previously reported approaches to ML-based concussion diagnostics. Using phybrata data from a previously reported concussion study population, four different machine learning models (Support Vector Machine, Random Forest Classifier, Extreme Gradient Boost, and Convolutional Neural Network) are first investigated for binary classification of the test population as healthy vs. concussion (Use Case 1). Results are compared for two different data preprocessing pipelines, Time-Series Averaging (TSA) and Non-Time-Series Feature Extraction (NTS). Next, the three best-performing NTS models are compared in terms of their multiclass prediction performance for specific concussion-related impairments: vestibular, neurological, both (Use Case 2). For Use Case 1, the NTS model approach outperformed the TSA approach, with the two best algorithms achieving an F1 score of 0.94. For Use Case 2, the NTS Random Forest model achieved the best performance in the testing set, with an F1 score of 0.90, and identified a wider range of relevant phybrata signal features that contributed to impairment classification compared with manual feature inspection and statistical data analysis. The overall classification performance achieved in the present work exceeds previously reported approaches to ML-based concussion diagnostics using other data sources and ML models. This study also demonstrates the first combination of a wearable IMU-based sensor and ML model that enables both binary classification of concussion patients and multiclass predictions of specific concussion-related neurophysiological impairments.
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20
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Schwab N, Leung E, Hazrati LN. Cellular Senescence in Traumatic Brain Injury: Evidence and Perspectives. Front Aging Neurosci 2021; 13:742632. [PMID: 34650425 PMCID: PMC8505896 DOI: 10.3389/fnagi.2021.742632] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Accepted: 09/03/2021] [Indexed: 12/14/2022] Open
Abstract
Mild traumatic brain injury (mTBI) can lead to long-term neurological dysfunction and increase one's risk of neurodegenerative disease. Several repercussions of mTBI have been identified and well-studied, including neuroinflammation, gliosis, microgliosis, excitotoxicity, and proteinopathy – however the pathophysiological mechanisms activating these pathways after mTBI remains controversial and unclear. Emerging research suggests DNA damage-induced cellular senescence as a possible driver of mTBI-related sequalae. Cellular senescence is a state of chronic cell-cycle arrest and inflammation associated with physiological aging, mood disorders, dementia, and various neurodegenerative pathologies. This narrative review evaluates the existing studies which identify DNA damage or cellular senescence after TBI (including mild, moderate, and severe TBI) in both experimental animal models and human studies, and outlines how cellular senescence may functionally explain both the molecular and clinical manifestations of TBI. Studies on this subject clearly show accumulation of various forms of DNA damage (including oxidative damage, single-strand breaks, and double-strand breaks) and senescent cells after TBI, and indicate that cellular senescence may be an early event after TBI. Further studies are required to understand the role of sex, cell-type specific mechanisms, and temporal patterns, as senescence may be a pathway of interest to target for therapeutic purposes including prognosis and treatment.
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Affiliation(s)
- Nicole Schwab
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada.,The Hospital for Sick Children, Toronto, ON, Canada
| | - Emily Leung
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada.,The Hospital for Sick Children, Toronto, ON, Canada
| | - Lili-Naz Hazrati
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada.,The Hospital for Sick Children, Toronto, ON, Canada
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21
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McCunn P, Xu X, Moszczynski A, Li A, Brown A, Bartha R. Neurite orientation dispersion and density imaging in a rodent model of acute mild traumatic brain injury. J Neuroimaging 2021; 31:879-892. [PMID: 34473386 DOI: 10.1111/jon.12917] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Revised: 07/24/2021] [Accepted: 07/27/2021] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND AND PURPOSE Identification of changesin brain microstructure following mild traumatic brain injury (mTBI) could be instrumental in understanding the underlying pathophysiology. The purpose of this study was to apply neurite orientation dispersion and density imaging (NODDI) to a rodent model of mTBI to determine whether microstructural changes could be detected immediately following injury. METHODS Fifteen adult male Wistar rats were scanned on a Bruker 9.4 Tesla small animal MRI using a multi-shell acquisition (30 b = 1000 s/mm2 and 60 b = 2000 s/mm2 ). Nine animals experienced a single closed head controlled cortical impact followed by NODDI from 1 to 4 h post injury. Region of interest analysis focused on the corpus callosum and hippocampus. A mixed analysis of variance (ANOVA) was used to determine statistically significant interactions in neurite density index (NDI), orientation dispersion index (ODI), fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity. Follow up repeated-measures ANOVAs were used to determine individual changes over time. RESULTS NDI showed a significant increase in the hippocampus and corpus callosum following injury, while ODI showed increases in the corpus callosum. No significant changes were observed in the sham control animals. No changes were found in FA, MD, AD, or RD. Histological analysis revealed increased glial fibrillary acidic protein staining relative to controls in both the hippocampus and corpus callosum, with evidence of activated astrocytes in these regions. CONCLUSIONS Changes in NODDI metrics were detected as early as 1 h following mTBI. No changes were detected with conventional diffusion tensor imaging (DTI) metrics, suggesting that NODDI provides greater sensitivity to microstructural changes than conventional DTI.
