Role of Cytokines in Chemotherapy-related Cognitive Impairment of Breast Cancer Patients: A Systematic Review.

BACKGROUND: Cognitive impairment is one of the most common problems experienced by patients receiving chemotherapy, and evidence suggests that cytokines might play an important role. Various studies were conducted to evaluate the role of cytokines in chemotherapy-related cognitive impairment (CRCI). However, the association between CRCI due to cytokines is not well-established. Thus, this systematic review aims to assess the role of cytokines in CRCI in breast cancer patients. METHODS: This systematic review was conducted according to the Preferred Reporting Item for Systematic Review and Meta-analysis (PRISMA) guidelines. An intense literature search was carried out for inclusion criteria in major databases, including PubMed and Clinicaltrials.gov, in August 2021. Studies assessing cognitive parameters through objective and subjective assessment in breast cancer patients receiving chemotherapy were included. RESULTS: A total of 4052 studies were identified, and 15 studies were included in this systematic review. We found that IL-6, IL-1ß, and TNF-α were associated with varying degrees of cognitive impairment in breast cancer patients receiving chemotherapy. CONCLUSION: This systematic review showed a correlation between various cytokines and chemotherapy- associated cognitive decline in breast cancer patients.

Evaluating patient-reported symptoms and late adverse effects following completion of first-line chemotherapy for ovarian cancer using the MOST (Measure of Ovarian Symptoms and Treatment concerns).

OBJECTIVES: Knowledge on the course of symptoms patients with ovarian cancer experience is limited. We documented the prevalence and trajectories of symptoms after first-line chemotherapy using the Measure of Ovarian Symptoms and Treatment concerns (MOST). METHODS: A total of 726 patients who received platinum-based chemotherapy for ovarian cancer were asked to complete the MOST every 3 months, beginning 6 months post-diagnosis and continuing for up to 4 years. We used descriptive statistics to examine temporal changes in MOST-S26 index scores for disease or treatment-related (MOST-DorT), neurotoxicity (MOST-NTx), abdominal (MOST-Abdo), and psychological (MOST-Psych) symptoms, and wellbeing (MOST-Wellbeing) and selected individual symptoms. We used group-based trajectory models to identify groups with persistently poor symptoms. RESULTS: The median MOST-Abdo, MOST-DorT and MOST-Wellbeing score were worst at chemotherapy-end but improved and stabilised by 1, 3 and 12 months after treatment, respectively. The median MOST-NTx score peaked at 1 month after treatment before improving, while the median MOST-Psych score did not change substantially over time. Long-term moderate-to-severe fatigue (32%), trouble sleeping (31%), sore hands and feet (21%), pins and needles (20%) and anxiety (18%) were common. Trajectory models revealed groups of patients with persistent symptoms had MOST-DorT scores above 30 and MOST-NTx scores above 40 at treatment-end. CONCLUSIONS: Although many patients report improvements in symptoms by 3 months after first-line chemotherapy for ovarian cancer, patients who score > 30/100 on MOST-S26-DorT or > 40/100 on MOST-S26-NTx at the end of chemotherapy are likely to have persistent symptoms. The MOST could triage this at-risk subset for early intervention.

The diuretic amiloride attenuates doxorubicin-induced chemobrain in rats: Behavioral and mechanistic study.

Cognitive impairment or "chemobrain" is a troublesome adverse effect which had been increasingly reported by cancer patients after doxorubicin (DOX) chemotherapy. Notably, Hypertension, a very common comorbidity in cancer patients, could pose a greater risk for negative cognitive outcomes. Amiloride (AML) is an antihypertensive, potassium-sparing diuretic that has been proven to be neuroprotective in different experimental models; this can be attributed to its ability to inhibit different ion transporters such as Na+/H+ exchanger (NHE), which upon excessive activation can result in intracellular cationic overload, followed by oxidative damage and cellular death. Accordingly, this study was designed to investigate the potential neuroprotective effect of AML against DOX-induced chemobrain and to elucidate possible underlying mechanisms. Briefly, Histopathological examination and neurobehavioral testing (Morris water maze, Y maze and passive avoidance test) showed that AML co-treatment (10 mg/kg/day) markedly attenuated DOX (2 mg/kg/week)-induced neurodegeneration and memory impairment after 4 weeks of treatments. We found that DOX administration up-regulated NHE expression and increased lactic acid content in the hippocampus which were markedly opposed by AML. Moreover, AML mitigated DOX-induced neuroinflammation and decreased hippocampal tumor necrosis factor-α level, nuclear factor kappa-B, and cyclooxygenase-2 expression. Additionally, AML counteracted DOX-induced hippocampal oxidative stress as indicated by normalized malondialdehyde and glutathione levels. Furthermore, AML halted DOX-induced hippocampal apoptosis as evidenced by decreased caspase-3 activity and lower cytochrome c immunoexpression. Our results in addition to the previously reported antitumor effects of AML and its ability to mitigate cancer resistance to DOX therapy could point toward possible new repositioning scenarios of the diuretic AML especially regarding hypertensive cancer patients.

