Chemotherapy-related cognitive dysfunction: current animal studies and future directions

Brain gray matter reduction and premature brain aging after breast cancer chemotherapy: a longitudinal multicenter data pooling analysis

Brain gray matter (GM) reductions have been reported after breast cancer chemotherapy, typically in small and/or cross-sectional cohorts, most commonly using voxel-based morphometry (VBM). There has been little examination of approaches such as deformation-based morphometry (DBM), machine-learning-based brain aging metrics, or the relationship of clinical and demographic risk factors to GM reduction. This international data pooling study begins to address these questions. Participants included breast cancer patients treated with (CT+, n = 183) and without (CT-, n = 155) chemotherapy and noncancer controls (NC, n = 145), scanned pre- and post-chemotherapy or comparable intervals. VBM and DBM examined GM volume. Estimated brain aging was compared to chronological aging. Correlation analyses examined associations between VBM, DBM, and brain age, and between neuroimaging outcomes, baseline age, and time since chemotherapy completion. CT+ showed longitudinal GM volume reductions, primarily in frontal regions, with a broader spatial extent on DBM than VBM. CT- showed smaller clusters of GM reduction using both methods. Predicted brain aging was significantly greater in CT+ than NC, and older baseline age correlated with greater brain aging. Time since chemotherapy negatively correlated with brain aging and annual GM loss. This large-scale data pooling analysis confirmed findings of frontal lobe GM reduction after breast cancer chemotherapy. Milder changes were evident in patients not receiving chemotherapy. CT+ also demonstrated premature brain aging relative to NC, particularly at older age, but showed evidence for at least partial GM recovery over time. When validated in future studies, such knowledge could assist in weighing the risks and benefits of treatment strategies.

Neuroprotective effect of lansoprazole against cisplatin-induced brain toxicity: Role of Nrf2/ARE and Akt/P53 signaling pathways

Cisplatin is a chemotherapeutic agent usually used in treating different patterns of malignancies. One of the significant apparent complications of cisplatin chemotherapy is brain toxicity. The present study was conducted to evaluate the protective effects of lansoprazole on cisplatin-induced cortical intoxication. Thirty-two rats were allocated into four groups (8 rats/group); group I: received only a vehicle for 10 days, group II: lansoprazole was administered (50 mg/kg) via oral gavage for 10 days, group III: On 5th day of the experiment, rats were given cisplatin (10 mg/kg) i.p. once to induce cortical injury. Group IV: rats were given lansoprazole for 5 days before cisplatin and 5 days afterward. Lansoprazole administration significantly improved cisplatin-induced behavioral changes, as evidenced by decreasing the immobility time in forced swimming and open field tests. Besides, lansoprazole improved cortical histological changes, restored cortical redox balance, enhanced Nrf2/ARE expression, cisplatin-induced neuronal apoptosis, and dampened cisplatin inflammation. In addition, lansoprazole modulated cortical Akt/p53 signal. The present work was the first to show that lansoprazole co-administration reduced cortical toxicity in cisplatin-treated rats via multiple signaling pathways. The current findings provided crucial information for developing novel protective strategies to reduce cisplatin cortical toxicity.

Activity in Group-Housed Home Cages of Mice as a Novel Preclinical Biomarker in Oncology Studies

BACKGROUND

Improving experimental conditions in preclinical animal research is a major challenge, both scientifically and ethically. Automated digital ventilated cages (DVC®) offer the advantage of continuous monitoring of animal activity in their home-cage. The potential utility of this technology remains understudied and deserves investigation in the field of oncology.

METHODS

Using the DVC® platform, we sought to determine if the continuous assessment of locomotor activity of mice in their home cages can serve as useful digital readout in the monitoring of animals treated with the reference oncology compounds cisplatin and cyclophosphamide. SCID mice of 14 weeks of age were housed in DVC® cages in groups of four and followed with standard and digital examination before and after treatment over a 17-day total period.

RESULTS

DVC® detected statistically significant effects of cisplatin on the activity of mice in the short and long term, as well as trends for cyclophosphamide. The activity differences between the vehicle- and chemotherapy-treated groups were especially marked during the nighttime, a period when animals are most active and staff are generally not available for regular checks. Standard clinical parameters, such as body weight change and clinical assessment during the day, provided additional and complementary information.

CONCLUSION

The DVC® technology enabled the home cage monitoring of mice and non-invasive detection of animal activity disturbances. It can easily be integrated into a multimodal monitoring approach to better capture the different effects of oncology drugs on anti-tumor efficacy, toxicity, and safety and improve translation to clinical studies.

Neuroimaging based biotypes for precision diagnosis and prognosis in cancer-related cognitive impairment

Cancer related cognitive impairment (CRCI) is commonly associated with cancer and its treatments, yet the present binary diagnostic approach fails to capture the full spectrum of this syndrome. Cognitive function is highly complex and exists on a continuum that is poorly characterized by dichotomous categories. Advanced statistical methodologies applied to symptom assessments have demonstrated that there are multiple subclasses of CRCI. However, studies suggest that relying on symptom assessments alone may fail to account for significant differences in the neural mechanisms that underlie a specific cognitive phenotype. Treatment plans that address the specific physiologic mechanisms involved in an individual patient's condition is the heart of precision medicine. In this narrative review, we discuss how biotyping, a precision medicine framework being utilized in other mental disorders, could be applied to CRCI. Specifically, we discuss how neuroimaging can be used to determine biotypes of CRCI, which allow for increased precision in prediction and diagnosis of CRCI via biologic mechanistic data. Biotypes may also provide more precise clinical endpoints for intervention trials. Biotyping could be made more feasible with proxy imaging technologies or liquid biomarkers. Large cross-sectional phenotyping studies are needed in addition to evaluation of longitudinal trajectories, and data sharing/pooling is highly feasible with currently available digital infrastructures.

Neurocognitive test performance following cancer among middle-aged and older adults in the Hispanic Community Health Study/Study of Latinos (HCHS/SOL) and the SOL-Investigation of Neurocognitive Aging Ancillary Study

BACKGROUND

Cancer patients and survivors often experience acute cognitive impairments; however, the long-term cognitive impact remains unclear particularly among Hispanics/Latinos. We examined the association between cancer history and neurocognitive test performance among middle-aged and older Hispanic/Latinos.

METHODS

Participants included 9639 Hispanic/Latino adults from the community-based and prospective Hispanic Community Health Study/Study of Latinos. At baseline (2008-2011; V1), participants self-reported their cancer history. At V1 and again at a 7-year follow-up (2015-2018; V2), trained technicians administered neurocognitive tests including the Brief-Spanish English Verbal Learning Test (B-SEVLT), Word Fluency Test (WF), and Digit Symbol Substitution Test (DSS). We used survey linear regression to estimate the overall, sex-specific, and cancer site-specific [i.e., cervix, breast, uterus, and prostate] adjusted associations between cancer history and neurocognitive test performance at V1 and changes from V1 to V2.

RESULTS

At V1, a history of cancer (6.4%) versus no history of cancer (93.6%) was associated with higher WF scores (β = 0.14, SE = 0.06; p = 0.03) and global cognition (β = 0.09, SE = 0.04; p = 0.04). Among women, a history of cervical cancer predicted decreases in SEVLT-Recall scores (β = -0.31, SE = 0.13; p = 0.02) from V1 to V2, and among men, a history of prostate cancer was associated with higher V1 WF scores (β = 0.29, SE = 0.12; p = 0.02) and predicted increases in SEVLT-Sum (β = 0.46, SE = 0.22; p = 0.04) from V1 to V2.

CONCLUSION

Among women, a history of cervical cancer was associated with 7-year memory decline, which may reflect the impacts of systemic cancer therapies. Among men, however, a history of prostate cancer was associated with improvements in cognitive performance, perhaps due in part to engaging in health promoting behaviors following cancer.

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.

