Chemotherapy, cognitive impairment and hippocampal toxicity

Neurobehavioral manifestations in female rats after intermittent exposure to an anticancer agent, paclitaxel

Paclitaxel (PTX), a widely used chemotherapeutic agent, causes both peripheral and central neurotoxicity, leading to significant behavioral impairments. However, inadequate literature is available on PTX-induced neurobehavioral sequelae associated with anxiety, depression, and cognition in adults during and after chemotherapy. Therefore, the present study aimed to investigate neurobehavioral impairments in adult female rats following PTX exposure, with a specific focus on anxiety-like behaviors and cognitive functions such as learning and memory. In this study, we used adult female Wistar rats aged 10-12 weeks (average weight: 180 ± 5 g) and administered clinically relevant therapeutic doses of PTX (1.6 and 3.2 mg/kg body weight) intravenously once weekly for 6 weeks, simulating the clinical chemotherapy regimen. Neurobehavioral assessments were conducted after the first and sixth doses of PTX using validated mazes, including the photoactometer, open-field maze, elevated plus-maze (EPM; for anxiety-like behaviors), and the step-down latency test (SDL; for cognitive performance). Neurobehavioral patterns were recorded using autotracking software (ANY-maze, Stoelting Co., Wood Dale, Illinois, USA). Our findings revealed substantially reduced locomotor activity in the photoactometer, increased anxiety-like behaviors with amplified fear emotionality in the open-field and EPM tests, and memory impairment in the SDL test. These results suggest that the manifestation of anxiogenic and cognitive behavioral changes is associated with the administration of a higher dose (3.2 mg/kg) of PTX. In conclusion, our study indicates that PTX causes significant neurobehavioral impairments in rats after exposure to equivalent therapeutic doses of PTX.

Using a murine model to explore the impact of sex and APOE4 on cisplatin-induced cognitive impairment

Chemotherapy-induced cognitive impairment (CICI) is reported in over 35% of cancer survivors. Understanding risk factors for the development of CICI may provide insight into mechanisms and treatment. Being female and carrying the E4 allele of the APOE gene are risk factors for late-onset Alzheimer's disease, and there is emerging evidence that they may also confer risk for CICI. We sought to investigate these factors in a middle-aged (8-9 months) murine model of CICI. We used a 2 (+/- cisplatin) x 2 (male/female) x 2 (wild-type/APOE4 transgenic) factorial design in which cisplatin, or an equal volume of saline vehicle, was administered at 2.3 mg/kg/day for 5 days for 2 rounds separated by a 5-day rest. Behavioral tests of cognition and activity were evaluated one month after treatment completion followed by tissue collection. Male mice exhibited more severe weight loss following cisplatin, irrespective of genotype. Cisplatin was also associated with reduced open-field and nest building activity for both sexes and genotypes. In the puzzle box task, cisplatin treatment reduced performance in the task with indication that sex and genotype trial dependently modulated performance. In the novel object task, male mice of both genotypes showed cisplatin-induced deficits. In analyzing tissue, we did not note significant cisplatin-induced neuroinflammatory processes. We did observe an effect of cisplatin on brain Bdnf mRNA expression that varied by brain region, sex, and genotype. Within the hippocampus, cisplatin reduced Bdnf in male mice but mildly elevated it within female mice; within the frontal cortex, Bdnf expression was reduced by cisplatin in both sexes but more severely in APOE4 mice. Overall, our data provide evidence that both sex and genotype may modulate the effect of cisplatin on the brain and on cognitive performance.

Nose-to-brain Drug Delivery System: An Emerging Approach to Chemotherapy-induced Cognitive Impairment

The rise in global cancer burden, notably breast cancer, emphasizes the need to address chemotherapy-induced cognitive impairment, also known as chemobrain. Although chemotherapy drugs are effective against cancer, they can trigger cognitive deficits. This has triggered the exploration of preventive strategies and novel therapeutic approaches. Nanomedicine is evolving as a promising tool to be used for the mitigation of chemobrain by overcoming the blood-brain barrier (BBB) with innovative drug delivery systems. Polymer and lipid-based nanoparticles enable targeted drug release, enhancing therapeutic effectiveness. Utilizing the intranasal route of administration may facilitate drug delivery to the central nervous system (CNS) by circumventing first-pass metabolism. Therefore, knowledge of nasal anatomy is critical for optimizing drug delivery via various pathways. Despite challenges, nanoformulations exhibit the potential in enhancing brain drug delivery. Continuous research into formulation techniques and chemobrain mechanisms is vital for developing effective treatments. The intranasal administration of nanoformulations holds promise for improving therapeutic outcomes in chemobrain management. This review offers insights into potential future research directions, such as exploring novel drug combinations, investigating alternative delivery routes, or integrating emerging technologies to enhance the efficacy and safety of nanoformulations for chemobrain management.

Mapping glioma's impact on cognition: Insights from macrostructure, microstructure, and beyond

Background

Cognitive impairment (CI) significantly impacts the quality of life of glioma patients. The main contributing risk factors include tumor characteristics, treatment-related factors, and their complex interplay. This review explores the role of advanced structural neuroimaging techniques in understanding CI in glioma patients.

Methods

A literature search was conducted in PubMed, PsycINFO, and ISI Web of Knowledge using specific keywords. We included studies with advanced magnetic resonance imaging techniques and objective neuropsychological exams.

Results

At diagnosis, during the pre-surgery phase, associations between glioma characteristics and cognitive outcomes have been described. Specifically, patients with isocitrate dehydrogenase (IDH)-wild-type gliomas exhibit more adverse cognitive outcomes, accompanied by disruptions in gray (GM) and white matter (WM) networks when compared to IDH-mutant. In addition, pre- and post-surgery imaging analyses highlight the importance of preserving specific WM tracts, such as the inferior longitudinal and arcuate fasciculus, in mitigating verbal memory and language processing decline. Furthermore, examining gliomas in perisylvian regions emphasizes deleterious effects on various cognitive domains. Additionally, it has been suggested that neuroplastic reorganization could serve as a compensatory mechanism against CI. Lastly, a limited number of studies suggest long-term CI linked to GM atrophy and leukoencephalopathy induced by radiotherapy ± chemotherapy in glioma survivors, highlighting the need for improving treatment approaches, particularly for patients with extended survival expectations.

Conclusion

This review underscores the need for nuanced understanding and an individual approach in the management of glioma patients. Neuroplastic insights offer clinicians valuable guidance in surgical decision-making and personalized therapeutic approaches thus improving patient outcomes in neuro-oncology.

Acute Neurotoxicity in Children Treated for Acute Lymphoblastic Leukemia and Lymphoblastic Lymphoma: A 10-Year Single-Centre Experience

Background: Recent advances in childhood acute lymphoblastic leukemia (ALL) and lymphoblastic lymphoma (LL) management provide higher survival rates at the cost of increased toxicities. Acute neurotoxicity affects up to 10% of patients, requiring rapid recognition and treatment. Methods: A retrospective observational study was performed to determine the frequency, clinical manifestations, radiological characteristics, treatment options and outcome of acute neurological adverse events in pediatric patients with lymphoid malignancies at the Department of Oncology and Hematology, Children's Hospital Zagreb, Croatia. Results: A total of 56 patients (48 ALL and 8 LL, male/female ratio 1:1, average age 5.4 years) were treated mainly according to the ALL-IC BFM 2009 protocol. The B-immunophenotype was the most frequent (85.7%). Most patients were stratified to the intermediate risk group (39.3%), and two were initially diagnosed with central nervous system infiltration. Acute neurotoxic events were registered in 11 patients (19.6%), most commonly in the 6-10-year age group (66.7%), predominately in females (72.7%) and high-risk group (54.5%). The most frequent clinical presentation was seizures (83.3%), with status epilepticus in four cases. We detected electroencephalogram (EEG) irregularities in almost all patients and various morphological changes in the brain magnetic resonance imaging (MRI), most often consistent with posterior reversible encephalopathy syndrome and leukoencephalopathy. Approximately half the patients received prolonged antiepileptic therapy. No apparent residual neurologic manifestations have been observed. Conclusions: Acute neurotoxicity is a rather frequent treatment-related adverse event, associated with high-risk disease. Early recognition and timely management are essential for rapid recovery and optimal outcomes.

Characterizing changes in executive functions and performance in daily activities after chemotherapy: A pre-post mixed-methods study protocol

BACKGROUND

Impairments in higher cognitive abilities (termed executive functions (EF) are common among individuals with cancer following chemotherapy and may impact their performance of daily activities. Our aim is to better understand the changes in EF and the impact on performance in daily activities of individuals with cancer pre- and post-chemotherapy.