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Affiliation(s)
- Patrick McCunn
- Robarts Research Institute, University of Western Ontario, London, Ontario, Canada.,Department of Medical Biophysics, University of Western Ontario, London, Ontario, Canada
| | - Xiaoyun Xu
- Robarts Research Institute, University of Western Ontario, London, Ontario, Canada
| | | | - Alex Li
- Robarts Research Institute, University of Western Ontario, London, Ontario, Canada.,Department of Medical Biophysics, University of Western Ontario, London, Ontario, Canada.,Departments of Psychiatry and Medical Imaging, University of Western Ontario, London, Ontario, Canada
| | - Arthur Brown
- Robarts Research Institute, University of Western Ontario, London, Ontario, Canada.,Department of Neuroscience, University of Western Ontario, London, Ontario, Canada
| | - Robert Bartha
- Robarts Research Institute, University of Western Ontario, London, Ontario, Canada.,Department of Medical Biophysics, University of Western Ontario, London, Ontario, Canada.,Department of Anatomy and Cell Biology, University of Western Ontario, London, Ontario, Canada
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22
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Mester JR, Bazzigaluppi P, Dorr A, Beckett T, Burke M, McLaurin J, Sled JG, Stefanovic B. Attenuation of tonic inhibition prevents chronic neurovascular impairments in a Thy1-ChR2 mouse model of repeated, mild traumatic brain injury. Am J Cancer Res 2021; 11:7685-7699. [PMID: 34335958 PMCID: PMC8315057 DOI: 10.7150/thno.60190] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2021] [Accepted: 06/04/2021] [Indexed: 12/24/2022] Open
Abstract
Rationale: Mild traumatic brain injury (mTBI), the most common type of brain trauma, frequently leads to chronic cognitive and neurobehavioral deficits. Intervening effectively is impeded by our poor understanding of its pathophysiological sequelae. Methods: To elucidate the long-term neurovascular sequelae of mTBI, we combined optogenetics, two-photon fluorescence microscopy, and intracortical electrophysiological recordings in mice to selectively stimulate peri-contusional neurons weeks following repeated closed-head injury and probe individual vessel's function and local neuronal reactivity. Results: Compared to sham-operated animals, mTBI mice showed doubled cortical venular speeds (115 ± 25%) and strongly elevated cortical venular reactivity (53 ± 17%). Concomitantly, the pericontusional neurons exhibited attenuated spontaneous activity (-57 ± 79%) and decreased reactivity (-47 ± 28%). Post-mortem immunofluorescence revealed signs of peri-contusional senescence and DNA damage, in the absence of neuronal loss or gliosis. Alteration of neuronal and vascular functioning was largely prevented by chronic, low dose, systemic administration of a GABA-A receptor inverse agonist (L-655,708), commencing 3 days following the third impact. Conclusions: Our findings indicate that repeated mTBI leads to dramatic changes in the neurovascular unit function and that attenuation of tonic inhibition can prevent these alterations. The sustained disruption of the neurovascular function may underlie the concussed brain's long-term susceptibility to injury, and calls for development of better functional assays as well as of neurovascularly targeted interventions.
