Chemotherapy-Induced Cognitive Impairment Is Associated with Cytokine Dysregulation and Disruptions in Neuroplasticity

Quercetin mitigates doxorubicin-induced neurodegenerative changes in the cerebral cortex and hippocampus of rats; insights to DNA damage, inflammation, synaptic plasticity

BACKGROUND

Doxorubicin (Dox) is one of the most effective anti-neoplastic agents. Quercetin (QE) exhibits antioxidant and anti-inflammatory properties.

AIM

To detect neuroprotective properties of quercetin in rats exposed to doxorubicin-induced brain injury.

MATERIAL AND METHODS

48 rats were allocated equally into four groups: control group: (given normal saline), QE group: (given 80 mg/kg of QE orally daily for 2 weeks), Dox group: (received 2.5 mg/kg of Dox every other day for a total of seven intraperitoneal injections), and Dox+QE group: (received 2.5 mg/kg of Dox every other day for a total of seven intraperitoneal injections and 80 mg/kg of QE orally daily for 2 weeks). Subsequently, biochemical analyses were carried out along with histopathological (light and electron microscopic) and immunohistochemical examinations of the cerebral cortex and hippocampus.

RESULTS

The Dox group revealed a decline in the activities of superoxide dismutase, catalase, and glutathione peroxidase, along with an increase in malondialdehyde and an increase in DNA damage. Furthermore, sections of the cerebral cortex and hippocampus revealed neurodegenerative changes, decreased synaptophysin, and increased Interleukin-1 beta expressions. Biochemical and histopathological results were markedly improved by QE administration.

CONCLUSIONS

It can be concluded that QE induces protective effects against Dox-induced neurotoxicity.

Nrf2 Signaling Pathway: a Potential Therapeutic Target in Combating Oxidative Stress and Neurotoxicity in Chemotherapy-Induced Cognitive Impairment

Chemotherapy-induced cognitive impairment (CICI) is one of the major adverse effects of antineoplastic drugs, which decrease the quality of life in cancer survivors. Extensive experimental and clinical research suggests that chemotherapeutic drugs generate an enormous amount of reactive oxygen species (ROS), contributing to oxidative stress, neuroinflammation, blood-brain barrier (BBB) disruption, and neuronal death, eventually leading to CICI. Despite the progress in exploring different pathological mechanisms of CICI, effective treatment to prevent CICI progression has not been developed yet. Nrf2 is the principal transcription factor that regulates cellular redox balance and inflammation-related gene expression. Emerging evidence suggests that upregulation of Nrf2 and its target genes could suppress oxidative stress, and neuroinflammation, restore BBB integrity, and increase neurogenesis. This review discusses the role of Nrf2 in CICI, how it responds to oxidative stress, inflammation, neurotoxicity, and potential Nrf2 activators that could be used to enhance Nrf2 activation in CICI.

Social enrichment alters the response of brain leukocytes to chemotherapy and tumor development in aged mice

Aging is a risk factor for the development of breast cancer. Foundational science studies have supported associations among neuroinflammation, breast cancer, and chemotherapy, but to date, these associations are based on studies using young adult rodents. The current study examined the neuroinflammatory effects of chemotherapy in aged, tumor-naïve and tumor-bearing mice with or without social enrichment. Mice received two intravenous injections of doxorubicin (A) and cyclophosphamide (C) at a two-week interval. Brain immune cells were enriched/assessed via flow cytometry, seven days following the second chemotherapy injection. Social enrichment enhanced peripheral immune cell trafficking in aged tumor-naive mice treated with AC. Group housed aged tumor bearing mice receiving AC had reduced percentage of IL-6+ monocytes and granulocytes relative to their singly housed counterparts. Notably, group housing aged experimental mice with young cage partners significantly reduced TNF + monocytes, tumor volume, and tumor mass. These data illustrate the importance of social enrichment in attenuating neuroinflammation and are the first to demonstrate that social support with young housing partners reduces tumor growth in aged mice.

The chemotherapeutic agent doxorubicin induces brain senescence, with modulation by APOE genotype

Many cancer patients experience serious cognitive problems related to their treatment, which can greatly affect their quality of life. The molecular mechanisms of this cancer chemotherapy-induced cognitive impairment (CICI) are unknown, thus slowing the development of preventative approaches. We hypothesized that cancer chemotherapies could induce cellular senescence in the brain, creating a pro-inflammatory environment and damaging normal brain communication. We tested this hypothesis using the common chemotherapeutic agent doxorubicin in two independent mouse models. In the first model, we used mice that express tdTomato under the pdkn2a (p16) promoter; p16 is a regulator of cellular senescence, and its upregulation is denoted by the presence of fluorescently tagged cells. Two weeks after exposure to three doses of 5 mg/kg doxorubicin, the number of tdTomato positive cells were increased nearly three-fold in both the cerebral cortex and the hippocampus. tdTomato staining co-localized with neurons, microglia, oligodendrocyte precursor cells, and endothelial cells, but not astrocytes. In the second model, we used APOE knock-in mice, since the APOE4 allele is a risk factor for CICI in humans and mouse models. We isolated RNA from the cerebral cortex of APOE3 and APOE4 mice from one to 21 days after a single dose of 10 mg/kg doxorubicin. Using NanoString analysis of over 700 genes related to neuroinflammation and RT-qPCR analysis of cerebral cortex transcripts, we found two-fold induction of four senescence-related genes at three weeks in the APOE4 mice compared to the APOE3 control mice: p21(cdkn1a), p16, Gadd45a, and Egr1. We conclude that doxorubicin promotes cellular senescence pathways in the brain, supporting the hypothesis that drugs to eliminate senescent cells could be useful in preventing CICI.

Stress-induced red nucleus attenuation induces anxiety-like behavior and lymph node CCL5 secretion

Previous studies have speculated that brain activity directly controls immune responses in lymphoid organs. However, the upstream brain regions that control lymphoid organs and how they interface with lymphoid organs to produce stress-induced anxiety-like behavior remain elusive. Using stressed human participants and rat models, we show that CCL5 levels are increased in stressed individuals compared to controls. Stress-inducible CCL5 is mainly produced from cervical lymph nodes (CLN). Retrograde tracing from CLN identifies glutamatergic neurons in the red nucleus (RN), the activities of which are tightly correlated with CCL5 levels and anxiety-like behavior in male rats. Ablation or chemogenetic inhibition of RN glutamatergic neurons increases anxiety levels and CCL5 expression in the serum and CLNs, whereas pharmacogenetic activation of these neurons reduces anxiety levels and CCL5 synthesis after restraint stress exposure. Chemogenetic inhibition of the projection from primary motor cortex to RN elicits anxiety-like behavior and CCL5 synthesis. This brain-lymph node axis provides insights into lymph node tissue as a stress-responsive endocrine organ.