METHODS

A convergent parallel mixed-method pre-post experimental design. Qualitative and quantitative data will be collected pre- and post-chemotherapy (12 weeks following chemotherapy commencement). Participants will be adult candidates for chemotherapy who are newly diagnosed with non-central nervous system malignancy, stages I-III. The Canadian Occupational Performance Measure will assess the performance of daily activities; secondary measures include EF, cognitive functioning, fatigue, and emotional well-being. Qualitative data will be collected via open-ended questions. Pre- and post-chemotherapy, quantitative and qualitative data will be analyzed separately and merged into an overall interpretation. It is expected that, pre-chemotherapy, no difficulties in performing daily activities will be revealed. Post-chemotherapy EF impairments will be apparent and their impact on the performance of daily activities will be identified.

CONCLUSIONS

Integrating quantitative and qualitative measures will contribute to a comprehensive understanding of the individuals' cognitive needs and may enable the development of effective interventions to minimize deterioration in daily activities after chemotherapy.

Altered Mental Status in Cancer

Patients with cancer experience high rates of alterations in mental status. The mechanisms for altered mental status (AMS) in this population are manifold. The cancer itself may cause AMS through direct invasion of the central nervous system or as metastatic leptomeningeal spread. However, cancer patients are also vulnerable to tumor-associated complications such as seizures, cerebral edema, strokes, or cancer treatment-related complications such as infections, direct neural injury from radiation or chemotherapy, edema, or dysregulated autoimmune response from immunotherapies. Both during treatment and as sequelae, patients may suffer neurocognitive complications from chemotherapy and radiation, medications or opportunistic infections, as well as toxic-metabolic, nutritional, and endocrine complications. In this review, we describe a clinical approach to the cancer patient presenting with AMS and discuss the differential drivers of AMS in this patient population. While common etiologies of AMS in noncancer patients (toxic-metabolic or infectious encephalopathy, delirium) are also applicable to cancer patients, we additionally provide a cancer-specific differential diagnosis that warrants special consideration in the cancer patient with AMS.

Nanotechnology Approaches for Prevention and Treatment of Chemotherapy-Induced Neurotoxicity, Neuropathy, and Cardiomyopathy in Breast and Ovarian Cancer Survivors

Nanotechnology has emerged as a promising approach for the targeted delivery of therapeutic agents while improving their efficacy and safety. As a result, nanomaterial development for the selective targeting of cancers, with the possibility of treating off-target, detrimental sequelae caused by chemotherapy, is an important area of research. Breast and ovarian cancer are among the most common cancer types in women, and chemotherapy is an essential treatment modality for these diseases. However, chemotherapy-induced neurotoxicity, neuropathy, and cardiomyopathy are common side effects that can affect breast and ovarian cancer survivors quality of life. Therefore, there is an urgent need to develop effective prevention and treatment strategies for these adverse effects. Nanoparticles (NPs) have extreme potential for enhancing therapeutic efficacy but require continued research to elucidate beneficial interventions for women cancer survivors. In short, nanotechnology-based approaches have emerged as promising strategies for preventing and treating chemotherapy-induced neurotoxicity, neuropathy, and cardiomyopathy. NP-based drug delivery systems and therapeutics have shown potential for reducing the side effects of chemotherapeutics while improving drug efficacy. In this article, the latest nanotechnology approaches and their potential for the prevention and treatment of chemotherapy-induced neurotoxicity, neuropathy, and cardiomyopathy in breast and ovarian cancer survivors are discussed.

Wnt3a/GSK3β/β-catenin Signalling Modulates Doxorubicin-associated Memory Deficits in Breast Cancer

BACKGROUND

Chemobrain is widespread in breast cancer patients receiving chemotherapy. However, the exact mechanism, especially the associated signalling pathway, is not currently clear. This study was to evaluate the behavioural changes in breast cancer mice after chemotherapy and to further explore the role of Wnt3a/glycogen synthase kinase (GSK3β)/β-catenin signalling in chemobrain.

METHODS

MMTV-PyMT(+) breast cancer mice were injected intraperitoneally with doxorubicin (4 mg/kg) once a week for three weeks to establish a chemobrain model. The Morris water maze (MWM) and novel object recognition (NOR) tests were performed to assess the learning and memory ability. Electron microscopy was used to observe the structural changes in the hippocampal CA1 region. The brain tissue of breast cancer mice after chemotherapy was taken out for mRNA-seq detection. Then, the expression levels and phosphorylation of key proteins in the Wnt3a/GSK3 β/β-catenin signalling pathway were evaluated through Western blotting (WB) and immunofluorescence.

RESULTS

Doxorubicin-induced spatial and short-term memory impairment was observed in breast cancer mice, and obvious neuronal damage could be seen in the hippocampal CA1 region. Immunofluorescence staining for GSK3β was increased. Wnt signalling pathway is highly enriched from mRNA-seq analysis, with GSK3β genes at important nodes. The relative protein levels of p-PI3K, p-AKT, p-GSK3 β, Wnt3a and TCF-1 were decreased significantly, while the p-β-catenin level was increased. After injection of the GSK3β inhibitor sb216763 (1 ng/0.5 µl/side), hippocampal neuronal injury was alleviated to some extent, and the changes in the expression of proteins upstream and downstream of this signalling pathway were reversed.

CONCLUSION

Wnt3a/GSK3 β/β-catenin signalling is likely involved in doxorubicin-induced memory impairment. This result provides basic evidence for the further study of chemobrain in breast cancer.

Modern Radiation Treatment Planning Parameters and Outcomes in Pediatric Tectal Gliomas

Purpose

Pediatric low-grade tectal gliomas are rare, indolent tumors of the brain stem. We reviewed outcomes of pediatric patients who received a diagnosis of low-grade tectal gliomas and report dosimetric parameters for those receiving radiation therapy (RT).

Methods and Materials

We retrospectively reviewed all pediatric patients (age <18 years) at our institution diagnosed with a low-grade glioma between 1993 and 2020 (n = 288). Twenty-three patients with tectal gliomas were identified. Patients who received RT (n = 8) had detailed dosimetric analyses performed. Doses to critical structures and any resulting toxicities were reviewed. Minimum follow-up was 2 years and complete follow-up was available for all patients.

Results

Twenty-three patients, with a median age of 8.9 years, were included (range, 0.5-16.2 years). At a median follow-up of 7.4 years (range, 2-24 years), all were alive at the end of the study period. Three patients (13%) were treated with upfront RT; none of these patients developed local failure (LF) after a median follow-up of 10.6 years. One patient was treated with upfront chemotherapy with no evidence of progression afterward. Nineteen patients were initially observed after diagnosis and 26% of them (n = 5) experienced local progression. All 5 were treated with salvage RT, with 1 patient requiring further treatment with chemotherapy. Fractionation schedules for patients undergoing upfront or salvage RT included 50.4 Gy in 28 fractions (n = 4), 54 Gy in 30 fractions (n = 2), and 51 Gy in 30 fractions (n = 2). For patients treated after 2007, the gross tumor volume was delineated on a T2 magnetic resonance imaging with an average gross tumor volume-to-planning target volume expansion of 4.5 mm (range, 3-5 mm). Detailed dosimetric parameters were available for all patients treated with RT.

Conclusions

Our review supports the indolent behavior for most tectal gliomas. For the subset of tumors with evidence of progression, modern photon RT results in excellent oncologic outcomes with minimal late effects.

Implication of M2 macrophage on NLRP3 inflammasome signaling in mediating the neuroprotective effect of Canagliflozin against methotrexate-induced cognitive impairment

Methotrexate (MTX), a chemotherapeutic antimetabolite, has been linked to cognitive impairment in cancer patients. MTX-induced metabolic pathway disruption may result in decreased antioxidant activity and increased oxidative stress, influencing hippocampal neurogenesis and microglial activation. Nuclear factor-kappa B (NF-κB), an oxidative stress byproduct, has been linked to MTX toxicity via the activation of NLRP3 inflammasome signaling. Macrophage activation and polarization plays an important role in tissue injury. This differentiation may be mediated via either the Toll-like receptor 4 (TLR4) or NLRP3 inflammasome. Interestingly, Canagliflozin (CANA), a sodium-glucose cotransporter 2 (SGLT2) inhibitor has been recently reported to exert anti-inflammatory effects by modulating macrophage polarization balance. This study aimed to investigate CANA's protective effect against MTX-induced cognitive impairment, highlighting the possible involvement of TLR4/ NF-κB crosstalk with NLRP3 inflammasome activation and macrophage polarization. Forty-eight Male Wistar rats were divided into 4 groups; (1) received saline orally for 30 days and intravenously on days 8 and 15. (2) received Canagliflozin (CANA; 20 mg/kg/day; p.o.) for 30 days. (3) received MTX (75 mg/kg, i.v.) on day 8 and 15, then they were injected with four i.p. injections of leucovorin (LCV): the first dose was 6 mg/ kg after 18 h, and the remaining doses were 3 mg/kg after 26, 42, and 50 h of MTX administration. (4) received MTX and LCV as in group 3 in addition to CANA as in group 2. MTX-treated rats showed cognitive deficits in spatial and learning memory as evidenced in the novel object recognition and Morris water maze tests. MTX exerted an oxidative effect which was evident by the increase in MDA and decline in SOD, GSH and GPx. Moreover, it exerted an inflammatory effect via elevated caspase-1, IL-1β and IL-8. CANA treatment restored cognitive ability, reduced MTX-induced oxidative stress and neuroinflammation via attenuation of TLR4/NF-κB/NLRP3 signaling, and rebalanced macrophage polarization by promoting the M2 phenotype. Hence, targeting molecular mechanisms manipulating macrophage polarization may offer novel neuroprotective strategies for preventing or treating MTX-induced immune modulation and its detrimental sequel.

