scholarly journals Radiation-induced brain injury: current concepts and therapeutic strategies targeting neuroinflammation

2020 ◽  
Vol 2 (1) ◽  
Author(s):  
Casmir Turnquist ◽  
Brent T Harris ◽  
Curtis C Harris
Keyword(s):  
Radiation Therapy ◽  
Brain Injury ◽  
Primary Treatment ◽  
Hippocampal Neurogenesis ◽  
Treatment Modalities ◽  
Cancer Therapies ◽  
Radiation Induced ◽  
Cancer Types

Abstract Continued improvements in cancer therapies have increased the number of long-term cancer survivors. Radiation therapy remains one of the primary treatment modalities with about 60% of newly diagnosed cancer patients receiving radiation during the course of their disease. While radiation therapy has dramatically improved patient survival in a number of cancer types, the late effects remain a significant factor affecting the quality of life particularly in pediatric patients. Radiation-induced brain injury can result in cognitive dysfunction, including hippocampal-related learning and memory dysfunction that can escalate to dementia. In this article, we review the current understanding of the mechanisms behind radiation-induced brain injury focusing on the role of neuroinflammation and reduced hippocampal neurogenesis. Approaches to prevent or ameliorate treatment-induced side effects are also discussed along with remaining challenges in the field.

Potential Role of Adult Hippocampal Neurogenesis in Traumatic Brain Injury

2021 ◽  
Vol 28 ◽  
Author(s):  
Lucas Alexandre Santos Marzano ◽  
Fabyolla Lúcia Macedo de Castro ◽  
Caroline Amaral Machado ◽  
João Luís Vieira Monteiro de Barros ◽  
Thiago Macedo e Cordeiro ◽  
...  
Keyword(s):  
Traumatic Brain Injury ◽  
Brain Injury ◽  
Clinical Studies ◽  
Molecular Mechanisms ◽  
Hippocampal Neurogenesis ◽  
Cognitive Outcomes ◽  
Adult Hippocampal Neurogenesis ◽  
The Brain

: Traumatic brain injury (TBI) is a serious cause of disability and death among young and adult individuals, displaying complex pathophysiology including cellular and molecular mechanisms that are not fully elucidated. Many experimental and clinical studies investigated the potential relationship between TBI and the process by which neurons are formed in the brain, known as neurogenesis. Currently, there are no available treatments for TBI’s long-term consequences being the search for novel therapeutic targets, a goal of highest scientific and clinical priority. Some studies evaluated the benefits of treatments aimed at improving neurogenesis in TBI. In this scenario, herein, we reviewed current pre-clinical studies that evaluated different approaches to improving neurogenesis after TBI while achieving better cognitive outcomes, which may consist in interesting approaches for future treatments.

scholarly journals Role of PPARs in Radiation-Induced Brain Injury

PPAR Research ◽  
2010 ◽  
Vol 2010 ◽  
pp. 1-12 ◽  
Author(s):  
Sriram Ramanan ◽  
Weiling Zhao ◽  
David R. Riddle ◽  
Mike E. Robbins
Keyword(s):  
Brain Injury ◽  
Inflammatory Responses ◽  
Current Knowledge ◽  
Whole Brain Irradiation ◽  
Brain Irradiation ◽  
Ppar Agonists ◽  
The Usa ◽  
Radiation Induced

Whole-brain irradiation (WBI) represents the primary mode of treatment for brain metastases; about 200 000 patients receive WBI each year in the USA. Up to 50% of adult and 100% of pediatric brain cancer patients who survive >6 months post-WBI will suffer from a progressive, cognitive impairment. At present, there are no proven long-term treatments or preventive strategies for this significant radiation-induced late effect. Recent studies suggest that the pathogenesis of radiation-induced brain injury involves WBI-mediated increases in oxidative stress and/or inflammatory responses in the brain. Therefore, anti-inflammatory strategies can be employed to modulate radiation-induced brain injury. Peroxisomal proliferator-activated receptors (PPARs) are ligand-activated transcription factors that belong to the steroid/thyroid hormone nuclear receptor superfamily. Although traditionally known to play a role in metabolism, increasing evidence suggests a role for PPARs in regulating the response to inflammation and oxidative injury. PPAR agonists have been shown to cross the blood-brain barrier and confer neuroprotection in animal models of CNS disorders such as stroke, multiple sclerosis and Parkinson's disease. However, the role of PPARs in radiation-induced brain injury is unclear. In this manuscript, we review the current knowledge and the emerging insights about the role of PPARs in modulating radiation-induced brain injury.