L-carnitine Modulates Cognitive Impairment Induced by Doxorubicin and Cyclophosphamide in Rats; Insights to Oxidative Stress, Inflammation, Synaptic Plasticity, Liver/brain, and Kidney/brain Axes

Chemotherapy-induced cognitive impairment in cancer patients is known as "chemobrain". Doxorubicin and Cyclophosphamide are two chemotherapeutic agents used in combination to treat solid tumors. L-carnitine was reported for its anti-oxidant and anti-inflammatory activities. The goal of the present study was to elucidate the neuroprotective effect of L-carnitine against chemobrain induced by Doxorubicin and Cyclophosphamide in rats. Rats were divided into five groups: Control group; Doxorubicin (4mg/kg, IV) and Cyclophosphamide (40mg/kg, IV)-treated group; two L-carnitine-treated groups (150 and 300mg/kg, ip) with Doxorubicin and Cyclophosphamide; and L-carnitine alone-treated group (300mg/kg). Doxorubicin and Cyclophosphamide induced histopathological changes in rats' hippocampi and prefrontal cortices, as well as reduced memory as evidenced by behavioural testing. L-carnitine treatment showed opposite effects. In addition, chemotherapy treatment enhanced oxidative stress via reducing catalase and glutathione levels, and inducing lipid peroxidation. By contrast, L-carnitine treatment showed powerful antioxidant effects reversing chemotherapy-induced oxidative damage. Moreover, chemotherapy combination induced inflammation via their effect on nuclear factor kappa B (p65), interleukin-1β, and tumor necrosis factor-α. However, L-carnitine treatment corrected such inflammatory responses. Furthermore, Doxorubicin and Cyclophosphamide reduced synaptic plasticity via hindering expression of brain-derived neurotrophic factor, phosphorylated cyclase response element binding protein, synaptophysin, and postsynaptic density protein 95 whereas protein expression of such synaptic plasticity biomarkers was enhanced by L-carnitine treatment. Finally, acetylcholinesterase activity was found to be enhanced by chemotherapy treatment affecting rats' memory while L-carnitine treatment reduced acetylcholinesterase activity. L-carnitine also showed hepatoprotective and renal protective effects suggesting liver/brain and kidney/brain axes as possible mechanisms for its neuroprotective effects.

Chemotherapy-Mediated Neuronal Aberration

Chemotherapy is a life-sustaining therapeutic option for cancer patients. Despite the advancement of several modern therapies, such as immunotherapy, gene therapy, etc., chemotherapy remains the first-line therapy for most cancer patients. Along with its anti-cancerous effect, chemotherapy exhibits several detrimental consequences that restrict its efficacy and long-term utilization. Moreover, it effectively hampers the quality of life of cancer patients. Cancer patients receiving chemotherapeutic drugs suffer from neurological dysfunction, referred to as chemobrain, that includes cognitive and memory dysfunction and deficits in learning, reasoning, and concentration ability. Chemotherapy exhibits neurotoxicity by damaging the DNA in neurons by interfering with the DNA repair system and antioxidant machinery. In addition, chemotherapy also provokes inflammation by inducing the release of various pro-inflammatory cytokines, including NF-kB, IL-1β, IL-6, and TNF-α. The chemotherapy-mediated inflammation contributes to chemobrain in cancer patients. These inflammatory cytokines modulate several growth signaling pathways and reactive oxygen species homeostasis leading to systemic inflammation in the body. This review is an effort to summarize the available information which discusses the role of chemotherapy-induced inflammation in chemobrain and how it impacts different aspects of therapeutic outcome and the overall quality of life of the patient. Further, this article also discusses the potential of herbal-based remedies to overcome chemotherapy-mediated neuronal toxicity as well as to improve the quality of life of cancer patients.

Inhibition of Fatty Acid Amide Hydrolase (FAAH) Regulates NF-kb Pathways Reducing Bleomycin-Induced Chronic Lung Inflammation and Pulmonary Fibrosis

The deadly interstitial lung condition known as idiopathic pulmonary fibrosis (IPF) worsens over time and for no apparent reason. The traditional therapy approaches for IPF, which include corticosteroids and immunomodulatory drugs, are often ineffective and can have noticeable side effects. The endocannabinoids are hydrolyzed by a membrane protein called fatty acid amide hydrolase (FAAH). Increasing endogenous levels of endocannabinoid by pharmacologically inhibiting FAAH results in numerous analgesic advantages in a variety of experimental models for pre-clinical pain and inflammation. In our study, we mimicked IPF by administering intratracheal bleomycin, and we administered oral URB878 at a dose of 5 mg/kg. The histological changes, cell infiltration, pro-inflammatory cytokine production, inflammation, and nitrosative stress caused by bleomycin were all reduced by URB878. Our data clearly demonstrate for the first time that the inhibition of FAAH activity was able to counteract not only the histological alteration bleomycin-induced but also the cascade of related inflammatory events.

An update on neurobiological mechanisms involved in the development of chemotherapy-induced cognitive impairment (CICI)

Cancer is the second leading cause of death worldwide despite efforts in early diagnosis of the disease and advances in treatment. The use of drugs that exert toxic effects on tumor cells or chemotherapy is one of the most widely used treatments against cancer. However, its low toxic selectivity affects both healthy cells and cancer cells. It has been reported that chemotherapeutic drugs may generate neurotoxicity that induces deleterious effects of chemotherapy in the central nervous system. In this sense, patients report decreased cognitive abilities, such as memory, learning, and some executive functions after chemotherapy. This chemotherapy-induced cognitive impairment (CICI) develops during treatment and persists even after chemotherapy. Here we present a review of the literature on the main neurobiological mechanisms involved in CICI using a Boolean formula following the steps of the PRISMA guidelines that were used to perform statements searches in various databases. The main mechanisms described in the literature to explain CRCI include direct and indirect mechanisms that induce neurotoxicity by chemotherapeutic agents. Therefore, this review provides a general understanding of the neurobiological mechanisms of CICI and the possible therapeutic targets to prevent it..

