Precise timing of audiovisual stimulation conquers chemobrain

In a recent study, Kim et al. utilized gamma entrainment using sensory stimuli (GENUS) to rescue cognitive impairment and glial dysregulation associated with cisplatin and methotrexate chemotherapy, specifically when applied both throughout and after chemotherapy administration. GENUS provides a time-dependent, non-invasive method for treating chemobrain, with broader implications for resolving neurodegenerative neuroinflammation.

Frontal and anterior temporal hypometabolism post chemoradiation in head and neck cancer: A real-world PET study

BACKGROUND AND PURPOSE

Adverse neurological effects after cancer therapy are common, but biomarkers to diagnose, monitor, or risk stratify patients are still not validated or used clinically. An accessible imaging method, such as fluorodeoxyglucose positron emission tomography (FDG PET) of the brain, could meet this gap and serve as a biomarker for functional brain changes. We utilized FDG PET to evaluate which brain regions are most susceptible to altered glucose metabolism after chemoradiation in patients with head and neck cancer (HNCa).

METHODS

Real-world FDG PET images were acquired as standard of care before and after chemoradiation for HNCa in 68 patients. Linear mixed-effects voxelwise models assessed changes after chemoradiation in cerebral glucose metabolism quantified with standardized uptake value ratio (SUVR), covarying for follow-up time and patient demographics.

RESULTS

Voxelwise analysis revealed two large clusters of decreased glucose metabolism in the medial frontal and polar temporal cortices following chemoradiation, with decreases of approximately 5% SUVR after therapy.

CONCLUSIONS

These findings provide evidence that standard chemoradiation for HNCa can lead to decreased neuronal glucose metabolism, contributing to literature emphasizing the vulnerability of the frontal and anterior temporal lobes, especially in HNCa, where these areas may be particularly vulnerable to indirect radiation-induced injury. FDG PET shows promise as a sensitive biomarker for assessing these changes.

Role of Chinese Acupuncture in the Treatment for Chemotherapy-Induced Cognitive Impairment in Older Patients With Cancer: Protocol for a Randomized Controlled Trial

BACKGROUND

Older patients with cancer experience cognitive impairment and a series of neurocognitive symptoms known as chemobrain due to chemotherapy. Moreover, older populations are disproportionately affected by chemobrain and heightened negative mental health outcomes after cytotoxic chemical drug therapy. Chinese acupuncture is an emerging therapeutic option for chemotherapy-induced cognitive impairment in older patients with cancer, despite limited supporting evidence.

OBJECTIVE

Our study aims to directly contribute to the existing knowledge of this novel Chinese medicine mode in older patients with cancer enrolled at the Department of Oncology/Chinese Medicine, Nanjing First Hospital, China, thereby establishing the basis for further research.

METHODS

This study involves a 2-arm, prospective, randomized, assessor-blinded clinical trial in older patients with cancer experiencing chemobrain-related stress and treated with Chinese acupuncture from September 30, 2023, to December 31, 2025. We will enroll 168 older patients with cancer with clinically confirmed chemobrain. These participants will be recruited through screening by oncologists for Chinese acupuncture therapy and evaluation. Electroacupuncture will be performed by a registered practitioner of Chinese medicine. The electroacupuncture intervention will take about 30 minutes every session (2 sessions per week over 8 weeks). For the experimental group, the acupuncture points are mainly on the head, limbs, and abdomen, with a total of 6 pairs of electrically charged needles on the head, while for the control group, the acupuncture points are mainly on the head and limbs, with only 1 pair of electrically charged needles on the head.

RESULTS

Eligible participants will be randomized to the control group or the experimental group in 1:1 ratio. The primary outcome of this intervention will be the scores of the Montreal Cognitive Assessment. The secondary outcomes, that is, attentional function and working memory will be determined by the Digit Span Test scores. The quality of life of the patients and multiple functional assessments will also be evaluated. These outcomes will be measured at 2, 4, 6, and 8 weeks after the randomization.

CONCLUSIONS

This efficacy trial will explore whether Chinese electroacupuncture can prevent chemobrain, alleviate the related symptoms, and improve the quality of life of older patients with cancer who are undergoing or are just going to begin chemotherapy. The safety of this electroacupuncture intervention for such patients will also be evaluated. Data from this study will be used to promote electroacupuncture application in patients undergoing chemotherapy and support the design of further real-world studies.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05876988; https://clinicaltrials.gov/ct2/show/NCT05876988.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/53853.

Senolytic treatment alleviates doxorubicin-induced chemobrain

Doxorubicin (Dox), a widely used treatment for cancer, can result in chemotherapy-induced cognitive impairments (chemobrain). Chemobrain is associated with inflammation and oxidative stress similar to aging. As such, Dox treatment has also been used as a model of aging. However, it is unclear if Dox induces brain changes similar to that observed during aging since Dox does not readily enter the brain. Rather, the mechanism for chemobrain likely involves the induction of peripheral cellular senescence and the release of senescence-associated secretory phenotype (SASP) factors and these SASP factors can enter the brain to disrupt cognition. We examined the effect of Dox on peripheral and brain markers of aging and cognition. In addition, we employed the senolytic, ABT-263, which also has limited access to the brain. The results indicate that plasma SASP factors enter the brain, activating microglia, increasing oxidative stress, and altering gene transcription. In turn, the synaptic function required for memory was reduced in response to altered redox signaling. ABT-263 prevented or limited most of the Dox-induced effects. The results emphasize a link between cognitive decline and the release of SASP factors from peripheral senescent cells and indicate some differences as well as similarities between advanced age and Dox treatment.

Chemobrain in blood cancers: How chemotherapeutics interfere with the brain's structure and functionality, immune system, and metabolic functions

Cancer treatment brings about a phenomenon not fully clarified yet, termed chemobrain. Its strong negative impact on patients' well-being makes it a trending topic in current research, interconnecting many disciplines from clinical oncology to neuroscience. Clinical and animal studies have often reported elevated concentrations of proinflammatory cytokines in various types of blood cancers. This inflammatory burst could be the background for chemotherapy-induced cognitive deficit in patients with blood cancers. Cancer environment is a dynamic interacting system. The review puts into close relationship the inflammatory dysbalance and oxidative/nitrosative stress with disruption of the blood-brain barrier (BBB). The BBB breakdown leads to neuroinflammation, followed by neurotoxicity and neurodegeneration. High levels of intracellular reactive oxygen species (ROS) induce the progression of cancer resulting in increased mutagenesis, conversion of protooncogenes to oncogenes, and inactivation of tumor suppression genes to trigger cancer cell growth. These cell alterations may change brain functionality, as well as morphology. Multidrug chemotherapy is not without consequences to healthy tissue and could even be toxic. Specific treatment impacts brain function and morphology, functions of the immune system, and metabolism in a unique mixture. In general, a chemo-drug's effects on cognition in cancer are not direct and/or in-direct, usually a combination of effects is more probable. Last but not least, chemotherapy strongly impacts the immune system and could contribute to BBB disruption. This review points out inflammation as a possible mechanism of brain damage during blood cancers and discusses chemotherapy-induced cognitive impairment.