scholarly journals Nitric Oxide Regulates Neurogenesis in the Hippocampus following Seizures

2015 ◽  
Vol 2015 ◽  
pp. 1-14 ◽  
Author(s):  
Bruno P. Carreira ◽  
Daniela F. Santos ◽  
Ana I. Santos ◽  
Caetana M. Carvalho ◽  
Inês M. Araújo
Keyword(s):  
Nitric Oxide ◽  
Stem Cells ◽  
Brain Injury ◽  
Mouse Model ◽  
Hippocampal Neurogenesis ◽  
Nitrogen Species ◽  
Regulation Of Proliferation ◽  
Newborn Neurons

Hippocampal neurogenesis is changed by brain injury. When neuroinflammation accompanies injury, activation of resident microglial cells promotes the release of inflammatory cytokines and reactive oxygen/nitrogen species like nitric oxide (NO). In these conditions, NO promotes proliferation of neural stem cells (NSC) in the hippocampus. However, little is known about the role of NO in the survival and differentiation of newborn cells in the injured dentate gyrus. Here we investigated the role of NO following seizures in the regulation of proliferation, migration, differentiation, and survival of NSC in the hippocampus using the kainic acid (KA) induced seizure mouse model. We show that NO increased the proliferation of NSC and the number of neuroblasts following seizures but was detrimental to the survival of newborn neurons. NO was also required for the maintenance of long-term neuroinflammation. Taken together, our data show that NO positively contributes to the initial stages of neurogenesis following seizures but compromises survival of newborn neurons.

Histologic Findings of Choroidal Vasculopathy in Eyes Enucleated following Radiation Therapy for Uveal Melanoma: Radiation Choroidopathy

2021 ◽  
Author(s):  
Sean Platt ◽  
Diva R. Salomao ◽  
Jose Pulido
Keyword(s):  
Radiation Therapy ◽  
Uveal Melanoma ◽  
Malignant Tumors ◽  
Vitreous Hemorrhage ◽  
Radiation Retinopathy ◽  
Radiation Induced ◽  
Histopathologic Analysis ◽  
Choroidal Vessels ◽  
Choroidal Vasculopathy