Cognitive impairment after cancer treatment: mechanisms, clinical characterization, and management

Cognitive impairment is a debilitating side effect experienced by patients with cancer treated with systemically administered anticancer therapies. With around 19.3 million new cases of cancer worldwide in 2020 and the five year survival rate growing from 50% in 1970 to 67% in 2013, an urgent need exists to understand enduring side effects with severe implications for quality of life. Whereas cognitive impairment associated with chemotherapy is recognized in patients with breast cancer, researchers have started to identify cognitive impairment associated with other treatments such as immune, endocrine, and targeted therapies only recently. The underlying mechanisms are diverse and therapy specific, so further evaluation is needed to develop effective therapeutic interventions. Drug and non-drug management strategies are emerging that target mechanistic pathways or the cognitive deficits themselves, but they need to be rigorously evaluated. Clinically, consistent use of objective diagnostic tools is necessary for accurate diagnosis and clinical characterization of cognitive impairment in patients treated with anticancer therapies. This should be supplemented with clinical guidelines that could be implemented in daily practice. This review summarizes the recent advances in the mechanisms, clinical characterization, and novel management strategies of cognitive impairment associated with treatment of non-central nervous system cancers.

The effectiveness of anti-inflammatory agents in reducing chemotherapy-induced cognitive impairment in preclinical models - A systematic review

Chemotherapy-induced cognitive impairment (CICI) is a debilitating condition resulting from chemotherapy administration for cancer treatment. CICI is characterised by various cognitive impairments, including issues with learning, memory, and concentration, impacting quality of life. Several neural mechanisms are proposed to drive CICI, including inflammation, therefore, anti-inflammatory agents could ameliorate such impairments. Research is still in the preclinical stage; however, the efficacy of anti-inflammatories to reduce CICI in animal models is unknown. Therefore, a systematic review was conducted, with searches performed in PubMed, Scopus, Embase, PsycInfo and Cochrane Library. A total of 64 studies were included, and of the 50 agents identified, 41 (82%) reduced CICI. Interestingly, while non-traditional anti-inflammatory agents and natural compounds reduced impairment, the traditional agents were unsuccessful. Such results must be taken with caution due to the heterogeneity observed in terms of methods employed. Nevertheless, preliminary evidence suggests anti-inflammatory agents could be beneficial for treating CICI, although it may be critical to think beyond the use of traditional anti-inflammatories when considering which specific compounds to prioritise in development.

Neurons as stromal drivers of nervous system cancer formation and progression

Similar to their pivotal roles in nervous system development, neurons have emerged as critical regulators of cancer initiation, maintenance, and progression. Focusing on nervous system tumors, we describe the normal relationships between neurons and other cell types relevant to normal nerve function, and discuss how disruptions of these interactions promote tumor evolution, focusing on electrical (gap junctions) and chemical (synaptic) coupling, as well as the establishment of new paracrine relationships. We also review how neuron-tumor communication contributes to some of the complications of cancer, including neuropathy, chemobrain, seizures, and pain. Finally, we consider the implications of cancer neuroscience in establishing risk for tumor penetrance and in the design of future anti-tumoral treatments.

Functional changes of the prefrontal cortex, insula, caudate and associated cognitive impairment (chemobrain) in NSCLC patients receiving different chemotherapy regimen

INTRODUCTION

Chemotherapy-induced cognitive impairment (CICI), termed "chemobrain", is highly prevalent in cancer patients following the administration of chemotherapeutic agents. However, the potential pathophysiological mechanisms underlying CICI remain unknown. This study aimed to explore the functional changes of the brain and associated cognitive impairment in non-small cell lung cancer (NSCLC) patients receiving different chemotherapy regimen.

METHODS

A total of 49 NSCLC patients (25 patients receiving pemetrexed plus carboplatin chemotherapy (PeCC) and 24 patients receiving paclitaxel plus carboplatin chemotherapy (PaCC)) and 61 healthy controls (HCs) were recruited and underwent resting-state functional magnetic resonance imaging (rs-fMRI) scanning, as well as cognitive function tests including Mini Mental State Exam (MMSE), Montreal Cognitive Assessment (MoCA), Functional Assessment of Cancer Therapy-Cognitive Function (FACT-Cog). Brain functional activities were measured by regional homogeneity (ReHo) values, which were calculated and compared between groups. In addition, the associations between ReHo values of changed brain regions and scores of cognitive scales were evaluated.

RESULTS

NSCLC patients showed decreased scores of MMSE, MoCA and FACT-Cog and decreased ReHo values in the bilateral superior frontal gyrus (medial), middle frontal gyrus, left inferior frontal gyrus (orbital part) and increased ReHo values in the bilateral insula and caudate. Compared with HCs, patients receiving PeCC demonstrated decreased ReHo values in the right superior frontal gyrus (dorsolateral), left superior frontal gyrus (medial orbital), middle frontal gyrus, insula and rectus gyrus while patients receiving PaCC presented increased ReHo values in the right rolandic operculum, left insula and right caudate. Compared with patients receiving PaCC, patients receiving PeCC had decreased ReHo values in the left superior frontal gyrus (orbital part), middle frontal gyrus and increased ReHo values in the left inferior temporal gyrus, lingual gyrus. Moreover, positive relationships were found between ReHo values of the left and right superior frontal gyrus (medial) and the total scores of FACT-Cog in the patient group.

CONCLUSION

The findings provided evidences that carboplatin-based chemotherapy could cause CICI accompanied by functional changes in the prefrontal cortex, insula, caudate. These might be the pathophysiological basis for CICI of NSCLC patients and were affected by the differences of chemotherapeutic agent administration through different biological mechanisms.

Mechanisms of Chemotherapy-Induced Neurotoxicity

Since the first clinical trials conducted after World War II, chemotherapeutic drugs have been extensively used in the clinic as the main cancer treatment either alone or as an adjuvant therapy before and after surgery. Although the use of chemotherapeutic drugs improved the survival of cancer patients, these drugs are notorious for causing many severe side effects that significantly reduce the efficacy of anti-cancer treatment and patients’ quality of life. Many widely used chemotherapy drugs including platinum-based agents, taxanes, vinca alkaloids, proteasome inhibitors, and thalidomide analogs may cause direct and indirect neurotoxicity. In this review we discuss the main effects of chemotherapy on the peripheral and central nervous systems, including neuropathic pain, chemobrain, enteric neuropathy, as well as nausea and emesis. Understanding mechanisms involved in chemotherapy-induced neurotoxicity is crucial for the development of drugs that can protect the nervous system, reduce symptoms experienced by millions of patients, and improve the outcome of the treatment and patients’ quality of life.

