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

LC-qTOF-MS/MS phytochemical profiling of Tabebuia impetiginosa (Mart. Ex DC.) Standl. leaf and assessment of its neuroprotective potential in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Tabebuia impetiginosa (Bignoniaceae) was traditionally used for memory enhancement and central nervous system (CNS) stimulation.

AIM OF THE STUDY

This study aims to create a metabolic profile of the ethyl acetate fraction of T. impetiginosa (TEF) and investigate for the first time its neuroprotective potential on cyclophosphamide (CP)-induced chemobrain, validating its traditional use.

MATERIALS AND METHODS

Metabolite profiling of TEF was performed using Liquid Chromatography coupled with Quadrupole Time of Flight-Mass/Mass Spectrometry (LC-qTOF-MS/MS). For the in vivo study, CP (200 mg/kg, i.p.) was administered to induce cognitive impairment in rats; TEF (30 mg/kg, p.o.) was administered throughout the 14 days of the experiment to assess its role in mitigating CP-induced neuronal deficits. Behavioral tests including locomotor, Y-maze, and passive avoidance tests were conducted. Additionally, biochemical markers such as reduced glutathione (GSH), malondialdehyde (MDA), tumor necrosis factor-α (TNF-α), and caspase-3 immunoexpression were assessed in the hippocampus area.

RESULTS

Forty-four phytoconstituents were tentatively identified in TEF, mainly iridoids and organic acids. TEF showed significant memory enhancement as evidenced by the increase in step-through latency in the passive avoidance test by 1.5 folds and the increase in sequence alternation percentage (SAP) in the Y-maze test by 67.3%, as compared to CP-group. Moreover, it showed pronounced antioxidant and anti-inflammatory potentials evidenced by the significant elevation in reduced glutathione (GSH) levels by 80% and a pronounced decline in MDA and TNF-α levels by 24% and 45%, respectively relative to the CP group. TEF treatment restored normal hippocampal histological features and attenuated apoptotic caspase-3 expression by 70% compared to the CP group.

CONCLUSIONS

TEF can act as a promising natural scaffold in managing the chemobrain induced by CP in cancer patients.

Learning and memory deficits produced by aspartame are heritable via the paternal lineage

Environmental exposures produce heritable traits that can linger in the population for one or two generations. Millions of individuals consume substances such as artificial sweeteners daily that are declared safe by regulatory agencies without evaluation of their potential heritable effects. We show that consumption of aspartame, an FDA-approved artificial sweetener, daily for up to 16-weeks at doses equivalent to only 7-15% of the FDA recommended maximum daily intake value (equivalent to 2-4 small, 8 oz diet soda drinks per day) produces significant spatial learning and memory deficits in mice. Moreover, the cognitive deficits are transmitted to male and female descendants along the paternal lineage suggesting that aspartame's adverse cognitive effects are heritable, and that they are more pervasive than current estimates, which consider effects in the directly exposed individuals only. Traditionally, deleterious environmental exposures of pregnant and nursing women are viewed as risk factors for the health of future generations. Environmental exposures of men are not considered to pose similar risks. Our findings suggest that environmental exposures of men can produce adverse impact on cognitive function in future generations and demonstrate the need for considering heritable effects via the paternal lineage as part of the regulatory evaluations of artificial sweeteners.

Cognitive impairment after cancer treatment: mechanisms, clinical characterization, and management

Cognitive impairment is a debilitating side effect experienced by patients with cancer treated with systemically administered anticancer therapies. With around 19.3 million new cases of cancer worldwide in 2020 and the five year survival rate growing from 50% in 1970 to 67% in 2013, an urgent need exists to understand enduring side effects with severe implications for quality of life. Whereas cognitive impairment associated with chemotherapy is recognized in patients with breast cancer, researchers have started to identify cognitive impairment associated with other treatments such as immune, endocrine, and targeted therapies only recently. The underlying mechanisms are diverse and therapy specific, so further evaluation is needed to develop effective therapeutic interventions. Drug and non-drug management strategies are emerging that target mechanistic pathways or the cognitive deficits themselves, but they need to be rigorously evaluated. Clinically, consistent use of objective diagnostic tools is necessary for accurate diagnosis and clinical characterization of cognitive impairment in patients treated with anticancer therapies. This should be supplemented with clinical guidelines that could be implemented in daily practice. This review summarizes the recent advances in the mechanisms, clinical characterization, and novel management strategies of cognitive impairment associated with treatment of non-central nervous system cancers.

Heterotopic 4T1 breast cancer transplantation induces hippocampal inflammation and depressive-like behaviors in mice

Cancer and its accompanying treatments can lead to numerous physical and emotional concerns, including subclinical or clinical depression and anxiety, which could significantly impact one's well-being, quality of life, and survival. A large number of studies have elucidated that neuroinflammation is associated with depression. Here, we report the hippocampal pathological changes and depressive behaviors of a heterotopic breast cancer transplantation mouse model; hence, a heterotopic 4T1 breast cancer transplantation mouse model was established. Assessment of cognitive and locomotive functions of the experimental animals was conducted using open- and closed-field tests, including a tail suspension test. Expression levels of monoaminergic system markers, brain-derived neurotrophic factor (BDNF), pro-inflammatory cytokines, and nuclear factor-kappa B (NFκB) in the hippocampus and serum were detected using immunochemistry and western and enzyme-linked immunosorbent assay analysis. A comparison of the differences between model and control animals was performed. As per our findings, 4T1 tumor-bearing mice displayed cancer-related anorexia/cachexia with significant reductions in the travel distance and the total number of squares crossed in the open- and closed-field tests. Additionally, the 4T1 tumor-bearing mice withstood a more extended period of immobility during the tail suspension test. Immunohistochemistry studies revealed reduced levels of serotonin, norepinephrine, and BDNF in the hippocampus and serum. Elevated levels of NFκB and pro-inflammatory cytokines in the hippocampus were also observed. These findings suggest that hippocampal inflammation may have played an important role in the neurological function and depressive behavior in heterotopic 4T1 breast cancer transplantation mice.