Diagnostic Accuracy of Machine-Learning Models on Predicting Chemo-Brain in Breast Cancer Survivors Previously Treated with Chemotherapy: A Meta-Analysis

We performed a meta-analysis of chemo-brain diagnostic, pooling sensitivities, and specificities in order to assess the accuracy of a machine-learning (ML) algorithm in breast cancer survivors previously treated with chemotherapy. We searched PubMed, Web of Science, and Scopus for eligible articles before 30 September 2022. We identified three eligible studies from which we extracted seven ML algorithms. For our data, the χ² tests demonstrated the homogeneity of the sensitivity's models (χ² = 7.6987, df = 6, p-value = 0.261) and the specificities of the ML models (χ² = 3.0151, df = 6, p-value = 0.807). The pooled area under the curve (AUC) for the overall ML models in this study was 0.914 (95%CI: 0.891-0.939) and partial AUC (restricted to observed false positive rates and normalized) was 0.844 (95%CI: 0.80-0.889). Additionally, the pooled sensitivity and pooled specificity values were 0.81 (95% CI: 0.75-0.86) and 0.82 (95% CI: 0.76-0.86), respectively. From all included ML models, support vector machine demonstrated the best test performance. ML models represent a promising, reliable modality for chemo-brain prediction in breast cancer survivors previously treated with chemotherapy, demonstrating high accuracy.

Cerebral glucose changes after chemotherapy and their relation to long-term cognitive complaints and fatigue

Purpose

To investigate the short-term cerebral metabolic effects of intravenous chemotherapy and their association with long-term fatigue/cognitive complaints.

Experimental design

Using [¹⁸F]-FDG-PET/CT whole-body scans, we retrospectively quantified relative cerebral glucose metabolism before and after neoadjuvant chemotherapy in a cohort of patients treated for non-metastatic breast cancer (2009-2019). Self-report of cognitive complaints and fatigue were prospectively assessed 7 ± 3 years after therapy. Metabolic changes were estimated with i) robust mixed-effects modelling in regions-of-interest (frontal, parietal, temporal, occipital, and insular cortex) and ii) general-linear modelling of whole-brain voxel-wise outcomes. iii) The association between metabolic changes and self-reported outcomes was evaluated using linear regression-analysis.

Results

Of the 667 screened patients, 263 underwent PET/CT before and after chemotherapy and 183 (48 ± 9 years) met the inclusion criteria. After chemotherapy, decreased frontal and increased parietal and insular metabolism were observed (|ß|>0.273, p_FDR<0.008). Separately, additional increased occipital metabolism after epiribucin+ cyclophosphamide (EC) and temporal metabolism after EC+ fluorouracil chemotherapy were observed (ß>0.244, p_FDR≤0.048). Voxel-based analysis (p_cluster-FWE<0.001) showed decreased metabolism in the paracingulate gyrus (-3.2 ± 3.9%) and putamen (3.1 ± 4.1%) and increased metabolism in the lateral cortex (L=2.9 ± 3.1%) and pericentral gyri (3.0 ± 4.4%). Except for the central sulcus, the same regions showed changes in EC, but not in FEC patients. Of the 97 self-reported responders, 23% and 27% experienced extreme fatigue and long-term cognitive complaints, respectively, which were not associated with metabolic changes.

Conclusion

Both hyper- and hypometabolism were observed after chemotherapy for breast cancer. Combined with earlier findings, this study could support inflammatory mechanisms resulting in relative hypermetabolism, mainly in the parietal/occipital cortices. As early metabolic changes did not precede long-term complaints, further research is necessary to identify vulnerable patients.

Evaluation of the Effects of R-CHOP Chemotherapy on Brain Glucose Metabolism in Patients with Diffuse Large B Cell Lymphoma: A Baseline, Interim, and End-of-Treatment PET/CT Study

BACKGROUND

To investigate the effect of rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) chemotherapy on brain glucose metabolism in patients with diffuse large B cell lymphoma (DLBCL).

METHODS

Seventy-two patients with newly diagnosed DLBCL underwent FDG PET/CT brain and whole-body scans at baseline (PET0), in the interim of chemotherapy (PET2), and at the end (PET6) of chemotherapy. All three brain scans of each patient were analyzed using statistical parametric mapping software.

RESULTS

Compared with the PET0 scan, the PET2 and PET6 scans revealed a significantly higher glucose metabolism throughout the whole brain, with the PET6 scan revealing a higher metabolism than the PET2 scan. Patients with a complete response (CR) displayed decreased glucose metabolism in the lingual gyrus and increased glucose metabolism in the pons after chemotherapy compared with the findings in patients with partial responses or progressive disease.

CONCLUSIONS

Brain glucose metabolism was affected by R-CHOP treatment throughout the entire chemotherapy protocol.

Cognitive impairment and elevated peripheral cytokines in breast cancer patients receiving chemotherapy

BACKGROUND

Anthracyclines-based regimen (5-fluorouracil, doxorubicin, and cyclophosphamide (FAC); cyclophosphamide, epirubicin, and 5-fluorouracil [CEF]) and non-anthracycline based regimens (cyclophosphamide, methotrexate, and 5-fluorouracil [CMF]) are widely used as neoadjuvant chemotherapy for breast cancer patients.

OBJECTIVE

The present study was conducted to observe the effects of FAC, CEF, and CMF regimen on cognition and circulatory proinflammatory cytokines (interleukin 6 [IL-6] and interleukin 1β [IL-1β]) for the duration of three cycles of chemotherapy in breast cancer patients.

METHODS

Eighty newly diagnosed HER-2 negative breast cancer patients were enrolled and divided into 3 groups as FAC- (n = 27), CEF- (n = 26), and CMF- (n = 27) receiving patients. Serum IL-6 and IL-1β levels were measured by using enzyme-linked immunosorbent assay (ELISA), and cognition was assessed using the Mini-Mental State examination (MMSE) questionnaire.

RESULTS

Anthracycline-based regimen was found to increase the levels of IL-6, IL-1β, and decreased MMSE scores compared with CMF regimen (p < 0.05).

CONCLUSION

Anthracycline-based regimen caused comparatively higher peripheral inflammation, which could be the reason for more decline in cognition in anthracycline-receiving patients than non-anthracycline group.

Anticancer and Neuroprotective Activities of Ethyl Acetate Fractions from Morus macroura Miq. Plant Organs with Ultraperformance Liquid Chromatography-Electrospray Ionization-Tandem Mass Spectrometry Profiling

Column chromatography afforded the isolation of seven secondary metabolites (1-(2,4,6-trihydroxy phenyl)-ethanone-4-O-β-d-glucopyranoside, naringenin-7-O-β-d-glucopyranoside, kaempferol-3-O-α-l-rhamnoside, kaempferol-3-O-β-d-glucopyranoside, quercetin-3-O-β-d-glucopyranoside, quercetin-3-O-β-d-galactopyranoside, rutin) from the ethyl acetate (ET) fractions of Morus macroura Miq. stems (S), leaves (L), and fruits (F). Their identification based on ultraviolet (UV), electron ionization (EI), electrospray ionization-mass spectrometry (ESI-MS), and 1D and 2D NMR data. In addition, profiling of ET fractions using ultraperformance liquid chromatography-electrospray ionization-tandem mass spectrometry (UPLC-ESI-MS/MS) resulted in the identification of 82 compounds belonging to different classes, mainly polyphenolic constituents. Chemical profiling as well as molecular docking directed us to biological evaluation. Interestingly, the ET-L fraction exhibited a robust cytotoxic activity against HepG-2, MCF-7, and HELA cell lines. Also, it displayed a neuromodulatory activity against cisplatin neurotoxicity in rats by ameliorating the neurobehavioral dysfunction visualized in the open field and Y-maze test and modulating the neurochemical parameters such as brain amino acid levels (glutamate, aspartate, serine, and histidine), oxidative stress markers (GSH, MDA, and 8-hydroxy-2'-deoxyguanosine), and purinergic cell energy (adenosine triphosphate (ATP) and adenosine monophosphate (AMP)). In conclusion, the isolated compounds (kaempferol-3-O-β-glucoside and quercetin-3-O-β-glucoside) from the ET-L fraction could serve as potent anticancer agents due to their strong antioxidant, in vitro cytotoxicity, and in vivo neuroprotective activity.