Fatty Acid Amide Hydrolase (FAAH) Inhibition Plays a Key Role in Counteracting Acute Lung Injury

Acute lung injury (ALI) is a group of lung illnesses characterized by severe inflammation, with no treatment. The fatty acid amide hydrolase (FAAH) enzyme is an integral membrane protein responsible for the hydrolysis of the main endocannabinoids, such as anandamide (AEA). In pre-clinical pain and inflammation models, increasing the endogenous levels of AEA and other bioactive fatty acid amides (FAAs) via genetic deletion or the pharmacological inhibition of FAAH produces many analgesic benefits in several different experimental models. To date, nobody has investigated the role of FAAH inhibition on an ALI mouse model. Mice were subjected to a carrageenan injection and treated orally 1 h after with the FAAH inhibitor URB878 dissolved in a vehicle consisting of 10% PEG-400, 10% Tween-80 and 80% saline at different doses: The inhibition of FAAH activity was able to counteract not only the CAR-induced histological alteration, but also the cascade of related inflammatory events. URB878 clears the way for further studies based on FAAH inhibition in acute lung pathologies.

Piperlongumine as a Neuro-Protectant in Chemotherapy Induced Cognitive Impairment

Advances in the early diagnosis and treatment have led to increases in breast cancer survivorship. Survivors report cognitive impairment symptoms such as loss of concentration and learning and memory deficits which significantly reduce the patient's quality of life. Additional therapies are needed to prevent these side effects and, the precise mechanisms of action responsible are not fully elucidated. However, increasing evidence points toward the use of neuroprotective compounds with antioxidants and anti-inflammatory properties as tools for conserving learning and memory. Here, we examine the ability of piperlongumine (PL), an alkaloid known to have anti-inflammatory and antioxidant effects, to play a neuroprotective role in 16-week-old female C57BL/6J mice treated with a common breast cancer regimen of doxorubicin, cyclophosphamide, and docetaxel (TAC). During social memory testing, TAC-treated mice exhibited impairment, while TAC/PL co-treated mice did not exhibit measurable social memory deficits. Proteomics analysis showed ERK1/2 signaling is involved in TAC and TAC/PL co-treatment. Reduced Nrf2 mRNA expression was also observed. mRNA levels of Gria2 were increased in TAC treated mice and reduced in TAC/PL co-treated mice. In this study, PL protects against social memory impairment when co-administered with TAC via multifactorial mechanisms involving oxidative stress and synaptic plasticity.

Clemastine Rescues Chemotherapy-Induced Cognitive Impairment by Improving White Matter Integrity

With the improvement of cancer treatment techniques, increasing attention has been given to chemotherapy-induced cognitive impairment through white matter injury. Clemastine fumarate has been shown to enhance white matter integrity in cuprizone- or hypoxia-induced demyelination mouse models. However, whether clemastine can be beneficial for reversing chemotherapy-induced cognitive impairment remains unexplored. In this study, the mice received oral administration of clemastine after chemotherapy. The open-field test and Morris water maze test were used to evaluate their anxiety, locomotor activity and cognitive function. Luxol Fast Blue staining and transmission electron microscopy were used to detect the morphological damage to the myelin. Demyelination and damage to the mature oligodendrocytes and axons were observed by immunofluorescence and western blotting. Clemastine significantly improved their cognitive function and ameliorated white matter injury in the chemotherapy-treated mice. Clemastine enhanced myelination, promoted oligodendrocyte precursor cell differentiation and increased the neurofilament 200 protein levels in the corpus callosum and hippocampus. We concluded that clemastine rescues cognitive function damage caused by chemotherapy through improving white matter integrity. Remyelination, oligodendrocyte differentiation and the increase of neurofilament protein promoted by clemastine are potential strategies for reversing the cognitive dysfunction caused by chemotherapy.

Behavioral and morphological effects of resveratrol and curcumin in rats submitted to doxorubicin-induced cognitive impairment

Doxorubicin (DOX) is known to cause cognitive impairments in patients submitted to long-term chemotherapy (deficits also known as chemobrain). Therefore, there is an urgent need for therapeutic strategies capable of returning cancer survivors back to their previous quality of life. The present study investigated whether resveratrol (RSV) or curcumin (CUR) administration could affect mnemonic function and brain morphological changes following DOX administration in rats. Male Wistar rats were divided into 4 groups: DOX group (2.5 mg/kg/week for 4 weeks, i.p., plus distilled water for 28 days, oral gavage - OG), DOX + RSV group (DOX, 2.5 mg/kg/week for 4 weeks, i.p., plus RSV, 10 mg/kg/day for 28 days, OG), DOX + CUR group (DOX, 2.5 mg/kg/week for 4 weeks, i.p., plus CUR, 100 mg/kg/day for 28 days, OG) and control (CTR) group (0.9% saline solution weekly for 4 weeks, i.p., plus distilled water for 28 days, OG). Behavioral analyses (open field - OF - and the novel object recognition test - NORT) were performed. Brains were collected and analyzed by hematoxylin-eosin and luxol fast blue staining techniques and by immunohistochemistry for GFAP (glial fibrillary acidic protein) expression in astrocytes and Iba1 (ionized calcium-binding adaptor molecule 1) expression in microglia. DOX-injected rats presented short-term and long-term memory impairments as seen in the NORT at 3 and 24 h after habituation and increased GFAP and Iba1 expression, respectively, in astrocytes and microglia of the frontal cortex, hypothalamus and hippocampus. Such cognitive deficits were prevented by CUR at both periods and by RSV at 24 h. DOX-induced astrogliosis and microgliosis were avoided by RSV and CUR. No signs of demyelination or neuronal loss were found in any group. Thus, CUR and RSV prevented memory loss, astrogliosis and microgliosis induced by DOX monotherapy.

Structural and Functional Brain Imaging in Long-Term Survivors of Childhood Acute Lymphoblastic Leukemia Treated With Chemotherapy: A Systematic Review

Background

The effect of chemotherapy on brain development in long-term survivors of pediatric acute lymphoblastic leukemia (ALL) was systematically reviewed.

Methods

A systematic search of Pubmed, Scopus, and PsycINFO databases was conducted to identify articles published between January 2000 and February 2020 that implemented magnetic resonance imaging to assess brain structure and function in pediatric ALL survivors (diagnosed younger than 21 years of age). The review included articles that were published on children diagnosed with ALL between 0 and 21 years of age and treated with chemotherapy-only protocols. Articles meeting the inclusion criteria described survivors on average of 5 years or more from diagnosis and were peer-reviewed articles and original studies.