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23
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Leung E, Hazrati LN. Breast cancer type 1 and neurodegeneration: consequences of deficient DNA repair. Brain Commun 2021; 3:fcab117. [PMID: 34222870 PMCID: PMC8242133 DOI: 10.1093/braincomms/fcab117] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 04/09/2021] [Accepted: 04/13/2021] [Indexed: 12/20/2022] Open
Abstract
Numerous cellular processes, including toxic protein aggregation and oxidative stress, have been studied extensively as potential mechanisms underlying neurodegeneration. However, limited therapeutic efficacy targeting these processes has prompted other mechanisms to be explored. Previous research has emphasized a link between cellular senescence and neurodegeneration, where senescence induced by excess DNA damage and deficient DNA repair results in structural and functional changes that ultimately contribute to brain dysfunction and increased vulnerability for neurodegeneration. Specific DNA repair proteins, such as breast cancer type 1, have been associated with both stress-induced senescence and neurodegenerative diseases, however, specific mechanisms remain unclear. Therefore, this review explores DNA damage-induced senescence in the brain as a driver of neurodegeneration, with particular focus on breast cancer type 1, and its potential contribution to sex-specific differences associated with neurodegenerative disease.
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Affiliation(s)
- Emily Leung
- Department of Laboratory Medicine and Pathobiology, University of Toronto, 1 Kings College Cir, Toronto, ON M5S 1A8, Canada
- The Hospital for Sick Children, 555 University Ave, Toronto, ON M5G 1X8, Canada
| | - Lili-Naz Hazrati
- Department of Laboratory Medicine and Pathobiology, University of Toronto, 1 Kings College Cir, Toronto, ON M5S 1A8, Canada
- The Hospital for Sick Children, 555 University Ave, Toronto, ON M5G 1X8, Canada
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Schwab N, Ju Y, Hazrati LN. Early onset senescence and cognitive impairment in a murine model of repeated mTBI. Acta Neuropathol Commun 2021; 9:82. [PMID: 33964983 PMCID: PMC8106230 DOI: 10.1186/s40478-021-01190-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Accepted: 05/03/2021] [Indexed: 12/19/2022] Open
Abstract
Mild traumatic brain injury (mTBI) results in broad neurological symptoms and an increased risk of being diagnosed with a neurodegenerative disease later in life. While the immediate oxidative stress response and post-mortem pathology of the injured brain has been well studied, it remains unclear how early pathogenic changes may drive persistent symptoms and confer susceptibility to neurodegeneration. In this study we have used a mouse model of repeated mTBI (rmTBI) to identify early gene expression changes at 24 h or 7 days post-injury (7 dpi). At 24 h post-injury, gene expression of rmTBI mice shows activation of the DNA damage response (DDR) towards double strand DNA breaks, altered calcium and cell–cell signalling, and inhibition of cell death pathways. By 7 dpi, rmTBI mice had a gene expression signature consistent with induction of cellular senescence, activation of neurodegenerative processes, and inhibition of the DDR. At both timepoints gliosis, microgliosis, and axonal damage were evident in the absence of any gross lesion, and by 7 dpi rmTBI also mice had elevated levels of IL1β, p21, 53BP1, DNA2, and p53, supportive of DNA damage-induced cellular senescence. These gene expression changes reflect establishment of processes usually linked to brain aging and suggests that cellular senescence occurs early and most likely prior to the accumulation of toxic proteins. These molecular changes were accompanied by spatial learning and memory deficits in the Morris water maze. To conclude, we have identified DNA damage-induced cellular senescence as a repercussion of repeated mild traumatic brain injury which correlates with cognitive impairment. Pathways involved in senescence may represent viable treatment targets of post-concussive syndrome. Senescence has been proposed to promote neurodegeneration and appears as an effective target to prevent long-term complications of mTBI, such as chronic traumatic encephalopathy and other related neurodegenerative pathologies.