The Mechanisms Underlying the Beneficial Impact of Aerobic Training on Cancer-Related Fatigue: A Conceptual Review

Cancer-related fatigue (CRF) is a prevalent and persistent issue affecting cancer patients, with a broad impact on their quality of life even years after treatment completion. The precise mechanisms underlying CRF remain elusive, yet its multifaceted nature involves emotional, physical, and cognitive dimensions. The absence of effective medical treatments has prompted researchers to explore integrative models for potential insights. Notably, physical exercise emerges as a promising strategy for managing CRF and related symptoms, as studies showed a reduction in CRF ranging from 19% to 40%. Current recommendations highlight aerobic training at moderate intensity as beneficial, although questions about a dose-response relationship and the importance of exercise intensity persist. Despite the positive impact of exercise on CRF, the underlying mechanisms remain elusive. This review aims to provide a theoretical model explaining how aerobic exercise may alleviate CRF. Focusing on acute exercise effects, this review delves into the potential influence on peripheral and neural inflammation, immune function dysregulation, and neuroendocrine system disruptions. The objective is to enhance our understanding of the intricate relationship between exercise and CRF, ultimately paving the way for tailored interventions and potential pharmacological treatments for individuals unable to engage in physical exercise.

The ameliorative effects of cannabidiol on methotrexate-induced neuroinflammation and neuronal apoptosis via inhibiting endoplasmic reticulum and mitochondrial stress

Methotrexate (MTX) is an antineoplastic agent and has neurotoxic effects. It exerts its toxic effect on the brain by triggering inflammation and apoptosis. Cannabidiol (CBD) is an agent known for its antioxidant, anti-inflammatory effects in various tissues. The aim of this study is to examine the protective effects of CBD treatment in various brain structures from MTX damage and to evaluate the effect of intracellular pathways involved in apoptosis. Thirty-two adult Wistar Albino female rats were divided into four groups as control, MTX (20 mg/kg intraperitoneally [i.p.]), MTX + CBD (0.1 mL of 5 mg/kg i.p.), and CBD (for 7 days, i.p.). At the end of the experiment, brain tissues collected for biochemical analyses as total oxidant status (TOS), total antioxidant status, oxidative stress index (OSI), histopathological and immunohistochemical analyses as tumor necrosis factor-α (TNF-α), serotonin, mammalian target of rapamycin (mTOR) staining, genetic analyses as caspase-9 (Cas-9), caspase-12 (Cas-12), C/EBP homologous protein (CHOP), and cytochrome-c (Cyt-c) gene expressions. In the histopathological and immunohistochemical evaluation, hyperemia, microhemorrhage, neuronal loss, and significant decreasing expressions of seratonin were observed in the cortex, hippocampus, and cerebellum regions in the MTX group. mTOR, TNF-α, Cas-9, Cas-12, CHOP, and Cyt-c expressions with TOS and OSI levels were increased in the cortex. It was observed that these findings were reversed after CBD application in all regions. MTX triggers neuronal apoptosis via endoplasmic reticulum and mitochondrial stress while destroying serotonergic neurons. The reversal of the pathological changes with CBD treatment proves that it has anti-inflammatory and antiapoptotic activity in brain.

Effects of mammary cancer and chemotherapy on neuroimmunological markers and memory function in a preclinical mouse model

Treatment modalities for breast cancer, including cyclophosphamide chemotherapy, have been associated with the development of cognitive decline (CRCD), which is characterized by impairments in memory, concentration, attention, and executive functions. We and others have identified a link between inflammation and decreased cognitive performance in patients with breast cancer receiving chemotherapy. In order to better understand the inflammation-associated molecular changes within the brain related to tumor alone or in combination with chemotherapy, we orthotopically implanted mouse mammary tumors (E0771) into female C57BL/6 mice and administered clinically relevant doses of cyclophosphamide and doxorubicin intravenously at weekly intervals for four weeks. We measured serum cytokines and markers of neuroinflammation at 48 h and up to one month post-treatment and tested memory using a reward-based delayed spatial alternation paradigm. We found that breast tumors and chemotherapy altered systemic inflammation and neuroinflammation. We further found that the presence of tumor and chemotherapy led to a decline in memory over time at the longest delay, when memory was the most taxed, compared to shorter delay times. These findings in a clinically relevant mouse model shed light on possible biomarkers for CRCD and add to the growing evidence that anti-inflammatory strategies have the potential to mitigate cancer- or treatment-related side effects.

Neuropsychological functioning during chemotherapy with temozolomide in high-grade glioma patients: a retrospective single centre study

PURPOSE

starting from a lack of precise and coherent data in literature, aim of this work is to retrospectively study the influence of chemotherapy with Temozolomide (TMZ) on a wide series of neuropsychological functions in a population of adult high-grade glioma patients.

METHODS

an extensive neuropsychological battery was administered pre-operatively (T0) and after 6 (T1) and 12 months (T2) from surgery. After full recovery from surgery, TMZ was delivered concomitant to radiotherapy and, subsequently, adjuvantly for 5-day cycles per month. Parametric and non-parametric analyses were conducted to verify the influence of several aspects of chemotherapy on the adjusted scores of each cognitive test at the two post-operative follow-ups.

RESULTS

Sixty-one patients were included at T0; patients with a lower adjuvant TMZ dosage reported a better performance at the visual attention test at T1, and at the deductive reasoning test at T2. Undergoing more than 8 cycles of adjuvant therapy was slightly associated with a better performance at the long-term verbal memory tasks at T2. No other associations were found with the other cognitive tests and autonomy scales administered.

CONCLUSIONS

TMZ proved to be a secure treatment with no negative side effects on cognition and on level of daily autonomy, even at the highest dosage used. This is a positive finding which enables clinicians to reassure patients about the absence of significant negative effects of TMZ on their daily life functioning. In this view, eventual cognitive changes during treatment might not be attributed to chemotherapy but to other events such as tumour relapse.

Cladribine induces apoptosis, neuroinflammation, mitochondrial oxidative stress, tau phosphorylation and Aβ (1-42) pathway in the hippocampus: An in vivo approach

Cladribine is a purine nucleoside found to enhance toxic amyloid protein and cause memory impairment. Patients following chemotherapy treatment commonly suffer from cognitive deficits more prevalent in the elderly than adults. A previous research study revealed that cladribine has a high affinity to the brain, increases the level of amyloid precursor protein, and results in learning deficits. The study was designed to validate an animal model of cladribine administration to rats through mitochondrial oxidative stress, inflammation, apoptosis, tau phosphorylation, and amyloid-β (1-42) accumulation. In this study, all rats were orally given cladribine (0.5 and 1 mg/kg) for 28 days, resulting in impaired spatial memory confirmed by behavioural activity. On day 29, all rats were euthanized, and the hippocampal tissues were isolated and used for the estimation of neuroinflammatory markers, biochemicals parameters (glutathione, catalase, lipid peroxidation, and nitrite), amyloid-β (1-42) level, neurotransmitters, and nuclear factor kappa B analysis. Cladribine administration significantly elevated cytokines release, dysbalanced neurotransmitter concentration, and promoted the Aβ accumulation and hyperphosphorylation of tau protein. Our study outcome confirmed that cladribine produces cognitive impairment via activation of Nuclear factor kappa B, mitochondrial oxidative stress and dysbalanced of the endogenous antioxidant defence system.

The preventive effects of Centaurea maroccana Ball. extract against oxidative stress induced by cisplatin in mice brains: in vitro and in vivo studies

Since antiquity, Centaurea species have been used in folk medicine to treat several diseases owing to their potential biological activities that distinguish this genus such as antioxidant, anticancer, and anti-inflammatory effect. The current study aimed to investigate the possible neuroprotective effects of the n-butanol extract of Centaurea maroccana (BECM) against cisplatin (CP) induced neurotoxicity in mice. BECM's potential neuroprotective properties were studied in vitro and in vivo models. Male Swiss albino mice were orally received BECM (200 mg/kg) for 10 days before a single intraperitoneal injection of cisplatin (8 mg/kg). Vitamin E (100 mg/kg) was given daily by gavage as a positive control. In vitro results revealed that BECM inhibited lipid peroxidation (LPO) levels and acetylcholinesterase (AChE) activity. In vivo findings showed that BECM pretreatment was able to regulate lactate dehydrogenase (LDH) levels and to improve CP-induced cholinergic dysfunction by inhibiting AChE activity in mice brains. Moreover, BECM attenuated CP-provoked oxidative stress by suppressing LPO levels, increasing total antioxidant capacity (TAC) and enhancing the activities of antioxidant enzymes (catalase (CAT), superoxide dismutase (SOD), reduced glutathione (GSH), glutathione peroxidase (GPx) and glutathione S-transferase (GST)) in both brain cytosolic and mitochondrial fractions. The histological analysis exhibited neurotoprotective effect of BECM by protecting the cerebral cortex and reducing the histomorphological alterations resulted by cisplatin. Interestingly, our extract achieved neuroprotection comparable to vitamin E in most evaluated parameters. It appears that protective potency of BECM against CP-induced neurotoxicity could be related to its richness in polyphenols confirmed by liquid-chromatography tandem mass spectrometry analysis (LC-MS/MS).