Antidepressant Effects of NSAIDs in Rodent Models of Depression-A Systematic Review

In recent years much focus has been on neuroimmune mechanisms of depression. As a consequence, many preclinical and clinical trials have been performed examining potential antidepressant effects of several anti-inflammatory drugs. The results of such trials have been varied. With the current manuscript we wished to elucidate the effects of non-steroidal anti-inflammatory drugs (NSAIDs) on depressive-like behaviour in rodent models of depression by performing a systematic review of the available literature. We performed a systematic literature search in PubMed for rodent models of depression where NSAIDs were administered and a validated measure of depressive-like behaviour was applied. 858 studies were initially identified and screened using Covidence systematic review software. Of these 36 met the inclusion criteria and were included. The extracted articles contained data from both rat and mouse studies but primarily male animals were used. Several depression models were applied and 17 different NSAIDs were tested for antidepressant effects. Our results suggest that stress models are the best choice when examining antidepressant effects of NSAIDs. Furthermore, we found that rat models provide a more homogenous response than mouse models. Intriguingly, the use of female animals was only reported in three studies and these failed to find antidepressant effects of NSAIDs. This should be explored further. When comparing the different classes of NSAIDs, selective COX-2 inhibitors were shown to provide the most stable antidepressant effect compared to non-selective COX-inhibitors. Suggested mechanisms behind the antidepressant effects were attenuation of neuroinflammation, HPA-axis dysregulation and altered monoamine expression.

Cognitive adverse effects of chemotherapy and immunotherapy: are interventions within reach?

One in three people will be diagnosed with cancer during their lifetime. The community of cancer patients is growing, and several common cancers are becoming increasingly chronic; thus, cancer survivorship is an important part of health care. A large body of research indicates that cancer and cancer therapies are associated with cognitive impairment. This research has mainly concentrated on chemotherapy-associated cognitive impairment but, with the arrival of immunotherapies, the focus is expected to widen and the number of studies investigating the potential cognitive effects of these new therapies is rising. Meanwhile, patients with cognitive impairment and their healthcare providers are eagerly awaiting effective approaches to intervene against the cognitive effects of cancer treatment. In this Review, we take stock of the progress that has been made and discuss the steps that need to be taken to accelerate research into the biology underlying cognitive decline following chemotherapy and immunotherapy and to develop restorative and preventive interventions. We also provide recommendations to clinicians on how to best help patients who are currently experiencing cognitive impairment.

The Causal Role of Magnesium Deficiency in the Neuroinflammation, Pain Hypersensitivity and Memory/Emotional Deficits in Ovariectomized and Aged Female Mice

Purpose

Postmenopausal women often suffer from chronic pain, memory decline and mood depression. The mechanisms underlying the neuronal disorders are not fully understood, and effective treatment is still lacking.

Methods

Oral administration of magnesium-L-threonate was tested to treat the neuronal disorders in ovariectomized and aged female mice. The pain hypersensitivity, memory function and depression-like behaviors were measured with a set of behavioral tests. Western blots, immunochemistry and in situ hybridization were used to assess molecular changes.

Results

Chronic oral administration of magnesium-L-threonate substantially prevented or reversed the chronic pain and memory/emotional deficits in both ovariectomized and aged female mice. We found that phospho-p65, an active form of nuclear factor-kappaB, tumor necrosis factor-alpha and interleukin-1 beta were significantly upregulated in the neurons of dorsal root ganglion, spinal dorsal horn and hippocampus in ovariectomized and aged mice. The microglia and astrocytes were activated in spinal dorsal horn and hippocampus. Calcitonin gene–related peptide, a marker for peptidergic C-fibers, was upregulated in dorsal horn, which is associated with potentiation of C-fiber-mediated synaptic transmission in the model mice. In parallel with neuroinflammation and synaptic potentiation, free Mg²⁺ levels in plasma, cerebrospinal fluid and in dorsal root ganglion neurons were significantly reduced. Oral magnesium-L-threonate normalized the neuroinflammation, synaptic potentiation and Mg²⁺ deficiency, but did not affect the estrogen decline in ovariectomized and aged mice. Furthermore, in cultured dorsal root ganglion neurons, estrogen at physiological concentration elevated intracellular Mg²⁺, and downregulated phospho-p65, tumor necrosis factor-alpha and interleukin-1 beta exclusively in the presence of extracellular Mg²⁺.

Conclusion

Estrogen decline in menopause may cause neuroinflammation by reducing intracellular Mg²⁺ in neurons, leading to chronic pain, memory/emotional deficits. Supplement Mg²⁺ by oral magnesium-L-threonate may be a novel approach for treating menopause-related neuronal disorders.