Protocol for the Exercise, Cancer and Cognition - The ECCO-Study: A Randomized Controlled Trial of Simultaneous Exercise During Neo-/Adjuvant Chemotherapy in Breast Cancer Patients and Its Effects on Neurocognition

Introduction

Epidemiological studies show that increased physical activity is linked to a lower risk of breast cancer and mortality. As a result, physical activity can significantly improve patients' quality of life (QOL) both during and after therapy.Many breast cancer patients demonstrate a decrease in cognitive capacity, referred to as the symptom-complex cancer related cognitive impairment (CRCI). Most frequently reported impairments are mild to moderate deficits in processing speed, attention, memory, and executive functions. Cognitive symptoms persist for months or even years, following medical treatment in roughly 35% of afflicted people, impairing everyday functioning, limiting the ability to return to work, and lowering the overall QOL. Recent studies point toward a key role of inflammatory pathways in the CRCI genesis. Attention to physical activity as a potential supportive care option is therefore increasing. However, evidence for the positive effects of exercise on preventing CRCI is still lacking.

Patients and Methods

Against this background, the prospective, two-arm, 1:1 randomized, controlled trial investigates the influence of first line chemotherapy accompanied by exercise training on preventing CRCI in 126 patients with breast cancer at the local University Hospital. The study will evaluate biomarkers and secondary assessments suspected to be involved in the pathogenesis of CRCI in addition to objective (primary outcome) and subjective cognitive function. CRCI is believed to be connected to either functional and/or morphological hippocampal damage due to chemotherapy. Thus, cerebral magnetic resonance imaging (MRI) and hippocampal volume measurements are performed. Furthermore, a specific neuropsychological test battery for breast cancer patients has been developed to detect early signs of cognitive impairments in patients and to be integrated into practice.

Discussion

This study will explore how a long-term supervised exercise intervention program might prevent CRCI, enables optimization of supportive care and objectifies limits of psychological and physical resilience in breast cancer patients during and after chemotherapy treatment.

Trial Registration

ClinicalTrials.gov: Identifier: NCT04789187. Registered on 09 March 2021.

Prevalence of cognitive impairment following chemotherapy treatment for breast cancer: a systematic review and meta-analysis

Breast cancer survival rates have markedly improved. Consequently, survivorship issues have received increased attention. One common sequel of treatment is chemotherapy-induced cognitive impairment (CICI). CICI causes a range of impairments that can have a significant negative impact on quality of life. Knowledge of the prevalence of this condition is required to inform survivorship plans, and ensure adequate resource allocation and support is available for sufferers, hence a systematic review of prevalence data was performed. Medline, Scopus, CINAHL and PSYCHInfo were searched for eligible studies which included prevalence data on CICI, as ascertained though the use of self-report, or neuropsychological tests. Methodological quality of included studies was assessed. Findings were synthesised narratively, with meta-analyses being used to calculate pooled prevalence when impairment was assessed by neuropsychological tests. The review included 52 studies. Time-points considered ranged from the chemotherapy treatment period to greater than 10 years after treatment cessation. Summary prevalence figures (across time-points) using self-report, short cognitive screening tools and neuropsychological test batteries were 44%, 16% and 21–34% respectively (very low GRADE evidence). Synthesised findings demonstrate that 1 in 3 breast cancer survivors may have clinically significant cognitive impairment. Prevalence is higher when self-report based on patient experience is considered. This review highlights a number of study design issues that may have contributed to the low certainty rating of the evidence. Future studies should take a more consistent approach to the criteria used to assess impairment. Larger studies are urgently needed.

Targeting the A3 adenosine receptor to prevent and reverse chemotherapy-induced neurotoxicities in mice

Cisplatin is used to combat solid tumors. However, patients treated with cisplatin often develop cognitive impairments, sensorimotor deficits, and peripheral neuropathy. There is no FDA-approved treatment for these neurotoxicities. We investigated the capacity of a highly selective A₃ adenosine receptor (AR) subtype (A₃AR) agonist, MRS5980, to prevent and reverse cisplatin-induced neurotoxicities. MRS5980 prevented cisplatin-induced cognitive impairment (decreased executive function and impaired spatial and working memory), sensorimotor deficits, and neuropathic pain (mechanical allodynia and spontaneous pain) in both sexes. At the structural level, MRS5980 prevented the cisplatin-induced reduction in markers of synaptic integrity. In-situ hybridization detected Adora3 mRNA in neurons, microglia, astrocytes and oligodendrocytes. RNAseq analysis identified 164 genes, including genes related to mitochondrial function, of which expression was changed by cisplatin and normalized by MRS5980. Consistently, MRS5980 prevented cisplatin-induced mitochondrial dysfunction and decreased signs of oxidative stress. Transcriptomic analysis showed that the A₃AR agonist upregulates genes related to repair pathways including NOTCH1 signaling and chromatin modification in the cortex of cisplatin-treated mice. Importantly, A₃AR agonist administration after completion of cisplatin treatment resolved cognitive impairment, neuropathy and sensorimotor deficits. Our results highlight the efficacy of a selective A₃AR agonist to prevent and reverse cisplatin-induced neurotoxicities via preventing brain mitochondrial damage and activating repair pathways. An A₃AR agonist is already in cancer, clinical trials and our results demonstrate management of neurotoxic side effects of chemotherapy as an additional therapeutic benefit.

Long-Term Cognitive Dysfunction in Cancer Survivors

Cancer-related cognitive impairment (CRCI) is a frequent side effect experienced by an increasing number of cancer survivors with a significant impact on their quality of life. Different definitions and means of evaluation have been used in available literature; hence the exact incidence of CRCI remains unknown. CRCI can be described as cognitive symptoms reported by cancer patients in self-reported questionnaires or as cognitive changes evaluated by formal neuropsychological tests. Nevertheless, association between cognitive symptoms and objectively assessed cognitive changes is relatively weak or absent. Studies have focused especially on breast cancer patients, but CRCI has been reported in multiple types of cancer, including colorectal, lung, ovarian, prostate, testicular cancer and hematological malignancies. While CRCI has been associated with various treatment modalities, including radiotherapy, chemotherapy, hormone therapy and novel systemic therapies, it has been also detected prior to cancer treatment. Therefore, the effects of cancer itself with or without the psychological distress may be involved in the pathogenesis of CRCI as a result of altered coping mechanisms after cancer diagnosis. The development of CRCI is probably multifactorial and the exact mechanisms are currently not completely understood. Possible risk factors include administered treatment, genetic predisposition, age and psychological factors such as anxiety, depression or fatigue. Multiple mechanisms are suggested to be responsible for CRCI, including direct neurotoxic injury of systemic treatment and radiation while other indirect contributing mechanisms are hypothesized. Chronic neuroinflammation mediated by active innate immune system, DNA-damage or endothelial dysfunction is hypothesized to be a central mechanism of CRCI pathogenesis. There is increasing evidence of potential plasma (e.g., damage associated molecular patterns, inflammatory components, circulating microRNAs, exosomes, short-chain fatty acids, and others), cerebrospinal fluid and radiological biomarkers of cognitive dysfunction in cancer patients. Discovery of biomarkers of cognitive impairment is crucial for early identification of cancer patients at increased risk for the development of CRCI or development of treatment strategies to lower the burden of CRCI on long-term quality of life. This review summarizes current literature on CRCI with a focus on long-term effects of different cancer treatments, possible risk factors, mechanisms and promising biomarkers.

Antioxidant and Anti-inflammatory Properties Mediate the Neuroprotective Effects of Hydro-ethanolic Extract of Tiliacora triandra Against Cisplatin-induced Neurotoxicity

Background

Cisplatin (CDDP) is an efficacious anticancer agent used widely in chemotherapy despite its severe side effect related to neurotoxicity. Redox imbalance and inflammatory mechanism have been implicated in the pathophysiology of CDDP-induced neurotoxicity. Herein, we investigated whether Tiliacora triandra (TT) extract could inhibit  CDDP-induced redox-mediated neurotoxicity and behavioural deficit in rats.

Materials and Methods

CDDP-induced redox-mediated neurotoxicity and behavioral deficit in rats. Rats were administered TT for five consecutive weeks (250 and 500 mg/kg bw), while weekly i.p. injection of CDDP commenced on the second week (2.5 mg/kg bw) of the TT administration.