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.

Associations of healthcare providers' awareness, perception, and knowledge of chemotherapy-induced cognitive impairment and their intentions to provide information about it to patients.

OBJECTIVE: Most recent oncology studies support the existence of chemotherapy-induced cognitive impairment. This study's objective was to evaluate the power of healthcare providers' knowledge, awareness, and perception of memory impairment caused by chemotherapeutic agents, as predictors of their intentions to convey information about this side effect to patients. MATERIALS AND METHODS: A cross-sectional online survey with 32 questions and seven domains was distributed. The domains included questions about healthcare providers' behaviors, norms, attitudes, awareness, perceptions, and knowledge about chemotherapeutic agent-induced cognitive impairment and their intentions to inform patients about these side effects. Descriptive and inferential statistics were calculated to analyze associations. RESULTS: A total of 207 healthcare providers completed the survey. Their mean age was 31 (±7.8) years and most of them were physicians (43.5%). Positive relationships were found between healthcare providers' attitudes (ß=0.239, p<0.001), subjective norms (ß=0.219, p<0.001), behavioral control (ß=0.284, p<0.001), and intentions to provide information to patients. Their awareness was positively associated with their age (ß=0.127, p<0.001), and their (or their relatives') receipt of chemotherapeutic agents (ß=1.363, p=0.04); however, a negative relationship was found with physician specialists (ß=-2.659, p<0.001) and Saudi nationality (ß=-2.919, p<0.001). A negative correlation was found between healthcare givers' perceptions and physician specialists (ß=-1.487, p=0.003), and a positive association with participants' total knowledge (ß=0.765, p<0.001). Univariate linear regression analysis of participants' knowledge showed a negative relationship with Saudi nationality (ß= -0.835, p<0.001) and physician specialists (ß= -0.519, p=0.003). CONCLUSIONS: Providers' low scores on awareness, perceptions, and knowledge of these side effects of treatment highlight a need for strategic educational programs that meet patients' needs and improve their quality of life.

Recent progress in the elucidation of the mechanisms of chemotherapy-induced cognitive impairment.

The term "chemobrain" refers to the cognitive dysfunction that occurs after chemotherapy, and it is also known as chemotherapy-induced cognitive impairment or "chemofog". The aim of this review is to bring together the findings of existing literature on the topic and summarize the current knowledge on the potential mechanisms of chemobrain. According to the reviewed studies, the mechanisms by which chemotherapy could cause chemobrain include disruption of hippocampal cell proliferation and neurogenesis, hormonal changes, increased oxidative stress and reactive oxygen species production, chronic increase in inflammation, and alterations in synaptic plasticity and long-term potentiation. While the effects of inflammation and oxidative stress on neurogenesis and their role in chemotherapy-induced cognitive impairment have been widely studied, the chemotherapy-induced cognitive impairment mechanisms that involve mitochondrial dysfunction, estrogen dysregulation, and increased transglutaminase 2 are still unclear. Further studies on these mechanisms are necessary to understand the effects of chemotherapy at the cellular and molecular level and facilitate the development of preventive and therapeutic strategies against chemotherapy-associated cognitive impairment or chemobrain.

Motopsin deficiency imparts partial insensitivity to doxorubicin-induced hippocampal impairments in adult mice.

