Acute transient encephalopathy after weekly paclitaxel infusion

Lycopene mitigates paclitaxel-induced cognitive impairment in mice; Insights into Nrf2/HO-1, NF-κB/NLRP3, and GRP-78/ATF-6 axes

Chemotherapy-induced cognitive impairment, referred to as "chemobrain", is widely acknowledged as a significant adverse effect of cancer therapy. Paclitaxel, a chemotherapeutic drug, has been reported to cause cognitive impairment clinically and in animal models. However, the precise mechanisms are not fully understood. The current study explored the potential neuroprotective effect of lycopene in paclitaxel-induced cognitive impairment in mice and its potential underlying mechanisms. Mice were randomly allocated into six groups: control, paclitaxel-treated (10 mg/kg), lycopene-treated (5, 10, and 20 mg/kg) + paclitaxel, and lycopene alone-treated (20 mg/kg) groups. The effect of lycopene treatment on behavioral function and histological examination was assessed. Lycopene (20 mg/kg) was selected for additional investigation into the underlying mechanisms. Lycopene treatment counteracted paclitaxel-induced oxidative stress by reducing lipid peroxidation and enhancing catalase levels. Additionally, lycopene-treated mice demonstrated a significant elevation in nuclear factor erythroid 2-related factor 2 with no significant effect on hemeoxygenase-1. Moreover, paclitaxel administration elevated endoplasmic reticulum stress markers; glucose-regulated protein78, activating Transcription Factor 6, C/EBP homologous protein, and apoptosis marker annexin V which were significantly reduced by lycopene treatment. Furthermore, lycopene mitigated paclitaxel-induced neuroinflammation through the reduction of the levels of the NLR Family Pyrin Domain Containing 3 (NLRP3) inflammasome axis markers; nuclear factor-κB, NLRP3, caspase-1, interleukin-1β, and interleukin-18. Our study findings may provide new evidence that lycopene mitigates paclitaxel-induced cognitive impairment in mice by reversing oxidative stress, endoplasmic reticulum stress, and inflammatory mechanisms.

Critical illness-associated weakness and related motor disorders

Weakness of limb and respiratory muscles that occurs in the course of critical illness has become an increasingly common and serious complication of adult and pediatric intensive care unit patients and a cause of prolonged ventilatory support, morbidity, and prolonged hospitalization. Two motor disorders that occur singly or together, namely critical illness polyneuropathy and critical illness myopathy, cause weakness of limb and of breathing muscles, making it difficult to be weaned from ventilatory support, commencing rehabilitation, and extending the length of stay in the intensive care unit, with higher rates of morbidity and mortality. Recovery can take weeks or months and in severe cases, and may be incomplete or absent. Recent findings suggest an improved prognosis of critical illness myopathy compared to polyneuropathy. Prevention and treatment are therefore very important. Its management requires an integrated team approach commencing with neurologic consultation, creatine kinase (CK) measurement, detailed electrodiagnostic, respiratory and neuroimaging studies, and potentially muscle biopsy to elucidate the etiopathogenesis of the weakness in the peripheral and/or central nervous system, for which there may be a variety of causes. These tenets of care are being applied to new cases and survivors of the coronavirus-2 disease pandemic of 2019. This chapter provides an update to the understanding and approach to critical illness motor disorders.

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.

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

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

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

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

Chemotherapy-induced posterior reversible encephalopathy syndrome: Three case reports

RATIONALE

Posterior reversible encephalopathy syndrome (PRES) has been associated with the use of several medications, including chemotherapeutic agents.

PATIENT CONCERNS

A 65-year-old woman was diagnosed with adenocarcinoma of the ovary, after sixth-line treatment with topotecan, at the beginning of the fourth cycle, she was admitted to the emergency room for presenting tonic-clonic seizures, visual disturbance, and hypertension. A 66-year-old woman was diagnosed with bilateral breast cancer; due to disease progression, treatment with paclitaxel and gemcitabine was started, 1 month after the last dose of chemotherapy, she was admitted to the emergency room for suffering severe headache, altered mental status, tonic-clonic seizures, and hypertension. A 60-year-old patient diagnosed with breast cancer on the left side, underwent second-line chemotherapy with gemcitabine, carboplatin, and bevacizumab, and 1 month after the last dose of chemotherapy, she was also admitted to the emergency room due to altered mental status, vomiting, tonic-clonic seizures, and hypertension.

DIAGNOSIS

They were diagnosed as PRES based on physical examination, laboratory findings, and imaging techniques that revealed diffuse lesions and edema within the parieto-occipital regions.

INTERVENTIONS

They received support treatment with blood pressure (BP) control, seizures were controlled with a single anti-epileptic agent, and chemotherapeutic agents from the onset of PRES to its resolution were discontinued.

OUTCOMES

All these patients improved after medical treatment was started.

LESSONS

Medical personnel and therapeutic establishments need to be made aware about this chemotherapy-induced neurologic complication.

Non-convulsive seizure related to Cremophor EL™-free, polymeric micelle formulation of paclitaxel: a case report

Paclitaxel is a chemotherapeutic agent that is effective against ovarian, breast, lung, and other cancers. Although peripheral neurotoxicity is among the most common side effects of paclitaxel treatment, central neurotoxicity is rarely reported. When centrally mediated side effects are observed, they are attributed to Cremophor EL™ (CrEL), a surfactant-containing vehicle used for paclitaxel administration. In the present report, we discuss the case of a 72-year-old woman with ovarian carcinoma who experienced a non-convulsive seizure following administration of a CrEL-free, polymeric micelle formulation of paclitaxel. One week after her fourth round of chemotherapy, she experienced a transient episode of aphasia for 45 minutes. Electroencephalography demonstrated epileptiform discharges. To our knowledge, this is the first reported case of seizure associated with a CrEL-free formulation of paclitaxel. Although rare, patients and clinicians should remain aware of the risk of non-convulsive seizure following infusion of this paclitaxel formulation.

The chemotherapeutic agent paclitaxel selectively impairs learning while sparing source memory and spatial memory

Chemotherapeutic agents are widely used to treat patients with systemic cancer. The efficacy of these therapies is undermined by their adverse side-effect profiles such as cognitive deficits that have a negative impact on the quality of life of cancer survivors. Cognitive side effects occur across a variety of domains, including memory, executive function, and processing speed. Such impairments are exacerbated under cognitive challenges and a subgroup of patients experience long-term impairments. Episodic memory in rats can be examined using a source memory task. In the current study, rats received paclitaxel, a taxane-derived chemotherapeutic agent, and learning and memory functioning was examined using the source memory task. Treatment with paclitaxel did not impair spatial and episodic memory, and paclitaxel treated rats were not more susceptible to cognitive challenges. Under conditions in which memory was not impaired, paclitaxel treatment impaired learning of new rules, documenting a decreased sensitivity to changes in experimental contingencies. These findings provide new information on the nature of cancer chemotherapy-induced cognitive impairments, particularly regarding the incongruent vulnerability of episodic memory and new learning following treatment with paclitaxel.