The Counter Effect of Exercise on Cisplatin-Induced Cognitive and Proliferation Impairments

Background Cisplatin, a widely used chemotherapeutic agent, offers therapeutic benefits for cancer treatment but often leads to adverse effects on neurogenesis and oxidative stress, causing cognitive impairment. Concurrent physical activity has been proposed as a potential strategy to counteract these side effects. This study aimed to investigate the impact of physical exercise on cisplatin-induced cognitive impairment in a mouse model. Methods Adult male mice (n=45) were divided into three groups: control, cisplatin-treated (2.3 mg/kg), and exercise/cisplatin. Cisplatin was administered intraperitoneally over one month, while the exercise/cisplatin group underwent moderate-intensity exercise alongside cisplatin treatment. Spatial memory was evaluated using the novel object recognition (NOR) task, and hippocampal proliferation and oxidative stress were examined using Ki-67 and glutathione peroxidase (GPx) immunohistochemistry (IHC) staining, respectively. Statistical analyses were performed using the GraphPad Prism 4.0 software (GraphPad Software, San Diego, CA). Results The cisplatin-treated mice exhibited significantly lower preference index (PI) scores in the NOR task compared to the control (p<0.001) and exercise/cisplatin (p<0.001) groups. IHC staining revealed impaired hippocampal proliferation and increased oxidative stress in the cisplatin-treated group relative to the control and exercise/cisplatin groups. The introduction of a moderate-intensity exercise protocol appeared to mitigate the decline in hippocampal proliferation and oxidative damage induced by cisplatin. Additionally, cisplatin-treated mice experienced weight loss, while exercise attenuated this effect. Conclusion Cisplatin treatment resulted in decreased memory, hippocampal proliferation, and weight loss in mice. Concurrent moderate-intensity exercise seemed to alleviate these effects, suggesting a potential role for physical activity in ameliorating cisplatin-induced cognitive decline. This study underscores the importance of incorporating exercise as a complementary strategy to enhance cognitive outcomes in cancer patients undergoing cisplatin treatment.

The selective cyclooxygenase-2 inhibitor NS398 ameliorates cisplatin-induced impairments in mitochondrial and cognitive function

Chemobrain is a condition that negatively affects cognition in cancer patients undergoing active chemotherapy, as well as following chemotherapy cessation. Chemobrain is also known as chemotherapy-induced cognitive impairment (CICI) and has emerged as a significant medical contingency. There is no therapy to ameliorate this condition, hence identification of novel therapeutic strategies to prevent CICI is of great interest to cancer survivors. Utilizing the platinum-based chemotherapy cisplatin in an investigative approach for CICI, we identified increased expression of cyclooxygenase-2 (COX-2) and prostaglandin E2 (PGE2) in the adult mouse hippocampus, and in human cortical neuron cultures derived from induced pluripotent stem cells (iPSCs). Notably, administration of NS398, a selective COX-2 inhibitor, prevented CICI in vivo without negatively affecting the antitumor efficacy of cisplatin or potentiating tumor growth. Given that dysfunctional mitochondrial bioenergetics plays a prominent role in CICI, we explored the effects of NS398 in cisplatin-induced defects in human cortical mitochondria. We found that cisplatin significantly reduces mitochondrial membrane potential (MMP), increases matrix swelling, causes loss of cristae membrane integrity, impairs ATP production, as well as decreases cell viability and dendrite outgrowth. Pretreatment with NS398 in human cortical neurons attenuated mitochondrial dysfunction caused by cisplatin, while improving cell survival and neurite morphogenesis. These results suggest that aberrant COX-2 inflammatory pathways may contribute in cisplatin-induced mitochondrial damage and cognitive impairments. Therefore, COX-2 signaling may represent a viable therapeutic approach to improve the quality of life for cancer survivors experiencing CICI.

"Is My Brain Ever Going to Work Fully Again?": Challenges and Needs of Cancer Survivors with Persistent Cancer-Related Cognitive Impairment

Many cancer survivors experience cognitive impairments that impact memory, concentration, speed of information processing, and decision making. These impairments, collectively known as cancer-related cognitive impairments (CRCIs), are a key domain of unmet needs and can significantly impact a cancer survivor's identity and quality of life. However, there are no purpose-built, multi-domain, needs assessment tools specifically for CRCI. The development of such tools requires an in-depth understanding of cancer survivors' CRCI-specific challenges and associated needs. This study explored the challenges and associated needs of cancer survivors with persistent CRCI. An in-depth qualitative design using semi-structured interviews with (a) cancer survivors with perceived CRCI (n = 32) and (b) oncology health professionals (n = 19) was utilised. A reflexive thematic analysis of the interviews resulted in five overarching themes: (1) executing regular activities, (2) relational difficulties, (3) occupational functioning, (4) psychological distress, and (5) social functioning, as well as an additional informational needs domain. Ultimately, CRCI was found to directly produce a range of challenges that negatively, and persistently, impact cancer survivors' quality of life. Cancer survivors were also found to have a range of needs associated with these challenges. This research should be used to inform future challenges and needs assessment tools as well as treatment and supportive care priority areas directly relating to CRCI.

Intranasally Administered MSC-Derived Extracellular Vesicles Reverse Cisplatin-Induced Cognitive Impairment

Neurotoxic side effects of chemotherapy include deficits in attention, memory, and executive functioning. Currently, there are no FDA-approved therapies. In mice, cisplatin causes long-term cognitive deficits, white matter damage, mitochondrial dysfunction, and loss of synaptic integrity. We hypothesized that MSC-derived small extracellular vesicles (sEVs) could restore cisplatin-induced cognitive impairments and brain damage. Animals were injected with cisplatin intraperitoneally and treated with MSC-derived sEVs intranasally 48 and 96 h after the last cisplatin injection. The puzzle box test (PBT) and the novel object place recognition test (NOPRT) were used to determine cognitive deficits. Synaptosomal mitochondrial morphology was analyzed by transmission electron microscopy. Immunohistochemistry using antibodies against synaptophysin and PSD95 was applied to assess synaptic loss. Black-Gold II staining was used to quantify white matter integrity. Our data show that sEVs enter the brain in 30 min and reverse the cisplatin-induced deficits in executive functioning and working and spatial memory. Abnormalities in mitochondrial morphology, loss of white matter, and synaptic integrity in the hippocampus were restored as well. Transcriptomic analysis revealed upregulation of regenerative functions after treatment with sEVs, pointing to a possible role of axonal guidance signaling, netrin signaling, and Wnt/Ca²⁺ signaling in recovery. Our data suggest that intranasal sEV treatment could become a novel therapeutic approach for the treatment of chemobrain.

A neurotherapy protocol to remediate cognitive deficits after adjuvant chemotherapy: a pilot study

OBJECTIVES

Adjuvant chemotherapy for breast cancer is undeniably effective in increasing survival rates but many breast cancer survivors (BCS) exhibit side effects including nausea, fatigue, stress, and neurocognitive deficits, known as "chemobrain." This pilot study explored how neurotherapy, or EEG biofeedback, a non-pharmacological approach, improved neurocognitive, behavioral, and neurophysiological deficits associated with BCS who underwent chemotherapy.

METHODS

Subjects underwent 18 sessions of EEG biofeedback training, in which audio and visual feedback occurred with successful shifting of EEG patterns.

RESULTS

Quantitative EEG and assessment tests demonstrated neurophysiological, cognitive, and behavioral deficits in all nine subjects prior to training. EEG biofeedback resulted in significant improvements in neurophysiological, neurocognitive, and psychological functions in all nine subjects after training.

CONCLUSIONS

We propose that this intervention and related forms of EEG biofeedback have the potential to significantly alleviate common side effects of chemotherapy in BCS and therefore merits additional research attention.

Chemotherapy-Induced Cognitive Impairment

Terms such as "chemobrain" or "chemofog" may be familiar to many patients with cancer. Specific chemotherapy agents are known to cause chemotherapy-induced cognitive impairment (CICI). Interventions to prevent or redu.

Functional imaging of chemo-brain: usefulness of Nuclear Medicine in the fog coming after cancer

The impact of chemotherapy on brain functionality has been widely investigated from a clinical perspective and there is a consensus on a significant impairment of multiple cognitive domains affecting cancer patients after treatment. Nuclear medicine offers a variety of biomarkers for the evaluation of possible effects of chemotherapy on the brain and for depicting brain changes after chemotherapy treatment. This review aims to summarize the most relevant findings on brain imaging in patients treated with chemotherapy for the most common oncological diseases. The literature published to date offers exciting results with several radiolabeled compounds, from the more common imaging of glucose metabolism to neuroinflammation. In this review, a general overview of the literature concerning clinical features and the physiopathological basis of chemotherapy-related cognitive impairment is reported as well.