Results

The search yielded 1975 articles with 23 articles meeting inclusion criteria. The review revealed that survivors had statistically significant alterations in brain anatomy, most commonly a smaller hippocampus and impaired microstructural white matter integrity in frontal brain regions. Survivors also had impaired brain function including lower brain network efficiency and altered resting state connectivity. Survivors also displayed widespread reductions in brain activation (ie, frontal, temporal, parietal brain regions) during cognitive tasks.

Conclusion

Although the neurotoxic effects of cancer treatment are reduced in the absence of cranial radiation, survivors treated on chemotherapy-only protocols still display long-term alterations in brain structure and function, which contribute to lifelong neurocognitive late effects.

Atrazine Inhalation Causes Neuroinflammation, Apoptosis and Accelerating Brain Aging

BACKGROUND

exposure to environmental contaminants has been linked to an increased risk of neurological diseases and poor outcomes. Chemical name of Atrazine (ATR) is 6-chloro-N-ethyl-N'-(1-methylethyl)-1,3,5-triazine-2,4-diamine, and it is the most commonly used broad-spectrum herbicide in agricultural crops. Several studies have demonstrated that ATR has the potential to be harmful to the brain's neuronal circuits. Until today nobody has explored the effect of ATR inhalation on young and aged mice.

METHODS

young and aged mice were subject to 25 mg of ATR in a vehicle made with saline and 10% of Dimethyl sulfoxide (DMSO) every day for 28 days. At the end of experiment different behavioral test were made and brain was collected.

RESULTS

exposure to ATR induced the same response in terms of behavioral alterations and motor and memory impairment in mice but in aged group was more marked. Additionally, in both young and aged mice ATR inhalations induced oxidative stress with impairment in physiological antioxidant response, lipid peroxidation, nuclear factor kappa-light-chain-enhancer of activated B cells (nf-κb) pathways activation with consequences of pro-inflammatory cytokines release and apoptosis. However, the older group was shown to be more sensitive to ATR inhalation.

CONCLUSIONS

our results showed that aged mice were more susceptible compared to young mice to air pollutants exposure, put in place a minor physiologically response was seen when exposed to it.

An Overview on Chemotherapy-induced Cognitive Impairment and Potential Role of Antidepressants

BACKGROUND

Cognitive impairment is an adverse reaction of cancer chemotherapy and is likely to affect up to 75% of patients during the treatment and 35% of patients experience it for several months after the chemotherapy. Patients manifest symptoms like alteration in working ability, awareness, concentration, visual-verbal memory, attention, executive functions, processing speed, fatigue and behavioural dysfunctions. Post-chemotherapy, cancer survivors have a reduced quality of life due to the symptoms of chemobrain. Apart from this, there are clinical reports which also associate mood disorders, vascular complications, and seizures in some cases. Therefore, the quality of lifestyle of cancer patients/ survivors is severely affected and only worsens due to the absence of any efficacious treatments. With the increase in survivorship, it's vital to identify effective strategies, until then only symptomatic relief for chemobrain can be provided. The depressive symptoms were causally linked to the pathophysiological imbalance between the pro and antiinflammatory cytokines.

CONCLUSION

The common causative factor, cytokines can be targeted for the amelioration of an associated symptom of both depression and chemotherapy. Thus, antidepressants can have a beneficial effect on chemotherapy-induced inflammation and cognitive dysfunction via cytokine balance. Also, neurogenesis property of certain antidepressant drugs rationalises their evaluation against CICI. This review briefly glances upon chemotherapy-induced cognitive impairment (CICI), and the modulatory effect of antidepressants on CICI pathomechanisms.

Microglia in Cancer Therapy-Related Cognitive Impairment

Millions of cancer survivors experience a persistent neurological syndrome that includes deficits in memory, attention, information processing, and mental health. Cancer therapy-related cognitive impairment can cause mild to severe disruptions to quality of life for these cancer survivors. Understanding the cellular and molecular underpinnings of this disorder will facilitate new therapeutic strategies aimed at ameliorating these long-lasting impairments. Accumulating evidence suggests that a range of cancer therapies induce persistent activation of the brain's resident immune cells, microglia. Cancer therapy-induced microglial activation disrupts numerous mechanisms of neuroplasticity, and emerging findings suggest that this impairment in plasticity is central to cancer therapy-related cognitive impairment. This review explores reactive microglial dysregulation of neural circuit structure and function following cancer therapy.

Relationship between cytokines and brain-derived neurotrophic factor (BDNF) in trajectories of cancer-related cognitive impairment

Cytokines facilitate the peripheral immune and cerebral response, through their ability to modulate the expression of brain derived neurotrophic factor (BDNF). Cytokines and BDNF are implicated in cancer-related cognitive impairment (CRCI), but their relationship has not been clearly defined for this condition. The aim of this study was to evaluate the associations of cytokines and BDNF among early stage breast cancer (ESBC) patients with different CRCI trajectories. This was a multicenter longitudinal study involving 136 ESBC patients. CRCI was assessed using the FACT-Cog (V3) questionnaire. Plasma cytokines and BDNF levels were quantified at three time points throughout chemotherapy. The associations between cytokines and BDNF were analyzed using linear mixed models, with interaction terms for CRCI status. All cytokines analyzed showed inverse associations with BDNF levels. There was a significant interaction between IL-6 and the persistent impairment trajectory, which would impact on BDNF levels (p = 0.026). The inverse associations with BDNF were more pronounced for IFN-γ, IL-1β, IL-4, IL-8, and GM-CSF in patients with persistent CRCI. The coefficient values for IL-2, IL-4, and TNF-α also indicate that there was a greater magnitude of decrease in BDNF level for every unit of cytokine increase in patients with acute and persistent CRCI, compared to patients without CRCI. The differential associations between cytokines and BDNF may be indicative of probable susceptibility to the elevation of cytokines. Further research is required to elucidate the specific associations of cytokines and BDNF, along with their contributions to acute and persistent CRCI.

Neuroimmune reactivity marker expression in rodent models of chemotherapy-induced cognitive impairment: A systematic scoping review

BACKGROUND

Chemotherapy-induced cognitive impairment (CICI) is a debilitating side effect arising from chemotherapy treatments. The condition is characterised by a range of cognitive deficits including impairment to memory, attention, and concentration. Whilst the underlying mechanisms that contribute to CICI remain unclear, neuroinflammation has been suggested as one key contributor.