Abstract Introduction Little has been published about the choroidal vascular changes that occur years after radiation exposure. The aim of this study was to review the histological changes observed in the choroidal vasculature following radiotherapy for uveal melanoma. Methods Records from a single institution were retrospectively reviewed from June 7, 2007 to June 7, 2017; 101 patients with a diagnosis of uveal melanoma that underwent enucleation had their records reviewed. Out of these, a total of 26 eyes had undergone plaque brachytherapy prior to enucleation, which had been performed at a mean time of 7.2 years (range from 0 years to 30 years) after the initial plaque placement. A histopathologic analysis was conducted on all 26 eyes with special emphasis on the choroidal changes. Of these 26 eyes, 18 demonstrated evidence of radiation-induced vasculopathy. Results Of the 18 eyes, 10/18 (55%) had radiation retinopathy and 16/18 (89%) had radiation choroidal vasculopathy. One patient had a phthisical eye, and the choroid could not be evaluated because the characteristics of the vasculature could not be determined. Nine cases had vitreous hemorrhage (50%), all cases had radiation retinopathy, and 8/9 (89%) had radiation choroidopathy. Of the 16 cases with radiation choroidal vasculopathy, 3/16 (19%) had only intratumoral radiation choroidal vasculopathy, 3/16 (19%) had only extratumoral radiation choroidal vasculopathy, and, thus, 10/16 (32%) had both intratumoral and extratumoral radiation choroidal vasculopathy. In patients with radiation choroidal vasculopathy, 2/16 (13%) had hyalinization of the choroidal vessels. Another 3/16 (19%) cases with radiation choroidal vasculopathy had ectatic vessels. The other 11/16 (68%) had evidence of both hyalinization of the choroidal vessels as well as ectatic vessels in the choroid. Histological evidence of radiation retinopathy and choroidopathy were seen in 69% of eyes enucleated after receiving radiation therapy, which, in some cases, also had vitreous hemorrhage. Polypoidal choroidal vasculopathy, choroidal neovascularization, and retinal choroidal anastomoses (RAP-type lesions) were seen in 12 of the 16 eyes (75%). Discussion/Conclusion Irradiation of malignant tumors of the eye causes not only radiation retinopathy but also radiation choroidopathy. The role of radiation choroidopathy in the subsequent visual loss following radiotherapy and the role of anti-VEGF therapy needs to be recognized and distinguished from radiation retinopathy. Our data adds to the prior limited knowledge that radiation affects the choroid and can induce specific phenotypes similar to the clinical spectrum of CNV, PCV, and RAP.

scholarly journals MBCL-14. A STUDY OF LOW-DOSE CRANIOSPINAL RADIATION THERAPY IN PATIENTS WITH NEWLY DIAGNOSED AVERAGE-RISK MEDULLOBLASTOMA

2020 ◽  
Vol 22 (Supplement_3) ◽  
pp. iii390-iii391
Author(s):  
Aaron Mochizuki ◽  
Anna Janss ◽  
Sonia Partap ◽  
Paul Fisher ◽  
Yimei Li ◽  
...  
Keyword(s):  
Overall Survival ◽  
Radiation Therapy ◽  
Treatment Modalities ◽  
Average Risk ◽  
Craniospinal Radiation ◽  
Grade 5 ◽  
Therapy Studies ◽  
Do So

Abstract INTRODUCTION Medulloblastoma is one of the most common malignant brain tumors in children. To date, the treatment of average-risk (non-metastatic, completely resected) medulloblastoma includes craniospinal radiation therapy and adjuvant chemotherapy. Modern treatment modalities and now risk stratification of subgroups have extended the survival of these patients, exposing the long-term morbidities associated with radiation therapy. METHODS We performed a single-arm, multi-institution study, seeking to reduce the late effects of treatment in patients with average-risk medulloblastoma prior to advances in molecular subgrouping. To do so, we reduced the dose of craniospinal irradiation by 25% to 18 gray with the goal of maintaining the therapeutic efficacy as described in CCG 9892 with maintenance chemotherapy. RESULTS 28 patients aged 3–30 years were enrolled across three institutions between April 2001 and December 2010. Median age at enrollment was 9 years with a median follow-up time of 11.7 years. The 3-year relapse-free (RFS) and overall survival (OS) were 78.6% (95% CI 58.4% to 89.8%) and 92.9% (95% CI 74.4% to 98.2%), respectively. The 5-year RFS and OS were 71.4% (95% CI 50.1% to 84.6%) and 85.7% (95% CI 66.3% to 94.4%), respectively. Toxicities were similar to those seen in other studies; there were no grade 5 toxicities. CONCLUSIONS Given the known neurocognitive adverse effects associated with cranial radiation therapy, studies to evaluate the feasibility of dose reduction are needed. In this study, we demonstrate that select patients with average-risk medulloblastoma may benefit from reduced craniospinal radiation dose of 18 gray without impacting relapse-free or overall survival.

scholarly journals Regulation of the p75 neurotrophin receptor attenuates neuroinflammation and stimulates hippocampal neurogenesis in experimental Streptococcus pneumoniae meningitis