Nasal administration of mesenchymal stem cells prevents accelerated age-related tauopathy after chemotherapy in mice

BACKGROUND

There is increasing concern that cancer and cancer treatment accelerate aging and the associated cognitive decline. We showed recently that treatment of 9-month-old male mice with cisplatin causes cognitive deficits that are associated with formation of tau deposits in the hippocampus. Here we explored the capacity of mesenchymal stem cells (MSC) given via the nose to prevent age-related brain tau deposits. Moreover, we more closely examined the cellular distribution of this hallmark of accelerated brain aging in response to treatment of 9-month-old female and male mice with cisplatin.

RESULTS

We show that cisplatin induces tau deposits in the entorhinal cortex and hippocampus in both sexes. The tau deposits colocalize with syndecan-2. Astrocytes surrounding tau deposits have increased glial fibrillary acidic protein glial fibrillary acidic protein (GFAP) expression. Most of the cisplatin-induced tau deposits were located in microtubule associated protein-2 (MAP-2)⁺ neurons that were surrounded by aquaporin 4⁺ (AQP4)⁺ neuron-facing membrane domains of astrocytes. In addition, some tau deposits were detected in the perinuclear region of GFAP⁺ astrocytes and in CD31⁺ endothelial cells. There were no morphological signs of activation of ionized calcium binding adaptor molecule-1⁺ (Iba-1)⁺ microglia and no increases in brain cytokine production. Nasal administration of MSC at 48 and 96 hours after cisplatin prevented formation of tau deposits and normalized syndecan-2 and GFAP expression. Behaviorally, cisplatin-induced tau cluster formation was associated with reduced executive functioning and working/spatial memory and nasal administration of MSC at 48 and 96 hours after cisplatin prevented these cognitive deficits. Notably, delayed MSC administration (1 month after cisplatin) also prevented tau cluster formation and cognitive deficits, in both sexes.

CONCLUSION

In summary, nasal administration of MSC to older mice at 2 days or 1 month after completion of cisplatin treatment prevents the accelerated development of tau deposits in entorhinal cortex and hippocampus and the associated cognitive deficits. Since MSC are already in clinical use for many other clinical indications, developing nasal MSC administration for treatment of accelerated brain aging and cognitive deficits in cancer survivors should be feasible and would greatly improve their quality of life.

[Chemobrain - cognitive disorders after chemotherapy]

In recent years, more and more attention has been paid to the deterioration of cognitive functioning after the use of chemotherapy. The article presents the problems of cognitive disorders caused by chemotherapy in cancer patients. These deficits in scientific terminology are called chemobrain. Patients in particular indicate disorders of: longterm verbal memory and executive functions (planning, verbal fluency and working memory). This is confirmed by the results of neuroimaging studies. It has been observed that higher doses of cytostatics may contribute to the development of cognitive deficits. This article is a general introduction to the problems of chemobrain - the definition of the phenomenon and a discussion of neuroanatomical issues related to the influence of chemotherapy on the central nervous system. Moreover, the article tries to draw attention to the application of neuropsychological rehabilitation after chemotherapy.

Nicotinamide Mononucleotide Prevents Cisplatin-Induced Mitochondrial Defects in Cortical Neurons Derived from Human Induced Pluripotent Stem Cells

Background

Chemotherapy-induced cognitive impairment (CICI) is a neurotoxic side effect of chemotherapy that has yet to have an effective treatment.

Objective

Using cisplatin, a platinum-based chemotherapy together with excitatory cortical neurons derived from human induced pluripotent cells (iPSCs) to model of CICI, our recent study demonstrated that dysregulation of brain NAD+ metabolism contributes to cisplatin-induced impairments in neurogenesis and cognitive function, which was prevented by administration of the NAD+ precursor, nicotinamide mononucleotide (NMN). However, it remains unclear how cisplatin causes neurogenic dysfunction and the mechanism by which NMN prevents cisplatin-induced cognitive impairment. Given that mitochondrial dysfunction is thought to play a prominent role in age-related neurodegenerative disease and chemotherapy-induced neurotoxicity, we sought to explore if NMN prevents chemotherapy-related neurotoxicity by attenuating cisplatin-induced mitochondrial damage.

Results

We demonstrate that cisplatin induces neuronal DNA damage, increases generation of mitochondrial reactive oxygen species (ROS) and decreases ATP production, all of which are indicative of oxidative DNA damage and mitochondrial functional defects. Ultrastructural analysis revealed that cisplatin caused loss of cristae membrane integrity and matrix swelling in human cortical neurons. Notably, pretreatment with NMN prevents cisplatin-induced defects in mitochondria of human cortical neurons.

Conclusion

Our results suggest that increased mitochondrial oxidative stress and functional defects play key roles in cisplatin-induced neurotoxicity. Thus, NMN may be an effective therapeutic strategy to prevent cisplatin-induced deleterious effects on mitochondria, making this organelle a key factor in amelioration of cisplatin-induced cognitive impairments.

Piracetam as a Therapeutic Agent for Doxorubicin-Induced Cognitive Deficits by Enhancing Cholinergic Functions and Reducing Neuronal Inflammation, Apoptosis, and Oxidative Stress in Rats

Cancer chemotherapy is known to cause cognitive defects in patients. Our study investigated the effect of piracetam (PIRA; 200 or 400 mg/kg) against doxorubicin (DOX)-induced cognitive deficits in a rat model. The cognitive parameters were analyzed using elevated plus-maze, novel object recognition, and Y-maze tests. Acetylcholinesterase (AChE), neuroinflammatory mediators (cyclooxygenase-2 (COX-2), prostaglandin E2 (PGE2), nuclear factor-κB (NF-κB), tumor necrosis factor-alpha (TNF-α)), apoptotic proteins (B-cell lymphoma-2 (Bcl-2), Bcl2 associated X protein (Bax), cysteine aspartate specific protease-3 (caspase-3)), oxidative parameters (malondialdehyde (MDA), catalase (CAT), and glutathione (GSH)) were also determined in the brain. PIRA administration offered significant protection against DOX-induced cognitive deficits in all maze tests and restored cholinergic functions via a significant reduction in AChE levels. Additionally, PIRA suppressed DOX-induced neuroinflammatory mediators (COX-2, PGE2, NF-κB, and TNF-α), pro-apoptotic proteins (Bax and caspase-3), and oxidative stress (MDA). Besides, it facilitated antioxidant (CAT and GSH) levels. Hence, our study highlighted that the neuroprotective activity of PIRA against DOX-induced cognitive deficits can be linked to reductions of AChE levels, neuro-inflammatory mediators, pro-apoptotic proteins, and oxidative stress.

Neurological Complications of Conventional and Novel Anticancer Treatments

Various neurological complications, affecting both the central and peripheral nervous system, can frequently be experienced by cancer survivors after exposure to conventional chemotherapy, but also to modern immunotherapy. In this review, we provide an overview of the most well-known adverse events related to chemotherapy, with a focus on chemotherapy induced peripheral neurotoxicity, but we also address some emerging novel clinical entities related to cancer treatment, including chemotherapy-related cognitive impairment and immune-mediated adverse events. Unfortunately, efficacious curative or preventive treatment for all these neurological complications is still lacking. We provide a description of the possible mechanisms involved to drive future drug discovery in this field, both for symptomatic treatment and neuroprotection.