Motopsin is a serine protease that plays a crucial role in synaptic functions. Loss of motopsin function causes severe intellectual disability in humans. In this study, we evaluated the role of motopsin in the neuropathological development of cognitive impairments following chemotherapy, also known as chemobrain. Motopsin knockout (KO) and wild-type (WT) mice were intravenously injected with doxorubicin (Dox) or saline four times every 8 days and were evaluated for open field, novel object recognition, and passive avoidance tests. Parvalbumin-positive neurons in the hippocampus were immunohistochemically analyzed. Dox administration significantly decreased the total distance in the open field test in both WT and motopsin KO mice without affecting the duration spent in the center square. A significant interaction between the genotype and drug treatment was detected in the recognition index (the rate to investigate a novel object) in the novel object recognition test, although Dox treatment did not affect the total investigation time. Additionally, Dox treatment significantly decreased the recognition index in WT mice, whereas it tended to increase the recognition index in motopsin KO mice. Dox treatment did not affect the latency to enter a dark compartment in either WT or motopsin KO mice in the passive avoidance test. Interestingly, Dox treatment increased the parvalbumin-positive neurons in the stratum oriens of the hippocampus CA1 region of only WT mice, not motopsin KO mice. Our data suggest that motopsin deficiency imparted partial insensitivity to Dox-induced hippocampal impairments. Alternatively, motopsin may contribute to the neuropathology of chemobrain.

The Promise of Nutrient-Derived Bioactive Compounds and Dietary Components to Ameliorate Symptoms of Chemotherapy-Related Cognitive Impairment in Breast Cancer Survivors.

OPINION STATEMENT: One of the most burdensome symptoms reported by breast cancer patients is chemotherapy-related neurocognitive impairment. It is estimated that of the 11 million cancer survivors in the USA, 22% of them are breast cancer patients. The National Cancer Institute classified chemotherapy-related cognitive impairment (CRCI) as one of the most debilitating sequelae of cancer therapy, limiting this patient population from recommencing their lives prior to the diagnosis of breast cancer. Currently, there are no strategies that are established to prevent, mitigate, or treat CRCI. In addition to surviving cancer, quality of life is critical to cancer survivors. Based on the multiple and complex biological and psychosocial etiology, the varying manifestation and extent of cognitive decline documented in breast cancer survivors, possibly attributed to varying combinations of chemotherapy and dose and duration of therapy, multimodal interventions combining promising nutrient-derived bioactive compounds with antioxidant and anti-inflammatory properties, in addition to structured cognitive training and exercise regimens, can work synergistically to reduce inflammation and oxidative stress with significant improvement in cognitive function resulting in improvements in quality of life of breast cancer survivors.

Berberine ameliorates doxorubicin-induced cognitive impairment (chemobrain) in rats.

AIMS: Cognitive decline is one of the most challenging issues for cancer survivors undergoing doxorubicin (DOX) based chemotherapy. Oxidative stress and inflammation primarily through tumor necrosis factor-alpha (TNF-α) are considered the key contributors to DOX-induced chemobrain. Berberine (BBR) has attracted much interest because of its anti-oxidative, anti-inflammatory and anti-apoptotic actions. This study aimed to evaluate the potential neuroprotective effect of BBR in DOX-induced neurodegeneration and cognitive deficits. MATERIALS AND METHODS: Chemobrain was induced by DOX i.p. injection at the dose of 2 mg/kg, once/week, for four consecutive weeks. Rats were treated with BBR (100 mg/kg, p.o.) for 5 days/week for four consecutive weeks. KEY FINDINGS: BBR significantly attenuated behavioral defects in DOX-induced cognitive impairment. Besides, BBR reversed histopathological abnormalities. Mechanistically, it reversed DOX-induced neuroinflammation by attenuating NF-κB gene and protein expression in addition to diminishing expression of pro-inflammatory mediators (TNF-α and IL-1ß), as well as apoptotic related factors (Bax, Bcl2 and Bax/Bcl2 ratio). Additionally, BBR activated the anti-oxidative defense via upregulating the expression of peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α) and manganese superoxide dismutase (MnSOD). BBR improved synaptic plasticity through cAMP response element-binding protein (CREB) and brain-derived neurotrophic factor (BDNF). These effects were related through the modulation of Sirtuin1 (SIRT1) expression. SIGNIFICANCE: BBR is highlighted to induce neuroprotection against DOX-induced cognitive decline through modulating brain growth factors and imposing an anti-inflammatory, anti-apoptotic and anti-oxidative effects.

Cognitive Functions under Anti-HER2 Targeted Therapy in Cancer Patients: A Scoping Review.