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Dandan Zhang ◽  
Shengnan Zhao ◽  
Zhijie Zhang ◽  
Danfeng Xu ◽  
Di Lian ◽  
...  
Keyword(s):  
Transcription Factors ◽  
Streptococcus Pneumoniae ◽  
Proinflammatory Cytokines ◽  
Neuronal Apoptosis ◽  
Hippocampal Neurogenesis ◽  
Clinical Severity ◽  
Neurotrophin Receptor ◽  
Apoptosis And Necrosis

Abstract Background Streptococcus pneumoniae meningitis is a destructive central nervous system (CNS) infection with acute and long-term neurological disorders. Previous studies suggest that p75NTR signaling influences cell survival, apoptosis, and proliferation in brain-injured conditions. However, the role of p75NTR signaling in regulating pneumococcal meningitis (PM)-induced neuroinflammation and altered neurogenesis remains largely to be elucidated. Methods p75NTR signaling activation in the pathological process of PM was assessed. During acute PM, a small-molecule p75NTR modulator LM11A-31 or vehicle was intranasally administered for 3 days prior to S. pneumoniae exposure. At 24 h post-infection, clinical severity, histopathology, astrocytes/microglia activation, neuronal apoptosis and necrosis, inflammation-related transcription factors and proinflammatory cytokines/mediators were evaluated. Additionally, p75NTR was knocked down by the adenovirus-mediated short-hairpin RNA (shRNA) to ascertain the role of p75NTR in PM. During long-term PM, the intranasal administration of LM11A-31 or vehicle was continued for 7 days after successfully establishing the PM model. Dynamic changes in inflammation and hippocampal neurogenesis were assessed. Results Our results revealed that both 24 h (acute) and 7, 14, 28 day (long-term) groups of infected rats showed increased p75NTR expression in the brain. During acute PM, modulation of p75NTR through pretreatment of PM model with LM11A-31 significantly alleviated S. pneumoniae-induced clinical severity, histopathological injury and the activation of astrocytes and microglia. LM11A-31 pretreatment also significantly ameliorated neuronal apoptosis and necrosis. Moreover, we found that blocking p75NTR with LM11A-31 decreased the expression of inflammation-related transcription factors (NF-κBp65, C/EBPβ) and proinflammatory cytokines/mediators (IL-1β, TNF-α, IL-6 and iNOS). Furthermore, p75NTR knockdown induced significant changes in histopathology and inflammation-related transcription factors expression. Importantly, long-term LM11A-31 treatment accelerated the resolution of PM-induced inflammation and significantly improved hippocampal neurogenesis. Conclusion Our findings suggest that the p75NTR signaling plays an essential role in the pathogenesis of PM. Targeting p75NTR has beneficial effects on PM rats by alleviating neuroinflammation and promoting hippocampal neurogenesis. Thus, the p75NTR signaling may be a potential therapeutic target to improve the outcome of PM.

scholarly journals Regulation of the p75 Neurotrophin Receptor Attenuates Neuroinflammation and Stimulates Hippocampal Neurogenesis in Experimental Streptococcus Pneumoniae Meningitis

2021 ◽  
Author(s):  
Dandan Zhang ◽  
Shengnan Zhao ◽  
Zhijie Zhang ◽  
Danfeng Xu ◽  
Di Lian ◽  
...  
Keyword(s):  
Transcription Factors ◽  
Streptococcus Pneumoniae ◽  
Cell Apoptosis ◽  
Neuronal Cell ◽  
Hippocampal Neurogenesis ◽  
Clinical Severity ◽  
Neurotrophin Receptor ◽  
Double Labeling