Results

CCDDP caused significant body weight reduction and cognitive diminution as revealed by Morris water maze and Y maze tests. In the CDDP-induced cognitive impairment (CICI) rats, there were remarkable increases in the brain levels of TNF-α, IL-6 and IL-1β and malondialdehyde (MDA), whereas catalase (CAT), glutathione (GSH), glutathione peroxidase (GPx) and superoxide dismutase (SOD) activities considerably decreased compared to normal control. The brain acetylcholinesterase (AChE) activity in CDDP control rats was significantly increased compared to the normal control. The expression of caspase-3 and p53 proteins was upregulated by CDDP injection, whereas Bcl2 was downregulated coupled with histopathological alterations in the rat brain. Interestingly, treatment with TT significantly abated neurobehavioral deficits, MDA and cytokine levels and restored CAT, GPx, GSH, SOD, and AChE activities compared to the CDDP control rats. Caspase-3 level as well as Bcl2 and p53 expressions were modulated with alleviated changes in histopathology.

Conclusion

The findings highlight neuroprotective and cognitive function improvement efficacy of TT against CICI via redox-inflammatory balance and antiapoptotic mechanism in rats.

RETRACTED: Melatonin rescues the mice brain against cisplatin-induced neurodegeneration, an insight into antioxidant and anti-inflammatory effects

This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). This article has been retracted at the request of the Editors-in-Chief. Figure 1C appears similar to Figure 5h of the article published by Oxidative Medicine and Cellular Longevity 2021 (2021) Article ID 6635552 https://doi.org/10.1155/2021/6635552, Figure 5a of the article published by Cells 10 (2021) 2719 https://doi.org/10.3390/cells10102719 and Figure 8a of the article published by Molecular Neurobiology 56 (2019) 6293–6309 https://doi.org/10.1007/s12035-019-1512-7. Although this article was published earlier than the Cells article, the Editors decided to retract this article given concerns about the reliability of the data. Also, sections of panels within Figures 1H and 2G appear similar to each other. The journal records indicated that the names of the authors Reem Alshaman and Muhammad Imran Khan were added to the revised version of the article without exceptional approval by the handling Editor, which is contrary to the journal policy on changes to authorship.

Four decades of chemotherapy-induced cognitive dysfunction: comprehensive review of clinical, animal and in vitro studies, and insights of key initiating events

Cognitive dysfunction has been one of the most reported and studied adverse effects of cancer treatment, but, for many years, it was overlooked by the medical community. Nevertheless, the medical and scientific communities have now recognized that the cognitive deficits caused by chemotherapy have a strong impact on the morbidity of cancer treated patients. In fact, chemotherapy-induced cognitive dysfunction or 'chemobrain'  (also named also chemofog) is at present a well-recognized effect of chemotherapy that could affect up to 78% of treated patients. Nonetheless, its underlying neurotoxic mechanism is still not fully elucidated. Therefore, this work aimed to provide a comprehensive review using PubMed as a database to assess the studies published on the field and, therefore, highlight the clinical manifestations of chemobrain and the putative neurotoxicity mechanisms.In the last two decades, a great number of papers was published on the topic, mainly with clinical observations. Chemotherapy-treated patients showed that the cognitive domains most often impaired were verbal memory, psychomotor function, visual memory, visuospatial and verbal learning, memory function and attention. Chemotherapy alters the brain's metabolism, white and grey matter and functional connectivity of brain areas. Several mechanisms have been proposed to cause chemobrain but increase of proinflammatory cytokines with oxidative stress seem more relevant, not excluding the action on neurotransmission and cellular death or impaired hippocampal neurogenesis. The interplay between these mechanisms and susceptible factors makes the clinical management of chemobrain even more difficult. New studies, mainly referring to the underlying mechanisms of chemobrain and protective measures, are important in the future, as it is expected that chemobrain will have more clinical impact in the coming years, since the number of cancer survivors is steadily increasing.

Cisplatin Mouse Models: Treatment, Toxicity and Translatability

Cisplatin is one of the most widely used chemotherapeutic drugs in the treatment of a wide range of pediatric and adult malignances. However, it has various side effects which limit its use. Cisplatin mouse models are widely used in studies investigating cisplatin therapeutic and toxic effects. However, despite numerous promising results, no significant improvement in treatment outcome has been achieved in humans. There are many drawbacks in the currently used cisplatin protocols in mice. In the paper, the most characterized cisplatin protocols are summarized together with weaknesses that need to be improved in future studies, including hydration and supportive care. As demonstrated, mice respond to cisplatin treatment in similar ways to humans. The paper thus aims to illustrate the complexity of cisplatin side effects (nephrotoxicity, gastrointestinal toxicity, neurotoxicity, ototoxicity and myelotoxicity) and the interconnectedness and interdependence of pathomechanisms among tissues and organs in a dose- and time-dependent manner. The paper offers knowledge that can help design future studies more efficiently and interpret study outcomes more critically. If we want to understand molecular mechanisms and find therapeutic agents that would have a potential benefit in clinics, we need to change our approach and start to treat animals as patients and not as tools.

The Antagonism of the Prokineticin System Counteracts Bortezomib Induced Side Effects: Focus on Mood Alterations

The development of neuropathy and of mood alterations is frequent after chemotherapy. These complications, independent from the antitumoral mechanism, are interconnected due to an overlapping in their processing pathways and a common neuroinflammatory condition. This study aims to verify whether in mice the treatment with the proteasome inhibitor bortezomib (BTZ), at a protocol capable of inducing painful neuropathy, is associated with anxiety, depression and supraspinal neuroinflammation. We also verify if the therapeutic treatment with the antagonist of the prokineticin (PK) system PC1, which is known to contrast pain and neuroinflammation, can prevent mood alterations. Mice were treated with BTZ (0.4 mg/kg three times/week for 4 weeks); mechanical allodynia and locomotor activity were evaluated over time while anxiety (dark light and marble burying test), depression (sucrose preference and swimming test) and supraspinal neuroinflammation were checked at the end of the protocol. BTZ treated neuropathic mice develop anxiety and depression. The presence of mood alterations is related to the presence of neuroinflammation and PK system activation in prefrontal cortex, hippocampus and hypothalamus with high levels of PK2 and PKR2 receptor, IL-6 and TNF-α, TLR4 and an upregulation of glial markers. PC1 treatment, counteracting pain, prevented the development of supraspinal inflammation and depression-like behavior in BTZ mice.

Neuroinflammation and Its Association with Cognition, Neuronal Markers and Peripheral Inflammation after Chemotherapy for Breast Cancer

Simple Summary

Up to 70% of chemotherapy-treated patients experience problems with memory and concentration, potentially caused by direct and indirect neurotoxicity, such as (neuro-)inflammatory processes. Can neuroinflammation changes be detected in chemotherapy-treated patients with breast cancer using translocator protein [¹⁸F]DPA714 simultaneous positron emission tomographic- and magnetic resonance imaging? Moreover, what is the association with clinical biomarkers? In a study including 19 chemotherapy-treated breast cancer patients, 18 chemotherapy-naïve and 37 healthy controls, we found significant relative glial overexpression in parietal and occipital brain regions in chemotherapy-treated patients compared to controls, which were associated with cognitive abnormalities and markers of neuronal survival. Shortly after ending chemotherapy, changes in brain neuroinflammation seem to occur, possibly contributing to the cognitive decline seen in breast cancer patients. Additionally, blood levels of an axonal damage marker were 20-fold higher in chemotherapy-treated patients, providing evidence for its use as a biomarker to assess neurotoxic effects of anticancer chemotherapies.

Abstract

To uncover mechanisms underlying chemotherapy-induced cognitive impairment in breast cancer, we studied new biomarkers of neuroinflammation and neuronal survival. This cohort study included 74 women (47 ± 10 years) from 22 October 2017 until 20 August 2020. Nineteen chemotherapy-treated and 18 chemotherapy-naïve patients with breast cancer were assessed one month after the completion of surgery and/or chemotherapy, and 37 healthy controls were included. Assessments included neuropsychological testing, questionnaires, blood sampling for 17 inflammatory and two neuronal survival markers (neurofilament light-chain (NfL), and brain-derived neurotrophic factor (BDNF) and PET-MR neuroimaging. To investigate neuroinflammation, translocator protein (TSPO) [¹⁸F]DPA714-PET-MR was acquired for 15 participants per group, and evaluated by volume of distribution normalized to the cerebellum. Chemotherapy-treated patients showed higher TSPO expression, indicative for neuroinflammation, in the occipital and parietal lobe when compared to healthy controls or chemotherapy-naïve patients. After partial-volume correction, differences with healthy controls persisted (p_FWE < 0.05). Additionally, compared to healthy- or chemotherapy-naïve controls, cognitive impairment (17–22%) and altered levels in blood markers (F ≥ 3.7, p ≤ 0.031) were found in chemotherapy-treated patients. NfL, an axonal damage marker, was particularly sensitive in differentiating groups (F = 105, p = 4.2 × 10 ⁻²¹), with levels 20-fold higher in chemotherapy-treated patients. Lastly, in chemotherapy-treated patients alone, higher local TSPO expression was associated with worse cognitive performance, higher blood levels of BDNF/NfL, and decreased fiber cross-section in the corpus callosum (p_FWE < 0.05). These findings suggest that increased neuroinflammation is associated with chemotherapy-related cognitive impairment in breast cancer. Additionally, NfL could be a useful biomarker to assess neurotoxic effects of anticancer chemotherapies.