Perioperative considerations in patients with chemotherapy-induced cognitive impairment: a narrative review

Patients with cancer may suffer from a decline in their cognitive function after various cancer therapies, including surgery, radiation, and chemotherapy, and in some cases, this decline in cognitive function persists even years after completion of treatment. Chemobrain or chemotherapy-induced cognitive impairment, a well-established clinical syndrome, has become an increasing concern as the number of successfully treated cancer patients has increased significantly. Chemotherapy-induced cognitive impairment can originate from direct neurotoxicity, neuroinflammation, and oxidative stress, resulting in alterations in grey matter volume, white matter integrity, and brain connectivity. Surgery has been associated with exacerbating the inflammatory response associated with chemotherapy and predisposes patients to develop postoperative cognitive dysfunction. As the proportion of patients living longer after these therapies increases, the magnitude of impact and growing concern of post-treatment cognitive dysfunction in these patients has also come to the fore. We review the clinical presentation, potential mechanisms, predisposing factors, diagnostic methods, neuropsychological testing, and imaging findings of chemotherapy-induced cognitive impairment and its intersection with postoperative cognitive dysfunction.

Chemobrain, Olfactory and Lifestyle Assessment in Onco-Geriatrics: Sex-Mediated Differences between Chemotherapy and Immunotherapy

A possible link between chemotherapy and cognitive impairment has been identified. In the literature, this condition is usually called chemobrain and can mostly affect some memory domain but can lead also to other cognitive impairments. Olfaction, which is known to be linked with cognitive domain and the nociception system, can also be affected by chemotherapy. The aim of this study was to investigate the main cognitive and olfactory abilities and the functional and nutritional state of a cohort of chemotherapy and immunotherapy onco-geriatric patients and control geriatrics subjects. Cognitive, olfactory, geriatric and nutritional assessments were performed through the Mini Mental State Examination (MMSE), Sniffin' Sticks Screening 12, G8 test and a questionnaire on the adherence of the Mediterranean diet, respectively. Our findings show a gender effect on the MMSE. Overall results indicate more pronounced impairments both at the cognitive and frailty level regardless of the type of therapy. On the other hand, the Sniffin' Sticks performances highlight a significant decrease in olfactory perception ability of subjects following immunotherapy. Significant correlations between olfactory performance and MMSE and G8 scores were also found, as well as between MMSE and G8 measures.

Modulation of mitochondrial dynamics rescues cognitive function in rats with 'doxorubicin-induced chemobrain' via mitigation of mitochondrial dysfunction and neuroinflammation

Doxorubicin (DOX), an effective, extensively used chemotherapeutic drug, can cause cognitive deterioration in cancer patients. The associated debilitating neurological sequelae are referred to as chemobrain. Our recent work demonstrated that Dox treatment resulted in an imbalance in mitochondrial dynamics, ultimately culminating in cognitive decline in rats. Therefore, in this study, we aim to explore the therapeutic efficacy of a pharmacological intervention, which modulates mitochondrial dynamics using a potent mitochondrial fission inhibitor (Mdivi-1) and mitochondrial fusion promoter (M1) against Dox-induced chemobrain. In the study, male Wistar rats were randomly assigned to receive either normal saline solution or six doses of Dox (3 mg·kg-1 ) via intraperitoneal injection. Then, the Dox-treated rats were intraperitoneally given either 1% DMSO as the vehicle, Mdivi-1 (1.2 mg·kg-1 ), M1 (2 mg·kg-1 ), or a combined treatment of Mdivi-1 and M1 for 30 consecutive days. Long-term learning and memory were evaluated using the novel object location task and novel object recognition task. Following euthanasia, the rat brains were dissected to enable further molecular investigation. We demonstrated that long-term treatment with mitochondrial dynamic modulators suppressed mitochondrial fission in the hippocampus following Dox treatment, leading to an improvement in brain homeostasis. Mitochondrial dynamic modulator treatments restored cognitive function in Dox-treated rats by attenuating neuroinflammation, decreasing oxidative stress, preserving synaptic integrity, reducing potential Alzheimer's related lesions, and mitigating both apoptosis and necroptosis following Dox administration. Together, our findings suggested that mitochondrial dynamics modulators protected against Dox-induced cognitive impairment by rebalancing mitochondrial homeostasis and attenuating both oxidative and inflammatory insults.

Neural correlates in functional brain mapping among breast cancer survivors receiving different chemotherapy regimens: a qEEG/HEG-based investigation

BACKGROUND

Post-chemotherapy cognitive impairment commonly known as 'chemobrain' or 'chemofog' is a well-established clinical disorder affecting various cognitive domains including attention, visuospatial working memory, executive function, etc. Although several studies have confirmed the chemobrain in recent years, scant experiments have evaluated the potential neurotoxicity of different chemotherapy regimens and agents. In this study, we aimed to evaluate the extent of attention deficits, one of the commonly affected cognitive domains, among breast cancer patients treated with different chemotherapy regimens through neuroimaging techniques.

METHODS

Breast cancer patients treated with two commonly prescribed chemotherapy regimens, Adriamycin, Cyclophosphamide and Taxol and Taxotere, Adriamycin and Cyclophosphamide, and healthy volunteers were recruited. Near-infrared hemoencephalography and quantitative electroencephalography assessments were recorded for each participant at rest and during task performance to compare the functional cortical changes associated with each chemotherapy regimen.

RESULTS

Although no differences were observed in hemoencephalography results across groups, the quantitative electroencephalography analysis revealed increased power of high alpha/low beta in left fronto-centro-parietal regions involved in dorsal and ventral attention networks in the Adriamycin, Cyclophosphamide and Taxol-treated group compared with the Taxotere, Adriamycin and Cyclophosphamide and control group. The Adriamycin, Cyclophosphamide and Taxol-treated cases had the highest current source density values in dorsal attention network and ventral attention network and ventral attention network-related centers in 10 and 15 Hz associated with the lowest Z-scored Fast Fourier Transform coherence in the mentioned regions.

CONCLUSIONS

The negatively affected neurocognitive profile in breast cancer patients treated with the Adriamycin, Cyclophosphamide and Taxol regimen proposes presumably neurotoxic sequelae of this chemotherapy regimen as compared with the Taxotere, Adriamycin and Cyclophosphamide regimen.

COMT rs737865 mediates chemobrain in breast cancer patients with various levels of Ki-67

Previous findings have indicated that catechol-O-methyltransferase (COMT) may be a genetic risk factor for chemobrain. However, the mediation of chemobrain by COMT polymorphisms in breast cancer patients with various levels of Ki-67 remains unknown. The current research assessed the genetic risk across COMT genotypes for chemobrain in breast cancer patients with various levels of Ki-67. Breast cancer patients (65 with Ki-67<14%, 75 with Ki-67>14%) completed cognitive tests before and after adjuvant chemotherapy, and three single-nucleotide polymorphisms (SNPs) of COMT (rs165599, rs4680, rs737865) were genotyped from peripheral blood. Lower cognitive test results in breast cancer patients were displayed in those before chemotherapy. Furthermore, the event-based prospective memory (EBPM) scores of patients in the Ki-67>14% group were worse than those in the patients in the Ki-67<14% group after chemotherapy (z=-7.51, P<0.01), but the time-based prospective memory (TBPM) scores of the two groups were not significantly different. The COMT rs737865 A/G genotype was associated with memory protection (codominant model: adjusted odds ratio (OR)=0.135, 95% CI=0.026-0.706, P=0.018), and A/G genotype carriers exhibited better performance on the EBPM test than the A/A genotype. Levels of Ki-67 were likely to be associated with EBPM decline in breast cancer patients. Taken together, COMT rs737865 polymorphisms are a potential genetic risk factor for chemobrain in breast cancer patients with various levels of Ki-67.

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.