Neuroprotective effect of herbal extracts inhibiting soluble epoxide hydrolase (sEH) and cyclooxygenase (COX) against chemotherapy-induced cognitive impairment in mice

Chemotherapy-induced cognitive impairment (CICI) is a novel clinical condition characterized by memory, learning, and motor function deficits. Oxidative stress and inflammation are potential factors contributing to chemotherapy's adverse effects on the brain. Inhibition of soluble epoxide hydrolase (sEH) has been proven effective in neuroinflammation and reversal of memory impairment. The research aims to evaluate the memory protective effect of sEH inhibitor and dual inhibitor of sEH and COX and compare its impact with herbal extracts with known nootropic activity in an animal model of CICI. In vitro sEH, the inhibitory activity of hydroalcoholic extracts of Sizygium aromaticum, Nigella sativa, and Mesua ferrea was tested on murine and human sEH enzyme as per the protocol, and IC50 was determined. Cyclophosphamide (50 mg/kg), methotrexate (5 mg/kg), and fluorouracil (5 mg/kg) combination (CMF) were administered intraperitoneally to induce CICI. The known herbal sEH inhibitor, Lepidium meyenii and the dual inhibitor of COX and sEH (PTUPB) were tested for their protective effect in the CICI model. The herbal formulation with known nootropic activity viz Bacopa monnieri and commercial formulation (Mentat) were also used to compare the efficacy in the CICI model. Behavioral parameter such as cognitive function was assessed by Morris Water Maze besides investigating oxidative stress (GSH and LPO) and inflammatory (TNFα, IL-6, BDNF and COX-2) markers in the brain. CMF-induced CICI, which was associated with increased oxidative stress and inflammation in the brain. However, treatment with PTUPB or herbal extracts inhibiting sEH preserved spatial memory via ameliorating oxidative stress and inflammation. S. aromaticum and N. sativa inhibited COX2, but M. Ferrea did not affect COX2 activity. Lepidium meyenii was the least effective, and mentat showed superior activity over Bacopa monnieri in preserving memory. Compared to untreated animals, the mice treated with PTUPB or hydroalcoholic extracts showed a discernible improvement in cognitive function in CICI.

The Ameliorative Effect of Pioglitazone against Neuroinflammation Caused by Doxorubicin in Rats

Doxorubicin (DOX) is a chemotherapeutic agent that is linked with complications such as cardiotoxicity and cognitive dysfunction, known as chemobrain. Chemobrain affects up to 75% of cancer survivors, and there are no known therapeutic options for its treatment. This study aimed to determine the protective effect of pioglitazone (PIO) against DOX-induced cognitive impairment. Forty Wistar female rats were equally divided into four groups: control, DOX-treated, PIO-treated, and DOX + PIO-treated. DOX was administered at a dose of 5 mg/kg, i.p., twice a week for two weeks (cumulative dose, 20 mg/kg). PIO was dissolved in drinking water at a concentration of 2 mg/kg in the PIO and DOX-PIO groups. The survival rates, change in body weight, and behavioral assessment were performed using Y-maze, novel object recognition (NOR), and elevated plus maze (EPM), followed by estimation of neuroinflammatory cytokines IL-6, IL-1β, and TNF-α in brain homogenate and RT-PCR of a brain sample. Our results showed a survival rate of 40% and 65% in the DOX and DOX + PIO groups, respectively, compared with a 100% survival rate in the control and PIO treatment groups at the end of day 14. There was an insignificant increase in body weight in the PIO group and a significant reduction in the DOX and DOX + PIO groups as compared with the control groups. DOX-treated animals exhibited impairment of cognitive function, and the combination PIO showed reversal of DOX-induced cognitive impairment. This was evidenced by changes in IL-1β, TNF-α, and IL-6 levels and also by mRNA expression of TNF- α, and IL-6. In conclusion, PIO treatment produced a reversal of DOX-induced memory impairment by alleviating neuronal inflammation by modulating the expression of inflammatory cytokines.

Hippocampal neuroinflammation following combined exposure to cyclophosphamide and naproxen in ovariectomized mice

Aim: Cancer patients undergoing chemotherapy report cognitive changes collectively termed "chemo brain." Neuroinflammation is among the factors believed to contribute to "chemo brain" suggesting a potential beneficial role for anti-inflammatory drugs in cancer patients undergoing chemotherapy. We investigated whether the non-steroidal anti-inflammatory drug naproxen influenced hippocampal inflammation in non-tumor bearing female mice receiving the chemotherapy drug cyclophosphamide (CP).Materials and methods: Intact and ovariectomized C57BL/6 mice were used to examine potential role of ovarian hormones on neuroinflammation. The mice were placed on naproxen (375 ppm) or control diet, and a week later CP (100 mg/kg; i.p.) was administered every 3 days for 2 weeks. We analyzed hippocampal inflammatory biomarkers, anxiety-like behavior, spatial working memory, exploratory behavior, spontaneous locomotor activity and depression-like behavior.Results: CP produced significant effects on anti-inflammatory but not pro-inflammatory biomarkers. However, CP and naproxen in combination produced significant effects on both pro- and anti- inflammatory biomarkers. Naproxen and ovariectomy individually produced significant effects on pro- and anti-inflammatory biomarkers as well. Working memory and depression-like behavior were not significantly influenced by CP, naproxen or ovariectomy individually although CP and ovariectomy produced significant interaction effects on depression-like behavior. Exploratory behavior and locomotor activity showed significant effects of CP, and interaction between CP and naproxen was significant for locomotor activity.Conclusions: Ovariectomy, naproxen and a combination of CP and naproxen upregulate hippocampal pro- and anti- inflammatory biomarkers. None of the factors individually produce significant behavioral changes that could be consistent with chemo brain, although CP and ovariectomy in combination produced significant effects on depression-like behavior, a co-morbidity of chemo brain.

Associations between disrupted functional brain network topology and cognitive impairment in patients with rectal cancer during chemotherapy

Introduction

Cognitive impairment has been identified in patients with non-central nervous system cancer received chemotherapy. Chemotherapy-induced changes in the brain are considered as the possible causes of the cognitive deficits of patients. This study aimed to explore chemotherapy-related functional brain changes and cognitive impairment in rectal cancer (RC) patients who had just finished chemotherapy treatment.

Methods

In this study, RC patients after chemotherapy (on the day patients received the last dose of chemotherapy) (n=30) and matched healthy controls (HCs) (n=30) underwent cognitive assessments, structural magnetic resonance imaging (MRI) and resting-state functional MRI. The functional brain networks were constructed by thresholding the partial correlation matrices of 90 brain regions in the Anatomical Automatic Labeling template and the topologic properties were evaluated by graph theory analysis. Moreover, correlations between altered topological measures and scores of cognitive scales were explored in the patient group.

Results

Compared with HCs, RC patients had lower scores of cognitive scales. The functional brain network had preserved small-world topological features but with a tendency towards higher path length in the whole network. In addition, patients had decreased nodal global efficiency (E_glo(i)) in the left superior frontal gyrus (dorsolateral), superior frontal gyrus (orbital part), inferior frontal gyrus (opercular part), inferior frontal gyrus (triangular part) and right inferior frontal gyrus (triangular part). Moreover, values of E_glo(i) in the superior and inferior frontal gyrus were positively associated with cognitive function in the patient group.

Conclusion

These results suggested that cognitive impairment was associated with disruptions of the topological organization in functional brain networks of RC patients who had just finished chemotherapy, which provided new insights into the pathophysiology underlying acute effects of chemotherapy on cognitive function.