Pharmacological therapy targeting the HER2 protein is one of the major breakthroughs in the treatment of cancer patients overexpressing HER2 who have increased survival rates. Despite improved survival, it is important to determine the less frequent adverse effects in order to tailor treatments more personalized to the patients' features. The possible impact of cancer treatments on cognitive functions is huge, and the effects of anti-HER 2 therapies on this issue have not been reviewed and are the objective of this study. Analysis of PubMed, Scopus, Cochrane library and Web of Science databases revealed six studies performed in breast and serous uterine cancer patients analyzing cognitive function under chemotherapy regimens including anti-HER2 drugs. Four of these studies reported small to significant worsening of cognitive function following chemotherapy regimens containing trastuzumab (the most widely used anti-HER2 drug). In neoadjuvant settings, and in breast cancer patients, treatment with the new anti-HER-2 drug trastuzumab emtansine seems to induce less cognitive impairment than therapeutic regimens containing chemotherapy and trastuzumab. Acute administration of trastuzumab induced cognitive impairment in gastric cancer mice models, confirming its ability to alter cognitive function in patients. More studies analyzing the impact of anti-HER2 therapy on cognitive function are necessary at preclinical and clinical levels in order to personalize pharmacological treatment and offer cancer patients a better quality of life.

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

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

Astrocytes rescue neuronal health after cisplatin treatment through mitochondrial transfer.

Neurodegenerative disorders, including chemotherapy-induced cognitive impairment, are associated with neuronal mitochondrial dysfunction. Cisplatin, a commonly used chemotherapeutic, induces neuronal mitochondrial dysfunction in vivo and in vitro. Astrocytes are key players in supporting neuronal development, synaptogenesis, axonal growth, metabolism and, potentially mitochondrial health. We tested the hypothesis that astrocytes transfer healthy mitochondria to neurons after cisplatin treatment to restore neuronal health.We used an in vitro system in which astrocytes containing mito-mCherry-labeled mitochondria were co-cultured with primary cortical neurons damaged by cisplatin. Culture of primary cortical neurons with cisplatin reduced neuronal survival and depolarized neuronal mitochondrial membrane potential. Cisplatin induced abnormalities in neuronal calcium dynamics that were characterized by increased resting calcium levels, reduced calcium responses to stimulation with KCl, and slower calcium clearance. The same dose of cisplatin that caused neuronal damage did not affect astrocyte survival or astrocytic mitochondrial respiration. Co-culture of cisplatin-treated neurons with astrocytes increased neuronal survival, restored neuronal mitochondrial membrane potential, and normalized neuronal calcium dynamics especially in neurons that had received mitochondria from astrocytes which underlines the importance of mitochondrial transfer. These beneficial effects of astrocytes were associated with transfer of mitochondria from astrocytes to cisplatin-treated neurons. We show that siRNA-mediated knockdown of the Rho-GTPase Miro-1 in astrocytes reduced mitochondrial transfer from astrocytes to neurons and prevented the normalization of neuronal calcium dynamics.In conclusion, we showed that transfer of mitochondria from astrocytes to neurons rescues neurons from the damage induced by cisplatin treatment. Astrocytes are far more resistant to cisplatin than cortical neurons. We propose that transfer of functional mitochondria from astrocytes to neurons is an important repair mechanism to protect the vulnerable cortical neurons against the toxic effects of cisplatin.

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.

Polydatin ameliorates chemotherapy-induced cognitive impairment (chemobrain) by inhibiting oxidative stress, inflammatory response, and apoptosis in rats.

Most breast cancer survivors receiving chemotherapy have severe cognitive impairment, often referred to as "chemobrain." Polydatin (PLD) is known to have many biological activities. Thus, this study aimed to determine whether symptoms of chemobrain can be prevented or relieved by PLD. The chemobrain models were established by intraperitoneal injection of doxorubicin (DOX, 2 mg/kg) in rats once a week for 4 weeks (DOX group and DOX+PLD group). In the PLD group and DOX+PLD group, PLD (50 mg/kg) was administered orally to rats every day. We found that PLD treatment significantly protected against DOX-induced learning and memory impairment, restored hippocampal histopathological architecture. Furthermore, PLD suppressed DOX-induced oxidative stress through up-regulating Nrf2, inhibited inflammatory response by activating the NF-κB pathway, and reduced hippocampal apoptosis. Therefore, the present study indicated that PLD offered neuroprotection against DOX-induced chemobrain. PLD may assist in preventing chemobrain after chemotherapy in patients with cancers.