Change in cognition before and after non-central nervous system cancer diagnosis: A population-based cohort study

OBJECTIVE

Clinical studies showing that non-central nervous system cancer patients can develop cognitive impairment have primarily focused on patients with specific cancer types and intensive treatments. To better understand the course of cognitive function in the general population of cancer patients, we assessed cognitive trajectories of patients before and after cancer diagnosis in a population-based setting.

METHODS

Between 1989 and 2014, 2211 participants from the population-based Rotterdam study had been diagnosed with cancer of whom 718 (32.5%) had undergone ≥1 cognitive assessment before and after diagnosis. Cognition was measured every 3 to 6 years using a neuropsychological battery. Linear mixed models were used to compare cognitive trajectories of patients before and after diagnosis with those of age-matched cancer-free controls (1:3).

RESULTS

Median age at cancer diagnosis was 70.3 years and 47.1% were women. Most patients (68.1%) had received local treatment only. Cognitive trajectories of patients before and after cancer diagnosis were largely similar to those of controls. After diagnosis, the largest difference was found on a memory test (patients declined with 0.14 units per year on the Word Learning Test: delayed recall [95% CI = -0.35; 0.07] and controls with 0.09 units [95% CI = -0.18;-0.00], p for difference = .59).

CONCLUSIONS

In this longitudinal cohort, cancer did not appear to alter the trajectory of change in cognitive test results over time from that seen in similar individuals without cancer, although most cancer patients did not receive systemic therapies. Future studies should focus on identifying subgroups of patients who are at high risk for developing cognitive impairment.

Apelin-13 activates the hippocampal BDNF/TrkB signaling pathway and suppresses neuroinflammation in male rats with cisplatin-induced cognitive dysfunction

It has been established that cisplatin causes neuronal damage and cognitive impairment. However, the mechanism is not sufficiently clear. Apelin-13 is an endogenous peptide with strong neuroprotective effects through the synthesis of neurotrophic factors and suppression of inflammation. The aim of this study was to investigate the role of brain-derived neurotrophic factor/tropomyosin receptor kinase B (BDNF/TrkB) signaling pathway and the potential inhibitory effects of apelin-13 in the mechanism of cisplatin-induced hippocampal damage and cognitive impairment. Apelin-13 was administered to adult sprague dawley male rats at a dose of 20 nmol/kg every day for 4 weeks, cisplatin was administered at a dose of 5 mg/kg once a week for 4 weeks. The spatial and recognition memory tests of the rats were performed on the 5th week. BDNF and the inflammatory cytokines tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) levels were measured by ELISA in hippocampal homogenates. Pyramidal neuron and glial cell damage in the hippocampal CA1, CA3 and dentate gyrus (DG) were analyzed histologically. TrkB activity in the hippocampus was determined by immunohistochemical methods. Cisplatin impaired spatial and recognition memory in rats, while apelin-13 improved spatial memory but did not affect recognition memory. Cisplatin suppressed BDNF in the hippocampus while increased IL-1β and TNF-α. In contrast, apelin-13 administration increased BDNF but significantly suppressed TNF-α and IL-1B. Cisplatin caused pyramidal neuron and glial cell damage in CA1, CA3 and DG. In the cisplatin + apelin-13 group, however, pyramidal neuron and glial cell damage was less than those without apelin-13. Cisplatin increased TrkB activity in the hippocampus, which was counteracted by apelin-13. In conclusion, apelin-13 reduced the cisplatin-induced cognitive deficiency, by suppressing inflammation and stimulating the synthesis and activation of neurotrophic factors in hippocampal tissue.

Long-term clinically relevant rodent model of methotrexate-induced cognitive impairment

BACKGROUND

With the enhanced use of chemotherapy and the advent of increased patient survival rates, there are an increasing number of cancer survivors living with chemotherapy-induced cognitive impairment. A growing number of clinical studies have brought to light the association of agents like methotrexate in generating these neurological sequelae, although mechanisms remain unclear.

METHODS

Here, we use a clinically relevant regimen of several cycles of methotrexate and leucovorin rescue to develop a model of chemotherapy-induced cognitive impairment, and investigate the in vivo long-term (16 mo) impact of high-dose systemic methotrexate on white matter cellular dynamics as assessed by stereology, animal behavior, and diffusion tensor imaging.

RESULTS

Our results indicate that at 6 and 16 months post-chemotherapy, methotrexate-treated rats exhibit a significant and permanent decrease in the number of oligodendrocytes and their progenitors in the white matter, in corpus callosum volumes, and myelin basic protein. These findings are associated with mostly delayed deficits in performance on Morris Water Maze and Novel Object Recognition tasks. Diffusion tensor imaging demonstrates significantly decreased fractional anisotropy values in the callosum genu, body, and splenium, as well as previously unassessed areas like the fimbria. Interestingly, these white matter changes are preceded by an earlier, transient decrement in white matter microglia at 3 months, and hippocampal neural progenitors at 3 and 6 months.

CONCLUSION

These results demonstrate a significant negative impact of methotrexate on the oligodendrocyte compartment and white matter, associated with cognitive impairment. The data also support the use of diffusion tensor imaging in monitoring white matter integrity in this context.

Animal models of chemotherapy-induced cognitive decline in preclinical drug development

RATIONALE

Chemotherapy-induced cognitive impairment (CICI), chemobrain, and chemofog are the common terms for mental dysfunction in a cancer patient/survivor under the influence of chemotherapeutics. CICI is manifested as short/long term memory problems and delayed mental processing, which interferes with a person's day-to-day activities. Understanding CICI mechanisms help in developing therapeutic interventions that may alleviate the disease condition. Animal models facilitate critical evaluation to elucidate the underlying mechanisms and form an integral part of verifying different treatment hypotheses and strategies.

OBJECTIVES

A methodical evaluation of scientific literature is required to understand cognitive changes associated with the use of chemotherapeutic agents in different preclinical studies. This review mainly emphasizes animal models developed with various chemotherapeutic agents individually and in combination, with their proposed mechanisms contributing to the cognitive dysfunction. This review also points toward the analysis of chemobrain in healthy animals to understand the mechanism of interventions in absence of tumor and in tumor-bearing animals to mimic human cancer conditions to screen potential drug candidates against chemobrain.

RESULTS

Substantial memory deficit as a result of commonly used chemotherapeutic agents was evidenced in healthy and tumor-bearing animals. Spatial and episodic cognitive impairments, alterations in neurotrophins, oxidative and inflammatory markers, and changes in long-term potentiation were commonly observed changes in different animal models irrespective of the chemotherapeutic agent.

CONCLUSION

Dyscognition exists as one of the serious side effects of cancer chemotherapy. Due to differing mechanisms of chemotherapeutic agents with differing tendencies to alter behavioral and biochemical parameters, chemotherapy may present a significant risk in resulting memory impairments in healthy as well as tumor-bearing animals.

Heterogeneous Response of Chemotherapy-Related Cognitive Decline in Patients with Breast Cancer: A Prospective Study

OBJECTIVE

A significant proportion of adjuvant-treated breast cancer patients experience cognitive decline, challenging the person's ability to return to normal activities after treatment. However, not every patient experiences cognitive problems, and even in patients with impairments, determining clinically important cognitive decline remains challenging. Our objective was to explore differences in neuropsychological performance following adjuvant chemotherapy (CT) in patients with breast cancer.