Episodic Memory and Recollection Network Disruptions Following Chemotherapy Treatment in Breast Cancer Survivors: A Review of Neuroimaging Findings

Long-term memory disturbances are amongst the most common and disruptive cognitive symptoms experienced by breast cancer survivors following chemotherapy. To date, most clinical assessments of long-term memory dysfunction in breast cancer survivors have utilized basic verbal and visual memory tasks that do not capture the complexities of everyday event memories. Complex event memories, including episodic memory and autobiographical memory, critically rely on hippocampal processing for encoding and retrieval. Systemic chemotherapy treatments used in breast cancer commonly cause neurotoxicity within the hippocampus, thereby creating a vulnerability to memory impairment. We review structural and functional neuroimaging studies that have identified disruptions in the recollection network and related episodic memory impairments in chemotherapy-treated breast cancer survivors, and argue for the need to better characterize hippocampally mediated memory dysfunction following chemotherapy treatments. Given the importance of autobiographical memory for a person's sense of identity, ability to plan for the future, and general functioning, under-appreciation of how this type of memory is impacted by cancer treatment can lead to overlooking or minimizing the negative experiences of breast cancer survivors, and neglecting a cognitive domain that may benefit from intervention strategies.

Clinical and genetic factors associated with self-reported cognitive deficits in women with breast cancer: the "CAGE-Cog" study

Background

Breast cancer patients undergoing chemotherapy treatment are at particular risk of experiencing acute cognitive impairment leading to daily challenges in decision-making and reduced quality of life and functional autonomy. The aim was to assess the relationship between clinical and genetic factors and cognitive function in a sample of patients with breast cancer undergoing chemotherapy.

Methods

A cross-sectional study was carried out between November 2017 and June 2019 on women (N = 112) treated for breast cancer by intravenous chemotherapy at the oncology outpatient unit of Hôtel-Dieu de France Hospital, Beirut. Patients were evaluated with the 37-item Functional Assessment of Cancer Therapy-Cognitive Function (FACT-Cog). Other validated scales were also used to assess depression, anxiety, sleep disorders, pain, and fatigue. DNA was obtained by a buccal swab (FTA®technology) for genotyping of different genes (ABCB1, COMT, DRD2, OPRM1, CLOCK, CRY2, and PER2) using the Lightcycler®(Roche).

Results

The mean age of participants was 56.04 years. Multivariable analysis, taking the four FACT-Cog subscores as the dependent variables, showed that the mean cognitive score decreased with higher depression, anxiety, and insomnia scores. Patients with university education levels had better perceived cognitive abilities than those with primary education. Moreover, carrying the G allele for the OPRM1 polymorphism (c.118A > G;rs197791) was significantly associated with a better cognitive function compared to AA patients (B = 2.05; p = 0.038).

Conclusions

A comprehensive oncological care plan should include a personalized assessment of all factors related to cognitive functioning in cancer patients, particularly anxiety and depression, to achieve an optimal patient outcome.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-022-10077-6.

Infusion of etoposide in the CA1 disrupts hippocampal immediate early gene expression and hippocampus-dependent learning

Tight regulation of immediate early gene (IEG) expression is important for synaptic plasticity, learning, and memory. Recent work has suggested that DNA double strand breaks (DSBs) may have an adaptive role in post-mitotic cells to induce IEG expression. Physiological activity in cultured neurons as well as behavioral training leads to increased DSBs and subsequent IEG expression. Additionally, infusion of etoposide-a common cancer treatment that induces DSBs-impairs trace fear memory. Here, we assessed the effects of hippocampal infusion of 60 ng of etoposide on IEG expression, learning, and memory in 3-4 month-old C57Bl/6J mice. Etoposide altered expression of the immediate early genes cFos and Arc in the hippocampus and impaired hippocampus-dependent contextual fear memory. These data add to the growing evidence that DSBs play an important role in IEG expression, learning, and memory, opening avenues for developing novel treatment strategies for memory-related disorders.

Recovery from the damage of cranial radiation modulated by memantine, an NMDA receptor antagonist, combined with hyperbaric oxygen therapy

BACKGROUND

Radiotherapy is an important treatment option for central nervous system malignancies. However, cranial radiation induces hippocampal dysfunction and white matter injury; this leads to cognitive dysfunction, and results in a reduced quality of life in patients. Excitatory glutamate signaling through N-methyl-d-aspartate receptors (NMDARs) plays a central role both in hippocampal neurogenesis and in the myelination of oligodendrocytes in the cerebrum.

METHODS

We provide a method for quantifying neurogenesis in human subjects in live brain during cancer therapy. Neuroimaging using originally created behavioral tasks was employed to examine human hippocampal memory pathway in patients with brain disorders.

RESULTS

Treatment with memantine, a non-competitive NMDAR antagonist, reversed impairment in hippocampal pattern separation networks as detected by functional magnetic resonance imaging. Hyperbaric preconditioning of the patients just before radiotherapy with memantine mostly reversed white matter injury as detected by whole brain analysis with Tract-Based Spatial Statics. Neuromodulation combined with the administration of hyperbaric oxygen therapy and memantine during radiotherapy facilitated the restoration of hippocampal function and white matter integrity, and improved higher cognitive function in patients receiving cranial radiation.

CONCLUSIONS

The method described herein, for diagnosis of hippocampal dysfunction, and therapeutic intervention can be utilized to restore some of the cognitive decline experienced by patients who have received cranial radiation. The underlying mechanism of restoration is the production of new neurons, which enhances functionality in pattern separation networks in the hippocampi, resulting in an increase in cognitive score, and restoration of microstructural integrity of white matter tracts revealed by Tract-Based Spatial Statics Analysis.

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.

Topological Abnormalities of Pallido-Thalamo-Cortical Circuit in Functional Brain Network of Patients With Nonchemotherapy With Non-small Cell Lung Cancer

INTRODUCTION

Some previous studies in patients with lung cancer have mainly focused on exploring the cognitive dysfunction and deficits of brain function associated with chemotherapy. However, little is known about functional brain alterations that might occur prior to chemotherapy. Therefore, this study aimed to evaluate brain functional changes in patients with nonchemotherapy before chemotherapy with non-small cell lung cancer (NSCLC).

METHODS

Resting-state functional MRI data of 35 patients with NSCLC and 46 matched healthy controls (HCs) were acquired to construct functional brain networks. Graph theoretical analysis was then applied to investigate the differences of the network and nodal measures between groups. Finally, the receiver operating characteristic (ROC) curve analysis was performed to distinguish between NSCLC and HC.

RESULTS

Decreased nodal strength was found in the left inferior frontal gyrus (opercular part), inferior frontal gyrus (triangular part), inferior occipital gyrus, and right inferior frontal gyrus (triangular part) of patients with NSCLC while increased nodal strength was found in the right pallidum and thalamus. NSCLC also showed decreased nodal betweenness in the right superior occipital gyrus. Different hub regions distribution was found between groups, however, no hub regions showed group differences in the nodal measures. Furthermore, the ROC curve analysis showed good performance in distinguishing NSCLC from HC.

CONCLUSION

These results suggested that topological abnormalities of pallido-thalamo-cortical circuit in functional brain network might be related to NSCLC prior to chemotherapy, which provided new insights concerning the pathophysiological mechanisms of NSCLC and could serve as promising biological markers for the identification of patients with NSCLC.

Common cancer treatments targeting DNA double strand breaks affect long-term memory and relate to immediate early gene expression in a sex-dependent manner

DNA double strand breaks (DSBs) have been highly studied in the context of cancers, as DSBs can lead to apoptosis or tumorigenesis. Several pharmaceuticals are widely used to target DSBs during cancer therapy. Amifostine (WR-2721) and etoposide are two commonly used drugs: amifostine reduces DSBs, whereas etoposide increases DSBs. Recently, a novel role for DSBs in immediate early gene expression, learning, and memory has been suggested. Neither amifostine nor etoposide have been assessed for their effects on learning and memory without confounding factors. Moreover, sex-dependent effects of these drugs have not been reported. We administered amifostine or etoposide to 3-4-month-old male and female C57Bl/6J mice before or after training in fear conditioning and assessed learning, memory, and immediate early genes. We observed sex-dependent baseline and drug-induced differences, with females expressing higher cFos and FosB levels than males. These were affected by both amifostine and etoposide. Post-training injections of amifostine affected long-term contextual fear memory; etoposide affected contextual and cued fear memory. These data support the hypothesis that DSBs contribute to learning and memory, and that these could play a part in cognitive side effects during common treatment regimens. The sex-dependent effects also highlight an important factor when considering treatment plans.

Chemotherapy-Induced Cognitive Impairment and Hippocampal Neurogenesis: A Review of Physiological Mechanisms and Interventions

A wide range of cognitive deficits, including memory loss associated with hippocampal dysfunction, have been widely reported in cancer survivors who received chemotherapy. Changes in both white matter and gray matter volume have been observed following chemotherapy treatment, with reduced volume in the medial temporal lobe thought to be due in part to reductions in hippocampal neurogenesis. Pre-clinical rodent models confirm that common chemotherapeutic agents used to treat various forms of non-CNS cancers reduce rates of hippocampal neurogenesis and impair performance on hippocampally-mediated learning and memory tasks. We review the pre-clinical rodent literature to identify how various chemotherapeutic drugs affect hippocampal neurogenesis and induce cognitive impairment. We also review factors such as physical exercise and environmental stimulation that may protect against chemotherapy-induced neurogenic suppression and hippocampal neurotoxicity. Finally, we review pharmacological interventions that target the hippocampus and are designed to prevent or reduce the cognitive and neurotoxic side effects of chemotherapy.