Cyclophosphamide and epirubicin induce high apoptosis in microglia cells while epirubicin provokes DNA damage and microglial activation at sub-lethal concentrations

Chemotherapy Related Cognitive Impairment (CRCI), also called chemobrain, diminishes cancer patient's life quality. Breast cancer (BC) patients have been described to be importantly affected, however, the mechanism leading to CRCI has not been fully elucidated. Recent research proposes microglia as the main architect of CRCI, thus dysregulations in these cells could trigger CRCI. The aim of this research was to evaluate the effects of two drugs commonly used against breast cancer, cyclophosphamide (CTX) and epirubicin (EPI), on the microglia cell line SIM-A9, using the BC cell line, 4T1, as a control. Our results show that CTX and EPI decrease microglia-cell viability and increase cell death on a concentration-dependent manner, being 5 and 2 times more cytotoxic to microglia cell line than to breast cancer 4T1cells, respectively. Both chemotherapies induce cell cycle arrest and a significant increase in p53, p16 and γ-H2AX in breast cancer and microglia cells. Furthermore, mitochondrial membrane potential (ΔΨm) diminishes as cell death increases, and both chemotherapies induce reactive oxygen species (ROS) production on SIM-A9 and 4T1. Moreover, caspase activation increases with treatments and its pharmacological blockade inhibits CTX and EPI induced-cell death. Finally, low concentrations of CTX and EPI induce γ-H2AX, and EPI induces cytokine release, NO production and Iba-1 overexpression. These findings indicate that microglia cells are more sensitive to CTX and EPI than BC cells and undergo DNA damage and cell cycle arrest at very low concentrations, moreover EPI induces microglia activation and a pro-inflammatory profile.

HDAC6 inhibition reverses long-term doxorubicin-induced cognitive dysfunction by restoring microglia homeostasis and synaptic integrity

Breast cancer is the most common female malignancy in both the developed and developing world. Doxorubicin is one of the most commonly used chemotherapies for breast cancer. Unfortunately, up to 60% of survivors report long-term chemotherapy-induced cognitive dysfunction (CICD) characterized by deficits in working memory, processing speed and executive function. Currently, no therapeutic standard for treating CICD exists. Here, we hypothesized that treatment with a blood-brain barrier permeable histone deacetylase 6 (HDAC6) inhibitor can successfully reverse long-term doxorubicin-induced cognitive dysfunction. Methods: The puzzle box test and novel object/place recognition test were used to assess cognitive function following a therapeutic doxorubicin dosing schedule in female mice. Mitochondrial function and morphology in neuronal synaptosomes were evaluated using the Seahorse XF24 extracellular flux analyzer and transmission electron microscopy, respectively. Hippocampal postsynaptic integrity was evaluated using immunofluorescence. Hippocampal microglia phenotype was determined using advanced imaging techniques and single-nucleus RNA sequencing. Results: A 14-day treatment with a blood-brain barrier permeable HDAC6 inhibitor successfully reversed long-term CICD in the domains of executive function, working and spatial memory. No significant changes in mitochondrial function or morphology in neuronal synaptosomes were detected. Long-term CICD was associated with a decreased expression of postsynaptic PSD95 in the hippocampus. These changes were associated with decreased microglial ramification and alterations in the microglia transcriptome that suggest a stage 1 disease-associated microglia (DAM) phenotype. HDAC6 inhibition completely reversed these doxorubicin-induced alterations, indicating a restoration of microglial homeostasis. Conclusion: Our results show that decreased postsynaptic integrity and a neurodegenerative microglia phenotype closely resembling stage 1 DAM microglia contribute to long-term CICD. Moreover, HDAC6 inhibition shows promise as an efficacious pharmaceutical intervention to alleviate CICD and improve quality of life of breast cancer survivors.

Research advances on how metformin improves memory impairment in "chemobrain"

Cognitive impairment caused by chemotherapy, referred to as “chemobrain,” is observed in approximately 70% of cancer survivors. However, it is not completely understood how chemotherapy induces cognitive dysfunction, and clinical treatment strategies for this problem are lacking. Metformin, used as a first-line treatment for type 2 diabetes mellitus, is reported to reduce the effects of chemobrain. Recently, several studies have examined the effect of metformin in rescuing chemobrain. This review discusses recent clinical/preclinical studies that addressed some mechanisms of chemobrain and evaluates the effect of metformin in rescuing chemobrain and its potential mechanisms of action.

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.

Protective effects of cerebrolysin against chemotherapy (carmustine) induced cognitive impairment in Albino mice

Chemotherapy-induced cognitive impairment (CICI) comprises different neurological problems, including difficulty in learning new things, concentrating and making decisions that affect daily life activities. Clinical reports indicate that around 70% of cancer patients receiving chemotherapy suffer from cognitive impairment. The purpose of the present study is to examine the effects of widely used anticancer medication (Carmustine) on cognitive function using mice model and investigation of the neuroprotective effects of Cerebrolysin (CBN). Cerebrolysin (CBN) is a mixture of several neurotrophic factors and active peptides with anti-inflammatory, antioxidant, and neuroprotective actions. Our study aimed to establish a mice model of Carmustine (BCNU)-induced cognitive deficits and determine the protective effects of CBN. BCNU (10 mg/kg, i.v.) was administered to mice for 28 days, and behavioral parameters were measured on a weekly basis. CBN (44 and 88 mg/kg, i.p.) was administered daily from day 1 to 28 to BCNU treatment mice. All animals were sacrificed on day 29 and brain hippocampus tissues were used for biochemical, neuroinflammatory, neurotransmitters analysis. BCNU administration animals showed impaired cognition and memory, confirmed from behavioral analysis. Further, BCNU increased oxidative stress, inflammatory cytokines release and altered neurotransmitters concentration as compared to the control group (p < 0.01). However, mice treated with CBN (44 and 88 mg/kg, i.p.) significantly and dose-dependently improved cognitive functions, reduced oxidative stress markers, inflammatory cytokines and restored neurotransmitters concentration as compared to BCNU administered mice (p < 0.05). The finding of current study suggested that CBN could be the promising compound to reverse cognitive impairment associated with use of chemotherapy.

Chemotherapy-related subjective cognitive impairment in breast cancer patients in semi-rural South Africa

Background

Breast cancer is the most commonly diagnosed cancer amongst women worldwide. Whilst current evidence indicates the therapeutic benefits from the use of chemotherapy, self-perceived cognitive difficulties emerged as a frequent occurrence during and after chemotherapy treatment in breast cancer patients.

Aim

The current study sought to investigate self-perceived cognitive impairment in a group of breast cancer patients in semi-rural South Africa.

Setting

The patients were recruited from an outpatient oncology clinic at a semi-rural, tertiary academic hospital in Gauteng, South Africa.

Methods

In a randomised, quantitative, time-based series study, 30 female patients aged 21–60 years (mean age = 50 years) diagnosed with stages II and III breast cancer on CMF (cyclophosphamide, methotrexate, fluorouracil) (n = 10) and FAC (fluorouracil, adriamycin, cyclophosphamide) (n = 20) chemotherapy regimens, completed the self-reported Functional Assessment of Cancer Therapy-Cognition (Fact-Cog) test as a measure of subjective cognitive functioning at three points during the course of treatment (T₀, T₁, T₂).

Results

The results of the paired sample t-tests showed the scores on the Fact-Cog test confirmed significant cognitive decline for both treatment groups from baseline (T₀) to completion (T₂) of chemotherapy; CMF group, t (9) = 2.91, p = 0.017 and the FAC group t (19) = 4.66, p < 0.001.

Conclusion

This study confirms that self-reported subjective cognitive impairment is common in breast cancer patients who received chemotherapy in a sample of South African patients. The results have implications for the overall care of cancer patients.

Contribution

The context-based knowledge engendered by the current study is expected to augment the continuum of care for breast cancer patients.