METHOD

A comprehensive systematic search of EMBASE and Medline via PubMed was conducted to identify studies on neuroimmune reactivity marker expression changes and resulting cognitive changes in preclinical rodent models of CICI.

RESULTS

A total of twenty studies met the eligibility criteria and were included in the scoping review. There was significant heterogeneity in the methodology employed in the included studies. Our findings demonstrate that widespread changes in cytokines, chemokines, microglia reactivity, and astrocyte reactivity are observed in CICI in the brain regions expected to be affected, given the nature of the cognitive impairment observed in CICI.

CONCLUSIONS

Although there was considerable heterogeneity in study design that made comparisons between studies difficult, our findings suggest that neuroinflammation commonly occurs in CICI preclinical rodent models and shows an association with cognitive impairment.

Cognitive impairment resulting from treatment with docetaxel, doxorubicin, and cyclophosphamide

Breast cancer is the most commonly diagnosed cancer among women and it is estimated that about 30% of newly diagnosed cancers in women will be breast cancers. While advancements in treating breast cancer have led to an average 5-year survival rate of 90%, many survivors experience cognitive impairments as a result of chemotherapy treatment. Doxorubicin, cyclophosphamide, and docetaxel (TAC) are commonly administered as breast cancer treatments; however, there are few studies that have tested the cognitive effects of TAC. In the current study, 12-week-old female C57BL/6 mice received 4 weekly intraperitoneal injections of either saline or a combination therapy of doxorubicin and cyclophosphamide followed by 4 weekly docetaxel injections. Four weeks after the last injection, mice were tested for hippocampus-dependent cognitive performance in the Y-maze and the Morris water maze. During Y-maze testing, mice exposed to TAC exhibited impairment. During the water maze assessment, all animals were able to locate the visible and hidden platform locations. However, mice that received the TAC presented with a significant impairment in spatial memory retention on the probe trial days. TAC treatment significantly decreases the dendritic complexity of arborization in the dentate gyrus region of the hippocampus. In addition, comparative proteomic analysis revealed downregulation of proteins within key metabolic and signaling pathways associated with cognitive dysfunction, such as oxidative phosphorylation, ephrin signaling, and calcium signaling.

Cancer Chemotherapy Related Cognitive Impairment and the Impact of the Alzheimer's Disease Risk Factor APOE

Cancer related cognitive impairment (CRCI) is a serious impairment to maintaining quality of life in cancer survivors. Cancer chemotherapy contributes to this condition through several potential mechanisms, including damage to the blood brain barrier, increases in oxidative stress and inflammation in the brain, and impaired neurogenesis, each of which lead to neuronal dysfunction. A genetic predisposition to CRCI is the E4 allele of the Apolipoprotein E gene (APOE), which is also the strongest genetic risk factor for Alzheimer's disease. In normal brains, APOE performs essential lipid transport functions. The APOE4 isoform has been linked to altered lipid binding, increased oxidative stress and inflammation, reduced turnover of neural progenitor cells, and impairment of the blood brain barrier. As chemotherapy also affects these processes, the influence of APOE4 on CRCI takes on great significance. This review outlines the main areas where APOE genotype could play a role in CRCI. Potential therapeutics based on APOE biology could mitigate these detrimental cognitive effects for those receiving chemotherapy, emphasizing that the APOE genotype could help in developing personalized cancer treatment regimens.

The Anti-Inflammatory Drug Aspirin Does Not Protect Against Chemotherapy-Induced Memory Impairment by Paclitaxel in Mice

Inflammation has been proposed to play a causal role in chemobrain which—if true—would represent an opportunity to repurpose existing anti-inflammatory drugs for the prevention and treatment of chemobrain. Here, we show that the chemoagent paclitaxel induces memory impairment and anhedonia in mice within 24 h of treatment cessation, but inflammation is not present until 2 weeks after treatment. We find no evidence of brain inflammation as measured by cytokine analysis at any time point. Furthermore, treating with aspirin to block inflammation did not affect paclitaxel-induced memory impairment. These findings suggest that inflammation may not be responsible for memory impairment induced by paclitaxel. These results contrast with recent findings of a causal role for inflammation in cancer-induced memory deficits in mice that were prevented by treatment with oral aspirin, suggesting that cognitive impairment in cancer patients undergoing treatment may arise from multiple convergent mechanisms.

Social enrichment attenuates chemotherapy induced pro-inflammatory cytokine production and affective behavior via oxytocin signaling

Breast cancer survivors receiving chemotherapy often report increased anxiety and depression. However, the mechanism underlying chemotherapy-induced changes in affect remains unknown. We hypothesized that chemotherapy increases cytokine production, in turn altering exploratory and depressive-like behavior. To test this hypothesis, female Balb/C mice received two injections, separated by two weeks, of vehicle (0.9% saline) or a chemotherapeutic cocktail [9 mg/kg doxorubicin (A) and 90 mg/kg cyclophosphamide (C)]. Peripheral and central cytokine concentrations were increased one and seven days, respectively, after AC. Because of the beneficial effects of social enrichment on several diseases with inflammatory components, we examined whether social enrichment could attenuate the increase in peripheral and central cytokine production following chemotherapy administration. Socially isolated mice receiving AC therapy demonstrated increased depressive-like and exploratory behaviors with a concurrent increase in hippocampal IL-6. Whereas, group housing attenuated AC-induced IL-6 and depressive-like behavior. Next, we sought to determine whether central oxytocin may contribute to the protective effects of social housing after AC administration. Intracerebroventricular administration of oxytocin to socially isolated mice recapitulated the protective effects of social enrichment; specifically, oxytocin ameliorated the AC-induced effects on IL-6 and depressive-like behavior. Furthermore, administration of an oxytocin antagonist to group housed mice recapitulated the responses of socially isolated mice; specifically, AC increased depressive-like behavior and central IL-6. These data suggest a possible neuroprotective role for oxytocin following chemotherapy, via modulation of IL-6. This study adds to the growing literature detailing the negative behavioral effects of chemotherapy and provides further evidence that social enrichment may be beneficial to health.