METHOD

We conducted a prospective observational study in an Oncology Breast Clinic and assessed neuropsychological performance before and after adjuvant CT and in non-CT-treated women with breast cancer and healthy controls (HCs). Standardised between-group differences and regression-based change scores were calculated.

RESULTS

CT-treated patients (n = 66) performed significantly different from non-CT-treated patients (n = 39) and HCs (n = 56). There was a significant effect on verbal fluency (p = .0013). CT performed significantly worse than non-CT and HC [effect size (ES) = .89, p < .001 and ES = .61, p ≤ .001, respectively] and from HCs with regard to proactive interference (ES = .62, p ≤ .001). Regression-based scores revealed more severe cognitive decline in the CT-treated group [24.24% (16/66)] than in the non-CT-treated group [15.20% (6/39)] and HC group [7.14% (4/56)]. Patients who underwent CT and showed cognitive decline were less educated and older, with significantly lower baseline scores.

CONCLUSIONS

CT-treated patients showed more vulnerability on cognitive control and monitoring than non-CT-treated breast cancer patients and HCs. Older patients with less education and lower baseline cognitive performance represent a group at risk for cognitive decline following CT. Identification of patients at risk for decline could improve targeted support and rehabilitation.

Chemotherapy-induced cognitive impairment (CICI): An overview of etiology and pathogenesis

Many cancer patients treated with chemotherapy develop chemotherapy-induced cognitive impairment (CICI), often referred to as chemo-brain, which manifest during or post-treatment with variable degrees, onset and duration thereby affecting the patients' quality of life. Several chemotherapeutic agents have been studied to determine its possible association with cognitive impairment and to fully comprehend their contribution to CICI. A vast number of studies have emerged proposing several candidate underlying mechanisms and etiologies contributing to CICI such as direct neurotoxicity, BBB disruption, decreased hippocampal neurogenesis, white matter abnormalities, secondary neuro-inflammatory response and increased oxidative stress; however, the exact underlying mechanisms are still not well defined. This review summarizes CICI associated with most commonly used chemotherapeutic agents with emphasizes the possible underlying pathogenesis in both animal and clinical studies.

Ginkgo biloba Alleviates Cisplatin-Mediated Neurotoxicity in Rats via Modulating APP/Aβ/P2X7R/P2Y12R and XIAP/BDNF-Dependent Caspase-3 Apoptotic Pathway

Neurotoxicity is an obvious adverse effect in Patients encountering a complete course of chemotherapy. The present work is conducted to evaluate the neuroprotective effect of Ginkgo biloba (Ginkgo) against the neurotoxicity induced by Cisplatin (Cis) in rats. Forty male Wistar albino rats were arranged into four groups: (1) Control group, rats were given saline; (2) Cis group, rats were injected by Cis 2 mg/kg body weight i.p., twice a week starting on the fifth day for thirty days; (3) Ginkgo group, rats were administered Ginkgo (50 mg/kg orally) daily for thirty days; and (4) Ginkgo+Cis group, rats received Ginkgo (50 mg/kg orally) daily and on the fifth day, rats were injected with Cis (2 mg/Kg body weight i.p.) twice a week for thirty days. Cis significantly increased Gamma glutamyltransferase (GGT) and Acetyl Cholinesterase (CHE) as compared to the control group and also disturbed cerebral oxidative/antioxidant redox. Co-administration of Ginkgo and Cis reversed the adverse effect of Cis on the brain tissue. Moreover, co-administration of Ginkgo and Cis ameliorated Cis induced brain damage by reducing Amyloid precursor protein (APP), amyloid β (Aβ), P2Y12R and P2X7R mRNA expressions and proteins. Furthermore, Ginkgo regulated XIAP/BDNF expressions with a consequent decrease of caspase-3 and DNA fragmentation%. The current results concluded that concurrent treatment with Ginkgo can mitigate neurotoxicity mediated by Cis in experimental animals through exhibiting antioxidant effect by restoring cerebral oxidative/antioxidant redox and anti-apoptotic effect via regulating cerebral APP/Aβ/P2Y12R/P2X7R and XIAP/BDNF signaling pathways.

Chemotherapy-induced brain changes in breast cancer survivors: evaluation with multimodality magnetic resonance imaging

Chemotherapy related cognitive impairments are common in breast cancer patients undergoing chemotherapy. These cognitive dysfunctions are mainly attributable to chemotherapy related brain structural and functional alterations. Multimodality magnetic resonance imaging (MRI) can reveal brain gray matter volume loss, white matter microstructural disruption, reduced gray matter density, impaired cerebral blood flow and brain structural and functional connection networks at both local and global levels. This review outlines the potential applications of multimodality MR imaging techniques in chemotherapy induced cognitive deficit in breast cancer survivors and provides future research perspective in this field.

A mouse model of chemotherapy-related cognitive impairments integrating the risk factors of aging and APOE4 genotype

Some cancer survivors experience marked cognitive impairment, referred to as cancer-related cognitive impairment (CRCI). CRCI has been linked to the genetic factor APOE4, the strongest genetic risk factor for Alzheimer's disease (AD). We used APOE knock-in mice to test whether the relationship between APOE4 and CRCI can be demonstrated in a mouse model, to identify associations of chemotherapy with behavioural and structural correlates of cognition, and to test whether chemotherapy affects markers of AD. Twelve-month old C57BL/6 J female APOE3 (n = 30) and APOE4 (n = 31) knock-in mice were randomized to treatment with either doxorubicin (10 mg/kg) or saline. Behavioural assays at 2-21 weeks-post exposure included open field maze, elevated zero maze, pre-pulse inhibition, Barnes maze, and fear conditioning. Ex-vivo magnetic resonance imaging was used to determine regional volume differences at 31-35 weeks-post exposure, and tissue sections were analyzed for markers of AD pathogenesis. Minimal toxicities were observed in the aged mice after doxorubicin exposure. In the Barnes maze assay, APOE3 mice did not exhibit impairment in spatial learning after doxorubicin treatment, but APOE4 mice demonstrated significant impairments in both the initial identification of the escape hole and the latency to full escape at 6 weeks post-exposure. Both APOE3 and APOE4 mice treated with doxorubicin showed impairment of spatial memory. Grey matter volume in the frontal cortex decreased in APOE4 mice treated with doxorubicin vs. APOE3 mice. This study demonstrates cognitive impairments in aged APOE4 knock-in mice after doxorubicin treatment and establishes this system as a novel and powerful model of CRCI.

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.

Mitochondrial-associated impairments of temozolomide on neural stem/progenitor cells and hippocampal neurons

Primary brain tumor patients often experience neurological, cognitive, and depressive symptoms that profoundly affect quality of life. The DNA alkylating agent, temozolomide (TMZ), along with radiation therapy forms the standard of care for glioblastoma (GBM) - the most common and aggressive of all brain cancers. Numerous studies have reported that TMZ disrupts hippocampal neurogenesis and causes spatial learning deficits in rodents; however, the effect of TMZ on mature hippocampal neurons has not been addressed. In this study, we examined the mitochondrial-mediated mechanisms involving TMZ-induced neural damage in primary rat neural stem/progenitor cells (NSC) and hippocampal neurons. TMZ inhibited mtDNA replication and transcription of mitochondrial genes (ND1 and Cyt b) in NSC by 24 h, whereas the effect of TMZ on neuronal mtDNA transcription was less pronounced. Transmission electron microscopy imaging revealed mitochondrial degradation in TMZ-treated NSC. Acute TMZ exposure (4 h) caused a rapid reduction in dendritic branching and loss of postsynaptic density-95 (PSD95) puncta on dendrites. Longer TMZ exposure impaired mitochondrial respiratory activity, increased oxidative stress, and induced apoptosis in hippocampal neurons. The presented findings suggest that NSC may be more vulnerable to TMZ than hippocampal neurons upon acute exposure; however long-term TMZ exposure results in neuronal mitochondrial respiratory dysfunction and dendritic damage, which may be associated with delayed cognitive impairments.