Amifostine (WR-2721) Mitigates Cognitive Injury Induced by Heavy Ion Radiation in Male Mice and Alters Behavior and Brain Connectivity

The deep space environment contains many risks to astronauts during space missions, such as galactic cosmic rays (GCRs) comprised of naturally occurring heavy ions. Heavy ion radiation is increasingly being used in cancer therapy, including novel regimens involving carbon therapy. Previous investigations involving simulated space radiation have indicated a host of detrimental cognitive and behavioral effects. Therefore, there is an increasing need to counteract these deleterious effects of heavy ion radiation. Here, we assessed the ability of amifostine to mitigate cognitive injury induced by simulated GCRs in C57Bl/6J male and female mice. Six-month-old mice received an intraperitoneal injection of saline, 107 mg/kg, or 214 mg/kg of amifostine 1 h prior to exposure to a simplified five-ion radiation (protons, 28Si, 4He, 16O, and 56Fe) at 500 mGy or sham radiation. Mice were behaviorally tested 2-3 months later. Male mice that received saline and radiation exposure failed to show novel object recognition, which was reversed by both doses of amifostine. Conversely, female mice that received saline and radiation exposure displayed intact object recognition, but those that received amifostine prior to radiation did not. Amifostine and radiation also had distinct effects on males and females in the open field, with amifostine affecting distance moved over time in both sexes, and radiation affecting time spent in the center in females only. Whole-brain analysis of cFos immunoreactivity in male mice indicated that amifostine and radiation altered regional connectivity in areas involved in novel object recognition. These data support that amifostine has potential as a countermeasure against cognitive injury following proton and heavy ion irradiation in males.

Effect of chemotherapy and radiotherapy on cognitive impairment in colorectal cancer: evidence from national representative longitudinal database

Objectives

We aimed to assess the risk of chemotherapy- and radiotherapy-related cognitive impairment in colorectal cancer patients.

Methods

Medical use data of colorectal cancer patients were obtained from Korean National Health Insurance Database (NHID), 2004-2018. We randomly selected 40% of colorectal cancer patients (N=148,848). Cognitive impairment cases were defined as having one or more ICD-10 diagnostic codes for dementia or mild cognitive impairment. Patients aged 18 or younger, patients diagnosed with cognitive impairment before colorectal cancer diagnosis (N=8,225) and those who did not receive primary resection (N=45,320) were excluded. The effects of each chemotherapy regimen on cognitive impairment were estimated. We additionally estimated the effect of radiotherapy in rectal cancer patients. Time-dependent competing risk Cox regression was conducted to estimate overall and age-specific hazard ratios (HR) separately for colon and rectal cancer. Landmark analyses with different lag times were conducted as sensitivity analyses.

Results

Chemotherapy did not increase the risk of cognitive impairment in colorectal cancer (colon cancer: HR=0.92, 95% CI 0.83-1.03; rectal cancer: HR=0.88, 95% CI 0.75-1.04). Radiotherapy was negatively associated with cognitive impairment in rectal cancer (HR=0.01, 95% CI 0.84-0.99). Heterogeneous direction of association by regimen combination was detected. Adverse cognitive effect of certain chemotherapy regimen was more prominent in elderly patients.

Conclusion

Chemotherapy and radiotherapy did not increase the risk of cognitive impairment. Elderly patients with low cognitive reserve could be affected by adverse cognitive effects of chemotherapy. Folate administration showed protective effect against possible cognitive impairment.

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.

Memantine Protects against Paclitaxel-Induced Cognitive Impairment through Modulation of Neurogenesis and Inflammation in Mice

Chemotherapy-induced cognitive impairment (CICI) is an adverse side effect of cancer treatment with increasing awareness. Hippocampal damage and related neurocognitive impairment may mediate the development of CICI, in which altered neurogenesis may play a role. In addition, increased inflammation may be related to chemotherapy-induced hippocampal damage. Memantine, an uncompetitive N-methyl-D-aspartate (NMDA) receptor antagonist that may enhance neurogenesis and modulate inflammation, may be useful for treating CICI. To test this hypothesis, paclitaxel was administered to eight-week-old male B6 mice to demonstrate the relationship between CICI and impaired neurogenesis, and then, we evaluated the impact of different memantine regimens on neurogenesis and inflammation in this CICI model. The results demonstrated that both the pretreatment and cotreatment regimens with memantine successfully reversed impaired neurogenesis and spatial memory impairment in behavior tests. The pretreatment regimen unsuccessfully inhibited the expression of peripheral and central TNF-α and IL-1β and did not improve the mood alterations following paclitaxel treatment. However, the cotreatment regimen led to a better modulatory effect on inflammation and restoration of mood disturbance. In conclusion, this study illustrated that impaired neurogenesis is one of the mechanisms of paclitaxel-induced CICI. Memantine may serve as a potential treatment for paclitaxel-induced CICI, but different treatment strategies may lead to variations in the treatment efficacy.

Donepezil Protects Against Doxorubicin-Induced Chemobrain in Rats via Attenuation of Inflammation and Oxidative Stress Without Interfering With Doxorubicin Efficacy

Although doxorubicin (Dox) is an effective chemotherapy medication used extensively in the treatment of breast cancer, it frequently causes debilitating neurological deficits known as chemobrain. Donepezil (DPZ), an acetylcholinesterase inhibitor, provides therapeutic benefits in various neuropathological conditions. However, comprehensive mechanistic insights regarding the neuroprotection of DPZ on cognition and brain pathologies in a Dox-induced chemobrain model remain obscure. Here, we demonstrated that Dox-treated rats manifested conspicuous cognitive deficits and developed chemobrain pathologies as indicated by brain inflammatory and oxidative insults, glial activation, defective mitochondrial homeostasis, increased potential lesions associated with Alzheimer's disease, disrupted neurogenesis, loss of dendritic spines, and ultimately neuronal death through both apoptosis and necroptosis. Intervention with DPZ co-treatment completely restored cognitive function by attenuating these pathological conditions induced by DOX. We also confirmed that DPZ treatment does not affect the anti-cancer efficacy of Dox in breast cancer cells. Together, our findings suggest that DPZ treatment confers potential neuroprotection against Dox-induced chemobrain.

Methotrexate Neurotoxicity Is Related to Epigenetic Modification of the Myelination Process

With the improvement of the survival rate of acute lymphoblastic leukemia (ALL) in children, some children ALL survivors reveal inferior intellectual and cognition outcome. Methotrexate (MTX), while serving as an essential component in ALL treatment, has been reported to be related to various neurologic sequelae. Using combined intrathecal (IT) and intraperitoneal (IP) MTX model, we had demonstrated impaired spatial memory function in developing rats, which can be rescued by melatonin treatment. To elucidate the impact of MTX treatment on the epigenetic modifications of the myelination process, we examined the change of neurotrophin and myelination-related transcriptomes in the present study and found combined IT and IP MTX treatment resulted in altered epigenetic modification on the myelination process, mainly in the hippocampus. Further, melatonin can restore the MTX effect through alterations of the epigenetic pathways.

Oroxylum Indicum ameliorates chemotherapy induced cognitive impairment

While chemotherapy is the most effective therapeutic approach for treating a variety of cancer patients, commonly used chemotherapeutic agents, often induce several adverse effects. Escalating evidence indicates that chemotherapeutics, particularly doxorubicin (DOX) and cyclophosphamide (CPS), induce cognitive impairment associated with central nervous system toxicity. This study was performed to determine neuroprotective effects of Oroxylum indicum extract (OIE) in regard to preventing chemotherapy induced cognitive impairment (CICI) occurring after 4 cycles of DOX (2mg/kg) and CPS (50mg/kg) combination chemotherapy in male C57BL/6J mice. OIE significantly prevented the chemotherapy impaired short-term cognitive performance, exploratory behavior associated with cognitive performance, cognitive performance, and spatial learning and memory in the Y-maze, Open-Field, Novel Object Recognition, and Morris Water Maze tests, respectively. These data suggest that OIE protects from the CICI. OIE decreased the reactive oxygen species and lipid peroxide generated by the chemotherapy treatment in the brain, while also blocking the chemotherapy-induced glutathione depletion. These results establish that OIE exhibits potent antioxidant activity in chemotherapy treated mice. Notably, OIE significantly increased the Complex-I and Complex-IV activities in the brain, indicating that OIE enhances mitochondrial function in the brain. In silico analysis of the major active chemical constituents (Oroxylin A, Baicalein and Chrysin) of OIE indicated that OIE has a favorable absorption, distribution, metabolism and excretion (ADME) profile. Taken together, our results are consistent with the conclusion that OIE prevents CICI by counteracting oxidative stress and perhaps by improving mitochondrial function.