Abstract Background: Streptococcus pneumoniae meningitis is a destructive central nervous system (CNS) infection with acute and long-term neurological disorders. Compelling evidence provided by previous studies suggests that p75NTR signaling influences cell survival, apoptosis, and proliferation in brain-injured conditions. However, the role of p75NTR signaling in regulating pneumococcal meningitis (PM)-induced neuroinflammation and altered neurogenesis remains largely to be elucidated.Methods: p75NTR signaling activation in the pathological process of PM was assessed. During acute PM, a small-molecule p75NTR modulator LM11A-31 or vehicle was intranasally administered for 3 days prior to S.pneumoniae exposure. At 24h post-infection, clinical severity, histopathology, astrocytes/microglia activation, neuronal cell apoptosis and death, inflammation-related transcription factors and inflammatory factors were evaluated. Additionally, p75NTR was knocked down by the adenovirus-mediated short-hairpin RNA (shRNA) to ascertain the role of p75NTR in PM. During long-term PM, the intranasal administration of LM11A-31 or vehicle was continued for 7 days after successfully establishing the PM model. Hippocampal neurogenesis was evaluated by double-labeling immunofluorescence with EdU, DCX and NeuN. Results: Our results revealed that both 24h (acute) and 7,14,28day (long-term) groups of infected rats demonstrated increased p75NTR expression in the brain. During acute PM, modulation of p75NTR through pretreatment of PM model with LM11A-31 significantly alleviated S.pneumoniae-induced clinical severity, histopathological injury and the activation of astrocytes and microglia. LM11A-31 pretreatment also significantly ameliorated neuronal cell apoptosis and death. Moreover, we found that blocking p75NTR with LM11A-31 decreased the expression of inflammation-related transcription factors (NF-κBp65, C/EBPβ) and proinflammatory cytokine (IL-1β, TNF-α, IL-6 and iNOS) in the cortex and hippocampus. Furthermore, p75NTR knockdown induced significant changes in histopathology and inflammation-related transcription factors expression. Importantly, combined LM11A-31 adjuvant therapy significantly improved hippocampal neurogenesis.Conclusion: Our findings suggest that the p75NTR signaling plays an essential role in the pathogenesis of PM. Targeting p75NTR has benefit effects on PM rats by alleviating neuroinflammation and promoting hippocampal neurogenesis. Thus, the p75NTR signaling may be a potential therapeutic target to improve the outcome of PM.

Sa2015 Traumatic Brain Injury and Intestinal Dysfunction: Investigating a Putative Role of the Brain-Gut Axis in Long-Term Consequences of Injury

2015 ◽  
Vol 148 (4) ◽  
pp. S-384
Author(s):  
Elise L. Ma ◽  
Allen Smith ◽  
Neemesh Desai ◽  
Alan Faden ◽  
Terez Shea-Donohue
Keyword(s):  
Traumatic Brain Injury ◽  
Brain Injury ◽  
Putative Role ◽  
Long Term Consequences ◽  
The Brain

The Things that Help, the Things that Get in the Way: Working Together to Improve Outcome Following Acquired Brain Injury

2018 ◽  
Vol 19 (3) ◽  
pp. 258-269 ◽  
Author(s):  
Jacinta M. Douglas
Keyword(s):  
Brain Injury ◽  
Acquired Brain Injury ◽  
Life Changes ◽  
Major Life ◽  
The Family ◽  
Working Together ◽  
The Impact ◽  
The Way

Working in neurological rehabilitation brings with it numerous opportunities to gain an understanding of the factors that contribute to shaping meaningful living and wellbeing for those tackling the major life changes encountered following acquired brain injury (ABI). These opportunities come in many forms: challenging and brave clients, wise and worrying families, questioning and inspiring colleagues, empowering and limiting work environments and rigid and advancing policy and legislative contexts.Our personal and collective understanding ofthe things that helpandthe things that get in the wayof effective rehabilitation continuously emerges from the convergence of the experience and knowledge afforded by these opportunities. The aim of this paper is to considerthe things that helpandthe things that get in the wayas they have been identified by people with ABI, their families and those who work with them and have been further evidenced through research targeted towards improving short, medium and long-term outcomes for those living with the consequences of ABI. Thesethingsas discussed in this paper capture the essential role of the self, the importance of rights and access to rehabilitation, the impact of the family and the contribution of social connection.

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