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

BACKGROUND

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

CONCLUSION

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

Cognitive Effects and Depression Associated With Taxane-Based Chemotherapy in Breast Cancer Survivors: A Meta-Analysis

Purpose: This meta-analysis provides a longitudinal assessment of depression and cognitive impairment induced by taxane-based chemotherapy in women with breast cancer after 6 months of treatment. We highlighted the incidence and prevalence, the cognitive pattern in neuropsychological studies, and the relationship between chemotherapy-induced cognitive impairment and different risk factors. We estimated the effect sizes on each cognitive domain and differentiated effect sizes by each method of comparison of effects (i.e., baseline data, or control groups). Methods: The databases MEDLINE and Embase were searched for publications about taxane-related cognitive changes in patients with breast cancer published from 1980 to 2019. Cross-sectional and self-reported outcomes studies were excluded except for the depression item. Included studies were assessed for risk of bias with the Newcastle-Ottawa Scale. We estimated effect sizes for each cognitive domain and differentiated effect sizes by each method of comparison of effects. The review is reported in compliance with the PRISMA Statement; it was registered prospectively in PROSPERO as CRD42020163255. Results: Eleven studies meeting the criteria were analyzed, which resulted in a sample of 1,057 patients with breast cancer who received chemotherapy including 820 patients (77%) who received taxane-based chemotherapy. Attention and concentration, depression, and executive function domains had significant chemotherapy-induced impairment across all comparison types. Statistically significant improvement was found in language and verbal memory when comparing chemotherapy patients' test scores with baseline or matched controls. Taxane-based chemotherapy had a non-significant effect on processing speed, visual memory, visuospatial, and motor function domains. Conclusions: The occurrence of chemotherapy-induced cognitive impairment 6 months or more after the course of treatment in people with breast cancer is frequent in the domains of attention, executive function, and depression. Other domains appear stable or improve with time after treatment cessation.

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.

Redox imbalance induced by docetaxel in the neuroblastoma SH-SY5Y cells: a study of docetaxel-induced neuronal damage

Objectives

In cancer survivors, chemotherapy-associated adverse neurological effects are described as side effects in non-targeted tissue. We investigated the role of redox-imbalance in neuronal damage by a relative low dose of Docetaxel (DTX).

Methods

The neuroblastoma cells (SH-SY5Y cells) were exposed to DTX at a dose of 1.25 nM for 6 h. Antioxidant defenses (i.e. ascorbic acid, glutathione, and catalase) and lipid oxidation products (i.e. F₂-isoprostanes) were evaluated. To investigate cell ultrastructure and tubulin localisation, transmission electron microscopy (TEM) and immunofluorescence techniques were applied.

Results

In the SH-SY5Y cells, DTX induced a significant reduction of total glutathione (P < 0.001) and ascorbic acid (P < 0.05), and an increase in both total F₂-Isoprostanes (P < 0.05) and catalase activity (P < 0.05), as compared to untreated cells. Additionally, TEM showed a significant increase in cells with apoptotic characteristics. Immunolocalisation of tubulin showed a compromised cytoskeletal organisation.

Discussion

The investigated sublethal dose of DTX, to which non-targeted cells may be exposed throughout the duration of chemotherapy treatment, induces a redox imbalance resulting in a specific modulation of the antioxidant response. This study provides new insights into DTX-induced cellular mechanisms useful for evaluating whether the concomitant use of antioxidants associated with chemotherapy mitigates chemotherapy side effects in cancer survivors.

Beta-Caryophyllene, a CB2R Selective Agonist, Protects Against Cognitive Impairment Caused by Neuro-inflammation and Not in Dementia Due to Ageing Induced by Mitochondrial Dysfunction

BACKGROUND

Dementia is a neurodegenerative disorder majorly evidenced by cognitive impairment. Although there are many types of dementia, the common underlying etiological factors in all the types are neuro-inflammation or aging induced apoptosis. β-caryophyllene, a cannabinoid type-2 receptor agonist, has been reported to have promising neuroprotective effects in cerebral ischemia and neuro-inflammation.

OBJECTIVE

In the present study, we evaluated the effects of β-caryophyllene against animal models of dementia whose etiology mimicked neuro-inflammation and aging.

METHODS

Two doses (50 and 100 mg/kg of body weight) of β-caryophyllene given orally were tested against AlCl₃-induced dementia in male Sprague Dawley (SD) rats using the Morris water maze test. Subsequently, the effect of the drug was assessed for episodic memory in female SD rats using novel object recognition task in doxorubicin-induced neuro-inflammation and chemobrain model. Moreover, its effects were evaluated in D-galactose-induced mitochondrial dysfunction leading to dementia.

RESULTS

β-caryophyllene, at both doses, showed significant improvement in memory when assessed using parameters like target quadrant entries, escape latency and path efficiency in the Morris water maze test for spatial memory. In the doxorubicin-induced chemobrain model, β-caryophyllene at 100 mg/kg significantly elevated acetylcholinesterase and catalase levels and lowered lipid peroxidation compared to the disease control. In the novel object recognition task, β-caryophyllene at 100 mg/kg significantly improved recognition index and discrimination index in the treated animals compared to the disease control, with a significant increase in catalase and a decrease in lipid peroxidation in both hippocampus and frontal cortex. However, in the D-galactose-induced mitochondrial dysfunction model, β-caryophyllene failed to show positive effects when spatial memory was assessed. It also failed to improve D-galactose-induced diminished mitochondrial complex I and II activities.

CONCLUSION

Hence, we conclude that β-caryophyllene at 100 mg/kg protects against dementia induced by neuro-inflammation with no effect on neuronal aging induced by mitochondrial dysfunction.

Breast Cancer, Alzheimer's Disease, and APOE4 Allele in the UK Biobank Cohort

Background:

Cognitive problems are common in breast cancer patients. The apolipoprotein E4 (APOE4) gene, a risk factor for Alzheimer’s disease (AD), may be associated with cancer-related cognitive decline.

Objective:

To further evaluate the effects of the APOE4 allele, we studied a cohort of patients from the UK Biobank (UKB) who had breast cancer; some also had AD.

Methods:

Our analysis included all subjects with invasive breast cancer. Single nucleotide polymorphism (SNP) data for rs 429358 and rs 7412 was used to determine APOE genotypes. Cognitive function as numeric memory was assessed with an online test (UKB data field 20240).

Results:

We analyzed data from 2,876 women with breast cancer. Of the breast cancer subjects, 585 (20%) carried the APOE4 allele. Numeric memory scores were significantly lower in APOE4 carriers and APOE4 homozygotes than non-carriers (p = 0.046). 34 breast cancer subjects (1.1%) had AD. There was no significant difference in survival among genotypes ɛ3/ɛ3, ɛ3/ɛ4, and ɛ4/ɛ4.

Conclusion:

UKB data suggest that cognitive problems in women with breast cancer are, for the most part, mild, compared with other sequelae of the disease. AD, the worst cognitive problem, is relatively rare (1.1%) and, when it occurs, APOE genotype has little impact on survival.