Early Effects of Cyclophosphamide, Methotrexate, and 5-Fluorouracil on Neuronal Morphology and Hippocampal-Dependent Behavior in a Murine Model

Breast cancer (BC) is the most common cancer among women. Fortunately, BC survival rates have increased because the implementation of adjuvant chemotherapy leading to a growing population of survivors. However, chemotherapy-induced cognitive impairments (CICIs) affect up to 75% of BC survivors and may be driven by inflammation and oxidative stress. Chemotherapy-induced cognitive impairments can persist 20 years and hinder survivors' quality of life. To identify early effects of CMF administration in mice, we chose to evaluate adult female mice at 2-week postchemotherapy. Mice received weekly IP administration of CMF (or saline) for 4 weeks, completed behavioral testing, and were sacrificed 2 weeks following their final CMF injection. Behavioral results indicated long-term memory (LTM) impairments postchemotherapy, but did not reveal short-term memory deficits. Dendritic morphology and spine data found increases in overall spine density within CA1 basal and CA3 basal dendrites, but no changes in DG, CA1 apical, or CA3 apical dendrites. Further analysis revealed decreases in arborization across the hippocampus (DG, CA1 apical and basal, CA3 apical and basal). These physiological changes within the hippocampus correlate with our behavioral data indicating LTM impairments following CMF administration in female mice 2-week postchemotherapy. Hippocampal cytokine analysis identified decreases in IL-1α, IL-1β, IL-3, IL-10, and TNF-α levels.

Brain Microstructural Changes Associated With Neurocognitive Outcome in Intracranial Germ Cell Tumor Survivors

Background

Childhood intracranial germ cell tumor (GCT) survivors are prone to radiotherapy-related neurotoxicity, which can lead to neurocognitive dysfunctions. Diffusion kurtosis imaging (DKI) is a diffusion MRI technique that is sensitive to brain microstructural changes. This study aimed to investigate the association between DKI metrics versus cognitive and functional outcomes of childhood intracranial GCT survivors.

Methods

DKI was performed on childhood intracranial GCT survivors (n = 20) who had received cranial radiotherapy, and age and gender-matched healthy control subjects (n = 14). Neurocognitive assessment was performed using the Hong Kong Wechsler Intelligence Scales, and functional assessment was performed using the Lansky/Karnofsky performance scales (KPS). Survivors and healthy controls were compared using mixed effects model. Multiple regression analyses were performed to determine the effects of microstructural brain changes of the whole brain as well as the association between IQ and Karnofsky scores and the thereof.

Results

The mean Intelligence Quotient (IQ) of GCT survivors was 91.7 (95% CI 84.5 – 98.8), which was below the age-specific normative expected mean IQ (P = 0.013). The mean KPS score of GCT survivors was 85.5, which was significantly lower than that of controls (P < 0.001). Cognitive impairments were significantly associated with the presence of microstructural changes in white and grey matter, whereas functional impairments were mostly associated with microstructural changes in white matter. There were significant correlations between IQ versus the mean diffusivity (MD) and mean kurtosis (MK) of specific white matter regions. The IQ scores were negatively correlated with the MD of extensive grey matter regions.

Conclusion

Our study identified vulnerable brain regions whose microstructural changes in white and grey matter were significantly associated with impaired cognitive and physical functioning in survivors of pediatric intracranial GCT.

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 complications of cancer and cancer-related treatments - Novel paradigms

As advances in diagnostics and therapeutic strategies in oncology have increased the number of cancer survivors, the investigation of the mechanisms associated with long-term cognitive complications of cancer treatment has become an important topic of interest. The neurotoxic effects of chemotherapeutic agents have been described in pre-clinical and clinical research. In vitro and rodent studies have identified some underlying mechanisms contributing to chemotherapy-induced neurotoxicity and cognitive impairment for various chemotherapy drugs and other cancer treatments. However, investigation of the direct biological effects of cancer and other potential contributing factors in the pathogenesis of cancer-related cognitive impairment (CRCI) has only recently come into focus. This review will highlight evidence from pre-clinical tumor-bearing rodent models suggesting that cancer influences the cognitive and behavioral changes reported in human cancer populations through direct or indirect pathways that alter the normal neuroinflammatory responses, induce structural brain deficits, and decrease neurogenesis. We reflect on human clinical cancer research indicating that cognitive and behavioral changes precede cancer treatment in some malignancies. We also highlight implications for future areas of CRCI research based on novel findings on the interplay between cancer, chemotherapy, inflammation, tau pathology, and dysregulation of the microbiota-gut-brain axis.

First extensive study of silver-doped lanthanum manganite nanoparticles for inducing selective chemotherapy and radio-toxicity enhancement

Nanoparticles have a great potential to increase the therapeutic efficiency of several cancer therapies. This research examines the potential for silver-doped lanthanum manganite nanoparticles to enhance radiation therapy to target radioresistant brain cancer cells, and their potential in combinational therapy with magnetic hyperthermia. Magnetic and structural characterisation found all dopings of nanoparticles (NPs) to be pure and single phase with an average crystallite size of approximately 15 nm for undoped NPs and 20 nm for silver doped NPs. Additionally, neutron diffraction reveals that La_0.9Ag_0.1MnO₃ (10%-LAGMO) NPs exhibit residual ferromagnetism at 300 K that is not present in lower doped NPs studied in this work, indicating that the Curie temperature may be manipulated according to silver doping. This radiobiological study reveals a completely cancer-cell selective treatment for LaMnO₃, La_0.975Ag_0.025MnO₃ and La_0.95Ag_0.05MnO₃ (0, 2.5 and 5%-LAGMO) and also uncovers a potent combination of undoped lanthanum manganite with orthovoltage radiation. Cell viability assays and real time imaging results indicated that a concentration of 50 μg/mL of the aforementioned nanoparticles do not affect the growth of Madin-Darby Canine Kidney (MDCK) non-cancerous cells over time, but stimulate its metabolism for overgrowth, while being highly toxic to 9L gliosarcoma (9LGS). This is not the case for 10%-LAGMO nanoparticles, which were toxic to both non-cancerous and cancer cell lines. The nanoparticles also exhibited a level of toxicity that was regulated by the overproduction of free radicals, such as reactive oxygen species, amplified when silver ions are involved. With the aid of fluorescent imaging, the drastic effects of these reactive oxygen species were visualised, where nucleus cleavage (an apoptotic indicator) was identified as a major consequence. The genotoxic response of this effect for 9LGS and MDCK due to 10%-LAGMO NPs indicates that it is also causing DNA double strand breaks within the cell nucleus. Using 125 kVp orthovoltage radiation, in combination with an appropriate amount of NP-induced cell death, identified undoped lanthanum manganite as the most ideal treatment. Real-time imaging following the combination treatment of undoped lanthanum manganite nanoparticles and radiation, highlighted a hinderance of growth for 9LGS, while MDCK growth was boosted. The clonogenic assay following incubation with undoped lanthanum manganite nanoparticles combined with a relatively low dose of radiation (2 Gy) decreased the surviving fraction to an exceptionally low (0.6 ± 6.7)%. To our knowledge, these results present the first biological in-depth analysis on silver-doped lanthanum manganite as a brain cancer selective chemotherapeutic and radiation dose enhancer and as a result will propel its first in vivo investigation.

Peripheral Neuropathy under Oncologic Therapies: A Literature Review on Pathogenetic Mechanisms

Peripheral neurologic complications are frequent adverse events during oncologic treatments and often lead to dose reduction, administration delays with time elongation of the therapeutic plan and, not least, worsening of patients' quality of life. Experience skills are required to recognize symptoms and clinical evidences and the collaboration between different health professionals, in particular oncologists and hospital pharmacists, grants a correct management of this undesirable occurrence. Some classes of drugs (platinates, vinca alkaloids, taxanes) typically develop this kind of side effect, but the genesis of chemotherapy-induced peripheral neuropathy is not linked to a single mechanism. This paper aims from one side at summarizing and explaining all the scattering mechanisms of chemotherapy-induced peripheral neuropathy through a detailed literature revision, on the other side at finding new approaches to possible treatments, in order to facilitate the collaboration between oncologists, hematologists and hospital pharmacists.

A narrative review of risk factors and interventions for cancer-related cognitive impairment

Cancer-related cognitive impairment (CRCI) refers to a series of cognitive impairment symptoms associated with alternations in brain structure and function, caused by a non-central nervous system malignant tumor and its related treatment. CRCI may present as memory loss, impaired concentration, difficulty in multitasking and word retrieval, and reduced comprehension speed. CRCI has become one of the prevalent factors that compromise the quality of life for cancer survivors. Different treatments, including surgery, chemotherapy, radiotherapy, endocrine therapy, and targeted drugs, may contribute to CRCI. Meanwhile, patients’ factors, including emotional challenges and genetic makeup, also contribute to the development of CRCI. The condition can be treated with using stimulants methylphenidate and modafinil, metabolites of nicotine: cotinine, antidepressants of fluoxetine and fluvoxamine, dementia drug of donepezil, and antioxidants ZnSO4, n-acetyl cysteine, propofol, and Chinese herbal of silver leaf medicine. Psychotherapies, including meditation and relaxation, cognitive rehabilitation training, along with physical therapies, including aerobic exercise, resistance training, balance training, yoga, qigong, tai chi electroencephalogram biofeedback, and acupuncture, are also beneficial in alleviating cancer-related cognitive impairment symptoms. In recent years, researchers have focused on factors related to the condition and on the available interventions. However, most research was conducted independently, and no review has yet summarized the latest findings. This review details and discusses the status of related factors and potential treatments for CRCI. We also supply specific recommendations to facilitate future research and integration in this field.