Electroacupuncture trigeminal nerve stimulation plus body acupuncture for chemotherapy-induced cognitive impairment in breast cancer patients: An assessor-participant blinded, randomized controlled trial

Chemotherapy causes various side effects, including cognitive impairment, known as 'chemobrain'. In this study, we determined whether a novel acupuncture mode called electroacupuncture trigeminal nerve stimulation plus body acupuncture (EA/TNS + BA) could produce better outcomes than minimum acupuncture stimulation (MAS) as controls in treating chemobrain and other symptoms in breast cancer patients. In this assessor- and participant-blinded, randomized controlled trial, 93 breast cancer patients under or post chemotherapy were randomly assigned to EA/TNS + BA (n = 46) and MAS (n = 47) for 2 sessions per week over 8 weeks. The Montreal Cognitive Assessment (MoCA) served as the primary outcome. Digit span test was the secondary outcomes for attentional function and working memory. The quality of life and multiple functional assessments were also evaluated. EA/TNS + BA treated group had much better performance than MAS-treated group on reverse digit span test at Week 2 and Week 8, with medium effect sizes of 0.53 and 0.48, respectively, although no significant differences were observed in MoCA score and prevalence of chemobrain between the two groups. EA/TNS + BA also markedly reduced incidences of diarrhoea, poor appetite, headache, anxiety, and irritation, and improved social/family and emotional wellbeing compared to MAS. These results suggest that EA/TNS + BA may have particular benefits in reducing chemotherapy-induced working memory impairment and the incidence of certain digestive, neurological, and distress-related symptoms. It could serve as an effective intervention for breast cancer patients under and post chemotherapy (trial registration: https://www.clinicaltrials.gov: NCT02457039).

Pathogenesis, Assessments, and Management of Chemotherapy-Related Cognitive Impairment (CRCI): An Updated Literature Review

There are various cancer treatments at present, and chemotherapy is one of the main methods. Chemotherapy-related cognitive impairment (CRCI), as one of the side effects of chemotherapy, has gradually attracted the attention of more and more researchers. CRCI has been verified by subjective reports and objective neuropsychological tests so far. But oncologists' understanding of it and its treatments are still incomplete. In this review, we mainly give a comprehensive overview of the mechanism of CRCI, then describe a variety of evaluation methods, and finally summarize the treatment approaches under current medical conditions and compare it with an excellent article published in 2015 with the aim of providing directions for future research and better understanding of CRCI for clinicians.

Cellular mechanisms and treatments for chemobrain: insight from aging and neurodegenerative diseases

Chemotherapy is a life-saving treatment for cancer patients, but also causes long-term cognitive impairment, or "chemobrain", in survivors. However, several challenges, including imprecise diagnosis criteria, multiple confounding factors, and unclear and heterogeneous molecular mechanisms, impede effective investigation of preventions and treatments for chemobrain. With the rapid increase in the number of cancer survivors, chemobrain is an urgent but unmet clinical need. Here, we leverage the extensive knowledge in various fields of neuroscience to gain insights into the mechanisms for chemobrain. We start by outlining why the post-mitotic adult brain is particularly vulnerable to chemotherapy. Next, through drawing comparisons with normal aging, Alzheimer's disease, and traumatic brain injury, we identify universal cellular mechanisms that may underlie the cognitive deficits in chemobrain. We further identify existing neurological drugs targeting these cellular mechanisms that can be repurposed as treatments for chemobrain, some of which were already shown to be effective in animal models. Finally, we briefly describe future steps to further advance our understanding of chemobrain and facilitate the development of effective preventions and treatments.

Doxorubicin chemotherapy-induced "chemo-brain": Meta-analysis

Doxorubicin is a leading chemotherapeutic halting cellular replication and inducing p53-dependent apoptosis in cancerous tissue. Like many chemotherapies, doxorubicin damages healthy tissue throughout the body through cellular mechanisms independent of its chemotherapeutic action. Although cognitive impairment is commonly recorded in patients after chemotherapy, the occurrence of doxorubicin-induced "chemo-brain" is debated, as doxorubicin cannot cross the blood-brain barrier. However, the potential of indirect doxorubicin neurotoxicity remains, providing a foundation for doxorubicin-mediated chemo-brain. We present the first meta-analysis of defined cognitive performance of doxorubicin-treated patients. A search of PubMed and MedLine collected 494 studies, 14 of which met analysis criteria. Performance of 511 doxorubicin-treated women with breast cancer was compared to that of 306 healthy controls across measures of defined cognitive modalities. Treated patients experience significant impairment in global cognition compared to controls (g₌ -0.41, P < 0.001), with select impairment in executive function (g = -0.25, P < 0.0001), language (g = -0.30, P < 0.0001), memory (g = -0.12, P < 0.01) and processing speed (g = -0.28, P < 0.01). Within memory, short-term verbal memory is most significantly affected (g = -0.21, P < 0.01). Impairment in select cognitive modalities (executive function, language, memory, short-term verbal memory, processing speed) is prevalent in doxorubicin-treated patients, with some cognitive functions remaining intact (attention, motor function, visuospatial abilities). This information can guide the development of future interventions to improve quality-of-life (QOL) and doxorubicin-derived therapies that target cytotoxicity to cancerous tissue, avoiding healthy tissue damage, which is mediated by seemingly independent mechanisms.

Emerging mechanistic underpinnings and therapeutic targets for chemotherapy-related cognitive impairment

PURPOSE OF REVIEW

Modern innovations in cancer therapy have dramatically increased the number of cancer survivors. An unfortunately frequent side-effect of cancer treatment is enduring neurological impairment. Persistent deficits in attention, concentration, memory, and speed of information processing afflict a substantial fraction of cancer survivors following completion of these life-saving therapies. Here, we highlight chemotherapy-related cognitive impairment (CRCI) and discuss the current understanding of mechanisms underlying CRCI.

RECENT FINDINGS

New studies emphasize the deleterious impact of chemotherapeutic agents on glial-glial and neuron-glial interactions that shape the form, function and plasticity of the central nervous system. An emerging theme in cancer therapy-related cognitive impairment is therapy-induced microglial activation and consequent dysfunction of both neural precursor cells and mature neural cell types. Recent work has highlighted the complexity of dysregulated intercellular interactions involving oligodendrocyte lineage cells, microglia, astrocytes, and neurons following exposure to traditional cancer therapies such as methotrexate. This new understanding of the mechanistic underpinnings of CRCI has elucidated potential therapeutic interventions, including colony-stimulating factor 1 receptor inhibition, TrkB agonism, and aerobic exercise.

SUMMARY

Traditional cancer therapies induce lasting alterations to multiple neural cell types. Therapy-induced microglial activation is a critical component of the cause of CRCI, contributing to dysregulation of numerous processes of neural plasticity. Therapeutic targeting of microglial activation or the consequent dysregulation of neural plasticity mechanisms are emerging.