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Bachstetter AD, Garrett FG, Jicha GA, Nelson PT. Space-occupying brain lesions, trauma-related tau astrogliopathy, and ARTAG: a report of two cases and a literature review. Acta Neuropathol Commun 2021; 9:49. [PMID: 33757579 PMCID: PMC7986305 DOI: 10.1186/s40478-021-01152-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Accepted: 03/08/2021] [Indexed: 12/14/2022] Open
Abstract
Astrocytes with intracellular accumulations of misfolded phosphorylated tau protein have been observed in advanced-stage chronic traumatic encephalopathy (CTE) and in other neurodegenerative conditions. There is a growing awareness that astrocytic tau inclusions are also relatively common in the brains of persons over 70 years of age-affecting approximately one-third of autopsied individuals. The pathologic hallmarks of aging-related tau astrogliopathy (ARTAG) include phosphorylated tau protein within thorn-shaped astrocytes (TSA) in subpial, subependymal, perivascular, and white matter regions, whereas granular-fuzzy astrocytes are often seen in gray matter. CTE and ARTAG share molecular and histopathologic characteristics, suggesting that trauma-related mechanism(s) may predispose to the development of tau astrogliopathy. There are presently few experimental systems to study the pathobiology of astrocytic-tau aggregation, but human studies have made recent progress. For example, leucotomy (also referred to as lobotomy) is associated with a localized ARTAG-like neuropathology decades after the surgical brain injury, suggesting that chronic brain injury of any type may predispose to later life ARTAG. To examine this idea in a different context, we report clinical and pathologic features of two middle-aged men who came to autopsy with large (> 6 cm in greatest dimension) arachnoid cysts that had physically displaced and injured the subjects' left temporal lobes through chronic mechanical stress. Despite the similarity of the size and location of the arachnoid cysts, these individuals had dissimilar neurologic outcomes and neuropathologic findings. We review the evidence for ARTAG in response to brain injury, and discuss how the location and molecular properties of astroglial tau inclusions might alter the physiology of resident astrocytes. These cases and literature review point toward possible mechanism(s) of tau aggregation in astrocytes in response to chronic brain trauma.
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Affiliation(s)
- Adam D Bachstetter
- Spinal Cord and Brain Injury Research Center, University of Kentucky, 741 S. Limestone St., Lexington, KY, 40536, USA.
- Department of Neuroscience, University of Kentucky, Lexington, KY, USA.
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, USA.
| | - Filip G Garrett
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, USA
- Department of Pathology and Laboratory Medicine, University of Kentucky, Lexington, KY, USA
| | - Gregory A Jicha
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, USA
- Department of Neurology, University of Kentucky, Lexington, KY, USA
| | - Peter T Nelson
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, USA
- Department of Pathology and Laboratory Medicine, University of Kentucky, Lexington, KY, USA
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Lee KS, Lin S, Copland DA, Dick AD, Liu J. Cellular senescence in the aging retina and developments of senotherapies for age-related macular degeneration. J Neuroinflammation 2021; 18:32. [PMID: 33482879 PMCID: PMC7821689 DOI: 10.1186/s12974-021-02088-0] [Citation(s) in RCA: 67] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Accepted: 01/15/2021] [Indexed: 12/16/2022] Open
Abstract
Age-related macular degeneration (AMD), a degenerative disease in the central macula area of the neuroretina and the supporting retinal pigment epithelium, is the most common cause of vision loss in the elderly. Although advances have been made, treatment to prevent the progressive degeneration is lacking. Besides the association of innate immune pathway genes with AMD susceptibility, environmental stress- and cellular senescence-induced alterations in pathways such as metabolic functions and inflammatory responses are also implicated in the pathophysiology of AMD. Cellular senescence is an adaptive cell process in response to noxious stimuli in both mitotic and postmitotic cells, activated by tumor suppressor proteins and prosecuted via an inflammatory secretome. In addition to physiological roles in embryogenesis and tissue regeneration, cellular senescence is augmented with age and contributes to a variety of age-related chronic conditions. Accumulation of senescent cells accompanied by an impairment in the immune-mediated elimination mechanisms results in increased frequency of senescent cells, termed “chronic” senescence. Age-associated senescent cells exhibit abnormal metabolism, increased generation of reactive oxygen species, and a heightened senescence-associated secretory phenotype that nurture a proinflammatory milieu detrimental to neighboring cells. Senescent changes in various retinal and choroidal tissue cells including the retinal pigment epithelium, microglia, neurons, and endothelial cells, contemporaneous with systemic immune aging in both innate and adaptive cells, have emerged as important contributors to the onset and development of AMD. The repertoire of senotherapeutic strategies such as senolytics, senomorphics, cell cycle regulation, and restoring cell homeostasis targeted both at tissue and systemic levels is expanding with the potential to treat a spectrum of age-related diseases, including AMD.