Dehydrozingerone protects temozolomide-induced cognitive impairment in normal and C6 glioma rats besides enhancing its anticancer potential

Considering the cognitive impairment induced by temozolomide (TMZ) in glioblastoma survivors, the present study was aimed to evaluate the protective effect of dehydrozingerone (DHZ) against TMZ-induced cognitive impairment (chemobrain) and C6 cell line-induced glioma in male Wistar rats. In both chemobrain and glioma models, TMZ was administered at a dose of 18 mg/kg i.v every 5th day and DHZ at a dose of 100 mg/kg p.o. daily. Additionally, glioma was induced by intracerebral injection of 5 × 10⁴ C6 rat glioma cells in the cortex in the glioma model. Upon disease induction and treatment with TMZ + DHZ, spatial memory was assessed by the Morris water maze (MWM) test and episodic memory by the novel object recognition test (NORT). The induction of glioma was confirmed by histology of the cortex. Hippocampus and frontal cortex were subjected to antioxidant evaluation. Significant loss of spatial and episodic memory was observed with TMZ treatment which was significantly restored by DHZ. DHZ showed significant improvement in oxidative stress markers reversed the histopathological features in the cortex. TMZ-induced elevation of the glutathione level was also reversed by DHZ, indicating the role of DHZ in the reversal of TMZ resistance. In the glioma model, the improvement in cognition by DHZ correlated with the decrease in tumor volume. Altogether, the study results reveal the role of TMZ in worsening the memory and DHZ in reversing it, besides, improving its anticancer potential.

Neurotoxicity of antineoplastic drugs: Mechanisms, susceptibility, and neuroprotective strategies

This review summarizes the adverse effects on the central and/or peripheral nervous systems that may occur in response to antineoplastic drugs. In particular, we describe the neurotoxic side effects of the most commonly used drugs, such as platinum compounds, doxorubicin, ifosfamide, 5-fluorouracil, vinca alkaloids, taxanes, methotrexate, bortezomib and thalidomide. Neurotoxicity may result from direct action of compounds on the nervous system or from metabolic alterations produced indirectly by these drugs, and either the central nervous system or the peripheral nervous system, or both, may be affected. The incidence and severity of neurotoxicity are principally related to the dose, to the duration of treatment, and to the dose intensity, though other factors, such as age, concurrent pathologies, and genetic predisposition may enhance the occurrence of side effects. To avoid or reduce the onset and severity of these neurotoxic effects, the use of neuroprotective compounds and/or strategies may be helpful, thereby enhancing the therapeutic effectiveness of antineoplastic drug.

Altered Functional Connectivity Density in Young Survivors of Acute Lymphoblastic Leukemia Using Resting-State fMRI

Objective

Using functional connectivity density (FCD) mapping measured by resting-state functional magnetic resonance imaging (rs-fMRI), an ultrafast data-driven graph theory approach, we attempted to study the abnormalities in neural activity of young survivors of acute lymphoblastic leukemia (ALL) and to explore the neuropathological evidence of chemotherapy-related cognitive impairment of patients.

Methods

Twenty young survivors of ALL and 18 well-matched healthy controls (HCs) were recruited in this study. All ALL patients and healthy controls underwent rs-fMRI scans and completed neurocognitive testing. The between-group differences in short-range and long-range FCD were calculated by the option of degree centrality (DC) in MATLAB software after preprocessing. The correlations between the FCD value and each of the neurocognitive outcomes were analyzed in the ALL patients.

Results

The group-averaged FCD maps showed similar spatial patterns between the two groups. Compared with the HCs, ALL patients showed decreased long-range FCD in regions of the bilateral lingual gyrus, cingulate cortex, hippocampal gyrus, and right calcarine fissure. Simultaneously, decreased regions in the short-range FCD map were the bilateral lingual gyrus, cingulate cortex, parahippocampal gyrus and right calcarine fissure. Increased functional connectivity (FC) was observed between the region with decreased long-range FCD and the posterior cerebellar lobe, and decreased FC was observed between the region and the middle occipital gyrus, cuneus and lingual gyrus. Thus, there existed no brain areas with increased FCD. The decreased short-range FCD value of ALL patients was positively correlated with the score on the Digit Span Test (Forward), and the increased FC value was negatively correlated with the score on the Trail Making Test part A.

Conclusion

Our results suggest the altered functional connectivity of young survivors of ALL in the posterior region of the brain and posterior lobe of the cerebellum. Alterations in spontaneous neuronal activity seem to parallel the neurocognitive testing, which indicates that the rs-fMRI could be used as a neuroimaging marker for neurological impairment in ALL patients.

Metformin alleviates memory and hippocampal neurogenesis decline induced by methotrexate chemotherapy in a rat model

Methotrexate (MTX) is a chemotherapeutic drug commonly used to treat cancers that has an adverse effect on patients' cognition. Metformin is a primary treatment for type 2 diabetes mellitus that can pass through the blood-brain barrier. Metformin has neuroprotective actions, which can improve memory. In the present study, we examined the ability of metformin in MTX chemotherapy-generated cognitive and hippocampal neurogenesis alterations. Male Sprague-Dawley rats were allocated into control, MTX, metformin, preventive, and throughout groups. MTX (75 mg/kg/day) was given intravenously on days 7 and 14 of the study. Metformin (200 mg/kg/day) was injected intraperitoneally for 14 days. Some of the MTX-treated rats received co-treatment with metformin once a day for either 14 (preventive) or 28 days (throughout). After treatment, memory ability was evaluated using novel object location and novel object recognition tests. Ki67 (proliferating cells), BrdU (survival cells), and doublecortin (immature neurons, DCX) positive cells in the subgranular zone (SGZ) of the hippocampal dentate gyrus were quantified. We found that reductions of cognition, the number of proliferating and survival cells and immature neurons in the SGZ were ameliorated in the co-treatment groups, which suggests that metformin can prevent memory and hippocampal neurogenesis impairments induced by MTX in adult rats.

Isobaric Labeling Strategy Utilizing 4-Plex N,N-Dimethyl Leucine (DiLeu) Tags Reveals Proteomic Changes Induced by Chemotherapy in Cerebrospinal Fluid of Children with B-Cell Acute Lymphoblastic Leukemia

The use of mass spectrometry for protein identification and quantification in cerebrospinal fluid (CSF) is at the forefront of research efforts to identify and explore biomarkers for the early diagnosis and prognosis of neurologic disorders. Here we implemented a 4-plex N,N-dimethyl leucine (DiLeu) isobaric labeling strategy in a longitudinal study aiming to investigate protein dynamics in children with B-cell acute lymphoblastic leukemia (B-cell ALL) undergoing chemotherapy. The temporal profile of CSF proteome during chemotherapy treatment at weeks 5, 10-14, and 24-28 highlighted many differentially expressed proteins, such as neural cell adhesion molecule, neuronal growth regulator 1, and secretogranin-3, all of which play important roles in neurodegenerative diseases. A total of 63 proteins were significantly altered across all of the time points investigated. The most over-represented biological processes from gene ontology analysis included platelet degranulation, complement activation, cell adhesion, fibrinolysis, neuron projection, regeneration, and regulation of neuron death. We expect that results from this and future studies will provide a means to monitor neurotoxicity and develop strategies to prevent central nervous system injury in response to chemotherapy in children.

Neurodevelopmental Consequences of Pediatric Cancer and Its Treatment: The Role of Sleep

Cognitive impairment is frequent in pediatric cancer, and behavioral and psychological disturbances often also affect children who have survived cancer problems. Furthermore, pediatric tumors are also often associated with sleep disorders. The interrelationship between sleep disorders, neurodevelopmental disorders and pediatric cancer, however, is still largely unexplored. In this narrative review we approach this important aspect by first considering studies on pediatric cancer as a possible cause of neurodevelopmental disorders and then describing pediatric cancer occurring as a comorbid condition in children with neurodevelopmental disorders. Finally, we discuss the role of sleep disorders in children with cancer and neurodevelopmental disorders. Even if the specific literature approaching directly the topic of the role of sleep in the complex relationship between pediatric cancer and neurodevelopmental disorders was found to be scarce, the available evidence supports the idea that in-depth knowledge and correct management of sleep disorders can definitely improve the health and quality of life of children with cancer and of their families.