Overview of cisplatin-induced neurotoxicity and ototoxicity, and the protective agents

Cisplatin has dramatically improved the survival rate of cancer patients, but it has also increased the prevalence of hearing and neurological deficits in this population. Cisplatin induces ototoxicity, peripheral (most prevalent) and central (rare) neurotoxicity. This review addresses the ototoxicity and the neurotoxicity associated with cisplatin-based chemotherapy, providing an integrated view of the potential protective agents that have been evaluated in vitro, in vivo and in clinical trials, their targets and mechanisms of protection and their effects on the antitumor activity of cisplatin. So far, the findings are insufficient to support the use of any oto- or neuroprotective agent before, during or after cisplatin chemotherapy. Despite their promising effects in vitro and in animal studies, many agents have not been evaluated in clinical trials. Additionally, the clinical trials have limitations concerning the sample size, controls, measurement, heterogeneous groups, several arms of treatment, short follow-up or no blinding. Besides that, for most agents, the effects on the antitumor activity of cisplatin have not been evaluated in tumor-bearing animals, which discourages clinical trials. Further well-designed randomized controlled clinical trials are necessary to definitely demonstrate the effectiveness of the oto- or neuroprotective agents proposed by animal and in vitro studies.

Cognitive impairments in breast cancer survivors treated with chemotherapy: a study based on event-related potentials

PURPOSE

Chemotherapy-related cognitive impairments in breast cancer patients were usually reported through cognitive questionnaires or scales which may be subjective and insensitive. This study is to assess the effect of chemotherapy on cognitive function in breast cancer patients stratified by age using objective electrophysiological measure, the P300 component of event-related potentials (ERPs) with a large sample size.

METHODS

Totally, 529 primary breast cancer patients, including 178 cases at initial diagnosis stage and before chemotherapy (Group1), 167 cases during chemotherapy (Group2), and 184 cases post chemotherapy and during follow-up period (Group3), were examined with ERPs (P300 component) to assess the effect of chemotherapy on their cognitive function.

RESULTS

There were significant differences of P300 latency in Group2 (364.74 ± 15.73 ms) and Group3 (364.02 ± 17.12 ms, mean follow-up period of 2.42 years) compared with Group1 (355.13 ± 19.47 ms, P < 0.001), respectively. With further age stratification: in patients of < 50 years, P300 latency was significantly prolonged in Group2 and Group3 compared with Group1 (P < 0.001), respectively; in patients of 50-59 years, P300 latency was significantly prolonged in Group2 compared with Group1 (P < 0.05), but without difference in Group1 and Group3 (P>0.05); In patients of ≥ 60 years, there were no differences of P300 latency among three the groups (P>0.05).

CONCLUSIONS

It is first suggested by our objective detection data that the side effect of chemotherapy on cognitive functions in breast cancer patients may decrease with age. Electrophysiological cognitive impairments mainly occur in younger breast cancer patients undergoing chemotherapy and would last for years after chemotherapy, which highlights the importance of early intervention for those patients, especially in younger patients.

Prokineticin 2 promotes and sustains neuroinflammation in vincristine treated mice: Focus on pain and emotional like behavior

Vincristine (VCR) treatment is often associated to painful neuropathy. Its development is independent from antitumoral mechanism and involves neuroinflammation. We investigated the role of the chemokine prokineticin (PK)2 in a mouse model of VCR induced neuropathy using a PK-receptors (PK-R) antagonist to counteract its development. We also evaluated emotional like deficits in VCR mice. VCR (0,1 mg/kg) was i.p. injected in C57BL/6J male mice once a day for 14 consecutive days. Pain, anxiety and depressive like behaviors were assessed in animals. PK2, PK-Rs, cytokines, neuroinflammatory markers (CD68, CD11b, GFAP, TLR4) and ATF3 were evaluated in DRG, spinal cord, prefrontal cortex and hippocampus. The PK-Rs antagonist PC1, was s.c. injected (150 μg/kg) twice a day from day 7 (hypersensitivity state) until day 14. Its effect on pain and neuroinflammation was evaluated. VCR mice developed neuropathic pain but not mood alterations. After 7 days of VCR treatment we observed a neuroinflammatory condition in DRG with high levels of PK-Rs, TLR4, CD68, ATF3 and IL-1β without relevant alterations in spinal cord. At day 14, an upregulation of PK system and a marked neuroinflammation was evident also in spinal cord. Moreover, at the same time, we observed initial alterations in supraspinal brain areas. PC1 treatment significantly counteracted neuropathic pain and blunted neuroinflammation.

Evaluation of the susceptibility of neurons and neural stem/progenitor cells derived from human induced pluripotent stem cells to anticancer drugs

Various chemicals, including pharmaceuticals, can induce acute or delayed neurotoxicity in humans. Because isolation of human primary neurons is extremely difficult, toxicity tests for these agents have been performed using in vivo or in vitro models. Human induced pluripotent stem cells (hiPSCs) can be used to establish hiPSC-derived neural stem/progenitor cells (hiPSC-NSPCs), which can then be used to obtain hiPSC-neurons. In this study, we differentiated hiPSC-NSPCs into neurons and evaluated the susceptibility of hiPSC-neurons and parental hiPSC-NSPCs to anticancer drugs in vitro by ATP assay and immunocytostaining. The hiPSC-neurons were more resistant to anticancer drugs than the parental hiPSC-NSPCs. In the toxicity tests, high-dose cisplatin reduced the levels of ELAVL3/4, a neuronal marker, in the hiPSC-neurons. These results suggest that our methodology is potentially applicable for efficient determination of the toxicity of any drug to hiPSC-neurons.

Protective Role of Epigallocatechin Gallate in a Rat Model of Cisplatin-Induced Cerebral Inflammation and Oxidative Damage: Impact of Modulating NF-κB and Nrf2

Cisplatin is a widely used chemotherapeutic agent in treating various types of cancers. However, it can induce neurotoxicity and nephrotoxicity, limiting its dose and clinical use. Although previous studies indicated the direct link between cisplatin-induced central neurotoxicity and oxidative stress, the exact mechanism is not completely understood. Therefore, herein we investigated the effects of prophylactic and concurrent treatment with (-)-epigallocatechin-3-gallate (EGCG), a natural polyphenolic neuroprotective antioxidant, on cisplatin-induced brain toxicity in rats to delineate its molecular mechanism of action. We found that cisplatin initiated a cascade of genetic, biological, and histopathological changes in the brain cortex, inducing inflammatory cytokines, appearance of scattered inflammatory cells, nitro-oxidative stress, and apoptotic proteins in the cerebral cortex. However, EGCG not only protected against cisplatin-induced inflammatory burden but also ameliorated the induction of nitro-oxidative stress and apoptotic proteins triggered by cisplatin in the cerebral cortex of pre- and co-treated rats with respect to their unprotected counterparts. EGCG anti-inflammatory effect here may be attributed to the downregulation of nuclear factor kappa B (NF-κB). Additionally, this natural polyphenol significantly ameliorated cisplatin-elicited reduction in cerebral cortex brain-derived neurotrophic factor and acetylcholine esterase. Upregulation of nuclear factor erythroid 2-related factor 2 (Nrf2) and its downstream heme oxygenase-1 (HO-1) by EGCG prophylactic and concurrent administration here seems also to play a key role in the protective impact of EGCG against cisplatin toxicity through enhancing total antioxidant capacity. Thus, EGCG can be used as a promising prophylactic adjuvant for preventing the development of brain inflammation and oxidative damage associated with cisplatin chemotherapy.

Effect of physical exercise on cognitive function and brain measures after chemotherapy in patients with breast cancer (PAM study): protocol of a randomised controlled trial

INTRODUCTION

After treatment with chemotherapy, many patients with breast cancer experience cognitive problems. While limited interventions are available to improve cognitive functioning, physical exercise showed positive effects in healthy older adults and people with mild cognitive impairment. The Physical Activity and Memory study aims to investigate the effect of physical exercise on cognitive functioning and brain measures in chemotherapy-exposed patients with breast cancer with cognitive problems.

METHODS AND ANALYTICS

One hundred and eighty patients with breast cancer with cognitive problems 2-4 years after diagnosis are randomised (1:1) into an exercise intervention or a control group. The 6-month exercise intervention consists of twice a week 1-hour aerobic and strength exercises supervised by a physiotherapist and twice a week 1-hour Nordic or power walking. The control group is asked to maintain their habitual activity pattern during 6 months. The primary outcome (verbal learning) is measured at baseline and 6 months. Further measurements include online neuropsychological tests, self-reported cognitive complaints, a 3-tesla brain MRI, patient-reported outcomes (quality of life, fatigue, depression, anxiety, work performance), blood sampling and physical fitness. The MRI scans and blood sampling will be used to gain insight into underlying mechanisms. At 18 months online neuropsychological tests, self-reported cognitive complaints and patient-reported outcomes will be repeated.

