scholarly journals Functional role of brain-engrafted macrophages against brain injuries

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Xi Feng ◽  
Elma S. Frias ◽  
Maria S. Paladini ◽  
David Chen ◽  
Zoe Boosalis ◽  
...  

Abstract Background Brain-resident microglia have a distinct origin compared to macrophages in other organs. Under physiological conditions, microglia are maintained by self-renewal from the local pool, independent of hematopoietic progenitors. Pharmacological depletion of microglia during whole-brain radiotherapy prevents synaptic loss and long-term recognition memory deficits. However, the origin or repopulated cells and the mechanisms behind these protective effects are unknown. Methods CD45low/int/CD11b+ cells from naïve brains, irradiated brains, PLX5622-treated brains and PLX5622 + whole-brain radiotherapy-treated brains were FACS sorted and sequenced for transcriptomic comparisons. Bone marrow chimeras were used to trace the origin and long-term morphology of repopulated cells after PLX5622 and whole-brain radiotherapy. FACS analyses of intrinsic and exotic synaptic compartments were used to measure phagocytic activities of microglia and repopulated cells. In addition, concussive brain injuries were given to PLX5622 and brain-irradiated mice to study the potential protective functions of repopulated cells after PLX5622 + whole-brain radiotherapy. Results After a combination of whole-brain radiotherapy and microglia depletion, repopulated cells are brain-engrafted macrophages that originate from circulating monocytes. Comparisons of transcriptomes reveal that brain-engrafted macrophages have an intermediate phenotype that resembles both monocytes and embryonic microglia. In addition, brain-engrafted macrophages display reduced phagocytic activity for synaptic compartments compared to microglia from normal brains in response to a secondary concussive brain injury. Importantly, replacement of microglia by brain-engrafted macrophages spare mice from whole-brain radiotherapy-induced long-term cognitive deficits, and prevent concussive injury-induced memory loss. Conclusions Brain-engrafted macrophages prevent radiation- and concussion-induced brain injuries and cognitive deficits.

2021 ◽  
Vol In Press (In Press) ◽  
Author(s):  
Anya jafari ◽  
Zahra Siavashpour ◽  
Mohammad Houshyari

Context: Increased survival of patients with cancer raises the need to pay attention to long-term side effects. Patients with brain metastasis experienced cognition failure after whole-brain radiotherapy. This review aimed at concluding the efficacy of Memantine in preserving cognitive function by reducing the brain toxicity of whole-brain radiotherapy for metastatic brain cancers. Evidence Acquisition: Published studies evaluating memantine protective effects during brain metastasis radiotherapy were searched for in scientific databases (e.g., Embase, PubMed, Cochrane database, Google Scholar, Scopus) using keywords including whole-brain radiotherapy and Memantine. Results: A total of 4 prospective clinical trials were included in the review. Effects of Memantine on cognition tests were evaluated in these trials. A significantly better Hopkins Verbal Learning Test-Revised (HVLT-R) delayed recognition at months 6 was achieved in RTOG 0614 and NRG CC001. Longer time to cognitive decline was found in the memantine arm of the RTOG trial and was statistically significant. Memantine effects were not statistically significant before 2 months. Conclusions: It seems reasonable to consider Memantine during radiation to prevent long-term cognitive failure in patients with brain metastasis due to the current results. Memantine improves cognition function during whole-brain radiotherapy (WBRT) without adding irreparable complications.


2013 ◽  
Vol 31 (31) ◽  
pp. 3971-3979 ◽  
Author(s):  
Patrick G. Morris ◽  
Denise D. Correa ◽  
Joachim Yahalom ◽  
Jeffrey J. Raizer ◽  
David Schiff ◽  
...  