Post-chemotherapy cognitive impairment in hematological patients: current understanding of chemobrain in hematology

Introduction: Cognitive impairment caused by chemotherapies, a condition known as chemobrain, is a possible side effect that affects alertness, learning, memory, and concentration.Areas covered: Chemobrain has been principally investigated as a possible side-effect among cancer patients. However, numerous drugs used to treat hematological malignancies can determine the appearance of chemobrain. In this review, we have examined some commonly used drugs for the treatment of hematological malignancies which are known to have a deleterious action on cognitive functions.Numerous mechanisms have been suggested, comprising the direct neurotoxicity of chemotherapeutic drugs, oxidative stress, genetic predisposition, cytokine-provoked damage, histone modifications, immune alteration, and the action of chemotherapeutic on trophic factors and structural proteins of brain cells.Expert commentary: Cognitive dysfunction provoked by the treatment of hematological diseases is an actual challenge in clinical practice. Actually, there are no totally efficient and innocuous treatments for this syndrome. It is important that further investigations specify the existence of predictors and gravity factors to pre- and post-therapy cognitive change and identify the influence of tumor treatments on the cognitive alterations in long-term, cancer survivors. Moreover, future studies are needed to analyze the interactions between genetic risk, amyloid accumulation, intrinsic brain networks, and chemotherapy.

Manganese-Enhanced Magnetic Resonance Imaging: Application in Central Nervous System Diseases

Manganese-enhanced magnetic resonance imaging (MEMRI) relies on the strong paramagnetism of Mn2+. Mn2+ is a calcium ion analog and can enter excitable cells through voltage-gated calcium channels. Mn2+ can be transported along the axons of neurons via microtubule-based fast axonal transport. Based on these properties, MEMRI is used to describe neuroanatomical structures, monitor neural activity, and evaluate axonal transport rates. The application of MEMRI in preclinical animal models of central nervous system (CNS) diseases can provide more information for the study of disease mechanisms. In this article, we provide a brief review of MEMRI use in CNS diseases ranging from neurodegenerative diseases to brain injury and spinal cord injury.

Plausible biochemical mechanisms of chemotherapy-induced cognitive impairment ("chemobrain"), a condition that significantly impairs the quality of life of many cancer survivors

Increasing numbers of cancer patients survive and live longer than five years after therapy, but very often side effects of cancer treatment arise at same time. One of the side effects, chemotherapy-induced cognitive impairment (CICI), also called "chemobrain" or "chemofog" by patients, brings enormous challenges to cancer survivors following successful chemotherapeutic treatment. Decreased abilities of learning, memory, attention, executive function and processing speed in cancer survivors with CICI, are some of the challenges that greatly impair survivors' quality of life. The molecular mechanisms of CICI involve very complicated processes, which have been the subject of investigation over the past decades. Many mechanistic candidates have been studied including disruption of the blood-brain barrier (BBB), DNA damage, telomere shortening, oxidative stress and associated inflammatory response, gene polymorphism of neural repair, altered neurotransmission, and hormone changes. Oxidative stress is considered as a vital mechanism, since over 50% of FDA-approved anti-cancer drugs can generate reactive oxygen species (ROS) or reactive nitrogen species (RNS), which lead to neuronal death. In this review paper, we discuss these important candidate mechanisms, in particular oxidative stress and the cytokine, TNF-alpha and their potential roles in CICI.

Chemotherapy-Induced Cognitive Impairment Is Associated with Increased Inflammation and Oxidative Damage in the Hippocampus

Increasing evidence indicates that chemotherapy results in long-term effects on cognitive dysfunction in some cancer survivors. While many studies have established the domains of cognition and corresponding regions in the brain most affected, little is revealed about the potential molecular mechanisms that mediate these adverse changes after treatment. The effects of chemotherapy on the brain are likely attributed to various mechanisms, including oxidative stress and immune dysregulation, features that are also reminiscent of cognitive aging. We have investigated the cognitive effects of a cocktail composed of doxorubicin and cyclophosphamide (AC-chemo) in a surgical ovariectomized rodent model. In this study, we address whether the levels of pro-inflammatory cytokines and oxidative stress-responsive gene markers are altered in the CNS of rats treated with systemic AC-chemo. We further evaluated the levels of nucleic acids modified by oxidative stress in the hippocampus using both immunohistochemical and Northern blotting techniques with a monoclonal antibody against 8-hydroxyguanosine (8-OHG) and 8-OHdG base lesions. We demonstrate that ERK 1/2 and JNK/SAPK signaling activities are elevated in the hippocampus of AC-chemo rats. The levels of pro-inflammatory, oxidative stress-responsive, and RNA/DNA damage markers were also higher in drug-injected animals relative to saline controls. The results indicate that the effects of AC chemotherapy are associated with oxidative damage and a global stress response in the hippocampus. These alterations in the molecular signature of the brain may underlie the processes that contribute to cognitive impairment after treatment.

Chemobrain as a Product of Growing Success in Chemotherapy - Focus on Glia as both a Victim and a Cure

Chemotherapy-induced cognitive impairment or chemobrain is a frequent consequence of cancer treatment with many psychiatric features. Ironically, the increasing efficacy of chemotherapy leaves growing number of patients alive with chemobrain. Therefore, there is an urgent need for strategies capable of returning cancer survivors back to their pre-morbid quality of life. Molecular mechanisms of chemobrain are largely unknown. Over the last decade there was a lot of emphasis in preclinical research on inflammatory consequences of chemotherapy and oxidative stress but so far none of these approaches were translated into clinical scenario. The co-administration of chemotherapy with protective agents was evaluated preclinically but it should be introduced with caution as potential interference was not yet studied and that could blunt therapeutic efficacy. Stem cell-based regenerative medicine approach has so far been exploited very sparsely in the context of chemobrain and the focus was on indirect mechanisms or neuronal replacement in the hippocampus. However, there is evidence for widespread white matter abnormalities in patients with chemobrain. This is quite logical considering life-long proliferation and turnover of glial cells, which makes them vulnerable to chemotherapeutic agents. Feasibility of glia replacement has been established in mice with global dysmyelination where profound therapeutic effect has been observed but only in case of global cell engraftment (across the entire brain). While global glia replacement has been achieved in mice translation to clinical setting might be challenging due to much larger brain size. Therefore, a lot of attention should be directed towards the route of administration to accomplish widespread cell delivery. Techniques facilitating that broad cell distribution including intra-arterial and intrathecal methods should be considered as very compelling options. Summarizing, chemobrain is a rapidly growing medical problem and global glia replacement should be considered as worthwhile therapeutic strategy.