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Affiliation(s)
- Keng Siang Lee
- Bristol Medical School, Translational Health Sciences, University of Bristol, Bristol, BS8 1TD, UK
| | - Shuxiao Lin
- School of Cellular and Molecular Medicine, University of Bristol, Bristol, BS8 1TD, UK
| | - David A Copland
- Bristol Medical School, Translational Health Sciences, University of Bristol, Bristol, BS8 1TD, UK
| | - Andrew D Dick
- Bristol Medical School, Translational Health Sciences, University of Bristol, Bristol, BS8 1TD, UK. .,Institute of Ophthalmology, University College London, London, EC1V 9EL, UK. .,National Institute for Health Research Biomedical Research Centre, Moorfields Eye Hospital, London, EC1V 2QH, UK.
| | - Jian Liu
- Bristol Medical School, Translational Health Sciences, University of Bristol, Bristol, BS8 1TD, UK.
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Davis CK, Vemuganti R. DNA damage and repair following traumatic brain injury. Neurobiol Dis 2020; 147:105143. [PMID: 33127471 DOI: 10.1016/j.nbd.2020.105143] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 10/09/2020] [Accepted: 10/23/2020] [Indexed: 01/05/2023] Open
Abstract
Traumatic brain injury (TBI) is known to promote significant DNA damage irrespective of age, sex, and species. Chemical as well as structural DNA modification start within minutes and persist for days after TBI. Although several DNA repair pathways are induced following TBI, the simultaneous downregulation of some of the genes and proteins of these pathways leads to an aberrant overall DNA repair process. In many instances, DNA damages escape even the most robust repair mechanisms, especially when the repair process becomes overwhelmed or becomes inefficient by severe or repeated injuries. The persisting DNA damage and/or lack of DNA repair contributes to long-term functional deficits. In this review, we discuss the mechanisms of TBI-induced DNA damage and repair. We further discussed the putative experimental therapies that target the members of the DNA repair process for improved outcome following TBI.
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Affiliation(s)
- Charles K Davis
- Department of Neurological Surgery, University of Wisconsin, Madison, WI, USA
| | - Raghu Vemuganti
- Department of Neurological Surgery, University of Wisconsin, Madison, WI, USA; William S. Middleton VA Hospital, Madison, WI, USA.
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Cacabelos R. Pharmacogenomics of Cognitive Dysfunction and Neuropsychiatric Disorders in Dementia. Int J Mol Sci 2020; 21:E3059. [PMID: 32357528 PMCID: PMC7246738 DOI: 10.3390/ijms21093059] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Revised: 04/21/2020] [Accepted: 04/21/2020] [Indexed: 02/07/2023] Open
Abstract
Symptomatic interventions for patients with dementia involve anti-dementia drugs to improve cognition, psychotropic drugs for the treatment of behavioral disorders (BDs), and different categories of drugs for concomitant disorders. Demented patients may take >6-10 drugs/day with the consequent risk for drug-drug interactions and adverse drug reactions (ADRs >80%) which accelerate cognitive decline. The pharmacoepigenetic machinery is integrated by pathogenic, mechanistic, metabolic, transporter, and pleiotropic genes redundantly and promiscuously regulated by epigenetic mechanisms. CYP2D6, CYP2C9, CYP2C19, and CYP3A4/5 geno-phenotypes are involved in the metabolism of over 90% of drugs currently used in patients with dementia, and only 20% of the population is an extensive metabolizer for this tetragenic cluster. ADRs associated with anti-dementia drugs, antipsychotics, antidepressants, anxiolytics, hypnotics, sedatives, and antiepileptic drugs can be minimized by means of pharmacogenetic screening prior to treatment. These drugs are substrates, inhibitors, or inducers of 58, 37, and 42 enzyme/protein gene products, respectively, and are transported by 40 different protein transporters. APOE is the reference gene in most pharmacogenetic studies. APOE-3 carriers are the best responders and APOE-4 carriers are the worst responders; likewise, CYP2D6-normal metabolizers are the best responders and CYP2D6-poor metabolizers are the worst responders. The incorporation of pharmacogenomic strategies for a personalized treatment in dementia is an effective option to optimize limited therapeutic resources and to reduce unwanted side-effects.
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Affiliation(s)
- Ramon Cacabelos
- EuroEspes Biomedical Research Center, International Center of Neuroscience and Genomic Medicine, 15165-Bergondo, Corunna, Spain
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