ETHICS AND DISSEMINATION

Study results may impact usual care if physical exercise improves cognitive functioning for breast cancer survivors.

TRIAL REGISTRATION NUMBER

NTR6104.

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.

Assessment of neurocognitive decline in cancer patients, except brain cancer, under long-term treatment with bevacizumab

PURPOSE

We performed a cross-sectional study of neurocognitive function in non-brain cancer patients treated with long-term bevacizumab.

METHODS/PATIENTS

From 2015 to 2017, we included patients with different types of cancer treated with bevacizumab with or without chemotherapy (BEV; N = 20) or only chemotherapy (ChT; N = 19) for at least 34 weeks, patients who received non-brain radiotherapy (RxT; N = 19), and healthy controls (HC; N = 19) were assessed once at week 34 of treatment (BEV and ChT) or at completion of radiotherapy. Neurocognition was evaluated with the Hopkins Verbal Learning Test-Revised (HVLT-R) total and delayed recall, the Trail Making Test A and B, and the Controlled Oral Word Association Test in the four groups. Non-parametric tests were used to assess differences between groups.

RESULTS

The BEV, ChT, and RxT groups scored significantly lower than the HC group on all tests and especially on the HVLT-R total recall. In no case were the mean scores of the BEV group significantly lower than those of the ChT or RxT groups.

CONCLUSIONS

Neurocognitive impairment was seen even in patients treated with local non-brain radiotherapy. Treatment with bevacizumab for a long period of time does not seem to worsen neurocognitive function to a greater extent than chemotherapy.

Management for Different Glioma Subtypes: Are All Low-Grade Gliomas Created Equal?

Following the identification of key molecular alterations that provided superior prognostication and led to the updated 2016 World Health Organization (WHO) Central Nervous System (CNS) Tumor Classification, the understanding of glioma behavior has rapidly evolved. Mutations in isocitrate dehydrogenase (IDH) 1 and 2 are present in the majority of adult grade 2 and 3 gliomas, and when used in conjunction with 1p/19q codeletion for classification, the prognostic distinction between grade 2 versus grade 3 is diminished. As such, the previously often used term of "low-grade glioma," which referred to grade 2 gliomas, has now been replaced by the phrase "lower-grade glioma" to encompass both grade 2 and 3 tumors. Additional molecular characterization is ongoing to even further classify this heterogeneous group of tumors. With such a colossal shift in the understanding of lower-grade gliomas, management of disease is being redefined in the setting of emerging molecular-genetic biomarkers. In this article, we review recent progress and future directions regarding the surgical, radiotherapeutic, chemotherapeutic, and long-term management of adult lower-grade gliomas.

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.

International Cognition and Cancer Task Force Recommendations for Neuroimaging Methods in the Study of Cognitive Impairment in Non-CNS Cancer Patients

Cancer- and treatment-related cognitive changes have been a focus of increasing research since the early 1980s, with meta-analyses demonstrating poorer performance in cancer patients in cognitive domains including executive functions, processing speed, and memory. To facilitate collaborative efforts, in 2011 the International Cognition and Cancer Task Force (ICCTF) published consensus recommendations for core neuropsychological tests for studies of cancer populations. Over the past decade, studies have used neuroimaging techniques, including structural and functional magnetic resonance imaging (fMRI) and positron emission tomography, to examine the underlying brain basis for cancer- and treatment-related cognitive declines. As yet, however, there have been no consensus recommendations to guide researchers new to this field or to promote the ability to combine data sets. We first discuss important methodological issues with regard to neuroimaging study design, scanner considerations, and sequence selection, focusing on concerns relevant to cancer populations. We propose a minimum recommended set of sequences, including a high-resolution T1-weighted volume and a resting state fMRI scan. Additional advanced imaging sequences are discussed for consideration when feasible, including task-based fMRI and diffusion tensor imaging. Important image data processing and analytic considerations are also reviewed. These recommendations are offered to facilitate increased use of neuroimaging in studies of cancer- and treatment-related cognitive dysfunction. They are not intended to discourage investigator-initiated efforts to develop cutting-edge techniques, which will be helpful in advancing the state of the knowledge. Use of common imaging protocols will facilitate multicenter and data-pooling initiatives, which are needed to address critical mechanistic research questions.

Brain Development and Heart Function after Systemic Single-Agent Chemotherapy in a Mouse Model of Childhood Leukemia Treatment

PURPOSE

Chemotherapy for childhood acute lymphoblastic leukemia (ALL) can cause late-appearing side effects in survivors that affect multiple organs, including the heart and brain. However, the complex ALL treatment regimen makes it difficult to isolate the causes of these side effects and impossible to separate the contributions of individual chemotherapy agents by clinical observation. Using a mouse model, we therefore assessed each of eight representative, systemically-administered ALL chemotherapy agents for their impact on postnatal brain development and heart function.

EXPERIMENTAL DESIGN

Mice were treated systemically with a single chemotherapy agent at an infant equivalent age, then allowed to age to early adulthood (9 weeks). Cardiac structure and function were assessed using in vivo high-frequency ultrasound, and brain anatomy was assessed using high-resolution volumetric ex vivo MRI. In addition, longitudinal in vivo MRI was used to determine the time course of developmental change after vincristine treatment.

RESULTS

Vincristine, doxorubicin, and methotrexate were observed to produce the greatest deficiencies in brain development as determined by volumes measured on MRI, whereas doxorubicin, methotrexate, and l-asparaginase altered heart structure or function. Longitudinal studies of vincristine revealed widespread volume loss immediately following treatment and impaired growth over time in several brain regions.

CONCLUSIONS

Multiple ALL chemotherapy agents can affect postnatal brain development or heart function. This study provides a ranking of agents based on potential toxicity, and thus highlights a subset likely to cause side effects in early adulthood for further study.

Impact of Cognitive Impairment in Patients with Gliomas

OBJECTIVES

To address the estimated rates of incidence, potential underlying etiologies, and cognitive domains affected from diagnosis and treatment. To describe potential cognitive function interventions.

DATA SOURCES

PubMed.

CONCLUSION

Adults with gliomas report that the most distressing, persistent, and greatest negative impact on their lives relates to the cognitive impairment they experience. However, there are several potential interventions that may prevent cognitive decline during treatment or maintain cognitive function long term.

IMPLICATIONS FOR NURSING PRACTICE

Awareness of cognitive sequela that adults with gliomas face can lead to early identification, full neurocognitive profiling, and implementation of evidence-based interventions for those experiencing cognitive impairments following cancer treatment.

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

Chemotherapy-induced cognitive impairment, often referred to as "chemobrain," is a common side effect. In this study, mice received three intraperitoneal injections of a combination of docetaxel, adriamycin, and cyclophosphamide (DAC) at 2-day intervals. A water maze test was used to examine cognitive performance, and manganese-enhanced magnetic resonance imaging (MEMRI) was used to examine hippocampal neuronal activity. The whole brain, prefrontal cortex, hippocampus, and blood samples were then collected for cytokine measurement. The DAC-treated mice displayed a significantly shorter duration spent in and fewer entries into the target quadrant of the water maze than the control mice and a pronounced decrease in MEMRI signal intensity in the hippocampal subregions. In a separate experiment using in vivo transcranial two-photon imaging, DAC markedly eliminated dendritic spines without changing the rate of spine formation, leading to a striking loss of spines in the medial prefrontal cortex. DAC treatment resulted in significant elevations in the levels of the proinflammatory cytokines interleukin 6 (IL-6) and tumor necrosis factor-α (TNF-α) and in significant decreases in the levels of the anti-inflammatory cytokines IL-4 and IL-10 in most of the sera and brain tissues examined. The IL-6 and TNF-α levels of several sera and brain tissues showed strong inverse correlations with the duration and number of entries in the target quadrant of the water maze and with the hippocampal MEMRI signal intensity, but also showed striking positive correlations with spine elimination and loss. These results indicate that chemobrain is associated with cytokine dysregulation and disrupted neuroplasticity of the brain.