Nasal administration of mitochondria reverses chemotherapy-induced cognitive deficits

Up to seventy-five percent of patients treated for cancer suffer from cognitive deficits which can persist for months to decades, severely impairing quality of life. Although the number of cancer survivors is increasing tremendously, no efficacious interventions exist. Cisplatin, most commonly employed for solid tumors, leads to cognitive impairment including deficits in memory and executive functioning. We recently proposed deficient neuronal mitochondrial function as its underlying mechanism. We hypothesized nasal administration of mitochondria isolated from human mesenchymal stem cells to mice, can reverse cisplatin-induced cognitive deficits. Methods: Puzzle box, novel object place recognition and Y-maze tests were used to assess the cognitive function of mice. Immunofluorescence and high-resolution confocal microscopy were employed to trace the nasally delivered mitochondria and evaluate their effect on synaptic loss. Black Gold II immunostaining was used to determine myelin integrity. Transmission electron microscopy helped determine mitochondrial and membrane integrity of brain synaptosomes. RNA-sequencing was performed to analyse the hippocampal transcriptome. Results: Two nasal administrations of mitochondria isolated from human mesenchymal stem cells to mice, restored executive functioning, working and spatial memory. Confocal imaging revealed nasally delivered mitochondria rapidly arrived in the meninges where they were readily internalized by macrophages. The administered mitochondria also accessed the rostral migratory stream and various other brain regions including the hippocampus where they colocalized with GFAP+ cells. The restoration of cognitive function was associated with structural repair of myelin in the cingulate cortex and synaptic loss in the hippocampus. Nasal mitochondrial donation also reversed the underlying synaptosomal mitochondrial defects. Moreover, transcriptome analysis by RNA-sequencing showed reversal of cisplatin-induced changes in the expression of about seven hundred genes in the hippocampus. Pathway analysis identified Nrf2-mediated response as the top canonical pathway. Conclusion: Our results provide key evidence on the therapeutic potential of isolated mitochondria - restoring both brain structure and function, their capability to enter brain meninges and parenchyma upon nasal delivery and undergo rapid cellular internalization and alter the hippocampal transcriptome. Our data identify nasal administration of mitochondria as an effective strategy for reversing chemotherapy-induced cognitive deficits and restoring brain health, providing promise for the growing population of both adult and pediatric cancer survivors.

Plasticity in bilateral hippocampi after a 3-month physical activity programme in lung cancer patients

BACKGROUND AND PURPOSE

Cancer treatments have deleterious effects on both brain structure and the cognition of lung cancer patients. Physical activity (PA) has beneficial effects on the cognition of healthy adults by eliciting brain plasticity, especially on the medial temporal lobe (hippocampus). Therefore, the aim was to study the neuroprotective effects of a 3-month PA programme (PAP) on the brain structure and cognitive performance of lung cancer patients.

METHODS

Twelve patients (seven non-small-cell lung cancer [NSCLC] patients following chemotherapy, five small-cell lung cancer [SCLC] patients following chemotherapy and prophylactic cranial irradiation) agreed to complete the PAP and underwent baseline and 3-month (post-PAP) brain magnetic resonance imaging and neuropsychological evaluations (PAP group). Twelve lung cancer patients (seven NSCLC, five SCLC; non-PAP group) and 12 healthy sex-, age- and education-matched controls were recruited and completed two evaluations separated by the same amount of time. A region of interest voxel-based morphometry analysis focused on bilateral hippocampi was performed.

RESULTS

Physical activity programme patients presented greater grey matter volume (GMV) across time in both hippocampi. Moreover, it was observed that SCLC patients in both the PAP and non-PAP groups presented a time-dependent GMV loss in bilateral hippocampi that was not significant in NSCLC patients. Importantly, the PA intervention decreased the magnitude of that GMV loss, becoming thus especially beneficial at the brain structural level for SCLC patients.

CONCLUSIONS

Our study demonstrates, using a neuroimaging approach for the first time, that PA is able to stop the deleterious effects of systemic chemotherapy and brain radiation on brain structures of the lung cancer population, especially in SCLC patients.

Hippocampal neural stem cells facilitate access from circulation via apical cytoplasmic processes

Blood vessels (BVs) are considered an integral component of neural stem cells (NSCs) niches. NSCs in the dentate gyrus (DG(have enigmatic elaborated apical cellular processes that are associated with BVs. Whether this contact serves as a mechanism for delivering circulating molecules is not known. Here we uncovered a previously unrecognized communication route allowing exclusive direct access of blood-borne substances to hippocampal NSCs. BBB-impermeable fluorescent tracer injected transcardially to mice is selectively uptaken by DG NSCs within a minute, via the vessel-associated apical processes. These processes, measured >30 nm in diameter, establish direct membrane-to-membrane contact with endothelial cells in specialized areas of irregular endothelial basement membrane and enriched with vesicular activity. Doxorubicin, a brain-impermeable chemotherapeutic agent, is also readily and selectively uptaken by NSCs and reduces their proliferation, which might explain its problematic anti-neurogenic or cognitive side-effect. The newly-discovered NSC-BV communication route explains how circulatory neurogenic mediators are 'sensed' by NSCs.

Neural correlates of working memory function in pediatric cancer survivors treated with chemotherapy: an fMRI study

The goal of this study is to investigate the neural correlates of working memory function associated with chemotherapy in pediatric cancer survivors using event-related functional MRI (fMRI) analysis. Fifteen pediatric cancer survivors treated with chemotherapy and 15 healthy controls were studied. Blood oxygenation level dependent (BOLD) fMRI was acquired. A visual n-back task was used to test working memory function during the fMRI scan. Responses were recorded via an MRI compatible button box for analysis. fMRI scans were analyzed using statistical parametric mapping software. All statistics were corrected for multiple comparisons by false discovery rate, with p < 0.05 as significance. Patients however gave more incorrect responses (p < 0.05), more no responses (p < 0.05), and longer response times (p < 0.05) compared with healthy controls. Correct responses generated significantly lower BOLD responses in the posterior cingulate for pediatric cancer survivors compared with controls (p < 0.05). Incorrect responses generated significantly greater BOLD responses in the angular gyrus in survivors (p < 0.05), and no response trials generated greater BOLD responses within the superior parietal lobule (p < 0.05) compared with controls. Working memory impairment appears to be due to an inability to manipulate information and to retrieve information from memory. The ability to delineate the affected neural circuits associated with chemotherapy-induced cognitive impairment could inform treatment strategies, identify patients at high risk of developing cognitive deficits, and pre-emptively tailor behavioral enrichment to overcome specific cognitive deficits.

The Effect of Theracurmin on Cognitive Function in an Older Patient with Chemobrain

Chemobrain is one of the problems that may arise during or after treatment and there is currently no specific treatment for this condition. Our case was a 76-year-old female patient who presented to our clinic with complaints of forgetfulness that did not affect daily living activities for the last year. Breast cancer was diagnosed in 2013 and she has been receiving anastrozole treatment for 6 years after local mass excision surgery and radiotherapy. After a comprehensive geriatric evaluation, cognitive impairment due to systemic cancer therapy was detected and treatment was started with Theracurmin 90 mg twice a day therapy. After 3-months of Theracurmin therapy, she had no cognitive improvement during the follow-up. This case report demonstrated that Theracurmin treatment may be a new option for chemobrain.

A Bibliometric Review of Publications on Oxidative Stress and Chemobrain: 1990-2019

Oxidative stress is considered one of the possible mechanisms behind chemobrain or the cognitive dysfunction persistent after chemotherapy treatment. Breast cancer patients have reported chemobrain symptoms since the 1990s. In this present bibliometric review, we employed the VOSviewer tool to describe the existing landscape on literature concerning oxidative stress, breast cancer chemotherapies, and chemobrain. As of 2019, 8799 papers were listed in the Web of Science database, with more than 900 papers published each year. As expected, terms relating to oxidative stress, mitochondria, breast cancer, and antioxidants have occurred very often in the literature throughout the years. In recent years, there has been an increase in the occurrence of terms related to nanomedicine. Only within the last decade do the keywords 'brain', 'blood-brain barrier', and 'central nervous system' appear, reflecting an increased interest in chemobrain. China has become the most prolific producer of oxidative stress and chemotherapy related papers in the last decade followed by the USA and India. In conclusion, the subject of oxidative stress as a mechanism behind chemotherapies' toxicities is an active area of research.