Purpose A multicenter phase II study was conducted to assess the efficacy of rituximab, methotrexate, procarbazine, and vincristine (R-MPV) followed by consolidation reduced-dose whole-brain radiotherapy (rdWBRT) and cytarabine in primary CNS lymphoma. Patients and Methods Patients received induction chemotherapy with R-MPV (five to seven cycles); those achieving a complete response (CR) received rdWBRT (23.4 Gy), and otherwise, standard WBRT was offered (45 Gy). Consolidation cytarabine was given after the radiotherapy. The primary end point was 2-year progression-free survival (PFS) in patients receiving rdWBRT. Exploratory end points included prospective neuropsychological evaluation, analysis of magnetic resonance imaging (MRI) white matter changes using the Fazekas scale, and evaluation of the apparent diffusion coefficient (ADC) as a prognostic factor. Results Fifty-two patients were enrolled, with median age of 60 years (range, 30 to 79 years) and median Karnofsky performance score of 70 (range, 50 to 100). Thirty-one patients (60%) achieved a CR after R-MPV and received rdWBRT. The 2-year PFS for this group was 77%; median PFS was 7.7 years. Median overall survival (OS) was not reached (median follow-up for survivors, 5.9 years); 3-year OS was 87%. The overall (N = 52) median PFS was 3.3 years, and median OS was 6.6 years. Cognitive assessment showed improvement in executive function (P < .01) and verbal memory (P < .05) after chemotherapy, and follow-up scores remained relatively stable across the various domains (n = 12). All examined MRIs (n = 28) displayed a Fazekas score of ≤ 3, and no patient developed scores of 4 to 5; differences in ADC values did not predict response (P = .15), PFS (P = .27), or OS (P = .33). Conclusion R-MPV combined with consolidation rdWBRT and cytarabine is associated with high response rates, long-term disease control, and minimal neurotoxicity.


2019 ◽  
Vol 5 (suppl) ◽  
pp. 124-124
Author(s):  
Buhai Wang ◽  
Shiwei Fu ◽  
Yuxiang Huang

124 Background: To investigate the preservation of long-term neurocognitive function in patients after hippocampal avoidance whole-brain radiotherapy (HA-WBRT). Methods: For the retrospective analysis, 50 patients diagnosed with brain metastases were selected and divided into two groups from 2015-01-01 to 2017-12-31 at the Department of Oncology, Jiangsu Subei People's Hospital. Group A (n=27) was hippocampal avoidance whole-brain radiotherapy group; group B (n=23) was whole brain radiation therapy (WBRT) group. Neurocognitive function was statistically analyzed at 3, 6, 9, 12, and 24 months after radiotherapy, as scored by the MMSE (Mine-Mental State Examination) scales and the MoCA (Montreal Cognitive Assessment) scales. The OS, PFS and tumor recurrence sites of the two groups was also analyzed. Results: After 12, 24 months after radiotherapy, there was a significant difference between the two groups. The cognitive function of the hippocampal protection group was significantly higher than that of the non-hippocampal protection group (P<0.05). There was no significant difference in OS (P=0.2) and PFS (P=0.18) between the two groups. 14 patents in group A and 12 patents in group B had brain tumor recurrence after radiation, only one patient in group A occurred 5 mm within the edge of the hippocampus (P>0.05). Conclusions: First, HA-WBRT has a protective effect on long-term neurocognitive function. Second, there was no statistically significant different on OS and PFS in patients who underwent HA-WBRT or WBRT. Third, HA-WBRT didn’t increase the risk of brain tumor recurrence within the edge of the hippocampus.


2006 ◽  
Vol 24 (28) ◽  
pp. 4570-4574 ◽  
Author(s):  
Igor T. Gavrilovic ◽  
Adília Hormigo ◽  
Joachim Yahalom ◽  
Lisa M. DeAngelis ◽  
Lauren E. Abrey

Purpose We previously reported a series of patients treated with high-dose methotrexate (MTX) -based chemotherapy, with or without whole brain radiotherapy. The purpose of this report is to update the initial results and provide long-term data regarding overall survival, patterns of relapse, and the risk of treatment-related neurotoxicity. Patients and Methods Fifty-seven patients with an average age of 65 and median Karnofsky performance score of 70 were treated; all patients have been observed longitudinally with serial magnetic resonance imaging scans and neurologic examinations. Results The overall median survival was 51 months with a median follow-up of 115 months for surviving patients. Twenty-five patients relapsed or developed progressive disease; median progression-free survival was 129 months. Seventeen patients developed treatment-related neurotoxicity; all but one had received whole brain radiotherapy as a component of treatment. Seventy-four percent of patients younger than 60 years who received both MTX-based chemotherapy and whole brain radiotherapy were alive at last follow-up. Median survival for patients older than 60 years was 29 months regardless of whether or not they received whole brain radiotherapy. Conclusion Long-term follow-up of our initial cohort confirms the observation of excellent overall survival, particularly for those patients younger than age 60 at diagnosis. For older patients, it appears to be reasonable to defer whole brain radiotherapy in an effort to minimize treatment-related neurotoxicity.


2019 ◽  
Vol 21 (Supplement_6) ◽  
pp. vi83-vi84
Author(s):  
Xi Feng ◽  
Sonali Gupta ◽  
David Chen ◽  
Zoe Boosalis ◽  
Sharon Liu ◽  
...  

Abstract Microglia have a distinct origin compared to blood circulating myeloid cells. Under normal physiological conditions, microglia are maintained by self-renewal, independent of hematopoietic progenitors. Following genetic or pharmacologic depletion, newborn microglia derive from the local residual pool and quickly repopulate the entire brain. The depletion of brain resident microglia during therapeutic whole-brain irradiation fully prevents irradiation-induced synaptic loss and recognition memory deficits but the mechanisms driving these protective effects are unknown. Here, we demonstrate that after CSF-1R inhibitor-mediated microglia depletion and therapeutic whole-brain irradiation, circulating monocytes engraft into the brain and replace the microglia pool. These monocyte-derived brain-engrafted macrophages have reduced phagocytic activity compared to microglia from irradiated brains, but similar to locally repopulated microglia without brain irradiation. Transcriptome comparisons reveal that brain-engrafted macrophages have both monocyte and embryonic microglia signatures. These results suggest that monocyte-derived brain-engrafted macrophages represent a novel therapeutic avenue for the treatment of brain radiotherapy-induced cognitive deficits.


2019 ◽  
Author(s):  
Xi Feng ◽  
David Chen ◽  
Sonali Gupta ◽  
Sharon Liu ◽  
Nalin Gupta ◽  
...  

AbstractResident microglia of the brain have a distinct origin compared to macrophages in other organs. Under physiological conditions, microglia are maintained by self-renewal from the local pool, independent of hematopoietic progenitors. Pharmacologic depletion of microglia during therapeutic whole-brain irradiation prevents synaptic loss and rescues recognition memory deficits but the mechanisms behind these protective effects are unknown. Here we demonstrate that after a combination of therapeutic whole-brain irradiation and microglia depletion, macrophages originating from circulating monocytes engraft into the brain and replace the microglia pool. Comparisons of transcriptomes reveal that brain-engrafted macrophages have an intermediate phenotype that resembles both monocytes and embryonic microglia. Importantly, the brain-engrafted macrophages have a reduced phagocytic activity for synaptic compartments compared to the activated microglia from irradiated brains, which in turn prevent the aberrant and chronic synapse loss that results in radiation-induced memory deficits. These results are the first to demonstrate that replacement of microglia by brain-engrafted macrophages represent a potential therapeutic avenue for the treatment of brain radiotherapy induced cognitive deficits.


2020 ◽  
pp. JCO.20.00747
Author(s):  
Nicolaus Andratschke ◽  
José Belderbos ◽  
Michael Mayinger ◽  
Sanne B. Schagen ◽  
Dirk De Ruysscher

2021 ◽  
Vol 20 ◽  
pp. 153303382110342
Author(s):  
Buhai Wang ◽  
Shiwei Fu ◽  
Yuxiang Huang ◽  
Liqin Liu ◽  
Yichen Liang ◽  
...  

Whole-brain radiotherapy (WBRT) is the mainstay of therapy in treating cancer patients with brain metastases, but unfortunately, it might also lead to decline in neurocognitive function. This study aims to investigate the preservation of long-term neurocognitive function in patients after hippocampal avoidance whole-brain radiotherapy (HA-WBRT). Retrospectively, 47 patients diagnosed with brain metastases of non-small cell lung cancer (NSCLC) between 2015-01-01 and 2017-12-31 at the Department of Oncology, XXX Hospital were selected and divided into 2 groups. Group A (n = 27) received HA-WBRT, whereas group B (n = 20) received WBRT. Neurocognitive function was analyzed at baseline and at 3, 6, 9, 12 and 24 months after radiotherapy, using Mine-Mental State Examination (MMSE) scales and Montreal Cognitive Assessment (MoCA) scales. The OS, PFS and tumor recurrence sites were also analyzed. When evaluated at 12 and 24 months after radiotherapy, the cognitive function scores of the hippocampal avoidance group were significantly higher than those of the non-hippocampal avoidance group ( P < 0.001). In terms of patient survival, there was no significant difference in OS ( P = 0.2) and PFS (P = 0.18) between these 2 groups. Fourteen patients in group A and 12 patients in group B had brain tumor recurrence after radiation, only one patient in group A occurred within 5 mm from the edge of the hippocampus ( P > 0.05). In conclusion, HA-WBRT might have a protective effect on long-term neurocognitive function and did not affect patient survival.


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