Effect of Metformin on Doxorubicin-Induced Memory Dysfunction

Doxorubicin (DOX) is widely used to treat many types of cancer; however, it is associated with chemotherapy-related complications such as cognitive dysfunction, known as chemobrain. Chemobrain affects up to 75% of cancer survivors, and there are currently no available therapeutic options. This study aims to examine whether metformin (MET) can protect against the neurotoxicity caused by DOX treatment. Forty male rats were divided into four groups (10 rats/group): control, DOX, DOX + MET, and MET. Rats treated with DOX received five doses of 4 mg/kg DOX weekly (cumulative dose: 20 mg/kg). For the DOX-MET and MET groups, MET (3 mg/mL) was dissolved in drinking water. Behavioral and glucose tests were performed one day after treatment was completed. We found DOX (4 mg/kg/week, 5 weeks) caused learning and memory impairment in the Y-maze, novel object recognition, and elevated plus maze behavioral tests. MET did not rescue these DOX-induced memory impairments. Neither DOX nor MET nor MET + DOX altered glucose levels following the treatment. In summary, DOX treatment is associated with memory impairment in rats, but MET does not rescue this cognitive dysfunction.

Age-dependent brain volume and neuropsychological changes after chemotherapy in breast cancer patients

This study investigated volumetric brain changes and cognitive performance in premenopausal and postmenopausal patients treated for early-stage breast cancer. Participants underwent elaborate neurocognitive assessments (neuropsychological testing, cognitive failure questionnaire, and high-resolution T1-weighted structural MRI) before and after chemotherapy. Volumetric brain changes were estimated, using longitudinal deformation-based morphometry, and correlated with cognitive changes. In total, 180 women participated in this study, of whom 72 patients with breast cancer had received adjuvant chemotherapy (C+), 49 patients did not receive chemotherapy (C-), and 59 healthy controls (HC). The population was categorized into two age groups: A young group who were premenopausal and younger than 52 years at baseline (n = 55C+/32C-/41HC), and an older group who were postmenopausal and older than 60 years (n = 17C+/17C-/18HC). Cognitive impairment occurred after chemotherapy in both young and older patients, although older patients showed more decline in processing speed (Trail making test b). White matter volume expansion was observed after chemotherapy, only significantly present in the younger subgroup of patients. In patients not treated with chemotherapy, diffuse gray and white matter volume reduction was observed. Less white matter expansion concurred with more cognitive decline (r > .349, p < .05). In conclusion, we found age-dependent cognitive decline and white matter volume changes in patients with breast cancer after chemotherapy, which could possibly be linked to neuroinflammatory processes. White matter expansion after chemotherapy, more pronounced in premenopausal patients, correlated with less cognitive decline. This suggests such expansion to be age-dependent, possibly caused by a protective response in the younger brain to chemotherapy-induced neurotoxicity.

Cognitive complaints in cancer survivors and expectations for support: Results from a web-based survey

Background

Cognitive complaints are common in cancer survivors. We aimed to assess cognitive complaints in cancer survivors and the associated factors using a large web–based survey.

Methods

This online survey was proposed to cancer survivors. Participants completed several questions on cognitive complaints experience, expectations for support of cognitive difficulties, preexisting knowledge about chemotherapy–associated cognitive problems and demographic and medical variables. We used multivariable logistic regression models to estimate Odds Ratios and 95% confidence intervals to estimate associations.

Results

Among 1610 eligible participants (median age 52 [21‐84]), >85% (n = 1393) were breast cancer survivors. Median postcancer treatment time (excluding hormone therapy) was 2.83 years [0.8‐33]. Seventy five percent of the participants (n = 1214) reported cognitive complaints related to cancer treatments. Cognitive difficulties had an impact on work resumption for 76% of the participants (n = 754/982). Most cancer survivors would like to receive support (75%, n = 909) and especially cognitive training (72%, n = 658). Chemotherapy was strongly associated with cognitive complaints (multivariable OR = 3.67, 95% CI: 2.80‐4.82). Self–reported sleep difficulties (OR_{often vs. never} = 2.84, 95% CI: 1.80‐4.47), preexisting knowledge about chemotherapy–associated cognitive problems (OR_{No vs. Yes} = 1.69, 95% CI: 1‐29‐2.22) and age (OR_{21‐64 vs. ≥65} = 0.37, 95% CI: 0.23‐0.58) were also associated with cancer–related cognitive complaints.

Conclusions

According to this large web–based survey including mainly breast cancer survivors, cognitive complaints were reported by three quarters of participants, which reinforces that cognitive difficulties are a major issue in cancer survivors. Chemotherapy, self–reported sleep difficulties and preexisting knowledge about chemotherapy–associated cognitive problems were strongly associated with cancer–related cognitive complaints. Most cancer survivors wished to receive support and especially cognitive training.

Relationship of fatigue with cognitive performance in women with early-stage breast cancer over 2 years

OBJECTIVE

Fatigue and cognitive dysfunction are major concerns for women with early-stage breast cancer during treatment and into survivorship. However, interrelationships of these phenomena and their temporal patterns over time are not well documented, thus limiting the strategies for symptom management interventions. In this study, changes in fatigue across treatment phases and the relationship among fatigue severity and its functional impact with objective cognitive performance were examined.

METHODS

Participants (N = 75) were assessed at five time points beginning prior to chemotherapy to 24 months after initial chemotherapy. Fatigue severity and impact were measured on the Brief Fatigue Inventory. Central nervous system (CNS) Vital Signs was used to measure performance based cognitive testing. Temporal changes in fatigue were examined, as well as the relationship between fatigue and cognitive performance, at each time point using linear mixed effect models.

RESULTS

Severity of fatigue varied as a function of phase of treatment. Fatigue severity and its functional impact were moderate at baseline, increased significantly during chemotherapy, and returned to near baseline levels by 2 years. At each time point, fatigue severity and impact were significantly associated with diminished processing speed and complex attention performance.

CONCLUSIONS

A strong association between fatigue and objective cognitive performance suggests that they are likely functionally related. That cognitive deficits were evident at baseline, whereas fatigue was more chemotherapy dependent, implicates that two symptoms share some common bases but may differ in underlying mechanisms and severity over time. This knowledge provides a basis for introducing strategies for tailored symptom management that vary over time.

'A new normal with chemobrain': Experiences of the impact of chemotherapy-related cognitive deficits in long-term breast cancer survivors

Chemobrain is one of the most commonly reported side-effects of cancer treatment. However, there is limited research into its psychosocial concomitants. This study aimed to explore the long-term lived experience of chemobrain. Interpretative phenomenological analysis allowed an in-depth investigation of 12 breast cancer survivors suffering from perceived cognitive deficits at least 1-year post-treatment. Themes were organised around the illness representations framework. Commonly reported cognitive deficits related to memory, language and processing speed, which affected participants’ sense of identity and their interactions with others. Individual experiences were mediated by health beliefs regarding controllability, validation and impairment trajectory.

Methotrexate Chemotherapy Induces Persistent Tri-glial Dysregulation that Underlies Chemotherapy-Related Cognitive Impairment

Chemotherapy results in a frequent yet poorly understood syndrome of long-term neurological deficits. Neural precursor cell dysfunction and white matter dysfunction are thought to contribute to this debilitating syndrome. Here, we demonstrate persistent depletion of oligodendrocyte lineage cells in humans who received chemotherapy. Developing a mouse model of methotrexate chemotherapy-induced neurological dysfunction, we find a similar depletion of white matter OPCs, increased but incomplete OPC differentiation, and a persistent deficit in myelination. OPCs from chemotherapy-naive mice similarly exhibit increased differentiation when transplanted into the microenvironment of previously methotrexate-exposed brains, indicating an underlying microenvironmental perturbation. Methotrexate results in persistent activation of microglia and subsequent astrocyte activation that is dependent on inflammatory microglia. Microglial depletion normalizes oligodendroglial lineage dynamics, myelin microstructure, and cognitive behavior after methotrexate chemotherapy. These findings indicate that methotrexate chemotherapy exposure is associated with persistent tri-glial dysregulation and identify inflammatory microglia as a therapeutic target to abrogate chemotherapy-related cognitive impairment. VIDEO ABSTRACT.

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.